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Biomedical subjects

A H Lee

Publications and source records attributed to A H Lee.

At least 37 records · Page 2Linked to original sources
PubMed2001

Zero-inflated Poisson regression with random effects to evaluate an occupational injury prevention programme.

This study presents a zero-inflated Poisson regression model with random effects to evaluate a manual handling injury prevention strategy trialled within the cleaning services department of a 600 bed public hospital between 1992 and 1995. The hospital had been experiencing high annual rates of compensable injuries of which over 60 per cent were attributed to manual handling. The strategy employed Workplace Risk Assessment Teams (WRATS) that utilized a workplace risk identification, assessment and control approach to manual handling injury hazard reduction. The WRATS programme was an intervention trial, covering the 1988-1995 financial years. In the course of compiling injury counts, it was found that the data exhibited an excess of zeros, in the context that the majority of cleaners did not suffer any injuries. This phenomenon is typical of data encountered in the occupational health discipline. We propose a zero-inflated random effects Poisson regression model to analyse such longitudinal count data with extra zeros. The WRATS intervention and other concomitant information on individual cleaners are considered as fixed effects in the model. The results provide statistical evidence showing the value of the WRATS programme. In addition, the methods can be applied to assess the effectiveness of intervention trials on populations at high risk of manual handling injury or indeed of injury from other hazards.

Accidents, Occupational↗
PubMed2001

Sentinel node biopsy for breast cancer may have little to offer four-node-samplers. results of a prospective comparison study.

The aims of the study were to determine how often four node axillary sampling (4NAS) encompasses the sentinel node (SN) and to compare the relative sensitivity of 4NAS with sentinel node biopsy (SNB) for axillary node staging. 200 patients with breast cancer were preoperatively injected with 27 MBq 99m-Tc-labelled colloid adjacent to the tumour. At operation, standard 4NAS was performed. Each node was counted ex vivo using a probe. A search was then made to find a node with higher counts in vivo directed by the probe. If found, it was excised. Each node was submitted separately to pathology. A SN was identified in 191 patients (96%). The SN was contained in the 4NAS in 153 patients (80%) and identified separately in 38 patients (20%). Of 60 node-positive patients, 49 were positive by 4NAS and SNB, the SN was not identified in 2 and in 8 the SN was falsely negative compared with 4NAS. For 1 patient, the SN was positive and the 4NAS negative. SNB performed using radiolabelled colloid has no advantage over 4NAS when nodes are assessed by standard histological technique.

Axilla↗
PubMed2001

Determinants of maternity length of stay: a Gamma mixture risk-adjusted model.

With obstetrical delivery being the most frequent cause for hospital admissions, it is important to determine health- and patient-related characteristics affecting maternity length of stay (LOS). Although the average inpatient LOS has decreased steadily over the years, the issue of the appropriate LOS after delivery is complex and hotly debated, especially since the introduction of the mandatory minimum-stay legislation in the USA. The purpose of this paper is to identity factors associated with maternity LOS and to model variations in LOS. A Gamma mixture risk-adjusted model is proposed in order to analyze heterogeneity of maternity LOS within obstetrical Diagnosis Related Groups (DRGs). The determination of pertinent factors would benefit hospital administrators and clinicians to manage LOS and expenditures efficiently.

Diagnosis-Related Groups↗
PubMed2001

Expression of CD34 and bcl-2 in phyllodes tumours, fibroadenomas and spindle cell lesions of the breast.

