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Biomedical subjects

S Schneider

Publications and source records attributed to S Schneider.

At least 19 recordsLinked to original sources

Regional administration of lymphokine-activated killer cells can be superior to intravenous application.

A patient with liver metastases of human lymphocyte antigen (HLA) class II-negative malignant melanoma was treated with several cycles of adoptive immunotherapy with interleukin-2 and lymphokine-activated killer (LAK) cells. The authors evaluated the efficacy of regional transfer of LAK cells versus systemic intravenous administration. Initially, the patient was treated according to a regional treatment protocol, consisting of perfusion of the spleen with interleukin-2 and transfer of LAK cells into the portal vein; a partial remission was observed. Because of technical problems, interleukin-2 and LAK cells were administered intravenously in a second treatment cycle. This systemic treatment course resulted only in a minor mixed response of the hepatic metastases. A third treatment course was administered with the use of intravenous interleukin-2 infusion and arterial perfusion of the liver with LAK cells. The patient had separate hepatic arteries to both lobes of the liver as an anatomic variation. Because most of the tumor mass was present in the right lobe of the liver, a third of the LAK cells were injected into the right hepatic artery and the remaining cells were administered intravenously. The lesions in the right lobe of the liver regressed, but disease progression occurred in the left lobe. A fourth treatment cycle, consisting of intravenous infusion of interleukin-2 and arterial perfusion of both lobes of the liver with LAK cells, resulted in a complete response of all hepatic lesions, which has lasted 18 months to date. Because, in this patient, tumor regression was observed only in anatomic areas of the liver, which were perfused with LAK cells, it is suggested that the regional administration of LAK cells was essential for successful treatment.

Adult

Patchy accumulation of apical Na+ transporters allows cross talk between extracellular space and cell nucleus.

Intracellular Na+ activities and local current densities were measured in fused Madin-Darby canine kidney cells using Na+ and voltage-sensing microelectrodes. Na+ that enters the cell across the apical plasma membrane accumulates initially in the nucleoplasm, several seconds ahead of its appearance in the cell cytoplasm. The spatial distribution of Na+ currents, produced by a local superfusion of the cell surface, indicates a nonuniform, patchy accumulation of apical Na+ transporters in the vicinity of the nucleus. Such pathways for direct Na+ flux between extracellular space and cell nucleus could be potentially important for gene activation.

Animals

Tolerance of self induced in thymus organ culture.

F liver protein occurs in serum at low concentration, and therefore induces tolerance of self only in T cells. T cells which mature in cultured thymus lobes in the absence of this protein become reactive towards it but can be prevented from doing so by exposure to the protein while in culture. The threshold of tolerance induction for this soluble antigen is estimated in this way at approximately 1 microgram/ml, which is slightly less than the threshold of response of primed T cells in a proliferation assay. Freshly isolated thymocytes do not display reactivity to self-F protein, indicating that T cells normally become tolerant while still within the thymus.

Animals

Wilms' tumor-specific methylation pattern in 11p13 detected by PFGE.

The analysis of 2,550 kb from 11p13 in Wilms' tumor (WT) material revealed two regions that differed significantly in their methylation between tumor and normal tissue. In WT a hypomethylated area defined by an NruI and MluI recognition site 100-150 kb centromeric of the WT gene WT1 (site A) and hypermethylation defined by an NruI and SacII site 100 kb telomeric of the WT1 gene were found (site B). The degree of methylation in region B varied between 20 and 100% in the different samples; the highest level was observed in tumors without preoperative chemotherapy. The CpG island 5' of the WT1 gene was partially methylated in 2/29 tumors analyzed. The methylation state of regions A and B could reflect the normal pattern present in a subset of embryonal kidney cells, from which WT develops.

Blotting, Northern

[The determinants of wear behavior in treatment with removable orthodontic appliances].

The interplay of significant determinants of patient appliance wear is discussed in terms of a conceptual model reflecting the current state of research in orthodontic compliance. Appliance wear is determined by treatment-related factors such as regimen and perceived comfort, as well as by external factors such as patient personality and parental attitudes. Patient attitudes are the critical link between these influences. In the focus of this article are the patient's experiences and perceptions of treatment and the way they are affected by appliance and prescribed wear. Furthermore, possible measures to enhance compliance are highlighted.

Child

A "chemical" concept for the therapy of glyoxylate-induced oxalurias (1).

Glyoxylic acid is the toxic principle of acquired and inherited oxalurias. A "chemical", not enzyme-mediated detoxication concept for the trapping of this aldehyde is described, based on a spontaneous formation of alkaloid-type heterocycles by reaction with biogenic amines or amino acids. 5,5-Dimethylthiazolidine-2(R,S)-4(S)-dicarboxylic acid, prepared by the condensation of D(-)-penicillamine with glyoxylic acid, was found to be formed quickly in vitro, to be stable in vivo and of good physiological compatibility. Renal elimination of the unchanged thiazolidine occurs mainly within 24 h, after administration of its calcium salt to NMRI-mice. Recovery up to 85% of the applied dose was quantitatively monitored by HPLC after derivatization to the corresponding fluorescent dansyl compound, which was unequivocally identified by MS analysis after isolation from mice urine.

