Decreasing Sedentary Behaviors in Youth to Prevent and Manage Childhood Obesity: Is It Realistic?

PURPOSE OF REVIEW

Decreasing sedentary behaviors has been proposed as one approach to reduce the rate of obesity in youth. This review summarizes the contemporary literature examining the efficacy of these interventions in the school and community along with an additional focus on the role of socioeconomic status in these interventions.

RECENT FINDINGS

Studies that focus on decreasing sedentary behavior have utilized a wide variety of strategies in a number of settings. The effects of these interventions are often hindered by non-standard outcome measures, study infidelity, and subjective measures of sedentary time. However, interventions that incorporate engaged stakeholders and include younger subjects appear to be the most likely to succeed. Promising interventions to decrease sedentary behaviors have been shown in recent clinical trials; however, replicating and sustaining these results is challenging. From the available literature, school-based interventions have the potential of reaching the largest group of children. In contrast, interventions in younger children, particularly those with invested parents, seem to be the most effective.

Socioeconomic Status and Kawasaki Disease Outcomes in a Single-Payer Health Care System

Background

For patients with Kawasaki disease (KD), lower socioeconomic status (SES) may adversely affect the timeliness of presentation and initiation of intravenous immune globulin, and coronary artery outcomes. Multipayer systems have been shown to affect health care equity and access to health care negatively. We sought to determine the association of SES with KD outcomes in a single-payer health care system.

Methods

Patients with KD presenting from 2007 to 2017 at a single institution were included. SES data were obtained by matching patient postal code district with data from the 2016 Census Canada.

Results

SES data were linked for 1018 patients. The proportion of households living below the after-tax low-income cutoff in the patient's postal code district was 13% for not treated, 13% for delayed intravenous immune globulin treatment, and 12% for prompt treatment (P = 0.58). Likewise, the average median annual household income was unrelated to delayed or no treatment. The percentage >15 years of age with advanced education differed between groups at 33%, 29%, and 31% for delayed treatment, prompt treatment, and missed groups, respectively (P = 0.004). SES variables were not significantly different for those with vs without coronary artery aneurysms (max Z-score: >2.5), including the proportion of households living below low-income cutoff (12% vs 13%; P = 0.37), average median annual household income (CAD$81,220 vs $82,055; P = 0.78), and proportion with a university degree (33% vs 31%; P = 0.49), even after adjusting for sex, age, year, and KD type.

Conclusions

Timeliness of treatment for KD and coronary artery outcomes were not associated with SES variables within a single-payer health care system.

Quantitative Assessment and Spatial Analysis of Metals and Metalloids in Soil Using the Geo-Accumulation Index in the Capital Town of Romblon Province, Philippines

The municipality of Romblon in the Philippines is an island known for its marble industry. The subsurface of the Philippines is known for its limestone. The production of marble into slab, tiles, and novelty items requires heavy equipment to cut rocks and boulders. The finishing of marble requires polishing to smoothen the surface. During the manufacturing process, massive amounts of particulates and slurry are produced, and with a lack of technology and human expertise, the environment can be adversely affected. Hence, this study assessed and monitored the environmental conditions in the municipality of Romblon, particularly the soils and sediments, which were affected due to uncontrolled discharges and particulates deposition. A total of fifty-six soil and twenty-three sediment samples were collected and used to estimate the metal and metalloid (MM) concentrations in the whole area using a neural network-particle swarm optimization inverse distance weighting model (NN-PSO). There were nine MMs; e.g., As, Cr, Ni, Pb, Cu, Ba, Mn, Zn and Fe, with significant concentrations detected in the area in both soils and sediments. The geo-accumulation index was computed to assess the level of contamination in the area, and only the soil exhibited contamination with zinc, while others were still on a safe level. Nemerow's pollution index (NPI) was calculated for the samples collected, and soil was evaluated and seen to have a light pollution level, while sediment was considered as "clean". Furthermore, the single ecological risk (Er) index for both soil and sediment samples was considered to be a low pollution risk because all values of Er were less than 40.

Late Complication of Congenital Diaphragmatic Hernia Repair: Recurrent Small Bowel Obstruction

ABSTRACT

Congenital diaphragmatic hernia (CDH) is associated with high early mortality. However, advances in newborn care have led to improved survival into adolescence and early adulthood. We report a 17-year-old adolescent boy with recurrent small bowel obstruction after CDH repair at 2 days of age. Emergency physicians should be aware of late complications after neonatal CDH repair.

Career decision making in undergraduate medical education

BACKGROUND

It is unclear how medical students prioritize different factors when selecting a specialty. With rising under and unemployment rates a novel approach to career counselling is becoming increasingly important. A better understanding of specialty selection could lead to improved career satisfaction amongst graduates while also meeting the health care needs of Canadians.

METHODS

Medical students from the University of Toronto participated in a two-phase study looking at factors impacting specialty selection. Phase I consisted of focus groups, conducted independently for each year, and Phase II was a 21-question electronic survey sent to all students.

RESULTS

Twenty-one students participated in the focus group phase and 95 in the survey phase. Primary themes related to career selection identified in Phase I in order of frequency included personal life factors (36), professional life factors (36), passion/interest (20), changing interests (19) and hidden curriculum (15). The survey phase had similar results with passion (83), lifestyle (79), flexibility (75), employment opportunities (60) and family (50) being ranked as the factors most important in specialty selection.

CONCLUSION

Personal factors, professional factors and passion/interest may be key themes for medical students when deciding which specialty to pursue. Targeting career counselling around these areas may be important.

Keeping caries at bay in breastfeeding babies

As an infant grows, human milk may become the substrate for cariogenic bacteria. Here's what to watch for and how to counsel parents.

