Orhan Uludag

High-fructose corn syrup causes vascular dysfunction associated with metabolic disturbance in rats: Protective effect of resveratrol

High-fructose corn syrup (HFCS) is used in many prepared foods and soft drinks. However, limited data is available on the consequences of HFCS consumption on metabolic and cardiovascular functions. This study was, therefore, designed to assess whether HFCS drinking influences the endothelial and vascular function in association with metabolic disturbances in rats. Additionally, resveratrol was tested at challenge with HFCS. We investigated the effects of HFCS (10% and 20%) and resveratrol (50mg/l) beverages on several metabolic parameters as well as endothelial relaxation, vascular contractions, expressions of endothelial nitric oxide synthase (eNOS), sirtuin 1 (SIRT1), gp91(phox) and p22(phox) proteins and superoxide generation in the aortas. Consumption of HFCS (20%) increased serum triglyceride, VLDL and insulin levels as well as blood pressure. Impaired relaxation to acetylcholine and intensified contractions to phenylephrine and angiotensin II were associated with decreased eNOS and SIRT1 whereas increased gp91(phox) and p22(phox) proteins, along with provoked superoxide production in the aortas from HFCS-treated rats. Resveratrol supplementation efficiently restored HFCS-induced deteriorations. Thus, intake of HFCS leads to vascular dysfunction by decreasing vasoprotective factors and provoking oxidative stress in association with metabolic disturbances. Resveratrol has a protective potential against the harmful consequences of HFCS consumption.

Recovery of Fertility in Azoospermia Rats after Injection of Adipose-Tissue-Derived Mesenchymal Stem Cells: The Sperm Generation

The recent reports on the treatment of azoospermia patients, in which spermatozoa could not be traced in their testes, are focused more on the potential use of adult stem cells, like mesenchymal stem cells (MSCs). The aim of this study was to demonstrate the potential use of MSCs derived from adipose tissue in the treatment of azoospermia using rat disease models. After busulfan application, the rats (n = 20) were injected with the GFP+ MSCs into left rete testes. After 12 weeks, the testes with cell injection (right testes) were compared to control (left testes) after dimensional and immunohistochemical analyses. Testes treated with MSCs appeared morphologically normal, but they were atrophic in rats without stem cell treatment, in which the seminiferous tubules were empty. Spermatogenesis was detected, not in every but in some tubules of cell-treated testes. GFP+/VASA+ and GFP+/SCP1+ cells in testes indicated the transdifferentiation of MSCs into spermatogenetic cells in the appropriate microenvironment. Rats with cell treatment were mated to show the full recovery of spermatogenesis, and continuous generations were obtained. The expression of GFP was detected in the mesenchymal stem cells derived from adipose tissue and bone marrow and also in the sperms of offspring. In conclusion, MSCs might be studied for the same purpose in humans in future.

Effects of cyclooxygenase inhibitors on nitric oxide production and survival in a mice model of sepsis.

The effects of selective ((5,5-dimethyl-3-(3-florophenyl)-4-(4-methylsulphonyl-2(5H)-furanon); DFU) and (N-(2-cyclohexyloxy-4-nitrophenyl)-methansulphonamide; NS 398)) or non-selective (diclophenac and proquazon) inducible cyclooxygenase (COX-2) inhibitors on the survival, nitrite (stable product of nitric oxide (NO) as an index for inducible NO synthase (iNOS) activity) and 6-keto-prostaglandin F(1alpha) (6-keto-PGF(1alpha), stable product of prostacyclin as an index for COX-2 activity) production in serum, lungs, brain and/or kidney were investigated in endotoxin-induced sepsis model in mice. Endotoxin (10 mg x kg(-1), i.p.)-induced mortality was prevented by DFU, NS 398 and proquazon (0.1, 10 and 1 mg x kg(-1), respectively) and enhanced 2.6-fold with 0.1mg x kg(-1) diclophenac. Endotoxin-induced increase in the serum levels of nitrite was only inhibited by 10 mg x kg(-1) diclophenac. Endotoxin caused a significant decrease only in the brain levels of nitrite without affecting 6-keto-PGF(1alpha) levels in all tissues. The decreased levels of nitrite induced by endotoxin is further reduced by 0.1mg x kg(-1) DFU and 1 and 10mg x kg(-1) diclophenac while 10 mg x kg(-1) DFU and 1mg x kg(-1) proquazon increased it. On the other hand, 1mg x kg(-1) diclophenac and proquazon, and 10 mg x kg(-1) NS 398 increased the endotoxin-induced lung levels of 6-keto-PGF(1alpha). The results suggest that the COX inhibitors may have different effects on the survival and NO production depending on tissue and dose.

