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Biomedical subjects

S MacDonald

Publications and source records attributed to S MacDonald.

At least 55 records · Page 3Linked to original sources
PubMed1996

Promotion of cervical screening uptake by health visitor follow-up of women who repeatedly failed to attend.

BACKGROUND: It is important that if cervical screening programmes are to be successful coverage rates of the target population of women are high. In the context of a well-organized programme in Fife a project was carried out to assess the impact of health visitors following up women who had repeatedly failed to attend for screening. METHODS: Ten health visitors in Fife were randomly selected and were each asked to approach 20 women registered with the general practice to which they were attached who met the study criteria. Women were asked for their reasons for non-attendance. Subsequent attendance for cervical screening was identified through the on-line cervical cytology database. RESULTS: Two health visitors declined to participate in the project. One hundred and sixty-two women were offered a visit by a health visitor to discuss their reasons for non-attendance. Forty-two (28 per cent) of the women approached attended for a smear in the following three months. Of those visited by a health visitor 37 per cent attended for a smear. CONCLUSIONS: In Fife, local beliefs and attitudes about cervical screening together with lack of knowledge of existing clinics with female staff operating outside working hours constitute the major reasons for non-attendance. In this situation, a personal approach based on providing information and individual counselling appears to be successful in encouraging non-attenders to reconsider their decision and participate in the cervical screening programme.

Adult↗
PubMed1995

Haemoglobin-based blood substitutes and sepsis.

An important concern that has received little attention is the possible increased susceptibility to bacterial infections of patients infused with cell-free haemoglobin-based blood substitutes. We show that pyridoxalated polymerised human haemoglobin promotes fulminating Escherichia coli septicaemia in mice, which draws attention to the potential danger of such products in the clinic.

Animals↗
PubMed1995

Factors influencing mode of claims settlement in workers' compensation cases.

This paper examines the variables that influence the means by which 10,192 injured workers settled their compensation claims during 1990. The data on which this study is based come from a state in Australia where there are three means by which workers' compensation claims can be settled by lump sum payment: settlement following a specific injury payment, early settlement payment and settlement following a common law payment. This paper is specifically concerned with identifying the variables that determine whether the claim will be settled by a lump sum payment and whether different modes of claims settlement by lump sum are unique and predictable from a range of variables that include injury characteristics and demographics. The results of logistic regression modelling revealed that those who received a lump sum settlement could be reliably distinguished from those who did not receive such a payment. Each mode of settlement varied in the extent to which it could be predicted. Contrary to expectations, the most difficult form of settlement mode to predict was that of specific injury payments (4% accurate) with the most predictive being early settlement payments (81% accurate). Common law payments were also highly predictable (48% accurate). The form of lump sum payment received by injured workers was found to depend on a range of injury characteristics, indices of severity and for common law payments, gender and potential income loss. It is argued that although injury characteristics play a part in the process of claims settlement, personal circumstances and insurance company policies are influential in dictating the form by which workers compensation cases are finalized.

Age Factors↗
PubMed1995

Laparoscopic cardiomyotomy with a Dor patch for achalasia.

OBJECTIVE: To evaluate early experience with laparoscopic Heller's cardiomyotomy with placement of a Dor patch for achalasia. DESIGN: A prospective case series. SETTING: A university teaching hospital. PATIENTS: Fourteen patients (5 men, 9 women, median age 47 years) with esophageal achalasia, treated between July 1992 and July 1994. INTERVENTIONS: Laparoscopic Heller's cardiomyotomy with a Dor patch. MAIN OUTCOME MEASURES: Clinical relief of symptoms, confirmed by esophageal manometry, 24-hour ambulatory pH monitoring and barium-contrast radiography. RESULTS: Three of the 14 patients required conversion to an open procedure, and 1 underwent early laparotomy for postoperative bleeding. The median operating time was 120 minutes (range from 75 to 210 minutes), and the median duration of hospitalization was 4 days (range from 3 to 18 days). Normal physical activity was resumed after a median of 2 weeks (range from 0.5 to 6 weeks). Symptomatic dysphagia was completely relieved in 12 patients and improved in 2. Only one patient experienced symptoms of reflux postoperatively. Postoperative esophageal manometry (seven patients), 24-hour pH monitoring (five patients) and barium-meal radiography (seven patients) confirmed the clinical results. CONCLUSION: Laparoscopic Heller's cardiomyotomy with a Dor patch provides a viable alternative to open cardiomyotomy and forceful endoscopic dilatation.

