P5000Wnt/b-catenin signalling drives angiotensin II induced cardiac fibrosis via WISP-1

Background

Myocardial infarction (MI) and hypertension lead to myocardial injury, which induces negative remodelling and cardiac fibrosis. Cardiac fibrosis, which involves inflammatory cell infiltration and myofibroblast activation, causes worldwide mortality and morbidity. In response to MI or hypertension induced by prolonged angiotensin II (AngII) exposure, activated myofibroblasts produce extracellular matrix proteins. However, if unchecked, excessive collagen deposition occurs leading to myocardial stiffening, heart failure and arrhythmias.

Purpose

The underlying mechanisms leading to pathological collagen deposition are not fully elucidated. There is debate regarding the involvement of the Wnt signalling pathway and its product Wnt Inducible Signalling pathway protein-1 (WISP-1) in cardiac fibrosis. Therefore, this project aimed to investigate the interaction of AngII and the Wnt/β-catenin signalling pathway in cardiac fibrosis.

Methods

The effect of AngII (100nM) on collagen levels in human cardiac fibroblasts was investigated in vitro (data expressed as fold change from control ± SEM). In vivo experiments (n=6–8) determined the involvement of the Wnt/b-catenin pathway, specifically WISP-1, in response to AngII infusion (500ng/kg/min) for 4 weeks (Apolipoprotein E−/−/WISP-1+/+ vs. ApolipoproteinE−/−/WISP-1−/− mice on a high-fat diet, data expressed as mean positive pixel % ± SEM).

Results

AngII significantly increased collagen type 1 protein levels produced by human cardiac fibroblasts (2.94±0.75 vs 1±0, p<0.05). Inhibition of Wnt/b-catenin signalling with 25nM iCRT14 significantly suppressed AngII-induced collagen levels (0.46±0.07 vs. 1±0, p<0.05). As expected, AngII infusion significantly induced hypertension in all mice. Immunohistochemistry demonstrated type 1 collagen was markedly higher in AngII mice than control mice (1.07±0.27 vs. 0.29±0.06, p<0.05). However, in the absence of WISP-1, AngII did not enhance collagen type 1 levels. Further immunohistochemical analysis of murine hearts demonstrated that AngII infusion caused significant alterations in the Wnt/β-catenin signalling markers AXIN-2 (35±3.9 vs. 10.7±2.6 p<0.05) and PPAR-d (92±1.4 vs. 17.3±4.3 p<0.05). This effect was reduced by WISP-1 deletion. Furthermore, AngII-infusion disrupted N-cadherin junctions (0.55±0.08 vs. 0.29±0.02 p<0.05) suggesting modulation of cell-to-cell contacts and enhanced β-catenin signalling.

Conclusion

This study indicates that AngII enhances cardiac fibrosis via modulation of the Wnt signalling pathway, in part via WISP-1. Further delineation of this interaction may lead to the use of Wnt/β-catenin or WISP-1 inhibitors to suppress myocardial injury induced cardiac fibrosis in post-MI or hypertensive patients.

Acknowledgement/Funding

Elizabeth Blackwell Institute, British Heart Foundation

Sputum smear-positive, culture-negative state during anti-tuberculosis treatment in the MGIT liquid culture era

The sputum smear-positive, culture-negative state poses a challenge for clinicians. Previous studies have shown that most samples with positive smears during the later stages of treatment are culture-negative. Earlier studies generally used solid culture media, which tend to be less sensitive than current liquid culture systems. We examined the smear-positive, culture-negative state in the era of MGIT™ 960™ liquid cultures. We found that the smear-positive, culture-negative state occurred less frequently with MGIT culture, and that the majority of the samples with late positive smears were culture-negative, regardless of media type.

Simulating Transplant Small-for-size Grafts Using Human Liver Monosegments: The Impact of Portal Perfusion Pressure

Small-for-size-liver grafts (SFSG) in adult transplant recipients have elevated risk of graft failure, limiting its application in clinical liver transplantation. Relevant preclinical model of SFSG is lacking. Relevant to deceased-donor split liver transplant and living-donor liver transplant in adult recipients, in this study, we present our initial characterization of SFSG model using monosegments of a discarded human donor liver.

Carotid artery ligation induced intimal thickening and proliferation is unaffected by ageing

Following interventions to treat atherosclerosis, such as coronary artery bypass graft surgery, restenosis occurs in approximately 40% of patients. Identification of proteins regulating intimal thickening could represent targets to prevent restenosis. Our group previously demonstrated that in a murine model of vascular occlusion, Wnt4 protein expression and β-catenin signalling was upregulated which promoted vascular smooth muscle cell (VSMC) proliferation and intimal thickening. In this study, the effect of age on VSMC proliferation, intimal hyperplasia and Wnt4 expression was investigated. In vitro proliferation of VSMCs isolated from young (2 month) or old (18-20 month) C57BL6/J mice was assessed by immunocytochemistry for EdU incorporation. As previously reported, 400 ng/mL recombinant Wnt4 protein increased proliferation of VSMCs from young mice. However, this response was absent in VSMCs from old mice. As our group previously reported reduced intimal hyperplasia in Wnt4+/- mice compared to wildtype controls, we hypothesised that impaired Wnt4 signalling with age may result in reduced neointimal formation. To investigate this, carotid artery ligation was performed in young and old mice and neointimal area was assessed 21 days later. Surprisingly, neointimal area and percentage lumen occlusion were not significantly affected by age. Furthermore, neointimal cell density and proliferation were also unchanged. These data suggest that although Wnt4-mediated proliferation was impaired with age in primary VSMCs, carotid artery ligation induced neointimal formation and proliferation were unchanged in old mice. These results imply that Wnt4-mediated proliferation is unaffected by age in vivo, suggesting that therapeutic Wnt4 inhibition could inhibit restenosis in patients of all ages.

