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Biomedical subjects

K Sikora

Publications and source records attributed to K Sikora.

At least 73 records · Page 4Linked to original sources
PubMed1991

Immune modulation and cancer.

The concept that the immune system is involved in defence against cancer goes back nearly a hundred years. Despite increased sophistication in our analysis of the immune response it has proven difficult to demonstrate a powerful role of the immune system in either the prevention or treatment of cancer. Animal data has consistently and clearly shown that the immune system can identify and reject experimental tumours. In patients the data is more conflicting. The isolation of individual cytokines which stimulate specific components of the immune response and have a anti-cancer effect does suggest, however, that as we learn more about the interaction between immunity and cancer, novel methods for the diagnosis and therapy of cancer will be developed.

Antigens, Neoplasm↗
PubMed1991

New therapeutic modalities for cancer.

A review is given on new biological approaches to cancer therapy based on knowledge concerning interferons, interleukins. LAK-cells, tumour-infiltrating lymphocytes, tumour necrosis factor, colony-stimulating factors, monoclonal antibodies and oncogenes. There are many potential permutations for the application of biological therapy for cancer. One of the most important developments has been the increased understanding of the molecular mechanisms of malignancy through which biological manipulation can be tailored to an individual tumour. Although current clinical studies are not demonstrating high response rates they may well be analogous to the advances seen with chemotherapy in its early days. As yet only relatively small numbers of patients have had access to, or been suitable for, treatment. With further refinements in production, administration, and an increase in the specificity of treatment, the possibility of curing metastatic solid tumours may become a reality.

Antibodies, Monoclonal↗
PubMed1991

Preoperative radiotherapy combined with resection of squamous cell carcinoma of the mid-thoracic oesophagus. Does a histopathological malignancy grading system assess actual survival?

The aim of our study was to assess the reproducibility of the findings of Hambraeus et al. In their group of patients with squamous cell carcinoma of the oesophagus who underwent preoperative radiotherapy and resection, the histopathological malignancy grading score system was found to predict survival. We studied nine patients with squamous cell cancer of the mid-thoracic oesophagus, who had received radiotherapy followed by surgery and survived over 12 months. We did not confirm the prognostic value of the histopathological malignancy grading score system.

Aged↗
PubMed1990

The partial purification and characterization of GnRH-like activity from prostatic biopsy specimens and prostatic cancer cell lines.

We have investigated the possibility of the secretion of gonadotrophin-releasing-hormone (GnRH)-like peptides by prostatic cancer cells in culture and their presence in cytosolic preparations from human prostatic biopsy specimens. A GnRH-specific radioimmunoassay showed GnRH-like activity in concentrated cytosolic preparations and conditioned media from DU 145, an androgen-insensitive human prostatic cell line and from LNCaP, an androgen-responsive prostatic cancer cell line. GnRH immunoreactivity in culture media correlated directly with cell numbers. HPLC demonstrated that this GnRH-like material co-migrated with synthetic GnRH. This homology between synthetic GnRH and partially purified prostatic GnRH was confirmed following V8 protease and trypsin digestion which resulted in similar alterations in HPLC characteristics. The mean content of GnRH-like activity/g specimen tissue was significantly more in malignant tissue (88.5 +/- 80.5 fmol) than in benign (29.6 +/- 22 fmol), though more specimens of benign tissue were positive (37/54) than malignant tissue (6/22). This observation, taken with an earlier finding of GnRH-specific receptors in a hormone-sensitive cell line and human cancer specimens provides supportive evidence for the autocrine hypothesis of cell regulation.

Gonadotropin-Releasing Hormone↗
PubMed1990

Prescription for a system.

Health authorities' drug budgets are large and difficult to control. Alan Willson and colleagues outline the system requirements for audit, resource management and costing reports.

Clinical Pharmacy Information Systems↗
PubMed1990

Oncoprotein stability after tumour resection.

The means by which oncogenes and their products activate malignant transformation are currently under intense investigation. However, published papers on experiments using human tumour material do not always report in detail their methods of collection or storage of the specimens. In order to assess the stability of oncogene encoded proteins following collection or storage of human tumour biopsies, we have examined the rate of decay of the c-myc, neu and EGF-receptor proteins. Solid tumours, containing amplified copies of each oncogene, were established in nude mice and the stability of the oncogene protein in portions of each tumour, left in phosphate buffered saline at room temperature for varying time intervals, was examined by immunoblotting. Intact EGF-receptor and neu oncoproteins were present even after 24 h under these conditions while the c-myc protein was apparently rapidly degraded after 20 min. These data demonstrate that oncogene products decay at different rates after tumour resection and that collection of human biopsies should take this into account in order to provide the basis for consistent measurements of protein expression.

Animals↗
PubMed1990

The effects of gonadotrophin releasing hormone analogues in prostate cancer are mediated through specific tumour receptors.

We have investigated the possibility of a direct regulatory effect of gonadotrophin releasing hormone (GnRH) analogues on prostatic cancer cell growth. Here we report high affinity binding (Kd = 50 nM) of a GnRH analogue resulting in biphasic growth modulation of the human androgen-sensitive prostatic cancer cell line LNCaP. In contrast, the human androgen-insensitive prostatic cancer cell line DU145 showed low-affinity (Kd = 10 microM) binding without any biological response to the GnRH analogue. A GnRH-specific radioimmunoassay demonstrated GnRH-like immunoreactivity in the concentrated culture medium from both cell lines. Seventy-six human benign and malignant tumours were assayed following surgical resection. Nineteen of 22 (86%) malignant tumours and 49 of 54 (91%) benign tumours, exhibited high affinity GnRH-analogue binding. Fourteen of 19 (74%) malignant tumours and 17 of 49 (35%) benign tumours exhibiting high affinity binding contained GnRH-like immunoreactivity, suggesting that this system may be involved in prostatic epithelial cell growth in vivo.

Buserelin↗