Significant Protection In Terms Research Articles

Evaluation of the efficacy of an autogenous Escherichia coli vaccine in broiler breeders

ABSTRACTIn poultry production Escherichia coli autogenous vaccines are often used. However, the efficacy of autogenous E. coli vaccinations has not been evaluated experimentally in chickens after start of lay. The aim of the present study was to evaluate the protective effect of an autogenous E. coli vaccine in broiler breeders. Three groups of 28-week-old broiler breeders (unvaccinated, vaccinated once and twice, respectively) were challenged with a homologous E. coli strain (same strain as included in the vaccine) or a heterologous challenge strain in an experimental ascending model. The clinical outcome was most pronounced in the unvaccinated group; however, the vast majority of chickens in the vaccinated groups had severe pathological manifestations similar to findings in the unvaccinated group after challenge with a homologous as well as a heterologous E. coli strain. Although significant titre rises in IgY antibodies were observed in the twice vaccinated group, antibodies did not confer significant protection in terms of pathological impact. Neither could transfer of maternal-derived antibodies to offspring be demonstrated. In conclusion, with the use of the present model for ascending infection, significant protection of an autogenous E. coli vaccine against neither a homologous nor a heterologous E. coli challenge could not be documented.

The Protective Effect of Poloxamer-188 on Platelet Functions.

Poloxamer-188 (MST-188) is effective in the repair/recovery of damaged cell membranes. MST-188 is a promising agent for protecting blood cell viability. The aim of the study is to test the hypothesis that MST-188 can extend the duration of platelet function. Blood samples were collected from 20 healthy volunteers. MST-188 (10 or 2 mg/mL) containing platelet-rich plasma (PRP) was prepared with 2 procedures. First, PRP prepared from MST-188 added whole blood (WB); second, MST-188 was added to PRP. These were referred to MST-188-WB preparation (WBP) and MST-188-PRP preparation (PRPP), respectively. For control, saline was used in the same manner. Agonist-induced aggregation (AIA) studies were performed at 30, 180, and 300 minutes using Platelet Aggregation Profiler (PAP-8) aggregometer (Bio/Data Corporation, Horsham, Pennsylvania) and Adenosine diphosphate (ADP), arachidonic acid, collagen, and epinephrine as agonists at final concentration of 20 µM, 500 µg/mL, 0.19 mg/mL, and 100 µM, respectively. There was a protective effect of MST-188 on ADP and collagen AIA. At 300 minutes, ADP AIA was found to be 50.2% higher than saline control in 2-mg WBP, 43% at 10-mg PRPP, and 10.4% at 2-mg PRPP. Protective effect of on collagen AIA was 65.9% in 2-mg WBP, 42.74% at 10-mg PRPP, and 11.42% at 2-mg PRPP. In comparison between 30 and 300 minutes, MST-188 showed significant protection in terms of ADP and collagen receptors and for both types of preparations (WBP and PRPP). The protective effects of MST-188 on ADP- and collagen-induced platelet aggregation may contribute to the preservation of platelet functionality upon storage in blood banks.

Cellular responses against Schistosoma mansoni in immunized Balb/c mice with soluble proteins from intermediate host, Biomphalaria pfeifferi

Scores of millions of people around the world are infected by Schistosoma mansoni causing considerable morbidity, mortality and loss of productivity. Safe chemotherapeutic agents have been used though there are challenges of re-infection due to resistance. Both epidemiological and experimental data suggest that acquired cell mediated immunity play significant roles in regulating the intensity of S. mansoni infection as well as its patho-physiologic sequelae. Improved control of this trematode parasite may be obtained with immunization to enhance the resistance of individuals to risk of infection. This study investigated the cellular responses of mice immunized with soluble proteins from foot and digestive gland of the vector snail and challenged with S. mansoni. The proteins were used to immunize the experimental groups then challenged with the S. mansoni. The experimental groups were FT (immunized with foot protein) and DG (immunized with digestive gland). The parameters, which were analyzed to demonstrate protection, included; the worm counts and cellular (IFN-γ, IL-5 cytokines) responses. It was observed that, the experimental groups showed significant protection in terms of worm reduction and immune responses. The group vaccinated with foot protein showed higher protection (87.5%) as compared to the group vaccinated with the digestive gland (50%) in terms of worm reduction. Cytokines (IFN-γ and IL-5) production was present in different levels during the assay time points which showed an aspect of protection. The Foot protein of the vector showed more immunizing power than the digestive gland. Research towards utilizing the two proteins as feasible vaccine candidates is encouraged.

