Cell Differentiation and Aging Lead To Up-Regulation of FTO, While the ALKBH5 Protein Level Was Stable During Aging but Up-Regulated During in vitro-Induced Cardiomyogenesis.

FTO and ALKBH5 proteins are essential erasers of N6-adenosine methylation in RNA. We studied how levels of FTO and ALKBH5 proteins changed during mouse embryonic development, aging, cardiomyogenesis, and neuroectodermal differentiation. We observed that aging in male and female mice was associated with FTO up-regulation in mouse hearts, brains, lungs, and kidneys, while the ALKBH5 level remained stable. FTO and ALKBH5 proteins were up-regulated during experimentally induced cardiomyogenesis, but the level of ALKBH5 protein was not changed when neuroectodermal differentiation was induced. HDAC1 depletion in mouse ES cells caused FTO down-regulation. In these cells, mRNA, carrying information from genes that regulate histone signature, RNA processing, and cell differentiation, was characterized by a reduced level of N6-adenosine methylation in specific gene loci, primarily regulating cell differentiation into neuroectoderm. Together, when we compared both RNA demethylating proteins, the FTO protein level undergoes the most significant changes during cell differentiation and aging. Thus, we conclude that during aging and neuronal differentiation, m6A RNA demethylation is likely regulated by the FTO protein but not via the function of ALKBH5.

Effect of immunosuppressive therapy in inflammatory cardiomyopathy: data from The Czech Inflammatory Cardiomyopathy Immunosuppressive Trial.

INTRODUCTION: The indications for specific treatment in the cases of inflammatory cardiomyopathy are based on limited data from several small clinical trials. AIM: A comparison of the effect of two dose regimens of combined immunosuppressive therapy by adding them to conventional heart failure therapy and comparing them with conventional heart failure therapy alone in patients with inflammatory cardiomyopathy. METHODS AND STUDY POPULATION: We enrolled 20 patients; mean age 46.10±7.33 years, duration of symptoms <6 months, LVEF ≤40 %, NYHA class II-IV, with biopsy­proven myocarditis. Patients were randomly separated into groups treated with immunosuppressive therapy in addition to conventional heart failure therapy or to a group treated with conventional heart failure therapy alone. Clinical and echocardiographic parameters were evaluated. RESULTS: The baseline values of LVEF in the group of immunosuppressive therapy (LVEF 22.3±4.7 %) were similar to those in the group treated with conventional heart failure therapy (LVEF 21.7±4.7 %; p=0.757). After twelve months there was no statistically significant difference in LVEF between the two studied groups (LVEF 33.7±9.5 % for the immunosuppressive therapy group and 41.3±13.0 % for the conventional therapy group; p=0.175). CONCLUSION: In our study population, we proved no positive effect of combined immunosuppressive therapy on the left ventricular function over 12 months. The main limitation of the study is the small number of enrolled patients (Tab. 4, Fig. 1, Ref. 35).

Metformin therapy and risk of cancer in patients after heart transplantation.

BACKGROUND: Diabetes mellitus (DM) and malignancy are recognized among the most common complications increasing mortality in patients after heart transplantation (HTx). Clinical trials have shown a higher risk for different types of tumours in diabetic patients. This risk is potentiated by immunosuppressive therapy in transplant patients. Biguanide metformin has been shown to exhibit anti-tumour activity and we tried to find out whether this effect is valid for heart transplant patients. METHODS: We retrospectively analysed a group of 497 patients, who undergone HTx in our centre between 1998 and 2019. The primary outcome was any malignancy during the 15-year follow-up period and patient's survival. RESULTS: Out of the 497 patients enrolled in the study, 279 (56 %) had diabetes and 52 (19 %) were treated with metformin. Fifteen-year survival in treated patients without malignancy was 93 %, the remainder for the DM patients was 56 %, with survival in non-DM patients being 74 %. Untreated diabetic patients had 4.7 times higher chance of malignancy than those on metformin (p = 0.01). Fifteen-year survival in metformin treated patients was 53 %, in other DM patients 44 %, and in non-DM patients 51 %. CONCLUSION: Our study showed a significantly lower incidence of malignancies in metformin-treated patients and slightly better overall survival (Tab. 2, Fig. 3, Ref. 19) Keywords: biguanide, heart graft, malignancy, diabetes mellitus, survival.

