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Biomedical subjects

A Gholkar

Publications and source records attributed to A Gholkar.

At least 37 records · Page 2Linked to original sources
PubMed1999

Apolipoprotein E epsilon4 allele, temporal lobe atrophy, and white matter lesions in late-life dementias.

OBJECTIVE: To examine the relationship between the apolipoprotein E (APOE) epsilon4 genotype, medial temporal lobe atrophy, and white matter hyperintensities on magnetic resonance imaging in late-life dementias. DESIGN: Structural magnetic resonance imaging study using T2-weighted and proton density-weighted axial scans and T1-weighted coronal scans. SETTING: Community-dwelling population of elderly patients prospectively chosen from a clinical case register of consecutive referrals to old age psychiatry services. SUBJECTS: Twenty-five subjects with Alzheimer disease (by criteria of the National Institute of Neurological and Communication Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association; mean age, 77.8 years), 22 subjects with dementia with Lewy bodies (consensus criteria; mean age, 77.2 years), and 24 subjects with vascular dementia (by criteria of the National Institute of Neurological Disorders and Stroke and the Association International pour la Recherche et l'Enseignement en Neurosciences; mean age, 76.9 years) were selected. Subjects were well matched for age, sex, duration of illness, and cognitive function. MAIN OUTCOME MEASURES: The APOE genotype was determined using the polymerase chain reaction method, and medial temporal lobe atrophy and white matter hyperintensities (periventricular and deep white matter) were visually rated using standardized scales. RESULTS: In all subjects with dementia, no significant associations were noted between APOE epsilon4 status and medial temporal lobe atrophy (mean score: 0 epsilon4 = 4.5, 1 epsilon4 = 4.5, and 2 epsilon4 = 4.3; P = .90), periventricular hyperintensities (0 epsilon4 = 3.3, 1 epsilon4 = 3.1, and 2 epsilon4 = 2.9; P = .83), and white matter hyperintensities (0 epsilon4 = 5.3, 1 epsilon4 = 4.9, and 2 epsilon4 = 4.9; P = .79). CONCLUSIONS: The APOE epsilon4 allele does not determine medial temporal lobe atrophy or white matter lesions, as measured by magnetic resonance imaging in patients with Alzheimer disease, vascular dementia, or dementia with Lewy bodies. Although APOE epsilon4 may modify the risk for acquiring dementia, this finding provides further evidence that APOE epsilon4 does not influence pathological processes thereafter.

Age Factors↗
PubMed1999

Magnetic resonance imaging differences between dementia with Lewy bodies and Alzheimer's disease: a pilot study.

BACKGROUND: Temporal lobe atrophy on magnetic resonance imaging (MRI) has been suggested as a specific diagnostic marker for Alzheimer's disease (AD). No previous comparison with dementia with Lewy bodies (DLB) has been reported. METHOD: T1-weighted MRI scans were performed on 11 subjects with AD (nine with NINCDS/ADRDA probable AD and two with neuropathologically proven AD) and nine subjects with DLB (four with probable DLB diagnosed by clinical criteria and five with neuropathologically proven DLB). Groups were matched for age, duration of illness and cognitive test score. Two raters, blind to diagnosis and neuropathological findings, measured the volumes of the frontal lobes, temporal lobes, hippocampi, parahippocampal gyri, amygdalae, and caudate nuclei using a computerized volumetric analysis system. Scans were also rated for medial temporal atrophy on a four-point scale by an experienced rater. RESULTS: AD subjects had significantly smaller left temporal lobes and parahippocampal gyri than those with DLB. Medial temporal atrophy was present in 9/11 AD cases (82%) and absent in 6/9 (67%) of DLB cases. Two neuropathologically confirmed cases of DLB had severe medial temporal atrophy; both had concurrent AD-type pathology in the temporal lobe (Braak stage 4). CONCLUSIONS: This pilot study supports the hypothesis that a greater burden of pathology centres on the temporal lobes in AD compared with DLB, except in DLB cases with concurrent Alzheimer pathology. A larger study is needed to confirm these findings and to determine whether MRI has a role in assisting with the clinical differentiation between DLB and AD.

Aged↗
PubMed1999

White matter lesions on magnetic resonance imaging in dementia with Lewy bodies, Alzheimer's disease, vascular dementia, and normal aging.