Synthesis and evaluation of analgesic, anti-inflammatory, and anticancer activities of new pyrazole-3(5)-carboxylic acid derivatives

In this article, we synthesized a series of novel 1-benzyl-5(3)-p-tolyl-1H-pyrazole-3(5)-carboxylic acid derivatives and characterized by IR, 1H NMR, and mass spectroscopy. Compounds were evaluated for their in vivo analgesic and anti-inflammatory activity using the p-benzoquinone-induced writhing test and the carrageenan-induced paw edema model, respectively. Out of 14 compounds tested, 7a, 7c, 7e, 7f, 7i, 8a–b, and 8f–g exhibited potent analgesic and/or anti-inflammatory activity as compared to reference drugs aspirin and indomethacin. Anticancer activity of these compounds was assessed against five cancer cell lines with the MTT assay (HL-60, human promyelocytic leukemia cells; HeLa, human cervical cancer cells; Raji, human B lymphocyte cell line; MCF7, human breast adenocarcinoma cell line; MDA-MB-231, estrogen-independent human breast cancer cell line). Compounds 7a, 8a, and 8b with high anti-inflammatory activity, and also 7d and 7j with mild anti-inflammatory activity exhibited promising anticancer activity against some selected cell lines.

Time-Dependent Variations in Serum Nitrite, 6-Keto-Prostaglandin F1α and Thromboxane B2 Levels Induced by Lipopolysaccharide in Mice

Clinical features of certain immuno-inflammatory disorders exhibit time-dependent fluctuations, which could be related to circadian rhythmicity of proinflammatory mediator production. Many biologically active substances including nitric oxide (NO) and eicosanoids are released into the circulation in sepsis. Increased NO and eicosanoid levels have been reported to be responsible from death in septic shock. The aim of this study was to investigate the variations in the NO and eicosanoid production and mortality induced by bacterial endotoxin, lipopolysaccharide (LPS) injected either in the morning or in the evening. Experiments were performed on mice synchronised to 12 h light and 12 h dark (lights on at 09:00 h). Animals were injected intraperitoneally with LPS (10 mg/kg) at 09:00 (morning) and 21:00 h (evening) alone or in combination with aminoguanidine (NO synthase (NOS) inhibitor) (100 mg/kg) or indomethacin (cyclooxygenase (COX) inhibitor) (100 mg/kg). The serum was separated from blood samples obtained at nine different time points. Nitrite (stable product of NO), 6-keto-prostaglandin F1α (6-keto-PGF1α, stable product of prostacyclin) and thromboxane B2 (TxB2, stable product of thromboxane) concentrations in serum samples were measured. Serum nitrite levels showed a 24 h circadian rhythmicity depending on LPS injection time. Morning injection caused a peak after 15 h, while evening injection had two peaks after 9 and 18 h. The peak values obtained from morning and evening injections were significantly decreased by aminoguanidine and indomethacin. When LPS injected to mice in the morning and in the evening, it gradually increased the mortality rate within 24 h which could be abolished by aminoguanidine, but not indomethacin. Indomethacin-induced inhibition on LPS-induced nitrite levels was higher in the morning than in the evening. 6-keto-PGF1α and TxB2 levels were decreased by indomethacin when injected with LPS at both injection times, but not aminoguanidine. These results showed that there is an interaction between NO and eicosanoids, and LPS may produce different effects on NOS activity, but not eicosanoid production and mortality, depending on injection time in the experimental septic shock model in mice. Chronopharmacological manipulations of NOS and COX pathways and interactions between them could lead to novel therapeutic approaches for the treatment of septic shock.

Circadian-rhythm-dependent effects of l-nG-nitroarginine methyl ester (L-name) on morphine-induced analgesia

Circadian changes in the interactions between L-NG-nitroarginine methyl ester (L-NAME), a nitric oxide synthase (NOS) inhibitor, and morphine-induced antinociception were investigated by the mouse hot-plate test. Both the basal pain sensitivity and morphine-induced analgesia undergo significant 24 h variations. L-NAME (40 mg/kg, i.p.) alone did not show any antinociceptive activity, but potentiated morphine-induced analgesia when combined with morphine at all injection times. In terms of percentage absolute potentiation (%AP), L-NAME dramatically augmented the analgesic effect of morphine in the late dark period at 19 hours after lights on (HALO). It is concluded that nitric oxide (NO) is involved in the modulation of the analgesic effect of morphine; thus, the L-NAME and morphine combination might be beneficial in alleviating pain.

Biological Time‐Dependent Difference in Effect of Peroxynitrite Demonstrated by the Mouse Hot Plate Pain Model

We previously demonstrated the rhythmic pattern of L‐arginine/nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) cascade in nociceptive processes. The coupled production of excess NO and superoxide leads to the formation of an unstable intermediate peroxynitrite, which is primarily responsible for NO‐mediated toxicity. In the present study, we evaluated the biological time‐dependent effects of exogenously administered peroxynitrite on nociceptive processes and peroxynitrite‐induced changes in the analgesic effect of morphine using the mouse hot‐plate pain model. Experiments were performed at four different times of day (1, 7, 13, and 19 hours after lights on, i.e., HALO) in mice of both sexes synchronized to a 12 h:12 h light‐dark cycle. Animals were injected intraperitoneally (i.p.) with saline or 10 mg/kg morphine 30 min before and 0.001 mg/kg peroxynitrite 30 sec before hot‐plate testing, respectively. The analgesic effect of morphine exhibited significant biological time‐dependent differences in the thermally‐induced algesia; whereas, administration of peroxynitrite alone exhibited either significant algesic or analgesic effect, depending on the circadian time of its injection. Concomitant administration of peroxynitrite and morphine reduced morphine‐induced analgesia at three of the four different study time points. In conclusion, peroxynitrite displayed nociceptive and antinociceptive when administered alone according to the circadian time of treatment, while it diminished analgesic activity when administered in combination with morphine at certain biological times.