Autonomic cardiac regulation, blood pressure and cardiorespiratory fitness responses to different training doses over a 12 week group program in the elderly.

AIM: The study assessed the effects of different weekly training frequencies performed over a 12 week exercise programme (strength, endurance, balance) on autonomic cardiac activity, blood pressure and cardiorespiratory fitness (CRF) in elderly individuals. METHODS: Fifty-eight individuals participated in the study: 2TG (N=24, 71.1±6.4 yrs; 19 females, 5 males) performing two, 60min sessions/week; and 3TG (N=34, 72.3±7.9 yrs; 25 females, 9 males) performing three, 60min sessions/week. Time domain and spectral analysis of heart rate variability (HRV) quantified autonomic cardiac regulation. RESULTS: Natural logarithm (Ln) transformation was applied to all HRV parameters. There were significant reductions in total power (Ln TP) (p=0.006), low frequency (Ln LF) (p=0.013), high frequency (Ln HF) (p=0.013) and root mean square of successive differences (Ln rMSSD) (p=0.014) post training in 3TG after intervention. Diastolic BP (DBP) decreased significantly in both groups (2TG: P<0.001; 3TG: P<0.001). Both groups showed significant improvements in six-minute walk distance (2TG: P=0.003, 3TG: P=0.001). However, there were significant HRV differences between 2TG and 3TG for Ln TP (P=0.018), Ln LF (P=0.049), Ln HF (P=0.039) and Ln rMSSD (P=0.049). CONCLUSIONS: A combined exercise programme resulted in improved DBP and CRF irrespective of training two or three 60min sessions/week. However, training three, sessions/week induced negative health-related changes in autonomic cardiac activity through reducing HRV parasympathetic function, while HRV was maintained in the group training twice a week.

Conservative versus invasive treatment in hypertrophic obstructive cardiomyopathy: an echocardiography study.

AIM AND METHODS: The aim of our study was to compare the development of echocardiographic parameters and functional status of patients with hypertrophic obstructive cardiomyopathy (HOCM) treated conservatively (n = 41) or by alcohol septal ablation (ASA; n = 39). RESULTS: Left ventricular outflow tract gradient (LVOTG) decreased in the first year by 53.7±36.4 mmHg in ASA group versus 5.5±47.1 mmHg in conservatively treated group (p<0.001), in the third year by 53.1±41.4 mmHg versus 23.9±42.7 mmHg (p = NS) and in the fifth year, the reduction of LVOTG was 52.1±44.5 mmHg in ASA group and 3.0±63.2 mmHg in conservatively treated group (p<0.05).Change in NYHA class in the first year was -1.1±0.4 versus 0.1±0.5, in the third year -1.0±0.6 versus 0.1±0.4 and in the fifth year -0.8±0.5 versus 0.1±0.4 (all p<0.001). CONCLUSION: Our results showed for the first time that decline of LVOTG after ASA creates a favorable left ventricle remodeling and leads to significant improvement of functional status of HOCM patients in comparison with conservative treatment (Tab. 3, Fig. 2, Ref. 42).

Structural basis of polycomb bodies.

The spatial organization of the cell nucleus into separated domains with a specific macromolecular composition seems to be the fundamental principle that regulates its functioning. Because of the importance of regulation at the nuclear level, the cell nucleus and its domains have been intensively studied. This review is focused on the nuclear domain termed the Polycomb (PcG) body. We summarize and discuss data reported in the literature on different components of the PcG body that could form its structural basis. First, we describe the protein nature of the PcG body and the gene silencing factory model. Second, we review the target genes of Polycomb-mediated silencing and discuss their essentiality for the structural nature of the PcG body. In this respect, two different schematic models are presented. Third, we mention new data on the importance of RNAs, insulator elements and insulator proteins for the structure of PcG bodies. With this review, we hope to illustrate the importance of understanding the nature of the PcG subcompartment. The structural basis of a subcompartment directly reflects its status in the cell nucleus and the mechanism of its function.

