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Hypoxic-ischemic insult is a most common form of perinatal brain damage that threatens a newborn's life and can leads to permanent neurological sequelae. However, detailed aspects of the cerebral ischemia in the immature brain stay unanswered. We decide to use the model of focal cerebral ischemia induced by intrahippocampal endothelin-1 (ET-1) in 12-days-old rats. The knowledge about consequences of ET-1 induced ischemia and the role of endothelin receptors (ETA and ETB) in ischemia-induced consequences in immature brain are poor at present. Agonists and selective antagonists of the ETA and ETB receptors were used to determine the role of these receptors in the development of ischemia, changes in regional blood flow and tissue oxygenation, local changes of biochemical parameters and acute neuronal death. Our results indicates, that activation of the ETA receptors causes a strong decrease of the blood flow, induced related hypoxia and subsequent neuronal degeneration, whereas activation of ETB receptors has likely modulatory role. Moreover, ischemia causes increase of excitatory amino acids concentration, whereas inhibitory amino acid, except taurine, decreased after ischemia. These facts provides new insights in a case of perinatal ischemia. This thesis demonstrates the wide range of different effects of...

Microdialysis is a dynamically evolving method utilized for monitoring of tissue metabolism and barrier function, pharmacological studies and to estimate local blood perfusion in situ. The present review summarizes current knowledge of the last of the aforementioned applications on a characterization and comparison of two approaches used - microdialysis flow-indicator dilution technique and continuous metabolic monitoring. Currently, the use of metabolic indicators, which enable sensitive and complex evaluation of perfusion-induced changes in the tissue, is preferred. Despite the methods numerous advantages the measurement of tissue blood perfusion by microdialysis remains centralized in the area of clinical research, for the present. For wider acceptance and exercise in the routine clinical practice, more validating studies ought to be conducted and situations identified, where microdialysis could replace the current methods.

The aim of the prospective study was to find out the following: 1. What is the prevalence of deep vein reflux of the leg in patients with superficial vein reflux detected by ultrasonography? 2. What are the possible causes of deep vein insufficiency of the leg retrospectively detectable on the basis of targeted medical history? 3. Is the incidence of identified deep vein insufficiency of the leg gender specific? The sample consisted of 100 legs with superficial vein reflux detected on ultrasonography (C1 - C4 / CEAP) of 79 randomized patients (59 women aged 45 +/- 12 years and 20 men aged 52 +/- 15 years). We collected the medical history of all patients and examined them for any vascular diseases of the leg. Superficial and deep venous system of the leg was examined by routine duplex ultrasonography with 7.5 a 10 MHz linear probe in B-mode, colour flow mapping and pulse Doppler using Valsalva manoeuvre and manual compression of thigh. During the examination, patients lay both prone and on their back.Prevalence of deep vein reflux in patients with superficial vein reflux detected by ultrasonography was 43 %. Prevalence of deep vein reflux in patients only with primary venous insufficiency (i.e. personal medical history without phlebothrombosis of the leg, trauma, surgery or plaster fixation) was 35.4% in our sample. The possible causes of deep vein reflux in our patients are the following: overweight and obesity (58.6%), primary valvular insufficiency (35.4%), secondary valvular insufficiency--post-thrombotic, post-traumatic (34.9%) and various combinations of these factors. Deep vein insufficiency increased with the BMI. Deep vein reflux was significantly more frequent in men (80%) as compared with women (54.2%).

