PubMed Health⌕ Search

Biomedical subjects

Narendra Nathoo

Publications and source records attributed to Narendra Nathoo.

At least 19 recordsLinked to original sources
PubMed2006

The role of 111indium-octreotide brain scintigraphy in the diagnosis of cranial, dural-based meningiomas.

OBJECTIVE: Meningiomas are common brain tumors with somatostatin receptors that bind octreotide. We report the use of (111)indium-octreotide brain scintigraphy (OBS) for the non-invasive differentiation of meningiomas from other cranial dural-based pathology. METHODS: A retrospective analysis of our experience with OBS for non-invasive identification of meningiomas was performed. Two neuroradiologists, blinded to clinical data, utilized a standardized grading scheme to define the uptake of octreotide at 6 and 24 h post-administration. The correlation between (18) F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), magnetic resonance imaging (MRI) scans, and octreotide uptake was assessed. RESULTS: The cohort consisted of 50 patients having a mean age of 62.4 years and a median follow-up time of 24 months. Management consisted of biopsy (n = 4); resection (n = 10); observation (n = 16); radiosurgery (n = 21); and external beam radiotherapy (n = 3). OBS was correlated with MRI (n = 50); FDG-PET brain studies (n = 38); histology (n = 14), and angiography (n = 1). In cases where definitive diagnosis could be made, the sensitivity, specificity, positive and negative predictor values for OBS alone were 100; 50; 75; and 100, respectively. OBS provided false positive data in 3 patients (metastasis, chronic inflammation, lymphoma). Use of OBS with MRI to differentiate meningiomas from other lesions was highly significant (P < 0.001). FDG-PET correctly identified malignant pathology with 100% sensitivity and specificity. CONCLUSION: OBS may increase the diagnostic specificity of conventional MRI when differentiating meningioma from other dural-based pathologies, while the addition of FDG-PET differentiates benign from malignant lesions.

Adult↗
PubMed2006

Increased expression of 5-lipoxygenase in high-grade astrocytomas.

OBJECTIVE: 5-Lipoxygenase (5-LO) oxidizes arachidonic acid into proinflammatory eicosanoids that may promote tumorigenesis. In this study, we investigated whether 5-LO is expressed in human astrocytomas and what effect its expression may have on patient outcome. METHODS: Increased 5-LO messenger ribonucleic acid and protein expression was detected by the polymerase chain reaction and antibody-based approaches, respectively, in surgical astrocytoma specimens and established glioblastoma multiforme cell lines compared with primary cell culture from the human white matter. RESULTS: Immunohistochemical analysis revealed predominantly nuclear 5-LO staining in 44 of 49 glioblastoma multiforme samples (90%), 8 of 10 (80%) anaplastic astrocytomas samples, and 3 of 13 (23%) low-grade astrocytoma samples analyzed. Double-staining experiments with anti-CD-68 (macrophage/microglial marker) and anti-5-LO antibodies suggest that both CD-68-positive and CD-68-negative tumor cells express 5-LO protein. Staining of 5-LO was significantly more frequent in high-grade than in low-grade tumors (P = 0.001). Patients whose tumors expressed 5-LO were significantly older, had lower preoperative Karnofsky performance scores and shorter survival than patients whose tumors did not express 5-LO. After adjusting for pathological diagnosis and age, respectively, neither Karnofsky performance score nor survival were significantly associated with 5-LO staining. CONCLUSION: These data indicate that 5-LO is overexpressed in high-grade astrocytomas and supports the idea that eicosanoids may play a role in tumorigenesis of these brain tumors.

Adult↗
PubMed2006

Gamma knife radiosurgery for glomus jugulare tumors: volumetric analysis in 17 patients.

