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S Meyer

Publications and source records attributed to S Meyer.

At least 127 records · Page 7Linked to original sources
PubMed1997

[To stay fit inspite of injury].

Optimal rehabilitation after injuries has become increasingly important in recent years. In our concept, not only the damaged local structure is treated but supplementary training to improve the general physical performance is recommended. This specific training includes the components of strength, endurance, coordination, flexibility and velocity. We explain in the present article the role of these rehabilitative methods and refer to their importance for the reintegration process following injuries.

Athletic Injuries↗
PubMed1997

The influence of fixation delay on mitotic activity and flow cytometric cell cycle variables.

Proliferation variables such as mitotic activity and the percentage of S-phase cells have been shown to be of prognostic value in many tumors, especially in breast cancer. However, some studies reported a decrease in mitotic activity caused by delay in fixation of the tissue. In contrast, other studies showed that the identifiability of mitotic figures decreases after fixation delay, but the total number of mitotic figures and also the percentage of S-phase cells remain unchanged. Most studies have been done on small numbers of experimental tumors, thus introducing the risk of selection bias. The aim of this study was to reinvestigate the influence of fixation delay on mitotic activity and cell cycle variables assessed by flow cytometry in an adequate number of resected human tissues to reach firmer conclusions. Resection specimens of 19 and 21 cases, respectively, for the mitotic activity estimate and the flow cytometric percentage of S-phase calculation were collected directly from the operating theater using lung, breast, and intestinal cancers and normal intestinal mucosa. The tissues were cut in pieces, and from each specimen, pieces were fixed in 4% buffered formaldehyde (for mitosis counting) as well as snap frozen (for flow cytometry) immediately after excision, as well as after a fixation delay of 1, 2, 4, 6, 8, 18, and 24 hours. Moreover, during the fixation delay, one series from each specimen was kept in the refrigerator and the second at room temperature. Thus, a total of 304 (19 X 16) and 336 (21 X 16) specimens were investigated for the mitotic activity estimate and the percentage of S-phase cells calculation, respectively. With regard to the estimation of the mitotic activity, both clear and doubtful mitotic figures were registered separately, obtaining an "uncorrected" and "corrected" (for doubtful mitotic figures) mitotic activity estimate. The percentage of S-phase cells was obtained by cell cycle analysis of flow cytometric DNA-histograms. The results showed that the quality of the material decreased during the fixation delay, as reflected by poorer cellular morphology in the hematoxylin-and-eosin-stained slides, resulting in more difficult identification of mitotic figures and a more time-consuming procedure with regard to the mitosis counts, but not in a worse intraobserver and interobserver reproducibility, which was acceptable. The reduction in quality of the tissues also was shown by the flow cytometric measurements because the coefficient of variation and percentage of debris increased after 4 hours or more of fixation delay. However, the mean values of the "uncorrected" mitotic activity and the "corrected" mitotic activity showed no decreasing trend; neither did the average percentage of S-phase cells. In conclusion, within the time investigated, fixation delay has no clear influence on the proliferation features studied. Because of the decreasing quality of the histological sections, resulting in more difficult identification of mitoses and interpretation of DNA histograms, fixation delay should be kept as short as possible, keeping the tissue at 4 degrees C until fixation.

Flow Cytometry↗
PubMed1997

Perioperative anti-endotoxin strategies.

Lipopolysaccharides from the outer membrane of Gram-negative bacteria are potent stimuli for the production of numerous cytokines by the immune cells. The systemic inflammatory response to these gut-derived endotoxins is therefore dependent on the responsiveness of the immune system. This paper presents results on anti-endotoxin strategies and the responsiveness to endotoxin in animal models of liver failure. Following partial hepatectomy in the normal rat, anti-endotoxin treatment using the enteral endotoxin binder cholestyramine and the bactericidal permeability-increasing protein showed beneficial effects in terms of reducing the exaggerated metabolic and inflammatory responses. Similar beneficial effects of gut endotoxin restriction were found in bile duct ligated rats subjected to a laparotomy. The beneficial effects of anti-endotoxin strategies in these models were explained by completely different mechanisms. In partial hepatectomized rats the effects were explained by the direct inhibition of the stimulatory action of endotoxin on immune cells preventing an exaggerated inflammatory response. In contrast, in postoperative BDL rats the effects of anti-endotoxin therapy were explained by the restoration of endotoxin sensitivity of the immune cells resulting in an inflammatory response necessary for an adequate reaction to surgery. These different mechanism will be discussed in the light of the phenomenon of endotoxin tolerance.

