Biochemical and Biophysical Research Communications, Aug 1, 2002
Ubiquitin-proteasome-dependent protein degradation plays a central role in sepsis-induced muscle ... more Ubiquitin-proteasome-dependent protein degradation plays a central role in sepsis-induced muscle wasting. Because the proteasome degrades proteins into small peptides rather than free amino acids, it is likely that additional mechanisms downstream of the proteasome are involved in sepsis-induced muscle proteolysis. Recent studies suggest that the extralysosomal peptidase tripeptidyl-peptidase II (TPP II) degrades peptides generated by the proteasome. We hypothesized that TPP II expression and activity are increased in skeletal muscle during sepsis. Sepsis was induced in rats by cecal ligation and puncture. Control rats were sham-operated. TPP II activity was determined by using the specific substrate Ala-Ala-Phe-7-amido-4-methylcoumarin (AAF-AMC). TPP II protein and gene expression were determined by Western blot and real-time PCR, respectively. Sepsis resulted in increased activity and protein and gene expression of TPP II in extensor digitorum longus muscles. This result was blunted by the glucocorticoid receptor antagonist RU 38486, indicating that glucocorticoids participate in the upregulation of TPP II in skeletal muscle during sepsis. The results suggest that proteolytic mechanisms downstream of the proteasome may be important for the complete degradation of muscle proteins during sepsis.
INTRODUCTION Emerging data suggests neoadjuvant chemotherapy for resectable pancreatic ductal ade... more INTRODUCTION Emerging data suggests neoadjuvant chemotherapy for resectable pancreatic ductal adenocarcinoma (PDAC) is associated with improved survival. However, less than 40% demonstrate a meaningful radiographic response to NAC. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) has emerged as a new modality to treat PDAC. We hypothesize that NAC plus EUS-RFA can be used in the management of resectable PDAC. METHODS Prospective review of PDAC patients meeting criteria of resectable tumor anatomy that underwent NAC chemotherapy plus EUS-RFA followed by pancreatic resection. Radiographic imaging, perioperative and short-term outcomes were recorded. Surgical pathology specimens were analyzed for treatment response. RESULTS Three eligible patients with resectable PDAC received 4 months of neoadjuvant chemotherapy plus EUS-RFA. One month after completion of neoadjuvant treatment, all 3 patients underwent standard pancreaticoduodenectomy without complications. After a 6 week recovery, all patients completed 2 months of post-op adjuvant chemotherapy. CONCLUSIONS In our institutional experience, this treatment protocol appears safe. Patients tolerated the combination of chemotherapy and endoscopic radiofrequency ablation. Patients underwent pancreatic resection with uneventful recovery. This novel neoadjuvant approach may provide a more effective alternative to chemotherapy alone.
IntroductionIn response to the COVID-19 pandemic, hospitals reported decreased admissions for acu... more IntroductionIn response to the COVID-19 pandemic, hospitals reported decreased admissions for acute surgical diagnoses, but scant data was available to quantify the decrease and its consequences. The objective of this study was to examine the incidence of acute care surgery encounters before and during the COVID-19 pandemic.Materials and MethodsA retrospective cohort study was performed at a single, urban, United States safety-net hospital. Emergency room encounters, admissions, non-elective surgical procedures, patient acuity, and surgical complications were compared before and after the start of the COVID-19 pandemic. The primary outcome of the study was the incidence rate (IR) and incidence rate ratios (IRR) for surgical admissions, laparoscopic appendectomy, and urgent laparoscopic cholecystectomy.ResultsDuring the COVID-19 (exposure) time period, the number of nonelective procedures was 143 (IR 4.76) which was significantly lower than the control periods (n = 431, IR 7.2), P < 0.001. During the COVID-19 exposure period, there were significantly fewer urgent cholecystectomies performed (1.37 per day versus 2.80-2.93 per day, P < 0.001). There was a trend toward fewer appendectomies performed, but not significant. There was little difference in patient acuity between the exposure and control periods. A higher proportion of patients that underwent urgent cholecystectomy during the COVID time period had been seen in the ED in the prior 30 d (22% versus 5.6%).ConclusionsSurgical volume significantly decreased during the COVID-19 pandemic. Management of acute cholecystitis may require re-evaluation as nonsurgical management appears to increase repeat presentations.
bioRxiv (Cold Spring Harbor Laboratory), Jan 10, 2022
Background and Aims: Pancreatic ductal adenocarcinoma (PDAC) is characterized by resistance to th... more Background and Aims: Pancreatic ductal adenocarcinoma (PDAC) is characterized by resistance to therapy. A major contributing factor to therapeutic failure is profound desmoplasia and a well-documented hypoxic tumor microenvironment (TME). In PDAC, several therapeutic approaches, including chemotherapy and radiation alone or combined with immune checkpoint inhibitors, have shown minimal therapeutic success, placing an imperative need for the discovery and application of innovative treatments. Endoscopic ultrasound guided radiofrequency ablation (EUS-RFA) is a promising immunomodulator therapy for PDAC. In this work, we hypothesized RFA promotes local and systemic stromal and immunomodulating effects that can be identified for new combination therapeutic strategies. Methods: To test our hypothesis, a syngeneic PDAC mouse model was performed by symmetrically injecting 100k murine KPC cells in bilateral flanks of C57BL/6 female mice. RFA treatment initiated when tumors reached 200-500 mm 3 and was performed only in the right flank. The left flank tumor (non-RFA contralateral side) was used as a paired control for further analysis. Results: RFA promoted a significant reduction in tumor growth rate 4 days after treatment in RFA treated and non-RFA side contralateral tumors from treated mice when compared to controls. Histological analysis revealed a significant increase in expression of cleaved Caspase3 in RFA treated tumors. In addition, collagen deposition and CD31+ cells were significantly elevated in RFA side and non-RFA contralateral tumors from RFA treated mice. Proteome profiling showed changes in C5a and IL-23 in RFA responsive tumors, indicating a role of RFA in modulating intratumoral inflammatory responses. Conclusions: These data indicate RFA promotes local and systemic anti-tumor responses in a syngeneic mouse model of PDAC implicating RFA treatment for local tumors as well as metastatic disease.
