Search PubMed⌕ Search

Biomedical subjects

W Kruis

Publications and source records attributed to W Kruis.

At least 55 records · Page 3Linked to original sources
PubMed1999

Modulation of base hydroxylation by bile acids and salicylates in a model of human colonic mucosal DNA: putative implications in colonic cancer.

Bile acids are believed to be involved in the formation of colonic cancer, and 5-aminosalicylic acid and other salicylates may have a protective role. The precise mechanisms of both actions are not known, but modifications (stimulation or inhibition) of basal or oxygen-radical induced DNA base hydroxylation as potential early events in tumor formation by these compounds may be involved in such actions. We, therefore, investigated whether: (1) bile acids in concentrations as they occur systemically or intraluminally are able to enhance basal or OH*-radical-stimulated base hydroxylation in DNA from calf thymus; (2) 5-aminosalicylic acid, its main intestinal metabolite N-acetyl-aminosalicylic acid and salicylate, the main aspirin metabolite, are able to inhibit this hydroxylation; and (3) DNA from calf thymus can be used as a model by comparing its base composition and hydroxylation with DNA from normal human colonic mucosa. We found an enhancement of the OH*-radical-induced DNA hydroxylation especially 8-OH adenine with 214.0%. On the other hand 5-ASA, N-acetyl-ASA, and salicylate showed a concentration-dependent inhibition of OH*-stimulated hydroxylation with IC50 between 0.04 +/- 0.01 mM (X +/- SD) and 1.3 +/- 0.1 mM. No effects were observed on basal hydroxylation. Electron spin resonance spectroscopy studies showed reduction of the corresponding base signals pointing to a scavenger mechanism. In DNA isolated from normal human colonic mucosa (N = 7) a similar base distribution was found as in calf thymus; hydroxylation was < or = 1.0% in both systems. From our results we conclude that DNA from calf thymus may serve as a model for human colonic mucosal DNA and that one of the carcinogenic actions of bile acids may be enhancement of oxygen-radical-induced DNA base hydroxylation, especially 8-OH adenine. The absence of effects under unstimulated conditions supports their role as cocarcinogens. The concentration-dependent inhibition of OH*-stimulated DNA hydroxylation by 5-ASA, salicylate, and N-acetyl-ASA may be a possible mechanism of chemoprevention.

Animals↗
PubMed1999

A chimeric receptor that selectively targets membrane-bound carcinoembryonic antigen (mCEA) in the presence of soluble CEA.

Chimeric T cell receptors with specificity for tumor-associated antigens are successfully used to target T cells to tumor cells. The efficacy of this approach, however, is reduced by soluble antigen that is frequently present in high serum concentrations. To overcome this situation, we constructed an anti-CEA chimeric receptor whose extracellular moiety is composed of a humanized single chain antibody fragment (scFv) derived from the anti-CEA mAb BW431/26 and the CH2/CH3 constant domains of human IgG. The intracellular moiety consists of the gamma-signaling chain of the human Fc epsilon RI receptor constituting a completely humanized chimeric receptor. After transfection, the humBW431/26 scFv-CH2CH3-gamma receptor is expressed as a homodimer on the surface of MD45 T cells. Co-incubation with CEA+ tumor cells specifically activates grafted MD45 T cells indicated by IL-2 secretion and cytolytic activity against CEA+ tumor cells. Notably, the efficacy of receptor-mediated activation is not affected by soluble CEA up to 25 micrograms/ml demonstrating the usefulness of this chimeric receptor for specific cellular activation by membrane-bound CEA even in the presence of high concentrations of CEA, as found in patients during progression of the disease.

Carcinoembryonic Antigen↗
PubMed1999

Arterial oxygen desaturation during endoscopic ultrasonography combined with gastroscopy: a safety evaluation in out-patients.

