Protective effects of green tea on intestinal ischemia-reperfusion injury.

OBJECTIVE: The intestinal mucosa is known to be adversely affected by ischemia-reperfusion (I/R). Previously we showed that green tea protects the intestinal mucosa from fasting-induced damage. The aim of this study is to determine whether green tea has any protective role in I/R of the intestine. METHODS: Three groups of male rats were used in this study. Group I (I/R) underwent I/R of the intestine (30 min of ischemia followed by 1 h of reperfusion). Group II (green tea + I/R) was given green tea for 2 wk before inducing I/R. Group III (control) had sham I/R. After the experiments, the jejunum was removed and the tissues were processed for histopathologic examination and immunohistochemical analysis for cell proliferation markers and antioxidant enzymes. RESULTS: The intestinal mucosa in group II was preserved compared with that in group I. The expressions of cellular proliferation markers (proliferating cell nuclear antigen and Ki-67) and cellular antioxidants (superoxide dismutase and catalase) in group II were similar to those in group III and much less than in group I, reflecting the protective effects of green tea in group II animals. CONCLUSION: In this animal model, administration of green tea before inducing I/R protects the intestinal mucosa from injury.

Fasting-induced intestinal damage is mediated by oxidative and inflammatory responses.

BACKGROUND: Green tea has been shown to repair fasting-induced mucosal damage in rat intestine. The aim of this study was to elucidate the underlying mechanism. METHODS: Five groups of rats were used. Group 1 had free access to chow diet and water, and those in group 2 were fasted for 3 days. Animals in group 3 were fasted for 3 days, then were allowed drinking water for a further 7 days. Groups 4 and 5 were fasted for 3 days, then given drinking water containing green tea or vitamin E respectively for 7 days. Blood was collected for estimation of total plasma antioxidants, and jejunal samples were used for immunohistochemical analysis of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx), and for estimation of myeloperoxidase (MPO) activity. RESULTS: Use of green tea was associated with a significant increase in total plasma antioxidants (P < 0.001), and mucosal SOD (P < 0.001), catalase (P = 0.006) and GPx (P = 0.017), but a significant decrease in MPO activity (P < 0.001). Vitamin E produced similar changes, but the effects were smaller. CONCLUSION: Green tea reverses the fasting-induced damage to the intestinal mucosa by its antioxidant and anti-inflammatory effect.

Homologous blood transfusion is not required in surgery for adolescent idiopathic scoliosis.

We studied 70 consecutive patients with adolescent idiopathic scoliosis who underwent corrective surgery. They were divided into two groups. In the study group of 38 patients one or more modern blood-conservation measures was used peri-operatively. The 32 patients in the control group did not have these measures. Both groups were similar in regard to age, body-weight, the number of levels fused and the type of surgery. Only two patients in the study group were transfused with homologous blood and these transfusions were 'off-protocol'. Wastage of autologous pre-donated units was minimal (6 of 83 units). By contrast, all patients in the control group were transfused with homologous blood. In the study group there was a significant decrease (p = 0.005) in the estimated blood loss when all the blood-conservation methods were used. The use of blood-conservation measures, the lowering of the haemoglobin trigger for transfusion and the education of the entire team involved in the care of the patient can prevent the need for homologous blood transfusion in patients undergoing surgery for adolescent idiopathic scoliosis.

Transport kinetics of zinc, copper, selenium, and iron in perfused human placental lobule in vitro.

Transport characteristics of essential trace elements as zinc, copper, selenium and iron have been studied in maternal-fetal direction in normal pregnancies, using in vitro perfusion of human placental lobules. Solutions of trace elements corresponding to twice the physiological concentrations were injected (100 microl bolus) into the maternal arterial perfusate. Serial perfusate samples were collected every 30 sec from venous outflows for a study period of 5 min. Concentrations of these trace elements and their transport kinetics were determined. Transport fractions (TF) of zinc, copper, selenium and iron averaged 0.21, 0.49, 0.55 and 0.10% of maternal load respectively. Other parameters such as area under the curve, clearance, elimination constant, absorption and elimination rates showed some significant differences between the various elements. Copper and selenium appear to be transported passively in maternal-fetal direction, while for iron and zinc, role of active transport for transfer across the human placental membrane cannot be discounted. We speculate that alterations in copper: zinc TR50 (transport rate for 50% efflux) and TF ratios could serve as useful indicators for assessing placental transport status of these essential elements in complicated pregnancy states.

