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[Antilithogenic action of dehydroxymaleic, ketomalonic (mesoxalic) and tartronic acids in relation to experimental lithiasis in rats].

The authors study the effects of three acids, one with four carbon atoms, dihydroxymaleic acid, the two others with three carbon considered atoms, ketomalonic acid and tartronic acid. A first study considered the effects of these products on experimental lithiasis induced by oxalic acid, glyoxylic acid and ethylene-glycol. Dihydroxymaleic acid. Monohydrate calcium oxalate stones can be easily induced in the male rat, with in 24 hours, by an intraperitoneal injection of oxalic acid, at the rate of 8 mg per 100 g of body weight. If 25 mg of dihydroxymaleic acid are injected simultaneously via the intraperitoneal route, to a rat weighing 150 g, the lithiasis observed after 24 hours is just as severe. Experimental monohydrate calcium oxalate lithiasis is also induced by intraperitoneal injection of 8 to 9 mg of glyoxylic acid in a 100 mg rat. Dihydroxymaleic acid, injected at the same time as glyoxylic acid, also via the intraperitoneal route, at the rate of 50 mg for a rat weighing 150 g, results in total suppression of the lithiasis. Dihydroxymaleic acid also prevents lithiasis induced by the absorption by the rat, for several weeks, of a 1% ethylene-glycol solution if it is mixed to this solution at the rate of 5 mg per ml. A 12% ethylene-glycol solution given to the rat at the rate of 0.55 ml for 100 g of body weight induces the next day a comatose state and a diffuse parenchymatous monohydrate calcium oxalate lithiasis: coma and lithiasis are prevented by the simultaneous absorption of dihydroxymaleic acid at the rate of 65 to 70 mg. The ketomalonic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Adjuvant and immunostimulatory effects of beta-glucan administration in combination with lipopolysaccharide enhances survival and some immune parameters in carp challenged with Aeromonas hydrophila.

Combined effects of beta-glucan and lipopolysaccharide (LPS) on survival and immune response were studied in Cyprinus carpio that were challenged with the pathogen Aeromonas hydrophila. beta-Glucan from Saccharomyces cervisiae and LPS from a virulent strain of A. hydrophila were used in this study. Different concentrations of beta-glucan+LPS mixture were administered on days 1, 7, and 14 through different routes (intraperitoneal injection, bathing, and oral administration). Control and test fish were challenged by intraperitoneal injection of LD50 concentration of A. hydrophila on day 16 and subsequently, mortality and relative percent survival (RPS) were recorded. Intraperitoneal injection elicited 100% RPS even at the lowest concentration (100 microg beta-glucan+10 microg LPS); whereas, oral administration improved RPS rate of carps at higher concentration (1% beta-glucan+0.25% LPS). Bathing did not improve the RPS. Test animals injected with even the minimum dose of the immunomodulators (100 microg beta-glucan+10 microg LPS/fish) had a significant increase in total blood leukocyte counts and an increase in the proportion of neutrophils and monocytes. Superoxide anion production by macrophages was also elevated, which presumably aided the efficient killing of bacterial pathogen. Lower concentration of beta-glucan+LPS had an adjuvant effect on antibody production as pretreatment by injection of 100 microg beta-glucan+10 microg LPS/fish resulted in higher antibody titer against A. hydrophila following vaccination. RT-PCR analyses showed that the expression of interleukin-1beta mRNA did not increase in test fish when compared with the control. Classical and alternative complement pathways were not affected by either the dose or the route of administration of the compounds. It may be concluded that intraperitoneal injection and oral administration, and not the bathing, of beta-glucan+LPS mixture in carp could enhance resistance to challenge by A. hydrophila through changes in several non-specific and specific immune responses.

Adjuvants, Immunologic↗

Evaluation of iron dextran and mucin for enhancement of the virulence of Yersinia enterocolitica serotype O:3 in mice.

