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PubMedDate not supplied

The prevalence of Salmonella infections in camels (Camelus dromedarius) in the United Arab Emirates.

One hundred and eighty-seven salmonella strains were isolated from 4006 samples collected from camels in the United Arab Emirates between 1987 and 1991. One hundred and sixty-five (4.3%) strains were isolated from 3801 faecal and 22 from 205 organ samples of 62 autopsied camels. In total, 28 different serotypes were identified with S. saintpaul being the most frequent (69), followed by S. frintrop (31) and S. hindmarsh (15). Salmonella typhimurium was isolated from only two faecal specimens. All salmonellas isolated from faecal samples originated from carrier camels, and those isolated from organs were secondary findings. The camels from which salmonella organisms were found died from diseases other than salmonellosis. Most of the S. saintpaul isolates originated from one herd suffering from Clostridium perfringens type A enterotoxaemia which suggests that salmonella infections may predispose camels to clostridial enterotoxaemias.

Animals↗
PubMed1983

Testicular steroidogenesis in the camel (Camelus dromedarius) during the mating and the nonmating seasons.

Enzyme reactions in the camel testis involved in androgen synthesis were studied to determine the factors which account for the low testosterone production during the non-mating season (NMS). Testes excised during the NMS were found to have a relatively high activity of the 3 beta-hydroxysteroid dehydrogenase systems of pregnenolone, 17 alpha-hydroxypregnenolone, and dehydroepiandrosterone, but the 4-ene-17 alpha-hydroxylase and 4-ene-17,20-lyase systems were apparently less active than the 5-ene-17 alpha-hydroxylase and 5-ene-17,20-lyase. On the other hand, testes excised during the mating season (MS) were found to have a relatively high activity of 4-ene-17 alpha-hydroxylase, 4-ene-lyase, and 17 beta-hydroxysteroid oxidoreductase. The 19-hydroxylation and aromatizing activities for testosterone and androstenedione were not detected in testes excised in either season. It is proposed that during the NMS the predominant route of testosterone biosynthesis is pregnenolone leads to 17 alpha-hydroxypregnenolone leads to dehydroepiandrosterone leads to androst-5-en-3 beta, 17 beta-diol leads to testosterone.

17-alpha-Hydroxypregnenolone↗
PubMed1984

Estradiol concentration in the serum of the one-humped camel (Camelus dromedarius) during the various reproductive stages.

During the estrous cycle of the camel the concentration of estradiol (E2) varies between 9 and 110 pg/ml. In early estrus, the peak level of E2 (74.7 +/- 6.61 pg/ml, n = 11) is maintained for 2.9 +/- 1.83 days. The length of an estrous cycle is 17.2 days. In the 10th month of pregnancy the level of E2 rises abruptly to 338.3 +/- 162.42 pg/ml and continues to rise until the 12th month, peaking at 606 +/- 120.27 pg/ml. The hormone concentration then drops until the day of parturition (mean 113.4 +/- 26.51 pg/ml). The level of E2 during the nonbreeding season (May-November) is low (6-48 pg/ml).

Animals↗
PubMed1984

Leydig cell differentiation during the reproductive cycle of the seasonal breeder Camelus dromedarius: an ultrastructural analysis.

Spermatogenesis and Leydig cell development in the dromedary were analyzed at the ultrastructural level and correlated with fluctuations of testosterone synthesis during the mating and nonmating seasons. It was found that (1) spermatogenesis and diameter of the seminiferous tubules are dissociated from seasonal fluctuations of testosterone synthesis as they remain similar throughout the year; (2) the volume of the interstitial tissue and the rate of testosterone synthesis are correlated since both increase during the mating season and both diminish during the nonmating season; (3) during the mating season, reduction of the tubular smooth endoplasmic reticulum (SER) and proliferation of condensed SER correspond to the relatively high rate of testosterone synthesis by the 4-ene pathway; (4) during the mating season there is a drastic reduction of the SER and proliferation of myelin figures within the Leydig cells which disrupt at the end of their differentiation. During the nonmating season, testosterone synthesis is probably impaired only at the final stage of differentiation of the Leydig cell.

Animals↗
PubMed1985

Evidence for somatostatin-like immunoreactivity in discrete cells of the anterior pituitary of camel (Camelus dromedarius).

Immunocytochemical methods were applied to camel pituitaries. ACTH, beta-lipotropin (LPH), LH beta, GH, TSH, and PRL immunoreactive cells were identified. They were located on different parts of anterior pituitary and had different organization and shape. In addition, somatostatin-like immunoreactivity was seen in cells situated at the top of pituitary cleft specially in a cone-shaped extension of the intermediate lobe. The role and the eventual origin of these cells have yet to be established and their occurrence related to age and life conditions.

Animals↗
PubMed1987

Immunocytochemical evidence for vasopressin and oxytocin pathways in the hypothalamo-hypophyseal axis of the camel (Camelus dromedarius).

Immunoperoxidase staining was applied to the hypothalamus and posterior pituitary of the camel. Vasopressin and oxytocin cells and fibers were identified in different nuclei of the hypothalamus. Immunoreactive fiber tracts were followed to the median eminence and the posterior pituitary. In the median eminence, two different pathways were found for vasopressin, one passing to the posterior lobe and the other contacting capillaries of the portal system. The oxytocin antiserum stained one unique pathway in the internal zone on its way to the posterior pituitary. The two immunoreactivities were shown in the posterior lobe of the pituitary, vasopressin staining being the more intense. Relations between these data and the physiology of the camel are discussed.

Animals↗
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↗
PubMed1995

Monoclonal antibodies against camel (Camelus dromedarius) IgG, IgM and light chains.