BACKGROUND AND STUDY AIMS: Data concerning potential clinically relevant arterial oxygen desaturation (SaO2 <90.0 %) during endoscopic ultrasonography (EUS) combined with a prior conventional gastroscopy are not available, but are nevertheless important in view of the increasing numbers of examinations and relevant safety standards. We therefore continuously measured SaO2 before and during the periods of gastroscopy and subsequent EUS in order to answer the question of whether EUS has additional effects on arterial oxygen desaturation. A secondary aim of the study was to define patients with particular risks for decreased SaO2. PATIENTS AND METHODS: SaO2 was continuously monitored in 96 outpatients before and during the endoscopic procedures. After sedation with midazolam, an exploratory gastroscopy was performed, followed by endoscopic ultrasonography. RESULTS: In all patients undergoing gastroscopy followed by EUS (n = 96), SaO2 values significantly decreased from 96.5 +/- 2.6 % to 92.4 +/- 4.7 % (P < 0.0001). Analysis of the time-related SaO2 courses showed that the minimal SaO2 was reached after 7.5 minutes. The SaO2 curves in patients with desaturation (n = 29) were similar to those in patients who had no desaturation, except for a significantly lower nadir (88.6 +/- 5.3 %, P< 0.0001). The SaO2 time courses in all patients showed no further decrease or a second minimum during the EUS period, as might have been expected with the insertion of a second instrument. Baseline (pre-procedure) and minimal SaO2 were significantly correlated (T(s): 0.604, P<0.038). Quantitative analysis yielded the lowest significant percentage of desaturation, with baseline SaO2 equal to or above 97.5 % (6.3 %, P< 0.038). CONCLUSIONS: EUS following an exploratory gastroscopy under mild sedation causes no additional reduction in SaO2. Patients with an initial arterial oxygen saturation equal to or above 97.5 % may have a low probability of desaturation during the combined procedure after sedation with one single midazolam dose, and are therefore unlikely to need further monitoring after an initial assessment. Patients below this limit, however, should be continuously monitored, due to the increasing probability of desaturation below this limit.

Adult↗
PubMed1998

Genetic analysis of inflammatory bowel disease in a large European cohort supports linkage to chromosomes 12 and 16.

BACKGROUND & AIMS: Inflammatory bowel disease (IBD) is a complex disorder of unknown etiology. Epidemiological investigations suggest a genetic basis for IBD. Recent genetic studies have identified several IBD linkages. The significance of these linkages will be determined by studies in large patient collections. The aim of this study was to replicate IBD linkages on chromosomes 12 and 16 in a large European cohort. METHODS: Three hundred fifty-nine affected sibling pairs from 274 kindreds were genotyped using microsatellite markers spanning chromosomes 12 and 16. Affection status of the sibling pairs was defined as Crohn's disease (CD) or ulcerative colitis (UC). RESULTS: Nonparametric statistical analyses showed linkage for both chromosomes. Two-point results for chromosome 12 peaked at D12S303 (logarithm of odds [LOD], 2.15; P = 0.003) for CD and at D12S75 (LOD, 0.92; P = 0.03) for UC. Multipoint analyses produced a peak LOD of 1.8 for CD. Chromosome 16 showed linkage for CD at marker D16S415 (LOD, 1.52; P = 0.007). Multipoint support peaked above markers D16S409 and D16S411 (LOD, 1.7). CONCLUSIONS: These data are consistent with linkage of IBD to chromosomes 12 and 16. The replication of genetic risk loci in a large independent family collection indicates important and common susceptibility genes in these regions and will facilitate identification of genes involved in IBD.

Chromosomes, Human, Pair 12↗
PubMed1998

Olsalazine versus mesalazine in the treatment of mild to moderate ulcerative colitis.

AIM: To compare the efficacy and tolerability of olsalazine sodium with enteric-coated mesalazine in inducing endoscopic remission in patients with mild to moderate active ulcerative colitis. PATIENTS AND METHODS: Patients with mild to moderate active ulcerative colitis were randomized to receive either olsalazine sodium, 3 g/day (n = 88), or mesalazine, 3 g/day (n = 80), for up to 12 weeks. RESULTS: Of the patients treated with olsalazine sodium, 52.2% achieved endoscopic remission, compared with 48.8% of patients treated with mesalazine. This difference was not significant (P = 0.67). There was a nonsignificant trend for patients with left-sided colitis or a more severe endoscopic grade to achieve remission if they were treated with olsalazine sodium than if they were treated with mesalazine. Both treatments were comparable with respect to clinical activity index and an investigator's global assessment. Seventy patients reported one or more adverse events; adverse events were seen in 45% of olsalazine sodium-treated patients and in 36% of mesalazine-treated patients. Eleven patients treated with olsalazine sodium and nine patients treated with mesalazine withdrew from the study because of adverse events. One patient treated with olsalazine sodium compared with two treated with mesalazine stopped treatment because of diarrhoea. Serious adverse events occurred in three patients treated with olsalazine sodium and in four treated with mesalazine. CONCLUSION: Therapeutic effectiveness and tolerance to the treatment did not differ between olsalazine sodium, 3 g/day, and mesalazine, 3 g/day, in inducing endoscopic remission in patients with mild to moderate active ulcerative colitis within 12 weeks of treatment.

