Biomedical subjects

H Yano

Publications and source records attributed to H Yano.

At least 325 records · Page 18Linked to original sources

PubMed1993

Influence of dietary medium- and long-chain triglycerides on fat deposition and lipogenic enzyme activities in rats.

The present study investigates fat deposition, variances of fatty acid (FA) composition, and lipogenic enzyme activities through dietary medium- and long-chain triglyceride (MCT and LCT) supplementation in growing rats. Eighteen male Wistar rats were divided into three groups and fed isocalorically for 4 weeks with control (based on AIN 76), MCT (C8:0 26%), or LCT (corn oil 25%) diets. Compared to the control group with 0.28 +/- 0.01, feed efficiency was lower in the MCT rats and greater in the LCT rats (0.24 +/- 0.01 and 0.33 +/- 0.01, respectively). Weights of perirenal and epididymal adipose tissue pads of the MCT rats were similar to those of the control group, but were significantly lower than those of the LCT group. Whole-body carcass components data of MCT rats showed the decrease in moisture and protein contents compared to those of control and LCT rats. Fat content of LCT rats was 25-30% higher than those of the MCT and control group. Glucose-6-phosphate dehydrogenase, citrate cleavage enzyme, and malic enzyme activities of liver and epididymal adipose tissue were markedly low in LCT rats. In the MCT group, however, lipogenic enzyme activities were not suppressed, and malic enzyme activity was drastically increased. FA composition of whole-body triglycerides and epididymal adipose tissue in MCT rats showed that C16:0 and C16:1 levels were higher than those of the LCT rats. In contrast, FA composition of the LCT group presented high C18:2 content.(ABSTRACT TRUNCATED AT 250 WORDS)

ATP Citrate (pro-S)-Lyase↗

PubMed1993

A molecular inventory of human pancreatic islets: sequence analysis of 1000 cDNA clones.

The islets of Langerhans play a central role in glucose homeostasis by secreting the polypeptide hormones insulin and glucagon. They are comprised primarily of four endocrine cell types: insulin-secreting beta-cells which represent about 70% of the cells in the islet along with smaller number of cells secreting glucagon, somatostatin and pancreatic polypeptide. Diabetes mellitus results from the specific loss or dysfunction of the beta-cells. Because of the central role of the islets of Langerhans in the regulation of glucose homeostasis, we are preparing a database of genes expressed in this tissue. One thousand cDNA clones randomly isolated from a human pancreatic islet library were partially sequenced yielding 280 kilobases of sequence. Database searches indicated that 397 of the cDNAs represented known human genes or human homologs of genes identified in other species and a further 58 sequences corresponded to expressed sequence tags identified in other tissues or cells (contamination by exocrine pancreatic tissue was estimated to be less than 10%). 545 of the cDNAs were not related to any other sequences in the databases. The islet cDNA collection provides a unique source of genes for genetic studies of diabetes as well as for molecular studies of islet function in normal and diabetic states.

Animals↗

PubMed1993

Pulmonary alveolar proteinosis. Xe-133 scintigraphic findings before and after bronchopulmonary lavage.

A 44-year-old woman with pulmonary alveolar proteinosis was treated by repeated unilateral bronchopulmonary lavages over 6.5 years. The effectiveness of the treatment was assessed by Xe-133 scintigraphy as well as lung function tests and chest roentgenograms. Xe-133 scintigraphy clearly demonstrated improvement of regional ventilation and perfusion, and equalization of the ventilation and perfusion ratio. Therefore, Xe-133 scintigraphy was found to be useful in the analysis of changes in regional aeration, ventilation, and perfusion before and after bronchopulmonary lavage in pulmonary alveolar proteinosis.

Adult↗

PubMed1993

Increased expression of glucose transporter GLUT-4 in brown adipose tissue of fasted rats after cold exposure.

Cold exposure has been shown to increase glucose uptake specifically in brown adipose tissue (BAT), the major site for sympathetically controlled metabolic heat production. In this study, the relationship between glucose uptake and glucose transporters (GLUT) was examined in rats exposed to cold for various periods. To minimize the stimulatory effect of circulating insulin, all animals were starved for 20-24 h before the measurements. Acute (4 h) cold exposure had no effect on protein and mRNA levels of GLUT-4, the predominant isoform of GLUT in BAT, despite a significant increase in cellular glucose uptake. Prolonged (1-10 days) cold exposure produced a parallel increase in GLUT-4 expression and glucose uptake in BAT. In contrast, cold exposure had no noticeable effect on GLUT-1, another isoform of GLUT in BAT, and on GLUT-4 in other insulin-sensitive tissues such as white adipose tissue and muscles. The increased glucose uptake and GLUT-4 expression were completely abolished after surgical sympathetic denervation. These findings suggest that cold exposure increases glucose uptake in BAT by at least two distinct mechanisms, both of which are dependent on sympathetic nerve: 1) an increase in the amount of GLUT-4 due to the stimulation of its de novo synthesis, and 2) an increase without stimulation of GLUT synthesis, probably due to the change in the transport activity of GLUT-4 and/or its translocation from an intracellular pool to the plasma membrane.