Brain selenium accumulation in rat pups of selenium supplemented mothers.

Selenium is essential for normal mammalian development. Being a component of antioxidant enzyme, glutathione peroxidase, it plays a major role in protecting the cells from free radical damage. The level of glutathione peroxidase was directly related to the amount of selenium present in various tissues and organs. A decrease in selenium leads to various pathological changes in humans as well as in various laboratory animals. The aim of the present study was to understand whether there is an increase in the level of selenium in different brain regions of rat pups whose mothers were supplemented with selenium, either 2 or 4 mg/l of their drinking water throughout the period of their pregnancy. There was a significant increase in the level of selenium in the cerebellum, cortex and hypothalamic and hippocampal tissues of selenium supplemented mothers as compared with those of non-supplemented mothers. The brain stem of these animals did not show any significant difference in the level of selenium. Furthermore, the differences in the level of selenium between the rat pups of 2 mg/l selenium supplemented mothers and 4 mg/l selenium supplemented mothers were not statistically significant. These studies suggest that supplementation of selenium to mothers during the period of their pregnancy can selectively increase the level of this trace element in different brain regions. Further studies are necessary to understand the significance of selective accumulation of selenium in specific brain regions on brain development and function.

Maternal-fetal transport kinetics of copper, selenium, magnesium and iron in perfused human placental lobule: in vitro study.

Transport characteristics of certain inorganic elements such as copper, magnesium, selenium and iron have been studied in maternal-fetal direction in normal pregnancies, using in vitro perfusion of isolated placental lobules. Copper, selenium, magnesium and iron salts corresponding to twice physiological concentrations were injected as a 100 microl bolus, into the maternal arterial perfusate. Serial perfusate samples were collected from venous outflows for a study period of 5 min. Concentrations of various inorganic elements and their transport kinetics were determined. Transport fractions of copper, selenium, magnesium and iron averaged 0.14, 0.19, 0.06 and 0.23% of maternal load respectively. The pharmacokinetic parameters such as area under the curve, clearance, elimination constant, and time for maximum response showed some significant differences between the various elements. We speculate that copper and selenium share the same transport pathway along a concentration gradient in maternal-fetal direction, while for iron and magnesium, active transport plays a predominant role for element transfer across the human placental membrane.

Pre- and postnatal tissue selenium of the rat in the growing state.

The aim of this study is to quantify the selenium (Se) content (in microg/g) during different gestational periods in rat fetal tissues, and to follow up the changes in the Se content of the placenta, fetal head, liver and lung during gestation and postpartum periods. Locally reared virgin female Wistar rats were mated. Pregnant rats were sacrificed on days 15, 18 and 21 of pregnancy. Newborn pups at the age of 3 days and rats at the age of 1 month were also investigated. There was a gradual increase in placental and whole head Se content as gestation proceeded compared to day 15; however, the differences between the groups were not statistically significant. The liver Se content at day 18 of gestation was significantly higher than at day 21 of gestation and in rats at 3 days of age, but lower than the Se content of the liver of rats at the age of 1 month and the differences were statistically significant. The lung Se content was higher at day 18 of gestation than at day 21 and in the 3-day-old rats, and all differences between all groups were statistically significant except when the lung Se content at day 18 is compared to that of 1-month-old animals. The continuous increase in the Se content of the placental tissues and the whole head, although not significant statistically, may indicate that the fetus relies heavily on its supply of Se from the maternal blood and in part on the supply of thyroid hormones which are important for brain development, as evidence exists that T(4) and T(3) are present in the fetal brain in early fetal life before the onset of fetal thyroid function. The higher content of Se on day 18 and its decline on day 21 of gestation in the liver may imply that it is stored and being utilized partly in other tissues for other functions and particularly for thyroid hormone synthesis, metabolism and functions.

