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PubMed1993

Uterine activity after ovariectomy in the camel (Camelus dromedarius): effect of exogenous administration of oestrogen and progesterone.

During oestrous cycles of the camel, spontaneous uterine contractions were correlated significantly with plasma oestradiol-17 beta concentration. Ovariectomy in the camel resulted in a decreased plasma concentration of oestradiol-17 beta (< 15 pg ml-1) and progesterone (< 0.1 ng ml-1) and caused complete cessation of uterine activity. Daily administration of oestradiol benzoate (5 mg, intramuscularly) increased the plasma concentration of oestradiol-17 beta (> 45 pg ml-1) and increased the frequency and amplitude of uterine activity. Coadministration of progesterone (100 mg, intramuscularly) increased the plasma concentration of progesterone (> 4 ng ml-1) and increased the frequency but not amplitude of uterine activity. It is suggested that uterine activity in the camel is correlated with the circulating levels of oestradiol-17 beta and progesterone.

Animals↗

PubMed1990

Influence of dehydration and watering on camel red cell size: a scanning electron microscopic study.

Three young female camels were subjected to an eleven day period of dehydration followed by a single large drink. Blood haematocrit and plasma protein concentration were monitored regularly during dehydration and for 48 h following watering. Blood samples were taken at regular intervals, before and after watering, and prepared for scanning electron microscopy (SEM) for analysis of red cell size and shape. Plasma protein concentration did not change rapidly on watering implying that the camel has homeostatic mechanisms which regulate plasma osmolarity by controlling the rate at which large volumes of water are absorbed on drinking. By SEM, camel red cells were elliptical in shape with mean surface dimensions of 6.5 microns x 4.0 microns with an estimated minimum thickness at mid point of 0.95 microns: neither their shape constant nor size changed on dehydration or watering corroborating the absence of major and rapid changes in osmolarity.

Animals↗

PubMedDate not supplied

Immunoblot evaluation of the 100 and 130 kDa antigens in camel hydatid cyst fluid for the serodiagnosis of human cystic echinococcosis in Libya.

Two high molecular weight antigens with molecular masses approximately 100 kDa and 130 kDa were identified by immunoblotting camel hydatid cyst fluid, with 94% sensitivity in sera from surgically confirmed Libyan cystic echinococcosis cases. 40% of sera from surgically confirmed alveolar echinococcosis cases cross-reacted with the 100 and 130 kDa antigens, as did 5.3% of sera from human Taenia solium cysticercosis patients. No cross-reaction occurred with sera from human schistosomiasis mansoni or onchocerciasis patients. In addition, all sera from patients with non-hydatid space-occupying lesions (i.e. simple liver cysts, kidney cysts, lung tuberculosis, pulmonary carcinoma, pulmonary empyema, and lung abscess) were seronegative against the same antigens, as were control serum samples from healthy individuals. The 100 and 130 kDa antigens were strongly recognized by sera from cystic echinococcosis patients when camel or horse hydatid cyst fluid was used in immunoblotting but were only weakly recognized if sheep or human hydatid cyst fluid was used. Camel hydatid cyst fluid could be an important source of diagnostic antigens for human cystic echinococcosis in the Middle East endemic region.

Animals↗

PubMed1989

Circulating concentrations of thyroid hormones in pregnant camels (Camelus dromedarius ).

Blood samples from 16 female camels were collected at monthly intervals commencing from 60 d post. breeding until the last month of gestation. Two camels failed to conceive and two had unnoticed abortions. The average gestation period was 398+/-13 and 372+/-11 in camels bearing male and female fetus, respectively, with an overall mean of 383+/-9 d. Sera were analyzed for thyroxine (T(4)) and triiodothyronine (T(3)) by radioimmunoassay. Mean T(4) and T(3) concentrations varied from 76 to 116 ng/ml and 0.73 to 1.32 ng/ml, respectively, during various stages of gestation. In general, the T(4) and T(3) levels were higher during early pregnancy, with lowest values in the tenth month. T(4):T(3) ratio showed minor, nonsignificant fluctuations. Age of dam of sex of fetus had no effect on hormone levels. Similarly, hormone levels were not affected by failure of conception or by abortion.

Journal Article↗

PubMed1995

Studies on the haemolytic complement of the dromedary camel (Camelus dromedarius). I. Classical pathway haemolytic activity in serum.

