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Biomedical subjects

J Kraus

Publications and source records attributed to J Kraus.

At least 73 records · Page 4Linked to original sources
PubMed1998

Identification of a functional 3',5'-cyclic adenosine monophosphate response element within the second promoter of the mouse somatostatin receptor type 2 gene.

Important physiological actions of somatostatin are mediated by the somatostatin receptor type 2. Its transcription is regulated by three tissue specific, alternative promoters. It is known that the mRNA of the somatostatin receptor type 2 gene is induced by cAMP, but little is known about the mechanisms underlying this regulation. We have identified and characterized a cAMP responsive element located at nucleotide -162 on the second promoter of the gene consisting of the classical palindromic octameric sequence 5'-TGACGTCA-3'. Using transient expression of reporter gene deletion constructs in NGC108-15 cells the necessity of the intact element for forskolin-induced reporter gene activity was demonstrated. The first and the third promoter are not responsive to forskolin, nor did any promoter respond to the phorbol ester PMA. Electrophoretic mobility shift assays in combination with competition experiments suggest the interaction of the promoter element with the cAMP responsive element binding protein.

Animals↗
PubMed1998

Alternative promoter usage and tissue specific expression of the mouse somatostatin receptor 2 gene.

We have cloned the 5' upstream regulatory region of the mouse somatostatin receptor 2 gene. Its genomic organization is novel among all somatostatin receptor genes. It contains two previously unrecognized exons, separated by introns larger than 25 kb, and three tissue and cell specific alternative promoters. The first promoter in front of exon 1 is active only in AtT-20 tumor cells. The second promoter, located 5' to exon 2, is used in brain, pituitary, adrenals, pancreas, NG 108-15 and AtT-20 cells. Furthermore, it contains putative DNA elements for regulation by glucocorticoids, estradiol and cAMP. A third promoter, located in exon 3, is additionally used in lung, kidney and spleen.

Alternative Splicing↗
PubMed1998

Soluble and cell surface ICAM-1 as markers for disease activity in multiple sclerosis.

OBJECTIVE: The intercellular adhesion molecule-1 (ICAM-1) is a member of the Ig supergene family. ICAM-1 is expressed on various cells like peripheral blood lymphocytes, endothelial cells or thymic cells and the cell surface form is supposed to be shed into a soluble form. The expression of ICAM-1 is induced by cytokines like Interleukin-1, TNF alpha or interferon gamma. The aim of the study was to investigate whether changes of cell surface and soluble ICAM-1 in the cerebrospinal fluid (CSF) and blood are indicative for disease activity in patients with multiple sclerosis (MS). MATERIAL AND METHODS: In all patients with relapsing-remitting MS (relapse: n=31, remission: n=11) and controls (n=13) the expression of cell surface ICAM-1 (c-ICAM-1) was determined by two colour flow cytometry. Soluble ICAM-1 (s-ICAM-1) was measured by ELISA. Follow-up examinations were done 3 months later. RESULTS: In 31 patients with a current relapse we found significantly decreased expression levels of c-ICAM-1 on leukocytes in CSF (P<0.001) and blood (P<0.10), when compared to those 11 individuals experiencing remission. In contrast we observed significantly (P<0.05) increased levels of s-ICAM-1 in CSF of patients with relapses. Comparing patients who had been in remission for more than 4 weeks (n=11) with remission lasting longer than 3 months (n=28) we detected stable c-ICAM-1 expression on CD3+ T cells in blood. CONCLUSION: Our results demonstrate for the first time that c-ICAM-1 on CD3+ T-cells in CSF and blood is an activity marker in MS.

Adolescent↗
PubMed1997

Dopamine D1-deficient mutant mice do not express the late phase of hippocampal long-term potentiation.

The possible involvement of the dopamine D1 receptor subtype in mechanisms of long-term potentiation (LTP) of the Schaffer collateral-commissural input of CA1 neurones was investigated using D1-deficient mutant mice. In transversal hippocampus slices from mice lacking the D1 receptor a normal post-tetanic and short-term potentiation could be induced after applying a triple 100 Hz tetanization. However, the potentiated fEPSP in the mutant mice declined to control value about 140 min following tetanization, whereas in the wild type mice a normal, non-decremental LTP was observed. These data support the idea that besides the glutamatergic system, the synergistic activation of dopaminergic synapses is necessary for LTP maintenance.

