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Biomedical subjects

J Valenta

Publications and source records attributed to J Valenta.

At least 19 recordsLinked to original sources
PubMed2000

[Viper (Vipera berus) snake bites].

Cases of snake bites (Vipera berus) have as compared with past years a rising trend in the Czech Republic. This ensues among other factors from a higher prevalence of snakes due to the improving ecological situation. The morbidity of snake bites is of no epidemiological importance, the frequency of snake bites amounts to several tens per year and in some clinically manifest intoxication does not develop. Nevertheless in individual cases, in children weakened subjects, a viper bite may be manifested by a serious and in exceptional instances fatal affection. Within the framework of first aid the authors do not recommend application of a tourniquet or dissecting of the wound because of undesirable potentiation of tissue traumatization. Non-specific treatment involves the administration of corticoids and antihistaminics. Specific immunotherapy, administration of horse antiserum (Ipser Europe, Pasteur Mérieux, France) is indicated only in case of systemic or very severe local symptoms and is associated with the risk of a severe allergic reaction. In case of severe systemic symptoms, symptomatic treatment in a health institution of the appropriate type is of fundamental importance. In all cases observation of the affected subject is recommended to rule out intoxication or the development of possible complications.

Adult↗
PubMed2000

Endogenous fibrinolysis in patients with lower extremity ischemia.

To explore the relationship between disorders of endogenous fibrinolysis and thrombosis in patients with lower extremity ischemia, we measured the activity of tissue plasminogen activator (tPAac) and plasminogen activator inhibitor (PAlac) and the antigens of tissue plasminogen activator (tPAa) and inhibitor (PAla) in plasma from 420 patients treated for lower extremity ischemia. Values and ratios observed were compared with those in healthy volunteers. Additionally, values and ratios in the patients were examined with respect to the severity of ischemia and site of atherosclerotic occlusion or stenosis (pelvic compared with femoropopliteal or crural). Patients with lower extremity ischemia had higher plasma concentrations of PAla (p<0.01) and PAlac (p<0.0001) than healthy volunteers. In patients with rest pain or gangrene, the ratio of tPAac to PAlac was higher than in patients with claudication (p<0.05). The elevation of tPAac in patients with the more severe form of lower extremity ischemia is probably the feedback protective reaction on prothrombotic mechanisms of the organism suffered from severe atherosclerosis. Results did not vary according to the site of occlusion or stenosis. Our study found defects in endogenous fibrinolysis in patients with lower extremity ischemia. A defect in fibrinolysis may contribute to the development of thrombosis in native arteries and bypasses.

Adult↗
PubMed2000

[Prevention of venous thromboembolism].

Deep venous thrombosis and pulmonary embolism, the epidemiologically most important forms of thromboembolic disease still remain one of the most serious problems in medicine. The authors summarize some epidemiological data, the incidence and risk of the disease with regard to the patients condition and the type of insult. The authors mention possible methods of non-specific prevention, types and effectiveness of specific primary and secondary pharmacoprophylaxis and describe physical prophylactic methods. The review offers recommendations for prevention with regard to the assessed risk of the patient and type of insult with special attention to the use of nadroparine.

Anticoagulants↗
PubMed1999

Plasma endothelin levels in patients with abdominal aortic aneurysms.

OBJECTIVES: endothelin 1,2 plays a significant role in the process of atherogenesis and vascular wall injury. The aim of this study was to assess whether plasma endothelin 1,2 levels were elevated in patients with large or symptomatic abdominal aortic aneurysms (AAAs). DESIGN: a prospective open study. MATERIALS AND METHODS: plasma endothelin 1,2 levels were measured in 65 consecutive patients with infrarenal aortic aneurysms and compared with the levels in 44 healthy volunteer controls. The data for abdominal aneurysm patients was analysed in four subgroups: (i) small aneurysms (<5 cm), (ii) large aneurysms (>/=5 cm), (iii) asymptomatic aneurysms and (iv) symptomatic aneurysms. Comparisons were made between endothelin 1,2 levels in aneurysm patients and controls and between the different aneurysm subgroups. RESULTS: a highly significant difference (p<0.0001) was found between aneurysm patients and controls. Patients with large aneurysms had significantly higher levels than patients with small aneurysms (p<0.01). There was no statistical difference in endothelin 1,2 levels between symptomatic and asymptomatic patients; however, the highest levels were found in large, symptomatic aneurysms and the lowest in small, asymptomatic aneurysms. CONCLUSIONS: plasma endothelin 1,2 is an endogenous marker of aneurysm diameter. Further studies are required to determine whether it relates to the rate of growth of aneurysms.

