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Biomedical subjects

D B Calne

Publications and source records attributed to D B Calne.

At least 271 records · Page 15Linked to original sources
PubMed1976

Penicillin transport from cerebrospinal fluid.

The passage of penicillin G from cerebrospinal fluid (CSF) was studied by continuous ventriculocisternal perfusion in conscious rabbits. The concentration of penicillin G in the perfusate, collected from the cisterna magna, was 76.5 percent +/- 1.0 (SEM) of that entering the ventricles (having adjusted for normal secretion of CSF). The mean concentration of penicillin G rose 15 percent (p less than 0.005) in the cisternal CSF after probenecid (2 mg per milliliter) was added to the perfusion fluid. We conclude that an active transport system removes penicillin G from the CSF; this mechanism can be inhibited by intraventricular probenecid. Our results are in accord with observations deriving from studies on anesthetized animals given probenecid intravenously or intraperitoneally.

Animals↗
PubMed1976

Studies with bromocriptine. Part 1. "On-off" phenomena.

A dopaminergic agonist, bromocriptine, has been studied in patients with idiopathic parkinsonism complicated by severe "on-off" phenomena induced by levodopa. In a "blind" self-evaluating within-patient comparison, fluctuations in clinical state still occurred when levodopa (with or without carbidopa) was replaced with bromocriptine, but they were significantly reduced in frequency. The observation that on-off phenomena can be induced by bromocriptine complicates interpretation of these episodes in terms of pharmacokinetics of levodopa. There may be variations in receptor sensitivity or alterations in the influence of unidentified neurophysiologic mechanisms that modulate striatal output.

Bromocriptine↗
PubMed1976

Studies with bromocriptine. Part 2. Double-blind comparison with levodopa in idiopathic parkinsonism.

A double-blind crossover study was performed in 12 patients with idiopathic parkinsonism to compare their response to bromocriptine with their response to previous optimal drug treatment, including levodopa. There was a 26 percent overall improvement with bromocriptine; rigidity, tremor, and facial expression showed the greatest response. Seven of eight patients who were taking levodopa at the beginning of the study was taken off the drug completely. Adverse reactions were transient and dose-dependent. Bromocriptine promises to be an effective new therapeutic agent in the treatment of idiopathic parkinsonism.

Aged↗
PubMed1976

Studies with bromocriptine: III. Concomitant administration of caffeine to patients with idiopathic parkinsonism.

Caffeine was administered to six patients with idiopathic parkinsonism in an attempt to potentiate the therapeutic response of bromocriptine, a dopamine (DA) receptor agonist, by inhibition of phosphodiesterase. In a double-blind study at doses of 1,000 mg daily, caffeine failed to enhance the antiparkinsonian action of bromocriptine (40 mg daily) given concomitantly. Although effective in potentiating the action of levodopa and other agonists in animal models of parkinsonism, caffeine is inactive in parkinsonism in man.

Bromocriptine↗
PubMed1975

Idiopathic parkinsonism treated with bromocriptine.

The efficacy and toxicity of bromocriptine, a drug which simulates dopamine, have been studied in twenty-eight patients with idiopathic parkinsonism. A double-blind, within-patient comparison between maximum tolerated doses of bromocriptine (mean 46-9 mg daily) and placebo revealed a substantial and statistically significant therapeutic response to the active drug. Adverse reactions were dose dependent, reversible, and similar to those encountered with levodopa. While taking bromocriptine fourteen patients were able to stop levodopa (with or without carbidopa); in five patients the dose of levodopa was reduced by 54% (mean). Eight patients could not tolerate bromocriptine; one patient failed to comply with prescribed adjustments of dosage.

Aged↗
PubMed1975

Interactions of levodopa with inhibitors of monoamine oxidase and L-aromatic amino acid decarboxylase.

Drug interactions between levodopa, tranylcypromine, and carbidopa have been studied in 4 patients with idiopathic parkinsonism. Pressor responses were induced by a combination of levodopa and tranylcypromine. These hypertensive reactions were inhibited by carbidopa, indicating that they are mediated at the periphery. Very small doses of levodopa induced an improvement in parkinsonism when patients were concomitantly taking carbidopa and tranylcypromine, but adverse reactions were prominent.

Adult↗
PubMed1975

Tardive dyskinesia treated with pimozide.

We have investigated the action of pimozide in tardive dyskinesia induced by prolonged administration of phenothiazines. Improvement was recorded in a double blind study of 18 patients treated with maximum tolerated dosage (mean 18.8 mg/day) for 6 weeks. There was no deterioration in the therapeutic action of pimozide over this time. Parkinsonism and sedation were the main adverse effects. They were corrected by reduction of the dose of pimozide, but often recurred so that further adjustments of dosage were necessary. Our findings support the view that tardive dyskinesia is produced by a disturbance in the balance of central transmitters such that dopaminergic transmission is increased.

Aged↗
PubMed1975

Hypothermic action of bromocriptine.

The body temperature of rats has been studied in a cold environment. In this setting, bromocriptine induced hypothermia. This fall in core temperature was inhibited by pimozide. It was concluded that bromocriptine has a dopamine-like action in areas of the brain concerned with the control of body temperature, as has previously been shown for apomorphine and amphetamine.

Amphetamine↗
PubMed1975

Arterial blood pressure in patients with Parkinson's disease.

The casual arterial blood pressure of 411 patients with Parkinson's disease was compared with that of a representative sample of the general population. The patients were also divided into various sub-groups, and comparisons of blood pressure were made between them. The results provided no support for the widely held belief that blood pressure tends to be low in patients with Parkinson's disease.

Adult↗
PubMed1974

Bromocriptine in Parkinsonism.

Bromocriptine, a drug acting directly upon dopaminergic receptors, has been found to have a significant therapeutic action in a double-blind study of 20 patients with idiopathic Parkinsonism who were already receiving conventional therapy, including levodopa. Neurological deficits improved by almost 20% in severely disabled patients; amelioration of mildly affected patients was about 10%. Adverse reactions were similar to those encountered with levodopa-they were all dose-dependent and reversible. These observations are discussed in relation to certain theoretical advantages which might be expected from a drug which acts directly on dopaminergic receptors.

Aged↗