Direct antivirals working against the novel coronavirus: azithromycin (DAWn-AZITHRO), a randomized, multicenter, open-label, adaptive, proof-of-concept clinical trial of new antivirals working against SARS-CoV-2-azithromycin trial

BACKGROUND

The rapid emergence and the high disease burden of the novel coronavirus SARS-CoV-2 have created a medical need for readily available drugs that can decrease viral replication or blunt the hyperinflammatory state leading to severe COVID-19 disease. Azithromycin is a macrolide antibiotic, known for its immunomodulatory properties. It has shown antiviral effect specifically against SARS-CoV-2 in vitro and acts on cytokine signaling pathways that have been implicated in COVID-19.

METHODS

DAWn-AZITHRO is a randomized, open-label, phase 2 proof-of-concept, multicenter clinical trial, evaluating the safety and efficacy of azithromycin for treating hospitalized patients with COVID-19. It is part of a series of trials testing promising interventions for COVID-19, running in parallel and grouped under the name DAWn-studies. Patients hospitalized on dedicated COVID wards are eligible for study inclusion when they are symptomatic (i.e., clinical or radiological signs) and have been diagnosed with COVID-19 within the last 72 h through PCR (nasopharyngeal swab or bronchoalveolar lavage) or chest CT scan showing typical features of COVID-19 and without alternate diagnosis. Patients are block-randomized (9 patients) with a 2:1 allocation to receive azithromycin plus standard of care versus standard of care alone. Standard of care is mostly supportive, but may comprise hydroxychloroquine, up to the treating physician's discretion and depending on local policy and national health regulations. The treatment group receives azithromycin qd 500 mg during the first 5 consecutive days after inclusion. The trial will include 284 patients and recruits from 15 centers across Belgium. The primary outcome is time from admission (day 0) to life discharge or to sustained clinical improvement, defined as an improvement of two points on the WHO 7-category ordinal scale sustained for at least 3 days.

DISCUSSION

The trial investigates the urgent and still unmet global need for drugs that may impact the disease course of COVID-19. It will either provide support or else justify the discouragement of the current widespread, uncontrolled use of azithromycin in patients with COVID-19. The analogous design of other parallel trials of the DAWN consortium will amplify the chance of identifying successful treatment strategies and allow comparison of treatment effects within an identical clinical context.

TRIAL REGISTRATION

EU Clinical trials register EudraCT Nb 2020-001614-38 . Registered on 22 April 2020.

Early integrated palliative care in chronic heart failure and chronic obstructive pulmonary disease: protocol of a feasibility before-after intervention study

Background

Patients with chronic heart failure (CHF) and patients with chronic obstructive pulmonary disease (COPD) are amenable to integrated palliative care (PC); however, despite the recommendation by various healthcare organizations, these patients have limited access to integrated PC services. In this study, we present the protocol of a feasibility prospective study that aims to explore if an “early integrated PC” intervention can be performed in an acute setting (cardiology and pulmonology wards) and whether it will have an effect on (i) the satisfaction of care and (ii) the quality of life and the level of symptom control of CHF/COPD patients and their informal caregivers.

Methods

A before-after intervention study with three phases, (i) baseline phase where the control group receives standard care, (ii) training phase where the personnel is trained on the application of the intervention, and (iii) intervention phase where the intervention is applied, will be carried out in cardiology and pulmonology wards in the University Hospital Leuven for patients with advanced CHF/COPD and their informal caregivers. Eligible patients (both control and intervention group) and their informal caregivers will be asked to complete the Palliative Outcome Scale, the CANHELP Lite, and the Advance Care Planning Questionnaire at the inclusion moment and 3 months after hospital discharge.

Discussion

The present study will assess the feasibility of carrying out PC-focused studies in acute wards for CHF/COPD patients and draw lessons for the further integration of PC alongside standard treatment. Further, it will measure the quality of life and quality of care of patients and thus shed light on the care needs of this population. Finally, it will evaluate the potential efficacy of the “early integrated palliative care” by comparing against existing practices.

Trial registration

Current Controlled Trials ISRCTN24796028 (date of registration August 30, 2018).

