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Biomedical subjects

S Yamada

Publications and source records attributed to S Yamada.

At least 757 records · Page 42Linked to original sources
PubMed1995

Diversity of T cell receptor delta-chain cDNA in the thymus of a one-month-old pig.

Pig TCR delta-chain cDNA sequences were obtained from the anchored PCR products of the reverse-transcribed RNA from the thymus of a 1-mo-old germfree pig. Among 43 sequences analyzed, 4 different J delta sequences were found, and in the cDNA sequences of rearranged V-D-J junctional regions, three putative D delta sequences were assigned. Also, the V delta region sequences were grouped into five families. One family, V delta 1, consisted of a large number of members and the other families consisted of limited members as determined by cDNA sequences as well as genomic Southern blots. Using PCR, V delta 1 gene segments were also obtained from liver genomic DNA of the same individual pig. Thirty-one distinct sequences were found for the V delta 1 family including the sequences obtained from both the thymic RNA and the PCR product of liver DNA. All the V delta 1 genes were found to be associated with almost identical leader gene sequences. The amino acid sequences of the complimentarity-determining region 3 coded by the V-D-J joints gave long and variable lengths with a high content of tryptophan and charged amino acids. The length of the complimentarity-determining region 3 in the porcine TCR delta-chain supports the idea that TCR delta-chain is designed to see Ags directly similar to the Ig heavy chain. Data presented from this study shows that the porcine TCR delta-chain has extensive V region diversity as well as junctional diversity. The combination of these two creates a level of diversity that is the highest of any lymphocyte Ag receptor studied so far.

Amino Acid Sequence↗
PubMed1995

Increased 5-HT2 receptor-mediated behavior 11 days after shock in learned helplessness rats.

In the learned helplessness procedure, rats can be differentiated into two distinct groups. Learned helplessness (LH) rats do not learn to escape a controllable shock while non-learned helplessness (NLH) rats learn this response. This deficit in performance in LH rats lasted for 11 days. In LH rats, pretreatment with acute desipramine (15 mg/kg i.p.) or chronic diazepam (0.95 mg/kg/day p.o. for 7 days) did not produce recovery from this deficit of performance, but pretreatment with chronic desipramine (17.7 mg/kg/day p.o. for 7 days) or chronic mianserin (6.1 mg/kg/day p.o. for 7 days) led to recovery. Before presentation of uncontrollable shock, there was no difference between LH and NLH rats, but 11 days after the shock, head shakes induced by (+/-)-1-(2,5-demethoxy-4-iodophenyl)-2-aminopropane (DOI) in LH rats was significantly more frequent than those in NLH and naive rats without change of [3H]ketanserin binding. The basal corticosterone level was higher in LH rats than in NLH rats. These findings suggest that the learned helplessness model is a reliable animal model of depression accompanied by 5-HT2 receptor hypersensitivity.

Animals↗
PubMed1995

Cytokine-producing mammary carcinomas in transgenic rats carrying the pX gene of human T-lymphotropic virus type I.

In two lines of transgenic rats (pX rats) from WKAH and F344 strains and carrying the human T-lymphotropic virus type I pX gene, undifferentiated mammary carcinomas developed predominantly in females starting at about 5 months of age, and there was massive infiltration of granulocytes in the tumor tissue. The incidence of the tumor reached about 40% when the rats were 12 months old. mRNAs of both pX and host genes Gro and MIP-2, which are granulocyte chemoattractants of the interleukin 8 family, were highly expressed in the tumor tissue. Since expression and point mutation of several oncogenes and the antioncogene were not demonstrated, hitherto unidentified novel oncogenic pathways may be transactivated by the pX transgene in these pX rats.

Animals↗
PubMed1995

Induction of hepatic microsomal drug-metabolizing enzymes by methylsulphonyl metabolites of polychlorinated biphenyl congeners in rats.

