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Biomedical subjects

N Lightfoot

Publications and source records attributed to N Lightfoot.

18 recordsLinked to original sources
PubMed2001

Radiotherapy education among family physicians and residents.

BACKGROUND: This study was performed to assess radiotherapy education among family physicians. METHODS: A questionnaire evaluating radiotherapy training and knowledge was given to participants of a palliative care conference. RESULTS: Thirty-four physicians completed the survey (71% response rate). Major deficiencies in radiotherapy education were identified and 88% of respondents stated that they did not have adequate knowledge. Only 33% had received formal training in radiotherapy and the majority (77%) thought that they would benefit considerably from continuing medical education. CONCLUSIONS: Better education about radiotherapy is required for family physicians and could lead to increased patient referral for such treatment.

Adult↗
PubMed2001

Deliberate releases of biological agents: initial lessons for Europe from events in the United States.

The experience of autumn 2001, when anthrax spores were released in the postal system, had considerable consequences in the United States and in Europe. The threat of covert deliberate releases against civilians has become a reality. In Europe, despite the growing number of criminal hoaxes, no cases of anthrax linked to deliberate releases have been reported, and the only contaminated letters were addressed to American embassies abroad. Nevertheless, the time has come for Europe to set up efficient and timely plans to respond to bioterrorism, under the coordination of the European Commission.

Anthrax↗
PubMed2000

Prostate cancer risk. Medical history, sexual, and hormonal factors.

PURPOSE: Various medical conditions, infectious agents, sexual, and hormonal factors have been investigated in relation to prostate cancer risk. Given inconsistent results these factors were examined in this study.METHODS: This population-based case-control study was conducted in northeastern Ontario from 1995 to 1999. Cases (n = 760), aged 45 to 84 at the time of diagnosis, were identified through the Ontario Cancer Registry and diagnosed between January 1995 and December 1998. Controls (n = 1,634) were age-frequency matched and were selected from the northeastern Ontario population using published telephone listings. Mail and telephone questionnaires were used for data collection. Logistic regression was used to investigate risk associated with: 1) particular medical conditions and 2) hormonal and sexual factors. Cases were subdivided into those with symptoms of prostate disease and those with few or no such symptoms.RESULTS: Symptomatic cases who reported a history of venereal disease (age-adjusted odds ratio (OR) = 2.11, 95% confidence interval (CI) 1.18-3.80) and vasectomy (age-adjusted OR = 1.49, 95% CI 1.14-1.95) were at significantly increased risk of prostate cancer. Asymptomatic cases who reported a check-up at least once a year were at increased risk (age-adjusted OR = 1.46, 95% CI 1.08-1.98). Asymptomatic and symptomatic cases who reported a history of prostate cancer in a first degree relative were at increased risk (age-adjusted OR = 2.41, 95% CI 1.64-3.54; age-adjusted OR = 3.18, 95% CI 2.28-4.45, respectively). Symptomatic cases with a history of urinary tract infection were at non-significantly increased risk (age-adjusted OR = 1.31, 95% CI 0.98-1.76). Heart disease, mumps, allergies, and height were generally not associated with prostate cancer.CONCLUSIONS: A history of venereal disease, family history of prostate cancer, and vasectomy were positively associated with prostate cancer. Further investigation of selected medical conditions, sexual, and hormonal factors in prostate cancer development is warranted.

Journal Article↗
PubMed2000

Impact of noninvasive imaging on increased incidental detection of renal cell carcinoma.

OBJECTIVE: To determine the impact of non-invasive imaging, specifically ultrasound imaging and computed tomography, on the incidental detection of renal cell carcinoma during two consecutive time periods, one prior and one subsequent to the acquisition of imaging equipment. METHODS: All located patient charts (83% of 207) of renal cell carcinoma cases (n = 172) were reviewed, and categorized by presentation method as 'incidental' or 'nonincidental' cases, based on defined criteria. Clinical information was recorded, cases were staged, and survival estimates were calculated. RESULTS: More than a third of the 172 cases were categorized as incidentally detected, most of which (82.5%) were detected during the latter time period. Either ultrasound or CT imaging was credited with detecting over 80% of the incidentally detected tumors. CONCLUSION: Ultrasound and CT imaging have contributed to the incidental detection of renal cell carcinomas during the two time periods. Stage significantly predicted survival (p<0.001) in a Cox proportional hazard model that also controlled for presentation, sex, and age.

