High-Dose Isoniazid Lacks EARLY Bactericidal Activity Against Isoniazid-resistant Tuberculosis Mediated by katG Mutations: A Randomized, Phase 2 Clinical Trial

RATIONALE

Observational studies suggest that high-dose isoniazid may be efficacious in treating multidrug-resistant tuberculosis (MDR-TB). However, its activity against Mycobacterium tuberculosis (M.tb) with katG mutations (which typically confer high-level resistance) is not established.

OBJECTIVE

To characterize early bactericidal activity (EBA) of high-dose isoniazid in patients with tuberculosis caused by katG-mutated M.tb.

METHODS

A5312 was a Phase 2A randomized, open-label trial. Participants with tuberculosis caused by katG-mutated M.tb were randomized to receive 15 or 20 mg/kg isoniazid daily for 7 days. Daily sputum samples were collected for quantitative culture. Intensive PK sampling was performed on day 6. Data were pooled across all A5312 participants for analysis (drug-sensitive, inhA-mutated, and katG-mutated M.tb). EBA was determined using nonlinear mixed-effects modelling.

RESULTS

Of 80 treated participants, 21 had katG-mutated M.tb. Isoniazid PK was best described by a two-compartment model with an effect of NAT2 acetylator phenotype on clearance. Model-derived Cmax and AUC in the 15 and 20 mg/kg groups were 15.0 and 22.1 mg/L and 57.6 and 76.8 mg∙h/L, respectively. Isoniazid bacterial kill was described using an effect compartment and a sigmoidal Emax relationship. Isoniazid potency against katG-mutated M.tb was approximately 10-fold lower than against inhA-mutated M.tb. The highest dose (20 mg/kg) did not demonstrate measurable EBA, except in a subset of slow NAT2 acetylators (who experienced the highest concentrations). There were no grade 3 or higher drug-related adverse events.

CONCLUSIONS

This study found negligible bactericidal activity of high-dose isoniazid (15-20 mg/kg) in the majority of participants with tuberculosis caused by katG-mutated M.tb. Clinical trial registration available at www.

CLINICALTRIALS

gov, ID: NCT01936831.

A Semi-Mechanistic Model of the Bactericidal Activity of High-Dose Isoniazid Against Multi-Drug-Resistant Tuberculosis: Results from a Randomized Clinical Trial

RATIONALE

There is accumulating evidence that higher-than-standard doses of isoniazid are effective against low-to-intermediate-level isoniazid-resistant strains of Mycobacterium tuberculosis, but the optimal dose remains unknown.

OBJECTIVE

Characterizing the association between isoniazid pharmacokinetics (standard or high-dose) and early bactericidal activity against M. tuberculosis (drug-sensitive and inhA-mutated) and N-acetyltransferase 2 status.

METHODS

ACTG A5312/INHindsight is 7-day early bactericidal activity study with isoniazid at normal dose (5 mg/kg) for patients with drug-sensitive bacteria and 5, 10, and 15 mg/kg doses for patients with inhA mutants. Participants with pulmonary TB received daily isoniazid monotherapy and collected sputum daily. Colony-forming units (CFU) on solid culture and time-to-positivity (TTP) in liquid culture were jointly analyzed using nonlinear mixed-effects modeling.

RESULTS

Fifty-nine adults were included in this analysis. Decline in sputum CFU was described by a one-compartment model, while an exponential bacterial growth model was used to interpret TTP data. The model found bacterial kill is modulated by isoniazid concentration using an effect compartment and a sigmoidal Emax relationship. The model predicted lower potency but similar maximum-kill of isoniazid against inhA-mutated isolates compared to drug-sensitive. Based on simulations from the PK/PD model, to achieve a drop in bacterial load comparable to 5mg/kg against drug-sensitive TB, 10- and 15-mg/kg doses are necessary against inhA-mutated isolates in slow and intermediate N-acetyltransferase 2 acetylators, respectively. Fast acetylators underperformed even at 15 mg/kg.

