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Biomedical subjects

G C Fabinyi

Publications and source records attributed to G C Fabinyi.

At least 19 recordsLinked to original sources
PubMed2000

Intraoperative monitoring to preserve central visual fields during occipital corticectomy for epilepsy.

Photic driving using a flashing strobe light was recorded via intracranial electrodes in two patients with occipital epilepsy being evaluated for surgery. The same technique was used to monitor the visual cortex intraoperatively. Visual evoked potentials (VEPs) were also obtained using the intracranial electrodes in one patient. Preoperative photic driving occurred in a separate location from the cortical areas producing ictal epileptiform activity. VEPs were located in the same site as photic driving. Photic driving was monitored throughout the resection and remained unaffected at the end of each procedure. Postoperative visual field testing in both patients showed preservation of central vision although some reduction in peripheral fields was seen. Intraoperative monitoring of the visual cortex using photic stimulation proved to be a reliable technique for preserving central vision during occipital lobe surgery.

Adult↗
PubMed2000

Spontaneous haemorrhage into an empty sella turcica mimicking pituitary apoplexy.

We present a case of spontaneous haemorrhage into an empty sella turcica with the features of subclinical pituitary apoplexy. A 66-year-old woman with a previously resected pituitary adenoma presented four months later with progressive headache and visual deterioration. Cranial MRI demonstrated hyperacute blood products in a recurrent pituitary adenoma. Operative findings were of subacute blood in an empty sella turcica. There was no operative or subsequent histological evidence of tumour recurrence. The intrasellar haemorrhage was evacuated via a trans-sphenoidal approach, resulting in a rapid improvement in visual function. Endocrine deficits required thyroxine, corticosteroid and desmopressin supplementation. Haemorrhage into an empty sella turcica has not been previously described and needs to be suspected as a clinical entity in patients presenting with the features of pituitary apoplexy. Awareness of this clinical condition will prevent preoperative misdiagnosis.

Aged↗
PubMed1999

Motor cortex localization using functional MRI and transcranial magnetic stimulation.

OBJECTIVE: Congenital brain lesions producing focal seizures may be accompanied by reorganization of the areas responsible for motor and sensory functions within the brain due to a phenomenon that has been termed "neuronal plasticity." This can be studied using functional MRI (fMRI) and transcranial magnetic stimulation (TMS). Using either method, the motor cortex can be localized noninvasively, but to date there have been few studies correlating the level of agreement between the two techniques. METHODS: We used fMRI and TMS to localize the motor cortex in a young woman with intractable focal seizures, congenital left arm weakness, and a dysplastic right hemisphere on MRI. RESULTS: There was excellent agreement in the localization of motor representation for each hand. Both were predominantly located in the left hemisphere. fMRI also showed an area of posterior activation in the right hemisphere, but there was no evidence of descending corticospinal projections from this site using TMS, direct cortical stimulation, and Wada testing. CONCLUSIONS: Functional MRI (fMRI) and transcranial magnetic stimulation (TMS) were successfully used to localize cortical motor function before epilepsy surgery. Each technique demonstrated migration of motor function for the left hand to the left motor cortex. After resection of the dysplastic right precentral gyrus there was no permanent increase in weakness or disability. The two techniques are complementary; fMRI indicates all cortical areas activated by the motor task, whereas TMS identifies only those areas giving rise to corticospinal projections.

Adult↗
PubMed1999

Presurgical evaluation of the motor hand area with functional MR imaging in patients with tumors and dysplastic lesions.

PURPOSE: To test an optimized functional magnetic resonance (MR) imaging procedure to depict the motor hand representation area (HRA) in patients with epilepsy lesions near the central sulcus. MATERIALS AND METHODS: Fast low-angle shot MR imaging was performed with an oblique single-section imaging technique in eight control subjects (10 hemispheres) and six patients (12 hemispheres). Three series of five activation images (obtained while subjects performed repetitive finger-to-thumb opposition movements) and five rest images were acquired. Each hemisphere was studied in three adjacent sections. Difference maps (obtained with simple subtraction between activation and rest images) were compared with t-test maps. RESULTS: In control subjects, the HRA was visible in 27 of 30 sections. Qualitatively, activation was seen better on t-test maps in 14 and on difference maps in four of these sections. In all patients, motor activation could be seen in the hemisphere that contained the lesion. This activation was considered normal in four patients. In two patients, the HRA was deformed. Functional MR imaging activation in the motor area was confirmed with Penfield stimulation in five patients. CONCLUSION: Functional MR imaging findings in the preoperative assessment of dysplastic lesions around the central sulcus are the same as for tumors. t-test maps are superior to difference maps in the treatment of motor functional MR imaging data.