Magnesium in human semen: possible role in premature ejaculation.

Although magnesium is involved in many biological process and it is found higher levels in semen than serum, its role in human semen has not been elucidated. This investigation was conducted to evaluate the relationship between premature ejaculation and the levels of seminal magnesium. The levels of magnesium, zinc, copper, and selenium were evaluated with an atomic absorption spectrophotometer in serum and seminal plasma in 3 groups of men: (a) normal sperm parameters (15) (b) oligoasthenozoospermia (15), and genuine premature ejaculation (9). There were normal serum and semen levels of all the elements in the three groups, but significantly lower seminal plasma magnesium levels in men with premature ejaculation. The hormonal profile, body mass index (BMI) had no association with premature ejaculation. Decreased levels of magnesium gives rise to vasoconstriction from increased thromboxane level, increased endothelial intracellular Ca2+, and decreased nitric oxide. This may lead to premature emission and ejaculation processes. Magnesium is probably involved in semen transport. More research into the role of magnesium in the male physiology of reproductive tract, especially its association with premature ejaculation, is advocated.

Chronic cadmium toxicity to sperm of heavy cigarette smokers: immunomodulation by zinc.

The aim of the study was to investigate the role of zinc therapy in 125 male cigarette smokers with infertility. The mechanism involved in the zinc/cadmium relationship was evaluated through the effect of a zinc-deficient diet and supplementation on testes of male adult Sprague-Drew rats. Heavy smoking was associated with low sperm count, motility, and morphology and increased seminal cadmium levels. Zinc therapy improved sperm quality and increased seminal IL-4, but reduced TNF-alpha and IFN-gamma. A zinc-deficient diet led to high cadmium testicular accumulation comparable with those supplemented with cadmium. Cadmium had a linear correlation with TNF-alpha and IFN-gamma, but not with IL-4. Cytology of testicular aspirate and histopathology were normal in supplemented groups as in controls. These results indicate that zinc modulates the putative effect of cadmium through its enhancement of T-helper 2 cytokines expression and down-regulation of T-helper 1 cytokines.

Colitis-induced changes in the level of trace elements in rat colon and other tissues.

Trace elements constitute important prosthetic groups in a number of antioxidant enzymes which neutralize free radicals generated during inflammatory conditions such as colitis. However, the status of trace elements in colitis remains to be found. In the present study the concentrations of zinc, copper, manganese and selenium in the colon, liver and serum of rats with acetic acid (HAc)- or trinitrobenzenesulfonic acid (TNBS)-induced colitis were measured using atomic absorption spectrophotometer. Myeloperoxidase and glutathione peroxidase activities were measured spectrophotometrically. Our results show that the selenium concentration was significantly decreased by 33 and 37.5% in the colon and 69 and 78% in liver by HAc and TNBS treatment, respectively. Similarly the zinc concentration in the colon was decreased by 21 and 28% by HAc- and TNBS-induced colitis as compared to the controls, but manganese and copper, remained unaltered. The serum concentrations of copper, zinc and selenium also remained unaltered during colitis. The weight of HAc-treated rats did not decrease while there was a significant weight loss in the TNBS-treated rats. Myeloperoxidase activity was increased, whereas glutathione peroxidase activity was significantly decreased in the colon inflamed by HAc or TNBS as compared to the controls. These findings suggest that colitis induces a reduction in the tissue levels of trace elements which is independent of the way colitis is induced. Our findings of a reduction in Se and glutathione peroxidase activity together suggest that the reduction in the trace element concentrations is not due to dietary factors or malabsorption. The decrease may severely affect the antioxidant potential of the colon and therefore is a putative factor for the progression of disease.

Selenium and liver cirrhosis.