Adipose Tissue↗

PubMed1993

The role of complement-derived chemotactic factors in lung injury induced by preformed immune complexes.

Our previous studies have suggested a role for complement fragments presumably activated by immune complexes in patients with hypersensitivity pneumonitis. The present study has shown that circulating complement depletion by cobra venom factor resulted in the reduction in severity of immune-complex-mediated pulmonary inflammation. The activity of chemotactic factors for neutrophils generated in bronchoalveolar lavage fluids in complement-depleted animals was significantly diminished to 61.2% compared to the undepleted animals. In addition, reduced activity of chemotactic factors resulted in a marked reduction of accumulation of neutrophils in bronchoalveolar lavage fluids indicating that chemotactic factors play an important role in the sequestration of neutrophils on the alveolar side of the lung. In conclusion, chemotactic factors in bronchoalveolar lavage fluids which preceded the accumulation of polymorphonuclear cells are partially derived from complement.

Alveolitis, Extrinsic Allergic↗

PubMed1993

Torsion of the gallbladder in a thirteen year old boy--case report.

Torsion of the gallbladder in a child is rare and only 23 cases in children have been reported in Japan. A preoperative diagnosis is very difficult and only four cases have been diagnosed, preoperatively, to date. In the case reported here the suspected preoperative diagnosis was an acute cholecystitis. During the operation, the gallbladder was found to be enlarged to twice the normal size and twisted 540 degrees in a clockwise direction around the cystic duct. A cholecystectomy with abdominal drainage was successfully performed; and the patient was discharged in good condition, 13 days after the operation. It was concluded that one of the most important features for the preoperative diagnosis of torsion of the gallbladder is a dislocation on ultrasonography.

Adolescent↗

PubMed1993

Increased incidence of cholestasis during total parenteral nutrition in children--factors affecting stone formation.

Cholelithiasis is extremely unusual in infants and children. Recently, some cases of cholelithiasis associated with total parenteral nutrition (TPN) have been reported. A group of 400 children receiving TPN were evaluated prospectively for the presence of gallstones and sludge in this report. Eight children (2%) were determined by ultrasonography to have developed cholelithiasis. All of these patients had received large amounts of amino acids (> or = 1.8g/kg/day) and relatively low amounts of fat (< or = 1.7g/kg/day) with a high ratio of non-protein: kcal/ml (> 0.8). It was concluded that the administration of large amounts of amino acids and a high ratio of non-protein: kcal/ml enhanced the risk for formation of gallstones and sludge. Conversely, these are prevented by the administration of appropriate amounts of fat.

Adolescent↗

PubMed1993

Splice variant of the somatostatin receptor 2 subtype, somatostatin receptor 2B, couples to adenylyl cyclase.

The diverse biological actions of somatostatin (SRIF) are mediated by a family of receptors, of which five have been cloned and characterized. One of the SRIF receptor subtypes, SSTR2, has been shown to exist in two forms. SSTR2A and SSTR2B are 369 and 346 amino acids in size, respectively, and differ in length and amino acid sequence in their intracellularly located carboxyl termini. SSTR2A and SSTR2B are generated by alternative splicing of SSTR2 mRNA. We previously characterized mouse SSTR2A and showed that it could be distinguished from other cloned SRIF receptor subtypes by its high affinity for MK-678 and its lack of coupling to adenylyl cyclase. To determine whether the properties of mouse SSTR2A and SSTR2B differ, we have expressed both in COS-7 cells and characterized their ligand-binding properties and ability to couple to adenylyl cyclase. The two receptors exhibited similar affinities for a number of SSTR2-selective agonists such as MK-678. Pretreatment with SRIF of COS-7 cells expressing each receptor reduced high affinity agonist binding to both SSTR2A and SSTR2B, indicating that both receptors can be regulated. Furthermore, agonist binding to both receptors was reduced by GTP analogs and Na+, indicating that they both associate with G proteins. As shown previously, SSTR2A could not mediate SRIF inhibition of forskolin-stimulated cAMP formation. In contrast, SSTR2B was coupled to adenylyl cyclase and was able to mediate SRIF inhibition of forskolin-stimulated cAMP formation. Thus, SSTR2A and SSTR2B differ in their ability to couple to adenylyl cyclase. Because SSTR2A and SSTR2B differ only in the length and amino acid sequence of their carboxyl termini, these findings imply that the carboxyl-terminal 15 residues of SSTR2B may be involved in coupling this receptor to adenylyl cyclase.

