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Biomedical subjects

R Lüthy

Publications and source records attributed to R Lüthy.

At least 127 records · Page 7Linked to original sources
PubMed1988

[Endocarditis prophylaxis with amoxicillin, clindamycin or erythromycin? Serum bacteriostatic and bactericidal effect against Streptococcus viridans].

The effectiveness of antibiotic prophylaxis against endocarditis was assessed by testing the bactericidal and bacteriostatic action in serum of 12 healthy volunteers who had taken the recommended antibiotics according to laid down guidelines. Blood was obtained from these subjects every two hours for 12 hours after oral intake of amoxicillin (3 g as a single dose), clindamycin (600 mg a single dose) or erythromycin (1.5 g plus another 0.5 g after six hours), the serum being tested against three Strep. viridans strains. Two of the three strains were "tolerant", i.e. in relation to the minimal inhibition concentration (MIC) their growth was inhibited, but--in relation to the minimal bactericidal concentration (MBC)--they were not killed. A bacteriostatic effect by amoxicillin and clindamycin was demonstrated by a micromethod against all three strains during the 12-hour period. But erythromycin did not achieve bacteriostasis in all serum samples. A bactericidal effect was demonstrated only in those samples that contained amoxicillin, and then only against the non-tolerant of the three strains. These results support the view that amoxicillin and clindamycin are effective in the prophylaxis against Strep. viridans bacteraemia because of their constant bacteriostatic effect, as measured in serum.

Amoxicillin↗
PubMed1988

Kaposi's sarcoma in AIDS patients: long-term treatment with recombinant interferon alpha-2a and chemotherapy.

We evaluated the response to therapy and outcome in patients with HIV-associated KS. Eighteen of 26 patients with newly diagnosed KS were treated continuously with IFN until progression of the disease occurred. In most patients with progressive disease, chemotherapy, usually with vinca alcaloid derivatives was instituted. Results were disappointing: 10 of 26 patients (38.5%) died after a median follow-up period of 4.5 months. Survival was shortest in patients who developed opportunistic infections, malignant lymphoma, or had a low OKT4/OKT8 ratio. Only one patient showed a complete remission and one patient had a partial remission under IFN therapy. Five additional patients had stable disease. Chemotherapy was without measureable effect on KS in patients who had progressive disease under IFN. IFN therapy was associated with various, not life-threatening adverse effects and was best tolerated by patients with a low OKT4/OKT8 ratio. Our results indicate that only a small portion of AIDS patients with KS seem to benefit from a continuous treatment with IFN.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[Mycobacterioses in patients with HIV infection].

Mycobacterial infections were confirmed in 629 HIV-infected persons (1.4%). Five patients had a generalized infection with Mycobacterium avium complex (MAC), four an extrapulmonary tuberculosis caused by Mycobacterium tuberculosis (M. tbc). In general, the tuberculosis was the first severe opportunistic infection, while infections with MAC were more frequent in patients with already manifest AIDS. Common to all patients were a septic temperature and definite shift to the left of neutrophil granulocytes. Four of five patients with MAC also had diarrhoea, and three of four with tuberculosis additionally had peripheral lymphomas. The chest x-ray films were normal in six of the nine patients. The diagnosis was made in six patients primarily by the microscopic demonstration of acid-fast bacteria in lymph node tissue or stool, in three patients by culture from blood or liver tissue. Microscopic stool examination was helpful: in three of five patients with MAC and one of two with M. tbc in the stool culture, acid-fast bacteria had already been demonstrated. In an individual case MAC infections could not be distinguished either clinically or morphologically from infections with M. tbc, but only by culture.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[HIV-associated thrombocytopenia].

