Biomedical subjects
Publications and source records attributed to M D Ryan.
The maintenance of bony length is of major importance in the management of lower limb injuries in which bone loss has occurred. We report a case of the successful use of a rigid intramedullary nail with transfixion screws (the Huckstep nail) after segmental loss of bone due to a gunshot injury.
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A case of eosinophilic granuloma in the humerus of a three and a half year old boy is described with serial roentgenographic evidence of the lesion developing over a period of two months prior to the commencement of treatment. After open biopsy and local steroid injection the lesion was observed to heal during the next ten months.
Batches of soluble antigen prepared by mechanical disintegration of Aspergillus fumigatus reproducibly contained identical protein components on polyacrylamide gels. This consistency was ascribed to standardization at the procedure for disruption: there was little variation in the protein patterns obtained from A. fumigatus mycelium grown for times varying from one to seven days at temperatures from 27 to 37 degrees C. Rabbit antisera to different A. fumigatus antigen preparations varied in their reactivity in crossed immunoelectrophoresis tests, but line immunoelectrophoresis indicated that all the antisera contained the same qualitative antibody components to the fungus. All but one of these components appeared to be present in serum samples from two patients with invasive pulmonary aspergillosis and high precipitin titres to A. fumigatus. The data suggest that many antibodies with different specificities are formed in response to aspergillosis in vivo, so that most preparations of A. fumigatus antigens are likely to contain at least one component capable of detecting antibodies to the fungus for diagnostic purposes.
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In vitro wear data were determined for nine experimental composites and compared with two-year clinical data. The in vitro tests included single-pass wear and two-body abrasion. The in vivo data were obtained between 1978 and 1980 for 54 class 2 posterior composite restorations in 25 patients. Correlations between the in vitro and in vivo data were found with values of alpha less than 0.08.
Twenty-eight patients with thoracolumbar fractures treated by open reduction and internal fixation with Harrington instrumentation are reviewed. An unresolved problem is the selection of patients for surgical management. It is a major operation requiring a surgeon experienced in both the care of spinal cord injuries and the use of spinal instrumentation. The technique permits more rapid mobilization, retraining and rehabilitation than nonoperative management.
Acute myelopathy is a rare complication of Scheuermann's disease. Three patients are reported where spinal cord compression occurred at the apex of a kyphos. All were male, aged 14, 18 and 20 years, and each had a profound neurological defect associated with a short, sharp kyphos in the low thoracic region. Each patient underwent anterior decompression and all made an almost full recovery. It is deduced that factors which may influence the onset of cord compression include the angle of kyphosis, the number of segments involved, the rate of change of the angle, local anatomical variations, trauma, and possible secondary impairment of the vasculature of the cord.
Twenty-three adults with fractures of the odontoid process are reviewed. Te possible reasons for the high rate of non-union in reported series are considered: these include the type of fracture, its displacement, the presence of a gap at the fracture site, imperfect reduction and inadequate immobilisation. Type 2 fractures (at the base of the odontoid process) are the commonest and also the most liable to nonunion. In their treatment, reduction is important; as seen in the lateral radiograph at least two-thirds of the fracture surfaces should be in contact. Skull traction is not advised and halo-cast fixation is the treatment of choice; with this method 87.5 per cent of recent odontoid fractures united.
Distraction fractures of the upper lumbar spine are most often associated with the wearing of seat-belts. Twenty patients with this spinal fracture were reviewed and half of them had intra-abdominal injuries. Eight patients required an exploratory laparotomy. Three distinct patterns of distraction fractures have been identified. Open reduction, local spinal fusion and Harrington instrumentation are recommended for unstable fractures and for those with neurological involvement. Four cases of non-union are included ln the series. Legislation for the compulsory wearing of seat-belts should encompass improvements in design and stricter criteria for installation.
Sciatica is one of the most incapacitating and difficult to treat of all benign pains. This is a report of the results of using epidural and intrathecal corticosteroids in depot form, methylprednisolone acetate (Depo-Medrol), in 108 patients who presented with a clinical diagnosis of acute lumbar disc prolapse and nerve-root pain. There was a 75% response rate in patients with less than four weeks of symptoms, whereas in patients with more than six weeks of symptoms the rate dropped to 43%. Patients with a high level of protein in their cerebrospinal fluid appeared to have a higher response rate. The treatment is most likely to be effective when the patient is male, the duration of symptoms is less than four weeks, and the patient has irritant rather than compressive neuropathy.
A recent and important approach to investigating electron transfer mechanisms of redox proteins has been through kinetic-ionic strength studies. There is, however, significant controversy as to whether such studies (1) yield information regarding the charge (or location) of the electron transfer site or (2) more simply reflect the influence of net or overall protein charge on the electrostatic interactions. A critical analysis using different theoretical approaches is made of our recent work and of the bulk of the published non-physiological small molecule-protein and protein-protein kinetic ionic strength studies; it is concluded that (1) the approximated Bronsted-Debye-Huckel equation can not be used at all for protein redox reactions, (2) irrespective of the theoretical approaches discussed, such studies do not provide information regarding the charge of the electron transfer site, (3) it is the net charge of the reactants that control the electrostatic interactions, (4) both the equation derived by Wherland and Gray and the full Bronsted-Debye-Huckel equation provide reasonably good approximations of net protein charge, (5) pH changes quantitatively modulate net protein charge, and (6) thus, protein redox rates need to be electrostatically corrected if relevant interpretations of kinetic-ionic strength experiments are to be made.
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A simple approach to the distal lumbar spine for disc excision is described and the relevant surgical anatomy reviewed. The approach is considered to have many advantages over formal laminectomy for the same purpose in the majority of cases. The indications and contraindications for its use are discussed.
A review of 49 cases of haematogenous osteomyelitis of the spine has indicated the need for planned investigations to establish a bacteriological diagnosis and appropriate antibiotic therapy. The data suggest that antibiotics may not influence the outcome in patients presenting with a chronic infective process, particularly when this is located in the lumbar region.
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