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Biomedical subjects

L Turner

Publications and source records attributed to L Turner.

At least 127 records · Page 7Linked to original sources
PubMed1992

Ketorolac versus meperidine and hydroxyzine in the treatment of acute migraine headache: a randomized, prospective, double-blind trial.

STUDY OBJECTIVE: To compare the effectiveness of IM ketorolac with that of meperidine and hydroxyzine in the treatment of acute migraine headache. DESIGN: Prospective, randomized, double-blind trial. SETTING: Urban emergency department with an annual census of 42,000 patients. PARTICIPANTS: Forty-seven adult patients with migraines enrolled on 50 visits. INTERVENTIONS: Patients were randomly assigned to receive a single injection of either 60 mg ketorolac (group 1) or 100 mg meperidine and 50 mg hydroxyzine (group 2). Pain assessment was made using both visual-analog and verbal descriptor scales. RESULTS: At 60 minutes, 15 patients (60%) from group 1 (25) and 14 patients (56%) from group 2 (25) reported a great deal of complete relief (P = .77) Sixty-minute mean pain relief scores (3.35 versus 3.37) were different (P = .76). Nine patients (36%) from group 1 and seven patients (28%) from group 2 required additional analgesia (P = .76). CONCLUSION: Ketorolac is as effective as meperidine and hydroxyzine for the treatment of acute migraine headache.

Acute Disease↗
PubMed1992

Linkage maps in pea.

We have analyzed segregation patterns of markers among the late generation progeny of several crosses of pea. From the patterns of association of these markers we have deduced linkage orders. Salient features of these linkages are discussed, as is the relationship between the data presented here and previously published genetic and cytogenetic data.

Chromosome Mapping↗
PubMed1992

Pathways controlling the superoxide response during phagocyte differentiation: involvement of arachidonic acid and Ca2+ in the response to bacterial endotoxin.

In contrast to the phorbol ester oxidative response, which only develops during dimethylsulphoxide (DMSO)-induced differentiation of the human leukemic myeloblast HL-60 cell-line, the endotoxin response was observed in undifferentiated and differentiated cells. The Ca2+ response to endotoxin, detected in both differentiated and undifferentiated HL-60 cells, consisted of a transient 10-50 nM increase in intracellular Ca2+. A very slow, irreversible increase in intracellular Ca2+ was detected at high 1-100 micrograms/ml endotoxin concentrations, and this effect, and the inositol phosphate response, correlated with the surfactant activities of various endotoxins and Lipid A. Arachidonic acid and sodium arachidonate 1-50 microM stimulated a large 200-500 nM and transient Ca2+ response in undifferentiated HL-60 cells, which was significantly greater than that elicited by 1-50 microM eicosapentaenoic acid, and was not observed at similar concentrations of arachidonic acid methyl ester or myristic acid. These concentrations (1-50 microM) of arachidonic acid were observed to have surfactant activities on the plasma membrane. At lower arachidonic acid concentrations a marked potentiation of both Ca2+ and oxidative responses to the chemotactic peptide fMet-Leu-Phe was detected. It is possible that the arachidonic acid released during phospholipase A2 activation of neutrophils may be involved in cellular cross-talk and, at higher concentrations, in directly activating Ca2+ and superoxide production. It is also possible that previously reported effects of endotoxin at high concentrations are an in vitro artefact of surfactant properties of endotoxin.

Arachidonic Acid↗
PubMed1992

A comparison of risk factors in juvenile-onset and adult-onset recurrent respiratory papillomatosis.

