Viral respiratory infections due to rhinoviruses: current knowledge, new developments

Systemic Steroids for Otolaryngology-Head and Neck Surgery Disorders: An Evidence-Based Primer for Clinicians

OBJECTIVE

To offer pragmatic, evidence-informed guidance on the use of systemic corticosteroids (SCS) for common otolaryngologic disorders.

DATA SOURCES

PubMed, Cochrane Library, and American Academy of Otolaryngology-Head and Neck Surgery Foundation clinical practice guidelines.

REVIEW METHODS

A comprehensive search of published literature through November 2021 was conducted on the efficacy of SCS, alone or in combination with other treatments, for managing disorders in otolaryngology and the subdisciplines. Clinical practice guidelines, systematic reviews, and randomized controlled trials, when available, were preferentially retrieved. Interventions and outcomes of SCS use were compiled to generate summary tables and narrative synthesis of findings.

CONCLUSIONS

Evidence on the effectiveness of SCS varies widely across otolaryngology disorders. High-level evidence supports SCS use for Bell's palsy, sinonasal polyposis, and lower airway disease. Conversely, evidence is weak or absent for upper respiratory tract infection, eustachian tube dysfunction, benign paroxysmal positional vertigo, adenotonsillar hypertrophy, or nonallergic rhinitis. Evidence is indeterminate for acute laryngitis, acute pharyngitis, acute sinusitis, angioedema, chronic rhinosinusitis without polyps, Ménière's disease, postviral olfactory loss, postoperative nerve paresis/paralysis, facial pain, and sudden sensorineural hearing loss.

IMPLICATIONS FOR PRACTICE

Clinicians should bring an evidence-informed lens to SCS prescribing to best counsel patients regarding the risks, anticipated benefits, and limited data on long-term effects. Alternate routes of corticosteroid administration-such as sprays, drops, inhalers, and intralesional injections-may be preferable for many disorders, particularly those that are self-limited or require a prolonged duration of therapy. Prudent use of SCS reduces the risk of medication-related adverse effects. Clinicians who are conversant with high-level evidence can achieve optimal outcomes and stewardship when prescribing SCS.

The effect of health education on knowledge and behavior toward respiratory infectious diseases among students in Gansu, China: a quasi-natural experiment

BACKGROUND

The respiratory infectious diseases (RID) threaten the health and life quality of school students. However, previous related studies were insufficient in research design and method applied. This study aimed to evaluate the effect of health education on the knowledge and behavior of students toward RID through difference-in-difference (DID) analysis in Gansu, China.

METHODS

In 2015-2016, a one-year health education program in Gansu, China was conducted. The intervention group contained 1064 students before and 1001 students after the health education (2015 and 2016, respectively). The control group contained 1018 and 1001 students, respectively. The health education, including playing promotional cartoons, developing lectures, giving out handbook copies and making hand copy and blackboard newspapers, and publicity columns on RID, were conducted monthly from 2015 to 2016 in intervention group. The data were collected before and after the health education program with a questionnaire on the students' knowledge and preventive behaviors regarding RID. The ×2 and t tests were performed to compare the accuracy rate and scores for RID knowledge and behavior of the two groups. DID estimation was conducted to evaluate the effect of health education on RID knowledge and behavior while controlling the non- equilibrium variables.

RESULTS

After the health education program, the accuracy rate and scores of most items in the intervention group were significantly higher than those in the control group (P < 0.05) except for item k9 "What methods can prevent flu?". The DID results wherein the demographics- age, nationality, and household register were controlled showed that health education significantly improved the accuracy rate of RID knowledge by 5.2-63.9% for most items, although the accuracy rates of items k2 "What's the transmission way of the mumps?" and k9 were significantly decreased by 36.8 and 12.0%. The health education significantly improved the score of knowledge by 155.2% (P < 0.001) and the accuracy rate of all items of RID behavior by 2.9-51.5% except for item b3 "If you have phlegm, how do you usually deal with it?". In addition, the health education also significantly improved the score of behavior toward RID of the sampled students by 138.2% (P < 0.001).

CONCLUSION

The results of this study show that health education seemed to increase the RID knowledge and behavior of students. It is recommended that the health education should be enhanced and popularized in schools of China, and RID transmission routes and prevention methods should attract more attention.

