The effect of surface treatment with Er:YAG laser on shear bond strength of orthodontic brackets to fi ber-reinforced composite

Objectives: This study aimed to investigate the effect of surface treatment with Er:YAG laser on shear bond streng- th (SBS) of orthodontic brackets to fi ber-reinforced composite (FRC). Study Design: Ninety human premolars were randomly divided into six groups of 15. FRC bars were bonded to the teeth with a fl owable composite (FC) and then underwent following treatments. In group 1 no further treatment was performed. In group 2 the FRC surfaces were covered by FC. An Er:YAG laser was employed to treat FRCs in groups 3 ( 200 mJ/10 Hz) and 4 (300 mJ/15 Hz). The FRC strips in groups 5 and 6 were fi rst covered by FC and then irradiated with Er:YAG laser at 200 mJ/10 Hz (group 5) or 300 mJ/15 Hz (group 6). Stainless steel brackets were bonded to FRCs using a light-cure adhesive system. After 24 hours, the samples were tested for SBS and the adhesive remnant index (ARI) scores were determined. Results: There was a signifi cant difference in SBS among the study groups (P <0.001). Pairwise comparisons in- dicated that SBS was signifi cantly lower in group 1 compared to all other groups (p<0.05) except group 2. Bond strength in group 6 was signifi cantly greater than all the study groups (p<0.05) except group 5. No signifi cant di- fference was found in ARI scores among the groups. Conclusions: Covering the FRC surface by a layer of fl owable composite and then application of Er:YAG laser at 300 mJ/15 Hz could be recommended to increase bond strength of orthodontic attachments to FRC

The effects of metformin on stereological and ultrastructural features of the ovary in streptozotocin-induced diabetes adult rats: An experimental study

Background: Diabetes is a chronic disease that can affect almost all of the body organs, including male and female reproductive systems. Objective: This study was designed to investigate the preventive effects of metformin on stereological and ultrastructure characteristics of the ovary in the streptozotocin-induced diabetes adult female rats. Materials and Methods: Seventy adult (8-10 wk) female Sprague-Dawley rats (180-200 gr) were equally divided, as follows: (n = 10/each) control; STZ-induced diabetes (single dose of 65 mg/kg STZ, IP); metformin-treated (50 mg/100 gr of body weight, orally); diabetic-metformin-treated; sham 1, (single dose of sodium citrate); sham 2, (0.5 ml of daily oral distilled water); and sham 3, (sodium citrate + distilled water treated). The body mass index, ovarian weight, blood sugar level, cholesterol, and triglyceride were measured. The stereological and ultrastructural features of ovary were assessed. Results: The blood sugar of induced-diabetic rats was increased (p &lt; 0.01). The BMI (p &lt; 0.01), number of granulosa cells (p = 0.04), primordial, primary and secondary follicles (p = 0.03), total volume of ovary (p &lt; 0.01) and cortex, nucleus diameter ratio to the ooplasm were decreased. The number of atretic follicles in the diabetic and diabetic + metformin-treated rats were increased (p &lt; 0.01). The ultrastructural characteristics of ovary were more damaged in diabetic rats. Conclusion: Diabetes has destructive effects on ovarian follicles and causes follicular atresia. Also, the size of oocytes, numbers of granulosa cells and ooplasmic organelles, which are involved in the folliculogenesis are affected by diabetes and metformin has no preventive effects. Key words: Diabetes, Metformin, Ovary, Tissue

The Influence of Exposure to Stress of Pregnant Rats on the Adrenal Gland Structure of their Offspring. An Unbiased Stereological Study

Many factors may interact with normal differentiation and growth of tissues and cells. Stress might be  experienced during pregnancy and it has been shown that stress may cause low birth weight. The effect of  prenatal manipulations on the HPA axis has been focused on physiological and biochemical alteration of  the adrenal gland. A stereological examination of the influences of prenatal stress on the structure of the  developing adrenal gland of one day and 21 day-old rats has now been performed. In this study experiments were conducted to test the hypothesis that exposure to restraint stress during pregnancy  in rat results in structural changes in the developing adrenal gland of their pups. Female rats were exposed to restraint stress from the first day of pregnancy throughout gestation. Male offspring  of stressed rats (PS= experimental) and of unstressed mothers (C= control) who were one day and 21  days of age were selected. Their body weight (BW), crown-rump length (CRL), biparietal diameter (BPD),  volume of the gland and the cortical layers and medulla were estimated using stereological methods. The results showed that the prenatal stress led to a decrease in BW, but CRL and BPD remained unchanged.  Also, a significant increase in volume of the adrenal gland and cortical layers in one day and 21 day-old  offspring were observed. The volume of the medulla of the adrenal gland of neonate rats remained  unchanged but the volume of the medulla in 21 day-old rats was decreased. Therefore, it can be concluded that prenatal stress alters the structure of the developing adrenal gland.

