Suppression In Animals Research Articles

The impact of suppressing puberty on neuropsychological function: A review.

Concerns have been raised regarding the impact of medications that interrupt puberty, given the magnitude and complexity of changes that occur in brain function and structure during this sensitive window of neurodevelopment. This review examines the literature on the impact of pubertal suppression on cognitive and behavioural function in animals and humans. All studies reporting cognitive impacts of treatment with GnRH agonists/antagonists for pubertal suppression in animals or humans were sought via a systematic search strategy across the PubMed, Embase, Web of Science and PsycINFO databases. Sixteen studies were identified. In mammals, the neuropsychological impacts of puberty blockers are complex and often sex specific (n = 11 studies). There is no evidence that cognitive effects are fully reversible following discontinuation of treatment. No human studies have systematically explored the impact of these treatments on neuropsychological function with an adequate baseline and follow-up. There is some evidence of a detrimental impact of pubertal suppression on IQ in children. Critical questions remain unanswered regarding the nature, extent and permanence of any arrested development of cognitive function associated with puberty blockers. The impact of puberal suppression on measures of neuropsychological function is an urgent research priority.

The anorexic effect of DL-fenfluramine is dependent on animals' habituation to different food types.

As rates of obesity and diabetes have increased dramatically over the past few decades, the use of anti-obesity drugs has now become a routine therapeutic measure. However, the pharmacological effects of chronic use of these drugs in humans frequently lead to reduced efficacy in reducing appetite and body weight through as-yet-unidentified mechanisms. An example of this can be found in animal studies where the appetite suppressant DL-fenfluramine (FEN) is chronically administered and its tolerance develops in animals and humans. The appetite effects of FEN are typically measured in several animal studies by the feeding changes in a balanced standard diet. To determine whether FEN differentially altered appetite suppression in animals with long-term expression with different macronutrient diet compositions, its anorexic effects were measured specifically in male rats that had previously been chronically maintained on normal chow (NC) or a high-fat and high-carbohydrate western diet (WD). Three experiments were conducted by feeding the animals either NC or WD for 1 month to habituate them with their diet. Animals maintained on either NC or WD were subsequently offered both diet options ad libitum for a 2- or 7-day adaptation period while receiving daily systemic FEN treatment. The results suggested that long-term habituated food affected the food preference of animals and their appetite even after chronic systemic FEN administration. Therefore, the effectiveness and success or failure of repeated use of chronic anti-obesity drugs may depend on habituated food type. The appetite suppressant effect was found to be determined by the palatability of a specific macronutrient and the habituated food rather than by a change in the concentration of the administered FEN. This results in a critical analysis of the rationale for taking medication considering the patient's past dietary habits to achieve successful weight loss.

Effects of silica-rich water on systemic and peritoneal inflammation in rats exposed to chronic low-level (900-MHz) microwave radiation.

Immunomodulating effect of silica-rich water represents a novel field for research, especially regarding its features toward environmental pollutants. The aim of our study was to evaluate the effects of silica-rich water intake on systemic and peritoneal inflammation in rats that were chronically exposed to the low-level microwave (MW) radiation from mobile phones. Wistar Albino rats were exposed to 900 MHz MW radiation for 3 months. The four-treatment model involved rats with standard water (SW) or experimental silica-rich water intake (EW). Peritoneal macrophages (PMs) were harvested using peritoneal lavage and divided into non-stimulated and lipopolysaccharide (LPS) stimulated subgroups. The MW-exposed rats with silica-rich water (MW+EW) had lower serum tumor necrosis factor α (TNF-α) and interleukin 2 (IL-2) levels, but higher IL-10 levels, than MW+SW rats (p < 0.05). The higher TNF-α production by non-stimulated MW exposed PMs was ameliorated by the silica-rich water (p < 0.01). The MW exposition suppressed LPS potential for TNF-α synthesis in both water type groups, with greater suppression in animals that took standard water. Our results show the modulating effect of silica-rich water toward MW-induced systemic and peritoneal inflammation, which reflects the water ability to shape monocyte plasticity, thereby altering the balance between their proinflammatory and anti-inflammatory properties.

