Biomedical subjects

F Hashimoto

Publications and source records attributed to F Hashimoto.

At least 19 recordsLinked to original sources

PubMed1995

Effect of gemfibrozil on lipid biosynthesis from acetyl-CoA derived from peroxisomal beta-oxidation.

The effect of gemfibrozil, a peroxisome proliferator, on lipid biosynthesis from acetyl-CoA derived from peroxisomal beta-oxidation was studied. The specific activity of the peroxisomal fatty acyl-CoA beta-oxidation system of rats fed a chow containing 0.2% gemfibrozil for 2 weeks was approximately five times higher than that of control rats. When [1-14C]lignoceric acid, a very-long-chain fatty acid which is degraded exclusively by the peroxisomal beta-oxidation system at first, was injected into rats treated with gemfibrozil, radioactivity and content of bile acid in the bile were enhanced to approximately 2.2 and 3.5 times the control, respectively. Gemfibrozil increased the radioactivity and content of chenodeoxycholic acid more than that of cholic acid. The incorporation of radioactivity into cholesterol in the bile was as much as 4.5 times greater than the control, and content was 2.6 times greater. In the liver, incorporation of [14C]lignoceric acid into the simple lipids phosphatidylethanolamine and phosphatidylcholine was unaffected by gemfibrozil. The radioactivity and content of cholesterol separated from the simple lipids were also virtually unaffected. However, the specific activities of 3-hydroxy-3-methylglutararyl-CoA reductase (rate-limiting enzyme of cholesterol synthesis) of peroxisomes and microsomes were remarkably stimulated by gemfibrozil treatment. These results suggest that biosyntheses of cholesterol and bile acid from acetyl-CoA derived from peroxisomal beta-oxidation are stimulated by gemfibrozil, due at least in part to activation of the peroxisomal beta-oxidation system and 3-hydroxy-3-methylglutaryl-CoA reductase of peroxisomes and/or microsomes. Most peroxisomal proliferators (e.g. clofibrate) have been known to inhibit 3-hydroxy-3-methylglutaryl-CoA reductase activity. Therefore, gemfibrozil is expected to be a very useful tool for elucidating the relationship between peroxisomes and the biosyntheses of cholesterol and bile acid.

Animals↗

PubMed1995

Heart rate and respiratory rhythm dynamics on ascent to high altitude.

OBJECTIVE: To investigate the alterations in autonomic control of heart rate at high altitude and to test the hypothesis that hypoxaemic stress during exposure to high altitude induces non-linear, periodic heart rate oscillations, similar to those seen in heart failure and the sleep apnoea syndrome. SUBJECTS: 11 healthy subjects aged 24-64. MAIN OUTCOME MEASURES: 24 hour ambulatory electrocardiogram records obtained at baseline (1524 m) and at 4700 m. Simultaneous heart rate and respiratory dynamics during 2.5 hours of sleep by fast Fourier transform analysis of beat to beat heart rate and of an electrocardiographically derived respiration signal. RESULTS: All subjects had resting hypoxaemia at high altitude, with an average oxyhaemoglobin saturation of 81% (5%). There was no significant change in mean heart rate, but low frequency (0.01-0.05 Hz) spectral power was increased (P < 0.01) at high altitude. Time series analysis showed a complex range of non-linear sinus rhythm dynamics. Striking low frequency (0.04-0.06 Hz) heart rate oscillations were observed during sleep in eight subjects at high altitude. Analysis of the electrocardiographically derived respiration signal indicated that these heart rate oscillations correlated with low frequency respiratory oscillations. CONCLUSIONS: These data suggest (a) that increased low frequency power during high altitude exposure is not simply attributable to increased sympathetic modulation of heart rate, but relates to distinctive cardiopulmonary oscillations at approximately 0.05 Hz and (b) that the emergence of periodic heart rate oscillations at high altitude is consistent with an unstable cardiopulmonary control system that may develop on acute exposure to hypoxaemic stress.

