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Biomedical subjects

S Avraham

Publications and source records attributed to S Avraham.

17 recordsLinked to original sources
PubMed1992

[Septic cavernous sinus thrombosis].

Septic cavernous sinus thrombosis is a rare complication of facial infections, particularly of the dangerous triangle (nose and upper lip) and less often of the orbit, middle ear, pharynx or teeth. Staphylococcus aureus is the most frequent causative agent. Prompt diagnosis and early aggressive antibiotic therapy, with or without anticoagulants, is required. A 49-year-old woman developed this complication following multiple nasal abscesses. Despite intensive antibiotic and anticoagulant therapy she became permanently blind. We present this case to stress the fact that this disease is still fraught with high morbidity, and even mortality.

Abscess↗
PubMed1992

Negative and positive cis-acting elements in the promoter of the mouse gene that encodes the serine/glycine-rich peptide core of secretory granule proteoglycans.

The gene that encodes a proteoglycan peptide core rich in serine and glycine (SG-PG) is selectively expressed by hematopoietic cells that store in their cytoplasmic granules negatively charged proteoglycans bound ionically to numerous positively charged proteins. With deletion analysis, a negative transcription regulatory element was located between residues -250 and -190 of the 5'-flanking region of the mouse SG-PG gene, and a positive regulatory element was located between residues -118 and -81. The negative regulatory element was dominantly active in fibroblasts that do not express the SG-PG gene whereas the positive regulatory element was dominantly active in hematopoietic cells that do express the SG-PG gene. Site-directed mutagenesis was used to demonstrate that the proximal element within the gene's atypical promoter resided between residues -40 and -20. As assessed by gel mobility shift analyses, the nuclei of rat basophilic leukemia-1 cells and rat-1 fibroblasts contain a number of trans-acting factors that interact with the positive and negative cis-acting regulatory elements of the SG-PG gene. Furthermore, some of these trans-acting factors appear to be different for the two cell types. These studies on cell types that do and do not express the SG-PG gene indicate that transcription of this proteoglycan peptide core gene is regulated constitutively by both positive and negative cis-acting elements located 5' of an atypical promoter.

3T3 Cells↗
PubMed1991

Cytokine mRNA are preferentially increased relative to secretory granule protein mRNA in mouse bone marrow-derived mast cells that have undergone IgE-mediated activation and degranulation.

The levels of mRNA that encode a number of cytokines have been reported by several laboratories to be increased in mouse mast cells after their IgE-bearing receptors have been cross-linked with Ag. In this study, we have compared the mRNA levels for Fc epsilon RI alpha, three cytokines (IL-6, granulocyte-macrophage CSF, and TNF-alpha), actin and three secretory granule-localized proteins (carboxypeptidase A, proteoglycan peptide core, and a generic serine protease) in mouse bone marrow-derived mast cells (BMMC) before and after IgE-mediated activation and degranulation to determine the kinetics and specificity of mRNA induction. An antigen concentration of approximately 10 ng/ml was optimal for the release of histamine from IgE-sensitized BMMC and for the generation and release of a cytokine that was functionally and immunochemically identical to TNF-alpha. In kinetic experiments, the levels of TNF-alpha, IL-6, and granulocyte-macrophage CSF mRNA increased greater than 23-fold 0.5 to 1 h after activation. As assessed by in situ hybridization, virtually all BMMC contained detectable proteoglycan peptide core mRNA before and after exposure to Ag, but only approximately one-half of the Ag-treated cells in the culture contained IL-6 mRNA 1 h after activation. There was a slight transient increase at 4 h in the level of proteoglycan peptide core mRNA, but no increase in the levels of those highly expressed mRNA that encode actin, Fc epsilon RI alpha, carboxypeptidase A, and serine protease. Thus, despite the remarkable increment in the levels of the transcripts that encode cytokines in BMMC after IgE-mediated, Ag-dependent activation, the levels of those transcripts that encode a plasma membrane-localized recognition receptor and several constituents of the secretory granule remain essentially unchanged. The failure to increase substantially the level of protease and proteoglycan peptide core mRNA in mast cells after the activation/secretion response suggests that regranulation of mast cells is a slow process.

Animals↗
PubMed1991

The effect of mastoid surgery on atelectatic ears and retraction pockets.

Forty children and 53 adults with a total of 111 atelectatic ears were operated on and followed up. Eight-four ears underwent tympanoplasty, while 27 ears underwent both a tympanoplasty and a mastoid operation. There were no statistically significant differences between the two operation groups as far as their age groups and the extent of the disease present. After follow-up of over 4 years, aeration of the middle ear was found to be better in the tympanoplasty group alone when compared with ears with also had mastoid operations.

Adolescent↗
PubMed1991

The influence of ventilating tubes on the surgical treatment of atelectatic ears.

