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Biomedical subjects

D L Davidson

Publications and source records attributed to D L Davidson.

At least 19 recordsLinked to original sources
PubMed1997

Repeated daily cocaine alters subsequent cocaine-induced increase of extracellular dopamine in the medial prefrontal cortex.

Male Sprague-Dawley rats that were naive or that had been treated with five daily saline or cocaine injections (15 mg/kg i.p.) were subsequently challenged with an injection of cocaine, and extracellular dopamine content in the medial prefrontal cortex (mPFC) was measured using in vivo microdialysis. Cocaine challenge increased extracellular dopamine levels from base line in all three groups of rats, but the augmentation was significantly reduced in the cocaine-pretreated group, compared with the saline-pretreated group. In contrast, mPFC dopamine levels were not different among groups after challenge with systemic d-amphetamine. To test whether repeated cocaine treatment led to altered releasability of dopamine from mPFC terminals, challenge with KCI (10, 30 or 100 mM) or d-amphetamine (3, 30 or 300 microM) was made via infusion through the dialysis probe into the mPFC. No differences in dopamine levels were found between treatment groups for either drug at any dose. To determine whether the effects of cocaine were mediated by local actions within mPFC dopamine terminals, a cocaine challenge was administered through the microdialysis probe (1, 10 or 100 microM). In contrast to the systemic cocaine challenge, local infusion of cocaine elicited a significant increase in daily cocaine-pretreated rats, compared with saline-pretreated controls, at the lowest dose tested, with no differences at the higher two doses. In summary, daily cocaine-pretreated rats demonstrated a suppressed mPFC dopamine response to subsequent systemic, but not local, cocaine challenge. The results suggest that this apparent tolerance is not due to altered releasability of dopamine from mPFC terminals and may rely on altered afferent regulation of mesocortical dopamine neurons.

Amphetamine↗
PubMed1994

Check chains.

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Animals↗
PubMed1994

The cost of epilepsy in patients attending a specialist epilepsy service.

Epilepsy is a common disability, especially in young adults, and, as the costs to the community are likely to be high, estimates are required to plan health and community care. The neurological unit of Dundee Royal Infirmary provides an epilepsy clinic for the Tayside region (population 300,000) and in 1991 the records of over 303 patients were computerized using the Epicare system developed by Sanofi-Winthrop. It was calculated that the total state expenditure on care was 662,919 pounds (2188 pounds/head) in 1991. The direct health costs were obtained by reviewing database entries and medical records and were estimated to be 159,192 pounds (24%), including 77,171 pounds for drugs, 64,750 pounds for hospital care and 17,271 pounds for general practice consultations. The cost of welfare payments was 503,728 pounds/year (76%) (4419 pounds/recipient). The transfer payments to patients with epilepsy greatly exceed the costs of health care and any management strategy which improves the prospects for employment and independence of people with epilepsy is likely to produce significant fiscal benefits for both the individual and the state.

Adolescent↗
PubMed1994

A multicentre comparative trial of sodium valproate and carbamazepine in adult onset epilepsy. Adult EPITEG Collaborative Group.

The long-term efficacy and safety of sodium valproate and carbamazepine in adult outpatients with newly diagnosed primary generalised or partial and secondarily generalised seizures were compared in a randomised, open, multicentre study at 22 neurology outpatient clinics. Patients were randomised to oral sodium valproate (Epilim EC enteric coated 200 mg tablets twice daily, n = 149) or oral carbamazepine (100 mg twice daily increasing to 200 mg twice daily in week 2, n = 151) and followed up for three years. If clinically necessary, dosages were regularly increased until seizures were controlled or toxicity developed. Sodium valproate and carbamazepine controlled both primary generalised and partial seizures equally effectively overall. Significantly more patients on sodium valproate than carbamazepine (126/140 (90%) v 105/141 (75%), p = 0.001) remained on randomised treatment for at least six months. Skin rashes occurred significantly more often in carbamazepine recipients than in sodium valproate recipients (11.2% v 1.7%, p < 0.05) and carbamazepine was associated with a higher withdrawal rate because of adverse events (15% v 5% on sodium valproate) in the first six months of treatment. There was no difference between the drugs in the rate of withdrawal because of poor seizure control at any stage, regardless of seizure type. At the end of the three year trial period, over 70% of the available patients were still on randomised treatment or had recently stopped treatment after achieving full seizure control. Sodium valproate and carbamazepine were both associated with a high degree of overall seizure control regardless of seizure type and both have good long-term tolerability in adult patients with newly diagnosed epilepsy. Recommendations are made for a higher initial dosage regime for sodium valproate in partial seizures.

