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Results for “CAPILLARITY”

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At least 109 records · Page 6Linked to original sources

PubMed1998

Pulmonary capillaritis: a possible histologic form of acute pulmonary allograft rejection.

Acute rejection after lung transplantation occurs commonly and is usually characterized histologically by a perivascular mononuclear infiltrate. We report five cases of pulmonary capillaritis with a histologic appearance distinct from typical rejection, occurring in patients ranging in age from 18 to 45 years, with a variety of underlying diseases including alpha1 antitrypsin deficiency, pulmonary hypertension, cystic fibrosis, and rheumatoid arthritis. Four of the five patients had alveolar hemorrhage histologically, and two had frank hemoptysis. Time of onset ranged from 3 weeks to many months after transplantation. Three cases were fulminant, and there were two deaths. In only one case, with methicillin-resistant Staphylococcus aureus bronchitis, could infection be established. All were treated with intensification of immunosuppressive therapy. Plasmapheresis was carried out in two cases and coincided with temporary improvement, but its efficacy was questionable because of concurrent immunosuppressive therapy. Two had recurrent biopsy-proven acute rejection within 6 weeks of treatment, and one had recurrent severe pulmonary hemorrhage that abated with total lymphoid irradiation. Our experience suggests that pulmonary capillaritis in lung transplant recipients can be an acute, fatal illness with the potential for recurrence in the survivors. We speculate that it represents a form of acute vascular rejection. Early pathologic diagnosis and aggressive immunosuppressive therapy are recommended. Although a humoral component was not documented, the possible response to plasmapheresis requires continued evaluation.

Acute Disease↗

PubMed1996

Lipid peroxides production after strenuous exercise and in relation to muscle morphology and capillarization.

The antioxidative capacity of slow twitch muscle fibers has been reported to be higher than that of fast twitch ones. The purpose of this study was to relate the production of lipid peroxides during exercise to the morphology and capillarization of human muscles. Twenty-seven healthy volunteers performed a strenuous 90-min exercise. The content of malonyldialdehyde (MDA) in the middle portion of vastus lateralis muscle was found positively correlated with percentage and the relative cross-sectional area of the type 1 of muscle fibers (r = 0.46, P < 0.05, r = 0.43, P < 0.05, respectively) but negatively with type II muscle fibers (r = -0.46, P < 0.05, r = -0.43, P < 0.05, respectively), especially type IIB. The content of MDA in the vastus lateralis muscle correlated positively with the number of capillaries around type II muscle fibers (r = 0.71, P < 0.001). It is suggested that the production of lipid peroxides parallels the exercise-induced increase of oxygen uptake in the muscle, being highest in more oxidative and better perfused, oxygen-consuming muscle fibers.

Adult↗

PubMed1995

A patient with antineutrophil cytoplasmic antibody-negative pulmonary capillaritis and circulating primed neutrophils.

We describe an antineutrophil cytoplasmic antibody-negative patient with capillaritis, acute respiratory failure, and primed neutrophils circulating systemically. Thoracoscopic lung biopsy showed capillary destruction, with neutrophils infiltrating the lung interstitium and air spaces but no alveolar damage or hemorrhage. We suggest that this atypical, limited form of pulmonary injury may occur when circulating neutrophils are primed, but, in the absence of an activating factor, not fully activated.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1988

Immobilized pH gradients in ultrathin-layer (100 micron) gels: avoiding capillarity by a 'squeezing-sealing mold' technique.

Several procedures for casting 100 microns ultrathin immobilized pH gradients are described. When acrylate/glass molding cassettes (Pascali et al., Electrophoresis 1987, 8, 371-373) are used two main problems are encountered: (i) a tendency of polymerization solutions, at the beginning of delivery, to spread across the glass surfaces with troublesome effects on the gradient stratification, and (ii) the raising of steep menisci at both extremities of the pH intervals, originating from capillarity phenomena and resulting in nonuniform gradients with bowed electrophoretic patterns. The first shortcoming was acceptably solved by increasing the density of sucrose gradients, and pouring them into prewarmed molding cassettes. The detrimental effect of menisci could be overcome by using a 'squeezing-sealing mold' technique. A molding cassette was endowed with a continuous, squared spacer frame, the upper side being open by inserting a wedged clip. A slight excess of polymerization solution was first dispensed into the cassette and squeezed away on removal of the clip. By completely excluding air from the molding cassette, uniform and well reproducible ultrathin gels could be cast. A major advantage of ultrathin immobilized pH gradient gels is the drastically shorter focusing time.