Classical pathway haemolytic complement (CPHC) of the dromedary was assayed under standardised conditions. A total of 14 indicator systems of red blood cells (RBC) and haemolysins were investigated. Highest CH50 titre was obtained with rabbit RBC sensitised with goat haemolysin. Among the factors investigated were: ionic strength, Mg2+, Ca2+, ethylenediaminetetraacetic acid (EDTA) concentration, pH, incubation time and temperature. The standard system of titrating the HC levels consisted of rabbit RBC sensitised with goat haemolysin, sucrose veronal buffer (SVBS) pH 7.4, ionic strength 0.14 M and Ca2+ and Mg2+ concentrations of 4.0 x 10(-4) M and 1 x 10(-3) M, respectively. Incubation at 37 degrees C for 120 min gave the highest HC activity. Using these standardised conditions HC levels were determined in 79 camels aged between 3 months and 15 years. Highest mean HC value of 873 +/- 26.6 CH50 units ml-1 were recorded in the age group of 1-5 year old camels and the lowest mean HC value of 598 +/- 120.8 CH50 units ml-1 in the age group of 10-15 year old camels. Adult males in the age group 5-10 years had significantly higher mean HC levels than their female counterparts (P < 0.0001).

Animals↗

PubMed1984

Camels' milk: for drinking only?

Camels' milk, women's milk and cows' milk were kept at 30 degrees C and refrigerated at 4 degrees C. This explains the necessity to immediately freeze milk if it needs to be kept even for a few days. Cows' milk remained good for days if stirred and then turned sour, enabling the making of cheeses and butter. Camels' milk did not sour at 4 degrees C for up to 3 months. This means that camels' milk is mainly good only for drinking, as was promised to this animal by the Prophet.

Animals↗

PubMed1985

A comparative study of serum and organ alpha-amylases of the camel (Camelus dromedarius).

The activity of alpha-amylase of the camel serum was found to be remarkably high (2325 U/l as compared with 77 U/l of bovine serum). The results obtained on chloride activation and substrate affinity studies as well as the DEAE-cellulose absorption properties indicate a substantial similarity between serum and tissue amylase(s) of the camel. On the contrary, a marked difference between the camel and the bovine amylases has been evidenced.

Animals↗

PubMed1989

Liver function and protein binding in camels.

1. Dehydration of camels for 10 days resulted in reduction of liver functions, expressed in longer half life and reduced clearance of bromosulfophthalein (BSP), elevated AST (ALT levels were below the limit of detection of the method) and reduced serum albumin concentrations. 2. Binding of BSP to camel serum proteins by gel permeation chromatography and by equilibrium dialysis showed very strong binding. 3. Binding parameters of various drugs to camels serum by equilibrium dialysis showed close similarities both qualitatively and quantitatively to those of humans. 4. Albumin seems to be the major serum binding protein of BSP.

Alanine Transaminase↗

PubMed1992

Selective brain cooling in desert animals: the camel (Camelus dromedarius).

1. Animals living in the Arabian desert are subjected to extremely high temperatures during the day in summer and very cold nights in winter. They have developed various adaptive mechanisms in order to cope with these severe heat conditions. 2. The camel (Camelus dromedarius), like many other land animals, resorts to selective brain cooling when it is subjected to heat stress. 3. This mechanism protects the heat-sensitive brain tissue from heat stress and at the same time increases the animals' tolerance to high temperatures. 4. The blood cooled in the nasal cavity by evaporative heat loss is diverted to the brain sinuses via the nasal and angular veins. 5. In the cavernous sinus, the arterial blood in the carotid rete is cooled by the cold venous blood before entering the brain. This will lead to significant cooling of the brain tissue. 6. Active myogenic tone was mainly observed in the facial, nasal and angular oculi veins of the camels head. This tone was found to be sensitive to small changes in temperature in the range 33-45 degrees C. 7. The facial veins constricted, while the nasal and angular oculi veins relaxed to increasing temperatures. This leads to a coursing of cold venous return to the brain's sinuses for selective brain cooling. 8. It is concluded that this myogenic vasoactive mechanism is a major factor in the control of blood flow in the facial area of the camel during heat stress.

Animals↗

PubMed1988

Prevalence of toxoplasmosis in Saudi Arabian camels (Camelus dromedarius).

Serum samples from 227 Saudi Arabian camels were examined for Toxoplasma gondii antibodies by the indirect haemagglutination test, using a microtitre technique. Agglutinations (greater than 2+) occurring at 1:64 dilution were considered positive. A total of 36 (16%) camels were serologically positive for toxoplasmosis, giving titres ranging between 1:64 and 1:8192. The prevalence was much higher in female compared to male camels and in adults compared to young individuals.

