Biomedical subjects

M Karaçorlu

Publications and source records attributed to M Karaçorlu.

12 recordsLinked to original sources

PubMed2000

Effect of CO2, Nd:YAG, and ArF excimer lasers on dentin morphology and pulp chamber temperature: an in vitro study.

This study compared the effect of three laser systems: CO2 (10.600 nm), Nd:YAG (1.064 nm), and ArF excimer (193 nm) lasers on dentin hard tissue and on temperature increases of the pulp chamber. Sixty-six third molar teeth were used and randomly divided into three groups. A class I cavity was made to expose the dentin, and the pulp in the pulp chamber was removed via a hole bored in the cervical area. The pulp chamber was subsequently refilled with silicon grease, and a NiCr/NiSi thermocouple was inserted through the hole into the pulp chamber. The dentin surface was then lased for 30 s at the same settings (3 W, 2 mm spot size, 20 pps) with each laser. The average internal temperature increases were as follows: CO2, 37 degrees C; Nd: YAG, 28 degrees C; and ArF excimer, 1 degrees C. Scanning electron microscopy of the dentin in the occlusal cavity revealed extensive carbonization, isolated balls of recrystallized material, and the presence of smear layer at some dentinal tubule orifices for the CO2 and Nd:YAG lased teeth. Smear layer was also observed for the ArF excimer samples; however, they exhibited far less surface cavities than the others and seemed to undergo little morphological change on the dentin.

Aluminum Silicates↗

PubMed1999

Corneal iron ring after hyperopic laser-assisted in situ keratomileusis.

PURPOSE: To report a new corneal iron ring after hyperopic laser-assisted in situ keratomileusis (LASIK). METHODS: Three patients underwent hyperopic LASIK for the correction of hyperopia in both eyes. Spherical equivalent refraction of the patients ranged from +3.37 to +6.50 diopters. LASIK procedure was performed using automated corneal shaper and 193-nm argon fluoride excimer laser. RESULTS: Both eyes of the patients were noted to have a corneal iron ring located at the paracentral area at 6-7 months after surgery. The localization of iron ring corresponded with outside border of central steep zone. Twelve-month examination showed there was no change in color, shape, and density of corneal iron ring. CONCLUSIONS: Corneal topographic changes induced by hyperopic LASIK may cause corneal iron ring to develop.

Adult↗

PubMed1997

The extent of leprosy-related disabilities in Istanbul Leprosy Hospital, Turkey.

This study was carried out between January and December 1992 at the Istanbul Leprosy Hospital. Seven hundred and eleven leprosy patients were evaluated according to their age, gender and type of disease and disability according to the WHO disability grading system (1980). There were 527 males (74.2%) and 184 females (25.8%) in the group. The average age was 50.0 +/- 13.5 years and the average duration of disease was 25.9 +/- 13.2 years. Six hundred and seventy-eight patients (95.4%) were in borderline (BL) and lepromatous (LL) leprosy. The extent of disabilities was very high in 711 leprosy patients. It was found that 539 of the patients (75.8%) had eye disabilities, 511 of them (71.8%) had hand disabilities, 521 of them (73.3%) had foot disabilities. The most frequent eye, hand and foot disabilities were a decrease of vision (52.7), acute or chronic iridocyclitis (48.8%), slightly-marked corneal sensory loss (43.2%), mobile claw hand (33.3%), palmar insensitivity (16.3%), plantar ulcer (37.2%) and plantar insensitivity (19.8%). Eye deformities were the most common of the three affected areas in this study.

Female↗

PubMed1994

Retinal toxicity of intravitreally injected faeriefungin.

Faeriefungin is a new antibacterial and antifungal agent derived from a strain of Streptomyces griseus var. autotrophicus. Under anesthesia, 12 albino rabbits underwent injection in their right eyes with 400, 200, 100, 40, 20, and 10 micrograms of faeriefungin. Retinal toxicity was assessed by electroretinography and light and transmission electron microscopy. Injection of 400 micrograms resulted in severe retinal toxicity, although indirect ophthalmoscopy was unremarkable. At 200 micrograms, there was moderate toxicity. Intravitreal injection of concentrations of 100 micrograms or less produced no neuroretinal toxicity. These data suggest that faeriefungin is a potentially useful drug in the treatment of fungal or bacterial endophthalmitis.

