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Biomedical subjects

A Levy

Publications and source records attributed to A Levy.

At least 343 records · Page 19Linked to original sources
PubMed1988

Factor D is a selective single-stranded oligodeoxythymidine binding protein.

Factor D, a protein purified from rabbit liver that selectively enhances traversal of template oligodeoxythymidine tracts by diverse DNA polymerases, was examined for the sequence specificity of its binding to DNA. Terminally [32P]-labeled oligomers with the sequence 5'-d[AATTC(N)16G]-3', N being dT, dA, dG, or dC, were interacted with purified factor D and examined for the formation of protein-DNA complexes that exhibit retarded electrophoretic mobility under nondenaturing conditions. Whereas significant binding of factor D to 5'-d[AATTC(T)16G]-3' is detected, there is no discernable association between this protein and oligomers that contain 16 contiguous moieties of dG, dA, or dC. Furthermore, factor D does not form detectable complexes with the duplexes oligo(dA).oligo(dT) or poly(dA).poly(dT). The preferential interaction of factor D with single-stranded poly(dT) is confirmed by experiments in which the polymerase-enhancing activity of this protein is protected by poly(dT) against heat inactivation two- and four-fold more efficiently than by poly(dA) or poly(dA).poly(dT), respectively.

Animals↗
PubMed1988

Organization of a complex movement: fixed and variable components of the cockroach escape behavior.

The escape behavior of the cockroach Periplaneta americana was studied by means of high speed filming (250 frames/s) and a computer-graphical analysis of the body and leg movements. The results are as follows: 1. The behavior begins with pure rotation of the body about the posteriorly located cerci, followed by rotation plus forward translation, and finally pure translation (Figs. 1, 2). 2. A consistent inter-leg coordination is used for the entire duration of the turn (Fig. 3A). At the start of the movement, five or all six legs execute their first stance phase (i.e. leg on the ground during locomotion) simultaneously. By the end of the turn the pattern has changed to the alternate 'tripod' coordination characteristic of insect walking. The change-over from all legs working together, to working alternately, occurs by means of a consistent pattern of delays in the stepping of certain legs. 3. The movements made by each leg during its initial stance phase are carried out using consistent movement components in the anterior-posterior (A-P) and the medial-lateral (M-L) axes (Fig. 4A). The movement at a particular joint in each middle leg is found to be diagnostic for the direction of turn. 4. The size and direction of a given leg's M-L movement in its initial stance phase depends on the same leg's prior A-P position (Fig. 5). No such feedback effects were seen among different legs. 5. Animals that are fixed to a slick surface on which they make slipping leg movements show the same inter-leg coordination (Fig. 3B), direction of initial stance movement (Fig. 4B) and dependence of the leg's initial M-L movement on its prior A-P position (Fig. 6), as did free-ranging animals. 6. Cockroaches that are walking at the moment they begin their escape reverse those ongoing leg movements that are contrary to escape movements. 7. These results are discussed in terms of the overall coordination of the complex movements, and in terms of the known properties of the neural circuitry for escape. Possibilities for neurobiological follow-up of certain of the findings presented here are also addressed.

Animals↗
PubMed1988

Inhibition of feeding and hoarding behaviors by phenylpropanolamine in the adult rat.

The mechanism by which phenylpropanolamine (PPA) reduces feeding and body lipid is unknown. To determine if malaise associated with PPA treatment mediates its anorexic action, the present study compared the actions of PPA on feeding and hoarding behavior with that of lithium chloride at dose levels that induce comparable conditioned taste aversions. Adult male rats were injected (IP) 30 minutes prior to a test of feeding and hoarding behavior with either 0.9% saline, 32 mg/kg lithium chloride or with 10 mg/kg, 20 mg/kg or 40 mg/kg PPA. Although 32 mg/kg lithium chloride was without effect on either feeding or hoarding behaviors, PPA significantly suppressed both behaviors. These results do not support the notion that malaise is a critical aspect of the anorexic property of PPA and that hoarding behavior may represent a sensitive index of anorexic drug potency.

Animals↗
PubMed1988

Determinants of internal migration in Israel: expected returns and risks.

"A multinomial logit model of place-to-place migration focusing on economic, geographic and demographic factors is applied to empirical data on inter-regional migration in Israel in 1980. It explains 75% of the (cross-sectional) variance in the data. The results presented in this paper depart from previous empirical work due to its industrialized context and its focus on risk aversion as a determinant of the migration decision. The results support the Harris-Todaro (1970) hypothesis, and indicate that regional similarities in the structure of industrial employment promote migration."

Asia↗
PubMed1988

Community psychiatric rehabilitation in Israel.

This paper describes the development of community-based rehabilitation services for persons with mental illness in Israel. It describes current provision for occupational, social and residential programs. It is argued that developments in all of these spheres have been both slow and piecemeal, and that they have been influenced unduly by models imported from psychiatric hospitals. The authors conclude that more adequate provision is needed, and that this should be more attuned to the philosophy and objectives of community psychiatry.

Community Mental Health Services↗
PubMed1988

Are Alzheimer patients healthier?