Xenobiotic and Immune-Relevant Molecular Biomarkers in Harbor Seals as Proxies for Pollutant Burden and Effects.

Harbor seals are exposed to increasing pressure caused by anthropogenic activities in their marine environment. Persistent organic pollutants (POPs) and trace elements are hazardous contaminants that accumulate in tissues of harbor seals. POPs and trace elements can negatively affect the immune-system and have been reported, e.g., to increase susceptibility to viral infections in seals. Biomarkers of the xenobiotic metabolism, cytokines, and heat-shock protein as cell mediators of the immune-system were established to evaluate the impact of environmental stressors on harbor seals. Harbor seals (n = 54) were captured on sandbanks in the North Sea during 2009-2012. Health assessments, including hematology, were performed, and RNAlater blood samples were taken and analyzed using quantitative polymerase chain reaction. Normalized transcript copy numbers were correlated to hematology and POP concentration in blood and trace metals in blood and fur. A significant correlation between xenobiotic markers and contaminant burden was found. Significant interrelationships between markers and POP compounds, as well as with season, weight, and hematology values, indicate that biomarkers reflect pollutant exposure and effects. A significant relationship between cortisol levels and heat-shock protein expression was observed indicating stress experienced during restraint of the seals. Interleukin-10 transcription showed significant correlations with trace elements in fur pointing toward immune regulatory effects of metal exposure. The molecular markers prove to be an important noninvasive tool that reflects contaminant exposure and the impact of anthropogenic stressors in seal species. The connection between interleukin-2, xenobiotic markers, and pollutants may indicate immune suppression in animals exposed to contaminants with subsequent susceptibility to inflammatory disease.

Does patterned afferent stimulation of sacral dermatomes suppress urethral sphincter reflexes in individuals with spinal cord injury?

Dyssynergic contractions of the external urethral sphincter prevent efficient bladder voiding and lead to numerous health concerns. Patterned electrical stimulation of the sacral dermatomes reduces urethral sphincter spasms and allows functional bladder emptying in cats after chronic SCI. Reflex suppression in animals is strongly dependent on stimulus location and pattern. The purpose of this study was to determine whether the stimulation patterns and locations effective in animals suppress urethral sphincter spasms in humans with SCI. Ten subjects with chronic SCI underwent bladder filling to elicit distention-evoked contractions. During reflex contractions patterned electrical stimulation was applied to the S2 or S3 dermatome in random 25-sec intervals. Bladder and sphincter pressures were simultaneously recorded and compared between control and afferent stimulation periods. Six of the 10 subjects demonstrated both reflex bladder and sphincter contractions with bladder filling. No significant reduction in urethral pressure was observed during stimulation for any stimulus locations and patterns tested. Stimulation parameters and locations effective in SCI animals did not suppress reflex sphincter activity in these human subjects. It is likely that a broader set of stimulus patterns and dermatome locations will need to be tested to find the effective combination in humans.

Skeletal effects of zoledronic acid in an animal model of chronic kidney disease

Bisphosphonates reduce skeletal loss and fracture risk, but their use has been limited in patients with chronic kidney disease. This study shows skeletal benefits of zoledronic acid in an animal model of chronic kidney disease. Bisphosphonates are routinely used to reduce fractures but limited data exists concerning their efficacy in non-dialysis chronic kidney disease. The goal of this study was to test the hypothesis that zoledronic acid produces similar skeletal effects in normal animals and those with kidney disease. At 25 weeks of age, normal rats were treated with a single dose of saline vehicle or 100 μg/kg of zoledronic acid while animals with kidney disease (approximately 30% of normal kidney function) were treated with vehicle, low dose (20 μg/kg), or high dose (100 μg/kg) zoledronic acid, or calcium gluconate (3% in the drinking water). Skeletal properties were assessed 5 weeks later using micro-computed tomography, dynamic histomorphometry, and mechanical testing. Animals with kidney disease had significantly higher trabecular bone remodeling compared to normal animals. Zoledronic acid significantly suppressed remodeling in both normal and diseased animals yet the remodeling response to zoledronic acid was no different in normal and animals with kidney disease. Animals with kidney disease had significantly lower cortical bone biomechanical properties; these were partially normalized by treatment. Based on these results, we conclude that zoledronic acid produces similar amounts of remodeling suppression in animals with high turnover kidney disease as it does in normal animals, and has positive effects on select biomechanical properties that are similar in normal animals and those with chronic kidney disease.

