Postnatal Lower Jaw Dentition in Different Phenotypes of Tabby Mice

The tabby (Ta) syndrome in mouse is homologous to human anhidrotic ectodermal dysplasia, including defective development of hair, teeth, and glands. To complete the available data on the functional dentition in the Ta mice, we analyzed the mandibular cheek teeth in 261 postnatal specimens arranged in several phenotype/genotype groups: 51 Ta -hemizygous males, 56 Ta -homo/hemizygous females, 64 Ta -heterozygous females, and 40 and 50 wild-type control males and females, respectively. We evaluated tooth number, size, shape and eruption and compared these parameters in the different groups. In any individual group of Ta mice, there was variability mainly in the size and shape of the most mesial tooth and in the tooth patterns. The incidence of a reduction in tooth number in homozygous and hemizygous mice was dependent on the breeding scheme.     

Breeding ecology of visceral leishmaniasis vector sandfly in Bihar state of India

Soil samples weighing 255.3 kg, collected from 50 villages of 5 visceral leishmaniasis (VL) endemic districts of Bihar state were examined for sandfly breeding, using the soil incubation method. Breeding of sandflies was detected in 46% of the villages and 7.3% of the soil samples examined. Intra-domestic soil was found to be infested with 2 species of sandflies, Phlebotomus argentipes Annandale and Brunetti and Phlebotomus papatasi (Scopoli). In comparison with human houses, P. argentipes was found to show greater propensity to breed in cattle sheds; breeding prevalences in villages and soil samples, for the species, were significantly higher in cattle sheds than in human houses. The preference for breeding sites by the sandflies appeared to be associated with the pH of the soil. P. argentipes thus preferred to breed in the alkaline soil of cattle shed, and P. papatasi in the soil with neutral pH, of human houses. The emergence of adult P. argentipes from soil samples was mainly observed from April to October.     

福建北部地区斯氏并殖吸虫疫源地宿主感染情况分析

目的考察福建北部地区斯氏并殖吸虫中间宿主螺、蟹种群及其孳生地,比较生态环境改变前后感染率,并分析其变化原因。方法 2009-2019年,以并殖吸虫病例为线索,对福建省北部南平市的建瓯市小桥镇涤上村、东峰镇桂林村、城关镇七里街村和建阳区崇雒乡上洋村、政和县东平镇西表村、岭腰乡前溪村以及三明市的三元区居阳村等11处调查点进行现场采集螺、蟹,并考察其生态环境,设框(33 mm2)检测螺分布密度,计算螺的并殖吸虫尾蚴感染率和蟹的并殖吸虫囊蚴感染率、感染度。囊蚴采用人工感染健康犬(2只)和PCR扩增内转录间隔区2 (ITS2)序列、线粒体细胞色素氧化酶1 (CO1)基因进行鉴定。考察原孳生地生态环境的变化,复查螺、蟹的感染率、感染度,分析环境变化对感染率的影响。结果 11处调查点查见唐氏拟小豆螺、建瓯拟小豆螺和小桥拟钉螺等3种螺。山涧水源小沟或渗水湿地等微型生态环境为螺的适宜孳生地,螺多栖息于沟内水线上下5 mm的潮湿环境,主要附着于沟内潮湿的陈旧落叶、枯枝,其次为石块上,泥砂中较少。唐氏拟小豆螺、建瓯拟小豆螺和小桥拟钉螺的平均分布密度分别为156/框、179~291/框和12~266/框;各调查点均有螺查出斯氏并殖吸虫尾蚴,唐氏拟小豆螺、建瓯拟小豆螺和小桥拟钉螺的感染率分别为0.22%(4/1 851)、0.38%(36/9 420)、1.10%(102/9 247)。11处调查点查见福建华溪蟹、福建博特溪蟹、角肢华南溪蟹和待定种华南溪蟹等4种溪蟹。溪蟹多栖息于水流缓慢的山涧,白天潜伏于石块下,夜间四出觅食。溪蟹的斯氏并殖吸虫囊蚴感染率为38.99%~96.77%,平均感染率为80.21%(231/288),平均感染度为19.8个囊蚴/蟹。PCR结果显示,囊蚴样品扩增出的ITS2序列约500 bp,与GenBank中斯氏并殖吸虫相似性为99%;CO1基因序列约450 bp,与GenBank中宫崎并殖吸虫相似性为100%。人工感染实验结果显示,2只感染犬解剖后分别获得6和8条成虫,经鉴定均为斯氏并殖吸虫。孳生地环境改变有山洪暴发、垦植、干旱和人为破坏等原因,孳生地环境改变后对11处19次复查中,有10次未采集到螺,有5次未采集到蟹。5个调查点孳生地环境变化为山洪暴发所致,灾后进行7次调查均未查见螺,其中3处未查见溪蟹。11处调查点孳生地环境改变后,蟹的斯氏并殖吸虫囊蚴感染率为36.11%(91/252),平均感染度为4.9个囊蚴/蟹。孳生地环境改变前后的感染率差异具统计学意义(P<0.05)。结论福建北部建瓯等地为斯氏并殖吸虫高度感染的自然疫源地。孳生地生态环境改变后螺、蟹斯氏并殖吸虫尾蚴/囊蚴感染率下降明显,其中山洪暴发和垦植等是影响螺、蟹感染率下降的主要因素。     

