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PubMedDate not supplied

Prevention of ionizing radiation-induced liver microcirculation changes by the use of flow improvers.

Platelet aggregation and adhesiveness, as well as TpO2 responses to hypoxia were measured as microcirculation parameters in beagle dogs subject to Co60 ionizing radiation to a dose of 4600 rads in 5 weeks. Simultaneously, changes in blood chemistry and coagulation were also determined. Marked changes in all studied parameters in the post radiation period lead to the conclusion that the radiation liver damage, which is at least in part mediated through microcirculation disturbances, can be prevented with the flow improver, Rheomacrodex.

Animals↗

PubMed1976

Thrombus formation, hemostasis, adhesiveness of leukocytes and morphological abnormalities in the microcirculation of adjuvant arthritic rats.

Microcirculatory alterations which may be responsible for the chronicity of adjuvant-induced arthritis in the rat were investigated. Thrombus formation in the mesenteric microcirculation was investigated by laser-technique. In arthritic rats thrombus formation for a given stimulus was increased significantly and a correlation was found between the intensity of the arthritic changes and this thrombotic reaction. Adherence of leukocytes to the venous endothelium was studied by an in vivo technique. The number of "rolling" and "sticking" leukocytes was greatly increased in the mesenteric venules of arthritic rats. Acute treatment of severely arthritic rats with aspirin greatly reduced the increased adhesiveness of granulocytes. By the use of an atraumatic technique for vital microscopy of the microcirculation of skin of arthritic rats, striking morphologic changes with stasis of erythrocytes were observed. Morphological aberrations were also found in the mesenteric microvessels of diseased animals.

Adhesiveness↗

PubMed1979

Are epinephrine and gastrin accelerative factors of acute cinchophen ulcer?: Studies on gastric mucosal microcirculation and gastric secretion.

Measurements of serum epinephrine and gastrin, simultaneously, gastric mucosal blood flow and gastric secretion were carried out in cinchophen treated dogs. No significant changes in either serum concentrations of epinephrine and gastrin or fundic mucosal microcirculation after a single 100 mg/kg cinchophen administration were found while gastric secretion increased markedly after the medication. On the other hand, a significant increase in serum epinephrine and gastrin levels was observed while gastric secretion decreased significantly after large doses of cinchophen (300 mg/kg) were injected intravenously. Here gastric mucosal microcirculation is decreased. Repeated administration of 100 mg/kg cinchophen for 3 to 7 days brought about an increase in epinephrine and gastrin levels and caused an occurrence of fundic mucosal hemorrhage. Sympathetic discharge and gastrin release were not seen after a 3-week period of cinchophen administration. Cinchophen ulcers were produced, even when contact between the bile and the stomach mucosa was avoided. Vagotomy had no connection with ulceration and gastric secretion.

Animals↗

PubMed1975

Histamine receptors in the synovial microcirculation.

This study was designed to investigate the respective roles of H(1) and H(2) receptors in the control of the microcirculation by examining the effectiveness of the H(2) receptor antagonist metiamide (Met.) and H(1) receptor antagonist mepyramine is blocking the action of histamine on synovial perfusion. Synovial perfusion was monitored indirectly by calculating the half-life (T1/2 min.) of the clearance rate of 133-Xe from canine diarthrodial joints. The 133-Xe clearance rate, unaffected by metiamide alone, was consistently increased by histamine alone. Metiamide produced a dose related effect on the histamine response with consistent abolition of response at high dose ratios of metiamide to histamine variable response at intermediate and a pronounced histamine response at low dose ratios. Mepyramine produced no such antagonism of the histamine response and in certain doses, by itself caused an increase in 133-Xe clearance rate. This effect of mepyramine was thought to be related to its histamine releasing properties a view supported by the reduction in this vasodilator response following certain doses of metiamide. The response of the 133-Xe clearance rate to histamine returned approximately one hour after treatment with metiamide (500 mug) and metiamide did not antagonise the effects of alpha and beta adrenergic agents on the 133-Xe clearance rate. Thus, this study has provided evidence for the presence of H(2) but not H(1) receptors in the synovial microcirculation.

