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Biomedical subjects

H L Frankel

Publications and source records attributed to H L Frankel.

At least 55 records · Page 3Linked to original sources
PubMed1989

Pharmacodynamics and pharmacokinetics of the oral antispastic agent tizanidine in patients with spinal cord injury.

The efficiency and duration of action of a single oral dose (8 mg) of tizanidine in patients with spinal cord injuries were determined by studying its antispastic, cardiovascular and sedative effects along with its pharmacokinetic profile in five tetraplegic and five paraplegic patients. After the administration of tizanidine, there was a reduction in spasticity in both groups within half an hour, with the effects lasting for 3 to 4 hours. There was no rebound increase in blood pressure. There was a greater increase in sedation in the tetraplegics than in the paraplegics. Plasma tizanidine levels rose within half an hour after dosing and peaked at one hour. The levels had fallen to 15 percent by 6 hours. The plasma half-life was 2.7 +/- 0.06 hours. We conclude that oral tizanidine has antispastic effects in patients with spinal cord injuries without affecting the power of non-involved muscle groups. It has minimal effects on blood pressure and it lowers heart rate. Side effects include sedation and dryness of mouth.

Administration, Oral↗
PubMed1989

Inhibition of wound repair by thymic hormones.

To further define the role of the thymus in wound healing, we studied the effects of two thymic hormones on fibroplasia in normal euthymic and in nude athymic mice. Groups of 10 mice underwent a 2.5 cm dorsal skin incision with subcutaneous placement of polyvinyl alcohol sponges. Starting on the day of wounding, the following daily injections were given: (1) thymopentin (TP5), an active synthetic pentapeptide of thymopoietin, a naturally occurring thymic hormone (1 microgram/day/IM); (2) thymulin or facteur thymique serique (FTS), a naturally occurring circulating thymic hormone (0.2 microgram/day/IM); (3) control saline solution (0.1 ml/day/IM). All mice were killed 4 weeks after wounding, and wound breaking strength and hydroxyproline content of the sponge granulomas were measured. The results show that both thymic hormones impaired wound breaking strength and reparative collagen synthesis in normal and athymic mice. The magnitude of the wound healing impairment induced by the two hormones was equal in the thymus-bearing and in the nude mice. The data support previous findings, which suggested that the thymus has an inhibitory effect on wound healing.

Animals↗
PubMed1988

Haemodynamic actions of clonidine in tetraplegia--effects at rest and during urinary bladder stimulation.

We studied the haemodynamic effects of clonidine (2 micrograms/kg/iv) in 7 tetraplegics and 7 normal subjects. Measurements of blood pressure, stroke volume, cardiac output and digital (finger) skin blood flow were made before and after clonidine for 60 minutes. Blood pressure, stroke volume and cardiac output did not fall in tetraplegics, unlike normals. Resting digital skin blood flow was higher in tetraplegics and fell after clonidine. In normal subjects however, an increase in digital skin blood flow occurred after clonidine. The pressor and digital vasoconstrictor responses to bladder stimulation were attenuated after clonidine. The inability of clonidine to induce a fall in blood pressure, stroke volume, cardiac output and cause peripheral vasodilation in tetraplegics is consistent with its central sympatholytic effects. Attenuation of the responses to bladder stimulation suggest an effect on spinal sympathetic neurones.

Adolescent↗
PubMed1988

Haemodynamic, hormonal and urinary responses to postural change in tetraplegic and paraplegic man.

We have studied the haemodynamic, hormonal and urinary effects of postural change in 6 tetraplegic patients, 6 paraplegic patients and 6 normal subjects. Measurements of blood pressure and heart rate, plasma renin activity, plasma aldosterone, urine volume and electrolyte excretion were made for 60 minutes while sitting and 60 minutes while recumbent. In tetraplegics the blood pressure was lower when sitting and rose during recumbency, unlike paraplegics and normal subjects. Plasma renin activity and aldosterone were higher in tetraplegics when sitting compared to normal subjects and did not fall during recumbency. Urine output increased significantly after recumbency in tetraplegics, but not in paraplegics or normal subjects. Both urinary sodium and potassium excretion were lower in tetraplegics and higher in paraplegics compared to normal subjects when sitting. In paraplegics the fall in both sodium and potassium excretion did not appear to be related to change in posture. Our observations indicate that recumbency induces a diuresis in tetraplegics but not in paraplegics or in normal subjects. The diuresis in tetraplegics may be related to the accompanying haemodynamic and hormonal changes induced by recumbency.

Aldosterone↗
PubMed1988

Vascular effects of clonidine in patients with tetraplegia and unilateral brachial plexus injury.

