High cholesterol diet leads to oxidant load and peroxidation in the rabbit kidney tissue.

OBJECTIVES: The aim of this study was to investigate possible effects of high cholesterol diet on oxidant/antioxidant status in rabbit kidney tissues. BACKGROUND: Although a number of experimental animal models have suggested that hyperlipidemia is associated with progressive kidney failure data remain sparse on the role of dietary cholesterol intake on kidney disease. METHODS: Twelve male New Zealand albino rabbits were randomly divided into two groups (control and cholesterol). Both groups were fed on a standard laboratory diet. Animals in the cholesterol group additionally received cholesterol (1 g/kg/day), orally. The study period was 12 weeks. Activities of catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), nitric oxide synthase (NOS), xanthine oxidase (XO), paraoxonase (PON), adenosine deaminase (ADA) enzymes and levels of malondialdehyde (MDA) and nitric oxide (NO) were measured in kidney tissue samples. Histological examination of the kidney tissue samples was also done. RESULTS: SOD, GSH-Px and XO enzyme activities were found to be decreased and NOS and PON activities increased significantly in cholesterol group compared to controls. As an indication of oxidation, MDA levels were found to be increased in cholesterol group. Histological examination revealed some derangements in the kidney tissue. CONCLUSION: High cholesterol diet creates oxidant load and causes peroxidation, which in turn, leads derangements in the rabbit kidney tissue (Tab. 2, Fig. 2, Ref. 69).

Effects of aqueous soybean, mistletoe and red clover extracts on activities of adenosine deaminase and xanthine oxidase enzyme.

Soybean (Glycine max), mistletoe (Viscum album) and red clover (Trifolium pratence) have been argued to have anti-cancer effects. In the present study it was aimed to investigate possible effects of these plant extracts on the activities of DNA turn-over enzymes, namely adenosine deaminase (ADA) and xanthine oxidase (XO) in cancerous and non-cancerous gastric and colon tissues. For this aim, 6 cancerous and 6 non-cancerous adjacent human gastric tissues, and 7 cancerous and 7 non-cancerous adjacent colon tissues were obtained by surgical operations. Our results suggest that aqueous soybean, mistletoe and red clover extracts may exhibit anti-tumoral activity by depleting hypoxanthine concentration in the cancer cells through XO activation, which may lead to lowered salvage pathway activity necessary for the cancer cells to proliferate in the cancerous colon tissue. Some foods like soybean, mistletoe and red clover may provide nutritional support to medical cancer therapy through inhibiting and/or activating key enzymes in cancer metabolism (Tab. 4, Ref. 33).

Nitric oxide metabolism in cancerous and non-cancerous oral gingivomucosal tissues: possible implications of nitric oxide in cancer process.

PURPOSE: Nitric oxide (NO) is a molecule that plays various roles in the body tissues. NO plays important roles in vasodilatation, platelet aggregation, cytokine stimulation, neurotransmission, immune function, etc. NO also exerts dual functions as an oxidant and antioxidant substance depending on its concentrations and environmental conditions. In this study, we aimed to examine possible correlation between NO levels and NO synthase (NOS) activity in the patients with oral cancer. MATERIALS AND METHODS: The study included 19 tissues from human subjects (11 malign and eight benign lesions). RESULTS: NO level and NOS activity were found decreased in the malign lesions compared with those of the benign ones. CONCLUSIONS: In conclusion, two suggestions can be made; first, decreased NO synthesis may be an attempt to suppress angiogenesis, which is known to provide more essential nutrients to malign lesions and/or second, malign lesions may suppress NO production to be capable of creating more rapid proliferation as it has been known that NO is also a powerful free radical inducing apoptosis.

Adenosine deaminase and 5'-nucleotidase activities in saliva from patients with oral and laryngeal cancer.

