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Biomedical subjects

R Lüthy

Publications and source records attributed to R Lüthy.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Sinusitis in HIV infection].

Case notes of 722 HIV-infected patients who had died between March 1986 and August 1993 were analysed to evaluate the prevention and characteristic features of sinusitis associated with HIV infection. In 73 patients (10%) sinusitis had been diagnosed at least once on the basis of radiological or clear-cut clinical criteria. In addition, 15 patients with sinusitis were identified among those attending an HIV out-patient clinic. There were altogether 126 episodes of sinusitis in 88 patients (62 men, 26 women; mean age 33 [19-69] years). In 62 patients the CD4 lymphocyte count was under 100/microliters. The most commonly affected site was the maxillary sinuses. Patients with mirror formation had a significantly longer duration of illness than those without (P = 0.021). In 58 patients the symptoms of fever, headache and rhinitis were predominantly caused by the sinusitis, in 49 only partially so, and in 19 sinusitis was a chance diagnosis. In 10 of 49 attacks of sinusitis the concurrent disease (e.g. cerebral toxoplasmosis, malignant non-Hodgkin lymphoma) had not been recognized by the referring doctor. There were 1-5 recurrences over an observation period of 11.8 (0-72) months in 23 patients.-These findings show that sinusitis frequently occurs in HIV-infected patients, takes a protracted course and is difficult to distinguish from concomitant diseases by its clinical presentation. If symptoms persist, possible concurrent respiratory infection or CNS involvement must be looked for. Sinus needle aspiration is of decisive importance to ascertain the causative organism.

Adult↗
PubMed1994

[Sputum examination in the diagnosis of Pneumocystis carinii pneumonia in HIV-infected patients].

To assess the sensitivity and negative predictive value of sputum examination for Pneumocystis carinii in HIV-positive patients, follow-ups were performed in HIV-infected patients who had been investigated for the presence of Pneumocystis carinii (376 examinations of sputum and 71 bronchoalveolar lavages). Pneumocystis carinii pneumonia was diagnosed 65 times in 64 patients (57 male and 7 female, median age 35 [23-67]years). In 52% of the cases (n = 34) the pathogen was identified in the sputum, in 48% (n = 31) by means of the bronchoalveolar lavage. Of 342 negative findings in sputum examination, five were definitely false negative since the subsequent lavage yielded pneumocysts. In nine further cases Pneumocystis carinii pneumonia could not be excluded because of the course of the disease. In patients from whom sputum samples were available the sensitivity of pathogen identification was at least 70.8% and the negative predictive value at least 95.9%. Since preceding prophylaxis did not render identification in the sputum more difficult, examination of spontaneous or provoked sputum is indicated as a first hand measure in all patients infected with HIV in whom Pneumocystis carinii pneumonia is suspected.

AIDS-Related Opportunistic Infections↗
PubMed1994

Improving the sensitivity of the sequence profile method.

The sequence profile method (Gribskov M, McLachlan AD, Eisenberg D, 1987, Proc Natl Acad Sci USA 84:4355-4358) is a powerful tool to detect distant relationships between amino acid sequences. A profile is a table of position-specific scores and gap penalties, providing a generalized description of a protein motif, which can be used for sequence alignments and database searches instead of an individual sequence. A sequence profile is derived from a multiple sequence alignment. We have found 2 ways to improve the sensitivity of sequence profiles: (1) Sequence weights: Usage of individual weights for each sequence avoids bias toward closely related sequences. These weights are automatically assigned based on the distance of the sequences using a published procedure (Sibbald PR, Argos P, 1990, J Mol Biol 216:813-818). (2) Amino acid substitution table: In addition to the alignment, the construction of a profile also needs an amino acid substitution table. We have found that in some cases a new table, the BLOSUM45 table (Henikoff S, Henikoff JG, 1992, Proc Natl Acad Sci USA 89:10915-10919), is more sensitive than the original Dayhoff table or the modified Dayhoff table used in the current implementation. Profiles derived by the improved method are more sensitive and selective in a number of cases where previous methods have failed to completely separate true members from false positives.

Amino Acid Sequence↗
PubMed1994

The Swiss HIV Cohort Study: rationale, organization and selected baseline characteristics.

