Search PubMed⌕ Search

Biomedical subjects

I Abe

Publications and source records attributed to I Abe.

At least 199 records · Page 11Linked to original sources
PubMed1986

[Lipids and apolipoproteins in relation to the degree of coronary sclerosis].

86 male patients with 0-, 1-, 2- or 3 vascular disease who underwent coronary angiography as well as a control group were examined with regard to their lipoprotein constellation: total (TC-), LDL-, HDL-, beta- and alpha-cholesterol (C); triglycerides; apolipoproteins A, AI and B. Significant differences between the mean values of the control group and the patients with coronary disease were found for the groups with 2- and 3-vascular disease for the following parameters: TC, HDLC, TC/HDLC, LDLC/HDLC, alpha-C, TC/alpha-C, beta-C, alpha-C. The quotients TC/HDLC and TC/alpha-C most closely correlate with the degree of the coronary sclerosis. In the apolipoproteins A, B and the index Apo B/A the patients with coronary disease of the groups 0-3 possess equally lowered or increased serum levels and number values, respectively, in comparison to the control group. The apolipoproteins do not show any relationship to the degree of severity of the coronary sclerosis. By means of the parameters combination (Apo A + TC/alpha-C) with a diagnostic sensitiveness of 0.83 and a specificity of 0.87 a coordination coronary disease--healthy could be performed. The classification according to risks should then be performed by means of a cholesterol quotient (TC/alpha-C or TC/HDLC).

Apolipoproteins↗
PubMed1986

Is single oral administration of captopril beneficial in screening for primary aldosteronism?

Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured in 19 cases with primary aldosteronism (PA) and in 72 with essential hypertension (EHT) to differentiate the two disorders during the following conditions on normal salt diet: after overnight recumbency (basal state) and 2 hours after oral administration of 25 mg of captopril. Screening criteria were determined so that all PA patients were diagnosed as positive, and their specificities were compared with those of other conventional screening methods for PA. After captopril administration, the specificity of a criterion based on a combination of PAC and PAC/PRA ratio was 93% and positive predictive value was 79%. This criterion was superior to blood pressure response to angiotension II analog infusion, PRA on salt depletion, and to PAC on salt loading. However, higher specificity (97%) and positive predictive value (90%) were obtained from a criterion based on a combination of basal PAC and PAC/PRA ratio. Therefore, the use of a combination criterion based on PAC and PAC/PRA ratio at basal state rather than after captopril administration may give a satisfactory result in the screening for PA.

Adult↗
PubMed1986

Increased tumor tissue pressure in association with the growth of rat tumors.

In order to elucidate further the mechanisms of central necrosis formation and drug delivery into tumor tissue, the interstitial fluid pressure in the normal subcutis and in rat ascites hepatoma AH109A and AH272 tumors was measured by means of a modified diffusion chamber technique. Using our apparatus for determining tissue pressures, we can obtain an exact zero reference-point and thus analyze daily changes in tumor interstitial fluid pressure. Tumor interstitial fluid pressure was found to be always positive and significantly higher than that in the normal subcutis, which was negative (P less than 0.001). The pressure increased with tumor growth. Highly significant correlations between the tumor size and the tumor interstitial fluid pressure were observed in both AH109A (r = 0.87; P less than 0.001) and AH272 (r = 0.86; P less than 0.001). The rate of increase in this pressure differed between AH109A and AH272 (P less than 0.001). It is concluded that the elevated interstitial fluid pressure in tumors could induce central necrosis and attenuate drug delivery to tumor tissue.

Animals↗
PubMed1985

Some aspects of size-dependent differential drug response in primary and metastatic tumors.

The response of cancer to various anticancer drugs is tumor-size dependent in many aspects. In general, problems stem partly from the fact that the entire tumor cell populations do not respond equally to a certain treatment. As a result of recent progress in cancer biology, it has become evident that cellular heterogeneity of the tumor underlies the difficulties of treating primary and metastatic tumors with chemotherapy. Moreover, as tumors grow, marked diversity develops on the tissue level as well. An uneven distribution with an increase of areas of lower growth fraction and of poorer drug delivery is more distinct in larger tumors. Heterogeneous distribution and low levels of tumor blood flow are considered to be causally related to the heterogeneous nature of tumor tissue. Considering the lack of evidence of a lymphatic system within the tumor, increased interstitial fluid pressure may be a natural result that further impedes blood flow in the tumor. The fact that the temporary and selective increase in tumor tissue blood flow by angiotensin-induced hypertension produces a remarkable chemotherapeutic effect should vividly indicate that delivery of the drug to the tumor is really the 'bottleneck' of cancer chemotherapy. Tumor-size-related change in the transvascular and extravascular transport of molecules and its relevance to chemotherapy are also discussed in this article.

