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Results for “CAPILLARITY”

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At least 127 records · Page 7Linked to original sources

PubMed2006

Decreased capillarization and a shift to fast myosin heavy chain IIx in the biceps brachii muscle from young adults with spastic paresis.

Muscle spasticity and paresis are conditions that occur secondary to upper motor neuron lesions. The co-existence of decreased motor unit recruitment and intermittent over-activity generates confusion concerning the effect on muscle fiber characteristics. In order to increase the knowledge about the effect of upper motor lesion on capillarization and muscle fiber composition, the biceps brachii muscle from seven young adults with long duration of spastic paresis and seven age-matched controls were analyzed using morphological and enzyme- and immuno-histochemical techniques. The spastic muscles had a 38% lower capillary density (p=0.002), 30% fewer capillaries around each muscle fiber (p=0.02), and 16% fewer capillaries when related to the fiber size (p=0.04). The frequency of fibers expressing myosin heavy chain (MyHC) IIx increased (30% vs. 4%, p=0.006), while the percentage of fibers expressing MyHC I and MyHC IIa, respectively, decreased (22% vs. 46% and 7% vs. 29%, p<0.01). The high proportion of muscle fibers with low oxidative capacity and low capillary supply indicates that biceps brachii muscle from patients with upper motor lesions fatigue more easily than normal controls. We also observed a significantly higher variability in fiber size for fibers expressing MyHC I (p<0.04), and, in three of the subjects, a small amount of small fibers expressing developmental MyHCs was found. These results suggest that, although intermittent stretch reflex contractions might have an impact on the muscle characteristics in spastic paresis, the muscle phenotypic properties are more adapted to decreased voluntary motor unit recruitment.

Adolescent↗

PubMed2005

Pulmonary capillaritis in children: a review of eight cases with comparison to other alveolar hemorrhage syndromes.

OBJECTIVE: To review clinical, laboratory, and outcome characteristics of children diagnosed with pulmonary capillaritis (PC), a small-vessel vasculitis, presenting as diffuse alveolar hemorrhage (DAH), and to compare these findings with those for children with other alveolar hemorrhage syndromes. STUDY DESIGN: A retrospective chart review of patients who underwent a lung biopsy because of a clinical suggestion of pulmonary hemorrhage. RESULTS: PC was identified in 8 of 23 patients. In these patients, cough, crackles, and hypoxia were common. Alveolar infiltrates on radiography and anemia were present in 7 of 8 cases. Serologic evidence of a systemic vasculitis was present in 50% of patients. High-dose corticosteroids proved effective in controlling alveolar hemorrhage in all cases. There were no presenting signs or symptoms that could differentiate patients with PC from those with non-immune-mediated alveolar hemorrhage. In general, patients with PC had a lower hematocrit and higher erythrocyte sedimentation rate (ESR). CONCLUSION: Children presenting with lower respiratory tract symptoms, chest x-ray abnormalities, and anemia should undergo evaluation for PC, as early initiation of immunosuppression can be lifesaving and organ sparing. No clinical signs to differentiate immune and non-immune-mediated alveolar hemorrhage were evident in this study.

Biopsy↗

PubMed2000

Does capillarity influence chemical reaction in drops and bubbles? A thermodynamic approach.

After a brief introduction on the variables which describe the physico-chemical properties of a fluid surface, this paper compares, in a very simple way, the equilibrium constant of homogeneous and heterogeneous reactions taking place in spherical micro-objects (uncharged and charged droplets and bubbles) and in media bordered by a flat interface. This quantity is by definition the exponential of the dimensionless standard chemical affinity whose values (< or = 0, > or = 0) may indicate the direction and the importance of the reaction (strictly true when the mixing term of the affinity is zero). The classical thermodynamic approach combined with the Laplace equation shows that: (i) high surface tension and high curvature influence the equilibrium constant, this effect being, however, much more important for bubbles than for droplets; (ii) charges on droplets reduce this effect; (iii) the constant of reaction taking place in the vapour in contact with a charged droplet depends significantly on the electric field pressure; (iv) reactions in droplets dispersed in the liquid phase are discussed and, in particular, capillarity seems to play a negligible role on reactions in micro-emulsions; (v) the surface amount of a gas bubble component transferred in the continuous liquid can be related to capillary quantities; (vi) expanding (or shrinking) bubble induced by a chemical reaction is analysed by using an extended Laplace law which includes the volumetric flow rate; (vii) the Laplace law is discussed in the frame of the choice of the dividing surface. Numerous actual examples from the atmosphere, sonochemistry and metallurgy illustrate the theory proposed. One of the interest, among other points, is that small objects (specially bubbles) give the potentiality to obtain, for steady or (near) equilibrium states, large amount of components which would not be possible when dealing with large reservoirs.

