Heated humidified high-flow nasal cannula versus low-flow nasal cannula as weaning mode from nasal CPAP in infants ≤28 weeks of gestation

Despite the paucity of evidence, the practice of weaning nasal continuous positive airway pressure (NCPAP) is widespread. However, the most clinically effective non-invasive ventilatory support strategy remains to be determined. We compared the outcome of very premature infants with respiratory distress syndrome treated with a combination of NCPAP and heated humidified high-flow nasal cannula (HHFNC) versus NCPAP and low-flow nasal cannula (LFNC). Between 2004 and 2008, patients ≤28 weeks of gestation and <1,250 g of birth weight were treated with NCPAP + HHFNC or NCPAP + LFNC. Their respiratory and non-respiratory outcome including cost-effectiveness was compared after matching for antenatal steroid doses, mode of delivery, birth plurality, gestational age, birth weight, gender, surfactant doses, length of mechanical ventilation and clinical risk index for babies-II (CRIB-II) score. Thirty-nine infants received HHFNC + NCPAP, and 40 received NCPAP + LFNC. Median gestational age and birth weight were 27 weeks and 930 g and 27 weeks and 980 g, respectively. The total number of NCPAP days was significantly reduced by 50 % in the HHFNC group. Thirteen percent of the patients on NCPAP suffered from nasal bridge lesions compared to none on HHFNC. Respiratory and non-respiratory outcome was not significantly different otherwise. Combination of NCPAP and HHFNC reduced costs by 33 %. Conclusions: HHFNC shortens NCPAP time without increasing overall length of non-invasive respiratory support in very preterm infants. Unlike NCPAP, HHFNC does not seem to increase the risk of nasal trauma and appears to improve cost-effectiveness whilst producing otherwise equal respiratory and non-respiratory outcomes.     

A Retrospective Evaluation of the Survival Rates of Splinted and Non‐Splinted Short Dental Implants in Posterior Partially Edentulous Jaws

Background: The aim of the present study is to evaluate the survival rate and bone loss around short implants (≤10 mm) supporting splinted or non‐splinted posterior prostheses during a follow‐up period of 3 to 16 years. Methods: A total of 453 implants from 198 patients was divided into splinted or non‐splinted groups. Implant survival rate was calculated for each group, and potential risk was represented as odds ratio (OR). The final linear distance from implant platform level to the first bone‐to‐implant contact was compared to this same reference just after loading by digital periapical radiographs to determine the marginal bone loss (BL). Results: The splinted group comprised 219 implants in 86 patients, whereas the non‐splinted group included 234 implants from 112 patients. The mean follow‐up period was 9.7 ± 3.7 years. Although different success rates were found for splinted (97.7%) and non‐splinted (93.2%) groups, they exhibited similar BL (1.22 ± 0.95 mm and 1.27 ± 1.15 mm, respectively). The success of splinted implants was associated with no other variable, whereas non‐splinted implants exhibited higher risk of failure when placed in men (OR = 3.2) and when implants shorter than 10 mm were used (OR = 3.6 and 4.1 for 8.5 mm and 7 mm, respectively). Regardless of group, 71.4% of the unsuccessful implants failed before the end of the first year after loading. Conclusion: Non‐splinted posterior short implants had a somewhat lower success rate than splinted short implants, and the failure rate in non‐splinted short implants appeared to be greater in males as well as in implants ≤10 mm.     

Concentration-dependent Effect of Sodium Hypochlorite on Stem Cells of Apical Papilla Survival and Differentiation

Introduction

Intracanal disinfection is a crucial step in regenerative endodontic procedures. Most published cases suggest the use of sodium hypochlorite (NaOCl) as the primary irrigant. However, the effect of clinically used concentrations of NaOCl on the survival and differentiation of stem cells is largely unknown. In this study, we tested the effect of various concentrations of NaOCl on the stem cells of the apical papilla (SCAPs) survival and dentin sialophosphoprotein (DSPP) expression.

Methods

Standardized root canals were created in extracted human teeth and irrigated with NaOCl (0.5%, 1.5%, 3%, or 6%) followed by 17% EDTA or sterile saline. SCAPs in a hyaluronic acid–based scaffold were seeded into the canals and cultured for 7 days. Next, viable cells were quantified using a luminescence assay, and DSPP expression was evaluated using quantitative real-time polymerase chain reaction.

