DiceCT Analysis of the Extreme Gouging Adaptations Within the Masticatory Apparatus of the Aye-Aye (Daubentonia madagascariensis)

Relative to all other primates, the aye-aye (Daubentonia madagascariensis) exists at the extremes of both morphology and behavior. Its specialized anatomy—which includes hypselodont incisors and highly derived manual digits—reflects a dietary niche, unique among primates, which combines tap-foraging with gouging to locate and extract wood-boring larvae. Here, we explore the impact of this extreme dietary ecology upon the masticatory musculature of this taxon with reference to a second, similarly sized but highly generalist lemuriform—the mongoose lemur (Eulemur mongoz). Using non-destructive, high-resolution diffusible iodine-based contrast-enhanced computed tomography techniques, we reconstruct the three-dimensional volumes of eight masticatory muscles, and, for the first time in strepsirrhines, isolate and visualize their constituent muscle fascicles in situ and in three dimensions. Using these data, we report muscle volumes, forces, and fascicle lengths from each muscle portion, as well as their orientation relative to two standardized anatomical planes. Our findings demonstrate the overbuilt nature of the aye-aye's masticatory apparatus, in which each muscle possesses an absolutely and relatively larger muscle volume and PCSA than its counterpart in the mongoose lemur. Likewise, for several adductor muscles, aye-ayes also possess relatively greater fascicle lengths. Finally, we note several unusual features within the lateral pterygoid of the aye-aye—the muscle most responsible for jaw protrusion—that relate to force maximization and reorientation. As this jaw motion is critical to gouging, we interpret these differences to reflect highly specific specializations that facilitate the aye-aye's extreme subsistence strategy. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:282–294, 2020. © 2019 American Association for Anatomy     

Architectonic features and relative locations of primary sensory and related areas of neocortex in mouse lemurs

Mouse lemurs are the smallest of the living primates, and are members of the understudied radiation of strepsirrhine lemurs of Madagascar. They are thought to closely resemble the ancestral primates that gave rise to present day primates. Here we have used multiple histological and immunochemical methods to identify and characterize sensory areas of neocortex in four brains of adult lemurs obtained from a licensed breeding colony. We describe the laminar features for the primary visual area (V1), the secondary visual area (V2), the middle temporal visual area (MT) and area prostriata, somatosensory areas S1(3b), 3a, and area 1, the primary motor cortex (M1), and the primary auditory cortex (A1). V1 has “blobs” with “nonblob” surrounds, providing further evidence that this type of modular organization might have evolved early in the primate lineage to be retained in all extant primates. The laminar organization of V1 further supports the view that sublayers of layer 3 of primates have been commonly misidentified as sublayers of layer 4. S1 (area 3b) is proportionately wider than the elongated area observed in anthropoid primates, and has disruptions that may distinguish representations of the hand, face, teeth, and tongue. Primary auditory cortex is located in the upper temporal cortex and may include a rostral area, R, in addition to A1. The resulting architectonic maps of cortical areas in mouse lemurs can usefully guide future studies of cortical connectivity and function.     

恒河猴肝移植急性排斥反应中核因子κB p65的表达

背景：核因子κB作为一种重要的核内转录因子,是多种信号转导途径的汇聚点,参与机体免疫细胞的增殖、分化及细胞凋亡等多种反应物质基因的表达调控,在体液和细胞免疫中发挥重要作用。 目的：探讨恒河猴移植肝组织内核因子κB P65蛋白表达与急性排斥反应的关系。 方法：将恒河猴随机分为2组：急性排斥反应组肝移植后不给予抗排斥处理,对照组肝移植过程中及移植后均给予抗排斥处理。分别在移植后6,12,24和72 h 4个时间点收集血标本,全自动生化分析仪测定丙氨酸氨基转移酶、总胆红素,取移植肝脏组织行苏木精-伊红染色观察组织形态结构和排斥反应,根据Banff评分系统判断排斥反应程度,采用Western blot法检测肝脏组织中核因子κB p65的表达。 结果与结论：肝移植急性排斥反应发生时肝功能变化滞后于肝组织病理学检查。当急性排斥反应发生时,移植肝组织中核因子κB p65表达上调,急性排斥反应程度也随之加剧。并且在急性排斥反应早期,肝功能、病理学仅有轻微改变时,核因子κB p65表达显著升高。因此移植肝组织中核因子κB p65表达水平的检测对移植后急性排斥反应的早期诊断有重要意义,同时核因子κB可能成为控制移植急性排斥反应的新靶点。     

