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PubMed1997

Ultrastructural observations on the human visceral pleura.

Visceral pleura with underlying lung parenchyma was obtained following thoracotomy carried out in 21 patients of both sexes, aged 27-56 years. The samples were taken from unaltered lung regions, and were studied using transmission electron microscopy (TEM). The main components of the visceral pleural tissue complex, mesothelium, basal lamina (BL), elastic membrane (EM), and submesothelial connective tissue layer, are described, with special reference to their relations with the corresponding structures of the lung interstitium. These elements have significant quantitative regional diversities but can be recognized in all investigated cases, and show constant structural uniformity. Two basic mesothelial cell types, squamous (flat) and cuboidal (high) are discerned, based on the differences in size, shape, cell organelles and membrane specialization. The cuboidal mesothelial cells are especially characteristic for the visceral pleura. In addition, an intermediate mesothelial cell that apparently represents a stage in the development of a squamous to a cubiodal mesothelial cell is fairly common. For more rarely, degenerative mesothelial cells are found.

Adult↗
PubMed2001

Electronmicroscopic observations on the visceral and parietal rat's pleura after contralateral pneumonectomy.

The mechanism of compensatory growth and healing of the pleura remains unresolved. Contralateral visceral and parietal (diaphragmatic and costal) pleura were investigated by transmission electron microscopy, following an experimental pneumonectomy (EP). Fifteen young-adult Wistar rats were divided into three groups and with survival times of 1, 5 and 8 days respectively after EP. Three sham-operated (thoracic cavity opened and closed) and three unoperated rats served as controls. One day following EP the superficial mesothelial cells have more microvilli and microvesicles, but a lower number of specialized contacts. Multiplication of extravasal cells leads to an increase of the thickness of the layer over the basal lamina and of the submesothelial layer. Five days after EP the superficial cells show a stratified arrangement in longer sectors of both pleural sheets. Along with typical mesothelial cells there are three new populations of cells: (1) with an abundant granular endoplasmic reticulum and secretory granules, (2) with fibroblast-like characteristics and (3) with a more extensive lysosomal system. The submesothelial layer is thickened due to newly formed blood vessels and collagen bundles. Eight days after EP the mesothelial cells build multi-row arrangement sectors and surround intercellular dilatations covered with microvilli. 'Activated' high mesothelial cells characterize the monolayer sectors. The submesothelial layer remains thicker due to larger collagen bundles and elastic fibers. The changes in the mesothelium and in the connective tissue layer suggest the existence of two periods. The first one is characterized by different mesothelial cell populations, new vasculogenesis and starting of fibrillogenesis. In the second period there are 'activated' mesothelial cells, pleural villi, groups of lymphatic lacunae and significant fibrillogenesis.

Animals↗
PubMedDate not supplied

Parietal pleura and extrapleural space in chronic tuberculous empyema: CT-pathologic correlation.

PURPOSE: The purpose of this work was to describe CT findings of the parietal pleura and extrapleural space in patients with chronic tuberculous empyema and to compare them with histopathologic findings following decortication. METHOD: Chest CT scans obtained from 13 patients with chronic tuberculous empyema who underwent decortication were retrospectively reviewed. All patients were men from 18 to 67 years old (mean 42 years old). CT findings of the parietal pleura and extrapleural space were correlated with histopathologic findings in all patients. RESULTS: Histopathologically, the enhanced parietal pleural peel on CT was fibrous collagenous tissue, and a low attenuated layer with 2 mm thickness within the parietal pleural peel (n = 2) was either a layer of histiocytes or caseation necrosis. The extrapleural space seen as an intermediate attenuation in six patients on CT was the proliferation of vessels, inflammatory cells, and granulomas in loose collagen background. The linear soft tissue attenuation interrupting the extrapleural fat (n = 5) on CT was a collagenous fibrous layer with proliferation of vessels and inflammatory cells. CONCLUSION: A layer of low attenuation in the parietal pleural peel may be due to different episodes of infection. The extrapleural space with intermediate attenuation may indicate ongoing inflammation. Linear soft tissue attenuation interrupting the extrapleural fat represents a fibrous layer rather than the subcostalis muscle.

Adolescent↗
PubMed1987

Pseudoelasticity of excised visceral pleura.

A pseudostrain-energy function is proposed for describing the behavior of excised sheets of canine visceral pleura. Pseudoelastic material constants are determined from experimental biaxial data by employing a nonlinear least-squares algorithm. The agreement between theory and experiment is shown to be quite good. Furthermore, the visceral pleura studied appears to be inelastic and to exhibit in-plane isotropy. Comparison with previous works is discussed.

