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Biomedical subjects

A Grossmann

Publications and source records attributed to A Grossmann.

At least 19 recordsLinked to original sources
PubMed2004

Sonographic discrimination of corticobasal degeneration vs progressive supranuclear palsy.

OBJECTIVE: To study the use of brain parenchyma sonography (BPS) in discriminating between patients with corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). METHODS: Thirteen patients with PSP and eight with CBD were studied with BPS according to a standardized protocol. RESULTS: Seven (88%) of the eight CBD patients showed marked hyperechogenicity of the substantia nigra (SN) but none of eleven PSP patients (Mann-Whitney U test, p < 0.001). This finding indicated CBD with a positive predictive value of 100%. Marked dilatation of the third ventricle (width > 10 mm) was found in 10 (83%) of 12 PSP patients, but in none of the CBD patients (p < 0.005). BPS measurements of ventricle widths closely matched MRI measurements (Pearson correlation, r = 0.90, p < 0.001). The presence of at least one of the BPS findings 1) marked SN hyperechogenicity and 2) third-ventricle width < 10 mm indicated CBD with a sensitivity of 100%, a specificity of 83%, and a positive predictive value of 80%. Other BPS findings such as echogenicity of lentiform and caudate nuclei and widths of the frontal horns did not discriminate between CBD and PSP. One PSP patient could not be assessed because of insufficient acoustic temporal bone windows. CONCLUSIONS: Substantia nigra hyperechogenicity, reported earlier as characteristic brain parenchyma sonography finding in idiopathic Parkinson disease, is also typical for corticobasal degeneration.

Aged↗
PubMed2004

Measurement of the negative muon anomalous magnetic moment to 0.7 ppm.

The anomalous magnetic moment of the negative muon has been measured to a precision of 0.7 ppm (ppm) at the Brookhaven Alternating Gradient Synchrotron. This result is based on data collected in 2001, and is over an order of magnitude more precise than the previous measurement for the negative muon. The result a(mu(-))=11 659 214(8)(3) x 10(-10) (0.7 ppm), where the first uncertainty is statistical and the second is systematic, is consistent with previous measurements of the anomaly for the positive and the negative muon. The average of the measurements of the muon anomaly is a(mu)(exp)=11 659 208(6) x 10(-10) (0.5 ppm).

Journal Article↗
PubMed2002

Measurement of the positive muon anomalous magnetic moment to 0.7 ppm.

A higher precision measurement of the anomalous g value, a(mu)=(g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron, based on data collected in the year 2000. The result a(mu(+))=11 659 204(7)(5)x10(-10) (0.7 ppm) is in good agreement with previous measurements and has an error about one-half that of the combined previous data. The present world average experimental value is a(mu)(expt)=11 659 203(8)x10(-10) (0.7 ppm).

Journal Article↗
PubMed2001

Bose-Einstein condensation in a surface microtrap.

Bose-Einstein condensation has been achieved in a magnetic surface microtrap with 4 x 10(5) (87)Rb atoms. The strongly anisotropic trapping potential is generated by a microstructure which consists of microfabricated linear copper conductor of widths ranging from 3 to 30 microm. After loading a high number of atoms from a pulsed thermal source directly into a magneto-optical trap the magnetically stored atoms are transferred into the microtrap by adiabatic transformation of the trapping potential. In the microtrap the atoms are cooled to condensation using forced rf-evaporation. The complete in vacuo trap design is compatible with ultrahigh vacuum below 2 x 10(-11) mbar.

Journal Article↗
PubMed2001

Precise measurement of the positive muon anomalous magnetic moment.

A precise measurement of the anomalous g value, a(mu) = (g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron. The result a(mu+) = 11 659 202(14) (6) x 10(-10) (1.3 ppm) is in good agreement with previous measurements and has an error one third that of the combined previous data. The current theoretical value from the standard model is a(mu)(SM) = 11 659 159.6(6.7) x 10(-10) (0.57 ppm) and a(mu)(exp) - a(mu)(SM) = 43(16) x 10(-10) in which a(mu)(exp) is the world average experimental value.

Journal Article↗
PubMed2001

Interleukin 20: discovery, receptor identification, and role in epidermal function.

