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Biomedical subjects

A Yamaguchi

Publications and source records attributed to A Yamaguchi.

At least 271 records · Page 15Linked to original sources
PubMed1996

Video-assisted thoracic surgery for thorascopic resection of giant bulla.

This report outlines our experience of 6 patients who underwent video-assisted thoracic surgery (VATS) using a linear endoscopic stapler to remove a giant bulla from the lung. Successful treatment with VATS was carried out in 4 patients, but the procedure needed to be changed to a thoracotomy in 2 patients - in one because of difficulty in single-lung ventilation, and in the other, due to a persistent air leak. Thus, we conclude that giant bulla without any associated severe respiratory failure can be an indication for VATS.

Adult↗
PubMed1996

Marked enlargement of the jaws in secondary hyperparathyroidism--a case report.

A case of facial deformity and malocclusion due to secondary hyperparathyroidism is presented. Treatment consisted of parathyroidectomy, followed by recontouring of the maxilla and mandible with additional dental treatment. A 3-D reconstruction of the computed tomography (CT) scan was helpful in evaluating the facial deformities and in treatment planning.

Adult↗
PubMed1996

Changes in fibre types in rat soleus and plantaris muscles following hypophysectomy and compensatory overload.

We investigated whether hypophysectomy could modify the change in muscle fibre types caused by compensatory overload. Male Wistar strain rats were assigned to groups of either normal control (NC), hypophysectomized control (HC), normal compensatory overloaded (NO), or hypophysectomized compensatory overloaded (HO). Compensatory overload was induced by the bilateral removal of the gastrocnemius muscle. Five weeks later, there were losses in the soleus and plantaris muscle weights as a result of hypophysectomy. Compensatory overload increased muscle weights independently of the hypophysectomy. Growth hormone and 3,5,3'-triiodothyronine levels were significantly decreased following hypophysectomy. In the soleus, hypophysectomy increased the percentage of type I fibres at the expense of type IIA fibres. Compensatory overload decreased type IIA fibres under the hypophysectomized condition. In the plantaris, the percentage of type IIC fibres was increased at the expense of both type IIA and IIB fibres following hypophysectomy. The decrease in type IIB fibres cause by compensatory overload was induced irrespective of hypophysectomy. The changes in muscle fibre types in the HO group were equal to the sum of the changes in the HC and NO groups. These results suggest that after a period of 5 weeks hypophysectomy may induced decrease in type IIA and IIB fibres in association with the lack of pituitary and thyroid hormones, and that the hypophysectomy could not modify the change in muscle fibre types caused by compensatory overload.

Aging↗
PubMed1996

Immunologic mechanisms in common rheumatologic diseases.

Rheumatoid arthritis and seronegative spondyloarthropathies are rheumatologic diseases that likely are caused by inflammatory reactions occurring in genetically predisposed individuals mounting an immune response to the antigen. Understanding the immunopathology of these diseases provides insight into their etiology, pathogenesis, and a rationale for therapies targeting immune component interactions. Although the antigen in rheumatoid arthritis is not known, several bacterial antigens have been associated with seronegative spondyloarthropathies. These antigens result in an interaction between the human leukocyte antigen-B27 restricted CD8 positive T lymphocytes and the antigen presenting cell, producing an inflammatory response. Rheumatoid factors are autoantibodies directed against the fragment crystallizable portion of the immunoglobulin G. Rheumatoid factor immunoglobulin G immune complexes contribute to the inflammatory events in the rheumatoid joint, and may play an important role in antigen presentation. A novel antigen capture enzyme linked immunosorbent assay was developed that mimicked B cell surface expressed rheumatoid factor. Conversely, a direct binding enzyme linked immunosorbent assay mimicked secreted rheumatoid factor. Comparison of rheumatoid binding enzyme linked immunosorbent assays showed that the physical state of rheumatoid factor can affect binding characteristics. The state of glycosylation of immunoglobulin G may contribute to its antigenic structure. These physical characteristics may be important in rheumatoid factor's pathogenic role in rheumatoid arthritis.

Antigens, CD↗
PubMed1996

A novel neutralization epitope on the 'thumb' subdomain of human immunodeficiency virus type 1 reverse transcriptase revealed by a monoclonal antibody.

