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Biomedical subjects

D Paterson

Publications and source records attributed to D Paterson.

At least 19 recordsLinked to original sources

Front-line police officers' practices, perceptions and attitudes about the enforcement of impaired driving laws in Canada.

A survey of front line police officers' practices, perceptions and attitudes regarding detection of impaired driving, processing of driving while impaired (DWI) charges, criminal court proceedings and DWI sanctions was conducted across Canada. A sample of 1545 officers of all jurisdictions across the country, representative of different types of police services (i.e. national, provincial, municipal) and types of policing (i.e. traffic, general duty) were surveyed by mail. The results, based on a 71% response rate, indicate that: an average of 7.5 charges/year are laid by officers resulting mainly from erratic driving; videotaping and mobile breath testing could improve efficiency of DWI enforcement; it takes an average of 2 h 48 min to process each DWI charge; about 2/3 of officers say plea bargaining occurs at least sometimes; the average length of DWI trial is over 4 h; less than half of officers think Crown Attorneys are adequately prepared for DWI cases; about 3/4 of officers think the accused escapes conviction on a legal technicality at least sometimes; about 30% of officers say short-term licence suspensions and other forms of discretion are used at least sometimes; DWI places fifth in priority among 15 offences, up from eighth in a 1981 survey; DWI is a priority for most police management but human resources are not adequate; and there is greater support for administrative than for Criminal Code changes. Multiple regressions indicated that the number of DWI charges laid by officers depended mainly on the officers' personal priority regarding DWI enforcement. The results suggest that many officers want to enforce DWI laws but that the numerous procedural and legal barriers that they confront often force them to exercise discretion in the laying of DWI charges.

Accidents, Traffic

Vertebral osteomyelitis due to Pseudallescheria boydii.

A case of primary vertebral osteomyelitis due to an opportunistic fungus, Pseudallescheria boydii, in a child with acute myeloid leukemia, is reported. To our knowledge this is the first such case in a child, and only the second reported case in the international literature of primary spinal osteomyelitis due to this organism. We discuss the problems presented by this case both in terms of diagnosis and management. We also discuss the role of surgery and systemic antifungal chemotherapy in the treatment of deep infections due to Pseudallescheria boydii.

Child, Preschool

Bacteremia caused by a recently described novel Desulfovibrio species.

An obligately anaerobic, fastidious, slowly growing, spiral, gram-negative bacterium was isolated from the blood of a 75-year-old man with acute onset of pyrexia. The patient responded rapidly to appropriate antibiotic therapy. Extensive investigation failed to detect a focus for the infection. Phenotypically, the organism was consistent with Desulfovibrio species. Microscopic investigation revealed an organism with a vibrioid or spirillioid morphology with rapidly progressive motility by means of a single polar flagellum. Biochemically, the organism produced large amounts of H2S and contained desulfovirdin. The 16S rRNA gene sequence of the organism was found to be most similar to those of members of the genus Desulfovibrio, with identical sequence homology to the newly proposed species described by Tee et al. (W. Tee, M. Dyall-Smith, W. Woods, and D. Eisen, J. Clin. Microbiol. 34:1760-1764, 1996). This is a second unrelated isolation of this novel species from two widely different locations in Australia. The two isolates show some phenotypic differences, indicating that they are different strains of the same species.

Aged

Secure placement of peritoneal dialysis catheters using a laparoscopic technique.

Nineteen patients underwent laparoscopic placement of a peritoneal dialysis catheter with suture fixation into the pelvis. Operating time ranged from 20 to 60 min (median, 33), and the median postoperative stay for patients admitted solely for catheter placement was 1 day. No significant morbidity was associated with this procedure, and all but one catheter functioned well over the long term. Suture fixation of laparoscopically placed peritoneal dialysis catheters is straightforward, and may achieve better catheter function.

Catheterization

A study to validate the modified Canadian Aerobic Fitness Test.

This study evaluated the predictive ability of the modified Canadian Aerobic Fitness Test (mCAFT) on an independent sample of subjects and compared it to the original Canadian Aerobic Fitness Test (CAFT). Male and female subjects (n = 154), 15-69 yrs of age, performed the mCAFT and a maximal treadmill test. VO2max scores predicted from the mCAFT equation did not differ significantly from those measured during the treadmill test, whether the sample was analysed overall or categorized by sex, whereas the CAFT (Jetté) equation resulted in VO2max scores that were significantly lower than either the measured values or those predicted using the mCAFT. The strength of the linear relationship between predicted and measured VO2max scores is the same for both the mCAFT (r = 0.88) and CAFT (r = 0.89). However, the mCAFT results in a lower mean square error (37.0 for mCAFT vs. 63.3 for CAFT) and thus is an improvement over the CAFT prediction.

Adolescent

Colour Doppler studies of axillary node metastases in breast carcinoma.

Colour Doppler scans were carried out on 80 patients with breast carcinoma. Both the tumour and the lower axilla were scanned in all 80 patients. Seventy-five patients subsequently underwent axillary lymph node dissection and histological examination. The sensitivity of colour Doppler scanning for axillary node involvement was 70%, with a specificity of 98% and a positive predictive value of 96%.

Adult

Specimen-orientated radiography helps define excision margins of malignant lesions detected by breast screening.

