Comparison of the enzyme linked immunosorbent assay, the haemagglutination inhibition test and the agar gel precipitation test for the detection of antibodies against infectious bronchitis and Newcastle disease in commercial broilers

Serological results as obtained by the agar gel precipitation (AGP) test, haemagglutination inhibition (HI) test (M41, D274, D1466) and an enzyme linked immunosorbent assay (ELISA) from commercial broiler flocks, which had suffered from a clinical infectious bronchitis (IB) infection in the fattening period, were compared with serological findings of control broiler flocks. In addition the Hi-test and ELISA for Newcastle disease (ND) were compared. The AGP results differ significantly between groups. The test had a low sensitivity. The results of the HI-IBV tests were similar for both groups and no difference was seen between flocks with or without clinical IB problems. The IBV ELISA showed a highly significant difference between the two groups. In contrast to the low and not significant correlation coefficients (r) between the IBV HI tests and the ELISA, the value of r between the NDV HI and ELISA was high. The results indicate an ELISA as the preferred test for the diagnosis of IB in broilers.     

K88 fimbriae as carriers of heterologous antigenic determinants.

The K88 fimbriae of enterotoxigenic Escherichia coli are strongly immunogenic antigens that can be used to evoke protective immunity. To find out whether these fimbriae can be used as carriers for foreign epitopes, a highly variable region present in the primary structure of the different K88 variants was replaced with five different heterologous epitopes to investigate to what extent these insertions affected the expression, assembly (biogenesis), stability and immunogenic properties of the resulting hybrid fimbriae. Amino acid residues 163-173, were replaced using site-directed in vitro mutagenesis and the hybrid fimbriae were tested for these aspects using ELISA, immunoelectronmicroscopy and immunoblotting. Replacement of this highly variable region did not affect the biosynthesis of fimbriae, although all mutations tested resulted in a reduced expression depending on the epitope inserted. Testing of the different hybrid fimbriae with a panel of monoclonal antibodies raised against the various K88 serotypes K88ab, K88ac and K88ad indicated that replacement of amino acid sequence 163-173 did not affect conserved or K88ab specific epitopes but the K88ac and K88ad specific conformation was lost. Immunization with hybrid fimbriae raises antibodies specific for the inserted heterologous epitopes.     

Early brain lesions and face-processing development

Studies of functional plasticity after pre- or perinatal brain damage can tell us whether the neural substrate normally involved in the development of a given ability is specific and, if so, when it becomes functionally specified and unique. Development of face processing was investigated in 5- to 17-year-old children who had a unilateral brain injury in the pre-, peri-, or postnatal period. In Studies 1 and 2, patients with a posterior injury involving the temporal regions exhibited a face-processing deficit that was independent of their age at test time. Even though differences were observed between the two hemispheres in face processing during infancy as well as in adults in cases of normal development, no clear differences between right and left injury were observed here in face-processing deficit. Poor postlesional face-processing plasticity seems to contrast with results of several studies on speech development after early unilateral injury. If the difference in the time window for postlesional plasticity between these two areas of competency is confirmed, it would suggest that the two kinds of abilities rely on neural cells which are sensitive to different plasticity factors.     

Premières observations sur deux Microsporidies hyperparasites d'Acanthocéphales de Poissons marins et lagunaires

Résumé Microsporidium acanthocephali n. sp. et Microsporidium propinqui n. sp. sont deux espèces de Microsporidies hyperparasites du syncytium tégumentaire d'Acanthocéphales de Poissons marins et lagunaires. Leur étude ultrastructurale met en évidence des caractères communs: mérontes et spores à diplocaryons, filament polaire anisofilaire, mais aussi une vacuole parasitaire autour des mérontes et quelques stades sporogoniques de l'espèce Microsporidium acanthocephali. Les spores des deux parasites sont oviformes; celles de M. acanthocephali, géantes, mesurent 12–14 m de longueur sur 6–7 m de largeur, celles de M. propinqui seulement 3–4 m X 1,25–1,50 m. La méconnaissance de certains aspects de la sporogonie empÊche une assignation générique de ces deux parasites qui peuvent cohabiter chez un mÊme Acanthocéphale.Au cours de recherches sur les Acanthocéphales de Poissons marins et lagunaires (Buron 1986), deux Microsporidies hyperparasites de ces Helminthes ont été observées chez des Poissons Gobiidae et Pleuronectiformes. Les Microsporidies sont déjà connues pour Être des hyperparasites de Grégarines, de Myxosporidies et d'autres Helminthes (Cestodes, Trématodes, Nématodes) (Sprague 1977). Il semble cependant, chez les Acanthocéphales, n'avoir été recensé jusqu'à présent que des «psorospermies» par Moniez (1879) que Balbiani (1884) interprète comme étant des Grégarines (in Dollfus 1946).Le présent travail propose donc de décrire quelques stades du cycle biologique des deux premières Microsporidies indiscutables d'Acanthocéphales.

