Genomic and phylogenetic characterization of a bunya-like virus from the freshwater Chinese mitten crab Eriocheir sinensis.

The freshwater Chinese mitten crab (Eriocheir sinensis), an indigenous crustacean in China, has been cultured for more than 30 years. It was reported that the bunya-like virus from Eriocheir sinensis (EsBV) was associated with the tremor disease (TD), which causes high mortality and has a serious impact on production. In this study, full-length genome sequences of EsBV were pursued using next generation sequencing; the genome of EsBV was found to be composed of 6.7 kb L, 3.3 kb M, and 0.8 kb S segments, respectively. PCR detection based genomic sequences showed that the positive rate of EsBV reached 40% in crabs from farming ponds. EsBV had the highest similarity with the Wenling crustacean virus 9, an unassigned, negative sense ssRNA virus. EsBV clustered with the Wenling crustacean virus 9 firstly, and then the branch clustered with Peribunyaviridae clade in every phylogenetic tree - based on L, M and S encoded sequences, respectively, indicating that EsBV can be classified in the family Peribunyaviridae, to which the orthobunyaviruses belongs, but not belonging to any known genera in the family Peribunyaviridae. There were unique complimentary terminal sequences for EsBV, with only partial consensus with members from the orthobunyaviruses. We believe that the findings of this research will be vital for future research about EsBV and will also go a long way in illuminating its relationship with TD. Keywords: Eriocheir sinensis; tremor disease; bunyavirus; EsBV; genome sequences.

[Patients of Escherichia coli bloodstream infection: analysis of antibiotic resistance and predictors of mortality].

Objective: To analyze the drug resistance of Escherichia coli (E.coli) from bloodstream infection (BSI) and the predictors of mortality in E. coli bloodstream infection (BSI). Methods: The clinical data of 139 E. coli BSI cases diagnosed from January 2012 to December 2015 in The Second Affiliated Hospital of Zhejiang University School of Medicine, Lanxi Branch (Lanxi People's Hospital), Zhejiang Province, were retrospectively analyzed. The antimicrobial susceptibility testing was performed using Vitek 2 system. Extended-spectrum beta-lactamases (ESBLs) were detected by disk diffusion confirmatory testing. The factors associated with ESBLs-producing strains were identified by univariate analysis. Multivariate analysis was used to identify independent predictors of infection mortality by applying Logistic regression. Results: 42.4% of E. coli isolates were ESBLs-producing. The resistant rate of imipenem was 0.7%. The percent of ESBLs in hospital-acquired infection was higher than that in community-acquired infection but without statistical significance (48.7% versus 40.0%, P=0.350). Univariate analysis suggested that the percent of ESBLs-producing strains in BSI happened on ≥15 d after admission and in BSI of biliary tract infection source was 76.9% and 68.0%, which were much higher than those in BSI happened on <15 d after admission and in BSI of non-biliary tract infection source (34.6% and 36.8%, P=0.013 and 0.004). The overall mortality of E. coli BSI was 13.7%. Multivariate Logistic regression analysis indicated that Sequential Organ Failure Assessment (SOFA ) score (OR=1.393, P<0.001), ceftazidime non-susceptibility (OR=4.444, P=0.018) and liver cirrhosis (OR=13.513, P=0.001) were independent risk factors of mortality. Conclusions: The frequency of ESBLs-producing E. coli was high in primary hospital of Zhejiang Province. SOFA score, ceftazidime non-susceptibility and cirrhosis were predictors of poor outcome in E. coli BSI.

Mitochondrial oxygen metabolism in primary human lens epithelial cells: Association with age, diabetes and glaucoma.