Hypoperfusion of peripheral tissues and splanchnic organs during cardiac surgery in extracorporeal circulation may lead to the origin of serious complications. The aim of the study was to monitor metabolism and blood pressure in interstital peripheral tissue, skeletal muscle, during the operation on the patient with extracorporeal circulation (ECC) in an early post-operation period by means of microdialysis.The interstitial microdialysis is a minimally invasive method for the biochemical monitoring of metabolic changes and blood pressure in extracellular space of tissue. The substances in interstitium pass across a semipermeable membrane of the inserted microdialysis probe and may be analyzed. Microdialysis in this study was performed by means of two microdialysis probes CMA (CMA Microdialysis AB, Sweden) inserted into the deltoid muscle of the surgically treated patient. The probes were perfused by the Ringer solution at the rate of 0.3 ml/hour. The dialysates were sampled in the following intervals: beginning of the operation, beginning of ECC, end of ECC, end of the operation, two hours during the post-operation period. Standard biochemical methods were to evaluate, in the dialysates, glucose, urea, glycerol and lactate. The blood flow in the interstitium was monitored by means of dynamic microdialysis of gentamycine as a marker. Microdialysis was performed in 40 patients with ischemic heart disease, operated on in the extracorporeal circulation. In 20 patients the ECC was performed in normothermia (NT), while in the other 20 patients it was made in hypothermia (HT).In both groups, NT versus HT, a similar dynamism of interstitial concentration of the observed substances in relation to the operation phase and in early post-operation period. Low initial concentrations were gradually increasing during the extracorporeal circulation and increased further after the end of extracorporeal circulation and also in the subsequent phase of the operation. The concentration values of the analytes under observation were higher in the groups operated on under normothermia, apparently due to normal cellular activity during normothermia (versus values in hypothermia). Immediately after the operation the observed values decreased in the both groups and subsequently gradually increased in the post-operation period in the both groups. The trend of dynamic changes of the observed analytes, selected as compounds indicating metabolic activity of skeletal muscles during hypothermia documents a lower metabolic activity of the cells during hypothermia and its marked increase (against NT) in the phase of subsequent normalization of the tissue temperature. Analysis of the concentrations of lactate, as a compounds mapping anaerobic metabolism of skeletal muscle, revealed similar dynamic changes in the both groups (NT vs. HT). There were no significant differences, related to the phase of the operation or the phase of immediate post-operation course when the both groups were compared. The analysis of gentamycine concentrations as a flow marker revealed lower gentamycine concentrations in dialysate during the operation, ECC and the early post-operation course in the group operated on in normotheramia (vs. HT), indicating a higher tissue flow in skeletal muscle against the group of patients operated on under hypothermia.The results of the microdialysis study demonstrated dynamic changes in interstitial concentrations of the observed compounds (glucose, urea, glycerol and lactate) related to the phase of operation on the heart in extracorporeal circulation and in early post-operation period. A higher perfusion of skeletal muscle was documented in patients operated on under normothermia. It became obvious that the dynamism in the changes of the compounds observed in the interstitium of skeletal muscle was determined by metabolic activity of the tissue as well as by blood flow in the muscle interstitium.

Parathyroid hormone (PTH)--besides its main osteotrophic action--exerts also vascular effect demonstrated formerly also in bones. The aim of the presented work was to verify this effect of PTH using the radioactive microsphere method and to ascertain simultaneously whether NO does participate or not in this effect of PTH. We performed two experiments which were arranged in the same way, as follows: group I--controls, group II--PTH, group III--L-NAME, group IV--L-NAME + PTH. Parathyroid hormone 1.34 fragment (Sigma, USA) was administered to each animal 6-12 minutes before the injection of radioactive microspheres in the dose of 3 micrograms in the experiment A, 10 micrograms in the experiment B. NG-nitro-L-arginin methyl ester (Sigma, USA) was given in the food for ten days before the experiment in the concentration of 0.025% in experiment A, 0.05% in experiment B.We present the results of experiment A in the part "Results" of the paper briefly in percentages--they are similar to the results of experiment B, but without statistical significance. Administration of PTH increased statistically significantly the microsphere uptake in tibia and distal femur and also the blood flow in both bones, increased the cardiac output and lowered blood pressure. Administration of L-NAME alone induced decrease of the heart rate only. After the injection of PTH to the rats fed L-NAME there was--compared to the injection of PTH only--the blood flow through both bones significantly lower. The observed increase in the bone blood flow as well as changes in the general circulation show that i.v. injection of PTH under the experimental conditions used does induce vasodilatation in female rats. Influence of these changes by the administration of L-NAME indicates possible participation of the nitric oxide (NO) in the observed effect of PTH on the vessles.

We present the results of two experiments aimed at the role of IGF-I and NO in the regulation of bone blood flow. In the first experiment A we determined the blood circulation in tibia and distal part of femur and the blood level of IGF-I after oophorectomy (OOX, 4 weeks before the experiment) and/or administration of NG-nitro-L-arginin methyl ester (L-NAME, Sigma, USA, 0.05% in the food for 10 days before the experiment). In the second experiment B we checked up the possibility of correlation between the bone blood flow and IGF-I level in female rats control and after the administration of estradiol (Agofollin Depot, Biotika, Slovak Republic, 1 mg s.c., two times weekly, for 4 weeks before the experiment). The bone blood flow was ascertained by means of 85-Sr microsphere (NEN, USA) technique, IGF level was estimated with Rat IGF-I RIA kit (DSL, USA).Experiment A: group I: controls--sham operation, group II: oophorectomy (OOX), group III: L-NAME + sham operation, group IV: OOX + L-NAME. OOX elevated the 85-Sr microsphere uptake and bone blood flow in tibia and distal femur. The administration of L-NAME to non-castrated females lowered significantly the blood flow in the femur only, whereas in OOX females it inhibited completely the usual OOX-induced increase in circulatory indicators in both bones. IGF-I level was higher after OOX, administration of L-NAME did not exert any effect on it. Experiment B: group I: control females, group II: estradiol. After the administration of estradiol, there was marked decrease in the uptake of 85-Sr microspheres and blood flow in both bones, decrease in body weight, cardiac output, heart rate, blood pressure and also in the blood level of IGF-I. Density and ash weight of the tibia were elevated. Important results found in the group I of experiment B seem to be the correlations between the blood level of IGF-I and 85-Sr microsphere uptake in tibia (r = 0.68, p0.01), between IGF-I and blood flow in tibia (r = 0.54, p0.05) and between IGF-I and 85-Sr microsphere uptake in distal femur (r = 0.55, p0.05). However, in the group II of females after estradiol no significant dependence could be demonstrated. The results support the conception of the role of IGF-I and NO in the regulation of local blood flow also in the bones of rats. The possible sequence of the interrelations could be as follows: OOX--increase in the blood level of IGF-I--increase in the production of NO--vasodilatation and increase in the bone blood flow. Significant correlations between the blood level of IGF-I and bone blood flow represent further evidence of the participation of IGF-I in the regulation of bone blood flow in rats.