The effect of methylsulphonyl (MeSO2) metabolites of 2,3',4',5-tetrachlorobiphenyl (tetraCB) (IU-70), 2,2',3',4',5-pentachlorobiphenyl (pentaCB) (IU-87), 2,2',4',5,5'-pentaCB (IU-101) and 2,2',3',4',5,5'-hexachlorobiphenyl (hexaCB) (IU-141), on the hepatic microsomal drug-metabolizing enzyme system was investigated in rats. The administration of 3-MeSO2-2,3',4',5-tetraCB (10 mumol/kg), 3-MeSO2-2,2',3',4',5-pentaCB (0.5 mumol/kg), 3-MeSO2-2,2',4',5,5'-pentaCB (0.5 mumol/kg) and 3-MeSO2-2,2',3',4',5,5'-hexaCB (2 mumol/kg) to rats significantly increased the contents of cytochromes P-450 and b5 and the activities of aminopyrine N-demethylase, 7-ethoxycoumarin O-deethylase and benzo[a]pyrene hydroxylase. From these results, it is suggested that the 3-MeSO2 derivatives studied are possibly potent phenobarbital-like inducers of microsomal drug-metabolizing enzymes. On the other hand, 4-MeSO2-2,3',4',5-tetraCB, 4-MeSO2-2,2',3',4',5-pentaCB, 4-MeSO2-2,2',4',5,5'-pentaCB and 4-MeSO2-2,2',3',4',5,5'-hexaCB had almost no effect on both cytochrome contents and these enzyme activities. After 96 h, following administration of 2,3',4',5-tetraCB, 2,2',3',4',5-pentaCB, 2,2',4',5,5'-pentaCB and 2,2',3',4',5,5'-hexaCB (342 mumol/kg each), significant increases in contents of these two cytochromes and in activities of these enzymes were observed. The relationship between liver concentrations of 3-MeSO2-PCBs after administration of four PCB congeners and that after administration of their 3-MeSO2 derivatives, and increases in the contents of both cytochromes and activities of drug-metabolizing enzyme suggests that the 3-MeSO2 metabolites derived from PCBs studied play an important role in the induction of the drug-metabolizing enzymes by the parent PCB congeners.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1995

Characterization of hepatic microsomal cytochrome P-450 from rats treated with methylsulphonyl metabolites of polychlorinated biphenyl congeners.

The inducing potency of 3-methylsulphonyl(MeSO2)-2,2',4',5,5'-pentachlorobiphenyl (pentaCB), which was one of the major MeSO2 metabolites of polychlorinated biphenyls (PCBs) present in seal blubber, on the hepatic drug metabolizing enzyme activities was examined in comparison with that of the parent compound and phenobarbital (PB). The inducing fashion of the above enzymes and changes in the contents of PB-inducible P-450 forms by 2,3',4',5-tetrachlorobiphenyl (tetraCB) (IU-70), 2,2',3',4',5-pentaCB (IU-87), 2,2',4',5,5'-pentaCB (IU-101) and 2,2',3',4',5,5'-hexachlorobiphenyl (hexaCB) (IU-141), and their MeSO2 metabolites were investigated in rats. Administration at various doses (0.2-1.0 mumol/kg) of 3-MeSO2-2,2',4',5,5'-pentaCB produced nearly dose-related increases in the hepatic concentration of this methyl sulphone, in the contents of cytochromes P-450 and b5, and in activities of aminopyrine N-demethylase, 7-ethoxycoumarin O-deethylase and benzo[a]pyrene hydroxylase of liver microsomes. Major PB-inducible forms, CYP2B1, CYP2B2, CYP3A2 and CYP2C6 were induced with four PCBs (342 mumol/kg) and their 3-MeSO2 metabolites (0.5-10 mumol/kg), indicating that 3-MeSO2 metabolites were strong PB-type inducers of hepatic drug-metabolizing enzymes. 3-MeSO2-2,2',4',5,5'-pentaCB was an especially strong inducer. On the other hand, four PB-inducible forms of cytochrome P-450 were not induced with the 4-MeSO2 isomers. The relation between liver concentrations of the corresponding 3-MeSO2 derivatives and induction of four PB-inducible forms of cytochrome P-450 after administration of four PCBs and their 3-MeSO2 derivatives further confirmed that the 3-MeSO2 metabolites played an important role in the induction which parent PCB congeners caused on the hepatic drug-metabolizing enzyme system.

