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Biomedical subjects

W Wiesner

Publications and source records attributed to W Wiesner.

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

FDG PET-negative liver metastases of a malignant melanoma and FDG PET-positive hurthle cell tumor of the thyroid.

A Hurthle cell tumor (oncocytoma) of the thyroid presented as a hypermetabolic focus in a fluorodeoxyglucose positron emission tomography (FDG PET) study which was performed as staging procedure in a patient with malignant melanoma. This finding led to the initial diagnosis of a metastasis. In contrast, multiple liver metastases, seen on MRI and sonography, did not show any increased FDG uptake. Cytology results of one liver mass confirmed a melanoma metastasis, and of the neck mass, a Hurthle cell tumor. The Hurthle cell tumor was, based on clinical evidence, thought to be benign. This is the first description of a FDG PET-positive benign Hurthle cell tumor, with FDG PET-negative liver metastases of a malignant melanoma, in the same patient.

Adenoma, Oxyphilic↗
PubMed1998

MR imaging of the augmented breast.

Mammographic evaluation of the augmented breast is challenging, since breast implants obscure significant amount of breast tissue while diminishing the effect of compression. Posttherapeutic scarring can make mammographic interpretation even more difficult. MRI has thus evolved into the modality of choice for diagnosing implant complications as well as detection of primary or recurrent breast cancer in these patient population. The present article attempts to give an overview of the MR findings of different breast augmentation and reconstruction techniques, i. e. prosthetic breast implants, breast reconstruction with autogenous tissue, free silicone injections and fat grafts, and their complications.

Adipose Tissue↗
PubMed1998

[The MRT and MRA of kidney transplants--vascular and perfusion assessment].

PURPOSE: To document the value of fast contrast enhanced-sequences in the assessment of the vascular supply and parenchymal perfusion in renal transplants. PATIENTS: 18 recipients of a renal transplant were examined with a 1.5-tesla-MR-system. The protocol included fast contrast enhanced 3D MR angiography and coronal 2D GRE sequences. The transplant artery and vein were assessed as well as regional parenchymal perfusion. RESULTS: 3D MRA detected three transplant artery stenoses and one occlusion. In addition, two renal vein thromboses and one compression were identified. Perfusion deficits were documented in 8 renal transplants: renal infarction (n = 4), cortical necrosis (n = 2), acute tubular necrosis (n = 1) and venous ischemia (n = 1). Fluid collections were documented as well as dilation of the collecting system and abnormalities of the surrounding tissues. CONCLUSION: Contrast enhanced MRI and MRA permit a comprehensive assessment of renal transplants without inducing nephrotoxicity.

Adult↗
PubMed1998

[Gastric pouch dilatation: complications after laparoscopic implantation of a silicone gastric band in pathologic obesity].

In 20 patients with morbid obesity a laparoscopic silicon gastric banding was installed using a LAP-BAND. All patients were examined postoperatively with water-soluble oral contrast material according to the usual protocol. 8 weeks after the operation a second control with thickened barium sulfate was added to measure and adjust the width of the silicon band. There were no early postoperative complications. But in the follow-up three patients presented with a pathologic gastric pouch-dilatation. This severe complication, which can have different etiologies, requires early detection and specific therapy.

Administration, Oral↗
PubMed1988

Purification and characterization of a novel bacterial non-heme chloroperoxidase from Pseudomonas pyrrocinia.

