Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RESPIRATORY TRACT”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed2002

The continuing challenge of lower respiratory tract infections.

Lower respiratory tract infections have been a major cause of morbidity and mortality among humans since the dawn of history. The initial hope that the era of antibiotics would remove this scourge has been replaced by the more realistic view that although antimicrobial agents represent a major therapeutic advance, they have not yet solved all of the problems of lower respiratory tract infections. The pneumococcus, for example, causes mortality in a certain number of patients despite antimicrobial therapy. An even greater challenge is being imposed by the emergence of antimicrobial resistance among important bacterial pathogens, especially Streptococcus pneumoniae.

Centers for Disease Control and Prevention, U.S.↗
PubMed2005

Altered function in CD8+ T cells following paramyxovirus infection of the respiratory tract.

For many respiratory pathogens, CD8+ T cells have been shown to play a critical role in clearance. However, there are still many unanswered questions with regard to the factors that promote the most efficacious immune response and the potential for immunoregulation of effector cells at the local site of infection. We have used infection of the respiratory tract with the model paramyxovirus simian virus 5 (SV5) to study CD8+ T-cell responses in the lung. For the present study, we report that over time a population of nonresponsive, virus-specific CD8+ T cells emerged in the lung, culminating in a lack of function in approximately 85% of cells specific for the immunodominant epitope from the viral matrix (M) protein by day 40 postinfection. Concurrent with the induction of nonresponsiveness, virus-specific cells that retained function at later times postinfection exhibited an increased requirement for CD8 engagement. This change was coupled with a nearly complete loss of functional phosphoprotein-specific cells, a response previously shown to be almost exclusively CD8 independent. These studies add to the growing evidence for immune dysregulation following viral infection of the respiratory tract.

Animals↗
PubMed1995

Role of inflammation in respiratory tract infections.

In respiratory tract infections, leukocytes are recruited to the lungs, where they help remove invading organisms through phagocytic clearance. In some instances, however, the normal inflammatory response may be as destructive as it is defensive. The neutrophils secrete a proteolytic enzyme, neutrophil elastase, which has emerged as a major culprit in the pathogenesis of inflammatory airway disease. This enzyme has been found to strip the bronchial epithelium, reduce ciliary beating, and stimulate excess mucus secretion, leading to mucus retention, bacterial proliferation, and recurrent infections. Neutrophil elastase also stimulates epithelial cell interleukin-8 secretion and produces other chemoattractant cleavage products that lead to further neutrophil recruitment. It also impairs host defenses by damaging the major opsonophagocytic receptor on the neutrophil and by weakening the efficacy of immunoglobulins. For this reason, an important goal in the treatment of respiratory tract infections should be to prevent or shorten the duration of neutrophil elastase release. A number of different approaches have been proposed or attempted in an effort to modulate the proteinase burden. These include direct inhibition of elastase and interference with the recruitment, adherence, and degranulation of neutrophils. An even more fundamental approach would start in the bone marrow, where attempts might be made to modulate or modify neutrophil precursors so as to limit the destructive potential of the mature neutrophils.

Bone Marrow Cells↗
PubMed2003

Effectiveness of influenza vaccination of children with recurrent respiratory tract infections in reducing respiratory-related morbidity within the households.

To evaluate the effectiveness of influenza vaccination in reducing respiratory-related morbidity among children with recurrent respiratory tract infections (RRTIs) and their household contacts, 127 children aged 6 months-9 years (78 males; median age, 3.7 years) with a history of RRTIs (>/=6 episodes per year if aged >/=3 years; >/=8 episodes per year if aged <3 years) were randomized to receive the intranasal virosomal influenza vaccine (n=64 with 176 household contacts) or a control placebo (n=63 with 173 household contacts). During influenza season, the vaccinated children had fewer respiratory infections, febrile respiratory illnesses, prescribed antibiotics and antipyretics, and missed school days than the controls, and similar benefits and a reduction in the loss of parental work were observed among their household contacts. This study shows that the benefits of influenza vaccination extend to children with RRTIs and their family members and encourages to recommend its use in such children.

