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Results for “CAPILLARITY”

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PubMed2005

Pulmonary capillaritis with hemorrhage due to propylthiouracil therapy in a child.

We report on a case of pulmonary capillaritis with diffuse alveolar hemorrhage in a child due to propylthiouracil (PTU). PTU treatment is a rare cause of pulmonary capillaritis in adults; we report on the first case in a pediatric patient. The treatment of pulmonary capillaritis often requires corticosteroid therapy, other immunosuppressive medications, or withdrawal of the causative agent. Our patient recovered completely after treatment with a limited course of corticosteroids and removal of PTU.

Adrenal Cortex Hormones↗

PubMed1996

Capillarity Effects on Viscous Gravity Spreadings of Wetting Liquids.

Highly viscous silicone oils within a wide range of volumes were left to spread on smooth horizontal substrates to investigate the effects of capillarity on viscous gravity spreadings under the condition of complete wetting. The study was centered on the intermediate asymptotic behavior, where the details of the initial liquid distribution are irrelevant. We detected small but appreciable departures from the well-known solution without surface tension forces (viscous gravity self similar solution, or base solution). Two stages are clearly identified in the spreadings. During the first, which is usually rather brief, capillarity does not play an appreciable role on the dynamics of the spreading, i.e., the base solution is a very good approximation. The head of the current displays a wheel-like profile progressively decreasing in size; when the size becomes on the order of the capillary length, this stage ends. The wheel-like configuration cannot be associated either with the rheological behavior of the fluid used or with the initial conditions. To observe this first stage without the influences due to peculiarities of the initial conditions, a proper release of the spreading is needed. The second stage is characterized by a spreading rate below the base solution; the slowing is associated with a change of the current head shape, which takes the form of a wedge as a consequence of capillarity. The rate of advance of the front may still be well approximated by the same power law as given by the base solution, but with a smaller prefactor. In this work we measure the parameters that characterize the flow during both stages; besides, for the second stage, we develop a heuristic calculation which shows that the wedge-like shape of the current head gives place to a higher viscous dissipation rate, thus explaining the observed slowing of the spreading.

Journal Article↗

PubMed1978

Normal and 6-aminonicotinamide impaired development of capillarization in occipital cortex of rat.

During different embryonic and postnatal stages, 6-aminonicotinamide (6-AN) was administered to Wistar albino rats. The capillarization of the occipital cortex has been examined morphometrically. A 6-AN-vulnerable stage of prenatal development was found, which lasted to the 19th prenatal day and which only partly corresponds to the so-called 'critical stage' of capillary sprouting (Kapillarsprossung). Capillary sprouting was not impaired by 6-AN during postnatal stages. Impairment of capillarization by 6-AN might be the result of glial lesion. The importance of glia for capillarization is discussed.

6-Aminonicotinamide↗

PubMed1984

Effects of hypoxia on tissue capillarity in geese.

Tissue capillarity in the gastrocnemius and myoglobin concentrations in the gastrocnemius and heart were determined for hatchling Canada geese, Branta canadensis, following incubation of the embryos under either normoxic (Po2 = 120 torr) or hypoxic (Po2 = 94 torr) conditions. Similar observations were made on a limited number of hatchling bar-headed geese, Anser indicus, a species native to high altitude. Capillary densities were higher and diffusion distances shorter in the hypoxic Canada geese and the bar-headed geese than in the normoxic Canada geese. The concentrations of myoglobin in the heart and gastrocnemius increased with mass, but not as a function of hypoxia. We conclude that bird embryos respond to hypoxia by increasing capillarity. The increased capillarity is found in species native to high altitude when incubated under conditions of normoxia and can be induced in species native to sea level by exposure to hypoxia during development.

Adaptation, Physiological↗

PubMed2004

Angiopoietin/tie receptors system may play a role during reconstruction and capillarization of the hepatic sinusoids after partial hepatectomy and liver necrosis in rats.

Sinusoidal endothelial cells and hepatocytes increase in number after partial resection and necrosis of the liver, and contribute to both reconstruction and capillarization of the sinusoids through interaction with stellate cells. The mechanism underlying such interaction was evaluated regarding angiopoietins and tie receptors essential for blood vessel formation. Hepatic mRNA expressions of angiopoietin-1, angiopoietin-2 and tie-2 were increased at 168h after 70% liver resection with sinusoidal reconstruction in rats, and also at 48h with sinusoidal capillarization in the liver of rats given carbon tetrachloride (CCl(4)). Tie-2 mRNA expression was detected in sinusoidal endothelial cells and stellate cells isolated from normal rats, and in activated stellate cells from CCl(4)-intoxicated rats. The mRNA expressions of angiopoietin-1 and angiopoietin-2 were detectable in Kupffer cells, sinusoidal endothelial cells and stellate cells in normal rats, but increased in activated stellate cells and macrophages after CCl(4)-intoxication. Both angiopoietins and tie-2 were immunohistochemically stained along the sinusoids of 70% hepatectomized rats and in necrotic areas of CCl(4)-intoxicated rats. Angiopoietin-1 and angiopoietin-2 may be involved in both reconstruction and capillarization of the sinusoids in rat liver after partial resection and necrosis through interaction between stellate cells and sinusoidal and vascular endothelial cells via tie-2 receptor.

