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Biomedical subjects

Frederick G Hayden

Publications and source records attributed to Frederick G Hayden.

53 records · Page 3Linked to original sources
PubMed2003

Experimental rhinovirus challenges in adults with mild asthma: response to infection in relation to IgE.

BACKGROUND: Although most children and young adults with asthma are atopic, exacerbations of asthma are frequently associated with viral respiratory tract infections, especially those caused by rhinovirus (HRV). OBJECTIVE: Young atopic adults with mild asthma were evaluated before and during an experimental HRV infection to test the hypothesis that airway inflammation before virus inoculation may be a risk factor for an adverse response to HRV. METHODS: Experimental HRV infections were evaluated in 16 allergic volunteers with mild asthma and 9 nonatopic control patients (age, 18 to 30 years). Before virus inoculation, each participant was screened with tests for lung function, prick skin tests for sensitization to common aeroallergens, measurements of total serum IgE, and serum neutralizing antibody to rhinovirus-16 (the serotype used for inoculation). The response to infection was monitored for 21 days by using symptom diary cards, tests for lung function, and markers of airway inflammation in nasal washes, blood, and expired air. RESULTS: During the infection, asthmatic patients had cumulative upper and lower respiratory tract symptom scores that were significantly greater over the course of 21 days than scores from the control patients. At baseline, the asthmatic patients also had increased sensitivity to methacholine and significantly lower values for FEV(1) (percent predicted) than the control patients (geometric mean and intraquartile values: 87% [79% to 91%] for the asthmatic patients and 101% [90% to 104%] for the control patients, P <.03). Among the patients with mild asthma, 6 had levels of total serum IgE that were substantially elevated (range, 371 to 820 IU/mL) compared with 10 who had lower levels (range, 29 to 124 IU/mL). Those with high levels of IgE had significantly greater lower respiratory tract symptom scores during the initial 4 days of the infection than the low IgE group. They also had higher total blood eosinophil counts at baseline, increased eosinophil cationic protein in their nasal washes (>200 ng/mL), and augmented levels of expired nitric oxide at baseline and during peak cold symptoms. In contrast, levels of soluble intracellular adhesion molecule-1 in nasal wash supernatants from the asthmatic patients with high IgE were diminished, both at baseline and during the infection. CONCLUSIONS: The reduced lung function and increased markers of inflammation observed before virus inoculation in the asthmatic patients who had high levels of total serum IgE may be risk factors for an adverse response to infections with HRV.

Adolescent↗
PubMed2003

Phase II, randomized, double-blind, placebo-controlled studies of ruprintrivir nasal spray 2-percent suspension for prevention and treatment of experimentally induced rhinovirus colds in healthy volunteers.

Human rhinovirus (HRV) infections are usually self-limited but may be associated with serious consequences, particularly in those with asthma and chronic respiratory disease. Effective antiviral agents are needed for preventing and treating HRV illnesses. Ruprintrivir (Agouron Pharmaceuticals, Inc., San Diego, Calif.) selectively inhibits HRV 3C protease and shows potent, broad-spectrum anti-HRV activity in vitro. We conducted three double-blind, placebo-controlled clinical trials in 202 healthy volunteers to assess the activity of ruprintrivir in experimental HRV infection. Subjects were randomized to receive intranasal ruprintrivir (8 mg) or placebo sprays as prophylaxis (two or five times daily [2x/day or 5x/day] for 5 days) starting 6 h before infection or as treatment (5x/day for 4 days) starting 24 h after infection. Ruprintrivir prophylaxis reduced the proportion of subjects with positive viral cultures (for 5x/day dosing groups, 44% for ruprintrivir treatment group versus 70% for placebo treatment group [P=0.03]; for 2x/day dosing groups, 60% for ruprintrivir group versus 92% for placebo group [P=0.004]) and viral titers but did not decrease the frequency of colds. Ruprintrivir treatment reduced the mean total daily symptom score (2.2 for ruprintrivir treatment group and 3.3 for the placebo treatment group [P=0.014]) by 33%. Secondary endpoints, including viral titers, individual symptom scores, and nasal discharge weights, were also reduced by ruprintrivir treatment. Overall, ruprintrivir was well tolerated; blood-tinged mucus and nasal passage irritation were the most common adverse effects reported. Pharmacokinetic analysis of plasma and nasal ruprintrivir concentrations revealed intranasal drug residence with minimal systemic absorption. Results from these studies in experimental rhinoviral infection support continued investigation of intranasal ruprintrivir in the setting of natural HRV infection.

