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Biomedical subjects

S Harada

Publications and source records attributed to S Harada.

At least 199 records · Page 11Linked to original sources
PubMed1998

[Diagnostic usefulness of the tuberculin reaction by PPD-B in Mycobacterium avium complex disease].

This study was carried out to clarify the diagnostic usefulness of the skin tests of purified protein derivatives from M. intracellulare (PPD-B) and M. tuberculosis (PPDs). Study subjects consisted of 41 patients with primary infection type of M. avium complex (MAC) disease, 36 patients with pulmonary tuberculosis (TB) and 29 patients with other bacterial respiratory infections including COPD (OB). The patients were sorted out to middle (50-69 y.o.) and old (70-89 y.o.) age groups of each disease. The size of skin redness elicited 48 hours after the PPD-B and PPDs intradermal injections were compared among them. The results were as follows. 1) Both PPD-B and PPDs skin reactions were larger in the middle age group than in the old one for each disease. 2) In PPDs skin tests, the reaction of TB group was the largest among the three diseases. In PPD-B skin tests, that of MAC was the largest. 3) In TB group, PPDs skin reaction was significantly larger than that of PPD-B, while in MAC and OB groups there was no significant difference between the skin reactions of PPDs and PPD-B. 4) Defining significant positive reaction to PPD-B as PPD-B skin reaction exceeding 10 mm and larger than that of PPDs skin reaction, the rate of significant positive reaction to PPD-B was significantly higher in MAC than TB in both age groups. These results showed that the simultaneous skin tests of PPD-B and PPDs were a useful aid in the diagnosis of MAC infection disease when mycobacterial infection diseases were clinically suspected by bacteriological or chest radiographic examinations.

Age Factors↗
PubMed1998

Tissue factor and tissue factor pathway inhibitor in hemodialysis patients.

Tissue factor and tissue factor pathway inhibitor are important in extrinsic coagulation. We investigated their clinical significance in hemodialysis patients. We took blood samples, prior to initiation of routine hemodialysis, from 73 patients on hemodialysis (35 men and 38 women aged 56.1+/-11.7 years on dialysis for 82.1+/-61.0 months), and determined tissue factor and tissue factor pathway inhibitor levels by ELISA. In the patients the tissue factor level was 704.5+/-141.6 pg/ml and the tissue factor pathway inhibitor level was 44.5+/-23.3 ng/ml; both values were significantly higher than in normal controls (192.7+/-36.6 pg/ml and 18.6+/-5.7 ng/ml, respectively). In patients with shunt obstruction, tissue factor pathway inhibitor levels were significantly higher than in those without it. Therefore, the tissue factor pathway inhibitor level may be a marker of shunt obstruction.

Adult↗
PubMed1997

Lack of infectivity of HIV-1 integrase zinc finger-like domain mutant with morphologically normal maturation.

The integrase (IN) encoded by human immunodeficiency virus type-1 (HIV-1) is required for integration of the viral DNA into a host cell chromosome. The function of the highly conserved HHCC motif in the HIV-1 IN amino-terminal zinc finger-like domain is still unknown. In this study, we examined the effect of mutations in the HHCC motif on viral infectivity, adsorption to and entry into target cells, and morphology in the context of a full-length form of an HIV-1 molecular clone. A complete lack of infectivity and de novo synthesized viral DNA of the HHCC mutants were demonstrated in both cell-free and co-culture infection systems using MT-2 or HeLa-CD4-LTR-beta-gal as target cells. The levels of viral adsorption to and entry into the target cells were determined by measuring the cell-associated p24 level in target MT-2 cells shortly after infection. We detected comparable cell-associated p24 levels of MT-2 cells after infection with wild-type and the mutant viruses. Taken together, these results suggest that the replication of HIV-1 carrying point mutations in the HHCC motif was blocked at the step after adsorption/ entry and prior to the initiation of reverse transcription, presumably at the uncoating step. Furthermore, electron microscopy revealed that the observed complete lack of viral infectivity caused by introducing an amino acid substitution into the HHCC motif is not always accompanied by apparent abnormal morphology or maturation of virus particles.

