Feeding NOD mice with pig splenocytes induces transferable mechanisms that modulate cellular and humoral xenogeneic reactions against pig spleen or islet cells

We have reported previously that oral administration of pig cells to NOD mice modified xenogeneic cellular response against pig islet cells (PICs), and hypothesized that it may have induced active suppression. This preliminary report evaluated only the effect of feeding pig cells by 'primary' proliferation, i.e. when splenocytes from fed mice are confronted with pig cells in vitro. The present study also considered 'secondary' proliferation and cytokine production after feeding and subsequent in vivo graft of pig cells. Additionally, serum IgM and IgG isotypes were quantified by ELISA using pig target cells. Induction of active mechanism by feeding was hypothetical, which led us here to transfer splenocytes from mice fed pig spleen cells (PSC) and evaluate 'primary' (after transfer) and 'secondary' (after transfer and subsequent graft of pig cells) proliferations and cytokine secretions in recipient mice. We also determined whether the effects of feeding pig cells persisted after depression of suppressor mechanisms by cyclophosphamide. Mice fed with PSC displayed increased 'primary' splenocyte proliferation to PSC or PIC (P < 0.0001), while 'secondary' responses were decreased (P < 0.03) in those fed PSC and subsequently grafted with PSC. The increased 'primary' and decreased 'secondary' proliferations were reduced (P < 0.04) by pretreatment with cyclophosphamide. The IL-10/ and IL-4/IFNgamma ratios produced in response to PSC increased (P < 0.04) in mice fed and grafted with PSC compared to those grafted only with PSC. IgM and IgG levels against pig cells were, respectively, increased (P < 0.04) and decreased (P < 0.04) in mice fed and grafted with PSC. IgG2a and IgG2b, but not IgG1, levels were lower (P < 0.01). These effects of feeding PSC on 'secondary' proliferation, cytokine and antibody productions, were not detected when mice were fed PSC only after graft with PSC. Transfer with splenocytes from mice fed PSC increased 'primary' proliferation of splenocytes from recipient mice in response to PSC (P < 0.02) or PIC (P < 0.05). After transfer with splenocytes from PSC-fed mice and graft with PSC, 'secondary' proliferation to pig cells were reduced (P < 0.04), and the IL-10/IFNgamma ratio produced in response to PSC was increased fourfold. Thus, oral administration of PSC induces active transferable mechanisms, characterized by a biphasic pattern with early increased 'primary' xenogeneic cellular reactions to both PSC and PIC, followed by decreased 'secondary' responsiveness and a concomitant shift of the Th1/Th2 balance towards greater Th2 influence. Decreased responsiveness may be due to active suppression, even though induction of anergy or deletion cannot be excluded.     

Inhibitory effect of oral administration of Lactobacillus casei on 3-methylcholanthrene-induced carcinogenesis in mice

The present study was designed to determine whether tumor induction by 3-methylcholanthrene (MC), a carcinogenic hydrocarbon, can be inhibited by oral administration of Lactobacillus casei strain Shirota (LC). C3H/HeN mice were divided into four groups and assigned to the following treatments: treated with MC and given control or LC-containing diet; treated with vehicle only and given control or LC-containing diet. MC (1 mg) was injected intradermally at 7 weeks of age and the tumor incidence was monitored; LC was mixed into a diet at a concentration of 0.05% (w/w) and the diet was fed from the day of MC injection throughout the study. Spleen cells were analyzed for the immune parameters at 12 and 16 weeks after the MC injection. Oral feeding of mice with LC reduced tumor incidence (P < 0.05). MC treatment lowered the in vitro response to concanavalin A (Con A) of spleen cells, the secretion of interleukin-2 in spleen cell culture after stimulation of the cells with Con A and the proportions of CD3⁺, CD4⁺ and CD8⁺ splenic cells. However, the analysis of the spleen cells obtained from the mice treated with MC and given the LC-containing diet revealed that these disrupted host immune parameters were maintained at the level of normal controls. These results suggest that oral feeding of mice with LC inhibits MC-induced tumorigenesis by modulating the disrupted host immune responses during MC carcinogenesis. Received: 14 April 1999     

Acute effects of vitamin B6 and fixed combinations of vitamin B1, B6, B12 on nociceptive activity evoked in the rat thalamus: Dose-response relationship and combinations with morphine and paracetamol