Administration, Oral↗
PubMed1992

Western blotting analysis in patients with MS using human brain vessels as antigen.

Serum samples from patients suffering from multiple sclerosis, other neurological diseases and normal controls were screened by "western blotting" for antibody directed against proteins of human brain vessels purified from a post mortem brain. A small number of sera contained autoantibodies against some of the proteins of the brain vessels, particularly in patients suffering from MS, epilepsy and migraine. The significance of these results is discussed.

Antibody Specificity↗
PubMed1989

Parathyroid hyperplasia associated with thymoma.

The case of a 65 year old female with myasthenia gravis and hypercalcaemia is presented. Failure of medical control of the myasthenia necessitated thymectomy at which time parathyroid exploration was also carried out. This revealed parathyroid hyperplasia and a thymoma. This association has not been previously documented in the literature.

Aged↗
PubMed1988

Adoptive immunotherapy of human cancer using low-dose recombinant interleukin 2 and lymphokine-activated killer cells.

The adoptive transfer of recombinant-methionyl human interleukin 2 (rIL-2)-activated autologous peripheral blood mononuclear lymphokine-activated killer (LAK) cells to cancer patients is being evaluated as an alternative to conventional cancer therapy. We have independently developed an alternative regimen to previously reported adoptive immunotherapy protocols using rIL-2 and LAK cells which features the prolonged administration of low-dose rIL-2 (30,000 units/kg) and an automated, entirely enclosed system of peripheral blood cell procurement, culture, harvest, and reinfusion of activated cells. The cell culture system was tested with a murine tumor model in which LAK cells generated in plastic culture bags were reinfused into tumor-bearing mice. Tumor regression was as effective with cells activated in the bags as in conventional culture flasks. Twenty-eight cancer patients were treated for 5 consecutive days with low-dose rIL-2, followed by leukapheresis, infusion of LAK cells, and prolonged IL-2 administration. At least 50% tumor regression was observed in 46% of all patients treated. These data imply that human peripheral blood mononuclear cells retain fully their capacity for rIL-2-induced activation and effector cell function under this alternative approach, and further, that a low-dose rIL-2 regimen with markedly reduced toxicities can be as effective as high-dose rIL-2 regimens if low-dose rIL-2 is given for a prolonged period of time following LAK cell infusion.

Adult↗
PubMed1987

The effective evaluation of thyroid status in patients on phenytoin, carbamazepine or sodium valproate attending an epilepsy clinic.

To assess the most efficient means of monitoring thyroid status in an epilepsy clinic, total thyroxine (T4), free thyroxine stimulating hormone (TSH) were measured in 71 adult patients treated long-term with either phenytoin (DPH), carbamazepine (CBZ) or sodium valproate (VAL). Twenty-seven patients with one or more abnormal thyroid hormone results were further investigated by a thyrotrophin releasing hormone (TRH) test and clinical assessment. T4 was found to be normal in 85% on VAL, 40% on CBZ and 39% on DPH. FT4 was normal in more patients, namely 95% on VAL, 70% on CBZ and 65% on DPH. The TRH tests indicated that FT4 was the most efficient screening test for hypothyroidism in this epileptic population. We estimate that the use of FT4 alone as a screening test would have reduced by 60% the number of TRH tests required.

Adult↗