OBJECTIVES: Alzheimer's disease and vascular dementia are associated with an increase in changes in white matter on MRI. The aims were to investigate whether white matter changes also occur in dementia with Lewy bodies and to examine the relation between white matter lesions and the cognitive and non-cognitive features of dementia with Lewy bodies, Alzheimer's disease, and vascular dementia. METHODS: Proton density and T2 weighted images were obtained on a 1.0 Tesla MRI scanner in patients with dementia with Lewy bodies (consensus criteria; n=27, mean age=75.9 years), Alzheimer's disease (NINCDS/ADRDA; n=28, mean age=77.4 years), vascular dementia (NINDS/AIREN; n=25, mean age=76.8 years), and normal controls (n=26, mean age=76.2 years). Cognitive function, depressive symptoms, and psychotic features were assessed using a standardised protocol. Periventricular hyperintensities (PVHs), white matter hyperintensities (WMHs) and basal ganglia hyperintensities (BGHs) were visually rated blind to diagnosis using a semiquantitative scale. RESULTS: Periventricular hyperintensities were positively correlated with age and were more severe in all dementia groups than controls. Total deep hyperintensities scores (WMHs plus BGHs) were significantly higher in all dementia groups than controls and higher in patients with vascular dementia than those with dementia with Lewy bodies or Alzheimer's disease. In all patients with dementia, frontal WMHs were associated with higher depression scores and occipital WMHs were associated with an absence of visual hallucinations and delusions. CONCLUSION: In common with Alzheimer's disease and vascular dementia, PVHs and WMHs were significantly more extensive in dementia with Lewy bodies than in controls. This overlap between different dementias may reflect shared pathological mechanisms. The link between frontal WMHs and depression and the absence of occipital WMHs and psychotic symptoms has important implications for understanding the neurobiological basis of these symptoms.

Aged↗
PubMed1999

The appearance on MRI of vertebrae in acute compression of the spinal cord due to metastases.

We studied MR images of the spine in a consecutive series of 100 patients with acute compression of the spinal cord due to metastases. All patients had documented neurological deficit and histologically proven carcinoma. MRI was used to localise bony metastatic involvement and soft-tissue impingement of the cord. A systematic method of documenting metastatic involvement is described. A total of 43 patients had compression at multiple levels; 160 vertebral levels were studied. In 120 vertebrae (75%), anterior, lateral and posterior bony elements were involved. Soft-tissue impingement of the spinal cord often involved more than one quadrant of its circumference. In 69 vertebrae (43%) there was concomitant anterior and posterior compression. Isolated involvement of a vertebral body was observed in only six vertebrae (3.8%). We have shown that in most cases of acute compression of the spinal cord due to metastases there is coexisting involvement of both anterior and posterior structures.

Adult↗
PubMed1998

Phase I study of temozolomide in paediatric patients with advanced cancer. United Kingdom Children's Cancer Study Group.

A phase I study of temozolomide administered orally once a day, on 5 consecutive days, between 500 and 1200 mg m(-2) per 28-day cycle was performed. Children were stratified according to prior craniospinal irradiation or nitrosourea therapy. Sixteen of 20 patients who had not received prior craniospinal irradiation or nitrosourea therapy were evaluable. Myelosuppression was dose limiting, with Common Toxicity Criteria (CTC) grade 4 thrombocytopenia occurring in one of six patients receiving 1000 mg m(-2) per cycle, and two of four patients treated at 1200 mg m(-2) per cycle. Therefore, the maximum-tolerated dose (MTD) was 1000 mg m(-2) per cycle. The MTD was not defined for children with prior craniospinal irradiation because of poor recruitment. Plasma pharmacokinetic analyses showed temozolomide to be rapidly absorbed and eliminated, with linear increases in peak plasma concentrations and systemic exposure with increasing dose. Responses (CR and PR) were seen in two out of five patients with high-grade astrocytomas, and one patient had stable disease. One of ten patients with diffuse intrinsic brain stem glioma achieved a long-term partial response, and a further two patients had stable disease. Therefore, the dose recommended for phase II studies in patients who have not received prior craniospinal irradiation or nitrosoureas is 1000 mg m(-2) per cycle. Further evaluation in diffuse intrinsic brain stem gliomas and other high-grade astrocytomas is warranted.

Adolescent↗
PubMed1997

UKCCSG study of accelerated radiotherapy for pediatric brain stem gliomas. United Kingdom Childhood Cancer Study Group.

