NHS entrants. That was the year, that was. Interview by Barbara Millar.
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Career Choice↗
Biomedical subjects
M Law
Publications and source records attributed to M Law.
Having too much evidence (depression, suicide, and low serum cholesterol)
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Accidents↗
Laparoscopic discectomy with anterior interbody fusion of L5-S1.
BACKGROUND: A laparoscopic approach to the spine for the performance of a minimally invasive discectomy was first described in 1991. Since that time, a number of approaches to laparoscopic discectomy have appeared in the literature. Although these reports demonstrate the ability to approach the spine through a laparoscopic technique, they do not address the issues of loss of disc space, lumbar instability, and the need for interbody fusion. METHODS: Described is a technique of laparoscopic discectomy with interbody fusion that has been performed successfully in 75 patients. Although a carbon fiber implant was utilized to aid in the fusion process, the technique can equally be performed using donor bone as the interbody support. In the 75 patients attempted, 73 procedures were successfully completed via the laparoscopic approach. One patient was converted to an open anterior approach due to extensive pelvic adhesions from prior surgery. A second patients procedure was aborted after the diagnostic laparoscopy demonstrated dense presacral scarring from a previous gynecological procedure. RESULTS: There were no major complications in the series. Two patients with high riding bladders sustained bladder lacerations that were recognized and repaired with simple suture closure. There were no bowel injuries, and more importantly, no major vessel injury. The patients were discharged from the hospital on an average within 36 hours, with a return to work averaging between 2-4 weeks depending on the patients type of work. Using a modified pain score for evaluation, post operative pain was reduced by 75%. CONCLUSIONS: From this study, it is concluded that laparoscopic discectomy with interbody fusion is not only feasible, but appears to give good results with follow up extending out beyond two years. Issues regarding the use of carbon fiber cages vs. bone and indications of the procedure are independent of the laparoscopic approach and are addressed extensively in the orthopedic literature. It can be concluded that when there is surgical indication for L5-S1 discectomy, that a laparoscopic approach with interbody fusion may become the procedure of choice.
Diskectomy↗
Accuracy of pelvic radiotherapy: prospective analysis of 90 patients in a randomised trial of blocked versus standard radiotherapy.
The aim of this study was to assess the accuracy of pelvic radiotherapy during a trial of blocked radiotherapy at the Royal Marsden Hospital, UK. Prospective evaluation was performed on 90 patients receiving CT planned pelvic radiotherapy using weekly anterior-posterior and lateral portal films. Field placement errors (FPEs) were calculated by comparing field centres of each film with a designated point of interest. Data was evaluated to calculate the overall treatment simulator differences, the number of error free treatments, and mean treatment-simulator position and to evaluate the role of systematic versus random errors. Age, weight, disease site, position of treatment, fractionation, blocked versus conventional techniques were assessed for their effect on treatment accuracy. The mean absolute error between treatment and simulator films was anterior right-left (ARL) 0.25 cm, anterior superior-inferior (ASI) 0.32 cm, lateral anterior-posterior (LAP) 0.42 cm, and lateral superior-inferior (LSI) 0.28 cm. On average the field centre was displaced by 0.66 cm (standard deviation, S.D. = 0.34) from that intended. On each treatment day 29% of anterior films and 45% of lateral films had at least one 0.5 cm error. Overall 59% of treatments had at least one 0.5 cm error and 9% a 1.0 cm error. The field centre was more than 0.5 cm from the position intended in 66% of treatments and over 1 cm for 14% of treatments. Analysis of variance showed that both random and systematic errors occurred in all directions. Though random errors were of similar magnitude in all direction (variance sigma 2 = 0.06-0.09 cm2); systematic errors showed a 4-fold variation being greatest in the LAP direction (sigma 2 = 0.19 cm2) and least the ARL direction (sigma 2 = 0.048 cm2). No factor consistently predicted for worse outcome in all directions. Hypofractionated treatments were less accurate in the LSI direction (P > 0.05). Systematic errors were associated in the ARL direction with hypofractionation (P < 0.01) and, in the LSI direction with weight (P < 0.03) and age (P < 0.05). We conclude that significant random and systematic errors can occur during pelvic radiotherapy especially in the LAP direction. These results suggest that in the absence of a customised immobilisation device, to cover 95% of errors, margins of 0.6 cm for RL and SI directions and 0.9 cm for AP direction should be allowed between the planning and clinical target volumes. However, ideally, each centre should determine their own margin requirements according to local clinical practice.
