Changes in primary care provider utilization by phase of care for women diagnosed with breast cancer: a CanIMPACT longitudinal cohort study

BACKGROUND

Primary care providers (PCPs) have always played an important role in cancer diagnosis. There is increasing awareness of the importance of their role during treatment and survivorship. We examined changes in PCP utilization from pre-diagnosis to survival for women diagnosed with breast cancer, factors associated with being a high user of primary care, and variation across four Canadian provinces.

METHODS

The cohorts included women 18+ years of age diagnosed with stage I-III invasive breast cancer in years 2007-2012 in British Columbia (BC), Manitoba (MB), Ontario (ON), and Nova Scotia (NS) who had surgery plus adjuvant chemotherapy and were alive 30+ months after diagnosis (N = 19,589). We compared the rate of PCP visits in each province across phases of care (pre-diagnosis, diagnosis, treatment, and survival years 1 to 4).

RESULTS

PCP use was greatest during treatment and decreased with each successive survival year in all provinces. The unadjusted difference in PCP use between treatment and pre-diagnosis was most pronounced in BC where PCP use was six times higher during treatment than pre-diagnosis. Factors associated with being a high user of primary care during treatment included comorbidity and being a high user of care pre-diagnosis in all provinces. These factors were also associated with being a higher user of care during diagnosis and survival.

CONCLUSIONS

Contrary to the traditional view that PCPs focus primarily on cancer prevention and early detection, we found that PCPs are involved in the care of women diagnosed with breast cancer across all phases of care.

Assessing the impact of mailing self-sampling kits for human papillomavirus testing to unscreened non-responder women in Manitoba

Background

CervixCheck, Manitoba's cervical cancer screening program, conducted a pilot study to assess whether screening participation could be improved in unscreened women by offering a mailed self-sampling kit for human papillomavirus (hpv) testing instead of a Pap test.

Methods

In a prospective cohort study design, a sample of unscreened women (n = 1052) who had been sent an invitation letter from CervixCheck in the past but who did not respond were randomized to either an intervention group or a control group. The intervention group received a mailed hpv self-sampling kit; the control group received no additional communication. Returned hpv self-sampling swabs were analyzed by a provincial laboratory. After 6 months, screening participation in the two study groups was compared using a logistic regression model adjusted for age and area of residence (urban or rural). Secondary outcomes included hpv positivity, specimen inadequacy, compliance with follow-up, and time to colposcopy.

Results

Screening participation was significantly higher in the intervention group than in the control group (n = 51, 9.6%, vs. n = 13, 2.5%; odds ratio: 4.7; 95% confidence interval: 2.56 to 8.77). Geographic area of residence (urban or rural) and age were not statistically significant.

Conclusions

The study demonstrated that hpv self-sampling kits can enhance screening participation in unscreened non-responder women in the setting of an organized screening program. Next steps should include additional research to determine the best implementation strategy for hpv self-sampling in Manitoba.

Measuring colposcopy quality in Canada: development of population-based indicators

Background

Colposcopy is a key part of cervical cancer control. As cervical cancer screening and prevention strategies evolve, monitoring colposcopy performance will become even more critical. In the present paper, we describe population-based colposcopy quality indicators that are recommended for ongoing measurement by cervical cancer screening programs in Canada.

Methods

The Pan-Canadian Cervical Cancer Screening Network established a multidisciplinary expert working group to identify population-based colposcopy quality indicators. A systematic literature review was conducted to ascertain existing population and program-level colposcopy quality indicators. A systems-level cervical cancer screening pathway describing each step from an abnormal screening test, to colposcopy, and back to screening was developed. Indicators from the literature were assigned a place on the pathway to ensure that all steps were measured. A prioritization matrix scoring system was used to score each indicator based on predetermined criteria. Proposed colposcopy quality indicators were shared with provincial and territorial screening programs and subsequently revised.

Results

The 10 population-based colposcopy quality indicators identified as priorities were colposcopy uptake, histologic investigation (biopsy) rate, colposcopy referral rate, failure to attend colposcopy, treatment frequency in women 18-24 years of age, re-treatment proportion, colposcopy exit-test proportion, histologic investigation (biopsy) frequency after low-grade Pap test results, length of colposcopy episode of care, and operating room treatment rate. Two descriptive indicators were also identified: colposcopist volume and number of colposcopists per capita.

