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Biomedical subjects

Y Assaf

Publications and source records attributed to Y Assaf.

7 recordsLinked to original sources
PubMed1986

Hemispheric brain damage in unilateral status epilepticus.

A 20-year-old woman with psychomotor seizures developed prolonged unilateral status epilepticus followed by coma, right hemiparesis, fever, liver failure, and eventually death. Neuropathological findings included severe neuronal ischemic cell change and massive brain edema, essentially restricted to the left cerebral hemisphere. Massive destruction of the hemisphere involved in epileptic activity with sparing of the contralateral hemisphere provides supportive evidence that in humans prolonged seizure activity can cause permanent brain damage.

Adult↗
PubMed1986

Hypertrophic osteoarthropathy and primary intestinal lymphoma.

Hypertrophic osteoarthropathy (HOA) in association with primary bowel disease is rare, but is usually seen in patients with chronic diarrheal states, such as Crohn's disease and ulcerative colitis. We record the first case of HOA associated with primary intestinal lymphoma in a patient who presented with chronic diarrhea.

Adult↗
PubMed1985

Predominant T cells in pleural effusion of a patient with B-cell CLL.

Pleural effusion is a relatively rare complication of chronic lymphatic leukemia (CLL). It can be the result of primary pleural involvement, central lymphatic blockage, infection or changes induced by previous irradiation or chemotherapy. When the effusion is caused by leukemic pleural infiltration, the lymphocytes are identical to those in the peripheral blood. We have recently treated a splenectomized patient with B-cell CLL who developed pleural effusion with predominant T cells. It is suggested that this might be due to a redistribution of the T cells in the recirculating lymphocytic pool in a patient who had undergone splenectomy in the past. The possible source of these cells in the pleural effusion is discussed.

B-Lymphocytes↗
PubMed1977

Mechanism of lysozyme catalysis: role of ground-state strain in subsite D in hen egg-white and human lysozymes.

The association constants for the binding of various saccharides to hen egg-white lysozyme and human lysozyme have been measured by fluorescence titration. Among these are the oligosaccharides GlcNAc-beta(1 leads to 4)-MurNAc-beta(1 leads to 4)-GlcNAc-beta(1 leads to 4)-GlcNAc, GlcNAc-beta(1 leads to 4)-MurNAc-beta(1 leads to 4)-GlcNAc-beta(1 leads to 4)-N-acetyl-D-xylosamine, and GlcNAc-beta(1 leads to 4-GlcNAc-beta(1 leads to 4)-MurNAc, prepared here for the first time. The binding constants for saccharides which must have N-acetylmuramic acid, N-acetyl-D-glucosamine, or N-acetyl-D-xylosamine bound in subsite D indicate that there is no strain involved in the binding of N-acetyl-D-glycosamine in this site, and that the lactyl group of N-acetylmuramic acid (rather than the hydroxymethyl group) is responsible for the apparent strain previously reported for binding at this subsite. For hen egg-white lysozyme, the dependence of saccharide binding on pH or on a saturating concentration of Gd(III) suggests that the conformation of several of the complexes are different from one another and from that proposed for a productive complex. This is supported by fluorescence difference spectra of the various hen egg-white lysozyme-saccharide complexes. Human lysozyme binds most saccharides studied more weakly than the hen egg-white enzyme, but binds GlcNAc-beta(1 leads to 4)-MurNAc-beta(1leads to 4)-GlcNAc-beta(1 leads to 4)-MurNAc more strongly. It is suggested that subsite C of the human enzyme is "looser" than the equivalent site in the hen egg enzyme, so that the rearrangement of a saccharide in this subsite in response to introduction of an N-acetylmuramic acid residue into subsite D destabilizes the saccharide complexes of human lysozyme less than it does the corresponding hen egg-white lysozyme complexes. This difference and the differences in the fluorescence difference spectra of hen egg-white lysozyme and human lysozyme are ascribed mainly to the replacement of Trp-62 in hen egg-white lysozyme by Tyr-63 in the human enzyme. The implications of our findings for the assumption of superposition and additivity of energies of binding in individual subsites, and for the estimation of the role of strain in lysozyme catalysis, are discussed.

Acetylglucosamine↗