Administration, Inhalation↗
PubMed2003

Safety and efficacy of nebulized zanamivir in hospitalized patients with serious influenza.

Influenza is an important cause of hospitalization due to lower respiratory tract involvement for which there is no specific antiviral treatment with proven efficacy. We conducted a double-blind, randomized, placebo-controlled trial to assess the tolerability and efficacy of nebulized zanamivir (16 mg four times a day) in combination with rimantadine compared to rimantadine with nebulized saline for treating influenza in adults hospitalized with influenza. Twenty patients tolerated the inhaled zanamivir (ZNV) plus rimantadine without decline in peak expiratory flow rates compared to the 21 who received inhaled saline. The study was terminated early because the approval of ZNV made further enrollment untenable. No significant differences were observed in the proportion of patients shedding virus by treatment day 3 (57% ZNV plus rimantadine, 67% placebo plus rimantadine), or in the durations of hospitalization and supplemental oxygen use. More ZNV plus rimantadine recipients exhibited no or mild cough on day 3 of treatment (94 vs 55%, P=0.01). Two rimantadine-resistant viruses emerged during rimantadine monotherapy; no ZNV resistance was observed. Nebulized ZNV appears to be well tolerated in this hospitalized population but further studies are needed to assess its efficacy.

Adult↗
PubMed2002

Assessment of hemagglutinin sequence heterogeneity during influenza virus transmission in families.

To examine the molecular epidemiology of influenza virus transmission, the nucleotide sequences of the HA1 domain of the hemagglutinin (HA) gene of 57 influenza A and 24 influenza B viruses recovered in a single season were analyzed. No nucleotide sequence differences were found among the 10 viruses that were recovered twice from the same patient. The nucleotide sequences of influenza A viruses were identical within each family but varied among the 14 families included in the study. The sequences of influenza A viruses recovered from 18 residents of the same community showed that 83% of the viruses differed from the others by at least 1 nucleotide residue. These findings indicate that most cases of influenza in households in which 1 family member has been infected are the result of secondary transmission from the index patient and not of acquisition from other community sources. Substantial genetic conservation during virus transmission within households is indicated.

Adolescent↗
PubMed2002

Rhinovirus and coronavirus infection-associated hospitalizations among older adults.

Rhinoviruses and coronaviruses are recognized as the major causes of the common cold syndrome. The role of these viruses in more serious respiratory illnesses resulting in hospitalization is less well defined. During a winter when influenza A infection was prevalent, 100 elderly adults hospitalized because of cardiopulmonary illnesses were evaluated for rhinovirus and coronavirus infection. Patients who tested negative for influenza or respiratory syncytial virus had nasal swab samples tested for rhinovirus, coronavirus OC43, and coronavirus 229E by reverse-transcription polymerase chain reaction and for coronaviruses by serologic testing. Twelve percent of patients had rhinovirus or coronavirus identified (rhinovirus, 4 patients; coronavirus 229E, 4 patients; coronavirus OC43, 3 patients; and mixed rhinovirus/coronavirus 229E infection, 1 patient). All patients had significant underlying diseases. Although all patients recovered, the mean length of stay was 8 days; 4 persons had pneumonia, and 1 required ventilator support. These data suggest that rhinoviruses and coronaviruses may be associated with serious respiratory illnesses in frail older adults.

Aged↗
PubMed2002

Accumulation of defective neuraminidase (NA) genes by influenza A viruses in the presence of NA inhibitors as a marker of reduced dependence on NA.

