Search PubMed⌕ Search

Biomedical subjects

R Lüthy

Publications and source records attributed to R Lüthy.

At least 145 records · Page 8Linked to original sources
PubMed1987

Prevalence of HIV antibodies in groups at risk in Zürich, Switzerland.

The prevalence of HIV antibodies in various groups at risk was studied in 1,546 persons in Zürich. The prevalence was 17% (39/236) in homosexual men, 7% (13/180) in bisexual men, and 45% (14/31) and 42% (22/53) in female and male intravenous drug abusers, respectively. Heterosexual transmission appeared to be the route of infection in four seropositive persons (two women and two men) who had no homosexual contacts and were not drug abusers (4/1050).

Acquired Immunodeficiency Syndrome↗
PubMed1987

Fluorescent and photoactive probes for the study of protein kinase C.

A fluorescent diacylglycerol, 2-(12-N-dansylaminododecanoyl)-1-myristoyl-sn-glycerol (dansyl-DAG) and a photoactive diacylglycerol, 2-(12-[N-(4-azido-2-nitrophenyl)] aminododecanoyl)-1-myristoyl-sn-glycerol (azido-DAG) have been synthesized. Both have been shown to bind to protein kinase C by inhibition of phorbol dibutyrate binding. Dansyl-DAG was able to activate protein kinase C at low calcium concentrations. Stimulation of neutrophils with dansyl-DAG resulted in a large release of superoxide radicals from the cells. The physicochemical properties of dansyl-DAG and azido-DAG may allow one to label and follow specifically changes in the location of protein kinase C and to understand some aspects of its function and regulation.

Affinity Labels↗
PubMed1987

Determination of teicoplanin concentrations in serum by high-pressure liquid chromatography.

An isocratic reversed-phase high-pressure liquid chromatographic method for the determination of six components of the teicoplanin complex in biological fluid was developed. By using fluorescence detection after precolumn derivatization with fluorescamine, the assay is specific and highly sensitive, with reproducibility studies yielding coefficients of variation ranging from 1.5 to 8.5% (at 5 to 80 micrograms/ml). Response was linear from 2.5 to 80 micrograms/ml (r = 0.999); the recovery from spiked human serum was 76%. An external quality control was performed to compare this high-pressure liquid chromatographic method (H) with a standard microbiological assay (M); no significant deviation from slope = 1 and intercept = 0 was found by regression analysis (H = 1.03M - 0.45; n = 15).

Anti-Bacterial Agents↗
PubMed1986

High rate of insufficient antibody titers after single-day immunization with human diploid-cell-strain vaccine against rabies.

We examined the possibility of simplifying the currently recommended immunization schedule against rabies. Four groups of 11 healthy volunteers were each immunized with either one, two, four, or eight doses of 0.1 ml human diploid cell vaccine (HDCV) intradermally on 1 single day. Antibody titers in serum were determined using a rapid fluorescent focus inhibition test. Geometric mean antibody titers 10, 30 and 90 days after immunization were all greater than 0.5 IU/ml, which is considered protective. A dose-proportional increase in the geometric mean antibody titer was observed for all four groups. However, at each dose level, at least 1 of the 11 volunteers on day 30 and 2 of the 11 volunteers on day 90 had insufficient antibody titers less than 0.5 IU/ml. Single-day immunization against rabies with HDCV vaccine cannot be recommended because of the unacceptably high failure rate.

Adolescent↗
PubMed1986

[Transfusion-associated LAV/HTLV-III infections in Switzerland. Report of 2 cases].

Two patients developed signs of LAV/HTLV-III infection one and two years respectively after a blood transfusion. The leading symptom in one patient was generalized lymphadenopathy, while the other patient presented with Candida stomatitis. In both cases, blood transfusions administered in 1983 were found to be the only possible source of infection; one blood donor of each patient was anti-LAV/HTLV-III positive. Family members and sexual partners of the two were negative for antibodies against LAV/HTLV-III. Our findings document the first two cases of LAV/HTLV-III associated disease most probably related to blood transfusions in Switzerland.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Neopterin in AIDs, other immunodeficiencies, and bacterial and viral infections.