Reader variability and validation of the Timika X-ray score during treatment of pulmonary tuberculosis

SETTING

Chest radiographs (CXRs) are widely used for diagnosing pulmonary TB and assessing response to therapy. The Timika X-ray score has been proposed as a tool for measuring disease severity and predicting treatment outcome.

OBJECTIVE

To evaluate inter- and intra-reader agreement of Timika scores and assess the ability of the score to predict microbiologic outcome at 2 months.

DESIGN

Analytical validation study. Disease severity was measured by two readers using pretreatment radiographs and follow-up films taken at 2, 6 and 12 months after the start of treatment among 110 human immunodeficiency virus negative adults with pulmonary TB. One fourth of the films were reread to assess intra-reader agreement.

RESULTS

The two-component Timika score had high inter- and intra-reader agreement (intraclass correlation (ICC)_inter = 75%, ICC_intra > 0.81). Baseline Timika score was associated with positive month 2 smear (P = 0.0004) and culture status (P = 0.03). The average Timika score declined significantly over the course of successful treatment.

CONCLUSION

The Timika score showed good inter- and intra-reader agreement and a significant association with microbiological outcomes after 2 months of treatment. The results of this study strengthen the evidence supporting the use of the Timika score for measuring disease severity on CXR.

Defining the optimal dose of rifapentine for pulmonary tuberculosis: Exposure-response relations from two phase II clinical trials

Rifapentine is a highly active antituberculosis antibiotic with treatment-shortening potential; however, exposure-response relations and the dose needed for maximal bactericidal activity have not been established. We used pharmacokinetic/pharmacodynamic data from 657 adults with pulmonary tuberculosis participating in treatment trials to compare rifapentine (n = 405) with rifampin (n = 252) as part of intensive-phase therapy. Population pharmacokinetic/pharmacodynamic analyses were performed with nonlinear mixed-effects modeling. Time to stable culture conversion of sputum to negative was determined in cultures obtained over 4 months of therapy. Rifapentine exposures were lower in participants who were coinfected with human immunodeficiency virus, black, male, or fasting when taking drug. Rifapentine exposure, large lung cavity size, and geographic region were independently associated with time to culture conversion in liquid media. Maximal treatment efficacy is likely achieved with rifapentine at 1,200 mg daily. Patients with large lung cavities appear less responsive to treatment, even at high rifapentine doses.

Platinum coat color in red fox (Vulpes vulpes) is caused by a mutation in an autosomal copy of KIT

The red fox (Vulpes vulpes) demonstrates a variety of coat colors including platinum, a common phenotype maintained in farm-bred fox populations. Foxes heterozygous for the platinum allele have a light silver coat and extensive white spotting, whereas homozygosity is embryonic lethal. Two KIT transcripts were identified in skin cDNA from platinum foxes. The long transcript was identical to the KIT transcript of silver foxes, whereas the short transcript, which lacks exon 17, was specific to platinum. The KIT gene has several copies in the fox genome: an autosomal copy on chromosome 2 and additional copies on the B chromosomes. To identify the platinum-specific KIT sequence, the genomes of one platinum and one silver fox were sequenced. A single nucleotide polymorphism (SNP) was identified at the first nucleotide of KIT intron 17 in the platinum fox. In platinum foxes, the A allele of the SNP disrupts the donor splice site and causes exon 17, which is part of a segment that encodes a conserved tyrosine kinase domain, to be skipped. Complete cosegregation of the A allele with the platinum phenotype was confirmed by linkage mapping (LOD 25.59). All genotyped farm-bred platinum foxes from Russia and the US were heterozygous for the SNP (A/G), whereas foxes with different coat colors were homozygous for the G allele. Identification of the platinum mutation suggests that other fox white-spotting phenotypes, which are allelic to platinum, would also be caused by mutations in the KIT gene.

Wnt5a-induced Wnt1-inducible secreted protein-1 suppresses vascular smooth muscle cell apoptosis induced by oxidative stress

OBJECTIVE

Apoptosis of vascular smooth muscle cells (VSMCs) contributes to thinning and rupture of the atherosclerotic plaque fibrous cap and is thereby associated with myocardial infarction. Wnt protein activation of β-catenin regulates numerous genes that are associated with cell survival. We therefore investigated Wnt/β-catenin survival signaling in VSMCs and assessed the presence of this pathway in human atherosclerotic plaques at various stages of the disease process.

APPROACH AND RESULTS

Wnt5a induced β-catenin/T-cell factor signaling and retarded oxidative stress (H₂O₂)-induced apoptosis in mouse aortic VSMCs. Quantification of mRNA levels revealed a >4-fold (P<0.05; n=9) increase in the expression of the Wnt/β-catenin responsive gene, Wnt1-inducible secreted protein-1 (WISP-1), which was dependent on cAMP response element-binding protein and sustained in the presence of H₂O₂. Exogenous WISP-1 significantly reduced H₂O₂-induced apoptosis by 43% (P<0.05; n=3) and was shown using silencing small interfering RNA, to be important for Wnt5a-dependent survival responses to H₂O₂ (P<0.05; n=3). WISP-1 protein levels were significantly lower (≈50%) in unstable atherosclerosis compared with stable plaques (n=11 and n=14).

CONCLUSIONS

These results indicate for the first time that Wnt5a induces β-catenin survival signaling in VSMCs via WISP-1. The deficiency of the novel survival factor, WISP-1 in intimal VSMCs of unstable coronary plaques, suggests that there is altered Wnt/β-catenin/ T-cell factor signaling with progressive atherosclerosis, and restoration of WISP-1 protein might be an effective stabilization factor for vulnerable atherosclerotic plaques.

