Biomedical subjects

C Jung

Publications and source records attributed to C Jung.

At least 19 recordsLinked to original sources

PubMed2006

Ca2+ release from the sarcoplasmic reticulum activated by the low affinity Ca2+ chelator TPEN in ventricular myocytes.

The Ca2+ content of the sarcoplasmic reticulum (SR) of cardiac myocytes is thought to play a role in the regulation and termination of SR Ca2+ release through the ryanodine receptors (RyRs). Experimentally altering the amount of Ca2+ within the SR with the membrane-permeant low affinity Ca2+ chelator TPEN could improve our understanding of the mechanism(s) by which SR Ca2+ content and SR Ca2+ depletion can influence Ca2+ release sensitivity and termination. We applied laser-scanning confocal microscopy to examine SR Ca2+ release in freshly isolated ventricular myocytes loaded with fluo-3, while simultaneously recording membrane currents using the whole-cell patch-clamp technique. Following application of TPEN, local spontaneous Ca2+ releases increased in frequency and developed into cell-wide Ca2+ waves. SR Ca2+ load after TPEN application was found to be reduced to about 60% of control. Isolated cardiac RyRs reconstituted into lipid bilayers exhibited a two-fold increase of their open probability. At the low concentration used (20-40microTPEN did not significantly inhibit the SR-Ca2+-ATPase in SR vesicles. These results indicate that TPEN, traditionally used as a low affinity Ca2+ chelator in intracellular Ca2+ stores, may also act directly on the RyRs inducing an increase in their open probability. This in turn results in an increased Ca2+ leak from the SR leading to its Ca2+ depletion. Lowering of SR Ca2+ content may be a mechanism underlying the recently reported cardioprotective and antiarrhythmic features of TPEN.

Animals↗

PubMed2006

Introgression of genomic components from Chinese Brassica rapa contributes to widening the genetic diversity in rapeseed (B. napus L.), with emphasis on the evolution of Chinese rapeseed.

In spite of its short history of being an oil crop in China, the Chinese semi-winter rapeseed (Brassica napus L., 2n = 38, AACC) has been improved rapidly by intentional introgression of genomic components from Chinese B. rapa (2n = 20, AA). As a result, the Chinese semi-winter rapeseed has diversified genetically from the spring and winter rapeseed grown in the other regions such as Europe and North America. The objectives of this study were to investigate the roles of the introgression of the genomic components from the Chinese B. rapa in widening the genetic diversity of rapeseed and to verify the role of this introgression in the evolution of the Chinese rapeseed. Ten lines of the new type of rapeseed, which were produced by introgression of Chinese B. rapa to Chinese normal rapeseed, were compared for genetic diversity using amplified fragment length polymorphism (AFLP) with three groups of 35 lines of the normal rapeseed, including 9 semi-winter rapeseed lines from China, 9 winter rapeseed lines from Europe and 17 spring rapeseed lines from Northern Europe, Canada and Australia. Analysis of 799 polymorphic fragments revealed that within the groups, the new type rapeseed had the highest genetic diversity, followed by the semi-winter normal rapeseed from China. Spring and winter rapeseed had the lowest genetic diversity. Among the groups, the new type rapeseed group had the largest average genetic distance to the other three groups. Principal component analysis and cluster analysis, however, could not separate the new type rapeseed group from Chinese normal rapeseed group. Our data suggested that the introgression of Chinese B. rapa could significantly diversify the genetic basis of the rapeseed and play an important role in the evolution of Chinese rapeseed. The use of new genetic variation for the exploitation of heterosis in Brassica hybrid breeding is discussed.

Brassica napus↗

PubMed2006

Partitioning the phase space in a natural way for scattering systems.

In this paper, we demonstrate a recent procedure for the construction of a symbolic dynamics for open systems by applying it to a model potential, the driven inverted Gaussian, which has proven very useful in describing laser-atom interaction. The symbolic dynamics and the corresponding partition of the Poincaré map are natural from the point of view of an asymptotic observer since the resulting branching tree coincides with the one extracted from the scattering functions. In general, the whole procedure is approximate because it only describes the globally unstable part of the chaotic invariant set, that is, the part that can be seen by an asymptotic observer in scattering data. It ignores Kolmogorov-Arnold-Moser islands and their fractal surroundings.

Journal Article↗

PubMed2006

Phaeochromocytoma in pregnancy.

