[Show abstract][Hide abstract] ABSTRACT: AIM: To compare the tear functions and the impression cytology scores of the patients with primary open angle glaucoma (POAG), ocular hypertension (OHT) and normal subjects with healthy ocular surface both functionally and clinically.
METHODS: Eleven eyes of 11 patients with POAG (mean age: 62. 7 ± 6. 1y), 12 eyes of 12 patients (mean age: 62. 8 ± 6. 4y) with OHT and 12 eyes of 12 normal subjects (mean age: 62. 9 ± 6. 03y) were included to this prospective study. The patients with POAG and OHT had been recently diagnosed with these diseases and none of them had taken anti - glaucoma treatment before. In addition to conjunctival impression cytology, tear break-up time (TBUT) and basal Schirmer’s tests (BST) were performed. Impression cytology specimens of each group were graded and scored in the range of 0-3 according to Nelson’s method. Kruskal - Wallis analysis and Dunn’s multiple comparison tests were used for statistical analysis.
RESULTS: The mean BST values were 10.4±1.3, 10.9± 1.2 and 11.1±1.1 mm/5min of POAG, OHT and control groups respectively. The differences among the BST values of the POAG, OHT and control group were not statistically significant (P= 0. 33). The mean TBUT values were 11.2±1.1, 11.3± 1.1 and 11.8± 1.2s in POAG, OHT and normal subjects respectively. The differences among the BUT values of the POAG, OHT and control group were not statistically significant (P = 0. 35). Six eyes (54. 5%) revealed grade 0 and 5 eyes (45. 5%) revealed grade 1 impression cytology scores in POAG group. Six eyes (50%) revealed grade 0 and 6 eyes (50%) revealed grade 1 impression cytology scores in OHT group and 6 eyes 50%) revealed grade 0 and 6 eyes (50%) revealed grade 1 impression cytology scores in normal subjects ( P = 0. 97).
CONCLUSION: Oxidative stress may cause glaucoma, ocular surface diseases, lacrimal gland malfunction and a decrease in mucus secretion of goblet cells in all of the body. There were no significant differences between the impression cytology scores of patients with POAG, OHT and normal subjects.
[Show abstract][Hide abstract] ABSTRACT: We evaluated the effects of the oral nutritional supplement containing arginine, glutamine, and hydroxymethylbutyrate (Abound®) on healing of colonic anastomoses in experimental rat model. Seventy Wistar-Albino male rats were divided into seven groups. Colon transection and anastomosis were performed in all groups except for the sham group. In groups 2 and 5, rats were fed with standard rat chow after the operation. Oral nutritional supplement was added to standard nutrition for 3 days postoperatively in group 3 and 7 days in group 6 and preoperative 7 days plus postoperative 3 days in group 4 and preoperative 7 days plus postoperative 7 days in group 7. Bursting pressures were measured, adhesions were evaluated, and tissue samples were taken for measurement of tissue hydroxyproline levels and for histopathological examination. The usage of oral nutritional supplement had positive effects on bursting pressures, tissue hydroxyproline levels, and histopathological findings of anastomoses, but feeding with oral nutritional supplement both preoperatively and postoperatively had no additive effect on these parameters when compared with the groups that were fed only postoperatively. The mixture of arginine, glutamine, and hydroxymethylbutyrate may be safely used for achieving better healing results after colonic anastomoses.
Indian Journal of Surgery 01/2015; DOI:10.1007/s12262-015-1268-x · 0.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Atypical squamous cells 'cannot exclude high-grade squamous epithelial lesion' (ASC-H) cytology represents clear risk and has been a controversial issue in clinical practice. The objective of this study is to investigate the diagnostic performance of p16(INK4A) immunohistochemistry (IHC) among ASC-H Pap smears in predicting high-grade cervical intraepithelial lesions. Decolourisation and staining process with p16(INK4A) is applied to 27 ASC-H diagnosed conventional Pap smears, which were all managed with colposcopy-directed cervical biopsy priorly. Staining characteristics of ASC-H Pap smears are compared with histopathological data and sensitivity-specificity values of p16 triage to detect CIN2 + histopathology are determined. Overall sensitivity and specificity of positive p16(INK4A) immune staining to detect CIN2 + histopathology are found as 87.5% and 68%, respectively. Positive predictive value of p16 triage is found as 53.8% and negative predictive value is found as 92.8%. p16(INK4A) IHC seems applicable for conventional Pap smears and may provide an alternative triage option in ASC-H category.