The catabolic response to sepsis, severe injury, and burn is characterized by whole-body protein ... more The catabolic response to sepsis, severe injury, and burn is characterized by whole-body protein loss, mainly reflecting increased breakdown of muscle proteins, in particular myofibrillar proteins. Glucocorticoids and various proinflammatory cytokines are important regulators of muscle proteolysis in stressed patients. There is evidence that breakdown of proteins by the ubiquitin-proteasome pathway plays an important role in muscle cachexia, although other mechanisms may participate, such as calcium- and calpain-dependent release of myofilaments from the sarcomere. Three types of treatments have been used to reduce or prevent the catabolic response to injury and sepsis: 1). nutritional, 2). hormonal, and 3). pharmacologic. With regard to nutrition support, it is generally believed that enteral feeding is superior to parenteral feeding and that early feeding is better than late feeding. Although &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;immune-enhancing&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; enteral nutrition has been shown in several recent studies to improve outcome in critically ill patients, the specific effects of these treatments on the catabolic response in muscle are not known. In addition to nutrition support, various hormones, including insulin, growth hormone, and insulin-like growth factor-1, may blunt the catabolic response in patients with stress. Experimental studies have indicated that other treatments may become available in the future, including cytokine antibodies, calcium antagonists, and induction of heat shock response. Methods to prevent or reduce the catabolic response to stress are important considering the significant clinical consequences of muscle cachexia.
Previous studies suggest that increased ubiquitin-proteasome-dependent protein breakdown in vario... more Previous studies suggest that increased ubiquitin-proteasome-dependent protein breakdown in various muscle-wasting conditions may at least in part be mediated by increased cellular calcium levels. The role of calcium in the regulation of proteasome activity, however, is not well understood. We treated cultured L6 myotubes with the calcium ionophore A23187 or thapsigargin, substances that increase intracellular calcium levels through different mechanisms, and measured proteasome activity by determining the degradation of the fluorogenic substrate LLVY-AMC. Treatment of the myotubes with A23187 or thapsigargin resulted in a dose- and time-dependent increase in proteasome activity. When the myotubes were treated with metabolic inhibitors, results suggested that the A23187- and thapsigargin-induced activation of proteasome activity was at least in part regulated by calmodulin, calcium calmodulin-dependent kinase II, caspases, and calpains. The present observations support a role of calcium in the regulation of proteasome-dependent protein breakdown in skeletal muscle and may explain why muscle wasting was reduced by calcium antagonists in previous studies.
American Journal of Physiology-regulatory Integrative and Comparative Physiology, May 1, 2003
Recent studies suggest that the skeletal muscle may be a significant site of IL-6 production in v... more Recent studies suggest that the skeletal muscle may be a significant site of IL-6 production in various conditions, including exercise, inflammation, hypoperfusion, denervation, and local muscle injury. The mediators and molecular mechanisms regulating muscle IL-6 production are poorly understood. We tested the hypothesis that IL-6 production in muscle cells is regulated by IL-1 and that mitogenactivated protein (MAP) kinase signaling and NF-B activation are involved in IL-1-induced IL-6 production. Cultured C2C12 cells, a mouse skeletal muscle cell line, were treated with different concentrations (0.1-2 ng/ml) of IL-1 in the absence or presence of the p38 MAP kinase inhibitor SB-208350 or the p42/44 inhibitor PD-98059. Protein and gene expression of IL-6 were determined by ELISA and real-time PCR, respectively. NF-B DNA binding activity was determined by electrophoretic mobility shift assay and by transfecting myocytes with a luciferase reporter plasmid containing a promoter construct with multiple repeats of NF-B binding site. Treatment of myotubes with IL-1 resulted in a dose-and time-dependent increase of IL-6 production accompanied by an ϳ25-fold increase in IL-6 mRNA levels. IL-1 stimulated NF-B DNA binding activity and gene activation. SB-208350 and PD-98059 inhibited the increase in IL-6 production induced by IL-1. The present results support the concept that skeletal muscle is an important site of IL-6 production. In addition, the results suggest the IL-1 regulates muscle IL-6 production at least in part by activating the MAP kinase pathway and NF-B. interleukin-6 production; cytokines; mitogen-activated protein kinase; nuclear factor-B
Biochemical and Biophysical Research Communications, 2002
Muscle cachexia induced by sepsis, severe injury, cancer, and a number of other catabolic conditi... more Muscle cachexia induced by sepsis, severe injury, cancer, and a number of other catabolic conditions is mainly caused by increased protein degradation, in particular breakdown of myofibrillar proteins. Ubiquitin-proteasome-dependent proteolysis is the predominant mechanism of muscle protein loss in these conditions, but there is evidence that several other regulatory mechanisms may be important as well. Some of those mechanisms are reviewed in this article and they include pre-, para-, and postproteasomal mechanisms. Among preproteasomal mechanisms, mediators, receptor binding, signaling pathways, activation of transcription factors, and modification of proteins are important. Several paraproteasomal mechanisms may influence the trafficking of ubiquitinated proteins and their interaction with the proteasome, including the expression and activity of the COP9 signalosome, the carboxy terminus of heat shock protein 70-interacting protein (CHIP) and valosin-containing protein (VCP). Finally, because the proteasome does not degrade proteins completely into free amino acids but into peptides, postproteasomal degradation of peptides by the giant protease tripeptidyl peptidase II (TPP II) and various aminopeptidases is important in muscle catabolism. Thus, multiple mechanisms and regulatory steps may influence the breakdown of ubiquitinated muscle proteins by the 26S proteasome.
