Fibrosis impairs the formation of new myofibers in the soft palate after injury

Muscle repair is a crucial component of palatoplasty but little is known about muscle regeneration after cleft palate repair. We hypothesized that the formation of new myofibers is hampered by collagen accumulation after experimental injury of the soft palate of rats. One‐millimeter excisional defects were made in the soft palates of 32 rats. The wound area was evaluated after 3, 7, 28, and 56 days using azocarmine G and aniline blue to stain for collagen and immunohistochemistry to identify myofibroblasts and to monitor skeletal muscle differentiation. To evaluate age effects, 16 unwounded animals were evaluated at 3 and 56 days. Staining was quantified by image analysis, and one‐way ANOVA was used for the statistical analysis. At day 56, the area percentage of collagen‐rich tissue was higher in the injured palatal muscles (46.7 ± 6.9%) than in nonwounded controls (15.9 ± 1.0%, p < 0.05). Myofibroblasts were present in the injured muscles at days 3 and 7 only. The numbers of proliferating and differentiating myoblasts within the wound area were greater at day 7 (p < 0.05), but only a few new myofibers had formed by 56 days. No age effects were found. The results indicate that surgical wounding of the soft palate results in muscle fibrosis. Although activated satellite cells migrated into the wound area, no new myofibers formed. Thus, regeneration and function of the soft palate muscles after injury may be improved by regenerative medicine approaches.     

Improved prediction of protein secondary structure by use of sequence profiles and neural networks.

The explosive accumulation of protein sequences in the wake of large-scale sequencing projects is in stark contrast to the much slower experimental determination of protein structures. Improved methods of structure prediction from the gene sequence alone are therefore needed. Here, we report a substantial increase in both the accuracy and quality of secondary-structure predictions, using a neural-network algorithm. The main improvements come from the use of multiple sequence alignments (better overall accuracy), from "balanced training" (better prediction of beta-strands), and from "structure context training" (better prediction of helix and strand lengths). This method, cross-validated on seven different test sets purged of sequence similarity to learning sets, achieves a three-state prediction accuracy of 69.7%, significantly better than previous methods. In addition, the predicted structures have a more realistic distribution of helix and strand segments. The predictions may be suitable for use in practice as a first estimate of the structural type of newly sequenced proteins.     

Effect of left ventricular remodeling after cardiac resynchronization therapy on frequency of ventricular arrhythmias

We evaluated whether cardiac resynchronization therapy affects the prevalence of ventricular tachycardia in relation to reverse remodeling in patients with end-stage heart failure. Clinical, echocardiographic, and implantable cardioverter-defibrillator (ICD) data of 17 patients with ICDs were obtained before and after they had received an upgrade to an ICD-cardiac resynchronization therapy device.     

Lineage fate of ductular reactions in liver injury and carcinogenesis

Ductular reactions (DRs) are observed in virtually all forms of human liver disease; however, the histogenesis and function of DRs in liver injury are not entirely understood. It is widely believed that DRs contain bipotential liver progenitor cells (LPCs) that serve as an emergency cell pool to regenerate both cholangiocytes and hepatocytes and may eventually give rise to hepatocellular carcinoma (HCC). Here, we used a murine model that allows highly efficient and specific lineage labeling of the biliary compartment to analyze the histogenesis of DRs and their potential contribution to liver regeneration and carcinogenesis. In multiple experimental and genetic liver injury models, biliary cells were the predominant precursors of DRs but lacked substantial capacity to produce new hepatocytes, even when liver injuries were prolonged up to 12 months. Genetic modulation of NOTCH and/or WNT/β-catenin signaling within lineage-tagged DRs impaired DR expansion but failed to redirect DRs from biliary differentiation toward the hepatocyte lineage. Further, lineage-labeled DRs did not produce tumors in genetic and chemical HCC mouse models. In summary, we found no evidence in our system to support mouse biliary-derived DRs as an LPC pool to replenish hepatocytes in a quantitatively relevant way in injury or evidence that DRs give rise to HCCs.     

