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At least 37 records · Page 2Linked to original sources
PubMed2002

Respiratory syncytial virus infection suppresses lung CD8+ T-cell effector activity and peripheral CD8+ T-cell memory in the respiratory tract.

Respiratory syncytial virus (RSV) is a major cause of morbidity from respiratory infection in infants, young children and the elderly. No effective vaccine against RSV is currently available and studies of the natural history of RSV infection suggest repeated infections with antigenically related virus strains are common throughout an individual's lifetime. We have studied the CD8+ T-cell response during experimental murine RSV infection and found that RSV inhibits the expression of effector activity by activated RSV-specific CD8+ T cells infiltrating the lung parenchyma and the development of pulmonary CD8+ T-cell memory by interfering with TCR-mediated signaling. These data suggest a possible mechanism to explain the limited duration of protective immunity in RSV infection.

Animals↗
PubMedDate not supplied

[Effect of environmental factors on the defense system of the respiratory tract].

Respiratory system due to its enormous surface is particularly prone to be penetrated by various exogenous factors. Therefore, this system is equipped with numerous local, specific and unspecific, cellular and humoral immunological mechanisms. This system includes: BALT (bronchial ++adeno-lymphatic tissue) producing secretory immunoglobulins, ciliary system, mucus which provides an extracellular surface for immunoglobulins, lysozyne, interferon, lactoferrin, and complement system activities. Moreover, alveolar macrophages, surfactant, neuropeptides, and inflammatory processes constitute other components of the whole defense system. A complex interactions increasing its efficiency take place between particular components. Unfavourable environmental factors attack this system in several ways. The most important are: recurrent bacterial and viral respiratory infections, air pollution, tobacco smoke, and unfavourable climate and microclimate.

Environmental Exposure↗
PubMed1987

[Microflora of the upper respiratory tract of normal young children and in respiratory tract diseases. Normal microflora and dysbiosis at different levels of the upper respiratory tract in healthy children and pneumonia patients].

Material obtained from the mucous membranes of the upper respiratory tract (the anterior section of the nasal cavity, the fauces) in young children, both healthy and suffering with different forms of acute pneumonia, has been analyzed with due regard to the structure of the microflora, its specific composition and the size of populations formed by different species constituting the microflora. This analysis has made it possible to determine the species constituting normal microflora, to detect its dysbiotic changes, and to determine their degree (partial or complete dysbacteriosis). The degree of pathologic changes in the microecological balance of the upper respiratory tract has been shown to reflect the severity of acute pneumonia and to be determined by the characteristics of the natural resistance system in young children.

Bacteria↗
PubMed1991

The influence of upper respiratory tract surgery on respiratory function evaluated by oxygen saturation.

To evaluate the influence of upper respiratory tract surgery on respiratory function, we used a pulse oximeter to measure the arterial oxygen saturation in 40 patients (ASA 1 or 2) during surgery under local anesthesia. The patients were divided into four groups: a control group of 10 patients who underwent surgery not involving the upper respiratory tract, and three upper respiratory tract surgery groups of 10 patients each underwent surgery on the nasal cavity alone (group 1), on the oral cavity alone (group 2), and on both the oral and nasal cavities (group 3). Groups 1 and 2 showed little desaturation compared to their baseline levels and the control group, while group 3 showed a mild desaturation even at the beginning of surgery and this gradually turned to a moderate or severe desaturation. This was due to both the extension of the surgical zone to the nasal and oral cavities and to ventilatory distress produced by massive bleeding and aspiration of secretions. Thus, the pulse oximeter is a useful monitor for upper respiratory tract surgery involving both general and local anesthesia. It allows the identification of hypoxia so that remedial therapy can be instituted.

Journal Article↗
PubMed1999

Susceptibility of Streptococcus pneumoniae isolated from the respiratory tract of hospitalized children with respiratory tract infections.

