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Biomedical subjects

M Chiba

Publications and source records attributed to M Chiba.

At least 289 records · Page 16Linked to original sources
PubMed1989

HLA-DR antigen expression in macroscopically uninvolved areas of intestinal epithelia in Crohn's disease.

HLA-DR antigens in small and large intestinal epithelia were examined in Crohn's disease (CD). Seventy-two biopsy specimens (10 from the duodenum, 18 from the terminal ileum, and 44 from various sites of the large intestine) were obtained from 5 patients with CD chronologically; before treatment, during elemental diet (ED) treatment, and during home elemental enteral hyperalimentation (HEEH). HLA-DR antigens on the intestinal epithelia were identified by the indirect immunoperoxidase staining method using two mouse anti-HLA-DR monoclonal antibodies. In the small intestine, HLA-DR antigens were expressed differently from normal controls in macroscopically or microscopically pathological areas, but not in macro- or microscopically normal areas. In the large intestine, when the disease was in full vigor before treatment, HLA-DR antigens were always aberrantly expressed even in the macroscopically uninvolved areas, as well as in macroscopically involved areas. However, when the disease was suppressed after ED followed by HEEH treatment, the antigens were not always expressed in the macroscopically uninvolved areas, or in the macroscopically involved areas. These findings suggest that HLA-DR antigens are not merely expressed as a non-specific response to inflammation, but may be expressed as a primary change which results in macroscopic lesions. The possible role of HLA-DR antigens in the immunological mechanism in CD is proposed.

Adult↗
PubMed1989

Role of adrenergic receptor systems in canine left ventricular hypertrophy.

Although the sympathetic nervous system and catecholamines have been postulated to play an important role in the development of myocardial hypertrophy, the precise mechanism is still ill-defined. We therefore investigated myocardial norepinephrine and the adrenergic receptor systems in two experimental canine models for cardiac hypertrophy; in 12 dogs with surgical cardiac denervation, and in 12 dogs with chronic infusion of a subhypertensive dose of norepinephrine at a rate of 0.04 mg/kg/day. After two months both models induced myocardial hypertrophy, indicated by significant increases in the heart weight, left ventricular wall thickness and cell diameter, as compared with 14 sham-operated control dogs. Cardiac denervation remarkably depleted myocardial norepinephrine while plasma norepinephrine remained unchanged. Both alpha 1- and beta-receptors were up-regulated, with Bmax increasing by 124% and 49%, respectively. The decrease in myocardial cyclic AMP content was relatively small as compared with the marked depletion in myocardial norepinephrine, probably compensated by augmentation of beta-receptor system activity. Chronic norepinephrine infusion also reduced myocardial norepinephrine content possibly due to stimulation of presynaptic alpha 2-receptor inhibiting norepinephrine synthesis and release. The number of alpha 1- and beta-receptors also increased by 97% and 30%, respectively, while myocardial cyclic AMP content remained unchanged. These observations indicate that neither direct stimulation of norepinephrine on the myocardial cell nor increased cyclic AMP is the mechanism for cardiac hypertrophy. A greater increase in the alpha 1-receptor, rather than in the beta-receptors, in both models implies that a disproportional augmentation of the alpha 1-receptor system may play an important role in the development of myocardial hypertrophy.

Animals↗
PubMed1989

Effects of lathyrogens on the mechanical strength of the periodontal ligament in the rat mandibular first molar.

Effects of lathyrogens such as aminoacetonitrile (AAN), beta-aminopropionitrile (BAPN) and cysteamine--known inhibitors of cross-linking of collagen--on the mechanical strength of the periodontal ligament of the rat mandibular first molar were examined by measuring the ultimate load required to extract the tooth from its socket in the dissected jaw. Single injections of AAN (40 approximately 100 mg/100 g body weight) or of BAPN (100 mg/100 g body weight) caused significant decreases of the mechanical strength 24 h after administration of the drugs but that of cysteamine (30 mg/100 g body weight) did not. Significant correlations between the dose of AAN or of BAPN and the mechanical strength were found following daily administrations of the drugs for 5 days. The relative potency of AAN to BAPN was estimated to be 4.5 by a slope ratio assay. The rapid appearance and disappearance of the effect of lathyrogens on the mechanical strength of the periodontal ligament of the rat mandibular first molar provide further evidence that the turnover of the collagen in the tissue is fast. The half-time of collagen synthesis was estimated to be approximately 3 d.

