Heavy metal modulation of lymphocyte activities. 1. In vitro effects of heavy metals on primary humoral immune responses

The ability of heavy metals to modulate in vitro primary humoral immune responses has been investigated. The relative immunosuppresive activities of the heavy metals tested were Hg²⁺ > Cu²⁺ > Mn²⁺ > Co²⁺; Cd²⁺ > Cr³⁺; Sn²⁺; Zn²⁺. Fe²⁺ had no significant effect on the development of SRBC-specific plaque-forming cells (PFC), and Pb²⁺ and Ni²⁺ enhanced the PFC response. The immunosuppressive activities of the heavy metals usually correlated with their toxicity and their inhibition of lymphocyte proliferation. The immunopotentiating metals, Pb²⁺ and Ni²⁺, alone induced lymphocyte proliferation, and they increased the proliferative response induced by LPS and 2-ME but not Con A and PHA. Although Pb²⁺ and Ni²⁺ were the only two heavy metals tested which enhanced lymphocyte reactivity, they did not appear to function via similar mechanisms. Pb²⁺ appeared to enhance the development of PFC by directly interacting with lymphocytes and altering their activity since lymphocyte preincubation with Pb²⁺ was sufficient for enhancement; whereas, lymphocyte preincubations with Ni²⁺ did not induce enhancement. Pb²⁺ did not appear to alter the immunogenicity of the antigens employed; however, pretreatment of SRBC with Ni²⁺ eliminated their ability to stimulate a SRBC-specific response in vitro. Inhibition of the PFC response by the chelator EGTA could be reversed by Ca²⁺ or Ni²⁺, but not by Cu²⁺, Hg²⁺, Pb²⁺, or Zn²⁺. The stimulatory activity of Pb²⁺ and Ni²⁺ could not be accounted for by significant alteration of the antigenicity of the lymphocytes, because heavy metal preincubated syngeneic cells were not stimulatory for untreated syngeneic cells. On the other hand, Pb²⁺ and Ni²⁺ did slightly enhance the mixed lymphocyte culture (MLC) response to allogeneic cells; Hg²⁺ inhibited the MLC response.     

An assessment of the ability of phthalates to influence immune and allergic responses

It has been suggested that one possible contributor to the increasing prevalence of atopic (IgE-mediated) allergic diseases and asthma in Europe and the US is exposure to chemicals that may act as adjuvants. Certain commonly used phthalate plasticisers, such as di-(2-ethylhexyl) phthalate, have been implicated in this regard. The evidence for the ability of phthalates to impact on immune and allergic responses has been examined, encompassing epidemiological investigations and results deriving from studies using experimental animals and from analyses in vitro. The epidemiological data provide some evidence that exposure to phthalates may be associated with increased risk of development of allergies and asthma, however, the lack of objective exposure information limits the interpretation. A variety of studies have been performed in mice to examine the influence of phthalate (delivered via various routes of exposure) to impact on immune responses. Measurement of antibody responses is the commonest read out, although other parameters of inflammation such as eosinophil infiltration and cytokine production have been used also. Although certain phthalates, when delivered at appropriate doses, and via an appropriate route, have been reported to impact on immune and inflammatory function in rodents, as yet no consistent pattern has emerged. Results ranged from potentiation of immune or inflammatory responses, to the absence of any effect, to inhibitory or immunosuppressive activity. In addition, comparatively low doses of phthalates have been associated with immune effects only when routes of administration (subcutaneous or intraperitoneal) are used that do not reflect, and are much less relevant for, opportunities for human contact with phthalates. There is clearly a case to be made for the design of more definitive animal studies that will allow development of a more detailed understanding of whether and to what extent, and under what conditions, phthalates are able to effect meaningful changes in immune function that may in turn impact on human health.     

Evidence that naloxone attenuates the consumption of food by domestic pigeons through a central influence

Three experiments were performed on domestic pigeons deprived of food for 24 hr to determine whether the anorexic influence of naloxone, which is observed in this species, results from a central effect of this drug. Injections were given 15 min before the delivery of food, and repeated measures of the consumption of food were obtained during the next 20 min. The systemic administration of either 2 or 10 mumol of naloxone, but not of equimolar amounts of quaternary naloxone, that does not traverse the blood-brain barrier, reduced the consumption of food of the pigeons. At a dose of 20 mumol, quaternary naloxone also slightly attenuated the ingestion of food, possibly because this drug can penetrate the blood-brain barrier when given in large doses. In another experiment, the intraventricular administration of 12.5, 25, 50, or 100 micrograms of naloxone attenuated the food intake in a dose-related fashion. Injection of 25 micrograms of the antagonist was more efficient in this respect when administered intraventricularly rather than systemically. From these experiments, it is concluded that in pigeons, the anorexic influence of naloxone is, at least partly, centrally mediated.     