Age Factors↗
Primary infection with zidovudine-resistant human immunodeficiency virus type 1 does not adversely affect outcome at 1 year. Sydney Primary HIV Infection Study Group.
Human immunodeficiency virus type 1 (HIV-1) variants with reduced in vitro sensitivity to zidovudine, conferred by specific mutations in the viral reverse transcriptase, emerge during prolonged therapy. Late-stage disease and declining CD4 cell count are associated with more rapid emergence of these resistant variants. Isolates of HIV-1 from seroconverters were screened for the zidovudine-resistance marker mutation at codon 215. HIV-1 with the altered genotype was detected in 5 (8.2%) of 61 patients soon after onset of symptomatic primary illness and from the sex partner of 1 patient. These transmitted resistant viruses were either replaced by strains susceptible to zidovudine within a few months of infection or persisted for up to 1 year in the absence of prolonged zidovudine therapy. The resistant genotype persisted in 3 of 5 seroconverters but in 2 patients had reverted to wild type at 48 and 52 weeks. Primary infection with zidovudine-resistant variants of HIV-1 was not associated with a more severe symptomatic primary illness or more rapid CD4 cell decline at 1 year after infection.
Acquired Immunodeficiency Syndrome↗
Magnetic repulsion of linear accelerator contaminates.
Neodymium Iron Boron (NdFeB) rare earth permanent magnets have unique properties that enable them to fit easily onto the accessory mount of a clinical linear accelerator to partially sweep away electron contamination produced by the treatment head and block trays and thus increase skin sparing. Using such magnets the central axis entrance surface dose has been reduced by 11% for a 20 x 30 cm field size from 32% to 21% of maximum dose by the magnetic device. A reduction of 14% from 32% to 18% was seen for a 20 x 20 cm field size with a 6 mm perspex block tray positioned above the magnet. The magnetic device is light weight and thus clinically usable.
Biophysical Phenomena↗
The Juvenile Arthritis Functional Status Index (JASI): a validation study.
OBJECTIVE: To evaluate aspects of reliability and validity of the Juvenile Arthritis Functional Status Index (JASI). We developed this questionnaire to assess a variety of daily living and functional mobility tasks in children with juvenile rheumatoid arthritis (JRA). JASI part I consists of 100 functional items divided into 5 activity categories (self-care, domestic, mobility, school, extracurricular). A 7 point degree of difficulty rating scale is used for responses. JASI Part II is a priority function section within which the child identifies and scores important activities for improvement. METHODS: The JASI was administered to 30 children with JRA 8 to 19 years of age at baseline, 3 weeks, and 3 months to determine test-retest reliability. Various rheumatology measures were used to evaluate the JASI construct validity. RESULTS: Reliability of JASI Part I was excellent (intraclass correlation coefficients > or = 0.95) for both retest intervals. Reliability was lower for respondents with mild disease than those with polyarticular disease. JASI Part I scores correlated strongly with rheumatology measures including joint count, grip strength, hip synovitis, timed walk and run. ACR functional class, and range of motion (r > 0.50), indicating construct validity. There was fair to good agreement between scores from the child's self-report and those from therapist observation of the child's abilities on the same activities. This provides evidence that children as young as 8 years of age can realistically report on function on their own. In JASI Part II, respondents identified a mean of 5.9 functional items in the baseline priority activity list. Test-retest reliability for JASI Part II was fair (kappa = 0.57). Further work is needed to determine the most reliable and sensitive response sequence for evaluating change in priority functions with JASI Part II. CONCLUSION: JASI Part I is a reliable and valid functional measure for school age children and adolescents with JRA. Research is under way to evaluate responsiveness to change. Comparisons will be made with shorter JRA functional measures to determine differences in sensitivity.
