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Biomedical subjects

I Abe

Publications and source records attributed to I Abe.

At least 217 records · Page 12Linked to original sources
PubMed1983

Activation of renin-angiotensin system in maintenance of high blood pressure in uncomplicated pheochromocytoma--a case report.

In a patient with an uncomplicated pheochromocytoma, we observed high basal value of plasma renin activity (PRA), 16.2 ng/ml/h, and a remarkable elevation in PRA from 18.2 to 90.4 ng/ml/h and concomitant blood pressure reduction following a single oral administration of 25 mg of captopril. The response was same as that observed in renovascular hypertensives, and disappeared during the period of alpha-, beta-blocker administration or after the surgery. Basal PRA also returned to low normal level. The renin-angiotensin (R-A) system probably had a role in the maintenance of high blood pressure. The mechanism of the activation of the R-A system was thought to be renal vasoconstriction due to excessive circulating catecholamines.

Adrenal Gland Neoplasms↗
PubMed1983

A micro-occlusion technique for measurement of the microvascular pressure in tumor and subcutis.

A new technique for indirect measurement of microvascular pressure in normal and tumor tissue was developed, by using a microneedle which occludes the microvessels without disturbing the microcirculation system. Thus, the microvascular pressure either in normal subcutis or in tumor tissue can be measured precisely at the single vessel level. There was a considerable drop of the pressure in the smaller arterioles (less than 40 microns in diameter) in proportion to their diameters, while the pressure profile in venules was almost flat irrespective of their diameters. The mean pressure of venules 10-50 microns in diameter was 12.0 +/- 5.2 cm H2O, and some preliminary data obtained in pressure measurement of tumor vessels are also presented.

Animals↗
PubMed1983

[Increase in tumor microvascular pressure by angiotensin-induced hypertension: implication for pharmacokinetic analysis of drug delivery into tumor tissue].

Tumor microvascular pressure was measured by using a newly developed transparent chamber of rat. The pressure of tumor vessels, 20-100 microns in diameter, increased from 9.2 +/- 2.6 cm H2O to 15.4 +/- 3.2 cm H2O when the mean arterial pressure was elevated from 103.3 +/- 8.6 mmHg to 159.2 +/- 7.9 mmHg with continuous infusion of angiotensin II. It was frequently observed that the blood began to flow into the vessels in tumor tissue, where the statis of flow had been seen, when the pressure was elevated from normotension to hypertension by angiotensin II. Based on the results obtained, the mechanism of drug delivery into tumor tissue was discussed in correlation with the enhancement of chemotherapeutic effects in both animal experiments and cancer patients by induced hypertension chemotherapy.

Angiotensin II↗
PubMed1982

Elevated plasma catecholamines without alteration in cardiovascular responsiveness in young men with borderline hypertension.

Plasma catecholamines and cardiovascular responses to upright posture, exogenous noradrenaline (NA), and isoproterenol (IP) were examined in 20 young men with borderline hypertension and in 10 age-matched normotensive volunteers. Resting plasma NA and adrenaline (Ad) levels were higher in the borderline hypertensive patients. Significant correlations were found among plasma NA and mean blood pressure (MBP) or heart rate (HR), and between plasma Ad and HR in all individuals in the supine position. The increases in plasma NA were similar between groups for orthostatic positions. Pressor response to exogenous NA and chronotropic response to exogenous IP were not augmented in borderline hypertensives. A negative correlation was found between plasma NA before infusion and the increases of MBP produced by NA or the increases of HR produced by IP in all the individuals. Our observations suggest that there is hyperactivity of the sympathoadrenal system without enhancement in cardiovascular reactivity to catecholamines in young men with borderline hypertension.

Adult↗
PubMed1982

Augmented sympathetic nervous function in young subjects with borderline hypertension.

In order to elucidate the mechanism of blood pressure elevation in the patients with borderline hypertension, the sympathetic nervous activity was investigated and the following results were obtained: 1) Plasma catecholamine (CA) levels were elevated in young men but not in middle-aged men with borderline hypertension in comparison with age-matched normal men. 2) Cardiovascular responsiveness to exogenous CA was not augmented in young men with borderline hypertension. 3) Cerebrospinal fluid noradrenaline levels were elevated in young men with borderline hypertension. They correlated positively with plasma NA or blood pressure. 4) In young men with borderline hypertension, plasma and urinary CAs were not altered by hypertonic saline loading. These results suggest that increased activity of the central and peripheral sympathetic nervous system is an important mechanism of blood pressure elevation in young subjects with borderline hypertension.

Adult↗
PubMed1982

Role of dephosphorylation in accumulation of 1-beta-D-arabinofuranosylcytosine 5'-triphosphate in human lymphoblastic cell lines with reference to their drug sensitivity.

