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Biomedical subjects

H Miyauchi

Publications and source records attributed to H Miyauchi.

At least 37 records · Page 2Linked to original sources
PubMed1999

[A case of myotonic dystrophy showing proximal dominant muscle involvement but not myotonia].

A 45-year-old female had progressive difficulty in climbing stairs and standing from a chair for 10 years. She had binocular cataracts which were operated at the age of 42 years. On examination, she had marked muscle wasting in the proximal limbs, scapular and sternomastoid muscles. She presented as marked muscle weakness in the proximal portion of the lower extremities and moderate in the upper extremities and the legs. Deep tendon reflexes were absent in all limbs. There was no grip myotonia, or percussion myotonia of the thenar muscle and tongue. Myotonia was not elucidated even after the hands were exposed to cold water. Moreover, none of the examined muscles revealed insertion myotonic discharge on electromyography. Serum CK level was normal and IgG value decreased to 546 mg/dl. Muscle biopsy of the left biceps muscle showed the variation in fiber size, increased central nuclei and many fiber with pyknotic nuclear clumps on HE staining. Sarcoplasmic mass and ring fibers were also found on HE staining. There were a few percents of ragged-red fibers on Gomori-trichrome staining, and type 1 fiber atrophy was found on pH 4.5 ATP-ase staining. The expansion of lymphocyte CTG trinucleotide repeats in the myotonin protein kinase gene was about 733, so that she was diagnosed as having myotonic dystrophy (MD). MRI of skeletal muscles exhibited marked atrophy especially in the femoral region and the biceps muscle. This patient had the proximal dominant muscle weakness, and absent myotonia even on electromyographic examination, which are unusual clinical features of adult onset MD.

Atrophy↗
PubMed1998

Bovine lactoferrin stimulates the phagocytic activity of human neutrophils: identification of its active domain.

Bovine LF (bLF) at concentrations in the range of 50-250 micrograms/ml enhanced the phagocytic activity of human neutrophils as determined by measuring the incorporation of FITC-labeled latex beads by flow cytometry. The stimulatory effect of bLF was not abrogated by hydrolysis with pepsin. Bovine lactoferricin (bLFcin), which is a bactericidal fragment purified from a pepsin hydrolysate of bLF (bLFH), also enhanced the phagocytic activity, whereas, in contrast, the fraction of bLFH depleted of bLFcin showed no stimulatory effect. The phagocytosis-enhancing activity of bLF still remained after washing the neutrophils, following exposure to bLF. Also, bLF pretreatment of the latex beads stimulated their uptake. These results demonstrate that bLF is effective in promoting the phagocytic activity of human neutrophils. This activity appears to be due to its bLFcin domain and may involve dual mechanisms of direct binding to neutrophils and opsonin-like activity.

Animals↗
PubMed1998

A compact molecular-beam epitaxy apparatus for in situ soft X-ray magnetic circular dichroism experiments.

An economical and easily movable molecular-beam epitaxy (MBE) apparatus which prepares magnetic ultrathin films and superlattices with atomically well controlled interfaces has been designed and constructed. Cleaning and characterization of substrates, sample deposition in a layer-by-layer fashion, and characterization of samples both during and after growth can be carried out in a single ultrahigh vacuum (UHV) chamber. This MBE apparatus is combined with UHV high-field magneto-optical instruments for in situ soft X-ray magnetic circular dichroism experiments on two-dimensional magnetic systems.

Journal Article↗
PubMed1998

Evidence on N-acetyltransferase allele-associated metabolism of hydrazine in Japanese workers.

Hydrazine (N2H4), which has been categorized as a weak carcinogen, is a chemical with the one of the largest production rates in Japan. We have investigated the effects of acetylation phenotypes on the metabolism of hydrazine. Genotypes of N-acetyl transferases, NAT2*, were determined using polymerase chain reaction for 297 male workers. Biological and exposure monitoring were also conducted. The rapid and intermediate acetylators accounted for 45% each, and the slow acetylators accounted for 10%. Biological half-lives were significantly different among the three acetylation phenotypes (analysis of variance, P < 0.05): 3.94+/-1.70 hours for slow acetylators, 2.25+/-0.37 hours for intermediate acetylators, and 1.86+/-0.67 hours for rapid acetylators. Among Japanese, rapid and intermediate acetylators are the major phenotypes, which is in sharp contrast with those among Caucasians. We conclude that biological monitoring should take genetic factors, which may vary dramatically among different populations, into account.

Adult↗
PubMed1998

The contribution of trace elements from smokeless powder to post firing residues.

The smokeless powders in 22 kinds of ammunitions seized from one of the Japanese gang groups were analyzed by scanning electron microscopy/energy dispersive X-ray microanalysis (SEM/EDX). Copper(Cu), sulfur(S), potassium(K), silicon(Si), aluminum(Al), calcium(Ca), iron(Fe), chlorine(Cl), and barium(Ba) were detected. Cu was found in all samples. One sample contained a high amount of Ba. One part of the burnt smokeless powder was found to contain Cu, K, Ca, Fe and S, the other part contained Cu, Fe, and zinc(Zn). It has been reported that the elements in gunshot residues originate from a bullet and/or a primer. However, this demonstrates that smokeless powder could be the source of some of the elements detected.

