Peak physiologic responses to arm and leg ergometry in male and female patients with airflow obstruction

STUDY OBJECTIVE: To investigate differences in work capacity for the arms and legs in patients with moderate-to-severe COPD. DESIGN: Cross-sectional investigation. PATIENTS: One hundred twenty-four patients (90 men and 34 women) aged 45 to 81 years with moderate-to-very severe COPD. FEV(1) ranged from 0.70 to 2.79 L/min (FVC, 1.73 to 5.77 L; FEV(1)/FVC, 24 to 69%). All patients were in stable condition at the time of testing and receiving a stable drug regime. MEASUREMENTS: Each patient completed a demographic and medical history questionnaire, pulmonary function studies (spirometry, lung volumes, and diffusion capacity), peak exercise ergometry with gas exchange for the arms and legs; they also rated their subjective assessment of perceived dyspnea and extremity fatigue using Borg scores during exercise. RESULTS: Patients were of comparable age, with men taller and heavier than women. Smoking history was significantly less for women (47.9 pack-years vs 66.6 pack-years for men) even though each group presented with equivalent age (p > 0.05). Women were less obstructed than men, with FEV(1)/FVC (mean +/- SD) of 46.5 +/- 10.9% vs 40.2 +/- 9.3%, respectively. Ventilatory limitation during exercise was noted for all patients studied. Peak work capacity was greater for men, and leg peak responses were greater than arm values for each gender. As airway obstruction increased, work capacity became more limited. Peak arm work achieved was 38.9 +/- 19.6 W, oxygen uptake (VO(2)) was 903.9 +/- 263.5 mL/min, and minute ventilation (VE) was 33.7 +/- 9.5 L. Peak leg work value was 62.9 +/- 24.8 W, VO(2) was 1,091.4 +/- 321.5 mL/min, and VE was 39.3 +/- 12.0 L. Hence, arm values were 62%, 83%, and 85% of the measured leg values, respectively. Dyspnea and extremity effort scores were similar for men and women, and for arms and legs. Regression analysis was used to derive prediction equations for arm work from measured leg ergometry testing. For watts of work, a three-variable model emerged explaining 66% of the variance; VO(2) yielded a four-variable model with 80% of the variance explained; and VE yielded a three-variable model explaining 72% of the variance. CONCLUSION: Arm work is reduced by 38% that of the legs, while more modest reductions are noted for VO(2) and VE, suggesting greater mechanical efficiency for leg work as compared to arm work. These data also suggest greater metabolic demand for respiratory muscles and arm ergometry. Dyspnea and extremity Borg scores were equivalent for each modality and level of airway obstruction studied, suggesting that perception plays an important role in limiting exercise, and that a threshold for termination of exercise may exist. Further, peak leg ergometry results can be used with pulmonary function indexes to predict peak arm workload in watts, VO(2), and VE. These data may be used to assist the clinician in prescribing rehabilitation or estimating arm exercise ability when arm testing is unavailable.     

Comparison between 60 matched pairs of postmenopausal black and white women: analysis of risk factors related to bone mineral density

PURPOSE: Osteoporosis is a systemic disease in which bone density is reduced, leading to weakness of the skeleton and increased vulnerability to fractures. The purpose of this study was to compare known or suspected risk factors (medical, gynecological, and lifestyle characteristics) related to bone loss between 60 matched pairs of black and white postmenopausal women. METHODS: The two racial groups were matched one for one on selective anthropometric variables [age (years), standing height (cm), and body weight (kg)] in order to equate age and body size between groups. Information on risk factors was obtained from an orally administered questionnaire and body composition variables (in addition to those used for matching) assessed by anthropometry and total body dual energy X-ray absorptiometry (DXA). Four skinfold sites (chest, triceps, mid-axillary, and abdomen) were measured with Harpendon calipers and four body circumferences (chest, forearm contracted, waist, and gluteal) were assessed with a Gulick tape. DXA radius, spine, femur, and whole body measurements were obtained on a Hologic QDR-2000 with software version 7.20. RESULTS: White women reported significantly higher proportions of alcohol use, family history of broken bones, and a greater utilization of hormones, calcium and vitamins than did black women. Black women reported a greater numbers who had other diseases (i.e., overactive thyroid, diabetes, rheumatoid arthritis, or kidney stones). Although age and body weight were similar in both groups, black women had greater lean tissue and less body fat than white women. Blacks had significantly higher bone mineral density across all body sites with the exception of the mid- and ultra-distal radius. CONCLUSION: On the basis of these data, it was concluded that part of the difference often observed in bone density between black and white postmenopausal women might be due to lifestyle factors.     

Role of Resistant Starch in Improving Gut Health,Adiposity, and Insulin Resistance

The realization that low–glycemic index diets were formulated using resistant starch led to more than a decade of research on the health effects of resistant starch. Determination of the metabolizable energy of the resistant starch product allowed for the performance of isocaloric studies. Fermentation of resistant starch in rodent studies results in what appears to be a healthier gut, demonstrated by increased amounts of short-chain fatty acids, an apparent positive change in the microbiota, and increased gene expression for gene products involved in normal healthy proliferation and apoptosis of potential cancer cells. Additionally, consumption of resistant starch was associated with reduced abdominal fat and improved insulin sensitivity. Increased serum glucagon-like peptide 1 (GLP-1) likely plays a role in promoting these health benefits. One rodent study that did not use isocaloric diets demonstrated that the use of resistant starch at 8% of the weight of the diet reduced body fat. This appears to be approximately equivalent to the human fiber requirement. In human subjects, insulin sensitivity is increased with the feeding of resistant starch. However, only 1 of several studies reports an increase in serum GLP-1 associated with resistant starch added to the diet. This means that other mechanisms, such as increased intestinal gluconeogenesis or increased adiponectin, may be involved in the promotion of improved insulin sensitivity. Future research may confirm that there will be improved health if human individuals consume the requirement for dietary fiber and a large amount of the fiber is fermentable.     

