Intelligent digital tools for screening of brain connectivity and dementia risk estimation in people affected by mild cognitive impairment: the AI-Mind clinical study protocol

More than 10 million Europeans show signs of mild cognitive impairment (MCI), a transitional stage between normal brain aging and dementia stage memory disorder. The path MCI takes can be divergent; while some maintain stability or even revert to cognitive norms, alarmingly, up to half of the cases progress to dementia within 5 years. Current diagnostic practice lacks the necessary screening tools to identify those at risk of progression. The European patient experience often involves a long journey from the initial signs of MCI to the eventual diagnosis of dementia. The trajectory is far from ideal. Here, we introduce the AI-Mind project, a pioneering initiative with an innovative approach to early risk assessment through the implementation of advanced artificial intelligence (AI) on multimodal data. The cutting-edge AI-based tools developed in the project aim not only to accelerate the diagnostic process but also to deliver highly accurate predictions regarding an individual's risk of developing dementia when prevention and intervention may still be possible. AI-Mind is a European Research and Innovation Action (RIA H2020-SC1-BHC-06-2020, No. 964220) financed between 2021 and 2026. First, the AI-Mind Connector identifies dysfunctional brain networks based on high-density magneto- and electroencephalography (M/EEG) recordings. Second, the AI-Mind Predictor predicts dementia risk using data from the Connector, enriched with computerized cognitive tests, genetic and protein biomarkers, as well as sociodemographic and clinical variables. AI-Mind is integrated within a network of major European initiatives, including The Virtual Brain, The Virtual Epileptic Patient, and EBRAINS AISBL service for sensitive data, HealthDataCloud, where big patient data are generated for advancing digital and virtual twin technology development. AI-Mind's innovation lies not only in its early prediction of dementia risk, but it also enables a virtual laboratory scenario for hypothesis-driven personalized intervention research. This article introduces the background of the AI-Mind project and its clinical study protocol, setting the stage for future scientific contributions.

Boosting precision crop protection towards agriculture 5.0 via machine learning and emerging technologies: A contextual review

Crop protection is a key activity for the sustainability and feasibility of agriculture in a current context of climate change, which is causing the destabilization of agricultural practices and an increase in the incidence of current or invasive pests, and a growing world population that requires guaranteeing the food supply chain and ensuring food security. In view of these events, this article provides a contextual review in six sections on the role of artificial intelligence (AI), machine learning (ML) and other emerging technologies to solve current and future challenges of crop protection. Over time, crop protection has progressed from a primitive agriculture 1.0 (Ag1.0) through various technological developments to reach a level of maturity closelyin line with Ag5.0 (section 1), which is characterized by successfully leveraging ML capacity and modern agricultural devices and machines that perceive, analyze and actuate following the main stages of precision crop protection (section 2). Section 3 presents a taxonomy of ML algorithms that support the development and implementation of precision crop protection, while section 4 analyses the scientific impact of ML on the basis of an extensive bibliometric study of >120 algorithms, outlining the most widely used ML and deep learning (DL) techniques currently applied in relevant case studies on the detection and control of crop diseases, weeds and plagues. Section 5 describes 39 emerging technologies in the fields of smart sensors and other advanced hardware devices, telecommunications, proximal and remote sensing, and AI-based robotics that will foreseeably lead the next generation of perception-based, decision-making and actuation systems for digitized, smart and real-time crop protection in a realistic Ag5.0. Finally, section 6 highlights the main conclusions and final remarks.

Plant functional diversity is affected by weed management through processes of trait convergence and divergence

Weed management involving tillage and/or herbicides has generally led to a decline of plant diversity in agroecosystems, with negative impacts on ecosystem services provision. The use of plant covers has become the predominant alternative in vineyard management, with numerous studies focusing on analyzing the advantages and disadvantages of plant covers compared to the aforementioned management. Although the impacts of weed management on taxonomic diversity have been widely studied, many gaps remain on their effects on plant functional diversity. As plant functional diversity is linked to the delivery of key ecosystem services in agroecosystems, understanding these effects could enable the development of more sustainable practices. From 2008 to 2018, a long-term trial was carried out in a Mediterranean vineyard to assess different agricultural practices. In this article, we examined how weed management, as well as irrigation use, could affect plant functional diversity. Based on 10 functional traits, such as plant height, specific leaf area or seed mass, we measured different indices of functional diversity and used null models to detect processes of trait convergence and divergence. Our results revealed that weed management and irrigation use had a significant effect on plant functional diversity. Mown plots showed the highest functional richness but were functionally convergent, since mowing was a strong functional filter on most of the traits. Tillage also behaved as a functional filter on some vegetative traits, but favored the divergence of certain reproductive traits. Herbicide-treated and irrigated plots showed the highest values of functional divergence by promoting more competitive species with more divergent trait values. The effect of weed management on these community assembly processes was shaped by the use of irrigation in vineyard rows, leading to functional divergence in those vegetative traits related to resource acquisition and seed mass. These results suggest that greater functional diversity may be associated with the bias caused by higher occurrence of competitive species (e.g. Convolvulus arvensis, Sonchus asper) with contrasting values for certain traits. Therefore, since these species are considered harmful to crops, higher plant functional diversity might not be a desirable indicator in agroecosystems.

Comparing UAV-Based Technologies and RGB-D Reconstruction Methods for Plant Height and Biomass Monitoring on Grass Ley

Pastures are botanically diverse and difficult to characterize. Digital modeling of pasture biomass and quality by non-destructive methods can provide highly valuable support for decision-making. This study aimed to evaluate aerial and on-ground methods to characterize grass ley fields, estimating plant height, biomass and volume, using digital grass models. Two fields were sampled, one timothy-dominant and the other ryegrass-dominant. Both sensing systems allowed estimation of biomass, volume and plant height, which were compared with ground truth, also taking into consideration basic economical aspects. To obtain ground-truth data for validation, 10 plots of 1 m² were manually and destructively sampled on each field. The studied systems differed in data resolution, thus in estimation capability. There was a reasonably good agreement between the UAV-based, the RGB-D-based estimates and the manual height measurements on both fields. RGB-D-based estimation correlated well with ground truth of plant height ( R 2 > 0.80 ) for both fields, and with dry biomass ( R 2 = 0.88 ), only for the timothy field. RGB-D-based estimation of plant volume for ryegrass showed a high agreement ( R 2 = 0.87 ). The UAV-based system showed a weaker estimation capability for plant height and dry biomass ( R 2 < 0.6 ). UAV-systems are more affordable, easier to operate and can cover a larger surface. On-ground techniques with RGB-D cameras can produce highly detailed models, but with more variable results than UAV-based models. On-ground RGB-D data can be effectively analysed with open source software, which is a cost reduction advantage, compared with aerial image analysis. Since the resolution for agricultural operations does not need fine identification the end-details of the grass plants, the use of aerial platforms could result a better option in grasslands.

