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J Cohen

Publications and source records attributed to J Cohen.

At least 1,315 records · Page 73Linked to original sources
PubMed1984

An endogenous ligand modulates dopamine-containing neurons of retina via alpha-2 adrenoceptors.

Environmental light induces the activation of dopamine (DA)-containing neurons of rat retina and as a consequence DA turnover increases. The state of DA metabolism is directly related to the content of 3,4-dihydroxyphenylacetic acid in retina. Alpha-2 adrenoceptors are present in the retina and their activation diminishes the retinal content of 3,4-dihydroxyphenylacetic acid of rats placed in the light, but not of rats placed in the dark. When alpha-2 antagonists are administered, they increase retinal DA metabolism of rats in the light as well as of rats in the dark. These results are consistent with the notion that an endogenous agonist fully occupies the alpha-2 receptor in the dark and only partially occupies the receptors in the light. The most likely endogenous agonist for these receptors is epinephrine released from a newly identified population of epinephrine-containing amacrine cells.

Animals↗
PubMed1984

AIDS--a review.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Identification of epinephrine and phenylethanolamine N-methyltransferase activity in rat retina.

Epinephrine (E) and phenylethanolamine N-methyltransferase (PNMT) are endogenous to the rat retina. The retinal enzyme shows substrate specificity and inhibitor sensitivity similar to the PNMT of brain. The E system in the retina may be part of a functional adrenergic system, because amine metabolism of dopamine-containing amacrine cells is inhibited by alpha 2 agonists and stimulated by alpha 2 antagonists.

Aging↗
PubMed1984

Repression theory: a new look at the cornerstone.

The purpose of this paper is to revise the theory of repression so as to resolve long-standing theoretical inconsistencies, to increase congruence with data and concepts generated by new clinical problems; and to contribute to analysts' understanding of patients. Our approach is based on Freud's conception of psychic structure as based on representations, which stem from needs mediated through satisfying experiences. We have also adhered to Freud's persistently held ideas of primal repression as a state with its roots in trauma, and of repression proper as a defensive process evolving out of primal repression. The most significant clinical findings are the possibility of primal repression at any stage of life, not just in childhood; and the possibility of healthy development without repression. The revised theory leads to a new general classification of analysands and clarifies the need for both components of the psychoanalytic method, resolving intrapsychic conflicts and facilitating emotional maturation. The most significant theoretical outcome is a reaffirmation of repression as the basis for any general theory of psychopathology.

Adolescent↗
PubMed1984

Glia are a unique substrate for the in vitro growth of central nervous system neurons.

We have examined the consequences of surface interactions with glial and nonglial cells on the in vitro growth of CNS neurons. When cerebellar or spinal cord cells were plated onto monolayers highly enriched in cortical astrocytes or sciatic nerve Schwann cells, neurons generally grew as single cells and showed relatively little tendency to aggregate. Similarly, neurites showed little tendency to fasciculate. In contrast, when plated onto fibroblast, heart muscle-fibroblast, or astrocyte-free meningeal monolayers, neurons rapidly aggregated, and neurite outgrowth was primarily in large fascicles. There were no glia detectable in the majority of aggregates or fascicles, suggesting that aggregation and fasciculation were due to interactions between neurons. Neurite outgrowth over 24 hr was also greater on astrocytes than on nonglia. Whether or not aggregation and fasciculation occurred was due to surface properties of the glial and nonglial cells. When neurons were added to astrocyte and nonglial monolayers growing in medium conditioned by a large excess of co-cultured nonglia or astrocytes, respectively, the pattern of neuronal growth was determined by the type of monolayer with which the neurons were in contact. Moreover, the initial growth of neurons on heat-killed astrocytes was indistinguishable from growth on living astrocytes. The pattern of neuronal growth on these different monolayers suggests that neurons are more adherent to glia than to other neurons but are more adherent to other neurons than to nonglia. Such an adherence hierarchy could explain the consistent finding of an apposition of neurons to glial surfaces during neuronal migration and axon outgrowth. Our findings also suggest that the interaction of axons with the non-neuronal milieu through which they grow may play an important role in regulating fasciculation, a process which has generally been treated as due primarily to axon-axon interactions.

Animals↗
PubMed1983

Activation of dopamine-containing amacrine cells of retina: light-induced increase of acidic dopamine metabolites.

The acidic metabolites of dopamine, homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC), are present in rat retina. DOPAC is the most abundant metabolite. Both metabolites increase in parallel when rats are taken from a dark to a lighted environment. Haloperidol treatment also increases the metabolites in both dark and light while apomorphine decreases both metabolites in dark and light and partially antagonizes the increase induced by haloperidol.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1983

Isolation of a human pararotavirus.

During a survey of 350 different isolates of human rotaviruses, a single isolate with unique properties was obtained. Unlike all rotaviruses tested this unique isolate failed to react in an ELISA test with antibody directed against the group-specific rotavirus antigen. The morphology of this unusual virus isolate was identical in electron micrographs with other rotaviruses and the virus also contained 11 double-stranded RNA segments characteristic of this virus group. The electrophoretic migration of these RNAs (electrophoretype) in polyacrylamide gels did not coincide with the typical pattern of distinct size classes observed with all human rotaviruses. The unique isolate thus had two distinct properties that distinguish it from human rotaviruses, lack of a group-specific antigen and an atypical electrophoretype of the RNA segments. Based upon this, the new human isolate is given the name pararotavirus to distinguish this new type of virus group. Porcine and chicken pararotaviruses have recently been described with similar properties.

Antigens, Viral↗
PubMed1983

Changes in red blood cell electrolyte concentrations in digitalis intoxication.

