乳酸菌用作口服疫苗传递载体的研究

乳酸菌是食品级安全菌,利用乳酸菌为表达载体制成的口服疫苗安全无毒,能诱导机体产生有效的免疫应答和免疫耐受。乳酸菌口服疫苗通过胃肠粘膜进行抗原呈递,使用方便,而且较传统注射途径的免疫效果和依从性好,是理想的疫苗,有广阔的发展前景。     

Administration of D-aspartate increases D-aspartate oxidase activity in mouse liver

Oral administration of D-aspartate to mice for 2 weeks by addition of the amino acid to drinking water produced a nearly 4-fold increase in liver D-aspartate oxidase (EC 1.4.3.1) activity, whereas no increase was induced by L-aspartate administered in the same way. Administration of D-aspartate also produced a small significant increase in the kidney enzyme activity, but L-aspartate administration increased the activity as well. The enzyme activity in the brain and muscle was not affected by administration of either D- or L-aspartate. Intraperitoneal administration of D-aspartate increased the enzyme activity only in the liver, and other compounds tested, including D-glutamate and D-alanine, could not replace D-aspartate. The results indicate a specific relationship between D-aspartate and D-aspartate oxidase and suggest that the amino acid is, in fact, a physiological substrate of the enzyme.     

Intravenous infusion of PAF affects ovulation, fertilization and preimplantation embryonic development in NZB x NZW F1 hybrid mice

Platelet Activating Factor (PAF) is a bioactive phospholipid, which exhibits a variety of biological activities and plays a significant role in all aspects of reproduction. In this work, a single intravenous injection of various concentrations of PAF shortly after Human Chorionic Gonadotropin (HCG) administration as well as 24 and 48 h before HCG administration was studied in NZB x NZW F1 hybrid mice. Optimum results were observed when PAF was injected just after the administration of HCG. In this protocol, the concentrations of PAF exhibited bell-shaped response to every stage of development. Any concentration of PAF between 5.5 x 10(-11) and 5.5 x 10(-15)g/g b.w., caused an improved ovulation rate, an increased fertilization rate, an increased rate of cell cycle and an enhanced hatching blastocyst rate (P<0.05 for all stages). Injection of lyso-PAF had no effect in any stage. Our data show that the effect of PAF on early stages of embryo development in vitro is dependent on its way of administration, on the concentrations used as well as on the time PAF is injected.     

Assessment of the protective effect of vitamin E during development of experimental myocardial damage

It was shown that creatinphosphokinase activity of blood serum might be used as a criterion for evaluating the level of sparsely distributed damage in myocardium as a result of adrenaline administration. The protective effect of vitamin E under adrenaline-induced myocarditis was studied. The best effect was obtained after triple intramuscular injection of vitamin E before administration of pathological agent. Intravenous injection of the preparation has no benefits over that of intramuscular way of administration. Preventive action of vitamin E shows functioning itself in an increase of the quantity and activity of ubiquinone--the component of electron transport chain in mitochondria.     

Study on the repeated oral administration method in infant rats

The purpose of this study was to establish a new technique for repeated oral administration to infant rats. To determine the maximum volume which could be administered to infant rats the following amounts of the Chinese ink were given by metal gastric zonde for mice: 0.01, 0.04 and 0.08ml/g B. W. General conditions and the arrival distance of the Chinese ink in the gastro-intestinal tract were also observed in infant rats. The best way of administration to infant rats was decided as follows: infant rats were isolated from the dums for one hour before administration and held tenderly by their neck to sustain their mouth upward, then a metal gastric zonde for mice 2 cm long was inserted to their mouth and drug solution was injected slowly. From the observation of general conditions and pathological examination, the maximum volumes for single or repeated administration were considered to be 0.04ml/g B. W. and 0.01 ml/g B. W. respectively. Daily oral administration of 0.1ml/g B. W. of distilled water, 1% CMC solution or 1% tragacantha gum suspension for 44 days caused no effects in infant rats when administration was begun 4 days after birth. These results show that the new method for administration to infant rats is useful to evaluate the toxicity or pharmacological activity of drugs.     

Metabolism of Skin-Absorbed Resveratrol into Its Glucuronized Form in Mouse Skin

Resveratrol (RESV) is a plant polyphenol, which is thought to have beneficial metabolic effects in laboratory animals as well as in humans. Following oral administration, RESV is immediately catabolized, resulting in low bioavailability. This study compared RESV metabolites and their tissue distribution after oral uptake and skin absorption. Metabolomic analysis of various mouse tissues revealed that RESV can be absorbed and metabolized through skin. We detected sulfated and glucuronidated RESV metabolites, as well as dihydroresveratrol. These metabolites are thought to have lower pharmacological activity than RESV. Similar quantities of most RESV metabolites were observed 4 h after oral or skin administration, except that glucuronidated RESV metabolites were more abundant in skin after topical RESV application than after oral administration. This result is consistent with our finding of glucuronidated RESV metabolites in cultured skin cells. RESV applied to mouse ears significantly suppressed inflammation in the TPA inflammation model. The skin absorption route could be a complementary, potent way to achieve therapeutic effects with RESV.     

