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Biomedical subjects

I Abe

Publications and source records attributed to I Abe.

At least 181 records · Page 10Linked to original sources
PubMed1990

[A case of multiple peripheral pulmonary carcinoids showing a diffuse lung disease synchronously associated with sigmoid colon cancer].

Reported is a rare case of a multiple peripheral pulmonary carcinoids showing a diffuse lung disease synchronously associated with a sigmoid colon cancer. An abnormal chest shadow was detected in a 75-year-old male by X ray during a periodic health examination. After admission to hospital for a more thorough examination he was found to have a sigmoid colon cancer. A CT scan of his chest suggested sarcoidosis, but the results of a bronchofiberscopic examination appeared normal. Subsequently, a TBLB specimen revealed typical carcinoid tumors. Thus, the diagnosis of diffuse multiple peripheral carcinoids was made. A surgical resection of the sigmoid colon cancer was performed successfully, but five months later, the patient died of acute pneumonia. An autopsy was not permitted. Also discussed are multiple pulmonary carcinoids and a double cancer.

Adenocarcinoma↗
PubMed1989

Activation of renal sympathetic outflow by intracisternal hypertonic NaCl in dogs.

The neurohormonal and sympathetic nervous system responses to injection of hypertonic NaCl (1.5 M) into the cisterna magna were investigated in morphine-pentobarbital-anesthetized dogs (n = 8). Mean arterial blood pressure (MAP), heart rate (HR), and integrated efferent renal sympathetic nerve activity (ERSNA) were recorded, and blood samples were taken for the determination of plasma concentrations of epinephrine (Epi), norepinephrine (NE), arginine vasopressin (AVP), osmolality, plasma renin activity (PRA), and serum sodium and potassium. By 2 min after injection of hypertonic NaCl into the cisterna magna, significant increases were observed for MAP (+47 +/- 5 mmHg, P less than 0.01), HR (+59 +/- 11 beats/min, P less than 0.01), and ERSNA (+47 +/- 16%, P less than 0.01) above base line. The increased activity of the sympathetic nervous system was not accompanied by changes in PRA, Epi, NE, or AVP. Hypertonic NaCl was injected into the cisterna magna of six dogs before and after intravenous administration of the AVP antagonist [d(CH2)5Tyr(Me)]AVP. The time course for increases in MAP, HR, and ERSNA was not affected by AVP blockade. Subsequent administration of hexamethonium chloride abolished the pressor, tachycardic, and ERSNA responses elicited by cisterna magna injection of hypertonic NaCl. These experiments indicate that hypertonic NaCl acts at the lower brain stem to activate the sympathetic nervous system. Further, the pressor and tachycardic responses evoked by hypertonic NaCl acting at the lower brain stem do not appear to involve the hypothalamic-hypophysial-adrenal axis.

Animals↗
PubMed1989

Evaluation of programs for the diagnosis, treatment and follow-up of hypertension in work site population.

Hypertensives screened among a work-site male population were treated either with or without antihypertensive drugs according to WHO stage of hypertension, and followed up by medical teams at the work site. The outcome during 8 years of follow-up was compared between two hypertension cohorts; one (cohort 1) instituted in 1970 included 1,092 hypertensives from 11,860 employees, while the other (cohort 2) made in 1975 contained 1,190 from 10,789 persons. Age-adjusted mortality or morbidity rate from cardiovascular diseases (CVD) was lower in cohort 2 than in cohort 1. Multiple regression analysis was used to adjust inter-cohort differences in factors to influence the prognosis, showed that CVD occurred less frequently in cohort 2 than in cohort 1. The results suggest that this system of controlling blood pressure is useful in preventing CVD in a large population.

Cardiovascular Diseases↗
PubMed1989

Functional characteristics of tumor vessels: selective increase in tumor blood flow.