Adult↗

PubMed1994

Focal segmental glomerular sclerosis, a type of intractable chronic glomerulonephritis, is a stem cell disorder.

The etiopathogenesis of focal and segmental glomerular sclerosis (FGS) remains unknown. Using a new animal model for FGS (FGS mouse), we demonstrate here that bone marrow transplantation from normal mice to FGS mice with a high grade of proteinuria (+ + +) ameliorates FGS, and that the transplantation of bone marrow cells or purified hemopoietic stem cells (HSCs) from FGS mice induces FGS in normal mice. These findings strongly suggest that FGS is a stem cell disorder; the abnormalities may be genetically programmed at the level of HSCs.

Animals↗

PubMed1994

Fate of allogeneic or syngeneic cells in intravenous or portal vein injection: possible explanation for the mechanism of tolerance induction by portal vein injection.

In this report we examine the fate of donor cells injected via different routes. When PKH-26-labeled C57BL/6 (B6) spleen cells were intravenously (i.v.) injected into BALB/c mice, the donor cells were rejected within 3 days. In contrast, when the same B6 spleen cells were portal venously (p.v.) injected, they were trapped in the recipient liver. When allogeneic or syngeneic whole bone marrow cells (BMC) or cells in a hemopoietic stem cell (HSC)-enriched fraction were either i.v. or p.v. injected, the cells accumulated in the liver. The cells trapped in the liver were found to be wheat germ agglutinin (WGA)-positive HSC. When B6 thymocytes were p.v. or i.v. injected into BALB/c mice, they were rapidly rejected. When BALB/c mice were i.v. preimmunized with unlabeled B6 spleen cells, BMC or thymocytes, the p.v. or i.v. injected PKH-26-labeled B6 spleen cells were rejected rapidly (within 2 days). In contrast, when BALB/c mice were p.v. preimmunized with B6 spleen cells or BMC, the p.v. or i.v. injected PKH-26-labeled B6 spleen cells were not rejected. The cells responsible for the tolerance induction were found to be HSC trapped in the liver. Delayed-type hypersensitivity assays revealed that the tolerance could be maintained for more than 49 days by p.v. injection plus i.v. injection (at intervals of 2 weeks) of HSC. These findings indicate that HSC trapped in the liver play a crucial role in the induction and maintenance of p.v. tolerance.

Animals↗

PubMed1992

Long-term follow-up of vascularized bone grafts for the reconstruction of tibial nonunion: evaluation with computed tomographic scanning.

Ten cases of reconstruction of the tibia with vascularized bone grafts were evaluated by computed tomographic (CT) scanning. In all cases the grafts were placed because of pseudarthrosis. The patients ranged in age from 20 to 64 years. The duration of follow-up was 1-9 years. In six cases fibular grafts were used to bridge the defect and in four cases iliac crest grafts were used. No additional bone grafts were placed after the initial operation. The pseudarthroses were classified into three types: type N--no bony defect (4 cases); type P--partial bony defect (3 cases); and type C--complete segmental bone loss (3 cases). Our evaluation showed that the grafts used to treat the type N and type P pseudarthroses were the same shape and size as at the time of placement. The grafts used to treat the type C pseudarthroses were hypertrophied, although the medullary canal of the graft remained the same size as at the time of placement. Hypertrophy was a result of an extraperiosteal reaction. The fibular grafts were square rather than triangular in cross section. It was concluded that mechanical loading is important in promoting hypertrophy of the graft.

Adult↗

PubMed1992

Effects of aminotriazole treatment on biosyntheses of primary bile acids in vivo.

