Bioethics consultation practices and procedures: a survey of a large Canadian community of practice.

The literature fails to reflect general agreement over the nature of the services and procedures provided by bioethicists, and the training and core competencies this work requires. If bioethicists are to define their activities in a consistent way, it makes sense to look for common ground in shared communities of practice. We report results of a survey of the services and procedures among bioethicists affiliated with the University of Toronto Joint Centre for Bioethics (JCB). This is the largest group of bioethicists working in healthcare organizations in Canada. The results suggest there are many common services and procedures of JCB bioethicists. This survey can serve as a baseline for further exploration of the work of JCB bioethicists. Common practices exist with respect to the domains of practice, individual reporting relationships, service availability within business hours and the education and training of the bioethicist.

How young is too young to be a living donor?

Assessing people in adolescence and early adulthood who wish to become living organ donors (LDs) provides unique challenges. In several Canadian provinces, 16-year-old can legally consent to living organ donation. While the World Health Organization states that adolescence corresponds roughly to the ages of 10-19 years, parts of the brain associated with judgment continue to develop into the mid-20s. Therefore, it is legally possible for some young people to donate organs before their capacity to judge the benefits and risks of surgery has fully matured. Potential young living donors (YLDs) may be financially and/or psychologically dependent on their recipients (e.g. parents), which can make it difficult to determine if the YLD's donation is voluntary. This paper suggests ways to manage three ethical challenges in the use of young people as LDs: (1) determining the YLD's ability to appreciate the consequences of living organ donation, (2) determining whether the YLD's donation is voluntary and (3) evaluating the unique risks and benefits to the YLD. We conclude that there are compelling ethical reasons to offer the opportunity of living donation to selected young people. A thorough and fair evaluation process can address social, emotional and developmental issues associated with YLDs.

Familial breast cancer screening reveals an alteration in the RAP80 UIM domain that impairs DNA damage response function.

Germline mutations in two major susceptibility genes, BRCA1 and BRCA2, account for nearly 20% of familial breast cancers. A majority of the remaining genetic factors involved in heritable breast cancer susceptibility are, however, unknown. Recently, a new BRCA1-interacting protein, receptor associated protein 80 (RAP80), was identified. RAP80 plays an important role in BRCA1-mediated DNA damage responses (DDRs) by recruiting BRCA1 to DNA double-strand breaks (DSBs). A comprehensive screening of DNA from affected index cases of 112 BRCA1/BRCA2 mutation-negative Finnish breast cancer families revealed altogether 10 alterations in RAP80, one of which, c.241-243delGAA, resulted in a single glutamic acid deletion at residue 81 in a highly conserved region of ubiquitin interaction motif 1. The resultant delE81 protein product displayed significantly reduced ubiquitin binding and DSB localization. Expression of the RAP80 delE81 allele impaired both BRCA1 and ABRA1 DSB recruitment, thus compromising BRCA1-mediated DDR signaling. Compared with wild-type RAP80, expression of the delE81 allele was associated with a significant increase in cytogenetically detectable chromosomal aberrations, particularly chromatid breaks. Although evidently quite rare, these results suggest that critical constitutional mutations in RAP80 abrogate DDR function and may be involved in genetic predisposition to cancer.

Telomeres, crisis and cancer.

Eukaryotic chromosomes terminate in specialized nucleic acid-protein complexes known as telomeres. Disruption of telomere structure by erosion of telomeric DNA or loss of telomere binding protein function activates a signal transduction program that closely resembles the cellular responses generated upon DNA damage. Telomere dysfunction in turn induces a permanent proliferation arrest known as senescence. Senescence is postulated to perform a tumor suppressor function by limiting cellular proliferative capacity, thus imposing a barrier to cellular immortalization. Genetic or epigenetic silencing of components of the DNA damage pathway, allows cells to proliferate beyond senescence limits. However, these cells eventually reach a stage of extreme telomere dysfunction known as crisis that is characterized by cell death and the concomitant appearance of cytogenetic abnormalities. Telomeric crisis produces significant chromosomal instability, a hallmark of human cancer, and may thus be relevant to carcinogenesis by increasing the occurrence of genetic alterations that would favor neoplastic transformation. The following review examines the relationship of telomere function during crisis in accelerating chromosomal instability and cancer.

