Architecture of the bacteriophage lambda tail

Bacteriophage lambda has a double-stranded DNA genome and a long, flexible, non-contractile tail encoded by a contiguous block of 11 genes downstream of the head genes. The tail allows host recognition and delivery of viral DNA from the head shell to the cytoplasm of the infected cell. Here, we present a high-resolution structure of the tail complex of bacteriophage lambda determined by cryoelectron microscopy. Most component proteins of the lambda tail were determined at the atomic scale. The structure sheds light on the molecular organization of the extensively studied tail of bacteriophage lambda.

Pre-clinical investigation of liquid sirolimus for local drug delivery

Introduction

Sirolimus is currently being explored as an alternative drug to paclitaxel for the treatment of peripheral artery disease (PAD). To date, sirolimus has only been used as drug coatings for stents and balloons and no studies have yet demonstrated the delivery of sirolimus in liquid form. The purpose of this pilot study was to investigate the feasibility of the delivery of liquid sirolimus into arterial segments in a benchtop peripheral artery bioreactor.

Methods

The feasibility to deliver liquid therapy was first tested on four drug delivery devices using a fluorescently tagged liquid drug and an ex vivo porcine artery benchtop model. The four devices included the Bullfrog micro-infusion device, ClearWay RX catheter, Occlusion perfusion catheter (OPC), and the targeted adjustable pharmaceutical administration system (TAPAS). Penetration of the fluorescently tagged drug was measured via microscopic imaging and quantification of the depth of drug penetration into all device-treated tissue. Based on the penetration outcome, we then selected a single device to deliver liquid sirolimus into the ex vivo porcine artery model undergoing physiological flow and pressure conditions. The liquid sirolimus-treated arteries were collected from the ex vivo bioreactor at 1- and 24-hour post-delivery and arterial drug retention analyzed by liquid chromatography-tandem mass spectrometry.

Results

Fluorescent microscopy demonstrated that drug delivery with the OPC had greater drug penetration into the medial wall as compared to other devices (OPC: 234 ± 161 µm; TAPAS: 127 ± 68 µm; ClearWay: 118 ± 77 µm; Bullfrog: 2.12 ± 3.78 µm; p = 0.098). The results of the ex vivo flow-circuit bench top model showed that the OPC device successfully delivered the liquid sirolimus at 1-hour (5.17 ± 4.48 ng/mg) and 24-hour (0.78 ± 0.55 ng/mg).

Conclusions

These results demonstrate for the first time the ability to deliver liquid sirolimus directly to the medial layer of an artery via a liquid delivery catheter.

Choosing nasal devices: a dilemma in clinical practice

BACKGROUND AND AIM

Upper airway diseases are frequent and recognize different etiopathogenetic mechanisms, including infection, inflammation, and allergy. Therefore, topical treatments are preferable in comparison with systemic medications. Several delivery devices are available on the market, including nasal drops, syringes, sprays, nebulizers, and douches. However, it is clinically relevant to know the better way to use it.

METHODS

The present experience compared five different devices that were tested: i) a nasal dropper, ii) a standard nasal spray device, iii) a mucosal atomization device with a nozzle tip, iv) a nebulizer device, and v) a nasal douche. Saline solution with methylene blue was the marker to evaluate the intranasal distribution.

RESULTS

The findings showed an apparent difference in area distribution among these delivery devices. Conclusion The present experience showed that doctors should choose the most appropriate device for the current disease in clinical practice.

Medical Device Development for Children and Young People-Reviewing the Challenges and Opportunities

Development of specific medical devices (MDs) is required to meet the healthcare needs of children and young people (CYP). In this context, MD development should address changes in growth and psychosocial maturation, physiology, and pathophysiology, and avoid inappropriate repurposing of adult technologies. Underpinning the development of MD for CYP is the need to ensure MD safety and effectiveness through pediatric MD-specific regulations. Contrary to current perceptions of limited market potential, the global pediatric healthcare market is expected to generate around USD 15,984 million by 2025. There are 1.8 billion young people in the world today; 40% of the global population is under 24, creating significant future healthcare market opportunities. This review highlights a number of technology areas that have led to successful pediatric MD, including 3D printing, advanced materials, drug delivery, and diagnostic imaging. To ensure the targeted development of MD for CYP, collaboration across multiple professional disciplines is required, facilitated by a platform to foster collaboration and drive innovation. The European Pediatric Translational Research Infrastructure (EPTRI) will be established as the European platform to support collaboration, including the life sciences industrial sector, to identify unmet needs in child health and support the development, adoption, and commercialization of pediatric MDs.

