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Biomedical subjects

F C Tulunay

Publications and source records attributed to F C Tulunay.

At least 19 recordsLinked to original sources
PubMed2006

The diffusion of nimesulide gel into synovial fluid: a comparison between administration routes.

BACKGROUND: Nimesulide is available in gel formulation and applied mainly for topical pain management. However, its passage to the synovial fluid is not yet clear. The aim of this study was to evaluate if topical administered nimesulide passes into the synovial fluid and to compare its concentration with the oral nimesulide administration regimen. METHODS: Synovia and plasma nimesulide concentrations were investigated in patients after topical (Sulidin gel 1%) and oral (Mesulid tablet) drug administration. 34 adult outpatients who were scheduled to have an arthroscopic knee examination for mainly meniscal tears repair and who had knee pain during this period were enrolled in the first part of the study. One group received topical nimesulide gel to the skin of the knee whereas the second group received oral 2 x 100 mg nimesulide tablets, 4-7 days before the planned arthroscopy. Synovial fluid and plasma samples were taken simultaneously during the arthroscopy and analyzed using HPLC. In addition, an open-label pilot study was performed to investigate the efficacy and safety of 1-week administration of nimesulide gel. 63 knee osteoarthritis patients were asked to complete the WOMAC Osteoarthritis Index questionnaire before and 1 week after use of Sulidin gel applied 3 times daily. RESULTS: Synovia and plasma nimesulide concentrations were 19.7 +/- 8.6, 11.8 +/- 3.0 and 1958.8 +/- 397.5, 3631.9 +/- 799.3 ng/ ml for topical and oral administration groups, respectively. There was a significant (paired Student's t-test) improvement after 1 week nimesulide treatment in all WOMAC Osteoarthritis Index parameters measured. CONCLUSION: Nimesulide passes into the synovial fluid after topical administration and may have potential benefits in knee osteoarthritis treatment. The actual efficacy and safety of topical nimesulide gel administration should be investigated in a long-term, randomized, placebo-controlled clinical trial.

Administration, Cutaneous↗
PubMed2001

The effect of dipyrone on survival of skin flaps.

The effect of dipyrone on the skin flap survival was studied in a model of an epigastric island flap with a random extension on the opposite side in 23 rats. Dipyrone was given intraperitoneally one hour before the skin flap was raised. At the end of the operation the depth of penetration of the fluorescein dye in the skin flap was assessed visually from photographic records and the flap survival area was measured by a grid method on the seventh postoperative day. There was a significant reduction in the amount of ischaemic necrosis of the skin flap after a single dose of dipyrone 50 mg/kg (p < 0.001). These data suggest that dipyrone is a useful agent in the prevention and treatment of ischaemia and necrosis of the skin flap.

Animals↗
PubMed2000

The vasorelaxant effect of dipyrone on an experimental cerebral vasospasm model in rabbits.

Cerebral vasospasm is an important clinical phenomenon associated with a high mortality rate and therefore any promising findings in the laboratory deserve assessment in clinical practice. Dipyrone (Metamizol) has been in clinical use for its non-narcotic analgesic effect since 1922. In addition to its analgesic effect, dipyrone has been shown to possess spasmolitic activity in various smooth muscle organs. In our recent study, it was shown that dipyrone also has a relaxing effect in vascular smooth muscle preparations and that the smooth muscle relaxing effect on the rabbit thoracic aorta was produced by one of dipyrone's spontaneous degradation products. The present study was designed to examine the possible effects of dipyrone on the rabbit basilar artery in a model of cerebral vasospasm. Dipyrone was shown to have a clear spasmolitic effect in the rabbit basilar artery vasospasm produced by an intracisternal injection of autologous blood. This effect was apparent with either local or intravenous administration of dipyrone. These data suggest that dipyrone is potentially useful in the treatment of patients suffering from cerebral vasospasm in combination with other agents or alone.

Animals↗
PubMed2000

NSAIDs: behind the mechanisms of action.

