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Biomedical subjects

S Baba

Publications and source records attributed to S Baba.

At least 469 records · Page 26Linked to original sources
PubMed1992

Therapeutic effects of liposomal adriamycin in combination with tumor necrosis factor-alpha.

Liposomes as drug carriers in cancer chemotherapy have attracted considerable interest. To enhance the therapeutic effect of Adriamycin entrapped in liposomes (Lip-ADM) on human solid tumors, we investigated the therapeutic effects of Lip-ADM in combination with recombinant human tumor necrosis factor-alpha (rTNF-alpha), which is known to have specific effects on tumor vasculature. rTNF-alpha or saline solution was injected intravenously into nude mice bearing a human colon cancer strain, HC-1, at 1 hour before intravenous administration of Lip-ADM. The significant therapeutic effect of Lip-ADM in combination with rTNF-alpha was demonstrated by the evaluation with tumor growth curve and the actual tumor weights, in comparison with groups of mice treated with saline solution, rTNF-alpha alone, or with a Lip-ADM after saline. Levels of Adriamycin in tumor tissue in the Lip-ADM in combination with rTNF-alpha-treated group were higher than those in Lip-ADM with saline solution-treated group.

Animals↗
PubMed1992

Effect of liposomal interleukin-2 on ascites-forming rat hepatoma.

Interleukin-2 was entrapped in liposomes (Lip-IL-2) and injected into rats. The intraperitoneal injection of Lip-IL-2 into rats bearing an ascites-forming rat hepatoma (AH-66) significantly increased the survival time when compared with rats administered free IL-2 or saline-containing liposomes. The number of peritoneal exudate cells (PEC) increased markedly after intraperitoneal injection of Lip-IL-2 and consisted mainly of macrophages. The level of tumor necrosis factor alpha (TNF-alpha) and the intensity of free radicals increased in the ascites at 48 hrs after Lip-IL-2 administration, whereas TNF-alpha was not detected and the intensity of free radicals did not increase after free IL-2 administration. Our findings suggested that entrapment of IL-2 into liposomes enhanced its potential for cancer therapy, presumably by activating macrophages to produce TNF-alpha and free radicals.

Animals↗
PubMed1992

Portal vein thrombosis after splenectomy successfully treated by an enormous dosage of fibrinolytic agent in a short period: report of two cases.

Portal vein thrombosis (PVT) after splenectomy in a patient with portal hypertension occurs with unusually high frequency. Recently, two patients with PVT following splenectomy were treated by fibrinolytic therapy with an enormous dosage of urokinase (UK) in a short period. PVT was quickly dissolved without side effects and the patients are now doing well without any recurrence of PVT. Therefore, when there is no evidence of bowel infarction, fibrinolytic therapy with an enormous dosage of UK over a short period is deemed to be both effective and essential as a conservative therapy for PVT.

Adult↗
PubMed1992

Aggressive repeat liver resection for hepatic metastases of colorectal carcinoma.

Although hepatectomy for liver metastases from colorectal carcinoma is an effective treatment, recurrence in the liver is still the most common site after hepatectomy. Thirty patients underwent hepatectomy for hepatic metastases and 17 of them had recurrence in the remnant liver during the following 12-year period. Six of the 17 patients underwent a removal of isolated hepatic recurrences. Two of the six patients underwent a third hepatectomy, and three patients underwent partial lung resection on a total of five occasions. There were no operative deaths while complications after a third hepatectomy contributed to a high morbidity rate of 40 per cent. The mean length of survival of the six patients was 28.5 months from the second hepatectomy. The prognosis of the six patients who underwent a repeat hepatectomy was significantly better than that of patients with unresectable recurrence after an initial hepatectomy (p less than 0.01). The overall 5-year survival of 29 patients excluding one in-hospital death was 44.7 per cent. Our results reveal that aggressive removal of isolated and resectable recurrent disease has the potential to improve the prognosis of selected patients with metastatic cancer.

Adult↗
PubMed1992

Intraperitoneal amyloid formation by amyloid enhancing factor--rich macrophages in ascitic fluid.

Although resident peritoneal cells from amyloidotic mice (amyloidotic peritoneal cells) are capable of processing the precursor protein of secondary amyloidosis, serum amyloid A (SAA) to amyloid fibrils, the peritoneum is a rare site for amyloid deposition. This is considered to be due to a deficiency of SAA in the peritoneum. To increase the supply of SAA to the peritoneum, ascitic fluid containing about the same protein constituents as in the serum was induced in mice. Amyloidotic peritoneal cells were packed in a microchamber which was shielded with filter membranes, and cultured in ascitic fluid supplemented with additional inflammatory factors. On the 7th day, Congo red-positive structures which showed green birefringence under polarized light were found inside and occasionally outside the chamber. By anti-AA or -SAA immunostaining, amyloid deposits and the cell surfaces of macrophages were positive. Immunologic depletion of T- and B-lymphocytes from the amyloidotic peritoneal cells did not adversely effect the amyloid formation in microchambers. These results suggest that either ascitic fluid containing sufficient amounts of SAA, or peritoneal macrophages with a high amyloid enhancing factor (AEF) activity are indispensable for AA amyloid fibrillogenesis in the peritoneum.

