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G Schechter

Publications and source records attributed to G Schechter.

12 recordsLinked to original sources
PubMed1989

Antigenic expression of B-cell chronic lymphocytic leukemic lymphocytes.

A flow cytometric analysis of lymphocytes in B-cell chronic lymphocytic leukemia (B-CLL) samples and in monocyte-depleted and T-cell-depleted normal peripheral blood (B-PBL) samples was undertaken using 129 reagents from the blind panel (BP) and 72 reagents from the cluster designation (CD) panel obtained from the Fourth International Leucocyte Differentiation Conference and Workshop, B-Cell Section. After determining the average mean channel fluorescence and the average percentage of positive cells for the B-CLL and the normal B-PBL preparations, a combined ratio and difference analysis was performed for each monoclonal antibody reactivity. This analysis confirmed the intense expression of class II antigens on B-CLL and the preferential expression of CD19, CD20, CD23 and CD24 antigens. In addition, three new clustered and three new unclustered antigens were also preferentially expressed on B-CLL lymphocytes. Cluster analysis of these differences suggests the existence of at least three overlapping immunophenotypic subpopulations, composed of CD19, CD20, CD21, CD22, CD23, CD24, CD75, CD76 and CDw78.

Antigens, CD↗
PubMed1988

Oscillatory potentials as a marker for dopaminergic disease.

In an effort to find electrophysiologic correlates of dopaminergic disease in man, we measured oscillatory potentials of the electroretinogram in normal and unmedicated schizophrenic subjects, and in rabbits given D1 agonist or antagonist drugs. We found highly reproducible oscillatory potentials in twelve male schizophrenics that were indistinguishable from those in nine male normal volunteers. We also found little electroretinographic difference among four rabbits given intramuscular injections of SKF 38393 (a D1 agonist) and four control animals injected with saline. However, four animals given SCH 23390 (a D1 antagonist) showed diminution of the b-wave and selective suppression of the second oscillatory potential. This effect was more prominent in oscillatory potentials generated by 5-Hz flicker than by a single flash. These rabbit data suggest that further efforts at finding clinical correlations may be worthwhile, possibly with trial of flicker oscillatory potentials, and they support the concept that different oscillatory potentials have different generators.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1987

Ring chromosome in a case of acute myelomonocytic leukemia: its significance and a review of the literature.

The presence of ring chromosomes is a rare finding in patients with de novo acute nonlymphocytic leukemia (ANLL). In this report we describe the cytogenetic abnormalities, including ring chromosomes, of a 45-year-old white male who had ANLL of the myelomonocytic type (M4). All of the leukemic cells had both a small unidentified ring and a medium-sized ring which was derived from chromosomes 2 and 11, r(2;11)(2p25;11p15q23;2q37). Four different types of rings or other structural abnormalities were derived from this medium-sized ring. A review of the literature indicated that the median survival of ANLL patients with either identified or unidentified ring chromosomes was 5 to 6 months, and that the presence of these cytogenetic abnormalities was related to a poor prognosis.

Bone Marrow↗
PubMed1985

Effects of oral scopolamine on human stimulus evaluation.

In a previous study of the effect of age on information processing, both age and stimulus complexity slowed reaction time (RT) and the latency of the P300 component of the brain event-related potential (ERP). The aim of the present study was to compare the effects of scopolamine (an anticholinergic) with the previously noted effects of age. The choice of scopolamine was prompted by current hypotheses concerning decline in cholinergic function with age. Twelve adult women were studied on a battery of tasks before and after scopolamine in oral doses of 0.0 (placebo), 0.6 and 1.2 mg. Reaction times (RT) and event-related potentials (ERP) were measured. The principal task was one that combined two levels of stimulus complexity and two levels of response difficulty to provide four subtasks. Scopolamine slowed RT and P300 as had age, but scopolamine slowed responses to simple stimuli more than responses to complex stimuli. Scopolamine effects on other tasks in the battery were small but consistent with an action of scopolamine on an early stimulus preprocessing stage that is independent of a stimulus evaluation stage that is also affected by age.

Adult↗
PubMed1982

Clinical implications of cytogenetic studies in cutaneous T-cell lymphoma (CTCL).

Detailed cytogenetic studies were performed in 41 patients with cutaneous T-cell lymphoma (CTCL): four patients had limited plaques, 13 patients had generalized plaques, eight patients had cutaneous tumors, 16 patients had generalized erythroderma, and four additional patients, who had relatively benign chronic dermatosis, served as controls. Correlating the histologic and cytogenetic results in the various tissues, it was observed that 62% of the peripheral blood specimens were cytogenetically positive but only 49% were morphologically positive; in the lymph node the ratio was 80 versus 45%, and in the bone marrow, 6 versus 3%. These studies demonstrate that chromosome abnormalities are frequently detectable before morphologic changes become apparent. Chromosome banding preparations showed extensive and wide-ranging heteroploidy; the #1 chromosome was most frequently involved in structural abnormalities while chromosomes #11, 21, and 22 were most frequently involved in numerical abnormalities. These cytogenetic findings support the impression that CTCL is a disease whose various clinical manifestations represent a chronologic sequence, with the cytogenetic findings paralleling the clinical symptoms: patients with minimal chromosomal changes had the best survival and the more extensive the chromosome abnormalities, the more advanced the clinical disease. Clone formation was seen in eight patients and this phenomenon, along with hyperdiploidy and near-tetraploidy, was associated with a poor prognosis and short survival. We conclude that CTCL progresses from an early phase with extensive chromosomal abnormalities and lack of clone formation to a terminal phase with clone selection. Cytogenetic studies can, therefore, be of significant diagnostic and prognostic value in CTCL.

Adult↗