Journal of Obstetrics and Gynaecology 07/2014; 34(8):1-5. DOI:10.3109/01443615.2014.930107 · 0.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To examine the integrity of the ocular surfaces of subjects with and without diabetes with no conjunctival and dry eye signs and symptoms and compare conjunctival impression cytology findings in diabetics with non-proliferative and proliferative diabetic retinopathy.
Conjunctival impression cytology was performed on 43 eyes of 43 subjects with non-proliferative diabetic retinopathy (NPDR), 42 eyes of 42 subjects with proliferative diabetic retinopathy (PDR), and 30 eyes of 30 control subjects. Impression cytology specimens of each group were graded and scored in the range 0-3 according to Nelson's method.
There were 45 (52.9%) women and 40 (47.1%) men. The mean age of the patients was 59.6±9.3y (range, 43-76y) in NPDR group and 58.0±8.8y (range, 41-85y) in PDR group. Cases with NPDR and PDR showed statistically significant higher impression cytology scores than control group (P<0.05). There was no difference between the NPDR and PDR patients for impression cytology grading scores.
It is determined that impression cytology grades are altered in patients with NPDR and PDR. Consequently, we suggest that there might be an association between the impression cytology grading scores and the severity of diabetic retinopathy.
International Journal of Ophthalmology 04/2014; 7(2):321-325. DOI:10.3980/j.issn.2222-3959.2014.02.23 · 0.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The purpose of our study is to investigate the effect of subconjunctival amniotic membrane free graft on subconjunctival fibrovascular reaction.
Twelve healthy male white New Zealand rabbits were used for the study. The rabbits were divided randomly into two groups: Study Group (n=6) and Control Group (n=6). In the Study Group, a 4mm limbal incision was made and a 4×4mm subconjunctival pocket was created with blunt dissection. A 4×4mm single layer of free amniotic membrane was placed in the pocket in an epithelium-up fashion without suturing. The limbal opening was secured with 10-0 nylon sutures on both sides. In the Control Group, a 4mm limbal incision was made, a 4×4mm subconjunctival pocket was created with blunt dissection, and the limbal opening was closed with 10-0 nylon sutures on both sides. After the first month, sclero-conjunctival blocks were obtained from the operated area and sections were stained with hematoxylin and eosin, Masson trichrome, and Ki67, SMA and CD34 antibodies.
The number of fibroblasts, lymphocytes and macrophages was significantly higher in the Study Group than in the Control Group. The number of Ki67- and SMA-positive cells, and CD34-positive vessels was also significantly higher in the Study Group. Amniotic membrane appeared to form folds in all the specimens.
The higher fibrovascular reaction shown by our histopathological examination indicates that free human amniotic membrane grafting without suturing is not useful in decreasing the subconjunctival fibrovascular reaction at the first postoperative month in rabbit eyes.
[Show abstract][Hide abstract] ABSTRACT: Objectif
Notre étude avait pour but d’examiner l’effet sur la réaction fibrovasculaire d’une transplantation de membrane amniotique libre sous la conjonctive.
Nous avons utilisé douze lapins blancs de Nouvelle-Zélande mâles et en bonne santé. Les lapins ont été répartis en deux groupes au hasard : le groupe à l’étude (n = 6) et le groupe témoin (n = 6). Dans le groupe à l’étude, on a effectué une incision limbique de 4 mm et créé une poche sous-conjonctivale de 4 × 4 mm à l’aide d’une dissection mousse. Une monocouche de membrane amniotique libre de 4 × 4 mm a été placée dans la poche sans effectuer de sutures de manière à ce que le haut de l’épithélium soit en position supérieure. L’ouverture limbique a été attachée des deux côtés à l’aide de sutures en nylon 10-0. Dans le groupe témoin, on a effectué une incision limbique de 4 mm et créé une poche sous-conjonctivale de 4 × 4 mm à l’aide d’une dissection mousse. Puis, l’ouverture limbique a été refermée des deux côtés à l’aide de sutures en nylon 10-0. À la fin du premier mois, on a obtenu des blocs scléroconjonctivaux à partir de la zone ayant subie l’opération puis on a effectué des coupes qui ont été colorées à l’hématoxyline, à l’éosine, au trichrome de Masson ainsi qu’aux anticorps Ki67, SMA et CD34.