Animals↗
PubMed1997

Granulocyte macrophage colony stimulating factor pretreatment induces an increase of rat Kupffer cells with enhanced cytotoxicity in vitro and prevention of tumor outgrowth in vivo.

Male Wag rats were pretreated for 7 days with 1000 U/ml recombinant murine granulocyte macrophage colony stimulating factor (rmGM-CSF). Rat Kupffer cells (KC) were isolated by a enzymatic method. We injected decreasing numbers of CC531 tumor cells in the portal system. Mean KC yield increased from 1.5 +/- 0.2 to 2.2 +/- 0.2 (p < 0.05). Mean percentage of KC-mediated cytotoxicity against CC531 increased from 20.0 +/- 0.5 to 42 +/- 1.0 after rmGM-CSF (p < 0.05). At 1 x 10(5) CC531 tumor cells we demonstrated prevention of formation of small foci of CC52+ tumor cells. We demonstrate increased isolated KC with enhanced cytotoxic capacity after rmGM-CSF. rmGM-CSF induced prevention of minimal residual disease in the rat liver.

Animals↗
PubMed1997

Classification of "Pseudomonas azotocolligans" Anderson 1955, 132, in the genus Sphingomonas as Sphingomonas trueperi sp. nov.

"Pseudomonas azotocolligans" ATCC 12417T (T = type strain), which was described as a diazotrophic bacterium, was reinvestigated to clarify its taxonomic position. 16S ribosomal DNA sequence comparisons demonstrated that this strain clusters phylogenetically with species of the genus Sphingomonas and represents a new species. The results of investigations of the fatty acid patterns, polar lipid profiles, and quinone system supported this placement. The substrate utilization profile and biochemical characteristics displayed no obvious similarity to the characteristics of any previously described species of the genus Sphingomonas. The new name Sphingomonas trueperi is proposed on the basis of these results and previously published data for the G + C content of the genomic DNA and the polyamine pattern.

Base Composition↗
PubMed1997

The V3-directed immune response in natural human immunodeficiency virus type 1 infection is predominantly directed against a variable, discontinuous epitope presented by the gp120 V3 domain.

The specific binding of antibodies to the V3 loop in sera from human immunodeficiency type 1 (HIV-1)-infected individuals was investigated. Different V3 structures were analyzed as full-length loops or by pepscan. Our data show that on full-length V3 loops, both variable regions on either side of the tip of the loop (GPGRAF) contribute to a common epitope for type-specific antibodies. Type-specific antibodies bound strongly and at high titers to native V3 loops but negligibly once the loop was denatured. In contrast to the type-specific, discontinuous epitope, the linear, conserved epitopes presented by the full-length V3 loop, the tip, the amino-terminal base, and the carboxy-terminal base were not accessible to serum antibody. When the V3 sequences were analyzed with linear peptides, antibodies bound preferentially to peptides containing the conserved GPGRAF sequence. Thus, two different specificities of V3-directed antibodies were detected in patient sera. Unlike group-specific antibodies directed against GPGRAF peptides, lack of type-specific antibodies directed against the discontinuous epitope was correlated with viral escape from autologous neutralization. Our data suggest that the full-length conformation of the V3 loop is accessible predominantly to highly type-specific antibodies present in sera from HIV-1-infected individuals. These antibodies are directed against discontinuous V3 epitopes, not against conserved linear V3 targets. The implications of these findings for viral escape and blockade of infection with V3-based vaccines are discussed.

Amino Acid Sequence↗
PubMed1996

Alpha-tocopherol as a reductant for Cu(II) in human lipoproteins. Triggering role in the initiation of lipoprotein oxidation.

