Search PubMed⌕ Search

Biomedical subjects

C E Turner

Publications and source records attributed to C E Turner.

At least 73 records · Page 4Linked to original sources
PubMed1988

Cytoskeletal involvement in the sequential capping of rat thymocyte surface glycoproteins.

The independent capping of the three major rat thymocyte glycoproteins, the leucocyte-common (L-C) antigen, the leucocyte sialoglycoprotein (LSGP) and Thy-1, was investigated using specific monoclonal antibodies. The capping of each antigen did not require redistribution of the other major surface glycoproteins, and was accompanied by a partial co-capping of the cytoskeletal proteins fodrin and actin, but not of tubulin. A study of the ability of a cell that already possesses one glycoprotein cap to cap a second different glycoprotein showed that this was possible in all cases to varying degrees, the second cap always forming at the same position on the cell surface as the first. Colchicine failed to perturb this observed sequential capping polarity, indicating that microtubules did not direct this second capping event.

Actins↗
PubMed1987

Isolation and initial biochemical characterisation of caps of two major rat thymocyte glycoproteins: evidence for the involvement of a 205 K Con A binding protein and cytoskeletal components in capping.

Two major rat thymocyte surface glycoproteins, the leucocyte-common (L-C) antigen and the leucocyte sialoglycoprotein (LSGP), were induced to cap independently, using the specific monoclonal antibodies OX-1 and W3/13, respectively, and an appropriate fluorescently labeled second antibody layer. The caps were subsequently isolated from detergent extracted cells by a procedure involving gentle shearing. TRITC-phalloidin staining of the isolated caps demonstrated the presence of F-actin within these structures, and lectin-affinity staining after fractionation on SDS polyacrylamide gels revealed the presence of a concanavalin A (Con A) binding protein of relative molecular weight (Mr) 205,000, gp205, in both the L-C antigen and LSGP caps, but absent from the detergent-insoluble residue isolated from unchallenged cells. These results suggest that gp205 may be involved in the association of cross-linked glycoproteins with the cytoskeleton during capping.

Animals↗
PubMed1984

Local anesthetic effects of cocaine and several extracts of the coca leaf (E. coca).

Cocaine and a number of different fractions of a crude ethanol extract of the coca leaf (E. coca) were subjected to a local anesthetic screen using rat tail withdrawal from electric shock. Following an intradermal injection of 0.1 ml of a 2.0% (w.v) solution of cocaine HCl, an immediate response was observed. Two of the coca fractions also produced some local anesthesia. An alkaloidal fraction, containing an equivalent amount of cocaine, produced a maximum effect that was approximately 20% less than that observed with cocaine. The only other fraction producing any effect, a water soluble cocaine-free fraction, showed a maximum response that was approximately 30% of that observed with cocaine.

Anesthetics, Local↗
PubMed1983

Allergenic properties of naturally occurring cannabinoids.

The guinea pig maximization test was used to determine the potential of seven cannabinoids to produce allergic contact dermatitis. delta 9-Tetrahydrocannabinol and cannabinol were found to be extreme (Grade V) sensitizers. Cannabidiol, delta 8-tetrahydrocannabinol, and cannabichromene were moderate (Grade III) sensitizers. Cannabigerol and cannabinol methyl ether were not sensitizers. Most of the cannabinoids were found to be allergenically cross-reactive. Additionally, it was shown that the presence of a free 1'-hydroxyl group was required for sensitization, but not to elicit a response in sensitive animals.

Allergens↗
PubMed1983

Effects of the administration of coca alkaloids on the primary immune responses of mice: interaction with delta 9-tetrahydrocannabinol and ethanol.

The effects of cocaine, its metabolites, and other alkaloids from Erythroxylon coca on the primary immune responses of ICR mice to sheep red blood cells (sRBC) and dinitrofluorobenzene (DNFB) were studied. The Jerne hemolytic plaque assay (PFC) was used to evaluate the humoral immune response to sheep red blood cells, and the delayed type hypersensitivity (DTH) response to DNFB was used to study cellular immune responsiveness. Drugs were given in single daily po doses for 5 consecutive days beginning on the day of immunization or 3 days prior to and on Days 3 and 4 after immunization. Inhibition of both PFC and DTH responses occurred at doses of 15 to 60 mg/kg of cocaine and was greatest when fed during immunization. Five other alkaloids also suppressed the PFC and/or DTH response. Cocaine was more suppressive than the six other alkaloids tested. Ethanol (5 g/kg) did not suppress the DTH response and only marginally suppressed the PFC response. delta 9-THC inhibited the PFC response at doses of 10 mg/kg and marginally suppressed the DTH response at doses of 30 mg/kg, but not at other doses ranging from 10 to 90 mg/kg. Coadministration of 5 g/kg ethanol and 15 mg/kg cocaine resulted in 50% antagonism of effects of cocaine on the PFC response and complete antagonism of the suppression of the DTH response, but only if these substances were given during the period of immunization. Like ethanol, delta 9-THC also abolished the inhibitory effects of cocaine on the PFC and DTH response but only if coadministered during the period of immunization. Coadministration of ethanol and delta 9-THC resulted in synergistic inhibition of both DTH and PFC responses.