Temporal variation in serum nitrite levels in rats and mice.

Although considerable evidence implicates involvement of nitric oxide (NO) in circadian regulation, little is known about possible 24 h variations in basal NO metabolism. In this study, daily variations in serum nitrite levels were studied in locally bred mice and rats during the months of September and October. The serum was separated from blood samples obtained at six different times of the day and night (1 h, 5 h, 9 h, 13 h, 17 h, and 21 h after lights off [HALO] from male albino mice and rats). As an index of in vivo NO generation, serum nitrite levels (determined by the diazotization method) in rats exhibited significant temporal fluctuation (unpaired Student t test), with the concentration highest at 5 HALO and 21 HALO and lowest at 9 HALO. No such temporal variation was detected in mice in these studies conducted on locally bred animals in the autumn.

Twenty‐Four‐Hour Variation of L‐Arginine/Nitric Oxide/Cyclic Guanosine Monophosphate Pathway Demonstrated by the Mouse Visceral Pain Model

The L‐arginine/nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway is known to be involved in central and peripheral nociceptive processes. This study evaluated the rhythmic pattern of the L‐arginine/NO/cGMP pathway using the mouse visceral pain model. Experiments were performed at six different times (1, 5, 9, 13, 17, and 21 h after light on) per day in male mice synchronized to a 12 h:12 h light‐dark cycle. Animals were injected s.c. with saline, 2 mg/kg L‐arginine (a NO precursor), 75 mg/kg L‐NG‐nitroarginine methyl ester (L‐NAME, a NOS inhibitor), 40 mg/kg methylene blue (a soluble guanylyl cyclase and/or NOS inhibitor), or 0.1 mg/kg sodium nitroprusside (a nonenzymatic NO donor) 15 min before counting 2.5 mg/kg (i.p.) p‐benzoquinone (PBQ)‐induced abdominal constrictions for 15 min. Blood samples were collected after the test, and the nitrite concentration was determined in serum samples. L‐arginine or L‐NAME caused both antinociception and nociception, depending on the circadian time of their injection. The analgesic effect of methylene blue or sodium nitroprusside exhibited significant biological time‐dependent differences in PBQ‐induced abdominal constrictions. Serum nitrite levels also displayed a significant 24 h variation in mice injected with PBQ, L‐NAME, methylene blue, or sodium nitroprusside, but not saline or L‐arginine. These results suggest that components of L‐arginine/NO/cGMP pathway exhibit biological time‐dependent effects on visceral nociceptive process.

High-sensitive troponin T increase after hemodialysis is associated with left ventricular global longitudinal strain and ultrafiltration rate

BACKGROUND Circulating troponin levels are both stable and higher in patients with end-stage renal disease, even in the absence of acute coronary syndrome. These patients commonly have underlying cardiac problems that frequently cause troponin elevation. The effect of hemodialysis (HD) on troponin levels has not been well elucidated. Thus, investigated herein is the relationship between the changes in troponin levels along with left ventricular deformation and volume depletion in patients with end-stage renal disease. METHODS Patients included were between 18 and 85 years of age and were receiving hemodialysis for at least 6 months. High sensitive cardiac troponin T (hs-cTnT) levels were studied in blood samples taken at the beginning and end of HD. Two-dimensional speckle tracking strain imaging was used to evaluate myocardial contractility. RESULTS Seventy patients (50.7 ± 16.9 years of age, 27 women) were included in study. The mean volume of ultrafiltration was 3260 ± 990 mL. A significant increase in circulating hs-cTnT levels was observed, as well as a prominent decrease in left ventricular global longitudinal strain (GLS) after HD (52.4 ± 40.2 ng/L vs. 66.8 ± 48.5 ng/L, p < 0.001 and 20.1 ± 3.6% vs. 16.8 ± 3.8% p < 0.001, respectively). Moreover, ultrafiltration rate and GLS were found as the strongest independent variables in relation to the relative increase in hs-cTnT. CONCLUSIONS Hemodialysis can cause a significant increase in hsTnT. This can jeopardize the accuracy of clinical diagnoses based on hs-TnT measurements. GLS may be used as a determinant of this hs-TnT increase. The influence of HD on the cardiovascular system should be kept in mind to prevent unnecessary interventions.