With the use of neuraminidase (NA) inhibitors (BCX-1812, oseltamivir, or zanamivir), drug-resistant variants of influenza A viruses were generated that lacked characteristic markers of resistance, such as substitutions in the NA active center or in the hemagglutinin. Drug resistance was associated with the accumulation of defective (Delta) RNA segments encoding NA. This phenomenon could be explained by reduced dependence of the virus on its NA activity. Analysis of the last isolates recovered from 11 volunteers, experimentally infected with influenza virus and treated with BCX-1812, revealed that they maintained full susceptibility to the drug in the NA inhibition assay (50% inhibitory concentration, 0.35-0.5 nM). The presence of DeltaRNA segments was detected in 1 of these isolates but was not found in the isolates recovered from placebo recipients (n = 8). Because of a lack of cell culture-based assays for susceptibility testing of human influenza viruses, detection of DeltaRNA segments should be considered an additional assay for monitoring of NA inhibitor resistance.

Acetamides↗
PubMed2002

Expression of ICAM-1 in nasal epithelium and levels of soluble ICAM-1 in nasal lavage fluid during human experimental rhinovirus infection.

Most rhinovirus serotypes use intercellular adhesion molecule-1 (ICAM-1) as the receptor to enter cells, but ICAM-1 expression has not been detected on normal nasal epithelial cells. During experimental rhinovirus infection, expression of ICAM-1 on nasal epithelial cells was examined with immunohistochemical staining of nasal scrape biopsy specimens, and levels of soluble ICAM-1 in nasal lavage fluid were measured by sandwich enzyme-linked immunosorbent assay technique. Expression of ICAM-1 on nasal epithelial cells increased following inoculation in 20 of 23 infected subjects. The median number of ICAM-1-positive cells per 6.25-mm(2) area of stained biopsy specimen was 0 in control samples (day 20 or 33 after inoculation), and in those without infection, 6 on day 1 (P< or =.05), 14.5 on day 3 (P< or =.01), 1.5 on day 5, and 0 on day 9. In a different group of volunteers, soluble ICAM-1 in nasal lavage fluid was higher on days 1 and 3 compared with preinoculation levels (P< or =.001), but only 11 of 23 infected subjects had a 2-fold or greater increase. Up-regulation of ICAM-1 receptor expression on nasal epithelial cells occurred within 24 hours after inoculation in experimental rhinovirus infections (prior to onset of symptoms) and declined promptly by day 5.

Adult↗
PubMed2002

Detection of influenza virus resistance to neuraminidase inhibitors by an enzyme inhibition assay.

We previously characterized influenza viruses whose selection in the presence of neuraminidase (NA) inhibitors resulted in a substituted residue (position 119,152,274, or 292) in the NA active center. To identify the most favorable conditions for detecting NA inhibitor-resistant viruses we compared the results of four modifications of the NA inhibition assay utilizing a fluorogenic substrate. The IC50 values were highly dependent upon assay conditions, and most mutant enzymes were more sensitive to changes in assay conditions (e.g. addition of PO4(3-), Ca2+, DMSO, or EDTA) than wild-type enzymes or a mutant NA with an Arg292-->Lys substitution. Although the levels of resistance to zanamivir, oseltamivir carboxylate, and BCX-1812 (RWJ-270201) for each mutant varied among assays, mutants with substitutions at framework residues 119 or 274 exhibited sensitivity to at least one inhibitor. Viruses with substitutions at catalytic residues 152 or 292 were resistant to each inhibitor in all assays. Monitoring resistance in a clinical setting will require a panel of resistant viruses to ensure that assay conditions are favorable for detecting variants with substituted residues in the NA active center. Because variants selected in the presence of one NA inhibitor could be variably resistant to other inhibitors, all three inhibitors should be used in drug susceptibility testing.

Acetamides↗
PubMed2002

Influenza in the acute hospital setting.

