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.

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.

Feasibility study of a head and neck (upper aero-digestive tract) cancer examination.

Nearly all of the requirements for a cancer screening program can be met for head and neck--upper aero-digestive tract (UADT)--cancers. These UADT squamous cancers have a clearly definable high-risk group (smokers, greater than or equal to 40 yr), known etiology (tobacco and alcohol), identifiable premalignant lesions, a high prevalence rate worldwide, and high curability with "early" diagnosis. However, a need exists for an efficient detection examination suitable for physicians and dentists alike. Such an examination was designed and field tested as a feasibility study. The examination consisted of a six-step, dentist-oriented, site-targeted, 10-minute procedure, including the use of a fiberoptic pharyngoscope. Two practicing dentists were instructed in the procedure and used it on a randomly selected, high-risk Health America, Inc.--Park DuValle Community Health Center population, who were voluntary responders to a questionnaire and a phone call. Analysis of results showed easy and reproducible teachability, a high degree of acceptance by dentists and examinees, accuracy, and low cost. Associated findings were the following: Of 6,206 respondents, ages 40 and over, 27% were current smokers; 29% were ex-smokers; and 33% never smoked. Of invited current and ex-smokers, ages 40 and over, 51% appeared for a single examination. Compliance emerged as the major problem. The feasibility demonstrated in this study appears to justify a larger, controlled investigation.

Low-fiber intake as an etiologic factor in cancer of the colon.

A case-control dietary study of 198 patients with cancer of the colon and two matched control groups demonstrated a significantly lower fiber consumption frequency among the cancer patients. This difference was not confined to a few items. Of the 73 items on the fiber list, 61 were eaten less often by the cancer patient than by a neighborhood control, and 57 were consumed less frequently than by a surgical control. These findings support the hypothesis that low-residue foods play an etiologic role in colon carcinogenesis. A mechanism related to the possible potential carcinogenic properties of degraded biliary compounds may be implicated.

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.

Geometry, growth rates, and duration of cancer and carcinoma in situ of the breast before detection by screening.

The purpose of this study is to report the time elapsing between the moment a breast cancer reaches threshold size that would permit detection and the size at actual detection defined as sojourn time (STt) using data from the Breast Cancer Detection and Demonstration Project (Louisville data and reported composite data from 27 centers) by dividing prevalence rates by incidence rates. The number of cellular generations (n) required to produce cancers of different volumes was calculated at threshold (nt), at detection (nd), and the difference between the two (nd - nt). By dividing the difference (nd - nt) into STt, the average actual or net tumor volume doubling time (DTact) in this interval have been estimated. The STt value for carcinoma in situ was 557 and for cancer it was 538. At ages 35-39, STt ranged from 365-456 days, by ages 70-74, 942-1383 days. The average DTact similarly varied with age, carcinoma in situ, cancer with negative axillary nodes, and cancer with positive axillary nodes over a range of 28-732 days (95% confidence). The estimated DTact in the predetectable period was manyfold less than the DTact measured for mammographically visible cancers, in keeping with the predictions of decelerating growth. Models of the cytokinetic and clinical behavior of breast cancer are discussed.

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.

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.

Radiographic measurement of topical corticosteroid-induced atrophy.

Soft tissue x-ray techniques were used to measure skin thickness as influenced by the chronic usage of topical corticosteroids. In a double-blind study commercial preparations of 1% hydrocortisone (HC), 0.1% triamcinolone acetonide (TA), and a placebo cream were compared for their ability to produce atrophy in normal human forearm skin. After 8 weeks of topical application of the creams, only TA produced clinically apparent atrophy. The average percent decreases in skin thickness measured after 8 weeks of treatment with placebo, HC, or TA were 6.0%, 6.0%, and 17.1%, respectively. During the first week after cessation of treatment the clinical appearance of the skin began to improve and by 1 month all treated skin areas had essentially returned to pretreatment thickness.

Use of serum bile acids in the identification of vinyl chloride hepatotoxicity.

