RESUMO
Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.
Assuntos
Dióxido de Carbono/análise , Sequestro de Carbono , Floresta Úmida , Atmosfera/química , Biomassa , Brasil , Carbono/análise , Carbono/metabolismo , Dióxido de Carbono/metabolismo , Caules de Planta/metabolismo , Árvores/crescimento & desenvolvimento , Árvores/metabolismo , Clima Tropical , Madeira/análiseRESUMO
Most countries exclude human immunodeficiency virus (HIV)-positive patients from organ donation because of concerns regarding donor-derived HIV transmission. The Swiss Federal Act on Transplantation has allowed organ transplantation between HIV-positive donors and recipients since 2007. We report the successful liver transplantation from an HIV-positive donor to an HIV-positive recipient. Both donor and recipient had been treated for many years with antiretroviral therapy and harbored multidrug-resistant viruses. Five months after transplantation, HIV viremia remains undetectable. This observation supports the inclusion of appropriate HIV-positive donors for transplants specifically allocated to HIV-positive recipients.
Assuntos
Sobrevivência de Enxerto/imunologia , Infecções por HIV/cirurgia , Soropositividade para HIV , HIV-1/imunologia , Transplante de Fígado , Doadores de Tecidos/provisão & distribuição , Obtenção de Tecidos e Órgãos , Idoso , Infecções por HIV/virologia , Humanos , Masculino , Pessoa de Meia-Idade , PrognósticoRESUMO
Ecosystems across the globe are threatened by climate change and human activities. New rapid survey approaches for monitoring biodiversity would greatly advance assessment and understanding of these threats. Taking advantage of next-generation DNA sequencing, we tested an approach we call metabarcoding: high-throughput and simultaneous taxa identification based on a very short (usually <100 base pairs) but informative DNA fragment. Short DNA fragments allow the use of degraded DNA from environmental samples. All analyses included amplification using plant-specific versatile primers, sequencing and estimation of taxonomic diversity. We tested in three steps whether degraded DNA from dead material in soil has the potential of efficiently assessing biodiversity in different biomes. First, soil DNA from eight boreal plant communities located in two different vegetation types (meadow and heath) was amplified. Plant diversity detected from boreal soil was highly consistent with plant taxonomic and growth form diversity estimated from conventional above-ground surveys. Second, we assessed DNA persistence using samples from formerly cultivated soils in temperate environments. We found that the number of crop DNA sequences retrieved strongly varied with years since last cultivation, and crop sequences were absent from nearby, uncultivated plots. Third, we assessed the universal applicability of DNA metabarcoding using soil samples from tropical environments: a large proportion of species and families from the study site were efficiently recovered. The results open unprecedented opportunities for large-scale DNA-based biodiversity studies across a range of taxonomic groups using standardized metabarcoding approaches.
Assuntos
Biodiversidade , DNA de Plantas/análise , Plantas/classificação , Solo/análise , Clima , Código de Barras de DNA Taxonômico , Desenvolvimento Vegetal , Plantas/genéticaRESUMO
BACKGROUND: In Switzerland each year, influenza leads to between 112,000 and 275,000 medical consultations. Data on nosocomial influenza infection are limited. AIM: To describe nosocomial cases of seasonal influenza in south-western Switzerland. METHODS: This study was conducted during two seasonal influenza epidemics from 2016 to 2018 in 27 acute care public hospitals in south-western Switzerland. During these two time-periods, every patient hospitalized for >72 h who was positively screened by reverse transcription-polymerase chain reaction or antigen detection for influenza was included in the survey. Characteristics of patients included age, sex, and comorbidities. Included patients were followed up until discharge or death. Complications and administration of antineuraminidases and/or antibiotics were registered. FINDINGS: The median influenza vaccine coverage of healthcare workers was 40%. In all, 836 patients were included (98% with type A influenza virus in 2016-2017; 77% with type B virus in 2017-2018). Most patients (81%) had an unknown vaccine status. Overall, the incidence of nosocomial influenza was 0.5 per 100 admissions (0.35 per 1000 patient-days). The most frequent comorbidities were diabetes (20%), chronic respiratory diseases (19%), and malnutrition (17%). Fever (77%) and cough (66%) were the most frequent symptoms. Seventy-one percent of patients received antineuraminidases, 28% received antibiotics. Infectious complications such as pneumonia were reported in 9%. Overall, the all-cause mortality was 6%. CONCLUSION: The occurrence of nosocomial influenza underlines the importance of vaccinating patients and healthcare workers, rapidly recognizing community- or hospital-acquired cases, and applying adequate additional measures to prevent dissemination, including the timely administration of antineuraminidases to avoid antibiotic use (and misuse).