Cardia↗
PubMed1995

Measurement of polyethylene wear in metal-backed acetabular cups. II. Clinical application.

The new 3-dimensional technique was applied to the radiographs of 141 patients who had received Porous Coated Anatomic total hip prostheses. Values were obtained for the position of the acetabular cup, the 3-dimensional distance and direction of femoral head displacement, and the minimum volume of polyethylene debris produced. Mean age of the patients at the time of replacement was 61 years old; mean followup was 5.6 years (range, 4-7.2 years). Change in the position of the femoral head between initial and long-term followup films was assumed to represent polyethylene wear, and formulas were used to calculate the minimal volume of polyethylene debris produced. The overall rate of 3-dimensional femoral head displacement was 0.264 mm per year, almost twice that usually quoted in the current literature for 2-dimensional linear wear. A significant contribution to this value was made by anterior and posterior displacement. Two-dimensional femoral head displacement (measured in the plane of anteroposterior radiographs) on the same patients was 0.149 mm per year. The mean minimum volume of polyethylene debris produced after 5.6 years was 0.448 cm3 (range, 0.00-2.83 cm3), giving a mean rate of 0.079 cm3 polyethylene debris produced each year. Thirteen patients in this series had radiologic osteolysis and a significantly greater femoral head displacement and polyethylene volumetric wear than those with no osteolysis. Patients with a 32-mm femoral head diameter and a polyethylene linear < 1 cm thick had a significantly greater amount of polyethylene wear. This series gives previously unavailable data on 3-dimensional femoral head displacement and is the first report that correlates the minimum volume of polyethylene wear produced with radiologic osteolysis.

Acetabulum↗
PubMed1995

Postdischarge surgical site infection surveillance.

OBJECTIVE: To evaluate three methods for conducting post-discharge surgical site infection (SSI) surveillance. DESIGN: Patients undergoing in-patient and day-patient surgery were prospectively randomized to one of three surveillance methods: group 1, patient questionnaire (mailed back); group 2, surgeon follow-up card; or group 3, patient questionnaire (telephoned by an infection control practitioner [ICP]). There were 200 in-patients and 200 day-patients randomized to each group. Evaluation of SSI was conducted 30 days postoperatively. SETTING: A 760-bed tertiary care teaching hospital. RESULTS: Questionnaires were sent home with 350 patients. Fifteen in-patients and 35 day-patients were excluded; 15 in-patients and 17 day-patients returned questionnaires early (fewer than three weeks postoperation), leaving 54 of 185 in-patients (29.2%) and 25 of 165 day-patients (15.2%) with timely returns. Seven (three in-patients and four day-patients) reported symptoms of SSI. Surgeons received cards for 400 patients; cards were returned for 118 of 203 in-patients (58.1%) and 142 of 197 day-patients (72.1%). Twelve (seven in-patients and five day-patients) were reported to have developed SSI. ICPS telephoned 332 patients; 187 of 196 in-patients (95.4%) and 107 of 126 day-patients (84.9%) were reached in six or fewer attempts. Four in-patients and 74 day-patients were lost due to cancellation of surgery or no surgical incision. Fourteen (10 in-patients and four day-patients) reported symptoms of SSI. For group 1 patients, ICPS spent 17 h distributing questionnaires and instructing staff; for group 2, ICPs spent no time distributing material; and for group 3, ICPS spent at least 8 h completing data forms, 16.5 h on the telephone and 33 h conducting demographic data retrieval from the hospital computer. CONCLUSIONS: In this setting, surgeon follow-up cards were the most efficient and reliable method for conducting postdischarge SSI surveillance. They provided a good rate of return and were time efficient, and wound evaluation was done by trained professionals using standard criteria for diagnosis of postoperative SSI.

