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Biomedical subjects

A Furst

Publications and source records attributed to A Furst.

At least 37 records · Page 2Linked to original sources
PubMed1989

Drosophila embryonic neuroblasts in culture: autonomous differentiation of specific neurotransmitters.

Isolated neuroblasts from gastrula-stage Drosophila embryos divide and differentiate in vitro to produce clonally derived clusters of neurons. Both serotonin and dopamine are expressed within these cultures in patterns that are similar to their distributions in vivo. Clusters containing serotonergic neurons are generally distinct from those with dopaminergic neurons, suggesting that different neuroblasts produce neurons with these phenotypes. The appearance of each transmitter correlates with transcription of dopa decarboxylase in the transmitter-positive cells. The developmental program leading to the appearance of either serotonergic or dopaminergic neurons is different for each transmitter type. Thus, serotonergic cells are progeny of early neuroblast divisions, whereas dopaminergics arise throughout the lineage. Inhibition of cell division, but not nuclear division, with cytochalasin B demonstrates that the expression of the serotonin phenotype requires a determined number of DNA replications. These experiments establish that neuroblasts, as soon as they are formed during early gastrulation events in Drosophila, are already determined for the subsequent expression of transmitter phenotype.

Animals↗
PubMed1989

Sore throat in family practice: comparison of blood agar throat culture with a rapid enzyme immunoassay test for diagnostic purposes.

The Ventrescreen (Ventrex) rapid enzyme immunoassay test for detecting group A streptococcal antigen directly from a throat swab was compared with conventional blood agar throat culture in the diagnosis of beta haemolytic streptococcal infection among 311 patients with a sore throat attending a large suburban Jerusalem primary care clinic. Using the throat culture as the 'gold standard' the Ventrescreen test had a sensitivity of 82%, a specificity of 50%, a positive predictive value of 49%, and a negative predictive value of 82% for beta haemolytic streptococcal infection. These results are not good enough for the test to be considered a reliable substitute for throat culture in such a setting. The negative predictive value, however, supports the use of a negative test result to identify those patients in whom antibiotic therapy could be withheld until the result of their throat culture became available. These conclusions are at variance with recommendations from other studies of similar tests in different population groups, and stress the need for the careful evaluation, especially in primary care clinics, of any such rapid test which claims to be able to replace throat culture in the detection of beta haemolytic streptococcal infection.

Enzyme-Linked Immunosorbent Assay↗
PubMed1989

A new, short family function assessment questionnaire for use in family medical practice in Israel: construction, validation and preliminary application.

This report describes the compilation and initial steps in the field testing of a new questionnaire intended for Israeli family physicians wishing to rapidly assess the general level of family functioning of their patients as part of everyday routine history taking in practice. The questionnaire was shown to have reasonable reliability and validity in a nonrepresentative sample of 140 married Israeli adults in three different family medicine practices. The questionnaire yielded a sum score ranging from 0 to 20. Preliminary estimates, based on a comparison of the sum score of each patient's questionnaire with the doctor's assessment of the family's functioning, suggest that patients of families with poor function score 11 or less, with satisfactory function 12 to 17, and with good function more than 17. These ranges require further refinement and standardization by testing the questionnaire among other groups of the Israeli population.

Adult↗
PubMed1988

Acute toxicity of cadmium and zinc in the earthworm (Lumbricus terrestris).

Studies are continuing to explore the use of the earthworm (Lumbricus terrestris) for the determination of the acute toxicity of metal compounds. Worms were injected intraperitoneally with cadmium and zinc chlorides, and also zinc chloride followed by cadmium chloride to see if zinc could protect against the toxicity of cadmium. The 48 h acute toxicity (LD50) values were 22 and 23 mg/kg for Cd and Zn respectively and 30 mg/kg for Cd after the worms were pretreated with Zn. It appears that the earthworm can be a useful test subject for obtaining preliminary information on metal toxicity.

Animals↗
PubMed1988

Transverse alternating field electrophoresis (TAFE).

The rapid development of electrophoretic technology during the past five years has given us a stream of improvements in the area of pulsed-field separation techniques. This progression has culminated in the conception of TAFE, a simple, high resolution technique providing straight lane geometry and separation of fragments up to 9 million base pairs in length. Pulsed-field techniques will unquestionably play a major role in the forthcoming analysis of the human genome by facilitating restriction mapping and cloning of large fragments. We have no doubt that TAFE will allow scientists to do this type of genetic analysis, faster and better than ever before.

Blotting, Southern↗
PubMed1987

Immunoarchitecture of the bone marrow in neutropenia: increased HNK-1 + cells define a subset of neutropenic patients.

