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Biomedical subjects

T Katayama

Publications and source records attributed to T Katayama.

At least 217 records · Page 12Linked to original sources
PubMed1994

Histological findings of capsular delamination of the lens.

Histological findings in a 75-year-old man with idiopathic capsular delamination were reported. The anterior capsules were obtained during extracapsular cataract extraction, and examined by light and electron microscope. The epithelial side of the anterior capsules protruded towards the anterior chamber at the edge of the delaminated areas. This finding has not been described previously, and the defect in this fragile region was thought to be the cause of capsular delamination.

Aged↗
PubMed1994

[Chagas' disease among blood donors in Bolivia].

A questionnaire survey of blood donors at Santa Cruz General Hospital, Bolivia, showed that while there were no seropositive cases of syphilis, HBsAg, and HIV, the prevalence of Chagas' disease was very high (23%) among the 225 blood donors who responded to this questionnaire. Actual cases of Chagasic seropositive blood being used for blood transfusion were seen, including the urgent need for a program for Chagas' disease in Bolivia. From the results of this study, it is recommended that for blood donors from South American countries, the presence/absence of Chagas' disease should be confirmed.

Adolescent↗
PubMed1994

[Identification of the most appropriate time for lung transplantation in the patients with idiopathic interstitial pneumonitis].

In order to identify the most appropriate time for lung transplantation, we examined the natural courses of eight patients who died of idiopathic interstitial pneumonitis (IIP). Five of eight patients died within two years after they were diagnosed as IIP and six died within one year after the last admission. As the disease progressed, arterial oxygen pressure tended to decrease and serum LDH level to increase. But no parameter was able to predict the natural courses of patients. We conclude that it is very difficult to identify the most appropriate time for lung transplantation and the prognosis of IIP patient is very poor. Therefore as soon as patients are diagnosed as IIP, it is mandatory to assess their eligibility for lung transplantation.

Adult↗
PubMed1994

[The effects of various doses of lipopolysaccharide on endotoxin-induced uveitis in rats].

We induced intraocular inflammation by foot pad injection of lipopolysaccharide (LPS) in rats to investigate the inflammatory effects of the various doses of the LPS and the anti-inflammatory effects of prostaglandin (PG) synthetase inhibitor. The aqueous protein concentration curve showed two peaks, an early one at 3 hours and another at 24 hours after the injection, at doses higher than 12.5 micrograms per rat. The PG synthetase inhibitor reduced the aqueous protein concentration by 30 to 60% at both of the two peaks. These results suggest the involvement of PG in the mechanism of the endotoxin-induced uveitis.

Animals↗
PubMed1994

[The relation between Behçet's disease and interleukin-1 beta production].

Interleukin-1 beta (IL-1 beta) is an inflammatory cytokine. We measured its production in 21 Behçet's disease patients, 4 healthy controls, and 4 sarcoidosis patients, by enzyme-linked immunosorbent assay (ELISA) after stimulation with lipopolysaccharide from peripheral blood monocytes. IL-1 beta production of the posterior segment type was significantly greater (p < 0.001) than in healthy controls, sarcoidosis patients, and anterior segment type. In all posterior segment type cases, IL-1 beta production in the active period was greater than in the remission period. IL-1 beta production is considered to be related to posterior segment type attacks of Behçet's disease.

Adolescent↗
PubMed1993

Resetting of cortically induced rhythmical jaw movements by stimulation of the cerebellar interpositus nucleus in the guinea pig.

Effects of stimulation of the cerebellar interpositus nucleus on fictive rhythmical jaw movements induced by stimulation of the cortical masticatory area were studied in ketamine-anesthetized, paralyzed guinea pigs. A short pulse-train applied to the interpositus nucleus caused a phase shift in cortically induced rhythmical jaw movements. A phase transition curve indicated that interpositus stimulation can reset the cortically induced rhythmical jaw movements.

Animals↗
PubMed1993

An amino-terminal fibronectin fragment stimulates the differentiation of ST-13 preadipocytes.

