Selenium and zinc in patients with acute and chronic uveitis.

Patients with chronic inflammation often show decreased serum levels of trace elements. This study aimed to investigate serum levels of selenium and zinc in patients with uveitis. Twenty-four patients (13 female, 11 male) with a mean age of 40.6 +/- 15.5 yr were included in this study. According to their underlying disease, they were divided into acute (n = 13) or chronic (n = 11) uveitis. Selenium and zinc determination was performed by atomic absorption spectroscopy in EDTA blood samples. Patients with acute or first-time uveitis showed selenium and zinc concentrations within the normal range. In contrast to this, patients with chronic recurrent uveitis tend to result in decreased selenium and zinc levels. Especially selenium showed a remarkable reduction in serum concentration below the normal range. Furthermore, there was a tendency to decreased trace element concentrations with increasing age. A sex dependency could not been found. Especially patients with chronic, recurring uveitis show remarkable decreased selenium concentration in the EDTA-blood. Further studies should investigate possible positive effects of therapeutic selenium and zinc supplementation in patients with chronic, recurrent uveitis.

[Selenium and cataract--risk factor or useful dietary supplement?]. / Selen und Katarakt--Risikofaktor oder sinnvolle Nahrungsergänzung?

BACKGROUND: The exact role of selenium in cataract development is still unclear. Both protective and toxic effects and mechanisms have been postulated in the past. Accordingly, the selenium contents in human lenses and blood sera in different forms of cataract were investigated. METHODS: 123 patients (76 female and 37 male) with a mean age of 69.8 years (range: 17 to 91 years) were enrolled in this study. Overall, 84 lenses (after ECCE) and 110 blood serum samples were investigated by atomic absorption spectroscopy. Interpretation of data was accompanied by exact preoperative investigations including Scheimpflug techniques. RESULTS: A significant increase of selenium content of the lenses was found with increasing lens opacification and colouration. Lenses with a mature cataract showed the highest selenium contents in the lens compared to other cataract forms. Opposite results were detected in blood serum. Lenses of diabetics showed already at a younger age changes in selenium content. Smokers showed both decreased selenium contents in the lens and decreased selenium concentration in blood serum. CONCLUSIONS: An obvious correlation between the type of cataract and selenium content of the lens seems to exist. The question by which mechanism selenium acts directly or by selenium-dependent enzymes acts lens opacification remains speculative up to now.

Antioxidant status in acute stroke patients and patients at stroke risk.

BACKGROUND AND PURPOSE: Antioxidant enzymes like copper/zinc superoxide dismutase (SOD), catalase and gluthatione peroxidase (GSHPx) are part of intracellular protection mechanisms to overcome oxidative stress and are known to be activated in vascular diseases and acute stroke. We investigated the differences of antioxidant capacity in acute stroke and stroke risk patients to elucidate whether the differences are a result of chronic low availability in arteriosclerosis and stroke risk or due to changes during acute infarction. METHODS: Antioxidant enzymes were examined in 11 patients within the first hours and days after acute ischemic stroke and compared to risk- and age-matched patients with a history of stroke in the past 12 months (n = 17). Antioxidant profile was determined by measurement of glutathione (GSH), malondialdehyde (MDA), SOD, GSHPx and minerals known to be involved in antioxidant enzyme activation like selenium, iron, copper and zinc. RESULTS: In comparison to stroke risk patients, patients with acute ischemic stroke had significant changes of the GSH system during the first hours and days after the event: GSH was significantly elevated in the first hours (p < 0.01) and GSHPx was elevated 1 day after the acute stroke (p < 0.05). Selenium, a cofactor of GSHPx, was decreased (p < 0.01). GSHPx levels were negatively correlated with National Institutes of Health Stroke Scale (NIHSS) scores on admission (r = -0.84, p < 0.001) and NIHSS scores after 7 days (r = -0.63, p < 0.05). MDA levels showed a trend for elevation in the first 6 h after the acute stroke (p = 0.07). No significant differences of SOD, iron, copper nor zinc levels could be identified. CONCLUSIONS: Differences of antioxidant capacity were found for the GSH system with elevation of GSH and GSHPx after acute stroke, but not for other markers. The findings support the hypothesis that changes of antioxidant capacity are part of acute adaptive mechanisms during acute stroke.

Increased content of zinc and iron in human cataractous lenses.