The pathogenic role of Yersinia enterocolitica serotypes O:3, O:8, and O:9 in human infections is well documented. Whereas the virulence of the O:8 strains can be readily demonstrated in mice by 50% lethal dose determinations, the O:3 and O:9 strains have no lethal effect on mice by any route of inoculation. A mouse virulence test for the O:3 and O:9 strains is described. Y. enterocolitica strains were first tested for the presence of virulence-associated plasmid characteristics by auto-agglutination and gel electrophoresis procedures before mouse virulence determinations. The 50% lethal dose of the O:3 strains injected intraperitoneally with 2.5% mucin was about 10(7) colony-forming units. However, histological examinations showed that mucin allowed the growth of Y enterocolitica on the surface of the livers and spleens of the mice without internal lesions. The 50% lethal dose of the same O:3 strains injected intraperitoneally with 1 ml of 10% iron dextran in saline was about 10(5) to 10(6) colony-forming units, and the nonlethal infective dose with typical lesion development was 20 to 200 colony-forming units. The infected mice developed symptoms and extensive liver and spleen lesions which differed from those in mice infected intraperitoneally with the virulent O:8 strains. These results showed that the virulence of the O:3 Y. enterocolitica strains can be measured by intraperitoneal injection with iron dextran. This procedure was used to test the virulence of food isolates, plasmidless strains, and the effect of growth temperatures.

Agglutination↗

Acute ethanol intoxication inhibits neutrophil beta2-integrin expression in rats during endotoxemia.

The effects of acute ethanol intoxication on neutrophil [polymorphonuclear leukocyte (PMN)] adhesion molecule expression and certain other functional properties during endotoxemia were studied in rats to elucidate the mechanisms underlying the immunosuppressive effects of ethanol. Acute ethanol intoxication was induced by an intraperitoneal injection of 20% ethanol at a dose of 5.5 g of ethanol/kg. Control animals received an intraperitoneal injection of saline. Thirty minutes after intraperitoneal injection, animals were given a 90-min intravenous infusion of Escherichia coli endotoxin (total dose of 112.5 microg/rat in 2.5 ml of saline) or saline. Certain rats received granulocyte colony-stimulating factor (G-CSF; 50 microg/kg in 5% dextrose, subcutaneous injection twice daily) or vehicle pretreatment for 2 days before intravenous endotoxin infusion. Endotoxemia significantly upregulated CD11b/c and CD18 expression on PMNs when compared with those of saline-infused rats. Acute ethanol intoxication inhibited this endotoxin-induced upregulation of CD11b/c and CD18 expression on PMNs. Ethanol intoxication also suppressed the phagocytic activities of PMNs in saline-infused rats, but this suppression failed to reach statistical significance in endotoxin-infused rats. Hydrogen peroxide generation by PMNs in saline- or endotoxin-infused rats was not affected by ethanol intoxication. Histological examination showed extensive PMN sequestration in the liver after endotoxin infusion, and ethanol intoxication significantly attenuated this hepatic sequestration of PMNs. G-CSF pretreatment enhanced neutrophil phagocytosis, CD11b/c and CD18 expression in endotoxin-infused rats, and prevented the ethanol-induced inhibition of neutrophil CD18 expression and phagocytosis. The impairment of beta2-integrin expression on PMNs may be one mechanism underlying ethanol-induced defects of neutrophil delivery into tissue sites of infection. G-CSF may be of benefit to the infected alcoholic host by enhancing leukocyte defense functions.

Alcoholic Intoxication↗

[Effect of calcium channel blockers on temperature in mice].

In the experiments on SHR mice, verapamil, nifedipine, cinnarizin, fendilin, diltiazem, and nimodipine were tested for their effects on changes in rectal temperatures after intraperitoneal and intracerebroventricular injections. Intraperitoneal nifedipine (2 and 10 mg/kg), fendilin (5 and 20 mg/kg), and cinnarizin (5 and 50 mg/kg) lowered rectal temperatures. The similar effects were shown by nimodipine (2.4 micrograms), diltiazem (100 micrograms), and verapamil (100 micrograms) after their intracerebroventricular injections. It is concluded that the hypothermal effect of calcium antagonists is based on their central and hemodynamic mechanisms.