[Technical features of esophageal stent deployment]

OBJECTIVE

To work out the optimal technique of endoscopic stenting of the esophagus (ESE) using various delivery devices (DD); to analyze immediate and long-term results of stenting depending on the type of DD.

MATERIAL AND METHODS

ESE results were studied in 83 patients. Group 1 included 41 patients with implantation of metal stents delivered on a knitted tubular casing (21 stents with proximal opening and 20 stents with distal opening). Group 2 consisted of 42 patients who underwent ESE using a DD in the form of a contracting outer shell.

RESULTS

In the 1^st group, DD «stumbling» in 6 cases (14.6%) required additional tubular hollow rigid conductor. In the 2^nd group, there was no need for additional conductor (p=0.011). Intraoperative stent repositioning after its initial installation was required in 7 cases (17.1%) of the 1^st group and 16 cases (38.1%) of the 2^nd group (p=0.033). Higher likelihood of stent repositioning was observed in distal stent opening. Technical success rate was 100% in both groups. Clinical success rate was 100% in the 1^st group and 97.6% in the 2^nd group (p>0.05). Incidence of early and long-term postoperative complications was similar (p>0.05).

CONCLUSION

ESE with various DDs is safe and effective in patients with malignant unresectable esophageal tumors and symptoms of dysphagia. However, certain features of stent installation should be considered. In our opinion, DD with proximal disclosure is more convenient due to better visual positioning of stent.

Biogenesis of a Bacteriophage Long Non-Contractile Tail

Siphoviruses are main killers of bacteria. They use a long non-contractile tail to recognize the host cell and to deliver the genome from the viral capsid to the bacterial cytoplasm. Here, we define the molecular organization of the Bacillus subtilis bacteriophage SPP1 ~ 6.8 MDa tail and uncover its biogenesis mechanisms. A complex between gp21 and the tail distal protein (Dit) gp19.1 is assembled first to build the tail cap (gp19.1-gp21Nter) connected by a flexible hinge to the tail fiber (gp21Cter). The tip of the gp21Cter fiber is loosely associated to gp22. The cap provides a platform where tail tube proteins (TTPs) initiate polymerization around the tape measure protein gp18 (TMP), a reaction dependent on the non-structural tail assembly chaperones gp17.5 and gp17.5* (TACs). Gp17.5 is essential for stability of gp18 in the cell. Helical polymerization stops at a precise tube length followed by binding of proteins gp16.1 (TCP) and gp17 (THJP) to build the tail interface for attachment to the capsid portal system. This finding uncovers the function of the extensively conserved gp16.1-homologs in assembly of long tails. All SPP1 tail components, apart from gp22, share homology to conserved proteins whose coding genes' synteny is broadly maintained in siphoviruses. They conceivably represent the minimal essential protein set necessary to build functional long tails. Proteins homologous to SPP1 tail building blocks feature a variety of add-on modules that diversify extensively the tail core structure, expanding its capability to bind host cells and to deliver the viral genome to the bacterial cytoplasm.

Mucosal Vaccination via the Respiratory Tract

Vaccine delivery via mucosal surfaces is an interesting alternative to parenteral vaccine administration, as it avoids the use of a needle and syringe. Mucosal vaccine administration also targets the mucosal immune system, which is the largest lymphoid tissue in the human body. The mucosal immune response involves systemic, antigen-specific humoral and cellular immune response in addition to a local response which is characterised by a predominantly cytotoxic T cell response in combination with secreted IgA. This antibody facilitates pathogen recognition and deletion prior to entrance into the body. Hence, administration via the respiratory mucosa can be favoured for all pathogens which use the respiratory tract as entry to the body, such as influenza and for all diseases directly affecting the respiratory tract such as pneumonia. Additionally, the different mucosal tissues of the human body are interconnected via the so-called “common mucosal immune system”, which allows induction of an antigen-specific immune response in distant mucosal sites. Finally, mucosal administration is also interesting in the area of therapeutic vaccination, in which a predominant cellular immune response is required, as this can efficiently be induced by this route of delivery. The review gives an introduction to respiratory vaccination, formulation approaches and application strategies.

