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PubMed1988

Perfused microvascular morphometry during middle cerebral artery occlusion.

This study compared the arteriolar and capillary bed perfusion in the ischemic vs. contralateral cortex 1 h after middle cerebral artery (MCA) ligation in anesthetized rat. Fluorescein isothiocyanate (FITC)-dextran identified the perfused vascular beds. Regional cerebral blood flow (CBF) was monitored with [14C]iodoantipyrine. Morphometric parameters were determined through comparisons of the perfused FITC-labeled vessels with alkaline phosphatase-stained preparations of the total microvascular network. Regional CBF was significantly different when the contralateral cortex (54 +/- 7 ml.min-1.100 g-1) (means +/- SE) and the MCA-occluded cortex (31 +/- 8 ml.min-1.100 g-1) were compared. There were no significant regional differences in any morphometric index of structure in the total microvascular bed. The percentage of the total capillary and arteriolar volume that was perfused in the MCA-ligated cortex was significantly lower than the value obtained from the contralateral cortex. The change in the perfusion pattern of the cerebral microvasculature in the ischemic cortex was not due to vessel blockade. The altered temporal perfusion pattern of capillary and arteriolar vessels in the occluded cortex may be due to an altered microvascular perfusion cycle, longer perfusion pathways, vasoconstriction, or partial vessel obstruction.

Animals↗
PubMed1994

Morphometry of pig coronary venous system.

This is a third part of tripartite morphometric data of the pig coronary blood vessels, giving a complete quantitative description of the arterial tree [Kassab et al., Am. J. Physiol. 265 (Heart Circ. Physiol. 34): H350-H365, 1993], capillary network [Kassab and Fung, Am. J. Physiol. 267 (Heart Circ. Physiol. 36): H319-H325, 1994], and venous tree (this article). Together they provide the quantitative anatomic foundation for coronary hemodynamics. The coronary venules have a unique morphology. Unlike coronary arterioles, which have cylindrical cross sections and a fairly constant diameter in each segment, the venules have approximately elliptical cross sections, are usually wavy in the longitudinal direction, and often converge like fingers to a hand. Measurements were made with the silicone elastomer casting method on five pig hearts. Data on smaller vessels were obtained from histological specimens by optical sectioning. Data on larger vessels were obtained from vascular casts. Arcading veins and anastomoses on the epicardial surface have a unique topology. Data on the number of vessels in each order, the major and minor axes, length, connectivity matrix, and the fractions of the vessels of a given order connected in series in all orders of vessels of the sinusal and thebesian veins are presented. It is shown that of the blood in the coronary blood vessels of a pig heart 27.4% is in the arteries (> 200 microns), 37.1% is in veins (> 200 microns), and 35.5% is in microcirculation (< 200 microns), of which 89.4% is in the capillaries.

Animals↗
PubMed1995

Morphometry and muscle gene expression in hypertrophied hearts from polyomavirus large T antigen transgenic mice.

Transgenic mice expressing polyomavirus large T antigen (PVLT) in cardiomyocytes develop a cardiac hypertrophy in adulthood. Morphometric analysis identified cardiomyocytes enlarged up to ninefold in cross-sectional area in the adult transgenic hearts compared with normal age-matched nontransgenic hearts. Most enlarged cardiomyocytes were found in the subendocardium, whereas normal-sized cardiomyocytes were localized to the midmyocardium. Transgenic hearts did not express detectable skeletal muscle actin mRNA or protein, or skeletal troponin I isoform mRNA. Some, but not all, transgenic hearts expressed an increase in the beta-myosin heavy chain mRNA. All five transgenic mice tested had increased expression of atrial natriuretic factor (ANF) mRNA. Whereas normal hearts expressed three myosin light chain proteins of 19, 16, and 15 kDa, we found that the 19-kDa myosin light chain was not observed in the transgenic hearts. We conclude that adult, PVLT-expressing, transgenic mice developed enlarged cardiomyocytes with an increase in beta-myosin heavy chain and ANF mRNA expression, but a widespread skeletal isoform usage was not present in these transgenic mice. The adult transgenic hearts thus display histological and molecular changes similar to those found in hypertrophy induced by a pressure overload in vivo.

Animals↗
PubMed2006

Morphometry of the extremely thin pulmonary blood-gas barrier in the chicken lung.

