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Biomedical subjects

B C Jones

Publications and source records attributed to B C Jones.

At least 91 records · Page 5Linked to original sources
PubMed1990

Further characterization of LSxSS recombinant inbred strains of mice: activating and hypothermic effects of ethanol.

Lines of mice selected for differential initial sensitivity to the anesthetic effects of ethanol also differ in their locomotor responses to lower doses of ethanol. Sixteen recombinant inbred strains of mice derived from long-sleep (LS) and short-sleep (SS) selected lines as well as inbred LS and SS mice were used in a genetic correlational study to investigate possible associations between high-dose and low-dose indices of initial sensitivity to ethanol. Measurements of high-dose (4.1 g/kg) effects of ethanol were hypothermia, sleep time, and blood ethanol content at regaining of righting response, and the index of low-dose (1.875 g/kg) sensitivity was distance traveled during a 5-min period immediately following intraperitoneal injection with ethanol. The results indicated wide genetic variation in hypothermia and ethanol-induced locomotor activation in a manner consistent with polygenic influence. Furthermore, correlations between low-dose locomotor activity and hypnotic dose effects tended to be low and nonsignificant, indicating independence of inherited mechanisms underlying high- and low-dose ethanol sensitivity.

Alcoholism↗
PubMed1989

Synthesis and biological evaluation of some phosphate triester derivatives of the anti-cancer drug araC.

A number of novel phosphate triester derivatives of the anti-cancer nucleoside analogue araC have been prepared by a rapid 2-step procedure, not necessitating prior sugar protection. Spectroscopic and lipophilicity data have been collected on these compounds. An in vitro assay indicated inhibition of thymidine incorporation by mammalian epithelial cells, by each of these compounds, in the range 3-300 microM. Moreover, the degree of inhibition showed a close correlation to chemical structure; in particular, there was a clear relationship between inhibition of thymidine incorporation and log(P). These results are consistent with cellular penetration by the intact phosphate triesters and intracellular action by an unspecified mechanism. Triethyl phosphate is inactive under the conditions of the test.

Animals↗
PubMed1988

Central muscarinic cholinergic influences on ethanol sensitivity in long-sleep and short-sleep mice.

Sensitivity to the hypnotic effects of ethanol was increased selectively by central administration of muscarinic agonists. Carbachol or oxotremorine, but not nicotine, i.c.v., enhanced hypnotic sensitivity to ethanol markedly, as measured by blood ethanol concentration at loss or righting response, in short-sleep (SS) but not long-sleep (LS) mice. Likewise, the acetylcholinesterase inhibitor, neostigmine, i.c.v., differentially enhanced hypnotic sensitivity to ethanol in these mouse lines. LS and SS mice were equally sensitive to the hypothermic effects of carbachol, neostigmine or oxotremorine i.c.v. The muscarinic antagonists, atropine or pirenzepine, i.c.v., were without effect on ethanol sensitivity, but these compounds antagonized muscarinic agonist-enhanced ethanol sensitivity in SS mice effectively. Pirenzepine, and M1 selective antagonist, produced a parallel shift in the oxotremorine dose-response curve, indicating that the enhanced hypnotic sensitivity to ethanol may be due to interaction of oxotremorine with M1 muscarinic receptors. This possibility was supported by the finding that atropine and pirenzepine which are known to have comparable affinities for M1 but not M2 receptors, had comparable potencies in antagonizing the action of oxotremorine or neostigmine. The results suggest that LS and SS mice differ genetically in neuronal processes activated by specific muscarinic agonists and are consistent with the hypotheses that ethanol acts in part via membrane receptor coupling to intracellular processes known to mobilize intracellular Ca++.

Animals↗
PubMed1986

Differential immune response in two handled inbred strains of mice.

C57BL/10J and BALB/cJ mice, outfostered at birth to C3H/2Ibg dams were subjected to handling on days 1 through 20 of life. Their plaque forming cell (PFC) response to sheep red blood cells as adults on day 5 post-immunization was compared to the PFC response in non-handled control mice. The PFC response of handled C57BL/10J mice was significantly suppressed compared to the PFC response in non-handled mice while the response of the handled and non-handled BALB/cJ mice was not significantly different.

Animals↗
PubMed1986

A comparison of the metabolic fate of phenol, phenyl glucoside and phenyl 6-O-malonyl-glucoside in the rat.