Mitogen stimulation cooperates with telomere shortening to activate DNA damage responses and senescence signaling.

Replicative senescence is induced by critical telomere shortening and limits the proliferation of primary cells to a finite number of divisions. To characterize the activity status of the replicative senescence program in the context of cell cycle activity, we analyzed the senescence phenotypes and signaling pathways in quiescent and growth-stimulated primary human fibroblasts in vitro and liver cells in vivo. This study shows that replicative senescence signaling operates at a low level in cells with shortened telomeres but becomes fully activated when cells are stimulated to enter the cell cycle. This study also shows that the dysfunctional telomeres and nontelomeric DNA lesions in senescent cells do not elicit a DNA damage signal unless the cells are induced to enter the cell cycle by mitogen stimulation. The amplification of senescence signaling and DNA damage responses by mitogen stimulation in cells with shortened telomeres is mediated in part through the MEK/mitogen-activated protein kinase pathway. These findings have implications for the further understanding of replicative senescence and analysis of its role in vivo.

Telomere dysfunction alters the chemotherapeutic profile of transformed cells.

Telomerase inhibition has been touted as a novel cancer-selective therapeutic goal based on the observation of high telomerase levels in most cancers and the importance of telomere maintenance in long-term cellular growth and survival. Here, the impact of telomere dysfunction on chemotherapeutic responses was assessed in normal and neoplastic cells derived from telomerase RNA null (mTERC(-/-)) mice. Telomere dysfunction, rather than telomerase per se, was found to be the principal determinant governing chemosensitivity specifically to agents that induced double-stranded DNA breaks (DSB). Enhanced chemosensitivity in telomere dysfunctional cells was linked to therapy-induced fragmentation and multichromosomal fusions, whereas telomerase reconstitution restored genomic integrity and chemoresistance. Loss of p53 function muted the cytotoxic effects of DSB-inducing agents in cells with telomere dysfunction. Together, these results point to the combined use of DSB-inducing agents and telomere maintenance inhibition as an effective anticancer therapeutic approach particularly in cells with intact p53-dependent checkpoint responses.

Short dysfunctional telomeres impair tumorigenesis in the INK4a(delta2/3) cancer-prone mouse.

Maintenance of telomere length is predicted to be essential for bypass of senescence and crisis checkpoints in cancer cells. The impact of telomere dysfunction on tumorigenesis was assessed in successive generations of mice doubly null for the telomerase RNA (mTR) and the INK4a tumor suppressor genes. Significant reductions in tumor formation in vivo and oncogenic potential in vitro were observed in late generations of telomerase deficiency, coincident with severe telomere shortening and associated dysfunction. Reintroduction of mTR into cells significantly restored the oncogenic potential, indicating telomerase activation is a cooperating event in the malignant transformation of cells containing critically short telomeres. The results described here demonstrate that loss of telomere function in a cancer-prone mouse model possessing intact DNA damage responses impairs, but does not prevent, tumor formation.

Telomerase reverse transcriptase gene is a direct target of c-Myc but is not functionally equivalent in cellular transformation.

The telomerase reverse transcriptase component (TERT) is not expressed in most primary somatic human cells and tissues, but is upregulated in the majority of immortalized cell lines and tumors. Here, we identify the c-Myc transcription factor as a direct mediator of telomerase activation in primary human fibroblasts through its ability to specifically induce TERT gene expression. Through the use of a hormone inducible form of c-Myc (c-Myc-ER), we demonstrate that Myc-induced activation of the hTERT promoter requires an evolutionarily conserved E-box and that c-Myc-ER-induced accumulation of hTERT mRNA takes place in the absence of de novo protein synthesis. These findings demonstrate that the TERT gene is a direct transcriptional target of c-Myc. Since telomerase activation frequently correlates with immortalization and telomerase functions to stabilize telomers in cycling cells, we tested whether Myc-induced activation of TERT gene expression represents an important mechanism through which c-Myc acts to immortalize cells. Employing the rat embryo fibroblast cooperation assay, we show that TERT is unable to substitute for c-Myc in the transformation of primary rodent fibroblasts, suggesting that the transforming activities of Myc extend beyond its ability to activate TERT gene expression and hence telomerase activity.

