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Mental stress increases cardiovascular morbidity and mortality. Although laboratory mental stress often causes less myocardial ischemia than exercise stress (ES), it is unclear whether mental stress is intrinsically different or differences are due to less hemodynamic stress with mental stress. We sought to evaluate the hemodynamic and ischemic response to intense realistic mental stress created by modern flight simulators and compare this response to that of exercise treadmill testing and conventional laboratory mental stress (CMS) testing in pilots with coronary disease. Sixteen airline pilots with angiographically documented coronary disease and documented myocardial ischemia during ES were studied using maximal treadmill ES, CMS, and aviation mental stress (AMS) testing. AMS testing was done in a sophisticated simulator using multiple system failures as stressors. Treadmill ES testing resulted in the highest heart rate, but AMS caused a higher blood pressure response than CMS. Maximal rate-pressure product was not significantly different between ES and AMS (25,646 vs 23,347, p = 0.08), although these were higher than CMS (16,336, p

Breastfeeding is a natural physiologic process upon which human survival has depended for uncounted generations. Natural selection over millions of years has ensured that breastmilk contains all the nutritional requirements of the newborn period and beyond. In order to prevent problems for the few, modern management of labour, delivery and the postpartum period has subjected most mothers and infants to routines which are contrary to the physiologic principles underlying successful breastfeeding. The early introduction of bottles may render suckling less effective or may result in breast refusal, thus paving the way for failure to thrive, hyperbilirubinemia, "colic" and crying, prolonged and frequent feedings, sore and cracked nipples for the mother, and it may contribute to the onset of plugged ducts and mastitis. Alternatives to bottles can be used when supplementation is thought to be indicated. They include using a lactation aid, finger feeding, or feeding with a cup, spoon, or eyedropper.

Recently, some of my patients were instructed not to breastfeed for 24 to 48 hours after magnetic resonance imaging scans. Is this based on scientific evidence?No. On the contrary, evidence indicates unequivocally that the contrast media used for both magnetic resonance imaging and computed tomography scans are excreted into breast milk in such small quantities that there is no concern at all for nursing babies.

Lyophilized plasma derivatives are more stable to heat than when they are in the liquid state. Commercial Factor VIII (antihemophilic factor) was seeded with a measured quantity of hepatitis B virus. The contaminated material was then lyophilized and subjected to heat of 60 degrees C for 30 hr. Chimpanzees were inoculated with the heat-treated antihemophilic factor or sham-treated antihemophilic factor that had been held at 4 degrees C. Surprisingly, hepatitis B virus survived the heating procedure with no apparent loss in titer: the incubation period to appearance of HBsAg was that expected for the challenge dose of virus. Even more surprising, one chimpanzee (the recipient of the unheated antihemophilic factor) also developed non-A, non-B hepatitis and two chimpanzees (recipients of the heated antihemophilic factor) also developed delta hepatitis. Neither of these agents was a contaminant of the hepatitis B virus challenge pool, since the purity of this hepatitis B virus pool was established previously in chimpanzees. Thus, both a non-A, non-B agent and the delta agent apparently contaminated the commercial antihemophilic factor. This is the first direct evidence for contamination of antihemophilic factor with the delta agent and confirms previous seroepidemiologic evidence for its presence in pooled plasma derivatives. Subsequent inactivation studies were performed with antihemophilic factor experimentally contaminated with the Hutchinson strain of non-A, non-B hepatitis virus. In these studies, heating at 60 degrees C for 30 hr in the dry state rendered antihemophilic factor free of detectable non-A, non-B hepatitis virus.

Summary Physical Capacities and Working Conditions are two of eight components used in recent United States Employment Service occupational research designed to develop a new occupational classification structure (2, 9). This research has been carried out with 4,000 jobs, an 18% sample of Dictionary of Occupational Titles. The ratings made for the two components described in this article as well as for Training Time, Aptitudes, Interests, and Temperaments have recently been published as an informational tool supplementing the D.O.T. (12). Although satisfactory consistency among ratings was obtained among a group of raters working from job descriptions, the question was, how good was this information when compared with similar ratings made for the same jobs by actual observation of the jobs in plants? Some indication of consistency with on-the-spot-observations was particularly necessary prior to publication. A previous study (10) had indicated satisfactory reliability of Aptitude ratings made similarly from direct and indirect observations. Would the same hold true for Physical Capacities and Working Conditions?

Infant walkers have been described as a cause of unexpected trauma in the first year of life. We conducted a prospective study to determine the mechanism and pattern of walker injuries presenting to an urban pediatric teaching hospital. We also studied the patterns of walker use. All injuries sustained by infants in baby walkers during a 1-year period were reviewed. The 139 injuries included 29 fractures. The most severe injuries were caused by falls down stairs; these falls accounted for 123 of the injuries. Stair gates were present in one third of all falls. At follow-up 2 months later, two thirds of the children had been in the walker subsequent to the injury. One third were still in the walker at 2 months after their initial injury. Less than half of the homes that had not had stair gates in place had acquired them at the time of follow-up. Baby walkers represent a cause of significant injury in the infant population; studies of warning labels and anticipatory guidance are needed.