Expression of mRNA transcripts for ATP-sensitive potassium channels in human myometrium.

The molecular mechanisms regulating human uterine quiescence and parturition are poorly understood. Potassium channels are central to regulation of cell membrane potential and contractility of smooth muscle. The aim of this study was to examine the expression of ATP-sensitive potassium channel (K(ATP) channel) subunits in human myometrium, and to investigate for possible differential expression of these subunits in myometrium obtained from three different functional states: (i) non-pregnant (NP); (ii) late pregnant not in labour (PNL); and (iii) late pregnant in labour (PL). RT-PCR detected the presence of mRNA for four subunits of K(ATP) channels (Kir6.1, Kir6.2, SUR1 and SUR2B) in the three tissue types. Quantitative analysis of these subunits was achieved with real-time RT-PCR using Lightcycler(TM) technology. This analysis showed that there were significantly higher levels of Kir6.1 and SUR2B transcripts in NP myometrium compared with those measured in myometrium obtained during pregnancy (P < 0.001). Lower levels of Kir6.2 and SUR1 mRNA expression were found, although higher transcript levels in NP myometrium (P < 0.05) were still observed. Our results indicate that the major K(ATP) channel expressed in human myometrium is composed of Kir6.1 and SUR2B, and that down-regulation of this channel may facilitate myometrial function during late pregnancy.

A role for HNF-3 in the regulation of the HNF-1 gene of the Atlantic salmon.

Hepatocyte nuclear factors -1 (HNF-1) and -3 (HNF-3) are hepatocyte-enriched transcription factors that are central to the establishment and maintenance of the liver phenotype in vertebrates. In the present study we demonstrate that, in the Atlantic salmon, asHNF-3 regulates the expression of the gene for asHNF-1. Multiple putative binding sites for asHNF-3 were identified within the 5' flanking region of the HNF-1 gene using a computer-based algorithm, and these were confirmed to be functional by electrophoretic mobility shift assays. In transient transfection assays it was shown that co-expression of asHNF-3 leads to a decrease in the promoter activity of the 5' flanking region of the asHNF-1 gene.

Recreational scuba divers' aversion to low-frequency underwater sound.

Increasing use of active low-frequency sonar by submarines and ships raises the risk of accidental exposure of recreational divers to low-frequency underwater sound (LFS). This study aimed to characterize the subjective responses of recreational scuba divers to LFS to ascertain the extent to which LFS may impact their enjoyment, comfort, or time spent underwater. Seventeen male and nine female recreational scuba divers participated. Diving was conducted in an acoustically transparent tank located within a larger anechoic pool. Subjects wore scuba gear and were positioned I m below the surface in a prone position. The sound transducer was located 4 m directly below the diver's head. Sound exposures consisted of three signal types (pure tone, 30 Hz hyperbolic sweep up, and 30 Hz hyperbolic sweep down) each presented at six center frequencies from 100 to 500 Hz and six sound pressure levels(SPL) ranging from 130 to 157 dB re 1 microPa. The duration of each sound exposure was 7 s. Subjects responded via an underwater console to rate aversion to LFS on a category-ratio scale, and to indicate the presence or absence of vibration of any body part. Aversion to LFS and the percent incidence of vibration increased as the SPL increased. The percent incidence of vibration decreased linearly with increasing frequency. At the highest SPL the probability that an aversion rating would exceed Very Severe (7 on the category-ratio scale) was predicted to be 19%. There was no significant difference in aversion among signal types. The 100 Hz frequency was the most aversive frequency (P < 0.05). A plot of aversion vs. frequency showed a U-shaped function with minimum aversion at 250 Hz. In conclusion, diver aversion to LFS is dependent upon SPL and center frequency. The highest aversion rating was given for 100 Hz, this frequency corresponded with the greatest probability of detecting vibration. Factors other than vibration seem to account for aversion to the highest frequencies. Our data suggest that LFS exposures up to 145 dB re 1 microPa at frequencies between 100 and 500 Hz will have minimal impact on the recreational diver.

Cysteine metabolism and whole blood glutathione synthesis in septic pediatric patients.