Acetonitriles↗
PubMed1989

Responses of myocardial blood flows to whole-body vibration in the dog.

Experimentally acute exposure to whole-body vibration resulted in changes in myocardial blood flows in the in vivo dog. Regional myocardial blood flows measured by a hydrogen gas clearance method were increased at a vibration frequency of 120 Hz and decreased at 50 Hz. No appreciable changes were found in presence of a beta-adrenergic blocker. The values of plasma cyclic nucleotides were increased at both frequencies of vibration, more at 50 Hz than at 120 Hz. No significant changes were observed in heart rates and arterial pressure during and after vibration load. These findings suggest that increased myocardial blood flows in response to vibration may be related more to the frequency of vibration than to beta-adrenergic actions.

Animals↗
PubMed1989

Effect of dentin cleansers on the bonding efficacy of dentin adhesive.

The relation between the bonding efficacy of the dentin adhesive and the physical change of the dentin after treatment with various dentin cleansers was investigated. The dentin surface was cleaned with one of the seven experimental dentin cleansers, 5, 10, 20, 30 and 40% of the phosphoric acid, neutralized 0.5 M EDTA solution (pH 7.4) and 9.1% pyruvic acid containing 9.1% glycine, prior to the combining application of 35% hydroxyethylmethacrylate solution (HEMA) and a marketed dentin bonding agent. It was found that the bonding efficacy of the dentin bonding system employed in this study deteriorated with the degree of reduction of Vickers hardness on the dentin surface after the dentin cleaning.

Acid Etching, Dental↗
PubMed1989

[Successful treatment of cheilitis granulomatosis with potent inhibitors of mediator release--possible involvement of mast cells in the pathogenesis].

We report two cases of patients with cheilitis granulomatosis treated successfully with tranilast and ketotifen, both of which are known to be potent inhibitors or mediator release from mast cells. In one patient, complete resolution of the lesion occurred after 1 year of therapy. In another patient, the lesion also showed consistent, if not complete, improvement during the course of therapy. Because of the mechanism of the action, these agents have been widely used as therapeutic modalities for mast-cell-related diseases. We therefore measured numbers of mast cells in the lesions of cheilitis granulomatosis, in comparison with those in mucous cyst and lichen planus. Light microscopy of toluidine-blue-stained sections showed that mast cells, particularly those with ongoing degranulation, increased in number in the reticular dermis of the lesions of cheilitis granulomatosis. These findings suggest that mediators released from mast cells may be critical for the granulomatous inflammation in cheilitis granulomatosis.

Adolescent↗
PubMed1989

[Concentric left ventricular hypertrophy in patients with aortic regurgitation].

