A new method for quantification of metamorphopsia in patients with epiretinal membrane

PURPOSE

A new method for quantification of metamorphopsia was applied to study distorted vision in patients with epiretinal membrane.

METHOD

Sixty-three patients with unilateral epiretinal membrane in the macula were examined. A modified Amsler chart (a grid of black lines on a white background measuring 12 x 12 cm with grid squares of 2 x 2 cm) was prepared. If patients saw any of the grid lines as irregular or curved, they were asked to trace these on the chart. The length of all lines drawn by the patients was measured, except those on the outer border. The length of the grid is 1200 mm, but it should be drawn longer by patients with metamorphopsia. The severity of metamorphopsia was also scored subjectively and the relationship of grid length to the subjective score and the visual acuity was analyzed.

RESULTS

The grid length ranged from 1200 to 1259 mm (mean = 1223.3 mm) and was correlated significantly with the subjective score (P <.01, rho =.387).

CONCLUSION

This method might be applicable for evaluating the severity of metamorphopsia and the surgical outcome in patients with epiretinal membrane.

Identification of four novel mutations of the XLRS1 gene in Japanese patients with X-linked juvenile retinoschisis. Mutation in brief no. 234. Online

The XLRS1 gene (HUGO-approved symbol, RS1) has been found to cause X-linked recessive retinoschisis (RS) which is characterized by splitting of the superficial layer of the retina. Recent mutation analysis of this gene revealed 82 different mutations in 214 patients with RS. We have now identified 10 mutations of the XLRS1 gene in 11 unrelated Japanese males with RS. Mutations found in these patients were; 1) a 20-kb deletion in exon 1 region; 2) mutations in the initiation sequence (M1V); 3) mutations in the splice donor site (IVS1 + 1 g-->a); 4) two nonsense mutations (Q88X, W163X); and 5) five missense mutations (E72K, Y89C, R182C, G109E, P203L). Four (M1V, Q88X, G109E, and W163X) of the 10 mutations were novel. The R182C mutation was identified in 2 unrelated patients. The 3 mutations found between exons 1 and 3 cause premature translation termination in the XLRS1 protein. The rest of the 7 mutations were clustered between exons 4 and 6. This region of the protein is homologous to the proteins implicated in cell-cell adhesion.

Macular hole retinal detachment in highly myopic eyes: ultrastructure of surgically removed epiretinal membrane and clinicopathologic correlation

PURPOSE

To elucidate the pathogenesis of macular hole retinal detachment (RD) in highly myopic eyes by investigating the ultrastructure of surgically removed epiretinal membranes (ERM).

METHODS

Five consecutive Japanese patients with macular hole RD in highly myopic eyes underwent vitrectomy with attempted removal of the ERM around the hole. The surgical specimens were examined by light microscopy and by scanning and transmission electron microscopy.

RESULTS

Extremely thin, translucent sheets of epiretinal tissue were harvested from all patients during surgery, resulting in successful retinal reattachment. Ultrastructural examination revealed that the ERM consisted of cortical vitreous and various cellular components. Fibrous astrocytes were the major cell population and extended cytoplasmic processes with membrane-associated vesicles onto the cortical vitreous. Gap junctions were observed between the interdigitating processes of fibrous astrocytes. The cortical vitreous contained abundant newly formed collagen, including fibrous long-spacing collagen, surrounded by sparsely distributed native vitreous collagen.

CONCLUSIONS

Active synthesis of new collagen may be regulated by fibrous astrocytes by means of transmission of metabolic substances through gap junctions and cytoplasmic vesicles. The frequent occurrence of newly formed collagen aggregates may subsequently lead to a diffusely condensed posterior cortical vitreous that exerts tangential traction on the posterior retina, causing macular hole RD.

Coexpression of VEGF receptors VEGF-R2 and neuropilin-1 in proliferative diabetic retinopathy

PURPOSE

To elucidate vascular endothelial growth factor (VEGF)-mediated pathogenesis of fibrovascular proliferation in diabetic retinopathy.

METHODS

Fibrovascular tissues were obtained at vitrectomy from 22 cases with proliferative diabetic retinopathy. The half-divided tissues were processed for reverse transcription-polymerase chain reaction (RT-PCR) analysis to examine the expression of VEGF isoforms and their receptors. Paraffin sections of the other half were used for immunohistochemistry for CD34, glial fibrillary acidic protein and VEGF, and in situ hybridization for VEGF.