Journal Article↗

PubMed2003

Muscle fibre size and capillarity in Korean diving women.

AIM: Effects of prolonged habitual cold-water immersion on fibre size and capillarity in vastus lateralis muscle were studied in human beings. The hypothesis tested in the present study was that cold acclimatized human skeletal muscle would have reduced muscle fibre size and higher capillarity, favouring the idea of efficacy of recruitment under cold environment. METHODS: Ten women breath-hold divers (BHDs) and 10 active women (controls CONs) participated in this study. Muscle biopsy was obtained from vastus lateralis and determined fibre type composition and capillary density. RESULTS: A major finding was that all BHDs revealed a markedly smaller cross-sectional area (CSA) in all fibre types than the CONs, or even than any other morphological data reported in previous investigations. Furthermore, mean CSA of type II fibre (range 1205-2766 microm2) was much smaller than type I fibre (2343-4327 microm2). The number of capillaries per fibre in different fibre types in the BHDs was higher than in the CONs (P < 0.001), and diffusional area was smaller in type II fibres than in type I fibres (P < 0.001). The BHDs and the CONs have similarity in the percentage of type I fibres, but type II fibre was predominant in both groups. Interestingly the proportion of type IIx fibre in the BHDs was higher (31%) than in the CONs (22%). No significant difference was found in the thigh circumference between the groups. CONCLUSION: The present study demonstrates that prolonged habitual cold-water immersion may induce a decrease in fibre size and an increase in capillarity in human skeletal muscle.

Adipose Tissue↗

PubMedDate not supplied

Changes in fetal capillaries during preplacental hypoxia: growth, shape remodelling and villous capillarization in placentae from high-altitude pregnancies.

Patterns of fetoplacental angiogenesis and villous growth vary in pregnancies complicated by different forms of fetal hypoxia. This study uses stereological estimators to examine absolute and relative dimensions of villi and fetal capillaries in cases of preplacental hypoxia due to pregnancy at high altitude. Placental samples were drawn from well-defined subjects in different ethnic groups born, raised and completing term pregnancies at low (500 m) and high altitude (3600 m above sea level). Volumes, surfaces and lengths were used to monitor the nett growth of villi and capillaries. Indices of villous capillarization comprised volume, surface and length densities and capillary:villus surface and length ratios. Villus/capillary 'calibre' and shape were quantified using cross-sectional areas, perimeters and shape coefficients (perimeter(2)/area). Group comparisons were drawn by two-way analyses of variance with altitude and ethnicity as the main factors. Volumes, surfaces and lengths of villi, and volumes of capillaries, were reduced at high altitude. Capillary volume declined primarily by formation of narrower microvessels which were more irregular in outline. There were no differences in capillary surface area or length. Cross-sectional sizes and shapes of villi were unaltered. Differences in villous capillarization were confined to higher surface and length densities. Ethnic differences in villous length, capillary length and cross-sectional area tended to favour native groups who are pre-adapted to life at high altitude. Results show that high-altitude pregnancy is not accompanied by increased angiogenesis but may involve enhanced villous capillarization and vascular shape remodelling. Comparisons are drawn with changes seen in maternal anaemia. It is concluded that absolute and relative measures of villous and capillary growth are required lest misinterpretations are introduced by equating hypercapillarization with enhanced angiogenesis or the pattern of capillary branching. The importance of controlling for various potential confounders is also emphasized.

Adaptation, Physiological↗

PubMed1997

Folding funnels and energy landscapes of larger proteins within the capillarity approximation.

