Etiology and genetic factors in clefts of lip and/or palate reported at children’s hospital,Lahore, Pakistan

The etiology of cleft lip (CL) and/or cleft palate (CP) has been extensively studied in industrialized countries and is suggested to be heterogeneous with increasing evidence that both genetic and environmental factors are operating. To evaluate this assertion in a developing country like Pakistan, a case finding cross-sectional study was completed from 1^st July 2010 to 31^st May 2011 for 100 cases of CL and/or CP referred to the Genetic Clinic of the Children’s Hospital, Lahore, Pakistan. A clinical examination followed by necessary diagnostic work-up was completed for each case. The cause of CL and/or CP was clear in 18% of the children (n = 18). Environmental causes were found in 6 children (four mothers developed hyperthermia during the 2^nd month of gestation, one mother was diabetic, and one mother was a known case of epilepsy and took sodium valproate throughout her pregnancy). Six children were suffering from known genetic malformation syndromes (each with Jarcho-Levin syndrome, Oral-Facial-Digital syndrome type XI, Oral-Duplication syndrome, Kabuki syndrome, Fronto-nasal dysplasia and Nager syndrome). Novel chromosomal aberrations were identified in 2 children. In 82% of the children (n = 82) the cause of oro-facial clefts remained unknown. Impact of gender and consanguinity on the development of CL and/or CP was also studied. Prevalence of CP was significantly more among female children as compared to that in males (P < 0.05). Associated anomalies were present in 18% of the cases, anomalies of the craniofacial region being the most common. These findings were compared with regional and international studies.     

Horizontal gene and chromosome transfer in plant pathogenic fungi affecting host range

Plant pathogenic fungi adapt quickly to changing environments including overcoming plant disease resistance genes. This is usually achieved by mutations in single effector genes of the pathogens, enabling them to avoid recognition by the host plant. In addition, horizontal gene transfer (HGT) and horizontal chromosome transfer (HCT) provide a means for pathogens to broaden their host range. Recently, several reports have appeared in the literature on HGT, HCT and hybridization between plant pathogenic fungi that affect their host range, including species of Stagonospora/Pyrenophora, Fusarium and Alternaria. Evidence is given that HGT of the ToxA gene from Stagonospora nodorum to Pyrenophora tritici-repentis enabled the latter fungus to cause a serious disease in wheat. A nonpathogenic Fusarium species can become pathogenic on tomato by HCT of a pathogenicity chromosome from Fusarium oxysporum f.sp lycopersici, a well-known pathogen of tomato. Similarly, Alternaria species can broaden their host range by HCT of a single chromosome carrying a cluster of genes encoding host-specific toxins that enabled them to become pathogenic on new hosts such as apple, Japanese pear, strawberry and tomato, respectively. The mechanisms HGT and HCT and their impact on potential emergence of fungal plant pathogens adapted to new host plants will be discussed.     

Epithelial,dendritic, and CD4 T cell regulation of and by reactive oxygen and nitrogen species in allergic sensitization

Background

While many of the contributing cell types and mediators of allergic asthma are known, less well understood are the factors that induce allergy in the first place. Amongst the mediators speculated to affect initial allergen sensitization and the development of pathogenic allergic responses to innocuous inhaled antigens and allergens are exogenously or endogenously generated reactive oxygen species (ROS) and reactive nitrogen species (RNS).

Scope of review

The interactions between ROS/RNS, dendritic cells (DCs), and CD4⁺ T cells, as well as their modulation by lung epithelium, are of critical importance for the genesis of allergies that later manifest in allergic asthma. Therefore, this review will primarily focus on the initiation of pulmonary allergies and the role that ROS/RNS may play in the steps therein, using examples from our own work on the roles of NO₂ exposure and airway epithelial NF-κB activation.

Major conclusions

Endogenously generated ROS/RNS and those encountered from environmental sources interact with epithelium, DCs, and CD4⁺ T cells to orchestrate allergic sensitization through modulation of the activities of each of these cell types, which quantitiatively and qualitatively dictate the degree and type of the allergic asthma phenotype.

