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Biomedical subjects

T Murano

Publications and source records attributed to T Murano.

At least 19 recordsLinked to original sources
PubMed2006

Hepatocyte growth factor secreted by cultured adipocytes promotes tube formation of vascular endothelial cells in vitro.

OBJECTIVE: Adipose tissue is closely associated with angiogenesis, but the mechanisms are not fully understood. Some of the adipocyte-derived cytokines are hypothesized to play an important role in angiogenesis. We evaluated tube formation of human umbilical vascular endothelial cells (HUVECs) cultured in type I collagen gel when overlaid with the supernatant of 3T3-L1 cell culture, and expression of tube-forming factor(s) in 3T3-L1 cells with or without pioglitazone. We also studied plasma growth factor levels in patients with type 2 diabetes mellitus treated with pioglitazone. RESULTS AND METHODS: The supernatant of 3T3-L1 cells increased tube formation of HUVECs by 9.03-fold of control. Reverse transcription-polymerase chain reaction showed that hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) mRNA were expressed in 3T3-L1 cells. Western blot analysis also demonstrated HGF and VEGF protein expression. When 3T3-L1 cells were treated with 100 nM small interfering RNAs (siRNAs) for HGF, the HGF mRNA and protein were suppressed. The VEGF mRNA and protein in the cells were also suppressed by siRNA for VEGF. The supernatant of 3T3-L1 cells treated with HGF siRNA suppressed tube formation of HUVECs by 61% compared with the supernatant of cells treated with control siRNA. Addition of VEGF siRNA resulted in no significant changes. The supernatant conditioned with pioglitazone further promoted the tube formation. Pioglitazone enhanced HGF mRNA expression in 3T3-L1 cells. After 12 weeks of pioglitazone treatment, the changes of plasma HGF levels in patients treated with pioglitazone were significantly higher than those in control. CONCLUSION: These results suggest that HGF secreted from 3T3-L1 cells may be the major factor regulating the tube formation, and agents that enhance the differentiation of adipocytes may promote tube formation of HUVECs mediated by HGF secreted by adipocytes.

3T3 Cells↗
PubMed2005

Clearance rates of cerivastatin metabolites in a patient with cerivastatin-induced rhabdomyolysis.

We report on a patient who developed acute rhabdomyolysis after taking cerivastatin. A 74-year-old hypercholestrerolaemic woman taking cerivastatin (0.15 mg/day) for 22 days complained of general muscle weakness and muscle pain. Her serum creatinine phosphokinase level was 19,190 IU/L. Serum myoglobin was over 3000 ng/mL. Serum concentration of cerivastatin at 6 h after taking the last dose (0.15 mg) was 8062.5 ng/L, which was almost 5.7 times higher than that of normal persons. The serum concentration of cerivastatin showed that the half-life of cerivastatin in this patient was 22.4 h, compared with 2.4 h for normal controls. Cerivastatin is catabolized by cytochrome P450, 3A4 and 2C8 to M-1, and by 2C8 to M-23. The ratio of M-23 to M-1 in her serum was much lower than that of control persons (0.64 vs. 2.08). She had previously taken simvastatin which is metabolized by CYP3A4, without any sign and symptoms of rhabdomyolysis. These results suggest that the slowed clearance of cerivastatin in this patient might have been compounded by cytochrome P450, 2C8 dysfunction.

Acute Disease↗
PubMed2003

Two cases with transient lipoprotein lipase (LPL) activity impairment: evidence for the possible involvement of an LPL inhibitor.

