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At least 235 records · Page 13Linked to original sources

PubMed2006

Effectiveness of a tris-based extender (SHOTOR diluent) for the preservation of Bactrian camel (Camelus bactrianus) semen.

The development of a suitable semen extender is required to extend artificial breeding programs and to preserve the genetic potential of Bactrian camel. Experiments were conducted to provide the optimal osmolality and pH of tris-based extender and to compare that with available extenders for short-term preservation of Bactrian camel semen at 4 degrees C during 24 h. In experiments I and II, the effects of varying osmolalities (270, 300, 330, 360, and 390 mOsm/kg) and pHs (5.5, 6, 6.9, 7.5, 7.9, and 8.9) of tris-based extender on sperm viability were investigated. In experiment III, the efficiency of tris-based extender (SHOTOR diluent) in preserving Bactrian camel semen was compared with lactose (10%), sucrose (10%) and Green buffer. Viability parameters including progressive forward motility (PFM), plasma membrane integrity and the percentage of live spermatozoa were assessed. The data were analyzed using general linear model procedure. In the majority of assessments using tris-based extender, the viability of spermatozoa was superior at the osmolality of 330 mOsm/kg and pH of 6.9. PFM was significantly greater at the time of semen dilution in tris-based (65.5%) and Green buffer (60.5%) compared to that of lactose (31%) and sucrose (28%) extenders (P<0.05), and remained elevated throughout the experiment. There was no significant difference in other viability parameters among 4 extenders (P>0.05). In conclusion, the utilization of a tris-based extender, having the osmolality of 330 mOsm/kg and pH of 6.9, favors the short-term preservation of the Bactrian camel spermatozoa under chilled condition.

Animals↗

PubMed2004

Camelized rabbit-derived VH single-domain intrabodies against Vif strongly neutralize HIV-1 infectivity.

We recently developed a specific single-chain antibody from immunized rabbits to HIV-1 Vif protein that was expressed intracellularly and inhibited reverse transcription and viral replication. The Vif of HIV-1 overcomes the innate antiviral activity of a cytidine deaminase Apobec3G (CEM15) that induces G to A hypermutation in the viral genome, resulting in enhancement of viral replication infectivity. Here, we have developed a minimal scaffold VH fragment with intrabody properties derived from anti-Vif single-chain antibody that was engineered to mimic camelid antibody domains. Non-specific binding of VH by its interface for the light chain variable domain (VL) was prevented through amino acid mutations in framework 2 and 4 (Val37F, G44E, L45R, W47G and W103R). Our results demonstrate that all constructed anti-Vif VH single-domains preserve the antigen-binding activity and specificity in the absence of the parent VL domain. However, only the most highly camelized domains had high levels of intracellular expression. The expression in eukaryotic cells showed that VH single-domains could correctly fold as soluble proteins in the reducing environment. The results demonstrated an excellent correlation between improvements in protein solubility with gradually increasing camelization. Camelized single-domains efficiently bound Vif protein and neutralized its infectivity enhancing function, by reducing late reverse transcripts and proviral integration. The activity of the anti-Vif single-domains was shown to be cell-specific, with inhibitory effects only in cells non-permissive that require Vif for HIV-1 replication. Moreover, cell specificity of anti-Vif intrabodies was correlated with an increase of Apobec3G, which potentiates viral inhibition. The present study strongly suggests that camelization of rabbit VH domains is a potentially useful approach for engineering intrabodies for gene therapy.

Amino Acid Sequence↗

PubMed1999

Single domain antibodies: comparison of camel VH and camelised human VH domains.

The antigen binding sites of conventional antibodies are formed primarily by the hypervariable loops from both the heavy and the light chain variable domains. Functional antigen binding sites can however also be formed by heavy chain variable domains (VH) alone. In vivo, such binding sites have evolved in camels and camelids as part of antibodies, which consist only of two heavy chains and lack light chains. Analysis of the differences in amino acid sequence between the VHs of these camel heavy chain-only antibodies and VH domains from conventional human antibodies helped to design an altered human VH domain. This camelised VH proved, like the camel VH, to be a small, robust and efficient recognition unit formed by a single immunoglobulin (Ig) domain. Biochemical, structural and antigen binding characterisation properties of both camel VH domains and camelised human VH domains suggest that these can compete successfully with single chain variable domain (Fv) fragments from conventional antibodies in many applications. Of special importance in this respect is the use of such VH domains as enzyme inhibitors, for which they seem to be better suited than Fv fragments. This function appears to be closely related to their often very long third hypervariable loop, which is central for antigen recognition in their binding sites.

