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Biomedical subjects

M S Niederman

Publications and source records attributed to M S Niederman.

107 records · Page 6Linked to original sources
PubMed1986

Pneumonia in the elderly.

Pneumonia from bacterial and viral agents is the fourth leading cause of death in persons over age 65, accounting for 169.7 deaths per 100,000 persons per year. This high incidence of infection is the result of aging itself as well as age-related coexisting illnesses and their therapies. These factors combine to affect upper and lower respiratory tract host defenses adversely against invading pathogens. Gram-negative colonization of the oropharynx, followed by the spread of bacteria to the tracheobronchial tree, commonly precedes the development of pneumonia. Bacterial adherence is one important and modifiable pathogenetic factor that leads to colonization at both of these sites. Diagnosis of pneumonia in the elderly is often thwarted by difficulties in recognizing infection, as signs and symptoms differ from those observed in younger patients. Therapy is confounded by the frequent inability to obtain adequate culture material to establish a likely pathogen and by altered drug metabolism. In this instance epidemiologic data may be helpful in guiding therapy. Streptococcus pneumoniae is the most common pathogen in community patients, followed by Legionella pneumophila and enteric gram-negative bacilli. Hospitalized and institutionalized individuals are commonly infected with Klebsiella pneumoniae and other enteric gram-negative bacilli, and Legionella pneumophila and Streptococcus pneumoniae are also found. Because recognition of pneumonia may be difficult and therapy is fraught with problems, mortality is high in the elderly. Accordingly, serious attention must be paid to prevention. Prophylaxis includes the use of pneumococcal and influenza vaccines as well as careful attention to the patient's host defense status. Disease states leading to impairment of the immune system should be sought, and efforts should be made to improve host factors that assist the individual in removing invading pathogens.

Aged↗
PubMed1986

Bacterial adherence to respiratory tract cells. Relationships between in vivo and in vitro pH and bacterial attachment.

Alterations in in vitro pH have been shown to have a significant effect on the bacterial binding capacity of epithelial cells for certain organisms. We investigated the effect of in vivo pH and in vitro changes in pH on the adherence of Pseudomonas aeruginosa to buccal and tracheal cells of 19 chronic tracheostomy patients. In addition, airway pH was measured in 5 normal volunteers. Oropharyngeal and endobronchial pH were measured with a flexible electrode that could be passed through a bronchoscope under direct visualization. In vitro adherence of Pseudomonas to respiratory epithelial cells was determined at pH 6.5 and 7.2. Colonization status of the patients was determined by culture of oropharyngeal and tracheal secretions. The pH value of each site in the respiratory tract and its secretions were different in the tracheostomy patients (buccal pH 6.3; tracheal, 6.9; sputum, 7.5). No difference was noted in pH of the 2 sites in control subjects (buccal, 6.7; tracheal, 6.7). Changes in in vitro pH had a significant effect (p less than 0.004) on bacterial binding to epithelial cells from both sites. The pH had its greatest effect on tracheal cells of patients colonized with Pseudomonas. Increased in vitro binding of these organisms was noted at the more alkaline pH. The magnitude of the effect of in vitro pH alteration on bacterial binding correlated directly with the degree of binding. These results demonstrated that pH has a significant effect on in vitro Pseudomonas adherence and the effect is most marked on cells obtained from the lower respiratory tract of patients colonized with this organism.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Tension ball valve mucus plug in asthma.

This report describes a patient with status asthmaticus and respiratory failure in whom profound hypoxemia developed during mechanical ventilation. During the hypoxemic episode, breath sounds were absent over the left lung, and chest radiography revealed a hyperlucent left hemithorax with tension shift of the mediastinum to the right. The presence of lung markings in the left lung on radiography eliminated the possibility of tension pneumothorax and led to the diagnosis of tension mediastinal shift secondary to a ball valve obstruction by a central mucus plug. Bronchoscopic lung lavage removed the mucus plug, thereby correcting the hypoxemia. Recognition of this previously undescribed acute complication of mechanical ventilation in status asthmaticus is essential so that confusion with tension pneumothorax is avoided and appropriate therapy instituted.

Adult↗
PubMed1984

Demonstration of a free elastolytic metalloenzyme in human lung lavage fluid and its relationship to alpha 1-antiprotease.

