Genetic Association of Interleukin 16 Gene Polymorphisms (rs11556218 & rs4778889) with Type 1 Diabetes in Egyptian Children: A Case-Control Study.

BACKGROUND: Type 1 diabetes (T1D) is a serious chronic autoimmune condition. Even though the underlying reason for the onset of T1D is unknown, due to their effector and regulatory roles in immune responses, cytokines are essential in developing autoimmune disorders. Interleukin (IL)16 is an immunomodulatory cytokine implicated in several inflammatory and autoimmune diseases. OBJECTIVE: This study was designed to examine the association of IL16 gene polymorphisms, rs11556218 T > G and rs4778889 T > C, with the risk of T1D in Egyptian children. METHODS: Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay, we analyzed rs11556218 T > G and rs4778889 T > C polymorphisms of the IL16 gene in 100 T1D subjects and 93 controls. RESULTS: Rs11556218 T > G polymorphism of the IL16 gene was not associated with the risk of developing T1D. Analysis of IL16 gene rs4778889 T > C showed that the TT genotype had a considerably higher risk of T1D than the TC genotype [OR = 2.195 (1.205-3.999)]. In comparison to patients with the C allele [OR = 0.6914 (0.38-1.2569)], patients with the T allele [OR = 1.45 (0.7956-2.6296)] were notably more likely to have T1D. A significant decrease was found in the frequency of GT (OR = 0.43, p = .03) and TC (OR = 0.32, p = .011) haplotypes of IL16 gene rs11556218 T > G and rs4778889 T > C polymorphisms in T1D patients compared with controls. CONCLUSION: IL16 gene rs4778889 T > C polymorphism might be associated with susceptibility to T1D. Egyptians with TT genotypes are more likely to develop T1D. However, GT and TC haplotypes of IL16 gene rs11556218 T > G and rs4778889 T > C polymorphisms highlight their protective role againstT1D disease.

Changes on physicochemical and rheological properties of biscuits substituted with the peel and alcohol-insoluble solids (AIS) from cactus pear (Opuntia ficus-indica).

Cactus pear fruit consists of the peel, seeds and pulp. The peel is a major waste in cactus pear pulp based products accounting about 37.72% of the fruit weight. The aim of this study was to utilized and characterized the physicochemical and rheological properties of biscuits substituted with extracted cactus pear peel (CPP) and alcohol-insoluble solids (AIS) from cactus pear (Opuntia ficus-indica). To prepare AIS, peels were shredded and dropped in ethanol (70%) for 15 min. The mixture was boiled at 70 °C for 30 min, filtered and washed with ethanol 70% and the washing repeated until no sugars. The residue was washed and dried at room temperature. Changes in physiochemical and rheological properties of extracted CPP and AIS from cactus pear to qualify determine their use in the production of them to produce a fiber-rich food product. The water-holding capacity was 3.7 ml/g for the peel and 1.5 ml/g for the AIS, and the oil-holding capacity was approximately the same for both the CPP and AIS. The protein content was 3.5% for the CPP and 3.72% for the AIS. The CPP and AIS contained little fat (1.22% and 1.44%, respectively). Potassium and calcium in the AIS had the highest concentration, at 21.49 g/kg and 44.04 g/kg, respectively, and these minerals were found at 22.07 g/kg and 16.66 g/kg, respectively, in the CPP. The dominant phenolic compounds found in the CPP were pyrogallol, catechol, catechin, and alpha-coumaric acid. The results showed that the AIS contained pyrogallol (61.67 ppm), benzoic acid (10.68 ppm), vanillic acid (7.66 ppm), catechin (4.65 ppm) and salicylic acid (4.51 ppm). The CPP was rich in glucose (25.95%) and fructose (21.36%) compared to the AIS. The sensory evaluation indicated that 7.5% dried cactus pear peel or 7.5% AIS can be successfully used in substitution of wheat flour biscuits. It could be conducted cactus pear as major by-product can be important for the industrial utilization.

A Highly Sensitive and Selective Catalytic Determination of Mercury in Environmental Samples.

