Prolonged Attenuation of the Reinforcing Strength of Cocaine by Chronic d-Amphetamine in Rhesus Monkeys

Chronic treatment with the indirect dopamine agonist d-amphetamine can reduce cocaine use in clinical trials and, in preclinical studies in laboratory animals, attenuates daily cocaine self-administration. The present study extended previous results to conditions designed to reflect a more clinically relevant experience of cocaine exposure and d-amphetamine treatment. Each morning, monkeys pressed a lever to receive food pellets under a 50-response fixed-ratio schedule of reinforcement. After determining a dose-response curve for cocaine (0.003–0.56 mg/kg per injection, i.v.) under a progressive-ratio (PR) schedule of reinforcement in the evening, cocaine self-administration sessions were suspended and d-amphetamine (0.01–0.056 mg/kg/h, i.v.) was administered continuously for at least 24 days, except during cocaine self-administration sessions, which were conducted using the PR schedule once every 8 days. When a persistent decrease in self-administration was observed, the cocaine dose-effect curve was redetermined. Cocaine- and food-maintained responding were also examined after discontinuation of d-amphetamine. Although individual differences in sensitivity were observed, d-amphetamine produced selective, qualitatively similar decreases in the reinforcing strength of cocaine in all monkeys that persisted at least 4 weeks. Moreover, cocaine dose-effect curves were shifted downward and/or to the right. For 2 weeks following discontinuation of d-amphetamine treatment, the reinforcing strength of cocaine varied within and across individuals, however, on the whole no increased sensitivity was apparent. These data provide further support for the use of agonist medications for cocaine abuse, and extend the conditions under which such treatment is successful to those that incorporate clinically relevant patterns of cocaine use and drug treatment.     

Pre-clinical evaluation of a 15-valent pneumococcal conjugate vaccine (PCV15-CRM197) in an infant-rhesus monkey immunogenicity model

The incidence of invasive pneumococcal disease (IPD), caused by the approximately 91 serotypes of Streptococcus pneumoniae (PN), varies geographically and temporally as a result of changing epidemiology and vaccination patterns as well as due to regional measurement differences. Prevnar^® (Pfizer), the first licensed pneumococcal conjugate vaccine (PCV), comprises polysaccharides (PS) from 7 serotypes conjugated to the mutant diphtheria toxin carrier protein, CRM197. In the United States and elsewhere, this vaccine has been highly efficacious in reducing the incidence of IPD caused by vaccine serotypes, however, the incidence of non-vaccine serotypes (e.g., 19A, 22F, and 33F) has increased, resulting in the need for vaccines with higher valencies. In response, 10- and 13-valent PCVs have recently been licensed. To further increase serotype coverage, we have developed a 15-valent PCV containing PS from serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 22F, 23F and 33F conjugated to CRM197 and formulated on aluminum phosphate adjuvant. Vaccine immunogenicity was evaluated in infant rhesus monkeys since they, like human infants, respond poorly to unconjugated PN PS. Infant (2-3 month old) rhesus monkeys were vaccinated three times with PCV-15 or Prevnar^® at 2 month intervals, and serotype-specific IgG antibodies were measured using a multiarray electrochemiluminescence (ECL) assay. The results indicate that antibody responses to PCV-15 and Prevnar^® were comparable for the 7 common serotypes and that post-vaccination responses to PCV-15 were >10-fold higher than baseline for the 8 additional serotypes.     

A protein-based pneumococcal vaccine protects rhesus macaques from pneumonia after experimental infection with Streptococcus pneumoniae

Infections caused by Streptococcus pneumoniae are a major cause of mortality throughout the world. Protein-based pneumococcal vaccines are envisaged to replace or complement the current polysaccharide-based vaccines. In this context, detoxified pneumolysin (dPly) and pneumococcal histidine triad protein D (PhtD) are two potential candidates for incorporation into pneumococcal vaccines. In this study, the protective efficacy of a PhtD-dPly vaccine was evaluated in a rhesus macaque (Macaca mulatta) model of pneumonia. The animals were immunized twice with 10 μg of PhtD and 10 μg of dPly formulated in the Adjuvant System AS02 or with AS02 alone, before they were challenged with a 19F pneumococcal strain. The survival was significantly higher in the protein-vaccinated group and seemed to be linked to the capacity to greatly reduce bacterial load within the first week post-challenge. Vaccination elicited high concentrations of anti-PhtD and anti-Ply antibodies and a link was found between survival and antibody levels. In conclusion, AS02-adjuvanted PhtD-dPly vaccine protects against S. pneumoniae-induced pneumonia. It is probable that the protection is at least partially mediated by PhtD- and Ply-specific antibodies.     

运动再学习对猴脑缺血损伤后脑血流量的影响

目的:观察运动再学习疗法对脑缺血损伤后恒河猴脑血流量的影响。方法:通过电凝法阻断恒河猴右侧大脑中动脉M1段制备成脑缺血损伤模型,术后采用觉醒意识水平肌力训练、协调能力及任务定向训练等运动再学习疗法(MRP),单光子发射计算机体层摄影(SPECT)测定训练前后相关脑区脑血流量的变化。结果:MRP明显改善脑缺血损伤恒河猴的局部脑血流量,但不能改变脑缺血所致的右/左脑区脑血流量的不对称性。结论:MRP可以增加脑缺血损伤周围及相关脑区脑血流量,促进受损神经功能恢复。     

