The effect of quercetin on topotecan cytotoxicity in MCF-7 and MDA-MB 231 human breast cancer cells

BACKGROUND: Topotecan, which is a Camptothecin derivative, shows a large spectrum in anti-tumor activity. Topotecan exerts its cytotoxic effect on tumor cells mainly by inhibition of topoisomerase I activity resulting in double-strand DNA breaks. In our study, we investigated the combined cytotoxic action of Topotecan and Quercetin in MCF-7 and MDA-MB 231 human breast cancer cells. To examine the possible relation between the cytotoxic activity of Topotecan and oxidative stress, we measured ROS and nitrite levels in both human breast cell lines. MATERIALS AND METHODS: MCF-7 and MDA-MB 231 cells were exposed to Topotecan, Quercetin, or a combination of both agents for 24 h at 37 degrees C. The viability of the cells was measured using the colorimetric MTT (3-(4,5)-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. We determined reactive oxygen species and nitrite levels as indicators of oxidative stress in both cell lines with and without Topotecan and/or Quercetin incubations using fluorometric dichlorofluorescin diacetate (DCFH-DA) and diaminonaphtalene (DAN) assay. RESULTS: The IC(50) concentration of Topotecan was 100 ng/ml in MCF-7 cell line and 160 ng/ml in MDA-MB231 cell line. Treatment with Quercetin enhanced cytotoxicity of Topotecan as 1.4-fold in MCF-7 and 1.3-fold in MDA-MB-231 cell line. A significant increment on ROS and nitrite levels was found in MCF-7 and MDA-MB-231 cells following Topotecan incubation. CONCLUSIONS: Our results suggest that Topotecan has cytotoxic activity against both of the breast cancer cell lines in vitro. A combination with Quercetin increases efficacy of Topotecan in the treatment of breast cancers. Our results indicate that increased oxidative stress plays a role in the cytotoxic action of Topotecan.     

Radiological outcome of proximal femoral varus osteotomy for the treatment of lateral pillar group-C Legg-Calvé-Perthes disease

Results from 26 hips of 24 Legg-Calvé-Perthes disease patients were evaluated retrospectively. There were 22 male and two female patients in the study group. The mean age of the patients was 8.3 years and the mean follow-up was 13.03 years. All the patients were older than 6 years of age and all of them had lateral pillar group C hips. The patients were treated with intertrochanteric uniplanar varus osteotomy. All the patients were mature at the time of the last evaluation. Radiological end results were evaluated according to Stulberg's classification. Six hips healed with spherical congruency (Stulberg class 1 or 2), 19 with aspherical congruency (Stulberg class 3 or 4) and one with aspherical incongruency (Stulberg class 5). Six of 14 hips treated before 9 years of age healed with spherical congruency but all hips treated after 9 years of age healed with Stulberg class 3, 4 or 5 results. Trochanteric overgrowth was evident in 20 hips. The results of this radiological outcome study showed that Herring class C hips treated with proximal femoral varus osteotomy had a poor outcome, especially after 9 years of age in this group of patients.     

Enhanced tissue factor pathway inhibitor response as a defense mechanism against ongoing local microvascular events of Legg-Calve-Perthes disease

The precise pathogenetic basis of Legg-Calve-Perthes disease (LCPD) is currently unknown. Hemostatic abnormalities, i.e., hypercoagulability and/or hypofibrinolysis, were proposed in the genesis of the LCPD. Deficiency of tissue factor pathway inhibitor (TFPI), a critical natural anticoagulant molecule, may lead to a prothrombotic state in a wide variety of conditions. The aim of this study is to assess the circulating TFPI pool in the LCPD. Group I consisted of 44 patients with LCPD and group II comprised 38 healthy children. Median (IQR) TPFI concentration was significantly higher in the group I (p < .0001). Enhanced TFPI response could be regarded as a compensatory defense mechanism against ongoing local microvascular events of occlusion and revascularization of LCPD. TFPI molecule may be an important link between the crossroads of the LCPD genesis and pathogenetic microvascular changes in the disease course. Further investigations are needed to shed light on the endothelial anticoagulant kinetics, the unique microvascular compromise, and the self-limiting nature of the disease.     