Air↗

PubMed1997

The capillarity of left ventricular tissue of rats subjected to coronary artery occlusion.

OBJECTIVE: The effects of chronic coronary occlusion on the capillarity of left ventricular tissue in rat heart. METHODS: The heart was exposed through a left-sided thoracotomy in ethylether-anesthetized and ventilated rats. The left coronary artery was occluded with a thin suture and the thorax was closed. Thirty days after the surgery the heart was removed and cross-sections were made for morphometric analyses. RESULTS: The cross-sectional area of cardiomyocytes increased markedly in the subepi- and subendocardia with a concomitant increase in the capillary to myocyte ratio. The total capillary density increased in the non-ischemic zone. The balance between the increase in capillary density and myocyte hypertrophy was assessed from the capillary domain area (CDA). CDAs were significantly smaller for the venular capillary portion in the subendocardial non-ischemic zone. However, CDAs in the transition zone around the necrosis were significantly increased in the venular capillary portion in the subendocardium and in all capillary portions in the subepicardium compared with those in the non-ischemic zone. Immunohistological staining for basic fibroblast growth factor (bFGF) revealed punctate bFGF distribution in both the non-ischemic and transition zones of ventricular tissues 30 days after occlusion, suggesting a persistent stimulation for capillary angiogenesis. CONCLUSION: The remodelling of the capillary bed is not uniform throughout the cardiac tissue in coronary-occluded rat hearts. CDAs decreased in the non-ischemic zone but increased in the transition zone. The rate of capillary angiogenesis failed to parallel the development of hypertrophy in the transition zone over 30 days, as could be seen from the significant reduction in the percentage of venular capillary portions.

Animals↗

PubMed1998

Increased fiber capillarization in flight muscle of finch at altitude.

We examined fiber capillarization and ultrastructure in the highly aerobic flight muscle of six gray crowned rosy finches (Leucosticte arctoa; mass 22.9 +/- 0.5 (SE) g) living at altitude (A; White Mountains of Eastern California; 4000 m) compared to eight sea-level (SL) house finches (Carpodacus mexicanus, mass, 19.8 +/- 0.6 g) of the same subfamily, Carduelinae. Capillary length per fiber volume (A, 10,400 +/- 409 mm(-2); SL, 7513 +/- 423; P < 0.001) and capillary-to-fiber ratio (A, 2.32 +/- 0.07; SL, 1.85 +/- 0.06; P < 0.001) were significantly greater in A, with no difference in fiber cross-sectional area compared to SL. Capillary geometry was significantly different in A, yielding a greater contribution of tortuosity and branching to capillary length than in SL. Capillary-to-fiber surface ratio and fiber mitochondrial volume were both greater in A, but their ratio was similar to SL, indicating a proportional increase in the size of the capillary to fiber interface and fiber mitochondrial volume in A to sustain high levels of aerobic capacity while living at altitude.

Adaptation, Physiological↗

PubMed1987

Kupffer cell depletion associated with capillarization of liver sinusoids in carbon tetrachloride-induced rat liver cirrhosis.

Rats were made cirrhotic by carbon tetrachloride inhalation associated with phenobarbital in the drinking water over 10 weeks. After a 1-week recovery period a 99mTc sulphur colloid radioisotope scan of the liver was carried out on each animal following bolus injection into the iliac vein. Kupffer cells were then histologically identified by one of three methods: colloidal carbon uptake, iron staining after ferritin-dextran, or endogenous peroxidase staining. The degree of liver injury was classified into four pathological groups and these were correlated with the phagocytic capacity of each liver as recorded on the isotope scan. All three histological markers demonstrated that in normal liver, Kupffer cells are more plentiful in periportal areas. In cirrhotic liver, there were very few Kupffer cells in nodular regenerative areas, where continuous capillaries are found, but Kupffer cells were present in the remaining more normal trabecular-sinusoidal areas. Morphometric counting of carbon- and ferritin-labelled Kupffer cells demonstrated a significant decrease in cirrhotic livers. A close correlation was also found between increasing degree of liver injury and diminished hepatic phagocytic capacity, as demonstrated by the radioisotope scan. The study demonstrates that where regenerative liver is capillarized, with replacement of fenestrated sinusoids, Kupffer cells are absent.