Change in performance in response to training load adjustment based on autonomic activity.

The primary aim of this study was to assess performance (Perf) changes in response to a new training strategy. Specifically, based on spectral analysis of heart rate variability (SA HRV) to determine autonomic nervous system (ANS) activity, training doses were adjusted to maintain vagal activity at a high and relatively stable level during training preparation. Trained athletes (5 male and 5 female) aged 23.2±4.2 years voluntarily participated in the study. ANS activity was assessed during an orthoclinostatic test, and was represented by calculating HRV variables and a total score index. Over 17 weeks, improvement (1.4-8.5%) and deterioration (0.1-8.8%) in Perf were detected in 7 and 3 athletes, respectively. A relationship (rs=0.684; P<0.05) between the change in Perf (ΔPerf) and supine PHF during season was found. Supine HRV indices (PHF, PT, and MSSD) for the last 3 weeks of the HRV-adjusting period correlated (rs=0.636; 0.648; 0.648, P<0.05) with ΔPerf. Based on the results, a high and relative stable vagal activity during preparation may indicate a readiness to train or appropriate recovery that positively affects Perf. In conclusion, daily quantification of ANS activity by SA HRV seems to be a promising tool for the enhancement of Perf.

Erlotinib in the treatment of advanced squamous cell NSCLC.

Erlotinib is an epidermal growth factor receptor tyrosine-kinase inhibitor. Clinical trials have shown its efficacy in advanced non-small cell lung cancer (NSCLC). We conducted a large retrospective study based on clinical experience aiming to prove erlotinib's efficacy and safety in patients with advanced-stage squamous cell NSCLC. Totally 375 patients with advanced-stage (IIIB, IV) squamous cell NSCLC were treated with erlotinib. Erlotinib was continued until disease progression or intolerable toxicity. 1 (0.3%) complete response (CR), 28 (7.5%) partial responses (PR) and 198 (52.8%) stable diseases (SD) were achieved. Overall response rate (ORR) and disease control rate (DCR) were 7.8% and 60.5%, respectively. Median progression-free survival (PFS) was 3.0 months and median overall survival (OS) was 7.6 months. PFS of patients with CR/PR, SD and PD were 7.6, 3.9 and 1.0 months, respectively (P<0.001). OS of patients with CR/PR, SD and PD were 13.3, 10.9 and 3.8 months, respectively (P<0.001).The most common adverse effects were rash and diarrhoea. In conclusion ertlotinib is effective and well-tolerated in patients with advanced-stage squamous cell NSCLC.

[Heart transplantation and the subsequent treatment of AL amyloidosis]. / Transplantace srdce a následná lécba AL-amyloidózy.