Assuntos
Infecção Hospitalar , Epidemias , Influenza Humana , Infecção Hospitalar/epidemiologia , Hospitais , Humanos , Influenza Humana/epidemiologia , Estações do Ano , Suíça/epidemiologiaRESUMO
Background The principal causes of liver enzyme elevation among HIV-hepatitis B virus (HBV) co-infected patients are the hepatotoxic effects of antiretroviral therapy (ART), alcohol abuse, ART-induced immune reconstitution and the exacerbation of chronic HBV infection. Objectives To investigate the incidence and severity of liver enzyme elevation, liver failure and death following lamivudine (3TC) withdrawal in HIV-HBV co-infected patients. Methods Retrospective analysis of the Swiss HIV Cohort Study database to assess the clinical and biological consequences of the discontinuation of 3TC. Variables considered for analysis included liver enzyme, HIV virological and immunological parameters, and medication prescribed during a 6-month period following 3TC withdrawal. Results 3TC was discontinued in 255 patients on 363 occasions. On 147 occasions (109 patients), a follow-up visit within 6 months following 3TC withdrawal was recorded. Among these patients, liver enzyme elevation occurred on 42 occasions (29%), three of them (2%) with severity grade III and five of them (3.4%) with severity grade IV elevations (as defined by the AIDS Clinical Trials Group). Three patients presented with fulminant hepatitis. One death (0.7%) was recorded. Conclusions HBV reactivation leading to liver dysfunction may be an under-reported consequence of 3TC withdrawal in HIV-HBV co-infected patients. Regular monitoring of HBV markers is warranted if active therapy against HBV is discontinued.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/complicações , Fármacos Anti-HIV/uso terapêutico , HIV-1 , Hepatite B/complicações , Lamivudina/uso terapêutico , Hepatopatias/etiologia , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Adulto , Terapia Antirretroviral de Alta Atividade , Contagem de Linfócito CD4 , Métodos Epidemiológicos , Feminino , Hepatite B/tratamento farmacológico , Antígenos E da Hepatite B/efeitos dos fármacos , Humanos , Hepatopatias/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Recidiva , Suíça , Carga ViralRESUMO
Several upcoming satellite missions have core science requirements to produce data for accurate forest aboveground biomass mapping. Largely because of these mission datasets, the number of available biomass products is expected to greatly increase over the coming decade. Despite the recognized importance of biomass mapping for a wide range of science, policy and management applications, there remains no community accepted standard for satellite-based biomass map validation. The Committee on Earth Observing Satellites (CEOS) is developing a protocol to fill this need in advance of the next generation of biomass-relevant satellites, and this paper presents a review of biomass validation practices from a CEOS perspective. We outline the wide range of anticipated user requirements for product accuracy assessment and provide recommendations for the validation of biomass products. These recommendations include the collection of new, high-quality in situ data and the use of airborne lidar biomass maps as tools toward transparent multi-resolution validation. Adoption of community-vetted validation standards and practices will facilitate the uptake of the next generation of biomass products.
