Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0153470 (Spleen)
 4,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated possible mechanisms of the antitumor action of gamma-(9H-purine-6-yl) thiomethyl L-glutamate (6-MPG), a water-soluble derivative of 6-MP. In the double grafted tumor system, BALB/c mice were inoculated intradermally with 10(6) cells of MethA fibrosarcoma at the right inguinal region on day 0 (the primary tumor) and later with 3 x 10(6) cells at the left on day 10 (the secondary tumor). Intraperitoneal administration of 6-MPG at a dose of 100 mg/kg/day from day 3 through 7 completely prevented growth of the secondary tumor. 6-MPG showed no effect on growth of colon 26 adenocarcinoma cells inoculated in place of the secondary MethA cells (antigen specificity). 6-MPG did not inhibit the secondary MethA growth in the BALB/c (nu/nu) mouse. The inhibitory effect of 6-MPG on the secondary tumor growth was diminished by prior treatment of the primed animals with cyclosporin A and anti-Thy antibody. Spleen cells from the tumor-bearing mice treated with 6-MPG showed a tumor-neutralizing activity (Winn assay). Treatment of the spleen cells with anti-CD8 antibody plus complement diminished the tumor-neutralizing effect but that with anti-CD4 antibody plus complement did not, indicating that CD8-positive cells are responsible for potentiation of the tumor immunity. These results suggest that the antitumor effect of 6-MPG against the secondary tumor is elicited by augmenting tumor specific T-cell production.
 ...
PMID:Study on the mechanism of immunopotentiating antitumor effect of 6-MPG, a water-soluble derivative of 6-mercaptopurine. 928 48

Effects of the administration of gamma-(9H-purine-6-yl)thiomethyl L-glutamate (6-MPG), a water-soluble derivative of 6-mercaptopurine, on concomitant and sinecomitant immunity against the implanted MethA tumor were studied in BALB/c mice. In the concomitant immunity experiments, mice were intradermally inoculated with 1x10(5) MethA cells at the right inguinal region on day 0. In sinecomitant immunity experiments, mice were similarly inoculated on day -21, and the grown tumor was excised on day -11. Both the tumor-bearing and tumor-ectomized animals were re-inoculated with 3x10(6) MethA cells intradermally at the left inguinal region on day 10. Administration of 6-MPG (100 mg/kg, i.p.) on days 3 through 7 significantly inhibited growth of the re-inoculated tumor in both series of experiments. Cyclophosphamide, adriamycin, mitomycin C and cis-diamminedichloroplatinum (II) had no significant effect on the growth of the re-inoculated tumor in the tumor-ectomized mice. Spleen cells harvested from the 6-MPG-treated tumor-ectomized mice showed a strong tumor-neutralizing activity (Winn assay).
 ...
PMID:Augmentation of sinecomitant immunity in mice by gamma-(9H-purine-6-yl)thiomethyl L-glutamate (6-MPG), a water-soluble derivative of 6-mercaptopurine. 947 63

Natural killer (NK) cells are thought to play an important role in the control of metastatic dissemination. Therefore, stimulation of cytotoxic activity of NK cells against neoplastic cells could be preventive for metastatic spread. Bomirski amelanotic (Ab) melanoma of Syrian hamster is a transplantable tumor metastasizing preferably to the kidneys. During growth of the melanoma a significant depression of cytotoxic activity of NK cells of tumor hosts is observed. Treatment of melanoma-bearing hamsters with indomethacin provided in drinking water resulted in the increase of NK cytotoxic activity of blood cells and in the lower occurrence of kidney metastasis. Spleen cells obtained from healthy and melanoma-bearing hamsters were cultured in vitro with agents influencing NK activity. We found an augmentative effect of human interleukin 2 (IL2) and human tumor necrosis factor (TNF). We also observed the synergistic effect of IL2/TNF combination, which was present in both groups of animals. The stimulatory effects of cytokines could be potentiated by the additional supplementation of cultures with indomethacin. Similar experiments were performed on spleen cells isolated from the healthy and tumor-bearing animals treated in vivo with indomethacin. Also, in this group of hamsters in vitro stimulation of NK cell activity by the cytokines was effective. The studies presented may give insight into the pathogenesis of immune abnormalities seen in advanced stages of progression of Ab melanoma, and can provide an experimental basis for immunomodulation in this tumor model of spontaneous metastasis.
 ...
PMID:Indomethacin inhibits kidney metastasis in bomirski melanoma-bearing hamsters, and modulates natural killer cytotoxic activity of tumor hosts in vivo and in vitro. 985 38

