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[Viral infections in hospitalized children affected by acute lower respiratory tract disease]

OBJECTIVE: To evaluate the frequency of the main respiratory viruses in hospitalized children affected by acute lower respiratory tract disease at a university hospital. METHODS: This is a prospective trial that included two cohorts of hospitalized children in the period from April to July 1996. The groups were selected according to the presence of lower respiratory tract disease on admission: Group A- with acute disease (history of less than 7 days) and B- without present or recent respiratory disease. The parameters for defining lower respiratory tract disease included physical and/or radiological pulmonary changes. Clinical and radiological criteria were established for the classification of lower respiratory tract diseases in group A. Nasopharyngeal swab was collected from all children on admission for viral detection by cellular cultures and direct immunofluorescence. RESULTS: 201 cases were selected, 126 in group A and 75 in group B. Viruses were identified in 71 children from groupA(56.4%) and only in 3 from group B (4.0%). The predominant agent in group A was respiratory syncytial virus, identified in 66 cases; adenovirus (4) and influenza (1) were detected in other patients. In group B two patients with respiratory syncytial virus and one with adenovirus were identified. The patients from group A affected by respiratory syncytial virus were younger (median age 3 months versus 13 months) and more wheezy on physical examination (78.7%) than the other patients of the group (33.3%). This virus was associated to most of the bronchiolitis cases (84%) and to half of the pneumonia cases (46.4%). CONCLUSION: The authors found a significant presence of viruses in the majority of children hospitalized with acute lower respiratory tract disease. The respiratory syncytial virus was the predominant agent identified. These results are similar to others previously reported both in developed and some developing countries. The authors emphasize that the present study evaluated only partially the possibility of simultaneous infection by other pathogens and that the present protocol was conducted during the season with the highest incidence of respiratory syncytial virus.

Journal Article↗

Diagnostic value of the Binax NOW assay for identifying a pneumococcal etiology in patients with respiratory tract infection.

BACKGROUND AND PURPOSE: Streptococcus pneumoniae is a common pathogen in respiratory tract infections which is usually underestimated with conventional tests, largely due to the fragility of the bacteria. This study assessed the diagnostic value of a rapid test (Binax NOW) for the detection of the pneumococcal antigen in urine. METHODS: Unconcentrated urine samples from 1243 adults and 91 children hospitalized with respiratory tract infections were tested. RESULTS: In all adults with respiratory tract infections, the diagnostic results were as follows: sensitivity, 29 (60%) of 48; specificity, 748 (92.2%) of 811; negative predictive value, 748 (97.5%) of 767; false-positive rate, 63 (68%) of 92. The diagnostic results were similar in adults with lower respiratory tract infections: sensitivity, 21 (64%) of 33; specificity, 658 (92.2%) of 714; negative predictive value, 658 (98.2%) of 670; false-positive rate, 56 (73%) of 77. In children with respiratory tract infections, the diagnostic results were: sensitivity, 4 of 4; specificity 18 (64%) of 28; negative predictive value, 18 of 18; false-positive rate, 10 of 14. The low specificity of the test in children may be due to frequent pneumococcal nasopharyngeal colonization. CONCLUSIONS: High negative predictive values and high false-positive rates were found in both adults and children, indicating that a negative result may be more useful than a positive one in clinical practice. The high specificity of this test in adults indicates its potential value in the choice of initial antibiotic treatment by eliminating pneumococcal infection as a likely cause of respiratory tract infection in a proportion of patients.

Adult↗

Multiple roles for Bordetella lipopolysaccharide molecules during respiratory tract infection.

