OPN gene polymorphism (Ala250) and lower serum OPN levels are associated with urolithiasis.

Osteopontin (OPN) is one of the urinary proteins with an important role in stone formation. Recently, OPN Ala250 (rs1126616) polymorphism and other single nucleotide polymorphisms (SNPs) have been studied to define their role in urolithiasis. This study was conducted to examine the impact of OPN Ala250 polymorphism on the risk of stone formation and their association with serum OPN levels. OPN Ala250 polymorphism was investigated in 127 urolithiasis patients and 92 healthy controls. Stones were analyzed for their chemical composition by using X-Ray diffraction method. Genomic DNA was isolated from peripheral blood leucocytes. The study groups were genotyped by PCR-RFLP and serum OPN levels were measured by ELISA. There was a significant difference between urolithiasis patients and controls concerning genotype and allele frequencies of OPN Ala250 (p < 0.05). Separate analysis by BMI greater or less than 25 kg/m(2) showed that the presence of one mutant T-allele was more frequent in patients with higher BMI than patients with BMI less than 25 kg/m(2) (p < 0.05). Serum OPN concentrations were two-fold higher in the control group compared to urolithiasis patients (p < 0.05). But the mean serum levels did not show any significant difference between OPN Ala250 genotypes in both groups. Moreover, we found an association between higher BMI and stone formation. Our findings suggest that OPN Ala250 polymorphism is associated with the correlation between weight gain and urolithiasis. However, the correlation between urolithiasis and obesity needs to be further studied in larger cohorts.

Effects of Crataegus microphylla on vascular dysfunction in streptozotocin-induced diabetic rats.

Vascular dysfunction plays a key role in the pathogenesis of diabetic vascular disease. In this study, we aimed to investigate whether chronic in vivo treatment of Crataegus microphylla (CM) extract in diabetic rats induced with streptozotocin (STZ, intraperitoneal, 65 mg/kg) preserves vascular function and to evaluate whether the reduction of inducible nitric oxide synthase (iNOS), proinflammatory cytokines, and lipid peroxidation mediates its mechanisms of action. Starting at 4 weeks of diabetes, CM extract (100 mg/kg) was administrated to diabetic rats for 4 weeks. In aortic rings, relaxation to acetylcholine and vasoreactivity to noradrenaline were impaired, whereas aortic iNOS expression and plasma tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), total nitrite-nitrate, and malondialdehite levels were increased in diabetic rats compared with controls. Chronic CM treatment significantly corrected all the above abnormalities in diabetic rats. In comparison, pretreatment of the aorta of diabetic rats with N-[3(aminomethyl) benzyl]-acetamidine, dihydrochloride (10(-5) M), a selective inhibitor of iNOS, produced a similar recovery in vascular reactivity. These results suggest that chronic in vivo treatment of CM preserves endothelium-dependent relaxation and vascular contraction in STZ-induced diabetes, possibly by reducing iNOS expression in the aorta and by decreasing plasma levels of TNF-α and IL-6 and by preventing lipid peroxidation.

Darbepoetin α ameliorates neuronal damage in a rat model of acute ethanol intoxication.

OBJECTIVE: Acute ethanol intoxication has been shown to cause oxidative damage in many organ systems including the brain. Erythropoietin has antioxidant effects and prevents neuronal damage in the animal model of ischemic brain injury. In this study, we aimed to investigate the effects of darbepoetin alpha, an analog of erythropoietin with a longer half-life and higher in vivo activity, on ethanol-induced acute brain injury. METHODS: Forty-eight Wistar albino rats were allocated to four groups. The first group received ethanol treatment (E), the second group was treated with ethanol and darbepoetin (ED), the third group received only saline treatment (S), and the fourth group received both saline and darbepoetin treatment (SD). Plasma S100-ß and neuron-specific enolase (NSE) levels were measured. Histopathological evaluation of the brains was performed. RESULTS: The plasma S100-ß and NSE levels were significantly lower in group ED compared with group E. In group E, we have observed focal red-neuron formation at the granular layer of the dentate gyrus. We did not observe any histopathological changes in the other groups (ED, S, and SD). CONCLUSION: Our findings suggest that darbepoetin alpha has neuroprotective effect in acute ethanol intoxication, possibly through its antioxidant effect.