The breastfeeding paradox: Relevance for household food insecurity

Mitigating the harmful effects of adverse social conditions is critical to promoting optimal health and development throughout the life course. Many Canadians worry over food access or struggle with household food insecurity. Public policy positions breastfeeding as a step toward eradicating poverty. Breastfeeding fulfills food security criteria by providing the infant access to sufficient, safe and nutritious food that meets dietary needs and food preferences. Unfortunately, a breastfeeding paradox exists where infants of low-income families who would most gain from the health benefits, are least likely to breastfeed. Solving household food insecurity and breastfeeding rates may be best realized at the public policy level. Notably, the health care provider's competencies as medical expert, professional, communicator and advocate are paramount. Our commentary aims to highlight the critical link between breastfeeding and household food insecurity that may provide opportunities to affect clinical practice, public policy and child health outcomes.

The paediatrician and middle childhood parenting

The 'forgotten years' of middle childhood, from age 6 to 12, represent a critical period in child development. Emotional, social and physical development during this time have a lifelong impact on health and adult contributions to society. Mental health conditions have displaced physical illness as the leading childhood disability. Positive parenting can improve child behaviour, prevent early-onset conduct problems and provide a buffer from adverse childhood events resulting in decreased toxic stress and improved health. Medical homes can play a key role in supporting parents with positive parenting skills that are practical, evidence-based and useful in everyday life. Paediatricians need to explore the domains that promote healthy development, including caring environments, fundamental needs and nurturing relationships. Our objective is to promote high-quality positive parenting through middle childhood by identifying opportunities for paediatricians to frame parenting discussions in the context of development, behaviour and safety and to provide access to valuable parenting resources.

Bisphosphocins: novel antimicrobials for enhanced killing of drug-resistant and biofilm-forming bacteria

The global prevalence of antibiotic resistance and the threat posed by drug-resistant superbugs are a leading challenge confronting modern medicine in the 21st century. However, the progress on the development of novel antibiotics to combat this problem is severely lagging. A more concerted effort to develop novel therapeutic agents with robust activity and unique mechanisms of action will be needed to overcome the problem of drug resistance. Furthermore, biofilm forming bacteria are known to be increasingly resistant to the actions of antibiotics and are a leading cause of mortality or morbidity in nosocomial infections. Bisphosphocins (also scientifically known as nubiotics) are novel small protonated deoxynucleotide molecules, and exert their antibacterial activity by depolarization of the bacterial cell membrane, causing bacterial cell death. Bisphosphocins may represent an effective weapon against antibiotic-resistant and biofilm-forming pathogenic bacteria. Preclinical efficacy studies in animals have shown that the compounds are safe and, efficacious against various bacterial infections, including drug-resistant pathogens. In vitro biochemical analysis confirmed that the bactericidal activity of bisphosphocins is mediated by depolarization of the bacterial cell membrane, and these compounds are better able to penetrate through bacterial biofilm and kill the biofilm encased bacteria. This article will cover the structure, mode of action, safety, efficacy and the current state of development of bisphosphocins. Together, the information presented here will present a strong case for bisphosphocins to be considered for use as new weapons to complement the existing arsenal of antimicrobial drugs and as a first line defence against drug-resistant and biofilm-forming bacteria.

Experimental antiviral drugs against pandemic influenza

ABSTRACT 

The aim of this review is to selectively identify some representative experimental antiviral drugs which are promising in preclinical and clinical studies, but yet to be fully licensed, and discuss how they have a potential role in complementing our existing arsenal of antiviral drugs to combat pandemic influenza. This review will focus on discussing their mechanisms of actions, current state of development, safety, efficacy from preclinical and/or clinical studies. These experimental drugs can be classified into virus or host specific, depending on the individual drug's targeting action. This article will highlight novel anti-inflammatory drugs which can be used to mitigate cytokine storm caused by pandemic influenza viruses as a treatment option or strategy.

The potential of liposome-encapsulated ciprofloxacin as a tularemia therapy

Liposome-encapsulation has been suggested as method to improve the efficacy of ciprofloxacin against the intracellular pathogen, Francisella tularensis. Early work with a prototype formulation, evaluated for use against the F. tularensis live vaccine strain, showed that a single dose of liposomal ciprofloxacin given by the intranasal or inhalational route could provide protection in a mouse model of pneumonic tularemia. Liposomal ciprofloxacin offered better protection than ciprofloxacin given by the same routes. Liposomal ciprofloxacin has been further developed by Aradigm Corporation for Pseudomonas aeruginosa infections in patients with cystic fibrosis and non-cystic fibrosis bronchiectasis. This advanced development formulation is safe, effective and well tolerated in human clinical trials. Further evaluation of the advanced liposomal ciprofloxacin formulation against the highly virulent F. tularensis Schu S4 strain has shown that aerosolized CFI (Ciprofloxacin encapsulated in liposomes for inhalation) provides significantly better protection than oral ciprofloxacin. Thus, liposomal ciprofloxacin is a promising treatment for tularemia and further research with the aim of enabling licensure under the animal rule is warranted.

Vaccines and therapeutics for the encephalitic alphaviruses

This article is a review of vaccines and therapeutics in development for the encephalitic alphaviruses, which includes eastern equine encephalitis virus, western equine encephalitis virus and Venezuelan equine encephalitis virus. The encephalitic alphaviruses are endemic within regions in North and South America. Hosts are normally exposed after being bitten by infectious mosquitoes, and infection can develop into encephalitis in equines and humans with severe rates of morbidity and mortality. These viruses are also potential biological threat agents, being highly infectious via an aerosol route of exposure. In humans, equine encephalitis virus and western equine encephalitis virus are neurotropic viruses targeting the CNS and causing encephalitis. Mortality rates are 50 and 10%, respectively, for these viruses. On the other hand, Venezuelan equine encephalitis virus produces a systemic influenza-like illness with pathogenesis in the lungs and lymphoid tissue in adults and older children. The incidence of encephalitis is less than 5% in younger children with a case–mortality rate of 1%. The host response to virus infectivity is briefly discussed, along with a number of promising therapeutic and prophylactic approaches. These approaches can be broadly classified as: virus-specific, including vaccines, antibody therapy and gene-silencing oligonucleotides; or broad-spectrum, including interferon and activation of the host‘s innate immunity.

