Determination of elemental composition of air particulates and soils in Khartoum area

Investigations were carried out for elemental composition of air particulates in the background air and near roadsides in Khartoum area. Investigations were also performed for the elemental composition of soils at the same locations. A cyclone and a dichotomous virtual impactor wereused to measure the air particulates. The cyclone was adjusted to collect particles having an aerodynamic diameter of 2.5!m. The virtual impactor, through its fine channel, was capable of collecting airborne particles with an aerodynamic diameter of 2.5 μm. Energy Dispersive X-Ray Fluorescence (EDXRF) analysis was used to study the elemental concentrations of the air and soil samples. The analysis of the results indicated that all elements in the proximity of roadsides have elevated concentrations compared to the background air levels. Enrichment factors were calculated relative to crust rock and Khartoum soil. The results showed that the elements K, Ca,Ti, Fe, and Sr in the aerosols have their origin from the soil, while the elements Zn, Ni and Pb have their source from automobile emissions. The results also indicated a correlation between lead and bromine. The lead to bromine ratio was found to be within the range of those derived from vehicular exhaust, and in good agreement with the ratios obtained from some other countries

The effect of maternal anthropometric characteristics and social factors on gestational age and birth weight in Sudanese newborn infants

<p>Abstract</p> <p>Background</p> <p>In Africa low birth weight (LBW) (<2500 g), is the strongest determinant of infant morbidity and mortality. The aim of this study was to quantify the effect of maternal anthropometry, education and socio-economic status on gestational age and birth weight.</p> <p>Methods</p> <p>In 1000 Sudanese mothers with singleton births, anthropometric measurements (weight, height, mid-arm circumference) and newborn birth weight were taken within 24 hours of delivery. Furthermore, maternal education and socio-economic status were recorded. The effect of these maternal variables on gestational age and birth weight was investigated by receiver operating characteristic (ROC) curves and by multivariate logistic regression analysis.</p> <p>Results</p> <p>Although maternal height was significantly correlated (p = 0.002) with gestational age, we did not find maternal characteristics of value in determining the risk for preterm birth. Birth order was the strongest determinant of birth weight compared to other maternal characteristics. The LBW rate of first born babies of 12.2% was nearly twice that of infants of multiparous mothers. Maternal age and all maternal anthropometric measurements were positively correlated (p < 0.001) with birth weight. A maternal height of <156 cm, a maternal weight of <66 kg, a maternal mid arm circumference of <27 cm and years of education of ≤ 8 years were found to increase the relative risk of LBW but this was statistically significant only in the case of maternal height. Maternal age and BMI had no statistically significant effect on determining the risk for LBW. The social class did not affect the birth weight, while the number of years of education was positively correlated with birth weight (p = 0.01). The LBW rate decreased from 9.2% for ≤ 8 years of education to 6.0% for >12 years of education.</p> <p>Conclusion</p> <p>Birth order and maternal height were found to be the most important maternal parameters which influences birth weight and the risk for LBW. The duration of maternal education and not social class was found to significantly affect the risk for LBW.</p

Detection of the pancreas-specific gene in the peripheral blood of patients with pancreatic carcinoma

The prognosis of patients with pancreatic carcinoma remains very poor. To improve the therapeutic results, the early detection of this cancer is needed. The present study was performed to detect the pancreas-specific gene, chymotrypsinogen, in the peripheral blood from patients with pancreatic carcinoma by using reverse transcription polymerase chain reaction (RT-PCR) in order to evaluate the clinical significance of this gene. Ten patients with pancreatic carcinoma, two with acute pancreatitis, three with chronic pancreatitis and ten control subjects were examined for the presence of chymotrypsinogen using RT-PCR techniques in the peripheral blood. To confirm that the chymotrypsinogen gene was expressed in a pancreas-specific manner, the expression of chymotrypsinogen in various types of human adult tissue was evaluated by RT-PCR. The specific band of the chymotrypsinogen gene was detected in the pancreas. Serial dilution studies demonstrated the chymotrypsinogen gene to be detected at a concentration of one pancreatic cell per 106 peripheral blood cells. Seven out of the ten (70%) patients with pancreatic carcinoma were found to be positive based on the RT-PCR findings. In contrast, no pancreas-specific gene was detected in the peripheral blood of any patients with acute pancreatitis, chronic pancreatitis or the control subjects. Our observations show that the detection of the pancreatic specific gene, chymotrypsinogen, is therefore useful as a genetic diagnostic marker in pancreatic carcinoma. © 1999 Cancer Research Campaig

