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Biomedical subjects

Z Novák

Publications and source records attributed to Z Novák.

At least 19 recordsLinked to original sources
PubMed2006

New multiple somatic mutations in the RET proto-oncogene associated with a sporadic medullary thyroid carcinoma.

Medullary thyroid carcinoma (MTC) occurs mostly as a sporadic tumor or in connection with inherited cancer syndromes-multiple endocrine neoplasia (MEN) types 2A and 2B and familial MTC. Germline mutations in the RET proto-oncogene are found in most of the familial cases. Somatic mutations in the RET proto-oncogene are detected in 23%-69% of patients with sporadic MTC. The most frequent somatic mutation is Met918Thr in exon 16 and only a small percentage of mutations in other RET exons have been observed. In a very few cases double mutations were found. Genetic screening for somatic mutations in RET exons 10, 11, 13, 14, 15, and 16 in Czech patients with sporadic MTC was carried out by DNA sequencing. This study presents a new triplesomatic mutation Gly911Asp, Met918Thr, and Glu921Lys in exon 16 of the RET proto-oncogene detected in an 18-year-old Czech male patient. In the second case, a new double-somatic mutation Val591Ile in exon 10 with a concomitant somatic mutation Met918Thr in exon 16 was found in a 77-year-old Czech female patient. These both newly described somatic multiple mutations were revealed in a hemizygous status, the loss of heterozygosity in tumor tissues in comparison with germline DNA was confirmed.

Adolescent↗
PubMed2006

[The volumes of the thyroid gland in adults aged 18-65 years in the Czech Republic--determination of the norms].

OBJECTIVE: In the areas with moderate iodine deficit the sonographic examination of thyroid gland is a precious method of precise determination of its volume. The objective of the work was the sonographic examination of males and females aged 18-65 years and to determine the norms of the volumes of thyroid gland. METHODS AND RESULTS: In total, by random sampling, there were sonographically examined 3 416 adults in 11 areas of the Czech Republic; there was chosen a set of 971 females and 681 males whose iodinuria level in first morning urine sample was equal or higher than 100 microg/l. This set was divided according to sex and into the age categories in 5-year interval. The measurement of 3 dimensions of the thyroid gland was determined by Medison-Kretz SA 600 sonographic device with the use of 7.5 MHz linear probe for the depth and width measurement and 3.5 MHz probe was used for the lengths measurement. The volume was determined for each lobe individually using Brunn's formula: V (ml) = 0.479 x length x depth x width. Our results imply the age-related increase of the volume of thyroid gland at both sexes (F-ratio = 1.99, p < 0.0001). At men and women the volume of thyroid gland fluently increases to the 30th year equally, from 30 years to 55 years it increases more rapidly in men while in women there is observed a moderate plateau. Further increase of the volume of thyroid gland is equally fluent from the age of 55 years. CONCLUSION: We managed to determine first own norms of the volumes of thyroid gland for men and women aged 18-65 years in the Czech Republic in five-year age categories. In terms of practical use we recommend 90th percentile as a limit for the evaluation of upper limit of thyroid gland and the 10th percentile for the evaluation of lower limit of the volume of thyroid gland.

Adolescent↗
PubMed2006

[Meningiomas with skull bone involvement].

One of factors responsible for meningioma recurrencies is tumorous involvement of calvarial and basal bone structures. Primary intraosseous meningiomas should be distinguished from secondary involvement in prevailing intracranial tumor and hyperostotic reactive changes. The paper is based on prospective study of 167 patient operated on for intracranial meningioma. Based on clinical investigation, radiological and intraoperative data bone invasion was suspected in 20 patients and histologically confirmed in 17. In 14 patients bone involvement was secondary, meningothelial hamartoma was described in one patient and in 2 patient primary intraosseous meningioma was found. Prevalence of tumors to periorbital area and bone sutures is confirmed. Neuronavigation is used to optimise tumor resection and limit the risk for neurovascular structures. Results were good in 87.5% of patients and poor in 12.5% of patients (extent of tumor and general condition). Discussion provides analysis of intraosseous meningiomas formation, pathological classification (Lang), causes of bone invasion and surgical possibilities. It is necessary to undeline the problems of intraosseous meningiomas both from the aspects of diagnosis and subsequent treatment.

Adult↗
PubMed2006

[Is decreased thyroid echogenity a good indicator of thyroid autoimmune disorder?].