OBJECTIVE: Stereotactic radiosurgery has been used increasingly for the treatment of glomus jugulare tumors. The authors report their experience treating these tumors using gamma knife radiosurgery (GKRS), documenting the clinical and radiological outcome. METHODS: A retrospective analysis identified 17 patients with glomus jugulare tumors who underwent GKRS. Besides analysis of clinical outcome, a radiological volumetric analysis was also performed after treatment. RESULTS: There were 15 women and two men (average age, 63.1 yr) with a median follow-up period of 48 months. The median radiosurgical dose to the tumor margin was 15 Gy (range, 13-18 Gy). Eight patients (47.1%) improved clinically, two (11.8%) worsened, and seven (41.2%) were unchanged. No relationship between internal auditory canal dose and hearing loss was recorded. Tinnitus and otalgia were the symptoms that responded most favorably to GKRS. No patients experienced new lower cranial nerve palsies after GKRS. Tumor volume showed a transient increase in seven patients. Analysis of tumor volume at the time of the last magnetic resonance imaging scan recorded a decrease in eight patients, an increase in four patients, and no change in five patients. CONCLUSION: GKRS is a safe, effective treatment for glomus jugulare tumors, particularly in patients with preserved glossopharyngeal and vagus nerve function, after surgical recurrence, in the elderly, and in patients with serious preexisting medical conditions. Longer follow-up periods are required to assess long-term effects.

Adult↗
PubMed2005

Blind transpyloric nasojejunal versus nasogastric tube intubation in severe head injuries: a preliminary report.

AIM: To compare the efficacy of blind transpyloric placement using a specifically designed nasojejunal tube (NJT) versus a standard nasogastric tube (NGT) in severe head injury (SHI). METHODS: This was a randomised trial conducted in a neurosurgical intensive care unit. Fourteen patients were enrolled with a Glasgow Coma Score (GCS) less than 8 (mean 6.8 SEM+/-0.36). Patients were randomised to receive either NJT or NGT. RESULTS: There was an 83% (5/6 patients) spontaneous jejunal placement rate of NJT past the ligament of Treitz. The 17% (1/6 patients) jejunal placement failure rate for NJT was due to inappropriate technique. A 100% (8/8 patients) failure of the unweighted NGTs to pass through the pylorus into the jejunum was recorded (P=0.002). CONCLUSION: In SHI, the specifically designed self-propelling NJT was effective in spontaneous transpyloric placement past the ligament of Treitz within 12h of introduction into the gastric cavity. The standard un-weighted NGT was ineffective. Additional studies are warranted to determine the clinical efficacy of this self-propelling NJT.

Adolescent↗
PubMed2005

In touch with robotics: neurosurgery for the future.

The introduction of multiple front-end technologies during the past quarter century has generated an emerging futurism for the discipline of neurological surgery. Driven primarily by synergistic developments in science and engineering, neurosurgery has always managed to harness the potential of the latest technical developments. Robotics represents one such technology. Progress in development of this technology has resulted in new uses for robotic devices in our discipline, which are accompanied by new potential dangers and inherent risks. The recent surge in robot-assisted interventions in other disciplines suggests that this technology may be considered one of a spectrum of frontier technologies poised to fuel the development of neurosurgery and consolidate the era of minimalism. On a more practical level, if the introduction of robotics in neurosurgery proves beneficial, neurosurgeons will need to become facile with this technology and learn to harness its potential so that the best surgical results may be achieved in the least invasive manner. This article reviews the role of robotic technology in the context of neurosurgery.

Equipment Design↗
PubMed2005

Trigeminal nerve schwannoma with ancient change. Case report and review of the literature.

Ancient change in a schwannoma is a histological variant typically found in longstanding tumors. Histologically, the tumor has biphasic features typical of a schwannoma with evidence of degenerative changes that may complicate diagnosis. The authors report on a 23-year-old man with no features of neurofibromatosis who presented with headaches, blurred vision, and ataxic gait. Magnetic resonance imaging demonstrated a rim-enhancing lesion in the cerebellopontine angle with displacement of brainstem structures and no supratentorial hydrocephalus. Using a lateral suboccipital approach together with image guidance and intraoperative neurophysiological monitoring, a gross-total macroscopic excision was performed. At surgery, the tumor was found to arise from the inferior division of the trigeminal nerve. The final histological diagnosis was schwannoma with ancient change. Note that ancient change in schwannomas is a histological variant thought to result from degenerative changes in longstanding tumors. To the authors' knowledge, this is the first independent report of this histological variant in an intracranial schwannoma.

