Unwrapping the phase portrait features of adventitious crackle for auscultation and classification: a machine learning approach

Journal of Biological Physics - The paper delves into the plausibility of applying fractal, spectral, and nonlinear time series analyses for lung auscultation. The thirty-five sound signals of...     

Effect of metformin and spironolactone therapy on OGTT in patients with polycystic ovarian syndrome - a retrospective analysis

Background: Metformin (an insulin sensitizer) and spironolactone (an antiandrogen) are both used for treatment of polycystic ovary syndrome. We analyzed the effect of 6 months of therapy with these drugs on body weight and glucose tolerance. Results: This was a retrospective analysis of polycystic ovarian syndrome (PCOS) cases on treatment. There were 88 patients with PCOS-42 were on metformin 1 g daily and 46 were taking spironolactone 50-75 mg daily. 21 of 42 had abnormal glucose tolerance (AGT) in the metformin group and 13 of 46 had AGT in the spironolactone group. Patients on metformin reported a greater reduction in body weight, whereas there was no change in body weight with spironolactone therapy (67.6-63.7 versus 59.6-59.2 kg). There was a significant reduction in the 1 and 2 h glucose and insulin levels with metformin therapy in those with AGT. However, fasting glucose increased in those with normal glucose tolerance. There was no change in either body weight or insulin levels with spironolactone. But, there was a significant reduction in both the 0 and 2 h glucose with spironolactone also in those with AGT. Conclusion: Spironolactone and metformin had similar effect in reducing the glucose levels in PCOS patients with AGT. PCOS patients with normal glucose tolerance had higher fasting plasma glucose at the end of 6 months of metformin therapy inspite of weight reduction.     

Distribution of Putative Virulence Genes and Antimicrobial Drug Resistance in <Emphasis Type="Italic">Vibrio harveyi</Emphasis>

The marine-estuarine bacterium Vibrio harveyi is an important pathogen of invertebrates, most significantly, the larvae of commercially important shrimp Penaeus monodon. In this study, we analyzed V. harveyi isolated from shrimp hatchery environments for understanding the distribution of putative virulence genes and antimicrobial drug resistance. The putative genes targeted for PCR detection included four reversible toxin (Rtx)/hemolysin genes, a gene encoding homologue of Vibrio cholerae zonula occludens toxin (Zot) and a hemolysin-coregulated protein gene (hcp) by polymerase chain reaction (PCR). Of the four putative reversible toxin genes, vhh-1 was detected in 31% of the isolates, vhh-2 in 46%, vhh-3 in 23% and vhh-4 was detected in 27% of the isolates. A zot-like sequence of bacteriophage f237 was present in 15%, while hcp sequence was detected in 48% of the isolates. The antimicrobial susceptibility test revealed resistance to several groups of antibiotics including β-lactams, cephalosporins, macrolides, quinolones, nitrofurantoin and tetracycline.     

A study on the effects of some laboratory-derived genetic mutations on biofilm formation by Listeria monocytogenes

Biofilms formed by the human pathogen Listeria monocytogenes in food-processing environments can be a potential source of contamination. In this study, we investigated the ability of L. monocytogenes wild type and its laboratory-derived isogenic mutants in cwhA, prfA, agrA, flaA, degU, ami and sigB to adhere to and form biofilms on abiotic surfaces. The results suggest that inactivation of the two component regulatory system degU completely abolished biofilm formation, while inactivation of the flagellar gene flaA, two component response regulator agrA and the autolysin-adhesin gene ami lead to severe impairment of initial attachment and the subsequent development of a mature biofilm by L. monocytogenes. Mutants in the global regulator of virulence prfA and the alternative sigma factor sigB were unaffected and formed biofilms similar to wild type L. monocytogenes.     

