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Biomedical subjects

M Chiba

Publications and source records attributed to M Chiba.

At least 127 records · Page 7Linked to original sources
PubMed1998

Pharmacological activities of khellactones, compounds isolated from Peucedanum japonicum THUNB. and Peucedanum praeruptorium DUNN.

The spasmolytic and antiallergic effects of AA and BB, compounds isolated from Peucedanum japonicum THUNB. (P. japonicum THUNB.) and Peucedanum praeruptorium DUNN. (P. praeruptorium DUNN.), were investigated in isolated smooth muscle and rat PCA. AA and BB showed noncompetitive antagonistic effects on Ach- and histamine-induced contraction in the isolated guinea pig ileum. Both AA and BB at 10(-6) g/ml caused a slight shift to the right of the dose-response curve for Ca2+ in isolated guinea pig ileum, and a concentration up to 3 x 10(-6) g/ml displayed noncompetitive antagonistic effects. The Ba2+ (3 x 10(-4) g/ml)-induced contraction in ileum and the histamine (10(-3) g/ml)-induced contraction in trachea were obtained to relaxation by AA and BB in a concentration-dependent fashion. AA and BB showed noncompetitive antagonist action on serotonin-induced contraction of the rat uterus excised 24-48 h after subcutaneous injection of female rats with estradiol. But, AA and BB were found to have hardly any inhibitory effect on rabbit thoracic aorta contractions induced by epinephrine (3 x 10(-6) g/ml). When the effect of oral administration of 40 mg/kg dose of BB was tested on the rat homologous PCA using anti-egg albumin mouse serum dilutions (1:100, 1:250, 1:500 and 1:750), it inhibited the 1:750 serum reaction 42.6%, but the inhibition rates for the other dilutions were 12-20%. Thus, based on the results of testing AA and BB, compounds isolated from P. japonicum THUNB. and P. praeruptorium DUNN. were confirmed to possess a spasmolytic effect on different types of smooth muscle and a mild antiallergic effect. These findings are of interest in regard to the medical uses of P. japonicum THUNB. and P. praeruptorium DUNN. as a herbal drug for bronchial asthma, spasmolytic effect, etc.

Animals↗
PubMed1998

Effects of exercise at different ages on bone density and mechanical properties of femoral bone of aged mice.

We determined the bone density and mechanical properties of bone specimens from 5 groups of aged mice, which had been subjected to voluntary exercise at different ages. ICR 10-week-old female mice were divided into control (C), and exercise-trained during age periods of 10-70 weeks (EE), 10-30 weeks (GPE), 30-50 weeks (MPE) and 50-70 weeks (APE). It was found that in the exercise-trained groups body weight gain was suppressed during the exercise-training period, and that de-training accelerated weight gain. Bone density was significantly higher in all the exercise-trained groups than in the C group and cortical thickness index (CTI) was higher in the exercise-trained groups, except for the APE group. Maximum breaking force, ultimate stress and elasticity in the exercise-trained groups were higher than in the C group except for the APE group, whereas deformation in the APE group had a tendency to be higher than in the other groups. Blood C-terminal parathyroid hormone, calcitonin and calcium concentrations were similar among every group, but phosphorus concentrations tended to be higher in the exercise-trained groups than in the C group. These observations suggest that exercise-training at every age suppresses age-associated bone loss, and that the effect of exercise during youth is greater than that during old age. The results of this study suggest that the effect of exercise on bone at an older age is different from that at other ages.

Aging↗
PubMed1998

Studies on lead-binding protein and interaction between lead and selenium in the human erythrocytes.

To clarify the function of Pb-binding protein and the interaction between lead and selenium in human erythrocytes, the following experiments were performed. (a) blood from a man who has not been exposed to lead occupationally, (b) blood from lead-exposed workers and (c) blood from control subjects working in the same plant were used. (a) was incubated with Pb and/or Se. Hemolysates of rinsed erythrocytes were applied onto a Bio-gel A 1.5 m column and eluted by 40 mM Tris-HCl buffer (pH 7.0). As the results, (1) Pb in erythrocytes was found in ALAD fraction. When Pb was added in vitro at 1.25 microM of final concentration, Pb content of ALAD fraction increased and the other Pb-containing fraction appeared at the position of a smaller molecular size than that of Hb fraction. When Pb dose added was increased to 2.5 or 10 microM, Pb contents in the newly appeared fraction was larger than that in ALAD fraction. The affinity of Pb with the protein in the new fraction was weak, and Pb was released from the protein by ultrafiltration. (2) There were main and sub-peaks containing Pb in erythrocytes from Pb-workers; the former was ALAD fraction and the others were smaller molecules than ALAD. The peak of Pb observed with the blood from a worker who has worked at the same plant for more than 20 years (chronic exposure) corresponded with the new peak which appeared in vitro Pb exposure. (3) As to the interaction between Pb and Se, there was no effect of Se added in vitro on the position of Pb-containing fraction and on Pb amounts in the chromatographic profile. When Se was incubated with blood, however, coexistence of Pb made Se concentration in erythrocytes high compared with the case of Se alone.