Animals

Validation of two in vitro test systems for estrogenic activities with zearalenone, phytoestrogens and cereal extracts.

In order to establish alternatives to the frequently used uterotropic assay with mice, defined estrogen-sensitive cell lines (MCF-7 cells and LeC-9 cells) were used to determine the estrogenic activities of purified compounds of vegetable origin (myco- and phytoestrogens) and zearalenone-contaminated forage cereals (wheat, barley and oats). In MCF-7 cells, a human breast cancer cell line, the induction of an estrogen-specific exoprotein served as a parameter of estrogenic activities. LeC-9 cells represent a genetically transformed cell clone derived from mouse L-cells. Here, hormone-like activities were measured by the expression of the bacterial chloramphenicol acetyltransferase (CAT) gene under the control of an estrogen-responsive element. Toxic effects affecting cell viability were monitored in this system by the expression of a second reporter gene (the bacterial beta-galactosidase gene controlled by the constitutive human beta-actin promoter). Relative estrogenic activities of myco- and phytoestrogens determined with both systems are concomitant, but higher as compared to the uterotropic assay with mice.

Animals

[The potentials and limits of blood-flow quantification in the peripheral arteries with MRT using a phase-mapping procedure].

MRT is able to demonstrate arteries while MR angiography can quantify blood flow by a noninvasive method. In the present paper blood flow measurements were carried out in four selected cases on the basis of phase mapping. In 3 patients with lesions in the pelvis or thigh, angiography was performed in order to localise the stenosis or occlusion and this was followed by quantitative blood flow measurements. The results showed that angiography may not always provide all necessary information concerning a haemodynamically significant stenosis. The method may also be used for quantifying blood flow in the renal arteries and that it has significant advantages over the colour Doppler method.

Aorta, Abdominal

Magnetocardiographic non-invasive localization of accessory pathways in the Wolff-Parkinson-White syndrome by a multichannel system.

Electrical activity can be localized by magnetocardiography (MCG) non-invasively. In this study a 37-SQUID (Super Conducting Quantum Interference Device) sensor multi-channel system (KRENIKON) was used to assess the potential of magnetocardiography to localize accessory pathways with a multichannel system. Seven WPW patients were studied by means of magnetocardiography. Prior to the MCG recordings, the site of the accessory pathway had been determined in all patients by invasive catheter mapping. MR images of the heart were used for anatomical correlation. The magnetocardiographic localization of the accessory pathway corresponded with catheter mapping within 2.1 cm on average (total range: 0-5 cm). This is thus, a promising new method for non-invasive localization of accessory pathways in WPW patients.

Adult

Human papillomavirus in cervix carcinoma and condylomata acuminata--identification of HPV-DNA by improved dot-blot-hybridization.

Using the benzoylated naphthoylated DEAE cellulose method (BND-method) we have designed a more efficient approach for the detection of human papillomavirus-DNA (HPV-DNA) via dot-blot and hybridization. Biopsy material from anogenital warts (40 patients), invasive carcinoma uteri (12 patients) and normal controls (20 patients) were studied for the presence of HPV-DNA. Phenol extracted DNA from representative lesions was loaded onto a pretreated nitrocellulose filter, was incubated under stringent conditions with 32-P-dCTP labelled HPV-DNA and exposed to a Kodak X-OMAT film. DNA of HPV types 11, 16, 18 were cloned into plasmid vectors. The common, time-consuming caesium-chloride density-gradient centrifugation used for purification of plasmid DNA (20-36 h), was substituted by the BND-method (15 min). Complete HPV genomes were excised using the restriction endonucleases Eco RI and Bam HI. The HPV-DNA fragments obtained were then electroeluted using the 'Bio-Trap' method and subsequently labelled with 32P-dCTP by nick translation. Without resorting to more complex and sensitive technology, such as the polymerase chain reaction, efficiency of specific analysis of large numbers of cervical samples and condylomata was achieved without loss of accuracy or increased costs. The time required for HPV identification from biopsy or sample receipt was shortened considerably (approximately 50%).

Blotting, Southern

Biomagnetic multi-channel systems. Principles and application in cardiology.

The non-invasive measurement of the extremely weak magnetic fields generated by heart and brain is motivated by the possibility of obtaining quantitative diagnostic information about electric function. Magnetic signals (MCG, MEG) are significantly less influenced by body tissue than the corresponding electric signals (ECG, EEG). Measurement of biomagnetic signals is performed by superconducting sensors, consisting of pickup coils and SQUIDs (superconducting quantum interference device) operating in liquid Helium. For clinical investigations a biomagnetic multi-channel system (KRENIKONR) has been designed. It uses a flat array of 37 magnetic field sensors and is operated inside a shielded room. Evaluation of biomagnetic signals by use of simple source and body models and in combination with anatomical data from 3D MR- or CT-images yields sequences of locations of electrical function with a spatial resolution of some millimeters and a time resolution better than one millisecond. More than three years of clinical studies have demonstrated the value of the method primarily in cases with localized functional pathologies. In cardiology this is pathologies of the cardiac conductive pathway, ectopies, and arrhythmias. Validation has been performed by catheter stimulation in volunteers, and by catheter mapping and nuclear medical methods in patients. Extension of modelling and evaluation to cases with distributed activity, e.g. ventricular excitation, is under investigation.