Modifications in food intake and energy metabolism in rats as a function of chronic naltrexone infusions

The effects of chronic naltrexone infusions on food intake and energy balance were examined in male rats. Animals were fed either Purina Chow, or chow plus a 32% sucrose solution. After one week of being maintained on these diets, animals were implanted (intrascapularly) with osmotic minipumps infussing either 200 μg/kg/hr naltrexone hydrochloride or saline. Sucrose + chow-fed animals exhibited increased O₂ consumption, increased CO₂ roduction and an elavation in the respiratory quotient (RQ) relative to chow-fed controls. When infused with naltrexone, sucrose + chow-fed animals decreased food intake and body weight gain. While chow-fed animals also suppressed food intake and body weight gain, these decreases were not as great as those observed in sucrose + chow-fed animals. As a function of naltrexone administration, both chow-fed and sucrose + chow-fed animals altered their metabolism as reflected by decreased RQ and adiposity as determined by skinfold measurements. In addition, sucrose feeding led to a hyperthermia which was reversed by naltrexone infusions. Thus, chronic naltrexone administration depressed appetite, reduced energy production and induced hypothermia in rats. As naltrexone is thought to block the endogenous opioid system, this suggests that the endorphins are involved in the regulation of food intake and thermogenesis.     

The effect of the food matrix on in vivo immune responses to purified peanut allergens.

There is little knowledge about the factors that determine the allergenicity of food proteins. One aspect that remains to be elucidated is the effect of the food matrix on immune responses to food proteins. To study the intrinsic immunogenicity of allergens and the influence of the food matrix, purified peanut allergens (Ara h 1, Ara h 2, Ara h 3, or Ara h 6) and a whole peanut extract (PE) were tested in the popliteal lymph node assay (PLNA) and in an oral model of peanut hypersensitivity. In the PLNA, peanut proteins were injected into the hind footpad of BALB/c mice; in the oral exposure experiments C3H/HeOuJ mice were gavaged weekly with PE or allergens in the presence of cholera toxin (CT). Upon footpad injection, none of the allergens induced significant immune activation. In contrast, PE induced an increase in cell number, cytokine production, and activation of antigen-presenting cells. Furthermore, the presence of a food matrix enhanced the immune response to the individual allergens. Oral exposure to the purified allergens in the presence of CT induced specific IgE responses, irrespective of the presence of a food matrix. These results suggest that purified peanut allergens possess little intrinsic immune-stimulating capacity in contrast to a whole PE. Moreover, the data indicate that the food matrix can influence responses to individual proteins and, therefore, the food matrix must be taken into account when developing models for allergenic potential assessment.     

Feeding responses to a high dose of 8-OH-DPAT in young and adult rats: influence of food texture

The present study was undertaken to investigate the hyperphagic responses to the 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), in young and adult rats fed either a powder diet or pellets. In the young rats, 8-OH-DPAT (500 micrograms/kg s.c.) increased the consumption of pellets--but not powder--during the 2 h following drug administration. On the other hand, 8-OH-DPAT did not promote hyperphagia in adult rats presented with either pellets or a powdered diet. The influence of the 5-HT1A agonist on midbrain serotonin (5-hydroxytryptamine, 5-HT) turnover was examined. Administration of 8-OH-DPAT (500 micrograms/kg s.c.) induced similar decreases in 5-HT turnover, as reflected by the ratio of 5-hydroxyindoleacetic acid (5-HIAA) to 5-HT, in young and adult rats 1 h after administration. Nevertheless, some metabolic responses to 8-OH-DPAT were found to be influenced by age. Young and adult rats were injected with a low dose of 8-OH-DPAT (50 micrograms/kg s.c.) to specifically test the presynaptic regulation of 5-HT turnover. Again, midbrain 5-HIAA to 5-HT ratios were decreased to the same extent in both young and adult rats. The results suggest that (i) gnawing may be an important parameter in the food consumption that is triggered by a high dose of 8-OH-DPAT, (ii) analysis of the presynaptic effects of 8-OH-DPAT on 5-HT turnover cannot solely explain the influence of the agonist on feeding behavior.     

