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Biomedical subjects

Y Murayama

Publications and source records attributed to Y Murayama.

At least 181 records · Page 10Linked to original sources
PubMed1993

[A case of papillary fibroelastoma of the heart found 13 years after open mitral commissurotomy].

A patient, 68-year-old female, underwent open mitral commissurotomy (OMC) for rheumatic mitral stenosis in April, 1979. In July of 1992, during the postoperative follow-up echocardiogram showed 8 x 7 mm mitral subvalvular tumor mass and mitral restenosis. Then, mitral valve replacement was performed using prosthetic valve (Carbomedics #25 mm). The tumor was located on the top of postero-medial papillary muscle and its chordae, and histologically was diagnosed as benign papillary fibroelastoma. Based on the findings of periodic echocardiogram, the tumor doubling time was estimated to be 283 days. The postoperative course was uncomplicated and she was discharged on the 34th post operative day. Papillary fibroelastoma is a rare benign cardiac tumor. Pathological origin of this tumor is still unknown. However, Lambl's excrescence, long-term inflammatory stimulation and/or thrombi are supposed to be etiologic factors. This tumor is generally found incidentally at the time of autopsy or operation because the patients are often asymptomatic. However, because the tumor causes embolism at times, periodic examination by echocardiogram after operation preserving valves is recommended, and surgical resection is required when the diagnosis is established.

Aged↗
PubMed1993

[Intraperitoneal administration of cis-diamminedichloroplatinum (II) for peritoneal carcinomatosis caused by gastric cancers].

The effectiveness of the intraperitoneal administration of cis-diamminedichloroplatinum (II) for peritoneal carcinomatosis by gastric cancers was evaluated through experimental and clinical studies. In experimental studies, the effect of sodium thiosulfate (STS) on cytotoxic activity of DDP was evaluated by MTT assay using human gastric cancer cell lines. The cytotoxic activity of DDP was reduced by 50% with 100-fold STS in the area under the curve (AUC), whereas 10-fold STS in AUC did not reduce the cytotoxicity of DDP. In clinical studies, patients were treated with one of three protocols: Group A was treated by the intraperitoneal injection (ip) of DDP at a dose of 70 mg/m2, and group B or C was treated by ip DDP at a dose of 110 mg/m2 with or without STS rescue. The pharmacodynamics and the adverse effects of treatments were evaluated between these three protocols. In group C, the means of AUC of STS were 2.43-, 10.8- and 86.8-fold those of total platinum in the peritoneal cavity, plasma, and urine, respectively. There were 1/5, 1/2 and 2/2 partial responses in peritoneal carcinomatosis patients treated with A, B and C. Renal toxicity was not observed in the patients treated with DDP and STS rescue. STS does not seem to reduce the antitumor activity of DDP in peritoneal cavity and plasma, while the renal cytotoxicity was reduced by STS rescue. The result led us to conclude that intraperitoneal DDP treatment combined with STS rescue would be useful chemotherapy against peritoneal carcinomatosis by gastric cancer.

Adult↗
PubMed1993

Effect of Ca2+ on the binding of Actinobacillus actinomycetemcomitans leukotoxin and the cytotoxicity to promyelocytic leukemia HL-60 cells.

The effects of Ca2+ on the binding of Actinobacillus actinomycetemcomitans leukotoxin (LT) to LT-susceptible promyelocytic leukemia HL-60 cells and the consequent cytotoxicity were investigated in comparison with those on LT-resistant erythroleukemia K-562 cells. The total amount of LT bound to the HL-60 and K-562 cells, as determined by ELISA using anti-LT rabbit serum, was essentially the same for both cells. The percentage of bound LT decreased in the presence of phosphatidylcholine (PC) was also almost equal for both cells. In contrast, EGTA added in the presence of PC enhanced the decrease of bound LT significantly from HL-60, but not from K-562. By monitoring the fluorescence of Fura-2 and of fluorescein as a measure for the change in intracellular calcium ions ([Ca2+]i) and cytotoxic activity, respectively, we showed that the exposure of HL-60 to LT induced the [Ca2+]i increase followed by the cell death, whereas this was distinctly not the case for K-562. These results indicate that a Ca(2+)-dependent LT-binding mechanism is possibly the step characteristic to LT-susceptible HL-60 cells.

Aggregatibacter actinomycetemcomitans↗
PubMed1992

Measurement of GTP gamma S binding to specific G proteins in membranes using G-protein antibodies.

