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Biomedical subjects

H Köhler

Publications and source records attributed to H Köhler.

At least 397 records · Page 22Linked to original sources
PubMed1981

Refractory period, sensory conduction velocity and visual evoked potentials before and after haemodialysis.

In 18 patients suffering from chronic renal failure (being haemodialysed three times weekly for 22.2 +/- 27.9 months), sensory conduction velocity and relative refractory period of the sural nerve were estimated immediately before and after dialysis. Before haemodialysis all but one patient had conduction velocities within the normal range (x +/- 2 SD), but 50% had prolonged refractory periods. After dialysis the refractory period decreased to become normal in all but one patient. Visual evoked potential latencies showed no systematic alterations. A membrane abnormality due to uraemic poisoning is assumed to cause the reversible prolongation of the refractory period.

Adult↗
PubMed1981

[Chronic Meningococcemia--case report and pathogenetic discussions (author's transl)].

The clinical course of chronic meningococcemia in an alcoholic patient is described. Serum IgG-, IgM- and IgA- antibody titers were followed by indirect immunofluorescence using the homologous bacterial isolate as antigen. The patients serum titers were compared with those obtained from other patients with either persistent meningococcemia or meningitis. The data revealed that antibody titers rose in both cases. The yet unexplained finding that the homologous bacterial strain persists in the bloodstream though high antibody titers were detected is discussed.

Alcoholism↗
PubMed1981

[The electrophoresis mobility test (EMT) in the immunologic after care of patients with kidney transplantations].

Of 80 recipients of kidney transplants 46 patients could after operation immunologically be controlled by means of the electrophoresis mobility test. Here a good correlation to the clinically observed or not established immune responses was shown. The method seems to be suitable for a postoperative immunological control, needs, however, a testing in a great number of patients.

Erythrocytes↗
PubMed1981

Immune response to phosphorylcholine. VIII. The response CBA/N mice to PC-LPS.

CBA/N mice and F1 crosses of CBA/N X BALB/c with the CBA/N phenotype respond to immunization with PC-LPS with a PC-specific and an anti-bridge antibody production. The PC-specific response in defective CBA/N and NBF1 is devoid of the IgG3 subclass and is not T15 idiotype dominant, whereas normal BALB/c and nondefective NBF1 mice express the T15 dominantly in their anti-PC-LPS response. By the criteria of responsiveness to PC-LPS only and the absence of dominant T15 expression, the precursors in defective NBF1 mice for TI-1 antigen PC-LPS can be characterized as being immature B cells similar to those found in neonatal livers of normal BALB/c or in spleens of chronically idiotype suppressed BALB/c mice. This analogy suggests that the developmental defect in CBA/N mice becomes active during the maturation process before selection for clonal dominance occurs and specialization of precursors for the preferred expression of the IgG3 subclass is completed. Alterations in the T cell compartment may contribute to the immature nature of B cells in the sex-linked immunodeficiency of CBA/N mice.

Aging↗
PubMed1981

[Preoperative renal artery embolization of malignant tumors in external patients].

In 53 external patients with extensive malignant renal tumours before nephrectomy the renal artery was closed centrally by radioopaque ivalonchips. 46 arteries were completely obturated, in 7 cases the embolization was incomplete. This method of embolization is indicated preoperatively because there are some advantages concerning technique of operation. In or ivalon-material there was only one complication without clinical symptoms. The occurring ischemic pain was controllable by medicaments and eased off within some hours. Directly after transcatheter occlusion the patients can be transported back under first aid conditions in hospital where will be nephrectomy carried out.

Adenocarcinoma↗
PubMed1980

Late clonal selection and expansion of the TEPC-15 germ-line specificity.

The maturation of the antibody response to phosphorylcholine (PC) in neonatal BALB/c mice was studied. A T cell-independent class 1 1 PC-antigen, 3-(p-azophenyl phosphorylcholine)-N-acetyl-L-tyrosylglycylglycine lipopolysaccharide, was synthesized and used to immunize neonatal mice of different ages. The earliest anti-PC hemolytic plaque-forming response could be induced in 1-d-old neonates. Idiotype analysis on these early anti-PC antibodies showed that the response was not TEPC-15 dominant although TEPC-15-positive plaque-forming cells were detected. However, idiotype analysis of the anti-PC-LPS response in 7 d or older animals indicated that clonal dominance had been established. Similar results were obtained in splenic fragment culture with cells from neonatal livers and spleens. PC-specific precursors were detected in the liver of 1-d-old neonates, whereas the spleen of those animals contained no precursors for PC. Precursors for PC residing in the neonatal liver are not TEPC-15 dominant, whereas the splenic PC precursors of 5- to 6-day-old animals express the TEPC-15 idiotype dominatly. These findings demonstrate that during ontogeny PC-specific B cells appear before the TEPC-15 clone becomes dominant. Thus clonal dominance in the adult anti-PC response and late acquisition of the TEPC-15 specificity during ontogeny do not signify a particularly unique or direct relationship to the expression of genes encoded in the germline.

Animals↗
PubMed1980

An immunologic network.

The immune system is a complex network of molecules and cells specifically connected by the complementarity of receptors for antigen and receptors for receptors. The network includes multiple positive- and negative-feedback loops, which modulate the type, magnitude, and duration of responses. The great challenge is to devise ways to manipulate the system specifically to induce effective autoimmunity to cancer, to prevent allograft rejection, and to turn off undesirable responses in allergies and autoimmune diseases. Recognition of the immune system as a network helps to explain why these objectives are so difficult and why manipulation of multiple components to achieve desired regulation may be required. But presumably manipulation must be focused on connectivity between receptor for epitope and receptor for receptor to achieve a high degree of specific regulation.

