Protective role of superoxide dismutase in human sperm motility: superoxide dismutase activity and lipid peroxide in human seminal plasma and spermatozoa.

The levels of superoxide dismutase (SOD), a highly specific scavenging enzyme for superoxide anion radicals (O2-), and lipid peroxide produced by oxygen free radicals were measured in human seminal plasma and spermatozoa. Seminal plasma contained 366.8 +/- 20.9 U/ml (mean +/- SE) of SOD activity. SOD activity in human spermatozoa showed a significant correlation to the number of motile spermatozoa, while the activity in seminal plasma did not relate to the sperm concentration or motility. The lipid peroxide concentration in seminal plasma was 6.22 +/- 0.46 nmol/ml and had no significant relationship to sperm concentration or motility. The malondialdehyde (MDA) concentration in spermatozoa was significantly related to the number of immotile spermatozoa. A decrease in the motility of spermatozoa incubated in medium without seminal plasma was observed after 120 min, while the MDA concentration of the spermatozoa increased. Addition of exogenous SOD (400 U/ml) to the sperm suspension significantly decreased this loss of motility and the increase of the MDA concentration. These data suggest a significant role for SOD in sperm motility. It seems that lipid peroxidation of human spermatozoa may cause loss of motility and that SOD may inhibit this lipid peroxidation. These results suggest that SOD may have a possible clinical application in the use of spermatozoa for in-vitro fertilization (IVF) or artificial insemination.     

Co-expression in CHO cells of two muscle proteins involved in excitation-contraction coupling

Summary Ryanodine receptors and dihydropyridine receptors are located opposite each other at the junctions between sarcoplasmic reticulum and either the surface membrane or the transverse tubules in skeletal muscle. Ryanodine receptors are the calcium release channels of the sarcoplasmic reticulum and their cytoplasmic domains form the feet, connecting sarcoplasmic reticulum to transverse tubules. Dihydropyridine receptors are L-type calcium channels that act as the voltage sensors of excitation-contraction coupling: they sense surface membrane and tranverse tubule depolarization and induce opening of the sarcoplasmic reticulum release channels. In skeletal muscle, ryanodine receptors are arranged in extensive arrays and dihydropyridine receptors are grouped into tetrads, which in turn are associated with the four subunits of ryanodine receptors. The disposition allows for a direct interaction between the two sets of molecules.CHO cells were stably transformed with plasmids for skeletal muscle ryanodine receptors and either the skeletal dihydropyridine receptor, or a skeletal-cardiac dihydropyridine receptor chimera (CSk3) which can functionally substitute for the skeletal dihydropyridine receptor, in addition to plasmids for the ₂, and subunits. RNA blot hybridization gave positive results for all components. Immunoblots, ryanodine binding, electron microscopy and exposure to caffeine show that the expressed ryanodine receptors forms functional tetrameric channels, which are correctly inserted into the endoplasmic reticulum membrane, and form extensive arrays with the same spacings as in skeletal muscle. Since formation of arrays does not require coexpression of dihydropyridine receptors, we conclude that self-aggregation is an independent property of ryanodine receptors. All dihydropyridine receptor-expressing clones show high affinity binding for dihydropyridine and immunolabelling with antibodies against dihydropyridine receptor. The presence of calcium currents with fast kinetics and immunolabelling for dihydropyridine receptors in the surface membrane of CSk3 clones indicate that CSk3-dihydropyridine receptors are appropriately targeted to the cell's plasmalemma. The expressed skeletal-type dihydropyridine receptors, however, remain mostly located within perinuclear membranes. In cells coexpressing functional dihydropyridine receptors and ryanodine receptors, no junctions between feet-bearing endoplasmic reticulum elements and surface membrane are formed, and dihydropyridine receptors do not assemble into tetrads. A separation between dihydropyridine receptors and ryanodine receptors is not unique to CHO cells, but is found also in cardiac muscle, in muscles of invertebrates and, under certain conditions, in skeletal muscle. We suggest that failure to form junctions in co-transfected CHO cell may be due to lack of an essential protein necessary either for the initial docking of the endoplasmic reticulum to the surface membrane or for maintaining the interaction between dihydropyridine receptors and ryanodine receptors. We also conclude that formation of tetrads requires a close interaction between dihydropyridine receptors and ryanodine receptors.     

