Biomedical subjects
N Kono
Publications and source records attributed to N Kono.
Expression of mouse phosphofructokinase-M gene alternative transcripts: evidence for the conserved two-promoter system.
Molecular cloning of the 5' part of mouse phosphofructokinase-M cDNA was performed. In the 46 cDNA clones isolated, there were two classes of 5' untranslated sequences. One had an EcoRI site within its 5' untranslated sequence. This showed 83.0% similarity with human type B mRNA for phosphofructokinase-M. The other lacked an EcoRI site, showing 92.9% similarity with human type C mRNA. Using the reverse-transcription PCR technique, we found that the transcript with an EcoRI site was exclusively expressed in cardiac and skeletal muscles, while that without an EcoRI site was expressed in all the mouse tissues examined. The results suggested that the mouse phosphofructokinase-M gene was transcribed through alternative splicing by the multiple promoters. This transcription mechanism was considered to be evolutionarily conserved. The level of phosphofructokinase-M gene expression in mouse cardiac and skeletal muscles decreased in the ketotic diabetic state. Although the regulatory mechanism and the physiological significance are not fully known, this would indicate that phosphofructokinase-M gene transcripts are affected during the diabetic state.
A new variant of muscle phosphofructokinase deficiency in a Japanese case with abnormal RNA splicing.
A genetic defect was investigated in a newly diagnosed Japanese case with muscle type phosphofructokinase (PFK-M) deficiency. Polymerase chain reaction (PCR) amplification of patient cDNA revealed an in-frame truncation of 165 bases. This was compatible to the complete deletion of exon 19. The rest of the sequence was identical to that of the normal PFK-M cDNA. Sequencing of PCR amplified genomic DNA of the patient revealed a point mutation from G to A at the 5' donor site of intron 19. This mutation resulted in the skipping of exon 19 in the patient mRNA. Homozygosity of this patient was confirmed by allele specific amplification of the genomic DNA. Donor mutations in intron 15 and intron 5 associated with different splicing errors were previously reported to cause this disease. Thus, the human PFK-M gene mutations are heterogeneous, however, the donor mutations and splicing errors would represent one of the frequent causes of this disease.
Effects of glucagon on urinary excretion of urea and on plasma ammonia level in argininosuccinate synthetase deficiency.
Glucagon, a potent inducer of urea cycle enzymes, was administered subcutaneously, at a dose of 0.5 mg once a day, for 7 days to two citrullinemic patients. During this period, plasma NH3 levels in case 1 decreased significantly (P < 0.05 compared to levels before administration) and daily urinary excretion of urea N increased significantly (P < 0.05). For 1 week after the cessation of administration, the daily urinary excretion of urea N was significantly higher than the level before administration (P < 0.05), the plasma citrulline level during glucagon administration was lower than that before administration. In case 2, glucagon administration also decreased the plasma NH3 level (although the decrease was not statistically significant), and significantly increased daily urinary excretion of urea N (P < 0.05 compared to levels before administration). For 1 week after the cessation of glucagon administration the plasma citrulline level was significantly lower than that before administration (P < 0.05). These results indicate that glucagon significantly increases the urinary excretion of urea in the late onset form of argininosuccinate synthetase deficiency and that it may also decrease plasma NH3 levels in some patients with the deficiency.
Impaired ketogenesis in patients with adult-type citrullinemia.
BACKGROUND/AIMS: To clarify the mechanism causing fatty liver in adult-type citrullinemia, the effect of fasting on blood levels of free fatty acids, triglycerides, and ketone bodies was investigated in two cases. METHODS: Blood and urine samples were collected from two patients and healthy volunteers 12, 15, 17, 21.5, and 24 hours after their last meal. RESULTS: During 24-hour fasting free fatty acid concentrations increased in both cases to the concentrations found in the healthy volunteers. The levels of blood ketone bodies (beta-hydroxybutyrate and acetoacetate) were markedly suppressed throughout the fasting test without any increase in urinary excretion of ketone bodies or organic acids in both cases when plasma citrulline concentrations were more than 10-fold higher than in controls. Serum triglyceride concentrations in case 1 paradoxically increased from 185 mg/dL to 294 mg/dL during 24-hour fasting when the citrulline concentration was extremely high. When hemodialysis was performed and plasma citrulline consequently decreased to near the normal level in case 1, levels of both serum triglycerides and blood ketone bodies responded normally to 24-hour fasting. CONCLUSIONS: These data suggest that ketogenesis was impaired in adult-type citrullinemia.