The authors paid attention to revealing as precisely as possible anatomical and haemodynamic conditions in venous vascular bed in the course of ultrasonographic examination of 309 lower extremities with clinical manifestations of chronic venous insufficiency (CVI). A combined reflux in the superficial and deep venous system (53.7%) or isolated reflux in superficial veins (25.9%) proved to be the most frequent pathogenic bases of CVI. Pathophysiology of varices was mostly based on the venous reflux and the primary idiopathic CVI was mostly present (98.1%). The post-thrombotic partial obstruction of the deep venous system (post-thrombotic venous changes on the walls) was demonstrated exceptionally (1.9%). A high coincidence of reflux in the deep and superficial venous system points out to s.c. secondary reflux in the deep veins originating on the basis of primary reflux in the large or small saphena. An attempt was made to clarify, whether the development and frequency of incompetent perforators is directly connected with the presence and seriousness of reflux in the large and small saphena. The presence and severity of large saphena insufficiency does not univocally indicate the presence of dilated or insufficient perforators on the medical side of the crus, where these anastomoses are present most frequently. The large saphena is a long vein typically suffering from segmental insufficiency, i.e. reflux affecting a certain portion, whereas other parts of the vein may be fully competent. Anatomical venous variability and abnormalities on lower extremities were demonstrated in every fifth extremity (62 extremities, 20.1%). Most of them concerned large saphena (39 extremities, 62.8%), small saphena being second (15 extremities, 25.2%). Other anatomical deviations occurred sporadically as solitary findings. In the large saphena, duplication was present most frequently (54.8%). Insufficient variable superficial veins and anatomical venous anomalies were mostly not the only pathogenic basis of CVI, but were predominantly associated with insufficiently in the area of deep veins and perforators (84%). In our cohort there were altogether 55 extremities (17.8%) after the operation on superficial venous system, where relapses of varices were found. The causes of post-operation relapse of varices may be divided into three groups: 1. insufficiency of the large saphena, 2. insufficiency of the small saphena and 3. insufficiency of the deep veins. A combined simultaneous insufficiency in several venous systems was found most frequently (27 extremities, 49.1%). Even though the reflux in the deep veins was demonstrated in 50.9% of these extremities, a combination with the reflux in superficial veins and perforators (49.1%) was present with the exception of one case of isolated insufficiency. The insufficiency of the large and small saphena was clearly the leading single causes (15 extremities, 27.3%) of varix relapses. The patients should never be operated on the venous system of lower extremities without previous detailed ultrasonographic examination. It is the only way to increase probability of the operation success and to decrease the risk of relapses of CVI manifestations.

Vascular access complications represent leading morbidity of hemodialyzed patients. Duplex Doppler ultrasonography is used rarely in the diagnosis of vascular access complications, despite its simplicity and widespread availability. Our first experience with this method is described, namely the most frequent indications, findings and the access blood flow correlation.356 examinations of both natural and polytetrafluoroethylene (PTFE) accesses at 193 patients were performed. The 7.5 MHz linear array ultrasound transducer of Hewlett-Packard SONOS 2000 device was used. Both arterial and venous parts of fistulas were examined in all cases. Screening examinations represented the most frequent indication, the hemodynamically significant stenosis the most frequent finding. Only 12.5% of PTFE-shunts and 25.8% of natural fistulas were described as normal. Mean blood flow through antebrachial and brachial accesses was 575 and 1070 ml/min, respectively.Prevalence of vascular access complications (especially that of stenoses) is high. Wider use of this method could bring significantly improved care for the dialysed patients.