Endoscopic advanced imaging of the respiratory tract: exploring probe-based confocal laser endomicroscopy in emphysema

: Probe-based confocal laser endomicroscopy (pCLE) was performed in 15 patients with emphysema and 15 healthy subjects to visualise small airways in a direct and dynamic way. Morphometry shows that the median cross-sectional area of the alveolar openings at the level of the alveolar ducts is significantly larger in emphysema (7.2×10⁴ µm²) as compared with healthy subjects (5.2×10⁴ µm²) (p=0.0002). Normalised autofluorescence intensity histograms show a decrease in median autofluorescence intensity (mAFI) in emphysema (p=0.001). mAFI correlates well with Tiffeneau index (r=0.66, p=0.007, 95% CI 0.21 to 0.88). Autofluorescence intensity in emphysema correlates with corresponding data of CT-based quantification. pCLE-based morphometry and autofluorescence intensity analysis in emphysema is able to detect regional changes inside the 'quiet zone'.

TRIAL REGISTRATION NUMBER

Results, NCT01204970.

COPD awareness survey: do Belgian pulmonary physicians comply with the GOLD guidelines 2010?

Chronic Obstructive Pulmonary Disease (COPD) is underestimated, underdiagnosed and often under-treated in the general population. A survey of 17 structured questions, delivered to all Belgian pulmonary physicians (PPs) (116 responses), evaluated diagnosis and treatment strategies in accordance with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines 2010 and assessed opinions about the importance of diurnal variation of COPD symptoms. All COPD diagnoses (37% new cases) were spirometry confirmed. Main diagnostic parameters were symptoms (99%), external risk factors (99%), clinical examination (97%), exacerbations (96%) and patient mobility (96%). FEV1 (forced expiratory volume in 1s) (97%) or FEV1/FVC (ratio of FEV1 to forced vital capacity) (93%) were used most to assess diagnosis and severity. The 3 most important therapeutic objectives were symptom relief, preventing exacerbations, and improving quality of life; if these were not reached, the preferred strategy (60% of PPs) was adding another medication. Treatment strategies varied with COPD stage: short-acting beta2-agonists (90%) and short-acting anti-cholinergics (59%) were used for GOLD I disease, whereas for higher stages long-acting beta2-agonists (36-48%) and long-acting anti-cholinergics (79%) were given with inhaled corticosteroids (21-67%). Symptoms were perceived to vary throughout the day, affecting quality of life (97%) and mobility (89%). In particular, respiratory symptoms were more severe in the morning (51-92%), leading PPs to adapt treatment (69%). This survey demonstrated that management of COPD by PPs in Belgium is generally in line with the GOLD guidelines 2010 and that they perceive morning symptoms as being frequent and having an impact on patient's life.

Quality and reproducibility of spirometry in COPD patients in a randomized trial (UPLIFT®)

BACKGROUND

This study explores spirometry quality and reproducibility in the Understanding Potential Long-term Impacts on Function with Tiotropium (UPLIFT(®)) trial.

METHODS

Four-year, randomized, double-blind, placebo-controlled, multicenter trial in 5993 patients with chronic obstructive pulmonary disease. Within-test variability of pre- and post-bronchodilator forced expiratory volume in 1 s (FEV(1)) was compared across study visits. Between-test variability of best pre- or post-FEV(1) values between two visits 6 months apart was compared at the start, middle and end of the trial.

RESULTS

Three or more acceptable maneuvers were obtained in 93% of visits. Within-test variability of pre- and post-FEV(1) (mean standard deviation: 0.092 and 0.098 L) decreased during the trial. Between-test variability also decreased: pre-FEV(1) (visit 3-5 = 0.141 ± 0.138 L; visit 9-11 = 0.129 ± 0.121 L; visit 17-19 = 0.121 ± 0.122 L); post-FEV(1) (0.139 ± 0.140, 0.126 ± 0.123, 0.121 ± 0.122 L, respectively), and was dependent on age, sex, smoking status and disease stage, but not on bronchodilator response or study treatment.

CONCLUSION

Spirometry quality in UPLIFT(®) was good and improved during the trial. Between-test variability across patient subgroups suggests that relevant cut-offs for individual disease monitoring are difficult to establish.

TRIAL REGISTRATION NUMBER

NCT00144339.

