Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Abstract: Allelic sequence variation has been analysed by synthetic oligonucleotide hybridization probes which can detect single base substitutions in human genomic DNA. An allele-specific oligonucleotide (ASO) will only anneal to sequences that match it perfectly, a single mismatch being sufficient to prevent hybridization under appropriate conditions. To improve the sensitivity, specificity and simplicity of this approach, we used the polymerase chain reaction (PCR) procedure to enzymatically amplify a specific segment of the beta-globin or HLA-DQ alpha gene in human genomic DNA before hybridization with ASOs. This in vitro amplification method, which produces a greater than 10(5)-fold increase in the amount of target sequence, permits the analysis of allelic variation with as little as 1 ng of genomic DNA and the use of a simple 'dot blot' for probe hybridization. As a further simplification, PCR amplification has been performed directly on crude cell lysates, eliminating the need for DNA purification.
Alleles

Abstract: We have determined the structures of high mannose (Man) oligosaccharide units of the alpha- and beta-subunits of mouse TSH heterodimers and of free alpha-subunits. Mouse thyrotropic tumor tissue, or pituitaries from euthyroid or hypothyroid mice, were incubated with D-[2-3H]Man, homogenized, and incubated in the presence or absence of pH 3 buffer to dissociate heterodimers. Highly enriched TSH beta-subunits, or TSH heterodimers, were obtained using anti-TSH beta serum and free alpha-subunits were subsequently obtained using anti-LH alpha-serum. High Man units released by endoglycosidase H were analyzed by paper chromatography. At 1 and 3 h oligosaccharides with 8 or 9 Man residues predominated in all subunits. In all three tissue types, units with 9 Man tended to accumulate in TSH beta-subunits, whereas Man-trimming from Man9GlcNAc to Man8GlcNAc proceeded more rapidly in TSH alpha-subunits, and in free alpha-subunits. The rate of TSH beta-subunit processing was also a function of tissue type; the rate in euthyroid pituitary tissue equaled that in tumor tissue and was greater than that in hypothyroid pituitary tissue, suggesting that processing may be physiologically regulated. Hypothyroid calf serum slowed TSH alpha-subunit processing in euthyroid pituitaries. Thus, the previously reported slower processing of Man9GlcNAc to Man8GlcNAc in heterodimers as compared to free alpha-subunits is in large part due to accumulation of Man9GlcNAc in TSH beta-subunits.
Animal

Abstract: Stress fracture of the fourth vertebral arch occurred in a 21-year-old woman with a benign osteopetrosis. The fracture healed in three months after application of a body cast. It seems likely that the osteopetrotic bone resists force, in parallel with the cortical layer, but is fragile to forces at right angles to the plane of the cortical layer.

Adult