CONCLUSIONS

Dosing of isoniazid based on N-acetyltransferase 2 acetylator status may help patients attain effective exposures against inhA-mutated isolates while mitigating toxicity risks associated with higher doses. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT01936831.

QT effects of bedaquiline, delamanid, or both in patients with rifampicin-resistant tuberculosis: a phase 2, open-label, randomised, controlled trial

BACKGROUND

Bedaquiline and delamanid are the first drugs of new classes registered for tuberculosis treatment in 40 years. Each can prolong the QTc interval, with maximum effects occurring weeks after drug initiation. The cardiac safety and microbiological activity of these drugs when co-administered are not well-established. Our aim was to characterise the effects of bedaquiline, delamanid, or both on the QTc interval, longitudinally over 6 months of multidrug treatment, among patients with multidrug-resistant or rifampicin-resistant tuberculosis taking multidrug background therapy.

METHODS

ACTG A5343 is a phase 2, open-label, randomised, controlled trial in which adults with multidrug-resistant or rifampicin-resistant tuberculosis receiving multidrug background treatment were randomly assigned 1:1:1 by centrally, computer-generated randomisation, by means of permuted blocks to receive bedaquiline, delamanid, or both for 24 weeks. Participants were enrolled at TASK in Cape Town and the South African Tuberculosis Vaccine Initiative in Worcester, both in South Africa, and Hospital Maria Auxiliadora in Peru. Individuals with QTc greater than 450 ms were excluded. HIV-positive participants received dolutegravir-based antiretroviral therapy. Clofazimine was disallowed, and levofloxacin replaced moxifloxacin. ECG in triplicate and sputum cultures were done fortnightly. The primary endpoint was mean QTcF change from baseline (averaged over weeks 8-24); cumulative culture conversation at week 8-24 was an exploratory endpoint. Analyses included all participants who initiated study tuberculosis treatment (modified intention-to-treat population). This trial is registered with ClinicalTrials.gov, NCT02583048 and is ongoing.

FINDINGS

Between Aug 26, 2016 and July 13, 2018, of 174 screened, 84 participants (28 in each treatment group, and 31 in total with HIV) were enrolled. Two participants did not initiate study treatment (one in the delamanid group withdrew consent and one in the bedaquiline plus delamanid group) did not meet the eligibility criterion). Mean change in QTc from baseline was 12·3 ms (95% CI 7·8-16·7; bedaquiline), 8·6 ms (4·0-13·1; delamanid), and 20·7 ms (16·1-25·3) (bedaquiline plus delamanid). There were no grade 3 or 4 adverse QTc prolongation events and no deaths during study treatment. Cumulative culture conversion by week 8 was 21 (88%) of 24 (95% CI 71-97; bedaquiline), 20 (83%) of 24 (65-95; delamanid), and 19 (95%) of 20 (79-100; bedaquiline plus delamanid) and was 92% (77-99) for bedaquiline, 91% (76-99), for delamanid, and 95% (79-100) for bedaquiline plus delamanid at 24 weeks.

INTERPRETATION

Combining bedaquiline and delamanid has a modest, no more than additive, effect on the QTc interval, and initial microbiology data are encouraging. This study provides supportive evidence for use of these agents together in patients with multidrug-resistant or rifampicin-resistant tuberculosis with normal baseline QTc values.

FUNDING

Division of AIDS, National Institutes of Health.

