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Biomedical subjects

T O'Brien

Publications and source records attributed to T O'Brien.

At least 181 records · Page 10Linked to original sources
PubMed1990

The importance of standardised radiographs when assessing hip dysplasia.

The reliability of radiological criteria in the diagnosis of congenital dislocation of the hip is discussed. In a review of 20 normal infant patients the variability of the radiographic relationship between the ossific nucleus of the proximal femoral epiphysis and the acetabulum is identified. Hip arthrography in 10 patients and pathological examination of femoral heads confirm that the ossific nucleus lies superiorly within the infant femoral head and may be displaced from the true centre of the femoral head by up to 40% of it's radius. As the ossific nucleus of the capital femoral epiphysis is shown to originate eccentrically within the spherical cartilaginous anlage it is suggested that standardisation of hip radiographs is required in the routine clinical assessment of the infant hip, particularly in the presence of dysplasia.

Arthrography↗
PubMed1990

The technique of gait analysis using a Coda-3 motion analysis system.

Gait analysis using Code-3 provides information which allows individual gait to be characterised with little interference to the patient. It is an ideal method for analysing gait in patients with cerebral palsy. Because of the ease with which this information is now available using Coda-3, gait analysis can now be performed on all ambulant patients in whom surgery is contemplated.

Biomechanical Phenomena↗
PubMed1989

Scutting: a dangerous pastime?

Scutting is a pastime which has taken place in Dublin for many years. To scutt is to gain a ride on the back of a moving vehicle holding onto it by any means possible. Injuries sustained while scutting have never previously been reported. A total of 38 children presented at the Accident and Emergency Department of The Children's Hospital, Temple Street during the period January 1985 to July 1987 with injuries sustained while scutting. The injuries were analysed with regard to type, pattern, severity and outcome; nine children died from their injuries and 34.2 per cent of the children were admitted to hospital with an average stay of 5 days. All of those admitted alive made a full recovery. Comparison is made with other more everyday sensible pastimes and with road traffic accidents involving children. Scutting is shown to be the most dangerous pastime and is responsible for more deaths than any other type of road traffic accident involving children. Suggestions are made to stop this pastime taking place.

Accidents, Traffic↗
PubMed1989

Oxygen-dependent differences in exopolysaccharide production and aminoglycoside inhibitory-bactericidal interactions with Pseudomonas aeruginosa--implications for endocarditis.

Antibiotic-induced growth inhibition and killing of a non-mucoid strain of Pseudomonas aeruginosa (PA-96) in vitro and ex vivo were studied at oxygen tensions approximating those of the right and left cardiac ventricles in vivo (pO2 = 40 VS. 80 mm Hg). This pseudomonal strain grew equally at the two oxygen tensions, yet only bacteria exposed to pO2 80 mm Hg revealed significant exopolysaccharide production as shown by PAS and ruthenium red staining. Similarly, scanning electron microscopy of pseudomonal cells within aortic (but not tricuspid) vegetations revealed surface excrescenses compatible with surrounding exopolysaccharide (glycocalyx). Amikacin at 10 x MIC caused significantly less in-vitro killing of pseudomonal cells at pO2 80 VS. 40 mm Hg. In vitro and ex vivo (within experimental aortic and tricuspid vegetations), post-antibiotic effect durations were about 50% shorter for cells exposed to amikacin at pO2 80 mm Hg than 40 mm Hg. These data demonstrate suboptimal aminoglycoside-induced growth inhibition and killing, as well as enhanced exopolysaccharide production of a non-mucoid P. aeruginosa strain at oxygen tensions reflective of the left side of the heart. These findings may in part explain the better results seen in aminoglycoside-treated right compared to left-sided pseudomonal endocarditis in man.

Amikacin↗
PubMed1989

Radiographic changes in the ossific nucleus in congenital dislocation of the hip.

Twenty one patients with a delayed diagnosis of congenital dislocation of the hip were studied to assess the relevance of radiographic changes in the ossific nucleus of the proximal femur during the first year following treatment. All abnormal hips demonstrated sclerosis of the margins of the ossific nucleus with irregularity of its surface at three months following surgery. In nineteen patients a head within a head was identified. These common changes are interpreted as the radiographic appearance of a spherical growth disturbance line formed by the ossific nucleus. It is concluded that these radiographic changes which are often accepted as indicators of avascularity are of no detrimental significance in the absence of physeal injury.

Epiphyses↗
PubMed1988

Kinetic effects of adriamycin and bleomycin on two osteosarcoma models.

Although chemotherapeutic drugs are frequently administered to patients with osteosarcoma, there has been little research into the effect of cytotoxic drugs on osteosarcoma cell biology. The effect of two drugs (Adriamycin and bleomycin) on cell cycle kinetics was investigated in vitro in an established line of human osteosarcoma cells and in vivo using the Dunn osteosarcoma model. The cell cycle changes were consistent with G2 arrest for both drugs in vivo and in vitro. The alteration in cell cycle distribution was correlated with inhibition of 3H-thymidine incorporation in vitro. In vivo, the greater change in cell cycle distribution caused by Adriamycin was reflected in the increased inhibition of tumor growth found with this drug.

Animals↗
PubMed1988

Salter-Harris type III fracture of the proximal humeral physis.

Salter-Harris type III, IV and V injuries of the proximal humeral physis are rare. We report an undisplaced Salter-Harris type III injury of the humeral head physis in a 10-year-old girl. The fracture united with non-operative treatment.