PURPOSE: The hypoxic environment around the lens is important for maintaining lens transparency. Lens epithelial cells (LECs) play a key role in lens metabolism. We measured oxygen consumption to assess the role of human LECs in maintaining hypoxia around the lens, as well as the impact of systemic and ocular diagnosis on these cells. METHODS: Baseline cellular respiration was measured in rabbit LECs (NN1003A), canine kidney epithelial cells (MDCK), trabecular meshwork cells (TM-5), and bovine corneal endothelial cells (CCEE) using a XF96 Extracellular Flux Analyzer (Seahorse Bioscience, North Billerica, MA), which measures oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in vitro. Following informed written consent, lens capsule epithelial cells were obtained from patients during cataract surgery and were divided into small explants in 96-well plates. Capsules were removed when LECs became confluent. OCR was normalized to the number of cells per well using rabbit LECs as a standard. The effect of patient age, sex, race, and presence of diabetes or glaucoma on oxygen consumption was assessed by using the Mann-Whitney U test and multivariate regression analysis. RESULTS: Primary LECs were obtained from 69 patients. The OCR from donors aged 70 and over was lower than that of those under 70 years (2.21±1.037 vs. 2.86±1.383 fmol/min/cell; p<0.05). Diabetic patients had lower OCR than non-diabetic patients (2.02±0.911 vs. 2.79±1.332fmol/min/cell; p<0.05), and glaucoma patients had lower OCR than non-glaucoma patients (2.27±1.19 vs. 2.83±1.286 fmol/min/cell; p<0.05). Multivariate regression analysis confirmed that donors aged 70 and over (p<0.05), diabetic patients (p<0.01), and glaucoma patients (p<0.05) had significantly lower OCR, independent of other variables. Gender and race had no significant effect on OCR. CONCLUSIONS: The lower oxygen consumption rate of human LECs in older donors and patients with diabetes or glaucoma could contribute to cataract development. Diabetes and glaucoma are particularly important factors associated with decreased OCR, independent of age. Ongoing studies are examining pO2 at the anterior surface of the lens in vivo and oxygen consumption in the patient's LECs.

EGFR, HER2 and HER3 expression in primary colorectal carcinomas and corresponding metastases: Implications for targeted radionuclide therapy.

Members of the epidermal growth factor receptor, EGFR, family are interesting as targets for radionuclide therapy using targeting agents labeled with α- or ß-emitting radionuclides, especially when EGFR-positive colorectal carcinomas, CRC, are resistant to EGFR inhibiting agents like cetuximab and various tyrosine kinase inhibitors. The expression of EGFR, HER2 and HER3 was therefore analyzed in CRC samples from primary tumors, corresponding lymph node metastases and, in a few cases, liver metastases. The expression of HER2 and EGFR was scored from immunohistochemical preparations using the HercepTest criteria 0, 1+, 2+ or 3+ for cellular membrane staining while HER3 expression was scored as no, weak or strong cytoplasm staining. Material from 60 patients was analyzed. The number of EGFR 2+ or 3+ positive primary tumors was 16 out of 56 (29%) and for lymph node metastases 8 out of 56 (14%) whereas only one out of nine (11%) liver metastases were positive. Thus, there was lower EGFR positivity in the metastases. Only one among 53 patients was strongly HER2 positive and this in both the primary tumor and the metastasis. Eight out of 49 primary tumors (16%) were strongly HER3 positive and the corresponding numbers for lymph node metastases were 9 out of 49 (18%) and for liver metastases 2 out of 9 (22%). The observed number of strongly EGFR positive cases was somewhat low but EGFR might be, for the cases with high EGFR expression in metastases, a target for radionuclide therapy. HER2 seems not to be of such interest due to rare expression, neither HER3 due to mainly expression in the cytoplasm. The requirements for successful EGFR targeted radionuclide therapy are discussed, as well as patient inclusion criteria related to radionuclide therapy.

Dynamic modulation of cytoskeleton during in vitro maturation in human oocytes.

