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At least 325 records · Page 18Linked to original sources
PubMed1992

Detection of rabbit haemorrhagic disease virus particles in the rabbit liver tissues.

Liver tissues from rabbits experimentally infected with rabbit haemorrhagic disease virus (RHDV) were studied electron microscopically. The earliest change in hepatocytes of the rabbits infected with RHDV was hydropic degeneration. Rough endoplasmic reticulum was dilated with a mild increase in polysomes and cytoplasmic cisternae in degenerated hepatocytes. Characteristic cytopathological changes of necrotic hepatocytes included shrinkage of the cell body, formation of cytoplasmic vesicles, vacuoles or cisternae and karyolysis. A large number of viral particles resembling a calicivirus in size and morphology was demonstrated in the cytoplasm of many necrotic hepatocytes. The particles had accumulated mainly in the membrane-bound cisternae or scattered around the membrane-bound vacuoles of the necrotic hepatocytes. Western blot analysis demonstrated that RHDV antigen was present in the infected hepatocytes. RHDV particles were also detected by immunoelectron microscopy. Replicating patterns of RHDV particles and subsequent cytopathology resembled those in other calicivirus infections.

Animals↗
PubMed1985

C6-deficiency in rabbit serum and its restoration by normal rabbit serum or by normal bovine serum.

The sera from 12 out of 29 half-sibs of the New Zealand White breed of rabbit were inactive, when used as complement, in blood-typing tests of bovine erythrocytes. This defect was found to be due to a deficiency in the activity of the component C6. A dilution of 1:380 of pooled normal rabbit sera and a dilution of 1:520 of pooled normal bovine sera were capable of restoring, to 63%, the haemolytic capacity of the defective rabbit sera. The rate of haemolysis varied from 4% to 100% when the defective sera were restored by sera from different sets of monozygous bovine twins.

Animals↗
PubMed1991

Humoral and cellular immune response of rabbits to Psoroptes cuniculi, the rabbit scab mite.

Rabbits infested for the first time with Psoroptes cuniculi (Group A) and heavily infested ones with unknown aetiology (Group B) were examined for specific serum antibody activity and responsiveness of their peripheral blood lymphocytes by the enzyme-linked immunosorbent assay and lymphocyte transformation assay methods. These parameters were examined after treatment with ivermectin and after subsequent challenge infestation with P. cuniculi. Group A rabbits developed a small number of mite-caused lesions, and exhibited a significant P. cuniculi antigen-induced T cell response and a high level of specific serum antibody. However, both lymphocyte responsiveness and antibody production were observed to be suppressed in Group B rabbits that were highly susceptible to P. cuniculi.

Animals↗
PubMed2005

Towards a vaccine for attaching/effacing Escherichia coli: a LEE encoded regulator (ler) mutant of rabbit enteropathogenic Escherichia coli is attenuated, immunogenic, and protects rabbits from lethal challenge with the wild-type virulent strain.

The ler (LEE encoded regulator) gene product is a central regulator for the genes encoded on the locus of enterocyte effacement (LEE) pathogenicity island of attaching/effacing (A/E) pathogens, including human enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) as well as animal isolates. Although an in vivo role for Ler in bacterial virulence has not been documented, we hypothesized that a Ler deletion mutant should be attenuated for virulence but might retain immunogenicity. The goals of this study were to genetically characterize ler of a rabbit EPEC (rEPEC) strain (O103:H2), to examine the effect of ler on in vivo virulence, and to determine if intragastric inoculation of an attenuated rEPEC ler mutant was immunogenic and could protect rabbits against subsequent challenge with the wild-type virulent parent strain. The predicted ler gene product of rEPEC strain O103:H2 shares high homology (over 95% amino acid identity) with the Lers of another rEPEC strain RDEC-1 (O15:H-) and human EPEC and EHEC. A defined internal ler deletion mutant of rEPEC O103:H2 showed reduced production of secreted proteins. Although orogastric inoculation of rabbits with the virulent parent O103:H2 strain induced severe diarrhea, significant weight loss and early mortality with adherent mucosal bacteria found at sacrifice, the isogeneic ler mutant strain was well tolerated. Animals gained weight and showed no clinical signs of disease. Examination of histological sections of intestinal segments revealed the absence of mucosal bacterial adherence. This result demonstrates an essential role for Ler in in vivo pathogenicity of A/E E. coli. Single dose orogastric immunization with the rEPEC ler mutant induced serum IgG antibody to whole bacteria (but not to intimin). Immunized animals were protected against enteric infection with the WT virulent parent strain exhibiting normal weight gain, absence of diarrhea and absence of mucosally adherent bacteria at sacrifice. Such attenuated ler mutant strains may have potential for use as oral vaccines, or as vaccine vectors for delivery of foreign antigens. It remains to be determined whether such regulatory mutants can protect against infection with A/E bacteria of differing serotypes affecting different hosts.