The most frequent nasopharyngeal carriers of Streptococcus pneumoniae are young children. Frequent use of antimicrobial therapy in children facilitates the selection of penicillin-resistant strains in this population. These strains, especially if highly resistant, may cause serious therapeutic problems. Aim of the study was to monitor penicillin- and multidrug-resistant S. pneumoniae strains in hospitalized children with respiratory tract infections. Hospitalized children up to five years were examined for S. pneumoniae presence in their upper respiratory tract. Susceptibility to penicillin, erythromycin, trimethoprim/sulfamethoxazole, tetracycline, and chloramphenicol was determined by the disk-diffusion method. The minimal inhibitory concentrations (MIC) of penicillin, erythromycin and trimethoprim/sulfamethoxazole were measured by the E-test. S. pneumoniae strain was isolated from 60 (34.7%) out of 173 microbiologically examined children; 2 different strains were isolated in 9 cases. Nine strains (13.0%) were penicillin resistant with MICs ranging from 1.5 to 8 mg/L, and 17 strains (24.6%) had intermediate susceptibility. Seventeen (24.6%) strains were erythromycin resistant (MIC > or = 1 mg/L). Eighteen strains (26.1%) were resistant and 7 strains (10.1%) were intermediately susceptible to trimethoprim/sulfamethoxazole. Ten strains (14.5%) were not susceptible to tetracycline, and 11 (15.9%) to chloramphenicol. Non-susceptibility (resistance or intermediate susceptibility) to the tested antimicrobials was more prevalent in penicillin-nonsusceptible strains. The current level of S. pneumoniae resistant to antimicrobial drugs in children with respiratory tract infections in the hospital department monitored in our study do not cause problems in the choice of antibacterial therapy. Penicillins still can remain the drug of choice in cases when typical bacterial causing agents of respiratory tract infections are suspected. (Tab. 3, Fig. 2, Ref. 31.)

Child, Preschool↗
PubMed2006

Study of upper respiratory tract bacterial flora: first report. Variations in upper respiratory tract bacterial flora in patients with acute upper respiratory tract infection and healthy subjects and variations by subject age.

With the appearance of penicillin-resistant Streptococcus pneumoniae, there has been increasing debate concerning antimicrobial treatments for acute upper respiratory tract infection (AURTI) and acute otitis media in children. This study compares the nasopharyngeal bacterial flora in patients with AURTI (AURTI group; 710 subjects) and healthy subjects (HS group; 380 subjects). The comparisons were made between subjects aged 6 years or younger (0-6 subgroup: 330 subjects), between 7 and 74 years (7-74 subgroup: 668 subjects), and 75 years and older (92 subjects), because the subjects were subgrouped as described above dependent on the maturity of the protective immunity. In the HS group 7-74 subgroup, viridans group streptococci, Staphylococcus aureus, coagulase-negative staphylococci, and Corynebacterium sp. with a detection rate of 10% or more were classified as normal nasal flora (NNF), and Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis were classified as drum cavity pathogens (DCP). In the 0-6 subgroup, although the detection rate for DCP bacteria in the AURTI group tended to be high, it did not reach a significant difference, whereas the detection rate for NNF bacteria was significantly lower. This trend was also observed to some degree in the other age subgroup. In the 0-6 subgroup, leukocyte infiltration observed with a microscope indicated the closest relationship between S. pneumoniae detection rate and detection quantity. These results suggest that in the 0-6 subgroup the tendency for patients with AURTI to have NNF bacteria as well as DCP bacteria should be taken into consideration.

Acute Disease↗
PubMed1986

[Microflora of the upper respiratory tract in young children under normal conditions and in respiratory tract diseases. Microbial count of the upper respiratory tract in healthy children and in children with pneumonia].

The results of the inoculation of material taken from the anterior section of the nasal cavity and from the pharyngeal mucosa of 50 healthy young children and 298 acute pneumonia patients were analyzed. 23 microbial species were isolated. In the samples taken from the anterior section of the nasal cavity, monocultures were detected in 86 samples and 54 variants of associations including 2-4 species, in 139 samples. In the samples taken from the pharynx, monocultures were detected in 59 samples and 180 variants of associations including 2-6 species, in 282 samples. Differences in the contamination of the nasal cavity and the pharynx in healthy children and in pneumonia patients were revealed. These differences were manifested in the structure of the microflora (monocultures, associations, their composition), the assortment of microbial species and their concentration. In young children with pneumonia the microflora of the upper respiratory tract was found to reflect the severity of acute pneumonia and the intensity of the pathological process in the lungs (uncomplicated, pyodestructive pneumonia, pyodestructive pneumonia with fatal termination, acute purulent pleurisy).

Acute Disease↗
PubMed2005

Prospective study of the incidence, clinical features, and outcome of symptomatic upper and lower respiratory tract infections by respiratory viruses in adult recipients of hematopoietic stem cell transplants for hematologic malignancies.

