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Biomedical subjects

H Koike

Publications and source records attributed to H Koike.

At least 415 records · Page 23Linked to original sources

Crystallization and preliminary crystallographic analysis of the major NAD(P)H: FMN oxidoreductase of Vibrio fischeri ATCC 7744.

The major flavin reductase from Vibrio fischeri, FRase I, has been crystallized in the presence of FMN by the vapor diffusion method using polyethylene glycol 4000 as a precipitant. The crystals belonged to the monoclinic space group C2 with unit cell dimensions, a = 101.6 A, b = 63.2 A, c = 74.4 A, and beta = 100.0 degrees. The crystals are expected to contain two FRase I molecules per asymmetric unit. The crystals diffracted X-rays to at least 2.2 A resolution and are appropriate for structural analysis at high resolution.

Crystallization↗

Antihypertensive effects of captopril in combination with diuretics in spontaneously hypertensive rats.

To examine the antihypertensive effects of captopril, when used in combination with diuretics, an oral dose of the agent (30 mg/kg) was given to spontaneously hypertensive rats pretreated for 1 week with trichlormethiazide (TCTZ), hydrochlorothiazide (HCTZ), furosemide, or water. One-week treatment with diuretics did not lower blood pressure, but potentiated the anti-hypertensive action of captopril in magnitude as well as duration. The degree of potentiation was in the following order: furosemide greater than or equal to HCTZ greater than TCTZ. Plasma renin concentration (PRC) prior to the administration of captopril was highest in the furosemide group, followed by the HCTZ, TCTZ, and control groups, in this order. When data from four groups were taken together, the reduction of blood pressure following captopril administration was closely related to PRC before administration. These data suggest that repeated administration of diuretics renders the maintenance of blood pressure more dependent on the renin-angiotensin system without affecting blood pressure and that this situation underlies the potentiation of the antihypertensive action of captopril by combined use of diuretics. There was no qualitative difference between furosemide and thiazides in the potentiation of anti-hypertensive action of captopril.

Aldosterone↗

Diagnostic value of hair shafts and squamous cells in peritoneal washing cytology.

OBJECTIVE: Little attention has been given to hair shafts and squamous cells in peritoneal fluid. To investigate their diagnostic value in peritoneal washing specimens, we reviewed peritoneal washing cytology preparations from 83 cases of ovarian tumors. STUDY DESIGN: We reviewed peritoneal washing specimens and histologic sections of 86 cases of ovarian tumors and tumorous conditions, including 22 teratomas, 16 serous adenocarcinomas, 10 clear cell adenocarcinomas, 9 endometrioid adenocarcinomas, 5 cases of endometriosis, 4 mucinous adenomas, 3 serous cystadenocarcinomas and 17 other tumors. RESULTS: We observed both squamous cells and hair shafts surrounded by inflammatory cells in 5 of the 22 cases of ovarian teratoma. Rupture of an ovarian teratoma was clinically and histologically found in one of the five cases. Hair shafts were not observed in the other tumors or in nonneoplastic conditions. The diameter of hair shafts in peritoneal washing specimens ranged from 10 to 28.8 microns (average, 16.6), and such hair shafts were present within an ovarian teratoma examined histologically. The diameter of hair shafts from six normal adults who were examined as controls ranged from 61.5 to 118.6 microns (average, 89.4). CONCLUSION: Hair shafts and squamous cells surrounded by inflammatory cells in peritoneal washing specimens are a diagnostic clue to ovarian teratoma and can be observed even when rupture of the tumor is not detected clinically or microscopically.

Adolescent↗

Effects of long-term blockade of angiotensin converting enzyme with captopril (SQ14,225) on hemodynamics and circulating blood volume in SHR.

Male spontaneously hypertensive rats (SHR), 13 weeks old, received oral administration of captopril (SQ14,225) daily at a dose of 10 mg/kg or 30 mg/kg; or water at 2 ml/kg, for 6 weeks. Captopril suppressed the development of hypertension slightly at the lower dose and completely at the higher dose. At 6 weeks of dosing, hemodynamic parameters were measured by the tracer microsphere method and blood volume by the dilution method using 51Cr erythrocytes. Cardiac output (CO) increased and mean blood pressure decreased in a dose-dependent manner; thus, total peripheral resistance decreased. Cerebral and renal blood flows increased in a dose-dependent manner while blood flow to other organs tended to increase or remained unchanged. There was no significant differences in the circulating blood volume among the three groups. In conclusion, long-term blockade of angiotensin converting enzyme (ACE) with captopril dilated blood vessels in the whole body, especially in the brain and kidney, and lowered blood pressure without causing plasma expansion or tachycardia.

Angiotensin-Converting Enzyme Inhibitors↗

Highly potent and specific inhibitors of human renin.

Small peptide analogues representing the C-terminal portion of angiotensin I sequence were designed as inhibitors of human renin. Among synthesized compounds, benzyloxycarbonyl (-"Z")-(1-naphthyl)Ala-His-leucinal (ES-188), Z-(1-naphthyl)Ala-His-statine ethyl ester (ES-226), and Z-(1-naphthyl)Ala-His-statine 2-methylbutylamide (ES-254) markedly inhibited human and primate renins (inhibitory concentration, 50% [IC50], near 10(-7) M). These peptide analogues inhibited rabbit renin with one or two orders of magnitude less potency. They were very weak inhibitors of renins from pig, goat, dog, and rat. ES-188 had no discernible effect on cathepsin D, pepsin, or human angiotensin-converting enzyme at the concentration of 10(-4)M. ES-226 had little effect on the three enzymes at the concentration of 10(-5)M; however, ES-254 had a considerable inhibitory effect on cathepsin D (IC50 of 1.4 X 10(-5)M), pepsin (IC50 of 4.2 X 10(-5)M), and human angiotensin-converting enzyme (IC50 of 7.1 X 10(-6)M). Our results indicate that 1-naphthylalanine-containing tripeptide analogues are highly potent human renin inhibitors.

Angiotensin I↗