Stability of antibacterial modification of nanofibrous PA6/DTAB membrane during air filtration

Stable antimicrobial nanofibrous membrane for air filtration based on polyamide 6 (hereafter PA6) modified by 1-dodecyltrimethylammonium bromide (DTAB) has been prepared by electrospinning using one-step technology, i.e. with modifying antimicrobial agent dissolved in spinning solution. Stability of antibacterial membrane function has been tested by air-blowing test to prove the permanency of chemical composition and antibacterial activity. X-ray diffraction, high-resolution scanning electron microscopy (HRSEM) revealed the effect of modifying agent on structure and morphology of PA6 nanofibres. X-ray photoelectron spectroscopy, electrokinetic analysis and antibacterial tests proved the stability of chemical composition and antibacterial activity after air-blowing tests. Special air-blowing device has been constructed for this purpose. The results prove the applicability so prepared membrane for a long-term air-conditioning.

Nanofibers prepared by needleless electrospinning technology as scaffolds for wound healing

Electrospun gelatin and poly-ε-caprolactone (PCL) nanofibers were prepared using needleless technology and their biocompatibility and therapeutic efficacy have been characterized in vitro in cell cultures and in an experimental model of a skin wound. Human dermal fibroblasts, keratinocytes and mesenchymal stem cells seeded on the nanofibers revealed that both nanofibers promoted cell adhesion and proliferation. The effect of nanofibers on wound healing was examined using a full thickness wound model in rats and compared with a standard control treatment with gauze. Significantly faster wound closure was found with gelatin after 5 and 10 days of treatment, but no enhancement with PCL nanofibers was observed. Histological analysis revealed enhanced epithelialisation, increased depth of granulation tissue and increased density of myofibroblasts in the wound area with gelatin nanofibers. The results show that gelatin nanofibers produced by needleless technology accelerate wound healing and may be suitable as a scaffold for cell transfer and skin regeneration.

[Cloning--ethical aspects]

Ethical problems related to cloning are discussed on three model situations: cloning of human beings (for example by utilizing the techniques of embryo splitting or nuclear transfer), use of embryonic cells in cloning techniques and cloning of nonembryonic cells. The first situation is strictly condemned, the second has been examined up present (it should be condemned as well) and the third is--under certain conditions--fully acceptable. The issue is discussed from the point of view of relevant Council of Europe documents as well.

[Ethical aspects of treatment in patients with advanced oncologic diseases]

Ethical aspects of treatment are discussed from the aspect of medical objectives and the doctor-patient relationship. The authors draws attention to various dangers of incorrect approaches which may ensue for the patient: unnecessary and excessively burdening antitumourous treatment, inadequate treatment--in particular of pain, queer views on palliative treatment, a paternalistic approach of the physician with insufficient respect for the patient's wishes, inadequate information provided to the patient, "abuse" of patients for different experimental treatments etc. The author discusses in detail the double effect principle and draws attention to classification of means into ordinary and extraordinary with regard to the patient's own evaluation.

Genetic susceptibility to malignant diseases--ethical issues. Minireview

Ethical problems connected with genetic testing with the intention of the measurement of the susceptibility or predisposition to malignant tumors are presented (respect for autonomy, beneficence, nonmaleficence, confidentiality, privacy, veracity and truth-telling, informed consent, right to know, right not to know, informational self-determination, etc.). Various aspects dealing with ethics of screening and research projects involving human subjects are discussed as well.

[Psychology and ethics of care of oncology patients]

The author discusses the necessity of perception of the uniqueness of oncological patients and the necessity to treat all their dimensions (physical, social, mental and spiritual). She analyzes the concept of total pain according to Cecilia Saunders who discusses the mentioned dimensions of man. Total pain is made up of mutually linked components which are difficult to separate: physical pain, social pain, emotional pain, and spiritual pain. Contemporary alarming statistics provide evidence that in many patients suffering is not alleviated correctly. One of the important reasons of failure is also failure of health workers as regards knowledge of the complexity of suffering.

[The attitude of students regarding human dignity]

Contemporary secular thinking concerning human dignity is discussed. The opinions of a great majority of 523 students (Medical Faculty, Masaryk University, Brno) do not agree with the suggestion that suffering and terminal illness can rob the patient of his dignity (as, e.g. Motion of European Parliament for a resolution on care of the terminally ill in 1991 suggested). On the contrary the students claim that it is necessary to fight against such possible feeling of patients and that this feeling might be brought about by disrespectful behaviour of medical staff. The question "Which ethics for bioethics" is discussed as well. Because of the existing pluralism in the actual moral and philosophical situation the values and principles which are proposed in bioethics are extremely diversified. The necessity of a philosophical point of view that justifies respect for human life and its dignity in all its aspects is pointed out.