Comparison of dietary intake of overweight postpartum mothers practicing breastfeeding or formula feeding

Background

Weight gain in the postpartum period is a risk factor for long-term obesity. Investigations of dietary intake among lactating and nonlactating overweight women might identify nutritional concerns specific to this population.

Objective

To compare nutrient, meal, and snack intakes, food-group servings and prevalence of dieting among fully breastfeeding (BF), mixed breast and formula feeding (MF), and formula feeding (FF) overweight and obese women. The second aim was to compare nutrient intakes and food-group servings to the Dietary Reference Intake and MyPyramid recommendations, respectively.

Design

Data were collected from September 2004 through April 2006 in Durham, NC. Infant feeding practices and dietary information were collected on 450 women between 6 and 9 weeks postpartum. Two 24-hour dietary recalls were completed by phone, using Nutrition Data Systems for Research. Analysis of covariance was used to compare infant feeding groups in dietary quality (nutrient intake per 1,000 kcal) and food-group servings, controlling for prepregnancy body mass index, race, age, education, income, and marital status. χ² analysis was performed to determine differences in meal and snack intake and dieting among infant feeding groups.

Results

BF women consumed more energy (2,107±50 kcal) than MF (1,866±56 kcal) or FF (1,657±50 kcal) women (P<0.001). Adjusted nutrient intake did not differ between groups. All groups were at risk for inadequate intakes of vitamins A, E, C, and folate and did not meet recommended servings of all food groups. BF women consumed lunch and snacks more frequently, were less likely to diet, and reported higher intakes of grains and desserts than MF and FF women.

Conclusions

To help increase intakes of nutrients lacking in the diet and prevent postpartum weight gain, overweight women should be encouraged to increase fruits, vegetables, low-fat dairy, whole grains, legumes, and healthy types of fat, while decreasing refined grains, regular soda, sweetened beverages, and desserts.     

Lateral condylar resection for bunionette.

Lateral condylar resection operations were performed in 21 feet in 16 patients with painful bunionettes. The mean follow-up period (examination and roentgenography) was 6.4 years (range, 2.3-12.4 years). The average forefoot score improved from 40.3 +/- 13.5 points to 68.3 +/- 11.7 points of a possible 75 points. The overall results were considered good in 15 feet, fair in three, and poor in three. The causes of failure were inadequate amount of resection, metatarsophalangeal joint subluxation, and severe forefoot splaying. Complications were infection, toe hypesthesia, and metatarsophalangeal joint subluxation. One patient required reoperation. Lateral condylar resection is simple and effective for most patients with bunionette, but limitations are recognized.     

Hemodynamic collapse during left ventricular lead implantation

Hypotension as a procedural complication during cardiac resynchronization therapy (CRT) implantation was reported in the initial randomized clinical trials. However, this phenomenon is not well characterized. We reviewed our CRT implantation experience to better understand this issue. There were 105 patients who underwent left ventricular lead implantation for CRT. Four patients had marked hypotension (systolic blood pressure < or = 50 mmHg) during the procedure. All had a history of hypertension and diabetes mellitus and were pacemaker dependent. Two had normal renal function, one had moderate renal insufficiency, and one was on dialysis. Three patients had ischemic cardiomyopathy. All had left ventricular ejection fraction < or =20% and were in New York Heart Association class III. Propofol and midazolam were used for sedation as standard protocol. Two patients had sudden hypotension when the coronary sinus was being cannulated, and two patients experienced sudden hypotension during left ventricular pacing. Cardiac tamponade as a possible cause was ruled out by echocardiography. We discuss possible mechanisms of sudden hemodynamic collapse during CRT implantation.     

Age-specific effects of vaccine egg adaptation and immune priming on A(H3N2) antibody responses following influenza vaccination

A(H3N2) influenza vaccine effectiveness (VE) was low during the 2016–19 seasons and varied by age. We analyzed neutralizing antibody responses to egg- and cell-propagated A(H3N2) vaccine and circulating viruses following vaccination in 375 individuals (aged 7 months to 82 years) across all vaccine-eligible age groups in 3 influenza seasons. Antibody responses to cell- versus egg-propagated vaccine viruses were significantly reduced due to the egg-adapted changes T160K, D225G, and L194P in the vaccine hemagglutinins. Vaccine egg adaptation had a differential impact on antibody responses across the different age groups. Immunologically naive children immunized with egg-adapted vaccines mostly mounted antibodies targeting egg-adapted epitopes, whereas those previously primed with infection produced broader responses even when vaccinated with egg-based vaccines. In the elderly, repeated boosts of vaccine egg-adapted epitopes significantly reduced antibody responses to the WT cell–grown viruses. Analysis with reverse genetic viruses suggested that the response to each egg-adapted substitution varied by age. No differences in antibody responses were observed between male and female vaccinees. Here, the combination of age-specific responses to vaccine egg-adapted substitutions, diverse host immune priming histories, and virus antigenic drift affected antibody responses following vaccination and may have led to the low and variable VE against A(H3N2) viruses across different age groups.