Antineoplastic Agents↗
PubMed1985

Increase in tumor vascular area due to increased blood flow by angiotensin II in rats.

For further elucidation of the microhemodynamics in tumor tissue, the "vascular level," percentage of the vascular area to tissue area, was measured in DONRYU rats. Changes in the vascular level due to angiotensin II were analyzed by a point-counting method in normal and tumor tissues within a rat transparent chamber. The vascular level in normal subcutis changed from 21.8 to 18.6% when the mean arterial pressure was elevated from 102.3 to 155.9 mmHg. The coefficient of change due to angiotensin II was 0.85. The vascular level in tumor tissue was distributed inhomogeneously from 0 to 48.5% with an average of 19.7%. It increased to 33.9% (range: 8.7-57.6%) with an elevation of the mean arterial blood pressure from 103.5 to 150.8 mmHg. The coefficient of change due to angiotensin II was 2.08 in tumor tissue. Moreover, the tumor vascular level increased at a higher rate in the areas with a lower vascular level.

Angiotensin II↗
PubMed1985

[Functional characterization of microcirculation in tumors: chemotherapeutic implications].

This report describes some aspects of tumor vessels and the functional characteristics of tumor microcirculation with regard to selective increase in tumor blood flow. Elevation of the mean arterial blood pressure to about 150mmHg by angiotensin II resulted in a several-fold increase in blood flow in tumor tissues without increasing blood flow in normal tissues. Pressure elevation by angio-tensin II also selectively increased tumor blood flow in intra-corneally transplanted microfoci and influx of lymph flow from the primary lesion to lymph node metastatic lesions. New techniques for analyzing microhemodynamics of tumor vessels showed that the vascular level in tumor tissues and the hydrostatic pressure difference between the tumor vessels and extravascular tissue were enhanced. Thus a new approach to cancer chemotherapy (ATII-induced hypertension chemotherapy) has been demonstrated in which the delivery to tumor tissue of systemically administered anticancer drugs can be selectively enhanced.

Angiotensin II↗
PubMed1985

[Enhancement of vascular level in tumors under angiotensin-induced hypertension].

The change in tumor vascular area seems to be one of the important factors influencing drug delivery to tumor tissue. By means of a point-counting method we analyzed changes in the "vascular level", percentage of the vascular area to tissue area, in two tumors; AH272, AH109A, comparatively under angiotensin-induced hypertension. In tumor AH272, the vascular level changed from 27.4% (range; 19.7-34.9%) to 38.5% (range; 28.2-48.1%) when mean arterial blood pressure elevated from 98.3 to 151.7 mmHg. The change coefficient due to angiotensin II was 1.42. The vascular level in AH109A tumor tissue increased from 19.7% (range; 0-48.5%) to 33.9% (range; 8.7-57.6%) with an elevation of mean arterial pressure from 103.5 to 150.8 mmHg. The change coefficient was AH109A in 2.08. In-homogeneity in the vascular level in tumor tissue was more marked in AH109A than in AH272. Moreover, it was revealed in AH 109A that the increase in the vascular level due to angiotensin II was greater in the areas with a lower vascular level. This seems to be caused by the phenomenon that blood flow appearing under angiotensin-induced hypertension in tumor vessels that lacked blood flow at normotension. In conclusion, selective increase in vascular level was seen in both tumors under angiotensin-induced hypertension.

Angiotensin II↗
PubMed1985

[Changes in tumor transvascular pressure difference associated with tumor growth: implications for angiotensin-induced hypertension chemotherapy].

In order to further elucidate the mechanism of drug delivery to tumor tissue, changes in tumor vessel pressure and interstitial fluid pressure associated with tumor growth were measured by means of a compression method and a micro-occlusion method and a diffusion chamber method, respectively. Tumor interstitial fluid pressure was always positive and much higher than that in the normal subcutis. Furthermore the pressure became higher as the tumor mass grew. Conversely, tumor vessel pressure was reduced with tumor growth. Increase in the interstitial fluid pressure and slight decrease in the tumor vessel pressure should together result in a reduction of the hydrostatic pressure difference between the intravascular and extravascular space of the tumor, which seems to be one of the important factors influencing fluid exchange and drug delivery. However, the transvascular pressure gradient in the tumor was increased under angiotensin-induced hypertension, resulting in advantageous conditions for drug delivery.