A structural, profile-based algorithm was used to identify interleukin 20 (IL-20), a novel IL-10 homolog. Chromosomal localization of IL-20 led to the discovery of an IL-10 family cytokine cluster. Overexpression of IL-20 in transgenic (TG) mice causes neonatal lethality with skin abnormalities including aberrant epidermal differentiation. Recombinant IL-20 protein stimulates a signal transduction pathway through STAT3 in a keratinocyte cell line, demonstrating a direct action of this ligand. An IL-20 receptor was identified as a heterodimer of two orphan class II cytokine receptor subunits. Both receptor subunits are expressed in skin and are dramatically upregulated in psoriatic skin. Taken together, these results demonstrate a role in epidermal function and psoriasis for IL-20, a novel cytokine identified solely by bioinformatics analysis.

Animals↗
PubMed2001

Dysfunction of transcallosally mediated motor inhibition and callosal morphology in patients with schizophrenia.

OBJECTIVE: In order to assess the functional integrity of motor pathways through the corpus callosum (CC) in patients with schizophrenia transcallosally mediated inhibition (TI) of voluntary tonic EMG activity of first dorsal interosseus muscle following ipsilateral focal transcranial magnetic stimulation (fTMS) was investigated. In addition thickness and length of CC were calculated. METHOD: Twelve patients suffering from schizophrenia and 12 healthy controls were investigated. CC morphology was measured in mid-sagittal MRI-slices. Latency and duration of TI were calculated. RESULTS: In schizophrenics the duration of TI was significantly prolonged, whereas latencies were not. In addition, a lack of TI was found unilaterally in three patients. Measurements of CC revealed a significantly reduction of the length and thickness in the anterior part of CC in patients. CONCLUSION: These findings indicate that measurement of TI could be used to detect clinical silent affection of transcallosal motor pathways in schizophrenics. The effect of neuroleptic drugs has to be explored.

Adult↗
PubMed2001

The pro-sequence facilitates folding of human nerve growth factor from Escherichia coli inclusion bodies.

Nerve growth factor (beta-NGF), a neurotrophin required for the development and survival of specific neuronal populations, is translated as a prepro-protein in vivo. While the presequence mediates translocation into the endoplasmic reticulum, the function of the pro-peptide is so far unknown. As the pro-sequences of several proteins are known to promote folding of the mature part, the renaturation behaviour of recombinant human beta-NGF pro-protein was compared to that of the mature form. Expression of rh-pro-NGF in Escherichia coli led to the formation of inclusion bodies (IBs). The presence of the covalently attached pro-sequence significantly increased the yield and rate of refolding with concomitant disulfide bond formation when compared to the in vitro refolding of mature NGF (rh-NGF). Physicochemical characterization revealed that rh-pro-NGF is a dimer. The pro-peptide could be removed by limited proteolysis with trypsin yielding biologically active, mature rh-NGF. Furthermore, rh-pro-NGF exhibited biological activity in the same concentration range as rh-NGF.

Electrophoresis, Polyacrylamide Gel↗
PubMed2001

Rate matrices for analyzing large families of protein sequences.

We propose and study a new approach for the analysis of families of protein sequences. This method is related to the LogDet distances used in phylogenetic reconstructions; it can be viewed as an attempt to embed these distances into a multidimensional framework. The proposed method starts by associating a Markov matrix to each pairwise alignment deduced from a given multiple alignment. The central objects under consideration here are matrix-valued logarithms L of these Markov matrices, which exist under conditions that are compatible with fairly large divergence between the sequences. These logarithms allow us to compare data from a family of aligned proteins with simple models (in particular, continuous reversible Markov models) and to test the adequacy of such models. If one neglects fluctuations arising from the finite length of sequences, any continuous reversible Markov model with a single rate matrix Q over an arbitrary tree predicts that all the observed matrices L are multiples of Q. Our method exploits this fact, without relying on any tree estimation. We test this prediction on a family of proteins encoded by the mitochondrial genome of 26 multicellular animals, which include vertebrates, arthropods, echinoderms, molluscs, and nematodes. A principal component analysis of the observed matrices L shows that a single rate model can be used as a rough approximation to the data, but that systematic deviations from any such model are unmistakable and related to the evolutionary history of the species under consideration.

Computational Biology↗
PubMed2000

Measurement of the 1s-2s energy interval in muonium

The 1s-2s interval has been measured in the muonium (&mgr;(+)e(-)) atom by Doppler-free two-photon pulsed laser spectroscopy. The frequency separation of the states was determined to be 2 455 528 941.0(9.8) MHz, in good agreement with quantum electrodynamics. The result may be interpreted as a measurement of the muon-electron charge ratio as -1-1.1(2.1)x10(-9). We expect significantly higher accuracy at future high flux muon sources and from cw laser technology.