Administration, Intranasal↗
PubMed1992

Antibiotic susceptibility of upper respiratory tract pathogens in Sweden: a seven year follow-up study including loracarbef. Swedish Respiratory Tract Study Group.

The antibiotic susceptibility of Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pyogenes and Streptococcus pneumoniae was investigated in five different geographical areas of Sweden in 1990 and compared with results from similar investigations performed in 1983 and 1986. Tests on 100 isolates per species and laboratory were performed by the disk diffusion method, and 10% of the strains plus all resistant ones were sent to the central laboratory for determination of MICs of ampicillin, phenoxymethylpenicillin, cefaclor, loracarbef, erythromycin, tetracycline and trimethoprim/sulfamethoxazole. Beta-lactamase production was found in 7% of H. influenzae and 71% of M. catarrhalis, and reduced susceptibility to penicillin in 3% of S. pneumoniae. Low frequencies (1-3%) of tetracycline resistance were found in H. influenzae and in the 2 streptococcal species, in which also less than 1% of the strains were resistant to erythromycin. Resistance to trimethoprim/sulfamethoxazole occurred in 7% (range 3-14%) of H. influenzae and in 3% of S. pneumoniae. Cefaclor was active against all streptococci except against S. pneumoniae with reduced susceptibility to penicillin. It was active against beta-lactamase negative strains of M. catarrhalis but had, according to the SIR-system, intermediate activity against H. influenzae. Loracarbef was twice as active as cefaclor against H. influenzae but equally active against the 3 other species tested.

Cephalosporins↗
PubMed1994

Oxidants, antioxidants, and respiratory tract lining fluids.

Respiratory tract lining fluids (RTLFs) are a heterogeneous group of substances covering the respiratory tract epithelial cells (RTECs) from nasal mucosa to alveoli. Antioxidant contained in the RTLFs can be expected to provide an initial defense against inhaled environmental toxins. The major antioxidants in RTLF include mucin, uric acid, protein (largely albumin), ascorbic acid, and reduced glutathione (GSH). RTLF antioxidants can be augmented by such processes as transudation/exudation of plasma constituents; RTEC secretory processes, including glandular mucus secretion; and cellular antioxidants derived from lysis of RTECs and of inflammatory cells. The antioxidant composition of RTLFs and their role in modulating normal and pathophysiologic RTEC functions under conditions of oxidative stress are yet to be fully characterized.

Animals↗
PubMed1989

A severe outbreak of respiratory tract disease associated with bovine respiratory syncytial virus probably enhanced by vaccination with modified live vaccine.

A severe outbreak of respiratory tract disease associated with bovine respiratory syncytial virus (BRSV) on a large beef-fattening farm is described. The outbreak started two days after five- to seven-month-old calves were vaccinated with a modified live BRSV vaccine. The disease ran a very severe course among five- to seven-month-old vaccinated calves, but disease was absent in eight-month-old an older non-vaccinated calves. The presence of IgM antibodies in sera of non-vaccinated calves indicated that BRSV was spreading on the farm between two to 15 days before the day of vaccination. The data indicate that vaccination with modified live vaccine during the course of a natural infection may enhance the severity of disease. The possible pathogenesis of the disease is discussed.

Animals↗
PubMed1994

[Cohort study of respiratory tract diseases and lung function in school children in southwest Germany. 2. Regional influences on respiratory tract diseases in Mannheim and the Freiburg area].

