Developmental events and cellular changes occurred during esophageal development of quail embryos

Immunohistochemical-properties of the dermal embryonic telocytes

The current investigation aims to study the embryonic dermis formed in the early stages of development and identify the initial interstitial components of the dermis that serve as biological and structural scaffolds for the development of the dermal tissue. To investigate the dermal structure, the current study used morphological and immunological techniques. TCs identified by TEM. They had a cell body and unique podomeres and podoms. They formed a 3D network spread throughout the dermis. Homocellular contact established between them, as well as heterocellular contacts with other cells. Immunohistochemical techniques using specific markers for TCss CD34, CD117, and VEGF confirmed TC identification. TCs represent the major interstitial component in the dermal tissue. They established a 3D network, enclosing other cells and structures. Expression of VEGF by TC promotes angiogenesis. TCs establish cellular contact with sprouting endothelial cells. At the site of cell junction with TCs, cytoskeletal filaments identified and observed to form the pseudopodium core that projects from endothelial cells. TCs had proteolytic properties that expressed MMP-9, CD68, and CD21. Proteolytic activity aids in the removal of components of the extracellular matrix and the phagocytosis of degraded remnants to create spaces to facilitate the development of new dermal structures. In conclusion, TCs organized the scaffold for the development of future dermal structures, including fibrous components and skin appendages. Studying dermal TCs would be interested in the possibility of developing therapeutic strategies for treating different skin disorders and diseases.

Developmental morpho-analysis of the caecum in Japanese quail embryos (Coturnix coturnix japonica)

In the current study, we are focusing on the microanatomical structure of quail caecum during the prehatching time to try to understand the function and the role of each cell-built quail caecum reaching how caecum plays an essential role in immunity and absorption. The morpho-developmental features of the quail caecum were described in detail daily from the third incubation day (ID) till hatching time, investigating the gross morphology, microscopic, and ultrastructure using light and scanning electron microscope. The embryonic caecum appeared grossly as two lateral outpocketings with blinded ends, emerging laterally at the junction between the small and large intestine (the ileocaecal junction). The primordia of two caeca, represented by two lateral swellings from the hindgut on the fourth ID, continued growing till the day of hatching, where the caecal wall consisted of three apparent layers: mucosa, musculosa, and serosa. At the time of hatching, the quail caecum was still not fully mature and will continue growing posthatching. The findings in this study can be applied in further studies intended to understand the physiological mechanisms of the caecum during prehatching and posthatching periods. RESEARCH HIGHLIGHTS: Caecum is one of the hindgut derivatives that started as two lateral swellings. The caecal wall consisted of three layers; mucosa, musculosa, and serosa. The caecum plays an essential role in immunity maintenance. Caecum continues to grow posthatching as it is not fully mature at hatching time.

Immunohistochemical properties of embryonic telocytes in a myogenic microenvironment

Telocytes are a unique interstitial cell type that functions in adulthood and embryogenesis. They have characteristic immunohistochemical phenotypes while acquiring different immunohistochemical properties related to the organ microenvironment. The present study aims to investigate the immunohistochemical features of embryonic telocytes during myogenesis and describe their morphology using light microscopy and TEM. Telocytes represent a major cellular constituent in the interstitial elements. They had distinguished telopodes and podoms and formed a 3D interstitial network in the developing muscles. They formed heterocellular contact with myoblasts and nascent myotubes. Telocytes also had distinctive secretory activity. Telocytes identified by CD34. They also express CD68 and MMP-9 to facilitate the development of new tissues. Expression of CD21 by telocytes may reveal their function in immune defense. They also express VEGF, which regulates angiogenesis. In conclusion, the distribution and immunological properties of telocytes in the myogenic tissue indicate that telocytes provide biological and structural support in the development of the myogenic tissue architecture and organization.