The gas exchanging region in the avian lung, although proportionally smaller than that of the mammalian lung, efficiently manages respiration to meet the high energetic requirements of flapping flight. Gas exchange in the bird lung is enhanced, in part, by an extremely thin blood-gas barrier (BGB). We measured the arithmetic mean thickness of the different components (endothelium, interstitium, and epithelium) of the BGB in the domestic chicken lung and compared the results with three mammals. Morphometric analysis showed that the total BGB of the chicken lung was significantly thinner than that of the rabbit, dog, and horse (54, 66, and 70% thinner, respectively) and that all layers of the BGB were significantly thinner in the chicken compared with the mammals. The interstitial layer was strikingly thin in the chicken lung ( approximately 86% thinner than the dog and horse, and 75% thinner than rabbit) which is a paradox because the strength of the BGB is believed to come from the interstitium. In addition, the thickness of the interstitium was remarkably uniform, unlike the mammalian interstitium. The uniformity of the interstitial layer in the chicken is attributable to a lack of the supportive type I collagen cable that is found in mammalian alveolar lungs. We propose that the surrounding air capillaries provide additional structural support for the pulmonary capillaries in the bird lung, thus allowing the barrier to be both very thin and extremely uniform. The net result is to improve gas exchanging efficiency.

Animals↗
PubMed2002

Composition, biophysical properties, and morphometry of plasma membranes in pulmonary interstitial edema.

We evaluated the changes in plasma membrane composition, biophysical properties, and morphology of pulmonary endothelial cells in anesthetized rabbits receiving 0.5 ml. kg(-1). min(-1) saline infusion for 180 min, causing mild interstitial edema. Plasma membrane fractions were obtained from lung homogenates with gradient centrifugation, allowing a sixfold enrichment in caveolin-1. In edematous lungs, cholesterol content and phospholipidic phosphorus increased by 15 and 40%, respectively. These data correlated with morphometric analysis of lungs fixed in situ by vascular perfusion with 2.5% glutaraldehyde, suggesting a relative increase in surface of luminal to interstitial front of the capillary endothelial cells, due to a convoluted luminal profile. In edematous lungs, the fraction of double-bound fatty acids increased in membrane lipids; moreover, the phosphatidylcholine/phosphatidylethanolamine and the cholesterol/phospholipid ratios decreased. These changes were consistent with the increase in fluorescence anisotropy of plasma membrane, indicating an increase in its fluidity. Data suggest that mechanical stimuli elicited by a modest (approximately 4%) increase in extravascular water cause marked changes in plasma membranes that may be of relevance in signal transduction and endothelial cell activation.

Animals↗
PubMed1993

Lung morphometry: a new generation of tools and experiments for organ, tissue, cell, and molecular biology.

Today all structural information of the lung can be quantified and interpreted in the three-dimensional space of real-world biology. Remarkable achievements in the theory and practice of biological stereology are creating a new generation of data suitable for constructing structural hierarchies. Such hierarchies serve to organize and link biological data, thereby providing a framework on which to build new information systems. In this review, we describe the new tools of quantitative morphology and show how they can be used to design new experiments for lung research.

Animals↗
PubMed1985

Morphometry and calcium contents in appendicular and axial bones of exercised ovariectomized rats.

To determine the effects of exercise and ovariectomy on calcium status in selected appendicular and axial bones, female Sprague-Dawley (8-9 mo) rats were assigned to groups based on the following combinations: control (C) or ovariectomized (O); sedentary (S) or exercised (E); and length of treatment (2 or 4 mo). Exercise consisted of treadmill running for 1 h/day, 5 days/wk at a speed of 14.1 m/min and 8 degrees elevation. After death, femurs, tibia-fibula complexes, ribs (T7), and vertebrae (T7) were excised, cleaned, and weighed, and selected morphometrics were measured. Tensile strength was measured for the femurs, and all bones were then acid-hydrolyzed and calcium concentration determined spectrophotometrically. Bone [Ca2+] was significantly greater for CE and OE animals when compared with their sedentary counterparts (CS, OS). Within 4 mo calcium losses were evident in the femur and tibia of the ovariectomized animals, and the moderate exercise program was of insufficient intensity to alter this loss. The average stress to failure for femur from all groups was 1.13 +/- 0.11 N/m2. However, the effects of exercise appeared beneficial in the axial bones where [Ca2+] increased in the ovariectomized animals.

Alkaline Phosphatase↗
PubMed1987

Morphometry, histochemistry, and contractility of dystrophic hamster diaphragm.

