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Biomedical subjects

H Tsuda

Publications and source records attributed to H Tsuda.

At least 415 records · Page 23Linked to original sources
PubMed1992

Immunohistochemical localization of hepatocyte growth factor protein in pancreas islet A-cells of man and rats.

Hepatocyte growth factor (HGF), a potent mitogen for adult rat hepatocytes in primary culture, has previously been shown to be primarily expressed in the nonparenchymal cells of the liver. Using polyclonal antisera against human and rat HGFs we studied the tissue distribution of HGF immunohistochemically and found the most intense staining in the pancreas islet cells in both man (autopsy cases) and the rat. Differential localization of 4 pancreas islet hormones, glucagon, insulin, somatostatin and pancreatic polypeptide, revealed HGF to be preferentially expressed within the glucagon-positive cells. The results indicate that HGF is primarily produced or stored in A-cells and may act as a growth factor in a paracrine and an endocrine fashion, like various other hormones.

Animals↗
PubMed1992

Immunoadsorbent plasmapheresis for a patient with antiphospholipid syndrome during pregnancy.

The case of a 34 year old woman with systemic lupus erythematosus with a history of three previous recurrent abortions and lupus anticoagulant and anticardiolipin antibodies is reported. Immunoadsorbent plasmapheresis with a dextran sulphate column was used to remove lupus anticoagulant, anticardiolipin antibodies, and antibodies to DNA during her fourth pregnancy in combination with low doses of aspirin and prednisolone. Although during the course of treatment prednisolone was transiently increased to 30 mg/day owing to an asymptomatic increase of lupus anticoagulant and anticardiolipin antibodies, the levels of lupus anticoagulant, anticardiolipin antibodies, and antibodies to DNA were decreased by immunoadsorbent plasmapheresis and a baby girl was delivered successfully by caesarean section. Therefore, immunoadsorbent plasmapheresis with dextran sulphate seems to reduce the risk of recurrent abortion in patients with the antiphospholipid syndrome.

Adult↗
PubMed1992

Deficiency of coagulation factor XIII A subunit caused by the dinucleotide deletion at the 5' end of exon III.

A congenital deficiency of the coagulation Factor XIII A subunit (F XIII A) is a rare autosomal recessive disorder that is characterized by a life-long bleeding tendency complicated by a difficulty in healing. Thus far, no molecular genetic analysis of this disorder has been reported. In this study, we demonstrate the molecular abnormalities in a family with this disorder. We performed Northern blot analysis of peripheral blood monocytes obtained from the propositus and found a 4-kb single band of F XIII A mRNA whose size was identical with that of normal subjects. Exons II-XV, which encode all the amino acids, were individually amplified by a polymerase chain reaction (PCR). All PCR products from the propositus had lengths indistinguishable from those of the wild type on agarose gel, suggesting that this defect results from either a point mutation or a short deletion/insertion. The sequencing of F XIII A cDNA from the propositus revealed a deletion of the dinucleotide AG within the AGAG repeat at the position of 210 to 213. Concerning the genomic sequence, a deletion of dinucleotide AG was also demonstrated in the intron B-exon III boundary. This deletion appeared to cause a frameshift mutation making a new stop codon shortly thereafter, and leading to a deficiency of plasma F XIII A. The heterozygosity of the F XIII A deficiency in the patient's offspring was documented by the nucleotide sequences of their exon III.

Alleles↗
PubMed1992

Importance of hydrolysis of amino acid moiety in water-soluble prodrugs of disodium cromoglycate for increased oral bioavailability.

