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PubMed1988

Effect of inhibition of 5-lipoxygenase metabolism of arachidonic acid on response to endotoxemia in sheep.

We studied the effects of a 5-lipoxygenase inhibitor, L-651,192, on the pulmonary dysfunction caused by endotoxemia in chronically instrumented unanesthetized sheep. The efficacy and selectivity of L-651,392 were tested by measuring in vivo production of leukotriene B4 (LTB4) and cyclooxygenase products of arachidonic acid after endotoxemia before and after pretreatment with L-651,392 and ex vivo from granulocytes and whole blood stimulated with calcium ionophore from sheep before and 24 h after pretreatment with L-651,392. A novel assay for LTB4 by high-performance liquid chromatography/gas chromatography/mass spectrometry techniques was developed as a measure of 5-lipoxygenase metabolism of arachidonic acid. L-651,392 proved to be an effective in vivo 5-lipoxygenase inhibitor in sheep. L-651,392 blocked the increase in LTB4 observed in lung lymph after endotoxemia in vivo in sheep as well as inhibited by 80% the ex vivo production of LTB4 by granulocytes removed from sheep treated 24 h earlier with L-651,392. Although L-651,392 blocked the increase in cyclooxygenase products of arachidonic acid observed in lung lymph after endotoxemia in vivo in sheep, the drug probably did not function directly as a cyclooxygenase inhibitor. L-651,392 did not attenuate the ex vivo production of thromboxane B2 by whole blood from sheep treated 24 h earlier with the drug. L-651,392 attenuated the alterations in pulmonary hemodynamics, lung mechanics, oxygenation, and lung fluid and solute exchange observed after endotoxemia in sheep. We speculate that 5-lipoxygenase products are a major stimulus for cyclooxygenase metabolism of arachidonic acid after endotoxemia in sheep.

Animals↗
PubMed2006

Gene identification and analysis of transcripts differentially regulated in fracture healing by EST sequencing in the domestic sheep.

BACKGROUND: The sheep is an important model animal for testing novel fracture treatments and other medical applications. Despite these medical uses and the well known economic and cultural importance of the sheep, relatively little research has been performed into sheep genetics, and DNA sequences are available for only a small number of sheep genes. RESULTS: In this work we have sequenced over 47 thousand expressed sequence tags (ESTs) from libraries developed from healing bone in a sheep model of fracture healing. These ESTs were clustered with the previously available 10 thousand sheep ESTs to a total of 19087 contigs with an average length of 603 nucleotides. We used the newly identified sequences to develop RT-PCR assays for 78 sheep genes and measured differential expression during the course of fracture healing between days 7 and 42 postfracture. All genes showed significant shifts at one or more time points. 23 of the genes were differentially expressed between postfracture days 7 and 10, which could reflect an important role for these genes for the initiation of osteogenesis. CONCLUSION: The sequences we have identified in this work are a valuable resource for future studies on musculoskeletal healing and regeneration using sheep and represent an important head-start for genomic sequencing projects for Ovis aries, with partial or complete sequences being made available for over 5,800 previously unsequenced sheep genes.

Animals↗
PubMed1975

3,3',5'-Triiodothyronine (reverse T3) and 3,3',5-triiodothyronine (T3) in fetal and adult sheep: studies of metabolic clearance rates, production rates, serum binding, and thyroidal content relative to thyroxine.

To examine the mechanism(s) responsible for high serum concentration of 3,3',5'-triiodothyronine (reverse T3, rT3) and low serum concentration of 3,3',5-triiodothyronine (T3) in the fetus, we studied metabolic clearance rates (MCR) and production rates (PR) of rT3, T3, and thyroxine (T4) in adult nonpregnant sheep and sheep fetuses in utero. The mean fetal MCR-rT3 was significantly lower than that in adult sheep, and the mean fetal PR-rT3 significantly higher. The mean fetal MCR-T3 was higher than, and the mean fetal PR-T3 similar to that in adult sheep. The mean fetal MCR-T4 and PR-T4 were both significantly higher than the corresponding values in adult sheep. The ratios of mean PR-rT3 to PR-T4 (rT3/T4) were similar in fetal and adult sheep. However, the ratio of mean PR-T3 to PR-T4 (T3/T4) in the fetal sheep was much lower than that in the adult sheep. The low fetal MCR-rT3 was not attributable to high serum binding of rT3. On the basis of the thyroidal content and kinetics of iodothyronines, it was estimated that whereas thyroidal secretion may account for nearly all of serum T3 (or PR-T3) in the fetus and about 50% of serum T3 in adults, it accounts for only about 3% of the serum rT3 (or PR-rT3) in both fetal and adult sheep. The results suggest a) that elevated serum rT3 in the fetus is due to its decreased clearance and increased production by mono-deiodination of T4, and b) that low serum T3 in the fetus is due to its increased clearance and decreased production by mono-deiodination of T4. In addition, on the basis of discordant changes in the production of T3 and rT3 from T4, it appears that there may exist two separate, apparently specific, iodothyronine deiodinating activities--one cleaving the iodine atom at the 5'-position and the other acting in the iodine atom at the 5-position of the T4 molecule; 5'-iodothyronine deiodinating activity is apparently reduced in the fetus.