Infection with Toxoplasma gondii in the acute phase results in nonspecific suppression of immunologic function in mice and humans. The present study examined the effects of a physical stressor, i.e., cold stress (CS), on macrophage function (nitrite production, parasite survival) and splenic blastogenesis in the acute phase of murine T. gondii infection. In our stress paradigm, female BALB/c mice were placed in cold water (1 +/- 0.5 C), 5 min each day for 8 days. Nitrite production and parasite survival were measured in cultured peritoneal macrophages obtained from mice subjected to CS after in vivo activation with interferon-gamma/lipopolysaccharide (CS + ACT), and in vitro infection with T. gondii tachyzoites. Peritoneal macrophages from CS + ACT mice showed decreased nitrite production compared to control but activated cells (ACT). Spleen cell proliferation to in vitro stimulation with the mitogens concanavalin A (Con A) and anti-CD3, and Toxoplasma lysate antigen (TLA) was measured in splenocytes obtained from BALB/c mice during the acute phase of infection with T. gondii. Mice subjected to CS and infection (CS + INF) had maximum splenocyte proliferation on days 8 and 15 followed by a subsequent decline on day 28 postinoculation (PI). In contrast, infected mice not subjected to stress (INF) showed decreased splenocyte proliferation on days 8 and 15 followed by an increase on day 28 PI. The rate of mortality was decreased in the CS + INF compared to the INF group during acute infection. These results suggest that CS may alter the pathogenesis of T. gondii infection by modulating acute-phase responses, provoking a state of transient disequilibrium between the host and parasite.
 ...
PMID:Cold stress-induced modulation of cell immunity during acute Toxoplasma gondii infection in mice. 1038 35

Phex is the gene whose mutation is the cause of X-linked hypophosphatemia in humans and mice. The organs expressing Phex in normal animals, and their possible sensitivity to stimulation by low phosphate diets, are unknown. In this study, Phex expression was measured in 6-wk-old normal B6C3H male and female mice and in 135 g Sprague-Dawley rats fed a normal phosphate diet or a low phosphate diet with deionized water ad libitum for 7 d. The animals were then anesthetized, and a variety of organs were collected and frozen in liquid nitrogen. Phex mRNA expression was measured in each organ by reverse transcription-polymerase chain reaction (RT-PCR) with primers specific for both Phex and glyceraldehyde-3-phosphate dehydrogenase (G3PDH). Southern blots were prepared, hybridized with 32P-labeled internal oligonucleotides, and quantified with a phosphor imager. The Phex/G3PDH ratio was computed, and the data were compiled as the mean +/- SEM. In these growing animals, the highest Phexexpression levels were found in the gonads, brain, and lung. In contrast, Phex expression in calvaria and femur was markedly less. Two significant changes were found in animals that were fed a low phosphate diet. Spleen showed a significant decrease in Phex mRNA levels on low phosphate diet (60+/-10% of normal P diet, n = 12/group, p = 0.002). The pituitary gland showed a significant increase in Phex expression with low phosphate diet (851+/-127% of G3PDH) over normal P diet (569+/-78%, n = 24 - 25/group, p = 0.03). No significant change was found in femur, calvaria, or a variety of soft tissues. In summary, Phex mRNA was found in most tissues examined. Expression levels varied by two orders of magnitude from highest to lowest with more in gonads, brain, and lung and with less in bone. Increased Phex mRNA was found in the pituitary gland of animals that were fed a low phosphate diet.
 ...
PMID:MRNA expression of Phex in mice and rats: the effect of low phosphate diet. 1105 Oct 50

