Effects of Vasopressin on Sweat Rate and Composition in Patients with Diabetes Insipidus and Normal Controls

Baseline sweat rate and concentrations of sodium, chloride, and potassium, and the effect of exogenous vasopressin on these parameters were determined in 13 patients with acquired diabetes insipidus (ADI), four patients with nephrogenic diabetes insipidus (NDI), three subjects with cystic fibrosis, and age- and sex-matched controls. The four patients with NDI did not differ from the controls with respect to baseline sweat rate, but baseline sodium, chloride, and potassium concentrations were significantly elevated. In addition, parenteral vasopressin caused a significant decrease in sweat rate (p < .01) while the electrolyte concentrations remained unchanged. This indicates that vasopressin may also have an effect on electrolyte reabsorption in NDI patients. Alternatively, the amount of sweat precursor fluid may have been reduced. The patients with ADI did not differ from the controls with respect to baseline data, and parenteral vasopressin had no effect on their sweat rate and composition. Likewise, vasopressin had no effect in controls or patients with cystic fibrosis. We conclude that, except in patients with NDI, vasopressin does not play a significant role in the regulation of human eccrine sweating. Sweat gland physiology appears to be different in patients with NDI and in them vasopressin may have a significant effect on sweat

Lymphocyte Subpopulation Number and Function in Infancy

Normal values for percentages of lymphocyte subpopulations and functional responses to mitogen stimulation in infancy are not well established. In the present study, lymphocyte subpopulations were examined in umbilical cord blood samples and in peripheral blood samples drawn before 7 and 24 months of age (mean age 10.4 months) from a healthy population of infants born in Tucson, Arizona. Results indicate significant increases occurred from birth to later infancy in the percentages of total T cells (CD3), T-cell subsets (CD4, CD8) and B cells (CD20). The CD4/CD8 ratio and the functional responses to ConA and PWM mitogens significantly decreased from birth to later infancy. PHA responsiveness did not show a significant change. Results from cross-sectional analyses (n=271) were supported in a smaller longitudinal subset (n=37). There were no detectable ethnic- or gender-related differences in cord blood or samples obtained in later infancy. The normal values established in this study will be useful in studies of immune-system maturation and in the clinical evaluation of newborns, infants, and toddlers suspected of either acquired or congenital immune-deficiency states

Prematurity and respiratory outcomes program (PROP): Study protocol of a prospective multicenter study of respiratory outcomes of preterm infants in the United States

Background With improved survival rates, short- and long-term respiratory complications of premature birth are increasing, adding significantly to financial and health burdens in the United States. In response, in May 2010, the National Institutes of Health (NIH) and the National Heart, Lung, and Blood Institute (NHLBI) funded a 5-year $18.5 million research initiative to ultimately improve strategies for managing the respiratory complications of preterm and low birth weight infants. Using a collaborative, multi-disciplinary structure, the resulting Prematurity and Respiratory Outcomes Program (PROP) seeks to understand factors that correlate with future risk for respiratory morbidity. Methods/Design The PROP is an observational prospective cohort study performed by a consortium of six clinical centers (incorporating tertiary neonatal intensive care units [NICU] at 13 sites) and a data-coordinating center working in collaboration with the NHLBI. Each clinical center contributes subjects to the study, enrolling infants with gestational ages 23 0/7 to 28 6/7 weeks with an anticipated target of 750 survivors at 36 weeks post-menstrual age. In addition, each center brings specific areas of scientific focus to the Program. The primary study hypothesis is that in survivors of extreme prematurity specific biologic, physiologic and clinical data predicts respiratory morbidity between discharge and 1 year corrected age. Analytic statistical methodology includes model-based and non-model-based analyses, descriptive analyses and generalized linear mixed models. Discussion PROP incorporates aspects of NICU care to develop objective biomarkers and outcome measures of respiratory morbidity in the <29 week gestation population beyond just the NICU hospitalization, thereby leading to novel understanding of the nature and natural history of neonatal lung disease and of potential mechanistic and therapeutic targets in at-risk subjects

Pediatric respiratory medicine, 2nd ed./ Edit.: Lynn M. Taussig (et al)

xxiii, 1118 hal.: ill, tab.; 27 cm

Bronchodilator response during acute viral bronchiolitis in infancy

Bronchodilator responsiveness was assessed by measuring specific respiratory conductance before and after inhalation of aerosolized bronchodilator in 50 infants who had acute bronchiolitis due to respiratory syncytial virus infection. Thirty per cent of the infants showed an improvement in specific conductance. Responders could not be differentiated from nonresponders by family histories of atopy, eosinophil counts, or immunoglobulin levels in blood and nasal secretions. Eighty‐three per cent of the families and 54% of the mothers of the infants were smokers. Babies of smoking mothers had lower specific conductances than did those of nonsmoking mothers but showed no differences in bronchodilator response. The clinical significance of this bronchodilator‐responsive subgroup has yet to be defined