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H Köhler

Publications and source records attributed to H Köhler.

At least 271 records · Page 15Linked to original sources
PubMed1989

Perturbation of the idiotypic network. II. Transfer of suppression to neonatal mice.

The cellular mechanisms which are responsible for idiotype perturbation induced by repeated stimulation with either allogeneic mixed lymphocyte culture-generated syngeneic blasts or allogeneically stimulated syngeneic spleen cells were investigated as described in the preceding article. Using the splenic fragment culture system, the precursor frequencies of T and B cells for anti-phosphorylcholine (PC) antibodies and T15 idiotypic antibodies were determined in allogeneically challenged mice. Adoptive transfers of T cells to neonatal BALB/c mice induced suppression of the T15+ anti-PC responses. In addition, the effect of immunization with internal image-bearing anti-idiotopes on the level of anti-PC antibodies and T15 idiotype was determined. Results from this study demonstrated (i) a decrease in the precursor frequency in the PC-specific and idiotype-specific B cell repertoire; (ii) a decrease in the precursor frequency of T helper cells, which recognize idiotypes and anti-idiotypes; (iii) the possibility to transfer T15 suppression to neonatal mice; and (iv) the possibility to restore T15 dominance by anti-idiotypic antibody immunization. These data indicate that both the T and B compartments are involved in the maintenance of suppression induced by repeated exposure to alloantigen-sensitized syngeneic cells. Collectively these findings show that a nonspecific general suppression induced by allohyperimmunization can perturb the T15+ anti-PC response.

Animals↗
PubMed1989

Characterization of "regulatory" idiotope-specific T cell clones to a monoclonal anti-idiotypic antibody mimicking a tumor-associated antigen (TAA).

As reported previously, 3A4 is a paratope-specific anti-idiotypic mAb and induces cellular and humoral anti-tumor-associated Ag (TAA) responses. In this study, the specificity, MHC restriction and Ag processing requirement of Th cell lines and clones were determined that recognize an idiotypic determinant (Id) on 3A4. The anti-Id-3A4 is part of a tumor-associated idiotypic network which is involved in the regulation of the immunity against the DBA/2 L1210/GZL tumor. These 3A4-Id-specific T cell clones are phenotypically Th cells and recognize Id in the context of MHC class II molecules under MHC restriction. Moreover, the recognition of Id by these T cell clones is chloroquine sensitive, suggesting that they recognize processed Id. However, the 3A4-Id-specific T cell clones respond only to 3A4 and not to TAA. Because these clones do not recognize TAA, their biologic role in antitumor immunity could be as regulatory T cells involved in the idiotypic network regulation.

Animals↗
PubMed1989

[The importance of the trace element selenium in internal diseases].

Issuing from the existence of selenium and its interactions with other elements its essentiality in biochemical processes of man was explained. In correspondence with other research teams also own results speak for a relative selenium deficiency in the Middle-European region. Alterations of the cell integrity caused by selenium deficiency may play a role in the etiopathogenesis and perpetuation of chronic cardiovascular diseases as well as of disturbances of the immunoregulation. Recent epidemiological studies and clinical experimental investigations show potential tendencies for prophylaxis and therapy of diseases which are remarkable in health policy.

Cardiovascular Diseases↗
PubMed1989

Low-dose interleukin-2 induces systemic immune responses against HBsAg in immunodeficient non-responders to hepatitis B vaccination.

A metabolic monocyte defect appears to correlate with non-responsiveness to hepatitis B vaccine in many patients on haemodialysis. This defect prevents production of interleukin-2 during T-cell activation after antigen contact. Receptors for interleukin-2 are, however, expressed in greater numbers than in healthy subjects or uraemic responders to hepatitis B vaccination. In this study, ten uraemic patients, previous non-responders to vaccination against hepatitis B, were revaccinated with the same vaccine combined with one intramuscular injection (2.5 x 10(5) U) of natural human interleukin-2. Systemic production of antibodies against hepatitis B surface antigen was initiated in those immunodeficient patients whose cellular interleukin-2 receptor levels were found to be enhanced.

Adult↗
PubMed1989

The perfused porcine pancreas as a model for testing organ protective solutions.

