Segmentation of retinal blood vessels using a novel clustering algorithm (RACAL) with a partial supervision strategy

In this paper, segmentation of blood vessels from colour retinal images using a novel clustering algorithm with a partial supervision strategy is proposed. The proposed clustering algorithm, which is a RAdius based Clustering ALgorithm (RACAL), uses a distance based principle to map the distributions of the data by utilising the premise that clusters are determined by a distance parameter, without having to specify the number of clusters. Additionally, the proposed clustering algorithm is enhanced with a partial supervision strategy and it is demonstrated that it is able to segment blood vessels of small diameters and low contrasts. Results are compared with those from the KNN classifier and show that the proposed RACAL performs better than the KNN in case of abnormal images as it succeeds in segmenting small and low contrast blood vessels, while it achieves comparable results for normal images. For automation process, RACAL can be used as a classifier and results show that it performs better than the KNN classifier in both normal and abnormal images.     

Interferon‐γ‐ and glucocorticoid‐mediated pathways synergize to enhance death of CD4+ CD8+ thymocytes during Salmonella enterica serovar Typhimurium infection

Thymic atrophy is known to occur during infections; however, there is limited understanding of its causes and of the cross-talk between different pathways. This study investigates mechanisms involved in thymic atrophy during a model of oral infection by Salmonella enterica serovar Typhimurium (S. typhimurium). Significant death of CD4⁺ CD8⁺ thymocytes, but not of single-positive thymocytes or peripheral lymphocytes, is observed at later stages during infection with live, but not heat-killed, bacteria. The death of CD4⁺ CD8⁺ thymocytes is Fas-independent as shown by infection studies with lpr mice. However, apoptosis occurs with lowering of mitochondrial potential and higher caspase-3 activity. The amounts of cortisol, a glucocorticoid, and interferon-γ (IFN-γ), an inflammatory cytokine, increase upon infection. To investigate the functional roles of these molecules, studies were performed using Ifnγ^−/− mice together with RU486, a glucocorticoid receptor antagonist. Treatment of C57BL/6 mice with RU486 does not affect colony-forming units (CFU), amounts of IFN-γ and mouse survival; however, there is partial rescue in thymocyte death. Upon infection, Ifnγ^−/− mice display higher CFU and lower survival but more surviving thymocytes are recovered. However, there is no difference in cortisol amounts in C57BL/6 and Ifnγ^−/− mice. Importantly, the number of CD4⁺ CD8⁺ thymocytes is significantly higher in Ifnγ^−/− mice treated with RU486 along with lower caspase-3 activity and mitochondrial damage. Hence, endogenous glucocorticoid and IFN-γ-mediated pathways are parallel but synergize in an additive manner to induce death of CD4⁺ CD8⁺ thymocytes during S. typhimurium infection. The implications of this study for host responses during infection are discussed.     

Emergence and Distribution of Foot‐and‐Mouth Disease Virus Serotype A and O in Bangladesh

Foot‐and‐mouth disease (FMD) is endemic in Bangladesh and is predominantly due to FMDV serotype O. In 2012, FMD outbreaks were identified in five different districts of Bangladesh. Of 56 symptomatic cattle epithelial tissue samples, diagnostic PCR assay based on 5′‐URT detected 38 FMDV infections. Viral genotyping targeting VP1‐encoding region confirmed emergence of two distinct serotypes, A and O with an abundance of serotype A in Chittagong and Gazipur districts and serotype O in Pabna and Faridpur. Only single lineage of both A and O was retrieved from samples of five different regions. Sequencing and phylogenetic analysis of VP1 sequences revealed that serotype O sequences were closely related to the Ind 2001 sublineage of Middle East–South Asia (ME‐SA) topotype that was previously circulating in Bangladesh, and serotype A sequences belonging to the genotype VII that was dominant in India during the last decade. The results suggest that extensive cross‐border animal movement from neighbouring countries is the most likely source of FMDV serotypes in Bangladesh.     

Correlation between in vitro growth and regulation of estrogen and progesterone receptors in rat mammary epithelial cells

The present studies examine 1) the effect of enzymatic cell dissociation on the level of cytosolic estrogen receptor (ER) and progesterone receptor (PR) for normal rat mammary tissue, 2) the concentrations of ER and PR in rat mammary epithelial (RME) cells cultured within collagen gel, and 3) correlations that may exist between receptor concentration and cultured RME cell proliferation after hormonal stimulation in vitro. After cell dissociation, ER was present in mammary cells at higher concentrations than those found in the whole gland, whereas PR concentrations were similar to those in the whole gland. As characterized by Scatchard analysis, PR and, to a lesser extent, ER can be maintained in cells cultured in serum-free medium within a collagen gel matrix. ER is apparently functional at relatively low levels, since estradiol did induce PR synthesis, and cytosolic ER was reduced by estrogen administration. However, estradiol had no mitogenic effect on RME cells in this system, supporting the hypothesis that there may be a dichotomy between estrogen's effect on growth and progesterone receptor synthesis. PRL plus progesterone act synergistically to induce cell proliferation in our system, and this correlates with increased concentrations of progesterone receptors. Thus, the collagen gel system appears to provide a useful in vitro model for the study of receptor regulation and cell proliferation.     

Neighborhood determinants of mood and anxiety disorders among men who have sex with men in New York City

Purpose

We examined the relationship between economic, physical, and social characteristics of neighborhoods, where men who have sex with men (MSM) lived and socialized, and symptom scores of depression and generalized anxiety disorder (GAD).

Methods

Participants came from a cross-sectional study of a population-based sample of New York City MSM recruited in 2010–2012 (n?=?1126). Archival and survey-based data were obtained on neighborhoods, where the men lived and where they socialized most often.

Results

MSM who socialized in neighborhoods with more economic deprivation and greater general neighborhood attachment experienced higher GAD symptoms. The relationship between general attachment to neighborhoods where MSM socialized and mental health depended on the level of gay community attachment: in neighborhoods characterized by greater gay community attachment, general neighborhood attachment was negatively associated with GAD symptoms, while in low gay community attachment neighborhoods, general neighborhood attachment had a positive association with GAD symptoms.

Conclusions

This study illustrates the downsides of having deep ties to social neighborhoods when they occur in the absence of broader access to ties with the community of one’s sexual identity. Interventions that help MSM cross the spatial boundaries of their social neighborhoods and promote integration of MSM into the broader gay community may contribute to the reduction of elevated rates of depression and anxiety in this population.

     

Surgical management of parapharyngeal tumors - our experience

Fifteen cases of parapharyngeal tumors treated surgically in ENT department of Calcutta National Medical College in last 2 years were included, 80% cases were of benign tumors, most common being schwannomas. Most important investigation was found to be CT scan. The study gives an overview regarding the surgical approach, based upon the extent and histology of the tumor and transcervical approach was found to be most efficient for all practical purpose.