Meta-analysis reveals a specific association of the PNPLA3 I148M polymorphism with ALT level in adolescents.

AIM: To evaluate potential link between the PNPLA3 rs738409 polymorphism and alanine aminotransferase (ALT) levels through an evidence-based study. MATERIALS & METHODS: Electronic literature databases, including PubMed, Embase and the Institute for Scientific Information, were searched for relevant studies. Pooling standardized mean differences for quantitative variables and summary odds ratios (OR) were respectively calculated using per-allele comparison. RESULTS: Although a genotype-phenotype association was inconsistent in adults, this genetic effect was stable in adolescents. There was an approximate increase of 23% in ALT value, and 1.99-fold higher ALT elevation per risk allele increase with low heterogeneity. CONCLUSION: The PNPLA3 rs738409 polymorphism can have a differentiated influence on ALT level. Our meta-analysis provides reference data for the adjustment of diverse susceptibility due to the rs738409 polymorphism when evaluating liver injury in various populations.

[Old and new staging of endometrial carcinoma].

OBJECTIVE: To explore the rationality and clinical significance for the old and new surgical-pathological staging in endometrial carcinoma. METHODS: The clinical profiles and prognostic particulars were analyzed retrospectively in 92 cases of endometrial carcinoma from June 2005 to June 2011 at Xiaoshan Hospital. And the old and new surgical-pathological staging methods were applied to observe their rationality and treatment prognosis. RESULTS: There was 72.8% (67/92) for clinical stage I in the old surgical-pathological staging while 7.6% (7/92) for clinical stage II and 19.7% (18/92) for clinical stage III. There was 85.9% (79/92) for clinical stage I in the new surgical-pathological staging, 3.3% (3/92) for clinical stage IIand 10.7% (10/92) for clinical stage III. The detection rate of cancer cell was 8.7% (8/92) in peritoneal fluid. The positive rate of pelvic lymph node was 12.9% (11/85). A period of survival rates were compared among P > 0.05 after 3 years and 5 years of IA, IB and IIA. There was no statistical significance; there were statistical significance between IB and IC periods (P < 0.05). The survival of deep myometrial invasion was significantly shorter than that of superficial muscle layer. The positive rate of abdominal aortic lymph node was 3.8% (1/26). Six patients with positive lymph nodes died postoperatively of cancer within 4 to 28 months. CONCLUSION: The new surgical-pathological staging is more objective, practical, simple and convenient than its old counterpart. Deep myometrial infiltration and positive lymph node are important prognostic factors of endometrial carcinoma. The positive rate of lymph node remains low in early low-risk endometrial carcinoma and routine excision of lymph node is of little significance.

Correlation of corneal acoustic and elastic properties in a canine eye model.

PURPOSE: To examine the correlation between corneal acoustic impedance and Young's modulus in a canine eye model. METHODS: Twenty canine globes were recovered from healthy animals. Corneal acoustic impedance was measured in the intact globes using two methods: a quantitative ultrasound spectroscopy method and the reflection amplitude method. The intraocular pressure was maintained at 10 mm Hg during the ultrasound measurements. Corneal strips were then prepared for standard uniaxial tensile tests. Young's moduli at various strain levels and those at a loading level equivalent to that for ultrasound measurements were compared with the acoustic impedance of the same cornea. RESULTS: The mean acoustic impedance of the canine corneas was 1.72 ± 0.05 MPa · s/m using the quantitative ultrasound spectroscopy method and 1.71 ± 0.04 MPa · s/m using the reflection amplitude method. Young's secant modulus was 1.07 ± 0.48 MPa at 1% strain and 2.01 ± 0.98 MPa at 5% strain, and the tangent modulus was 1.28 ± 0.69 and 3.16 ± 0.71 MPa, respectively. Significant linear correlations between acoustic impedance and Young's modulus (at 1%-5% strains) were found in the measured canine corneas. The correlation remained strong when comparing the two parameters measured under equivalent loading. CONCLUSIONS: This study suggests a potentially strong correlation between corneal acoustic impedance and Young's modulus at low strain levels. If such correlation also exists in the human eye, it may allow the noninvasively determined acoustic impedance to be used as a surrogate for Young's modulus, which is difficult to obtain in vivo.

Measurement of corneal changes after collagen crosslinking using a noninvasive ultrasound system.

PURPOSE: To determine the changes in corneal properties induced by riboflavin-ultraviolet A (UVA) irradiation using a noninvasive ultrasound (US) method in a porcine eye model. SETTING: Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA. METHODS: Fresh porcine globes acquired within 24 hours postmortem were divided into equal groups. In the collagen crosslinking (CXL) group, the globes were irradiated with UVA in combination with riboflavin application following the standard protocol. The control group had the same procedures as the CXL group but with no UVA irradiation. Corneal properties were measured before and after treatments in both groups using a quantitative US method. Changes in corneal thickness, density, and stiffness were examined and the difference between the changes in the CXL group and the control group was analyzed. RESULTS: Each group comprised 14 porcine globes. After riboflavin-UVA treatment, there was a significant increase in corneal stiffness (mean 2.59 +/- 0.08 GPa before and 2.70 +/- 0.08 GPa after CXL) (P<.001) and in the speed of sound in corneal tissue (1557 +/- 23 m/s versus 1588 +/- 22 m/s) (P<.001). There was no significant change in corneal stiffness or in the speed of sound in the control group. Corneal thickness increased significantly after the treatment in both groups. No significant change in corneal density was observed in either group. CONCLUSION: Corneal stiffness increased after riboflavin-UVA CXL, a finding detected using a noninvasive US technique. FINANCIAL DISCLOSURE: Dr. Liu has filed a patent application for the general ultrasound technique used in the study. No other author has a financial or proprietary interest in any material or method mentioned.

