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G Miserocchi

Publications and source records attributed to G Miserocchi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Physiology and pathophysiology of pleural fluid turnover.

The pleural space contains a tiny amount (approximately 0.3 mL.kg-1) of hypooncotic fluid (approximately 1 g.dL-1 protein). Pleural fluid turnover is estimated to be approximately 0.15 mL.kg-1.h-1. Pleural fluid is produced at parietal pleural level, mainly in the less dependent regions of the cavity. Reabsorption is accomplished by parietal pleural lymphatics in the most dependent part of the cavity, on the diaphragmatic surface and in the mediastinal regions. The flow rate in pleural lymphatics can increase in response to an increase in pleural fluid filtration, acting as a negative feedback mechanism to control pleural liquid volume. Such control is very efficient, as a 10 fold increase in filtration rate would only result in a 15% increase in pleural liquid volume. When filtration exceeds maximum pleural lymphatic flow, pleural effusion occurs: as an estimate, in man, maximum pleural lymph flow could attain 30 mL.h-1, equivalent to approximately 700 mL.day-1 (approximately 40% of overall lymph flow). Under physiological conditions, the lung interstitium and the pleural space behave as functionally independent compartments, due to the low water and solute permeability of the visceral pleura. Pleural fluid circulates in the pleural cavity and intrapleural fluid dynamics may be represented by a porous flow model. Lubrication between lung and chest wall is assured by oligolamellar surfactant molecules stratified on mesothelial cells of the opposing pleurae. These molecules carry a charge of similar sign and, therefore, repulse each other, assuring a graphite-like lubrication.

Absorption↗
PubMed1997

A semiautomatic procedure for edge detection of in vivo pulmonary microvessels and interstitial space.

OBJECTIVE: To develop an algorithm to detect the edges between lung tissue, perivascular interstitium, and microvessel using digital processing of in vivo microscopic images of lung surface. METHODS: A numerical technique was developed to identify three different regions (namely, pulmonary microvessel, perivascular interstitium, and lung tissue) based on their corresponding gray level distributions. We present a theoretical demonstration of the method and a semiautomatic procedure that, once the edges are detected, determines microvascular diameters and perivascular interstitium thickness. RESULTS: Microvessel diameters and perivascular interstitium thickness were calculated for precapillary arteriolar branching (40 to 140 microns) and saved in an ASCII file. CONCLUSIONS: We proved that the maximum value of the moving variance is useful to detect the edge between two adjacent regions whose gray level distributions satisfy the condition: magnitude of sigma Y2 - sigma X2 < or = (mu X - mu Y)2, where mu X, mu Y, sigma X2, sigma Y2 are the statistical moments of the two regions X and Y. Moreover, when the regions have similar means, the above conditions is not met, but the edge between them can be detected by the maximum of the moving variance error.

Algorithms↗
PubMed1997

Cavernous hemangioma of the cavernous sinus. Complete disappearance of the neoplasma after subtotal excision and radiation therapy. Case report.

A case of a 46-year-old woman with a left cavernous sinus hemangioma is reported. The onset of symptoms consisted in left orbital pain and ocular diseases. The suspected diagnosis were among Tolosa-Hunt syndrome and, after neuroimaging researches, cavernous sinus meningioma, trigeminal neurinoma, craniopharyngioma and adenoma with extrasellar extension. The lesion was partially removed with additional neurological deficit of the left 3rd cranial nerve. The patient underwent 7 months later focal radiation therapy of 45 Gray and a 19 months follow-up showed the complete disappearance of the mass and partial recovery of the 3rd cranial nerve function.

Cavernous Sinus↗
PubMed1996

Pulmonary interstitial pressure and proteoglycans during development of pulmonary edema.

