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Biomedical subjects

R C Kester

Publications and source records attributed to R C Kester.

At least 109 records · Page 6Linked to original sources
PubMed1982

Radionuclide and contrast venography following caval interruption by the Mobin-Uddin umbrella filter.

Either radionuclide or contrast venography, or both, were performed in nine patients 2 months to 4 years after insertion of Mobin-Uddin caval umbrella filter for prevention of recurrent pulmonary embolism. In six patients the cava was occluded, and three major groups of collaterals were observed (central, intermediate and superficial). Large gonadal veins, which may predispose to recurrent embolism, were seen in two cases. Radionuclide venography gave a clear indication of caval patency or occlusion, and distinguished central from superficial collaterals. Identification of specific gonadal veins required contrast femoral or iliac venography.

Collateral Circulation↗
PubMed1982

Peroperative cephradine concentrations in the gall bladder wall and bile.

Cephradine levels were assayed in serum, gall bladder wall and bile sampled from the gall bladder and common bile duct in 24 patients undergoing elective cholecystectomy. Cephradine was administered either as 1 g given intravenously at the time of anaesthetic induction, or as three 6-hourly doses of 0.5 g taken orally during the pre-operation day followed by 1 g intramuscularly with the premedication. Adequate antibacterial levels of cephradine were achieved in all serum samples, 8 of 9 samples of choledochal bile, 6 of 12 samples of cholecystic bile and all 12 samples of gall bladder wall in the group receiving a single intravenous dose, compared to only 4 of 12 serum samples, 6 of 11 choledochal bile samples, 6 of 10 cholecystic bile samples, and only 3 of 12 samples of gall bladder wall in the group receiving oral cephradine. Therefore, cephradine given as a 1 g bolus intravenously with anaesthetic induction provides satisfactory concentrations for antibacterial prophylaxis during gall bladder surgery but a regimen of oral and intramuscular dosage was found to be unsatisfactory.

Adult↗
PubMed1981

Arterial graft maturation: the duration of thrombotic activity in Dacron aortobifemoral grafts measured by platelet and fibrinogen kinetics.

Dacron is thrombogenic, hence small arterial grafts of this material frequently thrombose in the period prior to graft maturation. Anti-thrombotic therapy may therefore be indicated to preserve patency during this risk period. To evaluate the thrombogencity of immature Dacron grafts, platelet and fibrinogen kinetics using 51Cr and 125I respectively were measured before operation and at 3, 6 and 9 months in 10 patients following aortobifemoral bypass and in 6 age-matched volunteers. Platelet survival was reduced from 8.8 +/- 0.2 d before surgery to 7.4 +/- 0.24 d at 3 months. This was accompanied by an increase in platelet turnover from 39 +/- 2.4 X 10(9)l-1d-1 to 46.9 +/- 2.9 X 10(9)l-1d-1. Fibrinogen t1/2 fell from 3.72 +/- 0.13 d preoperatively to 3.36 +/- 0.11 d at 3 months, while fibrinogen fractional catabolic rate rose from 0.27 +/- 0.014 to 0.34 +/- 0.014. These changes were all significant (P less than 0.01). Fibrinogen consumption had returned to normal by 6 months following surgery but platelet kinetics only equated to preoperative levels at 9 months. We suggest that Dacron grafts are thrombogenically active for about 9 months. When anti-thrombotic therapy is indicated it should be continued throughout this period.

Aged↗
PubMed1980

The complications of arteriovenous grafts for vascular access.

An analysis has been made of the complications occurring in 86 arteriovenous grafts performed for vascular access over a 5-year period ending in July 1979. Synthetic grafts provide significantly more complication-free dialyses than do biological grafts. They are less susceptible to sepsis and aneurysm formation and, when thrombosis does supervene, synthetic grafts can be retrieved than biological grafts. Dacron velour in particular appears to have a low primary and secondary failure rate compared with other types of graft. Grafts implanted in the straight configuration have lower thrombosis rates than looped grafts. While the forearm remains the site of choice for the insertion of an arteriovenous graft, equally good results may be obtained with a graft interposed between the femoral artery and vein.

Adolescent↗
PubMed1980

Plasma phosphate and red cell 2,3-diphosphoglycerate following abdominal surgery.

Changes in plasma phosphate have been serially examined in 20 patients undergoing uncomplicated abdominal surgery. These studies confirm previous reports that a fall in plasma phosphate occurs in the postoperative period, but this does not appear to be metabolically deleterious to the patient since it is not accompanied by a significant concomitant fall in red cell 2,3-DPG. These investigations form a basis for studies in complicated patients and serve to refute the suggestion that phosphate supplements should be added to all routine postoperative infusions.

Abdomen↗
PubMed1980

High density lipoproteins and exercise.

High density lipoprotein (HDL) and total cholesterol (TC) levels have been measured and their ratio compared in four groups of subjects - those with vascular disease, controls, middle-aged "keep-fit" enthusiasts and young physical education students. Each group has also been subjected to analysis of risk factors known for atherosclerosis. The HDL level was significantly raised in the Athletic and Exercise groups even though the latter were more overweight and had the highest total cholesterol level. This would appear to indicate that exercise may exert its protective effect against atherosclerosis, at least in part, by elevating the HDL level above a certain critical level. The HDL/TC ratio was significantly lower in the Vascular group and we would advocate that any ratio less than 20% is highly suspicious of atherosclerosis. We suggest that both the HDL level and HDL/TC ratio should be viewed together as reflecting the risk of atherosclerosis.

