Understanding the mechanism of action of modulator compounds for the cystic fibrosis transmembrane conductance regulator (CFTR) is key for the optimization of therapeutics as well as obtaining ...insights into the molecular mechanisms of CFTR function. We demonstrate the direct binding of VX-809 to the first nucleotide-binding domain (NBD1) of human CFTR. Disruption of the interaction between C-terminal helices and the NBD1 core upon VX-809 binding is observed from chemical shift changes in the NMR spectra of residues in the helices and on the surface of
-strands S3, S9, and S10. Binding to VX-809 leads to a significant negative shift in NBD1 thermal melting temperature (T
), pointing to direct VX-809 interaction shifting the NBD1 conformational equilibrium. An inter-residue correlation analysis of the chemical shift changes provides evidence of allosteric coupling between the direct binding site and the NBD1:CL4 interface, thus enabling effects on the interface in the absence of direct binding in that location. These NMR binding data and the negative T
shifts are very similar to those previously reported by us for binding of the dual corrector-potentiator CFFT-001 to NBD1 (Hudson et al., 2012), suggesting that the two compounds may share some aspects of their mechanisms of action. Although previous studies have shown an important role for VX-809 in modulating the conformation of the first membrane spanning domain (Aleksandrov et al., 2012; Ren et al., 2013), this additional mode of VX-809 binding provides insight into conformational dynamics and allostery within CFTR.
First Resolution of Microlensed Images Dong, Subo; Mérand, A.; Delplancke-Ströbele, F. ...
Astrophysical journal/The Astrophysical journal,
01/2019, Letnik:
871, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
We employ Very Large Telescope Interferometer GRAVITY to resolve, for the first time, the two images generated by a gravitational microlens. The measurements of the image separation
mas, and ...hence the Einstein radius
θ
E
= 1.87 ± 0.03 mas, are precise. This demonstrates the robustness of the method, provided that the source is bright enough for GRAVITY (
K
≲ 10.5) and the image separation is of order of or larger than the fringe spacing. When
θ
E
is combined with a measurement of the “microlens parallax”
, the two will together yield the lens mass and lens–source relative parallax and proper motion. Because the source parallax and proper motion are well measured by
Gaia
, this means that the lens characteristics will be fully determined, whether or not it proves to be luminous. This method can be a powerful probe of dark, isolated objects, which are otherwise quite difficult to identify, much less characterize. Our measurement contradicts Einstein’s prediction that “the luminous circle i.e., microlensed image cannot be distinguished” from a star.
There are an increasing number of wound closure materials and suturing techniques described in the dermatologic and surgery literature. A dermatologic surgeon's familiarity with these materials and ...techniques is important to supplement his or her already established practices and improve surgical outcomes.
To perform a thorough literature review of wound closure materials (sutures, tissue adhesives, surgical tape, and staples) and suturing techniques and to outline how and when to use them.
A literature review was conducted using PubMed and other online search engines. Keywords searched included suture, tissue adhesive, tissue glue, surgical tape, staples, dermatologic suturing, and suturing techniques.
Numerous articles outline the utility of various sutures, surgical adhesives, surgical tape, and staples in dermatologic surgery. In addition, there are various articles describing classic and novel suturing techniques along with their specific uses in cutaneous surgery.
Numerous factors must be considered when choosing a wound closure material and suturing technique. These include wound tension, desire for wound edge eversion/inversion, desired hemostasis, repair type, patient's ability to care for the wound and return for suture removal, skin integrity, and wound location. Careful consideration of these factors and proper execution of suturing techniques can lead to excellent cosmetic results.
To determine the effect of bovine lactoferrin on prevention of late-onset sepsis (LOS) and neurodevelopment delay.
Randomized, double-blind, controlled trial in neonates with a birth weight of ...500-2000 g in 3 neonatal units in Lima, Peru, comparing bovine lactoferrin 200 mg/kg/day with placebo administered for 8 weeks. The primary outcome was the first episode of culture-proven LOS or sepsis-associated death. Neurodevelopment delay was assessed by the Mullen Scales at 24 months corrected age.