Summary

High-quality colposcopy services are an essential component of provincial cervical cancer screening programs. The proposed quality and descriptive indicators will permit colposcopy outcomes to be compared between provinces and across Canada so as to identify opportunities for improving colposcopy services.

Kenyan Youth Understanding of Cancer, Cancer Risk and Cancer Prevention: An Ethnographic Study

Background: Cancer incidence and mortality continues to rise worldwide including in Kenya. Among the groups that are likely to get cancer in future are Kenyan youth that engage in behavior that can increase their lifetime cancer risk. Despite this awareness, little is known about Kenyan youth's understanding of cancer, cancer risk, and cancer prevention. Such awareness is needed to inform germane cancer prevention and health promotion initiatives. Aim: The purpose of this ethnographic study was to explore Kenyan youth's understanding of cancer, cancer risk, and cancer prevention. Methods: Fifty-three youth (ages 12-19) took part in individual interviews and focus group discussions. Results: In their conceptualization of cancer, youth described cancer in ways that are grouped into two themes: there is no other disease like it and lay understanding through metaphors. In their conceptualization of cancer risk, youth described cancer in ways that are grouped as cancer risk as lifestyle factors and the process of risk perception. Finally, in conceptualization of cancer prevention, youth described cancer prevention in ways that are grouped into the following themes: avoiding cancer risk factors, avoiding peers who partake in risk factors, and being healthy. Conclusion: This study is the first of its kind to be conducted in Kenya and adds to the body of knowledge in this area. Despite limited cancer control plans, youth described the grim consequences of getting cancer, their chances of getting the disease, and proposed opportunities for prevention. The study results will create a platform for future cancer prevention research and health promotion programs in Kenya and other part of Africa.

PoreDesigner for tuning solute selectivity in a robust and highly permeable outer membrane pore

Monodispersed angstrom-size pores embedded in a suitable matrix are promising for highly selective membrane-based separations. They can provide substantial energy savings in water treatment and small molecule bioseparations. Such pores present as membrane proteins (chiefly aquaporin-based) are commonplace in biological membranes but difficult to implement in synthetic industrial membranes and have modest selectivity without tunable selectivity. Here we present PoreDesigner, a design workflow to redesign the robust beta-barrel Outer Membrane Protein F as a scaffold to access three specific pore designs that exclude solutes larger than sucrose (>360 Da), glucose (>180 Da), and salt (>58 Da) respectively. PoreDesigner also enables us to design any specified pore size (spanning 3-10 Å), engineer its pore profile, and chemistry. These redesigned pores may be ideal for conducting sub-nm aqueous separations with permeabilities exceeding those of classical biological water channels, aquaporins, by more than an order of magnitude at over 10 billion water molecules per channel per second.

Nanoscale Ion Pump Derived from a Biological Water Channel

Biological molecular machines perform the work of supporting life at the smallest of scales, including the work of shuttling ions across cell boundaries and against chemical gradients. Systems of artificial channels at the nanoscale can likewise control ionic concentration by way of ionic current rectification, species selectivity, and voltage gating mechanisms. Here, we theoretically show that a voltage-gated, ion species-selective, and rectifying ion channel can be built using the components of a biological water channel aquaporin. Through all-atom molecular dynamics simulations, we show that the ionic conductance of a truncated aquaporin channel nonlinearly increases with the bias magnitude, depends on the channel's orientation, and is highly cation specific but only for one polarity of the transmembrane bias. Further, we show that such an unusually complex response of the channel to transmembrane bias arises from mechanical motion of a positively charged gate that blocks cation transport. By combining two truncated aquaporins, we demonstrate a molecular system that pumps ions against their chemical gradients when subject to an alternating transmembrane bias. Our work sets the stage for future biomimicry efforts directed toward reproducing the function of biological ion pumps using synthetic components.

Multigene expression profile testing in breast cancer: is there a role for family physicians?

BACKGROUND

Family physicians (fps) play a role in aspects of personalized medicine in cancer, including assessment of increased risk because of family history. Little is known about the potential role of fps in supporting cancer patients who undergo tumour gene expression profile (gep) testing.

METHODS

We conducted a mixed-methods study with qualitative and quantitative components. Qualitative data from focus groups and interviews with fps and cancer specialists about the role of fps in breast cancer gep testing were obtained during studies conducted within the pan-Canadian canimpact research program. We determined the number of visits by breast cancer patients to a fp between the first medical oncology visit and the start of chemotherapy, a period when patients might be considering results of gep testing.