Adenylyl Cyclases↗

PubMed1993

[Pathogenesis of development of lung cancer in idiopathic interstitial pneumonia--growth factors in bronchoalveolar lavage fluid].

It has been generally accepted that lung fibrosis as in idiopathic interstitial pneumonia (IIP) is frequently associated with the development of lung cancer. This observation implies that the mechanism involved in carcinogenesis and/or enhanced proliferation of cancer cells is common to the fibrosing process. However, there are few studies reported on the pathogenesis of associated lung cancer except for several studies assessed from the point of view of surgical pathology. This study was undertaken to learn whether BAL fluid, which reflects the local milieu of the fibrosing process, enhances the proliferation of human lung cancer cell line Lu-99, Lu-65 and rat lung fibroblasts as assessed by 3H-thymidine incorporation. BAL fluid was obtained from patients with IIP (n = 8) and normal volunteers (n = 8). BAL fluids from patients with IIP enhanced the mean incorporation of 3H-thymidine of Lu-99 up to 3.6 times (p < 0.01) compared to that of normal volunteers. Furthermore, the mean incorporation of Lu-65 was increased up to 1.8 times (p < 0.05) by BAL fluids from patients with IIP. In contrast, BAL fluids from patients caused no significant increase of the mean incorporation of rat lung fibroblasts as compared to normal BAL fluids. The enhancing activities on the growth of cancer cell line Lu-99, Lu-65 were eluted in several fractions by high performance liquid chromatography using Superose 12. These observations indicate that the BAL fluid of IIP patients contains factors enhancing the growth of cancer cells.

Aged↗

PubMed1993

[Septic shock induced by extracorporeal shock wave lithotripsy treatment with percutaneous nephrostomy in 5 cases with urolithiasis].

We have experienced 5 cases of septic shock induced by extracorporeal shock wave lithotripsy (ESWL) and percutaneous nephrostomy. We suspected 5 causes of septic shock; severe hydronephrosis, nephrostomy tube itself, an increase of intrarenal pressure, bacteria in urinary stone, and hepatic failure. Based on the above suspected causes of septic shock, we suggested 3 prophylactic treatments for septic shock; a preventive administration of antibiotics before ESWL and percutaneous nephrostomy, proper management of nephrostomy tube, and early diagnosis and treatment for septic shock.

Aged↗

PubMed1993

Postoperative motor function and mucosal blood flow of lower esophagus: comparison between terminal esophagoproximal gastrectomy and esophageal transection for esophageal varices.

Reflux esophagitis and anastomotic ulcer are potential complications associated with surgery for esophagogastric lesions. This study compared 10 cases following terminal esophagoproximal gastrectomy (TEPG) for esophageal varices and 20 cases following esophageal transection (ET) for esophageal varices with respect to postoperative motor function and mucosal blood supply, to ascertain the reason for the development of anastomotic ulcer. Endoscopic findings showed that anastomotic ulcers were detected more often after TEPG than after TR. Maximum swallowing pressure, high pressure zone pressure, and length did not differ between the two groups. However, maximum swallowing pressure in the lower esophagus after both procedures was significantly lower than in the control group (20 cases; p < 0.01). The results, measured by reflectance spectrophotometry, showed that the index of esophageal mucosal blood volume following TEPG is significantly lower than that following ET and in non-operated esophageal varices (10 cases; p < 0.01). Yet the index of oxygen saturation of hemoglobin was similar in the three groups. This study has demonstrated that patients undergoing TEPG have mucosal ischemia of the lower esophagus, causing the development of anastomotic ulcers.

Anastomosis, Surgical↗

PubMed1993

[Subclass distribution of IgG and IgA antibodies in summer-type hypersensitivity pneumonitis].

