Hydrogeochemical investigations and groundwater quality assessment of Torbat-Zaveh plain, Khorasan Razavi, Iran

Hydrogeochemical investigations of groundwater in Torbat-Zaveh plain have been carried out to assess the water quality for drinking and irrigation purposes. In this study, 190 groundwater samples were collected and analyzed for physicochemical parameters and major ion concentrations. The abundance of major cations and anions was in the following order: Na(+) > Mg(2+) > Ca(2+) > K(+), and Cl(-) > [Formula: see text] > [Formula: see text] > [Formula: see text]. As a result, alkaline element (Na(+)) exceeds alkaline earth elements (Mg(2+) and Ca(2+)), and strong acids (Cl(-) and [Formula: see text]) dominate weak acids ([Formula: see text] and [Formula: see text]) in majority of the groundwater samples. Statistical analyses including Spearman correlation coefficients and factor analysis display good correlation between physicochemical parameters (EC, TDS and TH) and Na(+), Mg(2+), Ca(2+), Cl(-) and [Formula: see text]. The results display that rock-weathering interactions and ion-exchange processes play important role in controlling groundwater chemistry. Saturation index values also indicate that water chemistry is significantly affected by carbonate minerals such as calcite, aragonite and dolomite. US Salinity Laboratory(USSL) and Wilcox diagrams together with permeability index values reveal that most of the groundwater samples are suitable for irrigation purpose. However, in some regions, the water samples do not indicate required irrigational quality.

Radioprotective effect of chicory seeds against genotoxicity induced by ionizing radiation in human normal lymphocytes

The search for less-toxic radioprotective agents has led to a growing trend towards natural products. Protective effect of the methanolic extract of chicory seeds (MCS) was investigated against genotoxicity induced by ionizing radiation in human lymphocytes. Human peripheral blood samples were collected and incubated with MCS at different concentrations (10, 50, 100, and 200 μg/mL) for two hours. The whole blood samples were exposed in vitro to X-ray at dose 2.5 Gy. Then, the lymphocytes were cultured with mitogenic stimulation to determine the micronucleus in cytokinesis blocked binucleated cell. The methanolic extract at all doses significantly reduced the frequency of micronuclei in binucleated lymphocytes, as compared with similarly irradiated lymphocytes without any extract treatment. The maximum protection was observed at 200 μg/mL of MCS, it completely protected genotoxicity induced by ionizing radiation in human lymphocytes. The extract exhibited a concentration-dependent radical scavenging activity on 1,1-diphenyl-2-picryl hydrazyl free radicals. HPLC analysis of MCS showed this extract is containing chlorogenic acid as a phenolic compound. These data suggest that the radioprotective effect of methanolic extract of chicory seeds can be attributed to the presence of phenolic compounds such as chlorogenic acid which act as antioxidant agents.

The effect of maternal hypothyroidism on cardiac function and tolerance to ischemia-reperfusion injury in offspring male and female rats

PURPOSE

Accumulating evidence indicates that intrauterine evolution disturbance can contribute to myocardial ischemia reperfusion (IR) injury; in addition, thyroid hormones (THs) have a crucial role in the development of different systems during fetal life. The aim of this study was to determine the effect of TH deficiency during fetal life on tolerance of isolated heart to ischemia during adulthood in both genders.

METHODS

Hypothyroidism was induced in pregnant Wistar rats by administrating 0.025 % 6-propyl-2-thiouracil in drinking water throughout pregnancy. Offspring of rats with maternal hypothyroidism (MH) and control groups were tested in adulthood. Isolated hearts were perfused with Langendorff setup and exposed to 30 min of ischemia, followed by 45 min of reperfusion. Baseline values of the left ventricular end-diastolic pressure (LVEDP), left ventricular developed pressure (LVDP), heart rate (HR), and peak rates of positive and negative changes in left ventricular pressure (±dp/dt) were recorded.

RESULTS

In the MH groups the baseline levels of LVDP (male: 23 %, female: 33 %), HR (male: 31 %, female: 26 %), and ±dp/dt were significantly (p < 0.01) lower, compared to controls. After ischemia, hearts from male rats with MH had less tolerance to IR injury as assessed in terms of reductions in recovery of hemodynamic parameters compared to controls, while in female rats there were no significant differences between MH and controls.

