Search PubMed⌕ Search

Biomedical subjects

M Chiba

Publications and source records attributed to M Chiba.

At least 109 records · Page 6Linked to original sources
PubMed1998

Isotope dilution analysis of Se in human blood serum by using high-power nitrogen microwave-induced plasma mass spectrometry coupled with a hydride generation technique.

To establish a method for sensitive, accurate, and precise determination of Se in real samples, isotope dilution analysis using high-power nitrogen microwave-induced plasma mass spectrometry (N2 MIP-IDMS) was conducted. In this study, freeze-dried human blood serum (Standard Reference Material, NIES No. 4) provided by NIES (National Institute for Environmental Studies) was used as a real sample. The measured isotopes of Se were 78Se and 80Se which are the major isotopes of Se. The appropriate amount of a Se spike solution was theoretically calculated by using an error multiplication factor (F) and was confirmed experimentally for the isotope dilution analysis. The mass discrimination effect was corrected for by using a standard Se solution for the measurement of Se isotope ratios in the spiked sample. However, the sensitivity for the detection of Se was not so good and the precision of the determination was not improved (2-3%) by N2 MIP-IDMS with use of the conventional nebulizer. Therefore, a hydride generation system was connected to N2 MIP-IDMS as a sample introduction system (HG-N2 MIP-IDMS) in order to establish a more sensitive detection and a more precise determination of Se. A detection limit (3 sigma) of 10 pg mL-1 could be achieved, and the RSD was less than 1% at the concentration level of 5.0-10.0 ng mL-1 by HG-N2 MIP-IDMS. The analytical results were found to be in a good agreement with those obtained by the standard addition method using conventional Ar ICPMS.

Freeze Drying↗
PubMed1998

Comparison of biomechanical properties of the incisor periodontal ligament among different species.

BACKGROUND: The aim of this study was to obtain a more precise understanding of the mechanical properties of the periodontal ligament in continuously erupting incisors by comparing the shear stress-strain relations among teeth from four closely related species. METHODS: Four species of experimental animals (mice, hamsters, rats, and rabbits) were used. Transverse sections of the left mandibular incisors were cut from the incisal, middle, and basal regions of each incisor. The tooth was pushed out of the alveolar bone in an extrusive direction at 5 mm/min using a materials testing machine. The maximum shear stress, maximum shear strain, tangent modulus, and failure strain energy density were estimated from the resulting stress-strain curve. Polarized light microscopic observations of collagen fibers were also made. RESULTS: All the biomechanical measures tended to decrease from the incisal toward the basal regions in all species. There were large species differences, especially in the incisal region, with the greatest maximum shear stress and failure strain energy density in hamsters. The greatest tangent modulus and the smallest maximum shear strain were observed in mice. The birefringent fiber architectures of the periodontal ligaments in the four species appeared to be similarly organized; the incisal periodontal ligament appeared to have more organized and thicker collagen fibres than did the middle and basal ligaments in the four species. CONCLUSIONS: These results suggest that the regional differences in the biomechanical properties of the periodontal ligament depend upon the developmental stages of the periodontal collagen fibers that may be related to the general arrangement, diameters, and densities of the collagen fiber bundles and the fiber insertions into the alveolar bone and cementum. The species differences in the biomechanical properties may be due to differences in the width of the periodontal ligament and the waviness as well as the strength and stiffness of the periodontal collagen fibers.

Animals↗
PubMed1998

Carrier-mediated entry of 4-methylumbelliferyl sulfate: characterization by the multiple-indicator dilution technique in perfused rat liver.

