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PubMed1991

Culture vs direct antigen assays for detection of microbial pathogens from lower respiratory tract specimens suspected of containing the respiratory syncytial virus.

Following the introduction of effective antiviral chemotherapy, rapid antigen assays have been utilized increasingly, instead of cell cultures, for detection of the respiratory syncytial virus from lower respiratory tract specimens. Because antigen assays, unlike cell culture, cannot amplify low levels of the virus to a detectable level, assay sensitivity is especially dependent on high-quality specimens. In addition, the assays are unable to detect other viruses or bacteria with which the patient may be infected. This review summarizes results from clinical studies of the performance of cell cultures and the more commonly used antigen assays, describes factors that may lead to false-positive or false-negative test results, and makes recommendations for the selection of procedures for the reliable detection of microbial pathogens from patients suspected of being infected with respiratory syncytial virus.

Antigens, Viral↗

PubMed1990

Evaluation of a selective medium for the isolation and differentiation of Haemophilus influenzae and Haemophilus parainfluenzae from the respiratory tract of chronic bronchitics.

Respiratory tract specimens from chronic bronchitic patients were cultured for Haemophilus species on conventional chocolate agar and a modified sucrose medium in order to determine the accuracy of the new medium in differentiating Haemophilus influenzae from Haemophilus parainfluenzae strains. Haemophilus influenzae biotypes II and III and Haemophilus parainfluenzae biotypes I and II were found to be the predominant strains isolated from the respiratory tract. The modified sucrose medium was found to be a rapid and reliable means of differentiating Haemophilus influenzae from Haemophilus parainfluenzae by sucrose fermentation, on initial isolation.

Bronchitis↗

PubMed1984

The comparative absorption and excretion of chemical vapors by the upper, lower, and intact respiratory tract of rats.

Upper respiratory tract (URT) absorption of several compounds with differing water solubilities and potentials to cause lesions of the nasal mucosa were studied in rats. Absorption of propylene glycol monomethyl ether (PGME), PGME acetate (PGMEAc), ethyl acrylate (EA), epichlorohydrin (EPI), styrene (STY), nitroethane (NE), ethylene dibromide (EDB), and methylene chloride (MeCl2) vapors by the isolated URT was compared to that by the isolated lower respiratory tract (LRT) and the intact animal. Nearly all PGME and PGMEAc and 30-70% of EA, EPI, STY, NE, and EDB were absorbed when passed through the URT. In general, similar levels were absorbed by both the isolated LRT and intact animal. It was estimated that intact animals received more than 90% of their total dose of PGME and PGMEAc, and 50% of EA, NE, EPI, and EDB via the URT. Further, the dosage per unit of surface area in the URT may be 5000-6000 times that of the LRT. However, the extent of URT absorption was not related to the ability to cause lesions of the nasal mucosa. Absorption of compounds by the URT was not a simple function of water solubility or of blood or water/air partitioning coefficients suggesting that a more complex mechanism for controlling absorption may exist. In one case, it was demonstrated that URT enzymatic activity could influence the absorption of certain compounds by the URT.

Absorption↗

PubMed1989

Mechanosensitive and beta-adrenergic control of the ciliary beat frequency of mammalian respiratory tract cells in culture.

Respiratory tract ciliated cells, obtained from the rabbit trachea and maintained in culture, were sensitive to mechanical stimulation. The mechanical deformation of the cell surface induced a rapid, but transient, increase in ciliary beat frequency. In addition, the beat frequency of these ciliated cells was also increased in a dose-dependent manner by the beta-adrenergic drug isoproterenol (10(-7) to 10(-4) M) and by the calcium ionophore A23187 (10(-6) and 10(-5) M). To determine if drug and mechanosensitive activation of ciliary beat frequency arise from a common or different cellular mechanism, we investigated the effect of mechanical stimulation on beat frequency in the presence of isoproterenol or A23187. In isoproterenol (10(-8) to 10(-4) M), none of the parameters used to describe the ciliary beat frequency response to mechanical stimulation was altered. In A23187 (10(-6) M or above), the magnitude of the beat frequency response was significantly reduced or almost abolished, suggesting that mechanical stimulation acts, like A23187, to increase ciliary beat frequency by increasing intracellular calcium. Lower concentrations of A23187 had no effect. These results suggest that respiratory tract ciliated cells have at least two independent mechanisms for the control of ciliary beat frequency: one probably utilizing calcium, the other probably cAMP.