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Preliminary observations on two microsporidian hyperparasitic in Acanthocephalan of salt water fishes

Microsporidium acanthocephali n. sp. and Microsporidium propinqui n. sp. are two microsporidian species hyperparasitic in the tegumentary syncytium of salt-water fishes. Their ultrastructural study shows that both species have diplocaryotic meronts and spores, anisofilar polar filaments; meronts and some sporogonic stages of M. acanthocephali are surrounded by a parasitic vacuole. Spores of both parasites are oviform; those of M. acanthocephali are gigantic, 12–14 m long and 6–7 m broad, those of M. propinqui are only 3–4 m X 1.25–1.50 m. A poor knowledge of some sporogonic aspects prevents us from all precise generic assigning of these two parasites which may coexist in the same Helminth.

     

High prevalence of tuberculosis in AIDS patients in Spain

A total of 67 cases of tuberculosis was diagnosed in the first 100 cases of AIDS, diagnosed according to the former CDC criteria, at a hospital in Madrid, Spain. This is the highest known prevalence of tuberculosis in AIDS patients both within and outside Spain. The clinical manifestations of tuberculosis were very variable and atypical. The rate of isolation ofMycobacterium tuberculosis from blood was particularly high: of 25 patients in whom blood cultures were performed, 16 were positive. In a third of the patients with proven mycobacteremia, blood was the first or the only positive specimen. In general, therapy resulted in rapid clinical improvement, but in some cases mycobacteria were isolated from clinical or necroscopy specimens months after what was considered adequate therapy.     

Heterogeneity of the polyribocytidilic acid tract in aphthovirus: changes in the size of the poly(C) of viruses recovered from persistently infected cattle

A sample of aphthovirus type C3 strain Resende carrying two polyribocytidilic acid [poly(C)] tracts was cloned in tissue culture. One clone with a poly(C)-rich tract of about 145 nucleotides long (clone 3B) and another with a poly(C)-rich tract of about 230 nucleotides long (clone 12) and a mixture of both were injected intralingually into three steers. Samples from all three animals were recovered during the acute phase of the disease, from the blood and from the feet, and at various days after inoculation from the oesophageal-pharyngeal (OP) fluids. Analysis of the viral RNAs of the positive samples by means of RNase T1 maps on one- and two-dimensional gels showed (1) changes in the electrophoretic mobility of the poly(C)-rich tracts of viruses recovered from the OP fluids at various times after infection; (2) selection of virus populations with poly(C)-rich tracts of increased size; (3) later on, changes in the patterns of oligonucleotides of persistent viruses. These variations may lead to the production of new strains with altered biological properties that may contribute to the maintenance and spread of these viruses in the field.     

Plasma sprayed coatings of hydroxylapatite

The technique of plasma spraying has been applied to deposit a thin, dense layer of hydroxylapatite onto a titanium substrate. Bond strength of such apatite coatings with the substrate have been measured, as well as the (absence of) influence of the coating process on fatigue properties of the substrate. Animal studies showed similar histological reactions to apatite coatings as to (well documented) apatite bulk materials.     

Ectopic granule cell layer in mouse cerebellum after methyl-azoxy-methanol (MAM) treatment

Summary Previous results from our laboratory (Bejar et al. 1985) indicated that a single injection in mouse pups of the antimitotic/mutagenic agent methylazoxymethanol at postnatal day 5 typically produces hypogranular cerebella with no changes in foliation, in contrast to the severe alterations observed after the more usual injection on the day of birth. Here we report that injection of a higher dose (30 mg/kg) of methylazoxymethanol, always at postnatal day 5, leads to the additional presence of a ectopic cell layer in adult cerebellum. Immunostaining with several antibodies recognizing cell specific proteins ruled out the possibility that these ectopic cells were glial and electron microscopy indicated that they were morphologically mature granule cells. In the molecular layer of other cerebellar areas and apparently unrelated with granule cell ectopia, ectopic Golgi epithelial cells were observed. The reason for the presence of these ectopic cells of different type in the molecular layer was discussed in relation with analogous ectopias obtained by other means.     

Excitatory amino acids mediate responses elicited in vitro by stimulation of cortical afferents to reticularis thalami neurons of the rat

The effects of the excitatory amino acids on the nucleus reticularis thalami were examined by intracellular recordings from rat thalamic slices. Non-N-methyl-D-aspartate receptor agonists and glutamate induced a membrane depolarization and a reduction in input resistance, while N-methyl-D-aspartate and aspartate induced a prolonged discharge, which in some neurons took the form of a burst firing associated with an apparent increase in membrane input resistance. Both the N-methyl-D-aspartate and the aspartate effects were blocked by D-2-amino-5-phosphonovalerate, while the effects of glutamate, kainate and quisqualate were not. The excitatory postsynaptic potential evoked by corticothalamic fiber stimulation shows two components: an early, short-lasting, 2-amino-5-phosphonovalerate-insensitive portion, and a late, 2-amino-5-phosphonovalerate-sensitive decay phase. It is suggested that glutamate acts in nucleus reticularis thalami cells preferentially on the non-N-methyl-D-aspartate receptors, while aspartate shows an N-methyl-D-aspartate-like effect. The two excitatory amino acids glutamate and aspartate play a determinant role in the modulation of thalamic activity driven by corticothalamic projection.