Preoperative stratification of pancreas-related morbidity after the Whipple procedure

Morbidity and mortality after pancreatoduodenectomy are greatly related to dehiscence of pancreatojejunostomy. We have analyzed risk factors of significance for and prediction of pancreas-related morbidity. We have retrospectively analyzed 122 patients. The relationship of fibrosis of pancreas, exocrine function, and diameter of pancreatic duct to pancreas-related morbidity was evaluated. Computer-aided morphometric analysis and the pancreatic elastase-1 stool test were used. Univariate analysis showed that the diameter of the main pancreatic duct and postoperative amylasemia were different in patients with and without pancreatic complications (P = 0.001 and P = 0.002, respectively). Pancreatic exocrine function was reduced and fibrosis was higher in patients without pancreatic complications (P = 0.003 and P = 0.026, respectively). Logistic regression analysis revealed exocrine pancreatic function as an independent risk factor. Pancreas-related morbidity is influenced by pancreatic fibrosis, diameter of pancreatic duct, and exocrine function. Preoperative evaluation of exocrine function allows detection of patients with minimal risk for pancreas-related morbidity.     

On multiple alternating steady states induced by periodic spin phase perturbation waveforms

Direct measurement of neural currents by means of MRI can potentially open a high temporal resolution (10–100 ms) window applicable for monitoring dynamics of neuronal activity without loss of the high spatial resolution afforded by MRI. Previously, we have shown that the alternating balanced steady state imaging affords high sensitivity to weak periodic currents owing to its amplification of periodic spin phase perturbations. This technique, however, requires precise synchronization of such perturbations to the radiofrequency pulses. Herein, we extend alternating balanced steady state imaging to multiple balanced alternating steady states for estimation of neural current waveforms. Simulations and phantom experiments show that the off‐resonance profile of the multiple alternating steady state signal carries information about the frequency content of driving waveforms. In addition, the method is less sensitive than alternating balanced steady state to precise waveform timing relative to radiofrequency pulses. Thus, multiple alternating steady state technique is potentially applicable to MR imaging of the waveforms of periodic neuronal activity. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.     

Insomnia symptoms and mortality: a register‐linked study among women and men from Finland,Norway and Lithuania

Evidence on the association between insomnia symptoms and mortality is limited and inconsistent. This study examined the association between insomnia symptoms and mortality in cohorts from three countries to show common and unique patterns. The Finnish cohort comprised 6605 employees of the City of Helsinki, aged 40–60 years at baseline in 2000–2002. The Norwegian cohort included 6236 participants from Western Norway, aged 40–45 years at baseline in 1997–1999. The Lithuanian cohort comprised 1602 participants from the City of Palanga, aged 35–74 years at baseline in 2003. Mortality data were derived from the Statistics Finland and Norwegian Cause of Death Registry until the end of 2012, and from the Lithuanian Regional Mortality Register until the end of 2013. Insomnia symptoms comprised difficulties initiating sleep, nocturnal awakenings, and waking up too early. Covariates were age, marital status, education, smoking, alcohol, physical inactivity, obesity, diabetes, cardiovascular diseases, depression, shift work, sleep duration, and self‐rated health. Cox regression analysis was used. Frequent difficulties initiating sleep were associated with all‐cause mortality among men after full adjustments in the Finnish (hazard ratio 2.51; 95% confidence interval 1.07–5.88) and Norwegian (hazard ratio 3.42; 95% confidence interval 1.03–11.35) cohorts. Among women and in Lithuania, insomnia symptoms were not statistically significantly associated with all‐cause mortality after adjustments. In conclusion, difficulties initiating sleep were associated with mortality among Norwegian and Finnish men. Variation and heterogeneity in the association between insomnia symptoms and mortality highlights that further research needs to distinguish between men and women, specific symptoms and national contexts, and focus on more chronic insomnia.     

