Keep Eyes on COVID-19: Ophthalmic Symptoms and Potential Transmission of SARS-CoV-2 through the Oculus.

In December 2019, a new coronavirus disease 2019 (COVID-19) emerged and rapidly spread globally, posing a worldwide health emergency. The pathogen causing this pandemic was identified as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). It is well known that SARS-CoV-2 transmits via respiratory droplets and close contact with infected individuals or contaminated items. In addition to these two major transmission routes, other modes of transmission have not been confirmed. Considering that some COVID-19 patients have presented with ocular discomforts and positive SARS-CoV-2 RNA in ocular surfaces, as well as the discovery of the SARS-CoV-2 receptors, angiotensin-converting enzyme 2, and transmembrane protease, serine 2, in the oculus, the ocular surface is now thought to be a possible alternative route of SARS-CoV-2 transmission and a replication site. This review summarizes the evidence connecting COVID-19 with ocular tissues, ocular symptoms during SARS-CoV-2 infection, the potential role of the conjunctiva in SARS-CoV-2 transmission, and the physiopathological mechanisms. Appropriate precautions in ophthalmology departments, including innovative complete and effective patient management plans, protective personal equipment, hand hygiene, and strict personal distance intervals, are essential to effectively minimize the spread of SARS-CoV-2 and control the pandemic.

Stool vs. Serum Hepatitis B Virus DNA in Patients with Chronic Hepatitis B.

BACKGROUND Serum hepatitis B virus (HBV) DNA and hepatitis B e antigen (HBeAg) liver function in patients with chronic hepatitis B (CHB) are significantly associated. A comparison of clinical significance of fecal HBV DNA and serum HBV DNA has not yet been reported. MATERIAL AND METHODS Stool and serum samples were collected from 66 patients with CHB. Fecal HBV DNA, serum HBV DNA, and intestinal microbiota DNA were detected by real-time quantitative fluorescence polymerase chain reaction (PCR). Liver function and HBeAg were analyzed. RESULTS The stool and serum HBV DNA were positively correlated (r=0.57, P=0.001). Fecal HBV DNA was higher in the HBeAg-positive group than in the HBeAg-negative group (P=0.02). Fecal HBV DNA was negatively correlated with alkaline phosphatase (ALP) (r=-0.41, P=0.001) and TBIL (r=-0.29, P=0.02), and was positively correlated with Enterococcus (r=0.38, P=0.002). Serum HBV DNA was negatively correlated with alanine aminotransferase (ALT) (r=-0.30,P=0.02), aminotransferase (AST) (r=-0.26, P=0.049), and Lactobacillus (r=-0.31, P=0.01). CONCLUSIONS These observations suggest that fecal HBV DNA and serum HBV DNA in patients with CHB have different effects. Fecal HBV DNA might be associated with changes in Enterococcus concentrations, but serum HBV DNA is not.

Susceptibility of Stenotrophomonas maltophilia clinical strains in China to antimicrobial combinations.

We aimed to investigate the activity levels of several combinations of antimicrobials against Stenotrophomonas maltophilia. In this study, the antimicrobial susceptibility of S. maltophilia clinical isolates was determined, and the synergistic activity of three pairs of antimicrobial combinations was evaluated by the fractional inhibitory concentration index (FICI). The antimicrobial susceptibility in vitro against 83 S. maltophilia strains was greater for minocycline (80·7%) than for trimethoprim-sulfamethoxazole (51·8%), and levofloxacin (50·6%). The rate of resistance was highest for ticarcillin-clavulanate and ceftazidime (63·8%) and resistance to trimethoprim-sulfamethoxazole (TMP-SMX) was 48·2%. All three combinations were tested against susceptible isolates. Two of the combinations, TMP-SMX+ceftazidime and levofloxacin+ceftazidime were more effective than the combination of TMP-SMX+levofloxacin. We recommend acquiring more clinical data in order to explore combination therapy, which is a promising treatment of S. maltophilia infections.

[The analysis of Leber's hereditary optic neuropathy associated with mitochondrial tRNAAla C5601T mutation in seven Han Chinese families].

