Immunological Profile and Markers of Endothelial Dysfunction in Elderly Patients with Cognitive Impairments

The process of aging is accompanied by a dynamic restructuring of the immune response, a phenomenon known as immunosenescence. Further, damage to the endothelium can be both a cause and a consequence of many diseases, especially in elderly people. The purpose of this study was to carry out immunological and biochemical profiling of elderly people with acute ischemic stroke (AIS), chronic cerebral circulation insufficiency (CCCI), prediabetes or newly diagnosed type II diabetes mellitus (DM), and subcortical ischemic vascular dementia (SIVD). Socio-demographic, lifestyle, and cognitive data were obtained. Biochemical, hematological, and immunological analyses were carried out, and extracellular vesicles (EVs) with endothelial CD markers were assessed. The greatest number of significant deviations from conditionally healthy donors (HDs) of the same age were registered in the SIVD group, a total of 20, of which 12 were specific and six were non-specific but with maximal differences (as compared to the other three groups) from the HDs group. The non-specific deviations were for the MOCA (Montreal Cognitive Impairment Scale), the MMSE (Mini Mental State Examination) and life satisfaction self-assessment scores, a decrease of albumin levels, and ADAMTS13 (a Disintegrin and Metalloproteinase with a Thrombospondin Type 1 motif, member 13) activity, and an increase of the VWF (von Willebrand factor) level. Considering the significant changes in immunological parameters (mostly Th17-like cells) and endothelial CD markers (CD144 and CD34), vascular repair was impaired to the greatest extent in the DM group. The AIS patients showed 12 significant deviations from the HD controls, including three specific to this group. These were high NEFAs (non-esterified fatty acids) and CD31 and CD147 markers of EVs. The lowest number of deviations were registered in the CCCI group, nine in total. There were significant changes from the HD controls with no specifics to this group, and just one non-specific with a maximal difference from the control parameters, which was α1-AGP (alpha 1 acid glycoprotein, orosomucoid). Besides the DM patients, impairments of vascular repair were also registered in the CCCI and AIS patients, with a complete absence of such in patients with dementia (SIVD group). On the other hand, microvascular damage seemed to be maximal in the latter group, considering the biochemical indicators VWF and ADAMTS13. In the DM patients, a maximum immune response was registered, mainly with Th17-like cells. In the CCCI group, the reaction was not as pronounced compared to other groups of patients, which may indicate the initial stages and/or compensatory nature of organic changes (remodeling). At the same time, immunological and biochemical deviations in SIVD patients indicated a persistent remodeling in microvessels, chronic inflammation, and a significant decrease in the anabolic function of the liver and other tissues. The data obtained support two interrelated assumptions. Taking into account the primary biochemical factors that trigger the pathological processes associated with vascular pathology and related diseases, the first assumption is that purine degradation in skeletal muscle may be a major factor in the production of uric acid, followed by its production by non-muscle cells, the main of which are endothelial cells. Another assumption is that therapeutic factors that increase the levels of endothelial progenitor cells may have a therapeutic effect in reducing the risk of cerebrovascular disease and related neurodegenerative diseases.

Serum Albumin in Health and Disease: From Comparative Biochemistry to Translational Medicine

Being one of the main proteins in the human body and many animal species, albumin plays a decisive role in the transport of various ions, electrically neutral molecules and in maintaining the colloid osmotic pressure of the blood [...].

Anticholinesterase and Serotoninergic Evaluation of Benzimidazole-Carboxamides as Potential Multifunctional Agents for the Treatment of Alzheimer's Disease

The etiology and pathogenesis of Alzheimer's disease are multifactorial, so one of the treatment strategies is the development of the drugs that affect several targets associated with the pathogenesis of the disease. Within this roadmap, we investigated the interaction of several substituted 1,3-dihydro-2-oxo-1H-benzimidazol-2-ones with their potential molecular targets: cholinesterases (ChE) and three types of the Gs-protein-coupled serotonin receptors (5-HTR) 5-HT6, 5-HT4 and 5-HT7 (5-HT4R, 5-HT6R and 5-HT7R, respectively). A microplate modification of the Ellman method was used for the biochemical analysis of the inhibitory ability of the drugs towards ChE. Molecular modeling methods, such as molecular docking and molecular dynamics (MD) simulation in water and the lipid bilayer, were used to study the interaction of the compounds with ChE and 5-HTR. In vitro experiments showed that the tested compounds had moderate anticholinesterase activity. With the help of molecular modeling methods, the mechanism of interaction of the tested compounds with ChE was investigated, the binding sites were described and the structural features of the drugs that determine the strength of their anticholinesterase activity were revealed. Primary in silico evaluation showed that benzimidazole-carboxamides effectively bind to 5-HT4R and 5-HT7R. The pool of the obtained data allows us to choose N-[2-(diethylamino)ethyl]-2-oxo-3-(tert-butyl)-2,3-dihydro-1H-benzimidazole-1-carboxamide hydrochloride (compound 13) as the most promising for further experimental development.