An optimal time control problem for the administration of 2′,3′-dideoxycytidine by using red blood cells as bioreactors

The problem of optimal dosage is studied for the administration of ddCyd using erythrocytes as carriers and bioreactors. The volume of erythrocytes and the initial amount of drug to be loaded have to be determined in such a way that the duration of the therapeutic effect is maximized without exceeding the toxic threshold. It is found that the optimal control is unique and it is at the upper vertex of the set of the admissible controls. A more general case is also briefly discussed.     

Immune Depletion in Combination with Allogeneic Islets Permanently Restores Tolerance to Self-Antigens in Diabetic NOD Mice

The destruction of beta cells in type 1 diabetes (T1D) results in loss of insulin production and glucose homeostasis. Treatment of non-obese diabetic (NOD) mice with immune-depleting/modulating agents (e.g., anti-CD3, murine anti-thymocyte-globulin (mATG)) can lead to diabetes reversal. However, for preclinical studies with these and other agents seeking to reverse disease at onset, the necessity for exogenous insulin administration is debated. Spontaneously diabetic NOD mice were treated with a short-course of mATG and insulin provided as drug therapy or by way of allogeneic islet implants. Herein we demonstrate that exogenous insulin administration is required to achieve disease reversal with mATG in NOD mice. Unexpectedly, we also observed that provision of insulin by way of allogeneic islet implantation in combination with mATG leads to a pronounced reversal of diabetes as well as restoration of tolerance to self-islets. Expansion/induction of regulatory cells was observed in NOD mice stably cured with mATG and allogeneic islets. These data suggest that transient provision of allogeneic insulin-producing islets might provide a temporary window for immune depletion to be more effective and instilling stable tolerance to endogenous beta cells. These findings support the use of a never before explored approach for preserving beta cell function in patients with recent onset T1D.     

Innate forms of behavior and energy metabolism in the brain of the rat after phenazepam administration in the presence of inescapable painful stimulation

Initially low level of motor search activity in test situations ("open field", maze) in rats previously grouped according to their passive behaviour with a partner-victim (Simonov method), does not essentially change after 3-week administration of phenazepam; the activity level of cytochrome oxidase in the cortex and hypothalamus is lowered. Phenazepam administration in conditions of prolonged unavoidable painful stimulation brings to a sharp increase of motor search activity and aggressive behaviour. Simultaneously the cytochrome oxidase activity increases in the same way as during a stress without phenazepam. This fact points to the independence of behavioural and biochemical effects in this case.     

Effects of dietary antibiotics on intestinal microflora in broiler chickens

Changes were examined in the intestinal microflora in broiler chickens fed a diet containing antibiotics to obtain fundamental information on the mechanisms of beneficial effect of the antibiotics upon livestock production. Three antibiotics (colistin, bacitracin, and enramycin) were employed as feed additives. Experiments were conducted with broiler chickens in two ways. In one way dietary antibiotics were fed continually at levels approved for use as feed additives for a long term. In the other they were fed the same antibiotics for a short term. Significant changes in microflora were observed mainly in such bacterial groups as aerobic bacteria and Lactobacillus. In the long term administration, three possible modes of variance in the bacterial flora were postulated: Changes directly related to the antibacterial spectrum of antibiotics. Antagonistic changes related to an ecological balance in the bacterial flora. Changes in quantitative balance of bacteria constituting each bacterial group. The change in the intestinal microflora during administration of the antibiotic diet was expressed as a complex form of these transition modes. In the short term administration, it was demonstrated that the effect of the antibiotic diet lingered even 7 days after administration. This suggests that antibiotics used as feed additives may possibly affect the stability of the intestinal microflora.     

Alloantigen-induced specific immunological unresponsiveness

When the immune system encounters alloantigen it can respond in any one of a number of different ways. The choice that is made will take into account factors such as where, when and how the contact with the alloantigen takes place, as well as the environmental conditions that prevail at the time the alloantigen is encountered. Alloantigen administration before transplantation either alone or in combination with therapeutic agents that modulate the functional activity of the responding leucocytes can be a powerful way of inducing specific unresponsiveness to alloantigens in vivo. The molecular mechanisms that influence the way the outcome of the immune response to alloantigen develops, either activation or unresponsiveness to the triggering antigen, hold the key to our ability to manipulate the immune system effectively by exposing it to donor antigen for therapeutic purposes. This review will focus on alloantigen-induced immunological unresponsiveness and how insights into the mechanisms of unresponsiveness have driven the development of novel tolerance-induction strategies that show promise for translation into the clinic in the future.     