High-Throughput Phenotyping of Bioethanol Potential in Cereals Using UAV-Based Multi-Spectral Imagery

Bioethanol production obtained from cereal straw has aroused great interest in recent years, which has led to the development of breeding programs to improve the quality of lignocellulosic material in terms of the biomass and sugar content. This process requires the analysis of genotype-phenotype relationships, and although genotyping tools are very advanced, phenotypic tools are not usually capable of satisfying the massive evaluation that is required to identify potential characters for bioethanol production in field trials. However, unmanned aerial vehicle (UAV) platforms have demonstrated their capacity for efficient and non-destructive acquisition of crop data with an application in high-throughput phenotyping. This work shows the first evaluation of UAV-based multi-spectral images for estimating bioethanol-related variables (total biomass dry weight, sugar release, and theoretical ethanol yield) of several accessions of wheat, barley, and triticale (234 cereal plots). The full procedure involved several stages: (1) the acquisition of multi-temporal UAV images by a six-band camera along different crop phenology stages (94, 104, 119, 130, 143, 161, and 175 days after sowing), (2) the generation of ortho-mosaicked images of the full field experiment, (3) the image analysis with an object-based (OBIA) algorithm and the calculation of vegetation indices (VIs), (4) the statistical analysis of spectral data and bioethanol-related variables to predict a UAV-based ranking of cereal accessions in terms of theoretical ethanol yield. The UAV-based system captured the high variability observed in the field trials over time. Three VIs created with visible wavebands and four VIs that incorporated the near-infrared (NIR) waveband were studied, obtaining that the NIR-based VIs were the best at estimating the crop biomass, while the visible-based VIs were suitable for estimating crop sugar release. The temporal factor was very helpful in achieving better estimations. The results that were obtained from single dates [i.e., temporal scenario 1 (TS-1)] were always less accurate for estimating the sugar release than those obtained in TS-2 (i.e., averaging the values of each VI obtained during plant anthesis) and less accurate for estimating the crop biomass and theoretical ethanol yield than those obtained in TS-3 (i.e., averaging the values of each VI obtained during full crop development). The highest correlation to theoretical ethanol yield was obtained with the normalized difference vegetation index (R ² = 0.66), which allowed to rank the cereal accessions in terms of potential for bioethanol production.

Treatment of hepatitis C with new fixed dose combinations

INTRODUCTION

The advent of oral direct-acting antivirals (DAA) has revolutionized the hepatitis C virus (HCV) therapeutic landscape providing cure rates over 90%. However, a subset of patients remains at higher risk for treatment failure, including those infected with: i) genotype 3 and cirrhosis; ii) resistance-associated substitutions (RAS) occurring either as natural polymorphisms or selected after prior DAA failure; and iii) poor drug adherence associated with social disabilities (homeless, psychiatric illnesses, injection drug use, alcoholism, etc.). Whereas discovery of new DAA with increased antiviral activity across all genotypes and over RAS may enhance efficacy, development of fixed dose combinations (FDC) may be the best way to improve drug adherence in difficult-to-treat HCV populations. Areas covered: Three FDC regimens are in the last steps of clinical development for treating hepatitis C. Two distinct nucleotide analogues that inhibit the HCV polymerase, sofosbuvir and uprifosbuvir, are part of the FDC from Gilead and Merck, respectively. The AbbVie dual FDC does not include a polymerase inhibitor. All three new FDC include second-generation NS3 protease inhibitors and NS5A inhibitors active across all HCV genotypes and over common RAS. Expert opinion: Hepatitis C cure rates over 95% are expected with all three next-coming DAA, even in the most difficult-to-treat and/or cure patient populations. These regimens would be particularly needed for the growing number of prior DAA failures. Co-formulations and 8-week shorter treatment lengths will help to overcome drug adherence challenges in certain populations.

Dual antiretroviral therapy for HIV infection

INTRODUCTION

For two decades, triple combinations of antiretrovirals have been the standard treatment for HIV infection. The challenges of such lifelong therapy include long-term side effects, high costs and reduced drug adherence. The recent advent of more potent and safer antiretrovirals has renewed the interest for simpler HIV regimens. Areas covered: We discuss the pros and cons of dual antiretroviral therapies in both drug-naïve and in treatment-experienced patients with viral suppression (switch strategy). Expert opinion: Some dual antiretroviral regimens are safe and efficacious, particularly as maintenance therapy. At this time, combinations of dolutegravir plus rilpivirine represent the best dual regimen. Longer follow-up and larger study populations are needed before supporting dolutegravir plus lamivudine. In contrast, dual therapy based on maraviroc is less effective. Although dual regimens with boosted protease inhibitors plus either lamivudine or raltegravir may be effective, they are penalized by metabolic side effects and risk for drug interactions. The newest dual regimens could save money, reduce toxicity and spare drug options for the future. For the first time in HIV therapeutics, less can be more. Dual therapy switching has set up a new paradigm in HIV treatment that uses induction-maintenance.

A New HIV Paradigm: Dual Antiretroviral Regimens as Maintenance Therapy

Since the advent of triple combination antiretroviral therapy in 1996, the prognosis of HIV-infected persons has improved drastically. The clinical benefits of HAART derive from producing sustained viral load suppression and CD4 gains. The major drawbacks of the first HAART regimens were common adverse events and high pill burden, which resulted in difficult drug adherence and led to frequent discontinuations and selection of drug resistance.

Rate and predictors of treatment failure to all-oral HCV regimens outside clinical trials

BACKGROUND

Cure rates above 90% have been reported in most Phase III clinical trials using distinct all-oral direct-acting antivirals (DAAs) in chronic hepatitis C patients. Preliminary results in real-world patients have confirmed this, although efficacy tends to be lower.

METHODS

All consecutive chronic hepatitis C patients treated with all-oral DAA regimens at three hepatitis clinics in Spain were retrospectively examined. Host and viral factors were tested as predictors of treatment failure.

RESULTS

A total of 363 chronic hepatitis C patients had completed a course of all-oral DAA therapy outside clinical trials up to the end of 2015. All but 14 (4%) patients achieved sustained virological response. There were 10 failures that occurred after 12 weeks of sofosbuvir-ledipasvir, despite 5 of them being on ribavirin. All failures but one were relapses. The only patient with viral breakthrough selected NS5B L159F and NS5A Y93H. In multivariate analyses, only advanced liver fibrosis (Metavir F3-F4) and HIV coinfection were significantly associated with treatment failure. A trend towards lower response was seen for HCV genotype 4.

CONCLUSIONS

Treatment failures outside clinical trials are roughly seen in 4% of chronic hepatitis C patients who complete a course of all-oral DAA therapy, resembling what is seen in registration trials. In our series, outcomes were not significantly influenced by ribavirin addition, IL28B polymorphisms, HCV genotype, high baseline HCV RNA or prior interferon failure. However, advanced liver fibrosis and HIV coinfection were significantly associated with treatment failure. Our findings support that there is still room for individualization of current DAA therapy.

