Effects of Ramadan Fasting on Glycaemic Control Among Patients with Type 2 Diabetes: Systematic Review and Meta-analysis of Observational Studies.

INTRODUCTION: The prevalence of type 2 diabetes (T2D) is increasing around the world. Although Muslims with a physical illness are exempted from fasting during the month of Ramadan, a great number still choose to fast, often without medical consultations. The aim of this systematic review and meta-analysis was to investigate the impact of observing Ramadan fasting (RF) on glycaemic control in patients with T2D. METHODS: The Web of Science, Scopus, EBSCOhost, CINAHL, ScienceDirect, Cochrane Library, ProQuest Central and Europe PubMed Central (Medline) databases were searched for relevant studies published between January 2000 and December 2021. Observational studies that examined the changes in body weight (BW) and glucose parameters (glycosylated haemoglobin [HbA1c] and fasting blood glucose [FBG]), before and after RF among different age groups with T2D were included in the systemic review and meta-analysis. Effect sizes for the tested outcomes were calculated as weighted mean difference (WMD), with their confidence intervals (CI). Quality assessment was examined using the National Heart, Lung, and Blood Institute (NHLBI) tool. RESULTS: Of the 1592 identified records, 12 studies conducted in Middle Eastern and Asian countries were eligible and included in the quantitative analyses. The quality of the retrieved studies was evaluated and found to range between fair (83%) and good (17%). These 12 studies included 5554 participants of whom 54% were males and 46% were females. Our pooled analysis demonstrated that HbA1c and FBG levels significantly decreased after RF when compared to the pre-fasting levels (WMD = 0.55 mg/dl, 95% CI 0.33-0.77, P < 0.00001, Ι2 = 93% and WMD = 12.42, CI 6.46-18.38, P < 0.0001, Ι2 = 81%, respectively). However, the difference in BW in fasting patients after RF versus the pre-fasting stage was non-significant. Although, young patients with T2D were enrolled in the 12 selected studies, we did not find any studies that solely focussed on this group. CONCLUSION: The impact of RF on adult patients with T2D is associated with favorable outcomes. However, future studies should evaluate data from young adults separately. In addition, it is essential to identify the effects of the number of fasting days (level of exposure), diet, level of physical activity and sleeping pattern on optimal glycaemic control. This information could be utilized by medical professionals as a non-pharmacological therapeutic method for management of diabetes in patients who are willing to practice fasting during Ramadan and other months of the year. STUDY REGISTRATION: PROSPERO: CRD42022314752.

Impact of COVID-19 on Children and Young Adults With Type 2 Diabetes: A Narrative Review With Emphasis on the Potential of Intermittent Fasting as a Preventive Strategy.

Background: The world is still struggling to control the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The level of uncertainty regarding the virus is still significantly high. The virus behaves differently in children and young adults. Most children and adolescents are either asymptomatic or have mild symptoms. They generally have a very good prognosis. However, it is not well-known whether children and young adults with type 2 diabetes are at risk of getting a severe infection of COVID-19. Many Muslim children with type 2 diabetes have been performing dawn to dusk fasting during the month of Ramadan, before and during the COVID-19 pandemic, and the impact of this on their health has not been well investigated. Previous studies in adults have suggested that intermittent fasting may be beneficial in different ways including reversal of type 2 diabetes and prevention of COVID-19 infection. Objective: The primary aim of this narrative review is to summarise the impacts of the COVID-19 pandemic on children and young adults with type 2 diabetes, and to identify the knowledge gaps in the literature. It also explores the potential of intermittent fasting in reversing the pathogenesis of diabetes and highlighting how this approach could prevent these patients from developing chronic complications. Methods: This narrative review has been produced by examining several databases, including Google Scholar, Research Gate, PubMed, Cochrane Library, MEDLINE (EBSCO), and Web of Science. The most common search terms used were "COVID-19 AND Children", "SARS-CoV-2 AND/OR Children", "COVID-19 AND Diabetes" "COVID-19 Epidemiology", "COVID-19 AND Ramadan fasting", "COVID-19 and Intermittent fasting." All the resources used are either peer-reviewed articles/reports and/or official websites of various media, governmental and educational organisations. Results: Having reviewed the currently limited evidence, it has been found that the incidence of COVID-19 among children with type 2 diabetes seems to be not much different from children without diabetes. However, these patients are still vulnerable to any infection. Several studies have reported that prevention programmes such as intermittent fasting are effective to protect these groups of patients from developing any complications. Moreover, observing Ramadan fasting as a type of intermittent fasting could be beneficial for some children with established diabetes, prediabetes and people at risk. Conclusion: Children and young adults with type 2 diabetes are not at risk of severe COVID-19 infection as the case in adults with diabetes. More research is needed to identify the impact of COVID-19 and to investigate the efficacy and safety of intermittent fasting, including Ramadan fasting, among these age groups. Implementing these cost-effective programmes may have a great impact in minimising the incidence of diabetes. Moreover, this could be effective particularly at prediabetes stage by preventing these people from going onto develop type 2 diabetes and taking medications for the rest of their life and protecting people from complications linked to disease and infection.