Human Type I Interferon Antiviral Effects in Respiratory and Reemerging Viral Infections

Type I interferons (IFN-I) are a group of related proteins that help regulate the activity of the immune system and play a key role in host defense against viral infections. Upon infection, the IFN-I are rapidly secreted and induce a wide range of effects that not only act upon innate immune cells but also modulate the adaptive immune system. While IFN-I and many IFN stimulated genes are well-known for their protective antiviral role, recent studies have associated them with potential pathogenic functions. In this review, we summarize the current knowledge regarding the complex effects of human IFN-I responses in respiratory as well as reemerging flavivirus infections of public health significance and the molecular mechanisms by which viral proteins antagonize the establishment of an antiviral host defense. Antiviral effects and immune modulation of IFN-stimulated genes is discussed in resisting and controlling pathogens. Understanding the mechanisms of these processes will be crucial in determining how viral replication can be effectively controlled and in developing safe and effective vaccines and novel therapeutic strategies.

Self-Care for Common Colds: The Pivotal Role of Vitamin D, Vitamin C, Zinc, and Echinacea in Three Main Immune Interactive Clusters (Physical Barriers, Innate and Adaptive Immunity) Involved during an Episode of Common Colds-Practical Advice on Dosages and on the Time to Take These Nutrients/Botanicals in order to Prevent or Treat Common Colds

Maintaining a normal healthy immune defense system lowers the incidence and/or the severity of symptoms and/or the duration of common cold (CC). Physical barriers and innate and adaptive immunity have been involved during a CC episode. Vitamins C and D, zinc, and Echinacea have evidence-based efficacy on these immune system barriers. This review includes 82 eligible studies to consider the preventive role of these nutrients in immune clusters and in CC to provide advice on dosage and assumption of these nutrients. Regarding vitamin C, regular supplementation (1 to 2 g/day) has shown that vitamin C reduces the duration (in adults by 8%, in children by 14%) and the severity of CC. Considering zinc, the supplementation may shorten the duration of colds by approximately 33%. CC patients may be instructed to try zinc within 24 hours of onset of symptoms. As for vitamin D, the supplementation protected against CC overall, considering baseline levels and age. Patients with vitamin D deficiency and those not receiving bolus doses experienced the most benefit. Regarding Echinacea, prophylactic treatment with this extract (2400 mg/day) over 4 months appeared to be beneficial for preventing/treating CC. In conclusion, the current evidence of efficacy for zinc, vitamins D and C, and Echinacea is so interesting that CC patients may be encouraged to try them for preventing/treating their colds, although further studies are needed on this topic.

Human rhinovirus in experimental infection after peroral Lactobacillus rhamnosus GG consumption, a pilot study

BACKGROUND

Data has emerged on possible beneficial effects of probiotics in respiratory tract viral infections, but it is unclear if the promising positive effects evidenced are due to a reduced viral load during infections. The aims of this work were to investigate the effect of peroral probiotic Lactobacillus rhamnosus GG (American Type Culture Collection [ATCC], Accession No. 53103) consumption on human rhinovirus (HRV) load in nasopharyngeal lavage samples in experimental HRV infection, and to correlate viral load to clinical symptoms.

METHODS

Intranasal HRV A39 inoculation was performed on 59 adults, who had consumed juice enriched with live or heat-inactivated L. rhamnosus GG or control juice for 3 weeks prior to inoculation in a randomized, controlled, pilot trial setting. Nasopharyngeal lavage samples and symptom data were analyzed on day 0 before inoculation, and on days 2 and 5. Samples were subjected to quantitative HRV detection by polymerase chain reaction (PCR).

RESULTS

Before inoculation 9 of 59 (15%) samples presented with another HRV strain than the studied A39. There was a tendency toward the lowest HRV loads in the L. rhamnosus GG groups and the highest in placebo group (log10 copies/mL, 95% confidence interval [CI], 6.20 [5.18 to 7.40] in live, 6.30 [4.91 to 7.08] in inactivated L. rhamnosus GG, and 7.25 [5.81 to 7.52] in placebo group, p = 0.57 in day 2) in the wild-type excluded population. The HRV load positively correlated with the symptom scores on days 2 and 5 (correlation coefficient 0.61 [p < 0.001] and 0.28 [p = 0.034], respectively).

CONCLUSION

Results did not show statistical differences in viral loads in subjects using L. rhamnosus GG when compared to placebo. HRV load positively correlated with the total symptom scores.

Evidence of nosocomial transmission of human rhinovirus in a neonatal intensive care unit

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We detected an outbreak of nosocomial human rhinovirus C in our neonatal intensive care unit.