Dysregulation of the Immune Environment in the Airways During HIV Infection

HIV-1 increases susceptibility to pulmonary infection and disease, suggesting pathogenesis in the lung. However, the lung immune environment during HIV infection remains poorly characterized. This study examined T cell activation and the cytokine milieu in paired bronchoalveolar lavage (BAL) and blood from 36 HIV-uninfected and 32 HIV-infected participants. Concentrations of 27 cytokines were measured by Luminex, and T cells were phenotyped by flow cytometry. Blood and BAL had distinct cytokine profiles (p=0.001). In plasma, concentrations of inflammatory cytokines like IFN-γ (p=0.004) and TNF-α (p=0.004) were elevated during HIV infection, as expected. Conversely, BAL cytokine concentrations were similar in HIV-infected and uninfected individuals, despite high BAL viral loads (VL; median 48,000 copies/ml epithelial lining fluid). HIV-infected individuals had greater numbers of T cells in BAL compared to uninfected individuals (p=0.007); and BAL VL positively associated with CD4+ and CD8+ T cell numbers (p=0.006 and p=0.0002, respectively) and CXCL10 concentrations (p=0.02). BAL T cells were highly activated in HIV-infected individuals, with nearly 2-3 fold greater frequencies of CD4+CD38+ (1.8-fold; p=0.007), CD4+CD38+HLA-DR+ (1.9-fold; p=0.0006), CD8+CD38+ (2.8-fold; p=0.0006), CD8+HLA-DR+ (2-fold; p=0.022) and CD8+CD38+HLA-DR+ (3.6-fold; p<0.0001) cells compared to HIV-uninfected individuals. Overall, this study demonstrates a clear disruption of the pulmonary immune environment during HIV infection, with readily detectable virus and activated T lymphocytes, which may be driven to accumulate by local chemokines.

Early Bactericidal Activity of Different Isoniazid Doses for Drug-Resistant Tuberculosis (INHindsight): A Randomized, Open-Label Clinical Trial

Rationale: High-dose isoniazid is recommended in short-course regimens for multidrug-resistant tuberculosis (TB). The optimal dose of isoniazid and its individual contribution to efficacy against TB strains with inhA or katG mutations are unknown.Objectives: To define the optimal dose of isoniazid for patients with isoniazid-resistant TB mediated by inhA mutations.Methods: AIDS Clinical Trials Group A5312 is a phase 2A, open-label trial in which individuals with smear-positive pulmonary TB with isoniazid resistance mediated by an inhA mutation were randomized to receive isoniazid 5, 10, or 15 mg/kg daily for 7 days (inhA group), and control subjects with drug-sensitive TB received the standard dose (5 mg/kg/d). Overnight sputum cultures were collected daily. The 7-day early bactericidal activity (EBA) of isoniazid was estimated as the average daily change in log10 cfu on solid media (EBAcfu0-7) or as time to positivity (TTP) in liquid media in hours (EBATTP0-7) using nonlinear mixed-effects models.Measurements and Main Results: Fifty-nine participants (88% with cavitary disease, 20% HIV-positive, 16 with isoniazid-sensitive TB, and 43 with isoniazid-monoresistant or multidrug-resistant TB) were enrolled at one site in South Africa. The mean EBAcfu0-7 at doses of 5, 10, and 15 mg/kg in the inhA group was 0.07, 0.17, and 0.22 log10 cfu/ml/d, respectively, and 0.16 log10 cfu/ml/d in control subjects. EBATTP0-7 patterns were similar. There were no drug-related grade ≥3 adverse events.Conclusions: Isoniazid 10-15 mg/kg daily had activity against TB strains with inhA mutations similar to that of 5 mg/kg against drug-sensitive strains. The activity of high-dose isoniazid against strains with katG mutations will be explored next.Clinical trial registered with www.clinicaltrials.gov (NCT01936831).

Effect of HIV on the Frequency and Number of Mycobacterium tuberculosis-Specific CD4+ T Cells in Blood and Airways During Latent M. tuberculosis Infection

Human immunodeficiency virus type 1 (HIV) infection substantially increases the risk of developing tuberculosis. There is extensive depletion of Mycobacterium tuberculosis-specific CD4+ T cells in blood during early HIV infection, but little is known about responses in the lungs at this stage. Given that mucosal organs are a principal target for HIV-mediated CD4+ T-cell destruction, we investigated M. tuberculosis-specific responses in bronchoalveolar lavage (BAL) from persons with latent M. tuberculosis infection and untreated HIV coinfection with preserved CD4+ T-cell counts. M. tuberculosis-specific CD4+ T-cell cytokine (interferon γ, tumor necrosis factor α, and interleukin 2) responses were discordant in frequency and function between BAL and blood. Responses in BAL were 15-fold lower in HIV-infected persons as compared to uninfected persons (P = .048), whereas blood responses were 2-fold lower (P = .006). However, an increase in T cells in the airways in HIV-infected persons resulted in the overall number of M. tuberculosis-specific CD4+ T cells in BAL being similar. Our study highlights the important insights gained from studying M. tuberculosis immunity at the site of disease during HIV infection.