Histological and ultrastructural characterization of the dorso-ventral skin of the juvenile and the adult starry puffer fish (Arothron stellatus, Anonymous 1798)

BACKGROUND

The starry puffer fish (Arothron stellatus, Anonymous, 1798) is a poisonous tetradontidae fish inhabiting the Red sea. The skin constitutes an important defense against any external effects. The study aims to characterize the dorso-ventral skin of the juvenile and the adult starry puffer fish using light and scanning electron microscopies. Twenty specimens of juvenile and adult fresh fishes were used.

RESULTS

The scanning electron microarchitecture of the skin of the juvenile and adult fish showed delicate irregular-shaped protrusions, and well-defined bricks-like elevations on the dorsal side and interrupted folds as well as irregular-shaped protrusions on the ventral side. In adult fish, the patterned microridges of the superficial and deep epithelial cells (keratinocytes) were larger and well-defined in the dorsal skin than in the ventral side, the contrary was seen in the juvenile fish. The microridges were arranged in a fingerprint or honeycomb patterns. The openings of the mucous cells were more numerous in the dorsal skin in both age stages but more noticeable in adult. Furthermore, the sensory cells were more dominant in the juveniles than the adults. The odontic spines were only seen in adult. Histologically, few taste buds were observed in the epidermis of the dorsal skin surface of the adult fish. Both mucous and club cells were embedded in the epidermis of the juvenile and adult fish with different shapes and sizes. Melanophores were observed at the dorsal skin of both juvenile and adult fishes while fewer numbers were noticed at the ventral surfaces. Several dermal bony plates with different shapes and sizes were demonstrated in the skin of both adult and juvenile fishes.

CONCLUSION

The structural variations of skin of the juvenile and adult fishes may reflect the various environmental difficulties that they confront.

Preen gland of the laughing dove (Streptopelia senegalensis aegyptiaca): Light and electron microscopic analysis

This work reviews the microscopic anatomy of the preen gland in laughing dove (Streptopelia senegalensis aegyptiaca) using light, scanning, and transmission electron microscopes. The gland possessed two large pea-shaped lobes. The glandular lobules of each lobe were huddled in elliptical, triangle, round shapes, connected with each other by strands of connective tissue septae. The lobule was composed of glandular follicles, each follicle folded and enclosed by a sheath of connective tissue connected with the neighboring ones by interfollicular septae. The gland's parenchyma was coated with a dense connective tissue capsule composed of collagen, elastic, and reticular fibers. The secretory tubules were divided into peripheral tubules and central tubules. The central ones were located close to the major cavity and lined with thin epithelium, whereas the peripheral tubules were adjacent to the capsule and characterized by taller epithelium. The central secretory tubules were lined with four cell layers: flattened basal, large-sized polyhedral intermediate, and secretory cell layers, as well as a degenerative cells layer that formed of small cells with pale cytoplasm and pyknotic nuclei. Variable sizes and shapes of Herbst corpuscles were detected alongside the papillary duct and near the glandular lobe. Transmission electron microscopy view revealed that the cytoplasm of the intermediate cells contained a dense population of mitochondria, while the secretory and degenerative cells contained fewer mitochondria. In conclusion, these structures will be beneficial for understanding the habitat differences of laughing doves. RESEARCH HIGHLIGHTS: Grossly, the preen gland (PG) of the laughing dove formed of two large pea-shaped lobes. The glandular lobule was composed of glandular follicles, each follicle was folded and enclosed by a sheath of connective tissue connected with the neighboring ones by interfollicular septae. The central secretory tubules were lined with four cell layers: basal, intermediate, secretory, and degenerative cell layers. Variable sizes and shapes of Herbst corpuscles were detected alongside the papillary duct and near the glandular lobe of the PG. In transmission electron microscopic analysis, the cytoplasm of the intermediate cells contained a dense population of mitochondria, while the secretory and degenerative cells contained fewer mitochondria.

