Relationships between the serum levels of soluble leptin receptor and free and bound leptin in non-pregnant women of reproductive age and women undergoing controlled ovarian hyperstimulation

BACKGROUND: The aim of this study was to investigate the relationships between the serum levels of soluble leptin receptor (SLEPR), and total, free and bound leptin, and the change in the serum SLEPR level during an IVF cycle. METHODS: Serum concentrations of leptin and SLEPR were measured in 50 Japanese women of reproductive age, and 20 patients participating in an IVF programme. The total leptin was fractionated into free and bound portions by gel filtration chromatography. RESULTS: The SLEPR level was negatively correlated with the body mass index (BMI) (r = -0.548, P < 0.0001), total leptin (r = -0.433, P < 0.0001), the percentage of free leptin (r = -0.732, P < 0.0001) and the absolute free leptin concentration (r = -0.506, P < 0.0001). The SLEPR level was positively correlated with the percentage of bound leptin (r = 0.730, P < 0.0001), whereas there was little variation in the absolute bound leptin concentration, regardless of the BMI or SLEPR concentration. During the IVF cycle, total and free leptin elevated during maximal ovarian stimulation, whereas there was no significant difference in the SLEPR concentration. CONCLUSIONS: The results demonstrate a skillful mechanism where a change in the serum SLEPR level regulates, in part, the biological activity of leptin in the circulation.     

Nine-bp repeat polymorphism in exon 1 of thehMSH3 gene

Summary We have identified a polymorphic 9-bp repeat sequence in exon 1 of thehMSH3 gene using polymerase chain reaction (PCR). Five alleles were observed in unrelated Japanese individuals with heterozygosity of 0.57.     

A hamster temperature-sensitive G1 mutant, tsBN250 has a single point mutation in histidyl-tRNA synthetase that inhibits an accumulation of cyclin D1

Background: We have previously isolated a series of temperature-sensitive mutants for cell-proliferation from the BHK21 cell line, derived from the golden hamster. These mutants proliferate at 33.5 °C, the permissive temperature, but not at 39.5 °C the restrictive temperature. Using DNA-mediated gene transfer, human genes complementing these ts mutants were cloned.
Results: At 39.5 °C the tsBN250 cell line, a temperature-sensitive mutant of the BHK21 cell line, had a defect in the G1 phase, but not in the S phase. The human gene complementing tsBN250 cells was found to encode histidyl-tRNA synthetase. Indeed, the tsBN250 cell line had a single base change—guanine to adenine at the second position of the 362nd codon of hamster histidyl-tRNA-synthetase, converting arginine to histidine. Following release from serum starvation, cyclin E, but not cyclin D1, was accumulated, while, at 39.5 °C, the mRNA of cyclin D1 was normally expressed in tsBN250 cells. A similar inhibition of cyclin D1 accumulation was observed in another ts mutant, tsBN269, which has a single point mutation in lysyl-tRNA synthetase. Overexpression of cyclin D1 enabled tsBN250 cells to enter the S phase.
Conclusion: tsBN250 cells have a single point mutation in histidyl tRNA synthetase that causes a loss of histidyl-tRNA synthetase activity which in turn reduces the content of cyclin D1, but not of cyclin E, thereby resulting in G1 arrest.     

Expression of tumor necrosis factor ligand superfamily costimulatory molecules CD27L, CD30L, OX40L and 4-1BBL in the heart of patients with acute myocarditis and dilated cardiomyopathy.

BACKGROUND: T-cell-mediated myocardial damage is known to be involved in acute myocarditis and dilated cardiomyopathy. Recently, we found that tumor necrosis factor (TNF) ligand superfamily costimulatory molecules, especially 4-1BBL, played an important role in the myocardial damage of murine acute viral myocarditis. METHODS AND RESULTS: To investigate the roles for CD27L, CD30L, OX40L and 4-1BBL, which belong to TNF ligand superfamily, in the development of acute myocarditis and dilated cardiomyopathy, we analyzed the expression of these antigens in the myocardial tissues of patients with acute myocarditis and dilated cardiomyopathy. We also examined expression of the receptors for these molecules, CD27, CD30, OX40 and 4-1BB, which belong to TNF receptor superfamily, on the infiltrating cells. Strong expression of CD27L, CD30L and 4-1BBL and weak to moderate expression of OX40L was found in the cardiac myocytes of patients with acute myocarditis. Moderate expression of CD27L, CD30L and 4-1BBL and weak expression of OX40L was found on the cardiac myocytes of patients with dilated cardiomyopathy. Most of the infiltrating cells expressed CD27, CD30 and 4-1BB and a part of the infiltrating cells expressed OX40. CONCLUSIONS: Our findings suggest that expression of TNF ligand superfamily costimulatory molecules on cardiac myocytes may play a role in the cell-mediated myocardial damage in patients with acute myocarditis and dilated cardiomyopathy as in murine viral myocarditis.     