Adhesins, Bacterial↗
PubMed1997

Reduction of myocardial infarct size in rabbits and inhibition of activation of rabbit and human neutrophils by lidocaine.

Myocardial reperfusion is associated with increased influx of activated neutrophils and intracellular accumulation of sodium in the ischemic zone. Lidocaine is a sodium channel blocker that also inhibits several neutrophil functions. We investigated the effect of lidocaine on infarct size in rabbits undergoing 30 minutes of ischemia and 48 hours of reperfusion. Animals randomly received lidocaine (10 mg/kg, n = 11) or saline (n = 11) during occlusion. The area of necrosis (AN) was measured histologically and expressed as a percentage of the area at risk (AR). Myocardial oxygen consumption and the perfusion bed at risk were similar in the two groups. Lidocaine reduced infarct size compared with control (AN/AR = 30% +/- 4% vs 61% +/- 5%, respectively; p = 0.0001). This reduction was associated with a significant decrease in neutrophil infiltration and in the degree of hemorrhage in the reperfused myocardium. Lidocaine also significantly inhibited superoxide anion production by rabbit and human neutrophils in whole blood. Therefore, lidocaine treatment results in a significant reduction in infarct size in the rabbit model, partly through reduction of neutrophil-mediated injury to viable cells, suggesting that lidocaine may be useful to enhance myocardial salvage in patients undergoing pharmacologic or mechanical reperfusion.

Animals↗
PubMed2002

Spermicidal effects of amphotericin B and nystatin on bull and rabbit sperm and contraceptive effects in rabbits.

Vaginal contraceptives have potential for controlling reproduction as well as sexually transmitted diseases. Two extensively used fungicides, amphotericin B and nystatin, were found to be highly spermicidal to bull and rabbit sperm even in the presence of organic material found in milk and egg yolk, both excellent components of media designed to preserve sperm. In repeated tests with many samples of bull and rabbit sperm, as little as 0.5 micro g/mL of amphotericin B completely immobilized sperm after prolonged exposure, and 1000 micro g/mL immobiled sperm in less than 1 min. Treatment of rabbit sperm with 1000 micro g of solubilized amphotericin B in 0.4 ml of a glucose-semen mixture before insemination resulted in a total of 2 young born from 9 inseminated Dutch does, compared with 55 young from 9 control does. As this inhibition was achieved without the use of enhancing foams or gels, these results provide promising leads for contraceptive research.

Amphotericin B↗
PubMed1992

Mast cells in the anterior uvea of the rabbit. Intraocular effects of compound 48/80 in the rabbit.

In the present study, the presence and localization of mast cells and the intraocular effects of compound 48/80 have been studied in detail in the rabbit eye using histochemical and physiological methods. In histochemical studies mast cells were localized in the anterior uvea, especially in the ciliary and iridial processes. Intracamerally injected, compound 48/80 caused an increase in the intraocular pressure, disruption of the blood-aqueous barrier and an increase in the cAMP content in the aqueous humour. Miosis was observed only after higher doses of compound 48/80 (greater than 100 micrograms) and even then only one-half of the eyes responded. The intraocular effects, excluding miosis, of compound 48/80 resembled an on/off-type of response, where 20 micrograms caused only minor changes, if any, and 50 micrograms gave a maximal response. The ocular hypertensive reaction developed a tachyphylaxis so that the second and third consecutive dose of compound 48/80 (100 micrograms) produced no significant change in IOP. The results indicate that mast cells, which are present in the anterior uvea in an extent not known previously, might be involved in certain inflammatory reactions in the rabbit eye. The inconsistent and slight miosis after the intracameral application of compound 48/80 indicates that the mechanism is different from that caused by sensory nerve stimulation. The rapid development of tachyphylaxis after consecutive application of compound 48/80 suggests that mast cells are easily depleted which might be useful for further studies to evaluate the functional role of mast cells in different pathophysiological conditions in the rabbit eye.

