Papers by Mark Joshua Jimenez
Biology of Reproduction, 2005
Sensitive and specific measurement of FSH is critical to research in reproductive biology, and th... more Sensitive and specific measurement of FSH is critical to research in reproductive biology, and the increasing availability of transgenic mouse models has created a need for a robust, sensitive, and specific mouse (m) FSH assay. The present study evaluated a time-resolved immunofluorometric assay (IFMA) for mFSH using monoclonal antibody to human (h) FSH as a capture antibody and a biotinylated polyclonal antibody to rat ␣ subunit as a detection probe, with signaling amplified by europium-labeled streptavidin. The mFSH IFMA lowered the detection limit 34-fold (5 vs. 170 pg/sample) compared with standard mFSH RIA. The mFSH IFMA demonstrated parallelism of response to dilutions of castrated mouse serum and rat FSH but no cross-reactivity with hFSH and mLH or hLH, whereas the RIA demonstrated nonparallel cross-reactivity with hFSH. The IFMA has a wide analytical range, with a good precision profile for within-and between-assay reproducibility. Because the IFMA is a sandwich-type assay with strict dimer-specificity by design, the lower readings and recovery obtained were compared with the RIA when both assays used a pituitary-purified mFSH assay standard that contained isolated or fragmented subunits as well as intact dimeric FSH. When used with mouse serum sample, the mFSH IFMA demonstrated the expected increases following orchidectomy as well as markedly enhanced sensitivity to very low levels of endogenous mFSH in gonadotropin-deficient mice. Furthermore, the IFMA measured mFSH with fidelity in both intact and orchidectomized male mice without any interference from transgenic hFSH. The greatly enhanced sensitivity, specificity, and technical convenience of this mFSH IFMA will allow wider application of FSH measurements to very small blood samples in immature and mature mice as well as transgenic models.
Journal of Endocrinology, May 15, 2013
Neurturin (NTN) is a member of the glial cell line-derived neurotrophic factor (GDNF) family and ... more Neurturin (NTN) is a member of the glial cell line-derived neurotrophic factor (GDNF) family and signals through GDNF family receptor alpha 2 (GFRa2). We hypothesised that epithelial atrophy reported in the reproductive organs of Ntn (Nrtn)-and Gfra2 (Gfra2)-deficient mice could be due to NTN affecting the hormonal environment. To investigate this, we compared the reproductive organs of Ntn-and Gfra2-deficient male mice in parallel with an analysis of their circulating reproductive hormone levels. There were no significant structural changes within the organs of the knockout mice; however, serum and intratesticular testosterone and serum LH levels were very low. To reconcile these observations, we tested androgen sensitivity by creating a dihydrotestosterone (DHT) clamp (castration plus DHT implant) to create fixed circulating levels of androgens, allowing the evaluation of androgen-sensitive endpoints. At the same serum DHT levels, serum LH levels were lower and prostate and seminal vesicle weights were higher in the Ntn knockout (NTNKO) mice than in the wild-type mice, suggesting an increased response to androgens in the accessory glands and hypothalamus and pituitary of the NTNKO mice. Testicular and pituitary responsiveness was unaffected in the NTNKO males, as determined by the response to the human chorionic gonadotrophin or GNRH analogue, leuprolide, respectively. In conclusion, our results suggest that NTN inactivation enhances androgen sensitivity in reproductive and neuroendocrine tissues, revealing a novel mechanism to influence reproductive function and the activity of other androgen-dependent tissues. Key Words " glial cell line-derived neurotrophic factor (GDNF) family " TGFb family " neurotrophic " hypothalamic-pituitarytesticular axis " urogenital tract
American Journal of Physiology-endocrinology and Metabolism, Oct 1, 2011
Archives of Disease in Childhood, Oct 1, 1991
Nocturnal growth hormone secretion over a 12 hour period was assessed at 20 minute intervals in 2... more Nocturnal growth hormone secretion over a 12 hour period was assessed at 20 minute intervals in 25 prepubertal subjects with Turner's syndrome and 11 normal prepubertal girls of short stature to try and elucidate the relationship between body weight and endogenous secretion of growth hormone in Turner's syndrome. There were no differences in mean growth hormone concentration, age, height, or growth velocity between the two groups.