Thrombocytopenia is a relatively frequent hematological complication of HIV (human immunodeficiency virus) infection. The incidence of thrombocytopenia in a cohort of 359 homo- or bisexual men with HIV infection was 3%, while it was 9% in a cohort of 321 HIV positive persons with a history of intravenous drug abuse. We followed 42 thrombocytopenic patients prospectively to study the clinical significance of thrombocytopenia in these patients. Thrombocytopenia was significantly more severe in intravenous drug abusers than in homo- or bisexual men: 52% of the drug abusers had thrombocyte counts below 10,000/mm3, compared with only 9% of the homo- or bisexual men. Symptoms of bleeding, almost always harmless skin or mucosal bleeding, were found in 45% of patients with a history of intravenous drug abuse and in 18% of the homo- or bisexual men. Life-threatening bleeding episodes did not occur during a median observation period of approximately one year. Prednisone was the most commonly used drug in symptomatic thrombocytopenia and had demonstrable effect only while being administered. After medication was stopped the thrombocyte counts usually fell to pretreatment values. Our findings suggest that therapy of HIV-associated thrombocytopenia should be reserved for severely symptomatic patients, particularly since this symptom of HIV infection rarely causes serious complications and we do not know the influence of drugs such as corticosteroids on the progression rate of HIV-infection.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[Hepatic manifestations of the acquired immunodeficiency syndrome (AIDS)].

Hepatic manifestations of acquired immunodeficiency syndrome (AIDS) were analyzed in 76 consecutive patients. Serological markers of hepatitis B were found in 84%. All instances of biopsy-proven chronic hepatitis were associated with delta infection. One patient with intestinal cryptosporidiosis had a severe cholestasis. In the majority of patients histological examination of the liver revealed non-specific alterations, but in several cases was diagnostic of mycobacterial disease. The study of liver disease in HIV-infected patients could lead to a better understanding of diseases such as chronic hepatitis B and sclerosing cholangitis.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[HIV serological parameters in the prognosis and follow-up assessment of an HIV infection].

53 individuals negative for anti-HIV by screening test and 79 individuals positive for anti-HIV were prospectively surveyed for clinical progression and by quantitatively measuring anti-p24 (antibodies against an HIV core protein), anti-gp41 (antibodies against an HIV surface protein) and HIV-(p24) antigen. The patients were classified into four categories of HIV-markers: 1. Anti-p24 in high concentrations, HIV-Ag negative, 2. anti-p24 in high concentrations, HIV-Ag positive (most often transitory only), 3. anti-p24 absent/deficient, HIV-Ag negative and 4. anti-p24 absent/deficient and HIV-AG positive. Within a minimum of 18 months, 4 of the 53 (8%) initially anti-HIV negative individuals contracted HIV infection. 17 of the 79 (22%) initially anti-HIV positive individuals showed disease progression. 8 of the patients in category 4 already had AIDS when entering the study, and 3 of the 6 (5%) remaining patients of this category developed AIDS. Amongst the 19 patients in the third category 2 individuals (11%) developed AIDS and in a further 5 (26%) individuals the disease progressed but in no case to AIDS. None of the patients of the categories 1 and 2 developed AIDS but 2 of the 10 (20%) individuals in the second category and 3 of the 29 (10%) in the first category showed disease progression but not to AIDS. In conclusion, the quantitative measurement of anti-p24 and of HIV-Ag affords prognostic pointers for the clinical outcome of HIV infection.

AIDS-Related Complex↗
PubMed1988

Comparative study on antagonistic effects of low pH and cation supplementation on in-vitro activity of quinolones and aminoglycosides against Pseudomonas aeruginosa.

The antagonistic effects of physiological levels of Ca++ and Mg++ on the in-vitro activity of aminoglycosides and quinolones against Pseudomonas aeruginosa were studied at both pH 7.4 and 5.5. Adding Mg++ and Ca++ (100 mg/l) to commercial media deficient of these cations increased the MICs and MBCs of ciprofloxacin and enoxacin four-fold (2 P less than 0.01), which was significantly less than the 16-fold increase found for gentamicin and netilmicin (2 P less than 0.01). However, the activity of both aminoglycosides and quinolones was similarly affected by reducing the pH to 5.5 (giving eight-fold increases in MICs) or by the combination of both low pH plus cation supplementation (giving 16-fold increases in MICs). These data raise the question whether antagonizing factors should be considered not only for aminoglycosides, but also for quinolones during routine susceptibility tests on P. aeruginosa.

