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C Reiter

Publications and source records attributed to C Reiter.

At least 19 recordsLinked to original sources
PubMed2003

Platinum determination by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) in different matrices relevant to human biomonitoring.

The analytical challenges of Pt determination by ICP-SFMS posed by different human tissues and fluids have been critically assessed. Investigated samples were (1) urine, (2) serum of cancer patients sampled during chemotherapy with carboplatin, (3) microdialysates (20 micro L sample volume) collected from tumor and non-tumor tissue, and, finally-for the first time-(4) human lung tissue to study background concentrations of inhaled platinum. Sample preparation involved microwave digestion and open vessel treatment or simple dilution (microdialysates). Depending on the sample preparation and introduction systems used (microconcentric nebulization, ultrasonic nebulization with and without membrane desolvation) excellent procedural detection limits (3s criterion) of 0.35 pg g(-1) for urine, 420 pg g(-1) for serum, 400 pg g(-1) for lung tissue and 13 pg g(-1) for microdialysates could be obtained. Ultratrace concentrations of 1-40 pg g(-1), and 1000-3000 pg g(-1) were measured in urine and human lung tissue, respectively, as typical for samples in environmental studies. Quantification was carried out by IDMS and standard addition in the case of urine samples. Internal standardization could not correct for non-spectral interferences in external calibration. In the serum and microdialysates of patients during chemotherapy with carboplatin, elevated Pt levels ranging between 0.01 and 10 micro g g(-1) were determined by external calibration ((195)Pt isotope). For all investigated samples spectral interferences could be excluded by following different strategies. High-resolution control measurements ((194)Pt, (195)Pt) were performed in the case of elevated Pt levels, i.e. for microdialysates and serum samples. An Hf/Pt ratio of 0.4 was determined in human lung samples. An HfO formation ratio of 0.2% was assessed for standard solutions at the present experimental conditions, revealing that the contribution of (179)Hf(16)O, (178)Hf(17)O, (177)Hf(18)O to the (195)Pt isotope signal used for quantification was not significant.

Blood Chemical Analysis↗
PubMed2001

[Drugs for young Mozart. Medical treatment of Wolfgang as a child by his father Leopold Mozart].

Leopold Mozart (1719-1787), father of Wolfgang Amadé, had profound medical knowledge and was a passionate medical dilettante. As long as the young Mozart lived with his father and travelled on his concert tours with him, Leopold cared for his son in medical matters. Doctors were only consulted occasionally. In the extensive correspondence of Mozart's father drugs and treatments used for Wolfgang Amadé are reported in detail. This represents a reliable description of the pharmacological therapies of the late 18th century. The mentioned drugs are, as far as possible, viewed from todays medical perspective.

Austria↗
PubMed2001

Effect of temperature on Lucilia sericata (Diptera: Calliphoridae) development with special reference to the isomegalen- and isomorphen-diagram.

Developmental behavior of eggs, larva and pupa of the blowfly species Lucilia sericata (Meigen) were studied under 10 different temperature regimes. Data from these studies were used to construct the isomegalen-diagram. In this diagram, time from hatching to peakfeeding is plotted against temperature, each line representing identical larval length at various temperatures. If the temperature is roughly constant, as is the case with corpses found indoors, the age of the maggot can be read off instantly from its length, provided that the maggot has not entered the migratory phase. Where temperature is variable, an age range can be estimated between the points where the measured larval length cuts the graph at the maximum and minimum temperatures recorded. Equally, the isomorphen-diagram representing all morphological stages from oviposition to eclosion should be used, if maggots in the migratory phase or pupae or puparia are recovered from the scene. The isomegalen- and the isomorphen-diagrams could facilitate a quick and more precise estimate of the postmortem interval even for the inexperienced investigator. In addition, our results vary from those of other investigators, suggesting a different thermal behavior of the holarctic blowfly L. sericata in various zoogeographic regions.

Animals↗
PubMed2001

L-arginine chlorination products inhibit endothelial nitric oxide production.