Animals↗

PubMed1993

Scleral damage: comparison of standard and modified diathermy electrodes.

Full-thickness scleral diathermy using a standard electrode causes significant scleral damage and necrosis. Use of a modified (Jabbour's) diathermy electrode appears to cause minimal scleral damage. We evaluated the scleral changes following transscleral diathermy application using standard and modified diathermy electrodes to the peripheral retina and ciliary body. Twelve Dutch belted pigment rabbits were used in our experiment. Three eyes each were subjected to transscleral diathermy using standard and modified electrodes to produce chorioretinal scars and cyclodestruction. Eyes were examined with the slit lamp and indirect ophthalmoscope at weekly intervals for 4 weeks. Light and transmission electron microscopy was performed 1 hour after diathermy application in 4 animals and in the remaining 8 animals at 4 weeks. Chorioretinal scarring and ciliary body atrophy were successfully induced with both types of electrodes. However, scleral damage was less severe in eyes treated with the modified electrode as compared with the standard electrode.

Animals↗

PubMed1993

Perfluorooctylbromide (PFOB) as a vitreous substitute in non-human primates.

We evaluated the toxicity of perfluorooctylbromide in the primate eye as a short-term postoperative vitreous substitute. Four eyes of 4 African green monkeys underwent complete vitrectomy and vitreous replacement with 1.5-2.0 ml of PFOB. One additional animal received BSS as a control vitreous substitute in one eye. Animals were examined twice weekly for clarity and consistency of the vitreous replacement substance. Anterior segment and lenses remained clear in all eyes, although in the immediate postoperative period one eye became inflamed and had a culture-negative vitritis. The other eyes showed a minimal anticipated postoperative vitreous inflammation. Emulsification of the PFOB began within 3 days of injection and progressed up to 3 weeks, precluding fundus examination and fluorescein angiography after 2 weeks. Eyes were enucleated and light microscopy performed at 2 days, 10 days, 33 days, and 45 days. No toxic effects to the retinal cells were detectable by histological examination, but perivasculitis of retinal vessels was noted at 45 days. Indirect examination was normal up to 10 days; thereafter, the fundus view was obscured by the emulsified PFOB. Because of cellular migration into the vitreous cavity and retinal perivasculitis, observed histologically, PFOB seems most suitable for intraoperative rather than postoperative use.

Animals↗

PubMed1993

Early and early disseminated phases of Lyme disease in the rhesus monkey: a model for infection in humans.

We demonstrate that Borrelia burgdorferi infection in the rhesus monkey mimics the early and early disseminated phases of human Lyme disease. Clinical, bacteriological, immunological, and pathological signs of infection were investigated during 13 weeks after inoculation of the spirochete. Three animals were given B. burgdorferi (strain JD1) by needle inoculations, six animals were exposed to the bite of B. burgdorferi-infected Ixodes dammini ticks, and three animals were uninfected controls. B. burgdorferi could be recovered from all animals that were given the spirochete. Bacteria were detectable until week 6 postinoculation (p.i.) in blood, until week 8 p.i. in skin biopsies, and at 10 weeks p.i. in the conjunctiva of one of two animals which developed conjunctivitis. Erythema migrans (EM) appeared in one of the three animals infected by needle inoculation and in five of the six animals infected by ticks. Deep dermal perivascular lymphocytic infiltrations (characteristic of human EM) were observed in all animals showing EM clinically. Both EM and conjunctivitis were documented concomitantly with the presence of the spirochete. Lethargy, splenomegaly, and cerebrospinal fluid pleocytosis were also noted in some animals, but the direct connection of these signs with the infection was not shown. The appearance rate of immunoglobulin M and immunoglobulin G antibodies to B. burgdorferi, as well as the antigen spectra recognized, were remarkably similar to those seen in humans. Serum antibodies from infected animals were able to kill B. burgdorferi in vitro in the presence of rhesus complement. The rhesus monkey model appears to be useful for the investigation of the immunology and pathogenesis of Lyme disease and for the development of immunoprophylactic, diagnostic, and chemotherapeutic protocols.