An increase in total urinary neopterin was observed in 12 of 13 patients with acquired immunodeficiency syndrome (AIDS), seven of 13 patients with lymphadenopathy, one of six healthy homosexual males, seven of ten adult patients with staphylococcal pneumonia, 11 of 12 children with viral infections, four of seven children with bacterial infections, and 12 of 13 children with various immune defects. Extremely high values of total urinary neopterin and monapterin were observed in severely ill patients with AIDS and those with familial hemophagocytic lymphohistiocytosis. Neopterin excretion was normal in two AIDS patients with Kaposi's sarcoma, but without opportunistic infections at that time. On reexamination of one of these patients later on, elevated neopterin values were noted. Parallel increases in neopterin and monapterin were found, whereas biopterin was usually normal. The increase in total neopterin was mainly due to 7,8-dihydroneopterin and was accompanied by an increase in 3'-hydroxysepiapterin. Increased neopterin in urine is assumed to reflect the increase in GTP pool and GTP cyclohydrolase I activity as observed in stimulated monocytes. Thus, neopterin, as a measure of the activation of the nonspecific cellular immune system, may be used diagnostically to detect allograft rejection after transplantations and to follow-up HTLV-III positive patients.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Stochastic response of human blood platelets to stimulation of shape changes and secretion.

Stopped-flow turbidimetric data indicate that platelets stimulated with low levels of thrombin undergo a shape transformation from disc to "sphere" to smaller spiny sphere that is indistinguishable from the shape change induced by ADP through different membrane receptor sites and a dissimilar receptor trigger mechanism. Under conditions where neither secretion nor aggregation occur, the extinction coefficients for total scattering by each of the three platelet forms are independent of the stimulus applied, and both reaction mechanisms can be described as stochastic (Poisson) processes in which the rate constant for the formation of the transient species is equal to the rate constant for its disappearance. This observation is independent of the shape assignment, and as the concentration of thrombin is increased and various storage organelles secrete increasing amounts of their contents into the external medium, the stochastic pattern persists. Progressively larger decreases in the extinction coefficients of the intermediate and final platelet forms, over and above those that reflect shape alterations alone, accompany or parallel the reaction induced by the higher thrombin concentrations. The excess turbidity decrease observed when full secretion occurs can be wholly accounted for by a decrease in platelet volume equal in magnitude to the fraction of the total platelet volume occupied by alpha granules. Platelet activation, as reported by the whole body light scattering of either shape changes alone or shape changes plus parallel (but not necessarily also stochastic) alpha granule secretion, thus manifests itself as a random series of transient events conceivably with its origins in the superposition of a set of more elementary stochastic processes that could include microtubule depolymerization, actin polymerization, and possibly diffusion. Although the real nature of the control mechanism remains obscure, certain properties of pooled stochastic processes suggest that a reciprocal connection between microtubule fragmentation and the assembly of actin-containing pseudopodal structures and contractile elements--processes that may exhibit reciprocal requirements for calcium--might provide a hypothetical basis for a rate-limiting step.

Adenosine Diphosphate↗
PubMed1986

Serological diagnosis of Q fever endocarditis.

The diagnosis of Q fever endocarditis cannot be made by bacterial cultures and necessitates serological identification of specific antibodies to Coxiella burnetii which stimulates mainly the production of anti-phase II antibodies during the acute disease, but primarily anti-phase I antibodies in endocarditis. Indirect microimmunofluorescence allows rapid detection of specific IgA, IgG and IgM. The results of serological analyses of 191 acute cases of Q fever were compared with those of 8 cases of Coxiella burnetii endocarditis. All sera were evaluated by complement fixation and microimmunofluorescence tests. The highest titre differences between primary Q fever and Q fever endocarditis were observed with anti-phase I IgA and IgG antibodies measured by microimmunofluorescence followed by anti-phase I antibodies measured by complement fixation tests. Antiphase I IgG and IgM titres were consistently higher than anti-phase II titres in endocarditis. The reverse is true in acute Q fever. In addition, anti-phase I IgA appeared to be diagnostic for Coxiella burnetii endocarditis. Accordingly we recommend the testing of these specific IgA, IgG, and IgM by microimmunofluorescence in cases of culture-negative endocarditis. These tests could also prove useful for following the development of Coxiella burnetii endocarditis in patients under treatment.

Antibodies, Bacterial↗
PubMed1986

[Gastrointestinal involvement in acquired immunologic deficiency syndrome (AIDS)].

The gastrointestinal tract is a major target organ of the acquired immunodeficiency syndrome. Opportunistic infections or Kaposi's sarcoma within the gastrointestinal tract are the two most frequent lesions. Diarrhoea, weight loss or odynophagy may be the presenting symptoms or signs for which a gastroenterological consultation is sought. In this report we present our own observations of patients with AIDS. Diagnostic and therapeutic aspects of this new syndrome are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1985

[HTLV-III antibodies and risk factors for healthy homosexuals in Zurich].

Sera of 100 healthy homosexual men were tested for antibodies to AIDS virus HTLV-III. Significant differences were found between 45 seropositive and 55 seronegative men, such as a higher number of sexual partners per year, more contacts with AIDS patients, positive serological markers for syphilis, and reduced skin reaction after intradermal application of 7 recall antigens.

Adult↗