120 research outputs found

    Dielectric properties measurements of brown and white adipose tissue in rats from 0.5 to 10 GHz

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    Brown adipose tissue (BAT) plays an important role in whole body metabolism and with appropriate stimulus could potentially mediate weight gain and insulin sensitivity. Although imaging techniques are available to detect subsurface BAT, there are currently no viable methods for continuous acquisition of BAT energy expenditure. Microwave (MW) radiometry is an emerging technology that allows the quantification of tissue temperature variations at depths of several centimeters. Such temperature differentials may be correlated with variations in metabolic rate, thus providing a quantitative approach to monitor BAT metabolism. In order to optimize MW radiometry, numerical and experimental phantoms with accurate dielectric properties are required to develop and calibrate radiometric sensors. Thus, we present for the first time, the characterization of relative permittivity and electrical conductivity of brown (BAT) and white (WAT) adipose tissues in rats across the MW range 0.5-10GHz. Measurements were carried out in situ and post mortem in six female rats of approximately 200g. A Cole-Cole model was used to fit the experimental data into a parametric model that describes the variation of dielectric properties as a function of frequency. Measurements confirm that the dielectric properties of BAT (εr = 14.0-19.4, σ = 0.3-3.3S/m) are significantly higher than those of WAT (εr = 9.1-11.9, σ = 0.1-1.9S/m), in accordance with the higher water content of BAT

    A pilot double-blind randomised placebo-controlled trial of the effects of fixed-dose combination therapy ('polypill') on cardiovascular risk factors

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    SummaryAim: Our objective was to investigate the effects and tolerability of fixed-dose combination therapy on blood pressure and LDL in adults without elevated blood pressure or lipid levels. Methods: This was a double-blind randomised placebo-controlled trial in residents of Kalaleh, Golestan, Iran. Following an 8-week placebo run-in period, 475 participants, aged 50 to 79 years, without cardiovascular disease, hypertension or hyperlipidaemia were randomised to fixed-dose combination therapy with aspirin 81 mg, enalapril 2.5 mg, atorvastatin 20 mg and hydrochlorothiazide 12.5 mg (polypill) or placebo for a period of 12 months. The primary outcomes were changes in LDL-cholesterol, systolic and diastolic blood pressure and adverse reactions. Analysis was by intention-to-treat basis. Results: At baseline, there were differences in systolic blood pressure (6 mmHg). Taking account of baseline differences, at 12 months, polypill was associated with statistically significant reductions in blood pressure (4.5/1.6 mmHg) and LDL-cholesterol (0.46 mmol/l). The study drug was well tolerated, but resulted in the modest reductions in blood pressure and lipid levels. Conclusion: The effects of the polypill on blood pressure and lipid levels were less than anticipated, raising questions about the reliability of the reported compliance. There is a case for a fully powered trial of a polypill for the prevention of cardiovascular disease. © 2010 Blackwell Publishing Ltd

    A Novel Compact Microwave Radiometric Sensor to Noninvasively Track Deep Tissue Thermal Profiles

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    Drawing from space technology to measure star temperature, we developed a noninvasive sensor to passively track thermal profiles in tissues well below the skin (\u3e5cm). Ultra-low noise amplifiers combined with ultralow-loss switches in the 1- 2GHz band produce a high sensitivity multiband microwave radiometer. Due to the complex multilayer anatomy of human head, multiple sensing bands are needed to reconstruct the temperature of deep brain tissue. This is achieved by using a digitally controlled filter bank. To study its accuracy, the sensor was calibrated and tested in a multilayer phantom model of the human head with differential scalp and brain temperatures. Results of phantom testing showed that calculated radiometric equivalent brain temperature agreed within 0.4°C of measured temperature when circulating homogenized brain phantom was lowered 10°C and returned to original temperature (37°C), while scalp was maintained constant over a 4.6-hour experiment. Feasibility of clinical monitoring was assessed in a pediatric patient during a hypothermic heart surgery. Over the 2-hour surgery, the radiometric sensor tracked within 1°C of rectal and nasopharynx temperatures, except during rapid cooldown and heatup periods when brain temperature deviated 2-4°C from slower responding core temperature surrogates. In summary, the sensor demonstrated long term stability and sensitivity sufficient for accurate monitoring of volume average brain temperatur

