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W G Zoller

Publications and source records attributed to W G Zoller.

At least 19 recordsLinked to original sources
PubMed2004

High-dose intravenous vitamin C is not associated with an increase of pro-oxidative biomarkers.

OBJECTIVE: High-dose vitamin C therapy might mediate beneficial clinical effects by counteracting reactive oxygen species. However, concerns are raised whether this approach might provoke diametrical (ie pro-oxidative) effects. The objective was to determine ascorbyl free radical (AFR) concentrations and potential variables of pro-oxidative damage. DESIGN: Crossover study; six healthy males received daily infusions of 750 or 7500 mg vitamin C for six consecutive days. Fasting concentrations of vitamin C and AFR were determined daily. On day 1, concentrations of vitamin C and AFR were measured at 0.25, 0.5, 1, 2, 4 and 8 h post infusion. Plasma concentrations of thiobarbituric acid-reactive substances (TBARS), tocopherol and urine concentrations of 8-oxoguanosine were determined on days 1 and 6. RESULTS: Kinetic studies on day 1 showed that concentrations of vitamin C and AFR displayed parallel dose- and time-dependent kinetics and elimination was highly efficient. Vitamin C and AFR fasting concentrations on days 2-6 were slightly above the baseline, suggesting new, stable steady states. TBARS decreased in both groups, whereas tocopherol and 8-oxoguanosine concentrations remained unchanged. CONCLUSION: Kinetics of AFR largely depend on plasma vitamin C concentrations and AFR is eliminated efficiently. Our data do not support induction of pro-oxidative effects in healthy volunteers given intravenous high-dose vitamin C. SPONSORSHIP: Pascoe Pharmazeutische Präparate GmbH, Giessen, Germany.

Adult↗
PubMed2003

Carotenoids are decreased in biopsies from colorectal adenomas.

UNLABELLED: A lower intake of carotenoids is associated with an increased risk of colorectal cancer. In order to take advantage of the chemopreventive properties of carotenoids, it is necessary to determine carotenoid concentration at the target tissue. As early stages in the adenoma-carcinoma sequence of colorectal cancer might be susceptible to chemoprevention, we sought to determine carotenoid concentrations in biopsies from colorectal adenomas. METHODS: Biopsies from colorectal adenomas and non-involved mucosa were taken from seven patients. For controls, biopsies were obtained from the ascending and descending colon of patients without polyps (n = 5). Concentration of carotenoids (alpha-, beta-carotene, lutein, lycopene, zeaxanthin, beta-cryptoxanthin) were determined by optimizing gradient HPLC-analysis. Results are expressed as pmol/microg DNA. RESULTS: Except for alpha-carotene, all carotenoids could reliably be detected in all specimens. In control patients carotenoid concentrations were highest in the ascending colon, being followed by the descending colon and non-involved mucosa from polyp-carriers. In colorectal adenomas all carotenoids were significantly reduced as compared to-non-involved mucosa (beta-carotene: 0.37 vs 0.19, P<0.03; lycopene: 0.34 vs 0.21, P<0.06, beta-cryptoxanthin: 0.14 vs 0.09, P<0.03, zeaxanthin: 0.18 vs 0.09, P<0.02; lutein: 0.18 vs 0.13,P <0.02). CONCLUSION: All carotenoids investigated are reduced in colorectal adenomas, suggesting that mucosal carotenoids could serve as biomarkers for predisposition to colorectal cancer. Moreover, anti-tumor activity exerted by carotenoids is limited due to mucosal depletion. We speculate that supplementation of a larger array of carotenoids might be beneficial for patients with colorectal adenoma.

Adenoma↗
PubMed2002

[Acquired hemophilia A after an early abortion].

HISTORY: A 30-year-old woman was referred to our clinic because she had developed recurrent spontaneous hematomas of both calves within the last 2 months. 6 months earlier the patient had developed an ovarian hyperstimulation syndrome after ovarian stimulation treatment and intrauterine insemination. Shortly afterwards a missed abortion (8 (th) week) had been diagnosed. A curettage was carried out. INVESTIGATIONS: Routine coagulation tests confirmed a prolongation of aPTT to 90 s and a lupus anticoagulant. A high-titre factor VIII inhibitor (56 Bethesda units) was identified. TREATMENT AND COURSE: Given these facts an acquired post-partum hemophilia was diagnosed. The patient was treated with prednisolone and immunoglobulins. The aPTT shortened to normal values. The factor VIII inhibitor and lupus anticoagulant disappeared. There were no further hematomas. CONCLUSIONS: The simultaneous occurrence of antibodies in an altered immune state such as pregnancy is well known. In our case, acquired factor VIII inhibitor was found after an early abortion. Treatment with steroids and immunoglobulines led to the disappearance of factor VIII inhibitor and lupus anticoagulant.

