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Biomedical subjects

W J Hamilton

Publications and source records attributed to W J Hamilton.

At least 19 recordsLinked to original sources
PubMed1996

The clinical significance of extracellular matrix in gangliogliomas.

Based on in vitro studies which demonstrate that collagen IV and laminin inhibit the proliferation and invasiveness of glioma cells, we investigated the clinical significance of these extracellular matrix proteins (ECM) in patients with gangliogliomas, tumors in which ECM is often a prominent feature. Our study compared the relative presence and deposition pattern of collagen IV and laminin in 19 gangliogliomas and in 18 gliomas without ganglion cell differentiation (8 low-grade astrocytomas, 7 anaplastic astrocytomas, and 3 anaplastic mixed gliomas). We also examined whether the presence of collagen IV and laminin correlated with other features often observed in gangliogliomas, including perivascular lymphocytic inflammation, granular bodies, microcalcification, and subarachnoid extension, and whether any of these features were associated with the patient's clinical course. Significant deposition of collagen IV and laminin was found in 9 gangliogliomas (47%), but in none of the other gliomas. The presence of these extracellular proteins in gangliogliomas correlated with both perivascular inflammation (P = 0.003), and involvement of the leptomeninges by tumor (P = 0.008). The duration of symptoms prior to surgical resection was significantly longer for patients whose tumors showed extracellular deposition of collagen IV and laminin than for patients whose tumors lacked deposition of these proteins (mean 13.7 vs 5.1 years; P = 0.02). In addition, the duration of symptoms was significantly longer for patients whose tumors exhibited perivascular inflammation than for patients whose tumors displayed little or no perivascular inflammation (mean 14.8 vs 4.8 years; P = 0.01). These findings suggests that collagen IV and laminin and perivascular inflammation are related to the indolent behavior of gangliogliomas.

Adolescent↗
PubMed1995

Outcome after stereotactic thalamotomy for dystonia and hemiballismus.

The outcome after single or staged stereotactic thalamotomies in 17 patients with dystonia and 2 patients with hemiballismus is reviewed. All patients were severely disabled by their movement disorders despite optimal pharmacological therapies. Eight of the patients with dystonia (47%) showed moderate improvement immediately after the procedures. Six of these eight patients maintained their improvement, and two other patients with dystonia improved significantly, during the follow-up period (mean, 37.6 mo). The long-term outcome was better in patients with secondary dystonia (50% moderately or markedly improved at a mean of 41.0 mo) than in patients with primary dystonia (43% moderately or markedly improved at a mean of 32.9 mo). Excellent control was achieved in both of the patients who underwent thalamotomies for hemiballismus.

Adolescent↗
PubMed1995

Outcome after stereotactic thalamotomy for parkinsonian, essential, and other types of tremor.

A better understanding of the mechanisms underlying movement disorders, coupled with refinements in surgical technique, has led to a resurgence of interest in the surgical treatment of patients with tremor. We retrospectively analyzed the outcomes of 60 patients (62 patient sides) with medically intractable tremor who underwent stereotactic thalamotomy. Of these 60 patients, 42 had Parkinson's disease (of whom 2 patients underwent bilateral surgery for a total of 44 patient sides), 6 had essential tremor, 6 had cerebellar tremor, and 6 had post-traumatic tremor. The patients received follow-up for as long as 13 years (mean, 53.4 mo) after their operations. At the most recent follow-up visit, 86% of the patients with Parkinson's disease, 83% of the patients with essential tremor, 67% of the patients with cerebellar tremor, and 50% of the patients with post-traumatic tremor had cessation of or moderate-to-marked improvement in their contralateral tremor, with a concomitant improvement in function. The mean daily dose of levodopa for those patients preoperatively taking levodopa (n = 35) was reduced by approximately 156 mg at a mean of 53.4 months after thalamotomy. Immediate postoperative complications were common, occurring in 58% of patients. The most common complications were contralateral weakness (34%), dysarthria (29%), and confusion (23%). These complications generally resolved rapidly during the postoperative period.

Adult↗
PubMed1993

Disbudding of red deer stag calves to prevent antler growth.

Red deer stag calves aged five to seven months were disbudded with a standard cattle disbudding iron as a means of preventing antler growth and development. Two sizes of iron, one 2.2 cm in diameter and one 1.5 cm in diameter, were compared at disbudding in November or January. Disbudding in November and January with the 2.2 cm iron had success rates of 97 per cent and 92 per cent, respectively. Treatment with the 1.5 cm iron was less effective at both times. There was no significant difference between the liveweights of the treated groups and a non-disbudded control group at turnout in the spring or at slaughter in November when the stags were 16 months of age.

Anesthesia, Local↗
PubMed1990

Tyrosine hydroxylase-immunoreactive neurons in the temporal lobe in complex partial seizures.