Contribution of reactive oxygen species to UV-B-induced damage in bacteria

The present work aimed to identify the reactive oxygen species (ROS) produced during UV-B exposure and their biochemical targets, in a set of bacterial isolates displaying different UV susceptibilities. For that, specific exogenous ROS scavengers (catalase/CAT, superoxide dismutase/SOD, sodium azide and mannitol) were used. Biological effects were assessed from total bacterial number, colony counts and heterotrophic activity (glucose uptake and respiration). DNA strand breakage, ROS generation, oxidative damage to proteins and lipids were used as markers of oxidative stress. Sodium azide conferred a statistically significant protection in terms of lipid oxidation and cell survival, suggesting that singlet oxygen might play an important role in UV-B induced cell inactivation. Mannitol exerted a significant protection against DNA strand breakage and protein carbonylation, assigning hydroxyl radicals to DNA and protein damage. The addition of exogenous CAT and SOD significantly protected the capacity for glucose uptake and respiration, suggesting that superoxide and H2O2 are involved in the impairment of activity during UV-B exposure. The observation that amendment with ROS scavengers can sometimes also exert a pro-oxidant effect suggests that the intracellular oxidant status of the cell ultimately determines the efficiency of antioxidant defenses.

Lack of protective efficacy in buffaloes vaccinated with Fasciola gigantica leucine aminopeptidase and peroxiredoxin recombinant proteins

Gene coding for leucine aminopeptidase (LAP), a metalloprotease, was identified in the tropical liver fluke, Fasciola gigantica; that on sequence analysis showed a close homology (98.6%) with leucine aminopeptidase of the temperate liver fluke, Fasciola hepatica. The recombinant leucine aminopeptidase protein was expressed in Escherichia coli. F. gigantica peroxiredoxin, a hydrogen peroxide scavenger and an immunomodulating protein, was also cloned and expressed in E. coli. A vaccination trial in buffaloes was conducted with these two recombinant proteins, with 150 and 300μg of leucine aminopeptidase and a cocktail of 150μg each of recombinant leucine aminopeptidase and peroxiredoxin in three groups, respectively. Both Th1- and Th2-associated humoral immune responses were elicited to immunization with these antigens. A challenge study with 400 metacercariae did not show a significant protection in terms of reduction in the worm burden (8.4%) or anti-fecundity/embryonation effect in the immunized groups, as to the non-immunized control animals. Our observations in this buffalo vaccination trial are contrary to the earlier promise shown by leucine aminopeptidase of F. hepatica as a leading candidate vaccine molecule. Identification of leucine aminopeptidase gene and evaluation of the protein for its protective efficacy in buffaloes is the first scientific report on this protein in F. gigantica.

Evaluation of immune responses and protective efficacy in a goat model following immunization with a coctail of recombinant antigens and a polyprotein of Mycobacterium avium subsp. paratuberculosis

The protective efficacy of four recombinant antigens (85A, 85B, superoxide dismutase [SOD], and a fusion polypeptide [Map74F]) of Mycobacterium avium subsp. paratuberculosis (MAP) along with the adjuvant dimethydioctadecyl ammonium bromide (DDA) was assessed in a goat challenge model. Animals were immunized with the four antigens with adjuvant DDA (Group I, eight goat kids) or without the adjuvant (Group II, eight goat kids) or adjuvant only (Group III, nine goat kids). Animals were boostered 3 weeks after the primary vaccination and challenged 3 weeks after the booster. Significant antigen-specific lymphoproliferation was observed in the immunized animals 3 weeks after the booster immunization. This response increased further at 4 weeks after the booster. Similarly, antigen-specific IFN-γ responses increased in the immunized animals 3 weeks after the booster. The response was significantly higher for 85A and Map74F at 10 weeks after primary vaccination (APV) in Group I animals compared to the other two groups. CD4 + T-cell populations were higher in the vaccinated animals from 6 to 10 weeks APV than those of the control animals. A significant increase in recombinant antigen-specific IFN-γ gene expression was detected in the vaccinated animals. At necropsy (38 weeks APV), our multicomponent subunit vaccine imparted a significant protection in terms of reduction of MAP burden in target organs as compared to sham-immunized goats. This study indicates that our multicomponent subunit vaccine induced a good Th1 response and conferred protection against MAP infection in a goat challenge model.

