Accuracy of real-time ultrasound measurements of total tissue, fat, and muscle depths at different measuring sites in lamb.

Accuracy of live ultrasound measurements to evaluate the total tissue depth (GR), as well as fat and LM depths at different scanning sites, was studied in 96 purebred Suffolk and Dorset lambs of both sexes slaughtered between 36 and 54 kg of BW. Before slaughter, 7 real-time ultrasound measurements were taken on lambs: fat and LM depths between the 12th and 13th ribs (transverse) and between the 3rd and 4th lumbar vertebrae (transverse and longitudinal), and GR. After slaughter, the measurements equivalent to ultrasound measurements were taken on digitized images of the cuts on the left half carcass of each lamb. Ultrasound GR and fat depth measurements were closely correlated with the corresponding carcass measurements (0.76 < or = r < or = 0.81). Ultrasound GR measurement exhibited a large error of central tendency, but the level of error due to the disturbance (ED) was comparable with fat depth measurements (ED = 8.5%; residual SD = 2.24 mm; CV of residuals = 9.5%). Ultrasound fat depth measurements were more accurate between the 12th and 13th ribs (error due to regression = 1.20; ED = 0.82) than between the 3rd and 4th lumbar vertebrae (error due to regression = 5.58 and 5.4; ED = 1.10 and 0.93, transverse and longitudinal, respectively), mainly due to image interpretation errors in the lumbar region. Measurements of LM depth demonstrated low variability in the population under study (SD = 2.6 mm), and these ultrasound measurements showed low correlation with the corresponding carcass measurements (0.34 < or = r < or = 0.43). The results of this study demonstrated that ultrasound measurements were more accurate for evaluating fat depth and the GR measurements than for estimating LM depths. Ultrasound GR measurement is a promising measurement, especially where carcass grading systems are based on this carcass measurement.

The use of dual-energy X-ray absorptiometry to estimate the dissected composition of lamb carcasses.

A total of 140 male and female Dorset and Suffolk lambs were slaughtered according to four live weight classes (36-39kg, 41-44kg, 46-49kg and 51-54kg). Total tissue, fat and lean masses, and bone mineral content measured by dual-energy X-ray absorptiometry (DXA) were used to predict dissected tissue weights. The DXA total weights accurately predict half-carcasses and primal cuts weights (shoulder, leg, loin and flank) (R(2)>0.99, CVe<1.3%). The prediction of the half-carcass dissected fat percentage is weaker (R(2)=0.77, CVe=10.4%). Fatness prediction accuracy is equivalent for the shoulder, leg and loin (R(2) between 0.68 and 0.78, CVe between 10% and 13%). The R(2) obtained when predicting dissected lean content from DXA variables is 0.93 for the half-carcass and higher than 0.83 for all cuts other than flank (CVe are between 3.5% and 6.5%, except for the flank, which is 9.1%). The prediction of bone weight using the bone mineral content is not very accurate for the half-carcass, shoulder and leg (R(2): 0.48, 0.47 and 0.43; CVe: 10.2%, 12.0% and 11.6%, respectively). The situation improves, however, for the loin (R(2)=0.70, CVe=10.7%). In conclusion, DXA is an effective technology for predicting total weight and the amount of lean and fat in lamb carcasses and their primal cuts.

Standards and guidelines for performing central dual-energy x-ray absorptiometry in premenopausal women, men, and children.

The Canadian Panel of the International Society for Clinical Densitometry has developed standards in order to establish the minimum level of acceptable performance for the practice of bone densitometry in Canada. Previously, this group addressed the performance of densitometry in postmenopausal women. This report addresses the use of densitometry in men, premenopausal women, and children with a focus on dual-energy X-ray absorptiometry.

Parkinsonism in Ontario: physician utilization.

BACKGROUND: Patients with Parkinsonism have a progressive disorder requiring substantial expertise to manage effectively. METHODS: Over a six-year period we evaluated physician utilization and related costs for a large, unselected cohort of 15,304 Parkinsonian patients from the general population, comparing them to 30,608 age- and sex-matched controls within a universal health care system in Ontario, Canada. RESULTS: On average, 45% of Parkinsonian patients saw neurologists annually. The cumulative rate of at least one neurological consultation was only 59.5% over the six years. Patients aged < 65 had a much greater likelihood of consulting a neurologist (73.3%) compared to those > or = 65 (37.2%). Most Parkinsonian patients (97.2%), regardless of age, saw family physicians/general practitioners each year; 50.4% saw internal medicine consultants. CONCLUSIONS: Parkinsonian patients had increased likelihood of utilizing neurologists, primary care physicians and internists compared to controls; related costs of physicians' services were higher. Further research is necessary to evaluate differences in outcomes and costs between neurologists and other physician service providers.