Differentiation of ST-13 preadipocytes into adipocytes was inhibited almost completely by addition of rat plasma fibronectin (FN) (approximately 100 micrograms/mL), but was reversed by GRGDSP cell recognition peptide (1.5 mM) and anti-alpha 5 beta 1. On the contrary, the thermolysin digest of FN stimulated adipocyte differentiation in a dose-dependent manner, in which remarkable increases in the values of the differentiation indexes, the number of adipocytes (8-fold above the control), glycerophosphate dehydrogenase (GPD) activity (12-fold), and triacylglycerol content (5-fold), were observed by inclusion of the thermolysin digest (100 micrograms/mL). The increase in GPD activity by the thermolysin digest was inhibited remarkably (about 70% inhibition) by an antibody directed to the amino-terminal fibrin-binding (Fib 1) domain of FN and slightly (about 15%) by an antibody directed to the central cell-binding (Cell) domain, but not by anti-gelatin-binding domain and anti-carboxy-terminal fibrin-binding domain. Treatment of ST-13 cells by a purified 24K fragment (100 micrograms/mL) derived from the Fib 1 domain caused an over 20-fold augmentation of the GPD activity, accounting for a major part of the differentiation stimulatory activity of the thermolysin digest. The differentiation stimulatory effect of the 24K Fib 1 fragment was not affected by either GRGDSP peptide or anti-alpha 5 beta 1. Thus, FN can regulate adipose development of ST-13 cells by its two antipodal, inhibitory and stimulatory, activities, the latter of which is expressed only upon fragmentation. Proteolytic cleavage of FN may play an important role in controlling the action of FN on adipocyte differentiation.

Adipose Tissue↗
PubMed1993

Importance of Glu-125 in the catalytic activity of human renal dipeptidase.

The carboxyl reagent N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) and dansyl-ethylenediamine have shown to inhibit human renal dipeptidase (hrDP) irreversibly in a time-dependent manner. Cilastatin, a competitive inhibitor of the enzyme, partially protected the enzyme from inactivation. To identify the site(s) modified by EEDQ and dansylethylenediamine, the amino-acid sequence of tryptic fragments of modified enzyme were analyzed extensively. A comparison of the determined amino-acid sequences with the predicted primary structure of hrDP revealed that Glu-125 within the Glu115-Arg138 fragment was modified. In consequence, the role of Glu-125 in catalytic activity was investigated by site-directed mutagenesis. Glu-125 was replaced by a glutamine, aspartic acid or cysteine residue. cDNAs for wild-type or mutated enzymes were expressed in CHO cells, and the resulting proteins were purified to apparent homogeneity. The mutated enzyme, Gln-125-hrDP exhibited specific activity of 28.5 U/mg, corresponding to 11.4% of the wild-type. In contrast, Asp-125-hrDP and Cys-125hrDP were found to be inactive (< or = 0.1% of wild-type enzyme). These results suggest that the polarity and/or length of the side chain of Glu-125 residue are important for the enzyme activity.

Amino Acid Sequence↗
PubMed1993

Effect of total parenteral nutrition on liver mitochondrial function in mature rats.

To evaluate the effects of TPN on the hepatic function, the changes in hepatic energy charge levels, oxidative and phosphorylative activities of mitochondria and serum transaminase were studied, using male Sprague-Dawley rats 240 to 250 g in weight. The rats were randomized into three groups. The first group (TPN-V group, n = 6) was infused with TPN solution via the right jugular vein. The number of calories of TPN solution infused daily was adjusted to provide each rat with 80 kcal/kg/day on the 1st day, 160 kcal/kg/day on the 2nd day and 240 kcal/kg/day on the 3rd day. After the 4th day, 240 kcal/kg/day was given to both groups. The second group (TPN-G group, n = 5) was infused with the same solution via an intragastric route and was given the same calories as the TPN-V group. The third group (control group, n = 6) was given a chow diet with the same calories as the TPN group. At the 13th day, all groups were sacrificed, and the hepatic energy charge (EC) and phosphorylation rate (PR) of hepatic mitochondria were measured, and liver function tests were done. PR was 101.2 +/- 5.0 nmol/mg protein/min in control group, 120.8 +/- 2.7 in TNP-G group and 136.5 +/- 6.2 in TPN-V group. EC was 0.906 +/- 0.006, 0.889 +/- 0.008, 0.831 +/- 0.010, respectively. The liver function tests of all group were normal. In both TPN groups, despite evidence that liver function tests were normal, enhanced mitochondrial phosphorylative activity was observed during the early stage of TPN.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Rat hepatocytes generate peptide leukotrienes from leukotriene A4.