The purpose of the study was to examine the zinc and iron content of human lenses in different types of cataract and to investigate the possible influence of diabetes on the zinc and iron content of the lens. Iron and zinc of 57 human lenses (28 corticonuclear cataracts and 29 mature cataracts with a mean age of 70.6 +/- 16.1 and 74.7 +/- 11.1 yr, 41 nondiabetics and 16 diabetics) were determined by atomic absorption spectroscopy. The zinc content of human lenses was significantly increased in mature cataracts compared to corticonuclear cataracts (0.51 +/- 0.33 vs 0.32 +/- 0.20 micromol/g dry mass, p=0.012). The iron content of mature cataracts was also higher than in corticonuclear cataracts (0.11 +/- 0.09 vs 0.07 +/- 0.05 micromol/g dry mass, p=0.071). Furthermore, a significant increase of the lens zinc content could be observed with increasing lens coloration (light brown 0.33 +/- 0.17 vs dark brown 0.52 +/- 0.35 micromol/g dry mass, p=0.032). Diabetic patients seem to have both increased zinc and iron contents in the lens compared to nondiabetic subjects (zinc: 0.45 +/- 0.42 vs 0.40 +/- 0.22 micromol/g dry mass; iron: 0.12 +/- 0.10 vs 0.08 +/- 0.05 micromol/g dry mass). These data suggest a possible influence of the lens zinc and iron content on the development of lens opacification. Especially advanced forms of cataract and dark brown colored lenses show significantly increased zinc and iron content.

LLU-alpha, an endogenous metabolite of gamma-tocopherol, is more effective against metal nephrotoxicity in rats than gamma-tocopherol.

Antioxidants of the vitamin E family have protective effects against metal toxicity. We examined the protective effect of racemic LLU-alpha [2,7,8-trimethyl-2-(carboxyethyl)-6-hydroxychroman] a metabolite of gamma-tocopherol, in comparison to the effect of alpha- and gamma-tocopherol in rats treated with sodium dichromate (Cr) or thallium sulfate (Tl). We measured metal nephrotoxicity based on urinary protein excretion and discussed it with respect to the metal concentration in renal tissue. The ranking of antioxidant activity (iron stimulated lipid peroxidation, luminol and lucigenin amplified chemiluminescence) was determined in the following order: alpha-tocopherol

Oral zinc therapy in patients with supposed mild zinc deficiency--a critical review.

The importance of zinc in many processes of diseases remains unclear up today. Nevertheless many biochemical or clinical studies let support a high clinical relevance of trace elements especially zinc in the therapeutic concepts of diseases. Unfortunately the border between severe (or real) and mild (or subclinical) zinc deficiency is not clear defined. In addition methodical problems in determination of trace elements and misinterpretations of study results lead to unjustified assignment from several diseases in the group of zinc deficiency disorders. Another current problem is the consideration of bioavailability of oral commercial trace element products. Especially the regulation of zinc uptake in human under normal conditions and in case of zinc deficiency is not clear at this time. These problems let become tangled the actual literature for the clinical active physician at the field of zinc. In this mini review there is given an overview about published clinical studies with oral zinc supplementation in the past years.

Determination of iron, copper, zinc, magnesium and selenium in plasma and erythrocytes in neurosurgical patients.

A direct method for determination of Fe, Cu, Zn, Mg and Se in erythrocytes was developed. The aim of the present study was to establish a method for examining perioperative levels of the above mentioned elements simultaneously in erythrocytes and plasma by atomic absorption spectrophotometry in 11 patients undergoing neurosurgery for acute spinal nerve compressions because of intervertebral disk prolapses. Reference values for erythrocytes were 11.49 +/- 3.48 mmol/mmol Hb; 0.82 +/- 0.087 mmol/mmol Hb; 9.01 +/- 2.20 mmol/mmol Hb; 0.104 +/- 0.032 mmol/mmol Hb; 0.07 +/- 0.050 mmol/mmol Hb for iron, copper, zinc, magnesium, and selenium, respectively. Postoperative erythrocyte concentrations did not differ significantly compared to those obtained preoperatively and remained within the reference ranges perioperatively. For plasma the following reference values were used: 19.0 +/- 8.0 mmol/l (Fe); 20.1 +/- 8.2 mmol/l (Cu); 15.4 +/- 4.6 mmol/l (Zn); 0.9 +/- 0.15 mmol/l (Mg); 1.02 +/- 0.3 mmol/l (Se). There was a significant decrease in the concentration of copper in plasma (13.41 +/- 3.46 mmol/l, p < 0.1) and zinc (10.73 +/- 2.73 mmol/l, p < 0.1) immediately postoperative, iron (10.56 +/- 3.91 mmol/l, p < 0.1) and zinc on day 1 (11.28 +/- 1.88 mmol/l, p < 0.10), and a significant postoperative increase of copper on day 5 (18.81 +/- 3.97 mmol/l, p < 0.1), postoperatively. The mean plasma concentrations of iron, copper, zinc magnesium and selenium remained within the reference ranges during the entire period.

