脂布福吉宁的心脏毒性作用:电生理学证据(英文)

脂布福吉宁是从传统中药蟾酥中分离的单一化合物。长期以来,蟾酥制品广泛应用于中国、日本及亚洲其他国家。但是,近来在美国出现一些有关蟾酥及其药物制剂引起中毒的报告。如洋地黄一样,脂布福吉宁也具有药理和毒理作用。根据我们的实验结果,高浓度脂布福吉宁,蟾酥的主要成分之一,可以引起离体心肌细胞和在体心脏的延时性后去极化及触发性心律失常。本文对引起毒性的可能机制及治疗心律失常的可能性也进行了讨论。     

HOMOCYSTINURIA: A REPORT OF TWO AUSTRALIAN FAMILIES*

Homocystinuria, an inborn error in the metabolism of the sulphur containing amino-acids, is characterized by the presence of the amino-acid homocystine in the urine. The clinical features of the disease are mild in infancy but become progressively more severe in childhood. Ectopia lentis, mental retardation, skeletal deformity and a tendency to intra-vascular thrombosis are features of the established disease. Two Australian families with 5 living affected members, illustrating the evolution of the disease are described. The condition follows a Mendelian recessive mode of inheritance. The diagnosis can be suspected by simple biochemical screening tests applied to the urine. Treatment by restriction of dietary methionine is under trial.     

CLINICAL PROFILES OF ATYPICAL CHROMOSOME-G ANOMALIES

778 patients with Down's syndrome have been assessed at this hospital in the past 81/2 years and chromosome analyses were performed on 350; 9.7% had atypical karyotypes and these will be discussed in detail; the remaining 90.3% had standard trisomy-G karyotypes with parents with normal karyotypes or whose parents had not had chromosome analyses. Of the 34 atypical cases, 10 have G/G translocations, 7 have a D/G translocation, 11 are mosaic mongols, 5 are standard trisomy-G with one parent with an abnormal chromosome pattern, and one a trisomy-G with a D/D translocation.     

Design of peptides: synthesis,crystal structure and molecular conformation of N-Boc-L-Val-δPhe-L-Ile-OCH3

The dehydro-peptide Boc-L-Val-δPhe-L-Ile-OCH₃ was synthesized by the azlactone method in the solution phase. The peptide crystallized from a methanol/dimethyl sulfoxide (95:5) mixture in space group P6₁, with a=b= 15.312(1), c= 22.164(5) Å. The structure was determined by direct methods and refined to an R value of 0.098 for 1589 observed reflections [I≥ 1.5 σ(I)]. The peptide adopts an S-shaped conformation with torsion angles: ø₁=-127(1), ψ₁= -44(1), ø₂, = 67(1), ψ₂, = 37(1), ø₃,=-82(1)°. The side-chain torsion angles in δPhe of X¹₂= 1(2), X^2.1₂= 7(2) and X_2.22 = 177(1)° indicate that the δPhe residue is essentially planar. In valyl residue the two side-chain torsion angles are X¹₁= -65(1) and X²₁= 177(1), whereas the torsion angles in Ile are X^1,1₃= 72(2), X^1,2₃= -159(2), X²₃= 150(2)°. This is the first peptide which does not adopt a folded conformation for a sequence with a δPhe at the (i+ 2) position. The molecular packing in the crystals is stabilized by several hydrogen bonds: N₁-H₁?O₁’= 2.77(1) Å, N₂-H₂?O₁’= 2.95(1) Å, N₃-H₃?O₂=2.85(1) Å and a possible weak interaction N₂-H₂?O₁’3.29(1) Å- within the columns of molecules along the c-axis and van der Waals forces between the columns. © Munksgaard 1996.     

An Asian–Native American paternal lineage identified by RPS4Y resequencing and by microsatellite haplotyping

Human paternal population history was studied in 9 populations [three Native American, three Asian, two Caucasian and one African-derived sample(s)] using sequence and short tandem repeat haplotype diversity within the non-pseudoautosegmal region of the Y chromosome. Complete coding and additional flanking sequences (949 base pairs) of the RPS4Y locus were determined in 59 individuals from three of the populations, revealing a nucleotide diversity of 0.0147%, consistent with previous estimates from Y chromosome resequencing studies. One RPS4Y sequence variant, 711C>T, was polymorphic in Asian and Native American populations, but not in African and Caucasian population samples. The RPS4Y 711C>T variant, a second unique sequence variant at DYS287 and nine Y chromosome short tandem repeat (YSTR) loci were used to analyze the evolution of Y chromosome lineages. Three unambiguous lineages were defined in Asian, Native American and Jamaican populations using sequence variants at RPS4Y and DYS287 . These lineages were independently supported by the haplotypes defined solely by YSTR alleles, demonstrating the haplotypes constructed from YSTRs can evaluate population diversity, admixture and phylogeny.