Reproduction, Fertility and Development, 2017
Androgens synergise with FSH in female reproduction but the nature of their interaction in ovaria... more Androgens synergise with FSH in female reproduction but the nature of their interaction in ovarian function and fertility is not clear. In the present study, we investigated this interaction, notably whether higher endogenous FSH can overcome defective androgen actions in androgen receptor (AR)-knockout (ARKO) mice. We generated and investigated the reproductive function of mutant mice exhibiting AR resistance with or without expression of human transgenic FSH (Tg-FSH). On the background of inactivated AR signalling, which alone resulted in irregular oestrous cycles and reduced pups per litter, ovulation rates and antral follicle health, Tg-FSH expression restored follicle health, ovulation rates and litter size to wild-type levels. However, Tg-FSH was only able to partially rectify the abnormal oestrous cycles observed in ARKO females. Hence, elevated endogenous FSH rescued the intraovarian defects, and partially rescued the extraovarian defects due to androgen insensitivity. In addition, the observed increase in litter size in Tg-FSH females was not observed in the presence of AR signalling inactivation. In summary, the findings of the present study reveal that FSH can rescue impaired female fertility and ovarian function due to androgen insensitivity in female ARKO mice by maintaining follicle health and ovulation rates, and thereby optimal female fertility.
Endocrinology, 2015
Accurate measurement of testosterone is important for reproductive endocrinology research, but th... more Accurate measurement of testosterone is important for reproductive endocrinology research, but the validity of direct (nonextraction) testosterone immunoassays, developed and validated for human serum, has not been appraised for application to mouse serum or steroidogenic tissue extracts. Testosterone was measured in serum and extracts of testis or ovary from male and female wild-type mice by 2 commercial direct testosterone immunoassays, with and without preassay extraction, and by the liquid chromatography, tandem mass spectrometry reference method. Results were compared hierarchically by correlation (Kendall's), regression (Passing-Bablok), and deviance (Bland-Altman) analysis, under the null hypothesis of perfect agreement between assays (slope ϭ 1, intercept and deviation ϭ 0). For mouse serum, immunoassays displayed an upward bias with performance better for male vs female sera and, within gender, improved by preassay extraction relative to liquid chromatography, tandem mass spectrometry. Testosterone was detectable in all serum samples, but few (male 54%, female 9%) were accurate (within 20% of the reference measurement). For mouse testis extracts, immunoassays were biased upwards, and preassay extraction improved immunoassay performance. Although testosterone was detectable in all extracts, a minority (45%) was accurate. For mouse ovary extracts, all correlations were poor with severe, upward bias, and while testosterone was detectable in all samples, virtually none were accurate. We conclude that these direct testosterone immunoassay kits provide relatively, but not absolutely, accurate results with male mouse serum and testis extracts but not with female mouse serum and ovary extracts, with performance improved by preassay extraction. Whether relative accuracy is fit for purpose depends on the experimental aims, design, and interpretation.
Journal of Endocrinology, Mar 1, 2006
Ovarian primordial follicle reserve is considered hormonally independent or subject to depletion ... more Ovarian primordial follicle reserve is considered hormonally independent or subject to depletion by FSHdriven follicle recruitment. To explore specific in vivo effects of FSH on early follicle populations in the absence of luteinizing hormone (LH) activity, we examined mature hypogonadal (hpg), gonadotrophin-deficient mice expressing transgenic (tg) human FSH. Sustained expression of tg-FSH (5•3 0•3 IU/l) increased ovary weights fourfold and significantly elevated total primordial follicle numbers twofold in tg-FSH hpg (4209 457) relative to non-tg hpg (2079 391) and wild-type (2043 195) age-matched ovaries. Absolute primary follicle numbers in tg-FSH hpg ovaries were similar to non-tg hpg and wild-type ovaries. Furthermore, tg-FSH quantitatively increased secondary and antral follicles in hpg ovaries to numbers equivalent to wild-type, but did not induce ovulation, indicating a selective FSH response without LH. Circulating inhibin B and inhibin A levels were significantly increased in tg-FSH hpg females compared with hpg controls, and inhibin B correlated with antral number, consistent with FSH-driven antral follicle formation. These findings revealed that sustained pituitaryindependent FSH activity, in the absence of endogenous gonadotrophins, promotes an increase in primordial follicle reserve despite also stimulating follicular growth in mature females. Therefore, the tg-FSH hpg ovary presents a novel paradigm to evaluate specific gonadotrophin effects on follicle reserve and recruitment.
