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[The behavior of blood clotting and its inhibitors under long term treatment with 5,6-benzo-alpha-pyrone (coumarin). Double blind study].

The analyses on hemostaseological variables are recorded in connection with blood tests in the course of a double-blind study in 41 patients suffering from chronic venous insufficiency of higher degrees of severity. They were treated in addition to compression measures with two active ingredients, a coumarin (5,6-benzo-alpha-pyrone)/troxerutin combination (Venalot Depot) (n = 20) or benzarone (n = 21) receiving 3 X 2 dragees daily for 6 weeks. Good clinical efficacy and the improvement of symptoms were observed together with almost no side-effects. The coagulation analysis showed no influence of the active principles on the global coagulation or the clotting factors and the inhibitors and factors of the fibrinolysis. In particular there was no phenprocoumon-like effect on the blood clotting system.

Anticoagulants↗

Fine structural aspects of the influence of lymphatic blockage on cold injury of the brain and skin, and the effects of benzo-pyrones.

The fine structural changes of cold injury, lymphoedema, or both have been studied in the cerebral cortices and facial skin of rats, with and without treatment by a mixture of two benzo-pyrones (coumarin and rutin sulphate salts). It was found that cold injury opens the endothelial junctions of the blood vessels and injures their plasma membranes, thus allowing plasma protein and fluid to enter the tissues, producing oedema. Hence the lymphatics of the skin and the prelymphatics of the brain become dilated, contain excess protein, and the junctions of the former become opened. Macrophages (together with astrocytes in the brain) appear to phagocytise some of the protein. Apart from the injuries to the blood vessels, lymphostasis causes similar effects. The two injuries in combination considerably enhance the effects of either by itself. The benzopyrones greatly reduce the amounts of protein and fluid, particularly in the tissues: the lymphatics lag behind these, especially if they are obstructed.

Animals↗

Semi-complete versus partial venous obstruction, with and without partial lymphatic obstruction, and benzo-pyrone treatment.

The alterations in the fine structure of the venous wall are reviewed, and the changes which occur with injury. These are very similar in both arteries and veins, and were also found by us in experiments in which the common iliac veins of rats were completely occluded, with or without partial lymphatic obstruction. It was found that the protein concentration was considerably increased in the vein wall, in the muscle, and in the skin of the leg--especially when the lymphatics were blocked as well as the veins. The effects of various procedures, including partial and semi-complete venous obstruction and lymphatic obstruction were examined. It was shown to be likely that in semi-complete venous obstruction the blood in the occluded vessels is ultrafiltered, causing great increases in protein concentration, which will be transmitted to the tissues in general--although not to the tissue channels and lymphatics. This will not happen in partial venous occlusion. In all of these cases the benzo-pyrones considerably reduced the amount of excess protein in the tissues. This was no doubt partly due to their abilities to cause increased proteolysis, but may also have been due to their effects on blood and lymph vascular tone and functioning.

Animals↗

The effect of benzo-pyrones on the canine pancreas submitted to long-term hypothermic perfusion.

In 14 dogs pancreatectomy was performed and pancreas was submitted to 24 hour hypothermic pulsatile perfusion using Gambro machine. During the perfusion exocrine secretion subsequent to secretin and CCK stimulation was collected and the perfusion fluid was analyzed. In 7 of these animals, Venalot, a combination of coumarin and rutin sulphate, was added to the perfusion fluid and its effect was tested. The addition of Venalot was followed by a decreased vascular peripheral resistance, decreased weight of the perfused graft, and decreased level of LDH and lactic acid in the perfusion fluid. The release of potassium from the pancreatic cells was prevented. The parameters of the pancreatic secretion was better than in the control group. Benzo-pyrones reduced oedema formation and improved cell metabolism during hypothermic perfusion of the pancreas.

Amylases↗

Postinflammatory oedema in two patients with contact dermatitis. Effect of benzo-pyrones.

Two female patients with oedema of the arms and legs due to contact dermatitis complicated with recurrent infections were examined. The concentrations of plasma proteins of different molecular weight in the oedema fluid (collected from suction blisters) were highly increased. Albumin outflux as measured with radiolabelled albumin from the vessels of oedematous skin was markedly decreased corresponding to a decreased lymphatic function. Treatment with benzo-pyrones for 6 months did reduce the protein concentrations of the oedema fluid, but the clinical response was disappointing.

Albumins↗

The use of 5,6 benzo-[alpha]-pyrone (coumarin) and heating by microwaves in the treatment of chronic lymphedema of the legs.

Sixty patients with leg lymphedema from a variety of etiologies were divided into randomized two groups, matched by Grade, duration, age, sex, and cause of lymphedema. Using a double-blind format, one group received 5,6 benzo-[alpha]-pyrone (coumarin 1,2 benzopyrone, 400 mg/day) for six months; the other received a placebo. For the next six months, both groups received a standardized regimen of heat (using microwaves) coupled with compression garments. Benzopyrone produced approximately 20% reduction in the volume (p = 10(-4)) and improvement in circumferences and tonometry (p = 10(-5) and 10(-7)). Symptoms (feelings of swelling, pain, heaviness and loss of mobility) were also significantly improved (p = 0.03 to 10(-7)). During the second six months, when microwave heat therapy was added to drug therapy, the patients who had previously received the placebo showed significant improvement (p = 0.03 to 10(-9)) in signs and symptoms of lymphedema. Some, but not all, of the group that was receiving benzopyrones were also significantly improved by heat therapy (p = 0.8 to 0.002). Taking benzopyrones for 12 months plus heat treatment for six months was significantly better, for some criteria, than the placebo plus heat therapy (p = 0.7 to 0.04). On the other hand, heat plus either placebo or benzopyrone was often significantly better than either the active or inactive drug without heat (p = 0.8 to 10(-9)).

Administration, Oral↗

Species-dependent enantioselective pharmacokinetics of PNU-103017, a pyrone HIV protease inhibitor.

PNU-103017, 4-Cyano-N-(3-(cyclopropyl(5,6,7,8,9,10-hexahydro-4-hydroxy- 2-oxo-2H-cycloocta(b) pyran-3-yl)methyl)phenyl)-benzenesulfonamide, is a selective HIV aspartyl protease inhibitor under evaluation as a potential oral treatment of Acquired Immunodeficiency Diseases. PNU-103017 is a racemic mixture of two enantiomers, designated PNU-103264 (R-) and PNU-103265 (S-). Stereoselective pharmacokinetics of the two enantiomers of PNU-103017 were observed in the dog, rat, and human after single and multiple dose administration of the racemate and were apparently species-dependent. Mean enantiomeric ratios of plasma concentrations (R-/S-) at each time point were greater than 1 in the dog, ranging from 1.22 to 3.06, but less than 1 in the rat and in the human, ranging from 0.44 to 0.80 and 0.23 to 0.73, respectively. A trend towards increased or decreased (farther from 1:1, R-/S-) enantiomeric ratio of plasma concentrations with time after each administration was also observed. The enantiomeric ratio remained unchanged after multiple dose administration in the rat, dog, and human although enzyme induction and increased plasma clearance were observed for both enantiomers.

Animals↗