Prevention and management of treatment failure to new oral hepatitis C drugs

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has become a curable disease. Sustained virologic response rates above 90% have been achieved with recommended direct-acting antiviral (DAA) combinations in most registration trials. However, outcomes in real-world patients are lower. In patients experiencing DAA failure, resistance-associated variants (RAVs) are almost universally selected. At this time it is unclear when and how to re-treat hepatitis C in patients with prior DAA failure.

AREAS COVERED

The rate of DAA failure and predictors of lack of treatment response using distinct DAA combinations are analyzed. We discuss the management of HCV treatment failure and the impact of RAVs on re-treatment strategies.

EXPERT OPINION

Failure to DAA combinations occurs more often in chronic hepatitis C patients with baseline predictors of poor response, such as those with RAVs, genotypes 3 or 1a, advanced liver cirrhosis, elevated serum HCV-RNA and perhaps HIV coinfection. Impaired antiviral efficacy is more frequent when multiple factors are present. On-treatment predictors of DAA failure are poor drug adherence and development of side effects. Extending the length of therapy, adding ribavirin and/or using DAA from other drug families may allow successful re-treatment of most prior DAA failures.

Delta hepatitis: new approaches to therapy

Hepatitis delta virus (HDV) infection is a neglected disease despite causing the most severe form of viral hepatitis. Over 15 million people are infected worldwide. IFN-α is largely inefficient and poorly tolerated. The discovery of sodium taurocholate cotransporting polypeptide as the cell receptor for HBV (and consequently for HDV) has allowed development of viral entry inhibitors (i.e., myrcludex-B). More recently, prenylation inhibitors (i.e., lonafarnib) that disrupt virion assembly are being tested. At this time, sustained suppression of HDV replication is the primary goal of hepatitis delta treatment, being associated with normalization of liver enzymes and histological improvement. The lack of persistent forms of HDV-RNA could provide unique opportunities for hepatitis delta cure using specific antivirals, even in the face of persistent HBV cccDNA.

New hepatitis C therapies for special patient populations

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has become a curable disease. More than 90% sustained virologic response rates have been obtained with 8-24 weeks of treatment with distinct combinations of direct-acting antivirals (DAA) in most registration trials. However, outcomes in real-world patients tend to be lower and treatment of special patient populations is often challenging.

AREAS COVERED

We address the treatment of chronic hepatitis C with DAA in major special patient populations, such as HIV-positive persons, transplant recipients, patients with advanced cirrhosis, renal insufficiency, hepatitis B or D coinfection, injection drug users (IDUs) and prior DAA failures.

EXPERT OPINION

Drug interactions between DAA and medications given to persons with HIV infection or transplant recipients can result in treatment failure and adverse events. Severe organ dysfunction as in kidney insufficiency or decompensated cirrhosis may lead to DAA overexposure and toxicities. Dysfunctional social circumstances and behavior are associated to poor drug adherence and increased risk for HCV re-infection in active IDUs. Finally, DAA response might be impaired by viral interference in patients with hepatitis B or D coinfection or drug resistance in HCV either at baseline or after prior DAA failures.

Rate and predictors of serum HCV-RNA >6 million IU/mL in patients with chronic hepatitis C

BACKGROUND

Baseline serum HCV-RNA predicts sustained virological response in chronic hepatitis C patients treated with antiviral therapy. A threshold at 6 million IU/mL has been proposed to best discriminate treatment outcomes on sofosbuvir-based regimens. In comparison with the general population, immunosuppressed individuals exhibit greater viral load values.

OBJECTIVES

To estimate the rate and predictors of serum HCV-RNA above 6 millionIU/mL in chronic hepatitis C patients on care outside clinical trials.

STUDY DESIGN

Serum HCV-RNA values recorded from all chronic hepatitis C patients consecutively attended at our clinic during the last decade were analyzed. Testing had been performed using the COBAS TaqMan HCV test v2.0.

RESULTS

A total of 816 individuals with detectable serum HCV-RNA were identified. The main characteristics of this population were as follows: mean age 48.6 years-old; 73.4% males; mean ALT 82.6IU/L; mean HCV-RNA 6.02logIU/mL; 80.6% HCV genotypes 1 or 4; 34.9% advanced liver fibrosis; 35.4% IL28B-CC alleles. HIV coinfection in 78.7%, of whom 91% were on antiretroviral therapy. Overall, 127 (15.6%) had serum HCV-RNA values >6 millionIU/mL. This high viremia was found in 18.2% of HIV-positive versus 5.7% of HIV-negative subjects (p<0.001). In multivariate analysis, serum HCV-RNA >6 millionIU/mL was only significantly associated with HIV coinfection (OR: 4.03; 95% CI: 1.98-8.19, p<0.01) and HCV genotypes 1 or 4 (OR: 1.88; 95% CI: 1.05-3.37, p=0.03).

CONCLUSIONS

Serum HCV-RNA >6 millionIU/mL is roughly seen in 6% of chronic hepatitis C monoinfected patients, and increases up to 18% in HIV coinfection.

Dual antiviral therapy for HIV and hepatitis C - drug interactions and side effects

INTRODUCTION

Roughly 20% of HIV-positive persons worldwide are coinfected with hepatitis C virus (HCV). The recent advent of direct-acting antivirals (DAA) that cure most hepatitis C patients has attracted much attention. Knowledge on drug interactions between DAA and antiretrovirals (ARV) may allow maximizing antiviral efficacy while minimizing drug-related toxicities.

AREAS COVERED

We review the most frequent side effects and clinically significant drug interactions between DAA and ARV. We further discuss how they can be prevented and managed in HIV/HCV-coinfected patients.

EXPERT OPINION

The safety profile of current DAA and the most recently approved ARV is quite favorable. Interactions between DAA and ARV could be frequent in clinical practice. The most common drug interactions affect drug metabolism by inducing or inhibiting the cytochrome P450 system, leading to abnormal drug exposures. Throughout this mechanism HCV and HIV protease inhibitors interact, especially when co-formulated with ritonavir as a pharmacoenhancer, and non-nucleoside HCV and HIV polymerase inhibitors. In contrast, HIV and HCV nucleos(t)ide polymerase inhibitors, and most HCV NS5A inhibitors (i.e., ledipasvir) and HIV integrase inhibitors (i.e., dolutegravir), do not or only marginally affect CYP450, and therefore are free of significant drug interactions. Exposure to HIV and HCV nucleos(t)ide analogues (i.e., tenofovir and sofosbuvir, respectively) is subject to induction/inhibition of drug transporters (i.e., P-glycoprotein).

High-Throughput 3-D Monitoring of Agricultural-Tree Plantations with Unmanned Aerial Vehicle (UAV) Technology

The geometric features of agricultural trees such as canopy area, tree height and crown volume provide useful information about plantation status and crop production. However, these variables are mostly estimated after a time-consuming and hard field work and applying equations that treat the trees as geometric solids, which produce inconsistent results. As an alternative, this work presents an innovative procedure for computing the 3-dimensional geometric features of individual trees and tree-rows by applying two consecutive phases: 1) generation of Digital Surface Models with Unmanned Aerial Vehicle (UAV) technology and 2) use of object-based image analysis techniques. Our UAV-based procedure produced successful results both in single-tree and in tree-row plantations, reporting up to 97% accuracy on area quantification and minimal deviations compared to in-field estimations of tree heights and crown volumes. The maps generated could be used to understand the linkages between tree grown and field-related factors or to optimize crop management operations in the context of precision agriculture with relevant agro-environmental implications.

