Search PubMed⌕ Search

Biomedical subjects

G L Jones

Publications and source records attributed to G L Jones.

At least 109 records · Page 6Linked to original sources
PubMed1978

Spin-label study of phenothiazine interactions with erythrocyte ghost membranes: a possible membrane-mediated antisickling action.

Erythrocyte membrane alterations by 11 phenothiazine derivatives known to inhibit the sickling phenomenon in vitro have been evaluated in ghosts by the spin-labeling technique. Four sulfydryl-reactive spin labels were employed: 4-maleimido-2,2,6,6-tetramethylpiperidinooxyl; 4-(2-iodoacetamido)-2,2,6,6-tetramethylpiperidinooxyl; 3-[(2-iodoacetamido)methyl]-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl; and 3-(maleimidomethyl)-2,2,5,5-tetramethyl-1-pyrrolidiny-loxyl. The latter spin label was judged most useful since its spectrum was sensitive to subtle perturbations by drugs spanning a considerable potency range. An increase in spin-probe immobilization was induced by each drug with approximate relative potencies given by the order: desmethylchlorpromazine congruent to thioridazine congruent to fluphenazine congruent to prochlorperazine congruent to trifluoperazine greater than acetophenazine congruent to triflupromazine congruent to chlorpromazine greater than promazine greater than promethazine greater than perphenazine. This order correlates (P less than .01) with their antisickling potency in vitro.

Antisickling Agents↗
PubMed1976

Dynamics of adenosine-3', 5'- monophosphate transfer among mother, fetus, and amniotic fluid in the rhesus monkey.

Cyclic AMP exchange among the mother, amniotic fluid, and fetus was studied in normal rhesus monkeys at term pregnancy. Following a pulse intravenous administration of 3H-cyclic AMP into the mother, a small fraction of the dose appeared in less than 1 minute in fetal blood. It appeared in the amniotic fluid after 5 minutes and reached maximum level in 20 minutes. The accumulation of 3H-cyclic AMP in the amniotic fluid in 1 hour was 0.03 per cent of the injected dose. The amount and time course of 3H-cyclic AMP accumulation in the fluid were not altered by tying the umbilical vessels. The transfer of 3H-cyclic AMP injected in utero into the fetal femoral artery resembled that in the mother; in 1 hour the amniotic fluid contained 0.22 per cent of the injected dose. When injected directly into the amniotic sac, more than 65 per cent of the injected dose remained unchanged after 1 hour, with minimal transfer into the maternal and fetal compartments. This study showed rapid bidirectional exchange of cyclic AMP between the mother and the fetus. Both of these compartments can contribute cyclic AMP to the amniotic fluid, independently or in concert. It remained fairly stable in the fluid and was not readily metabolized or transported out.

Amnion↗
PubMed1975

Maternal and neonatal effects of 1% and 2% mepivacaine for lumbar extradural analgesia.

Continuous lumbar extradural analgesia with mepivacaine was administered to two groups of patients in normal labour. One group (26 patients: 1% mepivacaine) received a mean total dose of 342 mg (4.93 mg/kg) per patient, and developed a mean blood concentration of mepivacaine at delivery of 1.82 mug/ml. The neonatal umbilical vein concentration was 0.84 mug/ml. The other group (30 patients: 2% mepivacaine) received a mean total dose of 776 mg (11.65 mg/kg) per patient, and developed a mean blood concentration of mepivacaine at delivery of 3.47 mug/ml. The neonatal umbilical vein concentration was 2.61 mug/ml. Four of the infants of mothers who received 1% mepivacaine were depressed (1-min Apgar score 6 or less), and six of the other group were depressed also. Usually, depression appeared to be related to obstetric factors, rather than to analgesia. Eleven of the 56 infants had umbilical vein mepivacaine concentrations of 3 mug/ml or greater; of these, three were depressed. This does not agree with the concept that the toxic threshold for mepivacaine is 3 mug/ml. In both groups a significant linear correlation was obtained between umbilical vein concentration and total dose of mepivacaine. A maximal dose of 12 mg/kg maternal weight in the non-obese or 12 mg/kg lean body mass in the obese is suggested for continuous extradural analgesia with mepivacaine, although healthy mothers and infants may tolerate much more.

Anesthesia, Epidural↗
PubMed1974

Detection of gas leaks in an anaerobic glove box.

An inert gas, Freon, can be added to the atmosphere of an anaerobic glove box without deleterious effect to cultures of anaerobic microorganisms. The sensitive probe of a Halogen Leak Detector passing over the outside surface of the box will pinpoint any escaping Freon and therefore locate the leak.

Anaerobiosis↗