A Population-based Study of Hospital Admission Incidence Rate and Bacterial Aetiology of Acute Lower Respiratory Infections in Children Aged Less Than Five Years in Bangladesh

The research was carried out to study the rate of population-based hospital admissions due to acute lower respiratory infections (ALRIs) and bacterial aetiology of ALRIs in children aged less than five years in Bangladesh. A cohort of children aged less than five years in a rural surveillance population in Matlab, Bangladesh, was studied for two years. Cases were children admitted to the Matlab Hospital of ICDDR,B with a diagnosis of severe ALRIs. Bacterial aetiology was determined by blood culture. Antimicrobial resistance patterns of Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (Spn) isolates were determined using the disc-diffusion method. In total, 18,983 children aged less than five years contributed to 24,902 child-years of observation (CYO). The incidence of ALRI-related hospital admissions was 50.2 per 1,000 CYO. The incidences of ALRI were 67% higher in males than in females and were higher in children aged less than two years than in older children. About 34% of the cases received antibiotics prior to hospitalization. Of 840 blood samples cultured, 39.4% grew a bacterial isolate; 11.3% were potential respiratory pathogens, and the rest were considered contaminants. The predominant isolates were Staphylococcus aureus (4.5%). Hib (0.4%) and Spn (0.8%) were rarely isolated; however, resistance of both these pathogens to trimethoprim-sulphamethoxazole was common. The rate of ALRI-related hospitalizations was high. The high rate of contamination, coupled with high background antibiotic use, might have contributed to an underestimation of the burden of Hib and Spn. Future studies should use more sensitive methods and more systematically look for resistance patterns of other pathogens in addition to Hib and Spn

A Population-based Study of Hospital Admission Incidence Rate and Bacterial Aetiology of Acute Lower Respiratory Infections in Children Aged Less Than Five Years in Bangladesh

The research was carried out to study the rate of population-based hospital admissions due to acute lower respiratory infections (ALRIs) and bacterial aetiology of ALRIs in children aged less than five years in Bangladesh. A cohort of children aged less than five years in a rural surveillance population in Matlab, Bangladesh, was studied for two years. Cases were children admitted to the Matlab Hospital of ICDDR,B with a diagnosis of severe ALRIs. Bacterial aetiology was determined by blood culture. Antimicrobial resistance patterns of Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (Spn) isolates were determined using the disc-diffusion method. In total, 18,983 children aged less than five years contributed to 24,902 child-years of observation (CYO). The incidence of ALRI-related hospital admissions was 50.2 per 1,000 CYO. The incidences of ALRI were 67% higher in males than in females and were higher in children aged less than two years than in older children. About 34% of the cases received antibiotics prior to hospitalization. Of 840 blood samples cultured, 39.4% grew a bacterial isolate; 11.3% were potential respiratory pathogens, and the rest were considered contami\uadnants. The predominant isolates were Staphylococcus aureus (4.5%). Hib (0.4%) and Spn (0.8%) were rarely isolated; however, resistance of both these pathogens to trimethoprim-sulphamethoxazole was common. The rate of ALRI-related hospitalizations was high. The high rate of contamination, coupled with high background antibiotic use, might have contributed to an underestimation of the burden of Hib and Spn. Future studies should use more sensitive methods and more systematically look for resistance patterns of other pathogens in addition to Hib and Spn

TRPA1 is essential for the vascular response to environmental cold exposure

This work was supported by the British Heart Foundation and a Capacity Building Award in Integrative Mammalian Biology. It was also supported by Arthritis Research UK and XK is supported by a British Pharmacological Society AJ Clark studentship

Computational Design of Auxotrophy-Dependent Microbial Biosensors for Combinatorial Metabolic Engineering Experiments

Combinatorial approaches in metabolic engineering work by generating genetic diversity in a microbial population followed by screening for strains with improved phenotypes. One of the most common goals in this field is the generation of a high rate chemical producing strain. A major hurdle with this approach is that many chemicals do not have easy to recognize attributes, making their screening expensive and time consuming. To address this problem, it was previously suggested to use microbial biosensors to facilitate the detection and quantification of chemicals of interest. Here, we present novel computational methods to: (i) rationally design microbial biosensors for chemicals of interest based on substrate auxotrophy that would enable their high-throughput screening; (ii) predict engineering strategies for coupling the synthesis of a chemical of interest with the production of a proxy metabolite for which high-throughput screening is possible via a designed bio-sensor. The biosensor design method is validated based on known genetic modifications in an array of E. coli strains auxotrophic to various amino-acids. Predicted chemical production rates achievable via the biosensor-based approach are shown to potentially improve upon those predicted by current rational strain design approaches. (A Matlab implementation of the biosensor design method is available via http://www.cs.technion.ac.il/~tomersh/tools)

