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Biomedical subjects

V Steiner

Publications and source records attributed to V Steiner.

At least 19 recordsLinked to original sources
PubMed2005

Radon exhalation of cementitious materials made with coal fly ash: Part 1--scientific background and testing of the cement and fly ash emanation.

Increased interest in measuring radionuclides and radon concentrations in fly ash, cement and other components of building products is due to the concern of health hazards of naturally occurring radioactive materials (NORM). The current work focuses on studying the influence of fly ash (FA) on radon-exhalation rate (radon flux) from cementitious materials. The tests were carried out on cement paste specimens with different FA contents. The first part of the paper presents the scientific background and describes the experiments, which we designed for testing the radon emanation of the raw materials used in the preparation of the cement-FA pastes. It is found that despite the higher (226)Ra content in FA (more than 3 times, compared with Portland cement) the radon emanation is significantly lower in FA (7.65% for cement vs. 0.52% only for FA).

Air Pollutants, Radioactive↗
PubMed2005

Radon exhalation of cementitious materials made with coal fly ash: Part 2--testing hardened cement-fly ash pastes.

Increased interest in measuring radionuclides and radon concentrations in fly ash (FA), cement and other components of building products is due to the concern about health hazards of naturally occurring radioactive materials (NORM). The paper focuses on studying the influence of FA on radon exhalation rate (radon flux) from cementitious materials. In the previous part of the paper the state of the art was presented, and the experiments for testing raw materials, Portland cement and coal fly ash, were described. Since the cement and FA have the most critical role in the radon release process relative to other concrete constituents (sand and gravel), and their contribution is dominant in the overall radium content of concrete, tests were carried out on cement paste specimens with different FA contents, 0-60% by weight of the binder (cement+FA). It is found that the dosage of FA in cement paste has a limited influence on radon exhalation rate, if the hardened material is relatively dense. The radon flux of cement-FA pastes is lower than that of pure cement paste: it is about approximately 3 mBq m(-2) s(-1) for cement-FA pastes with FA content as high as 960 kg m(-3).

Air Pollutants, Radioactive↗
PubMed2004

Observation of a narrow charm-strange meson D(+)(sJ)(2632)-->D(+)(s)eta and D(0)K(+).

We report the first observation of a charm-strange meson D(+)(sJ)(2632) at a mass of 2632.5+/-1.7 MeV/c(2) in data from SELEX, the charm hadro-production experiment E781 at Fermilab. This state is seen in two decay modes, D(+)(s)eta and D0K+. In the D(+)(s)eta decay mode we observe a peak with 101 events over a combinatoric background of 54.9 events at a mass of 2635.4+/-3.3 MeV/c(2). There is a corresponding peak of 21 events over a background of 6.9 at 2631.5+/-2.0 MeV/c(2) in the decay mode D0K+. The decay width of this state is <17 MeV/c(2) at 90% confidence level. The relative branching ratio Gamma(D0K+)/Gamma(D(+)(s)eta) is 0.14+/-0.06. The mechanism that keeps this state narrow is unclear. Its decay pattern is also unusual, being dominated by the D(+)(s)eta decay mode.

Journal Article↗
PubMed2002

First observation of the doubly charmed baryon Xi(+)(cc).

We observe a signal for the doubly charmed baryon Xi(+)(cc) in the charged decay mode Xi(+)(cc)-->Lambda(+)(c)K-pi(+) in data from SELEX, the charm hadroproduction experiment at Fermilab. We observe an excess of 15.9 events over an expected background of 6.1+/-0.5 events, a statistical significance of 6.3sigma. The observed mass of this state is 3519+/-1 MeV/c(2). The Gaussian mass width of this state is 3 MeV/c(2), consistent with resolution; its lifetime is less than 33 fs at 90% confidence.

Journal Article↗
PubMed2001

Precision measurements of the lambda(+)(c) and D0 lifetimes.