The influence of aminotriazole treatment on primary bile acid biosynthesis was studied in detail. After administration of aminotriazole to rats, bile was collected for 8 h. The content of chenodeoxycholic acid in the bile was increased to 144% of the control by aminotriazole treatment, but that of cholic acid was decreased to 48.4%. In another experiment, [4-14C]cholesterol was injected into rats immediately after aminotriazole treatment, and then bile was collected. The content of radioactive chenodeoxycholic acid in the bile was significantly increased to 130% of the control, but that of radioactive cholic acid was unchanged. In a similar experiment with [2-14C]mevalonate, the content of radioactive chenodeoxycholic acid in the bile was hardly changed by aminotriazole treatment, but that of radioactive cholic acid was greatly decreased to 41.2% of the control. Aminotriazole treatment did not affect the ratios of tauroconjugate to glycoconjugate of the two bile acids. Thus, aminotriazole treatment affects the syntheses of not only cholesterol (F. Hashimoto, C. Sugimoto and H. Hayashi, Chem. Pharm. Bull., 38, 2532 (1990); F. Hashimoto and H. Hayashi, Biochim. Biophys. Acta, 1086, 115 (1991)) but also primary bile acids in vivo. Namely, aminotriazole treatment activated biosynthesis of chenodeoxycholic acid from exogenous cholesterol, but did not affect that of cholic acid. Aminotriazole hardly affected the synthesis of chenodeoxycholic acid through endogenous cholesterol (from mevalonate), but inhibited that of cholic acid.

Amitrole↗

PubMed1992

Determination of absorption and endogenous excretion of iron in man by monitoring fecal excretion of a stable iron isotope (58Fe).

The absorption and endogenous excretion of iron in man was studied by monitoring the fecal excretion of a stable iron isotope (58Fe). The study was carried out for 12 healthy volunteers who were divided into two groups. Group I received 58Fe-labeled ferric ammonium citrate (III) (58FeAC) equivalent to 6 mg of iron as a control, and group II received a combination of 500 mg of vitamin C and 58FeAC. A new formula was used to calculate the 58Fe absorption ratio reflecting the pool of iron in the intestinal cells, and the ratio was compared with that obtained from Janghorbani's formula, which has been used as one of the common methods. As a result, the 58Fe absorption ratio in group II was statistically significantly higher than that of group I (34.4 +/- 6.1% vs. 15.0 +/- 5.5%, M +/- SD) using Janghorbani's formula. The similar absorption ratio (34.1 +/- 6.0% vs. 14.8 +/- 5.5%) was also obtained by our new formula. Our results confirmed the previous findings that the availability of iron is stimulated by the supplementation of vitamin C. Both formulae agreed in the absorption of iron, indicating that the endogenous excretion of iron (caused by the desquamated cells) in the intestine does not disguise the iron absorption.

Absorption↗

PubMed1992

[Cricoarytenoid joint involvement in rheumatoid arthritis].

The cricoarytenoid (CA) joint, which controls the vocal cords, is diarthrodial; it is composed of two cartilages with a ligamentous capsule lined by synovial membrane. It has been known that inflammation of CA joint occurs sometimes in patients with rheumatoid arthritis (RA). Yet, so far, no detailed full-report on this subject has ever been made in this country. Here we report four RA cases with CA joint ankylosis or abduction disturbance due to progression of CA arthritis. Episodes of inspiratory dyspnea were observed in all cases and tracheostomy was performed in case 1 and case 2. Further surgical intervention i.e., tracheoplasty was necessary in case 2. Case 3 and case 4 have been followed conservatively thus far. Clinical surgical interventions were necessitated mainly with joint replacement, 3) there exists severe destruction of cervical spines as well as temporomandibular joints. Rheumatologist must be fully aware of how urgent this clinical entity is and not miss-diagnose+ these patients.

Arthritis, Rheumatoid↗

PubMed1991

Identification of intermediates after inhibition of cholesterol synthesis by aminotriazole treatment in vivo.