Effects of lycopene on oxidative stress and remnant liver histology after partial hepatectomy in rats.

BACKGROUND/AIMS: Partial hepatectomy is performed for the treatment of mass lesions in the liver. Lycopene, which is a carotenoid, is present in various physiologic processes. In this study, the effects of lycopene administration in partially hepatectomized rats were evaluated by assessing various oxidant/antioxidant parameters, remnant liver histology and plasma nitric oxide levels. METHODS: Thirty Wistar albino adult male rats were randomly divided into three equal groups as: Sham, Partial Hepatectomy and Lycopene-Administered + Partial Hepatectomy groups. Lycopene (4 mg/kg), which was dissolved in olive oil, was given to the rats per orally (via gavage tube) (0.1 ml) every day for 6 weeks before partial hepatectomy and for one week after partial hepatectomy. Tissue and blood samples were collected one week after partial hepatectomy. RESULTS: Plasma malondialdehyde (p<0.001) and nitric oxide (p<0.05) levels in the lycopene-administered + partial hepatectomy group were significantly higher than in the partial hepatectomy group. Intraerythrocytic glutathione (p<0.001), plasma (p<0.001) and liver tissue Cu-Zn (p<0.05) superoxide dismutase levels of the lycopene-administered + partial hepatectomy group were significantly lower than in the partial hepatectomy group. CONCLUSIONS: Lycopene administration could be harmful by increasing oxidative stress after partial hepatectomy.

Comparison of KRAS mutation tests in colorectal cancer patients.

The KRAS pathway and studies evaluating KRAS as a prognostic marker in colorectal cancer are discussed along with advances in KRAS gene mutation testing. Highly sensitive real-time polymerase chain reaction (PCR) methods were developed for this purpose. We examined the applicability of direct sequencing and two real-time PCR methods in the diagnosis of KRAS mutations. We used real-time PCR and direct sequencing-based methods to determine applicability of these KRAS mutation tests in 64 colorectal cancers. The two DNA samples found to be mutation positive by real-time PCR were analyzed again after diluting 100-fold. The results were the same. When we applied the same strategy for the direct sequencing, even a 10-fold dilution did not show the mutations. Therefore, we found that sequencing may not be informative when there are only a few mutant cells in the tumor. KRAS mutation screening on formalin-fixed, paraffin-embedded DNA is very efficient with real-time PCR methods in comparison to direct sequencing. The development and adoption of guidelines for KRAS mutation testing are crucial for success.

Effects of Ganoderma lucidum on obstructive jaundice-induced oxidative stress.

OBJECTIVE: Obstructive jaundice develops after occlusion of the common bile duct. Direct hyperbilirubinaemia, which occurs secondary to the condition, causes various life-threatening pathologies. Cytoprotective effects of Ganoderma lucidum (GL) have previously been shown. In this study, the effects of GL on oxidative stress and oxidant DNA damage in experimental obstructive jaundice were evaluated. METHODS: Sixty Wistar albino adult female rats were randomly divided into six weight-matched equal groups: sham group, bile duct ligated group (BDL); after sham operation 250 mg/kg/d of GL administered group, after sham operation 500 mg/kg/d of GL administered group, after bile duct ligation 250 mg/kg/d of GL administered (GL1BDL) group, and after bile duct ligation 500 mg/kg/d of GL administered (GL2BDL) group. GL polysaccharide was orally administered to the rats via gavage tube once a day for 14 days after bile duct ligation. RESULTS: The plasma malondialdehyde levels of the GL1BDL and GL2BDL groups were significantly lower than those of the BDL group (p < 0.01). The plasma 8-hydroxy-2'-deoxyguanosine levels of the GL1BDL and GL2BDL groups were significantly lower than those of the BDL group (p < 0.001). The liver tissue Cu-Zn superoxide dismutase level of the GL2BDL group was significantly higher than that of the BDL group (p < 0.05). CONCLUSION: GL protected against DNA and liver tissue damage by reducing oxidative stress in obstructive jaundice.