Hepatic decompensation with sofosbuvir plus simeprevir in a patient with Child-Pugh B compensated cirrhosis

A 75-year-old male with compensated Child-Pugh B cirrhosis initiated sofosbuvir plus simeprevir, and developed hepatic decompensation and died a few days thereafter. High exposure to simeprevir leading to hepatotoxicity most likely explained this fatal outcome. This observation, along with similar cases recently reported in the literature, should raise awareness of the potential for decompensation in patients with advanced cirrhosis treated with simeprevir.

Drug interactions with new hepatitis C oral drugs

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has recently become a curable disease with antiviral therapy. The knowledge of drug interactions using direct-acting antivirals (DAA) may permit maximizing antiviral efficacy and avoiding drug-related toxicities. Ageing in the chronic hepatitis C population, along with added co-morbidities that require other medications, has increased the attention on drug interactions using DAA.

AREAS COVERED

This review provides an update of the most clinically significant pharmacokinetic and pharmacodynamic drug interactions occurring between currently available DAA and other medications. The review also revisits how drug interactions with DAA can be prevented and managed.

EXPERT OPINION

Interactions between DAA and other drugs are frequent in clinical practice. The most frequent drug interactions modify drug metabolism by inducing or inhibiting the cytochrome P450, leading to abnormal drug exposures. Through this mechanism HCV protease inhibitors, especially when co-formulated with ritonavir as pharmacoenhancer, and non-nucleoside HCV polymerase inhibitors interact with other medications. In contrast, NS5B nucleos(t)ide analog inhibitors (i.e., sofosbuvir) and some HCV NS5A inhibitors (i.e., ledipasvir), which do not or only marginally affect CYP450, are relatively free of significant pharmacokinetic interactions. However, exposure to HCV nucleos(t)ide analogs may be influenced by induction/inhibition of drug transporters (i.e., P-glycoprotein) as well as by pharmacodynamic interference with other nucleos(t)ide analogs used as antivirals or cancer drugs. Drug interactions for some NS5A inhibitors (i.e., daclatasvir) are generally moderate and can be managed with dose adjustments.

Advances in treating drug-resistant hepatitis B virus in HIV-infected patients

INTRODUCTION

Treatment of HIV infection with nucleos(t)ide analogs active against hepatitis B virus (HBV) highly improves hepatic outcomes in HIV-HBV coinfected patients, especially when tenofovir (TDF) is part of the antiviral regimen. Drug resistance has been the major drawback and must remain as the most important caveat when planning to treat dually or HIV and HBV independently in coinfected patients.

AREAS COVERED

The use of lamivudine (LAM) as the only active anti-HBV agent should strongly be discouraged in HIV-HBV coinfected patients, although it might be considered for individuals with low serum HBV-DNA and in the absence of liver cirrhosis as an exception. In any other case drug resistance may cause any clinical benefit of this antiviral HBV therapy to disappear, and lead to cross-resistance with other antivirals and even occasionally select for HBV vaccine escape mutants. In cirrhotics, liver enzyme flares may be accompanied by life-threatening decompensation. Entecavir is generally not recommended as an anti-HBV agent in HIV-HBV coinfected patients given its low residual antiretroviral activity and potential for selection of resistance mutations in HIV. Adefovir is not active against HIV using HBV dosing and is no longer recommended as HBV therapy given its limited antiviral effect. Finally, telbivudine is not active against HIV, it is less potent than TDF against HBV and depicts low barrier to resistance and cross-resistance to LAM or emtricitabine.

EXPERT OPINION

The introduction of TDF has drastically reduced the clinical relevance of hepatitis B drug resistance in HIV-HBV coinfected individuals. The use of LAM as the only active anti-HBV agent should strongly be discouraged in this population.

RNA viruses at the forefront of human infections - HIV, hepatitis C, and now Ebola

AIDS emerged in 1981, breaking a period of proud medical progresses in controlling infectious diseases with antimicrobials and vaccines. In an unprecedented way, HIV has attracted much attention for three decades, driving the discovery of new extraordinary molecular diagnostic tools and antiviral drugs. As a result, advances in antiretroviral therapy have made it possible to change HIV infection into a chronic illness. However, the prospects for HIV eradication in the short term are not envisioned for the more than 35 million people worldwide estimated to be living with HIV.

[Imported malaria and HIV infection in Madrid. Clinical and epidemiological features]

INTRODUCTION

Few data are available in Spain data on human immunodeficiency virus (HIV) patients coinfected with malaria. This study has aimed to determine the epidemiological and clinical characteristics of imported malaria in patients coinfected with HIV.

PATIENTS AND METHODS

A case-series retrospective study was performed using the patient's medical records. The study population consisted on patients diagnosed with malaria attended in our center from january 1, 2002 to december 31, 2007.

RESULTS

A total of 484 episodes of malaria, 398 of which were included in this study, were identified. Co-infection with HIV was described in 32 cases. All of them occurred in individuals presumably with some degree of semi-immunity. In the coinfected group, there were 13 cases (40.6%) asymptomatic, whereas this event occurred in 99 cases of patients not coinfected (37.2%) (P=0.707). The greater presence of anemia in co-infected patients (62.5% vs 32.3% in non-coinfected [P=0.001]) stands out.

CONCLUSIONS

In present study, the clinical presentation forms were similar, regardless of the presence or absence of HIV infection. Although the study population does not reflect all possible scenarios of malaria and HIV coinfection, our results indicate the reality of patients attended in the Autonomous Community of Madrid.

[Imported malaria in adults. Clinical, epidemiological and analytical features]

INTRODUCTION

Up to now, the epidemiological and clinical features of imported malaria in Spain have been described in small series from general hospitals. Almost all diagnosis had been made based on symptomatic patients. The aim of this study has been to determine the epidemiological, clinical and laboratorial characteristics of imported malaria in a Reference Unit for Tropical Diseases.

PATIENTS AND METHODS

We performed a cross-sectional, observational and retrospective study. The series consisted of patients diagnosed of malaria who had been attended at the Hospital Carlos III from January 1, 2002 to December 31, 2007.

RESULTS

We identified 484 episodes of malaria, of which 398 cases were included in the analysis. Almost 50% of the patients were natives of endemic areas, while the rest were native-travelers or travelers. Most cases (88-98% according to the group) had not taken malaria chemoprophylaxis correctly when indicated. At the time of diagnosis, 30.4% of patients were asymptomatic and 28.1% of asymptomatic patients had anemia, 19.8% thrombocytopenia, 14% leukopenia, 5% hypocholesterolemia, 5% renal failure and 4.1% hypoglycemia. Low parasitemia was present in 97.5% of asymptomatic individuals compared to 80.5% of the symptomatic patients (P<0.001).

