Ryuji Kawaguchi

Establishment of a myeloid leukaemic cell line (SKNO-1) from a patient with t(8;21) who acquired monosomy 17 during disease progression

A novel cell line SKNO‐1 was established from the bone marrow cells of a 22‐year‐old male suffering from acute myeloblastic leukaemia (AML) M2 with t(8;21) whose disease became resistant to chemotherapy after acquisition of 17 monosomy. SKNO‐1 has been maintained for more than 36 months as a granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) dependent line.

POINT MUTATIONS OF RHODOPSIN GENE FOUND IN JAPANESE FAMILIES WITH AUTOSOMAL DOMINANT RETINITIS PIGMENTOSA (ADRP)

SummaryThe mutations of codon 17, 23, 58, and 347 of rhodopsin gene were investigated in 24 unrelated Japanese families including 33 patients with autosomal dominant retinitis pigmentosa (ADRP). A patient with codon 17 mutation (Thr-17-Met, ACG→ATG) and a family including 4 patients with codon 347 mutation (Pro-347-Leu, CCG→CTG) were detected among them. Their clinical findings were extremely different between the two mutations. The former showed type 2 and the latter showed type 1 ADRP. No mutation of codon 23 and 58 was detected in any families so far analyzed in the present study. Clinical findings associated with the mutation in codon 17 and 347 of the rhodopsin gene show an existence of allelic heterogeneity.

Establishment of a leukaemic cell line from a patient with acquisition of chromosomal abnormalities during disease progression in myelodysplastic syndrome

Summary. A cell line designated SKM‐1 was newly established from leukaemic cells of a 76‐year‐old Japanese male patient with monoblastic leukaemia following myelodysplastic syndrome (MDS). The cells were obtained from peripheral blood of the patient when he lost multiple point mutations of ras genes with acquisition of chromosomal abnormalities during disease progression in MDS. The cells grew as a single floating cell, and have been continuously growing with the morphological characteristics of immature monoblasts by serial passages during the past 42 months with a doubling time of about 48 h. By cytochemical analysis. the cloned cells were positive for butyrate esterase, but negative for the Epstein‐Barr virus associated nuclear antigen. Phenotypic analysis revealed the expression of myelomonocyte specific antigens such as CD4, CD13, CD33 and HLA‐DR. Cells from the primary peripheral blood and those from SO passages of the SKM‐1 cell line both possessed no activated ras genes but showed karyotype abnormalities with 46.XY, del(9)(q13;q22), der(17) t(17:?)(p13:?). The SKM‐1 cells have two mutations in p53 gene and overexpress the pS3 products. This cell line may contribute to a better understanding of molecular mechanisms in the progression from MDS to myelogenous leukaemia.

Analysis of the genotypes for aldehyde dehydrogenase 2 in Japanese patients with primary gout.

Alcoholic ingestion is one of the major factors for increasing serum uric acid levels. Genotypes of aldehyde dehydrogenase 2 (ALDH2, E.C.1.2.1.3), which regulates the sensitivity of an individual to ethanol, were determined in Japanese patients with gout and control subjects by allele specific oligonucleotide hybridization using PCR amplified gene. The most common allele ALDH2*1 codes for normal ALDH2 activity, while the less common allele ALDH2*2 codes for a lower enzyme activity. The frequency of homozygotes of ALDH2*2 was significantly lower in patients with gout than those with rheumatoid arthritis or a normal population. Plasma and urinary hypoxanthine levels were strikingly increased after ethanol drinking in homozygotes for ALDH2*1 but not in heterozygotes for ALDH2*1/ALDH2*2, indicated extensive purine nucleotide degradation in homozygote for ALDH2*1. These data indicated that alcohol ingestion may not be the requisite factor but is deeply involved in the pathogenesis of gout and hyperuricemia.

A germline mutation abolishing the original stop codon of the human adenine phosphoribosyltransferase (APRT) gene leads to complete loss of the enzyme protein

Abstract Adenine phosphoribosyltransferase (APRT) is a purine metabolic enzyme and a homozygous deficiency in this enzyme causes 2,8-dihydroxyadenine urolithiasis. Various germline abnormalities have been described, but we report here a unique type of germline mutation in a homozygous individual (SY) who had excreted 2,8-dihydroxyadenine crystals. In SY, TCA was substituted for the physiological stop codon TGA. This base substitution generates a new HinfI restriction site, and, using the polymerase chain reaction and subsequent digestion by this enzyme, it was confirmed that SY is homozygous for the base substitution. This base change is unique in that it generates an open reading frame that extends to the poly(A) addition site. The amount of mRNA in transformed B cells from SY was approximately a quarter of that in control subjects and no APRT proteins were detected. In eukaryotes, unlike in prokaryotes, no rescue systems for defective polypeptide termination caused by a missing stop codon have been found. Therefore, the outcome of the defect of SY is unclear from present knowledge about termination of polypeptide synthesis. Investigations into the mechanisms of the absence of protein in the cells of SY may lead to a better understanding of the physiological and nonphysiological termination of polypeptide synthesis in eukaryotic cells.

