Formal Total Synthesis of Atropurpuran.

Atropurpuran, isolated from the roots of Aconitum hemsleyanum, is a non-alkaloidal diterpene which possesses a unique pentacyclic skeleton that contains an unprecedented tetracyclo[5.3.3.04,9.04,12]tridecane unit. We report herein the formal total synthesis of atropurpuran. The key features of our synthetic route are a high diastereoselective construction of the tri- and tetrasubstituted carbons (i.e., C4, C5, C10, and C20) through an Yb-catalyzed Mukaiyama aldol reaction in an aqueous medium and a one-pot operation including an intramolecular Diels-Alder reaction/ring-closing metathesis to construct the unique pentacyclic skeleton of atropurpuran.

Genetic screening of spinal muscular atrophy using a real-time modified COP-PCR technique with dried blood-spot DNA.

BACKGROUND: Spinal muscular atrophy (SMA) is a common neuromuscular disorder caused by mutations in SMN1. More than 95% of SMA patients carry homozygous SMN1 deletion. SMA is the leading genetic cause of infant death, and has been considered an incurable disease. However, a recent clinical trial with an antisense oligonucleotide drug has shown encouraging clinical efficacy. Thus, early and accurate detection of SMN1 deletion may improve prognosis of many infantile SMA patients. METHODS: A total of 88 DNA samples (37 SMA patients, 12 carriers and 39 controls) from dried blood spots (DBS) on filter paper were analyzed. All participants had previously been screened for SMN genes by PCR restriction fragment length polymorphism (PCR-RFLP) using DNA extracted from freshly collected blood. DNA was extracted from DBS that had been stored at room temperature (20-25°C) for 1week to 5years. To ensure sufficient quality and quantity of DNA samples, target sequences were pre-amplified by conventional PCR. Real-time modified competitive oligonucleotide priming-PCR (mCOP-PCR) with the pre-amplified PCR products was performed for the gene-specific amplification of SMN1 and SMN2 exon 7. RESULTS: Compared with PCR-RFLP using DNA from freshly collected blood, results from real-time mCOP-PCR using DBS-DNA for detection of SMN1 exon 7 deletion showed a sensitivity of 1.00 (CI [0.87, 1.00])] and specificity of 1.00 (CI [0.90, 1.00]), respectively. CONCLUSION: We combined DNA extraction from DBS on filter paper, pre-amplification of target DNA, and real-time mCOP-PCR to specifically detect SMN1 and SMN2 genes, thereby establishing a rapid, accurate, and high-throughput system for detecting SMN1-deletion with practical applications for newborn screening.

New, Improved Version of the mCOP-PCR Screening System for Detection of Spinal Muscular Atrophy Gene (SMN1) Deletion.

BACKGROUND: Spinal muscular atrophy (SMA) is a frequent autosomal recessive disorder, characterized by lower motor neuron loss in the spinal cord. More than 95% of SMA patients show homozygous survival motor neuron 1 (SMN1) deletion. We previously developed a screening system for SMN1 deletion based on a modified competitive oligonucleotide priming-PCR (mCOP-PCR) technique. However, non-specific amplification products were observed with mCOP-PCR, which might lead to erroneous interpretation of the screening results. AIM: To establish an improved version of the mCOP-PCR screening system without non-specific amplification. METHODS: DNA samples were assayed using a new version of the mCOP-PCR screening system. DNA samples had already been genotyped by PCR-restriction fragment length polymorphism (PCR-RFLP), showing the presence or absence of SMN1 exon 7. The new mCOP-PCR method contained a targeted pre-amplification step of the region, including an SMN1-specific nucleotide, prior to the mCOP-PCR step. mCOP-PCR products were electrophoresed on agarose gels. RESULTS: No non-specific amplification products were detected in electrophoresis gels with the new mCOP-PCR screening system. CONCLUSION: An additional targeted pre-amplification step eliminated non-specific amplification from mCOP-PCR screening.

Analysis of cationic structure in some room-temperature molten fluorides and dependence of their ionic conductivity and viscosity on hydrofluoric acid concentration.

To understand the ionic and nonionic species in (CH(3))(4)NF·mHF, (CH(3))(3)N·mHF, (C(2)H(5))(4)NF·mHF, and (C(2)H(5))(3)N·mHF melts, the structures of these melts were investigated by infrared spectroscopy, NMR, and high-energy X-ray diffraction. Infrared spectra revealed that three kinds of fluorohydrogenate anions, (FH)(n)F(-) (n = 1, 2, and 3), and molecular hydrofluoric acid (HF) are present in every melt. Ionic conductivity and viscosity of these melts were measured and correlated with their cationic structure. The ionic conductivity of the R(4)N(+)-systems was higher than that of corresponding R(3)NH(+)-systems because a strong N-H···F(HF)(n) interaction prevents the motion of R(3)NH(+) cations in the R(3)N·mHF melts. (CH(3))(4)N(+) and (CH(3))(3)NH(+) cations gave higher ionic conductivity than (C(2)H(5))(4)N(+) and (C(2)H(5))(3)NH(+) cations, respectively, because the ionic radii of former cations were smaller than those of latter. It was concluded that these effects on ionic conductivity can be explained by the cationic structure and the concentration of molecular HF in the melts.

A classical-map simulation of two-dimensional electron fluid: an extension of classical-map hypernetted-chain theory beyond the hypernetted-chain approximation.

A method for numerically simulating quantum systems is proposed and applied to the two-dimensional electron fluid at T = 0. This method maps quantum systems onto classical ones in the spirit of the classical-map hypernetted-chain theory and performs simulations on the latter. The results of the simulations are free from the assumption of the hypernetted-chain approximation and the neglect of the bridge diagrams. A merit of this method is the applicability to systems with geometrical complexity and finite sizes including the cases at finite temperatures. Monte Carlo and molecular dynamics simulations are performed corresponding to two previous proposals for the 'quantum' temperature and an improvement in the description of the diffraction effect. It is shown that one of these two proposals with the improved diffraction effect gives significantly better agreement with quantum Monte Carlo results reported previously for the range of 5≤r(s)≤40. These results may serve as the basis for the application of this method to finite non-periodic systems like quantum dots and systems at finite temperatures.