INTRODUCTION: Thyroid gland with mildly decreased or significantly decreased echogenity is indicating possible autoimmune disorder even before first symptoms, i.e. change in laboratory tests measuring the level of thyroid hormones and antibodies to thyroid antigens occur. TARGET: to consider changes in thyroid gland echogenity suspecting thyroid autoimmune disorder and to determine antibodies to thyroid antigens in the respective type of thyroid echogenity (increased, normal, mildly decreased or significantly decreased) to consider the activity of autoimmune thyropathies related to echogenity and to compare these factors. METHODS: Echogenity of the thyroid gland was examinated in randomly selected population (n = 1 055, 360 male, 695 female) in 11 regions of the Czech republic, all presented with urinary iodine concentration > 100 microg/L of urine. The echogenity was determined in 4-level scale as increased (1), normal (0), mildly decreased (-1) and significantly decreased (-2). Texture of thyroid was evaluated in 2-level scale as homogenous or non-homogenous. For the evaluation of the relation between echogenity type (1 to -2) and TgAb, and between the type of echogenity and TOPAb frequence analysis (logarithm-linear modules) was used, i.e. the complete module was compared with the measured values. RESULTS: The selected adults (695 female, 360 male) with urinary iodine concentration > 100 microg/L of urine presented with increased echogenity in 2 females (0.28%) and 1 male (0.28%), normal echogenity in 281 females (40.42%) and 206 males (57.22%), mildly decreased echogenity in 288 females (41.43%) and 128 males (35.56%) and significantly decreased echogenity in 124 females (17.84%) and 25 males (6.95%). The biggest group, both in males and in females, presented with normal and mildly decreased echogenity. Homogenous thyroid gland structure was found in 223 females (32.08%) and 220 males (61.11%). Non-homogenous texture was found in 472 females (67.92 %) and 140 males (38.89%). Frequence analysis both in males and in females was focused on: 1. relation between the echogenity (ECHO) and TgAb: in females with positive TgAb (14.23%), significant relation to ECHO can be seen (p < 0,0001), in contradiction to males; 2. relation between the echogenity (ECHO) and TPOAb: this relation is very significant both in males and in females (p < 0.0001); 3. mutual relation between TgAb and TPOAb: both in males and in females very significant (p < 0.0001); positive relation between antibodies can be seen. Positive presence of antibodies can be found less frequent, negative presence of both antibodies is more frequent; 4. relation between the echogenity, TgAb and TPOAb: no statistic significance was found. CONCLUSION: Homogenous thyroid gland structure was mainly found in males and, on the contrary, non-homogenous structure in females. In 52.7% of adults with significantly decreased echogenity, autoimmune disorder was confirmed in laboratory tests at the same time. With echogenity increasing, TgAb and TPOAb decreased, vice versa. Sonography, evaluating decreased echogenity, can be an early indicator of serious thyropathies before function parameters and clinical symptoms appear. Detected risky adults with sonographic signs of autoimmune disorder have to be monitored and respective treatment considered and started at the very first occurence of positive antibodies even if the function is still normal.

Adult↗
PubMed2005

Regulation of proteolytic activity induced by inflammatory stimuli in lung epithelial cells.

A large number of chronic lung diseases such as asthma bronchiale are associated with alveolar and/or bronchial inflammation accompanied by a damage of the alveolocapillary barrier. In this process proteolytic mechanisms may play a crucial role. The aim of the present study was to assess the role of TNF-alpha on the proteolytic activity of pulmonary epithelial cells and to find possible intracellular signaling pathways which may mediate the effect of TNF-alpha. For our studies we have used the A549 human lung epithelial cell line. Plasminogen activator and metalloproteinase activity was measured using zymography. TNF-alpha induced a time and concentration dependent activation of the urokinase type plasminogen activator (u-PA) and tissue type plasminogen activator (t-PA) activity in A549 cells. This effect could be blocked completely by dexamethasone and was reduced significantly by the Rho-kinase inhibitor Y27632. Similarly, an increased activity in the culture medium of the 72 kDa MMP-2 in response to TNF-alpha could be observed as well. This could be reduced by dexamethasone and Y27632. Our results show that TNF-alpha is at least partly responsible for an increased proteolytic activity and beside corticosteroids Rho-kinase may constitute a potential target for future therapeutical approaches.

Cell Movement↗
PubMed2003

Complex karyotypes in childhood acute lymphoblastic leukemia: cytogenetic and molecular cytogenetic study of 21 cases.