Results

There was a significant reduction in survival and DSPP expression in the group treated with 6% NaOCl compared with the untreated control group. Comparable survival was observed in the groups treated with the lower concentrations of NaOCl, but greater DSPP expression was observed in the 1.5% NaOCl group. In addition, 17% EDTA resulted in increased survival and DSPP expression partially reversing the deleterious effects of NaOCl.

Conclusions

Collectively, the results suggest that dentin conditioning with high concentrations of NaOCl has a profound negative effect on the survival and differentiation of SCAPs. However, this effect can be prevented with the use of 1.5% NaOCl followed by 17% EDTA. The inclusion of this irrigation regimen might be beneficial in regenerative endodontic procedures.     

Lack of vitamin D receptor causes stress-induced premature senescence in vascular smooth muscle cells through enhanced local angiotensin-II signals

Objectives

The inhibition of the renal renin-angiotensin system by the active form of vitamin D contributes to the cardiovascular health benefits of a normal vitamin D status. Local production of angiotensin-II in the vascular wall is a potent mediator of oxidative stress, prompting premature senescence. Herein, our objective was to examine the impact of defective vitamin D signalling on local angiotensin-II levels and arterial health.

Methods

Primary cultures of aortic vascular smooth muscle cells (VSMC) from wild-type and vitamin D receptor-knockout (VDRKO) mice were used for the assessment of cell growth, angiotensin-II and superoxide anion production and expression levels of cathepsin D, angiotensin-II type 1 receptor and p57^Kip2. The in vitro findings were confirmed histologically in aortas from wild-type and VDRKO mice.

Results

VSMC from VDRKO mice produced more angiotensin-II in culture, and elicited higher levels of cathepsin D, an enzyme with renin-like activity, and angiotensin-II type 1 receptor, than wild-type mice. Accordingly, VDRKO VSMC showed higher intracellular superoxide anion production, which could be suppressed by cathepsin D, angiotensin-II type 1 receptor or NADPH oxidase antagonists. VDRKO cells presented higher levels of p57^Kip2, impaired proliferation and premature senescence, all of them blunted upon inhibition of angiotensin-II signalling. In vivo studies confirmed higher levels of cathepsin D, angiotensin-II type 1 receptor and p57^Kip2 in aortas from VDRKO mice.

Conclusion

The beneficial effects of active vitamin D in vascular health could be a result of the attenuation of local production of angiotensin-II and downstream free radicals, thus preventing the premature senescence of VSMC.     

Static jaw collimation settings to minimize radiation dose to normal brain tissue during stereotactic radiosurgery

At the University of Arkansas for Medical Sciences (UAMS) intracranial stereotactic radiosurgery (SRS) is performed by using a linear accelerator with an add-on micromultileaf collimator (mMLC). In our clinical setting, static jaws are automatically adapted to the furthest edge of the mMLC-defined segments with 2-mm (X jaw) and 5-mm (Y jaw) margin and the same jaw values are applied for all beam angles in the treatment planning system. This additional field gap between the static jaws and the mMLC allows additional radiation dose to normal brain tissue. Because a radiosurgery procedure consists of a single high dose to the planning target volume (PTV), reduction of unnecessary dose to normal brain tissue near the PTV is important, particularly for pediatric patients whose brains are still developing or when a critical organ, such as the optic chiasm, is near the PTV. The purpose of this study was to minimize dose to normal brain tissue by allowing minimal static jaw margin around the mMLC-defined fields and different static jaw values for each beam angle or arc. Dose output factors were measured with various static jaw margins and the results were compared with calculated doses in the treatment planning system. Ten patient plans were randomly selected and recalculated with zero static jaw margins without changing other parameters. Changes of PTV coverage, mean dose to predefined normal brain tissue volume adjacent to PTV, and monitor units were compared. It was found that the dose output percentage difference varied from 4.9–1.3% for the maximum static jaw opening vs. static jaw with zero margins. The mean dose to normal brain tissue at risk adjacent to the PTV was reduced by an average of 1.9%, with negligible PTV coverage loss. This dose reduction strategy may be meaningful in terms of late effects of radiation, particularly in pediatric patients. This study generated clinical knowledge and tools to consistently minimize dose to normal brain tissue.     

