Itchy Skin: A Challenging Differential Diagnosis Between Mycosis Fungoides and Sézary Syndrome.

Primary cutaneous lymphomas represent a diverse spectrum of T-cell and B-cell lymphomas with their primary skin manifestation. Among these, mycosis fungoides (MF) and Sézary syndrome (SS) represent classic forms of cutaneous T-cell lymphomas (CTCLs). This report details the case of a 67-year-old female who presented with longstanding pruritic skin lesions, initially misdiagnosed and managed as eczema. The diagnostic process ultimately revealed the presence of Sézary cells in the peripheral blood smear (PBS). The SS diagnosis was confirmed based on CD4 positivity and CD7 negativity as determined by flow cytometry. The disease was staged as IVA1 (T2N0M1B2). The patient exhibited partial improvement with oral corticosteroid therapy. This report underscores the critical importance of integrating clinical evaluation and blood findings to distinguish between MF and SS. The progression of a circulating clone signals a poor prognosis, requiring surveillance and consideration of targeted therapies to enhance patient outcomes and improve their quality of life. Early detection remains paramount in the management of these rare cutaneous lymphomas, which are associated with unique therapeutic challenges.

Anticoagulation therapy in patients with post-operative atrial fibrillation: Systematic review with meta-analysis.

BACKGROUND: Post-operative atrial fibrillation (POAF) is a relevant complication after surgery. Several studies have shown that POAF has important consequences for long-term morbidity and mortality, by increasing the risk of thromboembolic events. However, the use of oral anticoagulation (OAC) is not well established in this context. METHODS: We searched MEDLINE, CENTRAL, PsycInfo and Web of Science for clinical trials and observational studies evaluating anticoagulation vs. no anticoagulation in patients with POAF (after cardiac or non-cardiac surgery). Data were screened and extracted by two independent reviewers. We performed a random- effects model to estimate the pooled odds ratio (OR) with 95% Confidence Intervals (CI), and heterogeneity was evaluated by I2 statistics. The outcomes of interest were all-cause mortality, thromboembolic events, and bleeding events. RESULTS: Overall, 10 observational retrospective studies were included: 5 studies with 203,946 cardiac surgery POAF patients, and 5 studies with 29,566 patients with POAF after non-cardiac surgery. In cardiac surgery POAF, the OAC use was associated with lower risk of thromboembolic events (OR 0.68; 95%CI 0.47-0.96, I2 = 31%; 4 studies) and the bleeding risk was significantly increased (OR 4.30; 95%CI 3.69 to 5.02, 1 study). In non-cardiac surgery POAF, OAC did not significantly reduce the risk of thromboembolic events (OR 0.71, 95%CI 0.33-1.15; I2 = 79%; 5 studies) but was associated with increased risk of bleeding (OR 1.20, 95%CI 1.10-1.32, I2 = 0%; 3 studies). Mortality was not significantly reduced in both cardiac and non-cardiac surgery POAF. CONCLUSION: Oral anticoagulation was associated with a lower risk of thromboembolic events in patients with POAF following cardiac surgery but not in non-cardiac surgery. Bleeding risk was increased in both settings. The confidence on pooled results is at most low, and further data, namely randomized controlled trials are necessary to derive robust conclusions.

Promising Drug Targets and Compounds with Anti-Toxoplasma gondii Activity.

Toxoplasmosis is a parasitic disease caused by the globally distributed protozoan parasite Toxoplasma gondii, which infects around one-third of the world population. This disease may result in serious complications for fetuses, newborns, and immunocompromised individuals. Current treatment options are old, limited, and possess toxic side effects. Long treatment durations are required since the current therapeutic system lacks efficiency against T. gondii tissue cysts, promoting the establishment of latent infection. This review highlights the most promising drug targets involved in anti-T. gondii drug discovery, including the mitochondrial electron transport chain, microneme secretion pathway, type II fatty acid synthesis, DNA synthesis and replication and, DNA expression as well as others. A description of some of the most promising compounds demonstrating antiparasitic activity, developed over the last decade through drug discovery and drug repurposing, is provided as a means of giving new perspectives for future research in this field.

