Corticosterone levels of Atlantic puffins vary with breeding stage and sex but are not elevated in poor foraging years.

Corticosterone (CORT) levels in seabirds fluctuate across breeding stages and in different foraging conditions. Here we use a ten-year data set to examine whether CORT levels in Atlantic puffins differ in years with high or low availability of capelin, the preferred forage species. Female puffins had higher CORT levels than males, possibly related to cumulative costs of egg production and higher parental investment. Puffins had higher CORT levels and body mass during pre-breeding than during chick rearing. Yearly mean chick growth rates were higher in years when adults had higher body mass and in years where adults brought chicks a lower percentage of non-fish (invertebrates/larval fish) food. Unlike most results from seabird species with shorter chick-rearing periods, higher CORT levels in puffins were not associated with lower capelin abundance. Puffins may suppress CORT levels to conserve energy in case foraging conditions improve later in the prolonged chick-rearing period. Alternatively, CORT levels may be lowest both when food is very abundant (years not in our sample) or very scarce (e.g., 2009 in this study), and increase when extra foraging effort will increase foraging efficiency (most years in this study). If these data primarily represent years with medium to poor foraging, it is possible that CORT responses to variation in foraging conditions are similar for puffins and other seabirds.

Cross section dependence of event rates at neutrino telescopes.

We examine the dependence of event rates at neutrino telescopes on the neutrino-nucleon cross section for neutrinos with energy above 1 PeV, and contrast the results with those for cosmic ray experiments. Scaling of the standard model cross sections leaves the rate of upward events essentially unchanged. Details, such as detector depth and cross section inelasticity, can influence rates. Numerical estimates of upward shower, muon, and tau event rates in the IceCube detector confirm these results.

Masked hypertension: a common but insidious presentation of hypertension.

A patient has masked hypertension when his office blood pressure is less than 140/90 mmHg but his ambulatory or home blood pressure readings are in the hypertensive range. Several recent studies have demonstrated that cardiovascular risk is similar between those with masked hypertension and those with sustained hypertension. The prevalence of masked hypertension in Canada is not known, but data from other countries suggest rates greater than 8%. Physicians need to use careful clinical judgment to identify and treat subjects with masked hypertension. The present review discusses masked hypertension, its importance to clinical practice and some aspects of patient management.

Self-measurement of blood pressure: accuracy, patient preparation for readings, technique and equipment.

OBJECTIVE: Self-measurement of blood pressure is commonly performed by those persons with hypertension and is advocated in many national hypertension guidelines. We examined accuracy of readings, patient knowledge, and preparation for readings, technique and equipment. DESIGN: The study was a prospective observational design. Sixty-nine hypertensive patients were recruited from a tertiary referral center and by newspaper advertisement. All patients had previously self-measured their blood pressure. The patients initially measured their blood pressure under direct supervision in a clinic using their usual preparation, technique and their own equipment. Then after a five-min rest, blood pressures were measured twice both by research nurse and the patient in an alternating sequence. The nurse used a standardized blood pressure measurement technique. RESULTS: Inadequate patient knowledge and performance of measurement technique and inaccurate equipment was common. The average initial patient systolic reading prior to the five-minute rest was higher than that of the trained nurse (9.1 +/- 13 mmHg systolic, p < 0.001 and 1.5 +/- 8.0 mmHg diastolic, p = 0.12). Almost half (42%) of the initial patient blood pressure readings differed in classification of hypertension/normotension from the nurse. The difference between the patient and nurse readings after the five-min rest was 3.8 +/- 11.8 / 1.1 +/- 6.8 mmHg. CONCLUSIONS: Care must be taken in interpreting patient self-measured blood pressure unless there has been adequate training and assessment of patient and equipment accuracy. Studies of health care professionals reveal similar problems therefore widespread efforts to standardize blood pressure measurement are necessary.

The 2000 Canadian recommendations for the management of hypertension: part two--diagnosis and assessment of people with high blood pressure.