Higher ambient temperature is associated with worsening of HbA1c levels in a Saudi population.

BACKGROUND: Ambient temperature is predicted to rise in Saudi Arabia, and how this will impact the health of its population has not been investigated. Saudi Arabia is one of the top ten countries with the highest prevalence of diabetes. The current study investigates the correlation between ambient temperature and HbA1c levels in a group of Saudis in Riyadh. METHODS: Age, gender, and HbA1c data for six years were obtained from patients' records. The maximum daily temperature of Riyadh city for the same period was obtained. RESULTS: A total of 168,614 patient records were obtained. There was a statistically significant positive correlation between ambient temperature and HbA1c levels, where for each 1°C increase in average weekly temperature HbA1c increased by 0.007%. Patients were at higher risk of having HbA1c ≥ 7% in high and moderate temperature than in low temperature (P < 0.001, odds ratio (OR): 1.134, and P < 0.001, odds ratio (OR): 1.034; respectively). The mean of HbA1c in females (7.27±1.96) was significantly lower than in males (7.40±1.86), and the probability of males having HbA1c ≥ 7% was about 17.4% higher than females. However, the HbA1c levels in females were significantly more affected by rising temperature compared to males (B = 0.003, P = 0.008). CONCLUSION: Overall, rise in ambient temperature is associated with worsening HbA1c, which could be harmful to the health of Saudis suffering from diabetes. Possible reasons for the increase in HbA1c could include reduced physical activity, reduced sunlight exposure, and dehydration during hot weather. More research on the relationship between climate change and public health in Saudi Arabia is needed.

The Influence of Gender and Menopausal Status on Hba1c Variation in a Big Data Study of a Saudi Population.

BACKGROUND: Glycated haemoglobin (HbA1c) is the gold standard measurement in the screening, diagnosis and monitoring of diabetes mellitus. Saudi Arabia has a high prevalence of diabetes mellitus that is expected to rise, and the HbA1c test is commonly used in the screening, diagnosis and monitoring of diabetes. OBJECTIVE: This study aims to assess the impact of age and gender on HbA1c levels, and the influence of menopausal status on HbA1c variation in a large group of Saudis. METHODS: Age, gender, and HbA1c results of 168,614 Saudi adult individuals were obtained from their medical records. Patients' records were extracted irrespective of their status regarding the presence of diabetes and the status of glycaemic control. Linear regression models were used for predicting HbA1c from age and gender, and their interaction term. HbA1c levels were compared between genders in different age groups and different HbA1c categories. RESULTS: There was a statistically significant positive correlation between age and HbA1c levels, where for each ten years increase in age, HbA1c increased by 0.35%. Although the overall mean HbA1c in women was significantly lower than in men (P < 0.001), women showed a significant increase in HbA1c with older age compared to men (B = 0.014, P < 0.001). Furthermore, the mean HbA1c levels in the age group > 50 years was significantly higher than before that age (P < 0.001). Thus, HbA1c increased by 1.118% in age > 50 years group compared to age ≤ 50 years, and this increase in HbA1c was significantly higher in women compared to men (B = 0.495, P < 0.001). CONCLUSION: HbA1c levels are lower in women before the estimated menopausal age, which should be taken into consideration when using HbA1c for screening, diagnosis, and monitoring of diabetes in Saudi adult women. The short lifespan of red blood cells, due to loss of blood through menstruation, in women before menopause age, is a possible reason for these variations.

Impact of Ramadan on Physical Activity and Sleeping Patterns in Individuals with Type 2 Diabetes: The First Study Using Fitbit Device.