We developed a novel method to quantitatively measure GTP gamma S binding to specific G proteins in crude membranes using G-protein antibodies. The basic strategy was that the materials were initially incubated with [35S]GTP gamma S at 37 degrees C. After 4 degrees C incubation in the wells of an ELISA plate precoated with G-protein antibodies, the radioactivity of each well was counted. This method, using an anti-Gi antiserum and an anti-Gs antiserum, quantitatively and specifically detected the binding of GTP gamma S to purified Gi2 and Gs. In S49 cell membranes, GTP gamma S binding to immunoreactive Gs was observed in a time-dependent manner that obeyed first-order kinetics, and the rate constant was stimulated approximately twofold in response to isoproterenol. The effect of isoproterenol was not observed in unc mutant membranes. The present method thus makes it possible to quantitatively measure GTP gamma S binding to specific G proteins in cell membranes.

Animals↗
PubMed1992

Comparison of the effects of nilvadipine and captopril on glucose and lipid metabolism in NIDDM patients with hypertension.

Changes of glucose and lipid metabolism in NIDDM hypertensive patients during treatment with a new dihydropyridine derivative, nilvadipine, were examined by a randomized, crossover study comparing the results with those elicited by captopril in 18 patients for 12 weeks each. Nilvadipine (8 mg per day) and captopril retard (75 mg per day) caused a sufficient decrease in blood pressure without changing the pulse rate. Nilvadipine and captopril did not significantly change fasting plasma glucose, hemoglobin A1c, serum cholesterol, triglycerides, high-density lipoprotein cholesterol or apoprotein A-I, A-II and B levels in either of the 12-week treatments. In 75-g oral glucose tolerance tests carried out three times in each patient (before treatment and after 12 weeks of treatment with each drug), changes in plasma glucose and serum insulin levels were not significantly different among the three tests. These results demonstrate that nilvadipine as well as captopril are antihypertensive drugs without adverse effects on glucose and lipid metabolism in hypertensive patients with NIDDM.

Analysis of Variance↗
PubMed1992

Effects of human recombinant epidermal growth factor on the growth of MKN-28 human gastric carcinoma transplanted into nude mice.

The effects of human recombinant epidermal growth factor (EGF) on the growth of MKN-28 human gastric carcinoma, transplanted into nude mice were studied. Modulation of tissue cAMP and EGF receptor levels by EGF was also studied to reveal the mechanism of the growth inhibitory effects of EGF. EGF exhibited a dose-dependent growth inhibitory effect on MKN-28 human gastric carcinoma transplanted into nude mice. Local injection of 2 ng of EGF moderately inhibited the growth of MKN-28 gastric carcinoma, while injections of 20 ng, 200 ng and 2 micrograms of EGF significantly inhibited tumour growth. EGF decreased tissue cAMP levels in a dose-dependent manner within 24 h after EGF injection. On the other hand, EGF increased the EGF receptor levels up to two or three fold within 24 h after EGF injection. Conversely, the EGF receptor affinity for EGF decreased according to the increase in EGF receptor levels.

Aged↗
PubMed1992

Interleukin-8 is a major neutrophil chemotactic factor derived from cultured human gingival fibroblasts stimulated with interleukin-1 beta or tumor necrosis factor alpha.

Inflammatory mediators produced by cells in the gingiva have been implicated in the initiation and progression of periodontal disease, a common infectious disease. In this study, we examined the biological activity of neutrophil chemotactic factors and the kinetics of expression of interleukin-8 (IL-8) mRNA derived from normal gingival fibroblasts in response to inflammatory mediators in an in vitro model. Gingival fibroblasts stimulated by either recombinant human interleukin-1 beta or recombinant human tumor necrosis factor alpha produced neutrophil chemotactic factors after 4 h, whereas expression of cell-derived IL-8 mRNA was detected within 1 h after stimulation. Furthermore, in a neutralization assay, rabbit anti-recombinant human IL-8 antiserum inhibited neutrophil chemotactic activity to basal levels. These results provide evidence that gingival fibroblasts synthesize potent chemotactic factors such as IL-8 in the presence of the inflammatory mediators interleukin-1 beta and tumor necrosis factor alpha. The activity of these factors may contribute to neutrophil-mediated processes in the pathogenesis of periodontal disease.

Cells, Cultured↗
PubMed1992

[A case of advanced breast cancer responding to low-dose 5'-DFUR].

A 69-year-old female patient with locally advanced breast cancer with multiple bone metastases (T4cN2-M1) was treated with 5'-DFUR after failure of tamoxifen treatment. The 5'-DFUR dose was limited to 600 mg per day, half the usual dose, because of its gastroenterological side effects. The primary tumor and metastatic axillary lymph nodes regressed three months after the start of treatment, and the complete remission of lesions was obtained in 16 months. Reduction of bone metastasis was confirmed by the disappearance of osteolytic lesion in the skull roentgenogram and the decrease of abnormal accumulation on the bone scintigram. Serum levels of CEA and ST-439 markedly reduced during the treatment as the disease regressed.

