Functional peptide presentation on different hydrogen bonding biomaterials using supramolecular additives

Supramolecular biomaterials based on hydrogen bonding units can be conveniently functionalized in a mix-and-match approach using supramolecular additives. The presentation of bioactive additives has been sparsely investigated in supramolecular-based elastomeric biomaterials. Here it was investigated how cell adhesive peptides are presented and affect the surface in supramolecular biomaterials based either on ureido-pyrimidinone (UPy) or bisurea (BU) moieties. Polycaprolactone modified with UPy or BU moieties served as the base material. RGD or cyclic (c)RGD were conjugated to complementary supramolecular motifs, and were mixed with the corresponding base materials as supramolecular additives. Biomaterial surface morphology changed upon bioactivation, resulting in the formation of random aggregates on UPy-based materials, and fibrous aggregates on BU-materials. Moreover, peptide type affected aggregation morphology, in which RGD led to larger cluster formation than cRGD. Increased cRGD concentrations led to reduced focal adhesion size and cell migration velocity, and increased focal adhesion numbers in both systems, yet most prominent on functionalized BU-biomaterials. In conclusion, both systems exhibited distinct peptide presenting properties, of which the BU-system most strongly affected cellular adhesive behavior on the biomaterial. This research provided deeper insights in the differences between supramolecular elastomeric platforms, and the level of peptide introduction for biomaterial applications.

Antimicrobial peptide modification of biomaterials using supramolecular additives

Biomaterials based on non-active polymers functionalized with antimicrobial agents by covalent modification or mixing are currently regarded as high potential solutions to prevent biomaterial associated infections that are major causes of biomedical device failure. Herewith a strategy is proposed in which antimicrobial materials are prepared by simply mixing-and-matching of ureido-pyrimidinone (UPy) based supramolecular polymers with antimicrobial peptides (AMPs) modified with the same UPy-moiety. The N-terminus of the AMPs was coupled in solution to an UPy-carboxylic acid synthon resulting in formation of a new amidic bond. The UPy-functionalization of the AMPs did not affect their secondary structure, as proved by circular dichroism spectroscopy. The antimicrobial activity of the UPy-AMPs in solution was also retained. In addition, the incorporation of UPy-AMPs into an UPy-polymer was stable and the final material was biocompatible. The addition of 4 mol % of UPy-AMPs in the UPy-polymer material protected against colonization by Escherichia coli, and methicillin-sensitive and -resistant strains of Staphylococcus aureus. This modular approach enables a stable but dynamic incorporation of the antimicrobial agents, allowing at the same time for the possibility to change the nature of the polymer, as well as the use of AMPs with different activity spectra. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1926-1934.

Dual Electrospun Supramolecular Polymer Systems for Selective Cell Migration

Dual electrospinning can be used to make multifunctional scaffolds for regenerative medicine applications. Here, two supramolecular polymers with different material properties are electrospun simultaneously to create a multifibrous mesh. Bisurea (BU)-based polycaprolactone, an elastomer providing strength to the mesh, and ureido-pyrimidinone (UPy) modified poly(ethylene glycol) (PEG), a hydrogelator, introducing the capacity to deliver compounds upon swelling. The dual spun scaffolds are modularly tuned by mixing UPyPEG hydrogelators with different polymer lengths, to control swelling of the hydrogel fiber, while maintaining the mechanical properties of the scaffold. Stromal cell derived factor 1 alpha (SDF1α) peptides are embedded in the UPyPEG fibers. The swelling and erosion of UPyPEG increase void spaces and released the SDF1α peptide. The functionalized scaffolds demonstrate preferential lymphocyte recruitment proposed to be created by a gradient formed by the released SDF1α peptide. This delivery approach offers the potential to develop multifibrous scaffolds with various functions.