Carrier Proteins↗
PubMed1998

Induction of major histocompatibility complex class II antigens on human colonic epithelium by interferon-gamma, tumor necrosis factor-alpha, and interleukin-2.

Class II antigens are strongly expressed on the inflamed colonic epithelium in inflammatory bowel disease. However, the mechanism of this epithelial class II antigen induction is not fully understood. Increased activities of interferon (IFN)gamma, tumor necrosis factor (TNF)alpha, and interleukin (IL)2 have been shown in the inflamed mucosa of inflammatory bowel disease. Therefore, we studied whether these cytokines could induce class II antigens on the human colonic epithelium. By an organ culture technique, 284 normal colonic biopsy specimens obtained from 49 individuals were cultured in media containing different concentrations of cytokines with/without anti-IFNgamma R antibody. Colonic epithelial class II antigens were identified by the indirect immunoperoxidase staining method with anti-human leukocyte antigen (HLA)-DR, DP, and DQ monoclonal antibodies. IFNgamma, TNFalpha, and IL2 induced epithelial class II antigens in 16 of 16 cases (100%), 2 of 16 cases (12.5%), and 6 of 17 cases (35%), respectively. Epithelial class II antigen expression in response to TNFalpha was induced via IFNgamma but not via IL2. This is the first demonstration that: (i) the induction of class II antigens on the colonic epithelium in response to TNFalpha is mediated via IFNgamma, and (ii) that IL2 induces class II antigens.

Epithelial Cells↗
PubMed1998

[Assessment of enlarged left atrium with 99mTc-tetrofosmin SPECT and echocardiography].

This study was performed to clarify the possibility of visualization and quantification with 99mTc-tetrofosmin (Tf) myocardial scintigraphy in cases with a large atrium demonstrated by trans-thoracic echocardiography (TTE). Myocardial SPECT was evaluated in 4 patients with mitral stenosis and 15 patients with mitral regurgitation. Left atrium was identified in 12 out of 19 cases from an antero-posterior projection. The Tf uptake ratio of the left atrium, which was defined as the ratio of ROI count of the left atrium divided by the ROI count of the left ventricle, showed a good correlation with the left atrial area obtained by both trans-thoracic and trans-esophageal echocardiography (r = 0.88 and 0.91, respectively), These data suggest that Tf myocardial SPECT is a useful method of evaluating left atrial enlargement.

Aged↗
PubMed1998

Bone density and mechanical properties in femoral bone of swim loaded aged mice.

Effects of swimming on bone density and mechanical properties of femur were investigated in aged male and female mice. R/1 strain of senescence accelerated mouse (SAM) at eleven months old was used. Two groups of males and two groups of females each consisting of 7 mice were used. One male and one female groups were loaded with a swim regiment of 40 min a day, 5 days a week for 6 consecutive weeks. The remaining groups were used as the controls. All mice were fed with the standard diet and water ad libitum during the experiments. The results of this study indicated that (i) the body weight was significantly (P < 0.05) lower in the swimming groups than in the control groups in both sexes. (ii) The bone density was significantly higher (P < 0.05) in the swimming groups than in the control groups in both sexes. However, there was no significant difference in cortical thickness index. (iii) In the mechanical properties of bone, there were no significant differences in the level of the maximum breaking force, the ultimate stress and the deformation between the swimming and the control groups in both sexes. However, the elasticity of the bone of the female mice in the swimming group was significantly higher (P < 0.05) than that of the control group. These results suggest that regimented swimming for the aged mice might suppress age-associated bone loss, and the effect of exercise in the females is greater that in the males.

Aging↗
PubMed1998

[Investigating methods for age estimation (1). Height of the apex of the medullary cavity of the humerus].

