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Biomedical subjects

S Kato

Publications and source records attributed to S Kato.

At least 955 records · Page 53Linked to original sources
PubMed1994

The novel effects of 3,5,3'-triiodo-L-thyronine on myocyte contractile function and beta-adrenergic responsiveness in dilated cardiomyopathy.

Medical management of patients with chronic left ventricular dysfunction continues to be a difficult problem. Recent clinical and experimental studies have suggested that 3,5,3'-triiodo-L-thyronine improves left ventricular pump function. However, whether 3,5,3'-triiodo-L-thyronine directly improves myocyte contractile function in cardiomyopathic states is unknown. Accordingly, this study examined the direct effects of 3,5,3'-triiodo-L-thyronine on isolated myocyte contractile function in cardiocytes obtained from control (n = 6) pigs and pigs with tachycardia-induced dilated cardiomyopathy (atrial pacing at 240 beats/min for 3 weeks; n = 6). Myocyte percent shortening and velocity of shortening were obtained at baseline and in the presence of 3,5,3'-triiodo-L-thyronine doses of 80 and 100 pmol/L. For both control and dilated cardiomyopathy groups, 3,5,3'-triiodo-L-thyronine caused a significant increase in myocyte contractile function. For example, a 100 pmol/L dose of 3,5,3'-triiodo-L-thyronine increased myocyte velocity of shortening by 51% in control myocytes and by 54% in dilated cardiomyopathy myocytes compared with baseline. A second series of experiments was performed to determine whether 3,5,3'-triiodo-L-thyronine altered the responsiveness of the beta-adrenergic receptor system in control and dilated cardiomyopathy myocytes. Myocyte contractile function was examined during beta-adrenergic stimulation with isoproterenol alone and in myocytes preincubated with 3,5,3'-triiodo-L-thyronine doses of 80 and 100 pmol/L to which isoproterenol was added. Isoproterenol alone increased velocity of shortening by 139% in control and by 233% in dilated cardiomyopathy myocytes compared with baseline. This was significantly greater than the increase with 3,5,3'-triiodo-L-thyronine alone. 3,5,3'-triiodo-L-thyronine followed by isoproterenol increased velocity of shortening by 245% in control and 313% in dilated cardiomyopathy myocytes compared with baseline. This was significantly greater than the response with 3,5,3'-triiodo-L-thyronine or isoproterenol alone and appeared to be greater than an additive response. The results from this study clearly demonstrated that 3,5,3'-triiodo-L-thyronine directly augmented myocyte contractile function in both control and dilated cardiomyopathy myocytes. In addition, 3,5,3'-triiodo-L-thyronine enhanced the contractile response to beta-adrenergic stimulation in dilated cardiomyopathy. This study provides unique evidence to suggest that 3,5,3'-triiodo-L-thyronine may be a useful adjunct to conventional inotropic support in the setting of advanced left ventricular dysfunction.

Animals↗
PubMed1994

Hepatic resection under the intermittent selective portal branch occlusion by balloon catheter.

BACKGROUND: In hepatic resection, it is important to control intrahepatic blood flow to minimize blood loss. Intermittent and selective vascular occlusion, if possible, are advisable. STUDY DESIGN: For this purpose, we created the double balloon catheter, which when introduced into a lobar or a smaller branch of the intrahepatic portal vein through a branch of the ileocolic vein, made it possible to occlude these branches temporarily during hepatic resection. The small balloon located at the tip of the catheter made it easy to introduce the catheter to the portal branch selectively, under the guidance of ultrasonography. Another balloon was inflated intermittently to occlude selective portal blood flow. Using this technique, hepatic resection was achieved in 18 consecutive patients: 13 with hepatocellular carcinomas (11 with cirrhosis, two with chronic hepatitis), one with cholangiocellular carcinoma, three with metastatic carcinomas, and one with intrahepatic calculi. RESULTS: In these cases, 19 hepatic resections were performed; two left hepatectomies, one extended right hepatectomy, one right hepatectomy, six segmentectomies, eight subsegmentectomies, and one partial hepatectomy. In each case, well demarcated hepatic tissue delineated by ischemic change was removed with minimal bleeding and little impairment to the residual hepatic tissue, resulting in a good postoperative course. CONCLUSIONS: This double balloon catheter can replace the dissection of the hepatoduodenal ligament for hepatic resection, which causes bleeding, especially in patients with cirrhosis, and results in less cell injury of the residual hepatic parenchyma.