Animals↗

PubMedDate not supplied

A contribution to the physiology of the perilymph. Part IV: Effect of histamine on the cochlear microcirculation.

Summary--Because of the topography of the perilymphatic vascular network, the cochlear microcirculation is especially sensitive to the effect of vasoactive substances reaching the perilymphatic space. The cochlear microcirculation is mainly controlled humorally, via the activity of the metarterioles and changes in the flow properties of the blood. Intracochlear histamine reduces the cochlear circulation even more markedly than after intracarotid administration. No systematic effects of parenteral administration of vasoactive substances can be expected on the cochlear circulation. Reversible auditory disorders after stapedectomy may be explicable by the intracochlear release of histamine. The internal release of histamine after sunstroke and cold stress may play a part in sudden dusturbances of hearing.

Animals↗

PubMedDate not supplied

In vivo observation of tracheal microcirculation in dogs.

Tracheal microcirculation was studied in six healthy anesthetized adult mongrel dogs. A transparent balloon was used to apply pressure to the tracheal mucosa during observation of the microcirculation. Pressures of microvascular occlusion were measured using an electrically callibrated silicone, envelope placed on the observation balloon. The different vessel sizes were measured and classified using the operating microscope. Capillary occlusion pressures ranged from 10 to 40 msurements of tracheal diameter were performed. Progressive local and generalized dilatation occurred. Capillary occlusion pressure was lower in the more dilated specimens. The lower than expected occlusion pressures are thought to be a result of the tracheal dilatation and may be related to the administration of drugs or other factors.

Animals↗

PubMed1979

Relations between disturbances in microcirculation and accumulation of lipids in the aortic wall.

For the purpose of unraveling the relations between disturbances in microcirculation and deposition of lipids in the aortic wall, 9 rabbits were fed a 1% cholesterol and 5% coconut oil at intervals up to 16 weeks, and 4 rabbits were used as controls. After microangiography of vasa vasorum, the same specimens were studied histochemically. The distribution of vasa vasorum became poorer on sacrifice by microangiography. However, it could not be thought that disturbances in vasa vasorum was a cause in the early deposition of lipids, because lesions were histologically mild in the greater parts of vasa vasorum. The sites of prediction for the vascular lesions were initially the branching part, and then the thoracic aorta. Thickness and numbers of the elastic lamina in the media decreased straightly in the distal direction, and the degree of intimal thickening and accumulation of lipids were parallel with the degree of the medial thickness. The intimal cells tended to be arranged radially with wide intercellular spaces in the cross section, suggesting the convenience for the passage of fluids. From the above facts, it may be reasonable to presume that the difference in severity of disturbances of microcirculation resulted in the difference in the site of predilection.

Angiography↗

PubMed1979

Effects of vasodilators on microcirculation of the rat cremaster muscle: a microscopic method for screening drugs.

Effects of vasodilating drugs on microcirculation of the rat cremaster muscle were investigated microscopically. Topical application and intravenous injection of papaverine produced dilatation of arterioles. Cyclandelate applied topically dilated the arterioles to a considerable extent. Topical application of bamethan induced arteriolar dilatation while bamethan given intravenously constricted the arterioles. Kallikrein applied topically induced a slight dilatation of arterioles, and intravenous administration of kallikrein produced an appreciable vasodilatation. Topical administration of bradykinin produced a vasodilatation of arterioles of the rat cremaster muscle. These results indicate that direct action of a drug on the microcirculation can be properly evaluated by the microscopic method in the rat cremater muscle, if the drug is applied topically, in the vicinity of small vessels under study.

Acetylcholine↗

PubMedDate not supplied

[The physiology of microcirculation].

Since the work of Harvey and Malpighi, there have been more questions than answers in the physiology of the microcirculation. The microvessels and the interstitial connective tissue form a true functional and structural unit in which the capillary is only a passive feature. It is subject to the constraint of the connective tissue that surrounds it, is only a reflection of the hydraulic conditions above and below it and is a luxury metabolic pathway compared with the importance of the derivative or shortcircuit arteriovenous pathway in which the metarteriole is of major importance. Continual renewal, apparent vasomotor character, and extreme permeability sum up the physiology of the microcirculation. The cybernetics is dominated by the arteriolo-venular functioning and by chain rections. Stasis, the opening of arterio-venous anastomoses, and sludge are the main pathological features. Investigation of capillary function remains difficult under clinical conditions, since different methods give a global picture, that of the vascular-tissue unit.