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Although the outbreak only consisted of 2 cases, it emphasizes the importance of hand hygiene in a neonatal intensive care unit to prevent the spread of infectious diseases to a susceptible population.

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Laboratory techniques, such as respiratory panel polymerase chain reaction, improve the efficiency of test results, allowing clinicians the ability to detect outbreaks and detect them earlier.

Nosocomial respiratory infections cause significant morbidity and mortality, especially among the extremely susceptible neonatal population. Human rhinovirus C is a common viral respiratory illness that causes significant complications in children <2 years old. We describe a nosocomial outbreak of human rhinovirus C in a level II-III neonatal intensive care unit in an urban public safety net hospital.

Rhinovirus stimulated IFN-α production: how important are plasmacytoid DCs, monocytes and endosomal pH?

Human rhinovirus (HRV) infection is a major cause of asthma exacerbations, which appears to be linked to a defective innate immune response to infection. Although the type I interferons (IFN-α and IFN-β) have a critical role in protecting against most viral infections, the cells responsible for IFN production in response to HRV and the relative importance of pattern recognition receptors located in endosomes has not been fully elucidated. In the current study we demonstrate that, using intracellular flow cytometry, >90% of the IFN-α-producing cells in human blood mononuclear cells following HRV16 exposure are plasmacytoid dendritic cells, whereas monocytes and myeloid dendritic cells contribute only 10% and <1%, respectively, of the IFN-α production. Bafilomycin and chloroquine, agents that inhibit the function of endosomal toll-like receptors (TLRs), significantly reduced the capacity of TLR3-, TLR7- and TLR-9-stimulated cells to produce IFN-α and the IFN-induced chemokine CXCL10 (IP-10). In contrast, only bafilomycin (but not chloroquine) effectively suppressed HRV16-stimulated IFN-α and IP-10 production, whereas neither bafilomycin or chloroquine inhibited HRV16-stimulated interleukin-6 release. Attempts to block IFN-α production with commercially available TLR-specific oligonucleotides were unsuccessful due to major ‘off-target' effects. These findings suggest that among circulating haemopoietic cells, plasmacytoid dendritic cells and TLRs located within endosomes are critical for inducing efficient IFN-I production in response to HRVs.

Corticosteroids for the common cold

BACKGROUND

The common cold is a frequent illness, which, although benign and self limiting, results in many consultations to primary care and considerable loss of school or work days. Current symptomatic treatments have limited benefit. Corticosteroids are an effective treatment in other upper respiratory tract infections and their anti-inflammatory effects may also be beneficial in the common cold. This updated review has included one additional study.

OBJECTIVES

To compare corticosteroids versus usual care for the common cold on measures of symptom resolution and improvement in children and adults.

SEARCH METHODS

We searched Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 4), which includes the Acute Respiratory Infections (ARI) Group's Specialised Register, the Database of Reviews of Effects (DARE) (2015, Issue 2), NHS Health Economics Database (2015, Issue 2), MEDLINE (1948 to May week 3, 2015) and EMBASE (January 2010 to May 2015).

SELECTION CRITERIA

Randomised, double-blind, controlled trials comparing corticosteroids to placebo or to standard clinical management.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality. We were unable to perform meta-analysis and instead present a narrative description of the available evidence.

MAIN RESULTS

We included three trials (353 participants). Two trials compared intranasal corticosteroids to placebo and one trial compared intranasal corticosteroids to usual care; no trials studied oral corticosteroids. In the two placebo-controlled trials, no benefit of intranasal corticosteroids was demonstrated for duration or severity of symptoms. The risk of bias overall was low or unclear in these two trials. In a trial of 54 participants, the mean number of symptomatic days was 10.3 in the placebo group, compared to 10.7 in those using intranasal corticosteroids (P value = 0.72). A second trial of 199 participants reported no significant differences in the duration of symptoms. The single-blind trial in children aged two to 14 years, who were also receiving oral antibiotics, had inadequate reporting of outcome measures regarding symptom resolution. The overall risk of bias was high for this trial. Mean symptom severity scores were significantly lower in the group receiving intranasal steroids in addition to oral amoxicillin. One placebo-controlled trial reported the presence of rhinovirus in nasal aspirates and found no differences. Only one of the three trials reported on adverse events; no differences were found. Two trials reported secondary bacterial infections (one case of sinusitis, one case of acute otitis media; both in the corticosteroid groups). A lack of comparable outcome measures meant that we were unable to combine the data.