Effect of intravenous magnesium on ventricular tachyarrhythmias associated with acute myocardial infarction.

Ventricular ectopy and left ventricular dysfunction are important predictive factors for an unfavourable outcome following an acute myocardial infarction (MI). Tachyarrhythmias are a major cause of death subsequent to MI. Magnesium was postulated to have an antiarrhythmic effect after MI. Therefore we have investigated the influence of intravenous and oral magnesium (Mg) therapy on ventricular tachyarrhythmias. 67 patients with myocardial infarction (MI) diagnosed according to the WHO criteria of anamnesis, infarct-specific electrocardiogram (ECG), and enzymatic status were included in a prospective study. 23 patients (group 1) received 2 g Mg per day (= 82 mmol Mg/24 h) intravenously for the first 3 days followed by oral magnesium adipate administration of 3 x 2 coated tablets of magnesium 50 Apogepha (= 300 mg Mg/24 h or 12.34 mmol Mg/24 h, respectively) for the full duration of the study. 26 patients (group 2) received only i.v. magnesium for the first 3 days after admission (2 g Mg/24 h). The results of this treatment were compared to those of a control group of 18 MI patients without magnesium administration. All groups were identical with regard to other forms of treatment. The magnesium levels in serum and erythrocytes of all patients were measured at the following time points: days 0 (admission time), 1, 2, the day of discharge (about day 20) and after 12 weeks. The tachyarrhythmias were monitored by 24-h-continuous-electrocardiography on days 0, 1 and on the day before discharge (about day 20). The serum magnesium levels rose significantly during i.v. Mg-administration (1 and 2 day) but decreased in group 2 subsequently until the time of discharge from hospital. In contrast group 1 patients receiving oral as well as intravenous magnesium did not show this drop. The uptake of magnesium into the erythrocytes was less obvious. The erythrocyte magnesium concentration of the control group remained significantly low in serum and red blood cells. Significantly less ventricular premature beats and runs (< 5 ventricular premature beats and > 5 ventricular premature beats) compared to admission day were observed in both treated groups. These data suggest that the frequency of ventricular tachyarrhythmias is reduced by administration of intravenous magnesium and support an early high dose administration of intravenous magnesium in the wake of myocardial infarction.

Kinetics of chromium(V) formation and reduction in fronds of the duckweed Spirodela polyrhiza--a low frequency EPR study.

The uptake of chromate by the duckweed Spirodela polyrhiza was investigated with atomic absorption spectroscopy and the reduction of Cr(VI) to Cr(V) was measured using low frequency EPR spectroscopy. The biphasic kinetics of the uptake was fitted to parameters of a proposed kinetic model. Another model was developed to simulate chromate reduction. The first step of chromate reduction was found to be much faster than the uptake of Cr(VI) from the free space. Most probably, this step occurs already in the cell wall or on the cell membrane surface. Further reduction of Cr(V) to Cr(III) was estimated to be slower. The disappearance of the Cr(V) signal, following transfer of the plants into a Cr-free solution, lasted several tens of hours; the kinetics was mono- or biexponential depending on the length of Cr loading. The rate constants for Cr reduction in living plants were determined for the first time.

[Effect of administration of selenium and vitamin E on heart failure and ventricular arrhythmias in patients with acute myocardial infarct]. / Einfluss der Substitution von Selen und Vitamin E auf Herzinsuffizienz und ventrikuläre Herzrhythmusstörungen bei Patienten mit akutem Myokardinfarkt.

PATIENTS AND METHOD: Patients with acute myocardial infarction were treated with selenium and vitamin E as antioxidants in addition to the standard therapy. They were compared to a reference group which received no additional therapy. It was to be investigated whether selenium and vitamin E are able to positively influence the course of the infarction, measured by way of the insufficiency symptoms, ventricular cardiac arrhythmia in long-term ECG and the ejection fraction determined by echocardiography. The concentrations of selenium, malonic dialdehyde (TBARS), glutathione peroxidase and vitamin E were measured at various points in time. RESULTS: During the course of the in-patient treatment, significant percentage increases in selenium, glutathione peroxidase and vitamin E were detected. Group differences were similarly significant. It was not possible to detect differences in the clinical parameters. Possible explanations to be discussed are the duration of the treatment, the times of the examinations and the different proportions of patients treated thrombolytically in the 2 groups.

