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Biomedical subjects

M Simková

Publications and source records attributed to M Simková.

At least 19 recordsLinked to original sources
PubMed2004

Association of phytoplasmas and viruses with malformed clovers.

Plants of Trifolium spp. exhibiting two different kinds of symptoms--phyllody associated with yellowing/reddening, and dwarf growth habit without floral abnormalities--were observed in several areas of the Czechia. Nested polymerase chain reaction (PCR) with phytoplasma specific primers, and restriction fragment length polymorphism (RFLP) analyses of 16SrDNA revealed that phyllody of T. repens was associated with phytoplasmas belonging to the 16SrI-C subgroup. Similar symptoms in T. hybridum and T. pratense plants revealed the presence of phytoplasmas belonging to two subgroups: 16SrI-C and 16SrIII-B. Dwarf disease of cultivated T. pratense plants was associated with more than one agent: 11 of 20 plants examined by PCR/RFLP analysis revealed the presence of phytoplasmas belonging to four distinct subgroups: 16SrI-B, 16SrI-C, 16SrIII-B and 16SrX-A. Moreover, two kinds of bacilliform virions were observed in ultrathin sections of 15 T. pratense plants. Particles occurred mostly in the parenchymatous cells of vascular bundles and were located in the cytoplasm as aggregates within an extended network of membranous cisternae. Phytoplasmas and rhabdoviruses occurred singly, and both together or in co-presence with filamentous virus-like particles.

Czech Republic↗
PubMed2002

[The ACE inhibitor, captopril, in the light of new clinical studies].

Captopril, the classic inhibitor of the angiotensin converting enzyme, was employed in several large clinical studies in recent years. The effect of captopril was compared either with placebo, or captopril was selected as the reference ACE inhibitor for comparison with another therapy. In the classic study SAVE, captopril administered to patients after myocardial infarction with a dysfunction of the left chamber reduced mortality by 19%. Though in the study ELITE the AT1 blocker losartan was more effective to reduce mortality in patients with chronic heart failure than captopril, the larger and mortality-oriented study ELITE II did not demonstrate a difference in mortality reduction between captopril and losartan. ACE inhibitors thus remain drugs of choice in chronic heart failure. AT1 blockers are to be used in the cases when ACE inhibitors are not tolerated. The study CAPPP has demonstrated that captopril in hypertonic patients not only effectively decreases blood pressure but exerts a similar effect on mortality reduction as the classic treatment with a diuretic and a betablocker, the most effective being captopril in diabetic patients. Administration of captopril in hypertonic patients with diabetes mellitus in the study UKPDS had an effect on mortality reduction as well as micro- and macrovascular complications of diabetes similar to that of atenolol. The ongoing study VALIANT compares the AT1 blocker valsartan or a combination of valsartan and captopril with captopril alone on patients at risk after myocardial infarction. Also at the beginning of the 21st century captopril maintains a stable position in the treatment of the cardiovascular system.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2002

[The significance of aldosterone in chronic heart failure: the RALES study].

Reduction of excessive neurohumoral activation in chronic heart failure (CHF) improves the prognoses. In addition to reduction of angiotensin production or angiotensin II action and the influence of the sympathoadrenal system also blocking of aldosterone effects becomes part of the therapeutic procedure in patients with CHF. Excessive systemic and probably also local aldosterone production promotes undesirable fluid retention, hypokalaemia and hypomagnesaemia, induction of hypertrophy and fibrosis of the heart muscle and blood vessels and the development of endothelial dysfunction, peripheral vasoconstriction and depression of the baroreflex. In addition to classical effects also the existence of a rapid, so-called non-genomic effect of aldosterone is assumed. Adding a blocker of aldosterone receptors to ACE inhibition was not recommended due to possibility development of hyperkalaemia. Later it was revealed that ACE inhibitors are unable to block sufficiently the action of aldosterone and that addition of spironolactone in small amounts to ACE inhibition and diuretics does not cause in patients with CHF a major increase of the potassium level. In the RALES study (Randomized Aldacton Evaluation Study) comprising 1663 patients with serious heart failure (NYHA III, IV) addition of 25 mg spironolactone to standard treatment with ACE inhibitor, diuretic and as rule also digoxin reduced the mortality by another 30% as compared with the addition of placebo. Undesirable effects were minimal. As to potential protective mechanisms of spironolactone the greatest importance is ascribed to the reduction of excessive fibrosis of the heart muscle. Spironolactone reduces the level of the circulating N-terminal aminopeptide procollagen type III the high level of which is associated with deterioration of the prognosis.

Aldosterone↗
PubMed2001

[The piggyback technique in venous outflow tract reconstruction in liver transplantation].

Nowadays, the piggyback technique of venous outflow tract reconstruction has been adopted by an increasing number of transplant teams. From January 1996 to August 2000, we used it in 73 of 84 liver transplantations (86.9%) in our institution. We observed one postoperative complication (1.4%) in direct relation to this technique. The main advantages of the piggyback are 1. maintaining of the haemodynamic stability during the anhepatic phase, 2. avoiding of the veno-venous bypass, 3. diminution of blood loss, 4. easier solution of the graft size mismatch problem, 5. shorter manipulation time and 6. easier retransplantation. Disadvantages of the piggyback technique include 1. more technically demanding recipient's hepatectomy, 2. the potential for venous outflow tract obstruction and 3. possible thrombosis in a blind caval pouch. According to our results and experience in the literature, we consider the piggyback technique as a method of choice for venous outflow tract reconstruction in liver transplantation. It can be used in the majority of patients after gaining some experience.

Anastomosis, Surgical↗
PubMed1998

Pharmacokinetics of low doses of methotrexate in patients with psoriasis over the early period of treatment.