Parkinsonism in Ontario: increased mortality compared with controls in a large cohort study.

BACKGROUND: PD was associated with increased mortality before levodopa therapy became available. There have been conflicting reports of PD mortality in the modern era. OBJECTIVE: To assess current mortality rates in a large unselected population receiving treatment for parkinsonism (PKM) followed for up to 6 years. METHODS: Cases were identified using linked administrative databases, including physician service and prescription drug claims, generated in Ontario's universal health insurance system. Control subjects were identified from the provincial registry of citizens and age and sex matched to cases. Comparative mortality was evaluated over the 6-year period of the study (1993/94 to 1998/99). The sensitivity of the findings was tested with differing case definitions. RESULTS: In 1993, 15,304 patients with PKM were identified and were age and sex matched to 30,608 control subjects (1:2 ratio). Over the study period, 50.8% (7,779) of the cases with PKM died compared with 29.1% (8,899) of the control subjects. The cases with PKM had an overall mortality odds ratio of 2.5 (95% CI: 2.4, 2.6) compared with the control group. Results were consistent whether cases were defined by physician diagnosis, use of anti-PD drugs, or both criteria. CONCLUSION: Despite modern drug therapy, PKM continues to confer a sharply increased mortality on unselected patients followed for several years.

Relation between hospital surgical volume and outcome for pancreatic resection for neoplasm in a publicly funded health care system.

BACKGROUND: Recent studies from the United States have shown that institutions with higher numbers of pancreatic resection procedures for neoplasm have lower mortality rates associated with this procedure. However, minimal work has been done to assess whether the results of similar volume-outcome studies within a publicly financed health care system would differ from those obtained in a mixed public-private health care system. METHODS: A population-based retrospective analysis was used to examine pancreatic resection for neoplasm in Ontario for the period 1988/89 to 1994/95. Outcomes examined included in-hospital case fatality rate and mean length of stay in hospital. For each hospital, total procedure volume for the study period was defined as low (fewer than 22), medium (22-42) or high (more than 42). Regression models were used to measure volume-outcome relations. RESULTS: The likelihood of postoperative death was higher in low-volume and medium-volume centres than in high-volume centres (odds ratio 5.1 and 4.5 respectively; p < 0.01 for both). Mean length of stay was greater in low- and medium-volume centres than in high-volume centres (by 7.7 and 9.2 days respectively, p < 0.01 for both). INTERPRETATION: This study adds to growing evidence that, for pancreatic resection for neoplasm, patients may have better outcomes if they are treated in high-volume hospitals rather than low-volume hospitals.

Patterns of practice among older physicians in Ontario.

BACKGROUND: Policy-makers interested in the supply of doctors in Canada have recently begun focusing attention on older physicians. This study informs the policy debate by analysing the practice patterns of Ontario physicians aged 65 years and over. METHODS: A cross-sectional and longitudinal analysis of physician claims data for fiscal years 1989/90 through 1995/96 was conducted. The number of full-time equivalent (FTE) physicians by age category, urban or rural status, and specialty was calculated by means of an established method, and differences between older physicians, established physicians and recent graduates (in practice for 5 years or less), in terms of the types of services provided and patients seen, were examined. RESULTS: The proportion of FTE physicians aged 65 or more increased from 5.3% to 7.0% during the study period, whereas the proportion of recent graduates decreased from 19.6% to 16.3%. Of the older physicians, 61.4% practised part time (less than 1 FTE). Half of the physicians aged 75 in 1989/90 were still in practice 6 years later. Older physicians were less likely than those under age 65 to practice obstetrics (4.6% v. 16.9%), provide emergency department services (1.1% v. 14.8%) or house calls (38.7% v. 60.4%), or perform many minor procedures (38.7% v. 62.3%) (p < or = 0.001 for all comparisons). Older physicians tended to be male and had older patients in their practices than did younger physicians. Rural regions had higher proportions of older specialists. INTERPRETATION: Ontario's physician corps is aging. This may result in decreasing availability of obstetrics and emergency department coverage in the future. Encouraging retirement may create more openings for recent graduates, but if such policies are enacted, special attention should be paid to ensure that rural communities and older patients continue to be served.