Bordetella pertussis, Bordetella parapertussis, and Bordetella bronchiseptica are closely related subspecies that cause respiratory tract infections in humans and other mammals and express many similar virulence factors. Their lipopolysaccharide (LPS) molecules differ, containing either a complex trisaccharide (B. pertussis), a trisaccharide plus an O-antigen-like repeat (B. bronchiseptica), or an altered trisaccharide plus an O-antigen-like repeat (B. parapertussis). Deletion of the wlb locus results in the loss of membrane-distal polysaccharide domains in the three subspecies of bordetellae, leaving LPS molecules consisting of lipid A and core oligosaccharide. We have used wlb deletion (Deltawlb) mutants to investigate the roles of distal LPS structures in respiratory tract infection by bordetellae. Each mutant was defective compared to its parent strain in colonization of the respiratory tracts of BALB/c mice, but the location in the respiratory tract and the time point at which defects were observed differed significantly. Although the Deltawlb mutants were much more sensitive to complement-mediated killing in vitro, they displayed similar defects in respiratory tract colonization in C5(-/-) mice compared with wild-type (wt) mice, indicating that increased sensitivity to complement-mediated lysis is not sufficient to explain the in vivo defects. B. pertussis and B. parapertussis Deltawlb mutants were also defective compared to wt strains in colonization of SCID-beige mice, indicating that the defects were not limited to interactions with adaptive immunity. Interestingly, the B. bronchiseptica Deltawlb strain was defective, compared to the wt strain, in colonization of the respiratory tracts of BALB/c mice beginning 1 week postinoculation but did not differ from the wt strain in its ability to colonize the respiratory tracts of B-cell- and T-cell-deficient mice, suggesting that wlb-dependent LPS modifications in B. bronchiseptica modulate interactions with adaptive immunity. These data show that biosynthesis of a full-length LPS molecule by these three bordetellae is essential for the expression of full virulence for mice. In addition, the data indicate that the different distal structures modifying the LPS molecules on these three closely related subspecies serve different purposes in respiratory tract infection, highlighting the diversity of functions attributable to LPS of gram-negative bacteria.

Animals↗

Virulence of capsulated and noncapsulated isolates of Pasteurella multocida and their adherence to porcine respiratory tract cells and mucus.

The virulence and the adherence to porcine respiratory tract cells and mucus of three toxigenic, capsular type D Pasteurella multocida isolates and their noncapsulated variants were evaluated in the present study. Loss of capsule by P. multocida, verified by transmission electron microscopy after polycationic ferritin labeling, was associated with a massive reduction in virulence of the organisms in mice. Specific-pathogen-free piglets inoculated intranasally with one of the capsulated isolates or its noncapsulated variant developed turbinate lesions characterized by bone resorption and by an inflammation of the mucosa associated with hyperplasia and squamous metaplasia of the epithelium. Infection with the capsulated isolate led to more severe lesions and atrophy of turbinates. The interactions of these P. multocida isolates with porcine respiratory tract cells and mucus were studied in vitro. The presence of capsule resulted in a decrease in binding of respiratory tract mucus were studied in vitro. The presence of capsule resulted in a decrease in binding of respiratory tract mucus to P. multocida isolates as determined by a dot blot assay. The presence of capsule also resulted in a significant decrease in adherence to porcine tracheal rings maintained in culture. The capsule seemed to mask outer membrane components which are involved in adherence. One of these components might be lipopolysaccharide since purified lipopolysaccharide bound respiratory tract mucus and blocked adherence of this microorganism to porcine tracheal rings. Our data indicate that capsular material does not seem to be involved in adherence of P. multocida to respiratory tract cells and mucus, but capsulated isolates are more virulent in mice and also in piglets.

Animals↗

New approaches to Pseudomonas aeruginosa lower respiratory tract infections.

