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Biomedical subjects

K Shimamoto

Publications and source records attributed to K Shimamoto.

At least 415 records · Page 23Linked to original sources
PubMed1979

A direct radioimmunoassay of rat urinary kallikrein and comparison with other measures of urinary kallikrein activity.

A highly sensitive radioimmunoassay for rat urinary kallikrein (minimal detectable amount, 40 pg/tube) has been developed. The assay uses a sheep antibody (Keq = 3.25 X 10(10)M-1) against purified Sprague-Dawley rat urinary kallikrein in a final dilution of 1 : 1,200,000. The assay incorporates a convenient and inexpensive PEG technique for separation of free from bound antigen. Parallel standard curves with rat urine or kidney homogenates were obtained. No cross-reactivity with human or dog urine samples or purified human urinary kallikrein was seen. Correlations among this assay, an esterolytic method, and a kininogenase radioimmunoassay for kallikrein were highly significant, with only the esterolytic assay demonstrating any significant nonspecificity. The radioimmunoassay can detect changes in urinary kallikrein levels produced by a maneuver known to alter urinary kallikrein excretion.

Animals↗
PubMed1979

Anti-androgen TSAA-291. I. Anti-androgenic effects of a new steroid TSAA-291 (16 beta-ethyl-17 beta-hydroxy-4-oestren-3-one) and its derivatives.

Anti-androgenic properties of newly synthesized steroidal compounds, TSAA-291 and its derivatives, were studied in the rat. (1) Subcutaneous administrations of TSAA-291 and TSAA-272 were effective in depressing the weight of seminal vesicles and ventral and dorsal prostates in the adult rat. (2) TSAA-291, TSAA-328 and TSAA-272 were shown to be anti-androgenic by the subcutaneous or oral route in the immature castrated male rat treated with testosterone propionate. The dose-response curves of all the test agents expressed in terms of percentage inhibition were approximately parallel to each other. Cyproterone acetate depressed the weight of levator ani muscle dose-dependently, whereas TSAA-291, TSAA-328 and TSAA-330 did not inhibit the muscle weight in a dose range sufficiently effective in inhibiting the weight of seminal vesicles and ventral and dorsal prostates. (3) TSAA-291 was also anti-androgenic against androstenedione and dehydroepiandrosterone. (4) Local administration of the anti-androgenic compounds into the left seminal vesicle or left testis of the young adult rat depressed the weight of the seminal vesicle or testis on the treated side as compared with the vehicle-injected contra-lateral side.

Androgen Antagonists↗
PubMed1978

A sensitive radioimmunoassay method for urinary kinins in man.

A sensitive and specific radioimmunoassay method for urinary kinins was developed, which uses antiserum against synthetic bradykinin in combination with labeled tyr8-bradykinin. The assay detects as little as 6 pg per tube of bradykinin. The dose-response curves of bradykinin. lysyl-bradykinin (kallidin), and methionyl-lysyl-bradykinin were almost identical. This suggests that the values estimated with bradykinin as the standard exhibit the total urinary kinins which contain these three peptides. The assay was performed without extraction of urinary samples, since a chromatographic study demonstrated that no interfering substances in urine samples remain in our assay system. The urinary levels of total kinins in 10 normal male subjects, three male patients with chronic renal failure, and 12 male patients with essential hypertension was 37.9 +/- 3.9 microgram/day (mean +/- S.E.M.), 9.0 +/- 5.1 microgram/day, and 24.2 +/- 5.2 microgram/day, respectively.

Adult↗
PubMed1977

Enhancement of tumor induction in rats with Moloney murine sarcoma virus by a "new" method based on direct injection into fetuses.

Undiluted, fivefold-diluted, and 25-fold-diluted doses of a stock of Moloney murine sarcoma virus were injected directly, in a volume of 0.025 ml, into the backs of fetal Sprague-Dawley rats by laparotomy through the uterine wall at 18 days of gestation. During the first 8 weeks after birth the young responded to the virus with remarkably high but dose-dependent incidences of neoplasms. When a one-fifth dilution of the virus preparation was inoculated at fetal ages 16, 18, and 20 days, the incidences of lesions decreased with advancing fetal age. The tumors developed preferentially at the virus inoculation site and/or in the proximal parts of the extremeties; all were considered to be of mesenchymal derivation, i.e., malignant mesenchymoma, rhabdomyosarcoma, osteosarcoma, fibrosarcoma or fibromyxosarcoma, hemangiosarcoma, plasmacytoma, and a giant cell tumor. This injection procedure provided us with a valuable experimental tool for the rapid screening or testing of potential chemical carcinogens and other biologic studies.

