Biomedical subjects

J Kucera

Publications and source records attributed to J Kucera.

At least 19 recordsLinked to original sources

PubMed2006

Human urine certified reference material CZ 6010: creatinine and toluene metabolites (hippuric acid and o-cresol) and a benzene metabolite (phenol).

A reference material for the biological monitoring of occupational exposure to toluene, benzene and phenol was prepared. O-cresol and hippuric acid (metabolites of toluene) are used for the biological monitoring of occupational exposure to toluene. Phenol, a metabolite of benzene, is used for the biological monitoring of exposure to benzene, but phenol can of course also be used as an indicator of exposure to phenol as well. The reference material (RM) used for the determination of these metabolites was prepared by freeze-drying pooled urine samples obtained from healthy persons occupationally exposed to toluene and those taking part in an inhalation experiment. Tests for homogeneity and stability were performed by determining urine concentrations of o-cresol, hippuric acid, creatinine and phenol. To investigate the stability of the RM, the urinary concentrations of o-cresol and phenol were monitored for eighteen months using GC and HPLC, while those of hippuric acid and creatinine were followed for five and six years, respectively, using HPLC. Analysis of variance showed that the concentrations did not change. The certified concentration values (and their uncertainties) of the substances in this reference material (phenol concentration c=6.46+/-0.58 mg l(-1); o-cresol concentration c=1.17+/-0.15 mg l(-1); hippuric acid concentration c=1328+/-30 mg l(-1); creatinine concentration c=0.82+/-0.10 g l(-1)) were evaluated via the interactive statistical programme IPECA.

Benzene↗

PubMed2006

ETS transcription factor ER81 is required for the Pacinian corpuscle development.

ER81, a member of the ETS family of transcription factors, is involved in processes of specification of neuronal identity, control of sensory-motor connectivity, and differentiation of muscle spindles. Spindles either degenerate or are abnormal in mutant mice lacking ER81. We examined whether ER81 is required for the development of another class of mechanoreceptors, the Pacinian corpuscle. ER81 was expressed by the inner core cells of the corpuscles, as reflected by expression of the lacZ reporter gene in Er81(+/lacZ) mutants, thereby suggesting a role for ER81 in the corpuscle development. No Pacinian corpuscles or their afferent nerve fibers were present in the crus of Er81 null mice at birth. Legs of mutant embryos examined at E16.5 were also devoid of the corpuscles, but not of their afferents. Thus, Pacinian corpuscles do not form, and their afferents do not survive, in the absence of ER81. A deficiency of dorsal root ganglia neurons expressing calretinin, a marker for neurons subserving Pacinian corpuscles, correlated with the absence of corpuscles and their afferents in Er81 null mice. These observations indicate a requirement for ER81 in the assembly of Pacinian corpuscles and the survival of the sensory neurons that innervate them.

Animals↗

PubMed2006

Neurotrophin-3 ameliorates sensory-motor deficits in Er81-deficient mice.

Two factors, the ETS transcription factor ER81 and skeletal muscle-derived neurotrophin-3 (NT3), are essential for the formation of muscle spindles and the function of spindle afferent-motoneuron synapses in the spinal cord. Spindles either degenerate completely or are abnormal, and spindle afferents fail to project to spinal motoneurons in Er81 null mice; however, the interactions between ER81 and NT3 during the processes of afferent neuron and muscle spindle development are poorly understood. To examine if overexpression of NT3 in muscle rescues spindles and afferent-motoneuron connectivity in the absence of ER81, we generated myoNT3;Er81(-/-) double-mutant mice that selectively overexpress NT3 in muscle in the absence of ER81. Spindle reflex arcs in myoNT3;Er81(-/-) mutants differed greatly from Er81 null mice. Muscle spindle densities were greater and more afferents projected into the ventral spinal cord in myoNT3;Er81(-/-) mice. Spindles of myoNT3;Er81(-/-) muscles responded normally to repetitive muscle taps, and the monosynaptic inputs from Ia afferents to motoneurons, grossly reduced in Er81(-/-) mutants, were restored to wild-type levels in myoNT3;Er81(-/-) mice. Thus, an excess of muscle-derived NT3 reverses deficits in spindle numbers and afferent function induced by the absence of ER81. We conclude that muscle-derived NT3 can modulate spindle density and afferent-motoneuron connectivity independently of ER81.

