Investigation of mechanism and critical parameters for removal of arsenic from water using Zr-TiO2 composite

Using the microwave-hydrothermal method for the synthesis of composite, high surface density of hydroxyl groups, as an active adsorption sites for arsenic, was obtained. Adsorption mechanisms of As(III) and As(V) onto zirconium-doped titanium dioxide (Zr-TiO₂) were investigated and proposed using macroscopic and microscopic methods. Obtained results are suggesting inner-sphere and outer-sphere adsorption mechanisms for As(III) and As(V), respectively. This allowed us to identify parameters that are critical for the successful removal of arsenic from water, which is essential information for further optimization of the removal process. The composite was further applied for the removal of As(III) and As(V) from water in a dynamic flow through the reactor. Column study proved that the removal of both arsenic species below the value recommended by WHO can be achieved. Elution of As(III) and As(V) from the composite can be done by using small amounts of 0.01 M NaOH solution resulting in preconcentration of arsenic species and possible multiple usage of composite.

Synthesis, dopamine D2 receptor binding studies and docking analysis of 5-[3-(4-arylpiperazin-1-yl)propyl]-1H-benzimidazole, 5-[2-(4-arylpiperazin-1-yl)ethoxy]-1H-benzimidazole and their analogs

5-[3-(4-Arylpiperazin-1-yl)propyl]-1H-benzimidazoles and 5-[2-(4-arylpiperazin-1-yl)ethoxy]-1H-benzimidazoles were synthesized and their affinity for the D1, D2 and 5-HT1A receptors examined. They expressed a rather high affinity for the D2 dopamine receptor. The main features of ligand-D2 receptor interactions revealed by docking analyses were: salt bridge between piperazine ring protonated N1 and Asp 86, hydrogen bonds of ligand bezimidazole part with Ser 141, Ser 122 and His 189, edge-to-face interactions of arylpiperazine aromatic ring with Phe 178, Tyr 216 and Trp 182 and hydrogen bond between ethereal oxygen in ethylenoxy ligands and hydrogen of Phe 185 or Trp 115. The most active 5-[2-[4-(2-methoxyphenyl)-piperazin-1-yl]ethoxy]-1,3-dihydro-2H-benzimidazole-2-thione (27) has a maximal number of attractive interactions. A satisfactory correlation between docking of the compounds into the D2 receptor and competition binding results was observed.

Electrostatic Surface Potential Calculation on Several New Halogenated Benzimidazole-like Dopaminergic Ligands

We examined the effects of the electron density distribution (electrostatic surface potential; ESP) of several new benzimidazole-type ligands on their binding affinity for the D(1) and D(2) dopamine receptors (DAR). Receptors were prepared from synaptosomal membranes of bovine caudate nuclei. [(3)H]SCH 23390 and [(3)H]spiperone were used as specific radiolabels for the D(1) and D(2) receptors, respectively. The ESP of these compounds was calculated using Gaussian 98 W software. Calculations performed with known dopaminergic ligands showed that the electron density charge in the aromatic ring of these compounds favors a higher binding affinity for the D(2) DAR. This was confirmed by the synthesis of halogenated analogues of several known dopaminergic ligands. Halogenation resulted in an increase in the positive charge of the aromatic part of the molecule. None of the newly synthesized compounds was efficient in displacing [(3)H]SCH 23390 from the D1 DAR. The introduction of chlorine into the molecule led to a higher binding affinity for the D(2) DAR of the new ligands in comparison to both parent compounds and brominated ligands. This difference probably originates from the difference in the sizes of chlorine and bromine atoms, which could influence the interaction of a ligand with the receptor binding site. However, among the new ligands with bromine as a substituent, two compounds (8b and 10b) expressed a higher binding affinity and two of them (9b and 11b) a lower binding affinity for the D(2) DAR, when compared to unsubstituted parent compounds. These results indicate that the electrostatic surface potential of a ligand is an important factor in its interaction with the D(2) DAR and that this should be taken into account during design and synthesis of dopaminergic compounds.

