Absence of amiloride-sensitive sodium absorption in the airway of an infant with pseudohypoaldosteronism.

We report the measurement of transepithelial voltage across the nasal epithelium in a neonate with pseudohypoaldosteronism (PHA) type 1. A 5-day-old infant was seen with hyponatremia, hyperkalemia, and elevated plasma renin and aldosterone levels. Sweat Cl(-) concentration was also increased.

Effect of subunit composition and Liddle's syndrome mutations on biosynthesis of ENaC.

The epithelial Na+ channel (ENaC) is comprised of three homologous subunits: alpha, beta, and gamma, all of which are required for formation of the fully functional channel. This channel is responsible for salt reabsorption in the kidney, the airway, and the large bowel. Mutations in ENaC can cause human disease by increasing channel function in Liddle's syndrome, a form of hereditary hypertension, or by decreasing channel function in pseudohypoaldosteronism type I, a salt-wasting disease of infancy.

Efficient endocytosis of the cystic fibrosis transmembrane conductance regulator requires a tyrosine-based signal.

We previously demonstrated that the cystic fibrosis transmembrane conductance regulator (CFTR) is rapidly endocytosed in epithelial cells (Prince, L. S., Workman, R.

Cell surface expression and biosynthesis of epithelial Na+ channels.

The epithelial Na+ channel (ENaC) complex is composed of three homologous subunits: alpha, beta and gamma. Mutations in ENaC subunits can increase the number of channels on the cell surface, causing a hereditary form of hypertension called Liddle's syndrome, or can decrease channel activity, causing pseudohypoaldosteronism type I, a salt-wasting disease of infancy. To investigate surface expression, we studied ENaC subunits expressed in COS-7 and HEK293 cells.

Inhibition of the epithelial Na+ channel by interaction of Nedd4 with a PY motif deleted in Liddle's syndrome.

The epithelial Na+ channel (ENaC) plays a critical role in Na+ absorption in the kidney and other epithelia. Mutations in the C terminus of the beta or gammaENaC subunits increase renal Na+ absorption, causing Liddle's syndrome, an inherited form of hypertension. These mutations delete or disrupt a PY motif that was recently shown to interact with Nedd4, a ubiquitin-protein ligase expressed in epithelia.

Assembly of the epithelial Na+ channel evaluated using sucrose gradient sedimentation analysis.

Three subunits, alpha, beta, and gamma, contribute to the formation of the epithelial Na+ channel. To investigate the oligomeric assembly of the channel complex, we used sucrose gradient sedimentation analysis to determine the sedimentation properties of individual subunits and heteromultimers comprised of multiple subunits. When the alpha subunit was expressed alone, it first formed an oligomeric complex with a sedimentation coefficient of 11 S, and then generated a higher order multimer of 25 S.

Evidence-based practice and the role of nursing leadership.

A new term, evidence-based practice, is beginning to appear both in the healthcare literature and at professional, conferences. Its meaning, however, is not always clear, nor is its full implication for nurse administrators explained. This article provides a pragmatic definition of evidence-based practice developed in the nursing division at Baystate Medical Center, Springfield, Massachusetts.

Electrophysiological and biochemical evidence that DEG/ENaC cation channels are composed of nine subunits.

Members of the DEG/ENaC protein family form ion channels with diverse functions. DEG/ENaC subunits associate as hetero- and homomultimers to generate channels; however the stoichiometry of these complexes is unknown. To determine the subunit stoichiometry of the human epithelial Na+ channel (hENaC), we expressed the three wild-type hENaC subunits (alpha, beta, and gamma) with subunits containing mutations that alter channel inhibition by methanethiosulfonates.

Rapid endocytosis of the cystic fibrosis transmembrane conductance regulator chloride channel.

The cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is found at the apical region of exocrine epithelial cells, both at the cell surface and in an apically localized intracellular compartment. To determine if this internal pool was due to endocytosis, a technique was developed that allows the rate of CFTR internalization from the cell surface to be monitored. A two-step periodate/hydrazide biotinylation procedure was used to derivatize cell surface glycoconjugates.

Immunosuppression by glucocorticoids: inhibition of production of multiple lymphokines by in vivo administration of dexamethasone.

