Khaled Aly

Development of the mesonephros in camel (Camelus dromedarius).

The study of the development of the mesonephros in the camel (Camelus dromedarius) was carried out on 16 embryos ranging from 0.9 to 8.6 cm crown vertebral rump length (CVRL). At 0.9 cm CVRL, the mesonephros is represented by a narrow strip along the roof of the thoracolumbar part of the vertebral column. At 1.4 cm CVRL, some of the mesonephric tubules are canalized but others are still solid. The mesonephric corpuscles are well developed at 1.9 cm CVRL and occupy almost the entire abdominal cavity in between the liver and the gut. Histologically, the glomeruli occupy the ventromedial aspect of the mesonephros while the mesonephric tubules become numerous, larger and more coiled. At 3 cm CVRL, the metanephros is invaginated in the caudal pole of the mesonephros, and the mesonephric tubules in some areas are differentiated into secretory and collecting tubules. At 3.5 cm CVRL the mesonephros is related dorsally to the postcardinal vein and ventrally to the subcardinal vein. At 4.7 cm CVRL continuous regression of the mesonephros from cranialwards to caudalwards is observed. At 5.3–5.5 cm CVRL, the cranial part of the mesonephros is divided into medial and lateral regions, and later the medial region completely disappears and is replaced by the primordium of the adrenal gland. At 8.6 cm CVRL, the caudal part of the mesonephros completely disappears.

Early Embryonic Development of the Camel Lumbar Spinal Cord Segment

The lumbar spinal cord segment of the one‐humped camel (Camelus dromedarius) embryos at 2.4‐ to 28‐cm crown vertebral rump length (CVRL) was examined. Major changes are occurring in the organization of the lumbar spinal cord segment at this early developmental period. At first, the spinal cord is flattened from side to side but with increase in gestational age it becomes flattened dorsoventrally. The size and shape of the lumen changes in indifferent stage of development. These changes may be in relation to the decrease of ependymal layer and increase of the mantel layer during the developmental stages. The lumen of the spinal cord is a wide spindle in shape at 2.4‐cm CVRL, diamond in shape at 5.5‐cm CVRL and narrow oval in shape at 28‐cm CVRL. It occupies about the whole, half and one‐seventh of the total height of the spinal cord at 2.4‐, 5.5‐ and 28‐cm CVRL, respectively. At the 2.4–2.7 CVRL, the spinal cord is formed of six plates: roof, floor, two alar and two basal plates. The present investigation indicates that the distribution of the ependymal, mantle and marginal layers differs in the various developmental stages of the camel embryos. The majority of the cross section of the spinal cord consists at first of ependymal and mantle layers, and a thin outer rim of the marginal layer. With the advancement of age, the ependymal layer diminishes in size, while the mantle and marginal layers increase in size forming the future grey and white matters, respectively.

Histomorphometric analysis of the irides of dogs, camels, buffalos and donkeys.

The present study was carried out to investigate the morphological and histomorphometrical characters of irides in dogs, camels, buffalos, and donkeys. The findings of the study revealed that, morphologically, the irides were consisted of an anterior border layer, a middle layer of connective tissue stroma and a posterior layer of pigmented epithelium. Interestingly, the anterior borders of all investigated animals were not enveloped by a distinct epithelial or endothelial lining, but on contrary, the posterior border was covered by pigmented epithelium. The constrictor and dilator iridial muscles were well developed in dogs, weakly developed in donkeys, and with an intermediate position in camels and buffalos. Morphometric analysis revealed significant species differences in the mean total thickness of the iris and its different layers. In addition significant differences were also found between the ratio of the means of different layers to the total thickness of the iris at the pupillary, middle and ciliary borders. In conclusion, these variations might be related to the different lifestyles and visual behaviour of the investigated animals.

Histomorphometric analysis of the choroid of donkeys, buffalos, camels and dogs

AimThe present study was carried out to investigate the morphological and histomorphometric characters of choroid in donkeys, buffalos, camels and dogs.Results The findings of the study revealed that, macroscopically, the choroid was consisted of two areas in all studied animals, except in camel which consists of one area. Histologically, the choroid consists of five layers. Interestingly, the anterior borders of all investigated animals were free of pigments except in camel. Morphometric analysis revealed significant species differences in the mean total thickness of the choroid and its different layers. In addition, significant differences were also found between the ratios of the means of different layers to the total thickness of the choroid.Conclusion In conclusion, these variations might be related to the different lifestyles and visual behavior of the investigated animals.

Scanning electron microscopy in different techniques of microvascular anastomoses: categorization and factors affecting. A descriptive work

Many researchers have investigated microvascular anastomoses by scanning electron microscope (SEM); however, there are neither reports on classifying these anastomotic types according to the SEM results nor about studying the factors that affect these results. Sixty rat femoral arteries were anastomosed using four different techniques: simple interrupted, continuous, sleeve, and autogenous arterial cuff. The anastomotic sites of each group and other two intact femoral arteries were examined by SEM. Intimal disruption and rebuilding of the blood vessel endothelium after microvascular anastomoses depend upon anastomotic time; suture placement, either intra-luminal or extra-luminal; and mechanical factors. Accordingly, the simple interrupted suture technique has the highest degree of intimal disruption and the lowest degree of regeneration, the continuous and cuff anastomoses have better rebuilding with partial neo-endothelial coverage of the cut ends, whereas the sleeve anastomosis has the best regeneration with complete coverage of the cut ends by the new endothelial cells.