The first bacterial chloroperoxidase that is capable of catalyzing the chlorination of indole to 7-chloroindole was detected in Pseudomonas pyrrocinia ATCC 15958, a bacterium that produces the antifungal antibiotic pyrrolnitrin (Wiesner, W., van Pée, K.H., and Lingens, F. (1986) FEBS Lett. 209, 321-324). Here we describe the purification and characterization of this bacterial non-heme chloroperoxidase. The enzyme was purified by DEAE-cellulose chromatography at different pH values, molecular sieve chromatography, and Bio-Gel HTP hydroxylapatite. After the last purification step, chloroperoxidase was homogeneous by polyacrylamide gel electrophoresis and ultracentrifugation. Based on gel filtration and ultracentrifugation results, the molecular weight of the enzyme was 64,000 +/- 3,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a single band with the mobility of a 32,000 molecular weight species. Therefore, in solution at neutral pH, this chloroperoxidase is a dimer. The enzyme did not exhibit any absorbance in the visible region of the spectrum. The isoelectric point was 4.1. Chloroperoxidase was specific for I-, Br-, and Cl- and was not inhibited by azide, but was inhibited by cyanide and F-. This procaryotic chloroperoxidase catalyzed the bromination of monochlorodimedone but not its chlorination and has no peroxidase or catalase activity. The pH optimum of the enzyme was between 4.0 and 4.5, and the enzyme was stable between pH 3.5 and 8.5 and showed no loss of activity when incubated at 60 degrees C for 2 h. Chloroperoxidase also chlorinated 4-(2-amino-3-chlorophenyl) pyrrole to yield aminopyrrolnitrin, the immediate precursor of pyrrolnitrin. This suggests very strongly that chloroperoxidase is involved in the biosynthesis of the antibiotic pyrrolnitrin.

Amino Acid Sequence↗
PubMed1986

Detection of a new chloroperoxidase in Pseudomonas pyrrocinia.

A new chloroperoxidase could be detected in Pseudomonas pyrrocinia ATCC 15,958, a bacterium that produces the antifungal antibiotic pyrrolnitrin. This enzyme was separated from a ferriprotoporphyrin IX containing bromoperoxidase which was also produced by this bacterium. The enzyme is capable of catalyzing the chorination of indole to 7-chloroindole. This procaryotic chloroperoxidase requires the presence of H2O2 and can also brominate monochlorodimedone, but cannot catalyze its chlorination. This enzyme is the first chloroperoxidase described from procaryotic sources.

Chloride Peroxidase↗
PubMed1985

Purification and properties of bromoperoxidase from Pseudomonas pyrrocinia.

A bromoperoxidase was purified and partially characterized from Pseudomonas pyrrocinia ATCC 15958, a bacterium that produces the antifungal antibiotic pyrrolnitrin. The purified enzyme preparation was homogeneous as determined by polyacrylamide gel electrophoresis and ultracentrifugation. The molecular mass of the enzyme was estimated to be 154 kDa +/- 3 kDa as determined by gel filtration and ultracentrifugation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed a single band with the mobility of a 76-kDa species. Therefore, in solution at neutral pH, bromoperoxidase exists as a dimeric species. The isoelectric point was 5.0. The prosthetic group of this procaryotic bromoperoxidase was ferriprotoporphyrin IX. The spectral properties of the native and reduced enzyme are reported. The purified enzyme showed brominating as well as peroxidase and catalase activity.

Electrophoresis, Polyacrylamide Gel↗
PubMed1984

Zinc, copper, manganese and gold content of the hair of infants.

In the hair of 41 normal newborn children the amounts of the trace elements zinc, copper, manganese and gold were followed up longitudinally by neutron activation analysis, the samples being taken on the 1st day of life, between the 63th and 109th days, the 200th and 240 th as well as between the 368th and 478th days of life. In the newborn children no correlations among their hair trace elements themselves and with the duration of normal pregnancy, birth weight, weight percentiles according to Lubchenko et al. [21] and birth length were found. The zinc content of 212 +/- 63 ppm, the copper content of 8.1 +/- 2.3 ppm and the manganese content of 0.211 +/- 0.366 ppm agreed well with values in the literature from different parts of the world. The hair gold content was found to be 0.086 +/- 0.006 ppm. In early childhood the trace element contents do not exhibit any dependence on sex. The investigation of trace elements in the hair of babies resulted in the remarkable observation that in the first three months of life zinc, copper and gold contents shows a considerable increase to multiple levels of the birth values, followed by a decrease. This is important for the interpretation of hair trace element analyses in infants. There are significant positive correlations among zinc, copper and gold contents in hair. It must be emphasized that gold, although classified as a non-essential element, behaves in the hair of infants just like the physiologically important essential trace elements zinc and copper.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