Animals↗

PubMed1992

Retinal toxicity of intravitreal lazaroid (21-aminosteroid U75412E).

The 21-aminosteroids or lazaroids are a novel series of compounds being developed for the acute treatment of traumatic or ischemic injury of the nervous system. These compounds were specifically designed to localize within cell membranes and inhibit lipid peroxidation reactions. In this study, 21-aminosteroid U75412E was injected into the vitreous body of rabbit eyes to evaluate its suitability for intraocular injection and its toxicity on intraocular tissues. Doses ranged from 20 micrograms to 200 micrograms. Retinal toxicity was determined through light and transmission electron microscopy and electroretinography. No retinal toxicity was noted in doses of 30 micrograms and below.

Animals↗

PubMed1992

Retinal toxicity of 6-methoxypurine arabinoside (ara-M). A new selective and potent inhibitor of varicella-zoster virus.

The toxicity of a new antiviral agent, 6-methoxypurine arabinoside (ara-M), as a selective and potent inhibitor against varicella-zoster virus, was investigated after intravitreal injection in rabbit eyes. Intravitreal doses of ara-M ranging from 20 micrograms to 400 micrograms produced no retinal toxicity, as assessed by electroretinography and light and transmission electron microscopy. These data suggest a potential role for intravitreal ara-M in the antiviral treatment of varicella-zoster viral retinitis.

Animals↗

PubMed1992

Evaluation of silicone gel as a long-term vitreous substitute in non-human primates.

Two preparations of silicone gels were evaluated as long-term vitreous substitutes in the vitrectomized and lensectomized eyes of primates. Both preparations were injected in liquid form and polymerized in the vitreous cavity. There was no toxic effect on the ocular structures up to 13 months after implantation. Fundus examination and fluorescein angiography were possible through the less rigid gel, whereas the preparation with higher rigidity consistently appeared cloudy.

Animals↗

PubMedDate not supplied

Simultaneous and sequential photorefractive keratectomy.

The purpose of this study was to show the safety, effectiveness, and predictability of simultaneous bilateral as compared to sequential unilateral photorefractive keratectomy in 273 normally sighted myopic eyes. An excimer laser with a fluence of 180 mj/cm2 at a frequency of 10 Hz was used at three ablation zones (5 mm, 6 mm, and 6.5 mm). There were no significant differences between the two groups' results. Mean refraction at six months was 0.34-0.96 D in group 1 simultaneous group and 0.32-0.95 D in group 2 sequential group. At 9 months after surgery, 84% of eyes had an uncorrected visual acuity of at least 20/40. The average pain score on the first postoperative day was 2.4 for group 1 simultaneous group and 2.3 for group 2 sequential group. No serious complications occurred. Despite the short follow up, simultaneous bilateral photorefractive keratectomy appears to be an effective and safe procedure for the correction of myopia.

Adult↗

PubMedDate not supplied

Management of retinopathy of prematurity with cryotherapy.

PURPOSE: Newborns at risk for retinopathy of prematurity (ROP) should be examined 4 to 8 weeks postpartum. Various treatment modalities including cryotherapy, are proposed to ablate the retinal proliferation, when serious and progressive ROP is detected. This study stresses as main risk factors low birth weight and short gestational age as pre-disposing to ROP and the efficiency of cryotherapy as a treatment modality. METHODS: One hundred and twenty five newborns were examined before hospital discharge and after oxygen administration was terminated. Patients with suspected ROP returned for frequent follow-up visits. In patients with stage III ROP (ridge with extraretinal fibrovascular proliferation) ablation by cryotherapy was performed. RESULTS: Retinal ridge and extraretinal proliferation characteristic of stage III ROP were detected in ten newborns. All surviving stage III patients were treated with cryoablation and two of them progressed to stage IV. Regression of ROP was observed in eight of the ten treated cases. CONCLUSIONS: With properly planned screening of newborns at risk for ROP, early diagnosis and treatment are possible. Cryotherapy seems to be effective for ablation of the proliferation.

Cryotherapy↗