Recent patents in antiviral siRNAs

The advent of gene silencing siRNA technology has created opportunities to develop therapeutics based on targeting the genomics of the disease state. Amongst the first applications of siRNA technology, antiviral applications have been quickly and extensively exploited allowing emergence of a range of antiviral therapeutic strategies. Patent activity has encompassed a range of the components required to utilize this technology ranging from the identification of susceptible genomic targets through to the development of vector systems to express the siRNA endogenously or the synthesis of stable RNA oligonucleotides for in vivo therapeutics. Indeed the primary focus of research effort in this area has been to overcome the challenge common to all of gene therapeutics - delivery of the oligonucleotide - to the diseased tissues and organs, sites of infection and/or sites of drug action. Here we survey the development of siRNA therapeutics both in terms of the range of virus species targeted and the strategic approaches employed. Our study illustrates features commonly observed in the field of nucleic acid drug development. While in vitro studies provide a broad range of molecules and molecular targets for potential therapeutics, the field is however severely limited in terms of safe, effective means to deliver the potential siRNA therapeutics in vivo, to the intracellular site of action.

Broad-spectrum and virus-specific nucleic acid-based antivirals against influenza

Rapid increase in drug-resistant influenza virus isolates, and pandemic threat posed by highly pathogenic avian influenza A and swine flu viruses provide clear and compelling reasons for fast tracking development of novel antiviral drugs. Nucleic acid-based drugs represent a promising class of novel antiviral agents that can be designed to target various seasonal, pandemic and avian influenza viruses. Nucleic acids can be designed to elicit broad-spectrum antiviral responses in the host, by suppressing viral gene expression, or by inducing cleavage or degradation of viral RNA. Immunomodulating nucleic acids, such as double stranded RNA and CpG oligonucleotides, can be potent anti-influenza agents that work by eliciting protective innate and adaptive immunity in the host. By activating the toll-like receptor signaling pathways, these drugs can activate the host's antiviral and inflammatory defenses to combat influenza viruses. Antisense oligonucleotides, small interfering RNAs (siRNA), and nanoRNAs represent sequence specific gene-silencing approaches that could be deployed to suppress or inhibit viral protein gene expression. Lastly, catalytic nucleic acids such as DNAzymes and/or ribozymes can suppress viral replication by repeatedly cleaving viral mRNAs and template RNAs. In summary, nucleic acid-based antiviral agents are versatile, diverse and could complement existing antiviral drugs in combating influenza.

Antiviral role of toll-like receptor-3 agonists against seasonal and avian influenza viruses

The divergence and antigenic shifts in influenza viruses represent significant challenges for the development of effective vaccines and antiviral drugs against influenza viruses. In view of current challenges and/or deficiencies in the influenza pandemic influenza preparedness, novel antiviral strategies which are robust and can respond to constant viral mutations, are particularly needed to combat future pandemic threats. Toll-like receptor-3 (TLR-3) is an integral part of the host's innate immune system and serves as an important signaling pathway for the recognition of dsRNA for the triggering of antiviral and inflammatory responses to combat viral infections. This review examines dsRNA including Poly ICLC and liposome-encapsulated Poly ICLC (LE Poly ICLC) as TLR-3 agonists for their antiviral activity against seasonal and highly pathogenic avian influenza (HPAI) viruses. Furthermore, their roles in attenuating the antiviral and inflammatory cytokines in the host will also be explored. Preclinical studies in experimental animals suggest Poly ICLC and liposome-encapsulated Poly ICLC are safe and offer broad-spectrum protection against both seasonal and HPAI viruses, as well as other respiratory viruses including respiratory syncytial virus and SARS. Preliminary results from recent studies suggest these drugs up-regulate the production of interferons (-alpha, -beta, and -gamma), and tumor necrosis factor (TNF-alpha) but downregulate some proinflammatory cytokines including IL-2 and IL-4. Taken together, these results suggest these TLR-3 agonists have a promising role to play as safe, effective and broad-spectrum anti-influenza drugs that could complement other antiviral drugs to combat seasonal, zoonotic and pandemic influenza viruses. The clinical safety of these drugs and their efficacy in pre-clinical studies may provide sufficient justification for regulatory agencies to consider their fast track development for use in future outbreaks of pandemic influenza or of other emerging respiratory pathogens.

Broad-spectrum drugs against viral agents

Development of antivirals has focused primarily on vaccines and on treatments for specific viral agents. Although effective, these approaches may be limited in situations where the etiologic agent is unknown or when the target virus has undergone mutation, recombination or reassortment. Augmentation of the innate immune response may be an effective alternative for disease amelioration. Nonspecific, broad-spectrum immune responses can be induced by double-stranded (ds)RNAs such as poly (ICLC), or oligonucleotides (ODNs) containing unmethylated deocycytidyl-deoxyguanosinyl (CpG) motifs. These may offer protection against various bacterial and viral pathogens regardless of their genetic makeup, zoonotic origin or drug resistance.

Recent Patents on development of nucleic acid-based antiviral drugs against seasonal and pandemic influenza virus infections

Influenza viruses are etiological agents of deadly flu that continue to pose global health threats, and have caused global pandemics that killed millions of people worldwide. The global crisis involving the avian H5N1 influenza provides compelling reasons to accelerate fast track development of novel antiviral drugs against the potential pandemic virus. The availability of neuraminidase inhibitors such as oseltamivir (tamiflu) improves our ability to defend against influenza viruses, but the incidences of tamiflu-resistance are rising rapidly. Nucleic acid-based antiviral drugs are promising classes of experimental antiviral drugs that have been shown in pre-clinical studies to be effective against seasonal and avian influenza viruses. The potency and versatility of these drugs make them potential candidates to be used in seasonal and pandemic influenza scenarios. The review will assess the recent patents, research and development of antisense oligonucleotides, small interfering RNA, immunomodulating RNA for the prevention and treatment of influenza infection.

