Nitric oxide metabolites as biomarkers for follow-up after chronic rhinosinusitis surgery.

BACKGROUND: Nitric oxide (NO) has a variety of effects on the pathophysiology of the nasal cavity and seems to play an important role in inflammation. It is increased in the common cold but decreased in acute and chronic rhinosinusitis (CRS). Exhaled NO increases after endoscopic sinus surgery in CRS. In our previous study we showed that NO metabolite (nitrate and nitrite) levels are increased in the sinus cavity of CRS patients. We hypothesized that NO metabolite levels are increased to normal in the nasal lavage of CRS patients after endoscopic sinus surgery and NO metabolites in the nasal lavage can be used as indicators of the disease status after surgery. METHODS: This study was performed on 52 patients with CRS who did not respond to medical therapy and who underwent surgery. NO metabolite levels were measured in nasal lavages of the patients before surgery and 2 months after surgery. RESULTS: NO metabolite levels (mean +/- SEM) were 18.11 +/- 3.08 micromol/L and 35.97 +/- 4.64 micromol/L in nasal lavages of patients before and after surgery, respectively. The levels of NO metabolites were increased significantly (p < 0.01) after surgery in nasal lavages and patients reported significant improvement based on the visual analog scoring after the operation. CONCLUSION: NO metabolite levels were decreased in nasal lavages of CRS patients and were increased to normal levels after surgery along with improvement of the disease. NO metabolite levels may be used as an indicator for the follow-up of patients after endoscopic sinus surgery.

Matrix metalloproteinase 2 secretion in WEHI 164 fibrosarcoma cells is nitric oxide-related and modified by morphine.

Matrix metalloproteinases (MMP) are ubiquitous enzymes involved in extracellular matrix remodeling, and as a consequence in a number of physiological and pathological states, including development, wound healing and cancer. A crucial feature of cancer progression and metastasis is the disruption of extracellular matrix, and spreading of proliferating cancer cells. Modulation of MMP is a main target of cancer research. Using the mouse fibrosarcoma cell line WEHI 164, producing high amounts of MMP-2, we investigated whether we could modulate its production. We report that MMP-2 is under the control of nitric oxide (NO)/nitric oxide synthase (NOS) system. In addition, we show that NOS activity is controlled by opioids in a non-opioid receptor-related manner. Finally, we provide evidence that morphine, when administrated at low, non-toxic concentrations (<10(-9) M) attenuates MMP-2 activity. We conclude that, as morphine is able to decrease metalloproteinase activity via the NO/NOS system, it may have a place in the treatment of several sarcomas including fibrosarcoma.

Effect of morphine on ischemia-reperfusion injury: experimental study in testicular torsion rat model.

OBJECTIVES: To investigate the effects of morphine on reperfusion injury due to testicular torsion-detorsion (T/D). METHODS: We divided 36 adult male Sprague-Dawley rats into six groups. Testicular ischemia was achieved by twisting the right testis 720 degrees counterclockwise for 1 hour, and reperfusion was allowed for 4 hours after detorsion. The baseline group was for basal normal values. The sham-operated group served as the control group. The T/D group underwent 1 hour of testicular torsion and 4 hours of detorsion. The morphine group received pretreatment with intravenous morphine sulfate (10 mg/kg) just before detorsion. The naltrexone group received an intravenous injection of naltrexone HCl (20 mg/kg) 15 minutes before detorsion. The naltrexone/morphine group received intravenous administration of naltrexone HCl (20 mg/kg) 15 minutes before detorsion and morphine sulfate (10 mg/kg) just before detorsion. RESULTS: The ipsilateral malondialdehyde levels in the T/D group were significantly greater than in the control and baseline groups. Moreover, the ipsilateral testicular malondialdehyde values in the morphine group were significantly lower than in the T/D and naltrexone/morphine groups. Also, significant decreases occurred in catalase and superoxide dismutase activities in the T/D group compared with the control and baseline groups. These values were significantly greater in the morphine group than in the T/D and naltrexone/morphine groups. The ipsilateral testes of all groups that underwent testicular torsion showed similar histopathologic changes. CONCLUSIONS: Morphine increased the ipsilateral intratesticular antioxidant markers during the reperfusion phase after unilateral testicular torsion, which was eventually reflected in lower testicular malondialdehyde levels. Furthermore, this effect was mediated through the opioid receptors.

Concomitant reduction of matrix metalloproteinase-2 secretion and intracellular reactive oxygen species following anti-sense inhibition of telomerase activity in PC-3 prostate carcinoma cells.

BACKGROUND: The level of activity of the telomerase has been shown to correlate with the degree of invasiveness in several tumor types. In addition, cellular redox state is believed to regulate the secretion of matrix metalloproteinase-2 (MMP-2). AIMS: To determine the effect of anti-sense telomerase treatment of prostate cancer cells on MMP-2 activity, and the reactive oxygen and nitrogen species (two effectors of cellular redox state). METHODS: Anti-sense oligonucleotide against RNA component of human telomerase (hTR) was introduced into the cells using Fugene-6 transfection reagent. The activity of telomerase was assessed using Telomere Repeat Amplification Protocol (TRAP assay). Activity of matrix metalloproteinase-2 (MMP-2) was determined by zymography. Levels of intracellular reactive oxygen species (ROS) and nitric oxide metabolites were measured by dichlorofluorescein diacetate (DCFH-DA) staining and Griess reagent, respectively. The level of apoptosis was determined using TUNEL assay. RESULTS: TRAP assay showed more than 90% inhibition of telomerase activity after 72 h of transfection. Pro-MMP-2 activity was decreased down to 50% of the control levels. Intracellular reactive oxygen species were also significantly decreased. Neither apoptosis rate nor the level of nitric oxide metabolites was significantly different between anti-sense treated and control cells. CONCLUSIONS: Concomitant reduction of the pro-MMP-2 secretion and ROS in PC-3 cells following hTR inhibition suggests that over-activity of telomerase in cancer cells might increase the level of matrix metalloproteinase-2 and thus, be directly involved in the invasion process through enhancement of intracellular oxidative stress.

