Cord-Blood Derived Chemistry Reference Values in Preterm Infants for Sodium, Chloride, Potassium, Glucose, and Creatinine

OBJECTIVE

 International guidelines recommend that preterm infants should be supported to maintain their serum electrolytes within "normal" ranges. In term babies, cord blood values differed in pathological pregnancies from healthy ones.

STUDY DESIGN

 We examined cord blood sodium, chloride, potassium, glucose, and creatinine to derive maturity-related reference intervals. We examined associations with gestational age, delivery mode, singleton versus multiple, and prenatal maternal adverse conditions. We compared preterm cord values to term, and to adult reference ranges.

RESULTS

 There were 591 infants, 537 preterm and 54 term. Preterm cord glucose levels were steady (3.7 ± 1.1 mmol/L), while sodium, chloride, and creatinine increased over GA by 0.17, 0.14 mmol/L/week, and 1.07 µmol/L/week, respectively (p < 0.003). Average preterm cord potassium and chloride were higher than the term (p < 0.05). Compared with adult reference intervals, cord preterm reference intervals were higher for chloride (100-111 vs. 98-106 mmol/L), lower for creatinine (29-84 vs. 62-115 µmol/L), and more variable for potassium (2.7-7.9 vs. 3.5-5.0 mmol/L) and sodium (130-141 vs. 136-145 mmol/L). Cesarean section was associated with higher potassium and lower glucose, multiple births with higher chloride and creatinine and lower glucose, and SGA with lower glucose.

CONCLUSION

 Cord blood values varied across the GA range with increases in sodium, chloride, and creatinine, while glucose remained steady. Average preterm reference values were higher than term values for potassium and chloride. Preterm reference values differed from published adults' reference values. The changes across GA and by delivery mode, SGA, and being a multiple, which may have direct implications for neonatal care and fluid management.

KEY POINTS

· Cord blood electrolyte, creatinine, and glucose values vary across neonatal gestational age.. · Average preterm cord values of potassium and chloride were higher than term values.. · Cord reference values differ by delivery mode, growth, and multiple impacting neonatal care decisions..

Effect of high-dose vitamin D supplementation on peripheral arterial calcification: secondary analysis of a randomized controlled trial

Although high-dose vitamin D supplementation is common, effects on arterial calcification remain unexplored. Tibial artery calcification was identified and quantified over 3 years in participants randomized to 400, 4000, or 10,000 IU vitamin D₃ daily. High-dose vitamin D supplementation did not affect the development or progression of arterial calcification.

INTRODUCTION

To determine whether vitamin D supplementation has a dose-dependent effect on development and progression of arterial calcification.

METHODS

This was a secondary analysis of the Calgary Vitamin D Study, a 3-year, double-blind, randomized controlled trial conducted at a single-center in Calgary, Canada. Participants were community-dwelling adults aged 55-70 years with serum 25-hydroxyvitamin D 30-125 nmol/L. Participants were randomized 1:1:1 to receive vitamin D₃ 400, 4000, or 10,000 IU/day for 3 years. Tibial artery calcification was identified and quantified (in milligrams of hydroxyapatite, mgHA) using high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline and 6, 12, 24, and 36 months. Changes in calcification over time and treatment group interaction were evaluated using a constrained linear mixed effects model.

RESULTS

Of 311 randomized participants, 302 (400: 105, 4000: 96, 10,000: 101) were eligible for analysis of arterial calcification (54% male, mean (SD) age 62 (4) years, mean (SD) 25-hydroxyvitamin D 78.9 (19.9) nmol/L). At baseline, 85 (28%) had tibial artery calcification, and mean (95% CI) calcification quantity was 2.8 mgHA (95% CI 1.7-3.9). In these 85 participants, calcification quantity increased linearly by 0.020 mgHA/month (95% CI 0.012-0.029) throughout the study, with no evidence of a treatment-group effect (p = 0.645 for interaction). No participants developed new arterial calcifications during the study.

CONCLUSIONS

In this population of community-dwelling adults who were vitamin D replete at baseline, supplementation with vitamin D 400, 4000, or 10,000 IU/day did not have differential effects on the development or progression of arterial calcification over 3 years.

TRIAL REGISTRATION

clinicaltrials.gov (NCT01900860).

Genetic Association Study in Multigenerational Kindreds With Vasovagal Syncope: Evidence for Involvement of Sex-Specific Serotonin Signaling

BACKGROUND

Several studies suggest that vasovagal syncope has a genetic origin, but this is unclear. We assessed whether plausible gene variants associate with vasovagal syncope.

METHODS

We studied 160 subjects in 9 kindreds comprising 82 fainters and 78 controls. The diagnosis was ascertained with the Calgary Syncope Score. Common genetic variants were genotyped for 12 genes for vascular signaling, potassium channels, the HTR1A(serotonin 5-HT1A receptor), SLC6A4(serotonin reuptake transporter), and COMT(catecholamine O-methyltransferase). Sex-specific associations between genotypes and phenotypes were tested.

RESULTS

In 9 out of 12 variants, there was no significant association between genotype and phenotype. However, the HTR1A(-1019) G alleles associated with syncope in males, but not in females ( P=0.005). CC and GG males had 9% versus 77% likelihoods of syncope. The SLC6A4 promoter L alleles associated with decreased syncope in males but increased in females ( P=0.059). The LL and SS males had 25% and 47% syncope likelihoods, whereas females had 75% and 50% syncope likelihoods. The COMT c.472 A alleles associated with decreased syncope in males but increased in females ( P=0.017). The GG and AA males had 50% and 15% syncope likelihoods, whereas females had 52% and 73% syncope likelihoods.

CONCLUSIONS

There is a sex-dependent effect of alleles of serotonin signaling and vasovagal syncope, supporting the serotonin hypothesis of the physiology of vasovagal syncope.

Long-Term Follow-up and Quantitative Hepatitis B Surface Antigen Monitoring in North American Chronic HBV Carriers

INTRODUCTION

Quantitative hepatitis B surface antigen (qHBsAg) combined with HBV DNA may be useful for predicting chronic hepatitis B (CHB) activity and nucleoside analogue (NA) response.

MATERIAL AND METHODS

In this retrospective cohort study we evaluated qHBsAg levels according to CHB disease phase and among patients on treatment. Random effect logistic regression analysis was used to analyze qHBsAg change with time in the NA-treated cohort.

RESULTS

545 CHB carriers [56% M, median age 48 y (IQR 38-59), 73% Asian] had qHBsAg testing. In the untreated group (44%), 8% were classified as immune tolerant, 10% immune clearance, 40% inactive, and 43% had HBeAg- CHB and the median HBsAg levels were 4.6 (IQR 3.4-4.9), 4.0 (IQR 3.4-4.5), 2.9 (IQR 1.4-3.8), and 3.2 log IU/mL (IQR 2.6-4.0), respectively; p < 0.001. In the NA-treated group (28% entecavir, 68% tenofovir, 4% lamivudine), no significant change in qHBsAg levels occured with time. However, 19% of patients on long-term NA had sustained qHBsAg < 2 log10 IU/mL.

CONCLUSION

qHBsAg titers were associated with CHB phase and remained stable in those on long-term NA. A significant number of treated patients had low-level qHBsAg, of which some may be eligible for treatment discontinuation without risk of flare.

Risk and Protective Factors for Late Talking: An Epidemiologic Investigation

OBJECTIVE

To identify risk and protective factors for late talking in toddlers between 24 and 30 months of age in a large community-based cohort.

STUDY DESIGN

A prospective, longitudinal pregnancy cohort of 1023 mother-infant pairs in metropolitan Calgary, Canada, were followed across 5 time points: before 25 weeks gestation, between 34-36 weeks gestation, and at 4, 12, and 24 months postpartum. Toddlers who scored ≤10th percentile on The MacArthur-Bates Communicative Development Inventories: Words and Sentences between 24 and 30 months of age were identified as late talkers. Thirty-four candidate characteristics theoretically and/or empirically linked to language development and/or language impairment were collected using survey methodology.