RESULTS

The fps and cancer specialists felt that ordering gep tests and explaining the results was the role of the oncologist. A new fp role was identified relating to the fp-patient relationship: supporting patients in making adjuvant therapy decisions informed by gep tests by considering the patient's comorbid conditions, social situation, and preferences. Lack of fp knowledge and resources, and challenges in fp-oncologist communication were seen as significant barriers to that role. Between 28% and 38% of patients visited a fp between the first oncology visit and the start of chemotherapy.

CONCLUSIONS

Our findings suggest an emerging role for fps in supporting patients who are making adjuvant treatment decisions after receiving the results of gep testing. For success in this new role, education and point-of-care tools, together with more effective communication strategies between fps and oncologists, are needed.

Interference-Free Detection of Genetic Biomarkers Using Synthetic Dipole-Facilitated Nanopore Dielectrophoresis

The motion of polarizable particles in a nonuniform electric field (i.e., dielectrophoresis) has been extensively used for concentration, separation, sorting, and transport of biological particles from cancer cells and viruses to biomolecules such as DNAs and proteins. However, current approaches to dielectrophoretic manipulation are not sensitive enough to selectively target individual molecular species. Here, we describe the application of the dielectrophoretic principle for selective detection of DNA and RNA molecules using an engineered biological nanopore. The key element of our approach is a synthetic polycationic nanocarrier that selectively binds to the target biomolecules, dramatically increasing their dielectrophoretic response to the electric field gradient generated by the nanopore. The dielectrophoretic capture of the nanocarrier-target complexes is detected as a transient blockade of the nanopore ionic current, while any nontarget nucleic acids are repelled from the nanopore by electrophoresis and thus do not interfere with the signal produced by the target's capture. Strikingly, we show that even modestly charged nanocarriers can be used to capture DNA or RNA molecules of any length or secondary structure and simultaneously detect several molecular targets. Such selective, multiplex molecular detection technology would be highly desirable for real-time analysis of complex clinical samples.

Recent trends in breast, cervical, and colorectal cancer screening test utilization in Canada, using self-reported data from 2008 and 2012

In Canada, self-reported data from the Canadian Community Health Survey 2008 and 2012 provide an opportunity to examine overall utilization of breast, cervical, and colorectal cancer screening tests for both programmatic and opportunistic screening. Among women 50-74 years of age, utilization of screening mammography was stable (62.0% in 2008 and 63.0% in 2012). Pap test utilization for women 25-69 years of age remained high and stable across Canada in 2008 and 2012 (78.9% in 2012). The percentage of individuals 50-74 years of age who reporting having at least 1 fecal test within the preceding 2 years increased in 2012 (to 23.0% from 16.9% in 2008), but remains low. Stable rates of screening mammography utilization (about 30%) were reported in 2008 and 2012 among women 40-49 years of age, a group for which population-based screening is not recommended. Although declining over time, cervical cancer screening rates were high for women less than 25 years of age (for whom screening is not recommended). Interestingly, an increased percentage of women 70-74 years of age reported having a Pap test. In 2012, a smaller percentage of women 50-69 years of age reported having no screening test (5.9% vs. 8.5% in 2008), and more women reported having the three types of cancer screening tests (19.0% vs. 13.2%). Efforts to encourage use of screening within the recommended average-risk age groups are needed, and education for stakeholders about the possible harms of screening outside those age groups has to continue.

Zum Mechanismus der Induktion nicotinabbauender Enzyme in Artbrobacter oxydans

Die Induktion der Enzyme Nicotin-oxidase, L-6-Hydroxynicotin-oxidase, D-6-Hydroxynicotinoxidase und Keton-oxidase in Arthrobacter oxydans durch die optischen Antipoden und das Racemat des Nicotins und 6-Hydroxynicotins wurde in Gegenwart einer leicht metabolisierbaren C- und N-Quelle untersucht. Die Induktion der beiden Schlüsselenzyme des Nicotinabbaus, L-6-Hydroxynicotin-oxidase und D-6-Hydroxynicotin-oxidase, erfolgte nicht absolut stereospezifisch durch die optischen Antipoden des Nicotins oder 6-Hydroxynicotins, jedoch stimulierten die D-Antipoden stark die Induktion von D-6-Hydroxynicotin-oxidase. Eine Nicotin- oder eine 6-Hydroxynicotin-racemase ließ sich nicht nachweisen. D,L-6-Amino-nicotin erwies sich als ein schwacher Inducer für die nicotinabbauenden Enzyme in Arthrobacter oxydans.

