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 1,027 records · Page 57Linked to original sources
PubMed1995

[Dirithromycin in the treatment of infections of the lower respiratory tract].

Good results of the treatment of patients with lower respiratory tract infections with dirithromycin (Eli Lilly, USA), a new semisynthetic macrolide, were recorded. The trial included 15 patients: 6 with acute bronchitis (AB) and 9 with exacerbation of chronic bronchitis (AB) and 9 with exacerbation of chronic bronchitis (ECB). The antibiotic was administered orally in a single dose of 500 mg once a day for 7 days. The treatment efficacy was estimated by the clinical results and laboratory findings. The sputum specimens were investigated bacteriologically with testing the microflora for the drug susceptibility by using the diffusion disks. 50 per cent of the patients with AB isolated Streptococcus viridans with low (the diameter of the growth inhibition zones < 16 mm) and intermediate (16-17 mm) susceptibility to the antibiotic, 33.3 per cent of the patients isolated highly susceptible (19 mm) strains of Str. pneumonia and 16.7 per cent of the patients isolated resistant (15 mm) strains of Staphylococcus epidermidis. Highly susceptible (17-19 mm) strains of Haemophilus influenzae and Str. viridans were isolated respectively from 55.5 and 45.5 per cent of the patients with ECB. In 4 patients with ECB a clinical improvement of the state was recorded. In the other patients with AB and ECB the recovery was stated. The bacteriological tests revealed a new pathogen in 2 patients with ECB and the failure of the treatment in another 2 patients with ECB. In all the other patients the pathogen was shown to be eradicated. In the patients isolating the new pathogen the symptomatic recovery was stated in the posttherapeutic period. Therefore, diritromycin proved to be efficient in 13 out of the 15 patients with lower respiratory tract infections. It should be noted that the drug tolerance was excellent. None of the patients showed any adverse reactions.

Acute Disease↗
PubMed1979

Collagenase in the lower respiratory tract of patients with idiopathic pulmonary fibrosis.

To test the hypothesis that idiopathic pulmonary fibrosis (IPF) is mediated through collagenase present in the lower respiratory tract, we used the fiberoptic bronchoscope to obtain fluid from the lower respiratory tract of 24 patients with IPF, 18 controls and nine patients with sarcoidosis. The fluid was analyzed for a variety of enzymes, including collagenase. Fifteen of 21 patients with IPF showed collagenase activity, whereas normal controls and patients with sarcoidosis showed none (P greater than 0.001, for all comparisons). In two patients with IPF who were re-evaluated after eight to 24 months, the collagenase activity was persistent. Fluid from patients with IPF also contained elevated levels of a non-specific neutral protease (P greater than 0.01 compared with controls), but there was no elastase activity in fluid from patients with IPF or from controls. The collagenase found in lavage fluid in IPF cleaved lung collagen into collagenase-specific TCA and TCB fragments. We conclude that in IPF the collagen of the lung is subjected to sustained lysis, followed by disordered resynthesis, and that the presence of active collagenase in the lower respiratory tract is a specific feature of the alveolitis associated with this disease.

Adult↗
PubMed2003

[Application of the acute physiology and chronic health evaluation II score system to patients with infection of Pseudomonas aeruginosa in lower respiratory tract in intensive care unit].