Influenza poses special hazards inside healthcare facilities and can cause explosive outbreaks of illness. Healthcare workers are at risk of acquiring influenza and thus serve as an important reservoir for patients under their care. Annual influenza immunisation of high-risk persons and their contacts, including healthcare workers, is the primary means of preventing nosocomial influenza. Despite influenza vaccine effectiveness, it is substantially underused by healthcare providers. Influenza can be diagnosed by culturing the virus from respiratory secretions and by rapid antigen detection kits; recognition of a nosocomial outbreak is important in order to employ infection-control efforts. Optimal control of influenza in the acute-care setting should focus upon reducing potential influenza reservoirs in the hospital, including: isolating patients with suspected or documented influenza, sending home healthcare providers or staff who exhibit typical symptoms of influenza, and discouraging persons with febrile respiratory illness from visiting the hospital during a known influenza outbreak in the community. (Note: influenza and other respiratory viruses can cause non-febrile illness but are still transmissible.) The antiviral M2 protein inhibitors (amantadine, rimantadine) and neuraminidase inhibitors (zanamivir, oseltamivir) have proven efficacy in treating and preventing influenza illness; however, their role in the prevention and control of influenza in the acute hospital setting remains to be more fully studied.

Acetamides↗
PubMed2002

Viral infections in immunocompromised patients: what's new with respiratory viruses?

PURPOSE OF REVIEW: The leading cause of death in solid organ and hematopoietic stem cell transplant recipients is infection. The respiratory viruses, particularly respiratory syncytial virus, influenza, parainfluenza, adenovirus, and picornaviruses, are increasingly recognized as significant pathogens in these populations. RECENT FINDINGS: Respiratory syncytial virus has again been found to be the most common of the respiratory viruses causing severe infections in transplant recipients. Advances in prevention, particularly with regard to infection control practices, and to lesser extent treatment have had a substantial impact on the frequency and outcomes of this infection. New studies have clarified the impact of influenza in the hematopoietic stem cell transplant recipients and have provided evidence to support the use of M2 and neuraminidase inhibitors for early treatment. The epidemiology of parainfluenza and adenovirus in transplant recipients has been clarified, although therapeutic modalities are still limited and understudied. New antiviral medications may bring improved outcomes of picornavirus infections in this population. Finally, a new virus, the human metapneumovirus, has recently been described and may be a significant respiratory pathogen in immunocompromised transplant recipients. SUMMARY: Studies published over the past year have documented a new respiratory pathogen. They have also resulted in improved understanding of the epidemiology of all of the respiratory virus pathogens, and have contributed to improve management of respiratory syncytial virus and influenza infection in hematopoietic stem cell transplant and solid organ transplant recipients.

Antiviral Agents↗
PubMed2002

A release-competent influenza A virus mutant lacking the coding capacity for the neuraminidase active site.

Both influenza A virus surface glycoproteins, the haemagglutinin (HA) and neuraminidase (NA), interact with neuraminic acid-containing receptors. The influenza virus A/Charlottesville/31/95 (H1N1) has shown a substantially reduced sensitivity to NA inhibitor compared with the A/WSN/33 (H1N1) isolate by plaque-reduction assays in Madin-Darby canine kidney (MDCK) cells. However, there was no difference in drug sensitivity in an NA inhibition assay. The replacement of the HA gene of A/WSN/33 with the HA gene of A/Charlottesville/31/95 led to a drastic reduction in sensitivity of A/WSN/33 to NA inhibitor in MDCK cells. Passage of A/Charlottesville/31/95 in cell culture in the presence of an NA inhibitor resulted in the emergence of mutant viruses (delNA) whose genomes lacked the coding capacity for the NA active site. The delNA mutants were plaque-to-plaque purified and further characterized. The delNA-31 mutant produced appreciable yields ( approximately 10(6) p.f.u./ml) in MDCK cell culture supernatants in the absence of viral or bacterial NA activity. Sequence analysis of the delNA mutant genome revealed no compensatory substitutions in the HA or other genes compared with the wild-type. Our data indicate that sialylation of the oligosaccharide chains in the vicinity of the HA receptor-binding site of A/Charlottesville/31/95 virus reduces the HA binding efficiency and thus serves as a compensatory mechanism for the loss of NA activity. Hyperglycosylation of HA is common in influenza A viruses circulating in humans and has the potential to reduce virus sensitivity to NA inhibitors.

Acids, Carbocyclic↗
PubMed2002

Viral respiratory infection in schoolchildren: effects on middle ear pressure.

