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Biomedical subjects

D Doyle

Publications and source records attributed to D Doyle.

228 records · Page 13Linked to original sources
PubMedDate not supplied

Tolerance and cross-tolerance to the effects of amphetamine, methamphetamine and fenfluramine on milk consumption in the rat.

It has been reported that rats develop tolerance to the milk intake suppressant effects of d-amphetamine, d-methamphetamine, and d, l-fenfluramine. However, it has been hypothesized that the mechanism of action of fenfluramine is different from that of the other two drugs. In the present experiment, rats were given one of these 3 phenylethylamine derivatives each day until tolerance developed to the suppression of milk intake. A second of these drug s was then substituted and milk intake measured. There was cross-tolerance to the drug-induced suppression between d-amphetamine and d-methamphetamine, but not between d-amphetamine and d,l-fenfluramine. The lack of cross tolerance suggests a different mechanism of action for these drugs.

Animals↗
PubMedDate not supplied

The contusion index: a reappraisal in human and experimental non-missile head injury.

A previously described method of quantifying cerebral contusions in man (the contusion index) caused by non-missile head injury has been modified and applied to a larger series of cases, and used to assess contusions in experimental head injuries. The initial findings in man have been confirmed, viz. that contusions are most severe in the frontal and temporal lobes; that contusions may be entirely absent in a patient dying as a result of a head injury; that there is no correlation between the severity of contusions and the nature of the injury; that the concept of contrecoup must continue to be questioned; that contusions are more severe in patients who have a fracture of the skull in comparison to those who do not; that contusions are more severe in patients who do not experience a lucid interval than in those who do; and that contusions are less severe in patients with diffuse axonal injury than in those who do not have diffuse axonal injury. The distribution of contusions in subhuman primates is similar to that seen in man, and they occur more frequently with short duration than with long duration acceleration.

Adolescent↗
PubMedDate not supplied

Brain damage in non-missile head injury secondary to high intracranial pressure.

A comprehensive neuropathological analysis was undertaken on 434 patients who died as a result of a non-missile head injury in order to determine the frequency and extent of brain damage secondary to high intracranial pressure (ICP) in head injury. Using the criterion of pressure necrosis in the parahippocampal gyrus as evidence of high ICP due to a supratentorial expanding lesion, it was established that the ICP had been high in 324 cases. In 42 of these there was no other brain damage attributable to a high ICP. There was evidence of secondary brain stem damage in 221 cases and in 44 of these the damage could be seen only microscopically. In 54 cases there was a contralateral peduncular lesion. Other abnormalities were infarction in the territories of various arteries and in the anterior lobe of the pituitary. There was a supracallosal hernia in 80 cases and haemorrhage in the oculomotor nerves in 48 cases. These results further emphasise the frequency and range of brain damage due to secondary vascular factors brought about by high ICP in a patient who has sustained a head injury.

Adolescent↗
PubMedDate not supplied

Transient left ventricular pulsus alternans in severe aortic valve disease.

A 56-year-old man presented with severe aortic valve disease. Pulsus alternans was recorded in the left ventricle, apparently provoked by catheter placement through a stenotic aortic valve. This case illustrates that studies on left ventricular performance in severe aortic stenosis should be done with a transseptal catheter.

Aortic Valve Stenosis↗
PubMedDate not supplied

Perioperative coronary spasm and right ventricular ischemia.

Perioperative coronary spasm after coronary bypass surgery is increasingly recognized as a possible cause of circulatory collapse. Most of the reported cases involved the right coronary artery (RCA). A case where transient right coronary spasm provoked right ventricular ischemia and collapse is described.

Adult↗
PubMedDate not supplied

Fatal non-missile head injury: a cohort study of patients with and without an intracranial hematoma.

Brain damage in fatal non-missile head injury is outlined in 100 cases with and in 100 cases without an intracranial hematoma. The patients with intracranial hematomas were significantly older, and had a higher incidence of lucid interval and of unilateral diffuse brain swelling but a lower incidence of ischemic lesions in the cerebral cortex and of bilateral diffuse brain swelling than the patients with no hematoma. Cases with unilateral hematomas and cases with unilateral diffuse brain swelling had significantly more severe ipsilateral cerebral contusions.

Adolescent↗
PubMedDate not supplied

Surgical treatment of diabetic foot ulcers: a review of forty-eight cases.

Large vessel disease, small vessel disease, and neuropathy leave the diabetic foot especially vulnerable to ulceration. The degree of vascular impairment of diabetic feet can vary, and such, patients with ulcers can be separated into ischemic and nonischemic groups. The degree of ischemia, and not necessarily the extent of the lesion, is the most significant factor in evaluating the potential outcome of treatment. Forty-eight cases of diabetic ulceration treated with local surgical intervention in an effort to avoid higher amputation were classified as ischemic and nonischemic, based on Doppler studies and physical examination. The success rate in the ischemic group was 25%. The success rate of the nonischemic group was 83%. It is concluded that local surgical management of diabetic ulceration can be a successful alternative to radical amputation in the diabetic patient, especially when adequate blood flow can be verified. Various surgical and nonsurgical approaches to all grades of diabetic feet are also discussed.

Arteriosclerosis↗