Animals↗
PubMed1997

Medulloblastomas of the desmoplastic variant carry mutations of the human homologue of Drosophila patched.

Inactivating mutations in the PTCH gene, a human homologue of the Drosophila segment polarity gene patched, have been identified recently in patients with nevoid basal cell carcinoma syndrome. These patients are predisposed to various neoplasias including basal cell carcinomas and medulloblastomas (MBs). To determine the involvement of PTCH in sporadic MBs, which represent the most frequent malignant brain tumors in children, we screened for PTCH alterations in an unselected panel of 64 biopsy samples from 62 patients and four continuous MB cell lines, all derived from patients with sporadic MBs. Using single-strand conformational polymorphism analysis, we screened exons 2-22 and detected nonconservative PTCH mutations in 3 of 11 samples from sporadic cases of the desmoplastic variant of MB but none in 57 MBs with classical (nondesmoplastic) histology. In two of the tumors with mutations and in two additional desmoplastic cases, loss of heterozygosity was found at 9q22. These findings suggest that PTCH represents a tumor suppressor gene involved in the development of the desmoplastic variant of MB.

Adolescent↗
PubMed1997

Acute work injuries among electric utility linemen.

This analysis presents differences in acute work injury rates among electric utility linemen who perform different work tasks. Incidence-density rate ratios were the primary measure of association and are based on the work injury and person-time data for each job title. Logistic regression was used to model race, age, job experience, total inservice, prior injury, and time from prior injury. Transmission linemen had the lower acute injury rate with 18.9 per 100 person-work-years (95% CI 16-20), distribution linemen had 27.8 per 100 person-work-years (95% CI 27-28), and apprentice linemen had 43.3 per 100 person-work-years (95% CI 41-45). Injuries to the trunk and sprains and strains are the predominant injury categories. Having a prior lost time injury increases the risk for subsequent lost time injury for transmission linemen (OR = 1.6, 95% CI = 1.0-2.7) and for distribution linemen (OR = 1.5, 95% CI = 1.3-1.6).

Absenteeism↗
PubMed1997

High-resolution comparative hybridization to combed DNA fibers.

Comparative genomic hybridization (CGH) has proven to be a comprehensive new tool to detect genetic imbalances in genomic DNA. However, the resolution of this method carried out on normal human metaphase spreads is limited to low copy number gains and losses of > or = 10 Mb. An improved resolution allowing the detection of copy number representations of single genes would strongly enhance the applicability of CGH as a diagnostic and research tool. This goal may be achieved when metaphase chromosomes are replaced by an array of target DNAs representing the genes of interest. To explore the feasibility of such a development in a model system we used cosmid MA2B3, which encompasses about 35 kb in the vicinity of exon 48 of the human dystrophin gene. Linearized cosmid fibers were attached to a glass surface and aligned in parallel by "molecular combing". Two-color fluorescence in situ suppression hybridization was performed on these cosmid fibers with probe mixtures containing different ratios (ranging from 1:2 to 4:1) of biotin- and digoxigenin-labeled MA2B3 cosmid DNAs. For each mixture fluorescence ratios were determined for 40-50 individual combed DNA molecules. In two series comprising a total of 651 molecules the median fluorescence ratio measurements revealed a linear relationship with the chosen probe ratios. Our study demonstrates that fluorescence ratio measurements on single DNA molecules can be performed successfully.

Biotin↗
PubMed1997

Removal of repetitive sequences from FISH probes using PCR-assisted affinity chromatography.

