Experimental comparison of meshes for rectal prolapse surgery.

AIM: The aim of this experimental study is to investigate the foreign body tissue created by the meshes that are used for rectopexy. METHOD: Sixty rats were divided equally into 5 groups. Four mesh types (Surgipro, Ivalon, Gore-Tex and Vypro) were implanted into the retroperitoneal area except for the sham group. After a 5-week follow-up period, all animals were sacrificed. Specimens were evaluated macroscopically by using scoring systems and biochemically by determining tissue hydroxyproline and nitric oxide levels. RESULTS: The most evident foreign body reaction was observed in the Ivalon group, which showed higher 'macroscopic adhesion' scores (p < 0.005), although there were no significant differences in tissue hydroxyproline and nitric oxide levels between the groups (p > 0.05). CONCLUSION: In rectal prolapse surgery, selecting the ideal mesh type is unclear, depending on evidence-based results. In the present study, we could not prove which mesh was definitely superior to the other, macroscopically, histologically and biochemically. The findings of this experimental rat model suggest that implantation of all 4 types of meshes are suitable for posterior rectopexy.

The urinary excretion of glycosaminoglycans and heparan sulphate in lupus nephritis.

Renal involvement in systemic lupus erythematosus (SLE) affects the disease outcome. In order to advance the diagnosis and the initiation of therapy, non-invasive diagnostic techniques are required. In this study, urinary glycosaminoglycans (GAG) and heparan sulphate (HS) were measured in 26 patients with biopsy-proven lupus nephritis and compared to 16 healthy controls. Uronic acid as a representative of GAGs in urine was determined spectrophotometrically with the meta-hydroxydiphenyl, following acid treatment. HS was determined as hexosamine by the method of Smith and Gilkerson. The median values of GAG (3.99 mg/g crea./day) and HS (2.41 mg/g crea./day) in patients were significantly ( P = 0.001) higher than in the control group (1.98 and 0.87, respectively). There was a positive correlation between GAG and HS values ( P = 0.000, r = 0.924) in SLE patients. There were no differences in HS excretion, microalbuminuria and SLE-DAI scores between different classes of lupus nephritis. However, GAG values in class 3 nephritis were significantly ( P = 0.033) higher than from both class 2 and class 4 lupus nephritis. There were no differences in all the measured parameters between normoalbuminuric, microalbuminuric and macroproteinuric patients. Furthermore, there were no correlations between GAG, HS excretions and SLE-DAI scores or microalbuminuria. These results suggest that urinary GAG and HS may serve as useful, independent and non-invasive markers of lupus nephritis.

Effects of strain, maternal age and sex on morphological characteristics and composition of tibial bone in broilers.

1. This study was to determine the effects of strain, age of the maternal flock and sex on morphological characteristics and composition of tibial bone of broilers from hatch to 48 d of age. 2. A total of 600 chicks was obtained from 2 strains of broiler breeder flocks (150/chicks/strain/maternal age). Maternal flock age was classified as young (32 to 35 weeks of age) or old (56 to 58 weeks of age). Birds were reared under standard feeding and lighting regimes. 3. On day 1, 16, 32 and 48, twelve birds were selected at random from each maternal group, strain and sex and killed. The wet bone weight and volume were measured. Morphological characteristics of tibia were determined using radiography. Bone breaking strength was tested. Tibia dry matter, ash content, mineral density and collagen level were determined. 4. A quadratic increase occurred with increase in age of broilers for all variables, except proximal width, medial cortex thickness and distal condyle width which increased in a linear manner. 5. Maternal age had a significant effect only on the variably measured at the time of hatch. On day of hatch bone weight, ash content and bone volume were affected by maternal age, but the extent of this also depended on the strain. 6. The differences observed between strains for bone anatomy and bone mineralisation during the rapid growth period of 16 d were not significant at later ages, with the exception of bone volume. Differences between sexes were evident from 16 to 49 d of age with females having lower values.

The effects of melatonin on the antioxidant systems in experimental spinal injury.