Legacies in Switchgrass Resistance to and Recovery from Drought Suggest That Good Years Can Sustain Plants Through Bad Years

The warm-season perennial switchgrass (Panicum virgatum) is a candidate bioenergy crop. To be successful, switchgrass production must be maintained on low-quality landscapes with minimal inputs while facing future climates that are expected to be more extreme and more variable. We propose that antecedent rainfall constrains how plants respond to drought, as well as subsequently recover from drought. To test this idea, we examined how six switchgrass genotypes responded to a 1-year severe drought and then recovered under normal rainfall in the following year. These plants had previously grown for 3 years under a range of dry to wet rainfall levels in a shallow-soil common garden with no fertilizer. Plants previously exposed to drought produced less biomass, and basal area after the severe drought was relieved compared to previously well-watered plants. In addition, there were legacy effects caused by plant size: plants that were larger pre-drought were more likely to survive the severe drought, and plants that were larger during the severe drought recovered more biomass, basal area, and tillers post-drought. Although genotypes differed somewhat in their responses, the size constraint was consistent across genotypes. These findings suggest that we can establish more drought-resilient switchgrass stands by, for example, planning for initial irrigation or planting during a wet year to allow plants to grow larger prior to experiencing drought. Additional studies are needed to understand whether these rainfall and size legacies persist or are transient.     

Effect of slice thickness on brain magnetic resonance image texture analysis

Background  

The accuracy of texture analysis in clinical evaluation of magnetic resonance images depends considerably on imaging arrangements and various image quality parameters. In this paper, we study the effect of slice thickness on brain tissue texture analysis using a statistical approach and classification of T1-weighted images of clinically confirmed multiple sclerosis patients.     

Ecoepidemiology,short history and control of Chagas disease in the endemic countries and the new challenge for non-endemic countries

Chagas disease is maintained in nature through the interchange of three cycles: the wild, peridomestic and domestic cycles. The wild cycle, which is enzootic, has existed for millions of years maintained between triatomines and wild mammals. Human infection was only detected in mummies from 4,000-9,000 years ago, before the discovery of the disease by Carlos Chagas in 1909. With the beginning of deforestation in the Americas, two-three centuries ago for the expansion of agriculture and livestock rearing, wild mammals, which had been the food source for triatomines, were removed and new food sources started to appear in peridomestic areas: chicken coops, corrals and pigsties. Some accidental human cases could also have occurred prior to the triatomines in peridomestic areas. Thus, triatomines progressively penetrated households and formed the domestic cycle of Chagas disease. A new epidemiological, economic and social problem has been created through the globalisation of Chagas disease, due to legal and illegal migration of individuals infected by Trypanosoma cruzi or presenting Chagas disease in its varied clinical forms, from endemic countries in Latin America to non-endemic countries in North America, Europe, Asia and Oceania, particularly to the United States of America and Spain. The main objective of the present paper was to present a general view of the interchanges between the wild, peridomestic and domestic cycles of the disease, the development of T. cruzi among triatomine, their domiciliation and control initiatives, the characteristics of the disease in countries in the Americas and the problem of migration to non-endemic countries.     

Study of the occurrence of Vibrio vulnificus in oysters in India by polymerase chain reaction (PCR) and heterogeneity among V. vulnificus by randomly amplified polymorphic DNA PCR and gyrB sequence analysis

The pathogenic bacterium Vibrio vulnificus is widely distributed in estuarine waters throughout the world. In this study, the presence of V. vulnificus in oysters was studied both by conventional culture and DNA-based molecular technique. Following enrichment in alkaline peptone water (APW), the bacteria were lysed and a nested polymerase chain reaction (PCR) for vvhA gene was performed. The effect of duration of enrichment on the sensitivity of detection by PCR was evaluated. The organism was isolated from 43% of samples after 18 h enrichment in APW by conventional culture method. Nested PCR amplifying a fragment of vvhA gene detected the organism in 11%, 60% and 81% of samples following 0, 6 and 18 h of enrichment. All the biochemically identified V. vulnificus strains possessed vvhA gene and belonged to biotype 1. The genetic relatedness among the strains was studied by randomly amplified polymorphic DNA (RAPD) PCR and gyrB sequence analysis. The results suggest the presence of two distinct clonal groups of V. vulnificus in oysters in India. The study demonstrates, for the first time that gyrB sequence analysis could be used to study the genetic diversity of V. vulnificus.