A prospective cohort study on 8124 schoolchildren aged 8 to 16 was conducted during the years 1977, 1979 and 1985 in Mannheim and two regions near Freiburg (Breisgau and the Black Forest). The objective of this part of the analysis was to investigate the regional differences in respiratory symptoms due to air pollution. Results are presented of 5726 children who had been living in those regions for at least five years at the times of interview. We have analysed 11 respiratory symptoms and two scores, measuring the tendency to infectious and asthmatic diseases, by logistic regression. Comparing the children living 1977 in Mannheim or the Breisgau to those living in the Black Forest the Relative Risks (Odds Ratios) of respiratory symptoms are in the range of 1.26-1.85 and 1.21-1.96 respectively. The results for the year 1979 are similar. In 1985 the regional effect has become smaller and no difference can be observed between Breisgau and the Black Forest. The infect score comprises bronchitis, inflamed throat with fever and sinusitis. The Relative Risk of an increased score decreases from 1.67 in 1977 to 1.65 in 1979 and 1.35 in 1985 in Mannheim and from 1.40 to 1.28 and 1.05 respectively in the Breisgau. The results of asthma and asthma symptoms are not homogeneous. In the Breisgau 1977 and 1979 the Relative Risk of an increased asthma score is slightly higher compared to the Black Forest. Allergies of the skin are reported more often in Mannheim than in the other areas. The Relative Risks of infectious respiratory symptoms and diseases agree spatially and temporarily well with the pattern of SO2 concentration. SO2 may be interpreted as an indicator for air pollution by power plants, industry and domestic heating.

Adolescent↗
PubMed1974

Acute Newcastle viral infection of the upper respiratory tract of the chicken. I. A model for the study of environmental factors on upper respiratory tract infection.

Acute Newcastle disease virus infection following intranasal inoculation of chicks with a mesogenic strain of the virus produced a localized infection of the middle turbinate which was histologically demonstrable 18 hours after inoculation. There was destruction of mucous cells of individual acini in the under surface of the middle turbinate, and the infection rapidly spread to ciliated and goblet cells and to neighboring acini. By day 2 there was simultaneous remodeling of the mucosa, continued destruction and inflammatory infiltration and frequent loss of cartilage basophilia. By day 3 polymorphonuclear cells almost disappeared, epithelial mitoses commenced, and lymphocyte infiltration intensified; the plasma cells normally present along the lateral nasal gland ducts were often destroyed, very occasionally the glands themselves were destroyed. By days 5 and 6 inflammation greatly decreased, and by day 8 the mucociliated epithelium was essentially normal. The infection is sequentially comparable to acute mild rhinitis of man.

Administration, Intranasal↗
PubMed1995

Expression and distribution of cell-membrane complement regulatory glycoproteins along the human respiratory tract.

Complement in the human respiratory tract protects the host from invading microorganisms and from other inhaled insults. However, complement may also lyse the host's respiratory tract cells, leading to tissue injury. In many extrapulmonic tissues, cells express cell-membrane complement regulatory glycoproteins that protect the cells from complement-induced lysis. To determine whether these glycoproteins are expressed in human respiratory tract tissue, we studied tissue biopsies of healthy and diseased human respiratory tract from nose to alveoli for the presence of four cell-membrane complement regulatory glycoproteins (membrane cofactor protein [MCP], decay-accelerating factor [DAF], CD59, and complement receptor type 1 [CR1]) using an immunoperoxidase technique. In addition, to establish a model for in vitro studies of these glycoproteins in respiratory cells, we studied whether they are expressed in cultured nasal epithelial cells, using the same technique. Altogether, 26 tissue specimens from 22 patients were studied. We found that normal human respiratory tract from nose to alveoli express MCP, DAF, and CD59, but not CR1, and that this expression increases in inflammation and in lung cancer. In addition, expression in nasal epithelial cells is retained under cell culture conditions. These findings suggest that human respiratory tract tissue may regulate complement activation on its surface in order to avoid self-injury. We propose that imbalances in the mechanism that regulates cell-membrane complement may predispose the respiratory tract to tissue injury and disease, and that iatrogenic modulation of such imbalances may help to prevent these adverse consequences.

Adolescent↗
PubMed1992

[Significance of exposure of workers in the tanning industry and the prevalence of upper respiratory tract diseases].

