Biomedical subjects

M J Gardner

Publications and source records attributed to M J Gardner.

At least 127 records · Page 7Linked to original sources

PubMed1990

An exploratory study of statistical assessment of papers published in the British Medical Journal.

Statistical assessment of papers submitted to the British Medical Journal has increased to some 300 papers annually. The assessment produces a recommendation to the editor on each paper from a statistical viewpoint together with a completed checklist that indicates the quality of certain important features. This exploratory study was aimed at monitoring the process. It reports a comparison of checklist answers on 45 papers as originally submitted with those on the papers as subsequently published. Of the 45 papers, only 5 (11%) were considered statistically acceptable at submission, but this increased to 38 (84%) after publication. Revisions had not been made adequately in 4 of the 7 unsatisfactory published papers, and the 3 others were thought to be of dubious validity. A major omission from at least 28 papers was information on sample size calculations. It is concluded that statistical assessment is beneficial but that further efforts by authors and assessors could make it even more effective.

Peer Review↗

PubMed1990

Results of case-control study of leukaemia and lymphoma among young people near Sellafield nuclear plant in West Cumbria.

OBJECTIVE: To examine whether the observed excess of childhood leukaemia and lymphoma near the Sellafield nuclear plant is associated with established risk factors or with factors related to the plant. DESIGN: A case-control study. SETTING: West Cumbria health district. SUBJECTS: 52 Cases of leukaemia, 22 of non-Hodgkin's lymphoma, and 23 of Hodgkin's disease occurring in people born in the area and diagnosed there in 1950-85 under the age of 25 and 1001 controls matched for sex and date of birth taken from the same birth registers as the cases. MAIN OUTCOME MEASURES: Antenatal abdominal x ray examinations, viral infections, habit factors, proximity to and employment characteristics of parents at Sellafield. RESULTS: Expected associations with prenatal exposure to x rays were found, but little information was available on viral illnesses. Relative risks for leukaemia and non-Hodgkin's lymphoma were higher in children born near Sellafield and in children of fathers employed at the plant, particularly those with high radiation dose recordings before their child's conception. For example, the relative risks compared with area controls were 0.17 (95% confidence interval 0.05 to 0.53) for being born further than 5 km from Sellafield 2.44 (1.04 to 5.71) for children of fathers employed at Sellafield at their conception, and 6.42 (1.57 to 26.3) for children of fathers receiving a total preconceptual ionising radiation dose of 100 mSv or more. Other factors, including exposure to x rays, maternal age, employment elsewhere, eating seafood, and playing on the beach did not explain these relationships. Focusing on Seascale, where the excess incidence has predominantly been reported, showed for the four out of five cases of leukaemia and one case of non-Hodgkin's lymphoma whose fathers were employed at Sellafield and for whom dose information was obtained that the fathers of each case had higher radiation doses before their child's conception than all their matched control fathers; the father of the other Seascale case (non-Hodgkin's lymphoma) was not employed at the plant. These results seem to explain statistically the geographical association. For Hodgkin's disease neither geographical nor employment associations with Sellafield were found. CONCLUSIONS: The raised incidence of leukaemia, particularly, and non-Hodgkin's lymphoma among children near Sellafield was associated with paternal employment and recorded external dose of whole body penetrating radiation during work at the plant before conception. The association can explain statistically the observed geographical excess. This result suggests an effect of ionising radiation on fathers that may be leukaemogenic in their offspring, though other, less likely, explanations are possible. There are important potential implications for radiobiology and for protection of radiation workers and their children.

Case-Control Studies↗

PubMed1990

Methods and basic data of case-control study of leukaemia and lymphoma among young people near Sellafield nuclear plant in West Cumbria.

Case-Control Studies↗

PubMed1990

How bicycle-related injuries change bicycling practices in children.

Bicycle crashes are a major cause of injuries in childhood. The goal of this study was to determine the effects of bicycle-related injuries on the subsequent bicycle-riding behavior and safety practices of the child and other family members. Successful telephone contact was made with the parents of 82 of 230 children (age at time of injury, 4 to 15 years; median, 9 years; 57 boys and 25 girls) admitted to the hospital with bicycle-related injuries from 1983 to 1986. Parents were interviewed by telephone 4 months to 6 years after injury (median, 1 year 9 months). Head injuries predominated (64.6%). Almost all children continued to ride a bicycle after hospitalization (80 [97.6%] ). Few wore a bicycle helmet either before (6 [7.3%] ) or at the time of injury (3 [3.7%] ). More began wearing helmets after hospital discharge (20 [24.4%] ), but three fourths of the children still rode their bicycles without protective head wear. Helmet wearing also increased among bicycle-riding siblings after the index hospitalization (3 [7.0%] of 43 vs 7 [16.3%] ) but the difference was not significant. Parents commonly imposed restrictions on bicycle riding before hospitalization (78.0%) and after hospital discharge (82.9%). Twenty-six families (31.7%) reported more stringent rules after injury. Only 17 children (20.7%) participated in formal bicycle safety programs before the injury; only 5 (6.1%) more went through such a program after hospital discharge. Alone, an injury seems to have limited effect on the adoption of safe bicycling practices among children. The hospitalization of injured children provides opportunities for safety education to foster safe bicycling and to prevent injuries of all causes.