Forty children and 53 adults having 111 atelectatic ears were operated on and followed up. All patients underwent a tympanoplasty operation, while 27 patients underwent concomitant various mastoid operations. A ventilating tube was inserted in 55 out of the 111 atelectatic ears, while in 56 ears the tympanoplasty was left without a ventilating tube. After an average of 53.1 months of post-operative follow-up we found that all ears were adequately aerated as long as a ventilating tube was in place. However, at the final check, once all ventilating tubes extruded, it was found that insertion of a ventilating tube at operation did not change the natural evolution of the atelectatic condition after surgery. Our conclusion is that the only way to overcome the atelectatic prone condition is to reinsert a ventilating tube whenever atelectasis reformation occurs.

Adolescent↗
PubMed1990

Characterization of the human gene that encodes the peptide core of secretory granule proteoglycans in promyelocytic leukemia HL-60 cells and analysis of the translated product.

Based upon the deduced amino acid sequence of a cDNA (cDNA-H4) that had been proposed to encode the peptide core of an eosinophil and a HL-60 cell secretory granule proteoglycan, a 16-amino acid peptide was synthesized. This peptide was then used to elicit rabbit antibodies for study of the translation and post-translational modification of this gene product in hematopoietic cells. When HL-60 cells were radiolabeled for 2 min with [35S]methionine, a protein that migrated in a sodium dodecyl sulfate-polyacrylamide electrophoresis gel with a Mr of 20,000 was immunoprecipitated with the IgG fraction of the anti-peptide serum. Kinetic experiments revealed that within 10 min this radiolabeled precursor protein was converted in HL-60 cells into an Mr approximately 150,000 chondroitin sulfate proteoglycan intermediate. After a 20-min to 1-h chase, this [35S]methionine- or [35S]sulfate-labeled proteoglycan intermediate lost its antigenicity, presumably due to proteolysis of its N terminus. A human genomic library was probed under conditions of high stringency with cDNA-H4 to isolate genomic clones that contain the gene that encodes this proteoglycan peptide core. This gene spans approximately 15 kilobases and consists of three exons. The first exon encodes the 5'-untranslated region of the mRNA transcript, as well as the entire 27-amino acid signal peptide of the translated molecule. The second exon encodes a 49-amino acid region of the peptide core, predicted to be the N terminus of the molecule after its proteolytic processing in the endoplasmic reticulum. The third exon encodes the remainder of the molecule, including its glycosaminoglycan attachment, serine-glycine repeat region. As assessed by S1 nuclease mapping and primer extension analysis, the transcription-initiation site in HL-60 cells for this gene resides 53 base pairs upstream from the translation-initiation site.

Amino Acid Sequence↗
PubMed1989

Cloning and characterization of the mouse gene that encodes the peptide core of secretory granule proteoglycans and expression of this gene in transfected rat-1 fibroblasts.

A mouse liver genomic library was probed with a 450-base pair AccI----3' gene-specific fragment of a mouse bone marrow-derived mast cell proteoglycan cDNA to isolate 15-18-kilobase (kb) genomic clones containing the gene that encodes the peptide core of mouse secretory granule proteoglycans. Based on the nucleotide sequences of its 2.0-3.5-kb subcloned fragments, this mouse gene consists of three exons. The first exon contains 41 base pairs of untranslated nucleotides that are present in the 5' region of the transcript and also encodes the hydrophobic 25-amino acid signal peptide. The second exon encodes a 48-amino acid sequence that would be predicted to be the N terminus of the peptide core after the signal peptide has been removed in the endoplasmic reticulum. The third exon encodes a 79-amino acid sequence that includes the 15 amino acids immediately preceding an alternating serine-glycine 21-amino acid sequence for glycosaminoglycan attachment, and the subsequent C-terminal 43 amino acids; this exon also contains the 424 untranslated nucleotides present in the 3' region of the transcript. Primer extension and S1 nuclease protection analyses were performed to determine the transcription initiation site of the mouse gene. Rat-1 fibroblasts were cotransfected with the selectable marker pSV2 neo and a lambda clone (lambda MG-PG1) to obtain two rat-1 fibroblast cell lines that had the mouse secretory granule proteoglycan gene integrated into their genomes. RNA blot analysis of both cell lines revealed the presence of the 1.0-kb secretory granule proteoglycan peptide core mRNA transcript, indicating that lambda MG-PG1 contained the entire mouse secretory granule proteoglycan peptide core gene including some of the regulatory elements in its promoter region. The gene that encodes the peptide core of mouse secretory granule proteoglycans is the first proteoglycan gene to have its complete exon/intron organization determined and to be transfected and expressed in another cell type.

Amino Acid Sequence↗
PubMed1989

A rapid procedure for cell colony hybridization using DNA probes.

A rapid, direct method for screening single cell-derived colonies or foci is described. The method allows the screening of a large number of colonies or foci by nitrocellulose filter hybridization using DNA probes. This technique simplifies current screening procedures and is a reliable, rapid, and sensitive method for the selection of cell clones containing a desired transfected gene.

Animals↗
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↗