Aluminum↗
PubMed1998

A cross-sectional observation of the health effects of hydrazine hydrate and differences of its metabolism by NAT2 polymorphism.

OBJECTIVES: To summarize the results of two studies that attempted to clarify: (1) the health effects of hydrazine hydrate (HH) (N2H4 x H2O: CAS No. 7803-57-8); and (2) the influence of allelic polymorphism of N-acetyltransferase (NAT2) on the metabolism of HH. METHODS: A cross-sectional survey was carried out on 172 male HH-exposed workers and 125 male referent workers at five factories in Japan. The biological half-lives of HH after 1 h of exposure were determined in 12 workers, four workers in each of three NAT2 phenotypes. Clinical examinations were performed and acute and chronic subjective symptoms related to HH were examined by self-administered questionnaires. NAT2 phenotypes were assessed. RESULTS: No hydrazine was detected in either the breathing zones or the urine of the referent workers. The mean hydrazine concentration in the breathing zones, hydrazine and acetylhydrazine in urine, and the cumulative exposure level were 0.0109 ppm, 0.8660 micromol/g x Cr, and 2.80 ppm-years, respectively. There was no difference and no dose-dependent change in the health examination items between HH-exposed and referent workers after adjusting confounding factors, nor in terms of the differences of NAT2 phenotypes. Of 90 subjective symptoms, complaints of nightmares were significantly related to HH exposure. The half-life of urinary hydrazine and acetylhydrazine on rapid, intermediate, and slow phenotypes was 1.68, 3.01, and 4.46 h, respectively. CONCLUSION: This study suggested that current and cumulative exposure to HH did not affect the workers' health, and the half-life of the slow phenotype was longer than those of the rapid and intermediate phenotypes.

Adolescent↗
PubMed1997

Lactoferrin as a suppressor of cell migration of gastrointestinal cell lines.

The effects of lactoferrin (Lf), an iron-binding glycoprotein, on cell migration were investigated. Lf inhibited the cell migration of three gastrointestinal cell lines (Caco-2 cells, AGS cells, and IEC-18 cells) in vitro. Both iron-saturated (holo) and iron-depleted (apo) Lf showed this inhibitory effect. Chelation of iron in the culture medium by desferrioxamine did not affect the activity of either form of Lf. A pepsin hydrolysate of Lf exhibited effectiveness similar to that of intact Lf. These results demonstrate a novel activity of Lf and suggest a potential role for this molecule in gastrointestinal wound healing, which is independent of its iron-binding capacity.

Adenocarcinoma↗
PubMed1997

Beta-lactoglobulin suppresses melanogenesis in cultured human melanocytes.

The effects of whey proteins from bovine milk on melanogenesis in cultured human melanocytes were examined. Among the major protein components of milk whey including beta-lactoglobulin (BLG), alpha-lactalbumin, serum albumin, and IgG, only BLG exhibited the depigmenting effect at a concentration of 1 mg/ml. Also, BLG suppressed the activity of tyrosinase in these cells. Retinol, to which BLG is known to bind, slightly increased the pigmentation of the cells at concentrations in the range of 1-100 nM, and retinoic acid, a metabolite of retinol, exhibited a strong pigmentation-promoting effect within the same concentration range. Treatment of the cells with 1 mg/ml BLG completely abrogated the pigmentation induced by these A vitamins. These results demonstrate a novel biological activity of BLG and suggest that this activity is dependent on its ability to bind retinol.

Animals↗
PubMed1997

Pharmacological properties of YM17E, an acyl-CoA:cholesterol acyltransferase inhibitor, and diarrheal effect in beagle dogs.

YM17E (1,3-bis[[1-cycloheptyl-3-(p-dimethylaminophenyl)ureido]methyl]ben zene dihydrochloride) was found to be a potent inhibitor of acyl-CoA:cholesterol acyltransferase (ACAT) in rabbit liver and intestine microsomes. Dixon plot analysis revealed that YM17E inhibited microsomal ACAT in a non-competitive manner. YM17E induced a marked decrease in serum cholesterol, especially in non-high-density lipoprotein (HDL) fractions, in cholesterol-fed rats and rats fed normal chow. Measurement of bile secretion after oral administration of YM17E in cholesterol-fed rats showed that the drug markedly accelerated the secretion of bile acids and neutral sterols. Furthermore, absorption of [3H]cholesterol from the gut of cholesterol-fed rats was significantly inhibited by YM17E. From these results, the hypocholesterolemic activity of YM17E in these animals resulted from both a decrease in cholesterol absorption from the gut and the stimulation of excretion of cholesterol from the liver into bile. However, YM17E caused secretory diarrhea in beagle dogs at near lipid lowering doses. When YM17E was administered at the same total dosage but divided into 5 daily administrations, the incidence of diarrhea was significantly reduced while its cholesterol lowering effect became stronger. These results suggest that the inhibition of intestinal and/or liver ACAT increases the risk of diarrhea development which, however, can be avoided by controlled drug administration in beagle dogs.

