Point/counterpoint. ED managers: do not stop restocking.
Explore the source record for details and available documents.
Ambulances↗
Biomedical subjects
R Suter
Publications and source records attributed to R Suter.
Protective immunogenicity of Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine in children who failed to respond to prior invasive H. influenzae type b disease.
UNLABELLED: A polyribosylribitol phosphate (polysaccharide)-tetanus protein conjugate vaccine (PRP-T) against Haemophilus influenzae type b (Hib) was evaluated for protective immunogenicity in 25 previously PRP-unimmunized children who had failed to develop protective PRP antibody levels (< 1 microg/ml) after prior invasive Hib disease at median age 10 months. Children under 21 months of age at time of PRP-T immunization received one, two or three doses. Serum was obtained for total PRP antibody, complement mediated bactericidal activity and specific IgG1 and IgG2 PRP antibodies before (n = 25), 1 to 2 months (n = 24) and > 5 months (n = 13) after completed vaccination. One to 2 months after immunization, all but one patient developed > 1 microg/ml of antibody (geometric mean level 50.7 microg/ ml). The non-responder developed protective antibody levels when tested at 6 months after vaccination. Twenty out of 22 sera had detectable complement mediated bactericidal activity (median dilution titer 1:24), 1-2 months after vaccination. Three patients failed to demonstrate PRP antibodies in the IgG1 or IgG2 subclasses, although two of them had protective (> 1 microg/ml) total antibody levels. The second post immunization sera showed persistence of the total PRP antibody levels (geometric mean level 38.2 microg/ml) as well as of the bactericidal activity (median dilution titer 1:32). CONCLUSION: PRP-T conjugate vaccine is able to elicit a protective immune response in children who have low or unmeasurable PRP antibody levels after a systemic Hib infection.
Antibodies, Bacterial↗
Locomotion on the water surface: propulsive mechanisms of the fisher spider
Using kinematic and mechanical experiments, we have shown how fisher spiders, Dolomedes triton (Araneae, Pisauridae), can generate horizontal propulsive forces using their legs. This horizontal thrust is provided primarily by the drag of the leg and its associated dimple as both move across the water surface. Less important sources of resistance are surface tension and bow waves. The relative contributions of drag, surface tension and bow waves were examined in several different ways. In one experiment, we measured the forces acting on a leg segment as water flowed past it in non-turbulent flow; the bow wave was not present at leg relative velocities below 0.2ms-1 and thus cannot play a role in thrust production at low leg speeds. In a second experiment, we varied the surface tension by altering the concentration of ethanol from 0% to 9% in the experimental water tank. At a constant dimple depth, force varied little with changes in surface tension, a result consistent with the hypothesis that drag is the primary source of resistance. In addition, however, as surface tension decreased from 0.072 to 0.064Nm-1, the power exponent of the relationship between force and velocity (as measured by the exponent of the power function relating the two variables) increased; at lower surface tensions, down to 0.054Nm-1, the power exponent of the relationship between force and velocity decreased. These results suggest an influence of surface tension (albeit still secondary to drag) in generating horizontal resistance to leg movement. We also measured flow disturbance in the water downstream from a leg segment and confirmed that, even at velocities well below 0.2ms-1, the leg-cum-dimple transferred momentum to the water, which is a clear indication that drag is a contributor to the resistance encountered by a spider's leg. Finally, modeling the leg-cum-dimple as a circular cylinder generates values of drag that account for 75­98% of the measured leg force when the dimple is 0 or 1mm deep. These results not only elucidate the primary mechanism of propulsion for D. triton and other similar-sized arthropods, such as adult water striders (Gerridae), but also suggest that the formerly enigmatic locomotion of very small water-walking organisms (e.g. first-instar water striders) can be understood in the same way.
Journal Article↗
Song learning in birds: the relation between perception and production.
The vocal control system of oscine songbirds has some perplexing properties--e.g. laterality, adult neurogenesis, neuronal replacement--that are not predicted by common views of how vocal learning takes place. Similarly, we do not understand the relation between the direct pathway for the control of learned song and the recursive pathway necessary for song learning. Some of the paradoxes of the vocal system of birds may disappear once the relation between the perception and production of learned vocalizations is better understood. To some extent, perception and production may be two closely related states of a same system.
