R Lüthy

University of Zurich, Zürich, ZH, Switzerland

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Publications (103)411.17 Total impact

  • Article: Treatment-induced decline of human immunodeficiency virus-1 p24 and HIV-1 RNA in lymphoid tissue of patients with early human immunodeficiency virus-1 infection.
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    ABSTRACT: We report detailed quantitative analysis of human immunodeficiency virus-1 (HIV-1) p24 and HIV-1 RNA in tonsil biopsies from 13 patients with early, asymptomatic HIV infection before and during combination antiretroviral therapy. Using fluorescent microscopy in conjunction with reverse transcriptase-polymerase chain reaction of frozen tissue sections, we show that plasma and tissue viral loads decreased by approximately 3 logs during the 1-year treatment period, with good correlation between the HIV-1 p24 and HIV-1 RNA response in tissue. The decrease of tissue viral load was delayed compared to plasma viral load, possibly explained by the observation that the amount of follicular dendritic cell-associated virus correlated best with the area under the curve of plasma HIV-1 RNA throughout the last 12 weeks. Before and during treatment, the relative proportions of HIV-1 on follicular dendritic cells and within mononuclear cells remained constant, suggesting similar decay characteristics in these two lymphoid tissue compartments. However, viral p24 or RNA remained almost always detectable in tissue despite full suppression of HIV-1 RNA in plasma, and increased even after short-term rebounds in plasma viral load. Thus, full and sustained suppression of viral replication was required to efficiently decrease viral load in lymphoid tissue, but complete abolition of residual viral replication was not achieved.
    American Journal Of Pathology 07/2000; 156(6):1973-86. · 4.89 Impact Factor
  • Article: Human immunodeficiency virus type 1 p24 concentration measured by boosted ELISA of heat-denatured plasma correlates with decline in CD4 cells, progression to AIDS, and survival: comparison with viral RNA measurement.
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    ABSTRACT: Human immunodeficiency virus type 1 (HIV-1) RNA and p24 antigen concentrations were determined in plasma samples from 169 chronically infected patients (median CD4 cell count, 140 cells/microL; range, 0-1500 cells/microL). p24 quantification involved heat-mediated immune complex dissociation and tyramide signal amplification-boosted ELISA, which has a diagnostic sensitivity similar to that of RNA quantification by a commercial polymerase chain reaction kit. In Cox's proportional hazard models adjusted for CD4 cell count, both RNA (P<.005) and p24 (P=.043) levels were significant predictors of progression to AIDS. Measurement of p24 was superior to measurement of RNA in the model for survival (P=.032 vs. P=.19). p24 level was a significant predictor of CD4 cell decline in models adjusted for CD4 cell counts and was superior or equivalent to RNA level, depending on the group analyzed. Stratification by CD4 cell counts at baseline showed that the superiority of p24 measurement was more pronounced at lower levels of CD4 cells (<200/microL). p24 level may be of interest as a simple and inexpensive predictive marker of disease progression.
    The Journal of Infectious Diseases 04/2000; 181(4):1280-8. · 6.41 Impact Factor
  • Article: Effects of early antiretroviral treatment on HIV-1 RNA in blood and lymphoid tissue: a randomized trial of double versus triple therapy. Swiss HIV Cohort Study.
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    ABSTRACT: To assess the effects of early initiation of antiretroviral therapy on cell-free and cell-associated viral load in blood and lymphoid tissue, we performed a randomized, open-label, multicenter trial comparing a double (zidovudine + lamivudine) and triple (zidovudine + lamivudine + ritonavir) drug combination in treatment-naive, asymptomatic patients with CD4 counts >400 cells/microl. HIV-1 RNA was measured in plasma, peripheral blood mononuclear cells, and sequential tonsil or lymph node biopsies (27 patients); the study follow-up was 2 years. Among 42 randomized patients, the proportion with plasma HIV-1 RNA <50 copies/ml was 16% and 74% at week 24 (p<.001) in those randomized to double and triple therapy, respectively, necessitating frequent treatment intensification in the double arm. After a rapid decline within 4 weeks in both arms, cell-associated HIV-1 RNA decreased further only in those patients with sustained suppression of plasma viral load, but remained almost always detectable at low levels, indicating persisting transcription of viral RNA. CD4 counts increased by 200 to 250 cells/microl at week 96 in both arms without significant differences (intent-to-treat analyses). Thus, even if treatment is initiated early in asymptomatic patients with preserved CD4 counts, three drugs are necessary to achieve sustained decreases of HIV load in blood and lymphoid tissue.