Biology of Reproduction, 2004
Testosterone (T) is an absolute requirement for spermatogenesis and is supplied by mature Leydig ... more Testosterone (T) is an absolute requirement for spermatogenesis and is supplied by mature Leydig cells stimulated by LH. We previously showed in gonadotropin-deficient hpg mice that T alone initiates qualitatively complete spermatogenesis bypassing LH-dependent Leydig cell maturation and steroidogenesis. However, because maximal T effects do not restore testis weight or germ cell number to wild-type control levels, additional Leydig cell factors may be involved. We therefore examined 1) whether chronic hCG administration to restore Leydig cell maturation and steroidogenesis can restore quantitatively normal spermatogenesis and testis development and 2) whether nonandrogenic Leydig cell products are required to initiate spermatogenesis. Weanling hpg mice were administered hCG (0.1-100 IU i.p. injection three times weekly) or T (1-cm subdermal Silastic implant) for 6 weeks, after which stereological estimates of germinal cell populations, serum and testicular T content, and testis weight were evaluated. Human CG stimulated Leydig cell maturation and normalized testicular T content compared with T treatment where Leydig cells remained immature and inactive. The maximal hCG-induced increases in testis weight and serum T concentrations were similar to those for T treatment and produced complete spermatogenesis characterized by mature, basally located Sertoli cells (SCs) with tripartite nucleoli, condensed haploid sperm, and lumen development. Compared with T treatment, hCG increased spermatogonial numbers, but both hCG and T had similar effects on numbers of spermatocytes and round and elongated spermatids per testis as well as per SC. Nevertheless, testis weight and germ cell numbers per testis and per SC remained well below phenotypically normal controls, confirming the involvement of non-Leydig cell factors such as FSH for quantitative normalization of spermatogenesis. We conclude that hCG stimulation of Leydig cell maturation and steroidogenesis is not required, and that T alone mostly replicates the effects of hCG, to initiate spermatogenesis. Because T is both necessary and sufficient for initiation of spermatogenesis, it is likely that T is the main Leydig cell secretory product involved and that additional LH-dependent Leydig cell factors are not essential for induction of murine spermatogenesis.
Endocrinology, Apr 9, 2009
Female androgen receptor (AR) knockout mice (AR Ϫ/Ϫ) generated by an in-frame Ar exon 3 deletion ... more Female androgen receptor (AR) knockout mice (AR Ϫ/Ϫ) generated by an in-frame Ar exon 3 deletion are subfertile, but the mechanism is not clearly defined. To distinguish between extra-and intraovarian defects, reciprocal ovarian transplants were undertaken. Ovariectomized AR Ϫ/Ϫ hosts with wild-type (AR ϩ/ϩ) ovary transplants displayed abnormal estrus cycles, with longer cycles (50%, P Ͻ 0.05), and 66% were infertile (P Ͻ 0.05), whereas AR ϩ/ϩ hosts with either AR Ϫ/Ϫ or surgical control AR ϩ/ϩ ovary transplants displayed normal estrus cycles and fertility. These data imply a neuroendocrine defect, which is further supported by increased FSH (P Ͻ0.05) and estradiol (P Ͻ0.05) , and greater LH suppressibility by estradiol in AR Ϫ/Ϫ females at estrus (P Ͻ0.05). Additional intraovarian defects were observed by the finding that both experimental transplant groups exhibited significantly reduced pups per litter (P Ͻ 0.05) and corpora lutea numbers (P Ͻ 0.05) compared with surgical controls. All groups exhibited normal uterine and lactation functions. AR Ϫ/Ϫ uteri were morphologically different from AR ϩ/ϩ with an increase in horn length (P Ͻ 0.01) but a reduction in uterine diameter (P Ͻ 0.05), total uterine area (P Ͻ 0.05), endometrial area (P Ͻ 0.05), and myometrial area (P Ͻ 0.01) at diestrus, indicating a role for AR in uterine growth and development. Both experimental transplant groups displayed a significant reduction in uterine diameter (P Ͻ 0.01) compared with transplanted wild-type controls, indicating a role for both AR-mediated intraovarian and intrauterine influences on uterine physiology. In conclusion, these data provide direct evidence that extraovarian neuroendocrine, but not uterine effects, as well as local intraovarian AR-mediated actions are important in maintaining female fertility, and a disruption of AR signaling leads to altered uterine development.