Animals↗
Longitudinal study on the health status of children in a rural Tanzanian community: parasitoses and nutrition following control measures against intestinal parasites.
Three repeated cross-sectional surveys were undertaken among children (1 month to 15 years) of a rural community in southeastern Tanzania. The study was part of a longitudinal project on the interactions among nutrition, parasitic infections and immunity within a primary health care programme emphasizing village health workers. All children underwent interviews and parasitological, anthropometric, anamnestic and clinical examinations. Out of 550-590 children examined each year, a cohort of 170 children could be followed for three consecutive years. Malaria was holo- to hyperendemic in the community, P. falciparum accounting for greater than 90% of the infections. The parasite and spleen rates were 88% and 67%, respectively, and the average enlarged spleen index was 2.0 among children from 2-9 years in 1982. Transmission of malaria was high and stable as indicated by a parasite rate of 80% among infants between 1 month and 1 year during the whole period of study. G. lamblia, hookworm (N. americanus), Strongyloides spp. and Schistosoma haematobium were highly prevalent and annual incidence rates were high, while Entamoeba histolytica, Ascaris and Trichuris were of minor importance. Prevalence and incidence of parasitic infections did not differ by sex. Multiparasitism was very frequent and less than 11% of all children were parasite-free in each year. Not a single child remained parasite-free for three consecutive years. An anthropometric assessment showed a high degree of stunting (35-71%) and a substantial proportion of wasting (3-20%). The growth potential was normal in girls and boys during the whole period of study. There were indications that malaria was the main contributory factor to growth retardation among young children. Hookworm infection did not significantly affect the packed-cell volume of the children, probably owing to the low intensity of infection. Due to the multiparasitism and the lack of parasite-free individuals, single-parasite and single-nutrient effects were difficult to unravel. A latrine campaign followed by a single mass treatment against hookworm (single oral dose of albendazole, 400 mg) and/or G. lamblia (single oral dose of ornidazole, 40 mg/kg) only temporarily affected the prevalence and incidence of G. lamblia, and only resulted in a decrease in the intensity of hookworm infections up to six months after the interventions. As the effects of the latrine campaign and a single mass treatment on the parasite load were only transient, no sustained impact on nutritional variables was observed.(ABSTRACT TRUNCATED AT 400 WORDS)
Adolescent↗
Laboratory and field trials at Ifakara (Kilombero District, Tanzania) on the plant molluscicide Swartzia madagascariensis.
The molluscicidal activity of crushed seed pods of Swartzia madagascariensis was assessed by laboratory and field trials. Mature dry seed pods were ground and extracted in tap water for 24 h. Water extracts exerted a significant molluscicidal activity against Bulinus globosus up to dilutions of 100 mg of ground pods per litre. The chromatographically isolated saponin (1) responsible for the molluscicidal activity showed a toxicity of LC 100 at 3 mg/l after exposure of B. globosus and Biomphalaria glabrata for 24 h. Saponin (1) could be identified by FAB-MS and 13C-NMR-spectroscopy as oleanolic acid-3-O-beta-D-glucuronopyranosyl (1----3)-alpha-L-rhamnopyranoside. Two field trials with S. madagascariensis pod extracts in ponds (60 and 160 m3) harbouring dense populations of B. globosus compared well with the laboratory findings and showed the efficiency of the molluscicide in a natural habitat. A single application of the plant molluscicide significantly reduced the populations of B. globusus. The toxicity of S. madagascariensis pod extracts to non-target organisms remains an obstacle for its use in certain situations where schistosomiasis control is envisaged and where S. madagascariensis is found. However, S. madagascariensis is a valid candidate molluscicide which may be applied in selected epidemiological settings as part of integrated schistosomiasis control measures.
Animals↗
CIPAC collaborative study of the heat-stability of Diazinon formulations, using both CIPAC and AOAC analytical methods.
Explore the source record for details and available documents.
Chromatography, Gas↗
Regeneration in the VIII nerve.
After transection of the VIII nerve in the inner meatus, 95% of the cochlear neurons and practically all efferent fibres degenerate and disappear. In long-term survivals, different phenomena indicate the regeneration properties of many, probably efferent or vestibular nerve fibres. The few remaining afferent neurons react to the lesion of their central axon with enormous proliferations of their peripheral branches in the organ of Corti.
Animals↗