Commercial Rabbit Research Articles

Carcinoembryonic antigen like antigen in granular cell myoblastomas

A series of granular cell myoblastomas (GCM) and other benign and malignant tumours of soft tissue were examined for cytoplasmic content of carcinoembryonic antigen (CEA) by the two-layer conjugated immunoperoxidase technique. Using a commercial rabbit anti-CEA serum only granular cell myoblastomas showed positive cytoplasmic reaction. Pretreatment with periodic acid made this reaction less intense, but when the commercial rabbit anti-CEA serum was absorbed with tissue powder from normal human spleen the positive reaction was totally abolished. It is concluded that the positivity of GCM for CEA using commercial rabbit anti-CEA serum is due to the content of non-specific cross-reacting antigen (NCA) and maybe other cross-reacting glycoproteins in this tumour, and not to CEA as claimed in a previous study.

The effect of polyunsaturated fatty acids of the n-3 and n-6 series on platelet aggregation and platelet and aortic fatty acid composition in rabbits

Four groups of 6 New Zealand white rabbits were fed for 60 days on a commercial rabbit diet supplemented (60 g/kg) with 1 of 4 sources of fat: corn oil, linseed oil and fish oil, which respectively provided rich sources of linoleic acid (C18:2, n-6), α-linolenic acid (C18:3, n-3) and eicosapentaenoic acid (C20:5, n-3), and coconut oil, low in all polyunsaturated fatty acids (PUFA). Platelet-rich plasma was prepared and aggregation induced by ADP (final concentration 0.29–74.3 μM), collagen (2.5–20 μg/400 μl, final concentration) and 2.5 U bovine thrombin, and recorded with a Peyton aggregometer. Platelet aggregation induced by both thrombin and collagen was significantly lower with either n-3 PUFA (fish or linseed oil) than with corn oil (n-6 PUFA) or the low PUFA coconut oil. ADP-induced platelet aggregation was significantly reduced only in animals fed fish-oil. Changes in platelet aggregation were accompanied by increased platelet lipid content of C20:5, n-3 and decreased content of C20:4, n-6, with little change in platelet total C20 fatty acids. Platelet levels of C20:5, n-3 were significantly increased with both the performed C20:5, n-3 and its precursor C18:3, n-3 in the diet. However, aortic lipid accumulation of C20:5 only occurred with rabbits fed on fish oil. It was concluded that, for collagen and thrombin induced aggregation, C18:3, n-3 and C20:5, n-3 were equally anti-aggregatory in rabbits. The implications of this in community nutrition programmes are discussed.

Reduction of casein-induced hypercholesterolaemia and atherosclerosis in rabbits and rats by dietary glycine, arginine and alanine

We have studied the effect of amino acid supplementation on the hypercholesterolaemia and atherosclerosis caused by cholesterol-free casein-containing diets in rabbits, and on the hypercholesterolaemia caused in rats by diets containing casein plus added cholesterol. Five groups of rabbits each received for 48 weeks semi-purified diets containing casein as a protein source. In one group the animals received additional arginine and alanine, and in three other groups the diets were supplemented with arginine, alanine and three different levels of glycine. These supplementations were chosen so as to bring the amino acid composition of the diets closer to that of commercial rabbit pellets. Average body weights at the end of the experiment were 3400 g in the casein group and 3800–3900 g in the four amino-acid-supplemented groups. Average serum cholesterol levels over the last 10 weeks were 15.7 mmol/l for the casein group, 12.0 for the casein-arginine-alanine group and 8.5, 8.8 and 8.1 for the three groups receiving arginine, alanine and increasing amounts of glycine. Serum cholesterol concentrations in the combined glycine-receiving groups were significantly lower than in the unsupplemented casein group. At the end of the experiment aortas were dissected from all rabbits and the sudanophilic surface area was quantitated. The extent of aortic sudanophilia was less in the amino-acid-supplemented groups than in the casein group. There was a strongly significant correlation between the proportion of aortic surface covered by sudanophilic plaques and the serum cholesterol concentration per animal. The effect of dietary glycine was not limited to rabbits: when we fed rats semi-purified diets containing cholesterol, and casein, casein plus glycine, or soy isolate, we obtained mean serum cholesterol levels of 10.4 mmol/l in the casein group, 4.9 in the casein-plus-glycine group and 3.5 in the soy group. We conclude that casein-induced hypercholesterolaemia and its sequelae are partly relieved by addition of glycine to the diet, while supplementation of casein-based rations with arginine and/or alanine may be necessary for rabbits. However, the beneficial effects of these amino acids could just as well be explained by the presence of an excess of other amino acids in casein (amino acid imbalance) as by an absolute shortage of glycine, arginine or alanine.