Animals↗

PubMed2005

Congenital diaphragmatic hernia associated with esophageal atresia, tracheoesophageal fistula, and truncus arteriosus in a premature newborn.

The occurrence of coexisting congenital diaphragmatic hernia (CDH) and esophageal atresia (EA) with distal tracheoesophageal fistula (TEF) is extremely rare and is considered highly lethal. The combination of CDH with EA/TEF and truncus arteriosus communis (TAC) has not been reported in the literature to date. The authors describe a premature neonate with this association.

Esophageal Atresia↗

PubMed2004

Pacinian corpuscle development involves multiple Trk signaling pathways.

The development of crural Pacinian corpuscles was explored in neonatal mutant mice lacking nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3) or neurotrophin-4 (NT4), or their cognate Trk receptors. Deficits of the corpuscles and their afferents were greatest in NT3, less in BDNF, and least in NT4 null mice. Deletion of NGF or p75(NTR) genes had little or no impact. No Pacinian corpuscles were present in NT3;BDNF and NT3;NT4 double or NT3;BDNF;NT4 triple null mice. Deficits were larger in NT3 than TrkC mutants and were comparable to deficits observed in TrkB or TrkA mutants. Afferents of all corpuscles coexpressed TrkA and TrkB receptors, and some afferents coexpressed all three Trk receptors. Our results suggest that multiple neurotrophins, in particular NT3, regulate the density of crural Pacinian corpuscles, most likely by regulating the survival of sensory neurons. In addition, NT3/TrkB and/or NT3/TrkA signaling plays a greater role than NT3/TrkC signaling in afferents to developing Pacinian corpuscles.

Animals↗

PubMed2004

Age-related changes in nigrostriatal dopaminergic function are accentuated in +/- brain-derived neurotrophic factor mice.

The effects of a deletion for the brain derived neurotrophic factor (BDNF) allele (+/- BDNF) upon age-related changes in nigrostriatal dopaminergic (NSDA) function were assessed. Behavioral (beam crossing and spontaneous activity) and neurochemical (potassium-stimulated dopamine release from superfused striatum) measures were compared among Young (4-5 month), Middle (11-13 month) and Aged (19-21 month) +/- BDNF and their wild type littermate control (+/+ BDNF) mice. No statistically significant differences were obtained between +/+ and +/- BDNF mice at the Young age sampling period for any of the behavioral or neurochemical measures. Behavioral and neurochemical responses indices of NSDA function begin to diverge between +/+ and +/- Middle age BDNF mice and maximal differences were observed at the Aged period. For both movement and stereotypy times, scores obtained from +/+ mice were significantly decreased compared with +/- BDNF mice at the Aged period and center time scores of +/+ mice were decreased at both the Middle and Aged periods compared with +/- BDNF mice. Neurochemically, potassium-stimulated DA release of +/+ mice was significantly greater than +/- BDNF mice with maximal differences obtained at the Aged period. These results demonstrate marked differences in age-related changes of NSDA function between +/+ and +/- BDNF mice and suggest that the deletion of one allele for BDNF may make these mice more susceptible to age-related declines in NSDA function.

Aging↗

PubMed2004

[A rare shortening of the first metatarsus of the foot and its treatment with distraction arthrodesis].

Multiple toes may develop on the medial or lateral side of the forefoot or in its middle. This may involve duplication of only the distal phalanx or the whole hallux including the metatarsal. In a duplicated big toe, the phalanx to be maintained, because short muscles of the leg are attached to it, is usually localized medially. A rare case of dysplasia of the first metatarsus, following a resection indicated in childhood for a hallux triples, is described in a 20-year-old girl. In order to remove hallux insufficiency and an overloading of the middle metatarsals, the authors decided to carry out a one-stage prolongation of the first metatarsal, using an autologous tricorticcal graft collected from the pelvis and a dynamic compression plate. No surgical treatment of the middle metatarsals was indicated because a disproportionate, short foot would result. Both the subjective and objective status of the patient at 6 months after the operation showed that the non-standard prolongation procedure was correctly indicated and allowed for physiological loading of the foot and restoration of normal walking.

Adult↗

PubMed2004

[The incidence of serious complications in neonates with birth weight < 1,500 g in the Czech Republic (in the period 2000-2002)].

