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Biomedical subjects

Hakki Dogan

Publications and source records attributed to Hakki Dogan.

8 recordsLinked to original sources
PubMed2006

Figure-of-eight vertical mattress suture technique for anterior flap suspension to overlying tissues in external dacryocystorhinostomy.

PURPOSE: To describe figure-of-eight vertical mattress suture technique in external dacryocystorhinostomy for a combined one-step closure of anterior mucosal flaps and overlying wound tissues and to evaluate its effectiveness on surgical outcome. DESIGN: A prospective, single surgeon, uncontrolled, interventional case series. METHODS: A total of 112 consecutive lacrimal drainage systems of 106 patients (84 women, 22 men; 100 unilateral, six bilateral) from June 2002 to January 2006 with acquired nasolacrimal duct obstruction without canalicular disease underwent external dacryocystorhinostomy with this modified technique. Relief of epiphora and anatomic patency were defined as success. Operative time and success rate were evaluated and advantages were stressed and compared with our previous reports. RESULTS: Mean age was 40.1 years (range, 6 to 75). The etiology was idiopathic in 109 patients and traumatic in three cases. Of 112 lacrimal drainage systems, epiphora was the presenting symptom in 88, combined epiphora and recurrent dacryocystitis in 15, and combined epiphora and mucocele in nine cases. Seven lacrimal drainage systems were revision cases. Mean follow-up was 26.3 months (range, 6 to 48). Success rate was 99.1% (111/112) and mean operative time was 38.2 minutes (range, 28 to 69). CONCLUSIONS: Such a modified suture technique reveals a rapid and simultaneous one-step closure of two different layers that speeds up surgical procedure; simplifies closure process as the knots are tied completely outside the wound, avoiding the disadvantages of suture tying in a small and deep area; eliminates the dead space between anterior flaps and overlying wound tissues; keeps anterior mucosal flap complex away from posterior flaps that prevents collapse back onto the anastomosis and decreases the possibility of mucosal adhesions and, therefore, fibrotic band formation with underlying tissues that may also be useful in cases with small sacs or osseous openings and in revision cases where scarring is a large concern.

Adolescent↗
PubMed2006

Color Doppler imaging of ocular hemodynamic changes in Behçet disease and uveitis patients with different etiologies.

PURPOSE: To investigate blood flow velocity changes and resistivity index values of orbital vessels in Behçet disease with or without ocular involvement, in uveitis patients with different etiologies, and in healthy volunteers. METHODS: Subjects were divided into four groups: those with ocular involvement in Behçet disease (group I), those without ocular involvement in Behçet disease (group II), uveitis patients with different etiologies (group III), and a control group (group IV). Twenty-seven eyes in group I, 14 eyes in group II, 25 eyes in group III, and 27 eyes in group IV were investigated. The blood flow in the central retinal artery (CRA), ophthalmic artery (OA), nasal posterior ciliary artery (NPCA), and the temporal posterior ciliary artery (TPCA) was measured using color Doppler ultrasonography (CDU) to determine the peak systolic velocity (PSV), end diastolic velocity (EDV), and resistivity index (RI). RESULTS: The PSV and EDV value of CRA in groups I, II, and III were found to be significantly lower than those in the control group (p < 0.05 for each). The PSV and EDV values of TPCA and NPCA in groups I, II, and III were significantly lower than those in the control group (p < 0.05 for each). Resistivity indexes of all arteries were higher in groups I, II, and III than the control group. The PSV and EDV in CRA, TPCA, and NPCA in Behçet disease patients with ocular involvement were significantly lower than all other groups (p < 0.05). CONCLUSIONS: There are significant reductions in the blood flow values of the orbital arteries in patients with Behçet disease and uveitis patients with different etiologies when compared with healthy volunteers. The decrease in blood flow values in Behçet disease is more evident in patients with ocular involvement than the patients without ocular involvement. This might be the result of occlusive vasculitis, which is frequently seen in the retinal vessels of patients with Behçet disease.

Adolescent↗
PubMed2004

Pattern VEP is a useful technique in monitoring the effectiveness of occlusion therapy in amblyopic eyes under occlusion therapy.