[Coronary angiography and change in antioxidative status]. / Koronarangiographie und Veränderung des antioxidativen Status.

PATIENTS AND METHODS: In a prospective study in 53 patients with stable angina pectoris symptoms the antioxidant status (glutathione peroxidase, glutathione, superoxid dismutase, malondialdehyde and selenium in serum and whole blood) was determined before and 4 to 6 hours after coronary angiography. According to the results of the coronary angiography the patients were classified in a group with "severe" (n = 16) and another with "moderate" coronary alterations. RESULTS: In both groups there was a significant reduction of selenium in serum and whole blood. The enzymes glutathione peroxidase and superoxide dismutase as well as glutathione and malondialdehyde changed only slightly. CONCLUSION: These results can be the cause of an increase of the formation of free radicals during coronary reperfusion (PTCA, implantation of stents in the group with "severe" coronary alterations) but could also be seen as a sign of formation of radicals by the method itself (in patients with "moderate" coronary alterations). Further investigations are indicated. Furthermore the amelioration of the antioxidant status of the organism by scavenger substances (vitamins A, B, C and selenium) should be discussed.

[Reference ranges of antioxidant parameters in whole blood (erythrocytes) in a Thüringen region]. / Referenzbereiche antioxidativ wirkender Parameter im Vollblut (Erythrozyten) einer Thüringer Region.

BACKGROUND: The oxidant stress is characterized by measurement of the activities of glutathione peroxidase, superoxiddismutase and also by concentrations of glutathione and selenium in erythrocytes. A standardization of the methods of determination is very important. MATERIAL AND METHODS: In erythrocytes of blood donors (n = 101) the parameters glutathione peroxidase, glutathione, superoxiddismutase and selenium were determined. RESULTS: The following results of the antioxidant parameters in erythrocytes of blood donors were found: Selenium 67.1 +/- 20.1 nmol/mmol Hb, glutathione peroxidase 842 +/- 290 U/mmol Hb, glutathione 108 +/- 48 mumol/mmol Hb, superoxiddismutase 15.8 +/- 6.4 U/mumol Hb. CONCLUSION: Selenium, glutathione peroxidase, glutathione and superoxiddismutase in erythrocytes of blood donors are normally distributed. There are no significant differences between men and women. The use of "own reference values" is necessary because no standardization of the methods of determination exists.

Is thallium-induced nephrotoxicity in rats connected with riboflavin and/or GSH?--reconsideration of hypotheses on the mechanism of thallium toxicity.

Adult female Wistar rats (Han:Wist) were injected with 2 mg of Tl2SO4 per 100 g body weight. Parameters of nephrotoxicity were urinary volume and protein excretion as well as blood urea nitrogen concentration. Thallium concentrations were determined in renal cortex and medulla. There was no effect of different schedules of vitamin B2 (riboflavin) treatment on thallium nephrotoxicity. Glutathione (GSH) concentration was not decreased by thallium in renal cortex or in medulla. The increase of GSH concentration in renal tissue by N-acetylcysteine pretreatment did not influence thallium nephrotoxicity. Buthionine sulphoximine diminished thallium nephrotoxicity by a significant decrease of thallium concentration in renal medulla, which was caused by enhanced urinary excretion of thallium. From our investigations we conclude that there is no relation between thallium-induced nephrotoxicity and riboflavin and/or GSH.

Vitamin E and C in the prevention of metal nephrotoxicity in developing rats.

The protective effect of vitamin E and C on sodium chromate (Cr) and thallium (Tl) induced nephrotoxicity was tested in 10- and 55-day-old rats. The concentrations of Cr and Tl were determined in renal cortex and medulla by atomic absorption spectrometry. Urinary volume and protein excretion as well as blood urea nitrogen (BUN) concentration were determined as parameters of nephrotoxicity. Cr and Tl induced nephrotoxicity was significantly more expressed in adult than in young rats. In Cr and Tl nephrotoxicity the protective effect of vitamin E was evident in both age groups. Vitamin E decreased Tl concentration in renal tissue. Therefore its protective effect is not to be attributed to its known antioxidant effect but to lower Tl concentration in renal tissue. Vitamin C was protective in Cr and Tl induced nephrotoxicity in adult rats without influence on metal concentrations in renal tissue. The dose necessary for protection against toxic Cr action in adult rats was not tolerated by young rats. The combined administration of both vitamins abolished the protective effect against Cr nephrotoxicity of the administration of each vitamin alone in adult rats. When vitamin E and C were administered in Tl treated adult and young rats the protective effect was the same as after the administration of each vitamin alone. Possible mechanisms are discussed.