Gender-dependent oxidative variations in liver of aged rats.

A shift from redox regulation to oxidative damage is known to contribute organ dysfunction and aging-related disorders. Exposure to reactive oxygen species throughout the life-span increases the incidence of several liver diseases. A redox basis of the loss of antioxidant capacity of aged livers has not been fully elucidated in both genders. In the current study, we investigated the gender-dependent relations between protein carbonyl (PCO), a commonly used marker of protein oxidation and other protein oxidation parameters such as advanced oxidation protein products (AOPP) and total thiol (T-SH). Our study also covered other oxidative stress markers, such as malondialdehyde (MDA), lipid hydroperoxides (LHP), and glutathione (GSH) in liver tissue of the male and female aged rats. PCO and AOPP levels in old male and female rats were significantly higher than those in the young control groups (P < 0.001 and P < 0.01, respectively for male rats; P < 0.001 for both parameters in female rats). On the other hand, T-SH levels were not found to be different between young and old rat groups. Plasma MDA levels of old male and female rats were significantly higher compared to those of the young control groups (P < 0.01 and P < 0.001, respectively). LHP levels were only found out to be significantly higher in old female rats when compared to those in young male rats. GSH levels in old male and female rats were significantly lower than in the corresponding young control groups (P < 0.01 for male rats; P < 0.05 for female rats). Our results demonstrated greater susceptibility to hepatic oxidative damage in females than in males. This appears to contradict the general assumption that females are less susceptible to oxidative injury than males are.

The effects of eicosapentaenoic acid on the endothelium of the carotid artery of rabbits on a high-cholesterol diet.

The preventive and therapeutic effects of eicosapentaenoic acid (EPA) on diet-induced hyperlipidemia in rabbits have been investigated. Eighteen New Zealand rabbits were randomly divided into three groups of 6 subjects each; experimental group-I (EG-I) was administered a cholesterol rich diet, experimental group-II (EG-II) was treated with EPA (300 mg/kg/d) following a cholesterol-rich diet and the control group (CG) had a standard diet. Blood samples were collected at day 0 and at the 4th and 12th weeks of EG-II to obtain serum levels of total cholesterol (TC), high density lipid-cholesterol (HDL-C), low density lipid-cholesterol (LDL-C) and triglyceride (TG). From each group tissue samples were collected from the carotid artery for immunohistochemistry and electron microscopy. Our results showed that EPA could significantly lower (p<0.001) serum TC, LDL-C, HDL-C and TG levels with a reduction of 35%; 55%; 44% and 51%, respectively. Scanning and transmission electron microscopy results revealed that endothelial damage was more prominent in EG-I when compared to EG-II. The ruptured endothelial lining and damaged cellular surface was increased in EG-I when compared to EG-II. Ultrastructural observations showed that after EPA treatment, the degeneration and cellular surface damage on the endothelium were also decreased. These biochemical and ultrastructural results suggest that EPA is a potential drug which significantly lowers the serum lipid profile and partially repairs endothelial dysfunction due to hyperlipidemia.

Effect of vitamin C on oxidative liver injury due to isoniazid in rats.