Hypertension during pregnancy is a common problem, causing significant maternal and fetal morbidity and mortality. Pre-eclampsia is by far the most common cause, affecting 5-10% of primigravid women. Phaeochromocytoma is a rare endocrine tumour causing hypersecretion of noradrenaline, adrenaline and/or dopamine. It is extremely rare during pregnancy and may be misdiagnosed with potentially catastrophic consequences. Delayed diagnosis remains a significant source of maternal and fetal morbidity and mortality. Recognition is critical, as the majority of maternal deaths have occurred when the diagnosis has been overlooked. Diagnosis of phaeochromocytoma is achieved by detecting increased catecholamines and metabolites (metanephrine and normetanephrine) on 24-h urine collection, as these levels are unaffected by pregnancy or pre-eclampsia. Definitive treatment of phaeochromocytoma is surgical and the laparoscopic approach has been shown to be safe and is preferred for most phaeochromocytomas. Medical preparation and treatment of hypertension is essential for safe surgery. Timing of adrenalectomy is either during the second trimester or as a staged procedure after Caesarean section delivery.

Adrenal Gland Neoplasms↗

PubMed2005

HOXB13 is downregulated in colorectal cancer to confer TCF4-mediated transactivation.

Mutations in the Wnt signalling cascade are believed to cause aberrant proliferation of colorectal cells through T-cell factor-4 (TCF4) and its downstream growth-modulating factors. HOXB13 is exclusively expressed in prostate and colorectum. In prostate cancers, HOXB13 negatively regulates beta-catenin/TCF4-mediated transactivation and subsequently inhibits cell growth. To study the role of HOXB13 in colorectal tumorigenesis, we evaluated the expression of HOXB13 in 53 colorectal tumours originated from the distal left colon to rectum with their matching normal tissues using quantitative RT-PCR analysis. Expression of HOXB13 is either lost or diminished in 26 out of 42 valid tumours (62%), while expression of TCF4 RNA is not correlated with HOXB13 expression. TCF4 promoter analysis showed that HOXB13 does not regulate TCF4 at the transcriptional level. However, HOXB13 downregulated the expression of TCF4 and its target gene, c-myc, at the protein level and consequently inhibited beta-catenin/TCF-mediated signalling. Functionally, forced expression of HOXB13 drove colorectal cancer (CRC) cells into growth suppression. This is the first description of the downregulation of HOXB13 in CRC and its mechanism of action is mediated through the regulation of TCF4 protein stability. Our results suggest that loss of HOXB13 may be an important event for colorectal cell transformation, considering that over 90% of colorectal tumours retain mutations in the APC/beta-catenin pathway.

Cell Proliferation↗

PubMed2005

Bacterial artificial chromosome-derived molecular markers for early bolting in sugar beet.

Early bolting in sugar beet (Beta vulgaris L.) is controlled by the dominant gene B. From an incomplete physical map around the B gene, 18 bacterial artificial chromosomes (BACs) were selected for marker development. Three BACs were shotgun-sequenced, and 61 open reading frames (ORFs) were identified. Together with 104 BAC ends from 54 BACs, a total number of 55,464 nucleotides were sequenced. Of these, 37 BAC ends and 12 ORFs were selected for marker development. Thirty-one percent of the sequences were found to be single copy and 24%, low copy. From these sequences, 15 markers from ten different BACs were developed. Ten polymorphisms were determined by simple agarose gel electrophoresis of either restricted or non-restricted PCR products. Another five markers were determined by tetra-primer amplification refractory mutation system-PCR. In order to select candidate BACs for cloning the gene, genetic linkage between seven markers and the bolting gene was calculated using 1,617 plants from an F2 population segregating for early bolting. The recombination values ranged between 0.0033 and 0.0201. In addition, a set of 41 wild and cultivated Beta accessions differing in their early bolting character was genotyped with seven markers. A common haplotype encompassing two marker loci and the b allele was found in all sugar beet varieties, indicating complete linkage disequilibrium between these loci. This suggests that the bolting gene is located in close vicinity to these markers, and the corresponding BACs can be used for cloning the gene.

Base Sequence↗

PubMed2005

A genetic linkage map of Lens sp. based on microsatellite and AFLP markers and the localization of fusarium vascular wilt resistance.