Animals↗
PubMed1977

Heterogeneity of prolactin and TSH response to TRH in hypotonadotropic hypogonadism.

To evaluate prolactin and TSH secretion in isolated gonadotropin deficiency, thyrotropin-releasing hormone (TRH), in a dose of 500 microgram, was administered iv to fifteen male subjects with this disorder. In 4 out of 8 untreated patients, TRH-mediated prolactin release was significantly blunted and this attenuated response was not improved in one patient after treatment with testosterone for 1 year. In 7 patients who were treated with testosterone for 2 to 8 years, four failed to show a normal prolactin response after TRH injection. TRH-induced TSH secretion, on the other hand, was attenuated in two out of 8 untreated and in two of 8 treated patients with hypogonadotropic hypogonadism. The decreased TSH reserve was not necessarily associated with the poor prolactin response to TRH. It was concluded that heterogeneity exists in TRH-mediated prolactin and TSH release in "isolated" gonadotropin deficiency syndrome.

Adolescent↗
PubMed1977

A study of plasma vasopressin in patients undergoing chronic hemodialysis.

Plasma vasopressin (VP) was determined in 28 patients with chronic renal failure undergoing hemodialysis. Plasma VP levels were significantly higher in the patients than in the normal subjects. It was also observed that plasma VP levels did not fall significantly despite a marked decrease of effective plasma osmolality following hemodialysis, and that no correlation was obtained between the plasma VP levels and effective plasma osmolality, both before and after hemodialysis. By analyzing the changes in blood volume and blood pressure in addition to plasma osmolality in each case, a dysfunction of VP release in response to osmotic stimulus was found in 5 out of 28 patients.

Adolescent↗
PubMed1977

Permeability of antidiuretic hormone and other hormones through the dialysis membrane in patients undergoing chronic hemodialysis.

In eight patients undergoing chronic hemodialysis, ultrafiltration was performed for 1 h in each patient. The concentration of urea nitrogen, creatinine, ADH, cortisol, GH, prolactin and TSH was measured in plasma and the filtering solution, and the permeability of each substance was determined. The plasma concentration of ADH coincided with that of the filtering solution, and no significant difference was noted between the permeability of creating and ADH. In contrast, cortisol, GH, prolactin and TSH were not detected in the filtering solution. Chromatographic study showed that ADH in the filtering solution coincided with synthetic ADH. From a comparison of the permeability with the molecular weight, it was suggested that ADH in the blood exists in free form without binding with plasma proteins or neurophysin.

Adult↗
PubMed1976

Effect of norepinephrine infusion on plasma vasopressin levels in normal human subjects.

Norepinephrine was continuously infused for 30 minutes at a rate of 0.2 and 0.3 mug/kg/min into 3 normal human subjects, and plasma vasopressin levels, plasma osmolality, hematocrit value, blood pressure, and heart rate were determined simultaneously. In norepinephrine infusion, an elevation of mean blood pressure and a decrease in heart rate was seen, and the degree of these changes was greater with the infusion at a rate of 0.3 mug/kg/min. Plasma vasopressin levels were suppressed by the infusion, and a dose-response relationship was recognized between the infusion at rates of 0.2 mug/kg/min and 0.3 mug/kg/min, while plasma osmolality did not change, and the hematocrit value rose slightly. These results suggest that norepinephrine-induced water diuresis is related to the suppression of the vasopressin release.

Adult↗
PubMed1976

Effect of age and sex on circulating and pituitary prolactin levels in human.

In an attempt to determine whether age or sex affects prolactin secretion in the human, basal levels of serum prolactin, and its response to TRH administration as well as the pituitary content of this hormone were compared between both sexes and among the different agent groups. In 315 adult subjects of various ages, the mean basal levels of prolactin were found to be higher in women than in men of the same age groups with the exception of the sixth decade. The effect of age on serum prolactin concentrations, on the other hand, was not demonstrated. Similarly, the prolactin response to intravenous injections of 500 mug of TRH was significantly greater in female subjects than in males of both young and aged groups. No relationship between the prolactin response and the day of menstrual cycle in young women was apparent. Although quantitative difference in TRH-induced prolactin release was not observed between young and elderly subjects, the occurrence of prolactin peak and the elimination of the circulating prolactin following TRH administration were delayed in the aged groups. Taken together with the demonstration of a higher content of this hormone in female pituitary glands compared with those of males, it was concluded that prolactin secretion is enhanced in female subjects throughout life after puberty and that aging, per se, is not associated with an alteration in the rate of secretion of this hormone in human subjects.

Adolescent↗