Digital measuring the ocular morphological parameters of guinea pig eye in vivo with Python

AIM

To quantitatively measure ocular morphological parameters of guinea pig with Python technology.

METHODS

Thirty-six eyeballs of eighteen 3-week-old guinea pigs were measured with keratometer and photographed to obtain the horizontal, coronal, and sagittal planes respectively. The corresponding photo pixels-actual length ratio was acquired by a proportional scale. The edge coordinates were identified artificially by ginput function. Circle and conic curve fitting were applied to fit the contour of the eyeball in the sagittal, coronal and horizontal view. The curvature, curvature radius, eccentricity, tilt angle, corneal diameter, and binocular separation angle were calculated according to the geometric principles. Next, the eyeballs were removed, canny edge detection was applied to identify the contour of eyeball in vitro. The results were compared between in vivo and in vitro.

RESULTS

Regarding the corneal curvature and curvature radius on the horizontal and sagittal planes, no significant differences were observed among results in vivo, in vitro, and the keratometer. The horizontal and vertical binocular separation angles were 130.6°±6.39° and 129.8°±9.58° respectively. For the corneal curvature radius and eccentricity in vivo, significant differences were observed between horizontal and vertical planes.

CONCLUSION

The Graphical interface window of Python makes up the deficiency of edge detection, which requires too much definition in Matlab. There are significant differences between guinea pig and human beings, such as exotropic eye position, oblique oval eyeball, and obvious discrepancy of binoculus. This study helps evaluate objectively the ocular morphological parameters of small experimental animals in emmetropization research.

En-bloc transurethral resection vs. conventional transurethral resection for primary non-muscle invasive bladder cancer: A meta-analysis

INTRODUCTION

We performed a meta-analysis to evaluate the effect of en-bloc transurethral resection vs. conventional transurethral resection for primary non-muscle invasive bladder cancer.

METHODS

A systematic literature search up to January 2022 was done and 28 studies included 3714 primary non-muscle invasive bladder cancer subjects at the start of the study; 1870 of them were en-bloc transurethral resection, and 1844 were conventional transurethral resection for primary non-muscle invasive bladder cancer. We calculated the odds-ratio (OR) and mean-difference (MD) with 95% confidence-intervals (CIs) to evaluate the effect of en-bloc transurethral resection compared with conventional transurethral resection for primary non-muscle invasive bladder cancer by the dichotomous or continuous methods with random or fixed-effects models.

RESULTS

En-bloc transurethral resection had significantly lower twenty-four-month recurrence (OR: 0.63; 95%CI: 0.50-0.78; p < 0.001), catheterization-time (MD: -0.66; 95%CI: -1.02-[-0.29]; p < 0.001), length of hospital stay (MD: -0.95; 95%CI: -1.55-[-0.34]; p = 0.002), postoperative bladder irrigation duration (MD: -6.06; 95%CI: -9.45-[-2.67]; p < 0.001), obturator nerve reflex (OR: 0.08; 95%CI: 0.02-0.34; p = 0.03), and bladder perforation (OR: 0.14; 95%CI: 0.06-0.36: p < 0.001) and no significant difference in the 12-month-recurrence (OR: 0.79; 95%CI: 0.61-1.04; p = 0.09), the operation time (MD: 0.67; 95%CI: -1.92 to 3.25; p = 0.61), and urethral stricture (OR: 0.46; 95%CI: 0.14-1.47; p = 0.0.19) compared with conventional transurethral resection for primary non-muscle invasive bladder cancer subjects.

CONCLUSIONS

En-bloc transurethral resection had a significantly lower twenty-four-month recurrence, catheterization time, length of hospital stay, postoperative bladder irrigation duration, obturator nerve reflex, bladder perforation, and no significant difference in the twelve-month recurrence, operation time, and urethral stricture compared with conventional transurethral resection for primary non-muscle invasive bladder cancer subjects. Further studies are required.

Development and Validation of a Simple Nomogram for Predicting Rapid Myopia Progression in Children with Orthokeratology Management

PURPOSE

To develop and validate an ideal nomogram and an online calculator for predicting rapid myopia progression risk in children managed with orthokeratology (ortho-k).

METHODS

Data of children undergoing ortho-k treatment at Shanghai Children's Hospitals between January 2018 and April 2021 were retrospectively assessed. Potential predictors were screened using univariable analyses and a bidirectional stepwise procedure based on Akaike's information criterion. The final model was constructed using multivariable logistic regression and validated using an internal validation cohort. A nomogram and an online calculator were used to present the final model.

RESULTS

In this retrospective study with 1051 eyes of 560 myopia patients, the training cohort included 735 eyes, and the validation cohort included 316 eyes. Among 11 potential predictors of rapid myopia progression considered, the following four variables identified as independent predictive factors were included in the nomogram: age (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.61-0.79), baseline spherical equivalent (OR, 1.53; 95% CI, 1.31-1.79), pupil diameter (OR, 0.56; 95% CI, 0.32-0.97), and horizontal visible iris diameter (OR, 0.57; 95% CI, 0.33-0.97). The mean concordance statistics for the training and validation cohorts were 0.705 (95% CI 0.664-0.747) and 0.707 (95% CI 0.639-0.774), respectively. The online calculator is publicly available (https://hycalculatoronline.shinyapps.io/dynnomapp/).

CONCLUSION

This study developed a simple-to-use nomogram and online calculator that predicted rapid myopia progression risk in children treated with ortho-k, who will likely benefit from early intervention and improved surveillance.

Surgical treatment of Pitt-Hopkins syndrome associated with strabismus and early-onset myopia: Two case reports

BACKGROUND

Pitt-Hopkins syndrome (PTHS; MIM #610954) is a rare genetic neurological disorder. Myopia and strabismus have been reported in approximately 50% of PTHS patients. No studies have reported details about the required surgery for PTHS with strabismus and early-onset myopia. Here, we retrospectively reviewed the surgical management of two patients with PTHS combined with strabismus and/or early-onset myopia.