Adsorption↗
PubMed1997

Subarachnoid hemorrhage induces c-fos, c-jun and hsp70 mRNA expression in rat brain.

To detect stress responses of the brain to subarachnoid hemorrhage (SAH), we investigated the expression of immediate early genes (IEGs) and hsp70 mRNA by in situ hybridization. Experimental SAH was produced in 49 rats by endovascular penetration. We also monitored the intracranial pressure (ICP) changes. The genes c-fos and c-jun were induced in the cerebral cortex, hippocampus and dentate gyrus in the penetrated side. mRNA coding for hsp70 was induced in the cerebral cortex, hippocampus, thalamus, hypothalamus and caudoputamen in the penetrated side and extended to the contralateral hemisphere. IEGs in the cerebral cortex were completely blocked by MK-801 pretreatment, but hsp70 mRNA was not. This suggests that the expression of IEGs correlates with spreading depression. The IEGs and hsp70 expression may reflect the severity of SAH impact and relate to the mechanisms of symptomatic vasospasm.

Animals↗
PubMed1997

Inhibition of rheumatoid synovial fibroblast proliferation by antisense oligonucleotides targeting proliferating cell nuclear antigen messenger RNA.

OBJECTIVE: To evaluate the feasibility of antisense oligonucleotides as therapeutic agents to inhibit synovial cell growth in rheumatoid arthritis (RA). METHODS: Fibroblast-like cells established from RA synovium were stimulated with interleukin-1beta (IL-1beta) and treated with antisense or sense oligonucleotides targeting proliferating cell nuclear antigen (PCNA) messenger RNA (mRNA). Proliferation of these cells was determined by 3H-thymidine incorporation. Effects of antisense oligonucleotides on the expression of mRNA and protein were evaluated by reverse transcriptase-polymerase chain reaction and immunohistochemical staining, respectively. RESULTS: Antisense oligonucleotides targeting PCNA inhibited IL-1-stimulated fibroblast proliferation, whereas sense oligonucleotides had no effect. Both mRNA and protein levels of PCNA were suppressed in the cells treated with antisense oligonucleotides, indicating that the antiproliferative effect was occurring through an antisense mechanism. CONCLUSION: These results suggest that antisense strategies designed to suppress PCNA expression have potential use as therapeutic agents for RA.

Arthritis, Rheumatoid↗
PubMed1997

The synovial expression and serum levels of interleukin-6, interleukin-11, leukemia inhibitory factor, and oncostatin M in rheumatoid arthritis.

OBJECTIVE: To determine the expression of interleukin-6 (IL-6), IL-11, leukemia inhibitory factor (LIF), and oncostatin M (OSM) and their major cellular sources in the joints of rheumatoid arthritis (RA) patients, as well as the correlation of circulating levels of these IL-6-type cytokines and C-reactive protein (CRP). METHODS: Messenger RNA (mRNA) and protein levels for IL-6, IL-11, LIF, and OSM were determined by using reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. RESULTS: Cells isolated from the synovium of RA patients expressed mRNA for IL-6, IL-11, LIF, and OSM at higher levels than did synovial cells from osteoarthritis (OA) patients, and spontaneously released greater quantities of these proteins in culture. Fibroblast cell lines derived from RA synovium were able to produce IL-6, IL-11, and LIF, but not OSM, when stimulated with IL-1 and tumor necrosis factor alpha. OSM was found to be produced spontaneously by synovial tissue macrophages. IL-6, IL-11, LIF, and OSM were present in synovial fluid from the RA patients; levels of IL-6, LIF, and OSM were present in significantly greater quantities in RA patients than in OA patients. However, only IL-6 was significantly elevated in the serum of RA patients and correlated with the serum CRP level, while other IL-6-type cytokines were not detected. CONCLUSION: IL-6, IL-11, LIF, and OSM are all produced in large amounts at the site of disease activity, but IL-6 derived from synovial fibroblasts may be the major hormone-like mediator that induces the hepatic synthesis of acute-phase proteins in RA.

