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K H Astrin

Publications and source records attributed to K H Astrin.

At least 37 records · Page 2Linked to original sources
PubMed1991

Regional assignment of the human uroporphyrinogen III synthase (UROS) gene to chromosome 10q25.2----q26.3.

Uroporphyrinogen III synthase [UROS; hydroxymethylbilane hydro-lyase (cyclizing), EC 4.2.1.75] is the fourth enzyme in the human heme biosynthetic pathway. The recent isolation of the cDNA encoding human UROS facilitated its chromosomal localization. Human UROS sequences were specifically amplified by the polymerase chain reaction (PCR) from genomic DNA of two independent panels of human-rodent somatic cell hybrids. There was 100% concordance for the presence of the human UROS PCR product and human chromosome 10. For each of the other chromosomes, there was 19%-53% discordance with human UROS. The chromosomal assignment was confirmed by Southern hybridization analysis of DNA from somatic cell hybrids with the full-length UROS cDNA. Using human-rodent hybrids containing different portions of human chromosome 10, we assigned the UROS gene to the region 10q25.2----q26.3.

Animals↗
PubMed1990

Human delta-aminolevulinate synthase: assignment of the housekeeping gene to 3p21 and the erythroid-specific gene to the X chromosome.

delta-Aminolevulinate synthase (ALAS) catalyzes the first committed step of heme biosynthesis. Previous studies suggested that there were erythroid and nonerythroid ALAS isozymes. We have isolated cDNAs encoding the ubiquitously expressed housekeeping ALAS isozyme and a related, but distinct, erythroid-specific isozyme. Using these different cDNAs, the human ALAS housekeeping gene (ALAS1) and the human erythroid-specific (ALAS2) gene have been localized to chromosomes 3p21 and X, respectively, by somatic cell hybrid and in situ hybridization techniques. The ALAS1 gene was concordant with chromosome 3 in all 26 human fibroblast/murine(RAG) somatic cell hybrid clones analyzed and was discordant with all other chromosomes in at least 6 of 26 clones. The regional localization of ALAS1 to 3p21 was accomplished by in situ hybridization using the 125I-labeled human ALAS1 cDNA. Of the 43 grains observed over chromosome 3, 63% were localized to the region 3p21. The gene encoding ALAS2 was assigned by examination of a DNA panel of 30 somatic cell hybrid lines hybridized with the ALAS2 cDNA. The ALAS2 gene segregated with the human X chromosome in all 30 hybrid cell lines analyzed and was discordant with all other chromosomes in at least 8 of the 30 hybrids. These results confirm the existence of two independent, but related, genes encoding human ALAS. Furthermore, the mapping of the ALAS2 gene to the X chromosome and the observed reduction in ALAS activity in X-linked sideroblastic anemia suggest that this disorder may be due to a mutation in the erythroid-specific gene.

5-Aminolevulinate Synthetase↗
PubMed1989

Fabry disease: six gene rearrangements and an exonic point mutation in the alpha-galactosidase gene.

Fabry disease, an X-linked recessive disorder of glycosphingolipid catabolism, results from the deficient activity of the lysosomal hydrolase, alpha-galactosidase. Southern hybridization analysis of the alpha-galactosidase gene in affected hemizygous males from 130 unrelated families with Fabry disease revealed six with different gene rearrangements and one with an exonic point mutation resulting in the obliteration of an Msp I restriction site. Five partial gene deletions were detected ranging in size from 0.4 to greater than 5.5 kb. Four of these deletions had breakpoints in intron 2, a region in the gene containing multiple Alu repeat sequences. A sixth genomic rearrangement was identified in which a region of about 8 kb, containing exons 2 through 6, was duplicated by a homologous, but unequal crossover event. The Msp I site obliteration, which mapped to exon 7, was detected in an affected hemizygote who had residual enzyme activity. Genomic amplification by the polymerase chain reaction and sequencing revealed that the obliteration resulted from a C to T transition at nucleotide 1066 in the coding sequence. This point mutation, the first identified in Fabry disease, resulted in an arginine356 to tryptophan356 substitution which altered the enzyme's kinetic and stability properties. The detection of these abnormalities provided for the precise identification of Fabry heterozygotes, thereby permitting molecular pedigree analysis in these families which revealed paternity exclusions and the first documented new mutations in this disease.

Blotting, Southern↗
PubMed1989

Fabry disease: molecular genetics of the inherited nephropathy.