In our previous work [7] we demonstrated that the bisphosphonate pamidronate lowered the bone blood flow of non-castrated female rats and inhibited the increase in bone blood flow after oophorectomy (OOX). In this paper we present the results of two similar experiments but also with the estimation of IGF-I in blood. The blood flow in the bones of female rats was estimated by means of 85-Sr microsphere technique (NEN, USA), the blood level of IGF-I was ascertained with Rat IGF-I RIA Kit (DSL, USA). Both experiments A and B were performed on female rats according to the same experimental scheme: group I--sham-operated controls, group II--OOX (four weeks before the experiment), group III--pamidronate (Aredia, CIBA-Giegy, 0.6 mg i.p. three days in the week, for four weeks), group IV--OOX + pamidronate. The results of both experiments can be summarized as follows:--it was confirmed again that OOX rises the circulatory indicators in the bones as well as the blood level of IGF-I;--pamidronate suppresses the increase in bone blood flow after OOX;--pamidronate does not unequivocally influence the level of IGF-I in blood. Thus, it is very probable that IGF-I plays a role in the increase of bone blood flow after OOX. However, it is still not clear how the deficiency of estrogens influences the blood level of IGF-I. The mode of action of pamidronate on the bone blood flow--mainly elevated after OOX--is not clear as well.

Pressure changes occurring during the activity of the calf muscle venous pump are the driving force of venous hemodynamics in the lower extremity. An ambulatory pressure gradient arises between the veins of the thigh and the lower leg as a consequence of pumping up the blood from the deep veins of the lower leg, where the venous pressure decreases, into the popliteal and femoral vein, where no pressure decrease occurs. Therefore, venous reflux can only take place in an incompetent vein connecting the femoral, profunda femoris, popliteal or iliac vein with one of the deep veins of the lower leg. Calf perforators represent the so called re-entry points and can't become the source of reflux. Venous reflex disturbs venous hemodynamics to a various degree dependent on the magnitude of reflux volume. When strong enough, it can produce the graviest form of chronic venous insufficiency even if localised in superficial veins. The magnitude of reflux volume, not the localisation of reflux in deep or superficial veins is the most important hemodynamic factor causing venous disturbance. The goal of varicose vein surgery is to remove reflux and visible varicose veins with the aim to achieve the most favorable hemodynamic and cosmetic results. Crossectomy is a very important step, because it is able to repair even the most pronounced hemodynamic disorder and restore normal hemodynamic conditions. If stripping of the incompetent saphenous trunk on the thigh is not performed in addition to crossectomy, the saphenous trunk continues to be patent and incompetent after surgery in most patients and provokes recurrent reflux. But nor can crossectomy combined with stripping avert the risk of recurrence definitively, because varicose veins are a dynamic disease with distinct tendency to recurrence. Correctly performed operation can reduce the recurrence rate and postpone its occurrence. A hemodynamic factor--the ambulatory pressure gradient--triggers probably the process leading to recurrence. When varicose veins recur, the recurrent reflux volume remains significantly lower for many years of follow-up as compared with the situation before surgery. External banding of incompetent valve in the long saphenous vein and the CHIVA-method are less efficient in comparison with standard surgery (crossectomy plus stripping). Sclerotherapy is a useful supplement to surgery during follow-up, as it is able to improve significantly the hemodynamic situation. This improvement is only transitory, but sclerotherapy can be repeated and the improvement re-established, if necessary, during follow-up.

The article describes novel method of vascular access quality assessment by means of combined measurement of recirculation with normal and inverse needles placement and calculation of vascular access blood flow from the recirculation data. Blood flow values seen in a large group of patients ranged from as low as 200 ml/min up to as high as 2 l/min. Females and diabetics exhibited lower values as compared to males and non-diabetics. The method enables to detect a number of anomalous sates which cannot be detected by conventional means based on monitoring of pressures or recirculation measurement at normal needles placement only (stenosis between both needles, uintentionally erroneous placement of needles in accesses with a loop). Assessment of access blood flow is suitable also for evaluation of interventions on the access, such as percutaneous transluminal angioplasty or surgical narrowing of anastomosis in case of too high blood flow.

The results presented contribute to the still unclarified question of the role of bone blood flow in the metabolism and mineralization of the bone tissue. We investigated correlation relationships between 85Sr-microsphere uptake (in % dose per g) or local blood flow (in ml/min per g) and density or ash weight (in g per ml of bone tissue) in the tibia of female rats. In four experiments a total of 16 correlations was computed. The following relationships were found statistically significant (p0.05): in exp. A (20 intact females): microsphere uptake--ash weight, blood flow--density, blood flow--ash weight, in exp. B (oophorectomy 4 weeks before the experiment, 28 rats): microsphere uptake--ash weight, blood flow--density, blood flow--ash weight, in exp. C (estradiol benzoate 1 mg s.c. twice a week for 4 weeks, 40 rats): microsphere uptake--density, microsphere uptake--ash weight, blood flow--density, in exp. D (20 oophorectomized females on estradiol): microsphere uptake--ash weight, blood flow--ash weight. The results support the hypothesis of an interconnection between the mineralization of bone tissue and local bone blood flow.