INTRODUCTION: The impact of Ramadan fasting, a type of intermittent fasting, on the management of diabetes has not been well investigated. Physical activity, sleep duration, and time of sleep are susceptible to alterations during Ramadan due to the changes in the times and numbers of meals. This study compared physical activity and sleep patterns of individuals with type 2 diabetes mellitus (T2DM) during and after Ramadan using the international physical activity questionnaire (IPAQ) and a Fitbit Flex 2 accelerometer. METHODS: Saudi individuals (n = 36) with T2DM completed a self-reported questionnaire and wore a Fitbit device for seven consecutive days during and after Ramadan. Fitbit generated weekly step counts, activity intensities, sedentary time, and sleep durations and times. IPAQ was used to estimate the physical activity and sitting time of participants in each period. Sleep patterns were assessed in each period by a self-reported questionnaire. RESULTS: Both Fitbit and IPAQ indicated a high prevalence of low physical activity among the participants with non-significant variances between the during and after Ramadan periods. Also, a significant short daily total sleeping hours and daily night-time sleeping hours was seen during the Ramadan period. The duration of night-time sleep was observed to be low in each period. CONCLUSIONS: This is the first study to use a Fitbit device to monitor individuals with T2DM who chose to fast during Ramadan. The study shows a high prevalence of low physical activity among Saudi individuals with T2DM in each period, and short sleep durations in the during Ramadan period compared to after Ramadan period. A high prevalence of short night-time sleep duration and excessive daytime sleeping was observed in both periods and significantly in the during Ramadan period. A larger study is needed in the future covering before, during, and after Ramadan to evaluate the impact of lifestyle changes related to Ramadan fasting on type 2 diabetes.

Estimated dietary intake of essential elements from four selected staple foods in Najran City, Saudi Arabia.

The estimated dietary intake (EDI) of essential elements selenium (Se), zinc (Zn), manganese (Mn) and copper (Cu) has not been previously investigated for Najran city, Saudi Arabia. This type of information can be valuable for protecting public health. The aim of this study was to estimate the EDI of these elements. A food frequency questionnaire (FFQ) was completed by the study participants (n = 80) to obtain dietary intake of selected staple foods (rice, wheat, meat and chicken). The concentrations of Se, Zn, Mn and Cu in these staple foods were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The ranges of concentrations (mg/kg, wet weight) were as follows: Se (0.07-0.24), Zn (3.91-20.89), Mn (0.63-14.69) and Cu (0.69-2.41). The calculated ranges of EDIs (mg/kg bw/day) for the essential elements were as follows: Se 9.55 × 10-5-5.75 × 10-4, Zn 1.33 × 10-2-5.83 × 10-2, Mn 1.49 × 10-3-3.31 × 10-2, Cu 1.65 × 10-3-5.42 × 10-3. The highest EDI for Cu and Mn came from wheat. In the case of Se and Zn, the foods that contributed the highest EDI were chicken and meat, respectively. The lowest EDIs were found for Se in wheat, Zn in rice and both Mn and Cu in chicken. The percentages (%) of provisional maximum tolerable daily intake (PMTDI) for Se, Zn, Mn and Cu were 13%, 11%, 14% and 3.4%, respectively when contributions from all the four classes of foods were combined. The percentage of the recommended daily allowance (RDA) derived from these foods were 80%, 20%, 17% and 5.6% for Se, Zn, Mn and Cu were, respectively. This raises the possibility of Cu deficiency in the Najran population. However, a total diet study and human biomonitoring study is needed in the future to fully assess if people in Najran city are at risk of deficiency or excessive exposure to trace elements.

Effect of ramadan fasting on glycemic control and other essential variables in diabetic patients.