Animals↗

PubMed2003

Human metapneumovirus in a haematopoietic stem cell transplant recipient with fatal lower respiratory tract disease.

Respiratory viruses are increasingly recognized as a cause of pneumonitis following haematopoietic stem cell transplantation (HSCT). However, frequently, no pathogen is identified in cases of suspected viral pneumonia. Recently, a previously undescribed paramyxovirus, designated 'human metapneumovirus' (hMPV), was isolated from children with respiratory illness. We have detected hMPV as the sole pathogen in the nasopharyngeal aspirate of an HSCT recipient who succumbed to progressive respiratory failure following an upper respiratory prodrome. This report highlights the importance of further studies to elucidate the role of hMPV in causing respiratory illnesses in the HSCT population.

Adult↗

PubMed2006

Etiologic diagnosis of adult bacterial pneumonia by culture and PCR applied to respiratory tract samples.

Respiratory culture and multiplex PCR for Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, and Chlamydophila pneumoniae were applied to sputum, nasopharyngeal swabs, and nasopharyngeal aspirates from 235 adult patients with community-acquired pneumonia and 113 controls. Both culture and multiplex PCR performed well with the different samples and appear to be useful as diagnostic tools.

Adolescent↗

PubMedDate not supplied

Some aspects of upper respiratory tract reflexes.

Respiratory and cardiovascular reflexes have been elicited from receptors in the nose and larynx in the anaesthetized dog. Cigarette smoke in the nose causes reflex apnoea, bradycardia and vasoconstriction, probably due to systemic absorption through the nose. Stimulation of laryngeal nerve also results in reflex apnoea, bradycardia, and limb vasoconstriction. When asphyxia supervenes due to apnoea, stimulation of the carotid body chemoreceptors occurs which normally cause, as primary effects, hyperpnoea and bradycardia. However, it has been shown that stimulation of the laryngeal receptors inhibits the carotid body respiratory reflex and facilitates the carotid body cardio-inhibitory reflex, the latter leading to temporary cardiac arrest. The clinical implications of this finding are discussed.

Animals↗

PubMed1989

[Effects of tobacco smoke applied on various levels of the respiratory tract].

The respiratory and cardiovascular reflex responses of tobacco smoke inhaled through an isolated larynx and directly into the lungs were studied in cats. The inhalation of tobacco smoke directly into the lungs showed the following: tachypnea (p less than 0.01), an increase in inspiratory and expiratory pleural pressure (p less than 0.01, p less than 0.001) with an increase in total lung resistance (p less than 0.01), a decrease in inspiratory and expiratory subglottic pressure (p less than 0.001, p less than 0.02) and an increase in mean arterial pressure (p less than 0.001) with a non significant slight increase of cardiac rate. The inhalation through an isolated larynx showed: bradypnea (p less than 0.01), a non significative decrease in inspiratory and expiratory pleural pressure with no changes in total lung resistance, and an increase in expiratory subglottic pressure (p less than 0.01) with no changes in inspiratory pressure accompanied by several glottic closures. No changes in arterial pressure and cardiac rate were observed. This study shows the existence of two respiratory reflex responses induced by tobacco smoke depending on the respiratory airway level application.

Animals↗

PubMed1995

[Histological structure of the distal segment of the respiratory tract].

The respiratory system consists of morphologically and functionally distinct sub-divisions-the air-conditioning part and respiratory portion is were O2 and CO2 exchange actually occurs across the delicate, very thin walls of the pulmonary alveoli. The final bifurcation of bronchiole yields terminal bronchiole. The epithelium is gradually reduced from ciliated columnar in the larger bronchioles to ciliated or non-ciliated low cuboidal in the terminal segment. Here non-ciliated Clara cells are plentiful. Only under EM one can clearly identify the lining cells of the alveoli: type I are squamous pneumocytes, type II are large granular alveolar cells and macrophages (dust cells). The hallmarks of pneumocytes type II are the numerous osmiophilic, lamellated inclusion bodies. In TEM there is evidence connecting these bodies with the production of stabilizing surface active material, which prevents the collapse of the alveoli; colled surfactant, different from that of the Clara cells.