The present study was designed to establish an in vitro perfused porcine pancreas preparation as a model for testing the effect of organ protective solutions on stimulated pancreatic endocrine and exocrine secretion. The pancreas was prepared and perfused for 10 min with Euro Collins solution, thereafter it was stored in the cold (4 degrees C) for various times. After 3-h and 6-h ischemia pancreatic insulin release in response to glucose was not significantly affected. After 12-h ischemia reduced pancreatic insulin secretin, increased perfusion pressure, and increased amylase and lipase release indicated pancreatic damage. Complete pancreatic dysfunction was seen after 24-h and 48-h ischemia with massive increase in perfusion pressure and low insulin secretion which did not follow a glucose-dependent release pattern, while amylase and lipase concentrations in the perfusion medium increased. Stimulated exocrine pancreatic secretion was significantly decreased already after 3-h ischemia and completely lost after 12 h.

Amylases↗
PubMed1989

Secretory immunoglobulin A in urinary tract infection, chronic glomerulonephritis, and renal transplantation.

An enzyme-linked immunoassay (ELISA) for the quantitation of secretory IgA (S-IgA) in the urine is described. The assay is sensitive (linear down to 0.02 microgram/ml), specific, and reproducible (intraassay variation 7.8%, interassay variation 18.9%). The assay was used to determine the urinary excretion rates of S-IgA in patients with bladder catheter (n = 12), cystotomy and urinary tract infection (n = 13), urosepsis (n = 5), chronic glomerulonephritis, including IgA-nephritis (n = 31), in renal allograft recipients (n = 30), and in healthy controls (n = 46). An elevated S-IgA urinary excretion (P less than 0.01) was found in all patient groups studied. The highest values were observed in urosepsis. No significant differences between S-IgA levels in IgA-nephritis and other forms of chronic glomerulonephritis were detected. The elevated S-IgA excretion in renal allograft recipients indicates that immunosuppressive therapy does not influence the local S-IgA production in the urinary tract. The susceptibility of these patients to urinary tract infections is therefore not due to a S-IgA deficiency.

Diuresis↗
PubMed1989

Revised immune network concepts.

The idiotype network concept needs to be revised in order to be in agreement with current data on protein/protein interactions, with the phenomenon of T and B cell recognition of idiotopes, and with the failure of certain anti-idiotypes to stimulate a given immune response. It is proposed that the distinction among Ab2 alpha, beta, and gamma is abandoned, as well as the concept of an internal image idiotope which mimics the three-dimensional shape of nominal antigen. In place of these definitions, the concept of "network antigen" is introduced. Network antigens are potentially the entire repertoire of anti-idiotypes. However, their biological effectiveness is controlled and established by two factors: (i) the affinity to the idiotype Ig receptor; and (ii) the preexisting regulatory network segment that controls the outcome of immune stimulation or suppression. Screening for effective idiotype therapeutic agents has to be done with panels of anti-idiotype and idiotype antibodies in order to establish correlations between idiotope expression and disease progression. Recognizing the importance of network segments will be the first step in the direction toward a rational design of idiotype-based therapies.

Humans↗
PubMed1989

The influence of the duodenal passage on postprandial neurotensin release in dogs.

All types of gastric resections induce an abnormal release of gastrointestinal hormones. The missing duodenal passage seems to be the most important factor for these disturbances. In the present study we have examined the effect of exclusion and restoration of the duodenal passage on the postprandial release of neurotensin in dogs. After feeding a standard canned dog meal, exclusion of the duodenal passage by a Billroth-II-resection caused a significant increase in postprandial neurotensin release compared to the control group (peak levels 52 +/- 5.6 to 29 +/- 6 pg/ml preoperatively, integrated output 2132 +/- 228 to 3604 +/- 213 pg/ml x 150 min. p less than 0.05). Reconstruction of the duodenal passage by the Biebl-Henly-Soupault-procedure tended the elevated neurotensin levels towards normal (peak levels 36 +/- 4.8 pg/ml, integrated output 2448 +/- 236 pg/ml x 150 min., p less than 0.05). From our data we conclude that changes in intestinal transit time are responsible for the pathological increase in neurotensin release after exclusion of the duodenal passage.

Animals↗
PubMed1989

The biological relevance of N-terminal neurotensin fragments in the regulation of exocrine pancreas secretion.