Isolation and culture of chicken bone marrow-derived CD34+ hematopoietic stem and progenitor cells and induced differentiation to myeloid cells

Hematopoietic stem and progenitor cell (HSPC) research will help elucidate the pathogenesis of hematologic diseases. The present study aimed to establish an isolation method and culture system for chicken bone marrow (BM)-derived HSPCs and test their proliferation and differentiation abilities. Mononuclear cells were collected from chicken BM, and CD34+ HSPCs were isolated. Then, the cells were cultured in media with different cytokine compositions, and the growth status, cell phenotype, and morphological appearance of the cells were analyzed at different time points. Our results showed that Iscove's Modified Dulbecco's Medium supplemented with 50 ng/mL stem cell factor, 30 ng/mL Flt-3 ligand, 10 μg/mL interleukin 3, 50 ng/mL interleukin 6%, and 10% chicken serum supported chicken CD34+ HSPC survival ex vivo for approximately 10 d. Further, 80 ng/mL granulocyte-colony stimulating factor and 30 ng/mL granulocyte macrophage-colony stimulating factor were added into the above culture system to form a myeloid cell differentiation induction culture system. After culturing in this system for 72 h, approximately 66% of chicken CD34+ HSPCs exhibited a CD11b+ phenotype, indicating that HSPCs differentiated into myeloid cells. In conclusion, chicken BM-derived CD34+ cells possess HSPC characteristics that can self-renew and differentiate into myeloid cells in a culture medium containing growth factors.

Pre-gastric secretory epithelium: A light, scanning and transmission electron microscopic study of an epithelial modification of the esophagus in embryonic quails

The current study investigated epithelial modification of embryonic quail esophagus using gross examination, light microscopy, transmission and scanning electron microscopy. By semithin sections, the pre-gastric modified region had unfolded mucosa, formed epithelial flabs and pockets, and had reduced muscularis mucosae, thin muscular layer, less glandular tissue, and outer esophageal groove. Conversely, the normal esophageal mucosa was folded, had abundant glandular tissue and prominent muscularis mucosae, with two muscular layers; the outer and the inner. The modified epithelium resembled stratified squamous type that had a high affinity for PAS, methylene blue, and PAP stains. Ultra-structural features of the modified esophageal epithelium resembled stratified squamous epithelium and contained hypertrophic Keratinocytes; dark and light. Hypertrophic keratinocytes had RER organized, few ribosomes, and developed loose bundle of cytokeratin compared with squamous keratinocytes. Hypertrophic Keratinocytes synthesize two types of granules; peripherally located small electron-dense granules and large electron-lucent granules. Hypertrophic keratinocytes had peroxisomes that were identified by the crystalline core of the urate oxidase. In conclusion, epithelia modification may have secretory function. Further studies should be carried out to explain the exact function of this type of modified epithelium.

Histomorphology and ultrastructure of the proventriculus of the broad breasted white turkey (Meleagris gallopavo, Linnaeus 1758)

This study aims to examine the functional morphology of the proventriculus of the broad breasted white turkey (BBWT) (Meleagris gallopavo, Linnaeus 1758) using gross anatomy, light microscopy, gross/histomorphometric analysis, and scanning and transmission electron microscopy. The proventriculus was characterized internally by many elevated papillae with a mound, leafy flower, and lotus flower-shapes. Each papilla was enclosed by concentrically organized mucosal folds with distinct or indistinct proventricular gland openings on its top. Longitudinal folds and grooves at the junction of the proventriculus with the esophagus exhibited various sized and shaped openings of esophageal glands with irregular outlines. Histologically, the surface epithelium of the proventriculus was covered by a thin layer of cuticle, particularly evident at its junction with the gizzard. The lamina epithelialis and propria, and secretory units of proventricular lobules were infiltrated by aggregations of lymphocytes and lymphoid follicles (nodules). Variably shaped glandular lobules of proventricular glands occupied the submucosa, surrounded by thin strands of smooth muscle fibers derived from muscularis mucosa. Triangular, cuboidal, or columnar-shaped secretory oxyntico-peptic cells lined the secretory units. Many telocytes (pyramidal or fusiform-shaped cell bodies with lengthy telopodes) were observed in interstitial tissue. Further, two types of argyrophilic endocrine cells were identified within the glandular epithelium. The morphology of the M. gallopavo proventriculus reflects its dietary habits and behavior.

