槲寄生化学成分的研究——Ⅵ.槲寄生新甙Ⅵ中手性碳的绝对构型测定

本文采用降解及与已知构型的化合物进行对比的方法,确定了新黄酮甙槲寄生新甙Ⅳ中酸性部分手性碳的绝对构型     

Glanzmann's thrombasthenia caused by homozygosity for a splice defect that leads to deletion of the first coding exon of the glycoprotein IIIa mRNA

Glanzmann's thrombasthenia (GT) is the result of the absence or of an altered and dysfunctional expression on the platelet membrane of the fibrinogen receptor (glycoprotein [GP] IIb/IIIa complex). Various molecular genetic mechanisms have been found to be responsible for this inherited disease. In a patient with a severe type of GT, we have found a splice variant in the GP IIIa gene that leads to premature chain termination. Immunoprecipitation experiments, using monoclonal antibodies specific for GP IIb/IIIa, showed that GP IIb/IIIa was not detectable on the platelet membrane. Amplification of reversely transcribed platelet GP IIIa mRNA by the polymerase chain reaction and subsequent sequence analysis showed a 86-bp deletion, which corresponds to exon i of the GP IIIa gene. This deletion results in a shift of the reading frame leading to eight altered amino acids followed by a premature termination codon. Analysis of the corresponding genomic DNA fragments showed three mutations in the exon i-intron i boundary region of the GP IIIa gene. One of these mutations is a G-->T transition that eliminates the GT splice donor site in the wild type. This base pair change creates a restriction site for the enzyme Mse I. Allele-specific restriction enzyme analysis (ASRA) with Mse I of amplified genomic DNA of the parents and the proposita showed that both parents (who are first cousins) are heterozygous, whereas the proposita is homozygous for the G-->T substitution.     

New hepatitis B virus mutant form in a blood donor that is undetectable in several hepatitis B surface antigen screening assays

BACKGROUND: Envelope mutant forms of hepatitis B virus (HBV), impairing HBV antibody recognition, have been reported with mutations in single or multiple sites of the hepatitis B surface antigen (HBsAg) group- specific "a" determinant. Blood donors infected with such an HBsAg mutant form of HBV may escape detection by HBsAg screening assays and therefore may affect the safety of the blood supply. CASE REPORT: A repeat blood donor became HBsAg-reactive in an enzyme immunoassay. Confirmatory testing yielded negative results for HBsAg in a radioimmunoassay and in four enzyme immunoassays used in blood donor screening. The specificity of the HBsAg reactivity in the first enzyme immunoassay was confirmed by HBsAg neutralization with antibody to HBsAg. Additional HBV confirmatory test results were positive for antibody to hepatitis B core antigen and antibody to hepatitis B e antigen; negative for antibody to HBsAg and for hepatitis B e antigen; and positive for HBV DNA. DNA sequence analysis of the "a" determinant region of HBsAg revealed amino acid substitutions from Q (Gln) to R (Arg) at codon 129 and from M (Met) to T (Thr) at codon 133. CONCLUSION: This case illustrates the presence of HBsAg mutant forms of HBV in a West European blood donor population that were undetected by several HBsAg screening assays. Adaptation of HBsAg screening is indicated to overcome deficiencies in sensitivity in detecting HBsAg mutant forms of HBV. Screening for antibody to hepatitis B core antigen or HBV DNA may also detect blood donors infected with HBsAg mutant forms of HBV     

Angular deformity of the lower extremity: evaluation with quantitative bone scintigraphy. Work in progress

A technique for quantitative analysis of growth plates in varus or valgus deformity about the knee has been developed. Computer-generated regions of interest are placed on magnification scintigraphs to divide distal femoral and proximal tibial physes into four equal segments. The ratio of counts in the medial half to counts in the lateral half was studied in 34 children (23 healthy, 11 with angular deformity). Normal ratios were 0.74-0.98 for femurs and 0.98-1.20 for tibias. An above-normal ratio correlated with the presence of valgus deformity and a below-normal ratio with varus deformity. This technique may provide a means of monitoring growth after trauma or infection.     

槲寄生化学成分的研究——Ⅵ.槲寄生新甙Ⅵ中手性碳的绝对构型测定

本文采用降解及与已知构型的化合物进行对比的方法,确定了新黄酮甙槲寄生新甙Ⅳ中酸性部分手性碳的绝对构型。     

灰毡毛忍冬化学成分研究V灰毡毛忍冬素F和G的结构测定

Lonicera macranthoides Hand. -Mazz of Caprifoliaceae is the sources of Jinyinhua, which is a well known antipyretic and antidote in traditional Chinese medicine. Chemical studies led us to isolate 11 new compounds.Further purification of a bioactive fraction from the EtOAc soluble portion yielded two new compounds named macranthoin F and G,Their structures wereelucidated as methyl 3,4-O-dicaffeoylquinate(Ⅰ)and methyl 3,5-O-dicaffeoylquinate(Ⅱ).     

Neurofibromas: location by scanning with Tc-99m DTPA. Work in progress

The accumulation of technetium-99m diethylenetriamine pentaacetic acid (Tc-99m DTPA) in benign soft-tissue neurofibromatosis tumors is reported. In a series of 16 patients with clinical stigmata of neurofibromatosis, 28 sites of abnormal soft-tissue localization of the isotope observed scintigraphically were documented to be sites of soft-tissue tumor by clinical and/or radiographic (predominantly computed tomographic) correlations. The smallest lesion detected was a 1.5-cm subcutaneous neurofibroma. Normal physiologic nonrenal distribution of the Tc-99m DTPA was established by scintigraphic imaging of a control population.     

Central nervous system lesions in pediatric patients: Gd-DTPA-enhanced MR imaging

Twenty pediatric patients, aged 2-18 years, with known or suspected masses in the brain and/or spinal cord were studied with magnetic resonance imaging at 0.6T with and without use of 0.1 mmol/kg gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). The multisection, multiecho imaging mode was utilized. Surgically proved mass lesions included astrocytoma (n = 6), medulloblastoma (n = 2), ependymoma (n = 1), craniopharyngioma (n = 1), oligodendroglioma (n = 1), germinoma (n = 1) and fibrosarcoma (n = 1). Presumptive diagnoses included astrocytoma (n = 3), arachnoid cyst (n = 1), tuberous sclerosis (n = 1), cryptic vascular malformation (n = 1), and normal (n = 1). There was dramatic enhancement in 11 of 20 patients, with improved definition of the presence and extent of lesions in six patients. No adverse effects were noted in any of the 20 patients. It is concluded that Gd-DTPA is useful in delineating the presence, extent, and number of certain lesions of the central nervous system in children.