Cytogenetic and molecular cytogenetic analysis of 79 childhood acute lymphoblastic leukemias (ALL) revealed chromosomal abnormalities in 76 (96%). Complex karyotypes (a finding of three and more chromosomal aberrations in a karyotype) were identified in 21 (26.6%) out of 79 patients. In 11 patients, complex karyotypes have included common recurrent chromosomal abnormalities, such as translocation t(12;21) in seven cases, t(9;22) in two cases, one case with t(2;1;19) and another one with translocation involving 11q23. In 10 patients, miscellaneous abnormalities were detected. Five patients displayed hyperdiploidy (47 approximately 57 chromosomes), three patients complex karyotypes with deletions of 9p, one patient with two new complex translocations t(2;4;12;13) and t(7;11;20), and the last patient with dic(12;21). The evaluation of the frequency of the chromosomal breaks (>5 per chromosome) showed that chromosomes 2, 4, 5, 7, 9, 12, 13, and 21 were most frequently affected. Survival analysis revealed statistically significant unfavorable event-free survival (EFS) (P=0.013) and decreased overall survival in the group with complex karyotypes (n=21) compared with the other cases (n=58). The evaluation of overexpression profile revealed increased occurrence of double CD13/CD33 positivity in patients with common recurrent chromosomal abnormalities (in 70% of cases); no such cases were registered in the other group (P<0.01).

Antigens, CD↗
PubMed2003

Effect of vagal nerve stimulation on patients with bitemporal epilepsy.

Patients with bitemporal epilepsy are characterized by the existence of independent bitemporal seizure onset zones. The aim of this study was to evaluate the effect of chronic vagal nerve stimulation (VNS) on eight patients with bitemporal epilepsy. We demonstrated the gradually increased effect of VNS on the reduction of seizures as compared with baseline seizure frequency in patients with bitemporal epilepsy. The average seizure reduction increased from 4.2% at the 3-month follow-up visit to 18.2, 34.4 and 42.2% at the 6, 12 and 18-month follow-up visits. Similarly, a >or=50% reduction of complex partial seizures was reported at the 3-month follow-up visit in no patients (0%); at the 6-month follow-up visit in one patient (12.5%); at the 12-month follow-up visit in three patients (37.5%); and at the 18-month follow-up visit in five patients (62.5%). These data demonstrate the positive and long-lasting effect of VNS on seizure reduction in patients with intractable bitemporal epilepsy. The main mechanism of this chronic effect is not fully understood.

Adult↗
PubMed2003

[Endoscopic surgery of brain structures outside of the cerebrospinal fluid space].

The technique of endoscopy in present-day neurosurgery has been extended also outside the liquor space of the brain, especially in the treatment of brain bleeding, brain tumors or after brain injuries. The authors describe their experience after operating on 45 patients, where the endoscopic intervention has been successfully applied therapeutically or at least in preparing a final solution by means of microsurgery of radiosurgery. Its has become obvious that, in addition to the programmed navigation of the endoscope to the goal, a more flexible manipulation with endoscope while using present stereotactic devices.

Adult↗
PubMed2001

UVB irradiation-induced apoptosis increased in lymphocytes of Huntington's disease patients.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by CAG repeat expansion in the IT-15 gene coding for huntingtin. The mechanism of neuronal degeneration induced by the mutant huntingtin is not known. Apoptosis may play a role in it. Huntingtin is widely expressed in the cells, so abnormalities can be expected also in non-neural tissue. We examined the susceptibility of lymphocytes from HD patients, asymptomatic carriers and normal individuals to UVB irradiation-induced apoptosis. Lymphocytes from eight HD patients and two asymptomatic carriers showed increased apoptotic cell death compared to controls. Our results suggests that sensitivity of HD cells to induced apoptosis is not restricted to neurons.

Adult↗
PubMed2001

Effect of vagal nerve stimulation on auditory and visual event-related potentials.

Chronic unilateral vagal nerve stimulation (VNS) has been recently introduced into the therapy for intractable epileptic seizures. Its effect on cognitive functions in VNS-treated patients remains controversial. The aim of the present study was to evaluate the possible impact of therapeutic VNS on cognitive functions by means of event-related potentials analysis. Ten patients with medically intractable epilepsy, who had been implanted with VNS devices, participated in the study. Auditory and visual event-related potentials (ERPs) were repeatedly recorded, first just before the implantation of VNS devices, and then again 3-6 months after the device activation. The effect of lower intensity stimulation on the P3 component of ERPs was assessed. No significant differences were found in auditory ERPs; the latencies of P3 as well as N2/P3 peak-to-peak amplitudes were virtually identical. The same was true for mean P3 latencies of visual ERPs. However, higher visual N2/P3 peak-to-peak amplitudes were observed in the responses to targets that followed VNS, with a significant finding at the electrodes investigated. When comparing the effect of VNS on visual N2/P3 amplitude in each electrode separately, the most expressive differences were found in the frontal region. This observation supports the theory of a possible positive effect of low-intensity VNS on the cognitive functions.

