Ultrasonographic anatomy of the dorsal region of the carpus of the dog

Abstract Traversodontidae is a group of Triassic herbivorous/omnivorous cynodonts that represents the most diversified lineage within Cynognathia. In southern Brazil, a rich fossil record of late Middle/mid-Late Triassic cynodonts has been documented, with Exaeretodon riograndensis Abdala, Barberena, and Dornelles, 2002 and Siriusgnathus niemeyerorum Pavanatto et al., 2018 representing two abundant and well-documented traversodontids. The present study provides a comparative analysis of the morphology of the nasal cavity, nasal recesses, nasolacrimal duct, and maxillary canals of both species using computed tomography, highlighting the changes that occurred in parallel to the origin of mammaliaforms. Our results show that there were no ossified turbinals or a cribriform plate delimiting the posterior end of the nasal cavity, suggesting these structures were probably cartilaginous as in nonmammaliaform cynodonts. Both species show lateral ridges on the internal surface of the roof of the nasal cavity, but the median ridge for the attachment of a nasal septum is absent. Exaeretodon riograndensis and S. niemeyerorum show recesses on the dorsal region of the nasal cavity, which increase the volume of the nasal cavity, potentially enhancing the olfactory chamber and contributing to the sense of smell. On the lateral sides of the nasal cavity, the analyzed taxa show a well-developed maxillary recess. Although E. riograndensis and S. niemeyerorum have roughly similar nasal cavities, in the former taxon, the space between the left and right dorsal recesses of the nasal cavity is uniform along its entire extension, whereas this space narrows posteriorly in S. niemeyerorum. Finally, the nasolacrimal duct of S. niemeyerorum is more inclined anteroposteriorly than in E. riograndensis.

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Activation of dorsal development by contact between the cortical dorsal determinant and the equatorial core cytoplasm in eggs of Xenopus laevis

Development ◽

10.1242/dev.124.8.1543 ◽

1997 ◽

Vol 124 (8) ◽

pp. 1543-1551 ◽

Cited By ~ 1

Author(s):

H. Kageura

Keyword(s):

Xenopus Laevis ◽

Dorsal Side ◽

Equatorial Region ◽

Normal Embryo ◽

Dorsal Region ◽

The Core ◽

Dorsal Axis ◽

The Future ◽

Vegetal Pole ◽

Cell Embryo

In eggs of Xenopus laevis, dorsal development is activated on the future dorsal side by cortical rotation, after fertilization. The immediate effect of cortical rotation is probably the transport of a dorsal determinant from the vegetal pole to the equatorial region on the future dorsal side. However, the identity and action of the dorsal determinant remain problematic. In the present experiments, individual isolated cortices from various regions of the unfertilized eggs and embryos were implanted into one of several positions of a recipient 8-cell embryo. The incidence of secondary axes was used not only to locate the cortical dorsal determinant at different times but also to locate the region of the core competent to respond to the dorsal determinant. The dorsal axis-inducing activity of the cortex occurred around the vegetal pole of the unfertilized egg. During cortical rotation, it shifted from there to a wide dorsal region. This is apparently the first evidence for the presence of a dorsal determinant in the egg cortex. The competence of the core of the 8-cell embryo was distributed in the form of gradient with the highest responsiveness at the equator. These results suggest that, in the normal embryo, dorsal development is activated by contact between the cortical dorsal determinant and the equatorial core cytoplasm, brought together through cortical rotation.

