Assessment of in vivo complement activation on the Echinococcus granulosus hydatid cyst wall

The larval stage of the parasite Echinococcus granulosus causes hydatid disease. The hydatid cyst is potentially capable of activating host complement, since it is a large, persistent, carbohydrate-rich structure, coated with host immunoglobulins, and localized in the host's internal organs. Nonetheless, in vitro studies have suggested that the cyst surface, the hydatid cyst wall (HCW), is a poor complement activator. In this study, we assessed the occurrence of in vivo complement activation on the hydatid cyst by measuring the levels of two complement activation products, C3d and complexes bearing a C9 activation neoepitope (TCC/MAC), in extracts from HCW of human origin. Low amounts of C3d and TCC/MAC were found in HCW in comparison with their levels in normal human plasma and activated human sera, suggesting that in vivo complement activation on HCW is efficiently down-regulated. This regulation may contribute to limit host inflammation which has been observed to correlate with parasite degeneration and death.     

Diagnostic value of the copper/zinc ratio in hepatocellular carcinoma: a case control study

Background: The aim of this study was to assess the accuracy of the copper/zinc ratio in the evaluation of a group of patients with hepatocellular carcinoma (HCC). Methods: A total of 105 patients were studied and separated into three groups: group I (n = 40), patients with HCC, group II (n = 25), patients with liver cirrhosis, and group III (n = 40), patients with benign digestive disease. Serum levels of copper and zinc were measured by atomic absorption spectrophotometry. Results: The serum levels of copper (μg/dl) in patients with HCC (97.4 ± 27.2; P < 0.05) were significantly higher than those in patients with liver cirrhosis (73.7 ± 17.5) or benign digestive disease (77.1 ± 20.8), and the serum levels of zinc (μg/dl) were significantly lower (71.6 ± 30.5; P < 0.05) than those in patients with benign digestive disease (81.7 ± 17.7 μg/dl) and were similar to those in cirrhotic patients (68.5 ± 17.1). The Cu/Zn ratio was also significantly higher in patients with HCC (1.52 ± 0.64; P < 0.05) than in patients with liver cirrhosis (1.06 ± 0.2) or patients with benign digestive disease (0.95 ± 0.39). Considering a cutoff value of 1.15, the sensitivity of the Cu/Zn ratio was 87.5%, with a specificity of 86.1%, a positive predictive value of 79.5%, and a negative predictive value of 91.8%. Conclusions: The Cu/Zn ratio was found to be significantly higher in patients with HCC compared with that in age and sex-matched controls, with a sensitivity of 87.5%; this ratio might be useful in the evaluation of suspected hepatocellular malignancy. Received: February 15, 2002 / Accepted: June 14, 2002 Acknowledgments. This work was partially supported by grant No. D-113-903903 from the Consejo Nacional de Ciencia y Tecnología, Mexico City, México. Reprint requests to: J.L. Poo, Centro de Investigación Farmacológica y Biotecnológica, Hospital Médica Sur, Puente de Piedra No 150, 14050, Mexico City, Mexico Editorial on page 104     

Hodgkin and Reed-Sternberg cells harbor alterations in the major tumor suppressor pathways and cell-cycle checkpoints: analyses using tissue microarrays

Tumoral cells in Hodgkin lymphoma (HL) display an increased growth fraction and diminished apoptosis, implying a profound disturbance of the cell cycle and apoptosis regulation. However, limitations of molecular techniques have prevented the analysis of the tumor suppressor pathways and cell-cycle checkpoints. Tissue microarray (TMA) is a powerful tool for analyzing a large number of molecular variables in a large series of tumors, although the feasibility of this technique has not yet been demonstrated in heterogeneous tumors. The expression of 29 genes regulating the cell cycle and apoptosis were analyzed by immunohistochemistry and in situ hybridization in 288 HL biopsies using TMA. The sensitivity of the technique was validated by comparing the results with those obtained in standard tissue sections. The results revealed multiple alterations in different pathways and checkpoints, including G1/S and G2/M transition and apoptosis. Striking findings were the overexpression of cyclin E, CDK2, CDK6, STAT3, Hdm2, Bcl2, Bcl-X(L), survivin, and NF-kappaB proteins. A multiparametric analysis identified proteins associated with increased growth fraction (Hdm2, p53, p21, Rb, cyclins A, B1, D3, and E, CDK2, CDK6, SKP2, Bcl-X(L), survivin, STAT1, and STAT3), and proteins associated with apoptosis (NF-kappaB, STAT1, and RB). The analysis also demonstrated that Epstein-Barr virus (EBV)-positive cases displayed a characteristic profile, confirming the pathogenic role of EBV in HL. Survival probability depends on multiple biologic factors, including overexpression of Bcl2, p53, Bax, Bcl-X(L), MIB1, and apoptotic index. In conclusion, Hodgkin and Reed-Sternberg cells harbor concurrent and overlapping alterations in the major tumor suppressor pathways and cell-cycle checkpoints. This appears to determine the viability of the tumoral cells and the clinical outcome.     