Originally described as a dermatologic curiosity by Fabry in 1898 and independently by Anderson in the same year, Fabry disease is now recognized as an inborn error of glycosphingolipid metabolism resulting from the defective activity of the lysosomal enzyme, alpha-galactosidase A (see Desnick and Sweeley for a comprehensive review). The enzymatic defect, transmitted by an X-linked recessive gene, leads to the accumulation of neutral glycosphingolipids with terminal alpha-galactosyl residues in the plasma and in the lysosomes of endothelial, perithelial, and smooth muscle cells of the cardiovascular-renal system and, to a lesser extent, in reticuloendothelial, myocardial, and connective tissue cells. Epithelial cells in the kidney, cornea, and other tissues contain the lysosomal depositions, as do the ganglia and perineural cells of the autonomic nervous system. The major accumulated substrate is globotriaosylceramide [galactosyl-(alpha 1----4)-galactosyl-(beta 1----4)-glucosyl-(beta 1----1')-ceramide]; another substrate, galabiosylceramide [galactosyl-(alpha 1----4)-galactosyl-(beta 1----1')-ceramide] is deposited primarily in renal lysosomes. The clinical manifestations of Fabry disease are the sequelae of the anatomical and physiologic alterations produced by progressive glycosphingolipid deposition. Clinical onset of the disease in hemizygous males usually occurs during childhood or adolescence, with periodic crises of severe pain in the extremities (acroparesthesias), the appearance of the vascular cutaneous lesions (angiokeratoma), hypohidrosis, and the characteristic corneal dystrophy. With increasing age, the major morbid symptoms of the disease result from the progressive infiltration of glycosphingolipid in the cardiovascular-renal system. Death usually occurs from renal, cardiac, or cerebral complications of the vascular disease. Prior to the availability of treatment by renal transplantation or dialysis, the average age at death for affected males was about 40 years. Heterozygous females, who may exhibit the disease in an attenuated form, are most likely to have only corneal opacities. Previously, the diagnosis of affected hemizygous males and heterozygous females was based on clinical findings and the levels of alpha-galactosidase A activity in easily obtained sources, e.g., plasma and isolated lymphocytes or granulocytes. Because the gene encoding alpha-galactosidase A undergoes random X-inactivation, the expressed level of enzymatic activity in females heterozygous for the disease gene may vary significantly, thereby making accurate carrier detection difficult.(ABSTRACT TRUNCATED AT 400 WORDS)

Fabry Disease↗
PubMed1987

Cholesteryl ester storage disease: pathologic changes in an affected fetus.

The prenatal diagnosis of cholesteryl ester storage disease, a rare autosomal recessive disorder, was made by demonstration of deficient lysosomal acid lipase activity in cultured amniocytes from an at-risk fetus. The histochemical and ultrastructural changes in the affected fetus (at 17 gestational weeks) are described and compared to findings in liver and duodenal biopsy specimens from a 9-year-old homozygous female. Massive lysosomal cholesterol and lipid accumulation was demonstrated in fetal hepatocytes, adrenal cells and syncytiotrophoblasts. Of particular note was the observation of extensive necrosis in the fetal adrenal glands. Necrosis of the adrenals may precede the calcification observed in some patients with cholesteryl ester storage disease and in most patients with Wolman disease, an allelic variant due to lysosomal acid lipase deficiency. Fibrosis of the liver and lipid accumulation in macrophages in liver and duodenum, which were present in the 9-year-old homozygote, were not observed in the affected fetus, and therefore, may represent later manifestations of the disease.

Child↗
PubMed1987

Human delta-aminolevulinate dehydratase: chromosomal localization to 9q34 by in situ hybridization.

The structural gene for human delta-aminolevulinate dehydratase (ALA-D) has been localized to chromosomal region 9q34 by in situ hybridization using a [125I]-labeled human delta-aminolevulinate dehydratase cDNA. Of the 150 silver grains analyzed, 25% were localized to chromosome 9q, while 12% and 8% were on chromosomes 1p and 13q, respectively. The single chromosomal region q34 had over 90% of the total grains observed on chromosome 9. In contrast, the grains on chromosomes 1p and 13q were dispersed, consistent with the absence of any human ALA-D pseudogenes. Southern blot analysis of somatic cell hybrids informative for ALA-D (Wang et al. 1985) also was consistent and supported the finding of only one locus for this heme biosynthetic enzyme.

Chromosome Banding↗
PubMed1987

delta-Aminolevulinic acid dehydratase isozymes and lead toxicity.

ALAD is a zinc metalloenzyme whose inhibition by lead is the first and most sensitive indicator of lead exposure and whose decreased activity has been implicated in the pathogenesis of lead poisoning. This heme biosynthetic enzyme is encoded by a gene located at chromosome 9q34, which has two codominant alleles, ALAD1 and ALAD2. The occurrence of two frequent alleles for ALAD stimulated an investigation into the possible pharmacogenetic role of the enzyme polymorphism in lead poisoning. In a New York City population at high risk for lead exposure, individuals heterozygous or homozygous for the less common allele, ALAD2, had blood lead levels greater than or equal to 30 micrograms/dl more frequently than expected. These findings suggest a potential genetic susceptibility to lead poisoning in individuals with the ALAD 1-2 and 2-2 phenotypes.