Groundwater contamination by nitrates associated with intensive potato culture in Québec.

In rural areas, groundwater contamination by nitrates is a problem related to the spreading of organic and chemical fertilizers by farmers and, to some extent, to effluents from domestic sewage systems. Health effects of groundwater contamination by nitrates have been assessed several times and may lead to important consequences for infants. Following pressures from citizens in 1990, a survey of well water quality around potato fields of the Portneuf county (Québec) found that nitrate contamination was frequently above the 10 mg-N/1 standard. Because this first survey was limited to areas of intensive potato culture, it was not possible to evaluate the real impact on the groundwater quality for the whole county and the subsequent public health intervention was spread over the entire region. A second survey was carried out in 1995 to reevaluate the situation using random sampling methods. This latter study took into account drinking water habits of the population, the relative importance of potato culture as a source of nitrogen loading, the effects of soil types, and waste-water disposal systems as well as land use on nitrate concentration in private well water. The data analysis was carried out by combining GIS and statistical methods to test hypotheses about the spatial relationship linking measured nitrate concentrations with their immediate environment. This paper presents the major findings from this second study which confirm the impact of intensive potato culture on groundwater nitrate concentrations, mainly localized in sandy soil areas within 2 km of fields. Finally, it illustrates the usefulness of GIS to focus public health interventions.

High-billing general practitioners and family physicians in Ontario: how do they do it? An analysis of practice patterns of GP/FPs with annual billings over $400,000.

BACKGROUND: To better understand the reasons why some fee-for-service physicians have high billing levels, the authors compared the practice and demographic characteristics of general practitioners and family physicians (GP/FPs) who submitted over $400,000 in annual Ontario Health Insurance Plan (OHIP) fee-for-service claims in 1994-95 with those of GP/FPs who billed between $35,000 and $400,000. METHODS: The authors describe the OHIP billing and physician characteristic data for fiscal year 1994-95. They used multivariate logistic regression to determine factors independently associated with high billing status. RESULTS: A total of 219 GP/FPs (2.5% of the GP/FPs in Ontario) billed over $400,000 in 1994-95. Of these, 14 had billing patterns similar to those of specialists, and 27 billed predominantly for diagnostic and therapeutic procedures (particularly physiotherapy). The remaining 178 (81.3%) billed for a mix of services similar to that of other GP/FPs but on average had 2.6 times the volume of patient assessments and a greater share of their total billings derived from diagnostic and therapeutic procedures (9.1% v. 5.6%). Multivariate analysis indicated that these high-volume GP/FPs were less likely than GP/FPs who billed between $35,000 and $400,000 to be 60 years of age or older (odds ratio [OR] 0.09, p < 0.05) and female (OR 0.21) and were more likely to be foreign graduates (OR 1.85) and practising in a region with low physician supply (OR 0.45 for each increase of 1 physician per 1000 population). Metropolitan Toronto was an outlier to the latter relation and was more likely to have high-volume GP/FPs (OR 16.89). INTERPRETATION: High-billing GP/FPs attained their high billing levels by maintaining large numbers of patient visits and by performing procedures. Further research is needed to determine the time spent per patient and the quality of care delivered by these physicians as well as the appropriateness of the procedures that they perform.

Fee code creep among general practitioners and family physicians in Ontario: why does the ratio of intermediate to minor assessments keep climbing?

BACKGROUND: "Fee code creep" is the increasing tendency of primary care physicians in Ontario to bill for more intermediate than minor assessments over time. The authors examine the extent and nature of fee code creep and describe physician characteristics associated with the changes. METHODS: A cross-sectional and longitudinal analysis of Ontario Health Insurance Plan billing and physician characteristic data was conducted for fee-for-service general practitioners and family physicians (GP/FPs) in Ontario. The ratio of intermediate to minor assessments (I-M ratio) was determined for the period 1978-79 to 1994-95, and the relation of various physician characteristics to high ratios was tested with bivariate and multivariate analysis. RESULTS: The I-M ratio rose 10-fold, from 0.3 in 1978-79 to 2.9 in 1994-95. Although the I-M ratio was higher for older patients and young children, changes in population age profile over time did not account for any of the increase. The median ratio varied widely among groups of physicians: urban physicians had higher ratios than rural ones (3.9 v. 3.0, p < 0.05), and recent graduates had higher ratios than physicians 60 years of age or older (5.1 v. 2.9, p < 0.05). The I-M ratio was inversely related to number of visits; physicians billing for fewer than 5000 visits had a median ratio of 4.2, whereas those billing for 20,000 visits or more had a median ratio of 1.6. INTERPRETATION: Fee code creep has contributed to expenditure growth in Ontario. This phenomenon was related to both an increase in I-M ratio over time among physicians practising throughout the study period and an influx of new physicians billing at a higher ratio. Creep was not the result of aging of the population.