Shared Decision-Making in Growth Hormone Therapy-Implications for Patient Care

Several studies have shown that adherence to growth hormone therapy (GHT) is not optimal. There are several reasons why patients may not fully adhere to their treatment regimen and this may have implications on treatment success, patient outcomes and healthcare spending and resourcing. A change in healthcare practices, from a physician paternalistic to a more patient autonomous approach to healthcare, has encouraged a greater onus on a shared decision-making (SDM) process whereby patients are actively encouraged to participate in their own healthcare decisions. There is growing evidence to suggest that SDM may facilitate patient adherence to GHT. Improved adherence to therapy in this way may consequently positively impact treatment outcomes for patients. Whilst SDM is widely regarded as a healthcare imperative, there is little guidance on how it should be best implemented. Despite this, there are many opportunities for the implementation of SDM during the treatment journey of a patient with a GH-related disorder. Barriers to the successful practice of SDM within the clinic may include poor patient education surrounding their condition and treatment options, limited healthcare professional time, lack of support from clinics to use SDM, and healthcare resourcing restrictions. Here we discuss the opportunities for the implementation of SDM and the barriers that challenge its effective use within the clinic. We also review some of the potential solutions to overcome these challenges that may prove key to effective patient participation in treatment decisions. Encouraging a sense of empowerment for patients will ultimately enhance treatment adherence and improve clinical outcomes in GHT.

The pharmacokinetics, safety, and tolerability of single, high-strength doses of fluticasone propionate and fluticasone propionate/salmeterol delivered via a novel multidose dry powder inhaler in adolescents and adults with persistent asthma

OBJECTIVE

Characterize fluticasone propionate (Fp) and combination fluticasone propionate and salmeterol (FS) pharmacokinetic and safety profiles, delivered via a novel, inhalation-driven, multidose dry powder inhaler (MDPI).

METHODS

This multicenter, open-label, four-period crossover, single-dose study randomized patients aged ≥12 years with persistent asthma to Fp MDPI 200 mcg, FS MDPI 200/12.5 mcg, Fp dry powder inhaler (DPI) 500 mcg (250 mcg × 2 inhalations), or FS DPI 500/50 mcg. Blood samples for determination of Fp and salmeterol pharmacokinetic parameters including C_max, AUC_0-t, AUC_0-inf, t_max, and t_½ were collected predose through 36 h postdose (14 time points). Safety assessments comprised adverse events, vital signs, and physical examinations. The institutional review board approved the study protocol.

RESULTS

The pharmacokinetic analysis set and safety population each included 40 patients. Fp systemic exposure (C_max, AUC_0-t, and AUC_0-inf) was highest for Fp DPI 500 mcg and similar for Fp MDPI 200 mcg, FS MDPI 200/12.5 mcg, and FS DPI 500/50 mcg. Fp geometric mean t_½ values were similar across treatments. Salmeterol C_max was 20% lower and AUC_0-t and AUC_0-inf were approximately 50% lower with FS MDPI versus FS DPI. Median t_max and geometric mean t_½ were similar between FS MDPI and FS DPI. Adverse events were similar across treatments with no relevant changes in vital signs, physical examinations, or hematology test results.

CONCLUSIONS

Fp MDPI and FS MDPI produced similar or lower systemic exposure to Fp and salmeterol, despite lower doses, versus conventional DPI devices, suggesting improved efficiency due to formulation and device differences.

Should Aerosolized Antibiotics Be Used to Treat Ventilator-Associated Pneumonia?

In patients with ventilator-associated pneumonia, systemic use of antibiotics is the cornerstone of medical management. Supplemental use of aerosolized antibiotics with intravenous antibiotics in both experimental and clinical studies has been shown to have the following pharmacologic benefits: (1) aerosolized antibiotics reach the infected lung parenchyma without crossing the pulmonary alveolar capillary barrier; (2) aerosolized antibiotics increase anti-bacterial efficacy through increased local antibiotic concentration; and (3) aerosolized antibiotics decrease systemic toxicity. These benefits may be particularly beneficial to treat pneumonia caused by multidrug-resistant pathogens. Clinical data on the benefits of aerosolized antibiotics are more limited. Studies to date have not clearly shown improvements in time to extubation, mortality, or other patient-centered outcomes. At present, amikacin, colistin, and ceftazidime are the most frequently used and studied aerosolized antibiotics. This review summarizes the characteristics of aerosolized antibiotics, reviews the advantages and disadvantages of using aerosolized antibiotics, and calls for future investigations based on animal study data.

