Biomedical subjects

G Nesbit

Publications and source records attributed to G Nesbit.

7 recordsLinked to original sources

PubMed2005

Asynchronous regional brain volume losses in presymptomatic to moderate AD.

To determine if rates and locations of brain volume loss associated with AD are phase-specific, occurring prior to clinical onset and at later stages, we performed longitudinal volumetric MRI analysis on 155 subjects enrolled in a prospective study of aging and dementia. Subjects were divided by Clinical Dementia Rating (CDR) scale into stages of Normal (CDR 0 --> 0), Very Mild (CDR 0 --> 0.5 and 0.5 --> 0.5), Mild (CDR 0.5 --> 1.0 and 1.0 --> 1.0) and Moderate (CDR 1.0 --> 2.0 and 2.0 --> 2.0) dementia. Rates of volume change in CSF spaces, lobar and medial temporal lobe regions were analyzed for group differences across stages. Annual rates of ventricular volume change differed between non-demented and very mild group (p<0.01). In later severity stages, ventricular, temporal, basal ganglia-thalamic region and total volumes show change. Rates of volume loss increase as dementia progresses, but not uniformly in all regions. These regional and phase-specific volume changes form targets for monitoring disease-modifying therapies at clinically relevant, defined stages of dementia.

Aged↗

PubMed2004

Imaging of iron oxide nanoparticles by MR and light microscopy in patients with malignant brain tumours.

OBJECTIVE: Ferumoxtran-10 (Combidex), a dextran-coated iron oxide nanoparticle, provides enhancement of intracranial tumours by magnetic resonance (MR) for more than 24 h and can be imaged histologically by iron staining. Our goal was to compare ferumoxtran imaging and histochemistry vs. gadolinium enhancement in malignant brain tumours on preoperative and postoperative MR. METHODS: Seven patients with primary and metastatic malignant tumours underwent MR imaging with gadolinium and ferumoxtran both pre- and postoperatively. Normalized signal intensities on the ferumoxtran-enhanced scans were determined in representative regions of interest. Resected tissue from six ferumoxtran patients and from three patients who did not receive ferumoxtran was assessed for localization of iron in tumour and reactive brain. RESULTS: All malignant tumours (all of which enhanced by gadolinium MR) showed ferumoxtran accumulation with T1 and T2 signal changes, even using a 0.15 T intraoperative MR unit in one patient. Iron staining was predominantly in reactive cells (reactive astrocytes and macrophages) and not tumour cells. In five of the seven patients, including two patients who showed additional lesions, areas enhancing with ferumoxtran but not with gadolinium were observed. Comparison of the pre- and postoperative MR revealed residual ferumoxtran-enhancing areas in four of seven cases. CONCLUSION: In malignant tumours, ferumoxtran may show areas of enhancement, even with a 0.15 T intraoperative MR, that do not enhance with gadolinium. Ferumoxtran-enhancing lesions have persistent increased T1 signal intensity for 2-5 days, which may provide advantages over gadolinium for postoperative imaging. Histochemistry for iron shows uptake of ferumoxtran in reactive cells (astrocytes and macrophages) rather than tumour cells.

Adult↗

PubMed2003

Remarkable improvement in adult Leigh syndrome with partial cytochrome c oxidase deficiency.

Leigh syndrome (LS) is a heterogeneous disorder, usually due to a defect in oxidative metabolism. Typically, signs and symptoms commence in infancy or childhood, although rare cases of adult onset have been described. Progressive deterioration is the norm. The authors describe a 22-year-old woman with partial cytochrome c oxidase deficiency who developed fulminant LS following an acute febrile illness and who subsequently showed dramatic clinical and neuroradiologic improvement.

Adult↗

PubMed2000

Spontaneous brachial plexus hemorrhage-case report.

BACKGROUND: Shoulder hemorrhage resulting in brachial plexus neuropathy is a rare occurrence most often seen in cases of traumatic injury or anticoagulation therapy. We report a unique case of spontaneous brachial plexus hemorrhage. CASE DESCRIPTION: This is the first report of a spontaneous shoulder hemorrhage in which a 48-year-old jackhammer operator presented to the emergency department with a sudden onset of right shoulder pain and upper extremity pain and numbness. Imaging studies revealed a hematoma in the right axilla and chest wall. Without evidence of active bleeding or worsening neurologic deficit, this patient was treated conservatively with pain control and observation and eventually experienced a full recovery. Had there been persistent neurologic deficit, however, surgical evacuation would have been indicated. CONCLUSIONS: Cases of nerve compression caused by a hematoma should be analyzed on the basis of the severity of the neurologic deficit and not on the underlying cause of bleeding. Conservative treatment may be indicated in cases of mild or improving neurologic deficit, but regardless of its etiology, a hematoma that results in severe or worsening neurologic symptoms must be surgically evacuated to prevent permanent nerve damage.