IFNγ and iNOS-Mediated Alterations in the Bone Marrow and Thymus and Its Impact on Mycobacterium avium-Induced Thymic Atrophy.

Disseminated infection with the high virulence strain of Mycobacterium avium 25291 leads to progressive thymic atrophy. We previously showed that M. avium-induced thymic atrophy results from increased glucocorticoid levels that synergize with nitric oxide (NO) produced by interferon gamma (IFNγ) activated macrophages. Where and how these mediators act is not understood. We hypothesized that IFNγ and NO promote thymic atrophy through their effects on bone marrow (BM) T cell precursors and T cell differentiation in the thymus. We show that M. avium infection cause a reduction in the percentage and number of common lymphoid progenitors (CLP). Additionally, BM precursors from infected mice show an overall impaired ability to reconstitute thymi of RAGKO mice, in part due to IFNγ. Thymi from infected mice present an IFNγ and NO-driven inflammation. When transplanted under the kidney capsule of uninfected mice, thymi from infected mice are unable to sustain T cell differentiation. Finally, we observed increased thymocyte death via apoptosis after infection, independent of both IFNγ and iNOS; and a decrease on active caspase-3 positive thymocytes, which is not observed in the absence of iNOS expression. Together our data suggests that M. avium-induced thymic atrophy results from a combination of defects mediated by IFNγ and NO, including alterations in the BM T cell precursors, the thymic structure and the thymocyte differentiation.

Toxoplasma gondii infection reduces serum progesterone levels and adverse effects at the maternal-foetal interface.

AIMS: Pregnant BALB/c mice infected with a Toxoplasma gondii type II strain were used to determine how pregnancy interferes with the development of maternal immunity to T gondii and how infection disrupts pregnancy and foetal development. METHODS: Maternal and foetal parasite loads were assessed by amplification of T gondii SAG1 using qPCR. Adverse effects of infection were evaluated on foetal-placental development by quantification of implantation units undergoing resorption and by histopathological analyses. Serum progesterone levels were quantified by immunoassay. The effect of T gondii infection on maternal immunity was determined by assessing the cellular composition of spleens by flow cytometry. RESULTS: Infected pregnant mice exhibited clinical signs of infection, inflammation and necrosis at the maternal-foetal interface and decreased serum progesterone levels. In infected mice, there was a clear effect of pregnancy and infection on macrophage cell numbers. However, no differences in the parasite load were detected between non-pregnant and pregnant mice. CONCLUSIONS: Maternal T gondii infection induced adverse effects at the maternal-foetal interface. Alterations were found in immune spleen cells, dependent on the day of pregnancy, relative to nonpregnant animals. The results obtained suggest a pregnancy-dependent mechanism during T gondii infection able to interfere with macrophage numbers.

TNF-Mediated Compensatory Immunity to Mycobacterium avium in the Absence of Macrophage Activation by IFN-γ.

Granuloma formation is a hallmark of several infectious diseases, including those caused by Mycobacterium sp These structures are composed of accumulations of inflammatory cells, and it has been shown that cytokines such as IFN-γ and TNF-α are required for granuloma assembly during M. avium infections in mice. Macrophages (MΦs) insensitive to IFN-γ (MIIG) mice have MΦs, monocytes, and dendritic cells that are unresponsive to IFN-γ. We observed that although IFN-γ-/- mice present an exacerbated infection, the same is not true for MIIG animals, where the same levels of protection as the wild-type animals were observed in the liver and partial protection in the spleen. Unlike IFN-γ-/- mice, MIIG mice still develop well-defined granulomas, suggesting that IFN-γ-mediated MΦ activation is not required for granuloma assembly. This work also shows that MIIG animals exhibit increased cell recruitment with higher CD4+ T cells numbers as well as increased IFN-γ and TNF-α expression, suggesting that TNF-α may have a role in protection and may compensate the lack of MΦ response to IFN-γ in the MIIG model. TNF-α-deficient MIIG mice (MIIG.TNF-α-/-) exhibited increased bacterial burdens when compared with MIIG mice. These results suggest that in the absence of IFN-γ signaling in MΦs, TNF-α has a protective role against M. avium.