GW003对恒河猴急性辐射损伤的治疗作用

目的本研究旨在观察不同剂量重组人血清白蛋白-粒细胞集落刺激因子融合蛋白（GW003）对急性放射病恒河猴的治疗作用。方法 28只成年恒河猴分为正常对照组、照射对照组及GW003 50、150和450μg/kg治疗组共5组,后4组动物（每组6只）用60Coγ射线全身双侧一次照射3.0 Gy。GW003治疗组动物分别于照射后0和7 d皮下注射GW003 50、150和450μg/kg,所有照射动物均给予对症治疗。观察照射动物一般状况、体征、外周血细胞计数、外周血和骨髓细胞集落培养及病理组织学检查结果。结果不同剂量GW003皮下注射给药能明显升高3.0 Gy照射猴外周血白细胞、中性粒细胞和造血祖细胞数,其中GW003 150和450μg/kg剂量组提高外周血白细胞、中性粒细胞、血小板和血红蛋白最低值,缩短细胞减少持续时间的作用显著,明显加速骨髓造血功能恢复,减少输血次数。结论 GW003 150μg/kg可明显促进急性辐射损伤猴造血功能恢复,对中度骨髓型急性放射病有明显的治疗作用。     

Prenatal assessment of fetal chromosomal and genetic disorders through maternal plasma DNA analysis

The existence of cell free DNA derived from the fetus in the plasma of pregnant women was first demonstrated in 1997. This discovery offered the possibility of non-invasive sampling of fetal genetic material simply through the collection of a maternal blood sample. Such cell free fetal DNA molecules in the maternal circulation have subsequently been shown to originate from the placenta and could be detected from about 7 weeks of gestation. It has been shown that cell free fetal DNA analysis could offer highly accurate assessment of fetal genotype and chromosomal makeup for some applications. Thus, cell free fetal DNA analysis has been incorporated as a part of prenatal screening programs for the prenatal management of sex-linked and sex-associated diseases, rhesus D incompatibility as well as the prenatal detection of Down's syndrome.Cell free fetal DNA analysis may lead to a change in the way prenatal assessments are made.     

Naïve and memory B cells in the rhesus macaque can be differentiated by surface expression of CD27 and have differential responses to CD40 ligation

The rhesus macaque (RM) model has the potential to be an invaluable tool for studying B cell populations during pathogenic infections, however, to date, there has been no definitive delineation of naïve and memory B cell populations in the RM. This has precluded a rigorous analysis of the generation, persistence and resolution of a pathogen-specific memory B cell response. The present study utilized multiple analyses to demonstrate that CD27 expression on B cells is consistent with a memory phenotype. Compared to CD20+CD27− B cells, CD20+CD27+ B cells were larger in size, and preferentially accumulated at effector sites. Direct sequence analysis revealed that CD20+CD27+ B cells had an increased frequency of point mutations that were consistent with somatic hypermutation and at a functional level, CD40 ligation improved CD20+CD27− but not CD20+CD27+ B cell survival in vitro. These data provide definitive evidence that the naïve and memory B cell populations of the RM can be differentiated using surface expression of CD27.     

DNA vaccination in rhesus macaques induces potent immune responses and decreases acute and chronic viremia after SIVmac251 challenge

Optimized plasmid DNAs encoding the majority of SIVmac239 proteins and delivered by electroporation (EP) elicited strong immune responses in rhesus macaques. Vaccination decreased viremia in both the acute and chronic phases of infection after challenge with pathogenic SIVmac251. Two groups of macaques were vaccinated with DNA plasmids producing different antigen forms, “native” and “modified,” inducing distinct immune responses. Both groups showed significantly lower viremia during the acute phase of infection, whereas the group immunized with the native antigens showed better protection during the chronic phase (1.7 log decrease in virus load, P = 0.009). Both groups developed strong cellular and humoral responses against the DNA vaccine antigens, which included Gag, Pol, Env, Nef, and Tat. Vaccination induced both central memory and effector memory T cells that were maintained at the day of challenge, suggesting the potential for rapid mobilization upon virus challenge. The group receiving the native antigens developed higher and more durable anti-Env antibodies, including neutralizing antibodies at the day of challenge. These results demonstrate that DNA vaccination in the absence of any heterologous boost can provide protection from high viremia comparable to any other vaccine modalities tested in this macaque model.     

Specific retinotopically based magnocellular impairment in a patient with medial visual dorsal stream damage

We report here retinotopically based magnocellular deficits in a patient with a unilateral parieto-occipital lesion. We applied convergent methodologies to study his dorsal stream processing, using psychophysics as well as structural and functional imaging. Using standard perimetry we found deficits involving the periphery of the left inferior quadrant abutting the horizontal meridian, suggesting damage of dorsal retinotopic representations beyond V1. Retinotopic damage was much more extensive when probed with frequency-doubling based contrast sensitivity measurements, which isolate processing within the magnocellular pathway: sensitivity losses now encroached on the visual central representation and did not respect the horizontal meridian, suggesting further damage to dorsal stream retinotopic areas that contain full hemi-field representations, such as human V3A or V6. Functional imaging revealed normal responses of human MT+ to motion contrast. Taken together, these findings are consistent with a recent proposal of two distinct magnocellular dorsal stream pathways: a latero-dorsal pathway passing to MT+ and concerned with the processing of coherent motion, and a medio-dorsal pathway that routes information from V3A to the human homologue of V6. Anatomical evidence was consistent with sparing of the latero-dorsal pathway in our patient, and was corroborated by his normal performance in speed, direction discrimination and motion coherence tasks with 2D and 3D objects. His pattern of dysfunction suggests damage only to the medio-dorsal pathway, an inference that is consistent with structural imaging data, which revealed a lesion encompassing the right parieto-occipital sulcus.