Background: The extent of lymphadenectomy in colon cancer may impact potential to cure and accura... more Background: The extent of lymphadenectomy in colon cancer may impact potential to cure and accuracy of staging. Methods: The Veterans Affairs Central Cancer Registry database was queried for TNM stage I-III colon adenocarcinoma patients and yielded 5,823 individuals. The number of lymph nodes examined, number positive, and the positive:examined lymph node ratio were studied with respect to overall survival by using log-rank and Kaplan-Meier analysis. Results: The overall survival (OS) in stage II patients was greater with the higher number of lymph node (LN) examined. For stage II patients, the 5-year OS was 34%, 43%, 47%, and 55% for the lowest to highest quartiles (P ϭ .007). For stage III patients, the 5-year OS was 31%, 27%, 38%, and 53% for the lowest to highest quartiles (not significant overall). OS is greater with an increased number of positive lymph nodes (P Ͻ .001). The lymph node ratio was more powerful prognostically with a 5-year OS of 27% for the highest quartile versus 44% for the lowest. Conclusions: More extensive lymphadenectomy is associated with improved OS in stage II colon cancer patients. The positive:examined LN ratio is more powerful prognostically than the number of nodes examined or LN positivity.
American Journal of Physiology-regulatory Integrative and Comparative Physiology, Feb 1, 2002
We examined the influence of sepsis, induced by cecal ligation and puncture in rats, on the prote... more We examined the influence of sepsis, induced by cecal ligation and puncture in rats, on the protein and gene expression and hormone binding activity of the glucocorticoid receptor (GR) in skeletal muscle. Sepsis resulted in increased GR mRNA and protein levels and upregulated hormone binding activity in extensor digitorum longus and soleus muscles. Scatchard analysis suggested that the increased GR hormone binding activity reflected an increased number of hormone binding sites, whereas receptor affinity for glucocorticoids was unchanged. The GR antagonist RU-38486 blocked the sepsis-induced increase in GR expression and hormone binding activity, implicating a positive regulatory effect of glucocorticoids on GR expression and binding activity under the present experimental conditions. The results suggest that glucocorticoid-dependent metabolic changes in skeletal muscle during sepsis may reflect not only high circulating glucocorticoid levels but increased amounts and hormone binding activity of the GR as well.
Background: Prognosis after resection of colorectal liver metastases is influenced by various fac... more Background: Prognosis after resection of colorectal liver metastases is influenced by various factors. A positive margin of resection (MOR) has been shown to adversely influence prognosis. Although a 1-cm MOR has been accepted as adequate, the data to support this guideline are sparse. Methods: Our hepatobiliary database was queried for patients who underwent liver resection for colorectal metastases between January 1992 and July 2003. All patients were divided into three groups: MOR <.5 cm (group A), .5 to 1 cm (group B), and >1 cm (group C). Operative reports from each hepatic resection were analyzed to determine local factors that may have contributed to a subcentimeter MOR. Results: A total of 112 patients (67 men and 45 women) underwent liver resection for colorectal metastases with negative margins. Fifty-three patients were in group A, 26 patients were in group B, and 33 patients were in group C. Group C demonstrated decreased local recurrence (LR; P = .003), distant recurrence (DR; P = .008), and disease-free recurrence (P = .002). A significant difference in the overall time to LR (P = .003), time to DR (P = .003), and disease-free survival (P = .002) was also demonstrated. Factors associated with a subcentimeter MOR included nonanatomical resection (P = .043), proximity to a major vessel (P = .003), and central location (P = .002). Conclusions: A <1-cm resection for colorectal liver metastases is associated with increased LR and DR, as well as decreased disease-free survival. When a nonanatomical resection is performed, a MOR >1 cm should be attempted, because an adequate margin is often underestimated. Considerations should be made for extended resections when tumors are centrally located or near major vessels.
American Journal of Physiology-regulatory Integrative and Comparative Physiology, Feb 1, 2002
Sepsis-induced muscle cachexia is associated with increased expression of several genes in the ub... more Sepsis-induced muscle cachexia is associated with increased expression of several genes in the ubiquitin-proteasome proteolytic pathway, but little is known about the activation of transcription factors in skeletal muscle during sepsis. We tested the hypothesis that sepsis upregulates the expression and activity of the transcription factors CCAAT/ enhancer binding protein (C/EBP)- and-␦ in skeletal muscle. Sepsis was induced in rats by cecal ligation and puncture, and control rats were sham operated. C/EBP- and-␦ DNAbinding activity was determined by electrophoretic mobility shift assay and supershift analysis. In addition, C/EBP- and-␦ nuclear protein levels were determined by Western blot analysis. Sepsis resulted in increased DNA-binding activity of C/EBP, and supershift analysis suggested that this reflected activation of the and ␦-isoforms of C/EBP. Concomitantly, C/EBP- and-␦ protein levels were increased in the nuclear fraction of skeletal muscle. In additional experiments, we tested the role of glucocorticoids in sepsis-induced activation of C/EBP- and-␦ by treating rats with the glucocorticoid receptor antagonist RU-38486. This treatment inhibited the sepsis-induced activation of C/EBP- and-␦, suggesting that glucocorticoids participate in the upregulation of C/EBP in skeletal muscle during sepsis. The present results suggest that C/EBP- and-␦ are activated in skeletal muscle during sepsis and that this response is, at least in part, regulated by glucocorticoids. transcription factors; cachexia; proteolysis; ubiquitin; proteasome; CCAAT/enhancer binding protein; deoxyribonucleic acid MUSCLE CACHEXIA during sepsis and various other catabolic conditions, including cancer, burn injury, starvation, and uremia, mainly reflects increased ubiquitinproteasome-dependent protein degradation (10). Muscle wasting in these conditions is associated with increased expression of several genes in the ubiquitinproteasome proteolytic pathway (25, 26