We report new precision measurements of the lifetimes of the Lambda(+)(c) and D0 from SELEX, the charm hadroproduction experiment at Fermilab. Based upon 1630 Lambda(+)(c) and 10 210 D0 decays we observe lifetimes of tau[Lambda(+)(c)] = 198.1+/-7.0+/-5.6 fs and tau[D0] = 407.9+/-6.0+/-4.3 fs.

Journal Article↗
PubMed2001

Sexual dimorphism in body composition, weight status and growth in prepubertal school chiildren from rural areas of eastern Austria.

Sexual dimorphism in stature, weight status and body composition were analyzed in a sample of 398 prepubertal children (213 girls, 185 boys) ageing between 7 and 10. Furthermore the prevalence of overweight was tested. Body composition parameters were determined using TBF 105 Body composition analyzer according to BIA-method. Highly significant sex differences in body composition were observed (p < 0.001). In contrast, stature, weight and BMI showed no significant differences between the two sexes. Nevertheless, a significant higher portion (p < 0.05) of girls (29%) corresponded to the definition overweight according to ASNS (Austrian Survey of Nutritional Status), while only 20% of the boys felt into the category overweight. The results of the present study showed not only significant sex differences in body composition, especially in fat mass, long before puberty onset, but also a significantly higher prevalence of overweight among prepubertal girls in comparison to prepubertal boys.

Adipose Tissue↗
PubMed2000

Caspase-induced inactivation of the anti-apoptotic TRAF1 during Fas ligand-mediated apoptosis.

The activation of the transcription factor NF-kappaB often results in protection against apoptosis. In particular, pro-apoptotic tumor necrosis factor (TNF) signals are blocked by proteins that are induced by NF-kappaB such as TNFR-associated factor 1 (TRAF1). Here we show that TRAF1 is cleaved after Asp-163 when cells are induced to undergo apoptosis by Fas ligand (FasL). The C-terminal cleavage product blocks the induction of NF-kappaB by TNF and therefore functions as a dominant negative (DN) form of TRAF1. Our results suggest that the generation of DN-TRAF1 is part of a pro-apoptotic amplification system to assure rapid cell death.

Apoptosis↗
PubMed1999

BAFF, a novel ligand of the tumor necrosis factor family, stimulates B cell growth.

Members of the tumor necrosis factor (TNF) family induce pleiotropic biological responses, including cell growth, differentiation, and even death. Here we describe a novel member of the TNF family, designated BAFF (for B cell activating factor belonging to the TNF family), which is expressed by T cells and dendritic cells. Human BAFF was mapped to chromosome 13q32-34. Membrane-bound BAFF was processed and secreted through the action of a protease whose specificity matches that of the furin family of proprotein convertases. The expression of BAFF receptor appeared to be restricted to B cells. Both membrane-bound and soluble BAFF induced proliferation of anti-immunoglobulin M-stimulated peripheral blood B lymphocytes. Moreover, increased amounts of immunoglobulins were found in supernatants of germinal center-like B cells costimulated with BAFF. These results suggest that BAFF plays an important role as costimulator of B cell proliferation and function.

Amino Acid Sequence↗
PubMed1999

Equine herpesvirus-2 E10 gene product, but not its cellular homologue, activates NF-kappaB transcription factor and c-Jun N-terminal kinase.