Gene expression of circulating tumour cells in breast cancer patients

<p>Abstract</p> <p>Background</p> <p>The diagnostic tools to predict the prognosis in patients suffering from breast cancer (BC) need further improvements. New technological achievements like the gene profiling of circulating tumour cells (CTC) could help identify new prognostic markers in the clinical setting. Furthermore, gene expression patterns of CTC might provide important informations on the mechanisms of tumour cell metastasation.</p> <p>Materials and methods</p> <p>We performed realtime-PCR and multiplex-PCR analyses following immunomagnetic separation of CTC. Peripheral blood (PB) samples of 63 patients with breast cancer of various stages were analyzed and compared to a control group of 14 healthy individuals. After reverse-transcription, we performed multiplex PCR using primers for the genes <it>ga733.3, muc-1 </it>and <it>c-erbB2. Mammaglobin1, spdef </it>and <it>c-erbB2 </it>were analyzed applying realtime-PCR.</p> <p>Results</p> <p><it>ga733.2 </it>overexpression was found in 12.7% of breast cancer cases, <it>muc-1 </it>in 15.9%, <it>mgb1 </it>in 9.1% and <it>spdef </it>in 12.1%. In this study, <it>c-erbB2 </it>did not show any significant correlation to BC, possibly due to a highly ambient expression. Besides single gene analyses, gene profiles were additionally evaluated. Highly significant correlations to BC were found in single gene analyses of <it>ga733.2 </it>and <it>muc-1 </it>and in gene profile analyses of <it>ga733.3</it>*<it>muc-1 </it>and GA7 <it>ga733.3</it>*muc-1*<it>mgb1</it>*<it>spdef</it>.</p> <p>Conclusion</p> <p>Our study reveals that the single genes <it>ga733.3, muc-1 </it>and the gene profiles <it>ga733.3</it>*<it>muc-1 </it>and <it>ga733.3</it>*3<it>muc-1</it>*<it>mgb1</it>*<it>spdef </it>can serve as markers for the detection of CTC in BC. The multigene analyses found highly positive levels in BC patients. Our study indicates that not single gene analyses but subtle patterns of multiple genes lead to rising accuracy and low loss of specificity in detection of breast cancer cases.</p

Methylated APC and GSTP1 genes in serum DNA correlate with the presence of circulating blood tumor cells and are associated with a more aggressive and advanced breast cancer disease

<p>Abstract</p> <p>Background</p> <p>Tumor-related methylated DNA and circulating tumor cells (CTC) in the peripheral blood might be of prognostic importance in breast cancer. Thus, the aim of our study was to examine free methylated DNA and CTC in the blood from breast cancer patients and to correlate it with clinicopathological features known to influence prognosis.</p> <p>Materials and methods</p> <p>We prospectively obtained serum samples from 85 patients with breast cancer and 22 healthy volunteers. Sera were analysed by methylation specific PCR (MethyLight PCR) for five genes: adenomatous polyposis coli (APC), ras association domain family protein 1A (RASSF1A), estrogen receptor 1 (ESR1), CDKN2A (p16) and glutathione s-transferase pi 1 (GSTP1). Beta actin (ACTB) served as control. In parallel matched peripheral blood of 63 patients was used to assay for circulating tumor cells in the peripheral blood by a modified immunomagnetic AdnaTest BreastCancerSelect with PCR detection for EPCAM, MUC1, MGB1 and SPDEF.</p> <p>Results</p> <p>We found a hypermethylation in the APC gene in 29% (25/85), in RASSF1A in 26% (22/85), in GSTP1 in 18% (14/76) and in ESR1 in 38% (32/85) of all breast cancer patients. No hypermethylation of CDKN2A was found (0/25). Blood samples of patients were defined CTC positive by detecting the EPCAM 13% (8/63), MUC1 16% (10/63), MGB 9% (5/55), SPDEF 12% (7/58) and in 27% detecting one or more genes (15/55). A significant difference was seen in methylated APC DNA between cancer patients and healthy volunteers. Moreover, methylated APC, RASSF1 and CTC were significantly different in metastatic versus non-metastatic disease. In addition, the presence of methylated APC, RASSF1A and CTC correlated significantly with AJCC-staging (p = 0.001, p = 0.031 and 0.002, respectively). High incidences of methylations were found for the genes RASSF1 and ESR1 in healthy individuals (both 23% 5/22). Methylated GSTP1 was predominantly found in the serum of patients with large primaries (p = 0.023) and was highly significantly correlated with positive Her2/<it>neu </it>status (p = 0.003). Elevated serum CA15.3 was strongly correlated with methylated APC and CTC detection (both p = 0.000). Methylated ESR1 failed to exhibit significant correlations with any of the above mentioned parameters. The presence of CTC in peripheral blood was significantly associated with methylated APC (p = 0.012) and methylated GSTP1 (p = 0.001).</p> <p>Conclusion</p> <p>The detection of methylated APC and GSTP1 DNA in serum correlated with the presence of CTC in the blood of breast cancer patients. Both methylated DNA and CTC correlated with a more aggressive tumor biology and advanced disease.</p