Since 1973, the occurrence of respiratory tract infections due to P. aeruginosa has increased associated with the development of broad-spectrum penicillins. A clinical entity, diffuse panbronchiolitis (DPB) is a representative disease of chronic P. aeruginosa infections in Japan. In this paper, recent advances of research on pathogenesis and treatments of chronic P. aeruginosa lower respiratory tract infections in our department are reported. We examined sputum from patients with chronic P. aeruginosa infections under the electron microscope. Mucoid type of microcolonies were observed with fibrous matrix of exopolysaccharide. Neutrophils were found to be partially surrounding the microcolony in an attempt to defense. Debris was formed mainly by the destruction of the neutrophils. Most neutrophils were found full of phagocytized debris. These data support that instead of phagocytizing bacteria, neutrophils phagocytized debris and bacteria were not completely eradicated. This might be a factor in the pathogenesis of persistent colonization of P. aeruginosa. In the airways of patients with chronic airway diseases (CAD), neutrophils enhance the recruitment of more neutrophils through the production of neutrophil chemotactic factors such as interleukin-8 (IL-8) and LTB4, perpetuating a cycle of inflammation in the lung. We demonstrated increased levels of IL-8, a chemotactic cytokine, in bronchoalveolar lavage (BAL) fluid from patients with CAD associated with P. aeruginosa infections. We also documented a significant correlation between neutrophil numbers and IL-8 levels or IL-1 beta levels or neutrophil elastase levels in BAL fluids from patients with CAD. By immunohistochemical studies and in vitro data, three major sources of IL-8 in the airways of CAD patients were found to be alveolar macrophages, bronchial epithelial cells, and migrated neutrophils. In Japan, the clinical effectiveness of oral erythromycin (EM) for CAD, including DPB seems to be established, but its pharmacological mechanism remains unclear. In addition, we found a marked decrease of IL-8 levels in BAL fluid from two patients with CAD after treatment with EM. Therefore, we postulated that EM inhibited IL-8 production by stimulated respiratory cells. EM and Roxythromycin, suppressed IL-8 production in Pseudomonas-stimulated neutrophils in a dose-dependent manner. 1 alpha, 25-dihydroxy vitamin D3 also inhibited neutrophil-derived IL-8. Our data encourage the development of new anti-IL-8 agents against persistent P. aeruginosa lower respiratory tract infections.

Anti-Bacterial Agents↗

Ribavirin for respiratory syncytial virus infection of the lower respiratory tract in infants and young children.

BACKGROUND: Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract infection in infants and is responsible for 100,000 hospitalizations annually. Ribavirin is approved for treatment of these infections, but its use is controversial because of questions about its efficacy, concerns about occupational exposure, and its high cost. OBJECTIVES: The objective of this review is to assess the efficacy of aerosolized ribavirin for infants and children with lower respiratory tract infection due to RSV. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1, 2004), MEDLINE (January 1975 to January week 3, 2004) and EMBASE (January 1990 to December 2003). We scanned reference lists of articles and contacted experts in the field. SELECTION CRITERIA: Randomized trials comparing ribavirin with placebo in infants and children with RSV infection and lower respiratory tract infection. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial quality. Unpublished data were requested from authors when necessary. MAIN RESULTS: Twelve trials were included. All trials enrolled infants below the age of six months. In four trials with 158 patients, mortality with ribavirin was 5.8% compared with 9.7% with placebo (odds ratio (OR) 0.58; 95% confidence interval (CI) 0.18 to 1.85). In three trials with 116 patients the probability of respiratory deterioration with ribavirin was 7.1% compared with 18.3% with placebo (OR 0.37; 95% CI 0.12 to 1.18). In three studies with 104 ventilated patients, the weighted mean difference in days of hospitalization was 1.9 fewer days with ribavirin (95% CI -4.6 to +0.9) and the weighted mean difference in days of ventilation was 1.8 fewer days with ribavirin (95% CI -3.4 to -0.2). No statistically significant differences in long-term pulmonary function or in incidence of recurrent wheezing following RSV infection were associated with the use of ribavirin. REVIEWERS' CONCLUSIONS: Trials of ribavirin for RSV lack sufficient power to provide reliable estimates of the effects. The cumulative results of three small trials show that ribavirin may reduce the duration of mechanical ventilation and may reduce days of hospitalization. In addition, use of ribavirin may be associated with a decrease in the long-term incidence of recurrent wheezing following RSV disease. A large randomized controlled trial of ribavirin for ventilated and other high-risk patients is indicated.

