ACTN3 polymorphism affects thigh muscle area.

Muscle mass is an important factor influencing the activity of daily living in older adults. We aimed to investigate whether alpha-actinin-3 (ACTN3) gene R577X polymorphism affects muscle mass in older Japanese women. A total of 109 women (mean+/-SD, 64.1+/-6.0 years) were genotyped for the R/X variant of ACTN3. Mid-thigh muscle cross-sectional area (CSA) was assessed using MRI and compared using analysis of covariance models adjusted for body weight. In addition, physical activity and protein intake were measured as the living environmental factors affecting muscle mass. The ACTN3 R577X genotype distributions of the subjects were 19, 63 and 27 for the RR, RX, and XX genotypes, respectively. No differences in physical activity and protein intake were observed among the genotypes. The XX genotype showed lower thigh muscle CSA compared with RR&RX genotype (mean+/-SEM; XX: 69.1+/-1.8 cm(2), RR&RX: 73.6+/-1.1 cm(2); p<0.05). The results of the present study suggest that ACTN3 R577X polymorphism influences muscle mass in older Japanese women.

Dextran sulfate suppression of viruses in the HIV family: inhibition of virion binding to CD4+ cells.

The first step in the infection of human T lymphocytes by human immunodeficiency virus type 1 (HIV-1) is attachment to the target cell receptor, the CD4 antigen. This step may be vulnerable to attack by antibodies, chemicals, or small peptides. Dextran sulfate (molecular weight approximately 8000), which has been given to patients as an anticoagulant or antilipemic agent for more than two decades, was found to block the binding of virions to various target T lymphocytes, inhibit syncytia formation, and exert a potent inhibitory effect against HIV-1 in vitro at concentrations that may be clinically attainable in human beings. This drug also suppressed the replication of HIV-2 in vitro. These observations could have theoretical and clinical implications in the strategy to develop drugs against HIV types 1 and 2.

Effect of 12 weeks of moderate-intensity resistance training on arterial stiffness: a randomised controlled trial in women aged 32-59 years.

BACKGROUND: Resistance training has been increasingly incorporated into the overall exercise programme because of its effect on muscle strength, functional capacity and osteoporosis. High-intensity resistance training increases arterial stiffness. However, the effect of moderate-intensity resistance training on arterial stiffness is unknown. OBJECTIVE: To determine whether 12 weeks of moderate-intensity resistance training increases arterial stiffness in middle-aged women. METHODS: 35 middle-aged women (age range 32 to 59 years) volunteered to participate. The subjects were randomly assigned to one of three groups: resistance training (RT) group, aerobic exercise training (AET) group or control group. The RT and AET groups performed 12 weeks of moderate-intensity resistance training or aerobic exercise training (two days/week). RESULTS: In the RT group, one-repetition maximum strength significantly increased after the intervention. Interestingly, aortic (carotid-femoral) pulse wave velocity (PWV; an index of arterial stiffness), and peripheral (femoral-ankle) PWV did not change with moderate-intensity resistance training. In contrast, in the AET group, carotid-femoral PWV significantly decreased after the intervention. Resistance training and aerobic exercise training did not affect blood pressure. CONCLUSIONS: This study found that moderate-intensity resistance training did not increase arterial stiffness in middle-aged women, which may have great importance for health promotion with resistance training.

Ultrastructure of human placental tissue after 6 h of normoxic and hypoxic dual in vitro placental perfusion.

