Biomedical subjects

R D Fealey

Publications and source records attributed to R D Fealey.

29 records · Page 2Linked to original sources

PubMed1986

Pharmacodynamics of midodrine, an antihypotensive agent.

Midodrine is an orally active adrenergic agonist useful in the treatment of hypotension. We have investigated the pharmacodynamics of its active metabolite after oral midodrine therapy in nine patients with severe orthostatic hypotension. Peak plasma levels of the metabolite were reached in 60 to 90 minutes and ranged from 25 to 56 ng/ml. The mean values for distribution volume, plasma clearance, and t1/2 were 4.0 L/kg, 23 ml/min/kg, and 2.1 hours, respectively. Heart rate increased after 5 to 10 mg doses and the increases were statistically significant (P less than 0.05) at 120 minutes. An apparent increase in blood pressure was not statistically significant. The patients said that they felt better.

Administration, Oral↗

PubMed1985

Chronic idiopathic anhidrosis.

We describe the cases of eight patients with chronic idiopathic anhidrosis. These patients were heat intolerant and became hot, flushed, dizzy, dyspneic, and weak but did not sweat when the ambient temperature was high or when they exercised. Four patients had preganglionic sudomotor lesions and in the remaining 4 the lesion appeared to be postganglionic. The patients did not have orthostatic hypotension, other evidence of generalized autonomic failure, or symptomatic somatic neuropathy. One patient regained thermoregulatory sweat function and no patient's condition progressed to generalized autonomic failure. Chronic idiopathic anhidrosis appears to be distinctly different from other autonomic neuropathies that tend to carry much poorer prognoses.

Adult↗

PubMed1985

Gastrointestinal motility disturbances in patients with orthostatic hypotension.

Orthostatic hypotension syndromes may be associated with visceral denervation, resulting in disturbances of the gastrointestinal and urinary systems. This report analyzes the findings in 9 patients with neurogenic orthostatic hypotension and gastrointestinal symptoms. Antral and proximal small intestinal motor dysfunction was demonstrated in all patients: a significant reduction (p = 0.007) in the number of interdigestive motor complexes during 3 h of fasting (mean 0.4 vs. 1.3 controls); absence of gastric component in interdigestive motor complexes observed; incoordination of fasting and fed antral activity; and development of nonpropagating bursts of phase III-like activity in the intestine that were of at least 2-min duration, high amplitude and frequency, and associated with tonic elevations in baseline pressure. These motor abnormalities may provide a potential means for the diagnosis of impaired autonomic supply to the upper gut.

Adult↗

PubMed1984

Effect of traumatic spinal cord transection on human upper gastrointestinal motility and gastric emptying.

Whether transection of the spinal cord, above the level of the sympathetic outflow to the gastrointestinal tract, alters human upper gastrointestinal function is yet unknown. In 5 patients with complete high-cord transection (neurologic level above T1), 3 patients with complete low-cord transections (neurologic level T10 or below), and 4 age- and sex-matched healthy controls, the duration of the phases and cycle length of the interdigestive motor complex were similar. However, the percentage of phase III's of the interdigestive motor complex that originated in the antrum and propagated to the duodenum was significantly decreased in patients with high-cord transections compared with healthy subjects (38% vs. 90%; p less than 0.05), but was similar in patients with low-cord transections and normal controls (75% vs. 90%). After liquid meals, 3 of the 3 high-cord patients tested had reduced cumulative gastric emptying at 60 min postprandially compared with healthy subjects. Thus, interruption of the cervical cord above the level of the sympathetic outflow to the gastrointestinal tract disturbs normal interdigestive antral-duodenal motor coordination and may delay postprandial gastric emptying of liquid meals.

Adult↗

PubMed1983

Acute panautonomic neuropathy.

Two patients with acute panautonomic neuropathy had severe impairment of sympathetic and parasympathetic function of acute onset. Autonomic tests suggesting a postganglionic lesion and direct evidence of loss of unmyelinated and small myelinated fibers on nerve biopsy were found in Patient 1. There was a selective loss of small myelinated and unmyelinated nerve fibers; C potential was absent in the in vitro compound action potential; dopamine-beta-hydroxylase activity was unmeasurable. No definite abnormalities were found on the nerve biopsy of Patient 2. The acute panautonomic neuropathies appear to comprise a spectrum of somatic and autonomic involvement.

Acute Disease↗

PubMed1983

Quantitative sudomotor axon reflex test in normal and neuropathic subjects.

