Biomedical subjects

H Iwata

Publications and source records attributed to H Iwata.

At least 325 records · Page 18Linked to original sources

PubMed1997

Histologic examination of meniscal repair in rabbits.

After a cylindrical defect was made in the anterior segment of the lateral meniscus in rabbits, the meniscus was examined postoperatively at 2, 8, and 13 weeks. Horizontal sections were prepared at a central level of the meniscus from each sample and stained with hematoxylin and eosin, Safranin O, and Masson trichrome. In addition, part of the tissue was immunologically stained with antibodies to chondroitin-4-sulfate, chondroitin-6-sulfate, keratan sulfate, and Type II collagen. Hematoxylin and eosin stained specimens were analyzed for repair tissue by microscopic study, and the cells observed in repair tissue were found to change from fibroblastlike cells to chondrocytelike cells with the progress of repair. Safranin O stained specimens showed a higher stainability with the progress of repair, confirming that abundant proteoglycan existed. In cases of complete healing, the repair tissue immunostained with antibodies to chondroitin-4-sulfate, chondroitin-6-sulfate, keratan sulfate, and Type II collagen showed a higher stainability than did the surrounding meniscus tissue. Thus, it is possible that the repair tissue might have been hyalinelike cartilage.

Animals↗

PubMed1997

Effect of dibutyryl cyclic adenosine monophosphate on skeletal muscle reperfusion injury in the rat.

To clarify the action of dibutyryl cyclic adenosine monophosphate (DBcAMP) on reperfused ischemic muscle, experiments were conducted using the hindlimbs of 18 male Lewis rats. At the midportion of the thigh all tissues except for the femoral artery and vein were transected, and a route for continuous intravenous infusion was secured in a contralateral limb vein. After inducing total ischemia by clamping the femoral artery and vein with a vascular clamp for 4 h, the limb was reperfused for 1 h. Blood flow was then compared using the hydrogen gas clearance method in a group in which DBcAMP 10 mg was continuously infused from a vein in the contralateral hindlimb from 1 h prior to the induction of ischemia to 1 h after the completion of ischemia (DBcAMP group), a group in which saline was infused in the same manner (control group), and a group which was subjected to biopsy alone (biopsy group). The percent change in blood flow was significantly higher in the DBcAMP group than in the control group at 15 and 30 min after the release of the clamp. Adenosine triphosphate (ATP), phosphocreatine (PCr), and lipid peroxide (LPO) were measured in tissue samples obtained 1 h after reperfusion. Serum LPO was measured in blood samples collected at the same time. ATP values were higher in the DBcAMP group than in the control group. PCr was significantly higher in the DBcAMP group than in the control group. LPO levels in skeletal muscle tissue did not differ significantly between the DBcAMP and control groups. In contrast, serum LPO levels were significantly lower in the DBcAMP group than the control group. On morphologic analysis the control and DBcAMP groups showed normal vascular endothelial cells and absence of the 'no-reflow' phenomenon. These data confirm that in this reperfusion model the administration of DBcAMP enhances the viability of skeletal muscle cells. Moreover, mediated by an effect on vascular endothelial cells this agent is thought to be of help in mitigating the vascular endothelial cell injury occurring in acute ischemic injury. DBcAMP may be a useful agent in mitigating skeletal muscle ischemia-reperfusion injury.

Adenine Nucleotides↗

PubMed1997

Encapsulation of mammalian cells into synthetic polymer membranes using least toxic solvents.