Adult↗
PubMed2005

George W. Crile, Ohio's first neurosurgeon, and his relationship with Harvey Cushing.

Much has been written about Harvey Cushing, his contributions to neurosurgery, and his relationship with many of his contemporaries. Nevertheless, there is no independent report documenting his relationship with Ohio's first neurosurgeon, George W. Crile. Crile's role as a neurosurgeon is limited to the late nineteenth and early twentieth centuries, and he is best remembered for other accomplishments. Father of physiological surgery, pioneering surgeon, innovator, inventor, soldier, and the principal founder of the Cleveland Clinic Foundation, Crile lived during the golden era of surgery, when the discipline was evolving from a crude and chancy art to an applied science. Crile achieved distinction by performing and describing the first successful radical neck dissection for head and neck cancers and the first successful direct human-to-human blood transfusion. He helped introduce the measurement of blood pressure during surgery, first used cocaine for regional anesthesia in the US, proposed "anoci-anesthesia" to prevent shock during surgery, helped establish one of the first nurse anesthetist schools, and invented the Crile forceps and the pneumatic suit, which was the forerunner to the aviator's antigravity suit. He was a founding member of the American College of Surgeons, its second president (1916-1917), and chairman of the Board of Regents (1913-1939). Crile was a teacher, lecturer, and author who published more than 400 papers and 24 books. In this report the authors trace the relationship between Crile and Cushing from their initial competition for a staff surgeon's position to their common interest in blood pressure, and their roles in the American Ambulance in France and later in World War I.

Anesthesia, General↗
PubMed2004

Collagen matrix (DuraGen) in dural repair: analysis of a new modified technique.

STUDY DESIGN: Retrospective review of 110 patients undergoing spinal dural repair and regeneration using an onlay, suture-free, 3-dimensional-collagen matrix graft (DuraGen) over an 8-year period (1995-2003). OBJECTIVES: Technique appraisal of collagen matrix to repair spinal dura following incidental durotomy, spinal tumor surgery, and trauma. SUMMARY OF BACKGROUND DATA: Traditional methods of spinal dural repair following incidental durotomy involve tedious attempts at primary watertight suture with a 5% to 10% failure rate. Dural injury occurs after trauma, or dural excision may be required after tumor resection. Collagen matrix is a newer development in collagen sponge. METHODS: The clinical and demographic data included diagnosis, type and site of surgery, infection risk, size of defect, use of lumbar drains, closed suction subfascial drains, and adverse events. The primary endpoints of graft failure were cerebrospinal fluid leak and pseudomeningocele formation. Neurosurgical wound infection rates were determined. RESULTS: Collagen matrix was used (n = 110) in the following conditions: degenerative (69), pseudomeningocele formation repair (4), tumors (14), trauma (13), and congenital (5). There were 15 cervical (10 anterior), 21 thoracic (3 anterior), and 71 lumbar (all posterior) surgeries. Fibrin glue was used in 7.3%, subfascial drains in 82%, and lumbar drainage in 2.7%. Overall, cerebrospinal fluid leaks occurred in 2.7%. The 2 pseudomeningocele formations (3.2%) resolved at 3 months. There were 2 wound infections. In the subgroup with incidental durotomy (n = 69), failure of cerebrospinal fluid containment occurred in 4.3% [1 cerebrospinal fluid leak (1.4%), 2 pseudomeningocele formations (2.9%)]. CONCLUSIONS: Collagen matrix was successful in cerebrospinal fluid containment in > 95% of patients requiring dural repair following anterior and posterior spinal surgery. Subfascial drains were safe. Routine lumbar drains are not required but are recommended for repair of established pseudomeningocele formations.

Adolescent↗
PubMed2004

Evaluation of the behaviour of a thermal diffusion sensor in a high field strength magnetic resonance system: an experimental study.