Accident Prevention↗

PubMed1990

Emergency endotracheal intubation in pediatric trauma.

The purpose of this study was to determine the effectiveness and associated problems of emergency intubation in 605 injured infants and children admitted to the Children's Hospital of Pittsburgh in 1987. We identified 63 patients (10.4%) undergoing endotracheal intubation at the scene of injury, at a referring hospital or in our emergency department. Injuries were to the head (90.5%), abdomen (12.7%), face (11.1%), chest (6.3%), neck (3.2%); or were orthopedic (19%) or multiple (39.7%). Indications for intubation included coma (74.6%), shock (28.6%), apnea (22.2%), and airway obstruction (3.2%). Of 16 complications (25.4%), 13 were immediately life threatening: right mainstem intubation (5), massive barotrauma (2), failure of adequate preoxygenation (2), esophageal intubation (1), attempt at nasotracheal intubation in an open facial fracture (1), and extubation during transport (1). Three were late complications: vocal cord paresis (2) and subglottic stenosis (1). Airway complications led to PO2 less than 90 mm Hg in 7 of 12 on first ABG, compared to 9 of 44 in uncomplicated cases (p less than 0.05). Intubation attempts at the scene of injury were more often multiple, unsuccessful, and associated with airway complications. All four complication-associated fatalities were life-threatening scene complications. Nearly one half (44.4%, 28 of 63) had one of the following problems in respiratory management: major airway complication, PaO2 less than 90, or PaCO2 greater than 45 on either the first or second ABG after arrival at our emergency department. Head injury with coma is the most common setting for emergency intubation. Airway complications are common, and are more frequent in treatment attempt at the scene. Despite endotracheal intubation, injured children in our series remain at high risk for hypoxemia, elevated arterial PCO2, and major airway complications, all of which contribute to secondary brain injury.

Adolescent↗

PubMed1990

Disability from bicycle-related injuries in children.

Bicycle crashes are a major cause of injuries in childhood. The goal of this study was to determine the long-term disabilities caused by bicycle-related injuries, and to clarify the long-term treatment priorities of injured children. Hospital records of 372 children (ages 2-15 yr, median 9 yr; 232 boys and 140 girls) admitted with bicycle-related injuries from 1979 through 1986 provided clinical information, social service visits, in-hospital and outpatient rehabilitative interventions, and physical status at discharge. More complete evaluations were made by contacting parents by telephone (82 children), and by personal interview and physical examinations (27). Head injuries predominated (69.1%). Twelve (3.2%) died, all from major head injuries. Four suffered permanent severe impairment from cervical spinal injuries and head injuries and remain institutionalized (1.4%). One third had a persistent disability noted at the time of discharge in the medical record (33.6%), reported by telephone interview (31.7%), or confirmed by physical examination (37.0%). Still, only 11.0% received physical therapy consultations during hospitalization, and 22.8% received social service assistance. Only 39.0% were seen by a surgeon or pediatrician after discharge, and few (7.3%) received outpatient physical therapy. Cognitive or behavior changes were noted in 31.7%, many noting changes in school performance (worse in 20.7%), behavior (13.4%), and sleep, particularly nightmares (34.1%). Recurrent injuries occurred in 52 children (14.4%), of whom ten (2.8%) required further hospital admission. Bicycle-related injuries cause significant short- and long-term disabilities among children.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

Effects of increasing heart rate induced by efferent sympathetic neuronal stimulation, isoproterenol or cardiac pacing on myocardial function and oxygen utilization.