Of the 414 infants enrolled, 209 received bovine lactoferrin and 205 received placebo. LOS or sepsis-associated death occurred in 22 infants (10.5%) in the bovine lactoferrin group vs 30 (14.6%) in the placebo group; there was no difference after adjusting for hospital and birth weight; hazard ratio 0.73 (95% CI, 0.42-1.26). For infants with birth weights of <1500 g the hazard ratio was 0.69 (95% CI, 0.39-1.25). The mean age-adjusted normalized Mullen composite score at 24 months was 83.3 ± 13.6 in the bovine lactoferrin group vs 82.6 ± 13.1 in the placebo group. Growth outcomes and rehospitalization rates during the 2-year follow-up were similar in both groups, except for significantly less bronchiolitis in the bovine lactoferrin group (rate ratio, 0.34; 95% CI, 0.14-0.86).
Supplementation with bovine lactoferrin did not decrease the incidence of sepsis in infants with birth weights of <2000 g. Growth and neurodevelopment outcomes at 24 months of age were similar. Neonatal bovine lactoferrin supplementation had no adverse effects.
ClinicalTrials.gov: NCT01525316.
Differential scanning calorimetry (DSC) detects protein thermal unfolding by directly measuring the heat absorbed. Simple DSC experiments that require relatively small amounts of pure material can ...provide a wealth of information related to structure, especially with respect to domain architecture, without the need for a complete thermodynamic analysis. Thus, DSC is an ideal additional tool for membrane protein characterization and also offers several advantages over indirect thermal unfolding methods. Integral membrane proteins (IMPs) that comprise both large multitopic transmembrane domains (TMDs) and extramembranous domains (EMDs) are differentially affected by detergent interactions with both domains. In fact, in some cases, destabilization of the EMD by detergent may dominate overall IMP stability. This chapter will (1) provide a perspective on the advantages of DSC for membrane protein characterization and stability measurements, including numerous examples spanning decades of research; (2) introduce models for the interaction and destabilization of IMPs by detergents; (3) discuss two case studies from the authors' lab; and (4) offer practical advice for performing DSC in the presence of detergents.
To determine the incidence and prognosis of peripartum cardiomyopathy (PPCM) in rural Haiti.
Prospectively identified patients with PPCM treated at the Hospital Albert Schweitzer (HAS), Deschapelles, ...Haiti, were included in this study. Patients who presented to HAS from February 1, 2000, to January 31, 2005, were identified through a search of the HAS PPCM Registry. Clinical and serial echocardiographic data were collected on these patients.
The 5-year experience confirms the high incidence of PPCM in this area, approximately 1 case per 300 live births, which is severalfold the estimated incidence in the United States (estimated 1 case per 3000 to 4000 live births). In this population, the ratio of PPCM deaths for the 5-year period was 47.1 per 100,000 births compared with the US ratio of 0.62 per 100,000 births. The mortality rate was 15.3% (15 deaths of 98 patients), and the mean follow-up was 2.2 years (range, 1 month to 5 years). Five years after the initiation of the HAS PPCM Registry search, 26 (28%) of 92 patients with PPCM observed for at least 6 months had regained normal left ventricular function. The difference in left ventricular echocardiographic features at diagnosis between deceased patients and survivors was not statistically significant: mean end-diastolic dimension (6.2 vs 5.8 cm;
P=.08), ejection fraction (22% vs 25%;
P=.12), and fractional shortening (16% vs 15%;
P=.46). Left ventricular echocardiographic features at diagnosis were unable to predict individually who would eventually recover, although a statistically significant difference occurred at diagnosis between the recovered group and nonrecovered group for mean ejection fraction (28% vs 23%;
P<.001) and fractional shortening (17% vs 14%;
P=.004).
Peripartum cardiomyopathy occurs significantly more commonly in rural Haiti on a per capita basis than in the United States. Patients with PPCM have a higher mortality rate and a poorer return of normal ventricular function.