Background: Fasting during the holy month of Ramadan is a religious obligation for all Muslims who represent 1.8 billion of the world population (24%). This study explores the effect of Ramadan fasting on the blood glucose, glycated hemoglobin (HbA1c), lipid profile, sleeping quality, and essential lifestyle parameters and also explores the safety of fasting for a whole month among diabetic patients. Aim: The aim of the present study was to assess the impact of Ramadan fasting on the blood glucose, HbA1c, lipid profile, sleeping quality, and lifestyle parameters among patients with type 2 diabetes mellitus (T2DM) in Turkey. Subjects and Methods: A total of 1780 diabetic patients were approached, and 1246 (70%) participated in this cross-sectional study carried out during the period from May 27, 2017, to June 24, 2017. Data analysis comprised sociodemographic features, lifestyle habits, blood pressure measurements, serum lipid profiles, serum calcium, Vitamin D 25-hydroxy, uric acid, and HbA1c at before 4 weeks and after 12 weeks from Ramadan. Results: Out of 1246 patients, 593 (47.6%) were male and 653 (52.4%) were female. The mean ± standard deviation age of the patients was 50.39 ± 15.3 years. Males were significantly older than females (51.53 ± 12.56 vs. 49.26 ± 14.4; P = 0.003, respectively). Significant differences were found in Vitamin D, blood glucose, HbA1c level, creatinine, bilirubin, albumin, total cholesterol, triglycerides, high-density lipoprotein-cholesterol (female), low-density lipoprotein-cholesterol (male), uric acid, and systolic and diastolic blood pressure after and before the holy month of Ramadan (P < 0.05 for each). HbA1c (P < 0.001), physical activity (P < 0.001), hours of sleeping (P < 0.001), systolic blood pressure (BP) (mmHg) (P = 0.007), BMI (P = 0.016), diastolic BP (mmHg) (P = 0.018), family history (P = 0.021), and smoking (P = 0.045) were identified as significantly associated with Ramadan fasting as contributing factors. Conclusion: In one of the largest studies of its kind, we show that Ramadan fasting has positive effects on T2DM patients as it reduces their blood pressure, blood glucose, HbA1C, and BMI. Furthermore, there are improvements in the duration of sleep and physical activity, the role of Ramadan fasting in diabetes therapy has been confirmed.

RésuméContexte: Le jeûne pendant le mois sacré du Ramadan est une obligation religieuse pour tous les musulmans qui représentent 1,8 milliard de personnes dans le monde population (24%). Cette étude explore l'effet du jeûne du Ramadan sur la glycémie, l'hémoglobine glyquée (HbA1c), le profil lipidique, qualité de sommeil, et les paramètres essentiels de style de vie et explore également la sécurité du jeûne pour un mois entier chez les patients diabétiques. But: Le but de la présente étude était d'évaluer l'impact du jeûne du Ramadan sur la glycémie, l'HbA1c, le profil lipidique, le sommeil paramètres de qualité et de style de vie chez les patients atteints de diabète sucré de type 2 (DT2) en Turquie. Sujets et méthodes: Un total de 1780 patients diabétiques ont été approchés, et 1246 (70%) ont participé à cette étude transversale réalisée au cours de la période Du 27 mai 2017 au 24 juin 2017. L'analyse des données comprenait des caractéristiques sociodémographiques, des habitudes de vie, des mesures de la tension artérielle, les profils sériques des lipides, le calcium sérique, la vitamine D 25-hydroxy, l'acide urique et l'HbA1c avant 4 semaines et après 12 semaines de Ramadan. Résultats: Sur 1246 patients, 593 (47,6%) étaient des hommes et 653 (52,4%) étaient des femmes. L'âge moyen ± écart-type des patients était de 50,39 ± 15,3 ans. Les mâles étaient significativement plus âgés que les femelles (51,53 ± 12,56 contre 49,26 ± 14,4, P = 0,003, respectivement). Important différences ont été trouvées dans la vitamine D, la glycémie, le taux d'HbA1c, la créatinine, la bilirubine, l'albumine, le cholestérol total, les triglycérides, la densité lipoprotéine-cholestérol (femelle), lipoprotéine-cholestérol de basse densité (mâle), acide urique et tension artérielle systolique et diastolique après et avant le mois sacré du Ramadan (P <0,05 pour chacun). HbA1c (P < 0,001), activité physique (P <0,001), heures de sommeil (P <0,001), tension artérielle systolique (TA) (mmHg) (P = 0,007), IMC (P = 0,016), TA diastolique (mmHg) (P = 0,018), antécédents familiaux (P = 0,021), et le tabagisme (P = 0,045) a été identifié comme étant significativement associé au jeûne du Ramadan en tant que facteurs contributifs. Conclusion: Dans l'un des les plus grandes études de son genre, nous montrons que le jeûne du Ramadan a des effets positifs sur les patients atteints de DT2 car il réduit leur tension artérielle, le sang glucose, HbA1C et BMI. En outre, il y a des améliorations dans la durée du sommeil et de l'activité physique, le rôle du jeûne du Ramadan dans la thérapie du diabète a été confi rmée. Mots-clés: Indice de masse corporelle, diabète sucré, hémoglobine glyquée, jeûne du Ramadan, qualité de sommeil.

Extending the geographic reach of the water hyacinth plant in removal of heavy metals from a temperate Northern Hemisphere river.