CONCLUSIONS

MH decreases hemodynamic parameters in the heart of both male and female offspring in adulthood; in addition, hearts of male rats with MH show less tolerance to ischemia, compared to those of females.

Photo neutron dose equivalent rate in 15 MV X-ray beam from a Siemens Primus Linac

Fast and thermal neutron fluence rates from a 15 MV X-ray beams of a Siemens Primus Linac were measured using bare and moderated BF₃ proportional counter inside the treatment room at different locations. Fluence rate values were converted to dose equivalent rate (DER) utilizing conversion factors of American Association of Physicist in Medicine's (AAPM) report number 19. For thermal neutrons, maximum and minimum DERs were 3.46 × 10^-6 (3 m from isocenter in +Y direction, 0 × 0 field size) and 8.36 × 10^-8 Sv/min (in maze, 40 × 40 field size), respectively. For fast neutrons, maximum DERs using 9” and 3” moderators were 1.6 × 10^-5 and 1.74 × 10^-5 Sv/min (2 m from isocenter in +Y direction, 0 × 0 field size), respectively. By changing the field size, the variation in thermal neutron DER was more than the fast neutron DER and the changes in fast neutron DER were not significant in the bunker except inside the radiation field. This study showed that at all points and distances, by decreasing field size of the beam, thermal and fast neutron DER increases and the number of thermal neutrons is more than fast neutrons.

In vitro protective effect of atorvastatin against ionizing radiation induced genotoxicity in human lymphocytes

Atorvastatin (AT) is widely used as a medication for treatment of hypercholesterolemia. Recent studies showed that AT enhanced cell toxicity induced by ionizing radiation in cancerous cells. In this study, the radioprotective effect of AT was investigated against genotoxicity induced by ionizing radiation in human blood lymphocytes. Peripheral blood samples were collected from human volunteers and incubated with AT at different concentrations (0.05, 0.1, 1, or 10 μM) for two hours. The whole blood was exposed to X-ray at dose 1.5 Gy. Lymphocytes were cultured with mitogenic stimulation to determine the micronuclei in cytokinesis blocked binucleated lymphocyte. AT exhibited a significant decreasing in the frequency of micronuclei in human lymphocytes exposed to ionizing radiation, as compared to with similarly irradiated lymphocytes without AT treatment. The maximum protection and higher decreasing in frequency of micronuclei was observed at 10 μM of AT (68% decrease), providing maximal protection against ionizing radiation. This data is promising for protection human normal cells from the genetic damage induced by ionizing irradiation.

The effect of thyroidectomy and propylthiouracil-induced hypothyroidism on insulin secretion in male rats

Data available on thyroid dysfunction and insulin secretion are inconsistent. The aim of this study was to assess the effect of hypothyroidism on insulin secretion, in vivo and in vitro, in rats. Adult Wistar male rats were divided into 4 groups, the control, the propylthiouracyl (PTU)-treated hypothyroid, the surgically thyroidectomized, and the sham-operated thyroidectomized. After 5 weeks, intravenous glucose tolerance test (IVGTT) was performed and 3 weeks later pancreatic islets were isolated to assess glucose induced insulin secretion and insulin content. Fasting serum glucose and insulin levels did not differ between the groups, but serum glucose concentration during IVGTT in the PTU-induced hypothyroid group was significantly higher as compared to controls, throughout 5-60 min. The serum glucose concentration during IVGTT in the thyroidectomized rats was also significantly higher than in the sham-operated ones, except at 10 and 60 min. The area under the curve of the serum insulin was significantly lower during IVGTT in the PTU-treated (10,010 ± 1,380 pmol/l/60 min) and thyroidectomized (13,930 ± 2,786) groups vs. their comparable groups (19,150 ± 2,110), p<0.01 and (20,650 ± 1,601), p<0.05, respectively. In the PTU-treated, but not in thyroidectomized animals, insulin secretion in response to glucose 8.3 and 16.7 mM was significantly lower than their comparable group. The results show that PTU- and thyroidectomy-induced hypothyroidism leads to impaired glucose tolerance due to reduced glucose stimulated insulin secretion. Islets insulin secretion is positively correlated with serum T3 and T4 concentrations.

