Tuberculosis in patients treated with tumor necrosis factor-alpha antagonists living in an endemic area. Is the risk worthwhile?

Tumor necrosis factor alpha antagonists (TNFA) are biological agents to treat chronic inflammatory and autoimmune diseases. However, their use is associated with an increased rate of tuberculosis, endemic mycoses, and intracellular bacterial infections. Since tuberculosis is moderately to highly endemic in Colombia, the risk of these infections in patients treated with TNFAs may be higher than previously reported in Colombia. Recently, four patients have developed tuberculosis during TNFA therapy. Tuberculosis appeared between 3 to 24 months after initiation of TFNA therapy and was independent of previous tuberculin skin test status. A review of the relevant literature and recommendations are presented as guides for surveillance and prophylaxis on a country-wide basis.     

Fungal ribotoxins: molecular dissection of a family of natural killers

RNase T1 is the best known representative of a large family of ribonucleolytic proteins secreted by fungi, mostly Aspergillus and Penicillium species. Ribotoxins stand out among them by their cytotoxic character. They exert their toxic action by first entering the cells and then cleaving a single phosphodiester bond located within a universally conserved sequence of the large rRNA gene, known as the sarcin-ricin loop. This cleavage leads to inhibition of protein biosynthesis, followed by cellular death by apoptosis. Although no protein receptor has been found for ribotoxins, they preferentially kill cells showing altered membrane permeability, such as those that are infected with virus or transformed. Many steps of the cytotoxic process have been elucidated at the molecular level by means of a variety of methodological approaches and the construction and purification of different mutant versions of these ribotoxins. Ribotoxins have been used for the construction of immunotoxins, because of their cytotoxicity. Besides this activity, Aspf1, a ribotoxin produced by Aspergillus fumigatus, has been shown to be one of the major allergens involved in allergic aspergillosis-related pathologies. Protein engineering and peptide synthesis have been used in order to understand the basis of these pathogenic mechanisms as well as to produce hypoallergenic proteins with potential diagnostic and immunotherapeutic applications.     

The sample processing time interval as an influential factor in flow cytometry analysis of lymphocyte subsets

The objective of this paper is to propose a protocol to analyze blood samples in yellow fever 17DD vaccinated which developed serious adverse events. We investigated whether or not the time between sample collection and sample processing could interfere in lymphocyte subset percentage, for it is often impossible to analyze blood samples immediately after collection due to transport delay from collection places to the flow cytometry facility. CD4+CD38+ T, CD8+CD38+ T, CD3+ T, CD19+ B lymphocyte subsets were analyzed by flow cytometry in nine healthy volunteers immediately after blood collection and after intervals of 24 and 48 h. The whole blood lysis method and gradient sedimentation by Histopaque were applied to isolate peripheral blood mononuclear cells for flow cytometry analyses. With the lysis method, there was no significant change in lymphocyte subset percentage between the two time intervals (24 and 48 h). In contrast, when blood samples were processed by Histopaque gradient sedimentation, time intervals for sample processing influenced the percentage in T lymphocyte subsets but not in B cells. From the results obtained, we could conclude that the whole blood lysis method is more appropriate than gradient sedimentation by Histopaque for immunophenotyping of blood samples collected after serious adverse events, due to less variation in the lymphocyte subset levels with respect to the time factor.     

Intracellular signaling mechanisms mediating catecholamine release upon activation of NPY Y1 receptors in mouse chromaffin cells

The adrenal chromaffin cells synthesize and release catecholamine (mostly epinephrine and norepinephrine) and different peptides, such as the neuropeptide Y (NPY). NPY stimulates catecholamine release through NPY Y1 receptor in mouse chromaffin cells. The aim of our study was to determine the intracellular signaling events coupled to NPY Y1 receptor activation that lead to stimulation of catecholamine release from mouse chromaffin cells. The stimulatory effect of NPY mediated by NPY Y1 receptor activation was lost in the absence of extracellular Ca2+. On the other hand, inhibition of nitric oxide synthase and guanylyl cyclase also decreased the stimulatory effect of NPY. Moreover, catecholamine release stimulated by NPY or by the nitric oxide donor (NOC-18) was inhibited by mitogen-activated protein kinase (MAPK) and protein kinase C inhibitors. In summary, in mouse chromaffin cells, NPY evokes catecholamine release by the activation the NPY Y1 receptor, in a Ca2+-dependent manner, by activating mitogen-activated protein kinase and promoting nitric oxide production, which in turn regulates protein kinase C and guanylyl cyclase activation.     

Value of cytology in papillary condylomatous lesions of the cervix

OBJECTIVE: To determine the value of cytology in detecting mature and immature papillary condylomas of the uterine cervix. STUDY DESIGN: We evaluated 240 cases of plane cervical intraepithelial neoplasia, grade 1 (CIN 1), and 23 papillary condylomas by Pap smear and biopsy and classified histologic sections according to maturity and keratinization. We reevaluated corresponding cytologic smears and identified criteria of low grade squamous lesion (LSIL) and human papillomavirus (HPV) infection. RESULTS: Thirteen (56.5%) papillary lesions were histologically classified as mature, 6 (26%) as immature and 4 (17.3%) as mixed. Fifteen lesions (65.2%) were nonkeratinized, 2 (8.6%) keratinized and 6 (26%) partially keratinized. Corresponding smears were cytologically diagnosed as LSIL (6, 26%), atypical squamous cells of undetermined significance (ASCUS) (7, 30.4%) and negative (10, 43.4%). Careful cytologic review diagnosed only two of the 13 mature lesions; few cytological criteria of LSIL and HPV infection were observed. Koilocytes were seen in just 1 case. Sample limiting factors occurred in 4 cases: 2 cytologically diagnosed as LSIL, 1 asASCUS and 1 as negative for lesion. CONCLUSION: Cytology was not effective in the detection of cervical condyloma acuminatum, independent of limitations in sample adequacy and of the degree of maturity or keratinization of the lesions.