Protective role of DNA vaccination and passive immunization against the 1918 pandemic influenza virus

Evaluation of: Kong W-P, Hood C, Yang Z-Y et al.: Protective immunity to lethal challenge of the 1918 pandemic influenza virus by vaccination. Proc. Natl Acad. Sci. USA 103(43), 15987–15991 (2006). Lessons learnt from the 1918 Spanish influenza pandemic indicate that the world is vulnerable to pandemic viruses and that effective medical countermeasures are urgently needed to protect against future pandemics. The work, as published by Kong and colleagues, involved the use of genetically reconstructed 1918 pandemic virus and is of significant importance for a number of reasons. First, it highlights how advanced technology such as DNA vaccination could provide a modern solution for protection against a historic killer virus, such as the 1918 Spanish flu virus, and second, this paper describes the elucidation of the protective immunity that contributes to neutralization of virus infectivity, and therefore provides insights on the role of humoral and cellular responses in contributing to protective immunity against this virus. Third, it highlights the effectiveness of passive immunization using neutralizing antibody to protect against lethal virus challenge. The scientific information provided in this study is of significant importance in increasing our understanding of the infectivity and immunity of pandemic virus, and may better enhance our ability to prevent and treat future influenza infection caused by pandemic viruses.

Nucleic acid-based antiviral drugs against seasonal and avian influenza viruses

Influenza viruses are etiological agents of deadly flu that continue to pose global health threats, and have caused global pandemics that killed millions of people worldwide. The availability of neuraminidase inhibitors and attenuated vaccines improves our ability to defend against influenza, but their benefits can be significantly limited by drug-resistance and virus mutations. Nucleic acid-based drugs may represent a promising class of antiviral agents that could play a role in the prevention and treatment of influenza. Efficacy studies in animals have shown that ds RNA, such as poly ICLC can provide effective and broad-spectrum prophylaxis against lethal challenges against various strains of influenza A virus. Furthermore, similar level of antiviral protection in mice can be provided by using short fragments of oligonucleotides that induce antiviral immunity. Finally, influenza virus expression can also be specifically inhibited or suppressed using antisense oligonucleotides that bind to viral mRNA encoding key viral proteins. The versatility and potency of nucleic acid-based drugs make them potential drug candidates for used in seasonal or pandemic influenza situations.

Infectivity variation and genetic diversity among strains of Western equine encephalitis virus

Variation in infectivity and genetic diversity in the structural proteins were compared among eight strains of Western equine encephalitis virus (WEEV) to investigate WEEV virulence at the molecular level. A lethal intranasal infectivity model of WEEV was developed in adult BALB/c mice. All eight strains examined were 100 % lethal to adult mice in this model, but they varied considerably in the time to death. Based on the time to death, the eight strains could be classified into two pathotypes: a high-virulence pathotype, consisting of strains California, Fleming and McMillan, and a low-virulence pathotype, comprising strains CBA87, Mn548, B11, Mn520 and 71V-1658. To analyse genetic diversity in the structural protein genes, 26S RNAs from these eight strains were cloned and sequenced and found to have > 96 % nucleotide and amino acid identity. A cluster diagram divided the eight WEEV strains into two genotypes that matched the pathotype grouping exactly, suggesting that variation in infectivity can be attributed to genetic diversity in the structural proteins among these eight strains. Furthermore, potential amino acid differences in some positions between the two groups were identified, suggesting that these amino acid variations contributed to the observed differences in virulence.

Recent Developments in Delivery of Nucleic Acid-Based Antiviral Agents

Rapid advances in viral genomics, gene function and regulation, as well as in rational drug design, have led to the development of gene-based drugs that can induce protective antiviral immunity, interfere with viral replication, suppress viral gene expression or cleave viral mRNAs. Several such drug candidates have been developed in recent years against various viruses including HIV. Although gene-based agents show promise as anti-viral agents their therapeutic efficacy may be restricted by limited delivery to intracellular sites of viral replication and in vivo nuclease degradation. Enhancement of the efficacy of gene-based drugs by encapsulation within liposomes or insertion within viral vectors has been evaluated. This review will highlight recent developments in delivery systems used to target nucleic acid-based drugs into sites of viral replication, therefore avoiding potential drug toxicity in non-viral infected organs. Liposome-encapsulation and insertion of nucleic acid-based drugs within viral vectors can significantly enhance antiviral efficacies. Viral vector-mediated therapy usually results in greater expression of the gene-based drug than with liposome delivery, however significant safety concerns have been raised in regards to viral vector therapies. Research is ongoing to increase drug delivery to the desired target cells while eliminating adverse side effects.

Spray-freeze-dried liposomal ciprofloxacin powder for inhaled aerosol drug delivery

Spray-freeze drying was utilized to manufacture a liposomal powder formulation containing ciprofloxacin as a model active component. The powder forms liposomally encapsulated ciprofloxacin when wetted. Aerosol properties of this formulation were assessed using a new passive inhaler, in which the powder was entrained at a flow rate of 60l/min. A mass median aerodynamic diameter (MMAD) of 2.8 microm was achieved for this formulation. Using the experimental dispersion testing data, ciprofloxacin concentration in the airway surface liquid (ASL) was calculated using a Lagrangian deposition model. The reconstitution of the powder in various aqueous media gave drug encapsulation efficiencies as follows: 50% in water, 93.5% in isotonic saline, 80% in bovine mucin, 75% in porcine mucus and 73% in five-fold-diluted ex vivo human cystic fibrosis patient sputum.

Prophylaxis of acute respiratory virus infections using nucleic acid-based drugs

Acute respiratory virus infections such as SARS and pandemic influenza are highly contagious diseases that cause global crisis, and inflict severe human mortality and morbidity. Vaccines against these viruses are either unavailable or do not provide adequate protection. In the absence of effective vaccines, nucleic acid-based immunomodulators have the potential to offer effective, broad-spectrum protection against these deadly pathogens. Poly ICLC and CpG oligonucleotides are promising gene-based drugs which have been shown in animal studies to protect against acute respiratory virus infections. Poly ICLC is a synthetic double-stranded RNA (dsRNA), and an effective interferon-inducer and natural killer cell activator. When encapsulated in liposomes, poly ICLC offers complete protection (100% survival rate in pretreated group versus 0% survival in control group) against a lethal respiratory challenge of influenza A virus in mice. This antiviral effect has been shown to persist for up to 3 weeks post-drug treatment. Poly ICLC pretreatment also protects mice against a respiratory challenge of western equine encephalitis (WEE) virus, at a level comparable to inactivated WEE vaccine. CpG oligos in liposomes also provided high level of protection against the lethal influenza challenge. Together, these studies suggest nucleic acid-based immunomodulators are promising antiviral agents which can offer effective and non-specific protection against acute respiratory virus infections.