OBJECTIVE: The aim of this study was to evaluate saliva's activities of adenosine deaminase (ADA) and 5'-nucleotidase (5'-NT) enzymes and their utility as diagnostic and therapeutic markers in oral and laryngeal cancer. MATERIALS AND METHODS: Pre- and post-operative saliva's activities of ADA and 5'-NT enzymes were measured in patients with squamous cell oral (n = 10) and laryngeal cancer (n = 17) and compared with control saliva samples (n = 19). RESULTS: The ADA was found to be lower in saliva of the patients with oral cancer compared with the laryngeal cancer and controls. However, no significant differences were found between pre- and post-operative values for both enzymes in the patient groups. We also could not find statistically significant differences between saliva's activities of 5'-NT in patients and control subjects. CONCLUSIONS: Low activity of ADA observed in saliva of the patients with oral cancer has been suggested as a compensatory mechanism against rapid purine and DNA metabolism in cancer cells. The current study does not support the hypothesis that saliva's activities of these enzymes may be used as additional diagnostic and prognostic cancer markers.

A potential role for nitric oxide pathway in tuberculous pleural effusion.

SETTING: Tuberculous pleural effusion leads to an immune response involving mainly immune and mesothelial cells. Nitric oxide (NO) produced by these cells may have antimycobacterial effects against Mycobacterium tuberculosis. OBJECTIVE: To investigate the possible role of NO in connection with the arginase enzyme, which controls the synthesis of NO through arginine depletion. DESIGN: Pleural fluid samples from 20 patients with tuberculous pleural effusion were used for arginase activity and NO level determination. Results were compared with those from 12 lung cancer, 12 pneumonia and 12 congestive heart failure (CHF) patients. RESULTS: Pleural arginase activity in tuberculosis patients was found to be significantly decreased compared to lung cancer and pneumonia groups, while the NO level was higher in tuberculosis patients. All groups except the CHF group had significant correlations between NO level and white blood cell count. Arginase activity and red blood cell count correlated significantly in lung cancer and CHF groups. CONCLUSION: The arginine-NO pathway seems to be involved in the pathogenesis of tuberculous pleural effusion. Decreased arginase activity may cause arginine accumulation, which may then lead to increased NO synthesis by immune and mesothelial cells, reflecting a host defence mechanism.

Effects of cholesterol supplementation on antioxidant enzyme activities in rat hepatic tissues: possible implications of hepatic paraoxonase in atherogenesis.

BACKGROUND AND AIM: The effects of cholesterol supplementation on antioxidant enzyme activities were investigated hepatic tissue taken from Sprague Dawley rats. METHODS AND REULTS: The study involved 14 male Sprague Dawley rats: seven fed a normal laboratory diet and seven a normal diet plus cholesterol (3.6 g/kg/day) for three months, during which blood samples were obtained to measure serum cholesterol levels. At the end of the 3-month period, the livers were surgically removed in order to measure antioxidant enzyme activities (superoxide dismutase, catalase, glutathione peroxidase and paraoxonase-1). At the end of the study period, serum total cholesterol and HDL-cholesterol levels were significantly higher in the cholesterol-fed group than the control group. There were no significant between-group differences in hepatic superoxide dismutase, catalase and glutathione peroxidase activities, but there was a significant decrease in hepatic paraoxonase-1 activity in the cholesterol-fed group. CONCLUSIONS: Cholesterol supplementation significantly decreases paraoxonase-1 activity in rat liver tissue without changing the activities of other antioxidant enzymes. These results suggest that cholesterol significantly suppresses hepatic paraoxonase-1 synthesis. It seems that the decreased paraoxinase-1 activity in the plasma HDL-fraction of atherosclerotic patients is associated with suppressed liver synthesis. A reduction in paraoxonase-1 activity may therefore lead to the more intensive exposure of LDL to oxidant attacks.

Comparison of sedation requirements for cataract surgery under topical anesthesia or retrobulbar block.