Microsatellites have currently become the markers of choice for molecular mapping and marker-assisted selection for key traits such as disease resistance in many crop species. We report here on the mapping of microsatellites which had been identified from a genomic library of lentil (Lens culinaris Medik.). The majority of microsatellite-bearing clones contained imperfect di-nucleotide repeats. A total of 41 microsatellite and 45 amplified fragment length polymorphism (AFLP) markers were mapped on 86 recombinant inbred lines derived from the cross ILL 5588 x L 692-16-1(s), which had been previously used for the construction of a random amplified polymorphic DNA and AFLP linkage map. Since ILL 5588 was resistant to fusarium vascular wilt caused by the fungus Fusarium oxysporum Shlecht. Emend. Snyder & Hansen f.sp. lentis Vasud. & Srini., the recombinant inbreds were segregating for this character. The resulting map contained 283 markers covering about 751 cM, with an average marker distance of 2.6 cM. The fusarium vascular wilt resistance was localized on linkage group 6, and this resistance gene was flanked by microsatellite marker SSR59-2B and AFLP marker p17m30710 at distances of 8.0 cM and 3.5 cM, respectively. These markers are the most closely linked ones known to date for this agronomically important Fw gene. Using the information obtained in this investigation, the development and mapping of microsatellite markers in the existing map of lentil could be substantially increased, thereby providing the possibility for the future localization of various loci of agronomic interest.

Chromosome Mapping↗

PubMed2005

Multi-frequency EPR and Mössbauer spectroscopic studies on freeze-quenched reaction intermediates of nitric oxide synthase.

It is believed by analogy to chloroperoxidase (CPO) from Caldariomyces fumago that the electronic structure of the intermediate iron-oxo species in the catalytic cycle of nitric oxide synthase (NOS) corresponds to an iron(IV) porphyrin-pi -cation radical. Such species can also be produced by the reaction of ferric NOS with external oxidants within the shunt pathway. We present multi-frequency EPR (9.6, 94, 285 GHz) and Mössbauer spectroscopic studies on freeze-quenched intermediates of the oxygenase domain of nitric oxide synthase which has reacted with peroxy acetic acid within 8-200 ms. The intermediates of the oxygenase domain of both the cytokine inducible NOS (iNOSox) and the neuronal NOS (nNOSox) show an organic radical signal in the 9.6-GHz spectrum overlapping with the spectrum of an unknown species with g-values of 2.24, 2.23 and 1.96. Using 94- and 285-GHz EPR the organic radical signal is assigned to a tyrosine radical on the basis of g-values (i.e. Tyr*562 in nNOSox and Tyr*341 in iNOSox). Mössbauer spectroscopy of (57)Fe-labeled unreacted nNOSox shows a ferric low-spin heme-iron (delta = 0.38 mms(-1), deltaE(Q) = 2.58 mms(-1)). The reaction of nNOSox with peroxy acetic acid for 8 ms leads to the disappearance of the magnetic background characteristic for native nNOSox and a new species with delta = 0.27 mms(-1) and deltaE(Q) = 2.41 mms(-1) is detected at 4.2 K which does not resemble the parameters typical for a Fe(IV) center. It is proposed that this intermediate species corresponds to a ferric low-spin species which magnetically couples to an amino acid radical (presumably Trp*409).

Binding Sites↗

PubMed2005

Low-temperature FTIR spectra and hydrogen bonds in polycrystalline adenosine and uridine.

FTIR spectra of polycrystalline samples of adenosine and uridine, pure and containing small (<10%) quantity of N(O)H or N(O)D groups, were measured in KBr pellets from 4000 to 400 cm(-1) at temperatures from 300 to 20 K. For the first time, the bands of narrow isotopically decoupled proton stretching vibration nu1 mode of NH- and OH- groups were found and assigned to ordered hydrogen bonds according to crystal structural data for both nucleosides. The FTIR adenosine spectra in the out-of-plane bending proton nu4 mode range (lower than 1000 cm(-1)) of N(O)H groups revealed at low temperature at least twice more bands, than in the nu1 range, which are influenced by isotopic exchange and (or) cooling. Almost all of them have their counterparts in the N(O)D substance spectrum with an isotopic frequency ratio of 1.30-1.40. These bands were assigned to the differently H-bound disordered NH and OH protons, which could not be seen with crystal structural methods. The energy and length of different H-bonds were estimated from peak positions of both mode bands (as the red shift of nu1 or blue shift of nu4 relatively free molecules) with well-established empirical correlations between spectral, thermodynamic and structural parameters of hydrogen bonds. The results were compared with independent experimental data.

