Transgenic mouse models of Alzheimer's disease: how useful have they been for therapeutic development?

Transgenic mice have been created in an attempt to generate models of human Alzheimer's disease, but success has been partial and unpredictable. The overall aim of this paper is to illustrate how genomics can be used in translational research, turning genetic information in the form of pathogenic mutations into clinically useful drugs against a major human disease. This paper will illustrate how genetic information allows researchers to dissect the aetiology of a disease and then replicate the disease in vivo through the process of transgenesis. The limitations of recreating a condition like Alzheimer's disease in a transgenic mouse, how far the mice have advanced understanding of the disease and how useful they have been for the development of therapeutics will then be discussed.     

Novel interleukin-1 receptor antagonist exon polymorphisms and their use in allele-specific mRNA assessment

A variable number of tandem repeats (VNTR) polymorphism has been described in intron 2 of the interleukin-1 receptor antagonist gene. Allele 2 of this polymorphism is associated with many chronic inflammatory diseases. Using direct sequencing of polymerase chain reaction products from individuals of known genotype for the VNTR, we have identified four single base change polymorphisms in exons 1_ic and 2 and one upstream of exon 1_ic, all of which are probably in linkage disequilibrium with the intron 2 VNTR. The exonic polymorphisms do not alter the encoded amino acid sequence. Using the exon 2 polymorphism as a marker for the intron 2 disease-associated allele, we have been able to analyse allele-specific mRNA in heterozygotic keratinocyte cell lines. The disease-associated allele shows no difference from other alleles in this cell type with respect to mRNA accumulation. Received: 17 July 1995 / Revised: 4 December 1995     

Raman and infrared spectroscopy of the oxo-bridged iron(III) complex, [Cl3Fe-O-FeCl3]-2 as a spectroscopic model for the oxo bridge in hemerythrin and ribonucleotide reductase

Vibrational spectroscopic data were collected on the salt [C5H6N]2[Cl3FeOFeCl3] . C5H5N, which has previously been structurally characterized by X-ray crystallography. The modes associated with the oxo bridge were identified by experiments on the 18O-containing species. Spectra for the mu-16O complex contain Raman bands at 870, 458, and 203 cm-1 that shift to 826, 440, and 198 cm-1 in the mu-18O complex. These are respectively assigned to the asymmetric, symmetric, and angle deformations of the bent Fe-O-Fe moiety. A normal mode vibration analysis based on a simple valence force field for the Fe-O-Fe portion of the molecule provides surprisingly good agreement with these experimental frequencies and their assignments. The vibrational data for this simple inorganic complex confirm the assignment of a resonance Raman band around 500 cm-1 in the oxygen-carrying protein hemerythrin and enzyme ribonucleotide reductase as the symmetric stretch of an oxo bridge between two iron(III) centers.     

Dopamine Agonist-Induced Inhibition of Neurotransmitter Release from the Awake Squirrel Monkey Putamen as Measured by Microdialysis

Abstract: Male squirrel monkeys ( Saimiri sciureus ) were surgically prepared with cranial guide cannulae for acute microdialysis sampling of the putamen nucleus, a dopamine (DA)-rich brain region. On the day of an experiment, an animal was placed in a Plexiglas restraining chair and a microdialysis probe was inserted through the guide into the putamen. Perfusates of artificial cerebrospinal fluid were collected every 20 min over several hours and analyzed via HPLC with electrochemical detection. DA D₂/D₃ agonist drugs were administered either orally (p.o.) or subcutaneously (s.c.), and changes in levels of DA in the dialysates were measured. All of the drugs tested, i.e., quinpirole (0.5 mg/kg p.o.), talipexole (0.75 mg/kg p.o. or s.c.), and PD 135222 (7 mg/kg p.o.), decreased spontaneous DA overflow by ∼40–50% during the first 2 h following dosing. In animals that routinely underwent the microdialysis procedure up to 23 times over a 2-year period, there was neither an appreciable change in basal DA overflow nor a significant change in the magnitude of drug response. These data suggest that DA D₂/D₃ agonists attenuate DA neuronal overflow in the primate brain, similar to effects seen in rodents. Furthermore, these results also demonstrate the utility of repeated intracerebral microdialysis as a tool to monitor dynamic changes in neurochemical activity in monkeys over a prolonged period of time.     

Comparison of industrial yeast strains for fermentation of spent sulphite pulping liquor fortified with wood hydrolysate

Ethanol production from spent sulphite pulping liquor (SSL) was compared for four different yeasts. A second strain of S. cerevisiae as well as a 2-deoxyglucose-resistant strain formed through protoplast fusions between S. uvarum and S. diastaticus produced up to 27% more ethanol from SSL fortified with hydrolysis sugars than was produced by S. cerevisiae. The incremental improvement in ethanol yield appeared to vary with the degree of fortification, ranging from 5.8% for unfortified SSL, to 27% for the highest level of fortification tested. Decreasing fermentation rates were observed for SSL fortified with glucose, mannose and galactose, respectively. Sugar uptake rates in SSL fortified with glucose, galactose and mannose were 6.8, 2.8 and 2.0 g L⁻¹ h⁻¹, respectively. However, when these sugars were fermented along with a glucose cosubstrate, the rate at which the combined glucose/mannose medium was fermented was nearly identical to that of the glucose control. Received 18 April 1996/ Accepted in revised form 27 August 1996     

Microcell-mediated cotransfer of genes specifying methotrexate resistance, emetine sensitivity, and chromate sensitivity with Chinese hamster chromosome 2.

Many selectable mutants of somatic Chinese hamster cells have been described, but very few of the mutations have been mapped to specific chromosomes. We have utilized the microcell-mediated gene transfer technique to establish the location of three selectable genetic markers on chromosome 2 of Chinese hamster. Microcells were prepared from the methotrexate-resistant MtxRIII line of Flintoff et al. (Somatic Cell Genet. 2:245-261, 1976) and fused to wild-type CHO cells, and microcell hybrids (transferants) were selected in medium containing methotrexate. All transferants were karyotyped and found to contain a marker chromosome from the donor MtxRIII line. This marker chromosome, called 2p-, consisted of a chromosome 2 with a reduced short arm resulting from a reciprocal translocation between 2p and 5q. In experiments utilizing emetine-resistant (Emtr) or chromate-resistant (Chrr) recipient cells it was found that the emt+ and chr+ wild-type genes were cotransferred with the 2p- chromosomes. Karyotype analysis of several transferants with rearranged or broken 2p- markers allowed regional localization of the emt and chr loci to the proximal third of the long arm and localization of the gene or genes conferring methotrexate resistance to the short arm. These results confirm our earlier assignment of the emt and chr loci to chromosome 2 in Chinese hamster.