Search PubMed⌕ Search

Biomedical subjects

D C Taylor

Publications and source records attributed to D C Taylor.

At least 127 records · Page 7Linked to original sources
PubMed1988

Duplex ultrasound scanning in the diagnosis of renal artery stenosis: a prospective evaluation.

Since ultrasonic energy can be used to interrogate vessels at great depth, it is only natural that it should be applied to deeply placed arteries in the abdomen. Early studies suggested that high-grade stenoses of the renal artery could be detected by this approach as long as the peak systolic velocity in the renal artery was normalized by that measured in the abdominal aorta. A retrospective study comparing the peak velocity in the renal artery to that from the adjacent abdominal aorta (the renal aortic ratio) showed that if this value exceeded 3.5, it is likely to be associated with a greater than 60% diameter-reducing stenosis. To test this hypothesis, we used duplex scanning to prospectively evaluate 58 renal arteries in 29 patients in whom arteriograms were available. There were 39 renal arteries with 0% to 59% stenosis, 14 with 60% to 99% stenosis, and five occlusions by angiography. Renal duplex scanning accurately diagnosed 38 of 39, 11 of 14, and four of five of these, respectively, giving a sensitivity of 84%, a specificity of 97%, and a positive predictive value of 94% for the detection of a greater than 60% diameter-reducing stenosis. The overall agreement with angiography was 93%. These data show that renal duplex scanning can be used to diagnose renal artery stenosis in patients with hypertension or renal dysfunction, thus providing a rational basis for the selection of patients for angiography.

Adolescent↗
PubMed1987

An analysis of the responses of rat striatal neurones to scrotal skin temperature.

The responses of neurones in the caudate-putamen complex of anaesthetised rats to different scrotal skin temperatures were examined, together with the electroencephalogram (EEG). Caudate neuronal firing patterns did not change independently of rate, unlike the thermo-responsive cells of the hypothalamus previously reported. The scrotal skin temperature threshold for the caudate neuronal response corresponds precisely with the temperature which provokes desynchronisation of the EEG.

Action Potentials↗
PubMed1987

Assessment of gastric emptying using gamma scintigraphy.

Gamma scintigraphy was used to measure the gastric emptying rates of three test meals in human volunteers. Emptying rates were determined for solid and liquid materials alone, and for liquid in the presence of solid material. It was shown that the emptying of solids from the stomach was significantly slower than that of liquid, whether liquid alone or liquid in the presence of solid material. It was concluded from these results that, in the case of a solid test meal from which radio-label could be eluted, the free label would empty considerably faster than the remaining solid material. The emptying rate observed scintigraphically would not, therefore, be a true estimate of the solid emptying rate.

Contrast Media↗
PubMed1987

Temporal lobe epilepsy: origin and significance of simple and complex auras.

The aura experience of 88 patients with temporal lobe epilepsy was recorded, classified and analysed. Despite the great richness of the 215 experiences described, correlations with left or right brain, nature of lesion, age of onset, etc. were only apparent when a classification into three aura groups was used. "Simple primitive" auras as sole auras were more likely with early onset epilepsy, in lower IQ patients, in males, from the right temporal lobe, and with mesial temporal sclerosis. Exclusively "intellectual" auras were confined to a group of high IQ males. The number of aura experiences described per person correlated with Verbal IQ for males but not females, but also varied with side, sex, and nature of lesion. The results are discussed in terms of the necessary conditions for aura and their relevance and in relationship to the results of brain stimulation studies by Penfield and others.

Epilepsy, Temporal Lobe↗
PubMed1987

Predicting failure in polytetrafluoroethylene vascular access grafts for hemodialysis: a pilot study.

In order to determine if serial, noninvasive evaluation of polytetrafluoroethylene (PTFE) vascular access grafts could identify a subgroup of patients at risk for thrombosis, the authors studied flow characteristics, using duplex ultrasonic scanning, in 18 hemodialysis patients with forearm loop grafts. On average, five examinations were performed per patient over the 10-month study period. Seven episodes of thrombosis occurred in six patients. The mean Doppler flow in grafts that subsequently thrombosed was significantly lower than in those that did not (544 +/- 218 ml/min versus 843 +/- 391 ml/min, p less than 0.001). The interval from last examination to thrombosis ranged from 13 to 58 days. At a defined cut-off flow of 450 ml/min, this test yielded a sensitivity of 83% and a specificity of 75% for episodes of thrombosis occurring within 2 to 6 weeks. The authors conclude that episodes of thrombosis in PTFE arm loop grafts are usually preceded by significantly lower Doppler-measured flow than grafts that do not thrombose and that it may be possible, by this means, to identify grafts at risk.

Blood Vessel Prosthesis↗
PubMed1987

Aortic surgery and horseshoe kidney: a challenging surgical problem.

Horseshoe kidney is a rare abnormality that complicates aortic surgery. Three such cases are presented and the literature is reviewed. Although the diagnosis was not made preoperatively in any patient, all were managed safely. Two patients required preservation of abnormal renal arteries and one required division of the renal isthmus for exposure. Special attention is drawn to the need for lateral angiographic projections of this condition and to the intraoperative injection of indigo carmine dye to delineate the proper line of division of the renal isthmus.

Aged↗
PubMed1986

Alteration of the discharge pattern of rat diencephalic neurones with scrotal skin temperature.

Neuronal responses to different scrotal skin temperatures were examined in the hypothalamus of anaesthetised male rats. Mean firing rate and interspike intervals were calculated on-line by microcomputers. Two types of response were observed when the scrotal skin was warmed: an abrupt change in mean firing rate coupled with a change in firing pattern, or a change of pattern unaccompanied by any change in mean rate. These results suggest that hypothalamic cells can convey information independently of their mean firing rate.

Action Potentials↗
PubMed1986

Representation of the path of a non-disintegrating capsule in the gastrointestinal tract using external scintigraphy and computer graphics.

The intestinal transit rate of a single non-disintegrating object has been measured using gamma scintigraphy. Using computer graphics, a three-dimensional visualization of the data has been developed. The display enables viewing from any angle and should be of value in assessing the effect of variables on the transit of pharmaceuticals and other materials.

Capsules↗