Cholesterol synthesis from mevalonate is inhibited by aminotriazole treatment in vivo. We tried to identify intermediates accumulated in liver of aminotriazole-treated rats. At 6 h after the aminotriazole treatment, the liver was excised. Sterols were extracted from it, and subjected to capillary gas-liquid chromatography, high-performance liquid chromatography, gas-liquid chromatography linked to mass spectrometry and gas-liquid chromatography linked to Fourier-transform infrared spectrometry. It was found that 4 alpha-methyl-5 alpha-cholest-7-en-3 beta-ol and 4,4-dimethyl-5 alpha-cholest- 8-en-3 beta-ol were accumulated in the liver, mainly as the free forms. The contents of the former and the latter were increased to 25- and 64-times the control values, respectively. In another experiment, [2-13C]mevalonate was injected at 2 h after aminotriazole treatment, and 4 h later the liver was excised. The sterols extracted from the liver were subjected to gas-liquid chromatography linked to mass spectrometry. Specific fragment ions reflecting the incorporation of [13C] mevalonate were detected in the mass spectra of the intermediate sterols. Accumulation of 4 alpha-methyl-5 alpha-cholest-7-en-3 beta-ol and 4,4-dimethyl-5 alpha-cholest-8-en-3 beta-ol after aminotriazole treatment suggests that elimination of the 4 alpha-methyl group from 4-methyl intermediate sterols is inhibited by aminotriazole.

Amitrole↗

PubMed1991

Improvement in iron deficiency anemia through therapy with ferric ammonium citrate and vitamin C and the effects of aerobic exercise.

In 781 female college students, there were 41 cases of iron deficiency anemia, 209 of latent iron deficiency, 3 of other anemias, and 528 normal cases. Fifty-four volunteers recruited from the iron deficiency anemia and severe latent iron deficiency groups were randomly divided into 4 study groups. Groups I and III received 500 mg of vitamin C daily, and groups II and IV received ferric ammonium citrate (FeAC; equivalent to 6 mg iron) in addition to vitamin C for 9 weeks. Groups I and II were loaded by aerobic exercise at 50% VO2 max. Significant differences between groups were noted in serum ferritin (SF) in III/IV, hematocrit (Ht) in II/III and III/IV, and reticulocytes (RET) in I/II, I/IV, and III/IV. Hemoglobin (Hb) and other iron-related blood indices tended to normalize in groups II and IV when compared with the pre-values. VO2 max was elevated in groups I and II regardless of iron treatment, but was augmented more in group II than group I.

Adolescent↗

PubMed1991

Changes in orientation of the major interlobar fissure in chronic liver diseases.

The orientation of the major interlobar fissure, as an indicator of right lobar atrophy, was evaluated using axial MR imaging in 64 patients with histologically proven chronic liver diseases. The "interlobar fissure angle" was determined by a line drawn through the middle hepatic vein and inferior vena cava and a horizontal line at the level of hepatic hilus. The angle was significantly smaller in cirrhosis than in either chronic persistent or active hepatitis. A much smaller angle was observed in cirrhosis associated with colonic interposition. The increasing incidence of small "interlobar fissure angle" (less than 30 degrees) was observed to parallel the histological stages from chronic persistent hepatitis to liver cirrhosis. All the cirrhotic patients with colonic interposition and an angle of less than 30 degrees. This simple method is considered useful in the diagnosis of right lobar atrophy and disease severity in chronic liver disease.

Adult↗

PubMed1990

Digital replantation in children: a long-term follow-up study.

This paper reports a series of 14 cases of digital replantation in children who had had a total of 17 digits traumatically amputated. All but two digits survived, for an overall success rate of 88%. The length of follow-up was between 3 and 14 years (average 8 years). Sensory recovery of all digits was satisfactory. The mean growth rate of replanted digits relative to contralateral digits was 86%. Twelve cases had an excellent result, and one case had a good result. Digital replantation in children is recommended when feasible.

Amputation, Traumatic↗

PubMed1990

Significance of catalase in peroxisomal fatty acyl-CoA beta-oxidation: NADH oxidation by acetoacetyl-CoA and H2O2.