PURPOSE: Topical anesthesia is increasingly being used for cataract surgery. However, it is believed that topical anesthesia causes an increased risk of intraoperative complications from unrestricted eye movement and insufficient pain control and more need for sedation. It is difficult to compare pain and anxiety experienced by individual patients; therefore, the authors used the method of patient-controlled sedation to determine whether there is a difference in sedation requirements under topical or retrobulbar anesthesia. METHODS: In this prospective study, patients received either topical anesthesia (n=87) or retrobulbar block (n=104) and self-administered a mixture of midazolam (0.5 mg) and fentanyl (25 microg) in increments using a patient controlled analgesia infuser to achieve sedation. At the end of surgery, patients rated their pain on a 10-point numerical rating scale and their comfort on a 5-point scale. The number of demands and deliveries were noted from the patient controlled analgesia infuser display. RESULTS: Pain scores were between 0 and 2 in 95.4% in the topical and in 94.2% in the retrobulbar group (p>0.05). Patient comfort was equal in both groups with 2.94+/-0.92 in the topical group and 2.92+/-0.99 in the retrobulbar group (p>0.05). Mean sedation requirements were similar in both groups: 26.4% of patients in the topical group and 19.2% in the retrobulbar group did not request any sedation (not significant, p>0.05). CONCLUSIONS: Sedation requirements were similar for cataract surgery under topical and retrobulbar anesthesia.

Comparison of sedation requirements for cataract surgery under topical anesthesia or retrobulbar block.

PURPOSE: Topical anesthesia is increasingly being used for cataract surgery. However, it is believed that topical anesthesia causes an increased risk of intraoperative complications from unrestricted eye movement and insufficient pain control and more need for sedation. It is difficult to compare pain and anxiety experienced by individual patients; therefore, the authors used the method of patient-controlled sedation to determine whether there is a difference in sedation requirements under topical or retrobulbar anesthesia. METHODS: In this prospective study, patients received either topical anesthesia (n=87) or retrobulbar block (n=104) and self-administered a mixture of midazolam (0.5 mg) and fentanyl (25 g) in increments using a patient controlled analgesia infuser to achieve sedation. At the end of surgery, patients rated their pain on a 10-point numerical rating scale and their comfort on a 5-point scale. The number of demands and deliveries were noted from the patient controlled analgesia infuser display. RESULTS: Pain scores were between 0 and 2 in 95.4% in the topical and in 94.2% in the retrobulbar group (p>0.05). Patient comfort was equal in both groups with 2.94 0.92 in the topical group and 2.92 0.99 in the retrobulbar group (p>0.05). Mean sedation requirements were similar in both groups: 26.4% of patients in the topical group and 19.2% in the retrobulbar group did not request any sedation (not significant, p>0.05). CONCLUSIONS: Sedation requirements were similar for cataract surgery under topical and retrobulbar anesthesia. (Eur J Ophthalmol 2004; 14: #-7).

Effects of garlic extract on oxidant/antioxidant status and atherosclerotic plaque formation in rabbit aorta.

BACKGROUND AND AIM: The results of a number of studies suggest that garlic (or garlic extracts) may have favourable effects against the development of atherosclerosis. The aim of this study was to investigate the effects of garlic extract supplementation on oxidant/antioxidant status and atherosclerotic plaque formation in rabbit aortic tissue. METHODS AND RESULTS: Twenty-two male New Zealand White rabbits were fed a cholesterol-supplemented diet (0.5 g/Kg/day) and nine control rabbits a regular diet for four months. At the end of this period, atherosclerotic plaque formation and antioxidant activity were measured in the aortic tissue of the controls and seven of the cholesterol-fed animals. Of the remaining 15 experimental animals, seven were fed normal laboratory diet and eight a normal diet plus garlic extract (1.5 ml/Kg/day) for a further three months before atherosclerotic plaque formation and antioxidant activity were measured in the aortic tissue of both groups. The cholesterol-fed animals showed a significantly impaired antioxidant system associated with increased plaque formation. However, garlic extract supplementation significantly improved antioxidant status and reduced the plaque surface area. CONCLUSIONS: In this experimental model, garlic extract dietary supplementation activated the antioxidant system and decreased peroxidation in aortic tissue. There was also a reduction in atherosclerotic plaque area. Although further studies are required to elucidate the mechanisms involved, the protective activity of garlic extract may be due to its antioxidant properties.

Magnetic resonance imaging characteristics of posterior scleritis mimicking choroidal mass.

