C基因截短的HBV复制与包装

目的 探讨C基因截短型HBV变异体的复制与包装。方法 采用分子克隆、人工定点突变等技术构建C基因截短型HBV变异体质粒，用脂质体法转染HepG2细胞，提取细胞内及培养上清液中DNA分别进行Southem杂交，PCR及实时定量荧光PCR分析。结果 经DNA测序及酶切鉴定证实C基因截短型HBV质粒载体构建成功；C基因截短型HBV为复制缺损型，与辅助质粒共转染HepG2细胞，可在细胞内及培养上清液中检测到HBV各种DNA构型；DNA定量分析提示C基因截短型HBV的包装效率较野生型HBV提高3～40倍。结论 C基因截短型HBV变异体为复制缺损型，单独转染后不能在肝细胞内包装与复制，但在缺失包装信号ε的相应辅助病毒辅助下可有效复制并包装成子代病毒颗粒分泌到胞外，且包装效率大大提高。     

Miscibility and Intermolecular Specific Interactions in Blends of Poly(hydroxyether sulfone) and Poly(N‐vinylpyrrolidone)

Summary: The blends of poly(hydroxyether sulfone) (PHES) with poly(N‐vinylpyrrolidone) (PVPy) were investigated by means of differential scanning calorimetry (DSC) and FTIR spectroscopy. The miscibility of the blend system was established on the basis of the thermal analysis results. DSC showed that the PHES/PVPy blends prepared by casting from N,N‐dimethylformamide (DMF) possessed single, composition‐dependent glass transition temperatures, indicating that the blends are miscible in the entire composition. The experimental glass transition temperatures have higher values than those calculated on the basis of additive behavior; the variation of the glass transition temperatures of the blends was accounted for by the Kwei equation. FTIR studies indicate that competitive hydrogen bonding interactions exist upon addition of PVPy to the system, which were involved in the self‐ and cross‐association, i.e., ? OH···O?S, ? OH···OH of PHES and ? OH···O?C< of PVPy. The FTIR spectra in the range of the sulfonyl stretching vibrations showed that the hydroxyl‐associated sulfonyl groups are partially “set free” upon addition of PVPy to the system. The IR spectroscopic investigation of both the model compounds and the PHES/PVPy blends suggests that the strength of the hydrogen bonding interactions in the blend system increases in the following order: ? OH···O?S, ? OH···OH and ? OH···O?C<.

Plot of glass transition temperature for PHES/PVPy blends as a function of weight fraction of PVPy. The prediction of the Kwei equation yields the values of k = 1 and q = 122.     

Mutation analysis of the TSC1 and TSC2 genes in Japanese patients with pulmonary lymphangioleiomyomatosis

Pulmonary lymphangioleiomyomatosis (LAM) is a destructive lung disease characterized by a diffuse hamartomatous proliferation of smooth muscle cells (LAM cells) in the lungs. Pulmonary LAM can occur as an isolated form (sporadic LAM) or in association with tuberous sclerosis complex (TSC) (TSC-LAM), a genetic disorder with autosomal dominant inheritance with various expressivity resulting from mutations of either the TSC1 or TSC2 gene. We examined mutations of both TSC genes in 6 Japanese patients with TSC-LAM and 22 patients with sporadic LAM and identified six unique and novel mutations. TSC2 germline mutations were detected in 2 (33.3%) of 6 patients with TSC-LAM and TSC1 germline mutation in 1 (4.5%) of 22 sporadic LAM patients. In accordance with the tumor-suppressor model, loss of heterozygosity (LOH) was detected in LAM cells from 3 of 4 patients with TSC-LAM and from 4 of 8 patients with sporadic LAM. Furthermore, an identical LOH or two identical somatic mutations were demonstrated in LAM cells microdissected from several tissues, suggesting LAM cells can spread from one lesion to another. Our results from Japanese patients with LAM confirmed the current concept of pathogenesis of LAM: TSC-LAM has a germline mutation but sporadic LAM does not; sporadic LAM is a TSC2 disease with two somatic mutations; and a variety of TSC mutations causes LAM. However, our study indicates that a fraction of sporadic LAM can be a TSC1 disease; therefore, both TSC genes should be examined, even for patients with sporadic LAM. Received: August 30, 2001 / Accepted: November 2, 2001     