A 3-base pair deletion,c.9711_9713del,in DMD results in intellectual disability without muscular dystrophy

We have identified a deletion of 3 base pairs in the dystrophin gene (DMD), c.9711_9713del, in a family with nonspecific X-linked intellectual disability (ID) by sequencing of the exons of 86 known X-linked ID genes. This in-frame deletion results in the deletion of a single-amino-acid residue, Leu3238, in the brain-specific isoform Dp71 of dystrophin. Linkage analysis supported causality as the mutation was present in the 7.6 cM linkage interval on Xp22.11–Xp21.1 with a maximum positive LOD score of 2.41 (MRX85 locus). Molecular modeling predicts that the p.(Leu3238del) deletion results in the destabilization of the C-terminal domain of dystrophin and hence reduces the ability to interact with β-dystroglycan. Correspondingly, Dp71 protein levels in lymphoblastoid cells from the index patient are 6.7-fold lower than those in control cell lines (P=0.08). Subsequent determination of the creatine kinase levels in blood of the index patient showed a mild but significant elevation in serum creatine kinase, which is in line with impaired dystrophin function. In conclusion, we have identified the first DMD mutation in Dp71 that results in ID without muscular dystrophy.     

ATG16L1 and NOD2 polymorphisms enhance phagocytosis in monocytes of Crohn’s disease patients

AIM:To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn’s disease(CD).METHODS:In this study,we assessed the differential responses in phagocytosis by measuring the phagocytic activity and the percentage of active phagocytic monocytes and granulocytes in inflammatory bowel disease patients as well as healthy controls.As both autophagy related like 1(ATG16L1)and immunityrelated guanosine triphosphatase gene are autophagy genes associated with CD and more recently nucleo-tide-binding ligomerization domain-containing protein2(NOD2)has been identified as a potent inducer of autophagy we genotyped the patients for these variants and correlated this to the phagocytic reaction.The genotyping was done with restriction fragment length polymorphisms analysis and the phagocytosis was determined with the pHrodo?Escherichia coli Bioparticles Phagocytosis kit for flowcytometry.RESULTS:In this study,we demonstrate that analysis of the monocyte and granulocyte populations of patients with CD and ulcerative colitis showed a comparable phagocytic activity(ratio of mean fluorescence intensity)between the patient groups and the healthy controls.CD patients show a significantly higher phagocytic capacity(ratio mean percentage of phagocytic cells)compared to healthy controls(51.91%±2.85%vs 37.67%±7.06%,P=0.05).The extend of disease was not of influence.However,variants of ATG16L1(WT:2.03±0.19 vs homozygoot variant:4.38±0.37,P<0.009)as well as NOD2(C-ins)(heterozygous variant:42.08±2.94 vs homozygous variant:75.58±4.34(P=0.05)are associated with the phagocytic activity in patients with CD.CONCLUSION:Monocytes of CD patients show enhanced phagocytosis associated with the presence of ATG16L1 and NOD2 variants.This could be part of the pathophysiological mechanism resulting in the disease.     