We reported here the clinical, genetic, and molecular characterization of Leber's hereditary optic neuropathy (LHON) with C5601T mutation in seven Chinese families. The ophthalmologic examinations of seven Chinese families who were clinically diagnosed LHON were conducted. Strikingly, these families exhibited very low penetrance of visual impairment, and the penetrance was 9.5%, 14.3%, 4.5%, 8.3%, 10.0%, 22.2% and 25.0%. Meanwhile, entire mitochondrial genome of seven probands was amplified by PCR using 24 pairs of oligonucleotide primers with overlapping fragments. Molecular analysis of mitochondrial DNA (mtDNA) in these pedigrees revealed the absence of three common LHON associated G11778A, G3460A and T14484C mutations but the presence of homoplastic LHON associated tRNAAla C5601T mutation in probands and other matrilineal relatives. These mtDNA polymorphism sites belongs to the Asian haplogroups G2, G2a1, G2a1, G2, G2b, G2a1 and G2. By analyzing mitochondrial genome, seven LHON families all carry the C5601T mutation. The C5601T mutation occurs at the highly conserved nucleotide (conventional position 59) of tRNAAla, thereby contributing to the structural formation and stabilization of functional tRNAs and leading to mitochondrial dysfunction involved in visual impairment. The incomplete penetrance of visual loss in these seven Chinese pedigrees strongly indicates that the tRNAAla C5601T mutation was itself insufficient to produce a clinical phenotype. The lack of functional mtDNA variants in these pedigrees ruled out the role of mitochondrial background in the phenotypic expression of visual loss. Therefore, nuclear backgrounds and environmental factors seem to be modifying factors for the phenotypic manifestation of the tRNAAla C5601T mutation in the seven Chinese families.

[A clinical study of Leber hereditary optic neuropathy].

OBJECTIVE: To investigate the clinical characteristics of Leber hereditary optic neurology (LHON) patients with different primary site mutation. METHODS: Four hundred and fourteen patients with optic neuropathy were divided into three groups: clinically diagnosed LHON group (group A), probable LHON group (group B), optic neuropathy of unknown reason group (group C). Visual acuity (VA), colour vision, Intraocular pressure (IOP), virtual field and visual evoked potential (VEP) were tested for all the patients. Some (64 cases) had optical coherence tomography (OCT) measurement. Mutations of mtDNA were detected for all the groups, and clinical analysis were carried out emphatically in the patients with the 11778 mutation confirmed by gene assessment. T paired test was used to evaluate two group patients of different Mitochondrial DNA mutation. RESULTS: Gene mutations were found in 215 of the 414 patients (52%). Approximately 93% (199/255) of the patients were caused by the common primary mutations (11778, 14484, 3460 mutation), in which 100% mutation (106/106) in group A, 65% (91/139) in group B, and 11% (18/169) in group C. No cases were diagnosed with confirmed LHON in the patients with unilateral optic neuropathy. Fundus examination in 334 eyes of 167 cases showed pseudo papilledema (54 eyes), normal (67 eyes), pale disc or pale on the temporal side of the optic disc (213 eyes). On the basis data of OCT from 64 patients and 84 normal person, RNFL was found thickening at the early stage and thinning gradually at the later stage in the LHON patients. But, the RNFL thickness of patients with 1-2 years history was not significantly different from the patients with over 2 years history(P = 0.051), and there was no difference among the patients with different mitochondrial DNA mutations. The initial mean VA of patients with the 14484 mutation and 11778 mutation were 3.6 ± 0.65, 3.75 ± 0.54 (t = 0.536, P > 0.05), but the follow-up VA were 4.29 ± 0.55 (t = 4.034, P < 0.001) and 3.93 ± 0.49 respectively (t = 1.857, P > 0.05). CONCLUSIONS: The symptoms and fundus manifestation were similar in the LHOH patients with different primary site mutation. Gene mutation analysis is helpful to assess the prognosis of visual acuity.

[The mitochondrial tRNA(Thr) A15951G mutation may be associated with Leber's hereditary optic neuropathy in two Chinese families].

