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Biomedical subjects

S Yamada

Publications and source records attributed to S Yamada.

At least 883 records · Page 49Linked to original sources
PubMed1994

Growth hormone and prolactin gene expression in human densely and sparsely granulated somatotroph adenomas by in situ hybridization with digoxigenin-labeled probes.

We studied growth hormone (GH) and prolactin (PRL) messenger ribonucleic acids (mRNAs) in 14 cases with densely granulated somatotroph (DG) adenomas and 10 cases with sparsely granulated somatotroph (SG) adenomas using in situ hybridization with digoxigenin-labeled probes and correlated these data with their immunohistochemical results. A good correlation between in situ hybridization results and immunohistochemical data was found in most cases examined. The DG adenomas generally had a diffuse and intense GH immunoreactivity and GH hybridization signal, whereas in SG adenomas the number of cells exhibiting a GH mRNA signal and the strength of the GH mRNA signal in these cells were relatively lower than those of DG adenomas, indicating that lower expression of the GH mRNA signal is responsible for lower GH production in SG adenomas. In addition, PRL mRNA expression differed in the two types of adenoma; in DG adenomas, seven cases (50%) expressed PRL mRNA signal with a focal or scattered distribution despite normal serum PRL levels, but two showed no PRL immunoreactivity. In contrast, in SG adenomas, only one case contained a few cells possessing a PRL mRNA signal despite having no PRL immunoreactivity. It can be concluded that DG and SG adenomas, which have been considered variants of the same tumor, display definite differences as to GH or PRL gene expression in each type of adenoma.

Adenoma↗
PubMed1994

Comparative study on alpha 1-adrenoceptor antagonist binding in human prostate and aorta.

1. Specific binding of [3H]-prazosin in prostatic and aortic membranes of humans was saturable and of high affinity (prostate: apparent dissociation constant, Kd = 0.35 +/- 0.03 nmol/L; aorta: Kd = 0.26 +/- 0.03 nmol/L). The density of [3H]-prazosin binding sites (Bmax) for prostate and aorta was 546 +/- 31 and 61.6 +/- 1.6 fmol/mg protein, respectively. 2. Prazosin, YM617, naftopidil and urapidil competed with [3H]-prazosin for the binding sites in a dose-dependent manner in the prostate and aorta of humans. The binding affinities of these antagonists in both tissues were compared, based on the inhibition constant, Ki. Both prazosin and urapidil showed similar affinity to [3H]-prazosin binding sites in human tissue, whereas YM617 and naftopidil showed approximately a 12 and two times higher affinity, respectively, to alpha 1-adrenoceptor sites of prostate than aorta. 3. The chloroethylclonidine treatment reduced partially the Bmax values for specific [3H]-prazosin binding in the prostate and aorta of humans with little effect on the Kd values. 4. These data suggest that YM617 is a relatively selective antagonist of human prostatic alpha 1-adrenoceptors.

Adrenergic alpha-Antagonists↗
PubMed1994

Histologic and immunohistochemical study of clinically non-functioning pituitary adenomas: special reference to gonadotropin-positive adenomas.

Seventy-five clinically non-functioning pituitary adenomas were characterized in terms of their histologic and immunohistochemical features. Fourteen adenomas (18.7%) were positive for hormones other than gonadotropins. These included two somatotroph adenomas, three lactotroph adenomas, four thyrotroph adenomas, four corticotroph adenomas and one unusual plurihormonal adenoma. Fifty-five adenomas (73.3%) were exclusively positive for one or more gonadotropin subunits (beta-follicle stimulating hormone, beta-luteinizing hormone, and alpha-subunit of glycoprotein hormones), but negative for other hormones such as growth hormone and beta-thyrotropin. Histologically, a papillary arrangement along the capillary was most characteristically observed in the gonadotropin-positive adenomas. Five of six adenomas negative for any pituitary hormones exhibited the typical papillary structure. Thus, approximately 80% of clinically non-functioning adenomas constituted a single tumor group that shared the common histologic features of gonadotroph adenomas. These findings suggest that nearly all tumor types of clinically non-functioning adenomas can be diagnosed solely by light microscopy in combination with immunohistochemistry, and that the vast majority of them may be gonadotroph adenomas.