HLA-DR antigen expression on melanoma metastases and the course of the disease

Melanoma cells freshly isolated from regional lymph node metastases of 59 stage II malignant melanoma patients were analyzed by indirect immunofluorescence staining with monoclonal antibody TAL 1B5, detecting the HLA-DR alpha chain. The expression of HLA-A,B,C antigens, using antibody W6/32, was also investigated in 45 of these cases. There were no substantial differences in the course of the disease with respect to the percentage of positive cells. In 13 malignant melanoma patients two to four simultaneous and/or successive metastases (both locoregional and distant-subcutaneous) were analysed for HLA-DR. With simultaneous metastases (7 cases) the percentage of HLA-DR-positive cells was mostly very similar, and in no case was there more than 25% variation. As to successive metastases (9 cases) the percentage of HLA-DR-positive cells remained practically unchanged or decreased during the course of the disease.

Is cancer a macrophage-mediated autoaggressive disease?

As part of their physiological functions macrophages secrete various products that influence tissue environment. They can also secrete tumour growth promoting substances and it is highly probable that they help to establish tumour supporting fibrovascular stroma. Macrophages may fuse with other cells (including neoplastic cells) and many malignant properties of these hybrids or of their progeny may be maintained by the macrophage genome. In addition processes that occur after fusion might be important in inducing malignant transformation, especially when fusion has occurred with initiated cells. Superficial spreading melanoma is an example that is in keeping with the hypothesis of cell fusion.

Expression of HLA-DR antigens on tumour cells does not contribute to skin reactivity to autologous cholesteryl hemisuccinate (CHS)-treated tumour cells in patients with metastatic melanoma

Skin tests with autologous cholesteryl hemisuccinate (CHS)-treated and untreated cells were performed in ten metastatic melanoma patients. In the majority of cases evident reaction was noted with CHS-treated cells (9/10) while the reaction with untreated cells was mostly negative (7/10). Tumour cell suspensions used for skin tests were characterized for reactivity with monoclonal antibody TAL 1B5 detecting the HLA-DR alpha chain. There were no differences between CHS-treated and untreated cells with respect to HLA-DR expression and no correlation was found between grade of skin reaction to CHS-treated cells and the proportion of HLA-DR positive cells in the injected cell sample.

Skin tests with autologous cholesteryl hemisuccinate treated tumour cells in cancer patients

Skin tests with autologous irradiated tumour cells were performed in 20 malignant melanoma, 7 breast and 6 ovarian cancer patients. In the majority of cases evident reaction was noted with cholesteryl hemisuccinate (CHS)-treated cells while the reaction with untreated cells was mostly negative. No correlation was found between this reactivity and the ability of patients to be sensitized to DNCB and to their reactivity to PPD. No correlation was found between reactivity to CHS-treated tumour cells and the stage and course of the disease.

Leukocyte adherence inhibition responses obtained with various tumor extracts in breast cancer patients

Leukocyte adherence inhibition (LAI) assay was employed to detect cell-mediated immune response in breast cancer patients of clinical stages I and II. Twenty-one breast cancer extracts were screened in 232 breast cancer patients and 343 healthy persons. The activity of individual extracts differed remarkably. Overall, LAI response was 58.6% (136/232) correct and 18.9% (65/343) false positive. Fifteen extracts were not suitable from the clinical point of view. Only two extracts gave a constantly high rate of tumor-specific LAI-positive values in breast cancer patients, ie, 83.3% (25/30) and low percentage of false positive results in controls, ie, 4% (2/50). A further study dealt with the possible relation between the activity of extracts (expressed in percentage of positive LAI results in the tumor group) and histology of primary tumor of patients whose tumor tissue was used for extraction. This relationship could not be proven statistically. We investigated also whether the percentage of correct LAI responses in breast cancer patients could be affected by histological agreement or disagreement (grading and node involvement) between primary tumor of extract donor and primary tumor of patients tested. No significant relationship was found in this respect.

Immunoelectrophoretic abnormality in Sera from patients with different malignant diseases

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