    Germline BRCA2 mutations and the risk of esophageal squamous cell carcinoma

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    The incidence of esophageal squamous cell carcinoma (ESCC) is very high among the Turkmen population of Iran. Family studies suggest a genetic component to the disease. Turkmen are ethnically homogenous and are well suited for genetic studies. A previous study from China suggested that BRCA2 might play a role in the etiology of ESCC. We screened for mutations in the coding region of the BRCA2 gene in the germline DNA of 197 Turkmen patients with ESCC. A nonsense variant, K3326X, was identified in 9 of 197 cases (4.6) vs 2 of 254 controls (0.8) (OR=6.0, 95 CI=1.3-28; P=0.01). This mutation leads to the loss of the C-terminal domain of the BRCA2 protein, a part of the region of interaction with the FANCD2 protein. We observed nine other BRCA2 variants in single cases only, including two deletions, and seven missense mutations. Six of these were judged to be pathogenic. In total, a suspicious deleterious BRCA2 variant was identified in 15 of 197 ESCC cases (7.6). © 2008 Nature Publishing Group All rights reserved

    Association of C677T (rs1081133) and A1298C (rs1801131) Methylenetetrahydrofolate Reductase Variants with Breast Cancer Susceptibility Among Asians: A Systematic Review and Meta-Analysis

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    This systematic review and meta-analysis were conducted to investigate the association between methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms with breast cancer (BC) in Asians. Systematic searches were conducted in PubMed, EMBASE, Web of Science, and Scopus by May 2020. Inter-study heterogeneity was also assessed with a Q test, along with I2 statistics. Random-effects models were applied to pooled crude ORs with corresponding 95% CIs for the genetic models. A total of 1097 identified results, along with 36 qualified studies were included: for MTHFR C677T polymorphism, a total of 36 studies was comprised of 11,261 cases and 13,318 controls and for MTHFR A1298C polymorphism, a number of 19 studies contained 7424 cases and 8204 controls. Likewise, for C677T polymorphism, an increased risk of BC was seen for the allelic (OR 1.21, 95% CI 1.09–1.33, P < 0.01, I2 = 78.9%), dominant (OR 1.17, 95% CI 1.05–1.30, P < 0.01, I2 = 71.8%), recessive (OR 1.43, 95% CI 1.23–1.67, P < 0.01, I2 = 55.8%), and homozygous models (OR 1.48, 95% CI 1.25–1.75, P < 0.01, I2 59.9%) among BC patients compared to controls. Also, in terms of A1298C polymorphism, an association was found between the allelic (OR 1.15, 95% CI 1.04–1.28, P < 0.01, I2 70.4%) and homozygous models (OR 1.38, 95% CI 1.15–1.66, P < 0.01, I2 44.2%) with the risk of BC. In conclusion, findings revealed that MTHFR C677T variant might be a factor that predisposes BC in Asians. Furthermore, it was found that A1298C variant acts as a BC risk factor, particularly in a Western Asia population

    Validity and reliability of a new food frequency questionnaire compared to 24h recalls and biochemical measurements: Pilot phase of Golestan cohort study of esophageal cancer

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    Background: A pilot study was carried out to evaluate validity and reproducibility of a food frequency questionnaire (FFQ), which was designed to be used in a prospective cohort study in a population at high risk for esophageal cancer in northern Iran. Methods: The FFQ was administered four times to 131 subjects, aged 35-65 years, of both sexes. Twelve 24-h dietary recalls for two consecutive days were administered monthly during 1 year and used as a reference method. The excretion of nitrogen was measured on four 24-h urine samples, and plasma levels of β-carotene, retinol, vitamin C and α-tocopherol was measured from two time points. Relative validity of FFQ and 24-h diet recall was assessed by comparing nutrient intake derived from both methods with the urinary nitrogen and plasma levels of β-carotene, retinol, vitamin C and α-tocopherol. Results: Correlation coefficients comparing energy and nutrients intake based on the mean of the four FFQ and the mean of twelve 24-h diet recalls were 0.75 for total energy, 0.75 for carbohydrates, 0.76 for proteins and 0.65 for fat. Correlation coefficients between the FFQ-based intake and serum levels of β-carotene, retinol, vitamin C and vitamin E/α-tocopherol were 0.37, 0.32, 0.35 and 0.06, respectively. Correlation coefficients between urinary nitrogen and FFQ-based protein intake ranged from 0.23 to 0.35. Intraclass correlation coefficients used to measure reproducibility of FFQ ranged from 0.66 to 0.89. Conclusion: We found that the FFQ provides valid and reliable measurements of habitual intake for energy and most of the nutrients studied. © 2006 Nature Publishing Group. All rights reserved