Rapid antidepressant effects of repeated doses of ketamine compared with electroconvulsive therapy in hospitalized patients with major depressive disorder

Accumulating evidence suggests that N-methyl-d-aspartate receptor (NMDAR) antagonists (e.g. ketamine) may exert rapid antidepressant effects in MDD patients. In the present study, we evaluated the rapid antidepressant effects of ketamine compared with the electroconvulsive therapy (ECT) in hospitalized patients with MDD. In this blind, randomized study, 18 patients with DSM-IV MDD were divided into two groups which received either three intravenous infusions of ketamine hydrochloride (0.5 mg/kg over 45 min) or ECT on 3 test days (every 48 h). The primary outcome measure was the Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HDRS), which was used to rate overall depressive symptoms at baseline, 24 h after each treatment, 72 h and one week after the last (third) ketamine or ECT. Within 24 h, depressive symptoms significantly improved in subjects receiving the first dose of ketamine compared with ECT group. Compared to baseline level, this improvement remained significant throughout the study. Depressive symptoms after the second dose ketamine was also lower than the second ECT. This study showed that ketamine is as effective as ECT in improving depressive symptoms in MDD patients and have more rapid antidepressant effects compared with the ECT.

Is C771G polymorphism of MLX interacting protein-like (MLXIPL) gene a novel genetic risk factor for non-alcoholic fatty liver disease?

In a recent study, a genome-wide scan has identified C771G (His241Gln) polymorphism of MLX interacting protein like (MLXIPL) gene that is associated with the level of plasma triglycerides. Since, no study has been reported on the association between MLXIPL gene and non-alcoholic fatty liver disease (NAFLD), we aimed to identify a connection between this genetic variation and NAFLD. Two hundred and thirteen patients with NAFLD and 252 healthy controls were entered into this study. MLXIPL genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Our study showed that the single nucleotide polymorphism (SNP) of MLXIPL is significantly associated with NAFLD. Significant differences between cases and controls were observed for MLXIPL genotype frequencies (p<0.002). The frequency of C allele of MLXIPL in patient group was higher than the control group (68.30% vs. 51.59%, respectively; p<0.05). C771G polymorphism in the MLXIPL gene potentially plays a significant role in pathophysiology of non-alcoholic fatty liver disease. Further research is needed to confirm this finding.

Prevalence of transient hyperglycemia and diabetes mellitus in pediatric patients with acute leukemia

BACKGROUND

The most common malignancy of children is Leukemia, accounting approximately one third of cancer diagnosis. Available data demonstrate improvement in survival of pediatric leukemia, so evaluation of side effects of treatment is very important. This study investigates hyperglycemia and diabetes mellitus prevalence in pediatric patients with acute leukemia.

MATERIALS AND METHODS

This study was performed in children with acute leukemia. At the first admission, demographic data was collected and blood glucose and HbA1c levels were obtained. These tests examined at least two times during six months of follow up. Growth parameters and blood samples were obtained too.

RESULT

Twenty nine patients were examined; three of them (10.3%) had diabetes mellitus and 5patients (17.2%) had transient hyperglycemia.Mean age of the patients was 6.26 years and nineteen Children (63%) were in preschool age. In preschool age children, incidence of hyperglycemia was meaningfully higher than school age children (p= 0.02). 24 of 29 patients (82.7%) were known case of acute lymphoblastic leukemia (ALL) and 5 patients (17.3%) were known case of acute myeloblastic leukemia (AML). No significant difference was found between sex groups. Also underweight was significant risk factor for hyperglycemia.

CONCLUSION

The prevalence of hyperglycemia was in the range of other similar studies in different parts of the world. Underweight and preschool ages were significant predictors of hyperglycemia.

Side effects of hydroxyurea in patients with Thalassemia major and thalassemia intermedia and sickle cell anemia

BACKGROUND

Sickle hemoglobin is the most common abnormal hemoglobin in the United States. Hemoglobin S arises as a result of a single amino acid substitution (glutamic acid to valin at position 6 of the β-globine chain). The presence of fetal hemoglobin (HbF) plays a relatively protective role since a significant amount of HbF interferes with HbS polymerization, the pathogenesis mechanism of the vaso-occlusive symptoms that are the major contributor of the morbidity and mortality of this condition Thalassemia major and thalassemia intermedia have no specific molecular correlate but encompass a wide spectrum of clinical and laboratory abnormalities. Hydroxyurea (HU), an s-phase-specific and non-DNA-hypomethylating chemotherapeutic agents is capable of inducing HbF synthesis.