Emerging regulators of vascular smooth muscle cell function in the development and progression of atherosclerosis

After a period of relative senescence in the field of vascular smooth muscle cell (VSMC) research with particular regards to atherosclerosis, the last few years has witnessed a resurgence, with extensive research re-assessing potential molecular mechanisms and pathways that modulate VSMC behaviour within the atherosclerotic-prone vessel wall and the atherosclerotic plaque itself. Attention has focussed on the pathological contribution of VSMC in plaque calcification; systemic and local mediators such as inflammatory molecules and lipoproteins; autocrine and paracrine regulators which affect cell-cell and cell to matrix contacts alongside cytoskeletal changes. In this brief focused review, recent insights that have been gained into how a myriad of recently identified factors can influence the pathological behaviour of VSMC and their subsequent contribution to atherosclerotic plaque development and progression has been discussed. An overriding theme is the mechanisms involved in the alterations of VSMC function during atherosclerosis.

Relapse more common than reinfection in recurrent tuberculosis 1-2 years post treatment in urban Uganda

OBJECTIVE

To determine the proportion of recurrent tuberculosis (TB) due to relapse with the patient's initial strain or reinfection with a new strain of Mycobacterium tuberculosis 1-2 years after anti-tuberculosis treatment in Uganda, a sub-Saharan TB-endemic country.

DESIGN

Records of patients with culture-confirmed TB who completed treatment at an urban Ugandan clinic were reviewed. Restriction fragment length polymorphism (RFLP) patterns were used to determine relapse or reinfection. Associations between human immunodeficiency virus (HIV) positivity and type of TB recurrence were determined.

RESULTS

Of 1701 patients cured of their initial TB episode with a median follow-up of 1.24 years, 171 (10%) had TB recurrence (8.4 per 100 person-years). Rate and risk factors for recurrence were similar to other studies from sub-Saharan Africa. Insertion sequence (IS) 6110-based RFLP of paired isolates from 98 recurrences identified 80 relapses and 18 reinfections. Relapses among HIV-positive and -negative patients were respectively 79% and 85% of recurrences.

CONCLUSIONS

Relapse was more common and presented earlier than reinfection in both HIV-positive and -negative TB patients 1-2 years after completing treatment. These findings impact both the choice of retreatment drug regimen, as relapsing patients are at higher risk for acquired drug resistance, and clinical trials of new TB regimens with relapse as clinical endpoint.

Smoking and 2-month culture conversion during anti-tuberculosis treatment

OBJECTIVE

To investigate risk factors for delayed sputum culture conversion to negative during anti-tuberculosis treatment, with an emphasis on smoking.

DESIGN

Nested case-control study of adults with non-cavitary, culture-confirmed pulmonary tuberculosis (TB) participating in an anti-tuberculosis treatment trial in Brazil. A case of delayed culture conversion was a patient who remained culture-positive after 2 months of treatment. Odds ratios with 95% confidence intervals were calculated.

RESULTS

Fifty-three cases and 240 control patients were analyzed. Smokers had three-fold greater odds of remaining culture-positive after 2 months of treatment (P = 0.007) than non-smokers, while smokers and ex-smokers who smoked >20 cigarettes a day had two-fold greater odds of remaining culture-positive after 2 months of treatment (P = 0.045).

CONCLUSION

Cigarette smoking adversely affects culture conversion during anti-tuberculosis treatment. Support for smoking cessation should be considered to improve outcomes in TB control programs.

Anti-tuberculosis treatment outcomes in HIV-infected adults exposed to isoniazid preventive therapy in Botswana

SETTING

Eight public health clinics in Gaborone and Francistown, Botswana.

OBJECTIVES

To describe the characteristics and outcomes of incident tuberculosis (TB) cases in human immunodeficiency virus (HIV) infected adults exposed to isoniazid preventive therapy (IPT) with access to antiretroviral and anti-tuberculosis treatment.

DESIGN

In 1995 HIV-infected adults, TB disease was excluded before commencing IPT. During and after receipt of 6 or 36 months of IPT, symptomatic participants were evaluated using chest radiographs, sputum microscopy, cultures and drug susceptibility testing (DST). Incident TB cases received ≥6 months of anti-tuberculosis treatment.

RESULTS

Seventy-five incident TB cases were identified among 619 symptomatic participants. The median duration of IPT in these cases was 6 months (range 1-35), and the median time to initiation of anti-tuberculosis treatment was 12 months after IPT cessation. Antiretroviral therapy (ART) was initiated before anti-tuberculosis treatment in 37 cases. Culture was positive in 43/58 (74%) TB cultures. DST was available for 38 cases, of which six (16%) were resistant to isoniazid (INH); 67/75 (89%) cases, including four with INH-monoresistant TB, completed anti-tuberculosis treatment or were cured.

CONCLUSIONS

With prompt initiation of anti-tuberculosis treatment and access to ART, excellent outcomes were achieved in a public health setting in HIV-infected adults who developed TB disease.

Assessing family members' motivational readiness and decision making for consenting to cadaveric organ donation

This study assessed the applicability of two important components of the transtheoretical model of behavior change (TTM) to family consent for cadaveric organ donation. Men and women (N = 169), who consented or refused to donate the organs of a family member, completed a telephone survey reflecting the stage of change and decisional balance constructs. Psychometric analyses resulted in a two-factor decisional balance scale: a seven-item scale representing negative perceptions of consent (cons), and a seven-item scale representing positive perceptions of consent (pros). The pros and cons were significantly associated with stage of readiness for donation consent and with the family consent decision. Research utilizing this measure has the potential to enhance intervention programs to increase donation consent rates.