AUTHORS' CONCLUSIONS

Current evidence does not support the use of intranasal corticosteroids for symptomatic relief from the common cold. However, there were only three trials, one of which was very poor quality, and there was limited statistical power overall. Further large, randomised, double-blind, placebo-controlled trials in adults and children are required to answer this question.

Perceived Immune Status and Sleep: A Survey among Dutch Students

Reduced immune functioning may have a negative impact on sleep and health, and vice versa. A survey among Dutch young adults (18–35 years old) was administered to collect information on perception of reduced immunity and its relationship to sleep disorders, sleep duration, and quality. Sleep disorders were assessed with the SLEEP-50 questionnaire subscales of sleep apnea, insomnia, circadian rhythm disorder, and daily functioning. Dutch young adults (N = 574) completed the survey. Among them, subjects (N = 209; 36.4%) reported perceived reduced immunity. Relative to those with a normal immune status, subjects reporting reduced immunity had significantly higher scores (p = 0.0001) on sleep apnea (2.6 versus 3.6), insomnia (5.1 versus 6.8), and circadian rhythm disorder (2.1 versus 2.7). Subjects reporting reduced immunity also had significantly poorer daily functioning scores (5.4 versus 7.6, p = 0.0001). No differences were observed in total sleep time, but those reporting reduced immunity had significantly poorer ratings of sleep quality (6.8 versus 7.2, p = 0.0001). Our findings suggest that perceived reduced immunity is associated with sleep disturbances, impaired daily functioning, and a poorer sleep quality. Experimental studies including the assessment of immune biomarkers and objective measures of sleep (polysomnography) should confirm the current observations.

Efficacy of a carrageenan nasal spray in patients with common cold: a randomized controlled trial

Background

The common cold is the most widespread viral infection in humans. Iota-carrageenan has previously shown antiviral effectiveness against cold viruses in clinical trials. This study investigated the efficacy of a carrageenan-containing nasal spray on the duration of the common cold and nasal fluid viral load in adult patients.

Methods

In a randomized, double-blind, placebo-controlled trial, 211 patients suffering from early symptoms of the common cold were treated for seven days. Application was performed three times daily with either a carrageenan-supplemented nasal spray or saline solution as placebo with an overall observation period of 21 days. The primary endpoint was the duration of disease defined as the time until the last day with symptoms followed by all other days in the study period without symptoms. During the study, but prior unblinding, the definition of disease duration was adapted from the original protocol that defines disease duration as the time period of symptoms followed by 48 hours without symptoms.

Results

In patients showing a laboratory-confirmed cold virus infection and adherence to the protocol, alleviation of symptoms was 2.1 days faster in the carrageenan group in comparison to placebo (p = 0.037). The primary endpoint that had been prespecified but was changed before unblinding was not met. Viral titers in nasal fluids showed a significantly greater decrease in carrageenan patients in the intention-to-treat population (p = 0.024) and in the per protocol population (p = 0.018) between days 1 and 3/4.

Conclusions

In adults with common cold virus infections, direct local administration of carrageenan with nasal sprays reduced the duration of cold symptoms. A significant reduction of viral load in the nasal wash fluids of patients confirmed similar findings from earlier trials in children and adults.

Trial registration

Current Controlled Trials ISRCTN80148028

Efficacy and safety of Echinaforce® in respiratory tract infections

Echinaforce® is the standardised extract of Echinacea purpurea from Bioforce, Switzerland. Recent studies show immunomodulation and broad antiviral effects against respiratory tract viruses. Haemagglutinin and Neuraminidase are blocked. In contrast to Oseltamivir no resistance is caused by Echinaforce®. A randomised, double-blind, placebo-controlled study over four months confirms that Echinaforce® supports the immune resistance and acts directly against a series of viruses. Echinaforce® is efficacious and safe in respiratory tract infections for long-term and short-term prevention as well as for acute treatment.