Adult↗
PubMed1997

Cervical cord ependymoma with numerous microrosettes.

"Microrosette ependymoma," which is ependymoma with numerous microrosettes throughout the tumor, has rarely been reported. We describe an autopsy case of cervical cord ependymoma with two unusual features: the presence of numerous microrosettes and the formation of trabecular architecture. The tumor originated in the C2 segment of a man aged 23 years and gradually expanded over the following 15 years and 10 months until the entire cervical cord was involved. Beside the low grade of malignancy, the tumor cells exhibited a strong tendency to form microrosettes and trabecular architecture, which formed many perivascular pseudorosettes. The microrosettes mostly consisted of only two or a few more cells, in the absence of large rosettes. Thus the constituent cells were those forming perivascular pseudorosettes. Electron microscopy and immunohistochemistry characterized the ependymal properties of the microrosettes, whose lumina frequently contained fibril bundles similar to those of the Reissner's fiber fibrils, in addition to cilia and microvilli. The pathogenesis of the occurrence of numerous microrosettes is unknown; however, a defect in the mechanism of regulation of rosette formation and enlargement is the most likely explanation.

Adult↗
PubMed1997

Insulin internalization and other signaling pathways in the pleiotropic effects of insulin.

Insulin is the major anabolic hormone in humans and affects multiple cellular processes. Insulin rapidly regulates short-term effects on carbohydrate, lipid, and protein metabolism and is also a potent growth factor controlling cell proliferation and differentiation. The metabolic and growth-related effects require insulin binding to its receptor and receptor phosphorylation. Evidence suggests these events result in subsequent substrate phosphorylation and activation of multiple signaling pathways involving Src homology domain-containing proteins and the internalization of the insulin:receptor complex. The role of insulin internalization in insulin action is largely speculative. For more than two decades, extensive investigation has been carried out by numerous laboratories of the mechanisms by which insulin causes its pleiotropic responses and the cellular processing of insulin receptors. This chapter reviews our current knowledge of the phosphorylation signaling pathways activated by insulin and presents evidence that substrates other than insulin receptor substrate-1 are involved in insulin's regulation of immediate-early gene expression. We also review the mechanisms involved in insulin internalization and present evidence that internalization may play a key role in insulin action through both signal transduction processes and translocation of insulin to the cell cytoplasm and nucleus.

Animals↗
PubMed1997

Incidence of actinic keratosis of Japanese in Kasai City, Hyogo.

We determined the incidence of actinic keratosis (AK) among Japanese by screening for skin cancer in Kasai City, Hyogo, Japan, between 1993 and 1995. The incidence per 100,000 Japanese residents was 223.6 in 1993 and 171.2 in 1994. The prevalence of AK was 291.2 per 100,000 residents in 1993, 203.7 in 1994, and 86.8 in 1995. The prevalence in people who had more than six seborrheic keratoses on sun-exposed body sites and in people who had experienced severe sunburns with blister formation during childhood were significantly higher. These results indicate that more than six seborrheic keratoses and several episodes of blister formation in childhood may be risk factors for AK in the Japanese.

Adult↗
PubMed1997

Prevalence of actinic keratosis in Japan.

Most of the epidemiological studies on skin cancer that have been conducted to date have addressed the incidence in light-skinned Caucasians. To determine the prevalence rate of skin cancer and actinic keratosis (AK) on sun-exposed body sites of Japanese in Japan, we examined the skin of 4736 people during health examinations. The study was undertaken in Kasai City, Japan, which had a population of 52,837 in 1992, where participants in a regional health examination were seen by dermatologists. The final diagnosis was made histopathologically. Participants were also interviewed by means of a questionnaire. A total of 36 cases of AK and two of basal cell carcinoma were identified, to give a prevalence of 413.4 per 100,000 for AK. The prevalence among outdoor workers was significantly higher than that of indoor workers. Furthermore, when the participants were classified into three Japanese skin types, the prevalence of AK among people of skin Type I, who are sensitive to UV irradiation, was significantly higher than that among people of skin Types II and III, who are less sensitive.

