Effect of topical application of phenytoin and honey in closure of open wound in male rats

The aim of this study was to evaluate the effect of topical application of sodium phenytoin%1 ointment, Vaseline and honey on wound closure during inflammation, proliferation and remodeling phase. Experiments were carried out on 20 male rats weight 225 +/- 25 gr. Rats were anesthetized with ether, a circular wound with 2 cm diameter was performed on the back of neck. Rats were divided to four groups, one group dressed with sodium phenytoin%1 on the wound every other day, in the other group the wound was dressed with unbilled honey and the third group was dressed with Vaseline. In control group no dressing was done. Wound area measured in 3.7, 14 and 25 days after surgery and closure of wound were measured on 28ht. Data were analyzed by one way ANOVA. In 14th day size of wound in Vaseline group was significantly greater than control and phenytoin group, in 25th day there were no significant difference between the groups and%80 of honey and phenytoin groups and%60 in control group and%40 of in Vaseline were completely healed. In 28th day wounds healed in phenytoin, honey, control and Vaseline group 100%, 90%, 80% and 70% respectly. It seems that phenytoin effect is more effective in compare with honey in wound closure than honey. Applications of both of them accelerate wound closure

Effects of low level of lead exposure on blood pressure and responsiveness of the rat isolated heart to adrenergics

Exposure to low levels of lead increases blood pressure in humans and animals. Although there are controversial reports about the exact mechanisms of lead-induced hypertension, many factors such as alteration in the cardiovascular responsiveness to endogenous substances including catecholamines could be one of the mechanisms involved. In the present study, the effect of lead acetate on the systolic blood pressure and responsiveness to beta-adrenergics was investigated in rats. Through their drinking water, three groups of rats were exposed to 100 ppm lead acetate for periods of 4, 8 or 12 weeks. The blood pressures of the rats were monitored throughout the study. The rat hearts were isolated and perfused with Krebs-Henseleit solution [pH = 7.4] at 37°C and gassed with 95% O2 + 5% CO[2]. The heart rate [chronotropic] and contractile [inotropic] responses were recorded before and after adding isoproterenol at multiple concentrations to the perfusion solution. The mean blood pressures in the 8 and 12-week lead-treated groups were significantly higher than that of the control group [P < 0.01]. The chronotropic response to many doses of isoproterenol was significantly increased in the 12-week lead-treated group compared to that of the control group [P < 0.05]. The inotropic response to this drug was significantly increased in both the 8- and 12-week lead-treated rats [P < 0.05 and P < 0.01, respectively]. Our results indicate that low-levels of lead increase systolic blood pressure as well as both chronotropic and inotropic effects of beta-adrenergics, which could imply an important role in the pathogenesis of lead-induced hypertension

[Mechanism of paraoxon Effect on [[3]H] GABA uptake inhibition in brain synaptosomes of rat]

Parathion is an organophosphate compound that is frequently used as an insecticide. Paraoxon is the metabolic product of parathion which previously reported that inhibits GABA uptake by rat cerebral cortex synaptosomes. The aim of this study is to investigate possible underlying inhibitory mechanism[s] of paraoxon on GABA uptake, in synaptosomes prepared from rat cerebral cortex. After preparation of synaptosomes, kinetic studies were performed to determine the effect of paraoxon on K[m] and V[max] of GABA uptake. Acetylcholine and its antagonists [atropine and mecamylamine] were used to evaluate cholinergic dependency of GABA uptake. Type of GABA transporter involved was determined using beta-alanine and DAB A. The results of the study showed that paraoxon significantly decreased V[max] [175.2 +/- 4.23 vs. 80.4 +/- 2.03 pmol/mg protein/min, P<0.001] of GABA uptake while had no effect on its k[m] [9.80 +/- 1.02 vs. 9.09 +/- 0.92micro M in paraoxon and control groups respectively]. DABA significantly decreased GABA uptake [P<0.001] while beta-alanine had no effect. Acetylcholine had no effect on GABA uptake. On the other hand, neither atropine nor mecamylamine could reverse the inhibitory effect of paraoxon on GABA uptake. In conclusion, it seems that paraoxon acts as non-competitive anatagonist of GABA uptake, which affects kinetics of GABA uptake in nerve endings. We also conclude that the inhibitory effect of paraoxon on GABA uptake is cholinergic-independent

[Comparing deproteinization methods for serum nitric oxide assay by Greiss reaction]

