Biomedical subjects
Publications and source records attributed to M E Foster.
A method of external cranio-maxillary fixation using orthodontic appliances is described, which is particularly suitable for surgical cases where additional vertical stability is required.
The influence of magnetized foil strips (Energy-Pak Ltd., Wolfhalden, Switzerland) on soft-tissue healing in the skin of laboratory rats was studied. Linear sutured wounds healing by primary intention have been assessed for tensile strength using Instron tensiometry, and open full-thickness defects healing by secondary intention have been analyzed for collagen content, histologic appearance, and rate of healing. Wounds were covered by the alternate magnetic Energy-Pak foil or by a dummy control. No differences in tensile strength, collagen content, histologic studies, or rate of healing were seen between the treated and control groups.
Tumorigenicity of human lymphoma and lymphoblastoid B-cell lines was assessed by their ability to form growing and transplantable masses on subcutaneous inoculation into neonatally thymectomized, Ara-C-protected, total-body-irradiated mice. By these criteria, 12 lines of known malignant origin were tumorigenic, 11 lymphoblastoid lines, tested after less than one year of in vitro growth, were non-tumorigenic and 8/18 long-established lymphoblastoid lines produced transplantable tumours. All of the long-established lines had acquired karyotypic changes on prolonged culture, the predominant characteristic being a gain of whole chromosomes or of major chromosome segments. None showed the classical 8:14 translocation associated with Burkitt's lymphoma. Comparisons with nontumorigenic precursors (recovered from liquid nitrogen storage) and with other non-tumorigenic but chromosomally abnormal, lymphoblastoid lines suggest that imbalance of the dosage of genes carried on chromosomes 7,8 and 9 may be important in determining the tumorigenic phenotype.
In this study we report the effects of flurbiprofen and prostaglandin E2 on anastomotic tensile strength, collagen synthesis, and collagenolytic activity which are in a particularly fine balance in colonic healing. Colonic anastomoses were fashioned in 150 Sprague-Dawley rats which were allocated to receive either 20 mcg prostaglandin E2 in 1 ml saline, 1 ml saline alone (control) intraperitoneally for three days post-operatively, or oral 2.5 mg/kg flurbiprofen daily. Anastomotic bursting pressures, collagen content and collagenolytic activity were measured at three, six, and ten days. It was found that prostaglandin E2-treated animals had significantly weaker anastomoses at three days (102 +/- 6.1 mm Hg; m +/- SEM) compared with the control (126 +/- 7.3; P less than 0.02) or flurbiprofen group (128 +/- 4.6; P less than 0.01) with no differences at six and ten days. Collagen levels were higher in flurbiprofen-treated rats at three days (9.7 +/- 0.2 micrograms hydroxyproline/mg tissue) compared with the control (8.1 +/- 0.4 micrograms/mg; P 0.01) or prostaglandin E2 group (7.2 +/- 0.5 micrograms/mg; P 0.001). These differences were unchanged at six days but were not statistically different at ten days. Collagenolytic activity showed no differences in the three groups during the study. It is concluded that flurbiprofen enhances colonic healing with improved collagen synthesis without affecting collagenolytic activity.
Anastomotic leakage is particularly common in low anterior resection. This may be due to poor blood supply of the cut ends. Eighteen angiograms of the rectum were studied and a midline paucity of vessels was found both anteriorly and posteriorly. This may provide an anatomic explanation for dehiscence.
The prolonged use of a hydrogel (polyacrylamide) dressing on circular 1 cm skin defects was tested in a rat experimental model. The rate of healing and changes in bacterial content following inoculation of 1 X 10(8) Staphylococcus aureus, Escherichia coli or Pseudomonas aeruginosa were measured. Wounds inoculated with Staph. aureus or E. coli prior to polyacrylamide occlusion did not have delayed wound contraction and healing and numbers of organisms were falling at 10 days. Wounds inoculated with Ps. aeruginosa showed a delay in healing with a large increase in organisms (greater than 1 X 10(10] after 10 days occlusion. Prolonged wound occlusion by hydrogel dressings may aid in healing by secondary intention but the presence or growth of pseudomonas indicates that frequent changes of dressings should be made.
The effectiveness of three methods of operative cholangiography in outlining biliary anatomy was assessed in 60 patients undergoing routine cholecystectomy for gallbladder calculi. X-rays were scored according to bile duct visualization and an overall score calculated. There were no statistically significant differences between the three groups. However, ductal opacification was inadequate in a majority of patients. It is suggested that closer cooperation with the radiologist and more emphasis on technique are required if cholangiography is used to identify unsuspected calculi.
A method is described for the study of microangioneogenesis in wounds healing by secondary intention. Standard skin defects were created on the backs of Sprague-Dawley rats and angiograms of the new vessels in the healing wounds were performed at subsequent time intervals. The technique allowed comparison of the rate of new vessel formation in wounds covered with a hydrogel surgical dressing with those healing without a dressing. It was found that the rate of new capillary formation was faster in the covered wounds.
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A case of acute urinary retention due to a vesical leiomyoma is described. This is an unusual presentation and the treatment is discussed.
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Marfan's syndrome is a rare hereditary disorder characterized by skeletal, cardiovascular and ocular abnormalities. Pulmonary abnormalities occur in approximately 10% of patients the commonest being spontaneous pneumothorax and emphysema. A patient is described who had Marfan's syndrome and bronchiectasis, an association only described on 2 previous occasions in the literature.
Serum cephaloridine concentrations were measured in the immediate post-operative period in 23 patients who had received a prophylactic dose of 1 g of the drug into the wound at the end of operation. Eleven patients received the antibiotic as a powder and 12 as a solution. The serum concentrations were higher, though not significantly so, in the group receiving powder, and this is thought to be due to the lesser amount of spillage and loss into dressings when the antibiotic is given in this form.
Eleven patients are described in whom myelomatosis was complicated by the laboratory and clinical features of the hyperviscosity syndrome (HVS). The myeloma type was IgA in nine and IgG3 in two. In those patients with IgA myeloma the HVS was related to the presence of high molecular weight complexes in the serum. Remission of clinical features was obtained in all patients by plasma exchange. Clinical improvement coincided with reduction of whole blood viscosity and in those patients with IgA myeloma, with a parallel reduction of the high molecular weight complexes. The relationship between the IgA complexes and blood viscosity has been examined by physicochemical analysis of purified IgA monomer and polymers and evidence is presented to show that the IgA polymer has a higher intrinsic viscosity and axial ratio than the larger IgM molecule. The significance of these observations is discussed.
The name cicatricial mucosal pemphigoid is suggested in an attempt to clarify several synonymous terms and to omit the prefix "benign." The clinical features are reviewed and seven case reports illustrating different aspects are presented. The severe effects of ocular and pharyngeal involvement are highlighted, immunologic findings and treatment are discussed, and the link with neoplasia is emphasized.
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