RESUMO
Discontinuation of maintenance therapy against toxoplasma encephalitis (TE) for individuals infected with human immunodeficiency virus (HIV) who are receiving successful anti-retroviral therapy is considered safe. Nevertheless, there are few published studies concerning this issue. Within the setting of the Swiss HIV Cohort Study, this report describes a prospective study of discontinuation of maintenance therapy against TE in patients with a sustained increase of CD4 counts to > 200 cells/microL and 14% of total lymphocytes, and no active lesions on cerebral magnetic resonance imaging (MRI). In addition to clinical evaluation, cerebral MRI was performed at baseline, and 1 and 6 months following discontinuation. Twenty-six AIDS patients with a history of TE agreed to participate, but three patients (11%) could not be enrolled because they still showed enhancing cerebral lesions without a clinical correlate. One patient refused MRI after 6 months while clinically asymptomatic. Among the remaining 22 patients who discontinued maintenance therapy, one relapsed after 3 months. During a total follow-up of 58 patient-years, there was no TE relapse among the patients who had remained clinically and radiologically free of relapse during the study. Thus, discontinuation of maintenance therapy against TE was generally safe, but may fail in a minority of patients. Patients who remain clinically and radiologically free of relapse at 6 months after discontinuation are unlikely to experience a relapse of TE.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Antirretrovirais/uso terapêutico , Antiprotozoários/administração & dosagem , Toxoplasmose Cerebral/tratamento farmacológico , Adulto , Animais , Contagem de Linfócito CD4 , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Suíça , Resultado do Tratamento , Carga ViralRESUMO
Current evidence no longer justifies the introduction of antiretroviral treatment during primary HIV infection. Consequently, patients presenting with the acute retroviral syndrome should not be treated outside clinical studies. For patients with chronic infection, the decline of opportunistic infections, due to the efficacy of highly active antiretroviral therapy, has left the place to daily problems of adverse effects and drug interactions. In Switzerland, the follow-up of HIV-infected adults is organized within the framework of a prospective cohort study.
Assuntos
Infecções por HIV/tratamento farmacológico , Doença Aguda , Progressão da Doença , Seguimentos , Humanos , Masculino , Estudos Prospectivos , SíndromeRESUMO
OBJECTIVES: To characterize clinical and epidemiologic features of infections with Mycobacterium genavense. DESIGN: Case series and case-control studies. Patients with M genavense were compared with two control groups: CD4 controls were matched on the basis of CD4 counts, and Mycobacterium avium-intracellulare complex controls had disseminated infection with M avium-intracellulare complex. RESULTS: Fifty-four patients with disseminated infections caused by M genavense were found, from Europe (37), North America (15), and Australia (two). All were infected with human immunodeficiency virus. The median CD4 count was 0.016 x 10(9)/L (16/mm3) (range, 0.001 to 0.082 x 10(9)/L). Eighty-seven percent had fever and weight loss, 44% had diarrhea, 43% had splenomegaly, 39% had hepatomegaly, and 72% had anemia. In Swiss university hospitals, M genavense was responsible for 12.8% of nontuberculous disseminated mycobacterial infections in patients with human immunodeficiency virus from 1990 to 1992. The median survival was 190 days after the first isolation of M genavense. Among the patients who had been treated with at least two antimycobacterial drugs for 1 month or more, median survival was 263 days (95% confidence interval, 144 to 382 days), compared with 81 days (95% confidence interval, 73 to 89 days) for those not treated (P = .0009). Survival in patients with M genavense was similar to the survival of M avium-intracellulare complex controls. However, patients with similar CD4 counts (CD4 controls) survived longer (median, 342 days; 95% confidence interval, 269 to 415 days; P < .0003). CONCLUSIONS: Infection with M genavense may be responsible for more than 10% of disseminated nontuberculous mycobacterial infections in patients with human immunodeficiency virus infection. Its clinical presentation and response to treatment are similar to those of infection with M avium-intracellulare complex.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Infecções por Mycobacterium não Tuberculosas/diagnóstico , Infecções por Mycobacterium não Tuberculosas/epidemiologia , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Adolescente , Adulto , Austrália/epidemiologia , Contagem de Linfócito CD4 , Estudos de Casos e Controles , Criança , Europa (Continente)/epidemiologia , Feminino , Humanos , Tábuas de Vida , Masculino , Pessoa de Meia-Idade , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Complexo Mycobacterium avium , Infecção por Mycobacterium avium-intracellulare/epidemiologia , América do Norte/epidemiologia , Taxa de SobrevidaRESUMO
Five renal transplant recipients developed Pneumocystis carinii pneumonia (PCP) over a 22-month period, while no cases had been observed over a 5-year period in 114 transplanted patients treated with the same immunosuppressive protocol. All patients were HIV-negative, and no modification in diagnostic techniques for P. carinii could account for this observation. All five patients developed PCP within 2 months of an acute graft rejection episode. All of them attended the same outpatient facility as AIDS patients attending the hospital, where they shared the waiting and treatment rooms. Comparison of cases with matched controls was possible in three instances and revealed that the cases had had more outpatient clinic encounters with AIDS patients who had presented, or subsequently developed, PCP. This observation suggests that AIDS patients developing PCP may transmit the infection to other immunosuppressed patients.
Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , Transplante de Rim/efeitos adversos , Infecções Oportunistas/transmissão , Pneumonia por Pneumocystis/transmissão , Adulto , Estudos de Casos e Controles , Análise por Conglomerados , Feminino , Humanos , Terapia de Imunossupressão/efeitos adversos , Transplante de Rim/imunologia , Masculino , Pessoa de Meia-Idade , Infecções Oportunistas/complicações , Infecções Oportunistas/epidemiologia , Pneumonia por Pneumocystis/complicações , Pneumonia por Pneumocystis/epidemiologia , Suíça/epidemiologiaRESUMO
OBJECTIVE: Lipid disorders associated with the use of protease inhibitors may contribute to the premature development of atherosclerosis. The purpose of the present study was to determine whether the administration of a protease inhibitor-containing regimen to middle-aged (30-50 years) HIV-infected individuals for 6 months or longer is associated with an increased prevalence of atherosclerosis. METHODS: High-resolution B-mode ultrasound imaging was used to visualize the femoral and carotid arteries of 68 HIV-negative and 168 HIV-infected individuals, including 136 patients who had received protease inhibitors for 26.8 +/- 8.9 months (mean +/- SD). Atherogenic plaques were defined as a thickening of the intima-media > or = 1200 mm. RESULTS: The proportion of participants with one or more plaques was higher in the HIV-infected group in comparison with the HIV-negative group (55 versus 38%; P = 0.02), and so was the prevalence of cigarette smoking (61 versus 46%; P = 0.03) and hyperlipidaemia (56 versus 24%; P < 0.001). The presence of plaque was independently associated with age, male gender, plasma low-density lipoprotein cholesterol levels and smoking. In univariate logistic regression analysis, an association was also found with HIV infection. Among HIV-infected subjects protease inhibitor therapy was not associated with the presence of plaque. CONCLUSIONS: A large proportion of the middle-aged HIV-infected individuals examined during this study had one or more atherosclerotic plaques within the femoral or carotid arteries. The presence of peripheral atherosclerosis within this population is not associated with the use of protease inhibitors, but rather with 'classic' cardiovascular risk factors such as smoking and hyperlipidaemia, which are amenable to interventions.
Assuntos
Arteriosclerose/etiologia , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Inibidores da Protease de HIV/efeitos adversos , Adulto , Fatores Etários , Arteriosclerose/induzido quimicamente , Arteriosclerose/epidemiologia , Artérias Carótidas/diagnóstico por imagem , Estenose das Carótidas/diagnóstico por imagem , Colesterol/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Feminino , Artéria Femoral/diagnóstico por imagem , Soronegatividade para HIV , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Fumar , Triglicerídeos/sangue , UltrassonografiaRESUMO
OBJECTIVE: The current recommendation that patients infected with HIV-1 be treated early is based on little evidence. We examined whether the early initiation of antiretroviral treatment affects residual HIV-1 viraemia. METHODS: Viraemia was measured using an assay with a detection limit of 3 HIV-1 RNA copies/ml in drug-naive patients who started antiretroviral therapy at the time of primary HIV-1 infection (PHI) (n = 10), during chronic infection without immune suppression (CD4 cell counts > or = 500/mm3; median 577) (n = 10), or after immune suppression developed (CD4 cell counts < 500/mm3; median 113) (n = 21). RESULTS: In 249 samples collected 24 to 120 weeks after treatment initiation, the mean proportion of samples with HIV-1 RNA levels of less than 3 copies/ml was 75% for PHI patients compared with 32 and 8% for immunocompetent and immunosuppressed chronically infected patients, respectively. Fifty per cent of PHI patients, but none of the chronically infected patients, had persistently fewer than 3 HIV-1 RNA copies/mL. PHI patients had lower residual HIV-1 RNA levels than chronically infected patients, and immunocompetent patients had lower residual HIV-1 RNA levels than immunosuppressed patients (all pairwise, P< 0.001). The mean residual HIV-1 RNA level was independently associated with the initiation of therapy during PHI and baseline CD4 cell counts (P < 0.001 for both associations). CONCLUSION: Viraemia levels are associated with clinical progression and predict virological treatment failure. The initiation of antiretroviral therapy at the time of PHI and while CD4 cell counts are high results in lower residual viraemia. These results support early antiretroviral therapy in HIV-1-infected patients.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , HIV-1/isolamento & purificação , RNA Viral/sangue , Fármacos Anti-HIV/administração & dosagem , Contagem de Linfócito CD4 , Estudos de Coortes , Infecções por HIV/virologia , Humanos , Sensibilidade e Especificidade , Carga ViralRESUMO