Water hyacinth (Eichhornia crassipes) has been used for environmentally sustainable phytoremediation of water, though its use has been geographically restricted. For the first time we extend its geographical reach by investigating its potential for clean-up of water from a highly polluted British river (Nant-Y-Fendrod, a tributary of the River Tawe). Investigations using the plant were conducted at three levels: a bench-scale study using polluted river water and synthetic solutions; an in-situ trial using water hyacinth within the Nant-Y-Fendrod; and a bankside trial to pump and treat river water. The removal of the largest number of heavy metals (21) from water in a single study using ICP-MS is reported, including Sb, for the first time. Results are promising, with bench-scale tests demonstrating up to 63% removal of Al, 62% Zn, 47% Cd, 22% Mn and 23% As, during just seven hours exposure to the plant. When extended to three weeks exposure, removal is evident in the order Al > Cd > Zn > Mn > Ni > As > V. Furthermore, in-situ mean removal of 6%, 11% and 15% of Mn, Zn and Cd respectively is demonstrated. As the world learns to adapt to climate change, studies of the type reported here are needed to exploit the remarkable phytoremediation potential of water hyacinth.

Serum Albumin Modulates the Bioactivity of Rosmarinic Acid.

Rosmarinic acid (RA) is a phenolic compound with biological activity. The objective of the present study was to investigate whether this compound kept its biological activity in the presence of proteins. For this purpose, bovine serum albumin (BSA) was used as a model protein, and the capacity of the RA to inhibit acetylcholinesterase (AChE) and affect antioxidant activity was evaluated in the absence and presence of BSA. A mixture of phenolic compounds containing RA, obtained from a medicinal plant was added to this study. The AChE inhibitory activity of RA was reduced by ∼57% in the presence of BSA, while the antioxidant activity increased. These results lead to the investigation of the effect of RA on the BSA structure using Fourier transform infrared spectroscopy (FTIR). At 37°C and higher temperatures, RA caused a decrease in the temperature modifications on the protein structure. Furthermore, FTIR and native-gel analysis revealed that protein aggregation/precipitation, induced by temperature, was reduced in the presence of RA. The novelty of the present work resides in the study of the enzyme inhibitory activity and antioxidant capacity of polyphenols, such as RA, in the presence of a protein. The findings highlight the need to consider the presence of proteins when assessing biological activities of polyphenols in vitro and that enzyme inhibitory activity may be decreased, while the antioxidant capacity remains or even increases.

Estimated Dietary Intakes of Toxic Elements from Four Staple Foods in Najran City, Saudi Arabia.

Exposure of the inhabitants of Najran area in Saudi Arabia to the toxic elements As, Cd, Cr, and Pb through foods has not been previously investigated. Exposure to such elements is an important public health issue, so the study described here was performed with the aim of determining estimated dietary intakes (EDIs) for these metals in Najran area. The As, Cd, Cr, and Pb concentrations in four staple foods (rice, wheat, red meat, and chicken) were determined by inductively coupled plasma-mass spectrometry. A food frequency questionnaire (FFQ) was completed by 80 study participants. These data were used to estimate dietary intakes of the metals in the four staple foods. The mean As, Cd, Cr, and Pb EDIs in the four food types were 1.1 × 10-6-2.6 × 10-5, 1.42 × 10-5-2.2 × 10-4, 3.4 × 10-4-8.0 × 10-4, and 2.3 × 10-5-2.1 × 10-3 mg/kg bw day, respectively. Hazard Quotients (HQ) for all elements did not exceed one. The highest Pb concentration was found for chicken and the source of this toxic element in this food needs to be investigated in the future. The lowest As concentration was found for wheat highest in rice. The EDIs for all elements in the four food types were below the provisional tolerable weekly intakes set by the World Health Organization (WHO).

Urinary and dietary analysis of 18,470 bangladeshis reveal a correlation of rice consumption with arsenic exposure and toxicity.