The myeloperoxidase-derived oxidant hypochlorous acid (HOCl) is thought to contribute to endothelial dysfunction, but the mechanisms underlying this inhibitory effect are unknown. The present study tested the hypothesis that HOCl and L-arginine (L-Arg) react to form novel compounds that adversely affect endothelial function by inhibiting nitric oxide (NO) formation. Using spectrophotometric techniques, we found that HOCl and L-Arg react rapidly (k = 7.1 x 10(5) m(-1) s(-1)) to form two major products that were identified by mass spectrometry as monochlorinated and dichlorinated adducts of L-Arg. Pretreatment of bovine aortic endothelial cells with the chlorinated L-Arg metabolites (Cl-l-Arg) inhibited the -induced formation of the NO metabolites nitrate (NO(3)(-)) and nitrite (NO(2)(-)) in a concentration-dependent manner. Preincubation of rat aortic ring segments with Cl-L-Arg resulted in concentration-dependent inhibition of acetylcholine-induced relaxation. In contrast, blood vessels relaxed normally to the endothelium-independent vasodilator sodium nitroprusside. In vivo administration of Cl-L-Arg to anesthetized rats increased carotid artery vascular resistance. A greater than 10-fold excess of L-Arg was required to reverse the inhibitory effects of Cl-L-Arg in vivo and in vitro. Reaction of HOCl with D-arginine (D-Arg) did not result in the formation of inhibitory products. These results suggest that HOCl reacts with L-Arg to form chlorinated products that act as nitric-oxide synthase inhibitors.

Animals↗
PubMed1999

Induction of nitric oxide-dependent apoptosis in motor neurons by zinc-deficient superoxide dismutase.

Mutations in copper, zinc superoxide dismutase (SOD) have been implicated in the selective death of motor neurons in 2 percent of amyotrophic lateral sclerosis (ALS) patients. The loss of zinc from either wild-type or ALS-mutant SODs was sufficient to induce apoptosis in cultured motor neurons. Toxicity required that copper be bound to SOD and depended on endogenous production of nitric oxide. When replete with zinc, neither ALS-mutant nor wild-type copper, zinc SODs were toxic, and both protected motor neurons from trophic factor withdrawal. Thus, zinc-deficient SOD may participate in both sporadic and familial ALS by an oxidative mechanism involving nitric oxide.

Amyotrophic Lateral Sclerosis↗
PubMed1999

Intimal hyperplasia of the infant parasellar carotid artery: a potential developmental factor in atherosclerosis and SIDS.

Intimal cushions that project into the lumen of arteries are precursors of atherosclerotic plaque formation. The "carotid siphon, " although frequently affected by atherosclerosis, was never analyzed for the occurrence of neonatal intimal hyperplasia. This study provides a topographic and morphometric analysis of intimal cushions in the parasellar internal carotid artery (pICA) of the human infant. A total of 35 specimens were studied in detail, using both standard histological techniques and a new method of computer-aided 3D reconstruction. Intimal hyperplasia occurred at 3 characteristic locations of the pICA: (1) the convex side of the posterior knee (C5 cushion), (2) the bottom of the horizontal segment (C4 cushion), and (3) the concave side of the anterior knee (C3 cushion). The extension of the cushions and the degrees to which they occluded the vessel lumens were measured. The complex shape of the pICA required 3D computer models for exact topographical descriptions and precise measurements. Our results suggest that the occurrence and degree of intimal hyperplasia are related to shape changes of the pICA during postnatal development. We predict that individuals who retain the relatively straight course of the fetal pICA throughout their lives are less prone to develop atherosclerotic lesions at this portion of the carotid artery. A possible contribution of neonatal intimal cushions to the origin of sudden infant death syndrome is discussed.

Arteriosclerosis↗
PubMed1999

Neuropil pattern formation and regulation of cell adhesion molecules in Drosophila optic lobe development depend on synaptobrevin.

