Diet-induced obesity alters anabolic signalling in mice at the onset of skeletal muscle regeneration.

AIM: Obesity is classified as a metabolic disorder that is associated with delayed muscle regeneration following damage. For optimal skeletal muscle regeneration, inflammation along with extracellular matrix remodelling and muscle growth must be tightly regulated. Moreover, the regenerative process is dependent on the activation of myogenic regulatory factors (MRFs) for myoblast proliferation and differentiation. The purpose of this study was to determine how obesity alters inflammatory and protein synthetic signalling and MRF expression at the onset of muscle regeneration in mice. METHODS: Forty-eight male C57BL/6J mice (3 weeks old) were randomly assigned to either a high-fat diet (HFD, 60% fat) or a lean diet (10% fat) for 12 weeks. At 15 weeks, bupivacaine was injected into the tibialis anterior (TA) of the injured group (n = 5-8/group) and PBS was injected into the control (n = 5-6). The TA was excised 3 or 28 days after injection. RESULTS: We demonstrated impaired muscle regeneration in obese mice. The obese mice had reduced IL-6, MyoD and IGF-1 mRNA abundance compared to the lean mice (P < 0.05). Three days following muscle damage, TNF-α mRNA and protein levels of P-STAT3 and P-Akt were 14-fold, fourfold and fivefold greater in the lean mice respectively. However, there were no differences observed in the obese injured group compared to the uninjured group. Moreover, p70S6K1 was threefold greater in lean injured mice compared to uninjured but was reduced by 28% in the obese injured mice. CONCLUSION: Obese mice have impaired inflammatory and protein synthetic signalling that may negatively influence muscle regeneration.

Effects of pressure support ventilation and continuous positive airway pressure on diaphragm performance.

Many patients who are on mechanical ventilation are on ventilator modes called pressure support ventilation (PSV) and continuous positive airway pressure (CPAP) particularly when they are being weaned. As the diaphragm is responsible for approximately 75% of breathing, it is important to promote diaphragm shortening to optimize weaning from mechanical ventilation. The purpose of our 1998 quasi-experimental study was to explore the effects of PSV and CPVP on diaphragm shortening. An animal model was utilized using four Sprague-Dawley rats from the same litter purchased from Sasco (Kansas City, USA). Also measured in this study were intrathoracic pressure (DeltaITP), positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, central venous pressure (CVP) and mean arterial pressure (MAP). Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed. These results support that higher levels CPAP may hinder diaphragmatic function thus prolong mechanical ventilation. The purpose of this pilot study was to explore the effects of PSV and CPAP on diaphragm shortening. Also measured were DeltaITP, positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, CVP and MAP. Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed.

Use of the Critical Thinking Disposition Inventory in critical care orientation.

In the current health care environment it is imperative that orientation programs be effective and efficient in the preparation of nurses entering critical care nursing. Institutions strive to develop orientation programs that use the least amount of resources necessary to achieve the desired outcome. The desired outcome of the critical care orientation process is for nurses to use critical thinking skills to make sound clinical judgments based on scientific knowledge of critical care nursing. Identifying areas of strengths and deficits in critical thinking could prove beneficial in assisting educators to individualize nursing orientation programs using critical thinking skills in practice. The purpose of this article is to describe a method used to measure nurses' dispositions toward critical thinking and the application of the California Critical Thinking Disposition Inventory (CCTDI) in critical care orientation programs.

Making sense of a new nursing role: a phenomenological study of an organizational change.

Although health care organizational change is a constant phenomenon, little is understood as to how staff experience this change. Unsuccessful change efforts have suggested the possible important relationship between understanding staff's experience and improved results. The purpose of this phenomenological study was to describe what staff on a medical-surgical unit experience during the initial phase of the implementation of a nursing care coordinator position, a first step in a broad organizational change. A purposeful sample of 11 nursing and non-nursing staff, considered unit experts, were interviewed using broad, open-ended questions designed to solicit their experience. Additionally, observations and document abstraction were used to add depth and clarification to the interviews. Analysis of data was conducted using a combination of Giorgi's and Colaizzi's procedures. Contextual elements framing staff's experiences included introduction of a new role with no organizational history into an increasingly demanding environment that staff perceived as constantly changing. Major themes of "experiencing the effect" and "struggling to make sense" were revealed. These findings suggest that the introduction of a new role can create turmoil and job insecurity in the current health care environment. Recommendations to support staff's efforts to "make sense" are provided.

Effects of volume control, pressure control, and pressure-regulated volume control on cardiopulmonary parameters in a normal rat lung.

The purpose of this study was to investigate the differences in diaphragm shortening and cardiopulmonary parameters at varying tidal volumes during volume control (VC), pressure control (PC), and pressure-regulated volume control (PRVC). A miniaturized ultrasonic sensor attached to the inferior surface of the upper costal surface of the right hemidiaphragm of 16 Sprague-Dawley rats provided a direct assessment of diaphragm shortening. Within each control mode of mechanical ventilation, the tidal volume was increased from 3 to 12 ml in increments of 3 ml. There were no differences in cardiac output, mean arterial pressure, central venous pressure, peak inspiratory pressure, or end-tidal CO2 among the three modes of mechanical ventilation. At equivalent tidal volumes, diaphragm shortening was less during PRVC than during VC or PC. This finding suggests that differences in diaphragm shortening may be caused by shorter resting (end-expiratory) diaphragm muscle length. The cardiopulmonary data obtained in this study provide new information for clinicians to consider when using various modes of ventilation, particularly PRVC.

Total quality management and quality assurance: discussing the differences.

Total Quality Management and Continuous Quality Improvement have become the "buzz" phrase for the 1990s. Everyone seems to be jumping on the band wagon. But what is it, and is it right for your organization? We believe that Total Quality Management is superior to many Quality Assurance programs currently in use. There are, however, many considerations to take into account before implementing a Total Quality Management program. The purpose of this article is to explain the pros and cons of Total Quality Management and standard Quality Assurance programs and to compare and contrast these two approaches. This article focuses on barriers to successful implementation and presents several questions organizations can utilize in assessing readiness for a quality management program.