Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability

X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.      

Seroprevalence of Ehrlichia canis and of Canine Granulocytic Ehrlichia Infection in Dogs in Switzerland

Serum samples from 996 dogs in Switzerland were examined for antibodies to Ehrlichia canis and to the agent causing canine granulocytic ehrlichiosis (CGE). Ehrlichiosis, borreliosis, and systemic illness not associated with ticks were suspected in 75, 122, and 157 of these dogs, respectively. The remainder of the serum samples were obtained from clinically healthy dogs which resided north (n = 235) or south (n = 407) of the Alps. The serum samples were tested by an indirect immunofluorescence technique for antibodies to the two agents incriminated, E. canis and Ehrlichia phagocytophila, a surrogate marker of the agent of CGE. Twenty-two of 996 (2.2%) serum samples had antibodies to E. canis and were distributed as follows: 20 of 75 (26.7%) samples from dogs suspected of having ehrlichiosis, 1 of 122 (0.8%) from dogs suspected of having borreliosis, and 1 of 407 (0.2%) from healthy dogs which resided south of the Alps. Of the 75 (7.5%) serum samples that had antibodies to E. phagocytophila, significantly more samples were from ill dogs than from healthy dogs. Among the sera from healthy dogs, antibodies to E. phagocytophila were significantly more prevalent in the north. Because seropositive dogs had a history of travel outside Switzerland and because Rhipicephalus sanguineus is found exclusively south of the Alps, it was presumed that, in contrast to the agent of CGE, E. canis is not indigenous to Switzerland.     

PIGQ glycosylphosphatidylinositol‐anchored protein deficiency: Characterizing the phenotype

PIGQ (OMIM *605754) encodes phosphatidylinositol glycan biosynthesis class Q (PIGQ) and is required for proper functioning of an N‐acetylglucosamine transferase complex in a similar manner to the more established PIGA, PIGC, and PIGH. There are two previous patients reported with homozygous and apparently deleterious PIGQ mutations. Here, we provide the first detailed clinical report of a patient with heterozygous deleterious mutations associated with glycosylphosphatidylinositol‐anchored protein (GPI‐AP) biosynthesis deficiency. Our patient died at 10 months of age. The rare skeletal findings in this disorder expand the differential diagnosis of long bone radiolucent lesions and sphenoid wing dysplasia. This clinical report describes a new and rare disorder—PIGQ GPI‐AP biosynthesis deficiency syndrome.     

Alternating copolymerization of butadiene and propene with the catalyst VO(ONeo)2 Cl/Al(i-C4H9)3, 1

The influence of basic reaction parameters—the ratio of catalyst components, the composition of the monomer mixture and the temperature—on the progress of the copolymerization, the molecular weight and the molecular weight distribution as well as on the composition of the copolymers obtained is reported. Conversion data for the variation of the mole ratio of comonomers show a maximum for an [Al]/[V] mole ratio of approximately 7, whereas the molecular weight of copolymers is not significantly influenced. An increase in the molecular weight of the copolymers can be obtained by an increase of butadiene content in the monomer mixture. However, there is also an increasing incorporation of butadiene into the copolymer. Raising the temperature from ?60°C to 0°C results in a significant decrease in molecular weight, whereas the composition of the copolymers is not significantly changed.     

Effects of topography and composition of titanium surface oxides on osteoblast responses

To investigate the roles of composition and characteristics of titanium surface oxides in cellular behaviour of osteoblasts, the surface oxides of titanium were modified in composition and topography by anodic oxidation in two kinds of electrolytes, (a) 0.2 M H(3)PO(4), and (b) 0.03 M calcium glycerophosphate (Ca-GP) and 0.15 M calcium acetate (CA), respectively. Phosphorus (P: ca.10at%) or both calcium (Ca: 1-6at%) and phosphorus (P: 3-6at%) were incorporated into the anodized surfaces in the form of phosphate and calcium phosphate. Surface roughness was slightly decreased or enhanced (R(a) in the range of 0.1-0.5 microm) on the anodized surfaces. The geometry of the micro-pores in the anodized surfaces varied with diameters up to 0.5 microm in 0.2 M H(3)PO(4) and to 2 microm in 0.03 M Ca-GP and 0.15 M CA, depending on voltages and electrolyte. Contact angles of all the anodic oxides were in the range of 60-90 degrees. Cell culture experiments demonstrated absence of cytotoxicity and an increase of osteoblast adhesion and proliferation by the anodic oxides. Cells on the surfaces with micro-pores showed an irregular and polygonal growth and more lamellipodia, while osteoblasts on the titanium surface used as a control or on anodic oxides formed at low voltages showed many thick stress fibres and intense focal contacts. Alkaline phosphatase (ALP) activity of the cells did not show any correlation with surface characteristics of anodic oxides.     

Serum contains a potent factor that decreases β-adrenergic receptor-stimulated L-type Ca2+ current in cardiac myocytes

L-type Ca²⁺ current (I _Ca) was measured in cultured atrial myocytes from hearts of adult guinea-pigs using whole-cell voltage clamp. Potentiation of I _Ca induced by -adrenergic stimulation (isoprenaline 2· 10^–7 M) could be completely antagonized by diluted sera (1100 v/v). Half-maximal inhibition of -receptorstimulated I _Ca occurred at about 11000. Basal I _Ca was not affected by serum. Atropine in a concentration (10^–6M) that completely antagonized the anti-adrenergic effect of acetylcholine (ACh, 2·10^–6 M) did not interfere with the effect of serum. In cells dialysed with cyclic adenosine monophosphate (cAMP)-containing (10^–4 M) pipette solution, potentiated I _Ca was insensitive to both ACh and serum. Preincubation of the myocytes with pertussis toxin almost completely abolished the anti-adrenergic effects of both ACh and serum. The potency of serum was not reduced by dialysis. It is concluded that serum contains a factor which, like ACh, inhibits -receptor-stimulated adenylyl cyclase via G_iprotein.A preliminary report of this work has appeared in abstract form [11]