A Rapporteur\u27s Summary : Vector Control

Vector control is essential for control of the occurrence of dengue virus infections. Through discussions by participants of the session IV, it became apparent that shortage of professionals in the field of entomology and lack of simple messages that motivate community participation may be a key for overcoming difficulties in vector control. Thus, the establishment of an international or regional training course for young scientists must be proposed under the sponsorship of either international organizations or semi-governmental agencies

Resolution and Resurgence of Schistosoma haematobium—induced Pathology After Community-based Chemotherapy in Ghana, as Detected by Ultrasound

Community-based treatment is recommended for endemic populations with urinary schistosomiasis; however, the optimal target group for treatment and retreatment interval have not been established. Using ultrasound, this study identified subpopulations whose lesions were most likely to respond to treatment and characterized resurgence of pathology. Ultrasound examination of 1202 infected patients was followed by chemotherapy with praziquantel. A sample of 698 patients was followed for 18 months after treatment. Nearly all types of bladder pathologies resolved after treatment, regardless of patient's age or intensity of initial infection. However, many patients' upper urinary tract pathologies (62.5%) did not resolve. During the 18-month follow-up period, reappearance of severe bladder pathologies was rare, and < 10% of persons had resurgence of mild bladder pathologies. For this population, re-treatment is not needed annually but might be cost effective if given several years later. Confirmation from other areas is required before general policies can be forme

Role of a mouse monoclonal IgE antibody in passive transfer of immunity to Schistosoma japonicum infection

We have been able to produce a mouse monoclonal IgE antibody specific to an adult worm antigen extracted from Schistosoma japonicum (Sj). The antibody was able to elicit passive cutaneous anaphylaxis in the rat skin against Sj with the highest titer of 1:256,000 but did not cross-react with S. mansoni antigen. The antibody recognized a 97-kDa molecule expressed on the surface of mechanically transformed schistosoma of S. japonicum. Passive transfer of the antibody into mice in the early stage of challenge infection resulted in a partial but significant reduction of recovery of adult worms. Induction of eosinophilia by an oral administration of embryonated eggs of Toxocara canis prior to challenge infection enhanced the reduction

Correlation between kinetics and chemical bonding state of catalyst surface in catalyzed magnesium hydride

We reported on the hydrogen desorption properties, microstructure, kinetics, and chemical bonding state of catalyst surface for composites of MgH2 and 1 mol% Nb2O5 ball-milled for 0.02 h, 0.2 h, 2 h, 20 h under 1 MPa H2 atmosphere, as well as hand-mixed (HM) one. Hydrogen desorption properties were significantly improved by ball-milling with Nb2O5. Then, we estimated by Kissinger Method the activation energy (Ea) of hydrogen desorption reaction that decreased with the increase of ball-milling time. Especially, Ea of the sample ball-milled for 0.2 h was drastically decreased, compared with that of the sample ball-milled for 0.02 h. TEM observations revealed that the distribution of Nb2O5 in MgH2 was gradually improved during ball-milling. On the other hand, we confirmed by XPS that in the sample ball-milled for 0.2 h, Nb_[2]O_[5-x] phase(s) existed at least on the surface. It can be suggested that these deoxidized Nb_[2]O_[5-x] phases eventually decrease Ea as substantial catalyst rather than Nb2O5 itself

Comparative study and cDNA cloning of the flavoprotein subunit of mitochondrial complex II (succinate-ubiquinone oxidoreductase: fumarate reductase) from the dog heartworm, dirofilaria immitis

Mitochondrial complex II functions as a fumarate reductase (FRD), the reverse reaction of succinate dehydrogenase (SDH), and plays an important role in the anaerobic respiratory chain of parasitic helminths. In this study, complex II from the dog heartworm, Dirofilaria immitis adult, which is thought to act as a homolactatic fermenter, was examined in terms of its enzymatic features and primary structure in order to investigate the possible role of mitochondria in this filaria. Mitochondria from D. immitis adult showed high FRD activity when the enzymatic assay was performed using methylviologen as an artificial electron donor. The ratio of SDH to FRD in D. immitis was comparable to that in Ascaris suum adult, which is known to have an anaerobic mitochondrial respiratory chain with a high FRD activity of complex II. The FRD activity of D. immitis mitochondria was inhibited by the sulfhydryl reagent N-ethylmaleimide (NEM), while that of A. suum complex II was resistant to this inhibitor. The presence of the flavoprotein (Fp) subunit, which contains the substrate binding active site, was confirmed in D. immitis mitochondria by immunoblotting using a monoclonal antibody against the A. suum Fp subunit. By homology probing with the polymerase chain reaction, the entire cDNA for the D. immitis adult Fp was cloned and sequenced. The deduced amino acid sequence showed significant homology to that of A. suum and other mitochondrial Fps, in contrast to much less similarity to bacterial FRD, even though the D. immitis complex II showed high FRD activity. These results are the first indication of the presence of a functional complex II in D. immitis mitochondria