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Biomedical subjects

Olgun Kontaş

Publications and source records attributed to Olgun Kontaş.

10 recordsLinked to original sources

Torticollis secondary to posterior fossa and cervical spinal cord tumors: report of five cases and literature review.

Torticollis is either congenital or acquired in childhood. Acquired torticollis is not a diagnosis but rather a sign of an underlying disorder. The causes of acquired torticollis include ligamentous, muscular, osseous, ocular, psychiatric, and neurologic disorders and may be a symptom of significant abnormalities of the spinal cord and brain, such as spinal syrinx or central nervous system neoplasia. Torticollis is rarely considered to be an initial clinical presentation of posterior fossa and cervical spinal cord tumors. We report five cases of pediatric tumors with torticollis at the onset: an astrocytoma originating from the medulla oblongata, another presumptive astrocytoma of the spinal cord located between C1 and C6 cervical vertebrae (not operated), an ependymoma located throughout the whole cervical spinal cord extending into the bulbomedullary junction, an astrocytoma originating from the bulbus and extending into the posterior fossa, and another case of a eosinophilic granuloma located extradurally through the anterior and posterior portions of the vertebral bodies from C3 to C7 producing the collapse of the sixth cervical vertebra. All five cases were seen in children, aged between 3 and 12 years. All these cases reflect the misinterpretation of this neurological sign and the lack of association with the possibility of spinal or posterior fossa tumor. This delay in the diagnosis of these diseases led to progressive neurological deterioration and to the increase in the tumor size, which made surgical intervention difficult and the prognosis unfavorable. Although torticollis secondary to tumors is rarely seen, it is necessary to be kept in mind in the differential diagnosis.

Astrocytoma↗

Neonatal hepatitis in 2 siblings with Seckel syndrome.

Seckel syndrome was described as the prototype of the primordial bird-head type of dwarfism. We report 2 cases of Seckel syndrome in siblings. Both cases showed peculiar phenotypic features. Autopsy was performed and microscopic examination of the livers displayed histologic features of neonatal hepatitis. In addition, our younger patient had central nervous system anomalies such as agenesis of corpus callosum, cerebral cyst, and primitive convolutional pattern. No previous reports of liver disease exist in patients with Seckel syndrome. The pathologic findings of such an unusual association and a review of literature are presented.

Abnormalities, Multiple↗

Effects of prenatal flutamide on testicular development, androgen production and fertility in rats.

INTRODUCTION: To investigate the effects of blocking prenatal androgen with the anti-androgen flutamide on testicular weight (TW), seminiferous tubular diameter (STD), testicular biopsy score (TBS), testicular testosterone (TT), and fertility. MATERIALS AND METHODS: Ten pregnant Wistar albino rats were injected with flutamide (100 mg/kg) on gestational days 16 and 19. Rats injected with the solvent were used as controls. Male pups from these dams were evaluated for testicular descent on postnatal day 22. The ability of each male to produce offspring was tested when the animals were aged 130 days. The rats were killed when 180 days old, and the testes were removed. RESULTS: Sixteen of the 24 male rats (66.6%) exhibited cryptorchidism (6 unilateral, 10 bilateral) in the flutamide-treated group. Three of the rats with normally descended testicles were fertile, but none of the cryptorchid rats was fertile in flutamide-treated group. The average TW, mean STD, TBS and TT levels of the flutamide-treated rats was significantly lower than in the solvent-injected rats. However, there was no significant difference in these values between descended and undescended testes in flutamide-treated rats. CONCLUSION: Blocking of prenatal androgen with flutamide interferes with testicular development by inhibiting testicular descent, and also effects testicular morphology and function in both the descended and undescended testes of rats.

Androgen Antagonists↗

Treatment of nevoid hyperkeratosis of the nipple and areola using a radiofrequency surgical unit.

BACKGROUND: Nevoid hyperkeratosis of the nipple and areola (NHNA) is a rare condition of unknown etiology. Verrucous thickening and pigmentation of the nipple and areola are the main features of the condition. Different therapeutic options, both medical and surgical, have been described. OBJECTIVE: To use a radiofrequency surgical unit to treat an NHNA case, which was unresponsive to keratolytic therapy. MATERIALS AND METHODS: The lesions of the nipple and areolas were excised tangentially with a diamond-shaped electrode of a radiofrequency surgical unit under local anesthesia. RESULTS: The patient had a good cosmetic appearance after the treatment, and there was no recurrence at the ninth postoperative month. CONCLUSION: Radiofrequency for tangential excision in the treatment of NHNA lesions that have not responded to medical therapy can be an alternative surgical method.

Adult↗

Previous injuries or scars as risk factors for the development of basal cell carcinoma.

Basal cell carcinoma (BCC) is the most common malignant tumour in humans and most occur in elderly people. The pathogenesis of BCC is directly related to exposure to ultraviolet radiation in sunlight, but trauma is also mentioned occasionally. As well as one published series, several single cases have been reported. Our aim in the present study was to assess any possible relation between the development of BCC and trauma in a series of 92 patients, 12 of whom (13%) gave a history of previous injury. These lesions either developed directly after a sharp or blunt injury or in the scar tissue that had resulted from previous surgical incisions, burns, or dog bites. The male:female ratio was higher in the injured group (10:2) than in the uninjured group (44:36), but not significantly so (p = 0.11). Morphoea-like basal cell carcinomas were more common in the injured group (n = 91) (p = 0.06). We conclude that trauma might be considered as another aetiological agent for BCC.

Adult↗

Effect of gestational nicotine treatment on newborn rat retina: a histopathological and morphometric analysis.

