The normally imprinted insulin-like growth factor II (IGF2) gene is aberrantly upregulated in a variety of human malignancies, yet the mechanisms underlying this dysregulation are still poorly defined. In this report, we used a CRISPR Cas9-guided chromatin immunoprecipitation assay to characterize the molecular components that participate in the control of IGF2 gene expression in human tumor cells. We found that miR483, an oncogenic intronic miRNA, binds to the most upstream imprinted IGF2 promoter, P2. Ectopic expression of miR483 induced upregulation of IGF2 expression, in parallel with an increase in tumor cell proliferation, migration, invasion, and tumor colony formation. miR483 induced loss of IGF2 imprinting by altering the epigenotype at P2, with reduction in histone H3K27 methylation and a decrease in chromatin binding of two imprinting regulatory factors, CTCF and SUZ12. This study identifies a new role for miR483 in the regulation of IGF2 gene expression through the alteration of the promoter epigenotype.

Trigeminal neuralgia affects approximately 182 in 100,000 Chinese, and the number keeps increasing these years. The role of surgery for patients with medically refractory trigeminal neuralgia is well established. Computed tomographic images provided by the First Affiliated Hospital of Jilin University were used to reconstruct the 3-dimensional skull models. We measured the positional relationship between oval foramen and trigeminal impression to analyze the relatively safe puncture angle for the internal carotid artery protection. Point O, A, and B are the projection of 3 points on plane C: the center of oval foramen, the medial edge of trigeminal impression, and the lateral edge of trigeminal impression, respectively. The length of OA was 11.02 mm (95% confidence interval [CI], 10.64-11.40 mm), and OB was 13.59 mm (95% CI, 13.20-13.98 mm). Angle study included the angle contained by the median sagittal plane and OA or OB, angle α or β, and the angle contained by OA and OB, angle γ. Angle α was 50.74 degrees (95% CI, 48.60-52.88 degrees). Angle β was 6.62 degrees (95% CI, 4.02-9.22 degrees). Angle γ was 44.12 degrees (95% CI, 41.95-46.29 degrees). So the ideal horizontal angle between the needle axis and the median sagittal plane ranges between angle α and β, 6.62 to 50.74 degrees, and the best puncture angle should be 33.18 degrees. The depth of needling insertion after entering the oval foramen should be less than the minimum length of the 95% CI of OA and OB, 10.64 mm.

The transsphenoidal approach to the pituitary is widely used in pituitary surgery. Even though there are some landmarks for internal carotid artery (ICA) on the wall of the sphenoid sinus, it is not rare to get the artery injured during surgery. We found that the most important landmark, carotid prominence, matched with ICA in merely 37.5% of subjects. In order to find a simple method to locate the artery, we made an anatomical measurement of the ICA and placed the results in a 3-dimensional coordinate system. The sphenoid sinus opening is both the center of the endoscope entry in the anterior sinus wall and the origin of the coordinate system containing 3 orthogonal axes: x, y, and z. The x axis follows the body of the endoscope(out of the sphenoid sinus) parallel to the sagittal plane while z is perpendicular to the sagittal plane. Most of the measurements were obtained in the initial operative plane, which is perpendicular to the sagittal plane and contains the sinus opening and the midpoint of the pituitary fossa. We calculated the coordinates of the midpoint of the pituitary fossa and 4 ICA-related points. The depth of an ICA and the distance between 2 ICAs are also helpful in locating ICA. According to our operation method, all the projective points of the medial edge of ICA on the posterior wall of the sphenoid sinus are lateral to the sphenoid sinus opening, and operating within 0-25 degrees medial to the endoscope body is believed to be safe from ICA injury.

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Trigeminal neuralgia is a common disease in Chinese people. Minimal invasive transforaminal pathway is widely used in treating trigeminal neuralgia. The Hartel pathway is the most commonly used operation route, but it has potential to injure vessels such as arteria meningea media and the internal carotid artery. We measured the location of operation route, foramen spinosum, and foramen lacerum in a three-dimensional pattern. We found that to protect those 2 vessels, the angle and depth of puncture should be well regulated. The horizontal component of the angle between the needle axis and y axis should be more than 22 degrees in women and 20 degrees in men to avoid the injury of arteria meningea media. And for protecting the internal carotid artery, the depth of puncture should be less than 85 mm for women and 93 mm for men, or less than 9 mm after penetrating the meninges.

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The aim of this study was to find a surgical approach to a vertical segment of the facial nerve (VFN) with a relatively wide visual field and small lesion by studying the location and structure of VFN with cross-sectional anatomy. High-resolution spiral computed tomographic multiplane reformation was used to reform images that were parallel to the Frankfort horizontal plane. To locate the VFN, we measured the distances as follows: from the VFN to the paries posterior bony external acoustic meatus on 5 typical multiplane reformation images, to the promontorium tympani and the root of the tympanic ring on 2 typical images. The mean distances from the VFN to the paries posterior bony external acoustic meatus are as follows: 4.47 mm on images showing the top of the external acoustic meatus, 4.20 mm on images with the best view of the window niche, 3.35 mm on images that show the widest external acoustic meatus, 4.22 mm on images with the inferior margin of the sulcus tympanicus, and 5.49 mm on images that show the bottom of the external acoustic meatus. The VFN is approximately 4.20 mm lateral to the promontorium tympani on images with the best view of the window niche and 4.12 mm lateral to the root of the tympanic ring on images with the inferior margin of the sulcus tympanicus. The other results indicate that the area and depth of the surgical wound from the improved approach would be much smaller than that from the typical approach. The surgical approach to the horizontal segment of the facial nerve through the external acoustic meatus and the tympanic cavity could be improved by grinding off the external acoustic meatus to show the VFN. The VFN can be found by taking the promontorium tympani and tympanic ring as references. This improvement is of high potential to expand the visual field to the facial nerve, remarkably without significant injury to the patients compared with the typical approach through the mastoid process.