The hepatocellular entry of 4-methylumbelliferyl sulfate (4MUS) a highly ionized and highly bound anion capable of futile cycling, was examined in the single-pass albumin-free perfused rat liver preparation. Desulfation of 4MUS to 4-methylumbelliferone (4MU) was verified in vitro to be a low-affinity, high-capacity process (Km = 731 micromol/L; Vmax = 414 nmol min(-1) g(-1) liver). With 4MUS given to the perfused rat liver, sulfation of 4MU, the formed metabolite, was attenuated in the presence of 2,6-dichloro-4-nitrophenol (DCNP), a sulfation inhibitor, and when sulfate ion was substituted by chloride ion. 4MU sulfation, being a high-affinity system, was reduced most effectively at the lowest 4MUS concentration (15 micromol/L) used, evidenced by the increased (24%) net hepatic extraction ratio of 4MUS and reduced utilization (72%) of infused tracer 35SO4(2-) by 4MU for 4MU35S formation. Single-pass multiple indicator dilution (MID) studies were thus conducted under identical conditions (DCNP and absence of inorganic sulfate), with injection of [3H]4MUS and a set of noneliminated vascular and cellular reference indicators into the portal vein (prograde) or hepatic vein (retrograde), against varying background bulk concentrations of 4MUS (5 to 900 micromol/L). The steady-state removal rate of 4MUS and formation rates of 4MU and its glucuronide conjugate (4MUG) were not altered with perfusion flow direction, suggesting the presence of even or parallel distributions of 4MUS desulfation and 4MU glucuronidation activities. When the outflow dilution profile of [3H]4MUS was evaluated with the barrier-limited model of Goresky, a slight red cell carriage effect was found for 4MUS. The permeability surface area product for cellular entry for prograde showed a dramatic concentration-dependent decrease (from 0.13 to 0.01 mL sec(-1) g(-1), or 7.4 to 0.56 times the blood perfusate flow rate) and was resolved as saturable and nonsaturable components, while data for retrograde were more scattered, varying from 2.8 to 1 times the blood perfusate flow rate. Efflux (coefficient = 0.0096 +/- 0.0024 and 0.0088 +/- 0.0062 mL sec(-1) g(-1), respectively) was relatively insensitive to concentration and flow direction. The same was observed for the removal capacity for metabolism and excretion (sequestration coefficient: for prograde, 0.0056 +/- 0.0017 mL sec(-1) g(-1); for retrograde, 0.0056 +/- 0.003 mL sec(-1) g(-1)). The decrease in the apparent partition coefficient (ratio of 4MUS concentration estimated in tissue to unbound plasma concentration) and the increase in relative throughput component with concentration further substantiate the claim on the presence of concentrative processes at the sinusoidal membrane.

Animals↗
PubMed1998

The effects of coenzyme Q10 treatment on maternally inherited diabetes mellitus and deafness, and mitochondrial DNA 3243 (A to G) mutation.

The characteristic clinical features of diabetes mellitus with mitochondrial DNA (mtDNA) 3243(A-G) mutation are progressive insulin secretory defect, neurosensory deafness and maternal inheritance, referred to as maternally inherited diabetes mellitus and deafness (MIDD). A treatment for MIDD to improve insulin secretory defects and reduce deafness has not been established. The effects of coenzyme Q10 (CoQ10) treatment on insulin secretory response, hearing capacity and clinical symptoms of MIDD were investigated. 28 MIDD patients (CoQ10-DM), 7 mutant subjects with impaired glucose tolerance (IGT), and 15 mutant subjects with normal glucose tolerance (NGT) were treated daily with oral administration of 150 mg of CoQ10 for 3 years. Insulin secretory response, blood lactate after exercise, hearing capacity and other laboratory examinations were investigated every year. In the same way we evaluated 16 MIDD patients (control-DM), 5 mutant IGT and 5 mutant NGT subjects in yearly examinations. The insulin secretory response assessed by glucagon-induced C-peptide secretion and 24 h urinary C-peptide excretion after 3 years in the CoQ10-DM group was significantly higher than that in the control-DM group. CoQ10 therapy prevented progressive hearing loss and improved blood lactate after exercise in the MIDD patients. CoQ10 treatment did not affect the diabetic complications or other clinical symptoms of MIDD patients. CoQ10 treatment did not affect the insulin secretory capacity of the mutant IGT and NGT subjects. There were no side effects during therapy. This is the first report demonstrating the therapeutic usefulness of CoQ10 on MIDD.

Adult↗
PubMed1998

No Mycobacterium paratuberculosis detected in intestinal tissue, including Peyer's patches and lymph follicles, of Crohn's disease.

