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Biomedical subjects

Y Masuda

Publications and source records attributed to Y Masuda.

At least 595 records · Page 33Linked to original sources

[A simple multiple maze test to estimate learning and memory in mice: application to the effect of scopolamine on learning and memory].

The apparatus consists of a home cage, a maze cage and a starting box. A maze with four right-middle-left decisions was placed in the maze cage. The starting box was attached and a water tap was placed at an area corresponding to the entrance of the maze. The exit of the maze and the home cage are connected with a tunnel. Food was placed in the home cage. 1) Mice were housed for 10 hr a day in the apparatus and then removed to another cage for fasting. One trial a day was carried out after fasting for more than 12 hr. In each trial, a mouse was put at the starting box, and then the number of errors (entering a blind alley) and the time until the mouse reached the home cage were counted. The mouse passed through the maze with a small number of errors and time. 2) Administration of scopolamine (0.125-0.5 mg/kg, i.p.) to a mouse that had mastered the maze transiently disturbed the maze performance dose-dependently. 3) Mice were housed for 4 hr a day. Scopolamine (0.25 mg/kg, i.p.) was administered either before or after the housing. Scopolamine disturbed the maze performance in the case of both procedures. These results suggest that the method is useful for estimating the memory in mice.

Animals↗

Histological detection of lipid peroxidation following infusion of tert-butyl hydroperoxide and ADP-iron complex in perfused rat livers.

Lipid peroxidation was assessed histologically and biochemically in hemoglobin-free perfused rat livers using two different types of stimulators. The Schiff reaction of fuchsin with cellular aldehydes was used as a histological index for lipid peroxidation. t-Butyl hydroperoxide (BHP, 0.8 mM) infusion caused a rapid and sustained release of thiobarbituric acid reactive substances (TBARS) into the effluent perfusate for up to 60 min, which was accompanied by lactate dehydrogenase (LDH) leakage after 30 min. The Schiff positive foci were initially restricted to periportal zones and spread with time to whole areas, accompanied by periportal necrosis. Coinfusion of diphenyl-p-phenylenediamine suppressed the TBARS release, with negative fuchsin staining, but the LDH leakage was unaffected. Under retrograde perfusion, BHP produced pericentral staining and necrosis. With 2.5 mM ADP-100 microM Fe3+, little TBARS was released up to 60 min, even though the hepatic TBARS levels increased considerably by this time. By 90 min, marked TBARS release occurred, but LDH leakage remained low. Irrespective of the direction of perfusion, pericentral hepatocytes became Schiff positive after 30 min. The fuchsin staining method may be useful for detecting peroxidized zones of the liver lobules.

Adenosine Diphosphate↗

Histological evidence for dissociation of lipid peroxidation and cell necrosis in bromotrichloromethane hepatotoxicity in the perfused rat liver.

Bromotrichloromethane (CBrCl3)-induced hepatic lipid peroxidation and cell necrosis were studied histologically and biochemically, using isolated perfused livers from phenobarbital-pretreated rats. Lipid peroxidation was assessed by fuchsin staining of the liver slices and release of thiobarbituric acid reactive substances (TBARS) into the perfusate; necrosis was assessed by trypan blue uptake and lactate dehydrogenase (LDH) leakage. A good correlation was observed between the Schiff-positive reaction and TBARS release under various experimental conditions, supporting the validity of the fuchsin staining method for histological detection of lipid peroxidation. Lobular localization of lipid peroxidation and necrosis was as follows: Under high oxygen supply (95% O2-saturated buffer), infusion of CBrCl3 caused the Schiff-positive reaction in the pericentral to midzonal hepatocytes, irrespective of the direction of perfusion, but did not produce necrosis. Under low oxygen supply (20% O2) with retrograde perfusion, dissociation of lipid peroxidation and necrosis was observed, i.e., trypan blue uptake in the periportal zones and Schiff-positive staining in the pericentral hepatocytes. Thus, lipid peroxidation by itself may have a relatively minor role in the development of CBrCl3-induced acute hepatic cell death.

Animals↗

NZ-105, a new 1,4-dihydropyridine derivative: correlation between dihydropyridine receptor binding and inhibition of calcium uptake in rabbit aorta.

