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Biomedical subjects

M Necmettin Pamir

Publications and source records attributed to M Necmettin Pamir.

At least 19 recordsLinked to original sources
PubMed2006

Superficial siderosis due to papillary glioneuronal tumor.

Superficial siderosis of the central nervous system is a rare, progressive, irreversible and debilitating neurological disease characterized by the deposition of haemosiderin in the leptomeninges and the subpial layers of the brain and spinal cord. The main clinical findings are progressive bilateral sensorineural hearing loss, cerebellar ataxia and pyramidal tract signs. The present report describes a 49-year-old woman who presented with intermittent headache of 5 years duration. The pain had become more severe in the previous 6 months. Neurological examination revealed nothing abnormal. Computed tomography showed a cystic mass with apparent internal haemorrhage in the right frontal lobe and T(2)-weighted magnetic resonance imaging showed material of low signal intensity coating the entire surface of the brain. The mass was completely excised via craniotomy. A histopathological study identified the mass as a papillary glioneuronal tumour. The patient recovered well and is still neurologically normal 1 year later. This is the first documented case of superficial siderosis caused by this type of tumour.

Brain Neoplasms↗
PubMed2006

Analysis of radiological features relative to histopathology in 42 skull-base chordomas and chondrosarcomas.

Chordomas and chondrosarcomas are malignant tumors that are reported to have similar clinical presentations and radiological features but different behaviors and outcomes. The aim of this retrospective study was to determine whether specific radiological features of skull-base chordomas or chondrosarcomas are correlated with histopathology, and thus allow preoperative diagnosis. The study involved 32 classic chordomas, 6 chondroid chordomas and 4 chondrosarcomas (42 tumors total). For each case, tumor size and extent, the detailed anatomy involved, and magnetic resonance imaging and computed tomography findings were analyzed. Tumor extent was assessed using a novel method that assessed presence/absence in 18 defined skull-base zones. The chondrosarcomas presented significantly earlier in life than the chordomas (means, 20.5 years versus 36 years, respectively). At time of diagnosis, the median tumor volume was 23 cm(3) (range, 1.2-78.8 cm(3)) and the mean tumor extent was 6.7+/-2.9 zones. There were no differences between chordomas and chondrosarcomas, or between the two chordoma subgroups, with respect to lesion volume or extent. Comparison of other imaging findings revealed no features that were diagnostic for either chordoma or chondrosarcoma. The data support previous claims that chondrosarcomas present earlier in life than chordomas, but this finding is not diagnostic. There is wide variation in the extent of skull-base chordomas and chondrosarcomas, and in the specific anatomical structures these tumors involve. None of the MRI or CT features of these tumors appear to be useful for differentiating chordomas from chondrosarcomas preoperatively. For surgical planning, specific, area-oriented definition of tumor extent might provide more useful information than tumor-type classification schemes.

Adolescent↗
PubMed2006

Non-meningeal tumours of the cavernous sinus: a surgical analysis.

The popularisation of cavernous sinus approaches and subsequent experience has shaped our treatment paradigms for cavernous sinus meningiomas. However, pathologies in this region are diverse and each one requires individual consideration. The purpose of this study was first to analyse, define and summarise the individual characteristics of different non-meningeal tumours of the cavernous sinus and, secondly, to stress that their surgery can be accomplished with acceptable morbidity and rewarding results when those characteristics are considered. A retrospective analysis of 42 cases of benign non-meningeal tumours of the cavernous sinus operated on at Marmara University between April 1992 and April 2003 is presented. The patients were 15 males and 27 females aged 24-72 years. The study cohort consisted of 13 pituitary adenomas, 11 trigeminal schwannomas, seven chordomas, three chondrosarcomas, two juvenile angiofibromas, two epidermoid tumours, one plasmacytoma, one cavernous haemangioma and one internal carotid plexus schwannoma. The 42 patients underwent 46 operations aimed at radical surgical excision. Total resection was achieved in 50% and subtotal resection in 50% of cases. The majority of incompletely resected tumours were pituitary adenomas and chordomas, and 95% required further treatment. Twenty-nine percent of patients developed complications, namely cerebrospinal fluid fistula, haematoma, hydrocephalus, diabetes insipidus, cerebral infarction and cranial nerve palsies. Recurrence was seen in 7.1% of patients. At final follow up at an average of 48.2 months after surgery, the mean Karnofsky performance scale had risen from 83.4 to 87.4. Non-meningeal tumours of the cavernous sinus can be surgically resected with acceptable morbidity and mortality. In selected tumours the results are better than those for cavernous sinus meningiomas. The best surgical results are achieved with interdural tumours of the lateral sinus wall and the worst surgical results are seen in invasive tumours such as chordomas and pituitary adenomas. Individual tumour characteristics are presented in the text.