The characterization of protein-folding kinetics with increasing chain length under various thermodynamic conditions is addressed using the capillarity picture in which distinct spatial regions of the protein are imagined to be folded or trapped and separated by interfaces. The quantitative capillarity theory is based on the nucleation theory of first-order transitions and the droplet analysis of glasses and random magnets. The concepts of folding funnels and rugged energy landscapes are shown to be applicable in the large size limit just as for smaller proteins. An ideal asymptotic free-energy profile as a function of a reaction coordinate measuring progress down the funnel is shown to be quite broad. This renders traditional transition state theory generally inapplicable but allows a diffusive picture with a transition-state region to be used. The analysis unifies several scaling arguments proposed earlier. The importance of fluctuational fine structure both to the free-energy profile and to the glassy dynamics is highlighted. The fluctuation effects lead to a very broad trapping-time distribution. Considerations necessary for understanding the crossover between the mean field and capillarity pictures of the energy landscapes are discussed. A variety of mechanisms that may roughen the interfaces and may lead to a complex structure of the transition-state ensemble are proposed.

Capillary Action↗

PubMed2006

Effects of experimental type 1 diabetes and exercise training on angiogenic gene expression and capillarization in skeletal muscle.

Diabetes alters microvascular structure and function and is a major risk factor for cardiovascular diseases. In diabetic skeletal muscle, impaired angiogenesis and reduced VEGF-A expression have been observed, whereas in healthy muscle exercise is known to have opposite effects. We studied the effects of type 1 diabetes and combined exercise training on angiogenic mRNA expression and capillarization in mouse skeletal muscle. Microarray and real-time PCR analyses showed that diabetes altered the expression of several genes involved in angiogenesis. For example, levels of proangiogenic VEGF-A, VEGF-B, neuropilin-1, VEGFR-1, and VEGFR-2 were reduced and the levels of antiangiogenic thrombospondin-1 and retinoblastoma like-2 were increased. Exercise training alleviated some of these changes, but could not completely restore them. VEGF-A protein content was also reduced in diabetic muscles. In line with the reduced levels of VEGF-A and other angiogenic factors, and increased levels of angiogenesis inhibitors, capillary-to-muscle fiber ratio was lower in diabetic mice compared to healthy controls. Exercise training could not restore capillarization in diabetic mice. In conclusion, these data illustrate that type 1 diabetes is associated with reduced skeletal muscle capillarization and the dysregulation of complex angiogenesis pathways.

Angiogenesis Inducing Agents↗

PubMedDate not supplied

Chronic obstructive pulmonary disease: capillarity and fiber-type characteristics of skeletal muscle.

BACKGROUND: The purpose of this investigation was to compare capillarity and fiber type proportions of the vastus lateralis muscle between patients with chronic obstructive pulmonary disease (COPD) and healthy subjects. METHODS: Fifteen male subjects were included in the study (8 COPD: 61.0 +/- 1.8 years [mean +/- SEM]; forced expiratory volume in 1 second 42.0 +/- 2.1% predicted; 7 N: age 54.0 +/- 1.1). Subjects were submitted to a symptom-limited maximal exercise test on ergocycle. After a transcutaneous biopsy of the vastus lateralis muscle, sections were cut 8 to 10 microns thick and stained with the Andersen method for capillarity and Stevens method for fiber typing. RESULTS: Patients with COPD had a decrease in peak oxygen consumption compared with healthy subjects (1.2 +/- 0.1 versus 3.0 +/- 0.2 L/min). Number of capillaries per square millimeter was lower in patients with COPD versus healthy subjects (92.6 +/- 16.1 and 213.3 +/- 33.5, P < 0.001); percentages of fiber types were 43.5 +/- 5.5% type I, 56.5 +/- 5.5% type II in COPD, and 56.7 +/- 3.4% type I, 43.2 +/- 3.4% type II in healthy subjects (P < 0.05). In addition, capillaries/fiber ratio was 0.83 +/- 0.05 in COPD, and 1.56 +/- 0.10 in healthy subjects (P < 0.001). CONCLUSION: As expected, patients with COPD showed a decrease in exercise capacity. The muscle analysis results indicate that patients with COPD have a greater proportion of type II fibers and a much lower capillaries/fiber ratio than normal subjects. We conclude that COPD adversely affects fiber type and capillarization of the lower limbs. This could be partly caused by deconditioning in these patients.

Adult↗

PubMed2003

Influence of swim training on cardiac activity, tissue capillarization, and mitochondrial density in muscle tissue of zebrafish larvae.

