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W Beyer

Publications and source records attributed to W Beyer.

At least 37 records · Page 2Linked to original sources
PubMed1998

Histological verification of positive fluorine-18 fluorodeoxyglucose findings in patients with differentiated thyroid cancer.

Fluorine-18 fluorodeoxyglucose and positron emission tomography (FDG-PET) is a new imaging modality used in the follow-up of patients with differentiated thyroid cancer if the results of (131)I scintigraphy are negative in spite of an elevated thyroglobulin level. The aim of this retrospective analysis was to estimate the value of FDG-PET regarding the operability of patients with positive findings. From January 1994 to October 1997, we investigated 60 patients with differentiated thyroid carcinoma by FDG-PET. Thirteen patients were operated on after positive findings. Most of these lesions were suspected of having lymph-node involvement or local recurrences in the thyroid bed. One patient showed a solitary distant metastasis in the scapula. Thirteen of 16 operations in these 13 patients confirmed the suspected involvement of thyroid cancer. The false-positive findings were caused by inflamed lymph nodes in two cases and benign thymus tissue in one case. We conclude that PET is a useful diagnostic tool to guide early surgical therapy in patients with (131)I negative differentiated thyroid carcinoma.

Adenocarcinoma, Follicular↗
PubMed1998

[Computerized tomography and F-18-FDG positron emission tomography in staging of malignant lymphomas: a comparison].

PURPOSE: To determine the value of F-18-FDG-positron emission tomography (FDG-PET) compared with computed tomography (CT) in the staging of malignant lymphomas. MATERIAL AND METHOD: 50 patients with biopsy-proven lymphoma were studied with FDG-PET and CT. The results in initial, posttherapeutic and staging of recurrence were compared. RESULTS: 37 of 65 FDG-PET were identical with CT. 28 studies showed differences. 14 post-therapeutically and one of the initial studies led to downstaging by FDG-PET were as upstaging resulted in one case of initial staging. In two cases false positive pulmonary FDG accumulations caused an upstaging. CONCLUSION: FDG-PET was at least comparable to CT in recording the extension of a newly diagnosed lymphoma, or its recurrence. Upstaging according to FDG-PET occurred only once in initial staging. FDG-PET plays its most important role in the evaluation of residual mass in CT after therapy by accumulating FDG in viable tumour rather than in fibrotic tissue. 14 cases of downstaging according to FDG-PET resulted.

Adolescent↗
PubMed1998

Suitability of repetitive-DNA-sequence-based PCR fingerprinting for characterizing epidemic isolates of Salmonella enterica serovar Saintpaul.

Three molecular typing methods, repetitive-sequence-based PCR (rep-PCR) fingerprinting, plasmid profiling, and arbitrarily primed PCR fingerprinting, were used to characterize isolates of Salmonella enterica serovar Saintpaul. Most of the isolates were obtained from epidemic human cases of food-borne salmonellosis, together with some from the food material suspected to be the source of infection, and a few were obtained from other cases apparently not related to the epidemic. All three methods adequately discriminated the epidemic strain from other strains of the serovar. In addition several isolates from human cases which are not identical to the epidemic strain were found. These isolates therefore must have been responsible for some sporadic infections, which were only temporally related to the epidemic. These strains showed a high degree of similarity to a strain isolated from a turkey. rep-PCR fingerprinting with REP-Dt primers and primer ERIC1R, applicable even to crude cell lysates, offers an attractive choice as a primary method for the discrimination of various Salmonella serotypes as well as isolates within serotype Saintpaul.

Bacterial Typing Techniques↗
PubMed1998

[Chest X ray: routine indication in the follow-up of differentiated thyroid cancer?].

AIM: This retrospective study sought to elucidate whether routine chest x-ray is still useful for detection of pulmonary metastases in low risk patients despite the high sensitivity of the tumor marker thyroglobulin. METHOD: The hospital files of 609 patients with well-differentiated thyroid cancer were analysed. Pulmonary formation of metastases was diagnosed in 50 patients. The thyroglobulin value at the time of diagnosis was compared with the chest x-ray findings and, if present, additional diagnostic information such as Iodine-131 whole body scintigraphy (WBS) and thorax CT. RESULTS: The sensitivity of the chest x-ray to detect pulmonary metastases was at 52% lower than that of WBS (64%), thorax CT (82%) and thyroglobulin during suppression therapy (86%). Among the patients with papillary carcinoma stage I and II (UICC 1987), only 1 patient developed pulmonary metastases during follow up. In this low risk group of patients, detection of lung metastases exclusively by chest x-ray, without elevation of thyroglobulin level is extremely rare (calculated probability 1/4000) and associated with considerable costs. CONCLUSION: Routine, life long chest x-ray in low risk patients without a suspected recurrence (e.g. positive thyroglobulin) needs to be reconsidered.

