PubMed Health⌕ Search

Biomedical subjects

F Kayama

Publications and source records attributed to F Kayama.

34 records · Page 2Linked to original sources
PubMed1992

The effect of ethylene glycol monomethyl ether and diethylene glycol monomethyl ether on hepatic gamma-glutamyl transpeptidase.

In this paper, we determined whether ethylene glycol monomethyl ether (EGME) and diethylene glycol monomethyl ether (diEGME) induce hepatic gamma-glutamyl transpeptidase activity. Male adult Wistar rats weighing 220 g were used as experimental animals. EGME (100, 300 mg/kg per day) and diEGME (500, 1000, 2000 mg/kg per day) were administered by gavage for 1, 2 or 5 days or 4 weeks. In the 4-week study, experimental animals were administered EGME or diEGME once a day orally, 5 days/week. EGME treatment increased the serum gamma-glutamyl transpeptidase (GGT) level significantly, however, diEGME did not. The activities of three other enzymes (SGOT, SGPT and ALP) in serum were not altered by EGME or diEGME treatment and thus there was no biochemical indices of hepatic damage by EGME or diEGME. EGME treatment increased the GGT activities in the liver and lungs. Of the organs examined, the induction of GGT was the greatest in the liver. The inducibility in the liver was 216% for the 5-day treatment and 460% for the 4-week treatment. A dose-dependent increase of hepatic microsomal GGT activity by EGME was observed. On the other hand, renal GGT activities were declined to 72% and 60% of control by the 5-day and 4-week EGME treatments, respectively. DiEGME did not affect the GGT activities in any of the tissues except those of the brain. In the histochemical study, most hepatocytes at the periportal zones were stained with GGT staining after the 4-week treatment. However, the hepatocytes at the central zones were negative.

Animals↗
PubMed1991

Absorption of cadmium after a long-term oral administration of cadmium to dogs.

A long-term experiment using beagle dogs to investigate the absorption of cadmium was conducted. The dogs in the experimental groups were given a commercial diet and pelleted food containing 1, 3, 10, 50, and 100 mg of cadmium per day. The cadmium concentration in the blood increased continuously, gradually reaching a steady state following the administration of cadmium. The cadmium excreted daily in urine increased continuously. The cumulative excreted amount of cadmium in urine was calculated by using the trapezoidal rule based on the data of excretion of cadmium in urine. Then the absorbed fraction of administered cadmium was estimated on the basis of the relationship between the cumulative excreted amount of cadmium in urine and the cumulative administered dose of cadmium after the cadmium concentration in blood reached a steady state. The absorbed fraction of cadmium decreased with an increase in the administered dose of cadmium. A dose-dependent increase between the absorbed amount and the administered dose was observed.

Administration, Oral↗
PubMed1991

Selective depletion of immature thymocytes by oral administration of ethylene glycol monomethyl ether.

Although immunotoxicity of ethylene glycol monomethyl ether (EGME) has been strongly suspected, functional evaluation of the immune response in EGME-treated animals was negative in previous studies. We observed a decrease in thymic cellularity and increases in the various ex vivo immunological assays in mice, orally administered with EGME 0.5 or 1.0 mg/g body weight daily for 5 or 10 days: ex vivo lymphoproliferative responses to concanavalin A, in vitro induction of trinitrophenyl (TNP)-specific cytotoxic T-cell activity of thymocytes and splenocytes. Histopathological examination of the thymus of the treated mice disclosed a markedly atrophic cortex and almost intact thymic medulla. Study of thymocyte surface markers revealed that CD4+/CD8+, Thy-1+, PNA+ immature thymocytes were relatively decreased in EGME-gavaged mice and that, thus, ratios of CD4-/CD8+, H2+ mature thymocytes were enriched. These findings indicate that oral administrations of EGME selectively deplete immature thymocytes in mice. Although the mechanism of action remains unknown, the EGME-induced immature thymocyte depletion is not considered to be due to lymphocidal action of corticosteroids.

Administration, Oral↗
PubMed1991

Effects of dietary zinc deficiency on protein secretory functions of the mouse testis.