Background. In previous studies, dantrolene prevented sepsis-induced muscle proteolysis, but the ... more Background. In previous studies, dantrolene prevented sepsis-induced muscle proteolysis, but the influence of dantrolene on the expression and activity of the ubiquitin-proteasome proteolytic pathway is not known. In addition, the role of glucocorticoids in the anabolic effect of dantrolene is not well understood. Methods. Sepsis was induced in rats by cecal ligation and puncture (CLP). Other rats underwent shamoperation. Groups of rats were treated with dantrolene (10 mg/kg) administered 2 h before and 8 h after sham-operation or CLP. Sixteen hours after sham-operation or CLP, mRNA levels for ubiquitin, the ubiquitin ligase E3␣, and the 20S proteasome subunit C3 were determined by dot-blot analysis. In additional experiments, the effect of dantrolene on protein degradation was tested in L6 myotubes cultured in the absence or presence of dexamethasone. Results. Treatment of rats with dantrolene prevented the sepsis-induced increase in mRNA levels for ubiquitin, the ubiquitin ligase E3␣, and the 20S proteasome subunit C3. In additional experiments, treatment of cultured myotubes with dantrolene reduced protein degradation in both the absence and the presence of dexamethasone. Conclusions. The results suggest that dantrolene can prevent sepsis-induced activation of the ubiquitinproteasome proteolytic pathway in skeletal muscle and that dantrolene reduces muscle protein degradation independent of glucocorticoids.
Biochemical and Biophysical Research Communications, Mar 1, 2001
Sepsis is associated with increased muscle proteolysis and upregulated transcription of several g... more Sepsis is associated with increased muscle proteolysis and upregulated transcription of several genes in the ubiquitin-proteasome proteolytic pathway. Glucocorticoids are the most important mediator of sepsis-induced muscle cachexia. Here, we examined the influence of sepsis in rats on the transcription factors NF-B and AP-1 in skeletal muscle and the potential role of glucocorticoids in the regulation of these transcription factors. Sepsis was induced by cecal ligation and puncture (CLP). Control rats were sham-operated. NF-B and AP-1 DNA binding activity was determined by electrophoretic mobility shift assay (EMSA) in extensor digitorum longus muscles at different time points up to 16 h after sham-operation or CLP. Sepsis resulted in an early (4 h) upregulation of NF-B activity followed by inhibited NF-B activity at 16 h. AP-1 binding activity was increased at all time points studied during the septic course. When rats were treated with the glucocorticoid receptor antagonist RU38486, NF-B activity increased, whereas AP-1 activity was not influenced by RU38486. The results suggest that NF-B and AP-1 are differentially regulated in skeletal muscle during sepsis and that glucocorticoids may regulate some but not all transcription factors in septic muscle.
Much debate surrounds the one-stage surgical management of acute left colon obstruction. Many sur... more Much debate surrounds the one-stage surgical management of acute left colon obstruction. Many surgeons are still reluctant to perform primary anastomosis in unprepared bowel fearing the risk of anastomotic dehiscence. Although intraoperative lavage and subtotal colectomy have recently proved effective for preventing fecal loading, both of these procedures have drawbacks and the search for additional alternative surgical procedures continues. We conducted an experimental study to examine a new one-stage operation, consisting of the interposition of a jejunal segment to the resection site of the colon, to manage acute left colon obstruction. The colons of 20 domestic pigs were obstructed, and 2 days later, segmental resection and either primary colo-colonic anastomosis or interposition of a jejunal segment was performed. Autopsies were done 6 weeks after the operations and the anastomotic regions were subjected to bursting pressure analysis. The operating time was longer in the interposition group at 49 +/- 14 vs 38 +/- 12 min ( P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). There was no mortality or clinical signs of anastomotic dehiscence in either group. A perianastomotic abscess was detected on autopsy in one animal from the primary colo-colonic anastomosis group. The bursting pressures of the jejunocolic anastomoses were significantly higher ( P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001) than those of the primary colo-colonic anastomoses. These experimental results suggest that jejunal interposition may be a feasible alternative to primary colonic anastomosis to create intestinal continuity after resection for acute obstruction of the left colon.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Rural patients have poor access to specialists and are less likely to receive evidence-based canc... more Rural patients have poor access to specialists and are less likely to receive evidence-based cancer care. We hypothesized that hepatocellular carcinoma (HCC) patients from rural counties in Texas would be less likely to receive surgical therapy than those from urban areas. The Texas Cancer Registry was queried (2000-2008). County-level data included &amp;amp;quot;rural or urban&amp;amp;quot; designation and income variables derived by zip code. Surgical intervention included: (i) ablation, (ii) resection-partial or total lobectomy, or (iii) transplantation. A multinomial logistic regression was created to determine predictors of intervention. Five thousand thirty seven HCC patients were identified (86% urban) for study. A multinomial regression demonstrated, older age, African-American race, and lower income reduced the likelihood of ablation. Younger age, female gender, Caucasian, and Asian/other race predicted surgical resection, or transplantation. Hispanic race was associated with lower likelihood of resection (RRR 0.75) and transplantation (RRR 0.74), whereas African-American race was associated with pronounced decrease for transplantation (RRR 0.48). Area of residency was not predictive of intervention. Rural residency did not decrease the likelihood of surgical intervention for hepatocellular carcinoma. Race and income continue to be associated with significant treatment disparity. Additional investigation should focus on factors that govern the selection of resection or transplantation for potentially eligible patients.
