Arsenic exposure and young adult's mortality risk: A 13-year follow-up study in Matlab, Bangladesh.

BACKGROUND: Widespread arsenic contamination in underground water is a well-documented public health concern that threatens millions of lives worldwide. We investigated the risk of young-adult mortality due to high chronic exposure to arsenic through years of drinking arsenic contaminated water. METHODS: A prospective cohort study of 58,406 individuals was enrolled who were 4-18 years at baseline. Since Matlab HDSS (Health and Demographic Surveillance System) has an active surveillance system, all individuals were included in the follow up. Each individual's arsenic exposure was calculated at (1) baseline As level as current exposure (2) time-weighted lifetime (average or lifetime average) and (3) cumulative arsenic exposure. Age, sex, educational attainment and SES were adjusted during the analysis. In this 13 years closed-cohort study (2003-2015), all young-adult deaths were captured through verbal autopsy (VA) using International Classification of Diseases (ICD-10) to define the causes. RESULTS: Although, girls had higher values of cumulative arsenic exposure via tube well water than boys (median: 1858.5 µg/year/L vs. 1798.8 µg/year/L) but higher mortality due to cancers and due to cerebro-vascular disease, cardio-vascular disease, and respiratory disease (7.0 vs. 5.7 per 100,000 person-years and 6.4 vs. 4.2 per 100,000 person-years respectively). Higher risk of deaths among young adults (Adjusted HR: 2.7, 1.3-5.8) due to all cancers among those who were exposed to As > 138.7 compared to As ≤ 1.1 µg/L. For cerebro-vascular disease, cardio-vascular disease, and respiratory disease deaths, average arsenic in well water (>223.1 µg/L vs. ≤90.9 µg/L) and cumulative arsenic in well water (>2711.0 µg/year/L vs. ≤1013.3 µg/year/L) had 4.8 (1.8-12.8) and 5.1 (1.7-15.1) times higher risks of mortality than to those lowest exposed. CONCLUSION: Higher concentration of, and chronic exposure to arsenic in drinking water, increases the mortality risk among the young adults, regardless of gender.

Waveguide evanescent field scattering microscopy: bacterial biofilms and their sterilization response via UV irradiation.

Waveguide Evanescent Field Scattering (WEFS) microscopy is introduced as a new and simple tool for label-free, high contrast imaging of bacteria and bacteria sensors. Bacterial microcolonies and single bacteria were discriminated both by their bright field images and by their evanescent scattering intensity. By comparing bright field images with WEFS images, the proportion of planktonic: sessile (i.e., "floating": attached) bacteria were measured. Bacteria were irradiated with UV light, which limited their biofilm forming capability. A quantitative decrease in attachment of individual, sessile bacteria and in attached, microcolony occupied areas was easily determined within the apparent biofilms with increasing UV dose. WEFS microscopy is an ideal tool for providing rapid quantitative data on biofilm formation.

Orientation distribution of highly oriented type I collagen deposited on flat samples with different geometries.

The structural arrangement of type I collagen in vivo is critical for the normal functioning of tissues, such as bone, cornea, tendons, and blood vessels. At present, there are no established low-cost techniques for fabricating aligned collagen structures for applications in regenerative medicine. Here, we report on a straightforward approach to fabricate collagen films, with defined orientation distributions of collagen fibrillar aggregates within a matrix of oriented collagen molecules on flat sample surfaces. Langmuir-Blodgett (LB) technology was used to deposit thin films of oriented type I collagen onto flat substrates exhibiting various shapes. By varying the shapes of the substrates (e.g., rectangles, squares, circles, parallelograms, and various shaped triangles) as well as their sizes, a systematic study on collagen alignment patterns was conducted. It was found that the orientation and the orientation distribution of collagen along these various shaped substrates are directly depending on the geometry of the substrate and the dipping direction of that sample with respect to the collagen/water subphase. An important factor in tissue engineering is the stability, durability, and endurance of the constructed artificial tissue and thus its functioning in regenerative medicine applications. By testing these criteria, we found that the coated films and their alignments were stable for at least three months under different conditions and, moreover, that these films can withstand temperatures of up to 60 °C for a short time. Therefore, these constructs may have widespread applicability in the engineering of collagen-rich tissues.

Insulin secretion and sensitivity in Bangladeshi prediabetic subjects.

OBJECTIVE: There are still considerable controversies regarding the basic pathophysiological mechanisms of impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT). The present study was undertaken to explore the beta-cell function and insulin sensitivity in a Bangladeshi prediabetic population. METHODS: Twenty-four IFG and 112 IGT subjects, along with 40 healthy controls, were selected purposively following 2003 ADA cut-off values and 2006 WHO/IDF grouping. IGT subjects were subcategorized into 53 isolated IGT (I-IGT) and 59 combined IFG-IGT subjects. Plasma glucose and insulin (by chemiluminescent immunoassay) were measured at fasting and 2 h after 75 g of oral glucose load. Insulin sensitivity was assessed by homeostasis model assessment (HOMA-S%) and insulin sensitivity index for glycemia (ISI(gly)) and insulin secretion by HOMA-B%. RESULTS: Compared to control, fasting and 2-h plasma insulin were higher in I-IGT and IFG-IGT subjects; similarly, HOMA-S% [median (range)] was lower in I-IGT and IFG-IGT subjects [116 (54-227) vs. 93 (23-187) and 79 (32-197)%, P<.05 and P<.001]; ISI(gly) was also lower in I-IGT and IFG-IGT subjects [0.95 (0.54-1.64) vs. 0.64 (0.26-1.24) and 0.65 (0.29-1.20), P<.001]. But HOMA-B% was compromised in IFG and IFG-IGT groups [88 (59-182) vs. 68 (37-107) and 74 (36-141)%, P<.001 and P<.05]. The IGT group (combination of I-IGT and IFG-IGT) showed higher fasting and 2-h insulin, and lower HOMA-S% as well as ISI(gly), but compromised HOMA-B% was not evident. CONCLUSIONS: The pathophysiological mechanisms differ in IFG (having B-cell dysfunction) and I-IGT (an insulin-resistant condition). The pathophysiology of IFG-IGT (having both B-cell dysfunction and insulin resistance) indicates that it may be a different entity and not be included in IGT.