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Biomedical subjects

J R Johnson

Publications and source records attributed to J R Johnson.

At least 181 records · Page 10Linked to original sources
PubMed1993

Anesthetic effects on motor evoked potentials in dogs.

The effects of the various anesthetic agents on the production of transcranial magnetic motor evoked potentials (tcMMEP) were studied in a canine model. Pre-anesthetic baseline tcMMEPs demonstrated consistency in onset latency measurements and variability in measurement of peak-to-peak amplitudes. Changes in tcMMEPs were evaluated following the individual administrations of sodium pentothal, etomidate, halothane, fentanyl, and ketamine. For induction of anesthesia, etomidate was compatible with tcMMEP production, whereas sodium pentothal resulted in loss of hindlimb potentials for a period of 45 minutes. For maintenance of anesthesia, halothane was incompatible with the measurement of tcMMEPs. Fentanyl administration was consistent with the recording of reliable tcMMEPs, with consistent onset latencies but widely variable peak-to-peak amplitudes. Ketamine was compatible with stable and reproducible tcMMEP production. The results of this study suggest that anesthetic agents have a predictable and consistent effect on tcMMEP responses.

Anesthetics↗
PubMed1993

Sexual aggression and love styles: an exploratory study.

The relationship between sexual aggression and theoretical love styles was studied. Based on self-reported sexual history, 63 college men were grouped as having either consensual sexual experience only (n = 33) or having verbally coercive sexual experience (n = 30). Analyses were conducted using six love style scales, likelihood to rape, likelihood to use sexual force, masculinity, and sociopathy to predict sexual coercive group membership. Logistic regression indicated that the Ludus love style, a manipulative, game-playing orientation towards intimate relationships, was the best predictor of sexual coercion among the six love styles. Additionally, logistic regression indicated that the Ludus love style was as effective in classifying men as coercive or noncoercive as other dispositions related to sexual aggression. These results suggest that the Ludus love style may serve as a unifying construct for dispositions related to sexual aggression. This study constitutes an initial attempt to link sexually coercive behaviors to a theoretical model of intimate relationships. Results are discussed in the context of a situational model of sexual coercion.

Adult↗
PubMed1993

Correlation of motor-evoked potentials, somatosensory-evoked potentials, and the wake-up test in a case of kyphoscoliosis.

The ability to monitor the descending motor pathways of the spinal cord during surgery is an important goal in neurophysiologic monitoring of spinal deformities. This report describes a case of a severe spinal deformity for which instrumentation and reduction carried a significant risk of neurologic complications. During the procedure, changes in neurologic status were monitored simultaneously using both SSEPs and tcMMEPs. The reliability of these two complimentary modalities was then verified by concurrent wake-up tests. This case provides documentation of the reliability of tcMMEP responses when an accurate assessment of motor function was necessary.

Adult↗
PubMed1993

Metabolism and dosimetry of tritium.

This document was prepared as a review of the current knowledge of tritium metabolism and dosimetry. The physical, chemical, and metabolic characteristics of various forms of tritium are presented as they pertain to performing dose assessments for occupational workers and for the general public. For occupational workers, the forms of tritium discussed include tritiated water, elemental tritium gas, skin absorption from elemental tritium gas-contaminated surfaces, organically bound tritium in pump oils, solvents and other organic compounds, metal tritides, and radioluminous paints. For the general public, age-dependent tritium metabolism is reviewed, as well as tritiated water, elemental tritium gas, organically bound tritium, organically bound tritium in food-stuffs, and tritiated methane.

Environmental Exposure↗
PubMed1993

Activity of a nitrofurazone matrix urinary catheter against catheter-associated uropathogens.

Nitrofurazone-coated urinary catheter segments inhibited 51 (75%) of 70 urinary bacterial isolates from patients with indwelling catheters. Inhibition zones correlated significantly with the nitrofurazone MIC (r2 = 0.79, P = 0.0001). All strains except the Pseudomonas spp. were inhibited by < or = 64 micrograms of nitrofurazone per ml. MICs of nitrofurazone and nitrofurantoin correlated significantly (r2 = 0.93, P = 0.0001).

Bacteria↗
PubMed1993

P1-antigen-containing avian egg whites as inhibitors of P adhesins among wild-type Escherichia coli strains from patients with urosepsis.

Among 58 Escherichia coli urosepsis isolates, P1-antigen-containing dove and pigeon egg whites were significantly more effective inhibitors of P-adhesin-specific agglutination than were chicken egg whites or globoside. Globoside's inefficacy may have resulted from a proadherence effect of globoside's lipid tail. Adhesin phenotypes determined with dove and pigeon egg whites as as agglutination inhibitors corresponded closely with phenotypes defined by comparative hemagglutination of human P1 and p erythrocytes. These data suggest that avian P1-antigen-containing substances may provide a useful alternative method for P adhesin inhibition among uropathogenic E. coli strains.

