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Biomedical subjects

C Robertson

Publications and source records attributed to C Robertson.

At least 127 records · Page 7Linked to original sources
PubMed1998

Effect of gap length and position on results of treatment of cancer of the larynx in Scotland by radiotherapy: a linear quadratic analysis.

PURPOSE: This paper reports on the analysis of the effect of the length and position of unplanned gaps in radiotherapy treatment schedules. MATERIALS AND METHODS: Data from an audit of the treatment of carcinoma of the larynx are used. They represent all newly diagnosed cases of glottic node-negative carcinoma of the larynx between 1986 and 1990, inclusive, in Scotland that were referred to one of the five Scottish Oncology Centres for primary radical radiotherapy treatment. The end-points are local control of cancer of the larynx in 5 years and the length of the disease-free period. The local control rates at > or =5 years, Pc were analyzed by log linear models and Cox proportional hazard models were used to model the disease-free period. RESULTS: Unplanned gaps in treatment are associated with poorer local control rates and an increased hazard of a local recurrence through their effect on extending the treatment time. A gap of 1 day is potentially damaging but the greatest effect is at treatment extensions of 3 or more days, where the hazard of a failure of local control is increased by a factor of 1.75 (95% confidence interval 1.20-2.55) compared to no gap. The time factor for the actual time was imprecisely estimated at 2.7 Gy/day with a standard error of 13.2 Gy/day. Among those cases who had exactly one gap resulting in a treatment extension of 1 day, there is no evidence that gap position influences local control (P = 0.17). The treatment extension as a result of the gap is more important than the position of the gap in the schedule. CONCLUSIONS: Gaps in the treatment schedule have a detrimental effect on the disease-free period. A gap has a slightly greater effect than an increase in the prescribed treatment time. Any gap in treatment is potentially damaging. The position of the gap in the schedule was shown to be not important.

Appointments and Schedules↗
PubMed1998

Tamoxifen reduces plasma homocysteine levels in healthy women.

Treatment with tamoxifen is associated with reduced incidence of myocardial infarction. As plasma homocysteine is an independent risk factor for cardiovascular disease, we studied the effects of tamoxifen on plasma homocysteine in 66 healthy women participating in the Italian prevention trial of breast cancer who were randomized in a double-blind manner to tamoxifen 20 mg day(-1) or placebo for 5 years. They were aged between 35 and 70 years, had undergone previous hysterectomy for non-malignant conditions and had no contraindications to the use of tamoxifen. Plasma levels of total homocysteine (tHcy) were measured at randomization and after 2 and 6 months. The mean +/- s.d. plasma levels of tHcy were 7.59 +/- 1.71 micromol l(-1), 7.25 +/- 1.61 and 7.09 +/- 1.33 in the tamoxifen group and 8.07 +/- 2.06, 7.93 +/- 1.77 and 8.12 +/- 2.04 in the placebo group at 0, 2 and 6 months (P = 0.008 for the between-group difference over time). The higher the baseline tHcy level, the greater was the lowering effect of tamoxifen. No statistically significant effect of age, body mass index or smoking habit on baseline tHcy levels and its variation over time was found. In conclusion, tamoxifen (20 mg day(-1) for 6 months) decreased plasma tHcy levels in healthy women. This effect may contribute to its protective effect on myocardial infarction.

Adult↗
PubMed1998

Effect of tamoxifen and transdermal hormone replacement therapy on cardiovascular risk factors in a prevention trial. Italian Chemoprevention Group.