Efficacy of DNA vaccination against western equine encephalitis virus infection

The efficacy of a DNA vaccine against western equine encephalitis (WEE) infection in mice was evaluated. The 26S structural region was expressed, in vitro from an internal T7 promoter using a rabbit reticulysate transcription/translation system; and from a CMV promoter after transfection into Vero cell monolayers. The proteins synthesized were reactive with anti-WEE virus (WEEV) antibodies, both in western blot analysis and histochemical staining, respectively. When the DNA vaccine plasmid, pVHX-6, was administered intraepidermally to mice, followed by challenge in a lethal mouse model, the level of protection obtained ranged from 50 to 100% amongst three strains of WEEV. Preliminary results suggest the protective immunity provided by the DNA vaccine appears to be a cell-mediated immune response, as elevated cytotoxic T lymphocyte activity was detected against the E2 protein in a T-cell proliferation assay. The efficacy results suggest a DNA vaccine may be a promising approach against WEE infection.

Intranasal immunization with liposome-encapsulated plasmid DNA encoding influenza virus hemagglutinin elicits mucosal, cellular and humoral immune responses

BACKGROUND

Influenza viral infections are a significant global public health concern due to the morbidity and mortality associated with acute respiratory disease, associated secondary complications and pandemic threat. Currently, the most effective preventative measure is an annual intramuscular (i.m.) injection of a trivalent vaccine. Intramuscular immunization induces strong systemic humoral responses but not mucosal immune responses which are important in the first line of defense against influenza.

OBJECTIVES

A plasmid encoding influenza A/PR/8/34 (H1N1) hemagglutinin (HA; pCI-HA10) was evaluated with respect to the mucosal, cellular and humoral immune responses generated and to its efficacy in protection against a challenge with a lethal dose of influenza.

STUDY DESIGN

BALB/c mice were immunized with pCI-HA10 DNA or liposome-encapsulated pCI-HA10 by either an intranasal (i.n.) or i.m. route. Sera and bronchoalveolar lavage (BAL) fluid were collected at various times and evaluated for HA-specific IgG and IgA antibodies and T cells, isolated from draining lymph nodes and spleens, were analyzed for their proliferative ability. Immunized mice were challenged with a lethal dose (5LD(50)) of influenza and monitored for survival.

RESULTS AND CONCLUSIONS

Intranasal immunization with liposome-encapsulated pCI-HA10 stimulated both IgG and IgA humoral responses and increased IgA titers in BAL fluid, whereas immunization with naked pCI-HA10 had no effect on the antibody response. Intramuscular immunization with both naked and liposome-encapsulated pCI-HA10 elevated serum IgG levels, but had no effect on IgA levels in either the serum or BAL fluid. Both i.n. and i.m. administration of HA vaccine (naked and liposome-encapsulated) elicited T cell proliferative responses. These results suggest that i.n. administration of liposome-encapsulated HA-encoding DNA is effective at eliciting mucosal, cellular and humoral immune responses. Mice immunized i.n. were able to withstand a lethal challenge of influenza virus, confirming that the immune responses mediated by the vaccine were protective.

Characteristics of six newborn infants with postnatal findings of severe intracranial haemorrhage

OBJECTIVE

The objective of this study was to study the characteristics of newborn infants with postnatal findings of severe neonatal intracranial haemorrhage.

METHODS

All the records of babies who underwent surgery from 1997 to 2002 for intracranial haemorrhage were reviewed. These were correlated with their antenatal records to see if fetal intracranial haemorrhage had been detected at the 20 weeks' screening scan or any other incidental scan e.g. growth scan. The perinatal records were also reviewed to see if there was associated birth trauma such as instrumentation or obstetric manoeuvres at delivery.

RESULTS

Six cases of severe intracranial haemorrhage were diagnosed postnatally. Of these, only 1 case was detected antenatally on ultrasound scan. None of the cases were due to birth trauma. Three babies were found to have clotting factor deficiency. One of them subsequently developed cerebral palsy. One baby was diagnosed to have alloimmune thrombocytopenia. One case underwent an emergency Caesarean section for non-reassuring fetal status. Extensive intracranial haemorrhage, attributed to hypoxia, was found. The baby died.

CONCLUSIONS

Our study suggests that neonatal intracranial haemorrhages are not exclusively due to birth trauma. The study also shows that fetal intracranial haemorrhage may not be detected antenatally by the routine practice. The causes in our study included clotting deficiency, alloimmune thrombocytopenia and hypoxia.

Therapeutic efficacy of "nubiotics" against burn wound infection by Pseudomonas aeruginosa

"Nubiotics" are a novel class of proprietary protonated nucleic acid-based drugs shown to have potent in vitro antibacterial activities against a number of gram-positive and gram-negative bacteria. These nubiotics are evaluated here for their in vivo therapeutic efficacy for the treatment of burn wound infection caused by Pseudomonas aeruginosa. To achieve this, a burn wound infection model was established in mice by using a highly pathogenic burn wound clinical isolate of P. aeruginosa. Lethal doses of the bacteria were determined for two routes of infection (subcutaneous and topical), representing systemic and local forms of infection, respectively. Using this infection model, treatment with nubiotics by various routes of drug administration was evaluated and optimized. A total of 12 nubiotics and their analogues were tested and of these, Nu-2, -3, -4, and -5 were found to be extremely efficacious in the postexposure treatment of burn wound infection (60 to 100% survival rates versus 0% for untreated control [P < 0.05]). These nubiotics were effective when given either systemically by intravenous and/or subcutaneous administration or given locally to the affected site in the skin by topical application. Treatment by these two routes resulted in almost 100% survival rates and complete eradication of the bacteria from infection sites in the livers, spleens, and blood. These nubiotics were found to be as effective as intravenously administered ciprofloxacin, a potent and broad-spectrum fluoroquinolone. These results suggest that nubiotics may be a promising and effective approach for the treatment of burn wound infection caused by P. aeruginosa.