Adhesins, Escherichia coli↗
PubMed1993

High-resolution MRI in the investigation of recurrent pain after lumbar discectomy.

We used gadolinium-enhanced fat-suppressed MRI to investigate 67 patients with persistent pain after lumbar discectomy. Twenty-five patients had reoperations for lesions diagnosed in this way. Eleven were for recurrent disc prolapse at the same level and sciatica was relieved by all but one. Five operations were for prolapse at an adjacent level and all were successful. The diagnosis of sepsis was less precise, but extension of tissue enhancement into the operated disc space was found to be significant. Only three patients had evidence of arachnoiditis which suggests that this condition has been too often diagnosed as a cause of persisting low back pain.

Adolescent↗
PubMed1993

[Stabilization of 150 unstable spinal injuries with the Cotrel-Dubousset instrument--analysis of results].

The present study is a retrospective analysis of spinal fracture treatment with the Cotrel-Dubousset instrumentation technique. 150 unstable injuries of the spine were treated with the CD implant at the University of Louisville--Level I Trauma Center--between February 1985 and March 1989. There were 67 burst fractures, 48 compression fractures and 21 fracture dislocations, 8 flexion distraction fractures and 6 flexion rotation injuries. Ninety-three patients underwent anterior cord decompression and strut grafting followed by posterior CD instrumentation and posterolateral fusion. Fifty-seven patients had posterior CD instrumentation and fusion alone. No neurological deterioration after the procedure was observed, 33 patients improved neurologically. Hospital stay ranged between 7 and 60 days (mean 20 days). 114 patients had a minimum follow up of 6 months (range 6-52 months). The mean follow up was 17.7 months. At final follow up 77.8% of the patients had returned to work and 84.2% of the patients were almost painfree. The mean loss of correction in the sagittal plane was 6.2 degrees (range: 0 and 42 degrees) at final follow up. As technical complications there were four hook cut outs (2.6%) of which two underwent reosteosynthesis and two did not effect the clinical or radiographic result. The high stability of the device provides a decreased risk of neurological deterioration, a decreased risk of posttraumatic kyphosis and early rehabilitation.

Adolescent↗
PubMed1992

Success of DNA fingerprinting after failure of biotyping, antimicrobial susceptibility testing, and plasmid analysis to reveal clonality of multiple blood and urine isolates from a patient with Escherichia coli urosepsis.

Multiple isolates of Escherichia coli from the blood and urine of a 60-year-old woman with acute pyelonephritis exhibited different biotypes, antimicrobial susceptibility patterns, and plasmid profiles, suggesting the presence of polymicrobial bacteriuria and leaving in question the origin of the bacteremia. Only after bacterial restriction endonuclease analysis of total bacterial DNA was it discovered that all isolates represented the same strain, with plasmid instability possibly accounting for the varied antimicrobial susceptibility patterns observed. We conclude that the biotype, antimicrobial susceptibility profile, and plasmid profile are sometimes inadequate to clarify the relationships between different clinical isolates of E. coli from a single patient and can lead to erroneous epidemiologic conclusions. DNA fingerprinting can resolve dilemmas these less precise techniques leave unresolved.

Anti-Bacterial Agents↗
PubMed1992

Detailed histopathological examination contributes to the assessment of Escherichia coli urovirulence.

To determine the usefulness of detailed histopathological evaluation in the assessment of urovirulence of different Escherichia coli strains in a mouse model of ascending, unobstructed urinary tract infection, and to evaluate the relationship between susceptibility to urinary tract infection and renal levels of P fimbrial receptor glycolipids in different mouse strains, female Swiss Webster and Balb/c mice were inoculated transurethrally with one of four different well-characterized wild type E. coli strains or with an E. coli K-12 laboratory strain, and renal glycolipid levels were determined for both mouse strains. In Swiss Webster mice, each of the wild type E. coli strains was more virulent than the laboratory strain by both microbiological and histopathological criteria. Despite the common origin and identical virulence factor profiles of the three urosepsis isolates studied, one was significantly less urovirulent than the other two. Paradoxically, this strain stimulated a greater degree of leukocytosis than did the more urovirulent strains. Balb/c mice were significantly more susceptible to infection with this strain than were Swiss Webster mice, a difference possibly contributed to by the significantly higher renal levels of P fimbrial receptor glycolipids in Balb/c mice. Detailed histopathological analysis revealed significant differences in virulence between bacterial strains, and in susceptibility to infection between different mouse strains, that were inapparent from culture results alone.

Animals↗