The effects of increasing heart rate by six different methods on cardiac function were investigated in 17 open-chest anesthetized dogs. Heart rate was increased approximately 30% by (1) right interganglionic nerve stimulation, (2) atrial pacing, (3) ventricular pacing, (4) atrioventricular sequential pacing, (5) right stellate ganglion stimulation, and (6) isoproterenol administration. During heart rate increases induced by atrial pacing left ventricular intramyocardial pressure, coronary blood flow, oxygen delivery per unit of myocardial oxygen consumption, and myocardial efficiency were unchanged. Ventricular pacing reduced left ventricular cavity and septal intramyocardial pressure, while circumflex coronary flow increased, resulting in reduced oxygen delivery relative to myocardial oxygen consumption. Similarly, atrioventricular sequential pacing increased circumflex coronary artery flow and myocardial oxygen consumption, and decreased septal intramyocardial pressure and oxygen delivery per unit of myocardial oxygen consumption. Right stellate ganglion stimulation and isoproterenol increased left anterior descending and circumflex coronary artery blood flow, intramyocardial pressure, and myocardial oxygen consumption. Estimated myocardial efficiency (left ventricle) was decreased by ventricular pacing and isoproterenol, and was unchanged by atrial pacing and right interganglionic nerve stimulation. Increases in heart rate induced by right interganglionic nerve stimulation did not alter myocardial oxygen consumption, or the index of cardiac efficiency. It is concluded that augmentation of heart rate by either ventricular or atrioventricular pacing impairs myocardial function so that there is a decrease of left ventricular efficiency and isoproterenol augments chronotropism and myocardial force relative to cardiac external work so there is a reduction in cardiac efficiency. In contrast, atrial pacing or right interganglionic nerve stimulation augments chronotropism such that myocardial oxygen consumption and efficiency are unchanged.

Animals↗

PubMed1990

Confidence--and clinical importance--in research findings.

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Confidence Intervals↗

PubMed1990

Long-term reductions in GH, insulin-like growth factor-I and body weight gain in rats treated neonatally with antibodies to rat GH.

Treatment of neonatal rats on days 2-5 with antibodies against rat GH (rGH) markedly reduced body weight gain and serum concentrations of insulin-like growth factor-I for 6-8 weeks in both females and males, after which weight gain normalized without evidence of catch-up growth. There were no significant effects on serum prolactin, tri-iodothyronine or corticosterone. Testis and ovarian weights were reduced, although only in proportion to body size. In females, but not males, the treated rats, though lighter, had increased fat deposition in the parametrial depot. Pituitary weight was considerably reduced over 100 days later, as was the pituitary content of GH, but not prolactin. The response to GH-releasing factor of both male and female rats was also greatly reduced at this time. Taken together with the fact that these rGH antibodies can bind directly to somatotrophs, we propose that the long-term effects of the antibodies are induced by specific somatotroph destruction.

Animals↗

PubMed1990

Production of anti-idiotypic antisera to rat GH antibodies capable of binding to GH receptors and increasing body weight gain in hypophysectomized rats.

Anti-idiotypic antibodies to rat GH antibodies were produced in both sheep and mice and shown to be capable of mimicking GH by inhibiting 125I-labelled ovine GH (oGH) binding to sheep liver membranes. The sheep anti-idiotypes were characterized further and shown to (1) inhibit 125I-labelled oGH binding to oGH antibodies, (2) inhibit 125I-labelled oGH binding to rat adipocytes and (3) be incapable of inhibiting the binding of either 125I-labelled ovine prolactin or 125I-labelled bovine insulin to sheep liver membranes. This indicated that the antibodies were not limited to certain species or tissues, but were hormone specific. Finally, these anti-idiotypic antibodies were also capable of stimulating an increase in body weight gain in hypophysectomized rats, suggesting that they may be functional as well as structural mimics of GH, although the increased body weight gain was not accompanied by any increase in circulating concentrations of insulin-like growth factor-I.

Animals↗

PubMed1990

The trauma registry: an administrative and clinical tool.

A commitment to the maintenance of a comprehensive trauma registry can provide numerous benefits, both administrative and clinical. Uses of the information collected can vary in nature and scope based on the needs of the facility and the requirements of external regulatory bodies. Ultimately, the choice of data applications rests with the facility collecting the information. As the facility grows and evolves, so can--and must--its registry.

Adolescent↗

PubMed1990

A mortality follow-up study of pottery workers: preliminary findings on lung cancer.

The possible association between exposure to low levels of silica and lung cancer was investigated by following up pottery workers included in a survey conducted in 1970-71 of respiratory disease among such workers. The initial results show that, among men under the age of 60 at the time of the original survey, mortality has been similar to that expected, but that there was an excess of lung cancer of over 30% even after allowance had been made for cigarette smoking and place of residence. There were no particular excesses of lung cancer by product group or job group. However, there was some indication that lung cancer risk increased with estimated cumulative exposure to respirable quartz. These findings do suggest an association between lung cancer and the low levels of silica found in potteries, and the follow-up will therefore be continued and a more detailed analysis of the data carried out.

Adult↗

PubMed1989

Dietary aluminium and Alzheimer's disease.

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Aluminum↗

PubMed1989

Persistent changes in the body surface electrocardiogram following successful coronary angioplasty.