Chronic aortic regurgitation (AR) is a disease incorporating volume overload of the left ventricle (LV) which is characterized by hyperactive left ventricular dilatation (LVD). However, we have encountered several patients who had concentric LV hypertrophy (LVH) instead of LVD. We therefore studied 50 consecutive patients with isolated AR but without aortic stenosis and found seven patients with concentric LVH having LV wall thickness (determined by summing ventricular septal and posterior wall thicknesses) exceeding 30 mm and LV diastolic diameters of less than 60 mm. These seven patients with AR and LVH were older (55 +/- 27 vs 42 +/- 11 years) and tended to have milder degree of AR, compared with the remaining 43 patients having AR and LVD. However, patients with AR and LVH did not differ from AR and LVD as to the cardiothoracic ratio, SV1 + RV5, T-waves, ejection fraction, operative findings of valvular morphology and underlying etiologies. In contrast, patients with AR and LVH presented higher systolic (196 +/- 41 vs 149 +/- 26 mmHg, p less than 0.01) and diastolic pressures (74 +/- 14 vs 51 +/- 13 mmHg, p less than 0.01) and higher systemic vascular resistance (1,854 +/- 399 vs 1,388 +/- 352 dyne.sec.cm-5, p less than 0.05) during catheterization than did those with AR and LVD. However, blood pressure at the time of admission was not different in the two groups. These observations indicate that concentric LVH is not rare among patients with AR, and that an association of pressure overload with volume overload of the LV, particularly during exercise or stress, may lead to concentric LVH, even in patients with chronic AR.

Adult↗
PubMed1989

[Study of bone remodeling mechanism induced by mechanical stress. Differentiation of osteoclasts induced by compressive force in newborn rat cultured long bone].

The purpose of this investigation was to reveal the mechanism of differentiation of osteoclast (OC) induced by mechanical stress in long bone cultivation of new born rats. A long bone was loaded with 30 gf of continuous compressive force and cultured for 5 days in CO2 incubator. Numbers of OC increased in the long bone were counted after H-E staining and compared with the control. The study was dealt with the effects of recombinant tumor necrosis factor alpha (rTNF alpha), recombinant interleukin-1 beta (rIL-1 beta), prostaglandin E2 (PGE2) and the co-cultivation of osteoblast (OB) originated from new born rat calvariae, as to differentiation of OC. Since the bone remodeling was interacted with OB and bone marrow (BM) cells, the activity of alkaline phosphatase (ALPase) was also investigated for OB in co-cultivation with BM cells originated from new born rat long bones. In the region of diaphysis of a long bone loaded with compressive force, the bend of trabecular bones was noticed after 3 days incubation. Also, the enrichment of monocyte-macrophage (Mo-M phi) lineage cells was noticed along the trabecular bones. After 5 days incubation, the increase of the number of OC was specifically recognized. The increase of the number of OC was shown in medullary cavity of the long bone by addition of rTNF alpha to the culture medium, but any synergistic effect was not shown with the treatment of rTNF alpha and compressive force to the increase of the number of OC. Furthermore, the increase of the number of OC induced by compressive force did not suppressed by addition of anti-TNF serum. Under the treatment of rIL-1 beta or PGE2, OC slightly increased in the long bone when loaded by compressive force, but the treatment of indomethacin did not suppress it completely. However, the increase of OC in the long bone loaded by compressive force was clearly inhibited in co-cultivation with OB. On the other hand, the activity of ALPase of OB was markedly abated in co-cultivation with BM cells. These results indicated that the mechanism of differentiation of OC induced by mechanical stress was different from that induced by the general inflammation. Results also indicated that it was controlled mainly by the factor(s) or interaction between BM cells and OB and was associated with Mo-M phi lineage cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Parallel pathway interactions in imipramine metabolism in rats.

The in vitro metabolic inhibitions between imipramine and its metabolites were investigated in rat liver microsomes. A type of precursor-metabolite interaction similar to that shown with lidocaine was observed in imipramine metabolism. Desipramine competitively inhibited the formation of 2-hydroxyimipramine from imipramine. Similarly, imipramine inhibited the formation of 2-hydroxydesipramine from desipramine. As in the cases of those 2-hydroxylations, a competitive inhibitory relationship also existed in the N-demethylation pathways of imipramine and 2-hydroxyimipramine. Studies on age-associated alterations of the metabolic rates of imipramine and its metabolites in rats demonstrated that N-demethylation activities of imipramine and of 2-hydroxyimipramine, which showed a large sex difference (male greater than female) in young rats, decreased markedly only in old male rats, while 2-hydroxylation activities of imipramine and desipramine, with no sex difference at any age, did not show a marked alteration in either sex. These data strongly suggest that the hydroxylation pathways of imipramine and desipramine and the demethylation pathways of imipramine and 2-hydroxyimipramine are each sharing the same species of cytochrome P-450. The in vivo metabolic inhibition between imipramine and desipramine was examined by simultaneous intraportal infusion of imipramine (25 nmol/min) and desipramine (175 nmol/min). The steady-state concentration of imipramine after simultaneous infusion was increased twofold over that after infusion of imipramine alone, without any change in the free fraction in blood.