The Journal of Steroid Biochemistry and Molecular Biology, Aug 1, 2010
Accurate measurement of sex steroids is essential to evaluate mouse models for human reproductive... more Accurate measurement of sex steroids is essential to evaluate mouse models for human reproductive development and disorders. The recent advent of liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays that match the sensitivity of steroid immunoassay could overcome problems arising from the limited specificity of steroid immunoassay. In this current study we validate a LC-MS/MS assay for the measurement of key sex steroids from murine serum and reproductive tissues. The assay gave excellent dilutional linearity (r 2 ≥ 0.98) and reproducibility (CV ≤ 10% of replicate samples) in serum and reproductive tissues with sensitive quantitation limits; testosterone (T; 2 pg), dihydrotestosterone (DHT; 10 pg), 5␣-androstane-3␣,17-diol (3␣Diol; 40 pg), 5␣-androstane-3,17-diol (3Diol; 40 pg), estradiol (E2; 0.5 pg) and estrone (E1; 0.3 pg). Using 0.1 mL sample, T was the only consistently detectable steroid (detection limit 20 pg/ml) in both male and female mouse serum. In the testis, T and DHT were quantifiable as were both diols at relatively high levels. Prostatic T levels were low and DHT was determined to be the most abundant androgen in this tissue. Uterine and ovarian levels of E2, E1 and T were measurable, with levels varying according to estrous cycle stage. Hence, we demonstrate that this LC-MS/MS method has the sensitivity, specificity and multi-analyte capability to offer accurate steroid profiling in mouse serum and reproductive tissues.
Proceedings of the National Academy of Sciences of the United States of America, Mar 20, 2017
The Journal of Clinical Endocrinology and Metabolism, Aug 1, 2003
Androgen therapy may precipitate obstructive sleep apnea in men. Despite increasing androgen use ... more Androgen therapy may precipitate obstructive sleep apnea in men. Despite increasing androgen use in older men, few studies have examined sleep and breathing. Randomized, doubleblind, placebo-controlled studies examining effects of testosterone simultaneously on sleep, breathing, and function in older men are not available. Seventeen community-dwelling healthy men over the age of 60 yr were randomized to receive three injections of im testosterone esters at weekly intervals (500 mg, 250 mg, and 250 mg) or matching oil-based placebo and then crossed over to the other treatment after 8 wk of washout. Polysomnography, anthropometry, and physical, mental, and metabolic function were assessed at baseline and after each treatment period. Testosterone treatment reduced total time slept (ϳ1 h), increased the duration of hypoxemia (ϳ5 min/night), and disrupted breathing during sleep (total and non-rapid eye movement respiratory disturbance indices both increased by approximately seven events per hour) (all P < 0.05). Despite expected effects on body composition (increase in total and lean mass, reduction in fat mass, P < 0.05, bioimpedance method), upper airway dimensions did not change (acoustic reflectometry). Driving ability (computer simulation), physical activity (accelerometry, Physical Activity Scale in the Elderly), quality of life (SF36, Functional Outcomes of Sleep Questionnaire), mood (Profile of Mood States Questionnaire), sleepiness (Epworth, Stanford scales), and insulin resistance (homeostasis model) also were not changed by treatment. Short-term administration of high-dose testosterone shortens sleep and worsens sleep apnea in older men but did not alter physical, mental, or metabolic function. These changes did not appear to be due to upper airway narrowing. Further study of longer-term lower-dose androgen therapy on sleep and breathing is needed to evaluate its safety in older men.