Animals↗
PubMed1991

Pulmonary intravascular macrophages in rabbits experimentally infected with rabbit haemorrhagic disease.

Attention has already been drawn to the presence of pulmonary intravascular macrophages (PIMs) in species in which the lung plays an important part in the removal of particles from the bloodstream. The stimulation of PIMs under certain conditions has been related to pulmonary oedema and congestion. In order to ascertain whether these cells are found in rabbits, healthy animals were inoculated with a liver homogenate obtained from animals which had died of rabbit haemorrhagic disease, a condition characterized by vascular phenomena and pulmonary oedema. PIMs were detected both in experimental and healthy control animals. They shared the morphological characteristics reported for other species, particularly with respect to the presence of intercellular junctions with endothelial cells. In experimental animals, PIMs were actively involved in the removal of cell debris which may or may not have been associated with the presence of rabbit haemorrhagic disease virus antigen.

Animals↗
PubMed1986

Characterization of a specific antiserum to rabbit stromelysin and demonstration of the synthesis of collagenase and stromelysin by stimulated rabbit articular chondrocytes.

An antiserum to rabbit bone stromelysin (proteoglycanase) was raised in sheep and characterized as specific, recognizing the enzyme from both different tissue sources and different species. This antiserum and a specific antiserum to rabbit bone collagenase were used in the study of metalloproteinase production by rabbit articular chondrocytes stimulated with either interleukin 1 or mononuclear cell-conditioned medium. It was shown by electroimmunoblotting that the apparently co-ordinate (mole:mole) induction of collagenase and stromelysin activity with time correlated in either case with an increase in enzyme protein. The stimulated production of both enzymes could be modified in parallel by a variety of compounds. Immunohistochemical studies confirmed that although most cells were producing both metalloproteinases simultaneously, some chondrocytes produced detectable levels of only one. The data are discussed in relation to the mechanisms of breakdown in connective tissues.

Animals↗
PubMed1998

Probucol inhibits neointimal formation in carotid arteries of normocholesterolemic rabbits and the proliferation of cultured rabbit vascular smooth muscle cells.

The proliferation of vascular smooth muscle cells (VSMCs) plays an important role in the formation of atherosclerotic lesions and restenosis after angioplasty. It has been suggested that probucol inhibits VSMCs proliferation, but this effect has not been directly demonstrated. In this study we investigated the effect of probucol on neointimal formation after balloon injury in normocholesterolemic rabbits and examined whether probucol could inhibit the proliferation of rabbit cultured VSMC stimulated by fetal bovine serum (FBS). Probucol inhibited the formation of neointima by about 63% 2 weeks after balloon injury. Probucol inhibited the increase in the number of cultured VSMCs and bromodeoxyuridine (BrdU) incorporation stimulated by 10% FBS in a dose-dependent manner. Also, 10% FBS stimulated the activities of mitogen-activated protein kinase (MAP kinase) and protein kinase C (PKC) in cultured VSMCs. Probucol inhibited these activities in a dose-dependent fashion. These results suggest that probucol may inhibit neointimal formation after balloon injury in normocholesterolemic rabbits by preventing the proliferation of VSMCs via inactivation of MAP kinase and PKC.

Animals↗
PubMed1979

Rabbit beta-globin mRNA production in mouse L cells transformed with cloned rabbit beta-globin chromosomal DNA.

Mouse thymidine kinase-negative L cells were transformed with a cloned rabbit chromosomal beta-globin gene linked to the clone thymidine kinase gene of herpes simplex virus type 1. Most thymidine kinase-positive cell lines contained one or more copies of rabbit beta-globin DNA and produced up to 2,000 copies of rabbit beta-globin RNA per cell indistinguishable from its authentic counterpart. No mouse beta-globin mRNA was detected.

