Propositional Dynamic Logic for Message-Passing Systems

We examine a bidirectional propositional dynamic logic (PDL) for finite and infinite message sequence charts (MSCs) extending LTL and TLC-. By this kind of multi-modal logic we can express properties both in the entire future and in the past of an event. Path expressions strengthen the classical until operator of temporal logic. For every formula defining an MSC language, we construct a communicating finite-state machine (CFM) accepting the same language. The CFM obtained has size exponential in the size of the formula. This synthesis problem is solved in full generality, i.e., also for MSCs with unbounded channels. The model checking problem for CFMs and HMSCs turns out to be in PSPACE for existentially bounded MSCs. Finally, we show that, for PDL with intersection, the semantics of a formula cannot be captured by a CFM anymore

Bacterial Porin Disrupts Mitochondrial Membrane Potential and Sensitizes Host Cells to Apoptosis

The bacterial PorB porin, an ATP-binding beta-barrel protein of pathogenic Neisseria gonorrhoeae, triggers host cell apoptosis by an unknown mechanism. PorB is targeted to and imported by host cell mitochondria, causing the breakdown of the mitochondrial membrane potential (Delta psi(m)). Here, we show that PorB induces the condensation of the mitochondrial matrix and the loss of cristae structures, sensitizing cells to the induction of apoptosis via signaling pathways activated by BH3-only proteins. PorB is imported into mitochondria through the general translocase TOM but, unexpectedly, is not recognized by the SAM sorting machinery, usually required for the assembly of beta-barrel proteins in the mitochondrial outer membrane. PorB integrates into the mitochondrial inner membrane, leading to the breakdown of Delta psi(m). The PorB channel is regulated by nucleotides and an isogenic PorB mutant defective in ATP-binding failed to induce Delta psi(m) loss and apoptosis, demonstrating that dissipation of Delta psi(m) is a requirement for cell death caused by neisserial infection

Bacterial porin disrupts mitochondrial membrane potential and sensitizes host cells to apoptosis

The bacterial PorB porin, an ATP-binding beta-barrel protein of pathogenic Neisseria gonorrhoeae, triggers host cell apoptosis by an unknown mechanism. PorB is targeted to and imported by host cell mitochondria, causing the breakdown of the mitochondrial membrane potential (delta psi m). Here, we show that PorB induces the condensation of the mitochondrial matrix and the loss of cristae structures, sensitizing cells to the induction of apoptosis via signaling pathways activated by BH3-only proteins. PorB is imported into mitochondria through the general translocase TOM but, unexpectedly, is not recognized by the SAM sorting machinery, usually required for the assembly of beta-barrel proteins in the mitochondrial outer membrane. PorB integrates into the mitochondrial inner membrane, leading to the breakdown of delta psi m. The PorB channel is regulated by nucleotides and an isogenic PorB mutant defective in ATP-binding failed to induce delta psi m loss and apoptosis, demonstrating that dissipation of delta psi m is a requirement for cell death caused by neisserial infection

Management approach for recurrent spontaneous pneumothorax in consecutive pregnancies based on clinical and radiographic findings

OBJECTIVE: To describe management and clinical features observed in a patient's seven spontaneous pneumothoraces that developed during two consecutive pregnancies involving both hemithoraces. MATERIALS AND METHODS: A 21 year old former smoker developed three spontaneous left pneumothoraces in the index pregnancy, having already experienced four right pneumothorax events in a prior pregnancy at age 19. RESULTS: Chest tubes were required in several (but not all) hospitalizations during these two pregnancies. Following her fourth right pneumothorax, thoracoscopic excision of right apical lung blebs and mechanical pleurodesis was performed. The series of left pneumothoraces culminated in mini-thoracotomy and thoracoscopically directed mechanical pleurodesis. For both pregnancies unassisted vaginal delivery was performed with no adverse perinatal sequelae. With the exception of multiple pneumothoraces, there were no additional pregnancy complications. CONCLUSION: Spontaneous pneumothorax in pregnancy is believed to be a rare phenomenon, yet the exact incidence is unknown. Here we present the first known case of multiple spontaneous pneumothoraces in two consecutive pregnancies involving both hemithoraces. Clinical management coordinated with obstetrics and surgical teams facilitated a satisfactory outcome for both pregnancies. The diagnosis of pneumothorax should be contemplated in any pregnant patient with dyspnea and chest pain, followed by radiographic confirmation

Chemotherapy-Induced Neuronal Maturation in Sinonasal Teratocarcinosarcoma—a Unique Observation

Sinonasal teratocarcinosarcoma (SNTCS) is a rare and highly malignant tumour with combined features of a teratoma and carcinosarcoma. We report the first case of a SNTCS in 23 year old male treated with neo-adjuvant chemotherapy followed by cranio-facial resection. The resection specimen displayed cellular maturation in the neuroectodermal component. The patient presented with a short history of nasal obstruction, epistaxis and headache. On imaging, a bone destroying lesion of left paranasal sinuses and nasal cavity was identified. The diagnosis of SNTCS could be offered only on the third biopsy which showed heterogeneous admixture of primitive neuroectodermal, epithelial and mesenchymal elements. An adequate sampling with high index of suspicion is needed to catch hold this rare tumor. Tumor was excised after 4 cycles of neo-adjuvant chemotherapy. On microscopic examination, it showed similar epithelial and mesenchymal components as the pretreatment biopsies. However, the primitive neuroectodermal component displayed extensive neuronal maturation. The undifferentiated neuroectodermal cells were completely absent in the post chemotherapy specimen. This case throws light on the morphologic evidence of chemotherapy induced maturation in the neuroectodermal component within SNTCS, an event hitherto not reported in the literature in case of SNTCS