Aging↗
PubMed1988

Anti-erythrocyte antibodies in ulcerative colitis: case report and discussion on the pathophysiology of anti-erythrocyte antibody.

A case of ulcerative colitis (UC) associated with anti-erythrocyte antibodies is reported. A 27-year-old male visited our department because of a relapse of UC, and his condition was diagnosed as severe and extensive colitis. He was vigorously treated with prednisolone (50 mg/day i.v.) and TPN, but no response was obtained. Subtotal colectomy with ileostomy was performed on the 22nd hospital day, and a proctosigmoidectomy was performed on him six months later. Preoperative blood type and screen disclosed that his blood was not cross-matched either on the forward or reverse typing. His ABO blood group could not be identified as "B", as determined upon admission, and his Coombs' test was positive. Further studies revealed that his Rh group was CcDEe. Anti-I antibody was detected in his serum and eluate from erythrocytes were identified as anti-E and c. Titers of the antibodies were strongest in the preoperative period and became weak following colectomy, but the antibodies did not disappear even after the large bowel was totally removed.

Adult↗
PubMed1988

Ubiquitous expression of HLA-DR antigens on human small intestinal epithelium.

To clarify the frequency of the expression of HLA-DR antigens on the human small intestinal epithelium and the variation of such expression, 43 specimens (duodenum 16, jejunum 8, ileum 19; histologically normal 33, pathologic lesions 10) were studied for HLA-DR expression by indirect immunoperoxidase staining using monoclonal antibodies against HLA-DR antigens. All specimens reacted with anti-HLA-DR antibodies with minor variations. Most specimens showed decreasing intensity from the top of the villi toward the base of the villi and no staining in the crypt. In about half of the specimens, clear peripheral and cytoplasmic staining of the epithelial cells was observed. In some cases, the staining of the apical portion of the epithelium was patchy. The expression was unrelated to the lymph follicle. This ubiquitous expression of HLA-DR antigens on the small intestinal epithelium presents a striking contrast to an absence of the antigens on the normal large intestinal epithelium. A preliminary study on the pathologic lesions demonstrated the following changes in the expression of HLA-DR antigens; appearance of HLA-DR antigens on the crypt epithelium in Crohn's disease, loss of HLA-DR antigens on the epithelium covering the area of cell infiltration in macroglobulinemia and covering adenoma in familial polyposis coli.

Antibodies, Monoclonal↗
PubMed1988

Immunopathologic study of lichenoid skin diseases: correlation between HLA-DR-positive keratinocytes or Langerhans cells and epidermotropic T cells.

Skin biopsy specimens from 24 patients with different lichenoid skin diseases that had been proved histologically were studied immunohistologically. Marked differences were noted in the number of OKT6+/S100+ Langerhans cells within the epidermis and dermis in the lesional skin between lichen planus (and its related disease) and lupus erythematosus; in the former these cells were increased in number; in the latter they were decreased in number compared with those in uninvolved perilesional skin. Human lymphocyte antigen (HLA)-DR expression on keratinocytes was observed not only in lichenoid skin diseases but also in control cases without epidermal involvement. In the two cases of systemic lupus erythematosus, the uninvolved perilesional skin also show weak and focal HLA-DR reactivity in the basal layer. HLA-DR+ keratinocytes could play an important role at least in the perpetuation of epidermal cell damage mediated by T cells.

Epidermis↗