Evidence from studies in both animals and in tetraplegics with complete cervical spinal cord transection and preganglionic lesion, indicates that clonidine lowers blood pressure predominantly by a centrally mediated action. We have investigated the haemodynamic basis of this action and performed additional studies in patients with unilateral brachial plexus injury and postganglionic lesions, to further determine the site and mechanism of its action. Blood pressure fell after clonidine in normal subjects but not in tetraplegics. In normal subjects, the fall in blood pressure was associated with a fall in cardiac output, due to a fall in both heart rate and stroke volume. Digital skin vasodilatation occurred after clonidine in normal subjects and only in the innervated limb in patients with unilateral brachial plexus injury. In tetraplegics and in the denervated limb in unilateral brachial plexus injury, there was no vasodilatation; instead a vasoconstrictor response occurred, due to the peripheral adrenoceptor action of clonidine. We conclude that the fall in blood pressure and cardiac output in normal subjects after clonidine were due to its central sympatholytic action. Digital skin vasodilatation after clonidine in normal subjects and the innervated limb in unilateral brachial plexus injury was due to the withdrawal of vasoconstrictor tone and requires intact descending sympathetic pathways.

Adult↗
PubMed1987

Neuroendocrine control of vasopressin secretion and its effect on blood pressure in subjects with spinal cord transection.

The osmotic and cardiovascular control of arginine vasopressin (AVP) secretion, and the effect of this hormone on cardiovascular regulation were assessed both in normal controls and in subjects with tetraplegia. Infusion of hypertonic saline caused a marked rise in blood pressure in the tetraplegics but not in the normal controls. Head-up tilt resulted in a greater AVP response in the tetraplegics than in the controls because of the additional hypotensive response in the tetraplegics. Infusion of AVP itself at physiological concentrations had little effect on blood pressure in the normal subjects but resulted in a marked rise in blood pressure in the tetraplegics. Tetraplegics therefore show appropriate release of AVP to both osmotic and cardiovascular stimuli but increased sensitivity to the pressor effects of this hormone.

Adult↗
PubMed1986

Renal vascular responses to saralasin in conscious chemically denervated rabbits and patients with tetraplegia.

To determine the relative contributions of direct angiotensin-II-like myotropism and sympathetic nerve stimulation to the partial agonist effect of saralasin, the renal vascular responses to i.v. saralasin (5, 10, 20 micrograms/kg/min) were assessed in normal conscious rabbits before and after sympatholytic treatment with guanethidine (24 mg/kg/day for 9 days) and in 6 chronic tetraplegic patients (0.5, 1, 5 micrograms/kg/min) before and after alpha-adrenoreceptor blockade with i.v. thymoxamine (1 mg/kg/h). In rabbits saralasin reduced effective renal plasma flow (ERPF) and glomerular filtration rate (GFR), and increased renal vascular resistance (RVR) without affecting mean arterial blood pressure (BP). Responses were similar in both groups, but recovery following saralasin was more prolonged after treatment with guanethidine. When 0.1 microgram/kg/min (one fiftieth of the smallest i.v. dose) was infused just proximal to the renal arteries in 4 conscious rabbits (chronically cannulated), renal perfusion fell and RVR increased. In tetraplegics saralasin produced a transient rise in BP and variable increase in RVR; neither response being altered by thymoxamine. These results suggest that saralasin-induced renal vasoconstriction is independent of central and peripheral sympathetic activation, and is probably due to an intrinsic angiotensin-II-like myotropic action.

Adult↗
PubMed1985

Physical ability in relation to anthropometric measurements in persons with complete spinal cord lesion below the sixth cervical segment.

A study was undertaken to determine the ability of patients with complete tetraplegia below cervical sixth segment to transfer in relation to their anthropometric characteristics. Thirty-six chronic patients were assessed and spasticity was measured. A discriminant function analysis was carried out to assess the extent to which a number of anthropometric and anatomical variables could predict the patients' final ability to effect a transfer. Using nine of the original 23 predictor variables it is possible to correctly classify a patient's eventual ability to transfer in 92% of cases.

Adolescent↗
PubMed1984

Rehabilitation after spinal cord injuries complicated by previous lesions.

Since Sir Ludwig Guttmann introduced the comprehensive modern clinical approach to the rehabilitation of spinal cord injured patients much experience has been accumulated. Modern spinal cord injuries centres have opened throughout the world, treating mainly acute spinal cord injuries in young patients. At Stoke Mandeville Hospital we have had the opportunity to treat several spinal patients who had suffered previous neurological or orthopaedic disorders. These complicated combinations affected the rehabilitation process and the presentations show clearly different aspects of the problem.

Achondroplasia↗
PubMed1984

The immediate pressor response to saralasin in man: evidence against sympathetic activation and for intrinsic angiotensin II-like myotropism.

The cardiovascular and hormonal effects of intravenous saralasin (0.5, 1 and 5 micrograms min-1 kg-1) were assessed in nine tetraplegic patients (with complete cervical spinal cord transaction above the sympathetic outflow) and in six normal subjects. In the tetraplegic patients, saralasin caused an immediate transient pressor response which was not dose-dependent and substantially greater than the pressor response in normal subjects. The pressor response in the tetraplegic patients was not accompanied by a rise in levels of plasma noradrenaline. In the tetraplegic patients, after alpha-adrenoceptor blockade with thymoxamine (1 mg kg-1 h-1), twice the dose of intravenous noradrenaline was needed to induce the same pressor response. The pressor response to saralasin (5 micrograms kg-1 min-1), however, was unaffected by thymoxamine. Saralasin caused minimal changes in levels of plasma renin activity and plasma aldosterone in both groups. There was no relationship between basal plasma renin activity and the pressor response in either group. We therefore conclude that the immediate transient pressor response to saralasin in man is not due to central sympathetic stimulation, is unlikely to be due to peripheral sympathetic activation and is probably the result of intrinsic angiotensin II-like myotropism.

