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PubMed1981

Desaturation of exhaled air in camels.

We have found that camels can reduce the water loss due to evaporation from the respiratory tract in two ways: (1) by decreasing the temperature of the exhaled air and (2) by removal of water vapour from this air, resulting in the exhalation of air at less than 100% relative humidity (r.h.). Camels were kept under desert conditions and deprived of drinking water. In the daytime the exhaled air was at or near body core temperature, while in the cooler night exhaled air wat at or near ambient air temperature. In the daytime the exhaled air was fully saturated, but at night its humidity might fall to approximately 75% r.h. The combination of cooling and desaturation can provide a saving of water of 60% relative to exhalation of saturated air at body temperature. The mechanism responsible for cooling of the exhaled air is a simple heat exchange between the respiratory air and the surfaces of the nasal passageways. On inhalation these surfaces are cooled by the air passing over them, and on exhalation heat from the exhaled air is given off to these cooler surfaces. The mechanism responsible for desaturation of the air appears to depend on the hygroscopic properties of the nasal surfaces when the camel is dehydrated. The surfaces give off water vapour during inhalation and take up water from the respiratory air during exhalation. We have used a simple mechanical model to demonstrate the effectiveness of this mechanism.

Air↗

PubMed1980

Blood protein polymorphism in the one-humped camel (Camelus dromedarius) in the Sudan.

The blood protein polymorphism of serum albumin, haptoglobin, transferrin, ceruloplasmin and haemoglobin have been studied in 135 samples from one-humped Arabian camel (Camelus dromedarius) of the Sudan by starch gel electrophoresis. Only the serum albumin and haptoglobin systems exhibited polymorphism with the estimated frequencies of 0.0222, 0.2227 and 0.7773 for Albv, Hp1 and Hp2 respectively. The frequency of Hp0 was 0.0325. No electrophoretic variant was observed at transferrin, ceruloplasmin and haemoglobin loci in the camel. The activity of the ceruloplasmin of the camel sera was weak.

Animals↗

PubMed1985

The primary structure of alpha-lactalbumin from camel milk.

The primary structure of camel alpha-lactalbumin was determined by analysis of the intact protein, and of CNBr fragments and enzymatic peptides from the carboxymethylated protein chain. Results show that camel alpha-lactalbumin has 123 residues and a molecular mass of 14.6 kDa. The amino acid sequence is strictly homologous to alpha-lactalbumins characterized, but also exhibits extensive differences: 39 residues differ in relation to the bovine protein and only 35 residues are conserved among hitherto known alpha-lactalbumins with characterized structures. All residues ascribed critical structural or functional roles are strictly invariant in the camel protein.

Amino Acid Sequence↗

PubMed1997

Observations on the fine structure of the liver in the camel (Camelus dromedarius).

The structure of macroscopically inconspicuous livers in 23 adult camels (Camelus dromedarius) was studied by light and transmission electron microscopy. A well-developed connective tissue characterizes the camel liver. Thick trabeculae divide the liver parenchyma into lobules. Portal tracts and central veins are surrounded by a variable amount of fibrous tissue. In the perisinusoidal space (DISSE), collagen fibres form a dense three-dimensional network around the sinusoids. A mild to moderate fatty infiltration is present in hepatocytes of all animals. In the epithelial cells of the bile ducts, small to medium sized lipid inclusions are a common feature. The ultrastructure of hepatocytes in the camel liver corresponds to that of other domestic mammalian species. The endothelial cells lining the sinusoids show a multiple fenestration and are surrounded by a discontinuous basal lamina. Fat-storing cells are numerous and contain lipid droplets varying in size, number and electron density from one cell to another.

Animals↗

PubMed2004

Histological, histochemical and immunohistochemical study of the haemal nodes of the dromedary camel.

Haemal nodes are lymphoid organs found in various mammals and some birds. The structure of haemal nodes has been described in a number of species but not yet in the camel. Therefore, haemal nodes from 10 camels were studied histologically and tested for CD3, CD22, major histocompatibility complex (MHC) class II/DR, alpha-smooth muscle actin and for the demonstration of acid and alkaline phosphatases. The haemal nodes were of spherical or kidney shape with one or two hili and had a capsule and trabeculae of connective tissue and smooth muscles. The main parenchyma was composed of a cortex and a medulla. The cortex was formed from lymphoid follicles and diffuse interfollicular lymphocytes. The medulla consisted of lymphoid cords separated by medullary sinuses. The interfollicular lymphocytes and those in the medullary cord were CD3-positive. The lymphoid follicles showed CD22-positive cells. MHC class II/DR was expressed by most cells of the parenchyma. There were also subcapsular, peritrabecular and medullary blood sinuses. Afferent and efferent lymphatics and lymphatic sinuses were also found. Acid phosphatase-positive cells were localized mainly in the marginal, the interfollicular zone and in the medullary cord. Alkaline phosphatase positivity was observed in the endothelium of the sinuses and in the lymphoid follicles. The morphology of these organs in the camel allows a classification as haemolymph nodes and suggests involvement in blood and lymph filtration.

