Search PubMed⌕ Search

Biomedical subjects

D H Edwards

Publications and source records attributed to D H Edwards.

87 records · Page 5Linked to original sources
PubMed1977

The spinal abnormalities in thalidomide embryopathy.

In 1968 a study was made of the spinal changes in 32 children with multiple congenital abnormalities due to thalidomide. Twenty-eight of these children have been traced and their spinal changes reviewed. Only four patients had normal spines on radiography. In eight children, scoliosis was present and had progressed though it was still of mild degree. Disc and end-plate abnormalities were seen in 14 children, and in some appeared to be progressive, leading to intervertebral fusion.

Abnormalities, Drug-Induced↗
PubMed1976

Cement burns.

Four cases are presented of men who sustained burns after contact with premixed concrete. The pathogenesis of the condition is discussed.

Adult↗
PubMed1976

The value of low dosage heparin for the prophylaxis of thromboembolism in patients with transcervical and intertrochanteric femoral fractures.

One hundred and ten female patients, over the age of 60, with intertrochanteric or transcervical fractures were included in a controlled, randomized, clinical trial investigating the value of low dosage heparin in the prophylaxis of deep vein thrombosis. There were 50 completed pairs. Eight (16 per cent) deep vein thromboses occurred in the heparinized group compared with 23 (46 per cent) deep vein thromboses in the control group. The incidence of pulmonary embolism was also reduced. The diagnosis of deep vein thrombosis was made on clinical grounds, supplemented by phlebography and autopsy. There was no difference in the wound hematoma or infection rate. The heparin was commenced on admission to hospital and it is suggested that in this group of patients low dosage heparin prophylaxis should start on admission and not wait until surgery.

Aged↗
PubMed1975

Prophylaxis with dextran 70 against thrombosis in patients with fractures of the upper end of the femur.

A trial was undertaken to assess the effect of dextran 70 (Macrodex) in prophylaxis against thrombosis in womem over 65 years with fractures of the upper end of the femur. The dosage used was 500 ml at operation and 500 ml on the first postoperative day. At this dosage given at this time there was no difference in the overall incidence of clinically diagnosed deep venous thrombosis in the group of patients given dextran 70 compared with the control group. There was a tendency for thrombosis to occur earlier in the control group. The mortality rates at 3 weeks and even at 6 months were less in the treated group than in the control series.

Clinical Trials as Topic↗
PubMed1975

The use of seat belts by motor car occupants involved in road traffic accidents.

Two hundred and forty-four motor car occupants involved in road traffic accidents, who sustained injuries sufficiently severe to require admission to hospital, have been investigated in order to assess the value of seat belts. The results indicated that the use of seat belts significantly reduced the mortality and the number of severe, multiple and facial injuries.

Accidents, Traffic↗
PubMedDate not supplied

Peripheral laser angioplasty with pulsed dye laser and ball-tipped optical fibres.

Laser angioplasty with the pulsed dye laser and integral ball-tipped optical fibres was used for primary treatment of occlusive femoropopliteal vascular disease in 26 limbs of 24 patients, all of whom warranted operative intervention. 19 had "critical ischaemia", 8 had pedal ulceration, and 4 had distal gangrene. The delivery device consisted of the laser fibre loaded retrogradely into a standard 6 mm balloon angioplasty catheter, and was introduced through a common femoral artery cutdown in an attempt to recanalise femoropopliteal occlusions of a mean length of 21 cm (range 3-49). Angiographic recanalisation was achieved with a mean energy of 250 J (range 38-727 J) in 23 of the 26 limbs; in each case the channel created by the laser fibre was augmented by balloon angioplasty. Technical failure occurred in 3 patients, due to wall dissection, persistent side-branch entry, and incomplete lesion penetration, respectively. Acute occlusion within 48 h occurred in 2 diabetic patients with very poor run-off and distal gangrene, and early failure occurred in another patient due to inadequate balloon dilatation. 1 patient with segmental tibial disease below a technically successful recanalisation did not show clinical improvement. Several patients had coexisting coronary artery disease, 3 of whom died of myocardial infarction--all with patent femoropopliteal vessels. In the 21 survivors, 14 vessels remained patent at a median of 7 months' follow-up.