This experiment was carried out to elucidate how tumor microcirculation differs from that of normal tissues. Pressure-flow relationship was examined in normal rat tissues, uninvolved tissues in tumor-bearing rats, transplanted AH109A solid tumors, and primary tumors induced by 3-methylcholanthrene. Tumor blood flow was measured by the hydrogen clearance technique. The blood pressure was elevated by continuous iv infusion of angiotensin II. Elevation of blood pressure produced a several-fold increase in tumor blood flow without increasing blood flow in normal tissue and uninvolved tissue in tumor-bearing rats. The increase was selective to tumor tissues as long as the mean arterial blood pressure remained under about 150 mmHg. The lower the resting tumor blood flow, the greater the increase in the flow was at induced hypertension. There were no significant differences in the resting blood flow and in the rate of flow change at induced hypertension between the intramuscularly transplanted tumor, the intrahepatically transplanted tumor, and the sc transplanted tumor. These results indicate that the delivery of systemically administered anticancer drugs could be selectively enhanced in tumor tissues by induced hypertension.

Animals↗
PubMed1989

[A new drug delivery system in metastatic foci of cancer].

To improve the cancer chemotherapeutic effects on metastatic foci, we have developed a new drug delivery system based on two functional characteristics of the tumor vessels. Two functional characteristics of tumor vessel are summarized as follows: 1) A several-fold increase in tumor blood flow was brought about by angiotensin II-induced hypertension. The increase was selective and universal to the tumor vessels as long as the mean arterial blood pressure was kept under 150 mmHg. Such characterization was observed in micrometastatic foci. The concentration of anticancer drugs in tumor tissue could be increased by this function. Angiotensin-induced hypertension chemotherapy has been developed based on this characterization of tumor vessels. 2) Tumor blood flow almost decreased to zero when the mean arterial blood pressure was decreased to 60-65 mmHg by infusion of sodium nitroprusside. The stasis of tumor blood flow was also selective for the tumor tissues. The stasis suppressed a drug efflux from tumor tissues. By utilizing combination of these functional characteristics, we were able to enhance drug concentration X retention time in tumors remarkably. We named this drug delivery system "Flooding-the-castle chemotherapy". In these experiments, optimum blood pressures were kept under control by a computer system.

Angiotensin II↗
PubMed1988

Solvent extraction clean-up for pre-treatment in amino acid analysis by gas chromatography. Application to age estimation from the D/L ratio of aspartic acid in human dentine.

Solvent extraction, a clean-up method for samples for the determination of amino acids by gas chromatography, was investigated and compared with a conventional ion-exchange purification. Amino acids were esterified with isopropanol and extracted with various organic solvents. The solubilities of the amino acid isopropyl esters increased with increasing solvent polarity and the size of the amino acids. The optimum pH was found to be 10.5. The method was applied to the estimation of ages by measurement of the D/L ratio of aspartic acid in human dentine. The D/L ratios so determined were slightly lower than from the ion-exchange method with respect to all dentines examined. However, there were little or no significant differences in the ages estimated by both methods, and the correlation coefficient of this method was 0.982. The method is suitable for the enantiomeric analysis of amino acids, and has several advantages in the technique and time.

Adult↗
PubMed1988

Activated carbon as a biological model: comparison between activated carbon adsorption and oil-water partition coefficient for drug activity correlation.

Octanol-water partition coefficients have been used as a principal parameter for the analysis of quantitative structure-activity relationships (QSAR). With ionized drugs, however, the correlation is not impressive. Although clinical local anesthetics exist mainly in the ionized form at physiological pH, the nerve-blocking potency is correlated with the oil-water partition coefficients of the un-ionized species. In the present report, the adsorption of 18 local anesthetics onto activated carbon surfaces was compared with oil-water partition coefficients for correlation with the minimum nerve-blocking (MBC) potency. The log octanol-water partition coefficients showed large differences between the charged and uncharged species (lidocaine: 0.49 and 1.82, procaine: -0.56 and 1.74, respectively), whereas the log carbon surface adsorbabilities showed much smaller differences (lidocaine: 3.00 and 3.04, and procaine 2.95 and 3.00, respectively). An excellent correlation was found between the log carbon surface adsorption and the log MBC values in both ionized and un-ionized drugs.

Adsorption↗
PubMed1988

Glucose tolerance in middle-aged Japanese males with uncomplicated hypertension.

