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Biomedical subjects

S M Hanash

Publications and source records attributed to S M Hanash.

At least 109 records · Page 6Linked to original sources
PubMed1985

Analysis of neuroblastoma cell proteins using two-dimensional electrophoresis.

Polypeptide patterns of nine neuroblastoma and thirteen other cell lines were analyzed by 2-D PAGE. Of 600 polypeptide spots scored one was present in all neuroblastoma cell lines and none of the other cell types analyzed. Three were markedly increased in intensity in neuroblastoma relative to other cell lines, and one was markedly decreased in neuroblastoma and melanoma. These data provide a basis for a more detailed analysis of the polypeptide pattern of neuroblastoma cells.

Cells, Cultured↗
PubMed1984

Band 4.1-like proteins of the bovine lens. Effects of differentiation, distribution and extraction characteristics.

Bovine lens epithelium, cortex and nucleus were screened for the presence of red-cell-membrane band 4.1-like proteins by using an immunoblot method. Lens epithelial cells were found to contain proteins of Mr 78 000 and higher (approximately 150 000) that cross-reacted with anti-(protein 4.1) sera. Fibre cells of the superficial cortex were also found to contain these two proteins, as well as an additional protein of approx. 80 000 Mr. In contrast, deep layers of the cortex and the lens nucleus contained no detectable cross-reactive protein at these Mr values. Treatment of a crude membrane fraction prepared from superficial bovine cortices with a low-ionic-strength buffer resulted in release of the high-Mr band 4.1-like protein. The 80 000- and 78 000-Mr proteins remained with the membrane fraction in low-ionic-strength buffer, but were released into solution by high-ionic-strength-buffer treatment. We have also demonstrated that the human red-blood-cell membrane, like lens epithelial cells and fibre cells, also contains a high-Mr band 4.1-like protein that is released from membranes by low-ionic-strength-buffer treatment.

Animals↗
PubMed1984

Mice homozygous for chromosomal deletions at the albino locus region lack specific polypeptides in two-dimensional gels.

Radiation-induced chromosomal deletions involving the albino locus region of the mouse result, when homozygous, in abnormalities ranging from sterility to lethality at various stages of development. We have utilized two-dimensional electrophoresis to search for polypeptide alterations in livers from newborn mice homozygous for the c14CoS and c3H deletions and also from c3H/c6H compound heterozygote mice. Five-hundred polypeptide spots detectable in normal mouse liver gels were scored. Alterations involving five polypeptides were observed in the various overlapping deletions. A spot corresponding to a polypeptide with a 38,000 Mr was missing from mice homozygous for the short c14CoS and the longer overlapping c3H deletions. Another polypeptide with a 29,000 Mr was missing from c3H homozygotes and c3H/c6H heterozygotes. A third polypeptide with a 62,000 Mr was missing only from c3H homozygotes. Two additional polypeptides were markedly increased in amount in c14CoS and c3H homozygotes. The partial overlap between the three deletions analyzed allows provisional genetic mapping of previously unknown loci for three of the five electrophoretically identifiable polypeptides expressed in newborn mouse livers. The results obtained provide a basis for studying radiation-induced deletions with two-dimensional electrophoresis gels.

Albinism↗
PubMed1984

Identification of genetic variants in erythrocyte lysate by two-dimensional gel electrophoresis.

Two-dimensional gel electrophoresis followed by silver-staining has been employed to study 27 red cell lysates for genetic variation. Forty-six polypeptides selected without respect to variability were considered suitable for scoring. Only 23 of the total of 1,242 polypeptides could not be scored unambiguously. Of the remaining 1,219 polypeptides, 38 exhibited the combination of a normal and a variant polypeptide. All variants were present in either the father or the mother of the subjects. The observed index of heterozygosity was 3.1% +/- 0.5%.

Adult↗
PubMed1983

Separation of hemoglobin types by cation-exchange high-performance liquid chromatography.