The present study was undertaken to determine the most specific of the 3 serotypes of Trichosporon cutaneum responsible for summer type hypersensitivity pneumonitis and to elucidate the subclass distribution of the antibody response, which is partly dependent on the nature of the causative antigen. Western blot analysis revealed that serotype II (TIMM 1318) is the most specific antigen for summer type hypersensitivity pneumonitis. The subclass distributions of anti-Trichosporon cutaneum IgG antibodies and IgA antibodies in sera and bronchoalveolar lavage fluids (BALF) from 13 patients with summer type hypersensitivity pneumonitis and 10 normal volunteers were measured by biotin-avidin-linked immunosorbent assay. The results were as follows, (1) high levels of IgA2 antibodies were found in BALF, but minute amounts in sera, (2) IgG1 antibodies were the predominant subclass in sera and BALF, (3) three out of 13 cases showed high levels of IgG3 antibodies in sera and BALF associated with low levels of IgG1 antibodies, (4) IgA1 antibodies were found in both sera and BALF. (5) the levels of all antibody subclasses were higher in BALF than in sera. The subclass distributions suggest that the protein components of Trichosporon cutaneum are predominantly immunogen, although polysaccharides may participate as an antigen in the respiratory tract.

Alveolitis, Extrinsic Allergic↗

PubMed1993

Cardioplegic effect of University of Wisconsin solution on hypothermic ischemia of rat myocardium assessed by mitochondrial oxidative phosphorylation.

The effectiveness of the University of Wisconsin solution and the Collins' M solution for preservation of rat hearts was compared by examining histologic appearance, tissue water content, and mitochondrial respiratory functions after prolonged hypothermic storage and subsequent heterotopic transplantation. Survival of transplanted hearts after 5 days of reperfusion was markedly lowered by storage in Collins' M solution for 15 hours. Hearts stored in University of Wisconsin solution for 10 hours showed no increase in myocardial necrosis after 5 days of reperfusion, whereas hearts stored in University of Wisconsin solution for 15 hours and Collins' M solution for 10 and 15 hours showed a significant increase in tissue necrosis. University of Wisconsin solution reduced tissue swelling during hypothermic storage, whereas Collins' M solution did not cause such reduction. The yield of mitochondrial protein after reperfusion was significantly decreased by storage in either solution, especially after 15 hours in Collins' M solution. Mitochondrial oxidative phosphorylation was significantly inhibited by storage, especially by storage in Collins' M solution and subsequent reperfusion. These results indicate that myocardial injury, after prolonged ischemia and reperfusion, results in a decrease in functionally and structurally intact mitochondria that is dependent on preservation conditions. University of Wisconsin solution protects isolated hearts against ischemia and reperfusion injury possibly by preventing cellular and mitochondrial deterioration.

Adenosine↗

PubMed1993

Establishment of two distinct human hepatocellular carcinoma cell lines from a single nodule showing clonal dedifferentiation of cancer cells.

Hepatocellular carcinomas often contain tumor cells of more than one histological grade. The clonal relationship and biological behavior of hepatocellular carcinoma cells in histologically heterogeneous areas have not been fully explored. We established two distinct human hepatocellular carcinoma cell lines (HAK-1A and 1B) from a single nodule showing a three-layered structure with a different histological grade in each layer. Morphologically, HAK-1A and 1B resembled well-differentiated hepatocellular carcinoma cells in the outer layer of the original tumor and poorly differentiated ones in the inner layer, respectively. HAK-1B appeared less differentiated morphologically and more aggressive biologically than HAK-1A; HAK-1B had a shorter doubling time, higher tumorigenicity and an aneuploid DNA index. Chromosome analysis revealed many different abnormalities in the two cell lines, in which, however, two identical structural abnormalities (2q+ and 17p+) were identified. Moreover, sequence analysis of the p53 gene showed identical mutations at codon 242 in both cell lines. These findings suggest that the two cell lines are of clonal origin and that hepatocellular carcinomas consisting of cancerous tissues of more than one histological grade may reflect clonal dedifferentiation in the tumor. Furthermore, we predict that a clonal, morphologically less differentiated subpopulation such as HAK-1B is more aggressive in proliferation and may be closely related to subsequent tumor progression in hepatocellular carcinoma.

Base Sequence↗

PubMed1992

Genomic structure of the human caldesmon gene.

The high molecular weight caldesmon (h-CaD) is predominantly expressed in smooth muscles, whereas the low molecular weight caldesmon (l-CaD) is widely distributed in nonmuscle tissues and cells. The changes in CaD isoform expression are closely correlated with the phenotypic modulation of smooth muscle cells. During a search for isoform diversity of human CaDs, l-CaD cDNAs were cloned from HeLa S3 cells. HeLa l-CaD I is composed of 558 amino acids, whereas 26 amino acids (residues 202-227 for HeLa l-CaD I) are deleted in HeLa l-CaD II. The short amino-terminal sequence of HeLa l-CaDs is different from that of fibroblast (WI-38) l-CaD II and human aorta h-CaD. We have also identified WI-38 l-CaD I, which contains a 26-amino acid insertion relative to WI-38 l-CaD II. To reveal the molecular events of the expressional regulation of the CaD isoforms, the genomic structure of the human CaD gene was determined. The human CaD gene is composed of 14 exons and was mapped to a single locus, 7q33-q34. The 26-amino acid insertion is encoded in exon 4 and is specifically spliced in the mRNAs for both h-CaD and l-CaDs I. Exon 3 is the exon that encodes the central repeating domain specific to h-CaD (residues 208-436) together with the common domain in all CaD (residues 73-207 for h-CaD and WI-38 l-CaDs, and residues 68-201 for HeLa l-CaDs). The regulation of h- and l-CaD expression is thought to depend on selection of the two 5' splice sites within exon 3. Thus, the change in expression between l-CaD and h-CaD might be caused by this splicing pathway.

