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Biomedical subjects

W H Harris

Publications and source records attributed to W H Harris.

At least 343 records · Page 19Linked to original sources
PubMed1978

The relationship of intravascular coagulation and fibrinolysis to venous thrombosis following total hip replacement.

Soluble fibrin complexes, fibrin degradation products, and anti-thrombin III levels were determined in the plasma of 20 patients undergoing elective total hip replacement. The presence of deep venous thrombophlebitis was determined by venography at the end of the first postoperative week. Patients who developed thrombosis exhibited impairment of fibrinolysis as de-Patients who developed thrombosis exhibited impairment of fibrinolysis as detected levels of anti-thrombin III and soluble fibrin complexes were not useful in indicating the presence of deep venous thrombosis. However, the preoperative level of soluble fibrin complexes closely correlated with the subsequent development of thrombosis. Elevated soluble fibrin complexes appear to identify a group of patients with activated coagulation systems who are prone to develop thrombosis during total hip replacement.

Antithrombin III↗
PubMed1977

Aspirin prophylaxis of venous thromboembolism after total hip replacement.

We assessed aspirin prophylaxis against venous thromboembolism in a prospective, controlled, double-blind study of patients over 40 years of age, who had undergone total hip replacement. Radiographic phlebography was the diagnostic end point. Thromboembolism developed in 11 of 44 patients receiving aspirin, as compared to 23 of 51 receiving the placebo (P less than 0.03). Unexpectedly, this protection was limited to men. In four of 23 men on aspirin thrombi developed, as compared to 14 of 25 receiving placebo (P less than 0.01). Corresponding figures for women were seven of 21 versus nine of 26. Review of a similar group of patients receiving aspirin revealed significantly greater protection (P less than 0.03) in men (three of 15) than in women (15 of 27). These data establish statistically significant prophylaxis in men over the age of 40 by 600 mg of aspirin given twice daily. The absence of a protective effect in women remains unexplained.

Adult↗
PubMed1977

Cardiovascular effects of fever in the ewe and fetal lamb.

Ewes carrying fetuses with permanently implanted cannulas developed fevers following intravenous injections of bacterial pyrogen (1 microng). During the rising phase of the fever, maternal heart rate increased, but no consistent changes in mean arterial blood pressure (MABP), arterial pH, PO2, or PCO2 were observed during the course of the fever. Fetal temperature, which was initially 0.3 to 0.8 degrees C. higher than maternal temperature rose in parallel with the ewe's temperature. During the maternal fever, fetal MABP, pH, PO2, and PCO2 remained unchanged, but on several occasions the fetal heart rate developed irregularities that persisted after the fever had subsided. These observations suggest that maternal fever does not appear to have adverse effects on fetal oxygenation but has a variable effect on cardiovascular function.

Animals↗
PubMed1977

Responses to electrical stimulation, noradrenaline, serotonin, and vasopressin in the isolated ear artery of the developing lamb and ewe.

Responses of isolated helical strips of ovine ear artery to electrical stimulation of postganglionic adrenergic neurons and exogenous agonists were studied at various stages of development from 110 days of gestation through to adulthood. Only rudimentary responses were observed at 110-115 days of gestation. A parallel development of responses to noradrenaline (NA), serotonin, and lysine vasopressin began sometime after 110-115 days of gestation and continued until 133-137 days of gestation but there was little development of the latter responses until more than 3-5 days post partum. Development of responses to exogenous agonists was incomplete 2-3 weeks post partum. The development of postganglionic adrenergic responses lagged behind those to exogenous NA. Two to three weeks post partum the NA maximal response was one-third that of adult tissue whereas the response to 16 Hz (highest frequency used) was one-sixth that of adult tissue. The NA threshold concentration was lower in arterial strips of adult animals than it was in those of younger animals. The data suggest that development of functional post-ganglionic adrenergic innervation of vascular smooth muscle begins late in gestation and continues well after birth; this development is preceded by development of vascular mechanisms involved in the response to several agonists.

Age Factors↗
PubMed1977

Arterial embolization for radical tumor resection.

Two contemporary measures, selective transarterial embolization (Almgard et al. 1973) and controlled hypotensive anesthesia (Davis et al. 1974), have been combined in an effort to reduce the risk of operative bleeding in a case of massive bone and muscle resection of a highly vascular carcinoma lesion in the proximal third of the femur. This approach may be helpful in such cases.

