重组HBsAg免疫逃逸突变体的表达及其抗原性分析

为了深入研究乙型肝炎病毒S基因变异所致的包膜抗原抗原性的改变，从含ＨＢＶＤＮＡ双拷贝的质粒载体ｐＥｃｏｂ６，获得一个８３７ｂｐ的ＨＢＶ－Ｓ基因片段，将其插入至载体ｐＢｌｕｅｓｃｒｉｐｔ ＫＳ~＋的ＳｍａⅠ位点，通过体外寡核苷酸介导的人工定点突变分别获得第１４５位、１２６位和第１４５位＋１２６位氨基酸三种Ｓ基因变异型。然后将这些Ｓ基因变异片段克隆到真核表达载体ｐＭＥｐ４上，从而构建了含ＨＢＶ－Ｓ基因及其突变型的表达载体ＰＭＥｐ４ＨＢＶＳＭ。用其转染人肝癌细胞系ＨｅｐＧ２，获得稳定分泌ＨＢｓＡｇ及其变异体的抗性细胞系。经体外初步研究表明，ＨＢｓＡｇ １４５位氨基酸变异体可影响ＨＢｓＡｇ的“ａ”抗原决定簇的结构。     

Persistence of nevirapine exposure during the postpartum period after intrapartum single-dose nevirapine in addition to zidovudine prophylaxis for the prevention of mother-to-child transmission of HIV-1

OBJECTIVE: To determine nevirapine (NVP) plasma levels during the postpartum period after a single intrapartum NVP dose for the prevention of mother-to-child transmission. METHODS: Plasma samples at delivery and during days 8 to 45 postpartum were obtained from HIV-infected Thai women who received an intrapartum NVP dose in the Perinatal HIV Prevention Clinical Trial-2 (PHPT-2) for the prevention of perinatal HIV transmission. These data were combined with NVP concentration data from 2 phase 1 studies of NVP for a population analysis. RESULTS: The median NVP level fell to 68 ng/mL (range: <50-228, n = 43) 8 to 14 days after dosing and to 51 ng/mL (range: <50-166, n = 25) between 15 and 21 days. During the second and third weeks postpartum, NVP levels were below the limit of quantitation in 23% and 44% of samples, respectively. Between 21 and 45 days, no sample had a quantifiable NVP concentration. A simulation derived from the population analysis predicts that NVP concentration falls to less than 10 ng/mL in 5% of women by 11 days, in 50% of women by 17.5 days, and in 95% of women by 28 days. CONCLUSIONS: Significant NVP concentrations remained for up to 20 days in these Thai women. To ensure that coverage is maintained until NVP concentrations fall to nonsuppressive levels, 1 month of additional antiretroviral treatment after delivery should be considered to prevent the emergence of resistant viruses.     

Effect of the peroxisome proliferator perfluorodecanoic acid on growth and lipid metabolism in Sprague Dawley rats fed three dietary levels of selenium

The possible interrelationships between the effects of dietary selenium and perfluorodecanoic acid (PFDA) on growth and lipid metabolism were studied in the male Sprague Dawley rat. Rats were divided into groups and placed on diets containing three levels of selenium (0.04, 0.2, and 1.0 ppm as sodium selenite). Two weeks later, half the rats in each group received a single 35 mg/kg IP injection of PFDA in corn oil, while their pair-fed companion received only vehicle. Rats injected with PFDA stopped gaining weight, and weighed less than pair-fed controls, despite equal food intakes. Two weeks following PFDA administration the rats were killed and plasma cholesterol and triglycerides, and liver peroxisomal enzyme activities were quantified. In contrast to other peroxisome proliferators, PFDA increased plasma triglycerides while decreasing plasma cholesterol. The rate of peroxisomal fatty acid -oxidation was decreased, even though the activity of fatty acyl-CoA oxidase, the first enzyme in the peroxisomal fatty acid -oxidation pathway, was increased. Dietary selenium, other than increasing the liver to body weight ratio, did not alter growth or lipid metabolism. This study demonstrates, for the first time, the existence of a non-hypotriglyceridemic peroxisome proliferator-PFDA.     

Tumoral calcinosis in infancy

The most frequent form of idiopathic calcinosis is tumoral calcinosis (TC) which rarely occurs at young ages. We describe here a TC case of a young boy with its light microscopy completed with electron microscopic examinations. X-ray microanalysis revealed in the intracellular crystals CaCl₂ besides the previously described hydroxyapatite. The significance of this finding is unknown at the moment.     

