Iranian Journal of Basic Medical Sciences
Year:2014 | Volume:17 | Issue:5|Papers Count:12

Objective (s): Painful diabetic neuropathy is associated with hyperexcitability and hyperactivity of spinal cord neurons. However, its underlying pathophysiological mechanisms have not been fully clarified. Induction of excitatory/inhibitory neurotransmission imbalance at the spinal cord seems to account for the abnormal neuronal activity in diabetes. Protective properties of neurosteroids have been demonstrated in numerous cellular and animal models of neurodegeneration.Materials and Methods: Here, the protective effects of allopregnanolone, a neurosteroid were investigated in an in vivo model of diabetic neuropathy. The tail-flick test was used to assess the nociceptive threshold. Diabetes was induced by injection of 50 mg/kg (IP) streptozotocin. Seven weeks after the induction of diabetes, the dorsal half of the lumbar spinal cord was assayed for the expression of γ2 subunit of GABAA receptor using semiquantitative RT-PCR.Results: The data shows that allopregnanolone (5 and 20 mg/kg) markedly ameliorated diabetes-induced thermal hyperalgesia and motor deficit. The weights of diabetic rats that received 5 and 20 mg/kg allopregnanolone did not significantly reduce during the time course of study. Furthermore, this neurosteroid could inhibit GABAA receptor down-regulation induced by diabetes in the rat spinal cord.Conclusion: The data revealed that allopregnanolone has preventive effects against hyperglycemic-induced neuropathic pain and motor deficit which are related to the inhibition of GABAA receptor down-regulation.

Objective (s): Biochemical markers are important for the timely diagnosis and follow-up of ischemic events. Most of the markers have been previously studied in the context of cardiac ischemia. However, research on markers of non-cardiac events has been insufficient. Therefore, we investigated the relationship between troponin and myoglobin which are commonly used markers of cardiac ischemia, in non-cardiac ischemia.Materials and Methods: Forty-eight rats were equally divided into six groups. Group I was the control group. Group II was the sham group and received a simple laparotomy. The superior mesenteric artery was clamped in groups III and IV in order to create mesenteric ischemia. The left femoral artery was clamped in groups V and VI in order to create peripheral ischemia. Intracardiac blood samples were taken from all groups (during the 3rd hour of ischemia in groups III and V and the 6th hour of ischemia in group IV and VI) and troponin T and myoglobin levels were measured.Results: Troponin and myoglobin levels were statistically similar in groups I and II. Moreover, increments were detected for troponin and myoglobin in ischemia groups according to group I and II. Furthermore, higher troponin Tlevels were detected after three hours of mesenteric ischemia and higher myoglobin values were observed after six hours of mesenteric ischemia (P<0.05).Conclusion: Troponin T and myoglobin are not specific for non-cardiac ischemia, and they may be useful for detecting other ischemic events.

Objective (s): Solid dispersion formulation is the most promising strategy to improve oral bioavailability of poorly water soluble drugs. The aim of this study was to compare the effect of polyvinylpyrrolidone K30 (PVP) and poloxamer-188 (PLX) as carrier in solid dispersion formulations of celecoxib (CLX).Materials and Methods: Solid dispersions of CLX:PVP or CLX:PLX were prepared at different ratios (2:1, 1:1, 1:2, 1:4, 1:6) by solvent evaporation and melting methods, respectively. The characterization of samples was performed using differential scanning calorimetery (DSC), X-Ray powder diffraction (XRPD) and Fourier transform infrared spectroscopy (FT-IR). The Gordon-Taylor equation was used to estimate the Tg of solid dispersion systems and the possibility of the interaction between CLX and PVP. Also, the dissolution rate of all samples was determined.Results: DSC and XRPD analyses confirmed the presence of amorphous state of drug in solid dispersion systems. FT-IR studies showed CLX could participate in hydrogen bonding with PVP whilst no specific interaction between CLX and PLX was observed. Both PVP and PLX enhanced the dissolution rate of drug in solid dispersion samples. The dissolution rate was dependent on the ratio of drug: carrier. Interestingly, the solid dispersion samples of PLX at 2:1 and 1:1 drug: carrier showed slower dissolution rate than pure CLX, whilst these results were not observed for PVP.Conclusion: The effect of PVP on dissolution rate enhancement was more pronounced compared to the other carrier. Having a higher Tg and more effect on dissolution rate, PVP could be considered as a more suitable carrier compared to PLX in solid dispersion formulation of CLX.

Objective (s): Glaucoma is the second leading cause of blindness and it is related to oxidative stress based on numerous studies. Glutathione S-transferases (GSTs) are members of multigenic family, which have important role in cells as an antioxidant. In the present study, we examined the polymorphism of GSTT1 and GSTM1 deletion genotypes (T0M1, T1M0, and T0M0) in 100 Glaucoma patients (41with primary open angle glaucoma (PCAG), and 59 with primary closed angle glaucoma (POAG)) compared to 100 healthy subjects.Materials and Methods: GSTM1and GSTT1 polymorphisms were determined by multiplex polymerase chain reaction.Results: GSTM1 and GSTT1 null deletions genotypes were determined in 22 (53.7%) and 7 (17.1%) patients with PCAG and 34 (34%) and 15 (15%) in healthy subjects. Comparison between patients and healthy subjects regarding GSTM1 and GSTT1 genotypes revealed increase of GSTM1 null deletions genotypes in patients with PCAG (P=0.03).Conclusion: It was concluded that the increased frequencies of GSTM1 null in patients with PCAG could be a risk factor for incidence of PCAG in the Iranian population.

