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Biomedical subjects

P Gaskell

Publications and source records attributed to P Gaskell.

At least 19 recordsLinked to original sources
PubMed1991

Genetic linkage analysis of nerve growth factor (beta) in familial Alzheimer's disease.

Recent studies have not shown linkage of late-onset (mean age, greater than 60 years) familial Alzheimer's disease (FAD) to the chromosome 21 locus reported linked to early-onset FAD. Beta nerve growth factor (beta-NGF) has been considered a candidate gene in the pathogenesis and therapy of FAD, based on its localization in the cortex and hippocampus and its ability to enhance the growth and survival of cholinergic neurons. A 1.5-kb fragment of the beta-NGF gene was used to detect a BglII restriction fragment length polymorphism, which was then used for linkage analysis. A total of 30 families (27 late onset) with 147 affected members were studied. Close linkage (theta less than or equal to 0.03, z less than or equal to -2.00) of late-onset FAD with beta-NGF was excluded. Two apparent obligate crossovers between affected members were detected in different autopsy-confirmed families. Based on these results, beta-NGF is not the gene responsible for late-onset FAD in the families analyzed.

Aged↗
PubMed1978

The effect of a mechanical venous pump on the circulation of the feet in the presence of arterial obstruction.

A boot of single layer, flexible vinyl sheeting and a pneumatic cuff encircling its top at the ankle, each independently inflatable, constitute a mechanical venous pump. Inflation of the cuff to the desired boot pressure is followed immediately by inflation of the boot from a reservoir with higher available pressure than that in the cuff. When the boot pressure reaches cuff pressure, the excess air escapes from the boot under the cuff. A low venous pressure at the foot could be maintained by compressing the foot for 2 seconds every 15 seconds with a pressure which is 10 millimeters of mercury above initial venous pressure. In seated patients with arterial obstruction whose supine ankle blood pressure was 60 milimeters of mercury or less, the rate of blood flow in the skin of the forefoot was increased by 104.1 +/- 43.7 per cent S.E.M., p less than 0.05, during venous pumping. In these patients, a change in posture alone from supine to sitting increased the rate of blood flow by 81.7 +/- 19.47 per cent, p less than 0.002. The combined effect of the erect posture and venous pumping was an increase of 185.7 +/- 49.63 per cent, p less than 0.01. Rest pain was relieved by the combined effect.

Adult↗
PubMed1976

Critical opening pressure and reactivity of tail vessels in conscious hypertensive rats.

The possible role of increased vascular reactivity in the mechanism of experimental hypertension was studied by measurements of the critical opening pressure (COP) of tail vessels in conscious rats. In hypertension induced by administration of desoxycorticosterone acetate (DOCA) and replacement of the drinking water by 1% NaCl solution (DOCA-NaCl hypertension), and in one-kidney Goldblatt renovascular hypertension, the raised level of blood pressure was associated with an increased COP of the tail vessels when measured both before and after ganglionic blockade. In rats treated with either DOCA alone or 1% NaCl alone there was no significant increase in systolic blood pressure (SBP) or COP relative to the corresponding controls. In all four experimental series intravenous infusion of angiotensin or norepinephrine in conscious ganglion-blocked rats produced dose-dependent increases in SBP and COP. In DOCA-NaCl hypertensive rats but not in renovascular hypertensives, nor in rats treated with DOCA alone or 1% NaCl alone, the increase in COP for a given increment in dose of angiotensin or norepinephrine was significantly greater than in the control rats. It is concluded that in DOCA-NaCl hypertension there is a true increase in the reactivity of the smooth muscle of the resistance vessels to angiotensin and norepinephrine. In renovascular hypertension this is not the case and other factors must therefore be involved in causing the increased blood pressure and COP.

Angiotensin II↗
PubMed1975

Assessment of arterial obstruction in vessels supplying the fingers by measurement of local blood pressures and the skin temperature response test--correlation with angiographic evidence.

The systolic blood pressure measured in the fingers and wrists by the spectroscopic method and in the arm by auscultation were correlated with angiographic evidence of organic arterial obstruction in 29 patients. The pressures also were measured in 14 normal people. Results in the normal people suggest that a difference of more than 15 mm. Hg between the pressure measured simultaneously in corresponding fingers (or any two or more fingers), an absolute digital pressure less than 70 mm. Hg, or wrist-to-digit gradient of more than 30 mm. Hg, all in the warm subject and warmed hand, indicated the presence of organic obstruction. These criteria indicated the presence of organic arterial obstructive disease in 25 of 26 hands with definite angiographic evidence of it. The pressures were "normal" in five hands with no angiographic evidence of organic arterial obstruction. The digital skin temperature response to indirect heating was much less successful than were pressure measurements in identifying fingers with organic arterial obstructive disease.

Adolescent↗
PubMed1971

The importance of penile blood pressure in cases of impotence.

It appears that the normal penile systolic blood pressure, as measured by a spectroscopic method, is equal to or greater than the calculated brachial mean blood pressure. A pressure definitely lower than this in impotent patients indicates obstruction to blood flow in the main vessels supplying the penis. On this basis, obstruction to blood flow was identified as a cause of impotence in patients with little other evidence of peripheral vascular disease.

Adult↗
PubMed1971

The erect posture as an aid to the circulation in the feet in the presence of arterial obstruction.

When the main artery in the lower limb is occluded and narrow collateral vessels by-passing the obstruction offer the limiting resistance to blood flow, the increase in arterial pressure at the ankle on assuming the erect posture is greater than would be predicted by consideration of the hydrostatic factors. In seven patients with femoral artery occlusion the pressure at the ankle was greater than expected in all and on the average by 8.0 mm. Hg+/-1.5 S.E. when sitting, (P<0.01) and in the four patients tested, by 12.4 mm. Hg+/-0.5 S.E. when standing (P<0.01). Rate of blood flow in subdermal tissue of the forefoot estimated by xenon-133 clearance was an average of 21% less when sitting than when supine in five limbs of four normal subjects while in five limbs with occlusion or severe stenosis of the superficial femoral artery the rate of flow was an average of 44% greater.

Adult↗