Algorithms↗
PubMed1991

Fibre distribution in the lungs and pleura of subjects with asbestos related diffuse pleural fibrosis.

The lungs from 13 cases of diffuse pleural fibrosis associated with a history of exposure to asbestos were examined. Samples were taken from the visceral pleura and central and subpleural zones of the lungs for histopathological and mineralogical studies. The fibre type, size, and number were estimated for each of these regions by transmission electron microscopy and energy dispersive x ray analysis. Amphibole fibre counts were raised when compared with a non-occupationally exposed group and matched those seen in cases of pleural plaques, mild asbestosis, and mesothelioma. A wide case to case variation of distribution was seen. No significant difference was apparent between central and subpleural zones, whereas low asbestos counts were found in the pleura; these were mainly short chrysotile fibres. Within the lungs more (45%) of the longer (greater than 4 microns) and thinner (less than 0.25 micron) amphibole fibres were retained in keeping with other studies implicating such fibre profiles in the pathogenesis of asbestos related disease.

Aged↗
PubMed2006

Identification with MRI of the pleura as a major site of the acute inflammatory effects induced by ovalbumin and endotoxin challenge in the airways of the rat.

Inflammatory effects in the rat lung have been investigated, non-invasively by MRI, at early time points (3 and 6 h) after ovalbumin (OA) or endotoxin (LPS) challenges. Six hours after challenge with OA, a strong, even inflammatory signal was present around the periphery of the lung in a region corresponding to the pleura. Histological analysis confirmed the presence of marked edema associated with the pleural cavity of OA-treated animals. Lower levels of pleural edema were observed in MRI and histological evaluation of LPS-treated animals and no abnormality was observed in actively sensitized and naïve, saline-treated groups. Diffuse edematous signals were detected in the lung 3 and 6 h after challenge with OA or LPS; the signal volumes were larger at both time points following OA instillation. Bronchoalveolar lavage (BAL) fluid analysis performed 6 h after challenge revealed increased levels of protein and greater cellular activation in OA- than in LPS-treated animals. Furthermore, increased levels of peribronchial edema were found by histology 6 h after OA. BAL fluid and histological assessments demonstrated that the inflammatory signals were due to edema and not mucus as no significant changes in BAL mucin concentrations or differences in goblet cells were identified between OA or LPS challenge and their respective vehicle groups. Our data show that MRI is able to detect, non-invasively, inflammatory signals in both the lung and the pleura in spontaneously breathing animals, highlighting its potential to study the consequences of pulmonary insults on both sites.

Acute Disease↗
PubMed1986

Effect of hypoxia on permeability of pulmonary endothelium of canine visceral pleura.

To determine if hypoxia increases the permeability of the pulmonary capillaries of the visceral pleura, water and protein movement across visceral pleura of isolated blood-perfused lungs ventilated with 20% O2-5% CO2 or 0% O2-5% CO2 was analyzed in terms of a two-compartment model of fluid exchange. Lungs from mongrel dogs were enclosed in a water-impermeable membrane, thereby creating an artificial visceral pleural space (VPS); fluid flux was determined as the filtration or reabsorption of water and protein in the VPS. Hypoxic vasoconstriction was prevented by adding verapamil to the perfusate. Hydrostatic pressures were continuously monitored and samples of perfusate and pleural fluid were obtained for protein determinations. Pulmonary capillary pressure was varied between 5 and 20 Torr by changing venous pressure while the protein concentration gradient was varied from 0.5 to 6.6 g/dl by introducing different solutions of plasma mixed with saline into the VPS. The hydraulic conductivity (Lp) increased from 4.25 +/- 0.74 to 9.18 +/- 0.67 X 10(-7) ml X s-1 X mmHg-1 X cm-2 and the diffusional permeability (Pd) of protein increased from 1.29 +/- 0.28 to 4.06 +/- 0.44 X 10(-6) cm/s under hypoxic conditions (P less than 0.05). Inhibition of xanthine oxidase by the addition of allopurinol (10 mg/kg body wt) to the perfusate prevented the increase in Lp and Pd observed under hypoxic conditions. We conclude that free radicals generated via xanthine oxidase may be responsible for the increased permeability observed during severe hypoxia.

Animals↗
PubMedDate not supplied

Transthoracic ultrasound of lung and pleura in the diagnosis of pulmonary embolism: a novel non-invasive bedside approach.