Anesthesia, General↗
PubMed1977

Total hip replacement and femoral-head bone-grafting for severe acetabular deficiency in adults.

We performed total hip replacement in twenty-seven hips of twenty-two patients with osteoarthritis secondary to congenital dislocation, congenital dysplasia, or acetabular insufficiency due to persistent fracture-dislocation. The femoral head was used as a bone graft, attaching it to the acetabular wall to provide bone stock for reconstruction. There were few postoperative complications. In thirteen hips followed for over one year, all grafts appeared to be united and none showed evidence of resorption. Eleven of the thirteen hips were pain-free and two were slightly painful. Eleven hips had a range of motion of 90 degrees or more.

Adult↗
PubMed1976

Stimulation of bone formation in vivo by phosphate supplementation.

The effect of phosphate supplementation on bone remodeling was assessed in six mature, healthy beagle dogs. The phosphate supplement was given in divided doses orally, daily for 12 weeks in the form of a neutral potassium phosphate preparation. The dose averaged 108 mg P/kg per day, which is double the normal canine phosphorus intake. Bone remodeling was assessed by measurement, at sacrifice, of areas of cortical bone containing different color-coded tetracyclines which had been continuously administered during 12-week control and treatment periods; remodeling was assessed kinetically during the control and treatment periods by replicate studies employing 47Ca intravenously. Both techniques demonstrated that the principal effect of phosphate supplementation was a significant stimulation of bone formation. Within cortical bone, formation was doubled, from an average of 2.7% to 5.3% per year. The major location of new bone deposits was endosteal. Whole skeletal mineral accretion, measured kinetically, increased 45% above an average control value of 0.154 g/day. These studies suggest that, in the adult dog, "normal" plasma phosphate levels are suboptimal for new bone formation. Even with this short duration of administration, phosphate produced microscopic calcification of the renal parenchyma. However, there was no biochemical evidence of renal functional impairment.

Animals↗
PubMed1976

Topical hemostatic agents to reduce bleeding from cancellous bone. A comparison of microcrystalline collagen, thrombin, and thrombin-soaked gelatin foam.

In fifty-three dogs microcrystalline collagen, thrombin-soaked gelatin foam, and thrombin powder were evaluated as hemostatic agents when applied to bleeding cancellous surfaces after osteotomy of the greater trochanter using two quantitative models: one, a single osteotomy; the other, a double osteotomy. All three agents significantly reduced bleeding compared with the controls, the microcrystalline collagen being most effective. At three months there was no evidence that microcrystalline collagen and thrombin-gelatin interfered with bone healing after the greater trochanter was reattached with two wires.

Administration, Topical↗
PubMed1976

Extensive localized bone resorption in the femur following total hip replacement.

Extensive localized bone resorption within the femur was observed after four total hip replacements. The amount and location of the resorption suggested the presence of infection or tumor, but there was no evidence of either condition and the roentgenographic appearance differed from that associated with a loose uncemented endoprosthesis or a grossly loose femoral component of a total hip replacement. At reoperation the femoral components were not rigidly fixed but were only slightly loose. Histologically there were sheets of macrophages, a few giant cells, and multiple small fragments of a birefringent material, but no inflammatory cells. While the exact mechanism of this serious complication is unclear, the findings suggest that a benign, non-inflammatory, adverse tissue response can occur in relation to the femoral components of total hip replacements that are not rigidly fixed. In all four hips, reimplantation of a new total hip replacement was successful after follow-up of thirteen to eighteen months.

Aged↗
PubMed1976

A clinical evaluation of aspirin prophylaxis of thromboembolic disease after total hip arthroplasty.

Prophylaxis of thromboembolic disease using aspirin was studied prospectively in 340 patients undergoing total hip replacement, excluding those with prior thromboembolic disease. Clinical criteria were used to diagnose thrombophlebitis, while clinical criteria, roentgenography, blood-gas determinations, electrocardiography, and pulmonary vascular scanning were used to diagnose pulmonary emboli. Five patients had signs of symptoms of pulmonary emboli, all confirmed by pulmonary vascular scan. No fatal pulmonary emboli occurred. Twenty-six patients had thrombophlebitis. Without simultaneous control group, a reduction in postoperative thromboembolic disease in these patients receiving aspirin was not proved. However, the observed low incidence of clinically evident thromboembolic manifestations suggests that aspirin may be a simple and useful prophylactic agent in these patients.

Adolescent↗