To investigate a possible involvement of synaptic machinery in Drosophila visual system development, we studied the effects of a loss of function of neuronal synaptobrevin, a protein required for synaptic vesicle release. Expression of tetanus toxin light chain (which cleaves neuronal synaptobrevin) and genetic mosaics were used to analyze neuropil pattern formation and levels of selected neural adhesion molecules in the optic lobe. We show that targeted toxin expression in the developing optic lobe results in disturbances of the columnar organization of visual neuropils and of photoreceptor terminal morphology. IrreC-rst immunoreactivity in neuropils is increased after widespread expression of toxin. In photoreceptors, targeted toxin expression results in increased Fasciclin II and chaoptin but not IrreC-rst immunoreactivity. Axonal pathfinding and programmed cell death are not affected. In genetic mosaics, patches of photoreceptors that lack neuronal synaptobrevin exhibit the same phenotypes observed after photoreceptor-specific toxin expression. Our results demonstrate the requirement of neuronal synaptobrevin for regulation of cell adhesion molecules and development of the fine structure of the optic lobe. A possible causal link to fine-tuning processes that may include synaptic plasticity in the development of the Drosophila CNS is discussed.

Animals↗
PubMed1999

Three-dimensional reconstruction of the antennal lobe in Drosophila melanogaster.

We present the first three-dimensional map of the antennal lobe of Drosophila melanogaster, based on confocal microscopic analysis of glomeruli stained with the neuropil-specific monoclonal antibody nc82. The analysis of confocal stacks allowed us to identify glomeruli according to the criteria shape, size, position, and intensity of antibody labeling. Forty glomeruli were labeled by nc82, eight of which have not been described before. Three glomeruli previously shown exclusively by backfills were not discernible in nc82 stainings. We distinguish three classes of glomeruli: (1) "landmark" glomeruli that are constant in all four criteria mentioned above, (2) less well-demarcated glomeruli that deviate in a single criterion, and (3) poorly defined glomeruli that vary in more than one criterion. All class 2 and 3 glomeruli can be identified by comparison with landmark neighbors. To further aid identification, our model assigns glomeruli to five arrays, each of which is defined by a prominent landmark glomerulus. Six glomeruli consist of distinct, but contiguous structural units, termed "compartments." Glomerular variability observed occasionally between males and females is in the same range as between individuals of the same sex, suggesting the lack of a significant sexual dimorphism in the glomerular pattern. We compare the new model with a previous map and address its potential for mapping activity and expression patterns. An important goal of this work was to create three-dimensional reference models of the antennal lobe, which are accessible on-line.

Animals↗
PubMed1999

Irregular chiasm-C-roughest, a member of the immunoglobulin superfamily, affects sense organ spacing on the Drosophila antenna by influencing the positioning of founder cells on the disc ectoderm.

We describe a role for Irregular chiasmC-roughest (IrreC-rst), an immunoglobulin (Ig) superfamily member, in patterning sense organs on the Drosophila antenna. IrreC-rst protein is initially expressed homogeneously on apical profiles of ectodermal cells in regions of the antennal disc. During specification of founder cells (FCs), the intracellular protein distribution changes and becomes concentrated in regions where specific intercellular contacts presumably occur. Loss of function mutations as well as misexpression of irreC-rst results in an altered arrangement of FCs within the disc compared to wildtype. Sense organ development occurs normally, although spacing is affected. Unlike its role in interommatidial spacing, irreC-rst does not affect apoptosis during antennal development. We propose that IrreC-rst affects the spatial relationship between sensory and ectodermal cells during FC delamination.

Animals↗
PubMed1999

Detection of humoral rejection in human cardiac allografts by assessing the capillary deposition of complement fragment C4d in endomyocardial biopsies.

