A signal-detection theory based perspective on design of warning

The effects of warnings are analyzed using a distributed signal-detection theory model. It is established that selectivity always increases effectiveness. The implications to optimal warning design for intermittent versus continuous hazards are discussed. The changes in the behavior of the 6 human subjects in response to changes in the warning levels are consistent with the predictions of the model.     

Open-heart correction of tetralogy of Fallot in an acyanotic dog

Tetralogy of Fallot was diagnosed in an acyanotic 11-month-old dog. Predicted pressure gradient across the pulmonic valve, as assessed by use of continuous wave Doppler echocardiography, was 94.5 mm Hg. Bidirectional shunting was identified by means of selective angiography. Open-heart correction was performed, using a transatrial approach with limited ventriculotomy and cardiopulmonary bypass. The hypertrophied infundibulum was resected, the ventricular septal defect was closed primarily, and a transannular pericardial patch graft was applied. Pressure gradients across the pulmonic valve were 52.9 and 22.8 mm Hg 2 weeks and 4 months after surgery, respectively. Advances in cardiopulmonary bypass, anesthetic management, and use of the transatrial approach may improve the success of open-heart correction of tetralogy of Fallot in dogs.     

A study of the diagnostic accuracy and reliability of the Scoliometer and Adam's forward bend test

STUDY DESIGN: Study of the diagnostic accuracy and interexaminer reliability of scoliosis diagnostic tests. OBJECTIVES: To estimate the sensitivity, specificity, and predictive value of the Scoliometer (National Scoliosis Foundation, Watertown, MA) and Adam's forward bend test in diagnosing scoliosis, and to determine the interexaminer reliability of the Scoliometer and Adam's forward bend test. SUMMARY OF BACKGROUND DATA: Exposure to diagnostic radiation in patients with adolescent idiopathic scoliosis may result in a small but significant increase in cancer rates. The full-spine radiographic examination remains the standard procedure for the assessment of scoliosis. There is a need for a valid and reliable noinvasive test to assess scoliosis. METHODS: Two examiners independently assessed 105 patients presenting to a scoliosis clinic for trunk asymmetry with Adam's forward bend test and axial trunk rotation with the Scoliometer. The Cobb method served as the gold standard. RESULTS: The interexaminer agreement for the Scoliometer is excellent in the thoracic spine and substantial in the lumbar spine. The interexaminer measurement error shows poor precision for thoracic and lumbar Scoliometer measurements. The interexaminer agreement for Adam's forward bend test is substantial in the thoracic spine and poor in the lumbar spine. Adam's forward bend test is more sensitive than the Scoliometer in detecting thoracic curves measuring 20 degrees or more by the Cobb method. Receiver operating characteristic curve analysis suggests that the use of the Scoliometer marginally improves the ability of diagnosing a scoliosis in the thoracic spine. CONCLUSIONS: The Scoliometer and Adam's forward bend tests have adequate interexaminer reliability for the assessment of thoracic curves. The Scoliometer has better interexaminer agreement in the lumbar spine. However, the Scoliometer has a high level of interexaminer measurement error that limits its use as an outcome instrument. Because Adam's forward bend test is more sensitive than the Scoliometer, the authors believe that it remains the best noninvasive clinical test to evaluate scoliosis.     

Serum aspirin esterase activity in women with habitual aspirin intake

A method for the determination of aspirin esterase activity in serum is described. Sera from 59 pregnant women who were habitual aspirin users were found to have a mean enzyme activity value statistically lower than those of 68 non-pregnant women controls or of 12 pregnant women controls who were either occasional users of the drug or were non-users. The distribution of enzyme activity in the experimental group was also significantly different from that of the control group. It is postulated that the low enzyme activity may further aggravate the injurious effects of high intake of aspirin.     

Reduction of intrinsic sinoatrial frequency and norepinephrine response of the exercised rat

Physical training is associated with a reduction of intrinsic sinoatrial activity; the present study examined the role of the parasympathetic nervous system in this reduction. Six groups of rats were studied for 10 weeks: inactive control; treadmill exercised; parasympathetic receptor blockade with atropine; exercise plus atropine; parasympathetic receptor stimulation with carbachol; and exercise plus carbachol. In vivo ISF (cardiac frequency 20 min after injection of propranolol and atropine) was measured at 3-week intervals. At the end of 10 weeks the right atrium was excised, in vitro measurements were made of ISF, and chronotropic dose-response curves to acetylcholine and norepinephrine were established. In vivo, ISF was reduced with time, the greatest reduction being found in the exercise plus atropine group; the treadmill-exercised and the atropine-treated groups also had a greater reduction than the control group. In vitro, no differences were observed in acetylcholine responses. The maximum norepinephrine chronotropic response was reduced in the treadmill-exercised and the exercise plus atropine groups. The maximum norepinephrine-induced frequency correlated with the in vitro ISF (r = 0.75). Thus, ISF was reduced with training, but this effect was independent of parasympathetic activity. The properties of the sinoatrial node which set ISF also influenced the maximum norepinephrine response.     

The ocular manifestations of Beh?et's disease

Of 32 patients with Beh?et's disease, 21 had uveitis. The uveitis was seldom the initial manifestation of systemic disease, but once established, it tended to become chronic and bilateral, involving the anterior and posterior segments. Hypopyon was a relatively uncommon occurrence in this series. All patients with uveal inflammation had obvious cellular reactions within the vitreous body. Other posterior segment manifestations of the disease included localized retinal edema, macular edema, disc edema, retinal pigmentary changes, and accumulation of exudative material in the deep retina. One patient developed a necrotizing retinitis with deep retinal exudation and subsequent retinal detachment. Occlusions of retinal vessels were common. Neuro-ophthalmologic manifestations of Beh?et's disease included cranial nerve palsies, a homonymous hemianopic field defect, and papillitis.