Aftercare↗
PubMed1994

Neurasthenic fatigue, chemical sensitivity and GABAa receptor toxins.

Following observation of fatigue syndromes in people who have been occupationally exposed to pesticides and insecticides which exert their toxicity through the GABAa receptor, we have formulated the hypothesis that fatigue syndromes in general may be secondary to altered sensitivity of the GABAa receptor. We discuss the possible involvement of organochlorine compounds which are widespread in the environment. Organophosphate compounds may have similar toxic effects through damaged cholinergic input to the dentate gyrus of the hippocampus where cholinergic and GABAergic transmission are closely linked.

Adult↗
PubMed1994

A study of the relationship between patient dose and size in paediatric radiology.

Entrance doses and dose-area products have been measured for paediatric X-ray examinations in a dedicated paediatric department. Dose-area products for barium meal and micturating cystourethrogram examinations involving fluoroscopy were substantially less than results from other studies. A number of factors contribute to this, including a high gain image intensifier used without a grid, shorter screening times, smaller numbers of films, exclusive use of a 100 mm camera and careful collimation of the X-ray field. Entrance air kerma has been measured for pelvis, abdomen, chest and skull radiographs. The relationship between dosimetric quantities and an equivalent patient diameter derived from data on patient height and weight has been studied. The results show a linear relationship between the logarithm of entrance air kerma and equivalent patient diameter for radiographic examinations performed on a single X-ray unit. Application of exponential correction factors could allow entrance doses for radiographs of children of different ages to be compared with appropriate reference doses.

Adolescent↗
PubMed1994

Rehabilitation for convicted drinking drivers (second offenders): effects on mortality.

The mortality experience of convicted drinking drivers (second offenders) (N = 347) randomly assigned to rehabilitation and control groups in two Ontario cities was examined. Over a follow-up period ranging between 8 and 13 years, 14 (11.0%) of the controls and 17 (7.7%) of the rehabilitation group died. Direct comparisons of the randomly assigned control and treatment groups revealed a tendency for lower total mortality and significantly lower mortality from accidental and violent death in those assigned to rehabilitation. Additional comparisons involving a combined rehabilitation group (N = 487) (rehabilitation participants randomly and not randomly assigned) confirmed these observations.

Accidents, Traffic↗
PubMed1994

An outbreak of diarrhea due to verotoxin-producing Escherichia coli in the Canadian Northwest Territories.

In the summer of 1991 a large outbreak of Escherichia coli O157:H7 associated diarrhea occurred in 6 Inuit communities in the Canadian Northwest Territories. The total population of these communities is 5,292. Of the 521 individuals who developed diarrhea, 152 (29%) were positive for E. coli O157:H7 on stool culture or positive by verotoxin analysis. Median age was 6 years. The attack rate for children < 1 year was 43% in the major affected community of Arviat. Hemolytic-uremic syndrome (HUS) developed in 22 cases, and 2 patients died. Asymptomatic stool carriage of verotoxin-producing E. coli (VTEC) 2-5 weeks after diarrheal illness was noted in 4/28 persons followed prospectively. Epidemic curves, case-control studies and phage type testing suggested person-to-person transmission. The original source of infection was not identified, though a food source was suspected. VTEC were detected in 6 food samples (minced beef and caribou) taken from retail outlets and homes. Primary prevention of infection through health education and promotion activities, as well as long-term follow-up of HUS survivors, are indicated in this population.

Adolescent↗
PubMed1993

An anatomic, radiographic, and biomechanical assessment of extrapedicular screw fixation in the thoracic spine.

This study performed a thorough review of the pertinent thoracic spine anatomy to determine the appropriate landmarks for extrapedicular screw placement and indentified the anatomic structures at risk; assessed the safety and accuracy of the newly proposed screw insertion technique; determined the stability and strength of this new screw position through biomechanical testing; and analyzed the stability of this extrapedicular screw location with respect to bone mineral density of the vertebra.

