Copper and zinc in four freshwater fish species from Lake Pamvotis (Greece).

Lake ecosystems are vulnerable to heavy-metal pollution. Fish samples are considered as one of the most indicative factors, in freshwater systems, for the estimation of trace metals pollution potential. Lake Pamvotis (NW Greece) is a typical Mediterranean ecosystem of great importance in regard to biodiversity and to aesthetic value. The fish species found most commonly in the lake are Cyprinus carpio, Silurus aristotelis, Rutilus ylikiensis, and Carassius gibelio. The aim of the present study is to evaluate the level of contamination of two essential heavy metals (copper and zinc) appearing at high concentrations in lake water in the above four fish species. Metal concentrations were measured by atomic absorption spectroscopy in three different tissues (muscle, liver, gonads) in order to assess the fish contamination. A two-factor analysis of variance, based on the procedure of general linear models, was employed in which fish species (four levels) and fish tissue (three levels) were examined for potential influence on Cu and Zn concentrations. Differences between level means per factor were treated using Tukey's multiple comparisons of means. The study showed that C. carpio and R. ylikiensis presented the highest metal content. Tissues analysis revealed that liver and gonads accumulated the highest levels of Cu and Zn. Metal concentration in the edible part of the examined fish (muscle) were in the safety-permissible levels for human consumption.

Ascorbic acid (vitamin C) effects on withdrawal syndrome of heroin abusers.

BACKGROUND: Ascorbic acid (vitamin C), administered orally in high doses has been observed to relieve pain and reduce opioid use in cancer patients. In vitro studies have also shown that antioxidants, such as vitamin C, may, at high concentrations, inhibit the endogenous opioid degrading metalloenzyme and increase endorphin levels. In the present study the effects of oral administration of high doses of vitamin C on withdrawal syndrome of heroin abusers were investigated. MATERIALS AND PATIENTS: Ascorbic acid at doses of 300 mg/kg b.w/day, supplemented with vitamin E (5 mg/kg b.w/day), was orally administered in two groups of heroin addict subjects consisting of in-patients (Group A, 30 males) and one of out-patients(Group B, 10 males), for a minimum of 4 weeks. The group A in-patients were also administered the conventional (diazepam + analgesic) medication. The results on the intensity of withdrawal syndrome (WS), estimated according to DMS-III criteria, were compared to a third group of heroin addict in-patients (group C, 30 males-control group), treated only by conventional medication. RESULTS: The patients of the vitamin C-treated groups (in-patients and out-patients) experienced mild WS (in 46.6% to 50% of the subjects) in contrast to the control group patients, who experienced mild WS in 6.6% of the cases. The vitamin C-treated subjects expressed major WS ranging from 10% to 16.6%, in contrast to the untreated subjects (control group), who expressed a major WS in 56.6% of the cases. CONCLUSIONS: The results indicate that high doses of ascorbic acid administered orally, may ameliorate the withdrawal syndrome of heroin addicts. Further studies are needed in order to estimate the dose- and time-dependent effects of ascorbic acid treatment, and to clarify its mechanisms of action in the withdrawal syndrome.

Lead and cadmium in eggs of colonially nesting waterbirds of different position in the food chain of Greek wetlands of international importance.

Lead and cadmium concentrations were measured in eggs of collonially nesting waterbirds with different position in the food chains of Greek wetlands of international importance. Differences were found between species in the levels of both lead and cadmium in the Evros and Axios Deltas attributable to their different diets. Nevertheless, the concentration in eggs was unrelated to the position of each species studied in its food chain. There was no significant difference in lead levels among four wetlands sampled for the cormorant and in Cd levels among three wetlands sampled for the Mediterranean gull, probably implying species-specific accumulation patterns. A higher lead pollution of the Axios Delta area was only reflected in the eggs of the Mediterranean gull. The very low concentrations of both metals found in the eggs may either suggest low environmental inputs or lack of sensitivity in using eggs as lead and cadmium biomonitors, thus a more sensitive bioindicator still remains to be found.