Effects of selenium deficiency, induced by thioacetamide, were investigated in rats. Thioacetamide (0.3 g/L) given in drinking water, as expected, caused a significant loss of selenium from the liver. It was accompanied by liver cirrhosis and a significant increase in the liver weight as well as liver to body weight ratio. A significant loss of selenium from spleen was also accompanied by an increase in its weight. Weights of lungs, testis and kidney, however, were not affected by thioacetamide and there was no change in their selenium content. Plasma levels of selenium were significantly reduced in the thioacetamide treated group. All these changes were confirmed to be due to selenium deficiency caused by thioacetamide, as supplementation with selenium reversed these changes. The mode of action of selenium is unknown but may involve anti-oxidant defense mechanisms.

Inflammatory response and oligo-element alterations following cardiopulmonary bypass in patients undergoing coronary artery bypass grafting.

Oligo-elements such as zinc (Zn), selenium (Se) and copper (Cu) have a significant influence on the function of the immune system. Various immunological and inflammatory changes are known to occur in patients undergoing cardiopulmonary bypass. The aim of this study was to evaluate changes in serum oligo-elements levels during and following cardiopulmonary bypass. The serum levels of Zn, Se and Cu were determined in 67 consecutive patients, with coronary artery disease admitted for coronary artery bypass grafting. Blood samples for oligo-elements, analysis were withdrawn into metal-free tubes just prior to the start of cardiopulmonary bypass; at 30, 60 and 90 min into cardiopulmonary bypass; following weaning from cardiopulmonary bypass; 30 min after termination of cardiopulmonary bypass; at 24 h; and on the 5th postoperative day. Trace elements analyses were performed using atomic absorption spectrophotometry. Interleukin 6 and 8, as well as serum albumin, creatine phosphokinase, lactate dehydrogenase and creatine phosphokinase-MB fractions were also analyzed. The mean age was 63 +/- 9 years and 91% (61) were men. The mean preoperative left ventricular function was 52 +/- 12%, Canadian Cardiovascular Society (CCS) angina class was 3.7 +/- 0.5 and 30% (20) of the operations were re-do's. All patients had normothermic cardiopulmonary bypass. Mean cardiopulmonary bypass-time was 85 +/- 31 min. One patient was lost for the recovery sampling (hospital mortality, 1.5%). Nine patients had a postoperative cardiac index < 2.0 liter/min per m2, which required pharmacological support and additional intra-aortic balloon pump in two of them. Other postoperative complications were few. There was a rapid depletion of S-selenium and S-Zn levels, which were halved at 30 min after cardiopulmonary bypass and remained low throughout the study period. The Cu/Zn ratio increased significantly at the start of cardiopulmonary bypass, which indicated an inflammatory reaction and was not normalized until the 5th postoperative day. Length of ischemia time, presence of diabetes. hypertension and hyperlipidemia did not influence the results, while a prolonged cardiopulmonary bypass-time > 120 min resulted in a higher Cu/Zn ratio than observed for shorter cardiopulmonary bypass-times. This indicates a more profound inflammatory response. Inflammatory parameters responded in the same manner as described earlier by others. These data indicate that severe loss of various oligo elements occur in patients undergoing coronary artery bypass grafting and suggests that a supplementary administration of zinc and perhaps also selenium could be appropriate during cardiopulmonary bypass.

Effect of dietary selenium, zinc and allopurinol supplements on plasma and tissue manganese levels in rats with thioacetamide [correction of thiocetamide]-induced liver cirrhosis.

