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Biomedical subjects

Y Yoshimura

Publications and source records attributed to Y Yoshimura.

At least 541 records · Page 30Linked to original sources
PubMed1986

Preparation of 1-acyloxyethyl esters of 7-[2-(2-aminothiazol-4-yl)acetamido]-3-[[[1-(2-dimethylaminoe thy l)-1H-tetrazol-5-yl]thio]-methyl]ceph-3-em-4-carboxylic acid (cefotiam) and their oral absorption in mice.

In a separate study on the orally active acyloxymethyl esters (1) of 7-[2-(2-aminothiazol-4-yl)acetamido]-3-[[[1-(2-dimethylaminoethyl) - 1H-tetrazol-5-yl]thio]methyl]ceph-3-em-4-carboxylic acid (cefotiam, CTM), we have shown, by quantitative structure-oral bioavailability (BA) relation analysis, that the R2 group in the acyl group R2CO must have both an adequate lipophilicity (Hansch's lipophilic parameter, pi) and steric hindrance (Taft's Es value). However, to satisfy these requirements, a complex alkyl group R2 must be employed, the ester of which is difficult to synthesize and has unique metabolic fate. In this study, we selected and prepared the 1-acyloxyethyl esters (2) of CTM instead of 1 to avoid R2 groups that are too complicated. We found that the esters (2) gave improved oral BAs over 1: the 1-(3-methyl-valeryloxy)ethyl ester (2h) showed the highest peak plasma CTM level (Cmax) comparable to that obtained after subcutaneous injection of CTM. The 1-(cyclohexylacetoxy)ethyl ester (2t), the 1-(2-ethylbutyryloxy)ethyl ester (2j), and 2h showed BAs near 100%. For these esters (2), good correlations were also observed among the pi, the Es values of R2, and the log Cmax and log BA in the analysis of the quantitative structure-oral bioavailability relation: an ester having an alkyl group as R2 with a pi value of 3.07 or 3.08 and a Es value of -1.04 or -1.29 gave the highest Cmax or BA, respectively. As expected, the optimal pi values are almost the same as those obtained with 1 but the optimal Es values are larger (Es = -2.07). Thus, it has been confirmed by preparing 1-acyloxyethyl esters (2) of CTM that the oral bioavailability of CTM can further be improved without preparing acyloxymethyl esters (1) with a complicated acyl group.

Administration, Oral↗
PubMed1986

[Study of chemotherapy in the field of internal medicine--clinical experience with SF-SP].

UNLABELLED: An SF-SP Tegafur spansule preparation was administered to 26 patients with advanced cancer (24 evaluable), and the clinical effectiveness and toxicity were studied. In most of cases, daily dosages of 800 mg were administered in two parts, in a few cases, daily dosages of 1,000 mg or 1,200 mg were given. Clinical effectiveness: The evaluation of effectiveness was based on the Koyama-Saito group criteria. Of the 24 evaluable cases, PR was observed in 3 cases of gastric cancer, one of colon cancer, and one of liver cancer, a total of 5 cases (20.8%). In these 5 cases the daily dosage was 800 mg, and the median duration of PR was 51 days. TOXICITY: TOXICITY was observed in 3 (11.5%) of the 26 cases.

Administration, Oral↗
PubMed1986

Synthesis of 2'-deoxy-6,3'-methano-cyclo-pyrimidine nucleosides.

The nucleophilic attack of lithiated pyrimidines to a suitably-protected 3-ketosugar, afforded the 3-branched sugar stereospecifically, followed by intramolecular glycosylation to give 6,3'-methano-cyclo-pyrimidine nucleosides. The 2'-deoxygenation was achieved by sequential protection, deprotection and radical reduction.

Indicators and Reagents↗
PubMed1985

Microvasculature of preovulatory follicles: comparison of in situ and in vitro perfused rabbit ovaries following stimulation of ovulation.