How does toxoplasmosis affect the maternal-foetal immune interface and pregnancy?

Toxoplasma gondii is a zoonotic parasite which, depending on the geographical location, can infect between 10% and 90% of humans. Infection during pregnancy may result in congenital toxoplasmosis. The effects on the foetus vary depending on the stage of gestation in which primary maternal infection arises. A large body of research has focused on understanding immune response to toxoplasmosis, although few studies have addressed how it is affected by pregnancy or the pathological consequences of infection at the maternal-foetal interface. There is a lack of knowledge about how maternal immune cells, specifically macrophages, are modulated during infection and the resulting consequences for parasite control and pathology. Herein, we discuss the potential of T. gondii infection to affect the maternal-foetal interface and the potential of pregnancy to disrupt maternal immunity to T. gondii infection.

Targeted macrophages delivery of rifampicin-loaded lipid nanoparticles to improve tuberculosis treatment.

AIM: This work aims to develop a mannosylated nanostructured lipid carrier (NLC) loaded with rifampicin to improve tuberculosis treatment. MATERIALS & METHODS: An active targeting strategy was used and the nanoparticles were characterized. Effects on cell viability and the antimycobacterial activity of the nanoformulations were evaluated. RESULTS: The nanoparticles developed exhibited a size of about 315 nm and polydispersity <0.2. The drug encapsulation efficiency was higher than 90% and its release was sensitive to pH. The mannosylated NLCs showed efficient uptake by bone marrow derived macrophages. Further, rifampicin-loaded mannosylated NLCs were more efficient in inducing a decrease of intracellular growth of mycobacteria. CONCLUSION: The NLCs developed can be used as a promising carrier for safer and efficient management of tuberculosis.

Innate IFN-γ-Producing Cells Developing in the Absence of IL-2 Receptor Common γ-Chain.

IFN-γ is known to be predominantly produced by lymphoid cells such as certain subsets of T cells, NK cells, and other group 1 innate lymphoid cells. In this study, we used IFN-γ reporter mouse models to search for additional cells capable of secreting this cytokine. We identified a novel and rare population of nonconventional IFN-γ-producing cells of hematopoietic origin that were characterized by the expression of Thy1.2 and the lack of lymphoid, myeloid, and NK lineage markers. The expression of IFN-γ by this population was higher in the liver and lower in the spleen. Furthermore, these cells were present in mice lacking both the Rag2 and the common γ-chain (γc) genes (Rag2-/-γc-/-), indicating their innate nature and their γc cytokine independence. Rag2-/-γc-/- mice are as resistant to Mycobacterium avium as Rag2-/- mice, whereas Rag2-/- mice lacking IFN-γ are more susceptible than either Rag2-/- or Rag2-/-γc-/- These lineage-negative CD45+/Thy1.2+ cells are found within the mycobacterially induced granulomatous structure in the livers of infected Rag2-/-γc-/- animals and are adjacent to macrophages that expressed inducible NO synthase, suggesting a potential protective role for these IFN-γ-producing cells. Accordingly, Thy1.2-specific mAb administration to infected Rag2-/-γc-/- animals increased M. avium growth in the liver. Overall, our results demonstrate that a population of Thy1.2+ non-NK innate-like cells present in the liver expresses IFN-γ and can confer protection against M. avium infection in immunocompromised mice.

Lack of the Transcription Factor Hypoxia-Inducible Factor 1α (HIF-1α) in Macrophages Accelerates the Necrosis of Mycobacterium avium-Induced Granulomas.

