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Biomedical subjects

A Bozkurt

Publications and source records attributed to A Bozkurt.

79 records · Page 5Linked to original sources
PubMedDate not supplied

Omission of the deconjugation step in urine analysis and the unaltered outcome of CYP2D6 phenotyping with dextromethorphan.

The present study was aimed at determining whether the deconjugation step in chemical analysis could be omitted without altering the outcome of phenotyping CYP2D6 with dextromethorphan. This drug and its metabolite, dextrorphan, were assayed by high-performance liquid chromatography (HPLC) in urine. Urinary levels of dextromethorphan and dextrorphan with and without enzymatic (beta-glucuronidase) treatment of urine and the metabolic ratios for dextromethorphan were determined in 45 subjects. Although the enzymatic treatment did not alter the urinary concentration of dextromethorphan in both phenotypes, it increased the urinary concentration of dextrorphan in both poor and extensive metabolizers by 3.7- and 12.8-fold, respectively. A urinary unconjugated dextromethorphan/unconjugated dextrorphan metabolic ratio of 2.00 and a total dextromethorphan/total dextrorphan metabolic ratio of 0.30, respectively, identified three poor metabolizers. Enzymatic treatment decreased the urinary antimode value. Moreover, the urinary metabolic ratio based on unconjugated dextrorphan and dextromethorphan correlated well with that based on assay of total dextrorphan and dextromethorphan (rs = 0.9458, P < 0.001). The results show that urinary analysis of dextrorphan and dextromethorphan omitting the enzymatic deconjugation step is a fast, reliable and sensitive method and could be used for studying CYP2D6 type genetic polymorphism in man.

Adolescent↗
PubMedDate not supplied

Analgesic effect of aspirin, mefenamic acid and their combination in post-operative oral surgery pain.

A double-blind randomized single dose study of the analgesic effects of 650 mg aspirin, 250 mg mefenamic acid, the combination of 650 mg aspirin and 250 mg mefenamic acid and placebo on 120 patients with pain following oral surgery was conducted. Patients evaluated their pain intensity and extent of pain relief at 1, 2, 3 and 4 h after drug administration. For most parameters, including the sum of the pain intensity differences and the sum of the hourly pain relief scores, each of the drugs was more effective than placebo. Aspirin-mefenamic acid in combination was more effective than both drugs alone, and aspirin and mefenamic acid alone were equally effective for most of the analgesic variables.

Analgesics↗
PubMedDate not supplied

The pharmacokinetics and effects of diltiazem in rabbits.

PURPOSE: To investigate the effect of diltiazem on wound healing after the creation of conjunctival flaps in rabbit eyes. Also, to investigate the pharmacokinetics of diltiazem in rabbits after subconjunctival and topical administration. METHODS: For the histopathological study, a limbal-based flap was prepared and diltiazem was injected subconjunctivally for five days after the surgery. The rabbits were euthanised 20 days after surgery. The effectiveness of diltiazem on wound healing was evaluated by histopathological examination and measurement of the thickness of subconjunctival fibrous tissue. For the pharmacokinetic study, diltiazem was applied topically or injected subconjunctivally. Aqueous paracenteses were performed 0.5, 1, 2, 4 hours thereafter. RESULTS: The histopathological study found no difference in thickness of the subconjunctival fibrous tissue in control and diltiazem-treated eyes. No significant toxicity was observed in eyes treated with diltiazem. The peak aqueous concentration was 3.8 +/- 0.4 microg/ml after topical application and 15.3 +/- 1.1 microg/ml after subconjunctival injection. The peak aqueous concentration was achieved 1/2 hours after administration in both cases. CONCLUSIONS: Diltiazem did not appear to affect wound healing at the dose tested. Topical and subconjunctival diltiazem successfully penetrated the aqueous humor of rabbit eyes.

Animals↗
PubMedDate not supplied

Intraocular pressure, quality of block, and degree of pain associated with ropivacaine in peribulbar block: a comparative randomized study with bupivacaine-lidocaine mixture.

PURPOSE: To compare the effects of ropivacaine and bupivacaine-lidocaine combination on intraocular pressure, quality of block, and degree of postoperative pain in peribulbar block. METHODS: The study group involved 32 patients undergoing elective cataract surgery under peribulbar block. Patients were divided into two groups according to the local anesthetic used: Group 1 (n = 16), ropivacaine 0.75%; and Group 2 (n = 16), bupivacaine 0.5%-lidocaine 2% mixture. Intraocular pressure was measured at four time points: before block (control), 1 min after block, 5 min after block, and 15 min after block with Tonopen. Quality of block was evaluated using a three-point scoring system based on the reduction of globe motility. Patients were asked their degree of intraoperative pain by using a five-point verbal rating score after the surgery. RESULTS: Mean values of intraocular pressure after block were significantly lower in Group 1 in comparison to Group 2 (p < 0.05, Mann Whitney test). The quality of block was better in Group 2, and the degree of postoperative pain was lower in Group 1 (p < 0.05, Mann-Whitney test). CONCLUSIONS: Ropivacaine used in peribulbar block is better than bupivacaine-lidocaine mixture under the same standard conditions in terms of reducing intraocular pressure and postoperative pain in intraocular surgery.

Amides↗
PubMedDate not supplied

The penetration of ofloxacin into human aqueous humor given by various routes.

This study was designed to measure the concentration of ofloxacin in aqueous humor after topical, oral and intravenous administration in 50 patients undergoing cataract extraction. In Group 1, ofloxacin 0.3% eyedrops were topically instilled ten times and the aqueous humor concentration was 2.73 +/- 0.88 microg/ml. In Group 2, ofloxacin 0.3% eyedrops were topically instilled six times and the aqueous humor concentration was 0.84 +/- 0.61 microg/ml. Aqueous humor concentration 12 hours after 200 mg oral dose in Group 3, was 0.38 +/- 0.12 microg/ml. In Group 4, patients were given ofloxacin as a single intravenous 200 mg dose and the aqueous humor concentration 2 hours after the end of infusion was 0.45 +/- 0.11 microg/ml. Concentrations were determined by high performance liquid chromatography (HPLC) with fluorescence detection. There was a significant difference between Group 1 and the other groups, but not between Group 2 and Groups 3, 4. It was concluded that ofloxacin penetrates the corneal and the blood-aqueous barriers and can achieve good aqueous levels when given topically and systematically. Ofloxacin can be applied topically for external bacterial infections such as conjunctivitis and keratitis. Systematically administered ofloxacin reached higher levels than the MIC for some bacteria which cause endophthalmitis.

Administration, Oral↗
PubMedDate not supplied

Comparison of the cardiovascular effects of amineptine with those of amitriptyline and imipramine in anaesthetized rats.

In this study, two tricyclic antidepressant drugs and amineptine, administered to anaesthetized rats by intravenous bolus injection, were compared with regard to their in vivo cardiovascular effects. Amitriptyline and imipramine decreased mean arterial blood pressure and heart rate and caused conduction and rhythm changes in ECG. Amineptine, on the other hand, increased mean arterial blood pressure and caused a transient reduction of heart rate only at doses higher than those of amitriptyline and imipramine, while producing no noticeable ECG effects, even at doses 8 times higher than for the two tricyclic antidepressant drugs. The results of this study imply that amineptine, which structurally resembles tricyclic antidepressant drugs in having three rings and a side chain, has, nevertheless, a pattern of cardiovascular effects differing from that of amitriptyline and imipramine.

Amitriptyline↗