Aging↗
PubMed1992

The enzymatic and release characteristics of sheep neutrophil elastase: a comparison with human neutrophil elastase.

Sheep are often used to study tissue damage following shock after traumatic injury and in the course of other diseases. The processes involved are thought to be caused at least in part by elastase released from polymorphonuclear leukocytes (PMNs). Since little is known about elastase and its role as a mediator of tissue damage in sheep, we studied the biochemical properties and release characteristics to sheep leukocyte elastase (SLE) in comparison of those of human leukocyte elastase (HLE). Both enzymes showed similar molecular masses, amino-acid compositions, N-terminal amino-acid sequences, and abilities to digest elastin substrates. Differences, however, were found in kinetic parameters measured with the elastase-specific substrate N-methoxysuccinyl-(L-alanyl)2-L-prolyl-L- valine-4-nitroanilide (MeoSuc-AAPV-pNa). The Michaelis constant (Km) of ovine elastase was nearly 10 times higher (1.82 mM) than the Km of HLE (0.21 mM). Values of SLE calculated for kcat were 70% and for kcat/Km 8% of corresponding values determined for HLE. In addition, significant differences between sheep and human PMNs were found in in vitro stimulation experiments. In contrast to human PMNs, sheep neutrophils released no active elastase, and only 50 to 70% of the H2O2 produced by human PMNs. This failure to release active elastase could not be explained by a lower elastase content of sheep PMNs, as there were no significant differences found between the elastase contents of sheep and human PMNs. We conclude that elastase liberated by stimulated sheep PMNs is inactivated by a concomitantly released proteinase inhibitor also located within the sheep PMNs.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1999

The influence of sex and gonadectomy on the hypothalamo-pituitary-adrenal axis of the sheep.

There is a sex difference in the hypothalamo-pituitary-adrenal (HPA) axis of many species, although there are sparse data on the sheep. In the present study we have compared the HPA axes of intact and gonadectomised adult male and female sheep at the level of the median eminence, pituitary and adrenal glands using a variety of in vitro approaches. The concentration of arginine vasopressin (AVP) was higher (P<0.01) in the median eminence of male than female sheep, and was also elevated by gonadectomy of either sex (P<0.01). The concentration of corticotrophin-releasing factor (CRF) in the median eminence did not differ between the sexes, but was also elevated in both sexes following gonadectomy (P<0.01). Anterior pituitary pro-opiomelanocortin mRNA concentrations were higher (P<0.05) in intact male sheep than in intact females, with the levels in gonadectomised animals of both sexes being intermediate. In contrast to this finding, basal ACTH secretion from anterior pituitary cells was higher (P<0.05) in cultures derived from female sheep than those from males, but gonadectomy was without effect. There was no effect of sex or gonadectomy on in vitro ACTH secretion in response to AVP, CRF or the combination of AVP and CRF, and in all cases the combination of AVP and CRF generated greater (P<0.0001) ACTH secretion than AVP alone. AVP alone was more effective (P<0.01) than CRF alone as an ACTH secretagogue. The adrenal glands were larger (P<0.05) in female than male sheep, with no effect of gonadectomy. Basal cortisol production was greatest (P<0.05) in cultures of adrenal cells from intact male sheep, though ACTH- and 8BrcAMP-induced cortisol production was greater in the cultures of cells from females (P=0.05); there were no effects of gonadectomy. Cultures of adrenocortical cells from male sheep had greater (P<0.05) basal cAMP production, but ACTH-stimulated cAMP production did not differ between any of the groups of animals. These findings show a range of differences in the HPA axis of male and female sheep. Furthermore, they suggest that the heightened activity of the axis in the female occurs primarily due to differences at the level of the adrenal gland, and that greater adrenal responsiveness of female animals is due to differences in the latter stages of steroidogenesis, rather than an effect on ACTH signal transduction at its receptor.