DISCUSSION

Absence of chemoprophylaxis (or poor compliance) is the main reason for malaria in individuals traveling to endemic areas. Malaria must be ruled out in individuals coming from tropical countries with compatible symptoms, and it also should be suspected in certain groups of asymptomatic individuals with abnormal laboratorial parameters.

A randomized trial comparing the efficacy and tolerability of two HAART strategies at two years in antiretroviral naive patients

BACKGROUND

The use of HAART combining 2 nucleoside analogues reverse transcriptase inhibitors (NRTIs) plus one protease inhibitor (PI) or 2 NRTIs + 1 non-nucleoside reverse transcriptase inhibitor (NNRTI) has shown comparable efficacy. The study was designed to compare long term (2 years) effectiveness of two antiretroviral (ARV) treatment strategies in patients not previously treated: starting with a nelfinavir based HAART switching to nevirapine in case of failure or side effects or the reverse sequence.

METHODS

This multicenter, randomized, open label clinical trial enrolled ARV-naïve HIV patients with CD4 counts below 500 cells/mm3. They were randomly assigned to start ddI + d4T + nelfinavir (switching to ZDV + 3TC + NEV in case of failure or toxicity) (PI-NEV arm) or ddI + d4T + nevirapine, switching to ZDV + 3TC + NFV in case of failure or toxicity (NEV-PI arm). The primary study endpoint was the Kaplan-Meier estimates of the time to failure after switching to second regimen if necessary (considering failure as two consecutive plasma HIV-1 RNA determinations above 200 copies/mL, death, a new category C event or toxicity leading to treatment discontinuation of the second regimen) after a minimum follow-up of two years.

RESULTS

A total of 137 patients were evaluable (67 and 70 in the PI-NEV and NEV-PI arms respectively). Baseline characteristics did not differ among groups. Kaplan-Meier estimates of time to failure did not show differences between the two arms neither in the on-treatment (OT) analysis (log rank test, p = 0.81) nor in the intent-to-treat (ITT) analysis (p = 0.58). At 24 months, the estimated proportion of patients free of failure were 72% and 66% respectively in the PI-NEV and NEV-PI arms OT analysis (p = 0.54) and 73% and 64% in the PI-NEV and NEV-PI arms in the ITT analysis (p = 0.49). The difference in the median in CD4+ lymphocyte count at 24 months was not significantly different in the two groups: 393 and 307 CD4 cells/mm3 in the PI-NEV and NEV-PI arms respectively (p = 0.167). The incidence of adverse events (AEs) in the two arms was very similar: 50 (75%) in the PI-NEV and 54 (70%) in the NEV-PI group, as it was for grade 3-4 AEs leading to drug switching.

CONCLUSION

At two years both treatments strategies (PI-NEV vs NEV-PI) had a high and comparable efficacy and were generally well tolerated.

Growing Bayesian network models of gene networks from seed genes

MOTIVATION

For the last few years, Bayesian networks (BNs) have received increasing attention from the computational biology community as models of gene networks, though learning them from gene-expression data is problematic. Most gene-expression databases contain measurements for thousands of genes, but the existing algorithms for learning BNs from data do not scale to such high-dimensional databases. This means that the user has to decide in advance which genes are included in the learning process, typically no more than a few hundreds, and which genes are excluded from it. This is not a trivial decision. We propose an alternative approach to overcome this problem.

RESULTS

We propose a new algorithm for learning BN models of gene networks from gene-expression data. Our algorithm receives a seed gene S and a positive integer R from the user, and returns a BN for the genes that depend on S such that less than R other genes mediate the dependency. Our algorithm grows the BN, which initially only contains S, by repeating the following step R + 1 times and, then, pruning some genes; find the parents and children of all the genes in the BN and add them to it. Intuitively, our algorithm provides the user with a window of radius R around S to look at the BN model of a gene network without having to exclude any gene in advance. We prove that our algorithm is correct under the faithfulness assumption. We evaluate our algorithm on simulated and biological data (Rosetta compendium) with satisfactory results.

Detecting multivariate differentially expressed genes

BACKGROUND

Gene expression is governed by complex networks, and differences in expression patterns between distinct biological conditions may therefore be complex and multivariate in nature. Yet, current statistical methods for detecting differential expression merely consider the univariate difference in expression level of each gene in isolation, thus potentially neglecting many genes of biological importance.

RESULTS

We have developed a novel algorithm for detecting multivariate expression patterns, named Recursive Independence Test (RIT). This algorithm generalizes differential expression testing to more complex expression patterns, while still including genes found by the univariate approach. We prove that RIT is consistent and controls error rates for small sample sizes. Simulation studies confirm that RIT offers more power than univariate differential expression analysis when multivariate effects are present. We apply RIT to gene expression data sets from diabetes and cancer studies, revealing several putative disease genes that were not detected by univariate differential expression analysis.

CONCLUSION

The proposed RIT algorithm increases the power of gene expression analysis by considering multivariate effects while retaining error rate control, and may be useful when conventional differential expression tests yield few findings.

Cambios en la transmisión vertical del virus de la inmunodeficiencia humana: comparación de los años 1994 y 2004

BACKGROUND AND OBJECTIVE

Vertical transmission (VT) is the main route of human immunodeficiency virus (HIV) infection in children. Since the publication of PACTG 076 study in 1994, several preventive methods against the vertical transmission of the HIV have been developed. In this study, we compare the clinical and epidemiological profile of HIV-infected pregnant women and the VT rate in the years 1994 and 2004.

PATIENTS AND METHOD

We looked at maternal, obstetric and pediatric variables of HIV-infected women and their children, born in 1994 and 2004, who were followed in Hospital La Paz.

RESULTS

We included 40 mother-infant couples in 1994 and 35 couples in 2004. The HIV vertical transmission rate was 35% in 1994 and 0% in 2004. We did not find changes in Hepatitis C virus (HCV) vertical transmission. In 1994, HIV-infected mothers had a more advanced HIV-disease and the major route of HIV-transmission was the intravenous drug use. Vaginal delivery was more frequent and rupture of membranes was longer than in 2004. The main route of maternal HIV infection in 2004 was sexual contact. In this same year, the use of combination antiretroviral therapy, even during pregnancy, was generalized, the elective cesarean section was the most frequent form of delivery, and every newborn received zidovudine.

CONCLUSIONS

In the last decade, there have been important epidemiological changes in HIV-infected mothers in our society. The administration of antiretroviral therapy during pregnancy and to the newborn, as well as other obstetric strategies, can prevent HIV vertical transmission. Nevertheless, we did not find any change in the risk of HCV vertical transmission.

Bayesian analysis using continuous likelihood ratios for identifying pleural exudates

STUDY OBJECTIVES

To ascertain if equations that calculate continuous likelihood ratios (CLRs) for pleural exudates improve pleural fluid categorization, especially when false positive or false negative test results are obtained by using Light's criteria.