Larval zebrafish (Danio rerio) of two different age classes ("swim-up" larvae, 9 days old; "free-swimming" larvae, 21 days old) were exposed to either an endurance/continuous training or interval training. Control animals were kept in stagnant water. A comparison of cardiac activity of trained (either endurance or interval) and untrained animals at the end of the training regime revealed no differences in heart rate, end-diastolic and end-systolic ventricular volume, and cardiac output. Training also had no influence on the concentration of erythrocytes in the blood. Thus, at the level of total oxygen transport in the blood, training did not provoke any improvement during the first 32 days of development. Significant changes, however, were observed at the tissue level. In free-swimming larvae [i.e., between 21 and 32 days postfertilization (dpf)] endurance training increased the capillarization of both axial muscle caudal to the anus and the tail fin. In addition, mitochondrial density of red and intermediate muscle fibers increased significantly. In contrast to capillarization, even swim-up larvae, trained between 9 and 15 dpf, were affected. The observed increase in mitochondrial content indicates a high demand for oxygen and energy-rich metabolites for oxidative phosphorylation. In older larvae, this is met by the increase in capillarization that improves the blood supply and with it the required oxygen and metabolite supply of muscle tissue. Both of these adaptational changes result in a reduction of diffusion distances (between capillary and muscle fiber as well as mitochondria) and may contribute to a higher resistance toward oxygen deficiency. Furthermore, this study indicates that plasticity of muscle tissue is already established in early stages of development at both the tissue and cellular levels.

Animals↗

PubMed1991

Diaphragm capillarity and oxidative capacity during postnatal development.

In the cat diaphragm, fiber capillarity, cross-sectional area, and succinate dehydrogenase (SDH) activity were measured across the first 6 wk of postnatal development. Fibers were classified as type I, IIa, IIb, or IIc on the basis of staining for myofibrillar adenosinetriphosphatase (ATPase). Capillaries were identified in sections stained for ATPase at pH 4.2. Fiber cross-sectional areas and SDH activities were quantified using an image-processing system. During postnatal development, the proportions of type I fibers increased while type II fibers decreased. At birth, all type II fibers were IIc. From the 1st to the 2nd postnatal wk, the proportion of type IIc fibers decreased while the numbers of IIa and IIb increased. Thereafter the proportion of type IIb fibers continued to increase while the number of IIa steadily declined. At birth, capillarity, cross-sectional areas, and SDH activities of type I and II fibers were low compared with other postnatal age groups. Fiber cross-sectional areas increased progressively with age. The number of capillaries surrounding type I and II fibers increased markedly by the 2nd wk and then continued to increase at a slower rate. The number of capillaries per fiber area reached a peak by the 2nd wk and then declined as fiber cross-sectional area increased. Postnatal changes in capillarity depended on fiber type, being greatest in IIb. SDH activities of type I and II fibers were initially low during the first 2 postnatal wk and then peaked by the 3rd wk. After the 6th wk, fiber SDH activities decreased to adult values. Among the type II fibers, IIb showed the greatest change in SDH activity during early postnatal development.

Adenosine Triphosphatases↗

PubMed1995

Pulmonary capillaritis and diffuse alveolar hemorrhage. A primary manifestation of polymyositis.

Polymyositis is often complicated by either usual interstitial pneumonitis, diffuse alveolar damage, cellular interstitial pneumonitis, or bronchiolitis obliterans-organizing pneumonia. Pulmonary capillaritis, a distinct interstitial reaction associated with diffuse alveolar hemorrhage, occurs with the systemic vasculitides and some collagen vascular diseases. It has not been described in patients with polymyositis. We describe two patients who developed a relatively acute onset of polymyositis based on the appearance of a severe proximal myopathy, elevated serum creatine phosphokinase levels, compatible electromyographic abnormalities, inflammatory muscle biopsies, and in one case, the presence of serum anti-Jo-1 antibodies. Concomitant with their muscle disease, they developed respiratory failure that proved to be pulmonary capillaritis with varying degrees of diffuse alveolar hemorrhage as well as bronchiolitis obliterans-organizing pneumonia. Although those reactions are reported to occur with other collagen vascular diseases, these two cases are the first reports of pulmonary capillaritis and diffuse alveolar hemorrhage complicating polymyositis.

Adult↗

PubMed2005

Acute pulmonary edema, capillaritis and alveolar hemorrhage: pulmonary manifestations coexistent in antiphospholipid syndrome and systemic lupus erythematosus?

Pulmonary capillaritis and alveolar hemorrhage are rare yet serious and life threatening complications of systemic lupus erythematosus (SLE). Pulmonary manifestations of antiphospholipid syndrome (APS) are similar and include, apart from pulmonary embolism and pulmonary hypertension, pulmonary capillaritis, diffuse alveolar hemorrhage and respiratory insufficiency in patients with catastrophic APS. Herein, we described the radiological features of three patients with pulmonary and SLE-associated APS, manifested with pulmonary edema, capillaritis and alveolar hemorrhage. We observed that the radiological features of pulmonary APS shared close resemblance to those of pulmonary SLE. Based on these findings, we conclude that both entities are not only histologically, but also radiologically indistinguishable from each other, suggesting a mutual pathogenetic mechanism. This raises the question of whether some of the reported lupus pneumonitis cases in the past might be manifestations of APS rather than of SLE.

