Asymmetric catalytic conjugate addition of acetaldehyde to nitrodienynes/nitroenynes: applications to the syntheses of (+)-α-lycorane and chiral ß-alkynyl acids.

The catalytic enantioselective conjugate addition of acetaldehyde to polyconjugated substrates, nitrodienynes and nitroenynes, has been accomplished using organocatalysis. Various functionalized 1,3-enynes and propargylic compounds were obtained in moderate to good yields with high enantioselectivity. The synthetic utilities of the conjugate addition reactions have been highlighted in the concise total synthesis of (+)-α-lycorane and the metal-free synthesis of chiral ß-alkynyl acids.

Spinal extradural meningeal cysts: an MRI evaluation of a case series and literature review.

STUDY DESIGN: Case series and literature review. OBJECTIVE: To analyze the characteristics of extradural spinal meningeal cysts (SMCs) by magnetic resonance imaging (MRI) and discuss their classifications and etiology, as well as exploring the choice of treatment. SUMMARY OF BACKGROUND DATA: Spinal extradural meningeal cysts are a rare type of SMC. They are also known as extradural/epidural spinal arachnoid cysts. According to Nabors' classification, they belong to the category of types I and II meningeal cysts. The etiology of spinal extradural cysts remains unclear. MATERIALS AND METHODS: We retrospectively analyzed the MRI scans of 18 cases of extradural arachnoid cyst, which were consecutively treated surgically at our institutions between June 1990 and November 2009. All cases were confirmed by surgery. Disonics 0.35T and Philips Gyroscan Intera 1.5T scanner with surface coils were used for patient scanning. MRI examination included routine sagittal T1-weighted/spin-echo , sagittal, and transverse T2-weighted scanning. The above scans were repeated after the administration of intravenous contrast 3 medium (gadolinium) in 12 patients. RESULTS: Seven of the 18 cases were located in the middle and lower thoracic spine, 3 in the lumbar spine, and 8 in the thoracolumbar junction. All cystic lesions were isointense compared with cerebrospinal fluid on the T1 and T2-weighted images. The lesions showed no enhancement after gadolinium administration. CONCLUSIONS: MRI had great sensitivity to and specificity for extradural arachnoid cysts and seemed to be the diagnostic procedure of choice before and after surgery. Accurate understanding of MRI features helps clinicians make preoperative diagnoses and guides the operation. The definitive treatment of SMCs involves total removal of the cyst and repair of the dural defect.

Skeletal defects in paternal uniparental disomy for chromosome 14 are re-capitulated in the mouse model (paternal uniparental disomy 12).

Human paternal uniparental disomy for chromosome 14 (upd(14)pat) presents with skeletal abnormalities, joint contractures, dysmorphic facial features and developmental delay/mental retardation. Distal human chromosome 14 (HSA14) is homologous to distal mouse chromosome 12 (MMU12) and both regions have been shown to contain imprinted genes. In humans, consistent radiographic findings include a narrow, bell-shaped thorax with caudal bowing of the anterior ribs, cranial bowing of the posterior ribs and flaring of the iliac wings without shortening or dysplasia of the long bones. Mice with upd(12)pat have thin ribs with delayed ossification of the sternum, skull and feet. In both mice and humans, the axial skeleton is predominantly affected. We hypothesize that there is an imprinted gene or genes on HSA14/MMU12 that specifically affects rib/thorax development and the maturation of ossification centers in the sternum, feet and skull with little effect on long bone development.