(3R,3aR,6R,6aR)-Hexa-hydro-furo[3,2-b]furan-3,6-diyl dibenzoate

The title compound, C₂₀H₁₈O₆, prepared from d-mannitol by a two-step procedure, is a functionalized fused bis-tetra­hydro­furan. In the central fragment, consisting of two fused tetra­hydro­furan rings, one O atom and its two adjacent C atoms, a methyl­ene and a bridgehead C atom, are disordered over two sets of sites with an occupancy ratio of 0.735 (9):0.265 (9). In the major component, the ring containing the disordered O atom is a half-chair conformation with twisted methylene and benzoate-substituted C atoms, whereas the other ring has a half-chair or T-form conformation. In the minor component, the ring with the disordered O atom has an envelope conformation, with the O atom as the flap, and the other ring has a half-chair conformation, with the O atom and the other bridgehead CH atom being twisted. The two aromatic rings are inclined to one another by 20.00 (12)°. In the crystal, adjacent molecules are linked via C—H⋯π interactions, forming chains propagating along [010].

(3S,3aS,6R,6aR)-2-Oxohexa-hydro-furo[3,2-b]furan-3,6-diyl dibenzoate

The title compound, C₂₀H₁₆O₇, contains a cis-fused γ-lactone tetra­hydro­furan ring system functionalized with two benzo­yloxy groups. Both rings adopt an envelope conformation. The mol­ecule assumes an elongated shape and exibits non-crystallographic C₂ symmetry. The benzo­yloxy groups are almost planar [maximum deviations of 0.0491 (15) and 0.0336 (17) Å for the O atoms] and their mean planes are inclined to one another by 16.51 (4)°. The crystal packing features weak C—H⋯O inter­actions. The aryl groups of adjacent mol­ecules are parallel shifted with face-to-face contacts and a shortest inter­molecular C⋯C distance of 3.482 (4) Å.

Synthesis and biological evaluation of unprecedented ring-expanded nucleosides (RENs) containing the imidazo[4,5-d][1,2,6]oxadiazepine ring system

A small collection of ring-expanded nucleosides (RENs), containing the unprecedented bis-alkylated imidazo[4,5-d][1,2,6]oxadiazepine heterocyclic ring system, has been synthesized through a new general approach. Results of preliminary cytotoxicity tests on breast (MCF-7) and lung (A549) cancer cell lines are also reported.

Isolation of a bis-iodurated tetra-THF as a trace product from the oxidation of squalene with RuO₄ and its double ring expansion to a novel bis-THF-bis-THP compound

A novel bis-iodurated polyether compound, based on an unprecedented tetra-THF backbone, has been isolated as a trace by-product of the oxidation of squalene with the catalytic system RuO₂(cat.)/NaIO₄. The double erythro configuration of the central portion of the molecule furnishes the first indirect support of the previously postulated pathway operating in the oxidative pentacyclization of the isoprenoid substrate. A bidirectional double oxidative bis-cyclization is invoked to explain the formation of this compound. The isolated substance was successfully subjected to a double rearrangement-ring expansion to give a novel bis-THF-bis-THP compound.

Outcome of acute type A aortic dissection: single-center experience from 1998 to 2007

INTRODUCTION

Acute aortic dissection (AAD) is a serious disease of the aorta with high mortality and morbidity, which requires emergency surgical treatment in order to close the site of the dissection and direct blood flow into the true lumen. Improvements in surgical technique have led to better management of patients with reduced operative mortality, although it still remains high. The aim of this study is to evaluate early and late outcomes of the surgical treatment of acute type A aortic dissection at the hospital of Lecce between 1998 and 2007. We also aim to establish a correlation between these outcomes and pre-operative conditions, surgical procedures and location of the site of the tear.

METHODS

From 1998 to 2007, 100 patients (69 males and 31 females, average age 62.2 +/- 12.3 years, range 22-85 years) underwent surgery for acute AAD at the center. Surgical techniques included replacement of the ascending aorta (Asc Ao) with or without valve replacement (including five patients who underwent the Bentall/De Bono procedure) and replacement of the Asc Ao with or without arch or hemiarch replacement.

RESULTS

In-hospital mortality was 22%, with different results between surgery for replacement of the aorta and for aorta with valve replacement (respectively, 16% and 23%). Different mortality rates were found between the distal surgical treatments, with rates of 20.8% and 18.2% respectively between replacements of the Asc Ao and of Asc Ao with arch/hemiarch, although they were not statistically significant. A different mortality rate that was subject to the patient's preoperative condition has also been found (33.3% of mortality in patients in unstable or high-risk condition vs 13.8% in patients in stable condition). The peak reached 43.5% mortality in patients taken to the operating room while in shock or cardiac tamponade. The location of the site of the tear is another factor that distinguishes mortality rates, which are 17.8% if localized at the proximal ascending aorta and 22.2% in the aortic arch. Assessment of the outcome (10 years after surgery), has shown that four patients died several years later but for reasons unrelated to the surgery.

