The dromedary camel has a very high economic importance in the Arabic countries. Nevertheless, there is a very little background literature on the use of ultrasound (US) and computed tomography (CT) in dromedaries in comparison to other domestic and farm animal species. Therefore, the tarsal region of six cadaver limbs, obtained from three orthopedic disease free dromedary camels, was evaluated via radiography, US and CT. The limbs were frozen and sectioned transversely, sagittaly and dorsally. The anatomic structures were identified and correlated to the analogous structures on the corresponding CT slices and US images and published in two manuscripts. Radiography was performed in both standard (0º and 90º) oblique (45º and 135º) radiographic projections. The tarsus was investigated via US in four planes (dorsal, medial, lateral and plantar) and each plane was scrutinized in four levels (calcaneal tuber, tibial malleoli, base of calcaneus and proximal head of metatarsus) in both transverse and longitudinal views. Radiography provided a good representation of the bony structures and articulations with little information on the soft tissues of the tarsus and superimposition of the tarsal bones. Ultrasonography furnished adequate delineation of the peri-articular tissues of the tarsus and was limited to the bone surface. Computed tomography provided cross sectional imaging of the dromedary tarsus without bone and soft tissue overlap and allowed visualization and differentiation of tissues in almost every situation. This work was undertaken to document the normal appearance of the dromedary camel tarsus via radiography, ultrasonography, and computed tomography which may be used as a resource for interpretation of dromedary tarsal pathology using various diagnostic imaging modalities.

The one-humped or the dromedarian camel is a pseudo-ruminant mammal, well adapted to the hot and dry climates of the desert. Its ability to withstand torrid heat and extreme desiccation is of paramount importance to its survival. The studies presented in this thesis were designed to investigate and document the effect of dehydration in the presence or absence of angiotensin II (Ang II) AT1 receptor blocker (losartan) on blood constituents, electrolytes, hormones, neurotransmitters as well as liver and kidney enzymes in a subset of dehydrated camels and to compare them with hydrated camels. Additionally, we studied the response of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) and revealed for the first time the cardiac storage form of BNP in the camel heart. Dehydration induced significant increments in packed cell volume (PCV), white blood cells (WBC), gamma glutamyl-transferase (GGT), serum sodium, creatinine and urea levels, and a doubling in plasma cortisol and arginine vasopressin (AVP) levels. At the same time dehydration caused significant decrease in body weights, plasma insulin like growth factor-1 (IGF-1) and its binding protein-3 (IGFBP-3), and a 50% decrement in ANP and BNP levels. Moreover, dehydration with and without losartan resulted in significant changes in stress hormones and anti-oxidants in plasma, liver and kidney homogenates. Losartan on one hand enhanced the effect of dehydration resulting in significant increases in sodium, creatinine and urea levels. In addition losartan raised the  binding affinity of Ang II AT2 receptors in the small intestine with 8-fold and with 16-fold for liver AT1 receptors, indicating that Ang II AT1 and AT2 receptor binding sites were present in camel's small intestine while only AT1 receptor binding sites were found in the camel liver. One the other hand losartan resulted in significant decrease in body weights impaired the rise in anti-diuretic hormone and reduced aldosterone level. Finally, we showed that the proBNP is the storage form of BNP in the camel heart.