Portal hypertension has no role in perioperative bleeding during liver transplantation with systematic porto-caval shunt

BACKGROUND

More than a half of patients undergoing liver transplantation (LT) receive intraoperative transfusion. Portal hypertension (PHT) may contribute to perioperative blood loss. We study the relationship between preoperative hepatic venous pressure gradient (HVPG) values and intraoperative transfusion requirements in adult patients undergoing LT.

METHODS

160 cirrhotic patients undergoing first elective LT (2009-2019) with an HVPG measurement within the previous 6 months were included. Surgical technique was piggyback with portocaval shunt (PCS). The association of HVPG and other variables with transfusion requirements and blood loss were studied.

RESULTS

Blood loss (ml/kg) was positively correlated with HVPG, among other variables, but at multivariable analysis it only remained associated with MELD-Na and HCC indication. Regarding RBC transfusion, MELD-Na and hemoglobin were independently associated with the need and magnitude of RBC transfusion. Subanalysis by surgical stage (hepatectomy, anhepatic, neohepatic) and by serial HVPG cut-offs found no clear associations with either bleeding or transfusion.

DISCUSSION

The severity of PHT plays a minor role on bleeding and transfusion during LT in a contemporary cohort with systematic PCS. Main determinants of transfusion are liver function and baseline hemoglobin, which would seem the suitable goal to optimize transfusion in LT.

DNA dosimeter measurements of beam profile using a novel simultaneous processing technique

A DNA dosimeter (DNAd) was previously developed that uses double-strand breaks (DSB) to measure dose. This dosimeter has been tested to measure dose in scenarios where transient-charged particle equilibrium (TCPE) has been established. The probability of double strand break (PDSB_o), which is the ratio of broken double-stranded DNA (dsDNA) to the initial unbroken dsDNA in the dosimeter, was used to quantify DSBs and related to dose. The goal of this work is to produce a new technique to process and analyze the DNAd and quantify DNA-DSBs. This technique included simultaneously processing multiple DNAds and also establishing a new form to the probability of double strand break (PDSB_n), which was then used to test the DNAd in a non-TCPE condition by taking beam penumbra measurements. The technique utilized a 384-well plate, and the measurements were made at the edge of a 10 × 10 cm field and compared to film measurements. During these penumbra measurements, while observing the positional differences in the higher gradient region at 4.1 and 4.55 cm from the center of the radiation field, the distance to agreement of PDSB_o to film were 0.38 cm and 0.26 cm while the distance to agreement of PDSB_n to film were 0.11 cm and 0.06 cm, respectively. Finally, the developed new separation technique reduced the time needed for the analysis of 25 samples from 200 min to 30 min.

Leaf litter of invasive Chinese tallow (Triadica sebifera) negatively affects hatching success of an aquatic breeding anuran, the Southern Leopard Frog (Lithobates sphenocephalus)

Chinese tallow (Triadica sebifera (L.) Small) is an aggressive invasive tree species that can be abundant in parts of its non-native range. This tree species has the capability of producing monocultures, by outcompeting native trees, which can be in or near wetlands that are utilized by breeding amphibians. Existing research suggests that leaf litter from invasive Chinese tallow reduces survival in larval anurans. The purpose of this study was to determine the effects of Chinese tallow leaf litter on anuran eggs. We exposed eggs of the Southern Leopard Frog ( Lithobates sphenocephalus (Cope, 1886)) at various stages of development to different concentrations of Chinese tallow leaf litter to determine survival. Eggs in the earliest stages of development that we exposed to tallow leaf litter died, regardless of concentration; however, some more-developed eggs exposed to tallow leaf litter did hatch. We determined that the greater the concentration of tallow leaf litter, the lower the dissolved oxygen and pH levels we observed. We suggest that changes in these water-quality parameters are the cause of the observed mortality of anuran eggs in our experiments. Eggs exposed to water containing tallow leaf litter with dissolved oxygen <1.59 mg/L and a pH <5.29 did not survive to hatching.

Circadian activity of the GABAergic system in the golden hamster retina

Daily changes in gamma-aminobutyric acid (GABA) turnover rate were studied in the golden hamster retina. This parameter showed significant variations throughout the light-dark cycle, with minimal values during the day. Retinal glutamic acid decarboxylase (GAD) activity was higher at midnight than at noon. Moreover, [3H]GABA binding significantly varied throughout the 24-h cycle, with maximal values during the day. Saturation studies performed at 12:00 and 24:00 h indicated that the maximal concentration of [3H]GABA binding sites (Bmax) was significantly higher at noon, whereas the dissociation constant (Kd) remained unchanged. High K+-induced GABA release was significantly higher at midnight than at midday. Daily variations in retinal GABA turnover rate, GABA release, and in its specific binding persisted in golden hamsters exposed to constant darkness. In summary, these results support the idea of a circadian clock-controlled GABAergic activity in the hamster retina.

Inactivation of MS-2 phage and poliovirus in groundwater

Since temperature affects the inactivation rate of viruses in natural water systems, the aim of this study was to determine if a temperature shift could influence the structural integrity of model viruses. When crude lysates of MS-2 phage were seeded into groundwater microcosms and incubated at 27 degrees C, complete virus inactivation took place in eight days. The temperature was then shifted to 4 degrees C. Three days after the temperature shift, a two-log increase in virus titer (reactivation) occurred. However, when purified MS-2 lysates were added to groundwater microcosms, no reactivation was obtained. No reactivation of poliovirus took place when similar microcosm experiments were done. The sedimentation coefficients of MS-2 shifted from 80S to 58S, 48S, 37S, 32S, and 18S as inactivation proceeded in groundwater and distilled water controls. Similarly, the sedimentation coefficients of polioviruses changed from 156S to 142S, 135S, 117S, 105S, 95S, and 80 S as inactivation took place. There was no correlation between % virus inactivation and % decrease in virions with intact sedimentation coefficients, as reported earlier for poliovirus inactivated by chlorine. The results presented support our hypothesis that virus inactivation proceeds gradually, involving the rearrangement and (or) loss of capsomere components that may eventually lead to the ejection of nucleic acids. The intermediate particles generated as inactivation proceeds may be in a reversibly inactivated state, and may revert back to a fully infectious state when chemical components stabilize the virus particle.

Mechanisms of the toxic effect of lead. I. Free lead in erythrocyte

In this work, a selection of children was examined based on their free erythrocyte protoporphyrin (FEP) and total blood lead (PbB) contents. Two groups with clear differences in lead sensibility were selected. One group with high FEP levels (deep lead alteration), named "normal," and one group with low FEP levels (discrete lead alteration), named "lead tolerant," and both with similar PbB concentration, were formed. The selection, based on FEP level, showed a correlation with other indicators (neuromotor alterations). A lower activity of the enzymes Glyceraldehyde 3-phosphate dehydrogenase (GA3PD), Glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), and Lactate dehydrogenase (LDH) was found in the normal group when compared to the tolerant group. Therefore, the influence of the lead acetate upon the same erythrocyte enzyme activities was investigated. Lead inhibition of the enzymes GA3PD and G6PD was found, and this inhibition could be related to the free lead content found in the erythrocytes. Inhibition of the enzymes 6PGD and LDH was also found, but these enzymes were not inhibited by exposure to lead acetate. Erythrocyte free lead content was high in the normal group when compared to the lead tolerant group and could be a determinant factor in the biochemical alterations found. Low erythrocyte free lead contents could be an indicator of lead tolerance. TCA-precipitation was found to be a useful method to evaluate free lead content; it gave similar results to gel filtration molecular chromathography.