Alkaloids↗
PubMed1983

Effect of cannabichromene on hepatic microsomal enzyme activity in the mouse.

1. Pretreatment with a Cannabis constituent, cannabichromene (CBC), i.p., had no effect on in vitro hepatic microsomal enzyme activity compared to a known inhibitor of these systems, SKF 525-A. 2. The results indicate that the previously reported CBC potentiation of CNS depressant-induced hypnosis is not mediated by the hepatic microsomal enzyme system.

Aminopyrine N-Demethylase↗
PubMed1983

Gastrointestinal pseudo-obstruction due to pheochromocytoma.

A patient with a pheochromocytoma is described whose intermittent symptoms and clinical findings suggested upper gastrointestinal obstruction. The nature of this illness proved elusive until severe paroxysmal hypertension was noted during a periodic examination. The case report and gastrointestinal x-rays confirm the intermittent nature of both the gastrointestinal motility disturbances and the hypertension. The resolution of the gastrointestinal symptoms during a 3-years postoperative follow-up confirms the association. Gastrointestinal symptoms are rarely the predominant manifestation of pheochromocytoma, but recognition of this association may permit earlier diagnosis.

Adrenal Gland Neoplasms↗
PubMed1983

The 17th Annual Harry G. Armstrong Lecture. Cannabis: the plant, its drugs, and their effects.

Marijuana is not a plant. It is a crude drug made from the Cannabis plant. Many other crude drugs are also made from this plant. Their chemical composition varies with the plant parts used in producing the particular drug. This paper describes the chemical composition of Cannabis, the uses to which these chemicals are put in the manufacture of crude drugs, and the effects of these drugs.

Cannabinoids↗
PubMed1982

Biological effects of nonalkaloid-containing fractions of Erythroxylon coca.

Water soluble nonalkaloid fractions of Erythroxylon coca were screened in mice for their effects on oxygen utilization and central nervous system (CNS) activity. The fractions were screened in dogs for cardiovascular, blood glucose, and respiratory changes. No CNS effects were demonstrated in mice; however, there was a reduction in the oxygen utilization rate. Intravenous administration of the extract to dogs produced hyperglycemia, a reduction in heart rate, and a decrease in blood pressure. No substantial change in the respiratory rate and tidal or minute volumes were observed.

Animals↗
PubMed1982

Comparative lethality of coca and cocaine.

The 24 hour lethal effects of cocaine were compared to those of a crude ethanol extract of the coca leaf (Erthroxylon coca) in male, Swiss mice. Various doses of cocaine HCl and coca leaf extracts suspended in a Tween 60, Arlacel 83, and distilled water vehicle were injected IP into groups of 10 mice. The LD50 for cocaine was 95.1 mg/kg. The LD50 for the coca extract was 3450 mg/kg. The LD50 of the extract based on its cocaine content was 31.4 mg/kg. The results clearly indicate that the coca leaf contains constituents other than cocaine that can contribute to a toxic effect of the plant.

Animals↗
PubMed1981

Determination of cannabidiol in plasma by electron-capture gas chromatography.

A procedure was developed for the analysis of cannabidiol (CBD) in blood plasma. Tetrahydrocannabidiol was used as an internal standard and was added prior to extraction. The plasma extracts were derivatized with pentafluorobenzyl bromide and the produce purified on a mini-column of Florisil. The pentafluorobenzyl derivatives were then analyzed by gas chromatography on a 5% OV-225 column using an electron-capture detector. A detection limit of 50 ng CBD per ml of plasma was observed. The procedure was used to study the plasma level of CBD after its oral and intravenous administration to monkeys.

Animals↗
PubMed1981

Comparative stimulus properties of two fractions of the coca leaf (E. coca).

Male and female Wistar rats were trained to discriminate 5.0 mg/kg cocaine from 2.0 ml/kg saline using a two-bar food reinforcement (FR 30) drug discrimination paradigm. Once discrimination behavior had stabilized the subjects were tested (in extinction) with several doses of two different fractions of the coca leaf and four doses of cocaine HCl (1.0, 2.5, 7.5, 10 mg/kg). The fractions were prepared by extracting powdered coca leaves with 95% ethanol and then partitioning the residue between chloroform and water. Two doses of the water fractions (480, 960 mg/kg) and five doses of the chloroform fraction (7.5, 15, 30, 60 120 mg/kg) were tested. The water fractions was devoid of cocaine while the five doses of the chloroform fraction contained cocaine equivalent to 0.4, 0.83, 1.65, 3.3 and 6.6 mg/kg, respectively, as determined by gas chromatographic analysis. The 2.5, 7.5, and 10.0 mg/kg cocaine doses generalized to cocaine. The 1.0 mg/kg dose of cocaine generalized to saline. The water fraction at 480 mg/kg generalized to saline; however following pretreatment with the 960 mg/kg dose of this fraction, the animals failed to respond. The two largest doses of the chloroform fraction (60 and 120 mg/kg) generalized to cocaine while the other three doses did not. The 7.5 mg/kg generalized to saline; the 15 and 30 mg/kg doses engendered an intermediate level of responding on both the cocaine and saline lever.

Animals↗