Carcinoma, Papillary↗
PubMed1997

Whole-body positron emission tomography (PET) for diagnosis of residual mass in patients with lymphoma.

BACKGROUND: PET using 18fluorodesoxyglucose (FDG) may offer the possibility of differentiating vital from necrotic residual masses. PATIENTS AND METHODS: Seventeen patients with HD and 17 patients with NHL underwent FDG-PET following therapy. According to staging by routine methods at diagnosis, 7 patients presented stage I, 13 stage II, 5 stage III, and 9 stage IV. A dose of 250-400 MBq FDG was injected and whole-body PET was performed 30-60 minutes later. RESULTS: Residual mass was found in 32 patients with routine methods. FDG-PET was negative in 17 patients, who were considered to be in CR. None of them relapsed (median follow-up 63 weeks ). FDG-PET was positive in 17 patients. Sixteen patients had residual mass with routine methods. Four patients received radiation after PET. Their median follow-up is 58 weeks without relapse. Two other patients with lasting CR had FDG uptake outside the residual mass--one with confirmed pneumonia. Five patients had histologically confirmed lymphoma, 2 patients relapsed according to routine methods. One patient is likely to be false positive because of fracture at lymphoma site. Seven of 10 patients with FDG uptake in the residual mass after completed therapy relapsed. According to routine restaging, 2 patients achieved CR. In 1 patient an additional focus was found in the humerus in spite of normal scintigraphy with histologically confirmed lymphoma. There were no false-negative results, but 3 false-positive results inside and 2 false-positive results outside the residual mass after completed therapy. CONCLUSIONS: PET performed for evaluation of residual mass after treatment of lymphoma has a high predictive value.

Adult↗
PubMed1996

Pharmacokinetics of 5-aminolevulinic-acid-induced porphyrins in tumour-bearing mice.

Photodynamic therapy and photodynamic diagnosis help to support efficient treatment of superficial and early-stage cancer. During the last few years, 5-aminolevulinic acid (5-ALA), a precursor of haemoglobin in the haem biosynthetic pathway, was used to stimulate endogenous porphyrin production. In the following the time dependence of 5-ALA-induced porphyrin concentration will be investigated on several tissues in an in-vivo tumour model. 5-ALA was administered intravenously at a concentration of 50 mg-1 body weight. According to a certain time schedule the animals were sacrificed and 12 different organs as well as the tumour were removed. During excitation with the violet light of a Kr+ laser, porphyrin fluorescence spectra in the range 550-750 nm could be detected on the tissue samples. The intensity of the emission spectra at lambda = 635 +/- 2 nm was taken as a measure of the porphyrin concentration. All tissues showed porphyrin fluorescence. Brightest fluorescence was found on the tumour. A maximum contrast of the fluorescence intensity between the tumour and the non-malignant organs of up to 30 was observed at 4-6 h post-injection. The kinetics of the porphyrin concentration depend on the organ. Simple mathematical models will be derived and discussed.

Aminolevulinic Acid↗
PubMed1996

Labeling Salmonella live vaccine strains with the lux operon from Vibrio fischeri improves their detection and discrimination from wild type.

Genetic labeling of Salmonella live vaccine strains, ZoosaloralR H and TAD Salmonella vacR T, with part of or the entire lux operon of the marine bacterium Vibrio fischeri allows for detection and discrimination of these vaccine strains in the course of routine bacteriological culture procedures, without disturbance of such procedures and without the requirement for extra materials and working steps. The label is either plasmid coded or chromosomally integrated by a Tn5 transposon vector. One of the plasmid constructs contains a truncated lux operon raising the requirement for the exogenous addition of the aldehyde substrat of the luciferase to induce light production. All strains constructed produced light sufficiently bright to detect their colonies on the surface of a routinely used plate in the dark with the naked eye.

Animals↗
PubMed1996

Systems for light application and dosimetry in photodynamic therapy.

Successful photodynamic therapy requires homogeneous irradiation and light detection for dosimetry. Light delivery devices and detectors for treatment of spherical and cylindrical hollow organs have been developed. For photodynamic therapy of multifocal superficial bladder tumours a catheter with an isotropic emitter is centred by a balloon. Light which is backscattered from the tissue surface is used for on-line dosimetry. The irradiation and dosimetry concept has been proven by computer simulations for a non-spherical bladder shape. Larynx, bronchi, oesophagus and cervix have been irradiated by devices adapted to the shape of the organ. The light distribution is homogenized by multiple backscattering from a nearly white layer in contact with tissue, a promising method also for hollow organs with irregular geometry. The homogeneity of the light distribution as well as the dosimetry have been improved by the devices to be presented.