OBJECTIVE: To predict the infection and evaluate the severity of illness and prognosis for patients with infection of Pseudomonas aeruginosa (PA) in lower respiratory tract in intensive care unit (ICU) with the acute physiology and chronic health evaluation II (APACHE II). METHODS: The clinical data of 122 cases with infection of PA in lower respiratory tract were compared and studied. These data were evaluated with APACHE II score system according to Knaus method. RESULTS: APACHE II scores of the 29 nonsurvivors were significantly higher than that of 93 survivors (18.78+/-7.13 vs. 11.70+/-5.79, t=5.43, P<0.01). The patients with coinfections other than PA had a higher APACHE II score (14.76+/-6.89 vs. 10.08+/-6.14, P<0.01), a higher mortality (27.91 percent vs. 13.89 percent, P<0.01), and more days of stay in ICU [(28.47+/-23.59) days vs. (16.64+/-21.19) days] than those without. Patients with severe pneumonia had higher APACHE II scores (15.57+/-6.97 vs. 11.81+/-6.03) and poorer prognosis (39.22 percent vs. 12.68 percent) than those without. For all patients, when the APACHE II scores became higher and higher, the outcome became poorer and poorer, and the mortality higher and higher, and the percentage of severe pneumonia higher and higher. There was a significant correlation between APACHE II score and actual mortality (r=0.75, P<0.01) and predicted mortality (r=0.81, P<0.01). Actual and predicted mortality increased along with the increase in APACHE II scores by 5 scores. The sensitivity and positive rate of predicted mortality was 100.00 percent and 86.72 percent respectively. CONCLUSION: APACHE II score system is highly valuable in predicting the infection and evaluating the severity of illness and prognosis in patients with infection of PA in lower respiratory tract in ICU.

APACHE↗
PubMed1975

Inhalation experiments with 14C-labelled cigarette smoke. II. The distribution of cigarette smoke particles in the hamster respiratory tract after exposure in two different smoking systems.

Male and female Syrian golden hamsters were exposed to the smoke of [14C]dotriacontane-16,17 ([14C]DOT)-labelled cigarettes in 2 different exposure systems. These 2 systems differed in terms of the smoke concentration drawn into the exposure chamber. To compare the effectiveness of the exposure systems, the inhaled dose of 14C-labelled cigarette smoke was determined in the different parts of the hamster respiratory tract by liquid scintillation counting. About 6 times more smoke particles were deposited in the respiratory tract after exposure to high smoke concentration with intermittent puffs of fresh air (closed system) than after exposure to smoke diluted with air (open system). About 80% of the diluted smoke reached the bronchi and lung compared to approximately 60% of the concentrated smoke. The remainder of the dose was trapped in the upper respiratory tract, mainly by the nose and larynx. Additionally, in the open system the total dose of inhaled smoke was dependent upon the position in the exposure chamber. The results are discussed with respect to the use of the exposure systems for chronic cigarette smoke inhalation studies in experimental respiratory tract carcinogenesis.

Animals↗
PubMed1982

Histamine in nasal secretions and serum may be elevated during viral respiratory tract infections.

This study investigated histamine concentration in nasal secretions from children who had viral respiratory tract infection. It demonstrated that (1) there may be appreciable histamine in nasal secretions during viral respiratory tract infection; (2) concentration of histamine in serum may be elevated at the same time; and (3) children with past medical or family history of atopy had more histamine in nasal secretions during viral infections than did nonatopic children.

Bronchiolitis, Viral↗
PubMed1996

The effect of inhaled and intranasal sodium cromoglycate on symptoms of upper respiratory tract infections.

BACKGROUND: A well established drug for the treatment of asthma and allergy, sodium cromoglycate, was found in open trials to be useful as a symptomatic treatment for upper respiratory tract infections. OBJECTIVE: To compare the efficacy of inhaled and intranasal sodium cromoglycate and matching placebos on the symptoms of upper respiratory tract infections. METHODS: Adult subjects with symptoms of runny nose, throat pain, or cough for less than 24 h were recruited. They were treated for 7 days using a randomized, double-blind, placebo-controlled, group comparative design. The medication given was: sodium cromoglycate dry powder 20 mg per inhalation in spincaps; sodium cromoglycate aqueous nasal spray delivering 5.2 mg per dose; or matching placebo as dry powder and nasal spray. One spincap and one spray per nostril were taken every 2 h during waking hours on days 1 and 2 and then four times daily on days 3-7. Severity of nine symptoms (general malaise, body aches and pains, chills and shivering, sneezing, nasal running, nasal blocking, sore throat, cough and voice disturbance) was recorded twice daily by subjects on diary cards, using a scale of 0 (absent) to 3 (severe). RESULTS: The study was conducted between February and April 1993. One hundred and eighteen patients aged 21-63 years (mean 41 years) were included. Symptoms resolved faster (P < 0.001) and the severity in the last three days of treatment was significantly less in patients treated with sodium cromoglycate than with placebo (P < 0.05-day 5; P < 0.01-day 6; P < 0.001-day 7). Side effects were local and mild and did not differ between the treatment groups. CONCLUSION: Sodium cromoglycate administered both by inhalation and intranasally is an effective treatment for the symptoms of upper respiratory tract infection. Its combined safety and efficacy would make it an acceptable form of treatment for these conditions.