Adult↗
PubMed1998

Chimeric anti-TAG72 receptors with immunoglobulin constant Fc domains and gamma or zeta signalling chains.

We recently described the generation and expression of a chimeric T cell receptor with specificity for the tumor antigen TAG72 consisting of the single chain antibody (scFv) B72.3-scFv and the gamma chain of the FcepsilonRI receptor. The corresponding chimeric receptor containing the zeta chain of the TCR as signalling unit is not functionally expressed reflecting that the requirements for functional expression of chimeric receptors containing the gamma signalling chain are apparently different compared to those containing the CD3zeta signalling chain of the TCR. We describe a novel set of chimeric anti-TAG72 receptors including in their extracellular moiety the constant immunoglobulin CH2/3 domains that allow stable expression of chimeric gamma as well as zeta receptors. We designed anti-TAG72 receptors that consist of a scFv fragment derived from an anti-TAG72 second generation antibody (CC49) and of the CH2/3 domains of the human IgG and intracellularily either of the zeta or gamma signalling chain. The recombinant CC49-CH2/3-zeta and CC49-CH2/3-gamma DNA, respectively, was transfected into MD45 T cells and expressed under control of the RSV LTR. Both receptors were found on the cell membrane of transfected cells as demonstrated by flow cytometry analysis using an anti-human IgG Fc antibody directed to the CH2/3 immunoglobulin domains of the chimeric receptor. Specific cross-linking of the chimeric zeta as well as the gamma receptor by antigen or anti-human Ig antibodies resulted in specific activation of transfected cells. Our results demonstrate that both the gamma chain and the zeta chain++ containing receptor are stably expressed and convert T cells to specificity for the TAG72 antigen. This receptor design will facilitate efficient generation of genetically modified peripheral T cells and may provide valuable tools for the cellular immunotherapy of TAG72+ tumors.

Animals↗
PubMed1997

Molecular biology in diagnosis and epidemiology of Helicobacter pylori: PCR for the detection and AP-PCR for characterization of patient isolates.

Infection with Helicobacter pylori causes chronic active gastritis and has been associated with gastric and duodenal ulcer disease. In biopsy samples of 110 patients with clinical symptoms of active gastritis, H. pylori was detected by means of the polymerase chain reaction (PCR), using species-specific primers defining a 858 bp DNA fragment of H. pylori urease beta-subunit. Sensitivity and specificity of the PCR was compared with culture, histology and Warthin-Starry stain (WSs), detection of H. pylori urease antibodies in serum and urease testing with the Campylobacter-like organism (CLO) test. PCR yielded specific amplification products in 53 cases, whereas culture of the organisms was positive in a subset of 50 cases. Only direct detection in histological sections of biopsy specimens had a higher sensitivity, with 65 positive samples. In contrast, the CLO test was negative in eleven culture-positive and PCR-positive cases. Significant urease antibody titres were found in 39 patients with histologically confirmed diagnosis. These results placed the sensitivity of PCR between tat of the Warthin-Starry stain (WSs) and that of culture. Therefore, PCR can be proposed as a useful rapid and time-saving technique for the detection of H.pylori in gastritis. For epidemiological purposes, fingerprinting with arbitrarily chosen primers by AP-PCR was evaluated. Strain-specific patterns with up to 13 fragments were achieved with 10-nucleotide or longer primers (21-nt) with a G + C content > or = 55%. Thirty-five of 40 strains investigated by this method were distinguishable with a single primer. These results suggest a high level of DNA sequence diversity within this species with the possibility of confirming the clonality in consecutive isolates from a single individual. Alternatively, an increased in-vivo mutation rate could be responsible for DNA divergence, resulting in specific strains for each individual patient.