CONCLUSIONS

The surgery of dissection is still an intervention with a relatively high in-hospital mortality risk, and whose outcome, which has been steady in the last 20 years, can be predicted according to the preoperative condition of the patient. This underlines the need to reduce the time of diagnosis indicating immediate surgical treatment.

Lower respiratory tract infections in chronic obstructive pulmonary disease outpatients with tracheostomy and persistent colonization by P. aeruginosa

Outpatients with tracheostomy can be managed with a low risk for severe airways infections despite colonization with pathogenic bacteria. No studies have been focused on chronic obstructive pulmonary disease (COPD), a condition known for recurrent exacerbations. The aim of our study was to verify whether at follow-up in tracheostomized COPD versus other disease outpatients, persistent P. aeruginosa colonization may influence the rate and treatment of lower respiratory tract infections (LRTI) or hospital admissions. Thirty-nine outpatients were considered: 24 were affected by COPD (age 66, 54-78 years, mean, range), 15 by restrictive lung disease (RLD) (57, 41-72 years). During an 18-month follow-up the number of LRTIs were recorded. Bacterial identifications were assessed at baseline and every month for 6 months in bronchial aspirates. The number of LRTI per patient was not significantly different between COPD [37, 1(0-6)] and RLD [18, 1(0-5)], [total, median (range)]. Persistent P. aeruginosa colonized 18 COPD (75%), 12 RLD patients (86%) and was not associated with an increased number of LRTI: 1(0-6) and 1(0-2), respectively. There were no differences in the number of hospital admissions: COPD 0(0-2), RLD 1(0-1), with a significant decrease versus before tracheostomy (P < 0.001). In conclusion, the rate of LRTI and hospital admissions in COPD outpatients with chronic tracheostomy was low, similar to non-COPD patients and independent of P. aeruginosa colonization.

Caregiver Strain Associated With Tracheostomy in Chronic Respiratory Failure

STUDY OBJECTIVES

The aim of this study was to evaluate the psychological and psychosocial impact of tracheostomy on the caregivers of patients who have undergone tracheostomies.

SETTING

Rehabilitation facility.

PARTICIPANTS

Sixty-three lay caregivers of inpatients and outpatients with various underlying diseases who have undergone tracheostomies.

METHODS

At the beginning of the study, the 63 caregivers completed a previously validated questionnaire designed to assess the problems related to caring for patients with chronic diseases. Approximately 1 year later, 40 of the 63 caregivers completed the same questionnaire a second time. The results were analyzed statistically in order to investigate the caregivers' perceptions of the factors associated with their own particular situation.

RESULTS

The answers of the 40 subjects who completed the questionnaire twice revealed the existence of perceived strain persisting over time, which was greater in female caregivers and in those caring for patients who had had a tracheostomy for < 14 months. The younger caregivers (age < 59 years) and those caring for patients receiving nocturnal ventilation expressed a continuing need for information about the disease. Finally, the caregivers said that they, as well as their patients led very restricted personal lives.

CONCLUSIONS

Tracheostomy causes a substantial amount of caregiver strain, which should be taken into account when deciding on any treatment plan.

Quality of Life Evaluation and Survival Study: a 3-yr prospective multinational study on patients with chronic respiratory failure

Therapy of patients with chronic respiratory failure is mainly directed at minimizing symptoms in order to improve, or at least to prevent a deterioration of, patients' well-being. Under such circumstances, the perceived effect of therapies on patients' well-being and daily life represents the most important subjective outcome of treatment. Therefore, there is a need to provide a global estimate of health in patients on long term oxygen therapy or overnight home mechanical ventilation. The Maugeri Foundation Respiratory Failure Questionnaire (MRF28) is the first health status ("quality of life") questionnaire specifically developed for use in CRF and its items were selected to be applicable to patients with both obstructive and restrictive diseases. The Quality of Life Evaluation and Survival Study (QuESS) is a multinational study with the aim of re-evaluating the natural history of chronic respiratory failure in about 300 patients. To the authors knowledge, the Quality of Life Evaluation and Survival Study is the first study to evaluate the natural history of chronic respiratory failure in such a large number of subjects and with a complete set of data. In fact, both pathophysiologic and health status assessments will be made. Moreover, by collecting data on mortality, disease exacerbations and hospitalization, it will also be possible to verify the predictive ability of health status versus pathophysiology in terms of mortality and healthcare utilization.