To clarify the significance of catalase in peroxisomes, we have examined the effect of aminotriazole treatment of rats on the activity of beta-hydroxybutyryl-CoA dehydrogenase in liver peroxisomes. When the effect of H2O2 on the dehydrogenase activity was examined using an extract of liver peroxisomes from aminotriazole-treated rats, the acetoacetyl-CoA-dependent oxidation of NADH was found to increase considerably on the addition of dilute H2O2. Such an effect of H2O2 was not seen on the beta-hydroxybutyryl-CoA-dependent reduction of NAD nor with extracts from untreated animals. We then noticed that similar NADH oxidation was caused non-enzymatically by a mixture of acetoacetyl-CoA and H2O2. The oxidation was dependent on both acetoacetyl-CoA and H2O2, and was blocked by scavengers of oxyradicals such as ascorbate and ethanol. Degradation products formed during the reaction of acetoacetyl-CoA with H2O2 had no NADH oxidizing activity, indicating that effective oxidant(s) were generated during the reaction of H2O2 with acetoacetyl-CoA. No other fatty acyl-CoA so far examined nor acetoacetate could replace acetoacetyl-CoA in this reaction. Therefore, if H2O2 were to be accumulated in peroxisomes, it would decrease both NADH and acetoacetyl-CoA, thus affecting the fatty acyl-CoA beta-oxidation system. These results, together with our previous finding that peroxisomal thiolase was significantly inactivated by H2O2 [Hashimoto, F. & Hayashi, H. (1987) Biochim. Biophys. Acta 921, 142-150] suggest that the role of catalase in peroxisomes is at least in part to protect the fatty acyl-CoA beta-oxidation system from the deleterious action of H2O2.

3-Hydroxyacyl CoA Dehydrogenases↗

PubMed1990

Inhibition of cholesterol synthesis from mevalonate by aminotriazole treatment in vivo.

3-Amino-1,2,4-triazole (aminotriazole) is an irreversible inhibitor of catalase which is a marker enzyme of peroxisomes. We studied the effect of aminotriazole treatment on biosyntheses of cholesterol and bile acid in vivo. When catalase activity of peroxisomes of rat liver was inhibited by aminotriazole treatment, bile acid content in the bile was significantly decreased to about 70% of the control, but that in the liver was not changed. Cholesterol content in the bile was significantly decreased to about 80% of the control, while in liver and serum the content was not significantly changed. When [2-14C]mevalonate was administered to rats, radioactivities of cholesterol in the liver, serum and bile were all drastically decreased by aminotriazole treatment, and an unidentified radioactive product was detected. Radioactivity of bile acid in the bile was also greatly decreased. In a similar experiment with [4-14C]cholesterol, aminotriazole treatment had no effect on the radioactivity of either cholesterol or bile acid in the liver, serum and bile. In this case, the unidentified product could not be detected. These results indicate that when catalase activity of liver peroxisomes is suppressed by aminotriazole treatment, biosynthesis of bile acid from exogenous cholesterol is not inhibited, but a step in the pathway of biosynthesis of endogenous cholesterol from mevalonate is inhibited.

Amitrole↗

PubMed1989

Changes in polyamine-oxidizing capacity of peroxisomes under various physiological conditions in rats.

Rat liver peroxisomal polyamine oxidase activity was determined under various physiological conditions by using the peroxidase method with phenol and 4-aminoantipyrine. N1-Acetylpolyamines such as N1-acetylspermine and N1-acetylspermidine were better substrates than the free polyamines. The polyamine oxidase activity in rat peroxisomes increased significantly when cell proliferation was high. The activity began to appear in fetal liver at the 16th approximately 18th day of pregnancy and peaked in neonatal liver on the first day (approx. 1.7-times higher than in adult liver). In regenerating rat liver, only polyamine oxidase activity among the peroxisomal enzymes tested was increased considerably 12 h after partial hepatectomy (approx. 2.8-fold over the control liver). Finally, the enzyme activity was significantly increased by administration of clofibrate, a peroxisome proliferator, which also causes hepatomegaly. In all cases, the increase in polyamine oxidase activity was not more than 3-fold. Since the level of polyamine oxidase activity in the normal liver is more than adequate in relation to the level of the substrates, the slight but significant increase under conditions of cell proliferation may have a role in modulating levels of polyamines in the proliferating liver tissue.