Albumin Is a Component of the Esterase Status of Human Blood Plasma

The esterase status of blood plasma can claim to be one of the universal markers of various diseases; therefore, it deserves attention when searching for markers of the severity of COVID-19 and other infectious and non-infectious pathologies. When analyzing the esterase status of blood plasma, the esterase activity of serum albumin, which is the major protein in the blood of mammals, should not be ignored. The purpose of this study is to expand understanding of the esterase status of blood plasma and to evaluate the relationship of the esterase status, which includes information on the amount and enzymatic activity of human serum albumin (HSA), with other biochemical parameters of human blood, using the example of surviving and deceased patients with confirmed COVID-19. In experiments in vitro and in silico, the activity of human plasma and pure HSA towards various substrates was studied, and the effect of various inhibitors on this activity was tested. Then, a comparative analysis of the esterase status and a number of basic biochemical parameters of the blood plasma of healthy subjects and patients with confirmed COVID-19 was performed. Statistically significant differences have been found in esterase status and biochemical indices (including albumin levels) between healthy subjects and patients with COVID-19, as well as between surviving and deceased patients. Additional evidence has been obtained for the importance of albumin as a diagnostic marker. Of particular interest is a new index, [Urea] × [MDA] × 1000/(BChEb × [ALB]), which in the group of deceased patients was 10 times higher than in the group of survivors and 26 times higher than the value in the group of apparently healthy elderly subjects.

Nephrotoxic Effects of Paraoxon in Three Rat Models of Acute Intoxication

The delayed effects of acute intoxication by organophosphates (OPs) are poorly understood, and the various experimental animal models often do not take into account species characteristics. The principal biochemical feature of rodents is the presence of carboxylesterase in blood plasma, which is a target for OPs and can greatly distort their specific effects. The present study was designed to investigate the nephrotoxic effects of paraoxon (O,O-diethyl O-(4-nitrophenyl) phosphate, POX) using three models of acute poisoning in outbred Wistar rats. In the first model (M1, POX2x group), POX was administered twice at doses 110 µg/kg and 130 µg/kg subcutaneously, with an interval of 1 h. In the second model (M2, CBPOX group), 1 h prior to POX poisoning at a dose of 130 µg/kg subcutaneously, carboxylesterase activity was pre-inhibited by administration of specific inhibitor cresylbenzodioxaphosphorin oxide (CBDP, 3.3 mg/kg intraperitoneally). In the third model (M3), POX was administered subcutaneously just once at doses of LD16 (241 µg/kg), LD50 (250 µg/kg), and LD84 (259 µg/kg). Animal observation and sampling were performed 1, 3, and 7 days after the exposure. Endogenous creatinine clearance (ECC) decreased in 24 h in the POX2x group (p = 0.011). Glucosuria was observed in rats 24 h after exposure to POX in both M1 and M2 models. After 3 days, an increase in urinary excretion of chondroitin sulfate (CS, p = 0.024) and calbindin (p = 0.006) was observed in rats of the CBPOX group. Morphometric analysis revealed a number of differences most significant for rats in the CBPOX group. Furthermore, there was an increase in the area of the renal corpuscles (p = 0.0006), an increase in the diameter of the lumen of the proximal convoluted tubules (PCT, p = 0.0006), and narrowing of the diameter of the distal tubules (p = 0.001). After 7 days, the diameter of the PCT lumen was still increased in the nephrons of the CBPOX group (p = 0.0009). In the M3 model, histopathological and ultrastructural changes in the kidneys were revealed after the exposure to POX at doses of LD50 and LD84. Over a period from 24 h to 3 days, a significant (p = 0.018) expansion of Bowman's capsule was observed in the kidneys of rats of both the LD50 and LD84 groups. In the epithelium of the proximal tubules, stretching of the basal labyrinth, pycnotic nuclei, and desquamation of microvilli on the apical surface were revealed. In the epithelium of the distal tubules, partial swelling and destruction of mitochondria and pycnotic nuclei was observed, and nuclei were displaced towards the apical surface of cells. After 7 days of the exposure to POX, an increase in the thickness of the glomerular basement membrane (GBM) was observed in the LD50 and LD84 groups (p = 0.019 and 0.026, respectively). Moreover, signs of damage to tubular epithelial cells persisted with blockage of the tubule lumen by cellular detritus and local destruction of the surface of apical cells. Comparison of results from the three models demonstrates that the nephrotoxic effects of POX, evaluated at 1 and 3 days, appear regardless of prior inhibition of carboxylesterase activity.