Nonlinear coupling is absent in acute myocardial patients but not healthy subjects

We investigated whether autonomic nervous system imbalance imposed by pharmacological blockades and associated with acute myocardial infarction (AMI) is manifested as modifications of the nonlinear interactions in heart rate variability signal using a statistically based bispectrum method. The statistically based bispectrum method is an ideal approach for identifying nonlinear couplings in a system and overcomes the previous limitation of determining in an ad hoc way the presence of such interactions. Using the improved bispectrum method, we found significant nonlinear interactions in healthy young subjects, which were abolished by the administration of atropine but were still present after propranolol administration. The complete decoupling of nonlinear interactions was obtained with double pharmacological blockades. Nonlinear couplings were found to be the strongest for healthy young subjects followed by degradation with old age and a complete absence of such couplings for the old age-matched AMI subjects. Our results suggest that the presence of nonlinear couplings is largely driven by the parasympathetic nervous system regulation and that the often-reported autonomic nervous system imbalance seen in AMI subjects is manifested as the absence of nonlinear interactions between the sympathetic and parasympathetic nervous regulations.     

Influence of indole acetic acid on antioxidant levels and enzyme activities of glucose metabolism in rat liver

Indole acetic acid (IAA) is an auxin and can be synthesized in animals. This compound is metabolized in vitro by peroxidase, producing reactive oxygen species. The toxic effect of indole acetic acid in leukocytes is associated with peroxidase activities and these processes have been implicated in activation of glucose and glutamine metabolism. However, studies in vitro have shown that IAA, in absence of peroxidase, is an antioxidant almost as high in potency as those of other indolic compounds. The purpose of this study was to investigate the possible involvement of a toxic effect of indole acetic acid in the liver, as evidenced by oxidative stress and enzyme activities of the glucose pathway. The animals received IAA by subcutaneous or gavage administration in a phosphate buffered saline (the control group received only the phosphate buffered saline). The other groups received IAA at concentrations of 1 mg, 18 mg and 40 mg per kg of body mass per day. Treatments with 18 mg and 40 mg IAA decreased the activity of catalase by both subcutaneous (30% and 26%) or gavage administration (19% and 28%), respectively. A similar effect was observed on the activity of glutathione peroxidase of animals exposed to 18 mg and 40 mg IAA: A decrease of 34% and 29%, respectively, for subcutaneous administration and a decrease of 29% and 25%, respectively, for gavage administration. However, in neither source of administration did the acid alter superoxide dismutase, glutathione reductase and myeloperoxidase activities. Another alteration was observed in respect of reduced glutathione content in this organ. The lipid peroxidation level showed a significant decrease with subcutaneous (30%, 29% and 24%) and gavage administration (25%, 26% and 24%) using 1 mg, 18 mg and 40 mg of IAA, respectively compared with the control. The reduced glutathione content and catalase activity in the plasma were not altered by either of the two methods of administration. In addition to these findings, after subcutaneous or gavage administration of IAA, the activities of hepatic enzymes of glucose metabolism were not affected (glucokinase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase and citrate synthase). Evidence is presented herein that IAA did not have a pro-oxidant effect in the liver as deduced from a reduction of catalase and glutathione peroxidase activities, a decrease of lipid peroxidation content and no alteration of the pool of reduced glutathione. The effects of IAA were independent of the way of administration.     

Inhibition of mammary tumorigenesis in virgin rats by adoptive transfer of splenocytes from parous donors

Summary Splenocytes from parous rats have been previously found to have cytotoxic activity against mammary tumor cells in vitro. Experiments were carried out to determine if this pregnancy-induced cytotoxic nature of the splenocytes is inherent and transferable. Splenocytes from parous rats were adoptively transferred to a group of virgin rats. Another group of age-matched, virgin rats received splenocytes from virgin donors in a similar way. After a period of rest, at the age of 55 days, the rats belonging to both of the groups, received 7,12-dimethylbenz(a)anthracene (DMBA) intragastrically. A third group of untreated virgin rats were also given the chemical carcinogen the same way as above and were considered as intact controls. The rats were monitored for development and growth of mammary tumor from 60 days of DMBA administration. After 4 months of DMBA administration the rats were sacrificed and mammary glands were examined for tumors. Mammary glands with no visible tumors were taken for whole mount preparation, to be examined for microscopic lesions. The results showed that 33 of 41 intact control rats, developed tumor and 27 of the 34 rats that received spleen cells from virgin rats developed tumors. Of the rats that received spleen cells from parous rats, only 18 out of 37 rats developed tumors, indicating an inhibition of tumor induction in these rats. Growth rate of the tumors in this group was also slower than in the control groups.This research was supported by USPHS grant CA 3613906 awarded by the National Cancer Institute     