OBJECTIVE: To analyse the incidence of serious complications in neonates with birth weight lower than 1,500 g in the Czech Republic in the years 2000-2002. DESIGN: A retrospective epidemiological study. METHODS: Frequency analysis of the data from the National Register of Neonates, administrated by the Institute of Health Information and Statistics of the Czech Republic. RESULTS: The incidence of PIVH of level III-IV in neonates with weight of up to 1,500 g in the Czech Republic in the years 2000-2002 was 6.8-10.3%; the incidence of cPVL reached 6.4-7.6%; the incidence of ROP of level III and of a higher level was 6.6-7.9% and the incidence of NEC was between 4.3 and 5.7% of all live births. Among the surviving neonates, the percentages of those who did not have any of the PIVH, ROP, HIE or meningitis diagnoses in the reference period were as follows (according to their birth weights): 500-749g 50-63.8%; 750-999 g 69.7-74.8%; 1,000-1,499 g 86.8-91.4%; 1,500-1,999g 98-98.2%; 2,000-2,499 g 99.4-99.5%; and in the group with weight above 2,500g, the percentage was 99.9%. CONCLUSION: The incidence of serious complications in neonates with birth weight of up to 1,500 g in the Czech Republic in the years 2000-2002 was comparable with the data stated in the literature, except for cPVL, the incidence of which was higher in the Czech Republic. The proportion of neonates, who were released and did not have any of the complications, which pose a risk to normal neurosensory development, does not virtually change for birth weights higher than 1,500 g and reaches 98 and more percent. However, among the surviving neonates with birth weight of up to 750, their proportion is mere 50-64%.

Czech Republic↗

PubMed2004

[The first experience with linezolide in treatment of nosocomial septic condition in premature neonates].

OBJECTIVE: Nosocomial infections caused by the coagulase-negative staphylococci are among the most frequent complications in an intensive care unit for neonates. The authors describe three cases of successful treatment of this complication in which the new antibiotic Linezolide was used. DESIGN: Analysis of three clinical cases. SETTING: Mother and Child Care Institute, Prague. METHODS: Description of cases of nosocomial sepsis in 3 immature neonates where the usual treatment of multiresistant strains of coagulase-negative staphylococci, based on the use of Vankomycin, was not successful. CONCLUSION: Administration of Linezolide proved to be very effective in all of the described cases. In spite of the high effectiveness and relative safety of this preparation, its precise role in the treatment of infection-related complications caused by coagulase-negative staphylococci has not yet been established. For the time being, we recommend administering this preparation only in strictly indicated cases after the usual therapy fails.

Acetamides↗

PubMed2003

Human urine certified reference material CZ 6009: creatinine, styrene metabolites (mandelic acid and phenylglyoxylic acid).

The reference material was prepared by freeze-drying pooled urine samples obtained from healthy persons occupationally exposed to styrene. The concentrations of mandelic acid (MA), phenylglyoxylic acid (PGA), and hippuric acid (HA) in urine were determined by three modes of high-performance liquid chromatography (HPLC). For isochronous stability testing the urinary mandelic acid and phenylglyoxylic acid concentrations were followed over a 24-month period for a preliminary batch by use of HPLC. No changes of the concentration values were found. The creatinine concentration was stable for more than five years. Standard Reference Material NIST 914a Creatinine was used for traceability purposes for creatinine. Pure chemicals MA and PGA were used for traceability purposes. Control material ClinChek-Urine Control (Recipe) was analyzed simultaneously. The mean values of MA and PGA compare well with the means and fall within the control range of control samples. Results from homogeneity, stability, and traceability testing were evaluated using the statistical program ANOVA. The certified values and their uncertainties were evaluated from the results of interlaboratory comparisons, and homogeneity and stability tests. The values are unweighed arithmetical averages of accepted results and their uncertainties are combined uncertainties (coverage factor=1).

Adult↗

PubMed2003

Iodine-129 and caesium-137 in Chernobyl contaminated soil and their chemical fractionation.