Differences in gross and microscopic morphology, fiber-size distribution, and fiber-type composition were present in the diaphragm of 35-, 130-, and 180-day-old dystrophic (Bio 14.6) compared with age-matched control (Bio F1B) hamsters. The dystrophic diaphragm was significantly thicker than the control at 130 and 180 days. Increases in wet-to-dry weight ratios, connective tissue per unit area, and muscle fiber number suggest that increased tissue hydration, fibrosis, and fiber hyperplasia contribute to diaphragm hypertrophy. Marked variations of fiber areas and diameters were evident in each fiber type at each age, but generalized atrophy predominated over hypertrophy, resulting in significant decreases in cross-sectional areas of each fiber type. Significant differences in fiber-type composition were noted in the dystrophic vs. control diaphragm at each age: at 35 days the percentage of slow-oxidative fibers was lower and in fast-oxidative fibers was higher; at 130 days the percentage of fast-oxidative fibers remained elevated; at 180 days the percentage of fast-glycolytic fibers was reduced. In vitro contractility studies of 130-day-old animals showed that twitch and peak tension development were significantly lower in the dystrophic compared with the control diaphragm, whereas optimal length, contraction time, and half-relaxation time were within control limits. Microscopic and physiological abnormalities were also present in the soleus of 130-day-old dystrophic animals. As in the diaphragm, fiber areas were reduced, connective tissue area increased, and peak and twitch tension decreased significantly compared with the control soleus. The histopathological and pathophysiological changes in the diaphragm correlated well with each other and are consistent with the slowly evolving inability of the dystrophic hamster to increase tidal volume and minute ventilation in response to a hypercapnic challenge.

Animals↗
PubMed1995

Thyroxine affects ventilation, lung morphometry, and necrosis of diaphragm in dystrophic hamsters.

Male dystrophic hamsters (DH) were treated with pellets containing thyroxine (T hamsters) or placebo (P hamsters) for 8 wk. O2 consumption, ventilation, and ventilation in response to 8% CO2 in O2 and 10% O2 in N2 were evaluated 1 and 8 wk after treatment began. O2 consumption was elevated in T hamsters at 1 and 8 wk, whereas ventilation was similar in the two groups on the first week. By 8 wk, ventilation and ventilatory responses to hypoxic and hypercapnic challenges were 100% greater in T than in P hamsters (P < 0.05). Morphometric evaluations at the end of the treatment period indicated that air space surface density, tissue volume density, and surface density-to-air space volume ratio of the lung parenchyma were greater (P < 0.05) in T than in P hamsters. In contrast, chord length within the lung parenchyma was shorter and necrosis in the diaphragm and tongue, but not in the heart, was lower (P < 0.05) in T than in P hamsters. Taken together, these results suggest that T treatment of DH for 8 wk affects O2 consumption, ventilation, lung architecture, and skeletal muscle without increasing triiodothyronine levels.

Animals↗
PubMed1977

Morphometry of the distal air spaces in lungs of aging dogs.

Changes in pulmonary morphometric measurements with age were examined by manual and automated methods in 14 normal beagle dogs aged 289-3,694 days. The study was instituted as a statistical adjunct to previous morphological studies on these dogs that showed anthracosis and associated dilatations in the distal airways in aged dogs. With increasing age, the volumetric density of alveolar ducts increased concomitantly with decreases in the volumetric densities of alveoli and alveolar parenchymal tissue. The numerical and surface densities of alveoli also decreased with age. A comparison of an automated method with accepted manual methods showed no significant differences in stereological measurements of the distal air spaces with the exception of an overestimation of surface density by the automated method. The automated method was found to be a satisfactory method for evaluating the relative differences in alveolar surface densities and the volumetric densities of respiratory air space and parenchymal tissue.

Aging↗
PubMed1980

Lung morphometry in guinea pigs acclimated to cold during growth.

Weanling male guinea pigs, Cavia porcellus [initial weight (W) = 200-250 g], were chronically acclimated to 5 degrees C for 2-18 wk before they were killed. Controls were raised at 22 degrees C. Food and water were given ad lib., and growth was the same in both groups. Under pentobarbital anesthesia (30 mg/kg), lungs were fixed by tracheal instillation of glutaraldehyde and processed for electron microscopy. Lung volume (VL, ml) was measured by displacement; alveolar and capillary surface areas (SA and Sc, m2) were determined morphometrically. Regressions of lung variables vs. W at 22 degrees C (range of W = 89-1,274 g) were as follows: VL = 0.175 W0.676, SA = 0.0097 W0.759, and Sc = 0.0055 W0.825; for 5 degrees C animals (range of W = 239-1,074 g): VL = 0.384 W0.584, SA = 0.0334 W0.594, and Sc = 0.032 W0.562. The total arithmetic mean thickness of lung tissue did not vary with W, and averaged 1.39 microns at 22 degrees C and 1.41 microns at 5 degrees C. VL, SA, and Sc are significantly greater in 5 degrees C guinea pigs than in 22 degrees C animals when W = 300-600 g, but are indistinguishable between groups when W > 700 g. Chronic increases in oxygen consumption, which occur with prolonged exposure to cold, result in accelerated lung development in immature guinea pigs toward normal adult dimensions.

Acclimatization↗
PubMed1983

Morphometry of cat pulmonary venous tree.