Administration, Inhalation↗
PubMed2005

Mechanical insufflation-exsufflation improves outcomes for neuromuscular disease patients with respiratory tract infections.

OBJECTIVES: The efficacy of mechanical insufflation-exsufflation, in addition to standard chest physical treatments, was investigated as a first-line intervention for patients with neuromuscular diseases with respiratory tract infections and airway mucous encumbrance. DESIGN: The short-term outcomes of 11 consecutive neuromuscular disease patients with respiratory tract infections and tracheobronchial mucous encumbrance who were administered mechanical insufflation-exsufflation and conventional chest physical treatments in an intensive care unit were compared with the outcomes of 16 historical matched controls who had received chest physical treatments alone. Treatment failure was defined as the need for cricothyroid "minitracheostomy" or endotracheal intubation, despite treatment. The number of subjects administered bronchoscopy-assisted aspiration during the hospital stay was also compared. RESULTS: Treatment failure was significantly lower (P < 0.05) in the mechanical insufflation-exsufflation group than in the conventional chest physical treatments group (2/11 vs. 10/16 cases). The use of bronchoscopy-assisted aspiration was similar in the two groups (5/11 vs. 6/16 cases). Mechanical insufflation-exsufflation did not produce serious side effects and was well tolerated by all subjects. CONCLUSIONS: Provision of mechanical insufflation-exsufflation in combination with standard chest physical treatments may improve the management of airway mucous encumbrance in neuromyopathic patients; its use should be included in the noninvasive approach to treatment of respiratory tract infections with impaired mucous clearance.

Adolescent↗
PubMed2002

Evolving resistance patterns in community-acquired respiratory tract pathogens: first results from the PROTEKT global surveillance study. Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin.

In recent years, antibacterial resistance among respiratory pathogens implicated in community-acquired respiratory tract infections (RTIs) has spread worldwide at an alarming rate. Thus, there is a pressing need for new antibacterials that retain activity against resistant organisms, have a low potential to select for resistance and do not induce cross-resistance. Telithromycin is the first of a new class of antibacterials - the ketolides - that have been designed specifically to overcome resistance among respiratory tract pathogens. This paper presents the first results of the PROTEKT study (Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin), a worldwide surveillance study initiated to chart the prevalence of important resistance phenotypes and genotypes and the comparative activity of telithromycin against such strains. Analysis of over 7,000 bacterial isolates by April 2001 has confirmed the notable prevalence of strains resistant to commonly prescribed RTI antibacterials for all the pathogens studied. Telithromycin demonstrates high activity against isolates of Streptococcus pneumoniae, irrespective of penicillin G, macrolide or fluoroquinolone resistance. Telithromycin is also highly active against other respiratory tract pathogens, including Streptococcus pyogenes and beta-lactamase-producing strains of Haemophilus influenzae and Moraxella catarrhalis. These data justify the assertion that telithromycin is a promising new candidate for the empirical treatment of community-acquired RTIs, particularly in the face of increasing antibacterial resistance.

Anti-Bacterial Agents↗
PubMed1990

Prevention of bacterial colonization of the respiratory tract and stomach of mechanically ventilated patients by a novel regimen of selective decontamination in combination with initial systemic cefotaxime.

