Faculty of Health Sciences

AimSpontaneous activity of embryonic cardiomyocytes originates from sarcoplasmic reticulum (SR) Ca2+ release during early cardiogenesis. However, the regulation of heart rate during embryonic development is still not clear. The aim of this study was to determine how endothelin-1 (ET-1) affects the heart rate of embryonic mice, as well as the pathway through which it exerts its effects.Spontaneous activity of embryonic cardiomyocytes originates from sarcoplasmic reticulum (SR) Ca2+ release during early cardiogenesis. However, the regulation of heart rate during embryonic development is still not clear. The aim of this study was to determine how endothelin-1 (ET-1) affects the heart rate of embryonic mice, as well as the pathway through which it exerts its effects.MethodsThe effects of ET-1 and ET-1 receptor inhibition on cardiac contraction were studied using confocal Ca2+ imaging of isolated mouse embryonic ventricular cardiomyocytes and ultrasonographic examination of embryonic cardiac contractions in utero. In addition, the amount of ET-1 peptide and ET receptor a (ETa) and b (ETb) mRNA levels were measured during different stages of development of the cardiac muscle.The effects of ET-1 and ET-1 receptor inhibition on cardiac contraction were studied using confocal Ca2+ imaging of isolated mouse embryonic ventricular cardiomyocytes and ultrasonographic examination of embryonic cardiac contractions in utero. In addition, the amount of ET-1 peptide and ET receptor a (ETa) and b (ETb) mRNA levels were measured during different stages of development of the cardiac muscle.ResultsHigh ET-1 concentration and expression of both ETa and ETb receptors was observed in early cardiac tissue. ET-1 was found to increase the frequency of spontaneous Ca2+ oscillations in E10.5 embryonic cardiomyocytes in vitro. Non-specific inhibition of ET receptors with tezosentan caused arrhythmia and bradycardia in isolated embryonic cardiomyocytes and in whole embryonic hearts both in vitro (E10.5) and in utero (E12.5). ET-1-mediated stimulation of early heart rate was found to occur via ETb receptors and subsequent inositol trisphosphate receptor activation and increased SR Ca2+ leak.High ET-1 concentration and expression of both ETa and ETb receptors was observed in early cardiac tissue. ET-1 was found to increase the frequency of spontaneous Ca2+ oscillations in E10.5 embryonic cardiomyocytes in vitro. Non-specific inhibition of ET receptors with tezosentan caused arrhythmia and bradycardia in isolated embryonic cardiomyocytes and in whole embryonic hearts both in vitro (E10.5) and in utero (E12.5). ET-1-mediated stimulation of early heart rate was found to occur via ETb receptors and subsequent inositol trisphosphate receptor activation and increased SR Ca2+ leak.ConclusionEndothelin-1 is required to maintain a sufficient heart rate, as well as to prevent arrhythmia during early development of the mouse heart. This is achieved through ETb receptor, which stimulates Ca2+ leak through IP3 receptors.Endothelin-1 is required to maintain a sufficient heart rate, as well as to prevent arrhythmia during early development of the mouse heart. This is achieved through ETb receptor, which stimulates Ca2+ leak through IP3 receptors.

ABSTRACT Aim Activity of early embryonic cardiomyocytes relies on spontaneuos Ca2+-oscillations that are induced by interplay between sarcoplasmic reticulum (SR) - Ca2+-release and ion currents of the plasma membrane. In a variety of cell types Ca2+-activated K+ current (IK(Ca)) serves as a link between Ca2+ signals and membrane voltage. This study aimed to determine the role of IK(Ca) in developing cardiomyocytes. Methods Ion currents and membrane voltage of embryonic (E9-11) mouse cardiomyocytes were measured by patch-clamp; [Ca2+]i signals by confocal microscopy. Transcription of specific genes was measured with RT-qPCR and Ca2+-dependent transcriptional activity using NFAT-luciferase assay. Myocyte structure was assessed with antibody labelling and confocal microscopy. Results E9-11 cardiomyocytes express small conductance (SK) channel subunits SK2 and SK3 and have a functional apamin-sensitive K+ current, which is also sensitive to changes in cytosolic [Ca2+]i. In spontaneously active cardiomyocytes, inhibition of IK(Ca) changed action and resting potentials, reduced SR Ca2+ load and suppressed the amplitude and the frequency of spontaneously evoked Ca2+ oscillations. Apamin caused dose-dependent suppression of NFAT-luciferase reporter activity, induced downregulation of a pattern of genes vital for cardiomyocyte development and triggered changes in the myocyte morphology. Conclusion The results show that apamin sensitive IK(Ca) is required for maintaining excitability and activity of the developing cardiomyocytes as well as having a fundamental role in promoting Ca2+- dependent gene expression.