Glucocorticoids are extremely potent immunosuppressive agents, capable of directly affecting the function of lymphocytes. We studied the effect of in vivo dexamethasone (DEX) administration on anti-CD3-induced lymphocyte proliferation and lymphokine production in mice. To characterize the kinetics and dose responsiveness of lymphocytes to DEX, splenocytes from BALB/c mice that had received a single dose of DEX in vivo were cultured in vitro with suboptimal and optimal concentrations of anti-CD3 monoclonal antibody.

Cell surface labeling of CFTR in T84 cells.

To distinguish cystic fibrosis transmembrane conductance regulator (CFTR) at the surface of epithelial cells from that present in intracellular membranes, intact T84 cells were treated with periodate and biotin-LC-hydrazide to derivatize exposed glycoconjugates. Cell lysates were then passed over a monomeric avidin column, which allows reversible avidin-biotin binding. After washing, biotinylated molecules were eluted with 2 mM biotin.

The longitudinal relaxation time (T1) of the intracellular 23Na NMR signal in the isolated perfused rat heart during hypoxia and reoxygenation.

Each of six perfused rat hearts was subjected to 30 min of hypoxia followed by 60 min of reoxygenation. Inversion-recovery data on the intracellular Na NMR signal, differentiated by a shift reagent, 6 mM Dy(PPP)2, were obtained every 5 min, and T1 values were calculated. The T1 of the intracellular Na signal did not show any significant change either during hypoxia or upon reoxygenation, although the level of Nai increased about 50%.

Survey of cardiac rehabilitation centers in New York City.

Out-patient cardiac rehabilitation centers in New York City were surveyed in order to determine current practices. All 24 centers operating as of May, 1987 were sent questionnaires; 16 responded for a return rate of 67 percent. In general, practices of the centers were in accord with guidelines of the American Heart Association (AHA) and the American College of Sports Medicine.

Clinical zinc deficiency during long-term total enteral nutrition.

Zinc deficiency during long-term total parenteral nutrition has been well reported in the literature. However, there is limited information available on zinc deficiency occurring during total enteral nutrition. Two cases of clinical zinc deficiency in patients on long-term enteral feedings are presented.

Relationship of physicians' nonverbal communication skill to patient satisfaction, appointment noncompliance, and physician workload.

A field study of 28 residents in family practice was conducted. Physicians' self-reports of empathy, self-monitoring ability, and affective communication skill as well as their objectively measured nonverbal communication skills were examined as predictors of patient satisfaction, appointment noncompliance, and physician workload (schedule density). Physicians completed the Hogan Empathy Scale, Snyder Self-Monitoring Scale, Affective Communication Test, short form of the Profile of Nonverbal Sensitivity, and a nonverbal encoding task.

Effects of sex difference and dietary protein level on the binding of aflatoxin B1 to rat liver chromatin proteins in vivo.

The risk of aflatoxin-induced hepatocarcinoma is greater in males than in females and is similarly higher in animals fed 20% casein diets than in those fed 5%. In this study, groups of male and female F344 rats were fed either a 5 or 20% casein diet for 6 weeks. Two hr after a 1-mg/kg i.

Predicting patient satisfaction from physicians' nonverbal communication skills.

The relationship between physicians' nonverbal communication skills (their ability to communicate and to understand facial expression, body movement and voice tone cues to emotion) and their patients' satisfaction with medical care was examined in 2 studies. The research involved 71 residents in internal medicine and 462 of their ambulatory and hospitalized patients. Standardized, reliable and valid measures of nonverbal communication skills were administered to the physicians.

Patients' percentions of physicians' behavior: determinants of patient commitment to the therapeutic relationship.

This study examines the hypothesis that patients decide to remain committed to their primary care physicians (or to leave them and "doctor shop") primarily on the basis of the "socioemotional" aspects of the physicians' behavior. It was hypothesized that physicians' demonstrations of caring for patients as people and their openness of communication would be predictive of patient commitment to the therapeutic relationship, and that the physicians' competence and role performance (including thoroughness of information gathering) as perceived by patients would be less important. Interviews were conducted with 342 inpatients and ambulatory patients in a large urban community teaching hospital after a visit with one of 38 house officers in internal medicine.