Influence of clinical history on airways bacterial colonization in subjects with chronic tracheostomy

Patients with chronic tracheostomy are subject to significant bacterial colonization of the airways, a risk factor for respiratory infections. The aim of our study was to verify whether bacterial colonization and humoral immune response in the airways can be influenced by the disease which led to chronic respiratory failure and tracheostomy. Thirty-nine clinically stable outpatients with chronic tracheostomy were considered: 24 were affected by chronic obstructive pulmonary disease (COPD) (mean age 66 years, range 54-78, M/F 19/3; months since tracheostomy 23, range 3-62), 15 by restrictive lung disease (RLD) (12 thoracic wall deformities, three neuromuscular disease; age 57 years, range 41-72; M/F 3/12, months since tracheostomy 22, range 2-68). Recent antibiotic or corticosteroid treatments (< 1 month) were among exclusion criteria. Bacterial counts were assessed in tracheobronchial secretions with the method of serial dilutions. Identification of bacterial strains was performed by routine methods. Albumin, IgG, A, and M were measured in airways secretions with an immunoturbidimetric method. No significant differences were found between the two groups as regards either the quantitative bacterial cultures (RLD 81.4, 2.6-4200 x 10(4); COPD 75.9, 1.0-1530 x 10(4) colony forming units (cfu)/ml, geometric mean, range) or the prevalence of the main bacterial strains, (Pseudomonas species: 38 and 37%, Serratia marcescens: 31 and 23%, Staphylococcus aureus: 14 and 6%, Proteus species: 3 and 8%, for RLD and COPD respectively) as a percentage of total strains isolated (RLD = 26, COPD = 48). Immunoglobulin levels did not show significant differences, apart from being higher in underweight subjects. We conclude that in our series of stable outpatients with chronic tracheostomy, bacteria-host interaction in the airways was not influenced by the clinical history.

Mechanical ventilation in chronic respiratory insufficiency: report on an Italian nationwide survey. The Italian Telethon Committee and the AIPO Study Group on Pulmonary Rehabilitation and Intensive Care

Respiratory home care is an important aspect of rehabilitation programmes designed for patients needing long-term mechanical ventilation. Many differences have emerged between countries in the long-term care of these patients, depending on the different ways of supplying material, managing patients and providing equipment. The results of analysis of the data obtained in a preliminary survey carried out in 1995-1996 among 115 Italian centres operating in the field of home mechanical ventilation are presented. A questionnaire (all closed-circuit items) consisting of two sections (the first epidemiological, and the second methodological and economic) was sent to all centres. Fifty-seven out of 115 (50%) centres responded to the questionnaire, with a prevalence of responses from the north of Italy (37 centres). The responding centres had been working in this field for a mean period of 6 +/- 3 yrs, and a total of 1,842 patients were surveyed. The analysis focuses on the prevalence of treated diseases, methods of mechanical ventilation, regulation of prescription, evaluations carried out during follow-up, supply of equipment, costs and reimbursement, and relations with volunteer associations. A more thorough approach to all the problems emerging from this Italian survey regarding candidates for home mechanical ventilation is warranted. A more detailed comparative analysis of indications, management and costs vis-à-vis other countries should contribute towards achieving maximum uniformity of standards throughout Europe.