RESULTS

The prevalence of late talking was 12.6%. Risk factors for late talking in the multivariable model included: male sex (P = .017) and a family history of late talking and/or diagnosed speech or language delay (P = .002). Toddlers were significantly less likely to be late talkers if they engaged in informal play opportunities (P = .013), were read to or shown picture books daily (P < .001), or cared for primarily in child care centers (P = .001).

CONCLUSIONS

Both biological and environmental factors were associated with the development of late talking. Biological factors placed toddlers at risk for late talking, and facets of the environment played a protective role. Enveloping infants and toddlers in language-rich milieus that promote opportunities for playing, reading, and sharing books daily may decrease risk for delayed early vocabulary.

End-of-life cancer care: Health service delivery in the last 12 months of life in Calgary, Alberta, Canada

171

Background: In Calgary, Alberta, the Calgary Zone Palliative Care Collaborative (CZPCC) undertook a study to examine the current state of cancer and palliative services and to recommend steps to address gaps in service delivery. We hypothesized that early access to palliative care services would reduce utilization of active cancer treatments and services for individuals nearing the end of life. Our study objectives were to determine the utilization and timing of acute, palliative and oncology-related services in Calgary. Methods: This retrospective study examined cancer registry and administrative data for patients > 18 years, who died in 2012. Measures of aggressive end of life care (EOL) were also collected. A combination of descriptive statistics, tests of association and multivariate regression analysis were conducted. Results: N = 1909 died of cancer in 2012: median age 73 years (IQR: 62-82 years) and median disease duration 364 days (IQR: 92-1114 days). 40.6% of patients received systemic treatment in last 12 months of life. 29.9% received radiotherapy and 13.0% received psychosocial/spiritual care. Palliative care contact was 80.7%, inclusive of 20.6% who had an intensive palliative care unit admission. 5.2% had EOL chemotherapy and 3.8% received EOL radiotherapy. Up to 10.4% of patients had one or more hospital admission. There was no significant effect of age on those who received aggressive EOL care. Men had an increased probability to receive aggressive EOL care (p = 0.015). Tumor group was also associated with receiving aggressive EOL (p < 0.001), with the highest utilization in Head and Neck and hematological malignancies. In patients with a disease duration of > 4 months those who received palliative care at least 2-3 months prior to death were less likely to receive aggressive EOL care (P < 0.001). Patients whose disease duration was < 1 month were less likely to receive aggressive EOL care if they received palliative care services (p = 0.02). Conclusions: The provision of palliative care services at the end of life is most needed among men and certain tumor groups who are the highest users of aggressive EOL care.

Predictors of referral for neoadjuvant chemotherapy prior to radical cystectomy for muscle-invasive bladder cancer and changes in practice over time

INTRODUCTION

In patients with non-metastatic muscle-invasive bladder cancer (MIBC) fit for curative therapy, a multidisciplinary approach consisting is recommended. This approach includes local treatment (usually radical cystectomy), ideally combined with neoadjuvant chemotherapy (NACT). Despite a survival benefit with NACT, uptake remains low. We assessed NACT consultation in Alberta and examined associative factors, as well as the relationship to survival.

METHODS

Patients with MIBC were identified through the Alberta Cancer Registry. Demographic and clinicopathologic information was collected from electronic medical records between 2007 and 2011. In addition to descriptive statistics, logistic regression was used to determine factors associated with receiving NACT consultation. Overall survival was described using a Kaplan-Meier estimate.

RESULTS

Of the 315 radical cystectomy patients, 140 (45.1%, 95% confidence interval [CI] 39.5, 50.8) received NACT consultation. Patients ≥80 years (odds ratio [OR] 0.21, 95% CI 0.08, 0.57, p = 0.002) and those treated in Calgary (OR 0.11, 95% CI 0.05, 0.25, p < 0.001) were less likely to receive NACT consultation. The rate of NACT consultation increased steadily from 2007 to 2011 (OR 1.23, 95% CI 1.04, 1.45 per year of diagnosis, p = 0.018). After a median follow-up of 28.1 months (range: 14.6-50.3), median survival was 54.7 months for patients who received NACT consultation versus 31.2 months for those who did not (p = 0.030).

CONCLUSIONS

NACT consultation in patients with MIBC undergoing radical cystectomy has improved over time; however, regional differences underscore the need for a standardized approach to NACT consultation, including common referral mechanisms.

ATM, THMS, and RRM1 protein expression in nasopharyngeal carcinomas treated with curative intent

BACKGROUND

In advanced nasopharyngeal carcinoma (NPC), biomarkers may help predict survival.

METHODS

Tumoral expression of ataxia-telangiectasia mutated (ATM), thymidylate synthetase (THMS), and ribonucleotide reductase subunit M1 (RRM1), was correlated with survival in patients with nonmetastatic NPC using quantitative fluorescence immunohistochemistry with automated quantitative digital image analysis.

RESULTS

Of the 146 patients included, 58 patients (40%) received concurrent chemoradiation therapy; the remainder was treated with radiation. Overall survival (OS) at 5 years was 71% (95% confidence interval [CI], 62% to 78%); disease-free survival (DFS) was 48% (95% CI, 39% to 57%). OS worsened for increasing values of ATM (hazard ratio [HR], 2.83; 95% CI, 1.01-7.94; p = .049) for values greater than the 75th percentile compared to less than the 25th percentile, but improved for tumors with higher THMS levels (HR, 0.44; 95% CI, 0.20-0.94; p = .033) for values greater than the 25th percentile compared to less than or equal to the 25th percentile. RRM1 was not associated with OS (p = .748). No biomarkers were associated with DFS.

CONCLUSION

In our cohort, relative overexpression of ATM and low THMS levels were associated with worse OS. © 2015 Wiley Periodicals, Inc. Head Neck 38: E384-E391, 2016.

Hemodynamic Stability During Pheochromocytoma Resection: Lessons Learned Over the Last Two Decades

BACKGROUND

Ideal perioperative management of pheochromocytomas/paragangliomas (pheo) is a subject of debate and can be highly variable. The purpose of this study was to identify potential predictive factors of hemodynamic instability during pheo resection.

METHODS

A retrospective review of pheo resections from 1992 to 2013 was undertaken. Intraoperative hemodynamics, patient demographics, tumor characteristics, and perioperative management were examined. Postoperative intensive-care admission, myocardial infarction, stroke, and 30-day mortality were reviewed. Linear regression was used to analyze factors influencing intraoperative hemodynamics.

RESULTS

During the 20-year study period, 100 patients underwent pheo resection. Postoperative morbidity and mortality was significantly reduced (p = 0.003) in the last 10 years of practice, and there was a trend towards greater morbidity and mortality with intraoperative hemodynamic instability (p = 0.06). The preoperative dose of phenoxybenzamine and the number of laparoscopic procedures has increased in the last decade [59 mg (95 % CI 32-108) to 106 mg (95 % CI 91-124), p = 0.008, and 27 vs. 54 %, p = 0.05, respectively]. Increased preoperative phenoxybenzamine dose was a significant predictor of improved intraoperative hemodynamic stability (p = 0.01). Lack of intraoperative magnesium use resulted in greater hemodynamic instability as preoperative systolic blood pressure increased (p = 0.002).

CONCLUSIONS

Postoperative outcomes following pheo resection have improved over the last two decades. Preoperative α-blockade plays a significant role in improving intraoperative hemodynamics and post-op outcomes. Increased doses of phenoxybenzamine and utilization of laparoscopic approaches have likely contributed to improved outcomes in the last decade. Intraoperative magnesium use may provide protection against hemodynamic instability and warrants further study.