    JAIDS Journal of Acquired Immune Deficiency Syndromes 01/2000; 23(1):17-25. · 4.43 Impact Factor
  • Article: A randomized trial of interferon-alpha2a and zidovudine versus bleomycin and zidovudine for AIDS-related Kaposi's sarcoma. Swiss HIV Cohort Study.
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    ABSTRACT: The efficacy and toxicity of interferon-alpha2a (9MU/d) and bleomycin (15 mg every 2 weeks), each combined with zidovudine (2x250 mg/d), was compared in a randomized study in 26 men with progressing AIDS-related Kaposi's sarcoma (KS). The median CD4 count was 113/microl. Complete or partial response was achieved in one (8%) of 12 evaluable patients on interferon and in 2 (20%) of 10 patients on bleomycin (P = 0.43) during 4.7 and 5.3 months of treatment, respectively. The tolerability was comparable. During extended follow up, survival time was 24 and 13 months in the interferon and bleomycin arm, respectively. In a multivariate Cox regression analysis, CD4 lymphocytes <200/microl (relative risk 3.74; 95% CI: 1.30-10.8) and randomization to interferon (relative risk 0.37; 95% CI: 0.15-0.90) were significantly predictive of mortality. New AIDS-related events occurred more frequently in patients who had received bleomycin. The antiviral activity of interferon-alpha or the chemotherapy-mediated increase in the risk for opportunistic infections may explain these differences.
    International Journal of STD & AIDS 06/1999; 10(6):369-75. · 1.09 Impact Factor
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    Article: Highly sensitive methods for quantitation of human immunodeficiency virus type 1 RNA from plasma, cells, and tissues.
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    ABSTRACT: Precise and sensitive quantitation of viral RNA in specimens from human immunodeficiency virus (HIV) type 1 (HIV-1)-infected individuals has become an indispensable tool for the monitoring of the efficacy of highly active antiretroviral combination therapy. The present report describes reproducible and efficient protocols with enhanced sensitivity for quantitation of HIV-1 RNA from plasma, peripheral blood mononuclear cells, and tissues with Qiagen silica columns for RNA purification combined with the Roche Amplicor HIV-1 Monitor test for quantitative reverse transcription-PCR (RT-PCR). Extraction of RNA from 0.5 ml of plasma resulted in the detection of fewer than 20 HIV RNA copies/ml of plasma, equivalent to the centrifugation-based boosted RT-PCR assay. Silica extraction of cellular RNA resulted in the detection of fewer than 3 HIV-1 RNA copies/microg of total RNA. These techniques facilitate direct comparisons of viral loads between liquid and cellular specimens. Application of these sensitive methods may improve the assessment of the response to new antiretroviral regimens.
    Journal of Clinical Microbiology 06/1999; 37(5):1260-4. · 4.15 Impact Factor
  • Article: [Chronic hepatitis B and C in HIV-infected patients].