The effect of thioacetamide-induced liver cirrhosis on plasma and tissue manganese levels and the protective role of selenium, zinc and allopurinol supplements was investigated in rats. Control plasma and liver manganese (Mn) levels were found to be (mean +/- SD): 8.4 +/- 2.4 mg/L and 5.7 +/- 1.5 mg/g wet weight respectively. Plasma manganese levels were significantly increased (p < 0.001) whereas liver manganese levels were significantly reduced (p < 0.05) in the cirrhotic rats. Treatment with selenium, zinc and allopurinol reversed this trend and restored the manganese levels close to the normal values. Lung, spleen, and kidney manganese levels under control conditions were considerably lower than that of the liver tissue. However, these levels registered a significant increase (p < 0.05) in cirrhotic rats and this change was normalized after selenium, zinc and allopurinol treatment. There were no significant differences in the comparative efficacy of each of these protective agents. Zinc supplement considerably increased the plasma zinc levels and plasma Zn/Mn ratio had a good correlation with plasma zinc concentration. This ratio was significantly reduced in cirrhotic rats, but returned to the control level after zinc, selenium and allopurinol treatment. The results of this study indicate that the trace element, manganese, plays an important role in stabilizing cell structure and that this effect is mediated possibly by preserving the antioxidant activity of the tissues.

Prevalence of allergic sensitization to inhalant allergens among blood donors in Kuwait--a desert country.

Kuwait is a desert country where the prevailing high temperatures, low humidity, and scant vegetation suggest a low prevalence of allergy. We evaluated the prevalence of atopic sensitization (presence of allergen-specific IgE) among young adult blood donors by screening a total of 505 subjects (male: female ratio 1.6) with mean age of 28.4 years (range 18-50 years). The Pharmacia CAP-Phadiatop test, which detects serum IgE specific to most common airborne allergens, was used. Some of the specific sensitizing allergens were also identified by the related CAP-RAST method. Sensitization was detected in 223 of the 505 subjects (44.2%) screened. Kuwaiti nationals had a significantly higher prevalence rate (50.2%) than non-Kuwaitis (34.2%) (chi 2 = 8.6, P < 0.003). The highest prevalence rate was found among male Kuwaitis (53.8%). The prevalence of current or previous allergic disease (subject-reported) was 20.6%. Bermuda grass, house-dust mite (Dermatophagoides pteronyssinus), and Chenopodium album were the most prevalent sensitizing allergens, with frequencies of 53.6%, 52.7%, and 50.9%, respectively, among the sensitized subjects (corresponding to 23.7%, 23.3%, and 22.5%, respectively) for the entire population. Sensitization increased with age, but only among the expatriates, younger Kuwaitis being as frequently sensitized as the older ones. Polysensitization was found to be common. Of the 109 CAP-RAST-positive subjects, 71 (65.1%) were sensitized to more than one allergen, and 30 of these (42.3%) were sensitized to four or more allergens. These results show that atopy is highly prevalent among young adults in Kuwait, and the higher prevalence rate among nationals than expatriates suggests the involvement of genetic or local environmental factors. The results also confirm that mite and plant pollens may be major sensitizing allergens even in a desert environment.

Significance of trace elements in seminal plasma of infertile men.

The seminal fluid has the important function as a vehicle for the transportation of the spermatozoa through the epididymis, the vas deferens, and urethra and into the vagina. Major changes in the level of trace elements like zinc, magnesium, and cadmium in semen appear to be related to abnormal spermatozoal function and fertilizing capacity. The aim of the study was to evaluate the pattern of trace elements in semen of subfertile men compared to levels in the blood. The relationship of the trace elements with spermatozoal parameters was also evaluated. As part of the infertility evaluation, semen and blood samples were collected from 50 males attending the combined infertility clinic at a maternity hospital after 3 days' abstinence. Semen analysis and hypo-osmotic swelling tests were done on fresh semen samples. The serum and remaining semen sample were stored at -20 degrees C until they were analyzed with atomic absorption spectrometry. No significant differences occurred in the levels of trace elements in normozoospermic, oligospermic, and azoospermic semen. However, significantly high levels of cadmium were detected in semen of men who were smokers and had asthenozoospermia (p < 0.001) compared with those who had normal motility. We conclude that the high level of cadmium in smokers with asthenozoospermia is evidence of the possible toxic effect of this trace element and this may be one of the causes of asthenozoospermia.

Keloid and hypertrophic scars: trace element alteration.

