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Biomedical subjects

M Shohat

Publications and source records attributed to M Shohat.

At least 181 records · Page 10Linked to original sources
PubMed1983

On the classification of nucleated red blood cells.

Bone marrow smears stained with Giemsa were scanned with a video camera under computer control. Red cells (89 normal and 44 megaloblastic) were sampled. Each cell was digitized into 70 X 70 pixels, each pixel representing a square area of 0.04 micron 2 in the original image. The pixel gray values ranged between 0-255. Zero stood for white and 255 represented black, while the numbers in between stood for the various shades of gray. The cells were first classified into six distinct classes, each representing a red blood cell differentiation state. The canonical discrimination functions derived from this classification were then utilized for grading cell differences in a continuous fashion. Each canonical discrimination function is represented in this multidimensional space by an orthogonal axis. The distance between two points (or cells) reflects their degree of similarity. By relating this measure to a reference state, it is possible to quantitate red blood cell differentiation changes. This approach is applicable to any differentiating tissue.

Anemia, Megaloblastic↗
PubMed1983

Image analysis of nucleated red blood cells.

Bone marrow smears stained with Giemsa were scanned with a video camera under computer control. Forty-two cells representing the six differentiation classes of the red bone marrow were sampled. Each cell was digitized into 70 X 70 pixels, each pixel representing a square area of 0.4 micron2 in the original image. The pixel gray values ranged between 0 and 255. Zero stood for white, 255 represented black, while the numbers in between stood for the various shades of gray. After separation and smoothing the images were processed with a Sobel operator outlining the points of steepest gray level change in the cell. These points constitute a closed curve denominated as inner cell boundary, separating the cell into an inner and an outer region. Two types of features were extracted from each cell: form features, e.g., area and length, and gray level features. Twenty-two features were tested for their discriminative merit. After selecting 16, the discriminant analysis program classified correctly all 42 cells into the 6 classes.

Azure Stains↗
PubMed1983

Retinopathy of prematurity: incidence and risk factors.

A high incidence of retinopathy of prematurity (ROP) was found in the very low-birth-weight infants discharged from the neonatal intensive care unit during the years 1977 to 1980, in spite of frequent monitoring of oxygen use. Although the yearly incidence of ROP in infants weighing less than 1,500 g varied between 35% to 36%, none were blind. The medical records of 65 infants with a birth weight between 501 and 1,250 g; surviving in 1979 to 1980, were reviewed in order to find risk factors for ROP. There were no significant differences between the 34 infants with ROP and the 31 infants who did not have ROP in mean birth weight or mean gestational age. Of 32 possible risk factors examined, the factors significantly associated with ROP were: apnea with mask and bag ventilation; prolonged parenteral nutrition; number of blood transfusions; and episodes of hypoxemia, hypercarbia, and hypocarbia. A highly significant association between hypocarbia and the development of severe ROP was found.

Apnea↗
PubMed1980

Enhanced renal tubular calcium reabsorption independent of parathormone activity, in children on long term anticonvulsant therapy.

A significant reduction in the urinary calcium-creatinine ratio, was found in thirty-four ambulatory epileptic children on long term anticonvulsant therapy, studied during wintertime. No significant difference in the urinary excretion of cyclic AMP, phosphate or amino-acids was observed when the study-group was compared to an age-matched control group. Serum calcium and phosphate values were normal, but a significant increment in alkaline phosphatase was noted. Since there was no evidence of hyperactivity of the parathormone, it is suggested that the enhanced renal tubular calcium reabsorption in children on long term anticonvulsant therapy is a nonparathormone mediated phenomenon, possibly compensating for reduced calcium absorption in the gastrointestinal tract.

Absorption↗
PubMedDate not supplied

FISH-detected delay in replication timing of mutated FMR1 alleles on both active and inactive X-chromosomes.