Natural Products for Medicine

Throughout human history, natural products—including terrestrial plants, animal products, marine organisms, and products of microorganismal fermentation—have been used in traditional medicines. This historical experience with natural products as therapeutic agents has evolved to sophisticated isolation of active chemical entities from ethnopharmacological plants with the effect that, in modern medicine, natural products are increasingly the primary sources in early drug discovery. The population is aging in many modern societies and is linked to steadily increasing morbidity rates of cancer and cerebrovascular disease, thus mandating the importance of better preventive as well as therapeutic options. Many medically advanced societies are exploring the adjunctive use of western and oriental medicine alternatives, enhancing the demand for natural products. While evidence-based data is still scant in the field of alternative medicines, in this special issue we have the pleasure of sharing with our readers many scientific articles on natural products with potential medicinal use. This special issue contains 6 review articles and 19 original peer-reviewed papers. The reviews included summarize such diverse topics as the biological and pharmacological effects of ginsenoside Rb1, isolated from red ginseng root, on skin damage (Y. Kimura et al.); tumor suppression in animals by a fruit pulp containing high amounts of β-cryptoxanthin and hesperidin (T. Tanaka et al.); the favorable effects of purple corn flower in treatment of infectious diseases (J. B. Hudson); the biomechanisms and clinical outcome of Rhus verniciflia extract in patients (W. Choi et al.); the safety of cruciferous plant extracts (O. Scott et al.); and the antitumor activity of artemisinin and its analogs (M. P. Crespo-Ortiz and M. Q. Wei). The original articles embrace a wide variety of topics, such as apoptosis, suppression of cell proliferation and tumorigenesis (Y. Hu et al., H. Kurose et al., A. Lerner et al., Booth et al., Kita et al., Mohd et al., and G. M. Geetha et al.), the antibacterial/antifungal/anti-inflammation/antioxidative characteristics of natural extracts (E. Biazar et al., Y.-S. Lee et al., Y. Hu et al., A. Cha et al., H. Sun et al., and P.-F. Kao et al.), cardiovascular activity of specific natural products (K. Awang et al.), the effects of extracts on blood parameter levels in diabetic patients (T. Klangjareonchai and C. Roongpisuthipong), examination of isolation techniques (N. A. Mahyudin et al.), enzymatic activity (B. Elya et al.) and metabolism of certain extracts (Y. Shimoda et al.); and specific effects of some natural products on aryl hydrocarbon receptor expression (H. M. Korashy et al.). We would like to thank the authors for their timely contributions. Finally, we also thank all reviewers for their hard work questioning, pruning, and refining these articles. Masa-Aki Shibata Ikhlas A. Khan Munekazu Iinuma Tomoyuki Shirai

Deoxynivalenol exposure assessment in a cohort of pregnant women from Bradford, UK