Biomechanical Phenomena↗
PubMed1993

Mortality in a sample of convicted drinking drivers.

Mortality rates for 639 drinking drivers were calculated. The sample consisted of all individuals convicted of a second offence in two Ontario cities (Oshawa and North Bay) between 1973 and late 1978. There were 53 deaths (51 males, 2 females) in the sample prior to the end of 1986. Among males, significant excess total mortality was observed (Standardized Mortality Ratio = 1.7); similar trends were observed among females. Age-related excess mortality and excess mortality by cause were strikingly similar to mortality patterns observed among alcoholics.

Accidents, Traffic↗
PubMed1993

Angiotensin II stimulates growth and steroidogenesis in zona fasciculata/reticularis cells from bovine adrenal cortex via the AT1 receptor subtype.

Primary cultures of bovine adrenocortical zona fasciculata/reticularis (zfr) cells responded to angiotensin II (AII) with a dose-dependent increase in [3H]thymidine incorporation into DNA. The effect was maximal at 100 nmol/liter AII, and was dose dependently inhibited by (sar1, ala8)-AII (saralasin) and DuP753, but not by PD123177. Both AII-stimulated cortisol secretion and phosphoinositidase C activity were also inhibited by saralasin and DuP753, but not by PD123177. Pharmacological analysis of the antagonism of AII-stimulated cortisol secretion by saralasin and DuP753 produced pA2 values of 8.79 and 7.02, respectively. Whereas the pA2 for saralasin agreed closely with previous measurements in other systems, DuP753 was at least one order of magnitude less potent in inhibiting the action of AII in bovine zfr cells compared to previous measurements in rabbit vascular smooth muscle. We conclude that the steroidogenic and mitogenic effects of AII in bovine zfr cells are mediated by the AT1 receptor.

Angiotensin II↗
PubMed1993

Salivary total protein and experimental Coriolis sickness.

Symptomatic reporting has been used in quantifying the severity of motion sickness including Coriolis sickness. This study was designed to objectively examine if the dynamic changes of salivary protein concentration relate to the severity of Coriolis sickness. Healthy adults with normal vestibular function underwent a modified Coriolis Sickness Susceptibility Index (CSSI) test, utilizing a staircase profile. Salivary samples were obtained prior to stimulation, 15, 30, and 45 min following stimulus onset, and/or upon reaching "nausea-II" endpoint. Total protein concentration tended to rise over the initial 30 min of stimulation, and then level off or decline. A statistically significant difference was found between the pre-stimulation and 30 min samples. Although some variability existed among the subjects, the general pattern of changes along the time course was similar. An inverse correlation approaching statistical significance was found between control (non-stimulus) total protein levels, and minutes of Coriolis stimulation required to reach the "nausea-II" endpoint. Thus, baseline salivary total protein levels can be of use in predicting susceptibility of Coriolis sickness and other forms of motion sickness.

Adult↗
PubMed1992

Automated liquid chromatographic determination of ochratoxin A in cereals and animal products using immunoaffinity column clean-up.

The analysis of the fungal mycotoxin ochratoxin A in cereals and animal products is described using an immunoaffinity column clean-up and high-performance liquid chromatographic determination. The clean-up can be carried out manually or using a commercially available automated sample preparation system. The method has been applied to cereals such as wheat, rye and barley, unprocessed breakfast cereals and animal products such as pigs' kidneys and blood sausages. Recoveries ranged from 70-80% for spiked samples (10 micrograms/kg) and the method had a relative standard deviation of 1.3% (n = 8) for the analysis of a wheat sample naturally contaminated at 13.7 micrograms/kg ochratoxin A and relative standard deviation of 3.0% (n = 8) for a pig kidney sample spiked at 10 micrograms/kg ochratoxin A. The immunoaffinity approach was significantly faster than methods employing conventional chromatographic clean-up, and extracts were freer of co-extractives giving a limit of detection of 0.2 micrograms/kg.

Animals↗