Biomedical subjects
Publications and source records attributed to J Struzyna.
Explore the source record for details and available documents.
Reverse transcription and polymerase chain reaction (RT/PCR) with primers specific for tyrosinase allow for a new method of early detection of individual melanoma cells in peripheral blood. Using this test the effect of chemo- and chemoimmunotherapy on the spread of early micrometastatic cancer cells has been evaluated. No significant correlations have been found between RT/PCR results on the one hand and stage of disease, a kind of the therapy protocol used and usage of the therapy as an adjuvant or palliative on the other hand. Thus, although the RT/PCR test for detection of circulating individual melanoma cells might help in identification of minimal residual disease in some patients, it has no application for routine staging of more advanced disease and in monitoring the response to therapy.
A new antibacterial dressing for infected wounds was prepared. The dressing was composed of a collagen membrane and collagen sponge; both biomaterials possess good tissue biocompatibility. An active antibacterial layer of limited hydrophobicity was placed between the membrane and the sponge and into the upper part of the sponge. The dressing contained gentamycin or amikacin at concentrations of 0.3 microgram/cm2 (loading level of the drug utilized during preparation of the dressing). Either the antibiotic or its concentration easily can be changed in the dressing by the manufacturer. The dressing was stable for several months. The antibiotic was released slowly from the dressing in in vitro experiments for 3 days. Antibacterial activity of the dressing was tested using a mouse wound model experimentally infected with Pseudomonas aeruginosa. Both dressings, containing either amikacin or gentamycin, reduced the number of living bacterial cells in the infected tissue almost to zero during the course of observation. The new dressing may be effective in the treatment of infected wounds in patients.
Using reverse transcription and polymerase chain reaction (PCR) with primers specific for tyrosinase the individual melanoma cells were detected in peripheral blood of patients in different stages of disease, after excision of primary lesion and prior and after chemotherapy. No relation between stage of disease (including situations with overt generalized spread of melanoma) and probability of positive PCR reaction detecting transcript for tyrosinase gene was found. Many patients in III and IV stages were negative for prolonged periods. Therefore, this method cannot be used for monitoring of all patients, because many of them are negative prior as well as after chemotherapy. With regard to the effects of therapy, the patients differed one to another and although some persons positive prior treatment became negative thereafter, a similar number of initially negative patients became positive after treatment.
An antibiotic delivery system has been developed using collagen sponge with liposome-encapsulated polymyxin B. Superficial, non-lethal infection was produced in mice by injecting Pseudomonas aeruginosa into the skin windows. Wounds were dressed with collagen sponge containing liposomal polymyxin B or containing empty liposomes (with PBS) as a control. Single dose of topically applied collagen sponge with encapsulated polymyxin B decreased bacterial cell number as compared to the control. Finally, after 8 days of experiment, the number of bacterial colonies dropped below 10(4) per biopsy. Presented polymyxin B delivery system offers potential clinical advantages.
Explore the source record for details and available documents.
The presence and concentration of selected cytokines (interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 8 (IL-8), granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were evaluated in the sera of 12 burned patients (6-90 per cent body surface area). The presence of cytokines in the sera of 20 healthy volunteers (control group) was always undetectable (< 2 pg/ml). In sera of the burned patients the concentrations of IL-4 or GM-CSF were also below the test sensitivity levels, while G-CSF and IL-6 were present throughout all the observation period and IL-8 was detectable at the onset of massive infections. The serum concentrations of G-CSF and IL-6 increased during the episodes of clinically and bacteriologically detectable infections. Their increases were, however, observable 12-24 h later than the other infection symptoms. Similar increases in G-CSF and IL-6 levels have been detected during corrective surgery (covering of granulation tissue with skin grafts). It may be concluded that serum G-CSF and IL-6 levels in burned patients may be considered as diagnostic factors, but the delays in the reaction to the massive infection do not allow us to use them for predicting the time of onset of the infection.
Local Pseudomonas aeruginosa infection of experimental wound in mice was performed. Suspension of living bacteria was injected beneath skin muscle after skin window had been made on the back of animals. On day 1, 2, 3 and 8 mice were sacrificed, biopsies were taken, number of colony forming units in muscle specimens was estimated and histological examination of skin muscle flaps was performed. The number of bacteria dropped from the very beginning of experiment to the eighth day after infection, still remaining higher than critical value of clinical infection (10(5) CFU per 1 g). Histologically, healing processes beneath skin started from the third day and on the eight day the wounds were practically healed. Developed model of infected wound may be useful to study the antibacterial agents' effectiveness.
Explore the source record for details and available documents.
The mechanism of behaviour of parameters involved in protection of the cell from oxidative damage in burn disease remains unclear. Therefore, selenium and lipid peroxide (MDA) levels, and glutathione peroxidase (GSH-Px) activities have been measured for one month in plasma of thermally injured young pigs. Immediately post-burn mean MDA level and GSH-Px activity decreased, while Se concentration increased. After 3 week lipid peroxide levels reached top concentration. Only the enzyme activity returned to initial value at the end of the study, whereas the other two parameters were below the content noted at the beginning. The Se concentration was significantly and positively correlated with GSH-Px activity, and negatively with MDA levels. The similar relationship was also showed for the enzyme and lipid peroxides. The results indicate an interesting role of the studied agents in burn disease, but still suggestions of treatment of severely burned patients with antioxidants need to be supported by detailed studies.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.