Angiotensin II↗
PubMed1984

Functional characterization of the microcirculation in tumors.

This review describes some aspects of tumor vessels and the influence of vasoactive agents on tumor blood flow, particularly the characteristic microcirculation of tumors with regard to its selective increase in blood flow. Elevation of blood pressure by infusion of angiotensin II produced a severalfold increase in tumor blood flow. The increase was selective and specific to the tumor vessels as long as the mean arterial blood pressure was kept under 150 mm Hg. Pressure elevation by angiotensin II also selectively increased tumor oxygen tension and influx of lymph flow from the primary transplanted lesion to the lymph node metastatic lesion. Newly devised techniques for analyzing microhemodynamics of tumor vessels showed that the velocity of tumor blood flow, the vascular area in tumor tissue, and the hydrostatic pressure difference between the tumor vessel and extravascular tissue were markedly enhanced. Thus, the extravasation of material into tumor tissues can be increased by the enhancement of blood flow. This demonstration allowed the development of a new approach to cancer chemotherapy, in which the delivery to tumor tissue of systemically administered anticancer drugs can be selectively enhanced.

Angiotensin II↗
PubMed1984

Sodium erythorbate is not carcinogenic in F344 rats.

Carcinogenicity of sodium erythorbate, a widely used antioxidant food additive, was evaluated using a total of 306 eight-week-old male and female F344/DuCrj rats. Test rats were given 1.25 or 2.5% aqueous solution as drinking water for 104 weeks. Controls were given tap water. All the rats were fed commercial pellets. None of the tumors observed was attributable to sodium erythorbate in drinking water. Neither concentration of sodium erythorbate changed the pattern of spontaneous tumor development in both sexes, except for a slight reduction in aggregate tumor incidence in the 2.5% Group females. Additionally, 2.5% solution suppressed body weight gains in both males and females. These results and prior data by others together suggest that weak mutagens may be noncarcinogenic under certain conditions.

Aging↗
PubMed1984

The renin-angiotensin-aldosterone system and circadian rhythm of urine variables in normotensive and hypertensive subjects.

Forty-two middle-age male subjects, aged from 47 to 54 years old, were divided into three groups; 14 normotensives (NT), 16 borderline hypertensives (BHT) and 12 hypertensives (HT). The environmental effects were neutralized as much as possible by keeping their activities synchronized and their plasma and urine variables simultaneously investigated using the same protocol as under normal physiologic conditions. The circadian rhythms of urinary excretions of Na, K, Cl, creatinine, aldosterone, adrenaline and noradrenaline were analyzed by a multivariate method (cosinor method). Both systolic and diastolic blood pressure were statistically significantly different among the three groups and body weight was greater in HT than in NT. Other plasma and urine variables examined, however, were not significantly different among the three groups. A statistically significant circadian rhythm was detected in the urine variables. The rhythm characteristics, such as the mesor, amplitude and acrophase, of the urine variables except for the acrophase of urinary Na excretion were not significantly different among the three groups; the circadian acrophase of urinary Na in HT and BHT appeared significantly earlier than in NT. The pathophysiological and clinical significance of the earlier appearance of the circadian acrophase of urinary Na in hypertensive subjects still remains a unique characteristic requiring further investigation.

Aldosterone↗
PubMed1984

Prognostic evaluation of early detection of relapse in adult acute leukemia.