Reasons for non-participation in an international multicenter trial of a new drug for tuberculosis treatment

SETTING

Clinical trials can provide a high standard of patient care and contribute to scientific knowledge; however, only a fraction of the patients screened participate and receive treatment as part of a trial.

OBJECTIVE

To explore reasons why patients were not enrolled in an international tuberculosis (TB) treatment trial and to compare experiences among study sites.

DESIGN

An analysis of reasons why patients were not enrolled was conducted among patients screened for a TB clinical trial at 26 sites in North and South America, Africa, and Europe.

RESULTS

Staff at study sites screened 1119 potential candidates for the trial: 61% (n = 686) were not enrolled due to 1) failure to meet eligibility criteria (n = 405, 59%), 2) site's decision (n = 168, 24%), or 3) candidate's choice (n = 113, 16%). Study staff recorded a total of 144 reasons for why they believed patients chose not to participate, including concerns over research (28%), conflicts with work or school (21%), and lifestyle and family issues (20%). Socio-demographic and geographic factors also influenced participation.

CONCLUSION

Increased evaluation of screening outcomes and of specific interventions, such as improved education and communication about trial procedures, may increase the efficiency of screening and enrollment in clinical trials.

Effect of HIV infection on tolerability and bacteriologic outcomes of tuberculosis treatment

SETTING

Two international, multicenter Phase 2 clinical trials examining fluoroquinolone-containing regimens in adults with smear-positive pulmonary tuberculosis (TB), conducted from July 2003 to March 2007. Both trials enrolled human immunodeficiency virus (HIV) infected participants who were not receiving antiretroviral therapy (ART) at TB treatment initiation.

OBJECTIVE

To assess the impact of HIV infection on TB treatment outcomes in Phase 2 clinical trials.

DESIGN

Cross-protocol analysis comparing the safety, tolerability and outcomes of anti-tuberculosis treatment by HIV status.

RESULTS

Of 750 participants who received at least one dose of study treatment, 123 (16%) were HIV-infected. Treatment completion rates were similar by HIV status (81% infected vs. 85% non-infected), as were rates of week 8 culture conversion (66% infected vs. 63% non-infected), and treatment failure (5% infected vs. 3% non-infected). Among HIV-infected participants, treatment failure detected using liquid media was more frequent in those treated thrice weekly (14% thrice weekly vs. 2% daily, P = 0.03). HIV-infected participants more frequently experienced an adverse event during the intensive phase treatment than non-HIV-infected participants (30% vs. 15%, P < 0.01).

CONCLUSION

HIV-infected persons not receiving ART had more adverse events during the intensive phase of anti-tuberculosis treatment, but tolerated treatment well. Failure rates were higher among HIV-infected persons treated with thrice-weekly intensive phase therapy.

Phase II trial of galiximab (anti-CD80 monoclonal antibody) plus rituximab (CALGB 50402): Follicular Lymphoma International Prognostic Index (FLIPI) score is predictive of upfront immunotherapy responsiveness

BACKGROUND

This phase II CALGB trial evaluated the activity and safety of an extended induction schedule of galiximab (G) plus rituximab (R) in untreated follicular lymphoma (FL).

PATIENTS AND METHODS

Patients with previously untreated FL (grades 1, 2, 3a) received 4 weekly infusions of G + R, followed by an additional dose every 2 months four times. International Workshop Response Criteria were used to evaluate response.

RESULTS

Sixty-one patients were treated and antibody infusions were well tolerated. The overall response rate (ORR) is 72.1% (95% confidence interval 59.2% to 82.9%): 47.6% complete response (CR)/unconfirmed complete response (CRu) and 24.6% partial response. At a median follow-up time of 4.3 years (range, 0.3-5.3 years) median progression-free survival (PFS) is 2.9 years. Notably, Follicular Lymphoma International Prognostic Index (FLIPI) correlated with ORR, CR rate, and PFS, and the low-risk FLIPI group (n = 12) achieved a 92% ORR, 75% CR/CRu rate, and 75% 3-year PFS.

CONCLUSIONS

An extended induction schedule of G + R in previously untreated FL is well tolerated and appears particularly efficacious in those patients with low-risk FLIPI scores. In addition, this trial served as the initial platform for additional CALGB 'doublet' combination regimes of rituximab plus other novel targeted agents.

Exercise dose response in muscle

Exercise increases peak VO2 partially through muscle adaptations. However, understanding muscle adaptations related to exercise dose is incomplete. This study investigated exercise training dose on capillaries per fiber and capillaries per area; and citrate synthase from vastus lateralis and related both to changes in peak VO2. This randomized trial compared 3 exercise doses: low amount-moderate intensity (n=40), low amount-high intensity (n=47), high amount-high intensity (n=41), and a control group (n=35). Both measures of capillary supply increased in all exercise groups (p<0.05). Low amount-high intensity and high amount-high intensity improved citrate synthase (p<0.05) and the low amount-moderate intensity citrate synthase approached significance (p=0.059). Muscle improvements were only related to improvements in peak VO2 in high amount-high intensity (citrate synthase, r=0.304; capillaries:fiber, r= - 0.318; p<0.05 and capillaries/mm2 r= - 0.310, p<0.05). These data suggest muscle adaptations occur following both low and high exercise doses, but are only related to improved peak VO2 following high amount-high intensity training.

