Analytical study of 226Ra activity concentration in market consuming foodstuffs of Ramsar, Iran.

BACKGROUND: Ramsar, a city of Iran located on the coast of the Caspian Sea, has been considered to be enormously important due to its high natural radioactivity levels. People living in High Level Natural Radiation Areas (HLNRAs) have been exposed by several sources, one of which could be foodstuff. However, many studies have been carried out to measure the environmental radioactivity in Ramsar, but no survey has been conducted in all stapled consumed foods yet. This study was dedicated to determine 226Ra activity concentration in the daily diets of Ramsar residents as a probable exposure. METHODS: Approximately 70 different market samples were collected during the four seasons based on the daily consumption patterns of residents which have the highest consumption and their availability in the seasons. All samples, after washing, drying and pretreatment, were analyzed for 226Ra radionuclide determination by α-spectrometry. RESULTS: The mean radioactivity concentration of 226Ra ranged between 7 ± 1 mBq Kg-1 wet weight in meat, and 318 ± 118 mBq Kg-1 for tea dry leaves. The 226Ra activity concentrations in collected samples varied from below the minimum detectable activity up to 530 ± 30 mBq Kg-1. To compare the results with United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) reference values, the 226Ra activity concentrations concluded from the results appear to be higher in milk, chicken and eggs and less in grain products, vegetables, fruits and fish products. These results indicate that no significant 226Ra contamination is present in market foodstuffs and provide reference values for the foodstuffs in Ramsar. CONCLUSIONS: Of the total daily dietary 226Ra exposure from market consuming foodstuffs for adults in Ramsar, the largest percentage was from wheat. The residents consuming wheat and manufacturing wheat products such as bread, pasta, porridge, crackers, biscuits, pancakes, pies, pastries, cakes, cookies, muffins, rolls, doughnuts, breakfast cereals and so on may receive an elevated dose in the diet. In conclusion, with regards to presence of 226Ra in foodstuffs it is necessary to monitor regularly the activity of 226Ra in foodstuffs including market and local foods.

[Retrospective study on the isolated strains of Salmonella in an Iranian hospital in Kermanshah]. / Etude rétrospective des souches de Salmonella isolées à l'hôpital iranien de Kermanchah.

A survey of occurrence of Salmonella in blood and bone marrow cultures was conducted in 1989-1990 and 1999-2000 (Sina hospital, Kermanshah). A total of 496 (12.3%) and 60 (2.4%) Salmonella strains were isolated (from 4020 and 2447 cultures). In 1989-1990, the isolated strains were: S. typhi 448 (98.5%), S. paratyphi A 40 (8%), S. paratyphi B 5 (1%) and S. paratyphi C 3 (0.5%). In 1999-2000, the isolated strains were S. typhi 59 (98%) and S. paratyphi B 1 (1.5%). There was a 60.9% reduction in the number of specimens over the 2 periods. The rate of Salmonella isolation fell from 12.3% (1989-1990) to 2.4% (1999-2000). There was a 10.2, 8.3 and 6.6 times increase in resistance of S. typhi strains to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole respectively.

[Retrospective study on the isolated strains of Salmonella in an Iranian hospital in Kermanshah]

A survey of occurrence of Salmonella in blood and bone marrow cultures was conducted in 1989- 1990 and 1999- 2000 [Sina hospital, Kermanshah]. A total of 496 [12.3%] and 60 [2.4%] Salmonella strains were isolated [from 4020 and 2447 cultures]. In 1989- 1990, the isolated strains were: S. typhi 448 [98.5%], S. paratyphi A 40 [8%], S. paratyphi B 5 [1%] and S. paratyphi C 3 [0.5%]. In 1999- 2000, the isolated strains were S. typhi 59 [98%] and S. paratyphi B 1 [1.5%]. There was a 60.9% reduction in the number of specimens over the 2 periods. The rate of Salmonella isolation fell from 12.3% [1989- 1990] to 2.4% [1999- 2000]. There was a 10.2, 8.3 and 6.6 times increase in resistance of S. typhi strains to ampicillin, chloramphenicol and trimethoprim- sulfamethoxazole respectively

Islet lysosomal enzyme activities and glucose-induced insulin secretion: effects of mannoheptulose, 2-deoxyglucose and clonidine.