Humans↗
PubMed1995

Comparison of low-field (0.2 Tesla) and high-field (1.5 Tesla) magnetic resonance imaging of the knee joint.

In order to evaluate the reliability of low-field magnetic resonance imaging (MRI), we examined 22 patients using a 0.2-Tesla magnet unit in comparison with a 1.5-Tesla system. The MRI findings were compared with the intraoperative findings. Concerning the diagnosis of meniscal tears, the gradings of both systems differed only in three cases. The specificity was 97% (both systems), the sensitivity 83% (1.5 T) versus 75% (0.2 T). The sensitivity and specificity for detection of tears of the anterior cruciate ligament were 100% and 75%, respectively, for both systems. The gradings differed only in two cases. In our series we found 6 full-thickness cartilage defects that were all detected with the high-field imaging system. They were missed by the low-field imaging system in 5 cases. The results suggest that both systems are reliable in diagnosing meniscal tears and ruptures of the anterior cruciate ligament.

Adolescent↗
PubMed1995

[Functional limitation of the forearm after shaft fracture in childhood. Possible role of the antebrachial interosseous membrane: MRI and ultrasound studies].

Based on follow-up examinations of 16 patients aged 5 to 15 years, the integrity of the interosseous membrane following forearm shaft fracture was evaluated. The examinations which included magnetic resonance imaging (MRI) and ultrasound scanning of both the fractured and the nonfractured forearms were conducted 4 to 81 months after fracture. Using a 1.5 T MR tomograph, we obtained 20 cross-sectional images arranged over the entire length of the forearm which was in neutral position, while sonographicly at 7.5 MHz we obtained cross-sectional views of the proximal, middle and distal forearm thirds with the forearm in pronation, neutral position and supination at a time. The MR image of the interosseous membrane is a thin hypointense line, occasionally showing low contrast irregularities on the fractured side such as thickenings, tears or curvature inconstancies which would suggest membrane alterations. However, these alterations appear to be less than expected. They are not clearly seen in the ultrasound views, where the interosseous membrane is found as an echorich line. According to our preliminary results, there seems to be a correlation between MR-detected interosseous membrane alterations and initial fracture dislocation as well as functional fracture outcome, particularly forearm rotation.

Adolescent↗
PubMed1995

A nested PCR method for the detection of Bacillus anthracis in environmental samples collected from former tannery sites.

A nested PCR has been developed to detect Bacillus anthracis spores in natural soil and waste samples which may be heavily contaminated by organic and inorganic compounds as is the case at former tannery sites. Outer and inner pairs of primers were designed from the protective antigen gene of the plasmid pX01 as well as from the genes B and C of the capsule region of the plasmid pX02. The DNA was prepared from an enrichment broth after killing the vegetative cells by H2O2 treatment. The method allows the detection of less than 10 spores per 100 g of the original soil sample. This is between 10(4)-fold and 10(7)-fold more sensitive than the conventional culture diagnosis.

Bacillus anthracis↗
PubMed1995

[Use of photodynamic laser therapy in gynecology].

OBJECTIVE: Dysplasia of the vulva and uterine cervix are often multicentric, tend to recur and have mostly to be treated by surgical procedures. The photodynamic laser therapy (PDT) may be an alternative, which selectively destroys neoplastic tissue after topical delta-aminolevulinic acid (ALA) used as a photosensitizer. METHODS: We measured the distribution of fluorescence in dysplastic and nondysplastic tissue after topical application of ALA in 27 patients with dysplasia. In 3 vulvar and 2 cervical dysplasias, PDT was performed. RESULTS: We could show a selective enrichment of endogenous porphyrins in dysplastic tissues, whereas benign tissue showed no fluorescence. The fluorescence was limited to the mucosa. The heterogeneous fluorescence pattern was influenced by the duration of ALA application. In the treated patients, cytological and clinical parameters showed improvement after use of PDT. The longest recurrence-free interval from treatment up to date is 15 months (range 3-15 months). CONCLUSIONS: After first results of penetration studies and clinical follow-up, PDT after topical ALA application seems to be a good alternative to surgical procedures in dysplastic changes of the genital tract.

