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Biomedical subjects

M Orhan

Publications and source records attributed to M Orhan.

At least 37 records · Page 2Linked to original sources
PubMed1997

"En masse" retraction of maxillary anterior teeth with anterior headgear.

In the treatment of the first premolar extraction cases with certain techniques, incisor retraction is realized after canine distalization. In maximum anchorage cases, retraction of anterior segments require more posterior anchorage. This treatment concept is still valid, however, the difficult anchorage control is considered a major drawback. The purpose of this study is to introduce our technique for the "en masse" retraction of maxillary anterior teeth after first premolar extraction and discuss its effects. The technique consists of the application of extraoral traction on canines, followed by banding of maxillary anterior teeth, to form them as a mass. Advantages of our mechanics are as follows: (1) Anterior headgear may have the advantage of retracting anterior teeth with minimum strain on posterior anchorage. (2) The adjustability of the outer bow in relation to the premaxilla's center of resistance, provides effective desired movements. (3) Intrusion and torque control are achieved in the course of anterior segment retraction.

Adolescent↗
PubMed1997

Selçuk type headgear-timer (STHT).

The Selçuk type headgear-timer (STHT) is described and tested under laboratory conditions first and then in a controlled patient study. The timing device was compared with real time measurements for 4 months. Accuracy was determined to be absolute (100%). The STHT was determined to be independent of force variables, easy to construct, rugged, and inexpensive. In the clinical test, 10 patients were instructed to wear the extraoral appliance for 16 hours a day. After a 2-month treatment period, the timing mechanisms were introduced to the patients and a subsequent 2-month treatment period was initiated. At the end of the second period, headgear wear was increased 26%. This significant improvement in patient compliance with the STHT timing device, attached to a standard breakaway type headgear, has the likelihood of enhancing treatment results. A foolproof method of assessing actual duration of wear is now available.

Extraoral Traction Appliances↗
PubMed1997

Electron microscopy of the senile changes in lens epithelium.

Lens epithelia obtained from 37 patients who had undergone cataract surgery operation were examined by using transmission electron microscope. Their ages varied between 60-79 years and mean age was 70.2 years. Additionally, the lens epithelia of 14 patients, which were obtained in the same way were examined by using scanning electron microscope. Their ages varied between 58-78 years and mean age 70.7 years. In transmission electron microscopy, the normal appearing epithelial cells were intermingled with abnormals and the abnormal cells increased in number and in degree of abnormality with aging. The three dimensional structure of the interdigitating interlocking processes of lens cuboidal cells were visualised by using scanning electron microscope.

Aged↗
PubMed1996

Intraoperative and postoperative use of mitomycin-C in the treatment of primary pterygium.

BACKGROUND AND OBJECTIVE: The effectiveness of 0.04% mitomycin-C, either postoperatively for 2 weeks or intraoperatively as a single dose, as an adjunct in the surgical treatment of primary pterygium was evaluated. PATIENTS AND METHODS: Mitomycin-C was used in addition to the bare sclera technique in 43 eyes with pterygia. The mean follow-up time was 18.5 months for the 24 eyes in the postoperative mitomycin-C group, 10.3 months for the 19 eyes in the intraoperative mitomycin-C group, and 17.3 months for the 17 eyes in the control group (eyes that had undergone surgical excision only). RESULTS: The recurrence rate was 4.2% with postoperative administration, 5.3% with intraoperative application, and 41.2% in the control group. There was a significant reduction in recurrence rates for both the postoperative and the intraoperative mitomycin-C groups compared with the control group (P = .005 and P = .01, respectively). However, recurrence rates were not statistically different according to the type of application. No serious side effect occurred during the follow-up period. CONCLUSION: Topical mitomycin-C, either intraoperatively or postoperatively, as an adjunct decreases the recurrence rate of primary pterygium. Intraoperative application seems advantageous because it decreases the symptomatic side effects and restricts the inappropriate use by the patient.

