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O Schneider

Publications and source records attributed to O Schneider.

At least 19 recordsLinked to original sources
PubMed2004

Observation of the radiative decay D0-->phigamma.

We report the observation of the decay D0-->phigamma with a statistical significance of 5.4sigma in 78.1 fb(-1) of data collected by the Belle experiment at the KEKB e+e- collider. This is the first observation of a flavor-changing radiative decay of a charmed meson. The Cabibbo- and color-suppressed decays D0-->phipi(0), phieta are also observed for the first time. We measure branching fractions B(D0-->phigamma)=[2.60(+0.70)(-0.61)(stat)+0.15-0.17(syst)] x 10(-5), B(D0-->phipi(0))=[8.01+/-0.26(stat)+/-0.47(syst)] x 10(-4), and B(D0-->phieta)=[1.48+/-0.47(stat)+/-0.09(syst)] x 10(-4).

Journal Article↗
PubMed2003

Cerec veneers--practical procedure and case presentation.

The Cerec method offers experienced users the possibility of accomplishing veneers chairside which are capable of meeting the highest functional and esthetic requirements. "Esthetic shaping" directly on the patient requires a good eye for color and form, and this requires training. The present report outlines the clinical procedure and presents three clinical cases step by step, specifically discussing the external staining technique with Pro-CAD blocks.

Adolescent↗
PubMed2001

A six-degree-of-freedom passive arm with dynamic constraints (PADyC) for cardiac surgery application: preliminary experiments.

The purpose of Computer-Assisted Surgery (CAS) is to help physicians and surgeons plan and execute optimal strategies from multimodal image data. The execution of such planned strategies may be assisted by guidance systems. Some of these systems, called synergistic systems, are based on the cooperation of a robotic device with a human operator. We have developed such a synergistic device: PADyC (Passive Arm with Dynamic Constraints). The basic principle of PADyC is to have a manually actuated arm that dynamically constrains the authorized motions of the surgical tool held by the human operator during a planned task. Dynamic constraints are computed from the task definition, and are implemented by a patented mechanical system. In this paper, we first introduce synergistic systems and then focus on modeling and algorithmic issues related to the dynamic constraints. Finally, we describe a 6-degree-of-freedom prototype robot designed for a clinical application (cardiac surgery) and report on preliminary experiments to date. The experimental results are then discussed, and future work is proposed.

Algorithms↗
PubMed2001

Differential display analysis of hemocytes from schistosome-resistant and schistosome-susceptible intermediate hosts.

Hemocytes from schistosome-resistant and schistosome-susceptible Biomphalaria glabrata differ fundamentally in their behavior towards an invading parasite. When the schistosome infects a resistant snail host it is quickly surrounded by hemocytes, encapsulated and destroyed. Hemocytes from susceptible hosts fail to kill the parasite. To detect the differences between these two host phenotypes, we used differential-display reverse-transcription PCR (DDRT-PCR), based on RNA extracted from isolated hemocytes. A number of differentially expressed fragments from resistant and susceptible snails were detected by DDRT-PCR and confirmed using single-strand conformation polymorphism. These methods proved to be sensitive enough to allow comparison and verification of differential gene expression in our system, where only small numbers of cells are available. The most interesting phenotype-specific fragments detected so far show sequence homologies to an adhesion molecule, defensin, serine/ threonine kinases, peroxidases and glycosidases.

Animals↗
PubMed2000

Comparative analysis of follistatin-, activin beta A- and activin beta B-mRNA steady-state levels in diverse porcine tissues by multiplex S1 nuclease analysis.

