A Method for Histological Examination of Undecalcified Teeth

A method is presented for histological examination of undecalcified ground sections of tooth roots affected with periodontal disease. The roots were placed in Karnovsky's fixative overnight, postfixed in 2% buffered osmic acid, and dehydrated in an ascending series of ethanol. The specimens were then infiltrated with propylene-oxide and Epon-Araldite resin, embedded in Epon-Araldite, and sections were prepared using a cutting and grinding system. The resulting ground sections were 8-12 μm thick. The sections were allowed to air dry at room temperature. When thoroughly dried, a coverglass was applied using resinous mounting medium DPX. The specimens were examined by phase-contrast microscopy. The method is useful for simultaneous examination of mineralized dental tissue and bacterial morphotypes covering the root surface of teeth involved with periodontal disease.     

Immunocytochemistry of luteinizing hormone releasing hormone (LHRH) and gonadotropic hormones in the sheep after anterior deafferentations of the hypothalamus

Summary Using the immunoperoxidase method, the effect of the anterior deafferentations on the (1) LHRH-neuronal system in the hypothalamus and (2) gonadotropic cells in the adenohypophysis of the ewe were investigated. Two kinds of the anterior deafferentations were placed in the hypothalamus of cycling ewes. The first was performed at the level of caudal border of the chiasma opticum (CB deafferentation) and separated the medio-basal hypothalamus (MBH) from the anterior hypothalamic area (AHA). The second, was placed above the midline of the optic chiasma (MB deafferentation) and detached the AHA from the area praeoptica (AP). Estrous cycles and ovulation ceased in all CB-deafferentation. Immunocytochemical observations revealed a complete lack of LHRH-material both in the hypothalamic nuclei and in all parts of the median eminence (ME) and disappearance of LH-cells in the pituitary gland. In MB deafferented animals, only a diminished density of LHRH-material occurred in the rostral and central parts of the ME, but the ewes continued estrous cycles. Furthermore, numerous LHRH-axons and some LHRH-perikarya were visible in the regions of the AP and AHA. From these results the author is of the opinion, that in the ewe, principally AHA, but not MBH, retains the ability to produce LHRH. Difficulties in staining LHRH-perikarya suggest that in this species LHRH may be synthesized in an immunologically inactive (prohormonal) form.     

Effects of HIS1 modifications on the ability of vasoactive intestinal peptide to stimulate adenylate cyclase from rat and human tissues

The importance of the N-terminal His residue of VIP for stimulating adenylate cyclase was appreciated by estimating the intrinsic activity and EC50 of four VIP analogues on membranes from rat lung, liver, brain, anterior pituitary, and pancreas, and on human heart membranes. In all tissue preparations tested except one, the order of efficacy (and often potency) was: VIP greater than (Ac-His1)VIP greater than (Phe1)VIP = (3-Me-His1)VIP greater than (D-His1)VIP. In rat heart membranes, the order of efficacy was somewhat different: VIP greater than (Ac-His1)VIP = (Phe1)VIP greater than (D-His1)VIP greater than (3-Me-His1)VIP. These data demonstrated the key role of His1 in VIP in activating adenylate cyclase. They suggest that a given VIP analogue might act as full agonist in tightly coupled adenylate cyclase systems (such as those of rat lung and liver membranes) whereas the same analogue could not promote full activity in poorly coupled systems (such as that present in rat brain synaptic membranes).     

The synganglion of the jumping spider Marpissa muscosa (Arachnida: Salticidae): Insights from histology,immunohistochemistry and microCT analysis

Jumping spiders are known for their extraordinary cognitive abilities. The underlying nervous system structures, however, are largely unknown. Here, we explore and describe the anatomy of the brain in the jumping spider Marpissa muscosa (Clerck, 1757) by means of paraffin histology, X-ray microCT analysis and immunohistochemistry as well as three-dimensional reconstruction. In the prosoma, the CNS is a clearly demarcated mass that surrounds the esophagus. The anteriormost neuromere, the protocerebrum, comprises nine bilaterally paired neuropils, including the mushroom bodies and one unpaired midline neuropil, the arcuate body. Further ventrally, the synganglion comprises the cheliceral (deutocerebrum) and pedipalpal neuropils (tritocerebrum). Synapsin-immunoreactivity in all neuropils is generally strong, while allatostatin-immunoreactivity is mostly present in association with the arcuate body and the stomodeal bridge. The most prominent neuropils in the spider brain, the mushroom bodies and the arcuate body, were suggested to be higher integrating centers of the arthropod brain. The mushroom body in M. muscosa is connected to first and second order visual neuropils of the lateral eyes, and the arcuate body to the second order neuropils of the anterior median eyes (primary eyes) through a visual tract. The connection of both, visual neuropils and eyes and arcuate body, as well as their large size corroborates the hypothesis that these neuropils play an important role in cognition and locomotion control of jumping spiders. In addition, we show that the architecture of the brain of M. muscosa and some previously investigated salticids differs significantly from that of the wandering spider Cupiennius salei, especially with regard to structure and arrangement of visual neuropils and mushroom body. Thus, we need to explore the anatomical conformities and specificities of the brains of different spider taxa in order to understand evolutionary transformations of the arthropod brain.     

Role of anterior cingulate cortex inputs to periaqueductal gray for pain avoidance

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Anterior thalamic dysfunction underlies cognitive deficits in a subset of neuropsychiatric disease models

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On the occurrence of Lymnaea auricularia (Gastropoda: Lymnaeidae) in New Zealand

Abstract

The occurrence in New Zealand of Lymnaea auricularia (L.) is recorded for the first time, and its status world-wide is briefly discussed, with particular reference to its role in economic parasitology. The lymnaeid fauna of New Zealand is briefly reviewed.