Biomedical subjects
Publications and source records attributed to E Brooks.
A case report of a 10-year-old child with a central fracture-dislocation of the hip, managed by open reduction is presented, with a long-term result. The rarity of this injury in children is discussed, with the possible complications of inadequate joint congruity and potential growth injury.
The purpose of these experiments was to determine the effects of acute beta-blockade on the kinetics of oxygen uptake (VO2), expired carbon dioxide (VCO2), and expired ventilation (VE) in the transition from rest to submaximal exercise. Six male subjects exercised for 6 min on a cycle ergometer (60 W) initiated as a square wave from rest on two occasions. The beta-blockade experiment began 60 min after the subject ingested propranolol hydrochloride (1 mg.kg-1 BW) while the second experiment served as control with the treatment order counterbalanced. Ventilation and gas exchange were monitored by open circuit techniques and the data were modeled with a single-component exponential function using a time delay. No differences existed (p greater than 0.05) in the steady state VO2, VCO2, or VE nor the kinetics of VCO2 and VE between treatments. However, the rate of adaptation of VO2 toward steady state was significantly slowed (p less than 0.05) with beta-blockade. These data suggest that acute beta blockade results in diminished VO2 kinetics in the transition from rest to steady-state exercise. We hypothesize that the mechanism to explain this finding is a slowed time course of cardiac output adjustment at the beginning of exercise.
Controversy exists concerning the effects of acute beta-adrenergic blockade on ventilation during exercise. Hence, the purpose of this study was to determine the effects of acute beta blockade on ventilation and gas exchange during incremental exercise. Nine male subjects underwent incremental exercise on a cycle ergometer (30 W.min-1) to exhaustion, with one trial being performed 60 min after the subject ingested propranolol hydrochloride (Inderal 1 mg.kg-1 BW) while the second test served as control. The treatment order was counterbalanced to preclude any ordering effect on the results, and 1 week separated the tests. Ventilation and gas exchange were monitored by open circuit techniques. No difference (p greater than 0.05) existed in VE, % Hb sat, VCO2, ventilatory threshold, and VE/VCO2 between treatments at the same exercise stage. VO2max was lowered from 3.82 to 3.26 l.min-1 (p less than 0.05) and HRmax was reduced from 190 to 150 bpm (p less than 0.05) as a result of beta blockade. These data suggested that acute beta blockade had no effect on exercise ventilation, but decreased HRmax at comparable work rates. In addition, VO2max and exercise time to exhaustion were hindered, probably due to beta blockade limitation of HRmax, and, thus, oxygen transport.
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Successful percutaneous transluminal coronary angioplasty is achieved by fracture of the atheromatous plaque and perhaps dilatation of the arterial walls to increase the luminal diameter of the artery. Because this "controlled" injury stimulates platelet adhesion on the subendothelial matrix, the use of dextran-40 in addition to heparin has been advocated. The overall incidence of Dextran-induced anaphylactoid reactions at our institution was 0.6% and of severe life-threatening reactions, 0.2%. With the recent doubts cast on the efficacy of dextran-40, the question arises regarding its routine use in PTCA.