Electrocardiographic alterations induced by zinc ions on isolated guinea pig heart preparations.

On guinea pig isolated hearts perfused according to the Langendorff technique, by Chenoweth's solution, and by various concentration of ZnCl2, surface E.C.G. was recorded for 65 min, after the equilibration period. Concentrations of zinc corresponding to plasma free and exchangeable fractions (1.5 microM) exerted only a nonstatistically significant sinus bradycardia. Bradycardia was prominent between the 25th and 35th min of perfusion, with higher concentrations of zinc (7.5 and 15 microM). In even higher (toxic) concentrations of zinc (30 microM), various types of arrhythmias were recorded, such as first degree AV block, idioventricular rhythms, atrial, and ventricular extrasystoles, and asystolia, evoked since the 15th min of perfusion. The above-mentioned findings in relation to low plasma zinc concentrations found in coronary patients and experimental myocardial infarction as well as myocardial injury related to metal fume fever, brought our attention to the involvement of this divalent cation to cardiac physiology and pathophysiology.

Atrial natriuretic peptide and thyroid hormones' relation to plasma and heart calcium and magnesium concentrations of Wistar rats exposed to cold and hot ambients.

Plasma ANP (atrial natriuretic peptide), thyroid hormones, and calcium and magnesium levels as well as heart tissue calcium and magnesium concentrations were determined in male Wistar rats after exposure of 114 rats at low temperature (4 degrees C) and 95 rats at high temperature (35-36 degrees C) for 28 d. Plasma ANP, triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), free T3, and free T4 were estimated by radioimmunoassay, and plasma and heart tissue levels of Ca and Mg by flame atomic absorption spectrophotometry. Results were compared to a control group exposed at 20-22 degrees C (76 rats). All the above parameters in control rats did not show statistically significant variations during the study. A significant increase of plasma ANP, T3, T4, Ca, and Mg concentrations developed during cold exposure, whereas a gradual decrease of plasma ANP, T3, T4, and Mg concentrations was revealed during hot exposure. A significant increase of heart tissue Mg concentrations developed during hot exposure. Results also indicate that plasma ANP and T3 levels are proportionally related, whereas an inverse relationship exists between plasma ANP and T3 levels and heart Mg concentrations, in both cold and hot exposed rats. In conclusion, ANP and thyroid hormones in relation to Ca and Mg play an important role in temperature adaptation.

Inhibition of PAF-acether effects on isolated guinea pig hearts by zinc ions (Zn2+).

PAF-acether is a phospholipid synthesized by most animal tissues and exerting a strong decrease on the heart's contractile force and coronary flow. PAF-acether (10(-9) and 10(-10)M) was administered to isolated guinea pig hearts perfused via the Langendorff apparatus with Chenoweth solution. Zinc (1.5 microM) is known to benefit heart function thus, Zn2+ (1.5, 7.5, and 30 microM) was added in the perfusing solution before or after PAF-acether administration. Contractile force, coronary flow, and heart rate were recorded by means of a Narco MK-IV Physiograph throughout all modes of perfusion. Calcium inhibitor (Verapamil 10(-10)M) and Pb+2 Co2+ (1.5 x 10(-6)M) were used subsequently in the perfusing solutions in order to elucidate some of the Zn and PAF interactions observed. All hearts were analyzed for their Zn and Ca content by means of an Atomic Absorption Spectrophotometry (AAS). Our data suggest that low concentrations of zinc (1.5 microM) can strongly inhibit PAF-induced decrease of contractile force and coronary flow. Zinc-inhibiting effects on PAF's negative inotropic action (myocytic level) is not exerted through Zn-Ca antagonism. Nevertheless, a Zn-Ca antagonism in the arteriolar level cannot be excluded. Zinc inhibits PAF selectively only if it is administered before PAF injection and this strongly suggests a receptor interaction between the metal and the phospholipid at the heart level.

