Explore the vast range of titles available.

Immunotoxins are rationally designed cancer targeting and killing agents. Disulfide stabilized antibody Fv portion—toxin conjugates (dsFv-toxin) are third generation immunotoxins containing only the antibody fragment variable portions and a toxin fused to the V H or V L . Pseudomonas exotoxin fragment (PE-38) is a commonly used toxin in immunotoxin clinical trials. dsFv-toxin purification was previously published, but the recovery was not satisfactory. This report describes the development of a cGMP production process of the dsFv-toxin that incorporated a novel purification method. The method has been successfully applied to the clinical manufacturing of two dsFv-PE38 immunotoxins, MR1-1 targeting EGFRvIII and HA22 targeting CD22. The two subunits, V L and V H PE-38 were expressed separately in Escherichia coli using recombinant technology. Following cell lysis, inclusion bodies were isolated from the biomass harvested from fermentation in animal source component-free media. The dsFv-toxin was formed after denaturation and refolding, and subsequently purified to homogeneity through ammonium sulfate precipitation, hydrophobic interaction and ion-exchange chromatography steps. It was shown, in a direct comparison experiment using MR1-1 as model protein, that the recovery from the new purification method was improved three times over that from previously published method. The improved recovery was also demonstrated during the clinical production of two dsFv-PE38 immunotoxins—MR1-1 and HA22.

The 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) shows positive evidence for the presence of a low-frequency gravitational-wave (GW) background. In this paper, we investigate potential cosmological interpretations of this signal, specifically cosmic inflation, scalar-induced GWs, first-order phase transitions, cosmic strings, and domain walls. We find that, with the exception of stable cosmic strings of field theory origin, all these models can reproduce the observed signal. When compared to the standard interpretation in terms of inspiraling supermassive black hole binaries (SMBHBs), many cosmological models seem to provide a better fit resulting in Bayes factors in the range from 10 to 100. However, these results strongly depend on modeling assumptions about the cosmic SMBHB population and, at this stage, should not be regarded as evidence for new physics. Furthermore, we identify excluded parameter regions where the predicted GW signal from cosmological sources significantly exceeds the NANOGrav signal. These parameter constraints are independent of the origin of the NANOGrav signal and illustrate how pulsar timing data provide a new way to constrain the parameter space of these models. Finally, we search for deterministic signals produced by models of ultralight dark matter (ULDM) and dark matter substructures in the Milky Way. We find no evidence for either of these signals and thus report updated constraints on these models. In the case of ULDM, these constraints outperform torsion balance and atomic clock constraints for ULDM coupled to electrons, muons, or gluons.

Filopodial actin bundles guide microtubule assembly in the growth cone peripheral (P) domain and retrograde actin-network flow simultaneously transports microtubules rearward. Therefore, microtubule-end position is determined by the sum of microtubule assembly and retrograde transport rates. However, how filopodia actually affect microtubule assembly dynamics is unknown. To address this issue we quantitatively assessed microtubule and actin dynamics before and after selective removal of filopodia. Filopodium removal had surprisingly little effect on retrograde actin-flow rates or underlying network structures, but resulted in an approximate doubling of peripheral microtubule density and deeper penetration of microtubules into the P domain. The latter stemmed from less efficient coupling of microtubules to remaining actin networks and not from a change in microtubule polymer dynamics. Loss of filopodia also resulted in increased lateral microtubule movements and a more randomized microtubule distribution in the P domain. In summary, filopodia do not seem to be formally required for microtubule advance; however, their presence ensures radial distribution of microtubules in the P domain and facilitates microtubule transport by retrograde flow. The resulting dynamic steady state has interesting implications for rapid microtubule-positioning responses in the P domain.

Background The purpose of this study was to investigate the associations between clinical factors and cardiac function as measured by pressure–volume loops (PVLs) in a pediatric heart transplant cohort. Methods Patients (age < 20 years) who underwent heart transplantation presenting for a clinically indicated catheterization were enrolled. PVLs were recorded using microconductance catheters (CD Leycom ® , Zoetermeer, Netherlands). Demographic data, serum B-type natriuretic peptide (BNP), time from transplant, ischemic time, presence of transplant coronary artery disease, donor-specific antibodies, and history of rejection were recorded at the time of catheterization. PVL data included contractility indices: end-systolic elastance and preload recruitable stroke work; ventricular–arterial coupling index; ventricular stiffness constant, Beta; and isovolumic relaxation time constant, tau. Associations between PVL measures and clinical data were investigated using non-parametric statistical tests. Results A total of 18 patients were enrolled. Median age was 8.7 years (IQR 5–14 years). There were ten males and eight females. Six patients had a history of rejection and ten had positive donor-specific antibodies. There was no transplant coronary artery disease. Median BNP was 100 pg/mL (IQR 46–140). Time from transplant to PVL obtained during catheterization procedure was 4.1 years (IQR 1.7–7.8 year). No single clinical characteristic was statistically significant when correlated with PVL data. However, longer ischemic time was associated with worse Beta ( r  = 0.49, p  = 0.05). Conclusions Our study found that longer ischemic times are associated with increased left ventricular stiffness. No other single clinical variable is associated with cardiac dysfunction as determined by PVL analysis.