OBJECTIVE: To assess the prognostic significance of drug-associated mutations in the protease and reverse transcriptase (RT) genes on virological response to salvage therapy. PATIENTS: All patients from four centres of the Swiss HIV Cohort Study who were switched, between February and October 1997, to nelfinavir plus other antiretroviral drugs following failure of highly active antiretroviral therapy (HIV-1 RNA >1000 copies/ml after > 3 months). METHODS: Direct sequencing of RT and protease genes derived from plasma RNA was performed in 62 patients before salvage therapy. Baseline predictors (drug-resistance mutations, drug exposure, clinical and biological parameters) of virological response after 4-12 weeks of therapy were assessed by linear regression analyses. RESULTS: Patients had been treated with RT inhibitors and protease inhibitors for a median duration of 35.6 and 12.2 months, respectively. Baseline median CD4 cell count was 113 x 10(6)/l and HIV-1 RNA 5.16 log10 copies/ml. The median decrease of HIV-1 RNA was 0.38 log10; 32% of the patients showed > 1 log10 decrease. At baseline, 90% of the patients had RT inhibitor-resistance mutations with a median number per patient of four (range, 0-7). Primary and secondary protease inhibitor-resistance mutations were detected in 69% and 89% of the patients, respectively. The median number of total protease inhibitor-resistance mutations per patient was four (range, 0-9). In univariate analysis, virological response to salvage therapy was associated with number of RT inhibitors, primary and secondary protease inhibitor-resistance mutations, history of protease inhibitor use (duration and number), but not with clinical stage, HIV-1 RNA level or CD4 cell count. After adjustment for all variables, the number of RT inhibitor plus protease inhibitor-resistance mutations was the only independent predictor. CONCLUSIONS: In patients with advanced HIV infection, the virological response to salvage therapy containing nelfinavir is best predicted by the number of baseline RT inhibitor plus protease inhibitor-resistance mutations.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , Inibidores da Protease de HIV/uso terapêutico , Protease de HIV/genética , Transcriptase Reversa do HIV/genética , HIV-1/genética , Mutação , Inibidores da Transcriptase Reversa/uso terapêutico , Terapia de Salvação , Didesoxinucleosídeos/uso terapêutico , Resistência Microbiana a Medicamentos/genética , Feminino , Genótipo , HIV-1/efeitos dos fármacos , Humanos , Masculino , Valor Preditivo dos Testes , Terapia de Salvação/métodosRESUMO
OBJECTIVE: To assess the impact of primary HIV infection (PHI) on the spread of HIV and the temporal trends in transmission of HIV drug resistance between 1996 and 1999 in Switzerland. METHODS: Sequencing of the genes for reverse transcriptase (RT) and protease was performed for 197 individuals with documented PHI. Phylogenetic analyses were confronted with epidemiological data. RESULTS: Significant clustering was demonstrated for 29% of the RT sequences. All these cases occurred closely together in place and time; contact tracing demonstrated transmission at the time of PHI in 30% of them. Genotypic drug resistance was detected in 8.6% of PHI individuals in 1996, 14.6% in 1997, 8.8% in 1998 and 5.0% in 1999. Drug-resistant variants were identified in 11.3% of individuals infected by homosexual contacts, 6.1% by heterosexual contacts, 13% of intravenous drug users and more frequently in men (10.4%) than women (2.6%). Potential factors involved in the recent decrease of transmission of drug-resistant variants include increase of HIV non-B subtypes from 23% in 1996 to 35% in 1999 (only one non-B subtype had resistance mutations) and a steady increase of patients with undetectable viraemia as documented in Swiss HIV Cohort Study (10% in 1996 vs 53% in 1999). CONCLUSIONS: Phylogenetic and epidemiological analyses underline the impact of PHI in the spread of HIV. Moreover, this study indicates that drug resistance transmission may have decreased recently in Switzerland through the increased frequency of infection with HIV non-B subtypes and the steady increase of patients with undetectable viraemia.
