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Biomedical subjects

R Nakayama

Publications and source records attributed to R Nakayama.

At least 73 records · Page 4Linked to original sources
PubMed1988

Study of the effect of an anti-androgen (oxendolone) on experimentally induced canine prostatic hyperplasia. I. Morphological analysis.

To investigate the effect of anti-androgens on BPH, Oxendolone (OXD), a pure anti-androgen, was tested in experimentally induced BPH in 17 beagle dogs, alone or in combination with medroxyprogesterone acetate (MPA) which displays both anti-androgenic and anti-estrogenic activity. The relatively early stage of canine BPH was induced by administration of 3 alpha-androstanediol (3 alpha-A) plus estradiol (E2) for 6 months and followed by testosterone propionate (TP) plus E2 for another 6 months during the anti-androgenic treatment. By the manipulation with T, a decrease in volume of glandular component associated with a relative increase in stromal tissue was achieved, which mimics human BPH histology. The prostate substituted with T and E2, however, gradually decreased in size. Therefore the effect of OXD or OXD + MPA was not significant against the untreated controls (T-E control). The weight of the prostate in these OXD +/- MPA groups was however significantly reduced as compared to that of BPH controls which received 3 alpha-A and E2 throughout the experimental period. On histological examination, atrophic changes were observed in the hormone-treated groups compared to the T-E control. The finding was the most striking in the OXD + MPA group with small non-involuted acini scattered in the abundant stomal tissue. This was almost identical to the appearances of castrated control groups. Atrophy may be due not only to the anti-androgenic but also to the anti-estrogenic property of MPA. A report on the hormonal background of this experiment will appear in the second article.

Androstane-3,17-diol↗
PubMed1988

Study of the effect of an anti-androgen (oxendolone) on experimentally induced canine prostatic hyperplasia. II. Endocrinological analysis.

The results of hormonal investigation of effects of an antiandrogen, Oxendolone (OXD), alone or in combination with medroxyprogesterone acetate (MPA), on experimentally induced canine BPH are reported. Seventeen beagle dogs were divided into 5 groups: 2 castrate controls for Group 0, 3 BPH controls for Group 1 which received 3 alpha-androstanediol (3 alpha-A) and estradiol (E2) for one year, and 12 dogs consisting of 3 groups which received 3 alpha-A and E2 for 6 months followed by testosterone propionate (TP) and E2 for another 6 months. The last 3 groups were treated with either 200 mg/week of OXD (Group 3) or OXD + 30 mg/week of MPA (Group 4), and otherwise untreated with these hormones (Group 2, T-E controls). On the blood hormone analysis, both T and 5 alpha-dihydrotestosterone (DHT) were generally lowered in the T-E administered groups (Group 2, 3 and 4) compared to those in Group 1. While MPA significantly decreased these androgen levels, OXD did not influence at all. The concentrations of E2 were similar. Although T content in the prostate did not differ significantly within the experimental groups, DHT was the highest in Group 1 and the lowest in Group 4 and was nearly the same level to Group 0. MPA reduced tissue DHT content but OXD did not. In the receptor assay study, nuclear androgen receptor (AR) content in Group 3 and 4 was significantly lower than that in Group 1. No obvious decrease in nuclear AR content could be seen among the other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Repression of pentose phosphate pathway dehydrogenase synthesis and mRNA by dietary fat in rats.

We have studied the effects of polyunsaturated fatty acid and its metabolism on the activity, relative synthesis and mRNA levels for rat hepatic glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD). Rats were meal-fed high carbohydrate diets containing either no fat, 5% safflower oil or 5% safflower oil + eicosa-5,8,11,14-tetraynoic acid (TYA). Hepatocytes were isolated and used as a source of RNA, de novo radiolabeled protein and postmitochondrial supernatant for enzyme assay. Dietary safflower oil, as a source of linoleic acid, repressed G6PD activity, synthesis and mRNA levels two- to threefold without significantly changing the amount of carbohydrate consumed. Similar but smaller changes were observed for 6PGD. Dietary fat + TYA (an analogue of arachidonate that inhibits normal metabolism of linoleic acid) prevented the fat-dependent lowering of G6PD and 6PGD activity, synthesis and mRNA levels. Our results suggest that a metabolite of linoleic acid regulates the activity of two lipogenic enzymes, G6PD and 6PGD, by lowering gene expression or mRNA processing or stability.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1988

Study on reaction of subpapillary venous plexus in patients with arterial occlusive diseases of lower extremity by reflective spectrophotometry.

