Effect of opacifiers on color stability of pigmented maxillofacial silicone A-2186 subjected to artificial aging

PURPOSE: This study was designed to determine the effect of opacifiers used at different ratios on the color stability of pigmented A-2186 silicone maxillofacial elastomers and to evaluate the color spectrophotometrically before and after artificial aging. MATERIALS AND METHODS: Sixty experimental groups of elastomers were made using various concentrations (5%, 10%, and 15%) of 4 opacifiers (Georgia kaolin powder neutral, kaolin powder calcined, Artskin white, and dry pigment titanium white) with 1 of 5 dry earth cosmetic pigment groups (no pigment [control], red, yellow ochre, burnt sienna, and a mixture of all pigments). Five specimens of each elastomer were tested, for a total of 300 specimens. All specimens were placed in an aging chamber and artificially aged by exposure to light, water spray, fluctuating temperatures, and humidity. CIE L*a*b* values were measured by spectrophotometer. The color differences (Delta E*) at various exposure energies (150, 300, and 450 kJ/m(2)) were subjected to 4-way analysis of variance with repeated measures (super ANOVA). Mean values were compared with Tukey-Kramer intervals calculated at the 0.05 significance level. RESULTS: The trained human eye can detect color changes (Delta E*) greater than 1.0. Adding all pigments to any of the kaolin groups did not protect silicone A-2186 from color degradation over time. Mixing red pigment in all groups at all times drastically increased DeltaE* values ranging from 0.1 to 1.3 up to 16.6 to 49.6. Yellow ochre had an effect only with 10% and 15% concentrations of kaolin powder calcined, increasing the value of Delta E* to greater than 1.0. Burnt sienna had an effect only with a 15% concentration of kaolin powder calcined, increasing the value of Delta E* at 300 and 450 kJ/m(2) to greater than 11.0. At the 5% concentration, kaolin powder calcined had the smallest color changes, followed by, in order, dry pigment titanium white, Artskin white, and Georgia kaolin. At the 10% concentration, Artskin white had the smallest color changes, followed by, in order, dry pigment titanium white, kaolin powder calcined, and Georgia kaolin. At the 15% concentration, Artskin white again had the smallest color changes, followed by, in order, dry pigment titanium white, Georgia kaolin, and the kaolin powder calcined. The smallest color changes in each kaolin group were at the 10% concentration for Artskin white, dry pigment titanium white, and kaolin powder calcined and at the 5% concentration for Georgia kaolin. CONCLUSIONS: Mixing dry earth cosmetic pigments with opacifiers did not protect silicone A-2186 from color degradation over time, especially in the case of red pigment. The group in which pigments were mixed with 10% Artskin white had the smallest color changes over time, followed by, in order, the groups in which pigments were mixed with 10% dry pigment titanium white, 10% kaolin powder calcined, and 5% Georgia kaolin. Red pigment had a significant effect on all opacifiers, especially Georgia kaolin and kaolin powder calcined. Yellow ochre and burnt sienna had an effect only on 15% kaolin powder calcined. Among all the pigment groups tested, yellow ochre remained the most color stable over time.     

Role of preoperative carbohydrate loading: a systematic review

INTRODUCTION

Surgical stress in the presence of fasting worsens the catabolic state, causes insulin resistance and may delay recovery. Carbohydrate rich drinks given preoperatively may ameliorate these deleterious effects. A systematic review was undertaken to analyse the effect of preoperative carbohydrate loading on insulin resistance, gastric emptying, gastric acidity, patient wellbeing, immunity and nutrition following surgery.

METHODS

All studies identified through PubMed until September 2011 were included. References were cross-checked to ensure capture of cited pertinent articles.

RESULTS

Overall, 17 randomised controlled trials with a total of 1,445 patients who met the inclusion criteria were identified. Preoperative carbohydrate drinks significantly improved insulin resistance and indices of patient comfort following surgery, especially hunger, thirst, malaise, anxiety and nausea. No definite conclusions could be made regarding preservation of muscle mass. Following ingestion of carbohydrate drinks, no adverse events such as apparent or proven aspiration during or after surgery were reported.

CONCLUSIONS

Administration of oral carbohydrate drinks before surgery is probably safe and may have a positive influence on a wide range of perioperative markers of clinical outcome. Further studies are required to determine its cost effectiveness.     

Trends in the Timing and Clinical Context of Maintenance Dialysis Initiation

Whether secular trends in eGFR at dialysis initiation reflect changes in clinical presentation over time is unknown. We reviewed the medical records of a random sample of patients who initiated maintenance dialysis in the Department of Veterans Affairs (VA) in fiscal years 2000–2009 (n=1691) to characterize trends in clinical presentation in relation to eGFR at initiation. Between fiscal years 2000–2004 and 2005–2009, mean eGFR at initiation increased from 9.8±5.8 to 11.0±5.5 ml/min per 1.73 m² (P<0.001), the percentage of patients with an eGFR of 10–15 ml/min per 1.73 m² increased from 23.4% to 29.9% (P=0.002), and the percentage of patients with an eGFR>15 ml/min per 1.73 m² increased from 12.1% to 16.3% (P=0.01). The proportion of patients who were acutely ill at the time of initiation and the proportion of patients for whom the decision to initiate dialysis was based only on level of kidney function did not change over time. Frequencies of documented clinical signs and/or symptoms were similar during both time periods. The adjusted odds of initiating dialysis at an eGFR of 10–15 or >15 ml/min per 1.73 m² (versus <10 ml/min per 1.73 m²) during the later versus earlier time period were 1.43 (95% confidence interval [95% CI], 1.13 to 1.81) and 1.46 (95% CI, 1.09 to 1.97), respectively. In conclusion, trends in eGFR at dialysis initiation at VA medical centers do not seem to reflect changes in the clinical context in which dialysis is initiated.     