聚甲基丙烯酸羟乙酯水凝胶人工晶状体材料的合成与性能

以甲基丙烯酸羟乙酯为原料,过硫酸铵/偏重亚硫酸钠为引发体系,二甲基丙烯酸三乙二醇酯为交联剂,采用溶液聚合法制备了聚甲基丙烯酸羟乙酯水凝胶(PHEMA)人工晶状体材料。系统考察了聚合反应时间、温度及引发剂和交联剂的用量等对该水凝胶材料机械强度、平衡水含量(EWC)的影响,并对PHEMA水凝胶的结构和光学性能进行了表征。实验结果表明,PHEMA水凝胶的最佳合成条件为:引发剂0.5wt%,交联剂1.0wt%,反应温度40℃,反应时间36h。在此条件下制备的PHEMA水凝胶的拉伸强度达到0.57MPa,邵氏A硬度为23.0,平衡含水量超过40%,透光率≥97%。     

An Experimental Comparison of Flat-Panel Detector Performance for Direct and Indirect Systems (Initial Experiences and Physical Evaluation)

The purpose of this work was to compare direct and indirect detectors in terms of their system linearity, presampled modulation transfer function (MTF), Wiener spectrum (WS), noise equivalent quanta (NEQ), and power spectrum. Measurements were made on two flat-panel detectors, GE Revolution XR/d (indirect) and Shimadzu Safire (direct) radiographic techniques. The system linearity of the systems was measured using a time-scale method. The MTF of the systems was measured using an edge method. The WS of the systems was determined for a variable range of exposure levels by two-dimensional Fourier analysis. The NEQ was assessed from the measured MTF, WS, and estimated ideal signal-to-noise ratios. Power spectrum analyzed the chest phantom within artificial lesions. System linearity was excellent for the direct systems. For the direct system, the MTF was found to be significantly higher than that for the indirect systems. For the direct system, the WS was relatively uniform across all frequencies. In comparison, the indirect system exhibited a drop in the WS at high frequencies. At lower frequencies, the NEQ for the indirect system was noticeably higher than for the direct system. Power spectrum for the direct system was relatively flat and similar to that for white noise. The indirect system exhibited significant reduction at high spatial frequencies. In general, the direct systems exhibit improved image quality over indirect systems at comparable exposure dose.     

A female with X‐linked Nephrogenic diabetes insipidus in a family with inherited central diabetes Insipidus: Case report and review of the literature

There are two forms of diabetes insipidus, central (neurohypophyseal), and nephrogenic, caused by pathogenic variants in the AVP gene and the AVPR2 or AQP2 genes, respectively. We report on a four‐generation family, seven individuals had central diabetes insipidus (CDI) and the female index patient seen from age 16 to 26 years had (mild) nephrogenic diabetes insipidus. In her father with CDI, a known pathogenic heterozygous AVP variant c.232_234del p.(Glu78del) was identified, confirming the diagnosis of CDI in him and the other affected family members. In the proband, molecular analysis disclosed a novel heterozygous AVPR2 gene variant, c.962A > T p.(Asn321Ile) and an extremely skewed X‐inactivation, confirming X‐linked nephrogenic diabetes insipidus (XL‐NDI). Whole exome sequencing showed no further causative mutation. This is the first report on the co‐existence of CDI and NDI in one family. Our review of symptomatic female AVPR2 heterozygotes includes 23 families with at least one affected female (including this study). There were 21 different causative mutations. Mutation types in females did not differ from those in males. Both severe XL‐NDI and mild forms were reported in females. All six females with severe XL‐NDI had complete loss‐of‐function (null) mutations. The remaining 17 female probands had milder XL‐NDI caused by 14 missense variants and three null variants of the AVPR2 gene. X‐inactivation was studied in nine of these females; all showed extreme or slight skewing. The review underlines that XL‐NDI in female AVPR2 heterozygotes is always accompanied by skewed X‐inactivation, emphasizing a need for X‐inactivation studies in these females.     

