Characterization of deletions at 9p affecting the candidate regions for sex reversal and deletion 9p syndrome by MLPA

The distal region on the short arm of chromosome 9 is of special interest for scientists interested in sex development as well as in the clinical phenotype of patients with the 9p deletion syndrome, characterized by mental retardation, trigonocephaly and other dysmorphic features. Specific genes responsible for different aspects of the phenotype have not been identified. Distal 9p deletions have also been reported in patients with 46,XY sex reversal, with or without 9p deletion syndrome. Within this region the strongest candidates for the gonadal dysgenesis phenotype are the DMRT genes; however, the genetic mechanism is not clear yet. Multiple ligation-dependent probe amplification represents a useful technique to evaluate submicroscopic interstitial or distal deletions that would help the definition of the minimal sex reversal region on 9p and could lead to the identification of gene(s) responsible of the 46,XY gonadal disorders of sex development (DSD). We designed a synthetic probe set that targets genes within the 9p23-9p24.3 region and analyzed a group of XY patients with impaired gonadal development. We characterized a deletion distal to the DMRT genes in a patient with isolated 46,XY gonadal DSD and narrowed down the breakpoint in a patient with a 46,XY del(9)(p23) karyotype with gonadal DSD and mild symptoms of 9p deletion syndrome. The results are compared with other patients described in the literature, and new aspects of sex reversal and the 9p deletion syndrome candidate regions are discussed.     

Orbitofrontal inactivation impairs reversal of Pavlovian learning by interfering with ‘disinhibition’ of responding for previously unrewarded cues

Orbitofrontal cortex (OFC) is critical for reversal learning. Reversal deficits are typically demonstrated in complex settings that combine Pavlovian and instrumental learning. Yet recent work has implicated the OFC specifically in behaviors guided by cues and the features of the specific outcomes they predict. To test whether the OFC is important for reversing such Pavlovian associations in the absence of confounding instrumental requirements, we trained rats on a simple Pavlovian task in which two auditory cues were presented, one paired with a food pellet reward and the other presented without reward. After learning, we reversed the cue–outcome associations. For half the rats, OFC was inactivated prior to each reversal session. Inactivation of OFC impaired the ability of the rats to reverse conditioned responding. This deficit reflected the inability of inactivated rats to develop normal responding for the previously unrewarded cue; inactivation of OFC had no impact on the ability of the rats to inhibit responding to the previously rewarded cue. These data show that OFC is critical to reversal of Pavlovian responding, and that the role of OFC in this behavior cannot be explained as a simple deficit in response inhibition. Furthermore, the contrast between the normal inhibition of responding, reported here, and impaired inhibition of responding during Pavlovian over‐expectation, reported previously, suggests the novel hypothesis that OFC may be particularly critical for learning (or behavior) when it requires the subject to generate predictions about outcomes by bringing together or integrating disparate pieces of associative information.     

Impulsive choice in hippocampal but not orbitofrontal cortex-lesioned rats on a nonspatial decision-making maze task

Orbitofrontal cortical (OFC) and hippocampal (HPC) lesions in primates and rodents have been associated with impulsive behaviour. We showed previously that OFC- or HPC-lesioned rats chose the immediate low-reward (LR) option in preference to the delayed high-reward (HR) option, where LR and HR were associated with different spatial responses in a uniform grey T-maze. We now report that on a novel nonspatial T-maze task in which the HR and LR options are associated with patterned goal arms (black-and-white stripes vs. gray), OFC-lesioned rats did not show impulsive behaviour, choosing the delayed HR option, and were indistinguishable from controls. In contrast, HPC-lesioned rats exhibited impulsive choice in the nonspatial decision-making task, although they chose the HR option on the majority of trials when there was a 10-s delay associated with both goal arms. The previously reported impairment in OFC-lesioned rats on the spatial version of the intertemporal choice task is unlikely to reflect a general problem with spatial learning, because OFC lesions were without effect on acquisition of the standard reference memory water-maze task and spatial working memory performance (nonmatching-to-place) on the T-maze. The differential effect of OFC lesions on the two versions of the intertemporal choice task may be explained instead in terms of the putative role of OFC in using associative information to represent expected outcomes and generate predictions. The impulsivity in HPC-lesioned rats may reflect impaired temporal information processing, and emphasizes a role for the hippocampus beyond the spatial domain.     