The correlation between the binding of NZ-105, a newly synthesized 1,4-dihydropyridine (DHP) derivative, on DHP receptors and its inhibitory activity on transmembrane 45Ca2+ uptake was investigated. 3H-NZ-105 bound rabbit aortic microsomes more slowly than did 3H-nitrendipine (3H-NTD): the association and dissociation rate constants of 3H-NZ-105 were about 70 times and 10 times less than those of 3H-NTD, respectively. The dissociation constant (Kd) of 3H-NZ-105 (4.48 nM) was about 6 times larger than that of 3H-NTD (0.79 nM), and the maximum number of binding sites (Bmax) for 3H-NZ-105 (112.5 fmoles/mg protein) was about the same as that for 3H-NTD (106.2 fmoles/mg protein). Unlabelled NZ-105 and nicardipine fully, and in a concentration-dependent manner, displaced 3H-NZ-105 specific binding. Pre-incubation with NZ-105 also concentration-dependently (more than 0.1 microM) inhibited the transmembrane 45Ca2+ uptake increment induced by a high-K+ (50 mM) solution. The inhibitory efficacy of NZ-105 became larger as the incubation period with this compound increased (from 1 hr incubation to 3 hr incubation), and recovery was difficult even after washout for 3 hr. Based on these results, we conclude that NZ-105 causes blockade of voltage-dependent calcium channels (VDCs) by binding to DHP receptors. Moreover, the very slow onset and recovery from NZ-105-induced vasodilation may be attributable to the slow and long-lasting inhibition of transmembrane calcium uptake, which accompanies its very slow binding to and dissociation from DHP receptors.

Animals↗

Microvascular architecture of rat nasal associated lymphoid tissue.

The blood vascular architecture of the rat nasal associated lymphoid tissue (NALT) was studied by scanning electron microscopy of corrosion casts. To examine the correlation of the vasculature with the distribution of lymphocyte subsets, the NALT was also studied by light microscopy of immuno-stained samples. The NALT was supplied by a branch of the inferior nasal artery which arose from the sphenopalatine artery. This branch reached the bottom of the NALT and ramified arterioles to the follicles and the parafollicular regions. These arterioles ascended toward the subepithelial region, giving off capillaries en route to form a coarse plexus within the follicles and the parafollicular regions. The arterioles reached the subepithelial region and formed a subepithelial capillary network consisting of a single layer of flat meshwork. The follicular, parafollicular and subepithelial capillaries anastomosed one another. The capillaries in each region were gathered into collecting venules, which in turn drained into high endothelial venules (HEVs) in the parafollicular region. The HEVs ran through the parafollicular regions around the follicular perimeters, and flowed into ordinary veins to leave the NALT. Lymphocytes labeled with an anti-T cell antibody were mainly distributed in the parafollicular regions, where HEVs were situated. B cells were mostly observed in the follicular and dome areas. The microvascular structure and its correlation with lymphocyte subset domains in the NALT were essentially similar to those in other mucosa associated lymphoid tissues (MALTs) such as tonsils and Peyer's patches.

Animals↗

[Microvascular architecture of the human tongue carcinoma--a scanning electron microscopic study].

Vascular architecture of tumors in experimental animals has been studied in detail. However, the reports on architecture of the capillaries in human carcinoma in the head and neck regions are few nowadays. In this paper architecture of the blood vessels reproduced by using methacrylate casting medium in human carcinoma of the tongue was studied by scanning electron microscopy. Tortous capillaries and loop-like vessels were observed at the proliferative area of the tumor on the surface of the tongue. There were avascular zones around the vessels of the tumor characterizing irregular proliferation. The vessels of sinusoidal, tapering, distorted and disrupted characters were seen in the muscle layer of the tongue. Ruptured vessels and viable tumor-cells were observed at the areas surrounding necrotic lesions. These findings elucidated combination of various kinds of architectures of vessels in various stages of tumor-growing. Existence of the avascular area suggests that proliferation of tumor-cells proceeds before proliferation of the capillaries. Both avascular and necrotic changes in the structure might reduce the effects of anti-cancer agents.

Capillaries↗

[Changes in respiratory, circulatory, endocrine, and metabolic systems under induced total spinal block].

Total spinal block was induced by 2% lidocaine in adult mongrel dogs, and its influence on the respiratory, circulatory, endocrine and metabolic systems was studied. HR, MAP, CI and LV dp/dt max during total spinal block decreased significantly compared with those during the control period. The blood gas, Qs/Qt and ETVI were hardly influenced by total spinal block. Regarding the endocrine and metabolic systems, plasma renin activity (PRA) was significantly elevated by total spinal block, while plasma epinephrine and norepinephrine levels showed no changes. Blood levels of lactic acid, pyruvic acid and blood sugar were not influenced by total spinal block.