UNLABELLED: Severe damage to the heart caused by AL amyloid deposits is a contraindication of high-dose chemotherapy with autologous haematopoietic stem cell transplantation. Severe heart damage caused by AL amyloid results in frequent life-threatening complications, even during the course of the classical chemotherapy treatment and it often makes keeping to the treatment schedule impossible. Scheduling heart transplantation before the treatment of AL amyloidosis will significantly improve the patients overall condition and enable them to undergo the intensive AL amyloidosis treatment with the hope that a long-term complete remission may be achieved. CASE DESCRIPTIONS: Transplantations of heart damaged by AL amyloid deposits were conducted in three patients; two men, age 48 and 54, and one woman, age 63. In the interval of 3-6 months from the heart transplantation before the scheduled AL amyloidosis treatment was initiated, an examination of bone marrow, the concentration of monoclonal immunoglobulin and free light chains was carried out. Both men had more than 10% of plasma cells in the bone marrow after the heart transplantation and the concentrations of the λ free light chains were pathologically increased. During the first-line therapy, autologous haematopoietic stem cells were harvested from peripheral blood after mobilizaton with granulocyte growth factor (filgrastim) at the dose of 5 µg/kg twice a day. During the administration of filgrastim until the end of the haematopoietic stem cell harvest, the combined immunosuppressive treatment was reduced and a corticosteroid dose was compensatory increased. The prophylactic antiviral drug valganciclovir was discontinued during the haematopoietic stem cell harvest. High-dose chemotherapy (melphalan 100 mg/m2) with autologous haematopoietic stem cell transplantation followed. In the interval from administering melphalan until the rise in neutrophil count over 2 x 109/l, antiviral prophylaxis was discontinued again, the immunosuppressive drug doses were reduced and corticoid doses were slightly increased. High-dose chemotherapy with melphalan at the of 100 mg/m2 was tolerated without major complications and without mucositis; however, in neither of the male patients did it lead to a complete haematological remission. Consequently, the second-line therapy followed using bortezomib combined with dexamethasone and also with cyclophosphamide or doxorubicin. One of these two patients reached a complete haematological remission after the bortezomib therapy; the values of free light chains were normal, immunofixation was negative, and clonal plasma cells were absent in the bone marrow. In the case of the other patient, the bortezomib therapy only induced partial remission. In this case, the third-line therapy followed, applying a combination of lenalidomide, dexamethasone and cyclophosphamide. This therapy significantly reduced the values of free light chains; however, their ratio remained pathological. To conclude, the latter response can be described as a very good partial remission. Both men currently show no signs of disease activity and are in a good clinical condition 28 and 30 months after the heart transplantation. The third heart transplantation, due to severe heart damage by AL amyloid deposits, was conducted in a woman aged 63. An examination of this woman three months after the heart transplantation showed that the original pathological values of free light chains became normal. The woman had approx. 8% of clonal plasma cells before the heart transplantation. Three months after the heart transplantation the bone marrow contained only 3% of polyclonal plasma cells. In this case, the immunosuppressive treatment with corticosteroids after the heart transplantation probably induced a complete haematologic remission. The woman is in a complete AL amyloidosis remission seven months after the heart transplantation. CONCLUSION: It was beneficial to perform the heart transplantation first and to initiate the AL amyloidosis treatment no sooner than three months after the heart transplantation in patients with severe heart damage caused by AL amyloid deposits. If the patients are in a good clinical conditions, autologous haematopoietic stem cells can be harvested after the heart transplantation and high-dose chemotherapy can be offered to the patients. If this intensive treatment does not induce remission, it is necessary to apply additional alternative treatments.

Second line treatment in advanced non-small cell lung cancer (NSCLC): comparison of efficacy of erlotinib and chemotherapy.

Molecular targeted therapy based on tyrosine kinase inhibitors, directed at the epidermal growth factor receptor (EGFR) is one of novel options for management of NSCLC. Erlotinib is EGFR tyrosine kinase inhibitor used for treatment of the advanced NSCLC. This presented study is focused on comparison of erlotinib and chemotherapy efficacy in the second line treatment of the advanced NSCLC. DCR and PFS became the primary endpoints.Total number of patients was 290. A group treated with chemotherapy in the second line consisted of 150 patients and a group treated with erlotinib in the second line consisted of 140 patients. Comparison of DCR was performed using Fisher's exact test, visualization of PFS was performed using Kaplan-Meier survival curves and differences were tested using the log-rank test. Genetic testing was performed using PCR direct sequencing. In the group treated with chemotherapy 2 CR, 23 PR and 51 SD were achieved vs. 5 CR, 10 PR and 55 SD in the group treated with erlotinib in the second line. DCR in patients treated with chemotherapy was 54.0% vs. 51.3% in patients without EGFR mutation treated with erlotinib (p=0.707); in patients harboring EGFR mutation, treated with erlotinib (n=9) outstanding results were achieved: 4 CR, 2 PR and 3 SD (not tested). Median of PFS in patients treated with chemotherapy was 2.1 months vs. 1.9 months in patients without EGFR mutation (p=0.879) vs. 8.4 months in patients harboring EGFR mutation treated with erlotinib (p=0.017). Results of analysis show that even patients without EGFR mutation are able to benefit from erlotinib treatment in the second line. The efficacy (DCR, PFS) of erlotinib in patients without EGFR mutation was comparable with chemotherapy. The treatment efficacy in a subgroup of patients harbouring EGFR mutation treated with erlotinib was significantly better than in patients without EGFR mutation.

