جستجوی مقالات مرتبط با کلیدواژه "animal experiment" در نشریات گروه "پزشکی"
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Background
Obstructive nephropathy is a common clinical disease.
ObjectivesTo explore the value of diffusion tensor imaging (DTI) in obstructive nephropathy.
Materials and MethodsForty healthy Sprague-Dawley (SD) rats were examined in this study. Thirty-two animals underwent complete obstruction of the left ureter, while eight animals underwent a sham surgery. Magnetic resonance imaging (MRI) was performed before surgery and within different intervals after surgery. Eight rats from the experimental group and two rats from the sham group were used in each interval. Following MRI, the animals were sacrificed and sent for medical examinations. The scanning sequences included positioning, transverse T2-weighted (T2W), coronal, and coronal DTI sequences. Image postprocessing was performed after DTI to measure DTI parameters, including apparent diffusion coefficient (ADC) and fractional anisotropy (FA), and to reconstruct DTI fiber traces. One-way analysis of variance was used to compare the parameters between the cortex and medulla and between different intervals.
ResultsThe fiber tracing showed that the obstructed renal fiber bundles were sparse and disordered. The ADC and FA values of the renal cortex, extrarenal medulla, and inner medulla decreased with prolonged hydrops and were negatively correlated with the expression of alpha-smooth muscle actin (α-SMA) and the renal tubulointerstitial lesion grade (r < 0, P < 0.001). Comparison of the cortex, extrarenal medulla, and inner medulla showed the following trends for the ADC and FA values: cortex > extrarenal medulla > inner medulla and cortex < extrarenal medulla < inner medulla, respectively.
ConclusionsDTI in obstructive nephropathy not only can reflect the degree of renal interstitial fibrosis and accurately indicate the renal function, but also can provide information regarding renal blood perfusion, water metabolism, and ultrastructural changes.
Keywords: Animal Experiment, Diffusion Tensor Imaging, Obstructive Nephropathy -
زمینه و هدف
بازسازی ضایعات استخوانی از اهداف ایده آل درمان های پریو دنتال و ایمپلنت های دندانی می باشد. بیومتریال های مختلفی به منظور دستیابی به این هدف استفاده شده و مطالعات زیادی سعی در مقایسه و معرفی بهترین آن ها داشته است. هدف مطالعه حاضر بررسی اثر پیوند استخوانی منجمد خشک نسبتا دمینرالیزه (PDFDB) و آلوگرفت استخوانی خشک منجمد (FDBA) بر رژنراسیون دیفکت های استخوانی کالواریای خرگوش بود.
روش بررسیدر این مطالعه تجربی، 48 دیفکت مشابه با قطر 8 میلی متر در کالواریای 16 خرگوش ایجاد شد. دو دیفکت با FDBA و PDFDB پر شدند و دیگری به عنوان گروه کنترل خالی باقی ماند. کلیه دیفکت ها با ممبران کلاژنی پوشانده شدند. 6 هفته و 12 هفته بعد از جراحی، ارزیابی های هیستولوژیک و هیستومورفومتریک انجام شد تا این متغیرها ارزیابی شوند: میزان تشکیل استخوان جدید و نوع آن، میزان ماده پیوندی باقیمانده، درجه التهاب و الگوی تشکیل استخوان. مقایسه درصد استخوان سازی و بیومتریال باقی مانده با آزمون آنالیز واریانس تکراری انجام شد، در حالی که مقایسه متغیرهای کیفی توسط آزمون غیر پارامتری Friedman صورت گرفت.
یافته هابه لحاظ میزان تشکیل استخوان جدید، تفاوت معنی دار قابل توجهی بین سه گروه مطالعه در گروه 6 هفته ای (33/0=P) و در گروه 12 هفته ای (98/0=P) دیده نشد. در نمونه های 6 هفته ای، میزان ماده پیوندی باقیمانده در گروه PDFDB به صورت قابل توجهی کمتر ازFDBA (04/0=P) بود، اما این تفاوت در نمونه های 12 هفته ای قابل توجه نبود (41/0=P). کیفیت استخوان تفاوت قابل توجهی بین گروه های حاوی گرفت استخوانی و گروه کنترل پس از 12 هفته نشان داد (01/0=P). بدین معنی که کلیه نمونه ها استخوان لاملار را پس از 12 هفته نشان دادند در حالی که در گروه کنترل، تنها استخوان woven یا ترکیبی از woven و لاملار دیده شد.