A simple, selective and highly sensitive spectrophotometric method has been developed for mercury determination utilizing its catalytic effect on the isoniazid-hexacyanoferrate (II) reaction. The paper presents for the first time (1) the catalytic effect of Hg (I) on the cited ligand substitution reactions and (2) the activating effect of thiourea on the behavior of mercury. The reaction was monitored spectrophotometrically at 423 nm using the initial rate method. The optimized reaction conditions were 5.0 mmol L(-1) hexacyanoferrate (II), 0.5 mmol L(-1) isoniazid, 150 mmol L(-1) citrate buffer (pH 3.30 ± 0.05), and 0.2 mmol L(-1) thiourea, at 50°C. Linear calibration graphs were obtained for 1-100 and 1-55 µg L(-1) with detection limits, based on the 3Sb-criterion, of 1.2 and 1.8 µg L(-1) of Hg (II) and Hg (I), respectively. The method was conveniently applied to samples of wastewaters, inactivated vaccines, and frozen Bass fish fillet, without any prior separation or preconcentration.

Expression of Concern: Solid-state dye-sensitized solar cells based on Zn1-xSnxO nanocomposite photoanodes.

Expression of Concern for 'Solid-state dye-sensitized solar cells based on Zn1-xSnxO nanocomposite photoanodes' by Ayat Nasr El-Shazly et al., RSC Adv., 2018,8, 24059-24067, DOI: https://doi.org/10.1039/c8ra02852d.

Bone morphogenic protein-7 (BMP-7) polymorphism: Susceptibility to cirrhosis and hepatocellular carcinoma after viral hepatitis in Egyptian patients.

Aim of the study: Bone morphogenic proteins (BMPs) have both inhibitory and stimulatory effects on growth of a tumor that depend on the type of cells, the dosage and the tumor microenvironment. We aimed to investigate the impact of the bone morphogenic protein-7 (BMP-7) single nucleotide polymorphism (SNP) rs230205 [A/G] on susceptibility to hepatocellular carcinoma (HCC) progression from liver cirrhosis after viral hepatitis infection in Egyptian patients. Material and methods: The amplification-refractory mutation system (ARMS)-polymerase chain reaction (PCR) method was used to genotype the rs230205 [A/G] SNP in 150 subjects (50 patients with post-hepatitis C or B cirrhosis, 50 HCC patients, and 50 controls). Expression level of BMP-7 protein was assessed using enzyme-linked immunosorbent assay (ELISA). Results: The results revealed insignificant changes in distribution of all genotypes/alleles of the BMP-7 rs230205 [A/G] SNP between cirrhotic patients, HCC patients and controls. The AA genotype and A allele could be considered risk factors for cirrhosis (OR = 1.75, 1.50) and HCC (OR = 2.19, 1.74), respectively. The AA genotype (95% CI: 0.45-6.79) and A allele (OR = 1.50, 95% CI: 0.77-2.93) may be viewed as cirrhosis risk factors based on group segregation. Additionally, the A allele, AG and AA genotypes and their combined ORs of 2.19 (95% CI: 0.58-8.23), 1.74 (95% CI: 0.90-3.37), and 1.70 (95% CI: 0.68-4.29) could all be risk factors for HCC. No genotype or allele could be regarded as a risk factor for progression of cirrhosis to HCC, according to OR values. Conclusions: The results showed no correlation between BMP-7 rs230205 [A/G] SNP and progression of cirrhosis to HCC. To confirm our findings, additional prospective large-scale research is required.

Association between IL-18 and IL-6 gene polymorphisms and the risk of T1D in Egyptian children.

PURPOSE: To test the involvement between IL-18 and IL-6 genetic polymorphisms and susceptibility to Type 1 diabetes (T1D). METHODS: Single nucleotide polymorphisms (SNPs) at positions -607A/C and - 137G/C in IL-18 promoter region were examined by sequence specific primers-polymerase chain reaction (SSP-PCR) and position -174G/C in promoter region of IL-6 gene which analyzed by Mutagenically Separated PCR (MS-PCR) in 104 T1D participants and 114 controls. RESULTS: IL-18 -137GC and -137CC genotypes and -137C allele were significantly decreased in T1D subjects (P < 0.05), while -137GG genotype was insignificantly increased as compared to controls. A significant decrease was detected in haplotype -137C/-607C frequency in T1D participants compared with controls (OR = 0.04, P < 0.001). There was significant association between IL-18 -607 of (CC, AC and AA genotypes) in age at diagnosis, glycated hemoglobin (HbA1c) and higher body mass index (BMI) (P < 0.05). CONCLUSION: This study demonstrated that IL-18 gene promoter polymorphisms might be associated with susceptibility to T1D in Egyptian children. Individuals carrying CC genotype at position -137 of IL-18 promoter may be at a low risk of T1D progression. Additionally, the susceptible combination of IL-18 and IL-6 cytokine genes associated with T1D highlight their risk toward the disease. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40200-021-00763-w.