Alleles↗
PubMed1987

Fabry disease: molecular diagnosis of hemizygotes and heterozygotes.

Fabry disease, an X-linked inborn error of glycosphingolipid catabolism, results from the deficient activity of the lysosomal hydrolase, alpha-galactosidase A. Previously, the diagnosis of affected hemizygous males and heterozygous females was based on clinical findings and the levels of alpha-galactosidase A activity in easily obtained sources such as plasma and isolated lymphocytes or granulocytes. Since the gene encoding alpha-galactosidase A undergoes random X-inactivation, the expressed level of enzymatic activity in females heterozygous for the disease gene may vary significantly, thereby making accurate carrier detection difficult. The recent cloning and characterization of the full-length cDNA encoding human alpha-galactosidase A now permits the accurate diagnosis of affected hemizygotes and heterozygous females. In families with gene rearrangements or an altered restriction endonuclease cleavage site, precise diagnosis can be accomplished by Southern hybridization analysis using the alpha-galactosidase A cDNA as probe. In families with normal restriction patterns, two restriction fragment length polymorphisms have been identified in and adjacent to the alpha-galactosidase A gene which also allow precise hemizygote and heterozygote diagnosis. In addition, the recent identification of polymorphic, random DNA sequences (DXS17 and DXS87) located near the alpha-galactosidase A locus permits molecular diagnosis in informative families. Further evaluation of DXS17, DXS87 and other closely linked random DNA probes is required in order to determine their informativeness, proximity to the alpha-galactosidase A locus and, hence, accuracy for molecular diagnosis.

Alleles↗
PubMed1985

delta-Aminolevulinate dehydratase: induced expression and regional assignment of the human gene to chromosome 9q13----qter.

The structural gene encoding human delta-aminolevulinate dehydratase has been assigned to the long arm of chromosome 9 by somatic cell hybridization techniques using murine erythroleukemia-human fibroblast somatic cell hybrids. Dimethyl sulfoxide induction of erythroid differentiation in these hybrid cells resulted in a 3 to 12-fold increase in the levels of total delta-aminolevulinate dehydratase. Human delta-aminolevulinate dehydratase was detected by an immunodiscrimination assay using polyclonal mouse anti-human delta-aminolevulinate dehydratase antibodies. Of four primary hybrid clones, each from an independent fusion, one hybrid line, XX-8, was positive for human delta-aminolevulinate dehydratase. Examination of 23 secondary, tertiary, and quaternary XX-8 subclones revealed that the expression of the human isozyme segregated with human chromosome 9q, confirming the provisional regional assignment made by classical linkage studies. One positive quaternary clone, XX-8-H21-H7-2, expressed human delta-aminolevulinate dehydratase activity and contained only human 9q13----qter. In addition, studies of tertiary and quaternary subclones from two series, XX-8-A31 and XX-8-H21-H7, indicated that murine regulatory factors increased the human as well as the murine enzymatic activity following induction of erythroid differentiation.

Animals↗
PubMed1984

Regional assignment of the structural gene for human alpha-L-iduronidase.

The structural gene encoding human alpha-L-iduronidase has been assigned to chromosome 22 by using immunologic, electrophoretic, and somatic cell hybridization techniques. Polyclonal rabbit antibodies raised against purified human low-uptake alpha-L-iduronidase were used to discriminate the human and murine isozymes by a sensitive immuno-precipitation assay. The human chromosome constitution of each clone was determined by cytogenetic and enzyme marker electrophoretic techniques. In 65 human (fibroblast)-mouse (RAG) somatic cell hybrids (from four independent fusions), the expression of human alpha-L-iduronidase was 100% concordant with the presence of human chromosome 22; the assignment was confirmed by the demonstration of the human enzyme in tertiary somatic cell hybrids containing only chromosome 22. Further verification of the gene assignment was made by detection of the human enzyme in tertiary chromosome 22 positive hybrids by Ouchterlony immunodiffusion and rocket immunoelectrophoretic experiments with polyclonal anti-human alpha-L-iduronidase antibodies that were monospecific for the human enzyme. Expression of human enzymatic activity in chromosome 22 positive hybrid lines was markedly reduced; for example, a tertiary hybrid (R-G21-J-15), which contained an average of 1.7 chromosome 22s per cell, only had about 15% of the activity detected in normal diploid fibroblasts. Immunologic studies suggested that the reduced expression was due to abnormal post-translational processing or aggregation (or both) of the human and murine isozymes in these hybrids. Regional assignment of the human structural gene to 22pter----q11 was accomplished by gene dosage studies using diploid human fibroblast lines that were partially monosomic or trisomic for chromosome 22.

Animals↗
PubMed1984

Assignment of the structural gene encoding human aspartylglucosaminidase to the long arm of chromosome 4 (4q21----4qter).