Esterase Activity of Serum Albumin Studied by 1H NMR Spectroscopy and Molecular Modelling

Serum albumin possesses esterase and pseudo-esterase activities towards a number of endogenous and exogenous substrates, but the mechanism of interaction of various esters and other compounds with albumin is still unclear. In the present study, proton nuclear magnetic resonance (1H NMR) has been applied to the study of true esterase activity of albumin, using the example of bovine serum albumin (BSA) and p-nitrophenyl acetate (NPA). The site of BSA esterase activity was then determined using molecular modelling methods. According to the data obtained, the accumulation of acetate in the presence of BSA in the reaction mixture is much more intense as compared with the spontaneous hydrolysis of NPA, which indicates true esterase activity of albumin towards NPA. Similar results were obtained for p-nitophenyl propionate (NPP) as substrate. The rate of acetate and propionate release confirms the assumption that there is a site of true esterase activity in the albumin molecule, which is different from the site of the pseudo-esterase activity Sudlow II. The results of molecular modelling of BSA and NPA interaction make it possible to postulate that Sudlow site I is the site of true esterase activity of albumin.

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.

Rational in silico design of aptamers for organophosphates based on the example of paraoxon

Poisoning by organophosphates (OPs) takes one of the leading places in the total number of exotoxicoses. Detoxication of OPs at the first stage of the poison entering the body could be achieved with the help of DNA- or RNA-aptamers, which are able to bind poisons in the bloodstream. The aim of the research was to develop an approach to rational in silico design of aptamers for OPs based on the example of paraoxon. From the published sequence of an aptamer binding organophosphorus pesticides, its three-dimensional model has been constructed. The most probable binding site for paraoxon was determined by molecular docking and molecular dynamics (MD) methods. Then the nucleotides of the binding site were mutated consequently and the values of free binding energy have been calculated using MD trajectories and MM-PBSA approach. On the basis of the energy values, two sequences that bind paraoxon most efficiently have been selected. The value of free binding energy of paraoxon with peripheral anionic site of acetylcholinesterase (AChE) has been calculated as well. It has been revealed that the aptamers found bind paraoxon more effectively than AChE. The peculiarities of paraoxon interaction with the aptamers nucleotides have been analyzed. The possibility of improving in silico approach for aptamer selection is discussed.

Conversion of solid waste to activated carbon to improve landfill sustainability

Heterogeneous composite wastes from landfills were evaluated as precursors for the generation of activated carbon (AC). A single-step chemical activation process was applied involving irradiation with microwave energy and impregnation with KOH. The average percentage yield of AC from active landfill precursor was higher than that from closed landfill for all depths sampled. Increase in impregnation ratio and irradiation power decreased the average percentage yield for both landfill precursors (active: 38.1 to 33.1%; closed: 42.1 to 33.3%). The optimum pH range for adsorption of methylene blue was pH 6-7, while adsorption increased with increase in temperature over the range 30 to 50°C. Carbonyl and hydroxyl groups were the major functional groups on the surface of AC. The properties of the AC are potentially suitable for the removal of cationic dyes and pollutants. AC generated from the landfill composite was comparable to that from other biomass being managed through AC generation. This is the first report to demonstrate the possible reuse of landfill composite as AC. The reuse option of landfill composite could provide a means of sustainable management of landfilled municipal waste.

Multivariate analysis of the effects of age, particle size and landfill depth on heavy metals pollution content of closed and active landfill precursors

Multivariate analysis of a heavy metal pollution survey of closed and active landfill precursors was carried out in order to compare environmental risk levels in relation to age, particle size and depth of the precursors. Landfill precursors (77) were collected and analyzed for 15 USEPA toxic heavy metals using ICP-MS. Heavy metals concentrations in closed landfill precursors were significantly higher than those in the active landfill for 11 of 15 heavy metals investigated (closed landfill order: Fe > Al > Mn > Cu > Pb > Ba > Co > Cr > Ni > Cd > As > Se > Ti). Cluster analysis and correlation studies indicated the distribution of the metals was more influenced by landfill precursor size than by depth of the sample. Principal component analysis (PCA) showed that 10 of 15 of heavy metals of both landfill precursors were from similar anthropogenic sources. Heavy metals pollution indices (I_geo > 5, EF > 40 and CF > 7) of both active and closed landfill precursors exceeded limits in the order of Zn > Cd > Pb > Cu > Ag, indicating a major potential health risk influenced by age and particle size of precursor. Zn, Cd, Cu and Pb of both landfill precursors exceeded the USEPA set standard for assessment of human health risk for each of the metals (1 × 10^-4 to 1 × 10^-3). This study highlights the need for the integration of a clean-up process for precursors from both types of landfill to reduce possible environmental pollution during a reuse process.

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.