Adult↗
PubMed1997

Enhanced radioresponse of paclitaxel-sensitive and -resistant tumours in vivo.

Paclitaxel is a potent chemotherapeutic drug and also has the potential to act as a radioenhancing agent. The latter is based on its ability to arrest cells in the radiosensitive G2M phases of the cell cycle; the weight of supporting evidence is derived mainly from in vitro studies. Our previous in vivo experiments identified enhanced tumour radioresponse predominantly attributable to tumour reoxygenation occurring as a result of paclitaxel-induced apoptosis. The current study investigated whether paclitaxel enhanced the radioresponse of tumours which are insensitive to apoptosis induction, but exhibited mitotic arrest, and compared the degree and kinetics of the response to that in tumours which develop apoptosis. The mouse mammary carcinoma MCa-29 (apoptosis sensitive) and the squamous cell carcinoma SCC-VII (apoptosis resistant) were used. In addition, the study investigated whether paclitaxel affected normal skin radioresponse to determine if a therapeutic gain could be achieved. Paclitaxel enhanced the radioresponse of both types of tumours. In the SCC-VII tumour, radiopotentiation occurred within 12 h of paclitaxel administration coincident with mitotic arrest, where enhancement factors (EFs) ranged from 1.15 to 1.37. In MCa-29 tumour, the effect was greater, EFs ranging from 1.59 to 1.91 and occurred between 24 and 72 h after paclitaxel when apoptosis was the predominant microscopic feature of treated tumours and when tumour oxygenation was found to be increased. The acute skin radioresponse and late leg contracture response were essentially unaffected by prior treatment with paclitaxel. Therefore, by two distinct mechanisms, paclitaxel was able to enhance the radioresponse of paclitaxel-sensitive and -resistant tumours, but not the normal tissue radioresponse, thus providing true therapeutic gain.

Animals↗
PubMed1997

Different characteristics of gustatory responses between the greater superficial petrosal and chorda tympani nerves in the rat.

The integrated responses to gustatory stimuli applied to the soft palate were recorded from the greater superficial petrosal nerve (GSP) and were compared with those from the chorda tympani nerve (CT) innervating the anterior part of the tongue in the rat. Stimuli included various concentrations of NaCl, sucrose, HCl and quinine hydrochloride, and 0.5 M of six sugars. The inhibitory effects of amiloride on the responses to sodium salts, including various concentration of NaCl, 0.1 M sodium acetate and 0.01 M sodium saccharin, were also tested. Both the phasic and tonic responses to sugars in the GSP were significantly larger than those in the CT, whereas both responses to NaCl in the GSP were significantly smaller than those in the CT. Although amiloride at 50 microM significantly depressed the phasic and tonic responses to NaCl with a wide range of concentration in the CT, little inhibitory effect was observed in the GSP. The tonic response to sodium acetate, when dissolved in amiloride solution, was depressed to 15% of the control in the CT, and slightly but significantly depressed to 70% in the GSP. These response characteristics of the GSP may play important roles in the processing of gustatory information.

Amiloride↗
PubMed1997

Structure of the zinc endoprotease from Streptomyces caespitosus.

A zinc endoprotease produced by Streptomyces caespitosus (ScNP) specifically hydrolyzes the peptide bond at the imino side of aromatic residues and is the smallest protease found to date. Although ScNP carries the zinc-binding sequence HEXXH, its primary structure of 132 amino acid residues differs from those of other known zinc metalloendoproteases. X-ray structural analysis of ScNP at 1.6 A resolution revealed that despite a lack of sequence homology, the common topological feature of main-chain folding and a beta-turn containing methionine, which is a feature of the zinc metalloendoprotease superfamily of metzincins, is conserved in ScNP. The zinc atom of ScNP is tetrahedrally ligated by the two histidines in the HEXXH sequence, an aspartate residue and a water molecule. Thus, ScNP represents a novel subfamily of metzincins with a HEXXHXXGXXD zinc-binding sequence. A plausible substrate recognition pocket to which aromatic residues bind is located near the catalytic zinc ion.