نتیجه گیریFDBA وPDFDB اثر رژنراتیو مشابهی در دیفکت های استخوانی کالواریای خرگوش نشان دادند و بلوغ استخوانی را نسبت به دیفکت های بدون پیوند تسریع کردند.
کلید واژگان: آلوگرفت, آزمایش حیوانی, رژنزاسیون استخوانی, ماده جایگزین استخوان, منجمد خشکBackground and AimsReconstruction of osseous defects is one of the ideal goals of periodontal treatments and dental implant therapy. Different biomaterials have been used for this purpose and many studies have tried to compare and introduce the best ones. The present study aimed to evaluate the effect of PDFDB (Partially Demineralized Freeze-Dried Bone Graft) and FDBA (Freeze Dried Bone Allograft) on the regeneration of rabbit calvarial defects.
Materials and MethodsIn this experimental study, 48 similar defects with the diameter of 8 mm were generated in the calvarium of 16 rabbits. Two defects were filled with FDBA and PDFDB, while the other one remained unfilled as the control group. All defects were covered by collagen membranes. 6 and 12 weeks after surgery, the histologic and histomorphometric tests were performed to evaluate the following variables: the rate of new bone formation and its type, the amount of residual grafting material, degree of inflammation and pattern of bone formation. Comparison of osteogenesis percentage and residual biomaterial was performed by repetitive variance analysis, whereas qualitative variables were compared by Friedman non-parametric test.
ResultsRegarding bone formation percentage, there was no statistically significant difference between three different groups at 6-week (P=0.33) and also at 12-week time points (P=0.98). The amount of residual material in the PDFDB group was significantly lower than FDBA (P=0.04) in the 6-week samples. However, this difference was not significant in the 12-week samples (P=0.41). Bone quality showed statistically significant difference between graft containing groups and control group after 12 weeks (P=0.01). It means, all samples in FDBA and PDFDB groups displayed lamellar bone after 12 weeks while in control group, only woven bone or a combination of woven and lamellar bone was seen.
ConclusionFDBA and PDFDB demonstrated similar regenerating effect in the rabbit calvarial bone defects and hastened bone maturation compared to the non-grafted defects.
Keywords: Allograft, Animal experiment, Bone regeneration, Bone replacement material, Freeze drying -
Journal of Dental Research, Dental Clinics, Dental Prospects, Volume:12 Issue: 4, Autumn 2018, PP 238 -244BackgroundEarly bone loss due to tooth extraction can be significantly reduced by socket preservation. The aim of this study was to compare the in vivo effects of hemihydrate calcium sulfate granules (an alloplastic material) and Cerabone (a bovine-derived xenograft) on socket preservation in dogs.MethodsSix male Mongrel dogs were randomly divided into 2 groups (n=3) for sacrificing and histological evaluation 4 and 8 weeks after a surgery. The second and third premolars on both sides of the lower jaw were extracted surgically. The sockets on one side were filled with Cerabone, and with calcium sulfate on the opposite side. In the slides, the ratio of the area of newly formed bone to the area of the entire cavity, and the ratio of the area of fibrous connective tissue to the area of the entire cavity were measured. The presence of inflammation was also examined. Wilcoxon signed-rank test, Sign test and McNemar test were used for statistical analyses (ɑ=0.05).ResultsThe means of new bone proportion were 11% and 8% for Cerabone and calcium sulfate, respectively (P=0.58). The means of connective tissue proportion were 29% and 33% for Cerabone and calcium sulfate, respectively (P=0.72). No inflammatory cells were observed in the Cerabone group, although 50% of the samples in the calcium sulfate group showed inflammation (P=0.50).ConclusionThe effects of calcium sulfate and Cerabone on socket preservation in dogs on bone formation, fibrous connective tissue and inflammation levels were not significantly different at 4- and 8-week postoperative intervals.Keywords: Animal experiment, calcium sulfate, Cerabone, dog, socket preservation
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