Journal Article↗
PubMed1999

Human nerve growth factor beta (hNGF-beta): mammary gland specific expression and production in transgenic rabbits.

Transgenic rabbits carrying gene constructs encoding human nerve growth factor beta (hNGF-beta) cDNA were generated. Expression of hNGF-beta mRNA was restricted to the mammary gland of lactating rabbits. Western Blot analysis revealed a polypeptide of 13.2 kDa in the milk of transgenic animals. hNGF-beta was purified from the milk by a two-step chromatographic procedure. Electrospray mass spectroscopy analysis of purified hNGF-beta depicted a molecular weight of 13,261 Da per subunit. The biological activity of the hNGF-beta was tested using PC12W2 cells and cultures of dorsal root ganglion neurons from chicken embryos. Crude defatted milk from transgenic animals and purified hNGF-beta demonstrated full biological activity when compared to commercial recombinant hNGF-beta.

Animals↗
PubMed1999

[Marchiafava-Bignami syndrome. Extrapontine myelinolysis in chronic alcoholism].

Until now, the pathogenesis of Marchiafava-Bignami disease, an extrapontine myelinolysis, is unknown. Accept an abuse of alcohol for many years additional metabolic and vascular disturbances are supposed. The early performance of magnetic resonance imaging in patients with a sudden encephalopathy and history of alcoholism is essential for an assessment of the diagnosis. The bilateral lack of transcallosal inhibition--a parameter for the integrity of the transcallosal connections between motor cortices--is the consequence of the axonal degeneration of transcallosal fibers. Clinical and neuroradiological features of three patients with extrapontine myelinolysis are reported and possible etiologies of the complex disease are discussed. In two cases a severe alcohol abuse was present with the typical picture of the Marchiafava-Bignami disease. In a third patient an intoxication with methanol was present with a similar clinical picture. Although severe neurological disturbances were initially apparent in the patients, during the follow-up there was a significant amelioration of the clinical course under a high-dose vitamin B supplementation.

Adult↗
PubMed1999

Demyelination and axonal degeneration in corpus callosum assessed by analysis of transcallosally mediated inhibition in multiple sclerosis.

OBJECTIVE: Following focal transcranial magnetic cortex stimulation (fTMS), inhibition of voluntary EMG activity in the ipsilateral first dorsal interosseus (FDI) muscle was studied, in order to assess the functional integrity of the corpus callosum in patients with multiple sclerosis (MS). METHODS AND RESULTS: Thirty-four patients suffering from definite MS and 12 healthy, age-matched normal subjects were examined. In mid-sagittal slices, 29 patients showed lesions within the truncus corporis callosi in T2-weighted MRI. In 20 patients, all areas (anterior, middle and posterior parts), in one both the anterior and posterior part, in 3 exclusively the anterior, in 4 the middle and in one the posterior area were affected. In 5 patients, lesions of corpus callosum were lacking. In normal subjects, fTMS elicited a transient inhibition (TI) of preactivated (50% of maximal force) isometric voluntary ipsilateral FDI muscle activity. Mean onset latencies of TI were 35.5+/-5.4 ms in right and 36.1+/-4.2 ms in left FDI. Mean duration of TI amounted to 23.0+/-8.4 ms for right and 24.6+/-8.4 ms for left FDI. In the MS group, TI latencies were significantly increased in 23 and TI durations in 16 cases, whereas a lack of TI was found in 5 patients bilaterally and in 6 unilaterally. In patients, mean onset latencies of TI were 40.4+/-13.8 ms in right and 43.3+/-14.4 ms in left FDI, TI duration amounted to 30.5+/-17.4 ms for right and 31.0+/-25.2 ms for left FDI. Increase of onset latencies and durations of TI were positively correlated with the summed area of lesions of corpus callosum in representative mid-sagittal MRI slices. Significant correlations between TI onset latencies and duration on the one hand, and central motor conduction latencies along corticospinal tracts (CML) on the other hand, were not found. CONCLUSION: The present investigation indicates that measurement of TI elicited by fTMS seems to be a sensitive method for an assessment of demyelination and axonal degeneration within corpus callosum in MS patients.