Amino Acid Sequence↗

PubMed1996

Mastitis in Camelus dromedarius and the somatic cell content of camels' milk.

Seven hundred and sixty-three camels from 400 herds of local Sudanese camel breeds were investigated for the prevalence of mastitis, identification of its bacterial causes and determination of the leucocyte contents of camel's milk. One hundred and forty-nine (19.5 per cent) of the 763 camels examined were diagnosed as mastitis cases based on clinical signs. One hundred and fifty-nine (47.3 per cent) of the 336 randomly selected milk samples were reactive in a rapid mastitis test and 16 of the 153 tested samples contained Brucella abortus agglutinating antibodies. Streptococcus, Staphylococcus, Micrococcus and Aerobacter species and Escherichia coli were found to be the main causes of mastitis (in descending order). The leucocyte contents of the 757 milk samples ranged from < 5 x 10(5) to > 7.5 x 10(6) leucocyte ml-1 and 42.8 per cent of the samples contained < 5 x 10(5) cells ml-1. Neither significant correlation between the leucocyte content of milk and isolated bacterial species nor significant variation in leucocyte contents during different stages of lactation were detected.

Animals↗

PubMed1996

Pattern of distribution of neuropeptides in the camel lacrimal gland.

The pattern of distribution of neuropeptides, including neuropeptide-Y (NPY), vasoactive intestinal polypeptide (VIP), neurotensin (NT), serotonin (5-HT), galanin (GAL), leucine-enkephalin (LEU-ENK) and calcitoningene-related-peptide (CGRP), in the nerves of the camel lacrimal gland was investigated using immunohistochemical techniques. Fresh lacrimal gland segments, obtained from adult camels slaughtered in the local abattoir, were used for the immunohistochemical techniques. NPY and LEU-ENK immunoreactivity was observed in the nerve cell bodies and nerve fibers of the camel lacrimal gland. VIP, GAL and CGRP were demonstrated predominantly in fine varicose nerve fibers lying on the basolateral surfaces of the lacrimal acinar cells. NT and 5-HT were identified mainly in neurons situated in the periacinar regions, close to the basal surfaces of the acinar cells. It is concluded that the camel lacrimal nerves contain several neuropeptides including NPY, VIP, NT, 5-HT, GAL, LEU-ENK and CGRP which may modulate lacrimal fluid and protein secretion.

Animals↗

PubMed2000

Immunohistology of the splenic compartments of the one humped camel (Camelus dromedarius).

The cellular composition of the different splenic compartments is well characterized in several species, but the spleen of the camel has not been studied due to the lack of specific antibodies detecting its leukocyte subsets. Therefore, 5microm frozen sections from 15 camel spleens (0.5-15 years) were studied for acid and alkaline phosphatases and for cross-reaction with antibodies specific for bovine (n=181), swine (n=14) and human (n=6) leukocyte determinants. Fifteen antibodies cross-reacted with camel spleen cells. These included 13 anti-bovine, two anti-human, but no anti-swine antibodies. The lymph follicles mainly consisted of B cells. The germinal centers showed a strong alkaline phosphatase activity. The periarterial lymphatic sheath harbored T lymphocytes. The marginal zone contained gammadelta T cells, CD45R0+, MHC class II DR+, CD44+, IL-A 24+ cells and few macrophages. The red pulp contained B, T, MHC class II DR+, IL-A24+ and gammadelta T cells and few macrophages. The periarterial macrophage sheaths contained many more macrophages than the marginal zone, so they may play a central role in the phagocytosis of the blood born particles. The alkaline phosphatase probably labeled activated B cells, but in contrast to other species no positive cells were found in the marginal zone. In general, lymphocyte compartmentalization in the camel spleen is similar to that in other species except for lower numbers of macrophages and the absence of alkaline phosphatase positive cells in the marginal zone. No age related differences were observed in the splenic compartments.

Acid Phosphatase↗

PubMed1997

Some factors affecting the prevalence of Trypanosoma evansi in camels in Mauritania.