OBJECTIVE: To evaluate the effect of uncomplicated viral respiratory infections (colds) on middle ear pressure in healthy school-aged children. METHODS: Children (ages 2-12) with normal tympanograms before onset of illness had bilateral tympanometry daily except weekends for 2 weeks after the onset of a cold. Nasopharyngeal secretion obtained at onset of illness was cultured for bacterial pathogens of otitis media using selective agars and tested for rhinovirus, coronavirus, respiratory syncytial virus, influenza A and B, and parainfluenza 1-3 by reverse transcriptase polymerase chain reaction technology. Tympanometry was designated as abnormal with peak pressure of < or =-100 daPa or > or =50 daPa and/or a compliance peak of < 0.2 cm(3). RESULTS: Eighty-six colds were studied, 82 in schoolchildren (5-12 years old) and 4 in 2- to 3-year-olds. Abnormal negative middle ear pressure occurred at least once during the 2 weeks after onset in 57 (66%) of the 86 colds. Tympanometry was abnormal in the first week after onset in 50 (88%) of the 57 colds and was abnormal on a single day in 17 (30%) of the 57. The middle ear pressure abnormalities were intermittent and shifted from one ear to the other ear from day to day. Reverse transcriptase polymerase chain reaction was positive for a respiratory virus in 56 (65%) of the 86 illnesses. Rhinovirus was found in 48% and respiratory syncytial virus in 14%. Pathogenic bacteria (Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis) were detected in nasopharyngeal secretion in 29 (34%) of the 86 colds; the bacteria were in high titer (> or =10(3) cfu/mL) in 26 of the 29 positive specimens. None developed illness that required a visit to a physician. Age, detection of a respiratory virus, and presence of bacterial pathogen in the nasopharyngeal secretion had a negligible effect on the occurrence of abnormal tympanometry. Occurrence of negative middle ear pressure in winter-spring colds was significantly greater than in fall colds for unexplained reasons. CONCLUSIONS: Transient negative middle ear pressure occurred in two thirds of uncomplicated colds in healthy children. This negative pressure, which may facilitate secondary viral or bacterial otitis media, seems to result from viral infection of the nasopharynx and distal tube causing bilateral eustachian tube dysfunction. Tympanometry provides an objective measure of the potential beneficial effects of investigational treatments on the risk of eustachian tube dysfunction/otitis media.

Acoustic Impedance Tests↗
PubMed2002

Oral pleconaril treatment of picornavirus-associated viral respiratory illness in adults: efficacy and tolerability in phase II clinical trials.

We evaluated the efficacy and tolerability of oral pleconaril, an anti-picornavirus agent, in treating acute viral respiratory illness (VRI) in two double-blind, placebo-controlled trials. Otherwise healthy subjects, 14 years of age or older, who presented within 36 h of VRI symptom onset, were randomized to pleconaril 400 mg or matching placebo in liquid (first trial) or tablet (second trial) formulations twice-daily (first trial only) or three-times daily for 7 days. The infected subjects from the corresponding active and placebo groups (three-times daily dosing regimens) were combined for analysis. Among the subset of subjects with proven picornaviral infection in both studies (42% of total enrolled), pleconaril 400 mg three-times daily (n = 323) reduced the time to alleviation of illness (no rhinorrhoea and other symptoms mild or absent for > or = 48 h) compared with placebo (n = 264) (median: 10.0 days for placebo and 8.5 days for pleconaril; P = 0.029). In addition, pleconaril reduced the time to a > or = 50% reduction from baseline in total symptom severity score (median: 4.5 days for placebo and 3.5 days for pleconaril; P = 0.038). Significant reductions in the number of tissues used for nose-blowing (20% reduction) and in nights of disturbed sleep (16% reduction) were also observed. Pleconaril was generally well tolerated; the liquid formulation caused gastrointestinal disturbance in all groups (diarrhoea 10-14%, nausea 5-9%, abdominal discomfort 6-8%), and tablets were associated with a greater incidence of nausea (3% for placebo versus 7% for pleconaril, P = 0.003). Pleconaril 400 mg administered three-times daily reduced the duration and severity of picornaviral VRI in adolescents and adults.

Administration, Oral↗
PubMedDate not supplied

Rhinovirus and the lower respiratory tract.