Alternative Splicing↗

PubMed1992

A cholangiocellular carcinoma nude mouse strain showing histologic alteration from adenocarcinoma to squamous cell carcinoma.

BACKGROUND: Adenosquamous carcinoma and squamous cell carcinoma (SCC) occur rarely in the liver compared with adenocarcinoma, and the histogenesis and biologic behaviors of these tumors remain unknown. The authors addressed these issues in the current article. METHODS: A specimen aseptically obtained from the surgically resected cholangiocellular carcinoma (CCC) was cut into pieces and inoculated into the back of a nude mouse, bilaterally. The developed tumors were resected and serially transplanted into nude mice. The morphologic features and growth kinetics of the nude mouse tumors at different passages were compared. RESULTS: The authors established a new human CCC nude mouse strain, designated nuKMC-2, from a 64-year-old woman. The original tumor of the patient showed the features of moderately differentiated tubular adenocarcinoma with small sheet-like arrangement of polygonal cells. The initial tumor developed in a nude mouse showed morphologic features similar to the original tumor. With the serial transplantation to nude mice, the components of tubular adenocarcinoma diminished, and all of the nuKMC-2 was replaced by SCC. Doubling times of nuKMC-2 at the 5th and 11th passages were 9.9 and 7.4 days, respectively, which suggested that the tumor with squamous components were more aggressive biologically than the adenocarcinoma. CONCLUSIONS: The results suggested that adenosquamous carcinoma might be a transitional form from adenocarcinoma to SCC and that some of the primary hepatic SCC might originate from adenocarcinomas.

Adenocarcinoma↗

PubMed1992

Distribution of the glucose transporters in human brain tumors.

In the present study, we have investigated the expression of both the erythrocyte-type (GLUT1) and the brain-type (GLUT3) glucose transporter isoforms in primary human brain tumors. In situ hybridization made it possible to localize and semiquantify both GLUT1 and GLUT3 mRNAs of individual cells in all 18 samples examined. More signals for GLUT3 mRNA than for GLUT1 mRNA were found over astrocytoma cells, while the reverse was the case in all 6 meningiomas. In astrocytomas, for both mRNAs, the density of silver grains over tumor cells was well correlated with the malignancy of the cells. This correlation was, as was also confirmed by Northern blot analysis, more marked with GLUT3 mRNA than with GLUT1 mRNA. In 2 of 5 anaplastic astrocytomas and in all 3 glioblastomas, numerous tumor cells with large amounts of both mRNAs tended to surround the perivascular regions. "Tumor vessels" with endothelial proliferation, an almost pathognomonic feature of glioblastomas, expressed much GLUT3 mRNA but no significant GLUT1 mRNA, while a single- or a few-layered capillary endothelium expressed much GLUT1 mRNA. The distribution of both mRNAs was in good accordance with that of both proteins. Our results suggest that the expression of both glucose transporter isoforms may contribute to the maintenance of human brain tumors and that the expression of the GLUT3 isoform may be closely related to the malignant change of astrocytomas and particularly related to the aberrant neovascularization which accompanies glioblastomas.

Astrocytoma↗

PubMed1992

Cold exposure increases glucose utilization and glucose transporter expression in brown adipose tissue.

When rats were exposed to a cold environment (4 degrees C) for 10 days, tissue glucose utilization was increased in brown adipose tissue (BAT), a tissue specified for non-shivering thermogenesis, but not in skeletal muscle. Cold exposure also caused an increase in the amount of GLUT4, an isoform of glucose transporters expressed in insulin-sensitive tissues, in parallel with an increased cellular level of GLUT4 mRNA. In contrast to BAT, no significant effect of cold exposure was found in skeletal muscle. The results suggest the cold-induced increase in glucose utilization by BAT is attributable, at least in part, to the increased expression of GLUT4.

Acclimatization↗