Markers and Biomarkers of Endothelium: When Something Is Rotten in the State

Endothelium is a community of endothelial cells (ECs), which line the blood and lymphatic vessels, thus forming an interface between the tissues and the blood or lympha. This strategic position of endothelium infers its indispensable functional role in controlling vasoregulation, haemostasis, and inflammation. The state of endothelium is simultaneously the cause and effect of many diseases, and this is coupled with modifications of endothelial phenotype represented by markers and with biochemical profile of blood represented by biomarkers. In this paper, we briefly review data on the functional role of endothelium, give definitions of endothelial markers and biomarkers, touch on the methodological approaches for revealing biomarkers, present an implicit role of endothelium in some toxicological mechanistic studies, and survey the role of reactive oxygen species (ROS) in modulation of endothelial status.

Sulfated glycosaminoglycans in bladder tissue and urine of rats after acute exposure to paraoxon and cyclophosphamide

Glycosaminoglycans (GAGs) in the urine of Wistar rats, and on the surface of the epithelium and lamina propria of the bladder, were quantitatively assessed before and after acute intoxication with paraoxon or cyclophosphamide. Paraoxon was administered subcutaneously (s.c.) twice with an interval of 1h to a final dose of 275mg/kg; cyclophosphamide was administered intraperitoneally (i.p.) with a single dose of 100mg/kg or to a final dose of 240mg/kg (three times per 80mg/kg every 12h). GAGs on the surface of the epithelium and lamina propria of the urinary bladder of rats were quantitatively determined by Alcian blue dye staining. GAGs in the urine were determined spectrophotometrically with 1-9-dimethyl methylene blue. By 48-96h after intoxication with either paraoxon or cyclophosphamide, statistically significant increases in the concentration of GAGs were obtained both for the tissues of the bladder and the urine of rats. Cyclophosphamide, in contrast to paraoxon, caused the development of hemorrhagic cystitis in the animals. The synthesis of GAGs is considered to be compensatory response to the toxic xenobiotics.

Reactive oxygen species in pathogenesis of atherosclerosis

The volume of publications on the role of reactive oxygen species (ROS) in biological processes has been increasing exponentially over the last decades. ROS in large amounts clearly have detrimental effects on cell physiology, whereas low concentrations of ROS are permanently produced in cells and play a role as signaling molecules. An imbalance in ROS production and defense mechanisms can lead to pathological vascular remodeling, atherosclerosis being among them. The aim of this review is to examine different sources of ROS from the point of view of their participation in pathogenesis of atherosclerosis and related cardiovascular risk. Among the possible sources of ROS discussed here are mitochondria, NADPH-oxidases, xanthine oxidase, peroxidases, NO-synthases, cytochrome P450, cyclooxygenases, lipoxygenases, and hemoglobin of red blood cells. A great challenge for future research is to establish interrelations, feedback and feed-forward regulation mechanisms of various sources of ROS in development of atherosclerosis and other vascular pathologies.

Dietary intake of cadmium from Bangladeshi foods

Human exposure to cadmium (Cd) is associated with various diseases and high levels of Cd have been detected in Bangladeshi population warranting further research to identify the source of this exposure. In this study, Cd levels in 327 and 94 samples of Bangladeshi food and non-food samples, respectively, were determined using inductively coupled plasma mass spectrometry. This is the largest number of Bangladeshi food and nonfood samples investigated for their Cd content. High Cd levels were detected in leafy vegetables (mean 31 [SD 29]μg/kg). Of these vegetables, lal shak (Amaranthus tricolor) contained the highest Cd level (303 μg/kg [wet weight]; mean 100.5 [SD 95]μg/kg). Bangladeshi rice also showed significant concentration of Cd (mean 37.2 [SD 30]μg/kg). Of particular concern is the very high level of Cd detected in some puffed rice, which we attribute to the illegal practice of using urea for whitening the puffed rice. Tobacco leaves, which are commonly consumed during betel quid chewing by Bangladeshis, contain significant levels of Cd (mean 95 [SD 87]μg/kg). The total daily intake (TDI) of Cd from foods for Bangladeshis was estimated to be 34.55 μg/d. This is rather high when compared to the TDI of Cd for other populations. Our analysis reveals that this is mainly due to the very high intake of rice and vegetables, and lower consumption of animal products (which are low in Cd), by the Bangladeshis. We also determined the provisional maximum tolerable daily intake and target hazard quotients values for Cd. Clearly a more balanced diet is necessary to reduce the Cd intake in the Bangladeshi population, especially by reducing the very high intake of rice and certain leafy vegetables. Food manufacturing and agricultural practices needs to be altered to reduce the entry of Cd into the food chain.

PRACTICAL APPLICATION

Exposure to high levels of Cd can be harmful to human health and this study provides a comprehensive analysis of Cd levels in a variety of food items from Bangladesh. The findings are of particular importance to consumers of Bangladeshi foods in both Bangladesh and in other countries. Data obtained will be valuable resources for food safety and regulatory bodies as our study suggests entry of Cd in foods through use of illegal chemicals in food manufacturing processes.