CASE SUMMARY

A 5-year-old girl presented with congenital esotropia and left eye myopia, and the second girl was a 5-year-old girl who presented with intermittent exotropia. Genetic testing performed on both patients showed a mutation in transcription factor 4, which is a diagnostic marker of PTHS. The first girl underwent bilateral medial rectus recession combined with posterior scleral reinforcement (PSR) in the left eye and the second patient underwent bilateral lateral rectus recession strabismus surgery. We made key innovations in surgical timing and strategy, and the results were satisfactory. The combination of strabismus and PSR surgery is an innovative strategy for patients with both strabismus and early-onset myopia.

CONCLUSION

Early treatment of strabismus and myopia positively influence motor development and should be included in rehabilitation programs for patients with PTHS.

Surgical outcomes and observation in exotropia cerebral palsy children with cortical visual impairment

PURPOSE

Cortical visual impairment (CVI) is the common cause of pediatric visual impairment in cerebral palsy (CP) while exotropia is the most common strabismus associated with CP. We aim to observe the strabismic surgery outcomes in pediatric patients with CP and CVI.

METHOD

Our medical records were collected from pediatric patients treated in our hospital from May 1, 2017 to Jan 1, 2022. With normal intelligence assessment and diagnosis of exotropia in children with CP and CVI, microsurgeries were performed under intravenous combined inhalation anesthesia. The strabismus was examined by the prism test under best vision correction and the contrast sensitivity testing (CST) was measured at five levels of spatial frequencies.

RESULT

A total of 38 exotropia patients with CP and CVI were identified and included for analysis during the study period with age ranged from 5 to 12 years (mean 8.45 years) and mean follow up duration was 8.7 months (6-42 months). After bilateral lateral rectus recession (with/without medial rectus resection or inferior oblique transposition), the exotropia amount of participants were obviously revealed from - 30 ~ - 140 (median, IQR: - 50, 40) prism diopters (PD) preoperatively to 0 ~ - 15 (0, 5) PD postoperatively. Statistically significantly improvements were observed at all levels of spatial frequency on CST postoperatively, especially at high spatial frequency areas (p < 0.05).

CONCLUSION

Our results demonstrated that the effect of strabismus surgery on exotropia in children with CP and CVI were stable and monocular contrast sensitivity post- operation increased significantly at all spatial frequencies levels.

MSC-derived exosomal lncRNA SNHG7 suppresses endothelial-mesenchymal transition and tube formation in diabetic retinopathy via miR-34a-5p/XBP1 axis

AIMS

Diabetic retinopathy (DR) is the most common complication of type 2 diabetes mellitus, which could result in visual impairment. Accumulating studies have shown the implication of long non-coding RNAs (lncRNAs) in the pathogenesis of DR. Our aims are to investigate whether lncRNA SNHG7 plays a role during DR pathogenesis.

MAIN METHODS

Human retinal microvascular endothelial cells (HRMECs) were treated with high glucose (HG) to build cell model. Relative expression of RNAs were examined using qPCR, and western blot or immunofluorescence analysis was adopted to detect the protein expression. Cell viability, migration and angiogenic capacity of HRMECs were estimated through CCK-8, transwell and tube formation experiments, respectively. Dual-luciferase reporter and RNA pull down assays were employed to verify the interplay between miR-34a-5p and SNHG7 or XBP1. Mesenchymal stem cells (MSCs) were identified by examining typical surface makers using flow cytometry and the differentiation abilities via Alizarin red, Oil red O and Alcian blue staining. MSC-derived exosomes were verified by transmission electron microscopy and western blot.

KEY FINDINGS

LncRNA SNHG7 sponged to and negatively regulated miR-34a-5p. SNHG7 overexpression repressed HG induced endothelial-mesenchymal transition (EndMT) and tube formation of HRMECs, while miR-34a-5p overexpression could reverse this effect. miR-34a-5p targeted and negative regulated XBP1. Knockdown of miR-34a-5p repressed HG induced EndMT and tube formation, which were partially blocked by XBP1 inhibition. MSC-derived exosomes could transfer SNHG7 to HRMECs and modulated EndMT and tube formation.

SIGNIFICANCE

The MSC-derived exosomal lncRNA SNHG7 suppresses EndMT and tube formation in HRMECs via miR-34a-5p/XBP1 axis.

Effects of blood pathological changes before TAI on pregnancy of dairy cows with anestrus and estrus

ABSTRACT The objective of this study was to investigate the influence of plasma pathological changes before timed artificial insemination (TAI) on pregnancy of cows. The contents of estrogen (E2), progesterone (P4), glucose (Glu), selenium (Se), brain-derived neurotrophic factor (BDNF), and histamine (HIS) in plasma of 48 Holstein cows were measured before TAI. According to the estrus detection, the cows were divided into estrus (E) and anestrus (A) groups. After pregnancy testing at 28 d after TAI, two groups of E and A were divided into positive pregnancy of E group (EP+), negative pregnancy of E group (EP-), positive pregnancy of A group (AP+), and negative pregnancy of A group (AP-). The contents of E2, P4, Glu, Se, BDNF and hIS significantly differed among the four groups (P<0.01). The ROC analysis was used to determine the risk of negative pregnancy test (-) after TAI was increased when plasma E2 was less than 46.45 pmol/L in cows before TAI. The changes in E2, P4,hIS, Glu, and BDNF in the blood of natural estrus and natural anestrus cows affected the pregnancy after TAI. the level of E2 in plasma may be used to assess the risk of negative pregnancy after TAI.

Small Molecule-Induced Dimerization of Hairpin RNA Interfered with the Dicer Cleavage Reaction

MicroRNAs are potential targets for drug development. Small molecules that can inhibit or promote a specific miRNA's biogenesis would be useful for regulating its target genes. Various types of small molecules have been investigated so far for their potential application in modulating miRNA biogenesis. They bind to the target primary or precursor miRNAs and inhibit the processing of these precursors by Drosha or Dicer. However, the binding site that effectively interferes with the Dicer cleavage reaction is still undetermined. Here we report that our designed small molecule restricted naphthyridine dimer (RND) binds to the hairpin loop of a hairpin RNA and induces its dimerization. This study shows that the binding of the RND to the hairpin loop was not effective in interfering with the Dicer cleavage reaction, but dimerization of the hairpin RNA by RND binding effectively interfered with the Dicer cleavage reaction.

Measuring the Ocular Morphological Parameters of Guinea Pig Eye with Edge Detection and Curve Fitting

AIM

To identify the guinea pig eyeball with edge detection and curve fitting and devise a noncontact technology of measuring ocular morphological parameters of small experimental animal.