AIMS: Strong expression of CD34 and bcl-2 has been described in solitary fibrous tumours. It has been proposed that these lesions arise from long-lived mesenchymal cells. We tested the hypothesis that spindle cell lesions of the breast arise from similar mesenchymal cells in the mammary stroma. METHODS AND RESULTS: Sections of phyllodes tumours (26), fibroadenomas (15), myofibroblastomas (two), pseudoangiomatous hyperplasia (five) and myoid hamartoma (one) were stained immunohistochemically for CD34 and bcl-2. Conventional mammary carcinoma is known to be CD34-negative: we therefore stained 11 spindle cell carcinomas and one adenosquamous carcinoma. The mammary stroma, particularly around lobules, stained for CD34. All the lesions (except the carcinomas) showed spindle cell staining for CD34. There was more staining in fibroadenomas than in phyllodes tumours (especially malignant tumours). The staining in phyllodes tumours was typically patchy. In some there was increased or decreased staining adjacent to the epithelium. There were occasional spindle cells positive for bcl-2 in the normal perilobular stroma. bcl-2 was frequently expressed in spindle cells in fibroadenomas, phyllodes tumours and pseudoangiomatous hyperplasia, and rarely in the other lesions. CONCLUSIONS: The combined expression of CD34 and bcl-2 suggests that fibroadenomas, phyllodes tumours and pseudoangiomatous hyperplasia may arise from long-lived bcl-2-positive mesenchymal cells in the breast in a manner similar to that proposed for solitary fibrous tumours. The absence of CD34 staining in spindle cell carcinomas is of potential diagnostic value in the distinction from malignant phyllodes tumours in difficult cases.

Antigens, CD34↗
PubMed2001

DNA analysis for the Dombrock polymorphism.

BACKGROUND: RBC typing for Do(a) and Do(b) is notoriously difficult, and inaccurate typing can predispose patients to hemolytic transfusion reactions. The DO1/DO2 polymorphism is associated with three nucleotide changes: 378 C>T, 624 T>C and 793 A>G. While the 378 C>T- and 624 T>C-containing codons are silent mutations, the 793 A>G polymorphism in codon 265 encodes asparagine for Do(a) and aspartic acid for Do(b). STUDY DESIGN AND METHODS: Described here are two PCR-RFLP assays, one using the Mnl I site associated with 624C (DO2) and the other altering two nucleotides within the sense primer, which allows recognition of 793G by the Eam 1105 I. RESULTS: The assays have been performed on over 100 samples for which the RBC typing of one or both antigens was known. Eight samples had been historically mistyped by hemagglutination. CONCLUSION: This RFLP assay provides a practical method for typing donor blood for Dombrock alleles.

Base Sequence↗
PubMed2001

Measuring resident satisfaction in residential aged care.

PURPOSE: The aims of this study were to assess the factor structure, reliability, and validity of an existing Resident Satisfaction Questionnaire (RSQ) and to develop a short-form RSQ for regular use in residential aged care settings. DESIGN AND METHODS: A cross-sectional survey design was adopted to collect the required information, with facilities being selected using stratified random sampling. Both exploratory and confirmatory factor analyses were conducted on a sample of 1,146 residents in 70 residential aged care facilities in Western Australia. RESULTS: The RSQ is confirmed to be a reliable, valid, context-relevant, and easy-to-use instrument for assessing residents' satisfaction with their residential aged care facilities. Resident satisfaction, as assessed via the RSQ, was found to be a multidimensional construct comprising six factors-Room, Home, Social Interaction, Meals Service, Staff Care, and Involvement. IMPLICATIONS: A 24-item short version of the RSQ can be constructed based on the six-factor resident satisfaction measurement model and used as a regular monitoring tool of resident satisfaction for quality improvement purposes.

Aged↗
PubMed2001

Preoperative assessment of prognostic factors in breast cancer.

The adoption of preoperative diagnostic strategies involving fine needle aspiration cytology (FNAC) or core biopsy is well established, allowing the planning of operating lists and bed occupancy and patient involvement in therapeutic management. In addition to diagnosis, however, pathologists are increasingly being asked to provide pathological prognostic information from preoperative samples. This leader describes techniques for predicting prognosis and response to treatment on these specimens and some of the problems inherent in the determination of prognosis on small samples. For example, although histological grade can be assessed relatively reliably on either core or FNAC samples, the evaluation of tumour type (which includes an overall assessment of the architecture of a given tumour) may be less reliable on small preoperative samples. Other well recognised histological prognostic factors, such as vascular channel invasion or tumour size, cannot be determined accurately on small preoperative samples. For those patients who might benefit from neoadjuvant treatment, predicting the response to such treatments--for example, by the assessment of oestrogen receptor status--can readily be performed on either core biopsy or FNAC. In the future, other molecular markers such as C-erbB-2 might also prove beneficial in predicting response to newly developed treatments.

