Evidence for stable transformation of wheat by floral dip in Agrobacterium tumefaciens.

Hexaploid wheat, one of the world's most important staple crops, remains a challenge for genetic transformation. We are developing a floral transformation protocol for wheat that does not require tissue culture. This paper presents three transformants in the hard red germplasm line Crocus that have been characterized thoroughly at the molecular level over three to six generations. Wheat spikes at the early boot stage, i.e. the early, mid or late uninucleate microspore stages, were immersed in an infiltration medium of strain C58C1 harboring pDs(Hyg)35S, or strain AGL1 harboring pBECKSred. pDs(Hyg)35S contains the NPTII and hph selectable markers, and transformants were detected using paromomycin spray at the whole plant level, NPTII ELISAs, or selection on medium with hygromycin. Strain AGL1, harboring pBECKSred, which contains the maize anthocyanin regulators, Lc and C1, and the NPTII gene, was also used to produce a Crocus transformant. T1 and T2 seeds with red embryos were selected; T1 and T2 plants were screened by sequential tests for paromomycin resistance and NPTII ELISAs. The transformants were low copy number and showed Mendelian segregation in the T2. Stable transmission of the transgenes over several generations has been demonstrated using Southern analysis. Gene expression in advanced progeny was shown using Reverse Transcriptase-PCR and ELISA assays for NPTII protein expression. This protocol has the potential to reduce the time and expense required for wheat transformation.

Prevalence and determinants of valvulopathy in patients treated with dexfenfluramine.

BACKGROUND: Valve regurgitation has been associated with dexfenfluramine, but its prevalence and severity are uncertain. Additional factors that may contribute to valve regurgitation in patients exposed to this drug are poorly understood. METHODS AND RESULTS: Echocardiography was performed on subjects recruited from 26 prescribing sites in 15 states. The total sample of 412 subjects included 172 dexfenfluramine patients and 172 unexposed controls matched for age, sex, and body mass index and 68 unmatched subjects meeting the same entry criteria (51 dexfenfluramine patients and 17 controls). Mean treatment duration was 6.9 months; mean interval from treatment discontinuation to echocardiogram was 8.5 months. Each echocardiogram was interpreted independently by 3 echocardiographers. FDA-grade regurgitation (at least mild aortic regurgitation or at least moderate mitral regurgitation) was significantly more frequent in dexfenfluramine patients (7.6% versus 2.1% for controls; P=0.01; odds ratio, 3.82). This difference was primarily due to more frequent mild aortic regurgitation in dexfenfluramine patients (6.3% versus 1.6% in controls; P<0.02; odds ratio, 4.15). No differences were found in sclerosis or mobility for either the aortic or mitral valve. Factors independently related to FDA-grade regurgitation or any grade of aortic regurgitation were older age, higher diastolic blood pressure at the time of echocardiography, and shorter time from drug discontinuation to echocardiogram. CONCLUSIONS: Dexfenfluramine use is associated with an increase in the prevalence of abnormal valve regurgitation. Age and blood pressure may also affect the prevalence of regurgitation. Dexfenfluramine-related valve regurgitation may regress after drug discontinuation.