Biomedical subjects

J Krivánek

Publications and source records attributed to J Krivánek.

At least 19 recordsLinked to original sources

PubMed2006

[Pulmonary endarterectomy--the surgical treatment of chronic thromboembolic pulmonary hypertension].

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) in indicated cases can be successfully treated by the endarterectomy of pulmonary arteries (PEA). Symptomatically not treated CTEPH has highly unfavourable prognosis. Five years survival of patients with mean pulmonary pressure over 50 mmHg is only 10%. PEA was not available in the Czech Republic till 2004, when PEA program was initiated it the Cardiocenter of the General teaching hospital in Prague in collaboration with leading clinics in that field (Prof. Mayer, University of Mainz, BRD). METHODS AND RESULTS: Up-to-date surgical technique, which in various modifications has been used at majority of clinics, was elaborated by Jamieson and Daily at University of California in San Diego. It is based on reverse endarterectomy performed during complete circulatory arrest with brain protection by deep hypothermia. Till September 2005 twelve patients were operated with zero mortality. In one patient a suture of atrial septum defect was necessary to perform along. Average time of the circulatory arrest was 45 minutes; duration of the extracorporal circulation was 334 minutes. Average duration of the operation was 450 minutes. Duration of the mechanical ventilation was in average 45.5 hours. After one month already haemodynamic parameters (mPA, CI, PVR) significantly improved or normalized and the average length in the test of six minutes walking increased by 132 meters. CONCLUSION: PEA represents a treatment method for patients with CTEPH and surgically accessible pulmonary artery obstruction. Centralized care of those patients is a rational necessity enabling to get maximum experience with complicated diagnostics and treatment of those patients. Multidisciplinary collaboration is the essential condition for the success of the program.

Adult↗

PubMed2005

[Liver abscesses with portal and mesenteric vein thrombosis in combination with late onset of appendicitis].

Pyogenic liver abscesses are caused by appendicitis in less than 10%. Also the ascending septic inflammation of portal vein (pylephlebitis) could be a serious complication of intra-abdominal infection. Although pylephlebitis is not frequent today, its' mortality and morbidity rates remain high. We describe a case of young man with fever, abdominal pain, and multiple hepatic abscesses. After the symptomatic relief due to antibiotic therapy the pain returned as a result of the development of portal and mesenteric vein thrombosis. The cause of either hepatic abscesses or thrombosis was not clear at the time of dismissal. 2 months later the patient underwent acute abdominal revision with appendectomy for acute phlegmonous and gangrenous appendicitis. Since that time he has been without any clinical symptoms.

Abdomen, Acute↗

PubMed2005

[Embolization of uterine arteries during myoma treatment from the patient's point of view].

OBJECTIVES: To acquire information about the patient's follow-up evaluation of treating fibroids by uterine artery embolization (UAE). DESIGN: A retrospective multicenter clinical trial. SETTING: Department of Obstetrics and Gynaecology, 1st Faculty of Medicine and the General Faculty Hospital, Charles University, Prague. METHODS: 45 women who underwent the UAE due to uterine fibroids from 1999 to 2003 were asked to complete a questionnaire. The questionnaire included 26 questions asking how the women had been informed and what they had expected. Further questions were focused on the course of embolization itself, early post-procedural difficulties (post-embolization syndrome) and patient's overall evaluation of treatment in a longer term. Those women who had completed the questionnaire and had been ready to co-operate were thereafter examined and included in the follow-up monitoring and, if necessary, further treatment was recommended. RESULTS: Thirty one out of 45 patients from 26 to 48 years of age, who had been addressed (68.9%) answered the questionnaire. UAE was indicated 12 times (38.7%) on account of symptoms, 10 times (32.3%) because of sterility, 5 times (16.1%) as a preventive measure within the framework of family planning and 4 times (12.9%) for an asymptomatic but growing leiomyoma. Twenty seven (87.1%) women were also offered an alternative treatment, which they refused. As far as problems are concerned, 18 (58%) women described the course of treatment as corresponding with what they had expected, 5 times it was less painful, and 8 times it was worse than expected. The long-term results were considered as positive by 87.1% of responders, only 12.9% considered the treatment as failure. 5 in 11 women planning pregnancy became pregnant, 3 of them gave birth in term and 2 miscarried in the 1st trimester. CONCLUSION: From the point of view of the patients, the evaluated method proves highly successful, it is well tolerated and it involves a low risk of complications. It is not possible, at this point, however, to give an unequivocal answer to the question whether the method should also be routinely offered to women who are planning pregnancy.

