Predicting tumor deposits in rectal cancer: a combined deep learning model using T2-MR imaging and clinical features.

BACKGROUND: Tumor deposits (TDs) are associated with poor prognosis in rectal cancer (RC). This study aims to develop and validate a deep learning (DL) model incorporating T2-MR image and clinical factors for the preoperative prediction of TDs in RC patients. METHODS AND METHODS: A total of 327 RC patients with pathologically confirmed TDs status from January 2016 to December 2019 were retrospectively recruited, and the T2-MR images and clinical variables were collected. Patients were randomly split into a development dataset (n = 246) and an independent testing dataset (n = 81). A single-channel DL model, a multi-channel DL model, a hybrid DL model, and a clinical model were constructed. The performance of these predictive models was assessed by using receiver operating characteristics (ROC) analysis and decision curve analysis (DCA). RESULTS: The areas under the curves (AUCs) of the clinical, single-DL, multi-DL, and hybrid-DL models were 0.734 (95% CI, 0.674-0.788), 0.710 (95% CI, 0.649-0.766), 0.767 (95% CI, 0.710-0.819), and 0.857 (95% CI, 0.807-0.898) in the development dataset. The AUC of the hybrid-DL model was significantly higher than the single-DL and multi-DL models (both p < 0.001) in the development dataset, and the single-DL model (p = 0.028) in the testing dataset. Decision curve analysis demonstrated the hybrid-DL model had higher net benefit than other models across the majority range of threshold probabilities. CONCLUSIONS: The proposed hybrid-DL model achieved good predictive efficacy and could be used to predict tumor deposits in rectal cancer. CRITICAL RELEVANCE STATEMENT: The proposed hybrid-DL model achieved good predictive efficacy and could be used to predict tumor deposits in rectal cancer. KEY POINTS: • Preoperative non-invasive identification of TDs is of great clinical significance. • The combined hybrid-DL model achieved good predictive efficacy and could be used to predict tumor deposits in rectal cancer. • A preoperative nomogram provides gastroenterologist with an accurate and effective tool.

A nomogram for preoperative differentiation of tumor deposits from lymph node metastasis in rectal cancer: A retrospective study.

The objective is to develop and validate a combined model for noninvasive preoperative differentiating tumor deposits (TDs) from lymph node metastasis (LNM) in patients with rectal cancer (RC). A total of 204 patients were enrolled and randomly divided into 2 sets (training and validation set) at a ratio of 8:2. Radiomics features of tumor and peritumor fat were extracted by using Pyradiomics software from the axial T2-weighted imaging of MRI. Rad-score based on extracted Radiomics features were calculated by combination of feature selection and the machine learning method. Factors (Rad-score, laboratory test factor, clinical factor, traditional characters of tumor on MRI) with statistical significance were integrated to build a combined model. The combined model was visualized by a nomogram, and its distinguish ability, diagnostic accuracy, and clinical utility were evaluated by the receiver operating characteristic curve (ROC) analysis, calibration curve, and clinical decision curve, respectively. Carbohydrate antigen (CA) 19-9, MRI reported node stage (MRI-N stage), tumor volume (cm3), and Rad-score were all included in the combined model (odds ratio = 3.881 for Rad-score, 2.859 for CA19-9, 0.411 for MRI-N stage, and 1.055 for tumor volume). The distinguish ability of the combined model in the training and validation cohorts was area under the summary receiver operating characteristic curve (AUC) = 0.863, 95% confidence interval (CI): 0.8-0.911 and 0.815, 95% CI: 0.663-0.919, respectively. And the combined model outperformed the clinical model in both training and validation cohorts (AUC = 0.863 vs 0.749, 0.815 vs 0.627, P = .0022, .0302), outperformed the Rad-score model only in training cohorts (AUC = 0.863 vs 0.819, P = .0283). The combined model had highest net benefit and showed good diagnostic accuracy. The combined model incorporating Rad-score and clinical factors could provide a preoperative differentiation of TD from LNM and guide clinicians in making individualized treatment strategy for patients with RC.