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.

Risk of human exposure to arsenic and other toxic elements from geophagy: trace element analysis of baked clay using inductively coupled plasma mass spectrometry

BACKGROUND

Geophagy or earth-eating is common amongst some Bangladeshi women, especially those who are pregnant, both in Bangladesh and in the United Kingdom. A large proportion of the population in Bangladesh is already exposed to high concentrations of arsenic (As) and other toxic elements from drinking contaminated groundwater. Additional exposure to As and other toxic elements from non-food sources has not been adequately addressed and here we present the first study to monitor As levels in baked clay (known as sikor).

METHODS

Sikor samples originating from Bangladesh were digested using a microwave digester and analysed for their As, Pb, Cd, Mn, Fe and Zn levels using ICP-MS. Detailed As speciation analysis was performed using HPLC-ICP-MS.

RESULTS

Of particular concern were the levels of As (3.8-13.1 mg kg(-1)), Cd (0.09-0.4 mg kg(-1)) and Pb (21-26.7 mg kg(-1)) present in the sikor samples and their possible impact on human health. Speciation analysis revealed that sikor samples contained mainly inorganic As. Modest consumption of 50 g of sikor is equivalent to ingesting 370 μg of As and 1235 μg of Pb per day, based on median concentration values. This level of sikor consumption exceeds the permitted maximum tolerable daily intake (PMTDI) of inorganic As by almost 2-fold.

CONCLUSION

We conclude that sikor can be a significant source of As, Cd and Pb exposure for the Bangladeshi population consuming large quantities of this material. Of particular concern in this regard is geophagy practiced by pregnant women concurrently exposed to As contaminated drinking water. Future studies needs to evaluate the bioavailability of As and other elements from sikor and their impact on human health.

Analysis of organometal(loid) compounds in environmental and biological samples

Measurement of the different physicochemical forms of metals and metalloids is a necessary pre-requisite for the detailed understanding of an element's interaction with environmental and biological systems. Such chemical speciation data is important in a range of areas, including toxicology, ecotoxicology, biogeochemistry, food safety and nutrition. This chapter considers developments in the speciation analysis of organometallic compounds (OMCs), focusing on those of As, Hg, Se and Sn. Typically, organometallic analysis requires a chromatographic separation prior to analyte detection and gas chromatography (GC), high performance liquid chromatography (HPLC) or capillary electrophoresis (CE) can serve this purpose. Following separation, detection is achieved using element specific detectors (ESDs) such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma optical emission spectroscopy (ICP-OES), atomic fluorescence spectrometry (AFS), atomic absorption spectrometry (AAS) or atmospheric pressure ionization mass spectrometry (API-MS). Techniques employing a vapor generation (VG) stage prior to detection are also discussed. Complementary structural and quantitative data may be acquired through the combination of elemental and molecular mass spectrometry. The advantages and disadvantages of the various analytical systems are discussed, together with issues related to quantification and quality management.

Mattress risk factors for the sudden infant death syndrome and dust-mite allergen (der p 1) levels

Allergen-induced anaphylaxis has been suggested as a possible etiology for sudden infant death syndrome (SIDS). Some of the measures recommended for reducing the risk of allergen exposure also are recommended for reducing the risk of SIDS. The purpose of this study is to evaluate possible associations between dust-mite allergen (der p 1) levels within cot (crib) mattresses and established cot mattress risk factors for SIDS. Dust from polyurethane foam was extracted from two regions of used cot mattresses donated by 28 households in Leicester (United Kingdom) and der p 1 allergen levels estimated using a two-site monoclonal antibody system. Infant and cot environment-related factors were determined via parental questionnaire. For the infants' head region of the mattresses, the following associations were independently significant following multivariate analysis: quantity of dust extracted, with older mattresses (p = 0.014); high allergen concentrations (der p 1 per mg dust), with high frequency of minor ailments (p < 0.001) and older infants (p = 0.044); and high total der p 1 content, with high frequency of minor ailments (p = 0.014). There were no independently significant associations between levels of der p 1 in polyurethane foam and the established cot mattress risk factors for SIDS. Although der p 1 accumulates within polyurethane foam of cot mattresses with use over time, this does not provide a valid mechanistic explanation for the established cot mattress-related risk factors for SIDS. There is an association between der p 1 levels of cot mattress polyurethane foam and frequency of minor ailments; additional research is required to establish cause and effect.