OBJECTIVE: To explore clinical, genetic and molecular features of two Chinese Han families with Leber's hereditary optic neuropathy (LHON). METHODS: Ophthalmologic examinations revealed variable severity and age-at-onset of visual loss among probands and other matrilineal relatives of both families. The families exhibited extremely low penetrance of visual impairment. The entire mitochondrial genome of two probands was amplified by PCR in 24 overlapping fragments using sets of oligonucleotide primers. RESULTS: Sequence analysis of complete mitochondrial genome in the pedigrees excluded three common LHON associated mutations G11778A, G3460A and T14484C, but revealed the presence of a known homoplasmic tRNA(Thr) A15951G mutation. It also showed distinct sets of mtDNA polymorphisms belonging to Eastern Asian haplogroup D4b1. The A15951G mutation is located at the extremely conserved nucleotide (conventional position 71) of tRNA(Thr). Thus, this mutation may alter the structure and stability of mitochondrial tRNA(Thr), thereby leading to a failure in the tRNA metabolism and mitochondrial dysfunction, causing visual impairment. CONCLUSION: The results suggested that the A15951G mutation might be involved in the pathogenesis of Leber's hereditary optic neuropathy in the two families.

[The mitochondrial ND5 T12338C mutation may be associated with Leber's hereditary optic neuropathy in two Chinese families].

Leber's hereditary optic neuropathy (LHON) associated with mitochondrial DNA mutation is a maternally inherited eye disease. We reported here the clinical, genetic and molecular characterization of two Han Chinese families with Leber's hereditary optic neuropathy. Ophthalmologic examinations revealed that the variable severity and age-of-onset in visual impairment among probands and other matrilineal relatives of these families. Strikingly, there were extremely low penetrances of visual impairment in these families. Sequence analysis of complete mitochondrial genomes in these pedigrees identified the homoplasmic ND4 G11696A and ND5 T12338C mutation and distinct sets of polymorphism belonging to haplogroups F2. It is well known that mitochondrial DNA ND4 G11696A is associated with LHON. The ND5 T12338C mutation resulted in replacement of the first amino acid, translation-initiating methionine with a threonine, and shortening two amino acids of ND5. This mutation also locates in two nucleotides adjacent to the 3' end of the tRNALeu(Cun). Thus, this mutation may alter structural formation and stabilization of functional tRNA, thereby leading to a failure in protein synthesis and mitochondrial dysfunction involved in visual impairment. Therefore, the ND4 G11696A and ND5 T12338C mutation is likely associated with LHON in these two Chinese families. But these families exhibited extremely low penetrances of visual impairment. It suggests that other factors, such as nuclear modifier gene(s) or environmental factor(s), may play a role in the phenotypic expression of the LHON-associated ND4 G11696A and ND5 T12338C mutation.

[Measurement of grating acuity in guinea pigs by a customized automated optomotor device].

OBJECTIVE: The guinea pig becomes an important model for studies on myopia, but little is known about its visual performance. In this study, grating acuity was measured using a custom-built automated device to track optomotor responses. METHODS: To record head nystagmus, guinea pigs were individually placed in the center of a rotating drum of 130 cm diameter. The drum was covered inside with square wave gratings of adjustable fundamental spatial frequencies and contrast. The turning movements of the head were tracked using custom-written video software that detected two little white spots painted on a small black piece of cardboard that was attached to the guinea pig's head. Angular head speed was determined from the positions of the two white spots with respect to each other over time, and the ratio of angular head speed to drum speed was determined (the "gain"). In 11 guinea pigs of the same age, but with different refractive states (+9.7 to -15.0 D), responses to spatial frequencies of 0.6 and 2.4 cyc/deg were tested. Furthermore, 17 guinea pigs were tested which had similar refractive states but were different in age (1 to 3 months old). Finally, the effects of different grating contrasts were studied (25%, 50% and 100% contrast respectively) and the effects of different stripe luminances (10, 30, and 350 cd/m(2) respectively). RESULTS: The optomotor response could be used to measure vision in one eye only even if both eyes opened. The optomotor gain was affected by refractive error. Younger animals (one month old) had lower optomotor gain than older ones (0.61 ± 0.2 in one-month, 0.77 ± 0.13 in two-month and 0.80 ± 0.11 in three-month old). For a spatial frequency of 0.6 cyc/deg, the effects of stripe contrast were tested in two months old guinea pigs. At an average stripe luminance of 30 cd/m(2), the optomotor gain dropped from 0.95 ± 0.20 at maximal contrast, to 0.94 ± 0.16 at 50% contrast, and 0.70 ± 0.10 at 25% contrast. At three different luminances, gains were 0.81 ± 0.25 (10 cd/m(2)), 0.95 ± 0.20 (30 cd/m(2)), and 0.80 ± 0.09 (350 cd/m(2)), measured with gratings of 100% contrast, respectively. CONCLUSIONS: Myopic guinea pigs have reduced grating acuity compared to hyperopic ones. The optomotor gain increases with age. For a given grating contrast, the highest optomotor gains are obtained at the highest luminance of 30 cd/m(2). In summary, spatial vision in guinea pig declines with the magnitude of myopia, and increases with luminance and age.