4-Quinolones↗
PubMed1988

Enzyme-linked immunosorbent assay for diagnosis of chronic Q fever.

From 1982 through 1987 we diagnosed 13 chronic Q fever cases. Clinically these patients presented a culture-negative endocarditis, and all but two had high complement-fixing antibody titers to Coxiella burnetii phase I (reciprocal titer above 200). With the enzyme-linked immunosorbent assay (ELISA), titers of immunoglobulin G (IgG) to phases I and II of C. burnetii averaged 158,000 and 69,900, respectively, whereas they reached 300 and 3,200 in acute Q fever cases. Similarly, IgA to both phases of C. burnetii and IgM to phase I were consistently higher during chronic than acute Q fever. The serological follow-up of one patient with chronic Q fever over a 4-year period showed a good correlation between the titers of IgG and IgM antibody titers detected by ELISA and indirect fluorescent-antibody test (IFA) to both phases of C. burnetii. Few discrepancies appeared with IgA. Shortly after initiation of antibiotic treatment, a slow and steady decrease of the antibody titers to C. burnetii phases I and II was observed. The complement fixation, IFA, and ELISA tests showed the same type of antibody response. The ELISA proved to be an excellent diagnostic test for chronic Q fever. It distinguished negative from positive reactions clearly, and results were highly reproducible. The reading is objective, and the test is simple to perform and more sensitive than the IFA and complement fixation tests. The ELISA is recommended for serologic evaluation of patients with chronic Q fever.

Antibodies, Bacterial↗
PubMed1988

Identification of fluorescent glycopeptide derivatives by two consecutive high pressure liquid chromatographic procedures.

Reversed phase high pressure liquid chromatography (HPLC) was used to separate individual components of the complex glycopeptide antibiotic teicoplanin in microgram quantities with gradient elution. Each of eight different fractions was then subjected to a specific and highly sensitive HPLC method, which has been developed for the determination of teicoplanin concentrations in biological specimens. This analytical procedure includes precolumn derivatization with fluorescamine and isocratic elution. The fluorescent teicoplanin derivatives were identified by comparing their retention times in both HPLC procedures. Derivatization resulted in increased hydrophobicity and improved chromatographic separation, but the order of elution of the different compounds was not changed. The antimicrobial activity of the individual underivatized fractions correlated with their respective contents of total teicoplanin A2, whereas the pseudo-aglycone A3 appeared less active. Similar techniques have the potential to be applied to other complex glycopeptide antibiotics.

Anti-Bacterial Agents↗
PubMed1988

[Epidemiology and means of transmission of HIV infection].

Epidemiological features of HIV infection and the AIDS pandemic are described in this review. The number of AIDS cases will continue to rise for several years, despite enormous efforts to slow the spread of HIV via sexual and parenteral exposure, since virtually all adult patients who will develop AIDS within the next 3-5 years are already infected. Careful examination of AIDS patients without identified risk factors and results obtained from anonymous testing sites for HIV infection have failed to disclose any new forms of HIV transmission. The risk for health care workers to become infected through occupational exposure appears to be very small (0.1-0.4% per documented parenteral HIV-positive blood exposure). Universal precautions against mucocutaneous blood exposure are likely to reduce this risk even further.

Acquired Immunodeficiency Syndrome↗
PubMed1987

[Quantitative sensitivity determination of bacteria. Indications and methods].

The authors describe the indications for quantitative susceptibility tests and also the methods themselves (agar dilution, macrodilution, combination tests, tests for beta-lactamase production). This study forms part of a series on susceptibility methods which started with a paper on disk susceptibility testing (this journal, 1984; 114: 1079-1086).

Anti-Bacterial Agents↗
PubMed1987

Prevalence of HIV antibodies among prostitutes in Zürich, Switzerland.

The prevalence of antibodies to the human immune deficiency virus was determined in 123 prostitutes. Of 18 intravenous drug abusers 14 were anti-HIV positive, all others, with one exception, were seronegative. Neither race, nor number of clients, nor sexual practices correlated with seropositivity.

Acquired Immunodeficiency Syndrome↗