Animals↗
PubMed1981

The effect of cholesterol feeding on gallbladder bile acids of the rabbit. Evidence that lithocholic acid is a primary bile acid in the rabbit.

The bile acid in gallbladder bile of rabbits fed a normal diet or one containing 2% (w/w) cholesterol have been determined by gas chromatography-mass spectrometry. The predominant bile acids in normally fed rabbits were 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholan-24-oic acid (cholic acid), 3 alpha, 12 alpha-dihydroxy-5 alpha-cholan-24-oic acid (allodeoxycholic acid) and 3 alpha, 12 alpha-dihydroxy-5 beta-cholan-24-oic acid (deoxycholic acid) with very much smaller amounts of 3 alpha-hydroxy-5 beta-cholan-24-oic acid (lithocholic acid) and 3 alpha, 12 beta-dihydroxy-5 beta-cholan-24-oic acid. In the cholesterol-fed animals the lithocholate became a predominant bile acid. Sulphated bile acids accounted for less than 1% of the total bile acids. It is proposed that lithocholic acid may be a primary bile acid in the cholesterol-fed rabbit, formed by an alternative pathway of biosynthesis involving hepatic mitochondria.

Animals↗
PubMed2002

Restriction fragment alleles of the rabbit IGHG genes with reference to the rabbit IGHGCH2 or e locus polymorphism.

Among domesticated mammals, rabbit (Oryctolagus cuniculus) is the only species possessing not more than one subclass of immunoglobulin (IgG) antibodies. The rabbit IGHGCH2 or e locus presents two serologically defined alleles, the e14 and e15 allotypes, which are correlated with amino acid variation at the IgG CH2-CH3 interface. Genetic studies, while revealing the adaptive value of this polymorphism, have relied so far entirely upon allo-antisera. Here we show how these alleles can be distinguished by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. The proposed PCR-RFLP approach allows the monitoring of IGHG locus diversity in rabbit.

Animals↗
PubMed2001

Metabolism of rabbit angiostatin glycoforms I and II in rabbits: angiostatin-I leaves the intravascular space faster and appears to have greater anti-angiogenic activity than angiostatin-II.

Plasminogen (PLG) exists in the circulation as two glycoforms, I and II. Angiostatin (AST) is a polypeptide that has been cleaved from the kringle region of PLG and has strong anti-angiogenic properties. AST-I and AST-II, which consisted only of kringles 1 through 3, were prepared by the action of urokinase on purified rabbit PLG-I and PLG-II, respectively, in the presence of N-acetyl cysteine, followed by affinity chromatography on lysine-Sepharose. Purified AST-I and AST-II were tested for functional activity with a chick chorioallantoic membrane (CAM) model; when similar amounts were applied to a 6-day CAM, AST-I was substantially more effective than AST-II in decreasing vascular supply to the CAM over a 72-hour period; this activity correlated with a loss of capillaries, probably through apoptosis of endothelial cells. Radiolabeled AST-I and AST-II (iodine 125 and iodine 131) were co-injected intravenously into healthy rabbits to determine their clearances from plasma measured over 3 days. Over a dose range of 0.08 to 2.7 microg/kg, the fractional catabolic rate within the intravascular space (j(3)) indicated that AST-I was cleared 3-fold to 4-fold more rapidly than AST-II (P < .001). The catabolic half-life of AST-I (2.01 +/- 0.19 days) was significantly less than that of AST-II (2.62 +/- 0.20 days). The faster clearance of AST-I from the intravascular space was matched by its more rapid passage than AST-II to the extravascular space of various organs over 60 minutes in vivo. This property of AST-I as compared with AST-II may partially explain its greater anti-angiogenic potential. From the plasma concentrations of PLG-I and PLG-II and their relative behaviors toward rabbit VX-2 lung tumors in vivo, we predict that substantially greater quantities of AST-II than AST-I may be released into the extravascular space of tumors.

Angiostatins↗
PubMed1980

Evidence for formation of a rabbit liver aldolase--rabbit liver fructose-1,6-bisphosphatase complex.