UNLABELLED: Two independent severe hypertriglyceridemic infants with transiently impaired lipoprotein lipase (LPL) activity were observed and the causes were explored. Both infants were female, born prematurely with low birth weight and developed hypertriglyceridemia (Fredrickson type V hyperlipidemia: high VLDL and low LDL/HDL) a few months after birth. While mass levels of their post-heparin plasma LPL and apoprotein C-II (apo C-II), a physiological activator of LPL, were normal, their post-heparin plasma LPL activities were remarkably impaired. Both of their mothers' post-heparin plasma LPL activities were slightly or moderately impaired as well, without a decrease in the LPL mass level. No mutations in the genes for LPL and apo C-II were detected in either patient. In an in vitro study with their serum at onset, we could not detect any distinct circulating inhibitors for LPL. There was no data supporting infection or autoimmune diseases, which might have an impact on LPL activity, during the follow-up period. Levels of their plasma triglyceride (TG) and total cholesterol (TC) were decreased quickly by a dietary intervention with medium-chain triglyceride (MCT) milk and kept normal even after stopping the intervention at around age 1 year. However, their low post-heparin LPL activity persisted and returned to normal at around age 2 years. Their low HDL cholesterol levels persisted even after recovery of the TG and TC levels, although lecithin:cholesterol acyltransferase (LCAT) and cholesterol-ester-transfer protein (CETP), two key enzymes of HDL metabolism, were normal throughout the course. The exact reasons why their post-heparin LPL activities were impaired for a certain period and why their HDL cholesterol levels have remained low are still unclear. CONCLUSION: Transiently impaired LPL activity with no defect in LPL enzyme induced severe hypertriglyceridemia in infants. The transient occurrence of inhibitor(s) for LPL was proposed.

Child↗
PubMed2001

Presence of aldose reductase inhibitors in tea leaves.

Water extract from commercial English tea has a potent inhibitory activity against human placenta aldose reductase (NADPH oxidoreductase, E.C.1.1.1.21.). Inhibitory activity was separated into five major fractions by one-step chromatography with a C-18 reverse phase column. The most active fraction was further subjected to reverse phase column chromatography. As a result, a well-known flavone-glycoside, isoquercitrin, was isolated as the most potent chemical. The inhibitory character of isoquercitrin for aldose reductase was a mix of uncompetitive and noncompetitive inhibitions, and its IC50 was 1 x 10(-6) M. In rat sciatic nerve tissue preparations, sorbitol accumulation in the presence of high concentrations of glucose (30 mM) was inhibited by 38% at 5 x 10(-4) M of isoquercitrin. The flavone-glycoside isoquercitrin is the active inhibitor of aldose reductase inhibitor present in English tea. Given the ability of aldose reductase inhibitors to prevent diabetic complications, an epidemiological study of the effect of tea consumption on the pathogenesis and progression of diabetic complications would be interesting.

Aldehyde Reductase↗
PubMed2000

Enhancement of preheparin serum lipoprotein lipase mass by bezafibrate administration.

To clarify the clinical implication of preheparin serum lipoprotein lipase mass (preheparin LpL mass), we studied the relationships between preheparin LpL mass and serum lipids, including midband lipoproteins, which migrate between very low density lipoproteins and low density lipoproteins on polyacrylamide gel disc electrophoresis, in hyperlipidemias. And we also studied the changes of preheparin LpL mass in hypertriglyceridemic patients during bezafibrate administration, which is known to enhance LpL activity in postheparin plasma. Preheparin LpL mass correlated positively with high-density lipoprotein-cholesterol (HDL-C) (r=0.418, P<0.01) and negatively with triglyceride (TG) (r=-0.256, P<0.01), but did not correlate with total cholesterol (TC) in 64 hyperlipidemic (type IIa, IIb and IV) patients. The midband lipoproteins were observed in 80% of hypertriglyceridemic patients (32/40). Preheparin LpL mass in midband lipoprotein-positive subjects was lower significantly than that in midband-negative subjects. When bezafibrate (400 mg/day) was administrated to 40 hypertriglyceridemic patients for 4 months, TG level significantly decreased (-49+/-7%, P<0.01), TC levels decreased (-11+/-4%, not significant), and HDL-C levels increased (+27+/-4%, P<0.01). The midband lipoproteins disappeared in 95% of patients. Preheparin LpL mass significantly increased (+25+/-6%, P<0. 0005). In nine patients who stopped bezafibrate, TG levels significantly increased (+49+/-7%, P<0.01) and HDL-C levels decreased (-27+/-4%, P<0.01). Preheparin LPL mass significantly decreased (-25+/-6%, P<0.0005). These results suggested that bezafibrate administration enhanced preheparin LpL mass. And it might be implicated that enhanced LpL production by bezafibrate could reflect an increase of preheparin LpL mass.