Positioning of actin filaments and tension generation in skinned muscle fibres released after stretch beyond overlap of the actin and myosin filaments

Summary Skinned fibres from frog semitendinosus muscle were stretched in relaxing solution from a sarcomere length of 2.5 m to greater sarcomere lengths, and then shortened back to the original length. Fibres could be stretched up to sarcomere lengths of 3.3 m, and reshortened fully. If the original stretch was to a sarcomere length greater than 3.3 m, the extent of recovery was dependent on the magnitude of the stretch and the number of times the stretch/shorten cycle was repeated. When the original stretch was to sarcomere lengths beyond overlap of the thick and thin filaments, the thin filaments did not re-enter the thick filament array but buckled at the A-I junction. If these fibres were subsequently activated and contracted, the thin filaments re-entered the thick filament array, taking up approximately their former positions, and allowing reduced development of isometric tension.Finally, the present observations support the view that calcium-induced interactions of actin and myosin filaments in the presence of ATP play an important role in the organization of myofibrillar structure during differentiation (compare Hayashiet al. 1977; Shimada & Obinata, 1977).     

Heterotopic transplantation of the failing rat heart as a model of left ventricular mechanical unloading toward recovery

The left ventricular assist device (LVAD) is usually used in patients with end-stage heart failure as a bridge to transplantation. Recently, some studies have reported functional recovery with the use of an LVAD, although the mechanisms responsible for recovery are not fully understood. We investigated the functional recovery of the infarcted, failing rat heart in response to mechanical unloading after heterotopic transplantation. Heart failure was induced in Lewis rats by ligating the left anterior descending artery. After 4 weeks, the infarcted hearts were harvested and heterotopically transplanted. The transplanted infarcted heart was removed after 2 weeks of unloading and examined for hypertrophy and fibrosis, as well as for mRNA levels encoding for brain natriuretic peptide, sarco(endo)plasmic reticulum Ca(2+)-ATPase2a (SERCA2a), and beta1- and beta2-adrenergic receptors. Normal and infarcted rats without transplantation served as control animals. The infarcted heart was hypertrophied as evidenced by an increase in heart weight and myocyte diameter. After unloading the infarcted heart for 2 weeks, there was a decrease in heart weight and myocyte diameter. However, the percentage of myocardial fibrosis increased after unloading. The mRNA expression of brain natriuretic peptide and the beta2-adrenergic receptor significantly improved after mechanical unloading. The levels of SERCA2a mRNA tended to increase after unloading. In conclusion, unloading the failing, infarcted heart can help normalize left ventricular hypertrophy and cardiac gene expression. This unloading model appears to partially mimic the conditions of hemodynamic support with an LVAD in heart failure patients and potentially offers insights into the mechanisms of functional recovery.     

Education of medical technologists in North America

The increasing complexity of diseases and advancing medical technologies have recently raised the number of test items and their use. This has caused each department to ask for clinical support by medical technologists, including consultation services on clinical laboratory tests in Japan. Under these circumstances, we think it is necessary to consider a Japanese education system for medical technologists to foster people with advanced ability capable in providing adequate clinical support. It is important that we study medical technologist systems and education systems superior to than ours. Therefore, to investigate the state of the Japanese education system for medical technologists, we conducted a comparison between the medical technologist systems and education systems in foreign countries and those of Japan. The social background in which medical technologists are positioned, their scope of work, and the education systems overseas are different from Japan on many points and we were given many suggestions for what a system in Japan should be like.     

EARLY CHANGES IN CEREBRAL ANEURYSMS IN THE INTERNAL CAROTID ARTERY/POSTERIOR COMMUNICATING ARTERY JUNCTION

In order to obtain information about preaneurysmal changes, the junction of the internal carotid artery/posterior communicating artery (ICA/PComA) in the circles of Willis in subjects with aneurysms at sites other than the junction, and in control subjects without aneurysms, were studied by light microscopy.
Small evaginations and thinnings of the media with and without dilatation were observed at the apical areas of the forks with a significantly higher incidence in the aneurysm series than in the control, suggesting some predisposing factor in subjects with aneurysms. As well as funnel-shaped dilatations previously described as the only type of ICA/PComA preaneurysmal change, other more localized types were observed. All the small evaginations and about half of the thinnings and dilatations were observed at the apex in association with a medial gap, but the other half occured at some distance from the apex. The thinned arterial wall showed degenerative changes of the elastic lamina and media. Intimal pads were observed at the apex, the ICA/PComA lateral angle and the ICA stem/branch curve. Their combination with preaneurysmal changes was more frequent in the aneurysm series in comparison with the control.
Degenerative changes of the elastic lamina and media caused by hemodynamic stress due to branching structures including intimal pads are thus presumed to be the initial lesions existing prior to aneurysm formation.     

EFFECTS OF GLUCOCORTICOIDS ON DIFFERENTIATION OF ZONA GLOMERULOSA OF FETAL ADRENAL CORTEX OF RATS

The tissue differentiation of the zona glomerulosa of the fetal adrenal cortex of rats was studied by giving experimental treatments to the fetus in vivo. A low-glucocorticoid-condition was given to the fetus by bilateral adrenalectomy of pregnant rats for removing exogenous glucocorticoids from the fetus, and by brain aspiration of the fetuses for removing the fetal pituitary gland (ACTH) and endogenous glucocorticoids. When the fetus was placed under a low-glucocorticoid-condition for the last couple of days of gestation, poor differentiation of the zona glomerulosa occurred speciflcally in the fetal adrenal cortex. The degree of the poor differentiation seemed to be proportional to the duration of the low-glucocorticoid-condition. Supplemental administration of glucocorticoids could prevent this poor differentiation of the zona glomerulosa. These results indicate that the tissue differentiation of the zona glomerulosa of the fetal adrenal cortex depends much on glucocorticoids.