Most previous studies proposing serum bile acids as indicators of hepatic function have been performed in hospitalized patients in whom overt symptomatic liver disease was present. The ability of fasting levels of serum bile acids to identify mild, clinically inapparent chemical liver injury in an occupational setting was compared with that of indocyanine green clearance and routine biochemical liver tests in 67 asymptomatic chemical workers in whom liver biopsies had been performed for medical indications. Histologically, 15 were found to have chemical liver injury, 27 had nonchemical liver disease, and 25 were normal. Two serum bile acids, cholylglycine and conjugates of cholic acid, were determined by radioimmunoassay, using 466 "normal" males from the same worker cohort as a reference range. The geometric mean concentrations of cholylglycine in patients with chemical liver injury, patients with nonchemical liver disease, and normal subjects were 47.9, 19.1, and 20.0 micrograms/dl, respectively (p = 0.036 by analysis of variance). Conjugates of cholic acid showed similar differences (p = 0.027), as did indocyanine green clearance with mean half-life of 4.2, 3.2, and 3.3 minutes in the three biopsy subgroups, respectively (p = 0.043). Such differences were not observed for biochemical liver tests. The fasting level of serum bile acids provided high specificity but lower sensitivity in the detection of all types of liver disease. However, serum bile acids and indocyanine green clearance provided a higher specificity and sensitivity for chemical liver injury than for nonchemical liver disease. An index of average exposure to vinyl chloride was significantly greater in the subgroup with chemical liver injury than in the other two groups, further supporting the association of chemical type injury with impaired anion uptake. These data identify the fasting level of serum bile acids as a clinically usable indicator of early chemical injury in chemically exposed asymptomatic worker populations with liver dysfunction. Further investigation is needed in other occupational hepatotoxic environments to determine if this association is limited to vinyl monomer type injury.

Failure-to-thrive: a study in a primary care setting. Epidemiology and follow-up.

A cohort of 312 children followed in three rural primary care centers was studied. All cases of failure-to-thrive were identified (30) and compared to the remainder of the group. With the use of data from medical records, children with history of failure-to-thrive were found to be significantly lighter and shorter than the remainder of the population in each of the first five years of life. More cases had family problems. No differences were found in demographic characteristics or chronic illnesses. In the second phase of the study, cases and an equal-sized control group, from the same social setting, matched for age, sex, mother's marital status, and family problems, were examined at 3 to 6 years of age to assess outcome. This included physical examination, the McCarthy Scale of Children's Abilities, a behavior questionnaire, and an interview to assess life events. Cases were lighter but not shorter than controls. No instances of occult organic disease causing failure-to-thrive were identified. No behavioral or developmental deficits could be attributed to the failure-to-thrive.

Comparison of direct and microslide pathology measurements of uveal melanomas.

Many investigators have shown that large cilio-choroidal melanomas are more likely to be associated with an unfavorable outcome than small tumors by using data retrieved and measured from pathology files. In the past, the measurement of largest tumor dimension (LTD) may not have been recorded at the time of the gross examination, because the significance of this observation was not appreciated. If this information is not available, authors can eliminate cases from their studies, take all their measurements directly from glass microslides, or combine clinical estimates of tumor size for some cases with gross measurements for others. To date, there has been no formal study to compare the measurement of tumor dimensions from glass microslides with measurements made at the time of gross examination by the pathologist. This study of 112 cilio-choroidal melanomas reveals that measurements of the LTD made from the glass microslide correlate with direct measurements taken from the cut surface of the globe at the time of sectioning. Additionally, measurements of the LTD from the glass microslide are at least as effective in predicting patient outcome as direct measurements. These findings suggest that measurements of the LTD from the glass microslide provide as much prognostic information as direct measurements if it is known that the eye was cut to obtain representative sections of the tumor.

Computerized histologic assessment of malignant potential: a method for determining the prognosis of uveal melanomas.

The authors evaluated 50 cases of primary melanoma of the choroid and ciliary body. In each case, 100 cells were randomly selected from a single histologic slide, and on each cell computer-assisted measurements were made of 18 nuclear and nucleolar features. Means and standard deviations were calculated for each of these features in each tumor. Thirteen calculated variables (six means and seven standard deviations) were found to correlate significantly with patient mortality following enucleation. Standard deviations of statistically significant nuclear and nucleolar features demonstrated significantly greater correlation with mortality than the means of these features, thus confirming the great value of nuclear pleomorphism for predicting the malignant potential of uveal melanomas. Furthermore, when the standard deviation of the nucleolar circumference, a feature highly correlated with survival (P less than 0.00001), was combined with the measurement of the largest dimension of the tumor, linear discriminant analysis correctly predicted the clinical course of 88 per cent of cases.

