Human metapneumovirus infections in Mexico: epidemiological and clinical characteristics.
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The human metapneumovirus (hMPV) is a recently described respiratory RNA virus that mainly affects children. To date there has not been a report that describes the detection of this virus in Mexico. This study was performed to detect hMPV in hospitalized Mexican children with respiratory infections, and describe their epidemiological and clinical characteristics. Nasal wash samples from 558 children younger than 3 years of age with the admission diagnosis of a respiratory tract infection were evaluated. Respiratory viruses were detected in 221 children [respiratory syncytial virus (RSV), 193 (34.6 %); influenza virus, 13 (2.3 %); parainfluenza viruses, 15 (2.7 %)]. Respiratory secretions of 323 children in whom the presence of these viruses was excluded (131 admitted during the 2002-2003 respiratory season and 192 during the 2003-2004 season) were tested for hMPV infection. The hMPV genome was detected in 34 specimens by amplification using real-time RT-PCR. Sequencing of amplicons and phylogenetic analysis indicated the predominance of genotype A hMPV. The months with the highest number of hMPV detections were February and March. During the 2002-2003 season hMPV activity peaked after the RSV season. During the 2003-2004 season hMPV and RSV epidemics occurred simultaneously. The clinical presentation of an hMPV infection was indistinguishable from other respiratory infections. Except for one death, the outcomes of the hMPV infections were good. In this study, among the viruses routinely tested for, hMPV was the second most common agent, after RSV, in children younger than 3 years of age hospitalized with respiratory tract infections. (+info)
Nasal colonization with Streptococcus pneumoniae includes subpopulations of surface and invasive pneumococci.
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We demonstrated that during colonization with Streptococcus pneumoniae the nasal mucosal tissues of mice support two populations of pneumococci. Transparent-phase pneumococci can be readily washed from the outer surface, while a second population composed of primarily opaque-phase pneumococci is released only by homogenization of the nasal tissue. The fact that the opaque phase has previously been associated with invasion and the fact that opaque-phase pneumococci were released by homogenization of previously washed nasal tissue suggest that the opaque-phase pneumococci may have invaded the nasal tissue. Consistent with this hypothesis was our observation that there was inflammation in portions of the nasal mucosa of the colonized mice but not in the mucosa of noncolonized mice, but this observation did not prove the hypothesis. If the opaque-phase pneumococci released from the nasal tissue were from within the tissue and/or if resistance of the opaque-phase subpopulation to antibody, complement, and phagocytes is essential for long-term carriage, it seems likely that the virulence factors of S. pneumoniae that are necessary for killing humans exist to facilitate carriage. Although this speculation is unproven, the observation that there are separate populations of pneumococci during colonization may help guide future attempts to understand the biology of nasal colonization by this pathogen. (+info)
Tumour necrosis factor gene polymorphisms and childhood wheezing.
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Tumour necrosis factor (TNF)-alpha is associated with childhood wheezing. A genetic predisposition to increased TNF-alpha production, influenced by single nucleotide gene polymorphisms, may be important. Frequencies of TNF-alpha-308G/A and lymphotoxin (LT)-alpha+252G/A polymorphisms were compared in 115 asthmatic children, 55 wheezy infants and 156 control school children from the UK. Genotype frequencies for the TNF-alpha-308 and LT-alpha+252 polymorphisms were significantly different from controls. Haplotype analysis showed that TNF-alpha-308G, LT-alpha+252A/TNF-alpha-308A, LT-alpha+252A was associated with a markedly increased risk for both asthma and infant wheezing. The TNF-alpha-308G, LT-alpha+252G/TNF-alpha-308G, LT-alpha+252A combination was protective for asthma and infant wheezing. These findings were confirmed by analysis of Caucasian data. Nasal TNF-alpha levels were measured in the infants during acute wheezing episodes and higher, but nonsignificant levels were produced in those with one or two LT-alpha+252A alleles. Unexpectedly, significantly lower nasal TNF-alpha levels were found in the presence of one or two TNF-alpha-308A alleles. TNF-alpha-308/LT-alpha+252 genotype combinations had a significant influence on nasal TNF-alpha levels. In conclusion, these findings may have implications for future early intervention studies by helping to identify infants at increased risk for wheezing and childhood asthma. (+info)
Psoriasin, one of several new proteins identified in nasal lavage fluid from allergic and non-allergic individuals using 2-dimensional gel electrophoresis and mass spectrometry.
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BACKGROUND: Extravasation and luminal entry of plasma occurs continuously in the nose. This process is markedly facilitated in patients with symptomatic allergic rhinitis, resulting in an increased secretion of proteins. Identification of these proteins is an important step in the understanding of the pathological mechanisms in allergic diseases. DNA microarrays have recently made it possible to compare mRNA profiles of lavage fluids from healthy and diseased patients, whereas information on the protein level is still lacking. METHODS: Nasal lavage fluid was collected from 11 patients with symptomatic allergic rhinitis and 11 healthy volunteers. 2-dimensional gel electrophoresis was used to separate proteins in the lavage fluids. Protein spots were picked from the gels and identified using mass spectrometry and database search. Selected proteins were confirmed with western blot. RESULTS: 61 spots were identified, of which 21 were separate proteins. 6 of these proteins (psoriasin, galectin-3, alpha enolase, intersectin-2, Wnt-2B and hypothetical protein MGC33648) had not previously been described in nasal lavage fluids. The levels of psoriasin were markedly down-regulated in allergic individuals. Prolactin-inducible protein was also found to be down-regulated, whereas different fragments of albumin together with Ig gamma 2 chain c region, transthyretin and splice isoform 1 of Wnt-2B were up-regulated among the allergic patients. CONCLUSION: The identification of proteins in nasal lavage fluid with 2-dimensional gelelectrophoresis in combination with mass spectrometry is a novel tool to profile protein expression in allergic rhinitis and it might prove useful in the hunt for new therapeutic targets or diagnostic markers for allergic diseases. Psoriasin is a potent chemotactic factor and its down-regulation during inflammation might be of importance for the outcome of the disease. (+info)
Induction of protective serum meningococcal bactericidal and diphtheria-neutralizing antibodies and mucosal immunoglobulin A in volunteers by nasal insufflations of the Neisseria meningitidis serogroup C polysaccharide-CRM197 conjugate vaccine mixed with chitosan.