Evaluation of E-cadherin, β-catenin and vimentin protein expression using quantitative immunohistochemistry in nasopharyngeal carcinoma patients

PURPOSE

Aberrant expression of proteins involved in epithelial-to-mesenchymal transition have been described in various cancers. In this retrospective study, we sought to evaluate E-cadherin, β-catenin and vimentin protein expression in non-metastatic nasopharyngeal (NPC) patients treated with curative intent, examine their relationship with each other, and with clinical outcome measures.

METHODS

Pre-treatment formalin-fixed paraffin-embedded biopsies of 140 patients treated between January 2000 and December 2007 were assembled into a tissue microarray (TMA). Automated quantitative immunohistochemistry (AQUA®) was performed on sequential TMA sections stained with fluorescent-labeled antibodies against E-cadherin, β-catenin and vimentin. Cox proportional hazards regression was used to estimate the effect of cytoplasmic vimentin, cytoplasmic E-cadherin, β-catenin nuclear/cytoplasmic ratio expression on overall survival and disease-free survival.

RESULTS

The average age of the patients was 51.7 years (SD=12.1; range 18-85), 66% were male, 71% had a KPS ≥ 90% at the start of treatment and 65% had stage III/IV disease. After adjusting for performance status, WHO and stage, high E-cadherin levels over the 75th percentile were found to produce a significantly increased risk for both a worse overall survival (HR = 2.53, 95% CI 1.21, 5.27) and disease free survival (DFS; HR = 2.14, 95%CI 1.28, 3.59). Vimentin levels over the first quartile produced an increased risk for a worse DFS (HR = 2.21, 95% CI 1.11, 4.38). No association was seen between β-catenin and survival.

CONCLUSION

In this cohort of NPC patients, higher levels of E-cadherin and higher levels of vimentin were associated with worse outcomes. Further work is needed to understand the role of these epithelial mesenchymal transition proteins in NPC.

An examination of the effectiveness of Handwriting Without Tears® instruction

Background.

Handwriting is an important childhood occupation, and implications of poor handwriting may have significant long-term effects.

Purpose.

The purpose of this study was to determine the effectiveness of Handwriting Without Tears® (HWT) on Grade 1 students’ handwriting and perception of skills.

Methods.

A cross-over design was used. Repeated measures, at three points, included the Minnesota Handwriting Assessment (MHA) and performance rating scales.

Findings.

Eighty-three boys and 66 girls with an average age of 6.2 years participated in the study. Students receiving HWT achieved significantly higher improvements compared to students with teacher-designed instruction in MHA Total Test Score and in MHA components of form, size, space, and alignment (all p < .05). Students had higher average performance ratings when receiving HWT in the first half of the school year.

Implications.

Instruction using HWT improves students’ perception and skill in handwriting performance.

Inter-rater reliability of the Active Straight-Leg Raise and One-Leg Standing tests in non-pregnant women

OBJECTIVE

To determine the inter-rater reliability of the Active Straight-Leg Raise and One-Leg Standing tests.

DESIGN

Cross-sectional pilot study.

SUBJECTS

Thirty-one women who were either not pregnant or at least 9 months post-partum.

METHODS

Subjects completed a questionnaire and standardized pain and disability assessments. The Active Straight-Leg Raise and One-Leg Standing tests were assessed by 3 independent, blinded examiners. Inter-rater reliability was determined, and relationships with assessments were explored.

RESULTS

For the Active Straight-Leg Raise test, the kappa coefficient was 0.87, sensitivity 71%, and specificity 91%. Relationships with various pain and disability assessments were demonstrated, including the Functional Pelvic Pain Scale (r = 0.77) and Roland-Morris Disability Questionnaire (r = 0.70). For the One-Leg Standing test, kappa coefficients were -0.02 and 0.14 for the left and right sides, respectively, and thus no further analyses were performed.

CONCLUSION

In women with a spectrum of low-back and pelvic pain, the Active Straight-Leg Raise test had good inter-rater reliability, whereas the One-Leg Standing test did not. Further studies are required regarding the validity of the Active Straight-Leg Raise test.

Social equity in Human Papillomavirus vaccination: a natural experiment in Calgary Canada

BACKGROUND

The Alberta Immunization Program offers a vaccine against the Human Papillomavirus (HPV) free of charge to all girls in Grades 5 and 9. The vaccine is provided in two different service delivery models depending upon the acceptance of the program by the local school board. Vaccinations may be provided "in-school" or in "community" through appointments at Public Health Clinics. The purpose of this study was to determine whether there was a difference in vaccine uptake in Calgary between the two service delivery models, "in-school" and "community", and to examine if socioeconomic status (SES) was a contributing factor.

METHODS

Individual data from the Calgary Zone Public Health vaccination database for all grade 5 and 9 girls in Calgary for school years 2008-2011 were analyzed using descriptive statistics. These data included vaccination records for 35,592 girls. Logistic regression was used to examine the effect of delivery system and SES status on being vaccinated, controlling for school type.

RESULTS

HPV vaccination completion rates were 75% (95% confidence interval = 74.7%, 75.8%) for girls with an "in-school" compared to 36% (95% confidence interval = 35.3%, 37.2%) for girls in schools with a "community" service delivery model. A girl's neighbourhood SES was related to the likelihood of being HPV vaccinated depending on the service delivery model available to her. For girls attending a Public school with an "in-school" delivery model, the proportion completing vaccination increased as SES decreased (high SES = 79%; medium SES = 79%; low SES = 83%; p-value<0.001). For girls attending Calgary Catholic School District schools with the "community" delivery model there was a decrease in immunization rates from high and mid to low SES (high SES = 41%; medium SES = 42%; low SES = 34%; p-value<0.001). These results show that those with lower SES were differentially disadvantaged by not having access to an "in-school" vaccination delivery model.

CONCLUSION

Service delivery models make a difference in HPV vaccination completion rates and create inequities for health protection and disease prevention based on socioeconomic status.

Abstract 3545: ATM, TS and RRM1 protein expression in nasopharyngeal carcinomas (NPC) treated with curative intent

Background: Although NPC is a radiation and chemotherapy sensitive tumour, some patients still relapse with distant metastatic disease. Biomarkers are needed to help identify which patients are at higher risk of relapse and/or who will respond to therapy. Ataxia telangiectasia mutated (ATM) is a putative marker for radiation sensitivity while, thymidylate synthetase (TS), and ribonucleotide reductase subunit M1 (RRM1) levels have been associated with response to 5FU and gemcitabine, two chemotherapy agents often used in NPC. We characterized the protein expression of ATM, TS, and RRM1 in tumours from 146 patients with non-metastatic NPC treated at two Canadian institutions between Jan 2000-Dec 2007 and explored the relationship of each marker with clinical outcomes. Methods: Pre-treatment, formalin-fixed, paraffin-embedded NPC tumour specimens were assembled in a tissue microarray. ATM, TS and RRM1 protein expression were evaluated by quantitative fluorescence immunohistochemistry and with automated quantitative digital image analysis (AQUA) using the Y170, TS106 and 60073-2-Ig monoclonal antibodies respectively. Protein expression levels were assessed in tumour, tumour cytoplasm, tumour nuclear, and non-malignant tumour stroma compartments. The effect of protein expression levels on overall survival (OS) and disease-free survival (DFS) was examined using Cox regression. For all biomarkers, AQUA scores were analyzed in quartiles. Results: Patient characteristics were: mean age=52 years (SD=12.2; range 18 to 85), 67% male, 73% KPS ≥ 90%, WHO type 1/2/3=11%/28%/61%, stage III/IV=65%. Fifty-eight (40%) patients received platinum-based CRT; the remainder was treated with RT alone. With a median follow-up of 50 months (range 3 to 120), the 5 year survival rates were 71% (95% CI=62%-78%) for OS and 48% (95% CI=39%-57%) for DFS. After adjusting for KPS, stage, and WHO type, OS was worse for the group with tumour:stromal (T/S) ATM ratios in the top quartile versus those in the lowest quartile (p=0.049). OS was also worse for tumours with TS levels in the lowest quartile versus the top quartile (p=0.033). RRM1 was not associated with outcomes (p=0.748). There was no significant effect of any of the biomarkers on disease-free survival (ATM T/S p=0.708; TS p=0.978; RRM1 p=0.918). Conclusions: In our cohort of non-metastatic NPC patients, relative overexpression of ATM and low TS protein levels were associated with worse outcomes suggesting further investigation of these potential biomarkers is warranted.