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    ABSTRACT: This retrospective study examined the prevalence of co-infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) and the frequency of chronic hepatitis in HIV-infected patients with respect to both the different risk groups and the serological results. All Zurich participants of the Swiss HIV Cohort Study were evaluated who had available results of hepatitis B and C serology and ALT. Of the total 279 patients, 52% belonged to the intravenous drug user, 34% to the homosexual, and 11% to the heterosexual risk category. Serologically, previously acquired infection with HBV alone could be demonstrated in 92 (33%), HCV alone in 9 (3%), and both HBV and HCV in 130 (47%) patients. Only 3% of patients with sexually acquired HIV infection had anti-HCV antibodies, whereas co-infection with HBV and HCV was present in 87% of intravenous drug users. Among the 222 patients with previous HBV contact, 25 (11%) had positive HBsAg and 91 (41%) had "anti-HBc alone", both assumed to represent active HBV infection. 66 (24%) of 279 patients had chronic hepatitis with ALT elevation lasting > or = 6 months. Chronic hepatitis was present in 46% of those with active HBV and HCV co-infection, in 36% of those with HCV infection alone and in 18% of those with active HBV infection alone (P < 0.001). Of the 66 cases of chronic hepatitis, 58 were associated with HCV infection, and only 2 cases had no serological signs of active HBV or HCV infection. In patients with sexually acquired HIV infection, HBV had frequently been co-transmitted. In contrast, almost all of those infected by means of intravenous drug use had a co-infection with both HBV and HCV. The latter seems to play the strongest role in the development of chronic hepatitis with persistent ALT elevation. A chronic ALT elevation was almost always associated with serologically active HBV or HCV infection.
    DMW - Deutsche Medizinische Wochenschrift 06/1998; 123(24):753-60. · 0.53 Impact Factor
  • Article: Predictors of unprotected sexual contacts in HIV-infected persons in Switzerland.
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    ABSTRACT: Predictors of sexual risk behavior with regular and casual partners among HIV-infected heterosexual and gay persons were addressed. Sociodemographic data as well as self- and interviewer-reported data on sexual behavior were obtained from 117 asymptomatic HIV-infected persons enrolled in the Zurich part of the Swiss HIV Cohort Study (SHCS). Participants who reported sexual intercourse at least once (vaginal and/or anal) without condom use in the 6 months prior to interview were considered to have risk behavior. Sexual risk behavior was analyzed separately in contacts with regular and casual partners. In the 6-month preinterview period, 92% (108 of 117) of the HIV-infected study population reported sexual contacts, and 30/117 (26%) had at least one unprotected vaginal and/or anal contact. Among 93 persons using condoms, 25% of the heterosexual and 10% of the homosexual participants reported breakage of the condom. The main predictor for unprotected sexual behavior with regular partners was an elevated number of contacts. Predictors for sexual risk behavior with casual partners were the combination of alcohol and sexual encounters and the change of sexual behavior since the epidemic of AIDS. These findings did not differ between persons with hetero- and homosexual behavior. Considering that these contacts may have passed the virus on to the seronegative population, that the probability of unsafe sex increased with the growing number of contacts, and that the number of condom breakages was remarkable, it is imperative that this group be educated and motivated to take the active role in insisting on safer sex practices in each encounter.
    Archives of Sexual Behavior 03/1998; 27(1):77-90. · 3.53 Impact Factor
  • Article: Frequent chronic hepatitis B virus infection in HIV-infected patients positive for antibody to hepatitis B core antigen only. Swiss HIV Cohort Study.
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    ABSTRACT: Persons with immune deficiency may present with atypical results in serological tests for hepatitis B virus (HBV). Frozen serum specimens that were sequentially obtained over time from a cohort of 57 HIV-infected patients, all of whom tested positive only for antibody to hepatitis B core antigen (anti-HBcAg), were therefore retested for HBV markers, including HBV DNA. The results were assessed for their time course and correlated with clinical data and alanine aminotransferase (ALT) values. Forty-eight patients were male; intravenous drug users constituted the principal risk group (n = 30), followed by homosexual men (n = 22). Thirty-three persons tested positive for antibody to hepatitis C virus (anti-HCV). During a median of 31 months from the first to the last serum, anti-HBcAg remained the sole marker of HBV infection in 98.2% of the patients. Polymerase chain reaction (PCR) to detect DNA for HBV core and HBV surface gene was positive in 126 (62.4%) and 121 (59.9%) of all 202 serum samples, respectively. Over time, HBV DNA was detected at least once in 51 (89.5%) patients. In contrast, decomplexed hepatitis B surface antigen (HBsAg) was detected at least once in 14 (24.6%) patients. Among patients positive for HBV DNA and negative for anti-HCV, eight (36.4%) of 22 had chronic hepatitis (ALT elevation > or = 6 months) that was attributable only to persisting HBV infection. Similarly, 12 (41.4%) of 29 patients positive for both HBV DNA and anti-HCV had chronic viral hepatitis, but their ALT values were significantly higher. In HIV-infected patients, anti-HBcAg as the sole serological HBV marker detected must be considered indicative of chronic HBV infection and is in part associated with chronic hepatitis and ALT elevation.
