Biomedical subjects

T Kiriş

Publications and source records attributed to T Kiriş.

8 recordsLinked to original sources

PubMed2000

Recent experience with Moyamoya disease in Turkey.

A series of moyamoya patients is presented. Angiographic findings, outcome of revascularization surgery and a young case with moyamoya disease and hyperphosphatemia are reported. Thirteen patients (6 males and 7 females; age range 2-50 years) were included in the study group. Findings of the patients at presentation were intracranial haemorrhage in two adult cases and sequelae of cerebral ischemia in the rest of the group. One young girl had hyperphosphataemia. Angiography showed distal internal carotid or proximal anterior and middle cerebral artery stenosis, unique collaterals, microaneurysm of the posterior lateral choroidal artery and flow-related changes in the posterior circulation. In 3 patients, encephalo-duro-arterio-synangiosis (EDAS) and burrholes were performed at surgery. Follow-up angiograms of these patients showed revascularization. Moyamoya, a rare but potentially devastating disease, must be addressed as a cause of haemorrhagic and ischaemic cerebral events.

Adolescent↗

PubMed2000

Superoxide dismutase activity and the effects of NBQX and CPP on lipid peroxidation in experimental spinal cord injury.

The endogenous activity of the neuroprotective enzyme superoxide dismutase (SOD) and the amount of lipid peroxidation in the early phase of experimental spinal cord injury, together with the effects of N-methyl-D-aspartate (NMDA) antagonist CPP and non-NMDA antagonist NBQX on lipid peroxidation were evaluated. The clip compression model was used for the production of a standardized spinal cord trauma. SOD activity and malondialdehyde (MDA) levels--as an indicator of lipid peroxidation--were determined in the injured segment of the spinal cord 30 and 60 min after injury. SOD activity did not change in this period, whereas MDA levels at 30 and 60 min after trauma were significantly elevated. Intrathecal administration of CPP or NBQX 15 min after injury produced statistically significant reductions in MDA elevation 60 min after injury. NBQX was found to be more effective than CPP. These results demonstrated that intrathecal local application of excitatory amino acid receptor antagonists can protect the spinal cord from secondary damage caused by the generation of lipid peroxides in experimental spinal cord injury.

Animals↗

PubMed1999

Superoxide dismutase activity and the effect of N-methyl-D-aspartate antagonists on lipid peroxidation in the early phase of cold injury.

Free radicals, lipid peroxidation and excitatory amino acids have been implicated in the secondary mechanisms of traumatic brain injury. We used the cold injury model in rats to assess the endogenous activity of the protective enzyme superoxide dismutase (SOD) and the lipid peroxidation level in the contused tissue at an early phase of injury. Furthermore, we treated the rats with two different N-methyl-D-aspartate receptor antagonists, namely MK-801 and CPP, and evaluated their effect on lipid peroxidation in the contused tissue. Rats were divided into four groups: sham, control, treatment 1 and treatment 2 groups (n= 16 for each group). Thirty and 60 min after craniectomy or injury, tissue samples were removed. SOD activity didn't change in this period. However, lipid peroxidation in terms of malondialdehyde (MDA) amount showed a significant increase at 60 min. Fifteen minutes after injury, MK-801 (1 mg/kg), CPP (10 mg/kg) or saline (1 ml) were applied intraperitoneally in treatment 1, treatment 2 and the control groups. Treatment with MK-801 attenuated MDA levels, whereas treatment with CPP did not. The protective effect of MK-801 achieved statistical significance. These results demonstrate that SOD activity does not change in the early period of cold injury. Moreover, these results show that lipid peroxidation increases after 60 min of cold injury, and treatment with MK-801 15 min after injury can prevent this elevation.

Animals↗

PubMed1999

Protective effect of the N-methyl-D-aspartate receptor antagonists, MK-801 and CPP on cold-induced brain oedema.

