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Biomedical subjects

M Neumann

Publications and source records attributed to M Neumann.

At least 19 recordsLinked to original sources
PubMed1992

[Spontaneous dissection of the internal carotid artery].

A typical case history of spontaneous dissection of the internal carotid artery is presented. In young patients with cerebral ischemia, initial pain in the affected side of the head and neck, a possible provocative mechanism and a transient or even persistent Horner's syndrome are highly suggestive. The angiographic picture of carotid artery dissection is characteristic. Spontaneous resolution is common, and recurrence rare. Surgical treatment can therefore be reserved for individual cases with recurrent ischemia and caused by emboli originating in the dissected segment of the artery.

Aortic Dissection↗
PubMed1992

[Iliac artery and aortic thromboses after percutaneous transluminal angioplasty].

Transluminal angioplasty of iliac arteries is a safe and increasingly used alternative to vascular surgery. Since, especially in this region, life-threatening complications may occur at dilatation site, indication for iliac angioplasty should be examined critically, having due regard to cardiopulmonary disease and prior abdominal procedures which may hamper emergency surgery if required. The technically more difficult catheterisation by contralateral femoral approach involves a higher risk of disseminated cholesterol embolisation due to traumatised and dislodged atheromatous plaques. The report concerns three cases with rapid aortoiliac thrombosis and widespread histologically confirmed cholesterol embolisation in connection with iliac angioplasty.

Aged↗
PubMed1992

Cellular localization of Nef expressed in persistently HIV-1-infected low-producer astrocytes.

OBJECTIVES: The characterization and localization of HIV-1 Nef highly expressed in permanently infected astrocytes (TH4-7-5) as a model for latent infection of human brain cells. DESIGN: Immunochemical methods are an appropriate tool to investigate expression and localization of cellular proteins. METHODS: Nef expression was analysed by Western blot and immunoperoxidase staining using a panel of monoclonal and polyclonal antibodies. Cellular localization studies were performed by indirect immunofluorescence and subcellular fractionation of TH4-7-5 cells. Myristoylation of Nef was investigated by immunoprecipitation of [3H]myristic acid-labelled cell extract. TH4-7-5 nef gene was cloned and amplified by polymerase chain reaction and the nef nucleotide sequence analysed. RESULTS: Reactivities of various Nef-specific antibodies with Nef antigen in TH4-7-5 cells were demonstrated by Western blot analysis. Immunofluorescence revealed cytoplasmic perinuclear staining of Nef with most antibodies. However, one monoclonal antibody against amino acids 168-175 of Nef showed intense homogeneous nuclear staining in TH4-7-5 cells. Reactivity of this Nef antibody was blocked with recombinant Nef derived from TH4-7-5 cells. After subcellular fractionation, Nef was detected in nuclear, membrane and cytosolic fractions of TH4-7-5 cells. No myristoylated Nef antigen was detectable, perhaps because of a serine residue at position 2 of the TH4-7-5 nef gene instead of the glycine residue required for myristoylation. CONCLUSIONS: Chronically HIV-1-infected astrocytoma cells with restricted virus production express different antigenic forms of Nef, which can be distinguished by their subcellular localization. Variant subcellular targeting of Nef suggests the existence of multiple activities of Nef within HIV-infected cells.

Amino Acid Sequence↗
PubMed1992

Molecular cloning of a mink prion protein gene.

Transmissible mink encephalopathy (TME) is a rare disease which is presumably transmitted to ranch-raised mink from scrapie-infected sheep offal or bovine spongiform encephalopathy-infected cattle products. Although the infectious agent of TME has not been isolated, there is circumstantial evidence that TME is caused by prions. The experimental host range of TME includes sheep, cattle, monkeys and hamsters. However, TME has never been transmitted to mice. Since experiments in transgenic animals have shown that the prion protein (PrP) gene modulates the susceptibility, incubation time and neuropathology of prion-induced disease, we have started to analyse the mink PrP gene. PrP, as deduced from a genomic DNA sequence, consists of 257 amino acids and overall shows similarity of 84 to 90% with the sequences of the PrPs of other mammalian species. It remains to be determined whether these differences in the primary structure of PrP will explain the peculiar host range of TME.

Amino Acid Sequence↗
PubMed1992

Effects of antipsychotic drugs on memory functions of schizophrenic patients.

