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At least 19 recordsLinked to original sources
PubMed1978

In vitro studies of the rabbit immune system. VI. Rabbit anti-mouse cytotoxic T effector cells are inhibited by anti-rabbit T cell serum in the absence of complement.

Xenogeneic rabbit anti-mouse cell-mediated cytotoxic activity could be generated by culturing lymphoid cells from mesenteric lymph nodes (MLN), spleen, or peripheral blood of rabbits primed 2 to 8 weeks earlier with mouse tumor or spleen cells. MLN cells, which provided the best source of activity after being cultured with 5 to 10 X 10(6) mitomycin C-treated mouse spleen cells for 4 to 6 days, produced 30 to 90% specific isotope release after 4 to 7 hr incubation with 15Cr-labeled tumor target cells. Xenogeneic cytotoxic activity was primarily H-2 specific and could not be blocked by immune complexes but was abrogated by treatment with goat anti-rabbit thymocyte serum plus complement (ATS + C) before or after culture. Therefore, the activity appeared to be mediated by cytotoxic T lymphocytes (CTL). Furthermore, ATS without C abrogated cytotoxic activity when included in the CTL assay at concentrations of 5 to 15 microliter/10(7) effector cells. The inhibitory activity of ATS was directed to the rabbit effector population and could be absorbed completely by rabbit thymocytes. Antisera to mouse T cells with comparable cytolytic activity in the presence of C did not inhibit murine allogeneic CTL.

Animals↗
PubMed1977

Topographic determinants on cytochrome c. I. The complete antigenic structures of rabbit, mouse, and guanaco cytochromes c in rabbits and mice1.

Rabbit, mouse, and guanaco cytochromes c differ from each other by only two amino acid residues. The identification is described of all of the antigenic determinants of mouse and guanaco cytochrome c that elicit an antibody response in rabbits, and those of the rabbit and guanaco proteins that elicity antibodies in the mouse. All except one of these sites center around single amino acid residue differences between the antigen and the host cytochrome c. The corresponding antibody popylations bind only to the areas of the protein in which the substitutions occur. Such antigenic determinants manifested in rabbits by quanaco and mouse cytochromes c are centered around residues 62 and 89, and residues 44 and 89, respectively. Similarly, the mouse recognizes sites containing residues 44 and 62 in guanaco cytochrome c, and residues 44 and 89 in rabbit cytochrome c. In none of these instances has a change in sequence failed to produce an antibody response. Each of these determinants appears to elicit and bind to its antibody, independently of other determinants present on the protein. In addition, two different autoantigenic responses have been detected. The antibodies produced against the determinant formed by glutamyl residue 62 of the guanaco protein in both rabbits and mice, the cytochromes c of which carry an aspartyl residue in that position, also bind to the aspartyl-containing region but with lower affinity. However, mouse and rabbit cytochrome c also elicit antibodies to the area of residue 62 in rabbits and mice, respectively, and these antibodies still bind more strongly to the glutamyl-than to the aspartyl-containing determinant. This last response occurs only when there are residue substitutions elsewhere in the molecule, because mice and rabbits fail to respond to their own cytochrome c. Antibodies produced in mice against the change from alanyl to valyl residue 44 by rabbit and guanaco cytochromes c also bind to the alanyl-containing determinant, except less tightly than to the valyl region. Conversely, antibodies raised in rabbits against the change from valyl to alanyl residue 44 only bind to this region when it carries an alanine. It is suggested that antigenic determinants that arise as a result of amino acid residue substitutions between the immunizing and the corresponding host protein, without a change in the spatial arrangement of the polypeptide backbone, be termed topographic determinants.

Amino Acid Sequence↗
PubMed1976

Urinary excretion of retinol-binding protein (RBP) in rabbit chronically poisoned with cadmium. Isolation and partial characterization of rabbit RBP.

