Spreading of COVID-19 in Italy as the spreading of a wave packet

We find that the spreading of the COVID-19 pandemic in Italy can be described as the propagation of a wave packet in a dispersive medium where the effect of lockdown is simulated by the dispersion relation of the medium. We start expanding a previous statistical analysis based on the official data provided by the Italian Civil Protection during 100 days, from March 2nd to June 9th. As the total number of people infected with the virus is uncertain, we have considered the trend of ICU patients and the sum of hospitalized patients and the deceased. Both the corresponding curves are well approximated by the same function depending on four free parameters. The model allows to predict the short-term behavior of the pandemic and to estimate the benefits due to lockdown measures.

Novel Catalytically-Inactive PII Metalloproteinases from a Viperid Snake Venom with Substitutions in the Canonical Zinc-Binding Motif

Snake venom metalloproteinases (SVMPs) play key biological roles in prey immobilization and digestion. The majority of these activities depend on the hydrolysis of relevant protein substrates in the tissues. Hereby, we describe several isoforms and a cDNA clone sequence, corresponding to PII SVMP homologues from the venom of the Central American pit viper Bothriechis lateralis, which have modifications in the residues of the canonical sequence of the zinc-binding motif HEXXHXXGXXH. As a consequence, the proteolytic activity of the isolated proteins was undetectable when tested on azocasein and gelatin. These PII isoforms comprise metalloproteinase and disintegrin domains in the mature protein, thus belonging to the subclass PIIb of SVMPs. PII SVMP homologues were devoid of hemorrhagic and in vitro coagulant activities, effects attributed to the enzymatic activity of SVMPs, but induced a mild edema. One of the isoforms presents the characteristic RGD sequence in the disintegrin domain and inhibits ADP- and collagen-induced platelet aggregation. Catalytically-inactive SVMP homologues may have been hitherto missed in the characterization of snake venoms. The presence of such enzymatically-inactive homologues in snake venoms and their possible toxic and adaptive roles deserve further investigation.

Muscle Tissue Damage Induced by the Venom of Bothrops asper: Identification of Early and Late Pathological Events through Proteomic Analysis

The time-course of the pathological effects induced by the venom of the snake Bothrops asper in muscle tissue was investigated by a combination of histology, proteomic analysis of exudates collected in the vicinity of damaged muscle, and immunodetection of extracellular matrix proteins in exudates. Proteomic assay of exudates has become an excellent new methodological tool to detect key biomarkers of tissue alterations for a more integrative perspective of snake venom-induced pathology. The time-course analysis of the intracellular proteins showed an early presence of cytosolic and mitochondrial proteins in exudates, while cytoskeletal proteins increased later on. This underscores the rapid cytotoxic effect of venom, especially in muscle fibers, due to the action of myotoxic phospholipases A2, followed by the action of proteinases in the cytoskeleton of damaged muscle fibers. Similarly, the early presence of basement membrane (BM) and other extracellular matrix (ECM) proteins in exudates reflects the rapid microvascular damage and hemorrhage induced by snake venom metalloproteinases. The presence of fragments of type IV collagen and perlecan one hour after envenoming suggests that hydrolysis of these mechanically/structurally-relevant BM components plays a key role in the genesis of hemorrhage. On the other hand, the increment of some ECM proteins in the exudate at later time intervals is likely a consequence of the action of endogenous matrix metalloproteinases (MMPs) or of de novo synthesis of ECM proteins during tissue remodeling as part of the inflammatory reaction. Our results offer relevant insights for a more integrative and systematic understanding of the time-course dynamics of muscle tissue damage induced by B. asper venom and possibly other viperid venoms.

[Cranial trauma and prehospital care. Evaluation of the effectiveness of early treatment]

The role of pre-hospital care is still to be stressed especially in case of head injuries. We compared two groups of head injuries (total 50 patients, 38 politrauma) transported by traditional ambulance (28 patients) or by EMS helicopter (22). The two populations had similar values of the considered indices (TS, ISS, GCS, TRISS). They significantly were different only for the "free therapy time". Patients transported by ambulance showed an higher incidence (p less than 0.01) of acute complications (like hemorrhage and hypovolemic shock) despite the same gravity score indices. The index applied for the follow-up valuation, does not show any difference in the two groups. This may be due to the unreliability of the used scores if they are applied without any correlation with the quality of care during the transport.