The synergistic anticonvulsant effect of agmatine and morphine: possible role of alpha 2-adrenoceptors.

Recent demonstrations of the anticonvulsant properties of agmatine suggest it may be considered as a potential adjunct for protection against seizure. We investigated the possibility of an additive anticonvulsant effect between low doses of agmatine and morphine. The thresholds for the clonic seizures induced by the intravenous administration of gamma-aminobutyric acid (GABA)-antagonist, pentylenetetrazole (PTZ) were assessed in mice. Morphine at lower doses (1-3mg/kg) increased and at higher doses (30, 60 mg/kg) decreased the seizure threshold. Pretreatment with a per se non-effective dose of agmatine (1mg/kg) potentiated the anticonvulsant effect of morphine. The combination of subeffective doses of agmatine and morphine led to potent anticonvulsant effects. The pro-convulsant effect of morphine was attenuated by agmatine. Yohimbine with a dose (1mg/kg) incapable of affecting seizure threshold reversed the effect of agmatine on both anticonvulsant and pro-convulsant effects of morphine. These results suggest that agmatine potentiates the anticonvulsant effect of morphine and alpha 2-adrenoceptors may be involved in this effect.

Obstructive cholestasis alters intestinal transit in mice: role of opioid system.

Acute cholestasis is associated with increased activity of the endogenous opioid system. It is also known that opioid receptor agonists like morphine decrease the intestinal transit. The purpose of the present study was to investigate the effect of cholestasis on the small intestine transit and the possible involvement of opioid system in this phenomenon in mice. Cholestasis was induced by bile duct-ligation and intestinal transit was measured with charcoal meal and calculation of percent of transit through small intestine. The effect of chronic administration of naltrexone and acute pretreatment with morphine on intestinal transit was evaluated in bile duct-ligated (BDL) as well as unoperated (CTL) and sham-operated (SHAM) animals. The plasma alkaline phosphatase and alanine aminotransferase activities were also measured. A significant decrease in small intestine transit (%transit) was observed in BDL mice compared to SHAM animals, which was prominent even after 24 h of cholestasis. Chronic pretreatment with an opioid receptor antagonist, naltrexone, (10 mg/kg, i.p for 2, 4 or 6 days) completely restored the cholestasis-induced decrease in %transit to that of control animals. Although the acute administration of morphine (2 mg/kg, s.c.) 20 min before charcoal feeding caused a significant decrease in the intestinal transit of CTL and SHAM animals, it did not decrease the %transit of BDL animals on the day 5 after operation. Our findings show that acute cholestasis is associated with a prominent decrease in small intestine transit in mice and opioid receptors maybe involved in this phenomenon.

Lithium inhibits the modulatory effects of morphine on susceptibility to pentylenetetrazole-induced clonic seizure in mice: involvement of a nitric oxide pathway.

Lithium has been reported to inhibit opioid-induced properties. The present study examined the effect of acute and chronic administration of lithium chloride (LiCl) on morphine's biphasic modulation of susceptibility to pentylenetetrazole (PTZ)-induced clonic seizure in mice. We also examined the possible involvement of nitric oxide (NO) pathway in lithium effect. Both acute (0.1 and 1 mg/kg) and chronic (same doses, 21 consecutive days) administration of LiCl completely inhibited the anticonvulsant and proconvulsant effects of morphine (at doses 1 and 30 mg/kg, respectively). A very low and per se noneffective dose of LiCl (0.05 mg/kg) significantly inhibited both phases of morphine effect when administered concomitant with a noneffective low dose of naloxone (0.1 mg/kg). The NO synthase inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME) at a per se noneffective dose of 0.3 mg/kg potentiated the inhibitory effects of low doses of LiCl (0.01 and 0.05 mg/kg) on both phases of morphine effect. l-arginine, a NO synthase substrate, at a per se noneffective dose of 30 mg/kg reversed the inhibitory effects of lithium (1 mg/kg). Lithium is capable of antagonizing both modulatory effects of morphine on seizure susceptibility even at relatively low doses. These inhibitory effects of lithium may also involve NO synthesis.

Time-dependent reduction of acetylcholine-induced relaxation in corpus cavernosum of cholestatic rats: role of nitric oxide and cyclooxygenase pathway.

The endothelium-dependent relaxation of corpus cavernosum smooth muscle and the roles of nitric oxide (NO) and arachidonic acid products of cyclooxygenase were investigated in non-operated, SHAM-operated, and bile duct-ligated rats. We further investigated the time-dependent alterations of corpus cavernosum relaxation in 2-, 7-, and 14-day bile duct-ligated animals. Acetylcholine produced concentration-dependent relaxation in phenylephrine-precontracted strips of corpus cavernosum. A significant reduction in the acetylcholine-induced relaxation was observed 2 days after bile duct ligation, and a greater reduction was observed on subsequent days. Incubation with 20 microM indomethacin reduced the acetylcholine-induced relaxation of the corpus cavernosum of unoperated rats while it had no effect in the corpus cavernosum of bile duct-ligated rats. Chronic treatment with Nomega-Nitro-L-Arginine Methyl Ester (L-NAME, 3 mg/kg/day, intraperitoneally) reduced the relaxation responses in the unoperated group while it had no effect in the bile duct-ligated group. These results show that acetylcholine-induced corporal relaxation is impaired in cholestatic rats, and this may be related to deficient nitric oxide production by the endothelium. The involvement of prostaglandins in this impairment seems unlikely.