Effect of spiramycin and tulathromycin on abomasal emptying rate in milk-fed calves

Impaired abomasal motility is common in cattle with abomasal disorders. The macrolide erythromycin has been demonstrated to be an effective prokinetic agent in healthy calves and in adult cattle with abomasal volvulus or left displaced abomasum. We hypothesized that 2 structurally related macrolides, spiramycin and tulathromycin, would also be effective prokinetic agents in cattle. Six milk-fed, male, Holstein-Friesian calves were administered each of the following 4 treatments: spiramycin, 75 000 IU/kg BW, IM, this dose approximates 25 mg/kg BW, IM; tulathromycin, 2.5 mg/kg BW, SC; 2 mL of 0.9% NaCl (negative control); and erythromycin, 8.8 mg/kg BW, IM (positive control). Calves were fed 2 L of cow's milk containing acetaminophen (50 mg/kg body weight) 30 min after each treatment was administered and jugular venous blood samples were obtained periodically after the start of sucking. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration. Spiramycin, tulathromycin, and the positive control erythromycin increased abomasal emptying rate compared to the negative control. We conclude that the labeled antimicrobial dose of spiramycin and tulathromycin increases the abomasal emptying rate in healthy milk-fed calves. Additional studies investigating whether spiramycin and tulathromycin exert a prokinetic effect in adult cattle with abomasal hypomotility appear indicated.

Evaluation of Anticonvulsive Effect of Magnesium Oxide Nanoparticles in Comparison with Conventional MgO in Diabetic and Non-diabetic Male Mice

INTRODUCTION

Some studies showed that magnesium has anticonvulsive effect in some animal models. Despite of the availability of well-studied anticonvulsant drugs, this evaluation was not carried on new kind of magnesium supplement, magnesium oxide nanoparticles (nMgO). According to the association between magnesium and convulsion and high prevalence of seizure and epilepsy in diabetics, this study was designed to evaluate the effect of nMgO compared to conventional MgO (cMgO) on strychnine-induced convulsion model in diabetic and non-diabetic mice.

METHODS

Healthy male albino mice were divided into 10 groups. Diabetes mellitus was induced by streptozotocin in 5 groups. Conventional and nanoparticle MgO (5 and 10mg/kg) were administered to diabetic and non-diabetic mice, then strychnine were injected and onset of convulsions and time of death measured after strychnine administration.

RESULTS

There were no significant differences between normal and diabetic groups in onset of convulsions and time of death. Pretreatment of cMgO did not have anticonvulsant effect in strychnine-induced convulsion in normal and diabetic mice. But nMgO significantly changed convulsion onset and death time after strychnine administration in normal and diabetic status (p < 0.05).

DISCUSSION

According to our results, it seems that acute administration of nMgO may be important in prevention of convulsion and is more effective than its conventional form in showing anticonvulsive effect that probably is related to the physicochemical properties of nMgO, especially in diabetic subjects, a point that need further investigations.

Evaluation of analgesic and anti-inflammatory effect of nanoparticles of magnesium oxide in mice with and without ketamine

OBJECTIVES

According to importance and increasing application of nanoparticles and their toxicity, the identification effects of nanoparticles on physiological systems are essential. Some studies show magnesium has analgesic effect in some pain models but this evaluation was not carried on nano-magnesium oxide (MgO). Thus, present study was designed to evaluation effect of Mgo nanoparticles alone and in combination with ketamine on two pain and inflammation model in mice.

MATERIALS AND METHODS

At this study, adult male mice was used which had 29±3 gram weight. Formalin and acetic acid tests were carried. Acetic acid (1%) was intraperitoneally injected 0.3ml and the abdominal writhing was counted from 10 to 30 minutes after it. Formalin (2.5%) was injected 0.04 ml/mouse subcutaneously in plantar site of mice.  The time of licking was cumulatively measured 0-5 (acute phase) and 15-25 (chronic phase) minutes later. Control (negative control), ketamine (0.1 mg/kg), MgO nanoparticles (5 and 10 mg/kg), conventional MgO (5 and 10 mg/kg) and ketamine with conventional and nanoparticles MgO groups were studied in both tests.