The combination of tamoxifen and transdermal hormone replacement therapy (HRT) may potentially reduce risks and side-effects of either agent, but an adverse interaction could attenuate their beneficial effects. We assessed the effects of their combination on cardiovascular risk factors within a prevention trial of tamoxifen. Baseline and 12-month measurements of total, low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol, platelets and white blood cells were obtained in the following four groups: tamoxifen (n = 1117), placebo (n = 1112), tamoxifen and HRT (n = 68), placebo and HRT (n = 87). The analysis was further extended to women who were on HRT at randomization but discontinued it during the 12-month intervention period (n = 33 on tamoxifen and n = 35 on placebo) and to women who were not on HRT but started it during intervention (n = 36 in both arms of the study). Compared with small changes in the placebo group, tamoxifen was associated with changes in total, LDL- and HDL-cholesterol of approximately -9%, -19% and +0.2% in continuous HRT users compared with -9%, -14% and -0.8% in never HRT users. Similarly, there was no interaction on platelet count. In contrast, the decrease in total and LDL-cholesterol levels induced by tamoxifen was blunted by two-thirds in women who started HRT while on tamoxifen (P = 0.051 for the interaction term). We conclude that the beneficial effects of tamoxifen on cardiovascular risk factors are unchanged in current HRT users, whereas they may be attenuated in women who start transdermal HRT while on tamoxifen. Whereas a trial of tamoxifen in women already on transdermal HRT is warranted, prescription of HRT during tamoxifen may attenuate its activity.

Breast Neoplasms↗
PubMed1998

A study of proactive ethics consultation for critically and terminally ill patients with extended lengths of stay.

OBJECTIVE: To assess the effect of proactive ethics consultation on documented patient care communications and on decisions regarding high-risk intensive care unit (ICU) patients. DESIGN: Prospective, controlled study. PATIENTS: Ninety-nine ICU patients treated with >96 hrs of continuous mechanical ventilation. INTERVENTIONS: Three groups were compared: a) a baseline group enrolled in the study prior to the establishment of the hospital's ethics consultation service; b) a control group where ethics consultation was at the option of the care team; and c) a treatment group where the ethics service intervened proactively after patients received >96 hrs of continuous mechanical ventilation. Patient care planning, for subjects in the proactive group, was reviewed with physicians and with the care team using a standardized set of prompting questions designed to focus discussion of key decision-making and communication issues for critically and terminally ill patients. Issues and concerns were identified and action strategies were suggested to those in charge of the patient's care. Formal ethics consultation, using a patient care conference model, was made available upon request. MEASUREMENTS AND MAIN RESULTS: Post discharge chart reviews of the three groups indicated no statistically significant differences on important demographic variables including age, gender, and acuity. Comparisons of survivors and nonsurvivors for the three groups indicated, at statistically significant levels, more frequent and documented communications, more frequent decisions to forego life-sustaining treatment, and reduced length of stay in the ICU for the proactive consultation group. CONCLUSION: Proactive ethics consultation for high-risk patient populations offers a promising approach to improving decision-making and communication and reducing length of ICU stay for dying patients.

APACHE↗
PubMed1998

Elemental content of airway surface liquid from infants with cystic fibrosis.

We tested the hypothesis that airway surface liquid (ASL) electrolyte composition is altered in infants with cystic fibrosis (CF) and that the presence of airway inflammation affects ASL composition. We measured the tracheal ASL sodium and chloride concentration and examined bronchoalveolar lavage (BAL) fluid cytology, interleukin-8 (IL-8) concentrations, and quantitative bacterial culture in 19 infants and young children with CF. Seven infants undergoing bronchoscopy for the evaluation of stridor served as non-CF controls. In addition, we measured nasal ASL sodium and chloride concentrations from 10 young adults with CF and from 10 control subjects. On the basis of the BAL findings, the infants with CF were divided into three groups: one with little evidence of pulmonary inflammation (CF-NI, n = 5); one with obvious pulmonary inflammation (CF-I, n = 7); and an intermediate group (CF-MI, n = 7). We found the ASL sodium was not different among any of the four groups (means mM +/- SE, 85 +/- 10 controls; 78 +/- 16 CF-NI; 83 +/- 9 CF-MI, 84 +/- 9 CF-I). In contrast the ASL chloride was lower in the CF-NI group when compared with control subjects (108 +/- 5 control subjects; 77 +/- 7 CF-NI, p < 0.01). In the CF-I and CF-MI groups, the ASL chloride concentrations were of intermediate values (CF-I 95 +/- 10 mM; CF-MI 96 +/- 9 mM) and not significantly different from controls. Results from the nasal ASL analysis showed no significant differences in sodium and chloride concentrations in the CF group compared with control subjects. These results suggest that the primary abnormality of ASL composition is a reduction in chloride concentration. ASL composition appears to be affected by the presence of airway inflammation.