DESIGN AND SETTING

Retrospective review of the clinical and pleural fluid data from a consecutive series of patients with pleural effusion who underwent thoracentesis at the University Hospital Arnau de Vilanova (Lleida, Spain) over an 11-year period.

PATIENTS AND METHODS

A total of 1490 patients with pleural effusion (298 transudates and 1192 exudates) were recruited into the study. The presence of a transudate or exudate was established by clinical judgment. We examined the comparative diagnostic accuracy of 4 tests (i.e. pleural fluid protein and lactate dehydrogenase (LDH), and pleural fluid to serum protein and LDH ratios) for discriminating between transudates and exudates. Decision thresholds were determined by receiver operating characteristics (ROC) analysis. Equations for calculating CLRs derived from a logistic regression analysis based on a previously described method.

RESULTS

Individual pleural fluid tests did not differ in their diagnostic accuracies according to ROC analysis. We calculated CLRs for the elements of Light's criteria and pleural fluid protein, and also illustrated the sequential use of CLRs for determining posttest probabilities. Overall, CLR formulas had marginal performance for the correct categorization of pleural fluid.

CONCLUSIONS

CLRs provide a probabilistic statement as to the likelihood an effusion is a transudate or exudate. However, clinical judgment is little changed by the application of CLRs, and in doubtful cases a great amount of uncertainty remains. This Bayesian approach is likely to have no major impact on the clinical practice.

[Immunophenotype of progression to AIDS: deficiency, activation and dysfunction of CD4 and CD8 T-cells]

INTRODUCTION

One key piece of information required when deciding whether to initiate antiretroviral therapy is the risk of AIDS. The aim of this study was to better characterize the baseline immunophenotypic profile of patients with progression to AIDS.

MATERIAL AND METHODS

A cross-sectional analysis of the distribution of functional subpopulations of CD4+ and CD8+ T-lymphocytes in 85 intravenous drug addicts with HIV infection. The values observed on patient enrolment in a prospective study were analyzed. Those patients who progressed and did not progress were compared to the HIV-negative controls. Lymphocyte subpopulations were studied by flow cytometry, including the markers: CD3, CD4, CD7, CD8, CD45RO, CD38, HLA-DR and CD25.

RESULTS

The immunophenotypic profile that precedes progression to AIDS was mainly characterized by an increase in memory (CD45RO) activated cells and total activated CD4+ and CD8+ cells, and by an increase of T CD4+ cells that have loss expression of markers as receptor or the differentiation marker CD7 (CD7-). Patients not meeting laboratory criteria to initiate antiretroviral therapy (> 350 CD4+ T-cells and < 30,000 HIV-ARN-copies/ml) also showed increased levels of CD4+ and CD8+ activation subsets (CD4+CD38+DR+, CD8+CD38+).

DISCUSSION

The fact that immunological activation may contribute to immunological and clinical deterioration of HIV-positive patients might be an additional factor which should be taken into account when deciding whether to initiate antiretroviral therapy.

Multidrug-resistant tuberculosis without HIV infection: success with individualised therapy

OBJECTIVE

To evaluate the results of the treatment of non-HIV-infected multidrug-resistant tuberculosis (MDR-TB) patients admitted to a tuberculosis unit in a reference centre between June 1998 and December 2000.

RESULTS

Twenty-five patients were studied (23 men). Empirical treatment was selected according to drugs previously used and adjusted according to in vitro test results. Patients had previously received an average of 5.5 drugs and were resistant to an average of 4.7 drugs. They were treated with a median number of four drugs (an injectable drug plus three oral drugs) for a median of 18 months. Ofloxacin and cycloserine was used in 17 cases (68%), ethionamide/prothionamide in 18 (72%) and para-aminosalicylic acid in 12 patients (48%). Psychological support and counselling was provided. Two patients required surgery. Globally, 21 patients (84%) met cure criteria. After a 24-month follow-up, none of the 21 patients who successfully completed treatment presented relapse or death.

CONCLUSION

MDR-TB is a curable disease in non-HIV-infected patients. Individualised treatment regimens should be based on treatment history and the study of in vitro susceptibility and by promoting a relationship with the patient that makes adherence to treatment easier and minimises side effects.

Revaluación del método estándar (criterios de Light) para identificar exudados pleurales

BACKGROUND AND OBJECTIVES

Light's criteria remain the best method for separating pleural exudates from transudates. We assessed their operating characteristics, as well as those resulting from omitting the pleural fluid to serum lactate dehydrogenase (LDH) ratio from the original criteria (abbreviated Light criteria), in a large series of patients. We also searched for the best combination of pleural fluid parameters, including protein, LDH and cholesterol that identify exudates.

PATIENTS AND METHOD

We conducted a retrospective study of 1,490 consecutive patients with pleural effusion who underwent a diagnostic thoracentesis. There were 1,192 exudates and 298 transudates. Sensitivity, specificity, area under ROC curve, and odds ratio for both individual and combined pleural fluid parameters were calculated.

RESULTS

Light's criteria yielded 97.5% sensitivity and 80% specificity. Both abbreviated Light criteria (sensitivity: 95.4%; specificity: 83.3%) and the combined use in an "or" rule of pleural fluid protein and LDH (sensitivity: 95.4%; specificity: 80,2%) had similar discriminative properties than standard criteria.

CONCLUSIONS

Diagnostic separation of pleural effusions into exudates or transudates can be done effectively thorough the abbreviated Light criteria when the serum LDH value is not available. On the other hand, if venipuncture wants to be avoided (an unusual circumstance) the combination of pleural fluid protein and LDH represents an alternative to Light's criteria.

[Late nephrology referral influences on morbidity and mortality of hemodialysis patients. A provincial study]

OBJECTIVE

To evaluate the influence of late referral to nephrology of the patients with chronic renal failure in the morbimortality of the patients who start hemodialysis. SUBJETS AND METHODS: There were included in the study the patients who started hemodialysis (HD) as first form of treatment, and that survived at least three months in both hospitals of reference of the province of Huesca from january 1990 to december 2001. Patients who started HD after acute renal failure were excluded. Clinical and analytical data were determined for each patient at the start of HD and during the follow-up. Early (ER) and late referral (LR) were defined by the time of first nephrology encounter greather than or less than 4 months respectively, before HD initiation. Morbidity analysis (using multiple linear regression with rate of days of hospitalization as dependent variable) and global and anual during the first three years of follow-up survival analysis (using Cox proportional hazards regression) were carried out.