Morphometric data of the pulmonary veins in the cat right lung are presented. Silicone elastomer casts of the right lungs of five cats were made, measured, counted, and analyzed. The Strahler system is used to describe the branching pattern of the vascular tree. These data are needed for the physicomathematical approach to pulmonary circulation. For all the pulmonary blood vessels lying between the left atrium and the capillary beds, there are a total of 10 orders of vessels in the right upper lobe, 9 orders of vessels in the right middle lobe, and 11 orders of vessels in the right lower lobe. The ratios of the diameters, lengths, and the number of branches in successive orders of vessels are called the diameter, length, and branching ratios, respectively. For the cat pulmonary venous tree, the average branching ratio is 3.521, the average diameter ratio is 1.727, and the average length ratio is 2.402 for vessels of orders 1-3 and 1.532 for vessels of orders 4-10.

Animals↗
PubMed1993

Morphometry of methacholine-induced bronchoconstriction in the rat.

It has been suggested that parenchymal viscoelasticity accounts for a large proportion of resistive pressure losses induced by smooth muscle agonists. We used morphometric methods to evaluate the relative contributions of parenchyma and airways to mechanical changes during methacholine- (MCh) induced bronchoconstriction. We measured tracheal pressure and tidal volume in 17 open-chest mechanically ventilated Sprague-Dawley rats (frequency = 1.5 Hz, tidal volume = 2 ml, positive end-expiratory pressure = 5 cmH2O) after saline (n = 7, C), 16 mg/ml MCh (n = 5, L), and 256 mg/ml MCh (n = 5, H) aerosols. We calculated pulmonary resistance (RL) and elastance (EL) by fitting the equation PL = VRL + VEL + K, where PL is transpulmonary pressure, V is flow, and V is volume. V was obtained numerically from V. Lungs were rapidly frozen in liquid N2 30 s after aerosolization and processed with freeze substitution. Using midsagittal slices of left lung, we measured airway narrowing as the ratio of lumen area (aBM) subtended by the basement membrane perimeter (LBM) to predicted maximal lumen area (ABM = LBM2/4 pi). Air space size was estimated as mean linear intercept (Lm) and parenchymal distortion as standard deviation of linear intercepts (SDi). Lm was increased in L and H animals, reflecting hyperinflation; aBM/ABM in 0.17- to 0.43-mm-diam airways decreased progressively from C to L to H animals, reflecting bronchoconstriction. By use of stepwise multiple linear regression, the contribution of Lm to variance in mechanics was found to consistently exceed or equal that of aBM/ABM. SDi contributed little once Lm was taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗
PubMed1995

Lung water measurement by nuclear magnetic resonance: correlation with morphometry.

Estimates of lung water content obtained from nuclear magnetic resonance (NMR) and morphometric and gravimetric measurements were compared in normal and experimentally injured rats. Average lung water density (rho H2O) was measured by an NMR technique in excised unperfused rat lungs (20 normal lungs and 12 lungs with oleic acid-induced edema) at 0 (full passive deflation) and 30 cmH2O lung inflation pressure and in vivo (4 normal rats and 8 rats with lung injury induced by oleic acid or rapid saline infusion). The rho H2O values were compared with morphometric measurements of lung tissue volume density (Vv) obtained from the same lungs fixed at corresponding liquid-instillation pressures. A close correlation was observed between rho H2O and Vv in normal and injured excised lungs [correlation coefficient (r) = 0.910, P < 0.01]. In vivo rho H2O was also closely correlated with Vv (r = 0.897, P < 0.01). The correlation coefficients between rho H2O and gravimetric lung water content (LWGr) were lower in the excised lung group (r = 0.663 and 0.692, respectively, for rho H2O at 0 and 30 cmH2O lung inflation pressure, P < 0.01) than in the in vivo study (r = 0.857, P < 0.01). Our results indicate that NMR techniques, which are noninvasive and nondestructive, provide reliable estimates of lung water density and that the influence of lung inflation on rho H2O is important (compared with the effect of lung water accumulation in lung injury) only in the presence of deliberately induced very large variations in the lung inflation level.

Animals↗
PubMed1996

Morphometry of the human pulmonary vasculature.

The morphometric data on the branching pattern and vascular geometry of the human pulmonary arterial and venous trees are presented. Arterial and venous casts were prepared by the silicone elastomer casting method. Three recent innovations are used to describe the vascular geometry: the diameter-defined Strahler ordering model is used to assign branching orders, the connectivity matrix is used to describe the connection of blood vessels from one order to another, and a distinction between vessel segments and vessel elements is used to express the series-parallel feature of the pulmonary vessels. A total of 15 orders of arteries were found between the main pulmonary artery and the capillaries in the left lung and a total of 15 orders of veins between the capillaries and the left atrium in the right lung. The elemental and segmental data are presented. The morphometric data are then used to compute the total cross-sectional areas, blood volumes, and fractal dimensions in the pulmonary arterial and venous trees.

Adult↗