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M Chiba

Publications and source records attributed to M Chiba.

At least 235 records · Page 13Linked to original sources
PubMed1993

Effect of protein binding on 4-methylumbelliferyl sulfate desulfation kinetics in perfused rat liver.

4-Methylumbelliferyl sulfate (4MUS), a polar metabolite of 4-methylumbelliferone (4MU), is known to undergo desulfation and participate in futile cycling with 4MU. Unusual parabolic or increasing profiles of the steady-state extraction ratio (Ess) of 4MUS with respect to concentration in rat livers perfused with a red cell (20%)-albumin (1%) medium have been reported (Ratna et al., 1993). In order to study this unusual phenomenon, we examined the desulfation of 4MUS in the single-pass rat liver in the absence of albumin. We further employed a tubular-flow model to describe the present observations and data previously obtained on 4MUS in order to predict the effects of protein binding and enzymatic constants for conjugation/deconjugation on the hepatic processing of 4MUS and its metabolites. The net hepatic extraction ratio from albumin-free perfusate decreased from 0.465 to 0.326 when the 4MUS input concentration was increased from 122 to 908 microM; moreover, the unusual profiles previously observed for ESS with increasing concentration in albumin-containing perfusate were not apparent. The hepatic clearances and desulfation rates of 4MUS were essentially identical to those observed in the presence of albumin, when the latter were expressed in terms of unbound concentrations (unbound input and logarithmic average unbound concentration of the input and output blood). Initial modeling indicated that first nonlinear protein binding (dissociation constant KD of 93 microM) and then saturable desulfation (Km of 382 microM) were responsible for the unusual increasing and then decreasing trend of ESS with concentration in the presence of albumin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[An experimental study on the correction of scoliotic deformity--an application of the short segmental fixation system].

The purpose of this experimental study is to seek a possibility if we could apply a short segmental fixation system for the correction of spinal deformity and keeping the moveability of the spine. We used 40 scoliotic rabbits in the experiment which were made after the Piggot's procedure. Apex of the curvature could be observed around T8 or T9. Ten of 40 rabbits were observed as a control group. On the other hand, the remaining 30 were used for an instrumentation group utilizing the short segmental fixation. Two complexes of T10-T11 and T12-L1 were made by mamillary process fixatives, bilateral small rods, wires and bone cement. The final magnitude of Cobb angle was 46.8 degrees on the average in the control group, and 14.8 degrees in the instrumentation group. In conclusion, short segmental fixation around the caudal area of the apex of the scoliotic curvature plays a major role in the correction of spinal deformity.

Animals↗
PubMed1993

Futile cycling between 4-methylumbelliferone and its conjugates in perfused rat liver.