Electromagnetic Fields

Differential exercise effects of captopril and nadolol in patients with essential hypertension.

In a crossover study, 12 patients with mild to moderate hypertension were given placebo, captopril (12.5 to 50 mg three times a day), and nadolol (20 to 160 mg once a day) to control the resting diastolic blood pressure to a nearly identical degree (p less than 0.0001) (106.1 +/- 4 placebo, 89.6 +/- 8 captopril, 89.8 +/- 7 nadolol). Both drugs lowered (p less than 0.0004) systolic and diastolic blood pressure at rest and during exercise. However, systolic blood pressure lowering during exercise was more pronounced (p less than 0.05) with nadolol than with captopril (difference of 6 mmHg, 16 mmHg, and 21 mmHg at 5.0, 7.0, and 9.0 metabolic equivalents (METS) respectively). Heart rate was lower (p less than 0.05) at rest and during exercise with nadolol as compared with placebo and with captopril. These data imply different mechanisms of action of the two drugs at rest and during exercise and may help in selection of drug therapy in special patient subsets.

Adult

Bacterial meningitis in children: pathophysiology and treatment.

Recent studies of the pathophysiology of bacterial meningitis have suggested that the development of neuronal injury is related to the release of vasoactive substances or alteration of blood-brain barrier permeability. Cerebral edema, increased intracranial pressure (ICP), systemic hypotension, decreased cerebral perfusion pressure, vascular inflammation, thrombosis, and a variety of other vascular changes may result in global or regional reductions in cerebral blood flow (CBF), which contribute to this insult. Approximately one-third of infants and children with bacterial meningitis will have markedly reduced CBF, and even in those children with normal total flow, regional hypoperfusion is common. Reduced CBF is associated with cerebral edema and a poor prognosis. A poor prognosis also is associated with reduced cerebral perfusion pressure. This occurs early in the course of meningitis and is primarily due to increased ICP rather than systemic hypotension. Autoregulation is preserved, suggesting that local ischemic tissue injury is more related to factors such as regional edema formation, focal vascular pathology, or specific intrinsic flow/metabolic abnormalities than to a reduction in systemic blood pressure. In contrast with other acute CNS insults, CBF/PCO2 reactivity is well preserved in many patients with meningitis; this raises the possibility that hyperventilation may cause further ischemic injury in those patients with marginal CBF. Although it is still unclear that treatment of increased ICP will affect outcome, we propose a treatment paradigm based on the results of neuroimaging studies and ICP measurements.

Animals

RNA polymerase chain reaction detects different levels of four alternatively spliced WT1 transcripts in Wilms' tumors.

A Wilms' tumor susceptibility gene (WT1) localized to 11p13 was recently isolated and shown to be altered in some sporadic Wilms' tumors. This gene encodes a DNA-binding protein with four zinc fingers (ZFs) in the carboxy-terminal region and a glutamine/proline (Gln/Pro)-rich domain near the 5' end. Two alternative splice sites were described, splice I in the Gln/Pro-rich domain (51 bp) and splice II between ZFs 3 and 4 (9 bp). Using RNA polymerase chain reaction (PCR) we show that Wilms' tumors contain all four possible transcripts, which are also identified in normal adult and embryonic kidney cells. The transcripts containing the 9-bp ZF insert were always predominant in tumors and normal cells. The presence of all four WT1 transcripts in tumors and expressing tissues suggests that each encoded protein isoform has an important role for the function of the WT1 gene.

Adult

[The use of the T-Scan system in occlusal diagnosis].

The present study examines the T-Scan reproduction system used in occlusal diagnosis. The system represents a major technical innovation in functional diagnostics. Nevertheless, various aspects of it still require improvement. Amplifying or confirming the results of previous studies, the following observations are intended to indicate how the system might be improved, and how it can be reliably used at present: The reproduction afforded by the sensor as situated in the mouth is insufficient. Exact reproduction of the topography of the occlusal contacts is not possible. Reproducibility of the temporal sequence of the contacts is slight. The registering of dental functional movements can give rise to errors of interpretation. Threshold values for the registration of contact points in the system's pressure mode are uneven. The relative reproduction of different impressions is unreliable. Since in the system's pressure-mode early contacts cannot be distinguished from strong physiological contacts, in clinical practice the former must first be identified using the time-mode.

Bite Force

Some psychological reactions of rape victims.

This article delineates the psychological reactions of rape victims from a psychodynamic vantage point. Rape, an act of violence, results in psychic trauma. The authors attempt an understanding of the psychological sequelae of rape.

Adaptation, Psychological