食物过敏患儿规范化饮食干预后临床症状和免疫状态的变化

目的 探讨规范化饮食干预改善食物过敏(FA)患儿临床症状和免疫状态的效果.方法 将60例FA患儿随机均分为观察组和对照组.观察组采取规范化饮食干预,包括规避进食引发FA的食物、使用配方奶替代喂养、筛查和评估患儿的营养状况和适时指导监护人的喂养行为;对照组给予常规饮食.记录饮食干预后2、6、9个月时CD3+CD4+/CD...     

The influence of opioids on the humoral and cell-mediated immune responses in mice. The role of macrophages

BackgroundOur experiments were aimed to test the influence of treatment with different opioids (morphine, fentanyl, methadone) on the humoral and cell-mediated immune responses.MethodsMice were treated intraperitoneally (ip) with opioids for several days and next either immunized with sheep red blood cells (SRBC) to test the antibody production or skin-sensitized with hapten picryl chloride (PCL) to induce contact hypersensitivity (CHS). In addition, the effects of opioids on the production of reactive oxygen intermediates (ROIs) and cytokines by peritoneal macrophages (Mf) and on the expression of surface markers on these cells and blood leukocytes were estimated.ResultsOpioids caused an enhancement of ROIs and cytokines production when macrophages were stimulated with zymosan or lipopolysaccharide (LPS) and reduced the expression of antigen presentation markers on Mf. Numbers of anti-SRBC plaque forming cells (PFC) and antibodies titres were lower in mice treated with all tested opioids. Depending on the use of particular opioid and the phase of allergic reaction, effects of the treatment on CHS were diverse. While morphine decreased the early and late phases of induction of CHS responses, methadone increased both reactions. In case of the effector phase of CHS, morphine and fentanyl increased both its early and late stages, while methadone decreased the late reaction. Treatment of recipients with opioids had diverse influence on the passive transfer of CHS in these animals.ConclusionsOur experiments show that the action of opioids on the immune system is a complex phenomenon dependent on such variables as type of opioid, character of response (humoral versus cellular) and types of cells involved. Here Mf seem to play a significant role.     

间歇低氧-肺气肿大鼠的炎症及免疫反应特点研究

摘要:目的 建立间歇低氧(IH)-肺气肿大鼠模型, 探讨其引起炎症和免疫反应的特点。方法 60 只 Wistar 大鼠随机分成对照组、 肺气肿组、 IH 组和重叠组(肺气肿合并 IH 组)。每组 15 只。造模成功后使用流式细胞仪测定各组外周血中性粒细胞 （PMN）、 CD3+ CD8+ T 细胞、 CD3+ CD4+ T 细胞凋亡率水平。酶联免疫吸附试验 （ELISA） 法测定血浆中肿瘤坏死因子(TNF)-α、 白细胞介素 （IL） -6 水平。取大鼠肺泡灌洗液(BALF), 在光镜下计算巨噬细胞、 外周血 PMN 和淋巴细胞比例。采集肺、 肝脏、 胰腺组织和右颈动脉并进行病理评分。结果 重叠组中 PMN、 CD3+ CD8+ T 细胞凋亡率与其他 3 组相比较低, CD3+ CD4+ T 细胞凋亡率、 TNF-α、 IL-6 表达水平最高 （均 P < 0.05）。BALF 中, 肺气肿组巨噬细胞和 PMN 百分比高于其余 3 组 （均 P < 0.05）。重叠组中肺、 肝脏、 胰腺、 右颈动脉内中膜厚度的病理评分高于其他 3组 （均 P < 0.05）。结论 肺气肿合并IH 可产生更严重的系统性多器官炎症和免疫反应。     

Critical role of the endocannabinoid system in the regulation of food intake and energy metabolism, with phylogenetic, developmental, and pathophysiological implications

The endocannabinoid system (ECS) consists of two receptors (CB(1) and CB(2)), several endogenous ligands (primarily anandamide and 2-AG), and over a dozen ligand-metabolizing enzymes. The ECS has deep phylogenetic roots and regulates many aspects of embryological development and homeostasis, including neuroprotection and neural plasticity, immunity and inflammation, apoptosis and carcinogenesis, pain and emotional memory, and the focus of this review: hunger, feeding, and metabolism. The ECS controls energy balance and lipid metabolism centrally (in the hypothalamus and mesolimbic pathways) and peripherally (in adipocytes and pancreatic islet cells), acting through numerous anorexigenic and orexigenic pathways (e.g., ghrelin, leptin, orexin, adiponectin, endogenous opioids, and corticotropin-releasing hormone). Obesity leads to excessive endocannabinoid production by adipocytes, which drives CB(1) in a feed-forward dysfunction. Phylogenetic research suggests the genes for endocannabinoid enzymes, especially DAGLalpha and NAPE-PLD, may harbor mildly deleterious alleles that express disease-related phenotypes. Several CB(1) inverse agonists have been developed for the treatment of obesity, including rimonabant, taranabant, and surinabant. These drugs are efficacious at reducing food intake as well as abdominal adiposity and cardiometabolic risk factors. However, given the myriad beneficial roles of the ECS, it should be no surprise that systemic CB(1) blockade induces various adverse effects. Alternatives to systemic blockade include CB(1) partial agonists, pleiotropic drugs, peripherally restricted antagonists, allosteric antagonists, and endocannabinoid ligand modulation. The ECS offers several discrete targets for the management of obesity and its associated cardiometabolic sequelae.     