Aged↗
PubMed1994

Hepatic recovery after biliary drainage in experimental obstructive jaundice complicated by biliary infection.

The effects of an association of biliary infection and bile stasis on the recovery process of the impaired structure and function of the cholestatic liver after biliary drainage were studied in experimental animals. Obstructive jaundice was induced by clamping a tube inserted into the common bile duct of rats, while at the same time Escherichia coli bacteria were introduced into the tube to induce biliary infection. After one week, the biliary obstruction was removed. After 14 days of biliary drainage, the impaired structure and function of the cholestatic liver without biliary infection were remarkably improved, having returned almost to normal, while in the cases with biliary infection, the impairments were far less improved, especially with respect to mitochondrial function. These results suggest that major hepatic surgery should not be employed in patients with obstructive jaundice in the presence of biliary infection and should be delayed until hepatic function has recovered sufficiently after biliary drainage.

Animals↗
PubMed1994

Analysis of cytochrome P450 2E1 genetic polymorphisms in relation to human lung cancer.

Human cancer risk assessment using molecular genetic techniques is a rapidly emerging field. Many studies suggest that both inherited and acquired genetic predispositions play an important role in carcinogenesis. Cytochrome P450 (CYP) 2E1 is involved in the metabolic activation of N-nitrosamines and other low molecular weight compounds. A recently described genetic polymorphism of CYP2E1 [DraI restriction fragment length polymorphism (RFLP)] has been associated with an increased risk of lung cancer in Japanese. We have assessed the allelic frequency of three RFLPs (PstI, RsaI, and DraI) in African-Americans (n = 109), Caucasian Americans (n = 153), and octogenarian Japanese (n = 42), and also in a United States case-control study of lung cancer (histologically confirmed lung cancer, n = 58; controls, n = 56; total, n = 114). The relationship of the CYP2E1 DraI polymorphism to other CYP2E1 polymorphisms (PstI and RsaI RFLP) was examined. The allelic frequency of the DraI C minor allele for all subjects was 0.09 in Caucasians, 0.09 in African-Americans, and 0.31 in Japanese. In the case-control study of lung cancer, no association of the CYP2E1 DraI genotype with lung cancer was found (odds ratio, 1.57; 95% confidence interval, 0.59-4.18). Comparison after discordant CYP2E1 genotypes suggests the presence of different haplotypes in Americans and Japanese. These results indicate that the CYP2E1 DraI RFLP is probably not a cancer risk factor in United States Caucasian or African-Americans, although statistical power is limited given the low frequency of the CYP2E1 DraI C minor alleles.

Aged↗
PubMed1994

Sex determination from the tibia: standards for contemporary Japan.

It is vital that skeletal biologists and forensic anthropologists observe populations over time so that changes can be detected and monitored. The purpose of this study is to determine if temporal changes are manifest in the skeleton and, if so, develop appropriate standards to determine sex from the tibia in the contemporary inhabitants of Japan. Osteometric data were obtained from 84 recent Japanese skeletons located at Jikei Medical University, Tokyo. The collection was assembled from the anatomy dissecting room between 1960-1970. With a mean age of about 56 years for males and 51 for females, this sample represents individuals who lived through WWII. Seven tibial measurements were taken and subjected to SPSS-X discriminant function analysis. Results indicated that proximal and distal breadth measurements were selected by the stepwise procedure as the most discriminating. In addition, a number of combinations of measurements were used to develop formulae that would be suitable for fragmentary bones. Average prediction accuracy ranged from 80% from minimum shaft circumference to 89% with proximal epiphyseal breadth. Classification accuracy was higher in males (96%) than in females (79%). Compared with earlier studies of the Japanese, Jikei tibiae are longer, especially in females and thus exhibit less sexual dimorphism. The present research provides new standards that better reflect the Japanese people of today. Furthermore, unlike earlier length based formulae, these results allow sexing from fragmentary bones.