METHODS

Thirty-nine eyeballs of guinea pig eyeballs were photographed to obtain the anterior and posterior surface; transverse and sagittal planes after the eyeballs were eviscerated. Next, the eyeball photos were input into digital image analysis software; the corresponding photo pixels-actual length ratio was acquired by a proportional scale. The contour lines of the eyeballs were identified by edge detection technology; conic curve fitting was applied to fit the contour line of the eyeball. The maximum and minimum diameters, the horizontal and vertical diameters, eccentricity, tilt angle, cross-sectional area, equatorial circumference, retrobulbar equatorial maximum length, corneal radius of curvature (CRC) in central region, and the whole cornea were calculated according to the geometric principles. The corneal data of in vitro study were compared with the in vivo results.

RESULTS

The contour line of the selected guinea pig eye was identified correctly by edge detection. There were no significant differences between anterior and posterior surfaces of one eyeball in the maximum diameters, eccentricity, cross-sectional area, equatorial circumference, and tilt angle (P > 0.01). There were significant differences of eccentricity and CRC between central region and the whole cornea (P < 0.01). There were no significant differences between keratometer in vivo and cornea in vitro.

CONCLUSION

It was feasible to measure an experimental animal eye in a noncontact way. Edge detection and curve fitting technology could accurately evaluate the ocular morphological parameters.

[Retinal toxicity study of intravitreal ganciclovir in albino rabbit]

Objective: To elevated the retinal toxicity of intravitreal ganciclovir in albino rabbit eyes. Methods: Experimental study. Twenty-four New Zealand albino rabbits (forty-eight eyes) were divided into four groups by random. Three groups were prepared for ganciclovir experiment, named A, B, C. Each group received intravitreal injection ganciclovir dose at 400 μg/0.05 ml, 2 mg/0.05 ml and 5 mg/0.05 ml respectively. The other group named D served as a control accepted intravitreal injection 0.9% normal saline 0.1 ml. Before and after 1, 2 and 4 weeks, flicker full field electroretina gram (ERG) was recorded. After 1, 2 and 4 weeks light and electron microscopic tests were recorded for further toxicity study. Results: There was significant difference in amplitude of maximal combined response a wave in one week(χ(2)=8.319, P=0.04), and pairwise comparison the 5 mg group (140.50 μV) was significantly lower than the control group (165.00 μV) (χ(2)=-2.830, P=0.028). Maximal combined response b wave in four weeks(χ(2)=-10.626, P=0.014), and pairwise comparison the 5 mg group (261.50 μV) was significantly lower than the control group (398.00 μV) (χ(2)=-2.973, P=0.018). 30 Hz flicker response in one, two and four weeks(χ(2)=17.589, 8.225, 8.997, P=0.001, 0.042, 0.02), and pairwise comparison the 5 mg group (71.3μV, 106.00μV, 63.60μV) was significantly lower than the control group (118.50μV, 129.00μV, 116.50μV) (χ(2)=-4.142, -2.826, -2.713, P=0.000, 0.028, 0.040). There was no histologic retinal toxicity evidence of group 400 μg and control group observed by light microscopy in any stage of the study. Histologic changes of group 2 mg four week later, group 5 mg two and four week later include inner nuclear layer loose arranged, nuclear of ganglia were widened and outer plexiform layer stained less in four week later. By electron microscopic observation, the ultrastructure of retina changed to different degrees and became worse in each experimental group with significant mitochondrial swelling and hydropic changes were seen in the inner segments of photoreceptors, loosely arranged and disordered in the outer segment of photoreceptors four weeks later. Conclusions: The retinal function and morphology were normal in group 400 μg. Group 2 mg and 5 mg had retinal toxicity, and 5 mg was more severe. Therefore, the clinical application of ganciclovir in the treatment of acute retinal necrosis (ARN) should select the minimum effective dose to avoid the occurrence of retinal toxicity. (Chin J Ophthalmol, 2020, 56:279-285).

Ocular findings and strabismus surgery outcomes in Chinese children with Angelman syndrome: Three case reports

RATIONALE

Angelman syndrome (AS) is an uncommon genetic disease characterized as serious retarded mental development and ocular abnormality.

PATIENT CONCERNS

This report aims to present the ophthalmological features, and identify the diagnosis and outcomes of strabismus surgery in AS patients.

DIAGNOSIS

Three children with exotropia were diagnosed with AS based on their typical clinical features.

INTERVENTIONS

All patients underwent multiplex ligation-dependent probe amplification (MLPA) analysis and accepted lateral rectus recession surgery with the assistance of intravenous combined inhalation anesthesia.

OUTCOMES

The maternal heritage deletion of chromosome 15q11.2-q13 was verified in all patients by MLPA. All patients with strabismus could not cooperate during the vision test, and had astigmatism. The strabismus type of AS patients was horizontal exotropia, and no vertical strabismus was found. One of these patients was combined with high myopia. The hypopigmentation on the hair and iris was ubiquitous. However, retina pigmentation was normal. After different degrees of lateral rectus recession, the exotropia was significantly relieved, and the surgical effects were stable postoperatively.

LESSONS

Horizontal exotropia is the major strabismus type. Severe intellectual disability, hyperactivity, and speech impairment are the common characteristics of AS children. Its examination and operation design remains challenging. Thus, repeated examinations and intelligence rehabilitation are essential.