Patients with acute brain pathology requiring ferromagnetic bio-medical implants for on-going invasive monitoring are largely excluded from the benefits of MRI scanning. We evaluated the behaviour of a thermal diffusion cortical blood flow (TD-CBF) sensor both in vitro (phantom gelatin model) and in vivo environments in a high field strength MRI system. Two baboons underwent cranial subdural implantation of 2 TD-CBF sensors/hemisphere and a single left parietal sensor was implanted subcortically to determine any deleterious effects. Using standard MRI sequences, artefact size, thermal effects, current generation, movement and reliability of recordings were assessed during scanning. The deflection forces were negligible, no observable thermal effects were demonstrated, while wide fluctuations in cerebral blood flow recordings were recorded. Mean image artefact size for implanted sensors was 6 times larger than in vitro. Patients with an implanted TD-CBF sensor may be safely imaged provided the device is disconnected. The MRI images obtained are of an acceptable quality.

Animals↗
PubMed2004

Epidermal growth factor receptor antagonists: novel therapy for the treatment of high-grade gliomas.

Overactivation of epidermal growth factor receptor (EGFR) signaling has been recognized as an important step in the pathogenesis and progression of multiple forms of cancer of epithelial origin. This knowledge has led to a surge of interest in novel anticancer therapies targeting key constituents of the EGFR signal transduction pathway. Several molecular strategies have been developed recently to modulate either EGFR or the downstream signal beyond the cell surface receptor. The important role of aberrant EGFR signaling in the progression of malignant gliomas makes EGFR-targeted therapies of particular interest in this form of cancer. The use of anti-EGFR therapies against malignant brain tumors, although in its infancy, promises to yield exciting results as these new drugs probably will enhance the usefulness of existing therapies.

Brain Neoplasms↗
PubMed2004

Metastases to the brain: current management perspectives.

Brain metastases are ten-times more common than primary brain tumors and are a common complication in patients with systemic cancer. The most common sources of brain metastases are lung and breast cancers, although in 15% of patients, the primary site is unknown. Optimal treatment is dependant upon tumor location, size, number of tumors and status of the systemic disease. Currently, management of brain metastases with surgery, radiotherapy and stereotactic radiosurgery is known to improve the quality of life and even life expectancy for selected patients. Techniques under investigation include focal radiation techniques, magnetic resonance imaging guided thermal ablation of metastases, drug delivery modes that bypass the blood-brain barrier and novel drug and molecular therapeutics. Efforts are ongoing to understand the molecular biology of brain metastases.

Anticonvulsants↗
PubMed2004

W. James Gardner: pioneer neurosurgeon and inventor.

W. James Gardner, a skillful neurosurgeon and inventor, is best remembered for his cervical tongs and hydrodynamic theory of syringomyelia. A pioneer of modern neurosurgery, Gardner trained under Charles Frazier in Philadelphia, and in 1929 he moved to Ohio where he became chief of neurosurgery at the Cleveland Clinic, a position he was to hold for the next 33 years. A large surgical practice made it imperative for Gardner to develop surgical methods that were quick, effective, and advantageous for patient and surgeon. He was an early proponent of the sitting position for patients undergoing cranial surgery, which led to the development of a neurosurgical chair with a head fixation device. To reduce the risks of hypotension and air embolism when the patient is in the sitting position, Gardner invented the clinical G suit. He was the first to advocate and use induced arterial hypotension for intracranial surgery and the first neurosurgeon in the US to publish his experiences performing lumbar discography. He converted an operating table so that he could induce hypothermia during aneurysm surgery and then applied pneumatic cuffs to occlude the major arterial supply to the brain. His pioneering work has been documented in many other areas such as hemifacial spasm and trigeminal neuralgia, for which he performed the first vascular decompression, in cervical sympathectomy for treatment of various ailments, and in the use of intrathecally delivered steroid drugs for sciatica. During his career, he authored 256 publications and one book on the dysraphic states. Many of his contributions to the discipline of neurosurgery are now taken for granted.

Craniotomy↗
PubMed2004

Influence of apoptosis on neurological outcome following traumatic cerebral contusion.