A novel regimen of selective decontamination (SDD) with initial systemic cefotaxime prevented bacterial colonization of the oropharynx and stomach in mechanically ventilated patients. In a three-group study of all patients receiving prolonged mechanical ventilation, patients in control groups A and B received antibiotics only when infection was present. In group A, antibiotics that disturb colonization resistance (CR) were used. In group B, antibiotics use was restricted to antibiotics not affecting CR. Patients in group C received SDD, consisting of norfloxacin, polymyxin E and amphotericin B, administered via a gastric tube and applied to the oropharynx. Group C patients further received an initial five day course of cefotaxime, 500 mg tid. The lower respiratory tract was colonized with microorganisms on admission in about half of the patients, and this persisted in both control groups. In group C, lower respiratory tract colonization was eliminated in all patients after five days. In both control groups about 90% of the patients acquired microbial colonization of the oropharynx and stomach, mostly with Gram-negative bacilli. In group C, only 12% and 24% of the patients acquired colonization of the oropharynx and stomach respectively (P less than 0.001). The oropharynx and stomach were the major sources of microorganisms causing lower respiratory tract infection in both control groups. In group C, elimination of oropharyngeal and gastric colonization completely prevented lower respiratory tract infection from these sources.

Adult↗
PubMed1990

Interactions of xenobiotics in the respiratory tract following non-inhalation routes of exposure.

Compounds of highly variable structure may induce toxic effects and tumours in the respiratory tract following peroral or parenteral administration in experimental animals. Such compounds are used in industrial processes or may be present in the food as contaminants or pesticide residues. This review gives examples of selective metabolism and toxicity of chemicals in different segments of the respiratory tract. Many of these compounds require metabolic activation to exert toxicity. Accordingly, the susceptibility of the respiratory tract to the effects of such agents may be influenced by other compounds modulating the activity of activating xenobiotic metabolizing enzymes. Dietary factors may alter the susceptibility to experimental lung carcinogenesis also via other mechanisms. As concluded from experimental data, the human lung may be exposed to a wide array of potentially toxic compounds present in the diet or the environment. Such exposures may constitute confounding factors in low-risk lung cancer epidemiology.

Animals↗
PubMed1989

[Respiratory tract infections due to Mycoplasma pneumoniae in elementary school children; a case report].

Epidemic respiratory tract infections occurred among elementary school children in Hiroshima prefecture during June, July and August, 1987. Forty (59%) of 68 children who were enrolled in an elementary school were confirmed to have respiratory diseases during this period, ten of whom were hospitalized with diagnoses of pneumonias. Diagnoses of M. pneumoniae infection were made from secretions obtained by throat swabs, and by serological studies of blood specimens. Twenty-four (77%) of the 31 patients examined were confirmed to have M. pneumoniae infections. Twenty-three of them had upper respiratory tract infections with cough and fever; two had pneumonia, one with myringitis. PPLO-broth, SP-4 broth and diphasic medium were used for M. pneumoniae isolation. Among these, SP-4 broth proved to have the highest isolation rate.

Child↗
PubMed2026

Multidrug resistance and genomic characteristics of nontypeable Haemophilus influenzae isolates from the respiratory tract of pediatric patients.