OBJECTIVE: To investigate the role of cytoskeleton in several important dynamic events during in vitro maturation of human oocytes. STUDY DESIGN: Human germinal vesicle stage oocytes were divided randomly into control and study groups. After cultured for 24 hours, chromatin state and position, spindle formation and migration, cortical granules, and mitochondria distribution were evaluated. RESULTS: In colchicine group, spindles did not form. Cortical granules migrated to the cortex but mitochondria maintained the peripheral distribution pattern in most of the oocytes. In cytochalasin B group, the migration of spindle and chromosomes to the cortex was prohibited. Microfilaments disruption influenced cortical granules migration but not redistribution of mitochondria. CONCLUSION: Meiosis progression could not go beyond metaphase I stage when microtubule or microfilament polymerization was prohibited in human oocytes. The migration of cortical granules to the cortex and redistribution of mitochondria to the inner cytoplasm were mediated by microfilaments and microtubules, respectively.

Polymorphisms of the GSTM1, GSTP1, MPO, XRCC1, and NQO1 genes in Chinese patients with non-small cell lung cancers: relationship with aberrant promoter methylation of the CDKN2A and RARB genes.

An association between functional polymorphisms of genes resulting in decreased detoxification of carcinogens or DNA repair and aberrant promoter methylation is an attractive hypothesis in lung carcinogenesis. The genotypes at polymorphic sites of the glutathione S-transferase (GST) M1 (null/wildtype) and P1 (nucleotide 2627 A/G), myeloperoxidase (MPO) (nucleotide -463 G/A), X-ray repair cross-complementing group 1 (XRCC1) (nucleotides 26304 C/T; 28152 G/A), and NADPH quinine oxidoreductase (NQO1) (nucleotide 609 C/T) genes in 75 Chinese patients with non-small cell lung cancer (NSCLC) were characterized with polymerase chain reaction-restriction fragment length polymorphism. Results were correlated with aberrant methylation of the CDKN2A (alias p16(INK4A)), retinoic acid receptor beta (RARB), methylguanine-DNA methyltransferase (MGMT), and death-associated-protein (DAP) kinase genes in the tumors. In comparison with an age-matched control, none of the polymorphisms were associated with increased lung cancer risks. In male patients, however, the MPO -463 GG homozygous state was associated with CDKN2A (alias p16(INK4A)) methylation (odds ratio OR=3.63, 95% confidence interval CI=1.26-10.51), and the XRCC1 26304 T allele in the heterozygous/homozygous state was associated with methylation of CDKN2A (OR=6.13, 95% CI=1.55-24.16) and RARB (OR=7.67, 95% CI=1.62-36.18). In female patients, the GSTP1 G allele in the heterozygous/homozygous state was associated with RARB methylation (OR=18.0, 95% CI=0.76-427.29). These results showed that functional deficiencies in metabolic pathways that protect cells from carcinogen induced DNA damage might be linked to aberrant promoter methylation of the CDKN2A and RARB genes during lung carcinogenesis.

Aberrant promoter methylation in Chinese patients with non-small cell lung cancer: patterns in primary tumors and potential diagnostic application in bronchoalevolar lavage.

This study was aimed at defining patterns of aberrant gene methylation in non-small cell lung cancer (NSCLC) in Chinese patients and its use in detecting cancer cells in bronchoalveolar lavage (BAL). The methylation-specific PCR (MSP) was used to study methylation of the p16, retinoic acid receptor-beta (RARbeta), death-associated protein (DAP) kinase, and O(6)-methylguanine-DNA-methyltransferase (MGMT) genes in 75 NSCLCs [44 adenocarcinomas and 31 squamous cell carcinomas (SCCs)] and 68 BALs from suspected lung cancers. More females had adenocarcinoma than SCC (11 of 44 versus 2 of 31, P = 0.04). Aberrant methylation in at least one gene was found in 63 of 75 (84%) NSCLCs. p16, RARbeta, DAP kinase, and MGMT methylation was similar in adenocarcinoma and SCC. However, females with NSCLC showed more frequent p16 methylation than males (12 of 13 versus 36 of 62, P = 0.02), because of more frequent p16 methylation in female adenocarcinomas (10 of 11 versus 17 of 33, P = 0.02). This sexual difference was not observed in RARbeta, DAP kinase, and MGMT. At 92%, the frequency of p16 methylation in Chinese female NSCLC is one of the highest known. For BAL, MSP and cytological analysis showed concordant and discordant results in 25 of 68 and 43 of 68 samples. Of 41 MSP+/cytology- cases, 35 were eventually shown to have malignant lung lesions, 4 were at high risk but had no evidence of lung cancer, and 2 were lost to follow-up. There were two MSP-/cytology+ cases. Frequent gene methylations were seen in Chinese NSCLC patients. More frequent p16 methylation was seen in female patients. MSP is a useful molecular adjunct for cancer cell detection in BAL samples.