Aged↗
PubMed1999

[Ethical problems in organ transplantation].

Organ transplantation is an accepted therapeutic method with good results, but it is connected with many not only medical but also ethical problems. One of the most important problems is the donor programme. In cadaverous donors the main ethical and legal question is the decision who can issue the consent with organ retrieval; in living donors it is the problem of motivation and financial compensation. Allocation of organs with low compatibility or from non-ideal donors, and the recipient's consent in these cases may involve difficult decisions.

Ethics, Medical↗
PubMed1999

Residual strain in human atherosclerotic coronary arteries and age related geometrical changes.

The opening angles of 16 rings excised from human coronary arteries with different degrees of atherosclerosis were determined 10 hours after death. Atherosclerosis, as a chronic inflammatory response of arterial endothelium and intima, is defined by three degrees of its development. The opening angle decreases more or less linearly with the distance from the right coronary artery orifice. This is in accordance with the functional requirements posed on blood transport into the coronary arteries. A decrease of the opening angle with age is affected by hardening of the arterial wall, among other factors. This is in accordance with a stochastic model of age related changes in the initial modulus of elasticity of the coronary artery. A part of the free energy of smooth muscle cells, fibroblasts, collagen and elastic fibres is used not for creating residual strain but for remodeling the arterial wall structure. The opening angle is also considerably affected by the degree of atheroclerosis. The dependence on age of the external diameter and the thickness of the intact left and right coronary arteries in the vicinity of the aortic sinus was also analyzed in two female and two male subjects. To ensure the objectivity of the results it is necessary to carry out additional experiments and studies in vivo.

Adolescent↗
PubMed1998

Role of crossover bypasses in the treatment of ischemia of the lower extremity.

AIM: To evaluate the role of crossover bypasses in the treatment of the lower extremity ischemia. METHODS: A retrospective study (1978-1997) included 51 patients with 52 femoro- or iliofemoral crossover bypasses. The most frequent indication for crossover bypass was unilateral thrombotic occlusion of the bifurcated graft or unilateral pelvic occlusion (49.0%) and the rest pain (40.4%). The main type of crossover reconstruction was "U" shaped, subcutaneous femorofemoral bypass. The first, third, and fifth year primary patency rates were evaluated using the life table analysis method. RESULTS: The cumulative patency rates were 91.3%, 73.9%, and 54.5% at 1, 3, and 5 years, respectively. Limb amputation had to be performed in five (9.6%) failed reconstructions. In four (7.7%) cases, thrombosis of reconstruction, and in one (1.9%) case, graft infection, caused the bypass occlusion. One patient (1.9%) died within 30 days after surgery from an acute myocardial attack. CONCLUSION: Crossover bypass is an attractive method because of its technical simplicity, low morbidity, and good long-term results.

Aged↗
PubMed1997

[Clinical spectrum of the antiphospholipid syndrome].

Antiphospholipid syndrome (APS) is characterized by multiple arterial and venous thromboses, repeated spontaneous abortions and thrombocytopenia, together with the presence of antiphospholipid antibodies in serum. We present three patients, two men and a woman, at the age of 43, 24 and 23 years respectively. The younger man and the woman had secondary APS and systemic lupus erythematosus, the older man had primary APS. The symptoms and course of the disease were different. The older man lives 17 years after the onset of first symptoms with multiple neurologic disorders, the younger man is symptomless. The woman died several months after the acute onset of the disease.

Adult↗
PubMed1997

[Intubation of afferent lacrimal ducts--a review of techniques].

The authors present a review of various techniques of long-term intubation of efferent lacrimal pathways by a silicone fibre. They use an original way of intubation and intubate the insertion probes of the intubation set from the lower nasal outlet by means of a titanium loop under direct optic control by means of an endoscope. The use of the endoscope makes it possible to reduce the number of complications and iatrogenic damage of the mucosa and it enhances the effectiveness of the procedure. The authors prefer the use of special intubations sets; for young children intubation sets made from soft metal are preferable. At present all their demands are met by the intubation set they developed in collaboration with the Technical University, Prague. During the period between April 1994 and August 1996 the authors used the described technique for bicanalicular intubation of the efferent lacrimal pathways in 127 children and in adult patients 6x. In 86 instances they used an intubation set of Geuder Co., 44 times their own intubation set.