The diagnosis of pulmonary embolism (PE) presents a considerable challenge and requires a high index of clinical suspicion from the attending physician. In addition, diagnosing PE may require the use of one or more direct and indirect diagnostic methods. Here, transthoracic sonography (TS) provides an alternative and attractive bedside approach which is based on (1) detecting alterations in the lung parenchyma, (2) involvement of the pleura and (3) peripheral perfusion characteristics associated with thromboembolism. Using a 5 MHz or 3.5 MHz convex scanner, occasionally supplemented by a 7.5 MHz linear scanner or colour-flow Doppler mode, the intercostal areas are systematically examined by TS. Most of the PE-related lesions are localised in the lower lobes of the lung and are often associated with an area of pleuritic chest pain. The characteristic sonographic findings of TS in PE are multiple, hypoechoic, pleural-based parenchymal lesions which adopt a wedge-shape. In addition, a central echo may occasionally be detectable within the lesion. Another regular sonographic feature is the involvement of the pleura manifesting as either localised effusion, basal effusion or both. However, several differential diagnoses such as pneumonia, bronchogenic carcinoma, metastases of extra-pulmonary malignancies, and simple pleurisy need to be excluded. Since localisation of PE-associated lesions may occasionally escape sonographic detection, an inconspicuous sonographic result does not fully exclude PE. As detection of PE-associated lesions using chest ultrasonography has a high specificity and sensitivity, can be rapidly performed, is widely available, non-invasive, cost-effective, and avoids transport of critically ill patients to the investigation site, the technique may prove a valuable tool in the diagnosis of PE at bedside facilitating immediate treatment decision. Further, because the method focuses on detection of peripheral lesions it complements other diagnostic techniques employed when PE is suspected.

Carcinoma, Bronchogenic↗
PubMedDate not supplied

Tuberculous effusion: ADA activity correlates with CD4+ cell numbers in the fluid and the pleura.

BACKGROUND: Adenosine deaminase (ADA) is a commonly used marker in the diagnosis of tuberculous effusion and there is evidence that its production is linked to T cells and monocytes. Data on the correlation between ADA and T cells or macrophages in tuberculous effusions are conflicting. Furthermore, no studies have examined a possible correlation between pleural tissue infiltration and ADA. OBJECTIVES: We undertook this study to examine cell subsets in the fluid and the pleura in tuberculous effusion and their correlation to ADA. The use of cell subsets as a marker in the differential diagnosis was also examined. METHODS: Pleural fluid from 36 patients with tuberculous and 34 patients with malignant effusion as well as pleural tissue biopsies from 16 patients with tuberculous pleurisy were examined. The APAAP and the avidin-biotin complex immunocytochemical methods were used to examine CD4+ T cells and macrophages (CD68+), while ADA activity was measured by the Giusti colorimetric method. RESULTS: Our results showed that, in pleural fluid, CD4+ cells and ADA were significantly higher in tuberculous compared to malignant effusion (p<0.001 for all measurements). In pleural tissue biopsies, macrophages were the predominant cells but CD4+ T cells were also abundant. A significant correlation was found between ADA and CD4+ numbers in pleural fluid and tissue (r=0.45, p<0.01; r=0.75, p<0.001, respectively). ADA had high sensitivity and specificity for differential diagnosis while cell subsets did not. CONCLUSIONS: These results indicate that ADA activity correlates to CD4+ T cell infiltration in the pleura and the fluid. Moreover, ADA but no cell subsets may be used as markers of tuberculous effusion.

Adenosine Deaminase↗
PubMed1997

Distribution and ultrastructure of the stomata connecting the pleural cavity with lymphatics in the rat costal pleura.

We investigated the detailed distribution and ultrastructure of the stomata connecting the pleural cavity and the lymphatics in the rat costal pleura by scanning electron, transmission electron and light microscopy. The mesothelial cells lining the costal pleura appeared as both flattened and thick cell bodies. The thick cells possessed more rough endoplasmic reticula, Golgi complexes, mitochondria, and free ribosomes than the flattened cells. The thick cells were distributed in the intercostal regions each cephalic to the junction of the costal cartilage and bone, and in the band-like regions along the cephalic and caudal sides of each rib in the lateral and dorsal thoracic walls. In the regions lined with thick cells, there were stomata [12.9 +/- 10.3 microns2 (mean +/- SD) in area] consisting of prolongations of thick mesothelial cells and funnel-like projections of lymphatic endothelial cells that came up along the rims of the pores (5.9 +/- 3.2 microns2 in average area) in the submesothelial collagen fiber network. At the stomata, the basal lamina of the mesothelium was continuous with that of the endothelium. The mesothelial cells forming the stomata were mostly in close contact with the endothelial cells, but some gaps also existed between them. Valve-like endothelial flaps were frequently observed wherever endothelial cells constituting the stomata merged into the submesothelial lymphatics. Also present were lymphatic bulges that were either in close contact with the base of the thick mesothelial cells or exposed through the mesothelial pores. The lymphatic network was especially well developed in the submesothelial layer at and around the thick-cell regions. The initial lymphatics drained into the intercostal collecting lymphatics, which in turn led into either the parasternal or paravertebral lymphatic trunk. Our results suggest that the stomata play a major role in absorbing fluids and particulates in the pleural cavity. The thick mesothelial cells appear to secrete chemotactic substances to the endothelial cells. Understanding the heterogeneous distribution of the stomata could prove to be important clinically in inflammatory diseases and tumors in the chest.

