Safety behaviours among Alaskan Native and American Indian people living in Alaska.

OBJECTIVE: To examine self-reported safety behaviours among 3828 Alaskan Native and American Indian people enrolled in the Alaska Education and Research Towards Health (EARTH) Study, 2004-2006. DESIGN: A cross-sectional analysis of baseline data from a cohort study. A non-random sample of participants (2322 women and 1506 men) aged > or =18 years from three regions of Alaska completed questions on safety behaviours as part of a comprehensive health and lifestyle computer-assisted self-administered questionnaire. RESULTS: Most participants reported never driving after drinking (94.1%) or riding with a driver who had been drinking (91.3%). Fewer (74.1%) participants reported using a seatbelt always or almost always when riding in a vehicle. Only about half (55%) always kept to the speed limit when driving or used a personal flotation device when boating (51.5%). Even fewer (20.5%) reported using a helmet when riding on off-road vehicles, including four-wheelers and snowmobiles. Factors identified among those least likely to use safety devices and practise good safety behaviours are: younger age, lower household income and education, non-married, speaking only English at home, and a self-reported health status of poor to fair (p<0.05). CONCLUSIONS: Recommendations for future injury prevention efforts in this population are to increase use of personal flotation devices while boating and address the underuse of helmets with off-road vehicles. Limited prevention resources should be used to target those who engage in risky behaviours to maximise programme impact.

A case study of misrepresentation of the scientific literature: recent reviews of chiropractic.

Accurate use of published data and references is a cornerstone of the peer-review process. Statements, inferences, and conclusions based upon these references should logically ensue from the data they contain. When journal articles and textbook chapters summarizing the safety and efficacy of particular therapies or interventions use references inaccurately or with apparent intent to mislead, the integrity of scientific reporting is fundamentally compromised. Ernst et al.'s publication on chiropractic include repeated misuse of references, misleading statements, highly selective use of certain published papers, failure to refer to relevant literature, inaccurate reporting of the contents of published work, and errors in citation. Meticulous analysis of some influential negative reviews has been carried out to determine the objectivity of the data reported. The misrepresentation that became evident deserves full debate and raises serious questions about the integrity of the peer-review process and the nature of academic misconduct.

Low-energy DC catheter ablation of left atrial ectopic tachycardia that had resulted in reversible cardiomyopathy.

Catheter ablation of automatic atrial tachycardia has been previously reported in a small number of adult cases in which the ectopic focus was predominantly located in the right atrium. We report on a patient with atrial automatic tachycardia originating in the left atrium, in whom successful low-energy DC catheter ablation was performed via a transseptal puncture. The patient presented with severe congestive cardiac failure that resolved following the procedure. Catheter ablation in such cases is feasible, it can reverse tachycardia induced ventricular function impairment, and should be attempted before resorting to open heart surgical ablation.

Major complications of coronary arteriography: the place of cardiac surgery.

The records of the catheter laboratory at St George's Hospital between 1983-1988 were reviewed to determine how often emergency coronary bypass surgery was performed because of a complication arising during elective coronary arteriography. A total of 11,216 cardiac procedures were performed; 5781 were confined to left ventricular angiography and coronary arteriography in patients with suspected coronary artery disease. Fourteen patients, whose investigation had been considered routine, suffered profound circulatory collapse during the procedure. Emergency cardiac surgery was undertaken in 13, with long term survival in 10. This experience suggests that, even in patients considered to be at low risk, there were major complications requiring emergency coronary surgery in at least 2.4 per 1000 coronary arteriograms performed. Survival after emergency cardiac surgery in these patients was 77%. These findings and the access to cardiac surgery should be considered when the development of facilities for cardiac catheterisation is planned.

Control of Campylobacter fetus in artificially contaminated bovine semen by incubation with antibiotics before freezing.