Antiviral Agents↗

The Tucson Children's Respiratory Study. II. Lower respiratory tract illness in the first year of life.

Lower respiratory tract illnesses occurring during the first year of life in 1,179 healthy infants enrolled in the Children's Respiratory Study, Tucson, Arizona, are described. The children, who use the pediatricians of a health maintenance organization, were enrolled into the study between May 1980 and January 1984. Data were collected on signs, symptoms, and diagnosis for each illness; nasopharyngeal and throat swabs were collected at the acute visit for viral, chlamydial, and mycoplasmal cultures. The cumulative incidence of illness in the first year of life was 32.88 per 100 children. Of the 348 initial lower respiratory tract illnesses occurring in these infants, 60% were diagnosed as bronchiolitis. At least one infecting agent was identified in 66% of the specimens collected at the time of the first illness. Respiratory syncytial virus was the most common isolate; 12 other agents were also identified. There was a strong (p less than 0.0001) relation between agent identified, symptoms reported, and diagnosis; bronchiolitis was predominantly associated with respiratory syncytial virus and croup with parainfluenza viruses. Sex and ethnicity were unrelated to illness experience or to characteristics of the first illness. Lower respiratory tract illness occurrence in the Children's Respiratory Study appears to be similar to patterns observed elsewhere, suggesting that diagnoses (and infecting agents) have changed little over the past decades.

Humans↗

Resistance pattern of bacteria isolated from acute respiratory tract infection (ARI) cases.

Out of 350 acute respiratory tract infection (ARI) patients 110 (31.4%) were positive on culture. Among then (35.5%) yielded from upper respiratory tract infection (URI) and 64.5% yielded from lower respiratory tract infection (LRI). Predominant bacterial isolates from URI were Staph aureus (12.4%) and Strepto. pyogen (9.8%) whereas predominant agent from LRI were Strepto. pneumoniae (14.7%) and Haemophilus influenzae (8.6%). Capsular typing by polymerase chain reaction (PCR) and type specific antisera revealed that 64.7% of the isolates were type-b and rest were non-b. The most frequent resistance pattern of H. influenzae was found resistant to penicillin-ampicillin (64.7%) followed by SMX-TMP (14.7%) and tetracycline (5.9%). Among penicillin-ampicillin resistant strains, 81.8% were beta lectamase positive and 18.2% were beta lectamase negative. Among beta lectamase positive strains 66.7% were capsular type-b and 33.3% were non-b, had MICS < or = 8 microgram/ml. and < or = 4 microgram/ml. respectively. 5.9% strains of Strepto. pneumoniae was found resistant to SMX-TMP, 5.9% to penicillin-ampicillin and 2.9% to cephalexin. Common resistance pattern of Staph aureus was penicillin-ampicillin (60%), SMX-TMP (37.2%) and tetracycline-erythromycine-cephalexin (11.4%). Strepto. pyogen was found resistant to tetracycline in 12.2% cases and to SMX-TMP in 8.3% cases.

Acute Disease↗

Risk factors of wheeze and allergy after lower respiratory tract infections during early childhood.

Lower respiratory tract infections (LRIs) during early childhood can lead to bronchial hyperreactivity or recurrent obstructive bronchitis. The role of LRIs in the pathogenesis of allergic diseases such as allergic rhinoconjunctivitis, atopic eczema, and bronchial asthma is less clear. The aim of this retrospective study was to determine the incidence of subsequent wheezing and atopy, and the known risk factors for allergic sensitization in 74 children hospitalized for acute LRIs of various etiologies from January 1994 through December 1994. Results showed that there are no differences in outcomes between patients with respiratory syncytial virus LRI, Chlamydia pneumoniae LRI, and LRIs caused by other agents. Although lower respiratory tract illnesses, especially those caused by respiratory syncytial virus during infancy, were associated with an increased risk of subsequent wheezing during early childhood, wheezing tended to disappear with increasing age in many children. This study also found recurrent episodes of wheezing during the first 5 years of life, and symptoms suggestive of allergic rhinoconjunctivitis were the only factors predictive of subsequent diagnosis of asthma for children who had LRIs during early childhood. In conclusion, this study suggests that prevention of recurrent wheezing LRIs and good control of allergic rhinoconjunctivitis is critical for preventing subsequent development of bronchial asthma.