A comparative neuropsychological test battery differentiates cognitive signatures of Fragile X and Down syndrome

Background Standardised neuropsychological and cognitive measures present some limitations in their applicability and generalisability to individuals with intellectual disability (ID). Alternative approaches to defining the cognitive signatures of various forms of ID are needed to advance our understanding of the profiles of strengths and weaknesses as well as the affected brain areas. Aim To evaluate the utility and feasibility of six non‐verbal comparative neuropsychological (CN) tasks administered in a modified version of the Wisconsin General Test Apparatus (WGTA) to confirm and extend our knowledge of unique cognitive signatures of Fragile X syndrome (FXS) and Down syndrome (DS). Method A test battery of CN tasks adapted from the animal literature was administered in a modified WGTA. Tasks were selected that have established or emerging brain–behaviour relationships in the domains of visual‐perceptual, visual‐spatial, working memory and inhibition. Results Despite the fact that these tasks revealed cognitive signatures for the two ID groups, only some hypotheses were supported. Results suggest that whereas individuals with DS were relatively impaired on visual‐perceptual and visual‐spatial reversal learning tasks they showed strengths in egocentric spatial learning and object discrimination tasks. Individuals with FXS were relatively impaired on object discrimination learning and reversal tasks, which was attributable to side preferences. In contrast, these same individuals exhibited strengths in egocentric spatial learning and reversal tasks as well as on an object recognition memory task. Both ID groups demonstrated relatively poor performance for a visual‐spatial working memory task. Conclusion Performance on the modified WGTA tasks differentiated cognitive signatures between two of the most common forms of ID. Results are discussed in the context of the literature on the cognitive and neurobiological features of FXS and DS.     

甲羟孕酮对人卵巢癌顺铂耐药细胞株SKOV3/DDP耐药的逆转作用

目的:应用甲羟孕酮(Medroxyprogesterone Acetate,MPA)体外逆转人卵巢癌顺铂耐药细胞株SKOV3/DDP的耐顺铂(cisplatin,DDP)效应,并对其作用机制进行初步探讨。方法:采用四甲基偶氮唑蓝(MTT)法检测MPA对SKOV3/DDP的细胞毒作用,确定MPA对此细胞株的非细胞毒性剂量作为逆转剂量,同法测定非细胞毒性剂量MPA联合DDP作用后SKOV3/DDP对顺铂耐药性的变化,采用流式细胞技术(FCM)检测细胞周期及凋亡情况。结果:单用MPA浓度大于7.50 g/L时对SKOV3/DDP细胞有不同程度的抑制作用,且呈剂量依赖性。MPA浓度小于15.85 g/L时,其对细胞生长无明显抑制作用(细胞存活率均>90%),因此选用15.00 g/L作为逆转剂量。DDP联合15.00 g/L的MPA作用24、48、72 h后,顺铂的IC50分别下降至(57.72±0.48)g/L、(13.39±0.21)g/L、(7.93±0.18)g/L,逆转倍数分别为1.22,1.90,2.44倍。DDP与MPA联合作用于SKOV3/DDP细胞,使其细胞周期阻滞于G0/G1期,S期细胞比例下降,并可以增加耐药细胞的凋亡率。结论:MPA可以逆转DDP引发的卵巢癌耐药,其可能的逆转耐药机制为促进细胞的凋亡,阻滞细胞周期进程。     

Bisphenol A induces a shift in sex differentiation gene expression with testis-ova or sex reversal in Japanese medaka (Oryzias latipes)

Bisphenol A (BPA), a very important raw material in the plastics industry, is an endocrine-disrupting chemical in teleost fish. Although BPA induces testis-ova and sex reversal in teleost fish species, the molecular mechanism remains unclear. We evaluated the effects of BPA (measured concentrations: 45, 92, 326, 1030 and 3406 μg/L) on Japanese medaka (Oryzias latipes) using OECD TG234 (2011, Fish Sexual Development Test, OECD Guidelines for the Testing of Chemicals, Section 2). BPA at 1030 and 3406 μg/L induced testis-ova and sex reversal with female-type secondary sexual characteristics in XY males at 30 and 60 days posthatching (dph). Then we examined the BPA effect on the expression of sex differentiation genes related to the testis-ova and sex reversal in XY medaka. BPA exposure (1030 and 3406 μg/L) suppressed gsdf mRNA expression and increased cyp19a1a mRNA expression in XY individuals at stage 38 and 30 dph, although foxl2 mRNA expression showed no change. Interestingly, the concentration of BPA that suppressed gsdf mRNA expression at the larval stage was consistent with that needed to induce testis-ova and sex reversal. These results suggest that the gsdf gene at the embryonic stage can be used as a useful biomarker for predicting the impact of estrogenic endocrine-disrupting chemicals on sexual differentiation in Japanese medaka.     

2例SRY阳性的46,XX男性综合征细胞和分子遗传学分析

目的通过对2例社会性别为男性的不育患者的细胞及分子遗传学分析,探讨性分化异常的机制,并分析染色体核型和SRY基因检测在性发育异常中的意义。方法外周血淋巴细胞染色体核型分析;提取外周血基因组DNA,进行SRY基因、Y染色体AZF区域微缺失检测。结果 2例患者染色体核型均为46,XX,Y染色体AZF区域微缺失检测提示AZFa、b、c区全部缺失,但SRY基因均存在。结论 SRY基因是参与性别决定和分化的关键基因,对其进行检测有利于明确性反转综合征的临床诊断,通过染色体核型分析结合分子遗传学检测,可为性发育异常患者的临床确诊和治疗提供依据。