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Biomedical subjects

K C Chan

Publications and source records attributed to K C Chan.

At least 109 records · Page 6Linked to original sources
PubMed1989

Psychosocial factors influencing outcome in patients with low-back pain.

A psychosocial analysis of 58 patients with low-back pain was conducted. Three groups of patients with different outcomes were delineated with distinctly different psychosocial profiles. Patients who recovered uneventfully had a better income, reported more satisfaction with hospitalization or medical personnel, and had prolonged pain-free periods. Patients with the worst outcomes in terms of poor work role adjustment and severe pain complaints were more likely to be immigrants from mainland China, to be engaged in heavy manual labor, to be involved in compensation claims for work-related injuries, manifested a high degree of anxiety and depressive symptoms, and were hostile toward medical personnel. An intermediate group of patients with adequate work role adjustment but severe to moderate levels of pain were characterized by being females with varying combinations of anxiety and depressive symptoms. A preliminary clinical interview guide for screening potential problematic patients was developed.

Adult↗
PubMed1989

Propranolol induced bradycardia in tetralogy of Fallot.

When an 18 month old girl who had tetralogy of Fallot and episodes of severe cyanosis with loss of consciousness was treated with propranolol there was some improvement. But when the dose was increased she had further episodes of near syncope. Holter monitoring showed extreme intermittent bradycardia with pauses of up to 2.6 seconds. The episodes of near syncope and the bradycardia resolved after propranolol was stopped. Apparent failure of propranolol treatment may on rare occasions be related to drug induced bradycardia rather than to continued episodes of severe cyanosis.

Bradycardia↗
PubMed1989

Curing light-activated composite cement through porcelain.

The purpose of the study was to determine the exposure times needed to harden a light-activated composite cement through various thicknesses of porcelain. A negative exponential model was developed with which the relative hardness of a composite could be predicted from the product of the exposure time and the square root of the light intensity at 470 nm. Hardness data obtained by varying the exposure time and porcelain thickness were found to fit this model. A relationship was derived to predict the required exposure time, t, of a composite under porcelain with a transmission coefficient, Tc, and a thickness, l:t = toTc-1/2, where to is the exposure time of the composite alone.

Composite Resins↗
PubMed1988

Myelin basic protein binds GTP at a single site in the N-terminus.

Myelin basic protein from normal human brain was ADP-ribosylated with Cholera toxin, but not with Pertussis toxin. It bound azido-GTP at a single site in the N-terminal tetrapeptide at the Gln residue. The binding was considerably reduced when GppNHp was present during azido-GTP binding and totally inhibited when GTP gamma S was present. The relevance of this specific binding is not understood at this time.

Adenosine Diphosphate Ribose↗
PubMed1988

Tumour infiltrating lymphocytes in nasopharyngeal carcinoma.

Tumour infiltrating lymphocytes were studied in 28 cases of undifferentiated carcinoma using a panel of monoclonal antibodies. For the T subsets we used OKT4 (helper/inducer), 8 (suppressor/cytotoxic), 11 (pan T), 9 (transferrin receptor) and Dako T6. For the B cells we used polyclonals IgM, D, G and A. Others were HNK-1 (natural-killer cells), THB-5 and W6/32 (HLA-ABC) and HLA-DR. Most of the lymphocytes were T cells and in 26 of 28 biopsies there were more T8 than T4 cells which could be seen around and within the tumour masses. There was also an increase in HNK and T6 cells. Tumour cells were positive for both W6/32 and HLA-DR. Occasional THB-5 positive cell could be seen within tumour masses. All tumour cells stained strongly with keratin and cytokeratin.

Antibodies, Monoclonal↗
PubMed1988

Effusions in the knee in elderly patients who were operated on for fracture of the hip.

The incidence of an effusion in the knee in 155 consecutive elderly patients who had been operated on for a proximal femoral fracture was studied. The preoperative incidence had been 7.7 per cent in the ipsilateral knee and 1.3 per cent in the contralateral knee. Postoperatively, fifty patients (32.3 per cent) had an effusion on the ipsilateral side. In seven of them, the effusion had been present before the operation. All of the effusions subsided completely within three weeks after the operation. Results of the laboratory analysis of a specimen of the effused material from eight patients who were chosen at random showed non-inflammatory fluid. Probably the effusions were traumatic in origin, and it is likely that they were a response to stresses that had been incurred during the operation or at the time of fracture.

Aged↗
PubMed1987

Treatment of unstable intertrochanteric fractures with Sarmiento valgus osteotomy and acrylic cement augmentation.

Seventy unstable intertrochanteric fractures (Kyle III) were treated by Sarmiento valgus osteotomy, fixation with a sliding hip-screw and plate, and augmentation of the posteromedial upper femoral defect with acrylic cement. Immediate full weight bearing walking was started after the operation. Forty-two patients were followed up for more than 1 year (average 21.4 months). Excellent or good results were obtained in 71.4 per cent. However, there was mechanical failure in which the hip screw cut out of the femoral head superolaterally in 8.6 per cent. Comparison was made between the results of the present technique and our previously reported technique which consisted of Dimon-Hughston medial displacement osteotomy, fixation with sliding hip screw and acrylic cement augmentation to the upper posteromedial femoral defect. It was found that the result of the latter technique is slightly better, probably because of the more rigid reduction.

Aged↗
PubMed1986

Reconstruction of the lateral tibial condyle by a pedicled vascularized fibular graft after en bloc resection of giant cell tumour.

Two patients with giant cell tumour of the lateral tibial condyle underwent en bloc resection and reconstruction by pedicled vascularized fibular graft. Both had good functional results and rapid solid bony union. This procedure preserved the lateral stabilizing structures of the knee, allowed relatively early mobilization and provided some cartilagionous surface for articulation with the lateral femoral condyle. The procedure was technically simple compared with homograft reconstruction, prosthetic replacement or free vascularized bone grafts, and could be performed in less sophisticated centres. The operation also provided additional bone stock for subsequent fusion if necessary.

Adult↗