Vaccines against the original strain of SARS-CoV-2 provide T cell memory to the B.1.1.529 variant.

BACKGROUND: The SARS-CoV-2 variant B.1.1.529 potentially escapes immunity from vaccination via a heavily mutated Spike protein. Here, we analyzed whether T cell memory towards the B.1.1.529 Spike protein is present in individuals who received two or three doses of vaccines designed against the original Wuhan strain of SARS-CoV-2. METHODS: PBMCs were isolated from two- and three-times vaccinated study participants and incubated in vitro with peptide pools of the Spike protein derived from sequences of the original Wuhan or the B.1.1.529 strains of SARS-CoV-2. Activated antigen-specific T cells were detected by flow cytometry. In silico analyses with NetMHCpan and NetMHCIIpan were used to determine differences in MHC class presentation between the original strain and the B.1.1.529 strain for the most common MHCs in the European-Caucasian population. RESULTS: Here we show, that both CD4 and CD8 responses to the B.1.1.529 Spike protein are marginally reduced compared to the ancestor protein and a robust T cell response is maintained. Epitope analyses reveal minor differences between the two SARS-CoV-2 strains in terms of MHC class presentations for the MHC-alleles being most common in the European-Caucasian population. CONCLUSIONS: The memory T cell response induced via first generation vaccination remains robust and is mostly unaffected by B.1.1.529 mutations. Correspondingly, in silico analyses of MHC presentation of epitopes derived from the B.1.1.529 Spike protein shows marginal differences compared to the ancestral SARS-CoV-2 strain.

Vaccination against SARS-CoV-2 results in the production of proteins called antibodies, that bind and inactivate the virus, and cells that help to eliminate it from the body in a future encounter, such as memory T cells. Both antibodies and memory T cells remain in the body after vaccination with memory T cells being present for longer than antibodies. Here, we determined that even though most of the first generation vaccines were created to prevent infection with the original SARS-CoV-2 virus, the memory T cells generated by this vaccination can also detect the omicron variant.

Correction: Operative treatment of fragility fractures of the pelvis is connected with lower mortality. A single institution experience.

[This corrects the article DOI: 10.1371/journal.pone.0253408.].

Operative treatment of fragility fractures of the pelvis is connected with lower mortality. A single institution experience.

BACKGROUND: Fragility fractures of the pelvis (FFP) represent an increasing clinical entity. Until today, there are no guidelines for treatment of FFP. In our center, recommendation for operative treatment was given to all patients, who suffered an FFP type III and IV and to patients with an FFP type IIwith unsuccessful non-operative treatment. We performed a retrospective observational study and investigated differences between fracture classes and management alternatives. We hypothetized that operative treatment may reduce mortality. MATERIALS AND METHODS: The medical charts and radiographs of 362 patients were analysed. Patient demographics, FFP-classification, length of hospital stay (LoS), type of treatment, general and surgery-related complications, mortality, Short Form-8 physical component score (SF-8 PCS) and mental component score (SF-8 MCS), Parker Mobility Score (PMS) and Numeric Rating Scale (NRS) were documented. RESULTS: 238 patients had FFP type II and 124 FFP type III and IV. 52 patients with FFP type II (21.8%) and 86 patients with FFP type III and IV (69.4%) were treated operatively (p<0.001). Overall mortality did not differ between the fracture classes (p = 0.127) but was significantly lower in the operative group (p<0.001). Median LoS was significantly higher in FFP type III and IV (p<0.001) and in operated patients (p<0.001). There were more in-hospital complications in patients with FFP type III and IV (p = 0.001) and in the operative group (p = 0.006). More patients of the non-operative group were mobile (p<0.001) and independent (p<0.001) at discharge. Half of the patients could not return in their living environment.203 of the 235 surviving patients (86%) answered the questionnaires after a mean follow-up time of 38 months. SF-8 PCS, SF-8 MCS and PMS did not differ between the fracture classes and treatment groups. Pain perception was higher in the operated group (p = 0.013). CONCLUSION: In our study, we observed that operative treatment of FFP provides low mortality rates, although LoS and in-hospital complications were higher in the operative group. At discharge, the non-operative group was more mobile and independent. At follow up, quality of life and mobility were comparable between the groups. Further prospective studies are needed to clarify the impact of operative treatment of FFP on mortality and functional outcome.

Trans-sacral bar osteosynthesis provides low mortality and high mobility in patients with fragility fractures of the pelvis.