One hundred twenty-lead body surface potential maps (BSPMs) were recorded immediately before and 24 hours after coronary angioplasty (PTCA) in 24 patients with symptomatic coronary artery disease (single-vessel in 21 and two-vessel in 3). All PTCAs were uncomplicated and successful. The modified Gensini score decreased in every patient and the mean score fell from 43 +/- 36 to 21 +/- 28 (p less than 0.001). Resting spatial patterns of QRS, ST-segment, and T wave integral distributions over the torso surface were unchanged from before to after PTCA. Quantitative temporal subtraction maps, however, revealed a large precordial area of decreased T wave integral values after PTCA. The sum (sigma) positive T wave integrals fell from 20,501 +/- 10,544 microV.s before PTCA to 17,647 +/- 10,310 microV.s after PTCA (p less than 0.02). In contrast, the sigma positive QRS (10,115 +/- 4,848 microV.s before PTCA vs. 9,656 +/- 4,556 microV.s after PTCA) and the sigma negative ST integrals (-2,489 +/- 1,467 microV.s before PTCA vs. -2,359 +/- 1,505 microV.s after PTCA) were unchanged (NS). Thus, successful PTCA does not produce any persistent change in depolarization or early repolarization electrocardiographic variables but is associated with a decrease in late repolarization potentials that persists for at least 24 hours after the procedure. The pathophysiology of this persistent change is speculative, but myocardial ischemia during the PTCA procedure is a likely possibility. The clinical significance, including predictive value for subsequent stenosis, and the natural history of T wave effect remain incompletely defined. These data suggest that measures to decrease myocardial ischemia during PTCA are warranted.

Adult↗

PubMed1989

Quality assessment in the pediatric trauma care system.

The goal of the pediatric trauma care system is to prevent death, disability, and suffering of injured children. Quality assessment (QA), the evaluation of clinical performance and quality, is essential not only for formal accreditation processes, but also for day-to-day trauma center operation. QA involves three basic types of performance measures: input, process, and outcome. Input measures are inventories of the resources of a given institution, such as the availability of a surgeon on a 24-hour-a-day in-house basis. They give baseline descriptions of facilities and do not monitor performance directly. Process measures attempt to verify that the system is using its resources appropriately in response to demands, which at Children's Hospital of Pittsburgh (CHP), involves tracking all admitted patients from injury to discharge with the assistance of a system of audit screens to help identify problem cases. The methodology of the Major Trauma Outcome Study (MTOS) provides basic outcome data by identifying unexpected survivors and deaths. However, the few cases identified (four of 316 patients submitted to MTOS; 1.3%) limit conclusions regarding trauma center performance. Performance measures, when applied to admitted trauma patients, allow timely recognition of individual complications and problem trends. QA provides necessary data for important clinical decisions and resource allocations that affect trauma center operation.

Child↗

PubMed1989

Age, period, and cohort models. Non-overlapping cohorts don't resolve the identification problem.

Age, period, and cohort models have generally been applied to rates from tabulated national statistics, and it is known that such models suffer from an identification problem. When individual records, including date of birth, are available, however, a unique solution has been proposed which uses non-overlapping cohorts. We have shown that the identification problem exists in continuous time, so that even perfect information on the three variables will fail to resolve it. It is important to recognize clearly the assumptions that are implicit in the non-overlapping cohort formulation of the age-period-cohort model. The value of the solution proposed depends critically on their appropriateness or otherwise. It should always be remembered that the assumptions determine much of the final solution, including the apportionment of trend to the different components, age, period, or cohort.

Age Factors↗

PubMed1989

Calculating expected numbers of deaths in cohort studies.

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Cohort Studies↗

PubMed1989

Workers exposed to ethylene oxide: a follow up study.

A cohort study has been carried out of 2876 men and women with potential exposure to ethylene oxide. Subjects were identified from employment records at four companies that have produced or used ethylene oxide since the 1950s and at eight hospitals which have had ethylene oxide sterilising units since the 1960s. The cohort represents a substantial proportion of the British workforce with a history of occupational exposure to ethylene oxide. Industrial hygiene data were not available before 1977, but since then time weighted average exposures have been less than 5 ppm in almost all jobs and less than 1 ppm in many. Past exposures were probably somewhat higher. In contrast to some previous studies, no clear excess of leukaemia (three deaths observed, 2.09 expected) and no increase in stomach cancer (five deaths observed, 5.95 expected) were found. This discrepancy with earlier reports may be due in part to differences in levels of exposure. Total cancer mortality was similar to that expected from national and local death rates. Some specific cancers showed small excesses but their relevance to ethylene oxide exposure is doubtful. Again, contrary to some earlier reports, no excess of cardiovascular disease was found. This study does not exclude the possibility that ethylene oxide is a human carcinogen but suggests that any risk of cancer from currently permitted occupational exposures is small.

Cardiovascular Diseases↗