Mariana D. Argirova

High-nitrate levels in drinking water may be a risk factor for thyroid dysfunction in children and pregnant women living in rural Bulgarian areas.

Nitrate inhibits the accumulation of iodide in thyroid gland. The aim of present study was to evaluate the influence of this ion on the iodine status of two risk population groups. Subjects of study were pregnant women and children aged between 3 and 6 years from two villages in Bulgaria with high- and low-nitrate levels in drinking water. The relative risk of thyroid disorders for the pregnant women living in the village with high-nitrate levels in drinking water expressed as an odds ratio was 5.294 (95% confidence intervals 1.003-27.939; P=0.0454) and was considered as significant. Statistically significant differences were found between the goiter rate in exposed and non-exposed pregnant women. The relative risk of thyroid dysfunction for the children exposed to a high-nitrate level, expressed as an odds ratio was 2.333 (95% confidence intervals 0.8491-6.412; P=0.1396) and was considered as not significant; the goiter prevalence in the exposed children was also not statistically different. The results of the study confirmed the role of high-nitrate level in drinking water as a risk factor for thyroid dysfunction in vulnerable population groups.

Iodine status and goitre prevalence in nitrate-exposed schoolchildren living in rural Bulgaria

Nitrate and perchlorate are well-known water pollutants that are harmful to human health. They may inhibit the accumulation of iodide in the thyroid gland. The present study investigated iodine status and goitre prevalence in schoolchildren aged 7-14 years from two villages in Bulgaria with high and low levels of nitrate, and negligible levels of perchlorate in drinking water. Comparison between the mean and median urinary iodine concentrations of the exposed and non-exposed children showed a statistically significant difference for the boys. A statistically significant difference was also found for goitre prevalence between the exposed and non-exposed children. The relative risk for schoolchildren exposed to a high level of nitrate in drinking water, expressed as an odds ratio, was 3.014 (95% confidence intervals 1.293-7.027; P=0.0105) and this was considered to be significant. This study confirmed that a high level of nitrate in drinking water is a risk factor for thyroid dysfunction in this population.

Iodine Status of Children Living in Areas With High Nitrate Levels in Water

Several researchers have suggested a possible relationship between nitrate intake and the development of goiter in children. The present cross-sectional study included schoolchildren between the ages of 11 and 14 years from 2 villages in Bulgaria with high and low nitrate levels in drinking water. The comparison between the median urinary iodine levels of the total number of exposed (179.0 μg/l) and nonexposed (202.50 μ/l) children showed statistically significant differences. The relative risk for the children exposed to high nitrate levels in drinking water, expressed as the odds ratio, was 8.145 (95% confidence interval = 1.67-39.67). The authors considered this to be very significant. They found a statistically significant difference for the prevalence of goiter among the exposed and nonexposed children. The results of the study confirmed the role of high nitrate levels in drinking water as a health risk factor for thyroid dysfunction.

Benefits and risks from the national strategy for improvement of iodine nutrition in Bulgaria: study on schoolchildren living in a rural area

OBJECTIVES To assess the effectiveness of iodine prophylaxis in schoolchildren, living in a rural area in South Bulgaria, after the introduction of salt iodization. STUDY DESIGN The study subjects were 114 schoolchildren (59 boys and 55 girls), aged 11-14 years, living in a rural area in Bulgaria. Urinary iodine concentration was used as an index of iodine intake. The iodine level in table salt used in the childrens households was also monitored. METHODS Iodine concentration was measured by the Sandell-Kolthoff reaction. The iodine content of samples of table salt was determined by redox titration. RESULTS The median urinary iodine concentration of the inspected schoolchildren was >200 microg/l, which indicates that iodine intake is more than adequate. An unfavourable result of the study was that 52.6% of the schoolchildren had more than adequate or excessive iodine intake. The hypothesis that this iodine overload may be due to poorly controlled salt iodization was confirmed by monitoring the iodine content in samples of table salt; three of six specimens contained iodine above the recommended level. DISCUSSION Although the results indicated that the national strategy has had a positive effect on iodine-deficiency disorders, excessive iodization during the production of table salt and excessive consumption may be potential risks for the development of thyroid-related diseases.

Evaluation of endemic goiter prevalence in Bulgarian schoolchildren: results from national strategies for prevention and control of iodine-deficiency disorders.

