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Biomedical subjects

T Harano

Publications and source records attributed to T Harano.

At least 37 records · Page 2Linked to original sources

A diabetic case with hemoglobin J-Meerut and low HbA1C levels.

A diabetic patient with hemoglobin (Hb) J-Meerut and low HbA1C levels is reported. An automatic glycohemoglobin analyzer used for the determination of HbA1C revealed an abnormal peak of the peripheral blood obtained from a Japanese female with diabetes. She showed a lower HbA1C level (3.7%) than expected from her fasting plasma glucose (172 mg/dl). High performance liquid chromatography and isoelectric focusing indicated that her abnormal hemoglobin was Hb J-Meerut [alpha 120(H3)Ala-->Glu] and it accounted for 28.3% of the total hemoglobin. Abnormal hemoglobinemia should be considered when a major discrepancy between the levels of HbA1C and fasting plasma glucose is observed.

Blood Glucose↗

Japanese beta zero-thalassemia: molecular characterization of a novel insertion causing a stop codon.

During a physical checkup, a 42-year-old Japanese man with liver dysfunction was diagnosed as having beta-thalassemia. Using molecular biological techniques including PCR, we investigated the chemical basis of the hematological disorder. We found that a frameshift attributable to the insertion of a thymidine into or following the TTT sequence of codon 42 transformed codon 43 (GAG) into a stop codon (TGA). We believe that this mutation has not been previously reported.

Adult↗

The COL4A5 gene in Japanese Alport syndrome patients: spectrum of mutations of all exons. The Japanese Alport Network.

To determine the spectrum of mutations of the COL4A5 gene encoding type IV collagen among Japanese Alport syndrome (AS) patients, 60 unrelated patients (47 males and 13 females) from all over the country were recruited. Screening for mutations in all the exons (1 to 51) of the COL4A5 gene was carried out by PCR-SSCP analysis. A mobility shift was observed in 22 of 60 patients, and their genomic DNA were analyzed by the direct sequence method and using cloned ssDNA. Nine of these had missense mutations in the collagenous domain (in exons 39, 37, 31, 29, 28, 27, 21, 20, 19). Eight of these mutations were observed in a codon of glycine residue. Two were altered to arginine, two to valine, two to glutamic acid and two to aspartic acid. The other missense mutation was a change from isoleucine to serine in a interruption region. Five patients had small size base deletions and one had a 4 bp insertion resulting in frameshift (in exons 49, 41, 19, 14, 13). Three had a splice site mutation (in exons 49, 47, 27). One had a nonsense mutation (in exon 17). These mutations seemed to be pathogenic, but the phenotype, which includes extrarenal manifestations, can vary with respect to both expression and severity. The remaining mutations were three silent ones (in exons 19, 39, 46). In addition, major gene rearrangement seemed to be rare in Japanese AS patients.

Adult↗

A single-base mutation in exon 31 converting glycine 852 to arginine in the collagenous domain in an Alport syndrome patient.

In a family with Alport syndrome, molecular analysis of the COL4A5 gene, which encodes the alpha 5(IV) chain of glomerular basement membrane collagen, revealed a GGA-->AGA change in exon 31, resulting in substitution of an arginine for a glycine in position 852 of the polypeptide chain, between interruptions 16 and 17 of the triple-helical collagenous domain. The mutation causes the MaeI restriction sites, and could be easily diagnosed in the family members through restriction analysis. This one point mutation can be expected to interrupt type IV collagen molecules.

Adult↗

Hb Toranomon [beta 112(G14)Cys-->Trp]: a new unstable electrophoretically silent hemoglobin.

We describe a silent and unstable hemoglobin variant, Hb Toranomon, which was discovered by high performance liquid chromatography in an apparently healthy Japanese male during a Hb A1c assay. Isoelectrofocusing of his hemolysate and chromatographic separation of globin on a CM-cellulose column revealed no abnormality. The isopropanol precipitation test gave a positive result. Amino acid analysis of all peptides isolated from the tryptic digests of the aminoethylated and non-aminoethylated beta chain (beta A + beta X) by reversed phase high performance liquid chromatography indicated a substitution of Cys-->Trp at position 112 of the beta chain, which was confirmed by protein sequencing. cDNA sequencing showed the nucleotide sequence of the beta 112 codon to be TGG instead of TGT, confirming the amino acid substitution described above. The globin biosynthesis ratio (beta/alpha) was 1.00.

Adult↗

[Refractory anemia with excess of blasts (RAEB) with a high level of HbF that preceded apparent pancytopenia].