The relationship between physicochemical properties and oral absorption was investigated in prodrugs for the oral delivery of disodium cromoglycate (DSCG). To improve the lipophilicity of DSCG, various lipophilic moieties were introduced into the twin carboxyl groups. However, this did not lead to improved oral absorption in rabbits because of loss of water solubility, in spite of improved lipophilicity. Water-soluble prodrugs, in which an amino acid was introduced into a hydroxy group by ester linkage in addition to ethyl residues at twin carboxyl groups of DSCG, were synthesized and examined for oral absorption in rabbits and rats. The oral absorption of these prodrugs was affected by the species of amino acids introduced as a water-soluble moiety. Therefore, we examined the relation between the oral absorption of water-soluble prodrugs and the hydrolysis rate of the amino acid moiety. A good linear correlation was obtained between the oral absorption and the hydrolysis rate constant catalyzed by digestive enzymes, trypsin or alpha-chymotrypsin. It was thus concluded that the amino acid moiety of water-soluble prodrugs must be rapidly hydrolyzed to a permeable lipophilic prodrug still possessing the ethyl moiety at twin carboxyl groups in the small intestinal tract for good oral absorption.

Administration, Oral↗
PubMed1992

Immunohistochemical study of c-erbB-2 oncoprotein overexpression in human major salivary gland carcinoma: an indicator of aggressiveness.

In order to analyze the correlation between immunohistochemical positivity for c-erbB-2 oncoprotein and prognosis in patients with malignant salivary gland tumors, 59 cases of malignant tumors of the major salivary glands, including 35 parotid gland, 20 submaxillary gland and 4 sublingual gland tumors, were studied immunohistochemically using a polyclonal antibody against c-erbB-2 oncoprotein. Positive staining was observed in 13 (22%) of the 59 cases. Interestingly, positive results were obtained only in adenocarcinoma (6/20) and carcinoma in pleomorphic adenoma (7/15), and not in any other histological types such as adenoid cystic carcinoma, mucoepidermoid tumor, and squamous cell carcinoma. There was no correlation between the degree of differentiation of adenocarcinoma and c-erbB-2 positivity. Since the carcinoma in pleomorphic adenoma positive for c-erbB-2 oncoprotein was adenocarcinoma, adenocarcinoma and adenocarcinoma in pleomorphic adenoma were placed together (n = 33), and the presence or absence of c-erbB-2 oncoprotein in this group was examined for correlation with patients' survival and other clinicopathological features, including clinical stage, tumor size, surgical margins, and lymph node status. The c-erbB-2-positive tumors tended to be more advanced and larger than negative tumors. Similarly, c-erbB-2-positive tumors were difficult to resect completely, were associated with lymph node metastasis more frequently, and showed lower disease-free survival than negative cases (P less than .05). We conclude that immunohistochemical positivity for c-erbB-2 is an indicator of aggressiveness in both adenocarcinoma and adenocarcinoma in pleomorphic adenoma of the major salivary glands.

Adenocarcinoma↗
PubMed1992

Prognostic factors for recurrent breast cancer: univariate and multivariate analyses including histologic grade and amplification of the c-erbB-2 proto-oncogene.

Post-recurrence survival was examined in 62 breast cancer patients who had undergone curative radical mastectomies between 1974 and 1976 and suffered recurrences within 127 months of surgery. The prognostic value of 11 clinical, histological and genetic factors, including histologic grade of malignancy and amplification of oncogenes was analyzed using univariate and multivariate analyses. Not only the site of first recurrence, clinical stage and size of primary tumor at initial surgery, and disease-free period, but also histologic grade and amplification of the c-erbB-2 proto-oncogene were significant prognostic indicators of recurrent breast cancer. Multivariate analysis using Cox's regression model, histologic grade and amplification of c-erbB-2 in the primary tumor, as well as clinical stage at surgery and site of first recurrence, were shown to be major independent prognostic factors of recurrent breast cancer. Because post-recurrence prognosis was strongly influenced by the clinical, histological and genetic status of the primary breast cancer, appropriate evaluation of the primary tumor for the grade of aggressiveness of the cancer cells, as well as the extent of cancer spread, seem to be important.

Biomarkers, Tumor↗
PubMed1992

Studies on the outcome of lupus nephritis according to long-term treatment employing different modes of immunotherapy.