Biochemical and Biophysical Research Communications, Aug 1, 2002
Ubiquitin-proteasome-dependent protein degradation plays a central role in sepsis-induced muscle ... more Ubiquitin-proteasome-dependent protein degradation plays a central role in sepsis-induced muscle wasting. Because the proteasome degrades proteins into small peptides rather than free amino acids, it is likely that additional mechanisms downstream of the proteasome are involved in sepsis-induced muscle proteolysis. Recent studies suggest that the extralysosomal peptidase tripeptidyl-peptidase II (TPP II) degrades peptides generated by the proteasome. We hypothesized that TPP II expression and activity are increased in skeletal muscle during sepsis. Sepsis was induced in rats by cecal ligation and puncture. Control rats were sham-operated. TPP II activity was determined by using the specific substrate Ala-Ala-Phe-7-amido-4-methylcoumarin (AAF-AMC). TPP II protein and gene expression were determined by Western blot and real-time PCR, respectively. Sepsis resulted in increased activity and protein and gene expression of TPP II in extensor digitorum longus muscles. This result was blunted by the glucocorticoid receptor antagonist RU 38486, indicating that glucocorticoids participate in the upregulation of TPP II in skeletal muscle during sepsis. The results suggest that proteolytic mechanisms downstream of the proteasome may be important for the complete degradation of muscle proteins during sepsis.
INTRODUCTION Emerging data suggests neoadjuvant chemotherapy for resectable pancreatic ductal ade... more INTRODUCTION Emerging data suggests neoadjuvant chemotherapy for resectable pancreatic ductal adenocarcinoma (PDAC) is associated with improved survival. However, less than 40% demonstrate a meaningful radiographic response to NAC. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) has emerged as a new modality to treat PDAC. We hypothesize that NAC plus EUS-RFA can be used in the management of resectable PDAC. METHODS Prospective review of PDAC patients meeting criteria of resectable tumor anatomy that underwent NAC chemotherapy plus EUS-RFA followed by pancreatic resection. Radiographic imaging, perioperative and short-term outcomes were recorded. Surgical pathology specimens were analyzed for treatment response. RESULTS Three eligible patients with resectable PDAC received 4 months of neoadjuvant chemotherapy plus EUS-RFA. One month after completion of neoadjuvant treatment, all 3 patients underwent standard pancreaticoduodenectomy without complications. After a 6 week recovery, all patients completed 2 months of post-op adjuvant chemotherapy. CONCLUSIONS In our institutional experience, this treatment protocol appears safe. Patients tolerated the combination of chemotherapy and endoscopic radiofrequency ablation. Patients underwent pancreatic resection with uneventful recovery. This novel neoadjuvant approach may provide a more effective alternative to chemotherapy alone.
IntroductionIn response to the COVID-19 pandemic, hospitals reported decreased admissions for acu... more IntroductionIn response to the COVID-19 pandemic, hospitals reported decreased admissions for acute surgical diagnoses, but scant data was available to quantify the decrease and its consequences. The objective of this study was to examine the incidence of acute care surgery encounters before and during the COVID-19 pandemic.Materials and MethodsA retrospective cohort study was performed at a single, urban, United States safety-net hospital. Emergency room encounters, admissions, non-elective surgical procedures, patient acuity, and surgical complications were compared before and after the start of the COVID-19 pandemic. The primary outcome of the study was the incidence rate (IR) and incidence rate ratios (IRR) for surgical admissions, laparoscopic appendectomy, and urgent laparoscopic cholecystectomy.ResultsDuring the COVID-19 (exposure) time period, the number of nonelective procedures was 143 (IR 4.76) which was significantly lower than the control periods (n = 431, IR 7.2), P < 0.001. During the COVID-19 exposure period, there were significantly fewer urgent cholecystectomies performed (1.37 per day versus 2.80-2.93 per day, P < 0.001). There was a trend toward fewer appendectomies performed, but not significant. There was little difference in patient acuity between the exposure and control periods. A higher proportion of patients that underwent urgent cholecystectomy during the COVID time period had been seen in the ED in the prior 30 d (22% versus 5.6%).ConclusionsSurgical volume significantly decreased during the COVID-19 pandemic. Management of acute cholecystitis may require re-evaluation as nonsurgical management appears to increase repeat presentations.
bioRxiv (Cold Spring Harbor Laboratory), Jan 10, 2022
Background and Aims: Pancreatic ductal adenocarcinoma (PDAC) is characterized by resistance to th... more Background and Aims: Pancreatic ductal adenocarcinoma (PDAC) is characterized by resistance to therapy. A major contributing factor to therapeutic failure is profound desmoplasia and a well-documented hypoxic tumor microenvironment (TME). In PDAC, several therapeutic approaches, including chemotherapy and radiation alone or combined with immune checkpoint inhibitors, have shown minimal therapeutic success, placing an imperative need for the discovery and application of innovative treatments. Endoscopic ultrasound guided radiofrequency ablation (EUS-RFA) is a promising immunomodulator therapy for PDAC. In this work, we hypothesized RFA promotes local and systemic stromal and immunomodulating effects that can be identified for new combination therapeutic strategies. Methods: To test our hypothesis, a syngeneic PDAC mouse model was performed by symmetrically injecting 100k murine KPC cells in bilateral flanks of C57BL/6 female mice. RFA treatment initiated when tumors reached 200-500 mm 3 and was performed only in the right flank. The left flank tumor (non-RFA contralateral side) was used as a paired control for further analysis. Results: RFA promoted a significant reduction in tumor growth rate 4 days after treatment in RFA treated and non-RFA side contralateral tumors from treated mice when compared to controls. Histological analysis revealed a significant increase in expression of cleaved Caspase3 in RFA treated tumors. In addition, collagen deposition and CD31+ cells were significantly elevated in RFA side and non-RFA contralateral tumors from RFA treated mice. Proteome profiling showed changes in C5a and IL-23 in RFA responsive tumors, indicating a role of RFA in modulating intratumoral inflammatory responses. Conclusions: These data indicate RFA promotes local and systemic anti-tumor responses in a syngeneic mouse model of PDAC implicating RFA treatment for local tumors as well as metastatic disease.