Adenoma↗
PubMed1994

Infection by Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, and antibody responses at different ages in humans.

This study examined the serum IgG and IgM responses against Porphyromonas gingivalis and 3 serotypes of Actinobacillus actinomycetemcomitans, and the correlations of these responses with age and homologous infection. A total of 90 individuals were included in this study: 40 subjects with gingivitis, 40 periodontally healthy subjects, and 10 adult periodontitis subjects. The subjects in the gingivitis and periodontally healthy groups were divided into 4 stages based on their physiological age: early childhood, school age, puberty, and adult. In the gingivitis group, there was a positive correlation between increase in age and increase in serum IgG antibody levels against P. gingivalis until puberty. However, no statistically significant difference was found between the puberty stage and the adult stage. The average level of IgG antibodies against A. actinomycetemcomitans in the school age gingivitis group was significantly higher than that in the early childhood gingivitis group for all serotypes (p < 0.01). In serotype c, IgG antibody levels in the school age gingivitis group were significantly higher than in the early childhood gingivitis group or the adult gingivitis group (p < 0.01). With both P. gingivalis and A. actinomycetemcomitans, positive correlations between elevated IgG level and infections by these microorganisms were found in the puberty gingivitis and adult periodontitis groups.

Adolescent↗
PubMed1994

[A child with iritis due to Chlamydia pneumoniae infection].

A case of uncommon iritis due to Chlamydia pneumoniae (C. pneumoniae) is reported. The patient was a 9-year-old boy who had suffered from cough, pharyngeal pain, and low grade fever. The symptoms persisted for more than 1 month in spite of an oral cephem antibiotic. Ophthalmalgia, congestion around the iris and cough had lasted with alleviation and exacerbation. A diagnosis of C. pneumoniae infection was made by specific polymerase chain reaction (PCR) method and microimmunofluorescence test (MIF). The symptoms subsided with administration of clarithromycin (CAM: 300 mg/day) for 2 weeks. Because of the simultaneous alleviation of iritis, C. pneumoniae infection was considered to introduce the iritis. Much remains to be clarified about this pathogenesis of iritis and more detailed evaluations are required.

Child↗
PubMed1994

[Shigella boydii strains having a provisional serovar isolated from travellers' diarrhea in Tokyo].

Two Shigella strains (85-634 and 94-30) isolated from two sporadic travellers with diarrhea who returning to Tokyo from abroad, did not react to any antisera to Shigella prepared commercially. These strains had the typical biochemical characteristics of S. boydii and were biochemically identical, and were positive in the Serény test and other tests for invasiveness; these indicate that they can cause shigellosis in humans. The results of serological analyses using the antisera to 6 kinds of provisional Shigella serovars, showed that both strains had provisional S. boydii serovar E16553. Although the serovar has been reported by Gross et al in the United Kingdom, this may be the first report in Japan.

Child↗
PubMed1994

Serodiagnosis by passive hemagglutination test and verotoxin enzyme-linked immunosorbent assay of toxin-producing Escherichia coli infections in patients with hemolytic-uremic syndrome.