Activities of Daily Living↗
The effects of air cavities on X-ray dose distribution at 6 and 25 MV.
Three different air channels were constructed in solid water. These resemble upper respiratory and larynx geometry. Central-axis depth-dose distributions were measured on and beyond the distal surface of the air cavities. The measurements were made with a parallel-plate Markus ionisation chamber and TLDs for 6 and 25 MV X-ray beams of field sizes 4 cm x 4 cm and 4 cm x 7 cm. Measured dose was then compared to calculated dose for the Clarkson Scatter Integration and Equivalent Tissue-air Ratio (ETAR) algorithms. Both algorithms show errors in dose calculation at the distal surface of air cavities mainly because they fail to account for the effect of electronic disequilibrium. The magnitude of prediction error is found to depend on energy, field size and cavity geometry. For a 4 cm x 4 cm field at 6 MV the dose difference between the calculated value and the measured value, at the distal surface of square cavity is 8.2% and 13.7% for the ETAR and Clarkson algorithm respectively while that for a 4 cm x 7 cm field, the dose difference is reduced to 1.4% and 7.1% respectively. In general the ETAR algorithm shows better performance than the Clarkson algorithm because the Clarkson method calculates scatter dose assuming a homogeneous water medium while the ETAR uses a weighted sum of scatter components which is density dependent. The measured data can be used as benchmark data in the development and testing of new photon dose calculation algorithms.
Air↗
An analysis of the effectiveness of interventions intended to help people stop smoking.
In a systematic review of the efficacy of interventions intended to help people stop smoking, data have been analyzed from 188 randomized controlled trials. Following personal advice and encouragement to stop smoking given by physicians during a single routine consultation, an estimated 2% (95% confidence limits, 1%, 3%; P < .001) of all smokers stopped smoking and did not relapse up to 1 year as a direct consequence of the advice. The effect is modest but cost-effective: the cost of saving a life is about $1500. Supplementary interventions (follow-up letters or visits, demonstration of spirometry, etc) have an additional effect--variable in extent. Advice and encouragement are particularly effective for smokers at special risk--pregnant women (efficacy; 8%) and patients with ischemic heart disease. Behavior modification techniques (relaxation, rewards and punishment, avoiding "trigger" situations, etc), in group or individual sessions led by a psychologist, have an effect that is statistically significant (P = .05) but no greater than simple advice by a physician (2%); yet, these techniques are several times more expensive. The effect of hypnosis is unproved (no trials have used biochemical markers). Nicotine replacement therapy is effective in an estimated 13% of smokers who seek help in cessation; the effect is greater in those who are nicotine-dependent. Other pharmacological treatments are not of proven efficacy, and acupuncture is ineffective. Sudden cessation or gradual reduction in smoking are similar in their efficacy on average. Physicians should take time to advise all their patients who smoke to quit. Smokers who are intent on stopping should be given additional support and encouraged to use nicotine replacement therapy.
Cost-Benefit Analysis↗
Expression of 2 variant forms of fibroblast growth factor receptor 1 in human breast.
The expression of variant mRNAs encoding isoforms of fibroblast growth factor receptor (FGFR)1 with either 2 or 3 Ig-like loops in the extracellular domain was investigated in human breast tissues and cell lines using a polymerase chain reaction amplification method. Almost all tissues contained both forms of FGFR1, but cancers (n = 137) had a significantly lower proportion of the transcript that encoded the full 3-loop form compared with non-malignant biopsies (n = 34). This was confirmed using microdissected populations of normal and cancerous cells from frozen tissue sections. A high ratio of the 2- to 3-loop form was found to be predictive of reduced relapse-free survival. In both groups, however, the predominant form of FGFR1 was that encoding the 2-loop receptor. Cell lines derived from a variety of tissues, including breast, also co-expressed both variants of FGFR1, suggesting their presence within the same cell type. Again, there was a similar preponderance of the shorter isoform. Our results were confirmed at the protein level, where out of 5 cancers analysed 4 expressed more of the 2-loop form than the 3-loop form. Our findings suggest that cells may normally simultaneously express several splice variants of FGFR1, and aberrant expression or a change in their relative amounts (i.e., in malignancy) could contribute to modified responses to either autocrine or paracrine factors.