Objective assessment of the malignant potential of intraocular melanomas with standard microslides stained with hematoxylin-eosin.

A method for extracting prognostic information from the cytologic details of intraocular melanomas was developed. With computer assistance, a technician measures the nucleolar area of 200 tumor cells randomly selected from a standard paraffin-embedded microsection stained with hematoxylin-eosin, a procedure that requires approximately 40 minutes with an apparatus that costs less than +30,000. Standard deviation of nucleolar area (SDNA), computed from these measurements, provides an objective assessment of nucleolar pleomorphism. Previous studies showed that second measurements of the same microsection or of the same tumor at different levels yield SDNA values that closely approximate the original measurements. The application of this method to 540 cases from three independent laboratories yielded a correlation of SDNA with death from tumor that was high (P much less than 0.001) and consistent among cases from all three sources. Thus, SDNA provides a clinically useful cytologic measure of the malignancy of intraocular melanomas and may ultimately prove valuable in the assessment of other types of tumors.

Urinary calcium excretion in relation to kidney function in the adult.

A study based on 55 hospital patients (age groups 40-59, 60-69, 70-79) demonstrated a significant correlation between the glomerular filtration rate (as expressed by endogenous creatinine clearance) and the mean urinary calcium concentration. Excluded were patients with thyroidal or hypophyseal disorders, osteoporosis, renal stones immobilizing conditions, or those treated with corticosteroids. The study patients had a normal fluid intake and did not receive any diuretics. The urinary calcium concentration test is less laborious and less liable to laboratory errors than the creatinine clearance test, which requires a 24-hour urine collection. Because of the gradual decrease in the glomerular filtration rate in the elderly, this test should be of value in geriatric practice.

Metastatic uveal melanoma. Correlation between survival time and cytomorphometry of primary tumors.

The length of survival time following enucleation was determined for 29 patients with primary malignant melanoma of the choroid and ciliary body who subsequently died of metastatic disease. Histologic sections of the 29 tumors were studied by standard light microscopic techniques and computerized morphometry. The largest diameter of each tumor was measured on the 37% formaldehyde-fixed, paraffin-embedded slides; a cell type was assigned to each tumor on the basis of histologic study, using the modified Callender cell-type classification system; and inverse standard deviation of the nucleolar area (ISDNA) was determined for each tumor by computerized morphometric analysis. The observed death-order of these patients was then compared with the death-order predicted by ranking cases in ascending order of age at treatment, size of tumor, cell type, and ISDNA. Using rank-order correlation coefficient tests, only the correlation between ISDNA rank-order and observed death-order was found to be statistically significant. We believe that the limitations of the modified Callender cell-type classification system in predicting length of survival time following enucleation are related to the relatively few categories (four) in which to classify tumors, whereas the ISDNA represents a continuous spectrum of unlimited categories. As such, ISDNA can be more discriminant in selecting tumors of high malignant potential.

Enucleation vs cobalt plaque radiotherapy for malignant melanomas of the choroid and ciliary body.

Clinical risk factors were assessed prospectively in a nonrandomized concurrent observational study of 237 patients with posterior uveal malignant melanoma. One hundred forty of these patients were treated with enucleation, and 97 underwent cobalt plaque radiotherapy. Tumor size and location of the anterior tumor margin proved to be the most significant clinical risk factors for death from metastatic melanoma. When Cox proportional hazards modeling was used to adjust for recognized intergroup differences in risk factors, the effect of therapy (enucleation vs cobalt plaque radiotherapy) on survival time was not statistically significant. We discuss the implications of this study for a randomized clinical trial of enucleation vs cobalt plaque therapy or comparable forms of irradiation.

Thickness as prognostic aid in upper aerodigestive tract cancer.

A retrospective review of records and microscopic slides was carried out on 151 patients, encompassing nine specific upper aerodigestive tract cancer sites, correlating depth of invasion with node metastases and outcome. In this preliminary descriptive study, thickness was found to be more closely related to node metastasis and to survival than was surface diameter in middle-stage tumors, particularly in tongue, floor of the mouth, buccal mucosa, gum, and soft palate sites. Thickness, depth of penetration, and bone involvement appear to represent the degree of general tumor aggressiveness better than does surface extent. A substitution of thickness measurement for surface diameter (T) in the present TNM staging system is suggested.