Biomedical subjects

Abdullah Armagan

Publications and source records attributed to Abdullah Armagan.

8 recordsLinked to original sources

PubMed2006

Effects of tamoxifen on vaginal blood flow and epithelial morphology in the rat.

BACKGROUND: Tamoxifen, a selective estrogen receptor modulator with both estrogenic and anti-estrogenic activity, is widely used as adjuvant therapy in breast cancer patients. Treatment with tamoxifen is associated with sexual side effects, such as increased vaginal dryness and pain/discomfort during sexual activity. There have been limited investigations of the effect of tamoxifen on estrogen-dependent peripheral genital arousal responses. The objective of this study was to investigate the effects of tamoxifen on vaginal physiology in the rat. METHODS: Female Sprague-Dawley rats were subjected to sham surgery or bilateral ovariectomy. After 2 weeks, sham-operated rats were implanted with subcutaneous osmotic infusion pumps containing vehicle (control) or tamoxifen (150 microg/day). Ovariectomized rats were similarly infused with vehicle. After an additional 2 weeks, vaginal blood flow responses to pelvic nerve stimulation were measured by laser Doppler flowmetry and vaginal tissue was collected for histological and biochemical assay. RESULTS: Tamoxifen treatment did not change plasma estradiol concentrations relative to control animals, while ovariectomized rats exhibited a 60% decrease in plasma estradiol. Tamoxifen treatment caused a significant decrease in mean uterine weight, but did not alter mean vaginal weight. Vaginal blood flow was significantly decreased in tamoxifen-infused rats compared to controls. Similar to ovariectomized animals, estrogen receptor binding was increased and arginase enzyme activity was decreased in tamoxifen-infused rats. However, different from control and ovariectomized animals, the vaginal epithelium in tamoxifen-infused rats appeared highly mucified. Periodic acid-Schiff staining confirmed a greater production of carbohydrate-rich compounds (e.g. mucin, glycogen) by the vaginal epithelium of tamoxifen-infused rats. CONCLUSION: The observations suggest that tamoxifen exerts both anti-estrogenic and pro-estrogenic effects in the vagina. These physiological alterations may eventually lead to vaginal atrophy and compromise sexual function.

Journal Article↗

PubMed2006

Effects of melatonin on lipid peroxidation and antioxidant enzymes in streptozotocin-induced diabetic rat testis.

AIM: To examine the effects of melatonin treatment on lipid peroxidation (LPO) and the activities of antioxidant enzymes in the testicular tissue of streptozotocin (STZ)-induced diabetic rats. METHODS: Twenty-six male rats were randomly divided into three groups as follows: group I, control, non-diabetic rats (n = 9); group II, STZ-induced, untreated diabetic rats (n = 8); group III, STZ-induced, melatonin-treated (dose of 10 mg/kg . day) diabetic rats (n = 9). Following 8-week melatonin treatment, all rats were anaesthetized and then were killed to remove testes from the scrotum. RESULTS: As compared to group I, in rat testicular tissues of group II , increased levels of malondialdehyde (MDA) (P < 0.01) and superoxide dismutase (SOD) (P < 0.01) as well as decreased levels of catalase (CAT) (P < 0.01) and glutathione peroxidase (GSH-Px) (P > 0.05) were found. In contrast, as compared to group II, in rat testicular tissues of group III, levels of MDA decreased (but this decrease was not significant, P > 0.05) and SOD (P < 0.01) as well as CAT (P < 0.05) increased. GSH-Px was not influenced by any of the treatment. Melatonin did not significantly affect the elevated glucose concentration of diabetic group. At the end of the study, there was no significant difference between the melatonin-treated group and the untreated group by means of body and testicular weight. CONCLUSION: Diabetes mellitus increases oxidative stress and melatonin inhibits lipid peroxidation and might regulate the activities of antioxidant enzymes of diabetic rat testes.

Animals↗

PubMed2006

Dose-response relationship between testosterone and erectile function: evidence for the existence of a critical threshold.