Immunoisolation, that is, enclosure of cells within a semipermeable membrane to protect them from immunological rejection, may enable the transplantation of cells without use of immunosuppressive drugs. Therefore, in addition to naturally-occurring ionic polymers, several synthetic nonionic polymers which can form dense and strong membranes in water have been studied as materials for immunoisolation. However, such nonionic polymers are required to be soluble in organic solvents which are mostly cytotoxic. In this report we describe enclosure of insulin-releasing cells into water-insoluble poly(2-hydroxyethyl methacrylate) and poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) membranes using X-ray contrast medium as a solvent without use of any special apparatus. The contrast medium employed in our study is iopamidol aqueous solution. Insulin release was observed for 1 months when insulin-releasing cells were encapsulated into these membranes. The permeability of five solutes through the membranes prepared from the iopamidol aqueous solution was also studied to determine their potential immunoisolative efficacy.

Animals↗

PubMed1997

Possible therapeutic effect of T-794, a novel reversible inhibitor of monoamine oxidase-A, on post-stroke emotional disturbances, assessed in animal models of depression.

Emotional disturbances, such as lack of motivation or depression, are common after stroke. The drugs mainly used to treat these syndromes in Japan are the cerebral metabolic enhancers whose biochemical and pharmacological profiles are similar to those of antidepressant drugs. In order to examine the possible therapeutic effect of T-794 [(5R)-3-(6-(cyclopropylmethoxy) 2-naphthalenyl)-5-(methoxymethyl) 2-oxazolidone], a new reversible inhibitor of monoamine oxidase (MAO) type A, on those emotional disturbances, its antidepressant activity was compared with those of major cerebral metabolic enhancers in rodents with or without treatment of cerebral ischemia. Oral administration of T-794 potently prevented reserpine-induced ptosis (ED50 = 4.41 mg/kg), akinesia (ED50 = 3.29 mg/kg), and hypothermia (minimum effective dose = 3 mg/kg) in mice. It was at least 3.7, 13.0, and 3.3 times more potent than cerebral metabolic enhancers tested (indeloxazine, bifemelane, amantadine and idebenone) in antagonism of the ptosis, the akinesia, and the hypothermia, respectively. Effect of T-794 was also examined in the behavioral despair test in rats subjected to forebrain ischemia. The ischemia was induced by a combination of bilateral common carotid artery occlusion (15 min) and systemic hypotension (sodium nitroprusside 5 mg/kg, s.c). From 13 d after the surgery, drugs were orally administered twice daily 7 times, and following the last administration rats were assessed for their behavior. T-794 reduced the duration of immobility in the behavioral despair test at 30 mg/kg without affecting spontaneous motor activity, whereas indeloxazine showed no significant effect. Antidepressant-like activity of T-794 was suggested in rodents with as well as those without cerebral ischemia. The results suggest that T-794 may make an important contribution to the treatment of emotional disturbances following stroke.

Animals↗

PubMed1997

Plasma triglyceride-decreasing components of pine needles.

An ultrafiltrate (M.W. < 10000) of 0.1 M acetic acid extract from Japanese red pine needles was treated with Sep-Pak Vac C18, and an absorbable fraction (pine aqueous components fraction, PAC) was obtained. Since the intraperitoneal administration of PAC to rats decreased plasma triglyceride in a screening test for bioactivity, we tried to further isolate the active substances with respect to this triglyceride-decreasing action. Active substances were precipitated by acid, and we then divided them into fractions using reversed phase HPLC. The active fractions were hydrolyzed, then the hydrolysate was re-separated by the same HPLC system. Negative ion mode FAB-LC/MS of the bioactive fractions of this hydrolysate revealed an [M-H] molecular ion peak at m/z 169 and 321. The 13C-NMR spectra were consistent with those of authentic gallic acid and galloyl gallic acid, a dimer of gallic acid. Authentic gallic acid also showed a triglyceride-decreasing action, and galloyl gallic acid even more markedly decreased triglyceride. These findings suggest that the triglyceride-decreasing action of Japanese red pine needles is due to these polyphenol compounds. In addition, amino acids were also detected in the hydrolysate of PAC, indicating that the components in Japanese red pine needles that decrease triglycerides are complexes of a hydrolyzable tannin, which contains gallic acid and galloyl gallic acid as components and peptides.