The establishment of mycobacterial infection is characterized by the formation of granulomas, which are well-organized aggregates of immune cells, namely, infected macrophages. The granuloma's main function is to constrain and prevent dissemination of the mycobacteria while focusing the immune response to a limited area. In some cases these lesions can grow progressively into large granulomas which can undergo central necrosis, thereby leading to their caseation. Macrophages are the most abundant cells present in the granuloma and are known to adapt under hypoxic conditions in order to avoid cell death. Our laboratory has developed a granuloma necrosis model that mimics the human pathology of Mycobacterium tuberculosis, using C57BL/6 mice infected intravenously with a low dose of a highly virulent strain of Mycobacterium avium. In this work, a mouse strain deleted of the hypoxia inducible factor 1α (HIF-1α) under the Cre-lox system regulated by the lysozyme M gene promoter was used to determine the relevance of HIF-1α in the caseation of granulomas. The genetic ablation of HIF-1α in the myeloid lineage causes the earlier emergence of granuloma necrosis and clearly induces an impairment of the resistance against M. avium infection coincident with the emergence of necrosis. The data provide evidence that granulomas become hypoxic before undergoing necrosis through the analysis of vascularization and quantification of HIF-1α in a necrotizing mouse model. Our results show that interfering with macrophage adaptation to hypoxia, such as through HIF-1α inactivation, accelerates granuloma necrosis.

The Warburg effect in mycobacterial granulomas is dependent on the recruitment and activation of macrophages by interferon-γ.

Granulomas are the hallmark of mycobacterial disease. Here, we demonstrate that both the cell recruitment and the increased glucose consumption in granulomatous infiltrates during Mycobacterium avium infection are highly dependent on interferon-γ (IFN-γ). Mycobacterium avium-infected mice lacking IFN-γ signalling failed to developed significant inflammatory infiltrations and lacked the characteristic uptake of the glucose analogue fluorine-18-fluorodeoxyglucose (FDG). To assess the role of macrophages in glucose uptake we infected mice with a selective impairment of IFN-γ signalling in the macrophage lineage (MIIG mice). Although only a partial reduction of the granulomatous areas was observed in infected MIIG mice, the insensitivity of macrophages to IFN-γ reduced the accumulation of FDG. In vivo, ex vivo and in vitro assays showed that macrophage activated by IFN-γ displayed increased rates of glucose uptake and in vitro studies showed also that they had increased lactate production and increased expression of key glycolytic enzymes. Overall, our results show that the activation of macrophages by IFN-γ is responsible for the Warburg effect observed in organs infected with M. avium.

Economic evaluation of ticagrelor for secondary prevention following acute coronary syndromes.

INTRODUCTION AND OBJECTIVES: To estimate the cost-effectiveness and cost-utility of ticagrelor in the treatment of patients with acute coronary syndromes (unstable angina or myocardial infarction with or without ST-segment elevation), including patients treated medically and those undergoing percutaneous coronary intervention or coronary artery bypass grafting. METHODS: A short-term decision tree and a long-term Markov model were used to simulate the evolution of patients' life-cycles. Clinical effectiveness data were collected from the PLATO trial and resource use data were obtained from the Hospital de Santa Marta database, disease-related group legislation and the literature. RESULTS: Ticagrelor provides increases of 0.1276 life years and 0.1106 quality-adjusted life years (QALYs) per patient. From a societal perspective these clinical gains entail an increase in expenditure of €610. Thus the incremental cost per life year saved is €4780 and the incremental cost per QALY is €5517. CONCLUSIONS: The simulation results show that ticagrelor reduces events compared to clopidogrel. The costs of ticagrelor are partially offset by lower costs arising from events prevented. The use of ticagrelor in clinical practice is therefore cost-effective compared to generic clopidogrel.

[Primary and secondary outcomes in oncology clinical trials: definitions and uses]. / Indicadores (outcomes) primários e secundários em ensaios clínicos oncológicos: definição e usos.