In anesthetized adult rabbits, pulmonary perivascular interstitial pressure (P(ip)), measured by micropuncture technique with intact pleural space, averaged -10.5 +/- 1.9 (SD) cmH2O in control conditions, with a wet-to-dry lung weight ratio (W/D) of 4.8 +/- 0.2. Saline infusion (120 ml i.v. over 120 min) induced interstitial edema, increasing P(ip) to 3.62 +/- 1.6 cmH2O with no significant increase in W/D (5.13 +/- 0.1). For intravenous saline infusion exceeding 140 ml, P(ip) decreased to about atmospheric pressure with development of severe edema that was characterized by an increase of W/D ( > 7) with no further change in P(ip). In a separate set of animals, pulmonary interstitial proteoglycans (PGs) were investigated after sequential extraction of the tissue with 0.4 and 4 M guanidinium chloride (GuHCl) under control conditions and with interstitial (100 ml saline load in 100 min) and severe edema ( > 200 ml total infusion). The extractability of PGs increased constantly with increasing W/D. PG content in total extracts was evaluated by determination of hexuronate content which was 195.4 +/- 1.5 micrograms/g dry tissue in control lungs, 217.9 +/- 1.6 in interstitial edema, and 316.4 +/- 2.7 in severe edema. Moreover, edema development was coupled with an increase in efficiency of PG extraction with 0.4 M GuHCl. These findings suggested a weakening of PG interactions with other components of the extracellular matrix (ECM). Electrophoretic and gel-filtration analyses showed that the relative content of PG populations of large molecular size decreased constantly in 0.4 M GuHCl extract with increasing water loading. We propose relating the inflection of P(ip) in the transition from interstitial to severe edema to PG breakdown, which might greatly affect ECM structural organization, including collagen spreading and/or rupture of epithelial layer.

Animals↗
PubMed1995

Pulmonary interstitial pressure in premature rabbits.

By micropuncture technique we measured pulmonary interstitial pressure (Pip) from birth up to 6 h postnatal age in anesthetized and paralyzed cesarian delivered term (31 days gestation) and premature (27 to 30 days gestation) rabbits. In term cesarian delivered rabbits Pip followed the time course of vaginally delivered rabbits, namely, it increased from about zero at birth up to about 5 cmH2O at 2 h, as a result of alveolar fluid reabsorption, subsequently it decreased becoming subatmospheric due to progressive interstitial fluid drainage. In ventilated lung regions of premature rabbits, Pip also peaked to about 5 cmH2O at 2 h but its subsequent decrease was markedly slowed down while in atelectatic regions of premature rabbits Pip remained slightly subatmospheric. Up to 6 h, the wet/dry weight ratio of the lung was higher in premature relative to vaginally and cesarian delivered term rabbits (at birth 8.4 +/- 0.9 vs. 7.5 +/- 0.8). In 29-31 days rabbits, plasma protein concentration at birth was 3.6 +/- 0.5 g/dl (within 95% confidence limits for vaginally delivered rabbits, considered as control) while in 27-28 days rabbit it was 3.1 +/- 0.4 g/dl (at the lower edge of control confidence limits). In the first postnatal hours, the increase in Pip favoured fluid reabsorption into pulmonary microcirculation in term cesarian delivered rabbits and in ventilated regions of premature rabbits. Conversely, in the atelectatic regions of premature rabbits the unchanged Pip value in the postnatal hours favours fluid filtration from microcirculation into lung interstitium.

Age Factors↗
PubMed1995

Estimation of in vivo pulmonary microvascular and interstitial geometry using digital image analysis.

OBJECTIVE: To determine microvascular diameter and perivascular interstitium thickness at the lung surface in the in situ, in vivo lung. METHODS: Microscopic images of the lung surface collected through a "pleural window" by a videocamera were digitized with a monochrome frame grabber (512 x 512 pixels, 8 bits per pixels) to be computer analyzed by image processing techniques. RESULTS: We found that the maxima in the distribution of the standard deviations of gray levels in adjacent neighbors 7 x 7 pixels wide identify the edges between the microvessel lumen and the surrounding perivascular interstitium. Furthermore, the maxima in the distribution of the standard deviation of the standard deviations of gray levels identify the edges between the perivascular interstitium and the lung tissue. CONCLUSIONS: This technique can be applied to microvessels ranging in diameter from 30 microns to 200 microns and perivascular interstitial thickness of the order of 10-150 microns. Our approach allows for the definition of microvascular geometry even for noisy images and represents an improvement compared to other edge detection methods. The proposed analytical procedure may provide a useful tool to study lung fluid balance and microvascular reactivity in the in situ lung in the normal state and in response to a variety of functional conditions.

Animals↗
PubMed1994

Pulmonary interstitial pressure in anesthetized paralyzed newborn rabbits.