OBJECTIVE: To investigate whole body in vivo cysteine kinetics and its relationship to whole blood glutathione (GSH) synthesis rates in septic, critically ill pediatric patients and controls. DESIGN: Prospective cohort study. SETTING: Multidisciplinary intensive care unit and pediatric inpatient units at a children's hospital. PATIENTS: Ten septic pediatric patients and ten controls (children admitted to the hospital for elective surgery). INTERVENTIONS: Septic patients (age, 31 months to 17 yrs) and controls (age, 24 months to 21 yrs) received a 6-hr primed, constant, intravenous tracer infusion of l-[1-13C]cysteine. Blood samples were obtained to determine isotopic enrichment of plasma cysteine and whole blood [1-13C]cysteinyl-glutathione by gas-chromatography mass spectrometric techniques. The plasma flux and oxidation rate of cysteine and the fractional and absolute synthesis rates of GSH were determined. Septic patients received variable protein and energy intake, as per routine clinical management, and controls were studied in the early postabsorptive state. MEASUREMENTS AND MAIN RESULTS: Plasma cysteine fluxes were increased in the septic patients when compared with the controls (68.2 +/- 17.5 [sd] vs. 48.7 +/- 8.8 micromol x kg(-1) x hr(-1); p <.01), and the fraction of plasma cysteine flux associated with oxidative disposal was similar among the groups. The absolute rates of GSH synthesis in whole blood were decreased (p <.01) in the septic patients (368 +/- 156 vs. 909 +/- 272 micromol x L(-1) x day(-1)). The concentration of whole blood GSH also was decreased in the septic group (665.4 +/- 194 vs. 1059 +/- 334 microM; p <.01) CONCLUSIONS: Whole blood glutathione synthesis rates are decreased, by about 60%, in critically ill septic children receiving limited nutritional support. Plasma cysteine fluxes and concentration of cysteine were increased in the septic patients, suggesting a hypermetabolic state with increased protein breakdown. The mechanisms whereby GSH synthesis rates are decreased in these patients are probably multifactorial, presumably involving an inflammatory response in the presence of limited nutritional support. The role of nutritional modulation and the use of cysteine prodrugs in maintaining GSH concentration and synthesis remain to be established.

Single-arm double-mode double-order planar waveguide interferometric sensor.

A sensor is described for which interference measurements of the phase delay between two propagating modes of different orders in a slab thin-film waveguide are used as the sensing technique. The basic building block of the sensor is a polymer film doped with an indicator dye such as Bromocresol Purple. The modes of two orders such as TM(0) and TM(1) are simultaneously excited in the light-guiding film with a focusing optics and a prism coupler. The modes are decoupled from the film and recombined to produce an interference pattern in the face of an output optical fiber. The sensitivity of the sensor to the ambient temperature change is 1.5 degrees C, and the sensitivity to NH(3) is 200 parts in 10(6) for one full oscillation of the signal.

The effects of early and repeated prone positioning in pediatric patients with acute lung injury.

STUDY OBJECTIVE: To describe the physiologic changes and to evaluate the safety of placing pediatric patients with acute lung injury (ALI) prone for 20 h/d during the acute phase of their illness. DESIGN: Single-center prospective case series. SETTING: Tertiary-level pediatric ICU. PATIENTS: Consecutive patients with bilateral pulmonary parenchymal disease requiring intubation and mechanical ventilation with a PaO(2)/fraction of inspired oxygen (FIO(2)) ratio /= 20 mm Hg in PaO(2)/FIO(2) ratio or a decrease of >/= 10% in oxygenation index when shifted from a supine to a prone position during the study period. During the 107 patient-days and 214 positioning cycles, no critical incidents occurred. Furthermore, no patient experienced a persistent decrease in oxygen saturation as measured by pulse oximetry (SpO(2)) of > 10% from values obtained when in the supine position, failed to keep their SpO(2) at > 85%, or experienced an increased respiratory rate of > 40 breaths/min when prone. Using the COMFORT score, patients were objectively rated to be equally comfortable in both the supine and prone positions. Patients also were able to resume spontaneous ventilation and to progress toward endotracheal extubation while in the prone position. Iatrogenic injury associated with prolonged prone positioning included stage II pressure ulcers in six patients (24%). CONCLUSIONS: The pediatric patients in this series demonstrated improvements in oxygenation without serious iatrogenic injury after prone positioning. This study provides a foundation for a prospective randomized study investigating the effect of early and repeated prone positioning on clinical outcomes in pediatric patients with ALI.

Effect of adaptive motion-artifact reduction on QRS detection.

Motion artifact resulting from electrode and patient movement is a significant source of noise in ECG, EEG, EMG, and impedance pneumography recording. Noise resulting from motion is particularly troublesome in ambulatory ECG recordings, such as those made during Holter monitoring or stress tests, because the bandwidth of the motion artifact overlaps with the ECG signal bandwidth. The authors investigated the effect of an adaptive motion-artifact removal algorithm on the performance of a standard QRS detector. They made four ECG recordings on each of the three subjects while manually generating artifact. Adaptive noise removal was applied to the ECG signal using a skin-stretch signal as the noise reference. Adaptive noise removal reduced the number of false QRS detections in the records from 380 to 104, for an average reduction in false detections of 72.6%. False-detection reductions for individual records ranged from 12% to 93%.