Human rhinoviruses (HRVs) are well-recognised causes of common colds and associated upper respiratory tract complications such as sinusitis and otitis media. This article reviews information linking HRV infection to illness in the lower respiratory tract. HRVs are capable of efficient replication in vitro at temperatures present in the tracheobronchial tree and have been shown to cause productive infection, elaboration of cytokines and chemokines, and up-regulation of cell surface markers in human bronchial epithelial cells. In situ hybridisation studies have proven that HRV infection occurs in the tracheobronchial tree following experimental infection. Clinical studies report that HRV infection is the second most frequently recognised agent associated with pneumonia and bronchiolitis in infants and young children and commonly causes exacerbations of pre-existing airways disease in those with asthma, chronic obstructive pulmonary disease or cystic fibrosis. HRV infection is associated with one-third to one-half of asthma exacerbations depending on age and is linked to asthma hospitalisations in both adults and children. Limited information implicates HRV infection as a cause of severe lower respiratory tract illness in older adults and in highly immunocompromised hosts, particularly bone marrow transplant recipients. More information is needed about the pathogenesis of HRV infection with regard to lower respiratory tract complications in these diverse patient groups. Given the large unmet medical need associated with HRV infections, safe and effective antiviral agents are needed for both prevention and treatment of these infections.

Adolescent↗
PubMedDate not supplied

Resistant influenza A viruses in children treated with oseltamivir: descriptive study.

BACKGROUND: Oseltamivir is an effective inhibitor of influenza virus neuraminidase. Although viruses resistant to oseltamivir emerge less frequently than those resistant to amantadine or rimantadine, information on oseltamivir-resistant viruses arising during clinical use of the drug in children is limited. Our aim was to investigate oseltamivir resistance in a group of children treated for influenza. METHODS: We analysed influenza A viruses (H3N2) collected from 50 children before and during treatment with oseltamivir. We sequenced the genes for neuraminidase and haemagglutinin and studied the mutant neuraminidases for their sensitivity to oseltamivir carboxylate. FINDINGS: We found neuraminidase mutations in viruses from nine patients (18%), six of whom had mutations at position 292 (Arg292Lys) and two at position 119 (Glu119Val), which are known to confer resistance to neuraminidase inhibitors. We also identified another mutation (Asn294Ser) in one patient. Sensitivity testing to oseltamivir carboxylate revealed that the neuraminidases of viruses that have an Arg292Lys, Glu119Val, or Asn294Ser mutation were about 10(4)-10(5)-fold, 500-fold, or 300-fold more resistant than their pretreatment neuraminidases, respectively. Oseltamivir-resistant viruses were first detected at day 4 of treatment and on each successive day of the study. More than 10(3) infectious units per mL of virus were detected in some of the patients who did not shed drug-resistant viruses, even after 5 days of treatment. INTERPRETATION: Oseltamivir-resistant mutants in children being treated for influenza with oseltamivir arise more frequently than previously reported. Furthermore, children can be a source of viral transmission, even after 5 days of treatment with oseltamivir.

Acetamides↗
PubMedDate not supplied

Nasopharyngeal reservoir of bacterial otitis media and sinusitis pathogens in adults during wellness and viral respiratory illness.

BACKGROUND: The carriage rate of pathogenic bacteria in the nasopharynx (NP) was determined using three separate techniques for obtaining samples. METHODS: The NP of 99 healthy adults was sampled with (1) nasal swab, (2) oral swab, and (3) nasal aspiration; 49 adults with common cold were sampled with an oral swab and nasal aspiration. Three selective agars were used to detect Streptococcus pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis. RESULTS: Seventy-three percent of healthy adults and 74% of cold sufferers had at least one pathogen detected in the NP. Detection rates were 65% (oral NP swab), 38% (catheter aspiration), and 28% (nasal swab; p < 0.001). Carriage rates for S. pneumoniae, M. catarrhalis, and H. influenzae were 45, 33, and 30%, respectively. Both a nasal and an oral sample were required for optimal detection. CONCLUSION: Bacterial pathogens were present in the NP of three-quarters of adults during wellness and during colds.

Adult↗