Animals↗

PubMed2005

Anatomy of the cranioencephalic structures of the camel (Camelus dromedarius L.) by imaging techniques: a magnetic resonance imaging study.

The objective of this study was to define the anatomy of the cranioencephalic structures and associated formations in camel using magnetic resonance imaging (MRI). MR images were acquired in sagittal, transverse and oblique dorsal planes, using spin-echo techniques, a magnet of 1.5 T and a standard human body coil. MR images were compared with corresponding frozen cross-sections of the head. Different anatomic structures were identified and labelled at each level. The resulting images provided excellent soft tissue contrast and anatomic detail of the brain and associated structures of the camel head. Annotated MR images from this study are intended to be a reference for clinical imaging studies of the head of the dromedary camel.

Animals↗

PubMed1994

Evaluation of halothane as an anaesthetic in camels (Camelus dromedarius).

Halothane as an anaesthetic was evaluated in 12 adult camels, thiopentone being used as an induction agent. In six camels, clinical signs and haematological and blood biochemical changes were investigated while in other six haemodynamic, acid base and blood gas changes were monitored. The dose of thiopentone required to ensure intubation for halothane anaesthesia was 7.25 +/- 0.33 mg/kg. A modified technique of tracheal intubation was found to be safe and quick. During halothane administration all anaesthetic effects were predictable. Complete recovery occurred in 39.5 +/- 9.8 min after discontinuation of halothane administration. Halothane moderated the thiopentone-induced tachycardia. The mean arterial pressure decreased significantly. There was an increase in the arterial carbon dioxide and venous oxygen tension during halothane anaesthesia and development of hypoxaemia after its discontinuation. The alanine aminotransferase values increased during recovery, while plasma sodium, potassium and calcium decreased. Halothane appears to be safe for camels. However, to avoid hypoxaemia in the immediate post-anaesthetic period, oxygen administration should be continued.

Anesthesia, Inhalation↗

PubMed1998

Physical, biochemical and cytologic properties of blood and synovial fluid in clinically normal adult camel (Camelus dromedarius).

Forty-three adult one-humped Iranian camels (Camelus dromedarius) were studied to determine their physical, cellular and biochemical parameters of synovial fluid and blood. All the animals were clinically normal with no clinical signs of locomotion problem. Synovial fluid samples were taken from both elbow joints, and blood samples were also obtained from the jugular vein immediately prior to arthrocentesis. The synovial fluid appeared pale, creamy, and clear with no debris. No clot formation was observed at room temperature. Mucin clot test in all samples was normal. The percentage of neutrophils and eosinophils in the synovial fluid was lower than that in blood (P < 0.05). In contrast, the percentage of lymphocytes and monocytes in the synovial fluid was higher than that in blood (P < 0.05). The concentration of protein, glucose, uric acid, inorganic phosphorus, calcium, sodium, potassium, magnesium and the activities of AST, ALT, ALP, CK and LDH was higher in the serum than in the synovial fluid (P < 0.05). Nonetheless, the concentration of chloride in the synovial fluid was higher than in the serum (P < 0.05). The concentration of urea nitrogen in the synovial fluid was similar to that of the serum. Comparing the values of the synovial fluid constituents of the left and the right elbow joint showed that there was no significant difference in any of the physical, cellular and biochemical parameters. No significant difference was found in any of the cellular and biochemical parameters of male and female camels' blood except in red blood cell counts, which was lower in females than in males. Comparing the values of the synovial fluid of male and female camels showed that there was no significant difference in any of the physical, cellular and biochemical parameters.

Animals↗

PubMed1994

A slow-spreading mild form of camel pox infection.

A slow-spreading mild form of camel-pox involving range camels in the Eastern region of Saudi Arabia was described. The morbidity rate was 10% while the case fatality rate was zero per cent. Camel pox virus was isolated and identified, and the histopathological picture of the lesions was also described. The epidemiological peculiarities of the disease were discussed.

