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Anterior Half (anterior + half)
Selected AbstractsStudy by transmission and scanning electron microscopy of the morphogenesis of three types of lingual papillae in the albino rat (Rattus rattus)ACTA ZOOLOGICA, Issue 3 2010Ahlam Mostafa El-Bakry Abstract El-Bakry, A.M. 2010. Study by transmission and scanning electron microscopy of the morphogenesis of three types of lingual papillae in the albino rat (Rattus rattus).,Acta Zoologica (Stockholm) 91: 267,278 Tongues were removed from albino rat foetus on days 12 (E12) and 16 (E16) of gestation and from newborns (P0) and from juvenile rats on days 7 (P7), 14 (P14) and 21 (P21) postnatally for investigation by light, scanning, and transmission electron microscopy. Significant changes appeared during the morphogenesis of the papillae. At E12, two rows of rudiments of fungiform papillae were extended bilaterally on the anterior half of the tongue. At E16, the rudiments of fungiform papillae were regularly arranged in a lattice-like pattern. A rudiment of circumvallate papillae could be recognized. No rudiment of filiform papillae was visible. No evidence of keratinization was recognizable. At P0, rudiments of filiform papillae were visible but had a more rounded appearance, with keratinization. The fungiform and circumvallate papillae were large and their outlines were somewhat irregular as that found in the adult rat. At P7, the filiform papillae were large and slender. The fungiform papillae became large and the shape of circumvallate papillae was almost similar to that observed in the adult. At P14 and P21, the shape and structure of the three types of papillae were irregular as those found in the adult. In conclusion, the rudiments of the fungiform and circumvallate papillae were visible earlier than those of the filiform papillae. The morphogenesis of filiform papillae advanced in a parallel manner with the keratinization of the lingual epithelium, in the period from just before birth to a few weeks after birth. [source] Anatomy of executive deficit following ruptured anterior communicating artery aneurysmEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2009O. Martinaud Background and purpose:, To evaluate behavioral and cognitive deficits following anterior communicating artery aneurysm rupture and determine critical lesion locations. Methods:, We investigated 74 patients with standardized cognitive tests and behavioral inventory. Two examiners rated MRI signal abnormalities in 51 predetermined regions of interest. Classification tree analysis was used to select regions associated with each cognitive deficit. Results:, Eleven patients presented behavioral executive deficits and 10 had cognitive executive deficit. Their presence depended on left hemisphere lesions only: (i) ventral striatum lesion was associated with behavioral executive deficit (P = 0.04), reduction of activities (P = 0.01), and hyperactivity (P = 0.02); (ii) superior frontal gyrus lesion, with cognitive executive deficit (P = 0.01), action initiation deficit (P = 0.02), and rule deduction deficit (P = 0.02); (iii) anterior half of centrum semiovale lesion, with Stroop inhibition deficit (P = 0.02); (iv) medial superior and middle frontal gyri lesions, with task coordination deficit (P = 0.01); and (v) middle frontal gyrus lesion, with words generation deficit (P = 0.02). Conclusion:, This study supports that (i) cognitive executive deficits depend mostly on lateral prefrontal lesions, (ii) with locations varying according to executive process, and (iii) behavioral executive deficits are mainly due to left ventral striatum lesion in post-aneurysmal damage. [source] Structure of the human tibialis anterior tendonJOURNAL OF ANATOMY, Issue 4 2000WOLF PETERSEN The structure and vascular pattern of the human tibialis anterior tendon was investigated using injection techniques, light and transmission electron microscopy and immunohistochemistry. From the well vascularised peritenon, blood vessels penetrate the tendon tissue and anastomose with a longitudinally oriented intratendinous network. The distribution of blood vessels within the tibialis anterior tendon was not homogenous. The posterior part of the tendon had a complete vascular network that extends from the musculotendinous junction to the insertion at the first metatarsal and medial cuneiform bones. In the anterior half, the tissue was avascular in a zone with a length of 45,67 mm. This zone was covered by a single layer (,30 ,m) of oval shaped cells. Transmission electron microscopy showed that these cells have the characteristics of chondroid cells. This region was stained by Alcian blue at pH 1 which indicates a high concentration of acid glycosaminoglycans and immunohistochemical staining for chondroitin-4-sulphate, chondroitin-6-sulphate and aggrecan was positive. However, immunostaining for the typical cartilage specific type II collagen within this zone was negative. The location of the avascular zone corresponds to the region where the tibialis anterior tendon wraps around the superior and inferior retinacula which serve as fibrous pulleys. This is the region where most spontaneous ruptures of the tibialis anterior tendon occur. The presence of fibrocartilage within gliding tendons is a functional adaptation to compressive and shearing forces. In contrast to reports from the literature about the structure of gliding tendons wrapping around a bony pulley, the gliding zone of the tibialis anterior tendon has only a narrow layer of chondroid cells and proof of type II collagen is lacking. [source] Colonization by barnacles on fossil Clypeaster: an exceptional example of larval settlementLETHAIA, Issue 4 2008ANA G. SANTOS The presence of c. 1450 individuals of the balanid barnacle Balanus crenatus Bruguière encrusting the test of a clypeasteroid sea urchin from the Late Miocene of the Guadalquivir Basin (southwestern Spain) allows proposing a settlement pattern linked to the growth of the encrusting organism. The possible influence of dip angle was controlled by dividing the test into four concentric zones ranging from lowest margin to apex (0,15°, 15,30°, 30,50° and 0°). Contour diagrams were prepared to identify areas of highest barnacle density as well as size categories distribution in relationship to the pitch of the sea urchin test. The orientation of balanid tests was recorded and plotted on rose diagrams from 0° to 180°. Four size categories of barnacles were distinguished: (1) < 1 mm, (2) 1,2 mm, (3) 2,3 mm and (4) 3,4 mm; these correspond to a growth sequence ranging from post-larval forms to juveniles. Two areas of maximum settlement density are situated on the posterior margin of the test, on aboral as well as oral surfaces. The aboral surface shows the maximum number of barnacles. Two groups of individuals are defined on the basis of their location, that is, those encrusting the posterior medium part of the urchin, and those located on the anterior half. The results suggest that larval settlement was initially controlled by the availability of free space and afterwards by an intensification effect. Orientation and dip of the test may have played a secondary role in the settlement of the larvae. Substrate colonization seems to have been closely related to the biostratinomic history of the sea urchin test and although several scenarios are possible, our data are congruent with a synchronous settlement of both surfaces (aboral and oral) by one spat or several. [source] | ||||||||||