Perifollicular vasculature undergoes significant morphologic changes as ovulation approaches. These vascular changes were observed in in vitro perfused and in situ rabbit ovaries by means of scanning electron microscopy of microcorrosion casts. Casts were made in in situ unstimulated ovaries, in situ ovaries stimulated with human chorionic gonadotropin, in vitro perfused unstimulated ovaries, and in vitro perfused ovaries after an ovulation-inducing dose of human chorionic gonadotropin, prostaglandin F2 alpha, histamine, or norepinephrine. Dilated vessels, extravasation of resin from weakened vessels, and filling defects at the apex of the follicle were observed in in situ ovaries 9 to 12 hours after stimulation and in in vitro perfused ovaries 4 to 6 hours after human chorionic gonadotropin. In vitro perfused ovaries stimulated with prostaglandin F2 alpha or histamine demonstrated dilated capillaries with extravasation of the resin and filling defects at the apex of large follicles. Norepinephrine-stimulated ovaries showed incomplete filling of vessels, although some large follicles showed extravasation of resin. The occurrence of dilated vessels, extravasation of resin, and filling defects is indicative of preovulatory vascular changes in both in situ and in vitro perfused ovaries, regardless of the ovulatory stimulus.

Animals↗
PubMed1985

The role of calcium in the induction of refractoriness to cyclic AMP stimulation by TSH.

An initial exposure of beef thyroid slices to 25 mU/mL thyroid-stimulating hormone (TSH) for two hours induces a diminished stimulation of cyclic adenosine monophosphate (AMP) production upon subsequent readdition of TSH but does not modify the effect of prostaglandin E1 (PGE1). Incubation of thyroid slices in calcium-free buffer with or without 2 mmol/L ethylene glycol bis (beta-aminoethyl ether)--N,N' = tetracetic acid (EGTA) prevented desensitization induced by TSH and PGE1, to the subsequent stimulation by TSH and PGE1, respectively, despite the presence of calcium in subsequent incubations. TSH-induced desensitization was not modified by increasing the calcium concentration up to 50 mmol/L in the initial incubation. However, the stimulatory effect of TSH upon cyclic AMP levels was decreased as the calcium concentration in the first incubation was increased. In the presence of at least 1 mmol/L calcium, an initial incubation of thyroid slices with 20 mumol/L ionophore A-23187 decreased the stimulation of cyclic AMP by 25 mU/mL TSH added to the slices for the first time during a subsequent incubation. Under these conditions, A-23187 had no effect on PGE1 stimulation of cyclic AMP. These results indicate that calcium may play a role in the TSH-induced, but not PGE1, desensitization of cyclic AMP formation.

Alprostadil↗
PubMed1985

Direct ovarian effect of clomiphene citrate in the rabbit.

The effects of clomiphene citrate (CC) on ovulation and ovum maturation were studied using the isolated perfused rabbit ovary. CC (10(-5) M) added to the perfusate with human chorionic gonadotropin (50 IU) did not affect ovulatory efficiency, ovulation time, oocyte maturation, or degeneration of ovulated ova and follicular oocytes. During perfusion without human chorionic gonadotropin, the percentage of follicular oocytes with germinal vesicle breakdown was significantly increased in response to CC (10(-5) M or 10(-7) M); a greater percentage of follicular oocytes was degenerated. Estradiol (100 ng/ml) added to the perfusate reversed the effect of CC on degeneration of follicular oocytes. Of follicular oocytes from ovaries perfused with CC, 79.3% were degenerated; in contrast, 25% were degenerated in ovaries treated with CC plus estradiol. These data suggest that CC has a direct ovarian effect and that ovum degeneration associated with CC may be related to an antiestrogenic action.

Animals↗
PubMed1985

Occurrence of AIDS in hemophiliacs in Japan.

This report describes the first two Japanese cases of AIDS developed in patients with hemophilia. One was a 48-year-old man with hemophilia B and the other was a 62-year-old patient with hemophilia A. They had nonspecific prodromal syndromes of AIDS initially, and later developed fatal opportunistic infections with Candida or atypical mycobacteriosis and Aspergillosis. They had marked cellular immunodeficiency, and antibodies to HTLV-III. Subsequently, three more cases of AIDS in hemophiliacs have been reported in Japan. Because most of the clotting factor concentrates for treatment of hemophilia are imported from the United States and European countries, hemophiliac patients in Japan are also at high risk for AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Effects of low-power diode lasers on flap survival.