Animals↗

PubMed1992

Aspergillosis in camels affected with a specific respiratory and enteric syndrome.

During the summer of 1990 deaths, occurred in racing camels (Camelus dromedarius) associated with a specific disease syndrome. Clinical signs included pyrexia, coughing, lachrymation, oedema of the throat and submandibular region and enlargement of submandibular lymph nodes. In terminal cases nervous signs were present and sometimes there was bloody diarrhoea and vomiting. Of 480 camels at least 70 animals were affected with the disease and about 40 died. Morbidity and mortality was greater in camels recently imported. Consistent necropsy findings were extensive petechial and ecchymotic haemorrhage beneath the epicardium, endocardium and visceral pleura and in the mediastinal lymph nodes, and haemorrhagic oedema of the pharyngeal and laryngeal areas. Haemorrhages occurred more variably in abdominal organs and on the omasal and abomasal mucosa. Bronchopneumonia, omasitis and abomasitis were observed on microscopic examination, together with liver and kidney lesions of presumed toxic origin. Fungal hyphae and, occasionally, the characteristic conidial morphology of Aspergillus fumigatus were seen in sections and direct smears from lesions in the respiratory and alimentary tracts. A fumigatus was cultured from trachea, bronchi, bronchioles, lung tissue, heart blood, omasum, abomasum, ileum and submandibular lymph nodes. Whether the role of Aspergillus in the overall syndrome is primary or secondary has not been established; no other potential aetiological agent has been identified.

Animals↗

PubMed1998

Streptococcal peritonitis in a young dromedary camel.

A male dromedary camel was presented for a primary Streptococcal zooepidemicus septic peritonitis. An underlying gross lesion was not identified during abdominal exploratory surgery. The camel responded to peritoneal lavage, peritoneal drainage and systemic antibiotic therapy. Thrombophlebitis of the left jugular vein was diagnosed 14 days after surgery. The camel died of an unknown cause 24 days after surgery.

Animals↗

PubMed1977

Glucose loading and dehydration in the camel.

Five female bedouin camels were subjected to large infusions of glucose, both when water was readily available and following 10 days of water deprivation. When the camels were hydrated the extra glucose was readily given off in the urine with only a slight increase in blood levels. Following dehydration, the blood glucose levels increased greatly while the urinary excretion was limited. Dehydration led to decreased blood insulin levels, while glucose infusion led to increased levels. The data show that the acclimatization of the camel to dehydration is not only a question of long-term adaption to desert conditions but that even following acute nonphysiological stress, i.e., glucosuria, excess loss of body water was prevented.

Adaptation, Physiological↗

PubMedDate not supplied

Production of a novel camel single-domain antibody specific for the type III mutant EGFR.

Camelids have a unique immune system capable of producing single-domain heavy-chain antibodies. The antigen-specific domain of these heavy-chain IgGs (VHH) are the smallest binding units produced by the immune system. In this study, we report the isolation and characterization of several binders against the epidermal growth factor receptor (EGFR) vIII retrieved from immune library of camels (Camelus bactrianus and Camelus dromedarius). The EGFRvIII is a ligand-independent, constitutively active, mutated form of the wild-type EGFR. The expression of EGFRvIII has been demonstrated in a wide range of human malignancies, including gliomas, and breast, prostate, ovarian and lung cancer. Camels were immunized with a synthetic peptide corresponding to a mutated sequence and tissue homogenates. Single-domain antibodies (VHH) were directly selected by panning a phage display library on successively decreasing amounts of synthetic peptide immobilized on magnetic beads. The anti-EGFRvIII camel single-domain antibodies selectively bound to the EGFRvIII peptide and reacted specifically with the immunoaffinity-purified antigen from a non-small cell lung cancer patient. These antibodies with affinities in the nanomolar range recognized the EGFRvIII peptide and affinity-purified mutated receptor. We concluded that using the phage display technique, antigen-specific VHH antibody fragments are readily accessible from the camelids. These antibodies may be good candidates for tumor-diagnostic and therapeutic applications.

Animals↗

PubMed1979

Marginal bands in camel erythrocytes.

The elliptical, anucleate erythrocytes of camels have been examined for the presence of marginal bands and their constituent microtubules. Lysis of erythrocytes under microtubule-stabilizing conditions readily revealed marginal bands in at least 3 % of the cells, as observed by phase-contrast and darkfield light microscopy. Microtubules plus a marginal band-encompassing network of material are visible in lysed cell whole mounts with transmission electron microscopy. Marginal band microtubules are also evident in electron micrographs of thin-sectioned camel erythrocytes identifiable as reticuloyctes on the basis of submaximal electron density (reduced haemoglobin iron content) and presence of polysomes. The results suggest that marginal bands may be involved in morphogenesis of camel erythrocytes but are not required for maintenance of their ellipticity after cells are fully differentiated.