BACKGROUND: We utilized data from the Health Effects of Arsenic Longitudinal Study (HEALS) in Araihazar, Bangladesh, to evaluate the association of steamed rice consumption with urinary total arsenic concentration and arsenical skin lesions in the overall study cohort (N=18,470) and in a subset with available urinary arsenic metabolite data (N=4,517). METHODS: General linear models with standardized beta coefficients were used to estimate associations between steamed rice consumption and urinary total arsenic concentration and urinary arsenic metabolites. Logistic regression models were used to estimate prevalence odds ratios (ORs) and their 95% confidence intervals (CIs) for the associations between rice intake and prevalent skin lesions at baseline. Discrete time hazard models were used to estimate discrete time (HRs) ratios and their 95% CIs for the associations between rice intake and incident skin lesions. RESULTS: Steamed rice consumption was positively associated with creatinine-adjusted urinary total arsenic (ß=0.041, 95% CI: 0.032-0.051) and urinary total arsenic with statistical adjustment for creatinine in the model (ß=0.043, 95% CI: 0.032-0.053). Additionally, we observed a significant trend in skin lesion prevalence (P-trend=0.007) and a moderate trend in skin lesion incidence (P-trend=0.07) associated with increased intake of steamed rice. CONCLUSIONS: This study suggests that rice intake may be a source of arsenic exposure beyond drinking water.

Increases in oxidized low-density lipoprotein and other inflammatory and adhesion molecules with a concomitant decrease in high-density lipoprotein in the individuals exposed to arsenic in Bangladesh.

Elevated exposure to arsenic has been suggested to be associated with atherosclerosis leading to cardiovascular disease (CVD). However, biochemical events underlying the arsenic-induced atherosclerosis have not yet been fully documented. The aim of this study was to investigate the associations of circulating molecules involved in atherosclerosis with arsenic exposure in the individuals exposed to arsenic in Bangladesh. A total of 324 study subjects, 218 from arsenic-endemic areas and 106 from nonendemic areas in Bangladesh, were recruited. Drinking water, hair, nail, and blood samples were collected from the study subjects for analysis. Total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) levels were lower in arsenic-endemic subjects than those of nonendemic subjects. Oxidized LDL (Ox-LDL), C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) levels were significantly higher in arsenic-endemic subjects than those in nonendemic subjects. All these circulating molecules showed significant correlations with arsenic exposure (water, hair, and nail arsenic concentrations), and all these relations were significant before and after adjusting for relevant covariates. Among the circulating molecules tested in this study, HDL, Ox-LDL, and CRP showed dose-response relationships with arsenic exposure. Ox-LDL/HDL ratios were increased with the increasing concentrations of arsenic in the water, hair, and nails. Furthermore, non-HDL cholesterol and TC/HDL ratios were significantly correlated with arsenic exposure before and after adjusting for relevant covariates. Thus, all the observed associations may be the major features of arsenic exposure-related atherosclerosis leading to CVD.

Probing protein-protein interaction in biomembranes using Fourier transform infrared spectroscopy.

The position, intensity and width of bands in infrared spectra that arise from vibrational modes within a protein can be used to probe protein secondary structure, amino acid side chain structure as well as protein dynamics and stability. FTIR spectroscopic studies on protein-protein interaction have been severely limited due to extensive overlap of peaks, from the interacting proteins. This problem is being addressed by combining data processing and acquisition techniques (difference spectroscopy and two-dimensional spectroscopy) with judicious modifications in the protein primary structure through molecular biological and chemical methods. These include the ability to modify amino acids (site-directed mutagenesis; chemical synthesis) and produce isotopically labelled proteins and peptides. Whilst great progress is being made towards overcoming the congestion of overlapping peaks, the slow progress in the assignment of bands continues to be a major hindrance in the use of infrared spectroscopy for obtaining highly accurate and precise information on protein structure. This review discusses some of these problems and presents examples of infrared studies on protein-protein interaction in biomembrane systems. This article is part of a Special Issue entitled: FTIR in membrane proteins and peptide studies.

Arsenic bioaccessibility in cooked rice as affected by arsenic in cooking water.

UNLABELLED: Rice can easily accumulate arsenic (As) into its grain and is known to be the highest As-containing cereal. In addition, the As burden in rice may increase during its processing (such as when cooking using As-polluted water). The health risk posed by the presence of As in cooked rice depends on its release from the matrix along the digestive system (bioaccessibility). Two types of white polished long-grain rice, namely, nonparboiled and parboiled (total As: 202 and 190 µg As kg(-1), respectively), were cooked in excess of water with different levels of As (0, 10, 47, 222, and 450 µg As L(-1)). The bioaccessibility of As from these cooked rice batches was evaluated with an in vitro dynamic digestion process. Rice cooked with water containing 0 and 10 µg As L(-1) showed lower As concentrations than the raw (uncooked) rice. However, cooking water with relatively high As content (≥ 47 µg As L(-1)) significantly increased the As concentration in the cooked rice up to 8- and 9-fold for the nonparboiled and parboiled rice, respectively. Parboiled rice, which is most widely consumed in South Asia, showed a higher percentage of As bioaccessibility (59% to 99%) than nonparboiled rice (36% to 69%) and most of the As bioaccessible in the cooked rice (80% to 99%) was released easily during the first 2 h of digestion. The estimation of the As intake through cooked rice based on the As bioaccessibility highlights that a few grams of cooked rice (less than 25 g dry weight per day) cooked with highly As contaminated water is equivalent to the amount of As from 2 L water containing the maximum permissible limit (10 µg As L(-1)). PRACTICAL APPLICATION: Studies on As bioaccessibility are needed for determining human As intake from rice for use in accurate risk assessments to establish updated legislation regarding maximum level of As in food. High As bioaccessibility from parboiled rice (consumed by the majority of the people in South Asia), and the findings of high As levels in discarded rice gruel (fed to livestock), has implications for human and animal health.

