Rectourethral fistula (RUF) is an infrequent but severe complication of the treatment of prostate cancer. Herein, we describe a new surgical approach used successfully in 3 patients that incorporates ...a partially de-epithelialized mid-perineal scrotal flap (MPSF), used as interposition flap, that can be used in almost every patient with RUF after radiotherapy, regardless of having or not a concomitant posterior urethra or bladder neck stricture or contracture that might require a simultaneous urethroplasty. The interposition flap includes well vascularized subcutaneous fat tissue by distal vascular branches of the internal pudendal vessels that reaches without tension the deep perineum up to the posterior bladder neck. The MPSF is a time efficient procedure that allows excellent access to the bulbar urethra and to the surgical plane between rectum and prostate and it does not require a separate incision for the flap harvesting procedure when required.
Online grocery shopping in Germany has shown a strong growth in the past years and is expected to further develop in the future, especially through the influence of COVID-19. The main purpose of this ...study was to examine six theoretical customer-oriented factors and their influence on consumer online grocery purchase intentions. Additionally, this study compares consumer perceptions before and since the COVID-19 outbreak. Since the health crisis is very recent, the research on its impact on online grocery purchasing behavior is limited. A total of 402 valid questionnaires were collected in Germany. The data were analyzed using the software SPSS IBM 28. The results indicate that perceived risk still has a negative influence on purchase intentions, thus remaining relevant in online grocery shopping. However, the consumers’ perceived risk is considered lower compared to the pre-COVID-19 scenario. Moreover, perceived usefulness, perceived ease of use, perceived trust, convenience, as well as situational factors were found to have a positive relationship with purchase intention, both before the COVID-19 crisis and since then. The COVID-19 pandemic shows a strong reduction in perceived risk, while the remaining characteristics increase at moderate levels. Online grocery businesses could use the insights of this study to reduce perceived risks as well as successfully communicate the benefits of online shopping to consumers.
The receptor‐binding domain (RBD) of the SARS‐CoV‐2 spike protein is a candidate vaccine antigen that binds angiotensin‐converting enzyme 2 (ACE2), leading to virus entry. Here, it is shown that ...rapid conversion of recombinant RBD into particulate form via admixing with liposomes containing cobalt‐porphyrin‐phospholipid (CoPoP) potently enhances the functional antibody response. Antigen binding via His‐tag insertion into the CoPoP bilayer results in a serum‐stable and conformationally intact display of the RBD on the liposome surface. Compared to other vaccine formulations, immunization using CoPoP liposomes admixed with recombinant RBD induces multiple orders of magnitude higher levels of antibody titers in mice that neutralize pseudovirus cell entry, block RBD interaction with ACE2, and inhibit live virus replication. Enhanced immunogenicity can be accounted for by greater RBD uptake into antigen‐presenting cells in particulate form and improved immune cell infiltration in draining lymph nodes. QS‐21 inclusion in the liposomes results in an enhanced antigen‐specific polyfunctional T cell response. In mice, high dose immunization results in minimal local reactogenicity, is well‐tolerated, and does not elevate serum cobalt levels. Taken together, these results confirm that particulate presentation strategies for the RBD immunogen should be considered for inducing strongly neutralizing antibody responses against SARS‐CoV‐2.
The receptor‐binding domain (RBD) of SARS‐CoV‐2 is a target for COVID‐19 vaccine development. Using a next‐generation vaccine adjuvant system that rapidly converts soluble antigens into stable particles, the neutralizing antibody response induced by the RBD is greatly enhanced, demonstrating merit for particle‐based approaches toward RBD‐based vaccines.
ATP hydrolysis is required for the synthesis, transport and polymerization of monomers for macromolecules as well as for the assembly of the latter into cellular structures. Other cellular processes ...not directly related to synthesis of biomass, such as maintenance of membrane potential and cellular shape, also require ATP. The unicellular flagellated parasite Trypanosoma brucei has a complex digenetic life cycle. The primary energy source for this parasite in its bloodstream form (BSF) is glucose, which is abundant in the host's bloodstream. Here, we made a detailed estimation of the energy budget during the BSF cell cycle. As glycolysis is the source of most produced ATP, we calculated that a single parasite produces 6.0 x 1011 molecules of ATP/cell cycle. Total biomass production (which involves biomass maintenance and duplication) accounts for ~63% of the total energy budget, while the total biomass duplication accounts for the remaining ~37% of the ATP consumption, with in both cases translation being the most expensive process. These values allowed us to estimate a theoretical YATP of 10.1 (g biomass)/mole ATP and a theoretical Formula: see text of 28.6 (g biomass)/mole ATP. Flagellar motility, variant surface glycoprotein recycling, transport and maintenance of transmembrane potential account for less than 30% of the consumed ATP. Finally, there is still ~5.5% available in the budget that is being used for other cellular processes of as yet unknown cost. These data put a new perspective on the assumptions about the relative energetic weight of the processes a BSF trypanosome undergoes during its cell cycle.