Summary Nociceptive activity was elicited in neurones of the thalamus by supramaximal electrical stimulation of afferent C fibres in the sural nerve of rats under urethane anesthesia. The fixed combination of vitamin B₁, B₆, B₁₂ (Neurobion^®) as well as of vitamin B₆ administered by i.p. injection dose-dependently reduced the evoked nociceptive activity. The ED₅₀ of Neurobion^® is 4.6 ml/kg (at 100 min after injection) and that of vitamin B₆ is 189mg/kg (at 90 min after injection). The minimum effective doses of Neurobion^® and vitamin B₆ are 0.5 ml/kg and 40 mg/kg, respectively. When Neurobion^® or vitamin B₆ were given at their minimum effective doses, and the minimum effective doses of morphine (0.025 mg/kg) or paracetamol (5 mg/kg) were injected i.v. 80 min later, i.e., when the maximum effect of higher doses of Neurobion^® or vitamin B₆was about to develop, no supraadditive effect developed. It is concluded that the antinociceptive effect caused by a single injection of Neurobion^® is largely due to vitamin B₆. Vitamin B₁₂ may contribute to this effect, whereas vitamin B₁ alone exhibited only a slight effect on nociception. Moreover, it appears that Neurobion^® produces its antinociceptive effect after a single injection and after repeated administration during several days by different mechanisms so that the effect of analgesic agents is not enhanced following a single injection of Neurobion^® but may be enhanced after repeated administration of the compound.     

Controlled administration of penicillin to patients with a positive history but negative skin and specific serum IgE tests

BACKGROUND: Although subjects with a positive history of immediate allergy to penicillin and negative skin test are traditionally considered to tolerate penicillin, current evidence indicates that they may develop an immediate reaction despite negative skin and serum specific IgE tests. It is thought that these patients require additional tests to confirm the diagnosis. OBJECTIVE: To assess in a large group of patients with a history of immediate allergy to penicillins but with both skin test and CAP-FEIA-negative to classical and side chain penicillin determinants, the role of controlled administration of betalactams as a diagnostic test. METHODS: A group of 330 patients with a history of immediate allergic reactions to penicillins was studied by two evaluators from the same allergy unit using the following protocol: skin tests with major and minor determinants of benzylpenicillin (benzylpenicilloyl-poly l-lysine and minor determinant mixture), amoxicillin and ampicillin, and determination of specific IgE antibodies to penicillins, by CAP-FEIA, in serum. If both tests proved negative, a controlled administration of the drug was then carried out. RESULTS: A total of 89 (27%) patients were skin test and CAP-FEIA-negative and therefore required controlled administration of the drug. Of these, 49 developed an immediate response and were therefore considered allergic, and the remainder had good tolerance after administration of both benzylpenicillin and amoxicillin. The clinical characteristics of this group were similar to the other allergic patients who were skin test or CAP-FEIA-positive, except that they were younger (P < 0.01). Twenty-two (45%) developed a response to benzylpenicillin and 27 (55%) had a selective response to amoxicillin. Although all reactions appeared within 1 h, a positive correlation was found between the dose inducing the response and the time elapsed from drug administration, for both benzylpenicillin and amoxicillin (P < 0.001). CONCLUSION: These data indicate that an important number of subjects are not correctly identified if only skin tests and/or CAP-FEIA are used and that this is particularly relevant for side chain-specific reactions and younger subjects. This suggests that new diagnostic tests are required so as to limit the use of controlled administration.     

Oral administration of muscle derived small molecules inhibits tumor spread while promoting normal cell growth in mice

Tumor metastases are extremely rare in striated muscles. This is surprising given the fact that this tissue constitutes 60% of body weight. The present study focuses on small molecules produced and secreted by muscle cells which possess anti-cancer activity in vivo. Recently we have shown that a low molecular weight fraction (<1000 Dalton) of skeletal muscle cell conditioned medium (muscle factor-MF), markedly inhibits the proliferation of carcinoma, sarcoma or melanoma cell lines in vitro. The MF exerts a cytostatic effect on tumor cell growth and arrests the cells in the G0/G1 of the cell cycle. However, normal cell proliferation, such as bone marrow and fibroblasts, was stimulated following incubation with MF. In this study, the effect of orally administered MF on melanoma and sarcoma growth was examined in mice. The administration of MF to mice inoculated intravenously with melanoma (B16–F10) or sarcoma (MCA-105) cells, resulted in a statistically significant inhibition of metastatic lung foci. In a different model, melanoma was induced in the foot pad and after development of a local lesion, the leg was amputated. A prolonged survival time was observed in the MF treated groups. Since the MF stimulated bone marrow cell proliferation in vitro, we decided to test its efficacy as an inhibitor of the myelotoxic effect exerted by chemotherapy, in vivo. MF, administered after chemotherapy, restored the number of white blood cells and yielded an increased percentage of neutrophils compared with the decline in these parameters after administration of chemotherapy alone. Thus, it is indicated that MF exerted a systemic anti tumor and chemoprotective effect when given orally. It can be concluded that it is bioavailable and is not biodegradable in the digestive system. MF may be considered as a potential therapy for the prevention of tumor spread. This revised version was published online in July 2006 with corrections to the Cover Date.     