Cellular resolution anatomical and molecular atlases for prenatal human brains

Increasing interest in studies of prenatal human brain development, particularly using new single-cell genomics and anatomical technologies to create cell atlases, creates a strong need for accurate and detailed anatomical reference atlases. In this study, we present two cellular-resolution digital anatomical atlases for prenatal human brain at postconceptional weeks (PCW) 15 and 21. Both atlases were annotated on sequential Nissl-stained sections covering brain-wide structures on the basis of combined analysis of cytoarchitecture, acetylcholinesterase staining, and an extensive marker gene expression dataset. This high information content dataset allowed reliable and accurate demarcation of developing cortical and subcortical structures and their subdivisions. Furthermore, using the anatomical atlases as a guide, spatial expression of 37 and 5 genes from the brains, respectively, at PCW 15 and 21 was annotated, illustrating reliable marker genes for many developing brain structures. Finally, the present study uncovered several novel developmental features, such as the lack of an outer subventricular zone in the hippocampal formation and entorhinal cortex, and the apparent extension of both cortical (excitatory) and subcortical (inhibitory) progenitors into the prenatal olfactory bulb. These comprehensive atlases provide useful tools for visualization, segmentation, targeting, imaging, and interpretation of brain structures of prenatal human brain, and for guiding and interpreting the next generation of cell census and connectome studies.     

Rehabilitation content and clinical stroke subtype: a small observational study

Purpose. The Oxford classification categorises stroke according to clinical features. Differences in terms of mortality, institutionalisation, recurrence and achievement of mobility milestones have been demonstrated across clinical subtypes. This study aimed to describe differences in content of occupational therapy and physiotherapy activities, according to clinical stroke subtype.

Method. This retrospective study forms part of a larger research project (n = 419). Ten patients from each of five clinical subtypes were randomly selected and therapy content was recoded from the medical notes using a coding tool.

Results. The content of therapy sessions varied across subtypes, for both occupational therapy and physiotherapy sessions. Kruskal–Wallis analysis showed significant difference between subtypes for passive movements and transfers (p < 0.05) and standing balance, walking and stairs (p < 0.01). Similarly, significant differences between subtypes were seen in personal activities of daily living and the assessment or treatment of mood/cognitive problems (p < 0.05).

Conclusions. The results show differences in the content of occupational and physiotherapy sessions across clinical stroke subtypes. Findings from this study could be used to help workforce planning and inform future studies with a larger sample.     

Oral and dental management of the cancer patient: prevention and treatment of complications

Aggressive cancer therapy places patients at greater risk for oral complications and treatment-related consequences. Unfortunately, prevention and/or treatment of such oral sequelae has become an often overlooked priority of the treatment team. We describe a philosophy of management of the cancer patient that specifically emphasizes the prevention and treatment of oral complications associated with cancer therapy. These concepts and principles are based on treatment protocols and ongoing clinical research at The University of Texas M. D. Anderson Cancer Center in Houston, Texas.     

Two Minutes of Sprint-Interval Exercise Elicits 24-hr Oxygen Consumption Similar to That of 30 min of Continuous Endurance Exercise

Six weeks (3 times/wk) of sprint-interval training (SIT) or continuous endurance training (CET) promote body-fat losses despite a substantially lower training volume with SIT. In an attempt to explain these findings, the authors quantified VO2 during and after (24 h) sprint-interval exercise (SIE; 2 min exercise) vs. continuous endurance exercise (CEE; 30 min exercise). VO2 was measured in male students (n = 8) 8 times over 24 hr under 3 treatments (SIE, CEE, and control [CTRL, no exercise]). Diet was controlled. VO2 was 150% greater (p < .01) during CEE vs. SIE (87.6 ± 13.1 vs. 35.1 ± 4.4 L O2; M ± SD). The observed small difference between average exercise heart rates with CEE (157 ± 10 beats/min) and SIE (149 ± 6 beats/min) approached significance (p = .06), as did the difference in peak heart rates during CEE (166 ± 10 beats/min) and SIE (173 ± 6 beats/min; p = .14). Total O2 consumed over 8 hr with CEE (263.3 ± 30.2 L) was greater (p < .01) than both SIE (224.2 ± 15.3 L; p < .001) and CTRL (163.5 ± 16.1 L; p < .001). Total O2 with SIE was also increased over CTRL (p < .001). At 24 hr, both exercise treatments were increased (p < .001) vs. CTRL (CEE = 500.2 ± 49.2; SIE = 498.0 ± 29.4; CTRL = 400.2 ± 44.6), but there was no difference between CEE and SIE (p = .99). Despite large differences in exercise VO2, the protracted effects of SIE result in a similar total VO2 over 24 hr vs. CEE, indicating that the significant body-fat losses observed previously with SIT are partially due to increases in metabolism postexercise.