[The relationship between optical coherence tomography performance and visual acuity of acute retinal necrosis]

Objective: To analyze the relationship between optical coherence tomography(OCT) performance and visual acuity of patients with acute retinal necrosis (ARN). Methods: Retrospective analysis was performed on the patients diagnosed with ARN at the ophthalmology department of Peking union hospital during October 2011 and May 2016. Fourteen patients (15 eyes), 9 males and 5 females, whose anterior and posterior inflammation disappeared and the retinal necrosis lesion in the fundus of the eye subsided were included. The mean age was (41.6±12.2) years. All patients underwent careful examinations including best corrected visual acuity (BCVA), slit-lamp microscope, indirect ophthalmoscope, color fundus picture, fundus fluorescein angiography (FFA) and OCT (results of their last consultations). Results: BCVA: 8 eyes were increased, 2 eyes were unchanged and 5 eyes were decreased at the last visit; light perception (LP) 1 eye, finger count (FC) 1 eye, 3 eyes of 0.01 to 0.1, 6 eyes of 0.15 to 0.25. The inflammatory reaction in the anterior segment of 14 eyes disappeared, while the inflammatory reaction of the remaining 1 eye was relieved. The fundus lesions of all 15 eyes disappeared. According to OCT results: five eyes (5/15) exhibited normal macula area, among the 5 eyes, 4 eyes are of 0.15 to 0.25 visual acuity, and 1 eye is of 0.5 visual acuity;macular epiretinal membrane is present in three eyes (3/15), of which the visual acuity is 0.02, 0.25 and 0.3 respectively macula edema is present in three eyes (3/15), among the 3 eyes, 1 eye (visual acuity of 0.01)showed thickening of neurosensory retina, cystoid change of fovea and several fluid dark areas, the other 2 eyes (visual acuity of 0.02 and 0.5 respectively) showed small diffuse fluid dark area in the neurosensory retina;atrophy of neurosensory retina and absence of IS/OS was found in four eyes (4/15), among the 4 eyes, the visual acuity of 3 is below 0.01, and the other 1 eye is of 0.08 visual acuity. Conclusions: The OCT performance of stationary phase of ARN tends to be positively correlated with the visual acuity of patients. The prognosis of visual acuity of the patients whose OCT results showed atrophy of neurosensory retina and absence of IS/OS is poor. (Chin J Ophthalmol, 2018, 54: 369-374).

[Research progress on the diagnosis and treatment of acute retinal necrosis]

Acute retinal necrosis is an uncommon but devastating and potentially blinding ophthalmopathy featured with unfavorable prognosis as the lesions tend to develop rapidly in a circumferential way in few days. Therefore timely diagnosis and early treatment are of great significance. The polymerase chain reaction test on intraocular fluid can improve specificity and sensitivity of the etiological detection for acute retinal necrosis. Etiology results included in the diagnostic criteria is favorable for etiological diagnosis. Current treatment for acute retinal necrosis is generally based on systemic antiviral therapy, and supported by hormone and antithrombotic drugs, while surgical treatment should be considered when the disease progresses. This article reviews the research progress on the diagnosis and treatment of acute retinal necrosis in an effort to improve the diagnosis and treatment performance of acute retinal necrosis. (Chin J Ophthalmol, 2018, 54: 306-311).

[Current research of sympathetic ophthalmia]

Sympathetic ophthalmia (SO) is a rare, bilateral, non-necrotizing, granulomatous uveitis that usually occurs after open ocular injury or intraocular surgery. The pathophysiology is not clearly understood, but generally SO is an immediate hypersensitivity mediated by T lymphocytes which are related to ocular tissue antigens. The main histopathological features are granulation tissues composed of lymphocytes, macrophages and multinucleated giant cells. The clinical manifestations are different from person to person, which might be mild or severe. Although it could be presented with anterior uveitis, intermediate uveitis and posterior uveitis, panuveitis is the most common sign. The ophthalmic examinations, such as fundus fluorescein angiography, optical coherence tomography and B-scan, could be used to observe the patients' conditions and monitor the therapeutic effect. The main treatment of SO is medical therapy with corticosteroids, immunomodulators and biomodulators. Topical drug administration, including intravitreal injection of triamcinolone acetonide and implantation of a fluocinolone acetonide implant, can be considered. There is controversy about whether enucleation or evisceration is more appropriate and when the procedure should be done. The prognosis of SO could be poor. SO is liable to deteriorate and may lead to blindness. This article reviews the etiology, mechanisms, histopathology, clinical characteristics, diagnosis and treatment of SO. (Chin J Ophthalmol, 2017, 53:778-782).

[The ocular manifestations of human immunodeficiency virus and syphilis coinfection]

Objective: To investigate the ocular manifestations of human immunodeficiency virus (HIV) and syphilis coinfection. Methods: A retrospective analysis of the ocular manifestations was carried out in 27 patients (54 eyes) diagnosed as syphilis and HIV coinfection by the Department of Infectious Medicine in Peking Union Medical College Hospital during the years of 2006-2017. The research included 26 males and 1 female, aging from 24 to 76 years old, with a mean age of 40.40±12.94 years old. Ocular anterior segments were examined with slit-lamp microscope. Fundus examinations were conducted with papillary dilation, fundus photography. Results: At the first visit, there were 2 eyes without light perception, 4 eyes with light perception, 1 eye with hand movement, 1 eye with finger counting, 2 eyes with 0.01-0.09 eyesight, 8 eyes with 0.1-0.2 eyesight, 12 eyes with 0.25-0.4 eyesight, 15 eyes with 0.5-0.9 eyesight, 9 eyes with 1.0-1.5 eyesight. Among the 27 patients (54 eyes) coinfected with HIV and syphilis, keratic precipitates were identified in 20 eyes, aqueous flare positive in 20 eyes, float positive in 15 eyes, and iris posterior synechias in 7 eyes. Nineteen eyes were diagnosed as syphilis uveitis, including 2 eyes with syphilis anterior uveitis and 17 eyes with syphilis panuveitis, among which, vitreous inflammatory opacity was observed in all 19 eyes, disk atrophy in 2 eyes, optic edema in 1 eye, vitreous hemorrhage in 1 eye, retinal detachment in 2 eyes, retinal hemorrhage and white vein in 1 eye. In addition, 8 eyes were diagnosed as HIV retinopathy, all manifested as cotton-wool spot. Among the 8 eyes, 4 were diagnosed as cytomegalovirus retinitis, 3 showed retinal yellow-white lesions, and 1 was in late phase which showed retinal pigmentation. The incidence of both HIV and syphilis coinfection patients and male homosexuality population increased. The most common ocular manifestation of HIV and syphilis coinfection was syphilis panuveitis. Six patients first visited the Department of Ophthalmology, and were then diagnosed as HIV and syphilis coinfection. Conclusions: The ocular manifestations of HIV and syphilis coinfection are diversified, which can be manifested as fundus necrotic lesions as well as anterior and posterior inflammatory. For HIV positive patients, syphilis serologic test should be routinely performed. The same, syphilis positive patients should be tested for HIV serum antibodies, in order to improve the diagnosis level of HIV/syphilis coinfection and give timely etiological treatment, which is of vital importance for saving visual acuity. (Chin J Ophthalmol, 2019, 55:267-272).