The reactions of the subpapillary venous plexus were observed by analyzed fractional blood volume of tissue (Vb) in patients with arterial occlusive diseases, Fontaine's stage I-II, using the reflective spectrophotometer. The sole skin of 11 normal subjects, 17 patients with arteriosclerosis obliterans (ASO), and 14 patients with thromboangiitis obliterans (TAO) were scanned by the light reflectance of four specially selected wavelengths, including isobestic points (586 and 569 nm) and peaks in the spectra of oxyhemoglobin and deoxyhemoglobin (577 and 560 nm) in referring to time. Sampling area was the subpapillary venous plexus histologically because the depth for receiving reflectance is about 1.0 mm from the sole skin surface. One series observations was divided into five steps depending on the modes of combination of the applied pressure to ankle cuff and tilting. The Kubelka-Munk equation was utilized to calculate blood volume (Vb). It is concluded that the patients with ASO might have a dysfunction, not of the subpapillary venous plexus, but of the venular valve, whereas patients with TAO might have a dysfunction of both the subpapillary venous plexus and venular valve.

Adult↗
PubMed1988

[A study on the definition of early breast cancer].

The most important factor in improving the survival rates of the patients with breast cancer is early detection. A high cure rate can be expected if the condition is discovered in early stage. There were 195 patients with primary breast cancer in our hospital from August 1978 to November 1986. Among 280 patients with breast cancer who received radical operations from July 1970 to November 1986, there were 50 patients (18%) with recurrence. Mammography and echography were effective for the diagnosis of infiltrating cancer smaller than 10mm in diameter as well as those between 11 and 20mm in diameter. None of the patients with non-infiltrating or infiltrating carcinomas smaller than 15 mm or smaller than 20 mm in diameter with negative nodes had recurrence. Consequently, at present we define early breast cancer as the lesions of pathologically noninfiltrating or infiltrating smaller than 15 mm in diameter, or infiltrating smaller than 20 mm in diameter with negative nodes.

Adenocarcinoma↗
PubMed1988

[Necessity of adjuvant therapy after radical mastectomy based on a study of patients with negative nodes, who have recurrent breast cancer].

The status of the regional lymph nodes influences the prognosis of women with breast cancer who have received a radical mastectomy. To investigate the characteristics of patients with negative nodes who have had a recurrent breast cancer, a statistical study has been carried out involving 279 women who had received a radical mastectomy in our hospital from July 1970 to October 1986. From this study we conclude that systemic adjuvant therapy after radical mastectomy is necessary for patients with negative nodes who have had a breast cancer greater than 2.1 cm (T2) in diameter or a solid-tubular carcinoma.

Adult↗
PubMed1987

Existence of endogenous inhibitors of platelet-activating factor (PAF) with PAF in rat uterus.

Two kinds of phospholipids in normal rat uterus were found to inhibit the aggregation of washed rabbit platelets induced by 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine (alkylacetyl-GPC) and were named Inhibitor I and Inhibitor II and identified by mass spectrometry. Inhibitor I was a mixture of 1-acyl (16:0, 18:0, 18:1, 18:2, and 20:4)-2-lyso-sn-glycero-3-phosphocholine (acyllyso-GPC) and 1-alkyl (16:0, 18:0, and 18:1)-2-lyso-sn-glycero-3-phosphocholine (alkyllyso-GPC). 16:0 acyllyso-GPC was the most inhibitory, followed by 18:1, 18:2, 20:4, and 18:0 acyllyso-GPCs and 16:0 alkyllyso-GPC. Their IC50 values were in the range of 1-4 X 10(-5) M against the platelet aggregation induced by 1 X 10(-10) M 16:0 alkylacetyl-GPC, indicating that they were about 100 times weaker inhibitors than CV-3988. Inhibitor II was a mixture of N-acyl sphing-4-enyl phosphocholine (18:1/18:0, 18:1/20:0, 18:1/24:0, and 18:1/24:2). The most inhibitory of these components were 18:1/20:0 and 18:1/24:0, followed by 18:1/24:2 and 18:1/18:0, and their IC50 values were in the range of 4-5 X 10(-5) M against platelet aggregation induced by the alkylacetyl-GPC. Quantitatively, about 10(5) times higher concentrations of these inhibitors should be necessary to inhibit platelet aggregation induced by 1 X 10(-10) M 16:0 alkylacetyl-GPC. In fact, the contents of Inhibitors I and II, respectively, were approximately 10(5) times (4.7 X 10(-2) and 7.1 X 10(-2) mol/mol lipid-phosphorus of the original uterine phospholipids) than that of 16:0 alkylacetyl-GPC (1.4 X 10(-6) mol/mol lipid-phosphorus). The role of alkylacetyl-GPC in normal rat uterus is uncertain, but it coexists in situ with two kinds of endogenous inhibitors, choline containing lysoglycerophospholipids and sphingophospholipids.