Expression of mouse telomerase reverse transcriptase during development, differentiation and proliferation.

We have identified the mouse telomerase reverse transcriptase component (mTERT) and demonstrate both substantial sequence homology to the human ortholog (hTERT), and the presence of reverse transcriptase and telomerase specific motifs. Furthermore, we show functional interchangeability with hTERT in in vitro telomerase reconstitution experiments, as mTERT produces strong telomerase activity in combination with the human telomerase RNA component hTR. The mouse TERT is widely expressed at low levels in adult tissues, with greatest abundance during embryogenesis and in adult thymus and intestine. The mTERT component mRNA levels were regulated during both differentiation and proliferation, while mTR levels remained constant throughout both processes. Comparison of mTERT and mTR levels to telomerase activity indicates that mTERT expression is more tightly linked to the regulation of telomerase activity during these processes than is mTR. In contrast to the situation in human cell cultures, mTERT transcript levels are present at readily detectable levels in primary cultured cells and are not upregulated following crisis. The widespread expression of mTERT in primary cells and mouse tissues could explain the increased frequency of spontaneous immortalization of mouse cells in culture and tumorigenesis in vivo.

Urinary cotinine and parent history (questionnaire) as indicators of passive smoking and predictors of lower respiratory illness in infants.

Studies of the effects of passive smoking on lower respiratory illness (LRI) have relied on questionnaires to measure exposure. We studied the association between two measures of passive smoking and the incidence of acute LRI in infants. We analyzed data from a community-based cohort study of respiratory illness during the first year of life in North Carolina. The incidence of LRI was determined by telephone calls at 2-week intervals. Environmental, demographic, and psychosocial risk factors for LRI were measured during home interviews. Tobacco smoke exposure was measured as the mean number of cigarettes smoked per day in the infant's presence. Smoke absorption by the infants was measured by the urinary cotinine/ creatinine ratio. Of the 485 infants in the study, 325 (67%) had telephone follow-up and at least two home interviews. In bivariate analyses, reported tobacco smoke exposure and urinary cotinine were associated with LRI. Only the association between reported exposure and LRI remained significant after adjusting for confounders, [adjusted incidence of LRI (episodes/child-year) non-exposed: 0.6; < or = 10 cigarettes/day: 0.9 (RR 1.5, 95% CI: 1.1, 2.0); > 10 cigarettes/day: 1.3 (RR 2.2, 95% CI: 1.3, 3.8)]. We conclude that infants reportedly exposed to tobacco smoke have an increased incidence of LRI. There are differences between questionnaire and biochemical measures of passive smoking. Urinary cotinine will not necessarily improve the validity of studies of the relationship of passive smoking to LRI in infants.

Evaluation of asymptomatic microhematuria.

OBJECTIVES: The purpose of this study was to evaluate a comprehensive urine cytodiagnostic assay to assist in localizing the site of origin and the etiology of asymptomatic microhematuria. This analysis, which assesses various qualitative and quantitative aspects of the voided urine, is compared simultaneously with controls obtained from the established routine urologic evaluation. METHODS: One hundred consecutive subjects who presented solely for the evaluation of asymptomatic microhematuria were evaluated by the established routine urologic evaluation and a refined urine cytodiagnostic assay. For the purpose of this study, only calculi and neoplasms were considered significant findings. RESULTS: The incidence of significant urologic disease was 13% (3 renal neoplasms, 2 urothelial bladder carcinomas, and 8 urinary calculi). The refined urine cytodiagnostic assay identified both uroepithelial vesical neoplasms, 7 of the 8 urinary calculi, and none of the 3 renal neoplasms. The presence of dysmorphic urinary red blood cells (RBCs) and RBC casts was strongly suggestive of renal parenchymal bleeding. Overall, 43 of 44 subjects (98%) with dysmorphic RBCs and RBC casts failed to demonstrate any significant urologic etiology. CONCLUSIONS: These preliminary results suggest that the refined cytodiagnostic urine assay may be helpful in distinguishing whether a given patient's microhematuria is of a significant urologic or a renal parenchymal cause. The addition of this specialized urinalysis may prove a useful adjunct in improving the diagnostic yield in patients with asymptomatic microhematuria.

