Mast cells in the developing avian eye

Mast cells are present in the eye of Gallus domesticus, appearing in the anterior uvea in embryos at stage 39 HH (13th day). In hatching and adult birds, they are present in the sclera, uvea, pectinate Ligament, and conjunctiva. Mast cells are absent in the cornea, retina, and pecten oculi.Maturing mast cells in the anterior eye segment appear as round cells having eccentric nuclei and a few cytoplasmic metachromatic granules, whose fluorescence increases during development. Mature cells are more numerous in late development, and their cytoplasm is rich in metachromatic and intensely fluorescent granules. Ultrastructurally, maturing mast cells display progranules and a few electron dense and homogeneous granules on one side of the cell. Mast cells of adult birds possess homogeneous cytoplasmic granules, some of which display protuberances that penetrate hollows of adjoining granules. Heterogeneous granules exhibiting latticed and mottled patterns are also present. The existence of mast cells in the anterior eye segment indicates that these cells might perform a physiological role during development and in aqueous humor outflow. They might modulate exchanges between blood and aqueous humor through chemical mediators present in their granules. (C) 1996 Wiley-Liss, Inc.

The use of apatite fission track thermochronology to constrain fault movements and sedimentary basin evolution in northeastern Brazil

An apatite fission track study of crystalline rocks underlying sedimentary basins in northeastern Brazil indicate that crustal blocks that occur on opposite sides of a geological fault experienced different thermal histories. Samples collected on the West block yielded corrected fission-track ages from 140 to 375 Ma, whereas samples collected on the East block yielded ages between 90 and 125 Ma. The thermal models suggest that each block experienced two cooling events separated by a heating event at different times. We concluded that the West block moved downward relative to the East block ca. 140 Ma ago, when sediments eroded from the East side were deposited on the West side. This process represents the early stage of sedimentary basin formation and the opening of the South Atlantic Ocean in the region. Downward and upward movements related to heating and cooling events of these crustal blocks at different periods until recent times are proposed. (c) 2005 Elsevier Ltd. All rights reserved.

Effects of direction and curvature on variable error pattern of reaching movements

A number of studies have analyzed various indices of the final position variability in order to provide insight into different levels of neuromotor processing during reaching movements. Yet the possible effects of movement kinematics on variability have often been neglected. The present study was designed to test the effects of movement direction and curvature on the pattern of movement variable errors. Subjects performed series of reaching movements over the same distance and into the same target. However, due either to changes in starting position or to applied obstacles, the movements were performed in different directions or along the trajectories of different curvatures. The pattern of movement variable errors was assessed by means of the principal component analysis applied on the 2-D scatter of movement final positions. The orientation of these ellipses demonstrated changes associated with changes in both movement direction and curvature. However, neither movement direction nor movement curvature affected movement variable errors assessed by area of the ellipses. Therefore it was concluded that the end-point variability depends partly, but not exclusively, on movement kinematics.

Effects of displacement and trajectory length on the variability pattern of reaching movements

The design of the present study enabled the authors to distinguish between the possible effects of movement displacement and trajectory length on the pattern of final positions of planar reaching movements. With their eyes closed, 9 subjects performed series of fast and accurate movements from different initial positions to the same target. For some series, the movements were unconstrained and were therefore performed along an approximately straight vertical line. For other series, an obstacle was positioned so that trajectory length was increased because of an increase in movement curvature. Ellipses of variability obtained by means of principal component analysis applied to the scatter of movement final positions enabled the authors to assess the pattern of movement variable errors. The results showed that the orientation of the ellipses was not affected by movement displacement or by trajectory length, whereas variable errors increased with move ment displacement. An increase in trajectory length as a consequence of increased curvature caused no change in variable error. From the perspective of current motor control theory, that finding was quite unexpected. Further studies are required so that one can distinguish among the possible effects of various kinematics, kinetics, and other variables that could affect the pattern of variable errors of reaching movements.