Futile cycling between 4-methylumbelliferone and its sulfate and glucuronide conjugates was examined in the single-pass perfused rat liver preparation. The steady-state hepatic extraction ratio of 4-methylumbelliferone was found to be high (0.97) at a low input concentration of 0.005 mumol/L (tracer), with a net 4-methylumbelliferyl sulfate/4-methylumbelliferyl glucuronide ratio of about 5:1; at 63 mumol/L the steady-state extraction ratio had remained constant despite a shift from net sulfation to net glucuronidation. At higher input 4-methylumbelliferone concentrations, saturation was evidenced by a decreased steady-state extraction ratio and reduced net sulfation and net glucuronidation. Because 4-methylumbelliferyl sulfate and 4-methylumbelliferyl glucuronide deconjugation would result in an intracellular accumulation of 4-methylumbelliferone, the phenomenon was monitored with a shift in tracer [3H]4-methylumbelliferone metabolism from sulfation to glucuronidation with increased intracellular 4-methylumbelliferone concentration. When 4-methylumbelliferyl sulfate (0 to 890 mumol/L) or 4-methylumbelliferyl glucuronide (0 to 460 mumol/L) was delivered simultaneously with tracer [3H]4-methylumbelliferone to the rat liver, notable desulfation of 4-methylumbelliferyl sulfate (18% to 38% rate in) but little deglucuronidation of 4-methylumbelliferyl glucuronide (1.2% to 2.1% rate in) was observed. With 4-methylumbelliferyl sulfate, 4-methylumbelliferone and 4-methylumbelliferyl glucuronide were readily found as metabolites, whereas with 4-methylumbelliferyl glucuronide, levels of the metabolites, 4-methylumbelliferone and 4-methylumbelliferyl sulfate, were much reduced. 4-Methylumbelliferyl sulfate and not 4-methylumbelliferyl glucuronide shifted tracer [3H]4-methylumbelliferone metabolism from [3H]4-methylumbelliferyl sulfate to [3H]4-methylumbelliferyl glucuronide formation in a concentration-dependent fashion. The steady-state extraction ratio for 4-methylumbelliferyl sulfate (0.1 to 0.3) was comparatively higher than that for 4-methylumbelliferyl glucuronide (0.05), and it was found to increase with concentration, an observation explained by the nonlinear protein binding of 4-methylumbelliferyl sulfate. Biliary excretion rates for 4-methylumbelliferone and 4-methylumbelliferyl sulfate were proportional to their input or net formation rates, regardless of whether 4-methylumbelliferone, 4-methylumbelliferyl glucuronide or 4-methylumbelliferyl sulfate was administered. By contrast, the excretion rate of 4-methylumbelliferyl glucuronide when administered was only 1/25 the excretion of 4-methylumbelliferyl glucuronide formed from 4-methylumbelliferone and 4-methylumbelliferyl sulfate. The extent of choleresis paralleled the excretion patterns of preformed and formed 4-methylumbelliferyl glucuronide; bile flow was normal with 4-methylumbelliferyl glucuronide administration and was markedly enhanced with increased 4-methylumbelliferone or 4-methylumbelliferyl sulfate administration. The data suggest the presence of a transmembrane barrier for entry of 4-methylumbelliferyl glucuronide and not 4-methylumbelliferyl sulfate or 4-methylumbelliferone into hepatocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

IgG subclass-containing cells around the lymph follicle in the human intestine.

The authors previously reported the ring-like distribution of IgG-containing cells around the lymph follicle in both the small and large intestine. In the present study, the distribution of IgG subclass-containing cells around the lymph follicle was examined in both the small and large intestine, including Peyer's patches, by the indirect immunoperoxidase staining method. A ring-like distribution of IgG subclass-containing cells was observed in 14 out of 21 lymph follicles including 4 Peyer's patches (66.7%) in the terminal ileum, and 4 out of 7 (57.1%) in the large intestine. The percentages of IgG1-, IgG2-, IgG3-, and IgG4- containing cells around the lymph follicle in the terminal ileum were 27.6 +/- 11.6%, 51.9 +/- 15.4%, 16.5 +/- 10.2%, and 4.0 +/- 3.1%, respectively, and those in the large intestine were 22.9 +/- 15.4%, 47.4 +/- 14.9%, 11.2 +/- 4.1%, and 18.5 +/- 7.7%, respectively. Thus, among the IgG subclasses, IgG2-containing cells showed the most frequent ring-like distribution around the lymph follicle. The IgG2 predominance around the lymph follicle in the intestine was markedly different from reported IgG1 predominance in the lamina propria in the large intestine. This difference in IgG subclass distribution may suggest different origins of the IgG subclass-containing cells in the lamina propria and in areas around the lymph follicle.

Adolescent↗
PubMed1992

Expression of MHC class II antigens (HLA-DR, -DP, and -DQ) on human gastric epithelium.