Aged↗
PubMed1992

[Targeting cancer chemotherapy using temperature-sensitive liposomes containing adriamycin conjugated with monoclonal antibodies].

Liposomes have a specific liquid-crystalline phase transition temperature (Tc), at which they release an entrapped drug. Temperature-sensitive liposomes containing adriamycin (TS-Lip-ADM) were made of dipalmitoylphosphatidylcholine (DPPC, Tc: 41 degrees C), distearoylphosphatidylcholine (DSPC, Tc: 54 degrees C), cholesterol and adriamycin. Monoclonal antibodies against human alpha-fetoprotein (AFP) were conjugated to TS-Lip-ADM. When liposomal suspension was immersed in a bath, the release rate of ADM from TS-Lip-ADM = Ab increased, as the temperature increased from 34 degrees C to 42 degrees C. ADM release was dependent on the temperature.

Antibodies, Monoclonal↗
PubMed1992

[Intra-arterial chemotherapy of local recurrence and non-curative case of colorectal cancer].

Twelve colorectal cancer patients, including 9 with local recurrent cancer and 3 with remnant cancer after surgery, were treated with intraarterial chemotherapy. Three cases were treated with MMC injection alone, 1 case with MMC combined with irradiation (MMC-R) and 8 cases with ADM combined with irradiation (ADM-R). In 7 evaluable patients, the response rate was 28.6% with 1 CR case, 1 PR case and 5 NC cases. The 2 cases treated with ADM-R were successful. Six of 8 patients treated with ADM-R survived more than 1 year, while all 4 patients treated with MMC or MMC-R died within 8 months. The cumulative survival rate after ADM-R treatment was 44% at 24 months. It is suggested that the combination of intra-arterial chemotherapy and radiation therapy is an effective treatment for local recurrence and non-curative cases of colorectal cancer.

Chemotherapy, Adjuvant↗
PubMed1992

[Spontaneous middle cerebral artery occlusion with moyamoya-like vessels associated with contralateral middle cerebral artery aneurysm; a case report].

A case of spontaneous middle cerebral artery occlusion with moyamoya-like vessels associated with contralateral middle cerebral artery aneurysm is reported. A 23-year-old male was admitted to our hospital with complaints of severe headache and vomiting. On admission CT scan demonstrated subarachnoid hemorrhage with high density in the left Sylvian fissure and suggested a ruptured left middle cerebral artery aneurysm. Carotid angiograms demonstrated a left middle cerebral artery aneurysm and an occlusion of the right middle cerebral artery at its origin with moyamoya-like vessels. There was no occlusion or stenosis in the bilateral intracranial internal carotid arteries. Furthermore, bilateral vertebral angiograms were also normal. The aneurysm was successfully clipped. The postoperative course was uneventful and the patient was discharged with no neurological deficit. So far as we could ascertain, there have been only 21 cases reported previously of spontaneous middle cerebral artery stenosis or occlusion with moyamoya-like vessels. According to angiographic studies and transcranial Doppler ultrasound findings, we are more inclined to believe that hemodynamic changes secondary to arterial occlusion lead to the formation and growth of aneurysms of the contralateral middle cerebral artery.

Adult↗
PubMed1991

Identification of a Gs activator region of the beta 2-adrenergic receptor that is autoregulated via protein kinase A-dependent phosphorylation.

We have localized a G protein activator region of the human beta 2-adrenergic receptor to region beta III-2 (from Arg259 to Lys273). The synthetic beta III-2, corresponding to the C-terminal end of the third cytoplasmic loop, activates Gs at nanomolar concentrations and weakly activates Gi. beta III-2 activates adenylyl cyclase at nanomolar concentrations in wild-type S49 lymphoma membranes, but not in membranes of unc mutant S49 cells, in which Gs is uncoupled from beta-adrenergic stimulation. Phosphorylation of beta III-2 by cAMP-dependent protein kinase A, which is involved in the desensitization of the beta-adrenergic receptor from Gs, drastically reduces the effect of beta III-2 on Gs while potentiating its action on Gi, resulting in a total loss of adenylyl cyclase-stimulating activity. These findings indicate that this receptor sequence is a multipotential G protein activator whose G protein specificity is regulated by protein kinase A.

Adenylyl Cyclases↗
PubMed1991

Monoclonal antibody to a specific antigen from Wolinella recta ATCC 33238.