The TERT-CLPTM1L locus for lung cancer predisposes to bronchial obstruction and emphysema

Clinical studies suggest that bronchial obstruction and emphysema increase susceptibility to lung cancer. We assessed the possibility of a common genetic origin and investigated whether the lung cancer susceptibility locus on chromosome 5p15.33 increases the risk for bronchial obstruction and emphysema. Three variants in the 5p15.33 locus encompassing the TERT and CLPTM1L genes were genotyped in 777 heavy smokers and 212 lung cancer patients. Participants underwent pulmonary function tests and computed tomography of the chest, and completed questionnaires assessing smoking behaviour. The rs31489 C-allele correlated with reduced forced expiratory volume in 1 s (p=0.006). Homozygous carriers of the rs31489 C-allele exhibited increased susceptibility to bronchial obstruction (OR 1.82, 95% CI 1.24-2.69; p=0.002). A similar association was observed for diffusing capacity of the lung for carbon monoxide (p=0.004). Consistent with this, CC-carriers had an increased risk of emphysema (OR 2.04, 95% CI 1.41-2.94; p=1.73 × 10(-4)) and displayed greater alveolar destruction. Finally, CC-carriers also had an increased risk for lung cancer (OR 1.90, 95% CI 1.21-2.99; p=0.005), and were more susceptible to developing both lung cancer and bronchial obstruction than lung cancer alone (OR 2.11, 95% CI 1.04-4.26; p=0.038). The rs31489 variant on 5p15.33 is associated with bronchial obstruction, presence and severity of emphysema, and lung cancer.

Exercise training and pulmonary rehabilitation: new insights and remaining challenges

Pulmonary rehabilitation is now regarded as an evidence-based treatment for symptomatic patients with chronic obstructive pulmonary disease. It has been shown to enhance exercise tolerance, improve symptoms and health-related quality of life, and reduce exacerbations in patients with recurrent exacerbations. In this article we review the mechanisms through which exercise training results in beneficial effects. We also review three challenges that currently remain: 1) the fine tuning of exercise training and multidisciplinary programmes; 2) the timing of rehabilitation; and 3) efforts to enhance the accessibility and adherence to pulmonary rehabilitation programmes. Further research is needed in order to apply the now well-established principles of pulmonary rehabilitation to unusual patient populations, or patient populations that are unlikely to participate in conventional outpatient programmes.

Mucoactive therapy in COPD

It has been shown that mucus hypersecretion is associated with greater susceptibility for chronic obstructive pulmonary disease (COPD), excess forced expiratory volume in 1 s decline, hospitalisations and excess mortality. The effects of mucoactive drugs on outcomes have been reviewed in several meta-analyses, the largest one including 26 studies. 21 studies were performed in patients with chronic bronchitis and five in patients with COPD. The majority of these trials were performed with N-acetylcysteine (n = 13) and carbocysteine (n = 3). Overall, there was a significant reduction in exacerbations (0.05 per patient per month) and the number of days with disability (0.56 days per patient per month). Mucolytics were well tolerated and the number of adverse events was lower than with placebo (odds ratio 0.78). In the largest and best designed study with N-acetylcysteine in 523 patients with COPD, the reduction in exacerbations was only observed in patients not taking inhaled corticosteroids. In addition, a 374 mL reduction in functional residual capacity was found. A recent large study (n = 709) with high-dose carbocysteine (1,500 mg·day⁻¹) demonstrated a significant effect on exacerbations (25% reduction) and also reported an improvement in health-related quality of life (-4.06 units in St George's Respiratory Questionnaire). It is unclear what the mechanisms underlying these effects may be and which phenotypes benefit from this treatment. On the basis of this evidence mucoactive drugs may deserve consideration in the long-term treatment of COPD.

Contributing to shipping container security: can passive sensors bring a solution?