Animals↗

PubMed1992

Anti-myeloperoxidase autoantibodies in patients with necrotizing glomerular and alveolar capillaritis.

We conducted a prospective study of 651 Mediterranean patients from Catalonia (Spain) with well-defined forms of systemic vasculitis, connective tissue diseases, and renal and pulmonary disorders to determine the prevalence and clinical value of antineutrophil cytoplasmic autoantibodies (ANCA) with myeloperoxidase (MPO) specificity (MPO-ANCA). ANCA were first tested by indirect immunofluorescence on ethanol-fixed neutrophils. When a positive result was obtained, then MPO-ANCA were identified by performing the immunofluorescence assay again on neutrophils from a voluntary donor known to have a complete and selective deficiency of MPO. This disorder was detected by automated flow cytochemistry with the Technicon system and was further verified by cytochemical and biochemical studies. We detected MPO-ANCA in 61 of 70 (87%) patients with a perinuclear pattern (p-ANCA), but in none of 25 with a cytoplasmic pattern (c-ANCA). These results were corroborated by enzyme-linked immunosorbent assay (ELISA) using human purified MPO as a substrate. On immunofluorescence microscopy, all patients with MPO-ANCA were found to have a typical and restrictive immunostaining pattern. In our study, while c-ANCA were mainly found in patients with biopsy-proven Wegener's granulomatosis, MPO-ANCA identified those with idiopathic and polyarteritis nodosa-associated necrotizing and crescentic glomerulonephritis. In addition, pulmonary hemorrhage with necrotizing alveolar capillaritis as the main morphologic substrate occurred frequently among patients with MPO-ANCA, including three affected by polyarteritis nodosa and three who had pulmonary hemorrhage as the only clinical finding. On the other hand, these antibodies could be also detected in 30% of patients with a proven diagnosis of anti-glomerular basement membrane (GBM) disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Antineutrophil Cytoplasmic↗

PubMed2005

Passive microfluidic control of two merging streams by capillarity and relative flow resistance.

In the progress of microfluidic devices, a simple and precise control of multiple streams has been essential for complex microfluidic networks. Consequently, microfluidic devices, which have a simple structure, typically use external energy sources to control the multiple streams. Here, we propose a pure passive scheme that uses capillarity without using external force or external regulation to control the merging of two streams and even to regulate their volumetric flow rate (VFR). We accomplish this process by controlling the geometry of two inlets and a junction, and by regulating the hydrophilicity of a substrate. Additionally, we use the relative flow resistance to control the VFR ratio of the merged two streams. Our results will significantly simplify the control of multiple streams without sacrificing precision.

Capillary Action↗

PubMed2003

Capillarity effects on crystallization kinetics: insulin.

During layerwise growth of crystals, capillarity governs the generation of new crystal layers. Theory predicts that the line tension of the layer edge determines, via the characteristic two-dimensional capillary length L(c), the rates of generation and initial growth of the new layers. To test the correlation between L(c) and the rate of layer generation, we used in situ Tapping Mode Atomic Force Microscopy (TM-AFM) to study the generation and spreading of layers during crystallization of rhombohedral, R3, porcine insulin. We show that crystallization of this insulin form is uniquely suitable for such an investigation due to the linear kinetics of step growth it exhibits. This linear kinetics reflects the abundance of the incorporation sites along the rough steps, the lack of long-range step-step interactions, and the transport control of the growth kinetics. The kinetic coefficients are 7 x 10(-)(3) and 4 x 10(-)(2) cm s(-)(1), respectively, in the absence and presence of the cosolvent acetone-somewhat high for proteins and comparable to values for inorganic systems. We show that (i). the relevant capillary length, the size of a critical quadrangular 2D nucleus L(c), is the main scaling factor for the density of growth steps, while (ii). all steps longer than L(c) grow with a rate determined only by the supersaturation and independent of their length. We explain the divergence of (ii). from theoretical predictions with the high supersaturations typical of the growth of this protein system.

Crystallization↗

PubMed2004

Skeletal muscle morphology and capillarization of renal failure patients receiving different dialysis therapies.