Adult↗
PubMed2001

A mannose-binding receptor is expressed on human keratinocytes and mediates killing of Candida albicans.

Human keratinocytes are known to kill Candida albicans in vitro, but the mechanism of killing is not yet understood. Here, we demonstrate that spontaneous, ultraviolet-B-light-induced, alpha-melanocyte-stimulating-hormone-induced, and interleukin-8-induced Candida killing by keratinocytes can be inhibited with mannan and mannosylated bovine serum albumin (Man-BSA). A polyclonal goat serum raised against the human macrophage mannose receptor stained suprabasal keratinocytes, but no staining was observed on keratinocytes with a monoclonal antibody (mAb15) specific for the human macrophage mannose receptor. Mannose-affinity chromatography of keratinocyte extract isolated a 200 kDa protein, and on the Western blot the goat antiserum reacted with a 200 kDa protein. In radioligand binding studies, the binding of 125I-Man-BSA to human keratinocytes was inhibited by mannan in a concentration-dependent manner. Analysis of the binding revealed a single class keratinocyte mannose receptor with a KD of 1.4 x 10(-8) M and a Bmax of 1 x 10(4) binding sites per cell. The binding of 125I-Man- BSA to keratinocytes proved to be time-dependent, acid-precipitable, and Ca2+- and trypsin-sensitive. After trypsinization the receptors underwent a rapid recovery at 37 degrees C. These results demonstrate the presence of mannose receptor on human keratinocytes, and its active involvement in the killing of Candida albicans.

Antibodies, Monoclonal↗
PubMed2001

[A universal stereotactic device for spinal cord surgery].

Technical description of a universal stereotactic system for spinal cord operations is presented after a short overview of the history of spinal cord stereotaxis. When combined with the topometric atlas of the cord, new era of spinal cord stereotaxis can be opened, which is going to expand the amount of knowledge about the physiology of the spinal cord.

Equipment Design↗
PubMed2001

[Advances in the diagnosis of tumours by imaging methods (possibilities of three-dimensional imaging and application to volumetric resections of brain tumours with evaluation in virtual reality and subsequent stereotactically navigated demarcation].

Oncological problems are so varied that it is very difficult to record all advances in different diagnostic branches in a comprehensive manner. In the first part the authors focus attention on an example of the possible use of imaging examination methods in conjunction with different types of three-dimensional imaging used in their hospital. The second part is devoted to volumetric resections of brain tumours with navigated demarcation. In 17 patients the authors used the PC working station equipped with navigation software STEREOPLAN PLUS for planning volumetric resection of different brain tumours in virtual reality. The demarcation proper of the brain tumour size during surgery was implemented by means of a stereotactic apparatus ZAMORANO-DUJOVNY and a pointer in the field of the microscope. The accuracy of navigation of the whole system for demarcation of the tumourous affection was +/- 1 mm. The intervention was supplemented by functional examination by means of surface electrodes during partial awakening of the patient for mapping the functional areas of the cerebral cortex. The result was resection of relatively precise volumes of tumourous tissue with the possibility of maximum preservation in particular of motor but also other functions of the CNS.

Adult↗
PubMed2000

[The hepatic form of Wilson's disease in young patients].