Female↗
PubMed1994

Development-related changes in matrix metalloproteinase expression in human aortic smooth muscle cells.

BACKGROUND: It is known that extracellular matrix-degrading enzymes play an important role in tissue remodeling and that large amounts of structural proteins including types I, III, IV, and V collagens and elastin are produced by smooth muscle cells (SMC) in the arterial wall. We have recently shown that matrix metalloproteinases (MMPs) produced by human aortic medial smooth muscle cells are closely related to the proliferation of the cells, leading to the formation of atherosclerotic plaques, characteristic of intimal remodeling. For a better understanding of the mechanism of atherogenesis, therefore, it is important to clarify the relationship between the production of matrix-degrading enzymes and artery development. EXPERIMENTAL DESIGN: In vivo or in vitro synthesis of MMPs by SMC was analyzed by immunohistochemistry and immunoblotting. Elastase activity in the culture medium was also estimated. RESULTS: Production of proMMP 1, 2, and 3 was detected in cultured SMC isolated from the aortas of both neonates and fetuses; in medial SMC cultured from young individuals, production of proMMP-1 and -3 was extremely decreased, but was apparent in intimal SMC. Immunohistochemical observation indicated that in the media of fetal or neonatal aorta, SMC synthesized large amounts of the three proMMPs; in aortas from older individuals, proMMP-2, but not proMMP-1 and -3, was detected in the media, and relatively large amounts of proMMP-1, -2, and -3 were produced by SMC in the slightly thickened intima. Assay of elastase activity in the culture medium gave results similar to those for MMPs. CONCLUSIONS: We conclude that the production of proMMP-1 and -3 is associated with phenotypic modulation of SMC to a "synthetic" state, and that the ability of SMC to produce MMPs plays an important role in the development and/or aging of the human aorta through remodeling of the extracellular matrix; furthermore elastase is also involved in these processes in the arterial wall.

Adolescent↗
PubMed1994

[Expression of rat type 2C alpha protein phosphatase in Saccharomyces cerevisiae cells].

In the course of a study to elucidate the physiological functions of type 2C protein phosphatase(PP2C), we investigated the effects of overexpression of the enzyme protein on the physiology of eukaryotes. In this study, we demonstrated that the overexpression of PP2C alpha caused a decreased growth rate and an increased UV-sensitivity of the yeast cells. We also showed that the expressed PP2C was phosphorylated by casein kinase II in the cells.

Animals↗
PubMed1994

[Current topics in nuclear receptor study].

Nuclear receptors for steroid/thyroid hormones and fat-soluble vitamins A and D act as ligand-inducible transcriptional factors. Recent progress in nuclear receptor study showed that nuclear receptors transmit the signals of those ligand into gene expression. In this article, some topics in this field were illustrated with special attention to cancer and retinoid actions. Functional analysis of target enhancer elements of distinct classes of nuclear receptors revealed the target specificity and unselectivity. Some of molecular mechanism for oncogenesis and retinoid actions have been clarified at nuclear receptor levels.

Animals↗
PubMed1994

Combination therapy with transcatheter arterial embolization and percutaneous ethanol injection for advanced hepatocellular carcinoma.

The effectiveness of transcatheter arterial embolization (TAE) combined with percutaneous ethanol injection (PEI) was investigated in 18 patients with advanced hepatocellular carcinoma (HCC), and compared with 18 patients with HCC treated by TAE therapy alone. In both groups, patients had multiple lesions or a single lesion larger than 3 cm. The pretreatment characteristics of the patients in the two groups showed that serum bilirubin in the TAE-PEI group was significantly higher than that in the TAE-only group, but that the patients in the two groups were comparable in all other respects. The cumulative survival rate of the TAE-PEI group estimated by the Kaplan-Meier method was 100% for 10 months, 82% for 20 months, 53% for 30 months and 18% for 40 months, whereas that of the TAE-only group was 75% for 10 months, 50% for 20 months, 30% for 30 months and 30% for 40 months. The survival rate in the TAE-PEI group was significantly higher than that in the TAE group. Moreover, the survival rate of patients whose main tumor was 4 cm or larger, was significantly higher in the TAE-PEI group than that in the TAE-only group. The average survival period of these patients in the TAE-PEI group was five times as long as that in the TAE-only group. The survival rate of Child's B and C patients in the TAE-PEI group was significantly higher than that in the TAE-only group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

