Iranian Biomedical Journal
Volume:12 Issue: 4, Oct 2008

Olfactory ensheathing glia (OEG) has been shown to have a neuroprotective effect after being transplanted in rats with spinal cord injury. This study was conducted to determine the possible beneficial results of olfactory mucosa transplantation (OMT) which is a source of OEG on functional recovery and axonal regeneration after transection of the sciatic nerve. In this study, 36 adult female Sprague-Dawley rats were used. The sciatic nerve was transected in 24 rats and immediately repaired by sciatic-sciatic anastomosis, and randomly divided equally into two groups. The experimental group received the OMT at the transected site and the control group received the respiratory mucosa transplant. In another twelve rats as sham-operated animals, the sciatic nerve was exposed but no transection was made. DiI retrograde tracing was injected in the gastrocnemius muscle two months after surgery to allow visualization of the extent of axonal regeneration. Functional recovery was also assessed at 15, 30, 45 and 60 days after surgery using walking track analysis and sciatic function index (SFI) calculations. The total number of DiI labeled motorneurones in the ventral horn (L4-L6) and the SFI scores were significantly higher in the group of rats that received olfactory mucosa rather than respiratory mucosa. The outcome indicates that olfactory mucosa is a useful treatment to improve nerve regeneration in mammals with peripheral nerve injury

In this study, the effects of three structural analogues of adenosine upon proliferation of human tumor cells were investigated. Previous research showed a cytotoxic effect of adenosine via A3 receptor and A1 receptor and sometimes this effect was receptor independent. The researches showed a differential cytotoxic effect of adenosine and its A3 agonists on cancerous cells, while other studies demonstrated tumor promoting effect of adenosine and its A1 agonists. The purpose of the present study was the evaluation of the possible selective anti-tumor effect of A1 receptor agonists on cancerous cells. The substances of N6-cyclohexyl-adenosine (CHA, A1 agonist), R-isomer of N6-phenylisopropyladenosine (R-PIA, A1 agonist) and N5-ethylcarboxamido-adenosine (NECA, adenosine A1-A2 non-specific agonist) were tested for their anti-proliferative effect using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay method. Hep G2, Hep2, CACO2, ACHN and L929 cell lines were used in this assay. CHA inhibited cell proliferation in three cell lines (in concentration of 5-50 µM) and R-isomer of R-PIA in one cell line (in concentration of 10-50 µM). These effects were inhibited partially by addition of 1,3-Dipropyl-8-cyclopentylxanthine (A1 antagonist). The NECA analogue had no inhibitory effect on the cell proliferations. All of the substances had no cytotoxic effect on L929 cells (mouse connective tissue fibroblast cell line). CHA and R-PIA had inhibitory effect on the proliferation of human tumor cell lines partially via A1 receptor, while they didn''t show such effect on fibroblast cells. These results suggest that A1 adenosine receptor agonists have a good potential of specific anti-tumor activity

Mediodorsal (MD) thalamic nucleus, which is considered to take place between extra pyramidal and limbic feedback circuit, receives projective fibers from ventrolateral neurons of reticular part of substantia nigra (SNr). In order to better understand the influence and chemical reaction of these fibers upon MD nucleus, the morphology and synaptology of them were examined in the present study. Phaseolous vulgaris-leucoagglutin (PHA-L) was injected into substantia nigra pars reticulate. After 3-4 days, the sections of SNr injection site and MD nucleus were prepared. Then, we examined organization, morphology and, synaptology of PHA-L labeled SNr fibers that go to caudal and lateral part of MD thalamic nucleus. At the electron microscopic level, the SNr terminals made synapses predominantly with the medium to small dendrites and far less frequently with soma and large dendrites. These terminals were packed with polymorphic synaptic vesicles and formed symmetrical synapses; furthermore, it has been already recognized that cortico straital fibers from sensory-motor cortex go to region of the SNr that give rise to the nigrothalamic fibers. This data suggest that upon the synaptic organization, morphology and chemical nature of GABAergic, SNr fibers may have different inhibitory influence on MD neurons regulating the thalamic output from MD to cerebral cortex in the control of limbic and extra pyramidal feedback system

Free radical formation and oxidative stress might play an important role in the pathogenesis of Parkinson''s disease (PD). In vitro data indicate that neuromelanin (NM) pigment is formed the excess cytosolic catecholamine that is not accumulated into synaptic vesicles via the vesicular monoamine transporter 2 (VMAT2). We designed this study to investigate the neuroprotective effects of vitamin E in the early model of PD. Male rats (n = 40) with unbiased rotational behavior were randomly divided into five groups: sham operated group (SH, n = 8), vehicle-treated SH group (SH + V, n = 8), vitamin E-treated SH group (SH + E, n = 8), vehicle-treated lesion group (L + V, n = 8) and vitamin E-treated lesion group (L + E, n = 8). Unilateral intrastriatal 6-hydroxydopamine (12.5 µl) lesioned rats were treated intramuscularly with α-tocopherol acid succinate (24 I.U/kg, intramuscular [i.m.]) 1 h before surgery and three times per week for 2 month post-surgery. To evaluate the vitamin E pretreatment efficacy, tyrosine hydroxylase (TH) immunoreactivity and immunostaining intensity (ISI) for monoamine transporter 2 were used. TH immunohistochemical analyses showed a reduction of 20 percent in locus coeruleus (LC) cell number of vitamin E pretreated lesioned group but the cell number dropped to 60 percent in the lesioned group. The ISI of the cells was measured for VMAT2 in LC. Lesioned groups: 1) had the lowest VMAT2 ISI of all neurons; 2) There was an inverse relationship between VMAT2 ISI and NM pigment in the locus and 3) Neurons with the highest VMAT2 ISI also had high TH ISI. The data support the hypothesis that repeated i.m. administration of vitamin E exerts a protective effect on the LC neurons in the early model of PD