Physical activity is an important factor in attaining bone mass. Our aim was to investigate if low to moderate intensity exercise affects bone resorption [serum tartrate-resistant acid phosphatase (TRAP) 5b activity] and formation (serum osteocalcin concentration) in a randomized controlled exercise intervention trial in Finnish middle-aged men. In addition, the relations of these bone turnover markers with bone mineral density (BMD) and serum sex hormone concentrations [circulating testosterone (T), estradiol (E 2 ), and sex hormone-binding globulin (SHBG) concentrations] were evaluated. Serum TRAP 5b activity and osteocalcin concentration were measured at randomization and after 1 and 4 years of the exercise intervention. BMDs of the lumbar spine (L2 -L4), femoral neck, and total proximal femur were measured with a dual-energy X-ray absorptiometry (DXA). At randomization, TRAP 5b activity was strongly correlated with the osteocalcin concentration (Spearman r = 0.541, P < 0.0001). In addition, TRAP 5b activity was significantly correlated with proximal femur BMD values (r = À0.201, P = 0.018) and osteocalcin concentration with femoral neck and proximal femur BMD values (r = À0.187, P = 0.028; r = À0.240, P = 0.005, respectively). Serum E 2 , free E 2 , and free T concentrations were inversely correlated with both bone turnover markers.

The aim of the study was to improve the practical implementation of the dual X-ray absorptiometry (DXA) by converting the areal bone mineral density BMD (BMD(areal)) to volumetric BMD using magnetic resonance (MR) imaging (MRI) because a failure to control for the femoral neck size can lead to erroneous interpretation of BMD values. We also evaluated the feasibility of MR T2* relaxation time in assessing bone mineral status of the femoral neck. Twenty-eight randomly selected 47- to 64-yr-old healthy men were studied. The men had neither unilateral nor bilateral hip osteoarthritis according to radiographs. Bone width, mineral content (BMC), BMD(areal), and apparent volumetric BMD (BMD(vol)) of the right femoral neck were measured with DXA. The BMD(vol) was calculated by approximating the femoral neck to be cylindrical with a circular cross-section (Vol(dxa)). Volumetric measurements from MR (Vol(mri)) images of the femoral neck were also used to create a BMD measure that was corrected for the femoral neck volume (BMD(mri)). T2* measurements were performed with a 1.5-T scanner (Siemens Magnetom 63SP, Erlangen, Germany). A single 10-mm-thick coronal slice was generated on the femur with a repetition time of 60 ms, and nine echo times (4-20 ms) were used to derive T2* values. Vol(mri) correlated positively (r = 0.828, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001) with Vol(dxa). However, the Vol(mri) of the femoral neck was 18% lower than the Vol(dxa). Similarly, the BMD(mri) was related to the BMD(vol) (r = 0.737, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Because of the difference in the volumetric measures, the BMD(mri) of the femoral neck was 21% higher than the BMD(vol) (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). T2* relaxation time showed a significant negative correlation with BMC, BMD(areal), BMD(vol), and BMD(mri) (r = -0.423 to -0.757, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05-0.001). In conclusion, these results are evidence that DXA-derived volume approximations by the cylinder with circular cross-section geometry may lead to lower DXA-derived BMD(vol) values, as compared to true MRI-derived volumetric bone mineral density. Thus, the BMD(vol) may not be an accurate method to calculate the true volumetric BMD in the femoral neck. Our results also suggest that the MRI-derived T2* method may be used to approximate the BMD in the proximal femur.

quantity of bone near a metallic implant. 5,6,8 Changes not already visible on standard X-ray films can be detected with DXA. 1 Radiation for the patient is minimal (under 5 mrem/scan), 7 and the error in repetitive measurements is also small 1.0%-5.3%. 8 Periprosthetic bone loss around failed total hip arthroplasty (THA) has not, however, been quantitated so far. The aim of this study was to measure bone mineral density (BMD) around the loosened femoral stem, using DXA to establish a quantative model of bone loss around the loosened implant. Patients and methods Between December 1993 and August 1997, BMD measurements were performed preoperatively in 30 patients who came for revision THAs at Kuopio University Hospital. Nineteen of these patients (13 women, 6 men) had been unilaterally operated on and were selected for this study. The indication for primary arthroplasty was primary arthrosis in 79% (15/19) of the patients, hip fracture in 16% (3/19), and secondary arthrosis in 5% (1/19) (Table 1). The secondary arthrosis was caused by longstanding corticosteroid treatment for polymyalgia rheumatica. The average age at the time of the revision THA was 69 years (range, 48-82 years). The average time between the primary and revision arthroplasties was 5.2 years (range, 0.4-12.3 years). The femoral implants and fixation method used in the primary operation differed among patients (Table 1). Aseptic loosening was the reason for revision arthroplasty in all patients. Five of these revision arthroplasties were done quite soon (at an average of 2.7 years) after the primary arthroplasty. The loosening of the arthroplasties that failed early was actually caused by cement failure (Boneloc; Polymers Reconstructive, Farum, Denmark). 15 On the Endo-Klinik scale, 6 patients had grade-1 loosening and 13 had grade-2. 2

