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PubMed2007

Application of morphological and physiological parameters representative of a Brazilian population sample in the respiratory tract model.

The human respiratory tract model (HRTM) adopted by ICRP in its Publication 66 accounts for the morphology and physiology of the respiratory tract. The characteristics of air drawn into the lungs and exhaled are greatly influenced by the morphology of the respiratory tract, which causes numerous changes in pressure, flow rate, direction and humidity as air moves into and out of the lungs. These characteristics are important to determine the fractional deposition. It is known that the morphology and physiology are influenced by environmental, occupational and economic conditions. The ICRP recommends, for a reliable evaluation of the regional deposition, the use of parameters from a local population wherever such information is available. The main purpose of this study is to verify the influence of using the morphology and physiology parameters representative of a sample of the Brazilian population on the deposition model of the ICRP Publication 66 model.

Algorithms↗
PubMed2003

[Respiratory tract viruses].

The respiratory tract is the site of entrance of many viruses. However, not all of them cause symptomatic respiratory infections. In the past the clinical significance of some viruses was underestimated. Viruses leading to population-wide epidemics like influenzavirus or to nosocomial outbreaks like respiratory syncytial virus or SARS-associated coronavirus have a great impact on public health and the respective preventive measures are of paramount importance. The advent of new diagnostic tools led to discoveries and additional information about some "banal" viruses causing severe diseases in special hosts such as infants and immunosuppressed patients. In addition new viral pathogens were discovered and found to cause respiratory infections, metapneumovirus and SARS-associated coronavirus being the most important ones.

Antibodies, Viral↗
PubMed1982

Respiratory tract immune response to microbial pathogens.

Effective resistance to respiratory tract infection depends principally on specific immunity on mucosal surfaces of the upper or lower respiratory tract. Respiratory tract immune response comprises antibody and cell-mediated systems and may be induced most readily by surface presentation of replicating agents but can result from parenteral or local presentation of highly immunogenic antigens. Upper and lower respiratory tract systems differ in immunologic competence, with the lungs having a greater inventory of protective mechanisms than the trachea or nose. Several effective vaccines have been developed for prevention or modification of respiratory tract diseases.

Animals↗
PubMed1997

Prevalence of Chlamydia pneumoniae in healthy children and in children with respiratory tract infections.

BACKGROUND: Chlamydia pneumoniae causes respiratory tract infections in adults, but little is known about its significance for acute or persistent respiratory tract infections in children. METHODS: We studied the prevalence of C. pneumoniae by polymerase chain reaction in children younger than the age of 11: 85 consecutive children with respiratory tract infections; and 93 children presumed to be healthy. Throat swabs for PCR analysis were taken from all children, and serology was done for 54 of the 85 sick children and from all but one of the presumed healthy children positive for C. pneumoniae by PCR. RESULTS: PCR was positive in 38 (45%) of the sick children and in 5 (5.7%) of the healthy children. All but 2 of 19 sick children with serologic findings suggesting recent or ongoing infection with C. pneumoniae were positive by PCR. Most children positive for C. pneumoniae by PCR had upper respiratory tract infections. Four children had recurrent respiratory tract infections and otitis media with effusion treated by tubal insertion. CONCLUSION: The findings suggest that C. pneumoniae is common among children with respiratory tract infections.

Age Factors↗
PubMed1990

Antimicrobial drugs for respiratory tract infections.

The respiratory tract of small animals is exposed to a large number of potential pathogens. If endogenous defense mechanisms are not able to remove the invading microorganism, infection may result. The veterinarian must then determine if antimicrobial therapy is appropriate and, if so, which drug to use, at which dose, and for how long. This article discusses the therapeutic problems that arise when deciding on antimicrobial therapy in small animal respiratory disease.

Animals↗
PubMed2006

[Definition of low respiratory tract infections].

Lower respiratory tract infection is easily suggested on clinical signs (cough and sputum) associated with fever. To discriminate between pneumonia and acute bronchitis is crucial because of the mortality associated with pneumonia and of its specific management. Chest X-ray is a key exam for the diagnosis and should be performed on the basis of validated clinical signs that are however of weak diagnostic value. Clinical as well as radiological signs cannot be reliably used to identify the causative germ. Sputum examination, the search for pneumococcal and legionella urinary antigens are of good diagnostic value. An associated COPD may lead to an acute respiratory failure. Acute exacerbation of chronic bronchitis results from various causes but infection is involved in about 50% of the cases, mostly viral and most often due to a rhinovirus. Viral infection can be associated to bacterial infection and the most frequently isolated germs are Streptococcus pneumoniae, Haemophilus influenzae, and B. catarrhalis. Severity assessment relies on the value of basal FEV1 that is often non available. Therefore Afssaps suggests using a dyspnea index to assess exacerbation severity.