The ongoing coronavirus disease 2019 (COVID‐19) pandemic, caused by severe acute respiratory coronavirus 2 (SARS‐CoV‐2), has killed untold millions worldwide and has hurtled vaccines into the ...spotlight as a go‐to approach to mitigate it. Advances in virology, genomics, structural biology, and vaccine technologies have enabled a rapid and unprecedented rollout of COVID‐19 vaccines, although much of the developing world remains unvaccinated. Several new vaccine platforms have been developed or deployed against SARS‐CoV‐2, with most targeting the large viral Spike immunogen. Those that safely induce strong and durable antibody responses at low dosages are advantageous, as well are those that can be rapidly produced at a large scale. Virtually all COVID‐19 vaccines and adjuvants possess nanoscale or microscale dimensions and represent diverse and unique biomaterials. Viral vector vaccine platforms, lipid nanoparticle mRNA vaccines and multimeric display technologies for subunit vaccines have received much attention. Nanoscale vaccine adjuvants have also been used in combination with other vaccines. To deal with the ongoing pandemic, and to be ready for potential future ones, advanced vaccine technologies will continue to be developed in the near future. Herein, the recent use of advanced materials used for developing COVID‐19 vaccines is summarized.
Vaccines have been a major focus of the global SARS‐CoV‐2 response. Advanced materials have played a role in enabling the current generation of effective vaccines that have been deployed, and also they have shown promise in next‐generation vaccines that are being developed in response to the pandemic.
Bacterial multidrug efflux pumps are antibiotic resistance determinants present in all microorganisms. With few exceptions, they are chromosomally encoded and present a conserved organization both at ...the genetic and at the protein levels. In addition, most, if not all, strains of a given bacterial species present the same chromosomally-encoded efflux pumps. Altogether this indicates that multidrug efflux pumps are ancient elements encoded in bacterial genomes long before the recent use of antibiotics for human and animal therapy. In this regard, it is worth mentioning that efflux pumps can extrude a wide range of substrates that include, besides antibiotics, heavy metals, organic pollutants, plant-produced compounds, quorum sensing signals or bacterial metabolites, among others. In the current review, we present information on the different functions that multidrug efflux pumps may have for the bacterial behaviour in different habitats as well as on their regulation by specific signals. Since, in addition to their function in non-clinical ecosystems, multidrug efflux pumps contribute to intrinsic, acquired, and phenotypic resistance of bacterial pathogens, the review also presents information on the search for inhibitors of multidrug efflux pumps, which are currently under development, in the aim of increasing the susceptibility of bacterial pathogens to antibiotics.
The development of synthetic anion transporters is motivated by their potential application as treatment for diseases that originate from deficient anion transport by natural proteins. Transport of ...bicarbonate is important for crucial biological functions such as respiration and digestion. Despite this biological relevance, bicarbonate transport has not been as widely studied as chloride transport. Herein we present an overview of the synthetic receptors that have been studied as bicarbonate transporters, together with the different assays used to perform transport studies in large unilamellar vesicles. We highlight the most active transporters and comment on the nature of the functional groups present in active and inactive compounds. We also address recent mechanistic studies that have revealed different processes that can lead to net transport of bicarbonate, as well as studies reported in cells and tissues, and comment on the key challenges for the further development of bicarbonate transporters.
The development of synthetic compounds for the transmembrane transport of bicarbonate is discussed in this Review, presenting the structures of the different transporters and the methods to study the transport process in liposomal membranes, together with the most recent studies on transport mechanism and biological activity in cells and tissues.
Cystathionine β-synthase (CBS) catalyzes the condensation of l-serine and l-homocysteine to give l-cystathionine in the transsulfuration pathway. Recently, a few O-acetylserine (l-OAS)-dependent CBSs ...(OCBSs) have been found in bacteria that can exclusively function with l-OAS. CBS from Toxoplasma gondii (TgCBS) can efficiently use both l-serine and l-OAS to form l-cystathionine. In this work, a series of site-specific variants substituting S84, Y160, and Y246 with hydrophobic residues found at the same positions in OCBSs was generated to explore the roles of the hydroxyl moieties of these residues as determinants of l-serine/l-OAS preference in TgCBS. We found that the S84A/Y160F/Y246V triple mutant behaved like an OCBS in terms of both substrate requirements, showing β-replacement activity only with l-OAS, and pH optimum, which is decreased by ~1 pH unit. Formation of a stable aminoacrylate upon reaction with l-serine is prevented by the triple mutation, indicating the importance of the H-bonds between the hydroxyl groups of Y160, Y246, and S84 with l-serine in formation of the intermediate. Analysis of the independent effect of each mutation on TgCBS activity and investigation of the protein-aminoacrylate complex structure allowed for the conclusion that the hydroxyl group of Y246 has a major, but not exclusive, role in controlling the l-serine preference by efficiently stabilizing its leaving group. These studies demonstrate that differences in substrate specificity of CBSs are controlled by natural variations in as few as three residue positions. A better understanding of substrate specificity in TgCBS will facilitate the design of new antimicrobial compounds.
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