Black tea and theaflavins suppress various inflammatory modulators and i-NOS mediated nitric oxide synthesis during gastric ulcer healing

The modulation of the cyclooxygenase-independent pathway by black tea (BT) and its constituent theaflavins (TFs) during their healing action against indomethacin-induced stomach ulceration in mice was investigated. On the 3(rd) day of its administration, indomethacin (18 mg/kg) induced maximum stomach ulceration, which was associated with increased myeloperoxidase (MPO) activity (93.3%, p<0.001), and inducible nitric oxide synthase (iNOS) expression (1.6-fold, p<0.001), along with augmented levels of serum nitrite (1.5-fold, p<0.001), selectins and cell adhesion molecules (CAMs), as well as reduced endothelial nitric oxide synthase (eNOS) expression (60%, p<0.001). Treatment with BT (40 mg/kg) and TF (1 mg/kg) for 3 days reversed these parameters and provided excellent (78-81%) ulcer healing. However, alterations of NOS expressions and levels of selectins and CAMs were only partially responsible for the excellent healing capacity (～80%) of omeprazole (3 mg/kg × 3 days).     

Imaging in vivo neuronal transport in genetic model organisms using microfluidic devices

Microfluidic devices have been developed for imaging behavior and various cellular processes in Caenorhabditis elegans, but not subcellular processes requiring high spatial resolution. In neurons, essential processes such as axonal, dendritic, intraflagellar and other long-distance transport can be studied by acquiring fast time-lapse images of green fluorescent protein (GFP)-tagged moving cargo. We have achieved two important goals in such in vivo studies namely, imaging several transport processes in unanesthetized intact animals and imaging very early developmental stages. We describe a microfluidic device for immobilizing C. elegans and Drosophila larvae that allows imaging without anesthetics or dissection. We observed that for certain neuronal cargoes in C. elegans, anesthetics have significant and sometimes unexpected effects on the flux. Further, imaging the transport of certain cargo in early developmental stages was possible only in the microfluidic device. Using our device we observed an increase in anterograde synaptic vesicle transport during development corresponding with synaptic growth. We also imaged Q neuroblast divisions and mitochondrial transport during early developmental stages of C. elegans and Drosophila, respectively. Our simple microfluidic device offers a useful means to image high-resolution subcellular processes in C. elegans and Drosophila and can be readily adapted to other transparent or translucent organisms.     

Snapin mediates incretin action and augments glucose-dependent insulin secretion

Impaired insulin secretion contributes to the pathogenesis of type 2 diabetes mellitus (T2DM). Treatment with the incretin hormone glucagon-like peptide-1 (GLP-1) potentiates insulin secretion and improves metabolic control in humans with T2DM. GLP-1 receptor-mediated signaling leading to insulin secretion occurs via cyclic AMP stimulated protein kinase A (PKA)- as well as guanine nucleotide exchange factor-mediated pathways. However, how these two pathways integrate and coordinate insulin secretion remains poorly understood. Here we show that these incretin-stimulated pathways converge at the level of snapin, and that PKA-dependent phosphorylation of snapin increases interaction among insulin secretory vesicle-associated proteins, thereby potentiating glucose-stimulated insulin secretion (GSIS). In diabetic islets with impaired GSIS, snapin phosphorylation is reduced, and expression of a snapin mutant, which mimics site-specific phosphorylation, restores GSIS. Thus, snapin is a critical node in GSIS regulation and provides a potential therapeutic target to improve β cell function in T2DM.     

Estradiol-mediated suppression of CYP1B1 expression in mouse MA-10 Leydig cells is independent of protein kinase A and estrogen receptor

Estrogens have multifaceted roles in mammalian testis. In the present study, we focused on estradiol as a potential regulator of testicular cytochrome P450 1B1 (CYP1B1) expression and investigated the possible mechanisms involved in the estradiol-mediated suppression. CYP1B1 protein levels were measured in the testes of rats that were treated with 17β-estradiol benzoate (1.5 mg/kg) at different stages of development. In addition, CYP1B1 mRNA levels were measured in mouse MA-10 Leydig tumor cells treated with (a) various concentrations of 17β-estradiol benzoate, (b) 17β-estradiol benzoate in the presence of exogenous luteinizing hormone (LH), or (c) 17β-estradiol benzoate in the presence of ICI 182,780, a competitive steroidal antagonist of estrogen receptors (ERs). Treatment of neonatal, pubertal, or adult rats with 17β-estradiol benzoate was associated with a reduction of approximately 90% in testicular CYP1B1 protein content compared to age-matched controls. Treatment of MA-10 cells with 17β-estradiol benzoate (10-500 nM) produced a concentration- and time-dependent decrease in CYP1B1 mRNA levels, but had no effect on LH receptor mRNA levels or on protein kinase A (PKA) activity. However, 17β-estradiol benzoate (10-500 nM), regardless of the concentration tested, failed to attenuate the LH-elicited increase in CYP1B1 mRNA or PKA activity in MA-10 cells that were co-treated with LH and estradiol. Similarly, ICI 182,780 (10-1000 μM) did not reverse the suppressive effect of estradiol on CYP1B1 mRNA expression in MA-10 cells co-treated with estradiol and ICI 182,780. The results indicate that downregulation of testicular CYP1B1 by estradiol was independent of PKA activity and was not mediated by ERs in MA-10 cells.     