The purpose of this study was to analyze differences in the activity of medullary respiratory neurons in the unanesthetized, intact cat during wakefulness and non-rapid-eye-movement (NREM) sleep. We studied single respiratory neurons located within a 1-2 mm deep, 8-10 mm long zone that followed, and included in its dorsal aspect, the retrofacial and ambiguus nuclei. The analysis of variance was used to detect respiratory activity, and cycle-triggered histograms were plotted. The respiratory signal strength and consistency of the respiratory activity were quantified with the eta 2 statistic. We determined for each breath in wakefulness and NREM sleep the average discharge rate during the active phase of the cell, the number of action potentials during the active phase of the cell, and durations of both the cycle and inspiration. Differences in discharge rates and in the number of discharges between wakefulness and NREM sleep were tested with the t test. A bimodal distribution of eta 2 values for the population of neurons indicated there were two groups of respiratory cells: those with eta 2 values less than 0.3 and those with values greater than 0.3. The former we call weak respiratory cells; the latter, strong respiratory cells. Strong and weak cells were classified further as inspiratory or noninspiratory on the basis of the shape of their cycle-triggered histograms. Within the class of strong inspiratory cells, those with the highest eta 2 values 1) reached their peak discharge rate early, 2) discharged at high rates throughout inspiration, and 3) were inactive during expiration. The values of these variables diminished progressively in inspiratory cell groups with lower eta 2 values. Most cells were less active in NREM sleep than in wakefulness. Similar proportions of weak and strong cells and inspiratory and noninspiratory cells were affected by sleep. The reduction in sleep of the activity of strong inspiratory cells was consistent with a general relationship between this activity and the duration of inspiration. Lower discharge rates were associated with longer breaths; higher rates with shorter breaths. This relationship existed within both NREM sleep and wakefulness, and the plot of the relationship across these states formed a continuous function. The reduction in discharge rate in sleep was greater for weak than for strong inspiratory cells: the correlation coefficient between percent change in rate and eta 2 values was -0.636 for inspiratory cells, but it was not significant (-0.265) for noninspiratory cells.(ABSTRACT TRUNCATED AT 400 WORDS)
Numerous studies have reported that following intense exercise the rate of blood lactate (La) disappearance is greater during continuous aerobic work than during passive recovery. Recent work indicates that a combination of high- and low-intensity work may be optimal in reducing blood La. We tested this hypothesis by measuring the changes in blood La levels following maximal exercise during four different recovery patterns. Immediately following 50 S of maximal work, subjects (n = 7) performed one of the following recovery treatments for 40 min: 1) passive recovery (PR); 2) cycling at 35% maximal O2 uptake (VO2 max) (35% R); 3) cycling at 65% VO2 max (65% R); 4) cycling at 65% for 7 min followed by cycling at 35% for 33 min (CR). The treatment order was counterbalanced with each subject performing all treatments. Serial blood samples were obtained throughout recovery treatments and analyzed for La. The rate of blood La disappearance was significantly greater (P less than 0.05) in both the 35% R and CR when compared with either the 65% R or PR. No significant difference (P greater than 0.05) existed in the rate of blood La disappearance between the 35% R and CR. These data do not support the hypothesis that exercise recovery at a combination of intensities is superior to a recovery involving continuous submaximal exercise in lowering blood La following maximal work.
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Explore the source record for details and available documents.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Hexabrix, a low-osmolality radiographic contrast agent consisting of the meglumine and sodium salt of ioxaglic acid (600 mOsm/kg), was evaluated in 50 children undergoing cardiac catheterization in a randomized double-blind manner. In comparison with a conventional radiographic contrast agent (Renografin-76), Hexabrix produced a marked reduction in the pain or discomfort after the injection. Neither agent produced any significant change in pulse or respiratory rates or blood pressure. Changes in left and right ventricular pressures were small and comparable for both groups. Significant dysrhythmias were not noted. There was no evidence of deterioration in renal or hepatic function in either group. Serum LDH and CPK increased comparably with both contrast agents but without any definite evidence of myocardial injury. Postinjection increases in serum osmolality were slightly, but not significantly, higher with Renografin. In the first few hours following the procedure there was an increase in circulating segmented neutrophils and a reciprocal decrease in lymphocytes; this was transient and gone by 24 hours. Radiographic image quality was judged good or excellent in almost all cases. Hexabrix is a contrast agent that is significantly better tolerated than conventional agents and is associated with no greater incidence of side-effects while producing radiographic images of equivalent quality.
Two sterols in autopsied whole lung specimens obtained from Pneumocystis carinii pneumonia patients were detected by gas-liquid chromatography and their structures were elucidated by mass spectrometry and nuclear magnetic resonance spectrometry. Both were in the lanosterol series; the C31 sterol, with a methyl group at C-24, was identified as euphorbol, and the more abundant C32 sterol, with an ethyl group at C-24, is given the trivial name pneumocysterol.
Rapidly changing technology and the trend toward specialization make continuing education (CE) vital for today's nurses. Various methods to assess CE needs of nurses are described in the literature. This article outlines an assessment strategy implemented to determine staff nurses' perceptions of their learning needs. In addition, head nurses and clinical directors were surveyed regarding their perceptions of the staff nurses' learning needs. The chosen strategy used limited resources to contact a large number of nurses within a short time frame. Results indicated that the three groups surveyed perceived similar learning needs for staff nurses.