The clinical triad of a firstborn delivered vaginally to a young (teenage) mother has been previously noted among juvenile onset recurrent respiratory papillomatosis (JO-RRP) patients. This study was based on a questionnaire survey of JO-RRP patients, adult onset recurrent respiratory papillomatosis (AO-RRP) patients, and juvenile and adult controls. The survey results revealed that the complete or partial triad was observed in 72% of JO-RRP patients, 36% of AO-RRP patients, 29% of juvenile controls, and 38% of adult controls. As compared with juvenile controls, JO-RRP patients were more often firstborn (P less than .05), delivered vaginally (P less than .05), and born to a teenage mother (P less than .01). Among adult participants, AO-RRP patients reported more lifetime sex partners (P less than .01) and a higher frequency of oral sex (P less than .05) than reported by adult controls. AO-RRP and JO-RRP appear to have distinguishable epidemiologic features indicating that the mode of human papillomavirus (HPV) transmission is different in these two disorders.

Adolescent↗
PubMed1991

Selection of motile nonchemotactic mutants of Escherichia coli by field-flow fractionation.

We have developed a chromatographic method for isolating bacterial cells that are motile but nonchemotactic. Separation of strains of different phenotype occurs along a thin horizontal channel between two stirred chambers, the lower one containing a chemical attractant. The channel is bounded above and below by rigid filters, permeable to the attractant but not to the bacteria. The lower part of the channel is occupied by a porous plate comprising a vertical array of capillary tubes. An aliquot of cells is injected at one end of the channel and eluted by continuous flow of cell-free medium. Fluid leaving the other end of the channel is collected in a fraction collector. Cells that respond to the gradient swim to the bottom of the channel where they are retarded by the capillary array. Nonmotile cells sink to the bottom and are trapped in a similar manner. Motile cells that fail to respond to the gradient diffuse across the full height of the channel and, thus, travel through the apparatus at the average velocity of the eluent. When mixed with wild-type cells at a ratio of 1:1000 and subjected to an aspartate gradient, aspartate-blind cells were recovered quantitatively. The enrichment was approximately 200 to 1. The wild-type cells that survived the selection had a poorly motile phenotype.

Cell Separation↗
PubMed1991

Is perinatal care in southwestern Ontario regionalized?

OBJECTIVE: To determine whether perinatal care in southwestern Ontario is regionalized, to identify trends over time in referral patterns, to quantify trends in perinatal death rates and to identify trends in perinatal death rates that give evidence of regionalization. DESIGN: Cohort study. SETTING: Thirty-two hospitals in southwestern Ontario (1 level III, 1 modified level III and 30 level II or I). PATIENTS: All pregnant women admitted to the hospitals and their infants. MAIN OUTCOME MEASURES: Antenatal and neonatal transfer status, live-born with discharge home alive from hospital of birth, stillborn, and live-born with death before discharge. RESULTS: Between 1982 and 1985 the antenatal transfer rate increased from 2.2% to 2.8% (p less than 0.003). The proportion of births of infants weighing 500 to 1499 g increased from 49% to 69% at the level III hospital. The neonatal transfer rate increased from 26.2% to 47.9% (p less than 0.05) for infants in this birth-weight category and decreased from 10.2% to 7.1% (p less than 0.03) for infants weighing 1500 to 2499 g. The death rate among infants of low birth weight was lowest among those born at the level III centre and decreased at all centres between 1982 and 1985. CONCLUSIONS: Perinatal care in southwestern Ontario is regionalized and not centralized; regionalization in southwestern Ontario increased between 1982 and 1985.

Female↗
PubMed1990

A copia-like element in Pisum demonstrates the uses of dispersed repeated sequences in genetic analysis.

A DNA sequence between two legumin genes in Pisum is a member of the copia-like class of retrotransposons and represents one member of a polymorphic and heterogeneous dispersed repeated sequence family in Pisum. This sequence can be exploited in genetic studies either by RFLP analysis where several markers can be scored together, or the segregation of individual elements can be followed after PCR amplification of specific members.

Base Sequence↗
PubMed1990

Chemotaxis of bacteria in glass capillary arrays. Escherichia coli, motility, microchannel plate, and light scattering.