INTRODUCTION: The proof of efficacy from a therapeutic intervention in oncology must be defined through well conducted clinical trials. One of the most important methodological issue is the outcome selection needed to calculate measures of association allowing definition of clinical efficacy. MATERIAL AND METHODS: We designed a narrative revision based on some of the international regulatory instructions from drug agencies, as well as consensus papers from scientific oncology societies, listing and critically assessing each outcome used in oncology clinical trials. RESULTS: We identified as being the most important outcomes in oncology trials the overall survival, the progression free survival/ disease-free survival, the toxicity, the quality of life/patient-reported outcomes and the objective response rate. DISCUSSION: The selection of the primary outcome must be based on therapeutic efficacy as well as toxicity, expected survival, alternative drug regimens and even disease prevalence. CONCLUSION: The selection of efficacy outcomes for clinical trials in oncology is very important and its selection must be well justified, and depends on the type of disease, the patients and the drug being studied.

Introdução: A prova de eficácia de uma intervenção terapêutica em oncologia consegue-se através de ensaios clínicos rigorosamente conduzidos. Um dos factores metodológicos mais importantes é a selecção de indicadores clínicos de eficácia (outcomes), necessários ao cálculo das chamadas medidas de associação que permitem a definição de eficácia terapêutica. Material e Métodos: Foi feita uma revisão narrativa baseada em alguns dos documentos de agências reguladoras internacionais, assim como documentos de consenso entre as sociedades científicas oncológicas, procurando listar e avaliar criticamente cada um dos indicadores utilizados em ensaios clínicos oncológicos. Resultados: Identificaram-se como indicadores mais importantes a sobrevivência global, a sobrevivência livre de progressão/sobrevivência livre de doença, a toxicidade/qualidade de vida e taxa objectiva de resposta tumoral. Discussão: A selecção do outcome primário deve basear-se no conceito de eficácia terapêutica, mas também na toxicidade relativa da terapêutica experimental, na sobrevivência esperada após progressão da doença, na existência de fármacos alternativos já estudados com indicações idênticas e até a prevalência da patologia em causa. Conclusão: A selecção de indicadores em ensaios clínicos oncológicos reveste-se de especial importância e a sua selecção deve ser bem fundamentada, dependendo da doença, dos doentes e do fármaco em estudo.

Steroidal aromatase inhibitors inhibit growth of hormone-dependent breast cancer cells by inducing cell cycle arrest and apoptosis.

Different hormonal therapies are used for estrogen receptor positive (ER(+)) breast cancers, being the third-generation of aromatase inhibitors (AIs), an effective alternative to the classical tamoxifen. AIs inhibit the enzyme aromatase, which is responsible for catalyzing the conversion of androgens to estrogens. In this study, it was evaluated the effects of several steroidal AIs, namely 3ß-hydroxyandrost-4-en-17-one (1), androst-4-en-17-one (12), 4α,5α-epoxyandrostan-17-one (13a) and 5α-androst-2-en-17-one (16), on cell proliferation, cell cycle progression and cell death in an ER(+) aromatase-overexpressing human breast cancer cell line (MCF-7aro). All AIs induced a decrease in cell proliferation and these anti-proliferative effects were due to a disruption in cell cycle progression and cell death, by apoptosis. AIs 1 and 16 caused cell cycle arrest in G0/G1, while AIs 12 and 13a induced an arrest in G2/M. Moreover, it was observed that these AIs induced apoptosis by different pathways, since AIs 1, 12 and 13a activated the apoptotic mitochondrial pathway, while AI 16 induced apoptosis through activation of caspase-8. These results are important for the elucidation of the cellular effects of steroidal AIs on breast cancer cells and will also highlight the importance of AIs as inducers of apoptosis in hormone-dependent breast cancers.

Apoptosis and autophagy in breast cancer cells following exemestane treatment.