Biomedical research in the Middle Eastern countries: update and insight using SCImago Journal Rank indicator.

BACKGROUND: There is a dire need in the Arab world and Middle Eastern countries to reform the higher education, research policy and planning for improving the quality to meet the needs of modern society. The impact factor (IF) was developed in the 1960s by Eugene Garfield of the Institute for Scientific Information (ISI) in the USA. It has been extensively used for more than 40 years. The SCImago Journal Rank (SJR) indicator belongs to this new family of indicators based on eigenvector centrality was introduced since 2007. The SJR indicator is a size-independent metric aimed at measuring the current 'average prest (se text) per paper' of journals for use in research evaluation processes. METHODS: We present the status o the biomedical scientific research in the Middle Eastern countries through the newly developed SJR indicator showing some of the proposed ways that clearly can be applied for enhancing and development of that field in the Middle Eastern countries. RESULTS: During the period from 1996 to 2008, Northern America, Western Europe and Asiatic region are the major contributors of the scientific research Worldwide. In the Middle East, the prominent two main Arab countries are Egypt and Saudi Arabia, nevertheless, they need more planned strategies for optimal contribution to their Middle East, Arab region and the World, despite the tangible achievements of the Arab states in the higher education and scientific research during the last decade. CONCLUSION: The SJR is seemingly satisfactory for ranking the countries for their scientific contribution and impact.

Modification of AOAC method 973.31 for determination of nitrite in cured meats.

A modification of AOAC Method 973.31 is proposed to improve the extraction efficiency of nitrite from cured meat samples and its subsequent quantification based on the diazotization-coupling reaction of sulfanilamide with N-(1-naphthyl)ethylenediamine dihydrochloride (NED). The various experimental parameters were thoroughly investigated. A 5 g meat sample was mixed with 400 mL water; the pH of the mixture was adjusted to 5.5 +/- 0.3 and allowed to stand for 2 h on a water bath at 80 degrees C, with occasional shaking for the complete extraction of nitrite. After quantitative filtration, an aliquot was mixed with chloroacetic-chloroacetate buffer, pH 1.80 +/- 0.05, sulfanilamide, and NED, and the absorbance of the resulting azodye was recorded at 540 nm against water as a reference. Following the recommended procedure, a linear calibration graph was obtained for up to 0.8 microg/mL NO2(-), with a correlation coefficient of 0.9996 and a detection limit (based on the 3 Sb-criterion) of 5.6 ng/mL NO2(-). The proposed method was conveniently applied to various cured meat samples and was validated by comparison with the original AOAC method and by recovery experiments that gave quantitative results (94-98%) with convenient reproducibility. Statistical analysis of the analytical data could not detect any systematic error and revealed the high accuracy and precision of the proposed method.

Solid-state dye-sensitized solar cells based on Zn1-x Sn x O nanocomposite photoanodes.

Solid-state dye-sensitized solar cells (ss-DSSCs) comprising Sn2+-substituted ZnO nanopowder were purposefully tailored via a co-precipitation method. The solar cells assembled in this work were sensitized with N719 ruthenium dye and insinuated with spiro-OMeTAD as a solid hole transport layer (HTL). Evidently, significant enhancement in cell efficiency was accomplished with Sn2+ ions-substituted ZnO photoelectrodes by maintaining the weight ratio of SnO at 5%. The overall power conversion efficiency was improved from 3.0% for the cell with pure ZnO to 4.3% for the cell with 5% SnO substitution. The improvement in the cell efficiency with Sn2+-substituted ZnO photoelectrodes is attributed to the considerably large surface area of the nanopowders for dye adsorption, efficient charge separation and the suppression of charge recombination provided by SnO. Furthermore, the energy distinction between the conduction band edges of SnO and ZnO implied a type II band alignment. Moreover, the durability as well as the stability of 15 assembled cells were studied to show the outstanding long-term stability of the devices made of Sn2+ ion substituted ZnO, and the PCE of each cell remained stable and ∼96% of its primary value was retained for up to 100 h. Subsequently, the efficacy was drastically reduced to ∼35% after 250 h of storage.