Soil samples from areas in Belarus, Russia and Sweden contaminated by the Chernobyl accident were analysed for (129)I by radiochemical neutron activation analysis, as well as for 137Cs by gamma-spectrometry. The atomic ratio of (129)I/137Cs in the upper layer of the examined soil cores ranged from 0.10 to 0.30, with an average of 0.18, and no correlation between (129)I/137Cs ratio and the distance from Chernobyl reactor to sampling location was observed. It seems feasible to use the (129)I/137Cs ratio to reconstruct the deposition pattern of 131I in these areas. The association of (129)I and 137Cs in the Chernobyl soil and Irish Sea sediment was investigated by a sequential extraction method. Similar speciation of (129)I in the Chernobyl soil and Irish Sea sediment was found. Approximately 70% of (129)I is bound to oxides and organic matter, and 10-20% is in the readily available phase, while most of the 137Cs (73%) in Chernobyl soil remains in the extraction residue.

Cesium Radioisotopes↗

PubMed2003

Iodine-129 in thyroid and urine in Ukraine and Denmark.

Human thyroids collected from Gomel in Belarus, sheep thyroid from Jutland and human urine from Zealand in Denmark were analysed for 129I and 127I concentrations. The ratios of 129I/127I in human thyroid in Gomel are 2.65-11.0 x 10(-9) with an average of 7.21 x 10(-9), which is one order of magnitude higher than those from Asia and South America (10(-10)), but significantly lower than those observed in west Europe (10(-8)). A weak negative correlation (P < 0.05) between 129I/127I ratio in human thyroid and the age of the subjects was observed in Gomel. The average ratio of 129I/127I in sheep thyroids from Jutland of Denmark is 1.81 x 10(-7), which is two orders of magnitude higher than those in south hemisphere, and Asia. It is also significantly higher than those observed in other west European countries before 1984 and that in human thyroid in Gomel. The high thyroid 129I level in Jutland is attributed to the release of reprocessing plants in France and UK. The 129I/127I ratios in human urine in Zealand of Denmark are 0.86-2.86 x 10(-8). The possibility of using urine 129I to evaluate the thyroid exposure to 129I is investigated.

Adolescent↗

PubMed2002

Quality control materials for the determination of trace elements in airborne particulate matter.

The development of quality control materials for the determination of selected trace elements in air pollution studies is described. Three types of test samples were prepared for proficiency testing: (1) filters loaded with PM10 fraction of urban air particulate matter (APM) using high-volume air samplers, which were subsequently divided into smaller sections, (2) a bulk sample of APM collected in an automobile tunnel in Prague, and (3) simulated air filters loaded with APM using a wet deposition process. Homogeneity of the test samples was studied using instrumental neutron activation analysis, proton induced X-ray emission and atomic absorption spectrometry, and inductively coupled plasma optical emission spectrometry and mass spectrometry. Sufficiently homogeneous samples were prepared by all three procedures. The simulated air filters appeared to be the most suitable test samples for proficiency testing.

Journal Article↗

PubMed2002

Formation of supernumerary muscle spindles at the expense of Golgi tendon organs in ER81-deficient mice.

ER81, a member of the ETS family of transcription factors, is essential for the formation of connections between sensory and motor neurons in the spinal cord. Mice lacking Er81 genes exhibit reduced monosynaptic sensory-motoneuron connectivity in response to muscle nerve stimulation. Proximal muscle nerve stimulation elicits fewer monosynaptic potentials than stimulation of distal nerves in hindlimbs, a deficit that is paralleled by a paucity of muscle spindles in proximal muscles (Arber et al., 2000). We examined whether a presence of spindles innervated by afferents in distal muscles correlated with the increased preservation of monosynaptic sensory-motor potentials in distal muscle nerves. Not only were spindles and Ia afferents present, but also they were supernumerary in distal muscles such as the soleus, medial gastrocnemius, and extensor hallucis longus. Concomitantly, a deficiency of Golgi tendon organs (GTOs) and Ib afferents was observed in distal muscles, as if supernumerary spindles formed at the expense of tendon organs in the absence of Er81. Thus, ER81 may be involved in mechanisms that regulate acquisition of the Ia and Ib phenotypes by subsets of proprioceptive muscle afferents. Segmental differences in muscle spindle and GTO dependence on ER81 suggest that more than one ETS transcription factor may participate in the regulation of limb proprioceptive system assembly in the mouse.

Alleles↗

PubMed2002

Level and origin of iodine-129 in the Baltic Sea.