Although the human alveolar macrophage in tissue culture can secrete an elastolytic metalloenzyme that is not inactivated by alpha 1-antiprotease (AAP), levels of this proteolytic activity and its relationship to AAP in human lung lavage fluid ( HLF ) are unknown from previous studies. Therefore, we measured elastolytic activity in concentrated (20- to 30-fold) HLF from 15 smokers and 10 nonsmokers and related results to measurements of AAP in these fluids. Activity (mean +/- SEM) against a C elastin substrate (expressed as nanograms of porcine pancreatic elastase equivalents per milligram of lavage fluid protein) in smokers, 18.9 +/- 6.7, significantly exceeded (p = 0.05) levels present in nonsmokers, 4.4 +/- 1.8. With the synthetic elastin-like chromophore substrate succinyl-trialanine-nitroanilide ( SLAPN ), activity in individual samples was reduced 79% by EDTA, a metalloproteinase inhibitor, whereas activity was reduced by only 29% in the presence of PMSF, a serine proteinase inhibitor. In addition, using a pooled sample of HLF and C elastin substrate, 80% of activity against the elastin substrate was eliminated by EDTA, whereas 51% was eliminated by PMSF. The activity measured with C elastin substrate correlated inversely with antigenic AAP (r = -0.05, p = 0.01), but no correlations were found between this activity and HLF cell number, cell viability, differential count, or subject smoking history. The detection of activity with C elastin in HLF , with primarily a metalloenzyme inhibitor profile, in the presence of antigenically detectable AAP, may have pathogenetic relevance for emphysema in humans.

Adult↗
PubMed1984

Respiratory infection complicating long-term tracheostomy. The implication of persistent gram-negative tracheobronchial colonization.

Colonization of the lower respiratory tract by enteric Gram-negative bacilli (EGNB) has been a frequent finding in patients with long-term tracheostomies; however, the association of hospitalization and certain features of serious illness with this phenomenon has not been clearly established. Because such factors can render the oropharynx more susceptible to EGNB colonization, we sought to discover whether they can also have this effect on the tracheobronchial tree and its microflora. Thus, we collected serial paired culture samples from these two mucosal sites in 15 subjects with long-term tracheostomies and examined patterns and rates of colonization and related these findings to clinical parameters. In 49 sets of cultures, we found that EGNB (especially Pseudomonas species) were present in significantly fewer upper-airway cultures (36.7 percent) than lower-airway cultures (75.5 percent) (p = 0.009). At the tracheobronchial site, seven subjects had persistent EGNB colonization, all with Pseudomonas species, while only one subject had this finding at the oropharyngeal site (p = 0.015). Patients with persistent tracheobronchial colonization were more ill than those without this finding. They were treated with higher doses of prednisone (p = 0.06), received antibiotics more often, and developed purulent tracheobronchitis more often (100 percent vs 25 percent) than patients without persistent colonization. In addition, in the month following the culture survey, four subjects developed pneumonia, and three of these had previous persistent tracheobronchial colonization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Nutritional status and bacterial binding in the lower respiratory tract in patients with chronic tracheostomy.

Patients with chronic tracheostomy often develop tracheobronchial colonization with enteric gram-negative bacilli, especially Pseudomonas aeruginosa, but pathogenic mechanisms are largely unknown. To examine this problem, we measured in-vitro bacterial adherence to airway epithelial cells from the tracheal surfaces of 15 patients with chronic tracheostomy and 18 healthy, noncolonized controls without tracheostomy. Patients with tracheostomy had more tracheal cell adherence (7.3 +/- 0.4 [SE] bacteria/cell) than controls (4.8 +/- 0.7 bacteria/cell; p = 0.008), but patients colonized by Pseudomonas species had even more binding (9.0 +/- 0.06 bacteria/cell) than those without this finding (5.8 +/- 0.8 bacteria/cell; p = 0.008). Differences between patients in lower airway cell binding of bacteria were largely related to a multifactorial assessment of patient nutritional status, the prognostic nutritional index (r = 0.67, p = 0.005). Thus, nutritional status may account in part for the common problem of tracheobronchial colonization with gram-negative bacteria in patients with chronic tracheostomy.

Adhesiveness↗
PubMed1983

Comparison of bacterial adherence to ciliated and squamous epithelial cells obtained from the human respiratory tract.

Previous in vitro studies have suggested that bacterial adherence to buccal squamous epithelial cells may be a mechanism involved in postoperative colonization of the oropharynx. However, the relationship between bacterial binding to oral epithelial and ciliated respiratory cells is unknown. To investigate bacterial binding to other cells in the human respiratory tract, we measured adherence of Pseudomonas seruginosa to ciliated cells (from nose and trachea) and compared this to squamous cells (from buccal mucosa), Cell samples were collected from 16 noncolonized individuals undergoing either elective surgery or volunteer bronchoscopy. Adherence (mean +/- SEM) to tracheal cells (4.6 +/- 0.8 bacteria per cell) and to nasal cells (4.7 +/- 0.6 bacteria per cell) was similar. These values significantly (p less than 0.001) exceeded buccal cell adherence (0.9 +/- 0.2 bacteria per cell). Because cells from ciliated surfaces bind more bacteria than cells from squamous surfaces, bacterial adherence at these respiratory sites may involve different mechanisms. The enhanced bacterial attachment to ciliated cells may assume pathogenic importance when mucociliary function is impaired.

