Morphology as indicator of adaptive changes of model tissues in osmotically and chemically changing environments.

We investigate the formation and maintenance of the homeostatic state in the case of 2D epithelial tissues following an induction of hyperosmotic conditions, using media enriched with 80 to 320 mOsm of mannitol, NaCl, and urea. We characterise the changes in the tissue immediately after the osmotic shock, and follow it until the new homeostatic state is formed. We characterise changes in cooperative motility and proliferation pressure in the tissue upon treatment with the help of a theoretical model based on the delayed Fisher-Kolmogorov formalism, where the delay in density evolution is induced by the the finite time of the cell division. Finally we explore the adaptation of the homeostatic tissue to highly elevated osmotic conditions by evaluating the morphology and topology of cells after 20 days in incubation. We find that hyperosmotic environments together with changes in the extracellular matrix induce different mechanical states in viable tissues, where only some remain functional. The perspective is a relation between tissue topology and function, which could be explored beyond the scope of this manuscript. Experimental investigation of morphological effect of change of osmotic conditions on long-term tissue morphology and topology Effect of osmotic changes on transient tissue growth behaviour Analysis of recovery process of tissues post-osmotic-shock Toxicity limits of osmolytes in mid- to long-term tissue evolution Tissue adaptation to physiological changes in environment Long-term tissue stabilisation under altered osmotic conditions.

Does Coffee Intake Reduce Postoperative Ileus After Laparoscopic Elective Colorectal Surgery? A Prospective, Randomized Controlled Study: The Coffee Study.

BACKGROUND: Postoperative ileus after colorectal surgery is a frequent problem that significantly prolongs hospital stay and increases perioperative costs. OBJECTIVE: The aim was to evaluate the effect of standardized coffee intake on postoperative bowel movement after elective laparoscopic colorectal resection. DESIGN: This is a prospective randomized controlled trial that was conducted between September 2014 and December 2016. SETTINGS: This study was performed in a public cantonal hospital in Switzerland with accreditation for colon and rectum cancer surgery. PATIENTS: Patients who underwent elective colorectal surgery were included. INTERVENTIONS: Patients were randomly assigned either to the intervention group receiving coffee or the control group receiving tea. A total of 150 mL of the respective beverage was drunk 3 times per day every postoperative day until discharge. MAIN OUTCOME MEASURES: The primary end point was time to first bowel movement. Secondary end points included the use of laxative, insertion of a nasogastric tube, length of hospital stay, and postoperative complications. RESULTS: A total of 115 patients were randomly assigned: 56 were allocated to the coffee group and 59 to the tea group. After coffee intake, the first bowel movement occurred after a median of 65.2 hours versus 74.1 hours in the control group (intention-to-treat analysis; p = 0.008). The HR for earlier first bowel movement after coffee intake was 1.67 (p = 0.009). In the per-protocol analysis, hospital stay was shorter in the coffee group (6 d in the coffee group vs 7 d in the tea group; p = 0.043). LIMITATIONS: The rate of protocol violation, mostly coffee consumption in the tea arm, was relatively high, even if patients were clearly instructed not to consume coffee if they were in the tea arm. CONCLUSIONS: Coffee intake after elective laparoscopic colorectal resection leads to faster recovery of bowel function. Therefore, coffee intake represents a simple and effective strategy to prevent postoperative ileus. See Video Abstract at http://links.lww.com/DCR/A955. TRIAL REGISTRATION: clinicaltrials.gov identifier: NCT02469441.

Utility of Transcutaneous Capnography for Optimization of Non-Invasive Ventilation Pressures.

INTRODUCTION: Nocturnal Non-invasive Positive Pressure Ventilation (NPPV) is the treatment of choice in patients with chronic hypercapnic respiratory failure due to hypoventilation. Continuous oxygen saturation measured with a pulse oximeter provides a surrogate measure of arterial oxygen saturation but does not completely reflect ventilation. Currently, Partial Pressure of Arterial (PaCO2) measured by arterial blood analysis is used for estimating the adequacy of ventilatory support and serves as the gold standard. AIM: To examine the safety, feasibility and utility of cutaneous capnography to re-titrate the non-invasive positive pressure ventilation settings in patients with chronic hypercapnic respiratory failure due to hypoventilation. MATERIALS AND METHODS: Twelve patients with chronic hypercapnic respiratory failure prospectively underwent complete polysomnography and cutaneous capnography measurement on the ear lobe. Non-invasive ventilation pressures were adjusted with the aim of normalizing cutaneous carbon dioxide or at least reducing it by 10 to 15 mmHg. Sensor drift for cutaneous carbon dioxide of 0.7 mmHg per hour was integrated in the analysis. RESULTS: Mean baseline cutaneous carbon dioxide was 45.4 ± 6.5 mmHg and drift corrected awake value was 45.1 ± 8.3 mmHg. The correlation of baseline cutaneous carbon dioxide and the corrected awake cutaneous carbon dioxide with arterial blood gas values were 0.91 and 0.85 respectively. Inspiratory positive airway pressures were changed in nine patients (75%) and expiratory positive airway pressures in eight patients (66%). Epworth sleepiness score before and after the study showed no change in five patients, improvement in six patients and deterioration in one patient. CONCLUSION: Cutaneous capnography is feasible and permits the optimization of non-invasive ventilation pressure settings in patients with chronic hypercapnic respiratory failure due to hypoventilation. Continuous cutaneous capnography might serve as an important additional tool to complement diurnal arterial carbon dioxide tension values.

Liquid crystalline phase formation in suspensions of solid trimyristin nanoparticles.