Antibodies, Bacterial↗
PubMed1997

Double-blind comparison of an oral Escherichia coli preparation and mesalazine in maintaining remission of ulcerative colitis.

BACKGROUND: Aminosalicylates are used as standard treatment for maintaining remission in ulcerative colitis. As yet, there is no other existing alternative with proven efficacy. In light of the hypothesis that the intestinal environment may contribute to the pathophysiology of ulcerative colitis, a trial was conducted to test the effects of probiotic treatment with an oral preparation of non-pathogenic E. coli. METHODS: A total of 120 patients with inactive ulcerative colitis were included in a double-blind, double-dummy study comparing mesalazine 500 mg t.d.s. to an oral preparation of viable E. coli strain Nissle (Serotype 06: K5: H1) for 12 weeks with regard to their efficacy in preventing a relapse of the disease. Study objectives were to assess the equivalence of the clinical activity index (CAI) under the two treatment modalities and to compare relapse rates, relapse-free times and global assessment. RESULTS: The start and end scores of the CAI demonstrated no significant difference (P = 0.12) between the two treatment groups. Relapse rates were 11.3% under mesalazine and 16.0% under E. coli Nissle 1917 (N.S.). Life table analysis showed a relapse-free time of 103 +/- 4 days for mesalazine and 106 +/- 5 days for E. coli Nissle 1917 (N.S.). Global assessment was similar for both groups. Tolerability to the treatment was excellent and did not differ. No serious adverse events were reported. CONCLUSIONS: From the results of this preliminary study, probiotic treatment appears to offer another option for maintenance therapy of ulcerative colitis. Additional support is provided for the hypothesis of a pathophysiological role for the intestinal environment in ulcerative colitis.

Adult↗
PubMed1997

Specific activation of resting T cells against tumour cells by bispecific antibodies and CD28-mediated costimulation is accompanied by Th1 differentiation and recruitment of MHC-independent cytotoxicity.

Specific activation of resting lymphocytes for tumour targeting can be achieved by bispecific monoclonal antibodies (bi-MoAbs) with specificity for tumour antigens and T cell-activating antigens in combination with a costimulatory anti-CD28 antibody. In this study we focus on the immunomodulatory function of an anti-CD3/CA19-9 bi-MoAb in combination with a costimulatory anti-CD28 antibody which may result not only in antigen-specific, T cell-mediated tumour cell lysis but also in recruitment of other cellular effector functions. In combination with costimulatory anti-CD28 antibodies, resting peripheral lymphocytes could be activated specifically to secrete high amounts of Th1 cytokines (IL-2, interferon-gamma (IFN-gamma)) characterizing a cellular immune response. In contrast, no IL-4 and only low amounts of IL-10 could be detected. Furthermore, bi-MoAb-mediated CA19-9-specific activation of T cells was accompanied by recruitment of MHC- and CA19-9-independent cytotoxicity, as was determined by lysis of different CA19-9-cell lines. This MHC-independent cytotxicity was mediated at least in part by activated natural killer (NK) cells, as depletion of CD16+ NK cells resulted in substantial decrease of cytotoxicity against CA19-9- targets. Our results indicate that specific activation of resting T cells with CD3-associated bi-MoAbs in combination with an anti-CD28 antibody leads to a Th1 differentiation pathway and is accompanied by recruitment of MHC-independent lymphokine-activated killer (LAK) cell cytotoxicity which can possibly be directed against a heterogeneous tumour.

Antibodies, Bispecific↗
PubMed1997

T cell targeting of TAG72+ tumor cells by a chimeric receptor with antibody-like specificity for a carbohydrate epitope.