The vast majority of probes used in fluorescence in situ hybridization (FISH) contain repetitive DNA. This DNA is usually competed out of a hybridization reaction by the addition of an unlabeled blocking agent, Cot-1 DNA. We have successfully removed repetitive DNA from two complex FISH probe sets: a degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR) single human chromosome library and genomic DNA. The procedure involved hybridizing in solution a DOP-PCR-amplifiable probe set with a 50-fold excess of biotin-labeled Cot-1 DNA, and capturing the Cot-1 DNA-containing hybrids using streptavidin magnetic particles, followed by purification and reamplification of the unbound fraction. Probes were checked for depletion of repeats by hybridization to chromosomes without Cot-1 DNA. Results showed hybridization patterns comparable to those achieved with untreated probes hybridized with Cot-1 DNA.

Chromatography, Affinity↗
PubMed1997

Neuronal ceroid lipofuscinosis in the Czech Republic: analysis of 57 cases. Report of the 'Prague NCL group'.

A series of 57 patients (from 51 families) with neuronal ceroid lipofuscinosis (NCL) has been diagnosed during the last 25 years. Using clinical and electrophysiological criteria together with results of ultrastructural, histochemical, immunohistochemical and neuropathological analyses it has been possible to classify the following NCL types. Two cases were of the infantile type (CLN1), one case of the juvenile (CLN3) type and one case of the adult (CLN4) type. The bulk of the series was represented by 26 cases of the late infantile (CLN2) type and by 27 cases of the early juvenile (CLN6) type (also called non-Finnish variant late infantile, or Lake-Cavanagh). Besides the infantile form, microcephaly was a relatively frequent finding (nine cases) in the late infantile and early juvenile NCLs. In more than half of the late infantile and early juvenile cases there was a significant reduction of the nerve conduction velocity. The early juvenile CLN6 type was found to have a relatively high incidence in the Romany population (12 cases in nine families). Incidence of NCL in the Czech republic is estimated to be 1.3:100,000.

Adolescent↗
PubMed1997

Complete spontaneous remission in a patient with metastatic non-small-cell lung cancer. Case report, review of the literature, and discussion of possible biological pathways involved.

Spontaneous remission of cancer (SR) is defined as a complete or partial, temporary or permanent disappearance of all or at least some relevant parameters of a soundly diagnosed malignant disease without any medical treatment or with treatment that is considered inadequate to produce the resulting regression. We report the case of a 61-year-old man who presented with extensive metatastic disease five months after pneumonectomy for poorly differentiated large cell and polymorphic lung cancer. A vast metastatic tumour mass of the abdominal wall was confirmed histolologically and there was clinical and radiographic evidence of liver and lung metastases. Eight months later, the patient was operated on for a hernia, which had developed in the inguinal biopsy scar and the surgeon confirmed complete clinical SR of the abdominal wall metastases. Again five months later there was no longer any radiologic evidence of liver and lung metastases. Complete remission has persisted more than five years. Histology of the primary and of the abdominal metastases were reviewed by several independent pathologists. SR is an extremly rare event in lung cancer. This is the first documented case of clinically evident visceral metastases of a bronchiogenic adenocarcinoma developing after complete resection of the primary and then showing complete SR. The epidemiology of SR is reviewed and possible mechanisms involved in SR are discussed.

Apoptosis↗
PubMed1997

Acute work injuries among electric utility meter readers.

This report provides estimates of incidence rates for acute work injuries for a well defined cohort of electric utility meter readers. Specifically, person-time rates by sex, age, and job experience are evaluated by part of body injured and type of injury. Meter readers experienced 731 acute lost time [11.1 per 100 person-work years; 95% confidence interval (CI) = 10.3-11.9] and 4,401 acute non-lost time (66.5 per 100 person-work years; 95% CI = 64.6-68.5) work injuries over the study period, 1980-1992. Women had nearly twice the lost time injury rate as men (17.5 vs 9.6 per 100 person-work years). There is an inverse relation between job experience and both lost time and non-lost time injuries. Although these data are limited to the electric utility industry, they may be relevant to occupations with similar tasks and environments, including residential gas and water supply industry meter readers and postal carriers.

Absenteeism↗
PubMed1996

The tRNATyr multigene family of Triticum aestivum: genome organization, sequence analyses and maturation of intron-containing pre-tRNAs in wheat germ extract.