Tribonucleation of bubbles

We report on the nucleation of bubbles on solids that are gently rubbed against each other in a liquid. The phenomenon is found to depend strongly on the material and roughness of the solid surfaces. For a given surface, temperature, and gas content, a trail of growing bubbles is observed if the rubbing force and velocity exceed a certain threshold. Direct observation through a transparent solid shows that each bubble in the trail results from the early coalescence of several microscopic bubbles, themselves detaching from microscopic gas pockets forming between the solids. From a detailed study of the wear tracks, with atomic force and scanning electron microscopy imaging, we conclude that these microscopic gas pockets originate from a local fracturing of the surface asperities, possibly enhanced by chemical reactions at the freshly created surfaces. Our findings will be useful either for preventing undesired bubble formation or, on the contrary, for “writing with bubbles,” i.e., creating controlled patterns of microscopic bubbles.Elementary considerations show that a bubble will spontaneously disappear unless its radius r is larger than a critical value r_c = 2γ/ΔP, where γ is the surface tension of the liquid and ΔP is the difference between the pressure of the bubble contents and the surrounding liquid (1). Only bubbles larger than r_c can persist and grow by gas diffusion and liquid evaporation. The classical kinetic theory of nucleation (2) shows that, for water, the spontaneous formation of critical bubbles requires either superheats of 212 °C or negative pressures (i.e., tensions) of 140 MPa. Recent experiments have come close to the quantitative verification of these predictions (3, 4), but only at the cost of a great deal of sophistication and ingenuity. It must therefore be concluded that a different mechanism is responsible for the exceedingly commonplace occurrence of bubbles.The seed for the currently accepted explanation was planted by Gernez (5) who, in 1867, hypothesized that bubbles start from a preexisting gaseous nucleus lodged in solid impurities or the walls of the container. An explanation for the stability of these heterogeneous nuclei was later supplied by Harvey et al. (6) who pointed out that the curvature induced by contact with a hydrophobic solid surface would be able to stabilize a gas pocket even in an undersaturated liquid. This “crevice model” of bubble nucleation explains a large number of observations and has been applied to the development of so-called enhanced boiling surfaces (7, 8). Gas bubbles can be further stabilized by the formation of organic skins at their surface (9, 10).Despite these advances, the nucleation phenomenon still exhibits obscure facets, one of which—tribonucleation—is studied in this paper. It has been known for at least half a century that, as noticed by Hayward in 1967 (11), “extremely gentle rubbing” of two solid objects inside a liquid under tension, which is otherwise stable against most forms of mechanical action (e.g., knocking on the container wall or stirring), readily induces nucleation. This tribonucleation is often cited as a plausible source of the microbubbles found in the limbs of humans and animals after physical exercise (12, 13). Campbell (14) and Ikels (15) attributed the nucleation observed in these conditions to the pressure drop induced by the viscous flow in the space between two separating solid surfaces. Indeed, in highly viscous liquids, bubble formation compatible with this picture has been reported (16–18). However, this explanation cannot easily account for the nucleation observed in low-viscosity fluids like water and ethanol, because in many cases the theoretical gap between the solids would have to be smaller than the surface roughness. More strikingly, it cannot account for the key observation by Hayward that bubbles do not nucleate in the case of a rolling motion, but only in the case of a sliding motion between the solids (11), although for the same force and velocity the pressure drop is expected to be twice as large for rolling than for sliding (19). Another instance of bubble nucleation upon solid–solid contact in a low-viscosity liquid was reported by Theofanous et al. (20). These authors were able to reliably nucleate single bubbles by gently bringing into contact two stainless-steel wires in Freon superheated by up to 60 °C.In this paper, we present experiments in which we rub a bead against a wafer submerged in a low-viscosity liquid. We vary the rubbing force and velocity, the temperature, and the materials of the solids. Our approach is to combine macroscopic observations, revealing a threshold for the rubbing-induced nucleation, with microscopic observations at the smallest scales of the problem: that of the apparent (Hertz) contact between the solids and that of the roughness tips where the actual contact is realized.     

School-Related and Social–Emotional Outcomes of Providing Mental Health Services in Schools

This study evaluated student outcomes of an expanded school mental health (ESMH) model that placed community mental health clinicians on-site in schools to identify and treat children with mental health needs. The first aim of this study was to consider school-related outcomes (suspension rates and attendance rates) for those students who received ESMH treatment (n = 159) were compared to a matched high-risk sample that did not receive such services (n = 148). Results demonstrated differences between groups over time on measures of suspensions and attendance but not academic achievement. The second aim of this study was to evaluate change in social–emotional functioning (Strengths and Difficulties Questionnaire Scores) over time for the treatment group. Results indicated significant improvements on several parent and teacher ratings. Despite limitations of the ESMH framework examined in this study, the overall results suggest some promising advantages for students who received ESMH services.