Amino Acids↗

PubMed1997

[Effects of voluntary exercise on nonspecific immunological mechanisms in mice].

We studied the effects of voluntary exercise on nonspecific immunological mechanisms in mice. In this study, 7 week old male ICR mice were divided into two groups: a non-exercise group (control) and a group given voluntary exercise (Vex group). Each mouse of the Vex group was kept in an individual cage equipped with a voluntarily revolving wheel that the mouse had free access to. The duration of voluntary exercise was 3 days per week for 8 weeks. The following results were obtained: 1) After 8 weeks of voluntary exercise, food consumption, the weight of the anterior tibialis muscle and succinate dehydrogenase activity in the anterior tibialis muscle increased significantly in the Vex group compared to the control group. 2) By means of the carbon clearance method, phagocytosis of the reticuloendothelial system was increased in the Vex group. 3) Glucose consumption capacity and O-2 production capacity of peritoneal macrophages (M phi) were significantly increased in the Vex group compared to the control group. 4) The acid phosphatase (APH), beta-glucuronidase (GLU) and lactate dehydrogenase (LDH) activities of peritoneal M phi increased significantly in the Vex group. 5) Concanavalin A (Con A)-induced cell proliferation in the spleen was high in the Vex group. Based on the above findings, it may be surmised that voluntary exercise enhances nonspecific immunological mechanisms and thereby improves the host defense mechanisms in mice.

Animals↗

PubMed1997

[Relationships between maximal oxygen uptake (VO2max) and physical activity, blood pressure and serum lipids].

This study was conducted to investigate the relationships between maximal oxygen uptake (VO2max) and physical activity (occupational and leisure time), blood pressure, and serum lipids. The subjects of this study (n = 727) were those who participated in a "health check for 30-year-olds" in the city of Gifu, Japan, during the period from April 1991 to March 1993. Individuals with a medical history and/or undergoing treatment for coronary heart disease (CHD), other heart diseases, hypertension, diabetes mellitus, liver disease, or renal disease were excluded. Finally, 411 males (30 yrs of age) were considered for this study. VO2max was estimated according to the method of Astrand & Rhyming. The results can be summarized as follows: 1. Both occupational and leisure time physical activity were independently related to VO2max. In subjects with light and moderate occupational physical activity, VO2max was affected by leisure time physical activity rather than occupational physical activity, and in those with heavy occupational physical activity, it was affected by both occupational and leisure time physical activity. 2. According to the results of multiple regression analysis, VO2max adjusted for body mass index, smoking, and alcohol was associated significantly with systolic blood pressure (P < 0.0001), high density lipoprotein cholesterol (HDLC) (P < 0.0001), triglyceride (P < 0.0001), and the (total cholesterol-HDLC)/HDLC ratio (P < 0.0001). From the results obtained it may be concluded that VO2max can be considered as a factor to decrease the risk of CHD.

Adult↗

PubMed1997

[Pulse phenomenon of continuous white noise with interrupted pure tone].

The researches of masking made it clear that there is a bandpass like a filter in the auditory system. This is called the auditory filter and its central frequency is thought to be the frequency of an acoustic signal. If there exist this kind of filter, the authors expected that the noise image which is perceived when pure tone and noise simultaneously presented is different from the one which is perceived when noise is presented independently. The authors chose an interrupted pure tone as an acoustic signal and continuous white noise as noise, and experimented to investigate the pure tone effect on perception of white noise. As a result, two stimulus tones induced three sound images, which are sound images of continuous noise, a pure tone and pulsed noise. The sound image which listeners did not expect to hear was the pulsed noise image. This phenomenon was thought to be an auditory induction; the inducer is the sound image of the white noise presented with the silent part of pure tone of interrupted pure tone and the inducee is that of the white noise presented with pure tone part of interrupted pure tone. This pulse phenomenon suggests that pure tone change the loudness of white noise. This finding is interesting for researches of auditory mechanism and for the field of hygienics with protecting the auditory system and improving hearing under the noisy environment.