Southern analysis of Triticum DNA has revealed that nuclear tRNATyr genes are dispersed at a minimum of 16 loci in the genome. We have isolated six independent tRNATyr genes from a Triticum aestivum library in addition to three known members of the Triticum tRNATyr family. Four of the sequenced tRNATyr genes code for Triticum tRNA Tyr and two code for tRNA2Tyr. Three genes encode tRNAsTyr which carry one or two nucleotide substitutions as compared to the conventional genes. The nine Triticum tRNATyr genes possess highly conserved intron sequences ranging in size from 12 to 14 nucleotides. A common secondary intron structure with the 5' and 3' splice site loops separated by five base pairs can be formed by all pre-tRNAs Tyr which are efficiently spliced in the homologous wheat germ extract.

Base Sequence↗
PubMed1996

Promoter region and alternatively spliced exons of the rat mu-opioid receptor gene.

The actions of exogenous and endogenous opioids are mediated by at least three different opioid receptors, called mu, kappa, and delta. Recently, we have detected a new variant of the rat mu-opioid receptor, which we termed rMOR1B and which differs from rMOR1 (now also called rMOR1A) in the amino acid sequence at the C-terminus. Both isoforms were proposed to be splicing variants of the same gene. To elucidate the molecular mechanism leading to the formation of the new variant, the exon/intron structure of the rat mu-opioid receptor gene in the respective area has been determined by analyzing a genomic P1 phage clone. In addition, we have investigated the putative promoter region of this gene. The present study revealed that rMOR1B is generated by an alternative splicing event whereby a previously unknown exon will be placed behind exon 3 to form rMOR1B mRNA, which is separated from the latter by an intron. Therefore, this new exon has to be called exon 4, whereas the former exon 4, which encodes the C-terminus of MOR1A, now becomes exon 5. Examination of the putative rat promoter region revealed a high degree of nucleotide sequence homology to the mouse gene. Using an RNase protection approach, one single transcription initiation site could be located at 230 bp upstream of the translation start. This is similar to the situation in the mouse, where four major transcription start sites were reported to lie close together around 270 bp upstream of the protein coding region.

Alternative Splicing↗
PubMed1996

[Results of reproduction and health research, the Czech Republic 1993: Part 1].

This article "deals with two basic spheres: natality (abortion rate) and family planning. Natality was evaluated by current indicators such as specific female birth rate, by age, aggregate fertility, and/or median age at birth of the first child." Women were also asked about contraceptive use, knowledge of contraceptive methods, and reasons for use or nonuse. (SUMMARY IN ENG)

Abortion, Induced↗
PubMed1995

The sigma factor sigma s affects antibiotic production and biological control activity of Pseudomonas fluorescens Pf-5.

Pseudomonas fluorescens Pf-5, a rhizosphere-inhabiting bacterium that suppresses several soilborne pathogens of plants, produces the antibiotics pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol. A gene necessary for pyrrolnitrin production by Pf-5 was identified as rpoS, which encodes the stationary-phase sigma factor sigma s. Several pleiotropic effects of an rpoS mutation in Escherichia coli also were observed in an RpoS- mutant of Pf-5. These included sensitivities of stationary-phase cells to stresses imposed by hydrogen peroxide or high salt concentration. A plasmid containing the cloned wild-type rpoS gene restored pyrrolnitrin production and stress tolerance to the RpoS- mutant of Pf-5. The RpoS- mutant overproduced pyoluteorin and 2,4-diacetyl-phloroglucinol, two antibiotics that inhibit growth of the phytopathogenic fungus Pythium ultimum, and was superior to the wild type in suppression of seedling damping-off of cucumber caused by Pythium ultimum. When inoculated onto cucumber seed at high cell densities, the RpoS- mutant did not survive as well as the wild-type strain on surfaces of developing seedlings. Other stationary-phase-specific phenotypes of Pf-5, such as the production of cyanide and extracellular protease(s) were expressed by the RpoS- mutant, suggesting that sigma s is only one of the sigma factors required for the transcription of genes in stationary-phase cells of P. fluorescens. These results indicate that a sigma factor encoded by rpoS influences antibiotic production, biological control activity, and survival of P. fluorescens on plant surfaces.

Amino Acid Sequence↗