The catabolic response to sepsis, severe injury, and burn is characterized by whole-body protein ... more The catabolic response to sepsis, severe injury, and burn is characterized by whole-body protein loss, mainly reflecting increased breakdown of muscle proteins, in particular myofibrillar proteins. Glucocorticoids and various proinflammatory cytokines are important regulators of muscle proteolysis in stressed patients. There is evidence that breakdown of proteins by the ubiquitin-proteasome pathway plays an important role in muscle cachexia, although other mechanisms may participate, such as calcium- and calpain-dependent release of myofilaments from the sarcomere. Three types of treatments have been used to reduce or prevent the catabolic response to injury and sepsis: 1). nutritional, 2). hormonal, and 3). pharmacologic. With regard to nutrition support, it is generally believed that enteral feeding is superior to parenteral feeding and that early feeding is better than late feeding. Although &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;immune-enhancing&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; enteral nutrition has been shown in several recent studies to improve outcome in critically ill patients, the specific effects of these treatments on the catabolic response in muscle are not known. In addition to nutrition support, various hormones, including insulin, growth hormone, and insulin-like growth factor-1, may blunt the catabolic response in patients with stress. Experimental studies have indicated that other treatments may become available in the future, including cytokine antibodies, calcium antagonists, and induction of heat shock response. Methods to prevent or reduce the catabolic response to stress are important considering the significant clinical consequences of muscle cachexia.
Previous studies suggest that increased ubiquitin-proteasome-dependent protein breakdown in vario... more Previous studies suggest that increased ubiquitin-proteasome-dependent protein breakdown in various muscle-wasting conditions may at least in part be mediated by increased cellular calcium levels. The role of calcium in the regulation of proteasome activity, however, is not well understood. We treated cultured L6 myotubes with the calcium ionophore A23187 or thapsigargin, substances that increase intracellular calcium levels through different mechanisms, and measured proteasome activity by determining the degradation of the fluorogenic substrate LLVY-AMC. Treatment of the myotubes with A23187 or thapsigargin resulted in a dose- and time-dependent increase in proteasome activity. When the myotubes were treated with metabolic inhibitors, results suggested that the A23187- and thapsigargin-induced activation of proteasome activity was at least in part regulated by calmodulin, calcium calmodulin-dependent kinase II, caspases, and calpains. The present observations support a role of calcium in the regulation of proteasome-dependent protein breakdown in skeletal muscle and may explain why muscle wasting was reduced by calcium antagonists in previous studies.
American Journal of Physiology-regulatory Integrative and Comparative Physiology, May 1, 2003
Recent studies suggest that the skeletal muscle may be a significant site of IL-6 production in v... more Recent studies suggest that the skeletal muscle may be a significant site of IL-6 production in various conditions, including exercise, inflammation, hypoperfusion, denervation, and local muscle injury. The mediators and molecular mechanisms regulating muscle IL-6 production are poorly understood. We tested the hypothesis that IL-6 production in muscle cells is regulated by IL-1 and that mitogenactivated protein (MAP) kinase signaling and NF-B activation are involved in IL-1-induced IL-6 production. Cultured C2C12 cells, a mouse skeletal muscle cell line, were treated with different concentrations (0.1-2 ng/ml) of IL-1 in the absence or presence of the p38 MAP kinase inhibitor SB-208350 or the p42/44 inhibitor PD-98059. Protein and gene expression of IL-6 were determined by ELISA and real-time PCR, respectively. NF-B DNA binding activity was determined by electrophoretic mobility shift assay and by transfecting myocytes with a luciferase reporter plasmid containing a promoter construct with multiple repeats of NF-B binding site. Treatment of myotubes with IL-1 resulted in a dose-and time-dependent increase of IL-6 production accompanied by an ϳ25-fold increase in IL-6 mRNA levels. IL-1 stimulated NF-B DNA binding activity and gene activation. SB-208350 and PD-98059 inhibited the increase in IL-6 production induced by IL-1. The present results support the concept that skeletal muscle is an important site of IL-6 production. In addition, the results suggest the IL-1 regulates muscle IL-6 production at least in part by activating the MAP kinase pathway and NF-B. interleukin-6 production; cytokines; mitogen-activated protein kinase; nuclear factor-B
Biochemical and Biophysical Research Communications, 2002
Muscle cachexia induced by sepsis, severe injury, cancer, and a number of other catabolic conditi... more Muscle cachexia induced by sepsis, severe injury, cancer, and a number of other catabolic conditions is mainly caused by increased protein degradation, in particular breakdown of myofibrillar proteins. Ubiquitin-proteasome-dependent proteolysis is the predominant mechanism of muscle protein loss in these conditions, but there is evidence that several other regulatory mechanisms may be important as well. Some of those mechanisms are reviewed in this article and they include pre-, para-, and postproteasomal mechanisms. Among preproteasomal mechanisms, mediators, receptor binding, signaling pathways, activation of transcription factors, and modification of proteins are important. Several paraproteasomal mechanisms may influence the trafficking of ubiquitinated proteins and their interaction with the proteasome, including the expression and activity of the COP9 signalosome, the carboxy terminus of heat shock protein 70-interacting protein (CHIP) and valosin-containing protein (VCP). Finally, because the proteasome does not degrade proteins completely into free amino acids but into peptides, postproteasomal degradation of peptides by the giant protease tripeptidyl peptidase II (TPP II) and various aminopeptidases is important in muscle catabolism. Thus, multiple mechanisms and regulatory steps may influence the breakdown of ubiquitinated muscle proteins by the 26S proteasome.