Lactoferrin (LF) is a breast milk glycoprotein with antimicrobial and anti-inflammatory effects. Its beneficial properties in infants, especially in those born preterm, are currently being studied in ...clinical trials. However, the maternal and nursing infant factors that may affect LF concentration in breast milk are still not clear. We conducted a systematic review to investigate the factors that may affect the concentration of LF in breast milk. We used a 2-step approach to identify the eligible studies according to inclusion/exclusion criteria, and to determine which studies would be considered. We included 70 qualified articles from 29 countries with publication dates ranging from 1976 to 2015. We described the correlation between LF concentration in breast milk and lactation stage; 10 maternal factors, such as race, parity, among others; and 2 infant factors: infections and prematurity. Colostrum has the highest LF levels, but they decrease with days postpartum. No other factor has been consistently associated with LF concentration. A major limitation of the majority of the published studies is the small sample size and the different methods used to measure LF concentration. Therefore, there is a need for large, multicenter studies with standardized study design, sample collection, and LF measurement methods to identify clinically significant factors associated with LF expression in breast milk, which will help promote exclusive breastfeeding in preterm infants.
Structural and biochemical studies of mammalian membrane proteins remain hampered by inefficient production of pure protein. We explored codon optimization based on highly expressed Pichia pastoris ...genes to enhance co-translational folding and production of P-glycoprotein (Pgp), an ATP-dependent drug efflux pump involved in multidrug resistance of cancers.
Codon-optimized "Opti-Pgp" and wild-type Pgp, identical in primary protein sequence, were rigorously analyzed for differences in function or solution structure. Yeast expression levels and yield of purified protein from P. pastoris (∼130 mg per kg cells) were about three-fold higher for Opti-Pgp than for wild-type protein. Opti-Pgp conveyed full in vivo drug resistance against multiple anticancer and fungicidal drugs. ATP hydrolysis by purified Opti-Pgp was strongly stimulated ∼15-fold by verapamil and inhibited by cyclosporine A with binding constants of 4.2±2.2 µM and 1.1±0.26 µM, indistinguishable from wild-type Pgp. Maximum turnover number was 2.1±0.28 µmol/min/mg and was enhanced by 1.2-fold over wild-type Pgp, likely due to higher purity of Opti-Pgp preparations. Analysis of purified wild-type and Opti-Pgp by CD, DSC and limited proteolysis suggested similar secondary and ternary structure. Addition of lipid increased the thermal stability from T(m) ∼40 °C to 49 °C, and the total unfolding enthalpy. The increase in folded state may account for the increase in drug-stimulated ATPase activity seen in presence of lipids.
The significantly higher yields of protein in the native folded state, higher purity and improved function establish the value of our gene optimization approach, and provide a basis to improve production of other membrane proteins.
We report the lens mass and distance measurements of the nearby microlensing event TCP J05074264+2447555 (Kojima-1). We measure the microlens parallax vector using Spitzer and ground-based light ...curves with constraints on the direction of lens-source relative proper motion derived from Very Large Telescope Interferometer (VLTI) GRAVITY observations. Combining this determination with the angular Einstein radius measured by VLTI-GRAVITY observations, we find that the lens is a star with mass at a distance DL = 429 21 pc. We find that the blended light basically all comes from the lens. The lens-source proper motion is , so with currently available adaptive-optics instruments, the lens and source can be resolved in 2021. This is the first microlensing event whose lens mass is unambiguously measured by interferometry + satellite-parallax observations, which opens a new window for mass measurements of isolated objects such as stellar-mass black holes.
The O-Z flap has traditionally been used for surgical defects adjacent to critical anatomic structures requiring a repair option that minimizes distortion and functional impairment. However, another ...advantage of the O-Z flap is that it is tissue conservative, particularly in comparison to primary closure. In fact, the design simply takes the Burow's triangles that would be discarded and rotates them inward.
The purpose of this work is to detail the type of post-Mohs defects, which might benefit from consideration of the O-Z flap with emphasis on tissue conservation and restoration of contour to the surgical site. Furthermore, the authors wish to describe unique considerations in each location and methods to appropriately plan the O-Z flap in each circumstance.
The authors reviewed all flaps classified as O-Z in their tumor registry. The approximate size of the defect reconstructed, complications, and long-term outcomes were recorded.
O-Z flap implementation is described in detail for repair of defects located at the lateral nasal tip, nose-cheek junction, medial canthus, and mid-cheek.
The O-Z flap can be effectively used to repair defects located at the lateral nasal tip, nose-cheek junction, medial canthus, and mid-cheek. It is a mechanically simple flap with predictable tension vectors, which can be specifically oriented to protect the free margin.
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