Adult↗
PubMed2006

Expression of integrins in cerebral arteriovenous and cavernous malformations.

OBJECTIVE: To assess and compare levels and patterns of expression for integrins alphavbeta1, alphavbeta3, and alphavbeta5 in arteriovenous malformations (AVMs) and cavernous malformations (CCMs) of the brain. MATERIALS AND METHODS: Specimens from 10 AVM and 10 CCM lesions were selected from 112 patients with AVMs and 97 patients with CCMs who were treated microsurgically in the Department of Neurosurgery, Marmara University, Istanbul, Turkey. Sections were immunohistochemically stained with antibodies for integrins alphavbeta1, alphavbeta3, and alphavbeta5. Separate histological layers of the vascular wall were evaluated, and levels of expression were graded using a four-tier system. RESULTS: Integrin alphavbeta1 was more strongly expressed in AVMs than in CCMs. This difference was most pronounced in the endothelium and subendothelium/media. Integrin alphavbeta3 was more strongly expressed in CCM endothelium than in AVM endothelium (average grades, 0.9 and 0.4, respectively). All 10 of the CCM lesions expressed integrin alphavbeta5 in the endothelium, whereas only five of the AVMs showed minimal expression of this molecule in the endothelium. CONCLUSION: Current scientific understanding of the roles integrins play in angiogenesis is far from complete. The levels and patterns of expression for these molecules in the histological layers of the vascular walls of AVMs and CCMs provide some clues about the complex biological activities of integrins in these lesions. If one accepts the premise that immunohistochemistry has its inherent methodological problems, integrins alphavbeta1, alphavbeta3, and alphavbeta5 are expressed in AVMs and CCMs in different ways that may be linked to stages of angiogenic maturation. Integrin alphavbeta1 is expressed more strongly in endothelium and subendothelium/media of AVMs than in the corresponding layers of CCMs. Integrins alphavbeta3 and alphavbeta5 are expressed more strongly in CCM endothelium than in AVM endothelium. In addition, integrin alphavbeta5 staining was stronger in CCM subendothelium than AVM subendothelium/media.

Adult↗
PubMed2006

Microanatomy of the central myelin-peripheral myelin transition zone of the trigeminal nerve.

OBJECTIVE: The aim of this study was to evaluate the microanatomy of the central myelin-peripheral myelin transitional zone (TZ) in trigeminal nerves from cadavers. METHODS: One hundred trigeminal nerves from 50 cadaver heads were examined. The cisternal portion of the nerve (from the pons to Meckel's cave) was measured. Horizontal sections were stained and photographed. The photomicrographs were used to measure the extent of central myelin on the medial and lateral aspects of the nerve and to classify TZ shapes. RESULTS: The cisternal portions of the specimens ranged from 8 to 15 mm long (mean, 12.3 mm; median, 11.9 mm). The data from the photomicrographs revealed that the extent of central myelin (distance from pons to TZ) on the medial aspect of the nerve (range, 0.1-2.5 mm; mean, 1.13 mm; median, 1 mm) was shorter than that on the lateral aspect (range, 0.17-6.75 mm; mean, 2.47 mm; median, 2.12 mm). CONCLUSION: The data definitively prove that the root entry zone (REZ, nerve-pons junction) and TZ of the trigeminal nerve are distinct sites and that these terms should never be used interchangeably. The measurements showed that the central myelin occupies only the initial one-fourth of the trigeminal nerve length. If trigeminal neuralgia is caused exclusively by vascular compression of the central myelin, the problem vessel would always have to be located in this region. However, it is well known that pain from trigeminal neuralgia can resolve after vascular decompression at more distal sites. This suggests that the effects of surgical decompression are caused by another mechanism.

