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Biomedical subjects

S Baba

Publications and source records attributed to S Baba.

At least 505 records · Page 28Linked to original sources
PubMed1991

Ethanol stimulates pepsinogen release by opening a Ca2+ channel of guinea pig gastric chief cells.

To better understand the mechanism by which ethanol causes gastric mucosal injury, the effects of ethanol on isolated guinea pig gastric chief cells were investigated in vitro. Ethanol at 300-900 mmol/L dose-dependently stimulated an increase in pepsinogen release without affecting chief cells' viability. Ethanol stimulated an increase in initial Ca2+ influx rate and intracellular Ca2+ concentration at the same concentrations as it stimulated pepsinogen release, whereas it did not stimulate cyclic adenosine monophosphate accumulation. Pepsinogen release stimulated by 900 mmol/L ethanol was almost equal to that stimulated by 10(-8) mol/L COOH terminal octapeptide of cholecystokinin. Ethanol did not stimulate an increase in the accumulation of inositol trisphosphates and tetrakisphosphates in [3H]inositol-labeled chief cells, whereas cholecystokinin octapeptide caused a significant increase in inositol trisphosphates and tetrakisphosphates. Ethanol-stimulated pepsinogen release and increases in the initial Ca2+ influx rate and intracellular Ca2+ concentration were inhibited by 0.5 mmol/L La3+ or 1 mmol/L ethylene glycol tetraacetic acid but were not inhibited by nifedipine or verapamil. These results suggest that the effect of ethanol on pepsinogen release from the gastric chief cells may be due to its opening of a Ca2+ channel that is sensitive to La3+ and that the pepsinogen releasing action of ethanol may be one of factors for ethanol-induced gastric mucosal injury.

Animals↗
PubMed1991

Effects of dietary glucose or fructose on the secretion rate and particle size of triglyceride-rich lipoproteins in Zucker fatty rats.

Effects of dietary carbohydrate on the secretion rate and particle size of triglyceride-rich lipoproteins were examined in Zucker fatty rats fed fructose and glucose and were compared with those of Zucker lean rats. Carbohydrates were supplied as 10% drinking solutions for 14 days. As compared with lean rats, Zucker fatty rats had hyperinsulinemia and hypertriglyceridemia associated with an increased rate of triglyceride secretion into the circulation. Feeding fructose and glucose to fatty rats produced an increase in plasma glucose levels, whereas plasma insulin concentrations did not show significant changes. Neither fructose nor glucose supplementation produced significant changes in the rate of triglyceride secretion. Despite this, plasma triglyceride concentrations in fructose-fed fatty rats were twice as high as those in glucose-fed rats or those receiving no supplementary carbohydrate. Particle diameters of lipoproteins of density between 0.96 and 1.006 were larger in fructose-fed fatty rats than in those receiving no sugar. The results suggest that feeding fructose, but not glucose, into fatty rats is associated with an impairment of triglyceride removal and a resultant increase in plasma triglyceride concentration, the latter of which is accompanied by an increase in triglyceride contents in each particle.

Animals↗
PubMed1991

Effects of long-term high-fiber diet on macrovascular changes and lipid and glucose levels in STZ-induced diabetic SD rats.

The effects of long-term high-fiber diet on lipid and glucose levels and the histological changes in the coronary arteries and thoracic aorta in STZ-induced diabetic SD rats were investigated. During the first 4 weeks of the study period, all diabetic rats were given regular chow plus water after which, all were grouped according to the following diet regimen: group II, no added cholesterol and glucomannan; group III, no added cholesterol but with glucomannan supplement, group IV, with added cholesterol but no glucomannan supplement; and group V, with both cholesterol and glucomannan supplements. 15% weight of glucomannan and 1.5% weight of cholesterol in regular rat chow were used as supplements when indicated. Non-diabetic rats which received only regular chow served as the control group (group I). In the 18th week all rats were sacrificed and weight gain, glucose, total cholesterol, HDL-cholesterol, triglyceride and lipid peroxidase concentrations were determined. Selected portions of the heart and thoracic aorta were histologically examined. Weight gain was higher in rats supplemented with glucomannan than in those without glucomannan supplements, but the difference is not significant. A lowering tendency in glucose levels was likewise observed. Furthermore, total cholesterol and HDL-cholesterol levels were lower and higher, respectively in diabetic rats receiving glucomannan. Although the triglyceride levels were similar in all rats, lipid peroxidase levels were significantly lower in rats with high-fiber diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Effect of the cooling rate on insulin release from frozen-thawed In-111 cells.

