Biomedical subjects

J Franke

Publications and source records attributed to J Franke.

At least 19 recordsLinked to original sources

PubMed2000

[Osteoporosis in the male].

BACKGROUND: Osteoporotic fractures occur frequently also in men. Epidemiologic data from Germany indicate that more than 900,000 men are affected by osteoporotic fractures. Diagnosis and therapy of male osteoporosis are hampered by a lack of clinical studies. DIAGNOSIS: Risk factor analysis, conventional spine X-rays, bone densitometry and a limited number of serum and urine analyses contribute to the diagnosis of osteoporosis and the assessment of future fracture risk. Bone densitometry at the femoral neck is superior to measurements at the lumbar spine because of the high prevalence of degenerative changes at the lumbar spine in elderly men. Major risk factors for osteoporosis are hypogonadism, glucocorticoid therapy, hypercalciuria, gastrointestinal disease, and high alcohol consumption. In individual cases, bone histology or additional biochemical studies are needed to establish the cause of osteoporosis. THERAPY: Calcium and vitamin D deficits should be substituted both in prevention and treatment of male osteoporosis. Testosterone replacement therapy is effective in hypogonadism. In primary osteoporosis and in corticosteroid-induced osteoporosis, bisphosphonates (cyclical etidronate, alendronate) and fluorides are therapeutic options. CONCLUSION: Important principles in the care of men with osteoporosis are the transfer of knowledge established for postmenopausal osteoporosis and the rigorous search for secondary osteoporosis aiming at treatment of the underlying cause. Large prospective randomized trials aiming at the reduction of fracture rate in male osteoporosis are missing. They are urgently needed.

Aged↗

PubMed2000

[Value of positron emission tomography (18F-FDG-PET) in the diagnosis of recurrent rectal cancer].

INTRODUCTION: Diagnosis of extraluminal recurrent rectal cancer may be difficult. Currently the diagnosis is based on routine imaging procedures. Diagnosis often remains unverified until histological proof can be acquired by transcutaneous biopsy or operative exploration. The diagnostic value of positron emission tomography (PET) in recurrent rectal cancer was evaluated in a prospective study at the Department of Surgery of the RWTH Aachen University Hospital. The aim of the study was to assess the sensitivity of PET in the detection of recurrent rectal cancer in comparison with conventional procedures. Furthermore, the valency of PET in the diagnosis of the local expansion and metastasis was evaluated. METHODS: Since June 1997, PET has been performed in all patients with suspected recurrent rectal cancer. The examined area reaches from the neck to the symphysis. Visual assessment follows transversal, frontal and sagittal sector scans. Enhanced focal FDG uptake over the physiological enrichment of the environment (e.g., urinary tract) was defined as a criterion of malignancy. The findings were compared with the results of routine diagnosis and histological examinations. RESULTS: Up to now, 23 patients have been subjected to a PET examination. In 17 cases, a local recurrence could be proved. An intrahepatic metastasis was found in 11 patients, pulmonary metastasis in 3 patients, lymph-node metastasis in 5 patients, and a peritoneal carcinomatosis was found in 4 patients. All these findings were confirmed by histological examinations after biopsy and operation or by other imaging procedures and the clinical follow-up. CONCLUSIONS: The controlled results show that PET can detect recurrent rectal cancer and its metastasis with great precision. PET seems to be a useful additional examination in the diagnosis of extraluminal recurrent rectal cancer.

Biopsy↗

PubMed2000

Adaptation of reptilian paramyxovirus to mammalian cells (Vero cells).

The reptilian paramyxovirus GOV was successfully adapted to Vero cells in 80 passages at 30 degrees C. The virus replicated with HA titres of 1:64 and 10(7.5) TCID50/ml in the heterologous host cells forming syncytia, giant cells and cytoplasmic inclusion bodies. After 80 passages GOV was identified by immunofluorescence, by immune electron microscopy and by PCR. Sequencing of RT-PCR products of GOV after 80 passages did not reveal changes in the nucleotide sequence of the partial L-gene of GOV.

Animals↗

PubMed2000

Bootstrapping neural networks.

Knowledge about the distribution of a statistical estimator is important for various purposes, such as the construction of confidence intervals for model parameters or the determination of critical values of tests. A widely used method to estimate this distribution is the so-called boot-strap, which is based on an imitation of the probabilistic structure of the data-generating process on the basis of the information provided by a given set of random observations. In this article we investigate this classical method in the context of artificial neural networks used for estimating a mapping from input to output space. We establish consistency results for bootstrap estimates of the distribution of parameter estimates.

Artifacts↗

PubMed2000