Operative treatment of osteoporosis-associated fragility fractures of the pelvis (FFP) and the sacrum is advocated with immobilizing or longstanding pain, fracture progression and displacement. We analyzed clinical outcomes regarding mobility, quality of life, and mortality of patients with FFP treated with trans-sacral bar (TB) osteosynthesis through S1. Demographics, clinical data, and operation-related data of patients with an FFP treated with TB were acquired from chart review. We assessed mortality, quality of life (EQ-5D), mobility, and residential status at follow-up. Seventy-nine females and six males with a median age of 78.0 years (IQR 73-84) were included, median follow-up was 3.2 years. Medical complications during hospitalization occurred in 28%. Operative revision was carried out in 15% of patients. One-year survival was 90.4%, this was associated with shorter preoperative and total length of stay in hospital (p 0.006 and 0.025, respectively). At follow-up, 85% lived at home and 82% walked with or without walking aid. Higher EQ-5D was reached with higher mobility status and living at home (p < 0.001 and < 0.001, respectively). TB osteosynthesis is an adequate and reliable method for fixation of FFP in the posterior pelvic ring to ensure timely mobilization. Shorter preoperative and total length of stay had lower mortality rates, advocating a standardized management protocol to limit time delay to operative therapy. Patients treated with TB osteosynthesis had low 1-year mortality of less than 10%.

Electrospray Synthesis of Poly(lactide-co-glycolide) Nanoparticles Encapsulating Peptides to Enhance Proliferation of Antigen-Specific CD8+ T Cells.

Polymer nanoparticles (NP) are of escalating interest for their application as immune stimulatory pharmaceutics. The production of nanosized carrier systems is currently being widely investigated, but commonly used techniques, such as the double emulsion technique, are limited by shortcomings of low encapsulation efficiency and poor control over size distribution. In this study, the electrospray technique was successfully implemented and optimized to produce monodisperse 200-nm poly(lactide-co-glycolide) (PLGA) NP. For cytomegalovirus (CMV) pp65 and IE-1 peptides, a consistent encapsulation efficiency of approximately 85% was achieved. In vitro stimulation of peripheral blood mononuclear cells (PBMCs) from CMV+ donors using electrosprayed pp65489-503 peptide-loaded NP revealed a significantly increased proliferation rate and frequency of antigen-specific CD8+ T cells as compared to the soluble peptide. The results of this study demonstrate the suitability of the electrospray technique for production of monodisperse PLGA NP with high drug encapsulation efficiency as promising peptide-based vaccine carriers.

Poly(3-hydroxybutyrate) (PHB) patches for covering anterior skull base defects - an animal study with minipigs.

CONCLUSION: We conclude that PHB patch material may fulfil the specific requirements that are necessary for a dural substitute, including defect closure, stability and biocompatibility. Our results support the assumed positive influence of PHB on bone regeneration. OBJECTIVES: Although many experimental and clinical studies have been performed to identify a suitable material to repair defects of the dura mater, no ideal dural substitute is currently available. PHB is a biodegradable and biocompatible polymer that might serve as dural substitute and osteosynthesis material in cranial bone defects. MATERIALS AND METHODS: Different standardized PHB patches were used in six minipigs for covering defined bone defects in the anterior skull base including a dura mater lesion as well as in the frontal sinus front wall. After a defined time of implantation of 3, 6, and 9 months PHB patches were explanted and examined for clinical findings, biodegradation, presence of microorganisms, histological findings, and electron microscopy. RESULTS: The examinations revealed an increasing closure of bone defect corresponding with time. The anterior skull base bone defect was completely closed after 9 months. The histological findings revealed a connective tissue and callus formation around the PHB patches with fibroblasts and foreign body/giant cell reaction growing through PHB membrane pores. There were no reactions or adhesions between brain and PHB or dura mater and PHB, respectively. Investigations of biodegradation and electron microscopy revealed a continuous breakdown of PHB in the course of time with variations due to different PHB structures. Microbiological investigations could not detect any florid intracranial infection.

In vitro study of drug-eluting stent coatings based on poly(L-lactide) incorporating cyclosporine A - drug release, polymer degradation and mechanical integrity.

In this study, absorbable polymer stent coatings for localized drug delivery based on poly(L-lactide) (PLLA) and cyclosporine A (CsA) were developed and tested in vitro. Metallic stents were coated with different compositions of PLLA/CsA (70/30, 60/40, 50/50% w/w) and beta-sterilized. The specimens were used to assess the drug release kinetics with HPLC. Sterilization influenced polymer degradation was measured with GPC. Mechanical integrity of the stent coatings was studied with SEM. The interconnection of the coated stents with a balloon-catheter was characterized by the measurement of stent dislodgment force. A migration assay was used to determine the inhibitory effect of the model drug CsA on smooth muscle cell (SMC) migration. The release of CsA was established over time periods up to 24 days in sodium chloride solution and in porcine blood plasma. An inhibition of SMC migration (max. 26-33%) was found for CsA concentrations of 4 x 10(-5) to 4 x 10(-7) mol/l. Marked molecular weight reduction (70-80%) of the PLLA matrix occurred after beta-sterilization. We also observed a substantial decrease of in vitro degradation time. The maintenance of the mechanical integrity of the polymer coating during crimping and dilation of the specimens could be verified, and a sufficient stent dislodgment force of 0.8-0.9 N was measured.

In vitro and in vivo studies on blends of isotactic and atactic poly (3-hydroxybutyrate) for development of a dura substitute material.