MATERIALS AND METHODS

This study was done on 56 patients, 28 patients with sickle cell anemia (SCA) and 28 patients with intermediate or major β-thalassemia. Start dose of HU was 10 mg/kg per day and increased by 5 mg/kg per day every 4-6 weeks until toxicity or according to clinical response.

RESULTS

The side effects were dermatologic in 39.28%, neurologic 23.2%, gastrointestinal 17.5% and hematologic 10.71% of patients. the statistical analysis didn't show significant relationship between variables such as history of blood transfusion, duration of HU treatment, age of start HU, age of diagnosis, dose of HU and ethnic with occurrence of HU adverse effects.

CONCLUSION

The HU therapy in our patients tolerated well and side effects were minor to moderate, benign and transient.

Effect of neonatal hypothyroidism on carbohydrate metabolism, insulin secretion, and pancreatic islets morphology of adult male offspring in rats

BACKGROUND

Neonatal hypothyroidism has serious effects on growth, development, and metabolism.

AIM

This study aims to investigate the effects of the neonatal hypothyroidism on carbohydrate metabolism, islet insulin secretion and morphology of the pancreatic islets in adult male offspring.

MATERIALS/SUBJECTS AND METHODS

Lactating mothers of Wistar rats consumed 0.02% solution of 6-propyl-2-thiouracil during the weaning period (neonatal hypothyroid group), while mothers of the control group drank merely tap water. Body weight and survival of pups were followed up. Intravenous glucose tolerance test was performed in adult male offspring and 5-6 weeks later, glucose-stimulated insulin secretion (GSIS) was evaluated.

RESULTS

During the glucose tolerance test, plasma glucose level of the neonatal hypothyroid group (13.18 ± 0.59 mmol/l) was significantly higher at 5 min compared to the control group (11.54 ± 0.47 mmol/l), whereas plasma insulin concentrations and GSIS of the groups was not significantly different. Homeostasis model assessment of insulin resistance of adult male offspring of the hypothyroid group (9.1 ± 1.0) was significantly higher as compared to the control group (4.5 ± 0.6). Area (14,613.0 ± 2646.3 μm2) and the diameter of the islets (147 ± 3.0 μm) of the neonatal hypothyroid group were significantly lower, as compared to the control group (32,886.3 ± 4690.3 and 206.6 ± 5.9 μm2 and μm, respectively).

CONCLUSION

Neonatal hypothyroidism can alter carbohydrate metabolism in euthyroid adult offspring, which may increase susceptibility to the development of glucose intolerance and occurrence of Type 2 diabetes later in life.

General anesthesia for lumbar puncture and bone marrow aspiration /biopsy in children with cancer

BACKGROUND

Multiple procedures (Lumbar puncture and bone marrow aspiration /biopsy) cause pain, stress, depression and etc for the patients and their families. Various methods have been recommended for pain reduction during invasive procedures. The aim of this study is to report the complications following general anesthesia.

MATERIALS AND METHODS

In this prospective observational study, two hundred and two children with cancer were enrolled. All patients received propofol 2.5 mg /kg and fentanyl 1 µg/kg. After adequate anesthesia, procedures were performed by a pediatric oncologist. All anesthesia complications were classified into two groups: Intraoperative and Postoperative complications. Complications which were recorded include: abnormal age-specific bradycardia (≤20 × baseline), decrease in arterial oxygen saturation (≤90%), laryngospasm, vomiting, agitation, headache, hypothermia (<35 C°), hyperthermia (>37/8 C°), signs of allergy, traumatic LP (bloody), and unusual local bleeding.

RESULTS

In this study, 118 males and 84 females underwent 623 general anesthetic procedures with a median of 3 procedures per patient. Intraoperative period complications occurred in 48 of total 623 procedures (7.7 %). The most common complications were traumatic LP, bradycardia and decrease in arterial oxygen saturation which occurred in 25, 6 and 6 cases, respectively. Postoperative period complications occurred in 74 (11.9%) cases. The most common complications were vomiting, agitation and headache, decrease O2 saturation and bradycardia.