The authors present their experience with enzyme therapy--the preparation Wobenzym--in comprehensive treatment of supracondylar fractures of the humerus in children. On monitoring the condition of the extremity by Doppler ultrasound, where the flow through the radial artery was quantified they obtained better results in the group of patients treated by systemic enzyme therapy than in the control group. Systemic enzyme therapy is recommended as a suitable supplement in comprehensive treatment where the most important part is played by correct and early treatment along with precise monitoring of the extremity during the postoperative course.

Relatively rare high-flow priapism is most frequently caused by contusion or direct injury of the cavernous artery with a subsequent uncontrolled inflow of arterial blood into the cavernous bodies. Knowledge of this pathophysiology and the development of intervention radiology made a more selective therapeutic approach possible. The authors present a report on a case of arterial or high-flow priapism which was successfully resolved by a minimally invasive approach--percutaneous superselective transcatheter embolization of the internal pudendal artery.

Between December 1993 and October 1996 the authors performed laparoscopic operations of varicocele in 75 patients incl. 53 for concurrent subfertility. In all patients before operation by Doppler sonography and coloured Doppler mapping venous reflux was detected. The volume of the testis was also assessed by sonography. In subfertile patients changes of the spermiogram were assessed. After operation the blood supply was evaluated (the resistive index), the volume of the testes, the duration of the operation and changes in the spermiogram. The authors did not detect a significant difference between the group of 27 patients where with the vein also the artery was ligatured and the group of 48 patients where only the vein was ligatured. The patients were not damaged by ligature of the artery.

Dehydroepiandrosterone (DHEA) is a steroid with important effects on the bone tissue. We tried to check up if it influenced also the bone blood flow (similarly as estradiol and testosterone). We administered DHEA (Sigma) dissolved in dimethylsulphoxide s.c. three times weekly for four weeks in the doses of 15-20 mg per rat on 125 mg/kg body weight to female rats--sham-operated or oophorectomized (OOX). In two experiments (A and B) we ascertained the uptake of 85Sr-microspheres, local blood flow, cardiac output, density and ash weight of the burned tibia, in the third experiment (C) 24 hour incorporation of 45Ca and 3H-proline into the bone. The 85Sr-microsphere uptake in the tibia was elevated after OOX in both experiments A and B; this increase was inhibited completely (and statistically significantly versus the OOX group) by the administration of DHEA. Similar and also significant reactions were found in the microsphere uptake values in the distal end of femur. No significant changes could be demonstrated in the diaphysis of femur and calvaria as well as in the cardiac output, output, blood pressure and heart rate. The incorporation of 45Ca and 3H-proline into the tibia (experiment C) was significantly increased after OOX. The administration of DHEA inhibited this increase significantly in the values of 3H-proline. The density of tibia in both experiments A and B and ash weight of tibia in experiment A, suppressed after OOX, were significantly increased after the administration of DHEA to OOX females. The results show that also DHEA--in the experimental conditions used--has similar effect on the bone blood flow as estradiol and testosterone.

EDRF-NO probably participates-besides the prostaglandins [3, 4]-in local circulatory changes in the bones of female rats with modified level of sex hormones; we could demonstrate it indirectly using methylene blue as a blocking agent [5]. In this paper, we present corresponding results of two experiments with NG-nitro-arginine methyl ester (L-NAME) as a substance blocking the production of endothelium derived relaxing factor, i.e. nitric oxide (EDRF-NO). Circulatory values were estimated by means of 85Sr-microspheres. In experiment A we ascertained whether the duration of L-NAME administration (0.025% in the food) influenced the effect. It could be demonstrated that the effect of one week's, two weeks', or four weeks' administration of L-NAME was the same: 85Sr-microsphere uptake and blood flow throught the tibia of female rats, increased after oophorectomy (OOX, performed four weeks prior to the experiment), was significantly suppressed to the level in sham-operated animals. In the experiment B, L-NAME was administered in the food in concentration of 0.05% for two weeks prior to the experiment. 85Sr-microsphere uptake was decreased significantly after L-NAME in the tibia of sham-operated females, in the tibia and distal femur of OOX animals; no significant changes were found in the diaphysis of femur and in calvaria. Blood flow values were significantly decreased in all bone samples of OOX females and in tibia of sham-operated rats (besides the local reaction also due to the decrease in the cardiac output). In both experiments the cardiac output was decreased and blood pressure elevated after L-NAME. It can be concluded, from the results of both experiments, that the blockade of EDRF-NO production by L-NAME decreases local circulatory values in the bones of female rats-particularly OOX-in a similar way as methylene blue; however, in contrast to methylene blue, L-NAME induces marked increase in the blood pressure and partially decrease in the cardiac output. Thus, as in the case of methylene blue, the effect of L-NAME on the circulation of blood in the rat bones supports the hypothesis of the participation of EDRF-NO in bone blood flow regulations.