Assuntos
Farmacorresistência Viral , Infecções por HIV/transmissão , HIV-1/efeitos dos fármacos , Doença Aguda , Adolescente , Adulto , Idoso , Farmacorresistência Viral/genética , Feminino , Variação Genética , Infecções por HIV/epidemiologia , Infecções por HIV/imunologia , Infecções por HIV/virologia , Protease de HIV/genética , Transcriptase Reversa do HIV/genética , HIV-1/classificação , HIV-1/enzimologia , HIV-1/genética , Humanos , Masculino , Pessoa de Meia-Idade , Filogenia , Suíça/epidemiologiaRESUMO
OBJECTIVE: To evaluate the immunological and virological responses to highly active antiretroviral therapy (HAART) in blood and lymphoid compartments of HIV-1-infected patients at an early stage of infection. DESIGN: An open-label, observational, non-randomized, prospective trial of outpatients attending the Centre of Clinical Investigation in Infectious Diseases, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland. SUBJECTS: Forty-one antiretroviral-naive HIV-1-infected adults with 400 CD4 T cells/microl or greater and 5000 plasma HIV-1-RNA copies/ml or greater were enrolled, and 32 finished the study. Forty-nine HIV-negative individuals were included as controls. All subjects gave written informed consent. INTERVENTIONS: All patients received abacavir 300 mg by mouth every 12 h and amprenavir 1200 mg by mouth every 12 h for 72 weeks. MAIN OUTCOME MEASURES: The extent of immune reconstitution in blood and lymph nodes after 72 weeks of HAART was evaluated, and compared with immunological measures of 49 HIV-negative subjects. RESULTS: Virus replication was effectively suppressed (-3.5 log10 at week 72). Substantial increments of CD4 T cell count in blood and percentage in lymph nodes were observed over time, and these measures were comparable to HIV-negative subjects by week 24 in blood and by week 48 in lymph nodes. The increase was equally distributed between naive and memory CD4 T cells. Recovery of HIV-specific CD4 responses occurred in 40% of patients. CONCLUSION: The initiation of HAART at an early stage of established HIV infection induces systemic quantitative normalization of CD4 T cells, a partial recovery of HIV-specific CD4 cell responses, and effective and durable suppression of virus replication.
Assuntos
Terapia Antirretroviral de Alta Atividade , Didesoxinucleosídeos/uso terapêutico , Infecções por HIV/tratamento farmacológico , HIV-1/fisiologia , Sulfonamidas/uso terapêutico , Adolescente , Adulto , Idoso , Contagem de Linfócito CD4 , Relação CD4-CD8 , Carbamatos , Feminino , Furanos , Infecções por HIV/imunologia , Infecções por HIV/virologia , Inibidores da Protease de HIV/uso terapêutico , HIV-1/efeitos dos fármacos , Humanos , Linfonodos/imunologia , Linfonodos/patologia , Ativação Linfocitária , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , RNA Viral/sangue , Inibidores da Transcriptase Reversa/uso terapêutico , Carga ViralRESUMO
The prevalence, clinical presentation, and risk factors for hyperlactatemia among patients receiving antiretroviral therapy was determined during a 1-month period for patients in the Swiss HIV Cohort Study. Overall, 73 (8.3%) of 880 patients presented an increase in serum lactate of >1.1 times the upper normal limit (UNL). For 9 patients (1%), lactate elevation was moderate or severe (>2.2 times the UNL). Patients who presented with hyperlactatemia were more likely to be receiving stavudine with or without didanosine (odds ratio, 2.7; 95% confidence interval, 1.5-4.8), as compared with patients who received zidovudine-based regimens. The risk increased with increasing time receiving stavudine with or without didanosine. The association between hyperlactatemia and stavudine with or without didanosine was not biased by these medications being more recently available and, therefore, being given preferentially to patients who had prolonged use of nucleoside analog reverse-transcriptase inhibitors. Hyperlactatemia was associated with lipoatrophy, hyperlipidemia, and hyperglycemia. Age, sex, or stage of infection with human immunodeficiency virus were not predictive of hyperlactatemia. Determination of lactate levels may prove useful in the screening for mitochondrial toxicity.