The outcome of long-term treatment of lupus nephritis under different immunotherapies, together with the factors affecting the outcome of lupus nephritis, was studied. A total of 212 lupus nephritis patients were classified into 5 groups according to their different modes of treatment: (1) initial dose of prednisolone (PSL) below 39 mg/day, (2) initial dose of PSL above 40 mg/day, (3) pulse therapy and steroids, (4) steroids and immunosuppressants, and (5) combination therapy of plasmapheresis with other therapies. The outcome of lupus nephritis was evaluated into 5 grades. As a result, the complete remission rate of lupus nephritis was 9.4%. The 5-year survival rates increased with all modes of treatment. However, it was impossible to identify which mode of therapy could bring about the highest rate of remission. Decreases in extrarenal involvement and low complement levels were observed together with increases in IgM anti-DNA antibodies among the lupus nephritis patients with remission.

Adolescent↗
PubMed1992

Possible mechanisms for the elevation of serum beta 2-microglobulin levels in adult T-cell leukemia.

In our previous study, we found that serum beta 2-microglobulin (beta 2M) levels were elevated in the active, but not in the inactive, phase of adult T-cell leukemia (ATL), suggesting a correlation between the beta 2M level and the clinical severity of this disease. In this study we examined the mechanisms underlying the elevation of serum beta 2M levels in ATL. First, the production of beta 2M by ATL cells was investigated in vitro. High levels of beta 2M were detected in the conditioned culture medium (CM) of ATL cells from seven out of nine patients. Second, we assessed the effects of the CM on the release of beta 2M by three human cell lines unrelated to ATL (NCTC 2544, Chang liver, and L 132; originating from the skin, the liver, and the fetal lung, respectively). Most of the CM definitely promoted beta 2M production by these cell lines. beta 2M production by the cell lines was markedly promoted by exogenous interferon-gamma (IFN-gamma), a well-known potent inducer of class I HLA antigen expression. We then investigated whether an antibody directed against IFN-gamma could attenuate the activity of three ATL CM. The anti-IFN-gamma antibody reduced the stimulatory activity of the CM to 28-65% of the original level, but did not affect basal beta 2M production by these cell lines. These data suggest that there are at least two mechanisms causing the elevation of serum beta 2M levels in ATL; direct production by tumor cells, and production by non-malignant cells that is mediated via humoral factors secreted by the ATL cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Rapid protein tyrosine phosphorylation selectively induced in murine responsive ELM-I-1 cells by erythropoietin.

We investigated whether protein tyrosine phosphorylation was induced by erythropoietin (Epo) in two murine Epo-responsive cell lines (ELM-I-1, which proliferates autonomously and is induced to differentiate by Epo, and DA-1ER, which grows in a manner dependent on Epo or interleukin-3 (IL-3) without differentiation). In ELM-I-1, Epo induced the tyrosine phosphorylation of a protein of about 80-85 kDa (py80) which appeared in the Triton-X soluble fraction of the cell lysate in a time- and concentration-dependent manner. Maximal levels of phosphorylation were obtained within 5-10 min at Epo concentrations above 0.1 U/ml. IL-3 is known to promote the proliferation of this cell line, but it did not induce py80 phosphorylation. In DA-1ER, tyrosine phosphorylation of py80 was not induced by either Epo or IL-3. These findings suggest that there are multiple pathways of Epo signaling and that one of them could be via tyrosine kinase activation. Furthermore, it is possible that the tyrosine phosphorylation of py80 is involved in the pathway leading only to erythroid differentiation but not to cellular proliferation.

Animals↗
PubMed1992

[Plasmapheresis for patients with RA].

Effect of plasmapheresis for patients with rheumatoid arthritis. Plasmapheresis for rheumatoid arthritis (RA) was performed more than ten years, but efficacy of plasmapheresis was not done. In this paper, we discussed efficacy, indications and procedures. We have many procedures of plasmapheresis, 1) plasma exchange, 2) double filtration plasmapheresis, 3) cryofiltration plasmapheresis, 4) immunoadsorption plasmapheresis, 5) salt-amino acid coprecipitation plasmapheresis, 6) lymphocytapheresis, 7) lymphocyte-plasmapheresis, 8) photopheresis. Indications of plasmapheresis for RA are 1) malignant RA, 2) high activity of RA, 3) positive circulating immune complexes, 4) patients can't take steroid hormone or anti-inflammatory drugs. Efficacy of plasmapheresis for RA was not done, then, we must have controlled study about efficacy of plasmapheresis for RA.