Elevated nitric oxide and 3′,5′ cyclic guanosine monophosphate levels in patients with alcoholic cirrhosis

AIM： To evaluate whether serum levels of nitric oxide （NO^.） and plasma levels of cyclic guanosine monophosphate （cGMP） and total glutathione （GSH） are altered in patients with alcoholic cirrhosis and to examine their correlation with the severity of liver disease.
METHODS： Twenty-six patients with alcoholic liver cirrhosis were studied. Serum levels of NO^. and plasma levels of cGMP and GSH were measured in 7 patients with compensated alcoholic cirrhosis （Child-Pugh A） and 19 patients with advanced cirrhosis （Child-Pugh B and C）. The model for end-stage liver disease （MELD） score was evaluated. Sixteen healthy volunteers served as controls. Liver enzymes and creatinine levels were also tested.
RESULTS： NO^. and cGMP levels were higher in patients with Child-Pugh B and C cirrhosis than in Child-Pugh A cirrhosis or controls （NO^.： 21.70 ± 8.07 vs 11.70 ± 2.74; 21.70± 8.07 vs 7.26 ± 2.47 μmol/L, respectively; P 〈 0.001） and （cGMP： 20.12 ± 6.62 vs 10.14 ± 2.78; 20.12 ± 6.62 vs 4.95 ± 1.21 pmol/L, respectively; P 〈 0.001）. Total glutathione levels were lower in patients with Child-Pugh B and C cirrhosis than in patients with Child-Pugh A cirrhosis or controls （16.04 ± 6.06 vs 23.01 ± 4.38 or 16.04 ± 6.06 vs 66.57 ±26.23 μmol/L, respectively; P 〈 0.001）. There was a significant correlation between NO^. and cGMP levels in all patients with alcoholic cirrhosis. A significant negative correlation between reduced glutathione/glutathione disulfide and the MELD score was found in all cirrhotic patients.
CONCLUSION： Our results suggest a role for oxidative stress in alcoholic liver cirrhosis, which is more significant in decompensated patients with higher levels of NO^. and cGMP and lower GSH levels than in compensated and control patients. Altered mediator levels in decompensated patients may influence the hemodynamic changes in and progression of liver disease.     

sparse inflorescence1 encodes a monocot-specific YUCCA-like gene required for vegetative and reproductive development in maize

The plant growth hormone auxin plays a critical role in the initiation of lateral organs and meristems. Here, we identify and characterize a mutant, sparse inflorescence1 (spi1), which has defects in the initiation of axillary meristems and lateral organs during vegetative and inflorescence development in maize. Positional cloning shows that spi1 encodes a flavin monooxygenase similar to the YUCCA (YUC) genes of Arabidopsis, which are involved in local auxin biosynthesis in various plant tissues. In Arabidopsis, loss of function of single members of the YUC family has no obvious effect, but in maize the mutation of a single yuc locus causes severe developmental defects. Phylogenetic analysis of the different members of the YUC family in moss, monocot, and eudicot species shows that there have been independent expansions of the family in monocots and eudicots. spi1 belongs to a monocot-specific clade, within which the role of individual YUC genes has diversified. These observations, together with expression and functional data, suggest that spi1 has evolved a dominant role in auxin biosynthesis that is essential for normal maize inflorescence development. Analysis of the interaction between spi1 and genes regulating auxin transport indicate that auxin transport and biosynthesis function synergistically to regulate the formation of axillary meristems and lateral organs in maize.     

Marcadores de daño miocárdico en la predicción del pronóstico a corto plazo de los pacientes con COVID-19

Introduction and objectivesCOVID-19 is currently causing high mortality and morbidity worldwide. Information on cardiac injury is scarce. We aimed to evaluate cardiovascular damage in patients with COVID-19 and determine the correlation of high-sensitivity cardiac-specific troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) with the severity of COVID-19.MethodsWe included 872 consecutive patients with confirmed COVID-19 from February to April 2020. We tested 651 patients for high-sensitivity troponin T (hs-TnT) and 506 for NT-proBNP on admission. Cardiac injury was defined as hs-TnT > 14 ng/L, the upper 99th percentile. Levels of NT-proBNP > 300 pg/mL were considered related to some extent of cardiac injury. The primary composite endpoint was 30-day mortality or mechanical ventilation (MV).ResultsCardiac injury by hs-TnT was observed in 34.6% of our COVID-19 patients. Mortality or MV were higher in cardiac injury than noncardiac injury patients (39.1% vs 9.1%). Hs-TnT and NT-proBNP levels were independent predictors of death or MV (HR, 2.18; 95%CI, 1.23-3.83 and 1.87 (95%CI, 1.05-3.36), respectively) and of mortality alone (HR, 2.91; 95%CI, 1.211-7.04 and 5.47; 95%CI, 2.10-14.26, respectively). NT-ProBNP significantly improved the troponin model discrimination of mortality or MV (C-index 0.83 to 0.84), and of mortality alone (C-index 0.85 to 0.87).ConclusionsMyocardial injury measured at admission was a common finding in patients with COVID-19. It reliably predicted the occurrence of mortality and need of MV, the most severe complications of the disease. NT-proBNP improved the prognostic accuracy of hs-TnT.     