Liposome delivery of ciprofloxacin against intracellular Francisella tularensis infection

The effect of liposome delivery on the controlled release and therapeutic efficacy of ciprofloxacin against intracellular Francisella tularensis infection in vivo was evaluated in this study. Ciprofloxacin was encapsulated in small unilamellar vesicles by a remote loading procedure using an ammonium sulfate gradient. This procedure produced uniform sized liposomes (100 nm) with an entrapment rate of 90+/-3.5%. Following administration of unencapsulated or liposome-encapsulated ciprofloxacin by intravenous injection or aerosol inhalation, levels of ciprofloxacin in sera, lungs, liver and spleen were determined using 14C-ciprofloxacin as radiotracer for ciprofloxacin. Intravenous injection of liposome-encapsulated ciprofloxacin resulted in higher serum levels of drug in serum, as well as increased drug retention in lungs, liver and spleen, compared to that of free encapsulated drug. Aerosol administration of liposome-encapsulated ciprofloxacin by jet nebulization resulted in significantly higher drug levels and prolonged drug retention in the lower respiratory tract compared to the free drug. Aerosol inhalation of liposome-encapsulated ciprofloxacin, given either prophylactically or therapeutically, provided complete protection to mice against a pulmonary lethal infection model of F. tularensis. In contrast, ciprofloxacin given in its free form, was ineffective. These results suggest that liposome encapsulation of ciprofloxacin enhances drug delivery to the primary site of infection and results in increasing therapeutic efficacy against F. tularensis.

A novel approach to the pulmonary delivery of liposomes in dry powder form to eliminate the deleterious effects of milling

The effect of lyophilization and jet-milling on liposome integrity was investigated as a function of their ability to retain the encapsulated model drug on reconstitution of the dry products. The encapsulation efficiencies of the lyophilized and jet-milled formulations were determined at various concentrations of lactose. Lyophilization resulted in considerable leakage of the model drug at lower concentrations of lactose, and jet-milling further augmented the leakage for all the lyophilized formulations, with optimum retention obtained for formulations containing at least 10:1 molar ratio of lactose/lipid. In an attempt to overcome the deleterious effects of lyophilization and jet-milling, the feasibility of formulating phospholipid-based powders that result in spontaneous formation of liposomes in an aqueous environment has been investigated. Partitioning of three model drugs (viz., ciprofloxacin, CM3 peptide, and salbutamol sulfate) between the aqueous phase and spontaneously formed liposomes was determined in terms of encapsulation efficiency. The effects of several parameters, including lactose concentration, lipid composition, and lipid concentration on the encapsulation efficiency of these model drugs were investigated. The spontaneous formation of liposomes on dispersion of phospholipid-based powder formulations was further evidenced by freeze-fracture scanning electron microscopy. This novel approach for the delivery of liposomes in dry powder form appears promising because lyophilization is not involved and jet-milling of these powder formulations did not impact encapsulation efficiency. Jet-milled phospholipid-based powder formulations showed high encapsulation efficiencies of 96.2 +/- 1.4% for ciprofloxacin, 100% for CM3 peptide, and 45.3 +/- 3.1% for salbutamol sulfate compared with a high amount of leakage (> 50%) observed due to jet-milling of lyophilized liposome formulations encapsulating ciprofloxacin.

Fetal congenital complete heart block: prophylaxis with intravenous gammaglobulin and treatment with dexamethasone

We report a case of complete fetal heart block in a 35-year-old Chinese woman known to be positive for anti-SSA/Ro and anti-SSB/La antibodies. She had fetal hydrops leading to intrauterine death in her first pregnancy Prophylactic intravenous immunoglobulin, given at 14 and 18 weeks' gestation, as well as oral dexamethasone, commenced at 24 weeks' gestation, allowed continuation of the pregnancy until 34 completed weeks of gestation. An external pacemaker was inserted in the baby on the first day of life. Two-and-a-half months later, a permanent pacemaker was inserted.

DNA vaccination against respiratory influenza virus infection

DNA vaccination using plasmid encoding the hemagglutinin (HA) gene of influenza A/PR/8/34 virus to induce long-lasting protective immunity against respiratory infection was evaluated in this study. Using liposomes as carriers, the efficacy of DNA vaccines was determined using a lethal influenza infection model in mice. Mice immunized intranasally or intramuscularly with liposome-encapsulated pCI plasmid encoding HA (pCI-HA10) were completely protected against an intranasal 5 LD(50) influenza virus challenge. Mice immunized with liposome-encapsulated pCI-HA10, but not naked pCI-HA10, by intranasal administration were found to produce high titers of serum IgA. These results suggest DNA vaccines encapsulated in liposomes are efficacious in inducing complete protective immunity against respiratory influenza virus infection.

Immunoprophylactic strategies against respiratory influenza virus infection

The objective of this report is to evaluate the prophylactic efficacy of liposome-mediated immunotherapy for prevention of respiratory influenza virus infection in mice. Antiviral antibody, interferon-gamma and poly (ICLC) were encapsulated in liposomes and they were evaluated for their ability to induce protective immunity against lethal influenza infection. Passive immunization using liposome-encapsulated antiviral antibody was found to offer complete protection against the virus challenge. However, this pretreatment must be administered within 24 h prior to virus challenge to be protective. Pretreatment with liposome-encapsulated interferon-gamma was found to stimulate cellular immune responses, but the protection is partial. Immunoprophylaxis using liposome-encapsulated double-stranded (ds) RNA poly (ICLC) provided complete and longer-lasting protection against influenza infection. These results suggest liposome-mediated immunoprophylactic approaches are effective in the prevention of respiratory influenza virus infection.