Acetylcysteine↗
PubMed1983

New techniques for the assessment of interstitial lung disease.

The authors succinctly describe the pathogenic mechanisms of this disease and the failures of the traditional diagnostic techniques in providing data about the extent of alveolitis and thus about disease activity and prognosis. The authors then show how the new methods of bronchoalveolar lavage and gallium-67 scanning may provide such information. Next in the discussion is how these techniques are applied to the understanding and management of sarcoidosis and idiopathic pulmonary fibrosis. And finally, the authors propose an integrated approach that uses both the new and traditional methods in the diagnosis and management of interstitial lung disease.

Biopsy↗
PubMedDate not supplied

Efficacy of ciprofloxacin and clarithromycin in acute bacterial exacerbations of complicated chronic bronchitis: interim analysis. Bronchitis Study Group.

In a multicenter, community-based study involving more than 300 primary care physicians in the United States, the efficacy and safety of ciprofloxacin and clarithromycin were compared in the treatment of patients with complicated or severe acute bacterial exacerbations of chronic bronchitis (i.e., those who had failed previous antibiotic treatment within the prior 2 to 4 weeks; those with susceptibility data suggestive of a resistant pathogen; those having three or more acute exacerbations of chronic bronchitis [AECB] within the past year; and those having three or more comorbid conditions). Patients were randomized to either ciprofloxacin (CIP) 750 mg BID or clarithromycin (CLR) 500 mg BID, both administered for 10 days; all patients were treated on an outpatient basis. Clinical response at the end of therapy was the primary efficacy variable. An interim analysis was performed on the results from 743 patients (369 CIP, 374 CLR) with clinical and bacteriologic evidence of a bronchopulmonary infection who had completed an ongoing study as of the end of May 1997. Three hundred nine pathogens were isolated before therapy, including Haemophilus spp (75 isolates), Moraxella catarrhalis (67 isolates), Staphylococcus aureus (55 isolates), and Streptococcus pneumoniae (23 isolates). Seven hundred eighteen patients (97%) were included in the efficacy-valid population. Clinical success at the end of therapy was observed in 90% (272 of 302) and 88% (274 of 313) of efficacy-valid patients treated with CIP and CLR, respectively (95% confidence interval [CI] = -2.4 to 7.6). Corresponding rates for the intent-to-treat population were also 90% (283 of 314) and 88% (281 of 321), respectively (95% CI = -2.3 to 7.5). The bacteriologic response for efficacy-valid patients at the end of therapy was 98% (119 of 122) for CIP-treated and 93% (103 of 111) for CLR-treated patients (95% CI = -0.8 to 10.2). The eradication rates for the three most commonly isolated gram-negative pathogens were 100% for CIP-treated and 95% for CLR-treated patients and 96% each for the two most commonly isolated gram-positive organisms. Superinfections due to respiratory tract pathogens were more common in the CLR group (10 organisms) than in the CIP group (4 organisms). Seventy-four (20%) CIP-treated and 62 (17%) CLR-treated patients reported 118 and 103 respective study-emergent adverse events. Headache, abdominal pain, diarrhea, nausea, and vomiting in CIP-treated patients and diarrhea, nausea, vomiting, and taste perversion in CLR-treated patients were the most commonly reported adverse events. Treatment of patients with complicated or severe AECB with CIP 750 mg BID was associated with rates of clinical success and bacteriologic eradication similar to those with CLR.

Anti-Bacterial Agents↗
PubMedDate not supplied

Etiology, susceptibility, and treatment of acute bacterial exacerbations of complicated chronic bronchitis in the primary care setting: ciprofloxacin 750 mg b.i.d. versus clarithromycin 500 mg b.i.d. Bronchitis Study Group.

