A new approach for the characterization of proliferative cells in cestodes

Cestodes show a remarkable proliferative capability that sustains the constant growth and differentiation of proglottids essential for their lifestyle. It is believed that a separate population of undifferentiated stem cells (the so-called germinative cells) are the only cells capable of proliferation during growth and development. The study of this particular cell subpopulation is hampered by the current lack of methods to isolate it. In this work, we developed a reproducible flow cytometry and cell sorting method to quantify and isolate the proliferating cells in the tetrathyridia larvae of the model cestode Mesocestoides corti, based on the DNA content of the cells. The isolated cells display the typical germinative cell morphology, and can be used for RNA isolation with a yield in the ng to μg range. We expect that this approach may facilitate the characterization of the germinative cells in M. corti and other model tapeworms.

Prediction of extracapsular disease with multiparametric magnetic resonance imaging in high risk localized prostate cancer patient

OBJECTIVES

To assess the usefulness of multiparametric magnetic resonance imaging (MRI) in the staging of patients with localized prostate cancer (PC) and high risk of extracapsular disease (ECD).

METHODS

Retrospective study including 30 patients with localized PC and high risk of ECD. Pathologist and radiologist established an ECD suspicion according to the evaluation of the prostatic biopsy specimens and the multiparametric MRI analysis, respectively. Radical prostatectomy (RP) specimen analysis was used as a definitive confirmatory reference. Kappa (k)test was used to assess the degree of consistency between the initial suspicion provided by both specialists and the reference RP specimen.

RESULTS

When the prostatic gland was analyzed as a single unit, the pathological evaluation of the biopsy specimens did not correctly detect the risk of ECD in 46.6% of the patients (14/30; 10 FN; k=-0.035, 95%CI [-0.29-0.36]), while multiparametric MRI did not do in 36% of the cases (11/30, 9 FP; k=0.27, 95%CI [-0.03-0.61]). Whereas, if each side of the prostate (i.e. right and left) was considered as an independent observation, the pathologist wrongly predicted the risk of ECD in 35% of the cases (21/60; 18 FN; k=0.19, 95%CI [-0.03-0.40]), while the radiologist erred only in 18.3% of the cases (11/60; 7 FN and 4 FP; k=0, 61, 95%CI [0.40-0.81]).

CONCLUSIONS

Data from our experience suggest an added value of multiparametric MRI in the clinical staging of localized PC in cases of high risk of ECD. Multiparametric MRI may be used as a helpful tool in the surgical planning and the decision-making process regarding the management of this entity.

Role of TNF in sickness behavior and allodynia during the acute phase of Chagas' disease

Chagas disease, caused by the intracellular protozoan Trypanosoma cruzi, is associated with inflammation, discomfort and pain during the acute phase. The influence of TNF-α (tumor necrosis factor) in this disease outcome is controversial. In this way, the aim of this work was to determine the role of the TNF-α blocker etanercept in the pain, discomfort, and survival during the Chagas' acute phase of mice experimentally infected with a wild virulent strain of T. cruzi. The infection with this wild strain was responsible for a severe visceral inflammation and said parasite showed a tropism in peritoneal fluid cells. Etanercept was able to restore spontaneous vertical and horizontal activities during the second week after infection and to abolish mechanical allodynia during the first week after infection. Finally, etanercept delayed the mortality without any effect on the parasitemia rates. This is the first report that correlates sickness behavior and allodynia with TNF-α and suggests that this cytokine may play an important role in the physiopathology of the acute phase.

Effect of universal MODS access on pulmonary tuberculosis treatment outcomes in new patients in Peru

SETTING

Primary health care centres in Callao, Peru.

OBJECTIVES

To evaluate the effect of universal access to the microscopic-observation drug susceptibility (MODS) assay on treatment outcomes in new and primary multidrug-resistant tuberculosis (MDR-TB) patients and on the process of drug susceptibility testing (DST).

DESIGN

Retrospective review of tuberculosis (TB) registers and clinical records before (2007) and after (2009) the introduction of MODS in 2008.

RESULTS

There were 281 patients in each cohort. Favourable treatment outcomes for 2007 (81%) and 2009 (77%) cohorts were similar. There was an increase in loss to follow-up (from 6% to 10%, P = 0.04) and a reduction in failure rates (from 4% to 0.4%, P = 0.01) in the 2009 compared with the 2007 cohort. In new MDR-TB cases (n = 22), a favourable treatment outcome was improved (from 46% to 82%, P = 0.183) in the 2009 cohort. DST coverage improved (from 24% to 74%, P < 0.001), and a significant reduction in time to diagnosis of drug-susceptible (from 118 to 33 days, P < 0.001) and MDR-TB (from 158 to 52 days, P =30.003) was observed in the 2009 cohort.

CONCLUSION

Universal access to MODS increased DST coverage, reduced the time required to obtain DST results and was associated with reduced failure rates. MODS can make an important contribution to TB management and control in Peru.

