Studies on the frequency and associations of equine leucocyte antigens in sarcoid and summer dermatitis

The equine leucocyte antigen (ELA) types and the clinical diagnosis for equine sarcoid and summer dermatitis were evaluated in 2026 horses representing five breeds. Data were analysed in unrelated animals and in family material. In the case of equine sarcoid, a strong association was observed between the ELA class II DW13 antigen and its effect on Swiss (cP < 0·001), French (cP < 0·0001) and Irish (cP < 0·01) Warmblood horses. The class I antigen A3 occurred more frequently in sarcoid-affected French horses (cP < 0·001). These results confirm our earlier findings (Gerber et al. 1988). Among Freiberger horses, which lack the ELA DW13 and A3 specificities, a breed-specific class I antigen, ABe108, displayed an increased frequency (cP < 0·05) in the affected group. Among Arabian horses, a tendency for increased frequency of the A1 antigen was observed in the affected animals, but the number of affected horses is too small for statistical significance. The Mendelian segregation in diseased half-siblings by ELA DW13 heterozygous stallions showed a strong association (P < 0·0001) between the inherited DW13 antigen and susceptibility to the sarcoid effect. In the case of summer dermatitis, previously published data (Marti et al. 1992) have been extended. The ELA types in four multiple-case families, founded by the same stallion, were analysed for an association with the effect of sarcoid. Eight out of nine ELA-typed affected offspring inherited the paternal haplotype A15, DW23 in contrast to nonaffected offspring where three out of 12 displayed these antigens (P < 0·005). Moreover, the ELA haplotypes of 11 out of 12 informative affected half-siblings sired by another stallion inherited the paternal haplotype A3, W12, DW23 (P < 0·05). Our findings demonstrate statistically significant associations between certain ELA antigens and two equine diseases. It is still unknown if the major histocompatibility complex (MHC) molecules themselves or another linked gene(s) play a role in the pathogenesis of these conditions.     

DNA sequence analysis of serologically detected ELA class II haplotypes at the equine DQP locus

The genetic diversity at the ELA DQβ locus was investigated using polymerase chain reaction and DNA sequencing. Based upon serological methods 16 class II homozygous animals were selected and their genomic DNA was used. A DQβ gene from an equine cDNA library was also sequenced. Our methology and the similarity between the genomic and the cDNA sequences suggest that the studied locus is expressed on equine lymphocytes. In the predicted amino acid sequence the most extensive variation is located at residues 56–60. The pattern of these five amino acids is strongly correlated to the serological ELA class II specificities (W13, W22, W23, Be200). The alleles corresponding to the W23 specificity are the most divergent among the equine DQβ alleles and also from other mammalian DQβ sequences.     

A computer algorithm to determine the recognition site of restriction enzymes

A new algorithm is proposed to determine the type-II restrictionendonucleases' recognition site knowing the digested DNA sequenceand fragment lengths in an actual case. The algorithm is implementedfor the Commodore 64 microcomputer. Received on January 6, 1987; accepted on June 19, 1987     

How the Visual Cortex Handles Stimulus Noise: Insights from Amblyopia

Adding noise to a visual image makes object recognition more effortful and has a widespread effect on human electrophysiological responses. However, visual cortical processes directly involved in handling the stimulus noise have yet to be identified and dissociated from the modulation of the neural responses due to the deteriorated structural information and increased stimulus uncertainty in the case of noisy images. Here we show that the impairment of face gender categorization performance in the case of noisy images in amblyopic patients correlates with amblyopic deficits measured in the noise-induced modulation of the P1/P2 components of single-trial event-related potentials (ERP). On the other hand, the N170 ERP component is similarly affected by the presence of noise in the two eyes and its modulation does not predict the behavioral deficit. These results have revealed that the efficient processing of noisy images depends on the engagement of additional processing resources both at the early, feature-specific as well as later, object-level stages of visual cortical processing reflected in the P1 and P2 ERP components, respectively. Our findings also suggest that noise-induced modulation of the N170 component might reflect diminished face-selective neuronal responses to face images with deteriorated structural information.     

Neurochemical evidence for two types of presynaptic alpha2-adrenoceptors

Neurochemical and pharmacological evidence has been obtained that noradrenergic varicosities (in mouse and rat vas deferens) and cholinergic varicosities (in the Auerbach's plexus) contain heterogenous alpha₂-adrenoceptors through which the release of [³H]noradrenaline and [³H]acetylcholine can be modulated. The quantitative data also support the hypothesis that different noradrenaline and xylazine sensitive alpha₂-adrenoceptors are present prejunctionally in the vas deferens and Auerbach's plexus preparations. Prazosin, although it has a presynaptic inhibitory effect on alpha₂-adrenoceptors of noradrenergic axon terminals, has no effect on cholinergic axon terminals. These data suggest that there are two different types of alpha₂-adrenoceptors at the presynaptic axon terminals.Special Issue Dedicated to Dr. Abel Lajtha     