Iodine deficiency is a major health problem worldwide. The environment of the Balkan countries, including Bulgaria, is distinguished for its low iodine content. In 1994, the strategies for the prevention and control of iodine-deficiency disorders were actualized in Bulgaria and universal salt iodization and supplementation for the risk population groups (schoolchildren, pregnant women) were introduced. The aim of this study was to assess the effectiveness of the iodine prophylaxis in schoolchildren, living in an endemic for goiter area after the introduction of salt iodization in Bulgaria. For this purpose, the goiter prevalence and iodine status in 483 schoolchildren (274 boys and 209 girls) aged between 8 and 15 yr, living in an endemic for goiter area in Bulgaria were evaluated. Despite the normalization of iodine supply, mild iodine deficiency on the basis of goiter prevalence (16.15%) and urinary iodine excretion was found. These data indicate the need for reevaluation of the national strategy for prevention of iodine deficiency.

Region-specific pathophysiological alterations occurring in calf lenses in vitro during hyperglycemia.

Abstract.Background: The early onset of cataract during diabetes may come about via a variety of pathogenic pathways, but an uncertainty about the significance of each of them exists. Methods: Calf lenses cultured in a high glucose medium were investigated for regional variations in sorbitol accumulation, changes in lactate dehydrogenase activity, and formation of carbonyl groups in proteins. The results obtained were used to evaluate the contributions of various pathways to the alterations in the lens during hyperglycemia and to relate these findings to morphologically diverse lens substructures. Results: The highest sorbitol accumulation was found in both the anterior and posterior cortex of lenses incubated in hyperglycemic medium. Lactate dehydrogenase activity was strongly affected by high sugar concentration, but the alterations in the equatorial part of lenses were more moderate relative to other substructures. After incubation with glucose, the concentration of Amadori products did not increase significantly compared to non-incubated and incubated controls. Nuclear proteins exhibited the highest level of oxidation. Conclusion: The process of sorbitol accumulation is more evident than glycation in the initial stage of hyperglycemia. Lens cortex is affected faster by elevated glucose, while the nucleus is more susceptible to prolonged effects of oxidation, glycation, and glycoxidation.

Iodine Nutrition in Bulgaria: Results from the National Strategy for Elimination of Iodine Deficiency Disorders in Bulgaria – Epidemiologic Studies on Risk Population Groups

The environment of the Balkan countries, including Bulgaria, is known for its low content of iodine. The iodine deficiency regions comprise 1/3 of the country territory. The first national program for control of iodine deficiency disorders (IDD) was introduced in Bulgaria in 1958; however, iodine prophylaxis was interrupted during the period of market-oriented reforms. The strategies for prevention and control of IDD in Bulgaria were updated in 1994 and universal salt iodization and iodine supplementation for the population groups at risk were introduced. Despite the results achieved the level of information in the population concerning the health consequences of iodine deficiency and the purpose of applied prophylaxis with salt iodine fortification is not yet sufficient. Therefore, in the national action plan “Food and Nutrition, 2005–2010” an instruction on iodine deficiency problems for general practitioners, health education lessons in schools, and information for the whole population through appropriate informative flyers is included. The results from the studies of iodine status of schoolchildren living in urban and rural areas in south Bulgaria indicated that about 50% of them had optimal iodine nutrition. Statistically significant differences were found in some of the subgroups with different iodine status, which underlines the importance of socioeconomic status and the living standard of the population for the development of IDD. An unfavorable result found in these surveys was that a significant number of the children, schoolchildren and pregnant women had more than adequate or excessive iodine intake. In a population characterized by long-standing iodine deficiency and a rapid increase in iodine intake, there is a risk of iodine-induced hyperthyroidism.