Animals↗

PubMed1989

Radioimmunoassay of glycated serum protein using monoclonal antibody to glucitollysine and coomassie-brilliant-blue-coated polystyrene beads.

A radioimmunoassay for glycated serum protein (GSP) was developed using monoclonal antibody to glucitollysine and polystyrene beads coated with Coomassie-Brilliant-Blue (CBB) as adsorbent for serum protein. The monoclonal antibody was raised by immunizing BALB/c mice with reduced glycated LDL and fusing their spleen cells with mouse myeloma cells. CBB-coated polystyrene beads were introduced to absorb a constant amount of serum protein. The protein adsorbed on the CBB-coated beads was reduced by NaHB4, and after treatment with radiolabeled antibody, the radioactivity of each bead was counted with an automatic gamma-counter. The standard glycated protein used was reduced glycated human serum albumin, in which 8 of 59 lysine residues were glycated. The intra- and interassay coefficients of variation of GSP were 4.8-6.5% and 1.6-6.0%, respectively. The GSP level of diabetic patients was significantly higher than that of normal controls (1.97 +/- 1.23 vs. 0.47 +/- 0.21 nmol/mg-protein; mean +/- SD, p less than 0.001). The GSP levels of patients with insulin-dependent and non-insulin-dependent diabetes mellitus were 3.03 +/- 1.05 and 1.51 +/- 1.00 nmol/mg-protein, respectively. A good correlation was found between the levels of GSP and hemoglobin A1c (HbA1c) (r = 0.85, p less than 0.001). In patients admitted to the hospital for diabetes education and glycemic control, the GSP level decreased 43 +/- 12% with the decrease in the fasting plasma glucose level (39 +/- 13%) and the mean daily plasma glucose level (MPG, 47 +/- 15%) in a four week period after admission, whereas the HbA1c level decreased only 13 +/- 6% during this period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Specific radioimmunoassay of glucitol-lysine--application to lens proteins in streptozotocin-diabetic rats.

A radioimmunoassay using antibody against glucitol-lysine was developed to quantitate glycated proteins in the lens of diabetic rats. The amount of glycated protein was expressed as molar equivalents of reduced glycated hippuryl lysine (GlcRED-Hip-Lysine). Significant differences (p less than 0.01) were found in the amounts of glycated protein in the lenses of rats with streptozotocin-induced diabetes (3.92 +/- 0.59 nmol/mg protein, n = 5), those with streptozotocin-induced diabetes treated with insulin (2.94 +/- 0.36 nmol/mg protein, n = 4) and normal rats (1.23 +/- 0.22 nmol/mg protein, n = 5). There was a significant correlation between the concentration of glycated protein in the lens and the HbA1c level at the end of the 12 week experiment (r = 0.957, p less than 0.001). These results indicate that glycation of lens protein is parallel with the severity of diabetes in rats.

Animals↗

PubMed1988

Time-dependent changes of collagen crosslinks in the socket after tooth extraction in rabbits.

Time-dependent changes of the reducible collagen crosslinks in the healing tissue of rabbit tooth extraction wounds were analyzed chromatographically. The ratio of dihydroxylysinonorleucine to hydroxylysinonorleucine in the collagen from normal alveolar bone was 4.4. This value increased about four times, on the 10th day after tooth extraction, coinciding with the phase of active woven bone formation, and then decreased rapidly toward a normal value on the 14th day after tooth extraction. The data suggest that active biosynthesis and fibrillogenesis of bone collagen precede the morphological completion of lamellar bone formation.

Alveolar Process↗