The effects of Zn2+ on guinea pig isolated heart preparations.

Isolated guinea pig hearts were perfused, by the Langendorff technique, with 30, 15, 7.5, and 1.5 microM Zn2+ in Chenoweth solution. Contractile force, coronary flow, and heart rate were recorded by means of Narco IV Physiograph. Calcium inhibitor (Verapamil 1 microM) and anion inhibitor (DIDS: 0.1, 1, and 5 microM) were used subsequently in the perfusing solutions in order to distinguish some of the possible mechanisms that Zn2+ uses to exert its action on cardiac myocytes. Isomolar to zinc concentration of Pb (II) and Co (II) were used to elucidate whether zinc effects on heart are specific for this metal. All hearts were used to estimate their zinc and calcium content by means of AAS (Atomic Absorption Spectrometry). Our findings suggest that the higher the Zn2+ concentration, the more toxic effects on heart are expressed by rapid reversible contractile force reduction and reversible specific changes of heart rate and flow. Zinc 1.5 microM in the perfusing solution benefits heart performance, but not significantly. Furthermore, the metal exerts specific effects on guinea pig heart, and it is rather possible that these effects on cardiac myocytes are held through cell membrane receptors.

Separation of the nucleus from the cytoplasm of frog, chicken and trout erythrocytes by means of high doses of vitamin B12.

The effect of high doses vitamin B12 on the nucleus-bearing erythrocytes in the peripheral blood of the frog, chicken and trout has been investigated. The i.p. and i.m. injection of 5 mg B12/animal, caused the separation of the nucleus from the cytoplasm of the erythrocytes to various degrees. The most pronounced effect was observed in trouts, where 75% of the erythrocytes lost their cytoplasm. Frog and chicken were less susceptible to the denucleating effect of B12. About 10-15% of the frog and chicken erythrocytes lost their cytoplasm 7-8 weeks after the B12 injection.

Human bladder urine oxygen content: implications for urinary tract diseases.

Urine dissolved oxygen (DO) was measured in 40 healthy subjects and 115 patients divided into 4 groups according to their disease. Group 1 (20 patients) had lower urinary tract infection (UI), Group 2 (30 patients) had urinary stone disease (USD), Group 3 consisted of 50 end-stage chronic renal failure patients (CRF) and 15 patients in Group 4 were affected by influenza viral infection (IVI). Urinary and arterial PO2, PCO2 and pH were also measured in 20 healthy subjects. The other 20 healthy volunteers were subjected to submaximal exercise and afterwards urinary DO was estimated. Results revealed that in healthy subjects urinary DO or PO2 is not correlated with urinary pH or arterial pH, PO2 and PCO2. Also, urinary DO did not significantly vary on consecutive days. Urinary DO reflects mainly the renal metabolic state, being increased in conditions of decreased kidney metabolism such as CRF. Submaximal physical exercise, fever or urinary tract infection may significantly reduce urinary DO, whereas DO remains unaffected in uncomplicated USD. Human urinary DO is related to serum creatinine and urine volume. Our results indicate that urinary DO may be a useful indicator in clinical practice.

Intra-peritoneal application of catechins and EGCG as in vivo inhibitors of ozone-induced oxidative stress.

Oxidative stress is considered as a prominent feature of many acute and chronic diseases as well as of the normal aging process. We examined the effects of intra-peritoneal administration of catechins and EGCG as in vivo inhibitors of oxidative stress induced by ozone administration in two groups of Wistar rats. The first group was treated by intra-peritoneal administration of catechins and EGCG after the administration of ozone and the second group was pretreated by intra-peritoneal administration of catechins and EGCG prior to ozone administration. We determined in blood the activity of the enzymes superoxide dismutase and glutathione peroxidase, total antioxidant capacity, levels of copper and zinc and in urine malonaldehyde contents. Ozone administration resulted in significant reduction of glutathione peroxidase activity, plasma zinc levels and plasma and Red Blood Cells antioxidant capacity. Catechins and EGCG upregulate superoxide dismutase activity and maintain plasma and Red Blood Cells antioxidant capacity. Malonaldehyde levels at the end of the study were significantly increased only in the first group. Our data demonstrate that treatment with catechins and EGCG cannot reverse or prevent the effects of oxidative stress although some modulation occurs.

