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Biomedical subjects

T Harano

Publications and source records attributed to T Harano.

At least 55 records · Page 3Linked to original sources
PubMed1995

[Hb M-Iwate [alpha 87 (F8) His-->Tyr]: analysis of the genomic DNA and biosynthesis].

Hb M-Iwate [alpha 87 (F8) His-->Tyr] was identified as the cause of cyanosis in a 21-year-old Japanese female. Amplification and sequencing of the alpha 2- and alpha 1-genes demonstrated the mutation CD87 CAC (His)-->TAC (Tyr) in the alpha 2-gene. Analysis of the in vitro globin biosynthesis in the reticulocytes disclosed a well-balanced beta/alpha synthetic ratio of 1.04 but an unexpectedly low alpha M/total alpha. Although the cause of the lowered alpha M-globin biosynthesis is not yet clear, it might be related to a defect in chain assembly rather than to a modified stability or a reduced amount of the abnormal alpha-globin mRNA.

Adult↗
PubMed1995

[The first case in Japan of unstable hemoglobin, Hb Buenos Aires [beta 85 (F1) Phe-->Ser], with parvovirus B19 infection (first case in Japan)].

A 9-year-old girl was admitted to Mie University Hospital June 25, 1992, complaining of fever, skin rash and pallor. Physical examination revealed anemia and hepatosplenomegaly. Laboratory findings showed normocytic normochromic anemia, increased reticulocyte counts and remarkably decreased haptoglobin level. Red blood cells had no morphological abnormality. Bone marrow examination showed erythroid hyperplasia without abnormal cells. Hemoglobin electrophoresis showed an abnormal band. The amino acid structure and sequence of the abnormal hemoglobin was determined to be an unstable hemoglobin, Hb Buenos Aires [beta 85 (F1) Phe-->Ser]. Sequence of genomic DNA and cDNA was compatible to Hb Buenos Aires. Parvovirus B19 infection was thought to have caused severe anemia due to hemolytic crisis in this patient because its IgM antibody was positive on admission. She recovered soon without any treatment and has been followed in the outpatient clinic. Her parents and brother showed no hemoglobin abnormality.

Base Sequence↗
PubMed1994

Phorbol ester-induced activation of a membrane-bound candidate pro-transforming growth factor-alpha processing enzyme.

Transforming growth factor-alpha (TGF-alpha) is synthesized and transported to the cell surface as a membrane-anchored precursor (proTGF-alpha) that is converted to the soluble form by proteolytic cleavage. ProTGF-alpha cleavage is activated in response to tumor-promoting phorbol ester or to calcium ionophore. Mechanism(s) controlling conversion of the membrane-anchored precursor to the soluble TGF-alpha are unknown, and the responsible protease has not been identified. Using the fluorogenic substrate succinyl-Ala-Ala-Ala-4-methylcoumaryl-7-amide (Suc-Ala-Ala-Ala-MCA), containing the sequence similar to the cleavage sites for proTGF-alpha processing, we identified a putative candidate proTGF-alpha-converting enzyme in the membrane fractions of Chinese hamster ovary (CHO) cells. The enzyme activity was about 5-6-fold increased by exposure of the cells with phorbol ester or with calcium ionophore. The enzyme activity was released from the cells by trypsin added exogenously; hence, the activity probably locates on the outer surface of the cell membrane. The enzyme was partially purified from membranes of phorbol ester-treated CHO cells. The molecular mass of the enzyme was estimated to be about 84 kDa by gel filtration analysis. Inhibitor profile of the enzyme, including inhibition by serine protease inhibitors and no inhibition by elastatinal, coincides with that previously reported for proTGF-alpha cleavage activity on CHO cells. These findings suggest that the enzyme is a processing protease involved in the cleavage of proTGF-alpha and that induction of proTGF-alpha conversion by phorbol ester or by calcium ionophore can be attributed to activation of the processing protease. In the cell-free reconstitution system, the membrane-bound Suc-Ala-Ala-Ala-MCA-hydrolyzing enzyme from CHO cells was also activated by phorbol ester in the presence of the soluble fraction, ATP, and vanadate. Requirement of vanadate, an inhibitor for protein phosphatases, for activation of the enzyme in this system suggests that phosphorylation-dephosphorylation probably plays a key role in the regulated cleavage of proTGF-alpha.

Amino Acid Sequence↗
PubMed1994

Purification and characterization of hepatocyte growth factor (HGF)-converting enzyme: activation of pro-HGF.