OBJECTIVE: The relation of activins (dimers of the beta-subunits of inhibin) and follistatin (FS) (their binding protein) affect the growth and differentiation of many cell types. Activin- and FS-mRNAs show a widespread co-expression throughout the organism, indicating an essential role for the FS/activin system in diverse physiological processes. The present study was performed to investigate FS-, activin betaA-, and activin beta B-mRNA expression in porcine tissues and to compare the relative mRNA tissue distribution by a newly developed multiplex S1 nuclease protection assay. METHODS: Twenty micrograms total RNA from different porcine tissues were subjected to multiplex S1 analysis. Specific mRNA expression was determined by measurements of optical densities on autoradiographs. RESULTS: Activin beta A-mRNA expression was abundant in the ovary, adrenal gland, fat, vein, artery and uterus, activin beta B-mRNA was highly expressed in the ovary, pituitary, uterus, placenta, aorta and cerebellum. FS-mRNA showed a widespread expression with high levels in ovary, uterus, cerebellum, placenta and fat. The comparison of relative activin beta A-, activin beta B- and FS-mRNA expression within a certain tissue showed a predominance of activin beta A-mRNA in the adrenal gland, fat, artery, spinal cord, cerebrum and colon and of activin beta B-m RNA in pituitary, testis and placenta, while FS-mRNA levels exceeded those of activin subunits in epididymis, liver, lymphoid tissue, muscle, intestine, cerebellum, ovary and uterus. CONCLUSIONS: The presented data provide an overview of FS-, activin beta A-, and activin beta B-mRNA steady state levels in porcine tissues.

Activins↗
PubMed2000

Follistatin (FS) in human cerebrospinal fluid and regulation of FS expression in a mouse model of meningitis.

OBJECTIVE: Follistatin (FS) is the specific binding protein of activin and expression of both factors is regulated by inflammatory agents. Therefore, FS concentrations were determined in cerebrospinal fluid (CSF) of patients with bacterial and viral meningitis or multiple sclerosis (MS), as well as in the CSF of patients without meningial inflammation or autoimmune diseases. Furthermore, a mouse pneumococcal meningitis model was used to localise the cellular sources of FS in brains of normal and meningitic mice. METHODS: FS concentrations in CSF were determined by ELISA; FS in mice was localised by in situ hybridisation and immunohistochemistry. RESULTS: FS concentrations were > or =0.4 microg/l in 22 of 66 CSF samples of meningitis patients versus 2 of 27 CSF samples from patients with multiple sclerosis (P<0.05) and 2 of 41 CSF specimen from patients without neuroinflammatory diseases (P<0.01). In the CSF of patients with meningitis, the concentration of FS was correlated with total protein (P<0.005) and lactate concentrations (P<0.05), but not with leukocyte counts, interval between onset of disease and CSF analysis, or clinical outcome. The CSF-to-serum ratios of FS and albumin also correlated significantly (P<0.0005). In some patients with meningitis the CSF-to-serum ratios suggested that the elevated FS in CSF did not originate from serum alone. FS was localised in mice brains to neurones of the hippocampus, dentate gyrus, neocortex, and to the choroid plexus. Analyses of brains and other organs from uninfected and infected animals sacrificed 6-36 h after infection did not reveal any obvious differences in the distribution and intensity of FS mRNA and protein expression. CONCLUSIONS: The concentration of FS in humans is elevated during meningitis. In some patients the increase is caused by a release of FS from brain into CSF. Data from the mouse meningitis model suggest that increased CSF concentrations of FS in meningitis appear not to be accompanied by an elevated number of cells containing FS mRNA or protein in the brain.

Animals↗
PubMed1999

Clinical outcome in pneumococcal meningitis correlates with CSF lipoteichoic acid concentrations.

Lipoteichoic and teichoic acids are components of the cell wall of Streptococcus pneumoniae. A recently developed enzyme immunoassay was used in patients with pneumococcal meningitis to investigate lipoteichoic and teichoic acid concentrations in CSF at the first lumbar puncture in relation to the clinical outcome determined by the Glasgow Outcome Scale. Lipoteichoic and teichoic acid concentrations in CSF were significantly associated with neurologic sequelae and mortality in S. pneumoniae meningitis.

Adolescent↗
PubMed1999

Rifampin reduces early mortality in experimental Streptococcus pneumoniae meningitis.