An optimized background regimen design to evaluate the contribution of levofloxacin to multidrug-resistant tuberculosis treatment regimens: study protocol for a randomized controlled trial

Background

Current guidelines for treatment of multidrug-resistant tuberculosis (MDR-TB) are largely based on expert opinion and observational data. Fluoroquinolones remain an essential part of MDR-TB treatment, but the optimal dose of fluoroquinolones as part of the regimen has not been defined.

Methods/design

We designed a randomized, blinded, phase II trial in MDR-TB patients comparing across levofloxacin doses of 11, 14, 17 and 20 mg/kg/day, all within an optimized background regimen. We assess pharmacokinetics, efficacy, safety and tolerability of regimens containing each of these doses. The primary efficacy outcome is time to culture conversion over the first 6 months of treatment. The study aims to determine the area under the curve (AUC) of the levofloxacin serum concentration in the 24 hours after dosing divided by the minimal inhibitory concentration of the patient’s Mycobacterium tuberculosis isolate that inhibits > 90% of organisms (AUC/MIC) that maximizes efficacy and the AUC that maximizes safety and tolerability in the context of an MDR-TB treatment regimen.

Discussion

Fluoroquinolones are an integral part of recommended MDR-TB regimens. Little is known about how to optimize dosing for efficacy while maintaining acceptable toxicity. This study will provide evidence to support revised dosing guidelines for the use of levofloxacin as part of combination regimens for treatment of MDR-TB. The novel methodology can be adapted to elucidate the effect of other single agents in multidrug antibiotic treatment regimens.

Trial registration

ClinicalTrials.gov, NCT01918397. Registered on 5 August 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2292-x) contains supplementary material, which is available to authorized users.

The utility of ultrasound-guided thoracentesis and pleural biopsy in undiagnosed pleural exudates

We assessed the utility of ultrasound to guide the selection of closed pleural biopsy technique and site and to assess the respective contributions of repeat thoracentesis and closed pleural biopsy in 100 consecutive patients with undiagnosed pleural exudates. Thoracentesis was more likely to be diagnostic in TB than malignancy (77.8% vs 31.0%, p<0.001). The addition of ultrasound-guided biopsy increased the combined yield for all diagnoses from 48.0% to 90.0% (p<0.001), for malignancy from 31.0% to 89.7% (p<0.001) and for TB from 77.8% to 88.9% (p=0.688). Our findings suggest that this minimally invasive approach has a high diagnostic yield.

Efficiency and safety of the combination of moxifloxacin, pretomanid (PA-824), and pyrazinamide during the first 8 weeks of antituberculosis treatment: a phase 2b, open-label, partly randomised trial in patients with drug-susceptible or drug-resistant pulmonary tuberculosis

BACKGROUND

New antituberculosis regimens are urgently needed to shorten tuberculosis treatment. Following on from favourable assessment in a 2 week study, we investigated a novel regimen for efficacy and safety in drug-susceptible and multidrug-resistant (MDR) tuberculosis during the first 8 weeks of treatment.

METHODS

We did this phase 2b study of bactericidal activity--defined as the decrease in colony forming units (CFUs) of Mycobacterium tuberculosis in the sputum of patients with microscopy smear-positive pulmonary tuberculosis-at eight sites in South Africa and Tanzania. We enrolled treatment-naive patients with drug-susceptible, pulmonary tuberculosis, who were randomly assigned by computer-generated sequences to receive either 8 weeks of moxifloxacin, 100 mg pretomanid (formerly known as PA-824), and pyrazinamide (MPa100Z regimen); moxifloxacin, 200 mg pretomanid, and pyrazinamide (MPa200Z regimen); or the current standard care for drug-susceptible pulmonary tuberculosis, isoniazid, rifampicin, PZA, and ethambutol (HRZE regimen). A group of patients with MDR tuberculosis received MPa200Z (DRMPa200Z group). The primary outcome was bactericidal activity measured by the mean daily rate of reduction in M tuberculosis CFUs per mL overnight sputum collected once a week, with joint Bayesian non-linear mixed-effects regression modelling. We also assessed safety and tolerability by monitoring adverse events. This study is registered with ClinicalTrials.gov, number NCT01498419.