Adrenal Glands↗
PubMed2002

Contrasting effects of different levels of food intake and adiposity on LH secretion and hypothalamic gene expression in sheep.

Body reserves (long-term) and food intake (short-term) both contribute nutritional feedback to the hypothalamus. Reproductive neuroendocrine output (GnRH/LH) is stimulated by increased food intake and not by high adiposity in sheep, but it is unknown whether appetite-regulating hypothalamic neurons show this differential response. Castrated male sheep (Scottish Blackface) with oestradiol implants were studied in two 4 week experiments. In Experiment 1, sheep were fed to maintain the initial body condition (BC) score of 2.0+/-0.00 (lower BC (LBC), n=7) or 2.9+/-0.09 (higher BC (HBC), n=9), and liveweight of 43+/-1.1 and 59+/-1.6 kg respectively. LBC and HBC sheep had similar mean plasma LH concentration, pulse frequency and amplitude, but HBC animals had higher mean plasma concentrations of insulin (P<0.01), leptin (P<0.01) and glucose (P<0.01). Gene expression (measured by in situ hybridisation) in the hypothalamic arcuate nucleus (ARC) was higher in LBC than HBC sheep for neuropeptide Y (NPY; 486% of HBC, P<0.01), agouti-related peptide (AGRP; 467%, P<0.05) and leptin receptor (OB-Rb; 141%, P<0.05), but lower for cocaine- and amphetamine-regulated transcript (CART; 92%, P<0.05) and similar between groups for pro-opiomelanocortin (POMC). In Experiment 2, sheep with initial mean BC score 2.4+/-0.03 and liveweight 55+/-0.8 kg were fed a liveweight-maintenance ration (low intake, LI, n=7) while sheep with initial mean BC score 2.0+/-0.03 and liveweight 43+/-1.4 kg were fed freely so that BC score increased to 2.5+/-0.00 and liveweight increased to 54+/-1.4 kg (high intake, HI, n=9). Compared with LI, HI sheep had higher mean plasma LH (P<0.05), baseline LH (P<0.01) and pulse amplitude (P<0.01) and showed a trend towards higher pulse frequency. Although there were no differences in final mean plasma concentrations, there were significant increases over time in mean concentrations of insulin (P<0.001), leptin (P<0.05) and glucose (P<0.001) in HI sheep. Gene expression for AGRP in the ARC was higher in HI than LI animals (453% of LI; P<0.05), but expression levels were similar for NPY, OB-Rb, CART and POMC. Thus, the hypothalamus shows differential responses to steady-state adiposity as opposed to an increase in food intake, in terms of both reproductive neuroendocrine activity and hypothalamic appetite-regulating pathways. Differences in hypothalamic gene expression were largely consistent with contemporary levels of systemic leptin and insulin feedback; however, increased nutritional feedback was stimulatory to GnRH/LH whereas constant high feedback was not. The hypothalamus therefore has the ability to retain a nutritional memory that can influence subsequent responses.

Adipose Tissue↗
PubMed2006

Effects of preoperative epidural administration of racemic ketamine for analgesia in sheep undergoing surgery.