X-chromosome inactivation and the size of the CGG repeat number are assumed to play a role in the clinical, physical, and behavioral phenotype of female carriers of a mutated FMR1 allele. In view of the tight relationship between replication timing and the expression of a given DNA sequence, we have examined the replication timing of FMR1 alleles on active and inactive X-chromosomes in cell samples (lymphocytes or amniocytes) of 25 females: 17 heterozygous for a mutated FMR1 allele with a trinucleotide repeat number varying from 58 to a few hundred, and eight homozygous for a wild-type allele. We have applied two-color fluorescence in situ hybridization (FISH) with FMR1 and X-chromosome alpha-satellite probes to interphase cells of the various genotypes: the alpha-satellite probe was used to distinguish between early replicating (active) and late replicating (inactive) X-chromosomes, and the FMR1 probe revealed the replication pattern of this locus. All samples, except one with a large trinucleotide expansion, showed an early replicating FMR1 allele on the active X-chromosome and a late replicating allele on the inactive X-chromosome. In samples of mutation carriers, both the early and the late alleles showed delayed replication compared with normal alleles, regardless of repeat size. We conclude therefore that: (1) the FMR1 locus is subjected to X-inactivation; (2) mutated FMR1 alleles, regardless of repeat size, replicate later than wild-type alleles on both the active and inactive X-chromosomes; and (3) the delaying effect of the trinucleotide expansion, even with a low repeat size, is superimposed on the delay in replication associated with X-inactivation.

Adolescent↗
PubMedDate not supplied

A benign polymorphism in the aspartoacylase gene may cause misinterpretation of Canavan gene testing.

We found normal individuals whose aspartoacylase gene Y231X mutation site consistently gave no signal in a primer extension assay. We determined the nucleotide sequence of the relevant region of the gene in those individuals, and found a new allele with a thymidine residue at the mutation site instead of a cytidine. Since both TAC and TAT code for tyrosine, this sequence polymorphism has no effect on the amino acid sequence of the ASPA protein. We found the relative frequencies of the 693C and the 693T alleles in the tested population to be 0.75 and 0.25 respectively.

Amidohydrolases↗
PubMedDate not supplied

Cytokine profile of patients with mycosis fungoides and the immunomodulatory effect of AS101.

Cytokines are known to play a major role in the pathogenesis of mycosis fungoides, a cutaneous malignant neoplasm of CD 4 T cells. In the present study, we investigated the effect of AS101, a tellurium-based compound with immunomodulating properties, on the pattern of lymphokine production by peripheral blood mononuclear cells (PBMCs) from patients with mycosis fungoides. PBMCs were isolated from 35 patients with mycosis fungoides stage IA and IB before initiation of treatment and from 20 healthy sex and age-matched controls. Unstimulated and phytohaemagglutinin-stimulated PBMCs were tested with and without the addition of AS101. The production of interferon-gamma, interleukin 2 (IL-2), IL-2 receptor (IL-2R), interleukin 5 (IL-5) and interleukin 10 (IL-10) was determined by enzyme-linked immunosorbent assays. The effects of AS-101 on mycosis fungoides PBMCs were compared to those of healthy donor PBMCs. Significantly higher levels of IL-2R, IL-5 and IL-10 and significantly lower levels of interferon-gamma were found in the patients compared to the controls. There was no significant difference between the groups in the production of IL-2. AS101 inhibited the production of IL-2R, IL-5 and IL-10 and induced a significant increase in IL-2 levels in the mycosis fungoides PBMCs. These findings may have important clinical implications for the possible therapeutic benefit of AS101 in mycosis fungoides.

Adjuvants, Immunologic↗
PubMedDate not supplied

Protein electrophoretic markers in Israel: compilation of data and genetic affinities.

BACKGROUND: A considerable body of data has been accumulated since the 1960s on protein electrophoretic markers in the Jewish populations of Israel. However, in some Jewish communities and for some markers insufficient information has been available. In addition, studies that tried to explore the genetic affinities of various Jewish populations mainly employed antigenic markers and frequently used a small and unrepresentative number of non-Jewish populations as comparisons. AIM: The primary objectives of the present study were to create a comprehensive database for protein electrophoretic markers in Israel and thereby to explore the genetic affinities of different Jewish populations. SUBJECTS AND METHODS: Published information on red cell enzyme and serum protein polymorphisms in Israeli Jewish populations was combined with new data obtained by protein electrophoresis and DNA PCR (polymerase chain reaction) methods to create the database. The genetic affinities were investigated by two methods. Ten Jewish populations were classified in a discriminant analysis based on nine markers and 65 non-Jewish populations. The same markers and populations were also used in a genetic distance analysis. RESULTS: The database contains new information on 15 protein electrophoretic markers in 14 Israeli populations, including three Jewish populations from Turkey, Tunisia and the Caucasus region, for which no or only scarce data were previously available. The discriminant analysis resulted in only two Jewish populations, from Iraq and Yemen, being classified within the Middle Eastern group. According to their genetic distances, no particular genetic similarity was observed between the various Jewish study populations. CONCLUSIONS: In contrast to the conclusions of several previous studies, there was no evidence for close genetic affinities among the Jewish populations or for a Middle Eastern origin for most of them. Since the study is the first to use only the more reliable protein electrophoretic markers, and an appropriately comprehensive panel of non-Jewish populations, the results are regarded as the most reliable available to date.