OBJECTIVE: The aim of the present study was to investigate the pharmacokinetics and pharmacodynamics of low-dose methotrexate (MTX) in the early phase (3 months) after the start of antipsoriatic therapy. METHODS: Ten male and female psoriatic patients who failed to respond to previous conventional therapy were treated with 15 mg oral MTX once per week. The pharmacokinetics in plasma and the urinary excretion of MTX and 7-hydroxymethotrexate (7-OH MTX) were investigated after doses 1, 5 and 13 (corresponding to phases I, II and III, respectively). On the same occasions, MTX accumulation in erythrocytes obtained before MTX administration was investigated. Pharmacodynamics of MTX were evaluated using the psoriasis area and severity index (PASI) score. RESULTS: There were marked intersubject differences (range of coefficients of variation 34.9-76.3%) in the area under the curve (AUC), peak concentration (Cmax) and clearance (CL) of MTX. Total CL was proportional to renal clearance (CLR) (r2 = 0.735, P < 0.0001) which accounted for 73 (19)% of the former. There was a strong linear relationship (r2 = 0.819, P < 0.0001) between CL of MTX and creatinine clearance. Within 48 h of drug administration, the urinary excretion of MTX was 46-99% of the dose, while that of 7-OH MTX was 1.5-8.6%. In 8 of 10 patients, more than 70% of the MTX dose was recovered. No intraindividual variations of MTX kinetic parameters during treatment were observed. MTX concentrations in erythrocytes reached the steady-state concentration in the range 40.7-170 nmol.l(-1) after 2 months of therapy. Pharmacodynamic measurement versus pharmacokinetics revealed a significant inverse relationship between PASI score and MTX AUC (rs = -0.912, P < 0.002) and between PASI score and erythrocytic MTX (rs = -0.988, P < 0.002). CONCLUSION: The relationship between MTX pharmacokinetics (AUC or erythrocytic MTX) and pharmacodynamics (PASI score) may exist. It is likely that the efficacy of psoriasis therapy with MTX could be improved by adjusting the dose according to plasma concentrations obtained after the first MTX administration.

Adult↗
PubMed1991

[Results of surgical treatment of incomplete forms of atrioventricular septal defects in adults].

At a cardiosurgical department in Brno in 1978-1987 244 patients above 15 years of age were operated for the first ++time on account of inborn heart disease. This number comprised 21 patients (8.6%) with incomplete defects of the atrioventricular septum. Two patients died in the early postoperative period, two patients were lost from the records and 17 patients were subjected to clinical and echocardiographic examination two to 11 years after operation. All patients were in the 1st or 2nd functional class of the NYHA classification, signs of recanalization were found in one patient and progressing mitral regurgitation in two patients. Consistent with data in the literature, the authors consider it important, to check the patients regularly, incl. clinical and echocardiographic examination, after operations of incomplete defects of the atrioventricular septum and to focus special attention of progressing mitral regurgitation.

Adolescent↗
PubMed1990

[Replacement of the aortic valve in patients over 60 years of age].

The authors evaluated a group of operated patients above 60 years of age where the main cardiosurgical operation was a aortic valve replacement. The early mortality in the group comprising 49 patients was 4.1%. (Of 33 patients where the replacement of the aortic valve was an isolated operation none of the patients died. From another 16 patients where also the mitral valve had to be replaced or IHD had to be resolved by revascularization of the heart muscle by aortocoronary bypasses, two patients died.) During a check-up examination one year after operation 92% of the checked patients where in functional group I or II according to NYHA classification (before operation all were in group III or IV). Prostheses of aortic valves do not only considerably prolong the life even in older patients but also improve its quality. Advanced age alone is no contraindication for operation and the surgical risk is not greater than in younger age groups. The authors recommend to implant in advanced age bioprostheses because of the markedly lower risk of serious haemorrhagic complications in the long-term postoperative course.

Aged↗
PubMed1990

[Laboratory findings in patients with melanoma].

Authors studied serum and urine zinc levels in a total of 64 malignant melanomas. From them, in 27 patients the melanogenuria has simultaneously been observed, and the cystinuria in 35, respectively. Mentioned examinations were performed during both the recovery and relapsing periods of tumor manifestations. From the values obtained in both serum and urine, no agreement has been issued with the authors believing that the decrease in serum zinc levels and their increase in urine may be prognostically unfavorable. Similar controverting results were obtained in monitoring melanogenuria as well. In contrast, higher pathological cystinuric values resulted in 50% of tumor relapses. The authors preclude this will be the direction for further observation on by far larger group of patients.

Cystinuria↗
PubMed1987

The mechanism of action of molybdenum and tungsten upon collagen structures in vivo.

The effect of in vivo administration of molybdenum (as sodium molybdate) and tungsten (as sodium tungstate) was investigated in the skin of laboratory rats. It was proved that the amount of both bound molybdenum and tungsten in collagen is relatively small being 0.05 and 0.06 moles per mole respectively. Besides the fraction of firmly bound molybdenum and tungsten a much higher extractable pool of both these metals was found. It was also demonstrated that in vivo shadowing of collagen is caused by the fraction of loosely bound metals. On the other hand pronounced changes were shown in the mechanical properties of connective tissue after molybdate and tungstate administration. Surprisingly, the change in mechanical properties indicated a lower level of cross-linking after the administration of the investigated metals. It is therefore concluded that bitopical binding of molybdenum and tungsten in the collagen structure is unlikely. It also appears that the biological effect of these metals is due to the competition with copper and the interference with the physiological cross-linking reactions based on the partial blockade of lysyloxidase.

Animals↗