Adult↗
Regarding Stelzer and Griffin, IJROBP 27:1057-1061; 1993. Oncology Working Group.
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Acquired Immunodeficiency Syndrome↗
The role of initial AIDS-defining illness in survival following AIDS.
OBJECTIVE: To examine the role of initial AIDS-defining illness in survival following AIDS and survival trends over time. DESIGN: States and Territory Health Departments notified new diagnoses of AIDS to the National AIDS Registry. Information on vital status and date of last medical contact was sought annually. METHODS: Survival was calculated for all adult and adolescent AIDS cases (n = 3204) in Australia diagnosed until 1 November 1991 and reported to the National AIDS Registry by 31 March 1994. The Cox regression method was used to identify independent predictors for survival. RESULTS: Age < 50 years, a CD4+ cell count > or = 100 x 10(6)/l and an initial diagnosis of Kaposi's sarcoma were independently associated with longer survival (P < 0.05). Acquisition of HIV through blood transfusion and the AIDS-defining illness non-Hodgkin's lymphoma were significantly associated with shorter survival. Survival improved substantially from 1986 to 1987, but did not improve further thereafter. A further study of initial AIDS-defining illnesses in a subgroup of individuals, i.e., men aged < 50 years at diagnosis who acquired HIV infection through homosexual or bisexual contact and diagnosed after 1987, showed that Kaposi's sarcoma, Pneumocystis carinii pneumonia, oesophageal candidiasis and herpes simplex virus as initial AIDS-defining illnesses had a relatively better prognosis than other single illnesses. Furthermore, patients with multiple illnesses did not have a worse prognosis than patients with a single illness, provided all illnesses were those with a better prognosis. CONCLUSIONS: Initial AIDS-defining illness, as well as age at diagnosis, year of diagnosis, HIV exposure and CD4+ cell count at diagnosis, plays an important role in survival following AIDS in Australia.
AIDS Dementia Complex↗
Evaluation of the cost effectiveness of therapist computerized entry of occupational therapy workload measurement data.
A study was conducted to examine the cost effectiveness of two methods of managing occupational therapy workload measurement data. The computer entry of statistical data by a clerk in a central location was compared to multi-site direct input of data by therapists. Cost effectiveness, efficiency and accuracy of each method were the primary outcomes. Ease of coordination and level of computer comfort were secondary outcomes. It was clear that clerk entry of data was more cost effective, efficient and accurate than therapist entry of data. The monitoring of monthly data entry was best facilitated by clerk entry. Therapists had a positive attitude towards direct entry but were unable to approximate the speed and accuracy of the data entry clerk. Therapists' comfort with computers increased slightly during the study. Since the prime purpose of the study was to examine cost effectiveness, it was concluded that clerk entry of workload data is the best use of resources.
Canada↗
Client-centred practice: what does it mean and does it make a difference?
During the past 15 years, occupational therapists in Canada, through the Canadian Association of Occupational Therapists, have worked to develop and implement guidelines for practice of a client-centred approach to occupational therapy. One of the difficulties with the current Guidelines for the Client-Centred Practice of Occupational Therapy is the lack of a definition and discussion of the concepts and issues fundamental to client-centred practice. In this paper, key concepts of client-centred practice: individual autonomy and choice, partnership, therapist and client responsibility, enablement, contextual congruence, accessibility and respect for diversity are discussed. Two practice examples are used to illustrate these ideas and raise issues about obstacles to the practice of client-centred occupational therapy. Research evidence about the effectiveness of client-centred concepts in enhancing client satisfaction, functional outcomes and adherence to health service programmes is reviewed.