The effects of an acidic polysaccharide isolated from the ethanol-insoluble and water-soluble fraction of Panax ginseng C. A. Meyer on immunomodulating activities were investigated. A high output nitric oxide synthase (iNOS) was shown in female BALB/c mice administered intraperitoneally with the acidic polysaccharide from ginseng. Newly synthesized iNOS protein was also observed in peritoneal macrophages cultured with interferon-gamma and the acidic polysaccharide. Spleen cells from acidic polysaccharide-treated mice did not proliferate in response to concanavalin A, but restored the responsiveness by the cotreatment of NG-monomethyl-L-arginine (NMMA) with concanavalin A. The treatment of mice with aminoguanidine, a specific iNOS inhibitor, alleviated the acidic polysaccharide-induced suppression of antibody response to sheep red blood cells. Present results suggest that the immunomodulating activities of the acidic polysaccharide were mediated by the production of nitric oxide.
 ...
PMID:Nitric oxide is involved in the immunomodulating activities of acidic polysaccharide from Panax ginseng. 1130 56

5-HT(1B) receptors have a regulatory role in serotonergic activity and influence feeding behavior and body weight. Because the absence of 5-HT(1B) receptors may cause changes in this regulation, body weight was measured in male and female 5-HT(1B) receptor knockout (5-HT(1B) KO) and wildtype (WT) mice from weaning until the age of 30 weeks. In both genders, 5-HT(1B) KO mice had a higher body weight than WT mice (17% and 9%, respectively). Body weight was significantly higher for males over the entire period and for females from Week 18 onwards. Absolute food and water consumption were related to body weight. However, relative to body weight, males consumed more than females. 5-HT(1B) KO males drank strikingly more water. Housing mice singly reduced food and water intake in males, but not in females. Plasma leptin levels and most organ weights did not differ between genotypes, indicating that higher body weight in 5-HT(1B) KO mice is not related to obesity. Relative to body weight, brains and adrenals were larger in females, while heart and liver were smaller. Kidneys were smaller in females, but larger in 5-HT(1B) KO mice, while lungs showed opposite effects. Spleen and testes were smaller in 5-HT(1B) KO mice. Although 5-HT(1B) KO males are more aggressive, testosterone levels were not different from WT mice. Basal corticosterone levels were similar in all groups and increased in response to mild stress, particularly in females. Lifelong absence of 5-HT(1B) receptors in mice resulted in clear phenotypic differences in body weights and food and water intake. Lacking this receptor increases body growth, without signs of obesity. A potential genetic background effect influencing this phenotype is discussed.
 ...
PMID:Male and female 5-HT(1B) receptor knockout mice have higher body weights than wildtypes. 1179 Apr 10

Ducklings were given egg-derived antibody against Salmonella enteritidis (Ab) in drinking water daily to determine if infection could be prevented. Pekin ducklings in all experimental groups were infected on Day 1 or 5 with 0.7 x 10(6) Salmonella enteritidis (SE). Spleen, liver, and intestine of each bird were collected and cultured on Days 7, 14, 21, and 28. Only livers and spleens were culture positive for SE. Ducklings infected on Day 1 had more SE infections than controls at each observation. Ducklings infected on Day 5 had fewer SE infections than controls on Days 7, 14, and 21. The same experiment was repeated to determine if SE infection could be prevented under production conditions. Only 10 ducks per group were infected with 1.02 x 10(7) SE. In addition to Ab, one group each, infected on Day 1 or 5, received a proprietary probiotic (Pro) daily to determine if Pro was synergistic to Ab. Groups receiving Ab and Pro and infected on Day 1 had fewer birds infected than Ab alone in Day 1-infected birds. Both Day 1-infected groups had more birds infected than controls. Birds infected on Day 5 had fewer ducks infected than controls on Days 7, 14, and 21. Except for Day 14, birds receiving both Ab and Pro and infected on Day 5 had fewer birds infected than Ab alone on Day 21 and 28. Probiotics act synergistically with oral Ab. Oral antibodies may serve as a tool to prevent salmonella infection in poultry.
 ...
PMID:Prevention of Salmonella enteritidis infection in commercial ducklings by oral chicken egg-derived antibody alone or in combination with probiotics. 1188 97