Background and Aims: Lumbar spinal stenosis (LSS) is the most frequent indication for back surgery in adults aged over 65 years, but about one-third of operated patients have less than good/excellent results from the operation. Awareness of outcome predictors and their predictive values may help clinicians in their assessment of the prognosis of patients when considering surgical treatment. Our aim was to study the preoperative predictors in LSS for a good postoperative outcome (satisfaction with surgery and functional improvement) with a two-year follow-up. Material and Methods: LSS patients (n = 102) completed a questionnaire preoperatively and on two-year follow-up. Preoperative patient-related predictors, self-rated health, comorbidities and preoperative treatment were assessed. Satisfaction with the surgical outcome was assessed with a seven-category scale; satisfaction was determined to be good if the patient response was “condition has considerably improved” or “totally cured...

The objective of this observational prospective study was to investigate the effect of depression on shortterm outcome after lumbar spinal stenosis (LSS) surgery. Surgery was performed on 99 patients with clinically and radiologically defined LSS, representing ordinary LSS patients treated at the secondary care level. They completed questionnaires before surgery and 3 months postoperatively. Depression was assessed with the 21-item Beck Depression Inventory (BDI). Physical functioning and pain were assessed with Oswestry disability index, Stucki Questionnaire, self-reported walking ability, visual analogue scale (VAS) and pain drawing. Preoperatively, 20% of the patients had depression. In logistic regression anal-yses, significant associations were seen between preoperative depression and postoperative high Oswestry disability and Stucki severity scores and high intensity of pain (VAS score). In subsequent analyses, the patients with continuous depression, measured with BDI (60% of the patients who had preoperative depression), showed fewer improvements in symptom severity, disability score, pain intensity and walking capacity than the patients who did not experience depression at any phase. In those patients who recovered from depression, according to BDI-scores (35% of the patients with preoperative depression), the postoperative improvement was rather similar to the improvement seen in the normal mood group. In the surgical treatment of LSS, we recommend that the clinical practice should include an assessment of depression.

Background: Previous research has shown an association between preoperative depressive symptoms and a poorer surgery outcome in lumbar spinal stenosis (LSS). It is not known whether depressive symptoms throughout the recovery period are relevant to the outcome of surgery in LSS. In this prospective clinical study the predictive value of preoperative and postoperative depressive symptoms with respect to the surgery outcome is reported. Methods: 96 patients (mean age 62 years) with symptomatic lumbar spinal stenosis underwent decompressive surgery. They completed the same set of questionnaires preoperatively and 3 months, 6 months, 1 year and 2 years postoperatively. Depressive symptoms were assessed with the 21-item Beck Depression Inventory. Physical functioning and pain were assessed with the Oswestry Disability Index, the Stucki Questionnaire, self-reported walking ability and VAS rating. Logistic regression analyses were used to examine the predictive value of preoperative and postoperative depressive symptoms regarding the surgery outcome. A "good" outcome was defined in two ways: first, by gaining a 30% improvement in relation to the preoperative disability and pain, and second, by having a score at or below the median value for disability and pain on 2-year follow-up. Results: Having elevated depressive symptoms particularly on 3-month follow-up was predictive of a poorer surgery outcome regarding pain and disability: when the outcome was defined as less than 30% improvement from the baseline, the OR's (with 95% confidence intervals) were 2.94 (1.06-8.12), <0.05 for Oswestry and 3.33 (1.13-9.79), <0.05 for VAS. In median split approach the OR was 4.11 (1.27-13.32), <0.05 for Oswestry. Predictive associations also emerged between having depressive symptoms on 6-month and 1-year follow-ups and a poorer outcome regarding disability. The predictive value of elevated depressive symptoms particularly with respect to 2-yeard disability was evident whether the outcome was defined as a 30% improvement compared to the preoperative status or as belonging to the better scoring half of the study population on 2-year follow-up. Conclusions: Preoperative and postoperative depressive symptoms may indicate those patients at greater risk of a poorer postoperative functional ability. For these patients, further clinical evaluation should be carried out, especially during postoperative stages.