We present imaging findings in a case of posterior scleritis, which may mimic tumoral mass lesion resulting in unnecessary enucleation. Magnetic resonance imaging was remarkable for a subretinal mass hypointense on T2 and hyperintense on T1 weighted images. A peripheral rim of hypointensity was noteworthy, suggestive of sclerouveal thickening. There was an ill-defined area of increased T2 signal intensity adjacent to globe at the site of nodular lesion implying an inflammatory process. A linear contrast enhancement was seen within the bulbus oculi which may represent detached retina by exudation or displaced retina due to thickened sclera and choroidal layers. The CSF space around the optic nerve was enlarged.

The role of Tc-99m RBC scintigraphy in the differential diagnosis of orbital cavernous hemangioma.

The cavernous hemangioma is the most common benign orbital tumor in adults. Its presentation is during the forth to fifth decades with a slowly progressive unilateral proptosis. Intraconal cavernous hemangiomas may be difficult to differentiate from other intraconal lesions such as schwannomas, meningiomas and hemangiopericytomas. We report a case of orbital cavernous hemangioma diagnosed by Tc-99m RBC scintigraphy. Tc-99m RBC scintigraphy revealed a typical scintigraphic pattern in which there is intense focally increased uptake on the delayed image. We conclude that Tc-99m RBC scintigraphy can be a useful method in the differential diagnosis of orbital cavernous hemangioma as in hepatic hemangioma.

Early postoperative capsular block syndrome.

PURPOSE: To report the results of early postoperative capsular block syndrome (CBS) after phacoemulsification and intraocular lens (IOL) implantation. SETTING: Department of Ophthalmology, Dokuz Eylül University School of Medicine, Izmir, Turkey. METHODS: Thirteen eyes of 13 patients with CBS who had uneventful phacoemulsification were included in the study. Twelve patients had in-the-bag implantation of a foldable IOL, and 1 had implantation of a poly(methyl methacrylate) IOL in the ciliary sulcus. Continuous curvilinear capsulorhexis was performed in all eyes, and sodium hyaluronate 1.4% (Healon GV(R)) was used during all steps of surgery. The patients were closely followed without intervention during the first month after surgery. If resolution did not occur during follow-up, a neodymium:YAG (Nd:YAG) laser peripheral anterior capsulotomy was performed first, followed by posterior capsulotomy if the anterior capsulotomy was not successful. RESULTS: The CBS resolved without intervention in 2 eyes by 1 month postoperatively. A small Nd:YAG laser peripheral anterior capsulotomy was attempted in 10 cases after 1 month but could not be performed in 2 eyes because of inadequate pupil dilation. Peripheral anterior capsulotomy was successful in 5 of 8 eyes, with resolution of CBS in a few days. The Nd:YAG laser posterior capsulotomy was successful in 5 cases after the failure of the anterior capsulotomy. One patient chose to postpone treatment for 11 months, at which time posterior capsulotomy was performed successfully and the CBS resolved. CONCLUSIONS: Resolution of CBS occurred spontaneously in only a small percentage of cases during the first month after phacoemulsification with IOL implantation. Neodymium:YAG laser peripheral anterior capsulotomy and posterior capsulotomy were successful in treating CBS.

Long-term results of various anterior capsulotomies and radial tears on intraocular lens centration.

BACKGROUND AND OBJECTIVE: To evaluate the long-term effects of various anterior capsulotomies and radial tears on intraocular lens (IOL) centration. MATERIALS AND METHODS: Ninety-five eyes of 87 senile cataract patients operated with extracapsular technique were evaluated in IOL tilt and decentration with a new method of measurement. According to the type of anterior capsulotomy and number of radial tears, five groups were constituted as, can opener, envelope, continous curvilinear capsulorrhexis (CCC), CCC with one radial tear (relaxing incision at quadrant 12), and CCC with two relaxing incisions (relaxing incisions at quadrants 6 and 12), respectively. RESULTS: Early decentration and tilt in groups CCC and CCC with one radial tear were significantly lower than the other groups (P < 0.05). Late decentration and tilt in the CCC group were significantly lower than the other groups (P < 0.01). Highest values of tilt and decentration were determined in envelope capsulotomy. Additional symmetric relaxing incision at quadrant 6 revealed no effect on the prevention of decentration and tilt compared to one relaxing incision. CONCLUSION: CCC with one radial tear is not ideal but sufficient for IOL centration. All other anterior capsulotomy techniques, other than intact CCC, do not guarantee the IOL centration.