After a 3-day exposure to 0.1 microM 1-beta-D-arabinofuranosylcytosine (ara-C) in culture, growth was inhibited to 5.6% in MOLT-4F, 25% in Raji, and 91% in Daudi cells compared with control. Growth inhibition was more profound when exposure time was extended up to 7 days. Inhibition of DNA synthesis varied with sensitivity to ara-C. Plateau levels of intracellular 1-beta-D-arabinofuranosylcytosine 5'-triphosphate (ara-CTP) were 35.5, 13.4, and 3.6 nmol/10(9) cells exposed to 0.1 microM ara-C in MOLT-4F, Raji, and Daudi cells, respectively, corresponding to the sensitivity to ara-C. The nucleotide levels at the plateau, however, did not correspond to the initial levels of the ara-CTP or to the calculated rate of ara-CTP synthesis, which decreased from Raji to MOLT-4F to Daudi cells. ara-C deamination had negligible effect on the differential accumulation of ara-CTP. ara-CTP degradation due to dephosphorylation was marked in Raji and Daudi cells but slight in MOLT-4F cells. The half-life of intracellular ara-CTP was 204, 26.4, 31.1 min in MOLT-4F, Raji, and Daudi cells, respectively. The ara-CTP level was considered to be maintained bimodally by synthesis and degradation of the nucleotide. This conclusion was supported by the fact that, in Raji and Daudi cells exposed to 0.1 microM ara-C in the presence of 1 mM hydroxyurea, the plateau levels of ara-CTP increased 3-fold through inhibition of the nucleotide degradation. Thus, not only ara-C phosphorylation but also subsequent ara-CTP dephosphorylation was important in the accumulation and maintenance of ara-CTP and in the sensitivity to ara-C.

Arabinofuranosylcytosine Triphosphate↗
PubMed1982

Carcinogenicities of 3-methoxy-4-aminoazobenzene, N-hydroxy-3-methoxy-4-aminoazobenzene and related azo dyes in the mouse.

The carcinogenicities of 2-methoxy-4-aminoazobenzene and 3-methoxy-4-aminoazobenzene (2-MeO-AAB and 3-MeO-AAB) and their N-hydroxy derivatives (N-OH-2-MeO-AAB and N-OH-3-MeO-AAB) were tested in (C3H X C57BL/6) F1 mice. Topical sc injections, twice weekly for 8 weeks, of 4 or 8 mumol of N-OH-3-MeO-AAB dissolved in 0.1 ml of olive oil containing 10% dimethyl sulfoxide induced fibrosarcomas at the site of application. Similar treatment with 3-MeO-AAB or 2-MeO-AAB as well as N-OH-2-MeO-AAB failed to induce sarcomas. Oral administration of 0.09% 3-MeO-AAB in the diet for 13 months induced hepatic tumors in female mice but not in males. 2-MeO-AAB did not induce tumors in male or female mice. The relationship between carcinogenicity, mutagenicity, the ability to induce unscheduled DNA synthesis, and the metabolism of these azo dyes is discussed.

Animals↗
PubMed1982

[Correlation between ara-C sensitivity and intracellular ara-C concentration in a cultured human lymphocyte model].

Sensitivity to cytosine arabinoside (ara-C), i.e.; the relative viable cell count on day 5 after incubation of the cell suspension (3 X 10(5) cells/ml) with 0.1 microM (2.4 ng/ml) ara-C, could be correlated with the plateau level of ara-CTP in eight out of 10 human lymphoblastic cell lines tested in vitro (correlation coefficient; r = -0.76, p less than 0.05). The plateau ara-CTP level was estimated by the incubation of the cell suspension (5 X 10(6) cells/ml) with 0.1 microM 3H-ara-C for 4 hr. The ara-CTP level was certified to be determined by the capacity for not only ara-C phosphorylation but also the ara-CTP degradation in the B-cell lines, and, in addition, by the ara-C deamination in the T-cell lines.

Cell Line↗
PubMed1982

Selective increase in tumor oxygen tension with angiotensin II.

A rise in mean arterial blood pressure to approximately 150 mm Hg by infusion of angiotensin II was accompanied by an approximate 6.4-fold selective increase in oxygen tension in tumor tissue without increasing oxygen tension in uninvolved tissues of the tumor-bearing host. The results were obtained in experiments employing subcutaneously transplanted AH109A solid tumors in Donryu rats. Changes in tissue oxygen tension were examined polarographically by means of an exposed platinum electrode.

Angiotensin II↗
PubMed1981

[Plasma cortisol concentrations and circadian rhythm in healthy young Japanese and caucasians (author's transl)].