Productive entry pathways of human rhinoviruses

Currently, complete or partial genome sequences of more than 150 human rhinovirus (HRV) isolates are known. Twelve species A use members of the low-density lipoprotein receptor family for cell entry, whereas the remaining HRV-A and all HRV-B bind ICAM-1. HRV-Cs exploit an unknown receptor. At least all A and B type viruses depend on receptor-mediated endocytosis for infection. In HeLa cells, they are internalized mainly by a clathrin- and dynamin-dependent mechanism. Upon uptake into acidic compartments, the icosahedral HRV capsid expands by ~4% and holes open at the 2-fold axes, close to the pseudo-3-fold axes and at the base of the star-shaped dome protruding at the vertices. RNA-protein interactions are broken and new ones are established, the small internal myristoylated capsid protein VP4 is expelled, and amphipathic N-terminal sequences of VP1 become exposed. The now hydrophobic subviral particle attaches to the inner surface of endosomes and transfers its genomic (+) ssRNA into the cytosol. The RNA leaves the virus starting with the poly(A) tail at its 3′-end and passes through a membrane pore contiguous with one of the holes in the capsid wall. Alternatively, the endosome is disrupted and the RNA freely diffuses into the cytoplasm.

Corticosteroids for the common cold

BACKGROUND

The common cold is a frequent illness, which, although benign and self-limiting, results in many consultations to primary care and considerable loss of school or work days. Current symptomatic treatments have limited benefit. Corticosteroids are an effective treatment in other upper respiratory tract infections and their anti-inflammatory effects may also be beneficial in the common cold.

OBJECTIVES

To compare corticosteroids versus usual care for the common cold on clinical response rates in children and adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2012, Issue 5 which includes the Acute Respiratory Infections (ARI) Group's Specialised Register, the Database of Reviews of Effects (DARE) 2012, Issue 4 and the NHS Health Economics Database 2012, Issue 5; MEDLINE (1948 to May week 2, 2012) and EMBASE (January 2010 to May 2012).

SELECTION CRITERIA

Randomised, double-blind, controlled trials comparing corticosteroids to placebo or to standard clinical management.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality. We were unable to perform meta-analysis and instead analysed results using narrative description of the available evidence.

MAIN RESULTS

We included two trials (253 participants). Both compared intranasal corticosteroids to placebo; no trials studied oral corticosteroids. No benefit of intranasal corticosteroids was demonstrated for duration or severity of symptoms. In one trial of 54 participants, the number of symptomatic days was 10.3 in the placebo group, compared to 10.7 in those using intranasal corticosteroids (P = 0.72). A second trial of 199 participants reported no significant differences in duration of symptoms. There were no differences reported in terms of: adverse events; complications (one case of sinusitis, one case of acute otitis media, both in corticosteroid groups); presence of rhinovirus in nasal aspirates; or treatment for secondary infections. Neither trial reported our primary outcome measure of percentage of participants with resolution at different time points. A lack of comparable outcome measures meant we were unable to combine the data.

AUTHORS' CONCLUSIONS

Current evidence does not support the use of intranasal corticosteroids for symptomatic relief from the common cold. However, there were only two trials and limited statistical power. Further large randomised placebo-controlled trials in adults and children are required to answer this question.

An outbreak of human rhinovirus species C infections in a neonatal intensive care unit

We describe an outbreak of human rhinovirus type C infection in 7 infants in our neonatal/pediatric intensive care unit. Five infants had clinically significant apneic episodes and 5 required increased oxygen or ventilatory support. Infants shed virus detectable by polymerase chain reaction for a median of 4 weeks.

Anti-tussive and bronchodilator mechanisms of action for the enaminone E121

AIMS

In this study, we investigated whether the enaminone, E121, has anti-tussive effects in a guinea pig model of cough, and if so, whether this effect is mediated via a central or peripheral site of action. We also assessed whether E121 has bronchodilator effects and the molecular mechanisms underlying any anti-tussive and/or bronchodilator effects.

MAIN METHODS

Whole body plethysmography was used to assess both cough and airway obstruction. A stereotaxic apparatus was used to administer drugs intracerebroventricularly (i.c.v.). Effects of E121 were examined in vitro on contractile effects in guinea pig bronchioles.

KEY FINDINGS

Pre-treatment of animals with E121 resulted in a significant inhibition in the citric acid-induced cough and airway obstruction compared to vehicle-pretreated animals. The K(ATP) antagonist, glibenclamide, significantly inhibited the anti-tussive and bronchoprotective effects of E121. Also, intra-tracheal administration of E121 resulted in a significant inhibition of both the citric acid-induced cough response and airway obstruction compared to vehicle-pretreated animals. By contrast, i.c.v. administration had no effect. Finally, E121 significantly inhibited carbachol-induced airway smooth muscle contractions, an effect that was reduced by both glibenclamide and propranolol. Interestingly, E121 enhanced histamine-induced cAMP release in human eosinophils although it did not directly elevate cAMP levels.