Adult↗
PubMed1997

[Extensive metastases in the thoracic wall as an unusual manifestation of malignant hepatoma].

In a 53-year-old man an extensive tumour of the thoracic wall was extirpated. It was examined histologically and identified as a secondary of a malignant hepatoma. In the second stage a primary hepatic tumour was removed by extended right-sided lobectomy. The case-history provides evidence of a remote secondary of a malignant hepatoma and a successful palliative approach.

Carcinoma, Hepatocellular↗
PubMed1997

Residual stresses in the human aorta and their influences by growth and remodelling.

The aim of the present work is to demonstrate of the influence of the adventitia on distribution of residual stresses in the human aorta. The biomaterial increase in media as well as in adventitia in the course of the aorta's growth is formed by an intussusceptive mechanism of growth. In children's aortas, formative elastin lamellae are wavy with high amplitude perpendicular to the aortic surface. In adults' aortas the waves become smoother (stepwise) towards the adventitia. Also introduced is the growth function, which characterizes the biomaterial growth and the interference between the media and adventitial layers. It is possible to expect an extraordinary variability in the formation of the aortic wall tissue in the course of its growth as a result of metabolic and humoral influences and magnitude of the residual stresses in the course of growth.

Adult↗
PubMed1997

[Aneurysms of the abdominal aorta].

The authors present the experience of the Plzen department with treatment of aneurysms of the abdominal aorta (AAA) during the last five-year period (1992-1996) when they operated a total of 111 AAA in patients with an average age of 67.9 years (44-91 years). The number of symptomatic AAA was 15 (13.5%), 36 ruptures (32.4%). The most frequent risk factor was ischemic heart disease (IHD) in 74 (66.7%) and hypertension in 47 (42.3%) of the patients. Within 30 days after surgery two asymptomatic patients died (3.9%) and three (20%) with symptomatic AAA. The most frequent cause of death was acute myocardial infarction (AIM) in four (80%). Of 36 patients with rupture of AAA 17 (47.2%) died. A statistically significant factor for death of patients with rupture of the AAA was sever shock (blood pressure < 40 mm Hg) before surgery (p < 0.01), blood in the abdominal cavity (p < 0.01) and hypertension in the patient's case history (p < 0.05). Aimed screening of AAA in patients of risk groups and early elective surgery are important for reducing the incidence of ruptures of AAA. A patient with rupture of the AAA needs surgery urgently and unnecessary examination (CT, USG) frequently causes delay and reduces the patient's chance of survival.

Adult↗
PubMed1997

[Role of pulse spray thrombolysis in acute ischemia of the extremities--comparison of results with the low dose technique of local thrombolysis, embolectomy and thrombectomy].

BACKGROUND: The reported mortality of patients suffering from acute limb ischemia is in the range of 10% to 30%, as is the incidence of amputation in the survivors. MAIN PURPOSE: The evaluation of the pulse spray thrombolysis (PST) role in the treatment of acute extremity ischemia originating from thrombosis or embolism of native artery or bypass graft. The comparison of PST with low dose technique thrombolysis (LD), thrombectomy (TE) and embolectomy (EE). METHODS: Ninety nine consecutive patients were evaluated during a two year interval (1994-1996). PST, resp. LD, TE and EE were the method of choice in 22, resp. 11, 35 and 31 patients of average age 58.3 +/- 13.7; resp. 60.0 +/- 8.9; 74.2 +/- 11.7; 76.9 +/- 9.3 years. The native artery was occluded in 15 (68.2%), resp. 8 (72.7%), 31 (88.6%) and 30 (96.8%) patients with PST, resp. LD, TE and EE treatment. The vascular reconstruction was occluded in the rest of the cases. The lower limb extremity arteries were occluded in 20 (90.9%) of patients indicated for PST, 10 (90.9%) for LD, 33 (94.3%) for TE and 26 (83.9%) for EE. The contraindication for local fibrinolysis was severely ischemic limb in which viability was imminently threatened. RESULTS: PST was successful in 19 (86.4%), LD in seven (63.4%), TE in 13 (37.1) and EE in 27 (87.1%) patients. The failure of procedure required amputation in one patient (4.5%) with PST, one (9.1%) with LD, nine (25.7%) with TE-p < 0.001 and two (6.5%) with EE. The mortality was 4.5% (one patient), resp. 0%, 28.6% (10 patients)-p < 0.001 and 3.2% (one patient) in PST, resp. LD, TE and EE. The long term results were better if the successful local fibrinolysis was combined with percutaneous transluminal angioplasty (PTA), stent implantation or small vascular reconstruction. CONCLUSION: PST is the method of choice in the treatment of thrombotic or embolic occlusion of native artery or bypass graft in condition of good limb viability where there is no danger of time delay. EE is indicated in limb embolism where the viability of extremity is threatened. Thrombectomy alone has no place in the treatment of artery or bypass graft thrombosis.