OBJECTIVE: To investigate the effects of preoperative epidural administration of racemic ketamine to provide analgesia in sheep undergoing experimental hind limb orthopedic surgery. ANIMALS: 12 adult sheep (weight range, 51.4 to 67.2 kg). PROCEDURE: Sheep were anesthetized with guaifenesin, thiopental, and isoflurane; after induction of anesthesia, sheep received a lumbosacral epidural injection of ketamine (1 mg/kg; n = 6) or saline (0.9% NaCl) solution (1 mL/7 kg; 6 [control group]). Respiratory and cardiovascular variables were recorded before and at intervals during and for 6 hours after anesthesia. During that 6-hour postoperative period, analgesia was evaluated subjectively with a numeric ranking scale that included assessments of comfort, posture, movement, and response to wound palpation; buprenorphine was administered when a score > 3 (maximum score, 10) was achieved. Rectal temperature, heart and respiratory rates, and lameness were evaluated daily for 2 weeks after surgery. RESULTS: At all evaluations, cardiovascular and respiratory variables were comparable between the 2 groups. Compared with control sheep, time to first administration of rescue analgesic was significantly longer and total dose of buprenorphine administered during the 6- hour postoperative period was significantly decreased for ketamine-treated sheep. During the second week following surgery, ketamine-treated sheep had significantly less lameness than control sheep. CONCLUSIONS AND CLINICAL RELEVANCE: In sheep undergoing hind limb surgery, preoperative epidural administration of ketamine appears to provide analgesia in the immediate postoperative period and has residual analgesic effects, which may contribute to more rapid return of normal function in surgically treated limbs.

Analgesics↗
PubMed1997

Hair sheep genetic resources and their contribution to diversified small ruminant production in the United States.

Two Caribbean hair sheep breeds, the St. Croix (SC) and Barbados Blackbelly (BB), are found in the United States, and the SC has led to the development of the Katahdin (K), a synthetic breed of hair sheep. These breeds have mature ewe BW ranging from 32 to 54 kg (for BB and SC) and from 55 to 73 kg (K). Hair sheep and hair sheep crosses have lower rectal temperatures and respiration rates than wool breeds and a lower DMI and water intake. There are indications of increased resistance to internal parasites in hair sheep. Although hair sheep are seasonal breeders under U.S. photoperiodic conditions, they tend to perform better under accelerated lambing systems than traditional wool breeds. Fertility, prolificacy, and lamb survival is high in BB and SC, but hair x wool crossbred ewes tend to have a higher level of fertility than hair and wool parent breeds. Ewe productivity is also higher in hair x wool crosses than in wool crosses, particularly when adjusted for ewe BW or under accelerated lambing systems. Hair sheep have a lower ADG and intake of high-energy diets, as well as a lower gain/feed ratio, than wool breeds. Growth rates tend to be higher in SC than in BB. Differences in carcass characteristics are inconsistent between hair and wool breeds. Production characteristics of hair sheep, particularly hair x wool crosses, make them suitable for low-input, sustainable production systems that do not require high growth rates and large carcasses. There is a need to preserve the existing U.S. hair sheep germplasm base in support of such systems.

Adaptation, Physiological↗
PubMed1986

The voluntary forage intake and nutrition of goats and sheep in the semi-arid tropics of northeastern Brazil.

The nutritive value of diets selected by free-ranging goats and sheep, and estimates of forage intake, were obtained during the wet (January to May, 1982) and the dry season (June to December, 1981) in the Brazilian state of Ceara. Esophageally fistulated animals were used to collect dietary samples for nutritive evaluation. Organic matter intake (OMI) was estimated by total fecal collections. Goats selected diets higher in crude protein (CP) than did sheep (16.3 and 15.5%, respectively; P = .03). Contrary to current hypotheses, goats did not generally select diets of higher nutritional quality than did sheep. Sheep diets had lower (P less than .05) levels of lignin and equal (P greater than .1) levels of cell wall fiber compared with goats' diets. No difference in in vitro organic matter digestibility (IVOMD) was found between sheep and goats (P greater than .1), averaging 54%. However, major differences in IVOMD occurred during the wet season, as sheep diets were 4 to 10 digestibility units higher than were goats' diets. This may have been due to problems in using the in vitro procedure for dietary samples high in browse material. The OMI averaged 2.2 and 2.1% of body weight for sheep and goats, respectively (P = .08). Lowest levels of OMI (1.2% for sheep and goats) were noted during the latter portion of the wet season when forage biomass was high but nutrient quality was declining due to maturation. Daily digestible energy (DE) intake (kcal) differed (P = .04) between sheep (1,665.5 +/- 23.7) and goats (1,329.7 +/- 27.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1988

Effect of cimaterol on sheep adipose tissue lipid metabolism.