Amino Acid Sequence↗
PubMed1997

Clonality in nevocellular nevus and melanoma: an expression-based clonality analysis at the X-linked genes by polymerase chain reaction.

The true nature of nevocellular nevus is still unknown and it has been ambiguously classified as a neoplasm or a hamartoma. We studied the clonality of nevocellular nevus and melanoma (malignant melanoma), using an expression-based clonality analysis at the X-linked genes by means of polymerase chain reaction. DNA was extracted from cryostat sections of 20 nevocellular nevi (10 compound and 10 intradermal type) and five melanomas from female patients. A polymorphic portion of the inactivated X-linked gene was amplified after selective digestion of the active X-chromosome with a methylation-sensitive restriction enzyme, Hpa II. Paternal- and maternal-derived fragments were resolved with electrophoresis using the polymorphic restriction endonuclease (BstX I) site for the phosphoglycerate kinase assay, and using the difference of CAG repeats for the human androgen-receptor gene assay. Both assays revealed that all informative nevocellular nevi were polyclonal in origin and all melanomas were monoclonal. Results of the clonality were independent of either the histologic type of nevocellular nevus or whether the nevocellular nevus was of congenital or acquired origin. Thus, nevocellular nevus, congenital or acquired, may be a hamartomatous rather than a neoplastic lesion. The analysis of clonality could be applied to the differential diagnosis of benign melanocytic disease and melanomas.

Adolescent↗
PubMed1997

Abrogation of in vitro suppression of human immunodeficiency virus type 1 (HIV-1) replication mediated by CD8+ T lymphocytes of asymptomatic HIV-1 carriers by staphylococcal enterotoxin B and phorbol esters through induction of tumor necrosis factor alpha.

CD8+ T lymphocytes of asymptomatic human immunodeficiency virus type 1 (HIV-1) carriers (AC) suppress HIV-1 replication in vitro. Failure of host defense mechanisms and increased virus proliferation are associated with disease progression. The exact mechanisms inducing these changes at the advanced stage of the disease are still obscure. In this study, we searched for experimental conditions favoring the abrogation of the suppression of viral replication in peripheral blood mononuclear cells (PBMC) of AC by using various pharmacological and biological probes modifying cell activation. Among such agents, staphylococcal enterotoxin B (SEB) and phorbol 12-myristate 13-acetate (PMA) markedly increased otherwise low levels of HIV-1 replication in cultures of phytohemagglutinin-stimulated AC PBMC following in vitro HIV-1 LAI infection. A similar but less pronounced virus induction was also observed in macrophage-tropic HIV-1. Individual pretreatment of CD4+ and CD8+ PBMC fractions with these agents caused a reduction in CD8+ cell proliferation and enhanced HIV-1 replication in CD4+ cells. SEB- and PMA-mediated augmentation of HIV-1 replication in AC PBMC was significantly blocked by neutralizing antibody to tumor necrosis factor-alpha (TNF-alpha), although recombinant TNF-alpha alone failed to reproduce the effects of SEB or PMA. Our results suggest that the induction of TNF-alpha may be one of the mechanisms that overcomes the CD8+-induced suppression of HIV-1 replication in AC and that it may induce HIV-1 replication.

Antibodies↗
PubMed1997

Epstein-Barr virus nuclear protein LP stimulates EBNA-2 acidic domain-mediated transcriptional activation.