Non-steroidal anti-inflammatory drugs (NSAIDs) are a heterogeneous group of compounds. These heterogeneous agents have a similar therapeutic action for the treatment of pain, fever and inflammation. The major mechanism of action of NSAIDs is the inhibition of cyclooxygenase (COX), the enzyme catalysing the synthesis of prostaglandins (PGs). Appropriate and effective treatment for migraine depends upon an accurate diagnosis. The goals of treatment are amelioration of the symptoms of an acute attack and prevention of further attacks.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Pharmacological characterization of metamizol-induced relaxation in phenylephrine-precontracted rabbit thoracic aorta smooth muscle.

Metamizol produced a dose- and time-dependent relaxation in rabbit thoracic aorta smooth muscle that was precontracted by phenylephrine. Such a relaxation was not observed with indomethacin, which is also a nonsteroidal anti-inflammatory drug. The relaxing effect of metamizol was independent of the presence of vascular endothelium. Tetraethylammonium (a calcium-activated potassium channel inhibitor), glybenclamide (an ATP-dependent potassium channel inhibitor), indomethacin (a cyclooxygenase inhibitor), and methylene blue (a soluble guanylate cyclase inhibitor) did not have any effect on metamizol-induced relaxation response. Metamizol did not produce any relaxation effect on aortic smooth muscle when KCl (30, 60, and 117 mM KCl) was used instead of phenylephrine to precontract the preparation. Ouabain (a Na-K ATPase pump inhibitor) showed a dose-dependent inhibition on metamizol's relaxation response. However, in potassium-free medium, which is an alternative way to block the Na-K ATPase pump, no inhibition in metamizol-induced relaxation response was observed. When metamizol was incubated for 2 h in organ-bath conditions before evaluating its relaxing effect, it produced a relatively faster relaxation, indicating that the relaxing effect of metamizol is produced by one of its (active) spontaneous degradation products (possibly 4-methylaminoantipyrine).

Animals↗
PubMed1998

Pharmacokinetics of phenprobamate after oral administration to healthy subjects.

Phenprobamate (CAS 673-31-4) is a centrally acting skeletal-muscle relaxant agent. There are only two studies in the literature about the pharmacokinetics of phenoprobamate in man. The inconsistency between the results of these studies can be attributed partly to the different analytical methodologies used. A sensitive, specific and reproducible HPLC-assay, which may increase the reliability of the pharmacokinetic studies of phenprobamate in plasma, has been developed recently. The objective of this investigation was to assess the single-dose kinetics of phenprobamate in human and to determine the pharmacokinetic parameters of clinical and regulatory concern. The plasma pharmacokinetics of phenprobamate have been investigated following single oral administration at a dose of 800 mg in eleven healthy volunteers.

Adolescent↗
PubMed1994

Characteristics of headache in migraine without aura and episodic tension-type headache in the Turkish population according to the IHS classification.

We evaluated the characteristics of headache in migraine without aura and episodic tension-type headache diagnosed according to the International Headache Society (IHS) Classification. Fifty migraine without aura and 50 tension-type headache patients were selected prospectively. Fifty-eight percent of migraineurs had pain of a pulsating quality; 88% had severe pain and 74% had unilateral pain; aggravation by routine physical activity was reported by 96%. Episodic tension-type headache was of a pressing quality in 52%, moderate in 40%, bilateral in 82% and aggravated by routine physical activity in 16%. Nausea and/or vomiting, photophobia and phonophobia were reported significantly more commonly in migraineurs than tension-type headache patients.

Adult↗
PubMed1994

MMPI profiles of Turkish headache sufferers.

The investigations of personality traits have been the issue of many studies on patients with headache. Minnesota Multiphasic Personality Inventory (MMPI) is the most popular assessment instrument used in these studies. MMPI responses of 36 cases (14 male, 22 female) with tension headache and 44 cases (11 male, 33 female) with migraine headache had been compared with 36 nonheadache controls (12 male, 24 female). Because of the inadequate number of male subjects, the statistical analyses were made between female groups. The results obtained revealed that subjects in the tension-type headache group got significantly higher scores on neurotic subtests (hypochondriasis, depression, hysteria) than subjects in the control group. Likewise, migraine subjects got significantly higher scores on hysteria subtest than control subjects. No significant differences were noted between migraine and tension groups. However, none of the headache groups could be characterized by marked elevations on any of the validity and clinical scales. These results, support the finding that neurotic symptoms occur with a higher frequency in headache sufferers.