Immunoperoxidase staining of carcinoembryonic antigen with monoclonal antibodies in adenocarcinoma of the colon.

Mouse monoclonal antibodies to carcinoembryogenic antigen (CEA) obtained by the somatic cell hybridization technique of Köhler and Milstein were used in a modified enzyme bridge immunoperoxidase staining method. Both high and low affinity antibodies were tested and their staining properties compared with those of a commercial polyvalent rabbit antiserum. The staining pattern of neoplastic epithelial cells in all seven antibodies in samples of primary adenocarcinoma of the colon was similar, indicating that no gross differences were found in the exposure of the different antigenic determinants of CEA in formalin fixed tissue. The background staining of the monoclonal antibodies are negligible. It is concluded that monoclonal antibodies are superior to conventional antisera in immunoperoxidase staining of CEA.

Culture-generated suppressor cells: Evidence for an adherent cell component

Cells which suppress mixed lymphocyte reaction (MLR) and cytotoxic T-lymphocyte (CTL) generation can be demonstrated after culture for 3 to 5 days in the absence of added antigen. Such precultured suppressors are resistant to the cytotoxic effects of commercial rabbit anti-mouse brain serum, congenic anti-Thy-1.2 serum, and monoclonal anti-Thy-1.2 reagent. In addition, these cells, which adhere to both nylon wool and Sephadex G-10, ingest carbonyl iron. These properties suggest that precultured suppressors may not be thymus-processed. Precultured suppressor cells, when irradiated, are able to suppress only the MLR, and not the generation of allo-CTL. This finding, taken with our previously published work on the differential ontogeny of cells which suppress the MLR or CTL generation in culture, suggests that at least two kinds of suppressors are generated. One suppressor acts on CTL generation, is radiosensitive, and develops late in ontogeny; the other suppressor acts on proliferative cells in the MLR, is radioresistant, and develops early in ontogeny. Both kinds of suppressors, however, are adherent to nylon wool and Sephadex G-10, ingest carbonyl iron, and are resistant to anti-T-cell sera.

豚における血清C-反応性蛋白様物質陽性率

The rate of swine positive for C-reactive protein (CRP)-like substance in serum was examined. It was 84% in 50 hogs raised on general farms, 52% in 25 hogs reared on hog farms, 55% in 20 secondary SPF pigs, and 47.6% in 21 piglets on general farms when determined by the capillary precipitation method with commercial anti-CRP rabbit serum for human use. There was a tendency for the positive rate and the grade of positivity to be low on farms showing low microbial contamination.The positive rate was high in swine with renal hemorrhage, pneumonia, gastritis, enteritis, epicarditis, and septicemia. It was low in swine with lesions restricted to a single organ and high in those with lesions spread over the lung and kidney or more than two other organs.

Determination of Canine Factor VIII-related Antigen Using Commercial Antihuman F VIII Serum.

Factor VIII-related antigen (F VIII:AGN) in 21 canine plasma samples was assayed by immunoelectrophoresis using a rabbit anticanine F VIII serum prepared from a canine F VIII concentrate and a commercial rabbit antihuman F VIII serum. A good correlation existed (r value 0.916) between the antigen levels obtained using the two sera. In normal dogs the plasma F VIII:AGN level was 95 +/- 39% (Mean +/- SD) compared to 175 +/- 40% in dogs with severe hemophilia A and 17 +/- 15% in dogs with von Willebrand's disease. It was concluded that there was sufficient cross reactivity between canine F VIII and commercial rabbit antihuman F VIII serum to make the latter useful in the differential diagnosis of F VIII deficiencies in the dog.

The effects of glibenclamide on lipid content of the aorta and plasma lipoprotein in normal rabbits.