A study was conducted on the epidemiology of camel trypanosomosis in Mauritania using 2073 camels of various ages in five regions (Trarza, Gorgol, Adrar, Hodh E1 Chargui, Nouakchott). The prevalence was determined through blood smear and serological tests: card agglutination test for trypanosomiasis (CATT) and immuno fluorescence antibody test (IFAT). The prevalence of the disease was 1.3% using blood smear examinations, 16.2% with CATT and 25.2% with IFAT. The following variations were observed: (1) Camels in Trarza had the highest prevalence; (2) Intraregion was a significant factor; (3) Animals that migrated to the south were more commonly infected than those in the north; and (4) Animals in the 5- to 10-yr age group had the highest prevalence. The study indicated that camel trypanosomosis was widespread in Mauritania, especially in the wooded areas near waterways in the south.

Age Factors↗

PubMed1997

Genital myiasis (Wohlfahrtiosis) in camel herds of Mongolia.

Genital infestations caused by Wohlfahrtia magnifica (Schiner, 1862) has been reported as being a common problem encountered in female camels in the Gobi desert. Thus, a field investigation to establish the prevalence of wohlfarthiosis in camel herds in the eastern Gobi district was carried out between May and July 1994. The objectives of the study were to establish the relevance of genital myiasis, and to describe the disease patterns, clinical course and pathomorphological changes associated with it. The field study was designed to suit the specific ecological, infrastructural and logistic conditions. Two cross-sectional samples were taken from 45 selected herds in six different areas of the Chatanbulag Sumon to obtain data on herd structure, age distribution, and the breeding history of infested female animals. Post partum events and previous occurrence of genital myiasis were recorded by use of a standardised questionnaire. Clinically infested animals were first detected visually. All camels to be investigated further were subsequently immobilised using ropes and the genitals were examined for tissue lesions and the presence of larvae. Examination of 1676 Bactrian camels from 45 selected herds in six different areas of the Chatanbulag Sumon in the Eastern Gobi district, Mongolia, led to an estimate of Wohlfahrtia magnifica infestation rates between 8-10%. Most myiasis cases were found in older females (> 4 yr), younger animals were infested at a lower rate. Highest prevalence rates were discovered during June and July, highest levels of infestation occurred in the Aman Us Chudak region with infestation rates up to 15%.

Age Factors↗

PubMed2000

Real-time ultrasonography of ovaries and breeding of the one-humped camel (Camelus dromedarius) during the early postpartum period.

Ovaries of 17 adult, pleuriparous, and lactating one-humped she-camels (Camelus dromedarius) were examined per rectum for uterine involution and for presence of follicles (>/=1.0 cm diameter) by real-time ultrasonography at the National Research Centre on Camel at Bikaner, India at 30, 45, 60, 75, and 90 days postpartum. Involution was completed from 25 to 30 days postpartum and follicles (>/=1.0 cm diameter) could be found in only nine camels (52.7%) from 34 to 70 days postpartum. These nine camels were mated with virile studs. Four conceived and were confirmed pregnant at 60 days.

Animals↗

PubMed2002

On the intrinsic innervation of the epididymis of the camel (Camelus dromedarius).

The innervation of the camel epididymis was studied in 26 apparently healthy, sexually mature animals aged between 4 and 12 years. The material was collected during the different seasons of the year. Generally, five samples were taken from each epididymis. To demonstrate the general innervation pattern, immunohistochemical reactions to protein gene product-9.5, neurofilaments and neuron-specific enolase were used, in addition to acetylcholinesterase histochemistry. The nerve supply of the epididymis comes from two sources: (1) The majority of fibers come from the N. spermaticus inferior and accompany the deferent duct. (2) Another contribution stems from the N. spermaticus superior and enters the head region of the epididymis. From the exterior, the nerves penetrate the capsule of the organ to reach the interductular connective tissue. The terminal ramifications are observed directly within the wall of the duct and the wall of the epididymal arteries. The veins of the camel epididymis are not innervated. In the wall of the ductus epididymidis, the nerve fibers form plexuses at the subepithelial level and in the muscular coat. The amount of nerve fibers increases from the head to the tail, paralleling an increase in the intrinsic musculature. The intramural and interductular innervation of epididymal body and tail shows clear seasonal variations: More fibers and stronger reactions are observed during the winter season; the lowest density and the weakest reactions occur during the summer season. All epididymal nerves of the camel are unmyelinated. The majority of the intramural fibers and all in the arterial wall represent postjunctional sympathetic axons, but in the intramural plexuses of the duct a considerable number of cholinergic fibers are also present. Neuropeptide Y is the most frequent peptidergic transmitter and generally co-localized with dopamine-beta-hydroxylase in the sympathetic axons. Vasoactive intestinal polypeptide has a distribution similar to that of the cholinergic fibers. Calcitonin gene-related peptide-positive axons occur in moderate numbers, but never in the arterial innervation. Together with the relatively rare substance P-containing fibers, the calcitonin gene-related peptide-positive axons seem to represent the only sensory nerves in the camel epididymis.