Chronic NK lymphoproliferative disease of large granular lymphocytes (LDGL) is characterized by the expansion of activated CD3 − , CD16 + or CD56 + lymphocytes. The mechanism of survival of NK cells from LDGL patients is unknown but may be related to antigenic stimulation. There is currently no standard effective therapy for LDGL, and the disease is characteristically resistant to standard forms of chemotherapy. We found evidence of constitutive activation of extracellular-regulated kinase (ERK) in NK cells from 13/13 patients with NK-LDGL (one patient with aggressive and 12 patients with chronic disease). Ablation of ERK activity by inhibitors or a dominant-negative form of MEK, the upstream activator of ERK, reduced the survival of patient NK cells. Ras was also constitutively active in patient NK cells, and exposure of cells to the Ras inhibitor FTI2153 or to dominant-negative-Ras resulted not only in ERK inhibition but also in enhanced apoptosis in both the presence and absence of anti-Fas. Therefore, we conclude that a constitutively active Ras/MEK/ERK pathway contributes to the accumulation of NK cells in patients with NK-LDGL. These findings suggest that strategies to inhibit this signaling pathway may be useful for the treatment of the NK type of LDGL.

Drug development for rare diseases is challenged by small populations and limited data. This makes development of clinical trial protocols difficult and contributes to the uncertainty around whether or not a potential therapy is efficacious. The use of data standards to aggregate data from multiple sources, and the use of such integrated databases to develop statistical models can inform protocol development and reduce the risks in developing new therapies. Achieving regulatory endorsement of such models through defined pathways at the US Food and Drug Administration and European Medicines Authority allows such tools to be used by the drug development community for defined contexts of use without further need for discussion of the underlying model(s). The Duchenne Regulatory Science Consortium (D-RSC) has brought together multiple stakeholders to develop a clinical trial simulation tool for Duchenne muscular dystrophy using such an approach. Here we describe the work of D-RSC as an example of how such an approach may be effective at reducing uncertainty in drug development for rare diseases, and thus bringing effective therapies to patients faster.

Background Roux-en-Y gastric bypass (RYGB) surgery is one of the most commonly performed bariatric surgeries in the United States. Patients with prior RYGB are not amenable to conventional endoscopic retrograde cholangiopancreaticography (ERCP). Surgical gastrostomy (SG) tube placement enables transgastrostomy ERCP (TG-ERCP). Materials and Methods Eleven patients with RYGB anatomy received open Stamm gastrostomy after which the tract was then allowed to mature for an average of 45 days before therapeutic TG-ERCP. The success rate and procedure-related complications of both gastrostomy and ERCP were assessed. Results TG-ERCP was performed on eleven patients (median age 52 years, range 37–61 years) with prior RYGB and pancreatobiliary diseases. Indications for ERCP in these patients included suspected gallstone pancreatitis ( n  = 4), ampullary/biliary strictures ( n  = 5), pancreas divisum ( n  = 1), and common bile duct clipping as a result of RYGB surgery ( n  = 1). Two individuals developed post surgical complications with stomal-related infections. TG-ERCP with therapeutic intervention was successfully performed in all patients. Intervention included stone extractions ( n  = 11), biliary stricture dilation ( n  = 11), biliary sphincterotomy ( n  = 11), biliary ( n  = 3) and pancreatic ( n  = 1) stent placement, ampullary biopsies ( n  = 3), choledochoscopy ( n  = 1), and pseudocyst drainage ( n  = 1). Complications included post-ERCP pancreatitis ( n  = 2), post-sphincterotomy bleeding ( n  = 1), gastrostomy site bleed ( n  = 1), and gastric perforation ( n  = 1). The total number of ERCP sessions for the eleven patients was 15 (1 or 2 per patient). Median follow-up was 42 days (range 7–123 days). Conclusion Surgical open gastrostomy followed by TG-ERCP enables therapeutic intervention but is associated with significant complications.

The detection of a stochastic gravitational wave background by pulsar-timing arrays indicates the presence of a population of supermassive black hole binaries. Although the observed spectrum generally matches predictions for orbital evolution driven by gravitational-wave emission in circular orbits, there is a preference for a spectral turnover at the lowest observed frequencies, which may point to substantial hardening during a transition from early environmental influences to later stages dominated by emission. In the vicinity of these binaries, the ejection of stars or dark matter particles through gravitational three-body slingshots efficiently extracts orbital energy, leading to a low-frequency turnover in the spectrum. Here we model how the gravitational-wave spectrum depends on the initial inner galactic profile before scouring by binary ejections while accounting for a range of initial binary eccentricities. By analysing the NANOGrav 15-year data, we find that a parsec-scale galactic-centre density of around \\(10^6 M_ pc^-3\\) is favoured across most of the parameter space, thus shedding light on the environmental effects that shape black hole evolution and the combined matter density near galaxy centres.