Capillaries↗

PubMed1976

[Role of microcirculation in the development of pulmonary hypertension in chronic non-specific lung diseases].

A comparison of the results of morphological studies of pulmonary and pleural microcirculation with the indices of haemodynamics in the system of the pulmonary artery in patients with chronic non-specific lesions of the lungs accompanied by suppurative processes indicates the participation of microcirculation in the development of pulmonary hypertension. A lasting course of the disease with frequent exacerbations results in profound changes in the system of micricirculation. The pathological developments in the vascular terminals, the disorders in the rheological properties of the blood, in vascular permeability- the hampered lymph drainage that are the causes of irreversible metabolic shifts not only become additional factors in the development of the underlying pathology, in the formation of bronchiectases in particular, but also provide for a further development of pulmonary hypertension.

Adult↗

PubMedDate not supplied

[Medullary microcirculation in human primary and secondary myeloscloroses].

There are histological and experimental evidence for bone marrow microcirculation to play a role in histogenesis of myelosclerosis. Human sternal bone marrow microcirculation was studied after death using ink injection in two cases of primary myelofibrosis, two cases of secondary meylofibrosis (Hodgkin's disease) an one case of osteomyelosclerosis. Control material consisted of 30 previously studied normal human sternums. In all cases interadipocytic sinusoidal network has completely disappeared. Medullary vascularization is anarchic with a vascular and hypervascular areas. The significance of these modifications is discussed.

Aged↗

PubMed1975

[The effect of the argon laser on the vessels, the macro- and microcirculation of the mucosa of the hamster cheek-pouch. An intravitalmicroscopic study (author's transl)].

The mucosa of the cheek-pouch of five golden Syrian Hamsters was irradiated with the beam of an argonionlaser (diameter 0.5 mm and 200 mW). The effect on the micro- and macro-vessels and the bloodstream, especially of the microcirculation, is studied intravitalmicroscopically. In the microcirculation and also in the small and large venous and arterial vessels a restriction of bloodstream, praestasis, pendulumstream, stream reversal and some white microthrombi, -- emboli and agglutination of erythrocytes are visible. The bloodless welding of the vessels takes place even before the evaporation and coagulation necrosis of the surrounding epithelium of the mucosa as a result of the relatively selective effect of the Argon Laser on the reddish vessel-system by a continuous narrowing of the vessels-walls to the complete loss of their lumen rather than by a thrombosis. Firstly the capillaries, the venoles and the arterioles are obliterated, then those of middle size and at last the large venae and arteries in which case large vessels function for a moment as smaller ones. A continuously growing imbibition with increasing duration of the laser irradiation can be observed. Three clinically important phenomenon, depending on the laserdose can be observed: 1. a partial, 2. a subtotal and total obliteration of the network of the vessels, and 3. a total destruction of the blood-vessels and also of the tissue. Therefore clinically a subtotal or total network obliteration of the blood-vessels of strongly vascularised tissues, haemangiomas, teleangiectasias in case of morbus Rendu-Weber-Osler and livid enlarged nasal conchae might be obtained. Further a total tissue-destruction with a break in the continuity of the tissue for example with strongly vascularised carcinoma or its metastases might be effected.

Animals↗

PubMed1975

The problem of tissue oxygenation in diabetes mellitus. I. Its relation to the early functional changes in the microcirculation of diabetic subjects.