Afternoon rain more likely over drier soils

Land surface properties, such as vegetation cover and soil moisture, influence the partitioning of radiative energy between latent and sensible heat fluxes in daytime hours. During dry periods, a soil-water deficit can limit evapotranspiration, leading to increased surface heating ofwarmer and drier conditions in the lower atmosphere and affecting the climate. Soil moisture can influence the development of convective storms through such modifications of low-level atmospheric temperature and humidity, which in turn feeds back on soil moisture. Yet there is considerable uncertainty in how soil moisture affects convective storms across the world, owing to a lack of observational evidence and uncertainty in large-scale models. Here we present a global-scale observational analysis of the coupling between soil moisture and precipitation. We show that across all six continents studied, afternoon rain falls preferentially over soils that are relatively dry compared to the surrounding area. The signal emerges most clearly in the observations over semi-arid regions, where surface fluxes are sensitive to soil moisture, and convective events are frequent. Mechanistically, our results are consistent with enhanced afternoon moist convection driven by increased sensible heat flux over drier soils, and/or mesoscale variability in soil moisture. We find no evidence in our analysis of a positive feedback—that is, a preference for rain over wetter soils—at the spatial scale (50–100 kilometres) studied. In contrast, we find that a positive feedback of soil moisture on simulated precipitation does dominate in six state-of-the-art global weather and climate models—a difference that may contribute to excessive simulated droughts in large-scale models

Incorporating the effects of humidity in a mechanistic model of Anopheles gambiae mosquito population dynamics in the Sahel region of Africa

Background: Low levels of relative humidity are known to decrease the lifespan of mosquitoes. However, most current models of malaria transmission do not account for the effects of relative humidity on mosquito survival. In the Sahel, where relative humidity drops to levels <20% for several months of the year, we expect relative humidity to play a significant role in shaping the seasonal profile of mosquito populations. Here, we present a new formulation for Anopheles gambiae sensu lato (s.l.) mosquito survival as a function of temperature and relative humidity and investigate the effect of humidity on simulated mosquito populations. Methods: Using existing observations on relationships between temperature, relative humidity and mosquito longevity, we developed a new equation for mosquito survival as a function of temperature and relative humidity. We collected simultaneous field observations on temperature, wind, relative humidity, and anopheline mosquito populations for two villages from the Sahel region of Africa, which are presented in this paper. We apply this equation to the environmental data and conduct numerical simulations of mosquito populations using the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS). Results: Relative humidity drops to levels that are uncomfortable for mosquitoes at the end of the rainy season. In one village, Banizoumbou, water pools dried up and interrupted mosquito breeding shortly after the end of the rainy season. In this case, relative humidity had little effect on the mosquito population. However, in the other village, Zindarou, the relatively shallow water table led to water pools that persisted several months beyond the end of the rainy season. In this case, the decrease in mosquito survival due to relative humidity improved the model's ability to reproduce the seasonal pattern of observed mosquito abundance. Conclusions: We proposed a new equation to describe Anopheles gambiae s.l. mosquito survival as a function of temperature and relative humidity. We demonstrated that relative humidity can play a significant role in mosquito population and malaria transmission dynamics. Future modeling work should account for these effects of relative humidity.National Science Foundation (U.S.) (Grant EAR-094628