Comparison of the local pulmonary distribution of nanoparticles administered intratracheally to rats via gavage needle or microsprayer delivery devices

Intratracheal administration methods are used to conduct toxicological assessments of inhaled nanoparticles (NPs), and gavage needles or microsprayers are common intratracheal delivery devices. The NP suspension is delivered in a liquid state via gavage needle and as a liquid aerosol via microsprayer. The differences in local pulmonary NP distribution (called the microdistribution) arising from the different states of the NP suspension cause differential pulmonary responses; however, this has yet to be investigated. Herein, using microbeam X-ray fluorescence microscopy, we quantitatively evaluated the TiO₂ pulmonary microdistribution (per mesh: 100 μm × 100 μm) in lung sections from rats administered an intratracheal dose of TiO₂ NPs (6 mg kg^-1 ) via gavage needle or microsprayer. The results revealed that: (i) using a microsprayer appears to reduce the variations in TiO₂ content (ng mesh^-1 ) among rats (e.g., coefficients of variation, n = 3, microsprayer vs gavage needle: 13% vs 30%, for the entire lungs); (ii) TiO₂ appears to be deposited less in the right middle lobes than in the rest of the lung lobes, irrespective of the chosen intratracheal delivery device; and (iii) similar TiO₂ contents (ng mesh^-1 ) and frequencies are deposited in the lung lobes of rats administered TiO₂ NPs via gavage needle or microsprayer. This suggests that the physical state of the administered NP suspension does not markedly alter TiO₂ pulmonary microdistribution. The results of this investigation are important for the standardization of intratracheal administration methods. Copyright © 2016 John Wiley & Sons, Ltd.

Intratracheal Administration of Antimicrobial Agents in Mechanically Ventilated Adults: An International Survey on Delivery Practices and Safety

BACKGROUND

Intratracheal antibiotic administration is increasingly used for treating respiratory infections. Limited information is available on delivery devices, techniques, and safety.

METHODS

An online survey on intratracheal administration of anti-infective agents in mechanically ventilated adults was answered by health-care workers from 192 ICUs to assess the most commonly used devices, current delivery practices, and safety issues. We investigated whether ICU usage experience (≥3 y) impacted its performance.

RESULTS

Intratracheal antibiotic administration was a current practice in 87 ICUs (45.3%), with 40 (46%) having experience with the technique (≥3 y). Sixty-six (78.6%) of 84 health-care workers reported avoiding intratracheal antibiotic administration due to an absence of evidence-based guidelines (78.6%). Jet nebulizers were the most commonly used devices for delivery, in 24 less experienced ICUs (27.6%) and in 18 (20.7%) experienced ICUs. Direct tracheal instillation (6; 6.9%) was still considered for drug prescription in 12 ICUs (6.9%). More experience resulted in neither greater adherence to measures improving the drug's delivery efficiency (93 measures in the experienced group; 27.9%) nor a greater adoption of measures to increase safety. Indeed, the expiratory filter was changed after each nebulization in only 2 experienced ICUs (6.9%), whereas 15 (51.7%) changed it daily instead.

CONCLUSIONS

Intratracheal antibiotic administration is a common therapeutic modality in ICUs, but inadequate practices were widely encountered, independent of the level of experience with the technique. This suggests a need to develop standardization to reduce variability and improve safety and efficacy.

Year in Review 2014: Aerosol Delivery Devices

After centuries of discoveries and technological growth, aerosol therapy remains a cornerstone of care in the management of both acute and chronic respiratory conditions. Aerosol therapy embraces the concept that medicine is both an art and a science, where an explicit understanding of the science of aerosol therapy, the nuances of the different delivery devices, and the ability to provide accurate and reliable education to patients become increasingly important. The purpose of this article is to review recent literature regarding aerosol delivery devices in a style that readers of Respiratory Care may use as a key topic resource.