Effects of dietary cimaterol (5 mg/kg) on adipose tissue metabolism of wether lambs were studied. Lipogenesis, lipolysis, fatty acid composition and adipocyte size and number were measured. Cimaterol feeding increased lipogenesis; however, this effect was not statistically significant. Insulin (1,000 microU/ml) stimulated lipogenesis of adipose tissue from control sheep. However, this elevated rate was abolished by in vitro cimaterol. Insulin had no stimulatory effect on lipogenesis in cimaterol-fed sheep. Lipolysis was depressed by cimaterol feeding. However, 10(-4) M cimaterol stimulated lipolysis in the adipose tissue from both control and cimaterol-fed sheep. Insulin inhibited stimulated lipolysis in adipose tissue from control sheep but had no effect on the stimulated lipolysis in cimaterol-fed sheep. Mean adipocyte diameter was smaller (from 74 to 70 microns) and adipocyte size distribution also was changed in the cimaterol-fed sheep. Adipocyte number per gram of tissue was not affected by cimaterol. There was a significant increase in percentage of unsaturated fatty acids in adipose tissue from cimaterol-fed sheep. These results indicate that lipogenic and lipolytic responses to insulin and cimaterol in sheep adipose tissue were altered by cimaterol feeding. The carcass fat content decrease in cimaterol-fed sheep may be attributed to the reduction in adipocyte size.

Adipose Tissue↗
PubMed2002

[Genetic polymorphisms of five microsatellite loci in Small Tail Han sheep].

Small Tail Han sheep is an excellent local sheep breed in China. Small Tail Han sheep had significant characteristics of high prolificacy. The lambing percentage averaged 260 percent in Small Tail Han sheep. The polymorphisms of 5 microsatellite loci OarAE101, BM1329, BMS2508, TGLA54 and TGLA68 which were closely linked to the fecundity genes FecB and FecXI in sheep were detected in 244 ewes of Small Tail Han sheep. The PCR amplified products of microsatellites were detected by non-denatured (natural) polyacry lamide gel electrophoresis. Allele frequency, polymorphism information content, gene homogeneity and heterozygosity for 5 microsatellite loci were calculated. The number of alleles for BM1329, OarAE101, TGLA54, TGLA68 and BMS2508 were 6, 9, 5, 2 and 6 in Small Tail Han sheep, respectively. The range of allele sizes for BM1329, OarAE101, TGLA54, TGLA68 and BMS2508 were 160 bp to 180 bp, 97 bp to 135 bp, 116 bp to 136 bp, 98 bp to 100 bp, and 93 bp to 115 bp, respectively. The alleles of the greatest frequency for BM1329, OarAE101, TGLA54 and BMS2508 were 164 bp, 97 bp, 134 bp and 99 bp, respectively. Polymorphism information content/gene homogeneity/heterozygosity for BM1329, OarAE101, TGLA54, TGLA68 and BMS2508 were 0.4481/0.4840/0.5160, 0.3516/0.6375/0.3625, 0.2528/0.7326/0.2674, 0.3733/0.5034/0.4966 and 0.5809/0.3581/0.6419 in Small Tail Han sheep, respectively. The results revealed the greatest genetic variation in BMS2508 and the lowest in TGLA54. These results could provide, basic molecular data for the research on the germplasm characteristics of Small Tail Han sheep.

Animals↗
PubMed2003

The influence of the ovulation rate on ultrasonically determined ovine corpus luteum morphometry and progesterone concentrations in cyclic and early pregnant sheep.