Adolescent↗
PubMed2005

Cerebellar hemorrhage after spinal surgery: case report and review of the literature.

Recent reports indicate that cerebellar hemorrhage after spinal surgery is infrequent, but it is an important and preventable problem. This type of bleeding is thought to occur secondary to venous infarction, but the exact pathogenetic mechanisms are unknown. This report details the case of a 48-year-old woman who developed remote cerebellar hemorrhage after spinal surgery. The patient presented with a herniated lumbar disc, spinal stenosis, and spondylolisthesis, and underwent multiple-level laminectomy, discectomy, and transpedicular fixation. The dura mater was opened accidentally during the operation. There were no neurologic deficits in the early postoperative period; however, 12 h postsurgery the patient complained of headache. This became more severe, and developed progressive dysarthria and vomiting as well. Computed tomography demonstrated small sites of remote cerebellar hemorrhage in both cerebellar hemispheres. The patient was treated medically, and was discharged in good condition. At 6 months after surgery, she was neurologically normal. The case is discussed in relation to the ten previous cases of remote cerebellar hemorrhage documented in the literature. The only possible etiological factors identified in the reported case were opening of the dura and large-volume cerebrospinal fluid loss.

Analgesics↗
PubMed2005

The galenic venous system: surgical anatomy and its angiographic and magnetic resonance venographic correlations.

OBJECTIVE: This study aims at evaluating the adequacy of digital subtraction angiography and magnetic resonance venography in imaging of the galenic venous system for surgical planning of approaches to the pineal region. Anatomical dissections were carried out in 10 cadavers of several age groups and these were compared to imaging findings in 10 living subjects. METHODS: The presence or absence of 10 predetermined veins or vein groupings belonging to the galenic venous system were prospectively analyzed in 10 cadaver dissections and imaging findings of 10 age matched human subjects. The studied vessels were the vein of galen, the internal cerebral veins, both basal vein of Rosenthals, internal occipital vein, occipitotemporal veins, precentral cerebellar veins, tectal veins, pineal veins, superior vermian veins (including superior cerebellar veins (SCVs)) and posterior pericallosal veins. Each of the subjects had both digital subtraction angiography and magnetic resonance venography studies performed. Diagnostic digital subtraction angiography was performed using the transfemoral route and the venous phase was used for the study. Magnetic resonance venography was performed in 1.5 T MRI equipment using the 2D-TOF sequence. All studies were reported to be normal. RESULTS: There was wide variation in the anatomy of the galenic venous system. There were interpersonal, intrapersonal and age related variations. Both the digital subtraction angiography and the magnetic resonance venography were efficient at demonstrating large veins. However, smaller veins were less readily demonstrated in either study. The general sensitivities of the digital subtraction angiography and the magnetic resonance venography for the galenic venous system were 45.5% and 32.5%, respectively. Surgically important veins were missed in most studies. CONCLUSIONS: Anatomically, the galenic venous system is highly variable. This variability is caused by interpersonal, intrapersonal and age related differences and causes each individual galenic venous system to be unique. Therefore, modern neurosurgical procedures require anatomical information on individual differences. Current radiological methods of digital subtraction angiography and magnetic resonance venography fail short of providing the necessary information. New and more sophisticated MRI technology may fulfill this need.

Adult↗
PubMed2005

Trigeminal neuralgia in a patient with mitochondrial neurogastrointestinal encephalomyopathy (MNGIE).

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal-recessive disease associated with multiple deletions of mitochondrial DNA in skeletal muscle. MNGIE is a multisystem syndrome affecting muscle, peripheral, and central nervous systems and the gastrointestinal tract. A 25-year-old man is presented with 3 years history of right sided trigeminal neuralgia. He has been diagnosed as MNGIE based on clinical, neurophysiological and pathological findings. He had also received medical therapy and two radiofrequency thermocoagulations for the treatment of trigeminal neuralgia. Gamma Knife radiosurgery was performed and resulted in partial relief. To our knowledge, this is the first case in the literature of MNGIE with trigeminal neuralgia. An analogy is suggested between multiple sclerosis and MNGIE as a cause for trigeminal neuralgia in this patient.