Penicillin-binding proteins of protoplast and sporoplast membranes of Streptomyces griseus strains

Membrane-bound penicillin-binding proteins (PBPs) of two Streptomyces griseus strains that sporulate well in liquid and solid medium have been investigated during the course of their life-cycle. The PBP patterns were analyzed by sodium dodecylsulphate polyacrylamide-gel electrophoresis and fluorography. One strain (No. 45 H) has only a single band (mol wt: 27,000) in early log phase, and two additional PBPs of higher mol wt (69,000 and 80,000) in the late log phase. The other strain (No. 2682) possessed two bands with mol wts 27,000 and 38,000 which did not change during its vegetative phase. In strain No. 2682, a new PBP with a mol wt of 58,000 appeared in spore membranes while one of those (mol wt 38,000) present in mycelial membranes disappeared. Our results suggest that appearance of the new PBP in the spore may be associated with the sporulation process. The major PBP band (mol wt: 27,000) present in all stages of the life cycle of these strains, may be characteristic of S. griseus while the other PBPs reflect certain stages of the life cycle. A new method was developed for the production of spore protoplasts by consecutive enzymatic treatments.Abbreviation PBP penicillin-binding protein     

Formation of partially phosphorylated phosphorylase in isoproterenol stimulated rat hearts

Summary Phosphorylase ab hybrid was demonstrated in perfused rat hearts and during the in vitro conversion of purified rat heart phosphorylase b. Phosphorylase ab hybrid was determined in rat heart extracts by the activating effect of AMP in the presence of caffeine. These results were confirmed by the quantitative determination of incorporated ³²P in vitro and through the characteristic inhibition of ab hybrid by glucose-6-phosphate.As shown by our results, in aerobically perfused control hearts only the ab hybrid represents the active form of phosphorylase, its activity reaching about 20% of the total. In response to isoproterenol (5–1000 ng), the amount of ab hybrid rose to about 30–40%, preceding the rise of the a form, which increased in a dose-dependent manner up to 45% of the total.The great sensitivity of the ab form to AMP activation and glucose-6-phosphate inhibition supports its physiological significance in heart under in vivo conditions as well. Our results strongly suggest that the activity ratio -AMP/+AMP reflects rather the percentage ratio of phosphorylated subunits than that of the activated (partially or totally phosphorylated) phosphorylase molecules.     

Lack of association of bovine MHC class I alleles with carcass and reproductive traits

The present study was carried out to examine whether a relationship between bovine major histocompatibility complex (BoLA) class I alleles and carcass traits or reproductive performance exists in Braunvieh and Fleckvieh A1 (artificial insemination) bulls. The influence of BoLA class I (BOLA-A) alleles on deregressed breeding values for net growth rate, carcass index and thigh volume was assessed in Braunvieh crosses and Fleckvieh bulls with a gene substitution model. The reproductive traits: non-return rate and interval between first and last insemination of daughters (female fertility), as well as non-return rate of inseminated cows (male fertility), were only investigated in Fleckvieh animals. No influence of the BOLA-A region on the traits evaluated could be demonstrated. An improper, i.e. less restrictive analysis would have led to spurious results.     

Characterization of [3H]Met-Enkephalin-Arg6-Phe7 Binding to Opioid Receptors in Frog Brain Membrane Preparations

Abstract: A tritiated heptapeptide, [³H]Tyr-Gly-Gly-Phe-Met-Arg-Phe ([³H]Met-enkephalin-Arg⁶-Phe⁷), with high specific radioactivity has been synthesized in order to characterize its opioid binding activity to frog brain membrane fractions. The apparent K _D value of the radioligand calculated from homologous displacement experiments was 3.4 n M , and the maximal number of specific binding sites was 630 fmol/mg of protein. The K _D determined from equilibrium saturation binding studies was found to be 3.6 n M . However, the Hill coefficient was far below unity ( n _H = 0.43), which suggests the presence of a second, lower affinity binding site. The presence of this binding component is strengthened by the displacement experiments performed with levorphanol and some other ligands. It is assumed that the lower affinity site has no opiate character. The rank order of potency of the applied ligands in competing reversibly with [³H]Met-enkephalin-Arg⁶-Phe⁷ binding reflects a κ₂- and/or δ-subtype specificity of the heptapeptide. Binding to a κ₁ and/or μ site of opioid receptors is excluded, but the existence of a novel endogenous opiate receptor subtype for Met-enkephalin-Arg⁶-Phe⁷ in frogs cannot be ruled out. The [³H]Met-enkephalin-Arg⁶-Phe⁷ binding was inhibited by both sodium ions and GppNHp, which suggests the opioid agonist character of the heptapeptide.