Bezafibrate↗
PubMed1999

Synthesis and biological evaluation of alpha,alpha-difluorobenzylphosphonic acid derivatives as small molecular inhibitors of protein-tyrosine phosphatase 1B.

A series of alpha,alpha-difluorobenzylphosphonic acids having a hydrophobic functional group were prepared via the Stille coupling reaction from halogenated alpha,alpha-difluorobenzylphosphonates. Evaluation of inhibitory activity toward protein tyrosine phosphatase (PTP 1B) revealed that the ethynyl, phenylethynyl and (E)-styryl groups on the benzene nuclei increased the inhibitory activity of alpha,alpha-difluorobenzylphosphonic acid. Inhibitory activities significantly increased upon introducing both (E)-styryl and bis-methylsulfonamide functional groups onto the benzene nuclei of alpha,alpha-difluorobenzylphosphonic acid.

Enzyme Inhibitors↗
PubMed1999

Preheparin serum lipoprotein lipase mass level: the effects of age, gender, and types of hyperlipidemias.

To clarify the factors regulating preheparin serum lipoprotein lipase mass (preheparin LPL mass), the correlations between preheparin LPL mass and age, gender and types of hyperlipidemias were investigated in 377 persons who underwent annual health examinations. Preheparin LPL mass level did not significantly differ in individuals from 19 to 70 years old, for both men and women. Preheparin LPL mass level correlated negatively with triglyceride (TG), positively with high density lipoprotein-cholesterol (HDL-C), and not at all with total cholesterol (TC) or low density lipoprotein-cholesterol (LDL-C). Preheparin LPL mass levels were apparently higher in women than in men, but when serum lipid levels were adjusted, preheparin LPL mass levels were identical. In type IV and IIb hyperlipidemia, preheparin LPL mass levels were lower than in type IIa patients and in normals. Remnant positive individuals had lower levels of preheparin LPL mass than the negative individuals. In conclusion, preheparin LPL mass levels were not affected by aging and gender, but were lower in the conditions in which TG catabolism was disturbed, indicating that preheparin LPL mass might reflect somewhat the amount of LPL working in the body.

Adult↗
PubMed1999

The effect of insulin sensitizer, troglitazone, on lipoprotein lipase mass in preheparin serum.

Lipoprotein lipase mass exists in preheparin serum, even though the activity is scarcely found. The implication of this is unclear. We studied the effect of an insulin sensitizer, troglitazone, on this preheparin serum lipoprotein lipase mass (preheparin LPL mass) in non-insulin-dependent diabetes mellitus (NIDDM) patients as well as on serum lipid levels and low density lipoproteins (LDL) particle size. Thirty-one NIDDM patients with poor control were administered troglitazone 400 mg/day. Hemoglobin A1c had significantly decreased (13%, P < 0.001) 2 months later. Preheparin LPL mass had gradually increased and a 69% increase (P<0.01) was observed 4 months later. Triglyceride significantly decreased (23%, P < 0.01) and high density lipoprotein-cholesterol increased (10%, P < 0.01), whereas total cholesterol and LDL levels did not change 4 months later. The size of LDL increased significantly (P < 0.01). These results were consistent with the idea that preheparin LPL mass might be relating to the insulin sensitivity enhanced by troglitazone, as well as LDL particle size.

Adult↗
PubMed1998

Genomic organization and mapping of the human activin receptor type IIB (hActR-IIB) gene.

Activins, members of a family of proteins that includes transforming growth factor-beta (TGF-beta), are gonadal polypeptide hormones that stimulate secretion of follicle-stimulating hormone (FSH). During large-scale sequencing analysis of a 1.2-Mb fragment of human genomic DNA on 3p22-p21.3, we found the gene encoding activin receptor type IIB (hActR-IIB). Comparison of its reported cDNA sequence with this genomic sequence showed that the hActR-IIB gene consists of 11 exons and spans about 30 kb of genomic DNA.

Activin Receptors, Type II↗
PubMed1998

[New approach from lipoprotein disorders to atherosclerosis].