Physical work capacity and effect of endurance training in visually handicapped boys and young male adults

Summary The purpose of the present study was to evaluate the relationship between several physical fitness parameters and eyesight divided into 3 grades in visually handicapped boys and young male adults, and to investigate the effect of mild exercise training on physical and psychic symptoms as well as cardiorespiratory fitness. Four subjects were totally blind (TB), 6 were semi-blind (SB) and 27 had amblyopia (AM). Physical fitness tests consisted of maximal oxygen uptake (V _{O 2max}), maximal pedalling speed and power, maximal stepping rate, and isometric knee extention strength. Compared with AM and SB groups, the TB group was inferior in all physical fitness parameters. Especially,V _{O 2max} in TB (26 ml · kg^–1 · min^–1) was about 56% of that in agematched Japanese sighted subjects and was significantly low compared with the AM and SB groups. Both muscle strength and maximal pedalling power corresponded to about 50% that of the age-matched sighted group. Six SB and 4 TB students (¯x=17.7 years) were trained for 6 weeks on a bicycle ergometer at an intensity of 50%V _{O 2max}. Training was undertaken for 3 days per week and maintained for 60 min per session. After training, physical and psychic symptoms determined by the Cornell Medical Index improved significantly. These results indicate that low physical work capacity in visually handicapped boys and young male adults is due to the lack of physical activity, and that mild endurance training is effective in improving physical and psychic symptoms as well as cardiorespiratory fitness.     

Effects of erythropoietin on glial cell development; oligodendrocyte maturation and astrocyte proliferation

We investigated the effects of erythropoietin (Epo) in glial cell development, especially the maturation of late stage immature oligodendrocytes and the proliferation of astrocytes. Epo mRNA level in oligodendrocytes was much more prominent than those in neurons or astrocytes, which were the same as those in the young adult kidney, while Epo receptor (Epo-R) mRNA level were almost the same among neural cells, kidney and liver tissues. On immunohistochemical examination, Epo-R expression was also detected in O4-positive immature oligodendrocytes and glial fibrillary acidic protein positive astrocytes. These results suggested that types of both glial cells are responsive to Epo. The numbers of mature oligodendrocytes, which are characterized by myelin basic protein and process development, were increased by treatment with recombinant human Epo (rhEpo) (0.001-0.1 U/ml). The maturation of oligodendrocytes was also enhanced by coculture with astrocytes in vitro. However, when mixed cultured cells (oligodendrocytes+astrocytes) were treated with anti-Epo antibody and/or soluble Epo-R, the differentiation of oligodendrocytes was partially inhibited. Interestingly, high dose rhEpo (1, 3, 10 U/ml) markedly enhanced the proliferation of astrocytes. These results suggested that Epo not only promotes the differentiation and/or maturation in oligodendrocytes, but also enhances the proliferation of astrocytes. It is generally accepted that astrocytes produce Epo, and therefore Epo might act on astrocytes in an autocrine manner. The astrocytes stimulated with Epo may further accelerate the maturation of oligodendrocytes. These comprehensive effects of Epo might also affect the ability of oligodendrocyte lineage cells to promote myelin repair in the normal and damaged adult central nervous system.     

SIRS and CARS: discussion based on the pathologic condition of acute pancreatitis

Relationship between SIRS and CARS in the pathologic condition of acute pancreatitis was discussed. SIRS promotes excessive inflammatory reaction and CARS induces the susceptibility to infection. Both conditions can develop into organ failure in acute pancreatitis. Hence, countermeasures for both conditions are mandatory in the care of patients with acute pancreatitis.     

Sperm morphological assessment based on strict criteria and in-vitro fertilization outcome.

One-hundred-and-twenty-three in-vitro fertilization (IVF) cycles were analysed in order to clarify the influence of strictly normal morphology (SNM) of spermatozoa on IVF outcome. SNM was defined using strict criteria according to Kruger with our modifications. The IVF cycles studied were divided into three groups: %SNM less than 12% (13 cycles), 12 less than 40% (68 cycles), greater than or equal to 40% (42 cycles). The cleavage rates per oocyte were higher in the groups with 12-40% and greater than or equal to 40% of %SNM than in the group with %SNM less than 12%. The embryo transfer rate per cycle increased with increasing %SNM. The overall pregnancy rate per cycle increased with increasing %SNM (7.7% in %SNM less than 12%, 22.1% in 12-40% of %SNM, and 40.5% in %SNM greater than or equal to 40%). The ongoing pregnancy rate per cycle also increased with increasing %SNM (7.7% in %SNM less than 12%, 14.7% in 12-40% of %SNM, and 31.0% in %SNM greater than or equal to 40%). The miscarriage rate was lower in %SNM greater than or equal to 40% (23.5%) than in 12-40% of %SNM (33.3%). It was suggested that %SNM is a good predictor of IVF outcome.     

