Trends in mammography, hormone replacement therapy, and breast cancer incidence and mortality in Canadian women.

PURPOSE: The purpose of the study is to examine relationships between long-term trends of region- and age-specific rates of mammography, hormone replacement therapy (HRT), and breast cancer incidence and mortality in Canadian women aged 35 years and older. METHODS: Population-based complex surveys were used to estimate mammography use in the past 2 years and ever, and HRT use in the past month. National population-based administrative data were used to estimate breast cancer incidence and mortality. Joinpoint analyses were used to estimate trends in rates and years where trend changed. RESULTS: No consistent relationship between mammography use and breast cancer incidence was observed across age groups. Opportunistic screening occurred prior to the establishment of organized screening programs in Canada and prior to substantial declines in breast cancer mortality observed around 1990. Women aged 35-39 years demonstrated a 62.8% relative decrease in breast cancer mortality between 1950 and 2015 despite lower rates of mammography use in the past 2 years (range 9.4-15.9%) reinforcing important treatment advances. A substantial proportion of women in their 40s report mammography use in the past 2 years (range 35.8-42.2%) and regional variation exists reflecting inconsistencies in guidelines across Canada. CONCLUSION: Rates of mammography use over time do not necessarily reflect national guideline releases or establishment of organized screening programs.

Factors associated with early extubation after superior cavopulmonary connection: analysis from single ventricle reconstruction trial.

BACKGROUND: To evaluate the landscape of early extubation, and identify factors associated with early extubation (≤ 24 h) after superior cavopulmonary connection (stage 2 operation) among children with single ventricle anatomy. METHODS: Patients undergoing stage 2 operation after Norwood operation from the Pediatric Heart Network Single Ventricle Reconstruction (SVR) trial public-use dataset were included. Elastic net regularized logistic regression models were fitted to evaluate the factors associated with early extubation after stage 2 operation. RESULTS: In total, 390 patients from 15 North American centers qualified for inclusion. Of these, 42 patients (10.8%) were extubated in operating room, 151 patients (38.7%) were extubated outside the operating room within the first 24 h after stage 2 operation, and the remaining 197 patients (50.5%) required mechanical ventilation for > 24 h. In adjusted models, factors associated with early extubation after stage 2 operation were elective timing of stage 2 operation, lower incidence of post-Norwood complications, shorter CPB duration for stage 2 operation, and no cardiac catheterization after Stage 2 operation. We also performed multiple other alternative analyses to identify factors associated with early extubation that demonstrated same associations as the primary model. The mean hospital length of stay after Stage 2 operation was 20% shorter among patients with early extubation. CONCLUSIONS: Data from this large multicenter study demonstrate that approximately one-half of the patients undergoing operation for superior cavopulmonary connection are extubated within 24 h after heart operation. Furthermore, early extubation is associated with shorter hospital length of stay.

Cardiac time intervals derived by magnetocardiography in fetuses exposed to pregnancy hypertension syndromes.

OBJECTIVE: To test the hypothesis that fetuses exposed to maternal preeclampsia or chronic hypertension have deranged development of cardiac time intervals. STUDY DESIGN: Pregnancies were divided into three groups: Intrauterine Growth Restricted (IUGR), Hypertensive, and Normal. Each group's mean fetal cardiac time intervals (P, PR, QRS and RR) derived by magnetocardiography were calculated using an analysis of covariance model's regression-adjusted estimates for a gestational age of 35 weeks. RESULTS: We reviewed 141 recordings from 21 IUGR, 46 Hypertensive and 74 Normal patients. The IUGR, Hypertensive and Normal groups, respectively, had adjusted mean intervals in milliseconds of 66.4, 66.8 and 76.2 for P (P=0.001), 95.9, 101.6 and 109.6 for PR (P=0.002), 77.2, 78.7 and 78.7 for QRS (P=0.81) and 429.8, 429.2 and 428.5 for RR (P=0.97). CONCLUSION: P and PR intervals are abbreviated in normotrophic fetuses exposed to maternal hypertension, suggesting shortened atrioventricular conduction times.

Assessing dehydroepiandrosterone in saliva: a simple radioimmunoassay for use in studies of children, adolescents and adults.