Electrophysiological study of infant and adult rats under acute intoxication with fluoroacetamide

A study was conducted of acute intoxication of infant and adult Wistar rats with fluoroacetamide (FAA), an inhibitor of oxidative metabolism. FAA was administered orally to adult rats at 1/2 LD(50) and subcutaneously to infant rats at LD(100) or 1/10 LD(50). Electrocardiogram (ECG), respiration and motor activity were registered for 7 days. Clinical analysis of ECG and the heart rate variability (HRV) was carried out to assess the state of the vegetative nervous system. In adult rats, FAA caused marked disturbances in the activity of cardiovascular and respiratory systems, including the development of a potentially lethal acute cor pulmonale. Conversely, there were no significant changes of cardiac function and respiration in infant rats; they died because of extreme emaciation accompanied by retardation of development. In adult rats, bursts of associated cardiac and respiratory tachyarrhythmia, as well as regular high amplitude spasmodic sighs having a deca-second rhythm were observed. In both infant and adult rats, FAA caused short-term enhancement of humoral (metabolic) and sympathetic activities, followed by a gradual and stable predominance of parasympathetic influence on HRV. Under conditions of FAA inhibition of the tricarboxylic acid cycle, the observed physiological reactions may be explained by activation of alternative metabolic pathways. This is also supported by a lack of ontogenetically caused inhibition of spontaneous motor activity in infant rats poisoned with FAA, which highlights the significance of the alternative metabolic pathways for implementation of deca-second and minute rhythms and a lack of a rigid dependence of these rhythms upon activity of neuronal networks.

Detection of toxigenic bacteria in polyurethane foam from cot mattresses by polymerase chain reaction

A sensitive methodology for PCR detection of Staphylococcus aureus or Bordetella pertussis DNA within cot mattress polyurethane foam was developed. The assay's applicability was evaluated on polyurethane foam from used cot mattresses. S. aureus DNA was detected in 42% of mattresses of sudden infant death syndrome (SIDS) victims and 29% of comparison group (no death) mattresses tested. B. pertussis DNA was detected in 50% of SIDS mattresses and 27% of comparison group mattresses. There was no significant statistical association between SIDS cases and the presence of S. aureus or B. pertussis DNA in cot mattress polyurethane.

[Studies of interaction of intracellular signalling and metabolic pathways under inhibition of mitochondrial aconitase with fluoroacetate]

Mitochondrial aconitase has been shown to be inactivated by a spectrum of substances or critical states. Fluoroacetate (FA) is the most known toxic agent inhibiting aconitase. The biochemistry of toxic action of FA is rather well understood, though no effective therapy has been proposed for the past six decades. In order to reveal novel approaches for possible antidotes to be developed, experiments were performed with rat liver mitochondria, Ehrlich ascite tumor cells and cardiomyocytes, exposed to FA or fluorocitrate in vitro. The effect of FA developed at much higher concentrations in comparison with fluorocitrate and was dependent upon respiratory substrates in experiments with mitochondria: with pyruvate, FA induced a slow oxidation and/or leak of pyridine nucleotides and inhibition of respiration. Oxidation of pyridine nucleotides was prevented by incubation of mitochondria with cyclosporin A. Studies of the pyridine nucleotides level and calcium response generated in Ehrlich ascite tumor cells under activation with ATP also revealed a loss of pyridine nucleotides from mitochondria resulting in a shift in the balance of mitochondrial and cytosolic NAD(P)H under exposure to FA. An increase of cytosolic [Ca2+] was observed in the cell lines exposed to FA and is explained by activation of plasma membrane calcium channels; this mechanism, could have an impact on amplitude and rate of Ca2+ waves in cardiomyocytes. Highlighting the reciprocal relationship between intracellular pyridine nucleotides and calcium balance, we discuss metabolic pathway modulation in the context of probable development of an effective therapy for FA poisoning and other inhibitors of aconitase.

Effect of fasting on the pattern of urinary arsenic excretion

Millions of people in some of the poorest regions of the world are exposed to high levels of arsenic through drinking contaminated water. It has been reported that development of cancer caused by arsenic exposure in such populations is dependent on dietary and nutritional factors which can modulate arsenic metabolism. Many people in arsenic exposed regions of Bangladesh and India practice fasting for at least one month every year when they refrain from consumption of food and fluid during daylight hours. How such practices may modulate arsenic metabolism has not been previously investigated. This study investigated this issue by determining total arsenic and its species in urine samples from a group of 29 unexposed volunteers at the beginning of the fasting and at the end of approximately 12 h of fasting period. Inductively coupled plasma mass spectrometry (ICP-MS) and high performance liquid chromatography (HPLC) coupled with ICP-MS was used to measure the total arsenic and arsenic speciation in the urine samples, respectively. The mean total levels of arsenic at the beginning of fasting (18.3 microg g(-1) creatinine) and at the end of approximately 12 h of fasting (17.7 microg g(-1) creatinine) did not differ significantly (p > 0.05). However, the percentages of urinary arsenic as the methylated arsenic species methylarsonate (MA) were found to be significantly different (p < 0.05) and this species was observed more frequently at the end of fasting, although its overall concentration was similar. There were no significant differences (p > 0.05) in both the concentrations and percentages of other urinary arsenic species detected, namely arsenobetaine (AB) and dimethylarsinate (DMA). Arsenite (As(III)) and arsenate (As(V)) were also analyzed, but were not detected. We conclude that fasting for a period of 12 h results in a significant increase in the percentage of urinary arsenic as MA, and its frequency of detection in the volunteers at the end of the fasting period is almost nine fold higher. This suggests that metabolism of arsenic is altered by fasting.