Class II antigen expression on gastric epithelium was investigated using an immunoperoxidase method in relation to the degree of inflammatory cell infiltration in the lamina propria. Sixty-six biopsy specimens from 43 patients with chronic gastritis were examined. The frequency of HLA-DR expression in specimens with cell infiltration was 94%, while that in specimens without cell infiltration was 24%. There was significant difference in the frequency of HLA-DR expression between the two groups (P less than 0.01). HLA-DR was most intensely expressed in the glandular neck portion. The frequency and extent of class II antigen expression on gastric epithelium with cell infiltration were in the following order: DR greater than DP greater than DQ. The extent of DR and DP, but not DQ expression generally paralleled the degree of cell infiltration. Intestinal metaplasia was found in 13 specimens. In the area of intestinal metaplasia, epithelial class II staining was absent except for one specimen. These results suggest that the respective genes of three class II antigens are regulated by different mechanisms and that an immunological mechanism plays a role in the pathogenesis of gastritis.

Epithelium↗
PubMed1992

Studies on antimutagenic effect of milk cultured with lactic acid bacteria on the Trp-P2-induced mutagenicity to TA98 strain of Salmonella typhimurium.

The inhibitory effects of cultured milk using 76 strains of lactic acid bacteria isolated from milk products were investigated on the mutagenicity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P2), a tryptophan pyrolysate for Salmonella typhimurium TA98. Each cultured milk sample displayed its characteristic antimutagenic effect against the mutagenicity of Trp-P2. The milk cultured with Lactobacillus acidophilus LA106 (LA2) showed the highest inhibition of 82.1% among the strains used. Milk samples cultured with Lactococcus lactis subsp. lactis, Lll103 (10-3) and Lll102 (KM) also exhibited higher inhibition percentages.

Animals↗
PubMed1992

Inhibition of erythrocyte 5-aminolaevulinate hydrolase activity by tin and its prevention by selenite.

Mice were injected with either SnCl2 (intraperitoneal) or Na2SeO3 (subcutaneous) alone or together at doses of 50 mumol/kg body weight. After 20 hours blood was collected and the concentrations of tin (Sn) and Selenium (Se) and the activity of 5-aminolaevulinate hydrolyase (ALA dehydratase, EC 4.2.1.24) in blood were determined. The concentrations of Sn in whole blood were 4.9 (SD 1.5) nmol/ml (n = 4) and ALA dehydratase activity was 10% of the control in Sn treated animals. Concentrations of Sn were 2.6 (SD 0.6) nmol/ml and ALA dehydratase activity was 92% of that in control animals when Sn and Se were simultaneously injected. The supernatant from lysed erythrocytes from Sn treated mice were applied to a Sephacryl S-300 column. The predominant peak containing Sn was eluted at the position of haemoglobin; a second peak was eluted at the position of ALA dehydratase. When the supernatant of lysed erythrocytes from mice injected with Sn and Se was chromatographed, a negligible amount of Sn was detected in the ALA dehydratase fraction. It thus appears that Sn binds to ALA dehydratase molecules and inhibits enzyme activity, and that simultaneous injection of Se prevents Sn binding to ALA dehydratase, thereby preventing the inhibition of ALA dehydratase activity by Sn.

Animals↗
PubMed1992

The effect of orthodontic retention on the mechanical properties of the periodontal ligament in the rat maxillary first molar.

The load-deformation curves obtained by extraction of the rat maxillary first molar from its socket in the dissected jaw were analyzed so that the effect of orthodontic retention on the mechanical properties of the periodontal ligament could be examined. An elastic band was inserted between the rat maxillary first and second molars for four days, and then the interdental space was filled with resin for four or eight days. The average interdental spaces between the teeth ranged from 315 to 398 microns during the experimental period. The maximum shear load, elastic stiffness, and failure energy in shear decreased markedly following application of an orthodontic force, but they increased gradually and reached control levels on the 8th day after the retention. Maximum shear deformation at maximum load was not significantly different between the experimental and control teeth during the experimental period. It is suggested that, following orthodontic tooth movement, occlusal function was restored after a relatively short retention period, as was the impaired mechanical strength of the periodontal ligament.