RESULTS

A total of 139 patients (78%) started HD in the ER group and 39 (22%) in LR group. Mean follow-up was similar in both (ER = 34.43 +/- 25.5 months; LR = 34.42 +/- 28.37 months). At the start of dialysis LR was associated to higher proportion of temporary catheters, lower level of hematocrit and albumin, higher comorbidity and higher levels of urea and creatinine. Risk factors selected by the model in the morbidity analysis were index of comorbidity (CI), late referral, serum albumin, urea reduction ratio (URR) and hematocrit (R2 = 0.334, F = 16.97, p < 0.005). The final equation of regression was: Rate of hospitalization's days = 101.12 + (2.45 x CI) - (12. 11 x LR) - (11.57 x Alb.) - (0.43 x PRU) - (0.83 x Hto). Variables selected by Cox's regression model that were associated with survival throughout complete follow-up were hematocrit (RR = -0,207, CI 95% 0.726-0.910, p < 0.0005), index of comorbidity (RR = 0,265, CI 95% 1.066-1.594, p = 0.007), PRU (RR = - 0,059, CI 95% 0.893-0.996, p = 0.038) and type of dialysis membrane (RR = 0,771, Cl 95% 0.260-0.822, p = 0.007). Nevertheless, in successive models fitting after 12, 24 and 36 months of follow-up the variable LR influenced in an independent way survival first two years, losing his significance later.

CONCLUSION

In our study patients of the group LR presented a worse clinical and metabolic situation at the beginning of the HD. Later there was demonstrated in this group a higher long-term morbidity and a lower survival the first two years.

Lopinavir/ritonavir as single-drug therapy for maintenance of HIV-1 viral suppression: 48-week results of a randomized, controlled, open-label, proof-of-concept pilot clinical trial (OK Study)

OBJECTIVE

This study evaluated maintenance with lopinavir/ritonavir monotherapy vs. continuing lopinavir/ritonavir and 2 nucleosides in HIV-infected patients with suppressed HIV replication.

DESIGN

Randomized, controlled, open-label, multicenter, pilot clinical trial.

METHODS

Adult patients were eligible if they had no history of virologic failure while receiving a protease inhibitor, were receiving 2 nucleosides + lopinavir/ritonavir (400/100 mg b.i.d.) for >1 month and had maintained serum HIV RNA <50 copies/mL for >6 months prior to enrollment.

RESULTS

Forty-two patients were randomly assigned 1:1 to continue or stop the nucleosides. At baseline there were no significant differences between groups in median CD4 cells/muL (baseline or nadir), pre-HAART (highly active antiretroviral therapy) HIV log10 viremia, or time with HIV RNA <50 copies/mL prior to enrollment. After 48 weeks of follow-up, percentage of patients remaining at <50 HIV RNA copies/mL (intention to treat, M = F) was 81% for the monotherapy group (95% CI: 64% to 98%) vs. 95% for the triple-therapy group (95% CI: 86% to 100%); P = 0.34. Patients in whom monotherapy failed had significantly worse adherence than patients who remained virally suppressed on monotherapy. Monotherapy failures did not show primary resistance mutations in the protease gene and were successfully reinduced with prerandomization nucleosides. Mean change in CD4 cells/microL: +70 (monotherapy) and +8 (triple) (P = 0.27). Mean serum fasting lipids remained stable in both groups. No serious adverse events were observed.

CONCLUSION

Most of the patients maintained with lopinavir/ritonavir monotherapy remain with undetectable viral load after 48 weeks. Failures of lopinavir/ritonavir monotherapy were not associated with the development of primary resistance mutations in the protease gene and could be successfully reinduced adding back prior nucleosides.

Abnormalities in the bone mineral metabolism in HIV-infected patients

OBJECTIVE

To evaluate bone mineral metabolism in HIV infected and asymptomatic patients receiving highly active antiretroviral therapy (HAART) containing protease inhibitors (PI) and naïve patients.

METHODS

We studied 30 asymptomatic HIV infected male patients, 13 in the naive group and 17 in the IP group, both without differences in demographics characteristics. We excluded women and patients with any known factor associated to osteopenia. We did a nutritional questionnaire, a DEXA scan in lumbar spine and femur, a study of CD4 lymphocytes, viral load and an analysis of bone formation and resorption markers in all patients. We compared vitamin D and PTH levels with a control group of healthy male volunteers age-pareated. For the statistical analysis we used the SPSS program.

RESULTS

Osteopenia was present in 17/30 (57%), 8/13 (61.5%) in the naïve group and 9/17 (53%) in the PI group (not significant differences). We found a vitamin D deficiency in 86% of patients, with mean serum levels that was found to be significantly lower than those from a healthy control group (p=0.04). Testosterone level was significantly related to bone mineral density in lumbar spine (p</=0.05).

CONCLUSIONS

HIV may be an individual risk factor in bone disorders, requiring calcium and vitamin D supplementation.

Single (B or C), dual (BC or BD) and triple (BCD) viral hepatitis in HIV-infected patients in Madrid, Spain

INTRODUCTION

There are very limited data about the prevalence of multiple hepatitis virus infections in HIV infected individuals. In HIV uninfected individuals with triple BCD hepatitis, hepatitis D virus (HDV) appears to be the dominant virus. However, in HIV infected patients with triple hepatitis it is not known if HDV replication inhibits hepatitis B virus (HBV) and/or hepatitis C virus (HCV) replication.

METHODS

We calculated the prevalence of single (B or C), dual (BC) and triple (BCD) hepatitis in 423 HIV-infected patients with positive HCV serum antibodies and/or positive serum HBsAg. In patients with multiple infections we performed an evaluation of serum markers of HBV, HCV and HDV replication.

RESULTS

The prevalence of multiple hepatitis was 4.7% (95% confidence interval, 2.7-6.7%). Multiple hepatitis occurred only among patients who acquired HIV through injection drug use. The most common multiple hepatitis was triple BCD. Patients with hepatitis BC and past or chronic hepatitis D were significantly more likely to have cirrhosis and a negative serum HBeAg and HCV PCR than patients with single hepatitis B or hepatitis C. Patients with chronic hepatitis D showed uniform suppression of HBV and HCV replication markers.

CONCLUSIONS

In our geographic area approximately 5% of HIV infected patients with hepatitis suffer multiple hepatitis virus infection. In patients with triple hepatitis BCD virus infection, HDV appears to be the dominant virus causing inhibition of both HBV and HCV replication.

Globally multimodal problem optimization via an estimation of distribution algorithm based on unsupervised learning of Bayesian networks

Many optimization problems are what can be called globally multimodal, i.e., they present several global optima. Unfortunately, this is a major source of difficulties for most estimation of distribution algorithms, making their effectiveness and efficiency degrade, due to genetic drift. With the aim of overcoming these drawbacks for discrete globally multimodal problem optimization, this paper introduces and evaluates a new estimation of distribution algorithm based on unsupervised learning of Bayesian networks. We report the satisfactory results of our experiments with symmetrical binary optimization problems.

Therapeutic immunization with an inactivated HIV-1 Immunogen plus antiretrovirals versus antiretroviral therapy alone in asymptomatic HIV-infected subjects

To determine whether the addition of an inactivated-gp120-depleted HIV-1 Immunogen to antiretrovirals (ARTs) conferred a beneficial effect on delaying time to virologic failure relative to that obtained by ARTs alone, a phase II clinical trial was performed in 243 asymptomatic, ART naïve, HIV-1 seropositive adults. The Cox model showed that HIV-1 Immunogen treatment was associated with a 34% decrease in the risk of virologic failure (P = 0.056). When the analysis incorporated baseline HIV-RNA stratification the risk of virologic failure in the HIV-1 Immunogen Arm was significantly reduced a 37% compared to the IFA placebo Arm (P = 0.034). The data suggest that therapeutic immunization plus ARTs could influence virologic control.