Hepatocyte growth factor (HGF) is a heterodimer protein, derived from an inactive single-chain precursor (pro-HGF) by the proteolytic cleavage at Arg-Val site. Using a fluorogenic substrate Ac-Lys-Thr-Lys-Gln-Leu-Arg-MCA corresponding to the sequence around the cleavage site of pro-HGF, HGF-converting enzyme was purified from fetal bovine serum. The enzyme is a heterodimer molecule with an apparent molecular weight of about 90-kDa and is composed of a 65-kDa heavy-chain and a 32-kDa light-chain. The enzyme belongs to the serine-protease family and has an optimal pH around 8. The enzyme preferentially cleaved MCA-substrates containing the processing site of pro-HGF. The purified enzyme converted pro-HGF to a two-chain mature form of HGF. The enzyme-treated pro-HGF had mitogenic activity on primary cultured hepatocytes. Thus, the enzyme is likely to be involved in pro-HGF activation in vivo. The enzyme activity in rat serum was 9-fold higher than that in the plasma. This, together with the heterodimeric structure of the enzyme, suggests that the HGF-converting enzyme is activated by another protease in response to a trigger such as blood coagulation or tissue injury.

Amino Acid Sequence↗
PubMed1994

Hemolytic properties of Ca(2+)-treated human erythrocytes under hydrostatic pressure.

The effect of intracellular Ca2+ on high pressure-induced hemolysis of human erythrocytes was examined. Red cells were incubated with Ca2+ (0.01-1 mM) in the presence of ionophore A23187. The Ca(2+)-loaded cells were subjected to a pressure of 200 mPa. Treatment with 0.1 mM Ca2+ had the greatest suppressive effect on the hemolysis. On removal of intracellular Ca2+, red cells showed a morphological change from echinocytes to normal discocytes but the hemolysis remained unaltered. Measurement of intracellular K+ and viscosity demonstrated that the suppressive effect of Ca2+ on the hemolysis is irreversible and is largely associated with the increase of intracellular viscosity induced by K+ efflux.

Blood Viscosity↗
PubMed1994

Hemoglobin Bethesda causing polycythemia in a Japanese family.

A family with Hemoglobin Bethesda is reported. A 23-year-old man was hospitalized for the evaluation of polycythemia. Analysis of hemoglobin using high pressure liquid chromatography showed the presence of hemoglobinopathy. Separation of globin into alpha and beta chains revealed approximately 50% of the beta chain to be abnormal. Analysis of the DNA sequence of the beta chain gene identified Hb Bethesda. The family study disclosed that his father and sister also had the same hemoglobinopathy. This case is the first report of Hb Bethesda in Japan.

Adult↗
PubMed1993

A splicing mutation in the alpha 5(IV) collagen gene of a family with Alport's syndrome.

DNA sequence analysis of the alpha 5(IV) collagen chain gene (COL4A5) was carried out between exon 47 and 51, which encode the noncollagenous (NC) domain, in eight Japanese families with Alport's syndrome. In one family with X-linked inheritance of the disease, a point mutation (G to C) was found at the 3' end of exon 49 in the COL4A5. This mutation converted the codon of a conserved methionine-1601 to the codon for isoleucine, and also altered the normal splicing process. The polymerase chain reaction (PCR) product amplified between exons 47 and 51 of cDNA in the affected male (hemizygote) of this family contained four fragments with various molecular weights, whereas that of a normal control contained one with the expected molecular weight. Sequence analysis of the PCR fragments of the male patient revealed various types of alternative splicing between the exons, reflecting the various sizes of PCR fragments. The PCR amplified product of the cDNA of the affected female (heterozygote), on the other hand, contained a fragment with the same molecular weight as the normal control. Sequence analysis of the PCR fragments of her cDNA revealed normal splicing and no point mutation at the 3' end of exon 49. These findings indicate that this point mutation at the consensus sequence not only converted the codon but also altered the splicing between these exons encoding the NC domain of the COL4A5. Resulting in missense of the alpha 5(IV) chain, changing a large portion of the carboxyl terminal crosslinking NC domain, this mutation can alter the normal structure of the type IV collagen network.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Effects of drugs, salts, and phospholipid vesicles on hemoglobin release from hydrostatic pressure-treated human erythrocytes.