UNLABELLED: Wilson's disease (WD) is a hereditary disorder of the copper metabolism with very varied clinical and biochemical symptoms. Hepatic and neurological forms are the most frequent manifestations of this rare disease. In schoolchildren and adolescents symptoms of liver damage predominate. In a retrospective study 19 patients were evaluated with biochemical signs of hepatopathy manifested before the age of 18 years. The diagnosis of WD was established at the age of 7 to 27 years. One female patient was admitted with fulminant hepatic failure which was treated by acute transplantation of the liver in the Institute of Clinical and Experimental Medicine in Prague. Only 9 of 18 patients with chronic hepatic affection at the time of diagnosis met the Sternlieb diagnostic criteria. These patients had reduced ceruloplasmin levels (0.08-0.18 g/l) and a high copper content in the hepatic dry matter (783 ug/g +/- 323 [SD]). In the remaining 9 patients the ceruloplasmin level was normal, however, in 8 a high copper content of the hepatic dry matter was found (696 ug/g (+)- 352[SD]. The last patient from this group had Kayser-Fleischer's (K-F) ring. It was possible to confirm the high copper content in the hepatic dry matter only after one year's penicillinamine treatment because at the time of the diagnosis poor coagulation did not permit to perform a liver biopsy. There was a statistically significant difference in the copper content of the hepatic dry matter in patients meeting and not meeting Sternlieb's criteria. Statistically significant differences between both groups were found in the plasma copper levels and in the 24-hour urinary copper excretion. Histological examination of the liver under a light microscope revealed findings from minimal changes associated with the presence of glycogen nuclei in hepatocytes to the picture of active chronic hepatitis. In all 19 patients the gene mutation H1069Q was examined and the results were positive in 39.8%. In 3 asymptomatic patients it was present in the homozygous form. CONCLUSION: Early detection of the atypical form of WD remains very difficult. The gold standard is still in all cases assessment of copper in the dry liver tissue. In the near future an important place will be held also by direct DNA analysis although its use is limited not only by the large number of known mutations but also by the financial costs of the method.

Adolescent↗
PubMed2000

[An unusual case of primary hyperparathyroidism in a woman with Gorlin-Goltz syndrome].

Nevoid basal cell carcinoma syndrome (NBCCS) has been known to coincide with different forms of other neoplasias; however, parathyroid adenoma in this syndrome has not previously been described. The authors report a case of such association in a 50-year old white woman. The adenoma was verified before operation by biochemical, isotopic and cytologic methods and later, after the excision of adenoma, histologically.

Adenoma↗
PubMed1999

Differential antileukemic activity of prednisolone and dexamethasone in freshly isolated leukemic cells.

This study was designed to compare the antileukemic activity of prednisolone and dexamethasone in childhood acute lymphoblastic leukemia (ALL) under in vitro conditions. The chemoresistance of leukemic cells was ascertained by means of a MTT assay in 69 ALL children at diagnosis and the concentration killing 50% of leukemic cells (LCS50) was determined. The children were treated using the protocol ALL-BFM 90/95. Statistical correlations were made among prednisolone (PRED) and/or dexamethasone (DEX) LCS50 and absolute number of blast cells (ANB) on day 0/8 and a new parameter named blast cells clearance (BCC, BCC8 [%] = ANB8: ANB0 x 100) on day 8. Despite the previously published results of Ito et al. (J. Clin. Oncol. 14: 2370-2376, 1996) and Kaspers et al. (MPO 27: 114-121, 1996) on a positive correlation of DEX versus PRED LCS50 (p < 0.002), in our study, we identified 30% of children (21/69) with differential in vitro responsiveness to PRED and DEX. 16% of patients (11/69) were highly sensitive to DEX and resistant to PRED, while 14% of them (10/69) were resistant to DEX and highly sensitive to PRED. The major difference found in our and the other studies was in the processing of leukemic cells. These results were confirmed in a model experiment using the CCRF-CEM line, where we showed that sensitivity to PRED and DEX, but not to other anti-cancer drugs critically depends on manipulation with tumor cells (cryopreservation). Correlation of PRED/DEX in vitro sensitivity values with parameters of in vivo patient's response to PRED monotherapy identified significant association of PRED LCS50 with BCC8 (p < 0.02). It indicates strong linkage of in vitro sensitivity to PRED with percentage of blast cells eliminated from patient blood within the first 8 days of PRED monotherapy.

Adolescent↗
PubMed1998

[Treatment of endocrine orbital disease by elimination of the thyroid gland. The effect of unsuccessful elimination, severe pretibial myxedema and persistence of hypothyroidism after removal in long-term results].

The reason why soon after elimination of the thyroid gland protrusion of the bulbi does not recede and adequate regression of soft orbital tissue infiltration does not occur is at first the short time which has elapsed after elimination. The result usually is recorded only later. The long-term cause of minor improvement is the impossibility to combine surgery of the thyroid gland and radioiodine with corticoids, as well as incomplete thyroid elimination and presence of residues and finally pretibial myxoedema associated with a persisting high level of antibodies against the receptor for TSH. Hypothyroidism after the eliminating dose must not be left too long, so far a period of 3-4 weeks seems adequate.

Glucocorticoids↗