基于"WD倒谱"法分析人体脾组织的超声散射微结构特征

本文提出了一种对超声散射信号分析的新方法--“WD倒谱”法,并利用该方法对人体正常脾和脾增生组织的回波信号进行了分析,对软组织中散射子的平均间距进行了估计,结果表明：两种脾组织散射子的平均同距明显不同;“WD倒谱”能有效的反映软组织的微观结构特征,说明“WD倒谱”是软组织超声散射信号分析与软组织散射子平均间距定征的一种有效方法。     

Visual cortex ablation and thresholds for successively presented stimuli in rhesus monkeys: II. Hue

Summary Rhesus monkeys were trained to discriminate successively presented hues. The smallest difference they could reliably detect was determined before and after either inferotemporal ablation, or a lesion intended to remove as much as possible of prestriate area V4 (Zeki, 1973).As a group, the animals with lesions of V4 showed good but not perfect retention of their preoperative performance, and their thresholds were unaltered. The inferotemporal group showed no retention of the simplest successive task, red versus green, but after relearning their thresholds too were unaltered. It appears that animals without inferotemporal cortex can form precise internal representations of hues, and that the basis of the inferotemporal learning impairment may depend upon the nature of the stimuli to be discriminated.     

DHPLC screening of cystic fibrosis gene mutations

Denaturing high performance liquid chromatography (DHPLC) using ion-pairing reverse phase chromatography (IPRPC) columns is a technique for the screening of gene mutations. In order to evaluate the potential utility of this assay method in a clinical laboratory setting, we subjected the PCR products of 73 CF patients known to bear CFTR mutations to this analytic technique. We used thermal denaturation profile parameters specified by the MELT program tool, made available by Stanford University. Using this strategy, we determined an initial analytic sensitivity of 90.4% for any of 73 known CFTR mutations. Most of the mutations not detected by DHPLC under these conditions are alpha-substitutions. This information may eventually help to improve the MELT algorithm. Increasing column denaturation temperatures for one or two degrees above those recommended by the MELT program allowed 100% detection of CFTR mutations tested. By comparing DHPLC methodology used in this study with the recently reported study based on Wavemaker 3.4.4 software (Transgenomic, Omaha, NE) [Le Marechal et al., 2001) and with previous SSCP analysis of CFTR mutations [Ravnik-Glavac et al., 1994] we emphasized differences and similarities in order to refine the DHPLC system and discuss the relationship to the alternative approaches. We conclude that the DHPLC method, under optimized conditions, is highly accurate, rapid, and efficient in detecting mutations in the CFTR gene and may find high utility in screening individuals for CFTR mutations. Hum Mutat 19:374-383, 2002. Published 2002 Wiley-Liss, Inc.     

Long term health and neurodevelopment in children exposed to antiepileptic drugs before birth

Objective: To investigate the frequency of neonatal and later childhood morbidity in children exposed to antiepileptic drugs in utero.

Design: Retrospective population based study.

Setting: Population of the Grampian region of Scotland.

Participants: Mothers taking antiepileptic drugs in pregnancy between 1976 and 2000 were ascertained from hospital obstetric records and 149 (58% of those eligible) took part. They had 293 children whose health and neurodevelopment were assessed.

Main outcome measures: Frequencies of neonatal withdrawal, congenital malformations, childhood onset medical problems, developmental delay, and behaviour disorders.

Results: Neonatal withdrawal was seen in 20% of those exposed to antiepileptic drugs. Congenital malformations occurred in 14% of exposed pregnancies, compared with 5% of non-exposed sibs, and developmental delay in 24% of exposed children, compared with 11% of non-exposed sibs. After excluding cases with a family history of developmental delay, 19% of exposed children and 3% of non-exposed sibs had developmental delay, 31% of exposed children had either major malformations or developmental delay, 52% of exposed children had facial dysmorphism compared with 25% of those not exposed, 31% of exposed children had childhood medical problems (13% of non-exposed sibs), and 20% had behaviour disorders (5% of non-exposed).

Conclusion: Prenatal antiepileptic drug exposure in the setting of maternal epilepsy is associated with developmental delay and later childhood morbidity in addition to congenital malformation.

     

P67L: a cystic fibrosis allele with mild effects found at high frequency in the Scottish population.

Only three mutant cystic fibrosis (CF) alleles have to date been established as conferring a dominant mild effect on affected subjects who are compound heterozygotes. We now add a fourth, P67L, which occurs on about 1.4% of Scottish CF chromosomes. Among 13 patients (12 unrelated) with this allele, the average age at diagnosis was 22.5 +/- 11.3 years. None of the cases had consistently raised sweat chloride concentrations, the average value being 57 +/- 9 mmol/l; 77% of the patients were pancreatic sufficient. When compared to three other established mild CF alleles, R117H, A455E, and 3849 + 10kb C-T, a compound heterozygote for P67L has minimal disease and clinical suspicions are unlikely to be confirmed other than by DNA typing.     

Differential diagnosis of dementia and depression in the elderly using neuropsychological methods

This study examined the utility of the Halstead-Reitan Neuropsychological Battery in the differential diagnosis of dementia, major depression, and general neurological impairment. Orthogonal contrasts between groups showed superior performance for depressives on most Halstead-Reitan subtests. Contrasts between organically impaired groups showed that these groups did not differ significantly (p >.05) on any of the Halstead-Reitan subtests. A step-wise discriminant analysis indicated that on the basis of neuropsychological variables alone, demented patients were differentiated from elderly depressed with clinical levels of accuracy. However, when neurologically impaired and demented patients were considered together in a single group reflecting organic impairment, hits increased dramatically. The results were discussed in terms of their implications for differentially diagnosing dementia and depression in the elderly.     

Removal of dihydroxy-terminated components from monomethoxy-terminated poly(ethylene glycol)

A preparative method to remove dihydroxy-terminated components in a sample of presumably monomethoxy, monohydroxy-terminated poly(ethylene glycol) (PEG) is presented. Purification of the monomethoxy-terminated component allows one to prepare a diblock copolymer of PEG and poly(lactic acid) (PLLA) free of a PLLA-PEG-PLLA triblock copolymer in various biomedical applications of the copolymer. Efficiency of the purification is compared for high osmotic pressure chromatography (HOPC) and preparative size exclusion chromatography (SEC). In HOPC, various types of porous silica particles, surfaces, solvents, polymer concentrations have been screened for the optimal performance. It was found that HOPC is more efficient than SEC, especially HOPC of 30-40 wt% solutions in water by a column packed with acid-washed controlled pore glass is optimal in producing high-purity fractions.