Le nombre de fibroblastes, de lymphocytes et de macrophages était significativement supérieur dans le groupe à l’étude que dans le groupe témoin. De plus, le nombre de cellules positives au Ki67 et au SMA ainsi que le nombre de vaisseaux positifs au CD34 étaient significativement supérieurs dans le groupe à l’étude. La membrane amniotique semblait former des plis chez tous les spécimens.
La réaction fibrovasculaire supérieure démontrée par notre examen histopathologique indique que la transplantation d’une membrane amniotique libre sans sutures n’est pas utile pour diminuer la réaction fibrovasculaire sous-conjonctivale chez les lapins un mois après l’opération.
[Show abstract][Hide abstract] ABSTRACT: Intravascular papillary endothelial hyperplasia (IPEH) is a benign intravascular process with features mimicking other benign and malignant vascular proliferations. IPEH lesions predominate in the head-neck region and the extremities. The characteristic histomorphological feature of IPEH is a papillary structure covered with hyperplastic endothelial cells within the vascular lumen. It is critical that this clinically benign lesion should not be mistaken for well-differentiated vascular tumors. In addition to thecharacteristic histological features, other useful diagnostic features included the intra-luminal location of the lesion, an intimate association with the organizing thrombus, the absence of necrosis, cellular pleomorphism, and mitotic activity. In addition, immunohistochemistry may indicate the vascular origin and proliferative index. In this study, we evaluated histomorphological and immunohistochemical findings (CD31, CD34, FVIII, type IV collagen, SMA, MSA, CD105, and Ki-67 staining) of ten IPEH cases.
Ten IPEH cases were re-examined for a panel of histomorphological and immunohistochemical features. CD31, CD34, FVIII, Type IV collagen, SMA and MSA antibodies utilized for immunohistochemical analysis. The histomorphological and immunohistochemical findings were evaluated by two independent pathologists using light microscopy.
All ten cases involved intraluminal lesions with characteristic features of IPEH. All ten cases (100%) were stained positive for CD31 and CD34. The degree of staining with FVIII, type IV collagen, SMA, and MSA was variable.
In this series of specimens, CD31 and CD34 were the most sensitive markers indicating the vascular origin of the lesion. Staining for the other vascular markers (FVIII, type IV collagen, SMA and MSA) was variable. Different maturation degrees of lesions may account for the variation in immunohistochemical staining. Few previous investigations evaluated a wide range of antigen panels in IPEH sections. In our opinion, the evaluation of immune markers in a larger sample set will reveal new features in the maturity and developmental pathogenesis of vascular lesions and angiogenesis. IPEH is a benign lesion, which must be differentiated from malignant tumors such as angiosarcoma and Kaposi's sarcoma. Improved definition of IPEH lesions using immunohistochemical markers may enhance the ability to differentiate between various vascular lesions.Virtual slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1381849312101856.
[Show abstract][Hide abstract] ABSTRACT: Aim:
One of the most important causes of delayed discharge from hospital and
rehabilitation in patients undergone arthroscopy is postoperative pain. Intra-
articular analgesic injection is a new technique for pain control in such pa
tients and is a good alternative because of its limited systemic effects. This
brings up the question of whether these injections have unwanted effects on
the synovial tissue. The beneficial and side effects of intra-articular ketamine
injection after arthroscopy will be investigated in this study.
Twenty rats were included in the study. Ketamine was injected
at doses of 10 mg/kg (0,2 ml) to their right knee intra-articularly and same
amount of isotonic NaCl was injected into the their left knee as control group.
They were then sacrificed on days 1, 7, 14 and 21. The joints were labeled ac
cording to the day and direction. Samples were examined in Hematoxylin-
Eosin and Masson-Trichrome dye by light microscopy. Intra-articular, peri-ar
ticular and synovial inflammations were investigated in the knee joint.