Objective (s): In this research, zeolite X and zeolite Y were used as vehicle to prepare intestine targeted oral delivery systems of indomethacin and ibuprofen.Materials and Methods: A soaking procedure was implemented to encapsulate indomethacin or ibuprofen within synthetic zeolites. Gravimetric methods and IR spectra of prepared formulations were used to assess drug loading efficiencies into zeolite structures. Scanning Electron Microscopy (SEM) was also utilized to determine morphologies changes in synthetic zeolites after drug loading. At the next stage, dissolution studies were used to predict the in vivo performance of prepared formulations at HCl 0.1 N and PBS pH 6.5 as simulated gastric fluid (SGF) and simulated intestine fluid (SIF), respectively.Results: Drug loadings of prepared formulations was determined between 24-26% w/w. Dissolution tests at SGF were shown that zeolites could retain acidic model drugs in their porous structures and can be able to limit their release into the stomach. On the other hand, all prepared formulations completely released model drugs during 3 hr in simulated intestine fluid.Conclusion: Obtained results indicated zeolites could potentially be able to release indomethacin and ibuprofen in a sustained and controlled manner and reduced adverse effects commonly accompanying oral administrations of NSAIDs.

Objective (s): This study dealt with the wet agglomeration process in which a small quantity of binder liquid was added into a suspension of crystals, directly in the stirring vessel where the crystallization took place. The purpose of this investigation was evaluation of the effect of temperature on the agglomeration process in order to gain insight into the mechanism of the formation of the agglomerates.Materials and Methods: Carbamazepine was used as a model drug and water/ethanol and isopropyl acetate were used as crystallization system and binder liquid, respectively. The agglomeration of crystals was carried out at various temperatures and the agglomerates were characterized in terms of size, morphology, density and mechanical strength.Results: Evaluation of the agglomerates along the course of agglomeration shows that the properties of the particles change gradually but substantially. Higher temperature of the system during agglomeration process favors the formation of more regular agglomerates with mechanically stronger and denser structure; this can be explained by the promotion effect of temperature on the agglomeration process.Conclusion: With optimized wet agglomeration temperature, spherical, dense, and strong agglomerates can be obtained.

Objective (s): To the best of our knowledge, this is the first report on the contributions of GST genetic variants to the risk of diabetic retinopathy in an Iranian population. Therefore, the objective of this study was to determine whether sequence variation in glutathione S-transferase gene (GSTM1 and GSTT1) is associated with development of diabetic retinopathy in type 2 diabetes mellitus (T2DM) Iranian patients.Materials and Methods: A total of 605 subjects were investigated in this case-control study; Study groups consisted of 201 patients with diabetic retinopathy (DR), 203 subjects with no clinically significant signs of DR and a group of 201 cases of healthy volunteers with no clinical evidence of diabetes mellitus or any other diseases. The GSTM1 and GSTT1 were genotyped by multiplex-polymerase chain reaction (multiplex-PCR) analysis in all 404 T2DM patients and 201 healthy individuals served as control.Results: Increased odds ratio showed that GSTM1-null genotype had a moderately higher occurrence in T2DM patients (OR=1.43, 95% CI=1.01–2.04; P=0.03) than in healthy individuals. However, the frequency of GSTT1 genotype (OR=1.41; 95% CI=0.92-2.18; P=0.09) was not significantly different comparing both groups. Although, regression analysis in T2DM patients showed that GSTM1 and GSTT1 genotypes are not associated with T2DM retinopathy development.Conclusion: Our findings suggest that GSTM1 and GSTT1 genotypes might not be involved in the pathogenesis of type 2 diabetes mellitus retinopathy in the Southern Iranian population. However, further investigations are needed to confirm these results in other larger populations.

Objective (s): The aim of present research was to develop matrix-mini-tablets of lornoxicam filled in capsule for targeting early morning peak symptoms of rheumatoid arthritis.Materials and Methods: Matrix-mini-tablets of lornoxicam were prepared by direct compression method using microsomal enzyme dependent and pH-sensitive polymers which were further filled into an empty HPMC capsule. To assess the compatibility, FT-IR and DSC studies for pure drug, polymers and their physical mixture were performed. The formulated batches were subjected to physicochemical studies, estimation of drug content, in vitro drug release, drug release kinetics, and stability studies. Results: When FTIR and DSC studies were performed it was found that there was no interaction between lornoxicam and polymers which used. All the physicochemical properties of prepared matrix-mini-tablets were found to be in normal limits. The percentage of drug content was found to be 99.60±0.07%. Our optimized matrix mini-tablets-filled-capsule formulation F30 released lornoxicam after a lag time of 5.02±0.92 hr, 95.48±0.65 % at the end of 8 hr and 99.90±0.83 % at the end of 12 hr. Stability was also found for this formulation as per the guidelines of International Conference on Harmonisation of Technical Requirements of Pharmaceuticals for Human Use.Conclusion: A novel colon targeted delivery system of lornoxicam was successfully developed by filling matrix-mini-tablets into an empty HPMC capsule shell for targeting early morning peak symptoms of rheumatoid arthritis.