Bronchi↗

PubMed2006

Frequent detection of bocavirus DNA in German children with respiratory tract infections.

BACKGROUND: In a substantial proportion of respiratory tract diseases of suspected infectious origin, the etiology is unknown. Some of these cases may be caused by the recently described human bocavirus (hBoV). The aim of this study was to investigate the frequency and the potential clinical relevance of hBoV in pediatric patients. METHODS: We tested 835 nasopharyngeal aspirates (NPA) obtained between 2002 and 2005 from pediatric in-patients with acute respiratory tract diseases at the University of Würzburg, Germany, for the presence of hBoV DNA. The specificity of positive PCR reactions was confirmed by sequencing. RESULTS: HBoV DNA was found in 87 (10.3 %) of the NPAs. The median age of the infants and children with hBoV infection was 1.8 years (mean age 2.0 years; range 18 days - 8 years). Infections with hBoV were found year-round, though most occurred in the winter months. Coinfections were found in 34 (39.1 %) of the hBoV positive samples. RSV, influenza A, and adenoviruses were most frequently detected as coinfecting agents. Sequence determination of the PCR products in the NP-1 region revealed high identity (99 %) between the nucleotide sequences obtained in different years and in comparison to the Swedish viruses ST1 and ST2. An association of hBoV with a distinct respiratory tract manifestation was not apparent. CONCLUSION: HBoV is frequently found in NPAs of hospitalized infants and children with acute respiratory tract diseases. Proving the clinical relevance of hBoV is challenging, because application of some of Koch's revised postulates is not possible. Because of the high rate of coinfections with hBoV and other respiratory tract pathogens, an association between hBoV and respiratory tract diseases remains unproven.

Adenoviruses, Human↗

PubMed1986

[Treatment of respiratory tract infections with imipenem/cilastatin in critical patients with respiratory insufficiency].

In an open prospective study the efficacy and tolerance of imipenem/cilastatin was investigated in 24 critically ill patients on mechanical ventilation with nosocomial respiratory tract infection. Nine patients had previously received antibiotic therapy, eight of them with various other beta-lactam antibiotics which had failed. Imipenem was given in a dose of 1-3 g/24 h over 5-37 (mean 11) days. Seven patients were additionally treated with aminoglycosides, one patient with erythromycin. Pseudomonas aeruginosa (n = 14), Staphylococcus aureus (n = 4), Haemophilus influenzae (n = 4) and Escherichia coli (n = 3) were the potential pathogens most frequently isolated from tracheo-bronchial secretions. All of the isolates were susceptible to imipenem. 91% of the infections without and 77% with involvement of P. aeruginosa were successfully treated. Two patients who had not responded to previous treatment succumbed to the consequences of progressive respiratory distress syndrome. All of the gram-positive and 85% of the gram-negative pathogens (Pseudomonas not included) were eliminated in the course of therapy. By contrast, 64% of the isolates of P. aeruginosa persisted; half of these became imipenem-resistant. Nine patients showed adverse reactions including one case of pseudomembranous colitis or laboratory abnormalities which were all reversible. Imipenem/cilastatin proved highly effective and was relatively well tolerated; it is suitable as a single agent for the initial treatment of nosocomial respiratory tract infections in ventilated patients, although only with limitations in cases of infection due to P. aeruginosa.

Adolescent↗

PubMed1998

Neoplasia of the respiratory tract.

Tumors of the equine respiratory tract occur infrequently. An accurate diagnosis of neoplasia of the respiratory tract is critical because the prognosis is usually grave. The clinical signs and diagnostic procedures are discussed for tumors of the nasal and paranasal sinuses, nasopharynx/larynx, guttural pouch and thorax including lung, pleura, and thymus.

Animals↗

PubMedDate not supplied

The role of viruses and Mycoplasma pneumoniae in lower respiratory tract infections in childhood.