Adult↗

PubMed1999

[Incarcerated Waldeyer's hernia as the cause of necrosis of the small intestine (case report)].

The authors present a case-record of a rare incarcerated Waldeyer hernia which became the cause of infarsation and necrosis of the free portion of the small intestine in the abdominal cavity, which developed as a result of compression of the upper mesenteric vein by the contents of the hernial sac. The authors draw attention to the asset of CT examination for preoperative diagnosis. US examination failed. They explain why, although a rare acute ileous abdomen is involved, the X-ray picture of levels on the native X-ray of the abdomen is lacking.

Adult↗

PubMed1997

[Retrograde intravenous perfusion--a therapeutic method in trophic defects of the lower extremities. Experience in patients with primary thrombocythemia].

Retrograde intravenous perfusion (RIP), so-called Bier's blockade is a relatively new method of treatment of critical ischaemia of the extremities. It is based on the principle of retrograde, i.e. transvenous perfusion of the capillary circulation during which at the time of artificially discontinued circulation in the extremities a high concentration of effective substances in the target tissues is achieved. In addition to the mentioned critical ischaemia Bier's blockade can be successfully used in the treatment of so-called "diabetic foot". It is also possible to implement by this method a local medicamentously induced block of the sympathetic nerves by administration of Guanethidine. In patients with contraindications of systemic fibrinolytic treatment local thrombolysis can be made in phlebothromboses and acral vascular occlusions. In the treatment of tumours on the extremities, e.g. melanoblastome, it is possible to achieve by local administration of cytostatics comparable results, while the incidence of undesirable effects is smaller. The objective of the present work was to make the professional public familiar with this method. On the example of four patients with trophic defects of the lower extremities which developed as a result of primary thrombocythemia the application of Bier's method was demonstrated.

Aged↗

PubMed1996

GTP, a nonsubstrate of ATP citrate lyase, is a phosphodonor for the enzyme histidine autophosphorylation.

ATP citrate lyase (EC 4.3.1.8.) was shown to be a major phosphorylation protein of a fraction derived from Zajdela rat hepatoma by chromatography on heparin-Ultrogel, after the incubation with [gamma-32P]ATP or [gamma-32P]GTP. Histidine was the only amino acid in the purified enzyme phosphorylated by [gamma-32P]ATP or [gamma-32P]GTP in the autocatalytic reaction which occurred apparently through an intramolecular mechanism regardless of a donor of phosphate. GTP inhibits the ATP-dependent autophosphorylation competitively despite its failure to replace ATP in the formation of acetyl-CoA catalyzed by this enzyme.

ATP Citrate (pro-S)-Lyase↗

PubMed1995

[Catheterization therapy of thromboembolic arterial occlusions of the lower extremities].

Thromboembolic occlusions of peripheral arteries may threaten the vitality of extremities and sometimes patients life. Till recently the main therapeutic method was Fogarty surgical thromboembolectomy. A less invasive procedure is systemic (intravenous) and local (intraarterial) thrombolysis. All these method have, however, certain disadvantages. A new approach to the treatment for acute and subacute occlusions of peripheral arteries represents catheter thromboembolectomy, which involves the following: a) Aspiration of thromboembolic material--percutaneous thrombembolextraction (PTEE), b) Local infiltration thrombolysis where the catheter penetrates through the occlusion while simultaneously administering a fibrinolytic agent, c) PTA of residual stenosis in case of thrombotic occlusion. A combination of these methods of treatment for thromboembolic occlusions of peripheral arteries is very effective and enables to use a small amount of thrombolytic agent. The thrombosis and the underlying atherosclerotic stenosis are resolved during the same session.

