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Biomedical subjects

F J Imms

Publications and source records attributed to F J Imms.

At least 37 records · Page 2Linked to original sources
PubMed1977

Falls in the elderly related to postural imbalance.

Two hundred and forty-three elderly people aged 60 to 96 years were questioned about their falls, and their sway was measured. For comparison sway was also measured in 63 younger subjects. Sway increased with age and was higher in women at all ages. There was no difference in sway between those with no history of falls and those who fell only because of tripping. In both sexes sway was significantly increases in people who fell because of loss of balance and in women whose falls were due to giddiness, drop attacks, turning the head, and rising from bed or a chair. This suggests that there is a physiological decline in postural control with advancing age and also a decline due to disease of the central nervous system.

Accidents, Home↗
PubMed1977

Voluntary isometric muscle strength of patients undergoing rehabilitation following fractures of the lower limb.

Isometric muscle strength was measured in 32 servicemen recovering from fractures of the lower limb. At the time when patients were admitted for rehabilitation there were marked reductions of strength in the injured limb of muscles acting at the hip, knee and ankle joints. Marked improvement of strength occurred during rehabilitation, but there were still significant differences between the limbs at the time of discharge from the rehabilitation unit.

Ankle Joint↗
PubMed1977

Responses of the cardiovascular system of the rat to alpha-and beta-adrenoceptor agonists.

1 The effects of intravenously infused phenylephrine and isoprenaline upon the cardiovascular system of the rat anaesthetized with pentobarbitone, have been investigated.2 Phenylephrine produces a dose-dependent rise in mean arterial blood pressure (MABP) that is due mainly to an increase in total peripheral vascular resistance (TPR), though at all doses tested cardiac output was invariably raised.3 The increase in cardiac output was due in each instance to an increase in stroke volume, heart rate being unchanged. This increase in cardiac output is probably brought about by effects of phenylephrine on the capacitance vessels rather than by an effect on the heart.4 Evidence is presented to show that the effects of phenylephrine are mediated largely by alpha-adrenoceptors, but that beta-adrenoceptors which affect TPR are also stimulated by the amine.5 Isoprenaline produces a dose-dependent fall in MABP that is due entirely to a fall in TPR since the cardiac output increases.6 Unlike phenylephrine, the increase in cardiac output obtained with isoprenaline was achieved by an increase in heart rate while stroke volume remained close to control values. It is contended that the augmented venous return required for the elevated cardiac output results in this case mainly from the isoprenaline-induced fall in TPR which enhances transfer of blood from arteries to the veins.7 Evidence is presented to show that the effects of isoprenaline are mediated mainly by beta-adrenoceptors.8 Under the present experimental conditions the adrenoceptor-mediated cardiovascular changes are little modified reflexly by the arterial baroreceptors.

Adrenergic alpha-Agonists↗
PubMed1977

Responses of the cardiovascular system of the rat to noradrenaline infusions and their modification by adrenoceptor blocking agents.

1 The effects of noradrenaline upon the cardiovascular system of the rat, anaesthetized with pentobarbitone, have been investigated.2 Noradrenaline produces a dose-dependent increase in mean arterial blood pressure (MABP) which is due entirely to an increase in cardiac output; total peripheral vascular resistance (TPR) remains unchanged.3 Following beta-adrenoceptor blockade the pressor response to infused noradrenaline is enhanced and is now due mainly to an increase in TPR; the increment in cardiac output is reduced.4 After alpha-adrenoceptor blockade the pressor response is greatly reduced; the residual increase in MABP is due solely to an increase in cardiac output.5 After ganglion blockade resting cardiac output and TPR both fall, resulting in a reduction in MABP. The pressor response to noradrenaline is enhanced and is now due to increases in both TPR and in cardiac output.6 The cardiovascular response of the anaesthetized rat to noradrenaline can be explained in terms of classical alpha- and beta-adrenoceptor stimulation by the amine; the unusual form of the response may be due to an effective predominance of beta-adrenoceptor-mediated effects in this species.7 It is suggested that the failure of exogenous noradrenaline to produce a rise in TPR results from a balance between the alpha-adrenoceptor-mediated increase and beta-adrenoceptor-mediated decrease in this variable. However, this proposed balance is lost if resting vasoconstrictor tone is reduced by ganglion blockade.