Animals↗

PubMed1987

The purification, characterization and regulatory properties of liver phosphofructokinase in the Arabian one-humped camel (Camelus dromedarius).

1. Phosphofructokinase from camel liver was purified to homogeneity more than 3600-fold, and the yield of the preparation was 46%. 2. The sodium dodecyl sulphate-treated purified enzyme migrated as a single band in 10% polyacrylamide gel. 3. The enzyme is a tetramer, with a monomer Mr 90,000. 4. The regulatory properties of the purified enzyme from camel liver were studied at pH 7.0. 5. The enzyme displayed cooperativity with respect to fructose 6-phosphate and was inhibited by high concentrations of ATP. 6. The enzyme was also inhibited by citrate, phosphocreatine and 2,3-bisphosphoglycerate. 7. On the other hand, ADP, AMP, glucose 1,6-bisphosphate and fructose 2,6-bisphosphate were all found to be strong activators for camel liver phosphofructokinase.

2,3-Diphosphoglycerate↗

PubMed1987

Levels of glycosylated haemoglobin in the Arabian camel (Camelus dromedarius).

Proportions of glycosylated haemoglobin (Hb) were determined in 10 Arabian camels (Camelus dromedarius) and were compared with normal controls (n = 59) and diabetic patients (n = 47) using the thiobarbituric acid (TBA) method. The level of glycosylated haemoglobin (5.5%) in camels is significantly different from that of normal healthy humans (4.9%) (P less than 0.001). Whereas the glucose levels were comparable, this difference in percentages of glycosylated haemoglobin may be explained by the difference in survival time between human and camel red blood cells.

Animals↗

PubMed1996

The inhibitory effect of cyclophosphamide on camel retina acetylcholinesterase activity.

Kinetic parameters for the effect of cyclophosphamide (CP) on the camel retina acetylcholinesterase (AChE) activity were investigated for the first time in the present study. It was found that 18 micrograms of retina protein and an incubation time of 4.0 min were suitable conditions for linear of AChE activity. The CP effect was independent of time of incubation with AChE before the addition of substrate, which shows it reversible action. Moreover, dilution data prove that CP is a reversible inhibitor of camel retina AChE. Cyclophosphamide (0.2-2.4 mM) inhibited activity of camel retina in a concentration-dependent fashion, the IC50 being about 1.17 mM. The Michaelis constant (K(m)) for the hydrolysis of acetylthiocholine iodide was found to be 0.106 mM and the Vmax was 0.765 mumol/min/mg protein. Dixon as well as Lineweaver-Burk plots and their secondary replots indicated that the nature of the inhibition was of the pure noncompetitive type. The value of Ki was estimated as 0.763 mM by the primary Dixon and secondary replots of the Lineweaver-Burk plot.

Animals↗

PubMed1993

A comparative study of liver mixed function oxidases in camels (Camelus dromedarius), guinea pigs (Cavia porcellus) and rats (Rattus norvegicus).

1. The activities of the drug-metabolizing enzymes, benzphetamine N-demethylase, 7-ethoxycoumarin O-deethylase and dicoumarol oxidation have been measured in vitro in the liver of camels, guinea pigs and rats. 2. In these species, levels of hepatic microsomal parameters namely microsomal protein, cytochrome P450, cytochrome b5 and NADPH-cytochrome c reductase have also been determined. 3. In general, camels seemed to have the lowest enzyme activity when compared to rats and guinea pigs. 4. Some sex differences were observed in the levels of enzymes studied. In rats and guinea pigs, males had higher benzphetamine N-demethylase than females. However, in camels and guinea pigs, females had higher 7-ethoxycoumarin O-deethylase when compared to males.

7-Alkoxycoumarin O-Dealkylase↗

PubMed1988

Interaction of organic azides with purified camel glutathione S-transferase.

A series of organic azides was synthesized and was tested as inhibitors of purified camel glutathione S-transferases. Enzymes purified from camel liver, lung, and kidney were inhibited reversibly by these compounds in a concentration-dependent pattern. The liver glutathione S-transferase was more sensitive to inhibition by most of these compounds and the lung enzyme was the least affected. The most effective reversible inhibitors of the tested organic azides for the purified camel liver enzyme were alkyl and allyl azides. The inhibition occurred immediately upon adding the inhibitors and remained constant during a further 30-min incubation period. The tested organic azides were found to inhibit the glutathione S-transferase catalyzed conjugation of glutathione with both 1-chloro-2,4-dinitrobenzene and 4-nitrobenzyl chloride and the kinetics of these inhibitions was qualitatively different, being competitive with some inhibitors and noncompetitive with others.