We investigated the effect of low-power laser irradiation on the survival of experimental skin flaps in rats. A gallium-aluminum-arsenide diode laser that was developed by the Japan Medical Laser Laboratory was used. The laser power was 15 mW and the wavelength 830 nm. Irradiation was carried out, either before or after flap elevation, in two groups of 20 Wistar strain rats. A third group of 20 rats served as controls. A caudally based skin flap, 3 X 9 cm, was designed on the back of each rat. Laser irradiation therapy was performed for 5 consecutive days for 6 minutes per flap per day, preoperatively in one group and postoperatively in the other. Seven days postoperatively, the survival areas of the flaps were measured and compared. The survival area was increased significantly in both groups receiving laser therapy, probably due to the observed proliferation of blood vessels around the irradiated points and an increase in blood flow.

Animals↗
PubMed1985

Distally based abductor digiti minimi muscle flap.

The abductor digiti minimi muscle flap is known as good tissue coverage for the lateral ankle and heel. For reconstruction of the distal portion of the foot, the distally based flap of this muscle can be useful, effectively utilizing the blood supply through the plantar arch communication. A case of frostbite of the right fifth toe is reported, which we successfully repaired with a distally based abductor digiti minimi muscle flap. In addition, some information on distally based use of the muscles of the foot is presented.

Adult↗
PubMed1985

Clinical and endocrine studies on patients with amenorrhoea associated with weight loss.

Two hundred and forty-three patients with amenorrhoea associated with weight loss were studied. At the onset of amenorrhoea, regardless of percentage weight loss, basal levels of LH were low and LH responses to LHRH were impaired. However, both basal and stimulated levels of FSH were comparable to normal. With resumption of menstruation, the basal and stimulated levels of LH were found to rise to normal, while FSH responses continued to exceed normal. However, 16.6% of 66 unimproved cases had normal responses but remained amenorrhoeic. Furthermore, amenorrhoea persisted in 71% of 31 patients with complete recovery of body weight. No significant correlation was noted between percentage weight loss and responsiveness to LHRH, nor between recovery of body weight and resumption of menstruation. Return to normal weight is desirable for resumption of normal cyclic menstruation and hypothalamic-pituitary function, but is not always effective.

Adolescent↗
PubMed1985

Determination of carbamylated plasma protein and its clinical application to renal failure.

We determined carbamylated plasma protein (CPP) according to the method of Hunninghake in patients with renal failure and normal subjects. CPP values were significantly higher in patients with renal failure than in normal subjects. In patients with renal failure, a significant correlation was found between CPP levels and blood urea nitrogen. Thus, CPP appears to be a new indicator of the status of renal failure, irrespective of hemodialysis.

Blood Urea Nitrogen↗
PubMed1985

Manganese ion as a goitrogen in the female mouse.

Effect of excessive ingestion of manganese (Mn) on the mouse thyroid was assessed under the conditions of normal intake of iodide. Female mouse thyroids were enlarged after 7 weeks of administration of 200 mg/l MnCl2 X 4H2O in drinking water; 2.74 +/- 0.25 mg for control (N = 56), and 3.31 +/- 0.28 mg for Mn-treated group (N = 85) (p less than 0.001). In contrast, male mouse thyroids never became goitrous following this treatment. Manganese was goitrogenic to the castrated male mouse, but it had no effect on the testosterone-treated castrated male mouse, indicating the involvement of androgen in goiter formation. Oral administration of Mn did not severely affect blocked T/S of 125I or iodine metabolism in the thyroid. A morphological study, however, revealed that the epithelial cell in the Mn-treated mouse thyroid became flatter than that of the control. The lumens were filed with colloid in Mn-treated female mouse thyroid. The serum levels of thyroxine (T4), but not triiodothyronine (T3), were slightly reduced by Mn. These informations suggest that Mn can be a mild goitrogen for the female mouse and that the etiology of goiter formation can be interpreted by retention of colloid in the lumen.

Animals↗