Prone positioning of patients with acute respiratory distress syndrome: a systematic review.

A computerized bibliographic search of published research and a citation review of English-language publications about prone positioning of patients with acute respiratory distress syndrome were done. Information on prone positioning related to technique, patients' responses, complications, and recommendations to prevent complications was extracted. In the 20 pertinent clinical studies found, 297 patients (mean age, 39 years) with acute respiratory failure were positioned prone. Timing from the onset of respiratory failure to when the patient was first positioned prone varied, as did the frequency of prone positioning. Patients spent from 30 minutes to 42 hours prone. In 47% of the studies in which abdominal position was noted, chest and pelvic cushions were used to allow the abdomen to protrude while the patient was prone. Improved oxygenation within 2 hours was reported in 69% of patients, and the improvements were cumulative and persistent. Aside from early intervention, factors predictive of patients' responses were inconsistent, and patients' initial responses were not predictive of subsequent responses. Iatrogenic critical events were rare. Dependent edema of the face was prevalent. Pressure ulcers were reported in studies with longer periods of prone positioning. The most serious complication, corneal abrasion requiring corneal transplantation, was reported in one patient. Clinical knowledge about prone positioning is limited. Phase 1 studies focusing on how to safely turn and care for critically ill patients positioned prone for prolonged periods are needed.

Weaning from mechanical ventilation: patterns in young children recovering from acute hypoxemic respiratory failure.

OBJECTIVE: The purpose of the study was to describe the patterns of weaning from mechanical ventilation in young children recovering from acute hypoxemic respiratory failure. METHODS: Decision-making rules on progressive weaning were developed and applied to existing data on 82 patients 2 weeks to 6 years old in the Pediatric Acute Respiratory Distress Syndrome Data Set. RESULTS: Three patterns of weaning progress were detected: sprint, consistent, and inconsistent. Length of ventilation and weaning progressively increased from the sprint, to the consistent, to the inconsistent subset. Patients in the inconsistent subset were most likely to have a systemic (sepsis or shock) trigger of acute respiratory distress syndrome and to be rated as having at least moderate disability at discharge. Hypothesis-generating univariate and then multivariate logistic regression analyses indicated that patients who experienced more days of mechanical ventilation before the start of weaning and who had a higher oxygenation index during the weaning process were most likely to have an inconsistent pattern of weaning. CONCLUSION: Patterns of weaning are discernible in a population of young children and indicate a subset at risk for inconsistent weaning. Knowing the patterns of weaning may help clinicians anticipate, perhaps plot, and then modulate a patient's weaning trajectory.

Nutrition and shock in pediatric patients.

Critically ill patients, including those in shock, often present with significant metabolic derangement in protein and energy metabolism characterized by: increased protein breakdown which is not suppressed by protein or energy intake; reprioritization of protein synthesis with increased synthesis of acute-phase proteins; decreased synthesis of structural proteins; and high protein turnover. In addition, there is also glucose and lipid intolerance. Adequate nutritional and metabolic support of the critically ill child under these conditions is a challenging endeavor. Traditionally, critically ill children have received nutritional requirements based on those of healthy children despite the fact that the critically ill population is physiologically and metabolically different. Furthermore, nutritional requirements in healthy children are largely based on limited data. With emerging knowledge of non-nutritional functions of nutrients, adequacy of nutritional support and requirements will eventually depend on the goals to be achieved: nutritional, physiologic, and/or pharmacologic.

Patient-nurse synergy: optimizing patients' outcomes.

Given the current demands of the healthcare environment, a clear sense of the unique contributions of nursing to patients' outcomes is critical. This paper articulates a model that describes nursing practice on the basis of the needs and characteristics of patients. The model was developed by the American Association of Critical-Care Nurses Certification Corporation to link certified practice to patients' outcomes. The fundamental premise of this model, known as the Synergy Model, is that patients' characteristics drive nurses' competencies. When patients' characteristics and nurses' competencies match and synergize, outcomes for the patient are optimal. This paper presents the major tenets of the Synergy Model: patients' characteristics of concern to nurses, nurses' competencies important to patients, and patients' outcomes that result when patients' characteristics and nurses' competencies are mutually enhancing. By creating safe passage for patients, nurses make a significant contribution to the quality of patients' care, containment of costs, and patients' outcomes. Although the Synergy Model will be used as a blueprint for the certification of acute and critical care nurses, it is conceptually relevant to the entire profession. Dissemination of this model may help situate nursing within the current healthcare environment and facilitate intradisciplinary dialogue.