Nitric oxide [NO] is involved in numerous physiologic and phathophysiologic processes. Recently, further investigators have focused on serum NO determination. In our previous study, we validated a simple, cheap and rapid method for serum NO determination based on the Greiss reaction. Deproteinization is a necessary step for this reaction, thus, the present study was designed to assess different deproteinization methods for serum NO determination. Ten common protein precipitating chemicals including methanol, ethanol, zinc sulfate, methanol/diethyl ether, acetonitrile, TCA, PCA, sodium tangstate, ammonium sulfate and filter were used for deproteinization of 42 human sera, while results were compared to filter separation as a reference. Serum NO levels were determined in 60 sera of adult human. Data showed that correlation coefficient of precipitating agents: methanol, ethanol, zinc sulfate, methanol-diethylether, acetonitrile, TCA, PCA, sodium tangstate, ammonium sulfate against filter separation method were 0.84, 0.92, 0.91, 0.79, 0.88, 0.85, 0.93, 0.53, and 0.78, respectively [p < 0.001]. Methanol, ethanol and methanol/diethylether caused overestimation, while TCA, PCA, sodium tangstate, and ammonium sulfate caused underestimation of serum NO results. Serum NO level had normal distribution with mean +/- SE of 33 +/- 1.3 micromol/L. Although different chemical protein precipitants are used for serum NO determination, our study revealed that zinc sulfate is the best choice for this purpose

[ preparation of rat cerebellar synaptosome and its applications in studying presynaptic membrane proteins]

Synaptosomes as an In Vitro model have unique properties. So, general method of preparation and their applications in studying presynaptic mebrane proteins are introduced. This study was done by using five rats and in every example. Synaptosomes were prepared from rat cerebellum. In order to verify structurally and functionally, biochemical, morphological and their response to depolarization were tested. Lactate dehydrogenize activity rised after exposure to detergent; 9 +/- 1.8 [n=5]. 15 mM K+-evoked depolarization increased synaptosomal exogenous neurotransmitter release 3 +/- 0.76 [n=5] times, compared to the basal state. Plasma membrane, mitochondrion and synaptic vesicles were observed in electron micrographs. Application of synaptosomal samples may provide useful information in both basic and clinical researches because it is efficient and can easily be prepared, even from human tissues

Evaluation of the HI-6 ability on reversal or prevention of paraoxon-induced changes in the function of Chichen Biventer cervices nerve-muscle preparation

Paralysis of skeletal muscles,which can lead to paralysis of respiratory muscles and death, is one of the most toxic effects of organophosphates [Ops],and oximes are almost the only known antidotes that can reverse or prevent such toxic effects. In the present research work, possible reversal or preventive effect of different concentrations of the relatively new oxime [HI-6] on paraoxon-induced changes on function of skeletal muscle of chicken biventer cervices [CBC] nerve- muscle preparation were studied using twitch tension recording technique. This is experimental study. For this purpose,twitches of the CBC muscle were evoked by stimulating the motor nerve at 0.1 Hz with pulses of 0.2 msec duration and a voltage of greater than that required to produce the maximum response. Twitches were recorded isotonically using Narco Biosystem. Our prior findings revealed that paraoxon at a concentration of 0.1 micro M induces a significant increase [more than 100%] in the twitch amplitude, and therefore, this concentration was used to examine the efficacy of HI-6 to reverse or prevent such effects. HI-6 at 1000 micro M could almost fully reverse [when it was used as post treatment] or prevent [when it was used as pretreatment or at the same time as toxin] the effect of paraoxon. It could also reverse or reduce this effect to about 25%, 50% and 75% at 300,100 and 30 micro M, respectively. Furthermore, HI-6 at 10 micro M produced no significant preventive or reversal effect. However, HI-6 alone at 1000 micro M increased the twitch amplitude by about 20%.These data indicated that HI-6 could be recognized as an antidote of paraoxon, although it may have other effects at high concentrations

[Evaluation of the HI-6 abillity on reversal or prevention of paraoxon-induced changes in the function of Chichen Biventer cervices nerve-muscle preparation]

Background: Paralaysis of skeletal muscles, which can lead to paralysis of respiratory muscles and death, is one of the most toxic effects of organophosphates [Ops], and oximes are almost the only known antidotes that can reverse or prevent such toxic effects. In the present research work, possible reversal or preventive effect of different concentrations of the relatively new oxime [Hl-6] on paraoxon-induced changes on function of skeletal muscle of chicken biventer cervices [CBC] nerve- muscle preparation were studied using twitch tension recording technique