Four monoclonal antibodies (m-Abs) to a specific antigen (150-kDa protein antigen) isolated from Wolinella recta ATCC 33238 by acid extraction were obtained. The four antibodies were all of the IgG1 subclass and exhibited equally high specificity for the antigen. A battery of 14 strains or oral bacteria were screened for cross-reactivity with each mAb by ELISA and Western blot analysis. Weak cross-reactivity to some strains was observed which differed depending upon the mAb. Immuno-electromicroscopic studies were performed with a mAb which revealed that the 150-kDa antigen was localized to the cell surface of W. recta ATCC 33238.

Animals↗
PubMed1991

Isolation and partial characterization of a 39 kDa major outer membrane protein of Actinobacillus actinomycetemcomitans Y4.

The outer membrane fractions of Actinobacillus actinomycetemcomitans, which were extracted from whole cells with cetyl trimethyl ammonium bromide and CaCl2, contained four major outer membrane proteins (MOMP) of 39, 37, 36 and 30 kDa. The 39 kDa MOMP of A. actinomycetemcomitans was sequentially purified by extraction with Zwittergent 3-14 detergent, anion-exchange chromatography and gel filtration chromatography. Analysis of amino acid composition and N-terminal amino acid sequence of 20 residues of purified 39 kDa MOMP was performed. Although some of the periodontitis patient sera reacted strongly with 39 kDa and 30 kDa MOMP in crude outer membrane fractions, purified 39 kDa MOMP showed decreased immunoreactivity with the human sera.

Actinobacillus↗
PubMed1991

Mechanical properties and immunogenicity of vascular xenografts.

Polyepoxy compounds (PC) have been introduced as new cross-linking agents to overcome some of the disadvantages of glutaraldehyde (GA). In this study, we investigated the relationship of the reaction time to the immunogenicity and mechanical properties of canine and bovine common carotid arteries cross-linked with one of PC, namely, glycerol polyglycidyl ether (GPE). To evaluate mechanical properties, we made use of the finite deformation theory. Arteries cross-linked with GPE for 48 hours proved to be about 3 times as flexible as those cross-linked with GA for 48 hours. In the immunogenicity experiments, GPE was observed to reduce the immunogenicity of the arteries according to the reaction time, and the arteries, which were cross-linked with GPE for 48 hours, showed little immunogenicity. It was concluded that GPE is a more suitable cross-linking agent than GA, and its optimum reaction time seems to be 48 hours.

Animals↗
PubMed1991

Comparison of beta-cell function after long-term treatment with either insulin, insulin plus gliclazide or gliclazide in neonatal streptozotocin-induced non-insulin-dependent diabetic rats.

There are no definite guidelines in the treatment of non-insulin-dependent diabetes mellitus (NIDDM) as to whether the treatment of choice is insulin, a sulfonylurea or a combination of insulin and sulfonylurea. We have therefore tried to evaluate the long-term effects of these treatments on beta-cell function in a rat model of NIDDM. NIDDM rats were prepared by the injection of streptozotocin (60 mg, i.p.) on the 5th day after birth. At 10 weeks, an oral glucose tolerance test (2 g/kg) was performed and rats were divided into 4 groups, each of which had the same mean glucose tolerance. The treatment of each group with either NPH insulin (4 U/kg/day), or oral gliclazide (10 mg/kg/day by a stomach cannula), or a combination of the above two, or a control (vehicle for gliclazide) was started from 12 weeks of age and continued for 6 months. Rats were fed ad libitum with standard rat chow. The weight gain of diabetic rats treated with gliclazide alone and of the vehicle-treated diabetic rats during 6 months was less than that of the other groups receiving insulin. The fasting plasma glucose of the insulin-only treated group stayed at the initial level for 6 months, but that of the other groups increased gradually. The frequency of deterioration of glucose tolerance for oral glucose loading (2 g/kg) in the insulin-only treated group was smaller than that in the other diabetic groups at 3 at 6 months after the start of treatment. The increase in plasma IRI after the oral glucose loading of the insulin-only treated group was the largest among the 4 groups at 6 months. In the pancreas perfusion experiment, the insulin response to glucose in the insulin-only treated group was more preserved than that in the other groups of diabetic rats after 6 months of treatment. These results suggest that treatment with insulin is effective in preserving beta-cell function in a rat model of NIDDM, whereas treatment with a sulfonylurea agent is not only ineffective but might negate the protective effect of insulin because the insulin-plus-gliclazide treated group elicited results similar to those of the gliclazide-only treated group except for the weight gain.

Animals↗