Androgens play an important role in erectile function. However, the dose-response relationship between plasma testosterone levels and penile erection remains unclear. Intact (sham operated) or bilaterally orchiectomized, mature male Sprague-Dawley rats were used. Two weeks after surgery, rats were infused continuously with either vehicle (polyethyleneglycol) or varying doses of testosterone (44, 88, 220, or 440 mug/day) for 14 days using subcutaneous osmotic infusion pumps (study 1). In a separate study, 4 weeks after surgery, rats were infused with a lower range of testosterone doses (11, 22, or 44 mug/day) for 14 days (study 2). In the first study, intact rats had a mean plasma testosterone concentration of 0.56 +/- 0.12 ng/mL ( approximately 1.9 nM), as determined by standard radioimmunoassay. In the second study, a more sensitive enzyme-linked immunoassay was used to measure the lower testosterone levels. Using this assay, intact rats had a mean plasma testosterone concentration of 2.02 +/- 0.59 ng/mL. Intracavernosal pressure measurements indicated that orchiectomy resulted in a significant reduction in erectile function, when compared to intact animals, whereas testosterone infusion restored erectile function to varying degrees. Erectile function was maintained by a wide range of systemic testosterone levels as low as 10%-12% of normal physiological plasma concentrations. Below these concentrations, erectile function was significantly and positively correlated with testosterone plasma levels in a dose-dependent manner. Interestingly, prostate tissue mass was positively correlated to plasma testosterone levels across all concentrations examined. Protein expression of neural nitric oxide synthase (nNOS) and phosphodiesterase type 5 (PDE 5) was reduced in penile tissue from orchiectomized animals and increased in testosterone-infused animals, as assessed by Western blot analyses. We suggest that testosterone at levels approaching one-tenth normal physiological plasma concentration may represent a threshold value, below which erectile function declines in a dose-dependent fashion. However, different androgen-dependent tissues may exhibit varying sensitivities to circulating testosterone with regard to growth and function.

Animals↗

PubMed2005

A novel antioxidant agent caffeic acid phenethyl ester prevents shock wave-induced renal tubular oxidative stress.

The aim of this study was to evaluate the effects of the novel free radical scavenger caffeic acid phenethyl ester (CAPE) on extracorporeal shock wave lithotripsy (ESWL) induced renal impairment. The study was performed using 30 rabbits which were divided into two groups, each exposed to 3,000 shock waves at 18 kV: (1) control group, (2) ESWL+CAPE treated group. Malodialdehyde (MDA), urine N-acetyl-beta-glucosaminidase (NAG) activity, uric acid and white cell counts were used as markers of oxidative stress. Following shock wave exposure there was a significant rise in MDA, NAG and uric acid and white cell counts. CAPE reduced the rise in MDA, NAG, uric acid and white cell counts. Thus CAPE treatment to a great extent prevented the induction of these renal changes. Our results suggest that the antioxidant capacity of the kidney tissue was reduced after ESWL treatment and that the tissue was exposed to oxidant stress. We conclude that CAPE treatment provided significant protection against ESWL induced free radical damage.

Acetylglucosaminidase↗

PubMed2005

Comparative analysis of the protective effects of melatonin and caffeic acid phenethyl ester (CAPE) on mobile phone-induced renal impairment in rat.

Melatonin and caffeic acid phenethyl ester (CAPE), a component of honeybee propolis, were recently found to be potent free radical scavengers and antioxidants. There are a number of reports on the effects induced by electromagnetic radiation (EMR) in various cellular systems. Mechanisms of adverse effects of EMR indicate that reactive oxygen species may play a role in the biological effects of this radiation. The present study was carried out to compare the protective effects of melatonin and CAPE against 900 MHz EMR emitted mobile phone-induced renal tubular injury. Melatonin was administered whereas CAPE was given for 10 days before the exposure. Urinary N-acetyl-beta-D-glucosaminidase (NAG, a marker of renal tubular injury) and malondialdehyde (MDA, an index of lipid peroxidation), were used as markers of oxidative stress-induced renal impairment in rats exposed to EMR. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were studied to evaluate the changes of antioxidant status in renal tissue. Urinary NAG and renal MDA were increased in EMR exposed rats while both melatonin and CAPE caused a significant reduction in the levels of these parameters. Likewise, renal SOD and GSH-Px activities were decreased in EMR exposed animals while melatonin caused a significant increase in the activities of these antioxidant enzymes but CAPE did not. Melatonin caused a significant decrease in urinary NAG activity and MDA levels which were increased because of EMR exposure. CAPE also reduced elevated MDA levels in EMR exposed renal tissue, but the effect of melatonin was more potent than that of CAPE. Furthermore, treatment of EMR exposed rats with melatonin increased activities of SOD and GSH-Px to higher levels than those of control rats. In conclusion, melatonin and CAPE prevent renal tubular injury by reducing oxidative stress and protect the kidney from oxidative damage induced by 900 MHz mobile phone. Nevertheless, melatonin seems to be a more potent antioxidant compared with CAPE in kidney.

Acetylglucosaminidase↗

PubMed2004

Penile vascular abnormalities observed long-term after surgical repair of penile fractures.