[Psychopathological study of hypochondriaco-cenestopathic symptoms in schizophrenia].

There is evidence that the psychiatric importance of hypochondriacal or cenestopathic symptoms in schizophrenia is prone to be neglected, in so far as these symptoms are expressed through the discourse of somatic medicine. Psychopathological studies of these symptoms are few as compared to studies of other schizophrenic symptoms such as delusion or verbal acoustic hallucination. However, it could be said that such study is indispensable in developing both an understanding of schizophrenics and therapeutic strategies for the treatment of them, in so far as hypochondriaco-cenestopathic symptoms directly indicate a pathology of body-consciousness in schizophrenia. Motivated by these practical as well as theoretical demands, the author presents first of all statistical characteristics of hypochondriaco-cenestopathic symptoms based on a longitudinal study of 183 schizophrenic patients, who were observed for at least 5 years. All the patients satisfied the DSM-III-R criteria for schizophrenia. Taking into consideration these statistical characteristics, as well as certain detailed representative cases, the author proposes a new psychopathological perspective of the hypochondriaco-cenestopathic symptoms in schizophrenia. The essential result of this statistical investigation is summarized as follows. 81 schizophrenic patients exhibited the hypochondriaco-cenestopathic symptoms, accounting for 44.3% of the sample. If we exclude the cases which presented physical experience of being influenced (physikalische Beeinflussungserlebnis), appearance frequency of hypochondriaco-cenestopathic symptoms accounted for 27.9% of the sample. Among the manifestations of these symptoms, uncharacteristic somatic complaint was the most frequent. Here, the most common was pain of body (especially headaches). The second most common was complaint of easy fatigability. Concerning the appearance pattern of the symptom, we found no significant difference between the acute and chronic types, nor between the early and tardive types, while the complex type was significantly more frequent in comparison with the simple type. Among the other symptoms that co-occurred with the hypochondriaco-cenestopathic symptom, the most common was acoustic hallucination, whose frequency was highly statistically significant when compared to the non hypochondriaco-cenestopathic group. Regarding the relationship of the hypochondriaco-cenestopathic symptom with the subtypes of schizophrenia, the proportion of the paranoid type was significantly high in the non hypochondriaco-cenestopathic group.

Adolescent↗
PubMed1994

Expression of gamma-glutamyl transpeptidase mRNA after depletion of glutathione in rat liver.

Gamma-glutamyl transpeptidase (gamma-GT) is the enzyme in the gamma-glutamyl cycle which mediates the first step of glutathione degradation. Recently, it has been reported that diethyl maleate, a glutathione-depleting agent, enhanced hepatic gamma-GT activity. In this study, we examined how gamma-GT mRNA was expressed after the depletion of glutathione by using the RT-PCR method and in situ hybridization technique with digoxigenin-labeled oligonucleotide probe. We could detect hepatic gamma-GT mRNA in the epithelial cell of bile duct and the cytoplasm of hepatocytes in the periportal area, even in control rats. Furthermore, we found that the expression of gamma-GT mRNA was expanded to hepatocytes of a whole lobule 12 hr after depletion of glutathione by diethyl maleate, followed by the return to the pretreatment condition under which gamma-GT mRNA appears to be controlled in correlation with hepatic glutathione levels. These results suggest that the depletion of glutathione may induce hepatic gamma-GT activity through an increased synthesis of its mRNA.

Animals↗
PubMed1993

Acquisition of maturational competence in in vitro grown mouse oocytes.