    European Journal of Clinical Microbiology 01/1998; 17(1):6-13. · 2.86 Impact Factor
  • Article: Improvement in immune function due to treatment with indinavir despite severe immune deficiency.
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    ABSTRACT: To study the virological, immunological and clinical effects of the protease inhibitor indinavir in human immunodeficiency virus (HIV)-infected patients with CD4 counts < 50 cells/mm3, indinavir was added to prior treatment with nucleoside analogues in a prospective open-label study in 23 HIV-infected patients with median CD4 count of 10 cells/mm3 and median serum HIV-1 RNA load of 27,508 copies/ml. Addition of indinavir induced a decrease in HIV-1 RNA levels to < 400 copies/ml in 15 patients that was maintained until week 36 of the study in 8 (35%) patients. The median increase in CD4 cell counts was 92 cells/mm3 (range 55-258 cells/mm3) and in CD8 counts was 245 cells/mm3 (range 51-1552 cells/mm3) at week 30. The treatment induced a significant CD8 T cell expansion, consisting in the first 6 weeks of predominantly memory CD45RO+ cells and followed by expansion of naive cells from week 12 on, and a significant decrease in the proportion of activated CD8/CD38 cells. In addition, significant increases in T cell proliferation following stimulation with phytohaemagglutinin and significant decreases in the rates of spontaneous apoptosis of CD4+ and CD8+ T cells were observed. In conclusion, the addition of indinavir induced restoration of both memory and naive CD8 T cells. Corresponding evidence of improving T cell function, as assessed by enhanced lymphoproliferative capacity and diminished propensity to undergo apoptosis, provides evidence for treatment-induced regeneration of immune function even in patients with severe immunodeficiency.
    Antiviral therapy 01/1998; 3(3):159-67. · 3.16 Impact Factor
  • Article: Are immunological markers, social and personal resources, or a complaint-free state predictors of progression among HIV-infected patients?
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    ABSTRACT: Predictors of disease progression were studied in 89 asymptomatic HIV-infected patients who were prospectively evaluated for psychosocial variables and the development of clinical symptoms over a period of 2 years. The subjects were assessed for symptoms, laboratory measures, demographic variables, social and personal resources, mental status, alcohol, nicotine and drug use, sexual activity and risk behaviour, and sexually transmitted diseases. After 1 year, 17% of the patients had developed HIV-associated symptoms (symptomatic disease or AIDS), and after 2 years, 32% had developed symptoms or had died. In the multivariate analyses, the baseline CD4 count was the only significant predictor of disease progression during both observation periods. Psychosocial measures did not predict the progression of HIV infection.
    Acta Psychiatrica Scandinavica 07/1997; 95(6):476-84. · 4.22 Impact Factor
  • Article: Simple monitoring of antiretroviral therapy with a signal-amplification-boosted HIV-1 p24 antigen assay with heat-denatured plasma.
