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Biomedical subjects

T Kiliç

Publications and source records attributed to T Kiliç.

17 recordsLinked to original sources
PubMed2005

Microsurgical anatomy of the lateral walls of the pituitary fossa.

BACKGROUND: The aim was to evaluate the microanatomy of the lateral wall of the pituitary fossa in cadavers. METHODS: Histological sections of sellar-parasellar specimens from 13 cadaver heads were examined. The thickness of the pituitary capsule and inferior and lateral walls of the pituitary fossa were measured, and the collagenous structure of these layers was evaluated. FINDINGS: The pituitary gland is enveloped by a tough, thin, fibrous capsule. The inferior wall of the pituitary fossa is composed of relatively thick dura (mean thickness in the 13 specimens, 171 microm). Each lateral wall of the fossa has a thin layer of dura (mean thickness in the specimens, 85 microm). The pituitary capsule and the dural layers in the lateral and inferior walls of the fossa were immunopositive for collagen types I and II. Collagen types III, IV and V were detected only in the pituitary capsule. CONCLUSIONS: Weakness of the lateral walls of the pituitary fossa and the degree to which collagen fibres in the pituitary capsule have been biochemically damaged are important factors in infiltration of the cavernous sinus by a pituitary adenoma.

Adult↗
PubMed2004

Radiosurgical treatment of cavernous sinus cavernous haemangiomas.

BACKGROUND: The objective of this report is to evaluate the effects of radiosurgery on cavernous sinus cavernous haemangiomas (CSCHs). METHOD: Five cases of CSCHs are presented in this report. One of them was diagnosed only neuroradiologically. Other patients underwent surgery and were then referred to Gamma Knife radiosurgery for residual tumours. The cohort consisted of 3 male and 2 female patients with median age of 42 (37-60). The volume of the tumours ranged between 3.8-6.5 cc. They were treated with a marginal dose of 14 to 16 Gy (mean 15 Gy). Findings. In the mean follow-up period of 32 months (6-52 months) all of the tumours decreased in size. There were no complications related to radiosurgery. CONCLUSION: Gamma Knife radiosurgery is an effective method in the treatment of CSCH, over the period of follow-up described.

Adult↗
PubMed2004

Multimodality management of 26 skull-base chordomas with 4-year mean follow-up: experience at a single institution.

OBJECTIVE: To analyze a series of patients with pathologically confirmed skull-base chordoma, and to develop an algorithm for the management of this challenging disease based on the data, our experience, and the current literature. MATERIAL AND METHODS: Between the years 1986 and 2001, 26 chordoma patients received multimodality treatment with various combinations of conventional surgery, skull-base surgical techniques, and gamma-knife surgery at the Marmara University Faculty of Medicine. A total of 57 procedures (43 tumor excision surgeries, 7 gamma-knife procedures, and 7 other operations to treat complications) were performed. The mean follow-up period was 4 years (48.5 months). Karnofsky scoring was used to follow the patients' clinical conditions, and magnetic resonance image analysis was used to measure tumor volume over time. RESULTS: Seven patients died during follow-up. Two of the deaths were due to surgical complications, four resulted from clinical deterioration related to tumor recurrence, and one was unrelated to neoplasia. The rate of tumor recurrence after the first surgical treatment was 58%. Residual tumor volume was lower in the cases in whom skull-base approaches were used as first-line management. The 19 survivors showed little change in clinical status from initial diagnosis to the most recent follow-up check. The mean follow-up time after gamma-knife treatment was 23.3 months. During this period, mean tumor volume increased 28% above the mean volume at the time of gamma-knife surgery. The mean Karnofsky score decreased by 6% during the same time frame. CONCLUSIONS: The most effective first-line treatment for chordoma patients is surgery. The findings for residual tumor volume indicated that skull-base approaches are the best surgical option, and the complication rates for these techniques are acceptable. However, it is rare that surgery ever biologically eradicates this disease, and the data showed that these chordomas almost always progress if the tumor volume at the time of diagnosis exceeds 20 cm(3). Based on our experience and the biological character of the disease, we now advocate radiosurgical treatment (gamma-knife in our case) immediately after the first-line skull-base surgery when the tumor residual volume is <30 cm(3).

Adolescent↗
PubMed2004

Relief of hemifacial spasm after radiosurgery for intracanalicular vestibular schwannoma.