Acoustic Stimulation↗

PubMed1997

Activation of macrophages by sulfated glycopeptides in ovomucin, yolk membrane, and chalazae in chicken eggs.

Sulfated glycopeptides in ovomucin, chalazae and yolk membrane were found to activate cultured macrophage-like cells, J774.1, and TGC-induced macrophages from the peritoneal cavity of male mice. The macrophage-stimulating activity was estimated by the growth and morphology of the cells, H2O2 generation, and interleukin-1 (IL-1) production from the cells. The in vitro culture assay with macrophages showed that the protease digests of ovomucin, yolk membrane, and chalazae induced morphologic alteration and increased H2O2 generation and IL-1 production in lower concentration (100 micrograms/ml). The isolation of the components having macrophage-stimulating activity was attempted to elucidate the molecular mechanism. The O-linked carbohydrate chains, consisting of N-acetylgalactosamine, galactose, N-acetylneuraminic acid and sulfate, in the sulfated glycopeptide were identified as a component having macrophage-stimulating activity.

Animals↗

PubMed1997

Low back pain among different groups of subjects exposed to hand-arm transmitted vibration.

OBJECTIVES: The purpose of this study was to investigate the prevalence of low back pain (LBP) among various groups of subjects exposed to hand-arm transmitted vibration, and to compare the prevalence of LBP of these subjects with that of non-exposed groups. METHODS: The subjects of this study were 13 groups of males and 3 groups of females of working population leaving in a certain city located in the central part of Japan. By means of a questionnaire, interviews, field visits, or annual health examination, information on age, working career, working posture, various types of tools used, and experience of having LBP during the 12 months preceding the completion of the questionnaire were collected. The subjects' age ranged between 22 and 69 years. All subjects were classified into 5 categories, and the prevalence of LBP was obtained for them. RESULTS: On the whole, complaints of LBP among male and female green tea and strawberry farmers were most frequent. There was a large variation (16.0-72.2%) in the prevalence of LBP among subjects operating vibrating tools. Among three groups of health care professionals, the prevalence of LBP was in the range of 36.5-53.0%. The senior doctors had less complaints of LBP. The prevalence of LBP among subjects who had sedentary jobs was in the range of 41.7-45.9%, and almost as high as that in blue-collar workers using vibrating tools. The prevalence of LBP among females exposed to hand-arm transmitted vibration was between 26.1 and 63%. The prevalence rates of LBP among vibration exposed subjects were plotted against the vibration magnitude of tools used by the same subjects reported in our previous study; however, no significant correlation could be obtained between the prevalence of LBP and vibration values. CONCLUSIONS: Exposure to segmental vibration is less likely to be a risk factor in increasing prevalence of LBP. A higher prevalence of LBP in some groups provide strong evidence for a dominant work-related etiology in developing LBP. Regarding data presented in this study and by a review on scientific literature, suggestions for improving working posture were presented. It seemed that to decrease the risk of LBP among these subjects, special attention should be paid to stimulating the adoption of an ergonomic working posture and to ergonomic training.

Adult↗

PubMed1997

Development of a dural substitute from synthetic bioabsorbable polymers.

A new bioabsorbable composite sheet was developed to provide a substitute for the dura mater and was evaluated histologically and biomechanically using rats and rabbits. This composite, composed of two L-lactic acid-epsilon-caprolactone (50% L-lactic acid, 50% epsilon-caprolactone) copolymer films and a poly(glycolic acid) nonwoven fabric, displayed good mechanical properties and was completely absorbed 24 weeks after implantation in the back of rats. Histological evaluation of the composite sheet was undertaken by implanting it in 31 rabbits with dural defects and examining the sites of implantation 2 weeks to 26 months later. No infection, cerebrospinal fluid leakage, evidence of convulsive disorders, significant adhesion to underlying cortex, or calcification was noticed in any cases. In addition, the regenerated duralike tissue had a high pressure-resistant strength 2 weeks after implantation. The authors conclude that this new bioabsorbable composite sheet can be successfully used as a dural substitute.