RESULTS

Mean of writhing was significantly decreased by all drugs with comparison to control group (p = 0.0001). This decreasing was significant between conventional and nanoparticle MgO. The time of licking at both acute and chronic phases of formalin test was significantly decreased by all drugs with comparison to control group. However, this mean had significant difference with MgO nanoparticles.

CONCLUSIONS

It seems that the nano-MgO induces analgesic and anti-inflammatory effects through central and peripheral mechanisms at experimental formalin and acetic acid testes and potentiates effect of ketamine.

Purification and optimization of production conditions of a marine-derived antibiotic and ultra-structural study on the effect of this antibiotic against MRSA

OBJECTIVES

In this study we have attempted to partially purify, characterize and optimize the fermentation condition for the antimicrobial compound production with anti-MRSA (Methicillin Resistant Staphylococcus aureus) activity produced by Pseudoalteromonas piscicida PG-02 bacterium, isolated from the Persian Gulf, and finally understand the morphological changes in MRSA due to this antibiotic.

MATERIALS AND METHODS

Optimization process of antibacterial compound production was studied based on the sources of carbon and nitrogen, optimum temperature, optimum pH and optimum incubation time. The purification of intended antibiotic was done using TLC and also thermostability and enzymatic stability treatment was studied. Ultrastructural study on the effect of intended antibacterial compound on MRSA was done using a Transmission Electron Microscopy (TEM).

RESULTS

The optimized bioprocess conditions for the maximum production were at temperature 28 degrees C, pH 7, NaCI 0.5% (w/v), 96 hrs (incubation time), glucose and tryptone as carbon source and nitrogen source, respectively. The antibacterial component showed thermal sensitivity but it was sensitive to proteinase K, so this compound may have proteinaceous nature. The results of sonication revealed that this compound is accumulated in both intra- and extra-cellular locations. TEM pictures showed disorganization of cytoplasmic membrane upon the extract treatment comparing to control so, it can be said that this antibacterial compound can be considered as a bactericidal agent against MRSA.

CONCLUSION

On the basis of obtained results, this bacterium can be regarded as a valuable strain for discovery of new weapon as bactericidal agent in fighting against multi-drug resistant bacteria especially MRSA.

Comparison of the effect of vanadium and deferoxamine on acetaminophen toxicity in rats

Aim:

Acetaminophen (APAP) can change to toxic metabolites at high dose; if these metabolites are in high amounts, the body will be unable to neutralize them, and several tissues including liver will be damaged. In the present study, the effect of vanadium was compared with deferoxamine on hepatotoxicity and also kidney function during APAP administration in rats.

Material and Methods:

The study was done in 5 groups (5 rats in each group): group I to V, respectively, received normal saline, APAP, APAP + deferoxamine, APAP + vanadium, and vanadium. At the end of the study, blood was collected and serum was separated for laboratory tests. The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine, sodium, and potassium were determined. The liver of the rats were separated for tissue processing and light microscopic examination.

Results:

APAP significantly increased; ALT level and deferoxamine and vanadium prevented its elevation. Also, deferoxamine and vanadium prevented increase of AST by APAP. The change of factors, which are related to the kidney function, i.e., BUN, creatinine, sodium, and potassium were not considerable.

Conclusion:

Thus, it was observed that vanadium had better effect than deferoxamine in the prevention of hepatotoxicity induced by APAP.

Mutation of the histidin residue of the DRH motif in vasopressin V2 receptor expression and function

BACKGROUND AND THE PURPOSE OF THE STUDY

Vasopressin type 2 receptor (V2R), a G protein coupled receptor (GPCR), plays an important role in the regulation of renal antidiuretic function. The highly conserved DRH motif is essential for G protein signaling of V2R; however its role especially regarding the histidin residue is not fully understood..

METHODS

Site directed mutagenesis was performed with replacements of the histidin to isoleucine by using nested polymerase chain reaction. ELISA was performed for receptor expression assay and the adenylyl cyclase activity assay was performed for functional characterization of DRI mutation on V2R signaling.

RESULTS AND MAJOR CONCLUSION

The adenylyl cyclase activity assay in COS-7 cells showed no difference in the amount of cAMP production between the wild type and the mutant V2 receptors. The V2 receptor expression was not changed in the presence of this mutation using ELISA assay. These results suggest that the role of histidin residue is not critical in the V2 receptor function, however further mutagenesis studies are required to define the role of this motif in V2R function.