Blood Proteins↗

PubMed2002

Biopsy sampling requirements for the estimation of muscle capillarization.

The aim of this study was to determine the number of tibialis anterior biopsy samples and muscle fibers required to estimate the capillary supply of individual muscle fibers (C:F(i)). C:F(i) was calculated for 25 type 1 fibers in each of 8 images from 3 biopsies of 5 young healthy individuals. Sequential estimation analysis indicated that 50 fibers from one biopsy are sufficient to characterize the C:F(i) of the tibialis anterior for a group of subjects. Thus, when analyzing the capillarization of the tibialis anterior, the requirements of only one biopsy sample and 50 fibers means a great reduction in time for analysis and in the invasiveness of the procedure.

Adult↗

PubMed2003

Capillarization and vascular endothelial growth factor expression in hypertrophying anterior latissimus dorsi muscle of the Japanese quail.

Hypertrophy may increase the diffusion distances from capillaries to the interior of the muscle fibers. We hypothesized that capillary proliferation occurs during hypertrophy, which is accompanied by an up-regulation of vascular endothelial growth factor (VEGF). Hypertrophy of the left anterior latissimus dorsi muscle of Japanese quail (2-3 months old) was induced by 1-4 week stretch-overload. Capillarization was analyzed in cross-sections stained for ATPase. VEGF expression was determined with RT-PCR. Initially, hypertrophy was not accompanied by increases in fiber cross-sectional area (FCSA), but after 1 week the average FCSA did increase. The capillary to fiber ratio was decreased after 1 week, but returned to control values in subsequent weeks. This indicates that capillary proliferation occurred, because this model is characterized by extensive fiber proliferation. The absence of any significant change in VEGF mRNA levels indicates that increased levels of VEGF mRNA are not crucial for capillary proliferation during muscle hypertrophy.

Animals↗

PubMed1976

Subsarcolemmal mitochondria and capillarization of soleus muscle fibers in young rats subjected to an endurance training. A morphometric study of semithin sections.

Rats, 6 weeks old, were subjected to a program of endurance running for 3, 6 and 12 weeks. 0.5 to 0.8 mum thick sections of Epon embedded soleus muscles were studied with morphometric methods. In cross-sections the area occupied by subsarcolemmal mitochondria was independent of the age, but was 53% higher after 12 weeks of training. The mean depth of the zones with subsarcolemmal mitochondria increased only 15% to about 0.9 mum. Thus, the subsarcolemmal mitochondria showed a pronounced spreading at the muscle fiber surface in trained muscles.-The number of capillaries per fiber decreased slightly in controls and increased not significantly in trained muscles. It is concluded that the subsarcolemmal mitochondria supply the energy for the active transport of metabolites through the sarcolemma in oxidative muscle fibers, and that they are the limiting factor for endurance performance of the soleus muscle fibers because the changes in the capillarization were only small. It is suggested that the subsarcolemmal and the interfibrillar mitochondria have different functions and may therefore represent different types of mitochondria which can be distinguished by their morphology as well as by their biochemical properties.

Animals↗

PubMed1993

High altitude tissue adaptation in Andean coots: capillarity, fibre area, fibre type and enzymatic activities of skeletal muscle.

Capillarity, fibre types, fibre area and enzyme activities of different skeletal muscles (pectoralis, extensor digitorum longus), tibialis anterior, plantaris and the myocardium) were compared in Andean coot (Fulica americana peruviana) native to high altitude (Junín, Perú, 4200 m) and the same species nesting at sea level. Numbers of capillaries per square millimeter were higher in all high-altitude muscles when compared with sea-level muscles (P < 0.0001). Moreover, values for capillaries per fibre and capillaries in contact with each fibre were higher in digitorum and tibialis high-altitude muscles. Muscle fibres were classified as Type I, Type IIA or Type IIB on the basis of their myofibrillar ATPase pH lability. Pectoralis muscle of high-altitude and sea-level coots presented only fibres of Type IIA. In contrast, all the leg muscles studied showed a mosaic pattern of the three fibre types. Fibre areas were determined using a Leitz Texture Analysis System. Significant differences in fibre area were observed (P < 0.01) between high-altitude and sea-level muscles. Mean muscle fibre diameters were also lower in the high-altitude group than in the sea-level group. The enzyme activities studied were hexokinase, lactate dehydrogenase, citrate synthase and 3-hydroxyacyl-CoA-dehydrogenase. The oxidative capacity, as reflected by citrate synthetase and hydroxyacyl-CoA-dehydrogenase activities, was greater for myocardial and pectoralis than for leg muscles. However, analysis of maximal enzyme activities showed that there were no significant differences between the glycolytic and oxidative enzyme activities of high-altitude and sea-level coots.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗

PubMed1993

Contrasting effects of treatment with omega-3 and omega-6 essential fatty acids on peripheral nerve function and capillarization in streptozotocin-diabetic rats.