BACKGROUND: The aim of the present study was to investigate the effect of different doses of vitamin C on oxidative liver injury due to isoniazid (INH) in rats. METHODS: Rats were divided into four subgroups, each containing 10 rats. Group 1 was the control group; group 2, INH 50 mg/kg per day; group 3, INH 50 mg/kg per day + low-dose vitamin C (100 mg/kg per day); group 4, INH 50 mg/kg per day + high-dose vitamin C (1000 mg/kg per day). INH and vitamin C were administered into their stomachs through an oral tube. After 21 days, measurements were made in both serum and homogenized liver tissues. The levels of glutathione (GSH), superoxide dismutase (SOD) and other biochemical variables were measured. Malondialdehyde (MDA), glutathione peroxidase (GSH-px) and vitamin C were measured using commercial kits. RESULTS: Aspartate amino transferase and alanine aminotransferase in group 2 were higher than those in groups 1, 3 and 4 (P < 0.008 for both). Serum and tissue levels of MDA in group 2 were higher than that in groups 1 and 3 (P < 0.008 for both). There was no difference in the SOD levels between the four groups (P= 0.095). Erythrocyte and tissue GSH in group 2 were higher than that in groups 1 and 3 (P < 0.008 for both). Interestingly, erythrocyte and tissue GSH in group 4 were lower than those in group 1 (P < 0.008 for both). Erythrocyte level of GSH-px in group 2 was higher than that in groups 1 and 3 (P < 0.008 for both). CONCLUSIONS: INH-induced liver injury is associated with oxidative stress, and co-administration of low-dose vitamin C may reduce this damage effectively in a rat model. The antioxidant effect of high-dose vitamin C does not seem more potent compared to the low dose.

Curcumin prevents shock-wave lithotripsy-induced renal injury through inhibition of nuclear factor kappa-B and inducible nitric oxide synthase activity in rats.

Shock wave lithotripsy (SWL) is commonly used for treatment of renal stones. Free oxygen radicals are involved in the pathophysiology of renal injury due to SWL. We investigated the protective effects of curcumin, which is an antioxidant and nuclear factor kappa-B (NF-kappaB) inhibitor, against renal injury. Forty-eight rats were included and divided into four groups: group 1, control; group 2, SWL (15 kW-1,500 shocks); group 3, SWL + curcumin (curcumin orally 75 mg/kg/day dissolved in 10% ethyl alcohol, 1 day before and 5 days after SWL); and group 4, SWL + vehicle (10% ethyl alcohol). The kidneys were removed on days 7 and 35 after SWL. A sample was fixed in formaldehyde solution. Renal tissues were examined for proximal tubular injury under light microscope. iNOS activity and active subunit of NF-kappaB, p65, were evaluated immunohistochemically using rat monoclonal antibodies interpreting results semiquantitatively. There were significant differences between SWL and control groups on days 7 and 35, considering histological changes under light microscope (P < 0.02). There was a significant decrease in necrosis and fibrosis in the curcumin group as compared to the SWL group. Expressions of iNOS and p65 on days 7 and 35 were at basal levels with immunohistochemical staining. These parameters had high levels in the SWL group (P < 0.02). No significant difference was present between the control and the curcumin groups (P > 0.02). Curcumin, decreasing expressions of iNOS and p65 and serum nitric oxide levels prevented interstitial, glomerular, tubular epithelial and endothelial cellular injuries. We suggest that curcumin, could be used, especially in high-risk patients, as a protective agent to prevent renal injury due to SWL.

Influence of Tribulus terrestris extract on lipid profile and endothelial structure in developing atherosclerotic lesions in the aorta of rabbits on a high-cholesterol diet.

The aim of this study was to investigate the pleotropic effects of an extract of a traditional herb, Tribulus terrestris (TT), on the lipid profile and vascular endothelium of the abdominal aorta in New Zealand rabbits fed a cholesterol-rich diet. Eighteen rabbits were randomly divided into three groups (n=6 for each). One experimental group (EG-I) was given a cholesterol-rich diet, a second experimental group (EG-II) was treated with TT following a cholesterol-rich diet, and a control group (CG) was fed a standard diet. Blood samples were collected on day 0 and then at weeks 4 and 12 to determine total serum cholesterol (TC), high density lipid-cholesterol (HDL-C), low density lipid-cholesterol (LDL-C) and triglyceride (TG) levels. Tissues were collected from the abdominal aorta for immunohistochemistry and transmission and scanning electron microscopy. In EG-II, the serum lipid profile was significantly lower than that of EG-I at week 12 with a reduction of TC: 65%; LDL-C: 66%; HDL-C: 64%; TG: 55%. Ultrastructural analysis revealed that endothelial damage was more prominent in EG-I compared to EG-II. The ruptured endothelial linings and damaged cellular surfaces increased in EG-I compared to EG-II. Our data indicate that dietary intake of TT can significantly lower serum lipid profiles, decrease endothelial cellular surface damage and rupture and may partially repair the endothelial dysfunction resulting from hyperlipidemia.