Absorption↗

PubMed1997

Subjective symptoms among motorcycling traffic policemen.

OBJECTIVES: This study investigated the prevalence of subjective symptoms among current and former motorcycling policemen. METHODS: The subjects of this study consisted of 46 current and 72 former motorcycling traffic policemen from a certain city located in the central part of Japan. They were requested to reply to questions on a self-administered questionnaire regarding age, work history, and subjective symptoms (16 items) during the month preceding the completion of the questionnaire. RESULTS: Shoulder stiffness and low-back pain were frequently encountered. On the whole, the prevalence of subjective symptoms was higher among the current motorcycling policemen, even though they were younger. Assessing the prevalence of subjective symptoms by the median value of experience of motorcycle riding revealed that the high-exposure subgroup in the group that currently ride motorcycles had higher prevalence rates for all the symptoms. CONCLUSIONS: The prevalence of subjective symptoms among currently motorcycling traffic policemen seems to be transient, and it declines after the cessation of motorcycle riding or the reallocation to other worktasks, such as office work.

Adult↗

PubMed1997

Basic technology of simulation system for laparoscopic surgery in virtual environment with force display.

A basic simulation system for laparoscopic surgery was constructed. The system consists of force display in a virtual environment construction system. Recently, laparoscopic surgery has become popular around the world. However, this operation strategy requires very high dexterity, so that only some medical doctors can use it. Doctors can see the human organs in a three-dimensional environment in the case of ordinary operations. On the other hand, in the case of laparoscopic surgery, doctors can only see a narrow space in a two-dimensional environment on a CRT monitor and tactile information is decreased during operation procedures. We therefore developed a basic technology of surgical simulator for laparoscopic surgery. The focus of our research is the presentation of resistance from virtual organs.

Computer Simulation↗

PubMed1997

Sociocultural dilemma of Japanese steeplejacks.

Japanese steeplejacks are good at working in high places as construction workers, and they have been called tobi for a longtime. They now play an important role in completing modern civil engineering projects and in the construction of high-rise buildings; however, their lifestyle is considered by most to be quaint but outdated. Originally, they were unskilled workmen at construction sites. In the 18th century, they were engaged in repairing houses or setting up scaffolding, helping carpenters, but they worked as firefighters whenever fires broke out. Their traditional work system did not change throughout the Meiji era, although Japanese society became greatly modernized. After World War II, the industrialization of Japanese society required highly developed technology in civil engineering and architecture. This provided an opportunity for them to establish their positions as trained professional workers. However, the number of skilled tobi professionals has continued to decrease because the younger generation does not consider this profession desirable career. Improving not only the professional skills but also the way of living to the extent as a modern high-tech society demands will be the key for the tobi's work system to become attractive.

Career Choice↗

PubMed1997

Administration of bisphosphonate prevents disuse bone atrophy induced by tail suspension.

We recently demonstrated that osteopenia induced by rat tail-suspension was associated with an initial increase in bone resorption. To study the significance of the increase in early bone resorption for osteopenia, we investigated whether administration of YH529, a third-generation bisphosphonate, prevents the development of osteopenia as evidenced by increased wet weight of the femur, together with its calcium and phosphorus contents, when compared with those of tail-suspended rats treated with the vehicle alone. These results suggested that the initial increase in bone resorption plays an important role in the development of osteopenia induced by tail suspension.

Animals↗

PubMed1997

Simultaneous quantitative analyses of c-erbB-2 protein, epidermal growth factor receptor, cathepsin D, and hormone receptors in breast cancer.

