A polymorphic major histocompatibility complex class II‐like locus maps outside of both the chicken B‐system and Rfp‐Y‐system

Chickens have two major regions encoding major histocompatibility complex (MHC) class Iα genes and MHC class IIß genes, the serological and functional B‐system and the Rfp‐Y‐system. Recently, they have been shown to assort in a genetically independent way although still located on the same microchromosome. Moreover, the monomorphic MHC class IIα gene maps at a third locus located 5 c m from the nearest class IIß genes, located in the B‐system ( Kaufman et al., 1995 ). A pedigree family was studied in three generations in order to assign MHC class IIß restriction fragments observed in Southern blot analyses to either the B‐system, the Rfp‐Y‐system or the B‐Lα locus. In this study, we demonstrate by classical genetic testing of chickens within this fully pedigreed family the existence of an MHC class II‐like polymorphic restriction fragment that segregates independently of the B‐system, the Rfp‐Y‐system and of the B‐Lα locus.     

Differentiation between mouse-virulent and -avirulent strains of Toxoplasma gondii by a monoclonal antibody recognizing a 27-kilodalton antigen.

Using a murine monoclonal antibody, we were able to differentiate between mouse-virulent and -avirulent strains of Toxoplasma gondii. Monoclonal antibody TB6G5 was reactive with eight clinical mouse-avirulent isolates but not with mouse-virulent laboratory strains RH and BK. The antibody-reactive antigen was identified by indirect immunofluorescence and immunoblot as a 27-kDa cytoplasmic protein expressed by tachyzoites as well as by bradyzoites.     

The predictive value of dermatoglyphic anomalies in the diagnosis of fra(X)-positive Martin-Bell syndrome (MBS)

In a representative group of 160 institutionalized mentally retarded males without Down syndrome, prospective dermatoglyphic-cytogenetic studies were performed in order to assess the utility of the dermatoglyphic index system of Rodewald [1986] for an efficient ascertainment of patients with Martin-Bell syndrome (MBS). A negative (abnormal) score was found in 32 men (20 +/- 3%), 14 of whom (predictive value: 44 +/- 9%) were fra(X)-positive. This prevalence of 14/160 = 9 +/- 2% patients with fra(X)-positive MBS indicates that in our study most, if not all, MBS patients have been detected by the simple pre-screening of dermatoglyphics. In the MBS patients, there was no correlation between the dermatoglyphic scores and percentage of fra(X)-positive cells.     

Neuroimaging of NREM sleep in primary insomnia: a Tc-99-HMPAO single photon emission computed tomography study

STUDY OBJECTIVES: The objectives of this study were to: 1) demonstrate the feasibility of combining polysomnography and SPECT neuroimaging to study NREM sleep in primary insomnia and 2) evaluate possible functional CNS abnormalities associated with insomnia. DESIGN: Patients with insomnia and good sleeper controls were studied polysomnographically for three nights with a whole brain SPECT Scan of NREM sleep on Night 3. Groups were screened for medical/psychiatric history, substance use, and matched on age, body mass index, and education. SETTING: Sleep Research Laboratory and Nuclear Medicine Center PARTICIPANTS: Nine females, 5 patients with chronic psychophysiologic insomnia and 4 healthy good sleepers (mean age 36 years, SD 12, range 27-55). INTERVENTIONS: N/A MEASUREMENTS AND RESULTS: Tomographs of regional cerebral blood flow during the 1st NREM sleep cycle were successfully obtained. Contrary to our expectations, patients with insomnia showed a consistent pattern of hypoperfusion across all 8 pre-selected regions of interest, with particular deactivation in the basal ganglia (p=.006). The frontal medial, occipital, and parietal cortices also showed significant decreases in blood flow compared to good sleepers (p<.05). Subjects with insomnia had decreased activity in the basal ganglia relative to the frontal lateral cortex, frontal medial cortex, thalamus, occipital and parietal cortices (p<.05). CONCLUSIONS: This study demonstrated the feasibility of combining neuroimaging and polysomnography to study cerebral activity in chronic insomnia. These preliminary results suggest that primary insomnia may be associated with abnormal central nervous system activity during NREM sleep that is particularly linked to basal ganglia dysfunction.     