Biomarkers, Tumor↗
PubMed2001

Consultative team to assess manual handling and reduce the risk of occupational injury.

OBJECTIVES: To describe the formation of a consultative team to assess the risk of manual handling in the workplace that started in October 1992 within the cleaning services department of a 600 bed hospital, and to evaluate the effectiveness of its recommendations in reducing the rate and severity (time lost and cost) of workers' compensation injury. METHODS: The consultative team identified, assessed, and recommended controls for manual handling and other injury risks. Data on injuries counted before and after implementation of the team's recommendations were obtained for the cleaning services study group, an orderly services comparison group, as well as cleaners from a peer hospital and for the State of Western Australia. Evaluation of the four groups was undertaken 3 years after the end of the study period, to allow maturation of the costs of the claims (adjusted to July 1998 consumer price index) and hours lost from work. RESULTS: Statistical analysis showed that implementation of the recommendations significantly reduced numbers and rates of injury, but not the severity of injury, in the cleaning services study group. There was no difference in numbers or severity of injuries for the comparison groups before and after implementation of the recommendations. CONCLUSIONS: The recommendation of the consultative team can produce a meaningful and sustained reduction in rates of injury within an at risk population. The results support a consultative approach to reducing workplace injuries from manual handling. The team process has potential for application to occupational groups at risk of exposure to other types of hazards.

Accidents, Occupational↗
PubMed2001

Assessing quality of life for adolescents in western Australia.

This study investigates the quality of life (QOL) for adolescents residing in Perth, Western Australia. The Quality of Life Profile-Adolescent Version (QOLPAV), a generic self-reported questionnaire, was administered to 363 adolescents aged between ten and 18 years who were enrolled in 20 high schools within metropolitan Perth. Stepwise regression analysis of the data showed that age, control, opportunity and perceptions of health have significant associations with QOL. It was also found that adolescents with a chronic condition and those without have similar QOL scores. This suggests that, in terms of QOL, the chronically ill adolescents do not view themselves as different from their healthy counterparts.

Adolescent↗
PubMed2001

Determining the effects of patient casemix on length of hospital stay: a proportional hazards frailty model approach.

OBJECTIVES: To identify factors associated with hospital length of stay (LOS) and to model variations in LOS within Diagnosis Related Groups (DRGs). METHODS: A proportional hazards frailty modelling approach is proposed that accounts for patient transfers and the inherent correlation of patients clustered within hospitals. The investigation is based on patient discharge data extracted for a group of obstetrical DRGs. RESULTS: Application of the frailty approach has highlighted several significant factors after adjustment for patient casemix and random hospital effects. In particular, patients admitted for childbirth with private medical insurance coverage have higher risk of prolonged hospitalization compared to public patients. CONCLUSIONS: The determination of pertinent factors provides important information to hospital management and clinicians in assessing the risk of prolonged hospitalization. The analysis also enables the comparison of inter-hospital variations across adjacent DRGs.

Delivery, Obstetric↗
PubMed2000

Tumour necrosis factor-alpha and interferon-gamma synergistically activate the RANTES promoter through nuclear factor kappaB and interferon regulatory factor 1 (IRF-1) transcription factors.

Inflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) synergistically activate expression of the RANTES (regulated upon activation, normal T-cell expressed and secreted) gene, which plays a crucial role in the chemoattraction of leukocytes during the inflammatory response. To understand at the molecular level the mechanism by which the two cytokines activate RANTES gene expression, we determined the requirement of cis-acting elements in the RANTES promoter and trans-acting factors. The murine RANTES promoter contained one putative interferon regulatory factor, IRF, and three putative nuclear factor kappaB (NF-kappaB) binding sites. Specific destruction of the IRF binding site and one of the three NF-kappaB binding sites abolished the inducibility of promoter activity by IFN-gamma and TNF-alpha, respectively. In contrast, mutation of the other two putative NF-kappaB binding sites did not affect RANTES promoter activity significantly. In addition, the RANTES promoter was stimulated by co-transfection of plasmids that expressed either p65, an NF-kappaB family protein, or the IRF-1 transcription factor. RANTES promoters with mutations in the NF-kappaB or IRF binding sites were not stimulated by p65 or IRF-1 expression, respectively. In electrophoretic mobility-shift and immunologic assays, we showed that IRF-1 was induced after cells were treated with IFN-gamma and that NF-kappaB was activated by TNF-alpha treatment. These results demonstrate that both NF-kappaB and IRF-1 transcription factors mediate the induction of RANTES expression via their cognate cis-acting elements when cells are stimulated by TNF-alpha and IFN-gamma.

3T3 Cells↗
PubMed2000

Determinants of length of stay: implications on differential funding for rural and metropolitan hospitals.

This study analysed and compared the determinants of length of inpatient stay between the rural and metropolitan public hospitals. The investigation was based on the 1998/99 Western Australia patient discharge data. A Cox regression model was used due to the high proportion of patient transfers in the rural hospitals. It was found that several variables were associated with length of stay (LOS) variations within Diagnosis Related Groups (DRG). The method provides additional insights to hospital management and clinicians in assessing the risk of prolonged hospitalisation. From a state government perspective, a DRG payment adjustment strategy may be developed for different categories of admitted patient episodes. The analysis has implications on the formulation of differential funding rates between rural and metropolitan hospitals.

Adult↗
PubMed1999

DNA inoculations with HIV-1 recombinant genomes that express cytokine genes enhance HIV-1 specific immune responses.

Vaccination with HIV-1 DNA sequences induce both humoral and cellular immune responses in experimental animals. However, these responses are relatively weak and are often only transient in their nature. In order to enhance the level of HIV-1 specific immunity, we have engineered HIV-1 DNA constructs which contained various cytokine genes such as interleukin-2 (IL-2), granulocyte-macrophage colony stimulating factor (GM-CSF) and interferon-gamma (IFN-gamma) gene. These constructs have deleted the tat and nmf genes of HIV-1 to eliminate their immunosuppressive effects. Immunizations with these recombinant constructs elicited moderate proliferative T cell responses but poor antibody responses in rats. However, inoculations of HIV-1 DNA that contained the GM-CSF or the IL-2 gene significantly enhanced humoral and proliferative T cell responses, respectively. Thus, recombinant HIV-1 genomes such as those described here may increase the efficacy of DNA vaccination.

AIDS Vaccines↗
PubMed1999

Angiogenesis and expression of thymidine phosphorylase by inflammatory and carcinoma cells in ductal carcinoma in situ of the breast.

Angiogenesis is essential for tumour growth and important in metastasis and for prognosis in invasive carcinoma of the breast. Two patterns of increased vascularity have been shown in mammary ductal carcinoma in situ (DCIS): a cuff of vessels close to the involved ducts, and vessels in the interductal stroma. Inflammation may potentially promote angiogenesis by release of angiogenic factors and digestive enzymes. A correlation has previously been found between the intensity of perivascular inflammation and stromal vascularity in DCIS, but no strong relationship has been observed between inflammation and angiogenesis in invasive carcinoma. Tumour angiogenesis is regulated by a number of angiogenic factors, including thymidine phosphorylase (platelet-derived endothelial cell growth factor), which is expressed at high levels in macrophages. Using immunohistochemical methods, thymidine phosphorylase expression and vascularity have been studied in DCIS (n = 34) and invasive carcinoma (n = 32). Stromal vascularity in DCIS was associated with thymidine phosphorylase expression in the perivascular inflammatory cells and in the cytoplasm of carcinoma cells. In invasive carcinoma, no relationship was found between vascularity and thymidine phosphorylase expression in either the carcinoma or the inflammatory cells. This study suggests that thymidine phosphorylase expression in both inflammatory and carcinoma cells may contribute to one of the patterns of vascularity in DCIS, but not in invasive disease.

Breast Neoplasms↗