Amyloid↗
PubMed1992

Structural requirements for the effects of neuropeptide Y on the hypothalamic-pituitary-adrenal axis in the dog.

Neuropeptide Y (NPY), administered into the third cerebral ventricle of the dog stimulates plasma ACTH and cortisol secretion. To further investigate the structure-activity relationships of this action, we examined the effect of COOH-terminal fragment, NPY 19-36 and its analogues, NPY-(1-36)-OH (deamidated NPY) and avian pancreatic polypeptide (APP) on ACTH-cortisol secretion following intracerebroventricular (i.c.v.) injection in the dog. NPY (1.19 nmol) evoked a significant increase in the secretion of both plasma ACTH and cortisol. However, NPY 19-36 and NPY-(1-36)-OH each failed to increase plasma ACTH and cortisol secretion at doses of 1.19-11.9 nmol injected i.c.v. APP was less active than NPY. These data demonstrate that the entire NPY molecule is required for the full expression of the stimulatory effect of NPY on the secretion of ACTH and cortisol.

Adrenocorticotropic Hormone↗
PubMed1992

Alcohol drinking and high blood pressure: data from a 1980 national cardiovascular survey of Japan.

Many epidemiological cross-sectional studies have confirmed that alcohol drinking is related to high blood pressure. However, the impact of alcohol drinking on high blood pressure in the general population including older people has only been reported on in a few studies. The association between alcohol drinking and blood pressure or the prevalence of hypertension was examined using cross-sectional data of 4795 men and 6102 women aged 30-94, randomly selected from the Japanese population in 1980. The response rates were 74 and 84% for men and women, respectively. The prevalence of hypertension adjusted for body mass index (BMI, kg/m2) was significantly higher in everyday male drinkers than in male non-drinkers from the youngest age group (30-39 years) to oldest age group (70 years and over). A relationship between alcohol and blood pressure was found only in the youngest age group (30-39 years) of female drinkers. In each 10-year age-group of men, the BMI-adjusted systolic and diastolic blood pressures in everyday drinkers were 7-10 and 4-6 mmHg higher than those in non-drinkers. The relationship between alcohol and blood pressure in men was confirmed by multiple regression analysis adjusting for age and BMI in both younger (30-59 years) and older (60-94 years) people. The impact of alcohol drinking on blood pressure in men should be taken into account in the primary prevention of blood pressure related diseases and in the treatment of hypertension in both younger and older people.

Adult↗
PubMed1992

Breakdown of hepatic tight junctions during reoxygenation injury.

We investigated whether reoxygenation following anoxia increased biliary permeability and whether or not allopurinol had a protective effect. Isolated rat livers were perfused for 30 min in a one-pass system with buffer equilibrated with 100% nitrogen after stabilization, and then for 60 min with the oxygenated buffer. Hepatic tight junction permeability was assessed by quantifying the early appearance in the bile of horseradish peroxidase (HRP) injected with the perfusate. This early peak represents paracellular passage of HRP, whereas a later second peak results from transcellular passage. In the control livers, 7% of the total HRP passage (93 +/- 50 pg/g liver) was paracellular and 93% was transcellular. After 30 min of reoxygenation following anoxia, however, 516 +/- 20 pg/g liver of HRP passed paracellularly. Addition of allopurinol (5 micrograms/ml) to the perfusate from the start of perfusion reduced paracellular passage of HRP to 219 +/- 49 pg/g liver after anoxia and reperfusion (P less than 0.01). Allopurinol also reduced the cumulative lactate dehydrogenase (LDH) release during the first 30 min of reoxygenation from 2.1 +/- 0.3 x 10(4) to 1.4 +/- 0.4 x 10(4) units/g liver (P less than 0.01). Reduction of the anoxic period from 30 min to 25 min significantly reduced the change in tight junction permeability and the extent of cellular injury: Paracellular passage of HRP was 336 +/- 20 pg/g and LDH release was 0.7 +/- 0.1 x 10(4) units/g liver, both significantly lower than those at 30 min (P less than 0.01). No significant difference in hepatic ATP levels after 60 min of reoxygenation was noted among the experimental groups, but all had lower levels than the control group. The protective effect of allopurinol suggests that the mechanism of biliary reoxygenation injury involves free radical generation. Susceptibility of tight junctions suggests a pattern of injury similar to that involved in anoxic damage of the vascular endothelium.

Adenosine Triphosphate↗
PubMed1992

Cell proliferative activity of epidermal keratinocytes in hair discs.