The underlying cause leading to the reversible functional changes in the microcirculation of insulin-dependent diabetic subjects early during the disease prior to any clinical signs of retinopathy and nephropathy (functional microangiopathy) is discussed. It is suggested that the initial microvascular dilation observed in diabetics is due to an autoregulatory response to relative tissue hypoxia providing an increased tissue perfusion in order to improve tissue oxygen delivery. Supporting evidence for this suggestion is derived from the findings that diabetics simultaneously may show increased tissue oxygen consumption and decreased ability of the circulating blood to release oxygen to the tissues. The latter defect is likely to be caused by two interrelated factors: 1. an increased proportion of haemoglobin A1c with high oxygen affinity, and 2. difficulties of maintaining a sufficiently high concentration of plasma inorganic phosphate in order to provide an optimal 2,3-diphosphoglycerate (2,3-DPG) content in the erythrocytes. The basal oxygen demand of diabetics may fluctuate even within a few hours dependent upon the state of metabolic control and is increased at times of poor regulation. Hence, diabetics may suffer from innumerable cellular hypoxic injuries, which during the first years of the disease are counteracted in the microcirculation by an autoregulatory response. These microvascular reactions associated with increased plasma permeation may over the years be of major importance for the development of the degenerative microangiopathy in diabetes.

Diabetes Mellitus↗

PubMed1978

[State of the microcirculation in periarteritis nodosa based on morphological and biomicroscopic data].

The status of microcirculation in periarteritis nodosa was studied by impregnation method (serous membranes) and biomicroscopy (eyeball conjunctiva). Pathological and adaptative changes in terminal vessels were found. It is suggested that the involvement of microcirculation ways in this disease is systemic and that morphological changes in microvessels are comparable to biomicroscopic changes.

Adolescent↗

PubMed1979

[Effect of short-term cerebral ischemia on the microcirculation in the rat mesentery].

The effect of brain ischemia, produced by constriction of the common carotid arteries, on microcirculation in the mesentery was studied in experiments on rats. The spreading and intensity of microcirculatory disturbances were dependent on duration of ischemia and post-ischemia. The state of systemic hemodynamics and microcirculation in the mesentery was compared. Possible mechanisms of the microcirculatory disturbances are discussed.

Animals↗

PubMedDate not supplied

[Disorders of microcirculation in diffuse toxic goiter and their correction in the early postoperative period].

A study was made of microcirculation in 45 patients suffering from diffuse toxic goiter at the early postoperative period with the aid of microphotography of the bulbar conjunctiva vessels, and investigation of the rate of the isotope elimination from the intradermal depot and the capillary permeability by V. P. Kaznacheev's method. The data obtained permitted to draw a conclusion that on admission to the clinic patients with toxic goiter were suffering from arteriolar spasm, had poor vascular pattern in the bulbar conjunctiva, the sledge phenomenon in small venules, an acceleration of the isotope elimination from the intradermal depot and an increase of the capillary permeability. Preoperative preparation improved the microcirculation indices, without completely normalizing them, however. Microcirculatory disturbances reached their maximum the first two days after the operation and declined by the 3rd-5th day. Recommendations on correction of the microcirculatory disturbances are given.

Adolescent↗

PubMedDate not supplied

[State of the microcirculation in diabetes mellitus (based on conjunctival biomicroscopy data].

Conjunctival biomicroscopy was applied to the study of microcirculation in 30 healthy persons and in 112 patients suffering from diabetes mellitus before and after the treatment. Marked darangement of the end blood flow was expressed in the appearance of perivascular, vascular, and intravascular lesions, increasing with the progress of diabetes mellitus. Adequate therapy gave positive results with the disappearance or reduction of perivascular lesions in the microcirculation, and also improvement of the rheological properties of the blood.

Adolescent↗

PubMed1976

[Tissue microcirculation in patients with reflex neurodystrophic syndromes of cervical osteochondrosis].

In 62 normals and 70 patients with reflex vertebrogenic syndromes the authors studied tissue clearance (the time of resorbtion--50% and 80% isotope, the mean rate of elimination in percentage) by radioisotope indications. The study determined as well the informative value of radiogramm indices. The data reveal distinct disorders of tissue microcirculation in the affected areas. It was also possible to establish a correlation between the capillarotissue metabolism and the duration of the disease, duration of the exacerbation, stage of the disease and some other factors. The authors followed the development of microcirculation in the process of treatment. The obtained results indicate the diagnostical significance of the method of radioisotope indication and the possibility of its application for the prognosis of the disease and evaluation of treatment methods of reflex neurodystrophical syndromes of cervical osteochondrosis.

Adult↗