Anesthesia, Spinal↗

[Two different types of monoclonal antibodies against gallbladder carcinoma cell line].

Monoclonal antibody FU-W-H6 whose immunoglobulin subclass was IgG2a kappa was produced against gallbladder carcinoma cell line FU-GBC-2. In normal tissue, this antibody has a strong reactivity specific to the mucosa of the gallbladder (14/15, 94%), bile duct (5/5, 100%), and pancreatic duct (4/5, 80%) in comparison with the lack of the gastric mucosa, and colorectal mucosa with statistically significant differences (p less than 0.01). In cancerous tissue, gallbladder cancer (11/12, 92%), bile duct cancer (5/5, 100%), and pancreatic cancer (2/2, 100%) reacted gastric cancer (4/12, 33%), and colorectal cancer (1/16, 6%) with statistically significant differences (p less than 0.05). On the other hand, another monoclonal antibody FU-W-E2 whose immunoglobulin was IgM has specificity to the gastrointestinal or gallbladder cancers. Eleven of 13 (85%) gastric cancers, 12 of 16 (75%) colorectal cancers, and 9 of 12 (75%) gallbladder cancers reacted positively with statistically significant differences with each normal epithelia (p less than 0.05). Immunoelectron microscopical study revealed that the antigen recognized by FU-W-H6 was localized by FU-W-H6 or E2 antigens were suggested to be a carbohydrates on the glycoprotein, and were thought to have relation to sialic acid by treatment of acid Sciff and enzymes. Western blot analysis demonstrated that their molecular weights were about 87000, and 92000.

Adenocarcinoma↗

[The evaluation of the modified Blalock-Taussig shunt with a prosthesis of microknitted Dacron for tetralogy of Fallot in early infancy].

We evaluated the surgical results of the modified Blalock-Taussig shunt (MBTS), performed with a prosthesis of microknitted Dacron, for the ductus-dependent tetralogy of Fallot (TOF) in early infancy. Nine MBTSs for eight patients, 4 with and 4 without pulmonary atresia, were performed, and one patient died. The mean age was 30 +/- 27 days, and the mean weight was 3460 +/- 770 g at the initial MBTS. In the initial two cases, the patients experienced convulsions due to severe hypoxia on account of the troubles of the preoperative administration of Prostaglandin E1 (PGE1). Thereafter, in order to prevent brain damage, we performed the MBTS following short-term administration of PGE1 (2-13 days). Consequently, we did not experience brain damage in later cases. Half of the patients with the MBTS with a 5 mm diameter prosthesis experienced postoperative congestive heart failure due to excessive pulmonary flow, and one of them died. The patients with the MBTS with a 4 mm diameter prosthesis had good postoperative courses. The suitable shunt flow in these patients was estimated to be 70-90 ml/kg/min. The MBTS with a 4 mm prosthesis obtained the lower level of this suitable shunt flow, but that a 5 mm prosthesis induced excessive shunt flow. Observing the patients' weight gain and the progress of polycythemia until two years of age, there were no differences between the MBTS with a 4 mm prosthesis and that with a 5 mm prosthesis. From these results, we recommend a 4 mm microknitted Dacron prosthesis for the MBTS of the TOF in early infancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗

[Clinical evaluation of intra-operative pelvic hyperthermochemotherapy combined with operation for rectal cancer].

In order to prevent local recurrence, intra-operative pelvic hyperthermochemotherapy (IOPHC) combined with surgery for rectal cancer has been performed. In this study, we evaluated the clinical effect of IOPHC in 20 patients who were given IOPHC, compared with 13 patients who underwent curative surgery without IOPHC (control group). The IOPHC procedure was as follows: After rectal amputation, the pelvic cavity was filled with a physiological saline containing 40 micrograms/ml of MMC. Then, the physiological saline was warmed and maintained by the apparatus (heater) we devised at 45 degrees C for 90 minutes. Local recurrence occurred in 2 cases of IOPHC group (2/20:10.0%), and in 3 cases in the control group (3/13:23.1%). On the other hand, distant metastases developed approximately at the same rate in the IOPHC group (4/20:20.0%) and control group (2/13:15.4%). Thus, IOPHC is a feasible approach to reduce local recurrence of rectal cancer.