OBJECTIVE: To provide updated, evidence-based recommendations for the diagnosis and assessment of high blood pressure in adults. OPTIONS: For people with high blood pressure, the assignment of a diagnosis of hypertension depends on the appropriate measurement of blood pressure, the level of the blood pressure elevation, the duration of follow-up and the presence of concomitant vascular risk factors, target organ damage and established atherosclerotic diseases. For people diagnosed with hypertension, defining the overall risk of adverse cardiovascular outcomes requires laboratory testing, a search for target organ damage and an assessment of the modifiable causes of hypertension. Out-of-clinic blood pressure assessment and echocardiography are options for selected patients. OUTCOMES: People at increased risk of adverse cardiovascular outcomes and were identified and quantified. EVIDENCE: Medline searches were conducted from the period of the last revision of the Canadian recommendations for the management of hypertension (May 1998 to October 2000). Reference lists were scanned, experts were polled, and the personal files of the subgroup members and authors were used to identify other studies. All relevant articles were reviewed and appraised, using prespecified levels of evidence, by content experts and methodological experts. VALUES: A high value was placed on the identification of people at increased risk of cardiovascular morbidity and mortality. BENEFITS, HARMS AND COSTS: The identification of people at higher risk of cardiovascular disease will permit counselling for lifestyle manoeuvres and the introduction of antihypertensive drugs to reduce blood pressure for patients with sustained hypertension. In certain settings, and for specific classes of drugs, blood pressure lowering has been associated with reduced cardiovascular morbidity and/or mortality. RECOMMENDATIONS: The present document contains detailed recommendations pertaining to aspects of the diagnosis and assessment of patients with hypertension, including the accurate measurement of blood pressure, criteria for the diagnosis of hypertension and recommendations for follow-up, routine and optional laboratory testing, assessment for renovascular hypertension, home and ambulatory blood pressure monitoring, and the role of echocardiography in hypertension. VALIDATION: All recommendations were graded according to strength of the evidence and voted on by the Canadian Hypertension Recommendations Working Group. Only the recommendations achieving high levels of consensus are reported here. These guidelines will be updated annually. ENDORSEMENT: These recommendations are endorsed by the Canadian Hypertension Society, The Canadian Coalition for High Blood Pressure Prevention and Control, The College of Family Physicians of Canada, The Heart and Stroke Foundation of Canada, The Adult Disease Division and Bureau of Cardio-Respiratory Diseases and Diabetes at the Centre for Chronic Disease Prevention and Control of Health Canada.

Is usual measurement of blood pressure meaningful?

BACKGROUND: Standardized measurement of blood pressure is widely recommended but rarely applied in usual clinical practice. OBJECTIVE: To determine the differences resulting from physicians using standardized and usual (casual) techniques for measurement of blood pressure. METHODS: Blood pressures measured by a research nurse, ambulatory blood pressure monitoring and echocardiographic estimation of left ventricular mass index were used as standards for comparison. RESULTS: Use of casual technique resulted in blood pressure readings higher than those obtained by standardized technique, namely 6.2 (3.1-9.3) systolic and 3.9 (2.4-5.4) diastolic mmHg [means (95% confidence intervals)], and readings that were more variable. Sixty-two patients (42%) were classified normotensive by standardized techniques but hypertensive by physicians casual technique. When standardized technique was used 22 patients (15%) were classified hypertensive but blood pressure readings in normal range were obtained by usual technique. Measurements obtained using standardized technique were less variable and were significantly correlated to left ventricular mass index. CONCLUSION: Using standardized technique is important if one is to classify the blood pressures of patients correctly. Use of usual or casual technique results in higher, more variable readings that are not related to left ventricular mass index. Results of this study strongly support recommendations that standardized technique should be used for assessing the cardiovascular risk of all adult patients.

Lifestyle modifications to prevent and control hypertension. 3. Recommendations on alcohol consumption. Canadian Hypertension Society, Canadian Coalition for High Blood Pressure Prevention and Control, Laboratory Centre for Disease Control at Health Canada, Heart and Stroke Foundation of Canada.