Adrenergic alpha-Antagonists↗
PubMed1976

Blood flow through the calf during recovery from fractures of the lower limb.

1. Venous occlusion plethysmography has been used to measure the blood flow in the calves of nineteen patients with fractures of the lower limb and in six normal control subjects. 2. The resting blood flows were significantly higher in the injured legs than in uninjured legs, irrespective of the site of injury. Flows in the uninjured limbs were similar to those of the control subjects. 3. During reactive hyperaemia after 10 min arterial occlusion, the increase of flows in both legs of the patients was significantly lower than in the control subjects. Because of the increased resting flow, the maximal flow in the injured leg was similar to that in the control subjects, whereas the maximal flow in the uninjured leg was significantly lower than in the control group. 4. The changes in resting flow cannot be accounted for by a change in the proportions of tissues in the limb but they may be explained by an increase of the flow through muscle secondary to a relative increase in the mass of slow to fast muscle fibres.

Adipose Tissue↗
PubMed1976

Physiological performance and work capacity of Sudanese cane cutters with Schistosoma mansoni infection.

Physiological tests of work performance and measurement of field productivity were made in 194 Sudanese cane cutters in order to study the effect of Schistosoma mansoni infection. The cane cutters were selected from two age ranges (16-24 and 25-45 years) and subdivided into three clinical groups: not infected, infected with, and infected without clinical signs of hepatosplenomegaly. Men infected with Schistosoma haemotobium, malaria (blood film), or with hemoglobin levels less than 10 g/100 ml were excluded. There was a statistically significant (P less than 0.002) higher mean hemoglobin concentration in those not infected but the mean difference was less than 1 g/100 ml. Submaximal responses to exercise on a stationary bicycle ergometer, oxygen intake, ventilation, tidal volume, cardiac frequency and estimated maximal aerobic power output calculated both in absolute terms and relative to lean body mass and leg volume were similar in the six groups of cane cutters. No significant differences were found in physique, body composition or in thermoregulatory function tests. The cane cutters were found to have little natural acclimatization to heat in terms of sweating capacity when compared with a group of fully acclimatized Sudanese soldiers. The mean productivity (mean daily weight of cane cut per man) was significantly correlated with the individual's estimated maximum aerobic capacity determined in the laboratory, but not with the degree of S. mansoni infection. The noninfected group was less "efficient" (mean productivity:oxygen intake) during cutting than the infected groups but a larger proportion of the noninfected were in their first season of cutting. There was a positive correlation between the number of seasons' cutting experience and the individual's age, degree of infection and mean productivity. Cane cutters studied in this investigation were a relatively fit, active population from whom the more seriously ill were excluded. These results do not, therefore necessarily reflect the effects of S. mansoni on physiological work capacity and productivity of more static populations in areas of high endemicity.

Adolescent↗
PubMed1976

Energy expenditure during walking in patients recovering from fractures of the leg.

The oxygen consumption during walking has been studied in 13 patients recovering from fractures of the leg and in 8 control subjects. Oxygen consumption of normal subjects when walking at velocities of 0.5, 1.0 and 1.5 m sec-1 was 8.0, 9.8 and 13.6 ml kg-1 min-1 respectively. For subjects walking on crutches with the leg encased in a Plaster of Paris cast, the oxygen consumption at these velocities was 12.0, 17.5 and 25.3 ml kg-1 min-1 respectively. The energy cost of walking was reduced when the cast was removed, when the crutches were replaced by sticks and when all aides were discarded. When all aids had been discarded the energy expenditure was normal at 0.5 and 1.0 m sec-1 but was still significantly higher at faster velocities.

Adult↗
PubMed1975

Pituitary-adrenal response to static exercise in man.

1. Changes in plasma concentrations of catecholamines and cortisol were measured before and after static exercise performed by the subject pushing with both legs against a strain-gauge bar. No marked changes in plasma catecholamine were observed but plasma cortisol increased after the subject pushed for 3 min at 50% of maximum force. 2. Holding a 20 kg weight for 5 min in one hand caused a rise in plasma cortisol and in plasma ACTH but no changes in growth hormone were observed.

Adrenocorticotropic Hormone↗