Effects of high-intensity strength training on multiple risk factors for osteoporotic fractures. A randomized controlled trial.

OBJECTIVE: To determine how multiple risk factors for osteoporotic fractures could be modified by high-intensity strength training exercises in postmenopausal women. DESIGN: Randomized controlled trial of 1-year duration. SETTING: Exercise laboratory at Tufts University, Boston, Mass. POPULATION: Forty postmenopausal white women, 50 to 70 years of age, participated in the study; 39 women completed the study. The subjects were sedentary and estrogen-deplete. INTERVENTIONS: High-intensity strength training exercises 2 days per week using five different exercises (n = 20) vs untreated controls (n = 19). MAIN OUTCOME MEASURES: Dual energy x-ray absorptiometry for bone status, one repetition maximum for muscle strength, 24-hour urinary creatinine for muscle mass, and backward tandem walk for dynamic balance. RESULTS: Femoral neck bone mineral density and lumbar spine bone mineral density increased by 0.005 +/- 0.039 g/cm2 (0.9% +/- 4.5%) (mean +/- SD) and 0.009 +/- 0.033 g/cm2 (1.0% +/- 3.6%), respectively, in the strength-trained women and decreased by -0.022 +/- 0.035 g/cm2 (-2.5% +/- 3.8%) and -0.019 +/- 0.035 g/cm2 (-1.8% +/- 3.5%), respectively, in the controls (P = .02 and .04). Total body bone mineral content was preserved in the strength-trained women (+2.0 +/- 68 g; 0.0% +/- 3.0%) and tended to decrease in the controls (-33+77 g; -1.2% +/- 3.4%, P = .12). Muscle mass, muscle strength, and dynamic balance increased in the strength-trained women and decreased in the controls (P = .03 to < .001). CONCLUSIONS: High-intensity strength training exercises are an effective and feasible means to preserve bone density while improving muscle mass, strength, and balance in postmenopausal women.

Evaluation of a home-based intervention program to reduce infant passive smoking and lower respiratory illness.

We conducted a randomized controlled trial to determine whether a home-based intervention program could reduce infant passive smoking and lower respiratory illness. The intervention consisted of four nurse home visits during the first 6 months of life, designed to assist families to reduce the infant's exposure to tobacco smoke. Among the 121 infants of smoking mothers who completed the study, there was a significant difference in trend over the year between the intervention and the control groups in the amount of exposure to tobacco smoke; infants in the intervention group were exposed to 5.9 fewer cigarettes per day at 12 months. There was no group difference in infant urine cotinine excretion. The prevalence of persistent lower respiratory symptoms was lower among intervention-group infants of smoking mothers whose head of household had no education beyond high school: intervention group, 14.6%; and controls, 34.0%.

Lower respiratory illness in infants and low socioeconomic status.

OBJECTIVES: Infants from families of low socioeconomic status are said to suffer higher rates of lower respiratory illness, but this assertion has not been carefully examined. METHODS: We studied the frequency and determinants of lower respiratory illness in infants of different socioeconomic status (n = 393) by analyzing data from a community-based cohort study of respiratory illness during the first year of life in central North Carolina. RESULTS: The incidence of lower respiratory illness was 1.41 in the low socioeconomic group, 1.26 in the middle group, and 0.67 in the high group. The prevalence of persistent respiratory symptoms was 39% in infants in the low socioeconomic group, 24% in infants in the middle group, and 14% in infants in the high group. The odds of persistent respiratory symptoms in infants of low and middle socioeconomic status were reduced after controlling for environmental risk factors for lower respiratory illness. Enrollment in day care was associated with an increased risk of persistent symptoms among infants of high but not low socioeconomic status. CONCLUSIONS: Infants of low socioeconomic status are at increased risk of persistent respiratory symptoms. This risk can be partly attributed to environmental exposures, most of which could be changed.

