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Biomedical subjects

M R Cross

Publications and source records attributed to M R Cross.

9 recordsLinked to original sources
PubMed1995

Serum fluoride concentration and urine osmolality after enflurane and sevoflurane anesthesia in male volunteers.

The purpose of this study was to measure the serum fluoride concentration after enflurane or sevoflurane anesthesia and to compare the effects of prolonged anesthesia with these drugs on renal concentrating function in male volunteers. The study was subdivided into three stages; an ascending dose study of 3.0 and 6.0 minimum alveolar anesthetic concentration (MAC) hours of sevoflurane alone, a 6.0-MAC-hour comparison of enflurane and sevoflurane, and a 9.0-MAC-hour comparison of enflurane and sevoflurane. Renal concentrating function was assessed by an 18-h period of fluid deprivation and the serum fluoride concentration was measured at intervals until 60 h postanesthesia. The maximum serum fluoride concentration was greater in the volunteers exposed to sevoflurane and reached a peak in the 9-MAC-hour sevoflurane group of 36.6 microM (SD 4.3) compared with 27.5 microM (SD 2.6) in the 9-MAC-hour enflurane group. However, the rapid decrease in the serum fluoride concentration after sevoflurane was such that there was no difference between the areas under the fluoride concentration-time curves. There were no significant differences between the median maximum urine osmolalities after enflurane or sevoflurane anesthesia. Prolonged anesthesia with enflurane or sevoflurane is not associated with impaired renal concentrating function despite an increase in the serum fluoride concentration.

Adolescent↗
PubMed1988

Ocular fundus lesions in divers.

Retinal fluorescein angiography was used to examine the ocular fundi of 84 divers. The retinal capillary density at the fovea was low and microaneurysms and small areas of capillary nonperfusion were seen. The divers had significantly more abnormalities of the retinal pigment epithelium than a comparison group of non-divers. Furthermore, the prevalence of fundus abnormality was related to length of diving history. All observed changes were consistent with the obstruction of the retinal and choroidal circulations. Such obstruction could be due either to intravascular bubble formation during decompression, or to altered behaviour of blood constituents and blood vessels in hyperbaric conditions.

Adolescent↗
PubMed1980

Mucinous cystadenoma of the pancreas. Endoscopy as an aid to diagnosis.

Pancreatitis and pancreatic insufficiency have not previously been associated with mucinous cystadenoma of the pancreas. This report describes a patient with a long history of chronic pancreatitis whose course was complicated by obstructive jaundice and cholangitis and pancreatic insufficiency. Endoscopy with retrograde cholangiopancreatography provided the correct diagnosis, and the findings are described.

Aged↗
PubMed1979

An effective conscious animal model of atrial fibrillation.

In 11 fully conscious dogs with chronically implanted spicardial electrodes, 50 Hz sine-wave electrical stimulation of the left atrium reliably and repeatedly produced an arrhythmia which was indistinguishable from atrial fibrillation in terms of its ECG appearance, the statistical properties of the ventricular response and responses to a number of pharmacological agents. In five of the 11 preparations this arrhythmia consistently persisted for periods in excess of 10 min following the cessation of stimulation, indicating an intrinsic cardiac basis for the arrhythmia and suggesting that it is true atrial fibrillation. A close correlation between the ventricular response to this arrhythmia and the degree of atrioventricular conductivity, together with the observation that dramatic changes can occur in ventricular responses without corresponding changes in atrial activity, suggest that the ventricular response is mainly a function of the atrio-ventricular conducting system. The experimental model described is useful for the study of both short and long term drug action no atrial fibrillation and for the evaluation of methods used therapeutically in attempts to terminate episodes of paroxysmal atrial fibrillation.

Animals↗