Alveolar Process↗
PubMed1992

Plasma atrial natriuretic factor in patients with acute myocardial infarction.

To examine whether atrial natriuretic factor (ANF) is secreted adequately in the early phase of myocardial infarction, plasma ANF concentration and clinical parameters, including hemodynamic variables, were studied in 118 patients with acute myocardial infarction (AMI). The patients were divided into 2 subgroups according to the absence (group A, n = 41) or presence (group B, n = 77) of a history of valvular heart disease, previous myocardial infarction, hypertension, or renal failure. Although no significant difference in atrial pressure after the infarction was found between the 2 groups, the plasma ANF level was significantly lower in group A than in group B (76 +/- 6 vs. 185 +/- 26 pg/ml; mean +/- SEM, p < 0.01). Plasma ANF was correlated with pulmonary capillary wedge pressure in group B (r = 0.54, p < 0.001), whereas no relationship with hemodynamic parameters was observed in group A. In 56 of the 118 patients (group A, n = 18; group B, n = 38), the pulmonary arterial plasma level was significantly higher in group A (p < 0.05), whereas the difference was not significant in group B. Seven of the 8 expired cases among these 56 patients had peripheral plasma ANF levels of more than 150 pg/ml, which were higher than those in pulmonary arterial plasma. These observations suggest firstly that the plasma level of ANF is lower in patients with a new onset of myocardial infarction compared to those with a history of cardiac or renal diseases, and secondly that stimulated ANF release originates not only from the right side of the heart, but also from additional site(s), particularly in patients with chronic ventricle overload and a poor prognosis.

Atrial Function, Right↗
PubMed1992

[Determination of protoporphyrins in blood using HPLC. Standardization of protoporphyrins and interlaboratory comparison of analyses].

1) In order to compare the results of determination of protoporphyrin IX (PP) and zinc protoporphyrin IX (ZP) using HPLC, the preparation procedures for standard solutions of PP and ZP were studied at four laboratories. According to the methods mutually agreeable to the four laboratories, the absorption values using UV-Vis spectrometer from the 4 laboratories were found to be identical. 2) The total of 28 whole blood samples obtained from the same workers whose Pb-B levels ranged from 2.9 to 87.9 micrograms/dl were sent to the 4 laboratories for determination of PP and ZP. The laboratories were allowed to use their own HPLC apparatus, column, mobile phase and fluorometric detectors, although the same procedures were used to prepare the standard solutions of PP and ZP. The results showed that significant biases in ZP and PP levels were found between two out of the 4 laboratories, but the ZP values corrected by the recovery rate showed no statistical difference among the laboratories. 3) Blood levels of ZP, total protoporphyrin (TP, calculated by PP+ZP/1.1), and PP determined by HPLC method correlated well with free erythrocyte protoporphyrin (FEP) determined by the method of extraction into the acidic solvent. The correlation coefficients between Pb-B and log TP, ZP, FEP or PP were 0.82-0.84, 0.80-0.83, 0.786, or 0.70-0.73, respectively. 4) The coincident ratios of PP/TP obtained at 4 laboratories ranged from 12.1 to 19.0%. These values were within a relatively narrow range, although two different kinds of organic solvents (DMF: N',N'-dimethylformamide or Methanol/triton-X 100) were used in the extraction steps.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMed1992

Brain tumor in a pedigree of cancer family syndrome.

Brain tumors have not been previously described as a cancer found in cancer family syndrome (Lynch Syndrome II). Astrocytoma found in the 24-year-old son of a proband of cancer family syndrome with an unusual aggregation of transitional cell cancer is reported. The possibility of brain tumors as a rare spectrum of neoplasms in cancer family syndrome is discussed.

Adult↗
PubMed1992

Crohn's disease associated with diffuse lymphoid hyperplasia of the large intestine: a possible role of the lymph follicle in HLA-DR antigen expression on epithelium.