Understanding arsenic metabolism through a comparative study of arsenic levels in the urine, hair and fingernails of healthy volunteers from three unexposed ethnic groups in the United Kingdom

Very little is known about arsenic (As) metabolism in healthy populations that are not exposed to high concentrations of As in their food or water. Here we present a study with healthy volunteers from three different ethnic groups, residing in Leicester, UK, which reveals statistically significant differences in the levels of total As in urine and fingernail samples. Urine (n = 63), hair (n = 36) and fingernail (n = 36) samples from Asians, Somali Black-Africans and Whites were analysed using inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectroscopy (GF-AAS). The results clearly show that the total concentrations of As in urine and fingernail samples of a Somali Black-African population (urine 7.2 microg/g creatinine; fingernails 723.1 microg/kg) are significantly (P < 0.05) different from the Asian (urine 24.5 microg/g creatinine; fingernails 153.9 microg/kg) and White groups (urine 20.9 microg/g creatinine; fingernails 177.0 microg/kg). The chemical speciation of As in the urine of the three groups was also measured using high performance liquid chromatography coupled to ICP-MS. This showed that the proportion of the total urinary As present as dimethylarsenate (DMA) was higher for the Somali Black-African group (50%) compared to the Asians (16%) and Whites (22%). However, there was no significant difference (P > 0.05) in the level of As in the hair samples from these three groups; Somali Black-Africans (116.0 microg/kg), Asians (117.4 microg/kg) and Whites (141.2 microg/kg). Significantly different levels of total As in fingernail and urine and a higher percentage of urinary DMA in the Somali Black-Africans are suggestive of a different pattern of As metabolism in this ethnic group.

Determination of fluoroacetic acid in water and biological samples by GC-FID and GC-MS in combination with solid-phase microextraction

A novel procedure has been developed for determination of fluoroacetic acid (FAA) in water and biological samples. It involves ethylation of FAA with ethanol in the presence of sulfuric acid, solid-phase microextraction of the ethyl fluoroacetate formed, and subsequent analysis by GC-FID or by GC-MS in selected-ion-monitoring mode. The detection limits for FAA in water, blood plasma, and organ homogenates are 0.001 microg mL(-1), 0.01 microg mL(-1), and 0.01 microg g(-1), respectively. The determination error at concentrations close to the detection limit was less than 50%. For analysis of biological samples, the approach has the advantages of overcoming the matrix effect and protecting the GC and GC-MS systems from contamination. Application of the approach to determination of FAA in blood plasma and organ tissues of animals poisoned with sodium fluoroacetate reveals substantial differences between the dynamics of FAA accumulation and clearance in rabbits and rats.

Toxicology of fluoroacetate: a review, with possible directions for therapy research

Fluoroacetate (FA; CH2FCOOR) is highly toxic towards humans and other mammals through inhibition of the enzyme aconitase in the tricarboxylic acid cycle, caused by 'lethal synthesis' of an isomer of fluorocitrate (FC). FA is found in a range of plant species and their ingestion can cause the death of ruminant animals. Some fluorinated compounds -- used as anticancer agents, narcotic analgesics, pesticides or industrial chemicals -- metabolize to FA as intermediate products. The chemical characteristics of FA and the clinical signs of intoxication warrant the re-evaluation of the toxic danger of FA and renewed efforts in the search for effective therapeutic means. Antidotal therapy for FA intoxication has been aimed at preventing fluorocitrate synthesis and aconitase blockade in mitochondria, and at providing citrate outflow from this organelle. Despite a greatly improved understanding of the biochemical mechanism of FA toxicity, ethanol, if taken immediately after the poisoning, has been the most acceptable antidote for the past six decades. This review deals with the clinical signs and physiological and biochemical mechanisms of FA intoxication to provide an explanation of why, even after decades of investigation, has no effective therapy to FA intoxication been elaborated. An apparent lack of integrated toxicological studies is viewed as a limiter of progress in this regard. Two principal ways of developing effective therapies for FA intoxication are considered. Firstly, competitive inhibition of FA interaction with CoA and of FC interaction with aconitase. Secondly, channeling the alternative metabolic pathways by orienting the fate of citrate via cytosolic aconitase, and by maintaining the flux of reducing equivalents into the TCA cycle via glutamate dehydrogenase.