Eight cases of hemolytic-uremic syndrome in which no pathogens were isolated were diagnosed serologically by a passive hemagglutination assay and a verotoxin (VT; Shiga-like toxin) enzyme-linked immunosorbent assay (ELISA). The passive hemagglutination assay employed formalinized sheep erythrocytes sensitized with soluble native antigen or heat-treated antigen (lipopolysaccharide [LPS]) from Escherichia coli O26, O111, O128, and O157 or flagellar antigen of nine different H serogroups of E. coli: H2, H7, H8, H10, H11, H12, H18, H19, and H25. All patients had antibodies against the native antigen and/or the LPS of E. coli O157, but positive agglutination with H7 was observed only in one patient. In the VT-ELISA with plates coated with purified VT 1 or VT 2, antibody against VT 2 was observed in the sera of five of six patients examined, but none of the patients possessed VT 1 antibody. These results indicate that the causative pathogen in these eight hemolytic-uremic syndrome cases is likely to be VT-producing E. coli O157. The passive hemagglutination assay described here is a very sensitive, simple, and rapid method. This assay is highly recommended for the serological diagnosis of VT-producing E. coli infections, particularly in patients infected by serogroup O157 strains. Furthermore, the VT-ELISA is useful in studying the role of VT in hemolytic-uremic syndrome.

Animals↗
PubMed1994

Erythrocytosis complicated by multiple paraganglioma.

We report the case of a 22-year-old woman with onset of erythrocytosis at the age of 9 years. Endocrinological and radiological examinations revealed an elevated catecholamine level and the presence of multiple abdominal tumors. After the removal of the tumors, the catecholamine level normalized, whereas erythropoietin remained at the same level and erythrocytosis persisted. The tumor lysate contained considerable amounts of catecholamine but not erythropoietin. Moreover, no erythropoietin mRNA was detected in the tumor by in situ hybridization. These data suggest that this paraganglioma did not produce erythropoietin. A review of the literature showed the existence of patients with early-onset erythrocytosis complicated with paraganglioma, whose erythrocytosis was not relieved even after the resection of paraganglioma.

Abdominal Neoplasms↗
PubMed1994

Extracorporeal shock wave lithotripsy using the Dornier MPL 9000 lithotriptor.

336 patients with urinary calculi were treated between June 1988 and October 1991 with extracorporeal shock wave lithotripsy using the Dornier MPL 9000 lithotriptor. Of 352 renal units (a kidney and its ureter), 286 had renal stones, 62 had ureteral stones and 10 had both. There were radiolucent stones in 6 units. The complete disintegration rate was 94%. The mean number of shock waves was 2,973, the range being from 300 to 16,131. In 310 of 447 (64%) sessions, treatment was done without any anesthesia. The rate of complete removal was 67.3% 3 months after the last treatment. Only 11 patients required supplementary treatment consisting of percutaneous nephrolithotripsy and transurethral lithotripsy. There were no severe complications except subcapsular hematomas observed in 2 patients. The Dornier MPL 9000 is a useful lithotriptor for the treatment of urinary calculi, except staghorn calculi.

Female↗
PubMed1994

Elevated biopterin and homovanillic acid levels in cerebrospinal fluid from children with aseptic meningitis.

To examine biopterin fractions and biogenic amine metabolites in cerebrospinal fluid in aseptic meningitis, the concentrations of homovanillic acid, 5-hydroxyindoleacetic acid, and the total, the oxidized form, and the reduced form of biopterin were determined in cerebrospinal fluid specimens from 15 children with aseptic meningitis in the acute phase, 15 children with aseptic meningitis in the recovery phase, and six other children as controls. The concentration of each substance was significantly higher in the acute phase than in the recovery phase. Homovanillic acid in the acute phase was significantly increased compared to that in the control group. The concentrations of the total, the oxidized form, and the reduced form of biopterin, and 5-hydroxyindoleacetic acid were higher in the acute phase than those in the controls; however, the differences were not significant. The concentration of each substance in the recovery phase was not significantly different from that in the controls. There was no difference in the 5-hydroxyindoleacetic acid/homovanillic acid ratio or in the reduced form/total biopterin ratio among the patients in acute and recovery phases and the controls. These results suggested that levels of biopterin and biogenic amine metabolites in cerebrospinal fluid are increased in the acute phase of aseptic meningitis and return to normal during the recovery phase. This is the first report of increased concentrations of biopterin fractions and biogenic amine metabolites in aseptic meningitis.