In anesthetized paralyzed term newborn rabbits at various postgestational ages (from birth up to 16 days), we measured by micropuncture technique the hydraulic pressure of the pulmonary interstitium (Pip), the extrapleural parietal interstitium, and the pleural liquid. Birth data refer to cesarian-delivered nonbreathing rabbits. Pip increased from 0.5 +/- 2 to 6 +/- 0.7 cmH2O from birth up to 2 h and then decreased, becoming subatmospheric at 5 h and attaining -6 +/- 1.6 cmH2O at 16 days. Over the same period of time, pressure in the extrapleural parietal interstitium and the pleural liquid remained fairly constant at an average value of approximately -1.5 and -2 cmH2O, respectively. The wet-to-dry weight ratio of the lungs decreased from 7.8 +/- 0.4 to 4.9 +/- 0.1 at 16 days. Plasma protein concentration was 4.2 +/- 0.4 g/dl at birth, decreased to 3.2 +/- 0.5 g/dl at 1 h from delivery, and increased back to 4 +/- 0.6 g/dl at 16 days. Pleural liquid protein concentration was 3 +/- 0.1 g/dl at birth and decreased to 1.2 +/- 0.2 g/dl at 16 days. In the first hours of postnatal life, the marked increase in Pip appears to be a key factor in favoring fluid clearance from pulmonary interstitium into the pulmonary capillaries and the pleural space. This factor vanishes after approximately 6 h because of the marked decrease in Pip.

Animals↗
PubMed1993

Pulmonary interstitial pressure in intact in situ lung: transition to interstitial edema.

In anesthetized rabbits (n = 25) subject to slow intravenous saline loading (0.4 ml.min-1.kg-1) for 3 h, we measured pulmonary interstitial pressure (Pip) in intact in situ lungs with glass micropipettes inserted directly into the lung parenchyma via a "pleural window." Measurements were done in apneic animals at the end-expiratory volume with O2 delivered in the trachea. Pip was -10 +/- 1.5 (SD) cmH2O in control and increased to 0.6 +/- 3.8 and 5.7 +/- 3.3 cmH2O at 66 and 180 min, respectively. The wet-to-dry weight ratio (W/D) of the lung was 5.04 +/- 0.2 in the control group and 5.34 +/- 0.7 at 180 min (+6%); the corresponding W/D for intercostal muscles were 3.25 +/- 0.03 and 4.19 +/- 0.5 (+28%). Pulmonary interstitial compliance was 0.47 ml.mmHg-1.100 g wet wt-1. Pulmonary arterial and left atrial pressures were 18.4 +/- 2 and 3 +/- 1 cmH2O in control and increased to 19.5 +/- 2.9 and 4.6 +/- 1.7 cmH2O at 180 min, respectively. Aortic flow (cardiac output) increased from 103 +/- 35 to 131 +/- 26 ml/min; pulmonary resistance fell from 0.17 +/- 0.06 to 0.14 +/- 0.05 cmH2O.min.ml-1 (-18%), suggesting that the increase in Pip did not limit blood flow. The pulmonary capillary-to-interstitium filtration pressure gradient decreased sharply from a control value of 10 cmH2O to 0 cmH2O within 60 min because of the increase in Pip and remained unchanged for < or = 180 min. Data suggest that the pulmonary interstitial matrix can withstand fluid pressures above atmospheric, preventing the development of pulmonary alveolar flooding.

Air Pressure↗
PubMed1993

Model of pleural fluid turnover.

A model of pleural fluid turnover, based on mass conservation law, was developed from experimental evidence that 1) pleural fluid filters through the parietal pleura and is drained by parietal lymphatics and 2) lymph flow increases after an increase in pleural liquid volume, attaining a maximum value 10 times greater than control. From the differential equation describing the time evolution of pleural liquid pressure, we obtained the equation for the steady-state condition ("set point") of pleural liquid pressure: Pss = (KfPi*+KlPzf)/Kf+Kl), where Kf is parietal pleura filtration coefficient, Kl is initial lymphatic conductance, Pzf is lymphatic potential absorption pressure, and Pi* is a factor accounting for the protein reflection coefficient of parietal mesothelium and hydraulic and colloid osmotic pressure of parietal interstitium and pleural liquid. Lymphatics act as a passive negative-feedback control tending to offset increases in pleural liquid volume. Some features of this control are summarized here: 1) lymphatics exert a tight control on pleural liquid volume or pressure so that the set point is maintained close to the potential absorption pressure of lymphatics; 2) a 10-fold increase in Kf would cause only a 2- and 5-fold increase in pleural liquid volume with normal (1.8 g/dl) and increased (3.4 g/dl) protein concentration of the pleural fluid, respectively; and 3) the reduction in maximum lymph flow greatly reduces the range of operation of the control with increased filtration and/or protein concentration of pleural fluid.