Selenium in serum and neoplastic tissue in breast cancer: correlation with CEA.

Trace element selenium (Se) is regarded to be a breast cancer preventive factor involved in multiple protective pathways. In all, 80 women with breast cancer who underwent a radical mastectomy were enrolled in the study. Serum Se and carcinoembryonic antigen levels were measured using a fluorometric and IRMA assay, respectively. Se tissue concentration was determined by a tissue extracting fluorometric assay. For statistical analysis purposes t-test was used and P-values <0.001 were regarded as statistically significant. Serum Se was 42.5+/-7.5 microg l(-1) in breast cancer patients and 67.6+/-5.36 microg l(-1) in the age-matched control group of healthy individuals. Serum carcinoembryonic antigen in patients was 10+/-1.7 U ml(-1) (normal <2.5 U ml(-1) in nonsmokers/<3.5 U ml(-1) in smokers). A statistically significant difference was found for both serum Se and CEA between two groups studied (P<0.001). Neoplastic tissue Se concentration was 2,660+/-210 mg g(-1) tissue; its concentration in the adjacent non-neoplastic tissue was 680+/-110 mg g(-1) tissue (P<0.001). An inverse relationship between Se and CEA serum levels was found in the two groups studied (r=-0.794). There was no correlation between serum/tissue Se concentration and stage of the disease. The decrease in serum Se concentration as well as its increased concentration in the neoplastic breast tissue is of great significance. These alterations may reflect part of the defence mechanisms against the carcinogenetic process.

Anionic mechanisms of zinc uptake across the human red cell membrane.

1. Zinc is taken up into human red cells by two mechanisms that depend upon the presence of anions. One of these requires bicarbonate ions, is inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) and appears to be catalysed by the anion exchanger. The second occurs in the presence of thiocyanate or salicylate ions and may represent transport of a neutral complex with Zn2+. 2. The initial rate of Zn2+ uptake via the anion exchanger is 64 +/- 13 mumol (10(13) cells x h)-1 microM-1 external Zn2+, in the presence of 5 mM-bicarbonate at pH 7.4 and 37 degrees C (+/- S.D.). This is about 1/250 of the corresponding rate of Pb2+ uptake by the anion exchanger. 3. The variation of transport with Zn2+ concentration, HCO3- concentration and pH suggests that the transported species may be ZnCO3Cl- or Zn(HCO3)Cl.OH-. 4. Zinc efflux could not be observed by either of the above routes. This observation suggests that the intracellular free Zn2+ concentration is below 3 nM.

[Results of treatment of cystinuria and cystine lithiasis with alpha-mercaptopropionylglycine. Apropos of 40 patients]. / Résultats du traitement de la cystinurie et de la lithiase cystinique par l'alpha-mercaptopropionylglycine. A propos de 40 patients.

From 1987 to 1990, 719 subjects (385 males and 334 females) were screened, by means of urocystin-kit, for cystinuria and cystine lithiasis, in Epirus district (North-West Greece). The positive results were confirmed by chromatographic analysis of urine amino acids and laboratory tests. Forty patients, belonging to six cystinuric families, were identified. These patients were excreting 3.1 +/- 1.7 mmol/24 h of cystine in urine. All patients were treated by per os administration of alpha-MPG in daily doses of 400-1,200 mg/24 h). We therefore report the results of a 4 +/- 2 year follow-up of these patients. We conclude that treatment with alpha-MPG is very effective with minimal side effects in patients suffering from cystinuria or cystine urinary calculi.