EXTEND (EXTra-uterine Environment for Neonatal Development) is a novel system that promotes physiological development by maintaining the premature lamb in a sterile fluid environment and providing gas exchange via a pumpless arteriovenous oxygenator circuit. During the development of EXTEND, different cannulation strategies evolved with the aim of improving circuit flow. The present study examines how different cannulation strategies affect EXTEND circuit haemodynamics in extreme premature lambs. Seventeen premature lambs were cannulated at gestational ages 105-117 days (term 145-150 days) and supported on EXTEND for up to 4 weeks. Experimental groups were distinguished by cannulation strategy: carotid artery outflow and jugular vein inflow (CA/JV; n = 4), carotid artery outflow and umbilical vein inflow (CA/UV; n = 5) and double umbilical artery outflow and umbilical vein inflow (UA/UV; n = 8). Circuit flows and pressures were measured continuously. As we transitioned from CA/JV to CA/UV to UA/UV cannulation, mean duration of circuit run and weight-adjusted circuit flows increased (P < 0.001) and the frequency of flow interruptions declined (P < 0.05). Umbilical vessels generally accommodated larger-bore cannulas, and cannula calibre was directly correlated with circuit pressures and indirectly correlated with flow:pressure ratio (a measure of post-membrane resistance). We conclude that UA/UV cannulation in fetal lambs on EXTEND optimizes circuit flow dynamics and flow stability and also supports circuit flows that closely approximate normal placental flow.

EXTEND (EXTra‐uterine Environment for Neonatal Development) is a novel system for supporting extremely premature infants that replicates in utero conditions by maintaining a sterile fluid environment and providing gas exchange via a pumpless arteriovenous oxygenator circuit connected to the umbilical vessels. Target gestational age (GA) for EXTEND support in human infants is 23‐27 weeks, when immature lungs are most susceptible to injury in the setting of air ventilation. We previously demonstrated physiologic support of premature lambs cannulated at 105‐117 days GA (lungs developmentally analogous to the 23‐27 week GA human infant) for up to 28 days on EXTEND. In the present study, we sought to determine the technical feasibility of umbilical vessel cannulation in 85‐96 days GA lambs delivered to EXTEND at weights equivalent to the 23‐27 week GA human infant (500‐850 g). Five preterm lambs were cannulated at 85‐96 days GA (term 145 days) and supported on EXTEND for 4‐7 days. All lambs underwent umbilical artery and umbilical vein cannulation. Circuit flows and pressures were monitored continuously, and blood gases were obtained at regular intervals for assessment of oxygen parameters. Systemic pH and lactate were measured at least once daily. Mean body weight at cannulation was 641 ± 71 g (range 480‐850 g). All lambs were cannulated successfully (cannula size varied from 8 to 12 Fr), and mean survival on EXTEND was 140 ± 7 hours. Mean circuit flow was 213 ± 15 mL/kg*min, mean pH was 7.37 ± 0.01, and mean lactate was 1.6 ± 0.2 mmol/L. During the initial 120 hours after EXTEND cannulation, there were no significant differences between 85‐96 days GA lambs and 105‐117 days GA lambs in weight‐adjusted circuit flows, oxygen delivery, pH, or lactate levels. This study demonstrates successful umbilical cord cannulation and adequate circuit flows and oxygen delivery in midgestation lambs size‐matched to the 23‐27 week GA human fetus, which represents an important step in the translation of EXTEND to clinical practice.