Unilateral retinal vasculitis, branch retinal artery occlusion and subsequent retinal neovascularization in Crohn's disease.

PURPOSE: To report on a case of Crohn's disease and unilateral retinal vasculitis, branch retinal artery occlusion and subsequent retinal neovascularization. METHODS: We examined a 38-year-old woman with severe left visual loss and biopsy-proven Crohn's disease diagnosed four years prior to the ocular involvement. A Heidelberg scanning laser ophthalmoscope was used for fundus fluorescein angiography and indocyanine green angiography. Retinal neovascularization was detected during the follow-up. RESULTS: Successful regression of retinal neovascularization was achieved after argon green laser panretinal photocoagulation in addition to oral steroid and salazopyrine. CONCLUSION: Retinal vascular involvement is a rare ocular feature of Crohn's disease and may result in retinal neovascularization that may necessitate prompt laser photocoagulation.

Analysis of the pterygium size inducing marked refractive astigmatism.

PURPOSE: Astigmatic changes induced by the pterygium and their relation to its size and morphology were analysed to establish the critical size for surgery before significant astigmatism occurs. MATERIALS AND METHODS: We evaluated the refraction in 148 eyes of 108 adult patients with primary pterygia. We grouped the astigmatic values according to the keratometric results correlating with the maximal length, width and the approximate total area of the pterigium encroaching on the corneal surface. RESULTS: Pterygia with length or width > or = 3.00 mm were related to significantly higher astigmatism than other groups (p<0.01). The effect of the pterygium morphology on corneal astigmatism was not significant. CONCLUSIONS: Pterygia exceeding 3.00 mm of length or width should be considered within the limits of surgery.

Mucosal antioxidant defense is not impaired in ulcerative colitis.

BACKGROUND/AIMS: In this study, mucosal antioxidant defense was investigated in the biopsy samples from 12 patients with active ulcerative colitis and from 13 patients under remission. METHODOLOGY: Biopsy samples obtained from healthy colon parts of the same subjects were used as control. RESULTS: No changes were observed between superoxide dismutase, glutathione peroxidase and catalase enzyme activities of control or inflamed biopsy samples. However, antioxidant potential values were found to be higher and malondialdehyde levels lower in inflamed samples compared with controls. CONCLUSIONS: Our results show that in contrast to previous suggestions, mucosal antioxidant defense is not impaired in ulcerative colitis.

Acute effects of smoking of cigarettes with different tar content on plasma oxidant/antioxidant status.

In this study, acute effects of two different types of cigarette smoking on plasma oxidant/antioxidant status were investigated. For this purpose, malondialdehyde (MDA) levels and antioxidant potential (AOP) values were measured in the plasma samples before and after cigarette smoking at fasting. After the first blood sample was obtained, second and third samples were withdrawn at 1.5 h and 3 h. In the first group, subjects smoked five cigarettes with full flavor (FF), and in the second group, five cigarettes with full-flavor low tar (FFLT). Quality classification is made mainly on the basis of tar content of the products. The cigarette with 23 mg tar is defined as FF and that with 12 mg tar as FFLT. MDA level was found to be significantly increased in the 1.5-h plasma samples of both groups, but the increase was greater in the FF group. AOP values, however, were found to be lower in the 3-h plasma samples of both groups, but the decrease was greater in the FF group compared with the FFLT group. It appears that acute smoking causes oxidant stress in blood plasma once exposed to smoke, and then this effect (MDA) begins to decrease. On the other hand, AOP is lowered due to oxidant stress created by smoke. With regard to the types of cigarettes, the FF product seems to be more oxidant than the FFLT product. Our results suggest that antioxidant supplementation might be beneficial for the smokers to cope with the oxidant load derived from cigarette smoke. It is also clearly seen from these results that cigarette manufacturers should reduce tar/nicotine ratio in their products in order to lessen the toxic effects of smoking without causing increased need to smoke.