Biomedical subjects
D L Bruce
Publications and source records attributed to D L Bruce.
Diphenhydramine reversal of vancomycin-induced hypotension.
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The partitioning of Staphylococcus epidermidis in aqueous two-phase systems.
The surface properties of two isolates of Staphylococcus epidermis were compared by cell partitioning in aqueous two-phase systems. Strain K805 was isolated from the cerebrospinal fluid of a child with a shunt infection and strain 1105 was obtained from human faeces and not known to have caused infection. Strain K805 was significantly more negatively charged than strain 1105 but there was no significant difference in hydrophobicity when cultures were grown for 18 h. However, prolonged incubation of strain K805 caused the production of extracellular slime and a marked increase in surface hydrophobicity. Both strains showed enhanced growth in biphasic cultures.
Postcholecystectomy pain relief by intrapleural bupivacaine in patients with cystic fibrosis.
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Blood gas values change slowly in apneic organ donors.
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Selective medium for the isolation and enumeration of Klebsiella spp.
A highly selective medium for the enumeration and isolation of Klebsiella pneumoniae and Klebsiella oxytoca was developed in which the typical colonies were convex and 1 to 2 mm in diameter. Their pigment was either a mucoid pink-red color or a more watery pale red with a dark red center. Relatively little colonial growth occurred for any other bacterial genera, and where such colonies did grow, they could be easily differentiated since the form was atypical. The medium already appears to have potential value as a means of assessing the efficiency of treating sewage and monitoring the microbiological quality of vegetables.
Fentanyl does not inhibit fertilization or early development of sea urchin eggs.
Sea urchin (Lytechinus variegatus) eggs have been used to study the effects of fentanyl on in vitro fertilization and early development as a model of human in vitro fertilization. Fentanyl did not affect fertilization or subsequent cell division when present in concentrations calculated to approximate or exceed those to which human ora would be exposed during clinical anesthesia. Lytechinus eggs exposed to fentanyl, then washed in fentanyl-free sea water before fertilization were also not affected and divided normally. The results suggest potential clinical utility of fentanyl during the harvesting of human ova for subsequent in vitro fertilization.
Preoperative clonidine withdrawal syndrome.
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Incompatibility group P-1 bla+ plasmids do not increase penicillin resistance of Pseudomonas acidovorans.
Incompatibility group P-1 plasmids with the bla+ genotype were transferred from various Escherichia coli strains to Pseudomonas acidovorans strain 29. When resistance to ampicillin was used as the criterion, none of these plasmids appeared able to express their Bla+ phenotype in this host. When the plasmids were subsequently transferred back from these ampicillin-sensitive P. acdiovorans transcipients to E. coli strains, it was found that the Bla+ phenotype was again expressed. Although beta-lactamase was not detected in cultures of P. acidovorans transcipients, macroiodometric determinations of beta-lactamase activity made on broken cell suspensions revealed that beta-lactamase was indeed synthesized. It was concluded that P. acidovorans strain 29 allows expression of the bla gene within the cell but that this organism is unable to excrete the enzyme.
Elevation of creatine phosphokinase in young men after recreational exercise.
Twenty healthy male volunteers were divided into four groups for a period of recreational physical exercise. Standard blood chemistry determinations were made before exercise and on the two subsequent days. Creatine phosphokinase (CPK), SGOT, and lactic dehydrogenase levels were transiently elevated, but the change was considered significant only in the CPK level after certain types of exercise. Persons having these determinations performed should be questioned about recent physical exertion in the event of abnormal laboratory results.
Studies on immunoglobulins of Richardson's ground squirrel--I. Characterization of ground squirrel IgG.
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Effects of trace anaesthetic gases on behavioural performance of volunteers.
Nitrous oxide and halothane, in concentrations as low as 50 p.p.m. and 1.0 p.p.m. respectively, caused measurable decrements in performance in psychological tests in healthy male volunteers. Nitrous oxide alone caused similar effects. The functions apparently most sensitive to these low concentrations of anaesthetic agents were visual perception, immediate memory, and a combination of perception, cognition and motor responses required in a task of divided attention to simultaneous visual and auditory stimuli. These effects were absent in subjects exposed to nitrous oxide 25 p.p.m. and halothane 0.5 p.p.m.
Halothane action on lymphocytes does not involve cyclic AMP.
Both theophylline and halothane inhibited transformation of human lymphocytes by phytohemagglutinin (PHA). Theophylline did not augment the inhibitory action of halothane and depressed PHA transformation of halothane-treated cells to the same extent as that of air-treated cells. Halothane- and air-treated lymphocytes, prior to PHA addition, had the same content of cyclic AMP. The addition of PHA to these cultures raised cyclic-AMP concentrations to the same extent in halothane- and air-treated lymphocytes. Halothane action on PHA-stimulated lymphocytes appears not to involve changes in cyclic nucleotide metabolism.
Failure of nitrous oxide to inhibit transformation of lymphocytes by phytohemagglutinin.
Nitrous oxide, in an incubator concentration of 70%, failed to inhibit nuclear enlargement of lymphocytes stimulated to transform by phytohemagglutinin (PHA).
An audiovisual test of divided attention.
A description is given of an audiovisual reaction time task, performance of which was maximal after 15 min. practice and which lasted at this level for 1 wk. Sensitivity of the test was shown in an adverse effect of inhalation of traces of anesthetic gases. Comparing responses to auditory and visual stimuli, the control auditory reaction times were faster but were lengthened more in the presence of anesthetics than were the visual ones. This test may be useful in other studies of subtle depressant drug effects.
Halothane inhibition of rna and protein synthesis of PHA-treated human lymphocytes.
Cultured human lymphocytes treated with phytohemagglutinin (PAH) ahd higher rates of RNA and protein synthesis, as judged by incorporation of the labelled precursors -3H-URIDINE AND -14C-leucine, than did control cultures without PHA. These cultures were prepared from cells of the same donor, as were a third set of cultures which were equilibrated with 2 per cent halothane. The increased rates of RNA and protein synthesis six and 16 hours after PHA ADDITION WERE INHIBITED BY THE HALOTHANE, MODESTLY AT SIX HOURS AND STRIKINGLY AT 16 HOURS. These experiments provide further evidence that halothane prevents recruitment of resting cells into the active cycle of cell division.
Psychological studies of human performance as affected by traces of enflurane and nitrous oxide.
Thirty human subjects were exposed for four hours to 500 ppm N-2O and 15 ppm enflurane in air and then, within five minutes, given a 35-minute battery of psychological tests. Performance of a divided-attention audiovisual task and a digit-span memory test were significantly decreased compared with control data following exposure to air. A tachistoscopic task, four tests from the Wechsler memory scale, and five others from the Wechsler Adult Intelligence Scale were unaffected. Thirty subjects exposed to 500 ppm N-2-O in air only scored significantly lower on the digit-span test only.
The anesthetic effect of air at atmospheric pressure.
Nitrogen has recognized narcotic potential at hyperbaric pressures. No narcotic effect of helium has been demonstrated at any pressure. We evaluated the effect of nitrogen in air at one atmosphere on human performance by comparing it with helium-oxygen using a four-alternative divided-attention task that requires rapid response to auditory and visual signal changes. There was a 9.3 per cent decrease in response time when subjects breathed helium-oxygen, a signigicant change (P less than 0.001). This change could not be ascribed to practice since the order of presentation of gases did not have a significant effect. It concluded that the nitrogen in ambient air slightly but measurable impairs human performance compared with a non-anesthetic gas such as helium.