Joshua Harold Burn: 6 March 1892-13 July 1981.
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History, Modern 1601-↗
Biomedical subjects
J M Walker
Publications and source records attributed to J M Walker.
Acute effects of ketanserin on left ventricular function, metabolism and coronary blood flow.
An acute intravenous bolus of 10 mg ketanserin (a specific 5-HT antagonist) caused an abrupt fall in left ventricular systolic pressure of 17 +/- 9.2 mm Hg (P less than 0.025) in ten patients undergoing cardiac catheterisation for chest pains. A fall in pulmonary artery diastolic pressure of 2.1 +/- 0.74 mm Hg (P less than 0.02) was also observed. No changes in resting heart rate occurred and the response to pacing was largely unmodified by ketanserin, except for a reduction in pulmonary vascular resistance (3.70 +/- 1.27 units to 2.97 +/- 1.44 units, P less than 0.05), at the fastest rate (136 +/- 3 beats/min). At the highest pacing rate coronary sinus blood flow fell (83 +/- 12 ml 100 g-1 min-1 to 68 +/- 8 ml 100 g-1 min-1, P less than 0.05), as did myocardial oxygen consumption (18 +/- 2 ml-1 min to 14 +/- 1 ml min-1, P less than 0.05) after the drug. No changes in the parameters of left ventricular contractile function could be attributed to ketanserin, save for a modest increase in the ejection fraction (48 +/- 6% to 57 +/- 6%, P less than 0.05) in seven patients. There were no alterations in myocardial metabolism of lactate, pyruvate, hydroxybutyrate, glycerol nor free fatty acids after ketanserin. The findings are consistent with a peripheral site of action of this drug and its blood pressure lowering effect in the subjects suggest a non-specific hypotensive action rather than an anti-hypertensive effect.
Adult↗
Chromatin associated protease from calf thymus.
We have identified and purified a chromatin bound protease from calf thymus. The purified enzyme cleaves histone H1 when whole histone is used as substrate. The enzyme is inhibited by Soya bean trypsin inhibitor, but not by PMSF, EDTA, pepstatin or Ellman's reagent. Further studies have shown that H1(0) and histone H5 are also cleaved by this enzyme, and that when HMG 1 and 2 are used as substrate HMG1 alone is degraded to give specific degradation products. We have also shown that the enzyme co-isolates with whole histone prepared by acid extraction of calf thymus nuclei, but interestingly it is not present in whole histone samples prepared in the same manner from pig thymus. A second chromatin bound protease which specifically cleaves histone H3 when whole histone is used as substrate has also been identified during the course of this work.
Animals↗
Putative high mobility group (HMG) non-histone chromosomal proteins from wheat germ. Isolation, characterisation and partial sequence analysis.
Four proteins have been isolated from wheat germ by methods analogous to those used to isolate HMG proteins from animal tissue. All four proteins have been shown to be chromosomal in origin. Although amino acid analyses show that three of these proteins have compositions similar to those of the mammalian HMG proteins, N-terminal sequence analyses of these proteins show an absence of sequence homology with any of the mammalian HMG proteins.
Amino Acid Sequence↗
Endogenous opioids: biology and function.
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Adrenal Medulla↗
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.
Adult↗
The effect of haemolysis on some clinical chemistry parameters in the marmoset (Callithrix jacchus).
The effect of haemolysis on the levels of commonly analysed plasma constituents was investigated in the common marmoset. Results were divided into a) low levels of extra haemolysis (less than 2 g/l plasma haemoglobin) and b) high levels of extra haemolysis (greater than 2 g/l plasma haemoglobin). Mean changes in plasma constituent levels were examined and the correlation with increased haemolysis measured. Large changes in malate dehydrogenase and lactate dehydrogenase were found at low levels of haemolysis. With higher levels of haemolysis there were statistically significant changes in the levels of alanine aminotransferase, isocitrate dehydrogenase, glutathione reductase, bilirubin, aspartate aminotransferase and sorbitol dehydrogenase. The significance of these findings is considered in relation to the interpretation of changes of plasma constituents as indicators of tissue/organ damage.
Animals↗
Stabilities of some constituents of marmoset (Callithrix jacchus) plasma under various conditions of storage.
The stability of various marmoset (Callithrix jacchus) plasma constituents was investigated after storage at room temperature, 4 degrees C, and -20 degrees C. The method of sequential analysis ensured that the between-run bias of the methods of analysis used was drastically reduced, and the definitions of stability were linked to the imprecision of these methods. Optimal conditions for storage for as long as 48 h depended on the analyte being measured. Room temperature was optimal for cholinesterase and acetylcholinesterase; 4 degrees C for protein, albumin, alanine aminotransferase, isocitrate dehydrogenase, sorbitol dehydrogenase, lactate dehydrogenase, and glutamate dehydrogenase; and -20 degrees C for glutathione reductase and alkaline phosphatase. For aspartate amino-transferase and gamma-glutamyltransferase, either 4 degrees C or -20 degrees C would be suitable. Reasons are advanced for some conflicting reports in the published work, and we emphasize the need to investigate each analyte and species separately.
Animals↗
[3H]Dynorphin A binds selectively to guinea pig brain.
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Animals↗
[3H] dynorphin binding to guinea pig and rat brain.
[3H] Dynorphin can be shown to bind to the brains of both rat and guinea pigs with approximately 50% specific binding. Characterization of the binding in terms of multiple opiate receptor types supports the kappa selectivity of dynorphin in guinea pig. However, in rat brain, a substantial proportion of the [3H] dynorphin binding is displaced by morphine, suggesting a mu as well as kappa component. Consequently, in rat, dynorphin may show effects at both mu and kappa receptors in vivo.