The morphology of gastrocnemius muscles was examined in RFPs (renal failure patients) being treated using HD (haemodialysis) and CAPD (continuous ambulatory peritoneal dialysis). RFPs (n=24) volunteered to participate in the present study. Twelve RFPs (five women and seven men; mean age, 55 years) were undergoing CAPD treatment and 12 RFPs (two women and ten men; mean age, 62 years) were undergoing HD treatment. Muscle biopsies from gastrocnemius muscles were found not to differ (P>0.05) in fibre type distribution, MyHC (myosin heavy chain) expression or fibre CSA (cross-sectional area) between the two groups. There were, however, significant differences (P<0.05) in CC/F (capillary contact/fibre), C/F (capillary to fibre ratio) and cytochrome c oxidase activity. The HD group had 33% more CC/F, with a 19% higher C/F and 33% greater cytochrome c activity in glycolytic fibres (II) than the CAPD group. There were no apparent differences in age, gender, co-morbidity, self-reported physical activity or physical functioning between the two groups, which could account for the difference in muscle capillarity between the groups. The HD patients were, however, administered heparin as a routine part of the dialysis therapy. The possibility is discussed that heparin in combination with mild anaemia and acidosis may have augmented angiogenesis in the HD patients.

Adult↗

PubMed1997

The capillarity of the subendocardium of left ventricle in rats reared at a low temperature for many generations.

The cardiac capillarity in adult rats reared at 5 degrees C for 68 generations was studied with a double staining method of alkaline phosphatase and dipeptidylpeptidase IV. Capillary density, proportions of arteriolar, intermediate and venular capillary portions and capillary domain area were measured in the left ventricular wall. Compared with the control rats which had been brought back from the low temperature at the 12th generation and reared at 25 degrees C since then, the heart and the cardiac cells were hypertrophied, total capillary density increased and the capillary domain areas were reduced along the capillary path from the arteriolar to venular capillary portions. The number of the venular capillary portions showed no significant change but the arteriolar and intermediate capillary portions significantly increased. All these changes suggest that the cardiac capillary network was better developed in the cold-reared rats than in control rats. In the cold-adapted rats the hypertrophic changes in cardiac cells are thus accompanied by improvements in the oxygen delivery capacity. This adaptation provides a basis for the maintenance of increased thermogenesis in many organs. The changes cannot be established by several weeks exposure to low temperature, but only after rats have been bred in a cold room for generations.

Adaptation, Physiological↗

PubMed1999

Pulmonary capillaritis associated with the antiphospholipid antibody syndrome and rapid response to plasmapheresis.

OBJECTIVE: Pulmonary capillaritis is an uncommon complication of antiphospholipid antibody syndrome but has important therapeutic implications. CASE REPORT: A patient with antiphospholipid antibody syndrome presented with haemoptysis and respiratory failure. Investigation including open lung biopsy, demonstrated vasculitis as the underlying pathology, rather than thrombosis. The patient responded promptly to methylprednisolone, cyclophosphamide and plasmapheresis. CONCLUSION: Plasmapheresis has not previously been described in this setting and the rapid response suggests that it should be considered in severe disease.

Antiphospholipid Syndrome↗

PubMed2004

Extended version of the van der Waals capillarity theory.

An extended version of the van der Waals capillarity theory describing the liquid-vapor interface in the temperature range from the triple to the critical point is suggested. A model functional of thermodynamic potential for a two-phase Lennard-Jones system taking into account the effect of the highest degree terms of gradient expansion has been constructed. The identity of the thermodynamic and the mechanical definition of Tolman's length has been proved in the framework of the adopted form of functional. The properties of nuclei of the liquid and the vapor phase are described. The paper determines: the work of formation of a nucleus, density profiles, size dependences of the surface tension, and the parameter delta in the Gibbs-Tolman-Koenig-Buff equation.

Journal Article↗

PubMed2000

Capillaritis associated with interferon-alfa treatment of chronic hepatitis C infection.

We report the case of a 36-year-old man who was referred with an asymptomatic eruption that started on both lower legs. This started shortly after being commenced on interferon-alfa for chronic hepatitis secondary to hepatitis C. Clinically, the eruption was consistent with a capillaritis (pigmented purpuric dermatosis). Histology confirmed this to be lymphocytic vasculitis. Lymphocytic vasculitis is frequently identified in the salivary glands of patients who are hepatitis C positive. Although leukocytoclastic vasculitis confined to the skin is frequently reported with hepatitis C, lymphocytic vasculitis is rarely reported. We consider that the lymphocytic vasculitis in our patient occurred as a result of interferon-alfa treatment because of the strong temporal relationship between the onset of the skin eruption and drug therapy.

