Rasha E. Abo-Eleneen

The development of sensorimotor reflexes in albino mice; albino rats and black-hooded rats

The present investigation aimed to show the differences in the development of sensorimotor reflexes and their relationship to the structural changes in spinal cord, cerebellum and cerebral cortex in three rodent species. The three species are albino rats (A‐Rats), black‐hooded rats (B‐Rats) and albino mice. The development of selected reflexes was examined from day (D1) to D21. The structural changes were investigated at D7, D14, and D21. The following reflexes were analyzed: fore‐limb/hind‐limb grasp, surface body righting, fore‐limb hopping, chin tactile placing, visual placing and body righting in the air. The developmental pattern of the reflexes was different in three rodent species. Although the black‐hooded rats and albino rats belong to the same species, they are different in their appearance and developmental pattern. The development of external features and sensorimotor reflexes appeared earlier in mice than in A‐Rats and B‐Rats. At D7, differentiation of neurons was observed in the spinal cord while in cerebellum and cerebrum the neurons were found to be undifferentiated. At D14 and D21, the differentiated neurons were observed in spinal cord, cerebellum and cerebrum. Our data indicate that the developmental pattern of the reflexes in rodents may not be species specific but may be related to the animal strain.

Protective Effect of Parsley Juice (Petroselinum crispum, Apiaceae) against Cadmium Deleterious Changes in the Developed Albino Mice Newborns (Mus musculus) Brain.

Parsley was used as a probe of the current experiment to prevent the behavioral, morphological and biochemical changes in the newborn brain following the administration of cadmium (Cd) to the pregnant mice. The nonanesthetized pregnant mice were given daily parsley juice (Petroselinum crispum) at doses of 20 mg/kg and 10 mg/kg. Pregnant mothers were given Cd at a dose of 30 mg/kg divided into 3 equal times. The newborns have been divided into 6 groups: Group A, mothers did not take treatment; Groups B and C, mothers were treated with low and high dose of parsley, respectively; Group D, mothers were treated only with Cd (perinatal intoxication); Groups E and F, mothers were treated with Cd doses and protected by low and high doses of parsley, respectively. Light microscopy showed that Cd-induced neuronal degeneration by chromatolysis and pyknosis in the brain regions. The low dose of parsley 10 g/kg/day exhibited significant effects in neutralizing and reducing the deleterious changes due to Cd exposure during pregnancy on the behavioral activities, neurotransmitters, oxidative stress, and brain neurons morphology of the mice newborns.

Histology of the Skin of Three Limbless Squamates Dwelling in Mesic and Arid Environments

The skin of limbless squamates has an increased contact with the substrate compared with limbed counterparts. Comparatively, the contact with the substrate is intensified in fossorial species, where the whole circumference of the body interacts with the soil during underground locomotion. Although fossoriality in Squamata, specifically lizards and snakes, has been studied ecologically and morphologically (e.g., osteological changes), not enough detail is yet available regarding changes in organs critical for underground lifestyle such as the skin. Here we used histological and microscopical techniques (scanning electron microscopy and transmission electron microscopy) to uncover the structural detail of the epidermis and dermis in three limbless reptiles, the amphisbaenian Diplometopon zarudnyi, and two snakes, Indotyphlops braminus (Typhlopidae) and Cerastes cerastes (Viperidae). The skin of these taxa shows pronounced morphological diversity, which is likely associated to different environmental and functional demands upon these reptiles. Anat Rec, 299:979–989, 2016.

Comparative histological, histochemical and ultrastructural studies of the nephron of selected snakes from the Egyptian area

The present study was aimed to compare and contrast the histochemical, histological and ultrastructural variations (microanatomical differences) in the nephrons of selected snake species, Eryx jaculus (Boidae), Psammophis sibilans (Colubridae), Naja haje (Elapidae) and Echis pyramidum (Viperidae) from Egypt. The structural studies were carried out by conventional light and electron microscopy. The nephron, the renal unit of snakes, consists of renal corpuscle, proximal tubule, intermediate segment, distal tubule and collecting tubule. The renal corpuscles have large capillaries with clear and dark fenestrated endothelial cells. The proximal tubule showed long microvilli, cytoplasmic vacuoles, developed endoplasmic reticulum and abundant mitochondria. The intermediate segment was lined by ciliated cells. The lining cells of the distal tubules showed few microvilli, abundant dense mitochondria and clear vesicles of mucous appeared in the terminal portion. The collecting tubules consisted of mucous cells. In summary, the ultra-structure studies of nephrons revealed several interspecies similarities and also some intra-species differences in species of snakes.

