Anatomical and Functional Study of the Ostrich () Lung through Macroscopic Analysis in Combination with Optical and Electron Microscopy Techniques.

The Ostrich occupies a unique position as the largest bird on the planet. Like other ratites, it has been reputed to have a phylogenetically primitive lung. We used macroscopy, light microscopy, transmission and scanning electron microscopy as well as silicon rubber casting to elucidate the functional design of its lung and compare it with what is already documented for the avian species.

Methods of In Ovo and Ex Ovo Ostrich Embryo Culture with Observations on the Development and Maturation of the Chorioallantoic Membrane.

Culture of shell-free and windowed eggs for drug testing and other experiments has been perfected for smaller eggs such as those of chickens, where the developing blood vessels of the chorioallantoic membrane (CAM) become accessible for manipulative studies. However, due to the thickness and hardness of the ostrich egg shell, such techniques are not applicable. Using a tork craft mini rotary and a drill bit, we established windowed egg, in-shell-membrane windowed egg, and in-shell-membrane shell-free methods in the ostrich egg, depending on whether the shell membranes were retained or not.

Morphometric and stereological methods for quantifying the coarse structural parameters of the ruminal tissues in sheep.

In ruminants, the rumen is the largest and most significant fore-stomach. Stereological analysis of important structural parameters that may be used to assess the functional capacity of the rumen is lacking. In the current investigation, five rams were used to demonstrate the methods for quantifying salient structural parameters related to rumen function.

Slight volume changes in the duck lung do not imply a fundamental change in the structure of the parenchyma.

Slight changes in lung volume have previously been reported in ducks. We studied the functional structure of the lung of the domestic duck using classical anatomical techniques as well as ultrasound monitoring to unravel the causes of such changes. Later dorsal and medioventral secondary bronchi were superficially positioned and covered with a thin transparent and collapsible membrane, internally lined with a cuboidal to squamous epithelium.

SDF-1/CXCR4 signalling is involved in blood vessel growth and remodelling by intussusception.

The precise mechanisms of SDF-1 (CXCL12) in angiogenesis are not fully elucidated. Recently, we showed that Notch inhibition induces extensive intussusceptive angiogenesis by recruitment of mononuclear cells and it was associated with increased levels of SDF-1 and CXCR4. In the current study, we demonstrated SDF-1 expression in liver sinusoidal vessels of Notch1 knockout mice with regenerative hyperplasia by means of intussusception, but we did not detect any SDF-1 expression in wild-type mice with normal liver vessel structure.

Publisher Correction: Synergistic interaction of sprouting and intussusceptive angiogenesis during zebrafish caudal vein plexus development.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Synergistic interaction of sprouting and intussusceptive angiogenesis during zebrafish caudal vein plexus development.

Intussusceptive angiogenesis (IA) is a complementary method to sprouting angiogenesis (SA). The hallmark of IA is formation of trans-capillary tissue pillars, their fusion and remodeling of the vascular plexus. In this study, we investigate the formation of the zebrafish caudal vein plexus (CVP) in Tg(fli1a:eGFP) and the synergistic interaction of IA and SA in crafting the archetypical angio-architecture of the CVP.

Endoglin inhibition leads to intussusceptive angiogenesis via activation of factors related to COUP-TFII signaling pathway.

Angiogenesis is a highly coordinated, extremely complex process orchestrated by multiple signaling molecules and blood flow conditions. While sprouting mode of angiogenesis is very well investigated, the molecular mechanisms underlying intussusception, the second mode of angiogenesis, remain largely unclear. In the current study two molecules involved in vascular growth and differentiation, namely endoglin (ENG/CD105) and chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) were examined to unravel their specific roles in angiogenesis.

Dynamics of the Developing Chick Chorioallantoic Membrane Assessed by Stereology, Allometry, Immunohistochemistry and Molecular Analysis.

The chick chorioallantoic membrane (CAM) is a widely used model for the study of angiogenesis, tumour growth, as well as drug efficacy. In spite of this, little is known about the developmental alteration from its appearance to the time of hatching. In the current study the CAM has been studied by classical stereology and allometry.

Membrane mediated development of the vertebrate blood-gas-barrier.

During embryonic lung development, establishment of the gas-exchanging units is guided by epithelial tubes lined by columnar cells. Ultimately, a thin blood-gas barrier (BGB) is established and forms the interface for efficient gas exchange. This thin BGB is achieved through processes, which entail lowering of tight junctions, stretching, and thinning in mammals.

Avian area vasculosa and CAM as rapid in vivo pro-angiogenic and antiangiogenic models.

Angiogenesis, the development of new blood vessels from preexisting ones, is driven by coordinated signaling pathways governed by specific molecules, hemodynamic forces, and endothelial and periendothelial cells. The processes involve adhesion, migration, and survival machinery within the target endothelial and periendothelial cells. Factors that interfere with any of these processes may therefore influence angiogenesis either positively (pro-angiogenesis) or negatively (antiangiogenesis).

Effects of anticancer drug docetaxel on the structure and function of the rabbit olfactory mucosa.

Docetaxel (DCT) is an anticancer drug which acts by disrupting microtubule dynamics in the highly mitotic cancer cells. Thus, this drug has a potential to affect function and organization of tissues exhibiting high cellular turnover. We investigated, in the rabbit, the effects of a single human equivalent dose (6.