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    ABSTRACT: Virus load determination has become indispensable for the management of HIV patients, but depends on expensive assays of a low throughput. We evaluated whether a highly improved HIV-1 p24 antigen detection procedure which involves heat-mediated immune complex dissociation and signal-amplification-boosted enzyme-linked immunosorbent assay (ELISA) was suitable for antiretroviral treatment monitoring. Virus load in plasma was determined for 127 plasma samples taken at 0, 2, 6, 12, 18, 24, 30 and 36 weeks from 23 patients with CD4+ T cells < 50 x 10(6)/l who received indinavir 800 mg three times daily in addition to prior antiretroviral treatment. Tests included polymerase chain reaction (PCR) for viral RNA, measured prospectively with the Roche Amplicor kit, and retrospective batch testing of heat-denatured samples for p24 antigen by the DuPont HIV-1 p24 Core Profile ELISA linked with a tyramide signal amplification step. Particle-associated reverse transcriptase (RT) by the product-enhanced RT (PERT) assay was determined as an independent third-opinion viral load marker. p24 antigen was detected as sensitively as viral RNA. Overall detection during a median observation time of 25 weeks (range, 0-39) amounted to 75.6% for antigen and 73.6% for RNA. The antigen detection limit was 0.2 pg/ml. Antigen was detectable in all 23 baseline samples, whereas RNA was undetectable in one. Antigen and RNA levels in 79 samples positive for both markers correlated with r = 0.714 (P < 0.0001). Average changes in levels of p24 antigen and RNA at eight timepoints correlated with r = 0.982 (P < 0.0001). In individual patients, the two parameters behaved similarly, and in certain cases virtually identically. RT activity was measurable in all samples. The performance of this antigen detection procedure is comparable to RNA PCR, thus providing a simple, high throughput alternative in monitoring the efficacy of antiretroviral treatment.
    AIDS 06/1997; 11(6):F47-52. · 6.24 Impact Factor
  • Article: Cerebral microsporidiosis due to Encephalitozoon cuniculi in a patient with human immunodeficiency virus infection.
    New England Journal of Medicine 03/1997; 336(7):474-8. · 53.30 Impact Factor
  • Article: HIV-associated primary pulmonary hypertension. A case control study. Swiss HIV Cohort Study.
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    ABSTRACT: To assess the clinical and echocardiographic time course, prognosis, and possible etiology of HIV-associated primary pulmonary hypertension (PPH), we prospectively followed all 19 patients in whom PPH was diagnosed in our centers. Women (12 cases) and injecting drug use (16 cases) predominated; the median CD4 lymphocytes count was 83/microliter (range, 1 to 740). Matched control subjects without PPH were identified within the Swiss HIV Cohort Study. Frozen serum samples of both groups were then reanalyzed for autoimmune parameters, neopterin, beta-2-microglobulin, and thyroid-stimulating hormone. The median follow up of the patients was 1.3 yr. Follow-up Doppler echocardiography was available in 13 patients. The RVSP-RAP pressure gradient decreased by 3.2 mm Hg for those six patients who received antiretroviral treatment but increased by 19.0 mm Hg for untreated patients (p = 0.026). PPH was the cause of eight of 17 deaths. The probability of surviving was significantly decreased in patients with PPH in comparison with the control subjects; the median survival was 1.3 versus 2.6 yr (p < 0.05). Patients with PPH had significantly higher anticardiolipin IgM, anti SS-B, and neopterin, but all other laboratory values did not differ between cases and control subjects. In conclusion, HIV-associated PPH contributed significantly to mortality. Antiretroviral treatment may exert a beneficial effect on the pressure gradient. A possible role of an autoimmune phenomenon in the pathogenesis could not be substantiated.
    American Journal of Respiratory and Critical Care Medicine 03/1997; 155(3):990-5. · 11.08 Impact Factor
  • Article: Condom breakage and prevention of HIV transmission: an underestimated problem.
    International Journal of STD & AIDS 02/1997; 8(1):69-70. · 1.09 Impact Factor
  • Article: [Cervical lymphadenitis in an immunocompetent patient: Mycobacterium gordonae as the cause?].
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    ABSTRACT: A 76-year-old man went to an ENT outpatient clinic because of stabbing pain in the left throat and difficult swallowing. He was found to have tonsillitis on the left and cervical lymphadenitis. The symptoms regressed on treatment with amoxycillin and clavulanic acid, but the cervical lymphadenitis persisted. Fine-needle biopsy of the cervical swelling was not diagnostic. Computed tomography of the neck showed an encapsulated liquid space-occupying lesion with infiltration of surrounding soft tissues. The cervical lymph-node mass was excised and histologically found to contain epithelioid granulomas with a few giant cells and scattered centrally caseous necroses. Tuberculostatic treatment was started; drainage fluid from the wound grew acid-fast bacilli, identified by gene probe as Mycobacterium gordonae. Mycobacterium gordonae is ubiquitous in the environment and is being identified ever more frequently in microbiological laboratories, usually as contaminant. It rarely causes infections of soft tissues and the lungs or systemically.
