Biomedical subjects
Publications and source records attributed to N Johnson.
X-ray pelvimetry was performed on 43 women in the squatting and erect positions within 1 week of delivery. The act of squatting increased the transverse and antero-posterior pelvic dimensions by 1%. The theoretical mechanisms by which posture may affect dimensions are discussed.
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In a prospective double-blind randomized placebo-controlled clinical trial the efficacy of paracervical lignocaine was compared with saline in reducing pain in 70 women undergoing laser ablation of the cervical transformation zone. Paracervical lignocaine had no significant measurable effect on reducing the pain experience during the laser procedure. The mean subjective visual linear analogue pain score in the lignocaine and saline groups was 27% (95% CI 17 to 38) and 30% (95% CI 24 to 41) respectively (t = 1.0; P = 0.35). The median (quartiles) objective pain scores for the same groups were 0 (0-2) and 0 (0-1) respectively (P = 0.58).
Polymyxin B, a relatively toxic antibiotic, has potent endotoxin-neutralizing properties that may be beneficial as adjunctive therapy in gram-negative sepsis. Polymyxin B nonapeptide (deacylated polymyxin B) is devoid of antibiotic activity but retains the capacity to disorganize the outer membrane of gram-negative bacteria. To evaluate the potential therapeutic usefulness of this derivative, we produced purified polymyxin B nonapeptide, tested its in vivo toxicity in animals, and evaluated its in vitro antiendotoxin activity. Effectiveness as an antiendotoxin agent was assessed by examining the ability of polymyxin B nonapeptide to block the enhanced release of toxic oxygen radicals induced by lipopolysaccharide in human neutrophils (priming). In vivo, at doses of 1.5 and 3.0 mg/kg, polymyxin B nonapeptide did not exhibit the neuromuscular blocking, neurotoxic, or nephrotoxic effects that were observed with polymyxin B sulfate. Both polymyxin B and polymyxin B nonapeptide inhibited lipopolysaccharide-induced neutrophil priming in a concentration-dependent manner, but the parent compound, polymyxin B, was 63 times more effective on a weight basis. The inhibitory activity of both compounds, however, diminished rapidly when they were added after the start of the lipopolysaccharide-neutrophil incubation. We conclude that polymyxin B nonapeptide is less toxic than polymyxin B and, at the doses tested, lacks the neurotoxicity and nephrotoxicity of the parent compound. Polymyxin B nonapeptide retains the antiendotoxin activity of polymyxin B but is much less potent. The findings suggest that these compounds block an early step in the neutrophil priming process, possibly lipopolysaccharide attachment to or insertion into the neutrophil membrane.
A strong body of opinion contends that late terminations of pregnancy are better carried out by surgical methods. We show that the suggested advantages of greater safety and patient acceptance are based on out-of-date or inaccurate (biased) data. The advantages of medical methods are, however, equally unproven. However, we argue that the adverse emotional and symbolic effects of late surgical termination have moral force. We therefore contend that in the absence of strong patient preference, medical termination is the preferable method; and will remain of that opinion unless clear demonstration of the greater safety of surgical methods can be made at some future date.
The objectives of this study were to assess the quality of written responses provided by the Drug Information (DI) Service at The Hospital for Sick Children (HSC). A preliminary survey was circulated to 89 Canadian hospitals in December 1986 to guide us in developing this quality assurance audit. Of the 27 hospitals responding to this survey, 19 had formal DI centres. It was decided to perform our audit by means of a user satisfaction survey and a committee review of written DI responses. Fifty-six DI user surveys were distributed; 25 completed surveys were returned. Completeness of response was rated the highest (9.5 out of 10) by the respondents while the impact of the information provided on patient therapy was rated the lowest (8.3 out of 10). Sixty-three DI responses were to be reviewed by a committee which consisted of the Director, Division of Clinical Pharmacology, the Chief Medical Resident, and two pharmacists. Criteria to be examined included literature correlation/condensation, data documentation, literature evaluation, conclusions, references, organization, terminology and sentence structure. These criteria were all rated at greater than 90 percent compliance by the chief medical residents and pharmacists. Both the user survey and committee review led to the conclusion that our DI Service exhibits a high level of quality in its written responses to DI requests.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
To determine the accuracy of various predictors of school problems, we conducted a 3-year prospective study of 1999 children who began school in the Niagara region of Ontario in 1980. During the year before school entry the parents gave a health, developmental and behavioural history during an interview with a community health nurse, and the children underwent vision and hearing screening tests and the Denver Developmental Screening Test (DDST). At the end of the 1980-81 school year the kindergarten teachers rated the children's learning problems. At the end of the 1982-83 school year the presence of school problems was ascertained, and the predictive accuracy of items from the preschool history and examination and of the kindergarten teachers' ratings was calculated. The health, developmental and behavioural history with or without the DDST was found to predict later school problems with acceptable accuracy. The kindergarten teachers' ratings gave slightly more accurate predictions. We conclude that in communities where prompt diagnostic evaluation and effective therapeutic or preventive help can be provided to children identified as being at high risk, health professionals may play a useful role in screening for future school problems.
Many types of external trauma have been linked to the genesis of posttraumatic stress disorder (PTSD) and yet recent reports have focused almost exclusively on PTSD occurring in the Vietnam veteran (PTSD/veteran). The extent to which treatment experiences with PTSD/veteran can be generalized to other traumatized patients, for example, acute civilian populations, has not been investigated. Clinical observations comparing PTSD precipitated by a motor vehicle accident with PTSD/veteran suggested there were major differences between these two groups on the following variables: source of referral, age, sex, socioeconomic level, nature of stressor, timing of the stressor, character of the intrusive and avoidance symptoms, and treatment noncompliance behavior. These differences were of sufficient magnitude to call into question the feasibility, at this time, of constructing generalizations regarding PTSD utilizing only the PTSD/veteran population.
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Preliminary cervical dilatation using Lamicel, followed by relatively painless uterine probing was successful in removing 30 of 31 contraceptive devices that had not been removable in the outpatient clinic. This technique is simple, safe, inexpensive and well tolerated. It can be utilized to retrieve intrauterine contraceptive devices with missing tails when other conventional clinic procedures fail.
Investigation of the HLA system in 53 African eclamptic or imminently eclamptic women showed that they were significantly more likely to be heterozygous at the B locus than were normal controls. This did not apply to the A or D related loci.
We studied the cellular electrophysiologic effects of a lidocaine derivative, R-54718, that has been found effective in treating arrhythmias in experimental animals and in human subjects. R-54718 depresses Vmax, action potential amplitude, and conduction and accelerates repolarization of the canine Purkinje fiber action potential, with an effective concentration range 2 or 3 orders of magnitude lower than that of most class I antiarrhythmic drugs. Its action on Vmax shows no use dependence. In blood superfusion experiments its depressant effects on conduction are more profound than those of other class I compounds and significant toxicity can be seen. R-54718 also depresses delayed afterdepolarizations, as well as the abnormal automaticity occurring at low membrane potentials. However, automaticity occurring in fully polarized Purkinje fibers is not affected. In conclusion, R 54718 is unusual in its lack of use dependent action, in its differential action on normal and abnormal automaticity, and in its potency.
This article presents research involving the comparison of levels of occupational stress across multiple units of a large teaching hospital. Using a scale designed to measure a four-component model of occupational stress in medical environments, the results indicated that a significant amount of the variation in this measure was accounted for by the unit on which the respondent worked. There were no significant differences across levels of employment (e.g., housestaff, nurse clinician, registered nurse, licensed practical nurse, clerk).