Während sich aus Wachstumsversuchen eine Koordination für alle vier Enzyme ergab, führte die kinetische Analyse der Induktion zu einer Aufteilung in die Gruppen Nicotin-oxidase, L-6-Hydroxynicotin-oxidase, Keton-oxidase und D-6-Hydroxynicotin-oxidase. Die Induktion wurde durch D-Chloramphenicol und durch Actinomycin C gehemmt.

Rectification of Ion Current in Nanopores Depends on the Type of Monovalent Cations: Experiments and Modeling

Rectifying nanopores feature ion currents that are higher for voltages of one polarity compared to the currents recorded for corresponding voltages of the opposite polarity. Rectification of nanopores has been found to depend on the pore opening diameter and distribution of surface charges on the pore walls as well as pore geometry. Very little is known, however, on the dependence of ionic rectification on the type of transported ions of the same charge. We performed experiments with single conically shaped nanopores in a polymer film and recorded current-voltage curves in three electrolytes: LiCl, NaCl, and KCl. Rectification degrees of the pores, quantified as the ratio of currents recorded for voltages of opposite polarities, were the highest for KCl and the lowest for LiCl. The experimental observations could not be explained by a continuum modeling based on the Poisson-Nernst-Planck equations. All-atom molecular dynamics simulations revealed differential binding between Li⁺, Na⁺, and K⁺ ions and carboxyl groups on the pore walls, resulting in changes to both the effective surface charge of the nanopore and cation mobility within the pore.

Changes in cervical cancer screening behavior for women attending Pap Test Week clinics

Objective

This retrospective study of all women who accessed the 2006 Manitoba Pap Test Week clinics was designed to determine factors associated with inadequate cervical cancer screening and changes in cervical cancer screening behavior.

Methods

Data were acquired using the CervixCheck Manitoba registry and an ancillary database of demographic information collected from clinic attendees.

Results

The study included 1124 women. Of these, 53% (n = 598) were under-screened (no Pap test in the previous 2 years) prior to accessing the clinics. Logistic regression analyses demonstrated that older age (odds ratio [OR] = 1.02, 95% confidence interval [CI] 1.01–1.03), no doctor (OR = 1.4, 95% CI 1.05–1.54), and living in Canada < 1 year (OR = 5.5, 95% CI 2.73–11.12) were associated with being under-screened prior to accessing the Pap Test Week clinics. Thirty-seven percent (n = 223) of under-screened women demonstrated improved screening status subsequent to the 2006 Pap Test Week (had a subsequent Papanicolaou [Pap] test performed within 2 years) and these women were more likely to live in an urban setting (P = 0.003), be younger (P < 0.001), originate outside Canada (P = 0.006), have lived in Canada for less than 1 year (P = 0.006), and have had an abnormal Pap test result in 2006 (P < 0.001). Previously under-screened women were less likely to become adequately-screened subsequent to 2006 if they had a Pap test performed at a Pap Test Week clinic compared to having a Pap test performed elsewhere (37% versus 60%, P < 0.001).

Conclusion

This study identified a subset of under-screened women accessing Pap Test Week clinics whose screening status might be most modifiable.

Corrigendum: A First Look at Participation Rates in Cervical Cancer Screening Programs in Canada

K. Decker and and the Pan-Canadian Cervical Cancer Screening Initiative: Monitoring Program Performance Working Group is to be added to the author list. [...]

A first look at participation rates in cervical cancer screening programs in Canada

In 2011, the Pan-Canadian Cervical Cancer Screening Initiative (PCCSI), supported by the Canadian Partnership Against Cancer, released Cervical Cancer Screening in Canada: Monitoring Program Performance 2006–2008 and for the first time presented information on 12 national quality indicators relating to provincial and territorial cervical cancer screening programs. [...]

Undetected factor VIII in a patient with type 3 von Willebrands disease mistaken as severe haemophilia A

von Willebrand disease (VWD) type 3 is a rare disorder characterized by absent or <0.1 UmL(-1) of ristocetin cofactor (VWF:RCo), and a very low level of factor VIII (FVIII:C). A total absence of FVIII:C has never been reported in type 3 VWD. This case illustrates the effect of severe von Willebrand factor (VWF) deficiency on the factor VIII level.