Plasma glucose levels in 50 g oral glucose tolerance test (OGTT) were compared between uncomplicated hypertensives (n = 507, mean age = 48 +/- 0.3 years) and normotensives (n = 378, mean age = 46 +/- 0.3 years). The subjects were selected in a systematic way from 10,120 male employees in a work-site population in Japan. None of hypertensives took any antihypertensive drugs. Plasma glucose levels at each time point of OGTT were significantly higher in the hypertensives than in the normotensives when the differences in age, obesity, and other factors that might influence glucose metabolism were adjusted, using multiple linear regression analysis. Similarly, multiple regression analysis for subjects including both normotensives and hypertensives revealed a significant relationship between plasma glucose levels and blood pressure, which was independent of age and body mass index. These findings indicate a more direct association between hypertension and hyperglycemia, which is not mediated via aging or obesity.

Blood Glucose↗
PubMed1988

Increased intratumor concentration of fluorescein-isothiocyanate-labeled neocarzinostatin in rats under angiotensin-induced hypertension.

On the basis of the observation that the tumor tissue blood flow selectively increases under angiotensin (AT)-induced hypertension, the change of the drug concentration in the tumor and normal tissues was examined in male Donryu rats. The intratumor concentration of fluorescein isothiocyanate-labeled neocarzinostatin was about 2-fold higher in the AT-induced hypertension group than in the control up to 20 min after the drug injection. In the normal organs or the uninvolved organs of the tumor-bearing rats, however, no clear increase was seen in the experimental group compared with the control, as anticipated from the observation of the tissue blood flow. The present study supports the hypothesis that the enhanced anticancer effect in chemotherapy under AT-induced hypertension formerly reported is due to the tumor-selective enhancement of the drug delivery.

Angiotensin II↗
PubMed1988

Long-term prognosis of malignant hypertension; difference between underlying diseases such as essential hypertension and chronic glomerulonephritis.

A long-term prognosis was studied in 69 patients with malignant hypertension, followed for an average of 56 months. Overall survival rate was 90% for a 5-year period, although the prognosis was different between two major underlying diseases, namely the 5-year survival was 79% for 33 essential hypertension (EHT) and 100% for 26 chronic glomerulonephritis (CGN); the difference is significant (p less than 0.01). In contrast, the 5-year rate for renal survival, defined as the probability of surviving without hemodialysis, was 37% in all cases. However, there was significant difference in the renal survival between EHT (60% for a 5-year period) and CGN (4% for a 18-month period). Multivariate analyses of the Cox's proportional hazards model revealed that the long-term change in renal function was different between the two groups, namely more rapid deterioration in the CGN group. These results indicate that a long-term prognosis of malignant hypertension is influenced by the underlying diseases and hemodialysis besides antihypertensive treatment may increase survival in malignant hypertension associated with severely damaged renal function.

Adult↗
PubMed1987

Pathophysiology in malignant hypertension: with special reference to the renin-angiotensin system.

Pathophysiology of malignant hypertension, of which underlying disease was essential hypertension (EHT) in 33 cases and chronic glomerulonephritis (CGN) in 26 cases, was studied with reference to the renin-angiotensin system. Plasma renin activity (PRA) was significantly higher in the EHT than in the CGN group, and angiotensin II antagonist [Sar1, Ile8]angiotensin II (AIIA) induced a significant lowering of blood pressure only in the former group. PRA was linearly correlated with both pretreatment mean blood pressure (MBP, r = 0.474, n = 29, p less than 0.01) and serum creatinine (r = 0.540, n = 29, p less than 0.01) in the EHT group but not in CGN patients, although there was an inverse correlation between PRA and serum sodium in both groups. Multiple regression analysis revealed that PRA was independently related to MBP, serum creatinine, and serum sodium in the EHT group, but not in the CGN group. These results suggest that the renin-angiotensin system plays a significant role in elevating blood pressure and deteriorating renal function in malignant hypertension derived from EHT, but it is less important in CGN related hypertension.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1987

Sodium and vasopressin modulation of renal sympathetic nerve activity.