Aromatase inhibitors (AIs), which block the conversion of androgens to estrogens, are used for hormone-dependent breast cancer treatment. Exemestane, a steroidal that belongs to the third-generation of AIs, is a mechanism-based inhibitor that binds covalently and irreversibly, inactivating and destabilizing aromatase. Since the biological effects of exemestane in breast cancer cells are not totally understood, its effects on cell viability, cell proliferation and mechanisms of cell death were studied in an ER-positive aromatase-overexpressing breast cancer cell line (MCF-7aro). The effects of 3-methyladenine (3-MA), an inhibitor of autophagy and of ZVAD-FMK, an apoptotic inhibitor, in exemestane treated cells were also investigated. Our results indicate that exemestane induces a strong inhibition in MCF-7aro cell proliferation in a dose- and time-dependent manner, promoting a significant cell cycle arrest in G(0)/G1 or in G(2)/M phases after 3 and 6 days of treatment, respectively. This was accompanied by a decrease in cell viability due to activation of cell death by apoptosis, via mitochondrial pathway and the occurrence of autophagy. Inhibition of autophagy by the autophagic inhibitor, 3-MA, resulted in a reduction of cell viability and activation of caspases. All together the results obtained suggest that exemestane induced mitochondrial-mediated apoptosis and autophagy, which act as a pro-survival process regulating breast cancer cell apoptosis.

Cytotoxicity and genotoxicity of chitooligosaccharides upon lymphocytes.

Two COS mixtures and a low molecular weight chitosan (LMWC) were tested for potential cytotoxicity and genotoxicity upon human lymphocytes. Genotoxicity was evaluated in vitro by cytokinesis-blocked micronucleus and alkaline comet assays, while cytotoxicity was assessed by flow cytometry analysis. Our results suggest that COS do not exhibit any genotoxicity upon human lymphocytes, independently of MW or concentration. However, above 0.07mg/mL COS induced strong cytotoxic effects. According to the concentration used, such cytotoxicity will induce cell death, essentially by necrosis (>0.10mg/mL) and/or apoptosis (<0.10mg/mL). The level of necrosis/apoptosis induced by high COS concentrations, suggests a promising use as apoptosis inducers in specific cancer situations.

The burden of disease and the cost of illness attributable to alcohol drinking--results of a national study.

BACKGROUND AND AIMS: The World Health Organization estimated that 3.2% of the burden of disease around the world is attributable to the consumption of alcohol. The aim of this study is to estimate the burden of disease attributable to alcohol consumption in Portugal. METHODS: Burden and costs of diseases attributable to alcohol drinking were estimated based on demographic and health statistics available for 2005, using the Disability-Adjusted Life Years (DALY) lost generated by death or disability. RESULTS: In Portugal, 3.8% of deaths are attributable to alcohol (4,059 of 107,839). After measuring the DALY generated by mortality data, the proportion of disease attributable to alcohol was 5.0%, with men having 5.6% of deaths and 6.2% of disease burden, while female figures were, respectively, 1.8 and 2.4%. Considering the sum of death and disability DALYs, liver diseases represented the main source of the burden attributable to alcohol with 31.5% of total DALYs, followed by traffic accidents (28.2%) and several types of cancer (19.2%). As for the cost of illness incurred by the health system, our results indicate that 95.1 millions euros are attributable to alcohol-related disease admissions (liver diseases, cancer, traffic accidents, and external causes) while the ambulatory costs of alcohol-related diseases were estimated in 95.9 million euros, totaling 191.0 million euros direct costs, representing 0.13% of Gross Domestic Product and 1.25% of total national health expenditures. An alternative analysis was carried out using higher consumption levels so as to replicate aggregate alcohol consumption statistics. In this case, DALYs lost increased by 11.7% and health costs by 23%. CONCLUSION: Our results confirm that alcohol is an important health risk factor in Portugal and a heavy economic burden for the health system, with hepatic diseases ranking first as a source of burden of disease attributable to alcohol.

The burden of disease attributable to smoking in Portugal.