In this research we investigated the effects of 4 antipsychotic drugs with different anticholinergic components on different memory functions of schizophrenic patients. Drugs were administered in cumulative doses and memory was tested 90 min after each drug was administered. The results show that chlorpromazine and thioridazine impaired short-term verbal memory after 6 h of sequential administration. Trifluoperazine and haloperidol improved short-term verbal memory from the third to the fifth administration. Immediate memory, long-term memory and visual short-term memory were not impaired by any drug.

Adult↗
PubMed1992

Determinants of airway response to challenge with distilled water in a population sample of children aged 7 to 10 years old.

We challenged 446 schoolchildren and measured the percent decrease in FEV1 following 10 min of tidal inhalation of UNDW. Assessment tools for respiratory symptoms and atopy were questionnaire and skin testing, respectively. A previous diagnosis of asthma was most strongly associated with a positive airway response (defined as a fall in FEV1 greater than or equal to 10 percent. A positive response was also associated with atopy, presence of cough, cough during night, or any respiratory symptom. A child's age and the prechallenge FEF75% also explained response to distilled water indicating less responsiveness for older children and those with relative greater airway diameter. For the previous diagnosis of asthma, a positive distilled water challenge test had a sensitivity of 36 percent and a specificity of 92 percent. We conclude that a significant relationship between airway response to distilled water, asthma and symptoms suggestive for asthma exists for a childhood population sample.

Asthma↗
PubMed1992

Relationship between dietary components and aspects of sleep.

To test the hypothesis that major dietary constituents are related to quantity or quality of sleep, 27 adult volunteers participated in a five-day study. Subjects completed detailed dietary logs each day, and each morning completed the St. Mary's Hospital Sleep Questionnaire. Dietary data were converted to seven major nutritional constituents and these were averaged over the 5-day period. None of the 98 correlations between diet and sleep were significant. These findings provide no support for a link between sleep and diet in adults.

Adult↗
PubMed1992

Infection of human brain cells by HIV-1: restricted virus production in chronically infected human glial cell lines.

OBJECTIVE: To study expression of HIV-1 in human glial cell lines. DESIGN: Chronically HIV-1-infected glial cell lines were established to evade potential artefacts resulting from unphysiological viral entry (i.e., transfection). These cell lines were used to study viral expression and regulation. METHODS: Chronically infected glial cell lines were established by terminal dilution cloning of human glioma cells exposed to HIV-1. Virus production and expression were assayed by measuring reverse transcriptase activity, p24-antigen levels and syncytia-inducing capacity in C8166 target cells (extracellular), or by indirect immunoperoxidase staining, immunoblot analysis, and p24- and Nef-antigen-capture enzyme-linked immunosorbent assays (intracellular). HIV-long terminal repeat (LTR)-dependent expression of the chloramphenicol acetyltransferase reporter gene was determined in transient transfection assays. RESULTS: Culture supernatant from chronically HIV-1-infected glial cells contained only low levels of virus compared with chronically HIV-infected fibroblasts and T-lymphoma cells. Detailed study of HIV-antigen expression in representative glial cell line TH4-7-5 indicated the presence of all major structural proteins, albeit at low levels, and of Vif, Tat, Rev and Nef. Intracellular levels of Nef exceeded p24-antigen levels by approximately 10-fold. Virus was recovered from TH4-7-5 cells by cocultivation with blood-derived target cells, indicating that low-level virus production is not due to defective provirus. Prominent negative regulatory element (NRE)-mediated suppression of exogenous HIV-LTR activity was observed in TH4-7-5 cells and was unequalled by chronically HIV-producing fibroblast cells or by uninfected fibroblast and glial cells. CONCLUSIONS: Our results suggest that restricted virus production by chronically infected glial cells involves LTR-mediated regulation of virus expression.

Base Sequence↗
PubMed1992

Identification of complex formation between two intracellular tyrosine kinase substrates: human c-Rel and the p105 precursor of p50 NF-kappa B.

Immune complexes of the product of the c-rel protooncogene and of p105, the p50 NF-kappa B precursor, isolated from human T-lymphoblastoid cell lines are comprised of multiple proteins. Only p105 and human c-Rel (hc-Rel) are common to complexes precipitated with antiserum directed against either p105 or hc-Rel. Both proteins are inducible by phytohemagglutinin (PHA) and phorbol 12-myristate 13-acetate (PMA) and their subcellular distribution is affected by this induction. We demonstrate that the Rel immune complex contains a protein with a molecular weight in the 40 kDa range (p40) which apparently is exclusively cytoplasmic. We were not able to detect p40 in the p105 immune complex, though hc-Rel is present. This indicates that hc-Rel exists in different multi-protein complexes and fits a model of functional regulation mediated by differential protein-protein interaction. We also demonstrate considerable isoform diversity of both hc-Rel and p105. We show that this heterogeneity is, in part, the result of phosphorylation. Furthermore, we demonstrate that p105 and hc-Rel are tyrosine kinase substrates. This finding indicates a role for both proteins in intracellular signal transduction pathways which are modulated by modification of their phosphorylation status.