Animals↗
PubMed1987

31P in-vivo spectroscopic study by high-field whole-body MR system--an application to a case with arteriosclerosis obliterans.

31P in-vivo spectroscopy was performed by a 1.5-tesla whole-body MR system. The 31P spectrum for the calf muscle in a patient with arteriosclerosis obliterans having intermittent claudication was obtained every two minutes. When the spectrum after the workload was compared with that at rest, an increase in inorganic phosphate (Pi) and a decrease in phosphocreatine (PCr) were observed, resulting in a strong decrease in the PCr/Pi ratio. This method can measure the ischemic and recovery stages of energy metabolism in skeletal muscle noninvasively and continuously in addition to magnetic resonance imaging.

Aged↗
PubMed1986

Metabolism of prostaglandins D2 and F2 alpha in primary cultures of rat hepatocytes.

3H-Labeled prostaglandins D2 and F2 alpha rapidly degraded to more-polar metabolites in primary cultured rat hepatocytes. The metabolites of prostaglandins D2 and F2 alpha accumulated in the culture medium. The metabolites extracted by ethyl acetate at pH 3 were purified by silicic acid column and thin-layer chromatography of silica gel, and were analysed by gas chromatography-mass spectrometry. The major metabolites from prostaglandin D2 were identified as dinor-prostaglandin D1 (7 alpha,13-dihydroxy-9-ketodinorprost-11-enoic acid) and tetranor-prostaglandin D1 (5 alpha,11- dihydroxy-7-ketotetranorprost-9-enoic acid). Those from prostaglandin F2 alpha were identified as dinor-prostaglandin F1 alpha (7 alpha,9 alpha,13-trihydroxydinorprost-11-enoic acid), tetranor-prostaglandin F1 alpha (5 alpha,7 alpha,11-trihydroxytetranorprost-9-enoic acid) and 9 alpha,11 alpha,15-trihydroxyprost-13-ene-1,20-dioic acid. These data indicate that prostaglandins D2 and F2 alpha mainly degraded by beta-oxidation, which is the same process as reported earlier for prostaglandins E1 and E2, and that prostaglandin F2 alpha was also subjected to omega-oxidation.

Animals↗
PubMed1986

Haemodynamic effects of intra-arterial and intravenous administration of prostaglandin E1 in patients with peripheral arterial disease.

The purpose of this study was to compare the haemodynamic effects of intra-arterial and intravenous prostaglandin E1 (PGE1) both injected and infused into ischaemic legs. Continuous intra-arterial infusion of PGE1 induced a significantly greater increase in skin temperature and blood flow than did intravenous drip infusion. Furthermore, intra-arterial infusion caused no steal phenomenon in the toe as indicated by skin temperature. On the other hand, toe skin temperature decreased during intravenous drip in 33 per cent of the legs tested. Continuous intravenous infusion also produced a significantly greater increase in toe skin temperature than did brief intravenous drip. In three of ten ulcers healed by continuous intra-arterial infusion, no definitive effect was obtained from continuous intravenous infusion even when it was repeated up to three times before continuous intra-arterial infusion. Intra-arterial injection of PGE1 caused no significant increase in toe skin temperature.

Adult↗
PubMed1986

Hydrops fetalis secondary to Bart hemoglobinopathy.

Alpha-thalassemia is the most common cause of hydrops fetalis among Southeast Asians. With the recent influx of Southeast Asian refugees and the rapidly growing Filipino population this will become an increasingly important obstetric problem in the United States. Homozygous alpha-thalassemia, or Bart hemoglobinopathy, is invariably fatal to the fetus and produces significant maternal morbidity. Eighteen cases of homozygous alpha-thalassemia in one hospital are reviewed. This is the largest series reported in the United States. Recommendations are made for antenatal screening, diagnosis, and management of alpha-thalassemia.

Adult↗