Alleles↗
PubMedDate not supplied

Modifier locus for mitochondrial DNA disease: linkage and linkage disequilibrium mapping of a nuclear modifier gene for maternally inherited deafness.

PURPOSE: To examine the role of the nuclear genome in affecting the phenotypic expression of the simplest model of a mitochondrial DNA disease, maternally transmitted deafness. METHODS: Linkage analysis in families with maternally inherited deafness associated with the homoplasmic A1555G mutation. RESULTS: Significant linkage and linkage disequilibrium on chromosome 8 was identified. CONCLUSIONS: This finding represents the first identification of a modifier locus for a human mitochondrial DNA disease and supports the concept of mitochondrial DNA diseases having complex genetic inheritance. The eventual identification of this modifier gene will provide insights into the pathophysiological pathways determining the clinical expression of mitochondrial DNA diseases, an important step toward diagnostic and therapeutic interventions.

Cell Nucleus↗
PubMedDate not supplied

A new method for isolation of human antisperm antibodies.

A study was undertaken to isolate pure human antisperm antibodies from the sera of infertile couples. One hundred infertile couples attending the Infertility and IVF Unit (Beilinson Medical Center) because of unexplained infertility were tested (both partners) for antisperm antibodies. Sixty-eight experiments were performed with positive sera containing antisperm antibodies and normal donor sperm. These experiments were followed by experiments in order to elute pure human antisperm antibodies from the sperm surface. Three experiments were performed with human sperm which were found to be coated by antisperm antibodies, in order to directly elute these antibodies from the sperm surface. In all experiments we eluted antisperm antibodies of the IgG and IgA isotypes from the sperm surface. These antibodies were demonstrated in the eluate, in each case by either the indirect immunobead test, the radial immune diffusion assay, or the electrophoresis method. Control experiments were performed as follows: (i) normal donor sperm incubated with normal serum; (ii) normal donor sperm without serum incubation; (iii) normal donor lymphocytes incubated with serum containing antisperm antibodies; (iv) normal donor lymphocytes without serum incubation. No antisperm antibodies were obtained in any of these control experiments. Absorption and elution experiments can be used for the isolation of pure human antisperm antibodies, which may then be used for the production of anti-idiotypic antibodies to antisperm antibodies. The anti-idiotypic antibodies could be further utilized as antigen substitutes for the production of a contraceptive vaccine and/or for application in the treatment of spontaneous abortion and infertility.

Antibodies↗
PubMedDate not supplied

Plasma ammonia levels in preterm infants receiving parenteral nutrition with crystalline L-amino acids.

In order to investigate the severity and incidence of hyperammonemia in preterm infants receiving total parenteral nutrition (TPN) with crystalline L-amino acids having high arginine content (Travasol), we determined the plasma ammonia (PA) levels in a group of 29 preterm infants on TPN, weekly and 1 wk posttherapy. Their mean gestational age was 29.9 +/- 2.6 wk and mean birth weight 1208 +/- 262 g. Thirty five blood samples obtained from 15 preterm infants not on TPN with mean gestational age 32.2 +/- 1.9 wk and a birth weight of 1495 +/- 161 g served as a control. In the parenteral nutrition group the mean PA level (140 +/- 58 micrograms/100 ml) was significantly higher (p less than 0.001) than that in the same group one week post TPN (97 +/- 34 micrograms/100 ml) and in the control group (86 +/- 35 micrograms/100 ml). The incidence of hyperammonemia (greater than 160 micrograms/100 ml) was 30% in the TPN group versus 3% in the controls (p less than 0.01). Maximal PA level during that treatment was 405 versus 216 micrograms/100 ml 1 wk post-TPN versus 163 micrograms/100 ml in the controls. The data show a significant increase in PA levels in preterm infants receiving TPN with Travasol, possibly because of its high glycine content.

Ammonia↗