Acetylcholinesterase↗

PubMed1997

Studies on the age of puberty of male camels (Camelus dromedaries) in Saudi Arabia.

Aspects of sexual development and attainment of sexual and breeding maturity were studied in two groups of Najdi camels (Mojaheem and Wadah), maintained in stalls under good nutritional conditions. Body weight, testes diameter and degree of penile freedom were recorded weekly. Sexual maturity was assessed by the examination of semen collected by an artificial vagina. Puberty was defined as the stage when the animal was able to produce viable sperms. Mating, followed by strong jerks and ejaculation of mature sperms, was taken to indicate onset of breeding maturity. Mojaheem camels reached sexual maturity at a significantly younger age and heavier weight (164 weeks and 360 kg) than Wadah camels (182 weeks and 336.5 kg) (P < 0.001). Complete separation of the penis from preputial adhesions occurred at an average age of 138.6 weeks in both breeds. At the point of sexual maturity, the mean percentage of live spermatozoa was 65.1 +/- 5.2 while percentage of abnormal sperms was 17.6 +/- 2.2; total motility was 40 +/- 16% and progressive motility (48 +/- 2.2% (semen pH range 7.8-8.2). The percentage of live sperm was 65 +/- 1.5 (normal sperms 82 +/- 4). It is suggested that the encouragement of rapid growth during the pubertal period in camels managed under good nutritional and environmental conditions could assist early sexual development and breeding maturity.

Aging↗

PubMed1998

N-ethylmaliemide (NEM)-stimulated potassium transport in camel erythrocytes.

In this study N-ethylmaliemide (NME)-stimulated, ouabain-resistant potassium influx in camel erythrocytes was measured using the radioactive rubidium tracer 86Rb+. The results showed that camel erythrocytes responded to NEM pretreatment by a threefold increase in influx which was Cl- dependent. The anion dependence of K+ influx in pre-treated cells was Br- > Cl- > NO3-. The pH dependence curve for NEM-stimulated K+ influx and the combination between volume and NEM stimulation in camel erythrocytes were determined. The findings indicated that the camel erythrocytes potassium transport system has many similarities to that of other mammalian species.

Animals↗

PubMed1998

Prevalence and infection pattern of Trypanosoma evansi in camels in mid-eastern Sudan.

The antigen detection enzyme immunoassay (AgELISA) in conjunction with parasitological examination of blood were used to study the enzootic situation of cameline trypanosomiasis in mid-Eastern Sudan. A one year survey showed that the infection is endemic among pastoral camels with a prevalence of 5.4% based on parasitological examination and 31.3% based on AgELISA. The infection rate was higher during the dry period (November to May) than the wet season. Young camels had a much lower infection rate as detected by parasitological techniques, but not with AgELISA. A lower prevalence of infection was detected by buffy coat technique (BCT) in herds of camels raised by nomads compared with those kept by agropastoralists and in camels located in the southern districts of mid-Eastern Sudan.

Age Distribution↗

PubMed2001

Retinol values in the plasma of the Arabian camel (Camelus dromedarius) and the influence of aflatoxicosis.

The normal values are reported of the concentration of vitamin A (retinol) in the plasma of 44 male and female adult camels (Camelus dromedarius) in the United Arab Emirates. The concentrations of the vitamin in the plasma of eight camels of both sexes afflicted with aflatoxicosis were also determined. The mean concentration (+/-SD) of the vitamin in healthy camels was 460.1 +/- 49.3 ng/L. Sex had no significant effect on the concentration of the vitamin. Camels with aflatoxicosis had a mean concentration of retinol in the plasma of 243.4 +/- 32.3 ng/L. The concentrations of aflatoxins in the liver and ruminal contents of these animals were 18.2 +/- 1.3 and 243.4 microg/kg, respectively.