Combined Modality Therapy↗

[Acute toxicity, inductive effects of liver enzymes and distribution in the liver of 1,2,3,7,8-pentachlorodibenzo-p-dioxin in rats].

Acute toxicity, inductive effects of liver enzymes and liver persistency of 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PenCDD) were compared with those of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) using male Wistar rats. 1,2,3,7,8-PenCDD treatment at a dose of 0.1 mumol/kg resulted in significant depression of growth of rats from a day to 28 days after treatment. However, the effect was relatively less than that of 2,3,7,8-TCDD. On 5 days, similarly to 2,3,7,8-TCDD-treated group, liver hypertrophy and thymic atrophy were observed in 1,2,3,7,8-PenCDD-treated groups. In addition, 1,2,3,7,8-PenCDD showed potent 3-methylcholanthrene-type inducing ability. For example, the activities of benzo(a)pyrene 3-hydroxylase and DT-diaphorase were 25-fold and 10-fold of control, respectively. On 30 days, about 50% of the inductive effects on 5 days were maintained in both 1,2,3,7,8-PenCDD- and 2,3,7,8-TCDD-treated groups. Amount of 1,2,3,7,8-PenCDD distributed to the liver on 5 days was about 80-90% of dose and was about 1.5 times greater than that of 2,3,7,8-TCDD. About 50% of dose of 1,2,3,7,8-PenCDD remained even on 30 days after treatment. From these results, it is suggested that 1,2,3,7,8-PenCDD possessing the potent acute toxicity comparable to 2,3,7,8-TCDD and higher persistency in the liver might be more important than 2,3,7,8-TCDD in terms of the chronic toxicity.

Animals↗

Effects of 3-methylsulphonyl-4,5,3',4'-tetrachlorobiphenyl and 7,8-benzoflavone on aryl hydrocarbon hydroxylase activity in Ah responsive and Ah nonresponsive strains of mice.

In general, C57BL/6NQdj (C57) and DBA/2JCrj (DBA) strains of mice are considered to be the aryl hydrocarbon (Ah) responsive and Ah nonresponsive strains of mice, respectively, which are determined by whether the hepatic aryl hydrocarbon hydroxylase (AHH) activity is enhanced (Ah responsive) or not (Ah nonresponsive) after the treatment of 3-methylcholanthrene (MC). In this study, first, we examined that the Ah responsiveness was systemically regulated in the lungs and kidneys as well as in the liver and observed its systemic control in these three organs in the two strains of mice. Then, we prepared the hepatic microsomes of the two strains of mice after the treatment of MC (42 mg/kg, once), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 20 micrograms/kg, 6 times) and 2,3,4,7,8-pentachlorodibenzofuran (PenCDF 60 micrograms/kg, 6 times) in order to investigate the effects of 3-methylsulphonyl-4,5,3',4'-tetrachlorobiphenyl (3-MSF-TCB, 1.5-45 micrograms/ml) and 7,8-benzoflavone (ANF, 1.4-42 micrograms/ml) on the respective hepatic microsomal AHH activities and the following results were obtained. 1. As compared with the control enzyme activity, TCDD-induced AHH activity was the highest, PenCDF-induced one the second and MC-induced the lowest in both strains of mice. The inductions of the enzyme activity by these chemicals were much more remarkable in the Ah responsive C57 strain than those in the Ah nonresponsive DBA strain. 2. 3-MSF-TCB and ANF enhanced or reduced the enzyme activity depending on both their concentrations and kinds of microsomes, namely, those prepared from untreated control mice and mice treated with MC, TCDD or PenCDF.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

[The effect of organochlorine compounds on the induction of sister chromatid exchanges in cultured human lymphocytes].