The overexpression of c-erbB-2 protein (ErbB2), epidermal growth factor receptor (EGFR), and/or cathepsin D (CD) in breast cancer is known to be a poor prognostic factor. Eighty frozen breast cancer specimens obtained at the initial operation were examined for ErbB2, EGFR, and CD by immunohistochemical assay (ICA) and enzyme immunoassay (EIA). Estrogen and progesterone receptors (ER and PgR) were measured simultaneously by EIA. The mean values +/- 1SD for ErbB2, EGFR and CD were 141 +/- 400 U/mg membrane protein (range: 0-3385), 4.88 +/- 4.33 fmol/mg membrane protein (range: 0-21.1), and 47.1 +/- 32.8 pmol/mg cytosol protein (range: 4.7-182), respectively. The percentage of specimens positive for ErbB2, EGFR, and CD was 12.5, 38.8, and 35%, when the tentative cutoff value were used as 200 U/mg protein, 5 fmol/mg protein, and 50 pmol/mg protein, respectively. These E1A results were correlated with ICA, EGFR and ER were negatively correlated. Although the prognostic value of ErbB2 and EGFR was superior to hormone receptors, ErbB2 and EGFR were interior as predictors compared with lymph node involvement and tumor size. Quantitation of ErbB2, EGFR, and CD can be performed readily using the same specimen in which hormone receptors are measured.

Adult↗

PubMed1997

[Evaluation of the relation of job stress and food intake to hyperuricemia].

To evaluate the relation of job stress and food intake to hyperuricemia, a case-control study was performed in male subjects who had undergone complete physical examinations. Cases (n = 113) were those with hyperuricemia of over 7.5 mg/dl and controls (n = 113) were those with serum uric acid of less than 7.5 mg/dl. Stepwise regression analysis was performed using sixteen items which were significantly related to hyperuricemia by McNemar's method. Consequently, four items; "negative attitude toward work (Odds ratio 5.22, p < 0.01)", "tendency to become competitive in the job and other areas (Odds ratio 5.54, p < 0.01)" in type A behavior, "high meat consumption (Odds ratio 6.94, p < 0.01)", and "high fat intake (Odds ratio 4.05, p < 0.01)", were significantly related to hyperuricemia.

Adult↗

PubMed1997

[Antinuclear antibody screening by an enzyme-linked immunosorbent assay using multiple nuclear antigens].

We assessed the clinical value of an enzyme-linked immunosorbent assay (ELISA) kit (MESACUP ANA, MANA) which uses multiple nuclear antigens for screening antinuclear antibody (ANA). Since the screening procedure for ANA by the indirect fluorescence method (FANA) requires trained personnel and gives rather subjective results, development of a suitable screening test for ANA by ELISA which uses specific nuclear antigens has been long awaited. Serum samples from 350 patients with connective tissue diseases (CTD), and from 300 normal subjects were assayed for ANA by ELISA and the results were compared with those of FANA and of single-antigen ELISAs for RNP, Sm, SS-A, SS-B, Scl-70, Jo-1, dsDNA, and ssDNA. For discrimination between patients with systemic lupus erythematosus and normal subjects, the sensitivity, specificity and accuracy for MANA were 85.7%, 97.5%, and 91.6%, and those for FANA were 95.8%, 77.0%, and 86.4%, respectively. Analysis of CTD sera showing discordant results between FANA and MANA using single-antigen ELISAs revealed that FANA - MANA + sera (n = 8) contained antibodies against SS-A (n = 1) or dsDNA (n = 3) or ssDNA (n = 3), and that some FANA + MANA - sera (n = 82), which were frequently found in RA patients (43/98, 43.9%), also contained antibodies against RNP (n = 3) or ssDNA (n = 13). MANA + normal sera (n = 9) were found to contain antibodies against SS-A (n = 1) or dsDNA (n = 1) or ssDNA (n = 2). In conclusion, MANA was found to be objective, much less labor intensive and suitable for screening large numbers of CTD sera for disease-specific ANAs.

Antibodies, Antinuclear↗