Adult↗
PubMed2005

Suprasellar haemangioblastoma. Report of two cases and review of the literature.

We report 2 patients with suprasellar haemangioblastoma (HBL). The first, a 54-year-old man, presented with headache and gradually worsening bilateral visual field defects that had progressed to complete blindness on the right side. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain demonstrated a suprasellar mass. The mass was removed through a pterional craniotomy. The postoperative course was uneventful. He had no stigmata of von Hippel-Lindau (VHL) disease. After 5 years follow-up, vision in the left eye is normal but the right eye remains blind and MRI reveals no recurrence. The second, a 38-year-old man presented with a 2-month history of severe headaches and complete visual loss in the left eye. He had had surgery for excision of a cerebellar HBL, 5 years prior to this presentation. CT and MRI revealed a residual mass in the posterior fossa and a new suprasellar mass. He underwent craniotomy and subtotal excision of the suprasellar tumour. The histological diagnosis was HBL in both patients. HBL in the sellar and suprasellar region are rare and may be sporadic or occur in association with VHL disease. The literature is reviewed and diagnosis and treatment options discussed.

Adult↗
PubMed2005

Effect of allopurinol in focal cerebral ischemia in rats: an experimental study.

BACKGROUND: Allopurinol is a xanthine oxidase inhibitor that prevents the generation of free radicals and may play a role in the protection of the cells during cerebral ischemia. METHODS: We evaluated the protective and therapeutic effect of allopurinol on reversible focal cerebral ischemia-reperfusion model in rats. Cerebral blood flow to the left hemisphere of adult Sprague-Dawley rats (n = 40) was temporarily interrupted by middle cerebral artery (MCA) and bilateral common carotid artery (CCA) occlusion for 3 hours in 5 groups of 8 rats each. Allopurinol (50 mg/kg) was given intraperitoneally 2 hours and immediately before ischemia and immediately and 2 hours after reperfusion in 4 different groups of rats, respectively. Animals were kept alive 24 hours after reperfusion. After sacrifice, infarction volumes and ratios of the brain slices were calculated, and the results were compared with those of the control group. RESULTS: The difference between the allopurinol-administered group and the control group 2 hours before for both infarction volumes and infarction ratios achieved statistical significance. Regarding the allopurinol-administered group immediately before ischemia, infarction volumes and infarction ratios were diminished, but there was no statistically significant difference. The difference between allopurinol-administered and control group immediately after and 2 hours after reperfusion for both infarction volumes and infarction ratios achieved no statistical significance. CONCLUSION: This study showed that allopurinol has a protective effect, but not a therapeutic effect, on cerebral ischemia.

Allopurinol↗
PubMed2005

Changing treatment strategy of cavernous sinus meningiomas: experience of a single institution.

BACKGROUND: Oncological treatment of a neoplasm is more than surgical removal of the tumor. Probably, this truth is the reason for the ongoing discussion on cavernous sinus meningiomas in the last decade. Debate on optimal management of cavernous sinus meningiomas aims to compare the different treatment strategies: (a) radical surgical resection and (b) conservative surgical resection complemented with radiosurgical treatment. MATERIALS AND METHODS: Natural history of the change in the management strategy of cavernous sinus meningiomas in our department before and after GK facility became available in 1997 allowed us to compare the 2 aforementioned strategies. Before installation of a Leksell GK unit at the hospital in 1997, the neurosurgical team at Marmara University Institute of Neurological Sciences and Faculty of Medicine (Istanbul, Turkey) treated patients with cavernous sinus meningioma using radical resection (radical strategy, group A, 10 patients). After 1997, the same neurosurgical team used understanding of surgical removal of the extracavernous sinus tumor component with GK irradiation of the intracavernous part (conservative strategy, group B, 12 patients). Another group of patients, who were treated with GK as a first-step treatment, was analyzed (GK group, group C, 26 patients). RESULTS: At the end of the third year, more stable tumor volume control was achieved in groups B and C; after the second year, an incline in the tumor volume-time graph was detected. Group B resulted in less cranial nerve-related complications; a certain degree of improvement in cranial nerve deficits was observed. CONCLUSION: Comparing 2 different management strategies for cavernous sinus meningiomas in the same hospital setting using the same neurosurgical group, we conclude that extracavernous resection followed by GK is as effective as radical surgery. Considering cranial nerve complications and third-year tumor volume control achievement, conservative approach yielded better results. Longer follow-up with larger series is necessary.