Abortion, Missed↗
PubMed2001

Meta-analysis: efficacy of therapeutic regimens in ongoing variceal bleeding.

BACKGROUND AND STUDY AIMS: Variceal bleeding is a major cause of mortality in liver cirrhosis. Therapeutic options include medical (vasoconstrictive/vasoactive drugs) and endoscopic (sclerotherapy/ligation) treatments. Most studies evaluating acute esophageal bleeding have included patients with both ongoing and recent bleeding. Therefore therapeutic efficacy in ongoing bleeding may not have been adequately determined in these studies. A meta-analysis was performed for two reasons: first to compare directly the various treatments in the case of ongoing bleeding, as this would not be accomplished by a single trial, and secondly, to determine the success rates of each treatment option based on a larger number of patients. METHODS: An extensive Medline search identified 13 randomized controlled trials with precise statements of the number of patients with ongoing bleeding and their clinical outcomes. All studies followed a similar design and a Q test excluded heterogeneity of the studies. Data were pooled and cumulative success rates were calculated. RESULTS: Ligation appeared to be the most effective treatment (91.0 %, 95 % CI 82.4-96.3 %); it was significantly more successful than vasoconstrictive treatment (vasopressin/terlipressin 68.7 %, 61.7-75.2 %; P < 0.002, chi-squared-test) or vasoactive treatment (somatostatin/octreotide, 75.9 %, 68.1-82.6 %; P < 0.02) treatment, but was not statistically better than sclerotherapy (81.1 %, 71.7-88.4 %). The latter therapy was not statistically superior to medical treatment options. Calculations of estimated true effects, which take into account the weight of each study, rendered similar results. CONCLUSION: Ligation is the most effective treatment option. No significant difference was found between the efficacy of sclerotherapy and treatment with somatostatin or octreotide.

Adult↗
PubMed1999

Colorectal cancer: A rational follow-up program adapted to patient's individual risk of recurrence and review of the literature.

Follow-up programs in patients with colorectal cancer have been criticized concerning their efficacy. Uniform programs for all patients as practised during the last decade did neither influence survival nor did they improve the number of secondary tumor resection for cure. Therefore we developed a follow-up program that stratifies according to patient s healthiness, residual tumor and the expected risk of tumor recurrence. Patients were divided into three categories: patients with low or high risk of tumor recurrence and patients treated for palliation. By such an approach the number of apparative examinations and the cost of a follow-up program could be theoretically reduced by more than 50%.

Colorectal Neoplasms↗
PubMed1999

[3-dimensional sonography for volume determination of liver tumors--report of initial experiences].

In a clinical trial the accuracy of volumetry by use of three-dimensional ultrasound (3-D-US) in comparison to three-dimensional computer tomography (3-D-CT) was evaluated. Overall, 42 patients with focal hepatic lesions were investigated with 2-D- and 3-D ultrasound. In 11 patients additional computerized tomographic arterial portography using spiral technique was performed. The volumes of the lesions were calculated using the ellipsoid formula (for 2-D- and 3-D-US) as well as with a planimetric reconstruction for 3-D-US and 3-D-CT. In addition the intra- and inter-investigator variability of 3-D ultrasound was determined. The volume of the investigated liver lesions (planimetric reconstruction with 3-D ultrasound) ranged between 1.5 cm3 and 1231 cm3 with a mean volume of 155 cm3 and a median volume of 68 cm3. The deviation of 2-D-US vs 3-D-CT was -62% to +68%, in the case of 3-D-US (ellipsoid) vs 3-D-CT it was -28% to +9%, and for 3-D-US (planimetry) vs 3-D-CT it was -21% to +9%. The concordance index kappa was 0.886, showing very good agreement between the two investigators. The intra-investigator variability was 5%. Our data show that volume measurement by use of 3-D-US in independent of the investigator. With regard to accuracy of volume measurements 3-D-US is comparable to 3-D-CT but more precise than 2-D-US. These results indicate that 3-D-US may be applied in the follow-up of tumor patients as an alternative diagnostic procedure to computer tomography. In addition 3-D-US might be useful in planning liver resections by virtue of better evaluation of the volume of the liver tissue remaining after resection and better visualization of the topography of liver tumors and major hepatic vessels.

Artificial Intelligence↗