Pulmonary failure as a cause of death in COPD

Data on the outcome of patients with chronic obstructive pulmonary disease (COPD) are limited. We know that the prognosis is poor when respiratory insufficiency develops, but we have little information on the actual cause of death. Epidemiological studies are suitable for the assessment of the prevalence of the disease, but give no details on the actual cause of death. Age and forced expiratory volume in one second (FEV1) have been recognized as the best predictors of mortality in studies designed to quantify survival of COPD patients, particularly when the post-brochodilator value is used, as this provides a better estimate of airway and parenchymal damage. Data from Intensive Care Units on acute respiratory failure have several significant limitations. Firstly, it is probable that some patients elect not to undergo intensive treatment for a terminal bout of respiratory failure, particularly if it is not first episode. Secondly, the actual cause of death is often not described in adequate detail. Hypoxaemia and acidaemia are the main risk factors in acute exacerbation of the disease and the presence of pulmonary infiltrates on chest radiographs worsens the prognosis. A single bout of respiratory failure appears to have no effect on the prognosis of COPD patients after recovery, but there is a consistent increase in mortality after the second episode. It seems possible to manage the majority of episodes of acute respiratory failure with mechanical ventilation administered with noninvasive techniques. When endotracheal intubation is necessary, the prognosis is usually poor and the survival after 1 yr is usually lower than 40%. The role of long-term home mechanical ventilation is still unclear. Results from pivotal studies have been encouraging, although survival is far less impressive than in neuromuscular disorders. In patients with end-stage lung disease, lung transplantation can be considered the only possibility of increasing pulmonary functional capacity. However the technique is reserved only for a highly selected group of patients and data on the long-term outcome are awaited.

Long-term nocturnal mechanical ventilation in patients with kyphoscoliosis

THE AIMS OF OUR STUDY WERE

1) to evaluate the long-term efficacy of nocturnal IPPV either via tracheostomy (tIPPV) or a nasal mask (nIPPV) as a means to improve alveolar ventilation in patients with chronic severe hypercapnia caused by kyphoscoliosis; and 2) to assess the effect of MV on hospitalizations and life-style. Twenty six patients with kyphoscoliosis in chronic respiratory failure were enrolled in the study. Patients were divided into two groups. The first group comprised 13 subjects who had been clinically stable for at least 1 month (arterial carbon dioxide tension (Pa,CO2) 81 +/- 1.5 kPa (60.8 +/- 10.9 mmHg), arterial oxygen tension (Pa,O2) 7.3 +/- 0.8 kPa (54.6 +/- 6.1 mmHg)). The second group comprised 13 patients who were either suffering or recovering from an episode of acute respiratory insufficiency (Pa,CO2 9.0 +/- 1.8 kPa (67.8 +/- 13.3 mmHg), Pa,O2 6.8 +/- 1.1 kPa (51.2 +/- 8.2 mmHg), breathing supplemental oxygen in seven cases). Patients in the first group were treated with nocturnal IPPV via a nasal mask, whilst those in the second received nocturnal IPPV via tracheostomy. Similar improvements in arterial blood gases (ABGs) were achieved with both methods. Despite the differences in the degree of severity at baseline, after 1 month, ABG values were: Pa,CO2 6.2 +/- 0.6 kPa (46.6 +/- 4.4 mmHg), Pa,O2 9.0 +/- 1.3 kPa (67.5 +/- 9.6 mmHg) (nIPPV patients); Pa,CO2 6.1 +/- 0.9 kPa (46.1 +/- 6.8 mmHg), Pa,O2 9.8 +/- 1.3 kPa (73.6 +/- 9.8 mmHg) (tIPPV patients). After 1 yr, this improvement was still evident. Days of hospitalization were significantly reduced in both groups during the first year of MV. We conclude that both tIPPV and nIPPV are effective in the long-term treatment of respiratory failure in patients with kyphoscoliosis. It would appear from our data that if nIPPV is initiated early in the evolution of chronic respiratory failure in patients with kyphoscoliosis it will delay the necessity to use an invasive technique; however, long-term follow-up studies and larger case series are needed to demonstrate this.

Intermediate respiratory care unit: rehabilitation

The ventilator assisted individual (VAI) represents a complex set of medical and social issues that call for the involvement of multiple interest groups. The success of treatment for VAI depends on many factors. These include: appropriate selection of patients for care outside the hospital, clinical and physiological stability of patients, patient and family motivation, and their ability to learn. Assisted ventilation in chronic respiratory failure secondary to chest-wall deformities and neuromuscular disease has shown promising results. Less satisfactory have been those reported in patients with chronic obstructive pulmonary disease (COPD). COPD candidates for chronic mechanical ventilation should be carefully selected. Patients should not be discharged on ventilators to nonhospital environments before they are clinically stable. It is also crucial to rule out other medical diseases that could interfere with successful discharge and home-care. Discharge planning requires the support and involvement of the physicians, nurses, and other allied health professionals. Education is of vital importance and, as such, needs to begin early in the patient's hospital stay. A basic checklist of skills that the VAI and the family will need to know should be developed, as well as an individual rehabilitation programme planned according to the patient's primary problem, with realistic short- and long-term goals. The aim is to restore and maintain the best possible quality of life for the individual.