Animals↗
PubMed1995

Isolation of the porcine heparin tetrasaccharides with glucuronate 2-O-sulfate. Heparinase cleaves glucuronate 2-O-sulfate-containing disaccharides in highly sulfated blocks in heparin.

Eleven tetrasaccharides were isolated from the repeating disaccharide region of porcine intestinal heparin after strong digestion with Flavobacterium heparinase. Their structures were determined by composition analysis, enzymatic analysis, and 1H NMR spectroscopy. Nine of them have the common tetrasaccharide backbone, delta HexA alpha 1-4GlcN alpha 1-4IdoA alpha 1-4GlcN, where delta HexA and IdoA represent 4,5-unsaturated hexuronic acid and L-iduronic acid, respectively, and their structural variations are based upon the positions of sulfate groups. The nine compounds include one hexasulfated, three pentasulfated and five tetrasulfated compounds, and four of them have not been isolated previously as discrete structures. The other two of the 11 tetrasaccharides have the following hitherto unreported structures with novel glucuronate 2-O-sulfate at the internal position: delta HexA(2-sulfate) alpha 1- 4GlcN(N,6-disulfate) alpha 1-4GlcA(2-sulfate) beta 1-4GlcN(N-sulfate) and delta HexA(2-sulfate) alpha 1-4GlcN(N,6-disulfate) alpha 1-4GlcA(2-sulfate) beta 1-4GlcN(N,6-disulfate). Thus, 2-O-sulfated glucuronate in the highly sulfated tetrasaccharide structures typical of heparin has been demonstrated. The former and the latter tetrasaccharides account for 0.31 and 0.32% (w/w) of the starting heparin, respectively. Their yield, however, is an underestimation, since these tetrasaccharide structures in longer sequences will be degraded by heparinase. Although the latter tetrasaccharide described above was unexpectedly cleaved by heparinase into two disaccharide units, the former was not degraded by the enzyme most likely due to the lack of the 6-O-sulfate group on the GlcN residue at the reducing terminus. The results indicate its capability of catalyzing both anti and syn elimination, a property shared by heparitinases I and II and chondroitinase ABC. Both tetrasaccharides were degraded into disaccharides by heparitinase II. Therefore, it is necessary to reevaluate the disaccharide composition of heparin/heparan sulfate or oligosaccharide structures, which were previously determined after heparinase or heparitinase II digestion. It is no longer possible to conclude that the 2-O-sulfated unsaturated uronic acid residues obtained from heparin/heparan sulfate by lyase digestions are always derived from iduronate 2-O-sulfate residues in the original polymer. It is quite possible that the novel glucuronate 2-O-sulfate structure in the highly sulfated region of heparin is involved in some of the biological activities of heparin.

Animals↗
PubMed1995

Biological responses in Caenorhabditis elegans to high magnetic fields.

Here we describe a device for testing possible influences of high magnetic fields on biological processes, by which alternating-current magnetic stimuli as high as 1.7 T can be administered. Experiments with a simple multicellular organism, the nematode Caenorhabditis elegans, revealed that intermittent exposure to the magnetic fields modestly inhibited the animal's reproduction as well as its post-embryonic development, and caused a marked but transient derangement in its locomotory behavior. Available evidence indicates that alternating high magnetic fields can elicit both chronic and acute biological effects, but that the effects may be well tolerated or compensated for by the living organism.

Animals↗
PubMed1995

Cloning and expression of the mouse laminin gamma 2 (B2t) chain, a subunit of epithelial cell laminin.

