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Biomedical subjects

W Daniels

Publications and source records attributed to W Daniels.

10 recordsLinked to original sources

The effectiveness of various cervical orthoses. An in vivo comparison of the mechanical stability provided by several widely used models.

STUDY DESIGN: The amount of motion allowed by various cervical orthoses was compared with the amount of unrestricted neck motion in vivo. OBJECTIVES: To determine how much mechanical stability commonly used cervical orthoses provide to the wearer. SUMMARY OF BACKGROUND DATA: Few studies have compared quantitatively the restriction of motion from cervical orthoses that are commonly prescribed for patients. No studies have used methods allowing measurement of all three rotations throughout the range of motion in passive and active tests. Previous studies may have overstated the amount of restriction provided resulting from the methods used. METHODS: Five subjects were tested for cervical range of motion in flexion-extension, axial, rotation, and lateral bending. Each was tested with no collar, with soft collar, with Philadelphia collar, with Philadelphia collar with thoracic extension, and with sterno-occipital mandibular immobilizer brace. Each test was conducted passively and actively. Measurements were taken with the CA-6000 Spine Motion Analyzer, a highly accurate and precise computerized linkage system that simultaneously records all three rotations in real time. RESULTS: All orthoses restricted motion to some extent. Generally, the collars ranked (from least restrictive to most restrictive): soft, Philadelphia, Philadelphia with extension, and sterno-occipital mandibular immobilizer brace. However, the differences were not usually large, and the collars did not restrict motion as much as previously reported. No collar restricted the motion of any of the subjects to less than 19 degrees of flexion-extension, 46 degrees of axial rotation, or 45 degrees of lateral bending, and most subjects demonstrated significantly more motion. CONCLUSIONS: Although cervical orthoses can be helpful for other reasons, they do not provide a high level of mechanical restriction of motion. Additionally, the restriction they do provide can vary widely between people. Prescribing physicians should consider the relative merits of the various orthoses before deciding whether they will meet a patient's needs. The differences between the collars tested may not be enough to justify one of the more expensive or less comfortable collars.

Adult↗

Intussusception secondary to Meckel's diverticulum detection with Tc-99m monoclonal antibodies to granulocytes (Leukoscan).

A case of Meckel's diverticulum causing intussusception in an 8-year-old boy is presented. The Meckel's diverticulum was detected by using a Tc-99m-labeled antigranulocyte monoclonal antibody MN3 (Leukoscan; Immunomedics, Morris Plains, NJ), which is under clinical evaluation for the detection of atypical appendicitis at the authors' institution. Pathologic evaluation confirmed Meckel's diverticulitis with ileal-ileal intussusception.

Antibodies, Monoclonal↗

Effect of amygdaloid kindling on rat striatal dopamine D1- and D2-receptors.

The effect of kindling on dopaminergic (DA) neurotransmission was assessed by measuring dopamine D1- and D2-receptor binding in the dorsal and ventral striatum of rats either 2 hours (short-term) or 3-4 weeks (long-term) after the last kindled seizure. Kindling did not have any significant long-term effect on DA D2-receptor Kd or Bmax values in the dorsal or ventral striatum or on DA D1-receptor parameters in the dorsal striatum. The short-term effect of kindled seizures was to abolish the asymmetry in DA D2-receptor density observed in the dorsal striatum of control rats. DA D1-receptor density was also increased in the dorsal striatum contralateral to the kindled amygdala of short-term rats. The short-term effects support the notion that limbic seizures can modify the lateral imbalance of DA activity in the striatum.

Amphetamine↗

Effect of amygdaloid kindling on [3H]dopamine and [14C]acetylcholine release from rat prefrontal cortex and striatal slices.