To make diagnosis arteriosclerosis directly by biochemical markers is not easy, but to identify risk factors by biochemical markers is useful. Lipoprotein disorder is one such risk factor. Low density lipoproteins (LDL), remnants and small LDL were high risks of coronary disease in Japanese. Moreover, those incidences were significantly higher in diabetes mellitus, especially with nephropathy, and latter two lipoproteins frequently coexisted. Oxidizability of small LDL was the highest among LDLs, indicating that small LDL promotes atherosclerosis by forming oxidized lipids, which enhance complicated lesion of atherosclerosis. The mechanism by which the remnant is retained remains unknown. We measured LPL mass in preheparin serum. Preheparin LPL mass was negatively correlated with triglyceride, and positively correlated with high density lipoprotein cholesterol. Further more, preheparin LPL mass was lower in remnant-positive persons, indicating that preheparin LPL mass might be involved in remnant clearance. Understanding the role and catabolism of LPL itself requires further study.

Arteriosclerosis↗
PubMed1998

[The examination of apoE phenotypes in diabetic patients with peripheral neuropathy].

Apolipoprotein E (apoE), which is reported to recognize the low density lipoprotein receptor and remnant receptor, mediates the delivery of cholesterol and other lipids to the cells all over the body. There are several phenotypes such as apoE2, apoE3 and apoE4. Recently, it is reported that apoE plays an important role in neurite outgrowth. To determine whether apoE phenotype is concerned in diabetic peripheral neuropathy, we investigated the incidence of apoE phenotypes in diabetic patients with peripheral neuropathy. The occurrence of retinopathy and nephropathy were not different in apoE2, apoE3 and apoE4. However, the frequency of diabetic neuropathy was higher in apoE4 than apoE2 and apoE3 (p < 0.05). Furthermore, as the stage of diabetic neuropathy advanced, the incidence of apoE4 increased. From these results we conclude that apoE phenotype influences the progress of diabetic peripheral neuropathy and that apoE4 contributes to the deterioration of diabetic peripheral neuropathy.

Aged↗
PubMed1997

Cytotoxicity of some oxysterols on human vascular smooth muscle cells was mediated by apoptosis.

A decrease in smooth muscle cells is observed in advanced atherosclerotic lesion. To understand this mechanism, we selected oxysterols as candidates for toxic lipid, and examined their cytotoxicity on human cultured vascular smooth muscle cells, together with the manner of cell death. In the presence of 7-ketocholesterol or 7 beta-hydroxycholesterol (50 mumol/L), the percentage of detached cells increased significantly with dose dependency, and an increase in detached cell number and DNA nick detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling study (TUNEL) preceded an increase in lactate dehydrogenase released into the medium. DNA extracted from smooth muscle cells incubated with 7-ketocholesterol or 7 beta-hydroxycholesterol showed a laddering pattern on agarose electrophoresis. In the presence of 7-ketocholesterol or 7 beta-hydroxycholesterol, fragmented DNA quantified by the quantitative sandwich enzyme immunoassay was significantly increased. From these results, it is proposed that 7-ketocholesterol and 7 beta-hydroxycholesterol are toxic to smooth muscle cells, and that this cytotoxicity is mediated by apoptosis.

Apoptosis↗
PubMed1991

Heme peptide as a model substance for halogenomethane activation and heme modification.

Octa-heme peptide (CHP) obtained from Candida krusei cytochrome c was tested for suicidal activation of halogenomethanes. Under anaerobic conditions, CHP was kept in the reduced state in the presence of NADPH and NADPH-cytochrome P-450 reductase. Addition of CBrCl3 to the reduced CHP caused spectral changes such as rapid disappearance of alpha and beta bands and gradual decrease in the gamma-peak height, accompanied by oxidation of NADPH. Heme content of the reaction mixture, determined as pyridine hemochrome, also decreased NADPH dependently. CCl4 was less effective than CBrCl3, while CHCl3 had almost no effect. N-tert-butyl-alpha-phenylnitrone (PBN) suppressed the CBrCl3-induced heme damage, and resulted in the formation of radical adduct .PBN-CCl3 as evidenced by ESR spectroscopy. Radical formation was also observed with CCl4. The CHP damage induced by CBrCl3 was also accompanied by the release of Br- about 11-12-times molar excess of CHP, whereas the release of CHCl3 was about 20% that of Br-.FD-MS assay of the product of CHP reaction suggested that 10 trichloromethyl radicals bonded with CHP. Thus, CBrCl3 undergoes single-electron reduction in the presence of reduced CHP to trichloromethyl radicals, which covalently bind to CHP molecules. Heme peptide may be a useful tool in the study of mechanisms involved in the destruction of cytochrome P-450 by halogenomethanes.