BACKGROUND: Smoking is a significant risk factor in several debilitating and fatal diseases. It has been implicated in bilateral tobacco-toxic and Leber's hereditary optic neuropathies. Although it has been demonstrated that smoking has a cumulative effect on retinal and optic nerve functions and causes diffuse and localised retinal sensitivity decrease in healthy chronic heavy smokers, the affected retinal layer has not been identified and there is no experimental study investigating the effect of nicotine exposure during gestation on the newborn rat retina. PURPOSE: This experimental investigation evaluated histologically the influence in vivo of maternal nicotine treatment during pregnancy on the newborn rat retina. Different dosages of the test compound simulated the range of low, moderate, and heavy smokers in humans. METHODS: Experimentally naive, adult female Wistar-albino rats weighing 200-250 g were mated with adult male rats over 2 days for copulation in the proportion of two females for every male animal. After confirming pregnancy with vaginal smear method, 40 gravid rats (dams) were then randomly assigned into four equal groups (three experimental and one control; n = 10 in each). On day 9 of gestation, groups 1, 2, and 3 experimental dams were treated with intraperitoneal (i.p.) (-)-nicotine tartrate at doses of 0.5, 1, and 2 mg kg body weight-1 day-1, respectively during pregnancy from gestational day 9-21. Group 4 control dams were given i.p. saline solution daily for the same period. After normal delivery, the newborn litters were sacrificed at postnatal day 1 or day 30. The eyes were enucleated for histopathologic and morphometric analysis of the retinas. Nicotine-induced neuronal changes were measured by morphometric analyses on cell counts of ganglion cell layer (linear cell density in number per unit length of retina) and thickness of the various retinal layers. RESULTS: The litters in control group 4, and experimental groups 1 and 2 had normal retinal findings. On the other hand, morphometric analysis of retinal sections in experimental group 3 eyes demonstrated a 20.7% decrease in the number of surviving ganglion cells (40.7 +/- 2.0) compared with controls (51.3 +/- 1.1; p < 0.001). The thickness of whole retina (126.6 +/- 5.4 microm) was also reduced by 13.5% compared with controls (146.3 +/- 4.5 microm; p = 0.007). The main site of retinal atrophy was the inner plexiform layer (30.1 +/- 1.6 microm vs 43.5 +/- 1.3 microm; p < 0.001) with almost no change in the other retinal layers. CONCLUSIONS: Gestational nicotine treatment induces marked changes in the organisation of the developing retina in newborn rats histopathologically. Quantitative morphometric analysis clearly demonstrated that the two most affected structures were the retinal ganglion cells and the inner plexiform layer, both of which are supplied by central retinal artery.

Animals↗

Serum inhibin B levels reflect contralateral testicular damage following unilateral testicular trauma.

INTRODUCTION: The aim of this study was to evaluate contralateral testicular damage (CTD) following unilateral blunt testicular trauma (BTT) and testicular capsule laceration (TCL) by the serum inhibin B level which is an accepted marker of spermatogenesis. METHODS: Fifty peripubertal male Wistar albino rats were divided into 5 groups each containing 10 rats. Group 1 was the control group. Group 2 was the BTT group in which the right testicle was placed on a firm surface and a metal rod weighing 215 g was dropped onto the testicle from a height of 5.5 cm. Group 3 was the TCL group in which right testicular tunica albuginea was lacerated using the needle of 4/0 silk suture. Group 4 had right orchiectomy initially. Group 5 was the sham group. In all groups, 3-ml blood samples were taken and bilateral orchiectomies were performed 6 weeks after initial manipulations. RESULTS: Groups 2 and 3 had decreased inhibin B levels (p < 0.001), although the orchiectomy group had normal levels. Histological analyses showed lower Johnsen scores for both trauma groups in the ipsilateral and contralateral testes (p < 0.05). CONCLUSIONS: Serum inhibin B levels decrease following unilateral testicular trauma reflecting CTD.

Animals↗

Determination of nontoxic concentrations of piperacillin/tazobactam for intravitreal application. An electroretinographic, histopathologic and morphometric analysis.

BACKGROUND: To investigate the highest nontoxic intravitreal dose of piperacillin/tazobactam in rabbits. MATERIAL AND METHODS: Forty New Zealand white albino rabbits were used in this study. The rabbits were divided into four equal groups (10 rabbits in each) and the right eyes were treated with 0.1 ml intravitreal injections of 1,000 microg piperacillin/tazobactam in group 1, 500 microg in group 2, 250 microg in group 3, and 100 microg in group 4. The left eyes served as controls and were injected with 0.1 ml of saline solution. Ganzfeld electroretinogram (ERG) was performed on all eyes before and after 4 weeks of intravitreal injections. Then, the rabbits were killed and the eyes were enucleated for histopathological evaluation of the retina. Retinal sections were evaluated by morphometric analyses on cell counts of ganglion cell layer and thickness of the various retinal layers. RESULTS: Baseline ERGs were similar among the groups (p > 0.05). After 4 weeks of injection, there were a reduction of the b-wave amplitude and extension of the b-wave implicit time in photopic and scotopic ERGs in group 1 and group 2 when compared with controls (for each, p < 0.001). Intravitreal injection of 100 and 250 microg piperacillin/tazobactam did not cause any deterioration of the b-wave of ERGs throughout the follow-up period of 4 weeks (for each, p > 0.05). After morphometric analysis of retinal sections in all groups, there were no statistically significant differences in the mean number of surviving ganglion cells, thickness of the whole retina and the inner plexiform layer compared with controls (p > 0.05). CONCLUSION: 250 microg/0.1 ml piperacillin/tazobactam is the highest nontoxic dose to the normal retinas of adult albino rabbits as intravitreal injection. Piperacillin/tazobactam may be a new, potentially important drug in the treatment of endophthalmitis as it has a broad antimicrobial spectrum.

Animals↗

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↗