Asthma↗

Health-related quality of life of adults with upper respiratory tract infections.

OBJECTIVE: To determine the impact that upper respiratory tract infections have on patients' physical, social, and emotional functioning, we measured the health-related quality of life (HRQL) of adults with upper respiratory tract infections. SETTING: Acute care clinic from November 2001 to February 2002. DESIGN: Prospectively administered survey. To measure HRQL, we used the Acute Form of the Short Form-36, version 2 (SF-36). For all 8 SF-36 subscales, we used norm-based scoring, in which the general U.S. population has a mean of 50. PATIENTS: Adults who had symptoms for fewer than 30 days completed the SF-36; and were diagnosed with nonspecific upper respiratory infection, viral syndrome, otitis media, sinusitis, nonstreptococcal pharyngitis, streptococcal pharyngitis, or acute bronchitis. MEASUREMENTS AND MAIN RESULTS: The sample of 318 patients was 63% female, 81% white, and had a mean age of 35 years. The primary diagnoses were nonspecific upper respiratory infection (42%), acute bronchitis (16%), sinusitis (12%), viral syndrome (9%), nonstreptococcal pharyngitis (8%), otitis media (7%), and streptococcal pharyngitis (6%). Patients had a mean general health subscale score of 50.9, which is not significantly different from the mean population value of 50 (P =.09). However, there were significant decrements in the remaining 7 subscales of the SF-36: physical functioning (45.5), role-physical (38.5), bodily pain (42.6), vitality (40.8), social functioning (37.8), role-emotional (46.8), and mental health (46.8; P <.0001 for all 7 subscales compared with normative values). Results were similar for the subset of patients with no comorbid illnesses (P <.001 for the same 7 subscales) and patients diagnosed with nonspecific upper respiratory infection (P <.001 for the same 7 subscales). These decrements were similar in magnitude, but somewhat different in subscale pattern, to those of adults with chronic lung disease, osteoarthritis, and depression. CONCLUSIONS: Physicians should remember that adults who seek care for upper respiratory tract infections have measurable, significant decrements in HRQL. For researchers, HRQL is an attractive, potential measure of outcome in future trials of established and novel therapies for upper respiratory tract infections.

Adolescent↗

[Diagnosis and treatment in general practice of lower respiratory tract infections in adults].

Lower respiratory tract infections are common in the community. It might be difficult to differentiate between acute bronchitis, exacerbation of chronic obstructive pulmonary disease, and pneumonia. There is no satisfactory way of defining pneumonia by clinical criteria alone. Measurement of C-reactive protein is useful, but the specificity of the test is low, and must be carefully evaluated in comparison with the duration of illness and the clinical picture. The antibiotic management of lower respiratory tract infections must suppress Streptococcus pneumoniae. We therefore recommend that the first drug of choice should be penicillin V.

Adult↗

Appropriate management of lower respiratory tract infections in primary care.

Respiratory tract symptoms are one of the major reasons for consultations with general practitioners. Most patients present because of symptoms that distress them or their family, or for reassurance that the symptoms do not represent something serious, or in order to receive medication. Many patients believe that their symptoms are due to an infection and expect to receive an antibiotic. These expectations influence the doctor's prescribing such that many patients will receive antibiotics even if the general practitioner considers these not to be required. This article describes the principles of rational antibiotic prescribing for lower respiratory tract infections in primary care, including disorders such as acute bronchitis, acute exacerbations of chronic obstructive pulmonary disease (COPD) and community-acquired pneumonia.