FINDINGS

Between March 24, 2012, and July 26, 2013 we enrolled 207 patients and randomly assigned them to treatment groups; we assigned 60 patients to the MPa100Z regimen, 62 to the MPa200Z regimen, and 59 to the HRZE regimen. We non-randomly assigned 26 patients with drug-resistant tuberculosis to the DRMPa200Z regimen. In patients with drug-susceptible tuberculosis, the bactericidal activity of MPa200Z (n=54) on days 0-56 (0·155, 95% Bayesian credibility interval 0·133-0·178) was significantly greater than for HRZE (n=54, 0·112, 0·093-0·131). DRMPa200Z (n=9) had bactericidal activity of 0·117 (0·070-0·174). The bactericidal activity on days 7-14 was strongly associated with bactericidal activity on days 7-56. Frequencies of adverse events were similar to standard treatment in all groups. The most common adverse event was hyperuricaemia in 59 (29%) patients (17 [28%] patients in MPa100Z group, 17 [27%] patients in MPa200Z group, 17 [29%] patients. in HRZE group, and 8 [31%] patients in DRMPa200Z group). Other common adverse events were nausea in (14 [23%] patients in MPa100Z group, 8 [13%] patients in MPa200Z group, 7 [12%] patients in HRZE group, and 8 [31%] patients in DRMPa200Z group) and vomiting (7 [12%] patients in MPa100Z group, 7 [11%] patients in MPa200Z group, 7 [12%] patients in HRZE group, and 4 [15%] patients in DRMPa200Z group). No on-treatment electrocardiogram occurrences of corrected QT interval more than 500 ms (an indicator of potential of ventricular tachyarrhythmia) were reported. No phenotypic resistance developed to any of the drugs in the regimen.

INTERPRETATION

The combination of moxifloxacin, pretomanid, and pyrazinamide, was safe, well tolerated, and showed superior bactericidal activity in drug-susceptible tuberculosis during 8 weeks of treatment. Results were consistent between drug-susceptible and MDR tuberculosis. This new regimen is ready to enter phase 3 trials in patients with drug-susceptible tuberculosis and MDR-tuberculosis, with the goal of shortening and simplifying treatment.

FUNDING

Global Alliance for TB Drug Development.

Novel drugs against tuberculosis: a clinician's perspective

The United Nations Millennium Development Goal of reversing the global spread of tuberculosis by 2015 has been offset by the rampant re-emergence of drug-resistant tuberculosis, in particular fluoroquinolone-resistant multidrug-resistant and extensively drug-resistant tuberculosis. After decades of quiescence in the development of antituberculosis medications, bedaquiline and delamanid have been conditionally approved for the treatment of drug-resistant tuberculosis, while several other novel compounds (AZD5847, PA-824, SQ109 and sutezolid) have been evaluated in phase II clinical trials. Before novel drugs can find their place in the battle against drug-resistant tuberculosis, linezolid has been compassionately used with success in the treatment of fluoroquinolone-resistant multidrug-resistant tuberculosis. This review largely discusses six novel drugs that have been evaluated in phase II and III clinical trials, with focus on the clinical evidence for efficacy and safety, potential drug interactions, and prospect for using multiple novel drugs in new regimens.

14-day bactericidal activity of PA-824, bedaquiline, pyrazinamide, and moxifloxacin combinations: a randomised trial

BACKGROUND

New drugs, but also shorter, better-tolerated regimens are needed to tackle the high global burden of tuberculosis complicated by drug resistance and retroviral disease. We investigated new multiple-agent combinations over the first 14 days of treatment to assess their suitability for future development.