Nomogram including tumor deposition count to noninvasively evaluate the prognosis of rectal cancer patients: A retrospective study.

To build a nomogram model that includes tumor deposition (TDs) count to noninvasively evaluate the prognosis of patients with rectal cancer (RC). A total of 262 patients between January 2013 and December 2018 were recruited and divided into 2 cohorts: training (n = 171) and validation (n = 91). Axial portal venous phase computed tomography images were used to extract radiomic features, and the least absolute shrinkage and selection operator-Cox analysis was applied to develop an optimal radiomics model to derive the Rad-score. A Cox regression model combining clinicopathological factors and Rad-scores was constructed and visualized using a nomogram. And its ability to predict RC patients' survival was tested by Kaplan-Meier survival analysis. The time-dependent concordance index curve was used to demonstrate the differentiation degree of model. Calibration and decision curve analyses were used to evaluate the calibration accuracy and clinical usefulness of the nomogram model, and the prediction performance of the nomogram model was compared with the clinical and radiomics models using the likelihood test. Computed tomography-based Rad-score, pathological tumor (pT) stageT4, and TDs count were independent risk factors affecting the prognosis of RC. The whole concordance index of the nomogram model for predicting the overall survival rates of RC was higher than that of the clinical and radiomics models in the training (0.812 vs 0.59, P = .019; 0.812 vs 0.714, P = .014) and validation groups (0.725 vs 0.585, P = .002; 0.725 vs 0.751, P = .256). The nomogram model could effectively predict patients' overall survival rate (hazard ratio = 9.25, 95% CI = [1.17-72.99], P = .01). The nomogram model also showed a higher clinical net benefit than the clinical and radiomics models in the training and validation groups. The nomogram model developed in this study can be used to noninvasively evaluate the prognosis of RC patients. The TDs count is an independent risk factor for the prognosis of RC.

Care practices and short-term clinical outcomes of very low birth weight infants in Yangtze River Delta in China.

BACKGROUND: Intensive care is of great significance for very low birth weight infants (VLBWI). The Yangtze River Delta is the most ecomonically developed area in China. However, there are few data on the care practices and survival of VLBWI in this region. OBJECTIVES: To investigate the prevalence, care practices and motality of VLBWI in Yangtze River Delta in China. METHODS: A multi-center retrospective investigation study was conducted at five tertiary hospitals within the Yangtze River Delta in China from January to December 2017. Clinical data included the general characteristics of the infants and the mothers, clinical prognosis, care practices in NICUs was collected by trained research members. RESULTS: During the study period, 1059 VLBWIs were included. Infants with birth weight < 750 g, 750-1000 g, 1000-1250 g and 1250-1500 g accounted for 2.3, 14.9, 34.8 and 47.8%, respectively. Premature rupture of membranes (17.8%) was the main cause of premature delivery. The catheterization rates of umbilical vein catheterization (UVC) and peripherally inserted central catheter (PICC) were 25.0 and 64.4%, respectively. The duration of parenteral nutrition was 27.0 ± 19.5 d, the meantime of feeding tube indwelling was 36.2 ± 24.2 d. The corrected gestational age of the infants who reached full oral feeding was 35.8 ± 2.7 weeks. The breast feeding rate in the investigated infants was 61.9%. The mortality rate of preterm infants was 3.4%. The incidence of main complications BPD, PDA, ROP, NEC and sepsis were 24.9, 29.9, 21.7, 9.4 and 13.3% respectively. CONCLUSIONS: Maternal and infant care practices need to be improved in the very preterm births. This study provides a baseline for the improvement in the further study.

Diagnostic performance of mono-exponential DWI versus diffusion kurtosis imaging in breast lesions: A meta-analysis.

