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Biomedical subjects

N Kastner

Publications and source records attributed to N Kastner.

4 recordsLinked to original sources
PubMed2003

[Surgical therapy of pelvis and spine in primary malignant bone tumors].

Despite standardization of surgical treatment of primary malignant tumors of the pelvis and spine, prognosis in these centrally located tumors still is inferior compared to those located in the extremities. This fact may be attributed to delayed diagnosis in many cases and the resulting increase in tumor volume as well as to difficulties of resection due to the anatomical situation. The frequency of local recurrence after resection of primary malignant tumors is reported to be between 4 and 41% and the 5-year survival rate below 40%. Whereas the latter has remained almost unchanged during the past 20 years, amputation has been replaced by limb-salvage surgery except for a minimal amount of less than 10%. For reconstruction, biological techniques are increasingly preferred to endoprosthetic replacement or use of bulk allografts because of the high complication rate. Even in the spine wide resections are feasible provided at least one lamina is healthy in order to prepare and save the neural structures without touching the tumor. Compared to the widely used technique of curettage, en bloc resection may provide a significantly better oncologic result with respect to local tumor control. Failure of the dorsoventral stabilization with delayed union is the most frequent complication of these challenging procedures. In order to improve the long-term prognosis of these groups of patients in the future, early diagnosis and immediate admission to a specialized tumor service has to be attempted.

Adolescent↗
PubMed2000

Primary human bone cultures from older patients do not respond at continuum levels of in vivo strain magnitudes.

Osteoporosis is characterized by excessive loss of bone mass, while exercise is believed to maintain or enhance bone mass. Since exercise marginally affects osteoporosis, we wondered whether bone cells from osteoporotic patients would fail to respond to strain. Primary human bone-like cultures were obtained from females over age 60 with hip arthroplasty procedures performed for either osteoporotic fracture (n = 8) or non-osteoporotic osteoarthrosis (n = 5). Cultures (96,000 cell/cm2) were strained in rectangular optically clear silastic wells. Three periods of uniaxial substratum strain (1000 micro-strain, 1 Hz, 10,000 cycles, sine wave) were provided every 24 h using a four-point bending, computer-controlled device. Results at a frequency of 1 Hz were compared to cultures exposed to 20 Hz with bone cells derived from one osteoarthritic subject. Alterations in protein level expression of bone-related proteins were determined using a semi-quantitative confocal approach along with enzyme (alkaline phosphatase) activity and enzyme mRNA copy number using cRNA RT-PCR. Strain did not alter levels of bone-related protein levels, enzyme activity, or steady state copy number per cell in response to strain in either group. Strained cultures from osteoporotic patients exhibited little variation from unstrained controls, while individual cultures from osteoarthritic patients exhibited increases in one protein or the other. The results suggest that bone cells from older individuals may not be responsive to continuum levels of strain anticipated with vigorous activity.

Aged↗
PubMed1997

Giardiasis: a histologic analysis of 567 cases.

BACKGROUND: The histopathology of the upper and lower gastrointestinal tract of patients with giardiasis as shown by endoscopy with biopsy is ill-defined. We therefore report on 567 cases observed in our institution. METHODS: A retrospective analysis of all cases with giardiasis observed between 1988 and 1994 was performed. RESULTS: On histologic slides trophozoites were found in duodenal (82.5%) and jejunal (2.1%) mucosa and also in gastric antral (8.7%) and ileal mucosa (12.1%) but rarely in the colon (0.4%). An entirely normal light-microscopic appearance of the duodenal mucosa was found in 462 cases (96.3%). Mild villous shortening and mild inflammation of the lamina propria were observed in duodenal mucosa in 18 subjects (3.7%). In jejunal, ileal, gastric, and colonic mucosa, no Giardia-specific histologic changes were identified. There was a clear male predominance with 347 (61.2%) males and 220 (38.8%) females. Mean age, which was comparable in males and females, was 49.5 +/- 17 years (range, 3-95 years). In 252 Giardia-positive cases gastric biopsy specimens were available, and showed Helicobacter pylori-associated gastritis in 57.8%, reactive gastritis in 10.3%, normal mucosa in 12.9%, chronic atrophic gastritis of the body in 2.9%, and other forms of gastritis in 16.1%. CONCLUSIONS: This study shows that the histology of the small-bowel mucosa is inconspicuous in most subjects with giardiasis. A search for the parasite must therefore be made in all biopsy samples obtained from this area. Furthermore, giardiasis was not associated with a particular gastric disease, such as chronic atrophic gastritis of the body.

Adolescent↗