The objective of the present study was to describe morphology and function of the Corpora lutea (CL) during the oestrous cycle and early pregnancy in sheep with different ovulation rates. In total 40 Booroola. Mutton Merino crosses [heterozygous carriers (FecBFec+) and non-carriers (Fec+Fec+) of the Booroola-fecundity gene (FecB)] with ovulation rates 1 to 4 were examined. During the oestrous cycle (n = 20) and the first month of pregnancy (n = 20) blood samples were taken daily (radioimmunoassay of progesterone) and an ultrasonic ovary diagnosis was conducted. The ewes were scanned transrectally with a 7.5 MHz linear probe lying in a dorsal position. During every examination the CL could be detected. The number and the diameter of the CL were documented and the total volume of luteal tissue per ewe was calculated. The effect of the ovulation rate on CL-morphology (diameter and total volume of luteal tissue per ewe) and peripheral progesterone concentrations were assessed by one-way ANOVA. On day 6 and 7 post ovulationem in cyclic and early pregnant sheep 42% of the diagnosed CL had a cavity. On day 11 (cyclic sheep) and day 10 post ovulationem (early pregnant sheep) this number decreased to 22% (p < 0.05). Both conditions of the CL (compact or with a central cavity) are similar in function and should be regarded as appearances of the same basic process. From the third day onwards the ovulation rate influenced significantly (p < 0.05) the development of the outside diameters of the CL. However, the ovulation rate had no effect on the total volume of the luteal tissue per sheep and on the progesterone concentrations. Yet, in sheep with the ovulation rate 1 significantly lower progesterone concentrations were determined than in sheep with the ovulation rates 2 to 4. In sheep with the ovulation rates 2 to 4 the peripheral progesterone concentrations did not differ significantly. In cyclic and pregnant sheep there is a positive correlation (r = 0.75, p < 0.05) between the progesterone concentration and the total volume of luteal tissue. Considering the smaller diameters of the preovulatory follicles it seems that the development of the CL continues until a threshold-value of progesterone and/or of the total luteal tissue is exceeded. Ewes with low ovulation rates reach this threshold-value with only a few but large CL. With increasing ovulation rate the CL tend to have smaller diameters.

Animals↗
PubMed1992

Chromium-51 labeling of sheep red blood cells.

The failure of sheep red blood cells (RBCs) labeled with Chromium-51 (Cr-51) using the ascorbic acid technique to act as a suitable intravascular marker of blood volume in a septic sheep model prompted us to investigate the technique of radiolabeling sheep erythrocytes with this isotope. Consequently, we studied thirteen sheep in which the labeling efficiency of Cr-51 as sodium chromate and hemoglobin typing was determined for each animal. Mean Cr-51 labeling efficiency of sheep RBCs was 67.5% (n = 13). Although 5 of the 13 sheep were discovered to have two types of hemoglobin (Hb) as determined by electrophoresis, overall labeling efficiency of sheep RBCs was determined to be independent of the type of hemoglobin present. However, when two types of Hb were present (Hb-A and Hb-B), Cr-51 had a higher affinity for Hb-B (80%) than Hb-A (20%) even though both Hb types are present in similar proportions (Hb-A = 53%, Hb-B = 46%). The results of this study indicate that sheep RBCs express a lower labeling efficiency for Cr-51 than do human RBCs and that Cr-51 has a higher affinity for Hb-B than for Hb-A when both hemoglobin types are present. This difference is noteworthy when interpreting Cr-51 RBC data in experimental sheep models. Furthermore, caution should be exercised when extrapolating established human protocols to animal models.

Animals↗
PubMed2003

[Chronic sheep modal for pulmonary valve implantation with domestic bileaflet mechanical prosthesis].

OBJECTIVE: The aim of this study was to identify the long-term character of the domestic bileaflet mechanical valve in the chronic implanted sheep model and to evaluate the potential value of the modal. METHODS: Six adult sheep underwent implanted mechanical bileaflet valve in pulmonary position under the cardio-pulmonary bypass with beating heart. The chronic implanted sheep model was built up and observed in the respects of a long-term survival, function of prosthesis and pathological specimen. RESULTS: Six adult sheep survived with good condition after operation. The average survival period of six sheep was (221 +/- 208) days. Two sheep were postoperatively sacrificed in 41 and 71 days, respectively. The necropsy revealed normal valve function without thrombosis, periprosthetic leakage and overgrowth of fibrous tissue. One sheep died from dysfunction of prosthetic valve at the postoperative 196 days. The reason was the prosthetic thrombosis with slight overgrowth of fibrous tissue in periprosthesis. The other two sheep died from severe anemia at the postoperative 196 days and 234 days, and the autopsy revealed no abnormal finding else. And one remained to survive with good condition up to now (over 617 days) and was checked by Doppler echocardiogram twice at the postoperative 438 days and 479 days, respectively. The results showed normal function of the bileaflet valve in pulmonary position. CONCLUSION: The long-term good effects would be achieved by using the implanted new domestic bileaflet valve in pulmonary position of sheep.

Animals↗
PubMed2003

[Polymorphisms of exon 2 of MHC-DRB3 gene in Mongolian and Kazakh Sheep].