Humans↗
PubMed1991

[The influence of autonomic diabetic neuropathy and human atrial natriuretic peptide on adrenal gland function in postural changes].

To investigate the influence of postural changes on plasma renin activity (PRA), plasma levels of human atrial natriuretic peptide (hANP) and on aldosterone in diabetes mellitus and autonomic neuropathy, ten patients with diabetes mellitus and autonomic neuropathy and ten patients with diabetes mellitus but without autonomic neuropathy were studied. Ten healthy subjects served as controls. Patients and controls were in supine position for 60 minutes, then changed posture sequentially to sitting (90 minutes) and to upright position (15 minutes). In controls, PRA was increased upon sitting and in the upright position, while hANP was decreased. Patients with autonomic neuropathy differed from controls in impaired renin stimulation, whereas in patients without autonomic neuropathy PRA responses to postural changes were only slightly decreased. In both groups of patients, the normal hANP responsiveness to postural changes was lacking. There were no differences in aldosterone levels between patients and controls. In patients with high basal hANP levels due to elevated systolic blood pressure renin responses to postural changes were decreased in comparison to those patients with low basal hANP levels. Thus, in patients with diabetes mellitus increased hANP levels which are not decreased in response to upright standing may contribute to the development of hyporeninism and its sequelae.

Adult↗
PubMed1991

[Short-term psychiatric hospitalization in an emergency room unit].

Short-term psychiatric hospitalization, developed during the past 2 decades, needs thorough evaluation with regard to its advantages. It is important to be able to identify those patients who might be aided by such treatment. Therefore the psychiatric emergency room physician should have at hand a model which would enable quick and relatively accurate decisions in identifying such patients. Our work shows that they are either without previous psychiatric history or had been admitted for less than 2 months; that they had suffered from depression, anxiety, personality disorder or addiction; that they had a substantial support system; and that when they had been treated, there had been good compliance with prescribed medication. On the other hand, those who probably would not benefit from short-term psychiatric hospitalization had a history of psychiatric hospitalization of usually more than 2 months; were diagnosed as suffering from schizophrenia or affective disorder; lacked substantial family support; and had poor compliance with medication. This data may aid the physician during the initial interview in the psychiatric emergency room in deciding on further treatment. We also found that psychiatric emergency room diagnoses are usually reliable; and that those whose only diagnosis was "for observation" had a fair chance of a successful result after short-term hospitalization (discharge directly from the emergency room unit). We therefore presume that a sharper characterization of patients referred to the psychiatric emergency room may aid in tailoring the most suitable treatment for any particular patient, thus reserving short-term hospitalization only for those who would benefit the most.(ABSTRACT TRUNCATED AT 250 WORDS)

Emergency Service, Hospital↗
PubMed1991

[Tardive akathisia and tardive dyskinesia].

Akathisia and tardive dyskinesia are thought to be different entities, while tardive akathisia is considered a variant of akathisia. In the case presented, tardive akathisia first appeared when phenothiazine medication was stopped and then, following a cerebrovascular accident, tardive akathisia disappeared with the emergence of tardive dyskinesia. This case suggests the possibility of a relationship between these 2 disorders.

Aged↗
PubMed1991

A beat-by-beat analysis of electrocardiograms from cardiac transplant recipients.

A software system is described for producing a beat-by-beat analysis of the electrocardiograms from patients after heart transplantation. Pacemaker spikes are automatically detected and eliminated from the signals. R waves are located by a robust and accurate two-step algorithm. Based on the variable length of single heart beats, the Fourier coefficients of three orthogonal surface leads and of two intracardiac leads are calculated beat-by-beat. Power spectra are then obtained by combining contributions from the variable fundamental frequency and its multiples (harmonics) into fixed frequency classes of 1 Hz width and averaging over 60-120 cardiac cycles. Additionally, averaged beat-by-beat power spectra are calculated for windowed QRS complexes and T waves. As by-products, single beat quantities, such as R-R and R-T intervals, averaged signals for all leads, and the orientational autocorrelation function of the electrical vector of the heart, are obtained. Following beat-by-beat evaluation, mean values and standard deviations are obtained for all quantities.

Algorithms↗