We report herein a method of solid-phase radioimmunoassay (RIA) for assessment of plasma cortisol concentration using 125I-labeled ligand [CORTCTK-125]. Plasma cortisol concentrations and its circadian rhythm in healthy young Japanese and American whie women were also evaluated using CORTCTK-125. Nineteen Japanese women, of an average age of 20.3 +/- 0.1 years, and 12 Caucasians of mixed ethnic origin (Minnesota), average 20.0 +/- 0.5 years, were studied using a similar protocol. The distribution of the menstrual stage of the two groups was similar. Blood was drawn from each subject into EDTA containers at 4-hour intervals starting at 0800 on one day and was continued for the ensuing 24 hours. The samples were immediately placed in a refrigerated centrifuge at 4 degrees C, and then stored at -20 degrees C until the assay. The samples from Minnesota were packed in dry ice and brought by air to Japan. Determinations of plasma cortisol concentration in samples from both groups were carried out at Kyushu University. Advantages of the solid-phase RIA method are as follows: (1) 0.05 ml of plasma or serum was sufficient for determination of plasma cortisol concentrations, (2) no other solvents or solutions for the extraction or purification were required, (3) the procedure was simple and readily facilitated, and (4) the concentration of cortisol in heparin-plasma was somewhat higher than that in serum or EDTA-plasma, but there was no statistical difference. Plasma cortisol concentrations in the samples from the Japanese (19.73 +/- 1.44 on the first and 18.94 +/- 1.32 microgram/dl on the second day) and that of the American group (17.48 +/- 2.38 and 19.37 +/- 2.16 microgram/dl, respectively) at 0800 was similar. The average value of 7 determinations at 4-hour intervals was 11.01 +/- 2.00 microgram/dl in the Japanese and 10.29 +/- 1.05 microgram/dl in the American group. A remarkable and similar circadian rhythm was observed in both groups with a peak at 0800 and with nadirs at 2000 in the Japanese (4.80 +/- 0.45 microgram/dl) and 2400 in the American group (5.18 +/- 0.83 microgram/dl). There were statistically significant differences between the values at the peak and the nadir. The related subjects were then classified into Group-F (9 subjects) and Group-T (9); the former included high body mass index [BMI: body weight(kg)/body height(m)2] of more than 24.0, and the latter included a relatively lower BMI of less than 21.5. The circadian rhythm of both groups revealed a similar pattern, whereas plasma cortisol concentration was always higher in Group-F than in Group-T, at all 7 determinations. There were no significant differences except for the value at 0400. Furthermore, the average values of plasma cortisol concentration and circadian rhythm were compared; the group with a larger body surface area (BSA) (Group-L) and the group with a smaller BSA (Group-S). No difference was found in the plasma cortisol concentration of Group-L and -S, and the circadian rhythm was similar in both groups...

Adult↗
PubMed1981

Antihypertensive effect of E-643, a new alpha-adrenergic blocking agent.

To determine whether E-643, a new alpha-blocking agent, would reduce the blood pressure, regardless of the posture, a 1 mg dose was given 3 times daily for 7 consecutive days, to 8 male and 7 female inpatients, aged 37--73 years, with essential hypertension. Blood pressure and pulse rate were measured daily in the supine, sitting and standing positions. Before and after the treatment with E-643, plasma levels of noradrenaline, adrenaline, dopamine-beta-hydroxylase, renin and aldosterone were determined, samples being obtained with the subjects recumbent and after standing upright for 60 min. A significant reduction in the systolic and diastolic blood pressures was evident in the supine (172 +/- 31/100 +/- 12 leads to 151 +/- 28/89 +/- 14 mmHg), sitting (158 +/- 22/101 +/- 11 leads to 138 +/- 28/89 +/- 15 mmHg) and standing (153 +/- 32/103 +/- 21 leads to 129 +/- 31/89 +/- 20 mmHg) positions. The reduction in blood pressure remained unchanged throughout the period of administration of E-643. Pulse rate was not affected when the subjects were supine (67 +/- 10 leads to 69 +/- 10 beats/min), but was increased in the sitting (68 +/- 10 leads to 73 +/- 9 beats/min) and standing (73 +/- 10 leads to 81 +/- 11 beats/min) positions. The increased pulse rate tended to decline during continued administration of E-643. Treatment with E-643 produced no significant change in plasma levels of adrenaline, noradrenaline, dopamine-beta-hydroxylase, renin and aldosterone. The antihypertensive effect of treatment was more prominent in the patients with higher levels of plasma catecholamines and dopamine-beta-hydroxylase, and was less prominent in those with higher plasma renin and aldosterone. Two patients had temporary bouts of dizziness and visual disturbances, but there were no subjective complaints during treatment.

Adrenergic alpha-Antagonists↗