Modulatory influence of Adhatoda vasica Nees leaf extract against gamma irradiation in Swiss albino mice

The radiomodulatory influence of ethanolic extract of Adhatoda vasica Nees leaf extract against radiation-induced hematological alterations in peripheral blood of Swiss albino mice was studied at various post-irradiation intervals between 6 h to 30 days. Oral administration of A. vasica leaf extract (800 mg/kg body weight) prior to whole body irradiation showed a significant protection in terms of survival percentage and hematological parameters. Mice exposed to radiation (8.0 Gy) without A. vasica leaf extract pre-treatment exhibited signs of radiation sickness like anorexia, lethargicity, ruffled hairs and diarrhoea and such animals died within 25 days post-irradiation. The dose reduction factor (DRF = 1.6) for A. vasica leaf extract was calculated from LD50/30 values. A significant decline in hematological constituents (RBCs, WBCs, Hb and Hct) was evident till day 15 and no animal could survive beyond day 25. Conversely, animals pre-treated with A. vasica leaf extract showed 81.25% survival till 30 days after exposure and a gradual recovery was noted in the hematological values. However, these hematological values remained significantly below the normal even till day 30. A significant decrease in blood reduced glutathione (GSH) content and increase in lipid peroxidation (LPO) level was observed in control animals (Radiation alone). However, A. vasica leaf extract pretreated irradiated animals exhibited a significant increase in GSH content and decrease in LPO level. A significant increase in the serum alkaline phosphatase activity and decrease in acid phosphatase activity was observed in A. vasica leaf extract pretreated irradiated animals during the entire period of study.

Protective effects of brief intra- and delayed postischemic hypothermia in a transient focal ischemia model in the neonatal rat

Hypothermia provides neuroprotection in virtually all animal models of ischemia, including adult stroke models and the neonatal hypoxic–ischemic (HI) model. In these studies, brief periods of hypothermia are examined in a neonatal model employing transient focal ischemia in a 7-day-old rat pup. Pups underwent permanent middle cerebral artery (MCA) occlusion coupled with a temporary (1 h) occlusion of the ipsilateral common carotid artery (CCA). This study included five treatment groups: (1) normothermic (Normo)—brain temperature was maintained at 37 °C; (2) intraischemic hypothermia (IntraH)—28 °C during the 1-h ischemic period only; (3) postischemic hypothermia (PostH)—28 °C for the second hour of reperfusion only; (4) late-onset postischemic hypothermia (LPostH) cooled to 28 °C for the fifth and sixth hours of reperfusion only; and (5) Shams. After various times (3 days–6 weeks), the lesion was assessed using 2,3,5-triphenyltetrazolium chloride (TTC) or hematoxylin and eosin (H&E) stains. Intraischemic hypothermia resulted in significant protection in terms of survival, lesion size, and histology. Postischemic hypothermia was not effective in reducing lesion size early after ischemia, but significantly reduced the eventual long-term damage (2–6 weeks). Late-onset postischemic hypothermia did not reduce infarct volume. Therefore, both intraischemic and postischemic hypothermia provided neuroprotection in the neonatal rat, but with different effects on the degenerative time course. While there were no observable differences in simple behaviors or growth, all hypothermic conditions significantly reduced mortality rates. While the protection resulting from intraischemic hypothermia is similar to what is observed in other models, the degree of long-term ischemic protection observed after 1 h of postischemic hypothermia was remarkable and distinct from what has been observed in other adult or neonatal models.

Alteration of lethal effects of gamma rays in Swiss albino mice by Tinospora cordifolia.