Although inflammation was high for the group sacrificed the 1
after ketamine injection, we did not find a significant difference between rats
injected with saline and ketamine. There was no significant difference in the
number of synovial membrane-forming cells and subintimal fibrosis.
Patients with circulatory failure-disorders, advanced age, and co
morbidity may not have the same reaction to intra-articular ketamine, as did
the animals in our study. It should be investigated by further in vitro and wider studies.
[Show abstract][Hide abstract] ABSTRACT: To report a patient of lipoid proteinosis (LP) with bilateral keratoconus.
A 16-year-old boy presented to our institution with a complaint of gradual decrease in vision over the past 4 years in both eyes and a contact lens intolerance. He had a hoarse voice and multiple areas of hyperpigmented lesions over the head and neck region. Slit lamp biomicroscopy of the both eyes showed multiple round solid pearly lesions along the upper and lower lid margins and a mild central corneal ectasia in both eyes. Central corneal thickness and the keratometric values were measured by using Scheimpflug imaging (Pentacam), and the results were compatible with keratoconus. The histopathologic examination of the lesions taken from bilateral eyelid margins showed hyalinosis, papillomatosis, and depositions of eosinophilic material around the blood vessels, which were compatible with LP.
With this report, we describe a case of LP with keratoconus. As seen in our case, LP and its characteristic eyelid margin lesions in keratoconus patients can be associated with a contact lens intolerance.
[Show abstract][Hide abstract] ABSTRACT: Objectives:
Radioiodine (RAI) is used in the treatment of hyperthyroidism and differentiated thyroid cancer. Radioiodine therapy is associated with dry eyes and some side effects are seen especially due to beta rays. In this study, the functional and cytological status of lacrimal glands after RAI therapy was evaluated.
Twenty-five patients with a mean age of 55.16 years with planned low-dose RAI therapy were evaluated. Just before and 6 months after the treatment, the lacrimal glands were evaluated with tear break-up time (BUT), Schirmer's test, impression cytology and "Ocular Surface Disease Index (OSDI)" questionnaire.
The mean value of Schirmer's test was 16.20 ± 3.61 pre-treatment and 11.28 ± 4.39 post-treatment for the right eye, and 15.76 ± 3.27 and 10.60 ± 4.42 for the left eye, respectively. The mean value of Schirmer's test decreased significantly post-treatment in both eyes (p = 0.0001). The BUT score also decreased significantly post-treatment (p = 0.001). The mean value of OSDI score was 27.5 ± 8.02 pre-treatment and 46.36 ± 10.27 post-treatment. The mean value of OSDI score increased post-treatment (p = 0.0001). The impression scores also increased post-treatment in both eyes (p = 0.0001).
Even low-dose (≤30 mci) RAI treatment affects lacrimal gland functions. Low-dose RAI causes a decrease in the value of Schirmer's test and the BUT test, and an increase in the value of OSDI score and impression scores.
Annals of Nuclear Medicine 02/2013; 27(8). DOI:10.1007/s12149-013-0705-9 · 1.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose. Using the classical Ankaferd Blood Stopper (ABS) solution to create active hemostasis during partial nephrectomy (PN) may not be so effective due to insufficient contact surface between the ABS hemostatic liquid agent and the bleeding area. In order to broaden the contact surface, we generated a chimeric hemostatic agent, ABS nanohemostat, via combining a self-assembling peptide amphiphile molecule with the traditional Ankaferd hemostat. Materials and Methods. In order to generate ABS nanohemostat, a positively charged Peptide Amphiphile (PA) molecule was synthesized by using solid phase peptide synthesis. For animal experiments, 24 Wistar rats were divided into the following 4 groups: Group 1: control; Group 2: conventional PN with only 0.5 ml Ankaferd hemostat; Group 3: conventional PN with ABS + peptide gel; Group 4: conventional PN with only 0.5 ml peptide solution. Results. Mean warm ischemia times (WITs) were 232.8 ± 56.3, 65.6 ± 11.4, 75.5 ± 17.2, and 58.1 ± 17.6 seconds in Group 1 to Group 4, respectively. Fibrosis was not different among the groups, while inflammation was detected to be significantly different in G3 and G4. Conclusions. ABS nanohemostat has comparable hemostatic efficacy to the traditional Ankaferd hemostat in the partial nephrectomy experimental model. Elucidation of the cellular and tissue effects of this chimeric compound may establish a catalytic spark and open new avenues for novel experimental and clinical studies in the battlefield of hemostasis.