Assuntos
Acidose Láctica/etiologia , Fármacos Anti-HIV/efeitos adversos , Didanosina/efeitos adversos , Inibidores da Transcriptase Reversa/efeitos adversos , Estavudina/efeitos adversos , Zidovudina/efeitos adversos , Acidose Láctica/diagnóstico , Acidose Láctica/epidemiologia , Adulto , Estudos de Coortes , Feminino , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Prevalência , Fatores de Risco , SuíçaRESUMO
Among 504 cases of AIDS diagnosed between 1983 and 1990, there were 86 patients (17%) with toxoplasma encephalitis (TE). All were symptomatic at the time of diagnosis. General signs such as fever, neck stiffness, or headache were present in 87.2%, and 75.6% had focal signs. The primary means of diagnosis was computerized tomographic scanning, revealing 169 lesions of which 80% were immediately contrast-enhancing. All patients had IgG antibodies against Toxoplasma gondii either before (74 of 75 evaluable patients) or at the time of diagnosis of TE (73 of 75). Elevated antibody titers were present in 44% of evaluable patients, compared to 11% of patients with AIDS and other opportunistic infections. Initial treatment was pyrimethamine plus sulfonamides in 65 patients, and pyrimethamine plus clindamycin in 12 patients, with other combinations or no treatment accounting for the remainder. Life-table analysis of the time to discontinuation of treatment because of suspected side effects suggested that sulfadiazine was significantly more toxic, with 48% of patients experiencing an interruption in treatment after 30 days, than pyrimethamine (12%) or clindamycin (24%). The 30-day mortality rate was 12%, and median survival was 310 days after diagnosis, 530 in patients treated with zidovudine and 190 days in those not so treated. Of 82 evaluable patients, 16 relapsed once and 4 of these more than once. The risk of relapse was 27% 1 year after diagnosis of a first episode of TE.
Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , Toxoplasmose Cerebral/epidemiologia , Síndrome da Imunodeficiência Adquirida/sangue , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Adulto , Antibacterianos/administração & dosagem , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêutico , Anticorpos Antiprotozoários/sangue , Biópsia , Linfócitos T CD4-Positivos , Líquido Cefalorraquidiano/química , Feminino , Hospitais Universitários , Humanos , Imunoglobulina G/imunologia , Contagem de Leucócitos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida , Suíça/epidemiologia , Tomografia Computadorizada por Raios X , Toxoplasmose Cerebral/diagnóstico , Toxoplasmose Cerebral/tratamento farmacológico , Zidovudina/uso terapêuticoRESUMO
The role of stochastic effects and seed dispersal limitations in maintaining the diversity of a tree community is investigated by means of a forest growth simulator called TROLL. This simulator makes it possible to investigate impacts on the spatial distribution and the extinction probability of plant species. I present the results of a two-species competition scenario. Coexistence is found to be possible for competitively dissimilar species, and the criterion for this coexistence is given analytically in the reaction-diffusion approximation. A higher frequency of tree falls implies a smaller extinction probability of least adapted species. The multispecies model is also investigated. A mathematical quantity-the persistence function-permits measurement of the ability of a species to out compete other species locally. This quantity is compared with the average time to extinction, and it is computed for the TROLL simulator. I interpret the shape of this function in light of available information on the persistence function in simple interacting particle systems. These results indicate an analogy between the dynamics of forest communities and a simple discrete and spatially explicit model, the voter model. The ecological implications of this analogy are discussed and are extended to species-rich communities.
RESUMO
Patients with AIDS but without pneumocystis carinii pneumonia, patients with advanced AIDS-related complex (ARC), and asymptomatic patients with less than 200 CD4-positive lymphocytes/mm3 were randomized to one of two groups: group I: Inhalation of 300 mg of pentamidine every 28 days; group II: Inhalation of placebo (300 mg of Na isethionate) every 28 days. From May to November 28, 1989, 160 patients have entered the trial. Inhalations were well tolerated, with only a 6% use of bronchodilators and a 15% incidence of cough. Until now five patients died, none of them drug related. So far, six patients have developed pneumocystis carinii pneumonia; four of these were on pentamidine, and two on placebo. Five of the six cases occurred before the second inhalation. Recruitment will continue until 250 patients are enrolled.