The dual in vitro perfusion model of human placental tissue allows the study of different aspects of placental function, such as metabolism, transport and secretion of proteohormones, cytokines and prostaglandins. The integrity of the perfused placental tissue is an important parameter to validate the perfusion system. Using light and electron microscopy, the morphology of villous tissue was examined before and after six hours of normoxic (n=10) vs. hypoxic (n=10) perfusion. An apical shift of the rough endoplasmic reticulum and occasional vacuoles were found in the syncytiotrophoblast of the terminal villi, the exchange area of the placenta. No unexpected pathological findings were seen before the perfusion experiments and only slight changes with moderate distension of the endoplasmic reticulum after 6 h of normoxic perfusion. After hypoxic perfusions, distinct ultrastructural alterations, such as oedematous villous stroma, swollen or completely destroyed cell organelles (e.g., mitochondria and endoplasmic reticulum), multiple vacuoles inside syncytio- and cytotrophoblasts as well as the microvilli were seen, which leads to an impairment of the placental barrier and other functions. The ultrastructural examination of placental tissue before and after dual in vitro perfusion broadens the knowledge of physiological and pathophysiological processes in the perfused placenta and may be a beneficial part of regular validation.

Effects of leg resistance training on arterial function in older men.

BACKGROUND: Little information is available on the effect of strength training on vascular function, particularly in older people. OBJECTIVE: To determine the effect of resistance training on arterial stiffness and endothelial function in older adults. METHOD: Eleven healthy men (mean (SEM) age 64 (1) years) performed 12 weeks of resistance training involving knee flexion and extension (three sets a day, two days a week). RESULTS: Resistance training increased maximal muscle power by 16% (p<0.0001). Arterial stiffness as assessed by aortic pulse wave velocity did not change with resistance training. Plasma concentration of nitric oxide (NO), measured as its stable end product (nitrite/nitrate), had increased (p<0.05) after resistance training (61.2 (10.4) v 39.6 (3.2) micromol/l). There was no change in plasma concentration of endothelin-1. CONCLUSION: The results suggest that short term resistance training may increase NO production without stiffening central arteries in healthy older men.

Clinical significance of fucose level in glycoprotein fraction of serum in patients with malignant tumors.

Serum fucose content in the glycoprotein fraction was determined in various patients with malignant and benign diseases. The results showed that, in contrast to benign diseases, malignant diseases were characterized by an increased fucose content in the glycoprotein fraction. However, no significant difference was noted in the fucose levels in the mucoprotein fraction. The increased fucose level in glycoprotein in malignant diseases was parallel to the increment in total fucose content in serum, which suggests that the increased levels in total fucose in malignant diseases, reported previously, are primarily due to the increase in fucose-containing glycoprotein.

Effect of diabetes on triiodothyronine and reverse triiodothyronine production in the perfused rat liver and kidney.

This study was undertaken to elucidate the effect of diabetes on the conversion of T4 to T3 and rT3 in the isolated, perfused rat liver and kidney. The livers and kidneys from streptozocin (STZ)-induced (50 mg/kg i.p. 2 wk before killing) diabetic rats with or without T4 (30 micrograms/kg s.c. daily) treatment were perfused for 30 min with a synthetic medium containing T4 (6 micrograms/dl), and production of T3 and rT3 in the tissues was measured by radioimmunoassay. The production of T3 (111 +/- 38 ng/g/30 min, mean +/- SD) and conversion rate of T4 to T3 (19.7 +/- 5.8%) in the liver of diabetic rats without T4 treatment and those (124 +/- 41 ng/g/30 min and 21.6 +/- 4.9%) in the liver of diabetic rats with T4 treatment were significantly lower than those of controls (196 +/- 48 ng/g/30 min and 30.6 +/- 5.2%), respectively. The production of rT3 and conversion rate of T4 to rT3 in the liver of diabetic rats with or without T4 treatment were similar to those of controls. The production of T3 and rT3, and conversion rate of T4 to T3 and T4 to rT3, in the kidney of diabetic rats with or without T4 treatment were not significantly different from those of controls. These results suggest that the liver is far more important than the kidney in the overall reduction in the T4 to T3 conversion that occurs in diabetic rats.

HLA-DR specifications in Japanese with juvenile-onset insulin-dependent diabetes mellitus.