Pressure assessment in intercavernous embedding of bulboperineal urethra for treatment of urinary incontinence after prostatic operation.

AIM: To put forward criteria for the pressure assessment in the operation of intercavernous embedding of bulboperineal urethra for the treatment of urinary incontinence after prostatic operation. METHODS: A F14 urethral catheter is inserted during the operation and upon suturing the corpora cavemosa centrally, the catheter is slowly pushed in and pulled out in order that the operator feels a certain degree of close-fit resistance. The degree of tightness of the stitches, which regulate the compression pressure, is adjusted in accordance with this close-fit sensation. To further ascertain the adequacy of the force of compression, the bladder is filled with 300 ml physiological saline and observe the appropriateness (size and continuity) of the outflow stream when the lower abdomen is depressed with a pressure of 80-90 cm H2O. The operation was given to six patients suffered from urinary incontinence for 20 or more months after prostatic operation. RESULTS: Five cases achieved complete recovery, while the therapeutic effect of the 6th one was not satisfactory. A second stage operation was carried out 3 months later with the addition of one more stitch both proximally and distally to reinforce the compression force. The condition was improved dramatically. The follow-up period averaged 3.5 years. CONCLUSION: The adequacy of the compression pressure exerted by the juxtaposed corpora cavernosa is the key point determining the outcome of the operation. The measures for assessing the compression pressure suggested by the authors are helpful in obtaining the good results of the present paper (6/6 success) as compared with 25/34 success in the previous report.

Observation of nonlinear acoustic effects at isotropic solid-solid interfaces.

The second harmonic generation of SV shear waves at isotropic solid-solid interfaces is experimentally studied. The amplitude of shear waves is measured for the interfaces of glass-air, glass-iron, glass-copper, and glass-aluminum. The measured angular relation of amplitude of the second harmonic wave is compared with theory and the agreement is reasonably good. The influence of the physical state of the interface on second harmonic generation is also observed. It is found that the second harmonic generation is sensitive to the interface state.

Characteristics of cataracts in the Chinese Singaporean.

PURPOSE: To conduct an epidemiological survey of cataracts and examine the characteristics of lens opacities in Chinese Singaporeans. The results are then compared with those from two similar surveys previously done in Japan in Noto Area, Honshu, and Amami, Kyushu, respectively. SUBJECTS AND METHODS: 468 subjects of > or = 50 years of age, who responded to the invitation to participate, were examined. Examination principally included photo-documentation of the anterior and posterior segments of both eyes. Evaluation and grading of lens opacities were done using graphical analysis of Scheimpflug and retro-illumination images. Inter-group comparisons were based on statistical analysis of cataract prevalence and distribution. RESULTS: The prevalence of clear lenses decreased with aging with no significant difference between males and females--a finding common to Singapore and the two Japanese study groups. The prevalence of cataracts (or lens opacities of Grade II and above) in 60-79 year-old Singapore subjects was significantly higher than Noto and Amami subjects in the same age group. Further, cortical opacity was the main type in Singapore subjects in their 50s and which was significantly higher than Noto subjects of the same age group. In all age groups, the distribution and prevalence of both nuclear and subcapsular types in the Singapore group were higher than the two Japanese study groups. CONCLUSIONS: Cataracts in Chinese Singaporeans are characterized by a high prevalence of nuclear opacities which was generally seen in tropics and sub-tropics. Our study also suggested the involvement of solar-UV in cortical cataracts as well as that of additional risk factors, such as environmental temperature and race, in nuclear and subcapsular cataract formation.

Changes in adhesion complexes define stages in the differentiation of lens fiber cells.