To clarify the etiologic significance of Mycobacterium paratuberculosis in Crohn's disease, we investigated whether M. paratuberculosis was detected in intestinal tissues, including Peyer's patches, where M. paratuberculosis invades, and colonic lymph follicles, where early lesions appear. Fifty-one samples of intestinal tissues, either therapeutically resected or biopsied, including 34 specimens from 30 patients with Crohn's disease, were studied. Four Peyer's patches and eight lymph follicles were included in the intestinal tissue samples of Crohn's disease. They were visualized by acetic acid fixation. DNA extracted from intestinal tissues by proteinase K treatment was used for nested polymerase chain reaction (PCR) for detection of IS900, which is specific for M. paratuberculosis. PCR products were analyzed by agarose gel electrophoresis and subsequent Southern blot analysis. Our amplification system could detect 7.5 fg of M. paratuberculosis DNA. None of the tissue samples showed positive IS900 amplification, whereas they all showed amplification of the positive control human leukocyte antigen (HLA)-DQA DNA. Spiked experiments of tissue samples with M. paratuberculosis demonstrated that inhibitors of IS900 amplification were not present in the samples. Our study does not support the etiologic significance of M. paratuberculosis in Crohn's disease.

Adolescent↗
PubMed1998

Pancytopenia associated with 5-aminosalicylic acid use in a patient with Crohn's disease.

We report a case of pancytopenia in a 23-year-old man with Crohn's disease who was treated with 5-aminosalicylic acid (Pentasa; Nisshin, Tokyo, Japan) 3.0 g/day. He developed fever, nausea, diarrhea, and malaise and stopped taking on the third day after commencing Pentasa. Ten days after withdrawal of Pentasa, he was admitted to hospital because of worsening symptoms. Hematologic evaluation disclosed pancytopenia: red blood cells 283 x 10(4)/mm3; white blood cells 700/mm3; and platelets 8000/mm3. Other pertinent laboratory data, including liver and renal function tests results, serology for virus infection, and serum levels of vitamin B12 and folic acids, were normal. Bone marrow examination showed a generalized hypocellular picture, suggestive of drug-induced bone marrow suppression. He received blood transfusion and recombinant human granulocyte colong-stimulating factor (filgrastim). The leucopenia and thrombocytopenia resolved on the 7th and 13th days of hospitalization, respectively. The anemia continued because of bloody stool caused by Crohn's disease. However, reticulocytes were markedly increased in number on the 13th day of hospitalization. He is well at 9 months follow-up. Excluding other causes, Pentasa-associated pancytopenia was considered. The increasing use of this agent is expected, because of the increasing number of patients with inflammatory bowel disease. Careful clinical and hematological monitoring should be performed, especially for the first 3 months, in patients beginning treatment with Pentasa. The drug should be withdrawn immediately if there is a suspicion of blood disorders.

Adult↗
PubMed1998

Endoscopic sphincterotomy and laparoscopic cholecystectomy in an infant with cholecysto-choledocholithiasis.

Laparoscopic cholecystectomy (LC) and endoscopic sphincterotomy (EST) are widely accepted procedures for cholecysto-choledocholithiasis in adults. However, their use in infants has not been reported. An 8-month-old girl presented with high fever and obstructive jaundice. Ultrasound scan showed acute cholecystitis with stones in the bile duct. After 2-week-long antibiotic therapy the acute cholecystitis and hepatic impairment resolved. An endoscopic retrograde cholangiopancreatography (ERCP) confirmed choledocholithiasis and cholecystolithiasis. Risk factors for the development of biliary calculi were not detected. One month after the restoration of her liver function, she underwent EST using a side-viewing endoscope with a small sphincterotome. A common bile duct stone was extracted using a basket catheter. LC was then carried out. The time interval between the EST and LC was 34 days. No complications have been noted for 6 months.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1998

Microbiology of the intestinal lymph follicle: a clue to elucidate causative microbial agent(s) in Crohn's disease.