Anaesthetic management of a patient with a descending thoracic aortic aneurysm and severe bilateral bullous pulmonary parenchymal disease

The anaesthetic management of the surgical repair of a descending aortic aneurysm in a patient with large, bilateral, pulmonary bullae is described. Anaesthesia for descending aortic surgery normally involves unilateral, positive-pressure ventilation, an option which poses some risk of barotrauma in the presence of bilateral bullae. Patients with bullous disease commonly have severe lung disease and thorough preoperative assessment and preparation are necessary. Intraoperatively, bilateral rupture of the bullae could be catastrophic and preparations should be made for this possibility. In order to diminish this risk, a surgical technique including preemptive collapse of the bulla by minithoracotomy and tube drainage, with use of a bronchial blocker to the affected part of the lung may be used. If rupture occurs, then high frequency jet ventilation may be effective. Use of a double lumen endobronchial tube may be advantageous for patients with either unilateral and bilateral bullae. Anaesthesia for patients with bullae should avoid positive-pressure ventilation and nitrous oxide in order to limit the risk of barotrauma from a ball valve mechanism. In this case, the risk of barotrauma was reduced by performing an inhalational induction of anaesthesia and limiting peak inflation pressures during thoracotomy. It was elected to use positivepressure ventilation through a double lumen endobronchial tube following chest incision. A high frequency jet ventilator was available but not employed. Anaesthetic management was complicated by the presence of pleural adhesions, surgical approach directly through a bulla, and the requirement for one lung ventilation. The de i’aone descendante aecouverte cnez un pattent porde grosses bulles bilatérales d’emphysème est discutée, esthésie habituelle pour une chirurgie de l’aorte descendante site une ventilation mécanique unilatérale et constitue ainsi sque additionnel pour le porteur de bulles emphysémas bilatérales. Ces patients ont ordinairement des affections onaires graves et l’évaluation et la préparation préopéraprennent une importance spéciale. Pendant l’intervention, pture de bulles bilatérales peut être catastrophique et il se préparer à cette éventualité. Pour minimiser ce risque, technique chirurgicale qui inclut le collapsus préventif de lle par minithoracotomie et drainage, avec installation d’un ieur bronchique sur la partie atteinte du poumon. Si une re survient, le passage à la ventilation par jet à haute tence peut être salutaire. Le tube endobronchique à double ère peut présenter des avantages aussi bien dans les cas ulles unilatérales que bilatérales. Chez ces patients, il vaut x s’abstenir de ventiler avec une pression positive et du xyde d’azote afin de limiter le risque de barotraumisme soupape. Dans ce cas-ci, on a réussi à limiter le risque arotraumatisme en réalisant une induction par inhalation réduisant la pression d’inflation de pointe pendant la cotomie. Après l’incision thoracique, on a choisi d’utiliser tilation mécanique avec un tube endobronchique à double ère. Un ventilateur à jet à haute fréquence était prêt mais as été utilisé. La gestion de l’anesthésie a été compliquée par dhérences pleurales, par la rencontre d’une bulle d’emphysà l’incision et par l’obligation de ventiler un seul poumon.     

Use of self-operated auditory prompts to decrease aberrant behaviors in students with moderate mental retardation

We examined the effectiveness of self-operated auditory prompts when used to decrease the off-task and aberrant behaviors of two students with moderate mental retardation. Its purpose was to determine if self-operated auditory prompts could be effectively used by these individuals to decrease their off-task and aberrant behaviors in work settings and during transitional times between settings. A multiple-probe across settings design with a reversal and replication was used to evaluate the effectiveness of the self-operated auditory prompting system on aberrant student behaviors in school and community settings. Previous findings were replicated in this study that demonstrate that stimulus control can be achieved through the use of self-operated auditory prompts, and demonstrates that these prompts can serve to occasion a decrease in aberrant behaviors when used by individuals with moderate mental retardation in school and community settings.     

Duodenal ulcer and working-class mobility in an African population in South Africa

The number of Africans in Johannesburg presenting with duodenal ulcers has steadily increased over the past 50 years. The characteristics of 105 patients with duodenal ulcer who presented a Baragwanath Hospital were compared with those of matched and unmatched samples of patients without gastrointestinal conditions in the same hospital. Men with duodenal ulcers were found to be significantly better educated than their controls, most had been born in the town, and more of them were employed at higher, though not the highest, educational levels. These data were used to test Susser's proposition that duodenal ulcers are associated with "early urbanisation." Johannesburg blacks with duodenal ulcer did seem to fit the pattern, but the relation between stress and duodenal ulcer remains unclear.     

The effect of spikes and spike-free epochs on topographic brain maps

Maps of foci, when no discharges nor obvious slow activity were included in the map, usually (84%) showed changes within the focus itself and also in adjacent areas (58%) and often (47%) in the mirror region. An increase in activity was more often seen in the more active foci, especially in the delta and beta 2 ranges, and decrease in activity was usually seen with inactive foci. When discharges were included in the maps, an increasing number was associated with an increase at the main focus in all ranges, especially in delta and beta 1, but much less often in beta 2. The amount of electrical charge required for a change in the map with spikes was approximately 40 nanocoulombs (nC) for the first and second changes, increasing to around 50 nC with adjacent or separate foci. "Artificial" spikes produce more delta activity than other frequency ranges and the FFT of various pulses show maximal amplitudes at the slowest frequencies.