Tracking the developmental events in the duodenum of the quail embryo: Using light and electron microscope

The present study described the full morphology of the duodenum of the Japanese quail during the embryonic stage from 3rd day of incubation till hatching using the light and electron (scanning and transmission) microscope. The specimens were collected, analyzed and described anatomically, morphometrically and microscopically. The first recognition of the prospective duodenum was at the 4th day of incubation and developed continuously by age progression. The prospective duodenum consisted of a flat pseudostratified epithelium, mesenchyme and covering mesothelium. On day 8th of incubation, the epithelium developed three evaginations lead to formation three previllous ridges protruding inside the duodenal lumen, which later at the 9th day differentiated into numbers of projections; villi. On the 9th day, the epithelium lined the villi transformed into a simple columnar type, the duodenal villi appeared as pyramidal-shaped projections, had wide base and narrow apex and by age progression, the duodenal villi went through changes in number, size and shape. On hatching day, the duodenal epithelium consisted of enterocytes interspersed with secretory goblet cells, which stained positive for both Periodic Acid Schiff (PAS) and Alcian blue AB and represented filled with metachromatic granules. The muscular wall started as mesenchymal condensation on the 6th day then differentiated into the circular smooth muscle layer on the 9th day of incubation. Giving detailed information about the morphological development of the duodenum during the incubation period of quail embryo helps in reaching a satisfactory explanation about how the duodenum plays a vital role in digestion, absorption and immunity.

Detection of food fraud of meat products from the different brands by application of histological methods

In Sohag City, 400 samples were collected from different food markets of different meat products from two companies with high and low prices (e.g., minced meat, kofta sausage, beef burger, and luncheon meat) for determining food fraud. Light, fluorescence, and scanning electron microscopy (SEM) were used to examine the samples. "Special histochemical stains" permit the microscopic examination of different cell types, structures, and/or microorganisms. Histological examination revealed variant tissue types, besides skeletal muscles. Nuchal ligaments, bones, hyaline cartilages, white fibrocartilages, large and medium arteries, cardiac muscles, tendons, and collagenous connective tissues comprised the capsule of a parenchymatous organ. Additionally, a crystal of food additives was recognized using light microscopy and SEM. SEM allows the visualization of bacterial contamination. Using different microscopic anatomy techniques is an efficient methodology for qualitative evaluations of various meat products. No difference in quality was observed between low- and high-priced meat products.

Performance scanning electron microscopic investigations and elemental analysis of hair of the different animal species for forensic identification

Veterinary forensics have attracted less attention compared with human forensics. Animal hair morphological examination using scanning electron microscopy (SEM) and hair mineral analysis using energy-dispersive X-ray fluorescence (ED-XRF) provide reference databases for animal hair identification used in forensic investigations. This study was performed on four different animal species: large ruminants (buffalo and cattle), small ruminants (goat and sheep), carnivores (cat and dog), and equines (donkey and horse). The hair scale pattern, scale margin type, and distance between scales were identified. The hair scale pattern was imbricate in large ruminants, goat, and horse; coronal (crown-like) in carnivores and donkey; and spinous in sheep. The morphometric measurements, including cuticle layer thickness, cuticle scale height, cortex diameter, and hair shaft width were recorded. The highest cuticle thickness was found in horse, and the highest cuticle hair scale was detected in cattle. Moreover, the largest cortex diameter was measured in buffalo, whereas the smallest one was in cat. With regard the content of hair elements, some elements were specific for the hair of certain tested animals, such as bromine in sheep and magnesium and phosphorus in buffalo. In addition, vanadium and titanium were found only in cattle and dog, and the latter element was also detected in sheep. In conclusion, this study provides two techniques for animal hair identification that can be used in forensic investigations.