Progresos de Obstetricia y Ginecología, 2004
Objective: To determine the hysterectomy rate, demographic characteristics, diagnoses and procedu... more Objective: To determine the hysterectomy rate, demographic characteristics, diagnoses and procedures used, based on data registered in the Andalusian Minimum Data Set. Material and methods: We compared diagnoses and procedures in hysterectomies with and without bilateral annexectomy performed in 33 public hospitals of the Autonomous Community of Andalusia in 2000. Results: A total of 5,628 hysterectomies were performed. Of these, 2,728 were performed without bilateral annexectomy and 2,846 with bilateral annexectomy. Hysterectomies with bilateral annexectomy were more frequent among women aged 40-50 years old and those without were more frequent among women aged 35-39 years and 60-70 years. The general hysterectomy rate was estimated at 152 hysterectomies per 100,000 women or 200 hysterectomies per 100,000 women aged more than 20 years old. The highest hysterectomy rate corresponded to women aged 45-50 years (600 hysterectomies per 100,000 women). Rates differed among provinces and hospitals. Seventeen percent of hysterectomies were performed for malignancies and the remainder was performed for benign processes (56% for leiomyoma and 24% for genital prolapse). Total abdominal hysterectomy was used in 65% of the procedures and laparoscopy-assisted vaginal hysterectomy was used in 1.6%. Conclusions: More than half the hysterectomies for benign processes were performed in perimenopausal women with a diagnosis of leiomyoma and were associated with bilateral annexectomy, with variation among hospitals. In future, periodic review of the hysterectomy rate will allow us to evaluate the effectiveness of new techniques such as hysteroscopy and local hormone replacement therapy in reducing the this type of surgery.
Pediatric Research, Mar 1, 1996
Reproduction, Fertility and Development, 2008
Spermatogenesis requires androgen but, paradoxically, oestradiol (E2) treatment stimulates sperma... more Spermatogenesis requires androgen but, paradoxically, oestradiol (E2) treatment stimulates spermatogenic development in gonadotrophin-and androgen-deficient hypogonadal (hpg) mice. The mechanisms of E2-induced spermatogenesis were investigated by determining intratesticular E2 levels and testis cell populations in E2-treated hpg male mice, and E2 spermatogenic actions were determined in androgen receptor-knockout (ARKO) mice. Despite increased serum E2 concentrations (150-300 pmol L −1), intratesticular E2 concentrations declined fivefold (P < 0.001) in E2-treated v. untreated hpg male mice. Serum FSH reached 40% of normal and total testicular numbers of known FSHresponsive Sertoli, spermatogonia and meiotic spermatocyte populations were significantly (P < 0.001) elevated 1.7-, 4and 13-fold, respectively. However, E2 administration also increased androgen-dependent pachytene spermatocytes and post-meiotic spermatids to levels comparable with testosterone-treated hpg testes. Selective investigation of androgen receptor involvement used E2-treated ARKO mice, which were found to exhibit increased (1.6-fold; P < 0.05) intratesticular E2 concentrations and suppression of the elevated serum gonadotrophins, although FSH remained twofold higher than normal. However, testis size and total Sertoli, spermatogonia and spermatocyte numbers were not increased in E2-treated ARKO male mice. Therefore, E2-stimulated murine spermatogenic development occurs with markedly suppressed and not elevated intratesticular E2 levels and displays an absolute requirement for functional androgen receptors. We propose that this paradoxical E2 spermatogenic response is explained by predominantly extratesticular E2 actions, increasing FSH to combine with residual androgen activity in hpg testes to stimulate pre-to post-meiotic development.