Interaction between Plectranthus barbatus herbal tea components and acetylcholinesterase: binding and activity studies.

Plectranthus barbatus water extracts, have been used as herbal teas, for the treatment of various diseases. In a previous study it was demonstrated that antioxidant and anti-acetylcholinesterase active extract constituents and their metabolites were found in the plasma of rats after P. barbatus tea intraperitoneal administration. Consequently, a decrease in brain acetylcholinesterase activity occurred. The aim of the present research is to elucidate how P. barbatus extract components interact with acetylcholinesterase. The estimated thermodynamic parameters suggest that the main intermolecular interaction is hydrophobic association, although hydrogen bonds between flavonoids and the active gorge of the acetylcholinesterase molecule seem to occur and have a great impact on acetylcholinesterase inhibition. The hydroxyl positions in flavonoids seem to be of utmost importance for enzyme inhibition, as they interact with specific amino acid residues in the active gorge. FTIR analysis showed that the plant extract components do not interfere with the secondary structure of the enzyme, but decreases the rate of hydrogen-deuterium exchange, possibly by decreasing solvent accessibility in the acetylcholinesterase active gorge. The spectroscopic data complements docking studies of acetylcholinesterase inhibition by plant phenolic compounds, clarifying the dominant interactions between enzyme and inhibitor and the most important structural features of the inhibitor molecules.

Elevated levels of plasma Big endothelin-1 and its relation to hypertension and skin lesions in individuals exposed to arsenic.

Chronic arsenic (As) exposure affects the endothelial system causing several diseases. Big endothelin-1 (Big ET-1), the biological precursor of endothelin-1 (ET-1) is a more accurate indicator of the degree of activation of the endothelial system. Effect of As exposure on the plasma Big ET-1 levels and its physiological implications have not yet been documented. We evaluated plasma Big ET-1 levels and their relation to hypertension and skin lesions in As exposed individuals in Bangladesh. A total of 304 study subjects from the As-endemic and non-endemic areas in Bangladesh were recruited for this study. As concentrations in water, hair and nails were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The plasma Big ET-1 levels were measured using a one-step sandwich enzyme immunoassay kit. Significant increase in Big ET-1 levels were observed with the increasing concentrations of As in drinking water, hair and nails. Further, before and after adjusting with different covariates, plasma Big ET-1 levels were found to be significantly associated with the water, hair and nail As concentrations of the study subjects. Big ET-1 levels were also higher in the higher exposure groups compared to the lowest (reference) group. Interestingly, we observed that Big ET-1 levels were significantly higher in the hypertensive and skin lesion groups compared to the normotensive and without skin lesion counterpart, respectively of the study subjects in As-endemic areas. Thus, this study demonstrated a novel dose-response relationship between As exposure and plasma Big ET-1 levels indicating the possible involvement of plasma Big ET-1 levels in As-induced hypertension and skin lesions.

Arsenic contents in Spanish infant rice, pureed infant foods, and rice.

UNLABELLED: It seems there is a positive correlation between rice content and arsenic level in foods. This is of extraordinary importance for infants below 1 y of age because their diet is very limited and in some cases is highly dependent on rice-based products; this is particularly true for infants with the celiac disease because they have no other option than consume gluten-free products, such as rice or corn. Arsenic contents were significantly higher (P < 0.001) in gluten-free infant rice (0.057 mg kg⁻¹) than in products with gluten, based on a mixture of cereals (0.024 mg kg⁻¹). Besides, especial precaution must be taken when preparing rice-based products at home, because arsenic content in Spanish rice was high, with levels being above 0.3 mg kg⁻¹ in some cases. PRACTICAL APPLICATION: From the data presented in this manuscript, it seems imperative that legislation on maximum residues of arsenic in food should be available as soon as possible to protect consumers worldwide. Research is needed to identify or breed rice cultivars with low accumulation of arsenic in the grain; otherwise the rice percentage in infant foods should be reduced.