    DMW - Deutsche Medizinische Wochenschrift 02/1997; 122(3):51-3. · 0.53 Impact Factor
  • Article: [Mycobacterium haemophilum infection in a patient with AIDS].
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    ABSTRACT: A 35-year-old HIV-infected man with a CD4 cell count of 100/microliter who had returned from a holiday in Spain presented with fever, chronic diarrhoea, cough, oral ulcers, subcutaneous nodules of about 1 cm in diameter and crusted skin ulcers of about 2 cm in diameter at his right arm, both wrists and buttocks. Microscopic examination and culture of smears of a skin ulcer revealed acid-fast bacteria. Mycobacterial cultures of blood, sputum, urine and stool remained sterile. Before the microorganisms were identified culturally, atypical mycobacteriosis was assumed and treatment with rifampicin, ethambutol, isoniazid and clarithromycin was started. Mycobacterium haemophilum was identified by using molecular biological techniques. Within 3 weeks the patient became afebrile and the skin ulcers healed completely. After a 7-week course, the treatment had to be stopped, and one month later painful subcutaneous nodules developed again at his arms and legs. A relapse of Mycobacterium haemophilum infection was confirmed by culture of a fine needle aspirate of a nodule. The same treatment was restarted and the nodules disappeared. Mycobacterium haemophilum, first identified in 1978, is an emerging pathogen in immunocompromised patients. Clinical manifestations usually are skin ulcers, subcutaneous nodules and subcutaneous abscesses, and less frequently, systemic infection. Treatment options of this life threatening disease have yet to be defined but therapeutic response to tuberculostatic combination therapy has been observed. Since Mycobacterium haemophilum is a fastidious organism, special laboratory methods are required for cultivation as well as for identification.
    DMW - Deutsche Medizinische Wochenschrift 10/1996; 121(39):1189-92. · 0.53 Impact Factor
  • Article: Heat-mediated immune complex dissociation and enzyme-linked immunosorbent assay signal amplification render p24 antigen detection in plasma as sensitive as HIV-1 RNA detection by polymerase chain reaction.
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    ABSTRACT: To compare heat denaturation and acidification as immune complex dissociation (ICD) methods in adult HIV-1 infection and to increase the sensitivity by a signal-amplification-boosted HIV-1 p24 antigen enzyme-linked immunosorbent assay (ELISA). Prospective and retrospective blinded study of paired serum and plasma samples from 245 patients (112 of class A, 66 of B, 67 of C of the Centers for Disease Control and Prevention 1993 classification). Plasma and sera were prospectively tested for antigen by ELISA using native, acidified, or heat-denatured material. Retrospective tests included batch analysis of heat-denatured samples for antigen by the signal-amplification-boosted ELISA and for viral RNA. With serum, native antigen was reactive in 26.5%. Acidification increased the rate to 53.1% (P < or = 0.0001), but was inefficient at a CD4+ count > or = 500 x 10(6)/l. Heat denaturation further elevated the rate to 67.8% (P < or = 0.0007) and the use of plasma to 78.0% (P < or = 0.008). The boosted ELISA, performed with plasma samples diluted 1 :6, which eliminated the problem of heat-induced sample coagulation, was confirmed positive in 89.5% of serum and 97.8% of plasma samples. RNA was detected in 95.7%. Heat-mediated ICD combined with a signal-amplification-boosted ELISA detects HIV-1 expression as sensitively as a polymerase chain reaction kit for viral RNA, but at only a fraction of the cost. The procedure uses a 50 microliters plasma sample and should be fully automatable.
    AIDS 10/1996; 10(10):1085-90. · 6.24 Impact Factor
  • Article: Does dapsone increase mortality when given for prophylaxis of Pneumocystis carinii pneumonia?