Embolectomy↗
PubMed1996

[Use of endogenous proteins in the early diagnosis of dysfunction in transplanted kidneys].

The early diagnosis of renal allograft dysfunction in the immediate posttransplantation period is very important. The prospective study was undertaken in 60 patients after kidney transplantation. The significance of blood and urine levels of glomerular and tubular proteins was studied for early diagnosis of allograft dysfunction. The authors evaluate some glomerular (CRP, transferrin, immunoglobulins) and tubular (alfa 1 microglobulin and beta 2 microglobulin) proteins for differential diagnosis of acute tubular necrosis and acute rejection of transplanted kidney.

Adult↗
PubMed1994

Modelling tissue behaviour based on hyperelasticity theory.

The tissues are during their physiological function, e.g., in the course of growth, adolescence, and aging, subjected to a cyclic mechanical loading and to large displacements and rotations as well. A tissue free of all external tractions is in a state that minimizes its internal power. In the course of aging of the tissues, for instance in the wall of the aorta, the vein, and also in the myocardium or heart valves, the decrease of the water content and increase of the collagen content occurs; while in compact and trabecular bone the contents of both mineral substances and collagen, undergo reduction. In accordance with it, the strain energy function and the constitutive equations of living tissue based on the hyperelasticity theory using rotationless strain were studied. On the base of the proposed eigenvalue decomposition of the rotationless strain tensor and hyperelasticity the strain energy function was formulated as depending on biological time of tissue. The quantity of strain energy function per unit of the biological time, which essentially characterizes the velocity of change of mechanical response of tissue in the course of its aging, was also defined. The coefficient of tissue aging is the further diagnostic parameter, which is independent of the rotationless strain tensor and expresses the relative change of mechanical response of tissue during the biological time. The corresponding constitutive equation of tissue depending on the biological time is also determined. On the base of the regression analysis the theoretical stress-strain curves for myocardium and blood vessels were determined. The numerical results reveal that the coefficient of aging progressively increases in hardening tissues (coronary artery, vena cava inferior) whereas at the softening tissues it has a relatively slow increase at the dependence on tissue aging.

Adolescent↗
PubMed1994

[Continuous ambulatory peritoneal dialysis--an effective method of treatment in chronic renal failure].

The authors evaluate the results of treatment of continuous ambulatory peritoneal dialysis (CAPD) in seven patient with chronic renal failure during a 12-month period. The baseline examination was made one month before CAPD was started, one day before insertion of a Tenckhoff catheter and then after 1, 3, 6 and 12 months of treatment. The highest assessed mean serum urea concentrations during treatment were 19.8 +/- 2.3 mmol/l (arithmetic mean +/- SE of the mean), creatinine 815.1 +/- 43.1 mmol/l. The haematocrit improved significantly due to CAPD. From the mean value of 22.5 +/- 1.7% recorded one month before treatment it increased to 32.8 +/- 2.5% after 12 months of therapy. In five patients CAPD made it possible to discontinue and in two to reduce antihypertensive medication. During the investigation period the authors did not detect a drop of total protein and albumin in serum. Serum cholesterol increased significantly during treatment. Peritonitis was recorded four times during the total period of 70 months of treatment, i.e. on average one episode during 17.5 months of treatment. Based on their results the authors conclude that CAPD is at present one of the very effective methods of treatment of chronic renal failure. The incidence of peritonitis was already during the first year when treatment was initiated comparable with the results in departments where it is commonly used and after further experience it declined to one episode per 38.8 months of treatment. The method deserves wider application than hitherto.

Adult↗