Materials and methods: This is experimental study. For this purpose, twiches of the CBC muscle were evoked by stimulating the motor nerve at 0.1 Hz with pulses of 0.2 msec duration and a voltage of greater than that required to produce the maximum response. Twitches were recorded isotonically using Narco Biosystem

Results: Our prior findings revealed that paraoxon at a concentration of 0.1 micro M induces a significant increase [more than 100%] in the twitch amplitude, and therefore, this concentration was used to examine the efficacy of Hl-6 to reverse or prevent such effects. Hl-6 at 1000 micro M could almost fully reverse [when it was used as post treatment] or prevent [when it was used as pretreatment or at the same time as toxin] the effect of paraoxon. It could also reverse or reduce this effect to about 25%, 50% and 75% at 300,100 and 30 micro M, respectively. Furthermore, Hl-6 at 10 micro M produced no significant preventive or reversal effect. However, Hl-6 alone at 1000 micro M increased the twitch amplitude by about 20%

Conclusions: These data indicated that Hl-6 could be recognized as an antidote of paraoxon, although it may have other effects at high concentrations

Effect of carrageenan-induced inflammation on blood flow in the rabbit knee joint

Experiments were carried out on anesthetized adult New Zealand rabbits. Acute joint inflammation was achieved by intra-articular injection of 2% carrageenan. Radiolabelled microspheres were used to measure the effect of acute inflammation on blood flow in the knee joint and establish whether neural influences on blood vessel caliber were affected. Surgical exposure of the posterior joint "capsule" increased blood flow in the control knee, but subsequent section of the posterior articular nerve [PAN] supplying the knee produced no further increase. In the inflamed knee, blood flow declined progressively with each procedure. Electrical stimulation of PAN reduced blood flow in the posterior region of both knees, with somewhat less effects in the inflamed knee

Pre-and postjunctional alpha-adrenoceptors in rabbit articular blood vessels

Previous in vitro work on rabbit knee joint vessels showed that vasoconstrictor effects of nerve stimulation and administration of a-adrenoceptor agonists were mediated predominantly by alpha1-adrenoceptors. The present experiments were performed to assess the nature of alpha -adrenoceptor subtypes within these blood vessels in vivo. Dose/response relationships for adrenaline and noradrenaline produced a similar pattern of increasing constriction of articular vessels with increasing doses of drug. The alpha 1 agonist phenylephrine also produced dose-dependent constrictor responses which were diminished by prazosin. Using the alpha 2 agonists clonidine and UK -14304, responses in vivo differed from those previously observed in vitro. There was virtually no response to clonidine in vitro while responses were obvious in vivo. Although UK-14304 was found to have small effects in vitro, but only at high doses, this agent exerted more potent effects in vivo, significantly greater than those obtained with phenylephrine. Responses to the alpha 2 agonists were not altered significantly by prazosin but were reduced by rauwolscine. Following injection of UK-14304, the constrictor response to nerve stimulation was reduced. The results suggest that both alpha 1 and alpha 2 adrenoceptors are present postjunctionally within articular blood vessels, and also that prejunctional alpha 2 receptors are present which presumably regulate neurotransmitter release from sympathetic nerve endings in the joint capsule

Cardiovascular responses to hypercapnia and varying levels of arterial pH in the anesthetized cat

Effects of acute hypercapnia on the cardiovascular system [CVS] were studied in the anesthetized cat. After surgery the animal was exposed to a gas mixture of 12% CO2 and 25% o2 in nitrogen, and hypercapnia with low levels of arterial pH [pHa] was produced for 20 minutes. In the second run the same level of hypercapnia was induced by ventilating the same cat from the above gas mixture but pHa was kept normal by a slow and continuous infusion of THAM [0.5 mM/ kg/min]. Results of this study showed that hypercapnia increased aortic flow and induced peripheral vasodilation. Hypercapnia produced tachycardia in the presence of arterial acidosis whereas in its absence this response reversed to bradycardia. Hypercapnia increased mean arterial blood pressure [Pa] by 20% during low pHa, whereas this increase was only 10% in the absence of arterial acidosis. Therefore, it is concluded that hypercapnia in conjunction with arterial acidosis has a much stronger stimulatory influence on the CVS via different arterial chemoreceptors