The failed repressor: EEG asymmetry as a moderator of the relation between defensiveness and depressive symptoms

This study assessed the joint effects of defensiveness and frontal asymmetry in predicting symptoms of depression and anxiety. Depression symptoms were measured with the Beck Depression Inventory (BDI) and anxiety symptoms with the Taylor Manifest Anxiety Scale (TMAS). Defensiveness was assessed with both the Marlowe Crowne Social Desirability Scale (MCSD) and the Eysenck Personality Questionnaire L scale (EPQL). Participants completed two EEG recording sessions 3 weeks apart. Six baselines, three eyes open and three eyes closed, were recorded in each session. Alpha power (8–13 Hz) was computed and log transformed. R–L asymmetry was computed at eight pairs of homologous sites for aggregated data. Defensiveness (EPQL and MCSD scores) and depression symptoms (BDI) were assessed at the beginning of the first session. L and MCSD correlated positively with anterior R–L asymmetries. For both scales, the highest correlations were observed at F8–F7. L interacted with F8–F7 asymmetry to predict depressive symptoms. Among left frontally active individuals, there was trend toward a negative correlation between L and BDI. Among the right frontally active individuals, the correlation between L and the BDI was positive. MCSD did not moderate the relation between F8–F7 asymmetry and BDI. The results are consistent with the hypothesis that defensiveness protects against symptoms of depression in the context of left frontal activity, and serves as a diathesis for depression in the context of right frontal activity. High-defensive individuals who are right frontally active may represent “failed repressors,” i.e. individuals for whom defensiveness does not protect against depression, and may even exacerbate it.     

Characteristics of the delayed rectifier K current compared in myocytes isolated from the atrioventricular node and ventricle of the rabbit heart

The delayed rectifier potassium current (I _K) is known to be important in action potential repolarisation and may contribute to the diastolic pacemaker depolarisation in pacemaker cells from the heart. In this study, using whole-cell patch clamp, we investigated the characteristics of I _K in morphologically normal cells from the atrioventricular node (AVN) and ventricle of the rabbit heart. Cells were held at −40 mV and 5 μM external nifedipine was used to block L-type calcium current (I _Ca,L). Significant I _K was observed with pulses to potentials more positive than −30 mV. The steady-state activation curve in both cell types showed maximal activation at between + 10 and + 20 mV. Half-maximal activation of I _K occurred at −4.9 and −4.1 mV with slope factors of 8.3 and 12.4 mV in ventricular and AVN cells, respectively. Using pulses of increasing duration, significant I _K tails after repolarisation from + 40 mV were observed with pulses of 20 ms and increased with pulses up to 100–120 ms in both cell types. Pulses of longer duration did not activate further I _K and this suggested that only the rapid component of I _K, called I _Kr, was present in either cell type. Moreover, I _K tails after pulses to all potentials were blocked completely by E-4031, a selective blocker of I _Kr. The reversal potential of I _K varied with the concentration of external K. Superfusion of AVN cells with medium containing 4, 15 and 40 mM [K⁺]_o resulted in reversal potentials of −81, −56 and −32 mV, respectively, which are close to values predicted if the I _K channel were highly selective for K. The time constants for deactivation of I _K in ventricle and AVN on return to −40 mV after a 500-ms activating pulse to + 60 mV were 480 ms and 230 ms, respectively. The faster deactivation of I _K in AVN cells was a distinguishing feature and suggests that there may be differences in the I _Kr channel protein between ventricular and AVN cells. Received: 24 July 1995 /Received after revision: 20 October 1995 /Accepted: 23 October 1995     

SLEEP CYCLES AND SKIN POTENTIAL IN NEWBORNS STUDIED WITH A SIMPLIFIED OBSERVATION AND RECORDING SYSTEM

A simple visual observation system, supplemented by measurement of skin potential, was devised for developmental studies of sleep cycles in settings where multiple electrode placement is not practicable. The findings replicated essential features of quiet and active sleep cycles which had been reported previously to exist against the background of decreasing level of physiological arousal, as sleep proceeds. Twelve newborns showed approximately one-half of their inter-feeding sleeping time in the rapid eye movement stage of sleep. Skin potential rapidly declined from the waking level, continued to decrease in level throughout sleep, increased in variability during REM sleep, and increased in level at the second waking period.