In vitro effect of beta 2-agonists on bacterial killing and superoxide anion (O2-) release from alveolar macrophages of patients with chronic bronchitis

A new class of long-acting beta 2-adrenoceptor agonists has been studied in the last few years. Apparently, they display an important anti-inflammatory activity with an inhibition of different cellular functions. This study was carried out to compare a long-acting beta 2-agonist, formoterol, with a conventional short-acting one, salbutamol, on the release of superoxide anion (O2-) and bacterial killing by alveolar macrophages obtained with bronchoalveolar lavage (BAL) from 20 patients with chronic bronchitis. The O2- production in basal conditions was not affected by beta 2-agonists. On the contrary, after phagocytosis of opsonized zymosan 10(-5) M formoterol significantly affected the phagocytic index (difference between stimulated and basal O2- release): 7.9 +/- 2.0 nM O2-/10(6) AM/10 min vs 16.8 +/- 2.5, p < 0.0007. Bacterial killing was inhibited by the two drugs in a dose-dependent way, but the effect of formoterol was more evident than that of salbutamol. After blocking beta 2-receptors with propranolol, we observed a prevention of the beta 2-agonist effects on both O2- release and bacterial killing. The inhibition of the alveolar macrophage functions considered in this study is evident for both beta 2-agonists, but it is significantly more pronounced for formoterol. Our data can be interpreted as one possible mechanism of the anti-inflammatory effect described for long-acting beta 2-agonists. On the other hand, also a potential suppression of pulmonary antibacterial defenses must not be overlooked, particularly in chronic bronchitis, a disease characterized by recurrent airways infections. Whether current therapeutic dosages are sufficient to achieve anti-inflammatory or microbicidal suppressive effects of clinical relevance has not been demonstrated so far.

Long-term oxygen therapy in patients with diagnoses other than COPD

Long-term O2 prescription in chronic non-COPD hypoxic lung disease is, at present, based largely on physiological rather than on clinical studies. Controlled long-term studies in this field are difficult to perform. The cooperation of many centers is necessary to obtain a large and homogeneous population as the incidence of these diseases is significantly lower than COPD.

Proposal of an easy method to improve routine sputum bacteriology

The study of bacterial flora of the lower respiratory tract is very important for the diagnosis of pulmonary infections and proper therapy but it has to face important methodologic problems. The main problem is contamination of the sputum during its passage through the upper airways. The present study suggests an improved procedure aiming first of all at reducing the specimen contamination by upper airway bacteria by means of a preliminary mouth wash, and secondly at comparing qualitative and quantitative cultures of spit with those of sputum. In our study bronchial lavage aspirate (BLA) cultures were used as a control. Both definite (80 patients) and random (20 patients) sequence sampling procedures were considered to show the importance of a correct sequential specimen collection. Bacteria isolated in the sputum and/or in BLA but absent in the spit were considered the most probable responsible for an eventual pulmonary infection. On the contrary a germ found in the spit and eventually in the sputum but not in BLA was considered responsible for only an eventual inflammation of the upper respiratory tract. Doubtful cases were solved by comparing the different bacterial concentrations in the various samples. A preliminary mouth washing procedure decreased the mean concentration of contaminants in the sputum: 3.6 +/- 7.5 x 10E8 (E = exponent) versus 3.7 +/- 7.2 x 10E7 CFU/ml spit versus sputum (80 patients) p less than 0.001. On the contrary if sputum preceded spit (12 out of the 20 randomly treated subjects), bacterial counts were not significantly different (2.1 +/- 5.7 x 10E8 vs. 1.3 +/- 2.9 x 10E8 CFU/ml, respectively, p = NS). In the group of correctly treated patients (80 subjects) only infrequently oral contaminants were found in BLA (12.5%). The finding of bacteria in BLA but absent in spit and/or sputum was rare (4.8%) suggesting that, at least in chronic obstructive lung disease (COLD) patients, spit and sputum quantitative and qualitative cultures may be sufficient for a good microbiologic examination in almost all the cases.