Animals↗

Effects of alpha- and beta-adrenergic antagonists on rise in body temperature induced by psychological stress in rats.

We investigated the effects of intraperitoneal injection of alpha- and beta-adrenergic antagonists on psychological stress-induced responses in free-moving rats. Psychological stress was induced by immersion in 2-cm-deep water. The intraperitoneal injection of the alpha-adrenergic blocker, phentolamine (10 mg/kg), attenuated the stress-induced rise in body temperature and hypertension but enhanced tachycardia. In contrast, intraperitoneal injection of the beta-adrenergic blocker, propranolol (1 mg/kg), suppressed tachycardia but had no effect on rise in body temperature and hypertension during stress. The intraperitoneal injection of both blockers had no effect on the increase in metabolic rate (O2 consumption) induced by stress. The intravenous injection of propranolol (1 mg/kg) suppressed the stress-induced rise in body temperature. We then examined the effect of intracerebroventricular injection of propranolol on the stress-induced rise in body temperature and found that intracerebroventricular injection of propranolol (50 micrograms) suppressed the stress-induced rise in body temperature. These results support the following hypotheses: 1) Systemic injection of phentolamine suppresses the psychological stress-induced rise in body temperature by facilitating heat-loss; 2) Peripheral beta-adrenergic stimulation probably does not contribute to psychological stress-induced rises in body temperature; and 3) central beta-adrenergic receptors are important in stress-induced increases in body temperature.

Adrenergic alpha-Antagonists↗

Effect of endotoxin on portal hemodynamic in rats.

AIM: To study the effects of endotoxin on portal hemodynamic of normal and noncirrhotic portal hypertensive rats. METHODS: Normal rats were intraperitoneally injected with 0.1, 0.25, 0.5, 1.0, 2.0, 4.0mg.kg(-1) of lipopolysaccharide(LPS) respectively, portal vein ligation(PVL) and intrahepatic portal occlusion (IPO) rats as well as sham-operated rats were treated with an intraperitoneal injection of 1.0mg.kg(-1) of LPS, the portal vein pressure(PVP), portal venous flow(PVF), inferior vena cava pressure(IVCP) and portal vein resistance(PVR) were detected 4 hours after injection. RESULTS: PVF of the 5 groups of rats accepting intraperitoneal injection of LPS were increased from 14.0 to 18.0, 22.2, 26.2, 34.8, 39.6, 38.8 mL.min(-1) 4 hours after injection of LPS(P<0.01). PVP of the 4 groups of rats accepting more than 0.1mg/kg.b.w of LPS was increased from 1.04 to 1.25, 1.50, 1.80, 1.95, 2.05 kPa(P<0.01). The increments of PVF and PVP were in a dose-dependent manner of LPS. PVR of the 5 groups of rats was decreased from 51 to 42,44,48,45,44,47 kPa.min.L(-1) (P<0.05) and no dose-dependent manner was observed. PVF of PVL, IPO and sham-operated rats increased from 22.6 to 32.8, 22.0 to 28.0, 14.0 to 34.8 mL.min(-1) (P<0.01), and PVP increased from 1.86 to 2.24, 1.74 to 1.95, 1.04 to 1.80 kPa(P<0.01), PVR decreased from 71 to 61, 67 to 61, 52 to 44 kPa.min.L(-1) after intraperitoneal injection of 1mg.kg(-1) of LPS. The increments of PVF and PVP of PVL and IPO rats were significantly less than the sham-operated rats(P<0.01), There was no significant difference between the amounts of PVR decreased in the two groups of PHT model rats and sham-operated rats(P>0.05) after intraperitoneal injection 1mg.kg(-1) of LPS. CONCLUSION: Endotoxin could prompt portal hypertension of the normal and noncirrhotic portal hypertensive rats by increasing portal blood flow mainly.