Bayesian network multi-classifiers for protein secondary structure prediction

Successful secondary structure predictions provide a starting point for direct tertiary structure modelling, and also can significantly improve sequence analysis and sequence-structure threading for aiding in structure and function determination. Hence the improvement of predictive accuracy of the secondary structure prediction becomes essential for future development of the whole field of protein research. In this work we present several multi-classifiers that combine the predictions of the best current classifiers available on Internet. Our results prove that combining the predictions of a set of classifiers by creating composite classifiers is a fruitful one. We have created multi-classifiers that are more accurate than any of the component classifiers. The multi-classifiers are based on Bayesian networks. They are validated with 9 different datasets. Their predictive accuracy results outperform the best secondary structure predictors by 1.21% on average. Our main contributions are: (i) we improved the best know predictive accuracy by 1.21%, (ii) our best results have been obtained with a new semi naïve Bayes approach named Pazzani-EDA and (iii) our multi-classifiers combine results of previously build classifiers predictions obtained through Internet, thanks to our development of a Java application.

Impact of tuberculosis on the course of HIV-infected patients with a high initial CD4 lymphocyte count

OBJECTIVE

To assess the influence of tuberculosis (TB) on the progression of human immunodeficiency virus (HIV) infection in patients without immunological impairment.

MATERIAL AND METHODS

In an observational study of retrospective cohorts, the evolution of 28 HIV-infected patients with TB and a CD4 lymphocyte count >500 x 10(6) cells/l was compared with 56 HIV-infected patients without TB. Each case was paired with two controls by CD4 lymphocyte count (+/-50 x 10(6)/l) and date of starting follow-up (+/-6 months). The progression of HIV infection was evaluated as: 1) immunological progression: time to CD4 lymphocyte count <200 x 10(6)/l; 2) clinical progression: time to development of acquired immune-deficiency syndrome (AIDS), excluding TB; 3) survival; and 4) global disease progression: time to the first defined event in 1, 2 and/or 3. The times to these events were estimated using Kaplan Meier curves.

RESULTS

There were no significant differences between the cohorts for age, sex and risk group. Faster immunological impairment (RR 2.94; 95%CI 1.46-8.6; P < 0.01), greater progression to AIDS (RR 4.01; 95%CI 1.66-9.69; P < 0.01), lower survival (RR 3.89; 95%CI 1.53-9.87; P < 0.05) and higher global disease progression (RR 2.82; 95%CI 1.57-5.09; P < 0.01) were found in the cohort of TB patients. These associations were still significant after adjustment for CD4 lymphocyte counts.

CONCLUSION

The diagnosis of TB in HIV-infected patients with a high initial CD4 lymphocyte count (>500 x 10(6)/l) was related to greater progression to AIDS and shorter survival.

Quantitation of Human Immunodeficiency Virus Type 1 RNA Loads in Cervicovaginal Secretions in Pregnant Women and Relationship Between Viral Loads in the Genital Tract and Blood

The purpose of this study was to analyze the quantitation of the human immunodeficiency virus type 1 RNA (HIV-1 RNA) in the genital tract of HIV-1-infected pregnant women and to evaluate a possible correlation with the viral load in blood plasma (Spearman's rank correlation coefficient). A total of 38 each of cervical, vaginal, and blood samples from 38 women were obtained during the third trimester of pregnancy for quantitation of the HIV-1 RNA load. Viral loads were determined by reverse transcription-polymerase chain reaction. The HIV-1 RNA viral load was detectable in 29 of the 38 (76.3%) blood samples, in 6 of the 38 (15.7%) cervical secretion samples, and in 8 of the 38 (21%) vaginal secretion samples. Overall, the correlation between the HIV-1 RNA viral load in the blood plasma and in cervical secretion samples was 0.51 ( P<0.001). However, the correlation disappeared ( r=0.27) when three patients with high blood plasma viral loads were eliminated from the statistical study. The viral load in the vaginal secretions did not correlate with that in the blood samples ( r=0.26). There were two cases in which HIV-1 RNA was undetectable in the blood and cervix but was detectable in vaginal secretions: one woman had 220 copies/ml and the other 68 copies/ml. These results suggest that pregnant women with undetectable viral loads in blood plasma are still at risk of transmitting the virus vertically during vaginal delivery. Because of this, antiretroviral prophylaxis during vaginal delivery must be administered to HIV-1-infected women and their newborns, regardless of the mother's viral load in plasma. In conclusion, quantification of cervicovaginal levels of HIV-1 may represent a useful tool for assessing the individual risk associated with a vaginal delivery and for guiding decisions about whether a scheduled caesarean should be recommended.

Prognosis and clinical evaluation of infection caused by Rhodococcus equi in HIV-infected patients: a multicenter study of 67 cases

OBJECTIVE

To assess the clinical characteristics and the factors that influenced the prognosis of patients with HIV and infection caused by Rhodococcus equi.

DESIGN

Observational, multicenter study in 29 Spanish general hospitals.

SETTING

These hospitals comprised a total of 20,250 beds for acute patients and served a population of 9,716,880 inhabitants.

PATIENTS

All patients with HIV and diagnosed R equi infection until September 1998.

RESULTS

During the study period, 19,374 cases of AIDS were diagnosed. Sixty-seven patients were included (55 male patients; mean +/- SD age, 31.7 +/- 5.8 years). At the time of diagnosis of R equi infection, the mean CD4+ lymphocyte count was 35/ micro L (range, 1 to 183/ micro L) and the stage of HIV infection was A3 in 10.4% of patients, B3 in 31.3%, C3 in 56.7%, and unknown in 1.5%. R equi was most commonly isolated in sputum (52.2%), blood cultures (50.7%), and samples from bronchoscopy (31.3%). Chest radiographic findings were abnormal in 65 patients (97%). Infiltrates were observed in all of them, with cavitations in 45 patients. The most active antibiotics against the strains isolated were vancomycin, amikacin, rifampicin, imipenem, ciprofloxacin, and erythromycin. After a mean follow-up of 10.7 +/- 12.8 months, 23 patients (34.3%) died due to causes related to R equi infection and 6 other patients showed evidence of progression of the infection. The absence of highly active antiretroviral therapy (HAART) was independently associated with mortality related to R equi infection (relative risk, 53.4; 95% confidence interval, 1.7 to 1,699). Survival of patients treated with HAART was much higher than that of patients who did not receive this therapy.

CONCLUSIONS

Infection by R equi is an infrequent, opportunistic complication of HIV infection and occurs during advanced stages of immunodepression. In these patients, it leads to a severe illness that usually causes a bacteremic, cavitary pneumonia, although HAART can improve the prognosis.