We have isolated and sequenced the full-length cDNA for the mouse laminin gamma 2 chain and mapped it to mouse Chromosome 1 proximal to laminin gamma 1. The mRNA for the mouse gamma 2 spans 5.2 kb and codes for a 1192-residue amino acid polypeptide. The gamma 2 chain (formerly termed laminin B2t), a homologue of gamma 1 (formerly B2), lacks an N-terminal domain and has a shorter domain III in comparison to the laminin gamma 1 chain. The expression of the laminin gamma 2 and gamma 1 chains in both newborn and fetal mice was examined by both Northern analysis and in situ hybridization. mRNA for the laminin gamma 2 chain was expressed specifically by epithelial cells in many tissues with a particularly high level of expression in the tongue, hair follicles, lung and kidney. In contrast, a high level of expression of the laminin gamma 1 chain mRNA was seen in both epithelial and endothelial cells in these tissues. In addition, gamma 1 mRNA was expressed in other tissues such as the nasal septum, blood vessels, and the muscle of the tongue. Immunohistochemistry with an anti-gamma 2 IgG detected strong expression of the laminin gamma 2 chain in the basement membrane of the collecting tubules of the kidney and of the pancreas. Immunoprecipitation studies with antibodies to the gamma 2 chain detected three species at 165, 155 and 140 kDa in HT-1080 cell-conditioned media. This protein complex is characteristic of the kalinin (nicein/epiligrin) complex, and provides further evidence that these proteins are identical and that the gamma 2 chain is the subunit of the epithelial-cell-specific laminin.

Amino Acid Sequence↗
PubMed1995

Reliable and sensitive method for determination of microcystins in complicated matrices by frit-fast atom bombardment liquid chromatography/mass spectrometry.

A reliable and sensitive method for determination of hepatotoxic microcystins in complicated matrices by frit-fast atom bombardment liquid chromatography/mass spectrometry (Frit-FAB LC/MS) is described. Immonium ions of constituent amino acids, which were obtained together with molecular ion species by FAB mass spectral analysis of standard microcystins RR, YR, LR, and [D-Asp3] and [Dha7]microcystins LR using flow injection system composed of Frit-FAB probe, showed potential for reliable identification of microcystins by Frit-FAB LC/MS. Frit-FAB LC/MS using a microbore column provided not only the baseline separation of standard microcystins RR, YR, and LR but 200-fold higher sensitivity than that using conventional column. Furthermore, when a selected ion monitoring (SIM) technique was used, the detection limits of microcystins RR, YR, and LR were 300, 350, and 400 pg, respectively, at a signal-to-noise ratio of 5:1, and calibration curves of each microcystin showed a linear relationship from 2 ng to 50 ng. Finally, identification and quantitative analyses of microcystins in water samples were carried out.

Chromatography, Liquid↗
PubMed1995

Menopause-related changes in bone mineral density in Japanese women: a longitudinal study on lumbar spine and proximal femur.

We investigated 2-year longitudinal changes of bone mineral density (BMD) in lumbar spine and proximal femur in 64 Japanese women aged 38-67. Forty subjects were premenopausal (mean age 44.9) and 24 postmenopausal (mean age 54.6) at enrollment of the study. Six subjects experienced menopause during the 2-year study period and were defined as the perimenopausal group. Measurements of BMD were performed using dual-energy X-ray absorptiometry at L2-4, femoral neck, greater trochanter, and Ward's triangle. Paired t test revealed no significant decrease in BMD at any site in the premenopausal group. Significant annual decrease in BMD was observed in the perimenopausal group at L2-4, femoral neck, and greater trochanter. A similar tendency was observed in Ward's triangle, but did not reach statistical significance. In the postmenopausal group, significant decrease in BMD was found at the proximal femur, but not at L2-4. Significant inverse correlation between age and change rate of BMD was found at L2-4, but not at the proximal femur, in premenopausal women. In postmenopausal women, there was a significant association between body weight (BW) change and change rate in BMD at L2-4, femoral neck, or greater trochanter. This association was not found in the premenopausal group. These results suggest that effect of menopause on BMD may be different in individuals and sites of the skeleton. BW change may affect change in BMD in postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1995

Proximal subtotal gastrectomy for the treatment of carcinoma of the upper third of the stomach: its indications based on lymph node metastasis and perigastric lymphatic flow.