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Thirty-six healthy volunteers received either a single intramuscular injection of Neisseria meningitidis serogroup C polysaccharide (MCP)-CRM197 conjugate vaccine in alum or two nasal insufflations 28 days apart of the same vaccine powder, without alum, mixed with chitosan. Nasal immunization was well tolerated, with fewer symptoms reported than after intramuscular injection. The geometric mean concentrations of MCP-specific immunoglobulin G (IgG) after one nasal immunization were 3.25 microg/ml in naive subjects and 14.4 microg/ml in subjects previously immunized parenterally, compared with 4.30 microg/ml in naive subjects immunized intramuscularly. The geometric mean titer of serum bactericidal antibody (SBA) rose 24-fold after two nasal immunizations in naive subjects and was comparable to parenteral immunization (1,080 versus 1,625). All subjects achieved SBA titers associated with protection after two nasal immunizations: even those with titers of <8 at entry. A single nasal immunization boosted the SBA titer to > or =128 in 96% of previously immunized subjects, and two immunizations achieved this level in 92% of naive subjects. MCP-specific IgG levels were approximately 70% IgG2 and approximately 20% IgG1 after nasal or intramuscular immunization. Increases in CRM197-specific IgG and diphtheria toxin-neutralizing activity were observed after nasal or intramuscular immunization, with balanced IgG1/IgG2 and higher IgG4. Significant MCP-specific secretory IgA was detected in nasal wash only after nasal immunization and predominantly on the immunized side. Simple nasal insufflation of existing MCP-CRM197 conjugate vaccines in chitosan offers an inexpensive but effective needle-free prime and boost against serogroup C N. meningitidis and diphtheria. (+info)
Acute effects of a fungal volatile compound.
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OBJECTIVE: 3-Methylfuran (3-MF) is a common fungal volatile product with active biologic properties, and previous studies have indicated a contribution to airway disease. The aim of the present study was to assess the acute health effects of this compound in humans. DESIGN: Acute effects were assessed via chamber exposure to (1 mg/m3) 3-MF. PARTICIPANTS AND MEASUREMENTS: Twenty-nine volunteers provided symptom reports, ocular electromyograms, measurement of eye tear film break-up time,vital staining of the eye, nasal lavage, acoustic rhinometry, transfer tests, and dynamic spirometry. RESULTS: No subjective ratings were significantly increased during exposure. Blinking frequency and the lavage biomarkers myeloperoxidase and lysozyme were significantly increased, and forced vital capacity was significantly decreased during exposure to 3-MF compared with air control. CONCLUSIONS AND RELEVANCE TO CLINICAL PRACTICE: Acute effects in the eyes, nose, and airways were detected and might be the result of the biologically active properties of 3-MF. Thus, 3-MF may contribute to building-related illness. (+info)
Association of human metapneumovirus with acute otitis media.
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OBJECTIVE: Human metapneumovirus (hMPV) is a recently described paramyxovirus that has been associated with acute upper and lower respiratory infection (LRI) in infants and children worldwide. We previously observed that one-third of the children with hMPV-associated LRI had been diagnosed with a concomitant acute otitis media (AOM). In the current study, we sought to investigate an association between hMPV and children presenting with AOM as a primary diagnosis. METHODS: We used realtime RT-PCR for hMPV to retrospectively test 144 paired nasal wash (NW) and middle ear fluid (MEF) specimens that had been prospectively collected from children with AOM during a 3-year period from 1990-1992. RNA was extracted from archived, frozen samples and realtime RT-PCR for hMPV was performed. RESULTS: We detected hMPV in 8/144 (6%) NW and 1/144 MEF. Several of the children still tested positive for hMPV in NW 3 days later, showing persistent virus shedding. All were detected from November-May and six had bacterial co-pathogens. Two of the eight (25%) hMPV-infected children had no bacterial pathogen isolated, suggesting that hMPV may be associated with AOM as a sole pathogen. CONCLUSIONS: These data show that hMPV is associated with a proportion of AOM and thus has additional morbidity and healthcare impact related to these illnesses. (+info)
Qualitative aspects of nasal irrigation use by patients with chronic sinus disease in a multimethod study.
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PURPOSE: We qualitatively assessed attitudes regarding use of hypertonic saline nasal irrigation (HSNI) for frequent rhinosinusitis and chronic sinonasal symptoms in a 3-part, multimethod study. METHODS: We conducted semistructured, in-depth interviews with 28 participants who recently used nasal irrigation in studies assessing HSNI. RESULTS: Four themes emerged: (1) HSNI improved self-management of sinus symptoms, creating a sense of empowerment; (2) HSNI produced rapid and long-term improvement in quality of life; (3) participants identified discomfort, time, and mild side effects as barriers to HSNI use; and (4) participants identified aspects of training and at-home use that overcame these barriers. CONCLUSION: HSNI is a safe, well-tolerated, inexpensive, effective, long-term therapy that patients with chronic sinonasal symptoms can and will use at home with minimal training and follow-up. Success with HSNI will likely be improved by patient education. (+info)