The enteric protozoan parasite Entamoeba histolytica is the cause of potentially fatal amebic colitis and liver abscesses. E. histolytica trophozoites colonize the colon, where they induce inflammation, penetrate the mucosa, and disrupt the host immune system. The early establishment of E. histolytica in the colon occurs in the presence of antimicrobial human (LL-37) and murine (CRAMP [cathelin-related antimicrobial peptide]) cathelicidins, essential components of the mammalian innate defense system in the intestine. Studying this early step in the pathogenesis of amebic colitis, we demonstrate that E. histolytica trophozoites or their released proteinases, including cysteine proteinase 1 (EhCP1), induce intestinal cathelicidins in human intestinal epithelial cell lines and in a mouse model of amebic colitis. Despite induction, E. histolytica trophozoites were found to be resistant to killing by these antimicrobial peptides, and LL-37 and CRAMP were rapidly cleaved by released amebic cysteine proteases. The cathelicidin fragments however, did maintain their antimicrobial activity against bacteria. Degradation of intestinal cathelicidins is a novel function of E. histolytica cysteine proteinases in the evasion of the innate immune system in the bowel. Thus, early intestinal epithelial colonization of invasive trophozoites involves a complex interplay in which the ultimate outcome of infection depends in part on the balance between degradation of cathelicidins by amebic released cysteine proteinases and upregulation of proinflammatory mediators which trigger the inflammatory response.T he organism Entamoeba histolytica is a protozoan parasite that causes amebic colitis and liver abscesses through water-and food-borne infection. Approximately 10% of the world's population is infected with Entamoeba, and it is a major cause of death from parasitic infections (29). Colonization of the intestinal tract by E. histolytica follows binding of the amebic surface Gal/GalNAc adherence lectin to epithelial mucin oligosaccharides, with subsequent degradation of the mucin polymer network, extracellular matrix proteins, and components of the innate host defense by released cysteine proteinases (17,20,21,27,28). This early establishment of E. histolytica triggers an inflammatory response, which plays a role in the ultimate outcome of infection (4, 13).Cathelicidins are small cationic antimicrobial peptides of the mammalian innate immune system with broad activity against bacteria (6,10,11,15) and protozoa (7,9,19). LL-37 is the only cathelicidin described in humans (8) and CRAMP (cathelinrelated antimicrobial peptide) is the cathelicidin found in mice (6). Both LL-37 and CRAMP have related structure, function, and distribution in epithelial cells, including the intestine of humans and mice, and are part of the defense against microbial epithelial infections (32). For example, expression of LL-37 mRNA and protein was increased by Helicobacter pylori in gastric epithelial cells (11), and CRAMP protected mice from colonic colonizati...

Background The FDA initially approved pembrolizumab and nivolumab for doses based on patient weight, but subsequently amended approval to fixed doses. We estimated savings from novel dosing strategies based on real‐world patient data from a single cancer center. Methods We analyzed all outpatient doses of pembrolizumab and nivolumab administered at three infusion centers affiliated with our academic hospital between July 1, 2018 and Oct 31, 2018. We estimated savings from several dosing strategies with and without vial sharing between patients. Results A total of 1029 doses of pembrolizumab or nivolumab were administered for multiple cancer types. For 77% of doses, the weight‐based dose was less than the fixed dose. “Dose‐minimization” (DM), defined as the lesser of weight‐based and fixed dose decreased nivolumab spending by 9% without affecting pembrolizumab spending. DM plus vial sharing decreased pembrolizumab spending by 19% without affecting nivolumab. The differences in savings were due to availability of multiple vial sizes for nivolumab but not pembrolizumab. DM plus vial sharing for both drugs would have saved $1.5 million USD over the 4‐month study period. Conclusion New dosing strategies for pembrolizumab and nivolumab can generate large savings without anticipated decrease in efficacy. Barriers include FDA dosing labels, hospital policies against vial sharing, and inaccessibility of smaller vial sizes, which are currently available in other worldwide markets.

Entamoeba histolytica and Giardia lamblia are anaerobic protozoan parasites that cause amebiasis and giardiasis, two of the most common diarrheal diseases worldwide. Current therapy relies on metronidazole, but resistance has been reported and the drug has significant adverse effects. Therefore, it is critical to search for effective, better-tolerated antiamebic and antigiardial drugs. We synthesized several examples of a recently reported class of Hsp90 inhibitors and evaluated these compounds as potential leads for antiparasitic chemotherapy. Several of these inhibitors showed strong in vitro activity against both E. histolytica and G. lamblia trophozoites. The inhibitors were rescreened to discriminate between amebicidal and giardicidal activity and general cytotoxicity toward a mammalian cell line. No mammalian cytotoxicity was found at >100 M for 48 h for any of the inhibitors. To understand the mechanism of action, a competitive binding assay was performed using the fluorescent ATP analogue bis-ANS (4,4=-dianilino-1,1=-binaphthyl-5,5=-disulfonic acid dipotassium salt) and recombinant E. histolytica Hsp90 preincubated in both the presence and absence of Hsp90 inhibitors. There was significant reduction in fluorescence compared to the level in the control, suggesting that E. histolytica Hsp90 is a selective target. The in vivo efficacy and safety of one Hsp90 inhibitor in a mouse model of amebic colitis and giardiasis was demonstrated by significant inhibition of parasite growth at a single oral dose of 5 mg/kg of body weight/day for 7 days and 10 mg/kg/day for 3 days. Considering the results for in vitro activity and in vivo efficacy, Hsp90 inhibitors represent a promising therapeutic option for amebiasis and giardiasis.