Aged↗
PubMedDate not supplied

The nature of endothelium-derived vascular relaxant factor.

The existence of endothelium-derived vascular relaxant factor (EDRF) was postulated by Furchgott and colleagues when they observed that acetylcholine paradoxically relaxed preconstricted aortic strip preparations by an endothelium-dependent mechanism. This phenomenon has since been demonstrated in different blood vessels and mammalian species and it can be elicited by several other agents. EDRF has been thought to be a humoral agent, a lipoxygenase derivative and possibly a free radical. In the study reported here, by using aortic preparations from the rabbit, alone and in cascade experiments with isolated perfused coronary preparations, we demonstrate definitively that EDRF is a humoral agent. It is released from unstimulated aortic preparations containing endothelium, its release can be stimulated for prolonged periods by acetylcholine, and it is not a lipoxygenase derivative or free radical but an unstable compound with a carbonyl group at or near its active site.

Acetylcholine↗
PubMedDate not supplied

EDRF coordinates the behaviour of vascular resistance vessels.

Constriction of vascular smooth muscle in response to the stimulus of raised intravascular pressure--the myogenic response--represents a positive feedback mechanism which, if unopposed, could theoretically lead to instability in the intact circulation. Dilation in response to increased intraluminal flow would provide an opposing feedback mechanism which could confer overall stability. Flow-dependent dilation in conduit vessels is mediated by endothelium-derived relaxing factor (EDRF), but the relationship between flow and EDRF activity has not been studied in resistance vessels in situ. We here demonstrate that EDRF can coordinate the aggregate hydrodynamic properties of an intact network. Under control conditions, EDRF maintains a fourth-power relationship between diameter and flow so that the pressure gradient in each vessel asymptotically approaches a constant value at high flow rates. Basal EDRF release may also maintain a similar spatial distribution of flow at different flow rates, even under conditions of moderate pharmacological constriction.

Animals↗
PubMedDate not supplied

Mechanisms underlying chaotic vasomotion in isolated resistance arteries: roles of calcium and EDRF.

Nonlinear mathematical techniques now make it possible to quantify the complexity of an irregular time series through calculation of a parameter known as fractal dimension. In the present study, we use such an analysis to provide evidence that histamine-induced pressure oscillations in an isolated rabbit ear resistance artery are generated by deterministic rather than stochastic mechanisms, and that a minimum of 3 independent control variables is necessary to account for the complexity of the dynamics of these oscillations. The fractal dimension of the responses was independent both of the concentration of histamine used to induce rhythmic behavior, and the level of activity of the endogenous nitrovasodilator, EDRF. While both superficially influenced the form of the oscillations, it follows that neither are key control variables involved in their genesis. Nonlinear analysis of data obtained in the presence of NG-nitro-L-arginine methyl ester (L-NAME), which blocks EDRF synthesis, provided insights into the intrinsic smooth muscle control mechanisms responsible for generating rhythmic activity. The oscillations exhibited distinct "fast" and "slow" components (periods of 5-20 secs and 1-5 min. respectively). The former involved ion movements at the cell membrane and was inhibited by low [Ca2+]o, verapamil (which blocks voltage-dependent Ca2+ influx) and tetraethylammonium (which blocks Ca(2+)-activated outward K+ channels), whereas the latter involved Ca(2+)-induced Ca2+ release from intracellular stores and was inhibited by ryanodine. All such interventions decreased the overall fractal dimension of the responses to a value < 2, thus removing one degree of complexity (and hence control variable) from the dynamics. We conclude that the nonlinear interaction between a fast membrane oscillator and a slow intracellular oscillator generates chaos in vascular smooth muscle and that exogenous constrictor agonists and EDRF may be regarded as permissive and modulatory influences, respectively.

Animals↗