While salivary assays for some hormones are widely used, the availability of assays for salivary DHEA is limited. By adapting a commercially available radioimmunoassay serum kit, we developed a reliable, efficient and sensitive measure of DHEA in saliva that does not require separation or extraction. The minimum detection limit was 4.0 pg/ml. Intra-assay coefficients of variation (CV%) were on average 4.05, and inter-assay CVs averaged 9.70. Method accuracy, determined by spike recovery, and linearity, determined by serial dilution, averaged 99.55 and 92.03%. Levels in matched serum and saliva samples showed strong linear relationships for adult males and females. Specific guidelines are developed for sample collection, storage, and preparation procedures. Reference ranges for salivary DHEA levels are provided for 64 children ages 8-11, 96 adolescents ages 12-17 and 48 adults ages 30-45. Salivary DHEA levels are shown to reflect developmental, gender and diurnal differences.

Preferential activation of the vastus medialis oblique, vastus lateralis, and hip adductor muscles during isometric exercises in females.

Disagreement exists as to whether the individual components of the quadriceps femoris can be preferentially activated, i.e., that one muscle component is activated to a greater degree of its maximum voluntary contraction ability than the remaining components. Preferential activation of the vastus medialis (VM) might be useful in the treatment of knee patients demonstrating VM atrophy. The purpose of the present investigation was to determine if the vastus medialis oblique (VMO), vastus lateralis (VL), and hip adductor (HA) muscles were preferentially activated in females during the following maximal voluntary isometric exercises: 1) unilateral quadriceps setting (QS) with the ankle positioned in neutral, 2) unilateral quadriceps setting combined with ankle dorsiflexion (QS + D), and 3) maximal bilateral hip adduction. Integrated electromyography (IEMG in mV.sec) was determined for the VMO, VL, and HA muscles of the preferred leg (i.e., that used to kick a ball) of 20 healthy females. Data were normalized using QS exercise as the reference exercise. Nonnormalized IEMG (+/-SD) of the VMO and VL was similar during QS [i.e., VMO = 1050 (+/-802) mV.sec, VL = 1075 (+/-738) mV. sec] and QS + D exercises [i.e., VMO = 1191 (+/-738) mV.sec, VL = 1202 (+/-836) mV.sec], but significantly less than these values during hip adduction exercise [i.e., VMO = 174 (+/-62) mV. sec, VL = 194 (+/-70) mV.sec]. Nonnormalized IEMG of the HA muscles was similar during both QS and QS+D [i.e., 286 (+/-405) mV.sec and 195 (+/-432) mV.sec], but significantly higher than these values during hip adduction exercise [i.e., 413 (+/-235) mV.sec]. Normalized IEMG (+/-SD)(%) demonstrated similar patterns, i.e., the ratios for the VMO and the VL muscles did not differ from one another under either QS + D [i.e., VMO = 121 (+/-60)%, VL = 116 (+/-40)%] or hip adduction conditions [i.e., VMO = 33 (+/-24)%, VL = 36 (+/-25)%]. As a result, the degree of activation of the two muscles was considered the same. These results suggest no preferential activation of the quadriceps femoris component muscles during QS, QS + D, and hip adduction exercises in the nonweight-bearing position. The use of hip adduction to preferentially activate the VMO over the VL compared with QS exercises was not substantiated. A mean increase of 20% in the VMO and VL myoelectric activity during QS (as demonstrated by the normalized IEMG), by the addition of dorsiflexion, may be clinically significant. However, further study is required.

Reliability of non-normalized and normalized integrated EMG during maximal isometric contractions in females.

The purpose of this investigation was to examine the test-retest reliability of non-normalized (absolute or raw units of mV . s) and normalized (percentage ratio) scores using integrated electromyography (IEMG) in voluntary maximal isometric contractions. Bipolar surface electrodes on the vastus medialis (VM) and vastus lateralis (VL) muscles were used to record IEMG (mV . s) on two occasions, 2-8 days apart. While, positioned supine, 20 healthy young women (mean age 24 +/- 2 yr) performed: (a) maximal voluntary unilateral quadriceps setting (QS) (i.e. isometric knee extension with the knee in 0 degrees ) with the ankle joint in a neutral position and the ankle musculature relaxed, and (b) maximal unilateral OS with the ankle joint in maximal dorsiflexion and the ankle dorsiflexors maximally contracted (QSD). The QS exercise was used to normalize IEMG (QSD: QS ratio for each of the two muscle heads) and the VM muscle was also used to normalize IEMG to the other head of the vasti (VL: VM ratio for each exercise). Reliability coefficients were excellent for test-retest reliability of non-normalized IEMG (mV . s) and for IEMG normalized to another muscle: (intraclass correlation coefficients (ICCs) > 0.86). However, IEMG normalized to another exercise was characterized by poor reliability (ICCs < 0.34), even when determined as the reliability of data averaged over two occasions. Regardless of whether absolute or normalized IEMG was used, 95% confidence intervals were wide, suggesting that precise, interday prediction of an individual's performance using the present protocol is questionnable.