Background: The extent of lymphadenectomy in colon cancer may impact potential to cure and accura... more Background: The extent of lymphadenectomy in colon cancer may impact potential to cure and accuracy of staging. Methods: The Veterans Affairs Central Cancer Registry database was queried for TNM stage I-III colon adenocarcinoma patients and yielded 5,823 individuals. The number of lymph nodes examined, number positive, and the positive:examined lymph node ratio were studied with respect to overall survival by using log-rank and Kaplan-Meier analysis. Results: The overall survival (OS) in stage II patients was greater with the higher number of lymph node (LN) examined. For stage II patients, the 5-year OS was 34%, 43%, 47%, and 55% for the lowest to highest quartiles (P ϭ .007). For stage III patients, the 5-year OS was 31%, 27%, 38%, and 53% for the lowest to highest quartiles (not significant overall). OS is greater with an increased number of positive lymph nodes (P Ͻ .001). The lymph node ratio was more powerful prognostically with a 5-year OS of 27% for the highest quartile versus 44% for the lowest. Conclusions: More extensive lymphadenectomy is associated with improved OS in stage II colon cancer patients. The positive:examined LN ratio is more powerful prognostically than the number of nodes examined or LN positivity.
American Journal of Physiology-regulatory Integrative and Comparative Physiology, Feb 1, 2002
We examined the influence of sepsis, induced by cecal ligation and puncture in rats, on the prote... more We examined the influence of sepsis, induced by cecal ligation and puncture in rats, on the protein and gene expression and hormone binding activity of the glucocorticoid receptor (GR) in skeletal muscle. Sepsis resulted in increased GR mRNA and protein levels and upregulated hormone binding activity in extensor digitorum longus and soleus muscles. Scatchard analysis suggested that the increased GR hormone binding activity reflected an increased number of hormone binding sites, whereas receptor affinity for glucocorticoids was unchanged. The GR antagonist RU-38486 blocked the sepsis-induced increase in GR expression and hormone binding activity, implicating a positive regulatory effect of glucocorticoids on GR expression and binding activity under the present experimental conditions. The results suggest that glucocorticoid-dependent metabolic changes in skeletal muscle during sepsis may reflect not only high circulating glucocorticoid levels but increased amounts and hormone binding activity of the GR as well.
Background: Prognosis after resection of colorectal liver metastases is influenced by various fac... more Background: Prognosis after resection of colorectal liver metastases is influenced by various factors. A positive margin of resection (MOR) has been shown to adversely influence prognosis. Although a 1-cm MOR has been accepted as adequate, the data to support this guideline are sparse. Methods: Our hepatobiliary database was queried for patients who underwent liver resection for colorectal metastases between January 1992 and July 2003. All patients were divided into three groups: MOR <.5 cm (group A), .5 to 1 cm (group B), and >1 cm (group C). Operative reports from each hepatic resection were analyzed to determine local factors that may have contributed to a subcentimeter MOR. Results: A total of 112 patients (67 men and 45 women) underwent liver resection for colorectal metastases with negative margins. Fifty-three patients were in group A, 26 patients were in group B, and 33 patients were in group C. Group C demonstrated decreased local recurrence (LR; P = .003), distant recurrence (DR; P = .008), and disease-free recurrence (P = .002). A significant difference in the overall time to LR (P = .003), time to DR (P = .003), and disease-free survival (P = .002) was also demonstrated. Factors associated with a subcentimeter MOR included nonanatomical resection (P = .043), proximity to a major vessel (P = .003), and central location (P = .002). Conclusions: A <1-cm resection for colorectal liver metastases is associated with increased LR and DR, as well as decreased disease-free survival. When a nonanatomical resection is performed, a MOR >1 cm should be attempted, because an adequate margin is often underestimated. Considerations should be made for extended resections when tumors are centrally located or near major vessels.
American Journal of Physiology-regulatory Integrative and Comparative Physiology, Feb 1, 2002
Sepsis-induced muscle cachexia is associated with increased expression of several genes in the ub... more Sepsis-induced muscle cachexia is associated with increased expression of several genes in the ubiquitin-proteasome proteolytic pathway, but little is known about the activation of transcription factors in skeletal muscle during sepsis. We tested the hypothesis that sepsis upregulates the expression and activity of the transcription factors CCAAT/ enhancer binding protein (C/EBP)- and-␦ in skeletal muscle. Sepsis was induced in rats by cecal ligation and puncture, and control rats were sham operated. C/EBP- and-␦ DNAbinding activity was determined by electrophoretic mobility shift assay and supershift analysis. In addition, C/EBP- and-␦ nuclear protein levels were determined by Western blot analysis. Sepsis resulted in increased DNA-binding activity of C/EBP, and supershift analysis suggested that this reflected activation of the and ␦-isoforms of C/EBP. Concomitantly, C/EBP- and-␦ protein levels were increased in the nuclear fraction of skeletal muscle. In additional experiments, we tested the role of glucocorticoids in sepsis-induced activation of C/EBP- and-␦ by treating rats with the glucocorticoid receptor antagonist RU-38486. This treatment inhibited the sepsis-induced activation of C/EBP- and-␦, suggesting that glucocorticoids participate in the upregulation of C/EBP in skeletal muscle during sepsis. The present results suggest that C/EBP- and-␦ are activated in skeletal muscle during sepsis and that this response is, at least in part, regulated by glucocorticoids. transcription factors; cachexia; proteolysis; ubiquitin; proteasome; CCAAT/enhancer binding protein; deoxyribonucleic acid MUSCLE CACHEXIA during sepsis and various other catabolic conditions, including cancer, burn injury, starvation, and uremia, mainly reflects increased ubiquitinproteasome-dependent protein degradation (10). Muscle wasting in these conditions is associated with increased expression of several genes in the ubiquitinproteasome proteolytic pathway (25, 26