BACKGROUND: This meta-analysis aimed to explore the diagnostic value of diffusion kurtosis imaging (DKI) compared to mono-exponential diffusion weighted imaging (DWI) in the diagnosis of breast cancer. METHODS: A systematic electronic literature search (up to September 2020) was conducted for published English-language studies comparing the diagnostic values of DKI and DWI for the detection of breast cancer. The data of mean kurtosis (MK), mean diffusivity (MD), and apparent diffusion coefficient (ADC) were extracted to construct 2 × 2 contingency tables. The pooled sensitivities, specificities, and areas under the receiver operating characteristic curve (AUCs) were compared between DKI and DWI in the diagnosis of breast cancer. RESULTS: Eight studies were finally included, with a total of 771 patients in the same population. Pooled sensitivities were 82.0% [95% confidence interval (95% CI), 78.2-85.3%] for ADC, 87.3% (95% CI, 83.9-90.1%) for MK, and 83.9% (95% CI, 80.2-87.1%) for MD. Pooled specificities were 81.1% (95% CI, 76.7-84.9%) for ADC, 85.1% (95% CI, 81.1-88.5%) for MK, and 83.2% (95% CI, 79.0-86.8%) for MD. According to the summary receiver operator characteristic curve analyses, the AUCwas 0.901 for ADC, 0.930 for MK, and 0.918 for MD (ADC vs MK, P = .353; ADC vs MD, P = .611). No notable publication bias was found, while significant heterogeneity was observed. CONCLUSIONS: Although DKI is feasible for identifying breast cancer, MD and MK offer similar diagnostic performance to ADC values. Thus, we recommend that DKI should not be included in the routine evaluation of breast lesions now.

Radiomics for differentiating tumor deposits from lymph node metastasis in rectal cancer.

BACKGROUND: Tumor deposits (TDs) are not equivalent to lymph node (LN) metastasis (LNM) but have become independent adverse prognostic factors in patients with rectal cancer (RC). Although preoperatively differentiating TDs and LNMs is helpful in designing individualized treatment strategies and achieving improved prognoses, it is a challenging task. AIM: To establish a computed tomography (CT)-based radiomics model for preoperatively differentiating TDs from LNM in patients with RC. METHODS: This study retrospectively enrolled 219 patients with RC [TDs+LNM- (n = 89); LNM+ TDs- (n = 115); TDs+LNM+ (n = 15)] from a single center between September 2016 and September 2021. Single-positive patients (i.e., TDs+LNM- and LNM+TDs-) were classified into the training (n = 163) and validation (n = 41) sets. We extracted numerous features from the enhanced CT (region 1: The main tumor; region 2: The largest peritumoral nodule). After deleting redundant features, three feature selection methods and three machine learning methods were used to select the best-performing classifier as the radiomics model (Rad-score). After validating Rad-score, its performance was further evaluated in the field of diagnosing double-positive patients (i.e., TDs+LNM+) by outlining all peritumoral nodules with diameter (short-axis) > 3 mm. RESULTS: Rad-score 1 (radiomics signature of the main tumor) had an area under the curve (AUC) of 0.768 on the training dataset and 0.700 on the validation dataset. Rad-score 2 (radiomics signature of the largest peritumoral nodule) had a higher AUC (training set: 0.940; validation set: 0.918) than Rad-score 1. Clinical factors, including age, gender, location of RC, tumor markers, and radiological features of the largest peritumoral nodule, were excluded by logistic regression. Thus, the combined model was comprised of Rad-scores of 1 and 2. Considering that the combined model had similar AUCs with Rad-score 2 (P = 0.134 in the training set and 0.594 in the validation set), Rad-score 2 was used as the final model. For the diagnosis of double-positive patients in the mixed group [TDs+LNM+ (n = 15); single-positive (n = 15)], Rad-score 2 demonstrated moderate performance (sensitivity, 73.3%; specificity, 66.6%; and accuracy, 70.0%). CONCLUSION: Radiomics analysis based on the largest peritumoral nodule can be helpful in preoperatively differentiating between TDs and LNM.

The carbon catabolite repressor CreA is an essential virulence factor of Metarhizium acridum against Locusta migratoria.