A 14-year-old girl diagnosed as Crohn's disease had lymphoid hyperplasia throughout the large bowel. Biopsy specimens from the lymphoid hyperplasia demonstrated non-caseous granulomas within the lymph follicles. An immuno-histochemical study of biopsy specimens showed that HLA-DR antigens were expressed on epithelium close to the lymph follicle, which was observed in all specimens containing the lymph follicle. This case provides evidence for the importance of the lymph follicle in the etiopathogenesis of Crohn's disease by demonstration of non-caseous granulomas within the lymph follicle and expression of HLA-DR antigens on epithelium close to the lymph follicle.

Adolescent↗
PubMed1992

Antimutagenicity of milk cultured with lactic acid bacteria against N-methyl-N'-nitro-N-nitrosoguanidine.

The antimutagenic effect of cultured milk using 71 strains of lactic acid bacteria belonging to the genus Lactobacillus, Streptococcus, Lactococcus, and Bifidobacterium on the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine was investigated in vitro using Salmonella typhimurium TA 100 as an indicator bacterium. Each cultured milk sample displayed its characteristic antimutagenic effect on the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine. The milk cultured with Lactobacillus acidophilus LA 106 (LA2) showed the highest inhibition of 77% against the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine among the strains tested. Changes in the antimutagenic effect of the milk cultured by Lb. acidophilus LA 106 (LA2) during incubation were also examined using N-methyl-N'-nitro-N-nitrosoguanidine as a mutagen.

Animals↗
PubMed1992

[A case of gastric carcinoma with peritonitis carcinomatosa responding remarkably to etoposide, adriamycin and cisplatin (EAP) therapy].

The patient was a 62-year-old male who had Borrmann 4 type gastric cancer. He presented massive ascites due to peritonitis carcinomatosa and the cytology of ascites was class V. He was treated with 3 courses of EAP (etoposide, adriamycin, cisplatin) therapy. Computed tomography showed ascites nearly disappeared. Remarkable improvement was observed by barium meal study and endoscopic examination, and partial remission (PR) was achieved. As for toxicity bone marrow suppression, alopecia and elevation of BUN were observed.

Adenocarcinoma↗
PubMed1992

[Histochemical study of adrenergic nerve fibers in the skeletal muscle of the rat].

The distribution of adrenergic nerve fibers in the vessels, nerves, and skeletal muscles of the rat was studied by the glyoxylic acid fluorescence method and by electron microscopy. The changes in catecholamine fluorescence were investigated after decentralization, lumbar sympathectomy, and femoral nerve ligation. Catecholamine fluorescence was mainly localized in the arteries, and arterioles in the perimysium of the skeletal muscle. Sometimes, a spot-shaped catecholamine was seen in the metarteriole and capillary. Adrenergic nerve fibers ran parallel with femoral nerve fibers. After lumbar sympathectomy catecholamine fluorescence disappeared, the fluorescence in the quadriceps femoris muscle did not disappear even after ligation of the femoral nerve. Unmyelinated nerve fibers were identified adjacent to the capillary, whereas adrenergic nerve fibers were seen approaching to the quadriceps femoris muscle within a gap of 300 nm.

Adrenergic Fibers↗
PubMed1992

Toxic and trace elements in tobacco and tobacco smoke.

While the harmful health effects of carbon monoxide, nicotine, tar, irritants and other noxious gases that are present in tobacco smoke are well known, those due to heavy metals and other toxic mineral elements in tobacco smoke are not sufficiently emphasized. Tobacco smoking influences the concentrations of several elements in some organs. This review summarizes the known effects of some trace elements and other biochemically important elements (Al, As, Cd, Cr, Cu, Pb, Mn, Hg, Ni, Po-210, Se, and Zn) which are linked with smoking. Cigarette smoking may be a substantial source of intake of these hazardous elements not only to the smoker but also, through passive smoking, to nonsmokers. The adverse health effects of these toxic elements on the fetus through maternal smoking, and on infants through parental smoking, are of special concern.

Evaluation Studies as Topic↗