Administration, Topical↗
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

Evaluation of retinoic acid ophthalmic emulsion in dry eye.

PURPOSE: An oil in water emulsion of 0.01% all-trans-retinoic acid (tretinoin) was prepared and clinically evaluated in dry eye patients. METHODS: The ophthalmic emulsion consisted of 10% of arachis oil and 90% of the hydrogel of Carbopol 940. To evaluate retinoic acid emulsion clinically, a placebo-controlled, open-labeled, randomized study was performed with 22 dry-eye patients. Symptoms were recorded before and after the treatments. The Schirmer I test, measurement of tear film break-up time (BUT), rose Bengal and fluorescein staining of cornea and conjunctiva, and mucus fern test were done. RESULTS: Retinoic acid did not improve the dryness, photophobia and foreign body sensation more than placebo. Schirmer test and BUT were significantly improved by retinoic acid treatment. Corneal and conjunctival epithelium maintained their characteristics during the use of retinoic acid, as indicated by rose Bengal and fluorescein staining. CONCLUSIONS: Ophthalmic emulsion of retinoic acid can be suggested as a promising approach for the treatment of dry eye.

Adult↗
PubMedDate not supplied

Ocular ferning during the menstrual cycle in healthy women.

PURPOSE: The aim of the study is to investigate whether tear ferning patterns change during different phases of the menstrual cycle. METHODS: The tear ferning test was performed on twelve normal women of childbearing age at three day intervals throughout one complete menstrual cycle. Serum hormone levels (progesterone, estrogen, testosterone) were measured. RESULTS: Eight women showed type I ferning, and the other four had type II ferning initially. These patterns did not change during the menstrual cycle. Serum hormone levels were all in the normal range. Since no change in ferning pattern was detected during the menstrual cycle, the ferning test can be done at any time in women. CONCLUSIONS: This study showed no effect of different menstrual cycle phases on tear ferning patterns.

Adult↗
PubMedDate not supplied

Corneal topographical study of the effect of lacrimal punctum occlusion on corneal surface regularity in dry eye patients.

PURPOSE: To compare topographic indices of surface regularity in dry eye patients and in normal subjects (controls) and to investigate the short-term effect of lacrimal punctal plugs on these indices in dry eye patients. METHODS: The surface regularity index (SRI) and surface asymmetry index (SAI) of the TMS-2 corneal topographic modelling system were used to evaluate corneal surface regularity in 20 eyes of 10 dry eye patients before and after the insertion of Herrick silicon lacrimal plugs (Lacrimedics, Rialto, CA, USA) and in 24 eyes of 12 normal subjects as controls. RESULTS: SRI and SAI were significantly lower in controls than dry eye patients (p=0.00). Median SRI was 1.72 in dry eye patients before punctal occlusion and 0.525 in the control group. Median SAI was 1.305 in dry eye patients and 0.240 in controls. After lacrimal punctal occlusion, Schirmer test results and fluorescein breakup time increased in nine patients and remained the same in one patient. After occlusion, the SRI decreased in 9 eyes, and increased in 11 (p=0.970); SAI decreased in 13 eyes and increased in 7 (p=0.135). CONCLUSIONS: No significant change in topographic indices of corneal surface irregularity could be detected in severe dry eye patients with lacrimal punctal plugs in the short-term follow-up.

Biocompatible Materials↗
PubMedDate not supplied

Conventional or endoscopic probing for congenital nasolacrimal duct obstruction.

PURPOSE: To compare conventional and endoscopic probing for congenital nasolacrimal duct obstruction in infants. METHODS: Conventional probing was performed in 22 eyes of 18 patients, age range 7-14 months (mean 11.4 months). Probing was done with intranasal endoscopic visualization in 18 eyes of 14 patients, age range 7-13 months (mean 11.2 months). All were primary probing cases. RESULTS: After conventional probing 2 of the 22 cases required reprobing. After endoscopic probing only 1 of the 18 cases required reprobing. CONCLUSIONS: In most cases of congenital nasolacrimal duct obstruction endoscopy is not required; however, in failed cases direct visualization of the inferior meatus with endoscopic guidance may be helpful.