The effects of dietary zinc deficiency on testicular protein secretion, mainly that by Sertoli cells, were examined by electron microscopy and two-dimensional polyacrylamide gel electrophoresis of [35S] methionine-labeled secretory proteins from mouse testes. Zinc deficiency caused a significant decrease in the gonadosomatic index and a distinct increase in deoxyribonucleic acid concentration. Sertoli cells maintained normal fine-structural features; junctional complexes among Sertoli cells continued to divide seminiferous tubules into basal and adluminal compartments in the zinc-deficient mouse testes. Severe atrophic changes were observed in spermatogenic cells after meiotic division in the adluminal compartment, but not in spermatogonia located in the basal compartment. Zinc replacement treatment caused spermatogenesis to recover normally. Although total protein secretion was not affected by zinc deficiency, one polypeptide spot appeared due mainly to the loss of its target spermatogenic cells. The present study indicates that zinc is indispensable for spermatogenic cells after meiosis and that testicular protein secretory functions can be preserved in the absence of zinc.

Animals↗
PubMed1990

Effect of ethylene glycol monomethyl ether and diethylene glycol monomethyl ether on hepatic metabolizing enzymes.

Glycol ethers have been extensively used in industry over the past 40-50 years. Numerous studies on the toxicity of glycol ethers have been performed, however, the effects of glycol ethers on the hepatic drug metabolizing enzymes are still unknown. We studied the changes of the putative metabolic enzymes, that is, the hepatic microsomal mixed function oxidase system and cytosolic alcohol dehydrogenase, by the oral administration of diEGME and EGME. Adult male Wistar rats were used. DiEGME was administered orally; 500, 1000, 2000 mg/kg for 1, 2, 5 or 20 days and EGME was 100, 300 mg/kg for 1, 2, 5 or 20 days. Decreases in liver weights were produced by highest doses of diEGME (2000 mg/kg body wt/day for 20 days) and EGME (300 mg/kg body wt/day for 20 days). DiEGME increased hepatic microsomal protein contents and induced cytochrome P-450, but not cytochrome b5 or NADPH-cytochrome c reductase. The activity of cytosolic ADH was not affected by diEGME administration. On the other hand, EGME did not change cytochrome P-450, cytochrome b5 or NADPH-cytochrome c reductase. The activity of cytosolic ADH was increased by repeated EGME treatment. Therefore it is suspected that the enzyme which takes part in the metabolism of diEGME is different from that of EGME, although diEGME is a structural homologue of EGME.

Administration, Oral↗
PubMed1989

[Continuing education and residency program of occupational medicine in U. S. A].

To investigate postgraduate education of occupational medicine in the U. S. A., the author was sent to take some courses in occupational medicine continuing education supported by the National Institute of Occupational Health (NIOSH) in February and March of 1988. The course participants were mainly industrial hygienists. The contents of the courses were approximately the same as those of the Three-Month Course in Fundamental Occupational Health held in UOEH for medical doctors. The physicians in occupational medicine in the U. S. A. take mainly mini-residency courses from the NIOSH programs. The Curriculum of the Intensive Residency Program at the University of California San Francisco (UCSF) is presented in this report as a reference. According to the information I acquired, well-trained industrial hygienists are maintaining a high standard of control over the workplace environment. I received the impression that the industrial hygienists are playing an important part in occupational health in the U. S. A. Physicians specializing in occupational medicine are interested more in the clinical diagnosis of occupational diseases than in preventive measures such as environmental control of the workplace.

Curriculum↗
PubMed1989

Significance of cardiovascular malformations in cystic hygroma: a new interpretation of the pathogenesis.

Fetuses with cystic hygroma or loose skin of the neck were studied chromosomally and phenotypically to clarify the relation between neck abnormality and cardiovascular malformations. Of 12 fetuses, 9 had chromosome abnormalities: 4 with 45,X, 3 with trisomy 21, one each with trisomy 13, dup 6q. One had normal chromosomes. Two cases, in which chromosome analysis was unsuccessful, were morphologically suspected to be trisomy 13. Nine of the 12 fetuses had either bilateral cystic hygroma of the neck (7 cases) or nuchal bleb (2 cases: trisomy 13 and dup 6q). Two of the 3 remaining cases (trisomy 21) had loose skin of the neck, and one had edematous swelling of the skin of the neck. Except for the last case of trisomy 21, 11 fetuses (91.7%) had severe and/or rare cardiovascular malformations. They were divided into 3 major groups: a) spectrum of hypoplastic left heart syndrome (45,X and dup 6q), b) double outlet right ventricle, agenesis of semilunar valve (trisomy 13), and c) abnormality of atrioventricular orifice or valves (trisomy 21). One fetus with normal chromosomes had persistent left superior vena cava instead of absent right one and calcification of myocardium. Histological observation of edematous skin demonstrated the abnormal distribution of lymph vessels, including their absence. Some cases showed hypoplastic thymus. To integrate the findings of the present study and the descriptions in the literature, a pathogenesis is hypothesized in relation to migration of neural crest cells and extracellular matrix.