BACKGROUND: There are no well-established diagnostic criteria to detect humoral rejection in organ transplantation. The value of commonly used markers in immunohistochemistry, such as C1q, C3c, IgG, IgM and fibrinogen, is questioned by some groups. Complement fragment C4d is a more stable marker of complement activation as it is covalently bound to graft capillaries. C4d has been shown to identify clinically relevant, but otherwise undetectable humoral anti-graft reactions in human kidney transplants. METHODS: Immunohistochemical techniques were used to evaluate 155 endomyocardial biopsies from 56 heart transplant recipients less than 3 months post transplantation for the presence of capillary C4d staining. In a subset of patients, C4d staining was compared with C1q, C3c, IgM and fibrin staining and was correlated with clinical outcome. RESULTS: Within 3 months 9 of 56 patients died. Five of these nonsurvivors had prominent C4d staining (p < .05), whereas C1q, C3c and IgM showed no correlation with clinical outcome. Presence of fibrin correlated with clinical outcome and C4d staining (p < .05). CONCLUSIONS: The capillary deposition of complement split product C4d in human endomyocardial biopsies was significantly associated with graft loss. Determination of fibrin deposition may yield additional information to establish a diagnosis of humoral rejection. The immunohistochemical assessment of capillary deposition of C4d and fibrin appears to be an appropriate tool for the identification of patients, who may require additional or alternative immunosuppressive therapy targeted against the humoral immune system.

Adult↗
PubMed1999

A novel superoxide dismutase-based trap for peroxynitrite used to detect entry of peroxynitrite into erythrocyte ghosts.

Peroxynitrite (ONOO-) is a relatively stable oxidant produced by activated macrophages and neutrophils. To detect peroxynitrite, a novel human superoxide dismutase (SOD) trap was developed by substituting a tyrosine near the copper in the active site. The copper can catalyze nitration of this tyrosine by peroxynitrite. The nitrated tyrosine can serve as a reporter for peroxynitrite by measuring the extent of nitration with Western blots developed with a nitrotyrosine antibody. The new SOD mutant differs from bovine SOD whose sole tyrosine is far removed from the active site. Nitration of bovine SOD was second-order with respect to SOD concentration, whereas nitration of the new mutant SODs followed first-order kinetics with respect to peroxynitrite. The tyrosine SODs were used to assess whether peroxynitrite crosses erythrocyte membranes through the band 3 anion exchange protein. Tyrosine-containing SOD entrapped within normal human erythrocyte ghosts became nitrated in proportion to peroxynitrite concentration. The band 3 anion exchange protein inhibitors, phenyl isothiocyanate (PITC) and 4, 4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS), inhibited up to 90% of the nitration. The erythrocyte membrane proteins, spectrin, band 3 anion exchange protein, and proteins 4.1 and 4.2, were also nitrated. Nitration of erythrocyte membrane proteins was also inhibited by PITC and DIDS. These data suggest that the band 3 anion exchange protein is the major route for the entry of peroxynitrite into erythrocytes. The ability of peroxynitrite to cross cell membranes can contribute to its toxicity by allowing access to intracellular target molecules.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1997

Depletion of CD8+ T lymphocytes by murine monoclonal CD8 antibodies and restored specific T cell proliferation in vivo in a patient with chronic hepatitis C.

Cellular immune mechanisms, especially those mediated by CD8+ T cells, are important in the pathogenesis and control of viral infections. On the other hand, as shown for chronic lymphocytic choriomeningitis virus infection in the mouse, CD8+ T cells may not only hinder the elimination of a virus, but make the host unresponsive to a second viral infection. In hepatitis C virus (HCV) infections, at least 50% of the patients become chronically infected, despite the detection of HCV-specific CTL and a specific proliferative response to HCV Ags in PBL and in lymphocytes isolated from the liver. To better understand the immunopathologic mechanisms of CD8+ cells in vivo and to search for a potential treatment, we applied murine CD8 mAbs to a patient with therapy-resistant chronic HCV. A drastic reduction of CD8+ circulating lymphocytes, a reduction of CD8 molecule density, and complement fixation on CD8+ cells were observed. The reduction of CD8+ cells was compensated partially by an elevation of CD4+ cells. High concentrations of neutralizing human anti-mouse Abs were induced. After the Ab infusions, the CD4/CD8 ratio in peripheral blood increased from 1.6 to values of about 3 during therapy, and gradually decreased to 2.3 1 yr after the last mAb infusion. A continuing decrease of serum aminotransferases and clinical improvement was observed. Interestingly, after initiation of treatment, a significant proliferative response to HCV-specific Ags became measurable.

Adult↗
PubMed1997

Investigation of the triacylglycerol composition of iceman's mummified tissue by high-temperature gas chromatography.