General significance

Knowledge of the effects of ROS/RNS at the molecular and cellular levels has the potential to provide powerful insight into the balance between inhalational tolerance (the typical immunologic response to an innocuous inhaled antigen) and allergy, as well as to potentially provide mechanistic targets for the prevention and treatment of asthma.     

Structure of a four-way bridged ParB-DNA complex provides insight into P1 segrosome assembly

The plasmid partition process is essential for plasmid propagation and is mediated by par systems, consisting of centromere-like sites and two proteins, ParA and ParB. In the first step of partition by the archetypical P1 system, ParB binds a complicated centromere-like site to form a large nucleoprotein segrosome. ParB is a dimeric DNA-binding protein that can bridge between both A-boxes and B-boxes located on the centromere. Its helix-turn-helix domains bind A-boxes and the dimer domain binds B-boxes. Binding of the first ParB dimer nucleates the remaining ParB molecules onto the centromere site, which somehow leads to the formation of a condensed segrosome superstructure. To further understand this unique DNA spreading capability of ParB, we crystallized and determined the structure of a 1:2 ParB-(142-333):A3-B2-box complex to 3.35A resolution. The structure reveals a remarkable four-way, protein-DNA bridged complex in which both ParB helix-turn-helix domains simultaneously bind adjacent A-boxes and the dimer domain bridges between two B-boxes. The multibridging capability and the novel dimer domain-B-box interaction, which juxtaposes the DNA sites close in space, suggests a mechanism for the formation of the wrapped solenoid-like segrosome superstructure. This multibridging capability of ParB is likely critical in its partition complex formation and pairing functions.     

The energetic state within hibernating myocardium is normal during dobutamine despite inhibition of ATP-dependent potassium channel opening with glibenclamide

Within hibernating myocardium, it is uncertain whether a normal energetic state is present at baseline and whether maintaining that energy state during a catecholamine challenge is dependent on ATP-dependent potassium channel opening. In this study, 16 swine underwent a thoracotomy with placement of an external constrictor on the left anterior descending coronary artery (LAD) (hibernation model). Seven additional swine underwent a sham operation. At 10 wk, the myocardial energetic state in the LAD region was assessed by (31)P-NMR spectroscopy, and the ratio of phosphocreatine to ATP (PCr/ATP) was determined at baseline, during glibenclamide treatment (0.5 mg/kg bolus with 50 microg/min iv), and during addition of dobutamine (40 microg x kg(-1) x min(-1) iv). At baseline, transmural blood flow in the LAD and remote region was 0.75 +/- 0.11 and 0.88 +/- 0.09 ml x min(-1) x g(-1), respectively (P < 0.01), in hibernating hearts and 0.83 +/- 0.12 and 0.88 +/- 0.15 ml x min(-1) x g(-1), respectively (not significant), in sham-operated hearts. Under basal conditions, PCr/ATP in the LAD region of hibernating and sham pigs was 2.15 +/- 0.04 and 2.11 +/- 0.05, respectively (not significant). In sham pigs, addition of dobutamine to glibenclamide increased the double product from 10.4 +/- 0.8 to 23.9 +/- 4.0 mmHg x beats x min(-1) x 1,000 (P < 0.05) and decreased transmural PCr/ATP from 2.06 +/- 0.06 to 1.69 +/- 0.06 (P < 0.05). Dobutamine increased the double product in hibernating pigs in a similar fashion and, despite a 40% lower blood flow response, induced an equivalent decrease in PCr/ATP from 2.04 +/- 0.04 to 1.73 +/- 0.08 (P < 0.05). In conclusion, we found that, in chronic hibernating swine myocardium with reduced basal blood flow and perfusion reserve, the transmural energetic state, defined by PCr/ATP, is normal during addition of dobutamine, despite inhibition of ATP-dependent potassium channel opening with glibenclamide. These data suggest that important adaptations other than the ATP-dependent potassium channel opening allow hibernating myocardium to operate over a lower range of the oxygen supply-demand relationship to protect against myocardial ischemia.     