Skin rash as useful marker of erlotinib efficacy in NSCLC and its impact on clinical practice.

Erlotinib is an epidermal growth factor receptor tyrosine kinase inhibitor used in treatment of advanced NSCLC. Patients harboring EGFR or KRAS mutations represent minority of all patients in caucasian population and there is no available predictor for a predominant group of patients harboring the wild-type EGFR and wild-type KRAS genes. Skin rash is the most frequent manifestation of cutaneous toxicity of erlotinib. Rash is associated with a good therapeutic response. We aimed at the evaluation of rash as a predictor of therapeutic effect of erlotinib in patients harboring the wild-type EGFR and KRAS wild-type genes and to assess its possible usage in a clinical practice.Totally 184 patients with advanced stage NSCLC (IIIB, IV) harboring the wild-type EGFR and wild-type KRAS genes were analysed. Comparison of ORR, PFS and OS according to the occurrence of rash was performed. In order to assess the impact of rash in clinical practice it was conducted landmark analysis of the group of patients whose rash was observed during first month of treatment (n=124). Patients in whom progression was observed during the first month of treatment were excluded from the landmark analysis. The comparison of ORR was performed using Fisher's exact test, visualization of survival was performed using Kaplan-Meier survival curves and the differences in survival were tested using the log-rank test. Median PFS in patients who were observed with rash during the treatment was 3.0 vs. 1.2 months in patients with no rash (p<0.001), median of OS in patients who were observed with rash during the treatment was 13.9 vs. 5.8 months in patients with no rash (p<0.001). ORR in patients who were observed with rash during the treatment was 17.4% vs. 3.3% in patients with no rash (p=0.001). Median of PFS after 1 month of treatment in patients who were observed with rash during the first month was 2.9 vs. 1.1 months in patients with no rash (p=0.027). Median of OS after 1 month of treatment in patients who were observed with rash during the first month was 13.8 vs. 9.9 months in patients with no rash (p=0.082). Rash is strongly associated with better survival and ORR in patients harboring wild-type EGFR and wild-type KRAS genes. Occurrence of rash during the first month of treatment is a useful predictor of better effect of erlotinib after one month of treatment. Patients who were not observed with rash during the first month of treatment are in high risk of progression. Optimization of the treatment of these patients can contribute restaging after two months of treatment, assessment of plasma levels of erlotinib and eventually attempt to dose escalation.

[Farmacotherapy of hypertension after heart transplantation]. / Farmakoterapie hypertenze po transplantaci srdce.

Heart transplantation is now used for the treatment of severe heart failure. In a long-term patient follow-up, hypertension has been identified as a complication. Incidence of hypertension in patients treated with cyclosporine and prednisone is between 70-90%. Besides the traditional mechanisms (renin-angiotensin system, fluid volume and peripheral resistance), aetiology of hypertension includes negative effect of cardiac denervation, cyclosporine immunosuppression, administration of corticosteroids and nephropathy. There is no night drop in the blood pressure and heart rate. Treatment aims to maintain cyclosporine level as low as possible and, if feasible, to discontinue steroids during the first year. Hypertension is usually treated with a combination therapy. Our own observations suggest that the majority of post-transplantation patients have a dual therapy. Calcium channel blockers should be the treatment of choice as they also have an effect on graft vasculopathy. Angiotenzin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARB), beta-blockers and diuretics are also recommended. Long-acting products should be preferred.

[EGFR mutations in patients with advanced NSCLC]. / Mutace genu EGFR u pacientu s pokrocilým NSCLC.