The role of amifostine on late normal tissue damage induced by pelvic radiotherapy with concomitant gemcitabine: an in vivo study.

In this in vivo study, we aimed to assess the radioprotective effect of amifostine on late normal tissue damage induced by gemcitabine concomitant with pelvic radiotherapy by histopathological and quantitative methods. Fifty-six male Wistar albino rats were randomly divided into seven experimental groups as follows: (I) gemcitabine, (II) radiation + gemcitabine, (III) radiation + gemcitabine + amifostine, (IV) radiation + amifostine, (V) sham radiation, (VI) amifostine, (VII) radiation. Irradiation was given to pelvic region with a dose of 25 Gy in 5 fractions. Amifostine was given for 30 min; gemcitabine was administered 24 h before the first fraction of radiotherapy. All animals were killed at the end of 4th month. Pathological examination was performed and the tissue collagen content was measured in bladder and rectal tissues. Fifty-one animals that were alive at the end of the follow-up period were analyzed. Thirty-five animals (68.6%) revealed grades I-III late effect in histopathological examination. We observed grade III colitis in 1 animal (radiation + gemcitabine) and bladder fibrosis in 4 animals (radiation and radiation + gemcitabine groups). There was no significant difference between any groups for bladder cystitis and fibrosis by Kruskal-Wallis method. Colitis was seen significantly lower in the radiation + gemcitabine + amifostine group (P = 0.0005). The collagen contents in the bladder and rectum of radiation and radiation + gemcitabine groups were markedly increased as compared to the sham group. This effect was reversed in the groups which received amifostine in addition to radiation and radiation + gemcitabine groups, but this difference was not significant. This study demonstrated that amifostine may have a beneficial effect in limiting rectal colitis from the radiosensitizing effect of gemcitabine.

Protective effect of a potent antioxidant, pomegranate juice, in the kidney of rats with nephrolithiasis induced by ethylene glycol.

PURPOSE: We aimed to study the protective effects of pomegranate juice (PJ) on ethylene glycol (EG)-induced crystal deposition in renal tubules, renal toxicity, and inducible nitric oxide synthase (iNOS) and nuclear factor-kappaB activities in rat kidneys. MATERIALS AND METHODS: Fifty-six rats were divided into four equal groups: Control, EG, EG + 50 microL PJ/d (PJ50), and EG + 100 microL PJ/d (PJ100). Rats were sacrified on days 10 and 45. Tissue sections were evaluated under light and polarized microscopy for the presence and degree of crystal deposition and toxicity in the kidneys. Crude extracts of the cortex were used to determine reduced gluthatione (GSH), nitric oxide (NO), and malondialdehyde (MDA) levels. RESULTS: In the EG group, crystal depositions were more evident and mild crystalization was observed in proximal tubules on day 10; severe crystalization and granulovacuolar epithelial cell degeneration were observed on day 45. There was limited or no crystal formation in the EG + PJ-given groups. There were completely normal renal and tubular structures in the control group. There was no significant difference between the four groups in serum levels of sodium, potassium, blood urea nitrogen, and creatinine in any sampling time. Hyperoxaluria, a marked increase in MDA and NO levels, and decrease of GSH were observed in the EG-given groups compared with the others. There were marked iNOS and p65 expressions in only the EG-given rats compared with control and PJ groups, immunohistochemically. CONCLUSION: This experiment shows the protective effect of PJ in the EG-induced crystal depositions in renal tubules.

Pyrolidium dithiocarbamate prevents shockwave lithotripsy-induced renal injury through inhibition of nuclear factor-kappa B and inducible nitric oxide synthase activity in rats.