Acute lower respiratory tract infections are one of the major causes of childhood morbidity and mortality in developing countries. This study was undertaken at Hacettepe University Children's Hospital to determine the role of viruses and Mycoplasma pneumoniae in respiratory tract infections in children. Eighty-three patients with lower respiratory tract infections were selected at random from among the children admitted to the hospital for evaluation of respiratory symptoms. Acute and convalescent serum samples were collected from all patients for the complement-fixation test and the following antigens were used: respiratory syncytial virus (RSV), adenovirus, parainfluenza virus Type 1, influenza viruses A and B, and Mycoplasma pneumoniae. The test was positive in 39 of 83 patients (47%), and RSV was the most frequent agent detected serologically (15.7%).

Acute Disease↗

PubMed1993

Chlamydial infection of the respiratory tract.

Chlamydial infection of the human respiratory tract was first described over 100 years ago, when outbreaks of psittacosis were linked to imported pet birds. The causative organism was identified subsequently as Chlamydia psittaci. However, C. pneumoniae, has also been recognised recently as an important cause of human respiratory tract infection. Approximately 300 cases of human chlamydial respiratory tract infection are reported to CDSC each year, mainly in adults aged 15 to 44 years. A prospective study in Cambridgeshire showed that 76% of cases were associated with C. psittaci and 24% of cases with C. pneumoniae. There are several laboratory tests for diagnosing chlamydial infections. The complement fixation test is still the most commonly used but it cannot distinguish between different species of chlamydiae. Other serological tests, which can distinguish between different species, are only carried out in specialist laboratories. C. pneumoniae is particularly difficult to culture and C. psittaci is a grade 3 pathogen. Chlamydial antigens can be detected in sputum samples but these are not routinely sought in human chlamydial respiratory infections. There is a need to improve diagnostic techniques because rapid and accurate diagnosis leads to the use of appropriate antibiotics and will help to elucidate the epidemiology of these infections.

Adolescent↗

PubMed1976

Spontaneous tumors and common diseases in two colonies of Syrian hamsters. II. Respiratory tract and digestive system.

Spontaneous respiratory tract neoplasms in Syrian hamsters occurred in almost equal frequencies in two colonies: 3% in the Eppley Colony (EC) and 3.6% in the Hannover Colony (HC). Neoplasms were in the nasal cavity, trachea, and lungs, and most were benign; however, 2 adenocarcinomas of the nasal cavity (EC) and 1 adenocarcinoma of the larynx (HC) were found. The incidence of digestive tract tumors showed a more marked difference than that of the respiratory tract: 7% in the EC and 23% in the HC. Digestive tract tumors accounted for 15 and 41% of all tumors in the EC and HC, respectively. All EC digestive tract neoplasms were benign and occurred mostly in males; 19 (83%) were forestomach papillomas and the remaining 4 )17%) were liver hemangioendotheliomas (2) and pancreatic duct adenomas (2). In the HC, almost 50% of the digestive tract neoplasms were malignant and most frequent in females. These tumours include 19(42%) intestinal adenocarcinomas, 18(40%) liver neoplasms (hemangioendotheliomas, cholangiomas, cholangiocarcinomas), 5 (13%) forestomach papillomas, and 2 (4%) gallbladder polyps. The morphology of these neoplasms was reported.

Adenocarcinoma↗

PubMed2006

[Monitoring of neopterin and INF-gamma in children with recurrent respiratory tract infection].

The upper and lover respiratory tract infections are usually mild and self-limited. Owing to their frequency recurrent upper and lower respiratory tract infection in children and adults constitute a major global health problem. The goal of our study was to observe 30 children with recurrent respiratory tract infection, 17 boy and 13 girl, they were treated with Ribomunyl. The control group consisted of 15 children who received only basic therapy (10 boys and 5 girls). The age of the children ranged between 8 months and 6 years. The study was conducted by the simply randomization method. Clinical and laboratory examinations were evaluated before and after treatment. The concentration of INF-gamma was rather low in study group in comparison with control group before the beginning of the treatment, that indicates insufficient stimulation of T-lymphocytes in children with recurrent infection. INF-gamma lever significantly increased after treatment (Statistically significantly P<0.05) in study group in comparison with control group. Neopterin level unlike INF-gamma in study group was higher than in the control group, before and after treatment. This fact can be explained that neopterin as a slowly acting biologically active substance remains high during the presence of recurrent infections. Ribomunyl treatment significantly increased the level of neopterin. The efficacy of the product is primarily confirmed by significant reductions in the number of recurrent infections episodes and the use of antibacterials. Combined immunostimulating effect of Ribomunyl makes it possible to use Ribomunyl to create a longterm postvaccinal protection of the child.