Methyl ethyl ketoxime is used primarily as an antiskinning agent in alkyd coating resins. Methyl ethyl ketoxime was selected for study because of the potential for human exposure and because of interest in oximes as a chemical class. Toxicity studies of methyl ethyl ketoxime (greater than 99% pure) were carried out in male and female F344/N rats and B6C3F1 mice. The compound was administered in drinking water for 14 days or 13 weeks. In addition, the genetic toxicity of methyl ethyl ketoxime was evaluated by determining mutagenicity in Salmonella typhimurium and induction of sister chromatid exchanges and chromosomal aberrations in cultured Chinese hamster ovary cells in vitro, with and without S9 activation. The frequency of micronucleated normochromatic erythrocytes in the peripheral blood of mice from the 13-week study was also determined. In the 14-day studies, groups of five male and five female rats and mice were given drinking water containing 0, 106, 312, 625, 1,250, or 2,500 ppm methyl ethyl ketoxime. The mean body weight gain of male rats in the 2,500 ppm group was significantly less than that of the controls; the final mean body weight of male mice in the 2,500 ppm group was also less than that of the controls. Spleen weights were increased in male and female rats in the 1,250 and 2,500 ppm groups. No chemical-related gross lesions were observed. Microscopic tissue evaluations were not performed. In the 13-week studies, groups of 10 male and 10 female rats were given drinking water containing 0, 312, 625, 1,250, 2,500, or 5,000 ppm and groups of 10 male and 10 female mice were given drinking water containing 0, 625, 1,250, 2,500, 5,000, or 10,000 ppm. Mean body weights and body weight gains of 2,500 and 5,000 ppm male rats and 10,000 ppm male and female mice were less than those of the controls; mean body weight gains of male rats in the 1,250, 2,500 and 5,000 ppm groups and females in the 2,500 and 5,000 ppm groups were also less than those of the controls. Hematology results of this drinking water study indicate that methyl ethyl ketoxime induces a methemoglobinemia and a responsive Heinz body anemia. Liver and spleen weights were generally significantly greater than those of the controls in male and female rats exposed to 1,250 ppm or greater; spleen weights were also increased in male and female mice in the 10,000 ppm groups. Kidney weights were significantly greater in male rats in the 5,000 ppm group and in female rats exposed to 1,250 ppm or greater than those of the controls. Microscopically, there were exposure-related increases in the incidences and severities of hematopoietic cell proliferation in the spleen at exposure concentrations of 625 ppm or greater in male and female rats and at 5,000 and 10,000 ppm in male and female mice. A significant increase in the incidence of hematopoietic proliferation in the bone marrow was observed in rats exposed to 625 ppm or greater. Liver Kupffer cell erythrophagocytosis and hemosiderin pigmentation, as well as renal tubule hemosiderin pigmentation, occurred in exposed rats and mice. Other lesions observed include hyperplasia of the transitional epithelial lining of the urinary bladder in male and female mice exposed to 2,500 ppm or greater and degeneration of the nasal olfactory epithelium in male and female rats in the 2,500 and 5,000 ppm groups, male mice in the 5,000 and 10,000 ppm groups, and female mice exposed to 2,500 ppm or greater. Methyl ethyl ketoxime is extensively metabolized and does not accumulate in tissues. Single gavage doses of 2.7, 27, or 270 mg/kg administered to rats were primarily converted to carbon dioxide, mostly in the first 24 hours after dosing. After intravenous administration, less radioactivity on a percentage basis was excreted as carbon dioxide than in the gavage study, and more of the administered dose was excreted in urine and as volatiles. Following dermal administration, significantly greater amounts of volatiles were excreted than after gavage or intravenous administration. The 270 mg/kg gavage dose may result in saturation of a metabolic pathway(s). There is some evidence that the ketoxime is metabolized to the ketone and, presumably, hydroxylamine. Methyl ethyl ketoxime was mutagenic in Salmonella typhimurium strain TA1535 when tested in the presence of hamster liver S9 activation enzymes; results of mutagenicity testing were negative in strains TA97, TA98, and TA100, with and without exogenous metabolic activation. No induction of sister chromatid exhanges or chromosomal aberrations was observed in cultured Chinese hamster ovary cells treated with methyl ethyl ketoxime, with or without S9, and no increase in the frequency of micronucleated erythrocytes was noted in peripheral blood obtained from male and female mice administered methyl ethyl ketoxime in drinking water for 13 weeks. In summary, the major target of methyl ethyl ketoxime is the erythrocyte; the no-effect level for erythrotoxicity is 625 ppm in male rats and 312 ppm in female rats based on erythrocyte counts after 13 weeks of exposure. The no-effect level for hematopoietic toxicity is 312 ppm in rats based on erythroid cell hyperplasia in bone marrow and 2,500 ppm in mice based on hematopoietic cell proliferation in the spleen. Hematology results of this drinking water study indicate that methyl ethyl ketoxime induces a methemoglobinemia and a responsive Heinz body anemia. Methyl ethyl ketoxime was at most weakly genotoxic; it induced mutations in S. typhimurium under very specific conditions and increased the frequency of sister chromatid exchanges in cultured Chinese hamster ovary cells, but it did not induce sister chromatid exchanges or chromosomal aberrations in cultured Chinese hamster ovary cells in vitro or increase the frequency of micronucleated erythrocytes in mice treated in vivo.
 ...
PMID:NTP Toxicity Studies of Methyl Ethyl Ketoxime Administered in Drinking Water to F344/N Rats and B6C3F1 Mice (CAS No. 96-29-7). 1198 78