The influence of food on the bioavailability of a slow release theophylline preparation

Food-induced changes in the absorption of Theostat 300, a controlled release formulation of theophylline, have been studied in healthy volunteers. This open, randomised, 3-way, single-dose study involved 12 volunteers who received the drug either while fasting, or with a standardised low-fat (10g), or high-fat (60g) breakfast. Each subject was studied over a 3-week period, with 3 separate days of oral treatment and a 7-day washout period between treatments. The results showed no differences in AUC0-24 and tmax values between the 3 kinds of diet. The only differences observed concerned absorption. Food intake increased Cmax values by 20%. The steady-state peak concentration obtained by means of simulated plasma levels was not influenced by food intake. This slight food-drug interaction of Theostat 300 seemed to be of no clinical significance.     

The release and induced immune responses of a plant-made and delivered antigen in the mouse gut

This study investigated the site of release of a model vaccine antigen from plant cells and the corresponding induced immune response. Three plant tissues (leaf, fruit and hairy root) and two formulations (aqueous and lipid) were compared in two mouse trials. A developed technique that enabled detection of antigen release by plant cells determined that antigen release occurred at early sites of the gastrointestinal tract when delivered in leaf material and at later sites when delivered in hairy roots. Lipid formulations delayed antigen release from all plant materials tested. While encapsulation in the plant cell provided some protection of the antigen in the gastrointestinal tract and influenced antigen release, formulation medium was also an important consideration with regard to vaccine delivery and immunogenicity. Systemic immune responses induced from the orally delivered vaccine benefited from late release of antigen in the mouse gastrointestinal tract. The influences to the mucosal immune response induced by these vaccines were too complex to be determined by studies performed here with no clear trend regarding plant tissue site of release or formulation medium. Expression and delivery of the model antigen in plant material prepared in an aqueous formulation provided the optimal systemic and mucosal, antigen-specific immune responses.     

A nano silicon adjuvant enhances inactivated transmissible gastroenteritis vaccine through activation the Toll-like receptors and promotes humoral and cellular immune responses

Inactivated transmissible gastroenteritis virus (TGEV) vaccines are widely used in swine herds in China. These are limited, however, by the need to elicit both humoral and cellular immunity, as well as the efficiency of adjuvants. In this study, a 70-nm nano silicon particle was applied with inactivated TGEV vaccine in mice, and its immune-enhancing effects and mechanism of action investigated. We found that nano silicon applied with inactivated TGEV vaccine induced high antibody titers, increase IL-6, TNF-α and IFN-γ expression, and stimulate CD3+ T cell proliferation with a high CD4+/CD8+ T lymphocyte ratio. Nano silicon could quickly activate innate and adaptive immunity by stimulating Toll-like receptor signaling pathways, indicating that the nano silicon adjuvant enhanced long-term humoral and early cellular immune responses when combined with inactivated TGEV vaccine. Nano silicon could be considered for use as an antigen- carrier and adjuvant for veterinary vaccines.     

Effect of a bacterial extract on cellular and humoral immune responses in humans

A lyophilized extract from E. coli (OM-89) was studied for its immunomodulating properties and tolerance in humans. Its oral administration to healthy volunteers produced a selective increase in the active T-cell population without changes in other lymphocyte populations. A significant increase in the proliferative response to concanavalin A and phytohemagglutin was recorded, but not to pokeweed mitogen. No significant changes were observed in the serum levels of IgG, IgA and IgM. The clinical and biological tolerance of OM-89 was excellent, without any adverse side-effects or production of circulating immune complexes or of autoantibodies, while the in vitro investigation showed that it is not a mitogen. Thus in healthy subjects OM-89 seems to act mainly on the cell-mediated immune responses.     