Respiratory diseases are in prevalence under the other diseases in industry of leather. The exposition to the chemical irritances like bensen and toluene is very important, because a short exposition gives early symptoms. We found in 54% of examined population pathologic ORL cases in a sense of hypertrophic and atrophic forms rhinitis and pharyngitis. Bacterial flora is pathologic in 20% of examined workers and comparing positive bacteriologic form between nose and pharynges we found infections of mucose of nose more frequent than the throat. The occupational atmosphere and its microclime is very important in pathology of upper respiratory diseases. It is etiological factor in morphological changes of the respiratory mucosas. At the end, we can say that the ordinary monitoring which contains monitoring of working place, and biologic monitoring which means ORL, bacteriological, biochemical and toxicologic examinations must be regulated.

Humans↗
PubMedDate not supplied

[Current approaches to the clinical virologic diagnosis of viral respiratory tract infections].

Respiratory viruses (respiratory syncytial virus, influenza virus type A and B, parainfluenza virus and adenovirus) can cause a wide variety of human disease. Viral respiratory diseases in adults and children cause significant morbidity and mortality. Proper and rapid diagnosis of these etiological agents is necessary for the appropriate use of effective antiviral drugs and to decrease unnecessary antibiotic therapy. Many virology laboratories detect respiratory viruses by inoculating conventional cell culture tubes with respiratory samples and then examining for cytopathic effect or hemadsorption. However, this procedure can require many days or even weeks for viral detection and identification, providing culture results to clinicians in a period of time that may not be clinically useful. Laboratory diagnosis of respiratory virus infections has become easier and more rapid with the use of immunofluorescent antibody tests, shell vial culture methods, and molecular biological assays. In this review article, the specificities and sensitivities of these assays were compared on the basis of recent studies, and the favorable ones for the routine diagnosis were updated.

Adenovirus Infections, Human↗
PubMed1992

[Prospects and indications for the prevention of respiratory tract tumors].

Respiratory cancers are suitable targets for primary prevention, since their causes are largely known and can be eliminated. Reasonable short-term objectives include the reduction of tobacco use (and alcohol abuse), the control of exposure to carcinogens in the workplace, as well as the reduction of air pollution in the general environment. The International Agency for Research on Cancer has estimated that in countries like Italy the elimination of cigarette smoking could reduce larynx cancer by 85% (if accompanied by a decrease in alcohol consumption), and lung cancer by 80% in males and 60% in females. An almost complete elimination of exposure to carcinogens in the workplace could potentially reduce lung cancer by 10%, whereas eliminating exposure to asbestos could certainly reduce pleural cancer by more than 50%. The proportion of lung cancer attributable to pollution in the general environment is unclear. Preventive measures require legislative support. Since October 1991, stores throughout Italy, in compliance with a new law, started carrying the first cigarette packages that included warnings against the hazards of smoking. Not since Law 584 of 1975, which forbids smoking in public places, has such an important legislative measure been passed. As a consequence of Law 584, smoking in many public places (e.g. movie theaters and, more recently, domestic flights) is today unthinkable, and these restrictions have been widely integrated into the Italian way of life. In developed countries, there is no doubt that the reduction of cancer due to the elimination of tobacco would be greater than that due to eliminating exposure to risk factors in the workplace.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗
PubMed1993

[State of pulmonary surfactant and hemodynamics of lesser blood circulation in Donets Basin coal miners during development of dust-induced respiratory tract diseases].

Respiratory diseases caused by dust in coal miners and high-risk group are manifested by accumulation of low surface-active surfactant masses, which thicken alveolar-capillary membrane, thus the smallest bronchi and alveoli collapse and diffusion of oxygen across blood-gas barrier becomes inadequate. Respiratory hypoxemia leads to reflectory construction of pulmonary arterioles, hence pulmonary hypertension occurs and cuts down blood supply to middle and lower portions of lungs, where dust is the most likely to invade. The blood supply is therefore shunted to the upper portions of lungs, which is compensatory. The stated changes appear at early stages of occupational respiratory diseases in miners.

Adult↗