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Biomedical subjects

A Friedmann

Publications and source records attributed to A Friedmann.

105 records · Page 6Linked to original sources
PubMed1976

Analysis of herpes simplex virus DNA synthesized in infected nuclei by chromatography on benzoylated naphthoylated DEAE cellulose columns.

The nature of the DNA molecules synthesized in nuclei of herpes simplex virus (HSV)-infected cells in vivo and in vitro was studied by chromatography on BND-cellulose columns after shearing to DNA fragments of 10 to 20 X 10(6) daltons. The incorporation of labelled precursors occurs in the DNA fragments containing single-stranded regions, presumably the replication forks. Prolongation of DNA synthesis leads to the accumulation of labelled DNA fragments that lack single-stranded sequences. Analysis of the isolated DNA fragments by density centrifugation in CSCl gradients revealed that most of the labelled DNA molecules are of virus specificity and the minority are cellular DNA fragments. Double-stranded virus DNA fragments and virus DNA fragments containing single-stranded sequences band in CSCl gradients at a density of 1-718 g/ml, the density of virion DNA. This suggests that the replicating HSV DNA molecules have the same density as the virion DNA and contain relatively little single-stranded DNA. The synthesis of HSV DNA molecules under in vitro conditions in isolated nuclei occurs by incorporation of the precursors into DNA fragments with single-stranded regions. The synthesis of cellular DNA in nuclei from hydroxyurea and cytosine arabinoside treated cells also occurs by elongation of nascent DNA chains.

Arginine↗
PubMed1975

Oncornavirus-like particles released from arginine-deprived human lymphoblastoid cell lines.

Type-C RNA tumor virus particles were released from three different human lymphoblastoid cell lines after incubation in arginine-deficient medium. The released virus-like particles were characterized by (a) their ability to band in sucrose gradients at a density of 1.16-1.18 g/ml; (b) the presence of an RNA-directed DNA polymerase activity resembling that of the oncornaviruses; and (c) isolation of cores that band at a density of 1.26-1.27 g/ml in sucrose gradients. Examination of the arginine-deprived human lymphoblastoid cell line strain P3HR-1 by electron microscopy revealed the presence of C-type particles in the intracellular spaces.

Arginine↗
PubMed1975

Electron microscopic studies on assembly of herpes simplex virus upon removal of hydroxyurea block.

The release of hydroxyurea-treated, herpes simplex virus-infected cells from the drug-induced block resulted in the prompt assembly of infectious virus. Electron microscope observations at sequential intervals following removal of the drug revealed considerable synchrony of replication. This synchrony permitted stages in the complex process of core assembly to be examined in detail. The data suggest that after partial or complete assembly the nucleoprotein enters the differentiated capsid to become enfolded.

Cell Nucleus↗
PubMed1971

Practical procedures for the purification of bacterial viruses.

The efficiencies of the various methods used for phage concentration have been compared. The two-phase concentration method (with polyethylene glycol and dextran sulfate) gave maximal recoveries of infectivity for coliphages of the T-even and T-odd series and for ribonucleic acid phages and single-stranded deoxyribonucleic acid phages. Precipitation of phages by acid gave high yields when applied to T2 and T4 phages but not with T3 and T7 coliphages. Differential centrifugation was efficient when sedimented phages were gently dispersed before repeating the centrifugation cycle. The efficiencies of the various methods have also been confirmed by electron microscope studies, which also show that the two-phase concentration method gave rise to intact phages. Zone centrifugations in sucrose gradients (12.5 to 52.5%) indicated that coliphages of the T-even series sediment faster than T-odd coliphages; they may thus be separated from each other and from empty ghosts by centrifugation at 100,000 x g for 40 min. Equilibrium centrifugation in preformed cesium chloride gradients was also useful for phage concentration and purification. This study also deals with some optical properties of purified phages; optical cross sections and absorbance ratios (at 260 and 280 nm) of the various preparations are given.

Bacteriophages↗
PubMedDate not supplied

Are we witnessing the disappearance of catatonic schizophrenia?

