Nonobese diabetic mice,hypoglycaemia and liver necrosis: a case report

This study investigates a case in a type I diabetic animal model, using nonobese diabetic mice, affected with hypoglycaemia and liver necrosis with other symptomatic complications. This particular animal was markedly different from other animals in the colony, and the investigations we carried out diagnosed various conditions such as growth retardation, frank diabetes, hypoinsulinaemia, hypoglycaemia and multiple foci liver necrosis with nucleomegaly. From the differential diagnosis, we hypothesize that this abnormality might be due to carbohydrate metabolic deficiency giving rise to diabetes and liver necrosis. We postulate that in these conditions, the liver controls the pancreas and that the liver should be the key target organ to control diabetes coupled with hypoglycaemia. Further investigations into the relationship between the carbohydrate metabolism, liver failure and overt diabetes in nonobese diabetic (NOD) animal models might have relevance to human disease.     

Klebsiella pneumoniae Carbapenemase-producing Enterobacteria in Hospital, Singapore

TO THE EDITOR: During the past decade, enterobacteria that produce Klebsiella pneumoniae carbapenemase (KPC) have become established in the United States and countries in South America and Europe (1). In Asia, KPC was reported in the People's Republic of China in 2007 (2) and subsequently in South Korea (3) and Taiwan (4). Public health agencies emphasize screening and strict contact precautions to control multidrug resistant Enterobacteriaceae (5). Routine testing for mechanisms of resistance facilitates detection of emerging carbapenem-resistant Enterobacteriaceae.     

Structural and mechanical profiles of native collagen fibers in vaginal wall connective tissues

Collagen, an ubiquitous biomaterial, confers robustness and resilience to connective tissues. In this study, we analyzed the structure and elasticity profile of collagen from the vaginal wall connective tissue of healthy pre-menopausal (pre-M) and postmenopausal (post-M) women. The histological staining assisted study with an atomic force microscope renders the examination of native collagen fibers on site of the connective tissue from nanoscopic scale to microscopic scale with high spatial resolution. Our results suggest that during menopause, collagen’s structure and elasticity are subject to changes at all levels of organization- between individual collagen fibers, between collagen and muscle, and between collagen and other matrix elements. The systematic analysis of the native structure and mechanical properties of collagen within a tissue provides a potential way to study non-fatal conditions such as pelvic organ prolapse and other genito-urinary disorders, where the initial symptoms are subtle and multivariate, and where early detection of patient’s condition may allow better non-invasive interventions and reduce the number of women undergoing surgical correction of these common disorders.     

Oral epithelial cells transplanted on to corneal surface tend to adapt to the ocular phenotype

To understand the response of oral epithelial cells, transplanted on corneal surface to the ocular cues in vivo. The corneal button obtained after penetrating keratoplasty (PK) of an eye of a patient with total limbal stem cell deficiency (LSCD), previously treated with cultured oral mucosal epithelial transplantation (COMET) was examined by immunohistochemistry for the expression of keratins, p63, p75, PAX6, Ki-67, CD31, and CD34. COMET followed by optical-PK has improved visual acuity to 20/40 and rendered a stable ocular surface. The excised corneal tissue showed the presence of stratified epithelium with vasculatures. The epithelial cells of the corneal button expressed K3, K19, Ki-67, p63, p75 and the cornea-specific PAX6 and K12. This study confirms that the oral cells, transplanted to corneal surface, survive and stably reconstruct the ocular surface. They maintain their stemness at the ectopic site and acquire some of the corneal epithelial-like characters.     

Geographical Information Systems: A Tool to Map and Analyze Disease Spread

Objective

Use GIS to illustrate and understand the association between environmental factors and spread of infectious diseases.

Introduction

Spatial methods are an important component of epidemiological research motivated by a strong correlation between disease spread and ecological factors (1). Our case studies examine the relationship between environmental conditions, such as climate and location, and vector distribution and abundance. Therefore, GIS can be used as a platform for integrating local environmental and meteorological variables into the analysis of disease spread, which would help in surveillance and decision making.

Methods

Case study 1- Lyme disease -Lyme disease is a tickborne infection caused by the bacterium Borrelia burgdorferi. The goal of this study was to analyze the association between meteorological factors and Lyme disease risk in humans in Texas. A total of 1,212 cases reported from 138 counties in Texas from Jan 2000 to Dec 2010 were analyzed. We used temperature and precipitation raster grids to generate humidity maps for Texas region. Our results indicated that there is a strong positive association between Lyme disease incidence and humidity, with western cross timbers region having a higher risk then the low plains.Case study 2- Spinach – Motivated by the recent increase in food-borne outbreaks related to fresh produce, one of the objectives for this study was to use the geospatial analysis to elucidate factors that contribute to contamination of produce at preharvest. We collected 955 spinach samples from 13 produce farms in Colorado and Texas during 2010–2011 and tested the samples for Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella contamination. The spinach contamination results were then used in conjunction with the National Resource Information (NRI) databases along with the SSURGO database to predict environmental and meteorological factors contributing to spinach contamination. Our findings would help to reduce frequency of human foodborne illnesses related to fresh produce.Case study 3- Valley fever Coccidioidomycosis or Valley Fever (VF) is a fungal zoonosis affecting humans and a variety of animal species. In this study, we used Texas Veterinary Medical Diagnostic Laboratories (TVMDL) data of all dog sera tested for coccidioidomycosis from July 1999 - December 2009. Census data on human population density for Texas were used to determine the dog population density and identify disease clusters for the 5,871 submitted dog sera over a period of 10.5 years. Both the isopleth map of the VF seropositive rates in dogs across Texas and the identified spatial and spatio-temporal clusters of the disease suggested that VF occurs in the western and southwestern part of Texas at a much higher rate than in other areas of the state (2). Since VF is not a reportable disease in TX, dogs could be used as a sentinel for human infection.

Results

The above studies illustrate the utility of GIS as a tool in integrating different ecological factors to understand disease occurrence and spread. The geographical and temporal patterns found in these studies provide benchmark to support disease control activities in Texas. Additionally, the identification of high-risk areas may be useful for decision makers to improve and prevent future disease spread.

Conclusions

Spatial epidemiological research has challenges, such as dealing with coarse level and aspatial datasets. Testing laboratories provide limited spatial information up to the zip code level due to the confidentiality concerns. Spatial analysis of such dataset prevents research at finer resolutions (Census block or block group). Despite these limitations, spatial epidemiology continues to be an invaluable field in the research and surveillance of infectious disease.