OBJECTIVE: To provide updated, evidence-based recommendations concerning the effects of alcohol consumption on the prevention and control of hypertension in otherwise healthy adults (except pregnant women). OPTIONS: There are 2 main options for those at risk for hypertension: avert the condition by limiting alcohol consumption or by using other nonpharmacologic methods, or maintain or increase the risk of hypertension by making no change in alcohol consumption. The options for those who already have hypertension include decreasing alcohol consumption or using another nonpharmacologic method to reduce hypertension; commencing, continuing or intensifying antihypertensive medication; or taking no action and remaining at increased risk of cardiovascular disease. OUTCOMES: The health outcomes considered were changes in blood pressure and in morbidity and mortality rates. Because of insufficient evidence, no economic outcomes were considered. EVIDENCE: A MEDLINE search was conducted for the period 1966-1996 with the terms ethyl alcohol and hypertension. Other relevant evidence was obtained from the reference lists of articles identified, from the personal files of the authors and through contacts with experts. The articles were reviewed, classified according to study design, and graded according to the level of evidence. VALUES: A high value was placed on the avoidance of cardiovascular morbidity and premature death caused by untreated hypertension. BENEFITS, HARMS AND COSTS: A reduction in alcohol consumption from more than 2 standard drinks per day reduces the blood pressure of both hypertensive and normotensive people. The lowest overall mortality rates in observational studies were associated with drinking habits that were within these guidelines. Side effects and costs were not measured in any of the studies. RECOMMENDATIONS: (1) It is recommended that health care professionals determine how much alcohol their patients consume. (2) To reduce blood pressure in the population at large, it is recommended that alcohol consumption be in accordance with Canadian low-risk drinking guidelines (i.e., healthy adults who choose to drink should limit alcohol consumption to 2 or fewer standard drinks per day, with consumption not exceeding 14 standard drinks per week for men and 9 standard drinks per week for women). (3) Hypertensive patients should also be advised to limit alcohol consumption to the levels set out in the Canadian low-risk drinking guidelines. VALIDATION: These recommendations are similar to those of the World Hypertension League, the National High Blood Pressure Education Program Working Group on Primary Prevention of Hypertension and the previous recommendations of the Canadian Coalition for High Blood Pressure Prevention and Control and the Canadian Hypertension Society. They have not been clinically tested. The low-risk drinking guidelines are those of the Addiction Research Foundation of Ontario and the Canadian Centre on Substance Abuse. SPONSORS: The Canadian Hypertension Society, the Canadian Coalition for High Blood Pressure Prevention and Control, the Laboratory Centre for Disease Control at Health Canada, and the Heart and Stroke Foundation of Canada. The low-risk drinking guidelines have been endorsed by the College of Family Physicians of Canada and several provincial organizations.

Dislocation of hip in myelomeningocele. The McKay hip stabilization.

We reviewed the clinical and radiographic results of varus osteotomy of the proximal aspect of the femur and transfer of the adductor and external oblique muscles (the McKay procedure) in thirty-four children (sixty-six hips) who had an unstable hip secondary to a myelomeningocele at the middle or caudad lumbar level. the average age at the time of the operation was twenty months (range, seven to forty-two months). The average duration of follow-up was 10.9 years (range, 0.7 to 20.0 years). An open reduction was performed in ten hips. None of the children had had any previous operative treatment. The index operation helped to maintain the stability of thirty-seven of the fifty-one hips twenty-six children who remained neurologically stable: seventeen of nineteen hips that were at risk, two of three hips with acetabular dysplasia, fifteen of sixteen subluxated hips, one of three dislocated hips that had been previously reduced with a Pavlik harness, one of two dislocatable hips, and one of seven previously untreated dislocated hips. The index operation was not successful for one dislocated hip that had been treated with closed reduction and application of a spica cast. The operation was a success for eight of the fifteen hips in eight children who had a progressive loss of neurological function: three of five hips that were at risk, one hip with acetabular dysplasia, two of four subluxated hips, one of two that had been previously reduced with a Pavlik harness, and one dislocatable hip. Two dislocated hips redislocated. Initially the index operation was performed on all children who had a myelomeningocele at the third or fourth lumbar level. Recent data have shown that the hips in these children are not all at risk, and we now perform the operation only if there is documented instability of the hip.

Self-measurement of blood pressure: assessment of equipment. Canadian Coalition for High Blood Pressure Prevention and Control.

Equipment for the self-measurement of blood pressure is readily available to consumers. These devices use one or more surrogate (indirect) measures of pressure to estimate systolic and diastolic blood pressure. Manual auscultatory devices using stethoscope and sphygmomanometer have been adapted for home use, but a variety of automated devices based on auscultation, oscillometry, and other techniques are available and may be more suitable for individuals who have limited vision, hearing or dexterity. Despite the existence of voluntary evaluation protocols and mandatory manufacturing standards, blood pressure readings from some automatic devices may not be accurate. Some devices are packaged with insufficient information to ensure proper use, and most individuals need some form of guidance in their use and calibration testing. If self-measurement of blood pressure is to be of benefit, the health care professional must recommend only those devices that are accurate and suitable to the patient or client. The Canadian Coalition for High Blood Pressure Prevention and Control will endeavour to develop a regular means by which health care professionals can keep informed of available devices for blood pressure self-measurement.

Self-measurement of blood pressure: recommendations of the Canadian Coalition for High Blood Pressure Prevention and Control.

