Doppler detection of arterio-arterial anastomoses in monochorionic twins: feasibility and clinical application

The accuracy of in-vivo detection of arterio-arterial anastomoses (AAA) in monochorionic (MC) twins and its predictive value for twin-twin transfusion syndrome (TTTS) was assessed in 105 consecutive MC twins scanned at fortnightly intervals. AAA were sought using spectral and colour energy Doppler and ultrasound findings were compared with placental injection studies. AAA were identified in vivo in 59 (56%) pregnancies and at injection study in 68 (65%). The overall sensitivity and specificity was 85 and 97.3% respectively for the detection of AAA, Detection rates were higher at later gestations, with anterior placentae and with larger diameter AAA, The median insonation time to detect an AAA was 10 min (range 1-30), Where an AAA was identified, 15% of pregnancies (nine of 59) developed TTTS compared to 61% (28 of 46) when no AAA was seen (odds ratio 8.6). We conclude that AAA can be detected bl vivo with high sensitivity and specificity without undue prolongation of scanning times and have a role in risk stratification in the antenatal assessment of MC twins

The canine sodium/myo-inositol cotransporter gene: Structural organization and characterization of the promoter

The sodium/myo-inositol cotransporter (SMIT) is a plasma membrane protein catalyzing transfer of myoinositol into cells against a considerable concentration gradient using the electrochemical potential of sodium across the cell membrane, Transcription of the SMIT gene is markedly stimulated when cells are exposed to a hypertonic environment resulting in increased abundance of SMIT mRNA and increased SMIT activity, The increased accumulation of myo-inositol protects cells from the deleterious effects of hypertonicity, In an effort toward understanding transcriptional regulation, we cloned canine genomic DNA fragments containing the SMIT gene. The gene is 37 kb in size consisting of 2 exons and a large intron of 25 kb, The entire open reading frame is in the second exon, The promoter of the gene is highly active due to a GC-rich sequence. Ribonuclease protection assay using a riboprobe complementary to the 5' end of the gene confirmed that the promoter of the gene is stimulated by hypertonicity, The promoters and regulatory sequences of the SMIT gene and the betaine transporter gene, another gene regulated by hypertonicity, appear to be different.close1