UNLABELLED: Nontypeable Haemophilus influenzae (NTHi) is a common colonizer of the human upper respiratory tract and one of the major pathogens responsible for pediatric respiratory tract infections. Given the increasing severity of its multidrug resistance (MDR), this study comprehensively investigated the genomic characteristics of circulating NTHi isolated from sputum and bronchoalveolar lavage fluid (BALF). A total of 104 H. influenzae isolates (69 from sputum; 35 from BALF) were collected from pediatric patients between January 2024 and January 2025. All isolates underwent whole-genome sequencing and antimicrobial susceptibility testing, followed by core/pan-genome phylogenetic analysis, multilocus sequence typing (MLST), and resistome profiling. Among them, 103 were identified as NTHi. We identified 29 known sequence types (STs) and 10 novel STs, with ST-107 (14.4%), ST-57 (10.6%), and ST-11 (8.7%) being the major circulating lineages. However, core-genome phylogenetic analysis provided a more granular view of the genetic variation within these identical STs. All the isolates showed high resistance to ampicillin (98.1%) and cefuroxime (84.6%). Genomically, the multidrug efflux pump gene hmrM was ubiquitous (100%). Ampicillin resistance was predominantly driven by blaTEM-1 carriage (77.9%), with minor contributions from chromosomal ftsI mutations. Fifteen plasmid replicons were predicted from 25 isolates, which highly coincided with the carriage of blaTEM-1 and other acquired resistance genes. This study demonstrates that MDR in pediatric NTHi is primarily driven by acquired resistance genes and chromosomal mutations, with specific resistant clones persisting and enriching under clinical antibiotic pressures. These findings underscore the importance of continuous high-resolution genomic surveillance in guiding rational antibiotic stewardship. IMPORTANCE: This study highlights the critical importance of high-resolution genomic surveillance in managing pediatric nontypeable Haemophilus influenzae (NTHi) infections. By utilizing whole-genome sequencing, we uncovered the pathogen's highly dynamic population structure and complex multidrug resistance (MDR) mechanisms. Crucially, our findings reveal a strong, non-random coupling between core genomic architectures, virulence factors, and MDR elements, driven by dual environmental and pharmacological pressures. This "virulence-MDR" co-evolutionary trend underscores the persistent clinical threat of locally adapted high-risk clones. These findings provide important insights for guiding rational clinical antibiotic stewardship, optimizing treatment strategies, and improving regional infection control.

Humans↗
PubMed1975

Production of respiratory tract tumors in hamsters by benzo(a)pyrene.

Respiratory tumor induction was tested for the tumorigenic activity of benzo[a]pyrene alone. A group of 32 male and 28 female Syrian golden hamsters were given weekly intratracheal instillation of 1 mg of benzo[a]pyrene suspended in isotonic saline, for 30 weeks. Squamous cell carcinoma, adenocarcinoma, anaplastic carcinoma, adenoma, papilloma, and polyps were induced in the respiratory tract of hamsters. Tumor incidences were 42.3% in males and 57.7% in females. Respiratory carcinomas were inducible in hamsters by simple instillation of a low dose of benzo[a]pyrene without using a surface-active agent or carrier-dust. These findings may be useful as a standard data for cocarcinogenesis studies when using other modality combined with benzo[a]pyrene in experimental studies.

Adenocarcinoma↗
PubMedDate not supplied

Sputum cytologic diagnosis of upper respiratory tract cancer.

Sputum cytologic testing has been applied in the screening of high-risk individuals for presymptomatic lung cancer. This same screening procedure sometimes identifies patients with upper respiratory tract cancers and thereby may permit earlier treatment. Patients enrolled in the Mayo Lung Project undergo sputum cytologic and chest roentgenographic screening at four-month intervals and are compared with matched controls who are not intensively screened. Experience to date indicates an incidence rate of approximately 1 per 1,000 per year of cancer in the upper respiratory and alimentary passages among males more than 45 years old who are heavy cigarette smokers. This compares with a rate of approximately 4 per 1,000 per year of lung cancer. Recognition of early cancer of the upper respiratory tract is an additional benefit of screening for lung cancer. Since cigarette smoking represents an etiologic agent common to both upper and lower respiratory tract cancers, tumors should be searched for in both sites in this high-risk population.

Aged↗
PubMed1976

The class-specific immunoglobulin composition of fluids obtained from various levels of the canine respiratory tract.