Animals↗

PubMed1996

Kinetic properties of camel lens zeta-crystallin.

Camel lens zeta-crystallin is an NADPH:quinone oxidoreductase, showing limited quinone substrate specificity: among the quinones tested, the orthoquinones were the best substrates. The kinetic mechanism of NADPH:quinone oxidoreductase activity of zeta-crystallin was investigated by steady-state initial velocity and product-inhibition studies. The results were consistent with the enzyme having a ping-pong mechanism and the intrinsic K(m) values for NADPH and 9,10-phenanthrenequinone (PQ) were estimated to be 48.0 +/- 2.5 and 36.0 +/- 1.5 microM, respectively. NADP+ showed a mixed type of inhibition with respect to NADPH, while it was a competitive inhibitor with respect to PQ. Dithiothreitol (DTT) was a strong competitive inhibitor with respect to PQ with a Ki value of 50 microM. Similarly, 2, 3-dimercaptopropanol inhibited the enzyme activity with a Ki value of 260 microM. The enzyme was inactivated by sulfhydryl groups, modifying agents such as 5,5'-dithiobis 2-nitrobenzoic acid (DTNB) and N-ethyl-maleimide. The substrate specificities and kinetic properties of camel lens NADPH:quinone oxidoreductase reported here distinguish it from previously characterized quinone oxidoreductases. This paper reports, for the first time, on the kinetic mechanism of camel lens zeta-crystallin.

Animals↗

PubMed2006

Heterogeneous nuclear-transferred-embryos reconstructed with camel (Camelus bactrianus) skin fibroblasts and enucleated ovine oocytes and their development H-M.

This study reconstructed heterogeneous embryos using camel skin fibroblast cells as donor karyoplasts and ovine oocytes as recipient cytoplasts for investigating the developmental potential of the reconstructed embryos. Serum-starved adult camel skin fibroblast cells were used as donor somatic cells. Ovine oocytes matured in vitro were employed as recipient cytoplasts. The fusion of fibroblast cells into recipient cytoplasm was induced by electrofusion. The fused oocytes were activated by 5mM/ml inomycin with 2mM/ml 6-dimethylaminopurine (6-DMAP). The activated reconstructed embryos were co-cultured with ovine cumulus cells in synthetic oviduct fluid supplemented with amino acid (SOFaa) and 10% fetal calf serum (FCS) for 168h. A total of 300 enucleated ovine oocytes were available for xenonuclear embryo reconstruction. The results showed that 71% of the nuclear transfer couplets were successfully fused, 55% of the fused oocytes cleaved within 48h after activation, 82% of the cleaved oocytes developed to 2-16-cell embryo stages and 18% of the cleaved nuclear transfer zygotes developed to the morula stage. This study demonstrated that the xenonuclear transfer camel embryos can undergo the first embryonic division and subsequent development to morula stage in vitro.

Animals↗

PubMed2006

Feed intake, forestomach fluid volume, dilution rate and mean retention of fluid in the forestomach during water deprivation and rehydration in camels (Camelus sp.).

Camels were deprived of water for 11 days. Before and during water deprivation and during rehydration changes in body weight, feed and water intake were measured. Using the liquid marker Cr-EDTA forestomach fluid volume, mean fluid retention and fluid dilution in the forestomach were estimated. At the eleventh day of water deprivation hay intake had decreased to only 9.6% of controls, dilution rates had decreased to 31%, mean retention time of fluid in the forestomach had increased to 189%. At the end of dehydration flow of saliva of 2 l/h mainly contributed to the still rather high dilution rates. Thereby buffering capacity and flow of fluid into the forestomach for microbial digestion as well as the outflow from the forestomach were maintained. At the beginning of rehydration camels drank 97 l within a few minutes, and animals thereby replaced all the water lost. Following this first huge water intake water is rapidly absorbed from the forestomach, and forestomach volume decreased again to dehydration values. At the third day of rehydration control values were reached again. Although feed intake decreased dramatically during water deprivation, functions of the forestomach can be maintained sufficiently mainly due to saliva inflow. This explains the mostly rapid recovery of camels when water is available again.

Animals↗