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Biomedical subjects

K Sikorski

Publications and source records attributed to K Sikorski.

8 recordsLinked to original sources
PubMed2006

Osteoblast response to the elastic strain of metallic support.

It is known that metallic elements of joint endoprostheses undergo elastic strain due to their mechanical function. This is one of the factors which may be responsible for the loosening of endoprostheses. Since mechanisms involved in it remain unclear, it seems valuable to verify if cells responsible for bone regeneration are affected by a strain of the implant. Our experiment examines the influence of elastic strain applied to Ti6Al4V samples on osteoblasts cultured on their surface in vitro. Human bone-derived cells are observed in contact with metallic plates. Titanium alloy was chosen as a support since it is one of the most commonly used materials for stems in joint endoprostheses. Cyclic elastic deformation of 0.1% was applied to the support once daily for 7 days. Two thousand cycles were applied each time. Samples which were not subject to strain served as control. After the observation period XTT assay was performed, alkaline phosphatase activity as well as osteocalcin concentration and nitric oxide secretion were determined and compared with the results obtained in the control group. It was found that the number of viable cells in the mechanically stimulated population was significantly higher than in control, while both alkaline phosphatase activity and osteocalcin concentration were significantly lower in the experimental group. Nitric oxide secretion was found in the culture which was subject to elastic strain, but not in the control. The possible clinical implication is that elastic strain of the metallic endoprostheses may influence osteoblasts which are in contact with the implant in vivo.

Adolescent↗
PubMed1999

Calcitonin driven v-Ha-ras induces multilineage pulmonary epithelial hyperplasias and neoplasms.

We initiated a transgenic model for primary pulmonary neuroendocrine cell (PNEC) hyperplasia/neoplasia using v-Ha-ras driven by the neural/neuroendocrine (NE)-specific calcitonin promoter (rascal). Previously, we showed that nitrosamine treated rodents develop PNEC hyperplasia but non-NE lung tumors, with variable outcomes presumably reflecting ras activation in multiple cell lineages. Interestingly, all rascal transgenic mouse lineages develop hyperplasias of NE and non-NE cells but mostly non-NE lung carcinomas, with rascal mRNA in differentiated PNECs and tumor cells. Analyses of embryonic lung demonstrate rascal mRNA in undifferentiated epithelium, consistent with expression in a common pluripotent precursor cell. These unexpected observations indicate that v-Ha-ras can lead to both NE and non-NE hyperplasia/neoplasia in vivo, opening new avenues for studies of lung carcinogenesis.

Adenocarcinoma↗
PubMed1997

Bone-implant interface, objectivization of X-ray microanalysis.

Several techniques of the bone-implant interface uncovering in the proper way for X-ray microanalysis, were tested. The obtained results confirmed that the method of sample preparation has significantly influenced the results of investigation. The mechanical polishing, which is routinely used for preparation of surfaces to the X-ray microanalysis, introduces artifacts. Cutting by means of microtome, in the case of brittle implants, and sawing by utilizing diamond saw, in the case of metallic ones, were indicated as the optimal methods. Cleaning of the samples in the ultrasonic cleaner before covering them with conductive layer is required.

Animals↗
PubMedDate not supplied

[A case of hemorrhagic pancreonecrosis successfully treated by repeated laparotomies using an Ethizip zipper].

A 26-year-old man is reported in whom during acute pancreatitis haemorrhagic necrosis developed with formation of abscesses in the organ. The patient was successfully treated with repeated multiple laparotomies using an Ethizip zipper. The total time of treatment was 87 days. The zipper was sutured-in during the first operation on the 11th day of hospitalization, and was removed after 28 days after another three explorations of the abdominal cavity. The patient had thus 5 operations, including one for removal of the zipper.

Abdominal Muscles↗