A criterion was established in a previous study to detect the relapse of adult acute leukemia in its early stage, i.e., when lymphocytes in peripheral blood increased over 45% of the leukocytes during the maintenance therapy, bone marrow puncture was immediately performed to examine the leukemic cells. By this criterion the relapse was detected earlier than by other criteria. To study the effect of early detection of the relapse in adult acute leukemia on the results, the second remission rate and the survival time were compared between the following groups. Group I consisted of 11 patients, whose relapse was determined by our criterion. Group II consisted of 8 patients whose relapse was determined by the appearance of leukemic cells in peripheral blood. The second remission was accomplished in 7 of 11 patients in Group I (64%) and in 1 of 8 in Group II (13%) (p less than 0.05). The mean (+/- S.D.) duration of complete remission in Group I was 9.7 +/- 7.8 months and not significantly longer than the value in Group II (5.3 +/- 3.9 months). The interval from relapse to death was 10.3 +/- 5.9 and 6.1 +/- 3.8 months in Groups I and II, respectively. The interval from relapse to death of 7 patients who accomplished the second remission in Group I was 12.5 +/- 5.5 months. This interval was significantly longer than in Group II (p less than 0.02). The mean survival time was 22.2 +/- 9.6 months in Group I and 13 +/- 2.5 months in Group II. The mean survival time of 7 patients accomplished the second remission in Group I was 26. 7 +/- 9.4 months which was significantly longer than in Group II (p less than 0.01). The results showed that our criterion to detect relapse in the early stage was effective for prolongation of the survival time in adult acute leukemia.

Acute Disease↗
PubMed1984

Catecholamines, angiotensin II and sodium concentrations in cerebrospinal fluid in young men with borderline hypertension.

To evaluate the role of central nervous mechanisms and their relationships to the peripheral sympathetic nervous system in borderline hypertension, we measured catecholamines, angiotensin II (AII) and sodium (Na) concentrations in cerebrospinal fluid (CSF) with plasma catecholamines concomitantly in 12 young men with borderline hypertension and 7 age-matched healthy normotensive men on ordinary salt intake. Plasma norepinephrine (NE) and epinephrine (E) were higher in the borderline hypertensives than in the normotensives (NE: 239 +/- 15 vs 190 +/- 11 pg/ml, p less than 0.05, E: 83 +/- 9 vs 43 +/- 6 pg/ml, p less than 0.01). NE levels in CSF were also higher in the borderline hypertensives than in the normotensives (200 +/- 15 vs 150 +/- 18 pg/ml, p less than 0.05). In most of the subjects, CSF E and plasma and CSF dopamine levels were below the sensitivity of the assay. CSF NE correlated positively with both plasma NE (p less than 0.01) and mean blood pressure (p less than 0.05) in all subjects. Immunoreactive AII and Na concentrations in CSF did not differ between the borderline hypertensives and normotensives. These results suggest that peripheral sympathoadrenal overactivity in young subjects with borderline hypertension may be related to an altered function of central noradrenergic neurons. AII and Na in the central nervous system do not appear to have an important role in borderline hypertension.

Adolescent↗
PubMed1983

Acute electrocardiographic effects of captopril in the initial treatment of malignant or severe hypertension.

We evaluated electrocardiographically the acute effect of captopril in the initial treatment of malignant or severe hypertension and the findings were compared with the data obtained with diazoxide. The captopril group included seven patients treated with captopril or with a combination of diuretics. The diazoxide group included seven patients initially treated with diazoxide. A significant and similar degree of reduction in blood pressure was observed the second day after treatment in both groups. From 15 to 60 minutes after treatment, however, the reduction in mean blood pressure was more pronounced in the diazoxide group and was followed by a reflex tachycardia. In the diazoxide group, two patients went into shock and another three had nausea and vomiting, whereas in the captopril group there were no complications in any of the patients. In the captopril group ECG ST-T findings in leads V5 and V6 did not deteriorate, while in the diazoxide group there was a significant deterioration (p = 0.01). Thus captopril may be an effective and safe compound for the initial treatment of malignant or severe hypertension.

Adult↗
PubMed1983

Prediction of sensitivity to 1-beta-D-arabinofuranosylcytosine by the plateau level of its 5'-triphosphate in human lymphoblastic cell lines in vitro.

Parameters for metabolism of 1-beta-D-arabinofuranosylcytosine (ara-C) were examined to know whether the prediction of ara-C sensitivity is possible or not using 9 human lymphoblastic cell lines, 3 T cell lines and 6 B cell lines in vitro. Neither the capacity for synthesis, degradation of 1-beta-D-arabinofuranosylcytosine 5'-triphosphate (ara-CTP), generally lower in the T than B cell lines, nor deamination of ara-C, negligible in the B cell lines, could be correlated to the drug sensitivity. On the other hand, significant correlation was obtained between the sensitivity and the plateau level of ara-CTP. We consider that ara-C sensitivity could be predicted by measuring the plateau ara-CTP level before commencement of chemotherapy.

Arabinofuranosylcytosine Triphosphate↗