Nicotine dependence and gender differences in smokers accessing community mental health services

Despite evidence of differences in smoking behaviour between women and men, few studies have assessed these differences in individuals with mental illnesses. In this cross-sectional study, we explored gender differences in smoking behaviour among 298 individuals (60% male) accessing community mental health services. Individuals with a psychotic disorder as compared with a non-psychotic disorder, and individuals using a greater number of substances were more likely to be male. Readiness to change, daily cigarette consumption and level of nicotine dependence did not differ between men and women; however, subjective ratings of tobacco addiction were higher in women than in men. Among women, only scores on the subjective tobacco addiction scale were associated with nicotine dependence, while among men, a variety of variables were associated with nicotine dependence. These factors are important for understanding individual differences in tobacco dependence among clients with mental illnesses, and are expected to inform future studies examining tobacco use in mental health treatment populations.

Time to detection of Mycobacterium tuberculosis as an alternative to quantitative cultures

Testing new drugs is critical to improving the treatment of tuberculosis. Quantitative cultures of Mycobacterium tuberculosis on solid media have been used in Phase 1 and 2 trials, but are time and resource intensive. Time to detection (TTD) of growth of M. tuberculosis in automated liquid culture systems is an alternative. TTD has been shown to correlate with CFU in quantitative cultures, and is faster and simpler to perform. We compared TTD in the BACTEC 460 liquid culture system with CFU in a clinical trial that included 110 subjects. Comparing all sputum cultures collected between baseline and 2 months we found a strong negative correlation between log(10) CFU and TTD (rho = -0.91). In addition, when TTD at baseline was compared with 1 and 2 month sputum culture positivity, subjects whose cultures were negative after 1 and 2 months had a significantly longer median baseline TTD compared with subjects whose cultures were positive at 1 and 2 months (5 vs. 3 days and 3 vs. 2 days, respectively). TTD compares closely with CFU and represents a faster, simpler alternative to quantitative cultures.

Reduction of contamination of mycobacterial growth indicator tubes using increased PANTA concentration

We assessed the effect of a double concentration of supplemental polymyxin B, amphotericin B, nalidixic acid, trimethoprim and azlocillin (PANTA) added to the Mycobacterial Growth Indicator Tube (MGIT) on contamination and positivity rates in 216 sputum cultures. Contamination rates were respectively 12.9% and 5.5% for samples processed using standard and double PANTA concentrations (P = 0.0001, McNemar's test). Thirty-five per cent of cultures performed using standard PANTA and 36.5% of those performed using two-fold PANTA concentrations were positive for Mycobacterium tuberculosis, compared to 25.9% of cultures inoculated on Ogawa medium. These results suggest that the use of MGIT with 2× PANTA may be useful in reducing culture contamination without reducing the diagnostic yield.

Acceptability of treatment of latent tuberculosis infection in newly HIV-infected young women in Uganda

We studied the acceptability of isoniazid preventive therapy (IPT) in newly human immunodeficiency virus (HIV) infected Ugandan women. Women were followed in an out-patient clinic where they received HIV care including IPT. Of 52 women who were purified protein derivative-positive, 48 were eligible for IPT and 39 (81%) completed therapy. This completion rate was higher than reported in similar observational studies.

Extensive genetic divergence associated with speciation in filamentous fungi

Little is known about genetic differentiation during speciation in fungi. The Collybia dryophila complex (Basidiomycetes: Tricholomataceae) contains several closely related groups of fungi at various levels of evolutionary divergence. Mating compatibility studies show there are several intersterile groups within the complex, three of which are distributed over two or more continents. Genetic relationships among five intersterility groups were compared by the method of DNA.DNA hybridization. Clustering techniques were used to reconstruct phylogenetic relationships of these fungi. Genic identity based on DNA.DNA hybridization corresponds well with mating compatibility. Reduced genic identity was observed between geographically isolated populations of a single mating group. This evidence suggests an allopatric mode of evolution for the C. dryophila group. These results indicate extensive genic divergence is associated with the appearance of intersterility barriers in basidiomycetous fungi. The levels of divergence observed in these and in other fungi are significantly higher than that observed in many other eukaryotes, and this suggests that the rate of molecular or morphological evolution in fungi may differ from that found in other organisms.

Serious pulmonary toxicity in patients with Hodgkin's lymphoma with SGN-30, gemcitabine, vinorelbine, and liposomal doxorubicin is associated with an FcγRIIIa-158 V/F polymorphism

BACKGROUND

Based on in vitro synergistic cytotoxicity when anti-CD30 antibodies are combined with gemcitabine, the Cancer and Leukemia Group B conducted a double-blind, randomized, phase II trial of SGN-30 with gemcitabine, vinorelbine, and pegylated liposomal doxorubicin (GVD) in patients with relapsed Hodgkin's lymphoma.

PATIENTS AND METHODS

In part 1 of the trial, 16 patients received SGN-30 with GVD to assess the safety of the combination. In part 2, patients were randomly allocated to SGN-30 (n = 7) or placebo (n = 7) with GVD to determine overall response rate (ORR).

RESULTS

ORR in all 30 patients was 63% (65% with SGN-30 plus GVD, n = 23, and 57% with placebo plus GVD, n = 7). Median event-free survival was 9.0 months, with no difference between the two arms. Grades 3-5 pneumonitis occurred in five patients receiving SGN-30 and GVD, leading to premature closure of the trial. All five patients with pulmonary toxicity had a V/F polymorphism in the FcγRIIIa gene (P = 0.008).

CONCLUSIONS

Together with historical data demonstrating a 2% incidence of pulmonary events with GVD, these results indicate that SGN-30 cannot safely be administered concurrently. The risk of pneumonitis with SGN-30 and GVD is greatest in patients with an FcγRIIIa V/F polymorphism.