Secondary hemifacial spasm due to vestibular schwannoma is very rare. This is the first reported case of hemifacial spasm responsive to gamma knife radiosurgery in a patient with an intracanalicular vestibular schwannoma. Both the resolution of the spasm as well as tumor growth control were achieved with a single session of gamma knife radiosurgery. We report a 49-year-old male patient with a 6-month history of right-sided hearing loss and hemifacial spasm. MR examination revealed an intracanalicular vestibular schwannoma. The patient was treated with radiosurgery and received 13 Gy to the 50 % isodose line. Tumor growth control was achieved and no change in the tumor volume was present at the last follow-up at 22 months. The hemifacial spasm completely resolved after one year. Surgical removal of the presumably causative mass lesion has been reported to be the sole treatment in secondary hemifacial spasm. This case report indicates that it may be responsive to gamma knife radiosurgery. Whether or not this might be a treatment option in selected refractory cases of hemifacial spasm remains to be defined.

Hemifacial Spasm↗
PubMed2004

Anterior transcallosal approach to the colloid cysts of the third ventricle: case series and review of the literature.

OBJECTIVES: To evaluate the results of the anterior transcallosal approach to the colloid cysts of the third ventricle. PATIENTS AND METHODS: A retrospective analysis of the patients operated on between 1986 and 2003 was carried out. There were 19 patients (10 female, 9 male) with a median age of 43. The main presenting symptom was headache. One of the patients presented with acromegaly due to a pituitary tumor. The size of the cysts ranged from 15 to 43 mm. An anterior transcallosal approach was used in all patients. RESULTS: The cysts were excised totally in all cases. Postoperatively no recent memory loss has been detected in any patient. One patient with hemorrhagic papil stasis experienced temporary visual worsening. In one patient with hydrocephalus a ventriculoperitoneal shunt was needed. One patient with postoperative superior frontal gyrus venous infarction had a seizure. The follow-up period was from 1 month to 13 years (mean 5.2 years). To date, there has been no recurrence so far. CONCLUSION: The anterior transcallosal approach is a safe method for the treatment of third ventricular colloid cysts.

Adolescent↗
PubMed2001

A rare cause of hyperprolactinemia: persistent trigeminal artery with stalk-section effect.

The primitive trigeminal, otic, hypoglossal, and proatlantal intersegmental arteries are fetal anastomoses between the carotid and vertebrobasilar systems. Persistent trigeminal artery (PTA) is the most frequent embryonic communication between the vertebrobasilar and carotid systems in adults. We report a case of PTA compressing the left side of the pituitary gland and stalk, in a patient with elevated blood prolactin level.

Adult↗
PubMed2001

Determining optimal MRI follow-up after transsphenoidal surgery for pituitary adenoma: scan at 24 hours postsurgery provides reliable information.

There is no agreed-upon schedule for MRI follow-up after pituitary adenoma removal via the transsphenoidal approach. Our aim was to establish a plan for MRI follow-up after pituitary surgery. Eighty pituitary adenoma cases (25 microadenomas, 30 macroadenomas that did not infiltrate the cavernous sinus, and 25 macroadenomas with cavernous sinus infiltration) were prospectively studied with MRI following tumor resection via the transsphenoidal approach. Each patient was imaged at 24 hours, at 3, 6 and 9 months, and at 1 year or more postsurgery. The parameters studied were residual tumor, synthetic packing material (Gelfoam) versus fat graft, and normal pituitary, hypophyseal stalk and optic chiasma. The size of the pituitary structure as a whole was also measured. The latter was studied quantitatively, and the findings for the rest of the parameters were evaluated qualitatively, based on the examiners' confidence in their assessment. The final MRI study, done at least 1 year postsurgery in all cases, was considered the reference MRI for all scans. MRI performed 24 hours after surgery was diagnostically accurate for residual tumor and valuable for visualizing normal sellar structures. The findings also showed that fat packing takes longer to resorb than Gelfoam, but produces no potentially confounding contrast enhancement. An algorithm based on the results is presented for postsurgical MRI assessment of pituitary adenoma patients in which the scan at 24 hours postsurgery is the major factor that determines the timing of later rechecks.

Adenoma↗
PubMed2001

Value of transcranial Doppler ultrasonography in the diagnosis and follow-up of carotid-cavernous fistulae.

The introduction of transcranial Doppler ultrasonography (TCD) has made it possible to examine blood flow characteristics in carotid-cavernous sinus fistulae (CCSF) in a noninvasive, relatively simple, and reliable way. This study investigated the usefulness of TCD in the diagnosis and follow-up of various CCSF subtypes. We found characteristic TCD findings associated with high-flow CCSF, but perhaps more importantly, found this technique to be an excellent tool also for detecting and following treatment results in low-flow CCSF. The low-flow fistulae exhibit less specific clinical signs and are harder to distinguish using the noninvasive radiological methods of computed tomography (CT) and magnetic resonance imaging (MRI). The impact of our findings on future approaches to the diagnosis and follow-up of these different types of acquired vascular shunts is also discussed. The conclusions were as follows: a) TCD parameters (blood flow velocity and pulsatility index) for CCSF are specific, and are thus valuable in the hemodynamic assessment of these lesions. b) Since dural CCSF feature more subtle hemodynamic changes and CT and MRI findings may be normal, these cases pose diagnostic challenges. In these situations, TCD reveals specific diagnostic findings and allows the examiner to determine whether cerebral angiography is indicated.