Respiratory viruses (RVs) are known to be major causes of morbidity and mortality in recipients of hematopoietic stem cell transplants (HSCTs), but prospective long-term studies are lacking. We prospectively screened all adult HSCT recipients (172 allogeneic [alloHSCT] and 240 autologous [autoHSCT]) who underwent transplantation during a 4-year period (1999 to 2003) for the development of a first episode of symptomatic upper respiratory tract infections and/or lower respiratory tract infections (LRTI) by an RV. RVs studied were influenza A and B viruses (n=39), human respiratory syncytial virus (n=19), human adenoviruses (n=11), human parainfluenza viruses 1 to 3 (n=8), human enteroviruses (n=5), human rhinoviruses (n=3), and the recently discovered human metapneumoviruses (n=19). During the study, 51 and 32 cases of RV symptomatic infections were identified of alloHSCT and autoHSCT recipients (2-year incidence, 29% and 14%, respectively). Risk factors for progression of upper respiratory tract infection to LRTI included severe (<0.2x10(9)/L) and moderate (<0.2x10(9)/L) lymphocytopenia in alloHSCT (P=.02) and autoHSCT (P=.03). Death from LRTI was attributed to an RV in 8 alloHSCT recipients. Symptomatic RV had no effect on 2-year outcomes, with the possible exception of influenza A and B virus infections in autoHSCT: these were associated with nonrelapse mortality (P=.02). In conclusion, this prospective trial allows an estimation of the minimum incidence of a first RV infection in adult HSCT recipients and identifies risk factors for acquisition of an RV infection and progression to LRTI; this should aid in the design of future studies. In addition, human metapneumovirus should be added to the potentially serious causes of RV infections in HSCT.

Adult↗
PubMed1984

[Pharmacological effects of brovanexine hydrochloride (BR-222) on the respiratory tract system, particularly on the respiratory tract fluid, mucociliary transport and cough].

Pharmacological effects of brovanexine hydrochloride (BR-222), a new expectorant, on the respiratory tract system was studied in comparison with that of bromhexine hydrochloride. 1. When doses ranging from 5 to 40 mg/kg of BR-222 were given orally (p.o.) or intraduodenally (i.d.) to rats, rabbits and dogs, it caused a significant increase in the output volume of respiratory tract fluid (RTF). It was almost as potent as bromhexine, but its pattern of increasing RTF was different from that of bromhexine. The increase in the serous ingredient of RTF after BR-222 administration seemed to be more remarkable than that after bromhexine treatment, though both drugs had no influences on the component ratio of glucose or protein in the RTF of dogs. 2. BR-222 at 10 and 20 mg/kg (i.d.) showed a tendency to reduce the viscosity of RTF in anesthetized dogs and so did bromhexine. A dose of 10 mg/kg (i.d.) of BR-222 also showed a tendency to reduce the viscosity of sputum obtained from the SO2-exposed rabbits. 3. A dose of 6 mg/kg (i.m.) of BR-222 caused a significant increase in the mucociliary transport rate in unanesthetized pigeons; in contrast with this, bromhexine caused a slight decrease. 4. Both drugs given orally showed no antitussive effects when examined by the "coughing dog" method.

Animals↗
PubMed1983

Clinical aspects on bacterial infections in the upper respiratory tract.

Acute respiratory tract infections represent the major cause of morbidity in younger age groups. Most of these infections involve the upper respiratory tract. The frequency of respiratory tract infections vary not only with age, but also with season of the year and the epidemiological situation. Surveys of the incidence and aetiology of these infections must therefore cover large populations during relatively long periods of time. In the developed countries, the mortality in respiratory tract infections in patients below the age of 60 years is low, while it increases markedly in elderly patients, mainly due to involvement of the lower respiratory tract. Aetiologically, viral infections dominate but bacterial pathogens often cause pharyngitis/tonsillitis, otitis media and sinusitis. In longstanding cough in children, Branhamella catarrhalis has been found to be a pathogen of probably high significance. Other factors increasing the clinical importance of colonisation of the upper respiratory tract with potentially pathogenic bacterial species, are various immune defects, especially reduced IgA production, and granulocytopenia. In the latter case, Gram-negative bacteria seem to be more pathogenic than Gram-positive ones. The clinical differentiation between viral and bacterial upper respiratory tract infections is difficult and sometimes not possible. However, based on the knowledge that acute tracheitis, laryngitis and common cold are normally caused by viral agents, it seems reasonable not to use antibiotics for those patients.

Acute Disease↗
PubMed1995

[Respiratory tract infection and respiratory syncytial virus in young infants].