Melatonin has been recently shown by various in-vivo and in-vitro studies to exert potent neutralising effects on hydroxyl radicals, stimulate glutathione peroxidase (GSH-Px) activity, and protect catalase (CAT) from the destructive activity of hydroxyl radicals in neural tissue. We aimed to investigate the possible effects of pharmacological dose of melatonin on some of the antioxidant defence systems in an in-vivo study of experimental spinal injury. Seven groups of adult male Sprague Dawley rats were used in the following scheme: Group I: Naive (n = 6), Group II: Lesion (n = 8), Group III: Melatonin (n = 5), Group IV: Melatonin + Lesion (n = 8), Group V: Placebo + Lesion (n = 5), Group VI: Sham operation (n = 5), and Group VII: Placebo (n = 5). Experimental spinal injury was induced at level T7-T8 by 5 sec compression of the total cord with an aneurysm clip on anaesthetised and laminectomized animals. The total 10 mg/kg dose of melatonin (Sigma) dissolved in alcohol-water was administered i.p. four times in 2.5 mg/kg doses, at 20 min pre-, at the time of and at 1 h and 2h post-compression. At 24 +/- 2h post-injury, the rats were euthanized and the lesioned segments of cord were dissected and homogenised with special care taken to distribute equal amount of injured tissue in each sample for analysis of reduced glutathione (GSH), oxidised glutathione (GSSG), superoxide dismutase (SOD), and CAT activity. Compression injury decreased GSH/GSSG ratio significantly (p < .0001). Melatonin, by itself, significantly decreased GSSG content (p < .05) and increased CAT activity (p < .05) in the naïve rats. Melatonin treatment decreased GSSG activity, thus elevating GSH/GSSG ratio, and also increased SOD and CAT activity without reaching statistical significance in the lesioned animals. In conclusion, pharmacological dose of systemically applied melatonin seemed to support some features of the antioxidant defence systems in our hands.

The effects of chronic hepatitis C and B virus infections on liver reduced and oxidized glutathione concentrations.

The aim of this study was to evaluate the effects of hepatitis B and C virus infections on liver glutathione status. Reduced and oxidized glutathione levels were determined in liver biopsy specimens obtained from patients with chronic liver disease including chronic active hepatitis and cirrhosis. In patients with hepatitis B virus infections, GSH and GSH/GSSG levels were significantly low compared with those in controls (P<0.01). There was a significant negative correlation between histological activity indices (HAI) and hepatic GSSG levels only in patients with chronic HCV infection (P<0.01; r=-0.895). In addition to this, we also found a positive correlation between indices (HAI) and GSH/GSSG of the same group (r=0.915; P<0.05). These observations suggest that HBV and HCV infections have different effects on liver glutathione status based on diverse mechanisms.

Effects of trimetazidine on oxidant/antioxidant status in trinitrobenzenesulfonic acid-induced chronic colitis.

Trimetazidine (TMZ), an anti-ischemic agent with proposed antioxidant properties, was used in a chronic colitis model in order to evaluate its effectiveness as a therapeutic agent in chronic colitis. Treatment of male Swiss Albino rats with ethanol (50%) and trinitrobenzenesulfonic acid (TNBS) (30 mg/kg) produced colitis as evidenced by histopathologic damage and inflammatory alterations, lipid peroxidation [increased malondialdehyde (MDA) levels], and enhanced neutrophil infiltration [increased myeloperoxidase (MPO) activity] without marked change in glutathione status. Administration of TMZ (5 mg/kg) to TNBS-treated rats failed to affect the TNBS-induced changes in histopathology and MPO activities. Unexpectedly, intrarectal (i.r.) administration of TMZ significantly elevated colonic MDA levels to a greater extent than TNBS alone. Intraperitoneal (i.p.) TMZ treatment seemed to increase total glutathione (tGSH), GSH, and GSH/GSSG values. In conclusion, our results demonstrated that (a) i.r. administration of ethanol and TNBS is an effective way of inducing a chronic colitis model, (b) inflammation and lipid peroxidation augment tissue damage in the chronic colitis model, (c) i.p. TMZ treatment significantly inhibits MDA production in the chronic colitis model, (d) TMZ treatment is more effective via the i.p. compared to i.r. route, and (e) TMZ seems to show its antioxidant effect via preserving the tissue's GSH/GSSG ratios.

Cytoprotective effects of trimetazidine in carmustine cholestasis.