3D model of frequency representation in the cochlear nucleus of the CBA/J mouse

The relationship between structure and function is an invaluable context with which to explore biological mechanisms of normal and dysfunctional hearing. The systematic and topographic representation of frequency originates at the cochlea, and is retained throughout much of the central auditory system. The cochlear nucleus (CN), which initiates all ascending auditory pathways, represents an essential link for understanding frequency organization. A model of the CN that maps frequency representation in 3D would facilitate investigations of possible frequency specializations and pathologic changes that disturb frequency organization. Toward this goal, we reconstructed in 3D the trajectories of labeled auditory nerve (AN) fibers following multiunit recordings and dye injections in the anteroventral CN of the CBA/J mouse. We observed that each injection produced a continuous sheet of labeled AN fibers. Individual cases were normalized to a template using 3D alignment procedures that revealed a systematic and tonotopic arrangement of AN fibers in each subdivision with a clear indication of isofrequency laminae. The combined dataset was used to mathematically derive a 3D quantitative map of frequency organization throughout the entire volume of the CN. This model, available online ( http://3D.ryugolab.com/ ), can serve as a tool for quantitatively testing hypotheses concerning frequency and location in the CN. J. Comp. Neurol. 521:1510–1532, 2013. © 2012 Wiley Periodicals, Inc.     

Untangling Views of Self in Interpersonal and Relational Theories

The author traces the development of ideas of self through the early and later intepersonalists and then in the work of relational theorists. She describes her own effort to explore subjective “dwelling places of self-experience,” a view that potentially overrides the intrapsychic-interpersonal dichotomy. The “political” implications of theoretical divergence between the interpersonalists and relationalists are examined with an eye toward transcending them. Recommendations are offered for future efforts to theorize the nature of self.     

Rats classified as low or high cocaine locomotor responders: A unique model involving striatal dopamine transporters that predicts cocaine addiction-like behaviors

Individual differences are a hallmark of drug addiction. Here, we describe a rat model based on differential initial responsiveness to low dose cocaine. Despite similar brain cocaine levels, individual outbred Sprague-Dawley rats exhibit markedly different magnitudes of acute cocaine-induced locomotor activity and, thereby, can be classified as low or high cocaine responders (LCRs or HCRs). LCRs and HCRs differ in drug-induced, but not novelty-associated, hyperactivity. LCRs have higher basal numbers of striatal dopamine transporters (DATs) than HCRs and exhibit marginal cocaine inhibition of in vivo DAT activity and cocaine-induced increases in extracellular DA. Importantly, lower initial cocaine response predicts greater locomotor sensitization, conditioned place preference and greater motivation to self-administer cocaine following low dose acquisition. Further, outbred Long-Evans rats classified as LCRs, versus HCRs, are more sensitive to cocaine's discriminative stimulus effects. Overall, results to date with the LCR/HCR model underscore the contribution of striatal DATs to individual differences in initial cocaine responsiveness and the value of assessing the influence of initial drug response on subsequent expression of addiction-like behaviors.     