Animals↗

In vitro tumor cell killing by peritoneal macrophages from mitomycin C-treated rats.

The local cellular response induced by intraperitoneal injection of mitomycin C was examined in terms of cell-mediated cytotoxicity for tumor cells. An in vitro cytolysis assay involving 125I-iododeoxyuridine-labeled tumor target cells revealed that treatment of normal ACI/N rats (200 g) with a single intraperitoneal injection of mitomycin C (50, 100, or 200 micrograms) induced tumoricidal macrophages in the peritoneal cavity. The tumoricidal activity was dependent on the dose of mitomycin C injected and it was detectable as early as 1 day after the intraperitoneal injection of mitomycin C. In addition to the increased tumoricidal activity, the functional activities of the peritoneal macrophages were found to be increased with respect both to uptake of 2-deoxy-D-glucose and to phagocytosis of latex beads. Additional experiments excluded the possibility that the tumor cell cytolysis was the result of direct cytotoxicity by mitomycin C that might have been incorporated in the peritoneal macrophages or of nutrient depletion in the medium during the cytolysis assay. Furthermore, endotoxin contamination of the mitomycin C, which might have produced the activated macrophages, was not detected. The mechanism by which mitomycin C injected intraperitoneally induced the tumoricidal macrophages locally remains uncertain; however, it is possible also in clinical situations.

Animals↗

Impaired clearance of Escherichia coli bacteremia in early biliary obstruction.

Adult male rats underwent common bile duct ligation or sham celiotomy. At intervals of 7 and 14 days postoperatively, bacteremia was induced by intravenous injection of 10(9) Escherichia coli or intraperitoneal injection of 10(6) E. coli. Serial quantitative blood cultures and quantitative whole organ cultures were obtained. One week after surgery, clearance of bacteremia was impaired in all of the animals. Clearance of intraperitoneally injected E. coli was less efficient in the duct ligation rats. Fourteen days postoperatively, clearance of bacteremia induced by intravenous or intraperitoneal injection had improved in the sham celiotomy rats but was still significantly impaired in the duct ligation rats. An increased number of viable E. coli were recovered from the lungs of duct ligation rats after intravenous administration. We found that rats with obstructive jaundice do not respond normally to a bacteremia challenge. This impairment in reticuloendothelial function can be noted as early as 1 week after common duct ligation.

Animals↗

The effects of humoral, cellular and non-specific immunity on intracerebral Bordetella pertussis infections in mice.

When mice were injected intracerebrally with doses of Bordetella pertussis vaccine greater than 5 ImD 50 and challenged intracerebrally 14 days later with virulent B. pertussis there was an immediate reduction in the numbers of organisms. An analysis of this in vivo bactericidal effect has shown that large doses of an unrelated vaccine, Salmonella typhosa, equivalent in cell mass to about 50 ImD 50 of B. pertussis vaccine can achieve this effect, so for such doses the effect must be partly non-specific. This action is not maintained and so is not ultimately protective. Local immunoglobulin was also demonstrable 14 days after 300 ImD 50 of B. pertussis vaccine but following smaller doses of 10-20 ImD 50 it could not be found until after the mice had been infected and the blood-brain barrier impaired. A similar immediate reduction in the numbers of infecting organisms inoculated 1 day after vaccination has been shown to follow very small, non-protective doses of vaccines unrelated to B. pertussis and to be achieved with lipopolysaccharide and endotoxin isolated from B. pertussis. Brains were not sterilized and only in mice receiving protective B. pertussis vaccine was the lowering of infection maintained beyond 2 days and the brains eventually sterilized. The antibody passively protecting mice against intracerebral infection was found in the 19S and 11 S globulin fractions of the serum of once-vaccinated mice and in the 11 S and 7 S fractions of the serum of rabbits and ascitic fluid of mice receiving repeated doses of vaccine. The IgM probably eliminated infections by immediate sterilization but had to be present locally to do so since it was unable to pass from the circulation into the brain, and was therefore inactive when injected intraperitoneally. The IgA and IgG were not so restricted and both the 11 S and 7 S globulins were capable of exerting an immediate suppressive effect on infecting organisms. The 7 S globulin was also capable of a maintained or delayed suppressive effect. Lymphocytes from fully protected once-vaccinated mice, transferred 2-3 weeks after intraperitoneal vaccination, were able to confer some protection when injected intraperitoneally or intracerebrally into recipient mice infected 2 weeks after transfer. Homologous, non-concentrated antiserum from once-vaccinated mice, injected intraperitoneally 1 hr. before infection sometimes augmented the transferred immunity, whereas alone it was inactive.