The state of excessive fibroblastic proliferation for wound healing results in hypertrophic and keloid scars. It has been well established that some of the trace elements (such as zinc) are essential in wound healing, and there are appreciable changes in trace elements in various disease states. The levels of zinc (Zn), copper (Cu), manganese (Mn), and selenium (Se) in serum, normal skin and scar of 40 keloid and hypertrophic scar patients were assessed. There was a significant increase of manganese (Mn) level in skin of burn, trauma, and surgical incision patients compared to controls with p < 0.0013, p < 0.0001, and p < 0.046, respectively. Furthermore, the zinc, copper, and selenium contents of the skin in incision patients were decreased significantly when compared to other groups. No significant changes occurred regarding serum levels of zinc, copper, manganese, and selenium in the different groups. From this study, no relationships between the hypertrophic and keloid scar to trace elements were found; however, because of the limited numbers of patients, a definite conclusion could not be drawn.

Interleukin-1 alpha (IL-1 alpha) production by alveolar macrophages in patients with acute lung diseases: the influence of zinc supplementation.

The relationship between zinc treatment and interleukin-1 alpha (IL-1 alpha) production by cultured alveolar macrophages (AM) in patients with pulmonary tuberculosis and bacterial pneumonia was investigated. AM (1 x 10(6) cells/ml) from 6 patients with pulmonary tuberculosis, 7 patients with bacterial pneumonia and 4 healthy volunteers were cultured with either two different concentrations of zinc chloride (Znl = 1 microgram/ml and Zn2 = 5 micrograms/ml) or cell culture media alone (control) for an initial period of 6 hours and then stimulated with 3 different immunomodulator agents and reincubated for a further 24 h. IL-1 alpha in culture supernatants was measured by enzyme-linked immunosorbent assay (ELISA). In the absence of Znl or Zn2 Polyinosinic:Polycytidylic acid (Poly I:C 1 microgram/ml), Lipopolysaccharide (LPS 100 ng/ml) and Tumour necrosis factor-alpha (TNF-alpha 10 ng/ml) significantly increased the production of IL-1 alpha from AM in both patients and healthy subjects (p < 0.001) compared to control (media only). Zn1 and Zn2 significantly increased the production of IL-1 alpha (p < 0.001) in culture supernatants in the absence of either Poly I:C, LPS or TNF-alpha in patients but not in healthy group. In contrast, the presence of LPS or TNF-alpha significantly reduced Zn1 or Zn2-stimulated release of IL-1 alpha from AM in patients and healthy subjects (p < 0.01). However, Poly I:C decreased only Zn1-stimulated release of IL-1 alpha. These results suggest that zinc can regulate the production of IL-1 alpha from AM in patients with pulmonary tuberculosis or bacterial pneumonia.

Early biochemical and histological changes in rats exposed to a single injection of thioacetamide.

Liver injury was induced by one subcutaneous administration of thioacetamide (200 mg/kg b.wt.) and studied 24 and 48 hrs later. Levels of aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) increased after 24 and 48 hrs. The lysosomal enzymes beta-hexosaminidase (beta-NAG) and beta-glucuronidase (beta-GLU) increased significantly after 24 hrs, while the level of beta-GLU returned to normal after 48 hrs, but the activity of beta-NAG remained significantly high even after 48 hrs. Histopathological examination showed necrotic hepatocytes around the central vein with infiltration of macrophages, neutrophils and eosinophils. The plasma zinc level decreased after 24 hrs and returned to normal after 48 hrs. Liver zinc content increased simultaneously at 24 hrs, returning to normal after 48 hrs. No alterations of plasma copper were observed after 24 and 48 hrs. Copper content of the liver increased significantly after 24 and 48 hrs. The present study thus shows that one dose of thioacetamide results in profound liver injury and supplementation of zinc prior to and simultaneously with thioacetamide normalized plasma zinc, increased liver zinc content and reduced the increase of beta-NAG, but did not influence the histological changes.