The structural gene for the human lysosomal enzyme aspartylglucosaminidase (AGA) has been assigned to chromosome 4 using somatic cell hybridization techniques. The human monomeric enzyme was detected in Chinese hamster-human cell hybrids by a thermal denaturation assay that selectively inactivated the Chinese hamster isozyme, while the thermostable human enzyme retained activity. Twenty informative hybrid clones, derived from seven independent fusions, were analyzed for the presence of human AGA activity and their human chromosomal constitutions. Without exception, the presence of human AGA in these hybrids was correlated with the presence of human chromosome 4. All other human chromosomes were excluded by discordant segregation of the human enzyme and other chromosomes. Two hybrid clones, with interspecific Chinese hamster-human chromosome translocations involving the long arm of human chromosome 4, permitted the assignment of human AGA to the region 4q21----4qter.

Amidohydrolases↗
PubMed1982

Assignment of human alpha 1-antitrypsin to chromosome 14 by somatic cell hybrid analysis.

Human alpha 1-antitrypsin ( alpha-1-AT;Pi) production was analyzed in 11 primary mouse hepatoma-human lymphoid cell hybrids and in 14 secondary rat hepatoma-human fetal liver fibroblast hybrids. The presence of human alpha-1-AT was determined by Laurell immunoelectrophoresis of concentrated and isotopically labeled supernatant medium. Human alpha-1-AT production segregated in the mouse-human hybrids concordantly with human purine nucleoside phosphorylase and with chromosome 14. All rat-human hybrids that were alpha-1-AT positive were also positive for human purine nucleoside phosphorylase and chromosome 14. Our study demonstrated the usefulness of rodent hepatoma cell hybrids for mapping human liver-specific genes because differentiated functions are expressed despite the fact that the human parental cells did not express these functions. Our study also showed that human alpha-1-AT gene product can be processed for secretion in the rodent hepatoma cellular environment. The mouse-human hybrids showed that no other human chromosome carries genes necessary for processing or secretion of human alpha-1-AT in the hybrid cell milieu.

Animals↗
PubMed1982

Assignment of the gene for cytosolic alanine aminotransferase (AAT1) to human chromosome 8.

The segregation of human cytosolic alanine aminotransferase (AAT1) and the individual human chromosomes has been studied in 27 secondary and tertiary rat hepatoma-human (liver) fibroblast hybrids. The staining solution used to visualize AAT activity on starch gels was specific for AAT since it was visualized only when all components of the stain were present. The locus for human AAT1 has been assigned to chromosome 8.

Alanine Transaminase↗
PubMed1977

Forward and reverse mutations affecting the kinetics and apparent molecular weight of mammalian HGPRT.

Chinese hamster cells selected for resistance to 8-azaguanine following mutagenesis have hypoxanthine-guanine phosphoribosyltransferase (HGPRT; E.C. 2.4.2.8) with characteristics compatible with different mutations in the structural gene for that enzyme. Using immunopurification and SDS-polyacrylamide electrophoresis, mutants producing antigenically active forms of the enzyme can be analyzed for changes in the molecular weight of HGPRT. Enzyme subunits from mutants RJK3 and RJK39 are reduced in molecular weight by an estimated 4 and 2%, respectively. HGPRT activity is not detectable in RJK39. The enzyme from RJK3 is active but has altered substrate binding properties. Enzymes from two other mutants with altered kinetic properties, RJK44 and RJK47, have normal molecular weights. The genetic alterations of RJK44 and 47 are probably missense mutations, while RJK3 and 39 might contain either deletions or mutations causing premature peptide chain termination. Somatic cell hybridization between RJK39 and a revertant of that strain with HGPRT of normal molecular weight revealed that the revertant probably arose by intragenic mutation rather than extragenic mutation or suppression.

Aminopterin↗
PubMed1970

Lesch-Nyhan syndrome: preventive control by prenatal diagnosis.

The Lesch-Nyhan syndrome was detected in a fetus at a time sufficiently early to allow termination of the pregnancy. The feasibility of a preventive program for control of a severe sex-linked neurological disease through prenatal diagnosis is thus demonstrated.

Adenine↗
PubMed1967

Light chains of rabbit immunoglobulin: assignment to the kappa class.

Normal rabbit gamma globulin was reduced under conditions presumed to break only interchain disulfide bridges, and the reduiced product was then blocked with C(14)-iodoacetamide. The light chains were separated from the heavy chains and subjected to peptic digestion. Two radioactive peptides were recovered from the digest. The peptides are apparently overlapping and represent the carboxyterminuis. Comparison of this region in the rabbit light chains with the corresponding amino acid sequences in various mouse and human light chains indicates that the rabbit light chains are of the (K)-class.

Amino Acid Sequence↗