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The Structure, Development, and Operation of the Hinge Ligament of Ostrea edulis

Journal of Cell Science ◽

10.1242/jcs.s3-92.18.129 ◽

1951 ◽

Vol s3-92 (18) ◽

pp. 129-140

Author(s):

E. R. TRUEMAN

Keyword(s):

Surface Area ◽

Outer Layer ◽

Tensile Strain ◽

Central Position ◽

Ostrea Edulis ◽

Structure Development ◽

Dorsal Region ◽

Larval Stages ◽

Adult Oyster

1. The ligamental structure of Ostrea edulis is briefly described. The ligament is situated between the valves of the shell immediately below the urtibo and may be divided into two main layers, the outer and the inner, the principal features of which appear to correspond with those of other bivalves. The outer layer is divided into anterior and posterior halves by the inner layer, which occupies a central position. 2. The axis (hinge or pivotal axis) about which the valves open is situated in the adult oyster along a line drawn through the outer layer and the upper part of the inner layer. When the valves are closed the ligament above this axis is subjected to a tensile strain andthat portion below to compression, the force s so produced causing the opening of the valves. An attempt has been made t o measure this force in relation to the surface area of the valves and it is found to be approximately 4.5 gm.mm./mm.2 This figure is comparable to those obtained when certain other species of bivalves are used. 3. Th eligament is shown to develop from the simple outer layer of the early larval stages, first by the addition of aninner layer and then by growth of this structure chiefly in a ventral direction. The initial dorsal region of the ligamentsoon degenerates and at the same time the pivotal axis moves ventrally between the valves, thus increasing in length. This method of growth is compared with that of an elongate external ligament and the mechanical implications are suggested.

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Corneal sensitivity in five horse breeds

Ciência Rural ◽

10.1590/0103-8478cr20160995 ◽

2017 ◽

Vol 47 (6) ◽

Author(s):

Eunice Santos de Andrade ◽

João Victor Romano Vieira ◽

Deusdete Conceição Gomes Júnior ◽

Ana Claúdia Santos Raposo ◽

Paula Diniz Galera ◽

...

Keyword(s):

Central Region ◽

Dorsal Region ◽

Corneal Sensitivity ◽

Quarter Horse ◽

Arabian Horse ◽

Higher Sensitivity

ABSTRACT: This study aimed to determine and compare corneal sensitivity values in different regions of the cornea in five horse breeds. One hundred and forty five healthy horses, adults of both sexes, of the following breeds - Arabian horse (AH; n=20), Mangalarga Marchador (MM; n=50), Pure Blood Lusitano (PBL; n=35), Quarter Horse (QH; n=20), Brazilian Sport Horse (BSH; n=20)-were investigated. Corneal touch threshold (CTT) was measured with a Cochet-Bonnet esthesiometer in five different corneal regions. Measurements of the median central CTT were: 4.50±0.50cm (AH), 3.50±0.56cm (MM), 3.00±0.25cm (PBL), 2.50±0.44cm (QH) and 2.50±0.00cm (BSH). The central region was the most sensitive and the dorsal region the least sensitive corneal region for all breeds. CTT values differed for corneal regions and horse breeds. The CTT values were different among the corneal regions and the horse breeds. Arabian horses presented higher sensitivity values being the most sensitive in all of the corneal regions.

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Biological parameters of cattle ticks fed on rabbits

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612012000100005 ◽

2012 ◽

Vol 21 (1) ◽

pp. 22-27 ◽

Cited By ~ 2

Author(s):

Maria Alice Zacarias do Amaral ◽

Márcia Cristina de Azevedo Prata ◽

Erik Daemon ◽

John Furlong

Keyword(s):

Developmental Stages ◽

Experimental Studies ◽

Boophilus Microplus ◽

Cattle Tick ◽

Biological Parameters ◽

Dorsal Region ◽

Alternative Hosts ◽

Cattle Ticks ◽

Successive Generations

With the objective of encouraging the use of rabbits as alternative hosts for the cattle tick, four rabbits were infested on the ears and back. From the second day of infestation the developmental stages were observed. e duration of larval engorgement and changes were estimated between six and eight days in the region of the back and between 've and seven days in the pinna. e nymphal engorgement and changes occurred at approximately 10.80 ± 2.65 days in the dorsal and 11.00 ± 2.52 days in the ear, with the engorgement of adults and copulation occurring at 7.03 ± 2.45 days, on the dorsal region and 8.55 ± 1.82 days in the region of the pinna. e parasitic period ranged from 21 to 29 days (back) and from 23 to 30 days (pinna). e engorged females of the back and ear weighed on average 34.43 ± 18.73 and 36.30 ± 18.10 mg, respectively. e nutritional and reproductive e/ciency indexes were 17.38 ± 14.27 and 26.85 ± 17.13% (back) and 17.42 ± 12.22% and 30.70 ± 19.80% (pinna). Although not appropriate to maintain successive generations of Rhipicephalus (Boophilus) microplus, rabbits can be used for di:erent stages of engorgement of the ixodid, allowing experimental studies.

