Can breast cancer Hsp 27 (Heat Shock Protein 27000) expression influence axillary lymph node status?

The expression of heat shock protein 27 (Hsp 27) in breast cancers correlates with stage of disease, the lower the stage the higher the expression, and with the presence or absence of lymph node metastases; lymph node negative patients being more likely to express Hsp 27 (P<0.04).

Quantitative and functional study of breast cancer axillary lymph nodes and those draining other human malignant tumors.

Lymphocyte functional activity from lymph nodes draining human malignancies reflects the host immune response against tumour. Breast cancer is the neoplasia with the greatest amount of identified antigens but a weak inducer of a host efficient immune response. In our study we compared the mitogen stimulated-proliferative response of cells isolated from metastases-free lymph nodes draining breast cancer (Group 1), other malignant tumours (Group 2), and those obtained from patients without malignancies (Control group). A significant decrease of the proliferative response in cells isolated from lymph nodes draining breast cancer was observed comparing it to the other groups. Quantitative analysis of B and T cells showed a higher number of B cells than T cells in Groups 1 and 2. Moreover, Group 1 presented a two fold increase of T cells compared with Group 2. Our results suggest that the immunosuppression observed in lymph nodes draining breast cancer is higher than the inmunosuppression presented in other malignant tumours and that impaired function is not correlated with the increased number of T cells.

[Biology of heat shock proteins]. / Biologia de las proteinas del shock térmico.

Hsp (Heat shock proteins) are a family of constitutive proteins of all pro and eukariotic cells that play different physiological roles: they promote the folding (acquisition of tertiary structure) assembly, translocation and secretion of newly synthesized polypeptides and participate in the removal or repairing of denatured proteins acting as molecular chaperons. This family of proteins is composed by numerous members grouped according to their molecular weight. When cells are subjected to different stresses such as hyperthermic shock, radiation, toxins, viral infections, etc., Hsp are overexpressed. In this way, they exert a cytoprotective effect, making the cells resistant to apoptosis. In humans, Hsp are overexpressed in cancer cells from ovary, endometrium, breast, prostate, digestive tract, etc. In some cases, overexpression is correlated with an unfavorable outcome because these proteins could favour metastatic disease. Some authors associate them not only with proliferation but also with differentiation of the neoplastic tissue. Recent studies show their influence in resistance to chemotherapeutic drugs. In autoimmune diseases like rheumatoid arthritis, Hsp can suppress the inflammatory response. Nevertheless, their role in the immune system has not been well established.

[Dendritic cells and their role in pathology]. / Células dendríticas y su papel en patologia.

The aim of this review is to update the knowledge on dendritic cells (CD), as potent antigen-presenting cells (APC) expressing class II major histocompatibility (MHC) antigen. The different types of DC are derived from a common bone marrow precursor. They differentiate and migrate to lymphoid and non-lymphoid tissues under the influence of diverse stimuli. After binding antigen in their periphery they move to the lymph node activating T cells. Depending on the microenvironment, DC express several surface markers and secrete cytokines such as IL-12, Il-1 and TNF alpha. DC play a role in the pathogenesis of autoimmune and viral diseases being relevant in AIDS. These cells also infiltrate human tumors where they could be involved in the induction of anti-tumor immune response. The immunostimulatory properties of DC are currently applied in DC-based therapies of melanoma and lymphoma patients.