The anterior mesial portion of the temporal lobe removed from 16 patients who underwent surgery for the treatment of complex partial seizures was found to contain tyrosine hydroxylase-immunoreactive neurons. The distribution of these neurons was correlated with the underlying neuropathological features. Ammon's horn sclerosis was present in 8 patients; a ganglioglioma, in 7 patients; and an infarction in the distribution of the middle cerebral artery, in 1 patient. Tyrosine hydroxylase-immunoreactive neurons were found in Ammon's horn of 6 of the 8 patients with Ammon's horn sclerosis, and in the subiculum and entorhinal cortex of all 8 patients with the same pathology. None of these neurons were found in Ammon's horn of the 7 patients with a ganglioglioma, but were found in the subiculum of 5 of the 7 patients and in entorhinal cortex of all 7 patients. Tyrosine hydroxylase immunoreactivity was also studied in 13 control autopsy specimens. No tyrosine hydroxylase-immunoreactive neurons were found in Ammon's horn or the subiculum of any of the control specimens, but were found in the entorhinal cortex of 6 of the 13 specimens. The tyrosine hydroxylase-immunoreactive neurons in the mesial portion of the temporal lobe of patients with complex partial seizures may contribute to the increased levels of tyrosine hydroxylase found in neurochemical studies of specimens taken at temporal lobectomy.

Adolescent↗
PubMed1989

Diagnosis of pregnancy and prediction of fetal age in red deer by real-time ultrasonic scanning.

Sixteen pregnant red deer hinds were scanned using real-time ultra sound at regular intervals during the first 150 days of pregnancy. In the early stages of pregnancy, an intra-rectal linear array transducer was used but later in pregnancy the hinds were scanned externally with a sector scanner. Pregnancy was determined from 30 days of gestation by intra-rectal scanning, and from 50 days by external scanning. With advancing age the size of the fetus increased, and linear regressions of size on age gave residual standard deviations of 0.508 days for head diameter and 0.506 days for trunk diameter. It is concluded that this technique can be used to determine pregnancy with a high degree of accuracy from 30 days of gestation and to predict calving date from fetal measurements within the range 1.5 cm to 7 cm for head diameter or 0.5 cm to 8 cm for trunk diameter, corresponding to a fetal age range of 35 to 150 days.

Animals↗
PubMed1984

Irreversible neurologic complications of metrizamide myelography.

Metrizamide, a major contrast agent for myelographic procedures, has rarely been reported to cause irreversible neurologic complications. The major transient neurologic alterations include neuropsychological reactions, generalized tonic-clonic seizures, and headaches. Two cases of irreversible spinal neurologic deficits resulting from metrizamide myelography are reported, and the factors that may increase the risks of complications in metrizamide myelographic studies are discussed, including preexisting dehydration, patient positioning, and the concentration of contrast agent.

Adult↗
PubMed1983

Treatment approaches in Gilles de la Tourette syndrome.

The neurological disorder Gilles de la Tourette syndrome is most often treated with the receptor blocker haloperidol, which also produces multiple side-effects, including the risk for tardive dyskinesia. In placebo control double-blind studies, two other neuroleptic drugs, fluphenazine and trifluoperazine, were found to be as efficaceous as haloperidol, but with fewer side-effects. In other studies, clonidine was shown to be equally efficaceous with haloperidol, but did not produce adverse central nervous system side-effects. To treat the extrapyramidal side-effects accompanying the treatment of Tourette syndrome with neuroleptic agents, amantadine and benztropine were compared in a crossover study. It was demonstrated that amantadine is a superior agent in treating the side effects of haloperidol treatment in Tourette syndrome. The use of lithium was without significant action upon lessening the tics of Tourette syndrome.

Amantadine↗
PubMed1981

Parkinson's disease.

Explore the source record for details and available documents.

Antiparkinson Agents↗
PubMed1980

Dictyocaulus infection in farmed red deer (Cervus elaphus).

Post mortem examination of red deer calves on a deer farm situated on hill ground in north-east Scotland revealed infection by a lungworm morphologically similar to Dictyocaulus viviparus. Trials were conducted to monitor the natural development of D viviparus infection in red deer, to investigate the value of a commercial lungworm vaccine and to evaluate methods of treating clinical cases. The findings indicate that the syndrome may be less apparent in red deer than it is in cattle, protection might be gained by vaccination and that housing and medication provide useful therapy. The extent of clinical disease is likely to depend on the general health, bodily condition and nutritional status of the animals versus the weight of infection acquired from the pasture. However, various factors can affect both sides in this confrontation.

Animals↗
PubMed1980

The localization of sodium and calcium to schwann cell paranodal loops at nodes of Ranvier and of calcium to compact myelin.

High-voltage electron microscopy (HVEM) has been used to determine the distribution of cationic precipitates in myelinated axons resulting from the application of two cytochemical techniques: a direct osmium pyroantimonate treatment for precipitating Na+, Ca2+ and Mg2+; and a 5 mM Ca2+ inclusion procedure (Oschman & Wall) for imparting electron density to Ca2+ binding sites. Electron probe wavelength spectroscopy was then used on semi-thick tissue sections to identify the species of ions present in the following regions: Schwann cell paranodal loops, axoplasm at the node, compact myelin and extracellular matrix. With these combined procedures we were able to localize elevated concentrations of both Na+ and Ca2+ to cytoplasmic compartments of the Schwann cell paranodal loops, as well as to detect the presence of Ca2+ at elevated levels in compact myelin. The involvement of the Schwann cell paranodal loops in providing a source and/or sink for Na+ involved in impulse conduction is suggested by these results, and the significance of such a role is discussed. A role for Ca2+ in the formation and stabilization of myelin lamellae is also suggested.

Animals↗