The New England Journal of Medicine, Jul 20, 1989
To determine the timing of pubertal development and the frequency of gonadal dysfunction in child... more To determine the timing of pubertal development and the frequency of gonadal dysfunction in children who survive acute lymphoblastic leukemia, we assessed pubertal status and the plasma levels of sex steroids, gonadotropin, and inhibin in 45 children (20 girls and 25 boys) who had received combination chemotherapy along with 24 Gy of irradiation to the cranium (modified LSA2L2 protocol). We also reexamined testicular biopsy specimens, obtained at the time of the cessation of chemotherapy, for the presence of germ cells. Germ-cell damage, indicated by marked elevations in the plasma level of follicle-stimulating hormone (P less than 0.001 for the comparison with normal children), was evident in both sexes and was confirmed in the boys by the absence of germ cells in the testicular biopsy specimens and by the small size of the testes for pubic-hair stage. Only 44 percent of the pubertal girls had measurable plasma inhibin levels, as compared with more than 93 percent of normal pubertal girls. Although plasma sex-steroid levels were normal, the secretion of luteinizing hormone in response to stimulation with gonadotropin-releasing hormone was elevated in the pubertal children (P less than 0.01 for the comparison with normal controls)--a finding that suggests compensation for decreased gonadal function. Despite clear evidence of gonadal damage, girls had early menarche at a mean age (+/- SD) of 11.95 +/- 0.91 years, as compared with the Australian standard of 12.98 +/- 1.11 years (P less than 0.01). Thus, in girls, puberty was early despite primary gonadal damage. Thirteen of 23 boys reached puberty at a mean age of 12.36 +/- 0.73 years. We conclude that treatment for acute lymphoblastic leukemia may lead to primary gonadal damage in both sexes, regardless of the age at treatment, but that the secondary characteristics of puberty develop at a normal age or, in girls, relatively early.
Endocrinology, Aug 1, 2014
Polycystic ovary syndrome (PCOS) affects 5-10% of women of reproductive age, causing a range of r... more Polycystic ovary syndrome (PCOS) affects 5-10% of women of reproductive age, causing a range of reproductive, metabolic and endocrine defects including anovulation, infertility, hyperandrogenism, obesity, hyperinsulinism, and an increased risk of type 2 diabetes and cardiovascular disease. Hyperandrogenism is the most consistent feature of PCOS, but its etiology remains unknown, and ethical and logistic constraints limit definitive experimentation in humans to determine mechanisms involved. In this study, we provide the first comprehensive characterization of reproductive, endocrine, and metabolic PCOS traits in 4 distinct murine models of hyperandrogenism, comprising prenatal dihydrotestosterone (DHT, potent nonaromatizable androgen) treatment during days 16-18 of gestation, or long-term treatment (90 days from 21 days of age) with DHT, dehydroepiandrosterone (DHEA), or letrozole (aromatase inhibitor). Prenatal DHT-treated mature mice exhibited irregular estrous cycles, oligo-ovulation, reduced preantral follicle health, hepatic steatosis, and adipocyte hypertrophy, but lacked overall changes in body-fat composition. Long-term DHT treatment induced polycystic ovaries displaying unhealthy antral follicles (degenerate oocyte and/or Ͼ 10% pyknotic granulosa cells), as well as anovulation and acyclicity in mature (16-week-old) females. Long-term DHT also increased body and fat pad weights and induced adipocyte hypertrophy and hypercholesterolemia. Long-term letrozole-treated mice exhibited absent or irregular cycles, oligo-ovulation, polycystic ovaries containing hemorrhagic cysts atypical of PCOS, and displayed no metabolic features of PCOS. Long-term dehydroepiandrosterone treatment produced no PCOS features in mature mice. Our findings reveal that long-term DHT treatment replicated a breadth of ovarian, endocrine, and metabolic features of human PCOS and provides the best mouse model for experimental studies of PCOS pathogenesis. (Endocrinology 155: 3146-3159, 2014) P olycystic ovary syndrome (PCOS) affects 5-10% of women of reproductive age (1). It is a complex, heterogeneous disorder with reproductive, endocrine, metabolic, and psychological features. Various clinical definitions are used to define PCOS, and, in general, women must have at least 2 of the following: ovulatory disturbance (or dysfunction), hyperandrogenism, and polycystic ovaries (1, 2). Apart from these hallmark features, PCOS is also characterized by reproductive hormone dys-regulation involving LH hypersecretion and hyperandrogenism leading to acne and hirsutism, reduced fertility, due to dysfunctional follicular maturation, ovulatory disturbance, and miscarriage (3, 4). Nonreproductive metabolic abnormalities are also often present in women with PCOS, including obesity, metabolic syndrome, hyperinsulinemia, insulin resistance, dyslipidemia, and an increased risk of cardiovascular disease and type 2 diabetes (1, 4). Yet, despite its prevalence and health impact, the