In a short communication we demonstrated the inhibitory affect of acetylosalicylic acid (ASA) on the increased bone blood flow and 45Ca and 3H-proline incorporation in oophorectomized (OOX) female rats. This finding suggested probable participation of prostaglandin. The aim of the present work was to confirm and extend the initial observation and to find out, whether the administration of ASA did not affect also the decrease in the bone blood flow after the administration of estradiol benzoate (EB). Local blood flow was determined by means of the uptake of 85Sr-microspheres. In experiment A (females) the local circulatory values were increased after OOX significantly in tibia and distal femur, insignificantly in diaphysis of the femur and calvaria; this increase after OOX was suppressed by simultaneous administration of ASA completely in tibia, partially (and statistically insignificantly) in distal femur and diaphysis of the femur; no effect of ASA could be demonstrated in the calvaria. The blood flow through the kidneys of OOX female rats was decreased after ASA, while no change occurred in muscle and skin. The bone mineral content was significantly lower in both groups of OOX females. In experiment B (males), we observed an increase in local circulatory values after ORX in tibia, distal femur and diaphysis of the femur and suppression of this increase by the administration of ASA. These changes were not demonstrable in the calvaria and soft tissues studied. In experiment C (females), we found that significant decrease in the local circulatory values in the tibia after 4 weeks of administration of EB was not altered by simultaneous administration of ASA. Experiment D (females) proved again that 24 hour incorporation of 45Ca and 3H-proline was markedly suppressed by the administration of ASA not only in OOX females but also in sham operated control rats. Thus, the present results confirm the inhibitory effect of ASA on the increase in bone blood flow after castration, indicating with high probability participation of prostaglandin (PGE2?) (while no effect of ASA could be demonstrated on the decrease in bone blood flow after EB). The described blood flow changes are induced by local vascular reactions and occur in the bones of both female and male rats. Marked suppression by ASA of 45Ca and 3H-proline incorporation supports the circulatory results and indicates an important interconnection between metabolic processes and local circulation in the bone. We conclude that prostaglandin may be one of the factors regulating bone blood flow.

Measurements of hemodynamics in parodontium and gingiva using a reflexive photoelectrical plethysmographic recorder, insensitive to salivation changes, has been described. Registration is accomplished by means of ECG recorder.

In the experiments on rats, the bone blood flow may be influenced by the deficiency as well by the administration of sex hormones. The aim of this work was to investigate the bone circulation (determined by means of 85Sr-microspheres, experiment A and B) and the incorporation of 45Ca and 3H-proline into the tibia (experiment C) in the last stage of pregnancy (from 18 to 21 days), i.e. in the physiological condition with elevated level of estrogens. In the experiment A and B, the uptake of 85Sr-microspheres and blood flow in pregnant rats was lower in the tibia and distal femur, the blood flow only was significantly lower also in the humerus and the calvaria. In kidneys, liver, muscle and skin, there was no difference in microsphere uptake; the blood flow was in pregnant females lower only in the kidneys. In perirenal fat, the microsphere uptake and blood flow was several times higher in pregnant rats than in controls. 24 hour incorporation of 45Ca and 3H-proline was in pregnant females significantly lower. The bone density and ash weight was higher in pregnant rats in experiment A. Estradiol concentration in plasma was in experiment B in pregnant rats significantly higher (by 24.8%). Thus, in pregnant female rats, we found lower bone blood flow and lower incorporation of 45Ca and 3H-proline along with normal or higher bone mineral content in the condition, where enhanced resorption and formation of the bone had been described. The changes in bone blood flow and possible role of estrogens in this situation remain to be elucidated.

The author evaluates the possibilities of coloured Doppler vaginosonography for prebioptic evaluation of the nature of ovarian tumours. He investigated the site of vascularization of tumours and qualitatively the blood flow by assessing the vascular resistance (PI, RI) and character of the flow velocity curve. The results revealed a statistically significant (por = 0.05) trend of central vascularization of malignant tumours. A new parameter with a 100% sensitivity and 89% specificity proved to be the notch at the beginning of the diastolic part of the velocity curve which was not observed in any carcinomas but was present in 89% of benign lesions. The vascular resistance was significantly lower in malignant tumours. The cut off value of malignity of the pulsatility index PI = 0.7 had a 86% sensitivity and 100% specificity. The cut off value of the resistance index RI is 0.6 with a 100% sensitivity and 75% specificity. Comparison of the predictive values of malignity of conventional and coloured duplex ultrasonography revealed that for evaluation of the nature of ovarian tumours coloured duplex sonography with several parameters is more suitable. PI and RI alone can be considered rather as indicators of active growth.