Myopia induced by flickering light in guinea pig eyes is associated with increased rather than decreased dopamine release

PURPOSE

It is well known that the dopaminergic signaling pathway plays a pivotal role in the control of axial elongation. Much research has shown that retinal dopamine (DA) is decreased in experimental myopia, but the exact alteration in DA quantity underlying the myopia model induced by flickering light (FL) has not yet been fully elucidated. Therefore, in this study, we first attempted to prove the feasibility of the myopia model induced by FL and then to determine whether and how DA and its receptors changed in myopia induced by FL.

METHODS

Forty-five 2-week-old guinea pigs were randomly divided into three groups, as follows: the control group, form-deprivation myopia (FDM) group, and FL-induced myopia (FLM) group. Animals in the control and FDM groups were raised under normal illumination, and the right eyes of the FDM group were covered with semitransparent hemispherical plastic shells serving as eye diffusers. Guinea pigs in the FLM group were raised under illumination with a duty cycle of 50% at a flash rate of 0.5 Hz. The refraction, axial length (AL), and corneal radius of curvature (CRC) were measured using streak retinoscopy, A-scan ultrasonography, and keratometry, respectively, before and after 2, 4, 6, and 8 weeks of treatment. The contents of DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in the retina, vitreous body, and RPE were measured at the end of the 8-week experiment using high-performance liquid chromatography (HPLC). The numbers of retinal D1 DA receptor (D1DR) and D2 DA receptor (D2DR) were evaluated via immunohistofluorescence and western blot assay.

RESULTS

The refraction of the FLM group became more myopic throughout the experimental period, which was mainly indicated by decreased refraction and a longer AL compared with the control group (p<0.05). The contents of DA, DOPAC, and HVA in the retina, vitreous body, and RPE of the FLM group were significantly increased, but decreased in the FDM group, compared with those of the control group (both p<0.05). Like form-deprived eyes, the expressions of retinal D1DR and D2DR in FL eyes were significantly upregulated compared with controls (p<0.05).

CONCLUSIONS

Myopia can be induced by 0.5-Hz FL in guinea pigs at puberty. Contrary to FDM, dopaminergic neuron activity and DA release were significantly elevated in FLM. Like in FDM, the expressions of D1DR and D2DR were upregulated in FLM. Thus, the results of our study may further demonstrate that the DA system is associated with the development of myopia.

Edge detection and mathematic fitting for corneal surface with Matlab software

AIM

To select the optimal edge detection methods to identify the corneal surface, and compare three fitting curve equations with Matlab software.

METHODS

Fifteen subjects were recruited. The corneal images from optical coherence tomography (OCT) were imported into Matlab software. Five edge detection methods (Canny, Log, Prewitt, Roberts, Sobel) were used to identify the corneal surface. Then two manual identifying methods (ginput and getpts) were applied to identify the edge coordinates respectively. The differences among these methods were compared. Binomial curve (y=Ax²+Bx+C), Polynomial curve [p(x)=p1xⁿ+p2x^n-1 +....+pnx+pn+1] and Conic section (Ax²+Bxy+Cy²+Dx+Ey+F=0) were used for curve fitting the corneal surface respectively. The relative merits among three fitting curves were analyzed. Finally, the eccentricity (e) obtained by corneal topography and conic section were compared with paired t-test.

RESULTS

Five edge detection algorithms all had continuous coordinates which indicated the edge of the corneal surface. The ordinates of manual identifying were close to the inside of the actual edges. Binomial curve was greatly affected by tilt angle. Polynomial curve was lack of geometrical properties and unstable. Conic section could calculate the tilted symmetry axis, eccentricity, circle center, etc. There were no significant differences between 'e' values by corneal topography and conic section (t=0.9143, P=0.3760 >0.05).

CONCLUSION

It is feasible to simulate the corneal surface with mathematical curve with Matlab software. Edge detection has better repeatability and higher efficiency. The manual identifying approach is an indispensable complement for detection. Polynomial and conic section are both the alternative methods for corneal curve fitting. Conic curve was the optimal choice based on the specific geometrical properties.

Intraocular pressure with rebound tonometry and effects of topical intraocular pressure reducing medications in guinea pigs

AIM

To investigate the intraocular pressure (IOP) of adult guinea pig eyes with rebound tonometry (RBT), and assess the effects of four distinctive topical IOP reducing medications including Carteolol, Brimonidine, Brinzolamide and Latanoprost.

METHODS

The IOPs of twenty-four 12-week-old guinea pigs (48 eyes) were measured every two hours in one day with RBT as baselines. All the animals were then divided into four groups (Carteolol, Brimonidine, Brinzolamide and Latanaprost groups, n=6). The IOPs were measured and compared to the baseline 1, 2, 3, 5, 7, 9, 15 and 24h after treatment.

RESULTS

The mean baseline IOP of 24 guinea pigs (48 eyes) was 10.3±0.36 mm Hg (6-13 mm Hg) and no binocular significant differences of IOPs were observed (t=1.76, P>0.05). No significant difference of IOP in Carteolol group at each time point was observed before and after treatment (t=1.48, P>0.05). In Brimonidine group, IOP was 2.2±1.9 mm Hg lower than the baseline after one hour (t=3.856, P=0.003) and lasted for one hour. In Brinzolamide group, IOP was 1.4±1.1 mm Hg lower than the baseline after one hour (t=4.53, P=0.001) and lasted for 7h and the IOP declined most at 3h. In Latanaprost group, IOP was 2.1±1.3 mm Hg lower than the baseline after one hour (t=6.11, P=0.001) and lasted for one hour.

CONCLUSION

The IOP of guinea pig eyes is relatively stable compared to human eyes. In four reducing IOP medications, no significant effect of Carteolol is observed. Brinzolamide has the longest duration, while the Brimonidine has the shortest duration and the maximum level of treatment.