Tinospora cordifolia is widely used in Ayurvedic medicines. It is known for its immunomodulatory, antihepatotoxic, antistress and antioxidant properties. It has been used in combination with other plant products to prepare a number of Ayurvedic preparations. The present study was undertaken to evaluate the radioprotective effect of an aqueous extract of Tinospora cordifolia (TC) against (60)Co gamma radiation. Oral administration of TC 5 mg/kg body wt to Swiss albino mice 1 h and 15 days prior to whole body radiation exposure (8 Gy) produced a significant protection in terms of survival percentage. After oral administration of TC 10 mg/kg body wt/day to mice 7 days prior to whole body irradiation (8 Gy) there was no mortality until day 13 and 50% of the animals survived until day 30. Mice exposed to radiation (8 Gy) without TC pretreatment exhibited signs of radiation sickness such as anorexia, lethargy, ruffled hair, diarrhoea and these animals died within 14 days of irradiation. The results from the present study suggest that Tinospora cordifolia has a radioprotective effect in Swiss albino mice, thereby enhancing the survival of mice against a sublethal dose of gamma radiation.

Potential role of the peroxynitrate-poly(ADP-ribose) synthetase pathway in a rat model of severe hemorrhagic shock.

Peroxynitrite (a potent oxidant produced by nitric oxide and superoxide) and hydroxyl radical, reactive oxidants produced during hemorrhagic shock, are potent triggers of DNA single-strand breakage. DNA injury triggers the activation of the nuclear enzyme poly(ADP-ribose) synthetase (PARS), which contributes to cellular injury. Hemorrhagic shock is associated with early vasomotor paralysis as well as with early derangements in the cellular metabolic status. Here we have tested whether activation of PARS contributes to the vasodilatation and early mortality in a rat model of severe hemorrhagic shock. In anesthetized rats hemorrhaged to a mean arterial blood pressure of 35 mmHg, pretreatment with the PARS inhibitor 5-iodo-6-amino-1,2-benzopyrone significantly improved survival rate. Furthermore, an inhibitor of nitric oxide biosynthesis (NG-methyl-L-arginine) and the cell-permeable superoxide dismutase mimetic Mn(III)tetrakis(4-benzoic acid) porphyrin also offered a significant protection in terms of hypotension and acute mortality. However, the selective inhibitor of the inducible nitric oxide synthase, mercaptoethylguanidine, failed to affect blood pressure or mortality. The present data suggest that PARS activation plays a role in the pathophysiology of hemorrhagic shock. Early production of peroxynitrite (produced by nitric oxide from constitutive nitric oxide synthase) and hydroxyl radical may induce DNA single-strand breakage, which is the immediate trigger of PARS activation.

Salmeterol provides prolonged protection against exercise-induced bronchoconstriction in a majority of subjects with mild, stable asthma

In patients with asthma, exercise-induced symptoms are well recognized and frequently limiting. Currently available β 2-receptor agonists have a short duration of action and breakthrough symptoms may occur. We studied the efficacy of the recently developed long acting inhaled β 2-agonist salmeterol with respect to protection against exercise-induced bronchoconstriction. Twelve patients with mild to moderate, stable asthma were recruited (age range 21–33 years). They each underwent treadmill exercise tests, with target heart rate of approximately 90% of predicted maximu, 1, 6 and 12 h after a single dose of salmeterol 50 μg, salbutamol 200 μg and placebo. Patients breathed through a two-way valve, inspiring dry air from a compressed air cylinder via a Douglas bag to maintain constant humidity. The primary efficacy variable analysed was the maximum percentage fall in FEV 1 and FVC from pre-exercise readings within the first 30 min post-exercise. At 1 h post-dose there was significant protection in terms of fall in mean ± sem FEV 1 in response to exercise challenge after either salmeterol (0·83 ± 6·2%) or salbutamol (3·8 ± 5·5%) as compared with placebo (27·1 ± 7·3%). At 6 h post-dose, fall in FEV 1 on salmeterol was 11·3 ± 3·8% as compared with salbutamol, 28·0 ± 5·7% and placebo, 32·0 ± 7·0%. At 12 h post-dosing there was still significant protection in terms of fall in FEV 1 in the salmeterol treated group, 12·8 ± 4·9%, as compared with salbutamol, 28·7 ± 4·9% and placebo, 25·4 ± 7·3%. Similar results were found with respect to changes in FVC in these patients. We conclude that salmeterol is effective in protecting against exercise-induced bronchoconstriction in the majority of subjects with mild, stable asthma and that this effect lasts for at least 12 h.