Citation Format: Alexander C. Klimowicz, Amanda Jagdis, Tien Phan, Janessa J. Laskin, Harold Y. Lau, Jodi E. Siever, Stephanie K. Petrillo, Thomas A. Thomson, M. Sarah Rose, Anthony M. Magliocco, Desirée Hao. ATM, TS and RRM1 protein expression in nasopharyngeal carcinomas (NPC) treated with curative intent. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3545. doi:10.1158/1538-7445.AM2013-3545

Hospital re-admission of late preterm or term infants is not a factor influencing duration of predominant breastfeeding

OBJECTIVE

To determine whether hospital re-admission within the first 2 months of life decreases the odds of predominant breastfeeding.

DESIGN

Mothers living in two large healthcare regions of Alberta (population 1 000 000 each) were recruited to participate in this prospective matched cohort study if they delivered a singleton infant between 34 and 41 weeks' gestation and were discharged within 7 days. Re-admitted infants were matched to non-re-admitted infants by site and date of birth. Questionnaires were mailed at 2 months postpartum. Predominant breastfeeding was defined as breastfeeding for at least three feedings per day for the past 7 days.

RESULTS

A total of 1798 mothers were eligible for analysis, (n=250 re-admitted, 1548 non-re-admitted). Seventy three per cent (n=1315) reported predominant breastfeeding at 2 months. Infant re-admission (adjusted OR: 1.12, 95% CI 0.8 to 1.55) and late preterm birth were not associated with discontinuation of predominant breastfeeding. The odds of predominantly breastfeeding were two times greater, if mothers' perceptions of talking about breastfeeding with a healthcare provider were positive versus negative. Whereas the odds were decreased for primiparous women (adjusted OR 0.61 95% CI 0.47 to 0.78) and not impacted for multiparous women (OR 0.60 95% CI 0.32 to 1.13) with a negative versus neutral perception of the breastfeeding talk experience.

CONCLUSIONS

Hospital re-admission and late preterm birth had no significant impact on the odds of predominant breastfeeding beyond 8 weeks post partum whereas the odds were increased with a perception of a positive experience in speaking with a healthcare provider.

Recent history of vasovagal syncope in a young, referral-based population is a stronger predictor of recurrent syncope than lifetime syncope burden

INTRODUCTION

accurate selection of patients for vasovagal syncope studies requires strong risk stratification and knowledge of the natural history of syncope. We aimed to test the hypothesis that recent history of vasovagal syncope compared to distant history better predicts subsequent recurrence of syncope.

METHODS AND RESULTS

in all, 208 subjects with a positive tilt test and ≥ 3 lifetime syncope spells were followed for 1 year. Syncope episodes in the preceding year and total historical spells were compared for their ability to predict a syncope recurrence using the criteria of optimal statistical significance, best linear separation of risk populations, and impact on power calculations. The number of vasovagal syncope spells in the preceding year better predicted syncope recurrence when compared to total number of historical spells (likelihood ratio statistic 28.4, P < 0.0001; versus 20.4, P = 0.001), and showed a substantial effect as the number of syncope events increased. For example, syncope recurred in 22% of those with <2 spells in the previous year compared to 69% in those with >6 spells. A history of no syncope compared to any syncope in the preceding year was associated with a 1-year probability of 7% versus 46% for syncope recurrence. A study designed to detect a 50% decrease in syncope recurrence at P = 0.05 with 80% power would require 159 patients with at least 3 lifetime spells, and only 108 patients with at least 3 spells in the previous year.

CONCLUSIONS

the number of syncope events in the year preceding clinical evaluation is the best predictor of syncope recurrence.

Cord blood calcium, phosphate, magnesium, and alkaline phosphatase gestational age-specific reference intervals for preterm infants

Background

The objective was to determine the influence of gestational age, maternal, and neonatal variables on reference intervals for cord blood bone minerals (calcium, phosphate, magnesium) and related laboratory tests (alkaline phosphatase, and albumin-adjusted calcium), and to develop gestational age specific reference intervals based on infants without influential pathological conditions.

Methods

Cross-sectional study. 702 babies were identified as candidates for this study in a regional referral neonatal unit. After exclusions (for anomalies, asphyxia, maternal magnesium sulfate administration, and death), relationships were examined between cord blood serum laboratory analytes (calcium, phosphate, magnesium, alkaline phosphatase, and albumin-adjusted calcium) with gestation age and also with maternal and neonatal variables using multiple linear regression. Infants with influential pathological conditions were omitted from the development of gestational age specific reference intervals for the following categories: 23-27, 28-31, 32-34, 35-36 and > 36 weeks.

Results

Among the 506 preterm and 54 terms infants included in the sample. Phosphate, magnesium, and alkaline phosphatase in cord blood serum decreased with gestational age, calcium increased with gestational age. Those who were triplets, small for gestational age, and those whose mother had pregnancy-induced hypertension were influential for most of the analytes. The reference ranges for the preterm infants ≥ 36 weeks were: phosphate 1.5 to 2.6 mmol/L (4.5 to 8.0 mg/dL), calcium: 2.1 to 3.1 mmol/L (8.3 to 12.4 mg/dL); albumin-adjusted calcium: 2.3 to 3.2 mmol/L (9.1 to 12.9 mg/dL); magnesium 0.6 to 1.0 mmol/L (1.4 to 2.3 mg/dL), and alkaline phosphatase 60 to 301 units/L.

Conclusions

These data suggest that gestational age, as well as potentially pathogenic maternal and neonatal variables should be considered in the development of reference intervals for preterm infants.

Declining conventional cancer treatment and using complementary and alternative medicine: a problem or a challenge?

Background

Several studies have shown that a small but significant percentage of cancer patients decline one or more conventional cancer treatments and use complementary and alternative medicine (cam) instead.

Objectives

Here, drawing on the literature and on our own ongoing research, we describe why cancer patients decide to decline conventional cancer treatments, who those patients are, and the response by physicians to patients who make such decisions.

Results

Poor doctor–patient communication, the emotional impact of the cancer diagnosis, perceived severity of conventional treatment side effects, a high need for decision-making control, and strong beliefs in holistic healing appear to affect the decision by patients to decline some or all conventional cancer treatments. Many patients indicate that they value ongoing follow-up care from their oncologists provided that the oncologists respect their beliefs. Patients declining conventional treatments have a strong sense of internal control and prefer to make the final treatment decisions after considering the opinions of their doctors. Few studies have looked at the response by physicians to patients making such a decision. Where research has been done, it found that a tendency by doctors to dichotomize patient decisions as rational or irrational may interfere with the ability of the doctors to respond with sensitivity and understanding.

Conclusions

Declining conventional treatment is not necessarily an indicator of distrust of the medical system, but rather a reflection of many personal factors. Accepting and respecting such decisions may be instrumental in “keeping the door open.”

Microvascular function predicts cardiovascular events in primary prevention: long-term results from the Firefighters and Their Endothelium (FATE) study

BACKGROUND

Biomarkers of atherosclerosis may refine clinical decision making in individuals at risk of cardiovascular disease. The purpose of the study was to determine the prognostic significance of endothelial function and other vascular markers in apparently healthy men.