BACKGROUND & AIMS: Chimeric receptors with specificity for defined tumor antigens are valuable tools for targeting cytolytic T cells specifically to tumor cells. The aim of this study, for the situation of gastrointestinal cancer, was to investigate the generation of a chimeric T cell receptor that specifically binds the tumor antigen TAG72 (CA72-4) and transmits a signal for cellular activation. METHODS: A single-chain antibody (scFv) was derived from the monoclonal anti-TAG72 antibody B72.3 by phage display techniques (B72.3-scFv) and fused to the signaling unit of the Fc epsilon-RI receptor gamma chain, resulting in a chimeric signaling receptor, B72.3-scFv-gamma. RESULTS: The B72.3-scFv and the chimeric B72.3-scFv-gamma receptor bound specifically to the TAG72 antigen. After transfection, T cells expressing the chimeric B72.3-scFv-gamma specifically recognized TAG72 positive cells. Cross-linking of the chimeric receptor with antigen resulted in interleukin 2 release and cytolytic activity against TAG72 positive tumor cells in vitro. CONCLUSIONS: T cells equipped with the chimeric anti-TAG72 receptor can be specifically activated to target and lyse TAG72 positive gastrointestinal tumor cells.

Animals↗
PubMed1997

A prospective evaluation of the diagnostic work-up before laparoscopic cholecystectomy.

BACKGROUND AND STUDY AIMS: A prerequisite for successful laparoscopic cholecystectomy is the exclusion of potential risks such as cholangiolithiasis or anatomical malformations. As there is no general agreement regarding the appropriate preoperative diagnostic work-up, a comparative study of different diagnostic methods was carried out. PATIENTS AND METHODS: In 180 consecutive patients admitted to a community hospital for cholecystectomy due to symptomatic cholecystolithiasis, a prospective comparison was carried out of the diagnostic accuracy of patient history, physical examination, laboratory tests, upper gastrointestinal endoscopy, intravenous cholangiography, ultrasonography, and endoscopic retrograde cholangiopancreatography (ERCP). RESULTS: Measurement of the diameter of the common bile duct was found to be a reliable method as a single noninvasive parameter for diagnosing cholangiolithiasis (sensitivity 100%, specificity 93%), with good predictive power (positive predictive value 0.7, negative predictive value 1.0). The best accuracy achieved noninvasively and without sonography was with a combination of positive patient history and gamma-glutamyl transferase findings (sensitivity 58%, specificity 84%, positive predictive value 0.37, negative predictive value 0.93). ERCP detected additional cholangiolithiasis in 19 of 139 patients (13.7%) and anatomical malformations in three patients. In all 19 patients, the bile ducts were cleared of stones endoscopically within 24 hours, prior to laparoscopic cholecystectomy. Among the 163 patients primarily assigned to laparoscopic cholecystectomy, the protocol diagnostic work-up, including ERCP, allocated three patients (1.8%) to open surgery. Conversion from laparoscopic cholecystectomy to open cholecystectomy occurred in a further two of 158 patients (1.3%). CONCLUSIONS: These results show that routine ultrasonography prior to laparoscopic cholecystectomy can be recommended in order to determine the diameter of the common bile duct. In patients with a ductal diameter of more than 6 mm, ERCP should be performed. Laparoscopic cholecystectomy can be carried out within 24 hours after ERCP and papillotomy.

Adolescent↗
PubMed1997

Specific activation of resting T cells against CA19-9+ tumor cells by an anti-CD3/CA19-9 bispecific antibody in combination with a costimulatory anti-CD28 antibody.

Specific activation of resting lymphocytes for tumor targeting can be achieved by bispecific monoclonal antibodies (bi-mAb) with specificity for tumor antigens and T-cell-activating antigens, respectively, in combination with a costimulatory anti-CD28 antibody. We describe the generation and function of a bi-mAb with specificity for CD3 and for the tumor antigen CA19-9. The bi-mAb OKT3/NSI19-9 was generated by somatic fusion of two hybridoma lines secreting antibodies against CA19-9 and CD3, respectively. A hybrid/hybridoma was established, and its bi-mAb was characterized. In combination with a costimulatory anti-CD28 mAb resting peripheral lymphocytes could be activated specifically with T-cell proliferation and secretion of high amounts of interferon-gamma. On specific T-cell activation, bi-mAb OKT3/NSI19-9 could also redirect the cytotoxic effects of these T cells toward CA19-9+ tumor cells in vitro. Our results indicate that specific activation of resting T cells with bi-mAb OKT3/NSI19-9 in combination with an anti-CD28 mAb can activate resting T cells specifically and leads to antigen-dependent bi-mAb-mediated cytotoxicity against CA19-9+ target cells. This approach may offer new perspectives for the specific immunotherapy of CA19-9+ tumors.