We have prepared a MAb, 7C4, which inhibits the RNA-dependent DNA polymerase activity of human immunodeficiency virus type 1 (HIV- 1) reverse transcriptase (RT); this MAb has allowed identification of a previously unknown neutralizing epitope of RT. Analysis of the epitope and of the mechanism of polymerase inhibition revealed that 7C4 acts by interfering with the interaction between RT and the template-primer. 7C4 recognizes a discontinuous epitope on the two alpha-helices, alphaH and alpha(I), that make up the 'thumb' subdomain of RT. The existing crystallographic model of HIV-1 RT suggests that the 'thumb' subdomain, together with the 'fingers' and 'palm', form a nucleic-acid-binding cleft in the 66 kDa subunit of RT and that alphaH is in contact with the primer strand of the template-primer. The extent of inhibition of enzyme activity produced by 7C4 correlates with the reported primer-length-dependency of template-primer binding to RT. Inhibition by 7C4 was competitive with respect to the template-primer and mixed with respect to the substrate. Binding of 7C4 to RT was prevented by preincubation of the enzyme with high concentrations of template-primer but not with substrate. Thus, the 7C4 epitope apparently exists on part of the template-primer binding site of the alphaH and alpha(I) regions of the 'thumb' subdomain. This neutralization epitope is a logical target for the development of new types of HIV-1 RT inhibitors.

Animals↗
PubMed1996

Clinical significance and time course of antibodies to glutamic acid decarboxylase in Japanese children with type I (insulin-dependent) diabetes mellitus.

Although anti-glutamic acid decarboxylase antibodies (GADAb) have been reported to be a useful diagnostic and predictive marker of insulin-dependent diabetes mellitus (IDDM, type 1 DM) in Caucasians, a precise analysis of GADAb in Japanese children has not been reported. We examined the clinical significance and time course of GADAb in Japanese IDDM children, who have different genetic backgrounds from Caucasians. Twenty-three of 34 (67.6%) sera from recent-onset (< 6 months) IDDM, and 16 of 49 (32.7%) sera from long-standing (> or = 2 years) IDDM patients were positive for GADAb. This prevalence of GADAb in IDDM patients was significantly higher than in normal controls and the other groups including non-insulin-dependent DM, autoimmune thyroid disease and congenital hypothyroidism, and was also significantly higher in recent-onset than in long-standing IDDM. Time course analysis suggested that autoimmune response against GAD could follow different courses in individual cases after the initiation of insulin therapy. The incidence of GADAb was significantly higher in females than in males in the older age group (11-15 years). Other clinical features including residual pancreatic beta-cell function after diagnosis were demonstrated to be similar between GADAb-positive and -negative patients. In conclusion, this study using the newly established radioimmunoassay (RIA) for GADAb revealed a high prevalence of autoimmune reactivity to GAD in Japanese IDDM children. These results, using this RIA procedure, might assist in laying the groundwork for future trials of immunomodulation therapy for IDDM in Japan.

Adolescent↗
PubMed1996

cGMP produced in response to ANP and CNP regulates proliferation and differentiation of osteoblastic cells.

The effects of natriuretic peptides on the proliferation and differentiation of osteoblast-like cells from rat calvariae were examined. Natriuretic peptides are physiological agonists that activate receptor guanylate cyclases, namely, natriuretic peptide receptor (NPR)-A and NPR-B. Exposure of cells to atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) resulted in large increases in the rate of intracellular production of guanosine 3',5'-cyclic monophosphate (cGMP). Moreover, CNP-like immunoreactivity was detected in the conditioned medium from osteoblast-like cells, while ANP was undetectable. In cells exposed to natriuretic peptides, a dose-dependent reduction in the rate of DNA synthesis was observed. Natriuretic peptides also stimulated the activity of alkaline phosphatase (ALPase) and the expression of mRNA for ALPase and osteocalcin and the mineralization of nodules by the cultured cells. These results could be reproduced by treating cells with 8-bromo-cGMP. Endothelin-1, whose physiological functions are the opposite of those of natriuretic peptides, decreased the ALPase activity and the mineralization of nodules. In the present study, natriuretic peptides were demonstrated to promote bone formation via the action of cGMP in a signal-transduction pathway mediated by specific receptors in osteoblast-like cells.

Alkaline Phosphatase↗
PubMed1996

Expression of a CD44 variant containing exons 8 to 10 is a useful independent factor for the prediction of prognosis in colorectal cancer patients.

PURPOSE: To determine the expression of the CD44 variant containing a variant exon 8 to 10 product (CD44v8-10) in colorectal cancer and to evaluate its prognostic value. MATERIALS AND METHODS: CD44v8-10 was studied in resected tumors and normal mucosae obtained from 215 colorectal cancer patients (118 colon cancer and 97 rectal cancer). The expression of CD44v8-10 was analyzed immunohistochemically using the anti-CD44v8-10 monoclonal antibody (mAb) 44-1V. RESULTS: One hundred of 215 cancer tissues expressed CD44v8-10. Positive staining was intense mainly on the cell membranes. There was no significant correlation between expression of CD44v8-10 and histologic type, primary tumor, lymphatic invasion, venous invasion, or peritoneal invasion. There were significant correlations between CD44v8-10 immunoreactivity and both lymph node and hematogenous metastasis. Patients with CD44v8-10-positive tumors had a greater relative risk of death compared with those whose tumors were CD44v8-10-negative. Among 169 patients who underwent curative resection, CD44v8-10 expression correlated with a high recurrence rate. The 5- and 10-year survival rates were 90.3% of patients with CD44v8-10-negative tumors, and 72.1% and 58.0% of those with CD44v8-10-positive tumors, respectively; these differences between the two groups of patients were significant (P < .01). In multivariate analysis using the Cox regression model, CD44v8-10 expression emerged as an independent prognostic indicator. CONCLUSION: The results suggest that CD44v8-10 plays a role in metastasis of colorectal cancer, and tha CD44v8-10 expression may be a biologic marker of prognostic significance.