We investigated the role of respiratory syncytial virus (RSV) in respiratory tract infections of up-to-3-months old infants. This prospective study was carried out from April 1993 to March 1994. Detection of RSV antigen in nasopharyngeal specimens was done by enzyme immunoassay using TESTPACK RSV at our out patient clinic. During this study period, 65 young infants with respiratory tract infection visited our clinic. Seventeen patients (26%) were diagnosed as having RSV infection. Fifteen out of the 17 infants with RSV infection were observed in spring and winter. Fourteen out of the 17 infants with RSV infection had acute bronchiolitis or pneumonia. In contrast to RSV infection, only three patients out of the 48 infants with non-RSV infection had lower respiratory tract infection. In conclusion, the majority of young infants infected with RSV suffered from bronchiolitis or pneumonia.

Antigens, Viral↗
PubMed2003

Physiologically-based kinetic modeling of vapours toxic to the respiratory tract.

The respiratory tract is frequently identified as a site of toxicity for inhaled xenobiotic chemicals. Usually, these observations come from controlled animal studies. For these studies to be of quantitative value to human health risk assessment, species-specific factors governing dosimetry of inhaled substances must be taken into account. Toxicokinetics of vapours in the respiratory tract are defined by absorption, distribution, metabolism, and excretion, as they are in other tissues; however, these concepts take on new dimensions when considering respiratory tract toxicants, especially those that elicit portal of entry effects by directly interacting with the tissue lining the respiratory tract. Species-specific factors related to anatomy, physiology and biochemistry govern inter-species extrapolation of toxicokinetics. This article discusses critical factors of respiratory tract kinetics that should be considered when developing physiological-based toxicokinetic (PBTK) models for inhaled vapours. Important considerations such as impact of regional airflow-delivery, water solubility, reactivity, and rates of local biotransformation on respiratory tract tissue dosimetry are highlighted. These factors can be accounted for only to a limited extent when using default approaches to extrapolate dosimetry of inhaled substances across species. On the other hand, PBTK modeling has the flexibility to accommodate many of the critical determinants of respiratory tract toxicity. PBTK models can also help identify the most critical toxicokinetic data necessary to replace defaults. PBTK approaches have led to more informed estimates of human target tissue dose, and therefore human health risk, especially where these risk assessments have been based on extrapolation of animal dosimetry studies. Experience derived from the development of more intensive case studies have, in turn, enabled simplified approaches to the use of PBTK modeling for respiratory tract toxicants. Whether simplified or highly complex, PBTK modeling approaches are proven to be of great utility to risk assesors interested in applying quantitative information to informed risk assessment evaluations.

Animals↗
PubMed1974

Cell-mediated immunity after bacterial infection of the lower respiratory tract.

Lower respiratory tract and systemic cell-mediated immunity have been studied in rabbits after infection with Listeria monocytogenes or Diplococcus pneumoniae. Respiratory tract cell-mediated immunity was evaluated by direct and indirect assays of migration inhibitory factor (MIF) production. Systemic delayed hypersensitivity was determined by means of intradermal testing with appropriate antigens. Aerosol exposure to listeria was followed by markedly increased numbers of free lower respiratory tract cells. These cells manifested antigen-stimulated inhibition of migration (mean inhibition of migration = 30.4%). Pneumococcal pneumonia was associated with similar but less dramatic changes. Intravenous administration of organisms was uncommonly followed by inhibition of lower respiratory tract cells in direct migration assays. Fractionated MIF, as well as crude supernates of antigen-stimulated lower respiratory tract and lymph node lymphocytes from animals exposed to listeria aerosols, caused inhibition of normal alveolar macrophage migration. MIF, produced by lymph node lymphocytes, has a molecular weight of approximately 65,000 and is inactivated by chymotrypsin or neuraminidase. Delayed dermal hypersensitivity to listeria antigen was observed in 54 of 55 animals exposed to listeria aerosols and in all 9 animals infected by the intravenous route. Delayed dermal reactions to pneumococcal sonicate antigen (but not capsular polysaccharide) followed D. pneumoniae respiratory tract infection in 19 of 28 animals, and was elicited in 5 of 6 animals after intravenous infection. Both local (macrophage migration inhibition) and systemic delayed hypersensitivity followed bacterial infection of the lower respiratory tract. MIF activity was shown to be one mechanism for inhibition of alveolar macrophage migration.

Animals↗