Catheterization, Peripheral↗

PubMed1994

Effect of vanadium ions on ATP citrate lyase.

We have shown previously that vanadium ions (vanadate and vanadyl) inhibit autophosphorylation of histidine but not that of serine in ATP citrate lyase (ACL). Here we report the results concerning the effect of monovanadate (+ oligomers), decavanadate as well as vanadyl on the activity of ACL of the rat liver. Susceptibility of ACL to inhibition by vanadate was rather low. Vanadate at concentration 10(-4) mol/l inhibited ACL by only 10% and at 10(-3) mol/l concentration monovanadate inhibited ACL by 37%. Decavanadate had comparable potency to inhibit ACL. So was vanadyl which produced 20%, 32% and 66% inhibition at 10(-4) mol/l, 10(-3) mol/l and 10(-2) mol/l concentrations, respectively. From the kinetic data it appears that inhibition by mono- and deca-vanadate of ACL with respect to both ATP and citrate was of competitive nature. Vanadyl inhibited ACL noncompetitively with respect to these substrates. However, all three species of vanadium ions inhibited ACL noncompetitively with respect to CoA. Endogenous (auto)phosphorylation of the ACL histidine as well as its response to vanadate depended on the presence of he substrate (citrate + CoA). The kinetic characteristics of vanadium ions action of ACL was compared with that previously demonstrated for vanadium inhibition of succinyl-CoA synthetase. Plausibility of our hypothesis that inhibition of histidyl phosphorylation at the catalytic site may be a common mechanism by which vanadium ions suppress the activity of the histidyl containing enzymes catalyzing the phosphoryl transfer is discussed.

ATP Citrate (pro-S)-Lyase↗

PubMed1993

[Occlusion of aorto-femoral vascular prostheses after long-term implantation].

The authors present a report dealing with their experience with reoperations for occlusion of vascular prostheses implanted in aorto-femoral region in the late postoperative period. The most frequent cause of this occlusions was the obstruction of the outflow track at the distal anastomosis. In small arteries (under 5 mm) this obstruction was mainly caused by myointimal proliferation which originated from the host artery. In the early period after occlusion it is possible to remove the thrombus from the prostheses mostly in all patients by means of Fogarty catheter and to ensure the long lasting passage of the prostheses by plastic operations of the origin of profunda femoral artery. In long lasting occlusions of the prostheses can thrombolytic therapy 1-2 weeks before reoperation facilitate removing of the thrombus. In 113 patients with the different type of reoperations for occlusion of the prostheses in the aorto-femoral region we succeeded in 102 patients (90.3%). In 8 patients the reoperation was not successful (7%) and we had to amputate the distal extremity and three patients (2.3%) died from the heart complications in the early postoperative period.

Adolescent↗

PubMed1992

Differential sensitivity of the brain ATP-dependent and GTP-dependent succinyl-CoA synthetase to vanadium ions. Developmental aspects.

We have recently found that both vanadate and vanadyl inhibit ATP-dependent succinyl-CoA synthetase (A-SCS) solubilized from the rat brain mitochondria. Aim of the present study was to estimate a proportion of A-SCS to G-SCS in adult and 5-day-old rat brain and their susceptibility to vanadium ions. The G-SCS to A-SCS ratio of 5-day-old brains was by 196% higher than that in adults. This is in accordance with previous observation that G-SCS is high in tissues metabolizing ketone bodies. Both G-SCS and A-SCS differ in their susceptibility towards vanadium ions. A-SCS of adult brain was more sensitive to vanadate (IC 50 1.6.10(-5) mol.l-1) than was G-SCS (IC 50 6.2.10(-5) mol.l-1). On the contrary G-SCS was more sensitive to vanadyl (IC 50 3.5.10(-4) mol.l-1) than was A-SCS (IC 50 9.0.10(-4) mol.l-1). Also autophosphorylation of G-SCS a-subunit was more resistant to vanadate than A-SCS. In contrast to the adult SCS forms, almost equal susceptibility of A-SCS and G-SCS to vanadyl and vanadate was observed in infant brains. The results suggest some structural (functional) differences between two SCS forms in adults and also between infant and adult G-SCS.