OBJECTIVE: To provide health care professionals with guidelines on the use of blood pressure self-measurement. METHODS: Recommendations were devised after consideration of expert reviews and guidelines, personal files, international standards documents, personal communication with investigators and the results of a MEDLINE search (1966-94) using the term 'blood pressure determination'. BENEFITS, HARMS, COSTS: Self-measurement of blood pressure can be used to detect white coat hypertension, monitor changes in blood pressure closely, more rapidly achieve desired blood pressure goals, increase adherence to antihypertensive therapy and improve patient self-reliance. However, self-measured blood pressure readings may be misleading because there is insufficient normative, prognostic and outcome data and because some patients may not take accurate measurements. The use of self-measurement of blood pressure has a relatively small direct cost and may result in an overall reduction in treatment costs. RECOMMENDATIONS: Self-measured blood pressure readings can be a valuable supplement to clinic (or office) blood pressure readings. However, self-measurement is appropriate neither for patients who are physically or mentally incapable of accurate assessment and interpretation of readings nor for those who do not want to participate. Patients who self-monitor blood pressure require careful training in blood pressure measurement and instruction on the recording and interpretation of blood pressure readings. Advice to patients using monitoring equipment must take into account the needs and abilities of the patient. Although only a few electronic devices for the self-measurement of blood pressure have met recommended performance standards, their use may be more appropriate for some patients and the training requirements fewer than if manual devices are used. VALIDATION: The guidelines of several expert groups were examined in the preparation of these recommendations. The recommendations were presented at the World Conference on Hypertension Control in 1995 and were reviewed by the parent societies of the Canadian Coalition for High Blood Pressure Prevention and Control.

Medroxyprogesterone increases basal temperature: a placebo-controlled crossover trial in postmenopausal women.

OBJECTIVE: To assess whether temperature is increased by medroxyprogesterone (MPA) and thus whether basal temperature records could be used to determine ovulation during cyclic MPA therapy. DESIGN: A 2-month double-blind placebo-controlled crossover trial in which oral basal temperature was measured daily. SETTING: Normal human volunteers in an academic medical environment. SUBJECTS: Eleven postmenopausal women not taking gonadal hormones. INTERVENTION: Medroxyprogesterone acetate (10 mg/d) or placebo, calendar days 16 to 25, with crossover. MAIN OUTCOME MEASURES: Comparison of mean temperature days 17 to 26 during MPA versus placebo; comparison of differences between temperatures days 7 to 16 and 17 to 26 in MPA versus placebo months; and analysis for a significant monthly thermal shift. RESULTS: The mean temperatures during MPA treatment averaged 0.27 degrees C higher than during the placebo phase and showed a significant change from pretreatment to "treatment" phases during MPA but not during placebo cycles. Eight of the MPA and one of the placebo cycles showed a shift from lower to higher temperatures days 16 to 25. CONCLUSIONS: Medroxyprogesterone acetate has a physiological progesterone-like thermal effect. Therefore basal temperature data cannot reliably indicate ovulation during cyclic MPA administration.

Errors in assessment of blood pressure: patient factors.

This article reviews patient-related factors affecting blood pressure measurement and provides the scientific rationale underlying current recommendations for the measurement of blood pressure in the evaluation of hypertension. Information is included on the magnitude of errors that can occur when the recommendations are not followed. A variety of factors relating to the patient's emotions, activity, bodily function and environment cause blood pressure to fluctuate throughout the day such that peak systolic and diastolic blood pressures are often twice as high as trough levels. Many physicians fail to account for these factors when assessing a patient's blood pressure. Errors in the classification and treatment of a patient's blood pressure and the finding of labile blood pressure can occur often when patients are not adequately prepared in advance of the blood pressure measurement.

Errors in assessment of blood pressure: blood pressure measuring technique.

This article reviews the recommended techniques for accurate and reproducible blood pressure measurements. The scientific basis underlying current recommendations for blood pressure measurement is presented. Many of the current recommendations are not followed in ambulatory care clinics and this paper will show how measurement errors in excess of 15 mm Hg or more can occur. Many patients will be misclassified and treated inappropriately when errors in blood pressure measurement of this magnitude are made. Rigorous adherence to proper blood pressure measurement is necessary to evaluate a patient's risk of cardiovascular disease, and to assess the need or efficacy of antihypertensive therapy.

Errors in assessment of blood pressure: sphygmomanometers and blood pressure cuffs.