To clarify the differences in epidermal keratinocyte proliferative activity and in postnatal developmental changes of this activity between the hair discs and the interfollicular epidermis, the incorporation of 3H-thymidine into the nuclei of the basal cells was measured by autoradiography, and the percentages of basal cells thus labelled were calculated. This percentage was higher in hair discs than in interfollicular epidermis at all stages examined. The percentage of labelled basal cells in the hair discs was 10% up to 15 days after birth, decreasing to about 6% from 20 days postnatally. These results suggest that the degree of cell proliferation in the hair disc epidermis differs from that in the surrounding epidermis and that changes in proliferative activity during the postnatal developmental stages are well correlated with the morphogenesis of the hair discs.

Animals↗
PubMed1992

Alpha 1-adrenoceptor subtypes in the rat ventricular muscle.

Scatchard analyses of [3H]prazosin binding in rat ventricular muscle membranes showed biphasic curves, which identified alpha 1High- and alpha 1Low-affinity sites. The alpha 1High-affinity site was completely inhibited by 1 microM phenoxybenzamine. The displacement potencies of alpha 1-adrenergic antagonists were characterized by [3H]prazosin binding to alpha 1High- and alpha 1Low-affinity sites in the absence and presence of 1 microM phenoxybenzamine. The affinities of most chemicals for alpha 1Low-affinity sites were significantly lower than those for alpha 1High-affinity sites, but WB-4101 (2-(2,6-dimethoxy-phenoxyethyl)aminomethyl-1,4-benzodioxane), arotinolol, cinanserin, nifedipine, and p-aminoclonidine had the same affinities for both alpha 1Low- and alpha 1High-affinity sites. These results show that two alpha 1-adrenoceptor subtypes, alpha 1High- and alpha 1Low-affinity, are present in the rat heart, and that there are physical variations in alpha 1-adrenoceptor binding sites, based on their selectivity to antagonists.

Adrenergic alpha-Antagonists↗
PubMed1992

Alpha 1-adrenoceptor subtypes in bovine prostate.

The object of this study was to examine the existence and characteristics of alpha 1-adrenoceptor subtypes in the bovine prostate using the radioligand binding assay method. [3H]Prazosin was used as the radioligand and its binding sites in bovine prostate were classified into two subtypes. One subtype showed a high affinity (alpha 1High, Kd: 101.1 pM and Bmax: 11.8 fmol (mg protein)-1) and the other had a low affinity (alpha 1Low, Kd: 3371.4 pM and Bmax: 50.5 fmol (mg protein)-1). Although the same pKi values of clorethylclonidine, p-aminoclonidine, benoxathian and dibenamine to both alpha 1High and alpha 1Low binding sites in bovine prostate tissue were observed, other alpha 1 antagonists used in this study had different pKi values for the two alpha 1-adrenoceptor subtypes. The existence and binding characteristics of alpha 1-adrenoceptor subtypes in bovine prostate were clarified. It is possible that agents selective for one site may contribute to the development of better drugs for the treatment of bladder outlet obstructions of men with benign prostatic hyperplasia.

Animals↗
PubMed1992

Solubilization of high affinity peptide-YY receptors from porcine brain.

We have previously characterized peptide-YY (PYY) receptors in porcine hippocampal membranes. We demonstrate here that brain PYY receptors can be extracted in the active state using digitonin. Among several detergents tested for their suitability to extract active PYY receptors, digitonin gave the most favorable results, as judged by specific binding of [125I]PYY to the solubilized receptors. The binding of [125I]PYY to digitonin extract was dependent on incubation time, temperature, and protein and magnesium ion concentrations and had a pH optimum of 6-7. Solubilized PYY receptors maintained the rank order of potencies for various related peptides and PYY fragments characteristic of the membrane PYY receptor: PYY greater than neuropeptide Y (NPY) much much greater than avian and porcine pancreatic polypeptide, and PYY greater than PYY-(22-36) much much greater than PYY-(1-22) and PYY-(22-28), respectively. Scatchard analyses of competitive binding data indicated the presence of two classes of binding sites in the digitonin extract; the high affinity component had affinities and binding capacities similar to those of the membrane PYY receptor. Solubilized PYY receptors also retained their sensitivity to guanine nucleotides. PYY was cross-linked to its receptors with disuccinimidyl suberate, solubilized with digitonin, and cross-linked to digitonin-solubilized receptors. The resulting complexes were analyzed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by autoradiography. Using these procedures, we identified a PYY receptor species with a molecular size of 50,000, which was the same size as the labeled protein in native membrane homogenates. Solubilized NPY receptors were also the same size. The solubilized cross-linked PYY receptor was adsorbed by wheat germ agglutinin-agarose and Concanavalin-A, suggesting its glycoprotein nature. These data suggest that the specific binding properties of the PYY receptor are inherent in the solubilized glycoprotein molecules. The solubilization in digitonin of PYY receptors from membranes should allow a more complete molecular and functional characterization of PYY-mediated events and purification of the receptor.