Comparison of two concentrations of NALC-NaOH for decontamination of sputum for mycobacterial culture

This study compared the effect of using two different concentrations of sodium hydroxide (NaOH) in the N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) method for sputum decontamination on smear and culture positivity and the proportion of contaminated cultures: 14% of cultures were contaminated using the standard final 1% NaOH concentration during processing compared to 11% contaminated cultures using a final 1.25% NaOH concentration (P < 0.008). The proportion of cultures positive for mycobacteria decreased from 21% to 11% for sputum processed with 1% and 1.25% final NaOH concentrations, respectively (P < 0.001). Our findings suggest that a small reduction in culture contamination did not justify the considerable loss of positive cultures.

The value of end-of-treatment chest radiograph in predicting pulmonary tuberculosis relapse

SETTING

Patients with cavitary pulmonary tuberculosis (TB) on baseline chest radiograph (CXR) who remain culture-positive after 8 weeks of treatment are at high risk of relapse. The role of end-of-treatment (EOT) CXR in predicting relapse is unclear.

OBJECTIVE

To determine whether EOT CXR independently predicts TB relapse.

DESIGN

We conducted a secondary analysis of a randomized trial of intermittent treatment using rifapentine in the continuation phase of TB treatment among 1004 human immunodeficiency virus seronegative adults with culture-proven pulmonary TB.

RESULTS

Relapse occurred in 17.3% of subjects with persistent cavity on EOT CXR, in 7.6% of subjects with a cavity that resolved by EOT, and 2.5% (P=0.002 for trend) of subjects who never had a cavity. In multivariable analysis, patients with persistent cavity on EOT CXR were significantly more likely to relapse than patients with no cavity on baseline or 2-month CXR (hazard ratio [HR] 4.22, 95%CI 2.00-8.91), and were more likely to relapse than subjects whose early cavity had resolved by EOT CXR (HR 1.92, 95%CI 1.09-3.39).

CONCLUSION

A persistent cavity after 6 months of TB treatment was independently associated with disease relapse after controlling for other variables. EOT CXR may help predict those likely to relapse.

The oxidation of sulphite in animals systems

In animals the terminal step in the pathway for degradation of sulphur-containing amino acids is the oxidation of sulphite to sulphate. This reaction is catalysed by the enzyme sulphite oxidase. The enzyme contains molybdenum and a cytochrome b5 type haem, is localized in the mitochondrial intermembrane space and transfers electrons from sulphite to cytochrome c on the inner membrane. The sulphite oxidase protein has a molecular weight of 110 000 (chicken) to 122 000 (human) and exists as a dimer of identical subunits. The haem and molybdenum cofactors are present on separate domains of the molecule. The structure of the molydbenum cofactor has not been worked out in detail, but this cofactor is known to be present in many other molybdoenzymes including xanthine oxidase and nitrate reductase. Three cases of genetic sulphite oxidase deficiency in humans have been reported. The three affected children displayed mental retardation, neurological abnormalities and dislocated ocular lenses. The biochemical basis for lack of enzyme activity in each case has been studied. All three have been shown to lack the sulphite oxidase protein, but in one case this appears to be secondary to a defect in synthesis of the molybdenum cofactor. Sulphite oxidase deficiency has been produced in the rat by administration of high levels of tungsten. Sulphite oxidase-deficient animals are particularly susceptible to the toxic effects of sulphite and atmospheric sulphur dioxide.

Severity of Clostridium difficile-associated diarrhea in solid organ transplant patients

Clostridium difficile-associated diarrhea (CDAD) has a wide spectrum of disease severity. Studies have implicated immunosuppressants as a risk factor for severe disease. We hypothesized that solid organ transplant (SOT) patients with CDAD would be at greater risk for severe disease because of their profound immunosuppression. Adult SOT patients with CDAD seen at Duke University Medical Center between 1999 and 2003 were compared with a reference group of non-transplant patients with CDAD. The primary outcome was the development of complicated colitis defined as death, intensive care unit admission, or urgent colectomy within 30 days of diagnosis. A secondary outcome was relapse within 60 days. Eighty transplant and 86 non-transplant cases were reviewed. There was no significant difference in the development of complicated colitis (13.8% vs. 7.0%) or relapse rates (6.2% vs. 7.0%) between the 2 groups. In the entire sample, 18.5% of patients receiving corticosteroids unrelated to transplantation relapsed as compared with 4.5% not receiving corticosteroids (risk ratio 4.3, P=0.02). In conclusion, no significant difference was found in severity of CDAD between SOT patients and non-transplant patients. Exposure to corticosteroids was significantly associated with an increased risk of relapse and may warrant a longer treatment course.

Examining how contexts shape young children's perspectives of health

BACKGROUND

We know that the social conditions in which children live exert a strong influence on their health; yet, we do not know how children's experience of these conditions of daily life shape their perspectives of health.

METHODS

Through ethnographic research methods, the first author spent 1 year with the 14 6-year-old children involved in this research and examined how the contexts of daily life influenced the children's perspectives of health. The children involved in this study all lived in a neighbourhood characterized as having a complex of mid to high range of neighbourhood factors associated with vulnerability.

RESULTS

The findings demonstrate that the children were able to articulate the health requirements of physical activity and healthy eating that supports their health. However, there was a disparity between the children's health knowledge, their perceptions and their contextual realities in relation to health. Children spoke of concerns for their physical safety within their schools and neighbourhoods; their lack of free range of play, and that they had few opportunities to play with or get to know neighbourhood friends.

CONCLUSION

Professionals in contact with children and families who live in challenging social conditions need to be aware of how these contexts shape children's understanding of their own health potential.