Cultured cells derived from hamster insulinoma (In-111 R1 cells) were placed in 1.4 M dimethyl sulfoxide (Me2SO)-containing RPMI 1640 at 20 degrees C for 20 min. They were frozen to -40 degrees C at a cooling rate of 1.0 or 0.5 degrees C/min, subsequently to -80 degrees C at 3 degrees C/min with a programmable freezer. After being maintained at -80 degrees C, they were rapidly thawed to 37 degrees C. Thawed cells were washed with 0.75 M sucrose for removal of Me2SO. Recovered cells were cultured in 2 ml of RPMI 1640 with 1.3 mM theophylline under a gas phase of 95% air -5% CO2 at 37 degrees C for 2 days. In both cooling rates, frozen-thawed cells discharged more insulin than the thawed in the absence of theophylline. However, this released insulin level was higher in the cells frozen at a cooling rate of 0.5 degrees C/min than that at 1.0 degrees C/min. Moreover, insulin released from frozen-thawed hamster insulinoma cells increased significantly with the addition of 1.3 mM theophylline. Considering that the higher insulin release level at 11.1 mM glucose alone might indicate cellular damage, it is suggested that the cooling rate of 1 degree C/min may be better for cryopreservation of the dispersed cells under the present protocol for the assessment of the function of insulin release.

Animals↗
PubMed1991

Structures of the asparagine-linked sugar chains of human chorionic gonadotropin from a patient with extragonadal germ cell tumour.

Human chorionic gonadotropin (hCG) purified from the urine of a male patient with extragonadal germ cell tumour contained four asparagine-linked sugar chains in one molecule. The sugar chains were quantitatively released from the polypeptide moiety by hydrazinolysis and recovered as oligosaccharides after N-acetylation. The oligosaccharide mixture was separated into a neutral (N) and three acidic (A1, A2 and A3) fractions by anion-exchange column chromatography. By sequential exoglycosidase digestion, methylation analysis and lectin column chromatography, the structures of these oligosaccharides were found to be the same as those of female gestational choriocarcinoma hCGs. Both contain eight kinds of sugar chains: triantennary, abnormal and normal biantennary, and monoantennary complex-type sugar chain with or without a fucosylated core portion.

Adult↗
PubMed1991

Multivariate analysis of flow cytometric deoxyribonucleic acid parameters and histological features for prognosis of bladder cancer patients.

We studied whether flow cytometry provides significant prognosticators beyond the classical histological evaluation in the patient with bladder cancer. A total of 203 patients with untreated bladder cancer was evaluated using fresh bladder tumor specimens. Tumor grading and stage were the histological prognostic parameters. Deoxyribonucleic acid (DNA) index, percentage S-phase cells, percentage G2/M-phase cells and hypertetraploid cell presence were assessed as flow cytometric prognostic parameters. Multivariate survival analysis was performed using Cox's proportional regression model to study statistical individual prognostic values of histological and flow cytometric parameters. Hypertetraploid cell presence was the single most important prognostic factor (p less than 0.01), with tumor grade being nearly as important (p less than 0.01), followed by tetraploidy (p less than 0.01) and tumor stage (p less than 0.05). No other parameters, including the DNA index or cell phase fractions, contributed to the model. These results indicated that combined use of histological and flow cytometric parameters may provide additional information regarding the clinical outcome for bladder cancer patients.