BACKGROUND: CreA has been proved to be a core gene in asexual conidiation in Metarhizium acridum, which regulates the shift of normal conidiation and microcycle conidiation. At present, research on CreA in fungi has focused on carbon source metabolism. There is a lack of research on the effect of CreA in virulence of pathogenic fungi. RESULTS: The virulence of the MaCreA disrupted strain (ΔMaCreA) for Locusta migratoria was lost by topical inoculation bioassay. The formation rate and turgor pressure of the appressoria decreased. Growth of ΔMaCreA in host hemolymph was delayed, and the number of hyphal bodies was significantly reduced. The conidial cell wall of ΔMaCreA became thicker, the mannan content decreased, and the chitin content increased significantly, and it was more sensitive to calcofluor white and Congo Red. α-1,3-Glucan and ß-1,3-glucan are more exposed on the surface of ΔMaCreA conidia than on the wild type. Lmspätzle and Lmcactus, the immune response genes in the host Toll pathway, showed stronger transcriptional activities at the early stage of ΔMaCreA invasion. The phenoloxidase activity assay also showed stronger immunostimulation by ΔMaCreA in vitro. CONCLUSION: The main reasons for the loss of virulence of ΔMaCreA in the topical inoculation were the reduced penetration ability of appressoria, limited growth in hemolymph and stronger insect immunostimulation of ΔMaCreA. © 2022 Society of Chemical Industry.

Computed tomography-based radiomics for predicting lymphovascular invasion in rectal cancer.

PURPOSE: To develop and externally validate a computed tomography (CT)-based radiomics model for predicting lymphovascular invasion (LVI) before treatment in patients with rectal cancer (RC). METHOD: This retrospective study enrolled 351 patients with RC from three hospitals between March 2018 and March 2021. These patients were assigned to one of the following three groups: training set (n = 239, from hospital 1), internal validation set (n = 60, from hospital 1), and external validation set (n = 52, from hospitals 2 and 3). Large amounts of radiomics features were extracted from the intratumoral and peritumoral regions in the portal venous phase contrast-enhanced CT images. The score of radiomics features (Rad-score) was calculated by performing logistic regression analysis following the L1-based method. A combined model (Rad-score + clinical factors) was developed in the training cohort and validated internally and externally. The models were compared using the area under the receiver operating characteristic curve (AUC). RESULTS: Of the 351 patients, 106 (30.2%) had an LVI + tumor. Rad-score (comprised of 22 features) was significantly higher in the LVI + group than in the LVI- group (0.60 ± 0.17 vs. 0.42 ± 0.19, P = 0.001). The combined model obtained good predictive performance in the training cohort (AUC = 0.813 [95% CI: 0.758-0.861]), with robust results in internal and external validations (AUC = 0.843 [95% CI: 0.726-0.924] and 0.807 [95% CI: 0.674-0.903]). CONCLUSIONS: The proposed combined model demonstrated the potential to predict LVI preoperatively in patients with RC.

Computed Tomography-Based Radiomics for Preoperative Prediction of Tumor Deposits in Rectal Cancer.

OBJECTIVE: To develop and validate a computed tomography (CT)-based radiomics model for predicting tumor deposits (TDs) preoperatively in patients with rectal cancer (RC). METHODS: This retrospective study enrolled 254 patients with pathologically confirmed RC between December 2017 and December 2019. Patients were divided into a training set (n = 203) and a validation set (n = 51). A large number of radiomics features were extracted from the portal venous phase images of CT. After selecting features with L1-based method, we established Rad-score by using the logistic regression analysis. Furthermore, a combined model incorporating Rad-score and clinical factors was developed and visualized as the nomogram. The models were evaluated by the receiver operating characteristic curve (ROC) analysis and area under the ROC curve (AUC). RESULTS: One hundred and seventeen of 254 patients were eventually found to be TDs+. Rad-score and clinical factors including carbohydrate antigen (CA) 19-9, CT-reported T stage (cT), and CT-reported peritumoral nodules (+/-) were significantly different between the TDs+ and TDs- groups (all P < 0.001). These factors were all included in the combined model by the logistic regression analysis (odds ratio = 2.378 for Rad-score, 2.253 for CA19-9, 2.281 for cT, and 4.485 for peritumoral nodules). This model showed good performance to predict TDs in the training and validation cohorts (AUC = 0.830 and 0.832, respectively). Furthermore, the combined model outperformed the clinical model incorporating CA19-9, cT, and peritumoral nodules (+/-) in both training and validation cohorts for predicting TDs preoperatively (AUC = 0.773 and 0.718, P = 0.008 and 0.039). CONCLUSIONS: The combined model incorporating Rad-score and clinical factors could provide a preoperative prediction of TDs and help clinicians guide individualized treatment for RC patients.