Gemcitabine, vinorelbine, and pegylated liposomal doxorubicin (GVD), a salvage regimen in relapsed Hodgkin's lymphoma: CALGB 59804

BACKGROUND

Because of high single-agent activity and modest toxicity, we hypothesized the combination of gemcitabine (G), vinorelbine (V), and pegylated liposomal doxorubicin (D) would be an effective salvage therapy for Hodgkin's lymphoma (HL).

PATIENTS AND METHODS

A total of 91 patients participated. GVD was administered on days 1 and 8 every 21 days at doses of G 1000 mg/m(2), V 20 mg/m(2), and D 15 mg/m(2) for transplant-naive patients, and G 800 mg/m(2), V 15 mg/m(2), and D 10 mg/m(2) for post-transplant patients.

RESULTS

The dose-limiting toxicity was mucositis for the transplant-naive patients and febrile neutropenia for post-transplant patients. The overall response rate (RR) for all patients was 70% [95% confidence interval (CI) 59.8, 79.7], with 19% complete remissions. The 4-year event-free and overall survival rates in transplant-naive patients treated with GVD followed by autologous transplant were 52% (95% CI 0.34, 0.68) and 70% (95% CI 0.49, 0.84), and in the patients in whom prior transplant failed, these were 10% (95% CI 0.03, 0.22) and 34% (95% CI 0.17, 0.52), respectively.

CONCLUSIONS

GVD is a well-tolerated, active regimen for relapsed HL with results similar to those reported for more toxic regimens. High RRs in patients in whom prior transplant failed confirms this regimen's activity even in heavily pretreated patients.

Matrix metalloproteinases: influence on smooth muscle cells and atherosclerotic plaque stability

Atherosclerotic plaque rupture, with subsequent occlusive thrombosis, is the underlying cause of most cases of sudden cardiac death. Matrix metalloproteinases (MMPs) are thought to mediate the progression of stable atherosclerotic lesions to an unstable phenotype that is prone to rupture through the destruction of strength-giving extracellular matrix (ECM) proteins. Smooth muscle cells secrete and deposit ECM proteins and are, therefore, considered protective against atherosclerotic plaque destabilization. However, similar to inflammatory cells (e.g., macrophages), smooth muscle cells release numerous MMPs that are capable of digesting ECM proteins. Thus, the interaction of smooth muscle cells and MMPs in atherosclerotic plaques is complex and not fully understood. Recently, research into the roles of MMPs and their endogenous inhibitors (tissue inhibitors of metalloproteinases), and their effects on smooth muscle behavior during plaque destabilization has been aided by the development of reproducible animal models of plaque instability. A plethora of studies has demonstrated that MMPs directly modulate smooth muscle behavior with both beneficial and deleterious effects on atherosclerotic plaque stability, in addition to their canonical effects on ECM remodeling. Consequently, broad-spectrum MMP inhibition may inhibit plaque-stabilizing mechanisms, such as smooth muscle cell growth, while conversely retarding ECM destruction and subsequent rupture. Hence the development of selective MMP inhibitors, that spare inhibitory effects on smooth muscle cell function, may be useful therapies to prevent plaque rupture and in this regard MMP-12 appears to be a particularly attractive target.

Early and extended early bactericidal activity of levofloxacin, gatifloxacin and moxifloxacin in pulmonary tuberculosis

OBJECTIVE

To evaluate the early bactericidal activity (EBA) of the new fluoroquinolones levofloxacin, gatifloxacin and moxifloxacin in patients with pulmonary tuberculosis (PTB).

DESIGN

Randomized, open-label trial. Forty adults with newly diagnosed smear-positive PTB (10 per arm) were assigned to receive isoniazid (INH) 300 mg, levofloxacin 1000 mg, gatifloxacin 400 mg, or moxifloxacin 400 mg daily for 7 days. Sputum for quantitative culture was collected for 2 days before and daily during 7 days of monotherapy. Bactericidal activity was estimated by measuring the decline in bacilli during the first 2 days (EBA 0-2) and last 5 days of monotherapy (extended EBA, EBA 2-7). Laboratory staff were blinded to treatment assignment.

RESULTS

The EBA 0-2 of INH (0.67 log10 cfu/ml/day) was greater than that of moxifloxacin and gatifloxacin (0.33 and 0.35 log10 cfu/ml/day, respectively), but not of levofloxacin 1000 mg daily (0.45 log10 cfu/ml/day) (P = 0.14). Bactericidal activity between days 2 and 7 was similar for all three fluoroquinolones. In a pooled comparison, the EBA 2-7 of the fluoroquinolones was greater than for INH.

CONCLUSION

Moxifloxacin, gatifloxacin, and high-dose levofloxacin have excellent EBA, only slightly less than for INH, and greater extended EBA. These drugs warrant further study in the treatment of drug-susceptible TB.

SOME ASPECTS OF METHANE OXIDATION

Johnson, John L. (Montana State College, Bozeman) and Kenneth L. Temple. Some asspects of methane oxidation. J. Bacteriol. 84:456-458. 1962.-A culture of Pseudomonas methanica (Methanomonas methanica) was isolated from a film of growth on the water layer in a methane storage bottle. This organism differed from Dworkin and Foster's strain in pH optimum, requirement for growth factors, sensitivity to oxygen and optimal oxygen level, and minor cultural features. Highly significant interactions were found for the concentrations of oxygen, methane, and carbon dioxide in growth experiments.