Carmustine [1 ,3-bis(2-chloroethyl)-1-nitrosurea (BCNU)] is an antitumour agent, however, its usefulness has been limited by a side effect; which involves pericholangitis and intrahepatic cholestasis. The primary effects of cholestasis is well known; bile flow retention, intracellular Ca++ accumulation and acidosis although it may lead to hepatotoxicity by dose-dependent manner. Recent studies provide evidence that lipoperoxidation (LPO) and alterations in the antioxidant system may significantly contribute to BCNU induced hepatotoxicity. Trimetazidine, (1-[2,3,4-Trimethoxy-benzyl] piperazine HCl; TMZ) introduced as an antianginal compound, is found to exhibit various cytoprotective features by preserving cellular ATP levels, limiting intracellular acidosis and inorganic phosphate as well as Na+ and Ca++ accumulation in ischemic cardiac injury. No study was undertaken to investigate the cytoprotective role of TMZ in cholestatic injury till today; therefore we initiated this study to investigate if its cytoprotective features also exhibit in the liver and to characterize further the cholestatic response to BCNU administration. Male rats were randomly seperated to control (CONT) (n = 15), BCNU administered (BCNU) (n = 16) and BCNU+TMZ administered (BCNU+TMZ) (n = 12) groups. The control rats received a single dosage of 2 ml/kg of corn oil (i.p.) while the BCNU group received a single dosage of BCNU (20 mg/kg, i.p.) in corn oil. In the BCNU + TMZ group 2,5 mg/kg/day (i.p.) of TMZ was administered for three days. This group also received BCNU (20 mg/kg, i.p.) in corn oil, 12 hours after the initial dose of TMZ. The cholestatic effect of BCNU was monitored by stasis markers such as ALP, GGT and total bilirubin levels. Hepatic TBARS analysis was determined with the modified method of OKHAWA et al. based on the reaction of lipid peroxides with thiobarbituric acid. Oxidized (GSSG) and reduced (GSH) glutathione levels were measured by the modified enzymatic recycling method of TEARE et al. Statistical tests were performed using Kruskal Wallis one-way Anova test and posthoc analysis by Newman-Keuls test. The BCNU group and the BCNU + TMZ group showed significant increases (p = 0.029) in hepatic TBARS levels compared to the CONT group; however the difference between the BCNU and BCNU + TMZ groups in regard to TBARS was not significant. BCNU and BCNU + TMZ groups manifested a significant decrease (p = 0.0005) in GSH levels as compared to controls. GSH/GSSG ratios in the BCNU and BCNU + TMZ group also manifested a significant decrease (p = 0.0013) as compared to the CONT group. TMZ administration caused a significant increase in total GSH levels (p = 0.0026) in BCNU + TMZ group when compared to the BCNU group. Our results support the hypothesis that BCNU induced cholestasis partly involves LPO revealed by the distinct increase in the content of TBARS in the liver after BCNU administration. BCNU is a potent inhibitor of GSSG reductase altering the preservation of the thiol redox balance in the system. As a result, supranormal concentrations of intracellular GSSG would accumulate in the hepatocyte and the extrusion of this oxidized compound would require active transport leading to ATP hydrolysis. This would deplete the energy stores of the cell which would accelerate further the possible prooxidant status. Although administration of TMZ did not provoke any significant alterations in LPO, it preserved the total GSH levels of the cell probably by improving the energy status of the cell by protection of ATP-producing processes at the mitochondrial level and provision of the necessary substrates for GSH synthesis. This protective role in the antioxidant system normalizes the altered GSH levels by BCNU and hence proposes TMZ to be a promising agent in the cholestatic injury.

Paraoxonase and acetylcholinesterase activities in humans exposed to organophosphorous compounds.