The decrease in the frequency of diagnosed catatonic subtypes among schizophrenic disorders as a whole during the last 50 years has long been regarded as an established fact. Until now the factors responsible for this development have been under discussion. As it is not clear if there is a true decrease or an ostensible one due to other factors such as changed diagnostic habits or neuroleptic treatment, we examined 174 consecutively admitted schizophrenic patients from three different psychiatric institutions diagnosed according to DSM-IV and Leonhard's criteria. It turned out that-depending on the diagnostic system-the rates of diagnosed catatonias were 10.3% (DSM-IV) and 25.3% (Leonhard's criteria). Comparison of the two original Leonhard cohorts (1938 to 1968, 1969 to 1986) with our own (1994 to 1999) shows a decrease in the frequency of catatonias from 35% to 25%, which-albeit statistically significant-is much less pronounced than in studies that used a narrower definition of catatonia. Here, besides sociocultural developments, the use of neuroleptics seems to effect the decrease in the frequency of catatonias in two ways: on one hand, they cause a decrease of hyperkinesia, excitement, or impulsivity; while on the other hand, they themselves produce motor abnormalities like rigidity, effects that favor the attribution of motoric symptoms to neuroleptics.

Adult↗
PubMedDate not supplied

Sibling orders of schizophrenic patients in Austria and Pakistan.

The influence of siblings on the socialization of the individual has been recognized as a fact by both psychology and sociology. The significance of sibling order for the outbreak of psychiatric diseases on the other hand is still discussed controversially. In our study, we compared the expected values and the positions actually found in the sibling order of 379 (233 males, 146 females) Austrian and 144 (101 males, 43 females) Pakistani patients diagnosed with schizophrenia according to DSM-IV (295). The position in the sibling order had no influence on the outbreak of schizophrenia in Austria; with Austrian schizophrenics, the results found were very near to the expected values. In Pakistan on the other hand, the eldest brothers from families with 2-4 siblings had a significantly higher risk of falling ill. The investigation of the composition of the sibships of schizophrenic patients also showed a high overrepresentation of men in the firstborn position in Pakistan. These facts seem to exercise influences that may either protect against the outbreak or encourage it. The differences found agree well with the fact that in Pakistan, both the gender of a child and the position in the sibling order entail different ways of treatment and different scopes of responsibility. Socialization in Austria on the other hand, at least in the recent decades, has become very uniform for both sexes, regardless of the sibling position.

Adult↗
PubMedDate not supplied

Guilt and depression: a cross-cultural comparative study.

Although nearly a century has passed since Kraepelin's investigations in Java [Cbl Nervenheilk Psychiatr 1904; 27:468-469], one crucial question regarding guilt in the course of depression has still not been decided: Is there a more or less stable connection independent of culture, or is guilt confined to certain civilisations? This study investigated this issue in 100 Pakistani and 100 Austrian out-patients diagnosed with 'major depression' according to DSM-IV by means of standardised instruments (Schedule for Affective Disorders and Schizophrenia-Life Time Version, Hamilton Rating Scale for Depression, 21-item version). The experiences of guilt were subdivided into ethical feelings (ethical anxiety and feelings of guilt) and delusions of guilt. It turned out that ethical feelings could be found in both cultures regardless of age and sex. They seem to be primarily related to the extent of depressive retardation. However, the distribution of the two subsets of ethical feelings was culture dependent. Delusions of guilt were confined to patients of the Austrian sample. So, our data qualify the exclusivity of the aforementioned two points of view and support the need for a psychopathologically differentiated approach.

Adult↗
PubMedDate not supplied

[Treatment of negative symptoms in schizophrenia with neuroleptics].

Different concepts of negative symptoms in schizophrenia are reviewed. The beneficial effects of neuroleptics are discussed. The results of a pharmacokinetic and pharmacodynamic study with Amisulpride in healthy volunteers are reported. Preliminary findings of a study with Amisulpride in schizophrenic patients with predominately negative symptoms are presented. The utility of various rating scales for documenting the clinical state of these patients during therapy, and correlations of negative symptoms with psychometric and psychophysiological data are discussed. Finally, therapeutic consequences suggested by different hypothesized etiological factors causing negative symptoms are considered.

Adult↗