Utilization of recombinant activated factor VII in southern Ontario in 85 patients with and without haemophilia

Recombinant activated factor VII (rFVIIa) is licensed for the treatment of bleeding in individuals with haemophilia and inhibitors. The use of rFVIIa appears to be increasing, and an increase in unlicensed use is suspected. There are currently few data about the specific indications for its use. The aim of this study was to describe the patterns of utilization of rFVIIa. We performed a retrospective cohort study using rFVIIa infusion data collected prospectively and clinical data collected retrospectively. Patients were identified using a tracking system designed to account for use of all coagulation factor concentrates issued in southern Ontario. Between 1 January 2001 and 31 December 2005, 85 patients received rFVIIa. 1164 infusions were given (8246.4 mg). Haemophilia patients with inhibitors accounted for 82.9% of rFVIIa infused and represented 8.2% of patients. The total amount of rFVIIa used increased each year from 2001 to 2004 and then decreased in 2005. The total number of infusions of rFVIIa administered annually increased. Both on-label and off-label use of rFVIIa increased. The number of patients with haemophilia receiving rFVIIa remained small and constant. The number of patients receiving rFVIIa for off-label indications increased markedly. Most rFVIIa infusions were given for licensed indications; however, these infusions represented <10% of patients treated. Overall, the utilization of rFVIIa is increasing, mostly for approved indications; however, the number of patients being prescribed rFVIIa for off-label indications has increased. The tracking system used in this study is a valuable tool to describe ongoing utilization patterns of rFVIIa.

Trends in the utilization and wastage of coagulation factor concentrates: the application of a regional tracking programme

The Commission of Inquiry on the Blood System in Canada ('Krever Commission', 1997) recommended an active programme of surveillance for all blood products. To describe trends in the utilization of coagulation factor concentrates using a comprehensive factor tracking programme. Between 2001 and 2004 in the region of Southern Ontario, we prospectively tracked all coagulation factor concentrates that were distributed from the national blood supplier, issued by hospitals for inpatient use or for home infusions, infused at hospital facilities or at home and wasted. Discrepancies were reconciled by independent audits. Trends in the utilization of FVIII, FIX and FVIIa concentrates are reported. A total of 466 patients with inherited or acquired bleeding disorders were registered. Utilization of FVIII, FIX and FVIIa increased by an average of 13.7%, 33.2% and 34.2% per year respectively. Most FVIII and FIX infusions were administered at home while most FVIIa infusions were in hospital. The increase in FVIII and FIX usage was attributable to an increase in per-patient use, predominantly for prophylaxis. In total, 1.7% of coagulation factor concentrates was wasted during the study period, at a cost of over 1 million Canadian dollars. Utilization of coagulation factor concentrates increased steadily during the study period. A regional programme to track utilization is feasible and may be used to describe trends, assist planning, and reduce costs by minimizing wastage.

Contribution of clinical breast examination to mammography screening in the early detection of breast cancer

OBJECTIVES

As the benefit of clinical breast examination (CBE) over that of screening mammography alone in reducing breast cancer mortality is uncertain, it is informative to monitor its contribution to interim measures of effectiveness of a screening programme. Here, the contribution of CBE to screening mammography in the early detection of breast cancer was evaluated.

SETTING

Four Canadian organised breast cancer screening programmes.

METHODS

Women aged 50-69 receiving dual screening (CBE and mammography) (n = 300,303) between 1996 and 1998 were followed up between screen and diagnosis. Outcomes assessed by mode of detection (CBE alone, mammography alone, or both CBE and mammography) included referral rate, positive predictive value, pathological features of tumours (size, nodal status, morphology), and cancer detection rates overall and for small cancers (< or = 10 mm or node-negative). Heterogeneity in findings across programmes was also assessed.

RESULTS

On first versus subsequent screen, CBE alone resulted in 28.5-36.7% of referrals, and 4.6-5.9% of cancers compared with 52.6-60.1% of referrals and 60.0-64.3% of cancers for mammography alone. Among cancers detected by CBE, 83.6-88.6% were also detected by mammography, whereas for mammographically detected cancers only 31.7-37.2% were also detected by CBE. On average, CBE increased the rate of detection of small invasive cancers by 2-6% over rates if mammography was the sole detection method. Without CBE, programmes would be missing three cancers for every 10,000 screens and 3-10 small invasive cancers in every 100,000 screens.