Amino Acid Sequence↗
PubMed1989

Development of precipitating antibody in chickens experimentally infested with northern fowl mite, Ornithonyssus sylviarum (Acari: Macronyssidae).

In order to examine the immune response of chickens to different population levels of mites, a microscopic slide modification of the Ouchterlony double-gel diffusion technique was adopted for examination of circulating antibody against the extract of northern fowl mite, Ornithonyssus sylviarum. Precipitating antibodies were detected in all the chickens infested with the mite. One to three clearly defined precipitation lines appeared in almost all the serum samples of infested birds. Titers of antibody correlated with population levels of the mite on chickens, and no differences in antibody development of hens and roosters were distinguished. These results suggest that the titration of precipitating antibodies appears to be useful for the assessment of mite population levels on chickens.

Animals↗
PubMed1980

Comparative studies on the hepatotoxic actions of chloroform and related halogenomethanes in normal and phenobarbital-pretreated animals.

Hepatotoxic action of CHCl3 was examined biochemically by comparing with those of CCl4 and other related halogenomethanes using normal and phenobarbital (PB)-pretreated animals. In the later stage (24 hr), in mice, PB pretreatment augmented CHCl3-induced liver damage as evidenced by an enhancement of elevation of plasma transaminase activities and a parallel rise in liver triglyceride content. In the earlier stage (1 hr), in normal rats, CCl4 (1.0 ml/kg, i.p.) decreased microsomal glucose-6-phosphatase (G-6-Pase) activity and cytochrome P-450 content, whereas no significant effect was observed with the same dose of CHCl3. PB pretreatment produced a significant loss of both enzymes by CHCl3, and enhanced the loss of cytochrome P-450 induced by CCl4, while G-6-Pase activity was little affected by CCl4 in PB-pretreated rats. Both hepatotoxins increased liver malondialdehyde (MDA) content. Some of these early changes in vivo were reproduced in the lipid peroxidation system in vitro. Diethyldithiocarbamate suppressed various toxic manifestations induced by CHCl3 in PB-pretreated rats, but did not protect against the loss of cytochrome P-450 induced by CHCl3 or CCl4. These results suggest that lipid peroxidation hypothesis proposed for CCl4 hepatotoxicity may be applied to the case of CHCl3 though there exist some qualitatively different characteristics between these hepatotoxins, and that the mechanisms of the loss of microsomal G-6-Pase and cytochrome P-450 by either of these hepatotoxins might be different.

Animals↗
PubMed1979

Effect of linoleic acid hydroperoxide on liver microsomal enzymes in vitro.

Rat liver microsomes incubated with linoleic acid hydroperoxide (LAHPO) lost cytochrome P-450 specifically among the enzymes of microsomal electron transport systems. The loss of cytochrome P-450 content and glucose-6-phosphatase activity by LAHPO was accompanied by an increase in malondialdehyde (MDA) production. Turbidity of microsomal suspensions was decreased with increasing MDA production, but not proportionately. Diethyldithiocarbamate (DTC), N,N'-diphenyl-p-phenylenediamine and alpha-tocopherol inhibited almost completely the LAHPO-induced MDA production of microsomes, however no perfect protection against the loss of cytochrome P-450 content and glucose-6-phosphatase activity was observed. The decrease of microsomal turbidity by LAHPO was little affected in the presence of DTC. Purified cytochrome P-450 was destroyed by LAHPO, with minimal protection by the compounds described above. These results suggest the possibility that the loss of microsomal enzyme activities during lipid peroxidation may be attributed largely to a direct attack on enzyme proteins by lipid peroxides rather than indirectly to a structural damage of microsomal membranes resulting from peroxidative breakdown of membrane lipids.

Animals↗