Micoplasmas y SIDA / Mycoplasma and AIDS

El SIDA es una compleja enfermedad inducida por HIV tipo 1 y 2, que provoca una marcada inmunodeficiencia, causada fundamentalmente por la gran depleción de los linfocitos T CD4+. Las causas de esa depleción no han sido suficientemente aclaradas. En 1986, Shyh-Ching Lo conmovió a la comunidad científica con la aparente evidencia de que los micoplasmas podrían ser causa directa de la patología del SIDA. Desde ese momento diversas teorías le adjudican el papel de cofactores de la enfermedad, comensales o simples oportunistas. Los resultados de la experimentación in vitro e in vivo son controvertidos, pero sugieren un posible mecanismo que explicaría el sinergismo entre ambos organismos: el micoplasma sería parte de la flora normal del intestino y podría trasladarse a uretra, orofaringe o sangre, debido a prácticas sexuales de alto riesgo. Una vez allí, podría proliferar, amparado por desórdenes inmunológicos tempranos relacionados con HIV. Se ha especulado acerca de que diversos microorganismos, incluídos los micoplasmas, actuando como superantígenos provocarían activación crónica de los linfocitos T CD4+ y CD8+ infectados con HIV, los que responderían en forma patológica por la vía de la apoptosis. Por otra parte, los micoplasmas al inducir la producción de citoquinas influenciarían en la progresión de la enfermedad

Micoplasmas y SIDA / Mycoplasma and AIDS

El SIDA es una compleja enfermedad inducida por HIV tipo 1 y 2, que provoca una marcada inmunodeficiencia, causada fundamentalmente por la gran depleción de los linfocitos T CD4+. Las causas de esa depleción no han sido suficientemente aclaradas. En 1986, Shyh-Ching Lo conmovió a la comunidad científica con la aparente evidencia de que los micoplasmas podrían ser causa directa de la patología del SIDA. Desde ese momento diversas teorías le adjudican el papel de cofactores de la enfermedad, comensales o simples oportunistas. Los resultados de la experimentación in vitro e in vivo son controvertidos, pero sugieren un posible mecanismo que explicaría el sinergismo entre ambos organismos: el micoplasma sería parte de la flora normal del intestino y podría trasladarse a uretra, orofaringe o sangre, debido a prácticas sexuales de alto riesgo. Una vez allí, podría proliferar, amparado por desórdenes inmunológicos tempranos relacionados con HIV. Se ha especulado acerca de que diversos microorganismos, incluídos los micoplasmas, actuando como superantígenos provocarían activación crónica de los linfocitos T CD4+ y CD8+ infectados con HIV, los que responderían en forma patológica por la vía de la apoptosis. Por otra parte, los micoplasmas al inducir la producción de citoquinas influenciarían en la progresión de la enfermedad (AU)

[Mycoplasmas and AIDS]. / Micoplasmas y SIDA.

AIDS is a complex illness due to HIV type 1 and 2 infection. It is characterized by an important immunodeficiency mainly caused by depletion of CD4+ T lymphocytes. The reasons for this depletion have not been sufficiently clarified yet. In 1986, Shy Ching Lo astonished the scientific community with reported evidence concerning the direct role played by mycoplasma in the etiopathology of AIDS. Since then, different theories have pointed to mycoplasma as cofactors, commensals or opportunistic agents. Although in vivo and in vitro experiments are controversial they suggest a possible mechanism that would explain the synergism between both agents: the mycoplasma belonging to normal intestinal flora could move to urethra, oropharynx or blood due to high risk sexual practice. There it would proliferate favoured by early immunological disorders related to HIV. It has been speculated that several microorganisms including mycoplasma, acting as superantigens, could induce a chronic CD4+ and CD8+ T lymphocytes activation resulting in apoptosis of the infected lymphocytes. The release of cytokines induced by mycoplasma could influence the progression of the disease.

A simple method to eliminate mycoplasma from cell cultures.

The efficacy of several antibiotic treatments to eliminate mycoplasma from Vero cells contaminated chronically with Mycoplasma orale II were tested. Minocyclin, Kanamycin, Tylosine and Roxitromycin, at non cytotoxic concentrations, were assayed alone or in different combinations. Mycoplasma contamination was effectively eradicated without recurrence once the following regimen was applied: Incubation of contaminated cells with Tylosine (250 micrograms/ml) for 12 days followed by incubation with Minocycline (5 micrograms/ml) for 10 days. This treatment was not deleterious for cell growth, it was effective after only one application and it was successful to eradicate mycoplasma from other contaminated eukaryotic continuous cell lines.

[Prevalence of Mycoplasma orale as a contaminant of cell cultures in Argentina]. / Prevalencia de Mycoplasma orale como contaminante de los cultivos celulares en la Argentina.