The involvement of the dopaminergic (DA) systems in the control of limbic kindled seizures is ill defined. The effects of kindling on DA activity may have been overlooked in the past, because of its subtle unilateral occurrence and/or the variance of the endogenous imbalance of DA activity in normal animals. In the present study rats were screened for their endogenous DA imbalance using amphetamine-induced rotational behaviour. Electrical or sham kindling was applied in the hemisphere with the higher endogenous DA activity. Sections of the bilateral prefrontal cortex and dorsal and ventral striatum were dissected either 2 hours or 21 days after the final seizure and the electrically stimulated release of [3H]DA and [14C]acetylcholine (ACh) determined. Release was also measured in the presence of quinpirole or sulpiride to assess the activity of pre- and postsynaptic DA D2-receptors. Long-term effects of kindling consisted of facilitation of ACh release in the ventral striatum contralateral to the kindled amygdala and bilateral depression of DA release in the prefrontal cortex. Kindling therefore produced area specific changes in neurotransmitter systems giving rise to increased pro-convulsive cholinergic activity in the ventral striatum and decreased anti-convulsive dopaminergic activity in the prefrontal cortex.

Acetylcholine↗

Physiological factors in infantry operations.

Male infantry soldiers (n = 34) were studied before, during, and after a 5-day simulated combat exercise. During the exercise, subjects were rated on their field performance by senior infantry non-commissioned officers. Prior to the exercise, direct measures of body composition and maximal oxygen uptake were obtained. Before and after the exercise the Army Physical Fitness Test and various measures of anaerobic capacity (Wingate and Thorstensson tests) and muscular strength (isometric and isokinetic) were obtained. Results showed no significant decrement in field performance during the exercise. Upper-body anaerobic capacity and strength declined following the exercise, although the results for upper-body strength were not consistent on all measures. Field performance was significantly correlated with measures of upper-body anaerobic capacity and strength. Upper-body strength and anaerobic capacity appear to be important for infantry operations and subject to declines during combat operations.

Adolescent↗

Comparison of a quantitative treadmill exercise score with standard electrocardiographic criteria in screening asymptomatic young men for coronary artery disease.

A computer-derived treadmill exercise score that quantifies the electrocardiographic response to exercise has been reported to have a high sensitivity (87 per cent) and specificity (92 per cent) in patients with a high prevalence of coronary artery disease. To test its accuracy in young, asymptomatic men with a low prevalence of coronary artery disease, we evaluated the responses of 377 military officers (mean age, 36.6 years) by two independent methods. According to standard electrocardiographic criteria, 45 of the subjects (12 per cent) had positive tests, whereas the treadmill exercise score indicated that only 3 (less than 1 per cent) had positive tests. Since two of these three had left ventricular hypertrophy and met only the criteria for the latter without associated coronary artery disease, the treadmill exercise score predicted that only 1 of 377 subjects would have clinically important coronary artery disease. Coronary arteriography, performed in 10 persons with the most positive scores on standard treadmill tests and the highest scores for risk factors, showed that nine subjects did not have coronary artery disease and that one had single-vessel disease (the same subject who the treadmill score predicted would have mild disease). The treadmill exercise score appears to improve the diagnostic specificity of exercise electrocardiography and may be more useful than values on standard stress tests in screening asymptomatic populations for coronary artery disease.

Adult↗

The production of terminal deoxynucleotidyl transferase (TdT) positive cells in cultures of human pluripotent hemopoietic progenitor cells.

A transient increase in terminal deoxynucleotidyl transferase positive (TdT+) cells was observed during the early phase of (less than or equal to day 5) cultures supporting the growth of pluripotent myeloid progenitor cells (CFU-mix). T-cell growth-promoting medium and erythropoietin were not required. The rapidity with which TdT+ cells appeared in cultures and the results of cultures where TdT+ cells were high initially (greater than 800 cells/culture) were not consistent with their having been produced by proliferation of pre-existing TdT+ cells from the bone marrow inoculum. The results suggest production of TdT+ cells from a TdT-negative precursor either by altered enzyme expression or by production of TdT+ progeny.

Cell Division↗