Adolescent↗
PubMed1992

Role of alpha-adrenoceptors in the effects of buspirone and 5-carboxamidotryptamine in rabbit isolated thoracic aorta.

1. The role of alpha-adrenoceptors in the vascular effects of buspirone (BUS) and 5-carboxamidotryptamine (5-CT) was investigated in rabbit thoracic aorta. 2. Buspirone produced a concentration-dependent contraction. The non-selective 5-HT1 and 5-HT2-receptor antagonist methysergide and the 5-HT2 receptor antagonist ketanserin did not alter the contractile effect of buspirone. However, the competitive antagonist of alpha 1-adrenoceptors, prazosin, shifted the concentration-response curve of buspirone to the right without changing the maximal response. 3. Benextramine tetrahydrochloride monohydrate (BHC), a noncompetitive antagonist of alpha 1-adrenoceptors, inhibited the contraction induced by buspirone in a noncompetitive manner. After pretreatment with two different concentrations of BHC, the estimated apparent dissociation constants of buspirone were found to be identical. 4. In addition, buspirone antagonized the concentration-response curve of phenylephrine again showing a similar dissociation constant, suggesting a partial agonistic action of buspirone at the level of alpha 1-adrenoceptors. 5. The concentration-response curve of 5-HT showed two components in the thoracic aorta obtained from reserpine treated and untreated animals as verified by different pD2 values. The second component was observed with relatively higher concentrations of 5-CT and could be blocked by prazosin or BHC. Neither of these compounds altered the first component. After Pretreatment with BHC, the first component of 5-CT was competitively antagonized by methysergide and ketanserin, having pA2 values of 8.81 and 9.1 respectively. 6. These results suggest that the contraction induced by buspirone is mainly mediated by alpha 1-adrenoceptors, while the higher concentrations of 5-CT caused contraction via alpha 1-adrenoceptor stimulation in addition to its 5-HT2 agonistic effect.

Adrenergic alpha-Antagonists↗
PubMed1992

Effects of calcium channel blockers on formalin-induced nociception and inflammation in rats.

The possible anti-inflammatory and antinociceptive effects of nitrendipine, nicardipine, diltiazem and verapamil were examined with formalin test in the rat paw. Pretreatment with these calcium channel blockers 1 h before formalin injection diminished formalin-induced inflammatory changes and nociceptive responses. Formalin-induced nociceptive responses were inhibited 20-90% by the calcium channel blockers. Nitrendipine and nicardipine were found to be highly effective in inhibiting the inflammatory changes, whereas the effects of verapamil and diltiazem were partial. Administration of naloxone affected neither the inflammatory changes and nociceptive responses induced by formalin nor the antiinflammatory and antinociceptive effects of the calcium channel blockers. The results suggest the possible anti-inflammatory and naloxone-insensitive antinociceptive properties of calcium channel blockers.

Analgesics↗
PubMed1991

Heterogeneous inhibitory effect of nitrendipine on 5-HT-responses in rabbit vascular tissues.

1. Sensitivity of 5-HT2 receptor mediated vascular responses to calcium channel antagonism was investigated in the rabbit thoracic aorta, common carotid artery and main pulmonary artery considering tissue-state of receptor reserve and agonist efficacy. 2. Although 5-HT2 receptor reserve seems to be similar in these preparations, nitrendipine had a heterogeneous inhibitory effect on the contractile response to 5-HT. 3. Reducing 5-HT2 receptor reserve by phenoxybenzamine caused an increase in the inhibitory effect of nitrendipine in these vascular tissues. 4. The vasoconstrictor response induced by 5-carboxyamidotryptamine (5-CT), which is a less potent agonist, showed greater sensitivity to nitrendipine antagonism than the response to 5-HT. 5. The results suggest that efficacy of agonists and tissue-state of receptor reserve seem to be important factors which are partially responsible for the inhibitory effect of nitrendipine on the contractile responses mediated by 5-HT2 receptors.

