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Biomedical subjects

W J Mellman

Publications and source records attributed to W J Mellman.

At least 19 recordsLinked to original sources
PubMed1983

Characterization of normal and abnormal variants of galactose-1-phosphate uridylyltransferase (EC 2.7.7.12) by isoelectric focusing.

Isoelectric focusing (IEF) in polyacrylamide gels has been used to study the isozymes of human galactose-1-phosphate uridylyltransferase (GALT) in erythrocytes and fibroblasts. In addition to the usefulness of IEF in differentiating normal, Duarte variant, and galactosemic homozygotes and heterozygotes, the ability of IEF to distinguish the residual GALT activity in two different galactosemic fibroblast lines and in revertants from them is demonstrated.

Cells, Cultured↗
PubMed1981

Reversion from deficiency of galactose-1-phosphate uridylytransferase (GALT) in an SV40-transformed human fibroblast line.

Control SV40-transformed human fibroblasts can be readily adapted to growth on medium containing galactose as sole hexose source (galactose-MEH). However, most cells from a line of SV40-transformed skin fibroblasts from a patient with galactosemia (galactose-1-phosphate uridylyltransferase (GALT) deficiency) died in galactose-MEM. Surviving cells of this line either grew in completely sugar-free media or had acquired significant amounts of GALT activity. Two presumptive revertant cell lines with GALT activity were characterized in detail. The expression of GALT in these two lines was stable in nonselective conditions. Each had different reaction maximum velocities with respect to uridine diphosphoglucose (UDPg) concentration as compared to residual activity in the parental cell strain or control cells. Both appeared to demonstrate heat-inactivation profiles for GALT than differed from the parental cells or controls. UDPG concentration was found to significantly alter the thermostability of GALT. A competitive radioimmunoassay for GALT showed that these two lines had amounts of the GALT protein comparable to that of the parental cell strain or control cells. The electrophoretic mobility of GALT from the two presumptive revertants was found to differ from control cells. It was concluded that structural gene changes were probably responsible for the apparent reversion in these lines.

Cell Line↗
PubMed1981

Successful cryopreservation of tissue and skin fibroblast cultures from patients with mucolipidosis II (I-cell disease).

Freeze-induced injury is a commonly observed phenomenon with cultured fibroblasts from patients with I-cell disease (ICD). Cells from these patients have therefore not been widely available to investigators, which has inhibited the study of this complex disorder. Skin biopsies from three ICD patients, as well as fibroblast cultures derived from these biopsies, have been subjected to a series of freezing experiments. The results show that when standard freezing protocols are employed, skin biopsies from these patients, in contrast to cultured fibroblasts, tolerate freezing well. In addition, when subjected to prolonged incubation in the confluent state, fibroblast cultures will consistently withstand frozen storage and, upon thawing, will yield actively growing cultures, biochemically and morphologically indistinguishable from the cultures that were frozen. There was a direct correlation between incubation time at confluence and subsequent cell survival after freezing.

Biopsy↗
PubMed1979

Deletion mapping: further evidence for the location of acid phosphatase (ACP1) within 2p23.

The human red cell acid phosphatase (ACP1) locus was assigned to region 2p23 leads to 2pter by Ferguson-Smith et al [3], more specifically to 2p23 by Hamerton et al [5]. We describe two unrelated patients with deletion of chromosome 2, with similar breakpoints in the distal portion of band p23 (del(2) (p23)). ACP1 typing in both patients revealed heterozygous BA phenotypes. Thus, we assign the locus for ACP1 to the distal portion of 2p23.

Abnormalities, Multiple↗
PubMed1979

Gene dosage effect: intraband mapping of human soluble glutamic oxaloacetic transaminase.

Quantitative assays of soluble GOT were performed on fibroblasts (from two individuals) with duplications of the long arm of chromosome 10 (10q24 leads to qter). Improved karyologic technique demonstrated that the duplications differ by half a band. Correlation of GOTS activity with the karyologic data indicates that the structural locus for GOTS maps within band 10q24. This study demonstrates the utility of this approach to fine structural mapping of the human genome.

Adult↗
PubMed1979

Assignment of a gene for uridine diphosphate galactose-4-epimerase to human chromosome 1 by somatic cell hybridization, with evidence for a regional assignment to 1pter yields 1p21.

The presence of human uridine diphosphate galactose-4-epimerase (GALE) was found to correlate with the presence of chromosome 1 in somatic cell hybrids between man and mouse. The gene for GALE can therefore be assigned to human chromosome 1. Using a chromosome 1 rearrangement, we have been able to regionally assign GALE to the pter yields p21 region.

Animals↗
PubMed1978

An evaluation of cytogenetic analysis as a primary tool in the assessment of recurrent pregnancy wastage.

Cytogenetic evaluation of couples with recurrent pregnancy wastage is frequently performed only after other possible etiologic factors have been excluded. Previous reports of studies using conventional and G-banding chromosome techniques in these couples have shown a higher frequency of translocations than that found in the general population. In the study reported here, both conventional and G-banded chromosome analyses were performed as a primary method of evaluation in 34 couples with recurrent fetal loss not ascertained by the birth of a child with a diagnosed chromosome disorder. Balanced translocations were found in 5 partners of the 34 couples studied. In only 2 of these cases was the translocation detected by conventional chromosome analysis. These results suggest that G-banded chromosome analysis should be a useful tool in the initial evaluation of couples with recurrent fetal wastage, rather than being recommended only after extensive investigation of other factors is unrewarding. The reproductive counseling of couples with a translocation detected on this basis is discussed.

Abortion, Habitual↗
PubMed1977

Mucopolysaccharidosis in a cat with arylsulfatase B deficiency: a model of Maroteaux-Lamy syndrome.

A Siamese cat that presented clinical signs similar to those seen in humans with mucopolysaccharidoses was studied. The animal excreted increased amounts of polymeric glycosaminoglycans in the urine, consisting almost entirely of dermatan sulfate. Electron microscopy of circulating polymorphonuclear leukocytes revealed the presence of many membrane-bound lamellar inclusion bodies. Sulfate incorporation studies with cultured skin fibroblasts indicated defective glycosaminoglycan degradation. These cells showed a deficiency in arylsulfatase B activity. The disorder appears similar or identical to the Maroteaux-Lamy syndrome described in humans.

Animals↗
PubMed1977

Assignment of the structural genes for the alpha subunit of hexosaminidase A, mannosephosphate isomerase, and pyruvate kinase to the region q22-qter of human chromosome 15.

Concordant segregation of the expression of the alpha subunit of human hexosaminidase A, human mannosephosphate isomerase, and pyruvate kinase was observed in somatic cell hybrids between either thymidine kinase-deficient mouse cells or thymidine kinase-deficient Chinese hamster cells and human white blood cells carrying a translocation of the distal half (q 22-qter) of the long arm of chromosome 15 to chromosome 17. A positive correlation was established between the expression of these human phenotypes and the presence of the distal half of the long arm of human chromosome 15.

Carbohydrate Epimerases↗