Soil, water, and amphibian tissues collected between 1995 and 1999 from 15 study sites in Bermuda were analysed for pesticides and heavy metals. The most abundant pesticide residue in soil was p,p'-dichlorodiphenyldichloroethylene (DDE) which was found at all sites in concentrations ranging from 0.003 to 4.023 p.p.m. No pesticide residues were found in water. DDE was also recovered from the livers and fat bodies of marine toads (Bufo marinus) and whistling frogs (Eleutherodactylus johnstonei). Analyses of food sources consumed by these anuran species revealed residue levels of p, p'-DDE ranging from 0.05 to 0.217 p.p.m. Other soil residues included dichlorodiphenyltrichloroethane (DDT) at eight study sites, Dicofol(kelthane) at eight sites, dieldrin at five sites, and polychlorinated biphenyls (PCBs) as Arochlor 1254 and Arochlor 1260 at seven sites. Analyses of toad livers revealed significant concentrations of cadmium, chromium, copper and zinc. Livers of Bermuda toads exhibited altered hepatocytic morphology and an increased number of melanomacrophages and possible granulomas, while spleens showed a marked decrease in white pulp. Spleen cells from Bufo marinus collected at one site having high levels of cadmium exhibited a decreased B cell response to lipopolysaccharide. The incidence of trematode infection in Bufo marinus increased from 53.8% in 1995 to 90% in 1999. Deformity rates in the limbs of subadult and adult toads ranged between 15 and 25%. Examination of 1,995 newly-metamorphosed toads revealed deformity rates as high as 47%. The current comprehensive study suggests that environmental pollutants may account for immunosuppression, increased susceptibility to infections, limb malformations and possible decline in amphibian populations from Bermuda.
 ...
PMID:Role of environmental pollutants on immune functions, parasitic infections and limb malformations in marine toads and whistling frogs from Bermuda. 1274 35


<< Previous 1 2 3 4 5 6 7 8 9 Next >>