A series of correlative studies show that sympathetic renal nerve activity (RNA) may be influenced by the concentration of sodium (Na+) in the plasma and the cerebrospinal fluid (CSF). Further study of the sites and characteristics of the interaction between Na+ and the renal nerves was undertaken in anesthetized dogs. Cerebroventricular (i.c.v.) injections of hypertonic sodium chloride (NaCl) produced a sympathetic vasoconstrictor response associated with tachycardia, increases in plasma norepinephrine and vasopressin (AVP), and a decrease in the electroneurographic activity recorded from post-ganglionic renal sympathetic nerves. Both bilateral vagotomy and intravenous administration of an AVP antagonist prevented the decrease in RNA caused by i.c.v. hypertonic NaCl, without markedly reducing the magnitude of the pressor response. The same phenomenon, however, could not be duplicated by delivery of the AVP antagonist i.c.v. In another group of dogs, the pressor activity of NaCl injected into the cisterna magna was compared before and after surgical ablation of the area postrema in the dorsal medulla. Removal of this circumventricular organ attenuated the pressor effects of NaCl given into the cisterna magna, but not those produced by i.c.v. delivery of the injectate. The data suggest that acute increases in CSF Na+ cause a differential activation of the sympathetic nervous system mediated in part by structures at or near the area postrema. At this site, circulating AVP apparently augments the inhibitory input from vagal afferents on the preganglionic renal nerve neurons.

Animals↗
PubMed1987

Single oral administration of captopril may not bring an improvement in screening of primary aldosteronism.

Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured in 19 cases with primary aldosteronism (PA) and 72 with essential hypertension (EHT) to differentiate the two disorders in the following conditions: after overnight recumbency (basal state) and after oral administration of captopril. Screening criteria were determined in order to pick up all of PA patients as positive. After the captopril administration, the specificity of a criterion based on the combination of PAC and PAC/PRA ratio was 93% and positive predictive value 79%. This criterion was superior to other conventional screening methods. However, higher specificity (97%) and positive predictive value (90%) were obtained from a combination criterion based on the basal PAC and PAC/PRA ratio. The single oral administration of captopril may not bring an improvement in the screening of PA.

Aldosterone↗
PubMed1987

[Intravital observations on the development of the tumor vascular system in rats].

By using transparent chambers in rats, it proved possible to observe directly the normal vascular pattern and early neovascular response to solid tumor growth at high magnification. Morphologic studies of the vascularization patterns were performed daily by construction of photomontages from color instant film taken with a Polaroid camera. Noteworthy results obtained in this study were: In the normal subcutaneous tissue within the chamber, the main vascular pattern was similar to that described by Nicoll and Webb, showing the so-called "arcuate arteriolar pattern". The thoroughfare channel reported by Chambers and Zweifach was also observed. The establishment of new functional capillaries was observed within 2 weeks following the implantation of AH109A and AH272 tumors. The sprouts of newly formed vessels were seen originating at the arterial ends of the host capillaries, where the blood velocity was relatively high. The formation of intricate networks in the tumor occurred easily in a haphazard way; the three modes of network formation observed were sprouting, cross-connection and splitting. Progressive dilatation and tortuosity were observed in the preexisting vessels, especially capillaries and venules, in the neighborhood of the tumor implant. The arterioles, however, remained little altered and in a location almost identical to that at the time of tumor implantation. The vascular systems in the tumors were proved to parallel those in the normal organs from which they originated, from the microfocus stage to the large tumor stage. An understanding of the differences in the vascular architecture between normal and tumor tissue seems to be essential in order to elucidate the mechanism of enhancement of therapeutic effect by angiotensin II induced hypertension chemotherapy.

Animals↗
PubMed1987

A rapid and sensitive analytical procedure for human plasminogen subspecies. Combination of high-performance affinity chromatography and specific monitoring of proenzymes.

Human plasminogens specifically separated by high-performance affinity chromatography were specifically detected by a newly devised, on-line monitoring system, in which the proenzymes were activated by urokinase and plasmin activity thus generated was assayed. Presence of Lys-plasminogen as a constituent in the blood was demonstrated by both chromatographic patterns and biochemical experiments. This system made it possible to estimate rapidly not only Glu-plasminogen but also Lys-plasminogen in the plasma without any pretreatment. Its utility as a tool for clinical analysis of fibrinolytic system was suggested.

Chromatography, High Pressure Liquid↗