Radiomics for predicting perineural invasion status in rectal cancer.

BACKGROUND: Perineural invasion (PNI), as a key pathological feature of tumor spread, has emerged as an independent prognostic factor in patients with rectal cancer (RC). The preoperative stratification of RC patients according to PNI status is beneficial for individualized treatment and improved prognosis. However, the preoperative evaluation of PNI status is still challenging. AIM: To establish a radiomics model for evaluating PNI status preoperatively in RC patients. METHODS: This retrospective study enrolled 303 RC patients in a single institution from March 2018 to October 2019. These patients were classified as the training cohort (n = 242) and validation cohort (n = 61) at a ratio of 8:2. A large number of intra- and peritumoral radiomics features were extracted from portal venous phase images of computed tomography (CT). After deleting redundant features, we tested different feature selection (n = 6) and machine-learning (n = 14) methods to form 84 classifiers. The best performing classifier was then selected to establish Rad-score. Finally, the clinicoradiological model (combined model) was developed by combining Rad-score with clinical factors. These models for predicting PNI were compared using receiver operating characteristic curve (ROC) analysis and area under the ROC curve (AUC). RESULTS: One hundred and forty-four of the 303 patients were eventually found to be PNI-positive. Clinical factors including CT-reported T stage (cT), N stage (cN), and carcinoembryonic antigen (CEA) level were independent risk factors for predicting PNI preoperatively. We established Rad-score by logistic regression analysis after selecting features with the L1-based method. The combined model was developed by combining Rad-score with cT, cN, and CEA. The combined model showed good performance to predict PNI status, with an AUC of 0.828 [95% confidence interval (CI): 0.774-0.873] in the training cohort and 0.801 (95%CI: 0.679-0.892) in the validation cohort. For comparison of the models, the combined model achieved a higher AUC than the clinical model (cT + cN + CEA) achieved (P < 0.001 in the training cohort, and P = 0.045 in the validation cohort). CONCLUSION: The combined model incorporating Rad-score and clinical factors can provide an individualized evaluation of PNI status and help clinicians guide individualized treatment of RC patients.

An herbal cream reduces erythema of sensitive skin.

BACKGROUND: Sensitive skin manifests itself as a syndrome defined by the occurrence of unpleasant sensations such as stinging, burning, and pruritus. Though not life-threatening, it can negatively impact the quality of people's lives because of symptoms and clinical signs. Although some skin care products can alleviate symptoms of sensitive skin, a product that can improve multiple abnormalities of sensitive skin are largely unavailable. AIMS: To assess the efficacy of a newly developed herbal cream in reducing erythema. METHODS: A randomized double-blind and self-controlled trial was carried out on a total of 35 volunteers. The test cream (A) was applied topically to one side of the face twice-daily, while the control cream (B) was applied to the other side of the face. Parameters were evaluated prior to, 14, and 28 days after topical applications. Primary endpoints included changes in erythema area, erythema index (EI), and a* value. Transepidermal water loss rates (TEWL), stratum corneum (SC) hydration, and lactic acid sting test (LAST) score, as well as the L* value, served as secondary endpoints. RESULT: Treatments with either cream A or B markedly reduced erythema area, EI, and a* value. Significant reductions in both TEWL and L* value were also observed following topical applications of either cream A or B. Moreover, cream A decreased LAST score. Finally, the satisfaction rate of cream A was higher than that of cream B. CONCLUSION: The new herbal cream improves cutaneous biophysical properties in subjects with sensitive skin, especially in reducing erythema.

Shaft Function of Kinesin-1's α4 Helix in the Processive Movement.