PURPOSE: Between 1991 and 1994, the United Kingdom Childhood Cancer Study Group (UKCCSG) conducted a multicenter study to assess the efficiency and tolerability of accelerated radiotherapy in children with a diagnosis of poor-prognosis brain stem glioma. METHODS AND MATERIALS: Patients eligible for study were those aged 3-16 years with tumors arising in the pons, medulla, or midbrain, not previously treated with radiotherapy or chemotherapy. Histologic confirmation was not mandatory, but computed tomography or magnetic resonance imaging and clinical findings had to be typical, and patients were selected with short prediagnosis symptom history (<3 months), cranial nerve palsies or long tract signs, and intrinsic diffuse lesions on scanning. The treatment dose was 48.6 Gy in 27 fractions, increased to 50.4 Gy in 28 fractions in January 1992, delivered twice daily (except weekends) with an interfraction interval of at least 8 h. Between January 1991 and July 1994, 28 available patients were recruited: 15 boys and 13 girls with ages ranging between 3 and 13 years (median 6). RESULTS: After treatment, neurologic improvement sustained for a period of at least 6 weeks without steroids was reported in 13 children (46%). On central review of postradiotherapy imaging, 50% of children showed evidence of partial response, but none exhibited a complete response. A further six patients (22%) had stable disease. The median survival time was 37 weeks (8.5 months); 1-year survival was 32%, and 2-year survival 11%. The pattern of relapse was local in all 26 patients who died of their disease; 1 patient had evidence of leptomeningeal seeding. Acute radiation morbidity was minimal, with only three patients (11%) exhibiting mild toxicity. No evidence of radiation-induced necrosis was found radiologically or histologically at postmortem. Ability to withdraw steroids following radiotherapy was the single most important prognostic variable in our study. CONCLUSION: The results of this study are comparable to previous outcomes of studies with conventional and hyperfractionated radiotherapy in poor-prognosis brain stem glioma. The fractionation regimen was shown to be tolerable with an acceptable morbidity profile. However, further research is required to improve the poor prognosis of these unfortunate children.

Adolescent↗
PubMed1997

The role of duplex sonography and angiography in the investigation of carotid artery disease.

Some patients with symptomatic carotid stenoses of greater than 70 % benefit from carotid endarterectomy. This study was designed to compare the accuracy of duplex ultrasound with angiography in assessing the degree of carotid stenosis in 73 patients with symptoms of recent carotid territory ischaemia. Ultrasound was found to be most accurate in the group of patients with normal vessels or mild stenoses (0-29 %) when there was 90 % concordance between ultrasound and angiography. Ultrasound was found to be least accurate in the group of patients with severe stenoses (70-99 %) in whom it was more likely to underestimate than to overestimate the degree of stenosis. Only one patient said to have < 30 % stenosis on ultrasonography had a > 70 % stenosis on IADSA. Our results indicate that patients with normal arteries or mild disease shown by ultrasound have a very small chance of having surgically amenable lesions in the neck. Ultrasound is reliable as an exclusory screening test. However, all other stenoses should also be investigated by catheter angiography if surgery is considered. Taking angiography as the reference, only 52 % of patients with severe stenoses, which might be taken as an indication for surgery, were correctly identified on ultrasonography. Ultrasound alone is a poor technique for identifying patients for surgery and a combination of ultrasound screening with angiography for > 30 % stenoses detected by ultrasound is recommended.

Aged↗
PubMed1997

Subclavian artery stenosis presenting as posterior cerebrovascular events after adjuvant radiotherapy for breast cancer.

Late radiotherapy-induced arteriopathy is recognized as an important cause of cerebrovascular disease in patients treated with radiotherapy, usually for head and neck cancers. This case report is an example of radiotherapy-induced left subclavian artery stenosis, which resulted in serious posterior cerebral circulation events after adjuvant radiotherapy for carcinoma of the left breast. In view of the relatively good long term outlook for this disease, it is important to recognize and consider early medical or surgical intervention of such arterial lesions. In this patient, earlier intensive investigations probably would have prevented disabling iatrogenic morbidity.

Adult↗
PubMed1997

Delayed aneurysm formation following surgery for a giant serpentine aneurysm.

We report a case of a giant serpentine aneurysm of the right middle cerebral artery (MCA) that was treated by total excision of the aneurysm with cerebral blood flow control management. Four years later the patient presented with a three month history of headache and angiograms showed a new aneurysm on a different branch of the MCA which is thought to have been caused by the previous surgical dissection.

Adolescent↗
PubMed1997

Angiography in non-traumatic brain haematoma. An analysis of 100 cases.

PURPOSE: The primary purpose of this project was to study the anatomical characteristics of intracerebral haematoma (ICH) in order to determine features that may negate the need for angiography in some patients. MATERIAL AND METHODS: The study was prospective and designed to investigate the underlying cause of non-traumatic ICH in 100 cases assessed by conventional angiography. Patients were excluded if there was a history of trauma or known pre-existing brain abnormality. All patients were examined with CT and angiography within 4 days of the ictus. RESULTS: Ruptured aneurysms or arteriovenous malformations (AVMs) were diagnosed on the initial angiogram in 49% of cases: 27 AVMs and 22 aneurysms. One case of superior sagittal sinus thrombosis was also detected. Vascular abnormalities were found most frequently in the under-40 age group and in cases in which subarachnoid haemorrhage, intraventricular haemorrhage or extracerebral haematoma accompanied the ICH. The temporal lobe was the most frequent anatomical location (37%). When a temporal lobe haematoma extended into the Sylvian fissure from the inferior pole of the temporal lobe or when it was associated with subarachnoid haemorrhage, structural abnormalities were found in over 90% of cases. CONCLUSIONS: There are groups of patients with ICH in whom the CT features are highly suggestive of AVM or aneurysm rupture. If the initial angiography is negative in these cases, careful follow up by repeat angiography and/or MR imaging is essential. However, potentially treatable abnormalities cannot be excluded with certainty by the distribution of the haematoma on CT alone, even if there is a history of pre-existing hypertension.

