D-lactic acid measurements in the diagnosis of bacterial infections.

Body fluids suspected of bacterial infection were cultured and examined for the presence of D-lactic acid, a specific bacterial metabolite. We examined 206 patients and 264 specimens. D-Lactic acid was found in concentrations of greater than or equal to 0.15 mM in 11 of 11 infected and 6 of 40 noninfected ascitic fluids, 6 of 6 infected and 4 of 33 noninfected pleural fluids, 4 of 4 infected and 0 of 13 noninfected synovial fluids, and 26 of 27 infected and 2 of 130 noninfected cerebrospinal fluids. The overall sensitivity was 79.7%, and the specificity was 99.5% when the D-lactic acid concentration was at least 0.15 mM. The most important clinical utility of the D-lactic acid measurement appears to be for patients with bacterial infection in various body compartments and in patients who have already received antimicrobial therapy. An elevation in D-lactic acid may indicate the presence of bacterial infection even when cultures are negative.

[Effects of conditioned media of rat pleural mesothelial cells, transformed in vivo or in vitro by asbestos, on the proliferation of normal mesothelial cells. Comparison with epidermal growth factor, EGF]. / Effets de milieux conditionnés de cellules mésothéliales pleurales de rat, transformées in vivo ou in vitro par l'amiante, sur la prolifération des cellules mésothéliales normales. Comparaison avec le facteur de croissance épidermique, EGF.

The effect of conditioned media obtained from in vivo or in vitro asbestos-transformed rat pleural mesothelial cells on growth of normal mesothelial cells was studied. It was found that both conditioned media led to a reduction of cell proliferation as shown by a decrease in the following parameters: cell number, tritiated thymidine incorporation and percentages of S cells. Similar effects were obtained with EGF (Epidermal Growth Factor).

Application of the Cavalieri principle and vertical sections method to lung: estimation of volume and pleural surface area.

A practical methodology is proposed for the stereological analysis of lung and other organs using recently developed unbiased procedures. This study concentrates on the unbiased estimation of lung volume using Cavalieri's principle compared with the fluid displacement method and measurement of pleural surface area using vertical sections. Furthermore, the proposed design, in addition to the sampling of extensive slices for the initial steps, also allows sampling of vertical sections for light and electron-microscopical stereology. The procedures are described in detail by reference to biological data from the right lungs of four rabbits. We found excellent agreement between estimates of lung volume measured with Cavalieri's principle and those measured by fluid displacement. Pertinent details of the statistical analysis of the sources of variation (namely biological, systematic sectioning and point-counting variation) are given in an appendix.

Pleural protein concentration and liquid volume in spontaneously hypertensive rats.

To determine the effect of systemic vascular hypertension on fluid balance in the pleural space, we studied the spontaneously hypertensive rat (SHR) and its genetic normotensive control, the Wistar-Kyoto rat (WKY). We measured arterial and venous pressures, total protein and albumin concentrations of pleural liquid and plasma, pleural space thickness, and pleural surface pressure in SHR and WKY that were matched for weight (260-300 g). Protein concentration was measured by a manual Biuret test and albumin concentration was measured by the bromcresol green colorimetric method. Pleural liquid thickness was measured in situ using light microscopy. Pleural surface pressure was assumed to equal pleural liquid pressure. In the SHR, total protein and albumin concentrations in pleural liquid were lower than in WKY, and pleural space thickness was larger in SHR than in WKY. These results are consistent with a higher capillary pressure and greater fluid filtration in SHR.

Pleural effusions.

The key to effective evaluation of pleural effusions lies in an understanding of the dynamic nature of its formation and alteration. Trying to fit a specimen neatly into a distinct diagnostic category will not only lead to frustration, but is often unnecessary or incorrect. Combined etiologies are common, and although the possibilities are infinite, certain patterns often present themselves: inflammation frequently complicates congestive failure and neoplasms, hemorrhage is common in neoplastic and chylous effusions, neoplastic effusions may cause transudation from venous obstruction or pericardial stricture, and sepsis is frequently secondary to traumatic effusions. In the presence of atypical findings and the establishment of one cause of pleural effusion, one cannot rule out other operative conditions.

Evaluation of ceftazidime in experimental Klebsiella pneumoniae pneumonia: comparison with other antibiotics and measurement of its penetration into respiratory tissues and secretions.