To clarify the indications for a proximal subtotal gastrectomy in the treatment of carcinoma in the upper third of the stomach based on lymph node metastases, 1055 patients in whom either a D2 or greater lymph node removal was performed were reviewed. In the patients in which the lesion was confined to the upper stomach and did not invade beyond the muscularis propria of the stomach wall, no metastases to either the lymph nodes above and below the pylorus or the lymph nodes along the greater curvature were observed. A lymphatic flow study revealed a minimal flow to these nodes from the upper stomach in patients without lymph node metastasis, but in cases with lymph node metastases the lymphatic flow changed. The indications for a proximal subtotal gastrectomy for a carcinoma of upper third of the stomach therefore must fulfill the following two conditions: (1) The deepest layer of cancerous invasion does not extend beyond the muscularis propria of the stomach wall, and (2) No macroscopic evidence of lymph node metastasis can be detected during surgery.

Case-Control Studies↗
PubMed1995

Minute malignant islet cell tumor of the pancreas: report of a case.

We present herein the case of a 73-year-old Japanese man in whom a minute malignant islet cell tumor, 7 mm in maximal diameter, was discovered. The patient was admitted to our hospital to undergo a gastrectomy for gastric cancer, at which time preoperative ultrasonography (US) revealed a minute hypoechoic mass located in the head of the pancreas. Endoscopic retrograde pancreatography, angiography, computed tomography, and magnetic resonance imaging failed to reveal the features or location of the tumor; however, these details were obtained by endoscopic and intraoperative US. Although intraoperative fine-needle aspiration cytology of the tumor enabled a diagnosis of islet cell tumor to be made, it failed to provide enough material to evaluate the grade of malignancy, which was confirmed by histologic examination of the enucleated tumor, allowing the appropriate surgical procedure to be decided.

Aged↗
PubMed1995

Involvement of the central nervous system in vibration syndrome.

In order to clarify the involvement of the central nervous system (CNS) in vibration syndrome (VS), patients with VS and age-matched controls were given a questionnaire and neurophysiological tests on auditory brainstem response (ABR), event-related potential (P300), short-latency somatosensory evoked potentials (SLSEP), and blink reflex (BR). Twenty-eight patients with a mean age of 56.3 (SD = 3.01, range 48-65) years from western Japan were examined. They had been on sick leave for an average of 6.13 (SD = 3.2, range 1-13) years at the time of the testing. Almost all were experiencing Raynaud's phenomenon in the winter of 1990-1991. They were not suffering from diseases or injuries which might have affected the CNS function. These patients were divided into two subgroups, one with more symptoms related to the CNS, especially memory and judgment (n = 13, group A), and the other with fewer symptoms (n = 15, group B). Normal controls with an average age of 55.8 (SD = 4.8, 48-65) years were people from the same area who met similar criteria. The ABR parameters of the patients were slightly, but not significantly, delayed compared with those of the controls. The SLSEP and BR parameters of the patients were not delayed. The latencies of P300 in group A were significantly delayed compared with those in the controls. The findings suggest that VS involves the cognitive and attention functions of the cerebral higher function, but not the conduction function in the auditory and somatosensory ascending tract and facial nerve reflex tract in the brainstem.

Central Nervous System↗
PubMed1995

Sulfamethoxazole-trimethoprim double-blind, placebo-controlled, crossover trial in Machado-Joseph disease: sulfamethoxazole-trimethoprim increases cerebrospinal fluid level of biopterin.