Illicit trafficking of fissionable material in container cargoes is recognized as a potential weakness in Nuclear Security. Triggered by the attacks of 11 September 2001, measures were undertaken to enhance maritime security in extension to the Safety Of Life At Sea Convention and in line with the US Container Security Initiatives. Effective detection techniques are needed that allow the inspector to intercept illicit trafficking of nuclear weapons components or components of other nuclear explosive devices. Many security measures focus on active interrogation of the container content by X-ray scan, which might be extended with the newly developed tagged neutron inspection system. Both active interrogation techniques can, with the current huge volume of container traffic, only be applied to a limited number of selected containers. The question arises whether a passive detection technique can offer an alternative solution. This study investigates if containers equipped with a small passive detector will register during transport the neutron irradiation by fissionable material such as plutonium in a measurable way. In practice, 4/5 of the containers are about 1/8 filled with hydrogenous material and undergo a typical 2 months route. For this reference case, it was found that the most compatible passive detector would be an activation foil of iridium. Monte-Carlo simulations showed that for the reference case the activity of a 250 microm thin foil with 6 cm(2) cross-section would register 1.2 Bq when it is irradiated by a significant quantity of Reactor-Grade PuO(2). However this activity drops with almost two orders of magnitude for other fillings and other isotopic compositions and forms of the Pu-source. The procedure of selecting the target material for Pu detection is detailed with the theoretical methods, in order to be useful for other applications. Moreover the value of such additional passive sensors for securing maritime container transport is situated within the global framework of the First, Second and Third Line of Defense against illicit trafficking.

Drug impurity profiling: Method optimization on dissimilar chromatographic systems: Part I: pH optimization of the aqueous phase

The use of dissimilar chromatographic systems in drug impurity profiling can be very advantageous. Screening a new-drug impurity mixture on those systems not only enhances the chance that all impurities are revealed, but also allows choosing a suited system for further method development. In this paper several strategies were evaluated to predict the optimal pH (of the buffer used in the mobile phase) from the screening results. Four or five dissimilar stationary phases were screened at four pH values (between 2.5 and 9.4), in order to obtain maximal information about the composition of the sample and to select one column for the subsequent optimization. Different linear models (straight lines, 2nd and 3rd degree polynomials) based on these experiments were tested for their ability to predict the retention times (t(R)) of the impurities at intermediate pH values. The predicted t(R) values were then used to calculate minimal resolutions and eventually to select an optimal pH at which the highest minimal resolution is predicted. None of the applied models is accurate enough to predict correctly which peaks are worst separated at the indicated optimal pH. However, the best strategy (applying a second degree polynomial describing the t(R) measured at 3 consecutive screening pH values) did succeed in indicating an optimal pH at which a good separation of the impurities is obtained. Unfortunately, the resulting separation quality is not or only slightly better than the best separation obtained during screening. Therefore, it can be concluded that the most (time-) efficient approach to develop an impurity profile of a new drug is to screen it on four or five dissimilar columns at four different pH values and to retain the best screening conditions (without making predictions for intermediate conditions) for further optimization of the organic modifier composition of the mobile phase, and occasionally the temperature and the gradient. This is at least the case when the profiles have a complexity similar to those studied.

The use of metabolising systems for in vitro testing of endocrine disruptors

Legislation and prospective legislative proposals in for instance the USA, Europe, and Japan require, or may require that chemicals are tested for their ability to disrupt the hormonal systems of mammals. Chemicals found to test positive are considered to be endocrine active substances (EAS) and may be putative endocrine disruptors (EDs). To date, there is still little or no experience with incorporating metabolic and toxicokinetic aspects into in vitro tests for EAS. This is a situation in sharp contrast to genotoxicity testing, where in vitro tests are routinely conducted with and without metabolic capacity. Originally prepared for the Organisation of Economic Cooperation and Development (OECD), this detailed review paper reviews why in vitro assays for EAS should incorporate mammalian systems of metabolism and metabolic enzyme systems, and indicates how this could be done. The background to ED testing, the available test methods, and the role of mammalian metabolism in the activation and the inactivation of both endogenous and exogenous steroids are described. The available types of systems are compared, and the potential problems in incorporating systems in in vitro tests for EAS, and how these might be overcome, are discussed. Lastly, some recommendations for future activities are made.

Metabolic syndrome in the elderly: an overview of the evidence

We reviewed the literature concerning the prevalence and correlates of metabolic syndrome (MetS) in older adults and assessed the impact of MetS with regard to life expectancy and comorbidity in the elderly (aged 65 years and over). Using the PubMed database and the Cochrane Library, we found 16 eligible studies, of which 8 were prospective cohort studies, 7 cross-sectional studies, and 1 a case-control study. The World Health Organisation (WHO) and National Cholesterol Education Program (NCEP) are the most popular definitions to describe MetS experienced by the elderly. The prevalence of metabolic syndrome in an elderly population varied from 11% to 43% (median 21%) according to the WHO, and 23% to 55 % (median 31%) according to NCEP. Obesity and hypertension are the most prevalent individual components. MetS in an elderly population is a proven risk factor for cardiovascular (CV) morbidity, especially stroke and coronary heart disease (CHD), and mortality. Preventing and treating MetS would be useful in preventing disability and promoting normal aging. Results from the different studies of elderly population-based cohorts provide support for earlier investigations in middle-aged populations to prevent MetS components. In conclusion, it is possible to say that the results from the different elderly study populations link the presence of the MetS with the development of cardiovascular disease (CVD) and functional disability, and further underscore the importance of recognising and treating its individual components, particularly high blood pressure.