Adolescent↗
PubMed1997

Sound movement detection deficit due to a brainstem lesion.

Auditory psychophysical testing was carried out on a patient with a central pontine lesion involving the trapezoid body, who presented with a deficit in sound localisation and sound movement detection. A deficit in the analysis of time and intensity differences between the ears was found, which would explain the deficit in detection of sound movement. The impaired detection of sound movement, due to a lesion interfering with convergence of auditory information at the superior olive, suggests this structure to be critical for human sound movement analysis.

Audiometry, Pure-Tone↗
PubMed1996

Incidental intracranial vascular pathology in patients investigated for carotid stenosis.

The assessment of cervical and cranial carotid arteries for atherosclerotic disease is the second commonest referral for angiography in our neuroradiological department; in 1993 this accounted for approximately 17% of the total cases. This is due to the resurgence of interest in endarterectomy for severe carotid stenosis. Although the degree of stenosis can usually be assessed adequately by duplex Doppler ultrasonography, angiography is still recommended as a preoperative examination. The intracranial vessels are visualised, which we consider important when planning vascular surgery. We present a prospective study of 100 patients referred for angiographic assessment of carotid stenosis. As well as giving information about the carotid bifurcation, angiography showed 9 patients to have aneurysms, 2 arteriovenous malformations and 15 severe intracranial atherosclerosis. We consider these "incidental" findings important for future management and highlight the need for thorough assessment of the intracranial vessels in these patients by angiography.

Adult↗
PubMed1996

Arthrogryposis multiplex congenita and bilateral parietal polymicrogyria in association with the intrauterine death of a twin.

A case of neurogenic arthrogryposis multiplex congenita (AMC) with associated neuronal migration abnormalities is described. A child with neurogenic AMC and developmental delay presented with late onset of seizures. The first trimester of the mother's pregnancy was marked by an episode of gastro-enteritis and the intrauterine death of a twin fetus. Computer tomography (CT) and magnetic resonance (MR) imaging demonstrated abnormal neuronal migration consisting of bilateral parietal polymicrogyria, and an isolated grey matter heterotopia.

Age of Onset↗
PubMed1996

Magnetic resonance angiographic assessment after extracranial-intracranial bypass surgery.

Extracranial-intracranial (EC-IC) bypass operation may be performed to augment the distal cerebral circulation. The bypass patency is usually assessed postoperatively with conventional cerebral angiography. Six patients are reported in whom the bypass patency was assessed using magnetic resonance angiography (MRA): Two had intracavernous carotid aneurysms, three had base of skull tumours encompassing the internal carotid artery, and one had occlusion of the right internal carotid artery with poor collateral reserve as confirmed by an acetazolamide stimulation test. Postoperative conventional cerebral angiography was also obtained in three patients for comparison. The MRA correlated reasonably well with conventional cerebral angiography in showing bypass patency, although conventional cerebral angiography was superior in demonstrating small vessels; MRA has the added advantage of showing the relative flow contribution and flow direction under physiological conditions by using targeted presaturation pulses.

Adult↗
PubMed1995

Cortical blindness during left internal mammary angiography.

Two cases of transient cortical blindness during coronary and graft angiography are described. In both cases, the onset of blindness was immediately preceded by manipulation of a guidewire in the left subclavian artery during attempts to selectively engage the internal mammary artery. Vertebral angiography was performed in the first patient and the appearances were compatible with multiple emboli in the posterior circulation. This patient was anticoagulated with intravenous heparin. His vision recovered within 72 h, but a mild visual agnosia persisted and it was only after nearly 3 weeks that all neurological deficits had resolved. The second patient recovered fully within 15 min. We postulate that emboli occurring as a result of manipulation of the guidewire close to the origin of the left vertebral artery was the cause of the cortical blindness in both these patients, although vasospasm as a contributory factor cannot be excluded. With an increasing need for investigation of patients after coronary artery bypass grafting, angiographers should be aware that selective internal mammary graft angiography may carry a higher than normal risk of neurological complications. The use of a guidewire to manipulate the catheter in the subclavian artery may increase this risk.

Angiography↗