DNA Barcoding of Bemisia tabaci Complex (Hemiptera: Aleyrodidae) Reveals Southerly Expansion of the Dominant Whitefly Species on Cotton in Pakistan

Background

Although whiteflies (Bemisia tabaci complex) are an important pest of cotton in Pakistan, its taxonomic diversity is poorly understood. As DNA barcoding is an effective tool for resolving species complexes and analyzing species distributions, we used this approach to analyze genetic diversity in the B. tabaci complex and map the distribution of B. tabaci lineages in cotton growing areas of Pakistan.

Methods/Principal Findings

Sequence diversity in the DNA barcode region (mtCOI-5′) was examined in 593 whiteflies from Pakistan to determine the number of whitefly species and their distributions in the cotton-growing areas of Punjab and Sindh provinces. These new records were integrated with another 173 barcode sequences for B. tabaci, most from India, to better understand regional whitefly diversity. The Barcode Index Number (BIN) System assigned the 766 sequences to 15 BINs, including nine from Pakistan. Representative specimens of each Pakistan BIN were analyzed for mtCOI-3′ to allow their assignment to one of the putative species in the B. tabaci complex recognized on the basis of sequence variation in this gene region. This analysis revealed the presence of Asia II 1, Middle East-Asia Minor 1, Asia 1, Asia II 5, Asia II 7, and a new lineage “Pakistan”. The first two taxa were found in both Punjab and Sindh, but Asia 1 was only detected in Sindh, while Asia II 5, Asia II 7 and “Pakistan” were only present in Punjab. The haplotype networks showed that most haplotypes of Asia II 1, a species implicated in transmission of the cotton leaf curl virus, occurred in both India and Pakistan.

Conclusions

DNA barcodes successfully discriminated cryptic species in B. tabaci complex. The dominant haplotypes in the B. tabaci complex were shared by India and Pakistan. Asia II 1 was previously restricted to Punjab, but is now the dominant lineage in southern Sindh; its southward spread may have serious implications for cotton plantations in this region.     

Adverse events among HIV/MDR-TB co-infected patients receiving antiretroviral and second line anti-TB treatment in Mumbai, India

Background

Significant adverse events (AE) have been reported in patients receiving medications for multidrug- and extensively-drug-resistant tuberculosis (MDR-TB & XDR-TB). However, there is little prospective data on AE in MDR- or XDR-TB/HIV co-infected patients on antituberculosis and antiretroviral therapy (ART) in programmatic settings.

Methods

Médecins Sans Frontières (MSF) is supporting a community-based treatment program for drug-resistant tuberculosis in HIV-infected patients in a slum setting in Mumbai, India since 2007. Patients are being treated for both diseases and the management of AE is done on an outpatient basis whenever possible. Prospective data were analysed to determine the occurrence and nature of AE.

Results

Between May 2007 and September 2011, 67 HIV/MDR-TB co-infected patients were being treated with anti-TB treatment and ART; 43.3% were female, median age was 35.5 years (Interquartile Range: 30.5–42) and the median duration of anti-TB treatment was 10 months (range 0.5–30). Overall, AE were common in this cohort: 71%, 63% and 40% of patients experienced one or more mild, moderate or severe AE, respectively. However, they were rarely life-threatening or debilitating. AE occurring most frequently included gastrointestinal symptoms (45% of patients), peripheral neuropathy (38%), hypothyroidism (32%), psychiatric symptoms (29%) and hypokalaemia (23%). Eleven patients were hospitalized for AE and one or more suspect drugs had to be permanently discontinued in 27 (40%). No AE led to indefinite suspension of an entire MDR-TB or ART regimen.

Conclusions

AE occurred frequently in this Mumbai HIV/MDR-TB cohort but not more frequently than in non-HIV patients on similar anti-TB treatment. Most AE can be successfully managed on an outpatient basis through a community-based treatment program, even in a resource-limited setting. Concerns about severe AE in the management of co-infected patients are justified, however, they should not cause delays in the urgently needed rapid scale-up of antiretroviral therapy and second-line anti-TB treatment.