Compared with beta-lactam antibiotics, rifampin releases smaller quantities of proinflammatory cell wall products from Streptococcus pneumoniae in vitro. Mice infected intracerebrally with S. pneumoniae were treated subcutaneously with 2-mg doses of rifampin or ceftriaxone (n=43 each) every 12 h for 3 days and then observed for another 3 days. Rifampin reduced overall mortality from 49% to 26% (P=.04). Kaplan-Meyer analysis revealed a substantial reduction of mortality during the first 24 h in mice receiving rifampin (difference in survival time: P=.007). Eight h after receiving a single 2-mg dose of rifampin or ceftriaxone, rifampin-treated mice had lower serum and cerebrospinal fluid concentrations of lipoteichoic and teichoic acids than did ceftriaxone-treated mice (median serum level: <0.5 vs. 27.0 ng/mL, P=.02; median cerebrospinal fluid level of pooled specimens: 97.5 vs. 206.0 ng/mL). Thus, the use of rifampin appears promising for reducing the release of proinflammatory bacterial components and decreasing early mortality in bacterial meningitis.

Animals↗
PubMed1999

To what extent are biomonitoring data available in chemical risk assessment?

1. Chemical risk assessment integrates the identification of hazards and the human exposure levels which can be established from external and/or internal exposure data. 2. The availability of biomonitoring and metabolism animal data, the skin penetration ability, and the existence of atmospheric threshold limit values were examined for twelve substances of the European first list of priority existing substances. This investigation was focused on workplace exposures and on urinary biomarkers of exposure. Appropriate biomonitoring data appeared to be available for two substances: styrene and trichloroethylene. Some biomonitoring research has been conducted on acrylonitrile, buta-1,3-diene, cyclohexane, 1,4-dichlorobenzene, hydrogen fluoride, 2-(2-methoxyethoxy)ethanol, however additional studies could be usefully carried out. No biomonitoring data are available for alkanes, C10-13, chloro; benzene, C10-13-alkyl derivatives; bis(pentabromophenyl)ether; diphenylether, octabromo-derivative. 3. It was concluded that in some cases, biomonitoring data are either lacking or scarce. This is rather surprising since the selection of the substances of the priority list was based on high tonnage, widespread use, extent of human exposure, and toxicological concern. The development of biomonitoring information could be helpful in assessing individual or population chemical exposure whatever the source and route, and would result in both more realistic and more accurate risk assessments.

Acrylonitrile↗
PubMed1998

Laminar and arch fractures with dural tear and nerve root entrapment in patients operated upon for thoracic and lumbar spine injuries.

OBJECTIVE: To determine the neurological outcome in patients with laminar fractures associated with dural tears and nerve root entrapment, operated upon for thoracic and lumbar spine injuries. PATIENT POPULATION: Out of 103 patients operated upon consecutively for thoracic and lumbar spine injuries during the period 1990 to 1994 inclusive, 24 (23.3%) patients had laminar fractures out of whom 3 (2.9%) had an associated dural tear and an other 17 (16.5% or 70.8% of the total patients with laminar fractures) had an associated dural tear and nerve root entrapment. RESULTS: Twelve (70.5%) patients had injury at the thoraculumbar junction, 13 (76.5%) had Magerl's type A3 or above, 10 (58.8%) had a kyphotic angle deformity greater than 5 degrees. Seven (41.1%) had their spinal canal's sagittal diameter reduced by at least 50% and two had dislocations. Nine (52.9%) had initial neurological deficits. Four (50%) out of 8 patients with no initial neurological deficits (Frankel E) worsened to Frankel D. However, one patient among the 3 with initial Frankel A improved to Frankel C while both patients with initial Frankel C usefully improved to final Frankel grades D and E respectively. Two of the four patients with initial Frankel D improved to Frankel E, the other 2 remaining unchanged. All in all five patients neurological status improved, 4 worsened and 8 remained unchanged after neurosurgical treatment. CONCLUSIONS: Vertical laminar fractures with dural tears and nerve root entrapment represent a special group of thoracic and lumbar spine injuries that carry a poor prognosis. However, special operative precautions lead to significant improvement in some of them although a majority remain unchanged or even worsened.