The biosynthetic mechanism of peptide leukotrienes was studied in rat liver. A catalytic activity to synthesize leukotriene (LT) C4 from LTA4 (LTC4 synthesis activity) was shown to be associated mainly with the microsomal fraction of hepatocytes, but also to a small extent with nonparenchymal cells including Kupffer cells, suggesting that the hepatocytes have an ability to generate peptide LTs. Stimulation of the isolated hepatocytes with calcium ionophore (A23187) did not cause any significant production of peptide LTs, whereas addition of LTA4 induced a remarkable generation of peptide LTs in a dose-dependent manner. Addition of LTA4 also augmented the peptide LT production by Kupffer cells, but its amount was much smaller than that by the hepatocytes under the same culture conditions. Coincubation of the hepatocytes and Kupffer cells, following A23187 stimulation, elicited a markedly enhanced production of peptide LTs even without any addition of LTA4, whereas the LT production in the coincubation system was suppressed almost completely by treating the Kupffer cells with a specific inhibitor of 5-lipoxygenase, AA861 (10 microM). An enzymatic cooperation between the hepatocytes and Kupffer cells may play an important role in generating peptide LTs in the liver.

Animals↗
PubMed1993

Follow-up study of anti-hepatitis C virus antibodies in blood donors implicated in post-transfusion non-A, non-B hepatitis.

We retrospectively examined the antibodies to p22, a hepatitis C virus (HCV) nucleocapsid protein, and to c100-3, a HCV nonstructural protein, in donors whose blood was transfused to patients who later developed post-transfusion non-A, non-B hepatitis. Of 13 such blood donors, three seroconverted and three seroreverted with the anti-c100-3 test. In contrast, 12 of the 13 blood donors showed the same results at transfusion and follow-up, and one donor showed seroconversion with the anti-p22 assay. The follow-up study shows that the anti-p22 antibody test provides consistent results and is far more suitable for screening blood than the anti-c100-3 test.

Antigens, Viral↗
PubMed1993

Nucleotide sequence analysis of the gtfT gene from Streptococcus sobrinus OMZ176.

The gtfT gene and its upstream region isolated from the Streptococcus sobrinus OMZ176 chromosomal DNA were sequenced. The gtfT gene was preceded by a potential Shine-Dalgarno sequence. The gtfT gene product, glucosyltransferase (GTF), displays a typical gram-positive bacterial signal peptide sequence and both an active site peptide sequence and carboxy-terminal repeats typical of GTFs. The signal sequence is similar to those of other known GTF proteins. The putative active-site peptide sequence of this enzyme was DGIRVDAVD, which was different by one amino acid from the active-site peptide sequence derived from two different types of the S. sobrinus GTFs reported previously (G. Mooser, S. A. Hefta, R. J. Paxton, J. E. Shively, and T. D. Lee, J. Biol. Chem. 266:8916-8922, 1991). The gtfT gene product has three repeated sequences of 51 to 52 amino acids and a partial repeat of 18 amino acids. Another open reading frame (ORF) was detected in the region immediately upstream of the gtfT gene. The upstream ORF showed substantial DNA homology with the gtfS gene isolated from Streptococcus downei MFe28. The inferred amino acid sequence of the upstream ORF has four repeating units and has extensive homology with the repeated peptides coded by the S. downei gtfS gene. These results suggested that the gtfT gene was a typical gtf gene isolated from the mutans streptococci and that the two gtf genes were located in tandem on the chromosomal DNA of S. sobrinus OMZ176.

Amino Acid Sequence↗
PubMed1993

Serotype-specific amplification of Rickettsia tsutsugamushi DNA by nested polymerase chain reaction.

Polymerase chain reaction (PCR) with nested primer pairs was used to diagnose scrub typhus and identify the Rickettsia tsutsugamushi serotype. The primer pairs used for PCR were designed on the basis of the nucleotide sequence of the gene that encodes the 56-kDa antigen. Serotype-specific primers were used in the second PCR amplification. Five serovariants, the Gilliam, Karp, Kato, Kawasaki, and Kuroki strains of R. tsutsugamushi, were identified by nested PCR. In addition, the serotype identified by PCR with DNA from blood clots was the same as that of the strain isolated from five patients with scrub typhus. These findings indicate that this method is useful for diagnosis and identification of the rickettsial serotype in infected patients.

Base Sequence↗
PubMed1993

Modulation of activin A action and specificity in the rat gonadotrope by protein kinase C.