Abnormalities, Multiple↗
PubMed1988

[Neonatal hyperbilirubinemia of inadequately breast-fed infants and the effect of formula supplementation].

One hundred and fifty full-term breast-fed infants were analysed for their oral intake in the first 6 days. Fifty infants with less than 330 ml/kg/6 days breast feeding were defined as inadequately breast-fed infants. Twenty inadequately breast-fed infants without formula supplementation had significantly lower total fluid intake, lower total calorie intake, more body weight loss and significantly higher rates of hyperbilirubinemia and requirement of phototherapy when compared with the control group of 100 infants with more than 330 ml/kg/6 days breast feeding. On the other hand, 30 inadequately breast-fed infants with formula supplementation had significantly higher total fluid intake, higher total calorie intake, lower body weight loss and requirement of phototherapy than those without formula supplementation. From these data, we suggest that (1) Inadequate feeding may be a factor responsible for the higher prevalence of early neonatal jaundice in breast-fed infants reported in the literature. (2) Lower fluid intake, lower calorie intake and greater body weight loss may be associated with the higher incidence of hyperbilirubinemia and requirement of phototherapy. (3) Formula supplementation may be helpful in decreasing the risk of hyperbilirubinemia in inadequately breast-fed infants.

Breast Feeding↗
PubMed1985

[Reliability of the advice given at genetic counselling: follow-up study].

A follow up investigation was carried out in order to estimate the reliability of the advice given at our genetic counselling clinic. Data were collected mainly by questionnaires sent by mail in November, 1983 to 556 clients counselled during the period January, 1976 - December, 1982. The outcome of 444 pregnancies for 361 clients was revealed. They were divided into three groups according to the risks estimated and suggested by the counsellors; below 2% (Group I), 2 - 9% (Group II) and 10% or more (Group III). The following results were obtained. The incidence of those who had not become pregnant following the day of counselling was higher in Groups II and III than in Group I. The rate of spontaneous abortion was higher in Group III than in Groups I and II. The incidence of pregnancies with children affected by birth defects for which the risks were estimated was 1.5% in Group I, 6.5% in Group II and 26.5% in Group III. Six to nine percent of babies of all groups suffered from other diseases such as intrauterine fetal death, congenital anomalies, developmental abnormalities or severe infectious diseases. The recurrence rate for regular trisomic Down's syndrome was 1.8%. These results suggested that the risk estimates and advice were quite reliable and helpful.

Abortion, Spontaneous↗
PubMedDate not supplied

Estrogenic xenobiotics affect the intracellular activation signal in mitogen-induced human peripheral blood lymphocytes: immunotoxicological impact.

The present study was an attempt to elucidate the effect of estrogenic xenobiotics on the proliferation of mitogen-stimulated human peripheral blood lymphocyte (PBL). Our findings follow: (a) the proliferation of PBL in response to phytohemagglutinin (PHA) was mediated by protein kinase C activity, but estrogenic xenobiotics had a strong inhibitory effect on protein kinase C activity of PHA-stimulated PBL; (b) cytoplasmic extracts from PHA-stimulated PBL greatly activated DNA replication, but estrogenic xenobiotics had a strong inhibitory effect on these activities. The results suggest that the cytoplasmic signal-generating system in mitogen-treated PBL is inhibited by estrogenic xenobiotics, and that the defect occurs at all stages in the sequence of events leading to DNA synthesis and cell proliferation.

Adult↗
PubMedDate not supplied

Squamous cell carcinoma arising in a mature teratoma with metastasis to the urinary bladder.

We describe a patient with squamous cell carcinoma arising in a mature teratoma. Magnetic resonance (MR) images revealed a solid lobulated mass attached to the ovarian cyst containing a fat-fluid level. The solid component with extension into pelvic fat showed as hypointensity on T2-weighted MR images with good enhancement. A metastatic tumor to the urinary bladder was also demonstrated.

Carcinoma, Squamous Cell↗