Deoxynivalenol (DON) is a ubiquitous contaminant of cereal crops in temperate regions of the world. It causes growth faltering and immune suppression in animals. Limited information is available on DON exposure in UK subpopulations. The objective of this study was to provide DON exposure assessment in a subset of pregnant women scheduled for an elective caesarean in a large multi-ethnic mother/infant birth cohort from Bradford, UK. Women aged 16–44 years (n = 85) provided a urine sample for DON analysis in the last trimester of pregnancy, and concurrently completed a food-frequency questionnaire (FFQ). The urinary DON biomarker was detected in all measured samples (geometric mean (GM) = 10.3 ng DON mg−1 creatinine, range = 0.5−116.7 ng mg−1). Levels were higher in women classified as South Asian in origin (GM: 15.2 ng mg−1; 95% CI = 10.7−21.5 ng mg−1) compared with non-South Asians (GM = 8.6 ng mg−1; 95% CI = 6.6−11.8 ng mg−1), p = 0.02). Estimated DON intake from FFQ data and typical levels of DON contamination of food suggest that this was mainly due to higher levels of exposure from bread, particularly daily intake of DON from chapattis in South Asians (estimated mean = 2.4 µg day−1; 95% CI = 1.2, 3.7 µg day−1) compared with non-South Asians (estimated mean = 0.2 µg day−1; 95% CI = 0−0.4 µg day−1), p < 0.001. This is the first biomarker demonstration of DON exposure in pregnant women, and several urinary DON levels were the highest ever recorded in any study. A larger survey within this birth cohort is warranted to investigate any potential risk to mothers and their babies, from DON exposure during pregnancy.

Tim-3-Galectin-9 pathway involves the suppression induced by CD4 +CD25 + regulatory T cells

CD4 +CD25 + regulatory T cells (Tregs) are considered to play a key role as suppressors of immune-mediated reactions. The mechanisms of this suppression in animals and patients with autoimmune, allergic or oncogenic diseases have been investigated under various conditions. However, the precise mode of suppression by CD4 +CD25 + Tregs is still not clear. In this report, Tim-3-Galectin-9 pathway was explored as one of the mechanisms for the suppression and cytotoxicity induced by Tregs. Here, we demonstrated that Galectin-9 was expressed on CD4 +CD25 + Tregs by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Interestingly, blocking Tim-3-Galectin-9 pathway resulted in an obvious decreased suppression activity of Tregs and enhanced Th1 cytokine level in vitro. Furthermore, blocking Tim-3-Galectin-9 pathway negated prolonged survival of allogeneic skin grafts induced by CD4 +CD25 + Tregs in vivo. Our results suggest that Tim-3-Galectin-9 pathway involves the function of CD4 +CD25 + Tregs.

Vitamin D Receptor is a Novel Drug Target for Ovarian Cancer Treatment

Ovarian cancer is the leading cause of death among gynecological malignancies in the US and the poor outcome of current treatments necessitates the development of novel therapeutic strategies to fight against it. Epidemiological data indicate a positive association between higher latitude and ovarian cancer incidence and mortality rates, suggesting that vitamin D insufficiency may contribute to ovarian cancer development. Recent studies in the authors' laboratory showed that multiple ovarian cancer cell lines respond to the active form of vitamin D, 1alpha,25-dihydroxyvitamin D(3), for growth suppression. Mechanistic studies identified vitamin D-regulated genes with established functions in ovarian tumorigenesis as mediators for the growth suppression. While increased p27 protein stability and transcriptional up-regulation of GADD45 are responsible for 1alpha,25-dihydroxyvitamin D(3)-induced cell cycle arrest at G1/S and G2/M checkpoints, respectively, the hormone-induced apoptosis in ovarian cancer cells involves the down regulation of the mRNA stability of telomerase catalytic subunit. More importantly, preclinical studies showed that the synthetic vitamin D analog EB1089 effectively suppressed the growth of human ovarian tumor xenografts in mice. The tumor suppression is associated with an increase in apoptotic rate and a decrease in cell proliferation, suggesting that the molecular information can be translated into ovarian tumor suppression in animals. Based on these studies, we conclude that the vitamin D receptor that mediates these anti-tumor effects represents a novel molecular target for the development of new drugs for ovarian cancer. We predict that receptor-based drug discovery will lead to the successful development of more potent and safer vitamin D analogs for the treatment of this deadly disease.