Studies were conducted to induce urinary excretion of retinol-binding protein (RBP) in the rabbit by long-term administration of cadmium, and to isolate and characterize rabbit RBP. Two rabbits were exposed to Cd at a dose of 0.8 and/or 1.5mg/kg of body weight by means of subcutaneous injections five times per week. One rabbit excreted large amounts of protein (0.8 to 1.6 g/day) from days 80 to 118. The electrophoretic patterns of the urinary protein showed two fluorescent bands specific for protein-bound retinol in the alpha-region; these were presumed to be RBP. Rabbit RBP was isolated from the pooled urine (10.3 liters) by a sequence of procedures which included gel filtration on Sephadex G-100 and chromatography on DEAE- and SP-Sephadex. Purified RBP (20 mg) was found to be homogeneous by physical and immunological criteria. The RBP had alpha-mobility, with a molecular weight of approximately 20,000. The properties of rabbit RBP resembled those of human RBP simultaneously isolated from the urine of patients with "Itai-Itai" disease in many ways: ultraviolet and fluorescence spectra, and amino acid compositions. A monospecific anti-rabbit RBP antiserum was raised in a goat. There was no immunological cross-reactivity between rabbit and human RBP. The molecular size of the retinol-containing protein in fresh rabbit serum was estimated to be about 60,000 to 70,000 by gel filtration on Sephadex G-200. Rabbit RBP in the serum was also shown to be immunologically identical with purified RBP from the urine.

Amino Acids↗
PubMed1976

Bubonic plague from exposure to a rabbit: a documented case, and a review of rabbit-associated plague cases in the United States.

A 62-year-old woman developed bubonic plague with an epitrochlear bubo one to two days after skinning two cottontail rabbits. The implicated rabbits were later recovered from the patient's freezer, and Yersinia pestis was isolated from marrows of both rabbits. Although human plague cases in the United States have occasionally been traced to exposure to wild rabbits, this is the first documentation of plague infection in the actual rabbits to which the patient was exposed. All reported cases of rabbit-associated plague in the United States were then reviewed. Eight cases were characterized by direct exposure to rabbit tissues. Seven of the eight cases occurred in adult males who had hunted rabbits during winter months in plague-endemic areas. These patients had upper extremity buboes, and the case-fatality ration for the group was 50%. Three other cases in which rabbit exposure was indirect or its role less clear, were also analyzed.

Animals↗
PubMed1977

The effect of indomethacin blockade of prostaglandin synthesis on blood pressure of normal rabbits and rabbits with renovascular hypertension.

Indomethacin inhibits the synthesis of prostaglandin and the release of renin. These effects were studied in normal rabbits and rabbits with two-kidney Goldblatt hypertension (2KGH) and one-kidney Goldblatt hypertension (1KGH) by giving daily intravenous injections of indomethacin (3mg/kg after two initial doses of 9 mg/kg), and in appropriate control rabbits given diluent phosphate buffer without indomethacin. In normal rabbits, indomethacin significantly decreased immunoreactive plasma prostaglandin E-like substance (IPGE) and plasma renin activity (PRA). Indomethacin did not change plasma creatinine (PCr) or mean blood pressure but it decreased renal blood flow (RBF) and glomerular filtration rate (GFR). In 2KGH rabbits, responses depended on the level of renal function and, to a lesser extent, on the level of PRA. In six of10 2KGH rabbits in which hypertension developed without significant changes in PRA, IPGE, PCr, RBF, and GFR, indomethacin produced changes similar to those seen in normals. In the other four rabbits, development of 2KGH was accompanied by increased PRA, increased IPGE, and decreased RBF and GFR, and indomethacin produced renal failure, oliguria, malignant hypertension, and death within 5 days. In 1KGH rabbits, indomethacin decreased IPGE, PRA, and renal function but increased mean blood pressure. These observations suggest that prostaglandins exert a protective effect on renal function in renovascular hypertension.

Animals↗
PubMed1979

[Rearing of germfree rabbits and establishment of an SPF rabbit colony].