Selective Separation and Preconcentration of Caffeine from Natural and Pharmaceutical Products using New Polyurethane Foams

Abstract Two polyurethane foam-based sorbents (PUF) were synthesized by imprinting and grafting techniques and examined for selective separation and preconcentration of caffeine (CAF) in some pharmaceutical products and in black tea. Molecularly imprinted PUF was synthesized based on hydrogen-bonding interactions between CAF and alizarin yellow G (AYG) and subsequent polymerization into PUF. The static experiments indicated optimum sorption conditions at pH=6.5 and 5.5 for imprinted PUF (AY-IPUF) and grafted PUF (AY-GPUF), respectively. In the online experiments, the suitable preconcentration time was found to be 40 and 20s for (AY-IPUF) and (AY-GPUF), respectively, at a flow rate of 1.75 mL.min-1. Desorption of CAF has been affected by passing 500 µL of 0.05, 0.01 mol.L−1 HCl eluent onto (AY-IPUF) and (AY-GPUF), respectively. The online methods have provided satisfactory enrichment factors of 8.4 and 10.5 for (AY-IPUF) and (AY-GPUF), respectively. The time consumed for preconcentartion, elution and determination steps was 1.48 and 1.05 min, thus, the throughput was 42 and 57 h-1, for (AY-IPUF) and (AY-GPUF), respectively. The developed sorbents were studied for the determination of CAF in pharmaceutical samples which will be helpful to minimize caffeinism. Finally, in silico bioactivity, ADMET and drug-likeness predictive computational studies of caffeine were also carried out

Serum laminin assayed by Slot-Blot-ELISA in patients with combined viral hepatitis C and schistosomiasis.

OBJECTIVES: Hepatic schistosomiasis and chronic hepatitis C virus (HCV) are the most prevalent agents causing hepatic fibrosis in humans. Laminin (LA) has been related to liver fibrosis and subsequent development of portal hypertension in chronic liver disease. There are no available data describing the pattern of laminin in combined HCV and schistosoma-infected patients, thus the rationale of this study was to assess the serum LA as an index of liver fibrosis in patients with schistosomiasis and/or chronic viral hepatitis C and to evaluate a developed Slot-Blot Enzyme-Linked Immunosorbant Assay (Slot-Blot-ELISA) as a method of estimation. DESIGNS AND METHODS: This study included four groups: group I included 34 patients with schistosomiasis, group II included 58 patients infected with HCV, group III included 68 patients with combined chronic viral hepatitis C and schistosomiasis and group IV included 50 healthy individuals who served as a control group. Serum LA was measured in the different groups quantitatively by ELISA and semi-quantitatively by Slot-Blot-ELISA. RESULTS: Significantly higher serum LA concentrations measured by ELISA were found in patients with combined chronic viral hepatitis C and schistosomiasis than in patients with either chronic HCV (P = 0.005) or schistosomiasis (P < 0.001) alone. Serum LA was significantly higher in the patient groups than the control group (P < 0.001). Serum LA concentration was positively correlated with fibrosis grading scores. Semi-quantitative results of serum LA using the developed SB-ELISA were found to have approximately the same power of ELISA results in different groups. The overall sensitivity, specificity, positive predictive value, negative predictive value and efficiency of ELISA for estimation of serum LA were 85.6%, 84.0%, 94.5%, 64.6% and 90%, respectively and for SB-ELISA were 87.5%, 82.0%, 94%, 67.2% and 88%, respectively. CONCLUSIONS: Serum LA was significantly increased in patients coinfected with HCV and Schistosoma mansoni. The newly developed Slot-Blot-ELISA is a simple, rapid and highly sensitive assay for detection of LA in hepatic fibrosis. Moreover, all steps were performed at room temperature without the need to use expensive equipment, and this may enhance the application of this assay in screening programs. Further study is warranted for confirmation of SB-ELISA reproducibility in a large population.