A comparison of three bioelectrical impedance analyses for predicting lean body mass in a population with a large difference in muscularity

This study tested the hypothesis that, as compared to whole-body bioelectrical impedance (BI) analysis, segmental BI analysis can estimate lean body mass (LBM) more accurately in a population with a large difference in muscularity. In addition to whole-body BI, which determines impedance (Z) between the wrist and ankle, two segmental BI analyses which determine the Z value of every body segment in each of (1) the arms, legs and trunk (distal BI) and (2) the upper arms, upper legs and trunk (proximal BI) were applied to a group of 125 male athletes and 75 non-athletes. The subjects were divided into validation and cross-validation groups. Simple and multiple regression analyses were applied to (length)²/Z (BI index) values for the whole-body and each body segment, to develop the prediction equations of LBM measured using air-displacement plethysmography. In the validation group, the SE of estimation was similar in the whole-body (3.4 kg, 5.4%), distal (3.4 kg, 5.5%) and proximal BI (3.3 kg, 5.2%) analyses. However, the whole-body and distal BI analyses produced systematical errors in the estimates of LBM. Moreover, the residuals in the two methods significantly (P<0.05) correlated with the ratios of BI indices of the upper arms and upper legs to those of the arms and legs, respectively, calculated as variables approximating the relative development of lean tissues at the proximal area of limbs. On the other hand, the proximal BI analysis was validated and cross-validated. Thus, the accuracy of estimating LBM was similar in the whole-body and the two segmental BI analyses. However, the prediction equations derived from the use of the whole-body BI index and a combination of the arms, legs and trunk BI indices produced a systematical error relating to the difference between the limb segments in lean tissue development.     

Determination of metabolic profiles on single muscle fibres of different types

Summary Single muscle fibres separated from extensor digitorum longus (EDL) as well as soleus (SOL) in the Wistar strain male rat in relaxing solution were typed histochemically, then glycolytic and oxidative enzyme activities were determined on the same fibres. Glycolytic enzyme lactate dehydrogenase (LDH), phosphofructokinase (PFK), pyruvate kinase (PK) and creatine kinase (CK) showed highest activities in fast-twitch glycolytic (FG), lower in fast-twitch oxidative glycolytic (FOG) and lowest in slow-twitch oxidative (SO) fibres. Also oxidative enzyme succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) showed highest activities in SO, lower in FOG and lowest in FG fibres. The activities of LDH, PFK, PK and CK in FOG fibres separated from EDL showed higher activity compared to those separated from SOL, whereas the opposite result was obtained for the activities of SDH and MDH. Enzyme activities in a single muscle fibre type were not distinguishable from those of another type, and the activity profiles overlapped over a considerable range. The correlations among the separate enzyme activities of CK, LDH and MDH obtained from the same single fibre overlapped over a considerable range.     

Behaviour of permeation and separation for aqueous organic acid solutions through poly(vinyl chloride) and poly[(vinyl chloride)-co-(vinyl acetate)] membranes

The permeation and separation characteristics of poly(vinyl chloride) (PVC) and poly[(vinyl chloride)-co-(vinyl acetate)] (poly(VC-co-VAc)) membranes were investigated for aqueous organic acid solutions by pervaporation and evapomeation. The PVC membrane preferentially incorporates organic acids and predominantly permeates water from aqueous organic acid solutions. Water permselectivities of these aqueous solutions through the PVC membrane are significantly dependent on high diffusivity of water across the membrane. It was found that the permeation rate increases and the separation factor for the water permselectivity decreases with increasing vinyl acetate (VAc) content in the poly(VC-co-VAc) membrane. Preferential solubility of acetic acid into the poly(VC-co-VAc) membrane increases with the VAc content. This result was explained by a strong affinity between acetic acid and the VAc unit in the poly(VC-co-VAc) membrane.