Monoclonal antibodies specific for camel IgG and IgM heavy chains and immunoglobulin light chains were produced by a simple, time-saving and efficient method. Popliteal lymph nodes isolated 9 days after a primary foot-pad immunisation were used as the source of antibody producing hybridoma cells. Ascites was induced in mice and ascitic fluid collected. The specificity of anti-IgG and anti-IgM monoclonal antibodies was determined by enzyme-linked immunosorbent assay (ELISA) and Western blotting. Monoclonal antibodies specifically reacting to IgG1 subclasses were demonstrated; no monoclonal antibodies specific to IgG2 or IgG3 were generated. An unexpected finding was that some class-specific monoclonal antibodies were light chain, and not heavy chain, reactive.

Animals↗
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↗
PubMed1995

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

Fresh camel serum caused lysis of unsensitised red blood cells (RBC) of chicken, rabbit and guinea pig. Homologous RBC were resistant to lysis. There was only minimal lysis of goat, sheep, rat and cattle RBC. Lysis of heterologous RBC was attributed to the presence of alternate complement activity (ACP) in the serum as adsorption with respective RBC and addition of 10 mM ethylene glycol-bistetraacetate (EGTA) in the SVBS diluent did not abrogate the haemolytic activity. Guinea pig RBC were the most sensitive to lysis, giving a mean ACP activity of 41.5 +/- 1.8 CH50 units ml-1. Clotting, followed by storing of blood between 0 and 37 degrees C for 1 h did not significantly affect ACP activity. However, considerable activity was lost when blood was clotted and stored at 44 degrees C for 1 h, or when serum was kept at 4 degrees C for 24 h. Treatment with zymosan, or incubation at 56 degrees C for 30 min inhibited ACP activity. Maximum ACP activity occurred in the presence of 8 mM Mg2+ in the SVBS-EGTA diluent, at pH 7.3 and incubation time of 2 h at 37 degrees C. Levels of ACP activity were determined in 79 healthy camels of different age groups, ranging from 3 months to 15 years. Calves between 3 months and 1 year of age had higher ACP activity than camels in the age group of 5 years and above. Highest mean ACP activity of 89 +/- 7.9 CH50 units ml-1 were recorded in 1-5 year old camels (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMedDate not supplied

Purification and characterization of luteinizing hormone from the dromedary (Camelus dromedarius).

Luteinizing hormone (LH) has been purified from 150 dromedary pituitaries and its partial physicochemical, biological and immunological characterization has been achieved. Purification of the hormone was monitored by a porcine LH radioreceptor assay (RRA). In this system, the final camLH preparation exhibited an activity 0.6-fold that of highly purified porcine LH. The acid half-dissociation of camLH at equilibrium was observed at pH 4.2. A homologous camLH RRA was developed using the testicular plasma membrane fraction from prepubertal camels and radioiodinated, highly-purified camLH. Pituitary and chorionic gonadotropins (CG) from several mammalian species were compared to camLH in this system. The equine gonadotropins eLH and eCG were shown to be 6 times less potent in the camel RRA than in the porcine RRA, whereas the LH from other species exhibited similar activities in both systems. This particularity of camel LH receptors offers a new tool for the study of structural features of gonatropin interactions with their receptors.

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↗
PubMed1986

Parturition in the camel (Camelus dromedarius) and some behavioral aspects of their newborn.

Symptoms of approaching parturition and the stage of parturition were described for eight pluriparous camels. The average time for the complete process of parturition was 373.9 +/- 38.2 min. The body weights at birth of the newborn males and females were 31.3 +/- 1.69 and 24.5 +/- 2.5 kg, respectively. Standing and first suckling by the neonatal camels occurred at 68.6 +/- 6.2 and 98.6 +/- 11.3 min, respectively.

Allantoin↗
PubMed1986

Forestomach motility in the camel (Camelus dromedarius).

There is a cyclical pattern of motility in compartments 1 and 2 of the forestomach of the camel which can be categorized into A- and B-contractions. An average motility cycle is composed of 7 A- and 5 B-contractions and lasts 5 min, including a pause of 2.3 min. The glandular sacs within the caudal sac of compartment 1 contract 1.7 sec earlier than the caudal sac. The proximal part of the canal between compartment 2 and 3 contracts 1.2 sec prior to the distal part. Forestomach motility is stimulated by distention of the cranial sac of compartment 1 and inhibited by distention of the tubiform portion of compartment 3.

Animals↗
PubMed1989

Serum cortisol levels in camels (Camelus dromedarius) during the reproductive cycle.

1. Cortisol concentrations were measured in sexually mature female camels (N = 18), two newborn camels and one adult male. 2. The study revealed a significant difference in the amounts of cortisol in pluriparous mated camels (N = 7) during the breeding season before (8.0 +/- 1.3 ng/ml) and immediately after mating, 45.0 +/- 11.9 ng/ml (P less than 0.01). 3. At the start of parturition (N = 7), the maternal serum cortisol level rose suddenly from the basal value, 11.4 +/- 1.3 ng/ml, 3 days pre partum, to 45.3 +/- 5.0 ng/ml (P less than 0.005). 4. Immediately after birth, serum levels of cortisol in the newborn camels were 35.9 ng/ml and 37.0 ng/ml, respectively; in the dams, the concentrations of serum cortisol were 60.0 and 57.0 ng/ml, respectively. 5. In the female camels (N = 2) in seasonal anoestrus the amount of serum cortisol did not exceed 8 ng/ml. 6. During the breeding season the level of serum cortisol in the male was 1.15 ng/ml; 10 min post coitus the serum cortisol level rose to 9.92 ng/ml.

Anestrus↗