Public health: the science of promoting health

Public health is “the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals” (Winslow 1920). The United Nations’ World Health Organization defines health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.” (WHO 1946). Public health plays an important role in disease prevention efforts in both the developing world and in developed countries through local health systems and through international non-governmental organizations. Today, most governments recognize the importance of public health programs in reducing the incidence of disease, disability, and the effects of aging, although public health generally receives significantly less government funding compared to medicine. This issue of the Journal of Public Health covers a broad range of current topics in public health; among them are the tobacco-related health problems. A number of scientific and medical evidence shows that the dangers associated with secondhand smoking are extremely serious and relevant. Many countries have implemented a full publicsmoking ban to protect the health of their citizens from the harmful effects of passive smoke. Balachandar et al. study the frequency of chromosomal aberrations among infertile male subjects in comparison to control subjects with the same pack-years and their offsprings (secondhand smokers). The authors identify higher degrees of chromosomal damage in infertile subjects compared to control smokers but Y chromosomal alterations were found in both subjects and offsprings. This finding is a distress signal for possible transmission of the current health-related problems of smokers into the next generation. Health hazards of obesity and being overweight are a growing concern for public health professionals. A study by Bau al. points out that postmenarche girls are more than twice as likely to be overweight and/or abdominally overweight as premenarche girls within the same age group. Therefore, not only the age but also the progress of maturation is important for assessing the growth and health of adolescents. For a long time obesity was considered a problem in high-income countries but now it is also growing in lowincome regions, especially in urban settings (James et al. 2001). A cohort study by Shiying Fu et al. examines the influence of central obesity indexed by waist circumference to height ratio (W/H) on the adverse levels of metabolic syndrome among adults with normal weight in a lowincome rural Chinese region. Groups adjusted for age and sex with W/H index below 0.5 have significantly different levels of blood pressure, triglycerides, high-density lipoprotein-bound cholesterol, and glucose compared to the group with W/H index above 0.5. The findings from the study underscore the importance of the utility of W/H as a measure of abdominal fat accumulation in predicting metabolic syndrome even among individuals with normal weight in terms of body mass index. During the last years, a dramatic increase in the average lifespan is widely credited to public health achievements such as vaccination programs and control P. D. Gatseva (*) Department of Hygiene, Ecology and Epidemiology, Medical University, 15a Vassil Aprilov Street, 4002 Plovdiv, Bulgaria e-mail: gatseva_p@mail.bg

Participation of cAMP in tacrine-induced gastric smooth muscle relaxation

Tacrine, a well-known acetylcholinesterase inhibitor, applied in concentrations higher than 2×10−5 mol/l promoted Ca2+-independent relaxation of rat gastric smooth muscles in experiments in vitro. The relaxation was not cholinergic and was a result of influence of tacrine over intracellular signaling pathways regulating smooth muscle contraction/relaxation. The nature of this untypical muscle relaxation was studied by using smooth muscle strips isolated from rat stomach. Their bioelectrical and mechanical responses were recorded after treatment with tacrine and different activators or blockers of intracellular pathways involved in muscle contractility. Following the activation of adenylate cyclase with 1×10−6 mol/l forskolin and increase in the concentration of cyclic adenosine monophosphate (cAMP) after application of 4×10−5 mol/l SQ22536, a significant decrease in the muscle relaxation was observed. Theophylline (2×10−4 mol/l), a phosphodiesterase inhibitor, had no effect on the amplitude of tacrine-induced relaxation. The latter was also reduced by inhibition of protein kinase A (PKA) with 5×10−6 mol/l KT5720. These findings support the assumption that tacrine promoted smooth muscle relaxation through PKA-induced phosphorylation and inhibition of myosin light chain kinase activity. The reduction of spike-linked Ca2+ influx provoked by tacrine was probably a secondary contributing process, associated with an influence of increased cAMP level on Ca2+ channels.

Biochemical Changes in Experimental Rat Model of Abdominal Compartment Syndrome

Abstract Background: Increased intra-abdominal pressure (IAP) causes tissue ischemia, subsequent hypoxia, and impairment of normal tissue metabolism. Elevation of IAP above 20 mmHg leads to progression of abdominal compartment syndrome (ACS) that is associated with organ dysfunction or failure not previously manifested. Aim: To evaluate the eff ects of diff erent grades and time of exposure to IAP on biochemical parameters and oxidative stress in organs aff ected by ischemia using previously developed rat model. Results: Three experimental groups exposed to diff erent IAP and time frames were tested for liver, kidney, and pancreas injury by measuring the activities of tissue specifi c enzymes in blood serum. Elevated activities of aspartate aminotransferase, pancreatic amylase, lipase, and higher concentrations of D-lactate, urea, and creatinine were found in some of the experimental groups compared to a control group of animals not subjected to increased IAP. Increased levels of biomarkers of oxidative stress as well as decrease in concentration of the major cellular antioxidant glutathione indicated the presence of oxidative injury as a result of elevated IAP. Conclusions: The developed rat model is appropriate to study the mechanism and manifestation of tissue injury during diff erent grades of elevated IAP but also to test approaches aimed to attenuate the detrimental eff ects of ACS. This study also underlines the necessity of using not a single but a set of biochemical parameters in order to assess the severity of tissue injury during elevated IAP and progression to ACS.