PURPOSE: During their differentiation, lens fiber cells elongate, detach from the lens capsule, associate at the sutures, and degrade all cytoplasmic membrane-bound organelles. Changes in the expression or organization of cell adhesion and cytoskeleton-associated proteins were correlated with these events during fiber cell differentiation in chicken embryos. METHODS: Fixed or living lenses were sliced with a tissue slicer, permeabilized or extracted with detergents, stained with antibodies or fluorescent-labeled phalloidin, and viewed with a confocal microscope. The distribution of N-cadherin in elongating and mature fiber cells was determined by Western blot analysis. Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the distribution of vinculin and paxillin transcripts. RESULTS: Staining for N-cadherin and band 4.1 protein decreased soon after fiber cells detached from the capsule. Detergent extraction of lens sections and Western blots of dissected lens regions showed that much of this decrease in staining was due to epitope masking. Vinculin immunoreactivity was barely detectable on the lateral membranes of elongating fiber cells but increased markedly once these cells reached their maximum length and formed the sutures. Staining for paxillin was also low in elongating fiber cells but increased late in fiber cell differentiation, just before the cells destroyed their membrane-bound organelles. Spectrin and ankyrin immunoreactivity did not change when fiber cells reached the sutures. Staining for F-actin increased transiently in cells that had just reached the sutures. Messenger RNAs for vinculin and paxillin were more abundant in maturing than in elongating fiber cells. CONCLUSIONS: The adhesion complexes of lens fiber cells change in organization and composition soon after these cells finish elongating and detach from the capsule. Increased staining for vinculin and paxillin defines distinct stages of fiber cell differentiation that are intermediate between the completion of cell elongation and the time when lens fiber cells degrade their membrane-bound organelles. Remodeling adhesion complexes during fiber cell maturation may assure the stability of fiber-fiber associations, once these cells are no longer transcriptionally active.

Morphological observation on cell death and phagocytosis induced by ultraviolet irradiation in a cultured human lens epithelial cell line.

The purpose of this study is to observe dynamic morphological changes induced by ultraviolet (UV) irradiation in a cultured human lens epithelial cell line using electron microscopy, cell viability staining, time-lapsed videography and immunohistochemistry. Human lens epithelial cell line SRA 01-04 was cultured in Dulbecco's Modified Eagle Medium (DMEM) containing 20% fetal bovine serum. Subconfluent cells were irradiated under a bank of UV lamps, which emitted 275-400 nm radiation with a maximum at 310 nm. The UV intensity was 20 microW cm(-2)at dosages from 0 to 10 mJ cm(-2). Alterations in the morphology of the living cells were monitored and recorded with phase-contrast microscopy and time-lapsed videography. At different times, the cells were fixed and examined by transmission electron microscopy (TEM), diamidinophenolindole (DAPI) staining, and in situ immunohistochemistry using TdT-mediated dUTP-biotin nick end labeling (TUNEL). Cell viability was also assessed with crystal violet staining. At low doses of UV exposure (2-5 mJ cm(-2)), time-lapsed videography revealed definitive cell death that appeared to be primarily apoptotic. The dead cell debris was engulfed and phagocytosed by neighboring living cells. Phase-contrast microscopy and TEM demonstrated that, at UV 10 mJ cm(-2), the cells not only showed typical apoptosis such as nuclear membrane shrinkage, chromatin condensation, and fragmentation into apoptotic bodies, but also necrosis such as swelling of the nucleus and cell body, and disruption of the plasma membrane. In support, DNA staining and in situ immunohistochemical reactions in the UV irradiated cells were both positive. The phagocytotic process was also seen with TEM. UV irradiation thus appears to cause both apoptosis and necrosis in the cultured human lens epithelial cell line. Active migration and phagocytosis of the cells appear to be stimulated by UV-induced damage. These findings may also aid in the understanding of UV injury and repair mechanisms of lens epithelial cells in vivo.

Refractive errors in Singapore and Xiamen, China--a comparative study in school children aged 6 to 7 years.