International Journal of Biomaterials 02/2013; 2013(4):949460. DOI:10.1155/2013/949460
[Show abstract][Hide abstract] ABSTRACT: Porcine acellular dermal collagen (PDC), which is a biological material derived from processing porcine dermis, has already been used for urologic, gynecologic, plastic, and general surgery procedures up to now. The aim of this study is to investigate the effectiveness of PDC on wound healing as a dermal substitute in the rat model. Twenty Wistar albino rats were divided into two groups. Standard full-thickness skin defects were created on the back of the rats. In the control group (Group 1), the dressings moisturized with saline were changed daily. In the study group (Group 2), porcine dermal collagen was implanted onto each wound and fixed with 4–0 polypropylene sutures. Contraction percentages of wound areas were calculated on the third, seventh, tenth, and fourteenth days by using the planimetric program. On fourteenth day, the wound areas were excised for histopathological examination, inflammatory scoring, and evaluation of collagen deposition. The study group was superior to the control group in terms of inflammatory scoring, type I/type III collagen ratio, and wound contraction rates. Porcine dermal collagen may be used effectively and safely on full-thickness wounds as a current dermal substitute.
Indian Journal of Surgery 01/2013; DOI:10.1007/s12262-013-0854-z · 0.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fibroadenoma is a frequent benign breast lesion among women in fertile age. It may manifest as synchronous or asynchronous multiple nodules although not often. Total infarction has rarely been reported in fibroadenoma where the vast majority are infarctions that develop following fine needle aspiration. Spontaneous infarctions reported in the literature are few and develop in 0.5-1.5 of all fibroadenomas and especially during pregnancy or lactation. As it is a rare entity, it may be confused with inflammatory diseases and necrotic carcinomas of the breast both clinically and with limited pathological methods like fine needle aspiration cytology, needle biopsy, and frozen section. In this paper, we reported findings of spontaneous infarction in multiple fibroadenoma in a 19-year-old postlactational woman. The case was worth presenting because infarction had developed in more than one fibroadenoma spontaneously.
Turkiye Klinikleri Journal of Medical Sciences 10/2012; 32(5):1429-1432. DOI:10.5336/medsci.2010-22098 · 0.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ankaferd Blood Stopper® (ABS) is a folkloric medicinal plant extract used as a haemostatic agent in traditional Turkish medicine. The aim of this study was to investigate the efficacy of ABS on the healing of dermal wounds in a rat model. Twenty Wistar albino rats were divided into two groups. Standard full-thickness skin defects were created on the back of the rats. In the control group (group 1), dressings moisturised with saline were changed daily. In the study group (group 2), the wounds were cleaned daily with saline, Ankaferd solution was applied, then the wounds were covered with moisturised dressings. The contraction percentage of wound areas were calculated on the 3rd, 7th, 10th and 14th days using a planimetric program. On day 14, the wound areas were excised for histopathological examination, inflammatory scoring and evaluation of collagen deposition. The study group was superior to the control group in terms of inflammatory scoring, type I/type III collagen ratio and wound contraction rates. ABS® may be used effectively and safely on full-thickness wounds as a natural product.
International Wound Journal 09/2012; 11(1). DOI:10.1111/j.1742-481X.2012.01063.x · 2.15 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study is to investigate the effect of formoterol (β2 adrenergic receptor agonist) on peritoneal VEGF levels in rats with endometriosis.
Experimental endometriosis was constituted with implantation of endometrial tissue. The implants were examined by second laparatomy and rats were divided randomly into four groups. One cc saline was applied ip to the control (C) group (n=8) daily, 22.5μg/kg/day ip formoterol was applied to the second (F) group (n=10) daily, 22.5μg/kg/day ip formoterol and 10mg/kg/day ip propranolol were applied to the third (FP) group (n=10) daily, 45μg/kg/day ip formoterol was applied to the fourth (FF) group (n=9). Before treatment and after 30 days treatment period, peritoneal VEGF levels, the volumes and histopathological properties of the implants were evaluated.