METHODS

In this prospective, randomised, early bactericidal activity (EBA) study, treatment-naive, drug-susceptible patients with uncomplicated pulmonary tuberculosis were admitted to hospitals in Cape Town, South Africa, between Oct 7, 2010, and Aug 19, 2011. Patients were randomised centrally by computer-generated randomisation sequence to receive bedaquiline, bedaquiline-pyrazinamide, PA-824-pyrazinamide, bedaquiline-PA-824, PA-824-moxifloxacin-pyrazinamide, or unmasked standard antituberculosis treatment as positive control. The primary outcome was the 14-day EBA assessed in a central laboratory from the daily fall in colony forming units (CFU) of M tuberculosis per mL of sputum in daily overnight sputum collections. Bilinear regression curves were fitted for each group separately and groups compared with ANOVA for ranks, followed by pair-wise comparisons adjusted for multiplicity. Clinical staff were partially masked but laboratory personnel were fully masked. This study is registered, NCT01215851.

FINDINGS

The mean 14-day EBA of PA-824-moxifloxacin-pyrazinamide (n=13; 0·233 [SD 0·128]) was significantly higher than that of bedaquiline (14; 0·061 [0·068]), bedaquiline-pyrazinamide (15; 0·131 [0·102]), bedaquiline-PA-824 (14; 0·114 [0·050]), but not PA-824-pyrazinamide (14; 0·154 [0·040]), and comparable with that of standard treatment (ten; 0·140 [0·094]). Treatments were well tolerated and appeared safe. One patient on PA-824-moxifloxacin-pyrazinamide was withdrawn because of corrected QT interval changes exceeding criteria prespecified in the protocol.

INTERPRETATION

PA-824-moxifloxacin-pyrazinamide is potentially suitable for treating drug-sensitive and multidrug-resistant tuberculosis. Multiagent EBA studies can contribute to reducing the time needed to develop new antituberculosis regimens.

FUNDING

The Global Alliance for TB Drug Development (TB Alliance).

From magic mountain to table mountain

Prior to the introduction of chemotherapy, tuberculosis management relied upon aerotherapy, heliotherapy and good nutrition. This "treatment", exemplified by the regimen applied in Swiss and other European mountain resorts, is described by Thomas Mann in the book "The Magic Mountain". Tuberculosis chemotherapy began in 1944 with the introduction of streptomycin and para-amino-salicylic acid, later augmented by isoniazid. Early experience taught physicians that treatment must be given with multiple drugs to prevent emergence of resistance and that prolonged treatment adherence for 18-24 months was needed for a permanent cure of tuberculosis. Between 1970 and 1980 rifampicin was introduced and with pyrazinamide it made "short-course" treatment possible. For 30 years, a 6-month directly observed treatment short-course (DOTS) based on the three compounds isoniazid, rifampicin and pyrazinamide was the foundation of tuberculosis control strategies world-wide, and in recent years this was supplemented with ethambutol in view of increasing rates of isoniazid resistance. However, even 6 months of treatment is too long to easily ensure the compliance necessary to permanently cure tuberculosis. The recent spread of the HIV/AIDS epidemic has placed tuberculosis programmes under severe pressure and is accompanied by an increase in drug-resistance making tuberculosis virtually untreatable in some instances. In 2004 the first of a new generation of anti-tuberculosis drugs entered clinical evaluation. A series of clinical trials, often conducted at sites in Cape Town, South Africa, has shown them to be efficacious and hold promise of being able to shorten tuberculosis treatment and treat drug-resistant tuberculosis. Development and assessment of these drugs is ongoing but there is renewed hope that these new drugs and regimens will assist in finally conquering tuberculosis, preventing a return to Magic Mountain where sunshine and fresh air was all that could be offered to patients.

Blood loss during flexible bronchoscopy: a prospective observational study

BACKGROUND

Haemorrhage remains a complication of flexible bronchoscopy.

OBJECTIVES

We aimed to measure the actual blood loss in patients at low risk of bleeding and to assess its association with the underlying pulmonary pathology, superior vena cava (SVC) syndrome, procedure(s) performed and laboratory values.

