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Biomedical subjects

S Tomatsu

Publications and source records attributed to S Tomatsu.

102 records · Page 6Linked to original sources
PubMed1989

Heterogeneity of the gamma-globin gene sequences in Japanese individuals: implication of gene conversion in generation of polymorphisms.

The linked fetal globin genes (the G gamma- and A gamma-globin genes) were cloned from Japanese individuals with three different haplotypes of the HindIII polymorphisms within the gamma-globin genes. Determination of nucleotide sequences of the segment spanning from IVS2 to the 3' flanking region of each gamma-globin gene revealed that nucleotide differences are located at 43 positions and a stretch of simple GT or GC sequences. Almost half of the nucleotide changes could be accounted for by gene conversion between the G gamma- and A gamma-globin genes. We found that gene conversion had created the SacI polymorphic site just downstream of the A gamma-globin coding region. Association of the SacI polymorphic site with the HindIII polymorphic site suggests that the region containing these two sites was derived from that of the linked G gamma-globin gene through a gene conversion event. The nucleotide sequences obtained here are identical to those of the Caucasoid fetal globin genes of the same haplotypes, with the exception of some sequence changes in the hot spots of mutations. These results indicate that the sequence heterogeneity of the gamma-globin genes can be classified into three major categories according to HindIII haplotypes. The possible mechanisms of generation of the heterogeneity of the gamma-globin gene sequences are discussed.

Base Sequence↗
PubMed1987

The response to medical litholytic treatment of gallstones according to their specific gravity.

The buoyancy of gallstones was observed by taking anterior-posterior scout X-ray films of two patients standing during endoscopic retrograde cholangiography. In case 1, the large and small gallstones differed in buoyancy, and ursodeoxycholic acid treatment dissolved the floating small stones while failing to dissolve the nonfloating large stone. In case 2, both the large and small stones floated and are being dissolved by ursodeoxycholic acid treatment. Since floating or nonfloating and the plane of flotation depend on the specific gravity of the gallstone, the above findings suggest that a gallstone with a low specific gravity is more readily dissolved than one with a high specific gravity. The present method of estimating the buoyancy of gallstones was therefore considered extremely useful in selecting patients for medical litholytic treatment.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1983

[Carcinoembryonic antigen (CEA), serum amylase and pancreozymin-secretin test in relation to stages of pancreatic cancer].

In cases of surgically proved pancreatic carcinoma, preoperative values of serum CEA, serum amylase and pancreozymin-secretin test (PST) were seen if they related to the macroscopic stages of the tumor determined by "General Rules for Surgical and Pathological Studies on Cancer of Pancreas" offered by Japanese Pancreatic Society in April 1982. Serum CEA was determined in 43 cases, serum amylase in 34 cases and PST was done in 28 cases. All of CEA, amylase and PST showed no statistically significant relationship to the stages of the carcinoma. This may suggest that these tests may not be a useful indicator of the stage of tumor.

Amylases↗
PubMedDate not supplied

Prenatal diagnosis of peroxisomal disorders. Biochemical and immunocytochemical studies on peroxisomes in human amniocytes.

Prenatal diagnoses of peroxisomal disorders, including peroxisome-deficient Zellweger syndrome, isolated deficiency of peroxisomal beta-oxidation enzyme and rhizomelic type chondrodysplasia punctata were investigated by means of the lignoceric acid oxidation assay, indirect immunofluorescence staining and pulse-chase experiments, using cultured amniocytes. Assessment of peroxisomal beta-oxidation activity by means of [1-14C]lignoceric acid oxidation is essential for the diagnosis of a single enzyme deficiency of peroxisomal beta-oxidation with detectable enzyme protein. For the diagnosis of Zellweger syndrome, the absence of peroxisomes was readily determined by immunofluorescence staining of only a few amniocytes. Evidence for abnormal processing of 3-ketoacyl-CoA thiolase leads to the diagnosis of rhizomelic chondrodysplasia punctata. All the fetuses were considered to be normal and the neonates were normal. Use of these methods requires only a small number of amniocytes and will facilitate the prenatal diagnosis of peroxisomal disorders.

Acetyl-CoA C-Acyltransferase↗
PubMedDate not supplied

Suppression of IgA production by lymphocytes induced by diphenylhydantoin.

In this study, the mechanisms for suppression of immunoglobulin production by lymphocytes induced by diphenylhydantoin (DPH) were investigated using peripheral blood mononuclear cells from one patient 3 months after discontinuation of DPH, when IgA deficiency was improved. Immunoglobulin production in PBMCs was dose-dependently suppressed by DPH and the suppressive effect of DPH on IgA production tended to be greater than the effect on IgM or IgG production. Moreover, cell separation experiments indicated that DPH suppresses immunoglobulin production by PBMCs through a suppression of B cell, but not T cell, function. The finding that the suppressive effect of DPH on IgA production tended to be greater than the effect on IgM or IgG production might be related to the fact that the alpha-chain gene is located in the 3' end of the gene coding the constant regions of human heavy chains.

B-Lymphocytes↗
PubMedDate not supplied

Effects of the antiallergic drug azelastine hydrochloride on proliferative responses of lymphocytes to food antigens in patients with food-sensitive atopic dermatitis.

We previously reported that the proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin (OA) or bovine serum albumin (BSA) in children with atopic dermatitis (AD) who are sensitive to hen's egg or cow's milk were significantly higher than those of healthy children and hen's egg- or cow's milk-sensitive children with immediate symptoms. Azelastine hydrochloride is an antiallergic drug used in the treatment of rhinitis and asthma. In this study, we have shown that the proliferative responses of PBMCs to OA are concentration-dependently inhibited by azelastine in patients with AD. Moreover, the inhibition resulted from the effects of azelastine on T-cells.

Animals↗