Casting materials and their application in research and teaching.

From a biological point of view, casting refers to filling of anatomical and/or pathological spaces with extraneous material that reproduces a three-dimensional replica of the space. Casting may be accompanied by additional procedures such as corrosion, in which the soft tissue is digested out, leaving a clean cast, or the material may be mixed with radiopaque substances to allow x-ray photography or micro computed topography (µCT) scanning. Alternatively, clearing of the surrounding soft tissue increases transparency and allows visualization of the casted cavities.

Erythrina abyssinica prevents meningoencephalitis in chronic Trypanosoma brucei brucei mouse model.

Human African trypanosomiasis is prevalent in Sub-sahara African countries that lie between 14° North and 29° south of the equator. Sixty million people are at risk of infection. Trypanosoma brucei gambesience occurs in West and Central Africa while Trypanosoma brucei rhodesience occurs in East and Southern Africa.

Inhibition of Notch signaling induces extensive intussusceptive neo-angiogenesis by recruitment of mononuclear cells.

Notch is an intercellular signaling pathway related mainly to sprouting neo-angiogenesis. The objective of our study was to evaluate the angiogenic mechanisms involved in the vascular augmentation (sprouting/intussusception) after Notch inhibition within perfused vascular beds using the chick area vasculosa and MxCreNotch1(lox/lox) mice. In vivo monitoring combined with morphological investigations demonstrated that inhibition of Notch signaling within perfused vascular beds remarkably induced intussusceptive angiogenesis (IA) with resultant dense immature capillary plexuses.

Development and remodeling of the vertebrate blood-gas barrier.

During vertebrate development, the lung inaugurates as an endodermal bud from the primitive foregut. Dichotomous subdivision of the bud results in arborizing airways that form the prospective gas exchanging chambers, where a thin blood-gas barrier (BGB) is established. In the mammalian lung, this proceeds through conversion of type II cells to type I cells, thinning, and elongation of the cells as well as extrusion of the lamellar bodies.

Morphofunctional adaptations of the olfactory mucosa in postnatally developing rabbits.

Rabbits are born blind and deaf and receive unusually limited maternal care. Consequently, their suckling young heavily rely on the olfactory cue for nipple attachment. However, the postnatal morphofunctional adaptations of olfactory mucosa (OM) are not fully elucidated.

Decrease in VEGF expression induces intussusceptive vascular pruning.

Objective: The concept of vascular pruning, the "cuting-off" of vessels, is gaining importance due to expansion of angio-modulating therapies. The proangiogenic effects of vascular endothelial growth factor (VEGF) are broadly described, but the mechanisms of structural alterations by its downregulation are not known.

Methods And Results: VEGF(165)-releasing hydrogels were applied onto the chick chorioallantoic membrane on embryonic day 10.

Escape mechanisms after antiangiogenic treatment, or why are the tumors growing again?

Inhibitors of angiogenesis and radiation induce compensatory changes in the tumor vasculature both during and after cessation of treatment. In numerous preclinical studies, angiogenesis inhibitors were shown to be efficient in the treatment of many pathological conditions, including solid cancers. In most clinical trials, however, this approach turned out to have no significant effect, especially if applied as monotherapy.

Spatial and functional relationships between air conduits and blood capillaries in the pulmonary gas exchange tissue of adult and developing chickens.

The documented data regarding the three-dimensional structure of the air capillaries (ACs), the ultimate sites of gas exchange in the avian lung is contradictory. Further, the mode of gas exchange, described as cross-current has not been clearly elucidated. We studied the temporal and spatial arrangement of the terminal air conduits of the chicken lung and their relationship with the blood capillaries (BCs) in embryos as well as the definitive architecture in adults.

Comparative functional structure of the olfactory mucosa in the domestic dog and sheep.

Olfactory acuity differs among animal species depending on age and dependence on smell. However, the attendant functional anatomy has not been elucidated. We sought to determine the functional structure of the olfactory mucosa in suckling and adult dog and sheep.

Intussusceptive angiogenesis and its role in vascular morphogenesis, patterning, and remodeling.

New blood vessels arise initially as blood islands in the process known as vasculogenesis or as new capillary segments produced through angiogenesis. Angiogenesis itself encompasses two broad processes, namely sprouting (SA) and intussusceptive (IA) angiogenesis. Primordial capillary plexuses expand through both SA and IA, but subsequent growth and remodeling are achieved through IA.

The structural design of the bat wing web and its possible role in gas exchange.

The structure of the skin in the epauletted fruit bat (Epomophorus wahlbergi) wing and body trunk was studied with a view to understanding possible adaptations for gas metabolism and thermoregulation. In addition, gas exchange measurements were performed using a respirometer designed for the purpose. The body skin had an epidermis, a dermis with hair follicles and sweat glands and a fat-laden hypodermis.

Microvascular growth, development, and remodeling in the embryonic avian kidney: the interplay between sprouting and intussusceptive angiogenic mechanisms.

Embryonic development is associated with extensive vascular growth and remodeling. We used immunohistochemical, light and electron microscopical techniques, as well as vascular casting methods to study the developing chick embryo kidney with special attention to the interplay between sprouting and intussusceptive vascular growth modes. During inauguration at embryonic day 5 (E5), the early mesonephros was characterised by extensive microvascular sprouting.