A separated vortex ring underlies the flight of the dandelion

Wind-dispersed plants have evolved ingenious ways to lift their seeds1,2. The common dandelion uses a bundle of drag-enhancing bristles (the pappus) that helps to keep their seeds aloft. This passive flight mechanism is highly effective, enabling seed dispersal over formidable distances3,4; however, the physics underpinning pappus-mediated flight remains unresolved. Here we visualized the flow around dandelion seeds, uncovering an extraordinary type of vortex. This vortex is a ring of recirculating fluid, which is detached owing to the flow passing through the pappus. We hypothesized that the circular disk-like geometry and the porosity of the pappus are the key design features that enable the formation of the separated vortex ring. The porosity gradient was surveyed using microfabricated disks, and a disk with a similar porosity was found to be able to recapitulate the flow behaviour of the pappus. The porosity of the dandelion pappus appears to be tuned precisely to stabilize the vortex, while maximizing aerodynamic loading and minimizing material requirements. The discovery of the separated vortex ring provides evidence of the existence of a new class of fluid behaviour around fluid-immersed bodies that may underlie locomotion, weight reduction and particle retention in biological and manmade structures

Bleeding of gastric ulcers. Epidemiologic, clinical and functional characteristics

The frequency of gastrointestinal haemorrhage due to gastric ulcer has been assessed in 254 personally observed patients suffering from this endoscopically verified pathology. 56 patients, namely 22% of the cases, presented haematemesis and/or melena of the ulcerative lesion. This subgroup was compared with 65 patients with endoscopically verified gastric ulcer without previous bleeding episodes from the lesion in their clinical history, in respect of certain epidemiological, clinical and biohumoral features. The purpose of the study was to check the possible existence of clinical and/or physiopathological differences between subjects with bleeding gastric ulcer and the population of non-bleeding ulcer patients. In 80% of patients studied, the gastric ulcerous disease started with digestive haemorrhage and it was not accompanied by dyspeptic-painful symptomatology in 20% of cases. The pain symptomatology does not appear to be influenced by the intake of non-steroid anti-phlogistic drugs. No significant difference emerges between the two groups considered as regards epidemiological features and biohumoral data (PG I, gastrin, B.A.O. and M.A.O.)

IL SANGUINAMENTO DA ULCERA GASTRICA. CARATTERISTICHE EPIDEMIOLOGICHE, CLINICHE E FUNZIONALI

The frequency of gastrointestinal haemorrhage due to gastric ulcer has been assessed in 254 personally observed patients suffering from this endoscopically verified pathology. 56 patients, namely 22% of the cases, presented haematemesis and/or melena of the ulcertative lesion. This subgroup was compared with 65 patients with endoscopically verified gastric ulcer without previous bleeding episodes from the lesion in their clinical history, in respect of certain epidemiological, clinical and biohumoral features. The purpose of the study was to check the possible existence of clinical and/or physiopathological differences between subjects with bleeding gastric ulcer and the population of non-bleeding ulcer patients. In 80% of patients studied, the gastric ulcerous disease started with digestive haemorrhage and it was not accompanied by dyspeptico-painful symptomatology in 20% of cases. The pain sumptomatology does not appear to be influenced by the intake of non-steroid anti-phlogistic drugs. No significant difference emerges between the two groups considered as regards epidemiological features and biohumoral data (PGI, gastrin, B.A.O. and M.A.O.)

Variants in TRIM22 that affect NOD2 signaling are associated with very early onset inflammatory bowel disease

Severe forms of inflammatory bowel disease (IBD) that develop in very young children can be caused by variants in a single gene. We performed whole-exome sequence (WES) analysis to identify genetic factors that might cause granulomatous colitis and severe perianal disease, with recurrent bacterial and viral infections, in an infant of consanguineous parents.We performed targeted WES analysis of DNA collected from the patient and her parents. We validated our findings by a similar analysis of DNA from 150 patients with very early onset IBD not associated with known genetic factors analyzed in Toronto, Oxford, and Munich. We compared gene expression signatures in inflamed vs. non-inflamed intestinal and rectal tissues collected from patients with treatment-resistant Crohn's disease who participated in a trial of ustekinumab. We performed functional studies of identified variants in primary cells from patients and cell culture.We identified a homozygous variant in the tripartite motif containing 22 gene (TRIM22) of the patient, as well as in 2 patients with a disease similar phenotype. Functional studies showed that the variant disrupted the ability of TRIM22 to regulate nucleotide binding oligomerization domain containing 2 (NOD2)-dependent activation of interferon-beta signaling and NF-κB. Computational studies demonstrated a correlation between the TRIM22-NOD2 network and signaling pathways and genetic factors associated very early onset and adult-onset IBD. The network also associated with antiviral and mycobacterial effectors and markers of inflammation such as fecal calprotectin, c-reactive protein, and Crohn's disease activity index scores.In WES and targeted exome sequence analyses of an infant with severe IBD, characterized by granulomatous colitis and severe perianal disease, we identified a homozygous variant of TRIM22 that affect the ability of its product to regulate NOD2. Combined computational and functional studies showed that the TRIM22-NOD2 network regulates antiviral and anti-bacterial signaling pathways that contribute to inflammation. Further study of this network could lead to new disease markers and therapeutic targets for patients with very early and adult-onset IBD