The use of a recently developed cation-exchange HPLC packing material for the separation of hemoglobin types in human blood has been investigated. Adult and newborn hemolysates from normal individuals and from subjects with hemoglobin disorders were analyzed using a weak cation carboxymethyl-bonded phase on 5-micron-particle-size silica. Elution was accomplished using a Bistris (2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-1, 3-propanediol) gradient. Seven well-resolved HbA1 fractions eluted before the major HbA peak. Hbs A1a, A1b, A1c and an HbA1 fraction that increased with aging of the hemolysates were separately eluted. HbF when present or when added to the hemolysates eluted as a distinct peak. HbA was followed by Hbs A2, S, and C when present. An early-eluting peak corresponding to Hb Bart's was identified in newborn hemolysates. It is concluded that cation-exchange HPLC provides a new tool for the reliable separation of minor hemoglobin components.

Adult↗
PubMed1983

A silent, neutral substitution detected by reverse-phase high-performance liquid chromatography: hemoglobin Beirut.

A substitution of alanine for valine at position 126 in the beta-chain of hemoglobin was discovered in a hematologically normal adult male of Lebanese extraction. The variant beta-globin was initially observed and subsequently purified by reverse-phase high-performance liquid chromatography (HPLC). Reverse-phase HPLC was also used to isolate the variant tryptic peptide of beta-T13 that has alanine replacing valine at residue 126. The discovery of hemoglobin Beirut illustrates the usefulness of reverse-phase HPLC for the detection of neutral amino acid substitutions in proteins. The ability to detect neutral substitutions in undigested proteins is pertinent to the monitoring of genetic variation in human populations.

Adult↗
PubMed1983

Two-dimensional electrophoresis of plasma polypeptides reveals "high" heterozygosity indices.

A series of 62 plasma samples have been examined for genetic variation by the technique of two-dimensional polyacrylamide gel electrophoresis followed by silver-staining of the gels. Twenty polypeptides chosen without respect to variability were considered suitable for scoring. Of the total of 1,240 polypeptides, 29 could not be scored unambiguously. Seventy-five of the remaining 1,211 exhibited the combination of a normal and a variant polypeptide. All variants were present in either the father or the mother of the subject. This index of heterozygosity (6.2 +/- 0.7%) is substantially higher than those reported by others in similar studies of human fibroblasts, lymphocytes, kidney, or brain cells.

Blood Proteins↗
PubMed1982

Two-dimensional gel electrophoresis of cell proteins in childhood leukemia, with silver staining: a preliminary report.

We have investigated the potential of two-dimensional electrophoresis for identifying differences in protein patterns between acute lymphocytic (ALL) and acute myelogenous leukemia (AML). We studied blood cells directly isolated from seven children with non-T, non-B ALL and five with AML. Solubilized proteins were electrophoresed with the ISO-DALT system and made visible by silver staining. More than 800 spots were routinely detected in individual gels. Patterns for multiple runs of the same sample were indistinguishable. Most of the prominent spots were present in gels from all 12 of the individuals studied. However, substantial variability in spot intensity was observed, even among patients in the same group. Five spots were consistently present in gels of all the AML patient, and either completely absent or substantially decreased in ALL gels. Three other spots were present in ALL but not AML gels. We conclude that this may be a useful tool for characterizing leukemic cells.

Blood Proteins↗
PubMed1982

Two-dimensional electrophoretic analysis of erythrocyte membranes.

In an effort to maximize the amount of genetic information that can be extracted from a blood sample, we investigated the use of two-dimensional polyacrylamide-gel electrophoresis (PAGE) to resolve the protein constituents of the erythrocyte membrane. Lyophilized membranes were dissolved in various concentrations of urea, NP-40 detergent, and mercaptoethanol and subjected to two-dimensional PAGE by a modification of the O'Farrell procedure, with use of the ISO-DALT apparatus. More than 600 spots were visible in silver-stained gels under conditions that excluded specific cytoskeleton protein components, including spectrin and actin. The reproducibility of the pattern depended highly on the precise composition of the solubilization mixture. Poor resolution was observed in the presence of actin and other proteins of high molecular mass (spectrin bands 1 and 2) when we used high urea concentrations that solubilized the entire erythrocyte membrane. The large number of polypeptides observed could not be attributed to proteolysis, because addition of proteolytic inhibitors to the membrane wash solutions did not alter the pattern on the gel. The pattern also did not appear to include erythrocyte cytosol proteins because, except for globin, none of five purified erythrocyte lysate proteins was visible in the erythrocyte membrane gels. We conclude that two-dimensional electrophoresis provides a powerful tool for the study of non-cytoskeletal erythrocyte membrane proteins.