CONCLUSIONS

Inclusion of CBE in an organised programme contributes minimally to early detection.

Nitric oxide inhibition of IGF-1 stimulated proteoglycan synthesis: role of cGMP

Insulin-like growth factor (IGF-1) is critical for normal development and maintenance of cartilage, however arthritic cartilage responds poorly to IGF-1; part of this insensitivity is mediated by nitric oxide (NO). These studies test if cGMP is responsible for NO dependent insensitivity to IGF-1 in chondrocytes in situ in organ culture and in monolayer culture. Lapine cartilage and chondrocytes in monolayer culture and cartilage from osteoarthritic human knees were used. Tissues were exposed to NO from iNOS induced by IL-1, and proteoglycan synthesis in response to IGF-1 was evaluated in the presence and absence of cGMP dependent protein kinase (PKG) inhibitors. PKG activators inhibited IGF-1 responses in cartilage but not chondrocytes in monolayer. IL-1 stimulated cGMP synthesis in both monolayer and organ cultures. However, PKG inhibitors in cartilage slices but not in monolayer cultures restored response to IGF-1. PKG activity was detected in both fresh and monolayer chondrocytes, confirming this part of the cGMP signal cascade is intact in both of the preparations evaluated. Arthritic cartilage response to IGF-1 was restored by both N(G)-monomethyl-L-arginine inhibition of NO synthesis and PKG inhibitors. The data suggests that cGMP mediated effects are critical to NO actions on chondrocytes in situ in the cartilage matrix and supports a role for cGMP in the pathophysiologic effects of NO in osteoarthritis.

Insomnia related to dysthymia: polysomnographic and psychometric comparison with normal controls and acute therapeutic trials with trazodone

Utilizing polysomnography (PSG) and psychometry, objective and subjective sleep and awakening quality was investigated in 11 patients (mean age 50 +/- 14) with nonorganic insomnia (F 51.0) related to dysthymia (F 34.1) as compared with 11 age- and sex-matched normal controls. Patients demonstrated decreased sleep efficiency and sleep stage S2 as well as increased sleep latency to S1, S2 and S3, wakefulness within the total sleep period, number of awakenings, S1 and REM sleep. There was no intergroup difference in REM latency. Subjective sleep quality and the total score of the Self-Assessment Scale for Sleep and Awakening Quality (SSA) were deteriorated as were evening and morning well-being, mood, affectivity and drowsiness. Noopsychic measures showed deteriorated numerical memory, fine motor activity and reaction time variability. In a placebo-controlled crossover design study, the acute effects of 100 mg trazodone, a serotonin reuptake inhibitor with a sedative action due to 5HT(2) and alpha(1) receptor blockade, were investigated in the patients. As compared with placebo, trazodone induced an increase in slow-wave sleep (S3 + 4), a lengthening of REM latency, a decrease in REM sleep and a normalization of the periodic leg movement (PLM) index. In the morning, there was a minimal increase in somatic complaints and a decrease in critical flicker frequency and systolic blood pressure. In conclusion, our study demonstrated that dysthymia induced significant changes in objective and subjective sleep and awakening quality, which were counteracted by 100 mg trazodone, thus suggesting a key-lock principle in the treatment of nonorganic insomnia related to dysthymia with this drug.

Separation of a breast cancer cell line from human blood using a quadrupole magnetic flow sorter

We have developed a quadrupole magnetic flow sorter (QMS) to facilitate high-throughput binary cell separation. Optimized QMS operation requires the adjustment of three flow parameters based on the immunomagnetic characteristics of the target cell sample. To overcome the inefficiency of semiempirical operation/optimization of QMS flow parameters, a theoretical model of the QMS sorting process was developed. Application of this model requires measurement of the magnetophoretic mobility distribution of the cell sample by the cell tracking velocimetry (CTV) technique developed in our laboratory. In this work, the theoretical model was experimentally tested using breast carcinoma cells (HCC1954) overexpressing the HER-2/neu gene, and peripheral blood leukocytes (PBLs). The magnetophoretic mobility distribution of immunomagnetically labeled HCC1954 cells was measured using the CTV technique, and then theoretical predictions of sorting recoveries were calculated. Mean magnetophoretic mobilities of (1-3) x 10(-4) mm(3)/(T A s) were obtained depending on the labeling conditions. Labeled HCC1954 cells were mixed with unlabeled PBLs to form a "spiked" sample to be separated by the QMS. Fractional recoveries of cells for different flow parameters were examined and compared with theoretical predictions. Experimental results showed that the theoretical model accurately predicted fractional recoveries of HCC1954 cells. High-throughput (3.29 x 10(5) cells/s) separations with high recovery (0.89) of HCC1954 cells were achieved.