Early detection of COPD by high risk population spirometric screening

COPD is the most frequent chronic lung disease in Poland. The disease is however under-diagnosed, especially at the early stages. The aim of the study was to assess the efficacy of spirometric screening for COPD in middle aged smokers. Informations on causes and symptoms of COPD were disseminated in mass media in 14 large cities. Subject aged over 39 and with smoking history of > 10 packyears were invited for a free spirometry in local chest clinic. However, everyone attending had the spirometry performed. Spirometry was performed according to ATS recommendations. Airway obstruction (AO) was diagnosed when FEV1/FVC < 85% of N and categorised as mild (FEV1 > 70% of N), moderate (FEV1 50-69% of N) or severe (FEV1 < 50% of N). Spirometry was accompanied by an antismoking advice. RESULTS: 12.781 subjects were screened (mean age 52 +/- 12 years, 57% males). In 8.269 subjects who complied with inclusion criteria AO was diagnosed in 29.8% (mild in 10.9%, moderate in 12% and severe in 6.9%). In smokers < 40 years of age and a history of < 10 packyears AO was found in 8.8% (mild in 6.0%, moderate in 1.8% and severe in 1.0%). CONCLUSION: Mass spirometry is an effective and easy method for early detection of COPD.     

Use of antisera to the isolated alpha and beta subunits of C3 as probes to study functional sites present on particle-bound C3b but absent on native soluble forms of C3

The effect of antisera to the isolated alpha and beta chains of C3 on certain C3b-dependent reactions has been studied. C5-mediated haemolysis of EAC1423b was inhibited preferentially by antiserum to the alpha chain, whereas antiserum to the beta chain inhibited the formation of C3bBb. The anti-beta chain antiserum also stabilised C3bBbP, and rendered the enzyme relatively resistant to accelerated decay in the presence of factor H. These and previous findings that anti-alpha and anti-beta IgG bind to restricted subsets of antigenic determinants on C3/C3b suggest that these antisera affect C3b function through the binding of antibodies to active binding sites exclusively exposed by bound C3b. The anti-alpha and anti-beta antibody probes are currently being further developed to verify this interpretation.     

Immunochemical analysis of plasmid-encoded proteins released by enteropathogenic Yersinia sp. grown in calcium-deficient media.

Enteropathogenic Yersinia sp. releases plasmid-associated proteins of low molecular mass (26-67 kilodaltons) at 37 degrees C. In this study, the optimum conditions for the release of proteins were assessed and the released proteins (RPs) were analyzed for the manner of release, immunochemical characteristics, and the location of the genes necessary for their synthesis. Protein release was strongly enhanced when growth media were markedly depleted of calcium ions by precipitation with oxalate or chelation with EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid]. RP yields were greatest when Yersinia spp. were in the exponential growth phase. The RPs appeared to be released from the Yersinia spp. by secretion rather than by pinching off of membrane vesicles, because the RPs did not sediment during high-speed centrifugation nor were they contaminated to any significant degree with lipopolysaccharide. Moreover, immunoblot analysis revealed only traces of protein species related to RPs within the outer membranes of plasmid-positive Yersinia spp. grown at 37 degrees C under calcium-restricted conditions. Immunoblot studies also showed that the RPs of Y. enterocolitica serotypes O:3, O:8, and O:9 and the RP of Y. pseudotuberculosis serotype I are highly cross-reactive. Finally, the immunoprecipitates of the products of minicells which harbor Yersinia plasmids were used to demonstrate that at least three proteins immunochemically related to the released fraction were plasmid encoded. These results suggest that at least three of the RPs may be related to or identical with previously described plasmid-encoded Yersinia outer membrane proteins.     

Molecular cloning, genomic structure and localization in a blood stage antigen of Plasmodium falciparum characterized by a serine stretch

Two short DNA segments were isolated by screening of a lambda gt11 library from Plasmodium falciparum schizont cDNA with an antiserum against the 140 kDa protein, which confers protective immunity to monkeys. The segments were used to identify a genomic fragment which carries the entire coding sequence for a protein of 113 kDa characterized by a stretch of serine residues (SERP I). We present the complete nucleotide and deduced amino acid sequence as well as the structure of the SERP I gene. The gene consists of four exons interrupted by three short introns located at the amino-terminal half. Exon 1 and the first part of exon 2 code for hydrophobic amino acids of a putative signal sequence. Exon 2 contains two repetitive segments, the first encoding six glycine rich octapeptides and a second region coding for 37 consecutive serine residues. Southern blot analysis demonstrated the conservation of the SERP I gene in four different parasite strains. SERP I could be localized in the parasitophorous vacuole and in the surrounding membranes. We discuss the relationship of this protein to the recently described P126 polypeptide and the possible role of this antigen as a vaccine candidate.