Inspiratory flow rates at different levels of resistance in elderly COPD patients

Dry powder inhalers (DPIs) are increasingly replacing metered dose inhalers in elderly chronic obstructive pulmonary disease (COPD) patients. However, most DPIs are dependent on inspiratory flow, which is compromised by the ageing process itself. Using the in-check dial method, the present study compared peak inspiratory flow (PIF) rates in 26 elderly COPD patients and 14 matched control subjects, at a pre-set resistance level of the Aeroliser, Diskus and Turbuhaler inhalers. It was found that the PIF measured by the in-check method positively correlated with the PIF derived from spirometry, forced vital capacity and maximal inspiratory pressure, while a negative, but significant, correlation was observed with age. PIF derived from spirometry and age were independent variables which determined PIF across the device, whereas the presence or absence of COPD was not related. When comparing elderly COPD patients with matched elderly controls no difference could be found in PIF at the different resistances. However, an important number of patients did not reach the recommended flow rate, especially when using the Turbuhaler (30%). In conclusion, the present study demonstrates that, in elderly patients, the ability to generate sufficient inspiratory flow across a dry powder inhaler is compromised, irrespective of the presence of chronic obstructive pulmonary disease.

Listeria pleuritis 1 week after lung transplantation

Listeria monocytogenes is an important bacterial pathogen in immunocompromised patients, the elderly, pregnant women and transplant patients, but until now it has not been reported in lung transplants. We report the first case of listeriosis in a lung transplant recipient who presented with a pleural effusion 8 days after transplantation. After the introduction of a thorax drain and the administration of intravenous antibiotics during 3 weeks, the patient recovered completely. This case highlights the increased risk for uncommon respiratory infections in lung transplant patients and examines the specific management of listeria pleuritis.

Paralysis due to severe hypokalemia

We report two cases of a patient with paresis/paralysis caused by a severe iatrogenic hypokalemia. In both cases, the extreme muscle weakness disappeared with correction of the electrolyte disturbance. The mechanisms of hypokalemia due to nephrotoxic drugs and treatment of this electrolyte disturbance are discussed.

Genetic variability of the V1 and V2 env domains of SIVcpz-ant and neutralization pattern of plasma viruses in a chimpanzee infected naturally

Specific neutralizing epitope changes have been observed in a chimpanzee infected naturally with SIVcpz, which differ from HIV-1 infecting humans. To characterize further these changes, a longitudinal study of env genomic sequence variation of SIVcpz-ant isolates was undertaken in this animal. The V1 and V2 regions of the env were determined to arise from specific recombination events. To determine whether recombination of the V1 and V2 domains was possibly associated with the emergence of neutralization escape viruses, envelope sequences and gene length polymorphisms from PBMC and plasma viral variants were studied over a 7-year period. PBMCs and plasma-associated infectious virus titers as well as plasma RNA viral loads were monitored longitudinally. The first 5 viruses isolated from the plasma were found to be neutralization escape variants. Sequence analysis of their V1 and the V2 regions indicated that a 20 amino acid stretch of the V1 region had undergone recombination and was also associated with the emergence of isolates eliciting strong neutralization responses. These findings support the hypothesis that recombination of the V1 and V2 regions of the envelope play a role in neutralization escape of SIVcpz in chimpanzees infected naturally. Furthermore, the data confirm that the neutralizing antibody response plays an important role in the decline of plasma infectious virus titers in HIV-1 related SIVcpz nonpathogenic infection.

