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Results for “Capillary Fragility”

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At least 469 records · Page 26Linked to original sources
PubMed1977

Haemodynamic and respiratory changes accompanying haemorrhagic shock in thoracotomized dogs.

Haemorrhagic shock was induced after thoracotomy by bleeding into a reservoir and the reduction of systemic blood pressure to 40 mm Hg. After two hours the blood was retransfused. The haemodynamic and respiratory changes due to the haemorrhage and retransfusion were noted during the two hour shock period and one hour after transfusion. The results were as follows: 1. Pulmonary mean and systemic mean pressure during haemorrhage and retransfusion do not change in parallel; 2. there is a rapid rise in pulmonary arterial [PA] and pulmonary capillary [PC] pressure during retransfusion; 3. cardiac output and its pulmonary fraction decrease during shock and cardiac output failed to normalise on retransfusion of the lost blood; 4. pulmonary vascular resistance, pulmonary total resistance increase significantly at the end of the shock period and after retransfusion; 5. shunt volume, alveolo-arterial O2 difference, the difference in arterio-alveolar co2 tension and dead space ventilation increase; while 6. o2 consumption and CO2 production decrease; 7. arterial blood gas values alone do not indicate those serious metabolic; circulatory and respiratory changes which develop in the lung during shock; 8. effective pulmonary compliance and the plasma oncotic pressure decrease, indicating interstitial oedema; 9. the primary mechanism responsible for the disorder during shock is not entirely clear but beside a number of other factors, the importance of the hypoperfusion of the bronchial circulation is stressed; 10. the conclusions permit a certain insight into the pathogenesis and therapeutic possibilities of the adult respiratory distress syndrome.

Animals↗
PubMed1984

[Sclerodermal microangiopathy: a cause or a consequence?].

Microangiopathy is an essential clinicopathological feature of systemic scleroderma, comprising capillary thinning, thickening of the basement membrane and abnormalities of the endothelium which has an abnormally high uptake of radioactive thymidine. The identification of a circulating cytotoxic factor for endothelial cells suggests that the microangiopathy may play a role in the physiopathogenesis of the disease. In practice, microangiopathy can be fully assessed by capillaroscopy in patients with systemic scleroderma.

Capillaries↗
PubMed1975

Xanthinol nicotinate in peripheral vascular disease.

In a double-blind control of xanthinol nicotinate ('Complamin'; 'Complamex') in patients with severe progressive obliterative vascular disease, 25 of 33 patients who completed the trial were helped significantly by the drug, as shown by both clinical and laboratory findings. Placebo helped in 4 of 33 patients. The difference is significant (p less than 0-001). These are the results for the trial period only. The results of follow-up for 6 to 30 months are available in 18 patients: 14 of these still had appreciable help from the drug, which was continued in maintenance doses. It should be noted that 3 of 6 diabetics were no longer helped after 6 months, and that only 3 of a total of 7 patients under the age of 50 were helped; however 3 of the 4 not helped were diabetics under the age of 50. Special caution was indicated in the use of the drug in patients who have ischaemic heart disease in addition to their peripheral arterial disease. Side-effects were common, particularly a severe prolonged flush shortly after taking a dose of the drug; many patients helped by it accepted this side-effect if it occurred. Xanthinol nicotinate reduced whole-blood viscosity and cholesterol and fibrinogen in about half of the patients helped. This is a useful drug for about half the patients in whom surgery is not indicated or is contraindicated.

Adult↗
PubMed1977

[A case of Ehlers-Danlos syndrome].

A case of Ehlers-Danlos syndrome, personally observed, is described. Stress is laid on the rarity of this syndrome (less than 200 cases in the world literature) and on its peculiar symptoms. The familial character of this syndrome was not proved in the case observed.

Capillary Fragility↗
PubMed1989

Manufacture and use of fused silica cannulas for intracerebral injections in freely moving rats.