Animals↗
A solid state device for measuring sensitivity to thermal pain.
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Animals↗
Phase relations between carotid pressure and ongoing electrocortical activity.
The behavioral significance of changes in the cardiovascular system has been a major source of controversy in psychophysiology. In view of this, it is surprising that so few studies have examined the relationship between cardiac events and electrocortical (EEG) activity in human subjects. In the present study, this relationship was examined by comparing phase, amplitude and frequency of EEG activity sampled during systolic and diastolic pressure recorded from the carotid artery of resting subjects. The results indicated that rhythmic oscillations of the EEG (particularly those in the alpha range) were time-locked to the carotid pressure wave, and EEG samples taken during systolic and diastolic pressure were distinctly out of phase. In addition, EEG activity sampled during systolic pressure was comprised of slower frequencies than EEG activity sampled during diastolic pressure. It was suggested that the relationship between cardiac events and behavior may be mediated in part by influences of the cardiovascular system on electrocortical rhythms.
Adolescent↗
Academic tenure: what does it mean?
Tenure is an integral aspect of academia. Because tenured faculty give esteem to individual physical therapy programs and to the profession as a whole, understanding the process of attaining tenure is vital to all physical therapy educators. Tenure in universities is described, and the process of attaining tenure is outlined. Criteria for tenure, factors related to transfer of faculty between universities, and considerations for terminating tenured faculty are also discussed. Departmental chairmen have a responsibility to ensure that the faculty members understand the tenure process and are given the opportunity to meet tenure criteria.
Faculty, Medical↗
Profile of physical therapy educators in five countries.
Physical therapy educators in Australia, Britain and Ireland, New Zealand, Nigeria, and South Africa were surveyed to develop a profile of physical therapy educators in these countries and to permit comparison with data on US and Canadian educators. Faculty members (N = 154) from 18 programs responded to a questionnaire consisting of 22 items related to education, experience, and professional activities. Most of the respondents (79%) held an entry-level qualification at the diploma or certificate level, and compared with US educators, a much lower percentage held academic degrees of any kind. Similarities between the respondents and US and Canadian educators were found in percentages of women, of those under 40 years of age, of those currently enrolled in academic programs, and of those with tenure; differences were found in hours spent teaching and number of faculty members who had published in the last two years. Understanding these similarities and differences may facilitate international faculty exchange programs and employment.
Adult↗
Straight-leg-raising test. Comparison of three instruments.
The purpose of this study was to compare three instruments in the assessment of the passive straight-leg-raising test: a standard plastic goniometer, a flexometer, and a tape measure. Hip flexion angles at the initial point of pelvic tilt were measured in 10 healthy subjects. All three methods showed excellent intrasession reliability with alpha coefficients greater than .94. The intersession reliabilities were identical for the goniometer and the flexometer (.88) and were higher than the reliability of the tape measure (.74). The tape measure had improved intersession reliability (.93) when a distance was used for calculation of the angle. Significantly lower hip flexion angles were obtained with the trigonometric method through use of tape measures than from use of either of the other two instruments. The flexometer is recommended for use in assessment of passive straight leg raise because it permits measurement by a single therapist without assistance.
Adult↗
Comparison of normal and abnormal human fetal hip joints: a quantitative study with significance to congenital hip disease.
The presence, extent of abnormality, and measurement data in hips from six fetuses with congenital deformities and seven normal fetuses with 12 aberrant hips were compared with similar data from 140 normal fetuses. Six hips were abnormal on naked eye examination in fetuses with polycystic kidneys, multiple deformities, or cyclopia. Hips graded normal in two fetuses with cardiac defects were found to have dysplasia, greater on the left side, when measurement data were compared. Aberrant features observed resembled that reported in congenital hip disease. Although no joints were frankly dislocated, six hips were subluxated with marked deformity. Only two assessed abnormal hips did not have values outside normal limits for their comparison age group, and joints from six fetuses had some values that exceeded normal limits by 2 SD. In only two fetuses were the femoral angle values outside normal limits indicating that femoral angles alone may be poor criteria of hip dysplasia. Quantitative data for normal fetuses permit more precise evaluation of morphologically abnormal joints and enable detection of dysplasia not apparent on naked eye examination.
Diseases in Twins↗
A thiol inhibitor produced by Aspergillus niger.
A low molecular weight inhibitor of the thiol proteases papain and bromelain has been identified and partially purified from the culture filtrates of Aspergillus niger. Further studies have shown that this inhibitor reacts with compounds containing a free thiol group and as such it is capable of inhibiting other enzymes that contain a functional thiol group at their active site.
Aspergillus niger↗
Energy cost of walking and of wheelchair propulsion by children with myelodysplasia: comparison with normal children.
The oxygen consumption of 15 myelodysplastic children during walking and propelling a wheelchair was studied. In comparison to normal children, they walked more slower and consumed more oxygen per meter, but had a similar rate of oxygen consumption. A swing-through gait pattern was 33 per cent more energy-efficient than a four-point gait pattern for these children. Wheelchair propulsion produced velocities and energy efficiencies similar to normal children walking. Oxygen consumption and velocity measurements were found to be significantly related to the clinical factors of level of lesion and strength of hip and knee extension. Regression lines and equations are presented to permit prediction of energy cost and efficiency from heart-rate data of myelodysplastic children.
Child↗