Different kinds of organophosphorous compounds (OP) are used as pesticides in Turkish agriculture. Suicidal, accidental, or occupational exposure may occur in developing countries. OP inhibit acetylcholinesterase (AChE) activities; on the other hand, serum paraoxonase (PON1) hydrolyzes the toxic metabolites of a variety of OP. In recent years, some studies have shown that PON1 activity is an important marker in individuals who are exposed to OP. Both serum cholinesterase and PON1 activities were measured spectrophotometrically from 18 male agricultural workers who were chronically exposed to azinphos methyl, chlorpyriphos, or malathion and other pesticides during cereal spraying, transportation, and storage. The individuals were classified according to PON1 phenotypes using the antimode 60% stimulation method to determine the dividing point between non-salt-stimulated, A type (homozygotes for the low-activity allele), and salt-stimulated AB (heterozygotes) and B types (homozygotes for the high-activity allele). A positive correlation was found between AChE activities and percent of PON1 stimulation. The individuals with phenotype A had the lowest enzyme activities. This study suggests that individuals with phenotype A might be more sensitive to OP-induced toxicity.

The effect of interferon therapy on erythrocyte membrane Na+,K+ ATP activity in patients with chronic hepatitis B and C virus infections.

In order to evaluate the effect of alpha interferon on erythrocyte membrane Na+,K+ ATPase (EC 3.6.1.37) activity, 10 patients with chronic hepatitis B virus (HBV) infection and 8 patients with chronic hepatitis C virus (HCV) infection were investigated. Erythrocyte membrane Na+,K+ ATPase activity was determined in controls and in patients with HBV and HCV infection. Na+,K+ ATPase activity was significantly less in untreated patients with (HBV) infection (n = 20; 0.134 +/- 0.073 mumol of phosphate produced per milligram of protein per hour) and (HCV) infection (n = 11; 0.144 +/- 0.049) when compared to the controls (n = 10; 0.219 +/- 0.055). Among these subjects patients were treated with interferon and following treatment, significant elevation of Na+,K+ ATPase activity was seen in patients with HCV (n = 8; 0.183 +/- 0.044; P = 0.049) and HBV (n = 10, 0.213 +/- 0.095, P = 0.0069) infections when compared with the pre-treatment values (n = 8; 0.152 +/- 0.050) and (n = 10, 0.131 +/- 0.083), respectively. Normalization of serum alanin amino transferase levels (ALT) at treatment cessation was seen in 8 of 10 (%80) HBV infected patients of whom 2 of 8 (%25) had sustained ALT responses within three months after the end of treatment. In HCV infected patients 1 of 8 (%12.5) had sustained response following treatment. At the end of treatment, although Na+,K+ ATPase was restored in both of the patients groups, relative changes in enzyme activity in relation to relative reduction in ALT levels as a response to IFN therapy were not correlated.

Erythrocyte membrane Na+,K+ ATP ase activity can be a marker of liver histopathology.

Erythrocyte membrane Na+,K+: Ca2+ ATP ase activities, cholesterol (CH) phospholipid (PL) composition and erythrocyte glutathione (GSH) contents were determined in controls, in patients with chronic active hepatitis and liver cirrhosis. NA+,K+ ATP ase activities were significantly (P < 0.0001) less in patients with chronic active hepatitis and liver cirrhosis (n = 8, 0.102 +/- 0.02 mumol P/mg protein/hour; n = 8, 0.081 +/- 0.02 mumol P/mg protein/hour) than in controls (n = 10, 0.219 +/- 0.05). Histopathological analysis of liver sections obtained from patients with chronic active hepatitis (n = 3) and liver cirrhosis (n = 2) correlated well with erythrocyte biochemical findings. There was a significant negative correlation between Na+,K+ ATP ase activity and portal fibrosis (P < 0.05, r = -8680). However, further experiments performed on larger study populations are needed to better elucidate this correlation. Therefore, NA+K+ ATP ase activity measurement can be reliable assessment of liver fibrosis.

The endogenous scavengers in cerulein-induced acute pancreatitis.

Studies in animal models suggest that oxygen radicals are important in the pathogenesis of acute pancreatitis. Cerulein, a decapeptide isolated from the skin of the frog, Hyla caerula, is closely related to the C-terminus of cholecystokinin and it is a potent stimulant of pancreatic exocrine secretion. The aim of the present study was to measure the activity of endogenous scavengers, superoxide dismutase, catalase and glutathione levels in cerulein-induced acute pancreatitis in rats. We found that the plasma amylase and ribonuclease levels in the pancreatitis group were both significantly high (p < 0.01, p < 0.05, respectively) when compared with the control group. Although superoxide dismutase and glutathione levels of pancreatic tissue were decreased significantly (p < 0.01, p < 0.01 respectively), we observed a significant increase (p < 0.01) in catalase activity in the cerulein treated group compared to the control group. Therefore, we concluded that the profound alteration of the activities of endogenous scavengers (superoxide dismutase, catalase) and glutathione depletion occurring after cerulein-induced pancreatitis seemed to be important in tissue injury and may provide the basis for successful therapy of the disease.

