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Biomedical subjects

S Bourne

Publications and source records attributed to S Bourne.

At least 19 recordsLinked to original sources
PubMed2001

Differentiation of osteoblasts and in vitro bone formation from murine embryonic stem cells.

Pluripotent embryonic stem (ES) cells have the potential to differentiate to all fetal and adult cell types and might represent a useful cell source for tissue engineering and repair. Here we show that differentiation of ES cells toward the osteoblast lineage can be enhanced by supplementing serum-containing media with ascorbic acid, beta-glycerophosphate, and/or dexamethasone/retinoic acid or by co-culture with fetal murine osteoblasts. ES cell differentiation into osteoblasts was characterized by the formation of discrete mineralized bone nodules that consisted of 50-100 cells within an extracellular matrix of collagen-1 and osteocalcin. Dexamethasone in combination with ascorbic acid and beta-glycerophosphate induced the greatest number of bone nodules and was dependent on time of stimulation with a sevenfold increase when added to ES cultures after, but not before, 14 days. Co-culture with fetal osteoblasts also provided a potent stimulus for osteogenic differentiation inducing a fivefold increase in nodule number relative to ES cells cultured alone. These data demonstrate the application of a quantitative assay for the derivation of osteoblast lineage progenitors from pluripotent ES cells. This could be applied to obtain purified osteoblasts to analyze mechanisms of osteogenesis and for use of ES cells in skeletal tissue repair.

Animals↗
PubMed1998

Supracostal percutaneous nephrolithotomy for upper pole caliceal calculi.

The incidence of upper pole calculi is 15% of all caliceal calculi. The management of such calculi has been simplified since the advent of extracorporeal shockwave lithotripsy (SWL). In our experience, however, there is a subset of upper pole caliceal calculi wherein certain features can render SWL less than adequate treatment, namely diameter >1.5 cm, narrowing of the caliceal infundibulum, either singly or combined, and morbid obesity. In such instances, percutaneous nephrolithotomy (PCNL) is indicated. Percutaneous access to an upper pole calix can be difficult by a subcostal track. The supracostal 12th rib approach provides direct and efficient access to an upper pole calix and is ideally suited for upper pole calculi. Twenty-one patients with large or complex upper pole calculi were treated by supracostal PCNL. The maximum diameter of the calculi ranged from 7 to 40 mm. Eight were branched (staghorn). There was one horseshoe kidney, and calculi were bilaterally represented in another patient. Two patients were morbidly obese. All procedures were performed in one stage under general anesthesia. Following cystoscopy and ureteral catheterization, the upper pole calix was accessed directly with the aid of C-arm fluoroscopy and retrograde ureteral contrast injection. The percutaneous tract was dilated to a maximum of 26 F, a working sheath was inserted, and the calculi were extracted after ultrasonic or pneumatic fragmentation. One patient required secondary SWL for residual fragments. There were no intrathoracic complications, and blood loss was minimal. Large or complex upper pole caliceal calculi, particularly in the morbidly obese, can be treated effectively by PCNL using supracostal percutaneous access.

Follow-Up Studies↗
PubMed1998

Screening for unhealthy lifestyle factors in the workplace.

OBJECTIVE: To examine (1) the prevalence of four lifestyle behaviours among Australia Post employees and (2) employees' perceptions of the role of the workplace in promotion of lifestyle change. DESIGN: A cross-sectional survey using a self-administered questionnaire involved 688 employees working in Australia Post throughout metropolitan Sydney. MAIN OUTCOME MEASURES: Prevalence related to age and sex of alcohol consumption, cigarette smoking, inadequate exercise, perception of excessive weight. RESULTS: 36% of men and 11% of women reported drinking alcohol at levels considered hazardous or harmful; 33% of men and 25% of women reported smoking; 51% of men and 62% of women thought they were overweight; 30% of men and 39% of women did not exercise regularly. Younger respondents were more likely to report drinking hazardously or harmfully, were smokers and had multiple risk factors. A majority of respondents thought that their employer should be interested in employee's lifestyle issues, particularly excessive drinking (63%). However, few considered seeking advice from the workplace regarding smoking (16%), weight (25%) and excessive alcohol consumption (12%). CONCLUSIONS: These results show that many of Australia Post employees have unhealthy lifestyle behaviours. While employees perceive that the workplace has an important role in promoting healthy lifestyles among staff, few are presently willing to seek advice from the workplace regarding these issues. Promotion of healthy lifestyles in Australian workplaces is a potentially important public health advance that could reduce the incidence of diseases associated with high-risk lifestyle behaviours.

Adolescent↗
PubMed1996

[Not Available].

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History, 20th Century↗
PubMed1991

Expression of alternative isoforms of the neural cell adhesion molecule (NCAM) on normal brain and a variety of brain tumours.