Bacterial and Plant Enterotoxin B Subunit–Autoantigen Fusion Proteins Suppress Diabetes Insulitis

Several bacterial and plant enterotoxin B subunit-islet autoantigen fusion proteins were compared for their ability to serve as islet autoantigen carriers and adjuvants for reduction of pancreatic islet inflammation associated with type 1 diabetes. The cholera toxin B subunit (CTB), the heat-labile toxin B subunit from enterotoxigenic Escherichia coli (LTB), the Shigella toxin B subunit (STB), and the plant toxin ricin B subunit (RTB) were genetically linked to the islet autoantigens proinsulin (INS) and glutamic acid decarboxylase (GAD). The adjuvant-autoantigen gene fusions were transferred to a bacterial expression vector and the corresponding fusion proteins synthesized in E. coli. The purified adjuvant-autoantigen proteins were fed to 5-wk-old nonobese diabetic (NOD) mice once a week for 4 wk. Histological examination of pancreatic islets isolated from inoculated mice showed significant levels of insulitis reduction in comparison with uninoculated mice. The ratio of serum anti-INS and anti-GAD IgG2c to IgG1 antibody isotype titers increased in all ligand-autoantigen inoculated animal groups, suggesting an increase in effector Th2 lymphocytes in B subunit-mediated insulitis suppression. The results of these experiments indicate that bacterial and plant enterotoxin B subunit ligand-autoantigens enhance insulitis reduction in NOD mice. This research prompts further exploration of a multiadjuvant/autoantigen co-delivery strategy that may facilitate type 1 diabetes prevention and suppression in animals and humans.

982. Adaptive Immune System Down-Regulates Transgene Expression from Adenovirally Infected Neurons in the Brain In Vivo

Studies on mechanisms by which the immune system eliminates virally infected cells from the brain have been limited by the difficulty in differentiating damage induced by a replicating virus from that induced by the immune system. To understand the cellular and molecular mechanisms by which the immune system can control virus gene expression in neurons we utilized a replication incompetent virus and a marker transgene expressed exclusively in neurons as a surrogate for expression of genes from the viral genome. Upon systemic immunization against the virus, we demonstrate that CD4+ and CD8+ T cells are necessary to eliminate expression of the marker gene expression from the CNS through a mechanism dependent upon IFN|[gamma]|, perforin and tumor necrosis factor |[gamma]|; almost complete loss of expression ensues at 30 days post-immunization and does not recover up to a year later. To differentiate whether the immune system eliminates transgene expression through killing of transduced cells, or functional inhibition of expression from the viral genome, we performed detailed anatomical analysis, studies in mice deficient in important immunological mediators, studied simultaneously the expression of marker genes from the viral genome and the cellular genome of infected cells, and performed adoptive transfer and immune-suppression experiments. Detailed confocal microscopical analysis discovered that CD8 and CD4 T cells infiltrated specifically infected regions of the brain, established close anatomical contacts with infected neurons, and could be detected within the infected brains for up to one year after the systemic immunization. In addition, we detected a significant infiltration of macrophages, which at later stages could be seen phagocytosing transduced cells, illustrating terminal stages of cell death of adenovirally transduced brain cells. Using ROSA26 mice and viruses expressing Cre, we demonstrated that the immune system abolished expression from both the viral genome and the cellular genome, supporting the idea that at least some loss of marker gene expression is due to target cell death. Surprisingly however, while adoptive transfer of CD4+ and CD8+ T cells induced a transient loss of viral genome expression, immune suppression of animals more than two months post-immunization only induced a partial recovery. Thus, we demonstrate that CD4+ and CD8+ T cells eliminate viral gene expression from the brain through mechanisms that require constant surveillance of the CNS, and are mediated in part through the elimination of infected cells and partly, through the functional inhibition of gene expression. These data have important implications for our understanding of mechanisms by which the immune system clears virally infected cells from the brain, and consequently the safety of long term gene therapy strategies for the treatment of brain diseases. Finally, our data also appear to throw light on mechanisms by which the immune system controls 'slow replicating' viruses such as the JC virus, or HSV-1, which remain latent in the human nervous system for long periods of time, but reactivate upon immune-suppression.