Influence of daily drinking habits on ethanol-induced hyperuricemia.
We examined the influence of alcohol drinking habits on the serum uric acid level after the ingestion of a small amount of ethanol. Subjects were divided into two groups according to their alcohol drinking habits--regular drinkers, who consume more than 60 g ethanol every day, and nondrinkers/occasional drinkers, who consume less than 20 g ethanol occasionally. Drinking 0.5 g ethanol/kg increased serum uric acid levels in regular drinkers by 52.6 +/- 26.3 mumol/L (0.8 +/- 0.4 mg/dL), whereas it did not in nondrinkers/occasional drinkers. Urinary excretion of uric acid was unaltered in both groups. Hypoxanthine and xanthine in both plasma and urine and serum acetate were increased more in regular drinkers than in nondrinkers/occasional drinkers. Accelerated adenine nucleotide degradation secondary to enhanced ethanol oxidation likely explains the ethanol-induced hyperuricemia in regular drinkers.
Occurrence of IDDM during interferon therapy for chronic viral hepatitis.
We report a case of IDDM which occurred during interferon therapy for chronic hepatitis. A 31-year-old man intermittently received 2.5 x 10(8) units of alpha-IFN and 1 x 10(8) units of beta-IFN for treatment of chronic viral hepatitis type B. Four years after the beginning of IFN therapy, he acutely developed moderate hyperglycemia and severe ketonuria with positive islet cell antibody, and then 28 units/day of insulin injection was started. After the start of insulin therapy, there was a remission period for about 3 years but insulin-dependency recurred thereafter. The clinical course of this case indicates that IFN therapy precedes IDDM. During and after IFN therapy we should consider the possibility of occurrence of IDDM as well as other autoimmune diseases and observe the clinical course carefully.
Neoexpression of Lewis Y antigen is a sensitive phenotypic change of the damaged intrahepatic bile ducts.
We examined the expression of Lewis antigens, particularly Lewis Y, on the intrahepatic biliary epithelial cells in normal livers and various hepatobiliary diseases with immunohistochemical and immunoelectron microscopic methods. In normal livers, Lewis Y was consistently and generally negative in the bile ductules and small bile ducts, respectively. This antigen was frequently and strongly expressed on these ducts and ductules showing variable pathological changes such as necroinflammation and proliferation in a majority of hepatobiliary diseases independent on their etiology, whereas a majority of normal-appearing bile ducts and ductules in these pathological conditions were negative. Immunoelectron microscopically, gold particles suggesting the presence of Lewis Y were demonstrated on microvilli facing the biliary lumen, lateral cell membranes, secretory granules and Golgi apparatus of abnormal biliary epithelial cells in various hepatobiliary diseases. These data suggest that neoexpression of Lewis Y antigen is a highly sensitive, nonspecific phenotypic change of carbohydrate residues occurring in the abnormal biliary epithelial cells in various hepatobiliary diseases.
Membranous expression of Lewis Y antigen in clustered hepatocytes in chronic viral, autoimmune, and alcoholic liver diseases but not in biliary diseases.
The expression of Lewis Y antigen (a blood group-related antigen containing type 2 chain) in hepatocytes was examined immunohistochemically, using the monoclonal antibody F-3, in a total of 530 liver specimens consisting of normal livers and various hepatobiliary diseased livers. Lewis Y was rarely expressed in the hepatocytes in histologically normal livers (20 cases) or in livers from patients with nonspecific reactive change or chronic persistent hepatitis, in viral livers (19 cases), autoimmune etiology livers (3 cases), or acute hepatitis-like change of autoimmune etiology livers (7 cases). In chronic active hepatitis of viral (132 cases) and autoimmune etiology livers (20 cases) with or without cirrhosis, the incidence of membranous expression of Lewis Y in clustered hepatocytes of viral and autoimmune etiology livers was 21 and 0% of mild chronic active hepatitis; 69 and 25% of moderate degree; 85 and 50% of severe degree; and 87 and 100% of cirrhosis, respectively. In alcoholic liver disease (27 cases), the incidence of membranous expression of Lewis Y in clustered hepatocytes was 18, 75, and 100% in mild fibrosis, moderate fibrosis, and cirrhosis, respectively. Such membranous expression of Lewis Y was not found in the early or late stages of the biliary diseases examined, primary biliary cirrhosis (226 cases), primary sclerosing cholangitis (8 cases), or extrahepatic biliary obstruction (22 cases).(ABSTRACT TRUNCATED AT 250 WORDS)
Clinical evaluation of biosynthetic glucagon treatment for recovery from hypoglycemia developed in diabetic patients. The GL-G Hypoglycemia Study Group.