Adolescent↗
PubMed2001

Diterpenes from Sideritis argyrea.

The known ent-kaurene diterpenes 1-9 and a new ent-labdane, ent-6beta,8alpha-dihydroxylabda-13(16),14-diene (10), were isolated from the whole plant of Sideritis argyrea. Their structures were elucidated based on one- and two-dimensional NMR techniques and HRMS.

Diterpenes↗
PubMed2001

Evaluation of gestational age based on ultrasound fetal growth measurements.

Monitoring fetal growth and assessing its predictors have important place in antenatal care management. Accurate prediction of gestational age (GA) and birth weight (BW) is clinically important. Standard growth curve chosen should be evaluated to see if it satisfies the criteria for a valid assesment. In this paper, for the purpose of contributing to develop national standards and to evaluate Hadlock's standard data pertaining to 1411 fetuses were examined. Of 1411 normally growing fetuses, one measurement for AC, BPD and FL was taken by ultrasound. GA was assessed via menstrual history which is also confirmed by ultrasonography. Several variables, AC, BPD, FL, FL/AC, BPD/FL and dependent variables (GA & BW) were modelled mathematically. Percentile values, correlation coefficients were calculated and well functioning regression equations were produced for the fetal growth evaluation. Simple correlation model re-confirmed that AC, BPD and FL were well predictors of GA. Via modelling by multivariate regression analysis (adj. R2=937), GA=4.945 (95% CI: 4.661- 5.654) + .606 AC + .105 BPD + .286 FL can be estimated. It couldn't be possible establishing an appropriate equation for prediction of BW with current data. Our study is intended to draw an attention on requirement of national standards although Hadlock's standard growth curve may evaluate fetal development accurately. Forming comprehensive cohort group is under our consideration. The equation we developed (shown in the results), might be a working contribution.

Cross-Sectional Studies↗
PubMed2000

Expression of structural proteins and angiogenic factors in cerebrovascular anomalies.

OBJECTIVE: The goal of this study was to describe the expression of matrix proteins and angiogenic factors in cerebrovascular malformations. METHODS: Forty-six cerebrovascular malformations were immunohistochemically investigated with a battery of staining for five structural proteins (collagen IV, collagen III, smooth muscle actin, fibronectin, and laminin), and three angiogenic factors (vascular endothelial growth factor [VEGF], basic fibroblast growth factor [bFGF], and transforming growth factor alpha [TGFalpha]). The lesions consisted of 34 arteriovenous malformations (AVMs), 10 cavernous malformations (CMs), and 2 venous angiomas. Expression intensity for each histological layer in the abnormal vessel wall was graded and compared. RESULTS: AVM endothelia and subendothelia expressed more laminin and collagen IV than the same layers of CMs. Conversely, CMs expressed more fibronectin than AVMs. CM endothelia exhibited more prominent staining for smooth muscle actin than AVM endothelia. AVMs and CMs expressed VEGF in the endothelium and subendothelium, and TGFalpha in endothelial and perivascular layers. However, unlike AVMs, CMs expressed bFGF in the endothelium as well. The brain tissue intermingled within AVMs also expressed growth factors. Modified glial cells in the brain tissue adjacent to CMs expressed bFGF and TGFalpha, but not VEGF. Venous angiomas did not express the studied growth factors and mainly consisted of structural proteins of angiogenically mature tissue. CONCLUSION: Expression characteristics of structural proteins reveal that AVMs and CMs have different immunohistological properties. This study provides strong confirmation of previous findings of VEGF and bFGF immunoexpression in AVMs and CMs. It adds new information on TGFalpha expression in these malformations and on expression of the angiogenic factors in venous angiomas.

Actins↗
PubMed1998

Grading and hemodynamic follow-up study of arteriovenous malformations with transcranial Doppler ultrasonography.

