Factors in gas embolism following laparoscopic injury to vena cava

This study evaluated the incidence and factors involved in the occurrence of gas embolism after laparoscopic injuries. A 5-MHz transesophageal echocardiographic (TEE) probe was placed in 11 anesthetized pigs and used to examine the right cardiac chambers and pulmonary artery. A calibrated carbon dioxide analyzer continuously measured end-tidal carbon dioxide (ETCO2). The ventilatory settings were adjusted to achieve a baseline ETCO2 between 25 and 28 mm Hg. A blinded dose-response curve for TEE and ETCO2 measurements were created by injecting 0.0007 to 1.5 mL/kg of CO2 gas intravenously. Venotomies (N = 22) were created laparoscopically in the inferior vena cava (IVC) of the study animals. All TEE images were videotaped and correlated with laparoscopic events. Embolic episodes were classified by comparison with images recorded during the bolus studies. A variety of methods for obtaining hemostasis and repairing the venotomies were evaluated and their effects on gas embolism were studied. No emboli were noted when the venotomies were bleeding freely, the hole was directly occluded, or the proximal IVC was compressed. Marked embolism was seen with distal IVC occlusion or when there had been significant blood loss. In this situation, manipulation of the hole and higher intraperitoneal pressures led to higher degrees of embolization. No emboli were seen in an open control group except after significant bleeding. The TEE is the most sensitive method of detecting gas emboli; however, the majority of episodes are not clinically significant. Embolism of CO2 occurs when central venous pressure is decreased by blood loss or distal compression. When significant venous bleeding occurs, intravascular volume should be maintained and the bleeding site should be directly occluded

THE LACK OF INHIBITION OF CLAVICEPS PURPUREA POLYGALACTURONASES BY PvPGIP2 MAY EXPLAIN THE FAILURE OF TRANSGENIC WHEAT PLANTS TO RESIST TO THE ERGOT PATHOGEN

Claviceps purpurea is a biotrophic fungal pathogen of cereals and grasses, attacking exclusively young ovaries. C. purpurea grows intercellularly in rye (Secale cereale) ovaries by degrading the pectic polymers and the fungal polygalacturonase (PG) has been shown to be a pathogenicity factor. Two pg genes of C. purpurea, cppg1 and cppg2, are responsible for this activity. Transgenic plants expressing a bean polygalacturonase-inhibiting protein (PvPGIP2) proved to be a valuable tool to increase resistance against PG-producing fungi. However, a stable transgenic PvPGIP2 wheat line, previously shown to be more resistant to the fungal pathogens Bipolaris sorokiniana and Fusarium graminearum, exhibited only a very low reduction of symptoms after infection with C. purpurea. To understand whether this reduced protection of PvPGIP2 in wheat transgenic plants was ascribable to a lack of inhibition against the fungal PGs, we tried to perform inhibition experiments against the C. purpurea PG activity. Unfortunately, this fungus does not produce any PG activity in culture, thus it was necessary to express this activity in a Pichia pastoris heterologous system. The two heterologous expressed PGs, when assayed against the PvPGIP2, were poorly affected by this inhibitor, indicating that the lack of resistance in transformed wheat line may be due to the lack of recognition of the PGs of C. purpurea by PvPGIP2. This finding supports a role of PGIP in plant defence only when PG-PGIP interaction occurs. The expressed PGs may be useful to identify more effective PGIPs by a broad screening of plant PGIPs

The lack of recognition of the polygalacturonases secreted by Claviceps purpurea by PvPGIP2 is responsible for susceptibility in wheat transgenic plants

Claviceps purpurea is a biotrophic fungal pathogen of grasses and cereals, causing the ergot disease. The infection process of C. purpurea spore mimics a pollen grain growing into the ovary during fertilization and the subsequent pathogenic development is strictly limited to the ovary and the connected vascular tissue. The infection process of C. purpurea on rye (Secale cereale) flowers is accompanied by pectin degradation and PG activity represents a pathogenicity factor. Because of the importance of PG in the infection process of rye flower, we tested whether in the interaction system C. purpurea/wheat the presence of PvPGIP2 can affect pathogen infection and ergot disease development. We first verified the expression of PvPGIP2 in the ovary of transgenic wheat line MJ23a that showed a reduced symptom disease caused by Bipolaris sorokiniana and Fusarium graminearum. Subsequently, we evaluated the ergot disease symptoms both by assessing the honeydew production on a scale from 1 to 4 and by measuring the sclerotia weight. Both methods produced slight, though statistically significant, differences in mean value between transgenic and control plants. These data suggest that PvPGIP2 affects pathogen growth but its contribution does not produce a noticeable phenotypic effect on ergot symptoms. To verify the possible reason of these lack of improved resistance in MJ23a transgenic plants, we isolated and expressed in Pichia pastoris both pg genes contained in the C. purpurea genome. In vitro assays using the heterologous expressed proteins and purified PvPGIP2 showed that both PGs are poorly affected by this inhibitor. These data suggests that the lack of increased resistance in MJ23a line is due to the lack of inhibition of the PGs of C. purpurea by PvPGIP2, thus reinforcing the notion of the effectiveness of PGIP as defence response when recognition occurs

Risk of carbon dioxide embolism from laparoscopic venous injuries

Risk of carbon dioxide embolism from laparoscopic venous injurie

Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert

A high-energy neutrino event detected by IceCube on 22 September 2017 was coincident in direction and time with a gamma-ray flare from the blazar TXS 0506+056. Prompted by this association, we investigated 9.5 years of IceCube neutrino observations to search for excess emission at the position of the blazar. We found an excess of high-energy neutrino events, with respect to atmospheric backgrounds, at that position between September 2014 and March 2015. Allowing for time-variable flux, this constitutes 3.5\u3c3 evidence for neutrino emission from the direction of TXS 0506+056, independent of and prior to the 2017 flaring episode. This suggests that blazars are identifiable sources of the high-energy astrophysical neutrino flux

Architecture and performance of the KM3NeT front-end firmware

The KM3NeT infrastructure consists of two deep-sea neutrino telescopes being deployed in the Mediterranean Sea. The telescopes will detect extraterrestrial and atmospheric neutrinos by means of the incident photons induced by the passage of relativistic charged particles through the seawater as a consequence of a neutrino interaction. The telescopes are configured in a three-dimensional grid of digital optical modules, each hosting 31 photomultipliers. The photomultiplier signals produced by the incident Cherenkov photons are converted into digital information consisting of the integrated pulse duration and the time at which it surpasses a chosen threshold. The digitization is done by means of time to digital converters (TDCs) embedded in the field programmable gate array of the central logic board. Subsequently, a state machine formats the acquired data for its transmission to shore. We present the architecture and performance of the front-end firmware consisting of the TDCs and the state machine