PURPOSE: To compare and contrast the prevalence of myopia and other refractive errors in Xiamen city, Xiamen countryside (Southern China), and Singapore. METHODS: One hundred thirty-two schoolchildren aged 6 to 7 years from Xiamen city, 104 from Xiamen countryside, and 146 from Singapore city were recruited to join the study. Cycloplegic autorefraction, keratometry, and biometry measurements were performed on all children. RESULTS: The prevalence of myopia was 12.3% in Singapore city, 9.1% in Xiamen city, and 3.9% in Xiamen countryside. The prevalence of astigmatism was higher in Singapore compared with Xiamen. The rates of hyperopia and anisometropia were similar in all three locations. CONCLUSIONS: The myopia rate in Singapore city was higher than in Xiamen city; the lowest rates were found in Xiamen countryside. As the Chinese population from all three sites is of similar genetic stock (predominantly from Southern China), it is postulated that the differences in myopia rates in these three localities may be related to environmental factors.

Optimization of composite transducer designing in high frequency applications.

The main obstacle to constructing a wide bandwidth and high frequency composite transducer comes from its internal vibration field fluctuation, which is aggravated as frequency increases. We found an optimized structure of 2-2 composite in which the vibration field in both phases remains nearly uniform over a wide frequency range and the piezoelectric coupling coefficient reaches its maximum value simultaneously. This article also proposes a modified representation to calculate more precisely the effective piezoelectric coupling coefficient when the vibration fluctuation has been taken into account.

Epidemiological studies on UV-related cataract in climatically different countries.

Cataract epidemiological surveys applying objective judgement through lens images in the climatically different places of Noto and Amami, Japan, Singapore and Reykjavik, Iceland yielded several significant results about the influence of solar UV. 1) The percentage of transparent and of lens opacification was significantly higher in the Reykjavik subjects than in the Singaporeans. 2) The percentages including early changes were higher in Amami and Singapore than in Noto and Reykjavik. 3) Progressed lens opacification was highest in Singapore. While the main type of lens opacification was cortical in Noto and Reykjavik, that of Singapore was nuclear. 4) A significant correlation between cortical opacification and the history of time spent outdoors was noticed. The UV risk for formation and/or progression of cortical opacification should be acceptable from the epidemiological standpoint.

UV damage to the eye lens: further results from animal model studies: a review.

UV irradiation has the potential to induce the development of lens opacities. This has been demonstrated since long with animal experiments. Unfortunately these animal cataracts did not explain or elucidate the epidemiological observation that the frequency of human cataracts--such as the so called senile cataract--is remarkably higher in regions with increased cosmic UV irradiation or in the population being in close professional contact with UV-irradiation. The main problem was that the type of UV induced animal cataracts differs remarkably with respect to onset, localization of the opacity, size and its timely progression from the cataract classes observed in human. The research of the last 10 years comes to the conclusion that beside the direct (acute) damage--as seen in animal studies due to high UV dosages--we have to realize a syn- or co-cataractogenic potential of UV irradiation even below the threshold dose which is able to accumulate in the lens and to initiate together with other risk factors (chronic damage) the opacification of the lens. The mechanism for the animal cataract and the human cataract (with an UV risk participation) are different. The epidemiological research about cataract frequency in different regions of the world have to take into account that UV irradiation--even below a threshold dose--is a possible risk among the multifactorial pathogenesis of human cataract.

Coupled mode theory for nonlinear piezoelectric plate vibrations.

Coupled-mode equations were developed for thickness-longitudinal vibrations of piezoelectric plate resonators. The equations describe the resonator as a parametrically excited nonlinear vibrational system with two degrees of freedom. Thus one can examine the behavior of piezoelectric resonators from a nonlinear dynamic point of view. In the present paper the derivation of the equations is given. As an example of the application of the equations, the behavior of the resonator in the vicinity of primary resonance is discussed. The method of multiple scales is used to solve the coupled-mode equations. An experiment which verises the amplitude-driving voltage relation predicted by the theory is conducted for LiNbO(3) resonators.

In vitro UV-B effect on lens protein solutions.