Fresh, diluted semen containing 1.55 X 10(6) cfu/ml of Campylobacter fetus subsp. venerealis was incubated with 500 iu of penicillin, 500 micrograms of streptomycin, 160 micrograms of lincomycin and 300 micrograms of spectinomycin per ml at 35 degrees C for 0, 1, 2, 5, 10, 20 or 40 minutes. The semen was cooled to 5 degrees C, packaged in 0.25 ml French straws and then frozen in liquid nitrogen for 2 weeks. Immediately after thawing and removal of the antibiotics by centrifugation semen samples from each of the seven treatment groups were cultured as for C. fetus. Semen samples were also examined by in-vitro tests for sperm motility prior to and post-freezing. Incubation with the antibiotics for 5, 10, 20 or 40 min prior to freezing reduced the numbers of C. fetus in the semen to non-detectable levels in 38%, 69%, 88% and 100% of samples respectively. The incubated semen showed no significant reduction of sperm motility although fertility trials have not been done.

Multiple bilateral coronary arterial to pulmonary artery fistulae in an asymptomatic patient.

We describe an asymptomatic patient with multiple fistulae between coronary arteries and the main pulmonary artery with an insignificant left-to-right shunt. Possible embryological basis of this anomaly is discussed.

Relation of human cardiac action potential duration to the interval between beats: implications for the validity of rate corrected QT interval (QTc).

Fourteen patients undergoing routine cardiac catheterisation were paced at a steady frequency; after this test, stimuli were introduced with a variable preceding interval (test pulse interval). The QT interval of the electrocardiogram and the duration of the monophasic action potential of the right ventricle were measured. QT interval is a function of action potential duration; the two variables were very closely correlated in this study. Both these variables increased in duration with increasing test pulse interval. A biphasic response, as previously reported, was not seen. An increase in steady state pacing frequency caused QT interval and action potential duration to decrease for any given R-R interval. When frequency of stimulation was suddenly increased and then maintained, there was an immediate action potential shortening followed by a further more gradual shortening occurring over several minutes. These results imply that a simple correction of QT interval for heart rate (QTc) is inadequate. It is concluded that the relation between action potential duration (or QT interval) and heart rate depends on both the instantaneous interval between beats and the duration of the prevailing heart rate.

Relationships between beat-to-beat interval and the strength of contraction in the healthy and diseased human heart.

Twenty-six adult patients, classified by clinical and catheter criteria into groups of those with normal and abnormal left ventricular function, were studied during cardiac catheterization. Right heart pacing was established, and left ventricular dP/dt was measured with end-catheter manometers. By varying the interval preceding a test beat after periods of steady pacing it was confirmed that recovery of left ventricular mechanical function (maximum dP/dt) occurs approximately 800 msec (optimum interval) after a beat. The augmentation of maximum dP/dt of the first 2 beats after an extrasystole, each spaced at the optimum interval, was also studied; the amount of potentiation was varied by alterations in extrasystolic interval. Potentiation decayed from the first to the second postextrasystolic beat with a ratio that was fixed in each individual patient. The ratio (recirculation fraction) was higher in patients with normal than in those with abnormal left ventricular function (mean +/- SD 0.52 +/- 0.10 vs 0.37 +/- 0.11, p less than .005). There was an inverse relationship between this ratio and the degree of potentiation of the first postextrasystolic beat (r = .80, p less than .001). We postulate a disturbance of excitation-contraction coupling mechanisms to explain these effects.

Properties of an immunogenic fraction from Brucella abortus 45/20.

Hot saline extracts of Brucella abortus strain 45/20 contain up to 4 protein components. Some of these components are shared with other Brucella strains but one appears specific to B. abortus 45/20 or possibly other non-smooth Brucella strains. The extracts are antigenic in guinea-pigs and evoke protective immunity against virulent B. abortus. The rough antigen specific activity appears to be associated with a protein component rather than lipopolysaccharide.

Response of the badger (Meles meles) to infection with Brucella abortus.

Three badgers exposed to conjunctival instillation of Brucella abortus strain 544 developed a mild subclinical infection accompanied by the production of agglutinating and complement fixing antibodies. Six months after inoculation, the infection could not be detected in one badger and was confined to lymphoid tissue in the other two. No cell mediated immune response to B abortus antigens could be detected by in vitro lymphocyte transformation tests or intradermal tests for delayed hypersensitivity during the observation period.