Plasma homocysteine levels in renal transplant patients on tacrolimus therapy

Increased plasma total homocysteine levels afford an independent risk factor to assess cardiovascular morbidity in patients with normal and impaired renal function, including stable transplant recipients. The purpose of this study was to evaluate plasma homocysteine levels and factors known to influence homocysteine metabolism (folate and Vitamin B(12)) in renal transplanted patients treated with tacrolimus. Plasma homocysteine, serum folate and serum vitamin B(12) concentrations were measured in 18 cadaveric renal transplant patients with stable function both before and 3 months after the renal transplantation. While the mean plasma homocysteine level in the renal transplant group was significantly higher than in the control group, no significant change was observed following renal transplantation under tacrolimus therapy (16.84 +/- 6.43 micromol/L vs 16.02 +/- 6.54 micromol/L). The levels of folate before and after transplantation were considerably lower than the control group; a significant effect of tacrolimus has not been observed (7.32 +/- 4.68 ng/mL and 7.55 +/- 5.20 ng/mL). Serum vitamin B(12) levels in the transplant group were significantly lower than the control group; a significant decline was seen 3 months after the renal transplantation (448.94 +/- 230.03 pg/mL vs 334.38 +/- 240.61 pg/mL). Consequently, although plasma homocysteine levels of renal transplant recipients are higher, a lowering effect of tacrolimus therapy was not observed on plasma homocysteine levels. The lower levels of folate and Vitamin B(12) in the transplant group compared to a control group supports therapy with folate and Vitamin B(12) to decrease homocysteine concentrations.     

High-dose exposure to valsartan with suicidal intention

Valsartan is a strong angiotensin receptor inhibitor specific for the angiotensin I receptor, which has been proven safe and well-tolerated in clinical trials. We were able to confirm its safety and tolerability in a case of high-dose exposure to valsartan with suicidal intention. A 25-year-old, fully conscious, female patient was brought to our hospital by relatives on July 24, 2001, at 9:15 p.m. following intake of a high dose of valsartan. It was established that she had taken 28 Diovan 80 mg tablets (2.24 g) 5 hours before admission to the hospital. Her clinical condition at the time of admission was good and did not deteriorate after admission. During the follow-up, her blood pressure never fell below 90/60 mmHg. The only complaint she had were painful muscle cramps which, with only supportive therapy, disappeared spontaneously over 2 days, and her blood pressure also returned to normal during this period. This report demonstrates the effect/side effect profile of valsartan when taken at a high dose, not achievable in a clinical trial.     

Effects of electrohydraulic extracorporeal shock wave lithotripsy on submandibular gland in the rat: electron microscopic evaluation

OBJECTIVES: Extracorporeal shockwave lithotripsy (ESWL) has been applied in sialolithiasis as a new treatment modality. The aim of this experimental study is to investigate the local effects of electrohydraulic ESWL applied to the right submandibular gland of the rats. METHODS: This prospective study was conveyed in four groups; groups I, II, III and IV; each group consisting of 20, 20, 18 and 9 rats, respectively, with a randomized distribution. Groups I, II, III and IV received 250, 500, 1000 and 2000 shock waves at 14-16 kV (average 15.1 kV), respectively, to the right submandibular glands on the 0th day. In groups I, II, III, right submandibular glands of the rats were removed on the 0th, 1st, 7th and 15th days; in group IV, this procedure could be managed only on the 0th and 7th days. Light and electron microscopic evaluation were assessed. Using the light microscopic changes, severity of damage score of the glands (SDS) was found. Statistical analysis was done using SDSs. RESULTS: Light and electron microscopic observations have shown that the damage produced by the shock waves were confined to focal areas in the acinar cells (AC), granulated convoluted tubule (GCT) cells and blood vessels at all doses applied. Vacuolization in the cytoplasms of the AC and GCT cells, disintegration of membranes, alteration in the cytoplasmic organization, swelling of the mitochondria and loss of the features were observed on electron microscopy. Increase in the secretion rate; stasis and dilatation in the blood vessels; blebbing and loss of features in the cytoplasm of the endothelial cells were observed. According to the result of the statistical analysis using SDSs; at 250 shock wave dose, a statistically significant difference between the SDSs of the days (0th, 1st, 7th and 15th) was found (P<0.05). The SDS on the 0th day was found to have the lowest value among the other days. And also a statistically significant difference was found on the 0th day between the SDSs at doses of 250, 500, 1000 and 2000 shock waves (P<0.05). The SDS at 250 and 500 shock waves was found to have the lower value than the SDS at the 2000 shock wave. It was observed that produced damage was less prominent by small doses (250, 500 doses) initially (0th day). Electrohydraulic ESWL caused a "patchy type" generalized pathology on submandibular glands of the rats and damaged focal areas were widespread all through the gland from the 1st day on. CONCLUSION: Formation of the damage was concluded to be related to the direct effect of the shock waves rather than the dose used. Electrohydraulic lithotripters are not suitable for sialolithiasis because of the focus problems, local tissue damage and the risk of the damage to the adjacent structures.