A prospective quantitative study of sensory deficits after whole sural nerve biopsies in diabetic and nondiabetic patients. Surgical approach and the role of collateral sprouting.

BACKGROUND: Sural nerve biopsy (Sbx) has been employed for the diagnosis of peripheral neuropathies and for multicenter trials of therapy in diabetic neuropathy. There is only limited prospective information available about what factors influence the resolution of the sensory deficit (Sdef) after biopsy. METHODS: We prospectively studied the surface area of skin Sdef after whole human Sbx in diabetic and nondiabetic patients for up to 18 months after the procedure. Sdef was determined by mapping, in two dimensions, the area of loss to pinprick and light touch in the sural distribution using a transparent boot-like device with 1-square-cm grid markings. At the same time, patients were interviewed about biopsy-related symptoms. RESULTS: Overall, the Sdef in all patients declined by an average of 91 +/- 3% at 18 months. The pattern of Sdef decline indicated that collateral sprouting was the mechanism of sensory reinnervation. The extent of Sdef at 6, 12, or 18 months did not differ between diabetics and nondiabetics. In diabetics, there was a correlation between sensory reinnervation with pre-biopsy sural nerve potential amplitude and HbA1C level, but not with age or diabetes duration. Diabetic patients who had nerve resections starting at or below the center of a plane through the lateral malleolus and traveling proximally for 7 cm or less had a Sdef that was less than patients with longer and more proximal nerve resections. The majority of patients had unpleasant but mild mechanically elicited sensory symptoms at 1 year that had improved in most, but not all patients, by 18 months. CONCLUSIONS: Sbx is associated with prolonged sensory symptoms and sensory loss. Recovery occurs by collateral reinnervation.

Local human sural nerve blood flow in diabetic and other polyneuropathies.

Microangiopathy is considered relevant to the pathogenesis of several forms of peripheral nerve disease, particularly diabetic polyneuropathy. In diabetes, however, it is uncertain whether reductions in mixed nerve trunk blood flow account for early features of polyneuropathy in contrast to later disease, where microvascular changes have been described. To address this issue, we measured local sural nerve blood flow in patients with mild diabetic polyneuropathy who were enrolled in a clinical trial (n = 26), patients with other polyneuropathies being studied by diagnostic sural nerve biopsy (n = 17), patients with vasculitic polyneuropathy (n = 3) and one patient with rapidly progressive severe diabetic polyneuropathy and lumbosacral plexopathies. Standardized measurements were made at 10 sites along the sural nerve of each patient prior to sural nerve resection for biopsy. We used a laser Doppler flowmetry probe sensitive to red blood cell flux to measure sural nerve blood flow. This was slightly higher in patients with mild diabetes compared with those with other polyneuropathies, but was reduced in patients with vasculitis. In patients with mild diabetes, there was no relationship between sural nerve blood flow and prebiopsy sural nerve action-potential amplitude, sural myelinated fibre density, haemoglobin A1C, duration of diabetes or age of the patient. Ten diabetic patients entered in the clinical trial had sural nerve blood flow recorded in one sural nerve, followed 1 year later by a second sural nerve blood flow measurement prior to biopsy of the contralateral sural nerve. Despite a mild trend toward decline in fibre density between the nerves over this period of time, sural nerve blood flow was similar. The patient with severe diabetic polyneuropathy and lumbosacral plexopathies had reduced sural nerve blood flow. Our findings do not provide evidence that reductions in sural nerve blood flow are associated with early peripheral neuropathy in diabetes, unlike vasculitis. The early trend toward slight rises in sural nerve blood flow may be a result of early functional microangiopathy that accompanies nerve dysfunction but does not cause it.

Peptides and neuromas: calcitonin gene-related peptide, substance P, and mast cells in a mechanosensitive human sural neuroma.

