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Biomedical subjects

R A Sherlock

Publications and source records attributed to R A Sherlock.

6 recordsLinked to original sources
PubMed1997

Carotid endarterectomy in the presence of a persistent hypoglossal artery: case report.

OBJECTIVE AND IMPORTANCE: A persistent hypoglossal artery, one of the embryonic carotid-basilar anastomoses that can fail to regress in the embryo and can be observed past birth, is one of the only congenital anatomic variations of the internal carotid artery (ICA) that can complicate the performance of carotid endarterectomy. When associated with atherosclerotic carotid artery disease, the recognition and intraoperative management of a persistent hypoglossal artery is important. CLINICAL PRESENTATION: A 72-year-old man presented with a symptom of transient right hemisphere ischemia, and although ultrasonography indicated a right ICA stenosis (and no other abnormality), angiography also demonstrated that the atherosclerotic plaque extended into the origin of a large right persistent hypoglossal artery arising 1.5 cm from the origin of the ICA. In this patient, the persistent hypoglossal artery was the only arterial supply to the basilar artery. INTERVENTION: The patient underwent a right ICA endarterectomy, and intraoperative angiography was necessary to ensure that the persistent hypoglossal artery was the vessel shunted during the arterial repair. CONCLUSION: Recognition of the primitive carotid-basilar anastomoses is important to surgeons who perform carotid endarterectomy and is not possible with ultrasonography alone. Intraoperative angiography enables the surgeon to accurately catheterize a persistent hypoglossal artery with a carotid shunt.

Basilar Artery↗
PubMed1994

Mammary epithelial cell tight junction integrity and mammary blood flow during an extended milking interval in goats.

The timing and relation of changes in mammary epithelial cell tight junction integrity and mammary blood flow during a 36-h milking interval were studied in six lactating Saanen goats. An increase in lactose concentration in plasma, a decrease in transepithelial potential difference, and changes in ionic milk composition were used to indicate tight junction patency. After 36 h of milk accumulation, mammary tight junctions had become disrupted. Further analyses indicated that this disruption began after 21 h of milk accumulation and that mammary blood flow also started to decline after 21 h. The time when both events occurred was not significantly different from the time when milk secretion began to decline (19 h). Moreover, positive but nonsignificant correlations existed between these events. Mammary tight junctions became disrupted when milk secretion declined, suggesting that impairment of mammary tight junction integrity is associated with decreased milk secretion during an extended milking interval. The decline in mammary blood flow may be the result of a negative feedback response to a reduced demand for metabolites, which is due to a reduced rate of milk secretion.

Animals↗
PubMed1993

Aneurysmal cyst, bone type, primary in an artery.

An aneurysmal bone cyst-like reaction involving the left common carotid artery bifurcation in an otherwise healthy 7-year-old boy is described. The patient presented with a 6-week history of an enlarging pulsatile neck mass. The mass was excised with connection of arteries on either side with a saphenous vein graft. There were no associated intracranial arterial aneurysms or associated skeletal lesions. A history of trauma could not be elicited. To the best of our knowledge this is the first report of an aneurysmal cyst, bone type, involving a large blood vessel.

Aneurysm↗
PubMed1986

Determination of transmembrane currents from external potential measurements by the method of regularization.

A novel non-invasive technique for measuring the transmembrane currents during action potential depolarizations of stalk segments of the giant unicellular alga Acetabularia mediterranea is described. This involves measurement of spatial samples of the time-dependent potential in the external medium (sea water) and an inverse transformation to give the current distribution at the cell surface. A detailed description of the method of regularization needed to handle this ill-conditioned inversion problem is presented in this paper, along with the results of test experiments to demonstrate its validity. An example of its application to the data recorded from an actual cell is also given.

Acetabularia↗