Implications of CEA and p53 overexpression in the poor prognosis of colorectal cancer.

Colorectal cancer (CRC) is one of the most frequent and aggressive types of cancer. Several clinicopathologic features have been studied to identify the prognostic factors that can provide information concerning the favorable or the poor outcome of colorectal cancer. In the present study, the relationship between serum CEA, p53 expression, and DNA index to the different clinicopathological characteristics of colorectal cancer patients was sought. Fifty patients with CRC were included in this study. p53 protein was detected immunohistochemically using specific monoclonal antibodies. Samples were investigated for DNA index using flow cytometry. In addition, the serum CEA was determined using ELISA. The results showed that 27/50 (54%) were positive for p53. Concerning CEA reactivity, it was found that 35/50 (70%) were reactive for CEA. These results indicate that CEA is more sensitive than p53 to detect colorectal cancer. There was a statistically significant difference between the recurrent and nonrecurrent groups in the CRC Duke's stages, survival time, serum CEA (p = 0.001, 0.016, < 0.001, respectively). Kaplan-Meier method and log-rank test showed that the mean survival time for cases positive for both p53 and CEA is significantly different from cases positive for CEA only, positive for p53 only, and negative for both p53 and CEA (p = 0.0002). Survival time was statistically significant with respect to sex, p53, CEA, and Duke's stages (p = 0.006, 0.024, 0.001, 0.017, respectively). Cox regression model showed that the prognosis of colorectal cancer is influenced by sex, p53, CEA reactivity, and CRC Duke's stages (p = 0.014, 0.006, 0.019, 0.014, respectively). In conclusion, the use of more than one tumor marker may successfully aid in the prediction of colorectal cancer prognosis.

Relationship of Helicobacter pylori to Bcl-2 family expression, DNA content, and pathological characteristics of gastric cancer.

BACKGROUND: Despite the fact that the association of Helicobacter pylori with an increased risk of gastric cancer has been well documented, the exact mechanisms of this association have not been fully elucidated. Scarce data on H. pylori infection and its relationship with the different pathological characteristics are available in Egypt. AIM OF THE STUDY: The rationale of the present study was to determine the prevalence of H. pylori in a group of gastric cancer patients and to analyze the relationship between H. pylori infection with the different pathological characteristics including the types of gastric cancer and tumor location within the stomach, in addition, to investigate the Bcl-2 and Bax expressions along with DNA flow cytometric analysis in the gastric cancer patients with and without H. pylori infection. METHODS: Samples were obtained from 66 consecutive patients with gastric cancer (46 males and 20 females). The youngest patient was 20 yr old, the oldest 76 yr with mean age of 52.8 yr. The samples were subjected for histopathological characterization, H. pylori detection, DNA flow cytometric analysis, and Bcl-2 and Bax expressions detection, in addition to apoptosis analysis. RESULTS: The obtained results showed that the H. pylori infection was found in 38/66 (57.6%) [Odds ratio=1.357 with 95% confidence interval (CI) 0.84-2.2]. There was a statistical significance for Bcl-2, Bax, and apoptosis with H. pylori status (p = 0.009, 0.008, 0.032, respectively). On the other hand, There was a statistical significance for H. pylori infection with the disease grade (p = 0.015) and lymph node metastasis (p = 0.05). No statistical significance was found between H. pylori status with the patients' age, gender, tumor site, tumor type, depth of invasion, and stromal reaction. CONCLUSIONS: These data may indicate that the H. pylori infection not only contributes in the disease formation through the apoptosis dysregulation but also takes a part in the disease dissemination and progression. In addition, it may reflect a biologic, pathogenic, and ethnic background affecting the relationship of H. pylori infection to gastric cancer in the Egyptian patients. A high rate of smoking in Egypt and the diet are important factors that may affect such background. Further studies are warranted.

Elimination of the interferences of anions in the kinetic spectrophotometric determination of vanadium (V) solution.