METHODS

We screened all patients scheduled for flexible bronchoscopy and enrolled 234 subjects over 18 months. Subjects with a history of haemorrhagic tendency, platelets <20 × 10(3)/µl, a history of anti-coagulation or anti-platelet therapy and a history or clinical evidence of liver failure were excluded. Blood loss during the procedure was measured from aspirated secretions with a haemoglobin detector and categorised into minimal (<5 ml), mild (5-20 ml), moderate (20-100 ml) and severe bleeding (>100 ml).

RESULTS

Overall, 210 subjects had minimal, 19 had mild and 5 had moderate bleeding. No subject experienced severe blood loss. Patients with SVC syndrome had the highest mean blood loss (6.0 ml) when compared to bronchogenic carcinoma without SVC syndrome (p = 0.033) and other diagnosis (p = 0.026). The blood loss with trans-bronchial needle aspiration (TBNA, mean 3.4 ml) was significantly less than with TBNA combined with endobronchial or transbronchial biopsy (mean 5.0 ml, p < 0.001). Anaemia, a platelet count of 25-155 × 10(3)/µl and an international normalized ratio of >1.3 were not associated with an increased risk of bleeding.

CONCLUSIONS

We found no severe bleeding in this cohort preselected to have a low clinical risk of bleeding. Moreover, our data suggest that clinical screening and a platelet count ≥20 × 10(3)/µl alone may be sufficient to identify low-risk patients.

The yield of different pleural fluid volumes for Mycobacterium tuberculosis culture

We prospectively compared the culture yields of two pleural fluid volumes (5 and 100 ml) inoculated in liquid culture medium in 77 patients of whom 58 (75.3%) were diagnosed with pleural tuberculosis. The overall fluid culture yield was high (60.3% of cases with pleural tuberculosis). The larger volume had a faster time to positivity (329 vs 376 h, p=0.055) but its yield was not significantly higher (53.5% vs 50%; p=0.75). HIV-positive patients were more likely to have positive cultures (78.9% vs 51.5%; p=0.002).

Recent advances in therapeutic bronchoscopy

Therapeutic bronchoscopy has come a long way from removal of foreign bodies to minimally invasive techniques in management of diseases like lung cancer, chronic obstructive pulmonary disease and asthma. This article discusses the exciting new techniques of therapeutic bronchoscopy namely; bronchoscopic lung volume reduction, bronchial thermoplasty, radiofrequency ablation, and use of fiducial markers in external beam irradiation.

Transthoracic Ultrasonography for the Respiratory Physician

Transthoracic ultrasonography is still not utilized to its full potential by respiratory physicians, despite being a well-established and validated imaging modality. It allows for an immediate and mobile assessment that can potentially augment the physical examination of the chest. Ultrasound (US)-assisted procedures can be performed by a single clinician with no sedation and with minimal monitoring, even outside of theatre. The main indications for the use of transthoracic US are: the qualitative and quantitative description of pleu-ral effusions, pleural thickening, diaphragmatic dysfunction and chest-wall and pleural tumours. It may also be used to visualise lung tumours and other parenchymal pulmonary processes provided they abut the pleura. It is at least as sensitive as chest radiographs as far as the detection of a pneumothorax is concerned. It is the ideal tool to assist with thoracocentesis and drainage of effusions. The US-assisted fine-needle aspiration and/or cutting-needle biopsy of extrathoracic lymph nodes, lesions arising from the chest wall, pleura, peripheral lung and mediastinum, are safe and have a high yield in the hands of chest physicians. US may also guide the aspiration and biopsy of diffuse pulmonary infiltrates, consolidations and lung abscesses, provided the chest wall is abutted. Advanced applications of transthoracic US include the diagnosis of pulmonary embolism.