METHODS AND RESULTS

The cohort consisted of 1574 men (age, 49.4 years) free of vascular disease. Measurements included flow-mediated dilation and its microvascular stimulus, hyperemic velocity, carotid intima-media thickness, and C-reactive protein. Cox proportional hazard models evaluated the relationship between vascular markers, Framingham risk score, and time to a first composite cardiovascular end point of vascular death, revascularization, myocardial infarction, angina, and stroke. Subjects had low median Framingham risk score (7.9%). Cardiovascular events occurred in 71 subjects (111 events) over a mean follow-up of 7.2±1.7 years. Flow-mediated dilation was not associated with subsequent cardiovascular events (hazard ratio, 0.92; P=0.54). Both hyperemic velocity (hazard ratio, 0.70; 95% confidence interval, 0.54 to 0.90; P=0.006) and carotid intima-media thickness (hazard ratio, 1.45; confidence interval, 1.15 to 1.83; P=0.002) but not C-reactive protein (P=0.35) were related to events in a multivariable analysis that included Framingham risk score (per unit SD). Furthermore, the addition of hyperemic velocity to Framingham risk score resulted in a net clinical reclassification improvement of 28.7% (P<0.001) after 5 years of follow-up in the intermediate-risk group. Overall net reclassification improvement for hyperemic velocity was 6.9% (P=0.24).

CONCLUSIONS

In men, hyperemic velocity, the stimulus for flow-mediated dilation, but not flow-mediated dilation itself was a significant risk marker for adverse cardiovascular outcomes. The prognostic value was additive to traditional risk factors and carotid intima-media thickness. Hyperemic velocity, a newly described marker of microvascular function, is a novel tool that may improve risk stratification of lower-risk healthy men.

Validation of a New Simple Scale to Measure Symptoms in Atrial Fibrillation

Background— Atrial fibrillation (AF) is commonly associated with impaired quality of life. There is no simple validated scale to quantify the functional illness burden of AF. The Canadian Cardiovascular Society Severity in Atrial Fibrillation (CCS-SAF) scale is a bedside scale that ranges from class 0 to 4, from no effect on functional quality of life to a severe effect on life quality. This study was performed to validate the scale.

Methods and Results— In 484 patients with documented AF (62.2�12.5 years of age, 67% men; 62% paroxysmal and 38% persistent/permanent), the SAF class was assessed and 2 validated quality-of-life questionnaires were administered: the SF-36 generic scale and the disease-specific AFSS (University of Toronto Atrial Fibrillation Severity Scale). There is a significant linear graded correlation between the SAF class and measures of symptom severity, physical and emotional components of quality of life, general well-being, and health care consumption related to AF. Patients with SAF class 0 had age- and sex-standardized SF-36 scores of 0.15�0.16 and −0.04�0.31 (SD units), that is, units away from the mean population score for the mental and physical summary scores, respectively. For each unit increase in SAF class, there is a 0.36 and 0.40 SD unit decrease in the SF-36 score for the physical and mental components. As the SAF class increases from 0 to 4, the symptom severity score (range, 0 to 35) increases from 4.2�5.0 to 18.4�7.8 ( P <0.0001).

Conclusions— The CCS-SAF scale is a simple semiquantitative scale that closely approximates patient-reported subjective measures of quality of life in AF and may be practical for clinical use.

A prevention strategy to reduce the incidence of injury in high school basketball: a cluster randomized controlled trial

OBJECTIVE

To examine the effectiveness of a sport-specific balance training program in reducing injury in adolescent basketball.

DESIGN

Cluster randomized controlled trial.

SETTING

Twenty-five high schools in Calgary and surrounding area.

SUBJECTS

Nine hundred and twenty high school basketball players (ages 12-18).

INTERVENTION

Subjects were randomly allocated by school to the control (n = 426) and training group (n = 494). Both groups were taught a standardized warm-up program. The training group was also taught an additional warm-up component and a home-based balance training program using a wobble board.

MAIN OUTCOME MEASURES

All injuries occurring during basketball that required medical attention and/or caused a player to be removed from that current session and/or miss a subsequent session were then recorded and assessed by a team therapist who was blinded to training group allocation.

RESULTS

A basketball-specific balance training program was protective of acute-onset injuries in high school basketball [RR = 0.71 (95% CI; 0.5-0.99)]. The protective effect found with respect to all injury [RR = 0.8 (95% CI; 0.57-1.11)], lower-extremity injury [RR = 0.83 (95% CI; 0.57-1.19)], and ankle sprain injury [RR = 0.71 (95% CI; 0.45-1.13)] were not statistically significant. Self-reported compliance to the intended home-based training program was poor (298/494 or 60.3%).

CONCLUSIONS

A basketball-specific balance training program was effective in reducing acute-onset injuries in high school basketball. There was also a clinically relevant trend found with respect to the reduction of all, lower-extremity, and ankle sprain injury. Future research should include further development of neuromuscular prevention strategies in addition to further evaluation of methods to increase compliance to an injury-prevention training program in adolescents.

Long-term effectiveness of extracorporeal shockwave therapy in the treatment of previously untreated lateral epicondylitis

OBJECTIVE

To describe the outcomes of a cohort of individuals involved in a randomized control trial of extracorporeal shockwave therapy (ESWT) in the treatment of lateral epicondylitis (LE) not previously treated.

DESIGN

Prospective cohort.

SETTING

General population.

PATIENTS

Sixty subjects (23 female, 37 male) who participated in a double-blind randomized control trial on the effectiveness of ESWT in the treatment of LE. All subjects had previously not received therapy for their LE.

INTERVENTION

At the 8-week follow-up of a randomized control trial comparing ESWT with a stretching protocol for treatment of LE, all subjects were unblinded to their treatment allocation, and subjects initially allocated to sham therapy were offered active therapy.

MAIN OUTCOME MEASURES

Overall elbow pain (10-cm visual analogue scale [VAS]) and maximum pain-free grip strength were evaluated at 0, 4, and 8 weeks and 3, 6, and 9 to 12 months postinitiation of therapy. Time to pain-free status (less than 1 cm on the VAS) was calculated from time of onset of symptoms, time of inclusion into the trial, and time from initiation of active therapy.

MAIN RESULTS

A statistically significant difference in time to pain-free status was not detected between groups. Duration of symptoms was identified to be an effect modifier of early response to therapy (at least 50% improvement on the VAS at 8-week postinitiation of therapy). A higher proportion of subjects treated within 16 weeks of onset of LE symptoms showed a response to ESWT than subjects treated after 16 weeks of onset of their LE symptoms.

CONCLUSIONS

The use of ESWT with a stretching program is not supported by this study, with the possible exception of the possible interaction effect of time of ESWT initiation from the time of onset of symptoms, which requires further investigation.

Muon spin relaxation and isotropic pairing in superconducting PrOs4Sb12

Transverse-field muon-spin rotation measurements in the vortex-lattice of the heavy-fermion (HF) superconductor PrOs4Sb12 yield a temperature dependence of the magnetic penetration depth lambda indicative of an isotropic or nearly isotropic energy gap. This is not seen to date in any other HF superconductor and is a signature of isotropic pairing symmetry, possibly related to a novel nonmagnetic "quadrupolar Kondo" HF mechanism in PrOs4Sb12. The T=0 relaxation rate sigma(s)(0)=0.91(1) micros(-1) yields an estimated magnetic penetration depth lambda(0)=3440(20) A, which is considerably shorter than in other HF superconductors.

The impact of face shield use on concussions in ice hockey: a multivariate analysis

OBJECTIVE

To identify specific risk factors for concussion severity among ice hockey players wearing full face shields compared with half face shields (visors).

