Comparative permeability of canine visceral and parietal pleura

To determine the permeability of canine pleural mesothelium, visceral and intercostal parietal pleura from mongrel dogs was carefully stripped from the underlying tissue and mounted as a planar sheet in a Ussing-type chamber. The hydraulic conductivity (Lp) was determined from the rate of volume flux in response to hydrostatic pressure gradients applied to either the mucosal or serosal surface of the pleural membrane. The diffusional permeability (Pd) of radiolabeled water, sucrose, inulin, and albumin was determined under equilibrium conditions from the unidirectional tracer flux. The Lp of the visceral pleura was 0.39 +/- 0.032 (SE) X 10(-4) ml.s-1.cmH2O-1.cm-2 and that Lp of parietal pleura was 1.93 +/- 0.93 X 10(-4) ml.s-1.cmH2O-1.cm-2 (P less than 0.001). The Pd of the visceral pleura ranged from 12.21 +/- 0.45 X 10(-4) cm/s for 3H2O to 0.34 +/- 0.03 X 10(-4) cm/s for [3H]albumin. The Pd of the parietal pleura for water and sucrose was similar to that of the visceral membrane, whereas its Pd for the larger inulin and albumin molecules was greater than that of visceral pleura (P less than 0.01). A spontaneous potential difference could not be detected across either membrane. The relatively higher parietal pleural Lp and Pd for larger solutes is probably due to the presence of stomata in this membrane. These results indicate that both the parietal and the visceral pleura are extremely permeable tissues which offer little resistance to water and solute flux.     

Culture procedure of mesothelial cells from the rat parietal pleura

Cultures were made of mesothelial cells obtained by scraping the parietal pleura of the adult rats. The growth was restricted to close polyhedric epithelial-like cells, forming a monolayer. The cellular proliferation continued until the 7th day, followed by a stationary phases. In subcultures the mesothelial cells kept their epithelial type. The cultures were stopped on the 20th day.     

Electronmicroscopic observations on epidermoid (squamous cell) carcinomas of the lung

Five epidermoid (squamous cell) carcinomas of the lung histopathologically diagnosed were ultrastructurally analysed; special attention was given to the poorly differentiated-immature areas of proliferation. Wide intercellular spaces between irregular cytoplasms with protrusions and microvilli, a high incidence of indentations of nuclear membranes, a large amount of nuclear bodies, shape, size and structure anomalies of mitochondria, a great number of desmosomes and of tonofilaments and tonofibril bundles and their relations with desmosomes and with the finger-like cytoplasmic expansions were noticed. A few secretory granules were also present in these poorly differentiated-immature areas of epidermoid carcinomas of the lung.     

Regional blood flow to canine parietal pleura and internal intercostal muscle

Transcapillary Starling forces in the parietal pleura and the underlying interstitium may potentially contribute to the exchange of fluid across this barrier. However, the extent of blood flow to the parietal pleura has not been measured. Thus, using standard microsphere techniques, we compared blood flow to the parietal pleura, including the subpleural interstitium, with blood flow to the adjacent internal intercostal muscle, as well as with flows to other serous tissues, including mediastinal pleura, pericardium, and parietal peritoneum, in anesthetized dogs that were either breathing spontaneously (n = 9) or ventilated to control arterial PCO2 (n = 5). Blood flow (ml.min-1.g-1) was measured after 20 min of equilibration in four successive body positions: right lateral decubitus, supine, left lateral decubitus, and prone. Overall, flow to parietal pleura was not different in spontaneous [1.07 +/- 0.14 (SE)] and mechanically ventilated animals (0.74 +/- 0.11). Flow to the internal intercostal muscle was significantly less than pleural blood flow, averaging 0.24 +/- 0.03 and 0.16 +/- 0.03 in the same groups, although again there was no effect of ventilation mode. Blood flow to other serous tissues in the thoracic cavity, specifically the mediastinal pleura (0.67 +/- 0.14) and pericardium (0.88 +/- 0.22), was similar to parietal pleural flow, whereas that to the parietal peritoneum was an order of magnitude lower (0.09 +/- 0.02, P less than 0.05). Changing body position had no effect on blood flow to any of the sampled tissues. Blood flow to the dorsal aspect of the chest wall muscle in spontaneously breathing animals tended to be greater than that to lateral or ventral portions of the chest wall.(ABSTRACT TRUNCATED AT 250 WORDS)     

Permeability-surface area product and reflection coefficient of the parietal pleura in dogs.