Animals↗
PubMed1991

The effects of ions on antibacterial activity of ofloxacin and ceftriaxone.

MIC and MBC values of ofloxacin and ceftriaxone were investigated against Staphylococcus aureus in MHB and MHB containing additional Mg2+, Al3+, Fe3+, Ca2+, Zn2+, Cu2+. The addition of Mg2+, Al3+, Fe3+ increased the MIC and MBC of ofloxacin and the MBC of ceftriaxone. However, the addition of these cations did not change the MIC of ceftriaxone. Our findings suggest that these interactions might be due to the formation of chelates between metal ions and antibiotics. These results also indicate that some cations may have an important role in the antibacterial activity of antibiotics.

Cations↗
PubMed1989

Ergotamine enhances acetylcholine-induced relaxation in various vascular segments of rabbits.

The vasodilator response to acetylcholine and-betanechol in segments of rabbit carotid, superior mesenteric and femoral arteries preconstricted with phenylephrine and with intact endothelium was enhanced when the vessels were preincubated with ergotamine but not with ergometrine for 60 min or longer. The vasodilator response to acetylcholine and its enhancement by ergotamine were completely prevented after methylene blue pretreatment or endothelium removal. These results were taken as evidence that the potentiation by ergotamine of the vasodilator response to acetylcholine is probably due to an increased production of EDRF from the vascular endothelium.

Acetylcholine↗
PubMed1987

Dihydroergotamine nasal spray during migraine attacks. A double-blind crossover study with placebo.

Ergot derivatives have been used in the treatment of migraine for more than 50 years. We have compared the efficacy of dihydroergotamine (DHE) nasal spray with that of placebo in patients with classic or common migraine attacks. The study was performed in accordance with a double-blind, crossover design. In this study a great placebo effect was observed with a dose of 1.36 mg/attack, and the overall efficacy was rated by the patients to be 41% and 52% for placebo and DHE, respectively.

Administration, Intranasal↗
PubMed1985

Information processing components of the auditory event related potential are reduced by cocaine.

The effects of cocaine on a human electroencephalographic event related potential (ERP) were measured. Forty-eight subjects received one of three IV doses (0.2, 0.4, or 0.6 mg/kg) and placebo. Thirty-three subjects received one of three oral doses (2, 3, or 4 mg/kg). All IV and oral doses reduced amplitude of the auditory ERP P200 and P300 components during the oddball task. P200 latency decreased. N100 amplitude was reduced only after IV administration. The changes in ERPs occurred during the period of peak cardiovascular and subjective effects. The amplitude reduction in ERP components occurring before the P300 component is consistent with decrements in attention, specifically selective attention. The P300 amplitude reduction after cocaine suggests a disruption of stimulus evaluation resources. The findings are inconsistent with the notion that stimulants affect only response selection and execution. The degree to which stimulants alter cognitive processes prior to response selection may depend on the magnitude of the cardiovascular, subjective, and probably other noncognitive effects.

Administration, Oral↗
PubMed1983

Effect of dynorphin-(1-13) and related peptides on respiratory rate and morphine-induced respiratory rate depression.

Previous studies from our laboratory have shown that the opioid peptide dynorphin-(1-13), although not analgesic when given by itself, can inhibit morphine-induced analgesia in naive mice and potentiate it in morphine tolerant mice. In the present study, we examined the effect of dynorphin-(1-13) with two other dynorphin-like peptides, alpha-neoendorphin and dynorphin-(1-10) amide, on respiration. Our results show that none of the peptides studied had any significant activity on the respiratory rate in mice when given alone. However, in the presence of morphine, dynorphin-(1-13) antagonized the morphine-induced respiratory rate depression in morphine-tolerant animals; alpha-neoendorphin enhanced the morphine-induced respiratory rate depression in naive but had no effect in morphine-tolerant animals and dynorphin-(1-10) amide had no modulatory effect on the morphine-induced respiratory rate depression in either group of animals.

Animals↗