Objective (s): It has been reported that the mutation of the pre-core (PC) and basal-core promoter (BCP) may play an important role in the development of HBV-related hepatocellular carcinoma (HCC). In this study the PC and BCP mutations were investigated in chronic HBV patients.Materials and Methods: In this study, 120 chronic HBV patients from Golestan, Northeast of Iran who were not vaccinated against HBV, were recruited from the year 2008 to 2012. HBV-DNA extraction from plasma and PCR were performed and positive PCR products were subjected to automated sequencing.Results: One hundred out of 120 (83.3%) patients were HBeAg negative. Comparison of our nucleotide sequences with reference sequence showed high rate mutation in BCP and PC region (96.66%). Frame shift mutation was found in 78 (65%) of patients in BCP region, among them 8 (6.6%) patients showed mutation in PC region.Conclusion: Our results demonstrated high rate of mutations in BCP and PC regions among HBV chronic patients in Northeast of Iran.

Objective (s): blaCTX-M and blaPER are two genes that encode class A extended-spectrum b-lactamases (ESBLs) and can be responsible for therapeutic problems. This study was carried out to evaluate the molecular properties of these genes in clinical isolates of Enterobacteriaceae by polymerase chain reaction (PCR), restriction digestion and sequencing.Materials and Methods: During six months, starting from January 2012, one hundred clinical isolates of Enterobacteriaceae were collected from urinary samples. The ESBL-producing isolates were detected by phenotypic confirmation test. After plasmid extraction, blaPER and blaCTX-M genes were detected using PCR by specific primers. The blaCTX-M PCR products were digested with Taq1, and two of the blaCTX-M genes were sequenced.Results: Phenotypic tests showed that 27 (27%) isolates were ESBL producers with the highest frequency for Klebsiella pneumoniae (47.4%) and Escherichia coli (17.9%). Twenty six (26%) of Enterobacteriaceae isolates harbored the blaCTX-M gene, and none of them had blaPER. The restriction analysis of PCR products showed that all blaCTX-M amplified products had the same patterns. Both sequenced bacteria were CTX-M-15 type ESBL carriers.Conclusion: The results of this study showed the blaCTX-M-15 gene in Enterobacteriaceae isolates for the first time in Mashhad, Iran. High degrees of associated resistance to co-trimoxazole and gentamicin were found in ESBL producers. Therefore, an integrated and regular management of antibiotic prescription need to be trained in our society.

Objective (s): This study was designed to investigate the effect of Phaleria macrocarpa aqueous extract (PM) on spermatogenesis by observing the histological changes of testes in adult male rats.Materials and Methods: PM was prepared by boiling the dried slices of P. macrocarpa fruits followed by filtering, centrifugation and freeze-drying to obtain the powder form. Eighteen Sprague Dawley adult male rats were divided into three groups (six in each group), designated as treatment (240 mg/kg PM), negative control (distilled water) and positive control (4mg/kg testosterone) and administered via intragastric gavage for seven weeks. In the sixth week of supplementation period, each male rat was introduced to five female rats. Afterward, all rats were sacrificed and the testes were removed for histological studies.Results: PM significantly increased the number of cell and the thickness of seminiferous tubules of male rats (P<0.05). However, there was no significant effect on the volume and size of testes. The mean of spermatogonia cells numbers of PM groups differed significantly from the negative and positive groups (P<0.05).Conclusion: PM showed potential value as an attractive alternative for improving sexual strength by increasing the number of spermatogonia cell and the thickness of the seminiferous tubules. Perhaps, PM could be suggested to be one of the herbal remedies that can improve men fertility. The results may have some clinical implication in the management of infertility.

Objective (s): In recent years, there has been an increasing amount of study on early diagnosis of kidney injury through sensitive and specific biomarkers. We examined the practical applicability of the urinary levels of NAG (N-acetyl-b-D-glucosaminidase), AP (alkaline phosphatase), and LDH (lactate dehydrogenase) as renal dysfunction screening biomarkers in full and pre-term newborns treated with gentamicin.Materials and Methods: Fourteen pre-term and fifteen full-term newborns who received gentamicin for suspected infections were enrolled. Serum and urine specimens were obtained before the zero days and after gentamicin infusion on the 1st, 3rd, and 5th days of treatment.Results: In full-term newborns a significant increase in urinary NAG, LDH, AP after 5 days of gentamicin administration compared with control group was noted (P<0.05, P<0.001 and P<0.01; respectively).Conclusion: Our findings indicate that urinary enzymes may be useful in full-term newborns as a non-invasive method for evaluation of tubular function.