INTRODUCTION: Kinesin-1 motor is a molecular walking machine constructed with amino acids. The understanding of how those structural elements play their mechanical roles is the key to the understanding of kinesin-1 mechanism. METHODS: Using molecular dynamics simulations, we investigate the role of a helix structure, α4 (also called switch-II helix), of kinesin-1's motor domain in its processive movement along microtubule. RESULTS: Through the analysis of the structure and the interactions between α4 and the surrounding residues in different nucleotide-binding states, we find that, mechanically, this helix functions as a shaft for kinesin-1's motor-domain rotation and, structurally, it is an amphipathic helix ensuring its shaft functioning. The hydrophobic side of α4 consists strictly of hydrophobic residues, making it behave like a lubricated surface in contact with the core ß-sheet of kinesin-1's motor domain. The opposite hydrophilic side of α4 leans firmly against microtubule with charged residues locating at both ends to facilitate its positioning onto the intra-tubulin groove. CONCLUSIONS: The special structural feature of α4 makes for an effective reduction of the conformational work in kinesin-1's force generation process.

Anchor Effect of Interactions Between Kinesin's Nucleotide-Binding Pocket and Microtubule.

Microtubule not only provides the track for kinesin but also modulates kinesin's mechanochemical cycle. Microtubule binding greatly increases the rates of two chemical steps occurring inside the nucleotide-binding pocket (NBP) of kinesin, i.e., ATP hydrolysis and ADP release. Kinesin neck linker docking (the key force-generation step) is initiated by the motor head rotation induced by ATP binding which needs an anchor provided by microtubule. These functions of microtubule can only be accomplished through interactions with kinesin. Based on the newly obtained crystal structures of kinesin-microtubule complexes, we investigate the interactions between kinesin's NBP and microtubule using molecular dynamics simulations. We find that the N-3 motif of NBP has direct interactions with a group of negatively charged residues on α-tubulin through Ser235 and Lys237. These specific long-range interactions induce binding of NBP to microtubule at the right position and assist the formation of the indirect interaction between NBP and microtubule. These interactions between N-3 and microtubule have an important anchor effect for kinesin's motor domain during its rotation with Ser235 as the rotation center, and also play a crucial role in stabilizing the ATP-hydrolysis environment.

Genome-Wide Analysis of mRNA and Long Noncoding RNA Profiles in Chronic Actinic Dermatitis.

Chronic actinic dermatitis (CAD), a photosensitive dermatosis, is characterized by inflammatory lesions, especially on sun-exposed skin. However, its pathogenesis remains unclear. In this study, second-generation RNA sequencing and comprehensive bioinformatics analyses of mRNAs and long noncoding RNAs (lncRNAs) were performed to determine the transcriptome profiles of patients with CAD. A total 6889 annotated lncRNAs, 341 novel lncRNAs, and 65091 mRNAs were identified. Interestingly, patients with CAD and healthy controls showed distinct transcriptome profiles. Indeed, 198 annotated (81.48%) and 45 novel (18.52%) lncRNAs were differentially expressed between the two groups. GO, KEGG, and RGSEA analyses of lncRNAs showed that inflammatory and immune response related pathways played crucial roles in the pathogenetic mechanism of CAD. In addition, we unveiled key differentially expressed lncRNAs, including lncRNA RP11-356I2.4 which plays a role probably by regulating TNFAIP3 and inflammation. qRT-PCR data validated the differentially expressed genes. The newly identified lncRNAs may have potential roles in the development of CAD; these findings lay a solid foundation for subsequent functional exploration of lncRNAs and mRNAs as therapeutic targets for CAD.

Assessment of Corneal Biomechanical Properties by CorVis ST in Patients with Dry Eye and in Healthy Subjects.