Haemodialysis patients with chronic renal failure suffer not only from thromboses of the vascular access but frequently also from atherosclerosis with thrombotic complications. Knowledge of the etiopathogenesis of thrombotic complications in haemodialysis patients are incomplete. The aim of the present study was to evaluate fibrinolysis at the level of plasminogen activation under conditions of a dynamic test, using methods which reflect sensitively and specifically the activity of the tissue-type plasminogen activator (t-PA) and the activity of the inhibitor of the tissue-type plasminogen activator (PAI-1).The group of examined subjects was formed by 16 patients (9 men and 7 women, mean age 42 years, range 26-63) who suffered from chronic renal failure (causes: 9x chronic glomerulonephritis, 6x interstitial nephritis, 1x polycystic kidneys) treated by long-term haemodialysis on average for 52 (20-110) months; the control group of 11 healthy volunteers was very close as regards age distribution. t-PA and PAI-1 were examined after stimulation by venous occlusion (VO). In healthy subjects VO significantly raises the t-PA activity (first value before, second after VO: t-PA 0.81-2.19 IU/ml, p0.01), specific t-PA activity (0.19-0.31 IU/ng, p0.05) and t-PA/PAI (0.06-0.24 IU/U, p0.01, decreases PAI activity (11.80-10.98 U/ml, p0.05) and specific PAI activity (0.52-0.40 U/ng, p0.01). In the group of haemodialysis patients VO did not change significantly the t-PA activity (p = NS), the specific t-PA activity (p = NS), nor the ratio of t-PA/PAI (p = NS); the PAI declined significantly (13.78-10.65 U/ml, p0.05), similarly as the specific PAI activity (0.97-0.65 U/ng, p0.01). From comparison of the results of fibrinolysis from healthy and dialysis subjects ensues that the response to VO in dialysis patients differs from that in healthy subjects.Dialysis patients have impaired fibrinolysis manifested by a lacking rise of activity of the plasminogen tissue activator after stimulation by venous occlusion. The small rise of t-PA activity after venous occlusion can contribute to the development of thrombotic complications in haemodialyzed patients.

From a total of 2,312 Doppler examinations made in 1992 at the Gynaecological Department of the University Clinic in Zürich in 34 patients in the 3rd trimester of pregnancy a lateralized pathological blood flow in the uterine artery on the non-placental side was found. As a control group the authors selected a group of 34 patients comparable as to age, gestation period, time when the Doppler examination was made and the type of delivery. The results of the investigation are not statistically significant in view of the low percentage incidence of lateralized pathology, however, it may be stated that the finding may be the first symptom of incipient foetal hypoxia.

The author assumes that the process of the adjustment of the disproportion between the arterial and the venous volume can be favourably influenced by a decrease in the offered arterial volume to the venous occluded blood path. This can be achieved by a narrowing of the input arteriole with the help of the method of arteriolar constriction using the argon laser. The author is of the opinion that the method of arteriolar constriction finds its application especially in the treatment of severe prognostically unfavourable forms of occlusion of the branch of the retinal vein with presence of extensive hemorrhages in the retina. In such severe forms of occlusion, the author recommends to apply the arteriolar constriction already in the early acute phase of the disease.

In the pathogenesis of macular edema in venous occlusion of the retina, the majority of authors considers the high intracapillary pressure to be the decisive factor. The author's explanation is somewhat different and is based on two assumptions. The existence of the vascular autoregulatory mechanisms of the retina and the so-called disproportion between the arterial and the venous volume. When the critical level of the disproportion of the arterial and the venous volume is surpassed, the retinal autoregulation begins to fail which manifests itself by a marked retinal edema and an essential decrease in visual acuity.

Four experiments on 76 female and 79 male rats were performed in which we followed up the effect of four weeks' administration of estradiol benzoate (Agofollin Depot 1 mg per rat once a week or 5 mg per kg once every 5 days s. c.) and testosterone isobutyrate (Agovirin Depot 25 mg per kg once every 5 days s. c.) on the local circulation in the tibia and distal femur (by means of 85 Sr-microsphere uptake) and on bone density and ash weight related to bone volume. Local circulatory values increase in the bones after oophorectomy (OOX) and orchidectomy (ORX) and decrease after estradiol in sham-operated rats of both sexes; testosterone inconstantly reduces the 85Sr-microsphere uptake in the bones of sham-operated male rats. Estradiol decreases local circulatory values in OOX females and ORX males to the level observed in sham-operated animals. Testosterone has a similar inhibitory effect in ORX males as estradiol; less pronounced, but statistically significant lowering occurs also in the tibia of OOX females. Density of the tibia and ash weight related to bone volume unit falls after OOX and ORX and rises constantly after estradiol; after testosterone administration, it does not change in sham-operated rats and OOX females, but rises in ORX males. Probably the most important finding is that also testosterone reduces local circulation in the bones of rats, though less regularly and less markedly than estradiol (in the dosage used).