A post hoc analysis of dalteparin versus oral anticoagulant (VKA) therapy for the prevention of recurrent venous thromboembolism (rVTE) in patients with cancer and renal impairment

Venous thromboembolism (VTE) is a common and serious complication in patients with cancer; treatment guidelines recommend extended therapy of ≥6 months with low-molecular-weight heparin (LMWH) for treatment and prevention of recurrent VTE (rVTE) in this population. This post hoc analysis used data from the CLOT study—a phase III, randomized, open-label, controlled study (N = 676)—to compare the efficacy and safety of dalteparin, a LMWH, versus vitamin K antagonist (VKA) for prevention of rVTE in patients with cancer and renal impairment (creatinine clearance <60 ml/min). Overall, 162/676 (24 %) patients had renal impairment at baseline. Patients received subcutaneous dalteparin 200 IU/kg once daily during month 1, followed by 150 IU/kg once daily for months 2–6; or VKA once daily for 6 months, with initial overlapping subcutaneous dalteparin 200 IU/kg once daily for ≥5 days until international normalized ratio was 2.0–3.0 for 2 consecutive days. Endpoints included the rates of rVTE (primary) and bleeding events. Overall, fewer dalteparin-treated patients (2/74 [2.7 %]) experienced ≥1 adjudicated symptomatic rVTE compared with VKA-treated patients (15/88 [17.0 %]; hazard ratio = 0.15 [95 % confidence interval 0.03–0.65]; p = 0.01). Bleeding event rates for both treatments were similar (p = 0.47). In summary, compared with VKA, dalteparin significantly reduced risk of rVTE in patients with cancer and renal impairment (p = 0.01) while exhibiting a comparable safety profile. This analysis supports dosing patients with renal impairment in accordance with patients with normal renal function; however, anti-Xa monitoring could be considered to further support safety in selected patients, particularly those with very severe renal impairment.     

Compression forces generated by actin comet tails on lipid vesicles

Polymerizing networks of actin filaments generate force for a variety of movements in living cells, including protrusion of filopodia and lamellipodia, intra- and intercellular motility of certain bacterial and viral pathogens, and motility of endocytic vesicles and other membrane-bound organelles. During actin-based motility, coexisting populations of actin filaments exert both pushing and retarding forces on the moving cargo. To examine the distribution and magnitude of forces generated by actin, we have developed a model system where large artificial lipid vesicles coated with the protein ActA from the bacterial pathogen Listeria monocytogenes are propelled by actin polymerization in cytoplasmic extract. We find that motile vesicles associated with actin comet tails are significantly deformed due to an inward compression force exerted by actin polymerization orthogonal to the direction of motion, which is >10-fold greater in magnitude than the component of the force exerted in the direction of motion. Furthermore, there is a spatial segregation of the pushing and retarding forces, such that pushing predominates along the sides of the vesicle, although retarding forces predominate at the rear. We estimate that the total net (pushing minus retarding) force generated by the actin comet tail is approximately 0.4-4 nN. In addition, actin comet tail formation is associated with polarization of the ActA protein on the fluid vesicle surface, which may reinforce the persistence of unidirectional motion by helping to maintain a persistent asymmetry of actin filament density.     

Biological characterization of Trypanosoma cruzi stocks from domestic and sylvatic vectors in Sierra Nevada of Santa Marta, Colombia

Sierra Nevada of Santa Marta is one of the most endemic regions of Chagas disease in Colombia. In this study, we compared the biological behavior and genetic features of Trypanosoma cruzi stocks that were isolated from domestic and sylvatic insects in this area. Rhodnius prolixus (from domestic environments) and Triatoma dimidiata (from sylvatic, peridomestic and domestic environments) are the most important vectors in this region. Genetic characterization showed that all stocks corresponded to T. cruzi I, but LSSP-PCR analyses indicated that some genotypes were present in both environments. Biological characterization in vitro showed a low growth rate in sylvatic T. cruzi stocks and in some domestic T. cruzi stocks, possibly indicating the presence of stocks with similar behavior in both transmission cycles. In parallel, in vivo behavioral analysis also indicated that T. cruzi stocks are variable and this species did not show a correlation between the environments where they were isolated. In addition, all stocks demonstrated a low mortality rate and histopathological lesions in heart, skeletal muscle and colon tissue. Moreover, our data indicated that experimentally infected chagasic mice displayed a relation between their myocardial inflammation intensity, parasitism tissue and parasite load using the qPCR.In conclusion, our results indicate that the T. cruzi stocks present in SNSM have similar biological behavior and do not show a correlation with the different transmission cycles. This could be explained by the complex transmission dynamics of T. cruzi in Sierra Nevada of Santa Marta, where hosts, vectors (e.g., T. dimidiata) and reservoirs circulate in both environments due to the close contact between the two transmission cycles, favoring environment overlapping. This knowledge is an important key to understanding the epidemiology and pathology of Chagas disease in this Colombian region. Furthermore, our findings could be of significant use in the design of control strategies restricted to a specified endemic region.