Biomarkers↗

PubMed2004

Vitamin E and respiratory tract infections in elderly nursing home residents: a randomized controlled trial.

CONTEXT: Respiratory tract infections are prevalent in elderly individuals, resulting in increased morbidity, mortality, and use of health care services. Vitamin E supplementation has been shown to improve immune response in elderly persons. However, the clinical importance of these findings has not been determined. OBJECTIVE: To determine the effect of 1 year of vitamin E supplementation on respiratory tract infections in elderly nursing home residents. DESIGN, SETTING, AND PARTICIPANTS: A randomized, double-blind, placebo-controlled trial was conducted from April 1998 to August 2001 at 33 long-term care facilities in the Boston, Mass, area. A total of 617 persons aged at least 65 years and who met the study's eligibility criteria were enrolled; 451 (73%) completed the study. INTERVENTION: Vitamin E (200 IU) or placebo capsule administered daily; all participants received a capsule containing half the recommended daily allowance of essential vitamins and minerals. MAIN OUTCOME MEASURES: Incidence of respiratory tract infections, number of persons and number of days with respiratory tract infections (upper and lower), and number of new antibiotic prescriptions for respiratory tract infections among all participants randomized and those who completed the study. RESULTS: Vitamin E had no significant effect on incidence or number of days with infection for all, upper, or lower respiratory tract infections. However, fewer participants receiving vitamin E acquired 1 or more respiratory tract infections (60% vs 68%; risk ratio [RR], 0.88; 95% confidence interval [CI], 0.76-1.00; P =.048 for all participants; and 65% vs 74%; RR, 0.88; 95% CI, 0.75-0.99; P =.04 for completing participants), or upper respiratory tract infections (44% vs 52%; RR, 0.84; 95% CI, 0.69-1.00; P =.05 for all participants; and 50% vs 62%; RR, 0.81; 95% CI, 0.66-0.96; P =.01 for completing participants). When common colds were analyzed in a post hoc subgroup analysis, the vitamin E group had a lower incidence of common cold (0.67 vs 0.81 per person-year; RR, 0.83; 95% CI, 0.68-1.01; P =.06 for all participants; and 0.66 vs 0.83 per person-year; RR, 0.80; 95% CI, 0.64-0.98; P =.04 for completing participants) and fewer participants in the vitamin E group acquired 1 or more colds (40% vs 48%; RR, 0.83; 95% CI, 0.67-1.00; P =.05 for all participants; and 46% vs 57%; RR, 0.80; 95% CI, 0.64-0.96; P =.02 for completing participants). Vitamin E had no significant effect on antibiotic use. CONCLUSIONS: Supplementation with 200 IU per day of vitamin E did not have a statistically significant effect on lower respiratory tract infections in elderly nursing home residents. However, we observed a protective effect of vitamin E supplementation on upper respiratory tract infections, particularly the common cold, that merits further investigation.

Aged↗

PubMedDate not supplied

Mycoplasma hominis: a review of its role as a respiratory tract pathogen of humans.

Mycoplasma hominis seldom colonizes the human respiratory tract and only rarely causes acute respiratory infection. It can be recovered from the respiratory secretions of 1-3% of healthy persons and of less than or equal to 8% of persons with chronic respiratory disease, but it has not been implicated definitely in the etiology of this disease or in the exacerbations that characterize its course. M. hominis has been isolated from less than or equal to 6% of persons with acute pharyngitis or acute upper respiratory tract illnesses and can induce exudative pharyngitis in susceptible volunteers when administered intranasally and oropharyngeally. Colonization of the respiratory tract by M. hominis occurs in approximately 15% of persons who engage in oral-genital sexual practices, but colonization alone is not necessarily associated with sore throat or other upper respiratory diseases. Although M. hominis has been recovered from adults with pneumonia more often than from controls, a pathogenic role in pneumonia of adults has not been established. Under special conditions, e.g., neonatal pneumonia, M. hominis appears to be pathogenic for the lower respiratory tract. Thus M. hominis probably is only an occasional respiratory pathogen in the adult and a rare "opportunistic" pathogen of the respiratory tract of the neonate.

Adult↗