RESULTS

RT-PCR analysis demonstrated the expression of VEGF receptors VEGF-R1, VEGF-R2, and neuropilin-1 in 12, 14, and 14 of 22 cases, respectively. Notably, VEGF-R2 and neuropilin-1 were simultaneously expressed in the identical 14 tissues. The isoform VEGF121 was constitutively expressed in all the tissues examined, whereas the expression of VEGF165 was confined to the 7 tissues that also expressed VEGF-R2 and neuropilin-1. The vascular density of fibrovascular tissues evaluated by immunohistochemistry for CD34 was significantly higher in the cases with the expression of VEGF-R2 and neuropilin-1 than in those without their expression (P < 0.01), whereas VEGF-R1 expression had no such relationship with the vascular density. The fibrovascular tissues that expressed VEGF165 together with VEGF-R2 and neuropilin-1 were found in significantly younger patients (P < 0.01). In situ hybridization and immunohistochemical studies demonstrated that glial cells in the fibrovascular tissues express and produce VEGF.

CONCLUSIONS

Coexpression of VEGF-R2 and neuropilin-1 is suggested to facilitate fibrovascular proliferation in diabetic retinopathy.

Melanocytoma of the left optic nerve head and right retrobulbar optic neuropathy compressed by a tuberculum sellae meningioma

A 40-year-old woman had a highly pigmented, slightly elevated tumor on the left optic disc. She had no visual disturbance in the left eye. The tumor was stationary for 5 years. At age 45 years, she complained of decreased visual acuity in the right eye. Magnetic resonance imaging showed a right-shifted homogeneous lesion at the tuberculum sellae. Histopathologic study of the excised lesion revealed interlacing bundles of spindle-shaped fibroblast-like cells with whorl formation. We believe that a relationship between melanocytoma of the optic nerve head and a tuberculum sellae meningioma may exist rather than a chance occurrence, as previously suggested by others.

Ultrasound biomicroscopy for examination of the sclerotomy site in eyes with proliferative diabetic retinopathy after vitrectomy

PURPOSE

We evaluated the capability of ultrasound biomicroscopy (UBM) to predict fibrovascular proliferation at sclerotomy sites in eyes with postoperative vitreous hemorrhage due to proliferative diabetic retinopathy (PDR).

METHODS

Ultrasound biomicroscopy was used for examining the sclerotomy sites in 13 eyes of 11 patients with PDR experiencing postoperative vitreous hemorrhage (PDR group). Thirty-nine sclerotomy sites (all entry sites of each eye) were examined before reoperation, and the UBM images were compared with findings obtained during revision of the vitrectomy. Thirteen eyes of 13 patients undergoing vitrectomy for nondiabetic diseases were used as controls and examined after vitrectomy.

RESULTS

The UBM images were classified into the following four categories: A, tent; B, spheroid; C, trapezoid; and N, none. The findings were distributed as follows in the PDR group: category A, 18%; B, 5%; C, 56%; and N, 21 %; and as follows in the control group: category A, 28%; B, 5%; C, 5%; and N, 62%. In the PDR group, 11 of 12 sclerotomy sites disclosing fibrovascular proliferation possessed the trapezoidal image. Mean length of trapezoidal base was 2.49+/-0.97 mm and 1.51+/-0.75 mm in the groups with and without fibrovascular proliferation, respectively (P<0.01). The average relative reflectivity of the trapezoidal image against the sclera was 0.501+/-0.169 in the fibrovascular proliferation group and 0.891+/-0.183 in the fibrous ingrowth group (P<0.01).

CONCLUSION

Ultrasound biomicroscopy is useful in detecting fibrovascular proliferation at sclerotomy sites because a large and low-reflecting trapezoidal UBM image is highly correlated to its presence.

Induction and inhibition of testicular germ cell apoptosis by fluoroacetate in rats