Adult↗
PubMed1991

Quantification of cell kinetic characteristics using flow cytometric measurements of deoxyribonucleic acid and bromodeoxyuridine for bladder cancer.

A total of 56 human bladder tumors that were histologically proved to be transitional cell carcinoma was analyzed by simultaneous flow cytometric 2-color measurements of deoxyribonucleic acid (DNA) and bromodeoxyuridine. Bromodeoxyuridine in vitro labeling was performed by sample incubation with bromodeoxyuridine under high atmospheric pressure oxygen. Grade 1 tumors showed 33.3% aneuploidy with a mean bromodeoxyuridine positive stained ratio (labeling index) of 5.1 +/- 3.4%. Grade 2 tumors featured 51.7% aneuploidy with a mean labeling index of 8.9 +/- 7.7%. On the other hand, a markedly increased labeling index of 15.2 +/- 8.2% with aneuploidy was observed in all but 1 grade 3 tumors. When DNA ploidy and labeling indexes were compared according to the presence or absence of muscular invasion of tumors, all 16 muscle invasive tumors showed aneuploidy (mean labeling index 18.7 +/- 8.0%), while 17 of 40 nonmuscle invasive tumors showed aneuploidy (mean labeling index 8.6 +/- 5.4%). This labeling index difference was statistically significant (p less than 0.01). These results indicate that bromodeoxyuridine/DNA 2-color flow cytometry may provide an objective parameter for quantification of the malignant potential of bladder cancers.

Aneuploidy↗
PubMed1991

Efficacy of gadolinium-diethylenetriaminepentaacetic acid-enhanced magnetic resonance imaging for differentiation between superficial and muscle-invasive tumor of the bladder: a comparative study with computerized tomography and transurethral ultrasonography.

Gadolinium-labeled diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) was evaluated in an effort to clarify whether MRI could replace or be proved to be superior to computerized tomography (CT) and/or transurethral ultrasonography. A total of 57 bladder cancer patients was evaluated. MRI was performed with a superconducting magnet operating at 1.5 Tesla. The images acquired were multisections, having a fast spin-echo pulse sequence of less than a 14-second breath holding. Serial scans were performed before and immediately after Gd-DTPA venous injection. The findings on different imaging techniques were compared with the histological stagings. A proper diagnosis was made in 42 of 57 cases (73.7%) by Gd-DTPA-enhanced MRI, in 27 of 57 (47.4%) by CT and in 31 of 57 (54.4%) by transurethral ultrasonography when comparing the histological findings. The sensitivity and specificity for differentiating superficial and muscle-invasive tumor of each imaging method were, respectively, 96.2 and 83.3% in Gd-DTPA-enhanced MRI, 96.0 and 58.3% in CT, and 88.0 and 66.7% in transurethral ultrasonography. These data suggest that the staging of bladder cancer by Gd-DTPA-enhanced MRI appears to be superior and more accurate than the staging obtained by CT and transurethral ultrasonography.

Adult↗
PubMed1991

Pleomorphic adenoma of the external auditory canal in Japan, with a case report.

A rare case of a 51-year-old female with a pleomorphic adenoma, measuring 0.9 x 0.7 x 0.6 (cm3), originating from the right external auditory canal (EAC), was reported. The authors discussed the 7 reported cases of EAC pleomorphic adenoma in Japan, comparing them with pleomorphic adenomas occurring in the nasal cavity and the parotid gland. It is currently too early to conclude that pleomorphic adenoma in the EAC does not tend to recur or shows a marked tendency toward canceration. The best possible treatment for EAC pleomorphic adenoma at present seems to be, as in cases of tumors in other sites, surgical resection together with removal of a sufficient range of surrounding normal tissue, followed by careful long-term postoperative observation of the clinical course.

Adolescent↗
PubMed1991

The beneficial effect of a prostaglandin I2 analog on ischemic rat liver.