Eighty patients with impalpable breast lesions detected by mammographic screening underwent hookwire-guided wide local excision. Excision specimens were orientated with Ligaclips and submitted to radiography; if, on the specimen radiograph, the mammographic lesion crossed any visible margin, further tissue was excised. Clear histological margins were obtained on the initial excision in 52 (68 per cent) of 77 carcinomas. After inspection of the orientated specimen radiograph, further tissue was excised from 22 patients; this significantly increased the rate of complete excision to 86 per cent (P < 0.01). Significantly more patients with invasive cancer had a complete excision than those with ductal carcinoma in situ (52 of 57 versus 14 of 20, P < 0.02).

Breast

Expression and dynamic modulation of the human granulocyte colony-stimulating factor receptor in immature and differentiated myeloid cells.

In this study we have examined the expression and modulation of the human granulocyte colony-stimulating factor (G-CSF) receptor (R) in immature and differentiated myeloid cells using a 125I labelled human G-CSF analogue (TG50). Equilibrium binding data revealed a single affinity class of receptor on all cell types expressing G-CSFR (KD 235-606 pM) with neutrophils expressing 2883 +/- 672 Rs/cell. Rapid internalization of surface receptor-bound ligand at 37 degrees C was detected in both immature cells (U937) and neutrophils with > 70% of specifically bound ligand internalized within 5 min. Concentration-response data showed that the level of occupancy of neutrophil G-CSFRs by ligand at 37 degrees C was approximately 5-fold greater than predicted by equilibrium binding data and correlated closely with concentration-response data for biological activity. Re-expression of G-CSFRs following down-regulation by internalization was not detected. Down-regulation of the neutrophil G-CSFR by several agents including granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor (TNF), lipopolysaccharide (LPS), f-met-leu-phe (fMLP), phorbol ester (TPA) and C5a was observed at 37 degrees C but not at 4 degrees C. In contrast, G-CSFRs on immature myeloid cells were significantly down-regulated by TPA only. Differentiation of myeloid leukaemic cell line HL-60 with DMSO, a frequently used model of granulocytic differentiation, was associated with a significant reduction in G-CSFR expression (11 +/- 5% of control) whereas treatment with retinoic acid led to increased G-CSFR expression (161 +/- 3%).

Binding, Competitive

Colour Doppler ultrasonography studies of benign and malignant breast lesions.

Colour Doppler scanning was carried out on 53 patients with solid, discrete breast masses. Twenty-five of 32 breast cancers and none of 21 benign lesions gave a positive scan, giving a sensitivity of 78 per cent for association with malignancy, a specificity of 100 per cent and a positive predictive value of 100 per cent. Tumours less than 1 cm in diameter and invasive lobular cancers were least likely to give a positive scan. Axillary node scans were performed in 31 of 32 patients with breast cancer with 29 undergoing an axillary staging procedure. Nine patients had a positive axillary scan and all nine had involved axillary nodes. Three patients had involved axillary nodes, but a negative axillary scan. The sensitivity of colour Doppler scanning for axillary node involvement was 75 per cent, with a specificity of 100 per cent and a positive predictive value of 100 per cent.

Adolescent

Piroxicam induced submassive necrosis of the liver.

Several widely used non-steroidal anti-inflammatory drugs have been reported as causing severe hepatitis. Three cases of severe acute hepatitis have been reported in association with piroxicam. A fatal submassive necrosis that occurred in a 68 year old lady who had received piroxicam for 15 months is described. A 48 year old man who developed submassive hepatic necrosis six weeks after beginning piroxicam but was successfully treated with orthotopic liver transplantation is also reported. Piroxicam may induce submassive necrosis of the liver, probably as an idiosyncratic reaction.

Aged

Gene expression in oestrogen-dependent human breast cancer xenograft tumours.

Xenograft tumours from an oestrogen-dependent human breast cancer cell line MCF-7 have been established and characterised in thymectomised, irradiated female CBA strain mice. There was evidence for selection in xenografts of a subpopulation of MCF-7 cells with an altered pattern of gene expression as measured by mRNA levels compared with the original cells in vitro. Tumorigenicity increased significantly on repeated animal passage but oestrogen dependence was retained. Following injection of the mice with oestrogen, mitosis was induced in the tumour cells with associated increases in thymidine uptake and percentage of cells in S-phase. In accord with these changes, c-myc and p53 expression were increased and TGF-beta was suppressed. Thereafter the expression of the c-myc and p53 genes fell whilst that of the TGF-beta gene was induced as the oestrogenic-stimulus declined. The oestrogen-regulated mRNA pS2 showed a biphasic response to oestrogen and levels declined as the serum oestrogen fell to undetectable levels. This xenograft system demonstrates that changes in transcription of oncogenes, growth factor and oestrogen-regulated genes can be detected in vivo in response to oestrogen. It thus provides an in vivo model for studies of the biochemical and molecular basis for therapeutic manipulation of hormone-sensitive human breast cancer.

Animals

Leg-lengthening procedures. A historical review.

While there are new techniques for lengthening long bones, there are, nevertheless, contraindications and preoperative considerations for lengthening the femur or tibia, such as the presence of acetabular dysplasia, fixed deformity around joints, peripheral vascular and metabolic bone disease, and the age of the patient. Lengthening a long bone may be associated with many complications, especially in a congenitally short bone. It is important to anticipate and prevent complications, especially nonunion, subluxation of joints, muscle contractures, and neurologic complications. Lengthening of the femur and tibia are not for the occasional operator. However, as Bosworth noted in 1938, attention to great detail when lengthening the bone and skilled and detailed postoperative care will allow excellent results to be obtained. Time alone will tell what, biologically, is the best method for lengthening a long bone.

Bone Lengthening