Biomedical subjects

J Leissner

Publications and source records attributed to J Leissner.

22 records · Page 2Linked to original sources

PubMed1995

Three-dimensional reconstruction of anatomic structures using serial sectional images.

Precise three-dimensional modeling and visualization of human anatomy and pathology are important in medicine. Three-dimensional models have applications in the training of medical students and residents and aid physicians evaluate and determine appropriate clinical management of patients. Three-dimensional reconstructions of radiographic images have been available for some time now. However, electronic reconstruction of these images often requires the utilization of large computer systems or workstations and also requires highly trained and specialized technicians to perform the task. This paper presents a technique for precise three-dimensional reconstruction of the human anatomy and pathology using an 80486 IBM compatible personal computer and commercially available software. We reconstructed the images from computed tomography scans. Implementation of this technique does not require extensive training and shows good results after a short learning curve.

Computer-Assisted Instruction↗

PubMed1995

[3-dimensional reconstruction for planning surgical reconstruction of tumors in the single kidney].

Organ-sparing renal surgery for renal cell carcinoma has greatly increased in importance over the last few years owing to the widespread application of ultrasound examination. When a normal contralateral kidney is present the indications for organ-sparing surgery are very strict. Our patient presented with a large tumour in a single kidney and, though fully informed about all the risks involved, insisted upon an organ-sparing operation. In planning and execution of the operation we were much assisted by the use of a three-dimensional reconstruction made from the CT scan carried out preoperatively, because this showed the exact position and size of the tumour. We report on the course of the patient's illness and present a simple three-dimensional reconstruction technique.

Carcinoma, Renal Cell↗

PubMed1990

The effects of phorbol esters on choline phospholipid hydrolysis in heart and brain.

The efflux of choline was determined in rat striatal slices, incubated chicken atria and perfused chicken hearts. 4 beta-Phorbol-12 beta,13 alpha-dibutyrate (PDB) and 4 beta-phorbol-12 beta-myristate, 13 alpha-acetate (PMA) were used to stimulate protein kinase C. The other phorbol esters, 4 beta-phorbol-13 alpha-acetate (PAc) and 4 alpha-phorbol-12 beta,13 alpha-didecanoate (4 alpha PDD), known to be inactive, were tested to evaluate the specificity of the responses. PDB markedly enhanced the efflux of choline in all of the three preparations. The PDB-evoked efflux of choline in incubated chicken atria was equal to the net production of choline and, therefore, was not caused by translocation of intracellular free choline. After inhibition of the cholinesterase activity, PDB linearly increased the efflux of choline in rat striatal slices, but failed to alter the spontaneous efflux of acetylcholine. Thus acetylcholine did not serve as the source of the PDB-evoked efflux of choline. PMA was as effective as PDB, whereas PAc and 4 alpha PDD failed to alter the choline efflux in the perfused heart. Both infusion of a Ca2(+)-free EGTA-containing Tyrode solution and mepacrine reduced the spontaneous efflux of choline by about 40% and blocked the PDB-evoked efflux of choline. In contrast, a Ca2(+)-free solution without EGTA failed to alter the spontaneous and the PDB-evoked choline efflux. It is concluded that phorbol esters stimulate the hydrolysis of choline-containing phospholipids in heart and brain via activation of protein kinase C.

Animals↗

PubMedDate not supplied

Prognostic value of p53, p21/WAF1, Bcl-2, Bax, Bak and Ki-67 immunoreactivity in pT1 G3 urothelial bladder carcinomas.

pT1 G3 bladder carcinomas are heterogeneous with respect to tumor recurrence and progression. Whereas some urologists treat these carcinomas by repeated transurethral resections often followed by intravesical chemotherapy or BCG instillation, others recommend cystectomy after tumor recurrence or early cystectomy after the initial diagnosis. Our goal was to determine the prognostic value of p53, p21/WAF1, Bcl-2, Bax, Bak, and Ki-67 immunoreactivity in these tumors. There were 30 patients with a new histopathological diagnosis of pT1 G3 urothelial carcinoma based on a transurethral resection specimen. Representative sections of these specimens were examined for the above markers. All patients were followed up regularly and were classified as being tumor free or having tumor recurrence or progression. The mean follow-up period was 43 months (range: 8-102 months). Twenty-five patients underwent radical cystectomy and 7 of these (28%) suffered from tumor progression and died of bladder cancer. In 5 patients, surgery was limited to a transurethral resection and 4 of these patients developed superficial tumor recurrence. There was a significant difference in tumor-free survival between patients with p53-immunoreactive (mean: 30 months) and p53-negative tumors (mean: 82 months; p = 0.0341). Bcl-2 positivity was also associated with decreased tumor-free survival (p = 0.043). The other markers had no significant prognostic impact. We conclude that p53 and Bcl-2 immunoreactivity labels the most aggressive pT1 G3 bladder carcinomas.

Biomarkers, Tumor↗