The activity of ceftazidime was examined in a murine model of Klebsiella pneumoniae pneumonia in which the antibiotic was administered subcutaneously 6 h after intranasal infection and then twice daily for the next three days (i.e. seven doses). In a series of experiments using this test, the dose of ceftazidime giving 50% survival relative to controls (SD50) ranged from 1.0-9.0 mg/kg/dose while the dose required to reduce the log10 cfu/lung by 50% (CD50) ranged from 24-64 mg/kg/dose. Ceftazidime was considerably more effective than cefotiam, amoxycillin-clavulanic acid or kanamycin in the test. Pharmacokinetic studies with ceftazidime showed that no differences in respiratory tract penetration existed between uninfected mice and mice infected for 48 h with K. pneumoniae. The percentage penetration of ceftazidime from serum was 73% for pleural fluid, 44% for tracheal fluid, 27% for tracheal wall tissue and 17% for whole lung tissue after a subcutaneous injection of 100 mg/kg. At this dose, ceftazidime remained at supra-MIC concentrations for 2-3 h in all compartments examined.

Glycosaminoglycan in malignant pleural mesothelioma.

The quantitative analysis on glycosaminoglycan (GAG) in the tumor tissues of five patients with malignant pleural mesothelioma and in the pleural fluid of two patients was performed with the use of biochemical methods. In the tumor tissues, it was found that the average of the total amount of GAG was more than 7.9 times as high as that in adenocarcinoma of the lung, and that hyaluronic acid and chondroitin sulfate were main constituents of mesothelioma GAG. However, there was no significant difference in the content of dermatan sulfate and heparan sulfate between this neoplasm and adenocarcinoma. In the pleural fluid, the amount of hyaluronic acid was about 40 to 230 times higher than that in adenocarcinoma of the lung with the increment of chondroitin sulfate (11-87 times). These findings suggest that a marked increase in the total amount of GAG and the elevation of either the hyaluronic acid or the chondroitin sulfate level, or both, are characteristic abnormalities in malignant pleural mesothelioma.

Pleural effusions and pulmonary edema.

Pleural effusions are a common clinical problem, yet the mechanisms of pleural fluid formation have only recently been investigated. In this article, the anatomy and physiology of the normal pleural space is discussed, as well as the pathophysiology of pleural effusion formation.

Lactic acid levels in pleural fluid from patients with bacterial pleuritis.

Pleural fluid lactic acid estimations were carried out on 60 samples by gas-liquid chromatography. Lactic acid levels in 12 patients with bacterial pleural infection were statistically significantly higher (mean, 287 mg/dl; range, 135 to 482 mg/dl) than in 18 patients with malignancy (mean, 71 mg/dl; range, 24 to 157 mg/dl) and 30 other patients with pleural effusions (mean, 19 mg/dl; range, 10 to 57 mg/dl). The determination of pleural fluid lactic acid may help in differentiating between empyema and nonbacterial pleural effusions in most cases. It is of particular value when antibiotic therapy has commenced before specimen collection and may be useful for monitoring therapy.

The contribution of leukocytes and bacteria to the low pH of empyema fluid.

Empyema fluid characteristically has a low pleural fluid pH, and it has been demonstrated that this fluid has a high acid-generating capacity. To evaluate the contribution of leukocytes and bacteria to the low pH of empyema fluid, an experimental model of empyema was used. After the production of a sterile pleural effusion by turpentine in both normal and neutropenic New Zealand white rabbits, either live Streptococcus pneumoniae, killed Streptococcus pneumoniae, or Acinetobacter, an organism that does not undergo fermentation or produce substantial acid, were injected into the pleural fluid. With these manipulations, the contribution of leukocytes and bacteria alone could be assessed. The results showed that both leukocyte phagocytosis and bacterial metabolism contribute to the low pH of empyema fluid and that the number of polymorphonuclear leukocytes per se in clinically observed ranges is not critical to the change in pleural fluid pH.

Numbers and types of asbestos fibers in subjects with pleural plaques.

The authors analyzed asbestos fibers in lung samples from 20 subjects with pleural plaques discovered on autopsy and compared the findings to their previous analyses of lungs from subjects with little or no asbestos exposure and no plaques. Sixteen of the subjects with plaques had a history of exposure to asbestos. The authors used electron-optical methods and energy-dispersive x-ray spectroscopy to investigate the structure, diffraction patterns, and chemical composition of the asbestos fibers. The subjects with plaques had significantly higher median concentrations than the control subjects for amosite and crocidolite fibers (P less than 0.01) but not for the other fiber types. Minimal microscopic asbestosis was present in the 3 subjects who had the highest amosite concentrations. In the subjects with typical plaques, a history of asbestos exposure, and more fibers than in the control population, the relation of the plaques to asbestos was confirmed; for others, it was uncertain.