Adult↗
PubMed1983

Autonomic neuropathy.

Explore the source record for details and available documents.

Autonomic Nervous System Diseases↗
PubMed1981

Paraplegia due to intervertebral disc lesions: a review of 57 operated cases.

In a review of 57 cases of paraplegia due to surgically confirmed disc protrusion (representing 0.9 per cent of all admissions to the National Spinal Injuries Centre), seven were in the cervical, 31 in the dorsal and 19 in the lumbar regions. Patients with dorsal disc protrusions treated by laminectomy had the worst neurological outcome. A recent decline in the incidence of neurological dysfunction following disc excision is noted and its probable causes discussed.

Female↗
PubMed1981

Renin and aldosterone release during sympathetic stimulation in tetraplegia.

1. The effect of endogenous sympathetic stimulation (induced by urinary bladder stimulation) and intravenous infusion of noradrenaline and isoprenaline on blood pressure, heart rate and levels of plasma renin activity and plasma aldosterone were studied in six tetraplegic patients. Data from infusion studies were compared with data from six normal subjects studied in an identical manner. 2. Bladder stimulation in the tetraplegic patients caused a marked rise in blood pressure and fall in heart rate, but no change in plasma renin activity or plasma aldosterone. 3. Noradrenaline infusion resulted in an enchanced pressor response in the tetraplegic patients when compared with the normal subjects. Heart rate fell in both groups. Plasma renin activity and plasma aldosterone did not change in either group. 4. Isoprenaline infusion caused a fall in both systolic and diastolic blood pressure in the tetraplegic patients, unlike the normal subjects in whom there was a rise in systolic and a fall in diastolic blood pressure. Heart rate and plasma renin activity rose in both groups. Plasma aldosterone did not change in either group. 5. We conclude that in tetraplegic patients neither endogenous sympathetic stimulation by bladder stimulation nor infusion of noradrenaline raises plasma renin activity. Isoprenaline increases plasma renin activity to the same extent as in normal subjects. Renin release mechanisms in tetraplegic patients therefore do not appear to be hypersensitive to catecholamines. Plasma aldosterone is not influenced by any of the stimuli.

Adult↗
PubMed1980

Spinal cord injuries due to diving.

One hundred and fifty patients with spinal cord lesions due to diving accidents were admitted to Stoke Mandeville Hospital between 1944--77. Most of the patients were young men, 65 had dived into the sea, 48 into swimming pools, 21 into rivers and 3 into lakes. Injuries due to diving into the deep end of swimming pools appear to have been eliminated in Great Britain but injuries due to diving into the shallow end of swimming pools and into the sea continue to occur. The public need further education about the dangers of diving.

Adolescent↗
PubMed1980

Severe hypertension in patients with high spinal cord lesions undergoing electro-ejaculation--management with prostaglandin E2.

Intra-arterial blood pressure (BP) and heart rate (HR) were continuously recorded in five patients with spinal cord injuries at different levels who were undergoing electro-ejaculation. In three patients with lesions at C7, C5 and T4 insertion of the electrode and electrical stimulation caused severe hypertension and bradycardia. In a patient with a T7/8 lesion and in another with a T10 lesion there were either moderate or minimal cardiovascular changes. Severe hypertension during electro-ejaculation is a serious problem in patients with high lesions and is probably part of the syndrome of autonomic dysreflexia. In the three patients with high spinal cord lesions the procedures were repeated during an intravenous infusion of Prostaglandin E2. Resting BP was lowered and resting HR raised. The level of BP recorded during electrical stimulation was substantially reduced. This enabled larger stimuli to be used for a longer period and resulted in successful ejaculation in two patients.

Adult↗
PubMed1980

Renin release during head-up tilt occurs independently of sympathetic nervous activity in tetraplegic man.

1. The role of the sympathetic nervous system in the release of renin during head-up tilt has been studied in five normal subjects and in four tetraplegic patients with cervical spinal-cord transection above the sympathetic outflow. Blood pressure, heart rate and concentrations of plasma noradrenaline, plasma adrenaline and plasma renin activity were measured during head-up tilt to 45 degrees before and after acute beta-adrenoreceptor blockade with intravenous propranolol. 2. In the normal subjects there were minimal changes in blood pressure during head-up tilt and there was a rise in both plasma noradrenaline concentration and plasma renin activity. After propranolol values of plasma renin activity at rest fell with little change occurring during head-up tilt. 3. In the tetraplegic patients there was a substantial fall in blood pressure during head-up tilt. Concentrations of plasma noradrenaline and adrenaline did not change but there was a marked increase in plasma renin activity. Values of plasma renin activity both at rest and during head-up tilt were unaffected by propranolol. 4. We conclude that in tetraplegic patients renin release during head-up tilt may occur independently of sympathetic nervous activity and is probably largely dependent on activation of renal vascular receptors.

Adult↗