Animals↗
PubMed1997

Immunomodulatory effect of bovine lactoferrin pepsin hydrolysate on murine splenocytes and Peyer's patch cells.

The effects were examined of a pepsin hydrolysate of bovine lactoferrin on the proliferation of murine splenocytes. The hydrolysate enhanced [3H]thymidine uptake by splenocytes, but undigested bovine lactoferrin exerted an inhibitory effect. The hydrolysate had the ability to inhibit the blastogenesis that was induced by mitogens such as concanavalin A, phytohemagglutinin, and lipopolysaccharide; inhibition was similar to that with undigested lactoferrin. These results suggested that the hydrolysate contained both immunostimulatory and immunoinhibitory peptides. The stimulatory effect of the hydrolysate in the absence of mitogens was then explored in more detail using nonadherent splenocytes. The proliferative response of splenocytes to the hydrolysate was much greater in the fraction that was enriched with B cells than in the fraction that was enriched with T cells. The hydrolysate did not affect thymocyte proliferation. These data indicated that the adherent cells resembling macrophages and found among the splenocytes were not the target cells of the hydrolysate. The stimulatory effect of the hydrolysate was due to the activation of B cells by the hydrolysate and enhanced immunoglobulin production by splenocytes. Because the hydrolysate also enhanced the proliferation and immunoglobulin A production of Peyer's Patch cells, the immunostimulatory effect of the hydrolysate in vivo was examined using mice that had been orally immunized with cholera toxin. The concentrations of immunoglobulin A conjugated against cholera toxin in bile and in the intestinal contents of mice fed liquid diets containing 1% (wt/vol) lactoferrin hydrolysate were greater than those of mice fed control diets. This result suggested that the use of the lactoferrin hydrolysate is beneficial to enhance mucosal immunity.

Adjuvants, Immunologic↗
PubMed1996

Resection of the inferior head of the pancreas: report of a case.

We developed a new technique for partial resection of the head of the pancreas with an end-to-side pancreaticoduodenostomy, while preserving the duodenum, the common bile duct, and the upper part of the head of the pancreas around the duct of Santorini. A resection of the inferior head of the pancreas was performed in a patient with an intraductal mucin-producing tumor of the pancreas. This procedure is considered to be appropriate for treating both benign disease and noninvasive malignant disease involving either the uncinate process or the duct of Wirsung, because it removes both the uncinate process and the pancreatic tissue around the duct of Wirsung. We thus believe that a resection of the inferior head of the pancreas with an end-to-side pancreaticoduodenostomy can help play a significant role in the management of patients with benign diseases and localized malignant tumors of the pancreas.

Adenocarcinoma, Papillary↗
PubMed1996

Synthesis and antifungal activity of alkylthio and alkylsulfonyl derivatives of SM-8668.

Triazole analogues which contained alkylthio or alkylsulfonyl groups where synthesized as derivatives of antifungal SM-8668 and estimated for their in vitro and in vivo activity. Derivatives having pentylthio, heptylthio or nonylthio groups showed excellent efficacy against both candidiasis and aspergillosis. Introduction of a hydrophilic group at the end of their alkyl chain made their activity stronger. Especially, 5-hydroxypentylthio and 7-hydroxyheptylthio derivatives showed the strongest antifungal activity.

Alkylation↗
PubMed1996

Kappa-casein suppresses melanogenesis in cultured pigment cells.

The effects of bovine milk proteins on melanogenesis in B16 cells were examined. Both whey protein isolate and casein exhibited depigmenting properties. Among the major protein components of milk--including beta-lactoglobulin, alpha-lactalbumin, alpha-, beta-, and kappa-casein--only kappa-casein exhibited the depigmenting effect. However, the carboxyl terminal peptide of kappa-casein, glycomacropeptide, did not show this activity. Also, kappa-casein promoted the proliferation of the cells and inhibited the activity of tyrosinase in the cells. These results indicate that kappa-casein acts as a melanogenesis-suppressing modulator.

Animals↗
PubMed1996

Structure-activity relationships of 3-methyl and 3,3-dimethyl analogs of 2-(2,4-difluorophenyl)-3-(omega-substituted alkyl)sulfonyl-1-(1H-1,2,4-triazol-1-yl)-2-propanols.

3-Methyl and 3,3-dimethyl analogs of 2-(2,4-difluorophenyl)-3-(omega-substituted alkyl)sulfonyl-1-(1H-1,2,4-triazol-1-yl)-2-propanols were synthesized and evaluated for their antifungal activities against Candida albicans and Aspergillus fumigatus. The 3,3-dimethyl analogs were found to have more potent activity both in vitro and in vivo than the corresponding 3-mono-methyl analogs. The prophylactic efficacy of the lead compounds against murine systemic candidiasis and aspergillosis was improved significantly by dimethylation of the 3-position.

Animals↗