The study was performed on 12 male rabbits, which were divided into two groups; one group of 7 rabbits fed on commercial rabbit pellet mixed with 2 mg of glibenclamide per kg of the food (G-group), and the other of 5 rabbits fed on rabbit pellet only without mixing glibenclamide as the control group (C-group). The food intake was limited to 200 g daily. Three months later, the blood was collected from these rabbits in fasting state for determination of blood sugar and IRI, and lipoprotein analysis. Then, the aorta was taken out for determination of cholesterol and cholesterol ester. There was no significant difference between both groups in terms of weight gain, blood sugar and IRI, while cholesterol content in the aorta of G-group (2.68±0.12 mg/g wet weight) was significantly higher (p<0.05) than that of C-group (2.28±0.12 mg/g wet weight). HDL-cholesterol level was similar in both groups, while LDL-cholesterol of G-group (10.8±2.3 mg/100 ml) was higher than that of C-group (7.3±1.5 mg/100 ml). These results suggest that glibenclamide may have atherogenicity in normal rabbits probably because of an increment of LDL-cholesterol.

Cross-Species Contamination of Commercial Serum Proteins

Abstract Dear Sir: After being plagued for some time by uninterpretable results in our radioimmunoassays, we began to suspect that the source of error could be the presence of bovine albumin in the preparations of commercial rabbit γ-globulin used in controls. Indeed, this unlikely contaminant was easily demonstrated by crossed immunoelectrophoresis and double immune diffusion in agarose in five out of five lots of rabbit γ-globulin, in one out of two preparations of rabbit albumin, and in the single sample of mouse immunoglobulin that was tested.1 Furthermore, we isolated bovine serum albumin from commercial rabbit immunoglobulin by anion exchange chromatography. By rocket immunoelectrophoresis we estimated the degree of contamination to be between 0.2 and 0.5%. Sixteen years ago it was reported in Science (142: 1170, 1963) that bovine albumin could be detected in some lots of commercial rabbit albumin.

正常ウサギの大動脈壁脂質およびリポ蛋白脂質に及ぼすインスリンの影響

The effect of insulin on a lipid content of the aorta and lipid distribution of the lipoprotein was studied in normal rabbits.The study was performed on 12 male rabbits, being divided into two groups; one group (7 animals) was injected long acting insulin (1 unit/kg daily) (insulin-group) and the other (5) was used as control (control-group). The food (commercial rabbit pellet) intake was limited 200g daily.Three months later, the blood collected in the fasting state for the determination of blood sugar, IRI and lipoprotein, thereafter the aorta was removed for the determination of cholesterol (Ch) and cholesterol ester (Ch-E) in the wall of the aorta.There were no significant differences between two groups in weight gain, blood sugar and IRI. Ch content in the aorta was higher in insulin-group (2.96±0.28mg/g wet weight) than in controlgroup (2.28±0.12mg/g wet weight), though the difference was not significant. Ch-E content in the aorta was higher in insulin-group than in controlgroup, too. HDL-Ch levels were similar in two groups. LDL-Ch levels in insulin-group (12.8±1.4mg/dl) were significantly higher (p<0.05) than that in control-group (7.3±1.5mg/dl).As a result of this study, it is suggested that insulin may have atherogenic action in the normal rabbit, probably by means of an increment of LDL-Ch.

Diseases of the commercial rabbit.

Throughout its short history, the commercial rabbit industry has suffered from a poor home market due to the long national memory of the 1950s myxomatosis outbreak, the strong competition from the broiler chicken industry and of low-priced imported rabbit. In the past few years, a new market for British rabbit has opened up in Europe with a potential demand far in excess of the present production. The veterinary profession can assist in this expansion.

Snowshoe Hare Population Response to Artificial High Densities

Demographic response of snowshoe hare ( Lepus americanus ) populations to artificial high densities was studied during summer and autumn near Rochester, Alberta. Experimental populations were established by transplanting hares onto islands in lakes in May and June. High-density populations on Dapp Island (15.4 hectares) in 1970 and Birch Island (3.6 hectares) in 1971 were adversely affected by food shortages. Rates of pregnancy and adult survival rates in these high-density populations did not differ from unmanipulated natural populations near Rochester, but juvenile survival was markedly lower. In 1972, a fence was constructed across Birch Island to separate two introduced high-density populations. One was supplementally fed commercial rabbit pellets ad libitum and the other was forced to subsist on an insufficient quantity of native vegetation. Again, survival among adults was comparable in the fed and unfed high-density island populations and unmanipulated populations at lower densities. Pregnancy rates were lower and no young were found in the unfed island population. In comparisons with low-density Rochester populations, no adverse demographic responses such as reduced pregnancy or higher juvenile mortality was recorded in the fed high-density population. The high disappearance rate of juveniles from all high-density populations with limited food appeared to have been directly linked to food scarcity which affected young more severely than adults. We could find no evidence that either parasitic or viral diseases, or social stresses, as indexed by incidence of scarring and adrenal weights, were acting as direct mortality factors in the food-limited high-density experimental populations.