Adult↗
PubMed1998

Potential infectious disease complications of upper respiratory tract infections.

Upper respiratory tract infections (URTIs), particularly otitis media and sinusitis, are prevalent among children. With recurrent URTIs there is an increased likelihood of sequelae. Suppurative complications associated with URTIs, although rare, must be treated rapidly to prevent serious morbidity and mortality. Further, increase in antimicrobial resistance may be accompanied by an increased risk for complications because infecting pathogens may be more difficult to eradicate.

Child↗
PubMed1990

Upper respiratory tract infections.

Upper respiratory tract infections are among the most common acute infections in humans. This review discusses the clinically important aspects of the epidemiology, etiology, clinical presentation, diagnosis, management, complications, and prevention of the common cold, pharyngitis, otitis media, and sinusitis. Most episodes of the common cold and pharyngitis are of viral origin, and curative therapy is not available. Streptococcal pharyngitis, acute otitis media, and sinusitis are secondary to bacterial infections, and antibiotic therapy is important.

Anti-Bacterial Agents↗
PubMed1995

Mechanisms of airway narrowing and hyperresponsiveness in viral respiratory tract infections.

Viral respiratory tract infections are associated with an acute increase in airway responsiveness in normal subjects and patients with asthma. Airway responsiveness is also increased at least transiently in animals during acute viral infections. In this article, we discuss possible mechanisms whereby viral infections can increase airway responsiveness, emphasizing the effects of viral-induced airway epithelial damage during acute lytic infection and the mechanical consequences of airway inflammation and edema, both internal and external to the smooth muscle layer. We also describe possible mechanisms by which acute lytic viral infections could induce chronic sequelae in atopic individuals and contribute to the development of persistence of asthma. Finally, results of recent studies from our laboratory that document adenoviral genome in lungs of patients with chronic obstructive pulmonary disease (COPD) and long-term persistence of respiratory syncytial viral genome and protein in an animal model are discussed in terms of the possible role of latent and persistent viral infections in the pathogenesis of asthma and COPD.

Animals↗
PubMed1991

The scope of lower respiratory tract infection.

Lower respiratory tract infections (LRTI) are commonly classified as either bronchitis or pneumonia, and these infections are associated with an extremely high morbidity in the community, as well as a high mortality in those patients that require hospitalisation. Therefore, such infections place a huge burden, both economically and as a user of health services, on the entire health care system. The antibiotic treatment of community-acquired pneumonia caused by gram-negative organisms or staphylococci is controversial, and these organisms may cause one-third of the cases of community-acquired pneumonia. Nosocomial pneumonia is caused even more often by gram-negative bacteria, and as such the development of rational and effective antibiotic therapy to cover these organisms is very important.

Anti-Bacterial Agents↗
PubMed1983

[Clinical evaluation of the efficacy of cefmetazole in respiratory tract infections of patients with underlying respiratory diseases].

Respiratory infections of 10 subjects with underlying respiratory diseases were treated with cefmetazole (CMZ) and its clinical effects were studied. Five subjects of them were respiratory tract infection, 3 subjects were pneumonia and 2 subjects were pneumonia followed by empyema. The underlying diseases were chronic pulmonary emphysema in 4 subjects, diffuse panbronchiolitis in 3, chronic bronchitis in 2 and bronchial asthma in 1. The doses of CMZ were 4 to 8 grams per day and the durations of administration ranged 3 to 39 days. The clinical effects were judged from the changes of fever, cough, amount of sputum, dyspnea, rale, chest X-ray, white blood cell counts, erythrocyte sedimentation rates, sputum culture and PaO2. The clinical effects of 6 subjects were evaluated as good, those of 3 were fair and that of 1 was poor. In 3 subjects H. influenzae in the sputum was eliminated and in 1 subject both H. aphrophilus and alpha-Streptococcus found in the pleural effusion were eliminated. In 1 subject Klebsiella in the sputum was eliminated and replaced by Enterobacter. No side effects were observed. We conclude that CMZ is considerably useful in the treatment of respiratory infections of the patients with underlying respiratory diseases.