Epstein-Barr virus (EBV) nuclear proteins EBNA-LP and EBNA-2 are the first two proteins expressed in latent infection of primary B lymphocytes. EBNA-2 is essential for lymphocyte transformation, and EBNA-LP is at least critical. While EBNA-2 activates specific viral and cellular promoters, EBNA-LP's role has been obscure. We now show that EBNA-LP stimulates EBNA-2 activation of the LMP1 promoter and of the LMP1/LMP2B bidirectional transcriptional regulatory element. EBNA-LP alone has only a negative effect. EBNA-LP also stimulates EBNA-2 activation of a multimerized regulatory element from the BamC EBNA promoter. Since both viral regulatory elements can bind the EBNA-2-associated cell protein RBPJ kappa, consensus RBPJ kappa binding sites were positioned upstream of the herpes simplex virus type 1 thymidine kinase promoter and were found to be sufficient for EBNA-LP and EBNA-2 coactivation. EBNA-LP strongly stimulated activation of an adenovirus E1b promoter with upstream Gal4 binding sites by a Gal4 DNA binding domain/ EBNA-2 acidic domain fusion protein, indicating that EBNA-LP coactivation requires only the EBNA-2 acidic domain to be localized near a promoter. The EBNA-LP stimulatory activity resides in the amino-terminal 66-amino-acid repeat domain. The carboxyl-terminal unique 45 amino acids appear to regulate EBNA-LP's effects. The first 11 amino acids of the 45 have a strong negative effect, while the last 10 are critical for the ability of the last 34 to relieve the negative effect. These results indicate that EBNA-LP's critical role in EBV-mediated cell growth transformation is in stimulating (and probably regulating) EBNA-2-mediated transcriptional activation.

Binding Sites↗
PubMed1997

The mechanisms of transient hypothyroxinemia in infants born to mothers with Graves' disease.

Transient hypothyroxinemia in infants born to mothers with Graves' disease is a unique disorder first reported by us in 1988. Most mothers of these infants have had no treatment, are diagnosed as having thyrotoxicosis during the last trimester, or were not well controlled during pregnancy. These infants are believed to have transient central hypothyroidism, the mechanisms of which have not been elucidated. We measured TSH-receptor antibody activities in maternal serum and blood thyroxine (T4) (free thyroxine, FT4) and TSH levels in blood dried on filter paper at 1, 3, and 5 d of age in 114 infants born to mothers with Graves' disease. The 114 infants were retrospectively divided into three groups according to the clinical course and thyroid function data: group G, neonatal thyrotoxicosis; group T, transient hypothyroxinemia; and group E, euthyroid. In group T, the dried blood T4 (FT4) level from cord blood and/or 1 d of age blood was 6.0 +/- 2.3 microg/dL (0.92 +/- 0.52 ng/dL), a value significantly higher than that at 5 d of age (3.6 +/- 1.0 microg/dL; 0.38 +/- 0.18 ng/dL) (p = 0.025 in T4, p = 0.042 in FT4). In contrast, these levels were significantly lower at birth relative to 5 d in group G (p = 0.0001 in T4) and not significantly changed in group E. The TSH level of cord blood and/or 1-d-old blood in group T was significantly lower than that of group E (p = 0.0006). Moreover, the TSH levels in response to thyrotropin-releasing hormone were blunted in most infants in group T. Bone maturation was not delayed in group T, compared with euthyroid infants. The higher blood T4 (FT4) levels at birth, relative to 5 d in group T, suggested that the fetal T4 level was higher than that of the newborn period. The fetal T4 level might have been elevated owing to transfer of T4 from mother to fetus during the last trimester when the mother's thyroid function was elevated and consequently the fetal pituitary-thyroid axis was suppressed. Although the serum T4 (FT4) levels were decreased after birth, TSH levels were not elevated, probably because the pituitary-thyroid axis was suppressed. This may be the reason for the transient hypothyroxinemia with a normal TSH level in infants born to mothers with poorly controlled Graves' disease. Weak maternal thyroid-stimulating antibody activities and differences in sensitivity of the thyroid gland to TSH-receptor antibodies may contribute to this unique disorder.

Bone Development↗