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Biomedical subjects

J Kucera

Publications and source records attributed to J Kucera.

At least 73 records · Page 4Linked to original sources
PubMed1996

Effects of hemodialysis on bone mineral as followed by using neutron activation analysis.

The purpose of the study was to bring a contribution to the knowledge of physiology and pathophysiology of the bone mineral heteroionic exchange with respect to sodium ions and metabolic diseases, particularly bone diseases. The instrumental neutron activation analysis was employed to follow the ratio of contents Na/Ca in bone samples from dialyzed patients. A formerly elaborated method for the determination of the Na/Ca ratio in undecalcified bone tissue sections obtained from material embedded in polymethylmethacrylate was used. In the reference group the Na/Ca ratio was of 0.021 +/- 0.003, that in patients with the renal osteopathy was of 0.030 +/- 0.007. Results obtained in patients with different types of the renal osteopathy depending on the intensity of the impairment were discussed.

Adolescent↗
PubMed1995

Dependence of developing group Ia afferents on neurotrophin-3.

At birth, group Ia proprioceptive afferents and muscle spindles, whose formation is Ia afferent-dependent, are absent in mice carrying a deletion in the gene for neurotrophin-3 (NT-3-/-). Whether Ia afferents contact myotubes, resulting in the formation of spindles which subsequently degenerate, or whether Ia afferents and spindles never form was examined in NT-3-/- mice at embryonic days (E) 10.5-18.5 by light and electron microscopy. Three sets of data indicate that Ia neurons do not develop and spindles do not form in NT-3-deficient mice. First, peripheral projections of Ia afferents did not innervate hindlimbs of NT-3-/- mice, as reflected by a deficiency of nerve fibers in limb peripheral nerves and an absence of afferent nerve-muscle contacts and spindles in the soleus muscle at E13.5-E18.5. Second, central projections of Ia afferents did not innervate the spinal cord in the absence of NT-3, as shown by an atrophy of the dorsal spinal roots and absence of afferent projections from limb musculature to spinal motor neurons at E13.5 or E15.5. Lastly, the lumbar dorsal root ganglia (DRGs) at E10.5-E14.5, the stages of development that precede or coincide with the innervation of the spinal cord and hindlimbs by Ia afferents, were 20-64% smaller in mutant than in wild-type mice, presumably because the cell bodies of Ia neurons were absent in embryos lacking NT-3. The failure of Ia neurons to differentiate and/or survive and Ia afferent projections to form in early fetal mice lacking NT-3 suggests that NT-3 may regulate neuronal numbers by mechanisms operating prior to neurite outgrowth to target innervation fields. Thus, developing Ia neurons may be dependent on NT-3 intrinsic to the DRGs before they reach a stage of potential dependence on NT-3 retrogradely derived from skeletal muscles or spinal motor neurons.

Animals↗
PubMed1995

Review of trace elements in blood, serum and urine for the Czech and Slovak populations and critical evaluation of their possible use as reference values.

The availability of accurate trace element reference values in human tissues represents an important indicator to the health status of the general population and occupational groups exposed to trace elements. The EURO TERVIHT project (Trace Element Reference Values in Human Tissues) aims to establish and compare trace element reference values in tissues from inhabitants of the European countries as baseline values for clinical/toxicological assessment studies. In this context, one of the first steps considered is the critical evaluation (state of the art) of existing literature on trace element reference values in blood, serum and urine in the general population of each European country. This paper reviews the Czech and Slovak situation by assessing studies carried out in these countries for Al, As, Cd, Co, Cr, Cu, F, Mn, Hg, Ni, Pb, Rb, Sc, Se, V and Zn in blood, serum and urine. These studies show that most of the data available do not meet criteria designed recently for deriving reference intervals, especially regarding the number of subjects, the age of population sample studies as well as the use of appropriate sampling techniques and quality assurance procedures. Elements which present the highest potential risk for health in Czech and Slovak populations and for which reference values should be urgently established are: Cd, Hg, Pb (major pollutants); As, Cr, Ni (carcinogenic metals); Al, F, Mn, Tl, V (released into the environment by coal combustion and other industrial activities); Pt (increasing use of Pt catalyst in petrol-driven automobiles); essential trace elements such as I, Se and Zn for which a deficiency in Czech and Slovak populations was detected or is suspected.

