Participation of Actin on Giardia lamblia Growth and Encystation

BACKGROUND:Microfilaments play a determinant role in different cell processes such as: motility, cell division, phagocytosis and intracellular transport; however, these structures are poorly understood in the parasite Giardia lamblia. METHODOLOGY AND PRINCIPAL FINDINGS:By confocal microscopy using TRITC-phalloidin, we found structured actin distributed in the entire trophozoite, the label stand out at the ventral disc, median body, flagella and around the nuclei. During Giardia encystation, a sequence of morphological changes concurrent to modifications on the distribution of structured actin and in the expression of actin mRNA were observed. To elucidate whether actin participates actively on growth and encystation, cells were treated with Cytochalasin D, Latrunculin A and Jasplakinolide and analyzed by confocal and scanning electron microscopy. All drugs caused a growth reduction (27 to 45%) and changes on the distribution of actin. Besides, 60 to 80% of trophozoites treated with the drugs, exhibited damage at the caudal region, alterations in the flagella and wrinkles-like on the plasma membrane. The drugs also altered the cyst-yield and the morphology, scanning electron microscopy revealed diminished cytokinesis, cysts with damages in the wall and alterations in the size and on the intermembranal space. Furthermore, the drugs caused a significant reduction of the intensity of fluorescence-labeled CWP1 on ESV and on cyst wall, this was coincident with a reduction of CWP1 gene expression (34%). CONCLUSIONS AND SIGNIFICANCE:All our results, indicated an important role of actin in the morphology, growth and encystation and indirectly suggested an actin role in gene expression

Comparison of some reproductive characteristics of farmed and wild white shrimp males Litopenaeus vannamei (Decapoda : Penaeidae)

We rated some reproductive characteristics of white shrimp Litopenaeus vannamei (Boone, 1931) males using 46 farmed individuals (weighing 21.42 +/- 0.56 g) and 40 wild individuals (weighing 36.10 +/- 0.72 g). In farmed shrimps, spermatophore mean weight was 8.94 +/- 0.51 m

Congenital toxoplasmosis: Specific IgG subclasses in mother/newborn pairs

Anti-Toxoplasma gondii antibodies of all IgG subclasses were studied in mother/newborn pairs. IgG1 in the mothers and IgG3 in the newborns were related to offspring clinical problems; IgG2 and IgG3 in the babies were markers of vertical transmission, and IgG4 in mothers or children were associated to clinical problems. IgG subclasses may be markers of congenital infection or clinical outcome. © 2008 Lippincott Williams & Wilkins

Frequency of Toxoplasma gondii in Pork Meat in Ocotlan, Jalisco, Mexico

Toxoplasmosis is an infection caused by Toxoplasma gondii, an intracellular obligate parasite. Its transmission has usually been attributed to ingestion of undercooked or raw meat. The frequency of T. gondii in pork, the most common meat for human consumption in Jalisco, Mexico, is unknown; in Guadalajara city high prevalence of human toxoplasmosis has been documented. Forty-eight samples of pork meat from butcher shops in Ocotlan city were analyzed. Through bioassay, 50 g of tissue was homogenized in an acidic pepsin solution and inoculated subcutaneously to previously immunosuppressed mice. Blood samples from the mice tail vein were obtained before inoculation and 7, 14, 28, and 45 days postinoculation to analyze anti-Toxoplasma immunoglobulin (Ig) M and IgG antibody kinetics by indirect enzyme-linked immunosorbent assay. For histopathology, small fragments of the brain, lungs, heart, and skeletal muscle were extracted on day 45 and were stained with hematoxylin and eosin. Also, DNA was extracted from the pork meat for PCR amplification of the Bl gene. Even though all pork samples were negative by histopathology and PCR, IgG and IgM antibodies against T. gondii were detected in 1 of the 48 inoculated mice, reflecting a frequency of 2.1% positive pork meat, which is lower than expected but similar to that found in other regions. Copyright © International Association for Food Protection

Rivaroxaban or aspirin for patent foramen ovale and embolic stroke of undetermined source: a prespecified subgroup analysis from the NAVIGATE ESUS trial

Background: Patent foramen ovale (PFO) is a contributor to embolic stroke of undetermined source (ESUS). Subgroup analyses from previous studies suggest that anticoagulation could reduce recurrent stroke compared with antiplatelet therapy. We hypothesised that anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, would reduce the risk of recurrent ischaemic stroke compared with aspirin among patients with PFO enrolled in the NAVIGATE ESUS trial. Methods: NAVIGATE ESUS was a double-blinded, randomised, phase 3 trial done at 459 centres in 31 countries that assessed the efficacy and safety of rivaroxaban versus aspirin for secondary stroke prevention in patients with ESUS. For this prespecified subgroup analysis, cohorts with and without PFO were defined on the basis of transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE). The primary efficacy outcome was time to recurrent ischaemic stroke between treatment groups. The primary safety outcome was major bleeding, according to the criteria of the International Society of Thrombosis and Haemostasis. The primary analyses were based on the intention-to-treat population. Additionally, we did a systematic review and random-effects meta-analysis of studies in which patients with cryptogenic stroke and PFO were randomly assigned to receive anticoagulant or antiplatelet therapy. Findings: Between Dec 23, 2014, and Sept 20, 2017, 7213 participants were enrolled and assigned to receive rivaroxaban (n=3609) or aspirin (n=3604). Patients were followed up for a mean of 11 months because of early trial termination. PFO was reported as present in 534 (7·4%) patients on the basis of either TTE or TOE. Patients with PFO assigned to receive aspirin had a recurrent ischaemic stroke rate of 4·8 events per 100 person-years compared with 2·6 events per 100 person-years in those treated with rivaroxaban. Among patients with known PFO, there was insufficient evidence to support a difference in risk of recurrent ischaemic stroke between rivaroxaban and aspirin (hazard ratio [HR] 0·54; 95% CI 0·22–1·36), and the risk was similar for those without known PFO (1·06; 0·84–1·33; pinteraction=0·18). The risks of major bleeding with rivaroxaban versus aspirin were similar in patients with PFO detected (HR 2·05; 95% CI 0·51–8·18) and in those without PFO detected (HR 2·82; 95% CI 1·69–4·70; pinteraction=0·68). The random-effects meta-analysis combined data from NAVIGATE ESUS with data from two previous trials (PICSS and CLOSE) and yielded a summary odds ratio of 0·48 (95% CI 0·24–0·96; p=0·04) for ischaemic stroke in favour of anticoagulation, without evidence of heterogeneity. Interpretation: Among patients with ESUS who have PFO, anticoagulation might reduce the risk of recurrent stroke by about half, although substantial imprecision remains. Dedicated trials of anticoagulation versus antiplatelet therapy or PFO closure, or both, are warranted. Funding: Bayer and Janssen