[Refractive and biometric changes in adolescent guinea pig eyes in development and recover stages of form-deprivation myopia].

OBJECTIVE: To investigate changes in refraction and vitreous length during form-deprivation and visual re-exposure in guinea pig eyes. METHODS: It was an experimental study. Ninety-six guinea pigs with age of three weeks were randomly divided into form-deprivation and normal control groups (n = 48 in each group). The form-deprivation group was further divided into 4 subgroups (n = 12 in each subgroup) which underwent monocular form-deprivation for 1, 2, 4, and 6 weeks, respectively. At the end of each time point, the form-deprived eyes in all animals were visually re-exposed and followed for 3 (n = 6) and 7 days (n = 6). The control group was also divided into four subgroups (n = 12 in each subgroup) to match the time-points of the form-deprivation group. During form-deprivation and recovery, vitreous length and refraction in each group was measured and compared. RESULTS: There was significant difference in vitreous length (F = 6.108, 28.222, 19.195) and refraction (F = 12.504, 15.003, 6.829) when compared deprived eyes with contralateral eyes 2, 4, or 6 weeks after form-deprivation (P < 0.05). Difference in refraction between deprived eyes and contralateral eyes was -2.36 D, -3.64 D and -3.68 D at 2, 4, 6 week, respectively. Difference in vitreous length was 0.08 mm, 0.19 mm and 0.22 mm. During visual re-exposure, form-deprived eyes changed into hyperopia as compared with contralateral eyes. At day 3 point, there was no significant difference in refraction and vitreous length between form deprived eyes and contralateral eyes in 1 week and 2 weeks groups (F = 0.032, 0.280; P > 0.05). After 7 days recovery, vitreous length and refraction in deprived eyes almost backed to level of contralateral eyes in 1 and 2 weeks groups. At day 3 point, there was significant difference of refraction and vitreous length between form-deprived eyes and contralateral eyes in 4 weeks group and 6 weeks group. After 7 days recovery, there was significant difference in vitreous length for 4 weeks group and there was significant difference in both refraction and vitreous length for 6 weeks group (F = 4.108, 6.317; P < 0.05). CONCLUSION: Form-deprivation causes myopic changes in deprived eyes, during visual re-exposure the refraction recovers and the extent depends on the length of form-deprivation. The recovery rate is faster during the first 3 days and then slower after 3 days. The mechanism of form-deprivation myopia in guinea pig eyes is similar to that of myopia in juvenile human beings.

[Leber's hereditary optic neuropathy may be associated with the mitochondrial tRNAGlu A14693G mutation in three Chinese families].

We reported here the clinical, genetic and molecular characterization of three Han Chinese families with Leber's hereditary optic neuropathy. Ophthalmologic examinations revealed the variable severity and age-at-onset of visual loss among probands and other matrilineal relatives of these families. Strikingly, these families exhibited extremely low penetrances of visual impairment. Sequence analysis of complete mitochondrial genomes in these pedigrees identified the known homoplasmic tRNAGlu A14693G mutation and distinct sets of polymorphism belonging to haplogroups Y1b, Y1 and Y1, respectively. The A14693G mutation occurs at the extremely conserved nucleotide (conventional position 54) of tRNAGlu. Thus, this mutation may alter structural formation and stabilization of functional tRNAs, thereby leading to a failure in tRNA metabolism and mitochondrial dysfunction involved in visual impairment. However, none of other variants showed the evolutionary conservation and functional significance. These observations suggested that the tRNAGlu A14693G mutation may be involved in the pathogenesis of optic neuropathy in these families.

[Leber's hereditary optic neuropathy and limbs abnormity claudication may be associated with the mitochondrial ND1 T3866C mutation].