The kinetoplastid chemotherapy revisited: current drugs, recent advances and future perspectives

Leishmaniasis, African sleeping sickness and Chagas disease, caused by the kinetoplastid parasites Leishmania spp, Trypanosoma brucei and Trypanosoma cruzi, respectively, are among the most important parasitic diseases, affecting millions of people and considered to be within the most relevant group of neglected tropical diseases. The main alternative to control such parasitosis is chemotherapy. Nevertheless, the current chemotherapeutic treatments are far from being satisfactory. This review outlines the current understanding of different drugs against leishmaniasis, African sleeping sickness and Chagas disease, their mechanism of action and resistance. Recent approaches in the area of anti-leishmanial and trypanocidal therapies are also enumerated, new modulators from the mode of action, development of new formulations of old drugs, therapeutic switching and "in silico" drug design.

Reliability of the MODS assay decentralisation process in three health regions in Peru

OBJECTIVE

To deliver rapid isoniazid (INH) and rifampicin (RMP) drug susceptibility testing (DST) close to the patient, we designed a decentralisation process for the microscopic observation drug susceptibility (MODS) assay in Peru and evaluated its reliability.

METHODS

After 2 weeks of training, laboratory staff processed ≥ 120 consecutive sputum samples each in three regional laboratories. Samples were processed in parallel with MODS testing at an expert laboratory. Blinded paired results were independently analysed by the Instituto Nacional de Salud (INS) according to pre-determined criteria: concordance for culture, DST against INH and RMP and diagnosis of multidrug-resistant tuberculosis (MDR-TB) ≥ 95%, McNemar's P > 0.05, kappa index (κ) ≥ 0.75 and contamination 1-4%. Sensitivity and specificity for MDR-TB were calculated.

RESULTS

The accreditation process for Callao (126 samples, 79.4% smear-positive), Lima Sur (n = 130, 84%) and Arequipa (n = 126, 80%) took respectively 94, 97 and 173 days. Pre-determined criteria in all regional laboratories were above expected values. The sensitivity and specificity for detecting MDR-TB in regional laboratories were >95%, except for sensitivity in Lima Sur, which was 91.7%. Contamination was 1.0-2.3%. Mean delay to positive MODS results was 9.9-12.9 days.

CONCLUSION

Technology transfer of MODS was reliable, effective and fast, enabling the INS to accredit regional laboratories swiftly.

Effect of bovine lactoferrin addition to milk in yogurt manufacturing

The aim of this work was to study the effect of milk supplementation with lactoferrin of different iron saturation on the manufacturing and characteristics of yogurt. Bovine lactoferrin was added at concentrations of 0.5, 1, and 2 mg/mL in the holo (iron saturated) and apo (without iron) forms. Some physicochemical properties, such as pH, concentration of lactic acid, and texture of supplemented yogurts, were determined throughout the shelf-life period storage (28 d) at 4°C. We also evaluated the stability of lactoferrin in supplemented yogurt throughout the storage time. The supplementation of milk with bovine lactoferrin did not greatly affect the physical properties of the yogurt, though apo-lactoferrin slightly delayed the decrease of pH. This could be attributed to the partial inhibition observed on the growth of Streptococcus thermophilus. The integrity and immunoreactive concentration of lactoferrin, determined by Western blotting and noncompetitive ELISA, respectively, remained constant throughout the shelf life of yogurt.

MODS accreditation process for regional reference laboratories in Peru: validation by GenoType® MTBDRplus

SETTING

Although considerable effort has been put into the development and evaluation of new diagnostics for tuberculosis (TB) and multidrug-resistant TB (MDR-TB), little attention has thus far been paid to the technical aspects of initiating quality-assured routine service use. For implementation of the microscopic-observation drug susceptibility (MODS) methodology in the Peruvian reference laboratory network, a laboratory accreditation process was devised; MODS results from an expert reference laboratory (Universidad Peruana Cayetano Heredia [UPCH]) were used as the standard against which implementing laboratory MODS results were judged to ensure that, prior to use for patient care, implementing laboratories achieved the same high performance with MODS as previously demonstrated in the research laboratory.

OBJECTIVE

To evaluate the validity of MODS-based accreditation and the concordance of MODS drug susceptibility testing (DST) with molecular testing.

DESIGN

Head-to-head comparison of MODS DST results from implementing Peruvian regional reference laboratories and the accrediting expert MODS laboratory (UPCH) with GenoType® MTBDRplus DST.

RESULTS

The concordance of phenotypic MODS rifampicin (RMP) DST with GenoType MTBDRplus was respectively 97.4%, 97.9% and 97.1% for the two implementing regional laboratories and UPCH, and respectively 94.7%, 95.7% and 94.6% for isoniazid (INH) DST.

CONCLUSION

High and consistent levels of MODS/MTBDRplus concordance for INH and RMP DST confirm the validity of the use of rapid methods as reference standards for accreditation.