Simvastatin decreases nitric oxide overproduction and reverts the impaired vascular responsiveness induced by endotoxic shock in rats

Lipopolysaccharides (LPS) can be used to induce experimental endotoxic shock, which is characterized by a significant decrease in mean arterial pressure (MAP) and a decreased vasoconstrictor response that have been attributed to excessive nitric oxide production. Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase), in addition to lowering serum cholesterol levels, exert many pleiotropic effects, including anti-inflammatory action. In the present study, we investigated the effect of simvastatin, an HMG-CoA reductase inhibitor, on the production of nitric oxide and the cardiovascular response to LPS. Male Wistar rats were pretreated with different doses of simvastatin (10, 20, 40, and 80 mg/kg, i.p.) or saline 20 min before i.v. injection of LPS (1.5 mg/kg) or saline (control). MAP was continuously recorded and nitrate plasma concentration was determined during the 6-h experimental session at 1-h intervals. The pressor response to phenylephrine (1 microg/kg) was evaluated before and 6 h after LPS administration. In the LPS-treated group, there was a time-dependent increase in nitrate plasma concentration (P<0.001), and this response was decreased in simvastatin pretreated rats (P<0.001). We also observed that LPS decreased the pressor response to phenylephrine (P<0.001), an effect that was reverted by simvastatin pretreatment (P<0.05). However, simvastatin did not modify the decrease of MAP induced by LPS. We concluded that simvastatin decreases nitrate plasma concentration in response to LPS and recovers vascular responsiveness during an experimental endotoxic shock. These data suggest the potential use of HMG-CoA reductase inhibitors as a coadjuvant in the treatment of septic shock.     

Implementing an i.v. iron maintenance regimen protocol in a hemodialysis practice.

Iron-deficiency anemia is commonly encountered in patients with end-stage renal disease (ESRD) requiring chronic hemodialysis and can occur as a result of blood loss from frequent laboratory tests, blood retention in the dialysis tubing and dialyzer, gastrointestinal (GI) bleeding, repeated access surgery, poor oral iron intake and/or absorption, and low protein diets (Sakiewicz, 1998; Eschbach, 1999). Further compounding the deficiency is the use of recombinant human erythropoietin (EPO), which stimulates erythropoiesis to abnormally high levels and leads to functional iron deficiency in up to 90% of patients (Macdougall, 1995; Sunder-Plassmann, 1997).     

Preventing shoulder pain after cardiac rhythm management device implantation: a randomized, controlled study

Introduction: Shoulder pain and disability ipsilateral to the implant site is a common complication of cardiac rhythm device implantation, yet very little has been published about this morbidity. We designed a study to assess the potential benefit of a simple exercise protocol in preventing shoulder pain postoperatively. Methods and Results: Patients undergoing subcutaneous device implantation were randomized to one of two groups. The control group received standard instructions, whereas the exercise group was instructed on specific exercises aimed at strengthening or stretching the shoulder girdle, to be completed 3 days per week. Groups were postoperatively monitored for the development of shoulder discomfort and shoulder impingement by using physical examination and disability questionnaires. At 1 month, seven of 21 control patients reported developing shoulder pain or discomfort compared to one of 23 in the exercise group (P = 0.02). At 6 months, four of 23 control patients still reported worsening shoulder symptoms, compared to none in the exercise group (P = 0.11). In the control group, five of 19 patients developed a positive impingement test at 1 month, versus none in the exercise group (P = 0.01). Scores for the questionnaires designed to assess shoulder pain and dysfunction were worse in the control group. There were no activity‐related complications in either group. Conclusion: Shoulder pain and disability occurs often following cardiac rhythm management device implantation. A simple exercise program aimed at strengthening the shoulder girdle is effective at preventing this complication. (PACE 2011; 672–678)     

Nuclear magnetic resonance studies of lithium transport in erythrocyte suspensions of hypertensives

We have applied a nuclear magnetic resonance (NMR) method, based on the 7Li nucleus, to discriminate between intracellular and extracellular lithium ions (Li+) in red blood cell (RBC) suspensions. The NMR method was compared with atomic absorption, a technique that requires physical separation of intra- and extracellular Li+ prior to chemical analysis. The rates and rate constants of RBC Na(+)-Li+ countertransport measured by the 7Li NMR method correlated significantly with the measurements made by atomic absorption for both the hypertensive (r = 0.964) and control (r = 0.961) groups. The rates of RBC Na(+)-Li+ countertransport measured by NMR were significantly higher for hypertensive patients than for normotensive controls. The fact that the NMR method does not require cell membrane lysis, and its potential to reveal structural and mechanistic information on Li+ binding and transport in cellular systems, makes it promising for understanding the basis of Li+ transport variations in RBCs, and possibly other tissues, from hypertensive patients.