Antibodies, Bispecific↗
PubMed1997

Renal tubular dysfunction in patients with inflammatory bowel disease treated with aminosalicylate.

BACKGROUND: An increasing number of case reports indicate potential nephrotoxicity of 5-aminosalicylic acid (5-ASA), which shares similarities with the chemical structures of both phenacetin and acetylsalicylic acid. AIM: In a point prevalence study the occurrence of sensitive indices indicative of early kidney malfunction was assessed in outpatients with inflammatory bowel disease. METHODS: Routine indices of kidney function (creatinine clearance, urinary protein content, pH, electrolytes, and microscopy) were investigated in 223 patients with inflammatory bowel disease as well as sensitive markers of glomerular or tubular dysfunction (microproteinuria by SDS polyacrylamide gel electrophoresis (SDS-PAGE), urinary concentrations of N-acetyl-beta-D-glucosaminidase, alpha 1-microglobulin, gamma-glutamyltransferase (GGT), alkaline phosphatase (AP), and albumin). Histories of exposure to 5-ASA were assessed by questionnaire. RESULTS: Patients receiving high amounts of 5-ASA, both actual as well as on a lifetime basis, showed an increased prevalence of tubular proteinuria by SDS-PAGE. Raised values for urinary AP and GGT indicate proximal tubular epithelial cells as the source. All other kidney function tests were normal. Analysis of covariates indicated strong associations between disease activity and size of 5-ASA doses as well as alterations in kidney tubular function. CONCLUSION: The possibility exists that high doses of 5-ASA may be associated with proximal tubular proteinuria. This point prevalence study cannot dissect the possible impact of chronic inflammation from high dose 5-ASA treatment and further prospective studies are warranted.

Adult↗
PubMed1996

Ornithine decarboxylase levels in patients with normal colonic mucosa.

We describe a systematic examination of ornithine decarboxylase activity in 120 colonic mucosal samples which were obtained from 20 subjects without colonic disease to establish the normal mean and standard deviation from proximal to distal colon. Ornithine decarboxylase activity was determined by releasing CO2 from DL-[1-14C]ornithine. The mean ornithine decarboxylase levels (CO2 liberated) ranged from 0.26 +/- 0.08 nmol/h.mg protein in the caecum to 0.44 +/- 0.16 nmol/h.mg protein in the rectum. There was no difference between sex and age. Ornithine decarboxylase was not stimulated by guanosine 5'-triphosphate. alpha-Difluoromethylornithine showed an ornithine decarboxylase inhibition of 97.1%. Ornithine decarboxylase activity can be measured with reliable precision and reproducibility. The knowledge of the normal range of ornithine decarboxylase activity in normal human colonic mucosa is necessary for the determination of ornithine decarboxylase activity in pathological findings, especially in malignant transformation.

Adolescent↗
PubMed1996

[Chronic diarrhea--rational diagnosis and therapy].

Chronic diarrhea, defined by frequent bowel movements with decreased stool consistency lasting for longer than 3 weeks represents a major problem in gastroenterology. In addition to the very frequent functional disturbances of irritable bowel syndrome a wide variety of infectious, drug-induced, alimentary, metabolic, hormonal and organic causes requires a thorough evaluation of this symptom. To reach diagnosis an algorithm applying a wide array of diagnostic procedures based on the results of thorough anamnesis, physical examination and stool visit should be followed. In addition to alleviation of symptoms, reconstitution and prevention of nutrional deficits (volume, electrolytes, trace elements, vitamines, calories) therapeutic approaches should eliminate underlying causes whenever possible. Symptomatic relief is provided by substances inhibiting secretion and motility as the opiatagonist Loperamid or anticholinergics. Substitution of vitamins, trace elements, calories, enzymes or bile salts should be adapted to the individual needs. Elimination of a cause of chronic diarrhea is generally provided be anti-infectious therapy, other causes however (e.g. sprue by the elimination of gliadin from diet) may be treated effectively as well.

Chronic Disease↗