Adult↗
PubMed1998

Radiological investigations and intra-operative evoked potentials for the diagnosis of nerve root avulsion: evaluation of both modalities by intradural root inspection.

Fourteen patients with traumatic brachial plexus injuries underwent intradural inspection of cervical nerve roots to evaluate radiological and intra-operative electrophysiological findings concerning cervical nerve root avulsion from the spinal cord. Four neurosurgeons of our department assessed independently from each other both myelography and CT-myelography concerning intradural nerve root lesions. Each neurosurgeon assessed a total of 26 cervical nerve roots. Two investigators assessed 6/26 and 2 investigators 7/26 nerve roots falsely concerning ventral or/and dorsal root lesions compared with the findings on intradural inspection (23% and 27% false findings). There was a considerable variance concerning the assessibility and findings among the 4 neurosurgeons. Reconstructive surgery was performed after a mean interval of 6.5 months following trauma and 2 weeks following intradural inspection. After exposure of the brachial plexus and the cervical nerve roots in question via a ventral approach, 13 cervical nerve roots were stimulated electrically close to the neuroforamen and cortical evoked potentials (root-SEPs) were recorded from the contralateral postcentral region. All 5 roots with SEPs were intact (no root lesion) and all 8 roots without SEPs showed interrupted (ventral or/and dorsal) rootlets on intradural inspection. Our results demonstrate that false radiological findings concerning root lesions are possible. Intra-operative root-SEPs seem to be a useful aid for evaluation of cervical nerve root lesions. However, more electrophysiological data are necessary to ascertain, if this modality is able to replace intradural inspection in unclear radiological cases in the future.

Adolescent↗
PubMed1998

Moxifloxacin in the therapy of experimental pneumococcal meningitis.

The activity of moxifloxacin (BAY 12-8039) against a Streptococcus pneumoniae type 3 strain (MIC and minimum bactericidal concentration [MBC] of moxifloxacin, 0.06 and 0.25 microgram/ml, respectively; MIC and MBC of ceftriaxone, 0.03 and 0.06 microgram/ml, respectively) was determined in vitro and in a rabbit model of meningitis. Despite comparable bactericidal activity, 10 micrograms of moxifloxacin per ml released lipoteichoic and teichoic acids less rapidly than 10 micrograms of ceftriaxone per ml in vitro. Against experimental meningitis, 10 mg of moxifloxacin per kg of body weight per ml reduced the bacterial titers in cerebrospinal fluid (CSF) almost as rapidly as ceftriaxone did (mean +/- standard deviation, -0.32 +/- 0.14 versus -0.39 +/- 0.11 delta log CFU/ml/h). The activity of moxifloxacin could be described by a sigmoid dose-response curve with a maximum effect of -0.33 delta log CFU/ml/h and with a dosage of 1.4 mg/kg/h producing a half-maximal effect. Maximum tumor necrosis factor activity in CSF was observed later with moxifloxacin than with ceftriaxone (5 versus 2 h after the initiation of treatment). At 10 mg/kg/h, the concentrations of moxifloxacin in CSF were 3.8 +/- 1.2 micrograms/ml. Adjunctive treatment with dexamethasone at 1 mg/kg prior to the initiation of antibiotic treatment only marginally reduced the concentrations of moxifloxacin in CSF (3.3 +/- 0.6 micrograms/ml). In conclusion, moxifloxacin may qualify for use in the treatment of S. pneumoniae meningitis.

Animals↗
PubMed1996

Neurosurgical management of thoracic and lumbar vertebral osteomyelitis and discitis in adults: a review of 43 consecutive surgically treated patients.