The relationship between age and the height of the proximal apex of the medullary cavity of humerus was investigated on 13 male bodies (29-62 years) and 12 female bodies (22-80 years) and a provisional criterion for age estimation was obtained. When the apex is (1) at a height of the surgical neck, the estimated age is under 50 years in both sexes, (2) at the epiphyseal line, over 50 years in males, and from 50 to 75 years in females. In a few cases, however, the apex reaches the line even in the very young age group (20-30 years). (3) When a cavity or rough structure is present above the line in addition to phase (2), the estimated age is over 75 years in females, but unknown in males. We also discuss the validity of Koshinaga's criterion (1951).

Adult↗
PubMed1997

Hepatic and intestinal metabolism of indinavir, an HIV protease inhibitor, in rat and human microsomes. Major role of CYP3A.

The metabolism of indinavir, a human immune deficiency virus (HIV) protease inhibitor, has been characterized extensively in rats and humans. All oxidative metabolites found in vivo were formed when indinavir was incubated with NADPH-fortified hepatic and intestinal microsomes obtained from rats and humans. In vitro kinetic studies revealed that Vmax/Km values (microL/min/mg protein) in rat and human liver microsomes were approximately 8- and 2-fold greater than those in the intestinal microsomes of the corresponding species (55.8 and 6.7 for the liver and intestine, respectively, in rats; 16.5 and 7.7 for the liver and intestine, respectively, in humans). However, when Vmax/Km was scaled up to intrinsic clearance (mL/min/kg body weight), hepatic intrinsic clearance was much greater than the intestinal clearance by 50- to 200-fold. These results suggest that the liver plays a much greater role in first-pass metabolism of indinavir than the intestine in both species. Consistently, ketoconazole, a selective inhibitor for CYP3A, and an anti-rat CYP3A1 antibody strongly inhibited hepatic and intestinal metabolism of indinavir in both rats and humans, suggesting the involvement of CYP3A isoforms in both organs. Oral treatment of rats with dexamethasone (50 mg/kg/day for 4 days), a potent CYP3A inducer, increased both hepatic and intestinal metabolism of indinavir by a factor of 7 and 3, respectively. Furthermore, indinavir selectively inhibited 6beta-hydroxylase activity of testosterone, a CYP3A marker activity, in rat and human liver microsomes; the interactions between testosterone and indinavir were competitive with Ki values of < 1.0 microM.

Animals↗
PubMed1997

Effect of the maze procedure for atrial fibrillation on atrial and brain natriuretic peptide.

We studied plasma levels of atrial and brain natriuretic peptides at rest and after exercise before and after intracardiac surgery with and without the maze procedure in patients with chronic heart failure secondary to valvular heart disease. The present study found that an increased response of both cardiac natriuretic peptides is attenuated with resulting water retention after the maze procedure.

Atrial Fibrillation↗
PubMed1997

Thoracolumbar burst fracture with horizontal fracture of the posterior column.

STUDY DESIGN: Nine patients with thoracolumbar burst fractures associated with horizontal fractures in the posterior column were studied retrospectively. OBJECTIVES: To clarify the clinical and radiographic findings and evaluate the postoperative results for this type of fracture. SUMMARY OF BACKGROUND DATA: It is not well recognized that burst fractures occasionally are accompanied by horizontal fractures of the posterior column such as those that result from seatbelt-type injuries. This type of burst fracture differs from flexion-distraction injuries combined with burst fracture, which are accompanied by horizontal fractures not only in the posterior but also in the middle column. Radiographic features of these two different types of injuries are very similar to each other, and their differentiation in diagnosis and treatment has not been recognized clearly. METHODS: Patients were reviewed using a combination of clinical records, follow-up examination, and radiographic data (computed tomography [CT], plain radiographs, and tomographs). Anterior spinal fusion was performed in eight patients using the Kaneda device (Mizuhoika Tokyo, Japan), and one was treated by posterior fusion with pedicle screw fixation. The average follow-up period was 4 years. RESULTS: Patients with fractures of this type represented 21% of the 48 patients with thoracolumbar burst fractures. The injury was sustained by falling in all nine patients. All of the burst fractures were Denis' type B. The horizontal fracture was located at the lamina and spinous process in the posterior column of the upper vertebra adjacent to the involved vertebra in all nine patients. The integrity of the ligamentous structures of the middle column, such as the posterior longitudinal ligament, the periosteum, and the outermost anulus, was confirmed at surgery in eight patients, although not in the patient who underwent posterior fusion. One patient required surgery because of progression of kyphotic deformity during conservative treatment. Solid fusion with no complications was noted in all patients. CONCLUSION: This type of burst fracture is not accompanied by ligamentous injuries because of distraction force in the middle column, which is not present in flexion-distraction injuries, but it seems to be more unstable than burst fractures with no horizontal splitting of the posterior column and requires surgical stabilization.