This report describes in detail the assembly and use of miniature cannulas for intracerebral injections in freely moving rats. Guide and injection cannulas were prepared from polyimid-coated fused silica capillaries as routinely in use for gas chromatography, in this way avoiding the permanent contact of stainless-steel with brain tissue. The outer diameter of the guide capillary measured 300 microns, that of the injection capillary 170 microns. In spite of their fragile appearance, the capillaries were robust and easy to handle. In the same animal, up to 20 consecutive injections were possible. In the course of 2 years 204 cannulas directed to the amygdala or the lateral ventricle were implanted, and only in 8 rats (4%) the inner capillary broke and plugged the guide cannula, making injections impossible. Histological examination of brains implanted for up to 2 months demonstrated only blunt scar formation along the cannula's track. No changes in transmitter levels (biogenic amines, amino acids) could be detected in chronically implanted rat brains except for a slight increase in serotonergic activity in the contralateral piriform cortex. Intra-amygdaloid injection of 0.32 microliters 0.9% saline resulted in a mild and transient reduction of GABA levels in both piriform cortices, without any detectable persistent histopathological consequences.

Animals↗
PubMed1982

Coil planet centrifugal and capillary tube centrifugal analysis of factors regulating erythrocyte osmotic fragility and deformability.

Hydrated and dehydrated red cell samples were prepared from normal human red cells using the antibiotic nystatin. Furthermore, a series of red cell samples exposed to elevated temperature (20-50 degrees C, 10 min) were prepared. The osmotic fragility and deformability of these red cells were then measured, using the coil planet centrifuge system and the capillary tube centrifugal technique, respectively. The osmotic fragility of nystatin-treated red cells decreased and the deformability increased as dehydration of red cells progressed and alternatively, hydrated cells showed increased osmotic fragility and reduced deformability. Red cells exposed to elevated temperatures up to 49 degrees C for 10 min had no changes in mean corpuscular volume or in red cell shape. Above 47 degrees C, however, spectrin extractability progressively decreased and osmotic fragility and deformability decreased. Results suggest that the osmotic fragility snd deformability of red cells are interrelated, and are controlled by the geometry of the cell, including the ratio of cell surface area to cell volume and the viscoelastic properties of the membrane.

Centrifugation↗
PubMedDate not supplied

Reduced thermal sensitivity of the vasculature in a slowly growing tumour.

The thermal sensitivity of a slowly growing murine mammary carcinoma has been studied, and correlated with several vascular parameters. This tumour, CaRH, had previously been shown to be particularly resistant to hyperthermia when applied as 1 h immersion in a 42.8 degrees C water bath, with or without added X-rays. In the present study water bath temperatures of 43, 44 and 45 degrees C were used as well as a more complex system of water bath plus radiofrequency currents which produced a uniform intratumour temperature of 43 degrees C. Following treatment the tumour blood volume and relative capillary perfusion were estimated using radioactive tracer techniques. Only the treatments which gave at least 60 per cent reduction in blood perfusion yielded significant growth delays or thermal radiosensitization. These data have been compared with values for six other murine tumours. If, instead of comparing the exposure temperature, we compare the blood flow reduction, it is seen that all of the tumours are similar in their thermosensitivity. A higher temperature may be needed to cause vascular shutdown in more slowly growing tumours, but it is achieved with an intratumour temperature of 43 degrees C for 1 h. This may correlate with endothelial cell proliferation rates, which are similar in CaRH to the values measured in human tumours. The more rapid vascular expansion of the fast-growing tumours may result in a more fragile and thermosensitive capillary network. The hypoxic fraction, which is a measure of vascular inadequacy, also correlates with thermal sensitivity.

Animals↗
PubMed2002

Electron microscopic study of monkey retina after photodynamic treatment.

The purpose of this histological study was to determine the effects of photodynamic treatment, using a hematoporphyrin derivative and argon laser, on normal retinas of monkeys. Ten cynomolgus monkeys were treated with a hematoporphyrin derivative, given intravenously at a dose of 2.5 mg/kg. Forty minutes or 1 or 3 days after the injection, argon laser photoradiation was given over a 2.0-mm-diameter with a 10-min exposure and at an intensity of 40, 100, or 200 mW. The eyes were enucleated 1, 3, 4, 15, 18, 21, 35, or 38 days after the photoradiation and tissue samples were observed under a transmission electron microscope. The most fragile regions in the retina were the retinal nerve fibers, the outer segments of the visual cells, and the retinal pigment epithelium. Vascular endothelial cells were also fragile. The retinal capillary was easily obstructed, and the choriocapillaris was also occluded in an animal with severe retinal damage. The Mueller cells had the highest tolerance to the photodynamic treatment. Thus, exposing the normal part of the retina to light during photodynamic therapy should be avoided.

Animals↗