Analgesics, Non-Narcotic↗

PubMed1999

Dural sinus thrombosis endovascular therapy.

Dural sinus thrombosis is a relatively rare, but potentially devastating disease. The problem occurs when there is extensive thrombosis of the intracranial dural sinuses, the outflow channels of venous blood from the brain. If recanalization does not occur, venous hypertension can lead to cerebral edema, infarction, and hemorrhage. Treatment of this disease usually involves anticoagulants, but with mixed results. Endovascular approaches using direct infusion of thrombolytic drugs into the occluded sinuses may result in excellent recanalization and improved patient outcomes.

Cranial Sinuses↗

PubMed1995

Safety and efficacy of percutaneous transluminal angioplasty for intracranial atherosclerotic stenosis.

BACKGROUND AND PURPOSE: Percutaneous transluminal angioplasty (PCTA) is increasingly used to treat extracerebral arterial stenosis. The present study evaluates the safety and efficacy of PCTA treatment of symptomatic intracranial atherosclerotic stenosis. METHODS: A series of 22 vessels in 17 patients were treated with PCTA. All patients had recurrent neurological symptoms referable to the stenotic vessel despite optimal medical therapy. Critical (> 70%) arterial stenosis was confirmed by angiogram, and angioplasty was performed with a 3.0- to 3.5-mm Stealth balloon. RESULTS: The average preangioplasty stenosis (North American Symptomatic Carotid Endarterectomy Trial criteria) was 72 +/- 8% (mean +/- SD), with a significant improvement seen after angioplasty; the best angiographic stenosis (after healing of intimal injury, if any) was 43 +/- 24% (P < .001). Overall PCTA was successful in 82% of the vessels. There were two strokes during angioplasty for a 30-day morbidity rate of 9.1% per treated vessel and 11.7% per case. The other 15 patients were clinically evaluated at 3 and 6 months; all cases were without further events. Restenosis was evaluated in 8 patients (12 vessels) with an angiogram at 6 months showing further improvement compared with the initial post-PCTA stenosis (51 +/- 10% versus 37 +/- 21% [P = .05]). CONCLUSIONS: PCTA may be a beneficial therapy in selected cases of symptomatic intracranial atherosclerotic stenosis. Further study using a randomized trial is needed.

Aged↗

PubMedDate not supplied

Unusual cervical spinal cord toxicity associated with intra-arterial carboplatin, intra-arterial or intravenous etoposide phosphate, and intravenous cyclophosphamide in conjunction with osmotic blood brain-barrier disruption in the vertebral artery.

BACKGROUND AND PURPOSE: When the clinical and radiologic characteristics of an unusual cervical spinal cord complication of intra-arterial (IA) chemotherapy with blood brain-barrier (BBB) disruption in the vertebral circulation are documented. Seven cases are reported and analyzed in search of a pathophysiologic explanation. METHODS: We retrospectively identified 94 patients who received a total of 380 standardized regimens of IA carboplatin, IA or IV etoposide phosphate, and IV cyclophosphamide infusion in conjunction with osmotic BBB disruption of the vertebral artery. We describe seven of those patients in whom unexpected neck pain developed followed by neurologic symptoms primarily in the upper extremities. RESULTS: The symptoms correlated with MR abnormalities (T1 hypointensity, T2 hyperintensity, and unusual contrast enhancement) in the cervical spinal cord, usually involving the gray matter. The neurologic deficits and MR changes were generally transient. One patient who received a flu vaccination 48 hours before the chemotherapy incurred progressive myelitis and expired. CONCLUSION: The pathophysiology of this complication is probably multifactorial but may be related to vascular streaming and an atypical inflammatory toxic reaction to carboplatin and etoposide. The complication has not recurred during a 6-month period following modification of the protocol.

Adolescent↗