Animals↗
PubMed1983

Comparative subgross anatomy of lungs. Pleuras, interlobular septa, and distal airways.

There are major species differences in the subgross anatomy of lungs that influence lung function and the reaction to injury. Variations in lobation and in the structure of pulmonary pleuras, interlobular septums, and distal airways are reviewed and tabulated. Thick pleura is usually accompanied by extensive interlobular connective tissue that forms complete interlobular septums in some species but only incomplete septums in others, resulting in functional differences. In some species, terminal bronchioles end by forming respiratory bronchioles, which in turn form alveolar ducts, whereas in other species terminal bronchioles end by directly forming alveolar ducts, resulting in species differences in acini. The methods used and the biological significance are discussed.

Animals↗
PubMed1984

The effect of changing the contact surface area between pleural liquid and pleura on the turnover of pleural liquid.

To study the dynamics of pleural liquid, 250 ml of saline labeled with markers were injected into the pleural cavity of anesthetized dogs. For 3 h, liquid volume and concentration of these markers were measured. In a control group of dogs, the turnover rate of pleural liquid was 19.6 +/- 5.6 ml/min and lymphatic flow was 0.58 +/- 0.07 ml/min. In a group of pneumonectomized dogs, the turnover rate and lymphatic flow fell to about one fourth of those in the control group. When the left pulmonary artery was occluded, the turnover rate was halved, but lymphatic flow was not significantly different from that in the control group. These results suggest that the turnover rate of pleural liquid is dependent on the area of contact between pleural liquid and pleura and on the blood flow of the pleura. In addition, it appears that changes in pleural liquid volume are dependent on lymphatic flow.

Animals↗
PubMed1986

Experimental evaluation of various available contrast agents for use in the gastrointestinal tract in case of suspected leakage. Effects on pleura.

Intrapleural injections of seven contrast agents were carried out in experimental rats in order to find a safe contrast agent to use in the radiological examination of the upper gastrointestinal tract in cases where leakage outside the upper gastrointestinal tract into the pleural space could be suspected, particularly post-operatively. The contrast agent in such cases could enter the mediastinum, pleura, peritoneum or lungs and bronchi. Hexabrix (May and Baker) and Gastrografin (Schering AG) produced the least tissue reaction in the pleura. Due to the potential risk of aspiration in such cases Gastrografin is not suitable as it is known to produce significant reaction in the lungs and may even prove to be fatal. Hexabrix, therefore, appears to be the safest contrast agent where leakage into the pleural space may be suspected.

Animals↗
PubMed2006

Pedunculated solitary fibrous tumours arising from the pleura.

Solitary fibrous tumour (SFT) is one of the rare tumours which arise from visceral pleura. Klemperer and Rabin first described SFT as a distinct clinical entity among primary pleural tumoUrs in 1931. Approximately 820 cases have been reported in literature to date. The management of patients with SFT is complete resection of the tumour and follow up of the patient to detect any possible late recurrence. In the present paper, we report two cases of pedunculated solitary fibrous tumours of the pleura that appeared as a wandering chest nodule to which surgical resection undertaken at our hospital. The aim is to summarise our experience in the management of solitary fibrous tumour.

Aged↗
PubMed1997

Fibrosis of the lung and pleura and long-term exposure to wollastonite.