Adenosine↗

PubMed2005

Construction of a natural partition of incomplete horseshoes.

We present a method for constructing a partition of an incomplete horseshoe in a Poincare map. The partition is based only on the unstable manifolds of the outermost fixed points and eventually their limits. Consequently, this partition becomes natural from the point of view of asymptotic scattering observations. The symbolic dynamics derived from this partition coincides with the one derived from the hierarchical structure of the singularities of the scattering functions.

Journal Article↗

PubMed2005

In vitro culture decreases the expression of TGF(beta), Hsp47 and type I procollagen and increases the expression of CTGF in avian tendon explants.

Weight-bearing tendons in many species, including humans, chickens and horses, are prone to failure, in many cases without a discernible cause. The normal function of the tendon depends on the proper assembly of fibrils of type I collagen, the main structural component of the tendon. We studied the effect of in vitro culture, temperature (37 degrees C vs. 43 degrees C) and wounding on the expression of mRNAs for several collagen regulators, transforming growth factor beta (TGF(beta)), heat shock protein 47 (Hsp47) and connective tissue growth factor (CTGF), in chicken embryonic gastrocnemius tendon explants. The expression of mRNAs for TGF(beta) and Hsp47, a chaperone of collagen assembly, remained strong during the first day of in vitro culture, but then it decreased, slightly more at higher temperature. Additional injury in selected tendons had no significant effect on the levels of TGF(beta) and Hsp47 mRNAs. Likewise, the level of immunostained type I procollagen also decreased with the length of culture. The expression of CTGF gradually increased from 0 at the time of tendon removal with the duration of culture to strong after three days of culture when the expression of TGF(beta) and Hsp47 was low. We conclude that in vitro culture over the period of several days rather than an increase in temperature or additional wounding decreases the expression of TGF(beta), Hsp47 and type I procollagen and increases the expression of CTGF.

Animals↗

PubMed2004

Electron-vibron coupling in high-resolution X-Ray absorption spectra of organic materials: NTCDA on Ag(111).

We report additional rich fine structures in high-resolution near-edge x-ray-absorption fine structure (NEXAFS) spectra of large organic molecules using NTCDA on Ag(111) as an example. These fine structures are completely interpreted as vibronic coupling to electronic core excitations. The coupling is mode selective; predominantly one vibronic mode couples to each excitation. The fit results suggest the occurrence of a Davydov splitting, first observed for core excitons. Morphological differences substantially influence the electron-vibron coupling, indicating a strong intermolecular interaction. Thus NEXAFS becomes a more subtle probe for organic solids.

Journal Article↗

PubMed2004

Spectroscopic interpretation: the high vibrations of CDBrClF.

We extract the dynamics implicit in an algebraic fitted model Hamiltonian for the deuterium chromophore's vibrational motion in the molecule CDBrClF. The original model has four degrees of freedom, three positions and one representing interbond couplings. A conserved polyad allows in a semiclassical approach the reduction to three degrees of freedom. For most quantum states we can identify the underlying motion that when quantized gives the said state. Most of the classifications, identifications, and assignments are done by visual inspection of the already available wave function semiclassically transformed from the number representation to a representation on the reduced dimension toroidal configuration space corresponding to the classical action and angle variables. The concentration of the wave function density to lower dimensional subsets centered on idealized simple lower dimensional organizing structures and the behavior of the phase along such organizing centers already reveals the atomic motion. Extremely little computational work is needed.

Journal Article↗

PubMed2004

[The cochlear implant. Molecular arguments favouring early implantation].

BACKGROUND: An important factor in the clinical outcome of cochlear implantation is the age of the patient. Compared to older patients, children with congenital deafness have a better outcome when the implantation is made before the age of 2 years. The cause may lie in the molecular biology of the brain, which changes during postnatal maturation. METHODS: Protein probes were obtained from tissue of the rat inferior colliculus at different ages. The probes were analyzed using 2-dimensional SDS electrophoresis. RESULTS: The expression of GAP-43, a protein expressed by neurons during axonal outgrowth and synaptogenesis, and the total number of the protein species showed a significant reduction during ontogenesis. This shows that while neurons gradually assume their specific function, they downregulate GAP-43 and the molecular complexity decreases. CONCLUSIONS: Due to a lack of neuronal pluripotency at later developmental stages, the flexibility to adapt to the afferent activation provided by a cochlear implant is increasingly limited.