Blood Proteins↗
PubMed1981

Separation of human hemoglobins by ion exchange high performance liquid chromatography.

We have investigated the use of anion exchange high performance liquid chromatography (HPLC) for hemoglobin analysis. Several gradient elution programs were developed for optimal separation of hemoglobins in hemolysates derived from newborns and from individuals with hemoglobin disorders. The high resolution achieved, coupled with the ability to carry out chromatographic analysis in an unattended mode including automatic quantitation of the separated hemoglobins indicate that this technique could be quite useful in meeting the need for efficient and accurate diagnosis of hemoglobin disorders.

Adult↗
PubMed1981

High performance liquid chromatography of hemoglobins: factors affecting resolution.

We have investigated the effect of various factors on resolution of hemoglobin mixtures by ion exchange HPLC. Small changes in the pH of start buffer had a considerable effect on the ability to separate HBs A2 and S. Complete separation of Hbs A2, S, A, Hb A1 fraction and Hb F required 30 min. gradient elution programs. Aging of the hemolysate obscured the presence of small amounts of Hb F. Deterioration in column performance was attributed to dissolution of some of the column packing material as well as irreversible binding of hemoglobin component(s) to the ion exchanger. Substantial differences in elution time were observed between different columns requiring modifications in the gradient programs with some columns. The resolution achieved makes the HPLC technique a powerful new tool for hemoglobin analysis.

Adult↗
PubMed1980

Clinical implications of recent advances in hemoglobin disorders.

The greater availability of sophisticated diagnostic procedures has led to the discovery of more than 350 abnormal human hemoglobins. Whereas most are clinically silent, in a sizeable number of variants, function anomalies and disease states. Their more clinically relevant aspects are discussed.

Anemia, Sickle Cell↗
PubMed1978

Proteolytic activity in erythrocyte precursors.

Thalassemia is characterized by unequal rates of synthesis of the alpha and beta globin chains that are part of the hemoglobin tetramer. In the type of thalassemia due to a defect in beta-chain synthesis (beta-thalassemia), this imbalance results in a relative exoess of alpha-chains. We have studied the susceptibility of excess free alpha-chains to proteolysis. Incubation of isotopically labeled peripheral blood lysates from individuals with beta-thalassemia trait in the presence of bone marrow or normoblast lysates from thalassemic or hematologically normal individuals resulted in a decrease in the alpha/beta ratio and a loss of free alpha-chain radioactivity. Neither contamination with leukocytes nor higher ATP contents in young erythrocytes appeared to be responsible for this activity in normoblasts and bone marrow. We propose that erythroid precursor cells possess proteolytic activity that is markedly diminished in mature cells. This activity serves an important control function in the regulation of hemoglobin synthesis. It accounts at least in part for the more balanced synthesis of alpha- and beta-chains observed in bone marrow than in peripheral blood in heterozygous beta-thalassemia. It also plays a fine-tuning role in maintaining balanced synthesis in non-thalassemic erythrocytes.

Adenosine Triphosphate↗
PubMed1978

Primary amyloidosis associated with Gaucher's disease.

Elevations in serum immunoglobulins, frequently monoclonal in nature, are known to occur in patients with the adult form of Gaucher's disease. We describe amyloidosis in a 46-year-old woman of Italian ancestry with Gaucher's disease, who also had 3100 mg/dl of monoclonal IgA. She died of restrictive cardiac disease. A 50-year-old sister, also with Gaucher's disease, had 1300 mg/dl of polyclonal IgM but no evidence of amyloidosis. A glucosyl sphingosine-Sepharose affinity column provided no evidence that the large amount of immunoglobulin present has specific affinity for glucosyl ceramide. This, to our knowledge, is the first report of amyloidosis complicating Gaucher's disease.

Amyloidosis↗