Adolescent↗
PubMed1998

Before viability: a geographically based outcome study of infants weighing 500 grams or less at birth.

OBJECTIVE: The primary objective of this study was to determine the likelihood of long-term survival and avoidance of disabilities in a geographically based population of infants born at 20 weeks gestation or more and weighing 500 g or less at birth. STUDY DESIGN: This was a 12-year historical cohort follow-up study of all infants born in this gestational age and birth weight category in the Province of Alberta, Canada, between 1983 and 1994. Data were collected from certificates of live births or stillbirths, death certificates, hospital records, and longitudinal multidisciplinary follow-up examinations. RESULTS: One thousand one hundred ninety-three infants were of 20 weeks gestation or more, weighed 500 g or less, and were born between 1983 and 1994. Eight hundred eleven (68.0%) were stillborn and 382 (32.0%) were born alive. Among the latter, neonatal intensive care was provided in 113 (29.6%) and withheld in 269 (70.4%). The infants receiving intensive care were of heavier birth weight, later gestational age, higher antenatal risk scores, were more likely to be born in a level III center, to have received antenatal steroids, and to have been delivered by cesarean section. Of the infants receiving intensive care, 95 (84. 1%) died and 18 (15.9%) were discharged alive, but 5 of these died after discharge because of respiratory complications. The infants discharged alive had later gestational age, were more likely to be small for gestational age, singletons, treated with antenatal steroids, and to have been delivered by cesarean section. Maternal indications were described in the majority of cesarean sections done for live-born infants. The 13 infants who were long-term survivors were followed at ages 12 and 36 months adjusted age. Four had no serious disabilities, 4 had one disability (cerebral palsy or mental retardation), and 5 had multiple disabilities (cerebral palsy plus mental retardation with blindness in 2 cases and deafness in 1 case). CONCLUSION: The majority of infants born at gestational age 20 weeks or more weighing <500 g were stillborn. Among live births, neonatal intensive care was withheld in 70% and initiated in 30%. Of the latter, 11% survived to 36 months of age, and of these, 4 infants (31%), most of whom are small for gestational age, female infants, avoided major disabilities but 9 (69%) had one or more major disabilities. Survivors are prone to rehospitalizations early in life, slow growth, feeding problems, and minor visual difficulties; rates of learning-related and behavioral problems at school age are not yet known. Implications. Parents and caregivers faced with the impending delivery of an infant in this gestational age/birth weight category should understand that survival without multiple major disabilities is possible but rare. They should be made aware of local population-based results and not just isolated reports.

Cerebral Palsy↗
PubMed1998

Risk factors for high-grade cervical intraepithelial neoplasia in patients with mild cytological dyskaryosis: human papillomavirus testing versus multivariate tree analysis of demographic data.

The objective of this study was to compare the use of molecular hybridization by hybrid capture methodology for human papillomavirus (HPV) with the use of demographic and lifestyle variables as intermediate triage in patients with cytological mild dyskaryosis. The study was designed as a prospective study using regression tree analysis of demographic data in consecutive patients who were subjected to colposcopic evaluation at the colposcopy clinic at the First Department of Obstetrics and Gynaecology, University of Milan (Milan, Italy). A total of 177 women were subjected to colposcopy because of a single routine Pap smear showing mild dyskaryosis. A structured interview, sampling for HPV testing for the detection of viral DNA by hybrid capture methodology, and colposcopic evaluation with cervical biopsies were performed for each subject. The accuracies of molecular hybridization for HPV and of the classification model based on the demographic and lifestyle variables in predicting patients with histologically high-grade cervical intraepithelial lesions were measured. The classification model based on the demographic and lifestyle variables showed comparable results with molecular hybridization for HPV (specificity, 0.75 versus 0.73; sensitivity, 0.61 versus 0.67, respectively). The use of demographic and lifestyle variables appears to be a simple and economic possibility for triaging patients with mild dyskaryotic smears in a screening program.