Blood Pressure↗
PubMed1980

Tissue levels of cephradine in ischaemic limbs following a single intravenous injection.

A single dose of 2g cephradine was administered intravenously at the time of anaesthetic induction to 20 patients with occlusive arterial disease. Concentrations of cephradine were measured in serum, subcutaneous fat from the groins of 10 patients underdoing arterial reconstruction and in the subcutaneous fat and skeletal muscle of 10 legs amputated for severe arterial ischaemia. Concentrations of cephradine were adequate for antibacterial prophylaxis at the time of operation in all serum samples, 9 out of 10 samples of subcutaneous fat from reconstruction cases, all muscle and 8 of 10 fat samples from the level of section of amputated limbs, and in 8 of 10 muscle and fat samples from the distal parts of amputated limbs. These results confirm that a single intravenous dose of 2 g cephradine given with anaesthetic provides adequate serum and tissue concentrations for antibacterial prophylaxis during vascular surgery.

Aged↗
PubMed1980

Gravimetric plethysmography for measurement of blood flow in the leg.

The gravimetric plethysmograph measures blood flow in the limb in terms of the increase in weight which follows temporary venous occlusion. Following validation of the device, blood flow in the leg was evaluated in normal subjects and in patients with intermittent claudication. Measurement of the immediate hyperaemic response to a three-minute period of arterial occlusion proved to be very reproducible in patients with occlusive arterial disease of the legs.

Adult↗
PubMed1980

Antithrombotic therapy for vascular prosthesis: an experimental model testing platelet inhibitory drugs.

Although Dacron vascular grafts are widely used, they are thrombogenic and rapid blood flow maintains patency. When blood flow is suboptimal, antithrombotic therapy may prevent early occlusion. We evaluated the effect of three platelet inhibitory drugs: acetylsalicylic acid (ASA), dipyridamole (DPM), sulphinpyrazone (SPZ), and a combination of ASA plus DPM on platelet adherence to woven Dacron in an artificial circulation. Heparinized blood from 18 volunteers was divided equally for test and control circuits, and to the test each drug was added in therapeutic concentration. The experiment was repeated ex vivo using blood donated by six volunteers after each had taken, separately for 1 week: (1) no drug; (2) ASA, 300 mg, three times a day; (3) DPM, 100 mg, four times a day; (4) SPZ, 200 mg, four times a day; (5) ASA, 300 mg, plus DPM, 75 mg, combined, three times a day. Platelet count, adhesion and aggregation were measured during the 60-minute perfusion, and scanning electron miscroscopy of the graft's luminal surface was performed. ASA was the most effective single agent, significantly impairing platelet function and reducing consumption of platelets by the graft. DPM reduced platelet adherence only in the ex vivo experiment, and its addition to ASA imparted no further influence. Sulphinpyrazone had little effect in either experiment. Antithrombotic therapy with ASA and DPM requires clinical evaluation.

Aspirin↗
PubMed1979

Arteriovenous grafts for vascular access in haemodialysis.

The outcome of 68 arteriovenous grafts placed in 46 patients requiring haemodialysis was studied over a period of 3.5 years. The biological grafts included autogenous saphenous vein, modified bovine carotid artery and human umbilical cord vein allograft, whereas the synthetic grafts comprised Sparks Dacron mandril, expanded reinforced polytetrafluoroethylene and knitted Dacron velour. These subcutaneous grafts were arranged as looped or straight configurations in the forearm or thigh. Of 59 grafts evaluated in patients with end-stage renal failure, only 48 per cent of the forearm grafts performed well, compared with 85 per cent of the thigh grafts. Although only 38 per cent of the looped grafts were successful, 78 per cent of the straight grafts functioned satisfactorily. Synthetic grafts suffered less serious complications than the commercial biological grafts.

Adolescent↗
PubMed1979

The penetrability of cephazolin into the subcutaneous fat and skeletal muscle of ischaemic lower limbs with atherosclerotic disease.

Seventeen patients with atherosclerotic disease, who were undergoing arterial reconstruction or amputation of the lower limb, had 2 g cephazolin injected per-operatively in two equal doses by intramuscular and intravenous routes. Samples of subcutaneous fat and skeletal muscle from the ischaemic leg, and serum were collected during the operation for assay of cephazolin content. The mean cephazolin levels in the serum, skeletal muscle and subcutaneous fat were found to be well above the minimum inhibitory concentrations required for most important Gram-positive and Gram-negative pathogens.

Adipose Tissue↗
PubMed1979

Evaluation of tissue levels of cefamandole in severely ischaemic lower limbs using two regimens of dosage.

Cefamandole levels were measured in peripheral blood, and in skeletal muscle and subcutaneous fat samples taken from 20 patients during amputation of the leg for severe ischemia. Tissue samples were taken from both proximal and distal levels in the amputated limb. Cefamandole was administered as either a 2 g intravenous bolus given with induction of anaesthesia, or a combination of 1 g intramuscularly with the premedication plus 1 g intravenously with anaesthetic induction. Levels of cefamandole in serum and proximal muscle and fat samples were well above the minimum inhibitory concentrations required for most Gram-positive and Gram-negative organisms. Cefamandole levels in more distal samples were somewhat lower but still achieved therapeutic levels in most cases. Higher tissue levels of cefamandole were achieved when 2 g were given intravenously as a bolus.

Adipose Tissue↗