Acute toxicity and radioprotective effectiveness of gammaphos on intramuscular administration to mice

In experiments on mice it was shown that acute toxicity of gammaphos (WR-2721) was 790 mg/kg and 862 mg-kg after intraperitoneal and intramuscular administration, respectively. Gammaphos in the dose of 100 mg/kg, injected intramuscularly, increased the radioresistance of mice in nearly the same way as cystamine, in the dose of 150 mg/kg, did. The increase in the dose of gammaphos up to 200 or 300 mg/kg, injected intramuscularly, enhanced the radioprotective effect. No change was observed in the radioprotective efficiency of gammaphos after intramuscular injection as compared to intraperitoneal administration of the protective agent in the same dose.     

Impact of pharmacogenomics on clinical practice in oncology

Multiple drug strategies for many cancer types are now readily available and there is a clear need for tools to inform decision making on therapy selection. Although there is still a long way to go before pharmacogenomics achieves the goal of individualized selection of cancer treatment, promising progress is being made. Genetic testing for thiopurine methyltransferase (TPMT) variant alleles in patients prior to mercaptopurine administration, and for UGT1A1*28 in patients prior to administration of irinotecan therapy, along with the instigation of genotype-guided clinical trials (e.g. TYMS) are important advances in cancer pharmacogenomics. Markers for the toxicity and efficacy of many oncology drugs remain unknown; however, the examples highlighted here suggest progress is being made towards the incorporation of pharmacogenomics into clinical practice in oncology.     

Promoting effect of portacaval anastomosis in experimental hepatic carcinogenesis

A promoting effect of portocaval anastomosis in a triphasic model of rat hepatocarcinogenesis is demonstrated since after initiation and selection premalignant lesions and hepatocellular carcinomas increase. This demonstrates that chronic administration of an exogenous compound is not the only way to promote cancer development.     

Evaluation of immunomodulatory effects of nisin-containing diets on mice

The effect of nisin on the immune response of mice was studied. Nisin (in the form of the commercial preparation Nisaplin) was incorporated in the diet of experimental mice which were fed for 30, 75 or 100 days. Short-term administration of diets containing Nisaplin induced an increase of both CD4 and CD8 T-lymphocyte cell counts and also a decrease of B-lymphocyte counts. After prolonged diet administration, T-cell counts returned to control levels. Normal levels of B-lymphocytes were also reached after prolonged administration of the lower (but not the higher) Nisaplin concentration. The macrophage/monocyte fraction isolated from peripheral blood became significantly increased after long-term administration (100 days) of Nisaplin-containing diets in a concentration-dependent way. Although the number of peritoneal cells was not affected by the diets, the phagocytic activity of peritoneal cells decreased after prolonged administration of low (but not high) Nisaplin doses.     

Towards the therapeutic use of intranasal neuropeptide administration in metabolic and cognitive disorders

The nose provides an effective way for delivering neuropeptides to the central nervous system, bypassing the blood-brain barrier and avoiding systemic side effects. Thereby intranasal neuropeptide administration enables the modulation of central nervous signaling pathways of body weight regulation and cognitive functions. Central nervous control of energy homeostasis is assumed to rely on hypothalamic neuropeptidergic pathways that are triggered by the peripheral adiposity signals insulin and leptin conveying the amount of body fat to the brain. Melanocortins, including alpha-melanocyte stimulating hormone (alpha-MSH), are essential for inducing anorexigenic/catabolic effects, i.e. for inhibiting caloric intake and increasing energy expenditure. Insulin, in addition to its function as an adiposity signal, also influences memory formation. Here we present a series of studies on the intranasal administration of MSH/ACTH(4-10), a melanocortin receptor agonist, and of insulin. Prolonged administration of MSH/ACTH(4-10) induced weight loss in normal-weight, but not in overweight humans. Intranasal insulin reduced body fat and improved memory functions in the absence of adverse peripheral side effects. Our results may contribute to the future development of therapeutic strategies in disorders like obesity and cognitive impairments that derive from dysfunctions of central nervous neuropeptidergic pathways.     

Mouse genetic models for aneuploidy induction in germ cells

Rodents have been successfully used as models to identify risks of chemical exposures or age to aneuploidy induction in germ cells, which may be transmitted to the progeny. For this administration in vivo as well as exposures to in vitro maturing germ cells have been useful. Genetic models involving mice with structural chromosomal rearrangements and transgenic animals have the potential to model conditions predisposing to aneuploidy in one or both sexes, and in this way to identify potential targets for aneugens and gender-effects. The review provides an overview of mouse genetic models for aneuploidy induction in mammalian germ cells and discusses perspectives for combining genetic with experimental approaches in aneuploidy research.