METHODS

A prospective cohort study was conducted during one varsity hockey season (1997-1998) with 642 male ice hockey players (median age 22 years) from 22 teams participating in the Canadian Inter-University Athletics Union. Half of the teams wore full face shields, and half wore half shields (visors) for every practice and game throughout the season. Team therapists and doctors recorded on structured forms daily injury, participation, and information on face shield use for each athlete. The main outcome measure was any traumatic brain injury requiring assessment or treatment by a team therapist or doctor, categorised by time lost from subsequent participation and compared by type of face shield worn.

RESULTS

Players who wore half face shields missed significantly more practices and games per concussion (2.4 times) than players who wore full face shields (4.07 sessions (95% confidence interval (CI) 3.48 to 4.74) v 1.71 sessions (95% CI 1.32 to 2.18) respectively). Significantly more playing time was lost by players wearing half shields during practices and games, and did not depend on whether the athletes were forwards or defence, rookies or veterans, or whether the concussions were new or recurrent. In addition, players who wore half face shields and no mouthguards at the time of concussion missed significantly more playing time (5.57 sessions per concussion; 95% CI 4.40 to 6.95) than players who wore half shields and mouthguards (2.76 sessions per concussion; 95% CI 2.14 to 3.55). Players who wore full face shields and mouthguards at the time of concussion lost no playing time compared with 1.80 sessions lost per concussion (95% CI 1.38 to 2.34) for players wearing full face shields and no mouthguards.

CONCLUSIONS

The use of a full face shield compared with half face shield by intercollegiate ice hockey players significantly reduced the playing time lost because of concussion, suggesting that concussion severity may be reduced by the use of a full face shield.

Sumatriptan responsiveness and clinical, psychiatric and psychologic features in migraine patients

OBJECTIVE

To compare sumatriptan responders and nonresponders in a migraine population with regard to a number of clinical, psychiatric and psychologic features.

METHODS

Patients were drawn from a referral headache clinic population, and classified as responders or nonresponders. Clinical features were assessed by a written questionnaire. The lifetime prevalence of several psychiatric disorders was determined by the National Institute of Mental Health diagnostic interview schedule and personality factors were measured by the 16 Personality Factors (16PF) Questionnaire.

RESULTS

Nonresponders indicated less influence on their migraine by menstrual factors, had a higher lifetime prevalence of generalized anxiety, and showed 16PF scores indicating greater shyness, self-sufficiency and perfectionism. Nonresponders were also more imaginative and less socially outgoing.

CONCLUSION

Although they must be interpreted with caution due to small sample size and the multiple comparisons made, our results indicate that there may be differences between sumatriptan responders and nonresponders with regard to a number of clinical, psychiatric and psychologic factors. These results suggest that biological differences exist between the two patient groups which likely account for both the differences in their responses to sumatriptan and in the clinical features noted above.

Over-expression of the cercosporin facilitator protein, CFP, in Cercospora kikuchii up-regulates production and secretion of cercosporin

CFP (cercosporin facilitator protein), a light-regulated gene from the soybean fungal pathogen Cercospora kikuchii, encodes the putative major facilitator transporter of the fungal polyketide cercosporin. Gene disruption of CFP in C. kikuchii strain Gus-3 resulted in dramatically reduced cercosporin production and virulence, and increased sensitivity to the toxin. Two C. kikuchii transformant strains (10-1 and 10-11) that over-produce cercosporin were recovered from the complementation of CFP gene-disrupted strain Gus-3. Southern analysis revealed that these strains contained multiple genomic copies of CFP and over-expressed CFP transcript and protein. Although 10-1 and 10-11 produce and secrete significantly elevated levels of cercosporin, they exhibit wild-type resistance to cercosporin, and maintain a wild-type pattern of light-regulated toxin accumulation. Restoration of wild-type cercosporin resistance in 10-1 and 10-11 suggests that CFP does contribute substantially to cercosporin resistance via toxin secretion. The three-fold increase in toxin accumulation, predominantly associated with the mycelium fraction of these CFP multi-copy strains, suggests that CFP may also have a significant, but unknown, role in regulating toxin production.

Glassy spin dynamics in non-fermi-liquid UCu5-xPdx, x = 1.0 and 1.5

Local f-electron spin dynamics in the non-Fermi-liquid heavy-fermion alloys UCu5-xPdx, x = 1.0 and 1.5, have been studied using muon spin-lattice relaxation. The sample-averaged asymmetry function G(t) indicates strongly inhomogeneous spin fluctuations and exhibits the scaling G(t,H) = G(t/H(gamma)) expected from glassy dynamics. At 0.05 K gamma(x = 1.0) = 0.35+/-0.1, but gamma(x = 1.5) = 0.7+/-0.1. This is in contrast to inelastic neutron scattering results, which yield gamma = 0.33 for both concentrations. There is no sign of static magnetism approximately greater than 10(-3)(B)/U ion in either material above 0.05 K. Our results strongly suggest that both alloys are quantum spin glasses.

Distribution of patients' paroxysmal atrial tachyarrhythmia episodes: implications for detection of treatment efficacy

INTRODUCTION

Clinical trials of treatments for paroxysmal atrial tachyarrhythmia (pAT) often compare different treatment groups using the time to first episode recurrence. This approach assumes that the time to the first recurrence is representative of all times between successive episodes in a given patient. We subjected this assumption to an empiric test.

METHODS AND RESULTS

Records of pAT onsets from a chronologic series of 134 patients with dual chamber implantable defibrillators were analyzed; 14 had experienced >10 pAT episodes, which is sufficient for meaningful statistical modeling of the time intervals between episodes. Episodes were independent and randomly distributed in 9 of 14 patients, but a fit of the data to an exponential distribution, required by the stated assumption, was rejected in 13 of 14. In contrast, a Weibull distribution yielded an adequate goodness of fit in 5 of the 9 cases with independent and randomly distributed data. Monte Carlo methods were used to determine the impact of violations of the exponential distribution assumption on clinical trials using time from cardioversion to first episode recurrence as the dependent measure. In a parallel groups design, substantial loss of power occurs with sample sizes <500 patients per group. In a cross-over design, there is insufficient power to detect a 30% reduction in episode frequency even with 300 patients.

CONCLUSION

Clinical trials that rely on time to first episode recurrence may be considerably less able to detect efficacious treatments than may have been supposed. Analysis of multiple episode onsets recorded over time should be used to avoid this pitfall.

Simulated microgravity [bed rest] has little influence on taste, odor or trigeminal sensitivity

Anecdotal evidence suggests that astronauts' perceptions of foods in space flight may differ from their perceptions of the same foods on Earth. Fluid shifts toward the head experienced in space may alter the astronauts' sensitivity to odors and tastes, producing altered perceptions. Our objective was to determine whether head-down bed rest, which produces similar fluid shifts, would produce changes in sensitivity to taste, odor or trigeminal sensations. Six subjects were rested three times prior to bed rest, three times during bed rest and two times after bed rest to determine their threshold sensitivity to the odors isoamylbutyrate and menthone, the tastants sucrose, sodium chloride, citric acid, quinine and monosodium glutamate, and to capsaicin. Thresholds were measured using a modified staircase procedure. Self-reported congestion was also recorded at each test time. Thresholds for monosodium glutamate where slightly higher during bed rest. None of the other thresholds were altered by bed rest.

The relationship between health-related quality of life and frequency of spells in patients with syncope

Chronic syncope has a wide range of symptom burden, and anecdotal data suggest substantial but variable physical and psychosocial morbidity. We hypothesized that health-related quality of life (HRQL) is impaired in syncope patients and the degree of impairment is proportional to syncope frequency. The EuroQol EQ-5D was completed by 136 patients (79 female and 57 male) with mean age 40 (SD = 17) prior to assessment. HRQL was substantially impaired in syncope patients compared to population norms in all five dimensions of health measured by the EQ-5D. In patients with six or more lifetime syncopal spells there was a significant (P < 0.001) negative relationship between the frequency of spells and overall perception of health, which was not evident in those who had a history of less than six lifetime spells. These relationships were maintained after controlling for comorbid conditions.