Aflatoxins↗

PubMed2001

Studies on Cephalopina titillator, the cause of 'Sengale' in camels (Camelus dromedarius) in semi-arid areas of Somali State, Ethiopia.

The overall prevalence rate of Cephalopina titillator in 778 slaughtered camels was 71.7%, 55% in males and 85% in females. The mean larval counts in infested camels were 26.7 +/- 25.9 and 34.6 +/- 30.8, for males and females, respectively. There were highly significant differences (p < 0.001) in the number of larvae in camels of different ages and sexes and also between the wet and dry seasons. The average time to pupate was 4.9 +/- 4.6 minutes, and the pupation period was 21 +/- 2.4 days. The major gross lesions observed were congestion of the pharyngeal mucosa with profuse secretions, and haemorrhage in early cases. In some cases, there were ulcer-like lesions and nodules, which contained pus. The dominant microscopic lesions were infiltration of the lamina propria by eosinophils, lymphocytes and macrophages, hyperplasia of the stratified squamous epithelium, necrotic changes in the mixed glands and desquamation of epithelial cells. A survey using questionnaires revealed that all the camel owners called the disease caused by infestation with C. titillator 'Sengale' and that 87% of them considered that infestation with these larvae results in reduced milk production and body weight. The major clinical signs of the disease were sneezing and expulsion of larvae (68%), abnormal movement of the head (45%), grooming (44%), nasal discharge (40%), poor appetite (26.7%), difficulty in breathing (18%), and sometimes bleeding from the nostrils (18%) and coughing (27%).

Age Factors↗

PubMed2004

The nerve supply to the orbit of the Bactrian camel.

The Bactrian camel is an important domestic animal in some desert and semi-desert areas of the world, but there is no detailed description of the nervous supply to the orbit in this animal. In this study, 10 heads of adult Bactrian camels were collected and the nerves supplying the orbit were examined grossly. The results showed that the nerves supplying the orbit included the optic nerve, oculomotor nerve, trochlear nerve, abducent nerve, the branches of ophthalmic nerve and the maxillary nerve. The anatomical characteristics of the origins, courses and distributions of the nerves to the orbit in the Bactrian camel were described and compared with those of other domestic animals. These results have importance for further research on the comparative neuroanatomy, neurophysiology and the related clinical surgery of the camel.

Animals↗

PubMed2004

Separation and purification of ovulation-inducing factors in the seminal plasma of the Bactrian camel (Camelus bactrianus).

Ovulation in the Bactrian camel depends upon ovulation-inducing factors in the seminal plasma. The present study was conducted to isolate and purify the bioactive fractions from the seminal plasma of these camels. The seminal plasma was fractionated by anion-exchange chromatography, and six fractions were obtained. The bioactive potential of each fraction was estimated from its effect on rat pituitary tissue cultured in vitro and by the effect of an intramuscular injection of the fraction into female camels in vivo. Both the third fraction (F3) and the fifth fraction (F5) stimulated the release of LH in vitro and in vivo. In addition, female camels ovulated within 48 h after intramuscular injection of F3. However, neither F3 nor F5 had any significant effect on the secretion of FSH, either in vitro or in vivo. When F3 was further fractionated into four subfractions, the third subfraction (F3-3) still stimulated the in vitro release of LH, but not of FSH. An attempt to further purify the ovulation-inducing factors in F3-3 failed owing to the similarity of the molecular characters.

Animals↗

PubMed2002

Ascorbic acid content of blood plasma, erythrocytes, leukocytes and liver in camels (Camelus dromedarius) without or with parasite infections.

Healthy camels (Camelus dromedaris) and those naturally infected with trypanosomiasis, sarcoptic mange, and helminthiasis were compared as to ascorbic acid (vitamin C) contents of red blood cells, white blood cells, whole blood, plasma, and liver. The camels were kept under natural grazing conditions in Sudan. Reduced levels of vitamin C were found in camels with parasite infections, especially in animals with trypanosomiasis. It is suggested that the low vitamin C status in infected camels is caused by increased utilization and/or decreased synthesis of vitamin C.

Animals↗