Genetic analysis of HIV type 2 from Ghana and Guinea-Bissau, West Africa

The phylogenetic variability of part of the long terminal repeat (LTR) region of HIV-2 strains isolated in 1995 from five individuals residing in Bissau, the capital city of Guinea-Bissau, and collected from seven persons from Kumasi, Ghana in 1996-1997, was analyzed. All Guinean samples and all but one Ghanaian sample clustered with HIV-2 subtype A. One Ghanaian sample (14%) was classified as HIV-2 subtype B. This study adds to previous reports on HIV-2 subtype distribution in West Africa indicating local prevalence of HIV-2 subtype B in Ivory Coast and neighboring Ghana.

HIV-1 subtypes and the HIV epidemics in four cities in sub-Saharan Africa

OBJECTIVE

To describe the distribution of HIV-1 subtypes in two cities with high HIV prevalence (Kisumu, Kenya and Ndola, Zambia) and two with relatively low prevalence (Cotonou, Benin and Yaoundé, Cameroon), and to examine whether the differences in prevalence of HIV infection could be due to the predominance within the infected populations of subtypes with differing efficiency of heterosexual transmission.

METHODS

For around 100 randomly selected HIV-positive sera from the general population and 60 from sex workers in each city, the HIV-1 subtype was determined in the envfragment. For between 19 and 52 of the sera from the general population and 20-32 sera from sex workers, the subtype was also determined in the gag fragment.

RESULTS

Over 70% of infections in Cotonou, Yaoundé and Kisumu were with subtype A (by env). However, around one-half of subtype A infections in Cotonou and Yaoundé were found to be the circulating recombinant form CRF02_AG when the gag fragment was also examined. A large number of different HIV strains were found in Yaoundé, including some belonging to group O. Over 20% of infections in Kisumu and around 10% in Yaoundé were with isolated intersubtype recombinant forms. All but a few infections in Ndola were with subtype C and no recombinants were found.

CONCLUSIONS

The pattern of distribution of subtypes that we found does not suggest that differences in circulating subtypes play a major role in explaining the differences in prevalence of HIV-1 infection between the four cities. The emergence and spread of recombinants requires close surveillance to adapt testing strategies if needed, to inform vaccine development and to ascertain their role in the future spread of HIV.

Quantification of growth hormone receptor extra- and intracellular domain gene expression in chicken liver by quantitative competitive RT-PCR

The very sensitive competitive reverse transcription-polymerase chain reaction (RT-PCR) was used to investigate the expression of the extracellular (GHRe) and intracellular (GHRi) parts of the growth hormone receptor (GHR) in the liver tissue of chickens. Two competitors (internal standards), pGHRi MUT and pGHRe MUT, specific to the GHRi and GHRe genes, respectively, were constructed by site-specific mutagenesis. The internal standards defined PCR products of 394 bp for the pGHRi MUT and 330 bp for the GHRe MUT. These were used as competitors to the wild-type GHRi or GHRe which defined PCR products of 382 and 328 bp, respectively. Coamplification, under standardized conditions, of the native RNA in competition with serial dilutions of the mutant RNA in the same PCR reaction followed by enzymatic digestion produced the expected sizes of internal standard cDNA and predicted target cDNA. Expression levels of GHRe and GHRi were determined from standard curves generated. The method was sensitive enough to detect expressions down to picogram levels. Applying this method, the effect of GH and T(3) injection on GHRe and GHRi mRNA expression was determined in the liver of adult female Hisex birds and 1-day-old normal and dwarf chickens. Intravenous GH injection (25 microg/kg body weight) increased plasma levels of GH in Hisex birds after 10 min but rapidly decreased at 60 min followed by an increase in T(3). GH injection significantly increased the expression of the GHRe 60 min after injection but not at 10 min, when the GH level in plasma was high. In the liver of saline-treated dwarf (dw) and nondwarf (Dw) chicks, the level of expression of GHRe was similar in both strains despite disparate levels of basal GH and T(3). However, the level of GHRi was higher in Dw than in dw chicks. Although GH levels increased in both strains after intravenous GH injection (250 microg/kg body wt), the expression of GHRe in both strains was unaffected. However, the mRNA for the GHRi was significantly depressed by injection in the Dw but unaffected in dw chicks. Intravenous injection of T(3) (0.5 and 5 microg/kg body wt) increased plasma levels in both strains but caused depression of GHRi in Dw but not in dw chicks. T(3) injections had no effect on GHRe in either Dw or dw chicks. It is concluded that the expression of the GHRe in adult chickens is GH regulated either directly or indirectly. In contrast, in 1-day-old chicks, GH or T(3) had no effects on the GHRe but regulated the expression of GHRi in Dw chicks, whereas in dwarf chicks both had no effect on GHRe or GHRi expression. It is postulated that GHRe and GHRi gene expression may be regulated by different agonists/antagonists in different strains and depending on the age of the chicken.