This study was undertaken to determine whether or not prostaglandin I2 (PGI2) analog pretreatment could successfully preserve organ viability after warm hepatic ischemia in rats. Although 120-min ischemia of the liver did not permit survival in rats administered normal saline solution (NS group) before warm ischemia, the survival rate of PGI2 analogue (500 ng/kg/min)-treated rats (PG group) significantly improved to 57% (P less than 0.05). Recirculation following 120-min hepatic ischemia in the NS group resulted in no improvement of B-phosphorus of the ATP (B-ATP)/inorganic phosphate (Pi) ratio measured by 31P nuclear magnetic resonance, a marked increase in the serum aspartate aminotransferase (SAST) level, and an increase in the malondialdehyde (MDA) level in liver tissue. In the PG group, the B-ATP/Pi ratio was significantly improved (P less than 0.05), the elevation in SAST was also markedly suppressed (P less than 0.05), and the MDA level of the liver was lowered more than that in the NS group. Severe congestion and extensive vacuolization of hepatocytes from the peripheral to the midzonal areas were histologically exhibited with single-cell necrosis in the NS group. There were fewer histological alterations of the liver and these coincided with the changes in other parameters in the PG group. Our results indicate that PGI2 analog reduces warm ischemic injury of the liver and provides greater protection for organs to be transplanted.

Animals↗
PubMed1991

Changes in dopamine2 and serotonin2 receptors in rat brain after long-term verapamil treatment: comparison of verapamil and lithium.

Rat brain 5-HT2 and dopamine2 receptors were assessed following a chronic (3 weeks) administration of verapamil, lithium, and a combination of these two drugs. A significant increase in the number of 5-HT2 receptors was observed in the frontal cortex after the verapamil treatment, but the lithium and combined treatment had no effect on the densities of either binding sites. These data suggest that one or more of the mechanisms of the antimanic effect of verapamil may be involved in the change in 5-HT2 binding sites in a manner that is different from that of lithium.

Animals↗
PubMed1991

Neuropeptide regulation of feeding in dogs.

Norepinephrine and four families of neuropeptides, namely, neuropeptide Y (NPY), opioid peptides, galanin, and growth hormone-releasing factor (GRH), have been shown to stimulate feeding after central administration. Because these studies were mainly done on laboratory rats, the present study was designed to ascertain the central stimulators of feeding in dogs. We have shown that porcine and human pancreatic polypeptides (PPs), when administered into the third cerebral ventricle (intracerebroventricularly), increased food and water intake of satiated animals but that the COOH-terminal fragments [hPP-(18-36) and hPP-(23-36)] did not do so at the same molar dose (11.9 nmol). The kappa-opioid receptor agonist dynorphin (A-(1-17) also stimulated food and water intake, whereas alpha-neoendorphin and Met-enkephalin did not. These results suggest the structural specificity of PPs and dynorphin peptides for stimulating feeding. Surprisingly, neither intracerebroventricular injections of NPY and peptide YY nor intracerebroventricular pretreatment with anti-hNPY gamma-globulin modulated feeding, stressing the species differences in the feeding response to exogenous substances and the underlying physiology. Intracerebroventricular injections of norepinephrine, GRH, galanin, and pancreastatin also failed to increase food intake, although most substances tended to or did increase water intake. These results suggest that neuropeptides play a role in a species-specific way in modulating appetite regulation.

Animals↗
PubMed1991

Relationship between auditory brainstem response waveform and head size.

The relationship between the head size and the latency and amplitude of the auditory brainstem response (ABR) was investigated in 60 normal-hearing adults (30 males and 30 females). We found a strong positive correlation between the latency of ABR waves and the head size and a strong negative correlation surfaced between the ABR amplitude and head size. These results indicate that the head size is one of the most important factors influencing the waveform of the ABR.

Adolescent↗
PubMed1991

Antitumor effects of interleukin 2 against renal cell carcinoma: basic study and clinical application.