We report 43 consecutive surgically treated patients with pyogenic (37 patients) and tuberculous (6 patients) osteomyelitis of the thoracic and lumbar spine encountered within an 8-year period, including 1 with late recurrence after 15 months. There were 24 men and 18 women, ranging in age from 21 to 83 years. Twenty-six patients were in poor general condition because of associated illnesses, especially diabetes mellitus. Disease occurred at the thoracic level in 19 patients and on the lumbar spine in 24. After diagnosis, five patients were merely treated by posterior decompression; three of them, however, required further surgery for recurrent infection, spinal instability, and secondary neurological impairment. They are included in the 40 patients who underwent combined posterior débridement and internal fixation with transpedicular screw-rod systems. Autologous interbody bone grafting was performed simultaneously in 18 patients and in a second stage operation in 21 patients. One of them (tuberculous) experienced early recurrence and required anterior fusion. In two patients, methylmethacrylate packing was used for spine reconstruction; one of them had a late recurrence. Of the 26 patients with preoperative marked or severe neurological deficit (Frankel Grades A, 2 patients; B, 1 patient; C, 17 patients; and D, 6 patients), 23 (88%) had significant improvement of one grade (15 patients) or more (8 patients). There were no permanent complications. However, intensive care treatment was necessary in 20 of the 26 patients in reduced general condition (mean age, 72 yr). Two patients required further surgery because of postoperative epidural hematoma and pedicle screw malpositioning. In conclusion, most patients with thoracic and lumbar osteomyelitis can be successfully treated by combined débridement and internal fixation using only a posterior approach. Autogenous interbody bone grafting can be simultaneously performed and allows early mobilization of the patient.

Adult↗
PubMed1996

Production of follistatin in porcine endothelial cells: differential regulation by bacterial compounds and the synthetic glucocorticoid RU 28362.

Follistatin (FS) is the specific binding protein of activin; it has a broad tissue distribution and is also found in serum. The ovary has the highest level of FS expression, but ovariectomy does not cause a permanent reduction in the serum FS level. Therefore, the source of FS in serum is still elusive. As a regulatable, nongonadal source of serum FS could influence ovarian and pituitary-derived hormone secretion and thus reproductive function, we searched for a source of extragonadal FS expression that might contribute to the FS protein level in serum. We found that endothelial cells from blood vessels express FS messenger RNA (mRNA) and protein; therefore, we studied the regulation of steady state levels of FS mRNA in porcine endothelial cells from aorta (AEC) and brain microvessels (BMVEC) in tissue culture. For detection of FS mRNA, a specific 32P-radiolabeled antisense probe and a S1-nuclease protection assay were used. FS steady state levels of AEC decreased with time in culture, i.e. postconfluent AEC had lower FS mRNA levels than confluent cultures, which, in turn, had lower FS mRNA levels than subconfluent cell cultures. FS mRNA levels in AEC were induced by increasing concentrations of FCS and stimulated by 30 micrograms/ml endothelial cell growth supplement. FS mRNA levels in AEC and BMVEC increased approximately 20-fold within 4 h during incubation of the cells with 100 nM phorbol 12-myristate, 13-acetate, whereas 0.5 nmol/ml forskolin tested in AEC for between 4-48 h had no significant effect. Furthermore, 0.1 microM ocadaic acid, an inhibitor of serine/threonine phosphatases 1 and 2A, caused a significant increase in FS mRNA levels. FS mRNA levels in AEC were not significantly affected by various concentrations of porcine FSH, epidermal growth factor, or retinoic acid for between 4-48 h. Treatment of the cells with 0.01-10 micrograms/ml bacterial lipopolysaccharides (LPS) caused a dose-dependent increase (up to 10-fold) in FS mRNA steady state level in AEC, whereas 1-1000 nM RU 28362, a synthetic glucocorticoid, inhibited FS mRNA steady state levels in a dose-dependent manner. The induction of FS mRNA with 1 microgram/ml LPS was completely blocked by 100 nM RU 28362, and the stimulatory effects of LPS were only visible after 4 h of treatment, not after 24 or 48 h. The same effects were observed with BMVEC. We, furthermore, analyzed FS protein secretion of AEC by Western blotting and demonstrated that FS proteins were secreted into the culture medium upon stimulation with LPS. None of these treatments had an obvious effect on the ratio of the two different forms of FS mRNA (FS 344:FS 317). Besides the expression of FS mRNA in AEC and BMVEC, FS mRNA is also expressed in uncultured plexus choroideus epithel and meninges, and FS protein is found in human cerebrospinal fluid. From this study it is concluded that 1) endothelial cells from different tissues produce FS mRNA; 2) the FS mRNA levels of AEC and BMVEC are subjected to regulation by FCS, endothelial cell growth supplement, bacterial LPS, and the glucocorticoid RU 28362; 3) phosphatases and the protein kinase C-dependent, but not the protein kinase A-dependent, pathway are involved in regulating the steady state levels of FS mRNA in AEC and BMVEC; and 4) endothelial cells produce and secrete FS protein and are thus a likely source of FS in serum.