An improved technique for repeated gavage administration to rat neonates

ABSTRACT  The technique for gavage administration to rat nurslings was improved to allow determination of the direct effects of chemical substances in the nurslings. Rat neonates were treated with distilled water from postnatal day 1 through 20 using this technique. The viability of neonates during the administration period was comparable to that of untreated neonates. No adverse effects of this technique on the development of neonates were found, and no histological alterations of the esophagus or pharynx. Therefore, we conclude that use of our improved gavage administration method will contribute to ensuring successful neonatal development and thus allowing accurate assessment of the toxicological effects of test compounds on rat nurslings.     

实体肿瘤药物输运与给药方式的集中参数模型及实验研究

目的研究不同给药方式对实体肿瘤抗癌药物疗效的影响,并通过动物实验验证。方法分别建立体内药代动力学和肿瘤内药物输运的集中参数模型,模拟单次快速注射和等时间间隔三次快速注射时肿瘤间质组织药物浓度Ct随时间的变化。实验小鼠分为两组,分别进行抗癌药羟基喜树碱(HCPT)单次快速注射和等时间间隔3次快速注射,观察其肿瘤内药物平均浓度。对数值模拟结果和动物实验结果进行比较。结果数值模拟结果显示,对于相同总量药物,等量等间隔的三次给药,肿瘤间质组织药物浓度Ct高于单次给药。动物实验的实测结果相同。结论3次给药的效果显著优于单次给药。集中参数模型基本能够定量反映不同给药方式的效果。     

Intermediate-term toxicity of repeated orally administered doses of the anti-malarial β-artemether in dogs

The artemisinin derivative beta-artemether, an anti-malarial, was evaluated for its toxicity and tolerability in a 2-week, multiple-dose study in dogs. Eight beagle dogs (4 females, 4 males) were given beta-artemether by oral gavage 3 times daily at 45 mg/kg/dosing (a total daily dose-level of 135 mg/kg) for 2 weeks. This beta-artemether dose regime was well tolerated. Body weight changes were normal although feed consumption during the treatment period reduced compared to that of the pre-trial period. Clinical signs were transient spells of soft to liquid feces. On completion of the treatment period, the animals were sacrificed and submitted to a full macroscopic post-mortem examination. Designated organs were weighed and a complete light microscopic examination was performed on 43 selected tissues from 1 animal per sex, and on the liver, kidneys, thymus, mandibular lymph nodes and lungs of the three other animals per sex. Major findings were high liver weight and histopathologic findings of slight diffuse hepatocellular hypertrophy and distal tubular dilatation, together with flattened epithelium, in the kidneys. With the dose regime used in this trial beta-artemether produced no clinical or apparent histopathological signs of neurotoxicity in dogs.     

Effect of rectal administration of rebamipide on dextran sulfate sodium-induced colitis: Role of hepatocyte growth factor

Objective and design: Since rebamipide is effective for the treatment of ulcerative colitis (UC), we examined the involvement of hepatocyte growth factor (HGF) in the action of rebamipide. Materials: Fifty-five and forty female Balb/c mice, respectively, were used in Exp. 1 and 2. Treatment: 50 mg/kg/day rebamipide (Exp. 1) and 1 × 10⁷ pfu pAxCAHGF (the CAG promoter-driving HGF gene in adenovirus vector) (Exp. 2) were intrarectally introduced after induction of colitis by 4 % dextran sulfate sodium (DSS). Methods: Therapeutic effects were assessed by cell proliferation and apoptosis. Results: Rebamipide caused proliferation of epithelial cells at 10 days after treatment, and decreased apoptosis at 10, 14 and 21 days, compared with controls. Expression of HGF was greatly increased in rebamipide-treated mice. pAxCAHGF caused cell proliferation and apoptosis, which showed the same pattern as with rebamipide treatment. Conclusions: Rectal administration of rebamipide is effective for DSS-induced colitis in association with induction of HGF. Received 17 June 2006; returned for revision 23 August 2006; returned for final revision 29 October 2006; accepted by I. Ahnfelt-R?nne 14 December 2006