OBJECTIVES: The purpose of this study was to determine whether long-term exposure to wollastonite causes fibrosis of the lung and pleura in humans. METHODS: Forty-nine workers (mean exposure 25 years) in a Finnish limestone-wollastonite mine and mill were examined. Their work histories and symptoms of chronic bronchitis were recorded. The chest radiographs were classified according to the classification of the International Labour Office (1980); a radiographic follow-up from 1981 to 1990 was included. Spirometry and diffusion capacity were measured. Four workers underwent high-resolution computed tomography (HRCT) and bronchoalveolar lavage (BAL). Lung tissue specimens were available for 2 workers. Mineral fibers and asbestos bodies were analyzed from the BAL fluid and lung tissue specimens, which were also analyzed for lung fibrosis. RESULTS: Two workers (4%) had small irregular lung opacities (ILO 1/0), 1 worker (2%) ILO 0/1 of the s/t type. HRCT revealed no parenchymal fibrosis in the 2 workers with the ILO 1/0 classification. Of the 9 workers (18%) with pleural plaques, 5 had been exposed to asbestos. Multivariate logistic regression analyses revealed no association of plaques with the duration of wollastonite or asbestos exposure. Wollastonite fibers or bodies were not found in any of the 4 workers who underwent BAL, nor in either of the workers whose lung tissue specimens were available. CONCLUSIONS: No evidence was found that long-term exposure to wollastonite causes parenchymal fibrosis of the lung and pleura. Furthermore, the findings indicate that wollastonite fibers are poorly retained in human lungs.

Adult↗
PubMed2000

MR imaging of the pleura and chest wall.

Evaluation of pleural and chest-wall disease begins with a chest radiograph. In many cases, further evaluation of the chest wall and pleura requires cross-sectional imaging with CT scan or MR imaging. MR imaging is reserved for specific cases of tumors, infections, pleural effusions, and masses. The superior soft-tissue contrast of MR imaging is useful in evaluating the extent of infections and tumors involving the pleura and chest wall. The multiplanar capability of MR imaging aids in the evaluation of chest wall and pleural abnormalities, particularly in the apical regions.

Humans↗
PubMed2000

[Complex use of ultrasound in the diagnosis and treatment of surgical diseases of the lung and pleura].

Since 1980 the N.N. Burdenko Faculty Surgical clinic, I.M. Sechenov Moscow Medical Academy, has been using a combination of high- and low-frequency ultrasounds for the diagnosis and treatment of surgical diseases of lung and pleura in 156 patients for the diagnosis of pleuritis of various genesis, in 40 patients for transthoracic aspiration biopsy of lung tumors in the preoperative period, in 156 patients for pleural puncture and drainage, in 40 patients for the intraoperative differential diagnosis of peripheral lung tumors and for the inspection of hematogenic and lymphogenic metastatic areas, in 100 patients for intraoperative prophylaxis, and in 20 patients for the treatment of acute postoperative pleural empyema. Ultrasound was demonstrated to be of high informative value in diagnosing different pleuritis. Transthoracic aspiration biopsy was shown to have some advantages over standard methods: use of needle catheters for pleural puncture permits one to avoid serious complications (pneumothorax, bleeding, etc). Ultrasound was used in intraoperative diagnosis of peripheral lung tumors for the first time. The use of low-frequency ultrasound for the intraoperative prevention of acute postoperative pleural empyemas promotes reliable sanitation of the pleural cavity, as confirmed by bacteriologic control data. Timely rethoracotomies with low-frequency ultrasound treatment of the pleura promote more rapid inflammation elimination in the pleural cavity and prevents irreversible complications.

Biopsy, Needle↗
PubMed1975

[Pathomorphology of the vascular bed of the lungs and pleura in the presence of hypervolemia of the pulmonary circulation].

Blood and lymphatic vessels of the lungs and the pleura in 23 infants aged below one year, who had died of congenital cardiac defects with hypervolemia of the lesser circulation (coarctation of the aorta, transposition of the major vessels, general arterial trunk in combination with septal defects, open arterial canal and other anomalies) and in 5 dogs with artificial anastomosis of Blalock (3), Cooley (I) and Pootts (I) were studied; In treatment of the materials various histological and histochemical methods, micropreparation and impregnation of total preparation according to Ranvier's and V. V; Kupriyanov's techniques were used. The results obtained showed that an excessive blood content of the lesser circulation was accompanied by onset in the vessels of the lungs and the pleura of various accomodative changes, which were particularly pronounced in the system of microcirculation. It was established that functional insufficiency of the adaptive mechanisms led to the "breakdown" of compensation, impairment of blood and lymph circulation in the terminal vascular bed of the lungs and to grave secondary alterations in the organ. It was shown that early correction of hypervolemia of the lesser circulation in the experiment brought about normalization of hemodynamics in the lungs and more or less full recovery of the structure of microvessels of the regional bed.

Child↗