Variants in TRIM22 that affect NOD2 signaling are associated with very early onset inflammatory bowel disease

Severe forms of inflammatory bowel disease (IBD) that develop in very young children can be caused by variants in a single gene. We performed whole-exome sequence (WES) analysis to identify genetic factors that might cause granulomatous colitis and severe perianal disease, with recurrent bacterial and viral infections, in an infant of consanguineous parents.We performed targeted WES analysis of DNA collected from the patient and her parents. We validated our findings by a similar analysis of DNA from 150 patients with very early onset IBD not associated with known genetic factors analyzed in Toronto, Oxford, and Munich. We compared gene expression signatures in inflamed vs. non-inflamed intestinal and rectal tissues collected from patients with treatment-resistant Crohn's disease who participated in a trial of ustekinumab. We performed functional studies of identified variants in primary cells from patients and cell culture.We identified a homozygous variant in the tripartite motif containing 22 gene (TRIM22) of the patient, as well as in 2 patients with a disease similar phenotype. Functional studies showed that the variant disrupted the ability of TRIM22 to regulate nucleotide binding oligomerization domain containing 2 (NOD2)-dependent activation of interferon-beta signaling and NF-κB. Computational studies demonstrated a correlation between the TRIM22-NOD2 network and signaling pathways and genetic factors associated very early onset and adult-onset IBD. The network also associated with antiviral and mycobacterial effectors and markers of inflammation such as fecal calprotectin, c-reactive protein, and Crohn's disease activity index scores.In WES and targeted exome sequence analyses of an infant with severe IBD, characterized by granulomatous colitis and severe perianal disease, we identified a homozygous variant of TRIM22 that affect the ability of its product to regulate NOD2. Combined computational and functional studies showed that the TRIM22-NOD2 network regulates antiviral and anti-bacterial signaling pathways that contribute to inflammation. Further study of this network could lead to new disease markers and therapeutic targets for patients with very early and adult-onset IBD

Mutations in tetratricopeptide repeat domain 7A result in a severe form of very early onset inflammatory bowel disease.

BACKGROUND and AIMS: Very early onset inflammatory bowel diseases (VEOIBD), including infant disorders, are a diverse group of diseases found in children younger than 6 years of age. They have been associated with several gene variants. Our aim was to identify the genes that cause VEOIBD. METHODS: We performed whole exome sequencing of DNA from 1 infant with severe enterocolitis and her parents. Candidate gene mutations were validated in 40 pediatric patients and functional studies were carried out using intestinal samples and human intestinal cell lines. RESULTS: We identified compound heterozygote mutations in the Tetratricopeptide repeat domain 7 (TTC7A) gene in an infant from non-consanguineous parents with severe exfoliative apoptotic enterocolitis; we also detected TTC7A mutations in 2 unrelated families, each with 2 affected siblings. TTC7A interacts with EFR3 homolog B to regulate phosphatidylinositol 4-kinase at the plasma membrane. Functional studies demonstrated that TTC7A is expressed in human enterocytes. The mutations we identified in TTC7A result in either mislocalization or reduced expression of TTC7A. Phosphatidylinositol 4-kinase was found to co-immunoprecipitate with TTC7A; the identified TTC7A mutations reduced this binding. Knockdown of TTC7A in human intestinal-like cell lines reduced their adhesion, increased apoptosis, and decreased production of phosphatidylinositol 4-phosphate. CONCLUSIONS: In a genetic analysis, we identified loss of function mutations in TTC7A in 5 infants with VEOIBD. Functional studies demonstrated that the mutations cause defects in enterocytes and T cells that lead to severe apoptotic enterocolitis. Defects in the phosphatidylinositol 4-kinase-TTC7A-EFR3 homolog B pathway are involved in the pathogenesis of VEOIBD