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Distribution of lamprey gonadotropin-releasing hormone in the brain and pituitary gland of larval, metamorphic, and adult sea lampreys, Petromyzon marinus

Canadian Journal of Zoology ◽

10.1139/z94-008 ◽

1994 ◽

Vol 72 (1) ◽

pp. 48-53 ◽

Cited By ~ 26

Author(s):

Glenda M. Wright ◽

Kim M. McBurney ◽

John H. Youson ◽

Stacia A. Sower

Keyword(s):

Pituitary Gland ◽

Preoptic Area ◽

Petromyzon Marinus ◽

Gonadotropin Releasing Hormone ◽

Immunoperoxidase Technique ◽

Dorsal Region ◽

Releasing Hormone ◽

Sea Lampreys ◽

The Brain

Lamprey gonadotropin-releasing hormone was demonstrated in the brains of larval, metamorphic, and adult sea lampreys, Petromyzon marinus, using an immunoperoxidase technique. Gonadotropin-releasing hormone was observed in the neurohypophysis and preoptic area of the brain of larval, metamorphic, juvenile, and prespawning adults. The occurrence of immunoreactive cells and the intensity of the immunostaining was lowest in larvae, but by stage 5 of metamorphosis there was a marked increase in the prevalence and staining of these cells, which continued into adults. In larvae and lampreys in metamorphic stages 1–4, most immunoreactive fibres were confined to the dorsal region of the neurohypophysis. During stage 5 there was an expansion of immunopositive fibres into the ventral portion of the neurohypophysis. Prominent immunoreactivity was observed throughout the neurohypophysis from stage 5 onward through the adult stages. Changes in immunoreactivity of these cells and fibres in the brain and neurohypophysis correlate well with increased concentrations of hormone in the brain during development and with the timing of presumed changes in activity of cells in the adenohypophysis during metamorphosis.

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A Novel Murine Model for theIn VivoStudy of Transdermal Drug Penetration

The Scientific World JOURNAL ◽

10.1100/2012/543536 ◽

2012 ◽

Vol 2012 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

Gábor Erős ◽

Petra Hartmann ◽

Szilvia Berkó ◽

Eszter Csizmazia ◽

Erzsébet Csányi ◽

...

Keyword(s):

Drug Penetration ◽

Titanium Plate ◽

Dorsal Region ◽

Hairless Mice ◽

Continuous Increase ◽

Skin Fold ◽

Exact Measurement ◽

Research Goal ◽

Transdermal Penetration

Enhancement of the transdermal penetration of different active agents is an important research goal. Our aim was to establish a novelin vivoexperimental model which provides a possibility for exact measurement of the quantity of penetrated drug. The experiments were performed on SKH-1 hairless mice. A skin fold in the dorsal region was fixed with two fenestrated titanium plates. A circular wound was made on one side of the skin fold. A metal cylinder with phosphate buffer was fixed into the window of the titanium plate. The concentration of penetrated drug was measured in the buffer. The skin fold was morphologically intact and had a healthy microcirculation. The drug appeared in the acceptor buffer after 30 min, and its concentration exhibited a continuous increase. The presence of ibuprofen was also detected in the plasma. In conclusion, this model allows an exactin vivostudy of drug penetration and absorption.