Porosity of Calcium Silicate Hydrates Synthesized from Natural Rocks

In this work, the suitability of natural raw materials with various modifications of SiO₂—granite sawing waste (quartz) and opoka (a mixture of cristobalite, tridymite, quartz, and an amorphous part)—for the 1.13 nm tobermorite and xonotlite synthesis is examined, and their specific surface area, pore diameter and volume, and the predominant pores are determined. Hydrothermal syntheses were carried out at 200 °C for 12 and 72 h from mixtures with a molar ratio of CaO/SiO₂ = 1.0. X-ray diffraction analysis, simultaneous thermal analysis, and scanning electronic microscopy were used, which showed that in the lime–calcined opoka mixture the formation of crystalline calcium silicate hydrates takes place much faster than in the lime–granite sawing waste mixture. The high reactivity of amorphous SiO₂ results in the rapid formation of 1.13 nm tobermorite and xonotlite (12 h). According to Brunauer, Emmet and Taller (BET) analysis data, this product features a specific surface area of ~68 m²/g, a total pore volume of 245 × 10⁻³ cm³/g, and has dominating 1–2.5 nm and 5–20 nm diameter pores. This porosity of the material should provide good thermal insulation properties of the products made from it as no air convection occurs in the fine pores.     

Numerical Analysis of Stapes Prosthesis Constraining in the Case of Otosclerosis

In the case of otosclerosis, it has been noticed that even though there are a variety of different prostheses on the market, due to the anatomical characteristics, it is not always possible to restore excellent mobility to the ossicles and the prosthesis. On the one hand, this happens because the incus long process and the prosthesis create difficult angles. On the other hand, incus necrosis is among the most common causes of the loss of stability to the prosthesis and stapedectomy failure. The aim of this research is to suggest an improvement for stapes prosthesis stability and numerically evaluate the impact of the prosthesis constraining to its dynamical behavior. Numerical 3D models of a standard as well as a modified (adjustable angled) stapes prosthesis were created in order to achieve this aim. Consequently, the modal analysis has been performed to evaluate the mechanical behavior of the prosthesis, assuming that the piston (thick part) would be made of Teflon, and the thin part, fixated on the incus long process, would be made from titanium alloy. Finally, the numerical analysis has been conducted by changing the boundary conditions in respect of the prosthesis constraining, where the attached stapes prosthesis connects to the ossicular chain. Subsequently, there were two hypotheses raised for the prosthesis loop constraining. The first is that during the surgery, the prosthesis is perfectly crimped with certain looseness. The second is that the prosthesis is outgrown by the tissues over time and thus becomes over-constrained. Then, the analyzed standard stapes prosthesis does not fulfil its functions because of the over-constraining that develops over time. An improvement for the standard stapes prosthesis, i.e., a modified stapes prosthesis (adjustable angled), that has been proposed in this research allows avoidance of the negative effects of the over-constrained standard stapes prosthesis that appear over time. Moreover, the proposed modified prosthesis helps to regain hearing when the angle between the incus long process and prosthesis is unfavorable.     

The radical scavenger IAC (bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidinyl) decantionate) decreases mortality, enhances cognitive functions in water maze and reduces amyloid plaque burden in hAβPP transgenic mice

The purpose of this study was to evaluate the efficacy of the radical scavenger IAC (bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidinyl) decantionate) in alleviating behavioral deficits and reducing amyloid-β (Aβ) accumulation in an Alzheimer's disease (AD) transgenic Tg2576 mouse model. Daily treatment with IAC (3-30 mg/kg, i.p.) was started at the age of 6 months and continued until the mice were 13 months old. At the age of 9 months and again at 12 months, the mice were tested in open field and water maze tests. At the age of 13 months, the mice were sacrificed and the brains processed for immunohistochemistry. Mortality was significantly reduced in all IAC-treated groups. In addition, IAC treatment improved the water maze hidden platform training performance but had no effect on motor activity in the open field or water maze swim speed in transgenic mice. Lastly, IAC treatment (10 mg/kg) significantly reduced the cortical Aβ plaque burden. In vitro, IAC is able to increase the number of neurites and neurite branches in cultured cortical primary neurons. In conclusion, IAC slowed down the development of the AD-like phenotype in Tg2576 mice and accelerated neurite growth in cultured neurons.