Alterations of <Emphasis Type="Italic">ATM</Emphasis> and <Emphasis Type="Italic">CADM1</Emphasis> in chromosomal 11q22.3–23.2 region are associated with the development of invasive cervical carcinoma

To understand the importance of chr11q22.3–23.2 region in the development of cervical cancer, we have studied the genetic and epigenetic alterations of the candidate genes ATM, PPP2R1B, SDHD and CADM1 in cervical intraepithelial neoplasia (CIN) and cervical carcinoma (CACX) samples. Our study revealed low expression and high alterations (methylation/deletion) (55–59%) of ATM and CADM1 genes along with poor patient outcome. The alterations of ATM and CADM1 are associated with the progression of tumor from CIN to Stage I/II, thus implying their role in early invasiveness. The two genes, PPP2R1B and SDHD, lying in between ATM and CADM1, have low frequency of alterations, and majority of the alterations are in CACX samples, indicating that their alterations might be associated with disease progression. Expressions (mRNA/protein) of the genes showed concordance with their molecular alterations. Significant co-alteration of ATM and CADM1 points to their synergic action for the development of CACX. Mutation is, however, a rare phenomenon for inactivation of ATM. Association between the alteration of ATM and CHEK1 and poor survival of the patients having co-alterations of ATM and CHEK1 points to the DNA damage response pathway disruption in development of CACX. Thus, our data suggest that inactivation of ATM–CHEK1-associated DNA damage response pathway and CADM1-associated signaling network might have an important role in the development of CACX.     

A comparison of stress distributions for different surgical procedures, screw dimensions and orientations for a Temporomandibular joint implant

Finite element analysis is a useful analytical tool for the design of biomedical implants. The aim of this study was to investigate the behavior of temporomandibular joint implants with multiple design variables of the screws used for fixation of the implant. A commercially available implant with full mandible was analyzed using a finite element software package. The effects of different design variables such as orientation, diameter and stem length of the screws on the stress distribution in bone for two different surgical procedures were investigated. Considering the microstrain in bone as a principal factor, the acceptable ranges for screw diameter and length were determined. Parallel orientation of the screws performed better from a stress point of view when compared to the zig-zag orientation. Sufficient contact between the implant collar and mandibular condyle was shown to reduce the peak stresses which may lead to long term success. The distance between screw holes in the parallel orientation was much closer when compared to the zig-zag orientation. However, the stresses in bone near the screw hole area for the parallel orientation were within acceptable limits.     

Interaction between differentiating cell- and niche-derived signals in hematopoietic progenitor maintenance

Maintenance of a hematopoietic progenitor population requires extensive interaction with cells within a microenvironment or niche. In the Drosophila hematopoietic organ, niche-derived Hedgehog signaling maintains the progenitor population. Here, we show that the hematopoietic progenitors also require a signal mediated by Adenosine deaminase growth factor A (Adgf-A) arising from differentiating cells that regulates extracellular levels of adenosine. The adenosine signal opposes the effects of Hedgehog signaling within the hematopoietic progenitor cells and the magnitude of the adenosine signal is kept in check by the level of Adgf-A secreted from differentiating cells. Our findings reveal signals arising from differentiating cells that are required for maintaining progenitor cell quiescence and that function with the niche-derived signal in maintaining the progenitor state. Similar homeostatic mechanisms are likely to be utilized in other systems that maintain relatively large numbers of progenitors that are not all in direct contact with the cells of the niche.     

Live bird markets of Bangladesh: H9N2 viruses and the near absence of highly pathogenic H5N1 influenza

Avian influenza surveillance in Bangladesh has been passive, relying on poultry farmers to report suspected outbreaks of highly pathogenic H5N1 influenza. Here, the results of an active surveillance effort focusing on the live-bird markets are presented. Prevalence of influenza infection in the birds of the live bird markets is 23.0%, which is similar to that in poultry markets in other countries. Nearly all of the isolates (94%) were of the non-pathogenic H9N2 subtype, but viruses of the H1N2, H1N3, H3N6, H4N2, H5N1, and H10N7 subtypes were also observed. The highly pathogenic H5N1-subtype virus was observed at extremely low prevalence in the surveillance samples (0.08%), and we suggest that the current risk of infection for humans in the retail poultry markets in Bangladesh is negligible. However, the high prevalence of the H9 subtype and its potential for interaction with the highly pathogenic H5N1-subtype, i.e., reassortment and attenuation of host morbidity, highlight the importance of active surveillance of the poultry markets.