Animals↗

Elevated blood glucose levels and satiety in the rat.

Thirteen rats were placed on a feeding schedule of two 3 hr periods of food availability daily. blood glucose levels of the experimental animals were altered by intraperitoneal injection of 8 ml of 2, 5, 8, 12, 16, 20 and 25 percent glucose solutions and by intragastric loading of 8 ml of 25, 50 and 65 percent glucose solutions in 10 different feeding experiments. In 4 additional experiments, experimental animals received intraperitoneal injections of 8 ml of 12, 16, 20 and 25 percent solutions of mannitol, a non-metabolizable sugar-alcohol. Controls always received identical quantities of mammalian Ringer's solution administered via the same route as in the experimentals. Another set of 20 rats was used to determine glucose tolerance curves for each concentration of glucose and mannitol administered. No food intake depression occurred following intraperitoneal injections of 2, 5, 8 and 12 percent glucose, 12 percent mannitol and following intragastric loading of 25, 50 and 65 percent glucose. However, intraperitoneal injections of 16, 20 and 25 percent glucose and mannitol caused depression of food intake. No depression of food intake occurred following intragastric loading of 50 and 65 percent glucose solutions which raised blood glucose levels a minimum of 43 mg percent and 55 mg percent above basal, respectively, for the duration of the 3 hr feeding period. These minimum blood glucose levels greatly exceed normal values following a meal. It was concluded that blood glucose level per se is not an important feedback parameter in the long-term control of food intake, and the depression in food intake following intraperitoneal injections of 16, 20 and 25 percent glucose and mannitol solutions was due to an abnormal physiological condition.

Animals↗

Crohn disease lymph node homogenates produce murine lymphoma in athymic mice.

To study the putative agent(s) related to Crohn disease, we intraperitoneally in injected mesenteric lymph node homogenates from four patients with active Crohn disease into 10-week-old athymic (nu/nu) mice. Control mice (nu/nu) were injected with homogenates of mesenteric lymph nodes from two patients with ulcerative colitis and four patients undergoing elective cholecystectomy, and with a homogenate of a cervical lymph node containing sarcoid granuloma. Thirty-four mice received filtered or unfiltered homogenates from Crohn disease lymph nodes. Thirty-two mice received homogenates or filtrates from lymph nodes of control patients. Four mice from the group injected with Crohn disease homogenates from four different patients developed generalized lymphadenopathy due to lymphoma 10-28 weeks after th injection. Two additional mice developed lymphadenopathy due to plasma cell hyperplasia. None of the control mice developed lymphomas or lymphadenopathy. Two lymphomas were homogenized, filtered, and injected intraperitoneally into a second group of nu/nu mice, which also developed lymphoma within 8 weeks of injection. Two lymphomas were cultured in vitro and B cell sur?ACE MARKERS WERE IDENTIFIED. Indirect immunofluorescence studies in two lymphomas showed cytoplasmic staining of lymphoma cells with sera from 10 patients with active Crohn disease but not with sera from 13 control subjects, including 6 with ulcerative colitis and 7 with other gastrointestinal disorders. These results suggest that a transmissible factor present in Crohn disease lymph nodes produces lymphoma in nu/nu mice. Furthermore, sera of Crohn disease patients contain an antibody that recognizes an "antigen(s)" in the murine lymphoma.