We have previously reported on the death effector domain containing E8 gene product from equine herpesvirus-2, designated FLICE inhibitory protein (v-FLIP), and on its cellular homologue, c-FLIP, which inhibit the activation of caspase-8 by death receptors. Here we report on the structure and function of the E10 gene product of equine herpesvirus-2, designated v-CARMEN, and on its cellular homologue, c-CARMEN, which contain a caspase-recruiting domain (CARD) motif. c-CARMEN is highly homologous to the viral protein in its N-terminal CARD motif but differs in its C-terminal extension. v-CARMEN and c-CARMEN interact directly in a CARD-dependent manner yet reveal different binding specificities toward members of the tumor necrosis factor receptor-associated factor (TRAF) family. v-CARMEN binds to TRAF6 and weakly to TRAF3 and, upon overexpression, potently induces the c-Jun N-terminal kinase (JNK), p38, and nuclear factor (NF)-kappaB transcriptional pathways. c-CARMEN or truncated versions thereof do not appear to induce JNK and NF-kappaB activation by themselves, nor do they affect the JNK and NF-kappaB activating potential of v-CARMEN. Thus, in contrast to the cellular homologue, v-CARMEN may have additional properties in its unique C terminus that allow for an autonomous activator effect on NF-kappaB and JNK. Through activation of NF-kappaB, v-CARMEN may regulate the expression of the cellular and viral genes important for viral replication.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Family adaptation to institutionalised mentally retarded patients. A preliminary report on an Italian population.

Family interactive patterns were investigated in the relatives of 20 mentally retarded patients institutionalised in two centres in Northern Italy. Expressed emotion (EE) was used as evaluation instrument. The results show a surprisingly high rate (45%) of high EE, even in relatives of patients who did not live inside the family. High EE was positively correlated to the presence of behavioral disorders in the patients, as already shown for children with conduct disorders. Treatment implications are discussed; there is an opportunity for the implementation of a family psychoeducational approach, aimed both at managing the behavioural consequences of the disorder and at enhancing rehabilitation programmes.

Adaptation, Psychological↗
PubMed1997

Inhibition of death receptor signals by cellular FLIP.

The widely expressed protein Fas is a member of the tumour necrosis factor receptor family which can trigger apoptosis. However, Fas surface expression does not necessarily render cells susceptible to Fas ligand-induced death signals, indicating that inhibitors of the apoptosis-signalling pathway must exist. Here we report the characterization of an inhibitor of apoptosis, designated FLIP (for FLICE-inhibitory protein), which is predominantly expressed in muscle and lymphoid tissues. The short form, FLIPs, contains two death effector domains and is structurally related to the viral FLIP inhibitors of apoptosis, whereas the long form, FLIP(L), contains in addition a caspase-like domain in which the active-centre cysteine residue is substituted by a tyrosine residue. FLIPs and FLIP(L) interact with the adaptor protein FADD and the protease FLICE, and potently inhibit apoptosis induced by all known human death receptors. FLIP(L) is expressed during the early stage of T-cell activation, but disappears when T cells become susceptible to Fas ligand-mediated apoptosis. High levels of FLIP(L) protein are also detectable in melanoma cell lines and malignant melanoma tumours. Thus FLIP may be implicated in tissue homeostasis as an important regulator of apoptosis.

Adaptor Proteins, Signal Transducing↗
PubMed1997

TRAMP, a novel apoptosis-mediating receptor with sequence homology to tumor necrosis factor receptor 1 and Fas(Apo-1/CD95).

A novel member of the tumor necrosis factor (TNF) receptor family, designated TRAMP, has been identified. The structural organization of the 393 amino acid long human TRAMP is most homologous to TNF receptor 1. TRAMP is abundantly expressed on thymocytes and lymphocytes. Its extracellular domain is composed of four cysteine-rich domains, and the cytoplasmic region contains a death domain known to signal apoptosis. Overexpression of TRAMP leads to two major responses, NF-kappaB activation and apoptosis. TRAMP-induced cell death is inhibited by an inhibitor of ICE-like proteases, but not by Bcl-2. In addition, TRAMP does not appear to interact with any of the known apoptosis-inducing ligands of the TNF family.

Adaptor Proteins, Signal Transducing↗
PubMed1994

Interocular transfer of expansion, rotation, and translation motion aftereffects.