Association study of ESR1 rs9340799, rs2234693, and MMP2 rs243865 variants in Iranian women with premature ovarian insufficiency: A case-control study

Background: Primary ovarian insufficiency (POI) is a rare disease clinically characterized by ovarian follicles depletion or dysfunction and menopause before the age of 40 yr as the cut-off age for POI. It is a complex disease, and its etiology involves several factors. However, genetic factors have a predominant role in the susceptibility to the disease. Objective: This study aims to investigate the polymorphisms of rs243865 in the matrix metallopeptidase 2 (MMP2) gene and rs2234693 and rs9340799 in the estrogen receptor 1 (ESR1) gene with susceptibility to POI in Iranian women under 35 yr. Materials and Methods: This case-control study was performed on 150 women with POI and 150 healthy women who were referred to Yazd Reproductive Sciences Institute, Yazd, Iran between May-October 2020. The genotyping of ESR1 rs9340799, rs2234693, and MMP2 rs243865 polymorphism was done using tetra-amplification refractory mutation system-polymerase chain reaction. In addition, haplotype analysis and linkage disequilibrium were investigated by SNPanalyzer software. Results: Our study revealed the frequency of rs243865 TT, CC genotypes in the MMP2 gene and rs2234693 CC, TT; and rs9340799 GG, AA in the ESR1 gene were more prevalent in the case group compared to the control group. In addition, ESR1 rs2234693 and rs9340799 genotypes showed significant association with the development of the disease in our population. Among 4 haplotypes for 2 polymorphisms in the ESR1 gene, rs2234693T/rs9340799A haplotype was associated with conferring risk to POI. Conclusion: ESR1 rs2234693 and rs9340799 polymorphism were strongly associated with our population’s POI. Key words: Matrix metalloproteinase-2, Estrogen receptor alpha, Primary ovarian insufficiency, Female infertility

Automated Brain Tumor Segmentation on Multi-MR Sequences to Determine the Most Efficient Sequence using a Deep Learning Method

Brain tumor segmentation is an important step in the diagnosis and treatment planning of cancer patients. The procedure of manual brain tumor segmentation suffers from a long processing time. In this light, automatic brain tumor segmentation is highly appealing in the clinical routine. This study sets out to segment the tumors from brain MR images and to investigate the effectiveness/usefulness of the different MRI sequences for this purpose. Here, the MR images from the BRATS challenge were utilized. 310 patients with four different MRI sequences, including T1, T1ce, T2, and FLAIR were employed to train a ResNet deep CNN. Four separate models were trained with each of the input MR sequences to identify the best sequence for brain tumor segmentation. To assess the performance of these models, 60 patients (external dataset) were quantitatively evaluated. The quantitative results indicated that the FLAIR sequence is more reliable for automatic brain tumor segmentation than other sequences with an accuracy of 0.77±0.10 in terms of Dice compared to Dice indices of 0.73±0.12, 0.73±0.15, and 0.62±0.17 obtained from T1, T2, and T1ce sequences, respectively. Based on the results of this study, FLAIR is a more reliable sequence than other sequences for brain tumor segmentation

The Effects of Sex Hormones on Liver Regeneration after Liver Trauma in Animal Model

Background: The surgical management of liver injuries remains a great challenge for the traumatologists and general surgeons. We hypothesized that administration of 17 â-estradiol, a female sex hormone, improves&nbsp;hepatocellular healing after liver trauma.Methods: In an experimental model, 60 rats were divided into six subgroups: A (male control), B (male and estradiol), C (castrated male and estradiol), D (female control), F (female and estradiol), and G&nbsp;(oopherectomized female). After inducing liver trauma, estradiol subgroups received 3 doses of intravenous 17 â-estradiol (1 mg/kg) every 8 hours. 2 weeks post trauma, animals were sacrificed and hepatocellular regeneration was measured with the help of stereologic parameters of regeneration. Hepatocellular healing was compared between previous left lobe samples and the new post-traumatic right lobe samples.Results: Stereological parameters of rats receiving 17 b-estradiol after trauma was much better regarding mean angiogenesis point counting and volume density, compared with non-receiver groups after 2 weeks of trauma (P &lt; 0.005). There was no significant difference for hepatocyte nucleus, hepatocyte point counting and volume density between estradiol receiver and non-receiver groups. In a comparison between subgroups, female sex had the same effect as giving estradiol. Oopherectomized female rats had more fibrogenesis but less angiogenesis (P &lt; 0.005). Fibrogenesis was more in groups that were estradiol non-receiver (P &lt; 0.005). In an explicit comparison of control females and males, estradiol infused males and females, and castrated male or oopherectomized female groups showed that stereological parameters of hepatocyte and hepatocyte nucleus were lower in female subgroups, but angiogenesis was better for female groups except for oopherectomized females.Conclusions: This study did support the administration of exogenic female hormone as an approach to augment the angiogenesis as a good index of regeneration for traumatic liver in rats

An Experimental Investigation of Ultraweak Photon Emission from Adult Murine Neural Stem Cells