Pharmacokinetics study of a novel chimeric single-chain variable fragment antibody against western equine encephalitis virus

A novel recombinant single-chain fragment variable (scFv) antibody against western equine encephalitis (WEE) virus has been previously constructed and partially characterized. The RS10B5huFc antibody was made by fusing an anti-WEE scFv to a human heavy-chain IgG1 constant region. The RS10B5huFc antibody was functional in binding to WEE virus in enzyme-linked immunosorbent assays (ELISAs), and the Fc domain of the antibody was capable of effector functions, such as binding to protein G and human complement. In this study, the RS10B5huFc antibody was further characterized by BIAcore analyses and was found to possess a binding affinity to a WEE virus epitope (K[D] = 9.14 x 10(-6) M), 4.5-fold lower than its parental mouse monoclonal antibody (MAb) 10B5 E7E2 (K[D] = 2 x 10(-6) M). No cross-reactivity was found between the RS10B5huFc antibody and three other alphaviruses (Sindbis virus [SIN], Venezuelan equine encephalitis [VEE] virus, and eastern equine encephalitis [EEE] virus). Pharmacokinetics studies showed that the RS10B5huFc antibody (free and encapsulated) was found to be retained in the lungs of mice for greater than 48 h when administered intranasally. In contrast, when administered intramuscularly to mice, the RS10B5huFc antibody was not detected in the lungs and only found in the liver and kidneys.

Repeated use of two Chlorella species, C. vulgaris and WW1 for cyclic nickel biosorption

Two living Chlorella species were used to remove nickel from solution containing 30 micrograms Ni ml-1 in 10 successive cycles. The present study also examined the continued viability of these two algal species after repeated exposure to nickel. The two species of Chlorella were Chlorella vulgaris (commercially available) and WW1 (indigenous species isolated from domestic sewage and was tentatively identified as Chlorella miniata). The nickel removal percentage of WW1 cells was maintained at around 85% in the first five cycles, then declined slightly from the fifth cycle onwards, and finally achieved around 70% removal at the end of the 10th cycle. On the contrary, the removal efficiency of C. vulgaris declined from 50 to 30% during the 10 cycles of nickel bisorption. At the end of these 10 successive cycles, WW1 accumulated a substantial amount of Ni2+ (the cumulative cellular Ni concentration was 0.92% dry w.), while the value was only 0.17% in the case of C. vulgaris. These results suggest that the local isolate, WW1, had more consistent and satisfactory ability for removing Ni than the commercial C. vulgaris. Both algal species were still capable of dividing after each nickel treatment cycle, suggesting that the cells were not killed even when significant amounts of nickel were adsorbed/absorbed. However, Ni exposure adversely affected the physiological activity of algal cells as reflected by the decline in division rate and chlorophyll-a activity in both species. Such negative effects became more obvious as the number of cyclic treatments was increased. Nevertheless, WW1 cells appeared to recover from nickel treatment when re-cultivated in commercial medium for 2 weeks.

Effects of liposome-encapsulated ciprofloxacin on phagocytosis, nitric oxide and intracellular killing of Staphylcoccus aureus by murine macrophages

The effects of liposome-encapsulated ciprofloxacin on phagocytosis, nitric oxide production and intracellular killing of Staphylococcus aureus in murine macrophages were evaluated in this study. Mice were pretreated with three daily doses of liposome-encapsulated ciprofloxacin (45 mg/kg body weight/dose, intraperitoneal injection). At day 3 post drug administration, peritoneal macrophages were harvested by peritoneal lavage, and the phagocytic activity of the macrophages was determined by a chemiluminescence assay using opsonized zymosan particles. The phagocytic activity was found to be 7-fold higher in the liposome-encapsulated ciprofloxacin-treated group when compared to the untreated control group. For S. aureus-infected macrophages incubated with liposomes containing subinhibitory concentrations of ciprofloxacin (0.05 to 0.25 microg/mL), there were significant increases (up to 40 microM) in the levels of nitrite (NO2-, an end product of nitric oxide synthesis), and concommitant decreases (2-3 log) in the intracellular concentrations of S. aureus. Peak nitrite levels (20-40 microM) were produced when concentrations of liposome-encapsulated ciprofloxacin used were 0.1 to 0.25 microg/mL. These results suggest that liposome-encapsulated ciprofloxacin may have profound effects on the immunological functions of macrophages.

Revegetation of lagoon ash using the legume species Acacia auriculiformis and Leucaena leucocephala

A greenhouse study was conducted to evaluate the potential use of two legume species, Acacia auriculiformis and Leucaena leucocephala for growth on ameliorated lagoon ash with or without nitrogen (N(2))-fixing bacteria inoculation. Even though amendments of 30% (w/w) vermiculite or with sewage sludge compost were added to improve the chemical and physical limitations of lagoon ash, significant suppressions in biomass and plant nutrient content were found with ameliorated lagoon ash in comparison to an agricultural soil. The high proportion of clay-sized (<53 microm) ash particles limited root growth. In addition, heavy metal toxicity was a possible factor contributing to poor seedling growth. Higher plant productivity resulted from the sewage sludge compost-amended lagoon ash than with vermiculite due to a greater contribution of plant nutrients in the compost. Nodulation was inhibited in ameliorated lagoon ash but not in agricultural soil. High pH and electrical conductivity and elevated toxic metals may be important parameters that limit bacterial activity. Both species showed potential to establish on amended lagoon ash, with Acacia auriculiformis being the best adapted.

Sustained drug release characteristics of biodegradable composite poly(d,l)lactic acid-poly(l)lactic acid microcapsules containing ciprofloxacin

Ciprofloxacin polylactic microcapsules were prepared by the phase separation process. Two types of polylactic acid, poly(d,l)lactic acid and poly(l)lactic acid were combined as membrane materials to prevent the aggregation which happened frequently in the phase separation process. The polymer compositions of the microcapsules can influence the release rate of Ciprofloxacin. The optimal release rate of the drug can be obtained by modifying microcapsule compositions. Poly(d,l)lactic acid is superior in slowing the rate of drug release than poly(l)lactic acid. However, poly(l)lactic acid is necessary in the preparation of the microcapsules to prevent aggregation.