Animals↗

Antineoplastic effect and toxicity of 1,25-dihydroxy-16-ene-23-yne-vitamin D3 in athymic mice with Y-79 human retinoblastoma tumors.

OBJECTIVES: To evaluate the in vivo efficacy and toxicity of the 1,25-dihydroxy-16-ene-23-yne-vitamin D3 (16,23-D3) analogue in athymic nude mice injected with Y-79 human retinoblastoma cells and to compare the efficacy and toxicity of this compound with those of 1,25-dihydroxycholecalciferol (D3, calcitriol). METHODS: Thirty athymic nude mice (4-6 weeks old) were injected subcutaneously with 1 x 10(7) Y-79 human retinoblastoma cells suspended in a 1:1 mixture of Iscove culture medium supplemented with 20% fetal bovine serum and basement membrane matrix suspension. Five days after tumor injection, the mice were randomized to 3 groups of 10 mice each. The first group served as a control group and received intraperitoneal injections of 0.25 mL of mineral oil (vehicle) 5 times a week. The second group received intraperitoneal injections of 0.05 microg of calcitriol in 0.25 mL of mineral oil intraperitoneally 5 times a week. The third group received intraperitoneal injections of 0.5 microg of 16,23-D3 in 0.25 mL of mineral oil 5 times a week. Injections were continued for 5 weeks, during which tumor size and mouse weight were individually measured. Toxicity was assessed by clinical measures such as lethargy, weight loss, and death. The mice were then killed and the size, volume, and weight of each tumor were determined. Also, in representative animals in each group, kidneys were evaluated for calcification and serum calcium concentration was measured. RESULTS: All experimental and control animals developed tumors subcutaneously. The 16,23-D3-treated mice had significantly smaller average tumor size (1.55 cm3) than the control mice (3.45 cm3) (P = .02), less gain in average body weight from the beginning of treatment (2.4 g vs 5.5 g) (P= .06), and a 40% mortality. The calcitriol-treated mice did not have significantly smaller average tumor size (1.26 cm3) than the 16,23-D3-treated mice (P = .35), had significant body weight loss compared with the control animals (calcitriol-treated mice lost 4.03 g) (P =.001), and had a mortality of 90% by the completion of the experiment. Histologically, there was no difference in the degree of tumor necrosis and calcification between control and experimental mice. Serum calcium concentrations were equivalent between the control (2.15 mmol/L [8.6 mg/dL]) and experimental groups (calcitriol, 1.88 mmol/L [7.5 mg/dL] [P = .97]; 16,23-D3, 2.15 mmol/L [8.6 mg/dL] [P = .42]). Mild bilateral renal tubular calcification occurred in 3 of 4 mice in the calcitriol-treated group and in 2 of 4 mice in the 16,23-D3-treated group. CONCLUSIONS: The growth of subcutaneous Y-79 human retinoblastoma cells in athymic nude mice is significantly reduced by treatment with intraperitoneal injections of 16,23-D3. The antineoplastic effect of calcitriol is not statistically significantly different but is associated with significantly more toxicity. 1,25-Dihydroxy-16-ene-23-yne-vitamin D3 may be a useful chemotherapeutic adjunct in the treatment of retinoblastoma.

Animals↗

Gabapentin markedly reduces acetic acid-induced visceral nociception.