Neurons like other living cells may have ultraweak photon emission (UPE) during neuronal activity. This study is aimed to evaluate UPE from neural stem cells (NSC) during their serial passaging and differentiation. We also investigate whether the addition of silver nanoparticles (AgNPs) or enhancement of UPE (by AgNPs or mirror) affect the differentiation of NSC. In our method, neural stem and progenitor cells of subventricular zone (SVZ) are isolated and expanded using the neurosphere assay. The obtained dissociated cells allocated and cultivated into three groups: groups: I: cell (control), II: cell + mirror, and III: cell + AgNPs. After seven days, the primary neurospheres were counted and their mean number was obtained. Serial passages continuous up to sixth passages in the control group. Differentiation capacity of the resulting neurospheres were evaluated in vitro by immunocytochemistry techniques. Measurement of UPE was carried out by photomultiplier tube (PMT) in the following steps: at the end of primary culture, six serial cell passages of the control group, before and after of the differentiation for 5 minutes. The results show that neither mirror nor AgNPs affect on the neurosphere number. The UPE of the NSC in the sixth subculturing passage was significantly higher than in the primary passage (P < 0.05). AgNPs significantly increased the UPE of the NSC compared to the control group before and after the differentiation (P < 0.05). Also, the treatment with AgNPs increased 44% neuronal differentiation of the harvested NSCs. UPE of NSC after the differentiation was significantly lower than that before the differentiation in each groups, which is in appropriate to the cell numbers (P < 0.0001). The mirror did not significantly increase UPE, neither before nor after the differentiation of NSC. As a conclusion, NSC have UPE-properties and the intensity is increased by serial passaging that are significant in the sixth passage. The AgNPs increases the UPE intensity of NSC that pushes more differentiation of NSC to the neurons. The mirror was not effective in enhancement of UPE. As a result, UPE measurement may be suitable for assessing and studying the effects of nanoparticles in living cells and neurons.This work was supported by grant No. 94-01-01-10157 from Shiraz University of Medical Sciences, Shiraz, Iran. This article was a part of the thesis written by Esmaeil Fereydoni, MSc. student of Anatomy

The Relationship between Body Fat Distribution and Postmenopausal and Menopausal Women’s Quality of Life

Introduction: Considering the issue in the population of postmenopausal women, no study has been conducted in Iran so far on the relationship between body fat distribution and quality of life. This study aimed to investigate the correlation between body fat distribution and quality of life in menopausal women.Methods: The present descriptive study was conducted on 250 premenopausal and menopausal women aged 40-65 years. Samples were selected by a multi-stage random sampling method. Data were collected through a two-part questionnaire including demographic variables and a questionnaire on the postmenopausal women’s life quality in health centers. The data were analyzed using Statistical tests, distribution, frequency percentage mean score, Standard deviation, and independent sample t-tests.Results: The mean age of participants was 55.17 years. There was a statistically significant difference between the two forms of body fat distribution in the vasomotor domain (p = 0.021), the physical domain (p = 0.044), and the sexual domain (p = 0.001), but no statistically significant difference was observed for the psychological domain (p = 0.148).Conclusion: The results of the present study showed a significant difference in some aspects of the postmenopausal women’s life quality with pear-shaped and gynoid fat distribution

Effects of the Hydroalcoholic Extract of the Psidium guajava Fruit on Osteoporosis Prevention in Ovariectomized Rats

Background: Several plants have been shown to possess antioxidant and estrogenic properties that can be useful in postmenopausal bone-loss prevention. The present study aimed to investigate the anti-osteoporotic effects of the hydroalcoholic extract of the Psidium guajava (PG) fruit in ovariectomized (OVX) rats. Methods: Sixty female Sprague–Dawley rats were randomly divided into 6 groups: a control positive group, a sham-operated group, an OVX group given normal saline (OVX-only group), and 3 treatment groups comprising 2 OVX groups treated orally with 500 and 1000 mg/kg/d of the hydroalcoholic extract of the PG fruit respectively and an OVX group treated with an injection of 0.15 mg/kg of estradiol. The study was conducted over a 12-week period. Samples from the animals’ blood, femoral bones, and uteri were collected for stereological and biochemical analyses. The data were analyzed using SPSS, version 19. A P value equal to or less than 0.05 was considered statistically significant. Results: The results revealed a significant decrease in the levels of calcium, total antioxidant capacity, and phosphorus as well as uterus weight, femoral ash density, femoral volume and weight, and numbers of osteocytes and osteoblasts. Moreover, there was an increase in the levels of alkaline phosphatase and urine deoxypyridinoline together with a rise in the number of osteoclasts in the OVX-only group compared to the control and treatment groups (P≤0.05). The hydroalcoholic extract of the PG fruit increased femoral weight and volume, femoral ash density, numbers of osteocytes and osteoblasts, and trabecular volume of the bones in comparison with the OVX-only group in a dose-dependent manner. No significant difference was observed between the groups in the levels of malondialdehyde and interleukin-6. Conclusion: The hydroalcoholic extract of the PG fruit prevented OVX-induced bone loss in the rats, with no proliferative effect on atrophic uteri; it should, therefore, be considered for treatment purposes