Cold injury model in rat was used to determine the effect of treatment with the competitive NMDA antagonists CPP and the non-competitive NMDA antagonist MK-801 in cerebral oedema. MK-801 was applied in doses of 1 mg/kg and CPP of 10 mg/kg, 15 min. after injury. Control animals received 1 ml saline at the same time interval after injury. Tissue samples from the core and periphery of the lesion of the injured hemisphere and from the symmetrical location of the undamaged contralateral hemisphere were removed 24 hours after injury. Blood brain barrier permeability, brain water content and tissue specific gravity values were determined. MK-801 was found beneficial for reducing the oedema and restore the blood brain barrier permeability at the penumbral zone of the lesion, whereas both MK-801 and CPP were found ineffective for prevention of oedema accumulation at the core of the lesion.

Analysis of Variance↗

PubMed1999

Reversal of cerebral vasospasm by the nitric oxide donor SNAP in an experimental model of subarachnoid haemorrhage.

The constant release of nitric oxide (NO) is essential to maintain basal cerebrovascular tone. Oxyhaemoglobin, liberated by lysis of red blood cells after subarachnoid haemorrhage binds NO and prevents its entry into vascular smooth muscle cells. While endothelium-dependent vasoconstriction is preserved, decreased levels of NO inhibit endothelium-dependent relaxation and may cause vasospasm. S-nitrosothiols are potent vasodilators and precursors of NO. The authors' aim was to determine whether S-nitroso-N-acetylpenicillamine (SNAP), a stable S-nitrosothiol compound, could reverse vasospasm in an experimental vasospasm model in rabbit. Experimental subarachnoid haemorrhage (SAH) was induced in 37 New Zealand white rabbits. The animals were divided into four groups. Control (no SAH), SAH only, SAH plus saline and SAH plus SNAP. SNAP (15 micrograms/kg/min) or 0.09% saline (equal volume) was infused 46 hours after induction of SAH. All animals were killed by perfusion fixation 48 hours after SAH occurred. Basilar arteries were removed, sectioned and their cross sectional areas were evaluated in a blind manner, by light microscopy and by using computer assisted morphometry. Experimental SAH elicited vasospasm in all animals of SAH only and SAH plus saline group. In animals treated with SNAP, arterial narrowing was markedly attenuated without producing systemic hypotension. This widening achieved statistical significance when compared to the arteries of the SAH only and SAH plus saline group (p < 0.01). This study indicates that the NO donor SNAP is a potentially useful drug to reverse cerebral vasospasm due to SAH.

Animals↗

PubMed1998

Orbitozygomatic craniotomy. Technical note.

The orbitozygomatic approach provides wide, multidirectional access to the anterior and middle cranial fossae, as well as to the upper third of the posterior fossa and clivus. The authors describe technical details of the surgical approach as it has evolved over 3.5 years of experience in 83 consecutive cases. This modified technique eliminates the need for bone reconstruction of the orbital walls to prevent enophthalmos and minimizes the risk of injury to the frontal branch of the facial nerve. At a follow-up evaluation after a period averaging 14 months, all patients were pleased with the cosmetic results of this approach.

Brain Neoplasms↗

PubMed1994

Bromocriptine-induced cerebrospinal fluid fistula in patients with macroprolactinomas: report of three cases and a review of the literature.

Bromocriptine therapy for macroprolactinoma induced cerebrospinal fluid (CSF) rhinorrhea in three patients. The tumor had extended well beyond the sella turcica and caused bony erosion in all the cases. All three patients responded to bromocriptine therapy rapidly. CSF fistula occurred concomitantly with the reduction of tumor size and caused meningitis in two of the patients. Withdrawal of bromocriptine resulted in cessation of the leakage. One of the patients underwent transsphenoidal repair. Two patients refused surgery. This potentially lethal complication encountered in these three cases demonstrates the need for close supervision of macroprolactinoma patients with skull base erosion placed under bromocriptine therapy.

Adult↗

PubMed1993

A high-position basilar top aneurysm approached via third ventricle: case report.

The authors report a subfrontal transventricular approach to a high-position basilar top aneurysm considered to be inaccessible by conventional pterional or subtemporal techniques. This special technique may be preferred in the case where a megadolichobasilar artery coexists with such an aneurysm as it has the advantage of protecting the brain from the detrimental effects of strong retraction.

Adult↗