Baby rabbits hysterectomy-derived from conventional Japanese white rabbits were reared under aseptic condition by feeding with 4 types of artificial diets. Rabbit milk for the artificial diet was obtained from conventional dams at 7--25 days after delivery. The artificial diets was given by stomach tube twice a day. The total volumes of diet given (ml per day) were Y = 2.3X + a (1 to approximately 14 days of age), Y = 32.2 + a (l5 to approximately 25 days of age), or Y = (32.2 + a) - 37.5 (X - 25) (26 to approximately 34 days of age), (X = age in days, a = volumes fed at 0 day of age). After 14 days of age young animals were also fed freely sterilized commercial pellets and weaned at 35 days of age. Out of 155 rabbits, 130 were aseptically reared till 36 approximately 40 days of age, and no difference on weaning rate was seen between the 4 groups of rabbits. Thereafter, they were exposed to a barriered room of SPF rabbitry outside the isolators. The best growth was seen in animals given by artificial diet containing rabbit milk at 40%. The SPF breeding colony of rabbits was found to be free of Pasteurella pneumotropica, Bordetella bronchiseptica, Salmonella spp., Eimeria spp., Encephalitozoon cuniculi and Acaritic otistis.

Animal Feed↗
PubMed1976

High density lipoprotein (HDL) polymorphisms in rabbit. I. A comparative study of rabbit and human serum high density lipoprotein.

Different classes of rabbit serum lipoprotein were prepared by ultracentrifugal flotation at densities 1-006, 1-063 and 1-21 g/ml. Agarose gel electrophoresis on rabbit whole serum and the serum fractions with different densities showed that this technique separates the different lipoprotein classes reasonably well. The electrophoretic mobility of the different lipoprotein classes of rabbit serum seems to be similar to that of the human lipoproteins, with the exception of alpha1-lipoprotein which had a greater mobility than human alpha1-lipoprotein. The chemical composition of rabbit high density lipoprotein (HDL)p was fairly similar to that of human HDL although the former seems to be richer in triglycerides. HDL was, after isolation by ultracentrifugal flotation at density 1-21, delipidated and submitted to gel filtration on Sephadex G-200 in 8 M urea. The major protein fraction of rabbit apo HDL corresponds in elution volume to that of the major fraction of human apo HDL, apoA-I. A protein fraction corresponding to human apoA-II does not seem to be present in rabbit HDL in demonstrable amounts. The rabbit protein fraction sometimes appearing in the area corresponding to human apoA-II could not be found to be affected by the reduction and alkylation method after which human poA-II splits into two identical chains.

Animals↗
PubMed1975

Non-helical sequences of rabbit collagen. Correlation with antigenic determinants detected by rabbit antibodies in homologous regions of rat and calf collagen.

Non-helical peptide fragments were isolated from rabbit skin collagen after cleavage of alpha chains with cyanogen bromide and proteases. Determination of their amino acid sequence indicated a length of 9, 16 and 25 amino acid residues for the non-helical sequences located in the N-terminal region of alpha2 and alpha1 chain and in the C-terminal region of alpha1 chain, respectively. The C-terminal sequence Tyr-Tyr hitherto considered as the genuine end of collagen alpha1 chain is in part of rabbit collagen extended by two residues, alanine and arginine. Rabbit collagen may differ considerably in its non-helical sequences from other vertebrate collagens, particularly in the C-terminal part. Some but not all of these differences are clustered in areas occupied by antigenic determinants which are recognized in the antibody response of rabbits to rat or calf collagen. On the other hand, a high homology to rabbit collagen, e.g. in the N-terminal region of rat collagen alpha1 chain or calf collagen alpha2 chain, probably prevents immunological recognition by the rabbit. The degree of foreignness alone, however, may not necessarily determine whether a particular non-helical area is able to express immunogenic activity.

Amino Acid Sequence↗
PubMedDate not supplied

[Mg 2+, Ca 2+-ATPase of skeletal muscle nuclei in normal rabbits and in rabbits with experimental muscular dystrophy].