Journal Article↗

Coronavirus isolation from nasal swab samples in cattle with signs of respiratory tract disease after shipping.

OBJECTIVE: To monitor the prevailing viral respiratory tract infections in cattle after transportation to feedlots. ANIMALS: 100 cattle with signs of respiratory tract disease on arrival at 2 feedlots. PROCEDURES: Nasal swab samples were obtained from each animal and were used for inoculation of defined cell culture systems that detected bovine viruses known to cause respiratory tract infections, as well as viruses previously not recognized as respiratory pathogens for cattle. RESULTS: Bovine respiratory coronaviruses were isolated from 38 of the 100 cattle, including 6 of 50 cattle from California, 22 of 31 cattle from Oklahoma, 6 of 11 cattle from Texas, and 4 of 8 cattle of unknown origin. Parainfluenza 3 viruses also were isolated from 5 California cattle, but other bovine viruses were not detected. CLINICAL IMPLICATIONS: The high rate of coronavirus isolations from feedlot cattle with signs of respiratory tract disease implied wide distribution and high susceptibility among cattle to this infection, which had not been detected by use of viral isolation systems in previous etiologic evaluations of feedlot cattle affected with bovine respiratory disease complex.

Animals↗

Development of the airway intraepithelial dendritic cell network in the rat from class II major histocompatibility (Ia)-negative precursors: differential regulation of Ia expression at different levels of the respiratory tract.

The relative inefficiency of respiratory mucosal immune function during infancy is generally attributed to the immaturity of the neonatal T cell system. However, immune competence in the adult lung has recently been shown to be closely linked to the functional capacity of local networks of intraepithelial dendritic cells (DC). This study examines the density and distribution of these DC throughout the neonatal respiratory tract in rats, focusing particularly on microenvironmental regulation of their class II major histocompatibility complex (MHC) (Ia) expression. In animals housed under dust-controlled conditions, airway epithelial and alveolar Ia+ DC detectable by immunostaining with the monoclonal antibody (mAb) Ox6 are usually not seen until day 2-3 after birth, and adult-equivalent staining patterns are not observed until after weaning. In contrast, the mAb Ox62 detects large numbers of DC in fetal, infant, and adult rat airway epithelium. Costaining of these Ox62+ DC with Ox6 is rare in the neonate and increases progressively throughout infancy, and by weaning Ia+ DC comprised, on average, 65% of the overall intraepithelial DC population. In infant rats, Ia+ DC are observed first at the base of the nasal turbinates, sites of maximum exposure to inhaled particulates, suggesting that their maturation is driven in part by inflammatory stimuli. Consistent with this suggestion, densitometric analysis of Ia staining intensity of individual DC demonstrates that by 2-3 d after birth, Ia expression by nasal epithelial DC was comparable with that of Iahigh epidermal Langerhans cells in adjacent facial skin, at a time when expression by tracheal epithelial DC was 7-10-fold lower. Additionally, the rate of postnatal appearance of Iahigh DC in the airway epithelium was increased by administration of interferon gamma, and decreased by exposure of infant rats to aerosolized steroid. These findings collectively suggest that Ia expression by neonatal respiratory tract DC is locally controlled and can be upregulated by mediators that are produced within the lung and airway epithelium in response to inhalation of proinflammatory stimuli. It was also noted that Ialow neonatal airway DC expressed adult equivalent levels of class I MHC, which suggests differences in capacity to prime for CD8(+)-dependent versus CD4(+)-dependent immunity to inhaled pathogens, during the early postnatal period.

Androstadienes↗

Viral etiology and epidemiology of acute lower respiratory tract infections in Korean children.