SIGNIFICANCE

The enaminone, E121, has anti-tussive and bronchodilatory effects and is topically, but not centrally, active. The anti-tussive mechanism of action of E121 seems to be K(ATP) channel dependent, whereas its bronchodilatory effects appear to be mediated via activation of both K(ATP) channels and β(2) receptors. Therefore, E121 may potentially represent a novel therapy for cough, particularly cough associated with airway obstruction.

Effects of Echinaforce® treatment on ex vivo-stimulated blood cells

The herb Echinacea purpurea, also called purple coneflower, is regarded as an immune modulator. This study examined changes in cytokine production in blood samples from 30 volunteers before and during 8-day oral administration with an ethanolic extract of fresh Echinacea purpurea (Echinaforce(®)). Daily blood samples were ex vivo stimulated by LPS/SEB or Zymosan and analysed for a series of cytokines and haematological and metabolic parameters. Treatment reduced the proinflammatory mediators TNF-α and IL-1β by up to 24% (p<0.05) and increased anti-inflammatory IL-10 levels by 13% (p<0.05) in comparison to baseline. This demonstrated a substantial overall anti-inflammatory effect of Echinaforce(®) for the whole group (n=28). Chemokines MCP-1 and IL-8 were upregulated by 15% in samples from subjects treated with Echinaforce(®) (p<0.05). An analysis of a subgroup of volunteers who showed low pre-treatment levels of the cytokines MCP-1, IL-8, IL-10 or IFN-γ (n=8) showed significant stimulation of these factors upon Echinaforce(®) treatment (30-49% increases; p<0.05), whereas the levels in subjects with higher pre-treatment levels remained unaffected. We chose the term "adapted immune-modulation" to describe this observation. Volunteers who reported high stress levels (n=7) and more than 2 colds per year experienced a significant transient increase in IFN-γ upon Echinaforce(®) treatment (>50%). Subjects with low cortisol levels (n=11) showed significant down-regulation of the acute-phase proteins IL1-β, IL-6, IL-12 and TNF-α by Echinaforce(®) (range, 13-25%), while subjects with higher cortisol levels showed no such down-regulation. This is the first ex vivo study to demonstrate adapted immune-modulation by an Echinacea preparation. While Echinaforce(®) did not affect leukocyte counts, we speculate that the underlying therapeutic mechanism is based on differential multi-level modulation of the responses of the different types of leukocytes. Echinaforce(®) thus regulates the production of chemokines and cytokines according to current immune status, such as responsiveness to exogenous stimuli, susceptibility to viral infection and exposure to stress.

Uncoating of human rhinoviruses

Human rhinoviruses (HRVs) are a major cause of the common cold. The more than one hundred serotypes, divided into species HRV-A and HRV-B, either bind intercellular adhesion molecule 1 (major group viruses) or members of the low-density lipoprotein receptor (minor group viruses) for cell entry. Some major group HRVs can also access the host cell via heparan sulphate proteoglycans. The cell attachment protein(s) of the recently discovered phylogenetic clade HRV-C is unknown. The respective receptors direct virus uptake via clathrin-dependent or independent endocytosis or via macropinocytosis. Triggered by ICAM-1 and/or the low pH environment in endosomes the virions undergo conformational alterations giving rise to hydrophobic subviral particles. These are handed over from the receptors to the endosomal membrane. According to the current view, the RNA genome is released through an opening at one of the fivefold axes of the icosahedral capsid and crosses the membrane through a pore presumably formed by viral proteins. Alternatively, the membrane may be ruptured allowing subviral particles and RNA to enter the cytosol. Whether a channel is formed or the membrane is disrupted most probably depends on the respective HRV receptor.