Adolescent↗
PubMed2005

Testing the angiogenic potential of cerebrovascular malformations by use of a rat cornea model: usefulness and novel assessment of changes over time.

OBJECTIVE: This experimental study assessed the usefulness of a rat model of corneal angiogenesis for assessing the angiogenic activity of cerebrovascular malformations (CVMs) over time. It is the first investigation to have focused on dynamic quantification of angiogenesis related to CVMs (i.e., assessing changes over time as opposed to one point in time) and the first to have compared different CVMs and other tissues in this way. METHODS: The CVM specimens were from 15 randomly selected arteriovenous malformation (AVM) cases, 15 randomly selected cavernous malformation cases, and 2 venous angioma cases. All the samples came from surgical resections performed in the Marmara University Department of Neurosurgery and the Marmara University Institute of Neurological Sciences between January 1998 and January 2003. Glioblastoma multiforme tissues, normal adult brain tissues, and normal brain artery tissues were used as controls. Tissue from each specimen was implanted in one corneal micropocket in each cornea of a single rat, and the level of angiogenic activity in the cornea was graded (low, moderate, or high) at Days 1 through 9 after tissue implantation. Another set of rats was subjected to the same corneal implantation procedure, and two widely accepted indicators of neovascularization, microvessel counts and vascular endothelial growth factor expression, were assessed at Days 3, 5, 7, and 9 after surgery. The tissue-group results for grade of angiogenic activity, microvessel count, and grade of vascular endothelial growth factor expression were compared. RESULTS: Of the three CVM types, the AVMs showed the highest angiogenic activity, cavernous malformations exhibited some degree of angiogenic activity (less than AVMs but more than normal brain artery tissue), and angiogenesis induction by venous angiomas was comparable to that of normal brain artery tissue. Corneas implanted with the AVM samples showed Grade 1 angiogenesis on Day 2, Grade 2 angiogenesis on Day 4, and Grade 2.5 angiogenesis on Day 8. Cavernous malformation samples caused Grade 1 angiogenesis after Day 5, and grading remained less than 1.5. Venous angioma samples resulted in angiogenesis graded less than 1. CONCLUSION: The results showed that this rat model of corneal angiogenesis is of value for assessing the angiogenic potential of CVMs and for evaluating details of the neovascularization process over time. Further investigation of CVMs with this model might yield information about how angiogenesis can be modulated, and this could lead to development of biological treatments that inhibit this process.

Adolescent↗
PubMed2005

Expression of structural proteins and angiogenic factors in normal arterial and unruptured and ruptured aneurysm walls.

OBJECTIVE: To identify differences in the expression of certain structural proteins and angiogenic growth factors in vessel tissues that represent different phases of the process of intracranial aneurysm formation and rupture: normal vessel wall, intact (unruptured) aneurysm wall, and ruptured vessel wall. METHODS: The novel study design involved 10 pairs of specimens (ruptured and unruptured aneurysm wall) obtained perioperatively during clipping operations in 10 patients with multiple aneurysms. All surgeries were performed within 5 days of subarachnoid hemorrhage. As controls, five circle of Willis specimens were obtained from five cadavers. Sections of each of the 25 specimens were separately immunostained for five structural proteins (collagen Types III and IV, alpha-smooth muscle actin, fibronectin, and laminin) and three angiogenic factors (vascular endothelial growth factor, basic fibroblast growth factor, and transforming growth factor-alpha). Levels of expression for each protein and factor were graded, and the average grades for each tissue group were recorded and compared. RESULTS: Among the structural proteins studied, fibronectin specifically is densely expressed in ruptured aneurysms, which is graded as 2.0. However, its expression is less prominent both in nonaneurysmal vessel wall (Grade 1.0) and unruptured aneurysm vessel wall (Grade 1.1). Contrary to fibronectin, laminin is more intensely and regularly expressed in normal vessel wall (Grade 2.7) than in ruptured (Grade 1.1) and unruptured (Grade 1.0) aneurysmal specimens. Among the angiogenic growth factors studied, transforming growth factor-alpha shows a peculiar grading of staining, different from the other two angiogenic factors examined, so that it is more highly expressed in normal circle of Willis specimens (Grade 2.1) than in unruptured and ruptured aneurysm walls, graded as 0.5 and 0.6, respectively. CONCLUSION: Normal vessel wall, unruptured aneurysm wall, and ruptured aneurysm wall exhibit different levels and patterns of expression for the structural proteins and regulator growth factors investigated. If one accepts the premise that immunohistochemical study has its inherent methodological problems, these results suggest that the biological mediators of aneurysm formation in a vessel wall differ from those of the biological mediators of aneurysm rupture. There was a novel finding related to fibronectin and laminin: the results indicated that a rise in the fibronectin-to-laminin ratio in an unruptured aneurysm wall may contribute to rupture. A drop in transforming growth factor-alpha expression in a vessel wall may also contribute to aneurysm formation.