Canada↗
The health service and personal costs of screening.
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Cost-Benefit Analysis↗
Use of personal medical records for research purposes.
The established practice of doctors using medical records for research purposes is threatened by the recent proposed guidelines from the Department of Health, the BMA, and the European Commission. The European Commission has proposed that explicit consent should be obtained from each patient before his or her medical records can be used; the proposals from the Department of Health and the BMA would require all research that needs access to personal medical records to be submitted to an ethics committee. We believe that these proposals would seriously impair an entire category of research and suggest therefore that another set of guidelines, proposed by a Royal College of Physicians' working group, should be used to modify the proposals. The guidelines of the working group encourage the use of medical records for research and ensure that such use can be made in a confidential manner without causing harm.
Biomedical Research↗
Apolipoproteins and ischaemic heart disease: implications for screening.
Apolipoproteins and lipids are established risk factors of ischaemic heart disease (IHD) but their efficacy as screening tests is not known. We therefore examined the mortality from IHD and serum concentrations of lipids and apolipoproteins in a prospective study of 21,520 men aged 35-64 years. Serum apo B was the apolipoprotein most strongly associated with IHD risk; a decrease in apo B of 10% was associated with 22% lower risk of IHD. However, measurement of apo B alone detected only 17% of all IHD deaths at the cost of a 5% false-positive rate. Combining apo B with apo AI and apo (a) increased the detection rate to 19%. With systolic blood pressure, smoking, and family history of IHD the detection rate increased to 28%. We conclude that screening for IHD by measuring apo B alone or with apo AI and apo (a) is too poor to discriminate between recommending drug therapy or lifestyle change for some and not others. It is not advisable to screen for IHD by measuring any combination of cholesterol, apo B, apo AI, apo (a) and the other risk factors. The primary aim in prevention of ischaemic heart disease should be to lower the risk factors in the population.
Adult↗
How effective is nicotine replacement therapy in helping people to stop smoking?
OBJECTIVE: To assess the efficacy of nicotine replacement therapy in helping people to stop smoking. DESIGN: Analysis of the results of 28 randomised trials of nicotine 2 mg chewing gum, six trials of nicotine 4 mg chewing gum, and six trials of nicotine transdermal patch. SUBJECTS AND SETTING: Subjects were self referred (responding to advertisements or attending anti-smoking clinics) in 20 trials and invited (general practice or hospital patients) in 20. Therapists in self referred trials were generally experienced in helping people stop smoking but not in invited trials. MAIN OUTCOME MEASURE: Efficacy was defined as difference in percentages of treated and control subjects who had stopped smoking at one year. RESULTS: Efficacy was highly significant (P < 0.001) for both gum and patch. Nicotine 2 mg chewing gum had an overall efficacy of 6% (95% confidence interval 4% to 8%), greater in self referred subjects than in invited subjects (11% v 3%). Efficacy depended on the extent of dependence on nicotine as assessed by a simple questionnaire; it was 16% (7% to 25%) in "high dependence" smokers, but in "low dependence" smokers there was no significant effect. The 4 mg gum was effective in about one third of "high dependence" smokers. The efficacy of the nicotine patch (9% (6% to 13%) overall) was less strongly related to nicotine dependence, perhaps because the patch cannot deliver a bolus of nicotine to satisfy craving. CONCLUSIONS: Both gum and patch are effective aids to help nicotine dependent smokers who seek help in stopping. Among the most highly nicotine dependent smokers (those craving a cigarette on waking) the 4 mg gum is the most effective form of replacement therapy; it could enable one third to stop. In less highly dependent smokers the different preparations are comparable in their efficacy but the patch offers greater convenience and minimal need for instruction in its use. Overall, nicotine replacement therapy could enable about 15% of smokers who seek help in stopping smoking to give up the habit.
Administration, Cutaneous↗