BACKGROUND: Molecular targeted therapy based on tyrosine kinase inhibitors, directed at the epidermal growth factor receptor (EGFR) is one of novel options for management of NSCLC. EGFR gene mutations, exon 19 deletions and exon 21 point mutations (L858R) are good predictors of response to EGFR-TKI treatment. The aim of this study was to assess the incidence of EGFR mutations in a large cohort of Europeans with advanced NSCLC and subsequently to evaluate their impact on the effect of EGFR-TKI treatment. PATIENTS AND METHODS: In total, 613 patients with advanced stage NSCLC (IIIB, IV) were genetically tested. The effect of treatment was evaluated in 410 patients treated with EGFR-TKI. Survival was evaluated using Kaplan-Meier method, and statistical comparison was performed using log-rank test. RESULTS: EGFR mutations were detected in 73 (11.9%) patients. Exon 19 deletions were detected in 49 patients, exon 21 point mutations (L858R) were detected in 22 patients, and both mutation types were detected in 2 patients. An increased incidence of EGFR mutations among patients with adenocarcinoma (14.9% vs 7.8%, p = 0.008), women (20.2% vs 7.1%, p < 0.001) and nonsmokers (29.9% vs 7.0%, p < 0.001) was demonstrated. Sixty patients with EGFR mutation and 350 patients with wild-type EGFR were treated with EGFR-TKI. Median PFS in patients harboring EGFR mutation was 7.2 vs 2.0 months in patients harboring wild-type EGFR (p < 0.001), median OS in patients harboring EGFR mutation was 14.5 vs 7.5 months in patients harboring wild-type EGFR (p = 0.019). CONCLUSION: The incidence of EGFR mutations in the studied population, their increased incidence among patients with adenocarcinoma, women and non-smokers correlated with data previously published. Results of survival analysis in patients treated with EGFR-TKI confirmed high potential of EGFR mutations to predict good effect of the EGFR-TKI treatment. Genetic testing in patients with NSCLC should be a standard part of diagnostic procedures

[Validation of the DTP-3 system for noninvasive spinal shape measurement by comparison with X-ray examination]. / Overení presnosti systému DTP-3 urceného pro neinvazivní vysetrení tvaru pátere prostrednictvím rtg vysetrení

PURPOSE OF THE STUDY: Repeated measurements of the spine are absolutely necessary in children and adolescents affected by spinal deformities especially during their growing-up periods. To avoid risks of tissue damage from x-ray exposure, several methods for non-invasive measurement of the spinal curvature have been developed. One of them is the DTP-3 position system allowing for a three-dimensional measurement of anatomical landmarks (spinous processes) and the calculation of curvature angles in both the frontal and sagittal planes. We were interested to know whether the DTP-3 was precise enough to determine the true spinal curvature. MATERIAL AND METHODS: To determine the precision of the DTP-3 system, we constructed a model of the spine. The model was then repeatedly investigated by both the noninvasive and x-ray methods. The distortion of x-ray images caused by the central projection mechanism was considered and included in the calculation. In addition, a group of patients with scoliosis up to 40° was evaluated by both the DTP-3 system and x-ray (the latter according to Cobb's method). RESULTS: Differences in spatial coordinates between DTP-3 and x-ray examinations reached 20.9 mm in the frontal plane and 67.3 mm in the sagittal plane without distortion correction of x-ray images. The differences decreased below 1.5 mm after image distortion correction in each plane. Distortion correction had not the same effect for angle parameters as for coordinates. Differences between the DTP-3 angle parameters and Cobb's x-ray angles were below 4.7°, both without correction and after correction. The difference between DTP-3 angle parameters and Cobb's x-ray angles was -1.8° ± 3.0° (mean ± standard deviation) when measurement was performed on the patients with scoliosis. DISCUSSION: The goal of any clinical examination is to obtain data applicable to decision-making analysis. In the case of scoliosis it is necessary to report results in terms of Cobb's angle, which is the problem for all surface-dependent methods, especially in patients with double curves. A solution may be to define the maximal difference between noninvasive and x-ray methods that could be acceptable for good clinical practice. CONCLUSIONS: In this study we report good concordance between noninvasive and x-ray examinations of a modeled spinal deformity in terms of both angle and linear measurements. The same results were obtained for angle measurements in a group of patients with scoliosis up to 40°. Based on this study and our previous data we believe that the DTP-3 system can be introduced into clinical practice.