The metabolic fates of 14C-phenol and its model plant conjugates 14C-phenyl glucoside and 14C-phenyl 6-O-malonyl-glucoside have been compared following equimolar oral dosing to rats (1.2 mg phenol/kg). Rapid excretion of radioactivity in the urine (at least 80% within 24 h) was observed with each compound. Phenol was eliminated as expected mainly as phenyl sulphate (68%) and partly as phenyl glucuronide (12%). The excretion profile for phenyl malonyl-glucoside was very similar to that of phenol, with the exception that small amounts of phenyl glucoside and phenyl malonyl-glucoside were excreted. In contrast, a major part of the dose of phenyl glucoside was eliminated unchanged. The value of metabolism studies in the assessment of the toxicology of xenobiotic metabolites derived from plants is discussed.

Animals↗
PubMed1985

Spontaneous hemothorax in a patient with Osler-Weber-Rendu disease.

We have reported a case of spontaneous hemothorax as a rare complication of Osler-Weber-Rendu disease (hereditary hemorrhagic telangiectasia). Because of the possibility of confusion with pulmonary infarction and its attendant treatment with anticoagulants, physicians should be aware of possible hemothorax in Osler-Weber-Rendu disease.

Arteriovenous Malformations↗
PubMed1980

Enhanced megakaryocyte repopulating ability of stem cells surviving 5-fluorouracil treatment.

The effect of 5-fluorouracil treatment of donor mice on the capacity of transplanted bone marrow to produce megakaryocytes in the spleens of lethally irradiated recipients has been examined. At both 10 and 13 days after transplantation, the spleens of recipients of 5-fluorouracil treated bone marrow had significantly more megakarocytes per unit area of spleen section than recipients injected with an equivalent number of spleen colony forming units from normal bone marrow. It is suggested that such treatment may provide a sensitive in vivo system for the investigation of endogenous factors influencing megakaryocyte progenitor proliferation. The results are consistent with the concept of stem cells being heterogeneous with respect to self-renewal capacity.

Animals↗
PubMed1980

Stability of cefazolin sodium admixtures in plastic bags after thawing by microwave radiation.

The effect on antibiotic stability of thawing, with microwave radiation, cefazolin sodium admixtures frozen in polyvinyl chloride minibags was studied. Two brands of cefazolin sodium (Ancef and Kefzol) were reconstituted and placed in 50-, 100- and 250-ml polyvinyl chloride minibags of 5% dextrose in water or 0.9% sodium chloride. The resulting solutions were assayed for antibiotic stability, using an agar disk diffusion technique, and for pH. The solutions were then stored at -20 degrees C for 48 hours, thawed to room temperature in a microwave oven, and kept at room temperature for four hours, after which they were reassayed for potency and pH. The results indicated that after the freeze-thaw process, the cefazolin sodium minibag admixtures retained at least 90% of their initial antimicrobial activity. The minimal pH changes could not be related to changes in antimicrobial activity, and no color changes could be detected visually. Using a microwave oven can greatly reduce thawing time of antibiotic admixtures. To maintain solution stability and prevent accidents, it is important to calibrate the oven, avoid solution overheating, and observe full precautions in oven operation.

Biological Assay↗
PubMed1976

Acute effects of morphine and chlorpromazine on the acquisition of shuttle box conditioned avoidance response.

Morphine sulfate, 0.25-24.0 mg/kg, or chlorpromazine hydrochloride, 0.0625-4.0mg/kg were administered subcutaneously to naive rats 30 min prior to the start of massed-trials conditioned avoidance response (CAR) testing. The graded doses of both drugs were applied in each of three CAR task difficulty levels created by manipulation of the duration of conditioned and unconditioned stimuli, intertrial interval and shock intensity. Chlorpromazine, in a dose-related manner, caused a decrement in CAR acquisition in all tasks. Morphine, in comparison, produced a biphasic dose response. For a given task difficulty, low doses of morphine enhanced acquisition, whereas higher doses inhibited acquisition. With increasing task difficulty, relatively larger doses of morphine were required to inhibit or facilitate acquisition of CAR. These results emphasize the need to consider not only drug dosage levels, but also the interaction of task difficulty in the application of drugs in learning paradigms.

Animals↗
PubMed1976

The interaction of delta9-tetrahydrocannabinol with cholinomimetic drugs in an agonist-antagonist paradigm.

In rabbits, i.v. delta9-tetrahydrocannabinol (delta9-THC) at 0.5 mg/kg was challenged with i.v. arecoline (0.025 mg/kg), nicotine (0.02 mg/kg) or physostigmine (PHYSO, 0.05 mg/kg), and observations were made on quantified EEG and behavior. The cholinomimetics effectively reversed the cortical and hippocampal EEG alterations induced by delta9-THC. Arecoline and PHYSO temporarily reversed the behavioral-sedative effects of delta9-THC whereas the combination of delta9-THC with nicotine produced behavioral collapse preceded by behavioral disturbance.

Animals↗