The ability of rabbit liver aldolase (D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphatate-lyase, EC 4.1.2.13) and rabbit liver fructose-1,6-bisphosphatase (Fru-P2ase; D-fructose-1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11) to partition into the gel phase of Ultrogel AcA 34 is decreased in a mixture of the two enzymes. Titration experiments indicate that a 1:1 complex is formed. The value for the distribution coefficient of the complex corresponds to a molecular mass of 300,000 daltons, the value expected for a dimer containing one mole of each enzyme protein. Complex formation was not observed when either liver enzyme was replaced by the corresponding isozyme from rabbit muscle. The susceptibility of liver Fru-P2ase to limited proteolysis by subtilisin was reduced in the presence of liver aldolase, but not when the latter was replaced by muscle aldolase, suggesting that the conformation of Fru-P2ase is altered in the complex. Limited proteolysis of liver aldolase abolishes its ability both to form the heterodimer and to protect Fru-P2ase from modification by subtilisin.

Allosteric Regulation↗
PubMed1985

Enhancement of antibody response by mouse dendritic cells pulsed with tobacco mosaic virus or with rabbit antiidiotypic antibodies raised against a private rabbit idiotype.

The role of splenic lymphoid dendritic cells (DC) and macrophages (M phi) from mice in induction of immune responses in vivo has been investigated. Varying numbers of purified DC and M phi pulsed in vitro with tobacco mosaic virus (TMV) or with rabbit antiidiotypic antibodies (Ab2) directed against a private rabbit anti-TMV idiotype were injected back into syngeneic mice. In both systems, DC appeared to strongly enhance the primary and secondary responses to the virus. Optimal responses were obtained with 5 X 10(4) purified DC carrying TMV or rabbit Ab2. In contrast, M phi were less efficient by a factor of at least 100. These results show the potency of lymphoid DC as inducing cells in T-dependent antibody responses in vivo.

Animals↗
PubMed1967

Studies on rabbit lymphocytes in vitro. V. The induction of blast transformation with sheep antisera to rabbit IgG subunits.

The addition of sheep antisera to rabbit IgG or to rabbit IgG subunits (L chain, H chain, Fab piece, Fc piece) to in vitro cultures of rabbit peripheral lymphocytes may induce up to 80-90% of the small lymphocytes to transform into immature "blast" cells. As many as 1 x 10(7) molecules of antibody may be required to stimulate each cell. It is concluded that each peripheral lymphocyte carries the antigenic specificities of the entire IgG molecule and thus could carry, and may produce specific antibody molecules. Such a conclusion supports the theory that the small lymphocyte may be the site of specific recognition of antigens in the primary response.

Animals↗
PubMed1969

Idiotypy of rabbit antibodies. II. Comparison of idiotypy of various kinds of antibodies formed in the same rabbits against Salmonella typhi.

The idiotypic patterns detected in the anti-Salmonella typhi serum of one given bleeding have been sought in other bleedings of the same rabbit. Idiotypic patterns carried by antibodies of the second bleeding are not always found in those of the first bleeding. Bifurcated precipitation zones in gels (double diffusion in cells) have been observed in the reaction of several anti-idiotypic sera with the sera of the first and second bleedings of three rabbits, and apparently indicate that idiotypic patterns which were carried by the same molecule in the first bleeding were carried by two separate molecules in the second bleeding. In a comparison of idiotypy of two anti-S. typhi serum samples of one rabbit, the collection of which had been separated by a very long interruption of the immunization, all the idiotypes detected in the early bleeding were also detected in the late bleeding; several idiotypes were detected in the serum of the late bleeding and not in that of the early bleeding. Idiotypy has been observed and compared in IgM and in IgG antibodies. There are, in each of these two classes, antibodies that are not distinguished from antibodies of the other class by anti-idiotypic sera, and consequently that carry the same idiotypic patterns. A comparison has been made between the idiotypy of the two kinds of antibodies which, in anti-S. typhi sera, are precipitated and not precipitated by the polysaccharide. Certain idiotypic patterns are carried only by the antibodies of the first kind. There are also idiotypic patterns which are carried by antibodies of these two kinds, among which certain anti-idiotypic antibodies do not discriminate. Possible cellular implications of observations made on idiotypy at different stages of the immunization of one individual have been discussed.

Animals↗