Scanning electron microscopy of the nasal skin in different animal species as a method for forensic identification

The current study aims to provide a new method for the identification of animal species by using the scanning electron microscopic study on the nasal skin around the nostril. The reference databases for animal identification using traditional ways (i.e., hair and bone analyses) were somewhat available. This study was conducted on the nasal skin of seven different animal species: large ruminants (Saidi buffalo and frozen Angus cattle); small ruminants (Egyptian goat and Rahmani sheep); camels (one-hump dromedary camel); equines (African domestic donkey and Arabian horse); carnivores (farm domestic cat, Egyptian Baladi dog, and red fox); swine (Danish Landrace pig); and rodents (albino rat and New Zealand white rabbit). The nasal skin was divided by grooves into different shaped raised areas in some examined animals, the mean diameter of these areas and width of the grooves of each animal species were recorded. The characteristic differential features of the nasal skin of each animal species have been documented. Few openings of the nasolabial glands were demonstrated in large ruminants and swine, which were H letter-shaped in buffaloes, oval-shaped in cattle, and whirlpool-shaped with several layers of folds on their margin in pig. Moreover, the openings of the lateral nasal glands were whirlpool, ovoid, and oval shaped in goats, sheep, and camels, respectively. In conclusion, the present study proved that the skin around the nostrils plays an important role as means of identification in forensic investigations and improves the field of veterinary forensic medicine in general, which is not well-developed in comparison with human forensics.

Characterization of the primo vascular system in rabbit vagina

The primo vascular system (PVS) is observed in different parts of the body under different physiological and disease conditions. Previously, the PVS was not observed in the vagina. The vaginal samples of this study were collected from the female genitalia of healthy New Zealand white rabbits from the animal house, Faculty of Medicine, Assiut University. The vaginal samples were fixed in Bouin's solution. The sections were stained with hematoxylin and eosin and Crossmon's trichrome. Additionally, the sections were immunohistochemically stained with neuron-specific enolase (NSE) and vascular endothelial growth factor (VEGF). A primo node was observed on the lymph vessel of the vagina and has several characteristics that resemble those of the previously discovered primo nodes. The primo node in this study was surrounded by mesothelial cells that provide positive immunoreactivity to NSE and VEGF. Sinuses of different sizes, floating cells, telocyte-like cell, and primo microcells were observed as the main constituents of the primo node. Additionally, migratory cells were detected, which passed from the primo node to the enclosing lymph vessel.

Developmental stages and growth of the proventriculus of post-hatching Muscovy duck: Light and electron microscopic study

The present study was implemented to provide comprehensive information on the developmental sequence of the proventriculus of Muscovy ducks by gross examination, macro-micrometric analysis and by using light microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). Samples from 55 healthy post-hatching Muscovy ducks of both sexes ranging from 1 to 60 days old. The proventriculus began cranially opposite to the cranial end of the liver at 1-15 days old, but in front this level at 30 and 60 days old. Morphometrically, the length of the proventriculus was increased by about four folds while weight by 19 folds at 60 days old when compared with those at one day old. Scanning electron microscopy of the proventricular lumen at one day old exhibited numerous small mostly rounded irregularly distributed openings of the glands, but uniformly distributed and surrounded by closely packed concentrically arranged mucosal folds resembling a rosette shape at the older ages. Histologically, in all studied stages, rounded, elongated oval or polymorphic shaped lobules of the proventricular glands were occupied within the muscularis mucosa. The tubuloalveolar secretory units lined with secretory (oxyntico-peptic) cells with variable shapes had secretory granules increased by the development. Numerous argyrophilic endocrine cells were demonstrated away from the glandular lumen at older ages. Transmission electron microscopy revealed that the cytoplasm of the secretory cells contained homogeneously electron-dense granules at a young age, but two types of these granules could be recognized at 60 days old. In conclusion, this study provides a wide difference in the morphometric and the structure of the proventriculus from one day to 60 days old. This difference between the examined age-stages may be related to the feeding strategy (behavior) and the functional adaptations from the young to the older ages.