Animals↗

PubMed2000

Hump attachment structure of the two-humped camel (Camelus bactrianus).

The hump attachment structure was morphologically examined in the two-humped camel (Camelus bactrianus). The cranial hump is fixed by the trapezius and rhomboid muscles in the thoracic region. The strong collagen sheet in the basement of the hump is attached to the segmented bellies of the trapezius muscle, and the thoracic rhomboid muscle and the nuchal-supraspinous ligament support the attachment function of the trapezius muscle. The basement sheet possesses the line structure of collagen fibers, which are fitted to the segmented bundles of the trapezius muscle, and we observed that the muscle cells of the trapezius muscle are intermingled with the collagen fibers around the attachment line structure. In contrast, the caudal hump is directly attached to the subcutaneous tissue in the superficial region of the lumbar longissimus and lumbar iliocostal muscles. These findings demonstrated that the caudal hump of the two-humped camel is consistent with the hump of the one-humped camel in the attachment structure.

Adipose Tissue↗

PubMed2005

Molecular cloning and phylogenetic analysis of inflammatory cytokines of Camelidae (llama and camel).

We cloned, sequenced and analyzed the cDNAs encoding Camelidae inflammatory cytokines, including llama (lama glama) interleukin (IL)-1alpha, IL-1beta, IL-6, tumor necrosis factor (TNF)-alpha and camel (Camelus bactrianus) IL-6 and TNF-alpha. The similarity levels of the deduced amino acid sequences of IL-1alpha, IL-1beta, IL-6 and TNF-alpha from llama (camel) to those from other mammalian species, ranged from 60.7% to 87.7%, 52.8% to 75.3%, 41.4% to 98.6%, and 72.9% to 99.6%, respectively. Phylogenetic analyses based on nucleic acid sequences showed that llama IL-1alpha, IL-1beta, IL-6 and TNF-alpha were more closely related to those of camel, pig, cattle, sheep and horse than to those of human, dog, cat, mouse and rat.

Amino Acid Sequence↗

PubMedDate not supplied

Swelling-stimulated passive potassium transport in camel erythrocytes: inhibitory effects of furosemide and sodium fluoride.

The inhibitory effects of furosemide, sodium fluoride, and age on volume-dependent, ouabain-resistant K+ influx were investigated in camel red blood cells. Swelling of young camel erythrocytes hypotonically stimulates ouabain-resistant potassium influx, a response that was lacking in old camel erythrocytes. The swelling-stimulated influx was partially inhibited by 1 mM furosemide and by 10 and 20 mM sodium fluoride. The inhibitory effect of furosemide was significantly increased if rubidium was added to the flux media. There was a significant correlation between potassium influx in normo- and hypotonic media which might indicate that the anion-dependent transport system operates, to some extent, to regulate cell volume.

Animals↗

PubMed2003

5'-flanking regions of camel milk genes are highly similar to homologue regions of other species and can be divided into two distinct groups.

The concentrations of individual casein and whey proteins in camel milk differ markedly to respective protein concentrations in bovine milk. The ratio of beta-casein to kappa-casein is considerably higher in camel milk. beta-Lactoglobulin is absent, but whey acidic protein and peptidoglycan recognition protein have been detected. Genomic sequences upstream to milk-protein genes, which are known to regulate the expression of milk proteins to a great extent, were determined for 10 camel milk-protein genes and compared to respective sequences in other mammals. Multiple sequence alignment showed closest relationships to homologous sequences from other mammals. Comparison of milk protein regulative regions revealed two distantly related groups with pronouncedly different transcription factor site probabilities. The GC-content in sequences of the first group was considerably higher than in sequences of the second group and combined occurrence of CAAT and TATAA boxes was rare, suggesting that the first group represented mostly the housekeeping gene type, probably regulated by cellular signal transduction pathways, whereas the second group helped to regulate genes specifically expressed in terminally differentiated cells of the lactating alveolar epithelium. A core region of the composite response element, which primarily controls milk protein gene activity, was found by a search for elements conserved within all 5'-flanking sequences analyzed, and it is assumed, that the presence of this element determines gene expression in the lactating mammary gland, and binding sites for general activator and repressor factors, surrounding the milk protein gene specific element, are important for regulation of gene activity.

Animals↗