Cyclic AMP acts through Rap1 and JNK signaling to increase expression of cutaneous smooth muscle α2C-adrenoceptors

Cold increases cutaneous vasoconstriction by unmasking the contractile activity of α2C-adrenoceptors (α2C-ARs) in vascular smooth muscle cells (VSMCs), which is mediated by the cold-induced mobilization of α2C-ARs from the transGolgi to the cell surface. The expression of α2C-ARs in human cutaneous VSMCs is under dual regulation by cyclic AMP: gene transcription is inhibited by cyclic AMP acting through protein kinase A but is increased by cyclic AMP acting through the exchange protein directly activated by cyclic AMP (EPAC) and the GTP-binding protein Rap1. Experiments were performed to further characterize the Rap1 signaling pathway. Forskolin (10 μM), the selective EPAC activator, 8-pCPT-2′-O-Me-cyclic AMP (CMC; 100 μM), or a constitutively active mutant of Rap1 (Rap1CA) increased the activity of c-Jun NH2-terminal kinase (JNK) in human cutaneous VSMCs. This was associated with the increased phosphorylation of c-Jun and activation of an activator protein (AP)-1 reporter construct, which were inhibited by the JNK inhibitor SP600125 (3 μM). Rap1CA increased the activity of an α2C-AR promoter-reporter construct, which was inhibited by SP600125 (3 μM) or by the mutation of an AP-1 binding site in the α2C-AR promoter. Furthermore, forskolin (10 μM) or CMC (100 μM) increased the expression of the α2C-AR protein, and these effects were inhibited by SP600125 (3 μM). Therefore, cyclic AMP increases the expression of α2C-ARs in cutaneous VSMCs by activating a novel Rap1 signaling pathway, mediated by the activation of JNK, AP-1, and the subsequent transcriptional activation of the α2C-AR gene. By increasing the expression of cold-responsive α2C-ARs, this pathway may contribute to enhanced cold-induced vasoconstriction in the cutaneous circulation, including Raynaud's phenomenon

Redox regulation of vascular smooth muscle cell differentiation

Experiments were performed to determine the role of reactive oxygen species (ROS) in regulating vascular smooth muscle cell (VSMC) phenotype. After quiescence, cultured human VSMCs increased their expression of differentiation proteins (alpha-actin, calponin, and SM1 and SM2 myosin), but not beta-actin. ROS activity, determined using the H(2)O(2)-sensitive probe dichlorodihydrofluorescein (DCF), remained high in quiescent cells and was inhibited by catalase (3000 U/mL) or by N-acetylcysteine (NAC, 2 to 20 mmol/L). A superoxide dismutase mimic (SOD; MnTMPyP, 25 micromol/L) or SOD plus low concentrations of NAC (SODNAC2, 2 mmol/L) increased DCF fluorescence, which was inhibited by catalase or by NAC (10 to 20 mmol/L). Inhibition of ROS activity (by catalase or NAC) decreased the baseline expression of differentiation proteins, whereas elevation of ROS (by SOD or SODNAC2) increased expression of the differentiation markers. The latter effect was blocked by catalase or by NAC (10 to 20 mmol/L). None of the treatments altered beta-actin expression. SODNAC2-treated cells demonstrated contractions to endothelin that were absent in proliferating cells. p38 Mitogen-activated protein kinase (MAPK) activity was decreased when ROS activity was reduced (NAC, 10 mmol/L) and was augmented when ROS activity was increased (SODNAC2). Inhibition of p38 MAPK with pyridyl imidazole compound (SB202190, 2 to 10 micromol/L) reduced expression of differentiation proteins occurring under basal conditions and in response to SODNAC2. Transduction of VSMCs with an adenovirus encoding constitutively active MKK6, an activator of p38 MAPK, increased expression of differentiation proteins, whereas transduction with an adenovirus encoding dominant-negative p38 MAPK decreased expression of the differentiation proteins. These findings demonstrate that ROS can increase VSMC differentiation through a p38 MAPK-dependent pathway