Anatomical study of the skull of amphisbaenian Diplometopon zarudnyi (Squamata, Amphisbaenia)

This study investigates the amphisbaenian species skull which includes cranium, lower jaw and hyoid apparatus. The medial dorsal bones comprise the premaxilla, nasal, frontal and parietal. The premaxilla carries a large medial tooth and two lateral ones. The nasals are paired bones and separated by longitudinal suture. Bones of circumorbital series are frontal, orbitosphenoid and maxilla. The occipital ring consists of basioccipital, supraoccipital and exooccipital. Supraoccipital and basioccipital are single bones while the exo-occipitals are paired. The bones of the palate comprise premaxilla, maxilla, septomaxilla, palatine, pterygoid, ectopterygoid, basisphenoid, parasphenoid, orbitosphenoid and laterosphenoid. Prevomer and pterygoid teeth are absent. Palatine represent by two separate bones. The temporal bones are clearly visible. The lower jaw consists of the dentary, articular, coronoid, supra-angular, angular and splenial. The hyoid apparatus is represented by a Y-shaped structure. The mandible is long and is suspended from the braincase via relatively short quadrate. There is an extensive contact between the long angular and the large triangular coronoid. Thus inter-mandibular joint is bridged completely by the angular and consequently, the lower jaws are relatively rigid and kinetic. The maxillae are suspended from the braincase largely by ligaments and muscles rather than through bony articulation. In conclusion, the skull shape affects feeding strategy in Diplometopon zarudnyi. The prey is ingested and transported via a rapid maxillary raking mechanism.

Microstructure of scales in selected lizard species

In the present study, it was hypothesized that micromorphology of the surface of many lizard scales appears to mimic the topography of the habitat in which they live. Many authors have suggested that the microstructure of the superficial surface of scales have undergone important adaptations and have functional value in lizards. In this study, we investigated the variation and adaptation of the micromorphology and microstructure of the superficial surface of the dorsal and ventral scales from the mid-body region of Stellagama stellio (Agamidae), Stenodactylus petrii (Gekkonidae), Acanthodactylus boskianus (Lacertidae), Eumeces schneideri (Scincidae), Trachylepis quinquetaeniata (Scincidae), Scincus scincus (Scincidae), Varanus griseus (Varanidae), Chameleo chameleon (Chamaeleonidae). Skin specimens were prepared and analyzed using scanning electron microscopy. The dorsal and ventral scale surfaces had microstructure in the studied species and they exhibited unique patterns that somewhat resembled the topography of the microhabitats in which they lived. Similarity was detected in the three most related species, those having a common family, Scincidae. Ecomorphological relationships were detected between the dorsal and ventral scale microstructures and microhabitats. We conclude that environmental factors have observable influences on the microstructure of lizard scales.

Ultrastructural Study of the Alimentary Tract of Two Reptilian Species the Lizard Scincus scincus and the Snake Natrix tessellata

The ultrastructural difference of the alimentary tract of the insectivore, Scincus scincus and the carnivore, Natrix tesstellata was described by using scanning and transmission electron microscopy. The oesophagus of S. scincus with many prominent longitudinal folds while in N. tessellata it has many primary longitudinal folds and secondary ramification. The oesophageal epithelium of both species has numerous goblet cells. The mucosal epithelial cells in both species contain large nucleus, endoplasmic reticulum, lysosomes and some vacuoles. Stomach had a meshwork of primary folds in S. scincus and it forms various folds forming many discrete, irregular pockets in N. tessellata. The mucosal cells in the stomach of S. scincus have many secretory granules while in N. tessellate it provided with numerous mucinogen granules in the gastric columnar cells. In S. scincus, the intestinal mucosa with many primary folds but it appeared as longitudinal secondary mucosal folds in Zig-Zag pattern enclosing a number of concavities in N. tessellata. The intestinal mucosal cells in both species consisted of regularly formed microvilli. There were numerous goblet cells in the intestine of both species. In conclusion, structural variation of the alimentary tract in the two species examined was related to difference in feeding habits.