Initiation of lipid peroxidation by Cu(II) requires reduction of Cu(II) to Cu(I) as a first step. It is unclear, however, whether this reaction occurs in the course of lipoprotein oxidation. It is also unknown which reductant, if any, can drive the reduction of Cu(II) in this case. We found that Cu(II) was rapidly reduced to Cu(I) by all major human lipoproteins (high, low, and very low density lipoproteins (HDL, LDL, and VLDL), and chylomicrons). Cu(II)-reducing activity was associated with a lipid moiety of the lipoproteins. The rates of Cu(II) reduction by different lipoproteins were similar when the lipoproteins were adjusted to similar alpha-tocopherol concentrations. Enriching lipoproteins with alpha-tocopherol considerably increased the rate of CU(II) reduction. CU(II) reduction by alpha-tocopherol-deficient LDL isolated from a patient with familial inherited vitamin E deficiency was found to occur much slower in comparison with LDL isolated from a donor with a normal plasma level of alpha-tocopherol. Initial rate of CU(II) reduction by alpha-tocopherol-deficient LDL was found to be zero. Enriching LDL with ubiquinol-10 to concentrations close to those of alpha-tocopherol did not influence the reaction rate. When LDL was treated with ebselen to eliminate preformed lipid hydroperoxides, the reaction rate was also not changed significantly. CU(II) reduction was accompanied by a consumption of lipoprotein alpha-tocopherol and accumulation of conjugated dienes in the samples. Increasing alpha-tocopherol content in lipoproteins slightly decreased the rate of conjugated diene accumulation in LDL and HDL and considerably increased it in VLDL. The results suggest that alpha-tocopherol plays a triggering role in the lipoprotein oxidation by CU(II), providing its initial step as follows: alpha TocH + CU(II) --> alpha Toc. + Cu(I) + H+. This reaction appears to diminish or totally eliminate the antioxidative activity of alpha-tocopherol in the course of lipoprotein oxidation.

Adult↗
PubMed1996

Stress urinary incontinence due to a low-pressure urethra: a socially invalidizing disease.

To compare the quality of life and clinical findings of patients with low-pressure urethra (LPU: < or = 20 cm H2O) with those of stress urinary incontinent (SUI) patients without LPU, and to compare the quality of urethral sphincter (US) muscle innervation parameters in LPU patients with those in control continent patients. Historical, clinical, urodynamic, and US muscle innervation parameters were compared in 38 LPU (group 1), 241 SUI (group 2), and 7 control patients (group 3). In comparison with group 2, the incidence of previous surgery and daily incontinence episodes, SUI severity, and pad test values were significantly higher in group 1, whereas the incidence of previous traumatic deliveries was the same in both groups. The mobility of the bladder neck assessed by the Q-Tip test was significantly reduced in group 1. In comparison with group 3, US motor unit potential (MUP) duration and pudendal motor latencies to the urethral sphincter (PMLUS) were increased in LPU group 1 patients, whereas there was no difference in these parameters between LPU patients with or without previous incontinence surgery. Fifty-three percent of our LPU patients had normal PMLUS, but showed signs of abnormal reinnervation on quantitative electromyography. Three nullipara LPU patients had normal MUP durations and PMLUS values, but a decreased area in response to pudendal nerve stimulation. Apart from a rare form of LPU in nullipara patients, probably due to a dysgenesis of their US muscle, LPU patients suffer from neuro-muscular damage responsible for a severe urinary invalidity. Previous incontinence surgery, as well as previous vaginal deliveries, may be responsible for such US damage.

Adult↗
PubMed1996

Nerve growth factor delivery by gene transfer induces differential outgrowth of sensory, motor, and noradrenergic neurites after adult spinal cord injury.

Several neurotrophic factors have been identified that influence neuronal populations during central nervous system development, maturation, and senescence. To examine the responsiveness of the intact and the lesioned adult mammalian spinal cord to neurotrophic factors, primary rat fibroblasts were genetically modified to produce and secrete human nerve growth factor (NGF). These NGF-producing cells were then grafted to nonlesioned or lesioned adult rat spinal cords for periods of up to 1 year in vivo. Robust outgrowth of sensory and noradrenergic neurites was elicited by grafts in the previously nonlesioned spinal cord. Equally robust growth of sensory and noradrenergic neurites was observed in the lesioned spinal cord; in addition, partial sprouting of local motor neurites was elicited in the lesioned spinal cord. Thus, multiple neuritic populations of the adult spinal cord respond to neurotrophic factors by extending neurites, and this responsiveness is maintained and extended after major injury. Nerve growth factor delivered by somatic gene transfer may be a useful means of promoting axon regrowth in the injured spinal cord.