Vancomycin (glycopeptide)-resistant enterococci (VRE or GRE) can cause serious problems for hospitalized patients due to the limited options for treatment of VRE infections. As infection with VRE increases in hospitals, further knowledge about vancomycin resistant genes is needed. Isolates of Enterococcus spp. were collected from hospitalized patients in Tehran (Iran) during 2006. Detailed molecular analysis was performed for vancomycin resistance genotype and vanHAX using conventional PCR and PCR- RFLP (restriction fragment length polymorphism), respectively. out of 830 enterococci spp., 48 VRE isolates (5.8 percent) were obtained. All of VRE isolates carried vanA gene. DdeI digestion of vanHAX element showed the presence of point mutation at 8234 position. This study indicates that vanA is a predominant genotype in Iranian isolates. In addition, PCR-RFLP analysis revealed the presence of two types of vanHAX element in vanA harboring transposons

Aflatoxins are toxic fungal metabolites enable to contaminate a wide range of natural substrates. This contamination can be host-specific for different plant species. In this study, the ability of a toxigenic Aspergillus parasiticus to produce various aflatoxins on major Iranian cereals was evaluated with special focus on plant susceptibility to toxin production at cultivar level. Aspergillus parasiticus cultured on major Iranian cereal cultivars and some selected spices was incubated in shaking condition at 28ºC for 6 days. The concentration of aflatoxins B1 and total (B1, B2, G1 and G2) was measured by thin layer chromatography. The amounts of aflatoxin B1 produced on maize, wheat and rice cultivars were in the ranges of 1.0-33.9, 41.9-193.7, and 39.1-82.3 µg/g fungal weight, respectively. Interestingly, genetically modified Bacillus thuringiensis rice (GM rice) of Tarom Molaii cultivar examined for the first time in this study showed less susceptibility to aflatoxin production in comparison with its normal counterpart (P<0.05). The mean of aflatoxin production on maize cultivars was less than both wheat and rice cultivars that indicates considerable resistance of maize to aflatoxin compared with two other cereals. Unlike to Cuminum cyminum, both Helianthus annuus and Carum carvi seeds were highly resistant to aflatoxin production. These results indicate that inter- and intra-species differences exist in susceptibility of the major Iranian cereals as well as spices tested to A. parasiticus growth and aflatoxin production. Further studies are recommended to determine resistance markers of selected cultivars of Iranian cereals.

The nucleus raphe magnus (NRM) is involved in thermoregulatory processing. There is a correlation between changes in the firing rates of the cells in the NRM and the application of the peripheral thermal stimulus. we examined the effect of reversible inactivation and excitation of NRM on mechanisms involved in tail blood flow (TBF) regulation in hypothermia. Hypothermia was induced in Male Wistar rats and cannula was implanted above the NRM. To evaluate the effect of nucleus inactivation on TBF, the amount of TBF was measured by Laser Doppler in hypothermic rats, before and after lidocaine microinjection into NRM. TBF was also measured after glutamate microinjection to assess the effect of nucleus excitation in hypothermic rats. Results indicated that after dropping TBF by hypothermia, microinjection of lidocaine into NRM significantly decreased TBF from 54.43 -/+ 5.7 to 46.81 -/+ 3.4, whereas glutamate microinjection caused a significant increase from 44.194 -/+ 0.6 to 98 -/+ 10.0 These data suggest that NRM have thermoregulatory effect in response to hypothermia

Renal ischemia reperfusion (IR) injury has been a major source of concern during the past decades and angiotensin converting enzyme (ACE) inhibitors have been successfully used to prevent this injury. There have been some controversial reports about the involvement of KATP channels in the mechanism of action of ACE inhibitors. In this study, we examined the effect of KATP channel blocker (Glibenclamide) on preventive effect of captopril on renal IR injury. Male sprauge-dawley rats were pretreated with glibenclamide (1, 5 and 25 mg/kg) and/or captopril (5 mg/kg). They were anesthetized using ketamine (50 mg/kg) and xylazine (10 mg/kg). The left flank was incised and the left renal artery was clamped for 30 minutes. After that, the kidney was reperfused for 2 hours and then the animal was killed. The Right and left kidneys were removed and evaluated for microscopic damage. Captopril reduced renal IR injury while glibenclamide by itself caused no change. Glibenclamide did not change the preventive effect of captopril. It seems that the preventive effect of captopril is not directly mediated by KATP channels and further attention should be paid to other receptor-mediated angiotensin II effects.