Animals↗
PubMed1980

Elimination of guanfacine in patients with normal and impaired renal function.

1. Total body clearance and renal clearance after single intravenous doses of guanfacine were 360 +/- 262 (mean +/- s.d.) and 233 +/- 245 ml/min, respectively, in patients with normal renal function (glomerular filtration rate (GFR) > 90 ml/min), 308 +/- 274 and 34 +/- 22 ml/min, respectively, in patients with moderately impaired renal function (GFR 30-10 ml/min), and 257 +/- 187 and 18 +/- 15 ml/min, respectively, in preuremic patients (GFR < 10 ml/min). 2. The cumulative urinary excretion up to 48 h after a single intravenous injection of guanfacine was 57.0 +/- 32.0% in patients with GFR > 90 ml/min, 14.0 +/- 9.0% in patients with GFR 30-10 ml/min and 7.5 +/- 2.4% in preuremic patients. 3. In normal as well as impaired renal function the elimination rate constant of guanfacine was 0.05 h-1, which corresponds to an elimination half-life of 14 h, independent of renal function. 4. These results suggest that non-renal elimination of guanfacine plays an important role in patients with renal failure. 5. Intestinal absorption of guanfacine was calculated to be 59 +/- 19% in patients with GFR > 90 ml/min, to 68 +/- 16% in patients with GFR 30-10 ml/min, and to 73 +/- 36% in preuremic patients.

Absorption↗
PubMed1980

Immune response to phosphorylcholine. VII. Functional evidence for three separate B cell subpopulations responding to TI and TD PC-antigens.

A T-independent PC antigen, the C-polysaccharide, was used to induce a primary response to PC in splenic foci containing precursors taken from normal, unprimed BALB/c mice. The precursor frequency for the TI response was compared with the frequency for a T-dependent PC antigen, PPC-TGG-Hy. Idiotype analysis of the precursors for TD and TI responses indicate that the TD responses are more diverse with respect to clonal dominance of idiotype, TEPC-15, than that of TI responses. If splenic fragments were doubly immunized with both TI and TD antigens, the combined PC-specific precursor frequency was superadditive. TD-antigen-induced responses were found resistant to tolerogen and anti-idiotype suppression, whereas TI responses were extremely sensitive to both manipulations. Since under limiting dilution conditions precursors sort out independently, the superadditive response seen in dual immunized fragments can only be interpreted as evidence for an additional subpopulation of B cells that responds to the combined signals of TD and TI antigens. This postulated third B cell population is also extremely sensitive to tolerogen and anti-idiotype suppression.

Animals↗
PubMed1980

Maturation of B-cell clones.

The maturation of B-cells was investigated in adoptive transfers and splenic foci. Anti-idiotypic antigens were used to identify clones responding to PC and dextran. A distinct temporal hierarchy of responsiveness could be observed in which the anti-TNP response appears first, followed by anti-dextran and anti-PC. Tolerance induction and anti-idiotype suppression were used as markers for maturing B-cells responding in splenic foci. A differential susceptibility to these manipulations establishes two types of progenitor cells. A scheme for the maturational steps of B-cells is proposed.

Animals↗
PubMed1980

Mechanism of neonatal idiotype suppression. II. Alterations in the T cell compartment suppress the maturation of B cell precursors.

The cellular mechanism in neonatally suppressed BALB/c mice, which maintains the chronic suppressed state of the TEPC-15 idiotype in the antibody response to phosphorylcholine (PC), was investigated. Cells taken from these suppressed mice cannot transfer suppression to adult BALB/c or affect the in vitro response to PC of adult BALB/c spleen cells. However, spleen cells or T cells from neonatally suppressed mice given to neonatal animals induce chronic suppression of the TEPC-15 idiotype in the anti-PC response. Co-transfer of T cells from neonatally suppressed cells with normal T cells prevented the induction of suppression in neonates. Transfer of T cells from normal or keyhole limpet hemocyanin-primed BALB/c increased the expression of TEPC-15 idiotype in chronically suppressed mice, whereas T cells from neonatally suppressed were ineffective. These findings show that T cells in neonatally suppressed mice can affect the development of immature but not mature cells. The restoration of TEPC-15 expression in neonatally suppressed animals by normal T cells and the failure to induce suppression in neonates by co-transfers of T cells from normal and chronically suppressed mice demonstrate the profound role of an altered T cell compartment in sustaining chronic idiotype suppression.

Animals↗
PubMed1980

Mechanism of neonatal idiotype suppression. I. State of the suppressed B cells.

Neonatal BALB/c mice, given small amounts of an anti-idiotype serum directed against the TEPC-15 idiotype, are chronically unresponsive to immunization with PC antigens. These mice recover from suppression slowly over a period of 10 mo, and their response is not of TEPC-15 idiotype. However, the PC-specific precursors, as analyzed by the splenic fragment culture technique, in 8-mo-old suppressed mice are normal with respect to their frequency and idiotype dominance. Furthermore, the PC-precursors in neonatally suppressed BALB/c are sensitive to tolerance induction, as are precursors from neonatal liver and spleen cells. When chronic suppressed mice are immunized with a novel TI-1 antigen, PC-LPS, shown to stimulate immature PC-specific precursors, their response to PC is 80% of TEPC-15 idiotype, whereas their response to a TI-2 PC antigen and to a TD PC antigen is not TEPC-15 dominant. These results indicate that the TEPC-15 positive B cells in neonatally idiotype suppressed mice are in a state of immaturity that resembles the developmental characteristics of normal neonatal BALB/c mice.

Animals↗