We have quantified postganglionic sweat output in human subjects resulting from axon reflex stimulation using acetylcholine electrophoresis. Dehumidified nitrogen of controlled temperature and flow rate was passed through an acrylic plastic chamber placed over a defined area of skin. Sweat droplets were evaporated; humidity change was sensed by a narrow-range humidity sensor housed in a temperature-controlled compartment and was plotted on a chart recorder. The time integral (area under the curve) was continuously integrated and converted to absolute units using a derived equation. Because stimulation and recording were simultaneous, an accurate determination of the latency of the sweat response was also possible. Quantitative sudomotor axon reflex tests were performed on the left forearm and foot of 33 female and 29 male normal subjects aged 11 to 69 years. Acetylcholine, 10%, was electrophoresed for 5 mA-minutes in the forearm and 10 mA-minutes in the foot, and recording was continued for an additional 5 minutes. The mean sweat output in males was 2.7 and 3.0 times that in females in forearm and foot, respectively (p less than 0.0001). Studies in selected autonomic neuropathies confirm that quantitative sudomotor axon reflex tests will detect postganglionic sudomotor abnormalities sensitively and reproducibly.

Acetylcholine↗

PubMed1983

Not 'indifference to pain' but varieties of hereditary sensory and autonomic neuropathy.

Three children, from different kinships, with generalized insensitivity to pain, showed unusual manifestations of congenital, presumably inherited, sensory and autonomic neuropathy. The first child appeared to have a syndrome resembling those previously described as congenital indifference to pain, congenital universal loss of pain sensation from infancy without other apparent neurological deficit. Unlike most types of hereditary sensory and autonomic neuropathies (types I, II, III), but like type IV, she had normal sensory nerve action potentials. Abnormalities of sudomotor function and of somatosensory evoked potentials were demonstrated. A severe decrease in the number of sural nerve A delta fibres and a small reduction in C fibres were demonstrated morphometrically. An abnormality of C fibres was confirmed by a marked reduction in nerve dopamine-beta-hydroxylase activity. The plasma and CSF concentrations of beta endorphins, substance P and several other neuropeptides and hormones were normal. Unequivocal evidence of a neuropathic lesion is provided by this patient; her disorder may be identified as the fifth type of hereditary sensory and autonomic neuropathy. The second patient had a congenital pansensory neuropathy and progressive retinitis pigmentosa. Whether the disorder is inherited and, if so, whether the retinitis pigmentosa results from the same or from a second genetic abnormality, is unclear. The third case has, in addition to what is usually seen in hereditary sensory and autonomic neuropathy, type II, an unusually severe kinaesthetic difficulty in oral food handling. The sural nerves of the second and third patients had fibre composition characteristic of hereditary sensory and autonomic neuropathy, type II, few or no myelinated fibres and reduced numbers of unmyelinated fibres.

Autonomic Nervous System Diseases↗

PubMed1983

Evaluation of skin vasomotor reflexes by using laser Doppler velocimetry.

We used a laser Doppler velocimeter for measurement of skin blood flow in 63 healthy control subjects and in patients with dysautonomias. We measured vasoconstrictor responses to inspiratory gasp, standing, Valsalva maneuver, and cold stimulus. An abnormal profile was defined in terms of the percentage of abnormal test results, the results of individual tests, and the alterations in the shape of the recorded response. These measurements of vasomotor function may permit the diagnosis of focal abnormalities of peripheral nerve sympathetic failure.

Adolescent↗

PubMed1981

The splanchnic autonomic outflow in amyloid neuropathy and Tangier disease.

The splanchnic outflow is important in the maintenance of postural normotension in humans. Pathology of outflow is usually associated with postural hypotension. Morphometric analyses were performed on the intermediolateral column neuron cell bodies at the T7 level in four cases of amyloid neuropathy and one case of Tangier disease. In amyloid neuropathy, postural hypotension is common; cell counts were reduced and ranged from 50 to 79% of control values. In Tangier disease, postural hypotension has not been reported; cell counts were normal.

Adult↗

PubMed1981

Midodrine. A new agent in the management of idiopathic orthostatic hypotension and Shy-Drager syndrome.

Five patients with idiopathic orthostatic hypotension, two of whom had central nervous system manifestations (Shy-Drager syndrome), were treated with midodrine, an investigational alpha-adrenergic agonist, in a dosage of 2.5 to 5 mg three times daily. Significant improvement was observed in the standing systolic and diastolic blood pressures at the end of 1 week of therapy in all patients and has been maintained for 10 to 15 months in all patients. No symptomatic side effects were noted. Supine systolic hypertension occurred in two patients and was treated with small doses of metoprolol.

Adult↗

PubMed1981

Orthostatic hypotension.

This article reviews the physiology and pathology of orthostatic blood pressure regulation. It describes the diverse clinical disorders of postural blood pressure adjustment, focusing attention on idiopathic orthostatic hypotension and the Shy-Drager syndrome, with emphasis on clinical aspects, pharmacology, and pathologic anatomy. Proposals are made for the diagnostic evaluation of patients with orthostatic hypotension and for steps to be taken in therapeutic management.

Adult↗