The parameters describing the permeability of the parietal pleura to liquid and total plasma proteins were measured in five anesthetized adult dogs. Small areas of parietal pleura (approximately 1 cm2) and the underlying endothoracic fascia were exposed through resection of the skin and the intercostal muscles. The portion of the thorax containing the pleural windows was removed from the chest and fixed over a bath of whole autologous plasma, the inner parietal pleural surface facing the bath. Small hemispheric Perspex capsules (surface area 0.28 cm2) connected to a pressure manometer were glued to the pleural windows; a subatmospheric pressure was set into the capsule chamber to create step hydraulic transpleural pressure gradients (delta P) ranging from 5 to 60 cmH2O. Transpleural liquid flows (Jv) and protein concentration of the capsular filtrate (Cfilt) and of the plasma bath were measured at each delta P. The transpleural protein flux (Js) at each delta P was calculated by multiplying Jv by the corresponding Cfilt. The hydraulic conductivity (Lp) of the parietal pleura was obtained from the slope of the Jv vs. delta P linear regression. The average Lp from 14 capsules was 9.06 +/- 4.06 (SD) microliters.h-1.cmH2O-1.cm-2. The mathematical treatment of the Js vs. Jv relationship allowed calculation of the unique Peclet number at the maximal diffusional protein flux and a corresponding osmotic permeability coefficient for plasma protein of 1 x 10(-5) +/- 0.97 x 10(-5) cm/s. The reflection coefficient calculated from the slope of the linear phase of the Js vs. Jv relationship was 0.11 +/- 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)     

Electronmicroscopic observations on lysis of Trypanosoma cruzi epimastigote by normal rabbit serum.

The lytic effects of serum from a non-immunized rabbit on epimastigotes of Trypanosome cruzi were studied by electronmicroscopy. The first detectable change was the appearance of a fuzzy deposit over the whole surface of the epimastigote. Soon after this, pellicular microtubules disappeared without change of axonemal microtubules. Circular lesions were observed by negative staining, corresponding to the lesion of antibody-mediated lysis caused by complement.     

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.     

A study of the two-way transport of horseradish peroxidase across the visceral pleura

Summary The authors report on a study of the transpleural transport of horseradish peroxidase after intrapleural and intracardiac application. Following intrapleural introduction, a retention of the marker on the apical membrane of mesothelial cells was observed, with subsequent transcellular transfer after incorporation into microvesicles. Following intracardiac injection, the marker moved out of the pulmonary capillaries across the endothelial vesicles and progressed to the pleural cavity across the intercellular spaces and mesothelial vesicles. With either route of injection, reaction product was noted in the basal lamina of the mesothelium, elastic membrane, alveolar macrophages and pneumocytes type II.Dedicated to Professor Dr. T.H. Schiebler on the occasion of his 65th birthday     

A study of the two-way transport of horseradish peroxidase across the visceral pleura

The authors report on a study of the transpleural transport of horseradish peroxidase after intrapleural and intracardiac application. Following intrapleural introduction, a retention of the marker on the apical membrane of mesothelial cells was observed, with subsequent transcellular transfer after incorporation into microvesicles. Following intracardiac injection, the marker moved out of the pulmonary capillaries across the endothelial vesicles and progressed to the pleural cavity across the intercellular spaces and mesothelial vesicles. With either route of injection, reaction product was noted in the basal lamina of the mesothelium, elastic membrane, alveolar macrophages and pneumocytes type II.     

Ultrastructure of synapses of the parietal and visceral ganglia of Helix pomatia

Types of synaptic contacts and peculiarities of their distribution in the neuropil of the parietal and visceral ganglia of the edible snail (Helix pomatia) CNS have been studied electron microscopically. Ultrastructure of dendrites and axons has been identified. Dendrites with spinous++ processes, polymorphism of synaptic contacts have been revealed. Besides axo-axonal synapses, axo-dendritic synapses are demonstrated on the trunks and on the spinous processes of the dendrites, as well as dendro-dendritic and serial synapses. Unevenness in distribution of synaptic contacts is shown in the neuropil. The areas of the greatest concentration of the synapses are the "synaptic fields". Peculiarities in distribution of the synaptic contacts are demonstrated in the parietal and visceral ganglia.