Mutations in mitochondrial DNA have been associated with a wide spectrum of clinical abnormalities. We reported here the clinical, genetic and molecular characterization of a five-generation Han Chinese pedigree with Leber's Hereditary Optic Neuropathy (LHON) and limbs abnormity claudication. Of 27 matrilineal relatives, four exhibited only LHON, one suffered from only limbs abnormity claudication, and four had both LHON and limbs abnormity claudication. Sequence analysis of mitochondrial genome in this family identified the known T3866C mutation in ND1 gene and other 43 variants belonging to the Asian haplogroup D4a3. The T3866C (I187T) mutation resulted in the replacement of isoleucine at position 187 with theronine. The isoleucine at position 187 located at one of transmembrane domain in ND1 polypeptide. The isoleucine at position 187 was extremely conserved among 29 organisms, while other variants showed no evolutionarily conservation. Furthermore, the T3866C was absence in 135 Chinese control subjects. The T3866C mutation likely alters the complex I activity, which causes mitochondrial dysfunction associated with LHON and limbs abnormity claudication. Therefore, the T3866C mutation is likely associated with LHON and limbs abnormity claudication.

Correlation between myopia and major biometric parameters of the eye: a retrospective clinical study.

PURPOSE: To investigate the relationship between myopia and changes in ocular biometry and macular thickness in young adults. METHODS: Two hundred sixteen eyes from 108 adults (23.3 +/- 6.3 years old, mean +/- SD) were measured for refractive status, corneal curvature, and axial components of the eye. Macular thickness was measured in 118 eyes (59 subjects) by optical coherence tomography. All eyes were categorized into emmetropia, low, moderate, or high myopia based on the refractive status. Biometric results from right eyes of all subjects were compared between sub-groups with the linear correlation analyzed between refraction and other parameters for each group. RESULTS: The vitreous chamber depth was longest in high myopia, followed by the moderate myopia group, the low myopia group and finally the emmetropic group (p < or = 0.004). Average thickness of the inner and outer ring macula in all the myopia groups was significantly thinner than in the emmetropia group (p < or = 0.021). Among different macular regions, the inferior quadrant of the outer ring was consistently the thinnest in myopia. Corneal curvature, anterior chamber depth, and lens thickness measures were not associated with myopia. CONCLUSIONS: Myopia in young adults is associated with an increase in vitreous length and a decrease in para-foveal thickness. The thinness in the retinal region inferior to the fovea appears to be more highly correlated with myopia than any other retinal region.

[Form deprivation myopia in C57BL/6 mice].

OBJECTIVE: To investigate the changes of refraction and ocular biometric parameters in form deprived myopia, and try to find the effective duration to induce significant myopic shift in C57BL/6 mice. METHODS: It was an experimental study. Seventy-four C57BL/6 mice, approximately 23 days old, were divided into three groups randomly: FD (Form-deprivation), Recovery and Normal control groups. FD group was treated with diffuser worn on one eye for 2 weeks (n = 12), 3 weeks (n = 20) and 4 weeks (n = 18), respectively. In Recovery group, diffusers were removed after 4 weeks form deprivation, and vertical meridian refraction and other biometric parameters were performed immediately on 4(th) and 7(th) day. The same measurements were performed in the normal control group at the same time-points. Refraction was measured by photoretinoscopy and corneal radius of curvature (CRC) was measured by a modified keratometry. Corneal thickness (CT), anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL) were measured by optical coherence tomography (OCT) with focal plane advancement. RESULTS: The FD eyes were approximately -0.85 D more myopic compared to the fellow and the normal control eyes after 2 weeks form deprivation (P > 0.05). After 3 weeks form deprivation, treated eye had a obvious myopic shift (about -4.27 D) compared to fellow eye, with increased vitreous chamber depth and axial length, however, there was no statistic difference among FD eye, fellow eye and control eye. And after 4 weeks form deprivation, treated eyes were induced significant myopic shift (about -5.22 D) compared with the fellow eye. The difference in refraction of form-deprived and fellow eyes was significantly correlated with the difference in vitreous chamber depth and axial length, which indicate that the induced myopia was mainly axial. The relative myopia shifted rapidly diminished in 4 days after removing the diffuser, followed by a slower recovery. A complete refraction recovery occurred by 7 days after removal of the diffuser compared to the fellow and normal control eyes (P > 0.05). CONCLUSION: Form deprivation myopia can be induced in C57BL/6 mice, but it required longer period than other animals; A complete recovery occurred by 7 days after removal of the diffuser.Optical Coherence Tomography is a useful instrument to measure mouse eye dimension.