CONCLUSION

General anesthesia by propofol and fentanyl may be a good choice for short-term painful procedures in children undergoing treatment for bone marrow aspiration/biopsy and intratechal injection.

Microtensile bond strength of self-etch adhesives in different surface conditionings

AIM

Self-etch bonding systems have been introduced recently and have the advantage of reduced operating time. Because of patient management and isolation difficulties in children, the present study aimed to evaluate microtensile bond strength of two self-etch bonding systems (AdheSE and Xeno® III) on cleaned only, ground and sandblasted enamel.

MATERIALS AND METHODS

Thirty intact primary molars were selected and randomly divided into two groups according to the type of bonding used (Xeno® III and AdheSE). The teeth were divided into three subgroups according to enamel surface conditioning method: prophylaxis with pumice, grinding with coarse finishing and polishing disc, and sandblasting with aluminum oxide particles. Tetric Ceram composite then was applied. Samples were sectioned coronally and axially. The interface area of dental sticks was measured and specimens were subjected to a tensile force of 0.5 mm/min until failure.

RESULTS

Microtensile bond strength of Xeno® III-sandblasting, AdheSE-sandblasting, AdheSE-grinding, and AdheSE- cleaned only were 25.5±7.7, 21.2±2.3, 12.9±2.2, and 9.1±1.1, respectively. During sectioning, all specimens of Xeno® III-cleaned only and Xeno® III-grinding groups were fractured.

CONCLUSIONS

Two step AdheSE yields higher mTBS in comparison to one step Xeno ® III. In regard to surface conditioning, sandblasting increases the mTBS relative to grinding with finishing and polishing disc, and the cleaned-only enamel has the lowest mTBS.

Effect of bonding application time on the microleakage of Class V sandwich restorations

BACKGROUND

The aim of this study was to assess the effect of bonding application time on the microleakage of Class V sandwich restorations.

METHODS

Eighty non-carious third molars were randomly divided into 16 groups. Two Class V cavities were prepared on the buccal and lingual surfaces of teeth. Three groups were restored with Fuji II GIC and treated with a total-etch bonding system (Stea/SDI) immediately after insertion, at 7 minutes and 15 minutes after mixing the glass ionomer cements (GICs). Another three groups were restored with Riva Self Cure GIC and treated with the total-etch system identically. The other six groups were subjected to self-etching bonding (Frog/SDI) after GIC placement in an identical procedure. The remaining groups were made using light cure GICs (Fuji II or Riva Light Cure) in conjunction with the total-etch or self-etching systems. Cavities were then restored with composite (Valux plus, 3M/ESPE). Samples were subsequently immersed in 2% methylene blue solution for 48 hours and observed under a stereomicroscope after sectioning. Four-scale grading was used to assess microleakage in occlusal and gingival walls. Data were analysed using Kruskal-Wallis and Mann-Whitney tests.

RESULTS

The self-etching bonding system exhibited more microleakage in occlusal margins regardless of time. Over time, microleakage significantly decreased in gingival margins in all self-cure groups except for Riva Self Cure treated with the total-etch system (p < 0.05).

CONCLUSIONS

Bonding application time had no effect on the microleakage of occlusal margins. However, maturation of GICs induced a decreased microleakage in gingival margins.

Association between serum nitric oxide metabolites and hypertension in a general population

AIM

Endothelial dysfunction and impaired release of endothelial nitric oxide occurs in hypertension. The aim of this study was to determine the relation between nitric oxide metabolites (NOx) concentrations and blood pressure levels in a general population.

METHODS

In a cross-sectional study, NO(x)was measured in 2,968 adult subjects, randomly selected from a population-based study, using the Griess method. Subjects were classified into normal, prehypertension, stage 1 hypertension and stage two hypertension groups, according to the seventh report of the Joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure.

RESULTS

Serum NO(x)values were negatively correlated with systolic blood pressure ≥160 mm Hg in men (r=-0.523, P=0.002). Serum NOx was higher in men with stage 1 hypertension while those with stage 2 hypertension had significantly lower NO(x) levels. In men, medication increased serum NO(x) concentration in both stages of hypertension but in women, a significant increase was observed only in stage 1 hypertension.