Bioavailability of vitamin D from fortified process cheese and effects on vitamin D status in the elderly

We conducted 2 studies to determine the effect of vitamin D-fortified cheese on vitamin D status and the bioavailability of vitamin D in cheese. The first study was designed to determine the effect of 2 mo of daily consumption of vitamin D3-fortified (600 IU/d) process cheese on serum 25-hydroxyvitamin D (25-OHD), parathyroid hormone (PTH), and osteocalcin (OC) concentrations among 100 older (> or =60 yr) men and women. Participants were randomized to receive vitamin D-fortified cheese, nonfortified cheese, or no cheese. Serum levels of 25-OHD, PTH, and OC were measured at the beginning and end of the study. There were no differences in 25-OHD, PTH, or OC after 2 mo of fortified cheese intake. The vitamin D-fortified cheese group had a greater decrease in 25-OHD than other groups, due to higher baseline 25-OHD. A second study was conducted to determine whether the bioavailability of vitamin D2 in cheese (delivering 5880 IU of vitamin D2/56.7-g serving) and water (delivering 32,750 IU/250 mL) is similar and whether absorption differs between younger and older adults. The second study was a crossover trial involving 2 groups of 4 participants each (younger and older group) that received single acute feedings of either vitamin D2-fortified cheese or water. Serial blood measurements were taken over 24 h following the acute feeding. Peak serum vitamin D and area under the curve were similar between younger (23 to 50 yr) and older (72 to 84 yr) adults, and vitamin D2 was absorbed more efficiently from cheese than from water. These studies demonstrated that vitamin D in fortified process cheese is bioavailable, and that young and older adults have similar absorption. Among older individuals, consuming 600 IU of vitamin D3 daily from cheese for 2 mo was insufficient to increase serum 25-OHD during limited sunlight exposure.

Comparison of intermittent ethambutol with rifampicin-based regimens in HIV-infected adults with PTB, Kampala

BACKGROUND

The human immunodeficiency virus (HIV) is a key factor responsible for the high rates of tuberculosis (TB) in sub-Saharan Africa. Treatment of TB with rifampicin (R, RMP) containing short-course regimens is highly effective in HIV-infected adults. We conducted a study to compare the efficacy and safety of intermittent ethambutol (E, EMB) with two RMP-containing regimens to treat pulmonary TB in HIV-infected patients.

SETTING

National Tuberculosis Treatment Centre, Mulago Hospital, Kampala, Uganda.

DESIGN

This was a prospective cohort compared to two non-randomised control groups. The study group and the two control arms were treated with 2 months of isoniazid (H), RMP, pyrazinamide (Z) and EMB followed by 6 E3H3 for the study group and 4HR or 6HR for controls.

RESULTS

Between April 1993 and March 2000, 136 patients were enrolled in the 2EHRZ/E3H3 arm, 147 in the 2EHRZ/4HR arm and 266 in the 2EHRZ/6HR arm. The relapse rate was 18.2 per 100 person-years observation (PYO) for the study regimen compared to 9.7/100 PYO (P = 0.0063) and 4.8/100 PYO (P = 0.0001) in patients treated with 2 EHRZ/4HR or 2EHRZ/6HR, respectively.

CONCLUSION

The 2EHRZ/6E3H3 regimen is safe and effective but has a significant risk of relapse.

Bioactivation of latent transforming growth factor beta1 by Mycobacterium tuberculosis in human mononuclear phagocytes

Biologically active transforming growth factor beta 1 (TGFbeta1) has been identified at sites of Mycobacterium tuberculosis (MTB) infection in the lung; however, the underlying mechanism(s) for its activation is not clear. Here using an enzyme-linked immunospot assay for TGFbeta1, we show that human blood monocytes (MN) and alveolar macrophages (AM) produce bioactive TGFbeta1 upon stimulation by MTB. However, only MTB-stimulated MN increased TGFbeta1 production on a per cell basis. The frequency of TGFbeta1-producing MN was reduced by an inhibitor of plasmin, bdellin, indicating a role for plasmin pathways in the bioactivation of cytokine. The expression of urokinase plasminogen activator receptor (uPAR) mRNA and both surface and soluble uPAR (CD87) was increased in MTB-activated MN. However, antibody neutralization of uPAR suppressed bioactive TGFbeta1 in MN alone. Thus, the more immature MN, which are continuously recruited to the lung during tuberculosis (TB), have a higher capacity to bioactivate TGFbeta1 by expression of components of the plasmin pathway. Excess production and bioactivation of TGFbeta1 at sites of MTB infection may undermine host immune responses during TB.

Effect of Mycobacterium vaccae (SRL172) immunotherapy on radiographic healing in tuberculosis

OBJECTIVE

Controlled trials have failed to show an effect of Mycobacterium vaccae immunotherapy on treatment outcome and mortality in patients with tuberculosis (TB); however, several studies have suggested improvement in radiographic clearing and resolution of cavitary disease.

METHODS

To assess the effect of M. vaccae immunotherapy on radiographic healing in pulmonary TB, chest X-rays from three randomized placebo-controlled trials of M. vaccae given as a single injection during the first 2 weeks of treatment were interpreted by a single, masked assessor using a standard scheme. Endpoints were the overall degree of radiographic improvement or deterioration and changes in cavitary disease at the end of antituberculosis treatment and follow-up.

RESULTS

Of 1018 patients (478 HIV-infected; 540 HIV-uninfected) with an end of treatment or end of follow-up X-ray analyzed, 496 received M. vaccae and 522 received placebo. There was no difference in radiographic improvement or deterioration or cavitary disease at the end of treatment or follow-up comparing the M. vaccae and placebo groups. Results were similar comparing HIV-infected and HIV-uninfected patients.

CONCLUSION

Adjunctive immunotherapy of drug-susceptible pulmonary TB with M. vaccae during the first 2 weeks of treatment did not improve radiographic responses to treatment or resolution of cavitary disease.