It has been suggested that microbial agent(s) are involved in the onset of Crohn's disease. None of the candidates, however, has been unequivocally demonstrated to be a causative agent. The macroscopically earliest lesion takes place in the lymph follicle, irrespective of the initial attack or relapse in Crohn's disease. Human leucocyte antigen-DR (HLA-DR) antigens are expressed on the epithelium around the lymph follicle even in areas endoscopically uninvolved in Crohn's disease. These observations make the lymph follicle critical in the onset of Crohn's disease. The lymph follicle is a port of entry of a variety of microbial agent(s), leading to the speculation that microbial agent(s) exist in the lymph follicle. Polymerase chain reaction (PCR) using universal primers designed from conserved regions of bacterial ribosomal RNA or techniques such as representational difference analysis, may well identify microbial agent(s) in the lymph follicle that are specific to Crohn's disease. The existence of bacteria in the lymph follicle is here indicated by preliminary studies.

Crohn Disease↗
PubMed1998

Listeria monocytogenes in Crohn's disease.

BACKGROUND: In an immunohistochemical study a higher rate of reactivity of intestinal tissues to the antibody against Listeria monocytogenes was reported in Crohn's disease as compared with controls. METHODS: Seventy-six intestinal tissues, either therapeutically resected or biopsied, from 31 patients with Crohn's disease, 20 with ulcerative colitis, and 21 with non-inflammatory bowel disease were studied. DNA extracted from intestinal tissues by proteinase K treatment was used for nested polymerase chain reaction (PCR), using two sets of primers. PCR products were analyzed with agarose gel electrophoresis and subsequent Southern blot analysis. RESULTS: Our amplification system could detect 9 pg of L. monocytogenes DNA. L. monocytogenes was detected in only one sample, that from a patient with ulcerative colitis. CONCLUSIONS: Our study does not support the etiologic significance of L. monocytogenes in Crohn's disease.

Adult↗
PubMed1998

Listeria monocytogenes in the colon in a case of fulminant ulcerative colitis.

A case of ulcerative colitis in which the presence of Listeria monocytogenes was confirmed in the resected colon with polymerase chain reaction and subsequent Southern blot analysis and immunohistochemistry using antibody against Listeria is presented. The patient developed ulcerative colitis at the age of 59 years. Prednisolone, 50 mg/day, was given for severe ulcerative colitis. Later the disease became fulminating, indicating colectomy 4 months after the onset. Multiple sealed colonic perforations were observed. Numerous L. monocytogenes were found at the site of perforation, in fissures, and in cracks in the submucosa. This case indicates the possibility that L. monocytogenes contributes to the exacerbation of colitis to fulminating and colonic perforation.

Colectomy↗
PubMed1998

Isolation of tick-borne encephalitis virus from Ixodes ovatus (Acari: Ixodidae) in Japan.

A case of tick-borne encephalitis (TBE) was found in a farming area located in the southern part of Hokkaido, Japan, in 1993. TBE viruses were isolated from sentinel dogs in the area where the human case occurred in 1995. Ticks were collected in the area by 2 collection methods in 1995 and virus isolation was conducted on ticks in 1995 and 1996. Ixodes ovatus Neumann was found to be the predominant tick species in the area. In 1996, 2 virus strains were isolated from 600 I. ovatus ticks (300 females and 300 males), giving the minimum infection rate of 0.33% (2 of 600). The 2 virus strains were identified as TBE virus by antigenic analysis using monoclonal antibodies and the indirect immunofluorescent antibody test. The results showed that I. ovatus was a suspected vector of the emerging TBE virus in Hokkaido.

Animals↗
PubMed1998

Portal-systemic encephalopathy from a spontaneous gastrorenal shunt diagnosed by three-dimensional computed tomography and treated effectively by percutaneous vascular embolization.

A 67-year-old man with a portal-systemic shunt confirmed by three-dimensional computed tomography (3D-CT) was successfully treated by percutaneous vascular embolization. The patient had aggravated loss of memory, disorientation, and hyperammonemia. A gastrorenal shunt 16 mm in diameter was found by 3D-CT reconstructed by helical computed tomography (CT). Embolization was performed only in the shunt percutaneously through the inferior vena cava. One year after the embolization, no recurrence of portal-systemic encephalopathy and no portal hypertension have appeared, and the clinical course has been good.