We examined and compared a mechanosensitive human sural neuroma and a contralateral sural nerve collected simultaneously from a patient involved in a diabetic neuropathy research protocol. Using indirect immunofluorescence staining. we identified a striking difference in the content within axons of two neuropeptides, substance P (SP) and calcitonin, gene-related peptide (CGRP), between the contralateral nerve and the neuroma. Unlike the contralateral nerve, where immunofluorescence was sparse, a significant number of disorganized axon profiles that stained brightly positive for CGRP or SP were identified in the neuroma. In contrast, staining for tyrosine hydroxylase, a label of sympathetic axons, was largely absent except around one large arteriole. The neuroma specimen also contained large numbers of serotonin-containing mast cells, only noted occasionally in the contralateral nerve. The peptide staining and mast cell accumulation in the human neuroma closely resembled changes we have previously observed in an animal neuroma model. Local neuropeptides may play a role in the injury response of peripheral nerve, and may be related to mechanosensitivity.

Has laparoscopic cholecystectomy changed patterns of practice and patient outcome in Ontario?

OBJECTIVE: To examine the effect of the introduction of laparoscopic cholecystectomy (LC) on patterns of practice (number of cholecystectomy procedures, case-mix and length of hospital stay) and patient outcomes in Ontario. DESIGN: Cross-sectional population-based time trends using hospital discharge data. SETTING: All acute care hospitals in Ontario where cholecystectomy was provided. PATIENTS: All 119,821 Ontario residents who underwent cholecystectomy between 1989-90 and 1993-94. After exclusions (initial bile duct exploration, cancer, incidental cholecystectomy, or missing codes for age, sex or residence) 108,442 patients remained. OUTCOME MEASURES: Number of cholecystectomy procedures, proportion of patients with acute or chronic gallstone disease, length of hospital stay, and rates of death, readmission, and bile duct injury and other in-hospital complications after cholecystectomy by year. RESULTS: The number of cholecystectomy procedures increased by 30.4% between 1989-90 and 1993-94. The number of patients with chronic gallstone disease increased by 33.6%, and the number who underwent elective surgery increased by 48.3%. The proportion of procedures performed as LC increased from 1.0% in 1990-91 to 85.6% in 1993-94. Patients who received LC tended to be younger female patients with chronic gallstone disease with no coexisting conditions undergoing elective operations. The mean length of stay, adjusted for case-mix differences, was significantly lower in 1993-94 than in 1989-90 (2.6 days v. 7.5 days) (p < 0.05); the values for LC and open cholecystectomy in 1993-94 were 1.8 days and 7.3 days respectively. The decrease in the crude death rate over the study period (0.3% to 0.2%) was not significant (relative odds 1.10, 95% confidence interval [CI] 0.72 to 1.69). In 1993-94 the adjusted risk of readmission to hospital within 30 days was 1.38 (95% CI 1.19 to 1.58) as compared with 1989-90. Over the 5 years the rate of bile duct injuries tripled (0.3% in 1989-90 v. 0.9% in 1993-94). The adjusted risk of having at least one complication after cholecystectomy in 1993-94 was 1.90 (95% CI 1.75 to 2.07) as compared with 1989-90. CONCLUSIONS: LC has had a substantial effect on the number of cholecystectomy procedures performed, the type of patient having the gallbladder removed and the length of hospital stay. Death rates are unchanged, but the odds of readmission and in-hospital complications are both increased. Future research should be directed toward determining the reasons for the overall increase in rates, developing methods to reduce bile duct injuries and identifying other relevant outcomes, such as patient satisfaction with the procedure.

Analysis of diethyltoluamide (DEET) following intentional oral ingestion of Muscol.

N,N-Diethyl-m-toluamide (DEET) is an effective component of several insect repellent products. A 19-year-old woman was admitted to the emergency department following ingestion of 15-25 mL 95% diethyltoluamide (Muscol). Serum and urine toxicology screening tests were negative except for detection of DEET. DEET was qualitatively identified and quantitated by gas chromatography-mass spectrometry. Concentrations of DEET based on selected ion monitoring (ion at m/z 119) were 63.0, 17.2, 1.9, and less than 0.2 mg/L in serum specimens collected at 2, 5, 24, and 48 h following ingestion, respectively. Serial monitoring of DEET concentrations and the cardiac abnormalities observed in this case following oral ingestion were not reported previously.