A non-radioactive method for the detection of a common mutant allele of aldehyde dehydrogenase 2.

About 50% of Japanese have been estimated to possess at least one ALDH2*2 allele with a substitution of AAA for GAA at codon 487 of the aldehyde dehydrogenase gene. This mutation is tightly associated with the sensitivity of an individual to alcohol. We developed a method of identifying the ALDH2*2 allele by a non-radioactive technique. DNA from individuals was subjected to polymerase chain reaction in which part of the aldehyde dehydrogenase 2 gene was amplified. After dot-blotting onto nylon membranes, the DNA was hybridized with biotin-labelled allele-specific oligonucleotides. Determination of genotypes on 77 unrelated healthy Japanese individuals, using the conventional method and our new method with gradient hybridization temperature and competitive oligonucleotides, indicated that the latter was superior to the former.

Analysis of Herpes Virus Group (DNA) from Cerebrospinal Fluid in Vogt-Koyanagi-Harada Disease

In order to detect herpes virus group DNA including that of the Epstein-Barr virus (EBV) in patients with Vogt-Koyanagi-Harada disease (VKH), the authors employed the polymerase chain reaction (PCR) procedure using DNA from cerebrospinal fluid (CSF) obtained from patients with VKH. Method. Seven CSF samples were obtained from six definite, active VKH cases and DNA was isolated. DNA fragments containing parts of herpes simplex virus (HSV), herpes zoster virus (VZV), cytomegalo virus (CMV), EBV and human herpes virus type 6 (HHV-6) sequences were amplified by PCR. Results. No DNA fragment corresponding to the DNA sequence of the herpes virus group was detected. Conclusion. Our results suggest that the herpes virus group does not have a close association with the cause of VKH.

Simultaneous detection of multiple mutations conferring streptomycin resistance inMycobacterium tuberculosis using nanoscale engineered biomagnetites

Streptomycin-resistantMycobacterium tuberculosis has been attributed to two distinct classes of mutations, including point mutations within therpsL gene (three mutation sites) and therrs gene (seven mutation sites). We have developed an automated simultaneous detection system of multiple mutations based on thermal dissociation curve analysis for streptomycin resistance inM. tuberculosis using streptavidin-labeled bacterial magnetic particles (SA-BacMPs). With consideration for time and cost effectiveness, we used fewer PCR reactions, with a long PCR target (rpsL, 182 bp;rrs, 467 bp) including multiple mutation sites. In order to improve the amount of target DNA captured on BacMPs through streptavidin-biotin binding, several reaction conditions, such as salt species and concentration in the buffer, and reaction temperature were examined. Compared to the commonly used 1M NaCl solution, the amount of DNA captured on SA-BacMPs was about six times greater (approx 5 pmoles/50 μg BacMPs) in the 2M LiCl solution. Under these conditions, automated nucleotide discriminations of 10 targets inrpsL andrrs genes of streptomycin-resistant and wild-type strains were successfully performed at the same time.

Study on an improved isolation method of human α1-antichymotrypsin and the measurement using radioimmunoassay in various human body fluids

α1-antichymotrypsin (α1AC) is known to specifically inhibit the activity of chymotrypsin-like proteases, and considered to be one of the acute phase reactants. In our previous study, the α1AC level was increased in gastric juice from the patients with gastric cancer, when compared to those in benign gastrointestinal disorders or normal controls, α1AC was purified from serum using the method of salting out and gel chromatography which was modified from the method of Travis, et al. The moleculer weight of the purified α1AC was 58, 000 daltons by SDS-polyacrylamide gel electrophoresis, which was completely identical to the report by Lame and Hayem. The new highly specific and sensitive radioimmunoassay (RIA) was established for α1AC. The RIA was prepared using the purified α1AC and anti-α1AC antibody commarcially available. The α1AC level was first determined in some human body fluids, such as gastric juice, bile, ascitic, pleural, cerebrospinal and synovial fluids.