PURPOSE: To evaluate the effectiveness and clinical significance of pattern visual evoked potential (P-VEP) parameters on visual acuity in amblyopic patients under occlusion therapy. METHODS: A total of 34 consecutive children with anisometropic amblyopia were included in this study. All patients underwent a full initial ophthalmologic and orthoptic evaluation. P-VEP test was performed in all cases and binocular vision was tested and recorded with Worth's four-dot test and Bagolini striated glasses at each visit. Part-time occlusion therapy was performed by using adhesive patches. RESULTS: The mean (+/- SEM) cycloplegic refractive error was + 5.6 +/- 0.6 diopters (D) in the amblyopic eyes and + 1.8 +/- 0.2 D in the normal eye. The mean levels of best-corrected visual acuity were statistically differed between each measurement for occlusion therapy (for each, p < 0.05). The ratio of the patients with binocular vision increased after 6 months occlusion therapy and the difference was statistically significant (p < 0.05). In addition, P100 amplitude improved at each visit and the difference was significant when compared with baseline values (for each, p < 0.05). CONCLUSIONS: P100 amplitude of the P-VEP test parallels the improvement in subjective visual acuity in amblyopic eyes under occlusion therapy. Therefore, this test may be useful in monitoring the visual acuity in the preverbal or non-verbal patched patients.

Amblyopia↗
PubMed2003

Adenosine deaminase enzyme activity is increased and negatively correlates with catalase, superoxide dismutase and glutathione peroxidase in patients with Behçet's disease: original contributions/clinical and laboratory investigations.

AIM: Behçet's disease (BD) is an inflammatory vasculitis with immunologic, endothelial and neutrophil alterations. Adenosine deaminase (AD) is a marker of T-cell activation and is related to the production of reactive oxygen species by neutrophils with the production of NO(*), O(2)(*-), H(2)O(2) and OH(*). We reported increased tumour necrosis factor-alpha, soluble interleukin-2 receptor, interleukin-6, interleukin-8 and NO(*) in active BD. As there is a relation between cytokines, T cells and oxidative stress in inflammatory diseases, this study further evaluated: (1) plasma AD activity and its correlation with acute phase reactants; (2) thiobarbituric acid-reactive substances (TBARS) as an indicator for lipid peroxidation; and (3) antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase in patients with BD. The effect of disease activity and correlations between the measured parameters were explored. METHODS: A total of 35 active (n=17) or inactive (n=18) patients with BD (16 men, 19 women) satisfying International Study Group criteria, and 20 age-matched and sex-matched controls (nine men, 11 women) were included in this cross-sectional case-control study. AD and TBARS were measured in plasma, catalase in red blood cells (RBC), and SOD and GSHPx in both plasma and RBC in both groups. Acute phase reactants (alpha(1)-antitrypsin, alpha(2)-macroglobulin, neutrophils, erythrocyte sedimentation rate) were used to classify patients as active or inactive. RESULTS: Plasma AD (mean+/-standard error of the mean, 36.1+/-0.7 U/l) and TBARS (4.2+/-0.1 nmol/ml) levels were significantly (for each, p<0.001) higher in BD than in controls (24.1+/-0.8 U/l and 1.6+/-0.1 nmol/ml, respectively). RBC catalase activity was significantly (p<0.001) lower in BD than in controls (120.9+/-3.8 versus 160.3+/-4.1 k/g haemoglobin). SOD and GSHPx activities were significantly lower in both plasma and erythrocytes of patients with BD than in controls (plasma SOD, 442.4+/-8.6 versus 636.4+/-9.2 U/ml, p<0.001; RBC SOD, 3719.2+/-66.0 versus 4849.7+/-49.0 U/g haemoglobin, p<0.001; plasma GSHPx, 73.1+/-1.5 versus 90.6+/-2.9 U/ml, p<0.001; RBC GSHPx, 600.7+/-8.0 versus 670.6+/-10.1 U/g haemoglobin, p<0.001). Active BD patients had significantly lower antioxidant enzymes (except RBC catalase) and higher AD and TBARS levels than inactive subjects (for each, p<0.01). When considering all BD patients, a significant positive correlation was present between AD and TBARS (p<0.001) whereas both AD and TBARS were negatively correlated with antioxidant enzymes (for each, p<0.05). CONCLUSIONS: AD and lipid peroxidation are increased and associated with defective antioxidants in BD, suggesting interactions between activated T cells and neutrophil hyperfunction. Measures of pro-oxidative stress and antioxidative defence with AD activity as an indicator of T-cell activation can be considered as significant supportive diagnostic indicators, especially in active disease. In addition, strengthening the antioxidant defence may contribute to treatment modalities.