In this study, first, we investigated the effect of 7,8-benzoflavone (ANF), mitomycin C (MMC), a well-known genotoxic compound, and ANF plus MMC on the induction of sister chromatid exchanges (SCEs) in human whole-blood cultures. Second, we examined the effect of mixture of organochlorine compounds, which very resembled their contamination of healthy people in its composition, on the induction of SCEs in the same blood culture system in order to clarify their genotoxicity as a whole. The following results were obtained. 1. ANF and MMC significantly enhanced the number of SCEs/cell at the concentrations of 4 x 10(-5) M and 10(-8)M, respectively. When both of the compounds were simultaneously added in the blood cultures, their effects on the induction of SCEs seemed to be additive. 2. Without ANF in the blood culture system, namely, an usual system of the SCEs experiment, we could not find a dose-response relationship between the concentration of the mixture of organochlorine compounds and the induction of SCEs/cell. With ANF, however, we observed a fairly good dose-response relationship between them. 3. In the whole-blood culture system with ANF, we found significantly great number of SCEs/cell at the level of twenty times higher concentration of the organochlorine compounds than the ordinary level. According to the results described above and of our other studies, 50% effective concentration (EC50, about 2 SCEs/cell higher than control SCEs/cell) of the mixture was considered to be about 5 times greater level over the general one.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzofurans↗

[Elimination of PCDF and PCB congeners in the blood of patients with PCB poisoning in Taiwan].

The blood of 3 Yu-cheng patients sampled from 1980 to 1989 were analyzed for congeners of polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) by high resolution gas chromatography-mass spectrometry and gas chromatography-electron capture detection. The high concentrations of 2,3,4,7,8-penta-, 1,2,3,4,7,8-hexa- and 1,2,3,4,6,7,8-hepta-CDFs (15.4, 37.7 and 4.8 ppb in lipid basis, respectively) were eliminated from the blood at half-lives of 2.14, 2.56 and 2.32 years, respectively. The high concentrations of 8 PCB congeners in the blood were also decreased with time at half-lives of 1.16-4.56 years. The half-lives of retainable PCB congeners were about 2 times longer than those of the PCDF congeners.

Adult↗

[PCB methyl sulphone: comparison of tissue levels in Baltic grey seals and a Yusho patient].

Methyl sulphone metabolites of PCB and DDE were isolated from different tissues of a Baltic grey seal (Halichoerus grypus). Main components in the seal blubber were identified as 3-MeSO2-2,2',4',5,5'-pentaCB, 4-MeSO2-2,2',4',5,5'-pentaCB, 3-MeSO2-p,p'-DDE, 4-MeSO2-2,2',3',4',5-pentaCB and 4-MeSO2-2,2',3,4',5',6-hexaCB. Liver and lung in the seal contained different MeSO2-PCB pattern compared to all other tissues. These levels in the both tissues were estimated to be 28 and 15 ppm (lipid basis) which corresponded to the same level as the PCB. Concentrations of MeSO2-PCB in any tissues of a Yusho patient were low compared to those in the seal.

Animals↗

Sebaceous epithelioma in the external auditory meatus: a case report.

We report a rare case of sebaceous epithelioma(SE) in the external auditory meatus of an 84-year-old woman. The tumor, measuring 1.5 cm in diameter, was hemispherical, yellowish-brown, elastic and hard. It was removed surgically without complications and there has been no recurrence two years postoperatively. The histopathologic findings were characteristic of a sebaceous epithelioma. The controversy over the origin of this tumor is discussed.

Adenocarcinoma↗

Prognosis of patients with medically treated aortic dissections.

The purpose of this study is to evaluate the long-term results of medical treatment for a dissecting aorta and to detect the risk factors that determine the prognosis of medically treated patients. During the past 10 years, 228 patients with aortic dissections were admitted to our hospital and affiliated hospitals. One hundred thirty-four patients, including 60 with proximal type (Stanford, type A) and 74 with peripheral type (Stanford, type B) dissections, were treated by medical means alone. The survival rates of medically treated patients with type A dissections at 24 hours, 2 weeks, and 5 and 10 years after the onset of the disease were 72, 43, 34, and 28%, respectively, and the survival rates in type B dissections were 100, 92, 76, and 56%, respectively. The risk factors that determine poor prognosis in the acute phase of dissections were type A dissection and serious complications (rupture of the aorta, shock, cerebral accident, myocardial infarction, severe aortic regurgitation, renal failure, mesenteric infarction, and arterial occlusion in the extremities). The risk factors in the chronic phase were serious complications, excluding shock and rupture in the acute phase, the large diameter of the dissecting aorta, and increasing age. These results show that emergency surgical intervention is indicated in the patients with acute type A dissections and in those who had acute type B dissections with these serious complications. Medical treatment may be tentatively recommended for the patients with uncomplicated type B dissections until the operative death rate in these patients becomes less than presently identified.

Aortic Dissection↗