Growth and survival of bacteria implicated in sudden infant death syndrome on cot mattress materials

AIMS

To compare growth and survival of selected bacteria implicated in sudden infant death syndrome (SIDS) on cot mattress polyurethane (PU) inner-foams and on different types of cot mattress cover materials.

METHODS AND RESULTS

Escherichia coli, Staphylococcus aureus or Streptococcus pyogenes were inoculated onto swatches of new-unused cot mattress PU inner-foam and onto three types of cot mattress covers (polyvinyl chloride, cotton and polyester). The influence of inoculation cell density, relative humidity (RH) and temperature of incubation on survival was assessed by recovery of cells in 0.85% NaCl, with viable cell enumeration by plate counting on selective and differential media. Utilization of carbon and nitrogen sources within cot mattress PU was assessed by following growth on aqueous leachate from PU, and by colorimetric determination of aromatic amines. Good survival capability (>206 d) was shown by all three test species on PU inner-foam and on polyester mattress cover at high RH (75%), but only by Staph. aureus on PU at low RH (25%). Aqueous soluble material from PU foam supports bacterial growth; removal of aromatic amines from aqueous leachate from PU accompanies growth of Staph. aureus.

CONCLUSIONS

Staphylococcus aureus has good survival capability on cot mattress PU foam, even at low RH. Soluble material within PU can serve as carbon and nitrogen sources for bacterial growth.

SIGNIFICANCE AND IMPACT OF THE STUDY

Prolonged survival of Staph. aureus on PU at low RH could explain, in the context of the common bacterial toxins hypothesis, an increased risk of SIDS associated with used infant mattresses.

Aerial release of bacteria from cot mattress materials and the sudden infant death syndrome

AIM

To investigate aerial release of bacteria from used cot mattresses and to assess factors that may influence this process.

METHODS AND RESULTS

Movement on used mattresses, simulating that of an infant's head, significantly enhanced aerial release of naturally acquired bacteria from the polyurethane foams (total count data, P = 0.008; Staphylococcus aureus, P = 0.004) or from polyvinyl chloride covers (total count data, P = 0.001). Aerial release of naturally acquired bacteria from used cot mattresses showed high variability and was poorly correlated (R2 < or = 0.294) with bacterial cell density within the materials. In experiments involving inoculation of S. aureus and Escherichia coli onto the polyurethane of unused cot mattresses, aerial release of the species correlated well (R2 > or = 0.950) with inoculation density when simulated infant head movement was applied. Aerial release of these bacterial species from the material decreased with increase in width or aqueous content of the material, and was lower from polyurethane foam of a used cot mattress.

CONCLUSIONS

Simulated infant movement and mattress related factors influence aerial release of bacteria from cot mattress materials. With simulated infant movement on cot mattress polyurethane foam, levels of airborne bacteria above the material are proportional to bacterial population levels inoculated onto the material.

SIGNIFICANCE AND IMPACT OF THE STUDY

Cot mattresses harbouring relatively high levels of naturally acquired toxigenic bacteria, such as S. aureus, could pose a relatively high risk of infection to the infant's respiratory tract through increased aerial contamination. This has impact in the context of recent findings on cot mattress related risk factors for sudden infant death syndrome.

Cot mattresses as reservoirs of potentially harmful bacteria and the sudden infant death syndrome

Cot mattress materials were investigated as potential reservoirs of bacteria in relation to the sudden infant death syndrome (SIDS). The sleeping position of the infant significantly influenced bacterial population density of cot mattress polyurethane foams (p<0.0000001) and their covers (p<0.004). Staphylococcus aureus was isolated at significantly higher frequency (p<0.03) from the infant's head region of cot mattress materials. Significantly higher bacterial population densities (p<0.001) were associated with polyurethane foams from non-integral mattresses (exposed polyurethane foam), when compared to those from mattresses completely covered by polyvinyl chloride (integral type mattress). The frequency of isolation of S. aureus from polyurethane foams from non-integral mattresses was also significantly higher (p=0.03) than from foams from the integral type. The following factors were significantly associated with increased frequency of isolation of S. aureus: from the polyurethane foam, previous use of non-integral mattresses by another child (p=0.03 for all sample sites, p=0.01 for torso region); from the covers, sleeping in the prone position (p=0.003 head region, p=0.001 torso region). Prone sleeping was also significantly associated with increased bacterial population levels (p=0.01) and increased frequency of isolation of Escherichia coli (p=0.02) from the torso region of cot mattress covers. These findings could explain some recently identified risk factors for SIDS associated with type and previous use of cot mattresses. Clostridium perfringens was isolated at very low frequency and Streptococcus pyogenes was not isolated from any cot mattress materials tested.