Specific allelic associations vary among ethnic groups. We studied the distribution of HLA-A,-B,-C, and -DR antigens in 34 Japanese juvenile-onset diabetic patients. The focus of our current work was HLS-DR antigens because there have been few studies of Japanese with this disease. A significant increase in the frequency of HLA-DR4 was found in patients but not in unaffected persons: DR4 was found in 56.3% of the patients versus 32.6% of the unaffected persons. However, the negative correlation between DR2 and patients was not statistically significant.

Single-strand-binding factor(s) which interact with ARS1 of Saccharomyces cerevisiae.

Since plasmids containing autonomously replicating sequence(s) (ARS) can transform Saccharomyces cerevisiae cells at high frequency, ARS are considered to be the replication origins of chromosomes. To study the mechanism of initiation of eukaryotic chromosomal replication, we examined protein factors which interact with the ARS1 region located near the centromere of chromosome IV in S. cerevisiae. Using the gel-shift assay, we found protein factors which bound to a single-stranded, 97-bp fragment of the ARS1 region containing the core consensus. Competition experiments with various oligodeoxyribonucleotides (oligos) suggest that a site recognized by the factor(s) was within the element containing the core consensus and adjacent close matches to the core consensus of the minus strand. Indeed, when the oligo containing the minus strand of this element was used as a probe, two oligo-protein complexes were detected. Mutations in the core consensus reduced these binding activities. When the plus-strand oligo of the same region was used as a probe, a retarded band was also detected, but with less specific binding. Considering the fact that the core consensus and close matches to the core consensus are important for ARS function, these results imply that the protein factors detected in this experiment may participate in DNA replication.

Neuroleptic malignant syndrome in a parkinsonian woman during the premenstrual period.

A 45-year-old woman with Parkinson's disease developed neuroleptic malignant syndrome (NMS) despite lack of levodopa withdrawal. She experienced two episodes characterized by indomethacin-resistant hyperthermia, hyperhidrosis, and aggravation of parkinsonism. The symptoms, however, disappeared during menstruation. We suggest that the development of NMS may depend, in part, upon the hormonal state.

A mutation in the microtubule-associated protein tau in pallido-nigro-luysian degeneration.

We detected a missense mutation in exon 10 of tau that causes a substitution at codon 279 (N279K) in a Japanese patient with a familial background of parkinsonism and dementia originally described as pallido-nigro-luysian degeneration. This mutation is the same as one seen in a Caucasian family with pallido-ponto-nigral degeneration. The similarities between these two families suggest a common genetic mechanism that may account for the peculiar distribution of neuroglial degeneration with tauopathy.

Clinical and genetic studies of families with the tau N279K mutation (FTDP-17).

The tau N279K mutation was identified in four separately ascertained families in the United States, Japan, and France and in another recently discovered affected individual in Japan. The authors analyzed genealogical and clinical records and DNA samples. Average age at onset was 43 years; survival time was 7 years. All families exhibited similar clinical features, with parkinsonism, dementia, and supranuclear palsy uniformly seen. A founder effect indicated by a shared disease haplotype was seen only in two Japanese families. The N279K mutation can develop independently in different parts of the world.

The dopamine D1 receptor agonist SKF 38393 suppresses detrusor hyperreflexia in the monkey with parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

A pharmacological study using monkeys, in which parkinsonism was induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), was undertaken to elucidate the mechanism underlying urinary bladder dysfunctions in Parkinson's disease. Under ketamine anesthesia, cystometrograms showed that, in MPTP-treated monkeys, a contraction of the urinary bladder was induced with smaller bladder volume than that in normal monkeys. In MPTP-treated monkeys, subcutaneously injected SKF 38393, a dopamine D1 receptor agonist, significantly increased the bladder volume and pressure thresholds for inducing the micturition reflex without affecting those in normal monkeys. In contrast, subcutaneous injections of quinpirole, a dopamine D2 receptor agonist, and apomorphine, a dopamine D1 and D2 receptor agonist, slightly, but significantly reduced the volume threshold of the bladder for the micturition reflex in both normal and MPTP-treated groups. These results indicate that, in parkinsonism, the degeneration of dopaminergic neurons in the substantia nigra leads to the detrusor hyperreflexia, probably due to a failure of activation of dopamine D1 receptors.