Antiviral therapy for respiratory tract infections

Viruses are important pathogens causing respiratory tract infections both in the community and health‐care facility settings. They are extremely common causes of morbidity in the competent hosts and some are associated with significant mortality in the compromised individuals. With wider application of molecular techniques, novel viruses are being described and old viruses are found to have new significance in different epidemiological and clinical settings. Some of these emerging pathogens may have the potential to cause pandemics or global spread of a severe disease, as exemplified by severe acute respiratory syndrome and avian influenza. Antiviral therapy of viral respiratory infections is often unnecessary in the competent hosts because most of them are self‐limiting and effective agents are not always available. In the immunocompromised individuals or for infections caused by highly pathogenic viruses, such as avian influenza viruses (AIV), antiviral treatment is highly desirable, despite the fact that many of the agents may not have undergone stringent clinical trials. In immunocompetent hosts, antiviral therapy can be stopped early because adaptive immune response can usually be mounted within 5–14 days. However, the duration of antiviral therapy in immunosuppressed hosts depends on clinical and radiological resolution, the degree and duration of immunosuppression, and therefore maintenance therapy is sometimes needed after the initial response. Immunotherapy and immunoprophylaxis appear to be promising directions for future research. Appropriate and targeted immunomodulation may play an important adjunctive role in some of these infections by limiting the extent of end‐organ damage and multi‐organ failure in some fulminant infections.

Host immune responses to rhinovirus: mechanisms in asthma

Viral respiratory infections can have a profound effect on many aspects of asthma including its inception, exacerbations, and, possibly, severity. Of the many viral respiratory infections that influence asthma, the common cold virus, rhinovirus, has emerged as the most frequent illness associated with exacerbations and other aspects of asthma. The mechanisms by which rhinovirus influences asthma are not fully established, but current evidence indicates that the immune response to this virus is critical in this process. Many airway cell types are involved in the immune response to rhinovirus, but most important are respiratory epithelial cells and possibly macrophages. Infection of epithelial cells generates a variety of proinflammatory mediators to attract inflammatory cells to the airway with a subsequent worsening of underlying disease. Furthermore, there is evidence that the epithelial airway antiviral response to rhinovirus may be defective in asthma. Therefore, understanding the immune response to rhinovirus is a key step in defining mechanisms of asthma, exacerbations, and, perhaps most importantly, improved treatment.

Synthesis and the biological evaluation of 2-benzenesulfonylalkyl-5-substituted-sulfanyl-[1,3,4]-oxadiazoles as potential anti-hepatitis B virus agents

Current treatments for chronic hepatitis B virus (HBV) infection include the use of interferon-alpha and of nucleoside analogs lamivudine, adefovir and entecavir. However, the use of interferon-alpha has many side effects while that of nucleosidic inhibitors can lead to the emergence of resistant viruses. Hence, new drugs for the treatment of HBV infection are still highly desired. Oxadiazoles have been observed to exhibit antiviral activities against RNA viruses. In this study, a facile synthesis of 2-benzenesulfonylalkyl-5-substituted-sulfanyl-[1,3,4]-oxadiazoles is reported. The compounds were then evaluated for their anti-HBV activity. 1-[2-[5-(1-Benzenesulfonyl-propyl)-[1,3,4]oxadiazol-2-yl-sulfanyl]-ethyl]-4-(2-methoxy-phenyl)-piperazine (1i) was able to inhibit the expression of the viral antigens, HBsAg and HBeAg in a concentration-dependent manner with no cytotoxic effects and without any effects on the expression of viral transcripts. Concentration- and time-dependent reductions in virion production were also observed. The inhibition of virion production was comparable to that of lamivudine and EC(50) values of 1.63 and 2.96 microM were obtained for compound 1i and lamivudine, respectively. Thus, in addition to the antiviral effects on RNA viruses, oxadiazoles also have anti-HBV activities.

Role of epithelial nitric oxide in airway viral infection

The airway mucosal epithelium is the first site of virus contact with the host, and the main site of infection and inflammation. Nitric oxide (NO) produced by the airway epithelium is vital to antiviral inflammatory and immune defense in the lung. Multiple mechanisms function coordinately to support high-level basal NO synthesis in healthy airway epithelium and further induction of NO synthesis in the infected airway of normal hosts. Hosts deficient in NO synthesis, such as those patients with cystic fibrosis, have impaired antiviral defense and may benefit from therapies to augment NO levels in the airways.