[Application of optical coherence tomography angiography in ophthalmology]

Optical coherence tomography angiography (OCTA) is a new technology of angiography in recent years. It has advantages of the optical coherence tomography (OCT), moreover, it can hierarchically observe the vascular morphology of the retina and choroid. By using the pseudo-color, abnormal vascular structure can be distinguished from normal vascular structure of the retina. With the fusion of the OCTA image and the regular OCT image, the structure and blood flow information can be obtained at the same time. This technology provides another method of examination for clinical ophthalmology, especially for the diagnosis of retinal diseases. This review will analyze and summarize the operating principle of OCTA, its application in ophthalmology, as well as its advantages and limitations. (Chin J Ophthalmol, 2017, 53: 65-72).

CT perfusion with acetazolamide challenge in C6 gliomas and angiogenesis

Background

This study was performed to investigate the correlation between CT perfusion with acetazolamide challenge and angiogenesis in C6 gliomas.

Methods

Thirty-two male Sprague-Dawley rats were evaluated. The rats were divided randomly to four groups: eight rats with orthotopically implanted C6 gliomas at 10-days old (Group A), eight rats with gliomas at 14-days old (Group B), eight rats with gliomas at 18-days old (Group C), eight rats with orthotopically injected normal saline served as controls. CT perfusion was performed before and after administration of acetazolamide. Changes in perfusion parameters due to acetazolamide administration were calculated and analyzed.

Results

Elevated carbon dioxide partial pressure and decreased pH were found in all 32 rats post acetazolamide challenge (P<0.01). Cerebral blood flow_{pre-challenge} was increased in group C (95.0±2.5 ml/100g/min), as compared to group B (80.1±11.3 ml/100g/min) and group A (63.1±2.1 ml/100g/min). Cerebral blood flow percentage changes were detected with a reduction in group C (54.2±4.8%) as compared to controls (111.3±22.2%). Cerebral blood volume _{pre-challenge} was increased in group C (50.8±1.7ml/100g), as compared to group B (45.7±1.9 ml/100g) and group A (38.2±0.8 ml/100g). Cerebral blood volume percentage changes were decreased in group C (23.5±4.6%) as compared to controls (113.5±30.4%). Angiogenesis ratio = [(CD105-MVD) / (FVIII-MVD)] ×100%. Positive correlations were observed between CD105-microvessel density, angiogenesis ratio, vascular endothelial growth factor, proliferation marker and cerebral blood flow_{pre-challenge}, cerebral blood volume _{pre-challenge}. Negative correlations were observed between CD105-microvessel density and cerebral blood flow percentage changes (P<0.01, correlation coefficient r=-0.788), cerebral blood volume percentage changes (P<0.01, r=-0.703). Negative correlations were observed between angiogenesis ratio, vascular endothelial growth factor, proliferation marker and cerebral blood flow percentage changes, cerebral blood volume percentage changes.

Conclusion

Our findings suggest that CT perfusion with challenge can provide new insight into non-invasive assessment of rat C6 glioma angiogenesis.

Bovine hepatic differential gene expression in response to perennial ryegrass staggers

>‘Perennial ryegrass staggers’ is a neurological condition characterised by muscular tremors and ataxia in livestock that ingest the indole diterpene lolitrem B from endophyte-infected perennial ryegrass. While the neurotoxic mechanism of action of ryegrass staggers has been defined, little is known about metabolic and other molecular processes that lolitrem B may affect in livestock. The objective of this study was to characterise differential gene expression in the liver of animals fed lolitrem B-containing feed over an extended period of time. Eighteen steers were fed one of three rations (n=6/group) containing lolitrem B (247, 1,554 or 2,256 μg/kg (dry matter basis)) over 64 days in a double-blind study. Microarray and confirmatory qPCR were performed to evaluate the hepatic gene expression profile from biopsies taken on days 0 and 64. Widespread perturbation of gene expression was observed in all groups receiving lolitrem B, with a total of 152 differential genes identified (false discovery rate ≤0.05). This suggests that chronic exposure to lolitrem B, even at levels below the current threshold of toxicity (2,000 μg/kg lolitrem B), can perturb many genes, biological processes and pathways. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses indicated that many of these genes were categorised under lipid/steroid biosynthesis/metabolism and oxidation-reduction. Specifically, genes involved in the biosynthesis pathway of ceramide, a sphingolipid molecule (ACSS2, LASS6 and SCD) and changes in neurosignaling through alteration of nitric oxide synthase activity (ARG1 and GPX4) were up-regulated. Future work should focus on the overall balance between ceramide and its metabolites and antioxidants/oxidants in a variety of body matrices in animals with perennial ryegrass staggers, to determine how these compounds contribute to the overall etiology of this disease.

Activity of a group B oncolytic adenovirus (ColoAd1) in whole human blood

Intravenous (i.v.) delivery of therapeutic viruses to human patients exposes virus particles to the potentially neutralising environment of the human bloodstream, where many components of the innate and adaptive immune system provide a formidable barrier to virus infection of target cells. Here we assess the haemocompatibility of ColoAd1, an oncolytic adenovirus currently undergoing clinical assessment for treatment of disseminated cancer by i.v. delivery. Compared with the commonly used serotype Ad5, ColoAd1 (which has a capsid derived from Ad11p) showed only minor inhibition of oncolytic activity by pooled human serum or washed human blood cells, with the amount of ColoAd1 required to kill cancer cells in vitro (the IC50) increasing <10-fold. However, some virus-blood interactions are concentration- and context-dependent, requiring study in whole, undiluted, human blood. ColoAd1 showed <50-fold increases in the IC50 in whole blood from most donors, whereas the activity of Ad5 was ablated. Extrapolating these findings to the clinical situation indicates that ColoAd1 would 'breakthrough' neutralisation in some patients receiving as few as 10(10) ColoAd1 particles i.v., and in most patients receiving doses of 10(12) or above, well within the achievable dose range.

Electrolytic partitioning of uranium and plutonium based on a new type of electrolytic mixer-settler

The design of a new type of electroreduction mixer-settler for the partitioning of uranium and plutonium during the Purex process, which is featured with E-shaped cathodes and U-shaped anodes in settling chamber, is described and the operational results achieved using this equipment are presented. The results show that this new type of mixer-settler has excellent separation performances. The flow rate of organic feed solution is 3 mL/min and the flow ratio of feed solution (1BF) to aqueous back extraction stream (1BX) and to organic wash stream (1BS) is 4/1/1. For an organic feed of 84 g/L uranium and 1.40 ⁓ 2.64 g/L plutonium, both the separation factor of plutonium from uranium and that of uranium from plutonium are apparently higher than 104

The effect of various levels of stroboscopic illumination on the growth of guinea pig eyes

BACKGROUND

The aim was to investigate various levels of stroboscopic illumination effect on the growth of guinea pig eyes.