Dacryocystorhinostomy↗
PubMedDate not supplied

Lacrimal function and ocular complications in patients treated with systemic isotretinoin.

PURPOSE: To evaluate the effect on lacrimal function and ocular complications in patients with severe acne vulgaris during systemic treatment with 13-cis-retinoic acid (isotretinoin). METHODS: Forty patients with acne vulgaris were treated with systemic isotretinoin at dosages of 0.5-1 mg/kg per day for two months. Full ophthalmologic examination, Schirmer I test, fluorescein break-up (BUT) and microbiological investigations of the conjunctival flora were done before, during the second month and at least one month after the end of the treatment. RESULTS: The average Schirmer values before and after the treatment were 21.6 mm/5 minutes (SD +/- 7.01) and 18.48 mm/5 minutes (SD +/- 7.87) respectively. After the treatment BUT was less than 10 seconds in 50% of the patients and 55% had blepharitis. Subjective symptoms like dryness, itching and contact lens intolerance occurred in 42.5% and colonization of the conjunctiva by Staphylococcus aureus increased significantly during treatment (p= 0.031). All abnormal findings disappeared one month after the cessation of treatment. DISCUSSION: Isotretinoin causes signs and symptoms of dry eye, probably by reducing meibomian gland function, but ocular complications are generally not serious when low doses are used for a limited time, and are reversible after discontinuation.

Acne Vulgaris↗
PubMedDate not supplied

Scanning laser polarimetric analysis of retinal nerve fiber layer thickness in Turkish patients with glaucoma and ocular hypertension.

PURPOSE: To assess the thickness of the retinal nerve fiber layer (RNFL) in patients with different stages of glaucoma, in comparison with ocular hypertensive (OHT) and healthy subjects in a Turkish population. METHODS: Scanning laser polarimetry was done with a GDx Nerve Fiber Analyzer (NFA, GDx version, 1.0.08) on 270 eyes with glaucoma, 52 OHT eyes, and 81 normal eyes. The eyes were classified as having early (146 eyes), moderate (66 eyes) and severe (58 eyes) glaucoma based on the Humphrey Visual Field indices. We compared 14 NFA parameters by analysis of variance (ANOVA) and Scheffe multiple comparison analysis. Receiver operator characteristic curves (ROC) and Fisher linear discriminant analysis (LDF) were used to measure the sensitivity and specificity of the NFA parameters. RESULTS: Except for symmetry, all NFA parameters showed significant differences between the groups (p<0.05). The eyes with glaucoma had significantly thinner RNFL than healthy eyes (p<0.01). The RNFL retardation measurements of OHT eyes were lower than controls, but higher than the early glaucoma group. The sensitivity and specificity of the GDx System were 87% and 72.8%, respectively. Applying LDF, the group with the highest sensitivity and specificity (85.9% and 74.1%) was determined as inferior ratio, superior/nasal ratio, superior maximum and the Number. CONCLUSIONS: Assessment of RNFL thickness with scanning laser polarimetry can distinguish glaucoma, OHT and normal subjects with relatively high sensitivity and specificity.

Adult↗
PubMedDate not supplied

Corneal neovascularization possibly associated with latanoprost therapy.

PURPOSE: To report a case of corneal neovascularization possibly associated with latanoprost therapy. METHODS CASE REPORT: A 67-year-old man developed a progressive stromal corneal neovascularization in his right eye within eight months of a corneal trauma. At admission, he was receiving latanoprost 0.005% therapy. His topical medications were rearranged: latanoprost was replaced with carteolol hydrochloride 1% twice daily bilaterally and prednisolone acetate 1% was added twice daily in the right eye. RESULTS: One month later, he presented regression of the corneal neovascularization and an increase in visual acuity. CONCLUSIONS: Latanoprost, an arachidonic acid derivative, could have directly or indirectly stimulated the corneal neovascularization in this patient with a history of nonpenetrating corneal trauma.