Protective effect of Diyarbakir watermelon juice on carbon tetrachloride-induced toxicity in rats.

The present study was designed to evaluate the effect of Diyarbakir watermelon (Citrullus lanatus cv. Sürme) juice on lipid peroxidation states in rat liver, kidney and brain. In vivo administration of carbon tetrachloride (CCl(4)) once a week for 28 days caused a significant elevation of serum markers of liver damage, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TB) and decrease in albumin when compared to the control group. However, administration of carbon tetrachloride along with watermelon juice or ursodeoxycolic acid (UDCA) significantly reduces these changes. Increased lipid peroxide (LPO) level was observed in the liver, kidney and brain tissues after CCl(4) administration. However, watermelon juice and UDCA treatment prevented the increase in LPO. The results indicated that watermelon juice protects the liver, kidney and brain tissues from experimental CCl(4) toxicity in rats and that the protective effect of watermelon juice may be due to its antioxidant activity and inhibition of lipid peroxide formation. In conclusion, present study reveals biological evidence that supports the use of watermelon juice in the treatment of chemical-induced hepatotoxicity.

Betel quid chewing elevates human exposure to arsenic, cadmium and lead.

Several studies have reported increased skin lesions in betel quid (a mixture of Piper betel leaves, areca nut, tobacco/flavoured tobacco, lime) chewers compared to non-chewers, exposed to arsenic (As) contaminated drinking water in Bangladesh and India. The current study has determined As, cadmium (Cd) and lead (Pb) levels of betel quids and its components using inductively coupled plasma mass spectrometry (ICP-MS). The highest concentrations of As were found in slaked lime (4.56 mg kg(-1)) followed by Piper betel leaves (0.406 mg kg(-1)) and flavoured tobacco (zarda) (0.285 mg kg(-1)), with a mean concentrations of As in betel quids of 0.035 mg kg(-1) (SD 0.02 mg kg(-1)). Mean concentrations of Cd and Pb in ordinary quids were 0.028 (SD 0.07 mg kg(-1)) and 0.423 (SD 1.4 mg kg(-1)), respectively. We estimated that a daily intake of 6 betel quids could contribute 1.2, 1.9 and 8.5% of the provisional maximum tolerable daily intake (PMDTI) for As, Cd and Pb, respectively. Since betel quid chewing is most prevalent among women, our finding raises concern that women chewers - especially pregnant chewers - may be harming their health and that of their unborn babies through increased exposure to a mixture of toxic elements (As, Cd and Pb).

Betel quid chewing as a source of manganese exposure: total daily intake of manganese in a Bangladeshi population.

BACKGROUND: A relationship between betel quid chewing in Bangladeshi populations and the development of skin lesions and tremor has been previously reported, for people exposed to high levels of arsenic (As) through drinking contaminated groundwater. Exposure to manganese (Mn) is also known to induce neurotoxicity and levels of Mn in Bangladeshi groundwater are also high. The present study evaluates betel quid chewing as an overlooked source of Mn exposure in a Bangladeshi population. METHODS: Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine (1) urinary Mn levels for 15 chewers and 22 non-chewers from the ethnic Bangladeshi community in the United Kingdom, and (2) Mn levels in betel quids, its individual components and other Bangladeshi foods. RESULTS: Betel quid chewers displayed a significantly higher (P = 0.009) mean Mn concentration in urine (1.93 µg L(-1)) compared to non-chewers (0.62 µg L(-1)). High levels of Mn were detected in Piper betel leaves with an overall average of 135 mg kg(-1) (range 26 -518 mg kg(-1)). The mean concentration of Mn in betel quid was 41 mg kg(-1) (SD 27) and the daily intake of Mn in the Bangladeshi population was estimated to be 20.3 mg/day. Chewing six betel quids could contribute up to 18% of the maximum recommended daily intake of Mn. CONCLUSION: We have demonstrated that Mn in betel quids is an overlooked source of exposure to Mn in humans. Chewers display a 3.1 fold increased urinary Mn concentration compared to non-chewers. The practice of betel quid chewing contributes a high proportion of the maximum recommended daily intake of Mn, which could make chewers in Bangladesh more vulnerable to Mn neurotoxicity.