Background. In previous studies, dantrolene prevented sepsis-induced muscle proteolysis, but the ... more Background. In previous studies, dantrolene prevented sepsis-induced muscle proteolysis, but the influence of dantrolene on the expression and activity of the ubiquitin-proteasome proteolytic pathway is not known. In addition, the role of glucocorticoids in the anabolic effect of dantrolene is not well understood. Methods. Sepsis was induced in rats by cecal ligation and puncture (CLP). Other rats underwent shamoperation. Groups of rats were treated with dantrolene (10 mg/kg) administered 2 h before and 8 h after sham-operation or CLP. Sixteen hours after sham-operation or CLP, mRNA levels for ubiquitin, the ubiquitin ligase E3␣, and the 20S proteasome subunit C3 were determined by dot-blot analysis. In additional experiments, the effect of dantrolene on protein degradation was tested in L6 myotubes cultured in the absence or presence of dexamethasone. Results. Treatment of rats with dantrolene prevented the sepsis-induced increase in mRNA levels for ubiquitin, the ubiquitin ligase E3␣, and the 20S proteasome subunit C3. In additional experiments, treatment of cultured myotubes with dantrolene reduced protein degradation in both the absence and the presence of dexamethasone. Conclusions. The results suggest that dantrolene can prevent sepsis-induced activation of the ubiquitinproteasome proteolytic pathway in skeletal muscle and that dantrolene reduces muscle protein degradation independent of glucocorticoids.
Biochemical and Biophysical Research Communications, Mar 1, 2001
Sepsis is associated with increased muscle proteolysis and upregulated transcription of several g... more Sepsis is associated with increased muscle proteolysis and upregulated transcription of several genes in the ubiquitin-proteasome proteolytic pathway. Glucocorticoids are the most important mediator of sepsis-induced muscle cachexia. Here, we examined the influence of sepsis in rats on the transcription factors NF-B and AP-1 in skeletal muscle and the potential role of glucocorticoids in the regulation of these transcription factors. Sepsis was induced by cecal ligation and puncture (CLP). Control rats were sham-operated. NF-B and AP-1 DNA binding activity was determined by electrophoretic mobility shift assay (EMSA) in extensor digitorum longus muscles at different time points up to 16 h after sham-operation or CLP. Sepsis resulted in an early (4 h) upregulation of NF-B activity followed by inhibited NF-B activity at 16 h. AP-1 binding activity was increased at all time points studied during the septic course. When rats were treated with the glucocorticoid receptor antagonist RU38486, NF-B activity increased, whereas AP-1 activity was not influenced by RU38486. The results suggest that NF-B and AP-1 are differentially regulated in skeletal muscle during sepsis and that glucocorticoids may regulate some but not all transcription factors in septic muscle.
Much debate surrounds the one-stage surgical management of acute left colon obstruction. Many sur... more Much debate surrounds the one-stage surgical management of acute left colon obstruction. Many surgeons are still reluctant to perform primary anastomosis in unprepared bowel fearing the risk of anastomotic dehiscence. Although intraoperative lavage and subtotal colectomy have recently proved effective for preventing fecal loading, both of these procedures have drawbacks and the search for additional alternative surgical procedures continues. We conducted an experimental study to examine a new one-stage operation, consisting of the interposition of a jejunal segment to the resection site of the colon, to manage acute left colon obstruction. The colons of 20 domestic pigs were obstructed, and 2 days later, segmental resection and either primary colo-colonic anastomosis or interposition of a jejunal segment was performed. Autopsies were done 6 weeks after the operations and the anastomotic regions were subjected to bursting pressure analysis. The operating time was longer in the interposition group at 49 +/- 14 vs 38 +/- 12 min ( P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). There was no mortality or clinical signs of anastomotic dehiscence in either group. A perianastomotic abscess was detected on autopsy in one animal from the primary colo-colonic anastomosis group. The bursting pressures of the jejunocolic anastomoses were significantly higher ( P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001) than those of the primary colo-colonic anastomoses. These experimental results suggest that jejunal interposition may be a feasible alternative to primary colonic anastomosis to create intestinal continuity after resection for acute obstruction of the left colon.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Rural patients have poor access to specialists and are less likely to receive evidence-based canc... more Rural patients have poor access to specialists and are less likely to receive evidence-based cancer care. We hypothesized that hepatocellular carcinoma (HCC) patients from rural counties in Texas would be less likely to receive surgical therapy than those from urban areas. The Texas Cancer Registry was queried (2000-2008). County-level data included &amp;amp;quot;rural or urban&amp;amp;quot; designation and income variables derived by zip code. Surgical intervention included: (i) ablation, (ii) resection-partial or total lobectomy, or (iii) transplantation. A multinomial logistic regression was created to determine predictors of intervention. Five thousand thirty seven HCC patients were identified (86% urban) for study. A multinomial regression demonstrated, older age, African-American race, and lower income reduced the likelihood of ablation. Younger age, female gender, Caucasian, and Asian/other race predicted surgical resection, or transplantation. Hispanic race was associated with lower likelihood of resection (RRR 0.75) and transplantation (RRR 0.74), whereas African-American race was associated with pronounced decrease for transplantation (RRR 0.48). Area of residency was not predictive of intervention. Rural residency did not decrease the likelihood of surgical intervention for hepatocellular carcinoma. Race and income continue to be associated with significant treatment disparity. Additional investigation should focus on factors that govern the selection of resection or transplantation for potentially eligible patients.
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