The maturational competence of the in vitro grown mouse oocytes of various sizes was examined, and was compared to that of oocytes of equivalent chronological age which grew in vivo. Oocyte-granulosa cell complexes isolated from 10-day-old female mice were cultured for 10 days in vitro in the presence of 2 mM hypoxanthine to maintain the meiotic arrest. When the in vitro grown oocytes were denuded and cultured for further 24 h in the hypoxanthine-free medium, 9, 37, and 100% of oocytes of 60-64.5, 65-69.5, and over 70 microns in diameter underwent germinal vesicle breakdown (GVBD), respectively. Of those oocytes which underwent GVBD, 19, 37 and 68% of oocytes larger than 60, 65, and 70 microns progressed to metaphase II, respectively. No oocyte less than 60 microns resumed meiosis. The parallelism found in the oocyte size and maturational competence was similar to that of their in vivo counterparts collected from 20-day-old mice. A significant proportion of the in vitro grown oocytes, however, formed a pronucleus-like structure(s) after maturation culture, indicating that they could not maintain a normal arrest at metaphase II.

Animals↗
PubMed1993

cDNA cloning and pharmacological characterization of an opioid receptor with high affinities for kappa-subtype-selective ligands.

The amino acid sequence of a rat opioid receptor, designated as ROR-D, has been deduced by cloning and sequencing the cDNA. The ROR-D expressed from the cDNA exhibits high affinities for ligands selective for the opioid receptor kappa-subtype and low affinities for ligands selective for the delta- and mu-subtypes. RNA blot hybridization analysis indicated that ROR-D mRNA is distributed in cerebrum and brainstem but not in cerebellum.

Amino Acid Sequence↗
PubMed1993

Primary structures and expression from cDNAs of rat opioid receptor delta- and mu-subtypes.

The complete amino acid sequences of rat opioid receptors (designated as ROR-A and ROR-B) have been deduced by cloning and sequencing the cDNAs. The ligand-binding properties of ROR-A and ROR-B expressed from the cloned cDNAs in Chinese hamster ovary cells correspond most closely to those of the pharmacologically defined delta- and mu-opioid receptor subtypes, respectively. RNA blot hybridization analysis revealed that cerebrum and brainstem contain both ROR-A and ROR-B mRNAs, whereas neither ROR-A nor ROR-B mRNAs can be detected in cerebellum.

Amino Acid Sequence↗
PubMed1993

Human cDNA encoding DnaJ protein homologue.

We have cloned a cDNA encoding a DnaJ-like protein from the human fibrosarcoma HT-1080 cDNA library. This cDNA encodes a protein of 397 amino acid residues whose sequence shows 38.2% identity with the Escherichia coli DnaJ protein and 47.2% with the yeast DnaJ homologue along the entire length. Since the sequence contains the N-terminal domain region conserved in DnaJ family members and the four repeats of the Cys-X-X-Cys-X-Gly-X-Gly motif which are characteristic of DnaJ proteins, we conclude that this cDNA clone encodes the human homologue of DnaJ.

Amino Acid Sequence↗
PubMed1993

Vitamin D receptor gene expression is up-regulated by 1, 25-dihydroxyvitamin D3 in 3T3-L1 preadipocytes.

Vitamin D3, especially 1, 25-dihydroxyvitamin D3 (1, 25 (OH)2 D3), has been shown to inhibit the differentiation of preadipose cells. In the present study, the expression of vitamin D receptor (VDR) was examined by Northern blot analysis in rat adipose tissue and mouse 3T3-L1 adipose cells. The adipose tissue and 3T3-L1 cells expressed mRNA for VDR. Treatment of 3T3-L1 cells with 1 microM 1, 25 (OH)2 D3 led to a 4-5 fold increase in the VDR mRNA level. VDR mRNA expression was rapidly (within 4 hr) induced by physiological concentrations of 1,25 (OH)2 D3 in a dose-dependent manner. The induction of VDR expression did not require de novo protein synthesis but was completely abolished by an inhibitor of RNA synthesis.

3T3 Cells↗