Adult↗
PubMed1999

Flexible management system for occupational safety and quality.

In the 10 analysed companies it is necessary to create a management for flexible processes and a structured flexibilisation of these processes. This represents the basis for the retention of existing flexibility and occupational safety. The strategy for a management of flexible processes leads, firstly, to a structuring of company procedures whilst still retaining the necessary flexibility and certification ability as laid down by standards No. DIN EN ISO 9000ff. and, secondly, to the keeping of the demands of an occupational safety management system. In this article the inclusion of co-workers stands in the foreground. This will be combined with the goal to utilise their experience and their acceptance of the solutions worked out.

Ergonomics↗
PubMed1998

Alterations in immune parameters associated with low level methylmercury exposure in mice.

Methylmercury (MeHg) is a known toxicant and continues to be a significant environmental contaminant. While the neurotoxicity and developmental toxicity of MeHg are well established, the immunotoxic effects of MeHg are just now being studied and described. This study evaluated strain and gender specific effects of low level, prolonged MeHg exposure in mice. Mice were exposed to MeHg in the drinking water (0, 3 or 10 ppm) for 4 weeks. Splenocytes and thymocytes were evaluated for alterations in immunophenotype, GSH levels, and intracellular Ca2+ flux after mitogen stimulation. MeHg exposure resulted in alterations in splenocyte and thymocyte subsets and a dose dependent decrease in GSH levels (as measured by monochlorobimane fluorescence and flow cytometry) of all splenocyte subsets. This decrease in GSH was further confirmed by biochemical assay in splenocytes. In addition, there was a dose response related decrease in mitogen stimulated Ca2+ flux and in the percentages of CD4+ splenocytes and CD8+ splenocytes from mice exposed to 10 ppm of MeHg. These results suggest that low-level chronic MeHg exposure may cause immune disfunction by disturbing thiol redox balance, transmembrane signaling and splenic cellularity.

Analysis of Variance↗
PubMed1996

Synergistic effects of thrombopoietin and granulocyte colony-stimulating factor on neutrophil recovery in myelosuppressed mice.

Severe suppression of the hematopoietic system is a major factor in limiting chemotherapy dose escalation. To determine whether a combination of human recombinant granulocyte colony-stimulating factor (G-CSF) and thrombopoietin (TPO) would alter recovery of platelets, red blood cells (RBCs), or neutrophils after myeloablative therapy, myelosuppressed mice were treated with sc injections of TPO (90 micrograms/kg), G-CSF (250 micrograms/kg). TPO plus G-CSF or vehicle and complete blood counts were measured. Marrow and spleen cells were obtained at various times and assayed for erythroid, myeloid, and megakaryocytic progenitors. The prolonged neutropenia in vehicle controls (14 days) was significantly shortened in mice treated with G-CSF or TPO for 14 days. The combination of TPO plus G-CSF further reduced the duration of neutropenia. TPO and TPO plus G-CSF treatments also significantly shortened thrombocytopenia compared to vehicle. Recovery of RBCs was also enhanced in mice treated with either G-CSF or TPO, or the combination. Furthermore, treatment with G-CSF and/or TPO hastened myeloid, erythroid, and megakaryocyte progenitor recovery compared to vehicle controls. These results show that the combination of TPO plus G-CSF acts synergistically to accelerate neutrophil recovery in myelosuppressed mice and does not compromise the platelet or RBC response to TPO therapy.

Animals↗
PubMed1996

Probenicid inhibition of fluorescence extrusion after MCB-staining of rat-1 fibroblasts.

The intracellular fluorescence level of cells stained continuously with monochlorobimane was monitored by flow cytometry in order to assess the initial rate of glutatione to monochlorobimane conjugation as a measure of glutathione S-transferase activity. In addition to a rapid initial increase and a plateau level, a decline in fluorescence intensity was found upon prolonged flow cytometric monitoring. Exposure to probenicid, an inhibitor of an ATP-dependent organic anion pump, prevented this decrease. Incubation with vanadate and verapamil was without effect. Thus, extrusion of fluorescentglutathione-conjugate perturbs the proportionality between initial glutathione level and monochlorobimane-dependent fluorescence intensity. Monitoring by flow cytometry the decrease in monochlorobimane-dependent fluorescence may be useful to detect multidrug resistant cells.

3T3 Cells↗