Adult↗
PubMed1997

Perfusion patterns during temporal lobe seizures: relationship to surgical outcome.

We sought to determine whether patterns of ictal hyperfusion demonstrated using [99mTC]HMPAO (hexamethylpropylene amine oxime) single photon emission computed tomography (SPECT) predict outcome of temporal lobectomy; in particular, whether the more extensive patterns of ictal hyperperfusion are associated with poor outcome. We studied 63 patients who had ictal SPECT studies prior to temporal lobectomy. Hyperperfusion on ictal SPECT scans was lateralized, and classified into: (i) 'typical', (ii) 'typical with posterior extension', (iii) 'bilateral' and (iv) 'atypical' patterns. Outcome (minimum of 2 years follow-up) was classified as either seizure free, or not seizure free. Actuarial analysis was used to test the relationship of SPECT patterns with outcome. There were 35 cases with the typical ictal SPECT pattern, 13 posterior, nine bilateral and six atypical cases. The atypical pattern was associated with lack of pathology in the surgical specimen. Outcome was similar for the typical, posterior and bilateral with 60%, 69% and 67% seizure free, respectively. In contrast, the atypical group had a worse outcome with only 33% seizure free. Actuarial analysis showed a significant difference in outcome between patients with the typical pattern, and patients with the atypical pattern (P = 0.04). We conclude that extended patterns of ictal perfusion in temporal lobe epilepsy do not predict poor outcome, indicating that extended hyperperfusion probably represents seizure propagation pathways rather than intrinsically epileptogenic tissue. Atypical patterns of hyperperfusion are associated with poor outcome and may indicate diffuse or extra-temporal epileptogenicity.

Actuarial Analysis↗
PubMed1995

Preoperative MRI predicts outcome of temporal lobectomy: an actuarial analysis.

We used actuarial methods to study outcome after temporal lobectomy in 135 consecutive patients classified into subgroups according to preoperative MRI findings. Sixty months after surgery, 69% of patients with foreign tissue lesions, 50% with hippocampal sclerosis, and 21% with normal MRIs had no postoperative seizures. An eventual seizure-free state of 2 years or more, whether the patient was seizure-free since surgery or not, was achieved by 80% of patients with foreign tissue lesions, 62% of those with hippocampal sclerosis, and 36% of those with normal MRIs. Outcome was worse in those with normal MRIs than in the other two groups. Early postoperative seizures with later remission (the "running down" phenomenon) occurred in all groups. Late seizure recurrence was present only in the hippocampal sclerosis group. These data show that preoperative MRI is a useful predictor of outcome and that actuarial analysis provides insight into different longitudinal patterns of outcome in MRI subgroups. This information can now be used in preoperative counseling.

Actuarial Analysis↗
PubMed1993

Surgical damage stimulates proliferation of dopamine uptake sites in normal mouse brain.

To test the hypothesis that proliferation of host dopaminergic tissue in response to injury plays an important role in the response to intrastriatal grafting, we transplanted autologous adrenal medullary to striatum in normal C57-black mice and compared this procedure with transplantation of non-dopaminergic tissue (frontal cortex) or a non-cellular matrix (Gelfoam). [3H]Mazindol autoradiography revealed that all three protocols resulted in a marked proliferation of dopamine uptake sites 10 months after transplantation.

Adrenal Medulla↗
PubMed1993

Craniotomy and thoracotomy for non-small cell carcinoma of the lung with cerebral metastasis.

Twenty patients with non-small cell carcinoma of the lung who had cerebral metastasis, were treated by craniotomy and thoracotomy. Eighteen of these patients had a solitary metastasis and all were treated as curable. Ten patients presented with synchronous lung and brain disease. Of the remaining 10, nine initially presented with the lung tumour, which was treated first. There was a zero operative mortality rate and median survival was 12 months with reasonable quality of life for this time.

Adult↗
PubMed1993

Localised neuronal migration disorder and intractable epilepsy: a prenatal vascular aetiology.

Localised neuronal heterotopias are an increasingly recognised cause of intractable focal epilepsies. The aetiology of these circumscribed disorders of neuronal migration is often unknown although in some instances proximity to areas of prenatal infarction suggests that severe ischaemia was responsible. A patient is described with intractable complex partial seizures associated with heterotopic grey matter and cerebral hypoplasia confined to the territory of the left posterior cerebral artery; the left hippocampus was spared. Angiography showed a normal left anterior choroidal artery but a hypoplastic left posterior cerebral artery, implicating prenatal ischaemia without frank infarction as the aetiology of the malformation.