A quantitative ultrasonic spectroscopy method for noninvasive determination of corneal biomechanical properties.

PURPOSE: To describe a quantitative ultrasonic spectroscopy technique for the noninvasive characterization of corneal biomechanical properties and to compare these measurements with established techniques in a porcine eye model. METHODS: An ultrasound system was constructed to accurately acquire acoustic reflections from corneas through a saline bath. Corneal properties (including thickness, density and aggregate modulus) were estimated from the measured reflection spectra based on wave propagation analysis. Twenty fresh porcine corneas were measured using the quantitative ultrasound method and other established techniques that can only be applied to dissected corneas. RESULTS: The ultrasonic measurements of corneal thickness and aggregate modulus were significantly correlated with the measurements of established techniques (Pearson's correlation = 0.99 and 0.61; P < 0.005), and good sample-to-sample consistency was achieved. The measurement of corneal density agreed well in terms of mean and range, but the correlation did not achieve statistical significance (Pearson's correlation = 0.41; P = 0.07). CONCLUSIONS: The ultrasonically measured corneal biomechanical properties agreed well with the measurements obtained by using established techniques, validating the accuracy of the ultrasound method. Quantitative ultrasound spectroscopy may provide a noninvasive approach for in vivo characterization of corneal biomechanical properties.

Corneal stiffness affects IOP elevation during rapid volume change in the eye.

PURPOSE: To investigate whether corneal stiffness affects the elevation of intraocular pressure after an acute increase in the volume of ocular fluid. METHODS: Saline (200 microL total) was infused into porcine globes before and after corneal stiffening. Intraocular pressure (IOP) was continuously monitored by a pressure sensor that was cannulated to the vitreous chamber. Corneal stiffening was achieved by immersing the corneas in a 1% or 4% glutaraldehyde solution for 20 minutes. Corneal strips were dissected from the globes, and the stress-strain relationships were measured. The mean secant modulus of each group of corneas at 5% strain was calculated. Control eyes with no corneal stiffening were also tested. RESULTS: A significantly higher IOP elevation was observed in the globes after the corneas were stiffened (mean +/- SD, 14.9 +/- 1.9 mm Hg before stiffening vs. 19.1 +/- 2.6 mm Hg after 1% glutaraldehyde treatment and 24.3 +/- 1.9 mm Hg after 4% glutaraldehyde treatment at 200 microL infusion; P < 0.001). The control group showed no change in IOP elevation. The 5% secant modulus was 0.46 +/- 0.24 MPa, 1.63 +/- 0.41 MPa, and 2.78 +/- 1.04 MPa (mean +/- SD), respectively for the original corneal tissue and tissue with 1% or 4% glutaraldehyde treatment. CONCLUSIONS: This study showed that stiffened corneas induced substantially higher IOP elevations when all other geometrical and material properties of the eye remained essentially the same. The results suggested that corneal stiffness may play an important role in determining IOP elevation caused by an acute increase in the volume of intraocular fluid.

Ultrasonic model and system for measurement of corneal biomechanical properties and validation on phantoms.

Non-invasive measurement of biomechanical properties of corneas may provide important information for ocular disease management and therapeutic procedures. An ultrasonic non-destructive evaluation method with a wave propagation model was developed to determine corneal biomechanical properties in vivo. In this study, we tested the feasibility of the approach in differentiating the mechanical properties of soft contact lenses as corneal phantoms. Three material types of soft contact lenses (six samples in each group) were measured using a broadband ultrasound transducer. The ultrasonic reflections from the contact lenses were recorded by a 500MHz/8-bit digitizer, and displayed and processed by a PC. A reference signal was recorded to compute the normalized power spectra using Fast Fourier Transformation. An inverse algorithm based on least-squares minimization was used to reconstruct three parameters of the contact lenses: density, thickness, and elastic constants lambda+2micro. The thickness of each sample was verified using an electronic thickness gauge, and the averaged density for each type of lenses was verified using Archimedes' principle and manufacturer's report. Our results demonstrated that the ultrasonic system was able to differentiate the elastic properties of the three types of the soft contact lenses with statistical significance (P-value<0.001). The reconstructed thicknesses and densities agreed well with the independent measurements. Our studies on corneal phantoms indicated that the ultrasonic system was sensitive and accurate in measuring the material properties of cornea-like structures. It is important to optimize the system for in vivo measurements.

Measurements of ocular properties in response to intraocular pressure changes using an ultrasonic system.

An ultrasonic system was developed to measure the biomechanical properties of intact corneas and determine the effects of an elevated intraocular pressure (IOP) on these properties. Accurate measurement of IOP is essential for early detection of blinding disease, glaucoma. Inter-subject variations of biomechanical properties may have introduced significant errors to IOP measurements using the current gold standard - Goldmann applanation tonometry. Therefore, it is important to develop a non-invasive method for measuring corneal biomechanical properties in vivo. In this study, an ultrasonic measurement technique in combination with a mathematical model for wave propagation in thin layers was developed to estimate cornea! properties and to differentiate the changes of the corneal properties in response to IOP changes in five enucleated porcine eyes. The measurements were performed with the IOPs adjusted at three different levels. Results showed that the ultrasonic method was sensitive to corneal property changes associated with IOP changes. We concluded that the ultrasonic method has the potential to implement non-invasive measurements of corneal properties in vivo.