MHC(major histocompatibility complex) is a chromosomal region consisting of a group of closely linked loci which are highly polymorphic, which plays a central role in the immune system of animals and is almost found in all vertebrates. Its expressional product is MHC antigen of which main function is antigen presentation. In this study, the exon 2 of MHC-DRB3 gene was amplified by PCR and a uniform fragment of 285 bp was obtained in Mongolian Sheep and Kazakh Sheep. The 285 bp PCR product was digested with restriction endomuclease HaeIII and genetic polymorphism was investigated by PCR-RFLP. Seven alleles were found: A(168 bp/117 bp), B(154 bp/117 bp/14 bp), C(154 bp/65 bp/52 bp/14 bp), D(168 bp/65 bp/52 bp), E(154 bp/131 bp), F(154 bp/66 bp/65 bp), H(220 bp/65 bp). There are seventeen genotypes in the tested populations, BB(154 bp/117 bp/14 bp), CC(154 bp/65 bp/52 bp/14 bp), EE(154 bp/131 bp), HH(220 bp/65 bp), FF(154 bp/66 bp/65 bp), AB(168 bp/154 bp/117 bp/14 bp), AC(168 bp/154 bp/117 bp/65 bp/52 bp/14 bp), AE(168 bp/154 bp/131 bp/117 bp), AH(220 bp/168 bp/117 bp/65 bp), BC(154 bp/117 bp/65 bp/52 bp/14 bp), CE(154 bp/131 bp/65 bp/52 bp/14 bp), CD(168 bp/154 bp/65 bp/52 bp/14 bp), CF(154 bp/66 bp/65 bp/52 bp/14 bp), CH(220 bp/154 bp/65 bp/52 bp/14 bp), DE(168 bp/154 bp/131 bp/65 bp/52 bp), EH(220 bp/154 bp/131 bp/65 bp), FH(220 bp/154 bp/66 bp/65 bp). By analyzing restriction map, polymorphic sites were detected at base position 154, 168 and 220. Statistical results indicated that there are significant differences of some genotypic frequencies and allelic frequencies between Mongolian Sheep and Kazakh Sheep(P < 0.10, P < 0.05 or P < 0.01). CC, FF, BC and B, C, F are favorable genotypes and favorable alleles respectively in Mongolian Sheep and Kazakh Sheep, In addition, HaeIII CE and HaeIII E is favorable genotype and favorable allele respectively in Kazakh Sheep. The results of chi 2 test showed that genotypes of MHC-DRB, gene in Mongolian Sheep and Kazakh Sheep did not fit with Hardy-Weinberg equilibrium(P < 0.01).

Alleles↗
PubMed2005

The comparison of a dentin adhesive with calcium hydroxide as a pulp-capping agent on the exposed pulps of human and sheep teeth.

OBJECTIVE: This study evaluated the biocompatibility of a one-step dentin bonding agent (Prime&Bond 2.1) in pulp capping compared with calcium hydroxide [Ca(OH)2]. METHOD AND MATERIALS: Thirty sheep teeth and 20 intact human premolars were used. After cavity preparation, pulp exposure was achieved with a bur (#390). Adhesive pulp capping was performed in 25 teeth (15 sheep and 10 human). In the control group (12 sheep and 10 human teeth), pulps were capped with Ca(OH)2 and all of the cavities in both groups were sealed with resin composite. Three of the sheep teeth were used as intact controls. Teeth were extracted 7 or 90 days following treatment and prepared for histological examination and bacterial detection. RESULTS: At 7 days, severe inflammatory responses underlying the bonding agent and in the coronal pulp were observed with soft tissue disorganization in both human and sheep teeth capped with Prime&Bond 2.1. All of the teeth capped with Ca(OH)2 exhibited mild inflammatory reactions limited with the perforation area. After 90 days with the bonding agent, in 3 of 9 sheep teeth, chronic inflammatory reactions were significant, while slight pulpal reactions were observed in the others and dentin bridge formation in all of the sheep teeth was found. However, in human pulps, persistent, unresolved inflammation with the lack of dentin bridge formation was observed. In the Ca(OH)2 group, pulp repair with dentin bridging was found in all of the teeth, both sheep and human. No correlation was found between the presence of inflammation and bacterial staining using Spearman rank correlation test (P > .05). CONCLUSION: Prime&Bond 2.1 facilitates enhanced pulp healing and bridge formation in sheep teeth, but in human teeth it was not as successful as Ca(OH)2 as a pulp capping agent.