Purpose. To investigate corneal biomechanical properties in patients with dry eye and in healthy subjects using Corneal Visualization Scheimpflug Technology (CorVis ST). Methods. Biomechanical parameters were measured using CorVis ST in 28 eyes of 28 patients with dry eye (dry eye group) and 26 normal subjects (control group). The Schirmer I test value, tear film break-up time (TBUT), and corneal staining score (CSS) were recorded for each eye. Biomechanical properties were compared between the two groups and bivariate correlation analysis was used to assess the relationship between biomechanical parameters and dry eye signs. Results. Only one of the ten biomechanical parameters was significantly different between the two groups. Patients in the dry eye group had significantly lower highest concavity time (HC-time) (P = 0.02) than the control group. Correlation analysis showed a significant negative correlation between HC-time and CSS with marginal P value (ρ = -0.39, P = 0.04) in the dry eye group. Conclusions. The corneal biomechanical parameter of HC-time is reduced in dry eyes compared to normal eyes. There was also a very weak but significant negative correlation between HC-time and CSS in the dry eye group, indicating that ocular surface damage can give rise to a more compliant cornea in dry eyes.

Corneal Biomechanical Properties in Myopic Eyes Measured by a Dynamic Scheimpflug Analyzer.

Purpose. To evaluate the corneal biomechanical parameters in myopic and emmetropic eyes using Corneal Visualization Scheimpflug Technology (CorVis ST). Methods. 103 myopic and emmetropic eyes of 103 patients were examined. Corneal biomechanical parameters, axial length, and mean keratometry were measured using CorVis ST, IOL Master, and topography, respectively. Corneal biomechanical properties were compared within four groups. Bivariate correlation analysis was used to assess the relationship between corneal biomechanical parameters and ocular characteristics. Results. Four of ten corneal biomechanical parameters, namely, deformation amplitude (DA), first- and second-applanation time (A1-time, A2-time), and radius at highest concavity (HC radius), were significantly different within the four groups (P < 0.05). In correlation analysis, DA was positively correlated with axial length (r = 0.20, P = 0.04); A2-time was positively correlated with spherical equivalent (SE) (r = 0.24, P = 0.02); HC radius was positively correlated with SE (r = 0.24, P = 0.02) and was negatively correlated with mean keratometry (r = -0.20, P = 0.046) and axial length (r = -0.21, P = 0.03). Conclusions. The corneal refraction-related biomechanical alterations were associated with ocular characteristics. Highly myopic eyes exhibited longer DA and smaller HC radius than do moderately myopic eyes; the eyes with longer axial length tend to have less corneal stiffness and are easier to deform under stress.

[Comparison of corneal nerve regeneration and dry eye condition after conventional LASIK and femtosecond-assisted LASIK].

OBJECTIVE: To compare the regeneration of subbasal epithelial nerve plexus in the central cornea and dry eye condition between patients undergoing conventional LASIK surgery and femtosecond-assisted LASIK surgery. METHODS: It was across-sectional study. Thirty patients (60 eyes) who had LASIK at our hospital from October 2011 to September 2012 were included in this study. Patients were divided into conventional LASIK group and femtosecond-assisted LASIK group based on the method used for corneal flap creation. Subjective and objective dry eye tests were carried out at 1 year after surgery. HRT III confocal microscopy was used to observe the regeneration of subbasal epithelial nerve plexus, and the images were analyzed by ACCMetrics software using quantitative parameters to determine the density and morphology of corneal nerve fibers. The data of corneal nerve fibers and dry eye condition in the two groups undergoing different LASIK procedures was compared using an independent sample t test. RESULTS: During the one-year postoperative follow-up, the Schirmer test result, tear film break-up time value, and ocular surface disease index score in the F-LASIK group [(12.65 +/- 8.73) mm/5min, (7.85 +/- 2.81) s, (7.25 +/- 6.35) points] were not significantly different from that in the C-LASIK group [(6.73 +/- 10.55) mm/ 5 min, (8.77 +/- 3.04) s, (4.46 +/- 5.37) points] (t =1.399, -1.050, -1.613, P > 0.05). Regarding the nerve fiber measurements, which included corneal nerve fiber density, corneal nerve branch density, corneal nerve fiber length, corneal total branch node, corneal nerve fiber width, and corneal nerve fiber tortuosit, there was no statistically significant difference in their results between patients who had femtosecond-assisted LASIK surgery [(16.46 +/- 6.65 )/mm2, (19.27 +/- 9.56)/mm2, (10.88 +/- 4.70) mm/mm2, (65.10 +/- 38.43)/mm2, (4.76 +/- 0.34) microm, (2.30 +/- 0.34) grades] and those who had conventional LASIK surgery [(15.99 +/- 7.14)/mm2, (19.39 +/- 7.07)/mm2, (11.30 +/- 3.17) mm/mm2, (68.43 +/- 34.94)/mm2, (4.73 +/- 0.24) microm, (2.14 +/- 0.34) grades] (t = -0.229, 0.049, 0.365, 0.306, -0.394, -1.629, P > 0.05). CONCLUSION: The difference between conventionalLASIK and femtosecond-assisted LASIK does not significantly affect the dry eye test values and nerve fiber measurements in patients at 1 year after LASIK.