Adrenergic Fibers↗
PubMed1996

The assessment of bladder neck position and mobility in continent nullipara, mulitpara, forceps-delivered and incontinent women using perineal ultrasound: a future office procedure?

The purpose of this study was to assess the effects of spontaneous and instrumented deliveries, the baby's birthweight, the presence of stress incontinence and the woman's age and weight on bladder neck (BN) position and mobility using perineosonography, a simple non-invasive method, and to compare these results with those from continent nulliparous controls. Two hundred and fourteen women, including 74 nullipara, 29 para-1, 64 para-2 and 3, 16 with previous forceps deliveries and 32 with stress incontinence, underwent perineosonography with measurements of BN position and backwards/downwards displacement of BN using a two-axis calculation system. Results showed that bladder neck position undergoes a significantly backwards and downwards displacement on assuming an upright position. When compared with nulliparous controls, the bladder neck position at rest was the same in all groups of parous women in the supine/standing positions, but lower in patients having undergone forceps delivery (standing position) and in stress incontinent patients (both supine and standing); the bladder neck position during Valsalva was significantly lower in all groups of patients in the standing position, but the only significant difference in the supine position was seen in stress incontinent patients; the extent of bladder neck displacement was not significantly different between the groups, except in stress incontinent patients. A strong correlation (r = 0.66) was found between the relative importance of backwards and downwards displacement, but no correlation was found between bladder neck displacement and baby's birth-weight or patient's weight. It was concluded that compared to nulliparous continent patients, normal and instrumented delivery induces no modifications of BN position at rest, but is responsible for a lower bladder neck position during Valsalva in the standing position only. The extent of BN displacement is virtually the same in all groups of patients in both positions, except for stress incontinent patients, who have a significantly lower and more mobile bladder neck, the values of which overlap to a great extent (sensitivity of 78%/75% for a displacement > 14 mm) within those seen in continent nulliparous women. The correlation between the importance of backwards and downwards displacement is strong, making superfluous a two-dimensional coordinate system for routine BN position/mobility assessment.

Age Factors↗
PubMed1996

Determination of inorganic ionic mercury down to 5x10(-14) mol l(-1) by differential-pulse anodic stripping voltammetry.

A new method is described for the reliable and ultrasensitive determination of inorganic ionic mercury, using differential-pulse anodic stripping voltammetry on a glassy carbon electrode. It has been possible to determine mercury down to a concentration of 5x10(-14) mol l(-1) (the lowest detection limit ever reported for a voltammetric method). This success was achieved by using a thiocyanate electrolyte and relatively long deposition times. The mercury ions are stabilized in the solution by the formation of strong thiocyanate complexes. This leads to a highly reproducible cathodic plating and anodic dissolution of mercury. A speciation analysis allowing to distinguish between dissolved atomic and ionic mercury in water is possible.

Journal Article↗
PubMed1996

Central infusions of brain-derived neurotrophic factor and neurotrophin-4/5, but not nerve growth factor and neurotrophin-3, prevent loss of the cholinergic phenotype in injured adult motor neurons.

Neurotrophic factors are molecules that prevent neuronal degeneration and regulate neuronal phenotype during either development or adulthood. Relatively little is known about the comparative responsiveness of injured adult central nervous system motor neurons to various neurotrophic factors. In the present study we examined the effects of four members of the neurotrophin family on injured adult motor neurons. Nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3 or neurotrophin-4/5 were infused intracerebroventricularly into adult rats following transection of the motor hypoglossal nerve. Two weeks after axotomy, brain-derived neurotrophic factor and neurotrophin-4/5 completely prevented the loss of the cholinergic phenotype in hypoglossal motor neurons (97 +/- 11% and 99 +/- 5%, respectively) as assessed by choline acetyltransferase immunolabeling. In contrast, nerve growth factor and neurotrophin-3 exerted no protective effect. The low-affinity p75 neurotrophin receptor, capable of binding all four neurotrophins, was re-expressed in injured hypoglossal neurons; the majority of injured hypoglossal neurons also express trkB receptors but not trkA or trkC receptors. Thus, injury-induced responses to neurotrophins in adult motor neurons are mediated by trk receptors and their agonists, but may or may not also require low-affinity p75 neurotrophin receptors. Intracerebroventricular infusions of trkB agonists may be a useful means of targeting multiple and distantly separated populations of motor neurons for neurotrophic factor therapy.