[Challenges of researches on visual acuity charts for near].

Near "words" visual acuity testing is implemented in clinics to meet the exams for read demanding. Therefore, diversity formats or versions of near "words or characters" visual acuity occur. However, near visual acuity chart with the mandarin character as basic target has been debated all the time. It is due to the complexity of the mandarin characters and the comprehensive of reading while having the meaningful characters as basic targets. This article will be focused on these debates.

[Dose the mice is ideal animal myopia model?].

Myopia animal model plays an important role in mechanism study on myopia. Recently, mice are increasingly used in myopia animal model. Using mouse as myopic animal model has several advantages, especially in the mechanism study. However, the mice eye is much smaller in size than other animal eyes, therefore it is very difficult to measure the refraction and ocular dimensions in vivo. Here are summaries and comments round disputed issues which are expected to be useful for animal myopia researches.

[Expression of retinoid acid receptors in human scleral fibroblasts and regulation of growth of fibroblasts by retinoic acid].

OBJECTIVE: The aim of this study was to identify the presence of retinoid acid receptors in cultured human scleral fibroblasts and the effect of retinoic acid (RA) on the regulation of cell growth. METHODS: Human scleral fibroblasts from three donors were isolated and cultured in Dulbecco Modified Ealge's Medium. Cells from the third or fifth generation were used in the present study. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was used to detect the expression of retinoid acid receptor subtypes in the fibroblasts. RA was added to the culture medium at concentrations of 0.01, 0.10, 1.00, 10.00 and 100.00 nmol/L, separately. Cells were counted and statistically analyzed six days after being treated with RA. Each strain of the cells was examined three times. RESULTS: Cultured fibroblasts mainly showed a bipolar or spindle-shaped morphology with an average time of 2 to 3 days for each division. RT-PCR showed mRNA expression of six subtypes of RA receptors (RAR alpha, RAR beta, RAR gamma, RXR alpha, RXR beta, and RXR gamma). The proliferation of scleral fibroblasts was inhibited by 2.2%, 17.6%, 37.6%, 43.8% and 63.2% following the treatment with 0.01, 0.10, 1.00, 10.00 and 100.00 nmol/L of RA, respectively. Cell proliferation in RA-treated samples reduced significantly as compared to the control samples (P < 0.05) when the RA concentration exceeded 0.10 nmol/L. CONCLUSIONS: Six retinoid acid receptor subtypes are present in cultured human scleral fibroblasts and the growth of scleral fibroblasts was inhibited significantly by retinoic acid. These findings indicate that the sclera is a potential site of action for the retinoid acid during progression of myopia.

[Leber's hereditary optic neuropathy is associated with the mitochondrial G11696A mutation in two Chinese families].

OBJECTIVE: To report the clinical, genetic, and molecular characterization of two Chinese families with Leber's hereditary optic neuropathy (LHON). METHODS: Ophthalmological examinations showed that only probands in two families exhibited visual loss at the age of 10 and 17 years respectively. The entire mitochondrial genome of two probands was PCR amplified in 24 overlapping fragments using sets of oligonucleotide primers. RESULTS: Mutational analysis of mitochondrial DNA (mtDNA) in these pedigrees revealed the absence of three common LHON associated G11778A, G3460A and T144484 mutations but the presence of homoplastic LHON associated ND4 G11696A mutation, which was present in one out of 167 Chinese healthy controls. CONCLUSION: Sequence analysis of the complete mitochondrial genomes in two pedigrees showed the distinct sets of mtDNA polymorphisms, belonging to Eastern Asian haplogroup D4. The incomplete penetrance of visual loss and the presence of one in 167 controls suggested that this mutation itself is insufficient to produce a clinical phenotype and other modifier factors play a role in the phenotypic manifestation. The lack of functional mtDNA variants in these pedigrees ruled out the role of mitochondrial background in the phenotypic expression of visual loss. Therefore, nuclear modifier gene(s) or environmental factor(s) may play a role in the phenotypic expression of the LHON-associated G11696A mutation in two Chinese pedigrees.

[Myopic proptosis and the associated changes in axial components of the eye].