Accidents, Traffic↗
PubMed1988

Growth disturbance lines after injury of the distal tibial physis. Their significance in prognosis.

We reviewed 26 fractures involving the distal physis of the tibia to identify the patterns of formation and displacement of the subsequent growth disturbance lines. Twenty-one patients showed a regular "normal" pattern of line and healed with no deformity. Three patients had medical physeal arrest revealed by abnormal lines. Two other cases had a minor central physeal arrest without subsequent deformity. The pattern and character of the growth disturbance line can provide an early warning of potential deformity.

Adolescent↗
PubMed1987

Initial clinical experience with degradable starch microspheres.

Four patients with advanced hepatic malignancy have been investigated with a view to intra-arterial treatment with degradable starch microspheres (DSM) and mitomycin-C (MMC). Computer-assisted interpretation of data gathered during the administration of technetium-labelled albumin allows the degree of arteriovenous shunting within the liver to be measured. In a similar way, the effectiveness of DSM in blocking hepatic arterial flow is determined. Two patients showed unacceptably high levels of shunting (75% and 100%) and were excluded from further study. One patient with hepatocellular carcinoma shunted only 24% of the macroaggregated albumin, and flow through the liver was reduced to 48% by DSM therapy. This patient has undergone four courses of MMC without significant toxic complications. The last patient had 25% shunting. The DSM titration and the first MMC administration had to be abandoned because of severe abdominal pain and nausea related to a fracture of the intra-arterial catheter. Complications directly associated with the procedures have been acceptable. The relationship between flow reduction and the amount of DSM administered is non-linear, and the appropriate dose of DSM for each treatment must be titrated against both the patient's symptoms and the computer-generated flow indices.

Adult↗
PubMed1986

Osteoid osteoma: localization by intraoperative magnification scintigraphy.

Surgical localization of osteoid osteomas is a major problem in the diagnosis and therapy of this lesion. Visual, tactile, and radiographic localization is often equivocal and as a consequence incomplete excision of the tumor, or excessive removal of bone may result. We performed magnification intraoperative bone scintigraphy using a portable gamma camera and a radioactive pointer in six patients with osteoid osteoma. Accurate localization and complete removal of the tumor was achieved in all six with only minimal delays in the surgical procedure. The advantages of this technique and recommendations for its use are discussed.

Adolescent↗
PubMed1986

The early identification and classification of growth disturbances of the proximal end of the femur.

An analysis of the serial radiographs of sixty-eight patients who were treated for congenital dislocation of the hip revealed that a growth disturbance of the proximal end of the femur that was caused by partial or complete physeal closure developed in thirty-three of these patients. The disturbances were related to the character of the metaphyseal growth-disturbance lines and were subsequently classified according to the site and extent of physeal closure. In order to study this problem, we divided the physis of the proximal end of the femur into two contiguous sections: a medial and a lateral portion. Two typical patterns of premature closure were identified: one located at the junction of the medial and lateral portions of the physis and the other located in the area of the medial portion of the physis alone. The pattern of physeal closure, together with the age of the patient at the time of closure, determines the subsequent growth of the proximal end of the femur. The final outcome of growth of the proximal end of the femur can be predicted within six months after the initial treatment. Epiphyseal changes were found to be of no prognostic significance in the absence of physeal closure.

Adolescent↗
PubMed1985

Growth-disturbance lines in congenital dislocation of the hip.

In congenital dislocation of the hip, growth-disturbance lines as shown radiographically regularly occur in the proximal end of the femur after operative procedures are performed under general anesthesia. They can be seen in children who are between the ages of six months and four years and tend to disappear over several years. I think that the final shape of the femoral neck can be predicted by closely observing the development and displacement of the growth-disturbance lines that are induced at the time of surgical treatment.

Child, Preschool↗
PubMed1984

UV-induced reversion of his4 frameshift mutations in rad6, rev1, and rev3 mutants of yeast.

The UV-induced reversion of two his4 frameshift alleles was much reduced in rad6 mutants of Saccharomyces cerevisiae, an observation that is consistent with the hypothesis that RAD6 function is required for the induction of all types of genetic alteration in misrepair mutagenesis. The reversion of these his4 alleles, together with two others of the same type, was also reduced in rev1 and rev3 mutant strains; in these, however, the extent of the reduction varied considerably with test allele used, in a manner analogous to the results in these strains for base repair substitution test alleles. The general features of UV-induced frameshift and substitution mutagenesis therefore appear quite similar, indicating that they may depend on related processes. If this conclusion is correct, greater attention must be given to integrating models which account for the production of nucleotide additions and deletions into those concerning misrepair mutagenesis.

Base Composition↗
PubMed1984

An ultrastructural examination of non-lymphoid host cells of Moloney murine leukaemia virus of CFW/D mice.

An ultrastructural examination of various tissues from CFW/D mice, neonatally injected with Moloney murine leukaemia virus (Mo-MuLV) revealed the presence of type C virus particles budding from the membranes of various bone marrow-derived cells, pancreatic acinar cells, beta cells, and submandibular gland acinar cells. These observations indicate that Mo-MuLV has the potential to replicate in non-lymphoid cell types even when acquired post-partum. In the pancreas, a large accumulation of immature and mature viral particles was observed between the cell membranes of the acinar cells and the basal lamina. A similar accumulation of viral particles was observed in the lumina of the acinus of submandibular glands. The role of murine leukaemia viruses as potential mediators of aberrations of non-haemopoietic tissues and an alternative mode of viral transmission are discussed.

Animals↗