This study presents and tests the clinical validity of a hemodynamic grading system that depends on noninvasive transcranial Doppler ultrasonographic parameters. The suggested transcranial Doppler-based grading system was compared with the Spetzler-Martin anatomic grading for prognosticative validity and clinical dependability. We concluded the following: (1) The pulsatility index was shown to be a more dependable transcranial Doppler parameter in the clinical evaluation of an arteriovenous malformation because of two reasons: preoperative pulsatility index findings inversely correlated with arteriovenous malformation volume, and the pulsatility index returned to normal values before the mean blood flow velocity did. Therefore, hemodynamic arteriovenous malformation grading can be based on the pulsatility index. (2) A transcranial Doppler-based hemodynamic arteriovenous malformation grading system correlated highly with the Spetzler-Martin grading in predicting postoperative neurologic deficits and adverse radiologic findings. (3) The presented grading system may contribute to the standardization and quantification of the hemodynamic changes during multidisciplinary management of arteriovenous malformations.

Adolescent↗
PubMed1996

A new, more dependable methodology for the use of transcranial Doppler ultrasonography in the management of subarachnoid haemorrhage.

The role of transcranial Doppler ultrasound (TCD) in clinical decision making about vasospasm due to subarachnoid haemorrhage (SAH), shows a great variation according to neurosurgical clinics. In this prospective study, a total of 143 patients, admitted to Marmara University Department of Neurosurgery between January 1991 to March 1995 and treated surgically with the diagnosis of aneurysmal SAH, were examined by TCD. Eighty of these patients fulfilled the requirements for inclusion. In order to increase clinical dependability of TCD, a new grading system is proposed and tested in comparison with the one previously used, which takes absolute flow velocities as the main parameter in grading. The new, individually based TCD grading system is proposed to minimize the pitfalls caused by proximal stenosis, wide range of normal Vm values and proximally evolving vasospasm. We concluded that: 1) The new, individually based TCD grading system has a high degree of clinical dependability. 2) Daily TCD examinations supply reliable predictive information about developing delayed ischaemic deficit (DID). If a TCD Gr II patient shows an increase of 35 cm/sec (in 24 hours) in Vm value, his probability of developing DID was found to be 60% (p < 0.05); if a TCD Gr B III patient shows the same rate of increase in Vm, his probability of developing DID was 80% (< 0.05). 3) TCD has an important clinical role in decision making about the management of SAH patients. 4) Surgical manipulation causes a reversible increase of one or two TCD-grades in the early postoperative days.

Adolescent↗
PubMed1996

Neonatal intracranial hemorrhage due to rupture of arteriovenous malformation.

Two cases of neonatal intracerebral hemorrhage secondary to rupture of arteriovenous malformation are reported and the pertinent literature is reviewed. Despite the limited number of cases, review of the literature and our results demonstrate that the outcome of surgical removal of an arteriovenous malformation in the neonatal period is not as poor as was previously believed.

Aneurysm, Ruptured↗
PubMed1995

Brucellar spondylitis mimicking lumbar disc herniation. Case report.

In this paper, a patient with brucellar spondylitis who was initially diagnosed as having a lumbar disc herniation is presented. As the disc tissue enlarges in the early stages of discitis because of the inflammatory reaction, it may compress the related root(s) mimicking a disc herniation. For this reason infectious discitis, as in our case, should be kept in mind in the differential diagnosis of the radicular symptoms caused by a disc herniation. The crucial role of magnetic resonance imaging in making the differential diagnosis of the case is especially emphasized.

Adult↗
PubMedDate not supplied

Gliosarcoma associated with neurofibromatosis type I: a case report.

Neurofibromatosis type I (NF I) is the most common hereditary syndrome predisposing to neoplasia. We report the third case in the literature, documenting the combination of gliosarcoma with NF I. The patient's son was known at our center because of a history of pleomorphic xanthoastrocytoma (PXA) with NF I. A 48-year-old man who had a number of café-au-lait spots with neurofibroma since birth presented with severe headache. Neuroradiological studies revealed a cystic tumor of the right temporal lobe of high grade nature. Surgical excision was performed and the tumor was found to be located on the surface of the temporoparietal area with cystic formation and vascular and infiltrative features. Postoperative MRI Key words: gliosarcoma, neurofibromatosis I, temporal lobe. showed no detectable contrast enhancing tissue. Immunohistochemical examination evidenced the characteristics of typical gliosarcoma. The patient received radiation therapy but five months following surgery recurrence of the tumor was diagnosed. Reoperation was performed and histopathological studies confirmed the diagnosis of gliosarcoma. We believe that the neurofibromatosis was inherited by the son with PXA from the father with gliosarcoma. The rarity of the combined occurrence of gliosarcoma and NF I, in addition to this uncommon family history, makes this case remarkable. Our findings suggest that NF I is a multifaceted disease associated with benign as well as malignant astrocytic tumors.

Brain Neoplasms↗