Alterations of life span in the nematode Caenorhabditis elegans under monoxenic culture conditions.

The nematode Caenorhabditis elegans was cultured monoxenically with E. coli as a food source and the influence of the bacterial growth conditions on the life span was studied. When bacterial growth was restricted by reducing the concentration of bactopeptone, which was supplied as the energy source in nematode growth medium (NGM), the nematode's life span tended to be prolonged without a marked effect on postembryonic development. The effect of bactopeptone on the life span was clearly observed during the postreproductive period (that is, after the egg-laying stage of the wild-type C. elegans) rather than during the larval to young adult stage. Evidence is presented that this alteration of the life span was not brought about by any factor in the bactopeptone but by the concentration of bacteria.

Novel aspect of cyclic 3',5'-adenosine monophosphate synthesis in Escherichia coli 3000A1.

A kinetic analysis of cyclic 3',5'-adenosine monophosphate (cAMP) synthesis in an adenine auxotroph of Escherichia coli 3000 was made by assaying the incorporation of [3H]adenine into cAMP during exponential growth. The rate of increase in intracellular [3H]cAMP was very slow (0.1-0.2 pmol/min/DU660). The steady state level was attained at about 40-min incubation after the addition of [3H]adenine, and was estimated to be 5 to 7 pmol/DU660. The rate and level of intracellular cAMP were scarcely affected by growth conditions, such as change of carbon source, whereas the excretion of cAMP into the medium began immediately after the addition of [3H]adenine, and continued at a rate of 5 to 7 pmol/min/DU660 in the glycerol medium. The excretion rate decreased to 1.4 pmol/min/DU660 in the presence of glucose. These results are inconsistent with the view that the excretion rate is dependent on the intracellular concentration of cAMP. Although the decreased rate of cAMP synthesis in the presence of glucose accounts for the permanent catabolite repression of inducible enzyme systems, no immediate depression in cAMP synthesis, which might account for the transient repression, was found after the addition of glucose.

Effect of growth conditions on catabolite repression and cyclic AMP synthesis in Escherichia coli 3000A1.

Catabolite repression of beta-galactosidase synthesis in E. coli 3000A1 (adenine-) was studied under a variety of growth conditions. The differential rate of induced beta-galactosidase synthesis was maximal at the growth rate of 0.75 division per h, irrespective of whether growth conditions were aerobic or anaerobic. The addition of cyclic AMP (cAMP) to the medium partly restored the repressed synthesis of beta-galactosidase under some growth conditions, but showed little or no effect on the enzyme synthesis under other conditions. Although growth rate and profile of beta-galactosidase synthesis in glucose-grown cells were similar to those in arabinose-grown cells, the acceleration of beta-galactosidase synthesis upon the addition of cAMP was found only in glucose-grown cells. The cells aerobically grown in the presence of glycerol, xylose, or arabinose showed a high synthetic rate of cAMP and were insensitive to exogenously supplied cAMP as regards beta-galactosidase synthesis. Although the cells grown with glucose showed similar rates of cAMP synthesis under aerobic and anaerobic conditions, the differential rate of beta-galactosidase synthesis was much higher in the anaerobic state than in the aerobic state. These findings support the idea that catabolite repression found in the strain is caused through two mechanisms, i.e., cAMP-mediated and cAMP-independent ones.

Effects of growth conditions on thymidine nucleotide pools in Escherichia coli.

The cellular levels of thymidine nucleotide derived from [3H]thymine or [3H]thymidine were followed under various environmental conditions with a thymine-requiring mutant of Escherichia coli. It was shown that the pool sizes varied greatly with the growth conditions; that is, with growth temperature, inhibition of DNA synthesis of replacement of thymine with thymidine. In the strain used here, the level of compound X, presumably dTDP-sugar, was very much higher than those of other thymidine nucleotides. It is suggested that the conversion of thymine to thymidine is rate-limiting, while the conversions of thymidine to dTMP, and of dTMP to dTDP are more rapid than other steps in the salvage pathway of thymidine nucleotide.