OBJECT: Apoptosis has increasingly been implicated in the pathobiology of traumatic brain injury (TBI). The present study was undertaken to confirm the presence of apoptosis in the periischemic zone (PIZ) of traumatic cerebral contusions and to determine the role of apoptosis, if any, in neurological outcome. METHODS: Brain tissue harvested at Wentworth Hospital from the PIZ in 29 patients with traumatic supratentorial contusions was compared with brain tissue resected in patients with epilepsy. Immunohistochemical analyses were performed on the tissues to see if they contained the apoptosis-related proteins p53, bcl-2, bax, and caspase-3. The findings were then correlated to demographic, clinical, surgical, neuroimaging, and outcome data. In the PIZ significant increases of bax (18-fold; p < 0.005) and caspase-3 (20-fold; p < 0.005) were recorded, whereas bcl-2 was upregulated in only 14 patients (48.3%; 2.9-fold increase) compared with control tissue. Patients in the bcl-2-positive group exhibited improved outcomes at the 18-month follow-up examination despite an older mean age and lower mean admission Glasgow Coma Scale score (p < 0.03). Caspase-3 immunostaining was increased in those patients who died (Glasgow Outcome Scale [GOS] Score 1, 12 patients) when compared with those who experienced a good outcome (GOS Score 4 or 5, 17 patients) (p < 0.005). Regression analysis identified bcl-2-negative status (p < 0.04, odds ratio [OR] 5.5; 95% confidence interval [CI] 1.1-28.4) and caspase-3-positive status (p < 0.01, OR 1.4, 95% CI 1.1-1.8) as independent predictors of poor outcome. No immunostaining for p53 was recorded in the TBI specimens. CONCLUSIONS: The present findings confirm apoptosis in the PIZ of traumatic cerebral contusions and indicate that this form of cell death can influence neurological outcome following a TBI.

Adolescent↗
PubMed2003

Robotics and neurosurgery.

Ultimately, neurosurgery performed via a robotic interface will serve to improve the standard of a neurosurgeon's skills, thus making a good surgeon a better surgeon. In fact, computer and robotic instrumentation will become allies to the neurosurgeon through the use of these technologies in training, diagnostic, and surgical events. Nonetheless, these technologies are still in an early stage of development, and each device developed will entail its own set of challenges and limitations for use in clinical settings. The future operating room should be regarded as an integrated information system incorporating robotic surgical navigators and telecontrolled micromanipulators, with the capabilities of all principal neurosurgical concepts, sharing information, and under the control of a single person, the neurosurgeon. The eventual integration of robotic technology into mainstream clinical neurosurgery offers the promise of a future of safer, more accurate, and less invasive surgery that will result in improved patient outcome.

Clinical Competence↗
PubMed2003

Long-term results after radiosurgery for benign intracranial tumors.

BACKGROUND: Stereotactic radiosurgery is the principal therapeutic alternative to resecting benign intracranial tumors. The goals of radiosurgery are the long-term prevention of tumor growth, the maintenance of patient function, and the prevention of new neurological deficits or adverse radiation effects. Evaluation of long-term outcomes more than 10 years after radiosurgery is needed. METHODS: We evaluated 285 consecutive patients who underwent radiosurgery for benign intracranial tumors between 1987 and 1992. Serial imaging studies were obtained, and clinical evaluations were performed. Our series included 157 patients with vestibular schwannomas, 85 patients with meningiomas, 28 patients with pituitary adenomas, 10 patients with other cranial nerve schwannomas, and 5 patients with craniopharyngiomas. Prior surgical resection had been performed in 44% of these patients, and prior radiotherapy had been administered in 5%. The median follow-up period was 10 years. RESULTS: Overall, 95% of the 285 patients in this series had imaging-defined local tumor control (63% had tumor regression, and 32% had no further tumor growth). The actuarial tumor control rate at 15 years was 93.7%. In 5% of the patients, delayed tumor growth was identified. Resection was performed after radiosurgery in 13 patients (5%). No patient developed a radiation-induced tumor. Eighty-one percent of the patients were still alive at the time of this analysis. Normal facial nerve function was maintained in 95% of patients who had normal function before undergoing treatment for acoustic neuromas. CONCLUSION: Stereotactic radiosurgery provided high rates of tumor growth control, often with tumor regression, and low morbidity rates in patients with benign intracranial tumors when evaluated over the long term. This study supports radiosurgery as a reliable alternative to surgical resection for selected patients with benign intracranial tumors.

Adolescent↗