Arthritis, Rheumatoid↗
PubMed1991

Alteration of nuclear proto-oncogene expression by erythropoietin (Epo) in Epo-responsive murine cell lines.

The signal transduction system of erythropoietin (Epo) and the accompanying molecular control mechanism of proliferation and differentiation of erythroid progenitors remains largely unknown. In this study, the effect of Epo on the expression of nuclear oncogenes was investigated in two murine cell lines which respond to the hormone in different ways: ELM-I-1 cells proliferate independently of Epo, but differentiate in response to the hormone, while the growth of DA-1ER cells is absolutely dependent on Epo or interleukin (IL) 3. The cell lines were stimulated with Epo or IL-3, and total RNA was extracted. Then expression of nuclear proto-oncogenes (c-myc, c-fos and c-myb) was analyzed by northern blotting. The change in c-fos expression observed during the first two h following stimulation with either stimulant were common to both cell lines; a rapid and temporary increment. Before stimulation, c-myc and c-myb were strongly expressed in both lines. No apparent change in c-myc expression was observed during the first two h of stimulation, while c-myb expression in ELM-I-1 cells was slightly reduced 1 h after stimulation with Epo but not with IL-3. Three days after stimulation with Epo, but not with IL-3, only ELM-I-1 produced hemoglobin and expressed a lower amount of c-myb mRNA. These data suggest the importance of c-fos in the early signaling system of Epo, and the involvement of c-myb in erythroid differentiation but not in proliferation.

Animals↗
PubMed1991

The prognostic value of tumor-associated carbohydrate structures correlated with gene amplifications in human breast carcinomas.

The effects of cell surface sugar chains combined with certain gene amplifications of breast cancers on the prognosis of patients were studied and the relationships between the sugar chains of cancer cells and amplifications of the proto-oncogenes c-myc, int-2 and c-erb B-2, evaluated. One hundred and fifty three human breast carcinoma tissues were investigated by an immunohistochemical technique using the avidinbiotin-peroxidase method with 1 lectin (HPA; Helix Pomatia) and 4 monoclonal antibodies (B-72-3, St-439, anti-Tn and anti-T). The positive rates of HPA, St-439, B-72-3, anti-Tn and anti-T were 43 per cent (63/153), 52 per cent (80/153), 53 per cent (81/153), 64 per cent (98/153) and 89 per cent (136/153), respectively. Patients whose cancers had positive HPA staining were found to have a lower survival rate than those with negative HPA staining (p less than 0.05), whereas those whose cancers had positive St-439 staining showed a better prognosis than those with negative St-439 staining (p less than 0.01). The positive rate of HPA was related to the gene amplification of c-myc proto-oncogene (p less than 0.01), whereas the negative rate of St-439 was correlated with the gene amplification of c-erb B-2 (p less than 0.01). These data indicate the prognostic value of HPA and St-439 and also the relationships between the gene amplifications and carbohydrate structures in breast cancer cells.

Antibodies, Monoclonal↗
PubMed1991

Marked increases in DT diaphorase activity in malignantly transformed Syrian hamster fibroblastic cells.

NAD(P)H quinone oxidoreductase (DT diaphorase; EC 1.6.99.2) activity in cultured Syrian hamster fibroblastic cells was measured. The cells examined were classified into three categories: (1) four primary embryonic fibroblasts, (2) three non-malignant immortal cells and (3) four malignantly transformed cells. The results showed that cytosolic DT diaphorase activity in malignant cells was markedly higher than the corresponding activity in non-malignant cells (enzyme activity: (3) much greater than (1) greater than or equal to (2)). The enzyme activity was not influenced very much by the particular phase of cell growth. Thus, the increase in DT diaphorase activity seems to be a good marker for malignant transformation, at least in Syrian hamster fibroblastic cells.

Animals↗
PubMed1991

Association of NMDA receptor sites and seizures of El mice.