Essential fatty acid metabolism is impaired by diabetes mellitus and this may be important in the aetiology of peripheral nerve dysfunction. The effects of gamma-linolenic acid (omega-6) and fish oil (omega-3) alone, and in combination, on nerve function and capillarization were examined in 2-month streptozotocin-diabetic rats. Diabetes resulted in approximately 15% and 23% decreases in saphenous sensory and sciatic motor nerve conduction velocities, respectively (p < 0.001). Motor and sensory conduction velocities were in the non-diabetic range after both preventive and reversal omega-6 treatment of diabetic rats (p < 0.001). No significant changes occurred in omega-6 treated non-diabetic rats. Preventive omega-3 treatment was largely ineffective. Reversal treatment with a combination of omega-6 and omega-3 fatty acids was marginally effective and improved motor (p < 0.05), but not sensory conduction velocity. In vitro measurement of sciatic nerve resistance to hypoxic conduction failure in diabetic rats revealed a 56% increase in the time taken for the compound action potential amplitude to be reduced by 80% (p < 0.01) compared to non-diabetic rats. This was partially prevented by omega-6 treatment (29% increase, p < 0.01). Reversal omega-6 treatment had a lesser effect (37% increase, p < 0.05 compared to untreated diabetic rats). omega-3 treatment had no significant effect on conduction failure time. Sciatic endoneurial capillary density increased by 11% with preventive omega-6 treatment (p < 0.05), but was unaffected by reversal omega-6 and by omega-3 treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1985

Effect of growth on muscle capillarity and fiber type composition in rat diaphragm.

The effect of growth on the capillarity and fiber type composition of the diaphragm, soleus and extensor digitorum longus (EDL) muscles of rats weighing between 55 and 330 g have been studied. Muscle samples obtained from the anesthetized rat were rapidly frozen and sliced transversely in a cryostat. The sections were stained histochemically by the SDH method and the myosin ATPase method after preincubation at pH 4.3 to typify fibers (FG, FOG and SO fibers). To visualize capillaries, the myosin ATPase method after preincubation at pH 4.0 was used. The percentage of FOG fibers decreased in all muscles with growth. While the FG and SO fibers increased in the diaphragm, SO fibers increased in the soleus, and FG fibers increased in the EDL. The capillary density showed a hyperbolic decrease with growth in all muscles, while the number of capillaries around each fiber increased in all muscles with growth. It is concluded that growth causes the changing properties of the motoneurons and the new capillary formation in the diaphragm muscle, as well as the soleus and EDL muscles.

Animals↗

PubMed1979

Changes in the capillarity of skeletal muscle in the growing rat.

Capillary density (CD), capillary to fiber ratio (C/F), fiber cross sectional area (FCSA) and fiber composition were measured in the soleus and the gastrocnemius (medial head) muscles of rats weighing between 99 and 666 g. Muscle samples obtained from the anesthetized animal were rapidly frozen (-130 degrees C) sliced transversely at 16--18 micrometers, and treated histochemically by the ATPase method after preincubation at pH's of 4.0 and 4.4 to visualize capillaries and typify fibers. In both muscles the FCSA was positively related to body weight (BW) and muscle weight. At a given BW, the FCSA of the soleus was greater than that of the gastrocnemius. In both muscles CD decreased hyperbolically with FCSA (soleus: CD = 1.0613 X 10(6)/FCSA + 298.71; gastrocnemium: CD = 1.0349 X 10(6)/FCSA + 240.74). At the same time a positive linear correlation between C/F and FCSA was found (soleus: C/F = 3.92 X 10(-4) FCSA + 0.82; gastrocnemius: C/F = 2.90 X 10(-4) FCSA + 0.93). At a given FCSA, CD and C/F were greater in the soleus than in the gastrocnemius because of differences in fiber composition between the two muscles. The soleus had only oxidative fibers (STO and FTOG) whereas the gastrocnemius had 54% glycolytic fibers (FTG). The very large variability in CD and C/F values reported in the literature could, in part, be due to the differences in capillarity observed with maturation. A change in fiber composition with BW was observed in the soleus, but no systematic change occurred in the gastrocnemius.