PURPOSE: Extracorporeal shockwave lithotripsy (SWL) is commonly used for treatment of renal stones. Free oxygen radicals are involved in the pathophysiology of renal injury due to SWL. We investigated the protective effect of pyrolidium dithiocarbamate (PDTC), an antioxidant and nuclear factor kappa-B (NFkappa-B) inhibitor, against renal injury. MATERIALS AND METHODS: Forty-eight rats were divided into three groups: group 1, controls; group 2, SWL (15 kW, 1500 pulses); and group 3, SWL + pyrolidium dithiocarbamate (PDTC) (100 mg/kg/day given intraperitoneally 1 day before and 5 days after SWL). The rats were sacrificed and their kidneys were removed on days 7 and 35 after SWL. Samples were fixed in formaldehyde solution, and renal tissues were examined for proximal tubular injury under light microscopy. iNOS activity and active subunit of NFkappa-B, p65, were evaluated immunohistochemically using rat monoclonal antibodies interpreting results semiquantitatively. RESULTS: There were significant differences between SWL and control groups on days 7 and 35, considering histological changes under light microscope (p < 0.02). There was significant decrease in necrosis and fibrosis in PDTC group compared to SWL group. Expression of inducible nitric oxide synthase (iNOS) and p65 on days 7 and 35 were at basal levels as seen with immunohistochemical staining. There were high concentrations of iNOS and p65 in the SWL group (P < 0.02). No significant difference in concentrations was seen between the control and the PDTC groups (P > 0.02). CONCLUSION: We found that curcumin decreased the expression of iNOS, p65, and serum nitric oxide levels, and helped prevent interstitial, glomerular, tubular epithelial, and endothelial cellular injury. We believe that PDTC could be used, particularly in high-risk patients, as a protective agent against renal injury due to SWL.

Rapid communication: protective effect of a nuclear factor kappaB inhibitor, pyrolidium dithiocarbamate, in the kidney of rats with nephrolithiasis induced by ethylene glycol.

PURPOSE: To study the protective effects of a selective nuclear factor kappa B (NF-kappaB) inhibitor, pyrolidium dithiocarbamate (PDTC), on ethylene glycol-induced crystal deposition in the renal tubules, renal toxicity, as well as inducible nitric oxide synthase (iNOS) and NF-kappaB activities in rat kidneys. MATERIALS AND METHODS: Rats were divided into three equal groups: control, ethylene glycol-treated (EG), and ethylene glycol + PDTC treated (EG+PDTC). Rats were sacrificed on day 7, 15, or 45, and tissue sections were evaluated under light and transmission electron microscopy for the presence and degree of crystal deposition and toxicity in the kidneys. The iNOS and NF-kappaB activity were evaluated immunohistochemically, with p65 being stained to define NF-kappaB activity. Crude extracts of the cortex were used to determine reduced glutathione (GSH), nitric oxide (NO), and malondialdehyde (MDA) concentrations. RESULTS: Crystal depositions were more evident in the proximal tubules on day 7 in the EG than in the other groups. Mild crystallization was observed on day 15, and severe crystallization and granulovacuolar epithelial-cell degeneration were observed on day 45. There was limited or no crystal formation in the EG+PDTC group and completely normal renal and tubular structures in the control group. Whereas ethylene glycol administration stimulated iNOS and NF-kappaB/p65 activity in renal tubules, PDTC inhibited it. Rats given only vehicle demonstrated no significant alterations. Hyperoxaluria, a marked increase in MDA and NO concentrations, and a decrease in GSH were observed in the EG group. CONCLUSION: This experiment has shown the role of transcription factors, NF-kappaB, and iNOS in ethylene glycol-induced crystal depositions in renal tubules.

Effects of atorvastatin therapy on hypercholesterolemic rabbits with respect to oxidative stress, nitric oxide pathway and homocysteine.