The value of red blood cell (RBC) sodium/potassium ratio in diagnosing digitalis toxicity was studied in 60 adult patients. The normal ratio was established in 34 healthy volunteers and in 10 patients with heart disease not receiving digoxin (group I). During chronic digoxin therapy, RBC sodium/potassium (Na/K) ratio and plasma digoxin were measured in 50 nontoxic patients (group II), in 10 toxic patients (group III), and in 9 of these 10 toxic patients after resolution of digoxin toxicity. Red cell sodium and RBC Na/K ratio in nontoxic patients were significantly greater than in the control group. Red cell sodium and the RBC Na/K ratio in toxic patients were significantly greater than in nontoxic patients. Despite significant group differences in these variables, however, there was considerable overlap among the subjects studied. After resolution of toxicity, red cell sodium and the RBC Na/K ratio fell to values indistinguishable from those in the nontoxic group. Although there was a statistically significant positive correlation between RBC Na/K ratio and plasma digoxin level, the RBC Na/K ratio had weak predictive value (33%) in determining digoxin toxicity. Plasma digoxin was a better predictor of digoxin toxicity (60%). The combination of plasma digoxin concentration and of RBC Na/K ratio had a higher calculated predictive value (75%), and may be more useful as an indicator of digoxin intoxication.

Adult↗
PubMed1983

Newborn neurologic maturity relates more strongly to concurrent somatic development than gestational age.

The nineteen-item assessment of newborn neurologic maturity developed by Koenigsberger was applied to 682 infants born to women enrolled in a randomized controlled trial of nutritional supplementation in a poor, urban, black, clinic population. The total score of the neurologic scale, four clusters of items derived from principal component factor analysis followed by a varimax rotation, and the four clusters taken simultaneously (using Cohen's method of set correlation) were related to the conceptional age, weight, length, and head circumference of the infants. Taken in any of these ways, neurologic maturity was more strongly related to somatic development than to conceptional age. Although these results are consistent with a set pattern and order of neurologic development, they are incompatible with such a pattern following a rigid and universal time scale. Rather, at all stages of conceptional age, there appears to be a range of neurologic maturity, related more strongly to concurrent somatic development than to the child's conceptional age.

Birth Weight↗
PubMed1983

Attention and autonomic self-regulation.

To examine how various aspects of attentional functioning are affected by autonomic self-regulation procedures, this study compared the effect of two treatment programs (EMG and thermal biofeedback used in conjunction with various somatic and cognitive relaxation/self-regulation strategies, and Benson's Relaxation Response procedure) and a Waiting List control group for essential hypertensive adults on three, perhaps overlapping, attentional dimensions: the capacity to disembed figure from ground (Embedded Figures Test, Block Design, and Picture Completion WAIS subtests); the capacity to voluntarily deploy attention (Digit Span subtest of the WAIS), and capacity to sustain attention or become absorbed (as measured by the Tellegen Absorption Scale). Thirty essential hypertensive men and women were randomly placed in one of the three groups. Attentional dimensions were assessed before and after the 10-week treatment program (or waiting period) and the relationship between blood pressure and attentional changes were assessed. The only group to evidence significant blood pressure reduction, the "Biofeedback Group," became significantly more Field Independent as measured by the EFT (p less than 0.001) and the Block Design measure (p less than 0.01) and evidenced a strong trend in the same direction on the Picture Completion measure (p less than 0.052, NS). No other significant pre-post attentional changes were found. A Pearson product correlation revealed that changes in diastolic blood pressure were significantly correlated with changes in EFT (r = 0.54, p less than 0.0001) and the Picture Completion measure (r = 0.32, p less than 0.05). The cognitive effect of autonomic self-regulation is discussed. In addition, the possible role of attention in autonomic self-regulation is examined.

Adult↗
PubMed1983

Isolation and characterization of anti-rotavirus immunoglobulins secreted by cloned hybridoma cell lines.

Five monoclonal hybridoma cell lines secreting antibodies against bovine rotavirus have been produced and four of them characterized by immunostaining of structural polypeptides electrophoretically transferred on to nitrocellulose sheets. Three hybridomas appeared to be directed against the major structural polypeptide (VP39) of the virion. These three monoclonals cross-reacted with the major polypeptide of simian rotavirus and human rotavirus. A fourth hybridoma appeared to react specifically with the high-molecular weight external polypeptide (VP89) and its cleavage products. A cross-reaction was observed with human Wa strain but not with SA11. The fifth hybridoma, even though reacting in an immunofluorescent test, did not show any reactivity by immunostaining. None of the monoclonals neutralized the infectivity of bovine rotavirus.

Antibodies, Monoclonal↗
PubMed1983

Epinephrine: a potential neurotransmitter in retina.

Dopamine (DA), norepinephrine (NE), and epinephrine (EPI) are present in rat retina. DA is the major catecholamine, whereas NE and EPI represent approximately 5% of the DA content. DA is contained in a subpopulation of amacrine cells and has been the subject of numerous studies. We investigated the origin and properties of NE and EPI in retina. Following superior cervical ganglionectomy, there was a decrease in NE content, but no decrease in EPI or phenylethanolamine-N-methyltransferase (PNMT) activity. PNMT in retina has many of the substrate-specificity and inhibitor-sensitivity characteristics of other tissues. Enzyme activity is enhanced in newborn rats by treatment with dexamethasone. Exposure to a lighted environment increases retinal EPI in normal and superior cervical ganglionectomized rats. EPI content increased for more than 2 h in a lighted environment. We conclude that most of the NE is contained within the sympathetic neurons that innervate the eye from the superior cervical ganglion, whereas EPI is contained in retinal elements that are responsive to photic stimulation.

Animals↗