OBJECTIVES: This paper describes the rationale and design features of the Swiss HIV Cohort Study (SHCS) and the baseline characteristics of participants enrolled up to March 31st 1993. The objectives include epidemiological, clinical and laboratory research. DESIGN: The SHCS is a prospective cohort study of HIV infected adolescents and adults seen at the outpatient clinics of the Swiss University Hospitals in Basle, Berne, Geneva, Lausanne and Zurich and the Cantonal Hospital St. Gall. The multicentre collaboration was initiated in September 1988 by the Swiss Federal Office of Public Health. Data collected prior to this date by several participating centers using a similar protocol were included, the earliest records dating back to 1982. Follow-up visits are scheduled every 6 months. ENROLLMENT: As of March 31st 1993, 6253 participants (M: 4580, F: 1675) were included with a total of 16015 person-years of follow-up (mean 2.6 years). HIV transmission categories were 46% intravenous drug users (IDU), 32% men who had sex with men (MSM), 18% heterosexual contacts (HET) and 4% other. The proportion of MSM among male participants decreased from 62% in 1985 to 40% in 1987, to remain stable thereafter. The proportion of IDU among males was around 40% throughout, whereas in females, there was a pronounced decline from 90% IDU in 1985 to 50% in 1992. Conversely, there was a striking increase in registrations of women presumably infected by HET, from 8% in 1985 to 50% in 1992. Among men, the proportion classified as HET increased from 2% to 15%. It is estimated, that a large proportion of all Swiss AIDS patients (70%) and HIV infected individuals (32%-47%) are enrolled in the Swiss HIV Cohort Study. Losses to follow-up, however, are common. CONCLUSIONS: The SHCS serves multiple purposes as a research project, as infrastructure for multidisciplinary research and as a tool to improve patient care. Several international and national trials, post-marketing surveillances and expanded access protocols were or still are based upon its infrastructure. The large number of female participants and of participants AIDS-free at entry, make the database especially valuable.

Adolescent↗
PubMed1994

Detection of Septata intestinalis in stool specimens and coprodiagnostic monitoring of successful treatment with albendazole.

We describe two patients with AIDS and chronic diarrhea in whom the microsporidian Septata intestinalis was detected with use of light and electron microscopic coprodiagnostic techniques. The ultrastructure of the microsporidian spores found in their stool specimens was distinctly different from that of Enterocytozoon bieneusi, another intestinal microsporidian found in patients infected with human immunodeficiency virus. Electron microscopic examination of duodenal biopsy specimens available from one of the patients enabled identification of S. intestinalis and confirmed the similarity of spores found in feces and in duodenal tissue. Both patients' diarrhea stopped when they were treated with albendazole. Coprodiagnostic monitoring indicated disappearance of the parasites and allowed the diagnosis of a relapse in one patient, who responded well to a second course of treatment.

AIDS-Related Opportunistic Infections↗
PubMed1994

Levels of dapsone and pyrimethamine in serum during once-weekly dosing for prophylaxis of Pneumocystis carinii pneumonia and toxoplasmic encephalitis.

Concentrations of dapsone, monoacetyldapsone, and pyrimethamine were determined in 36 serum samples from human immunodeficiency virus-infected patients on prophylaxis with once-weekly administration of dapsone-pyrimethamine (200 mg of dapsone-75 mg of pyrimethamine). During day 1 after ingestion, median levels of 1,038 ng of dapsone per ml and 356 ng of pyrimethamine per ml were found. During days 6 to 7, the dapsone level fell to < 20 ng/ml in five of nine serum samples, but the pyrimethamine level remained elevated (125 ng/ml). Concurrent, but separately ingested, didanosine administration did not seem to decrease the drug concentrations.

Adult↗
PubMed1994

Shortcomings of chest radiography in detecting Pneumocystis carinii pneumonia.

The radiographic presentation of Pneumocystis carinii pneumonia (PCP) was studied in 93 consecutive patients to determine the frequency of normal findings on chest roentgenograms and possible correlations with clinical or laboratory findings. The roentgenograms were reviewed by two radiologists in an independent, blinded way and judged with a score distinguishing between none, interstitial, and acinar infiltrates. Discordance mainly between absent versus interstitial and interstitial versus acinar infiltrates occurred in 23% of roentgenograms and was settled by consensus. The majority of patients presented with moderate-to-mild symptoms; the combination of dyspnea, cough, and fever was present in 53%. Lactate dehydrogenase (LDH) was elevated in 63%, hypoxemia (PaO2 < 75 mm Hg) was present in 57%. Findings on chest roentgenograms were normal in 39%, whereas 36% showed interstitial and 25% acinar infiltrates. These three radiographic groups represented an increasingly severe PCP, indicated by higher LDH levels and hypoxemia (both p < 0.05). In a multivariate logistic regression, normal roentgenograms were predicted by low LDH and low peripheral blood granulocytes (p < 0.005). Mortality within 3 weeks was only 4% and correlated with the severity of infiltrates (p < 0.05). Normal roentgenograms thus corresponded to an oligosymptomatic, less severe PCP. In immunodeficient HIV-infected patients, a normal chest roentgenogram does not exclude PCP and should not distract from attaining a definite diagnosis by examination of induced sputum or bronchoalveolar lavage.

