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Biomedical subjects

S Avraham

Publications and source records attributed to S Avraham.

63 records · Page 4Linked to original sources
PubMed1989

Molecular cloning of a cDNA that encodes the peptide core of a mouse mast cell secretory granule proteoglycan and comparison with the analogous rat and human cDNA.

A cDNA that encodes a mouse secretory granule proteoglycan peptide core was isolated from a cDNA library prepared from nontransformed mouse bone marrow-derived mast cells (BMMC) using as a probe a 280-base-pair fragment of a rat cDNA that encodes the proteoglycan peptide core of rat basophilic leukemia (RBL)-1 cells. Based on the consensus nucleotide sequence and deduced amino acid sequence of the cDNA, the mouse BMMC proteoglycan peptide core is 16.7 kDa and contains a 21-amino acid glycosaminoglycan attachment region consisting of alternating serine and glycine residues. When the predicted amino acid sequence of the mouse BMMC proteoglycan peptide core was compared with the predicted amino acid sequences of the homologous molecules expressed in RBL-1 cells and in human promyelocytic leukemia HL-60 cells, the mouse-derived sequence was more closely homologous to the rat sequence than the human sequence except for the length of the serine-glycine repeat region. The N terminus was found to be a highly conserved region of the molecule in the three species, suggesting that this region is important for the structure, function, and/or metabolism of this family of proteoglycans. Nucleotide sequences within the 5' and 3' untranslated regions of the mouse, rat, and human proteoglycan cDNA were conserved. That similar sequences were also present in the corresponding regions of a cDNA that encodes a rat mast cell protease suggests that particular nucleotide sequences may be important for regulation of expression of those proteins that are destined to reside in secretory granules.

Aggrecans↗
PubMed1989

[Epistaxis caused by leeches].

Among the conditions which can cause epistaxis are intranasal or nasopharyngeal foreign bodies. A living foreign body, or parasite, in the nose or nasopharynx is rare in western countries, but in other parts of the world is a fairly common cause of epistaxis. In the past 5 years 17 cases of epistaxis due to infestation with leeches were treated in our 2 departments. In 14 patients, 9-27 years old, the complaint was of recurrent episodes of mild epistaxis and blood-spitting several days before admission. 3 patients were admitted hemorrhaging profusely from the nose and mouth. Examination showed a green-brown mass protruding from the nasopharynx behind the soft palate, which is every case was a blood-engorged leech. Treatment consisted of removing the leech by applying a forceps to the middle of the leech's body and giving a quick pull. Bleeding ceased immediately after removal of the leech. All the patients had drunk water from brooks, streams or fresh water lakes. Therefore, in areas in which leeches are present only boiled or filtered water should be drunk.

Adolescent↗
PubMed1988

Characterization of a human eosinophil proteoglycan, and augmentation of its biosynthesis and size by interleukin 3, interleukin 5, and granulocyte/macrophage colony stimulating factor.

Human eosinophils were cultured for up to 7 days in enriched medium in the absence or presence of recombinant human interleukin (IL) 3, mouse IL 5, or recombinant human granulocyte/macrophage colony stimulating factor (GM-CSF) and then were radiolabeled with [35S]sulfate to characterize their cell-associated proteoglycans. Freshly isolated eosinophils that were not exposed to any of these cytokines synthesized Mr approximately 80,000 Pronase-resistant 35S-labeled proteoglycans which contained Mr approximately 80,000 glycosaminoglycans. RNA blot analysis of total eosinophil RNA, probed with a cDNA that encodes a proteoglycan peptide core of the promyelocytic leukemia HL-60 cell, revealed that the mRNA which encodes the analogous molecule in eosinophils was approximately 1.3 kilobases, like that in HL-60 cells. When eosinophils were cultured for 1 day or longer in the presence of 10 pM IL 3, 1 pM IL 5, or 10 pM GM-CSF, the rates of [35S]sulfate incorporation were increased approximately 2-fold, and the cells synthesized Mr approximately 300,000 Pronase-resistant 35S-labeled proteoglycans which contained Mr approximately 30,000 35S-labeled glycosaminoglycans. Approximately 93% of the 35S-labeled glycosaminoglycans bound to the proteoglycans synthesized by noncytokine- and cytokine-treated eosinophils were susceptible to degradation by chondroitinase ABC. As assessed by high performance liquid chromatography, 6-16% of these chondroitinase ABC-generated 35S-labeled disaccharides were disulfated disaccharides derived from chondroitin sulfate E; the remainder were monosulfated disaccharides derived from chondroitin sulfate A. Utilizing GM-CSF as a model of the cytokines, it was demonstrated that the GM-CSF-treated cells synthesized larger glycosaminoglycans onto beta-D-xyloside than the noncytokine-treated cells. Thus, IL 3, IL 5, and GM-CSF induce human eosinophils to augment proteoglycan biosynthesis by increasing the size of the newly synthesized proteoglycans and their individual chondroitin sulfate chains.