Animals↗
PubMed1996

Biomarker studies in northern Bohemia.

Studies were conducted in northern Bohemia to simultaneously evaluate personal exposures to air pollution in the form of respirable particles containing polycyclic aromatic hydrocarbons (PAHs) and biomarkers of exposure, biological effective dose, genetic effects, and metabolic susceptibility. The series of biomarkers included PAH metabolites in urine, urine mutagenicity, PAH-DNA adducts in white blood cells determined by 32P-postlabeling, PAH-albumin adducts determined by enzyme-linked immunosorbent assay (ELISA), DNA damage in lymphocytes detected by comet assay, chromosomal aberrations, sister chromatid exchanges, and glutathione S-transferase M1 (GSTM1) genotypes. For these studies, a group of women who work outdoors about 30% of their daily time was selected. In a pilot study, a group of women from a polluted area of the Teplice district (northern Bohemia) was compared with a group of women from a control district of southern Bohemia (Prachatice). In a follow-up repeated-measures study, a group of nonsmoking women from Teplice was sampled repeatedly during the winter season of 1993 to 1994. Personal exposure monitoring for respirable particles (< 2.5 microns) was conducted for the 24-hr period before collection of blood and urine. Particle extracts were analyzed for carcinogenic PAHs. In the pilot study and in the follow-up study, a highly significant correlation between individual personal exposures to PAHs and DNA adducts was found (r = 0.54, p = 0.016; r = 0.710, p < 0.001, respectively). The comet parameter (percentage DNA in tail; %T) correlated with exposures to respirable particles (r = 0.304, p = 0.015). The GSTM1 genotype had a significant effect on urinary PAH metabolites, urine mutagenicity, and comet parameters (% T and tail moment) when the GSTM1 genotype was considered as a single factor affecting these biomarkers. Multifactor analysis o variance considering exposure and adjusting the data for GSTM1, age, and diet showed that the effect of personal exposures to PAHs on the variability of biomarkers (DNA adducts, comet parameters, urine mutagenicity) might be higher than the effect of the GSTM1 genotype. These results show the importance of considering all potential factors that may affect the biomarkers being analyzed.

Adolescent↗
PubMed1996

Discrepancies in ultrasonography of the infant hip.

A total of 4,984 ultrasonographic (US) examinations of infant hips were done for the diagnosis or management of congenital/developmental dislocation/ dysplasia of the hip; 48 instances of lack of correlation (0.96%) between the US and radiographic images were noted. Analysis of these cases permitted classification into two groups: (a) apparent discrepancy (44 cases, 0.88%) for which faulty technique or interpretation of the sonogram/radiograph, hyperlaxity, inadvertent stress views, and lateral ossification defects led to disparity in the imaging modalities; and (b) true discrepancy (4 cases, 0.08%) where no explanation was possible for the dissimilarity. The relevance of this study is that the majority of discrepancies can be eliminated by (a) avoiding the common causes of apparent discrepancies mentioned in this article and by (b) the use of the Graf and Harcke techniques as complementary methods of US examination.

Female↗
PubMed1995

Enhanced human Kupffer cell-mediated cytotoxicity after activation of the effector cells and modulation of the target cells by interferon-gamma: a mechanistic study at the cellular level.

In this study we demonstrate enhanced Kupffer cell (KC) cytotoxicity against several colorectal cell lines by activation of KC and by modulation of the targets (SW948, WiDR, HT29, and SW620) with IFN-gamma. We demonstrated that soluble TNF-alpha had no effect on these tumor cells, while cytotoxicity against SW948 and WiDR was blocked by anti-TNF-alpha. Experiments using a transwell system stressed the importance of close intercellular contact for this process. Anti-IL-1 did not inhibit cytotoxicity against SW948. Modulation of HT29, WiDR, and SW948 by IFN-gamma (500 U/ml) induced a significant increase in cytotoxicity. We conclude that cell-associated TNF-alpha may be responsible for KC cytotoxicity against SW948, a process requiring close intercellular contact. WiDR is only partly lysed by a TNF-alpha-dependent mechanism, whereas HT29 is not. Furthermore, IFN-gamma is involved in the regulation of tumor susceptibility.

Cytotoxicity, Immunologic↗