Reports of Practical Oncology & Radiotherapy, Jun 1, 2013
Background. Minimizing the volume is critical to adequately treat thoracic injuries. In order to ... more Background. Minimizing the volume is critical to adequately treat thoracic injuries. In order to achieve this, SBRT methods are applied to control physiological movements-such as breathing. We designed and patented a modular system-"eXaCradle"that enables the application of high precision SBRT by controlling position and movements of organs & tumors. The objective. Show our SBRT procedure, that we've called 2i-SBRT. This procedure combines: • Modular system that combines eight points of compression to produce a really customized & efficient treatment base-eXaCradle. • CT-CT and MRI fusion simulation while applying to the patient the customized compression scheme with eXaCradle. • Elekta IGRT and a new quasionline adaptative method based on electronic density differences between slow simulation CT and ConeBeam. We achieve very short treatment times with VMAT techniques. Methods. We work with eXaCradle that gives us an enormous quantity of degrees of freedom to customize the compression of every patient, to every tumor. The following procedure is followed: (a) A Slow-CT of the patient inside the eXaCradle is acquired without any type of compression and in free breathing. (b) On the movement blurring and following the manufacturer's recommendations, the most appropriate combination of compressions is decided. (c) A new Slow-CT* is acquired while applying the compression scheme. (d) A third CT is acquired with breathing held. (e) Organs at risk and tumor must be contoured on the third CT. (f) The third CT and the Slow-CT* are fused. Around the tumor, its movement blurring will be clearly visible. This is the ITV. (g) We design treatment on the Slow-CT*. (h) In the ConeBeamCT the tumor blurring must not exceed the PTV. (i) Patient is treated on Elekta-Synergy linac. (j) After every treatment we repeat the acquisition IGRT and check the modifications during treatment. Conclusions. eXaCradle and ConeBeamCT form a precise and rapid SBRT system. It's a secure technology for the patient and the application of stereotactic therapies.
The Journal of Clinical Endocrinology and Metabolism, Jul 1, 2014
Context: Testosterone (T) and nandrolone (N) esters require deep im injections by medical personn... more Context: Testosterone (T) and nandrolone (N) esters require deep im injections by medical personnel but these often deposit injectate into sc fat so that more convenient sc self-administration may be feasible. Objective: To investigate the feasibility and pharmacology of sc injection of N decanoate in healthy men using dried blood spot (DBS) for frequent blood sampling without clinic visits. Setting and Design: Healthy male volunteers received 100 mg N decanoate by a single sc injection. Finger-prick capillary blood was spotted onto filter paper before injection daily at home for 21 d and stored at room temperature. Venous whole blood was also spotted onto filter paper before and weekly for 3 wk after injection. DBS were extracted for assay of N and T by liquid chromatography tandem mass spectrometry in a single batch with serum concentrations estimated with adjustment for capillary blood sample volume and hematocrit to define peak (N) or nadir (T) time and concentration from individual daily measurements. Results: Daily serum N peaked 2.50 Ϯ 0.25 (SEM) ng/mL at a median (range) of 6 (4-13) days causing a reduction in serum T from 3.50 Ϯ 0.57 ng/mL at baseline to a nadir of 0.38 Ϯ 0.13 (SEM) ng/mL (89 Ϯ 3% suppression) at a median (range) of 8 (5-16) days. Simultaneously sampled capillary, venous whole blood, and serum gave almost identical results for serum T and N. Finger-pricks and sc injections were well tolerated. Conclusions: This study demonstrates that A) DBS sampling with liquid chromatography mass spectrometry steroid analysis achieves frequent time sampling in the community without requiring clinic visits, venesection, or frozen serum storage, and B) androgen esters in an oil vehicle can be delivered effectively by sc injection, thus avoiding the need for medically supervised deep-im injections.
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Papers by Mark Joshua Jimenez