Although controversial, antimicrobial therapy for the treatment of acute exacerbations of chronic bronchitis (AECB) appears beneficial in patients with a history of repeated infections, those who have comorbid illnesses, and those with marked airway obstruction. In a community-based, open, randomized trial, the efficacy and safety of ciprofloxacin (CIP) 750 mg and clarithromycin (CLA) 500 mg, each given twice daily for 10 days, were compared in 2180 patients with AECB (1083 CIP, 1097 CLA). Patients were >40 years of age and had complicated/severe AECB episodes defined as at least three episodes within the past year, at least three comorbid conditions, previous failed antibiotic treatment for AECB within the previous 2 to 4 weeks, or community susceptibility data indicating a high number of resistant pathogens. Significant bacterial isolates (>10(5) colony-forming units per milliliter) from homogenized sputa were identified. Susceptibility to a range of antimicrobials was determined by the microbroth dilution technique. The majority of patients were white (83%) and were current or previous smokers (81%). Mean patient age was 62 years. A history of at least three AECB episodes in the previous year was reported by 54% of CIP-treated patients and 53% of CLA-treated patients. Of 777 primary isolates positively identified and cultured from 673 patients, the bacterial pathogens isolated and their incidence included Haemophilus species, 28%; Moraxella catarrhalis, 18%; Enterobacteriaceae, 18%; Staphylococcus aureus, 17%; Streptococcus pneumoniae, 7%; and Pseudomonas aeruginosa, 4%. Beta-lactamase production was found in 38% of Haemophilus influenzae, 10% of Haemophilus parainfluenzae, and 85% of M catarrhalis isolates. Thirty-four percent of S pneumoniae isolates were resistant to penicillin (minimum inhibitory concentration > or =0.12 mg/L). Among the 673 patients who were valid for clinical assessment and had a pretherapy pathogen isolated, clinical success and overall bacteriologic eradication rates at the end of therapy were 93% and 98% for CIP versus 90% and 96% for CLA. The differences between CIP and CLA did not reach statistical significance. Superinfections were reported significantly more frequently in CLA-treated (3%) versus CIP-treated patients (1%). Eradication rates for specific organisms for CIP and CLA, respectively, were Haemophilus species, 99% and 93%; M catarrhalis, 99% and 100%; S pneumoniae, 91% and 92%; and Enterobacteriaceae, 100% and 95%. Drug-related adverse events occurred in 12% of CIP-treated patients and 10% of CLA-treated patients. CIP 750 mg b.i.d. had a higher (but not statistically significant) clinical and bacteriologic cure rate than CLA 500 mg b.i.d. in the treatment of patients with bacteriologically proven complicated/severe AECB. The causative bacterial pathogens of AECB appear to be evolving, with a predominance of gram-negative and other resistant organisms observed. Thus antibiotic therapy for at-risk patients with AECB should include agents that have activity against gram-negative pathogens.

Acute Disease↗
PubMedDate not supplied

The cost of treating community-acquired pneumonia.

Community-acquired pneumonia (CAP) is responsible for an average of 4.5 million visits annually to physicians' offices, emergency departments, and outpatient clinics. However, there have been few studies using national data on the costs of treating CAP. Without such data, it is difficult to assess whether new therapies and treatment strategies are needed to improve patient outcomes. We conducted a retrospective analysis based on national incidence data and paid claims data for patients treated for CAP to assess the frequency of services rendered and costs to the health-care system. Records were selected for the study based on a primary diagnosis of CAP according to the International Classification of Diseases, 9th Revision. Incidence data were derived from the National Health and Nutrition Examination Survey III. Medicare was the primary source of data for patients aged > or =65 years. Data from the National Healthcare Cost and Utilization Project, the National Ambulatory Medical Care Survey, and the National Hospital Ambulatory Medical Care Survey were used to determine the cost of treating patients aged <65 years. We arrived at a total cost of $4.8 billion for treating patients aged > or =65 years and $3.6 billion for treating patients aged <65 years. These calculations were based on the following: 1.1 million hospital discharges resulting in inpatient costs of $4.4 billion (52.4% of the $8.4 billion) for the 0.6 million patients aged > or =65 years and $3.1 billion (36.9% of the $8.4 billion) for the 0.5 million patients aged <65 years. The average hospital length of stay was 7.8 days with an average cost of $7166 for patients aged > or =65 years and 5.8 days with an average cost of $6042 for younger patients. Room and board represented the largest percentage of the average hospital bill for patients with CAP. Inpatient physician service costs were $305 million and $192 million for the > or =65 and <65 groups, respectively. Based on 1.1 million outpatient office visits for those aged > or =65 years and 3.3 million visits for those aged <65, total outpatient costs were $119 million and $266 million, respectively. Given the overwhelming cost burden for CAP in the hospital setting, any new therapy that allows patients to be treated in the outpatient setting could result in significant savings, especially for patients aged > or =65 years.

Adolescent↗
PubMedDate not supplied

Noninfectious respiratory disease in pregnancy.

BACKGROUND: Pregnancy increases the risk of many noninfectious respiratory conditions. OBJECTIVE: To review the clinical presentation and management of a variety of noninfectious respiratory conditions in pregnant women. SUMMARY: Asthma, aspiration pneumonia, venous air embolism, adult respiratory distress syndrome, pulmonary embolism, and deep venous thrombosis may have unique features in pregnant women. CONCLUSIONS: Evaluation and treatment of these diseases and conditions requires an understanding of the normal physiologic alterations that accompany pregnancy and an awareness of the risks of medication use during pregnancy and in the postpartum period.

Adult↗