Accurate determination of vanadium (V) in industrial waste water is of great importance in environmental, biological and toxicological studies. Most of kinetic spectrophotometric methods based on the catalytic effect of vanadium (V), when applied to real samples for determination of trace levels of vanadium (V) lack the satisfactory sensitivity and selectivity. This may be attributed to the serious interferences of various anions which are common pollutants in industrial waste water. The oxidation of gallic acid by ammonium persulphate, catalysed by vanadium (V) was chosen for our study. The effect of the serious interferences of various anions such as chloride, bromate, bromide, chromate, iodide, iodate, molybdate, carbonate and sulphate on the net absorbance given by 4 microg l(-1) of vanadium (V) solution were studied. The minimum concentrations of citric acid, EDTA, ascorbic acid and oxalic acid as leveling off agents required to level off interfering effects due to the aforementioned anions in the kinetic determination of vanadium (V) were 50, 70, 80 and 120 microg ml(-1), respectively. In the presence of optimum concentrations of effective leveling off agents, the dynamic range can be extended and sensitivity increased as compared with the proposed method without levelling off agents. The proposed method is a rapid, sensitive and selective method for the determination of ultra trace amounts of vanadium (V) in real samples with satisfactory results.

Synthesis, characterization of carbon polyurethane powder and its application for separation and spectrophotometric determination of platinum in pharmaceutical and ore samples.

A new chelating sorbent was synthesized by covalently linking carbon nano-fiber with ion exchange polyurethane foam (CNF-PUFIX). CNF-PUFIX was characterized using different tools e.g. elemental analysis, IR spectrum and SEM. The functional groups of PUF have disappeared. The phenolic, carboxylic, quaternary ammonium salt and tertiary amine groups are detected in the CNF-PUFIX. The sorption properties of platinum (IV) onto CNF-PUFIX were investigated, the maximum sorption of platinum ions (~100%) was at the pH ranges 4-5, shaking for 18 min and sample flow rate 1.3 mL min(-1). The experimental data was fitted by kinetic models, the pseudo-second order is predominant (R(2)=0.998), the values of h and k2 are 4.4 mmol g(-1)min(-1) and 0.15 g mmol(-1)min(-1), respectively. The sorption capacity of CNF-PUFIX and the recovery percentage of Pt (IV) were 0.19 mmol g(-1) and 99-103%, respectively (RSD=1.72%, n=5). The CNF-PUFIX could be used many times without decreasing their capacities significantly. The equilibrium process is well described by the Langmuir isotherm model (R(2)=0.857), which is attributed to the homogeneous surface structure of the CNF-PUFIX. The values of ΔG and ΔH were -3.5 and -26.1 kJ mol(-1), respectively, which indicate that the sorption of platinum onto CNF-PUFIX is spontaneous and exothermic. The lower detection limit of platinum using spectrophotometric method is 2.4 µg L(-1) (RSD~3.8%, n=6). The accuracy of the procedure was verified by the analysis of standard reference materials of pharmaceutical and granite samples.

Potential chemoprevention of diethylnitrosamine-induced hepatocarcinogenesis in rats: myrrh (Commiphora molmol) vs. turmeric (Curcuma longa).

The aim of the present study was to assess the potential chemopreventive effects of myrrh (Commiphora molmol) vs. turmeric (Curcuma longa) in hepatocarcinogenic rats induced by a single intraperitoneal injection of diethylnitrosamine (DENA) (200 mg/kg body weight). Ninety male Wistar rats used in this study were randomly divided into six equal groups (n=15). Group 1 rats served as negative controls; group 2 received a single i.p. injection of DENA and served as positive controls. Rats in both groups were fed on basal diet. Group 3 rats were fed a diet containing 5% turmeric, whereas group 4 rats were fed a diet containing 2% myrrh. Rats in groups 5 and 6 received a single i.p. injection of DENA and were fed diets containing 5% turmeric and 2% myrrh, respectively. The study demonstrated that DENA caused a significant increase in serum indices of liver enzymes and also severe histological and immunohistochemical changes in hepatic tissues. These included disorganized hepatic parenchyma, appearance of pseudoacinar and trabecular arrays of hepatocytes and alterations in CD10-immunoreactivity. Dietary supplementation of turmeric relatively improved the biochemical parameters to values approximating those of the negative controls and delayed the initiation of carcinogenesis. In contrast, myrrh did not improve the biochemical parameters or delay the hepatocarcinogenesis. Both turmeric and myrrh induced significant biochemical and histological changes in non-treated rats. In conclusion, DENA significantly changes the biological enzymatic activities in serum and the integrity of hepatic tissues. Phytochemicals with potential hepatoprotective effects must be applied cautiously owing to their potential hepatotoxicity.