Acetone↗
PubMed1991

Comparative study of the pharmacokinetics of alfentanil in rabbits, sheep, and dogs.

The central arterial pharmacokinetics of alfentanil, a short-acting opioid agonist, were studied in rabbits, sheep, and dogs after short-duration infusion of the drug. Alfentanil was infused until a set end point (high-amplitude, slow-wave activity on the EEG) was reached. This required a larger alfentanil dose and a higher alfentanil arterial concentration in sheep, compared with rabbits and dogs. The plasma concentration-time data for each animal were fitted, using nonlinear regression, and in all animals, were best described by use of a triexponential function. In this study, differences in the disposition kinetics of alfentanil among the 3 species were found for only distribution clearance and initial distribution half-life. In dogs, compared with rabbits and sheep, the first distribution half-life was longer, probably because of pronounced drug-induced bradycardia (mean +/- SD, 48 +/- 21 beats/min). Distribution clearance was faster in sheep, compared with dogs, also probably because of better blood flow in sheep. Elimination half-life was similar in all species (rabbits, 62.4 +/- 11.3 minutes; sheep, 65.1 +/- 27.1 minutes; dogs, 58.3 +/- 10.3 minutes). This rapid half-life resulted from a small steady-state volume of distribution (rabbits, 908.3 +/- 269.0 ml/kg; sheep, 720.0 +/- 306.7 ml/kg; dogs, 597.7 +/- 290.2 ml/kg) and rapid systemic clearance (rabbits, 19.4 +/- 5.3 ml/min/kg; sheep, 13.3 +/- 3.0 ml/min/kg; dogs, 18.7 +/- 7.5 ml/min/kg). On the basis of these pharmacokinetic variables, alfentanil should have short duration of action in rabbits, sheep, and dogs. This may be beneficial in veterinary practice where rapid recovery would be expected after bolus administration for short procedures or after infusion for longer procedures.

Alfentanil↗
PubMed1990

[The nematode Haemonchus contortus: antigenic characterization and immune response in rabbits and sheep].

In the first part of the study, various tissues of L3 larvae and adult Haemonchus contortus were examined by indirect fluorescence to investigate their antigenicity. L3 larvae were studied in immunoblots as well. The following tissues contained antigens: the sheath and cuticle of L3 larvae; and the cuticle, muscles, epithelium and glandular tissue of the oesophagus and sheath of the spicules of adult nematodes. On the cuticle of exsheathed L3 larvae, we detected by light-microscope slightly raised patches: places where the cuticle differs from the surrounding cuticular morphology. We suggest that the patches are comparable to those found on exsheathed L3 larvae of the horse. Whether the patches produce excretory or secretory antigens or both is unknown, however. Somatic soluble extracts of L3 and adult worms were found to be complex mixtures of proteins by polyacrylamide gel electrophoresis. Results in immunoblots of L3 larvae suggested that the region between the 42 kDa protein and the 18 kDa protein may contain antigens specific for H. contortus. We injected rabbits with the 42-25 kDa fraction of the L3 larvae. The rabbit sera were probed in immunoblots with the total somatic soluble L3 extract for the presence of antibodies. Antibodies reacted with antigens in the 42-25 kDa fraction, however, cross-reactions occurred with antigens in the L3 fractions that were not injected into the rabbits. We found that antibodies against phosphorylcholine were induced and suggest that these cause some of the cross-reactions. In the second part of the study sheep were infected orally with H. contortus and their lymphocyte responses towards L3 antigen and mitogen were measured in a lymphocyte stimulation test. Lymphocyte responses to L3 antigen are expressed in a stimulation index. Two groups of worm-free raised sheep were inoculated (sheep older than 1 year and lambs that were 4 to 6 months old) as well as a group of hyperimmunized sheep. Some sheep were inoculated only once; others were inoculated and then challenged. Lymphocytes of sheep that were hyperimmunized replicated rapidly in the test resulting in significantly higher stimulation indices than those recorded for the lymphocytes of all other sheep. After inoculation the enhanced response further increased. We explain these lymphocyte responses as a result from the immunological memory induced during the hyperimmunization. Lymphocytes of sheep over 1 year old only respond in the test when sheep are infected.(ABSTRACT TRUNCATED AT 400 WORDS)

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