Extraordinary response to erlotinib therapy in a patient with lung adenocarcinoma exhibiting KRAS mutation and EGFR amplification.

Case reports on the co-incidence of Kirsten rat sarcoma (KRAS) mutation and epidermal growth factor receptor (EGFR) amplification in patients with NSCLC are very rare. This combination is usually considered a negative prognostic factor, despite EGFR amplification alone having positive predictive value. The whole course of treatment of a patient with both EGFR amplification and KRAS mutation present is decribed. The patient in question was a smoker for whom both first- and second-line chemotherapy had been unsuccessful. In stage IV disease biological therapy was administered and proved highly beneficial. Today, 38 months since commencing the treatment, the patient still has no signs of progression and the therapy is still in progress.

Passive immunisation of post-weaned piglets using hyperimmune serum against experimental Haemophilus parasuis infection.

The protective role of hyperimmune serum in the prevention of Haemophilus parasuis infections in post-weaned piglets was assessed by experimental challenge. The hyperimmune serum was obtained from a pig vaccinated with a commercial vaccine against Glässer's disease. Thirty-eight weaned piglets were divided into four groups: three groups were immunised intramuscularly with 10 ml of hyperimmune serum and one group consisted of unimmunised control animals. All piglets were subsequently infected intraperitoneally with H. parasuis serotype 5 at different times after immunisation. The use of hyperimmune serum provided the piglets with partial protection against experimental infection. The levels of protection indirectly depend on time between serum inoculation and challenge infection. The best protection of piglets against experimental infection was obtained in the group immunised 1 week before inoculation; the same group in which the highest levels of antibodies were detected at the time of challenge.

High sensitivity biosensor measurement based on synchronous detection.

The principle of synchronous detection (SD) has been applied to biosensor measurement. SD principle achieves significant increases in the signal to noise ratio, limit of detection and overall measurement robustness. Application of SD in biosensor measurement improves the analysis of the response and avoids the influence of interference/noise produced by stirring, electromagnetic effects and influence of parasitic currents. SD also enables the decomposition of signal to stimulation response and phenomena with long time of response. Second-order phenomena are identifiable in the signal. Linear statistical model was used to develop software for identification of the stimulation signal in the output current. SD was applied to the response signal of a Photosystem II complex (PSII) biosensor. PSII response to light stimulation follows first order kinetics. The inhibition kinetics of PSII has been studied. Kinetic constants of herbicide binding to PSII depend linearly on herbicide concentration and enable measurement of its concentration at low concentrations (linear range for diuron is 10⁻6 to 10⁻4 mM).

Vagal threshold determination. Effect of age and gender.

Progressive increases in exercise intensity cause significant decreases in vagal activity (VA) until a critical point called the vagal threshold (TVA) is reached. This is where further increases in exercise intensity cause negligible change in VA. This study was designed to develop the algorithm for the TVA determination and to assess the effects of age and gender on its level. The sample consisted of 40 subjects who were divided according to age and gender into 4 groups with 10 subjects each: G1-Men age 25-31, G2-Men age 40-57, G3-Women age 24-28, and G4-Women age 43-56. The vagal responses were assessed by spectral analysis of the heart rate variability method while walking on a treadmill in a steady-state at intensities of 20-70% of the maximal heart rate reserve (MHRR). The mean intensity of 45% MHRR was suggested as the TVA level which is related neither to age nor gender. Heart rate related to TVA (TVA-HR) was affected by gender. High frequency power at TVA was influenced by age. The TVA-HR was considered to be a promising tool for the prescription of a safe level of physical activity for subjects with higher risks of health complications involving elevated sympathoadrenal activity during exercise.