AIM: To assess the penile vascular system in men long-term after surgical treatment of penile fractures. PATIENTS AND METHODS: During a 15-year period, 36 cases of penile fracture underwent immediate surgical repair at the University of Istanbul, Turkey. At least 1 year after operation, all patients were invited for penile vascular evaluation. 15 patients accepted our call and were enrolled in our study. They were evaluated with detailed medical and sexual history, a serial of serum analyses, and penile color Doppler ultrasonography. RESULTS: By history, 6 of the 36 (16.6%) patients who had undergone surgical repair had erectile dysfunction (ED). The mean interval between surgical intervention for penile fracture and penile vascular evaluation was 3.6 +/- 1.9 (range 1.5-8) years. Evaluation of the penile vascular system of 15 men (mean age 35.7 +/- 17.3, range 21-63 years) revealed normal vascular system in seven (46.7%), while cavernosal insufficiency was observed in four (26.7%) and arterial insufficiency in three (20%) men. The remaining case (6.7%) was diagnosed to have mixed arterial and cavernous insufficiency. Erectile dysfunction in two cases was considered to be in psychogenic origin and vascular in the remaining four. CONCLUSION: Although immediate repair is reported to be the treatment of choice in penile fractures, ED of either a physiological or vascular origin can be encountered as a long-term sequel and deserves to be evaluated in detail.

Adult↗

PubMed2003

Metabolic risk factors in pediatric and adult calcium oxalate urinary stone formers: is there any difference?

OBJECTIVES: Urolithiasis in children is recognized with an increasing frequency, while exact etiological factors remain to be determined. The aim of this study is to compare the metabolic risk factors and saturation of urine in pediatric and adult calcium oxalate (Ca-Ox) stone formers. METHODS: A total of 33 pediatric (mean age: 6.8 +/- 3.1 years) and 120 adult patients (mean age: 39.7 +/- 5.7 years), with documented Ca-Ox urinary stone disease, underwent a comprehensive metabolic evaluation at our institution. Beside a broad serum analysis, concentrations of calcium, oxalate, magnesium, uric acid and citrate were measured in 24-hour collected urine. Saturation of urine was calculated by Marshall-Robertson's nomograms. RESULTS: Hypocitraturia, observed in 60.6%, and hypomagnesuria, detected in 39.4%, but not hypercalciuria, were the most common metabolic risk factors in the pediatric group. In adults, hypercalciuria still represented one of the major metabolic risk factors, detected in 44.1%, although hypocitraturia, observed in 45.8%, was the most prevalent metabolic risk factor, as it was in the pediatric group. Pediatric cases had significantly (p < 0.05) higher prevalence of hypocitraturia, hypomagnesuria and supersaturated urine when compared to adults. Metabolic abnormalities could be detected in a high percentage (82%) of primary and recurrent pediatric Ca-Ox stone formers, but not in primary adult stone formers. CONCLUSIONS: Metabolic risk factors significantly differ in pediatric and adult Ca-Ox stone formers. Hypocitraturia and hypomagnesuria seem to play a major role in stone formation, and metabolic abnormalities can be detected in a significant percentage of both primary and recurrent pediatric stone formers. Thus, a comprehensive metabolic evaluation is of utmost importance for all children with Ca-Ox stones.

Adult↗

PubMed2002

Effects of extra-corporeal shock waves on penile hemodynamics and histopathology in rats.

AIM: To study the effect of extra-corporeal shock wave (ESW) on the penile hemodynamics and histopathology in rats. METHODS: Adult male Sprague-Dawley rats were divided at random into 3 groups. ESW application was performed with a Siemens Lithostar with the rats under anesthesia lying prone on the balloon probe. Rats in Group I received a total of 1000 shocks at 18 kV and immediately underwent hemodynamic evaluation performed by direct electrostimulation of the cavernous nerve and measurement of intracavernous pressure (ICP). Rats in Group II received 3 times 1000 shocks at 18 kV at weekly intervals and hemodynamic evaluation was performed 1 month after the last ESW application. Group III served as the control. Histopathological examinations of penile tissues were done on Masson's trichrome and hematoxylin and eosin stained sections. RESULTS: Penile hemodynamic evaluation showed a trend toward a diminished mean maximal ICP, duration of erection, ICP during the plateau phase and maximal ICP/ blood pressure ratio in Group I, although there was no significant significance. The mean latency period in Groups I and II was prolonged. Petechial bleeding within tunical layers and small foci of hemorrhage within the corpora cavernosa were observed in Group I. However, histopathological examination failed to reveal any significant differences between the groups in terms of smooth muscle content, tunical thickness, organization of collagen bundles and elastic fiber-lattice framework. CONCLUSION: ESW has certain damaging effects on the penis.

Animals↗