BACKGROUND: Gabapentin has recently been used clinically as an antihyperalgesic agent to treat certain neuropathic pain states. The aim of this study is to test whether gabapentin is able to inhibit responses to peritoneal irritation-induced visceral pain and to examine the effect of gabapentin on spinal cord amino acid release. METHODS: The acetic acid-induced writhing assay was used in rats to determine the degree of antinociception. The rats received an intraperitoneal injection of acetic acid 40 min after intraperitoneal administration of vehicle or gabapentin (50, 100, or 200 mg/kg). Cerebrospinal fluid dialysate was collected by microdialysis from the spinal subarachnoid space in anesthetized rats. Acetic acid-induced release of amino acids into the dialysate, including glutamate, aspartate, serine, glutamine, and glycine, following intraperitoneal injection of acetic acid was evaluated by measurements of changes in the concentrations of these amino acids. The effects of pretreatment with saline or gabapentin (100 mg/kg intraperitoneal) on amino acid release were compared. RESULTS: Gabapentin reduced writhing responses in a dose-related fashion. Dialysate concentrations of glutamate, aspartate, and serine increased significantly following intraperitoneal injection of acetic acid, while glutamine and glycine concentrations were not increased significantly. When compared to saline-treated rats, animals pretreated with 100 mg/kg gabapentin showed suppression of the acetic acid-induced increases in glutamate, aspartate, and serine concentrations. CONCLUSIONS: These data demonstrate that gabapentin effectively inhibits acetic acid-induced nociception, and the antinociceptive effect of gabapentin correlates with the suppression of noxious-evoked release of excitatory amino acids in the spinal cord.

Acetates↗

[Effect of T suppressor cells on the maintenance phase of tolerance to cardiac allografts in the rats].

OBJECTIVE: To study the role of T suppressor cells in immune tolerance to cardiac allografts in the rats. METHODS: Male DA rat hearts were transplanted to male Lewis rats using Ono's model and randomly divided into five groups: group 1: untreated, group 2: portal venous injection of 3 x 10(8) DA splenocytes to Lewis rat, group 3: intraperitoneal injection of cyclophosphamide (80 mg/kg) to Lewis rat, group 4: portal venous injection of 3 x 10(8) DA splenocytes combined with intraperitoneal injection of cyclophosphamide (80 mg/kg) to Lewis rat, 15 days later heart transplantation was performed. Group 5: intravenous injection 3 (108 splenocytes of group 4 to normal recipient, and then heart transplantation was performed. Mean survival time (MST), histological changes, mixed lymphocyte reaction (MLR) were measured after operation. RESULTS: The survival time of heart allografts in the group 4 [MST: (71.5 +/- 29.1) d, t = -14.063, -13.915, -13.777; P < 0.01] was significantly longer than in the groups of 1 [MST: (7.3 +/- 1.0) d], 2 [MST: (7.8 +/- 0.8) d], 3 [MST: (8.2 +/- 1.1) d ]. Only a few inflammatory cells infiltrated in cardiac allografts in the groups of 4 and 5. MLR in the groups of 4 and 5 were significantly decreased compared with those of normal control (t = 29.902, 23.047; P < 0.01). CONCLUSIONS: Portal venous injection of donor splenocytes combined with intraperitoneal injection of cyclophosphamide could induce immune tolerance to cardiac allografts. The immune tolerance could be transferred through splenocytes. T suppressor cells play an important role in the immune tolerance.

Animals↗

Effect of parenterally injected benzimidazole compounds on Echinococcus multilocularis and Taenia crassiceps metacestodes in laboratory animals.

In mice infected with metacestodes of Taenia crassiceps, the following compounds were at least partially effective when injected intraperitoneally at the dosage indicated: cambendazole (500 mg/kg), mebendazole (6.25 mg/kg), oxibendazole (500 mg/kg), 5-benzamido-2(4-thiazolyl)benzimidazole (500 mg/kg), 2-carboethoxyamino benzimidazole (125 mg/kg), and 2-carbomethoxyamino benzimidazole (500 mg/kg). The following were inactive at the dosage indicated: parbendazole (500 mg/kg), thiabendazole (1,000 mg/kg), and fenbendazole (1,000 mg/kg). Mebendazole, which showed some activity at 6.25 mg/kg, was highly active as a single intraperitoneal dose at 25 mg/kg. When injected subcutaneously, mebendazole was much less active than when given intraperitoneally. In mice infected with metacestodes of Echinococcus multilocularis, intraperitoneal injection of mebendazole at 75 to 150 mg/kg, daily for 3 days, was highly effective (95 to 100% reduction in cyst mass). In contrast, oral administration at 1,000 mg/kg, daily for 3 days, was only partially effective. The drug was also effective when given intraperitoneally to infected cotton rats. A water-soluble benzimidazole, carboxymethyleneamino cambendazole, was approximately 50% effective in mice when injected daily for 3 days at a dosage of 75 or 150 mg/kg. The results suggest that, in metacestode infections of medical importance, it may be possible to kill the parasite by delivering a drug to its immediate vicinity, and so to reduce the required dosage with respect to the host.