Passive smoking during the first year of life.

BACKGROUND AND PURPOSE: A description of passive smoking during the first year of life might assist planning preventive efforts. METHODS: Changes in the ecology of passive smoking were investigated in a sample of infants in central North Carolina followed from birth to one year of age. RESULTS: The prevalence of tobacco smoke absorption, indicated by excretion of cotinine, increased from 53 percent to 77 percent (95% CI of difference: 14, 35) during the first year of life. Most infants (92 percent) excreting cotinine at three weeks of age were also excreting it at one year. Moreover, 61 percent of infants not excreting cotinine at age three weeks were excreting it at one year. This increase reflected an increased exposure to household and, particularly, nonhousehold sources of smoke; the proportion of infants exposed to nonhousehold smokers increased from 14 percent to 36 percent. CONCLUSIONS: These findings suggest that prevention of the onset of passive smoking should begin very early.

Validity of the clinical alert on breast cancer.

In May 1988, the National Cancer Institute issued a clinical alert calling for the routine use of systemic adjuvant therapy for all node-negative breast cancers. Subsequent review of the data that the National Cancer Institute used as a basis for its endorsement revealed several limitations, including failure to consider cost-benefit ratios and failure to exclude late toxicities. The authors conclude that the issuance of the release was premature and that it does not attempt to balance the slight lengthening of disease-free survival against the overall population costs. It is suggested that physicians individually assess the potential merits of such a treatment regimen in each of their patients with node-negative breast cancer.

Autoinoculated palmar pustules in neonatal candidiasis.

A 2-week-old infant had grouped pustules on the right hand, wrist, and antecubital flexure that appeared after the first week of life. The infant was seen repeatedly to suck the involved areas of the hand and wrist. Clinically typical candidiasis was noted in the oral cavity and the diaper area. Wright's-stained smears of pustular contents, potassium hydroxide preparations of pustular material, and scale from the diaper dermatitis confirmed the presence of pseudohyphae and budding yeasts in all the involved sites. This case demonstrates fairly typical manifestations of neonatal-onset candidiasis, with the unusual feature of unilateral upper extremity pustules that appeared to represent an autoinoculated cutaneous infection.

Ecology of passive smoking by young infants.

This study provides a detailed description of passive smoking by 433 infants (mean age 18 days) enrolled from a representative population of healthy neonates in central North Carolina during 1986 and 1987. Sixty-four percent (276) lived in households with smokers or had contact with nonhousehold smokers. During the week before data collection, two thirds (184) of these 276 infants reportedly had tobacco smoke produced in their presence. Seventy-five percent of smoking mothers smoked near their infants. The amount smoked by the mother near the infant correlated with the amount smoked near the infant by nonmaternal smokers. Cotinine, an indicator of smoke absorption, was found in the urine of 60% (258) of all study infants. The amount smoked in the infant's presence, as well as the amount smoked farther away from the infant, especially by the mother, were the most significant correlates of the urine cotinine concentration. The results of this study suggest that efforts to reduce passive smoking in young infants should emphasize the importance of the mother's smoking behavior, smoke produced anywhere in the home, and household social influences on smoking behavior near the infant.

Breast cancer risk: a review of definitions and assessments of risk.

The histopathological and biochemical characteristics of cells and multicellular structure of benign and malignant breast changes have highly significant implications as to the risk of acquiring and dying of breast cancer. Consequently, every breast biopsy merits highly specific histopathological characterization as well as assay for hormone receptors. Certain aspects of a woman's personal and family history may be associated with increased or decreased risk. Clinical application of these variables to the prediction of future outcome requires an understanding of the definitions of risk. These definitions must then be applied appropriately when assessing risk. The definition of risk used must be explicitly stated and consistently used. Provided is a review of the definitions of risk and the risk of acquiring breast cancer according to age, family history, and histopathological characteristics of benign breast biopsies. The highly variable relative risk of dying from breast cancer when diagnosed is also reviewed.