Adult↗
PubMed2001

The management of upper respiratory tract infections.

Upper respiratory tract infections are the commonest reason for consultation in primary care. Group A beta-haemolytic Streptococcus (GABHS), the most important bacterial pathogen in this condition, can be cultured from about 30% of patients, more so in children than adults. Clinical features that are predictive of positive GABHS culture are absence of cough, fever, cervical adenopathy, tonsillar enlargement and tonsillar exudate. Use of a sore throat score can help in the detection of streptococcal throat infection. Symptomatic therapies which are useful include anticholinergic, antihistamine, decongestant, humified hot air and Vitamin C. Antibiotics are universally over-prescribed in this condition as a result of high patient expectation and faulty clinical decision making. Oral Penicillin V for 10 days is the drug of choice. Effective intervention to reduce inappropriate antibiotic prescription probably require a multifaceted approach targeted at both the patients and the prescribers.

Adult↗
PubMed1995

Intermittent treatment with inhaled steroids for deterioration of asthma due to upper respiratory tract infections.

Upper respiratory tract infection (URTI) is a common cause of deterioration of asthma in children. We investigated if inhaled steroids (budesonide), started early after URTI, could reduce asthma. Thirty-one children, 3-10 years of age, with deterioration during URTI participated. The study design was double-blind, crossover and placebo-controlled. Peak-expiratory flow (PEF) and symptom scores were recorded. Four treatment periods of 9 days, two with budesonide and two with placebo, were planned. Treatment was started at the first sign of URTI. Budesonide/placebo was given by Turbuhaler at 0.2 mg qid for 3 days, tid for 3 and bid for the last 3 days. Twenty-two children completed 67 periods. Eleven visited the emergency room, only three during budesonide therapy. Five received oral steroids and two where admitted to hospital, all receiving placebo. Symptom scores were not significantly lower during budesonide treatment. PEF, both morning and evening, was significantly higher during budesonide than placebo (p = 0.015 and p = 0.022). Inhaled budesonide can attenuate exacerbation of URTI-induced asthma.

Administration, Inhalation↗
PubMed2001

Elevated levels of myeloperoxidase, pro-inflammatory cytokines and chemokines in naturally acquired upper respiratory tract infections.

Upper respiratory tract infections (URTIs) are characterised by a neutrophilic mucosal infiltration. The purpose of this study was to investigate the time course of release of the cytokines/chemokines interleukins (IL) IL-1beta, IL-1ra, tumour necrosis factor-alpha (TNF-alpha), IL-6, IL-8, interferon-gamma (IFN-gamma) and monocyte chemotactic protein (MCP-1), soluble intercellular adhesion molecule-1 (sICAM-1), myeloperoxidase (MPO) and bradykinin in nasal secretions of patients with a naturally acquired URTI. A total of 117 healthy adult volunteers were recruited for baseline nasal lavages, 39 of whom developed URTI symptoms within 6 months and returned to our centre within 48 h. Lavages were performed daily during the symptomatic period and 3 weeks thereafter, with symptoms no longer present. Compared to baseline, significantly elevated concentrations of total protein, bradykinin, IL-1beta, TNF-alpha, IL-6, IL-8, MCP-1, IFN-gamma, MPO and sICAM-1 were detected in nasal lavage fluids of symptomatic patients, whereas IL-1ra remained unaltered. All studied variables reached baseline 3 weeks after the URTI. Naturally acquired URTI represent a limited, neutrophilic inflammatory reaction, orchestrated by the release of pro-inflammatory cytokines and chemokines.

Adult↗
PubMed2002

Clinical and economic implications of antimicrobial resistance for the management of community-acquired respiratory tract infections.