The World Health Organization's (WHO) 2002 Annual Report estimated that about 14% of the burden of disease in wealthier countries is attributable to smoking. Smoking related diseases include cardiovascular diseases, cancer and respiratory diseases. This paper presents an estimate of the burden of disease attributable to smoking in Portugal. The estimates are based on the Portuguese demographic and health statistics available for 2005. The most important conclusion of the analysis is that 11.7% of deaths in Portugal are attributable to smoking. If we use disability adjusted life years (DALYs) to measure the burden of disease, we find that 11.2% of death DALYs in Portugal is attributable to smoking. The gender distribution of this amount is very unequal; 15.4% of the male burden of disease and 17.7% of all male deaths can be attributed to smoking, but only 4.9% of the female burden of disease and 5.2% of all female deaths. These estimates are higher than death estimates previously available (Peto et al. 2006); 14% in men and only 0.9% in women. This paper also presents estimates of the burden of reducible disease, that is, the reduction in mortality and DALYs that would occur if all current smokers quit and thus experienced the mean risk of ex-smokers, which is lower than for current smokers but typically not as low as for never-smokers. Our estimates are that the burden of disease would decrease by 5.8% (7.8% in men and 2.8% in women), and that deaths would decrease by 5.8% as well (with an 8.5% and 2.9% decrease in men and women, respectively). The paper also includes estimates of the burden of disease generated by smoking related disability. Smoking related illnesses generated 121,643 DALYs, 72,126 (59%) of which are attributable to smoking and 12,417 would be reducible if all smokers were to quit.

New steroidal aromatase inhibitors: suppression of estrogen-dependent breast cancer cell proliferation and induction of cell death.

BACKGROUND: Aromatase, the cytochrome P-450 enzyme (CYP19) responsible for estrogen biosynthesis, is an important target for the treatment of estrogen-dependent breast cancer. In fact, the use of synthetic aromatase inhibitors (AI), which induce suppression of estrogen synthesis, has shown to be an effective alternative to the classical tamoxifen for the treatment of postmenopausal patients with ER-positive breast cancer. New AIs obtained, in our laboratory, by modification of the A and D-rings of the natural substrate of aromatase, compounds 3a and 4a, showed previously to efficiently suppress aromatase activity in placental microsomes. In the present study we have investigated the effects of these compounds on cell proliferation, cell cycle progression and induction of cell death using the estrogen-dependent human breast cancer cell line stably transfected with the aromatase gene, MCF-7 aro cells. RESULTS: The new steroids inhibit hormone-dependent proliferation of MCF-7aro cells in a time and dose-dependent manner, causing cell cycle arrest in G0/G1 phase and inducing cell death with features of apoptosis and autophagic cell death. CONCLUSION: Our in vitro studies showed that the two steroidal AIs, 3a and 4a, are potent inhibitors of breast cancer cell proliferation. Moreover, it was also shown that the antiproliferative effects of these two steroids on MCF-7aro cells are mediated by disrupting cell cycle progression, through cell cycle arrest in G0/G1 phase and induction of cell death, being the dominant mechanism autophagic cell death. Our results are important for the elucidation of the cellular effects of steroidal AIs on breast cancer.

Gamma interferon-induced T-cell loss in virulent Mycobacterium avium infection.

Infection by virulent Mycobacterium avium caused progressive severe lymphopenia in C57BL/6 mice due to increased apoptosis rates. T-cell depletion did not occur in gamma interferon (IFN-gamma)-deficient mice which showed increased T-cell numbers and proliferation; in contrast, deficiency in nitric oxide synthase 2 did not prevent T-cell loss. Although T-cell loss was IFN-gamma dependent, expression of the IFN-gamma receptor on T cells was not required for depletion. Similarly, while T-cell loss was optimal if the T cells expressed IFN-gamma, CD8(+) T-cell depletion could occur in the absence of T-cell-derived IFN-gamma. Depletion did not require that the T cells be specific for mycobacterial antigen and was not affected by deficiencies in the tumor necrosis factor receptors p55 or p75, the Fas receptor (CD95), or the respiratory burst enzymes or by forced expression of bcl-2 in hematopoietic cells.