Blends of semicrystalline isotactic poly(3-hydroxybutyrate) (PHB) with amorphous atactic PHB (at-PHB) were prepared by solution-casting using 30%, 50% and 70% at-PHB, and were studied for medical applications. The mechanical properties of the blends including the elastic modulus and elongation at break are strongly affected by the blend composition. The elastic modulus decreases with increasing fraction of at-PHB in the blend from 3350 MPa in the case of PHB to 170 MPa of PHB/at-PHB (30/70). In contrast, the elongation at break increases from 2% in pure PHB up to 50% in the case of the blend with 70% at-PHB. The in vitro degradation is changed as well. The molecular weight of PHB/at-PHB (30/70) is reduced to 5% after 2 years storage in phosphate buffer compared to 35% for pure PHB stored at identical conditions. The in vitro cell vitality is slightly reduced depending on the composition. PHB/at-PHB blends with 30% and 50% at-PHB were selected as dura substitute in minipigs based on the results of the in vitro investigation and the mechanical testing. Patch films with a structured surface on one side were fabricated by a dipping-leaching method. Dura defects were clinically and histologically examined 3, 6, and 9 months after implantation, confirming defect closure, prevention of adhesions to brain tissue, and no signs of inflammation or malignant degeneration. The PHB-based patch materials fulfill the requirements which are necessary for a dura substitute.

Mechanical properties of laser cut poly(L-lactide) micro-specimens: implications for stent design, manufacture, and sterilization.

BACKGROUND: The development of endoluminal stents from polymeric materials requires an understanding of the basic mechanical properties of the polymer and the effects of manufacturing and sterilization on those properties. METHODS: Pure poly(L-lactide) (PLLA) and PLLA containing varying amounts of triethylcitrate (TEC) as a plasticizer (5-10-15%) were studied. The specimens were solution-cast and CO2 laser-cut. Specimen dimensions were adapted to the strut size of polymeric vascular stents. The properties of the PLLA micro-specimens were assessed before and after sterilization (EtO cold gas, H2O2-plasma, beta- and gamma-irradiation). Tensile tests, and creep and recovery tests were carried out at 37 degrees C. Additionally the thermal and thermo-mechanical characteristics were investigated using dynamic-mechanical analysis (DMA) and differential scanning calorimetry (DSC). RESULTS: The results showed the dramatic influence of the plasticizer content and sterilization procedure on the mechanical properties of the material. Laser cutting had a lesser effect. Hence the effects of processing and sterilization must not be overlooked in the material selection and design phases of the development process leading to clinical use. Altogether, the results of these studies provide a clearer understanding of the complex interaction between the laser machining process and terminal sterilization on the primary mechanical properties of PLLA and PLLA plasticized with TEC.

In vitro and in vivo degradation studies for development of a biodegradable patch based on poly(3-hydroxybutyrate).

For the development of a resorbable gastrointestinal patch, the in vitro degradation of solution-cast films of poly(3-hydroxybutyrate) (PHB), modifications of PHB expected to influence its degradation time, as well a poly(L-lactide) (PLLA) was examined. The molecular weight of pure PHB decreased by one-half after 1 year in buffer solution (pH 7.4, 37 degrees C). Acceleration in molecular weight decrease was observed by blending with atactic PHB, whereas no influence was found with low-molecular weight PHB. Leaching of a water-soluble additive led to a slight acceleration of PHB degradability. In contrast, a deceleration in degradation rate was observed with the addition of a hydrophobic plasticizer. In vitro tests indicated an accelerating effect of pancreatin on PHB degradation, whereas PLLA degradation remained essentially uninfluenced. In comparison to simple hydrolysis, the degradation rate of PHB was accelerated about threefold. From the in vitro results, a PHB/atactic PHB blend was selected for repair of a bowel defect in Wistar rats. A patch film was fabricated by a dipping/leaching method. Twenty-six weeks post-implantation, material remnants were found in only one of four animals. The bowel defects were closed in all cases. It could be assessed that the patch material resists the intestinal secretions for a sufficiently long time but that it finally degrades completely.

Anti-inflammatory prodrugs as plasticizers for biodegradable implant materials based on poly(3-hydroxybutyrate).

Salicylic and acetylsalicylic acid esters were tested as plasticizers for biodegradable poly(3-hydroxybutyrate) (PHB). The aim is the combination of plasticizing and anti-inflammatory properties in the fabrication of implant materials. Solution-cast films made of mixtures of PHB and 30% ester showed plasticization accompanied by a decrease of elastic modulus and an increase in elongation at break in comparison with pure PHB films. However, the number of usable plasticizers from the group of the salicylic acid and acetylsalicylic acid esters is limited. Short-chain derivatives are volatile while long-chain compounds tend to crystallize. In both cases PHB films embrittle within short time. Moreover, some derivatives show a fast release in an aqueous environment. As alternative nonsteroidal anti-inflammatory prodrugs arylpropionic acid esters were tested as plasticizers. The addition of ketoprofen ethyl ester led to PHB films with decreased brittleness. In summary, various esters of anti-inflammatory drugs show plasticizing effects on solution-cast PHB films comparable with those of commonly used citric acid esters.