Aged↗
PubMed1998

Clinical evaluation of a leucocyte-depleting blood cardioplegia filter (BC1B) for elective open-heart surgery.

Activation of leucocytes during extracorporeal circulation has attracted attention in recent years as a cause of reperfusion injury in open-heart surgery patients. In the present study, 40 adult patients undergoing elective open-heart surgery were randomized into two groups: 20 using the Pall BC1B leucocyte-depleting filter for blood cardioplegia (group 1) and the other 20 without the filter (group 2). In order to determine if the filter was effective in protecting the myocardium, CPK-MB and troponin-T (TnT) were measured. In addition, efforts were also made to determine appropriate sites at which the BC1B blood cardioplegia filter should be positioned. There were no significant differences between the two groups in terms of conditions of perfusion. No adverse effects were seen in either group. The total leucocyte reduction rate through the filter was 98.1% with the passage of 2 liters of blood through the filter. A pressure drop of 4.4 +/- 3.2 mmHg was observed through the filter during use. Statistically significant differences were noted between the two groups in CPK-MB (p = 0.031) and TnT (p = 0.004). Findings obtained in previous studies demonstrate that the various advantages of leucocyte reduction, shown in experimental studies, can be translated into clinical advantages. In conclusion, based on the results in this clinical study showing significant difference in CPK-MB and TnT which are known effective indicators for myocardial injury, between leucoreduced and non-leucoreduced group, the Pall BC1B leucocyte-depleting filter for blood cardioplegia has been shown to be effective in alleviating reperfusion injury in open-heart surgery patients.

Adult↗
PubMed1998

Mitochondrial deoxyribonucleic acid 3256C-T mutation in a Japanese family with noninsulin-dependent diabetes mellitus.

Accumulating reports indicate a relationship between mitochondrial DNA mutation and impaired glucose-induced insulin secretion leading to a subtype of noninsulin-dependent diabetes mellitus. DNA from a 45-yr-old Japanese woman with noninsulin-dependent diabetes mellitus and muscle atrophy was isolated and studied for mitochondrial DNA mutations. We identified a mitochondrial DNA C-T heteroplasmic mutation at nucleotide position 3256. The mutation was located in the transfer ribonucleic acidLeu in a region conserved in evolution. Eight other members of her family were examined for the mutation. Six of them had the same mutation together with noninsulin-dependent diabetes mellitus, and one teenage boy had the mutation and impaired glucose tolerance. The other family member who did not have this mutation had normal glucose tolerance. The enzyme activity of the mitochondrial oxidative phosphorylation pathway in the muscle of the proband was measured. The enzyme activity was decreased in the proband, especially in complex I. This mutation might be responsible for the abnormal glucose metabolism.

Adolescent↗
PubMed1998

[A method of measuring eruptive movement of the rat incisor using a non-contacting displacement detector].

The axial movements of rat incisors were recorded continuously for over 20 hr. The rats were anesthetized with halothane delivered by intratracheal intubation using an artificial respirator. A hemostatic clamp was used to immobilize the jaw. The displacement detector that detects changes in the electric eddy current exhibited high resolution, good linearity and low drift. The average eruption rates of the rat incisor were estimated to be 406 and 516 microns/ 24 hr at 34 and 37 degrees C of the rectal temperature, respectively. The values were within the normal range. We also measured the force needed to restrain eruptive movement of the rat incisor using the same apparatus combined with a load cell. The maximum pushing force was estimated to be 9 mN or 29 mmHg (converted value) on average. Then the effects of adrenaline on axial movement of the incisor and arterial blood pressure were examined. Adrenaline caused a rapid extrusive tooth movement with a nearly simultaneous increase in the blood pressure, followed by a marked intrusive tooth movement and a decrease in blood pressure. These results support the view that the systemic arterial blood pressure and vasculature in the tooth socket play important roles to determine the position of teeth. We assume that our method would be useful to clarify the precise relationship between tooth displacement and vascular change in the tooth socket.

Alveolar Process↗