Hypercholesterolemia is characterized with changes in lipid profile, nitric oxide pathway and oxidative stress markers. This study is designed to evaluate the effects of hypercholesterolemic diet and atorvastatin therapy on oxidative stress, lipid peroxide and thiobarbituric acid reactive substances (TBARS), NO pathway markers, nitric oxide(NO) and asymmetric dimethylarginine (ADMA), homocysteine, and paraoxonase activity (PON1) in rabbits. Twenty rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into 2 groups on the fourth week of the hypercholesterolemic diet. First group was fed with high-cholesterol diet alone, whereas the second group with the same cholesterol diet plus atorvastatin (0.3 mg/kg/day) for 4 weeks. High-cholesterol diet increased total cholesterol, low density lipoprotein (LDL-C), high density lipoprotein (HDL-C), ADMA, TBARS and lipid peroxide levels and reduced PON1 activity and NO levels in rabbits. Four weeks of atorvastatin therapy significantly increased HDL-C, PON1 activity and reduced LDL-C, TBARS and lipid peroxide concentrations. Atorvastatin therapy is beneficial in decreasing oxidative stress related with hypercholesterolemia, mainly affecting lipid profile and PON1 activity.

Atorvastatin has cardiac safety at intensive cholesterol-reducing protocols for long term, yet its cancer-treatment doses with chemotherapy may cause cardiomyopathy even under coenzyme-Q10 protection.

Statins provide strong clinical benefits via reducing stroke deaths, and they are also considered for tumor reduction and chemo-sensitization. High dose atorvastatin in adults (80 mg daily, approx. 1 mg/kg) is proven to afford greater protection against cardiac deaths than does a standard lipid-lowering dose in coronary syndrome. For cancer trials, mega doses up to 30 mg/kg have been used for short term treatments but neither a high nor a mega-dose of atorvastatin has been tested for long term cardiac safety. This may be of special concern, since some animal studies showed deleterious effects of statins on cardiac tissue, which may be related with coenzymeQ (CoQ) depletion. We performed an electron microscopic analysis of rat hearts after low, high-or mega-dose atorvastatin therapy and with or without MNU (methyl-nitrosourea)-stress. MNU + daily high dose atorvastatin treatment for 13 months did not produce severe cardiac toxicity with CoQ. However, at mega doses (30 mg/kg) and with MNU, mitochondrial damage and myofibrillary disintegration was obvious. Strong proliferation of mitochondria under high dose atorvastatin therapy with CoQ may explain the lack of cardiotoxicity; and this finding seems to parallel recent data that statins induce HNF-4 and PPAR-alpha, both responsible for mitochondria-proliferation. Employment of statins for tumor chemo-sensitization at high-dosage and for long term treatments may require strategies to direct the mevalonate-entry differentially into cardiac and tumor cells and to develop a protocol analogous to folic acid salvage of methotrexate toxicity.

The Relationship Between Lipid Peroxidation and LDL Desialylation in Experimental Atherosclerosis.

ABSTRACT High serum total cholesterol concentration has been strongly connected with atherosclerosis in numerous studies. Being the main carrier of cholesterol in blood, low-density lipoprotein (LDL) is also the principal lipoprotein causing atherosclerosis. Sialic acids are a family of amino sugars that are commonly found as terminal oligosaccharide residues on glycoproteins and are sialylated on their apolipoprotein and glycolipid constituents. In several studies, it was demonstrated that LDL has a 2.5- to 5-fold lower content of sialic acid in patients with coronary artery disease compared with healthy subjects. The role of oxidatively modified LDL in the pathogenesis has been well documented. These studies have focused on modifications in the lipid and protein parts of LDL. But recently, desialylated LDL and its relation with the oxidation mechanisms have received attention in the pathogenesis of atherosclerosis and coronary artery disease (CAD). From these points, we have performed atheroma plaques in an experimental atherosclerosis model with rabbits and examined the LDL and plasma sialic acid and thiobarbituric acid reactive substance (TBARS) levels in the same model. We also have determined serum sialidase enzyme activities relevant with these parameters. LDL sialic acid levels were significantly decreased in the progression of the atherosclerosis (by the 30th, 60th, and 90th days). LDL and plasma TBARS levels and plasma sialidase enzyme activities were significantly elevated by the same time periods. In conclusion, serum sialidase enzyme may play an important role in the desialylation mechanism, and reactive oxygen substance (ROS) may affect this reaction.