Czechoslovakia↗
PubMed1995

An immunocytochemical marker for early type I muscle fibers in the developing rat hindlimb.

Muscle fibers develop sequentially from several generations of myotubes that express specific isoforms of myosin heavy chain (MHC). We observed that the chicken-derived monoclonal antibody (mAb) S46 binds to myotubes of the fetal rat hindlimb in a specific temporal and spatial pattern. To determine the type and fate of the S46-reactive myotubes, we immunoreacted sections of fetal, neonatal and postnatal hindlimb muscles to this antibody. The mAb S46 bound to a subpopulation of primary myotubes in the tibialis anterior, and to all primary and slow/fast secondary myotubes in the soleus muscle. The S46-reactive primary myotubes represented the oldest set of myotubes in the muscles. Reactivity to S46 was present from the earliest stages of muscle development, peaked in the late fetal period, and dissipated in the first postnatal week, suggesting that mAb S46 binds to a developmental form of slow myosin. The regional distribution of myotubes that bound S46 in fetal muscles was identical to the distribution of type I (slow-twitch) fibers in the adult, indicating that S46-reactive myotubes ultimately develop into type I extrafusal fibers. Thus, mAb S46 can be used as a marker for prospective type I extrafusal fibers in the rat hindlimb.

Animals↗
PubMed1995

Origin of intrafusal fibers from a subset of primary myotubes in the rat.

S46, a monoclonal antibody (mAb) specific for the SM-1 and SM-2 isoforms of avian slow myosin heavy chains (MHC), was used to study the earliest stages of development of intrafusal fibers in muscle spindles of the rat hindlimb. Spindles formed only in the regions of fetal muscles that contained primary myotubes reactive to mAb S46, such as the axial region of the tibialis anterior muscle. The first intrafusal fiber to form, the nuclear bag2 fiber, originated from within the population of S46-reactive primary myotubes. Binding of mAb S46 by myotubes giving rise to the bag2 fibers preceded the appearance of encapsulated spindles in the muscles by electron microscopy. However, reactivity to S46 intensified in the myotubes transforming into bag2 fibers after the innervation of the fibers by afferents, and dissipated in myotubes differentiating into slow-twitch (type I) extrafusal fibers. Thus, afferents may enhance intrafusal expression of the MHC isoform reactive to mAb S46. The pattern of S46 binding to nuclear bag and chain intrafusal fibers in both developing and adult spindles was the same as that reported for the mAb ALD19, suggesting that both antibodies bind to the same MHC isoform. This isoform is probably a developmental form of slow myosin, because it was transiently expressed during the development of type I extrafusal fibers. The origin of bag2 intrafusal and type I extrafusal fibers from a bipotential subpopulation of primary myotubes reactive to mAb S46 correlates with the location of muscle spindles in the slow regions of muscles in adult rat hindlimbs.

Animals↗
PubMed1995

Immediate free flap reconstruction of traumatic defects.

In a series of 180 transfers of free flaps were in 11 cases on upper extremities applied emergency flaps, both for immediate reconstruction of function and for the replacement and covering of tissue defects. In one case a scapular flap was used simultaneously with the replantation of the forearm. In three cases was applied a forearm flap for the reconstruction of the thumb and of the scalped index finger, and in three cases a central venous flap for traumatic defects of tissues on fingers. These flaps yielded surprisingly good functional results after an injury associated with a loss of dorsal aponeurosis of fingers and with an exposure of IP joints. A toe-to-hand transfer was used in one case for the reconstruction of the thumb. A groin flap and a lateral arm flap were applied for the covering of tissue defects.

Adolescent↗
PubMed1995

Studies on the physiological role of brain-derived neurotrophic factor and neurotrophin-3 in knockout mice.