Thyroid hormone and experimental atherosclerosis in rabbits

Rabbits were fed a diet containing 2% added cholesterol but no fat for 60 days. When the diet contained D-thyroxine (0.5 mg/day) or L-thyroxine (0.05 mg/day) both serum cholesterol and atheromata were lower than they were in control rabbits. Of 10 studies in the literature relating to thyroid hormone and atherosclerosis, 7 report reduced atherosclerosis and 3 report increased atherosclerosis in drug-treated rabbits. The data are collected and the suggestion made that some ingredient present or absent in commercial rabbit ration may be responsible for the reported effects.

Reduction of the hypoxia-induced depression in the intracellular electrical activity of the ventricular muscle fibers of the rabbit fed on food containing Crataegutt.

The rabbits were divided at random into 2 groups: one was fed for 6 weeks on the rabbit food containing 5 mg Crataegutt per 100 Gm food (CR group), and the other was fed for the same period on the commercial rabbit food and used as a control. Intracellular records were made from fibers in the ventricle of isolated rabbit heart. The inhibitory influences of hypoxia on the resting membrane potential and on the amplitude of action potential of the fiber of the CR group are significantly less than those of the control group. However, the inhibitory influence on the time courses of contraction of the papillary muscle was almost the same between these 2 groups.

Prothrombin Determination by Means of a Chromogenic Peptide Substrate

A two stage method to determine prothrombin with the chromogenic peptide substrate benzoyl-phe-val-arg-p-nitroanilide has been worked out. Citrated plasma (10 mul) was diluted in 600 mul tris buffer, pH 8.2, ionic strength 0.18 and activated with 250 mul of a commercial rabbit brain-lung thromboplastin. After 325 s incubation at 37 degrees C 200 mul of a 1 mM solution of the chromogenic substrate was added and the increase in absorbance was recorded in a LKB-Beckman 8600 enzyme analyzer. A reading time of 1 minute (including a delay of 20 s) was used which permitted 55 analyses per hour to be carried out. An approximate linear relationship was found between delta A/min and dilutions of normal plasma in prothrombin deficient plasma. The method is insensitive to variations of factors V, VII and X. Less than 10% or normal plasma was needed to "normalize" plasmas deficient in factor V or VII or X. A group of 99 dicoumarol treated patients and 23 normal subjects has been investigated using the present method and compared with a factor II-VII-X determination method. A correlation coefficient of 0.95 was found.

Aufzucht und Ablaichen von Siganiden (Pisces: Teleostei) in einem geschlossenen Seewasserkreislauf

1. Two species of signaids from The Philippines,Siganus oramin andS. concatenata (S. guttatus?), were reared in a closed sea water system and fed different artificial feeds. 2. A comparison between commercial chicken and rabbit feeds in regard to their suitability as siganid feeds led to the conclusion that for this purpose the latter was the more appropriate diet. 3. Within six months juvenileS. oramin (4–6 cm, 2–6 g) reached maturity and were treated with human chorionic hormone (HCG) in order to induce ovulation. 4. Two females were successfully stripped after having received HCG injections. The eggs were artificially inseminated and incubated at 15.8, 20.9, 30.6 and 32.2‰ S. 5. Early embryogenesis was evaluated by means of time lapse movie pictures (two frames/min). 6. Incubation of the eggs at 26°–28° C took 29 h from fertilization to hatching. Viable larvae hatched only between 20.9 and 32.2‰S and larval survival was best in 32.2‰S. There was no viable hatch at 15.8‰S, and no fertilization occured at 12.1‰S.

Normal values for some biochemical constituents in rabbits.