METHODS

Thirty-six two-week-old guinea pigs were randomised to one of three treatment groups (n = 12 for each). Two stroboscopic-reared groups were raised with a duty diurnal cycle of 50 per cent at a flash rate of 0.5 Hz. Illumination intensity varied between zero-to-250 lux or zero-to-500 lux during each cycle in each group, respectively. The third control group was exposed to 250 lux illumination. Refraction and biometric measurements were taken for each animal prior to and after two, four, six and eight weeks of treatment. Finally, retinal microstructure was examined.

RESULTS

There was significant correlation between refractive errors and axial elongation. After eight weeks of treatment, illumination with flickering light 0-250 lux caused a larger myopic shift with increased axial length than illumination of continuous 250 lux. Stroboscopic illumination with zero-to-500 lux caused a further myopic shift and longer axial length than stroboscopic illumination with zero-to-250 lux. In animals raised in flickering light of zero-to-250 lux or zero-to-500 lux for eight weeks, the outer segment disc membranes in photoreceptor layers were found deformed and detached.

CONCLUSION

Chronic exposure to low-frequency temporally modulated illumination-induced histological damage in the retina and induced exaggerated axial length elongation.

Effects of chronic exposure to 0.5 Hz and 5 Hz flickering illumination on the eye growth of guinea pigs

AIMS

To investigate the effect of prolonged flickering illumination exposure on the growth of the guinea pig eye.

METHODS

Thirty-six 2-week-old guinea pigs were randomized to one of the three treatment groups (n = 12 for each). Two strobe-reared groups were raised with a duty diurnal cycle of 50 % at a flash rate of 0.5 Hz and 5 Hz respectively. Illumination intensity varied between the minimum-maximum light levels of 0-600 lux during each cycle. The control group was exposed to steady 300 lux illumination. All animals underwent refraction and biometric measurements prior to and after 2, 4, 6, 8, 10 and 12 weeks of treatment. Finally, flash electroretinograms were compared, and retinal microstructures were examined.

RESULTS

There was a significant correlation between refractive errors and axial eye elongation, with myopia increasing between 1.5 and 3.4 D per mm eye elongation. After 12 weeks of treatment, the animals raised in 0.5 Hz flickering light were 5.5 ± 0.4 D more myopic than the group raised in continuous illumination, followed by the group raised at 5 Hz flicker light which was about 2.2 ± 1.3 D more myopic. In animals raised in flickering light of 5 or 0.5 Hz for 12 weeks, the implicit time of the a-wave was delayed by 4 and 8.5 ms, respectively. At this time, the outer segment disc membranes were found deformed and detached.

CONCLUSION

Chronic exposure to 0.5 and 5 Hz temporally modulated illumination induces electrophysiological and histological changes in retinal activities that alter the emmetropization of the guinea pig eye.

Myopia induced by flickering light in guinea pigs: a detailed assessment on susceptibility of different frequencies

AIM

To investigate the effectiveness and feasibility of inducing myopia in guinea pigs by flickering light (FL) stimulation with different frequencies.

METHODS

Seventy 2-week-old guinea pigs were randomly assigned to six groups: five FL groups and a control group (n=12 for each). Animals in the five FL groups were raised under 500lx illumination with a duty diurnal cycle of 50% at a flash rate of 5, 1, 0.5, 0.25 and 0.1Hz respectively. Those in the control group were reared under steady 250lx illumination. Refraction, axial length, and radius of curvature were measured before and at 2, 4, 6, 8, 10 and 12 weeks after treatment. At week 12, the eyeballs were taken out and three ocular dimensions and dry weight of sclera were measured.

RESULTS

A myopic shift and axial eye length increase developed in the five FL groups. Stimulation at 0.5Hz caused greater changes in myopic shift, axial elongation, eyeball dimension, and dry weight of sclera than stimulation at other frequencies. Compared with controls, eyes in 0.5Hz group were approximately -5.5±1.5D more myopic with increase in horizontal, vertical, axial dimensions by 0.89±0.3mm, 0.69±0.2mm, 1.12±0.2mm respectively and with increase in dry weight of sclera by 0.44mg.

CONCLUSION

Chronic exposure to periodic illumination at temporal frequency is attended by development of excessive ocular enlargement and myopic refractive error. Emmetropization could be disrupted differently by frequency alteration.

[The progress of fixation eye movement research]

When eyeball fixes targets, it will produce one frequent and regular movement which is difficult to detect. Such movements is called fixation eye motion. This motion can be further divided into drift, tremor and microsaccades. In recent years, research in this field is strikingly increasing. Due to the significant role on the control of fixation positron, maintaining continuous sense of perception, keeping bistable condition, clear vision, spatial orientation and attention, research in this field is maybe a worthwhile myopia research direction.

Comparison between acetazolamide challenge and 10% carbon dioxide challenge perfusion CT in rat C6 glioma

RATIONALE AND OBJECTIVES

The aim of this study was to investigate the effect of perfusion computed tomography (PCT) with acetazolamide (ACZ) challenge and compare it to 10% carbon dioxide (CO(2)) challenge in rat C6 glioma.

MATERIALS AND METHODS

PCT was performed on 32 rats, including 20 with orthotopically implanted C6 gliomas and 12 serving as controls. Ten rats with gliomas and six normal rats underwent PCT with ACZ challenge. The other 10 rats with gliomas and six normal rats underwent PCT with 10% CO(2) challenge. The raw data were processed using Philips computed tomographic brain perfusion software. Perfusion parameters before and after the challenge were recorded. Percentage changes due to ACZ administration and 10% CO(2) challenge were calculated. Pearson's correlation coefficients were used to investigate relationships between percentage changes in perfusion parameters and vascular endothelial growth factor and microvessel density.