Animals↗
PubMed1992

Primary traumatic benign midbrain haematoma in hyperextension injuries of the head.

Primary traumatic brain stem injury occurring in isolation is not universally recognized as a distinct pathological entity which may follow a head injury. We describe two patients with clinical and radiological evidence of primary posttraumatic midbrain haemorrhage occurring in isolation associated with good recoveries. It is suggested that paramedian midbrain syndromes associated with midbrain haemorrhages should be recognized as a distinct, although unusual, complication of hyperextension injury to the head which may have a benign course.

Adult↗
PubMed1992

Microvascular pressure profile in intact in situ lung.

We measured the microvascular pressure profile in lungs physiologically expanded in the pleural space at functional residual capacity. In 29 anesthetized rabbits a caudal intercostal space was cleared of its external and internal muscles. A small area of endothoracic fascia was surgically thinned, exposing the parietal pleura through which pulmonary vessels were clearly detectable under stereomicroscopic view. Pulmonary microvascular pressure was measured with glass micropipettes connected to a servo-null system. During the pressure measurements the animal was kept apneic and 50% humidified oxygen was delivered in the trachea. Pulmonary arterial and left atrial pressures were 22.3 +/- 1.5 and 1.6 +/- 1.5 (SD) cmH2O, respectively. The segmental pulmonary vascular pressure drop expressed as a percentage of the pulmonary arterial to left atrial pressure was approximately 33% from pulmonary artery to approximately 130-microns-diam arterioles, 4.5% from approximately 130- to approximately 60-microns-diam arterioles, approximately 46% from approximately 60-microns-diam arterioles to approximately 30-microns-diam venules, approximately 9.5% from 30- to 150-microns-diam venules, and approximately 7% for the remaining venous segment. Pulmonary capillary pressure was estimated at approximately 9 cmH2O.

Animals↗
PubMed1992

Distribution of diaphragmatic lymphatic lacunae.

The morphology of the submesothelial lymphatic lacunae on the pleural and peritoneal surface over the tendinous and muscular portion of the diaphragm was studied in 10 anesthetized rabbits. The lymphatic network was evidenced by injecting 1 ml of colloidal carbon solution in the pleural (n = 5) or the peritoneal (n = 5) space. After 1 h of spontaneous breathing, the animal was killed and the diaphragm was fixed in situ by injection of approximately 5 ml of fixative in pleural and peritoneal spaces. Then both cavities were opened and the diaphragm was excised and pinned to a support. According to which cavity had received the injection, the peritoneal or the pleural side of the diaphragm was scanned by sequential imaging of the whole surface by use of a video camera connected to a stereomicroscope and to a video monitor. The anatomic design appeared as a network of lacunae running either parallel or perpendicular to the major axis of the tendinous or muscular fibers. The lacunae were more densely distributed on the tendinous peritoneal area than on the pleural one. Scanty lacunae were seen on the muscular regions of both diaphragmatic sides, characterized by large areas without lacunae. The average density of lacunae on tendinous and muscular regions was 6 and 1.7/cm2 for the pleural side and 25 and 3.4/cm2 for the peritoneal side, respectively. The average width of lacunae was 137.9 +/- 1.6 and 108.8 +/- 1.7 microns on the tendinous pleural and the peritoneal side, respectively, and 163 +/- 1.8 microns on the muscular portion of the pleural and peritoneal surfaces.

Animals↗
PubMed1992

Intrapleural fluid movements described by a porous flow model.