Adult↗
PubMed1995

[Computer-controlled laser irradiation unit for studies of light-induced processes in cell cultures].

For the photodynamic treatment of tumours, synergistic effects of photosensitizing substances and light (today usually laser light) are used. With the aim of optimizing photosensitizing drugs and therapy, the effects of light and drug dose were studied in cell experiments. To automate and standardize such in vitro experiments, a laser irradiation chamber was developed. Cells cultured from tumour cell lines are placed on micro-titre plates or in petri dishes, together with the photosensitizer, and subsequently irradiated in the irradiation chamber with a well-defined dose of laser light of a wavelength corresponding to the absorbance of the photosensitizing agent. The plates or dishes are irradiated from below. In this way, light dose errors due to refraction from the meniscus of the cell suspension as occurs with irradiation from above, are avoided. During irradiation, speckle effects on the underside of the plates or petri dishes lead to variation in irradiation. A vibrator keeps the light transmission fibre and thus speckle pattern in motion, guaranteeing a homogeneous irradiation of the cells.

Computer Graphics↗
PubMed1993

Essential trace elements in humans. Serum arsenic concentrations in hemodialysis patients in comparison to healthy controls.

Serum arsenic concentrations of persons suffering from renal failure and undergoing hemodialysis treatment (n = 85) and of healthy controls (n = 25) were determined by hydride-generation AAS technique after microwave digestion. The results were evaluated by comparing the values of both groups, considering physiological factors and individual data, as well as comorbid conditions of the hemodialysis (HD) patients. Serum arsenic levels were diminished in the patient group compared with controls (mean values 8.5 +/- 1.8 ng/mL vs 10.6 +/- 1.3 ng/mL). Furthermore, additional diseases within the hemodialysis group, particularly injuries of the central nervous system (CNS), vascular diseases, and cancer, were correlated to occasionally markedly decreased serum arsenic concentrations. It was concluded that arsenic homeostasis is disturbed by HD treatment and certain additional diseases. Desirable arsenic concentrations in the body seem to be reasonable. This consideration results in the conclusion that arsenic could play an essential role in human health. Thus, reference arsenic concentrations in different human tissues and body fluids should be established in order to recognize not only arsenic intoxication, but also arsenic deficiency. Perhaps arsenic deficiency contributes to the increased death risk of HD patients, and therefore, arsenic supplementations for patients with extremely low serum arsenic concentrations should be taken into account.

Arsenic↗
PubMed1992

Characterization of the virulence regions in the plasmids of three live Salmonella vaccines.

Three live Salmonella vaccines, Zoosaloral "Dessau", Bovisaloral "Dessau", and Suisaloral "Dessau" successfully used in veterinary medicine in eastern Germany were analysed for their plasmid DNA content. Plasmids of 60 MDa (S. typhimurium), 55 MDa and 26 MDa (S. dublin) and 34 MDa (S. choleraesuis) were found. The three large plasmids contained a virulence region as shown by restriction enzyme analysis and hybridization studies with virulence-region-specific DNA probes. Restriction enzyme pattern analysis of the whole plasmids revealed differences between vaccine strains and parental strains. We wanted to know if there were alterations within the virulence region of the vaccine strain plasmids compared with parental strains caused by the attenuation procedure. Therefore, the 6 kb-Cla I fragments of several plasmids were cloned and characterized by restriction enzyme fingerprinting. The expression of the Cla I fragment-encoded proteins was analysed in the minicell-producing strain DS 410. The experiments revealed that the restriction pattern of the 6 kb-Cla I fragments of Zoosaloral and Bovisaloral as well as the PAGE pattern of virulence-region-encoded proteins were in complete accordance with one another, between vaccine strains and the parental strain of Zoosaloral, and with a wild-type strain of S. typhimurium.

Nucleic Acid Hybridization↗
PubMed1992

The sensitizing capacity of the antioxidants propyl, octyl, and dodecyl gallate and some related gallic acid esters.

8 alkyl gallates, including the widely used antioxidants propyl, octyl, and dodecyl (= lauryl) gallate, have been subjected to experimental sensitization in guinea pigs. Using a modern sensitization procedure, the results showed that all gallates are moderate to strong contact sensitizers: dodecyl (= lauryl) gallate was found to be the strongest. A characteristic correlation between side chain length and mean response was observed, giving a maximum of sensitization at a length of 12 carbon atoms (dodecyl gallate). A literature review revealed that the frequency of reports of allergic contact dermatitis from antioxidants of the gallate type has increased in the last 4 years. In most cases, the moderate sensitizer propyl gallate was the source of sensitization.

Animals↗