Cells, Cultured↗
PubMed1988

Isolation and characterization of a cDNA that encodes the peptide core of the secretory granule proteoglycan of human promyelocytic leukemia HL-60 cells.

A cDNA that encodes the peptide core of the secretory granule proteoglycan of the human promyelocytic leukemic cell line, HL-60, has been isolated and analyzed. When human genomic DNA was digested and probed under conditions of low stringency with a rat cDNA that encodes a Mr = 18,600 serine/glycine-rich proteoglycan peptide core in L2 yolk sac tumor cells (Bourdon, M. A., Oldberg, A., Pierschbacher, M., and Ruoslahti, E. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 1321-1325) and basophilic leukemia-1 cells (Avraham, S., Stevens, R. L., Gartner, M. C., Austen, K. F., Lalley, P. A., and Weis, J. H. (1988) J. Biol. Chem. 263, 7292-7296), a number of DNA fragments were identified. A HL-60 cell-derived cDNA library was therefore screened under conditions of low stringency with the rat probe to identify and isolate a human homologue of this rat proteoglycan peptide core. Analysis of the resulting human cDNA clones indicated that the proteoglycan peptide core that is expressed in HL-60 cells is Mr = 17,600 and contains an 18-amino acid glycosaminoglycan attachment region that consists primarily of alternating serin and glycine. Northern blot analysis of total RNA probed with the human cDNA revealed that the major message for this proteoglycan peptide core in HL-60 cells is approximately 1.3 kilobase pairs in size. When a Southern blot of digested human genomic DNA was probed with the human cDNA, three bands of approximately 6, 9, and 12 kilobase pairs were detected. However, when the Southern blot was probed with the XmnI----3' fragment of this human cDNA, one prominent band was detected, indicating that a single gene encodes this protein in the human. Analysis of the DNA from human/mouse and human/hamster somatic cell hybrids probed with the human cDNA demonstrated that the gene that encodes this molecule resides on human chromosome 10. Because the proteoglycans that are present in the secretory granules of different types of rat and mouse mast cells possess small peptide cores that are rich in serine and glycine, we propose that this HL-60 cell-3 derived cDNA encodes the peptide core of the proteoglycan that is expressed in the secretory granules of this human promyelocytic cell.

Amino Acid Sequence↗
PubMed1988

Isolation of a cDNA that encodes the peptide core of the secretory granule proteoglycan of rat basophilic leukemia-1 cells and assessment of its homology to the human analogue.