The total ATPase activity of the rabbit skeletal muscle nuclei was established to be a sum of activities of two ATPases--Mg2+ and Mg2+, Ca2+-ATPases. The latter composes 50% of total ATPase activity for skeletal muscles nuclei of the normal rabbits and 30% for skeletal muscles nuclei of the rabbits with muscular dystrophy. Mg+, Ca2+-ATPase of the skeletal muscle nuclei is activated by calcium ions within a range of 10(-6)--10(-4) M and is inhibited with its concentration of 0.5-10(-3) M and higher. Sodium and potassium ions activate Mg2+, Ca2+-ATPase. Inhibition of Mg2+-ATPase is observed for the skeletal muscle nuclei of the rabbits in norm with the presence of 80 mM of Na+ and 70 mM of K+ in the incubation medium. Under experimental muscular dystrophy such an effect is not observed in connection with the fact that the concentration of monovalent cations in the incubation medium does not exceed 60 mM. The ATPase activity in nuclei of the rabbit skeletal muscles may be also manifested in the presence of Mn2+ greater than Ca2+ greater than Ba2+. A problem is under discussion as to substitution of ions Mg2+ by ions Mn2+, Ca2+, Ba2+ in manifestation of the Mg2+ATPase activity for the skeletal muscle nuclei of the normal rabbits and of those with experimental dystrophy.

Adenosine Triphosphatases↗
PubMed1978

Characterization of cardiac myosin from rabbit embryos and adult rabbits.

1. Ca2+-ATPase of myosin and electrophoretic pattern of light chains of myosin were investigated in cardiac muscles of 22-day-old rabbit embryos, new-born and adult rabbits. 2. Ca2+-ATPase activity was found to decrease during development and in contrast to that of adult rabbit, cardiac myosin prepared from 22-day-old embryos, is stable on exposure to pH 9.5. 3. Myosin from the cardiac muscle of rabbit embryos reveals light chains of both fast and slow types, that from adult animals, however, reveals light chains of the slow type only. 4. These studies suggest that unlike the cardiac muscle of adult rabbit, cardiac muscle of rabbit embryos contains both fast and slow types of myosin.

Adenosine Triphosphatases↗
PubMed1979

Field study of the relationship between skin-sensitizing antibody production in the cottontail rabbit, Sylvilagus floridanus, and infestation by the rabbit tick, Haemaphysalis leporispalustris (Acri: Ixodidae).

The resistance of cottontail rabbits to tick feeding appears correlated with the rabbits' development of skin-sensitizing antibodies. Resistance appeared to be greatest in adult rabbits which had been repeatedly infested with ticks. Rabbits with little exposure to ticks, usually the young cottontails, showed little or no skin-sensitizing antibody present in their blood and usually had relatively high tick loads when compared with adult rabbits. Models used to interpret the data show promise as tools for predicting tick population fluctuations and, perhaps, incidence of vector borne disease outbreaks. The existence of resistance to tick attachment has important implications for the host-parasite relationship. The research lends support to the hypothesis that the resistance may function as a homeostatic regulatory mechanism capable of maintaining the size of the tick population in equilibrium with the size of the rabbit population. In this way, host resistance may be advantageous to the parasite as well as to the host.

Animals↗
PubMed1976

Prostaglandin endoperoxides, serotonin and the superfused rabbit aorta: possible pitfalls in the bio-assay of rabbit aorta contracting substance (RCS).

The specificity of the isolated rabbit aorta for identification and assay of prostaglandin endoperoxides, formed during aggregation of platelet rich plasma (PRP) from rats, was investigated in the superfused organ cascade. The use of cumulative dose-response curves in this design is quicker than conventional step-wise dosing while delivering identical results. On the rabbit aorta, in contrast to the rat fundus strip, methysergide is too weak an antagonist to rule out responses due to 5-HT. After pretreatment with phenoxybenzamine, in the presence of methysergide, the rabbit aorta retains its sensitivity towards oxygenated fatty acids, while being virtually unreactive towards 5-HT. The prostaglandin endoperoxide PGH2 is more potent than prostaglandin E2 when assayed on the rabbit aorta, while on the rat fundus the situation is reversed. Combining the rabbit aorta and rat fundus strip with pre-filtration on Amberlite XAD-2 columns showed that during collagen induced aggregation rat PRP generated both a labile RCS-most probably a prostaglandin endoperoxide- and a lipophylic prostaglandin-like material, along with 5-HT.