Carcinoma, Renal Cell↗
PubMed1998

Psychological distress associated with organized breast cancer screening.

Regular breast cancer screening with the use of mammography for asymptomatic women is the most effective method for the early detection of breast cancer. Although the health and economic implications of breast cancer screening have received a great deal of attention, the psychological consequences of attending a breast screening program that includes mammography have been largely ignored. This article briefly reviews 10 studies that have examined the psychological distress associated with organized breast cancer screening. Anxiety appears to be the most prevalent consequence of mammography and seems to affect certain subgroups, with the most significant effects being among those women requiring further investigation because of abnormal results. The results of these studies, the research methods used and future directions in this area are discussed.

Aged↗
PubMed1998

A large outbreak of cryptosporidiosis associated with a public water supply from a deep chalk borehole. Outbreak Investigation Team.

Three hundred and forty-five confirmed cases were reported in a large waterborne outbreak of cryptosporidiosis in North Thames in the spring of 1997. The descriptive epidemiology, attack rates, a case control study, and the detection of oocysts in the water suggested strongly that the outbreak was associated with drinking unboiled tap water that originated from one deep chalk borehole. The 746,000 people living in the water distribution area were advised to boil their drinking water. Investigations did not reveal how oocysts entered the borehole. This is the first published report of a cryptosporidium outbreak caused by filtered borehole water and we believe it to be the largest outbreak due to groundwater to have been reported. Borehole supplies are regarded as relatively pure sources of water and this outbreak has implications for the future monitoring and treatment of drinking water extracted from boreholes.

Adolescent↗
PubMed1997

Hypnosis for children and adolescents with cancer: an annotated bibliography, 1985-1995.

This annotated bibliography reviews the professional literature published in English, from 1985 to 1995 inclusive, on the subject of the use of hypnosis with pediatric cancer patients. Books, chapters, and journal articles are included; dissertation, theses, and unpublished material are not. This bibliography contains 37 items organized into three categories: (1) General Discussions; (2) Case Reports or Case Studies: and (3) Experimental and Nonexperimental Group Designs. The brief annotations provided are not intended to be reviews or to be evaluative, but, rather, to inform the reader about the content and focus of the publication. This is an update of a previously published annotated bibliography, also presented in this Journal, which explored the relationship between hypnosis and pediatric cancer in journal articles published from 1960 to 1985.

Adolescent↗
PubMed1995

Radiotherapy portal verification: an observer study.

In many radiotherapy facilities radiotherapy portal verification is currently a subjective process based on the visual comparison of a treatment or portal image with a prescription or simulation image. The reliability of this process is unknown. We describe here a study in which 16 observers (oncologists, physicists and therapists) independently evaluated the geometric accuracy of 530 treatment fields on 45 patients. The treatment images were acquired by the BEAMVIEW on-line portal imaging system (Siemens Medical Laboratories, Concord, CA, USA). Illustrative examples of the large variation in observers' assessments of the same field are given. The kappa statistic is used to evaluate the degree of agreement between observers and between on-line (at the treatment unit) and off-line (in a quiet viewing room) assessments. The best interobserver agreement was between the four oncologists contributing to the study although this level of agreement was rated only as "fair". Comparison of on-line and off-line decisions made by therapists exhibited "poor" agreement. This study has provided statistical confirmation of the suspicions of many workers in the field of radiotherapy portal verification, viz that the subjective evaluation of field accuracy is unreliable. However, the degree of unreliability is surprisingly large. The inconsistencies between observers documented in this study need to be clearly acknowledged in the development of protocols for the clinical use of on-line portal imaging systems. Acceptable reliability in radiotherapy portal verification will only be achieved when subjective decision making is eliminated.

Humans↗
PubMed1992

Automatization and training in visual search.

In several search tasks, the amount of practice on particular combinations of targets and distractors was equated in varied-mapping (VM) and consistent-mapping (CM) conditions. The results indicate the importance of distinguishing between memory and visual search tasks, and implicate a number of factors that play important roles in visual search and its learning. Visual search was studied in Experiment 1. VM and CM performance were almost equal, and slope reductions occurred during practice for both, suggesting the learning of efficient attentive search based on features, and no important role for automatic attention attraction. However, positive transfer effects occurred when previous CM targets were re-paired with previous CM distractors, even though these targets and distractors had not been trained together. Also, the introduction of a demanding simultaneous task produced advantages of CM over VM. These latter two results demonstrated the operation of automatic attention attraction. Visual search was further studied in Experiment 2, using novel characters for which feature overlap and similarity were controlled. The design and many of the findings paralleled Experiment 1. In addition, enormous search improvement was seen over 35 sessions of training, suggesting the operation of perceptual unitization for the novel characters. Experiment 3 showed a large, persistent advantage for CM over VM performance in memory search, even when practice on particular combinations of targets and distractors was equated in the two training conditions. A multifactor theory of automatization and attention is put forth to account for these findings and others in the literature.