Adenosine Triphosphatases↗

PubMed1985

Myocardial capillarity in acclimation to hypoxia.

Capillarity, O2 diffusion distances and fiber cross-sectional growth were measured in the hearts of guinea pigs exposed early during growth to hypobaric hypoxia (PB = 430 torr, PO2 = 90 torr). Twelve 5-week old males were maintained in a hypobaric chamber for 4-14 weeks. Their hearts were perfusion-fixed via the aorta with a 2.5% glutaraldehyde, 1% formaldehyde buffered solution; blocks were cut from left (LV) and right (RV) ventricles, post-fixed in OsO4, dehydrated and embedded in Spurr medium. Blocks were cut transversely to fiber orientation, 0.5 micron thick, stained with Toluidine Blue, and photographed at 400 X. Number and location of capillaries and fiber cross-sectional areas (FCSA) were scored from these photographs and from those of normoxic controls. Growth rates were similar for control and hypoxic guinea pigs. As animals grew, LV and RV weights increased linearly with body weight. Hypoxic guinea pigs had LV weights similar to controls but the RV showed varying degrees of hypertrophy. Control and hypoxic guinea pigs showed similar linear increases in FCSA with ventricular weight, suggesting that hypertrophy was due to increased FCSA. Capillary density (CD) decreased and capillary-to-fiber ratio (C:F) increased with FCSA, and O2 diffusion distances lengthened in LV and RV of animals in both groups. CD and C:F were higher and O2 diffusion distances were shorter in most hypoxic animals compared to controls. When RV hypertrophy was large (RV greater than 0.7 g) and failure imminent, CD, C:F and O2 diffusion distances were similar to controls suggesting that in these hearts oxygenation was impaired.

Acclimatization↗

PubMed1992

Adaptations in skeletal muscle capillarity following changes in oxygen supply and changes in oxygen demands.

The effects of changes in oxygen supply and oxygen demands on fiber cross-sectional areas, capillary densities and capillary to fiber ratios were determined in three skeletal muscles of rat. The muscles examined were the vastus lateralis, soleus, and diaphragm. Reduced oxygen supply was produced by subjecting rats to ambient hypoxia, and increased oxygen demands were produced by subjecting rats to low ambient temperatures or treatment with thyroxin. Capillaries were visualized by injecting fluorescent dyes into the circulation. Muscles were quick frozen at resting lengths to preserve normal fiber geometry and were subsequently sectioned on a cryostat. All of the muscles sampled from animals in the experimental groups had elevated capillary densities. However, capillary to fiber ratios were not increased significantly in any muscle, for any experimental condition. Thus, all of the observed differences in capillarity were due to changes in the intrinsic rate of muscle fiber growth. Further, the relations of capillary density and capillary to fiber ratio to fiber area were the same as those obtained during normal maturation, suggesting that capillary growth is closely linked to the intrinsic rate of fiber growth.

Adaptation, Physiological↗

PubMed1993

Capillaritis: a manifestation of rheumatoid disease.

We present seven cases of capillaritis arising in patients with rheumatoid arthritis and suggest that it is primarily related to disease activity and not drugs. In the majority, the rash resolved spontaneously with the use of a topical steroid to treat the symptom of itch.

Administration, Topical↗

PubMed1993

Metabolic capacity, fibre type area and capillarization of rat plantaris muscle. Effects of age, overload and training and relationship with fatigue resistance.

1. The influences of age (5, 13 and 25-month-old rats), overload as obtained by denervation of synergists, and training on the metabolic capacity, relative muscle cross-sectional area occupied by each fibre type, capillarization and fatigue resistance of the rat m. plantaris were investigated. 2. Creatine kinase, phosphorylase and citrate synthase activities were lower in muscles of 25 than in those of 13-month-old rats (P < 0.001). 3. Overload resulted in an increased relative area of type I and IIa fibres at all ages (P = 0.001). 4. Capillary density decreased with overload and increasing age (P < 0.001). 5. Fatigue resistance was higher in muscles of 13 than in those of 5-month-old rats (P < 0.05), and increased with overload (P < 0.05) at all ages. 6. Fatigue resistance of the whole muscle was not closely related to its oxidative capacity in contrast to what is generally found for single fibres or motor units.

Aging↗

PubMed1984

Effects of maturation on tissue capillarity in chickens.