Acute Disease↗

PubMed2006

Effect of maternal protein restriction in rats on cardiac fibrosis and capillarization in adulthood.

This study examines the effect of maternal protein restriction in rats on levels of cardiac fibrosis, myocardial capillarization, and media:lumen ratio of intramyocardial arteries in adult offspring. Female Wistar Kyoto rats were fed either a normal protein diet (NPD; 20% casein) or a low-protein diet (LPD; 8.7% casein) during pregnancy and lactation. Female offspring (seven per group) were weaned at 4 wk of age and grown to adulthood. At 24 wk of age, the offspring were perfusion fixed. Cardiac fibrosis and media:lumen ratio of intramyocardial arterioles was assessed using image analysis and cardiac capillarization was stereologically investigated. Body weights at 2 and 24 wk of age were significantly reduced (31% and 8%, respectively) in the LPD offspring; however, heart size was not different at 24 wk. Importantly by adulthood, there was a significant 15% increase in left ventricular interstitial fibrosis in LPD offspring. There were no differences in levels of perivascular fibrosis, myocardial capillarization, or in the media:lumen ratio of intramyocardial arteries between groups. Because cardiac fibrosis is associated with impaired cardiac contractility and arrhythmia, our results suggest that induction of interstitial fibrosis may contribute to the increased cardiac disease in adult subjects who were exposed to an adverse intrauterine environment.

Animals↗

PubMed1999

Diffuse alveolar hemorrhage and pulmonary capillaritis due to propylthiouracil.

Propylthiouracil (PTU) has recently been observed to be associated with antineutrophil cytoplasmic antibody (ANCA)-positive small vessel vasculitis, resulting in crescentic glomerulonephritis and, infrequently, diffuse alveolar hemorrhage (DAH). We describe a case of a 23-year-old pregnant woman who developed a perinuclear ANCA and antimyeloperoxidase-positive small vessel vasculitis manifesting as DAH and crescentic glomerulonephritis after she began taking PTU. An open lung biopsy was consistent with pulmonary capillaritis. She responded to corticosteroid therapy and discontinuation of PTU. DAH can be caused by pulmonary capillaritis, bland hemorrhage, or diffuse alveolar damage. To our knowledge, this represents the first documentation of an underlying pulmonary capillaritis in a case of PTU-induced DAH.

Adult↗

PubMed1987

Fiber composition and capillarity in growing guinea pigs acclimated to cold and cold plus hypoxia.

The central portion of the medial head of the gastrocnemius of control (normoxic and normothermic), hypoxia-, cold-, and cold plus hypoxia-acclimated guinea pigs was analyzed for capillary supply and fiber composition to elucidate changes in capillarity induced by environmental stresses. The muscle was cut at midbelly, frozen, sectioned, and stained for myosin ATPase. Fiber cross-sectional areas; percentages of slow-twitch oxidative (SO), fast-twitch oxidative-glycolytic (FOG), and fast-twitch glycolytic (FG) fibers; and numbers of capillaries around each fiber type were measured. Growth rates of all four guinea pig groups were similar. Capillarity was not affected by acclimation to hypoxia. Cold and cold plus hypoxia acclimation led to increased numbers of capillaries around the fiber in all three fiber types. In addition, significant increases in the percentage of FOG fibers and concomitant decreases in the percentage of FG fibers compared to controls were found in cold and in cold plus hypoxia indicating that a transformation of fiber type from FG to FOG had occurred. The increase in FOGs at the expense of the FGs did not occur in the guinea pigs grown in a hypoxic environment. The increased total capillarity in those muscles studied was the result of more capillaries around all fiber types and was not due to simple transformation of fibers.

Acclimatization↗

PubMed1995

[Acute necrotizing capillaritis in an adolescent dying from a a Goodpasture-like pulmonary-renal syndrome].

In this report the authors describe a rare case of pulmonary/renal syndrome like-Goodpasture's disease characterized by a necrotizing acute capillaritis in the lung, kidney, liver, spleen and heart. In the heart the capillaritis was associated with a contiguous acute ischemic lesion. The clinical and pathologic findings of the case suggest that the presence of vasculitis should not exclude a diagnosis of Goodpasture's Syndrome and that the multisystemic capillaritis would demonstrate the organ-non-specificity of anti-glomerular/alveolar basement membrane antibody.

Acute Disease↗