Assembly of Tight Junction Strands: Claudin-10b and Claudin-3 Form Homo-Tetrameric Building Blocks that Polymerise in a Channel-Independent Manner.

Tight junctions regulate paracellular permeability size and charge selectively. Models have been proposed for the molecular architecture of tight junction strands and paracellular channels. However, they are not fully consistent with experimental and structural data. Here, we analysed the architecture of claudin-based tight junction strands and channels by cellular reconstitution of strands, structure-guided mutagenesis, in silico protein docking and oligomer modelling. Prototypic channel- (Cldn10b) and barrier-forming (Cldn3) claudins were analysed. Förster resonance energy transfer (FRET) assays indicated multistep claudin polymerisation, starting with cis-oligomerization specific to the claudin subtype, followed by trans-interaction-triggered cis-polymerisation. Alternative protomer interfaces were modelled in silico and tested by cysteine-mediated crosslinking, confocal- and freeze fracture EM-based analysis of strand formation. The analysed claudin mutants included also mutations causing the HELIX syndrome. The results indicated that protomers in Cldn10b and Cldn3 strands form similar antiparallel double rows, as has been suggested for Cldn15. Mutually stabilising -hydrophilic and hydrophobic - cis- and trans-interfaces were identified that contained novel key residues of extracellular segments ECS1 and ECS2. Hydrophobic clustering of the flexible ECS1 ß1ß2 loops together with ECS2-ECS2 trans-interaction is suggested to be the driving force for conjunction of tetrameric building blocks into claudin polymers. Cldn10b and Cldn3 are indicated to share this polymerisation mechanism. However, in the paracellular centre of tetramers, electrostatic repulsion may lead to formation of pores (Cldn10b) and electrostatic attraction to barriers (Cldn3). Combining in vitro data and in silico modelling, this study improves mechanistic understanding of paracellular permeability regulation by elucidating claudin assembly and its pathologic alteration as in HELIX syndrome.

PROTECTIVE EFFECT OF NIGELLA SATIVA OIL ON MYOCARDIUM IN STREPTOZOTOCIN-INDUCED DIABETIC RATS.

BACKGROUND: To evaluate the protective effect of Nigella sativa oil (NSO) on the myocardium in streptozotocin-induced diabetic rats. MATERIALS AND METHODS: Thirty-two 7-8-week-old female Wistar albino rats (300-350 g) were equally divided into 4 groups: nondiabetic untreated animals (control), diabetes mellitus (DM), NSO, and DM+NSO groups. For the induction of diabetes, 45 mg/kg streptozotocin was applied to the rats in the DM and DM+NSO groups as a single intraperitoneal dose. NSO (400 mg/kg) was orally administered through an intragastric catheter once a day over 21 days. Formalin-fixed, paraffin-embedded tissue sections of the myocardium were evaluated histopathologically and immunohistochemically. RESULTS: Compared to the control, NSO, and DM+NSO groups, the myocardial tissue samples from the rats in the DM group had significantly higher myositis, hyaline degeneration, and Zenker's necrosis. Moreover, the Bcl-2 expressions were significantly higher in the control, NSO, and DM+NSO groups than in the DM group. CONCLUSION: NSO has a protective effect on the myocardium of streptozotocin-induced diabetic rats, most likely via suppressing apoptosis.

To what extent can local anesthetics be reduced for infraclavicular block with ultrasound guidance?

OBJECTIVES: To assess the adequacy of different amounts of local anesthetics (LA) in infraclavicular blockade (ICB) under ultrasonographic (US) guidance and neurostimulation and compare them to the conventional doses under neurostimulation (NS). MATERIAL AND METHODS: In this study 100 patients scheduled for upper limb surgery and suitable for ICB were randomly allocated to 1 of 5 groups: group NS (NS alone group 0.5 ml/kg LA), group FD (full-dose US group 0.5 ml/kg LA), group 30 (30% reduced dose LA 0.35 ml/kg), group 50 (0.25 ml/kg LA) and group 70 (0.15 ml/kg LA). The ICB was performed under US in conjunction with NS in all groups except group NS in which neurostimulation was used alone. When necessary local anesthetic supplementation to the operation site was administered during surgery and propofol infusion for sedation ensued. Evaluation of sensory and motor block was performed for each terminal nerve (i.e. radial, ulnar, median and musculocutaneous nerves). Block quality (assessing the need for rescue LA and propofol sedation) and duration of the block were documented. RESULTS: None of the patients in the FD and 30 groups required any supplementation or sedation, whereas LA supplementation rates were 5% in group 50 and 10% in groups 70 and NS. The propofol sedation rates were 20% in group NS, 25% in group 50 and 40% in group 70. Sensory block was significantly better in groups FD, 30 and NS at 30 min. A complete block was achieved more rapidly in all nerve territories in the full-dose group (p = 0.0001). Block duration was longest in group FD and was significantly longer in group 30 than in the other two groups (p = 0.0001). CONCLUSION: The results show that US guidance is more effective in maintenance of successful ICB than neurostimulation guidance alone and a reduction of LA doses even to 70% of conventionally used doses seems possible with US guidance. This article is published in English.