Lower respiratory tract infections (RTIs), particularly community-acquired pneumonia (CAP), account for over 50 million deaths annually worldwide. They place an extensive clinical and financial burden on healthcare authorities. Upper RTIs, usually mild and non-life threatening, also incur significant healthcare costs. The rising prevalence of resistance of the major causative agents of CAP (Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis) to beta-lactam antimicrobials and newer macrolides has necessitated new strategies for appropriate antimicrobial usage. A successful clinical outcome will depend on the patient, choice of drug, and the epidemiology and resistance of the pathogen. Treatment failure will result in increased costs, particularly if hospitalization is required. Pharmacokinetic and pharmacodynamic parameters are being used increasingly to predict maximally effective therapy and optimal bacterial eradication, thus limiting the development of resistance. Antimicrobial susceptibility criteria by MIC should be dictated by the type and location of the infection. Modifying the current MIC breakpoints for penicillin so that more pneumococcal pneumonia isolates are reported appropriately as being susceptible may lead to a decrease in the use of broad-spectrum antimicrobial therapy and its associated increased costs, in favour of more narrow-spectrum therapy. Targeting the pathogen with the most effective antimicrobial in an appropriately selected patient should optimize clinical and microbiological success and, consequently, maximize response rates and economic outcomes. In addition, research efforts need to concentrate on developing new agents with low propensity to select for or induce resistance.

Community-Acquired Infections↗
PubMedDate not supplied

Host-pathogen relationships in respiratory tract infections.

The respiratory tract is continuously exposed to inhaled particles. The mucous membrane and the mechanisms of sneezing, coughing, and mucociliary clearance are the first line of defense. For the bronchioli and alveoli, the phagocytic cells are the cornerstone of defense against invading microorganisms. Alveolar macrophages and polymorphonuclear leukocytes are responsible for phagocytosis. For optimal phagocytosis, antibodies and complement are needed; phagocytic cells possess receptors for the Fc fragment of the immunoglobulin (IgG) molecule and complement. Receptors for cytokines are also present. These cytokines are important for activating the alveolar macrophage and recruiting other phagocytic cells and lymphocytes to the site of infection. Alveolar macrophages also contain cytophilic antibodies, IgG molecules that are bound to the cell via the F(ab)2 fragments. These cytophilic antibodies can interfere with the process of phagocytosis. They can bind to bacteria containing an Fc receptor (eg, Staphylococcus aureus protein A) and therefore provide the alveolar macrophage with a means to bind and digest staphylococci. Pulmonary surfactant proteins enhance the uptake of bacteria and viruses by alveolar macrophages and viruses. Thus surfactant contributes to the defense mechanisms of the lung. Phagocytic cells can injure alveoli. During the process of phagocytosis, toxic oxygen species and enzymes, needed for killing bacteria, are produced. These toxic substances may leak out of the cell and damage the surrounding tissues. All these phenomena contribute to the processes of inflammation. The function of phagocytic cells is decreased in smokers and by certain air pollutants. Phagocytic cells are crucial for the elimination of microorganisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria↗
PubMed1993

Importance of beta-lactamase stability in treating today's respiratory tract infections.

In respiratory tract infections Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae and Klebsiella spp. are the most frequently encountered bacterial pathogens. Resistance of clinical S. pneumoniae isolates is known to be independent of beta-lactamase production, whereas resistance of the other species mentioned is due to beta-lactamase production. With respect to M. catarrhalis the first beta-lactamase-producing (bla+) isolate was detected in clinical specimens in 1976 and now, 70-90% of all clinical isolates are bla+. The enzymes BRO-1 and BRO-2 are transposon-mediated thus explaining their rapid spread; they hydrolyze penicillin compounds very rapidly and, to a lesser extent, the older cephalosporins. Resistance in clinical H. influenzae isolates is mainly due to the prevalence of the most widespread transposon-mediated beta-lactamase, TEM-1, which has a substrate profile resembling that of the BRO enzymes. Bla+ H. influenzae isolates make up to 6% of the total in Northern Europe, in Southern Europe up to 55% and in many African countries more than 80%. More than 95% of Klebsiella spp. isolates possess a chromosomally encoded penicillinase and to a varying extent a plasmid-mediated enzyme in addition. Recently, reports from several countries have pointed to the clinical relevance of 'extended-spectrum enzymes' derived by point mutation from the 'classical' TEM-1 or TEM-2 enzymes. These new enzymes (TEM-3 to TEM-21) exhibit a broadened substrate profile, inactivating even the oxyiminocephalosporins. The most stable compounds are ceftibuten and cefetamet. With respect to the future, these enzymes may spread between species due to their location on transposons.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria↗