This article reviews the current recommendations on equipment when blood pressure is measured by sphygmomanometer. The scientific rationale underlying the current recommendations for selection and maintenance of blood pressure measuring equipment is presented. The errors that can occur when the recommendations are not followed are quantified whenever the data are available. Inadequate assessment and maintenance of equipment often lead to the use of faulty equipment, and as a result errors in the assessment of patients' blood pressure are likely to be common. If followed, the current guidelines for use and maintenance of equipment would remove most of the problems noted. Physicians must ensure that properly maintained and appropriate equipment is used to measure blood pressure.

Pitfalls to avoid in the measurement of blood pressure in the elderly.

Accurate, reproducible blood pressure readings are more difficult to obtain in the elderly. Elderly patients have more variable blood pressure, show a reduction in blood pressure following meals, and can have postural hypotension, discrepancies in blood pressure between arms, auscultatory gaps and 'pseudohypertension', all of which can mislead clinicians regarding these patients' usual blood pressure. Arrhythmias, particularly atrial fibrillation, make accurate blood pressure determination difficult and are more common in the elderly. Prostatic hypertrophy causing high pressure urinary retention is suggested as a common and reversible cause of hypertension in older men. Proper measurement of blood pressure in elderly patients demands additional thought and action, all of which are necessary for accurate cardiovascular risk assessment and proper therapeutic decisions. Increasing the number of visits and the number of carefully taken blood pressure readings per visit will result in a more accurate assessment of blood pressure in older patients.

Percutaneous intramedullary fixation of long bone deformity in severe osteogenesis imperfecta.

Reported here are seven patients who had severe osteogenesis imperfecta, and who were extremely fragile, with three having cardiac disease. Their age ranged between 8 and 35 months. All seven patients had unbraceable deformities. Twenty five long bones, including 14 tibiae, 10 femora, and 1 ulna underwent percutaneous intramedullary fixation. Four patients had all four lower extremity long bones operated on simultaneously. Followup was 2 to 11 years. There were no neurologic or vascular complications, compartment syndromes, growth plate problems, or transfusion requirements. All bones healed. One patient had migration of a femoral pin into the knee joint. After bracing, all patients were able to sit; five were able to stand and eventually walk. All living patients were able to be sustained until successful definitive long bone fixation could be accomplished, approximately 2 years or longer after this initial procedure. With this safe, reproducible method, early stable fixation can be provided to patients too young and/or too sick for definitive or extensive open surgery. Future treatment regimens are not compromised.

The antianginal efficacy of isosorbide dinitrate therapy is maintained during diuretic treatment.

OBJECTIVES: To determine whether the use of a diuretic would maintain the antianginal efficacy of isosorbide dinitrate during 1 week of therapy. METHODS: During continuous therapy, organic nitrates have a reduction in antianginal effectiveness and cause fluid retention. The study was a randomized, double-blind, placebo-controlled crossover design examining the effect of 1 week of daily treatment with 50 mg hydrochlorothiazide/5 mg amiloride on the antianginal effectiveness of 30 mg isosorbide dinitrate administered every 6 hours. Exercise stress testing was performed before and 3 hours after administration of isosorbide dinitrate at the start and end of the placebo and diuretic treatment phases. RESULTS: The time to onset of angina (475 +/- 35 versus 490 +/- 29 seconds, difference not significant) and to moderate angina after administration of isosorbide dinitrate (542 +/- 40 versus 566 +/- 37 seconds, difference not significant) were similar at the start and end of the diuretic phase of the study but were reduced at the end of the placebo phase (471 +/- 40 versus 410 +/- 40 seconds, p < 0.05 and 531 +/- 38 versus 466 +/- 39 seconds, p < 0.05, respectively). Total exercise time and time to onset of angina 3 hours after administration of isosorbide dinitrate were longer (p < 0.005) at the end of the diuretic phase compared with the end of the placebo phase. Patients gained weight during the placebo phase and lost weight during the diuretic phase of the study. The change in weight was inversely correlated to the change in total exercise time (r = -0.53, p < 0.05). CONCLUSIONS: Patients using a diuretic with isosorbide dinitrate maintain an increased anginal threshold and total exercise time compared with placebo. Weight change is inversely related to exercise duration, and this result is consistent with fluid retention restoring cardiac preload during nitrate use. The increased anginal threshold during concurrent isosorbide dinitrate and diuretic use may be attributable to maintenance of the organic nitrate-induced reductions in cardiac preload.