Adult↗
PubMed1997

Crohn's disease associated with renal amyloidosis successfully treated with an elemental diet.

We report a case of Crohn's disease associated with nephrotic syndrome due to renal amyloidosis in a 21-year-old man in whom remission of both Crohn's disease and the nephrotic syndrome has been maintained with an elemental diet. The patient developed toxic megacolon and nephrotic syndrome due to renal amyloidosis. Intensive intravenous prednisolone therapy with total parenteral nutrition was dramatically effective in treating the toxic megacolon and inducing remission in Crohn's disease and afterward, remission of the nephrotic syndrome. Remission of both conditions has been maintained for more than 2 years with the elemental diet. To our knowledge, this is the first confirmed case of Crohn's disease complicated with renal amyloidosis in which only slight proteinuria (below 0.3 g/day) was shown with an elemental diet used for a long period.

Adult↗
PubMed1997

Three cases of familial ulcerative colitis--in a mother and two of her sons.

A pedigree of familial ulcerative colitis with their HLA haplotypes is reported. The mother and two children, the eldest and second of three sons were affected. The mother developed proctitis at age 35, and the lesion extended to the entire colon at the time of a relapse. The two sons developed ulcerative colitis in a similar fashion; total colitis, of moderate severity, developing at age 16 in both. The analysis of HLA haplotypes of all five family members suggested that the HLA responsible for ulcerative colitis in this family was not HLA B, C, or DR, but Aw24 and DQw1. The third son had the same HLA haplotype as the second son, and it was presumed that he would develop ulcerative colitis in the future. These cases, together with other cases of familial ulcerative colitis indicate that Aw24 and DQw1 are critical phenotypes for ulcerative colitis in Japan.

Adolescent↗
PubMed1997

Metastatic Crohn's disease involving the penis.

Metastatic Crohn's disease is a rare complication in Crohn's disease and there have been only several cases of metastatic Crohn's disease involving the penis. We report one such case. A 22-year-old male student developed anal pain and alternative constipation and diarrhea in December, 1985, followed by diarrhea and lower abdominal pain in January, 1986. He was diagnosed as having Crohn's disease of ileocolitis type. He was admitted to our hospital in July, 1987 because of exacerbation of Crohn's disease. He had anal tags. Soon after admission, two red swollen lesions with central ulcer and erosions were demonstrated at the eversion of the foreskin adjacent to coronal sulcus. Histology of the lesions revealed granulomas with epithelioid cells and giant cells. The lesion responded to a topical steroid. Eight cases of metastatic Crohn's disease involving the penis are briefly reviewed.

Adult↗
PubMed1997

Dose-response effects of adrenergic drugs on axial movements of the rat mandibular incisor and on arterial blood pressure.

Axial tooth movements and arterial blood pressure were measured following the intravenous injection of 0, 0.01, 0.1, 1, or 10 micrograms/kg of adrenaline, noradrenaline or isoprenaline. Adrenaline caused a dose-dependent, rapid, extrusive tooth movement with a nearly simultaneous increase in blood pressure, followed by a marked intrusive tooth movement and a decrease in blood pressure. Noradrenaline caused a dose-dependent, rapid, extrusive tooth movement and an increase in blood pressure, but a subsequent intrusive tooth movement and decrease in blood pressure were not so marked. Isoprenaline caused a marked intrusive tooth movement and a decrease in blood pressure, without an extrusive tooth movement and increase in blood pressure. The time required to reach the maximum intrusive tooth movement was delayed after that to reach the maximum decrease in blood pressure. The recovery time of the intrusive tooth movement was much more delayed than that of blood pressure. These results suggest that the extrusive movement of the rat incisor was primarily related to the rise of arterial blood pressure due to stimulation of vascular alpha-receptors. It is also suggested that stimulation of beta-receptors would probably cause vasodilatation of arteries that would make the pressure in the small vessels in the microcirculation of the socket fall, so reducing the volume of blood and interstitial fluid in the socket followed by a marked and continuing intrusive tooth movement.

Adrenergic Agonists↗