Choline acetyltransferase from a temperature-sensitive mutant of caenorhabditis elegans.

A temperature dependent paralytic mutant of C. elegans was isolated and mapped to be an allele of the cha-1 gene that has been shown to be the structural gene for acetyl-CoA: choline-O-acetyltransferase (EC 2.3.1.6; ChAT) (Hosono et al., J. Exp. Zool.235, 409-421, 1985; Rand and Russell, Genetics106, 227-248, 1984). In crude extracts from the mutant, ChAT activity was present when assayed at a permissive temperature but not detectable at a temperature that provoked abnormal phenotypes. The mutant ChAT was purified to a specific activity of 2.9 nmol of product min (-1) per mg of protein at 10 degrees C and its enzymatic properties were studied by comparison with the wild-type enzyme. The temperaturesensitivity of the mutant ChAT was so remarkable that no activity was detected over 20 degrees C. This inactivation at higher temperature appeared to be partly reversible. The Km values of the mutant enzyme for choline and acetyl-CoA were about twice of those in the wild-type enzyme, but increased 10- to 20-fold in the presence of high salt concentrations. The mutant enzyme was also more sensitive to sulfhydryl reagents. These findings indicate that depending upon changes in the physical environment, the mutant ChAT may lose the normal-conformation leading to inactivation.

Effect of TSH on conversion of T4 to T3 in perfused rat kidney.

This study was undertaken to elucidate the effect of thyrotropin (TSH) on the conversion of thyroxine (T4) to 3,5,3'-triiodothyronine (T3) in the isolated perfused rat kidney. The kidney was perfused with a synthetic medium containing 20 micrograms/dL T4 and the effect of constant infusion of bovine TSH (125 or 250 microU/mL) on the conversion of T4 to T3 was investigated. T4 uptake in the perfused kidney was not changed by the addition of TSH. However, the release of T3 (89 +/- 11 ng/g/30 min, mean +/- SD), tissue T3 (190 +/- 23 ng/g/30 min), net T3 production (227 +/- 37 ng/g/30 min), and the conversion rate of T4 to T3 (9.5 +/- 1.6%) in the kidney perfused with 250 microU/mL TSH were significantly (P less than 0.005) greater than those in controls (63 +/- 9, 143 +/- 15, 152 +/- 36 ng/g/30 min, and 6.3 +/- 1.9%), respectively. Degradation rate of T3 in perfused rat kidney was not changed by the addition of 250 microU/mL TSH. These results suggest that TSH may directly affect renal iodothyronine-monodeiodinating activity in rats in vitro.

Tendinous movement of a human muscle during voluntary contractions determined by real-time ultrasonography.

The degree of shortening or lengthening of muscles during joint actions has not been clarified in humans, although such information is essential in understanding human muscle functions. In this study, the tendinous movement of a muscle was determined by real-time ultrasonography during voluntary contractions. The tibialis anterior muscle (TA) was tested in five healthy men who performed dorsi- and plantar flexion movements (shortening and lengthening of TA) at two frequencies (0.1 and 1.5 Hz). The insertion point (eta) of fascicles onto the aponeurosis was clearly visualized on the ultrasonogram, and its position relative to a fixed marker moved proximally and distally according to dorsi- and plantar flexion of ankle joint. The movement of eta occurred in phase with the angular change of ankle joint, giving high correlations (r = 0.93 to 0.97) between the displacement of eta and the angle. The displacement of eta for one radian of joint angle change, 46.5 +/- 1.7 (SD) mm, was comparable to the reported moment arm of TA. The present method has many potential applications in the field of muscle physiology and biomechanics in humans.