Stimulation of the exocrine pancreas is one of the biological effects attributed to the tridecapeptide neurotensin (NT). Only the C-terminal 8-13 fragment with its extremely short plasma half-life in the peripheral circulation was considered to be necessary for biological activity. The N-terminal fragments that are detectable in peripheral blood in much greater concentrations were considered to be of no importance. In order to elucidate the biological relevance of these N-terminal fragments, five dogs were infused with neurotensin at a rate (50 pmol/kg/h) that had been determined to give physiological plasma concentrations. Pancreatic secretions were collected from previously implanted modified Herrera pouches. The effects of the N-terminal fragments NT 1-8 and NT 1-11 on the exocrine pancreas secretion were tested in the same way. It was possible for the first time to demonstrate a biological effect of the N-terminal fragments found in the postprandial circulation in vivo. The plasma concentrations determined by radioimmunoassay remained within the physiological range (less than 40 pg/ml). These N-terminal neurotensin fragments may therefore participate in the hormonal regulation of the exocrine pancreas secretion.

Animals↗
PubMed1989

[Stapler-dependent surgical procedures in the colorectal area].

Since its introduction, stapling has gained considerable interest in colon surgery. The double stapling technique is a further development. From 1984 to 1989, 110 low anterior resections were performed at the Department of General Surgery, University of Goettingen. In 73 patients anastomosis was performed by double stapling; in 37 cases the EEA stapler was used. The double stapling group had an insufficiency rate of 2.7% compared with 5.4% in the EEA group. Another useful indication for stapler techniques is a reconstructive operation according to the Hartmann procedure. In none of 43 such interventions between 1983 and 1988 was insufficiency of the anastomosis seen. Another useful employment of staplers is construction of colonic reservoirs after proctocolectomy.

Anastomosis, Surgical↗
PubMed1989

[Recommendations for the therapy of atypical immunization courses and complications of BCG vaccination (Position: April, 1988)].

After introduction of the "direct" BCG-vaccination of the 16 years old youngsters in 1981 a small increase of atypical reactions and complications of the vaccination was probable. References and experiences about different therapy methods of these atypical reactions and complications gave rise to recommend uniform guide-lines for definition, diagnostic and therapy.

Adolescent↗
PubMed1989

Incidence and frequency or complications and management of Meckel's diverticulum.

During the last 27 years, 84 patients with Meckel's diverticulum (MD) have undergone resection at our institution (incidental findings, n = 50; MD with complications, n = 34). The most frequent complications of MD were obstruction and diverticulitis. Analysis of records of patients revealed that MD is a rare intraoperative finding. The calculated incidence was 2.4 per cent, and the ratio of diverticulectomy to appendectomy was 1:55. A preoperative diagnosis of MD was rare (4 per cent). Only in those patients with hemorrhage were diagnostic procedures (angiography, scintigraphy and roentgenography) useful. Ectopic tissues occurred in 23 per cent of all patients and were observed more often in patients with complications of MD. There was a correlation between hemorrhage and gastric heterotopic tissue. Another correlation was found between invagination and pancreatic tissue as well as diverticulitis. Postoperative adhesions causing ileus was the main complication found after resection for MD (8 per cent), whereas no other severe complications were observed (no insufficiency). There was no death as a result of resection. Because of the low rate of postoperative complications and the latent risk of complications arising sometime during life in sporadic episodes, a prophylactic resection is indicated but is often performed too late because the primary endangered group for complications is children who are less than two years of age. Predominantly in those with hemorrhage, the base of the diverticulum should be carefully checked for heterotopic tissue to prevent further complications.

Adolescent↗
PubMed1989

[Hemodynamic characteristics of necrotizing pancreatitis].

Seventy-one patients with necrotizing pancreatitis in stages II and III were treated at the surgical intensive care unit in the authors' hospital, between 1982 and 1986. Pathological courses in 23 patients were so severe that a pulmonary catheter had to be applied to monitor haemodynamic changes. Seventeen of these 23 patients died (73.9 per cent), while six survived. The gravest difference between these two groups was relating to vasculopulmonary resistance, which went up strongly in the first group (428 +/- 19 dyn X sec X cm-5) and stayed moderate in the second (201 +/- 13 dyn X sec X cm-5). The left-ventricular stroke work index in the first group was lower with significance than that in the second, the values being 33.4 +/- 2 g X m/m2 versus 44 +/- 4.6 g X m/m2.

Acute Disease↗