Biopterins↗
PubMed1994

Localization of cyclic adenosine 3',5'-monophosphate-responsive element (CRE)-binding proteins by southwestern histochemistry.

Regulation of gene transcription requires an interaction between specific segments of nuclear DNA and specific proteins. We describe a method to localize the specific DNA-binding proteins using haptenized double-stranded (ds) DNAs. To demonstrate this method, an oligodeoxynucleotide (oligo-DNA) with a consensus base sequence of cyclic adenosine monophosphate-responsive element (CRE) (TGACGTCA) with three TTA repeats at the 5' end was synthesized. Since the CRE sequence is palindromic, the oligo-DNA was allowed to self-anneal and form ds DNA with three TTA repeats at both ends. The CRE ds-oligo-DNA was irradiated with UV light to form haptenic thymine-thymine (T-T) dimers. The haptenized CRE ds-oligo-DNA reacted by Southwestern analysis with a distinct set of proteins, previously identified as CRE-binding proteins, ranging from 40-90 KD. When the haptenized CRE ds-oligo-DNA reacted with frozen sections fixed with 4% paraformaldehyde in PBS (pH 7.4) followed by enzyme immunohistochemical localization of the T-T dimers, nuclei of intestinal epithelial cells and brain cells were heavily stained. Nuclear staining was blocked when the sections were reacted with the haptenized CRE ds-oligo-DNA in the presence of an excess amount of non-haptenized CRE ds-oligo-DNA. This method, henceforth referred as Southwestern histochemistry, should be a useful tool to localize proteins that bind to a specific DNA sequence and regulate the transcriptional activity of genes.

Animals↗
PubMed1994

Creutzfeldt-Jakob disease transmitted by a cadaveric dura mater graft.

We report a case of Creutzfeldt-Jakob disease developing in a 31-year-old woman 56 months after she received a cadaveric dura mater graft after the removal of a giant pituitary adenoma. Creutzfeldt-Jakob disease was confirmed by a brain autopsy and the existence of an abnormal isoform of prion protein, verified by both immunohistochemical and Western blot analysis. Moreover, prion protein gene analysis was shown in this case to possess a wild-type genotype. The characteristics of Creutzfeldt-Jakob disease after a cadaveric dura mater graft are reviewed and discussed.

Adenoma↗
PubMed1994

Gigantism in sibling unrelated to multiple endocrine neoplasia: case report.

The cases of gigantism sisters with somatotroph adenomas unrelated to multiple endocrine neoplasia (MEN) Type 1 are reported. The sisters grew rapidly since they were 5 or 6 years old and were diagnosed to have gigantism with pituitary adenoma by computed tomographic scan and magnetic resonance imaging. A serum endocrinological examination showed the elevated growth hormone values. After thyroxine-releasing hormone stimulation, growth hormone values exhibited a paradoxical rise. They were supposed to be unrelated to MEN Type 1, because analysis of the 11th chromosomes and the other endocrine functions were normal. They were operated on by the transphenoidal method. Immunohistochemical staining of both tumor specimens confirmed somatotroph adenomas. Pituitary adenoma associated with MEN Type 1 is a well-recognized entity. However, the sporadic occurrence of pituitary adenoma unrelated to MEN Type 1, especially in siblings, is extremely rare. Fifteen cases of pituitary adenomas in siblings were described in the literature. As for gigantism, only two brothers were reported. Our case of gigantism sisters is the second sporadic case. In our review of the isolated cases of pituitary adenoma in siblings described in the literature, 12 (70%) of 17 cases including ours are acromegaly or gigantism. This incidence is much higher than that of MEN Type 1 patients with pituitary adenomas. The cause of the familial occurrence of pituitary adenomas is still unclear, although autosomal recessive inheritance has been suggested. It has been stated that point mutations in codon 201 or 227 of the Gs alpha gene located in chromosome 20 were found in about 35 to 40% of somatotroph adenomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1994

Synthesis and antiulcer activities of novel 2-[(6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-9-yl)sulfinyl]-1H- benzimidazole analogues.