Viral etiologic agents of acute lower respiratory tract infections were studied from November, 1990, through April, 1994, in Korean children. From 712 children who visited or were admitted to Seoul National University Children's Hospital because of acute lower respiratory tract infections, 804 nasal aspirates were collected; viral agents were detected by virus isolation and virus antigen was detected by indirect immunofluorescent staining. One or more viral agents were identified in 369 (45.9%) cases; of which 3.3% were mixed infections. The pathogens identified were respiratory syncytial virus (27.2%), parainfluenza virus type 3 (7.8%), influenza A virus (3.9%), adenovirus (3.9%), parainfluenza virus type 1 (1.7%), influenza B virus (1.4%), parainfluenza virus type 2 (0.5%), measles virus (0.1%) and others (0.9%). The clinical patterns of viral lower respiratory tract included pneumonia (56.6%), bronchiolitis (35.2%), croup (6.5%) and tracheo-bronchitis (1.6%). Infections with respiratory syncytial virus, parainfluenza virus types 1 and 3 and influenza A and B virus occurred in epidemics, whereas adenovirus was isolated sporadically throughout the study period. The data expand our understanding of the epidemiology of acute viral lower respiratory tract infections in Korean children and may be helpful to the clinicians and researchers interested in the control of viral respiratory tract infections.

Acute Disease↗

The effect of oropharyngeal decontamination using topical nonabsorbable antibiotics on the incidence of nosocomial respiratory tract infections in multiple trauma patients.

The incidence of respiratory tract infections was determined in 59 multiple trauma patients requiring prolonged intensive care (greater than 5 days) and receiving no antibiotic prophylaxis. Early pneumonia (less than 48 hr) with S. aureus, S. pneumoniae, and/or H. influenzae was found in 44% of patients. Secondary colonization of the oropharynx and respiratory tract with ICU-associated Gram-negative bacilli followed by pneumonia occurred in 12 patients (20%). The overall incidence of respiratory tract infections was 59%. In a prospective open trial three prophylactic antibiotic regimens were compared: 17 patients were treated with intestinal decontamination using nonabsorbable antibiotics (polymyxin E 400 mg, tobramycin 320 mg, amphotericin B 2,000 mg/day). No difference in infection rate was found. Twenty-five patients were treated with intestinal and oropharyngeal decontamination using an ointment containing 2% of the same antibiotics. Secondary colonization and infection of the respiratory tract with Gram-negative bacilli was significantly reduced (p less than 0.001). The incidence of early (Gram-positive) infections, however, was unchanged. Another group of 63 patients was treated with systemic antibiotic prophylaxis during the first days in combination with oropharyngeal and intestinal decontamination. The incidence of early pneumonia was significantly reduced (p less than 0.001). Five patients (8%) developed an infection. Superinfections were not observed.

Administration, Topical↗

Dietary selenium- and benzo[a]pyrene-induced respiratory tract tumours in hamsters.

The modifying effect of selenium as sodium selenite on chemically induced respiratory tract tumours was tested in Syrian golden hamsters. Groups of 40 hamsters per sex (controls 60 per sex) were fed the following semisynthetic diets: control diet (0.1 p.p.m. Se, low fat); high-Se diet (5 p.p.m.); high-fat diet (20% sunflower oil); or high-Se + high-fat diet. After an adaptation period of 30 days on the diets, respiratory tract tumours were induced by intratracheal instillation of benzo[a]pyrene attached to ferric oxide. The experimental period was 429 days for males and 374 days for females. Respiratory tract tumours included mainly epidermoid papillomas, epidermoid carcinomas and combined epidermoid and adenocarcinomas. Selenium included either in a low-fat or high-fat diet did not influence the tumour response in the respiratory tract or in other organs. Neither was there a correlation between the serum or liver Se levels in the presence of respiratory tract tumours. The tumour response in the respiratory tract and also in other organs was slightly respiratory tract and also in other organs was slightly enhanced by dietary fat.

Animals↗