An immunoperoxidase technique was used to examine the distribution of lymphocyte subsets in bone marrow biopsies of 15 patients with neutropenia and seven non-neutropenic controls. The bone marrow of most patients and controls had similar distributions of immune effector cells characterized by a diffuse array of predominantly cytotoxic/suppressor T-cells and occasional nodular aggregates of helper T-cells. Cells displaying the natural killer cell marker HNK-1 were sparse in controls and most neutropenic patients. However, marked increases in marrow HNK-1 + cells were identified in four of the 15 patients. Three of these patients had diffuse HNK-1 + infiltrates associated with increased Leu 4+ (OKT-3+) T-cells while one had a nodular HNK-1+ infiltrate associated with small B-cell follicles. Each of these patients had clinical features similar to those described in the large granular lymphocyte (LGL) lymphocytosis (leukemia) syndrome, but only one of four demonstrated persistently increased numbers of LGLs in the peripheral blood. Thus, this study extends the association of neutropenia and increased numbers of cells with a T/NK phenotype to include patients whose bone marrow is the only demonstrable site of involvement. Since morphologic examination of the bone marrow could not identify the bone marrows with increased HNK-1+ cells, immunologic techniques are required to detect these cases.

Agranulocytosis↗
PubMed1987

Hormetic effects in pharmacology: pharmacological inversions as prototypes for hormesis.

A biological, physiological or biochemical response to a drug at a low dose may be completely opposite to that response when a larger dose is administered. Also, a response to a single dose of an agent may shortly afterwards be completely reversed. These observations are as old as the use of medicinal preparations or alcoholic beverages. The term "pharmacological inversions" can be used to describe these phenomena. A subset of the dose-response relationship is that of "hormesis." This term, "hormesis," is often used to denote the beneficial response of an organism to a low dose of a physical or chemical agent and a detrimental response to a much larger dose. Many, but not all, of the pharmacological inversions can serve as prototypes of hormesis. Examples of the dose-time effect or the dose-response relationship (which may include the phenomenon of hormesis) can be found among these agents: alcoholic beverages, anesthetic gases, barbiturates, some tranquilizers, many vitamins, caffeine, nicotine, salicylates, enzyme inducers and some toxic metals.

Animals↗
PubMed1987

Kibbutz doctor.

Explore the source record for details and available documents.

Humans↗
PubMed1986

New principles for optimum left ventriculography.

Left ventriculography has become the single most important procedure in the evaluation of cardiac function. This study reevaluated the refinements of catheter and power injector technology to assess recommendations of past years and establish new principles for optimum ventriculography. Ventriculograms from 102 patients undergoing left heart catheterization and coronary arteriography for coronary, valvular, and myocardial heart disease served as the test sample. Three styles of #7F high-flow 110-cm pigtail catheters were utilized. One had 12 sideholes while the other two had six sideholes positioned nearer the base of the curl. Analysis of ventriculographic quality of each angiogram was performed by three of the authors independently and subsequently together. Five variables were analyzed for their effect on the diagnostic quality of the angiogram: 6-hole catheters, 12-hole catheters, volume of contrast, flow rate, and location of injection. Once these analyses were complete, the effect of combinations of these variables was tested to determine their effect on angiographic quality. The first combination included contrast volume and flow rate. The second combination compared contrast volume and flow rate when utilized with 6- or 12-hole catheters. The third combination tested the 6- and 12-hole catheters in the apex or inflow locations. A multivariate contingency analysis was used to define relationships between the variables and the quality of the angiogram obtained. As independent variables, catheter style, volume of contrast, flow rate, and location of injection did not influence angiographic quality. However, the apex as a location of injection was the single most consistently important determinant of ventricular angiographic quality.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1985

Differentiation of primary embryonic neuroblasts in purified neural cell cultures from Drosophila.

Embryonic neuroblasts of Drosophila are undifferentiated precursor cells that give rise to the central nervous system. Centrifugal elutriation has been employed to fractionate embryonic cells on the basis of size. A fraction of large cells was found to be greatly enriched for neuroblasts, whereas mesodermal precursor cells were completely excluded. This allowed a second step of purification, based upon adhesion to glass, to provide virtually pure cultures of neural cells. The cells in these cultures had the properties of neurons of the Drosophila CNS: They gave rise to ganglion-like clusters from which neurites extended on the culture substrate, and they expressed the enzyme, acetylcholinesterase, and the cell surface antigens recognized by antisera raised against horseradish peroxidase. The production of large-scale neuronal cell cultures will be useful for immunological and molecular studies of neural cell differentiation.

Animals↗
PubMed1985

Cell division cycle of cultured neural precursor cells from Drosophila.

In Drosophila neuroblast cells, which give rise to the embryonic nervous system, undergo a limited number of asymmetric cell divisions. These cell lineages result in the formation of clusters of neurons when neuroblasts are isolated and cultured. A significant proportion of these neural cell clusters (NCC) arise from individual precursor cells. The formation of NCC containing more than two neurons is repressed when DNA synthesis is inhibited. Cell division during NCC development was examined by [3H]thymidine autoradiography. The pattern of DNA synthesis by neural cells was that expected based on observations in situ. The pattern in individual NCC was consistent with single precursor origins for more than 80% of NCC, under our conditions of culture. Based on this, we show that the largest neural precursors at gastrulation undergo the most cell divisions in culture. The neuroblast cell division cycle averages approximately 1.5 hr, and is similar to that of blastoderm cells.

Animals↗