The presence of liquid crystalline phases in suspensions of solid lipid nanoparticles can increase the risk of their gelling upon administration through fine needles. Here we study the formation of liquid crystalline phases in aqueous suspensions of platelet-like shaped solid lipid nanoparticles. A native lecithin-stabilized trimyristin (20 wt %) suspension was investigated at different dilution levels by small-angle X-ray scattering (SAXS) and visual inspection of their birefringence between two crossed polarizers. For trimyristin concentrations φMMM < 6 wt %, the dispersed platelets are well separated from each other whereas they start to self-assemble into stacked lamellae for 6 wt % ≤ φMMM < 12 wt %. For φMMM ≥ 12 wt %, the SAXS patterns become increasingly anisotropic, which is a signature of an evolving formation of a preferred orientation of the platelets on a microscopic scale. Simultaneously, the suspensions become birefringent, which proves the existence of an anisotropic liquid crystalline phase formed in the still low viscous liquid suspensions. Spatially resolved SAXS scans and polarization microscopy indicate rather small domains in the (sub)micrometer size range in the nematic liquid crystalline phase and the presence of birefringent droplets (tactoids). The observed critical concentrations for the formation of stacks and the liquid crystalline phase are significantly higher as for equivalent suspensions prepared from triglycerides with longer chains. This can be explained with the lower aspect ratio of trimyristin platelets. Special emphasis is put on the isotropic-liquid crystalline phase transition as a function of the ionic strength of the dispersion medium and φMMM. Higher salt concentrations allow shifting of the phase transition to higher trimyristin concentrations. This can be attributed to a partial screening of the repulsive forces between the platelets, which allows higher packing densities within the platelet stacks and of remaining isolated platelets.

Formation of liquid crystalline phases in aqueous suspensions of platelet-like tripalmitin nanoparticles.

Suspensions of platelet-like shaped tripalmitin nanocrystals stabilized by the pure lecithin DLPC and the lecithin blend S100, respectively, have been studied by small-angle x-ray scattering (SAXS) and optical observation of their birefringence at different tripalmitin (PPP) concentrations φ(PPP). It could be demonstrated that the platelets of these potential drug delivery systems start to form a liquid crystalline phase already at pharmaceutically relevant concentrations φ(PPP) of less than 10 wt. %. The details of this liquid crystalline phase are described here for the first time. As in a previous study [A. Illing et al., Pharm. Res. 21, 592 (2004)] some platelets are found to self-assemble into lamellar stacks above a critical tripalmitin concentration φ(PPP)(st) of 4 wt. %. In this study another critical concentration φ(PPP)(lc) ≈ 7 wt. % for DLPC and φ(PPP)(lc) ≈ 9 wt. % for S100 stabilized dispersions, respectively, has been observed. φ(PPP)(lc) describes the transition from a phase of randomly oriented stacked lamellae and remaining non-assembled individual platelets to a phase in which the stacks and non-assembled platelets exhibit an overall preferred orientation. A careful analysis of the experimental data indicates that for concentrations above φ(PPP)(lc) the stacked lamellae start to coalesce to rather small liquid crystalline domains of nematically ordered stacks. These liquid crystalline domains can be individually very differently oriented but possess an overall preferred orientation over macroscopic length scales which becomes successively more expressed when further increasing φ(PPP). The lower critical concentration for the formation of liquid crystalline domains of the DLPC-stabilized suspension compared to φ(PPP)(lc) of the S100-stabilized suspension can be explained by a larger aspect ratio of the corresponding tripalmitin platelets. A geometrical model based on the excluded volumes of individual platelets and stacked lamellae has been developed and successfully applied to reproduce the critical volume fractions for both, the onset of stack formation and the appearance of the liquid crystalline phase.

Fewer nutrient deficiencies after laparoscopic sleeve gastrectomy (LSG) than after laparoscopic Roux-Y-gastric bypass (LRYGB)-a prospective study.

BACKGROUND: Deficiencies in micronutrients after bariatric operations are frequent, despite routine supplementation. Main outcome measures were pre- and postoperative frequency of nutrient deficiencies and success rate of their treatment. METHODS: Between 5/2004 and 12/2006, 136 patients (m:f = 0:4) with an average body mass index of 45 (35-58) kg/m(2) and age of 53 (21-66) years were prospectively analysed. Laparoscopic Roux-Y-gastric bypass (LRYGB) was performed in 86 patients and laparoscopic sleeve gastrectomy (LSG) was performed in 50 patients. The patients were examined before surgery as well as 3, 6, 12, 24, 30, and 36 months postoperatively using a standard protocol including laboratory tests. The mean follow-up time was 24.4 (12-40) months; the follow-up rate was 100%. RESULTS: Prior to surgery, 57% of the patients had at least one deficiency, 23% of whom had vitamin D(3) deficiency. Frequent postoperative deficiencies after LSG were zinc, vitamin D(3), folic acid, iron, and vitamin B(12); after LRYGB, vitamin B(12), vitamin D(3), zinc, and secondary hyperparathyroidism. No vitamin B(1) or B(6) deficiencies were found. Calcium levels were normal in all patients. Treatment of the deficiencies was mostly successful. CONCLUSION: Preoperatively, 57% of morbidly obese patients already had a deficiency. Postoperatively, significantly more vitamin B(12) and vitamin D deficiencies and hyperparathyroidism were found in patients who had undergone LRYGB. After LSG, folate deficiency was more frequent (but not significantly so). Calcium levels were normal in all patients; therefore, parathyroid hormone and vitamin D(3) levels are more sensitive markers for early detection of disorders of calcium metabolism. Iron deficiency anaemia is most efficiently treated by IV therapy.