The role of p38 MAPK in rhinovirus-induced monocyte chemoattractant protein-1 production by monocytic-lineage cells

Viral respiratory infections are a major cause of asthma exacerbations and can contribute to the pathogenesis of asthma. Major group human rhinovirus enters cells by binding to the cell surface molecule ICAM-1 that is present on epithelial and monocytic lineage cells. The focus of the resulting viral infection is in bronchial epithelia. However, previous studies of the cytokine dysregulation that follows rhinovirus infection have implicated monocytic lineage cells in establishing the inflammatory environment even though productive infection is not a result. We have determined that human alveolar macrophages and human peripheral blood monocytes release MCP-1 upon exposure to human rhinovirus 16 (HRV16). Indeed, we have found p38 MAPK activation in human alveolar macrophages within 15 min of exposure to HRV16, and this activation lasts up to 1 h. The targets of p38 MAPK activation include transcriptional activators of the MCP-1 promoter. The transcription factor ATF-2, a p38 MAPK substrate, is phosphorylated 45 min after HRV16 exposure. Furthermore, IkappaBalpha, the inhibitor of the transcription factor NF-kappaB, is degraded. Prevention of HRV16 binding was effective in blocking p38 MAPK activation, ATF-2 phosphorylation, and MCP-1 release. This is the first report of a relationship between HRV16 exposure, MCP-1 release and monocytic-lineage cells suggesting that MCP-1 plays a role in establishing the inflammatory microenvironment initiated in the human airway upon exposure to rhinovirus.

Efficacy of zinc against common cold viruses: an overview

Objective

To review the laboratory and clinical evidence of the medicinal value of zinc for the treatment of the common cold.

Data Sources

Published articles identified through Medline (1980–2003) using the search terms zinc, rhinovirus, and other pertinent subject headings. Additional sources were identified from the bibliographies of the retrieved articles.

Study Selection

By the author.

Data Extraction

By the author.

Data Synthesis

Human rhinoviruses, by attaching to the nasal epithelium via the intracellular adhesion molecule-1 (ICAM-1) receptor, cause most colds. Ionic zinc, based on its electrical charge, also has an affinity for ICAM-1 receptor sites and may exert an antiviral effect by attaching to the ICAM-1 receptors in the rhinovirus structure and nasal epithelial cells. Clinical tests of zinc for treatment of common colds have been inconsistent, primarily because of study design, blinding, and lozenge contents. Early formulations of lozenges also were unpalatable. In three trials with similar study designs, methodologies, and efficacy assessments, zinc effectively and significantly shortened the duration of the common cold when it was administered within 24 hours of the onset of symptoms. Recent reports of trials with zinc gluconate administered as a nasal gel have supported these findings; in addition, they have shown that treatment with zinc nasal gel is effective in reducing the duration and severity of common cold symptoms in patients with established illness.

Conclusion

Clinical trial data support the value of zinc in reducing the duration and severity of symptoms of the common cold when administered within 24 hours of the onset of common cold symptoms. Additional clinical and laboratory evaluations are warranted to further define the role of ionic zinc for the prevention and treatment of the common cold and to elucidate the biochemical mechanisms through which zinc exerts its symptom-relieving effects.

New OTC Drugs and Devices 2003: A Selective Review

OBJECTIVES

To present current information about trends development and marketing of over-the-counter (OTC) medications and dietary supplement products and describe new products, delivery systems, home monitoring devices, and home accessories in these markets that are likely generating questions from or posing potential problems for patients.

DATA SOURCES

Recently published clinical and pharmaceutical industry literature.

STUDY SELECTION

By the authors.

DATA EXTRACTION

By the authors.

DATA SYNTHESIS

Last year witnessed the first effort of the Food and Drug Administration (FDA) to remove a dietary supplement from the U.S. market. Ephedra, because of its imminent danger when used for weight reduction and athletic enhancement, was the target of FDA action. FDA has issued a final rule implementing this ban, which prohibits the sale of dietary supplements containing ephedrine alkaloids (e.g., ephedra). Two newer diet-aid products are being actively promoted with little or no safety and effectiveness data. Thus, pharmacist's vigilance is important along with sensible advice on how to lose weight safely and effectively. Further, two independent organizations have created certification programs for dietary supplements that ensure product purity, active ingredient strength, and compliance with good manufacturing practices. In addition, through recent changes in federal legislation, consumers are now able to obtain reimbursement for their nonprescription purchases through flexible spending accounts. Information is presented in this article about selected products in these OTC, home care, and dietary supplement categories: heartburn (proton pump inhibitors), allergy (second-generation antihistamines), constipation (laxatives), diabetes mellitus (blood glucose monitoring systems), home testing (fertility monitoring), nicotine addiction (smoking cessation products), otic disorders (ear syringes), contraceptives and sexual aids (condoms and lubricants), and dermatology (wart removal).

CONCLUSION

Patients continue to increase their reliance on self-care. To assist them, pharmacists must remain up-to-date on trends and have an understanding of the nuances of consumers' behavior and thinking in relation to OTC products and their use.