A synthetic study on a series of benzimidazole derivatives including cycloalka[b]pyridine moiety has been carried out. Among these compounds synthesized, a novel antipeptic agent with 6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridine moiety (TY-11345) was found to be superior to omeprazole in (H+ + K+)-ATPase inhibitory activity and antisecretory potencies.

Animals↗
PubMed1994

Effects of strontium on calcium metabolism in rats. I. A distinction between the pharmacological and toxic doses.

Strontium at low doses has been used to treat osteoporosis. However, excessive doses can disturb calcium metabolism. The aim of the present study was to determine a dose that does not have any significant toxic effects on calcium contents in bone and calcium metabolism, and, consequently, to distinguish between pharmacological and toxic doses in rats. The rats were divided into a control, 0.05%-Sr, 0.10%-Sr and 0.50%-Sr groups (strontium intake approx. 0, 87.5, 175 and 875 mumol/day, respectively). All of the rats were pair-fed their respective diets containing various doses of strontium in single metabolic cages from when they were 36 to 63 days old. When the rats were 60 days old, bone formation, bone resorption, calcium balance and intestinal calcium absorption were calculated as calcium metabolic parameters over a 3-day period using calcium balance and kinetic studies. At the age of 64 days, the rats were sacrificed under anesthesia, and the femur and blood were collected. Calcium and strontium levels in the bone and serum were then measured. In the strontium groups that received less than 175 mumol/day, none of the calcium metabolic parameters were significantly affected. However, the calcium contents in the bone were significantly increased in the group that received 87.5 mumol/day group. On the other hand, in the group that received the highest dose of strontium (875 mumol/day), all of the calcium metabolic parameters measured were markedly suppressed. A decrease in calcium level in both the bone and serum was also observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The role of cell-mediated immunity in chickens inoculated with the cell-associated vaccine of attenuated infectious laryngotracheitis virus.

The cell-mediated immune responses of the chickens inoculated with the cell-associated (CA) ILT vaccine were studied. Lymphocyte blastogenic response was tested by MTT assay with spleen, thymus, bursa of Fabricius and peripheral blood lymphocytes of the vaccinated chickens. The blastogenic response of peripheral blood and spleen lymphocytes was enhanced by a T-cell mitogen. The CA vaccine induced an immunity satisfactorily in bursectomized chickens. To study the role of immune cells in the vaccinated chickens, the bursectomized chickens were inoculated intravenously with the splenic, thymic, bursal and peripheral blood lymphocytes of the vaccinated chickens. Protective effects were shown in the chickens received the splenic cells and peripheral blood lymphocytes, indicating that these play an important role in eliciting the protective effects of the CA vaccine. From these results, it was found that the immune mechanism with CA vaccine against ILT involves mainly cell-mediated immunity.

Animals↗
PubMed1994

Isolation of porcine reproductive and respiratory syndrome (PRRS) virus from Heko-Heko disease of pigs.

Porcine reproductive and respiratory syndrome (PRRS) virus was isolated at high frequency from the sera and lungs of pigs affected with Heko-Heko disease. In addition, a considerable amount of Mycoplasma hyorhinis (Mhr) was also isolated from the lungs. Inoculation of gnotobiote pigs with the first isolate of PRRS virus resulted in the reproduction of proliferative and interstitial pneumonia. The virus was recovered from the inoculated pigs for long periods. Superinfection with PRRS virus and Mhr appeared to produce more serious pneumonia than inoculation with PRRS virus alone. In this study, the presence of PRRS virus was confirmed in Japan, and the PRRS virus was considered as being the most important pathogen for Heko-Heko disease.

Animals↗