Dependence of descriptors of co-localization on microscope spatiotemporal resolution and the choice of regions of interest

Abstract

The advent and increasing availability of super-resolution microscopies has prompted re-searchers to re-investigate questions of co-localization and co-clustering in the hope of providing more precise and relevant data. Here, we focus on the problem of studying inter-organelle interfaces, a topic of growing interest in cell biology. We sought to identify mitochondria-associated membrane (MAM) candidate sites from dual-colour large-field super-resolution images. MAMs are specialized lipid microdomains of the endoplasmic reticulum (ER) in close apposition with mitochondria. Using total internal reflection fluorescence structured-illumination microscopy (TIRF-SIM, Brunstein et al., Optics Express, 2013), we achieved a three-dimensional spatial resolution down to ∼100 nm. Based on experimental and simulated data, we studied how the spatio-temporal resolution affects common descriptors of co-localization. The apparent overlap scaled inversely with spatial resolution (as expected for objects that are in close apposition and do not merge), independently of the precise metrics used. Important for live-cell imaging, organelle motility made measurements more uncertain, rendering statements of how physiological stimulations or pharmacologic manipulations affect co-localization less robust. Organelle density, or equivalent, the choice of different subcellular regions of interest (ROIs) had a marked effect on the amount of co-localization, as had the size of the ROI chosen. Our study calls for prudence when interpreting co-localization data and suggests that cell and organelle motility, the choice of the ROI analysed, the effective spatiotemporal resolution all impact on the result and hence should systematically be stated, particularly when co-localization arguments are used to assess the effect of drug application on cellular signalling pathways.

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Genotyping

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Study of blood pressure profile and correlation of hypertension with age, sex, anthropometric measurements (weight, height, body mass index), socio economic status and hereditary factors in school going children

2016-11-08T00-20-56Z
Source: International Journal of Contemporary Pediatrics
Kamatham Madhusudhan, Rajendra Betham, Venkateswara Rao Jampana.
Background: Pre hypertension in childhood is a precursor of hypertension in adulthood. Weight, height and body mass index (BMI) can be taken as surrogate marker of prevalence of hypertension and hence measurement of these parameters can help in early detection of children at risk of hypertension. The present study was done to determine the correlation of hypertension with age, gender, anthropometric measurements, socioeconomic status, and hereditary factors and to estimate the prevalence of hypertension and pre hypertension. Methods: It is an observational study involving 1009 healthy urban school children of 5 to 15 years of age. Height and weight were taken according to standard techniques (Jelliffee 1966). In order to exclude age as a confounding factor; BMI was plotted on percentile charts. Results: There was a linear increase of mean blood pressure with increasing age, height and weight. The mean systolic and diastolic blood pressures of children with BMI 85th to 95th percentile (overweight group) and with BMI ≥95th percentile (obese group) were higher than the lower BMI groups. The children belonging to high socio economic status (class I) and those with family history of hypertension were having higher mean values of systolic and diastolic blood pressure. Equal number of children belonged to pre hypertension (65) and hypertension (67) category. Conclusions: The mean systolic and diagnostic blood pressure was equal in both sexes. Children with overweight/obesity, family history of hypertension and class I socioeconomic status had increased mean values of systolic and diastolic blood pressure. Prevalence of high blood pressure was 13.1% (pre hypertension: 6.44% and hypertension: 6.64%).


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Prevalence and correlation of soil transmitted helminth infection to the degree of anemia and nutritional status among pediatric patients of age group 6-14 years in Kishanganj, Bihar, India

2016-11-08T00-20-56Z
Source: International Journal of Contemporary Pediatrics
Santosh Kumar, Jasninder Singh, Abhay Kumar.
Background: Intestinal parasites are a major public health problem in tropical and sub­tropical countries, affecting the physical growth and cognitive development in school age children. This study was conducted to estimate the prevalence of various helminthes, the symptomatology and clinical manifestations of various helminthes and to correlate the nutritional status with the type of helminthic infestation. Methods: Cross-sectional study involving children aged 6­14 years attending pediatric outpatient department in MGM Medical College, Kishanganj who were screened to estimate the prevalence of soil transmitted helminthes. Results: Out of the 500 children examined, 275 children were positive for one or other helminthic ova in the stool samples giving overall incidence of 55 %. Ascariasis was most common with 58.2% among all the positive cases, hookworm 7.3%, trichuris trichura 14.5%, hymenolepsis nana 3.6%, taenia saginata 1.8% while mixed infestations constitute 14.5%. There was no significant association of gender and infestation (p value >0.05). Patients on non-vegetarian diet were more prone to get infested (Chi- square value = 19.48, p value


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Numerical Study of Single Well Vapor Extraction Process

Vapor extraction (Vapex) is an emerging technology to produce heavy oil and bitumen from subsurface formations. Single well (SW) Vapex technique uses the same concept of Vapex process but only with one horizontal well. In this process solvent is injected from the toe of the horizontal well with oil production at the heel section. The main advantage of SW-Vapex process lies in the economic saving and applicability in problematic reservoirs, where drilling of two horizontal wells is impractical. The performance of SW-Vapex seems to be comparable with dual horizontal Vapex process using proper optimization schemes. This study is grouped into two sections: (i) a screening study of early time operating performance of SW-Vapex and (ii) a sensitivity analysis of the effect of the reservoir and well completion parameters. Simulation results show that solvent injection rate can be optimized to improve oil production rate. Higher injection rates may not necessarily lead to increase in production. This study confirms that SW-Vapex process is very ineffective in reservoirs with high oil viscosity (more than 1,500 cp) and thin formations (less than 10 m).

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