To investigate the possible role of N-methyl-D-aspartate (NMDA) receptors in the seizures of El mice, a genetic animal model of epilepsy, we measured [3H]3-[(+)-2-(carboxypiperazin-4-yl)][1,2-3H]- propyl-1-phosphonic acid (CPP) binding in several brain regions of El and ddY mice. At 22-24 weeks of age, the maximum number of binding sites (Bmax) of [3H]CPP was lower only in the cerebral cortex of both stimulated and unstimulated El mice (El(+) and El(-), respectively) than in that of ddY mice. A reduction in Bmax values of cortical [3H]CPP binding of El mice was detected after the age of 12 weeks. Cortical [3H]CPP binding in El(+) mice decreased further transiently after evoked seizures. No significant change was observed in El(-) mice after postural stimulation. These results suggest that El(+) and El(-) mice share seizure propensity and that activation of NMDA receptors is involved in the seizures of El mice.

Aging↗
PubMed1991

Enhancing potential of 6 different carcinogens on multi-organ tumorigenesis after initial treatment with N-methyl-N-nitrosourea in rats.

The advantages of applying a whole-body concept to the assessment of carcinogenic potential of compounds in a two-stage model after initiation by N-methyl-N-nitrosourea (MNU) were investigated. Male, 6-week-old F344 rats were injected with MNU (20 mg/kg, i.p.) twice a week for 4 weeks and they then received 3,2'-dimethyl-4-aminobiphenyl (DMAB) (50 mg/kg, s.c., once a week), N,N'-dibutylnitrosamine (DBN) (0.05%, in drinking water), N-bis(2-hydroxypropyl)nitrosamine (DHPN) (0.1%, in drinking water), diethylstilbestrol (DES) (2.5 ppm, in diet), sodium o-phenylphenate (S.OPP) (2%, in diet) or captafol (0.15%, in diet) for 20 weeks. All six carcinogens enhanced the incidences of preneoplastic and neoplastic lesions in their respective target organs: liver, pancreas, small intestine and urinary bladder with DMAB; liver, esophagus, forestomach and urinary bladder with DBN; thyroid, lung, liver, esophagus, forestomach, small intestine and urinary bladder with DHPN; liver and forestomach with DES; and thyroid, forestomach, kidney and urinary bladder with S.OPP; liver and forestomach with captafol. The results suggested that prior treatment with MNU sensitized the tissues to the organotropic carcinogenic potential of chemicals given thereafter for as short a period as 20 weeks. Thus, this system could be utilized as a whole-body medium-term bioassay system for the screening of environmental carcinogens, bridging the gap between in vitro mutagenicity and long-term carcinogenicity tests.

Animals↗
PubMed1991

Point mutation of c-Ki-ras oncogene in gastric adenoma and adenocarcinoma with tubular differentiation.

The presence of point mutation at codons 12, 13 and 61 of the c-Ki-ras oncogene was investigated in 7 cases of gastric adenoma and 35 cases of gastric adenocarcinoma using DNA samples from formalin-fixed and paraffin-embedded tissues. Oligonucleotides encompassing the three codons were amplified by using the polymerase chain reaction (PCR), and then examined for point mutation by the selective oligonucleotide hybridization technique. Point mutation was detected in three of the 7 adenomas (43%) and three of the 35 carcinomas (9%). All the gastric adenomas showed the histology of tubular adenoma, being very similar to that of colonic adenoma. The 35 cases of gastric adenocarcinoma were classified into 17 cases of differentiated type and 18 cases of undifferentiated type including signet-ring cell carcinoma. The point mutation of c-Ki-ras oncogene was detected only in the differentiated type (3/17, 18%), and there was no case with point mutation in the undifferentiated type. These results suggest that the genetic mechanism of carcinogenesis differs between the differentiated type and the undifferentiated type of gastric adenocarcinoma, and also that c-Ki-ras activation is possibly involved in a relatively early step of the "adenoma-carcinoma sequence," which leads to the development of a portion of differentiated adenocarcinomas in the stomach.

Adenocarcinoma↗