Potent broad cross-neutralizing sera inhibit attachment of primary HIV-1 isolates (groups M and O) to peripheral blood mononuclear cells

Gp160-directed antibody-mediated neutralization is thought to function by at least two different mechanisms that impair virus entry into the host cell: inhibition of virus attachment and inhibition of virus-cell membrane fusion. Previously, the neutralization spectra of sera derived from human immunodeficiency virus type 1 (HIV-1) infected patients were determined using 17 primary isolates belonging to HIV-1 group M (env clades A-H) and group O. The sera could be categorized as potent broad cross-neutralizing, limited cross-neutralizing, and nonneutralizing sera. The aim of this study was to examine whether the neutralizing capacity of polyclonal human sera correlates with their capacity to inhibit the attachment of infectious virions to the surface of peripheral blood mononuclear cells. A 100% correlation was found between the broad cross-neutralizing capacity and the ability to inhibit binding of primary isolates belonging to different genetic clades and groups to peripheral blood mononuclear cells. These results may indicate that broad cross-neutralizing antibodies are directed against those conserved regions on gp120 that interact with the cell receptor(s) and that those antibodies can therefore interfere with the binding of virus to the host cell.

Reanalysis of full-length HIV type 1 group M subtype K and sub-subtype F2 with an MS-DOS bootscanning program

Five new complete HIV-1 group M genome sequences have been published (Triques et al., AIDS Res Hum Retroviruses 2000;16:139-151). One of these clustered consistently with subtype F sequences, while two others were identified as representatives of a subcluster within the subtype F clade, called F2, and the two remaining sequences were described as a new subtype K. We reanalyzed these sequences by means of bootscanning and phylogeny, using a newly developed MS-DOS bootscanning program. Although our analysis does not contradict the existence of the new subtype K, it also indicates that in some regions the F2 sequences do not cluster with the F1 clade. This suggests that some fragments in the F2 sequences have an uncertain origin, and care should be taken when F2 sequences are used in analyses.

Study of HIV type 1 gag/env variability in The Gambia, using a multiplex DNA polymerase chain reaction

A multiplex DNA PCR assay was developed for the simultaneous first-round amplification of HIV-1 gag and env fragments for the heteroduplex mobility assay (HMA). This assay was compared with the conventional amplification assay, using DNA extracted from PBMC samples from 30 HIV-1-seropositive individuals from The Gambia, who were enrolled between 1992 and 1997. From 27 of 30 (90%) samples both gag and env HMA fragments were amplified simultaneously. In one sample only the gag HMA fragment could be amplified by multiplex DNA PCR, and in two samples amplification was negative for both gag and env HMA in multiplex as well as the mono-DNA PCR. Of the 28 Gambian isolates subtyped by gag/env HMA or by sequencing and phylogenetic analysis, the majority (19 of 28; 68%) were intersubtype recombinant. Fifteen of 28 (53%) samples were circulating recombinant form (CRF) CRF02.AG variants. Two isolates clustering with the previously documented Gambian isolate GM4 (previously described as an env GC recombinant) are classified as gag A/env J recombinants.

Development of a one-tube multiplex reverse transcriptase-polymerase chain reaction assay for the simultaneous amplification of HIV type 1 group M gag and env heteroduplex mobility assay fragments

The emergence of intersubtype recombinant HIV-1 isolates has made it imperative to analyze different regions of HIV-1 genomes. For this purpose a one-tube multiplex RT-PCR, coamplifying first-round amplicons that allow amplification of gag and env heteroduplex mobility assay (HMA) fragments from different HIV-1 group M isolates, was developed, starting with plasma samples. The multiplex RT-PCR assay is sensitive: 115 of 136 (84.5%) samples were positive for both gag and env, positive amplification of the gag fragment was observed in 130 of 136 (95.6%) samples, while for the env fragment 119 of 136 (87.5%) tested positive. The multiplex RT-PCR in combination with gag and env HMA makes large-scale HIV-1 subtyping fast, simple, and more economical.