Antibodies, Monoclonal↗
PubMed1996

An estrogen deficiency caused by ovariectomy increases plasma levels of systemic factors that stimulate proliferation and differentiation of osteoblasts in rats.

To investigate the pathogenesis of accelerated bone formation in estrogen deficiency, diffusion chambers containing osteoblast-like cells isolated from newborn rat calvariae were transplanted into the peritoneal cavity of sham-operated (sham), ovariectomized (OVX) rats, and OVX rats with supplement of 17 beta-estradiol (OVX + E2). Bone formation in the diffusion chambers transplanted into OVX rats was more accelerated than that transplanted into sham rats and OVX + E2 rats. Osteoblast-like cells cultured with the sera isolated from OVX rats exhibited higher levels of the DNA content in the culture wells, alkaline phosphatase activity, messenger RNA expression for alkaline phosphatase and osteocalcin, calcium content in the cell layer, and formation of bone-like nodules than those exposed to the sera from sham rats and OVX + E2 rats. Antibody against IGF-I almost completely inhibited the increase in DNA contents induced by the sera isolated from OVX rats but partially inhibited alkaline phosphatase activity. Adding IGF-I to the sera isolated from sham rats increased the DNA content to the same extent as that induced by the supplement with the sera from OVX rats but did not increase alkaline phosphatase activity appreciably. Addition of various concentrations of 17 beta-estradiol, interleukin (IL)-1, and IL-6 to the sera isolated from sham rats did not increase the DNA content or alkaline phosphatase activity in the osteoblast-like cells. These results indicate that some systemic factor(s) other than IGF-I, IL-1, and IL-6 may be responsible for the stimulative effect on osteoblast differentiation in the pathogenesis of the accelerated bone formation induced by estrogen deficiency in rats.

Alkaline Phosphatase↗
PubMed1996

Protective effects of Acanthopanax senticosus Harms from Hokkaido and its components on gastric ulcer in restrained cold water stressed rats.

The aim of this study is to investigate the pharmacological effect of the stem bark of Acanthopanax senticosus Harms from Hokkaido (Japanese name: Ezoukogi) in place of the root bark as a restorative tonic on the stress-induced gastric ulcer. In the test, the extract of the stem bark of A. senticosus prepared with hot water was dissolved in water and used for the assay of the protective effect of gastric ulcer (erosion) on stressed rats that were restrained on cold water. The result from a single oral administration of the stem bark of A. senticosus-extract (50, 100 and 500 mg/kg, per day) dissolved in 1 ml distilled water did not show any protective effect on gastric ulcer, but the protective effect was observed in a dose-dependent manner from the oral administration of the extract (50, 100 and 500 mg/kg, per day) for 2 weeks. Pre-administration of the stem bark of A. senticosus-extract in a dose of 500 mg/kg showed the most potent inhibition without affecting either body or adrenal glands weights. Among ether, chloroform, n-butanol and aqueous residue extracts from the stem bark of A. senticosus-extract, the n-butanol extract used for oral administration for 2 weeks showed an obvious inhibition of 61.1% on gastric ulcer, compared with the control group which was treated with distilled water in the same way. Chlorogenic acid and syringaresinol di-o-beta-D-glucoside, as the major components of the n-butanol extract, showed a significantly inhibitory effect on gastric ulcer, at 21.4% and 51.3%, respectively. We suggested that the protective effect of the stem bark of A. senticosus on gastric ulcer may be partially due to those of chlorogenic acid and syringaresinol di-o-beta-D-glucoside.

Adrenal Glands↗
PubMed1996

Extracellular processing of bone and dentin proteins in matrix mineralization.

There are two steps in the process of matrix-mediated bone and dentin mineralization. First, as in other soft tissues, osteoblasts/odontoblasts synthesize collagenous matrices and second, mineral deposits in these matrices at a location distant from the cells that synthesized the matrices. We suggest a sequence of events that lead the matrix to mineralization: the phosphoproteins of bone and dentin are posttranslationally processed by limited proteolysis, then they are extracellularly processed into a more phosphorylated species that, we believe, facilitates mineralization. Our in situ phosphorylation experiments done with [gamma-32P] GTP suggest the existence of extracellular phosphorylation by a casein kinase II (CKII)-like enzyme, the enzyme known to phosphorylate most of the phosphate residues in dentin phosphophoryn and bone sialoproteins (osteopontin and BSP II).