In previous investigations we have shown a striking relationship between the activity of glycogenolytic glucose producing acid hydrolases in pancreatic islet tissue and certain insulin-releasing processes. In the present investigation we have studied the relation between islet lysosomal enzyme activities and glucose-induced insulin secretion in vitro in the presence of various insulin secretory inhibitors. It was observed that the nonmetabolizable glucose analogue, mannoheptulose (5 mmol/l) did induce a 2-fold increase in insulin release at low (1 mmol/l) glucose, and a total suppression of insulin release at high (16.7 mmol/l) glucose. These changes in the insulin-secretory pattern were accompanied by similar changes in the activity of islet acid alpha-glucosidase. The activities of neutral alpha-glucosidase (endoplasmic reticulum) or acid phosphatase and N-acetyl-beta-D-glucosaminidase (lysosomes) were not affected by mannoheptulose. 2-Deoxyglucose (5 mmol/l), another glucose analogue, did not increase insulin secretion or acid alpha-glucosidase activity at low glucose. At high glucose, however, a partial inhibition of both insulin release (approximately 50%) and acid alpha-glucosidase activity was seen. 2-Deoxyglucose slightly suppressed acid phosphatase activity but did not influence the activities of neutral alpha-glucosidase or N-acetyl-beta-D- glucosaminidase. Direct addition of glucose to islet homogenates showed a suppressive effect on alpha-glucosidase activity at pH 4.0 and 5.0. The glucose analogues displayed only marginal (-10%) inhibition of alpha-glucosidase activity at pH 5.0. No effect of the analogues was seen at pH 4.0.(ABSTRACT TRUNCATED AT 250 WORDS)

Homologous islet amyloid polypeptide: effects on plasma levels of glucagon, insulin and glucose in the mouse.

We examined the effects of a single intravenous injection of homologous islet amyloid polypeptide (IAPP) on the plasma levels of glucagon, insulin and glucose in the freely fed mouse. It was observed that IAPP suppressed basal glucagon levels concomitant with a decrease of the blood glucose concentrations. Basal plasma insulin levels were not affected. IAPP did not appreciably modulate the plasma concentration of glucose, insulin or glucagon after an intravenous glucose load. Further, IAPP inhibited the insulin secretory response to beta 2-adrenoceptor stimulation. IAPP also lowered the plasma glucagon levels following beta 2-adrenoceptor stimulation, whereas no apparent effect on plasma levels of glucose was observed. The data suggest that IAPP suppresses glucagon secretion and lowers blood glucose levels in the freely fed mouse. It might also exhibit a negative feedback inhibition on beta 2-adrenoceptor-induced insulin secretion, but has little influence on glucose-induced insulin release. Since IAPP is co-secreted with insulin, it is not inconceivable, that in the freely fed mouse, IAPP may act to amplify the blood glucose lowering effect of insulin through a direct suppression of glucagon secretion via the islet microcirculation.

Effect of the lysosomotropic drug suramin on islet lysosomal enzyme activities and the insulin-secretory response induced by various secretagogues.

The trypanocidal drug suramin is known to concentrate in lysosomes and to depress the activity of different lysosomal enzymes. We have previously shown that suramin can inhibit the activity of the islet lysosomal enzyme acid amyloglucosidase, a glycogenolytic glucose-producing hydrolase, which seems to be involved in certain insulin-secretory processes. In the present investigation we studied the pH dependency and dose-response effects of suramin on islet lysosomal enzyme activities as well as the effect of suramin treatment on the insulin-secretory response to various secretagogues in mice. It was found that two injections of suramin (0.18 mmol/kg) to normal NMRI mice at -24 and -2 h induced a moderate depression of the activities of islet acid amyloglucosidase (-22%) and acid phosphatase (-13%), whereas no effect was recorded for the activities of acid alpha-glucosidase, N-acetyl-beta-D-glucosaminidase and the non-lysosomal enzyme neutral alpha-glucosidase. Direct addition of different concentrations of suramin to islet homogenates showed that the drug was a potent inhibitor of acid amyloglucosidase and acid alpha-glucosidase at pH 4.0. At pH 5.0, suramin induced a large increase in acid alpha-glucosidase activity, whereas acid amyloglucosidase and acid phosphatase were inhibited. Suramin-injected mice showed a reduced insulin-secretory response to the sulphonylurea drug glibenclamide (-45%), whereas the insulin response to the cholinergic agonist carbachol or the phosphodiesterase inhibitor IBMX (1-isobutyl-3-methylxanthine) was unaffected. It is concluded that suramin inhibits islet acid amyloglucosidase activity in vivo and in vitro, whereas its effect on acid alpha-glucosidase is complex and pH dependent.(ABSTRACT TRUNCATED AT 250 WORDS)