Aging↗

PubMed1991

A novel effect of vanadium ions: inhibition of succinyl-CoA synthetase.

Effect of vanadate and vanadyl ions on the ATP-dependent succinyl-CoA synthetase (A-SCS) solubilized by Lubrol-PX from the rat brain mitochondria was tested. Vanadate added to the assay medium at 10(-5) mol.l-1 and 10(-4) mol.l-1 concentrations inhibited the enzyme activity by about 50% and 94%, respectively. When the enzyme was solubilized from the mitochondria preincubated with 10(-4) mol.l-1 and 10(-3) mol.l-1 vanadate, the residual inhibitions were 55% and 100% respectively. The vanadyl cation also induced inhibition of the A-SCS activity but the effect was less expressed. At 10(-4) mol.l-1 concentration only 20% inhibition was achieved. The A-SCS solubilized from the mitochondrial subfractions (perikaryal, light and heavy synaptosomal) differed neither in the activity of A-SCS nor in the susceptibility toward action of vanadium ions. A strong dependence of the vanadate inhibition on the concentration of succinate was observed. The above effect (50% inhibition) could be demonstrated only at saturating concentration of succinate (50 mmol.l-1). The mechanism of vanadium ions action as well as differences between vanadate and vanadyl ions effects are discussed.

Animals↗

PubMed1991

[Atypical aneurysms of the abdominal aorta].

The authors submit a report on two patients with pseudoaneurysmatic bulging in the subrenal portion of the abdominal aorta. They present detailed histological findings in the two operated patients and discuss the aetiology of these formations. They draw attention on the failure of aortographic examinations in the diagnosis of these formations and the necessity of sonographic or CT examination. During surgery only partial resection of these formations is possible with subsequent reconstruction of the arterial circulation. The long-term results of these operations are favourable.

Aged↗

PubMed1991

[Coronary arteritis and its clinical significance].

The authors submit a report on a 47-year-old man with the syndrome of angina pectoris and history of myocardial infarction who died after a revascularization operation of the heart from left ventricular insufficiency. On necropsy extensive arteritis of the coronary vessels with aortitis was revealed and with arteritis of the small intramyocardial and lienal arteries and arteries in the renal pelvis. They describe in detail the histological finding on the blood vessels, and consistent with some data in the literature, they assume that this disease forms a separate unit. It must be considered in particular in middle-aged men who have signs of coronary ischaemia and risk factors suggesting atherosclerosis, not occur in the case-history.

Angina Pectoris↗

PubMed1990

[Arteriovenous fistula complicating central venous catheterization].

Iatrogenic fistulae are sporadic but potentially serious complications of catheterization of central veins. The authors present the case-history of a 57-year-old patient with chronic renal failure where after 19 months following temporary insertion of a central venous catheter into the subclavian vein on the right from and infraclavicular approach a continual murmur was recorded in the right subclavicular area, along with increasing manifestations of left-sided cardiac insufficiency. Using digital subtraction angiography, the authors diagnosed an arteriovenous fistula between the internal thoracic artery and the right brachiocephalic vein. The described case draws attention to a rare complication of catheterization of the central veins and its possible haemodynamic sequelae.

Arteriovenous Fistula↗

PubMed1990

[Percutaneous recanalization of the femoral artery using a laser].

The authors performed, in the period from February to May 1989 seven recanalization interventions on occlusions of femoral artery with a laser angioplasty. In six cases the dilatation of the formed primary canal was made by subsequent balloon angioplasty. In all patients the intervention was followed by a significant clinical improvement and increased doppler index. No significant clinical complications occurred during the interventions.