When human erythrocytes subjected to a pressure of 2.0 kbar were incubated at 0 degree C and atmospheric pressure, hemoglobin was released from the membrane. Effects of drugs, salts, and phospholipid vesicles on hemoglobin release were examined. The hemoglobin release was suppressed by the addition of amphiphathic drugs such as chlorpromazine, trifluoperazine, tetracaine, indomethacin, and phenylbutazone or by a hypertonic condition. The suppressive effect induced by these drugs or hypertonic buffer was enhanced by the addition of aminophospholipid vesicles containing phosphatidylserine (PS) and/or phosphatidylethanolamine (PE) but decreased by vesicles composed of phosphatidylcholine (PC) and sphingomyelin. In the isotonic buffer without these drugs, such effects of vesicles were small. The suppressive effects of PS and PE were decreased by chemical modification of carboxylic groups and amino groups with 1-ethyl-3-(3-dimethylaminopropyl)carbodimide and 2,4,6-trinitrobenzenesulfonate, respectively. The size of vesicles as well as phospholipid composition was also an important factor in the suppression of hemoglobin release. The ESR spectrum of pressure-treated membrane spin-labeled with a maleimide was changed by PC vesicles but not by PS vesicles. These results indicate that the resealing of pressure-induced membrane holes by amphipathic drugs or hypertonic medium is synergistic with aminophospholipid vesicles and the hole size is affected by the vesicle-membrane protein interaction.

Chlorpromazine↗
PubMed1993

Beta 0-thalassemia trait (IVS-I-1 G-->T) in a Japanese family.

Three subjects in a family with microcytic and hypochromic anemia were studied; red blood cell morphology indicated aniso-poikilocytosis and hypochromasia. Target and tear-drop cells were also noted. In all three cases evaluated, there was an increase in HbA2 levels and a decline in the beta/alpha synthesis ratio. Direct cloning and DNA sequencing identified a point mutation (G-->T) at position 1 of intervening sequence I. The resulting reduction of beta-globin chain synthesis is considered to give rise to beta 0-thalassemia phenotype. This point mutation is to our knowledge, the first case in Japan.

Base Sequence↗
PubMed1992

Beta(+)-thalassemia with hemochromatosis.

A 64-year-old man was admitted due to ascites. Laboratory data showed hemoglobin 6.7 g/dl, mean corpuscular volume 82 fl, and ferritin 2,360 ng/ml. Liver biopsy showed hemochromatosis. The diagnosis of beta-thalassemia was suggested by a decreased ratio of beta/alpha-globin synthesis in vitro (0.26). Cloning of the beta-globin gene showed A-to-G mutation in the first base of the ATA box. He was confirmed to be homozygous for this specific allele by beta-gene complex analysis and analysis of Southern blot hybridization of the alpha- and beta-globin genes. His two sons were confirmed to be heterozygous for this allele.

Adult↗
PubMed1992

Hemoglobin Andrew-Minneapolis (beta 144 (HCl) lysine----asparagine) in a Japanese family.

Hemoglobin Andrew-Minneapolis, an abnormal hemoglobin with an asparagine residue substituted for a lysine at position 144 of the beta-globulin chains, was identified in three members of two generations in a Japanese family. The carriers of hemoglobin Andrew-Minneapolis showed false high levels of hemoglobin A1c, as measured by the standard cation exchange high performance liquid chromatography, and a moderate tendency for erythrocytosis. This family is the first report of this abnormal hemoglobin in Japan.

Adult↗
PubMed1992

Hb Kanagawa [alpha 40(C5)Lys----Met]: a new alpha chain variant with an increased oxygen affinity.

An abnormal hemoglobin was suspected in a 70-year-old Japanese male with cerebral infarction and erythremia with high performance liquid chromatography assay of Hb A1c. The hemoglobin variant migrated to the anode more rapidly than Hb A. Structure determination studies, including amino acid analysis of the abnormal peptide and DNA sequencing of a partially cloned alpha-globin gene, demonstrated that it is a new hemoglobin variant which has been named Hb Kanagawa [alpha 40(C5)Lys----Met]. This variant showed an increased oxygen affinity, decreased heme-heme interaction, and a lowered 2,3-diphosphoglycerate effect relative to normal.

Aged↗
PubMed1991

Hb Isehara (or Hb Redondo) [beta 92 (F8) His----Asn]: an unstable variant with a proximal histidine substitution at the heme contact.

A 50-year-old Japanese female patient was found to have hemolytic anemia. Isoelectrofocusing of her hemolysate revealed two abnormal hemoglobin bands, one of which was very close to the Hb A2 band, and the other between the Hb A2 and Hb F bands. CM-cellulose column chromatography of the globin prepared from the abnormal hemoglobin showed that the abnormal chain eluted faster than the normal beta and delta chains; the beta X chain, however, did not separate from the normal beta chain in urea cellulose acetate electrophoresis. An instability test of the patient's hemolysate revealed the presence of an unstable component. Structural analysis of the abnormal beta chain indicated that the histidine residue at beta 92(F8) was replaced by an asparagine or aspartic acid residue. DNA amplified by polymerase chain reaction was sequenced by the dideoxy method. The nucleotide sequence of the beta 92 codon was AAC instead of CAC, suggesting that the amino acid substitution corresponded to His----Asn, which is the same as is found in Hb Redondo or beta 92(F8)His----Asn----Asp.

Amino Acid Sequence↗