We performed a double-blind, placebo-controlled, crossover trial of sulfamethoxazole-trimethoprim (S-T) in 8 patients with Machado-Joseph disease (MJD), and measured the blood and cerebrospinal fluid levels of biopterins, biogenic amines or metabolites, and folate. The clinical results were as follows; mild improvements of hyperreflexia of knee jerks and of rigospasticity of the legs during S-T treatment period. In addition, S-T significantly reduced the times of 8 motor activities on the timed tests. The biochemical results showed that basal levels of all biopterins and homovanillic acid in the cerebrospinal fluid (CSF) were reduced to less than half the levels of those of controls with other neurological diseases. After S-T treatment, total and oxidized form of biopterins in the CSF increased significantly. Therefore, S-T may be effective to neurologic deficits through its mechanism of increasing the level of brain biopterins.

Adult↗
PubMed1995

Mapping of a functional region conferring nuclear localization of pseudorabies virus immediate-early protein.

The immediate-early protein (IE180) of pseudorabies virus (PrV) is localized predominantly in the nuclei of infected cells. To define the nuclear localization signals within IE180, we prepared truncated mutants of IE180 and analyzed their localization in the transfected cells by indirect immunofluorescence. Analysis of mutants truncated from the carboxy-terminal end of the 1460-amino acid polypeptide showed that two regions including a short sequence of basic amino acid residues were associated with the nuclear localization of IE180. To assess whether these regions substantially function as signals for nuclear localization of the IE180 molecule, we then constructed two deletion mutants lacking each region. A mutant lacking amino acids 333 to 575 was detected in the nuclei of the transfected cells, whereas the other mutant lacking amino acids 900 to 950 was detected mainly in the cytoplasm. These results suggest that the region of amino acids 900 to 950 is responsible for nuclear localization of IE180.

Amino Acid Sequence↗
PubMed1995

Cerebrospinal fluid biopterin and biogenic amine metabolites during oral R-THBP therapy for infantile autism.

Treatment with 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (R-THBP) has been suggested to improve autistic behavior. Cerebrospinal fluid (CSF) levels of total biopterin, oxidized and reduced forms of biopterin, homovanillic acid, and 5-hydroxyindoleacetic acid were measured in 14 autistic children and 18 controls to clarify the mechanism of action of R-THBP. The 14 autistic children received R-THBP orally at 1 mg/kg per day; 7 children showed clinical improvement (responders) and the other 7 patients did not (nonresponders). There were no significant differences between responders, nonresponders, and controls in the CSF levels of the metabolites before R-THBP administration. When lumbar puncture was repeated in 6 autistic children in the 24th week of R-THBP therapy, there was no significant change in the CSF levels of any metabolites.

Autistic Disorder↗
PubMed1995

Chronic anterior pallidal stimulation for Parkinson's disease.

We present the case of a 51-year-old female who had a four-year history of Parkinson's disease with severe "on-off' and disabling progression of symptoms on chronic levodopa therapy. After obtaining FDA approval, we implanted a Medtronic deep brain stimulation lead stereotactically into the right anterior pallidum contralateral to her most symptomatologic side. Intra-operative stimulation trials at 100 Hz caused reproducible reversal of akinetic symptoms and simultaneous microelectrode recording of the posteroventral pallidum revealed decreased neural activity during anterior pallidal stimulation. The patient was evaluated pre-operatively and postoperatively using the Hoehn and Yahr Staging Scale, the Unified Parkinson's Disease Rating Scale (UPDRS), videotape, and a computerized data glove. Six months after implantation, the total UPDRS score was decreased from 68 to 8 and Hoehn and Yahr Staging improved from 3.0 to 1.5 during periods of chronic high frequency stimulation. Dramatic improvements in tremor, dystonia, bradykinesia, and akinesia were noted within seconds of stimulator activation and were also objectively measured using a computerized data glove. This case reveals the potential for therapeutic pallidal stimulation for Parkinson's akinetic symptomatology.

Antiparkinson Agents↗