Biodegradable polylactic acid nanocapsules containing ciprofloxacin: preparation and characterization

Nanocapsules have been studied as carriers to deliver different types of drugs into macrophages. Many studies have shown that the nanocapsules can enhance the biological response of the drugs. In this study, we prepared ciprofloxacin nanocapsules with polylactic acid. The ciprofloxacin is an antibacterial agent. The ciprofloxacin nanocapsules prepared have a means diameter of 168 nm. In phosphate buffer at pH 7.4, high encapsulation rate was obtained. The nanocapsules with high encapsulation rate can also be made from ciprofloxacin base.

Antibody response in goats vaccinated with liposome-adjuvanted Clostridium perfringens type D epsilon toxoid

A trial was performed using 20 goats to evaluate the antibody responses to a liposome-adjuvanted Clostridium perfringens epsilon toxoid vaccine (LIPV). The antibody response was compared with those produced by epsilon toxoid vaccines prepared using aluminium hydroxide (ALV) and incomplete Freud's adjuvant (FAV). The animals were allocated to four groups at the beginning of the trial. The animals in group 1 were vaccinated with ALV, while the animals in group 2 received FAV and those in groups 3 and 4 were vaccinated with LIPV. The animals in groups 1 to 3 received three doses of the corresponding vaccine at intervals of three weeks, while those in group 4 received only 1 dose of vaccine at the beginning of the trial. A blood sample was obtained from all the goats at the beginning of the trial and then weekly for 8 weeks. The samples were analysed for epsilon toxoid antibodies by an indirect ELISA technique. No major clinical abnormalities were observed in the animals after vaccination, with the exception of those that received the FAV, which experienced transient lameness. The highest antibody response was observed in the animals vaccinated with FAV, but they presented moderate to severe inflammatory tissue reactions at the injection site. Moderately high antibody responses were obtained with the ALV, with which only minor local reactions were observed. No significant antibody responses were obtained with the LIPV, nor were local reactions observed.

Liposome-mediated immunotherapy against respiratory influenza virus infection using double-stranded RNA poly ICLC

The use of liposome delivery technology to enhance the antiviral activity of poly ICLC (an immunomodulating dsRNA) while decreasing its intrinsic toxicity is evaluated in this study. The antiviral efficacies of free and liposome-encapsulated poly ICLC were evaluated and compared using a lethal respiratory influenza A virus infection in mice. The toxicity profiles of free and liposome-encapsulated poly ICLC were compared by determining the extent of hypothermia and loss in body weights in mice pretreated with these drugs. Poly ICLC was encapsulated in cationic liposomes prepared by the freeze drying method. To determine the antiviral efficacies of free and liposome-encapsulated poly ICLC, mice were intranasally pretreated with two doses of poly ICLC (free or liposomal, 1 mg/kg/dose) given 48 h apart. At various times post pretreatment, mice were intranasally challenged with 10 LD50 mouse-adapted influenza A/PR/8 (H1N1) virus. The survival rates of the mice were determined at day 14 post infected and compared to the untreated control mice. Results indicate mice pretreated with liposome-encapsulated poly ICLC within 3 weeks prior to virus challenge were completely protected (100% survival compared to 0% for the untreated control group, p < 0.001), while window of protection provided by free unencapsulated poly ICLC was 12 days. When the toxicity profiles of free and liposome-encapsulated poly ICLC were compared, it was found that hypothermia and body weight loss induced by poly ICLC were either completely mitigated or significantly reduced in mice given equivalent doses of poly ICLC in the liposome-encapsulated form. These results suggest that liposomes are an excellent drug carrier for poly ICLC, that liposome-encapsulated poly ICLC may provide a safe and effective immunotherapeutic approach for the prevention of respiratory influenza virus infections.

Preparation of polylactic acid microcapsules containing ciprofloxacin

Microcapsules have been used as drug delivery systems in the pharmaceutical field for sustained or controlled release of drug, and for artificial cells and organs. Biodegradable polymers, especially polylactic acid, have been widely used in this field. In this study, an attempt was made to develop a new method to prepare polylactic acid microcapsules for drug delivery. The biodegradable polylactic acid microcapsules were made by the phase separation process: two types of polylactic acid, poly[(D,L)lactic acid] and poly[(L)lactic acid] were combined as the membrane material. Because of the difference of the crystal properties of the two polymers, the aggregation which happens frequently in the phase separation process was prevented. As a model drug, Ciprofloxacin was encapsulated in the polylactic acid microcapsules.

Aerosol delivery of liposome-encapsulated ciprofloxacin: aerosol characterization and efficacy against Francisella tularensis infection in mice

The aerosol delivery of liposome-encapsulated ciprofloxacin by using 12 commercially available jet nebulizers was evaluated in this study. Aerosol particles containing liposome-encapsulated ciprofloxacin generated by the nebulizers were analyzed with a laser aerodynamic particle sizer. Mean mass aerodynamic diameters (MMADs) and geometric standard deviations (GSDs) were determined, and the drug contents of the sampling filters from each run onto which aerosolized liposome-encapsulated ciprofloxacin had been deposited were analyzed spectrophotometrically. The aerosol particles of liposome-encapsulated ciprofloxacin generated by these nebulizers ranged from 1.94 to 3.5 microm, with GSDs ranging from 1.51 to 1.84 microm. The drug contents of the sampling filters exposed for 1 min to aerosolized liposome-encapsulated ciprofloxacin range from 12.7 to 40.5 microg/ml (0.06 to 0.2 mg/filter). By using the nebulizer selected on the basis of most desirable MMADs, particle counts, and drug deposition, aerosolized liposome-encapsulated ciprofloxacin was used for the treatment of mice infected with 10 times the 50% lethal dose of Francisella tularensis. All mice treated with aerosolized liposome-encapsulated ciprofloxacin survived the infection, while all ciprofloxacin-treated or untreated control mice succumbed to the infection (P < 0.001). These results suggest that aerosol delivery of liposome-encapsulated ciprofloxacin to the lower respiratory tract is feasible and that it may provide an effective therapy for the treatment of respiratory tract infections.