At an active outpatient geriatric program the gerontological team observed that Alzheimer patients appear to have fewer physical ailments than other elderly patients. To test this hypothesis, we reviewed a sample of 348 clinic patients. One hundred forty-three had a normal mental status; 75 had Alzheimer's disease as defined by DSM-III criteria; 139 had an abnormal mental status attributed to other etiologies. The number of diagnoses was compiled in each of the three groups. The average number of diagnoses in the nondemented group was 5.0 in males, 5.4 in females. In the non-Alzheimer abnormal mental status group, the average number was 5.5 in males, 4.6 in females. In contrast, the number of diagnoses in the Alzheimer group was 2.9 in males and 2.8 in females (P less than 0.0001). Cardiovascular diseases, hypertension, and cerebrovascular accidents were less frequent in the Alzheimer population. This study suggests that Alzheimer patients are physically healthier than non-Alzheimer elderly patients.

Aged↗
PubMed1988

Quantitative in-situ hybridization histochemistry of anterior pituitary hormone mRNA species in human pituitary adenomas.

We have examined the anterior pituitary hormone messenger (m) RNA species contained in biopsies of 41 pituitary tumours obtained at hypophysectomy using in-situ hybridization histochemistry. The adenoma were grouped clinically into 12 prolactinomas, 8 somatotrope adenomas, 16 non-functioning, 4 Nelson's syndrome, and 1 thyrotrope adenoma. Of these, 10 contained no detectable anterior pituitary hormone mRNA species and 11 appeared to be expressing the gene responsible for the patients' clinical state in isolation. In a number of cases the accumulation of specific mRNA species was not accompanied by an increase in the circulating levels of the corresponding hormone or subunit. Evidence of activation of more than 1 anterior pituitary hormone gene was present in 16 adenomas of which only 7 showed a pattern of activation or amplification of gene expression which would suggest deregulation of either the inositol phospholipid or cAMP second messenger pathway. It was therefore not possible from these data to postulate that isolated deregulation of a single second messenger transduction pathway is a common etiological factor in pituitary tumour formation.

Adenoma↗
PubMed1988

Quantitative in-situ hybridization histochemistry studies on growth hormone (GH) gene expression in acromegalic somatotrophs: effects of somatostatin, GH-releasing factor and cortisol.

We have examined the effects of human GH-releasing factor (1-44) (GRF), cortisol and somatostatin-(1-14) on GH gene expression in solid tissue and dispersed cells from human pituitary adenomas using quantitative in-situ hybridization histochemistry. Sections cut from tissue obtained at hypophysectomy from three acromegalic patients were hybridized to probes directed against mature alpha-subunit, GH, prolactin, pro-opiomelanocortin, TSH beta-subunit and LH beta-subunit mRNA. Only one biopsy contained GH mRNA in isolation. A second was found to coexhibit GH, prolactin and alpha-subunit mRNA, and a third was found to contain prolactin, TSH beta-subunit, alpha-subunit and LH beta-subunit mRNA, with GH mRNA below the limit of specific detection, indicating that the sample was composed of normal rather than adenomatous pituitary tissue. GH mRNA in individual dispersed cells derived from the latter declined to barely detectable levels over 287 h, both in cultures containing GRF (10 ng/ml) or GRF (10 ng/ml) plus somatostatin (10 ng/ml) and in controls, but increased fourfold in cultures containing GRF (10 ng/ml) plus cortisol (0.5 mumol/l). GH mRNA remained unchanged in both adenoma samples over 138 and 450 h, irrespective of the addition of GRF or GRF plus hydrocortisone. In these samples, somatostatin plus GRF had no consistent effect. These studies confirm that quantitative in-situ hybridization histochemistry can be used to investigate hormone gene regulation in small samples of human tissue and should enable us to define more clearly the level at which abnormal gene regulation occurs.

Acromegaly↗
PubMed1988

Quantitative in-situ hybridization histochemistry in the rat pituitary gland: effect of bromocriptine on prolactin and pro-opiomelanocortin gene expression.

The temporal effect of orally administered bromocriptine on pro-opiomelanocortin (POMC) and prolactin gene expression in male Sprague-Dawley rats was examined using in-situ hybridization histochemistry. Messenger RNA in the anterior and intermediate lobes could be clearly delineated in each section. Administration of bromocriptine resulted in a reduction in hybridization of 35S-labelled cDNA probe to prolactin mRNA from 0.69 x 10(12) to 0.29 x 10(12) copies bound/g after 150 h. POMC mRNA in the anterior lobe remained unchanged with 0.08 x 10(12) copies of probe bound/g for the duration of the experiment, while in the intermediate lobe it decreased from 2.44 x 10(12) to 0.44 x 10(12) copies of probe bound/g at 150 h. The rate of reduction in intermediate lobe POMC mRNA was similar to that of prolactin mRNA for the first 24 h but was subsequently more rapid and more profound, falling to 20% of the control value at 84 h and to 18% at 150 h.

Animals↗
PubMed1988

[Donor artificial insemination. Psychological survey of 830 couples].

830 couples who had asked for Artificial Insemination by Donor (AID) were questioned using separate questionnaires for the husband and for the wife. The questions were directed to the reactions that followed in succession to discovery of the sterility, the psychological conditions that led to choosing AID, their attitude as far as secrecy was concerned and finally their contribution to finding donors of sperm. Overall the husband-wife replies corresponded to one another. Frequently the reaction to the news that the man is sterile is a depressive one and to a lesser degree followed by troubles in sexual performance. The choice of AID is usually a decision of both members of the couple. Most couples express themselves as hesitant about adoption. Most of them said that secrecy about the procedure was an essential condition. It appears that, above all, male sterility had to be hidden from the circle in which they associated and from the child. It is this position as far as secrecy is concerned that makes it difficult for the couples to help in recruiting sperm donors.

Attitude↗