Adsorption↗
PubMed1992

Carbohydrate structures of beta-core fragment of human chorionic gonadotropin isolated from a pregnant individual.

Highly purified beta-core fragment was obtained from urine of a pregnant woman with use of an immunoaffinity column. The amino acid sequence of beta-core fragment indicated that it is composed of two polypeptides linked by a disulfide bond. The two polypeptides correspond to the 6-40 and 55-92 portions of hCG beta-subunit. Both Asn13 and Asn30 residues were glycosylated. The N-linked sugar chains of beta-core fragment were quantitatively released as radioactive oligosaccharides by hydrazinolysis, followed by N-acetylation and NaB3H4 reduction. The radioactive oligosaccharides were fractionated by serial lectin column chromatography and Bio-Gel P-4 column chromatography, and their structures were investigated by sequential exoglycosidase digestion and periodate oxidation. The results indicated that they were a mixture of the four oligosaccharides: Man alpha 1----6(+/- Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4(+/- Fuc alpha 1----6)GlcNAc. The structural characteristics of the sugar chains of beta-core fragment are quite different from those of the beta-subunit of hCG whose structures were typical biantennary sugar chains containing the Neu5Ac alpha 2----3Gal beta 1----4GlcNAc beta 1----2 group as their outer chains.

Amino Acid Sequence↗
PubMed1992

Solubilization of the receptors for avian pancreatic polypeptide in chicken, canine, and pig brains.

When n-octyl-beta-D-glucoside was used in several detergents to extract active avian pancreatic polypeptide (APP) receptors, a specific binding of [125I]APP to the solubilized chicken cerebellar and porcine hippocampal membranes was found. The binding of [125I]APP to the solubilized receptors was dependent on incubation time, temperature, and protein concentrations and appeared to have a slightly acidic optimal pH. APP binding to chicken and porcine brain extracts showed a high specificity for APP, although the chicken receptors do not discriminate well between APP and its related peptides, neuropeptide Y and peptide YY. Scatchard analyses of competitive binding data indicated the presence of two classes of binding sites in the brain extracts as in membrane-bound receptors; however, the high affinity component of the chicken receptor showed a decreased affinity after extraction. APP receptors in chicken and porcine brain extracts retained their insensitivity to the nonhydrolyzable GTP analog guanosine 5'-O-(3-thiotriphosphate). Cross-linking studies were performed with the homobifunctional cross-linker disuccinimidyl suberate and brain membrane receptors solubilized with n-octyl-beta-D-glucoside. An APP receptor species with a M(r) of 67,000, the same size as that of the labeled protein in native membrane homogenates of chicken and pig brains, was identified. However, in the canine brain we observed a M(r) 85,000 receptor protein, suggesting that species differences exist among the structures of brain APP receptors. The solubilized cross-linked APP receptors in these species were adsorbed by wheat germ agglutinin-agarose and by concanavalin A, indicating that they are glycoprotein in nature. The availability of the solubilized receptors from vertebrate brains with n-octyl-beta-D-glucoside represents an important step toward the purification and molecular characterization of the APP receptors.

Animals↗
PubMed1992

Evidence for further heterogeneity of the receptors for neuropeptide-Y and peptide-YY in tumor cell lines derived from neural crest.

The expression and structure of the receptors for neuropeptide-Y (NPY) and peptide-YY (PYY) were studied in 16 human and rodent tumor cell lines derived from the neural crest by ligand binding and cross-linking techniques using [125I]Bolton-Hunter-NPY, [125I]PYY, and various forms of monoiodinated NPY and PYY. Although NPY-binding sites were observed in most of the tumor cells, PYY-binding sites were found only on the human neuroblastoma cell lines SMS-MSN, SMS-KAN, SK-N-MC, and MC-IXC and the human Ewing's sarcoma cell line SK-ES. The differential labeling of the NPY/PYY receptors on these cell lines suggests that the NPY/PYY receptors are more heterogeneous than previously described as the Y1, Y2, and Y3 receptor subtypes. Cross-linking studies demonstrate that the Y1 and Y2 receptors for NPY/PYY are structurally different (mol wt, 70 and 50 kilodaltons, respectively) and that the 70- and 50-kilodalton receptor proteins are coexpressed in certain tumor cell lines. This could explain at least in part why cell lines show a relative specificity for Y1/Y2 classification, observed as the inhibition by both C-terminal fragments and Y1-specific analogs on the NPY/PYY binding to membrane receptors. Collectively, the present study suggests further heterogeneity of the NPY/PYY receptors and the existence of multiple receptor proteins in the tumor cell lines derived from the neural crest.

Animals↗