Sensitive and specific radioimmunoassays capable of accurately measuring the three major classes of canine immunoglobulins in the 50 to 200 ng/ml range were developed. The concentrations of IgG, IgA, and IgM in samples of fluid obtained from various levels of the canine respiratory tract (stimulated saliva, tracheal washes, and bronchopulmonary lavage supernatants) and in serum were determined by using the radioimmunoassays. The composition of the immunoglobulin classes, expressed as per cent of the total immunoglobulin content of each sample, differed markedly among the respiratory tract-derived fluids and between respiratory fluids and serum. Pilocarpine-stimulated saliva contained predominantly IgA while bronchial washes contained predominantly IgG. The contents of IgA and IgG in tracheal washes were intermediate between those of stimulated saliva and bronchial washes. There appeared to be a progressive decrease in the content of IgA (83% to 19%) and a progressive increase in the content of the IgG (6.3% to 75%) as sampling proceeded from the upper to the lower respiratory tract. The mean IgG/IgA ratios were as follows: stimulated saliva, 0.1; tracheal washes, 2.1; bronchial washes, 4.1; and serum, 23.2. All respiratory tract-derived fluids contained small amounts of IgM. Local and systemic immunization with sheep erythrocytes failed to alter the per cent composition of immunoglobulins in bronchial washes during the primary immune response. The results demonstrate major differences in the composition of immunoglobulins derived from the upper as opposed to the lower respiratory tract. The findings suggest that functional differences may exist in the immunologic apparatus associated with various levels of the respiratory tract.

Animals↗
PubMed2001

Screening of the antibacterial effects of a variety of essential oils on respiratory tract pathogens, using a modified dilution assay method.

The purpose of this study was to examine the antibacterial effects of a wide variety of essential oils on major respiratory tract pathogens. The antibacterial activity of 14 essential oils and their major components was evaluated by agar-plate dilution assay under sealed conditions, with agar used as a stabilizer for homogeneous dispersion. Of the selected strains of four major bacteria causing respiratory tract infection, Haemophilus influenzae was most susceptible to the essential oils, followed by Streptococcus pneumoniae and Streptococcus pyogenes. Staphylococcus aureus was less susceptible. No cross-resistance was observed between penicillin-sensitive and penicillin-resistant S. pneumoniae. Escherichia coli, used as a control bacterium, showed the lowest susceptibility. Essential oils containing aldehyde or phenol as a major component showed the highest antibacterial activity, followed by the essential oils containing terpene alcohols. Other essential oils, containing terpene ketone, or ether, had much weaker activity, and an oil containing terpene hydrocarbon was inactive. Based on these findings, thyme (wild, red, and geraniol types), cinnamon bark, lemongrass, perilla, and peppermint oils were selected for further evaluation of their effects on respiratory tract infection.

Agar↗
PubMed2000

[Selection of bronchoscope type for removal of foreign bodies from the lower respiratory tract based on personal experience].

32 patients, in whom bronchoscopy was performed due to the removal of foreign body from the lower respiratory tract were described. Age of the patients clinical symptoms and a time lapse between aspiration and removal of foreign body from the lover respiratory tract and localization of foreign body in the particular bronchus were analysed. We conclude, that rigid bronchoscopy is still more useful and safe method of foreign body removing from the lower respiratory tract.

Adolescent↗
PubMed1997

Styrene-induced alterations in the respiratory tract of rats treated by inhalation or intraperitoneally.

Although exposure to styrene occurs primarily via inhalation, the action of this agent on the respiratory tract has scarcely been investigated. This article describes morphological and biochemical changes occurring in the respiratory tract of rats after either inhalation of styrene vapors (300 ppm, 6 h/d, 5 d/wk, for 2 wk) or systemic (ip) treatment with 40 or 400 mg/kg styrene for 3 consecutive days. Electron microscopy analysis showed diffuse cell damage involving the tracheal, bronchiolar, and alveolar epithelium. In the tracheal epithelium, several cell types were affected. Ciliated cells presented vacuolation, detachment of cilia, blebbing of the apical cytoplasm, and compound cilia. Most secretory cells showed scant secretory granules and blebbings. Dense bodies and fibrillary inclusions were seen in intermediate and basal cells. Styrene also caused alterations of cytoplasmic components in type II pneumocytes and bronchiolar cells as well as thickness of the alveolar wall. These abnormalities were accompanied by depletion of glutathione (GSH) in the lung tissue. Pneumotoxic effects of systemic administration of styrene were dose dependent and tended to be more severe than those seen in the animals exposed for longer periods to styrene by inhalation. Metabolic activation of styrene and subsequent cell damage induced by the reactive metabolite styrene oxide may be involved in the sequence of events culminating in the toxic insult to the respiratory tract.

Administration, Inhalation↗