In order to determine an optimum mode for systemic administration of recombinant interleukin 2 (rIL2), the effects of rIL2 on lymphocyte-mediated cytotoxicity against renal carcinoma cells were studied in vitro. Augmentation of the cytotoxicity by rIL2 was dose- and time-dependent. The optimum dose of rIL2 was 100-500 units (Jurkat units)/ml, and cytotoxicity increased significantly even at a low concentration such as 4 units/ml. We thus chose daily administration of multiple repeated dose for inpatients. To prevent withdrawal from the therapy as a result of untolerable adverse effects, the daily dose was set at 1 X 10(6) units, and rIL2 was given to 12 patients with metastatic renal cell carcinoma. Two-hour intravenous drip infusions containing 5 X 10(5) units of rIL2 was given daily 2 times to inpatients and after at least 28 days of this mode of administration, subcutaneous injection at a dose of 1 X 10(6) units was given 6 days a week to outpatients. Three patients showed complete response, 7 patients no change, and 2 patients progressive disease. Serious adverse effects due to capillary leak syndrome were not observed. We conclude that low-dose rIL2 is safe and has potential antitumor effects.

Aged↗
PubMed1991

Inhibitory effects of catechol derivatives on arachidonic acid-induced aggregation of rabbit platelets.

Pyrocatechol and other non-substituted dihydric phenols, which have strong redox power, inhibited arachidonic acid-induced aggregation of rabbit platelets at much lower concentrations than those at which these phenols inhibited stable prostaglandin endoperoxide, U46619-induced aggregation. Among non-substituted dihydric phenols, pyrocatechol was most potent. In order to clarify the physicochemical properties of the phenolic compounds which control the inhibitory potencies of dihydric phenols, we observed the inhibitory effects of 3- and 4-substituents of pyrocatechol on arachidonic acid-induced platelet aggregation. Among seven derivatives tested, the inhibitory effect of 4-C6H5-substituent was strongest and 4-COOH-substituent was weakest. Inhibitory effects of the catechol derivatives were well correlated with the quotients of their hydrophobicities and oxidation-reduction potentials. Inhibitory effects of hydroquinone and resorcinol were also on the same correlation line. These results suggest that the inhibitory effects of catechol derivatives and other dihydric phenols are controlled by two physicochemical properties: oxidation-reduction potential and hydrophobicity.

Animals↗
PubMed1991

Comparison of alpha 1-adrenoceptors between rat brain and spleen.

Scatchard analyses of 3H-prazosin binding in rat brain membranes showed biphasic curves, which identified the presence of alpha 1High- and alpha 1Low-affinity sites. The alpha 1High-affinity site was completely inhibited by 0.1 microM phenoxybenzamine. On the other hand, 3H-prazosin binding in rat spleen membranes resulted in linear curves that were identical to the binding curve for the alpha 1High-affinity site in the brain. The displacement potencies of alpha 1-adrenergic antagonists were characterized by 3H-prazosin binding to alpha 1High-affinity sites in the rat spleen and brain and alpha 1Low-affinity sites in the brain in the presence of 0.1 microM of phenoxybenzamine. The affinities of WB-4101, phenoxybenzamine, phentolamine, chlorpromazine, labetalol and nifedipine for brain alpha 1High-affinity sites were significantly higher than those in the spleen. The affinities of most ligands for alpha 1Low-affinity sites were significantly lower than those for both alpha 1High-affinity sites in the brain and spleen, but chlorethylclonidine was significantly selective for alpha 1Low-affinity sites, and bunazosin, dibenamine and 5HT had the same affinities for the alpha 1Low- and both alpha 1High-affinity sites. These results show that two alpha 1-adrenoceptor subtypes, alpha 1High- and alpha 1Low-affinity, are present in the rat brain and that a different alpha 1High-subtype, exists in the rat spleen.

Adrenergic alpha-Antagonists↗