[Fatigue and stress sensitivity of physicians after 16 hours on duty at the emergency department]

In addition to their 40-hour working week (Mon-Fri, 8 a.m.-4 p.m.) residents at the emergency department of the General Hospital of Vienna have to do approximately six 24-hour duties. The reasons for conducting the present field study were physicians' complaints about tiring night duties. 11 residents (4 women, 7 men; aged between 28 and 43 years, x = 33.5 +/- 4.9 years; working at the emergency department for 4-50 months, x = 31 +/- 20 months) were tested on an ordinary working day at 9 a.m. and midnight. Self-rating concerning sleep duration, perception of stress and workload on the days of the investigations were found to be representative of other prolonged duties. Subjects reported a usual nocturnal sleep duration of only 6-7 hours. Stress was regarded as moderate by most of the volunteers. Blood pressure and pulse rates did not show diurnal changes. Generally, residents felt significantly (p < 0.01) less awake at night than in the morning, but reported only slight vegetative and somatic stress reactions or annoyances as assessed by the Fahrenberg self-rating scale. Interindividual differences were found; residents who had been working at the emergency department for a longer period experienced a more pronounced impairment. Further studies are required in order to objectify a nocturnal decrease in vigilance (by means of computer-assisted EEG) and to evaluate potential performance deficits (by means of psychometric tests).

Bacillus intermedius ribonuclease as inhibitor of cell proliferation and membrane current

The antiproliferative action of the guanine-specific ribonuclease secreted by Bacillus intermedius (binase) was studied in different chicken and mouse cell lines. The proliferation rate of chicken embryo fibroblasts, either normal or Rous sarcoma virus-transformed, was significantly reduced by binase treatment. Among mouse fibroblasts, v-ras-transformed NIH3T3 cells were sensitive to binase, whereas the growth of non-transformed, v-src-transformed or v-fms-transformed NIH3T3 cells was not affected. A 48 h treatment with binase inhibited the Ca2+-dependent K+ current of v-ras-transformed NIH3T3 cells but had no effect on this membrane current in non-transformed and in v-src- or v-fms-transformed NIH3T3 cells. Our results suggest that mammalian cells expressing the ras-oncogene are a potential target for the antiproliferative action of binase.

Performance of screening mammography in organized programs in Canada in 1996. The Database Management Subcommittee to the National Committee for the Canadian Breast Cancer Screening Initiative

BACKGROUND

The results of randomized trials show that breast cancer screening by mammography reduces breast cancer mortality by up to 40% in women aged 50-69 years. Because of these results, by 1998, 22 countries, including Canada, had established population-based organized screening programs. This paper presents the results of screening mammography in 1996 for 7 provincially organized breast cancer screening programs in Canada.

METHODS

Analyses of interim performance indicators for screening mammography have been calculated from data submitted to the Canadian Breast Cancer Screening database. The data set consisted of data from 7 provincial programs and was limited to mammographic screens for women aged 50-69 years (n = 203,303). Screening outcomes and performance indicators were calculated for abnormalities detected by screening mammography only.

RESULTS

The abnormal recall rate was 9.5% for first screens and 4.6% for subsequent screens, and the cancer detection rate per 1000 women screened was 6.9 for first screens and 3.8 for subsequent screens. The positive predictive value (i.e., the proportion of women who tested positive by mammography who were found to have breast cancer on screen-initiated diagnostic work-up) increased from 7.2% at the first screen to 8.2% at subsequent screens. Estimated participation rates within organized programs varied from 10.6% to 54.2%, depending on the province.

INTERPRETATION

For 1996, organized breast cancer screening programs met or exceeded many of the interim measures used in international programs. It is possible to translate the benefits of breast cancer screening by mammography, as demonstrated in randomized trials, into population-based community programs. Screening mammography through organized programs should increase to allow more comprehensive monitoring in Canada.