Tissue capillarity, diffusion distances and myoglobin concentrations in the anterior latissimus dorsi (ALD), consisting entirely of slow tonic fibers, the posterior latissimus dorsi (PLD), consisting entirely of twitch fibers, and the gastrocnemius (GST), consisting of both twitch and tonic fibers, were determined for the domestic chicken throughout maturation. Increases in muscle mass for the three muscles are due to fiber hypertrophy and are quantified as changes in the average cross-sectional area (FCSA) of the fibers. Capillary densities were highest in the newly hatched chicks: ALD = 3967 +/- 888 caps/mm2, PLD = 8360 +/- 1078 caps/mm2, and GST = 8360 +/- 8360 +/- 1283 caps/mm2; and decreased in proportion to the increase in FCSA, to adult values of ALD = 450 +/- 50, PLD = 120 +/- 20 and GST = 267 +/- 33 caps/mm2. In contrast to mammals, the ratio of the numbers of capillaries to the numbers of muscle fibers appears to be fixed at or shortly after hatch; there is not an increase in the numbers of capillaries to offset fiber hypertrophy. Consistent with the observations on capillary densities, the diffusion distances are shortest in the newly hatched chicks where the maximal diffusion distance is 17.9 +/- 1.06 micron in the ALD, 12.5 +/- 1.08 micron in the PLD and 17.4 +/- 0.93 micron in the GST. The maximal diffusion distance increased in proportion to FCSA; to 42.4 +/- 5.75 micron in the ALD, 88.8 +/- 1.33 micron in the PLD and 64.4 micron +/- 8.59 micron in the GST. In the adult the diffusion distances varied with the fiber type of the muscle. Myoglobin concentrations were similar in the ALD and PLD and were lowest at hatch but increased to plateau values of 4.3 +/- 0.51 mg/g for the slow-tonic ALD and 2.2 +/- 0.33 mg/g for the fast-twitch PLD. In contrast, myoglobin concentrations in the GST were highest in the newly hatched chicks and decreased to a low-level plateau of 1.8 +/- 0.83 mg/g in the adult. The very high myoglobin concentrations in the GST of the newly hatched chicks may represent an adaptation to conditions of extreme hypoxia in the hind limb of the developing embryo.

Animals↗

PubMed1985

Effects of hypoxia on muscle capillarity in rats.

Capillary density, fiber cross-sectional area, capillary/fiber ratio and fiber composition were determined in gastrocnemius and diaphragm muscles of laboratory rats following five weeks at 350 Torr ambient pressure. Growth rates of hypoxic rats were lower than normoxic controls, but the periods of sacrifice were adjusted to achieve similar body masses for the two groups. Hypoxic rats had significantly higher hematocrits and heart masses, characteristic of acclimation to hypoxia. However, capillary/fiber ratios in gastrocnemius and diaphragm were similar for hypoxic and normoxic rats suggesting that hypoxia did not stimulate capillarity in either muscle. In diaphragm, but not gastrocnemius, diffusion distances were significantly shorter in hypoxic rats than in controls. We conclude that the differences in diffusion distances represent an important secondary effect of hypoxia on the diaphragm associated with changes in demands on ventilation in response to low oxygen pressures.

Animals↗

PubMed1988

Muscle capillarity in rats with increased blood oxygen affinity.

To investigate the effects of low P50Hb on muscle capillarity, rats were injected with Na-cyanate (50 mg/kg BW) every day for 2 or 4 weeks (experimental). Controls received injections of saline. After 2 weeks P50 was reduced in the experimental animals (20.4 vs 30.3 Torr). After 4 weeks experimental animals showed a 13% increase in hematocrit and Hb. PVO2 was lower in experimental than in control rats (28.3 +/- 1.0 vs 33.8 +/- 4.7 mm Hg). Fiber cross-sectional area (FCSA), capillary density (CD) and capillary-to-fiber ratio (C/F) were measured in sections treated with the ATPase technique. FCSA was smaller in experimental than in controls (3000 +/- 491 vs 4121 +/- 415 micron 2 for the soleus and 3633 +/- 236 vs 4251 +/- 194 micron 2 for the gastrocnemius) and CD was higher (729 +/- 99 vs 578 +/- 75 cap/mm2 in the soleus and 388 +/- 19 vs 323 +/- 14 cap/mm2 in the gastrocnemius) but C/F was not different. Diffusion distances for O2 measured by the closest individual method were not significantly different between the two groups. The higher CD in the experimental animals seems to be the result of their smaller FCSA and not the result of capillary proliferation. The volume of tissue served by a capillary was significantly reduced in the experimental animals. This could help the transfer of O2 to the muscle in animals with a low P50 Hb.

Animals↗