Brain-derived neurotrophic factor and neurotrophin-3 deficient mice were generated by gene targeting. The analysis of these mice has led to the characterization of their role in the survival of neurons in the peripheral nervous system. NT-3 deficient mice displayed severe movement defects and most died shortly after birth. The mutation causes loss of substantial portions of cranial and spinal peripheral sensory and sympathetic neurons. Significantly, spinal proprioceptive afferents and their peripheral sense organs (muscle spindles and Golgi tendon organs) were completely absent in homozygous mutant mice. BDNF deficient mice displayed deficiencies in coordination and balance. Excessive loss of neurons was detected in most of the peripheral sensory ganglia examined, but the survival of sympathetic neurons was not affected. The most marked reduction of neurons was observed in the vestibular ganglion, leading to a loss of innervation of the sensory epithelia of the vestibular compartments of the inner ear.

Afferent Pathways↗
PubMed1994

Lack of neurotrophin-3 leads to deficiencies in the peripheral nervous system and loss of limb proprioceptive afferents.

Neurotrophin-3-deficient (NT-3-deficient) mice were generated by gene targeting. Mutant mice displayed severe movement defects of the limbs, and most died shortly after birth. Substantial portions of peripheral sensory and sympathetic neurons were lost while motor neurons were not affected. Significantly, spinal proprioceptive afferents and their peripheral sense organs (muscle spindles and Golgi tendon organs) were completely absent in homozygous mutant mice. This correlated with a loss of parvalbumin and carbonic anhydrase-positive neurons in the dorsal root ganglion. No gross abnormalities were seen in Pacinian corpuscles, cutaneous afferents containing substance P and calcitonin gene-related peptide, and deep nerve fibers in the joint capsule and tendon. Importantly, the number of muscle spindles in heterozygous mutant mice was half of that in control mice, indicating that NT-3 is present at limiting concentrations in the embryo.

Animals↗
PubMed1994

Sequences of intrafusal fiber formation are muscle-dependent in rat hindlimbs.

A rat muscle spindle typically contains four intrafusal fibers-one nuclear bag2, one nuclear bag1 and two nuclear chain fibers. We compared the sequence of formation of the three intrafusal fiber types among the tibialis anterior (TA), soleus (SOL) and medial gastrocnemius (MG) muscles using immunocytochemistry of spindle-specific myosin heavy chain isoforms. Spindles of the TA began to differentiate earlier and acquired the full complement of intrafusal fibers sooner than spindles of the SOL or MG muscles. At the onset of spindle assembly, the intrafusal myotubes expressed myosin heavy chains similar to those expressed by extrafusal myotubes. The first intrafusal myotube then differentiated into the bag2 fiber regardless of the muscle. However, the fate of the second-forming intrafusal myotube varied among the muscles studied. It usually differentiated into a chain fiber in the TA, into a bag1 fiber in the SOL, and into either a bag1 or a chain in the MG. The fate of the third-forming intrafusal myotube was reciprocal to that of the second; i.e. in those spindles in which the bag1 fiber was second to form, a chain was third, and vice versa. The fourth and last intrafusal myotube gave rise to a chain fiber. The inter- and intramuscular variability in the fate of intrafusal myotubes of the second and third generation argues against the existence of a program intrinsic to the myotubes that would mandate their differentiation along specific paths. Rather, an extrinsic regulatory factor, probably associated with the primary afferent neuron, may govern differentiation of pluripotential myotubes into particular types of intrafusal fiber. The fate of the intrafusal myotubes might then depend on the timing of the regulatory effect of afferents relative to the stage of development of the intrafusal bundle.

Animals↗
PubMed1994

Determination of sodium-to-calcium ratio in mouse femora by INAA.

Within the scope of the study of the heteroionic exchange in the bone mineral, the sodium-to-calcium ratio was established in femora of 55 male ICR mice. The purpose of the work was to establish the precision of the method as well as biological variations, since the authors intend to investigate the sodium-to-calcium ratio on pathophysiological models in the future with a special regard to osteoporosis. The resulting mean value was of 0.02515 +/- 0.00053. The small standard deviation indicates that the ratio is not subject to considerable individual variations. The accuracy of the method was checked by analyzing the reference bone sample IAEA H-5. The results obtained exerted a good agreement with the certified sodium and calcium concentrations.