A panel of monoclonal antibodies, including a reagent designated ERIC-1, have been characterized as binding to the human neural cell adhesion molecule (NCAM). These monoclonal antibodies bind in a relatively uniform manner to a variety of normal and neoplastic tissues arising from the neuroectoderm. However, multiple forms of the protein are known to arise from the differential splicing of exons within the NCAM gene located on chromosome 11 at q23. On human adult brain, four isoforms of 180, 170, 145 and 120 kDa have been identified. Here, we report the identification of another NCAM isoform of 95 kDa that is apparent on tissues following either N-glycanase or neuraminidase treatment to remove carbohydrate and sialic acid residues from the molecule respectively. NCAM expression is further complicated by differential post-translational modification of the molecule which is developmentally regulated. In general, fetal NCAM is more heavily polysialylated than the adult forms of the molecule. Human fetal brain has been shown to express the heavily sialylated embryonic form of NCAM, but following neuraminidase digestion, a similar pattern of NCAM expression is seen to that in adult brain. A variety of human brain tumours examined also show different patterns of NCAM expression, despite their uniform staining with monoclonal antibodies. The significance of these observations for designing new molecular and immunological approaches to the diagnosis of a variety of primary tumours is reviewed.

Adult↗
PubMed1989

Monoclonal antibody UJ13A recognizes the neural cell adhesion molecule (NCAM).

Monoclonal antibody (MAb) UJ13A, raised against 16-week-old human foetal brain, recognizes an antigen present on the majority of tissues of neuro-ectodermal origin. The binding profile of this antibody is similar to the known distribution of the neural cell adhesion molecule (NCAM). Although detailed immunohistological and immuno-cytochemical studies with the MAb have been published previously, we demonstrate here, through investigations of selected tissues and cell lines, that the binding profile of an anti-NCAM antiserum is similar to UJ13A. Additional indirect evidence suggesting that UJ13A recognizes NCAM comes from Northern blot analysis of cell lines either binding or not binding UJ13A as determined by indirect immunofluorescence. Only those cell lines known to bind UJ13A express high levels of NCAM mRNA. Western blot analysis of extracts of human brain show that UJ13A recognizes proteins of 180 and 140 kDa in addition to a very weak band of 120 kDa. This data corroborates the suggestion that UJ13A recognizes NCAM as these 3 isoforms of the protein are identified in human brain. Final confirmation of the specificity of UJ13A comes from the study of 3T3 fibroblasts transfected with a cDNA coding for the 125 kDa isoform of human muscle NCAM. UJ13A selectively recognizes these transfectants and binds to a 125 kDa protein isolated from the cells by Western blot analysis. Thus we conclude from these immunological, biochemical and molecular studies that the antigen recognized by the UJ13A MAb is the neural cell adhesion molecule.

Antibodies, Monoclonal↗
PubMed1989

Perinatal death.

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Adult↗
PubMed1989

Monoclonal antibodies M340 and UJ181.4 recognize antigens associated with primitive neuroectodermal tumours/tissues.

Monoclonal antibodies UJ181.4 and M340 were raised from separate fusions using either human foetal brain or medulloblastoma tissue as immunogens. The antibodies are both of IgG isotype and bind to their target antigens with affinities in excess of 10(-9) M. Both monoclonal antibodies have been shown to bind to primitive neuroectodermal tumours and human foetal brain. Expression of the two antigens is developmentally regulated as no binding is detected on adult brain as determined by a variety of indirect binding assays. The two monoclonal antibodies can be clearly distinguished by their migration in a pH gradient (isoelectric focussing gels). UJ181.4 and M340 clearly recognize two different epitopes, as it is not possible to block the binding of one antibody with an excess of the other. In addition, careful study of the binding profiles of the two reagents suggest that they recognize two distinct antigens, although these have not been biochemically characterized. The reagents have proved particularly useful in both the differential diagnosis of the small round cell tumours of childhood and anaplastic brain tumours. In addition, they have formed part of a panel of reagents used for the immunomagnetic depletion of neuroblasts from bone marrow and have been used for targeting radionuclides to tumour cells in the intrathecal compartment.

Animals↗
PubMed1985

The role of monoclonal antibodies in brain tumour diagnosis and cerebrospinal fluid (CSF) cytology.

This paper reviews the diagnostic role of monoclonal antibody immunohistochemistry in a series of 189 brain tumour biopsies and 22 cases of neoplastic meningitis. The diagnostic monoclonal antibody panel, which includes markers for glial, neural, epithelial and lymphoid differentiation antigens, was used to test a wide variety of cerebral and spinal tumours by indirect immunofluorescence and immunoperoxidase techniques on unfixed frozen sections. Gliomas, meningiomas, schwannomas, medulloblastomas, choroid plexus tumours, cerebral lymphomas and metastatic carcinomas could all be reliably differentiated by means of their characteristic antigenics profiles, as defined by their patterns of reactivity with the antibody panel. Confident diagnosis was possible even in very poorly differentiated tumours and in biopsies distorted by surgical squeeze artefact, where paucity of morphological clues made diagnosis by conventional histological methods difficult or impossible. It was estimated that use of the antibody panel was responsible for, or made a significant contribution towards the final diagnosis in approximately 20% of cases. The monoclonal reagents were also found to be of great value in the detection and characterisation of neoplastic cells in CSF specimens from patients with malignant meningitis. Malignant cells were detected in 73% of cases and characterised in 16% of cases by routine cytological techniques. Employing monoclonal immunocytology however, these figures were improved to 95% and 95% respectively. Our findings suggest that patients with neoplastic meningitis can be spared prolonged investigation and inappropriate management by the early detection and characterisation of malignant cells in CSF using panels of monoclonal antibodies.

Antibodies, Monoclonal↗