Over a period of 4 years 200 cell cultures were analysed for the presence of mycoplasma. Cultures were established cell lines from different origins, namely monkey, mouse and human, hybrid cell cultures and primary cultures. The cultures belonged to various research and industrial laboratories located in different areas of the country. Seventy per cent of investigated cultures were found to be contaminated with mycoplasma using a DNA fluorescent stain. Fifty cultures, selected at random out of the contaminated cultures, were further investigated to identify the prevalent serotype. For that purpose immunofluorescent reactions were performed using immune sera raised against several mycoplasma strains routinely found among contaminated cultures. Forty one cultures were contaminated with a single type of mycoplasma, whereas in the remaining nine, two or even three serotypes were detected. Mycoplasma orale II contaminated 40% of single infected cultures, followed by M. hyorhinis and A. laidlawii-A (12% each), M. arginini (5%), M. orale III (8%), A. laidlawii-B (2%). We were unable to serotype the remaining positive cultures, because of the lack of a full battery of immune sera against all known serotypes. The prevalence of M. orale in mycoplasma contaminated cultures thus far tested, indicates that human handling would be the main source of infection. This situation could be modified by avoiding mouth pipetting and adopting good microbiological techniques.

Prevalencia de Mycoplasma orale como contaminante de los cultivos celulares en la Argentina. / [Prevalence of Mycoplasma orale as a contaminant of cell cultures in Argentina]

Over a period of 4 years 200 cell cultures were analysed for the presence of mycoplasma. Cultures were established cell lines from different origins, namely monkey, mouse and human, hybrid cell cultures and primary cultures. The cultures belonged to various research and industrial laboratories located in different areas of the country. Seventy per cent of investigated cultures were found to be contaminated with mycoplasma using a DNA fluorescent stain. Fifty cultures, selected at random out of the contaminated cultures, were further investigated to identify the prevalent serotype. For that purpose immunofluorescent reactions were performed using immune sera raised against several mycoplasma strains routinely found among contaminated cultures. Forty one cultures were contaminated with a single type of mycoplasma, whereas in the remaining nine, two or even three serotypes were detected. Mycoplasma orale II contaminated 40

of single infected cultures, followed by M. hyorhinis and A. laidlawii-A (12

each), M. arginini (5

), M. orale III (8

), A. laidlawii-B (2

). We were unable to serotype the remaining positive cultures, because of the lack of a full battery of immune sera against all known serotypes. The prevalence of M. orale in mycoplasma contaminated cultures thus far tested, indicates that human handling would be the main source of infection. This situation could be modified by avoiding mouth pipetting and adopting good microbiological techniques.

[Presence of mycoplasmas in cell cultures in Argentina]. / Presencia de micoplasmas en cultivos celulares de Argentina.

The presence of mycoplasmas in cell cultures used for virus propagation in Argentine laboratories, was studied. Samples were obtained from laboratories located in the city of Buenos Aires and provinces of Córdoba and Buenos Aires. The fluorescent stain Hoechst 33258, which specifically binds to DNA, was used for mycoplasma testing. Thirty three (65%) of 51 analyzed cell cultures (48 established lines and 3 primary cultures), were found contaminated despite that all laboratories were well equipped to work under sterile conditions. The high rate of infection observed let us conclude that the risk to work with mycoplasma contaminated cultures was not properly appreciated.

Presencia de micoplasmas en cultivos celulares de Argentina. / [Presence of mycoplasmas in cell cultures in Argentina]

The presence of mycoplasmas in cell cultures used for virus propagation in Argentine laboratories, was studied. Samples were obtained from laboratories located in the city of Buenos Aires and provinces of Córdoba and Buenos Aires. The fluorescent stain Hoechst 33258, which specifically binds to DNA, was used for mycoplasma testing. Thirty three (65

) of 51 analyzed cell cultures (48 established lines and 3 primary cultures), were found contaminated despite that all laboratories were well equipped to work under sterile conditions. The high rate of infection observed let us conclude that the risk to work with mycoplasma contaminated cultures was not properly appreciated.