The potential application of plant essential oils as natural preservatives against Escherichia coli O157:H7

Investigation were carried out to compare the efficiency of three plant essential oils; Zataria multiflora, Carum carvi and Mentha piperita as natural food preservatives. The effect of these plant essential oils at concentrations of 0.0, 0.3, 0.6 and 1% was studied against inoculated Escherichia coli O157:H7 (10(5) cfu mL(-1)) in prepared commercial chicken soup stored at 8 and 35 degrees C over seven (168 h) and three (72 h) days, respectively by plate count technique on CT-SMAC agar. Zataria multiflora was the most effective essential oil against the bacterium in all concentrations, followed by Mentha piperita and Carum carvi. The maximum inhibitory effects of all essential oils were seen at 1% concentration. The inhibitory effects were affected by the incubation temperature as well as by the type and concentrations of essential oils. The 1% concentration of Mentha piperita and 0.6 and 1% concentrations of Zataria multiflora essential oil showed bacteriostatic effect on growth of Escherichia coli O157:H7 at 35 degrees C. Also 1% concentration of Carum carvi, 0.6 and 1% concentrations of Mentha piperita and 0.6% concentration of Zataria multiflora essential oil had bacteriostatic effect while 1% concentration of Zataria multiflora essential oil showed bactericidal effect on the bacteria during the incubation period at 8 degrees C. It is concluded that selected plant essential oils have promising inhibitory effects on Escherichia coli O157:H7 in chicken soup and could be considered as natural food preservatives. This is especially relevant at a time when there is an increasing interest in finding more natural alternatives to many existing preservatives.

Evaluation of metallothionein expression as a biomarker of mercury exposure in Scatophagus argus

The effect of mercury exposure to total Metallothionein (MT) response and bioaccumulation under control and acute mercury exposure were investigated in scats (Scatophagus argus). Scats were exposed to different mercury concentrations (10, 20 and 30 microg Hg L(-1)) for 24, 48 and 72 h. Total MT levels were determined by Enzyme-Linked Immunosorbent Assay (ELISA) method. Mercury contents were determined through cold Vapour atomic Absorption spectrometry. Induction of MT during exposure was tissue specific, displaying different response pattern in gill and liver. Mercury accumulated much stronger in liver than gill and the latter also showed lower MT level. MT biosynthesis in liver showed a significant increase after exposure to different mercury concentration during different times. This increase was significantly correlated with mercury bioaccumulation. In contrast, presence of different mercury concentration during different times did not significantly modify total MT except for 72 h exposure at 30 microg L(-1) in gills. The results suggest that this form of MT existing in S. argus was Hg-inducible and could be extended the as a biomarker of mercury pollution in ecosystems.

A comparison study of effects of Echinacea extract and levamisole on phenytoin-induced cleft palate in mice

There are many reports that the teratogenic effects of phenytoin, especially cleft palate can be decreased by stimulation of maternal immune system. Also, there is some evidence that Echinacea extract and levamisole are immunomodulator drugs. So, in this study, we compared the prophylactic effects of levamisole and Echinacea extract on teratogenic effects of phenytoin. This study was performed on 32 pregnant mice that were divided into four groups. The first group (control group) received normal saline intraperitoneally and the other groups (test groups) received phenytoin (65 mg/kg intraperitoneally) at 10th day of gestation. Levamisole and extract of Echinacea purpurea were administrated at dose of 10 and 360 mg/kg intraperitoneally, respectively, in along with and 12h later after phenytoin injection, in two groups. Fetuses were carried out in 19th day of gestation and after determination of weight and length; they were stained by Alizarin red-Alcian blue method. Cleft palate incidence was 16, 5.3, and 3.2% in fetuses of mice that received only phenytoin, phenytoin with levamisole, and phenytoin with Echinacea extract, respectively. Mean weight and length of fetuses of animals that received levamisole and Echinacea extract were significantly greater than those received only phenytoin. It is concluded that Echinacea can stimulate immune system more than levamisole and has better prophylactic effect on incidence of phenytoin-induced cleft palate, but it is not significant.