Randomized crossover comparison of DDDR versus VDD pacing after atrioventricular junction ablation for prevention of atrial fibrillation. The atrial pacing peri-ablation for paroxysmal atrial fibrillation (PA (3)) study investigators

BACKGROUND

Some clinical data suggest that atrial-based pacing prevents paroxysmal atrial fibrillation (AF). This study tested the hypothesis that DDDR pacing compared with VDD pacing prevents AF after atrioventricular (AV) junction ablation.

METHODS AND RESULTS

Patients were randomized to DDDR pacing (n=33) or to VDD pacing (n=34) after AV junction ablation and followed every 2 months for 6 months. Patients then crossed over to the alternate pacing mode and were followed for an additional 6 months. Primary analysis included the time to first recurrence of sustained AF (duration >5 minutes), total AF burden, and the development of permanent AF. The time to first episode of AF was similar in the DDDR group (0.37 days, 95% CI 0.1 to 1.3 days) and the VDD pacing group (0.5 days, 95% CI 0.2 to 1.7 days, P=NS). AF burden increased over time in both groups (P<0.01). At the 6-month follow-up, AF burden was 6.93 h/d (95% CI 4. 37 to 10.96 h/d) in the DDDR group and 6.30 h/d (95% CI 3.99 to 9.94 h/d) in the VDD group (P=NS). Twelve (35%) patients in the DDDR group and 11 (32%) patients in the VDD group had permanent AF within 6 months of ablation. Within 1 year of follow-up, 43% of patients had permanent AF.

CONCLUSIONS

DDDR pacing compared with VDD pacing does not prevent paroxysmal AF over the long term in patients in the absence of antiarrhythmic drug therapy after total AV junction ablation. Many patients have permanent AF within the first year after ablation.

The effect of long-term care environments on health outcomes

This study contrasts rates of mortality and of relocation to higher levels of care as well as trajectories of cognitive status, functional ability, depression, and subjective health of residents of an assisted living facility with those of a nursing home. Data were collected from medical records and face-to-face interviews with 158 residents at baseline and 4, 8, and 12 months later. All participants lived on a single long-term care campus. Logistic regression revealed that facility was not a significant predictor of mortality or relocations due to declining health. A repeated measures analysis of variance found that outcomes for people living in the two facilities did not change at different rates. These consistent findings suggest that although the assisted living and nursing home environments claim to have different philosophies of care, health outcome patterns for people living in the two environments were similar.

Temporal patterns of paroxysmal atrial fibrillation following DDDR pacemaker implantation

Paroxysmal atrial fibrillation (AF) episodes have been reported to be randomly distributed. However, because patients are not always symptomatic, it has been difficult to study temporal patterns of AF. Newer implantable pulse generators have data-logging capabilities that permit the detection and analysis of temporal patterns of AF. This study tested the hypothesis that AF episodes occur in clusters over time and that these episodes are not randomly distributed in individual patients. The date and time of 582 episodes of AF were recorded from the data logs of 16 patients with a Medtronic Thera DR followed 6 weeks and 6 and 12 months after pulse generator implant. The probability of AF recurrence and the interevent intervals between successive episodes of AF were fitted to monoexponential and Weibull distributions. A Weibull distribution best described the nonrandom distribution of AF for 67% of follow-up visits. Temporal clustering of AF (interevent intervals <24 hours) declined during follow-up (95 +/- 10%, 90 +/- 11%, and 74 +/- 28% at the 6-week and 6- and 12-month visits, respectively; p <0.05). The average duration of an episode of AF tended to increase over time (0.31 hour, 95% confidence intervals [CI] 0.17 to 0.58 hours; 0.36 hours, 95% CI 0. 17 to 0.78 hours; 0.65 hours, 95% CI 0.29 to 1.45 hours [p = 0.07] at the 6-week and 6- and 12-month visits, respectively). Paroxysmal AF recurrence is nonrandomly distributed over the long term in many patients. The temporal patterns of AF change over time after pacemaker implantation. This has implications for the selection of study end points in AF clinical trials.

Chinook winds and migraine headache

OBJECTIVE

To determine the effects of chinook weather conditions on probability of migraine headache onset.

BACKGROUND

Many migraineurs believe weather to be a trigger factor for their headaches; however, there is little supportive evidence in the literature. Migraineurs in the southern part of the Canadian province of Alberta frequently report that chinooks, warm westerly winds specific to the region, trigger their headaches.

METHOD

Weather data from Environment Canada were used to designate each calendar day during the study period as a chinook, prechinook, or nonchinook day. Headache data were collected from 75 patient diaries from the University of Calgary Headache Research Clinic. Individual and multiple logistic regression models were used to determine if the weather conditions affected the probability of migraine onset.

RESULTS

The probability of migraine onset was increased on both prechinook days (odds ratio 1.24; 95% CI 1.08 to 1.42) and on days with chinook winds (1.19; 1.02 to 1.39) compared with nonchinook days. Analysis of chinook wind velocities revealed that for chinook days, the relative risk of migraine onset was increased only on high-wind chinook days (velocity > 38 km/h) (odds ratio 1.41; 95% CI 1.06 to 1.88). A subset of individuals was sensitive to high-wind chinook days, and another subset was only sensitive to prechinook days. Only two patients were sensitive to both weather conditions, and the majority of patients was not sensitive to either. Neither weather condition had a protective effect. Increasing age was associated with high-wind chinook sensitivity (p = 0.009) but not prechinook sensitivity (p = 0.389).

CONCLUSIONS

Both prechinook and high-wind chinook days increase the probability of migraine onset in a subset of migraineurs. Because few subjects were found to be sensitive to both weather types, the mechanisms for these weather effects may be independent. This is supported by the presence of an age interaction for high-wind chinook days but not for prechinooks day.

Head and neck injuries among ice hockey players wearing full face shields vs half face shields

CONTEXT

Speculation exists that use of a full face shield by ice hockey players may increase their risk of concussions and neck injuries, offsetting the benefits of protection from dental, facial, and ocular injuries, but, to our knowledge, no data exist regarding this possibility.

OBJECTIVE

To determine the risk of sustaining a head or neck injury among intercollegiate ice hockey players wearing full face shields compared with those wearing half shields.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study conducted during the 1997-1998 Canadian Inter-University Athletics Union hockey season of 642 male hockey players (mean age, 22 years) from 22 teams. Athletes from 11 teams wore full face shields and athletes from 11 teams wore half face shields during play.

MAIN OUTCOME MEASURE

Reportable injury, defined as any event requiring assessment or treatment by a team therapist or physician or any mild traumatic brain injury or brachial plexus stretch, categorized by time lost from subsequent participation and compared by type of face shield.

RESULTS

Of 319 athletes who wore full face shields, 195 (61.6%) had at least 1 injury during the study season, whereas of 323 who wore half face shields, 204 (63.2 %) were injured. The risk of sustaining a facial laceration and dental injury was 2.31 (95% confidence interval [CI], 1.53-3.48; P<.001) and 9.90 (95% CI, 1.88-52.1; P = .007) times greater, respectively, for players wearing half vs full face shields. No statistically significant risk differences were found for neck injuries, concussion, or other injuries, although time lost from participation because of concussion was significantly greater in the half shield group (P<.001), than in the group wearing full shields.

CONCLUSIONS

These data provide evidence that the use of full face shields is associated with significantly reduced risk of sustaining facial and dental injuries without an increase in the risk of neck injuries, concussions, or other injuries.

Cost-utility analysis of pacemakers for the treatment of vasovagal syncope

Dual-chamber pacing is a promising treatment for patients with very frequent vasovagal syncope, but its cost utility is unknown. We report that the incremental cost per quality-adjusted life-year gained is $13,159 Canadian dollars (about $8,600 US dollars), and therefore this pacemaker therapy for vasovagal syncope has a favorable cost-utility ratio.