Volumetric Analysis of the African Elephant Ventricular System

This study used magnetic resonance imaging (MRI) to determine the volume of the ventricular system in the brain of three adult male African elephants (Loxodonta africana). The ventricular system of the elephant has a volume of ～240 mL, an order of magnitude larger than that seen in the adult human. Despite this large size, allometric analysis indicates that the volume of the ventricles in the elephant is what one would expect for a mammal with an ～5 kg brain. Interestingly, our comparison with other mammals revealed that primates appear to have small relative ventricular volumes, and that megachiropterans and microchiropterans follow different scaling rules when comparing ventricular volume to brain mass indicating separate phylogenetic histories. The current study provides context for one aspect of the elephant brain in the broader picture of mammalian brain evolution. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.     

Prevalence of antibodies and cell mediated immune response against Leishmania major in feral nonhuman primates from Kenya

In Kenya, Leishmania major is responsible for human cutaneous leishmaniasis (CL). Natural infection with L. major of a vervet monkey and experimental susceptibility of some nonhuman primates (NHPs) from Kenya has been established. However, there has been no comprehensive study of the prevalence of zoonotic CL in Kenya. And also, no investigation has been done to assess whether NHPs could be potential reservoir hosts of L. major even when the involvement of reservoir animals is obligatory in transmission of this parasite. To achieve this, wild caught Chlorocebus aethiops (Vervet monkeys n = 213), Papio cynocephalus anubis (olive baboons n = 101) and Cercopithecus mitis (Syke's monkeys n = 64) from five geographical locations in Kenya were screened for antibodies against L. major using enzyme linked immunosorbent assay (ELISA) and Western blot (WB) analysis. From the population of C. aethiops (n = 213) captured, 57 were used in lymphocyte proliferation assay. ELISA revealed a high prevalence of leishmaniasis sero conversion in olive baboons 78/101 (77.2%), vervet monkeys 129/213 (60.6%) and Sykes’ monkeys 43/64 (67.2%). WB detected anti-L. major antibodies in 48.5% (49/101) of the baboons, 48% (102/213) of vervet monkeys and 37.5% (24/64) of Sykes’ monkey sera. Specific proliferation of peripheral blood mononuclear cells to L. major antigen was demonstrated in 17 of the 57 (29.8%) vervet monkeys. In conclusion, the results of serological assays provide strong circumstantial evidence that CL is prevalent in five Provinces of Kenya and that Kenyan NHPs could be could be a potential reservoir hosts of L. major.     

Chondroitinase ABC promotes selective reactivation of somatosensory cortex in squirrel monkeys after a cervical dorsal column lesion

After large but incomplete lesions of ascending dorsal column afferents in the cervical spinal cord, the hand representation in the contralateral primary somatosensory cortex (area 3b) of monkeys is largely or completely unresponsive to touch on the hand. However, after weeks of spontaneous recovery, considerable reactivation of the hand territory in area 3b can occur. Because the reactivation process likely depends on the sprouting of remaining axons from the hand in the cuneate nucleus of the lower brainstem, we sought to influence cortical reactivation by treating the cuneate nucleus with an enzyme, chondroitinase ABC, that digests perineuronal nets, promoting axon sprouting. Dorsal column lesions were placed at a spinal cord level (C5/C6) that allowed a portion of ascending afferents from digit 1 to survive in squirrel monkeys. After 11-12 wk of recovery, the contralateral forelimb cortex was reactivated by stimulating digit 1 more extensively in treated monkeys than in control monkeys. The results are consistent with the proposal that the treatment enhances the sprouting of digit 1 afferents in the cuneate nucleus and that this sprouting allowed these preserved inputs to activate cortex more effectively.