Androstanols↗
PubMed1995

Cytotoxic and transforming effects of some iron-containing minerals in Syrian hamster embryo cells.

Four physicochemically characterized iron-containing minerals, one fibrous (a nemalite [brucite]) and three nonfibrous (a biotite [phyllosilicate], a magnetite (Fe3O4), and a goethite [FeOOH alpha]), were studied for cytotoxicity and morphological transformation of Syrian hamster embryo (SHE) cells. When colony-forming efficiency was used as a measure of cytotoxicity, it appeared that the nemalite was about 1.7-fold more cytotoxic than the biotite and magnetite. However, if the inhibitory effect on the cell growth was considered the nemalite appeared to be 8-fold more effective. The analysis of the cell cycle kinetics by flow cytometry revealed a time- and dose-dependent delay in the progression of cells through the cell cycle, with the accumulation of cells in S and G2-M phases, more particularly in the cultures treated with nemalite. While the goethite was neither cytotoxic nor transforming, the other three dusts were, in a dose-dependent manner, efficient in inducing morphological transformation of SHE cells. According to their transforming potency they ranged as follows: nemalite > biotite > magnetite. A 18-fold higher treatment concentration of magnetite than that of nemalite was necessary to induce the same transformation frequency. The iron chelator desferrioxamine abolished the transforming effect of nemalite. The results suggest that (i) the cytotoxicity and the transformation are induced by some divalent iron-containing minerals and that they are two distinct processes; (ii) there is a varying ability among these dusts to induce cell transformation; and (iii) the bioavailability of divalent iron leading to formation of reactive iron-oxygen species could mediate the transforming potency of a mineral. Physicochemical studies correlated to biological effects of many metallic mine dusts are the only approach for understanding their mechanisms of action and their role in occupational pathology.

Aluminum Silicates↗
PubMed1994

[Intraosseous lipoma of the calcaneus].

This report presents one case of rare benign intraosseus lipoma of the os calcis, which is analysed under the clinical, histopathologic and radiologic view. Not only the radiographic but also the computed tomographic findings has shown a typical picture of an intraosseous lipoma including a central calcification. In order to exclude a malignant transformation and as a prophylaxis of a pathological fracture the operative removal and bone graft transplantation is considered as therapy of choice.

Bone Neoplasms↗
PubMed1993

[Special aspects in diagnosis and treatment of open craniocerebral injuries including basilar skull fractures].

The possibility of CSF leakage means that open head injuries and skull base fractures are serious and sometimes dangerous. An operation should be considered in cases of open depressed skull fractures with or without space-occupying haematoma, compound fractures of the rhinobasis and orbita, dislocated fractures of the dorsal wall of the frontal sinus, CSF leakage for longer than 1 week, and posttraumatic intracranial infection. Operative and posttraumatic intracranial infection is also potentially dangerous. The operative approach depends on the type and localization of the fracture. The transsphenoidal and frontoorbital approaches are less traumatic, but offer only limited visibility. The transfrontal intradural approach offers by far the best view of the frontobasis and is therefore indicated in most cases.

Bone Plates↗