Biosynthetic glucagon (GL-G) produced by recombinant DNA technology with transformed yeast strains is already available for clinical use. We studied the effects of 1 mg GL-G injection on plasma glucose level and hypoglycemic symptoms in 38 diabetic patients treated with insulin or oral hypoglycemic agents during spontaneous hypoglycemic episodes. In both intramuscularly and intravenously administered GL-G groups, plasma glucose significantly increased from 58.1 +/- 11.4 to 113.2 +/- 6.9 mg/dl (i.m., n = 17, P < 0.01) and from 76.4 +/- 4.4 to 125.7 +/- 5.9 mg/dl (i.v., n = 15, P < 0.01), respectively 20 min after the administration and the symptoms due to hypoglycemia subsided promptly after the injection of GL-G in 27 cases. The hyperglycemic effect of intramuscularly injected GL-G was more potent and long-standing than when intravenously injected, particularly in insulin-dependent diabetic (IDDM) patients. Neither significant changes of antibody levels against yeast proteins nor serious adverse effects were observed after GL-G administration. Biosynthetic glucagon is safe and useful for the treatment of hypoglycemia developing in diabetic patients.
Histological changes of the liver in experimental graft-versus-host disease across minor histocompatibility barriers. VII. A light and electron microscopic study of the large bile duct.
Although morphologic changes of the intrahepatic bile ducts in graft-versus-host disease (GVHD) have been well studied, those of the large extrahepatic bile ducts in the porta hepatis or common bile ducts have not been so well elucidated. In the present study, pathologic changes of the extrahepatic bile ducts in experimental mouse GVHD across minor histocompatibilty barriers were examined up to 14 months after transplantation. Mononuclear cell infiltration was most striking around 2 weeks after transplantation. Although it gradually decreased, infiltration persisted during the entire period of observation. Fibrous thickening and sclerosis of the bile duct wall continued over time following transplantation, especially 3 months after transplantation. The appearance was similar to sclerosing cholangitis, but obliteration of the lumen was not demonstrated. Electron microscopically, the bile duct epithelial layer was frequently infiltrated by lymphocytes, and often accompanied by polymorphonuclear leukocytes, monocytes, and rarely by plasma cells. The epithelial cells in close contact with and in the vicinity of these cells showed a variety of degenerative changes. These results suggest that not only the interlobular and/or small bile ducts but also the large hilar and extrahepatic bile ducts are involved in hepatic GVHD, and thus bile duct injury in GVHD may occur along the full length of the biliary tree.
Glycogenosis type V (McArdle's disease) with hyperuricemia. A case report and clinical investigation.
A 28-year-old male with glycogenosis type V associated with continuous hyperuricemia during mild daily activities is reported. An aerobic exercise test using a bicycle ergometer revealed that purine metabolites, i.e., ammonia, inosine, hypoxanthine and xanthine, were transiently increased by the exercise and that a subsequent increment in uric acid continued until the following day. The accelerated purine degradation by the muscle exercise was thus shown to be able to cause the overt hyperuricemia in a patient with glycogenosis type V. Therapeutic use of fructose for glycogenosis was disappointing due to fructose-induced hyperuricemia. A search for myogenic hyperuricemia is essential for therapeutic trials.
The inhibitory effect of noradrenaline on thyrotrophin-stimulated 3,5,3'-tri-iodothyronine and thyroxine release is mediated through a Ca(2+)-dependent process in the thyroid gland of the mouse.
We examined the effect of noradrenaline on the release of 3,5,3'-tri-iodothyronine (T3) and thyroxine (T4) from perifused mouse thyroid. Noradrenaline suppressed the thyrotrophin (TSH)-stimulated release of T3 and T4. The addition of prazosin, which is a specific alpha 1 antagonist, or the depletion of Ca2+ from the perifusion buffer completely abolished the inhibitory effect of noradrenaline on TSH-stimulated T3 and T4 release. Noradrenaline did not inhibit TSH-stimulated cyclic adenosine 3',5'-monophosphate (cAMP) release in the presence of 3-isobutyl-1-methylxanthine (IBMX), which inhibits both cAMP-specific and calmodulin-sensitive phosphodiesterases. Noradrenaline significantly suppressed the TSH-stimulated release of T3 and T4 in the presence of IBMX. These results suggest that the inhibitory effect of noradrenaline on TSH-stimulated T3 and T4 release is not mediated through a cAMP-dependent process or the activation of a calmodulin-sensitive phosphodiesterase, and that this inhibition is mediated through a Ca(2+)-dependent process regulated by the alpha 1-adrenergic system in the mouse thyroid.