We injected technetium-labeled albumin (at a concentration similar to that of the pleural fluid) in the costal region of anesthetized dogs (n = 13) either breathing spontaneously or apneic. The decay rate of labeled activity at the injection site was studied with a gamma camera placed either in the anteroposterior (AP) or laterolateral (LL) projection. In breathing animals (respiratory frequency approximately 10 cycles/min), 10 min after the injection the activity decreased by approximately 50% on AP and approximately 20% on LL imaging; in apneic animals the corresponding decrease in activity was reduced to approximately 15 and approximately 3%, respectively. We considered label translocation from AP and LL imaging as a result of bulk flows of liquid along the costomediastinal and gravity-dependent direction, respectively. We related intrapleural flows to the hydraulic pressure gradients existing along these two directions and to the geometry of the pleural space. The pleural space was considered as a porous medium partially occupied by the mesh of microvilli protruding from mesothelial cells. Solution of the Kozeny-Carman equation for the observed flow velocities and pressure gradients yielded a mean hydraulic radius of the pathways followed by the liquid ranging from 2 to 4 microns. The hydraulic resistivity of the pleural space was estimated at approximately 8.5 x 10(5) dyn.s.cm-4, five orders of magnitude lower than that of interstitial tissue.

Animals↗
PubMed1992

[Neurosurgical aspects of urologic metastases].

Metastases in the central nervous system (C.N.S.) from urological tumors can be spinal or craniocerebral. The experience of 30 patients with spinal and craniocerebral metastases from urological tumors admitted to Neurosurgical Clinic of the University of Milan, is reported. They were 7.5% of the all number of metastases admitted at the Neurosurgical Department, during the same period. The brain metastases constitute 10% of brain metastases diagnosed in this period. Only patients with solitary (to CT scan and NMR) metastasis, and with a general prognosis that allow to an adequate and useful period of survival, are submitted to surgical treatment. 23 patients (76.6%) are surgical treated. The mean survival from the discovery of the C.N.S. metastases was 9 months (9.4 months among surgically treated patients and 7.8 months among those were not operated). Surgical mortality was 13%. Out of patients with survival until 5 months, patients submitted to surgical treatment showed a better quality of life. Our results allow us to affirm that in selected patients surgical removal of solitary metastases, could improve the quality of survival, but is not able to prolong substantially the period of survival.

Adult↗
PubMed1991

Distribution of diaphragmatic lymphatic stomata.

In seven anesthetized rabbits we measured the size, shape, and density of lymphatic stomata on the peritoneal and pleural sides of the diaphragm. The diaphragm was fixed in situ and processed for scanning electron microscopy. Results are from 2,902 peritoneal and 3,086 pleural fields (each 1,620 microns 2) randomly chosen from the various specimens. Stomata were seen in 9% of the fields examined, and in 30% of the cases they appeared grouped in clusters with 2-14 stomata/field. Stoma density was 250 +/- 242 and 72 +/- 57 (SD) stomata/mm2 on peritoneal and pleural sides, respectively, and it was similar over the muscular and tendinous portion of the two surfaces. The maximum diameter ranged from less than 1 to approximately 30 microns, with an average value of 1.2 +/- 3.1 micron. The ratio of the maximum to the minimum diameter and the surface area averaged 2 +/- 1.4 and 0.7 +/- 2.4 micron 2, respectively. The maximum and minimum diameter and surface area values followed a lognormal frequency distribution, suggesting that stomata geometry is affected by diaphragmatic tension.

Animals↗
PubMed1991

Parenchymal stress affects interstitial and pleural pressures in in situ lung.

After resecting the intercostal muscles and thinning the endothoracic fascia, we micropunctured the lung tissue through the intact pleural space at functional residual capacity (FRC) and at volumes above FRC to evaluate the effect of increasing parenchymal stresses on pulmonary interstitial pressure (Pip). Pip was measured at a depth of approximately 230 microns from the pleural surface, at 50% lung height, in 12 anesthetized paralyzed rabbits oxygenated via a tracheal tube with 50% humidified O2. Pip was -10 +/- 1.5 cmH2O at FRC. At alveolar pressure of 5 and 10 cmH2O, lung volume increased by 8.5 and 19 ml and Pip decreased to -12.4 +/- 1.6 and -12.3 +/- 5 cmH2O, respectively. For the same lung volumes held by decreasing pleural surface pressure to about -5 and -8.5 cmH2O, Pip decreased to -17.4 +/- 1.6 and -23.8 +/- 5 cmH2O, respectively. Because Pip is more negative than pleural pressure, the data suggest that in intact pulmonary interstitium the pressure of the liquid phase is primarily set by the mechanisms controlling interstitial fluid turnover.

Animals↗
PubMed1991

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)

Animals↗