RESULTS

In C6 gliomas, percentage change in cerebral blood flow was significantly different between ACZ (72.73%) and 10% CO(2) (28.47%) challenge (P < .01). Percentage change in cerebral blood volume was 37.85% with ACZ and 24.69% with 10% CO(2) challenge (P = .02). In controls, percentage change in cerebral blood flow was significantly different between ACZ (117.42%) and 10% CO(2) (65.86%) challenge (P < .01). For percentage change in cerebral blood volume, there was no significant difference between ACZ (107.51%) and 10% CO(2) (92.95%) challenge. Significant correlations were observed among percentage changes in vascular endothelial growth factor, microvessel density, and cerebral blood volume (P < .01). Percentage change in cerebral blood flow correlated well with vascular endothelial growth factor.

CONCLUSIONS

The results of this study indicate that PCT with ACZ challenge is a more reliable technique compared to 10% CO(2) challenge for the quantitative evaluation of microcirculation in gliomas.

Exact trait-model-free tests for linkage detection in pedigrees

A number of trait-model-free tests have been proposed for linkage detection between a genomic region and a trait. These tests involve testing the dependence in segregation between a trait and marker alleles by assigning a score to every possible identity-by-descent configuration of the pedigree members without modeling the trait, and then averaging the scores over all such configurations compatible with the observed marker genotypes and genealogical relationship of the pedigree members. In this paper we propose a permutation test as an alternative to the existing exact trait-model-free tests for linkage detection. The proposed test is computationally efficient and is applicable on complex multigeneration pedigree structures. In this paper, we have compared the performance of the permutation test with two other exact trait-model-free tests for linkage detection on simulated datasets. We have demonstrated that the proposed permutation test is fully robust against mispecification of marker allele frequencies and has very good power for linkage detection. The permutation test is implemented in the program lm_ibdtests within the framework of MORGAN 2.8 (http://www.stat.washington.edu/thompson/Genepi/MORGAN/Morgan.shtml).

[Relationship between pterygium onset and ultraviolet rays exposure time]

OBJECTIVE

To investigate the dose-effect relationship between the radiation of ultraviolet ray and the onset of pterygium quantitatively.

METHODS

Interrogation was conducted to 95 patients with pterygium in Yacheng district, Sanya City, Hainan Province, 37 males and 58 females, aged 55.7 +/- 13.8 (20 - 80), and 95 local volunteers in 1:1 pairs matched in age, sex, race, and similar habits of wearing glasses and caps (control group). Both the pterygium group and control group were re-divided into three sub-groups: youth (aged < or = 40), middle-aged (aged 41 - 60), and elderly (aged > 60). The time of exposing to ultraviolet ray was calculated. Photo of the pterygium was taken. The length of the pterygium invading into cornea was measured.

RESULTS

The ultraviolet ray exposure time of the youth subgroup, pterygium group, was 35,637 +/- 13,587 hours, significantly higher than that of the youth subgroup, control group (26,188 +/- 17,423 hours, t = 3.352, P = 0.006). The ultraviolet ray exposure time of the middle-aged subgroup, pterygium group, was 73,412 +/- 23,082 hours, significantly higher than that of the middle-aged subgroup, control group (63,368 +/- 25,091 hours, t = 2.322, P = 0.024). However, there was no significant difference in the ultraviolet ray exposure time between the elderly subgroups of both groups. The length of the pterygium invading into cornea was positively correlated with the ultraviolet ray exposure time (r = 0.361, P < 0.05), and the length showed a trend of increased with aging.

CONCLUSION

There is a certain dose-effect correlation between ultraviolet ray exposure and the etiology of pterygium.

Cloning of the KcURA3 gene and development of a transformation system for Kluyveromyces cicerisporus

KcURA3 was cloned from Kluyveromyces cicerisporus CBS4857 by complementation of the ura3 mutation in Saccharomyces cerevisiae. KcURA3 encodes a 267-amino-acid protein with 80% sequence identity to that of S. cerevisiae. An ura3 mutant strain from K. cicerisporus CBS4857, named Y179U, was obtained by selection on 5-fluoroorotic acid plates. Sequence analysis of this mutated gene revealed that it contained a point mutation at nucleotide position +277. Two vectors, pUK1 and pUKD, bearing KcURA3 were constructed. Either the lithium acetate method or electroporation could be used to transform pUK1 and pUKD intoY179U. The transformation efficiency using electroporation was higher than that using the lithium acetate method.

[Treatment of neovascular glaucoma by anterior retinal cryotherapy and trabeculectomy]

OBJECTIVE

To investigate the efficacy of anterior retinal cryotherapy (ARC) for treatment of neovascular glaucoma (NVG).

METHODS

12 eyes (11 patients) with open angle NVG were treated by ARC only, 22 eyes (22 patients) with closed angle NVG were treated by ARC combined with trabeculectomy, and 32 eyes (31 patients) with closed angle NVG were treated by either ARC or cyclocryotherapy as controls. The follow-up period were 6-26 months.

RESULTS

Iris new vessels (INV) regressed or disappeared with normal intraocular pressure (IOP) in 92% (11/12) of the eyes with open angle NVG treated simply by ARC. In comparison with closed angle NVG treated by the same method, there was a significant difference in IOP (P < 0.05). The combination of ARC and trabeculectomy showed markedly better results than either ARC or cyclocryotherapy for treatment of closed angle NVG (P < 0.01). In the eyes with closed angle NVG, INV regressed or disappeared with normal IOP in 86% (19/22), 90% (18/20) achieved a marked relief from pain and the visual acuity was better or unchanged in 67% (8/12) that was significantly different from the eyes treated by cyclocryotherapy (P < 0.05).

CONCLUSION

The results indicate that ARC is suitable for treatment of NVG at early stage, and ARC combined with trabeculectomy, at later stage.

National epidemiological survey of blindness and low vision in China

According to the National Sample Survey of Blindness and Low Vision, the prevalence of blindness in China was 0.43%, resulting chiefly from cataract (41.06%), corneal diseases (15.38%), trachoma (10.87%), and glaucoma (8.80%); and the prevalence of low vision in China was 0.58%, of which the main causes were cataract (49.83%), ametropia/amblyopia (14.98%), trachoma (9.55%), corneal diseases (8.48%), chorioretinal diseases (6.27%), etc. Among children under 14 years of age, the leading cause of blindness and low vision was heredity (48.46%). Among elderly of 60 years and over, the leading cause of blindness and low vision was cataract (73.13%).