This study was undertaken to assess the role of protein kinase C (PKC) in activin action in the rat pituitary. Pretreatment with 500 nM phorbol 12-myristate 13-acetate (PMA) for 22-24 h reduced subsequent FSH and LH release (percentage of total cellular FSH and LH released) in response to 100 nM PMA. This action persisted for 2 days after the pretreatment. Pretreatment with 500 nM 4 alpha-phorbol 12,13-didecanoate (4 alpha PDD, a phorbol ester which does not activate PKC) did not affect cell responsiveness to 100 nM PMA. Both PKC-down-regulated cells and cells with a full complement of PKC responded similarly to 100 nM GnRH and 100 microM A23187 during this period. Incubation with 50 ng/ml activin A for 48 h significantly increased both FSH release and total FSH (extracellular plus intracellular) compared to corresponding basal values in PMA-pretreated cells, as well as in vehicle-or 4 alpha PDD-pretreated cells. Activin stimulation of basal FSH release and total FSH was significantly more potent in PMA-pretreated cells than in cells not pretreated with PMA. Activin did not alter basal LH release or total LH in vehicle- or 4 alpha PDD-pretreated cells but significantly increased both in PMA-pretreated cells. When PMA was present only during the initial 2 h of the 22- to 24-h pretreatment period at 50 nM, PKC was not down-regulated. In these cells, the potency of activin stimulation of basal FSH release was not affected, but stimulation of basal LH release by activin was still observed. These results suggest that PKC is not required for activin to stimulate FSH release but is involved as a modulator of potency and specificity of the activin action.

Activins↗
PubMed1993

DNA sequence of the glucosyltransferase gene of serotype d Streptococcus sobrinus.

A glucosyltransferase (GTF) gene was cloned into Escherichia coli from serotype d Streptococcus sobrinus OMZ176. Transformed E. coli strain MI expressed water-insoluble glucan synthesizing activity. Restriction enzyme map of pGT31 extracted from MI shows that the enzyme gene exists in the 6.4-KB PstI-fragment inserted into pBR322 vector. DNA sequence analysis indicates that a single ORF (530-5,300) is located in the PstI-fragment. The putative amino-acid composition (1,590 residues) resembles those of other GTF-I enzymes obtained from serotype g S. sobrinus and serotype h Streptococcus downei. However, at the same positions of the sequence, 18 and 142 amino-acid residues are different between serotype d and g, and serotype d and h GTF-I enzymes, respectively. The differences between serotype d and h GTF-Is are distributed in N and C-terminal regions.

Amino Acid Sequence↗
PubMed1993

Responses of tissue ascorbic acid and of serum cholesterol, alpha-tocopherol, and ceruloplasmin in rats to dietary level of cystine.

The present study was conducted with growing rats to examine effects of addition of 0.3, 1.0, 2.5, and 5% L-cystine to 10 or 25% casein diet on tissue ascorbic acid and on serum cholesterol, alpha-tocopherol, and ceruloplasmin activity. Addition of 0.3-1% cystine to 10% casein diet caused the maximum growth and addition of 5% cystine to 25% casein diet depressed the growth. Increases in liver levels of ascorbic acid and in serum levels of cholesterol and alpha-tocopherol were observed with addition of 5% cystine to 10 and 25% casein diets as compared to the diets without addition of cystine. Addition of 0.3-5% cystine to 10% casein diet and addition of 5% cystine to 25% casein diet caused a decreased activity of serum ceruloplasmin. The changes in liver ascorbic acid, serum cholesterol, and serum alpha-tocopherol and in ceruloplasmin activity by dietary cystine correlated with the changes in liver levels of non-protein sulfhydryl.

Animals↗
PubMed1993

Experience with a new intraurethral stent for high-risk patients with benign prostatic hypertrophy.

Eight patients with benign prostatic hypertrophy (BPH), considered as a high risk for an operation because of severe accompanying disease, were treated with a self-retaining intraurethral catheter set. Two patients were judged unfit for operation (one because of severe cardiac failure, the other because of severe respiratory failure) and 1 patient rejected an operation. The BPH surgery was postponed in the others because of recent operations for such diseases as gastric cancer or because of severe gastric ulcer. All patients voided freely after stent placement and were continent. The device was left in place for 1 to 16 weeks. The chief complaint was frequency of voiding, with intervals of 1 to 2 hours. Some micturition discomforts such as urgency were recognized in 2 patients, but disappeared within 1 to 2 days. Pyuria observed before treatment disappeared in all but 1 patient. Average residual urine volume calculated on ultrasonograms was 54 ml. Stone formation was demonstrated in 1 patient 9 weeks after placement. We concluded that the intraurethral stent is an effective device for high-risk patients with BPH. However, a longer follow-up study will be needed to exclude late side effects.

Aged↗