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Biomedical subjects

H W Hamilton

Publications and source records attributed to H W Hamilton.

30 records · Page 2Linked to original sources
PubMed1986

Prosthetic position in total hip replacement.

The AP radiographs of 230 total hip replacements were studied to determine how often the prostheses were correctly positioned. It appeared that the inclination of the prosthesis was less important than the position of the center of rotation of the arthroplasty. A new method of measurement was applied to the preoperative and postoperative radiographs of 85 patients with unilateral hip disease and no previous operations. Correction of migration of the center of rotation of the arthritic hip, coverage of the center of rotation, and leg length were determined and related to the function of the arthroplasty. The method emphasizes the importance of the center of rotation and answers the questions: Does the design of the prosthesis allow the center of rotation to be placed in the desired position and did the surgeon place the prosthesis in such a position?

Biomechanical Phenomena↗
PubMed1986

Long-term results of low-friction arthroplasty performed in a community hospital, including a radiologic review.

This report is a prospective review of 450 low-friction arthroplasties (LFAs) performed by a single surgeon from 1972 to 1983 in a community hospital. The clinical results show sustained quality of the result over a maximum follow-up period of 11 years. The radiologic review shows a slight increase in the number and size of radiolucent lines with time. Bacteriologic studies confirm that clean-air technology reduces the bacteriologic contamination of the operating room and the wound. Deep infections occurred in 1.6% of cases. The most notable complication was failure to obtain bony union of the osteotomized trochanter in 14% of cases. The revision rate for aseptic loosening of the cup was 0.7% and of the femoral prosthesis 0.0%.

Adult↗
PubMed1985

Synthesis of xanthines as adenosine antagonists, a practical quantitative structure-activity relationship application.

A set of 56 8-phenylxanthines, previously tested for adenosine antagonism (adenosine A1 receptor affinity), was analyzed by quantitative structure-activity relationship (QSAR) techniques. The resulting QSAR revealed that (1) the most potent receptor binders had already been made in this series and thus suggested the termination of synthesis of compounds with additional phenyl substituents to increase potency and (2) potency was much more strongly affected by changes in ortho than para phenyl substitution. On the basis of this study, an additional 20 compounds were synthesized that contained primarily para substituents designed to increase aqueous solubility. High potency was maintained among the resulting sulfonamide derivatives (as predicted by the QSAR), and aqueous solubility was dramatically increased. Furthermore, in vitro antagonism of an adenosine receptor mediated physiological effect was demonstrated.

Adenosine↗
PubMed1984

Clinical application of basic research on continuous passive motion for disorders and injuries of synovial joints: a preliminary report of a feasibility study.

Since 1970, when the concept of continuous passive motion (CPM) was originated by one of the authors (R.B.S.), he and a succession of his research fellows have investigated its biological effects on the healing and regeneration of articular tissues in a wide variety of experimental models in rabbits. From this basic research he concluded that CPM is well tolerated, seems to be painless, stimulates the healing and regeneration of articular tissues, prevents joint stiffness, and permits the normal healing of arthrotomy incisions. Beginning in 1975, one of the authors (H.W.H.), and in 1978, the remaining authors, (from two additional Canadian cities) applied the knowledge from the basic research on CPM to the orthopaedic care of human patients. The CPM devices for humans (CPM Mobilimbs), which have been designed in collaboration with University of Toronto engineers, include, to date, devices for the ankle-knee-hip, the elbow, and the finger. Indications for CPM in patients have been the immediate postoperative management following such operative procedures as open reduction and internal fixation of fractures, arthrotomy and arthrolysis for post-traumatic arthritis, synovectomy, surgical drainage for septic arthritis, release of extraarticular contractures, metaphyseal osteotomies, total joint replacement, and ligamentous reconstruction. The case reports of nine selected patients are presented as examples of the clinical application of CPM. These patients have been relatively free of pain, have maintained the increased motion gained at operation, and have accepted the application of CPM well. There have been no complications of CPM; the operative wounds have healed well and the period of hospitalization has not been prolonged. The authors believe that the clinical application of CPM is feasible and that the clinical and radiographic results of CPM in these patients are encouraging. Long-term, prospective clinical investigations (including control patients in whom CPM is not used) will be required to assess the efficacy of CPM in relation to the various stated indications.

Adolescent↗
PubMed1983

C4-substituted 1-beta-D-ribofuranosylpyrazolo[3,4-d]pyrimidines as adenosine agonist analogues.

The synthesis of four novel C4-substituted 1-beta-D-ribofuranosylpyrazolo[3,4-d]pyrimidines is reported, and the compounds were examined as adenosine receptor agonist analogues. Neither receptor affinity nor biological activity was as potent as the purine counterparts. Adenosine agonists appear to be sensitive to modification of the purine base, with a nitrogen atom in the 7 position necessary for efficacy.

Adenosine↗
PubMed1979

Penetration of gown material by organisms from the surgical team.

The routes by which viable organisms shed by the surgical team reach the wound are not yet fully understood. Bacteriologic studies show that shedding is greater in surgeons than their assistants or scrub nurses, and is increased by activity and temperature, but is primarily related to the individual's shedding characteristics. Comparison of the ability of 3 types of cotton gowns to contain the surgical team's bacterial effluent shows that the body exhaust system gowns developed by Charnley are superior to more conventional gowns. It is clear that viable organisms can penetrate very closely woven Ventile (pore size 10 microns) as well as balloon cloth (pore size 50 microns). Ventile used without a body exhaust system does not appear to increase gown efficiency. Penetration of gown material by organisms from the surgical team is responsible for 20% of wound contamination. The gown glove cuff junction is an important leakage point for organisms shed by the surgical team. A newly designed "mitt" cuff more effectively seals this area than the conventional stockinette cuff.

Clothing↗
PubMed1977

Preoperative hair removal.

This study compares the efficiency, safety and cost of hair removal before surgery, with a safety razor, an electric clipper and a depilatory. It was found that both the razor and the clipper damaged the surface of the skin, while the depilatory caused a mild lymphocytic reaction in the upper dermis. The depilatory was expensive and may cause sensitivity reactions in a few individuals, but was found to be the easiest and most efficient method of removing hair. It was concluded that if hair has to be removed a depilatory is the agent of choice.

Costs and Cost Analysis↗