Adult↗
PubMed1993

[Disseminated tuberculosis with a multiresistant strain of Mycobacterium tuberculosis in an HIV-infected Swiss male].

Multidrug-resistant M. tuberculosis in HIV-infected people has not yet been reported in Switzerland, and there have been no nosocomial epidemics as they have recently occurred in the USA. We present the case of a 38-ear-old HIV-infected man who developed disseminated tuberculosis as AIDS-defining disease. Initially he was treated with isoniazid, pyrazinamide and rifampin. Due to the emergence of resistance to isoniazid and streptomycin, ethambutol was added for one month. Later the therapy was changed back to the initial three drugs. The patient responded well to this therapy, but five months later developed a relapse. In addition to the originally diagnosed double-drug resistance, a reduced susceptibility to rifampin appeared. Ethambutol, ciprofloxacin and amikacin were added to the original three-drug regimen. This resulted in rapid clinical improvement, although sputum cultures remained positive for M. tuberculosis two months later. This isolate was resistant to pyrazinamide. For that reason pyrazinamide was replaced by clofazimine. 14 months after diagnosis the patient died of hepatic failure. Because there was a delay in isolation of one week, 37 potentially exposed health care workers were tested by the Mantoux skin test. No conversions were observed. This case report demonstrates that tuberculosis in HIV-infected patients in Switzerland may be caused by multidrug-resistant M. tuberculosis. We propose that until the results of a susceptibility assay are known, a four-drug combination should be used initially in this patient group.

AIDS-Related Opportunistic Infections↗
PubMed1993

[Disseminated toxoplasmosis in AIDS].

Within one year a 46-year-old HIV-positive man developed Pneumocystis carinii pneumonia, candida oesophagitis and recurrent mucocutaneous herpes simplex infections. He finally developed a constant fever without any infection-localizing features. There was pancytopenia, increased activities of the transaminases, lactate dehydrogenase, amylase and lipase, as well as diffuse ST-segment changes in the ECG and discrete pulmonary infiltrates. The anti-toxoplasmosis titre was 8 IU/ml. Despite extensive diagnostic tests no firm diagnosis could be established. The pulmonary infiltrate and the fever regressed under antibiotic treatment with co-trimoxazole. Two months later his general condition deteriorated again with some disorientation and subfebrile temperature, epididymitis and renewed rise in abnormal laboratory values. For the first time computed tomography showed some punctate contrast-medium concentrations in the subcortical area and the medulla. The patient died on the same day. Histological material obtained at the time of autopsy revealed pseudocysts with Toxoplasma gondii and necrotizing inflammation in the brain, myocardium and lungs, as well as the entire gastrointestinal and urogenital tracts. In addition, cytomegalovirus infection of the lung and adrenals was demonstrated. Anti-toxoplasmosis IgG titre, determined postmortem, again registered a marked rise to 251 IU/ml. This suggests that there was reactivation of the toxoplasmosis as part of the immunosuppression process.

AIDS-Related Opportunistic Infections↗
PubMed1993

[The prognostic value of different patterns of change in the CD4 lymphocyte counts in 420 symptom-free HIV-1-infected persons].

The pattern of change over time of CD4-lymphocyte counts was investigated prospectively in 420 patients infected with HIV-1 (106 women, 314 men; mean age 34.9 [21-70] years) to assess its value in prognosticating progression to AIDS. Only those CD4-lymphocyte values were taken into account which had been measured in the asymptomatic stage of the HIV infection and before introduction of antiviral treatment. An average of 4.5 (range 3-10) measurements per person were available. Mean observation time was 2.4 years, the mean annual CD4-lymphocyte decrease was 48 cells/microliters. 121 patients (28.8%) had a fall in CD4-lymphocyte count which in the regression analysis significantly differed from zero. In this group there occurred 19 progressions to AIDS (15.7%), in contrast to only 20 (6.6%) in the 299 patients with a nonsignificant CD4 fall (P < 0.01). Multivariate analysis with the Cox regression indicated that the annual reduction in the CD4 count and the initial CD4 count were the only values of prognostic significance regarding progression to AIDS. There was no evidence that percentage and absolute CD4-lymphocyte counts had a different predictive value. When the initial CD4 count was high (> 900 cells/microliters), there was on average a steeper reduction in CD4-lymphocyte counts than when it was lower. This findings argues against a linear CD4 fall during the total period of observation. The annual CD4 fall, described with linear regression, is a prognostic criterion on its own for early recognition of those patients at a high risk of progression to AIDS while still in the asymptomatic stage of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1993

[How well do condoms protect against HIV infection?].