After six weeks' administration of estradiol benzoate (Agofollin Depot, 1 mg s.c. once a week) we determined in the first part of 70 days old female rats the uptake of 85Sr-microspheres and local blood flow in the tibia, in the second part 24 hours' incorporation of 45Ca and 3H-proline and in the third part 2 hours' uptake of 85Sr, bone density and ash weight related to 1 ml of bone volume. We observed the following statistically significant changes: decrease in the uptake of 85Sr-microspheres and local blood flow, decrease in the incorporation of 45Ca, 3H-proline and 85Sr, increase in the density and ash weight of the tibia. The rise of bone mineral content simultaneously with reduced indicators of bone formation and particularly of the mineralization seems to be in the connection with the suppression of bone resorption under the influence of estrogen. Qualitatively identical reactions of circulatory and metabolic indicators to the administration of estradiol may be a reflection of mutual physiological interconnections.

In an experiment on 38 75-day-old female rats--sham-operated or oophorectomized (OOX)--the authors assessed the effect of hydrocortisone administration (0.01% in the diet for four weeks) on the blood flow in the tibia and distal end of the femur (uptake of 85Sr microparticles). In the tibia they assessed also the density (according to the Archimed principle) and the weight of ashes per volume unit of bone. OOX increases significantly local circulation in both bones. After hydrocortisone these values are significantly lower in sham-operated and OOX rats as compared with controls and also significantly lower in the group OOX+hydrocortisone, as compared with group OOX. The density and weight of ashes from the tibia are not affected by hydrocortisone; the minute volume of the heart per 100 g body weight of rats is not altered in any group. The mechanism of the described hydrocortisone effects on circulation is not known. In the discussion the authors indicate possible associations of blood flow and the osteoblast and prostaglandin function in bony tissue.

In a long-term experiment on dogs the lumen of the portal vein was reduced to one fifth by insertion of a metal spiral. The thus created disorder of the portal circulation was succeeded by the development of abundant hepatofugal collaterals and the development of mild portal overpressure without clinical manifestations. The altered portal circulation was followed up by dynamic hepatobiliary scintigraphy for a period up to 12 months. It was revealed that the curve of isotope movement through the liver was altered in a way suggesting slower perfusion of the liver by portal blood. This observation resembles those in patients with prehapatic portal hypertension and their confirmation. The investigation is documented by morphological, X-ray and isotope methods.

The authors assessed in 12 patients with compensated cirrhosis of the liver, portal hypertension and oesophageal varices, using a Doppler flowmeter Toshiba SAL 50A/SDL 01 under basal conditions, changes in the width, rate of blood flow and blood flow though the trunk of the portal vein before and after intravenous administration of 1 mg glucagon. The width of the trunk of the portal vein did not change significantly during assessment. A statistically significantly increased flow through the portal vein was recorded starting during the 5th minute, and it correlated with the increased velocity of the blood flow. The increased flow persisted to the 20th minute after glucagon administration. The drop of pressure in a wedged position assessed in the hepatic veins after administration of the drug was not significant, the pressure in the free hepatic vein increased insignificantly. On the whole the portohepatic gradient declined by 10.5%, the drop was not significant. Glucagon in pharmacological doses has an early onset of action even in cirrhotic subjects whereby the increased flow through the portal vein does not lead to a rise of the portohepatic gradient. Glucagon administration thus does not increase the risk of haemorrhage from oesophageal varices during acute fibroscopy of the oesophagus and stomach in patients with portal hypertension.

In previous experiments (4) we observed in laboratory rats after a low Ca content diet with no vitamin D a decrease of blood flow through bones. In this study we follow whether the effect of the deficit diet is influenced by age or sex of experimental animals. Tibia blood flow in rats is established by 85Sr-microparticles, bone density is estimated by weighing the bone under water. After 10 days of feeding by the deficit diet 85Sr-microparticles catchment in young males is decreased to 74% of that of controls, in young females to 61%, blood flow is decreased to 46% and 51% respectively. In older males after the diet the microparticles catchment is significantly decreased to 63%, blood flow is non-significantly decreased to 82% (as a result of higher cardiac output). In the category of older females the effect of deficient diet is not demonstrable as regards both microparticles catchment and blood flow. Bone density in preliminary experiment after 40 days of diet is significantly decreased in males of both age categories and in young females, in the main experiment after 10 days of diet it is decreased only in the categories of young males and females. From the results obtained in following the effect of diet deficient in Ca and vitamin D on density and local blood flow in tibia of rats can be concluded 1) that in this respect younger rats are more susceptible, 2) in the category of older males the effect is partly demonstrable in males, but not in females.