Fluoroacetate (FA), an inhibitor of aconitase, is known to lower the intracellular level of adenosine triphosphate (ATP), which recently has been suggested to be a possible determinant of the form of cell death, apoptosis or necrosis. To investigate which form of germ cell death occurs in FA-induced testicular toxicity, adult Sprague Dawley rats were given a single oral dose of FA (0.5 or 1.0 mg/kg) and euthanized at 3, 6, 12, 24, 48, and 72 h thereafter. Germ cell degeneration was histologically first found in early round spermatids at stage I and in spermatogonia at stages II-IV of seminiferous tubules 6 and 12 h, respectively, after dosing. Degenerating spermatogonia exhibited characteristic features of apoptosis as demonstrated by both electron microscopy and in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), whereas spermatids did not. At the 24 and 48 h time points, degenerating spermatids were continually present and subsequently formed multinucleated giant cells, while the number of degenerating spermatogonia and TUNEL-labeled spermatogonia was drastically and/or significantly decreased compared to those from the control group, indicating that spontaneous male germ cell apoptosis is inhibited. Coincident with these morphological changes, DNA laddering on gel electrophoresis was apparent only 12 h after dosing. The results demonstrate that FA induces either apoptosis or necrosis of male germ cells in the early stage after dosing and subsequently inhibits spontaneous apoptosis.

Changes in serum alpha2u-globulin levels in male rats given diethylstilbestrol and applicability to a screening test for endocrine-disrupting chemicals

alpha2u-Globulin (AUG) is a major rat urinary protein, which has a molecular weight of 16 kDa (kidney type) or 19 kDa (native type). The biosynthesis of this protein is under multi-hormonal regulation. In this study, we investigated changes in serum AUG level and their association with changes in the reproductive organs of male rats after the administration of the estrogenic chemical, diethylstilbestrol (DES) at doses ranging from 0.01 mg/kg per day to 100 mg/kg per day by gavage for 14 days. Our aim was to establish basic data for the development of a new screening method for endocrine disrupting chemicals based on serum AUG levels. DES treatment decreased the weight of testes in a dose-dependent manner; and was accompanied by atrophic histopathological changes in testes. Testis weights were significantly decreased by the group given 1 mg/kg per day DES; however, histopathological abnormalities were found in the group given 0.1 mg/kg per day DES. In four of five animals in the group given 1 mg/kg per day there was no significant decrease in testis weight and only a slight or moderate degeneration of the pachytene spermatocytes. Despite these findings, serum AUG levels in this group decreased markedly, while the serum AUG level markedly decreased even in the animals with no histopathological change in the 1 mg/kg per day or 0.1 mg/kg per day groups with no histopathological change also showed decreased serum AUG level. These results suggest that the serum AUG level may be a sensitive parameter for detecting the activity of estrogenic chemicals in intact male rats. Although a uterotropic assay has been proposed for immature female or ovariectomized female rats and is currently undergoing validation studies internationally, there is no screening method for estrogenic chemicals in intact male animals. More data on AUG changes by treatment with other estrogenic chemicals are needed in order to determine the sensitivity and specificity of this response to estrogens. Nonetheless, an AUG-based screening test for estrogenic chemicals may be useful owing to its applicability to conventional toxicity studies and an apparently higher sensitivity of this parameter compared to organ weight change or histology of testis in intact male rats and applicability to conventional toxicity studies.

Twin-image elimination experiments for three-dimensional images in optical scanning holography

Twin-image elimination in the context of optical scanning holography has recently been proposed. The proposed technique involves simultaneously acquiring sine and cosine Fresnel holograms. A complex hologram is then formed by complex addition of the holograms, and twin-image rejection is predicted by computer simulations. An experimental verification of the technique by optical acquisition of the two holograms and subsequent reconstruction of the complex hologram digitally is reported. Three-dimensional image reconstruction without twin-image noise is demonstrated.

Cytotoxic alkaloids of Pachysandra terminalis

Four steroidal alkaloids, epipachysamines B (1) and E (2), pachystermine A (3) and pachysamine E (4), were isolated as cytotoxic principles from the MeOH extract of the stems of Pachysandra terminalis SIEB. et ZUCC. (Buxaceae). These alkaloids showed cytotoxic activity against P388 and P388/ADR leukemia cells in vitro. Three of the alkaloids (1-3) were previously isolated from this plant material, and this is the first report of their cytotoxic activity. Pachysamine E (4) is a new alkaloid.

[Comparison of scleral buckling and vitrectomy for superior retinal detachment caused by flap tears]

PURPOSE

We compared the surgical results of vitrectomy and scleral buckling for uncomplicated superior retinal detachment caused by flap tears.

SUBJECTS AND METHODS

Included in the study were 225 phakic eyes of 225 patients undergoing primary surgery from January 1990 to December of 1996 for superior retinal detachment caused by flap tears; all eyes had been followed for longer than six months after surgery. The choice of procedures was based on each surgeon's preference. The cases were evaluated retrospectively and the surgical outcome and the rate of complications compared between the two groups of eyes.