Suramin increased telomerase activity in the c6 glioma/wistar experimental brain tumor model.

Glioblastoma multiforme (GBM) is the most treatment-resistant glioma variant. Significant roles for telomerase in etiology, recurrence and drug resistance of GBM have been highlighted. Suramin (Bayer, Leverkusen, Germany) is an antineoplastic agent that affects many cellular mechanisms including growth factor, purinergic receptor, cytokine and key cellular enzymes signaling. The aim of this study was to investigate whether suramin, 40 mg/kg, i.p., inhibits telomerase activity in a subcutaneous C6 glioma/Wistar experimental brain tumor model using PCR based telomeric repeat amplification assay. In comparison to the control group, suramin increased tumor volume and telomerase activity. We also used transmission electron microscopy to evaluate the alterations of cell morphology. Apoptosis was seen markedly in electron micrographs of the control group and anti-apoptotic activity of telomerase was verified in the electron micrographs of suramin-applied group. The in vitro inhibitory effects of suramin on telomerase activity in several cell lines except for brain tumors have been reported. Contrary to in vitro reports, our results were the first to demonstrate that suramin increased telomerase activity in a C6 glioma/Wistar experimental brain tumor. Large numbers of drugs exhibited apparent hormetic effects on cultured cancer cells and in vivo cancer growth. Several drug examples for their hormetic effects in vivo were listed as resveratrol, suramin, and tamoxifen. The action of suramin in the present study could be evaluated as one of the hormetic examples of suramin in vivo.

Selective nuclear factor kappa-B inhibitors, pyrolidium dithiocarbamate and sulfasalazine, prevent the nephrotoxicity induced by gentamicin.

OBJECTIVE: To investigate the effect of selective nuclear factor kappa-B (NFkappa-B) inhibitors, pyrolidium dithiocarbamate (PD) and sulfasalazine (SZ) on renal tubular necrosis and inducible nitric oxide synthase (iNOS) and NFkappa-B expression induced by gentamicin in rats. MATERIALS AND METHODS: In all, 48 adult male Sprague-Dawley rats were divided into six equal groups; group 1, control; group 2, injected with gentamicin for 10 days (100 mg/kg/day, intraperitoneal, i.p.); group 3, injected with gentamicin plus PD (100 mg/kg/day, i.p.); group 4, injected with gentamicin plus SZ (75 mg/kg/day, i.p.); group 5, injected with gentamicin plus distilled water (vehicle for PD); and group 6, injected with gentamicin plus ammonium hydroxide (75 mg/day, 1 m, vehicle for SZ) for 10 days. At 24 h after the last injection, rats were killed and the renal cortex separated from the medulla. A small sample was fixed in formaldehyde solution for histological and immunohistochemical examination. Blood samples were also taken to assess the serum levels of urea, creatinine, Na(+), K(+) and gamma-glutamyl transpeptidase (GT). Crude extracts of the cortex were used to determine reduced glutathione (GSH-Px), NO and malondialdehyde (MDA). Immunohistochemically, iNOS and the active subunit of NFkappaB, P65, were evaluated using mouse monoclonal antibodies. RESULTS: On haematoxylin and eosin staining, compared with the controls rats, gentamicin caused widespread tubular necrosis (grade 3 and 4) but in group 3 and 4 there was a marked reduction in the extent of tubular damage. Immunohistochemically there was more marked staining for iNOS and P65 expression in rats given gentamicin than in the control and group 3 and 4 (P < 0.001). In groups 3 and 4 iNOS and P65 expression were significantly less than in rats given only gentamicin. There was no significant difference in serum levels of Na(+), K(+), blood urea nitrogen and creatinine. Compared with control rats, gentamicin caused hyperproteinuria, a marked increase in levels of serum gamma-GT, MDA and NO, and a decrease in GSH-Px (P < 0.001). CONCLUSION: These results indicate that gentamicin induces iNOS expression through activation of NFkappa-B (P65). It is possible to prevent gentamicin-induced nephrotoxicity using selective NFkappa-B inhibitors.