Characterization of Resistance and Immunity to Eimeria tenella Among Major Histocompatibility Complex B-F/B-G Recombinant Hosts

The relative influence of the B-F vs. B-G chromosomal regions on innate resistance and immunity to Eimeria tenella was studied among six B-F/B-G recombinants, designated BR1, BR3, BR4, BR5, BR6, and BR8. In one experiment, resistance was studied among 340 F1 chicks each carrying the B17 allele derived from Line UCD.003 and therefore also heterozygous for one of the B recombinant haplotypes. In a second experiment, acquired immunity was studied among 161F2 chicks each carrying one B17 allele and segregating for one of the recombinant alleles.In Experiment 1, F1 Chicks of similar haplotypes, BR3 and BR4 (BR3-G23) BR3, gained significantly more weight than those with BR1 (BF24-G23) and BR5 (BF21-G19) following exposure to a single high dose of 25,000 oocysts, although no differences in lesion scores were detected among the six recombinants. Following exposure to a single low dose of 2,500 oocysts, F1 chicks BR3 and BR4 also gained significantly more weight and had significantly lower lesion scores than BR1 or BR5 F1 chicks.To study acquired immunity in the F2 homozygous chicks, five consecutive daily exposures of 500 oocysts were followed 21 days later by challenge with 10,000 oocysts. The BR5 (BF21-G19) and BR6 (BF21-G23) homozygous chicks, both carrying the B-F21 allele, showed significant protection in terms of reduced lesion scores. These results demonstrate that E. tenella parasitism manifests itself to varying degrees in chicken hosts possessing different recombinant major histocompatibility complex haplotypes.

Modulation of the embryotoxicity in vitro of reactive metabolites of 2-acetylaminofluorene by reduced glutathione and ascorbate and via sulfation

To provide insights into mechanisms whereby reactive intermediary metabolites of foreign chemicals elicit teratogenic and embryotoxic effects, we initiated in vestigations of the capacity of physiologic factors to modulate the effects of embryotoxic metabolites of 2-acetylaminofluorene (AAF). The whole embryo culture system was utilized in order to avoid potentially confounding maternal factors. Reduced glutathione (GSH) effectively protected cultured embryos from the embryolethal effects of N-acetoxy-2-AAF (AAAF) and also reduced the severity of AAAF-elicited malformations although the percentage of embryos exhibiting malformations was not affected significantly. GSH also reduced the embryolethality of 2-nitrosofluorene (NF) as well as the percentage of NF-elicited axial rotation defects. Ascorbate protected against the embryolethality of both AAAF and NF and exhibited significant protection in terms of the capacity of NF to cause flexure abnormalities. However, significant protection against NF-elicited prosencephalic deformities was not detected. N-Acetylcysteine and α-tocopherol each failed to produce significant protection, even at the highest concentrations utilized. Enzymatic sulfation of N-hydroxy-AAF (N-OH-AAF) markedly increased the incidence of observable malformations. Synthesized N-sulfonyloxy-AAF also elicited a high incidence of malformations at relatively low concentrations when added to the culture medium. Malformations elicited, however, resembled those produced by NF rather than by AAAF. The results suggest than endogenous metabolic systems can play a critical role as determinants of both the quantitative and the qualitative capacity of foreign organic chemicals to produce embryotoxic or teratogenic effects via the generation of reactive intermediates.

Effect of bone marrow therapy on the volitional activity of whole-body x-irradiated rats.

Postirradiation injection of bone marrow suspension was used to test the hypothesis that the decrease in volitional activity seen during the 2nd and 3rd weeks after whole-body x-irradiation in the lethal range is related to damage of the hematopoietic system. The marrow preparation used was found to afford statistically significant protection in terms of lethality. Surviving irradiated animals treated with bone marrow suspension showed no decrease in activity during the 2nd and 3rd weeks postirradiation, even though the radiation dose used (650 r) was in excess of that required to produce such a decrease in the volitional activity of nontreated irradiated animals. Since the bone marrow treatment apparently affects hematopoiesis specifically, it appears that the volitional activity decrement during the 2nd and 3rd weeks after whole-body irradiation is related to hematopoietic damage. Further, it appears that a greater functional hematopoietic capacity is necessary to maintain normal volitional activity levels than is required to survive after x-irradiation.