D2 dopaminergic and 5-HT1A serotonergic activity of 2-(1-naphthyl)ethyl- and 2-(2-naphthyl)ethyl amines

Several tertiary 2-phenylethyl, 2-(1-naphthyl)ethyl and 2-(2-naphthyl)ethyl amines were synthesized and their binding affinities for dopamine D(1), D(2) and serotonin 5-HT(1A) receptors evaluated in radioligand binding assays. All compounds were inactive in D(1) dopamine radioligand binding assay. The 2-(1-naphthyl)ethyl analogues expressed a low but significant binding affinity for the D(2) and moderate one for the 5-HT(1A) receptor subtypes. Most of the remaining compounds expressed binding affinity at the 5-HT(1A) receptor subtype but were inactive in D(2) receptor binding assay. Based on these results and considering the chemical characteristics of the compounds synthesized and evaluated for dopaminergic and serotonergic activity throughout the present study it can be concluded that hydrophobic type of interaction (stacking or edge-to-face) plays a significant role in the formation of receptor-ligand complexes of 2-(1-naphthyl)ethyl amines. This structural motive can be applied to design and synthesize new, more potent dopaminergic/serotonergic ligands by slight chemical modifications.

Investigation of mixed D2/5-HT1A activity of N-heteroarylmethyl-N-phenylpiperazines, N-heteroarylethyl-N-phenylpiperazines and N-heteroarylpropyl-N-phenylpiperazines

Eight novel N-heteroarylalkyl-N-phenylpiperazines have been synthesized, chemically characterized and evaluated for in vitro binding affinity at the dopamine and serotonin receptors. Synaptosomal membranes of fresh bovine caudate nuclei (D1 and D2), the membranes of COS-7 cells (D4.4) and those prepared from fresh bovine hippocampi (5-HT1A) were used as a source of the corresponding receptor subtypes. [3H]SCH 23390 (D1-selective), [3H]spiperone (D2- and D4.4-selective) and [3H]-8-OH-DPAT (5-HT1A-selective) served as radioligands. None of the compounds expressed the affinity for the binding at the D1 subtype receptor. Compounds 7-9 containing a single methylene group serving as a bridge between heteroaryl- and N-phenylpiperazine part of the molecule were inactive [3H]spiperone and [3H]-8-OH-DPAT competitors. Ligands 15-19 (three methylene groups connecting heteroaryl- and N-phenylpiperazine part of the molecule) acted as moderate competitors of [3H]spiperone binding at the D2 receptor subtype, with the exception of 15 (a thione) which expressed a high binding affinity at the D2 receptor subtype. Compounds 15-19 behaved as moderate displacers of 8-OH-[3H]DPAT. Among all eight novel ligands only compound 15 expressed a moderate binding affinity at the D4.4 receptor subtype.

Reduction of diffusion capacity for carbon monoxide in diabetic patients

Diabetes can cause the development of pulmonary complications due to collagen and elastin changes, as well as microangiopathy. This study demonstrates the relationship between pulmonary complications and other chronic complications in diabetes. Twenty-seven patients with diabetes, aged 21 to 62 years, who had had the disease from 3 to 32 years, were included in this study. The protein excretion rate (PER) and the diffusion capacity of the lung for carbon monoxide (DLCO) were included as parameters of the severity of complications. PER was determined by the Biuret method. DLCO was measured by the single-breath method and was corrected by the measurement of alveolar volume (VA). The values of DLCO as corrected by VA (DLCO/VA) were included in the statistical evaluation of the results. The variables of age, duration of diabetes, and complication parameters were included in a multiple regression model with forward, stepwise selection to assess their value in predicting DLCO/VA. The variables were found to be significant predictors of DLCO/VA (R2 = 0.46, adjusted R2 = 0.32, p < 0.022). However, proteinuria was the only significant independent predictor of DLCO/VA. This finding indicates that both renal and pulmonary complications of diabetes share a similar microangiopathic background.

Emotional adjustment and metabolic control in newly diagnosed diabetic persons

Emotional reactions to diagnosis were examined in a random sample of newly detected diabetic patients (n = 71) and compared with the indicators of glycemic control in a one-year-follow-up period. The social and emotional factors subscale of the diabetes care profile was used to determine the subjectively experienced burden, negative feelings and positive coping abilities. The initial struggle against the disease indicated three characteristic emotional patterns. Feelings of being able to cope with the disease predominated in group 1 (n = 36), negative emotional reactions, but with the ability to cope were observed in group 2 (n = 17) and negative feelings combined with weak coping abilities in group 3 (n = 18). The long-term indicators of glycemic control were shown to be worst in group 3 and best in group 1. Subjective perception of the disease was not associated with sociodemographic variables, with the exception of perceived coping abilities which were better in more educated persons and those with more familial support.