Environmental samples, such as seawater, seaweed, lake water, lake sediment and grass collected from the Baltic Sea area were analyzed for 129I and 127I by radiochemical neutron activation analysis. In 2000, the concentration of 129I in the seawater from Borholm and Møen in the Baltic Sea has reached 6.0 x 10(-13) and 16 x 10(-13) g/l, respectively, these are more than two orders of magnitude higher than the global fallout level. The highest value of 270 x 10(-13) g/l being found in the seawater from the Kattegat. By comparison of the level of 129I in the lake water and precipitation in this region, it is estimated that more than 95% of 129I in the Baltic Sea originates from reprocessing emissions, especially from the French nuclear fuel reprocessing plant at La Hague. More than 30% of 129I in the south Baltic and 93% in the Kattegat directly originates from the marine discharges of the European reprocessing plants.

Baltic States↗

PubMed2002

[Pseudo-hydrothorax in peripheral venous catheterization in an extremely premature neonate--case report].

The authors describe very rare complication (pseudopleural effusion) after peripheral venous cannulation (Introcan-W 24G3/4 through v. axilaris) in extremely premature newborn with birth weight 600 grams, which lead to worsening of patient's respiratory insufficiency. Ultrasonographic examination confirmed extrapleural process without necessity of surgical intervention. Cannula extraction and infusion interruption were followed by spontaneous regression of the complication, thereafter artificial ventilation was discontinued and baby was discharged.

Axillary Vein↗

PubMed2001

The transcription factor Egr3 modulates sensory axon-myotube interactions during muscle spindle morphogenesis.

The Egr family of zinc-finger transcription factors, consisting of Egr1, Egr2, Egr3, and Egr4, are involved in cellular growth and differentiation. Adult Egr3-deficient mice are ataxic and lack muscle spindle proprioceptors that normally develop at the sites of Ia afferent-myotube contacts during embryogenesis. To resolve whether spindles form and then degenerate, or whether they never form in the absence of Egr3, we examined the spatiotemporal expression of Egr3 relative to spindle development. In wild type mice, Egr3 was expressed in developing myotubes shortly after they were innervated by Ia afferents and its expression was controlled by innervation because it dissipated following nerve transection. In Egr3-deficient mice, myotubes received Ia afferent innervation and assembled normally into spindles during embryogenesis. However, newborn Egr3-deficient spindles had few internal myonuclei in intrafusal fibers and thin capsules. Moreover, slow-developmental myosin heavy chain was not induced in embryonic Egr3-deficient spindles suggesting that impairments in differentiation were present before they could be detected morphologically. After birth, sensory and motor innervation withdrew from the Egr3-deficient spindles, and the spindles disassembled. In spite of the spindle disassembly and retraction of afferents from muscles, the cell bodies of proprioceptive neurons within dorsal root ganglia were retained. We conclude that Egr3 has an essential role in regulating genes required for the transformation of undifferentiated myotubes into intrafusal fibers, and hence for the phenotypic differentiation of spindles.

Afferent Pathways↗

PubMed2001

Evaluation of nigrostriatal dopaminergic function in adult +/+ and +/- BDNF mutant mice.

Deletion of a single copy of the BDNF gene has been shown to affect the nigrostriatal dopaminergic system of young adult BDNF mice. In the present report we evaluated various indices of nigrostriatal dopaminergic function between 9-month-old wild-type (+/+) and heterozygous (+/-) BDNF mutant mice. Performance in a sensorimotor beam walking task was significantly decreased in +/- mice as indicated by increased times required to traverse both a wide (21 mm) and narrow (6 mm) beam. No differences in spontaneous locomotor behavior were observed between the +/+ and +/- mice. Amphetamine-stimulated (5 mg/kg) locomotor behavior was increased to a greater degree in the +/- mice, with the number of movements performed by these mice being significantly greater than their +/+ controls. Corpus striatal dopamine concentrations were significantly greater in the +/- BDNF mice. The absence of any significant differences for dopamine concentrations within the hypothalamus and olfactory bulb of these mice, as well as an absence of any difference in striatal norepinephrine concentrations, suggested a relative specificity of these effects to the corpus striatum. Both the +/- and +/+ mice showed similar reductions in striatal dopamine concentrations in response to a neurotoxic regimen of methamphetamine (20 mg/kg). Collectively these data show increased levels of striatal dopamine concentrations associated with altered behavioral responses involving the nigrostriatal dopaminergic system within the heterozygous BDNF mutant mice.

Animals↗