OBJECTIVE: To investigate the correlation between proptosis and changes of axial components in myopic eyes. METHODS: One hundred and eighty-nine myopic and emmetropic eyes were included. There are one hundred and eighty-three right eyes and six left eyes. Based on axial length (AL), subjects were divided into three groups: low-myopia & emmetropia group, moderate myopia group, high myopia group. Refraction of the eye (SE, spherical equivalent) was measured by retinoscopy examination under mydriasis. Proptosis was measured by Exophthalmometer (K-0161 Hertel-Type). Axial components including axial length and corneal curvature and were measured by partial coherence laser interferometry (IOL-master). The correlation in results among proptosis, axial components, and refraction was evaluated. RESULTS: The proptosis in high myopia group was bigger than in the other groups (P < 0.01). The proptosis in moderate myopia group was bigger than in low-myopia and emmetropia group (P < 0.01). The axial length was shorter than 25 mm in low-myopia and emmetropia group, from 25.00 to 27.00 mm in moderate myopia group and equal or longer than 27 mm in high myopia group. There was an increasing trend in proptosis [ranging from (14.66 +/- 1.94) mm, (16.16 +/- 1.40) mm to (18.30 +/- 1.63) mm] and axial length [ranging from (23.54 +/- 0.73) mm, (25.77 +/- 0.53) mm to (30.08 +/- 2.09) mm] among the three groups, the order of groups in the ranging was from low-myopia and emmetropia group, moderate myopia group to high myopia group. There was a highly significant correlation between proptosis and AL (R(2) = 0.990, F = 18 450.30, P < 0.01). Refraction results in low-myopia and emmetropia group, moderate myopia group and high myopia group were (-0.76 +/- 1.29) diopters (D), (-5.33 +/- 2.37) diopters (D) and (-15.92 +/- 5.12) diopters (D) respectively. There was a moderate correlation between proptosis and SE (R(2) = 0.500, F = 187.05, P < 0.01). There was a highly significant correlation between axial length and refraction (R(2) = 0.892, F = 1537.83, P < 0.01). CONCLUSION: Myopic proptosis increases with the increasing AL and SE of the eye. The eyeball tends to expand backward and proptosis forward with the increasing AL and the proptosis forward appears to be more obvious.

[Expression of dopamine receptor D2 and adenosine receptor A2A in human retinal pigment epithelium].

OBJECTIVE: The aim of this study was to identify the presence of dopamine receptor D2 and adenosine receptor A2A in human retinal pigment epithelium (RPE) in order to determine whether the RPE is a potential site of action for these two receptors. METHODS: RPE Cells were isolated and cultured. Reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry were performed to detect the expression of D2 and A2A receptors in the RPE. RESULTS: RT-PCR analysis showed that mRNA of D2 and A2A receptors were expressed in the RPE. D2 and A2A receptors were distributed in the RPE by immunocytochemistry. CONCLUSIONS: This study demonstrated the presence of D2 and A2A receptors in human RPE at both mRNA and protein levels. D2 and A2A receptors may play an important role in the maintenance of the function of human retinal pigment epithelium. Furthermore, their cooperation appeared to be important in the development of axial myopia and retinal and choroidal neovascularization.

[Expression of muscarinic acetylcholine receptor-1 in human retinal pigment epithelium].

OBJECTIVE: The aim of this study was to identify the presence of muscarinic acetylcholine receptors-I (M1 receptor) in human retinal pigment epithelium (RPE) in order to determine the role of M1 receptor in the maintenance of function of RPE and its role in the occurrence and development of myopia. METHODS: The 3rd-5th passages of RPE cells established in our laboratory were used in the present study. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect mRNA expression of M1 receptor in cultured RPE. Immunocytochemistry was used to detect M1 receptor protein in the RPE cells. RESULTS: Cultured RPE demonstrated mRNA expression of M1 receptor in RT-PCR. Protein of M1 receptor was presented in the RPE under immunocytochemistry. CONCLUSIONS: This study demonstrated the presence of M1 receptor in human RPE at both mRNA and protein levels. M1 receptor plays an important role in the maintenance of function of RPE. Injection of M1 receptor antagonist into the vitreous can delay the occurrence and inhibit the development of myopia, which is possibly related to the inhibition of RPE cells function.