Adenosine Triphosphatases↗
PubMed1996

[The availability of personality traits in the hierarchical structure: an exploration of the "basic level"].

Personality traits have a structure that is hierarchically organized in terms of trait abstractness. Which level of the hierarchy is most available to the person perceiver? We started out with four levels, and tried to determine which was most available and therefore became the "basic level", as in the Rosch, Mervis, Gray, Johnson, and Boyes-Braem's natural categories (1976). Two methods were employed. First, rating of trait descriptiveness showed that information effectiveness was relatively high at the second level from the top. Second, subjects preferred the same level when they described target persons. These results suggested that a "basic level" indeed existed in the hierarchy of personality traits. However, social desirability of traits and who the target person was also affected the results. Implications are discussed about theories of cognitive style, especially cognitive complexity, which assume the generality of our cognitive system and have been in confusion with contradictory findings.

Adult↗
PubMed1996

An unusual coccidian parasite causing pneumonia in a northern cardinal (Cardinalis cardinalis).

In June 1993 an unusual coccidian parasite was identified in lung tissue from a northern cardinal (Cardinalis cardinalis), collected near Tucson, Arizona (USA), which died in respiratory distress. Histologically, there was evidence of severe, generalized interstitial pneumonia, associated with the parasite. Both asexual and sexual stages were seen. Schizonts, gamonts, and sporulated oocysts were seen in lung tissue. The parasite most closely resembled coccidia of the genus Lankesterella. This is the first report of such a coccidian parasite in the alveolar tissue of a cardinal.

Animals↗
PubMed1996

[Evaluation of preoperative chemotherapy for colorectal cancer].

Patients who underwent curative resection for colorectal cancer between January 1987 and June 1989 were divided into two groups, to assess the usefulness of preoperative chemotherapy (400 mg UFT therapy daily for 10 days more) and to analyze changes in the proliferative activity of tumor cells. Fifty-five cases were included in the study. Thirty-three had received no preoperative chemotherapy (Group A), and 22 had received the preoperative chemotherapy (group B). The five-year cumulative survival rate was 81.1% for group A and 90.2% for Group B. The proportion of patients with no recurrence was 75.7% in Group A and 85.7% in Group B. Both parameters thus tended to be better in patients who had received preoperative chemotherapy. When PCNA labeling before UFT therapy was compared with that after UFT therapy in 13 cases, the PCNA labeling rate decreased after UFT therapy in 9 (69%) of the 13 cases. These results suggest that preoperative chemotherapy using UFT is useful in treating colorectal cancer, and that the proliferative activity of colorectal cancer can sometimes be reduced by such preoperative adjuvant therapy.

Administration, Oral↗
PubMed1996

[Prospective randomized trial comparing 1/2 FAM (5-fluorouracil (5-FU) + adriamycin + mitomycin C) versus palliative therapy for the treatment of unresectable pancreatic and biliary tract carcinomas (the 2nd trial in non-resectable patients). Japanese Study Group of Surgical Adjuvant Therapy for Carcinomas of the Pancreas and Biliary Tract].

The efficacy of 1/2 FAM, which consists of 5-fluorouracil (5-FU), adriamycin (ADM) and mitomycin C (MMC), was compared with that of palliative treatment in patients with unresectable pancreatic and biliary tract carcinomas in a multicenter randomized trial. The patients assigned to 1/2 FAM group were treated with 5-FU 200 mg/m2/day IV, ADM 15 mg/m2/day IV and MMC 5 mg/m2/day IV. These 3 drugs were given concurrently as the initial dose within a week after palliative operation, and this regimen was repeated for at least 2 whole courses, at 4-week intervals before the next course of therapy. Those randomized to the control group were subjected to palliative treatment alone. Completely eligible for analysis were 42 cases of the 1/2 FAM group and 41 of the control group. There was no significant difference between the groups with respect to the overall and differentiated survival times according to the tumor sites and the clinical efficacy. As for the duration of 50% inhibition of tumor progression, a significantly better outcome was obtained in 1/2 FAM group. Tumor progression was most significantly inhibited in patients with gallbladder carcinoma. In 1/2 FAM group, tumor reduction was achieved in 1 CR and 2 PR patients. The most frequent adverse reaction was gastrointestinal manifestations, along with diarrhea and alopecia. 1/2 FAM did not contribute to the life prolongation, but inhibited the tumor progression for a significantly longer duration and, to a lesser extent, reduced the tumor size in unresectable pancreatic and biliary tract carcinomas. This regimen is suggested to be useful particularly in the treatment of the latter carcinoma.

Adult↗