Animals↗
PubMed1977

Some electrical properties of the rabbit anococcygeus muscle and a comparison of the effects of inhibitory nerve stimulation in the rat and rabbit.

1. Simultaneous recordings of mechanical activity and membrane potential of individual smooth muscle cells have been made in the rabbit anococcygeus muscle and the effect of field stimulation on these examined.2. In the absence of tone the mean resting membrane potential was - 48 mV. In the stretched muscle spontaneous tone and rhythmic activity quite frequently appeared and this was associated with depolarization of the muscle cells.3. The response to field stimulation depended on the frequency of stimulation, the level of membrane potential and the presence of myogenic tone. The usual response to single pulses or low frequency stimulation was a hyperpolarization of up to 30 mV (mean 14+/-6.8 mV) after a latency of 185 msec and accompanied by muscle relaxation. Higher frequencies (over 8 Hz) produced an initial depolarization often with a spike potential and followed by hyperpolarization. The mechanical response in these instances was contraction or contraction followed by relaxation. At all frequencies rebound depolarization and an associated contraction followed the end of stimulation).4. Phentolamine (5x10(-6)M) and guanethidine (10(-6)M) blocked the initial depolarization and contraction but had no effect on hyperpolarization, muscle relaxation or rebound depolarization and contraction.5. The effect of field stimulation in the presence of guanethidine (4x10(-5)M) was re-examined in the rat anococcygeus. Single pulses were ineffective, repetitive stimulation produced muscle relaxation but no hyperpolarization comparable to the rabbit. Any oscillations in membrane potential were damped during field stimulation and sometimes a small hyperpolarization was produced with a maximum amplitude of 13 mV and a mean of 1.9+/-1.2 mV.6. The transmembrane potential at the peak of hyperpolarization in the rabbit was rarely more than -70 mV. Passive displacement of the membrane potential by current pulses altered the amplitude of the hyperpolarization and suggested that there was a reversal potential at between -80 and -90 mV.7. No change in input resistance could be measured during inhibitory nerve stimulation in either the rabbit or the rat but measurements based on electrotonic potentials indicated a reducation in membrane resistance, small in the rat but greater in the rabbit.8. These experiments suggest that in both species muscle relaxation is associated with an increase in ionic permeability and a move, at least in the rabbit muscle, towards an equilibrium potential of -80 to -90 mV. In view of the much smaller effect in the rat it is not clear whether this is the cause or at least the sole cause of the muscle relaxation.

Action Potentials↗
PubMed1979

Limited protection of rabbits against infection with Treponema pallidum by immune rabbit sera.

After intradermal infection of rabbits with 3 x 10(6) Treponema pallidum (Melbourne 1 strain) samples of serum were taken at one, two, three, four, and six months after infection. Normal rabbits were passively immunised with these sera, challenged with intradermal doses (10(4), 10(3), 10(2), 10) of T. pallidum, and the latent periods of infection, lesion diameters, and the number of inoculation sites developing into lesions were observed. The sera taken at three, four, and six months reduced the number of intradermal inoculation sites that developed into syphilitic lesions after challenge with 10 T. pallidum. These same three sera also increased the latent period of infection after challenge with 10(4) T. pallidum. The transfer of 50 ml of immune serum per rabbit over a nine-day period before challenge had very little effect on the course of the challenge infection. Only a low level of immunity in rabbits to this strain of T. pallidum appears to be mediated by immune serum but this small degree of protection did increase with time after infection. Enhanced growth of T. pallidum in the serum-recipient rabbits did not occur, thus suggesting that none of the sera was immunosuppressive.

Animals↗
PubMed1978

Rabbit acrosin: immunological dissimilarity to rabbit trypsin (1).

Antibodies obtained from guinea pigs injected with rabbit pancreatic trypsin together with antibodies raised in rabbits against bovine acrosin or bovine pancreatic trypsin were reacted against various mammalian trypsins and acrosins in double diffusion tests. The results of immunodiffusion analyses reveal antigenic dissimilarity between rabbit acrosin and rabbit trypsin.

Acrosin↗