[National organization of health care in diabetes based on the "Croatian model"]

This review article shows the development and organization of the "Croatian Model" of organization of health care for diabetic patients from Professor Vuk Vrhovac to this day, and its inclusion in the St. Vincent Declaration-a group of recommendations agreed upon in 1989 with the aim to decrease the morbidity and mortality of diabetes and its complications. The Model is organized on primary, secondary and terciary levels of health care. After the administrative changes of 1993, specialized health care for diabetic patients is delivered through County and Regional Centres for Diabetes and the Diabetes Reference Centre (the Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases), a scientific and educational institution and a WHO Collaborating Centre. Mention is made of the Croatian Diabetes Registry and statistical data on the morbidity (the prevalence of diabetes in Croatia is 2.37%) and mortality of diabetes mellitus and its complications, of organization of health care for diabetic patients, their medical treatment and care in Croatia.

Incidence of IDDM during 1988-1992 in Zagreb, Croatia

The objective of this study was to determine the incidence of insulin-dependent diabetes mellitus (IDDM) in the population of Zagreb, Croatia, during 1988-1992. A centralized diabetes registry was the primary source of data, while secondary sources were used to assess ascertainment. A total of 282 new cases of IDDM were diagnosed in the study period, the primary and secondary sources identifying annually 93-100% of the cases. The annual incidence rate ranged from 5.6 per 100,000 to 6.6 per 100,000. Early fatality in persons older than 50 years was the major cause of underascertainment. The incidence peaked in the 10-14 years age group (12.4 per 100,000), and remained stable after age 24 years. Males had a significantly higher incidence in the 5-9 and 24-44 years age groups. In the 45-54 years age group, females had a significantly higher incidence. No seasonality was observed. Despite the war conditions in Croatia, the low overall IDDM incidence rates did not change significantly during the study period.

War-induced prolonged stress and metabolic control in type 2 diabetic patients

Sound evidence that psychological stress may significantly worsen metabolic control in diabetic patients in lacking. The stressful effects of war on glycaemia control have not been assessed as yet. A randomly selected sample of displaced Type 2 diabetic persons (N = 44) was compared to a matched group of diabetic persons who had not been forced to leave their homes. The self-reported stress, depression level, fasting and post-prandial blood glucose, glycosylated haemoglobin and serum lipids were compared. The two groups were found to be significantly different in scores for self-reported stress and depression levels (P < 0.001). The proportion of subjects belonging to the category of clinically significant depression was larger in the group of displaced persons (P < 0.001), as well as the proportion of extreme scores for self-reported stress (P < 0.001). No significant differences between the groups were found for variables measuring metabolic control (P > 0.05), except for the serum triglycerides which were found to be significantly higher in the group of displaced persons (P < 0.01). This is assumed to be the result of differences in nutrition. The results do not demonstrate an association between prolonged stress and glycaemic control in Type 2 diabetic patients. The variability of data measuring stress and depression level in two extreme groups with respect to HbA1c values suggests that individual factors which determine the response to stressors need to be explored.

Effect of war-induced prolonged stress on cortisol of persons with type II diabetes mellitus

The study was designed to assess the impact of protracted, war-induced stress on cortisol levels and glycemic control in persons with Type II diabetes mellitus. A randomly selected sample of 44 displaced Type II diabetic persons was compared with a group of diabetic persons matched for sex, age, weight, duration of diabetes, and type of treatment who had not been forced to leave their homes. The self-reported stress, depression level, serum cortisol, fasting blood glucose, and glycosylated hemoglobin were compared. The two groups were found to be significantly different in scores for self-reported stress and depression level. Passive coping patterns prevailed in the displaced group. The serum cortisol levels correlated positively with self-reported stress, negatively with active coping patterns, and were significantly higher in the displaced persons group. No significant differences were found between the group on the variables measuring glycemic control. The results indicate that prolonged stress need not worsen glycemic control in Type II diabetic patients.