Adult↗

PubMed1998

Churg-Strauss syndrome presenting with pulmonary capillaritis and diffuse alveolar hemorrhage.

Churg-Strauss syndrome (CSS) is a rare disorder characterized by the histopathological triad of systemic necrotizing vasculitis, extravascular granuloma, and eosinophilic infiltrate, occurring in individuals with asthma or a history of allergy. We report a case of CSS with rare presentation of diffuse pulmonary hemorrhage. A transbronchial lung biopsy showed necrotizing vasculitis, pulmonary capillaritis, and prominent eosinophilic infiltrate. At autopsy, necrotizing granuloma and diffuse alveolar hemorrhage were found in the lungs. Laboratory data showed hypereosinophilia, disseminated intravascular coagulopathy, and positive anti-proteinase 3 antineutrophil cytoplasmic antibody (ANCA). This case emphasize that CSS should be considered in the differential diagnosis of ANCA-positive vasculitis with diffuse alveolar hemorrhage.

Adult↗

PubMed2006

delta-Lactone from Oedogonium capillare and their effects on rat ileum.

Antispasmodic activity-guided fractionation together with chemical analysis led to the isolation of one novel delta-lactone named oedogonolide from Oedogonium capillare. Identification was based on spectroscopic methods. The oedogonolide produces a significant antispasmodic effect on the contractions of the rat ileum induced by acetylcholine, histamine and barium chloride.

Animals↗

PubMedDate not supplied

Capillarity and fibre types in locomotory muscles of wild yellow-legged gulls (Larus cachinnans).

This study analyzes the capillarity and fibre-type distribution of six locomotory muscles of gulls. The morphological basis and the oxygen supply characteristics of the skeletal muscle of a species with a marked pattern of gliding flight are established, thus contributing to a better understanding of the physiology of a kind of flight with low energetic requirements. The four wing muscles studied (scapulotriceps, pectoralis, scapulohumeralis, and extensor metacarpi) exhibited higher percentages of fast oxidative glycolytic fibres (>70%) and lower percentages of slow oxidative fibres (<16%) than the muscles involved in nonflight locomotion (gastrocnemius and iliotibialis). Capillary densities ranged from 816 to 1,233 capillaries mm(-2), having the highest value in the pectoralis. In this muscle, the fast oxidative glycolytic fibres had moderate staining for succinate dehydrogenase and relatively large fibre sizes, as deduced from the low fibre densities (589-665 fibres mm(-2)). All these findings are seen as an adaptive response for gliding, when the wing is held outstretched by isometric contractions. The leg muscles studied included a considerable population of slow oxidative fibres (>14% in many regions), which suggests that they are adapted to postural activities. Regional variations in the relative distributions of fibre types in muscle gastrocnemius may reflect different functional demands placed on this muscle during terrestrial and aquatic locomotion. The predominance of oxidative fibres and capillary densities under 1,000 capillaries mm(-2) in leg muscles is probably a consequence of an adaptation for slow swimming and maintenance of the posture on land rather than for other locomotory capabilities, such as endurance or sprint activities.

Animals↗

PubMed2001

Muscle adaptation to altitude: tissue capillarity and capacity for aerobic metabolism.

Prolonged exposure to high altitude leads to reduced muscle mass and performance. The fall in muscle mass follows a reduction in fiber size, which at first was believed to be accompanied by increased fiber capillarization and aerobic enzymes. Subsequent studies showed that hypoxia alone does not alter capillary number and geometry in skeletal muscles of mammals at altitude. It was also found that alterations in fiber size and aerobic enzymes depend on a number of additional factors, including animal activity and the level of hypoxia (e.g., moderate vs. extreme altitude). With training at altitude, fiber capillary number and aerobic enzymes are increased, indicating that muscle potential for plasticity is conserved in hypoxia. Recent studies have also shown that capillary number and geometry are altered in muscles of several species of birds native or exposed to higher altitude; that is, that capillary growth can occur in skeletal muscle in response to chronic exposure to high altitude. In this mini review, we summarize these data and current knowledge on muscle capillary to fiber structural relationships and their implications for muscle aerobic function at altitude.

Adaptation, Physiological↗