Actins↗
PubMed2004

Cauda equina syndrome after induction of spinal anesthesia.

In this report the authors present a case of cauda equina syndrome that developed following induction of spinal anesthesia in a patient who had no apparent preexisting bleeding abnormality. An acute subdural hematoma caused the syndrome and was believed to have resulted from direct vascular trauma during administration of spinal anesthesia or from vascular trauma combined with thrombocytopenia in the postoperative period.

Aged↗
PubMed2004

Giant intracranial Rosai-Dorfman disease.

Rosai-Dorfman disease is a rare, non-neoplastic disease characterized by an unusual proliferation of histiocytic cells. It rarely manifests intracranially, and only 50 cases of intracranial lesions have been reported. We describe an unusual case of a huge, solid mass in the paranasal sinuses, orbits, cavernous sinuses, and suprasellar cisterns. A 29-year-old patient was admitted to our hospital with nasal obstruction and proptosis and visual loss in the right eye. A biopsy was done at another institution and the diagnosis was "pseudotumor of orbit". A right-sided cranio-orbitozygomatic craniotomy combined with a right-sided lateral rhinotomy was used to excise the tumor with right orbital exenteration. The histopathological diagnosis was consistent with Rosai-Dorfman disease. The patient underwent postoperative chemotherapy. Involvement of the central nervous system in Rosai-Dorfman disease is rare, but the disease's ability to mimic other pathologies underlines its importance.

Adult↗
PubMed2004

Experience of a single institution treating foramen magnum meningiomas.

Despite the introduction of skull base approaches, there is still controversy in the optimum surgical management of foramen magnum meningiomas. Between January 1990 and January 2003, 22 patients underwent 23 surgical procedures with a diagnosis of foramen magnum meningioma at Marmara University, Department of Neurosurgery. The suboccipital approach was used for 2 posteriorly located tumors with radiological total removal. The paramedian suboccipital approach was replaced by the far-lateral modification in the treatment of ventral meningiomas. 1 of the 20 ventral tumors was operated twice. The classical suboccipital approach was followed by the far-lateral modification. A gross-total removal was achieved in 21 patients. The overall morbidity was 32%. No specific and clinically significant complications attributable to the far-lateral modification were observed. The far-lateral approach has improved the success of surgery in ventrally located lesions. The posterior suboccipital approach is still indicated in the removal of lesions placed posterior to the dentate ligament.

Adult↗
PubMed2004

Small petrosal approach to the middle portion of the mediobasal temporal region: technical case report.

BACKGROUND: The mediobasal temporal region has been divided into three portions: anterior, middle, and posterior. Surgical access, especially to the middle portion, presents a formidable challenge to neurosurgeons, and much controversy still exists regarding the selection of the surgical approach to this region. CASE REPORT: We used the small petrosal approach to the middle portion of the mediobasal temporal region in a patient with intractable seizures caused by a cavernous angioma in this region. Using this approach, we selectively removed the lesion without postoperative deficits. CONCLUSIONS: The small petrosal approach was found to be useful and safe as an alternative technique for selective removal of the lesion in the middle portion of the mediobasal temporal region.

Adult↗