A 76-year-old male was kept under observation for idiopathic interstitial peumonitis in our hospital from August 1992. Laboratory data revealed a slightly high level of HbF (2.7%) but normal values of other hematological examination. The level of HbF increased slowly, and in April 1994, pancytopenia appeared for the first time. Bone marrow was normocellular with myelodysplasia and 9% blasts. Cytogenetic analysis revealed 46, XY, del (20) (q11;q13). He was diagnosed as having myelodysplastic syndrome (MDS), refractory anemia with excess of blasts. At diagnosis of MDS, the level of HbF was 20.0%. He developed acute myelocytic leukemia 3 months later. It has been reported that approximately 40% of patients with MDS have higher HbF levels than normal, which is considered to be functional abnormality of the MDS clone. It is suggested that the MDS clone had already increased in this patient at presentation, 32 months before pancytopenia appeared.

Aged↗

[The higher structure and physiological significance of hemoglobin].

The major function of hemoglobin, which is known as a highly advanced allosteric protein, is the transportation of oxygen and carbon dioxide between the lung and the tissues. Hemoglobin not only has the capability of binding a large quantity of oxygen but also the property of releasing oxygen in tissues where the pressure of oxygen is reduced with increase in the pressure of carbon dioxide. Thus, the blood can efficiently carry oxygen from the lung to the tissues. This physiological phenomenon is related strongly to the interaction between the higher structure of hemoglobin and various kinds of ions, e.g., H+, HCO3-, and 2,3-diphosphoglycerate.

Hemoglobins↗

Band 4.2 Komatsu: 523 GAT-->TAT (175 Asp-->Tyr) in exon 4 of the band 4.2 gene associated with total deficiency of band 4.2, hemolytic anemia with ovalostomatocytosis and marked disruption of the cytoskeletal network.

A novel mutation of 523 GAT-->TAT (175 Asp-->Tyr) in exon 4 of the band 4.2 gene was detected in a 37-year-old Japanese patient with total lack of band 4.2 protein, designated as allele 4.2 Komatsu. In this patient, moderate uncompensated hemolytic anemia (red cell count 3.38 x 10(6)/microliters, hemoglobin 10.8 g/dl, hematocrit 30.9%, reticulocytes 12.4%, indirect bilirubin 1.84 mg/dl) with ovalostomatocytosis and increased osmotic fragility had been noted since birth. Family studies revealed no overt hemolytic anemia in other family members, essentially normal red cell morphology, and a normal profile of red cell membrane proteins including band 4.2. Genetic studies proved that the proband was homozygous and all the family members studied were heterozygous with respect to the mutation of 523 GAT-->TAT of the band 4.2 gene. Although band 4.2 was completely absent in the proband, trace amounts of 72 kDa and 74 kDa peptides were detected in the red cells of all the family members, in which the mutation of 424 GCT-->ACT at exon 3 of the band 4.2 gene (Nippon type) was not present. Electron microscopic studies with the surface replica method and the quick-freeze deep-etching method showed the most marked disorganization of the cytoskeletal network in the patient's red cells in situ among the cases of band 4.2 deficiencies we have studied. This suggests that the amino acid of the band 4.2 protein, which was affected by the present mutation in exon 4, is much more crucial for the functioning of band 4.2 protein than that at codon 142 in exon 3. The cytoplasmic domain of band 3 in the proband's red cells was essentially normal in protein chemistry and in gene analysis with single-stranded conformation polymorphism (SSCP).

Adult↗

Hb Gunma (beta Gunma) with pulmonary embolism.

A 67-year-old woman with pulmonary embolism was suspected to have beta-thalassemia based on microcytosis, hemolysis and a negative red cell stability test. The DNA sequencing analysis of beta-globin gene, however, revealed the deletion of three nucleotides within codon 127-128, leading to substitution of glutamine and alanine residues at 127 and 128 by proline, namely Hb Gunma. This mutant is characterized by the fact that no abnormal hemoglobin is detected in the circulating blood, and is classified as a thalassemic hemoglobinopathy. The present case showed a relatively hemolytic manifestation.

Aged↗

[An abnormal hemoglobin which was found by chance at a health checkup].

A 68-year-old female visited our hospital because of low hemoglobin A1c content, which was found by chance at a health checkup. She did not have any symptom or sign except hypertension and low HbA1c. To determine the reason why HbA1c was so low in usual laboratory test, we carried out isoelectrofocusing (IEF) of the hemolysate, Hb instability test, and detection and isolation of the abnormal globin chain by urea CM-cellulose column chromatography. The abnormal beta-globin chain was digested with TPCK-trypsin, and the tryptic peptides were separated by HPLC on a reversed phase column. Finally the determination of amino acid composition and amino acid sequence of the abnormal peptide were performed. The Hb variant was identified as Hb Riyadh (beta 120Lys-->Asn). The detection and analysis of abnormal hemoglobin will be expected to increase in accordance with the increased opportunity of public health checkup.

Aged↗