CONCLUSION

Serum NO(x) concentrations decreased in untreated stage 2 hypertension and increased in stage 1 hypertension in men, findings that suggest NOx measurement might be helpful for assessing endothelial (dys) function in male hypertensive subjects.

The role of 5-HT(3) receptors in the additive anticonvulsant effects of citalopram and morphine on pentylenetetrazole-induced clonic seizures in mice

Citalopram, a selective serotonin reuptake inhibitor (SSRI), is frequently used in the treatment of major depressive disorders. In addition to its antidepressant features, citalopram shows some anticonvulsive properties at lower doses, whereas higher doses, ingested in cases of suicide, have been associated with seizures. Moreover, some reports support the enhancing effect of morphine on different responses of SSRIs such as analgesic and anticonvulsant properties. Although the exact mechanisms of these additive effects are not yet fully understood, 5-HT(3) receptor has recently been shown to play an important role in the central effects of SSRIs and morphine. In this regard, we used a model of clonic seizures induced by pentylenetetrazole (PTZ) in male NMRI mice to investigate whether morphine and citalopram exhibit additive anticonvulsant effects and, if so, whether this effect is mediated through modulation of 5-HT(3) receptors. In our study, citalopram at lower doses (0.5 and 1 mg/kg, ip) significantly increased the seizure threshold (P<0.01) and at a higher dose (50 mg/kg) had proconvulsive effects. Moreover, morphine at low and noneffective doses had additive effects on the anticonvulsive properties of citalopram. This additive effect was prevented by pretreatment with low and noneffective doses of tropisetron (a 5-HT(3) receptor antagonist) and augmented by 1-(m-chlorophenyl)-biguanide (mCPBG, a 5-HT(3) receptor agonist). Moreover, low doses of morphine (0.1 and 0.5 mg/kg) alone or in combination with potent doses of 5-HT(3) receptor agonist or antagonist could not alter the proconvulsive properties of citalopram at higher dose (50 mg/kg), ruling out the contribution of 5-HT(3) to this effect. In summary, our findings demonstrate that 5-HT(3) receptor mediates the additive anticonvulsant properties of morphine and low-dose citalopram. This could constitute a new approach to augmenting the efficacy and curtailing the adverse effects of citalopram.

Sonographic measurement of uterus and ovaries in premenarcheal healthy girls between 6 and 13 years old: correlation with age and pubertal status

BACKGROUND

To provide normal references of sonographic uterine and ovarian size in premenarcheal healthy girls aged 6-13 years in different stages of puberty.

METHODS

Two hundred forty girls were enrolled into the study (mean age ± SD, 9.5 ± 1.7 years [range, 6-13.5 years]). Pubertal status was classified according to Tanner staging. All subjects underwent pelvic sonographic examination for the measurement of uterine volume, body and cervical length, anteroposterior diameter of fundus, body, and cervix, ovarian volume, and both right and left prominent follicular diameter.

RESULTS

A gradual increase with age was observed in all uterine and ovarian measurements. Both uterine and ovarian parameters were significantly correlated to age, height and weight, and stages of puberty. Uterine volume was <3.5 cm(3) in 98% of prepubertal girls, and in stage 2 it was significantly more than in stage 1 (3 ± 3.2 versus 1.7 ± 1.7, respectively) (p < 0.001). Uterine body length was also significantly greater in stage 2 than stage 1 (17.5 ± 4.5 versus 14.6 ± 3.3, respectively) (p < 0.001).

CONCLUSION

The reference values for uterus and ovaries were determined in healthy girls. There is a progressive increase in size of internal female genitalia in relation to age, height, weight, and puberty. Uterine volume and body length presented the best correlation with age and stage of puberty.

Hygroscopic expansion of aesthetic restorative materials: one-year report

OBJECTIVE

To measure the long-term linear hygroscopic expansion (LHE) of several materials using bulked and layered techniques.