A review of the literature shows that condoms offer good protection against HIV infection and other sexually transmitted diseases. A series of in vitro experiments demonstrate that quality condoms made of latex are impermeable to HIV. In addition, more than 30 in vivo studies confirm that condoms are highly effective in preventing the transmission of HIV. Condom breakage or slippage is relatively uncommon (1-5%). Most condom failure probably results from incorrect or inconsistent usage. Failures may be minimized by increasing experience, choice of quality condoms and by strictly following instructions for use.

Condoms↗
PubMed1993

The interaction of antigenic peptides with the H-2Kd MHC class I molecule.

An important event in the recognition of antigen by T cells is the selective interaction of peptides with major histocompatibility complex (MHC) molecules. We have defined several critical structural features that promote the efficient interaction of antigenic peptides with the MHC class I molecule, H-2Kd. For four unrelated antigens, we found that optimal synthetic peptides were short, only 9 or 10 amino acids long. These and other H-2Kd-restricted peptides were found to share a distinct 2-residue binding motif. Two regions in the H-2Kd antigen binding site that might accommodate the motif residues were identified by analysis of Ala-substituted H-2Kd molecules. A molecular model showing the possible interaction of one antigenic peptide with the H-2Kd molecule is presented.

Amino Acid Sequence↗
PubMed1993

Predictive value of bronchoalveolar lavage in excluding a diagnosis of Pneumocystis carinii pneumonia during prophylaxis with aerosolized pentamidine.

We assessed the negative predictive value of bronchoalveolar lavage (BAL) for Pneumocystis carinii pneumonia (PCP) during prophylaxis with aerosolized pentamidine. On the basis of the assumption that undiagnosed and untreated PCP would progress and become clinically apparent, for 3 months we prospectively followed 34 consecutive cases in which BAL had not detected PCP. All patients were immunodeficient, had a symptomatic human immunodeficiency virus infection, and were evaluated for possible PCP during prophylaxis with aerosolized pentamidine. No transbronchial biopsies were performed. In 32 of 34 cases, a diagnosis of PCP could be excluded because of other definite diagnoses or improvement during the follow-up. Despite negative results of an examination of their BAL fluid, two patients received empirical treatment that was active against PCP; these patients were regarded as possibly having undiagnosed PCP. Thus, the negative predictive value of BAL alone was at least 94% (32 of 34 cases) in excluding a diagnosis of PCP during prophylaxis with aerosolized pentamidine.

AIDS-Related Opportunistic Infections↗
PubMed1993

Extrapulmonary and disseminated infections due to Mycobacterium malmoense: case report and review.

Mycobacterium malmoense is a potentially pathogenic species that was first described in 1977. During the past decade M. malmoense has been recognized with increasing frequency as a pulmonary pathogen. More than 180 cases of M. malmoense infection have been reported. Most of these infections affected a previously damaged lung. Other infection sites included the skin, lymph nodes, and bursae. Five cases of disseminated infection have been reported. The antituberculous drugs associated with the most favorable susceptibility patterns are rifampin and ethambutol. Because of the slow growth of M. malmoense on conventional, egg-based bacteriologic media, the incubation time should be > 6 weeks; special solid and liquid media are recommended. We report a case of disseminated pulmonary and gastrointestinal infection due to M. malmoense in a patient with AIDS, who was treated successfully with a combination of rifabutin (ansamycin), clofazimine, and isoniazid. In addition, we review the characteristics of extrapulmonary and disseminated infections due to M. malmoense.

AIDS-Related Opportunistic Infections↗
PubMed1993

Disseminated microsporidiosis due to Encephalitozoon hellem: pulmonary colonization, microhematuria, and mild conjunctivitis in a patient with AIDS.

Four genera of microsporidia have been associated with disease in humans, which predominantly affects immunocompromised persons. Systemic infection with a newly characterized microsporidian species, Encephalitozoon hellem, was recently reported in a patient with AIDS. This article describes a second patient with AIDS and disseminated E. hellem infection. In this case the parasite was detected in sputum, urine, and conjunctival swab specimens. Apart from recurrent mild conjunctivitis and asymptomatic microhematuria, the patient had no findings or symptoms that could be related to this parasite. Specifically, no microsporidian-associated pulmonary pathology was documented. Detection of E. hellem in the patient's sputum may have epidemiological implications in that this finding suggests transmission of microsporidia by the aerosol route. Because the patient died of unrelated complications, it remains unknown whether he was an asymptomatic carrier of microsporidia or whether microhematuria heralded early microsporidian disease, with the onset of cellular damage in the urinary tract.

AIDS-Related Opportunistic Infections↗