CFP, the putative cercosporin transporter of Cercospora kikuchii, is required for wild type cercosporin production, resistance, and virulence on soybean

Many species of the fungal genus Cercospora, including the soybean pathogen C. kikuchii, produce the phytotoxic polyketide cercosporin. Cercosporin production is induced by light. Previously, we identified several cDNA clones of mRNA transcripts that exhibited light-enhanced accumulation in C. kikuchii. Targeted disruption of the genomic copy of one of these, now designated CFP (cercosporin facilitator protein), results in a drastic reduction in cercosporin production, greatly reduced virulence of the fungus to soybean, and increased sensitivity to exogenous cercosporin. Sequence analysis of CFP reveals an 1,821-bp open reading frame encoding a 65.4-kDa protein similar to several members of the major facilitator superfamily (MFS) of integral membrane transporter proteins known to confer resistance to various antibiotics and toxins in fungi and bacteria. We propose that CFP encodes a cercosporin transporter that contributes resistance to cercosporin by actively exporting cercosporin, thus maintaining low cellular concentrations of the toxin.

Atrial pacing periablation for prevention of paroxysmal atrial fibrillation

BACKGROUND

This study tested the hypothesis that rate-adaptive atrial pacing would prevent paroxysmal atrial fibrillation (PAF) in patients with frequent PAF in the absence of symptomatic bradycardia.

METHODS AND RESULTS

Patients (n=97) with antiarrhythmic drug-refractory PAF received a Medtronic Thera DR pacemaker 3 months before planned AV node ablation. Patients were randomized to no pacing (n=48) or to atrial rate-adaptive pacing (n=49). After a 2-week stabilization period, patients were followed up for an additional 10 weeks. The time to first recurrence of sustained PAF, the interval between successive episodes of PAF, and the frequency of PAF were compared between the 2 groups in intention-to-treat analysis. Time to first episode of sustained PAF was similar in the no-pacing (4.2 days; 95% CI, 1.8 to 9.5) and the atrial-pacing (1.9 days; 95% CI, 0.8 to 4.6; P=NS) groups. PAF burden was lower in the no-pacing (0.24 h/d; 95% CI, 0.10 to 0.56) than in the atrial-pacing (0.67 h/d; 95% CI, 0.30 to 1.52; P=0.08) group. Paired crossover analysis in 11 patients revealed that time to first PAF was shorter during atrial pacing (1.6 days; 95% CI, 0.6 to 4.9) than with no pacing (6.0 days; 95% CI, 2.4 to 15.0; P=0.13), and PAF burden was greater during atrial pacing (1.00 h/d; 95% CI, 0.35 to 2.91) than with no pacing (0.32 h/d; 95% CI, 0.09 to 1.13; P<0.016).

CONCLUSIONS

Atrial rate-adaptive pacing does not prevent PAF over the short term in patients with antiarrhythmic drug-resistant PAF without symptomatic bradycardia.

Statistical issues encountered in the comparison of health-related quality of life in diseased patients to published general population norms: problems and solutions

The objectives of this study were (1) to illustrate the statistical problems encountered when comparing health-related quality of life (HRQL) measured by the Medical Outcome Study Short Form-36 (SF-36) in a diseased group to general population norms, and (2) to define age- and gender-standardized dichotomous indicator variables for each health concept and show that these indicator variables facilitate comparisons between the diseased sample and the general population. Our "diseased" group consisted of 136 sequentially consenting patients referred to the syncope clinic for assessment and treatment. Participants completed the SF-36 questionnaire before undergoing diagnostic testing. General population norms for the SF-36 are available from the responses of 2474 participants in the National Survey of Functional Health Status, conducted in 1990 in the United States. Comparison of the SF-36 in a diseased sample with general population norms is difficult, owing to skewed and unusual distributions in both groups. In addition, making comparisons within age and gender strata is difficult if the within strata sample size is small. We propose a dichotomous indicator variable for each health concept that classifies an individual as having impaired health if he or she scored lower than the 25th percentile for the appropriate age and gender general population strata. By definition, the prevalence of impaired health in the general population is 25% for all eight health concepts. Comparison between the eight health-concept variables is easy because the population norm is the same for each of them. These indicator variables are age and gender adjusted, so that even if the sample did not have the age and gender distribution as the general population, comparisons can still be made with the value of 25.

Behavior sequences of long-term care residents and their social partners

OBJECTIVES

This study examines similarities and differences in social interactions of residents of an assisted living facility and those of a nursing home. Given increasingly popular alternative models of long-term care such as assisted living, the study seeks to identify how these long-term care settings differentially promote dependence and independence among their residents.

METHODS

Data were collected during 256 observations of 64 residents and their social partners at meal times in public areas. Sequences of antecedent and response behaviors relating to independence and dependence in the two different long-term care settings were examined.

RESULTS

Social partners responded consistently to behavior of long-term care residents, and the behavior of residents was consistently affected by that of their social partners. These sequential interactions were not affected by setting.

DISCUSSION

Differences in the nursing home and assisted living facilities' stated philosophies of care were not manifested in the interactions of their staff and residents.

The translocation-associated tox1 locus of Cochliobolus heterostrophus is two genetic elements on two different chromosomes

Previously, Tox1 was defined as a single genetic element controlling the difference between races of Cochliobolus heterostrophus: race T is highly virulent on T-cytoplasm corn and produces the polyketide T-toxin; race O is weakly virulent and does not produce T-toxin. Here we report that Tox1 is two loci, Tox1A and Tox1B, on two different chromosomes. Evidence for two loci derives from: (1) the appearance of 25% Tox+ progeny in crosses between induced Tox1(-) mutants, one defective at Tox1A, the other at Tox1B; (2) the ability of Tox1A- + Tox1B- heterokaryons to complement for T-toxin production; and (3) electrophoretic karyotypes proving that Tox1(-) mutations are physically located on two different chromosomes. Data showing Tox1 as a single genetic element are reconciled with those proving it is two loci by the fact that Tox1 is inseparably linked to the breakpoints of a reciprocal translocation; the translocation results in a four-armed linkage group. In crosses where the translocation is heterozygous (i.e., race T by race O), all markers linked to the four-armed intersection appear linked to each other; in crosses between induced Tox1(-) mutants, complications due to the translocation are eliminated and the two loci segregate independently.

Evaluation of the bias in using the time to the first event when the inter-event intervals have a Weibull distribution

Currently the analysis of clinical trials for treatment of paroxysmal atrial fibrillation (PAF) relies on the assumption that the events are distributed according to a Poisson distribution. We contend that the occurrence of PAF events are clearly not Poisson and tend to occur in clusters. A candidate parametric model of the inter-event interval, the Weibull distribution, is presented. When the events are distributed according to a Poisson distribution, the time to the first event (TFE) has the same distribution as the inter-event intervals (IEI) due to the 'memoryless' property of the Poisson distribution, hence the TFE can be used instead of the IEI. When the events do not form a Poisson distribution, the TFE does not have the same distribution as the IEI. We show that for the Weibull distribution, when the TFE is used to model the IEI, both the mean and the survivor distribution are biased. The bias in the survivor function is a function both of time and the parameters of the distribution. Therefore when two groups have different parameters for their distributions (as in the case of different treatment effects), the discrepancy between the survivor distribution of the IEI and the survivor distribution of the TFE is affected differentially. We demonstrate the low coverage probabilities of the mean and the survivor function which result when the underlying distribution is Weibull with shape parameter kappa < 1.0. It is likely that this problem will arise for other clustered event processes. This suggests that careful empirical investigation of the distribution of IEI for recurrent events is necessary before choosing to analyse the data using the TFE.