Natural residues versus antiretroviral drug-selected mutations in HIV type 1 group O reverse transcriptase and protease related to virological drug failure in vivo

HIV-1 group O viruses were first recognized as a distinct subgroup of HIV-1 with the isolation and characterization in 1990 of a virus (ANT70) from a woman (individual A) and her spouse (individual B), both from Cameroon (De Leys R, et al.: J Virol 1990;64:1207-1216). During the 5-6 years before treatment, individual A remained asymptomatic, with viral RNA levels between 2.5 and 2.8 log10 copies/ml, as measured by a newly developed group O-specific quantitative NASBA-based RNA assay. Individual B developed mild clinical symptoms, with 3.1 to 3.6 log10 copies of viral RNA per milliliter. HIV-1 sequences obtained from both individuals showed pretreatment residues in protease that confer resistance to protease inhibitors in group M viruses (10I, 36I, and 71V). Individual A showed an initial response to AZT, but shortly after addition of ddC and saquinavir, the RNA levels returned to baseline, while subsequent treatment with d4T, 3TC, and indinavir reduced the RNA level to less than 50 copies/ml for the time of follow-up. Individual B showed no response to AZT or ddC monotherapy, and a change to d4T, 3TC, and indinavir had, in contrast to individual A, only a temporary effect. While a multitude of mutations in HIV-1 group O reverse transcriptase (RT) and protease appeared that are associated with drug resistance in group M viruses, the observed T215N mutation in RT and the V15I and V22A mutations in protease have not previously been described and may represent resistance-conferring mutations specific to group O viruses. These results indicate that treatment of HIV-1 group O-infected individuals with antiretroviral drug regimens that include protease inhibitors might lead to rapid selection for resistance-conferring mutations. This probably results from preexisting protease residues contributing to reduced sensitivity of group O viruses to protease inhibitors, as is observed in vitro.

Identification and characterization of sera from HIV-infected individuals with broad cross-neutralizing activity against group M (env clade A-H) and group O primary HIV-1 isolates

A previous study on cross-clade neutralization activity, identified three key isolates, MNlab (envB/gagB; X4 coreceptor), VI525 (envG/gagH, envA/gagA; R5X4) and CA9 (Group O; R5), that allowed discrimination of sera, likely or unlikely to neutralize primary HIV-1 isolates belonging to Group M (env clades A-H) and Group O. The prognostic ability of these three isolates was verified by means of an external validation on a different and larger set of sera. A total of 79 different sera (66 HIV-1, 10 HIV-2, 1 HIV-1+2 and 2 SIV(cpz)) were examined first for their capacity to neutralize the three key isolates, next sera were challenged against 12 other primary HIV-1 isolates of Group M (env A-H) and 2 isolates of Group O. Sera that neutralized all three isolates with an ID(50) titer of > or =1/40, also neutralized the 14 other primary isolates belonging to different genetic groups and clades. Sera that did not neutralize all three isolates did not exert broad cross-neutralizing activity. The neutralizing activity was antibody-mediated because it was absorbed and eluted from a Prot-G column. Competition-neutralization experiments using recombinant gp120 (HIV-1 MNlab) reduced the neutralizing capacity, suggesting that the neutralizing antibodies were directed against the Env protein. Remarkably, the broad cross-neutralization activity was found primarily in African female patients. In conclusion, this study confirms that three isolates are sufficient to allow identification of broad cross-neutralizing sera.

Near full-length genome analysis of HIV type 1 CRF02.AG subtype C and CRF02.AG subtype G recombinants

HIV-1 CRF02.AG strains are prevalent in west and west-central Africa, suggesting a longstanding presence of these subtype A/G recombinants in the global epidemic. Cocirculation of CRF02.AG strains with other group M subtypes may give rise to HIV-1 recombinants constituting a mosaic genome comprising fragments of three different subtypes. We report on the genetic analysis of the near-full-length genomes of such recombinants (VI1035 and VI1197) as well as CRF02.AG strains in Belgian individuals. VI1035 and VI1197 may be the result of successful "second-generation" recombinations of HIV-1 strains CRF02.AG with, respectively, subtype C (VI1035) and G (VI1197) strains in a dually infected individual.