There were significant differences in between the peritoneal VEGF levels before and after treatment in group 2(F) and group 4(FF) (p(a): 0.01, 0.01 respectively). But there were no significant changes in between the volumes of implants before and after treatment among the groups (p>0.05). There were no significant differences among the groups in histopathological parameters (p>0.05).
Formoterol treatment was seen to have no effect on the volumes and histopathological structure of endometriotic implants in our study. On the other hand, based on the group 2(F) and 4's (FF) VEGF levels after the treatment, low dose or high dose formoterol may be effective with long term therapy. Formoterol may reduce the development of endometriosis.
[Show abstract][Hide abstract] ABSTRACT: An antibacterial drug, ciprofloxacin, has been reported to modulate the inflammatory and immune responses on monocytes. Our objective is to evaluate the effectiveness of ciprofloxacin in the prevention of myringosclerosis that is created by myringotomy in rats and to compare it with prednisolone. In this study, 24 healthy Sprague-Dawley type rats of age 3-4 months and 250-300 g weight were used. Rats have been divided into three random groups. Topical ciprofloxacin was administered to the rats in the first group and topical prednisolone was administered to the rats in the third group; no medication was applied to their opposite ears and they were determined as control group. Prednisolone was administered to one ear of the rats and ciprofloxacin was administered to their opposite sides in the second group. After bilateral myringotomies the treatments were applied for 20 days as five drops two times a day. Otomicroscopic examination was made on the 10th day and reperforations were made when necessary. Rats were killed on the 21st day and temporal bone dissections were done. When we evaluate in terms of myringosclerosis and tympanic membrane thickness, in the first group, myringosclerosis and thickness have been observed in two of seven ears (28.6%) where ciprofloxacin was administered and in five of the seven ears (71.4%) where no treatment was applied. In the second group where prednisolone and ciprofloxacin were compared, myringosclerosis and thickness have been observed in six of the ten ears (60.0%) where prednisolone was administered and in four of the ten ears (40.0%) where ciprofloxacin was administered. In the third group, myringosclerosis and thickness have been observed in three of seven ears (42.9%) where prednisolone was administered and in four of the seven ears (57.1%) where no treatment was applied. All histopathological evaluations were made by one pathologist in a blinded manner. In our study, the effect of the ciprofloxacin and prednisolone was similar in preventing the experimental myringosclerosis and TM thickness in rats. When compared with the control groups, this preventive effect was more obvious in the ciprofloxacin treatment group than that of prednisolone.
Archives of Oto-Rhino-Laryngology 12/2011; 269(11):2335-41. DOI:10.1007/s00405-011-1889-z · 1.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of our study was to investigate the effect of the topical use of mitomycin C (MMC) intraoperatively in single dose and intra-postoperatively in two doses on the narrowing of antrostomy in maxillary rabbit sinus antrostomies created experimentally. And also to determine the local and systemic side effects of topical MMC. With this objective, 0.6 mg/ml MMC was used to the first group at single dose and to the second group intraoperatively and on third day postoperatively in two doses topically for 5 min. After 8 weeks, although the mean area of antrostomy was larger than that in the control side in the first group, which received single dose MMC, the difference was not statistically significant (p = 0.287). The second group received two doses, and the antrostomy areas were found to be significantly larger than the controls (p = 0.05). Overall, the sides that received MMC were significantly larger (p = 0.029). From the point of histopathological examination of the tissue, it was seen that two-dose MMC increased the edema indicating inflammation and antrostomy resolved with normal respiratory tract epithelium. It was shown by measuring the blood values that nephrotoxic and myelosupressant effect of MMC occurring in systemic use did not occur with single or double dose topical use. Our results demonstrate that even if the number of cases was low, two doses of topical MMC usage prevent the narrowing of antrostomy while single dose MMC does not. And two-dose topical MMC usage does not have local and systemic side effects.
Archives of Oto-Rhino-Laryngology 06/2011; 268(11):1597-603. DOI:10.1007/s00405-011-1648-1 · 1.55 Impact Factor