Adult↗
PubMed1991

Evidence for plasticity of the dopaminergic system in parkinsonism.

A series of compensatory mechanisms within the dopaminergic system have been shown to maintain clinical function in the presence of dopamine loss. Experimental evidence for increased presynaptic dopamine turnover owing to increased dopamine synthesis, release, and reduced reuptake exists. Direct evidence that these mechanisms maintain extracellular dopamine levels is provided by intracerebral microdialysis techniques. Postsynaptic denervation supersensitivity clearly occurs with D2 dopamine receptors, although this is less evident with D1 receptors. Similarly, mechanisms of plasticity have been shown to be relevant in human postmortem and Positron Emission Tomographic studies of patients with Parkinson's disease. However, although presynaptic increases in dopamine turnover are well documented, postsynaptic D1 and D2 receptor changes have been more difficult to establish, mainly because of methodological difficulties. D2, but not D1, receptor increases have been documented in drug naive Parkinsonian patients with PET techniques. In transplantation of adrenal gland to striatum in animal models and patients with Parkinsonism where clinical improvement occurs, plasticity of host response may be as important as plasticity of the graft. Although some elements of the compensatory mechanism of dopamine plasticity may be deleterious, such as dyskinesias owing to dopamine receptor supersensitivity, the overall effect of delay and minimization of the clinical expression of disease is advantageous. An even greater understanding of the mechanisms involved may assist in developing future therapeutic strategies.

Adrenal Glands↗
PubMed1990

Subarachnoid haemorrhage due to cauda equina haemangiopericytoma.

A case of cauda equina haemangiopericytoma presenting with spinal subarachnoid haemorrhage is reported. The tumour had been asymptomatic until 2 weeks prior to presentation, and resulted in complete paraplegia below L3. The authors underline the uncommon association of spinal subarachnoid haemorrhage and cauda equina tumour and the rare finding of a cauda equina haemangiopericytoma.

Aged↗
PubMed1990

Hippocampal sclerosis can be reliably detected by magnetic resonance imaging.

Two independent blinded observers reported the preoperative MRIs in a series of 81 consecutive patients with intractable temporal lobe epilepsy who were undergoing temporal lobectomy. We then compared the nature and lateralization of the MRI abnormalities with the pathologic diagnosis and the side of lobectomy. The MRI criteria of hippocampal sclerosis were an increased T2-weighted signal and the signal's confinement to a unilaterally small hippocampus. Imaging was performed in coronal and axial planes, specially orientated along and perpendicular to the long axis of the hippocampal body. We found diagnostic MRI abnormalities in 25 of the 27 cases with pathologically proven hippocampal sclerosis (sensitivity 93%, specificity 86%). In addition, we detected all 13 foreign tissue lesions on MRI. Overall, we detected lateralized lesions on MRI that correctly predicted the side of the epileptogenic temporal lobe in 72 cases (89%), with 2 possible errors. A learning effect in appreciating the relatively subtle MRI changes of hippocampal sclerosis was apparent in our later cases, as shown by an improved correlation between the 2 observers. This study demonstrates that hippocampal sclerosis can be identified on MRI with a high degree of sensitivity and specificity.

Brain Neoplasms↗
PubMed1988

Blunt trauma to the carotid artery.

Non-penetrating trauma to the internal carotid artery presenting as an immediate or delayed neurological deficit is an uncommon clinical entity. It has a high reported morbidity and mortality. Three cases are presented with long-term clinical and radiological follow-up. The mechanisms of injury, clinical features and possible treatment modalities are discussed.

Accidents, Traffic↗
PubMed1985

Ophthalmic manifestations of pituitary apoplexy.

A case of pituitary apoplexy which occurred in a patient with prolactinoma is reported. The signs and symptoms on presentation were headache, loss of vision, sixth-nerve palsy, subarachnoid haemorrhage and fever. Physicians are alerted to the necessity of prompt and accurate diagnosis in this condition to allow urgent decompression of the anterior visual pathways.

Adenoma↗
PubMed1981

Bupivacaine infiltration after lumbar laminectomy. Local infiltration in the control of early postoperative lumbar laminectomy pain.

This is a report of a double-bind controlled trial to test the hypothesis that peroperative local infiltration of the wound of lumbar laminectomy with bupivacaine produces a significant reduction in postoperative back pain. No such effect was demonstrated when the linear analogue was used to record the patients' subjective response to pain. It is suggested that this treatment is not indicated as a routine method.

Adult↗