To investigate the effects of UV-B exposure on the protein solutions of different lens parts, rabbit lenses were separated into the equator (Eq), anterior cortex (Ac), nucleus (Nu) and posterior cortex (Pc). After homogenization, the water-soluble protein from each part was irradiated with UV-B at 0 to 0.225 J/cm2. Alterations in the content of protein SH, carbonyl groups, light scattering intensity and SDS-PAGE pattern were measured to compare the effect of UV-B on the protein solutions of various lens parts with or without additional GSH to test its preventive effect. The results showed that after UV-B irradiation, the protein sulfhydryl groups are gradually reduced. The nonprotein thiol (GSH added to the protein solution) was lost more rapidly than the protein sulfhydryl. The high molecular bands on the SDS-PAGE pattern mainly aggregated with disulfide. UV-B damage also increased the content of carbonyl groups and light scattering, irrespective of the lens parts. Lens proteins from the equator suffered the least damage while those of the nucleus were most strongly affected by UV-B exposure. This study suggests that the lens proteins from various lens parts have different responses to UV-B exposure; the sensitivity was in the following order: Eq < Ac < or = Pc < Nu.

Location and severity of UVB irradiation damage in the rat lens.

We investigated the location and severity of lens opacities and epithelial alterations following ultraviolet-B (UVB) irradiation in vivo, using Brown Norway rats. A group of 9 rats received 65 mJ/cm2 UVB irradiation from overhead lamps every 6 days. Lens changes were documented and evaluated by an anterior eye segment analysis system. Lens epithelial cells were examined postmortem in flat preparations. After 8 weeks of the irradiation schedule (total dose: 0.6 J/cm2), an anterior polar opacity was apparent; at 16 weeks, the opacities had progressed more deeply into the cortex. At postmortem examination, cells in the central region displayed disorganization, clumping, some pyknotic nuclei and mitosis. There were deeper opacities and cell damage was more severe above the central horizontal plane than below it. This present study demonstrated that UVB damage differed in the superior and inferior parts divided by a horizontal plane through the lens anterior pole, when the UVB source was above and there was no reflection from below or laterally. The lens epithelial cells, and associated lens fibers, are the first target of UVB irradiation.

Experimentally induced steroid cataract in the rat: a scanning electron microscopic study.

To clarify the histopathological changes of experimentally induced steroid cataract in Brown-Norway rat eyes, a scanning electron microscopic study was performed. The biomicroscopic appearance of the cataracts, which was quite similar to that of human eyes, was induced by daily application, either topically or systemically, of prednisolone acetate for 12 months. A single dose of 2 Gy X ray was given to the right eyes of all the animals 2 weeks before drug administration. Twenty-seven rats were divided into three groups: a control group (CTL), a group receiving topically administered prednisolone (TOP), and a group receiving systemically administered prednisolone (SYS). In vivo observation was performed through a slit-lamp microscope, and the lens findings were documented and objectively analyzed by an anterior eye segment analysis system over a period of 12 months. At the end of the 12-month period, X-ray-irradiated right eyes in the CTL group showed some minor lens changes on biomicroscopy, and non-X-ray-irradiated left eyes were almost normal. In the TOP and SYS groups, either with or without X-ray irradiation, lenses showed anterior and posterior subcapsular opacification; however, the grade and increase of lens opacification were higher and faster in the eyes with X-ray irradiation. Scanning electron microscopic findings of the three groups at the 12th month were as follows. In the CTL group, the X-ray-irradiated right eyes showed minor changes. In the TOP group, the X-ray-irradiated right eyes showed marked damage in the lens fibers of the anterior and posterior cortices, while the nonirradiated left eyes showed minor changes. In the SYS group, the X-ray-irradiated right eyes showed prominent cataractous disorganization of lens fibers in the shallow anterior and posterior cortices, and the non-X-ray-irradiated lenses were almost the same as those in the TOP group. These findings might suggest that even a minimum invasion of a low dose of X-ray irradiation plays a cocataractogenic or syncataractogenic role during the formation of steroid cataracts.