B-mode ultrasonography biometry of the Amazon Parrot (Amazona aestiva) eye

PurposeUltrasonographic evaluation of the eye is a relatively recent addition to routine ophthalmic diagnostics in small animal ophthalmology. Some parameters for ophthalmic biometry have been established. There are few studies in clinical avian ophthalmology that describe ultrasound images of eye in some nocturnal avian species and in other birds that do not belong to the Brazilian fauna, but the psittacine family is not represented. The purpose of this study was to describe the following measurements: the distances between cornea and anterior lens capsule (D1) between the anterior and posterior lens capsule (D2), between posterior lens capsule and optic papilla (D3) and the axial length.MethodSixty four transpalpebral ocular ultrasound examinations were performed on 32 Blue fronted Amazon parrots (Amazona aestiva) with no history of previous ophthalmic disease.Result and DiscussionThe measurements were taken in sagital planes using a 10 MHz linear probe without a standoff pad. The mean values for the left eye were; D1 0.17 +/- 0.03 cm, D2 0.35 +/- 0.02 cm, D3 0.73 +/- 0.04 cm and the axial length 1.26 +/- 0.06 cm. In the right eye D1 0.17 +/- 0.02 cm, D2 0.34 +/- 0.02 cm, D3 0.74 +/- 0.03 cm and the axial length 1.25 +/- 0.05 cm. No significant statistical difference was observed among the birds or between the left and right eye. The description of these parameters will allow the veterinary practitioner to evaluate the structural changes that specific diseases may cause in these animals.

The correlation between subordinate fish eye colour and received attacks: a negative social feedback mechanism for the reduction of aggression during the formation of dominance hierarchies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electromyographic study of levator scapulae and rhomboideus major muscles in movements of the shoulder and arm

In 21 normal adult male subjects, the muscular activity of the levator scapulae and rhomboideus major muscles was studied electromyographically during the movements of the shoulder and arm. Two single coaxial needle electrodes were used for registering the action potentials. Concerning shoulder movement, it was shown that the levator scapulae was active in elevation and rhomboideus major was active in retraction. Both muscles were inactive during protrusion, in most events. Concerning free movements of the arm, both muscles were active in abduction, elevation, adduction, flexion and circumduction, but inactive in extension. During the same movements, performed with a load, we observed greater intensity in the activity of these muscles in comparison to their activity during free movements.

Electromyographic study of the trapezius (middle portion) and rhomboideus major muscles in movements of the trunk

The authors studied the trapezius (middle portion) and rhomboideus major muscles in movements of flexion, extension, inclination and rotation of the trunk. The electromyographic records demonstrate that such muscles show activity only at the ending of flexion, being inactive in the other movements.

the human hand. I. Movements of the index ANALYSE ELECTROMYOGRAPHIQUE DU PREMIER MUSCLE INTEROSSEUX DORSAL DE LA MAIN HUMAINE

An electromyographic study of the musculus interosseus dorsalis was performed on the right hand of 25 young adult male right-handed volunteers. The electrodes, simple coaxial needles, were implanted one at the ulnar head and the other at the radial head of the muscle. The muscles were analyzed during free movements of the index and against resistance. The same movements were done in four different positions of the fore-arm and hand, without variation in the results for each one of the movements. There was no significant difference between the activities of the ulnar head and radial head. During freely performed movements, muscle activity was recorded only during abduction. During movements against resistance, muscle activity was completely nil only during adduction; during the remaining movements, however, moderate (2+), strong (3+) and very strong activity (4+) was recorded.

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in free movements of the head

The authors studied the trapezius (pars media) and rhomboideus major muscles in movements of flexion, extension, inclination and rotation of the head. The electromyographic records demonstrated that referred muscles are inactive in these different movements.

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in movements of the arm (part 1)

The participation of the trapezius (pars media) and rhomboideus major muscles in free movements of abduction, adduction, flexion, extension and hyperextension of the arm was studied electromyographically. These muscles were active and synergic in all analysed movements, both acting with intensity that ranged from moderate to very marked.

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in movements of the arm (part 2)

The participation of the trapezius (pars media) and rhomboideus major muscles were studied electromyographically in movements of lateral and medial rotation (free and against resistance) of the arm. In the majority of cases both muscles were inactive during the performance of the analysed movements. Cases in which only one or both muscles acted in free rotation occurred only at the second half or ending of the movement. Records of electrical potentials during against resistance rotation were due to tensional efforts at the shoulder level.