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Biomedical subjects

H Sass

Publications and source records attributed to H Sass.

133 records · Page 8Linked to original sources
PubMed1980

Features of in vitro puffing and RNA synthesis in polytene chromosomes of Chironomus.

In order to elucidate the causal relation between RNA synthesis and puffing in polytene chromosomes, salivary gland nuclei and chromosomes from Chironomus tentans and C. pallidivittatus (Diptera, Chironomidae) were isolated in the native state under controlled and optimized conditions. The behavior of the polytene chromatin in vitro as compared to that in vivo was studied morphologically and autoradiographically. It was shown that the absence of cytologically visible puffing does not necessarily indicate transcriptional quiescence. Under suitable conditions all potential puff sites incorporate the radioactive precursor simultaneously. This can be seen in vivo and even more clearly in chromosomes decondensed by 340-400 mM NaCl in vitro. Potential puff sites therefore appear to be permanently equipped with RNA-polymerases, and there is always a basic low level of transcriptive activity. Experimental shrinking of Balbiani rings and other puffs by dimethylsulfoxide (DMSO) or heat shock in vivo, leaves the genes in the collapsed puffs still transcriptionally active, although to a reduced extent. Light optically visible puffing is therefore not a necessary prerequisite for RNA synthesis, while, conversely, RNA synthesis is required for puff formation.

Animals↗
PubMed1977

Relationship between structure and function of antennal chemo-, hygro-, and thermoreceptive sensilla in Periplaneta americana.

On the antennae of Periplaneta americana, 25 chemo-, hygro- or thermosensitive sensilla were investigated electrophysiologically and, after marking, by transmission and scanning electron microscopy. A clear-cut relationship of functional types to structural types was observed. Two different stimulus conducting structures were observed: a) pore tubules which are found only in smooth, single-walled sensory pegs and b) secretion-filled canals which occur only in grooved double-walled sensilla. Temperature- and humidity-sensitive receptors occur only in double-walled sensilla with secretion material as the stimulus conducting system. Olfactory sensory cells were found in both types, however, those with a specific sensitivity for short-chain n-alcohols are restricted to single-walled pegs with pore tubules, while those which are most sensitive to short-chain n-acids and amines are found in double-walled sensilla, sometimes together with thermosensitive units. The stimulus conducting systems may control the access of odorous substances to the dendritic membranes and thus contribute to the discriminatory properties of the sensilla.

Animals↗
PubMedDate not supplied

Impulsivity in self-mutilative behavior: psychometric and biological findings.

This paper examines impulsivity as a central factor in moderate/superficial self-mutilation such as skin-cutting and burning. A sample of 165 subjects were divided into four groups, namely self-mutilators, patients with any modes of impulsive behavior other than self-mutilation, patients without any impulsive behavior, and normal probands. All were administered the 10th version of the Barratt Impulsiveness Scale, the State-Trait Anger Expression Inventory, and the Inventory for the Assessment of Factors of Aggressiveness. They also were interviewed carefully in regards to both impulsive and self-mutilative behavior. A d-fenfluramine challenge test was administered to 36 females and prolactin levels were measured. On the whole results implicate impulsive personality functioning as a major factor in subjects with moderate/superficial self-mutilative behavior whose trait pathology is similar to personality disordered patients with other modes of self-harming impulsive behavior.

Adult↗
PubMedDate not supplied

Circumplex models for the similarity relationships between higher-order factors of personality and personality disorders: an empirical analysis.

Similarity relationships between personality factors and personality disorders (PDs) are usually described within the conceptual framework of the "big five" model. Recently, two-dimensional circumplex models have been suggested as alternatives, such as the interpersonal circle, the multifacet circumplex, and the circumplex of premorbid personality types. The present study is an empirical investigation of the similarity relationships between the big five, the 11 DSM-III-R personality disorders and four subaffective disorders. This was performed in a sample of 165 psychiatric inpatients. We tested the extent to which the relationships could be adequately represented in two dimensions and which circumplex model can be supported by the empirical configuration. Results obtained by principal-components analysis (PCA) strongly confirm the circumplex of premorbid personality, and to some extent the multifacet circumplex. However, the interpersonal circle cannot be confirmed.

Adolescent↗
PubMedDate not supplied

Ping-pong gaze in combined intoxication with tranylcypromine, thioridazine, and clomipramine.

OBJECTIVE: This paper reports the occurrence of ping-pong gaze, a neuro-ophthalmological syndrome usually related to severe structural brain damage, in a patient intoxicated with tranylcypromine, thioridazine, and clomipramine. BACKGROUND: Although there have been some reports about the occurence of Ping-pong gaze after intoxications, it is usually related to severe bilateral hemispheric brain damage following stroke or traumatic injuries. METHOD: We report the case of a 56-year old woman who developed a neurotoxic syndrome with coma, hyperthermia, muscular rigidity, myoclonic jerks and tachycardia following an intoxication. Additionally rhythmic and pendular conjugate horizontal eye movements could be observed for three days, so that the diagnosis of ping-pong gaze was made. RESULTS: A treatment with dantrolene lead to complete remission of the neurotoxic syndrome with no signs of neurological or physical deficits. At the stage of regaining consciousness the eye movements became normal. CONCLUSION: In our case the combined intoxication with an monoamine oxidase inhibitor, a neuroleptic and a tricyclic agent lead to a neurotoxic syndrome and the occurrence of a rare neuro-ophthalmological syndrome usually related to bilateral hemispheric brain dysfunction.

Antidepressive Agents, Tricyclic↗