User preference for a portable syringe pump for iloprost infusion

Purpose

Administration of intravenous iloprost – a first-line European League Against Rheumatism (EULAR)-recommended choice for the treatment of scleroderma (SSc)-related digital vasculopathy – requires repeated treatment cycles of 6 hours per day in a hospital setting. During the infusion, patient mobility is considerably restricted due to the size and fixity of traditional syringe pumps. The aim of this study was to evaluate the satisfaction level of patients and nurses, after the introduction of a new portable syringe pump (Infonde^®, Italfarmaco S.p.A., Milan, Italy) at the Department of Rheumatology, Magenta Hospital, Milan, Italy.

Patients and methods

Thirty-four consecutive SSc patients receiving stable therapy with iloprost, previously administered with a fixed pump, were treated using the portable Infonde^® pump. Patients (n=34) and nurses (n=4) were asked to answer a nine- and six-item questionnaire, respectively, to assess the satisfaction of the administration comparing the new device versus the previous one. The health care staff of the ward developed the questionnaire, and the response scores ranged from 0 (fixed device better) to 10 (portable device better); thus a score >5 indicates a preference for Infonde^®.

Results

Patients’ answers indicated a preference towards the new portable syringe pump, versus the previous fixed pump. Questionnaires administered to patients generated a total of 306 responses, with over 95% of the responses in the range 8–10, of which 89% had a score equal to 10. The responses of nurses showed a score equal to 10 in 100% cases. No significant adverse events were recorded, indicating no change in the tolerability profile of the drug.

Conclusion

Iloprost administration with Infonde^® pump was preferred by both patients and health care professionals, and was well tolerated. The possibility to perform daily activities and the freedom of movement suggest a positive impact of Infonde^® on the treatment, with a potential favorable effect on the quality of life of patients during the many hours spent receiving the infusion.

Albuterol delivery via metered dose inhaler in a spontaneously breathing pediatric tracheostomy model

RATIONALE

Little data are available regarding efficiency of drug delivery devices and techniques despite their widespread use in spontaneously breathing tracheostomized patients. We compared patient dose achieved with different devices, inhalation techniques, tracheostomy tube sizes and breathing patterns using a spontaneously breathing tracheostomized pediatric model.

METHODS

A tracheostomy model was connected in series to a breathing simulator with a filter interposed (patient dose). Breathing patterns of a 16-month-old and a 6- and 12-year-old child with tracheostomy with internal diameters (mm) of 3.5, 4.5, and 5.5 were used. Albuterol HFAp MDI was used. Aerotrach Plus, MediBag, Aerochamber MV, Aerochamber Mini, and inline adapter with 6-inch tubing were tested. The latter 3 devices were also tested with assisted technique. Albuterol was analyzed via spectrophotometry.

RESULTS

Aerotrach Plus outperformed almost all devices tested. Aerochamber MV with unassisted technique was the second best and the adapter was the worst. Comparison of efficiency between best and worst performer ranged from 3- to 17.2-fold. The 16-month-old breathing pattern and the 3.5 mm tracheostomy tube had the lowest patient dose. The use of assisted technique decreased patient dose by 18-67% for the 4.5 and 5.5 mm but not for 3.5 mm tracheostomy tubes. A median of 7.4% of the nominal dose was deposited in the tracheostomy tubes.

CONCLUSIONS

Aerotrach Plus and the adapter were the most and least efficient devices respectively. Tracheostomy size and breathing pattern affected drug delivery. The use of assisted technique reduced aerosol delivery.

Analysis and perspective: A randomized, open-label, comparative crossover handling trial between two durable pens in patients with type 1 or 2 diabetes mellitus

Insulin pen therapy is superior to vial and syringe with regard to more accurate insulin delivery, patient preference, adherence, and favorable health economics. In this issue of Journal of Diabetes Science and Technology, Sommavilla and Pietranera compare two generations of NovoPen, showing significant improvements in selecting and injecting the insulin dose as well as superior overall satisfaction with the newer versus older generation insulin pen among both experienced pen users and insulin-naïve patients. There are other potentially useful features that might be implemented and better-studied in future pen devices. These include insulin dose tracking, insulin error mitigation, and insulin dosing advice. Caring more effectively for the multitude of people impacted by the diabetes epidemic requires a new approach that will require "smarter," more "connected" devices.