Spatial scale and place field stability in a grid‐to‐place cell model of the dorsoventral axis of the hippocampus

The rodent hippocampus and entorhinal cortex contain spatially modulated cells that serve as the basis for spatial coding. Both medial entorhinal grid cells and hippocampal place cells have been shown to encode spatial information across multiple spatial scales that increase along the dorsoventral axis of these structures. Place cells near the dorsal pole possess small, stable, and spatially selective firing fields, while ventral cells have larger, less stable, and less spatially selective firing fields. One possible explanation for these dorsoventral changes in place field properties is that they arise as a result of similar dorsoventral differences in the properties of the grid cell inputs to place cells. Here, we test the alternative hypothesis that dorsoventral place field differences are due to higher amounts of nonspatial inputs to ventral hippocampal cells. We use a computational model of the entorhinal‐hippocampal network to assess the relative contributions of grid scale and nonspatial inputs in determining place field size and stability. In addition, we assess the consequences of grid node firing rate heterogeneity on place field stability. Our results suggest that dorsoventral differences in place cell properties can be better explained by changes in the amount of nonspatial inputs, rather than by changes in the scale of grid cell inputs, and that grid node heterogeneity may have important functional consequences. The observed gradient in field size may reflect a shift from processing primarily spatial information in the dorsal hippocampus to processing more nonspatial, contextual, and emotional information near the ventral hippocampus. © 2013 Wiley Periodicals, Inc.     

Specific blockade of morphine- and cocaine-induced reinforcing effects in conditioned place preference by nitrous oxide in mice

Nitrous oxide (N(2)O), a pharmacological active gas and an antagonist of N-methyl-D-aspartic acid receptors, has been reported to be effective in the treatment of alcohol and tobacco withdrawal syndrome. However, the neurobiological bases of N(2)O effects are unknown. The aim of the present studies was to examine the effect of N(2)O on acquisition and expression of morphine- (10 mg/kg; s.c.) and cocaine- (20 mg/kg; i.p.) induced conditioned place preference (CPP) in mice. Unbiased place conditioning method was used. Mice were exposed to N(2)O during the conditioning phase (acquisition of CPP) or during postconditioning phase (expression of CPP). The same protocol was used to evaluate the impact of N(2)O on locomotor activity, two-trial recognition task (memory), spontaneous alternation, sucrose consumption (anhedonic state), forced swim (depressive state) and elevated O-maze tests (anxiety state). In all these tests, mice were treated with morphine (10 mg/kg, s.c.) the first day, the following day mice were given saline. This sequence alternated during the next 4 days. Control animals received saline every day. The behavior of animals was evaluated on day 8. N(2)O did not induce CPP but impaired the acquisition of morphine-induced CPP and blocked the expression of cocaine- and morphine-induced CPP. The effects of the gas were long lasting and persist 4 days following the exposure. Moreover no behavioral modifications in tests usually used to investigated emotional state as compared with control mice were observed in animals exposed to N(2)O, ruling out an effect of this gas on attention, anxiety, depression, locomotion and anhedonia. These studies raise the possibility that N(2)O could have a clinical benefit in the management of morphine and cocaine addiction.     

Epinephrine-induced enhancement of memory retrieval for inhibitory avoidance conditioning in preweanling Sprague-Dawley rats

Developmental research on memory is commonly conducted using preweanling rats, but the extent to which these animals are susceptible to hormone-induced memory retrieval is unclear. This study examined the effects of epinephrine (.001, .01, or .1 mg/kg) on retrieval of IA conditioning in 17-day-old infants. Animals tested 24 hr following training performed significantly worse than infants tested 5 min after training and adults tested 24 hr later, indicating that infantile amnesia had occurred. Epinephrine attenuated this deficit in a dose-dependent manner, with a significant improvement in performance at doses of .01 mg/kg for latency and at .01 and .1 mg/kg for safe side-dependent measures. The role of epinephrine as a memory modulator is discussed in terms of its neurobiological and internal contextual effects.