Storage of rat liver for plasma membrane isolation.

We described a procedure for the preservation of rat liver which makes possible the isolation of plasma membranes after 10 days storage at -70 degrees C. The yield of plasma membranes obtained from the liver tissue kept at -70 degrees C for 10 days (3.43 +/- 0.08 mg protein/10 g wet liver) was not different statistically (P > 0.05) from the yield of freshly obtained plasma membranes (3.32 +/- 0.05 mg protein/10 g wet liver). However, a significantly low yield (2.65 +/- 0.08; P < 0.01) was obtained from 90 days stored rat liver when compared with the immediate isolation. Plasma membrane Na+, K+ ATPase and 5'nucleotidase activities of the stored liver for 10 days were not different statistically (P > 0.05) from the enzyme activities of the freshly isolated membrane fractions. In contrast there was a significant decrease (p < 0.0001) in the activities of both plasma membrane Na+, K+ ATPase and 5'nucleotidase activities of 90 days stored rat liver at -70 degrees C when compared with immediate isolation. Considering the electron microscopic findings; we observed that the preservation of the integrity of the plasma membrane fractions obtained from fresh and frozen livers for 10 and 90 days seemed to be parallel to the biochemical results. Therefore we suggest that, storage of rat liver tissue for 10 days make feasible to maintain the experimental design and give convenience for obtaining intact plasma membrane fractions.

Ethanol induced oxidative stress and membrane injury in rat erythrocytes.

The aim of this study was to observe membrane injury and to investigate the mechanism of antioxidant defence systems against acute ethanol toxicity. Erythrocyte superoxide dismutase and Na+, K(+)-ATPase activities were significantly decreased and catalase levels were significantly increased one hour after ethanol intoxication of male swiss albino rats. These data demonstrated that superoxide dismutase and catalase are susceptible to lipid peroxidation and that these enzymes protect tissues from free radicals. The possible mechanism involved in Na+, K(+)-ATPase and Ca(2+)-ATPase inhibition are discussed in relation to the development of ethanol toxicity and the role of lipid peroxidative processes.

Erythrocyte Na+,K(+)-ATPase activity does not predict therapeutic response to calcium antagonists in essential hypertension.

We investigated whether pre- and posttreatment analysis of erythrocyte membrane Na+,K(+)-ATPase (EC 3.6.1.37) activity would be a useful marker for screening hypertensive patients to determine who might benefit from treatment with calcium antagonists. Erythrocyte Na+,K(+)-ATPase activity and sodium and potassium (ENa, EK) contents were determined in controls and in patients with untreated essential hypertension before and after 4 weeks of treatment with nitrendipine. Na+,K(+)-ATPase activity was significantly (P < 0.0001) less in untreated hypertensive patients (n = 15; 104.60 +/- 29.37 nmol of phosphate produced per milligram of protein per hour) than in controls (n = 15, 171.87 +/- 34.42). After 4 weeks of nitrendipine treatment Na+,K(+)-ATPase activity was greater than in the pretreatment group: 158.13 +/- 26.80 (P < 0.001). Pretreatment ENa contents (22.34 +/- 4.77 mmol/L) were significantly (P < 0.0001) higher than in the normotensive group (13.14 +/- 3.32 mmol/L), but there was no significant difference between the controls and the posttreatment group (14.84 +/- 3.49 mmol/L). The control and pretreatment groups showed negative correlations between enzyme activity and systolic/diastolic blood pressure (P < 0.0001). The control and the posttreatment groups showed an inverse correlation between enzyme activity and ENa contents: r = -0.608 (P < 0.05) and r = -0.724 (P < 0.001), respectively. Although Na+,K(+)-ATPase is restored in hypertensive patients receiving nitrendipine treatment, relative changes in enzyme activity in relation to relative reduction in blood pressure response to treatment were not correlated.