Administration, Topical↗
PubMedDate not supplied

Relationship between short wavelength perimetry and central corneal thickness values in ocular hypertensive subjects.

PURPOSE: To evaluate the results of short wavelength perimetry (SWAP) of ocular hypertensive (OHT) patients and correlate these findings with central corneal thickness (CCT) measurements. METHODS: Thirty-seven OHT patients with a mean age of 50.2+/-8.2 (SD) years and 30 control subjects with a mean age of 50.3+/-8.5 (SD) years were included in this study. A questionnaire was applied to patients to evaluate the demographic risk factors that may predict glaucoma development. After a detailed ophthalmologic examination, achromatic and short wavelength perimetries and ultrasonic pachymetry were performed and the results were compared between the two groups with Student t test and Mann-Whitney U test. A p value<0.05 is considered as statistically significant. RESULTS: Mean CCT was higher in the OHT group (right eye; 558.13+/-28.39 microm and left eye; 558.94+/-27.30 microm) when compared with the control subjects (524.66+/-30.53 microm and 525.86+/-30.46 microm, respectively) (p<0.01). A significant positive correlation was found between CCT measurements and intraocular pressure (r=0.5, p<0.001). Four right eyes (10.8%) and five left eyes (13.5%) of OHT patients had defects in SWAP. OHT patients with SWAP abnormalities had significantly lower CCT measurements in right (527.25+/-17.34 microm) and left eye (528.80+/-13.60 microm) when compared with OHT patients without SWAP defects (561.87+/-27.29 microm and 563.65+/-25.92 microm, respectively) (p<0.05). Significant correlations were found between CCT and SWAP MD, PSD, and CPSD (p<0.05). CONCLUSIONS: OHT patients with SWAP abnormalities had significantly lower CCT measurements than those without. CCT is considered as a risk factor for the development of glaucomatous damage in OHT patients.

Cornea↗
PubMedDate not supplied

Lacrimal sac dacryolith: a study wit atomic absorption spectrophotometry and scanning electron microscopy.

Dacryoliths are uncommon causes of partial or complete obstruction of the nasolacrimal drainage apparatus. We report our findings of a dacryolith that we studied by culture, light microscopy, atomic absorption spectrophotometry, and scanning electron microscopy. Although no fungi were recovered by culturing, hyphae-like structures were observed. No inorganic material was detected by atomic absorption spectrophotometry. Scanning electron microscopy of ultrastructure showed the stone was composed of lobes and lobules built on an amorphous core material.

Calculi↗
PubMedDate not supplied

Expression of p53 protein in pterygium.

PURPOSE: The pathogenesis of pterygium is still not completely understood and many environmental factors, including ultraviolet (UV) radiation, play an important role in its etiology. Chronic exposure to UV radiation causes mutations in the p53 tumor suppressor gene, eventually leading to tumor formation. We analyzed the immunohistochemical expression of p53 proteins in pterygial tissues to determine the role of the p53 tumor suppressor gene in the development of pterygium. METHODS: Pterygial specimens were studied immunohistochemically using antibodies against p53 protein. RESULTS: Out of 38 specimens studied, 35 (92.1%) had conjunctival epithelial cells without p53 specific nuclear staining. Only three specimens (7.9%) had a few p53 stained cells. The role of UV radiation in the pathogenesis of pterygium is supported by epidemiological, geographical and microscopic findings. However, our results are not consistent with these data on a genetic basis. CONCLUSIONS: We conclude that defective p53 tumor suppressor gene function seems to have no role in the pathogenesis of pterygium.

Adult↗