Optical Studies of Nd-doped benzil, a potential luminescent and laser material.

Neodymium-doped benzil crystals have been synthesized and characterized for their absorption, emission, and kinetics properties. From Judd-Ofelt analysis, the radiative decay time of Nd emission (peaking at 1055 nm) is estimated to be equal to 441 mus. The experimental Nd lifetime (under Ar+ laser excitation) is equal to 19 mus. The broad emission band centered at approximately 700 nm (tau(decay) approximately 15 ns) and the Raman scattering with characteristic frequency shift of 1600 cm(-1) have been observed at excitation of benzil with 532-nm Q-switched laser pulses. We show that rare-earth-doped benzil can be considered as a potential candidate for luminescent and solid-state laser material.

Mutuality--an expression of nursing presence.

Nursing exists in the details of relationships. One crucial element of therapeutic nurse-patient/parent relationships is the attribute of mutuality. Mutuality not only embodies the philosophy of family-centered-care, it acknowledges and supports the evolution of parents and nurses toward greater competency in their role. Using concept analysis, this article explores the phenomenon of mutuality. The desired outcome is to provide a theoretical and operational definition of mutuality that will help guide practice and direct future research in the area of therapeutic nurse-parent relationships.

Ultrasound cardioscopy: embarking on a new journey.

OBJECTIVE: To present the results of investigation of a new application of invasive ultrasonography-ultrasound cardioscopy, a procedure in which a self-contained ultrasound device is capable not only of producing an under-blood field of view but also of delivering diagnostic and therapeutic tools. DESIGN: Twenty adult mongrel dogs were studied with the ultrasound cardioscopy device during experimental catheter ablation procedures. MATERIAL AND METHODS: A rigid prototype probe, 34 cm long and 8 mm in diameter with a 7-MHz side-viewing transducer at the tip and an 8-F diameter tool delivery port, was introduced through the right external jugular vein into the right heart chambers. Remote and device-directed ablation procedures were monitored. Subsequently, the canine hearts were excised and examined. RESULTS: The self-contained cardioscopy device with a contained ablation catheter could both direct and visualize a specified ablation injury. Under-blood observation of the details of the ablation procedure was possible. Although a learning curve existed for appropriate manipulation of the device, inspection of the excised hearts showed that the size of the injury was accurately predicted with use of ultrasound cardioscopy. CONCLUSION: Ultrasound cardioscopy is a promising means of performing precise under-blood diagnostic and therapeutic maneuvers.

Skin integrity in the pediatric population: preventing and managing pressure ulcers.

PURPOSE: To summarize clinical and empirical knowledge about pressure ulcers in infants and children and to describe an approach developed at Children's Hospital, Boston, to prevent and manage pressure ulcers. POPULATION: Acutely ill children with potential or actual alteration in skin integrity due to pressure ulcers. CONCLUSIONS: The three-pronged approach for pressure ulcer prevention and management developed by the Skin Care Task Force at the Children's Hospital, Boston, decreases unnecessary variation in practice surrounding the prevention and care of pressure ulcers in acutely ill children. PRACTICE IMPLICATIONS: The Skin Care Task Force recommends use of Braden Q for pediatric risk assessment, a skin care algorithm for prevention of pressure ulcers, and a pressure ulcer algorithm for staging and managing pressure ulcers.

Providing comfort to critically ill pediatric patients: isoflurane.

Isoflurane is a fluorinated ether used primarily as an inhalation anesthetic. Rapid titratable effects, limited metabolism, and a reliable mode of administration make isoflurane an appealing alternative to the use of intravenous sedatives and narcotics in critically ill patients requiring prolonged mechanical ventilation. This article, in reviewing this novel approach to management of patient discomfort, focuses on nursing practice issues and provides a critical analysis of isoflurane use in the intensive care unit.

Care of the child supported on high frequency oscillatory ventilation.

High frequency oscillatory ventilation is a new mode of ventilatory support of acute respiratory failure in the pediatric population. Delineating the nursing care required of this fragile group of infants and children is challenging, because there is a paucity of published data and national clinical experience. The author reviews a management plan that was used to guide the care of over 40 patients, ranging in age from 1 months to 24 years, with acute respiratory failure supported on high frequency oscillatory ventilation. In total, seven patient-care problems and associated interventions are delineated.