Acute-Phase Proteins↗
PubMedDate not supplied

Deep sclerectomy with various implants: an experimental and histopathologic study in a rabbit model.

BACKGROUND AND OBJECTIVE: To investigate the effectiveness of various implants used in experimental deep sclerectomy and to report tissue reactions developed to these implants histopathologically. MATERIALS AND METHODS: Forty eyes of 40 New Zealand white albino rabbits underwent deep sclerectomy with various implants. The rabbits were divided into four groups; each consisted of 10 eyes. Deep sclerectomy was performed using copolymer materials in group 1, silicone materials in group 2 and chromic catgut suture in group 3. No implants were used in the control group (group 4). Clinical and histopathological examinations were performed to investigate the effectiveness of implants. RESULTS: Mean preoperative intraocular pressure (IOP) was 14.4 +/- 1.6 mm Hg in group 1, 14.5 +/- 1.8 mm Hg in group 2, 13.8 +/- 1.5 mm Hg in group 3 and 14.5 +/- 1.2 mm Hg in group 4. The final postoperative IOPs were 10.7 +/- 0.9, 10.6 +/- 0.8, 13.5 +/- 1.0, and 14.5 +/- 1.4 mm Hg, respectively. At 2 months, the decrease in IOPs from baseline and the persistence of the filtering bleb were significantly marked in group 1 and group 2 (p < 0.001). Histopathological evaluation revealed that copolymer and silicone materials formed a smooth and regular intrascleral space. There were no foreign body reaction, tissue destruction or fibrosis in group 1 and group 2, but chromic catgut sutures caused severe fibrosis and inflammatory reaction in group 3. Mean histopathologic score of group 1, group 2, group 3 and group 4 was 0.7 +/- 0.5, 0.8 +/- 0.5, 2.4 +/- 0.6, and 0.1 +/- 0.3, respectively. CONCLUSION: Copolymer or silicone materials may increase the success rate of surgery by maintenance of a large and regular intrascleral space after deep sclerectomy and prevention of collapse of the flap.

Animals↗
PubMedDate not supplied

Plasma homocysteine and retinal artery occlusive disease: a case-control study.

BACKGROUND: Previous studies have documented that elevated plasma homocysteine is a risk factor for cardiovascular, cerebrovascular and peripheral vascular disease. In a case-control study, we sought to determine whether elevated homocysteine (HCY) is a risk factor for retinal artery occlusive disease PATIENTS AND METHODS. Study subjects consisted of 20 patients (12 male, 8 female) (mean age, 55.8; range 42-70 years) with clinical and objective evidence of retinal vascular occlusive disease and 20 age-matched control subjects (9 males, 11 females) (mean age, 55.3 years; range 50-68 years). Hyperhomocysteinemia was defined as a plasma HCY level >15 micromol/L by HPLC. We also measured concentrations of triglycerides, and total cholesterol, LDL cholesterol, and HDL cholesterol. RESULTS: The mean plasma HCY level in the patient group was 21.23+/-9.53 micromol/L (range, 8.00-43.99 micromol/L) compared with 12.59+/-4.97 micromol/L (range, 6.38 to 22.88 micromol/L) in the control group (P<0.008). There was no correlation between HCY and serum triglycerides or cholesterol levels within each group. We conclude that high plasma HCY level may be a risk factor for retinal artery occlusive disease.

Adult↗