Proteolytic inactivation of cytokines by Pseudomonas aeruginosa

Pseudomonas aeruginosa alkaline protease and elastase are thought to contribute to bacterial invasiveness, tissue damage, and immune suppression in animals and patients infected with the bacterium. This study examined the ability of the two proteases to inactivate a number of cytokines that mediate immune and inflammatory responses. Human recombinant gamma interferon (rIFN-gamma) and human recombinant tumor necrosis factor alpha were inactivated by both proteases. Murine rIFN-gamma was relatively resistant to alkaline protease but was inactivated by elastase, and human recombinant interleukin-1 alpha and recombinant interleukin-1 beta were resistant to the effects of both proteases. Western immunoblots suggested that cytokine inactivation by these proteases, where it occurred, required only limited proteolysis of the polypeptides. The ability of different P. aeruginosa strains to inactivate IFN-gamma appeared to require the production of both proteases for optimum activity. These results indicate that in vitro cytokine inactivation by Pseudomonas proteases is selective, requires only limited proteolysis, and in certain instances reflects the cooperative effects of both proteases.

Reflex adrenergic inhibition of gastric motility by nociceptive intestinal stimulation and peritoneal irritation in the cat.

The effects on gastric motility of nociceptive stimulation to jejunum and colon were studied in vagotomized anesthetized cats. Mechanical nociceptive stimulation and diathermy of the jejunum and proximal colon elicited reflex gastric inhibition that was significantly more pronounced than that obtained by stimulation of distal colon. Similarly differentiated reflex responses were induced by electric afferent stimulation of nerves from the respective intestinal segments. Strong nociceptive stimuli from the abdominal cavity, induced by peritonitis, completely blocked vagal excitatory influences on gastric motility, as did multiple nerve stimulation. The gastric inhibitory response to abdominal irritation persisted after adrenalectomy but was eliminated during spinal anesthesia or adrenergic blockade. During gastric suppression in animals with abdominal peritonitis cholinergic potentiation with synstigmin administration could only modestly increase gastric tone. It is concluded that intestinal nociceptive stimulation causes gastric inhibition via sympathetic reflex arches that are segmentally differentiated. These adrenergically mediated inhibitory reflexes are powerful enough to block completely myenteric cholinergic neurons. The results suggest that adrenergic blockade or spinal anesthesia is the logical procedure for treating postoperative adrenergic gastric inhibition. The presently studied sympatho-sympathetic adrenergic reflexes seem to work in synergism with sympatho-vagal nonadrenergic reflexes in suppressing gastric motility during paralytic ileus.

FACTORS AFFECTING THE DURATION OF INTESTINAL PERMEABILITY TO MACROMOLECULES IN NEWBORN ANIMALS

Summary1. In several species, partial, or even complete passive immunization of the offspring is achieved through maternal antibodies which are concentrated in the colostrum. Failure to obtain sufficient colostrum renders newborn farm animals highly susceptible to systemic and enteric infection with E. coli.2. A significant number of colostrum‐fed calves nevertheless develop colisepticaemia and many of these animals are hypo‐ or even agammaglobulinaemic. A premature termination of intestinal ability to absorb colostral antibodies (closure) may be responsible for some of these cases.3. Pharmacological doses of certain exogenous corticosteroids are capable of inducing premature closure in rats. It is not certain though whether exogenous corticosterone can induce precocious closure in rat pups or whether exogenous corticosteroids can induce closure in members of other mammalian orders. Corticosteroid levels, however, may influence the efficiency of immunoglobulin absorption. Attempts to delay closure with adrenal suppression in animals with short immunoabsorptive periods have not been effective.4. In piglets, but not in puppies or calves, starvation can postpone closure for several hours and consumption of food may be necessary before closure can occur.5. Closure in the rat and pig apparently takes place by different methods.