Administration, Oral↗

Early effects of tribromoethanol, ketamine/xylazine, pentobarbitol, and isoflurane anesthesia on hepatic and lymphoid tissue in ICR mice.

We investigated the effects of various anesthetic agents on hepatic and splenic injury in mice. Three and six hours after intraperitoneal injection of TBE, intramuscular injection of ketamine/xylazine combination (K/X), intraperitoneal injection of pentobarbital (PB), and inhalation of isoflurane (IF), or intraperitoneal and intramuscular injection of control saline, mice were exsanguinated and serum was obtained for measurement of hepatic aspartate transaminase (AST), alanine transaminase (ALT) and gamma-glutamyltransferase (GGT). The spleen and liver also were obtained, and sections were examined by use of routine light microscopy for pathologic changes and for apoptosis, as determined by use of the in situ terminal deoxynucleotidyl transferase-mediated dUPT nick-end-labeling (TUNEL) histochemical analysis. Three hours after TBE or K/X administration, AST activity increased three- to fourfold above that in untreated and saline-injected control animals, and remained high at six hours. Administration of PB did not effect AST activity at three hours, but there was a significant increase at six hours. Activity of ALT was non-significantly increased three hours after TBE and K/X, but not PB administration. Administration of IF had no effect on hepatic enzyme activities, and GGT was not increased after administration of any of the agents. Markedly increased apoptosis was observed in splenic follicles and in hepatic Kupffer and endothelial cells at three hours after TBE and K/X administration, but apoptosis decreased to control levels by six hours. Increased apoptosis was not observed after IF administration. Administration of TBE and K/X causes injury to lymphocytes and to hepatic Kupffer and endothelial cells within three hours, and PB administration induces changes within six hours. Thus, use of these anesthetic agents should be avoided when experiments are being designed to test short-term effects of an experimental intervention on the spleen and possibly on all lymphoid tissues. In addition, they also should be avoided in experiments testing effects on hepatic tissue.

Alanine Transaminase↗

Aerosol and intraperitoneal administration of ribavirin and ribavirin triacetate: pharmacokinetics and protection of mice against intracerebral infection with influenza A/WSN virus.

Ribavirin is active in vitro but not in vivo against a number of viruses capable of causing encephalitis. Ribavirin triacetate (RTA), a lipophilic derivative, has been reported to be more effective than ribavirin in protecting animals from encephalitis. By using an influenza A/WSN virus encephalitis model, we demonstrated that RTA administered by small-particle aerosol was able to decrease the death rate and increase the time of survival. To determine if this beneficial effect was due to increased delivery of drug, the pharmacokinetic properties of ribavirin and RTA when administered as an aerosol or by intraperitoneal injection were examined. Aerosol administration of ribavirin or RTA gave significantly higher concentrations of ribavirin in the lungs and serum of mice than did intraperitoneal injection. There was no difference, however, in ribavirin levels when either ribavirin or RTA was administered by small-particle aerosol. In brain tissue, ribavirin concentrations increased with time and did not appear to decrease as rapidly as in lungs and serum. Mean peak ribavirin concentrations in the brain were higher following aerosol administration of ribavirin than RTA, and both were higher than that following intraperitoneal injection of either drug. Administration of ribavirin or RTA by intraperitoneal injection failed to protect mice from a lethal intracerebral inoculation of influenza A/WSN virus, while aerosolized RTA did protect mice. The pharmacokinetics of ribavirin in brain tissue following aerosol administration of either drug did not explain the advantage of RTA over ribavirin in protecting mice from intracerebral infection with influenza A/WSN virus.

Aerosols↗