54 Belgian semi-lop rabbits from aclosed colony were used for the experiment. Environmental effects were minimised by employing a 12 h light cycle in a room thermostatically maintained at 17-] 8°C. The rabbits were equilibrated for 6 weeks before blood samples were taken when 12-14 weeks old and 2-2' 5 kg bodyweight. They were fed on standard commercial pelletted rabbit food (BOCM Silcock Ltd, Basing View, Basingstoke, RG21 2EQ) with anticoccidiosis supplement, based on Diet 18 (Bruce & Parkes, 1947). Food and water were allowed on demand but food was withheld from 1730 on Wednesdays. Samples were collected at 0900-1030 on Thursdays, immediately before cage cleaning. Cages were also cleaned on Monday mornings. Blood samples were collected from the marginal ear vein after dilatation with an infrared lamp, and treated with sequestrene anticoagulant (Turner-Stayne Products, York House, Empire Way, Wembley, HA9 OPS) and plain tubes. A single sample of 8-10 cm 3 was taken from each of the 54 rabbits. Labile component analysis was performed within 2 h and the serum separated. Analysis of other components was performed within 48 h of collection, the serum being stored at -20°C. All analyses were performed in duplicate and the mean taken. Estimations were controlled with commercial quality control serum as far as possible and the statistical parameters calculated with a computer (Table I).

Sub-lethal Effect of Sulphaquinoxaline on the Tsetse Fly, Glossina austeni Newst

A MARKED fall in fecundity of females of the tsetse fly, Glossina austeni Newst, fed on rabbits, was found to be associated with the use of a commercial rabbit diet containing, as a coccidiostat, 75 p.p.m. sulphaquinoxaline and 7.5 p.p.m. pyrimethamine. Contemporary flies fed on goats reproduced normally.

Prenatal Growth of the Cottontail Rabbit in South Texas

This paper reports a study of prenatal growth of cottontail rabbits on the Welder Wildlife Refuge in South Texas. Measurements of known-age cotton- tails showed that the young in utero were smaller than Missouri rabbits of the same ages. However, they were similar in size at birth. A prenatal curve was fitted by hand for crown-rump length; hind foot length and body weight data were also pre- sented. In a study of the population ecology of cottontails on the Welder Wildlife Refuge in South Texas (Bothma and Teer, in press), it was necessary to develop a prenatal growth curve for use in determining conception dates for litters in utero. Since no prenatal growth curves have been developed for cottontails specifically, an attempt was made to do so. The Welder Wildlife Refuge falls within the range of Sylvilagus flor'danus chapmani, but it was apparent that intergrades between S. f. chapmani and S. f. alacer occurred. Hall and Kelson (1959) recog- nize a zone of integradation of chapmani and alacer in South Texas. The Welder Wildlife Refuge lies near this zone. Nonetheless, the char- acters of habitat and coat color are more closely related to chapmani. MATERIALS AND METHODS. A series of 6 covered pens, each 25 ft x 50 ft x 5 ft high, were used. The pens had natural vegetative cover, and were provided with brush and artificial shelters. Commercial rabbit pellets and water were always freely available. A series of males and females were trapped in the field, and the sexes were kept in separate pens for a minimum of 30 days. Since the gestation period of the cottontail rabbit is about 28 days (Lord, 1963), this confinement in-

Enzyme histochemical observations on the effect of pyridinol carbamate on cholesterol-induced atherosclerosis

The effect of pyridinol carbamate on cholesterol-induced atherosclerosis in the rabbit was investigated in 28 animals. The diet was given for 8 months. The effect of pyridinol carbamate on lactate-NAD-tetrazolium reductase and ATPase activities of the abdominal and thoracic aortae was examined histochemically. The animals were divided into 4 dietary groups: 1. 1. regular diet (commercial rabbit food pellets, Orion) 2. 2. regular diet + pyridinol carbamate (100 mg/kg) 3. 3. regular diet + cholesterol (1 %) 4. 4. regular diet + cholesterol (1 %) + pyridinol carbamate (100 mg/kg). Lactate-NAD-tetrazolium reductase and ATPase were identical in the samples taken from the thoracic and abdominal aortae in all groups. No atherosclerotic formation was noted in dietary groups 1 and 2. Lactate-NAD-tetrazolium reductase and ATPase activities were identical in these two groups. Pyridinol carbamate was not observed to have any effect on lactate-NAD-tetrazolium reductase and ATPase activities of the aorta and atheroma plaques of the rabbit.