It has been previously shown that a single gene is used to encode the peptide core of the extracellular proteoglycan of rat L2 yolk sac tumor cells and the intracellular proteoglycan of rat basophilic leukemia (RBL)-1 cells. In order to determine if the predicted amino acid sequences of these proteoglycans are identical as well as to isolate a full length cDNA encoding a rat secretory granule proteoglycan, a cDNA library was prepared from RBL-1 cells and screened with the 165-base pair 5'----XmnI fragment of pPG-1, a partial cDNA which encodes the rat L2 cell proteoglycan peptide core. Based on the consensus nucleotide sequence of two full length RBL-1 cell-derived cDNAs, the 5' untranslated region of the mRNA that is expressed in RBL-1 cells is shorter than that expressed in the rat L2 cells although the coding regions of the mRNAs from the two cell types are identical. These findings indicate that the targeting of proteoglycans to an intracellular or extracellular compartment is a cell-specific event which is independent of the translated peptide core. Since the RBL-1 cell and the rat L2 cell proteoglycans have different types of glycosaminoglycans bound to them, it can also be concluded that the selection of the type of glycosaminoglycan that will be synthesized onto a peptide core is a cell-specific event which is not exclusively dependent on the translated peptide core. When the predicted amino acid sequence of the RBL-1 cell proteoglycan peptide core was compared to the predicted sequence of the homologous human molecule from HL-60 cells, 48% of the amino acids were identical. The N terminus was the most highly conserved area of the molecule. This region of the peptide core, which precedes the serine-glycine repeat region, is likely to be of critical importance for the biosynthesis and/or function of these proteoglycans. Analysis of 10 different mouse/hamster somatic cell hybrid lines with a SspI----3' fragment of the rat L2 cell cDNA revealed that, as in the human, the gene that encodes the mouse analogue of this peptide core resides on chromosome 10.

Amino Acid Sequence↗
PubMed1985

Missing stapes and stapes-replacing prosthesis.

Our study of 205 ears with missing stapes, secondary to some type of chronic ear disease, showed that only 40% of such ears are suitable for ossiculoplasty. The remaining 60% are unsuitable because of a fixed footplate, severe atelectasis, hearing better than 25 dB (these patients do not need the operation), or poor discrimination. A new stapes replacement prosthesis (SRP), which we term Tabor, is described for use where indicated. The prosthesis has two parts: The lower part (or base) is made of a broad inorganic, biocompatible material (Teflon). This part fits and covers most of the footplate, ensuring maximal stability. The upper part of the prosthesis is made of autograft or homograft bone--usually a malleus head--the contact of which with the drum prevents extrusion. In twelve out of fourteen ears insertion of this prosthesis was successful; the average postoperative air conduction went from 56 dB to 29 dB, leaving an average air-bone gap of 16 dB. The bone conduction also improved, from an average of 20 dB to 13 dB.

Bone Conduction↗
PubMedDate not supplied

The effect of sera from women with systemic lupus erythematosus and/or antiphospholipid syndrome on rat embryos in culture.

Women with systemic lupus erythematosus (SLE) with or without antiphospholipid antibodies (APLA) suffer from a high rate of recurrent abortions perhaps as a result of specific antibodies that may damage the conceptus. We studied the effects of sera from women with SLE--with or without--APLA and recurrent abortions on 10.5-d-old rat embryos in culture. This was compared to the results of culture on sera from control women and on rat sera. In addition, we studied sera from women with SLE with or without APLA after treatment with low doses of aspirin and glucocorticosteroids. Seventy-three percent of embryos cultured in sera from women with SLE with or without APLA were malformed in comparison to only 10.2% in embryos cultured on control sera and 5.4% in embryos cultured on rat sera. The rate of anomalies was reduced to 37.5% in embryos cultured on sera from women with SLE with or without APLA after treatment, as in 6 of 13 sera, the treatment reduced or prevented the occurrence of embryonic anomalies. When sera were divided in to low- and high-risk sera, the effect of treatment was even more significant, as the average percentage of embryonic anomalies per serum was reduced from 81.7 to 44.7%. Specific ultrastructural changes were found in the yolk sacs of the embryos cultured on the sera from women with SLE with or without APLA by transmission electron microscopy and by scanning electron microscopy. It seems that the rat embryo culture system may be an important clinical diagnostic tool to identify women with recurrent abortions in whom the etiology may be immunologic rejection of the embryo and to assess the efficacy of various treatment modalities.

Abnormalities, Drug-Induced↗