Functional evaluation before lung resection

Lung cancer is the leading cause of cancer-related death worldwide, and lung resection remains the only curative approach. In the Western world, lung cancer is one of the main indications for lung resection, despite only 15% to 25% of all lung cancers being operable at the time of presentation. In most cases of operable lung cancer, a substantial part of functional lung tissue has to be resected, leading to a permanent loss of pulmonary function. Resection in patients with insufficient pulmonary reserves can result in permanent respiratory disability. This article reviews the current standards of preoperative assessment.

[Medical treatment of tuberculosis - update 2011]

Tuberculosis is the second most common cause of death from an infectious disease after HIV/AIDS and the leading cause of death from an infectious disease in HIV-co-infected patients. Currently, drug susceptible TB is treated with a four drug regimen given over a period of two months followed by two drugs for four months. Drug resistant tuberculosis requires more complex and longer treatment with alternative substances. New antituberculosis drugs are currently being developed and investigated and are urgently needed to treat drug susceptible and drug resistant TB.

The Diagnostic Yield and Safety of Ultrasound-Assisted Transthoracic Biopsy of Mediastinal Masses

<i>Background:</i> Ultrasound (US)-assisted transthoracic biopsy offers a less invasive alternative to surgical biopsy in the setting of mediastinal masses. <i>Objectives:</i> The aim of this 1-year prospective study was to assess the diagnostic yield and safety of a novel single-session sequential approach of US-assisted transthoracic fine-needle aspirations (TTFNA) with rapid on-site evaluation (ROSE) followed by cutting needle biopsies (CNB) performed by physicians on patients with anterosuperior mediastinal masses. <i>Methods:</i> US-assisted TTFNA with ROSE was performed on 45 consecutive patients (49.5 ± 27.7 years, 24 males), immediately followed by CNB where a provisional diagnosis of epithelial carcinoma or tuberculosis could not be established, provided a safety range could be assured. <i>Results:</i> TTFNA alone was deemed adequate by means of ROSE in 27 (60%) patients. CNB could be performed in 17 of the remaining 18. The on-site diagnosis corresponded to the final diagnosis in 26/45 (57.8%). An accurate cytological diagnosis was made in 33 (73.3%), and was more likely to be diagnostic in epithelial carcinoma and tuberculosis (28/30) than all other pathologies (5/15, p < 0.001). CNB yielded a diagnosis in 15/17 (88.2%). Overall, 42/45 patients were diagnosed by the single-session approach (93.3%). The final diagnoses included 41 neoplasms, with small cell lung cancer (n = 13) the commonest diagnosis. We observed no pneumothorax or major haemorrhage. <i>Conclusions:</i> A single-session sequential approach of US-assisted TTFNA with ROSE followed by CNB, where indicated, has a high diagnostic yield for anterosuperior mediastinal masses, is safe and offers an alternative to surgical biopsy.

DYRK1 is a co-activator of FKHR (FOXO1a)-dependent glucose-6-phosphatase gene expression

Expression of glucose-6-phosphatase (G6Pase), one of the rate-limiting enzymes of hepatic gluconeogenesis, has recently been shown to be transactivated by the transcription factor FKHR. One of the proteins known to directly interact with FKHR is the nuclear protein kinase DYRK1A. In order to study the effects of DYRK1A on G6Pase gene expression, we generated a H4IIEC3 rat hepatoma cell line stably expressing DYRK1A by retroviral infection. Overexpression of DYRK1A increased the expression of G6Pase about threefold, as determined by Northern blotting. In transiently transfected HepG2 cells, co-expression of DYRK1A and a G6Pase promoter construct increased G6Pase promoter activity about twofold. This effect of DYRK1A was independent of its kinase activity, since a kinase-dead DYRK1A mutant as well as a point mutant of the phosphorylation site of DYRK1A in FKHR (Ser329Ala) failed to affect the effect of DYRK1A on the G6Pase expression. The effect of DYRK on the G6Pase promoter activity was produced by the isoforms DYRK1A and DYRK1B, which are localized in the nucleus, but not by DYRK2. Mutations of the FKHR-binding sites in the G6Pase promoter markedly reduced the effect of DYRK1 on the G6Pase promoter activity. In summary, the data suggest that DYRK1 is a specific co-activator of FKHR, independent of its kinase activity.