[Effects of central corneal thickness and corneal curvature on measurement of intraocular pressure with Goldmann applanation tonometer and non-contact tonometer].

OBJECTIVE: To investigate the effects of central corneal thickness (CCT) and corneal curvature (CC) on intraocular pressure (IOP) measurements by the Goldmann applanation tonometer (GAT) and the non-contact tonometer (NCT). METHODS: One hundred and twenty patients were recruited from the clinic of Peking Union Medical College Hospital. The CCT was measured by ultrasound pachymetry and the mean radius of CC by using Canon PK-5 refractometer. The IOP of each eye was measured by both GAT and NCT. Linear regression was used to compare the measurements of GAT and NCT; multi regression was used to analyze the relationships between CCT, CC and the measurements of GAT and NCT. Bland-Altman method was used to compare the effect of NCT and GAT on the IOP measurements. RESULTS: The results of the right eyes were reported in this paper. The mean and standard deviation of IOP measured by GAT and NCT was (18.4 + or - 4.0) mm Hg (1 mm Hg = 0.133 kPa) and (17.0 + or - 4.6) mm Hg, respectively, the difference was statistically significant (r = 0.835, P = 0.000). IOP measured using GAT increased by 0.039 mm Hg per microm increase in CCT. IOP measured using NCT increased by 0.064 mm Hg per microm increase in CCT. For an increase of 1 mm of mean corneal curvature there was decrease in IOP of 2.648 mm Hg measured by the GAT and of 3.190 mm Hg measured by the NCT. Compared to the GAT, NCT underestimated at low IOP level and overestimated at higher IOP level. CONCLUSIONS: The IOP measurement obtained with both GAT and NCT varied with CCT and CC. CCT affected IOP measurements by NCT more than that by GAT.

[Analysis of the effectiveness of laser in situ keratomileusis two years after surgery].

OBJECTIVE: To evaluate the effectiveness of laser in situ keratomileusis (LASIK) for myopia after 2 year follow-up. METHODS: LASIK surgery was performed for 95 eyes (49 cases) with refractive dioptres (from -1.00 to -16.50 D), and then followed up for more than 2 years. The preoperative spherical equivalent was -1.00(-)-16.50 (-6.73 +/- 2.02) D. Patients were divided into two groups including group I with mild to moderate myopia (< or = -6.00 D) and Group II with severe myopia (more than -6.00 D). RESULTS: In group I, uncorrected visual acuity more than and equivalent to 1.0 was in 40 eyes (93.02%), more than and equivalent to 0.8 in 43 eyes (100%). In group II, uncorrected visual acuity larger than and same as 1.0 was in 37 eyes (71.15%), larger than and same as 0.8 in 45 eyes (86.54%), larger than and same as 0.5 in 50 eyes (96.15%), and less than 0.5 in 2 eyes (3.85%). The mean spherical equivalent changed from (-4.14 +/- 0.86) D to (-0.04 +/- 0.14) D in group I and from (-9.00 +/- 1.64) D to (-0.08 +/- 0.20) D in group II. Significant difference was seen in these two groups (P < 0.001). The keratometric powers (K) were reduced from (44.31 +/- 0.78) to (40.11 +/- 1.23) and from (45.46 +/- 1.00) to (38.01 +/- 1.73) respectively, which showed significant difference (P < 0.001). CONCLUSION: The effectiveness of LASIK for mild to moderate myopia or severe myopia is promising and safe.