TASK DEFINITION: Given an abstract, indicate which of the provided candidate titles (Option1 and Option2) best describes it (respond with the text of the title, not option1/2).
PROBLEM: Abstract: Injection of homologous DNA sequences into nuclei of cultured mammalian cells induces mutations in the cognate chromosomal gene. It appears that these mutations result from incorrect repair of a heteroduplex formed between the introduced and the chromosomal sequence. This phenomenon is termed 'heteroduplex induced mutagenesis'. The high frequency of these events suggests that this method may prove useful for introducing mutations into specific mammalian genes.
Which is the apt title for the abstract? option1: Introduction of homologous DNA sequences into mammalian cells induces mutations in the cognate gene. option2: Partially thrombosed giant intracranial aneurysms: correlation of MR and pathologic findings.

SOLUTION: Introduction of homologous DNA sequences into mammalian cells induces mutations in the cognate gene.

PROBLEM: Abstract: The effect of prolonged osmotic stimulation on the oxytocin (OT) mRNA levels of OT-producing neurons was investigated in separate hypothalamic nuclei of the rat. After drinking 2% NaCl for 2 weeks, a 2-fold increase in the OT mRNA content was found by Northern blot analysis of microdissected supraoptic nucleus (SON) and paraventricular nucleus (PVN). The same samples showed a similar change in vasopressin (VP) mRNA levels. This treatment resulted in a 70% depletion of both OT and VP from the neurointermediate lobe of the pituitary gland and a marked increase in OT and VP plasma levels. Analysis of the OT mRNA concentration by quantitative in situ hybridization showed that the SON, PVN, and anterior commissural nucleus responded similarly, with a 1.5-fold increase in OT mRNA after 7 days of osmotic stimulation. These results demonstrate that OT gene expression in the magnocellular neurons of the SON, PVN, and anterior commissural nucleus is sensitive to this osmotic stimulus, as is the VP gene of magnocellular neurons in the SON and PVN. The responsiveness of OT-producing neurons may point to a role for OT in the regulation of water and electrolyte balance.
Which is the apt title for the abstract? option1: Oxytocin gene expression in discrete hypothalamic magnocellular cell groups is stimulated by prolonged salt loading. option2: Locus of control as predictor of compliance and outcome in treatment of encopresis.

SOLUTION: Oxytocin gene expression in discrete hypothalamic magnocellular cell groups is stimulated by prolonged salt loading.

PROBLEM: Abstract: Diarrhea and a small bowel lesion similar to that reported in celiac sprue were observed in a patient who had been taking sulindac. Symptoms and biopsy abnormalities resolved completely after discontinuation of the medication and promptly recurred upon its re-administration. This report emphasizes the need to consider possible drug-related small bowel disease in the growing list of causes of the "flat" small intestinal mucosal lesion.
Which is the apt title for the abstract? option1: Sulindac-associated small bowel lesion. option2: Biotechnology insured: response to product liability [news]

SOLUTION:
Sulindac-associated small bowel lesion.