The influence of food on the bioavailability of a twice-daily controlled release carbamazepine formulation

Carbatrol, a new dosage form of carbamazepine (CBZ), was developed consisting of three different types of pellets (immediate release, controlled release, and enteric release). The objective of this study was to explore the influence of food on absorption of CBZ. This was a randomized, open-label, single-dose crossover study conducted in 12 healthy volunteers. Treatments were 2 x 200 mg Carbatrol with a high-fat meal, fasted, or sprinkled over applesauce (but otherwise fasted). Each subject received one dose of each treatment separated by a washout period of at least 2 weeks. CBZ bioequivalence was established based on the equivalence of AUC (extent of absorption) in all three conditions. Carbatrol may be taken with or without food or the capsule opened and sprinkled on food.     

Heavy metals in vegetables collected from production and market sites of a tropical urban area of India

Vegetables (Beta vulgaris L., Abelmoschus esculentus L. and Brassica oleracea L.) from the production and market sites of India were tested for Cu, Cd, Zn and Pb. At market sites, the mean concentration of Cu in cauliflower, and of Zn and Cd in both palak and cauliflower had exceeded the PFA standard. Zn at the production sites also exceeded the PFA standard in cauliflower. Cd concentration in vegetables tested from both production and market sites was many folds higher than the EU standard. In contrast, Pb in vegetables tested from both production and market sites was below the PFA limit, but was considerably higher than the current EU and WHO standards. Heavy metals accumulation in vegetables tested are higher at market sites than those at the crop production sites. The contributions of these vegetables to dietary intake of Cu, Zn, Cd and Pb were 13%, 1%, 47% and 9% of provisional tolerable daily intake, respectively. The study concludes that the transportation and marketing systems of vegetables play a significant role in elevating the contaminant levels of heavy metals which may pose a threat to the quality of the vegetables with consequences for the health of the consumers of locally produced foodstuffs.     

Magnesium content in daily food portions and the influence of supplementation

Magnesium is one of the most important cations for an organism. The aim of our study is to evaluate whether the use of a magnesium formulation as a diet supplement or medical treatment is necessary. The 24-hour recall method was used to obtain information regarding the daily magnesium consumption of 949 people. The results were compared with the Estimated Average Requirement (EAR) and Recommended Daily Allowance (RDA) values. The average daily requirement for magnesium was exceeded by 292 (183 women and 109 men) of the 949 respondents. This research confirmed excessive magnesium intake by both men and women that exceeded both the EAR and the RDA. Uncontrolled, excessive dietary supplementation or medical treatment with magnesium by this group may constitute a health threat.     

Modulation of innate immune responses in the treatment of sepsis and pneumonia

In the last decades several preclinical models for sepsis have been used to study the pathophysiologic processes during sepsis. Although these studies revealed promising immunomodulating agents for the treatment of sepsis, clinical trials evaluating the efficacy of these new agents in septic patients were disappointing. It should be realized that most of the preclinical models for sepsis lack a localized infectious source from which the infection disseminates. Studies on the effects of several immunomodulating strategies have demonstrated strikingly opposite results when using models for sepsis with a more natural route of infection, such as pneumonia, and when using models for sepsis lacking an infectious focus. In this review we will compare models for sepsis and models for pneumonia. We advise to use a combination of models, including models for sepsis and models for localized infections, to test new immunomodulating strategies before starting any clinical trial evaluating a new immunomodulating therapy.     

Thiopurine metabolism and identification of the thiopurine metabolites transported by MRP4 and MRP5 overexpressed in human embryonic kidney cells

Mercaptopurines have been used as anticancer agents for more than 40 years, and most acute lymphoblastic leukemias are treated with 6-mercaptopurine (6MP) or 6-thioguanine (TG). Overexpression of the two related multidrug resistance proteins MRP4 and MRP5 has been shown to confer some resistance against mercaptopurines, which has been attributed to extrusion of mercaptopurine metabolites by these transporters. We have analyzed the mercaptopurine metabolites formed in human embryonic kidney cells and determined which metabolites are extruded by MRP4 and MRP5. Incubation with 6MP led to the formation of thioinosine and thioxanthosine metabolites and we found that thio-IMP was transported by both MRP4 and MRP5; MRP5 showed the highest transport rate. In contrast, only MRP5 transported thioxanthosine monophosphate (tXMP). During incubation with TG, the monophosphorylated form of thioguanosine was transported by both MRP4 and MRP5; the highest transport rate was for MRP4. Similarly, only 6-methyl-thio-IMP was formed during incubation with 6-methyl mercaptopurine riboside. This compound was a substrate for both MRP4 and MRP5; MRP4 showed the highest transport rate. Our results show that all major thiopurine monophosphates important in the efficacy of mercaptopurine treatment are transported by MRP4 and MRP5, although the substrate specificity of the two transporters differs in detail.