    Tychiini and Mecinini (Coleoptera: Curculionidae, Curculioninae) of Iran: eleven species recorded for the first time, with new data on host plants and distribution of several species

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    A faunistic study on the tribes Tychiini and Mecinini (Curculionidae, Curculioninae) was carried out during the years 2010-2013 in different ecological regions of Iran. Twenty nine species belonging to the genera Mecinus Germar, 1821, Gymnetron Schoenherr, 1825, Rhinusa Stephens, 1829, Cleopomiarus Pierce, 1919, Tychius Germar, 1817 and Sibinia Germar, 1817 were collected. Localities and ecological notes on each species are provided. Among these, The following 11 species are new to the Iranian fauna: Mecinus crassifemur (Arzanov, 1991), Mecinus simus (Mulsant & Rey, 1859), Gymnetron linkei Reitter, 1907, Rhinusa antirrhini (Paykull, 1800), Rhinusa brondelii (H. Brisout de Barneville, 1862), Rhinusa florum (Rübsaamen, 1895), Tychius reitteri Faust, 1889, Tychius tridentinus Penecke, 1922, Sibinia aureofulva (Desbrochers des Loges, 1875), Sibinia pellucens (Scopoli, 1772), Sibinia unicolor Fảhraeus, 1843, whereas all other 18 species are new for one or more provinces. Host plants of several species reported for the first time and commented as well

    Evaluation of sperm quality and different nutrient levels on sperm efficiency in male rainbow trout

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    Considering the importance of rainbow trout (Oncorhynchus mykiss) in supplying required protein of people and effort to increase the efficiency of these fish reproduction, some related factors such as sperm quality and potential fertility of male are necessary. The aim of this study was to find out the effects of different dosages of Arginine on the biochemical parameters (including LDH, AST, ALT, ALP, iron, magnesium, phosphorous, chloride, calcium, sodium, Potassium, cholesterol, uric acid, urea, fructose, glucose, total protein and pH) of rainbow trout seminal plasma. For this purpose, five practical diets (each consisting of 3 triplicates) were supplemented with Arginine at 0.00 (Control), 0.50, 1.00, 1.50 and 2.00%. Broodstock feed last for 90 days. At the end of the feeding period one fish was captured from each replicate in order to collect their semen. Results indicate that there were no significant differences in LDH, ALP, Fe^2+ and P content among different treatments. The lowest level of AST and ALT and the highest level of Ca^2+ and Mg^2+ ions were observed in the treatment fed with 1.50% of Arginine which showed significant differences with other treatments (p<0.05). Moreover, the amount of Cl^-, Na^+ and K^+ ions were significantly increased in the seminal plasma in fish which were fed on diets containing arginine in comparison to control. As the amount of Arginine were increased, the levels of uric acid stepped up significantly in contrast to the urea and glucose. The highest amounts of cholesterol, fructose and total protein were observed in the treatments fed on 2.00, 0.50 and 1.00% of Arginine, respectively, that showed significant differences with other treatments (p<0.05). The highest pH value was assayed in the 1.50% of Arginine treatment. The results of the Pearson correlation coefficient showed a significant positive correlation between Ca^2+ and Mg^2+ ions and Na^+ with K^+ and Clions (r=0.750, r=0.769 and r= 0.938, p<0.01), respectively. On the other hand, a significant negative correlation between cholesterol with Cl^-, Na^+, K^+, ALT and LDH (r=- 0.764, r=-0.724 and r=-0.728, p<0.01) and (r=-0.531 and r=-0.560, p<0.05) and also a significant positive correlation between K^+ and Clions (r=0.836, p<0.01) were observed. Finally, it can be expressed that the levels of most of the ions were increased and there was a reduction in the levels of enzymes in seminal plasma of fish which were fed with practical diet including 1.5% of Arginine. So it can be recommended that adding this value of Arginine to the diets of rainbow trout broodstock, would improve the sperm quality which results in the enhancement of efficiency in rainbow trout reproduction
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