Aging↗

PubMed2004

AIDS, multicentric Castleman's disease, and plasmablastic leukemia: report of a long-term survival.

Plasmablastic leukemia (PL) as a complication of human herpes virus 8 (HHV8)-associated Castleman's disease is marked by a rapid and fatal outcome. In patients with AIDS, survival of 7 to 14 days after diagnosis has been reported. Prompt splenectomy and chemotherapy might lead to a significant survival benefit. Here we report a case of long-term survival in a patient with AIDS and multicentric Castleman's disease (MCD) complicated by PL.

AIDS-Related Opportunistic Infections↗

PubMed2004

Low temperature FTIR spectra and hydrogen bonds in polycrystalline cytidine.

FTIR spectra of polycrystalline samples of cytidine, pure and containing a small quantity of N(O)H or N(O)D groups (<20%), were measured in KBr pellets from 4000 to 400 cm(-1) at temperatures from 300 to 20K. For the first time the bands of the narrow isotopically decoupled proton stretching vibration mode (nu(1)) of OH- and NH- groups were found; their number corresponds to the number of H-bonds in crystal according to structural data. The FTIR spectra at low temperature in the out-of-plane bending nu(4) proton mode range (lower than 1000 cm(-1)) of N(O)H groups revealed narrow bands, which correspond to nu(1) bands together with several "extra" bands, which are influenced by the isotopic exchange and (or) cooling. All of them have their counterparts in the N(O)D-substance spectrum with an isotopic frequency ratio of 1.30-1.40. The "extra" bands are assigned to the H-bound OH and NH protons, which are disordered and cannot be seen with X-ray crystal structure analysis. The peak positions of both mode bands (expressed as the red shift of nu(1) or blue shift of nu(4) modes relatively free molecules) were used for the estimation of the energy of different H-bonds using previously established empirical correlations between spectral and thermodynamic parameters of hydrogen bonds. The correlation of the red shift and H-bond length is also confirmed for all five H-bonds of cytidine.

Cold Temperature↗

PubMed2004

[Quality indicators for ambulatory health education programme for overweight and obese children and adolescents].

BACKGROUND: In Germany, 9 to 12 % of all children between five and seven years of age have been shown to be overweight at school entry; 2.5 to 3.5 % of them are obese. Therapeutic intervention for obese children and adolescents is considered to be indicated especially in cases where an increased body mass index (BMI) is accompanied by a disease the effective treatment of which requires weight loss. Furthermore, the child and its family must be willing to actively change their habits. OBJECTIVE: A multitude of health care providers have begun to offer multidisciplinary group programme for prevention and treatment of obesity to affected individuals and their families. The Medical Service of the Statutory Health Insurance (MDK) has therefore developed a list of quality and assessment criteria for such programme. METHODS: A systematic search for information in international and national publications was performed using standard methodology of evidence-based medicine. Data were extracted and assessed according to pre-defined criteria taking into consideration previously published clinical guidelines and opinions of expert panels. RESULTS: Nearly all available studies were of low internal validity and mostly of poor methodological quality. Therefore, no binding recommendations for the design of health education programme for overweight and obese children and adolescents can be given. Potentially successful intervention should combine the following 4 modules: nutrition, physical activity, change of eating habits, physical activity habits and life style using methods of behavioural therapy, and involvement of parents. Such combinations may have the potential to reduce or stabilise the BMI at least during a defined period of time. In younger children, the beneficial effect will be more pronounced if the parents are actively involved. CONCLUSION: Up to now informative studies have not reliably shown that the effect of ambulatory health education programmes for overweight and obese children and adolescents and their parents may last for more than one or two years. Therefore, a controlled clinical trial determining the long-term effectiveness of such programme is imperative. The decision whether a defined programmes should be included in such a study could be taken on the basis of the quality indicators and assessment criteria described here.

Ambulatory Care↗

PubMed2004

Symmetry properties of periodic orbits extracted from scattering data.

Discrete symmetries of a system are reflected in the properties of the shortest periodic orbits. By applying a recent method to extract these from the scaling of the fractal structure in scattering functions, we show how the symmetries can be extracted from scattering data simultaneously with the periods and the Lyapunov exponents. We pay particular attention to the change of scattering data under a small symmetry breaking.

Journal Article↗