Adult↗
PubMed1997

Effect of parity and age at delivery on breast cancer risk in Slovenian women aged 25-54 years.

In 1988, a case-control study on breast cancer and oral contraceptives with 624 cases and 624 matched controls in the age range 25-54 years was undertaken in Slovenia. This analysis assesses the relationship between parity and breast cancer risk: the relative importance of age at first birth, age at subsequent births and total parity. We also evaluate whether a dual effect of an increased risk immediately after childbirth followed by a long-term benefit exists. Three logistic regression models were used. Age at first delivery is an important breast cancer risk factor: among parous women it was associated with a 5.3% increase/year in the odds of breast cancer. Multiparity was not shown to be an independent risk factor. Age at subsequent deliveries was associated with a 1% increase in risk for every 1 year increase of age at any birth, but this contribution to the risk was not significant. In the analysis stratified by parity the most important influence is with the age at first birth. We find no evidence of an effect on the odds of breast cancer associated with the age at the second, or later, births. We do find that there is an increased risk associated with the birth of the first child followed by a longer term protective effect. A post-menopausal woman has a reduced breast cancer risk compared with a pre-menopausal woman of the same age, adjusting for the same number of deliveries and ages at these deliveries.

Adult↗
PubMed1997

Central venous catheters coated with minocycline and rifampin for the prevention of catheter-related colonization and bloodstream infections. A randomized, double-blind trial. The Texas Medical Center Catheter Study Group.

BACKGROUND: Central venous catheters are a principal source of nosocomial bloodstream infections, which are difficult to control. OBJECTIVE: To determine the efficacy of catheters coated with minocycline and rifampin in preventing catheter-related colonization and bloodstream infections. DESIGN: Multicenter, randomized clinical trial. SETTING: Five university-based medical centers. PATIENTS: 281 hospitalized patients who required 298 triple-lumen, polyurethane venous catheters. INTERVENTION: 147 catheters were pretreated with tridodecylmethyl-ammonium chloride and coated with minocycline and rifampin. Untreated, uncoated catheters (n = 151) were used as controls. MEASUREMENTS: Quantitative catheter cultures, blood cultures, and molecular typing of organisms to determine catheter-related colonization and bloodstream infections. RESULTS: The group with coated catheters and the group with uncoated catheters were similar with respect to age, sex, underlying diseases, degree of immunosuppression, therapeutic interventions, and risk factors for catheter infections. Colonization occurred in 36 (26%) uncoated catheters and 11 (8%) coated catheters (P < 0.001). Catheter-related bloodstream infection developed in 7 patients (5%) with uncoated catheters and no patients with coated catheters (P < 0.01). Multivariate logistic regression analysis showed that coating catheters with minocycline and rifampin was an independent protective factor against catheter-related colonization (P < 0.05). No adverse effects related to the coated catheters or antimicrobial resistance were seen. An estimate showed that the use of coated catheters could save costs. CONCLUSIONS: Central venous catheters coated with minocycline and rifampin can significantly reduce the risk for catheter-related colonization and bloodstream infections. The use of these catheters may save costs.

Adolescent↗
PubMed1997

Mealtime difficulties in a home for the aged: not just dysphagia.

A mealtime screening tool was administered to 349 residents of a home for the aged to determine the prevalence of mealtime difficulties including, but not limited to, dysphagia. Mealtime difficulties, as assessed during a single meal observation of each resident, were documented in 87% of these individuals. Though 68% exhibited signs of dysphagia, 46% had poor oral intake, 35% had positioning problems, and 40% exhibited challenging behaviors. An increased prevalence of mealtime difficulties was related to both the presence and degree of cognitive impairment. Oral intake was best among residents with severe cognitive impairment, many of whom received partial to total feeding assistance. In contrast, poor oral intake was associated with mild-moderate cognitive impairment, pointing to a need for more aggressive intervention with this group. The results clearly demonstrate that the prevalence of a wide range of eating-related problems far exceeds accepted estimates of dysphagia alone and support a multidisciplinary approach to mealtime interventions for the institutionalized elderly. Additionally, the magnitude of problems identified has implications for both resource and staff-training requirements in long-term care facilities.

Aged↗