The motion aftereffect demonstrates the existence of direction-selective mechanisms in the visual system. However, direction-selective cells exist within many visual areas, including V1 and MT/V5. Can motion aftereffects be generated within each of these areas? In visual cortical areas beyond V1 almost all cells are binocular, whereas a smaller percentage are binocular in V1. The degree of binocularity can be revealed psychophysically by assessing interocular transfer. Interocular transfer of motion aftereffects generated from expanding rotating, and translating dynamic random-dot patterns were therefore compared, since these stimuli should activate cells in higher visual areas selectively. Partial interocular transfer was found that was greater for expansion and rotation than for translation. The results support the involvement of higher visual areas in motion aftereffects to complex animation sequences.

Female↗
PubMed1993

[Mental retardation and family environment: role of emotional factors].

The authors present data from an experimental study conducted on 20 institutionalized mentally handicapped adult patients. Relevant family variables were investigated by means of the Expressed Emotion (EE) scales, then compared with similar variables obtained in a matched sample of 20 schizophrenic patients and their families. Results show, in relatives of mentally handicapped patients, a higher rate of Warmth than in relatives of schizophrenics (p = 0.009), while other EE scales appear to reach similar values in both groups. Within the mentally handicapped family group, a higher rate of Emotional Over-involvement (p = 0.046) is shown by relatives of patients treated with neuroleptic drugs. The presence of high Warmth and Emotional Over-involvement, together with low Criticism and Hostility, may be interpreted as adaptation by the families to an organic disease with very early onset, clearer ad less rejecting than schizophrenia.

Adolescent↗
PubMed1992

Primary structure and function of novel O-glycosylated hirudins from the leech Hirudinaria manillensis.

Hirudin from the leech Hirudo medicinalis is a most powerful anticoagulant, and many isoforms have been described. In the present work, the primary structure of two hirudins from the leech Hirudinaria manillensis has been elucidated. The antithrombotic activity is similar to that of H. medicinalis hirudins although the sequence identity is below 60%. Surprisingly, the hirudins were found to be glycosylated at one site. Sugar analysis after methanolysis yielded fucose, galactose, and N-acetylgalactosamine. These results combined with data from matrix-assisted laser desorption ionization mass spectrometry, plasma desorption mass spectrometry, capillary zone electrophoresis, and lectin-binding tests indicate that the sequence is Fuc-Gal beta 1-3GalNAc-(O-threonine). This structure shows an interesting similarity to human blood group H determinants.

Amino Acid Sequence↗
PubMed1991

Retention behaviour of a template-assembled synthetic protein and its amphiphilic building blocks on reversed-phase columns.

The retention behaviour of a six-helix bundle template-assembled synthetic protein (TASP) molecule and its amphiphilic building blocks was investigated. The TASP consists of a circular template, cyclo(1-12)[KG]6, and six identical potentially alpha-helical peptides of the sequence KLALKLALKALKLALKLA. As an alpha-helix, this peptide is amphiliphilic along the axis of its helix. Based on this sequence, the retention times of a set of acetylated peptides containing from seven to twenty amino acids on a Nucleosil C18 column were compared with another set of peptides with the same amino acid composition but a non-amphiphilic structure. Peptide elution was effected with linear trifluoroacetic acid (TFA)-water to TFA-acetonitrile gradients. The difference in retention times increased with peptide length; the 9-mers eluted at the same time, but there was a difference of 3.5 min for the 13-mers and 22.3 min for the 20-mer, indicating the induction of secondary structure on binding to the stationary phase. The same pair of 20-mers on Vydac C18, C4 and biphenyl columns gave differences in retention times of 23.2, 16.7 and 12.3 min respectively. The TASP molecule was irreversibly adsorbed to C18 stationary phases, whereas it was eluted from C4 and biphenyl columns as a single sharp peak. Several side-products resulting from the synthesis of the TASP molecule were identified by matrix-assisted laser desorption ionization mass spectroscopy. A comparison of the retention times of these side-products and the results of pre-column denaturation experiments indicated that the tertiary structure of the TASP molecule is maintained on binding to biphenyl and C4 columns.

Amino Acid Sequence↗