The pattern of intact triacylglycerols of a skin sample from the 5300-year-old Iceman mummy (nicknamed Otzi) was resolved on a diphenyl-dimethylpolysiloxane stationary phase by high-temperature gas chromatography. Adipocere from a 64-year-old glacier mummy as well as recent human subcutaneous fat served as a comparison in this study. Qualitatively, the results for mummy samples were similar with well-preserved saturated, but decomposed unsaturated, triacylglycerols, the latter being predominant in subcutaneous fat. Excellent preservation of triacylglycerols with odd carbon numbers and branched acyl chains was observed. The results presented here shed new light on the process of mummification.

Adipose Tissue↗
PubMed1996

Treatment of severe cutaneous lupus erythematosus with a chimeric CD4 monoclonal antibody, cM-T412.

BACKGROUND: Monoclonal CD4 antibodies are among the most potent immunomodulatory agents in various experimental models of autoimmune disease, including murine lupus erythematosus. OBJECTIVE: The aim of this study was to evaluate the toxicity and therapeutic efficacy of a chimeric monoclonal CD4 antibody, cM-T412, in patients with cutaneous lupus erythematosus (LE). METHODS: Five patients with severe cutaneous LE lesions received intravenously a total of 275, 400, or 475 mg of cM-T412 in single doses of 20 to 50 mg during a period of 5 to 8 weeks. RESULTS: CD4 antibody treatment induced a long-lasting decrease in disease activity. It resulted in healing of LE skin lesions, a reconstituted responsiveness to conventional treatment, or both. Despite a substantial depletion of circulating CD4+ T lymphocytes, no clinical signs of immunosuppression were noted. CONCLUSION: Monoclonal CD4 antibodies should be considered as a novel treatment for the management of severe cutaneous LE.

Adjuvants, Immunologic↗
PubMed1996

Structural diversity of monoclonal CD4 antibodies and their capacity to block the HIV gp120/CD4 interaction.

A number of monoclonal antibodies have been raised against CD4, the receptor on T cells for the HIV envelope glycoprotein gp120. In the present paper we describe biological activities and sequence analysis of seven CD4 MAb. Five of these MAb preparations compete with HIV/gp120 for CD4 binding. The sequences of the variable regions for these MAb were determined in order to ascertain any correlation with selective V gene usage. A relationship was found between the expressed variable region genes and the CD4 recognition pattern. The VH genes that are used can be subdivided into two major groups expressing either a VH gene belonging to the J558 family or to the VGam family. The usage of the VL genes varies, indicating that the epitope specificity is predominantly determined by the rearranged VH genes. The distinct cross-reactivity pattern of these MAb also correlates with their capacity to block binding of recombinant gp120 to CD4 in vitro. Although five of these MAb were able to block gp120 binding none of the CDR sequences shows a relevant homology to the gp120 sequence. This indicates a steric hinderence mechanism for blocking gp120 binding and not a direct interaction with the receptor binding site on CD4. The data also confirm the failure of these MAb as a potential target for receptor mimicry.

Amino Acid Sequence↗
PubMed1996

Reorganization of membrane contacts prior to apoptosis in the Drosophila retina: the role of the IrreC-rst protein.

The final step of pattern formation in the developing retina of Drosophila is the elimination of excess cells between ommatidia and the differentiation of the remaining cells into secondary and tertiary pigment cells. Temporally and spatially highly regulated expression of the irregular chiasmC-roughest protein, an adhesion molecule of the immunoglobulin superfamily known to be involved in axonal pathfinding, is essential for correct sorting of cell-cell contacts in the pupal retina without which the ensuing wave of apoptosis does not occur. Irregular chiasmC-roughest accumulates strongly at the borders between primary pigment and interommatidial cells. Mutant and misexpression analysis show that this accumulation of the irregular chiasmC-roughest protein is necessary for aligning interommatidial cells in a single row. This reorganisation is a prerequisite for the identification of death candidates. Irregular chiasmC-roughest function in retinal development demonstrates the importance of specific cell contacts for assignment of the apoptotic fate.

Animals↗