Sorption characteristics of caffeine onto untreated polyurethane foam: application to its determination in human plasma.

In the present paper, the sorption properties of caffeine (CAF) onto polyether type polyurethane foam (PUF) as solid phase sorbent were investigated with UV determination at 274.3 nm. Batch and column methods were used to optimize chemical, flow, kinetic and isothermal conditions for preconcentration of CAF. Results indicated quantitative sorption of CAF at pH 8 and 30 min shaking time. The maximum sorption capacity was found to be 4.1 mg g(-1). Column preconcentration was recommended at a flow rate of 1.5 mL min(-1) and desorption with 4 mL from 0.15 mol L(-1) hydrochloric acid. The procedure provided a linear analytical range of 0.05-30 mg L(-1). The detection and quantification limits are 0.016 and 0.047 mg L(-1), respectively. The procedure was applied to determination of CAF in spiked human plasma. The obtained recoveries were 98-101% and RSD values were from 0.05 to 9.5%.

Impact of trace element changes on dehydroepiandrosterone sulfate in healthy and diabetic states among middle-age and elderly Egyptians.

The aim of this study was to confirm if there is a link between the alteration in blood levels of trace elements (chromium, copper, lead, cadmium, and zinc) and dehydroepiandrosterone sulfate (DHEAS) in healthy and diabetic states. This study is the first study to test these parameters in Egyptians. The study included 150 subjects divided into the following four groups: healthy middle-aged, healthy elderly, middle-aged diabetics, and elderly diabetics. Our results revealed a statistically significant decrease in the level of DHEAS in the elderly compared to middle-aged healthy and diabetic groups (p < 0.05). There was a significant difference between the middle-aged groups with respect to zinc, copper, chromium, and cadmium levels. Zinc and copper were lower in the diabetic subjects while chromium and cadmium were higher in the same group in comparison to healthy subjects. In the elderly groups, there were significant increases in chromium and cadmium levels in diabetic subjects rather than healthy ones. There was a significant increase in the thiobarbituric acid reactive substance level in the elderly healthy and diabetic groups and a significant decrease in the glutathione level in the elderly groups. There was no correlation between the levels of trace elements and DHEAS or between the levels of DHEAS, oxidants, and antioxidants in all of the tested groups. In conclusion, only the DHEAS level was correlated with age. There was no difference between the diabetic and healthy groups with respect to the levels of trace elements, with the exception of chromium and cadmium, which suggests the effect of pollution on the pathogenesis of diabetes in Egyptians. No correlation existed between the levels of DHEAS and trace elements, oxidants, and antioxidants. Finally, we believe that there is a large regional variation in the levels of trace elements due to different environmental exposure and nutritional factors which are responsible for contradictory results regarding the pathogenesis of diseases related to alterations in the levels of trace elements.

Redetermination of the X-ray structure of nitroxylcobalamin: base-on nitroxylcobalamin exhibits a remarkably long Co-N(dimethylbenzimidazole) bond distance.

The X-ray structures of three new crystals of nitroxylcobalamin (NOCbl) have been determined. Unlike our earlier reported structure in which NOCbl was partially oxidized (L. Hannibal, C. A. Smith, D. W. Jacobsen and N. E. Brasch, Angew. Chem., Int. Ed. 2007, 46, 5140), the O atom of the nitroxyl ligand is located in a single position with a N=O bond distance of 1.12-1.14 Å, consistent with a double bond. The Co-N-O angle is in the 118.9-120.3 Å range. The α-axial Co-N(dimethylbenzimidazole) (Co-NB3) bond distance is a remarkable 2.32-2.35 Å in length, ~0.1 Å longer than that reported for all other cobalamin structures. The change in the Gibbs free energy for the base-on/base-off equilibrium now correlates extremely well with the Co-NB3 bond distance, as observed for other cobalamins.