Adult↗
PubMed1991

Analysis of survival in patients with pulmonic valve atresia and ventricular septal defect.

This study reviews the clinical course of 104 consecutive patients with pulmonic valve atresia and ventricular septal (VSD) defect who were diagnosed in the first year of life and followed for a mean period of 4.95 years (range 2 days to 13.75 years). Specific attention was paid to the nature of the pulmonary blood supply and to its influence on patient outcome. Confluent pulmonary arteries supplied by a single ductus arteriosus were present in 72 patients (69%, group I), whereas 32 patients (31%, group II) had a pulmonary blood supply that was partially or exclusively dependent on systemic collateral arteries. An estimate of the probability of survival for 10 years was 69% in the entire cohort, with no different between patients in group I and group II. Definitive surgical repair was performed in 33 of 72 group I patients (46%), compared with 5 of 32 group II patients (16%). Arborization and distribution abnormalities of the pulmonary arteries as well as intrapulmonary stenoses that were exclusively present in patients with systemic collateral arteries (p less than 0.00001) accounted for the significantly lower probability of undergoing corrective surgery in group II patients.

Analysis of Variance↗
PubMed1985

Epidemic hypochlorhydria.

During a study of gastric secretion four out of six previously healthy subjects developed hypochlorhydria after a transient illness with nausea, vomiting, and abdominal pain. Mean basal and peak acid outputs were 0 and 2.3 mmol (84 mg)/h one month after the onset of illness and 1.5 and 27.0 mmol/h (55 and 984 mg/h) at eight months' follow up. Two of the subjects were followed up at 18 months, when mean basal and peak acid outputs were 3.9 and 33.5 mmol/h (142 and 1221 mg/h). No endoscopic abnormality was seen at one and eight months, but biopsies showed active superficial gastritis, which resolved in one subject and became chronic in two. Schilling tests performed in three subjects at eight months showed diminished retention of vitamin B12. During hypochlorhydria a 24 hour intragastric analysis was performed for total and nitrate reducing bacteria, pH, and concentrations of nitrite and total and stable N-nitroso compounds. Of the 48 samples of gastric juice examined, 47 had bacterial growth of more than 10(6) organisms/ml and 46 had growth of nitrate reducing bacteria of more than 10(5) organisms/ml. Mean intragastric nitrite concentrations were 10 times higher than in a group of eight healthy controls. Both mean total and mean stable N-nitroso compound concentrations, however, were not appreciably different from those in controls. Although community transmission was a possibility, serological screening and electron microscopy of gastric biopsy specimens failed to show an infective cause. Transmission of an unidentified enteric pathogen via a contaminated pH electrode was therefore suspected. Thus gastric juice should not be returned to the stomach after contact with a contaminated glass electrode as this is a possible cause of atrophic gastritis.

Achlorhydria↗
PubMed1981

A pilot study of skin disinfection in the hyperbaric environment.

An opportunity was taken to carry out a pilot on human skin disinfection during a recent long-term saturation dive at extremely high pressure. Despite a number of difficulties, results were sufficiently encouraging to suggest that, given ideal conditions, sterilization of the skin in preparation for surgical or anesthetic procedures, or both, in a hyperbaric environment is possible.

Atmospheric Pressure↗
PubMed1976

A retrospective serological suvey of Royal Marines previously exposed to Pseudomonas pseudomallei in South East Asia.

Following the suggestion that it was possible that cases of melioidosis amongst those who had been exposed abroad in the past, might be escaping notice, 487 Royal Marines were examined by indirect haemagglutination studies. Four hundred and eleven of these subjects had served for variable times in areas where melioidosis has been known to occur in Indonesia and Malaya, between 1960 and 1974, occupied in activities in the jungle and paddy fields during which exposure to the disease was to be expected. No evidence of residual subclinical melioidosis was found and it seems unlikely that recrudescent disease will prove to be a problem in the future for English servicemen who have been in South East Asia.

Antibodies, Bacterial↗