Animals↗
PubMed1994

Vanadium levels in urine and cystine levels in fingernails and hair of exposed and normal persons.

Vanadium was determined by radiochemical neutron activation analysis (RNAA) with proven accuracy in urine of workers occupationally exposed to vanadium-rich dust in a vanadium pentoxide production plant, and values in the range of 3.02-762 ng/mL (median 33.0 ng/mL) were found. In a control group consisting of administrative workers of the plant, urinary vanadium levels were found in the range of 1.05-53.4 ng/mL (median 2.53 ng/mL), whereas in an another control group of occupationally nonexposed persons, these values amounted to 0.066-0.489 ng/mL (median 0.212 ng/mL). Accuracy of the results was tested by analysis of reference material IAEA A-13 Animal Blood and NIST SRM-1515 Apple Leaves, and very good agreement was found with literature and the NIST certified values, respectively. Unlike urine, no significant differences were found for cystine levels in fingernails and hair of exposed and control persons.

Adult↗
PubMed1994

Interlaboratory analysis of IRM NSC-21 Compost Vitahum.

The preparation of internal reference material NSC-21 Compost Vitahum, including its stabilization, homogeneity testing, and evaluation of an interlaboratory comparison in which 19 laboratories took part using several analytical methods is described. From the results of the intercomparison, consensus values were derived for the contents of Cd, Cu, Ni, Pb, and Zn, whereas for As, Co, Cr, Fe, Hg and Mn, information values were derived. Bimodal distribution of the As and Cr results was obtained, presumably because of incomplete dissolution of the elements from the matrix if insufficiently aggressive decomposition procedures were employed. Some problems encountered were elucidated by application of neutron activation analysis (NAA) in its nondestructive and destructive (radiochemical) modes.

Industrial Waste↗
PubMed1994

Social anxiety in schizophrenia.

The relationship between social anxiety and positive and negative symptomatology in schizophrenia was investigated. Thirty eight inpatients with schizophrenia completed a battery of self-report measures of anxiety, a modified Stroop task, and an unstructured role play. Positive symptoms were related to fear in a number of self-report domains (i.e., social and agoraphobic). Negative symptoms were related to global observational ratings of anxiety during the role play as well as specific behaviors associated with self-reported social anxiety (i.e., speech rate and fluency). Positive symptoms generally were not associated with role play ratings. Thus, specific behaviors related to social anxiety appear to be associated with negative symptoms, while self-report is associated with positive symptoms. Problems in the assessment of social anxiety in individuals with schizophrenia and implications of these findings for social skills training in this population are discussed.

Adult↗
PubMed1994

Microsurgical reconstruction of traumatic defects on the lower extremities.

Out of 167 free transfers 90 were applied to the lower extremities, i.e. 75 for injuries, 11 for an osteomyelitis and 4 for cancer. For these transfers were used the following 15 types of flaps; 37 from the forearm, 15 m. latissimus, 12 m. serratus ant. sup., 6 scapular, 4 fibula, 4 from the groin, 2 gracilis, 2 LAF, 1 TFL, 1 TRAM, 1 dorsalis pedis, 1 sartorius, 1 crista iliaca, 1 rectus abdominis, 1 combined latissimus+serratus. The transfer of flaps was satisfactory in 92%. The transfers to the lower extremity included in no case an emergency flap, in the acute phase within 7 days after injury were transferred 5 flaps. There were in addition 32 delayed and 38 secondary flaps. The report deals with important principles of the application of the above described transfers.

Adolescent↗
PubMed1994

Expression of estrogen receptors and estrogen-induced proteins in tumors of "hormone non-dependent tissues".

Estrogen receptors (ER), progesterone receptors (PR) and some other estrogen-induced proteins (EIP) were found in the cells of salivary gland carcinomas, thyroid carcinomas, in gliomas and in various farther neoplasms as well as in some normal tissues. The positivity was demonstrated in both females and males. The results indicate that steroid hormones and their receptors could play, both in normal and tumorous tissues, more important biological role than expected so far.

Adult↗