Adult↗

PubMed1989

[Long-term results after implantation of the femoro-popliteal vein graft in relation to preoperative values of the ankle pressure index and peroperative flow].

The authors investigated the importance of ankle pressure indices (aPi), peroperative blood flow and angiographic findings on peripheral arteries for the long-term patency of F-P venous bypasses. They found that neither the preoperative value of aPi nor the size of the peroperative flow through the bypass has an impact on the long-term patency of the reconstruction. As a result of general factors which lead to progression of the atherothrombosis in the arterial circulation in the implanted bypass, obstructions of the reconstruction occur even in patients with high preoperative aPi values and with a major preoperative flow, with patent peripheral arteries at the time of operation. To improve long-term results after implantation of F-P venous bypasses therefore above all prevention of the progression of atherosclerosis is essential.

Adult↗

PubMed1988

Do vanadium ions exert any specific effect on brain protein phosphorylation.

It has been shown previously (1) that vanadate stimulates phosphorylation of the overall proteins from the synaptic membranes of rat cerebral cortex. The aim of the present experiments was to investigate whether the action of vanadate and also of vanadyl ions could exert any specific effect on endogenous phosphorylation of proteins from subcellular fractions of the rat brain cortex. Both vanadate and vanadyl ions stimulate phosphorylation of the overall proteins from synaptic membranes and to lesser extent from mitochondria. An attempt was made to estimate the contribution of inhibition of ATPase activity to nonspecific stimulation of phosphate labeling in the synaptic membrane fraction. A band of Mr approx. 37 kDa from synaptic membranes was particularly sensitive to vanadate. In mitochondria both vanadate and vanadyl caused a marked, concentration dependent inhibition of phosphorylation of a band corresponding to Mr approx. 34 kDa. The effect was confined exclusively to the mitochondrial fractions (total, perikaryal and two synaptic types). It was absent in all subcellular fractions tested, including the nuclear one. Phosphorylation of the mitochondrial 34 kDa band is not influenced by cyclic AMP, Ca-calmodulin, shift of pH from 6.6 to 8.1. Alkaline hydrolysis removed almost all phosphate-labeled bands of mitochondria, including that of 34 kDa.

Adenosine Triphosphate↗

PubMed1988

Does vanadyl affect adenylate cyclase?

While the stimulatory effect of vanadate, an anion of pentavalent vanadium, on adenylate cyclase (AC) has been repeatedly demonstrated in various tissues only a few studies have been hitherto devoted to the effect of vanadyl, a cation of tetravalent vanadium, but these have provided contradictory results. In the present experiments synaptic plasma membranes from normal rat cerebral cortex were used for estimation of the vanadyl effect (in the concentration range from 10(-5) mol.1(-1) to 10(-3) mol.1(-1) on the basal adenylate cyclase activity. Four types of incubation media were used. In the presence of Tris-maleate and creatine phosphate + creatine phosphokinase (CP + CK) maximal stimulation (33%) was reached at 10(-4) mol.1(-1). In the same buffer but in absence or (CP + CK) maximum was already obtained at 10(-5) mol.1(-1) (49%); at 10(-3) mol.1(-1) no effect was observed. In Tric.HCl buffer with (CP + CK) maximal stimulation appeared at 10(-5) mol.1(-1), whereas at 10(-3) mol.1(-1) inhibition (-25%) was observed. In a medium containing Tris.HCl without (CP + CK) the biphasic nature of vanadyl effect was less markedly expressed: maximal stimulation (+55%) occurred at 10(-4) mol.1(-1). Thus vanadyl stimulates AC, but at relatively low concentrations (10(-5)-10(-4); at higher concentration it tends to exert an inhibitory action. Vanadate had a qualitatively similar effect, but the stimulation was more pronounced and the tendency to inhibition was shifted to higher concentrations.

Adenylyl Cyclase Inhibitors↗