Random and directed motility of bacterial populations were assayed by monitoring the flux of bacteria through a microchannel plate (a porous glass plate comprising a fused array of capillary tubes) separating two identical stirred chambers. Cells, washed free of growth medium by a new filtration method, were added to one chamber at a low density. Their number in the other chamber was determined from the amount of light scattered from a beam of a laser diode and recorded on a strip chart. Diffusion coefficients were computed from fluxes observed in the absence of chemical gradients, and chemotaxis drift velocities were computed from fluxes observed in their presence. Cells migrated through tubes of diam 10 microns more rapidly than through tubes of diam 50 microns, suggesting that the straight segments of their tracks were aligned with the axes of the smaller tubes. Mutants that are motile but nonchemotactic could be selected because they move through the microchannel plate in the face of an adverse gradient. Weak chemotactic responses were assessed from ratios of fluxes observed in paired experiments in which the sign of the gradient of attractant was reversed. Studies were made of wild-type Escherichia coli and mutants that are nonmotile, tumblely, smooth-swimming, aspartate-blind, or defective in methylation and demethylation. Chemotaxis drift velocities for the latter mutants (cheRcheB) were quite small.

Biophysical Phenomena↗
PubMed1989

Trace anesthetic gases during xenon arc photocoagulation for retinoblastoma.

In pediatric ocular examinations, administration of continuous-flow anesthetic gases containing nitrous oxide, halothane, and oxygen enables the physician to do safe, controlled, reproducible examinations. We did a study in which the levels of waste anesthetic gases were measured during xenon arc photocoagulation procedures used for retinoblastoma. Waste nitrous oxide and halothane gases measured during these procedures significantly exceeded the levels recommended by the National Institute of Safety and Health. These high levels are of particular importance because of the physician's proximity to the patient during the procedure. The high levels of waste gases may have immediate deleterious effects on the physician's functioning capacity and may also pose long-term health hazards for the physician and operating room personnel.

Air Pollutants, Occupational↗
PubMed1988

The effect of gabaculine on tetrapyrrole biosynthesis and heterotrophic growth in Cyanidium caldarium.

Pigment synthesis in four strains of the unicellular red alga Cyanidium caldarium with different pigment-synthesizing patterns was inhibited in the presence of gabaculine (3-amino-2,3-dihydrobenzoic acid). Parallel inhibition of light-induced chlorophyll and phycocyanin synthesis was observed in strain III-D-2, which only synthesizes pigments in the light. Similar parallel inhibition was observed in the dark in mutant CPD, which is able to synthesize chlorophyll and phycocyanin in the absence of light. Inhibition of pigment synthesis in all strains was overcome by addition of 5-aminolaevulinic acid. Inhibition of phycocyanin synthesis in mutant GGB (unable to synthesize chlorophyll) and inhibition of chlorophyll synthesis in mutant III-C (unable to synthesize phycocyanin) were also observed. Gabaculine also inhibited the heterotrophic growth of C. caldarium in the dark. However, inhibition was overcome after an extended lag period, following which cell growth proceeded at a similar rate to that of control cells not exposed to gabaculine. Heterotrophic growth in cells pre-exposed to gabaculine was not inhibited by subsequent exposure. Possible mechanisms for this adaptation are discussed.

Aminolevulinic Acid↗
PubMed1988

Diagnosis of Meleney's synergistic gangrene.

A retrospective and comparative study of 127 case reports of Meleney's postoperative progressive synergistic gangrene and of 62 examples of postoperative amoebic skin gangrene, showed that these two entities were clinically indistinguishable and that therefore a purely clinical diagnosis of Meleney's gangrene could not be made. Furthermore, a critical appraisal of the bacteriological data indicated that a certain diagnosis of Meleney's gangrene cannot be provided by the clinical bacteriologist. Finally, the histological features were entirely non-specific thus precluding a definitive diagnosis by the histopathologist. If Meleney's entity cannot be diagnosed its existence becomes debatable. The alternative diagnosis of cutaneous amoebiasis is advanced for consideration. Several of the outstanding features of Meleney's progressive gangrene, hitherto unexplained, are better understood if Entamoeba histolytica is accepted as the prime cause rather than bacteria.

Entamoebiasis↗