Diffuse soft tissue and vascular calcification in systemic lupus erythematosus with chronic kidney disease.

The systemic disorder of mineral and bone metabolism which is related to chronic kidney disease (CKD) is called mineral and bone disorder (MBD). Calcifications related to CKD-MBD may occur in ophthalmic tissue, arterial walls, subcutaneous and periarticular soft tissues and organs. The vascular calcifications are the most important causes of mortality and morbidity in CKD. Here, we present a case of systemic lupus erythematosus with early and disseminated calcifications of vascular and periarticular soft tissues related to CKD-MBD.

Vaginal neurofibroma in a hysterectomized poodle dog.

A 15-year-old, spayed, female poodle dog was presented for evaluation of a mass of tissue prolapsed from the vulva. The dog had been hysterectomized when it was 5 years old. A vaginal mass had been removed approximately 10 months before presentation. Haematological and serum biochemistry analyses demonstrated mild leucocytosis and glycaemia. A vaginal smear was predominantly made up of parabasal cells and intermediate cells with no neoplastic cells. Thoracal and abdominal radiographic findings were unremarkable. The ovaries could not be identified using abdominal ultrasonography. A midline exploratory laparotomy identified both ovaries that were surgically excised. The vaginal mass was also removed following an episiotomy procedure. Histopathological examination of the mass demonstrated that it was a neurofibroma. Both ovaries had cystic changes. Four months after the surgery, the owner reported that the dog was clinically normal. To the authors' knowledge, this is the first reported case of a vaginal neurofibroma after an incomplete ovariohysterectomy in the dog.

Primary peritoneal spindle cell sarcoma presented with massive ascites: a case report.

Soft tissue sarcomas (STSs) are a heterogeneous group of rare neoplasms originating from the embryonic mesoderm and mesenchymal cells. Primary peritoneal sarcomas have been reported as leiomyosarcoma, liposarcoma and carcinosarcoma. However, primary peritoneal spindle cell sarcoma has never been reported in the literature. Herein, we report on a 38-year-old woman with massive ascites diagnosed as primary peritoneal spindle cell sarcoma. Following doxorubicin and ifosfamide chemotherapy, her symptoms improved and ascites regressed. Other primary peritoneal sarcomas rarely cause massive ascites. We suggest that in patients presenting with massive exudative ascites associated with malignancy, primary peritoneal sarcomas should be also considered in the differential diagnosis.

Hydatid cyst presenting as a soft-tissue calf mass in a child.

Hydatid disease caused by Echinococcus granulosus often manifests as a slow growing cystic mass; it mainly affects the liver or lung and rarely other parts of the body such as the brain, heart, spleen, peritoneal cavity, or bone. Hydatid cysts of the musculoskeletal system are rare. Since the intramuscular hydatid cyst closely resembles a soft-tissue tumor on clinical examination, the preoperative radiological diagnosis is very important for the identification of the lesion prior to surgery. We describe a rare case of primary intramuscular hydatidosis in a child, together with its clinical presentation and radiological and histological findings. The treatment principles for hydatid cysts are also discussed.

Pediatric diffuse lipoblastomatosis of the foot -- a case report and review of the literature.

Diffuse lipoblastomatosis is a rare lipomatous tumor of infancy that derives from fetal-embryonal fat. It usually affects infants and children and presents as a superficial mass that extends from the subcutis to the underlying muscle in the upper or lower extremities. In spite of its benign nature, the tumor may behave in a locally aggressive manner and invade the surrounding tissues. A case of isolated diffuse lipoblastomatosis of a 5-year-old boy in the plantar aspect of his right foot that has not been documented in that area before is described. The clinical and radiological presentation and histologic evaluation of diffuse lipoblastomatosis are discussed, in order to make a differential diagnosis between this rare tumor and other soft tissue tumors. In addition, the treatment principles of the tumor are described. This case demonstrates that diffuse lipoblastomatosis can be difficult to diagnose without histologic evaluation and, once diagnosed, should be treated by adequate surgical excision in order to prevent recurrence.