Overexpression of HLA class I antigen reduces insulin secretion in pancreatic beta cells (RINM5F): evidence for a non-immune mechanism.
Our recent observation indicated that overexpression of HLA-class I antigen on pancreatic beta cells is one of the features of insulin-dependent diabetes mellitus (IDDM). To analyze the effect of class I antigen overexpression, we have introduced human HLA class I (HLA-Cw3) gene into rat pancreatic beta cell lines, RINm5F. Several stable transformants with various levels of surface expression of class I antigens have been cloned. The insulin secretion of these transfectants was analyzed to evaluate the functions of beta cells. Highly negative correlation between the level of insulin secretion and that of class I expression (correlation coefficiency: r = 0.89) has been observed. These data suggest that the overexpression of HLA class I antigen itself may impair pancreatic beta cells through a nonimmune mechanism.
[A case of severe interstitial pneumonia probably due to Chlamydia pneumoniae].
A 64-year-old male was admitted to our hospital with dyspnea and high fever. The patient had a relative bradycardia and severe hypoxemia. Velcr rales were heard throughout the entire lung fields. Leucocytosis was absent. Chest X-ray showed bilateral diffuse reticular shadows. Corticosteroid pulse therapy and minocycline were introduced on the suspicion of either idiopathic interstitial pneumonia or Chlamydial pneumonia. Subsequently, his symptoms gradually improved. Although the patient had no history of exposure to birds, the titer of complement fixation test for Chlamydia was 1:32 during the acute illness. Microplate immunofluorescence antibody technique proved infection with Chlamydia pneumoniae. We consider this is a rare case of severe pneumonia caused by C. pneumoniae.
[Immunohistological evaluation of parathyroid hormone-related protein in breast cancer with and without calcification on mammography].
PTHrP is the main factor of humoral hypercalcemia of malignancy. PTHrP produces the same effect on renal and osteoblast membrane in vitro and on calcium and inorganic phosphate fluxes in vivo as human PTH. Physiologically, PTHrP is produced by rat mammary tissue during lactation. It is suggested that PTHrP correlates to the metabolism of calcium in the mammary gland. Using anti-PHTrP (1-34) monoclonal antibody 4B3, we investigated the correlation of PTHrP and calcification in breast cancer. All the breast cancers with calcification on mammography showed positive immunostaining. Most cases without calcification, on the other hand, showed negative. Positive PTHrP staining was not related to the any clinical parameter. It is suspected that PTHrP is also one of the main factors of calcification in breast cancer.
Succinylated wheat germ agglutinin lectin binding in intrahepatic vessels. A new histochemical tool.
Succinylated wheat germ agglutinin, specified by the amino sugar beta(4)-N-acetylglucosamine, bound frequently to the endothelial cells of the hepatic arterial branches and small vessels of the peribiliary capillary plexus, while it did not bind to the endothelial cells of venous vessels such as portal vein branches and hepatic venous radicles, nor to lymphatic vessels. Sinusoidal endothelial cells were also negative for succinylated wheat germ agglutinin. Proliferating small vessels in the enlarged portal tracts and fibrous septa in patients with extrahepatic biliary obstruction or chronic active hepatitis with or without cirrhosis tended to be positive for succinylated wheat germ agglutinin. Such findings have not been previously reported, to the best of our knowledge. Thus, succinylated wheat germ agglutinin may be a new and useful histochemical tool in routinely processed tissue sections to discriminate intrahepatic vessels into several categories, particularly into two categories (arterial and other vessels), in normal as well as diseased livers.
An alternate nonisotopic technique of PCR-mediated allele-specific oligonucleotide analysis for the detection of a point mutation.
We report a simple protocol for the allele analysis of a point mutation using polymerase chain reaction. Conditions have been determined to use probes prepared for the conventional allele-specific oligonucleotide hybridization method directly. After amplification of the genomic region containing the mutation site, the nested polymerase chain reaction was performed using an allele-specific oligonucleotide probe as one side of the primer. Specificity of the amplification was achieved by decreasing the primer concentration in a two segment thermal cycling pattern. This protocol does not require additional special primers and an allelic mutation can be determined non-isotopically.