Protective effects of vitamin E and C on cisplatin nephrotoxicity in developing rats.

The kinetics of vitamin E was followed in serum, liver and kidney of 10- and 55-day-old rats after the administration of a single i.m. dose of 100 mg alpha-tocopherol acetate/100 g body wt. The basal levels without vitamin E administration were significantly higher in serum and liver of 10- than 55-day-old rats. The effect of vitamin E on cisplatin (CP; 0.6 mg/100 g body wt., i.p.) nephrotoxicity was investigated by determining urinary volume and protein excretion, as well as the concentration of blood urea nitrogen (BUN) and lipid peroxides in renal tissue (LPO). Previously described age differences in CP nephrotoxicity were confirmed. The administration of vitamin E, 12 h prior to CP, diminished the toxic effect of CP in young and adult rats. This effect could not be enhanced by a second administration of vitamin E. The simultaneous administration of vitamin E and C 12 h prior to CP intensified the protective effect of a single administration of vitamin E in 10- and 55-day-old rats without influencing the concentration of platinum in renal tissue.

[Selenium substitution in acute myocardial infarct]. / Selensubstitution bei akutem Myokardinfarkt.

BACKGROUND: Previous examinations have demonstrated decreased selenium levels in serum and full blood in patients with myocardial infarction. PATIENTS AND METHOD: 28 patients received a selenium treatment additional to the usual treatment of myocardial infarction. 19 patients with myocardial infarction with no supplementary selenium treatment served as a control group. Selenium levels in serum, full blood and urine were measured and the complications of the myocardial infarction documanted. RESULTS: There was a significant increase of serum and full blood selenium and glutathione peroxidase levels under i.v. selenium therapy in the acute phase of myocardial infarction (first to third day). Left heart failure more rarely occurred in the selenium group (20%) than in control patients (57%). Acute tachycardial cardiac rhythm disturbances such as ventricular extrasystoles and couplets diminished in both groups; ventricular extrasystoles decreased in the selenium group. CONCLUSIONS: Selen should be substituted in patients with acute myocardial infarction and decreased selen levels. It would be useful to carry out a prospective double-blind study.

[Selenium in phenylketonuria patients. Effects of sodium selenite administration]. / Selen bei Phenylketonuriepatienten. Effekte einer Natriumselenitsubstitution.

PATIENTS AND METHOD: 17 patients (8 female, 9 male; age 8.2 +/- 3.7 years) with phenylketonuria under phenylalanin restricted diet were investigated prior to and after 3 months of selenium substitution (sodium selenite, 115 micrograms Se/m2 BSA/d). Different parameters in blood were determined: selenium, glutathione peroxidase (Gpx) activity, thyroid hormones, blood cell count, lymphocytic antigen expression, muscle function and -enzymes, cardiac ultrasound. RESULTS: The main significant results of selenium substitution are: increased plasma-selenium, blood cell selenium, plasma-Gpx activity and left ventricular cardiac index as well as decreased plasma thyroxin, free thyroxin, reverse triiodthyronin, total cholesterol, mean erythrocyte and thrombocyte volume and lymphocytic CD2 expression. CONCLUSION: The data indicate metabolic and functional signs of selenium deficiency in patients with phenylketonuria without selenium substitution. We conclude that, despite of lacking clinical symptoms, a selenium supply in phenylketonuria patients under diet is necessary and should be performed with usefull peroral sodium selenite (115 micrograms Se/m2 BSA/d) initially, followed by a dosage between 30 and 60 micrograms Se/m2 BSA/d).

[Levels of antioxidants after cesarean section and administration of Multibionta N, Inzolen and selenase]. / Das Verhalten von Antioxidanzien nach Schnittentbindung und Substitution von Multibionta N, Inzolen und selenase.

PATIENTS AND METHOD: In 29 women with the necessity to terminate pregnancy via Cesarean section, lipid peroxidation and antioxidative state were investigated before and 24 hours after the surgical intervention as well as after substitution of antioxidants and trace elements. RESULTS: The results indicate that administration of antioxidants protects at least partially from consequences of surgically induced oxidative burden.