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Fine structure of the compound eye of the black fly Simulium vittatum (Diptera: Simuliidae)

Canadian Journal of Zoology ◽

10.1139/z87-228 ◽

1987 ◽

Vol 65 (6) ◽

pp. 1454-1469 ◽

Cited By ~ 7

Author(s):

Gail E. O'Grady ◽

Susan B. McIver

Keyword(s):

Fine Structure ◽

Compound Eye ◽

Sensory Receptor ◽

Dorsal Region ◽

Male And Female ◽

Simulium Vittatum ◽

Transmission Electron ◽

Accessory Pigment ◽

Open Rhabdom ◽

Retinular Cells

The fine structure of the ommatidia in light- and dark-adapted eyes of male and female Simulium vittatum Zetterstedt was investigated using scanning and transmission electron microscopy. The male eye is divided into distinct dorsal and ventral regions. The facets in the dorsal region are approximately two times larger than those in the ventral one, which are similar in size to the ones in the female eye. All ommatidia of S. vittatum examined consist of two general regions: a distal dioptric apparatus with bordering primary and accessory pigment and Semper cells, and a sensory receptor layer. Each ommatidium in the female eye and ventral eye of the male has eight retinular cells (R cells): six peripheral (R1–6) and two central (R7, R8). R7 occurs distally and R8 basally. Strikingly, the ommatidia in the dorsal eye of the male lack the R7 cell. In all ommatidia, rhabdomeres on the inner surface of the peripheral R cells are separate throughout their length, creating an open rhabdom. A greater diameter of corneal facets, elongated peripheral R cells, and perhaps the lack of the R7 cell are specializations of the dorsal region of the eye that help the male to detect small, rapidly moving females against the skylight as they fly above the swarm of males. Differences observed between light- and dark-adapted eyes of male and female S. vittatum were the same and were associated with the internal components of the peripheral R cells.

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Two visual pigment opsins, one expressed in the dorsal region and another in the dorsal and the ventral regions, of the compound eye of a dragonfly,Sympetrum frequens

Invertebrate Neuroscience ◽

10.1007/bf02214177 ◽

1996 ◽

Vol 2 (3) ◽

pp. 209-209 ◽

Cited By ~ 1

Author(s):

Kentaro Arikawa ◽

Koichi Ozaki ◽

Takanari Tsuda ◽

Junko Kitamoto ◽

Yuji Mishina

Keyword(s):

Visual Pigment ◽

Compound Eye ◽

Dorsal Region ◽

Sympetrum Frequens

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Occurrence of Amblyomma rotundatum Koch, 1844 on Epicrates assisi Machado, 1945 in João Pessoa, Paraíba, Brazil

Acta Veterinaria Brasilica ◽

10.21708/avb.2021.15.4.10147 ◽

2021 ◽

Vol 15 (4) ◽

pp. 335-338

Author(s):

Aksa Ingrid Vieira Batista ◽

Gabriel Vinicius Carvalho de Lucena ◽

Kleber Silva de Oliveira Filho ◽

Thiago Ferreira Lopes Nery ◽

Thiago Fernandes Martins ◽

...

Keyword(s):

Host Species ◽

Tick Species ◽

Wide Distribution ◽

Dorsal Region ◽

Taxonomic Key ◽

Caatinga Biome ◽

First Occurrence ◽

First Time ◽

Semi Arid

The Caatinga rainbow boa (Epicrates assisi Machado, 1945) is a snake belonging to the order Squamata, family Boidae, and subfamily Boinae. It has a wide distribution in Brazil and can be found in the Caatinga biome. The present study aims to report the first occurrence of Amblyomma rotundatum on E. assisi in the municipality of João Pessoa, Paraíba State (PB). On March 3, 2020, a tick collection was performed on the dorsal region of the head of an E. assisi, which was captive at the Arruda Câmara Zoobotanical Park, João Pessoa-PB. After collecting the tick, it was transferred to a flask containing 70º alcohol and sent to the Laboratory of Animal Parasitology of the Federal Rural University of the Semi-Arid (UFERSA) for analysis. Identification was done with the aid of a stereomicroscope using a taxonomic key. The result identified this specimen as a nymph of A. rotundatum. The occurrence of this tick species on E. assisi is reported for the first time and constitutes new data applicable to the ectoparasites that occur in this host species in Brazil.

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