MATERIALS AND METHODS

Seven materials were used; Fuji Cap II, Fuji II LC, Photac-Fil Aplicap, Vitremer, Dyract, Tetric and Z100. Ten specimens (6×4 mm) were made for each material using layered and bulked techniques (each group comprises five specimens). The specimens were stored in distilled water at 37°C. The length of each specimen was measured immediately after preparation, 24 hours, one week, one month, three months, six months, nine months and one year. This was used to calculate the percentage change in the length of materials. The mean LHE and standard deviation were calculated. Repeated measure analysis and paired sample t-test were used.

RESULTS

The type of material and time had a significant effect on LHE. Fuji Cap II and Fuji II LC exhibited no significant changes after one-year and one month, respectively. However, layered specimens of Photac-Fil Aplicap and Tetric showed constant expansion until six month, whereas bulked specimens reached the constant length at three months. Constant expansion was obtained for layered and bulked specimens of Dyract and Z100 at six month. Layered specimens of Vitremer showed no significant differences except between 24 hours and one year measurements. But in bulked specimens, the results at nine months and one year were significantly different from those obtained at three months and before.

CONCLUSION

Fuji II showed no significant LHE and resin-modified glass ionomer cements (RMGICs) exhibited the highest LHE. Dyract maintained an intermediate LHE in comparison with RMGIC and composite resin.

Administration of lithium and magnesium chloride inhibited tolerance to the anticonvulsant effect of morphine on pentylenetetrazole-induced seizures in mice

Although morphine has an anticonvulsant effect in several animal models of seizures, its potential clinical application in epilepsy may be hindered by its adverse effects like opioid tolerance. The present study evaluated the development of tolerance to the anticonvulsant effect of morphine in a model of clonic seizures induced with pentylenetetrazole (PTZ) in male Swiss mice. We also examined whether administration of either lithium chloride (LiCl) or magnesium chloride (MgCl(2)) was able to prevent the probable tolerance. Our data demonstrated that the anticonvulsant effect of a potent dose of morphine (1mg/kg) was abolished in chronic morphine-treated mice (mice administered the same dose of morphine intraperitoneally twice daily for 4 days). Four days of pretreatment with low and noneffective doses of MgCl(2) (2 and 5mg/kg) and LiCl (5mg/kg) inhibited the development of tolerance to the anticonvulsant effect of morphine (1mg/kg, ip). Moreover, a single acute injection of the aforementioned agents at the same doses reversed the expression of tolerance to the anticonvulsant effects of morphine (1mg/kg, ip). Chronic 17-day treatment with LiCl (600 mg/L in drinking water) also inhibited the development of tolerance to the anticonvulsant effects of 1mg/kg morphine. These results demonstrate that the anticonvulsant effect of morphine is subject to tolerance after repeated administration. Both development and expression of tolerance are inhibited by either LiCl or MgCl(2). As both LiCl and MgCl(2) can modulate the function of N-methyl-d-aspartate (NMDA) receptors, we discuss how NMDA receptor functioning might be involved in the effects of LiCl and MgCl(2) on the development of tolerance to the anticonvulsant effect of morphine.

The effect of maternal hypothyroidism on the carbohydrate metabolism and insulin secretion of isolated islets in adult male offspring of rats

Thyroid hormones have crucial developmental effect during fetal life. This study investigates the effects of maternal hypothyroidism on the carbohydrate metabolism and insulin secretion capacity of islets of the adult male offspring of rats. One group of pregnant mothers (fetal hypothyroid) of Wistar rats drank water containing 0.02% of 6-propyl-2-thiouracil during pregnancy, while the control group consumed only tap water. After delivery, survival and weight of the neonates from both groups were followed. In adult male offspring, the intravenous glucose tolerance test was performed and 5-6 weeks later, glucose-stimulated insulin secretion of isolated islets was assessed. Plasma glucose concentration of the fetal hypothyroid group during intravenous glucose tolerance test was significantly higher (p=0.003) at 5-20 min as compared to the control group, whereas plasma insulin concentration was significantly lower (p=0.012) at 5-20 min. Insulin secretion of the isolated islets stimulated with 16 mM glucose of the offspring in the fetal hypothyroid group (376.2 ± 57.1 pmol/islet/60 min) was significantly lower (p=0.02) as compared to the control group (618.1 ± 85.2). Although adult offspring born from hypothyroid mothers were euthyroid, their glucose tolerance and glucose stimulated insulin secretion of islets were altered, which may eventually contribute to the development of diabetes.