    M Opravil, B Hirschel, R Lüthy
    AIDS 09/1996; 10(9):1045-6. · 6.24 Impact Factor
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    Article: Monitoring of co-trimoxazole concentrations in serum during treatment of pneumocystis carinii pneumonia.
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    ABSTRACT: The purpose of this prospective randomized open trial was to investigate the impact of monitoring concentrations in serum on the efficacy and side effects of high-dose co-trimoxazole therapy. Forty consecutive patients with microscopically confirmed Pneumocystis carinii pneumonia were enrolled. Therapy was started with 5 and 25 mg of trimethoprim and sulfamethoxazole, respectively, per kg of body weight given every 6 h for 2 days and continued every 8 h either with (group A) or without (group B) monitoring and dose adjustments according to sulfamethoxazole levels in serum (target, 150 to 200 micrograms/ml) for a total of 21 days. Only 7 of 19 patients (83%). Patients who were treated for the full period and patients for whom co-trimoxazole was prematurely stopped had similar concentrations of sulfamethoxazole (157 +/- 52 versus 155 +/- 47 micrograms/ml) and trimethoprim (5.0 +/- 1.4 versus 5.6 +/- 1.0 microgram/ml). Concentrations of sulfamethoxazole and trimethoprim in group A (158 +/- 39 and 5.6 +/- 1.8 micrograms/ml, respectively) did not differ from those in group B (153 +/- 57 and 5.1 +/- 1.6 micrograms/ml, respectively), and the average daily maintenance doses for groups A (75.4 mg/kg plus 15.1 mg/kg) and B (76.4 mg/kg plus 15.3 mg/kg) were nearly identical. Although the average sulfamethoxazole concentrations were maintained within the target zone in the monitoring group (day 5, 160 +/- 44 micrograms/ml; day 10, 160 +/- 41 micrograms/ml; day 15, 168 +/- micrograms/ml; and day 21, 157 +/- 95 micrograms/ml), only 28% of the individual sulfamethoxazole levels were within the target range of 150 to 200 micrograms/ml after the dose adjustments (32% in group B without intervention). Response rates were similar in both groups. Complete response or improvement was observed in 18 of 19 (group A) and 19 of 21 (group B) patients. The method used for monitoring sulfamethoxazole levels with subsequent dose adjustment did not allow us to reliably achieve the target concentrations and did not significantly alter the incidence of side effects or the efficacy of the therapy.
    Antimicrobial Agents and Chemotherapy 01/1996; 39(12):2661-6. · 4.84 Impact Factor
  • Article: Nephrotoxicity, high frequency ototoxicity, efficacy and serum kinetics of once versus thrice daily dosing of netilmicin in patients with serious infections.
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    ABSTRACT: The effect of dosing regimen on nephrotoxicity, high frequency ototoxicity, efficacy and serum kinetics was studied in a prospective, randomised clinical study. Therapy was started with total daily doses of 6 mg/kg given once (od) or thrice (tid) daily to 56 and 57 patients, respectively. Subsequent doses were adjusted according to serum levels. No major differences in toxicity or efficacy were noticed between od and tid regimens: clinical failures occurred in two and two patients, four and five patients suffered from a decrease of > or = 20 dB at least unilaterally at one frequency between 8 and 18 kHz, six and seven patients had a > 25 mumol/L or > 25% increase in serum creatinine, respectively. Serum creatinine or creatinine clearance did not change significantly during either therapy. Major differences between the two study groups were limited to pharmacokinetic parameters. Od dosing resulted in higher peak (mean of 21.6 vs 7.2 mg/L) and lower trough levels (0.5 vs 1.4 mg/L). Half-lives of netilmicin determined between 1 and 8 h increased significantly during therapy with tid (from a mean of 2.75 to a mean of 3.33 h, P < 0.01) but not significantly with od (rise from 2.8 to 3.03 h). Much longer half-lives were determined between 8 and 24 h in the od group (mean of 5.7 h, P < 0.01). In conclusion, only minimal differences in toxicity and efficacy were observed. Their clinical relevance appears to be minimal.
    Journal of Antimicrobial Chemotherapy 12/1995; 36(5):803-14. · 5.07 Impact Factor