RESULTS

Initial and final anatomical success rate were 92% and 100% after each procedure. Redetachment after the first procedure was due to new retinal breaks in 5 eyes, reopening of original breaks in 2 eyes of vitrectomy cases, and malpositioned buckle in 11 eyes of scleral buckling cases. Proliferative vitreoretinopathy occurred in 3 eyes of vitrectomy cases.

CONCLUSION

Primary vitrectomy was as successful as scleral buckling for superior rhegmatogenous retinal detachment. Although a high incidence of postoperative cataract formation was a major drawback, vitrectomy had some advantages over to scleral buckling.

[A new method for quantification of metamorphopsia in patients with epiretinal membrane]

PURPOSE

We have developed a new method for quantification of metamorphopsia and applied it to study distorted vision resulting from epiretinal membrane (ERM).

PATIENTS AND METHODS

We prepared a modified Amsler chart, which was a square grid formed by black lines on a white background with 12 cm on a side and divided into 2 cm quadrants. The patients were asked to trace any straight lines on the chart which appeared irregular or curved. The length of all lines traced by the patients was measured except for the outer frame. The total length of the chart itself was 1,200 mm, but it would appear longer in patients with metamorphopsia. In addition, the severity of metamorphopsia was scored subjectively as follows: 1, absent; 2, slight; 3, mild; 4, moderate; and 5, severe. The relationship of the length to the score and to the visual acuity were analysed. Sixty-three patients with unilateral ERM were examined.

RESULT

The length of the line ranged from 1,200 to 1,259 mm (mean 1,223.3 mm) and was correlated significantly to the score.

CONCLUSION

This method might be applied usefully in evaluating the severity of metamorphopsia and the surgical outcome of eyes with ERM.

A new technique for separation of posterior vitreous in vitreous surgery

To describe a new and effective technique, hydroseparation, for use in detaching the posterior cortical vitreous from the retina by the simple injection of fluid into the subhyaloid space. This technique was used in 7 eyes of 6 patients with diabetic retinopathy who had limited posterior vitreous detachment. Following core vitrectomy, a 32 gauge cannula was inserted into the subhyaloid space and a balanced salt solution (BSS) was injected. The injected fluid spread easily to the periphery, causing the vitreous cortex to be smoothly separated, except for areas with firm vitreoretinal adhesion. In those areas, we also used microscissors to separate the tissue. No iatrogenic retinal break occurred in any case. This simple technique, which exerts minimal traction force on the retina, was safe and useful for inducing posterior vitreous detachment in patients with diabetes.

Development of a compact computed tomographic apparatus for dental use

OBJECTIVE

To describe a compact computed tomographic apparatus (Ortho-CT) for use in dental practice.

METHODS

Ortho-CT is a cone-beam-type of CT apparatus consisting of a multifunctional maxillofacial imaging machine (Scanora, Soredex, Helsinki, Finland) in which the film is replaced with an X-ray imaging intensifier (Hamamatsu Photonics, Hamamatsu, Japan). The region of image reconstruction is a cylinder 32 mm in height and 38 mm in diameter and the voxel is a 0.136-mm cube. Scanning is at 85 kV and 10 mA with a 1 mm Cu filter. The scan time is 17 s comparable with that required for rotational panoramic radiography. A single scan collects 512 sets of projection data through 360 degrees and the image is reconstructed by a personal computer. The time required for image reconstruction is about 10 min.

RESULTS

The resolution limit was about 2.0 lp mm-1 and the skin entrance dose 0.62 mGy. Excellent image quality was obtained with a tissue-equivalent skull phantom: roots, periodontal ligament space, lamina dura, and cancellous bone were clearly visualized.

CONCLUSION

Ortho-CT provides three-dimensional images of excellent quality for dental use at a low entrance dose.

Comparison of the levels of hepatocyte growth factor and vascular endothelial growth factor in aqueous fluid and serum with grades of retinopathy in patients with diabetes mellitus

AIMS

To determine the relation between the stages of diabetic retinopathy (DR) and the levels of hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) in aqueous fluid and serum.

METHODS

Levels of HGF and VEGF in serum and aqueous humour obtained during ocular surgery were measured by enzyme linked immunosorbent assay in 58 diabetic patients with 32 non-diabetic patients (NDM) as controls. The patients with diabetes were classified into three groups according to the stage of DR: no DR (NDR; 15 cases), non-proliferative DR (NPDR; six cases), and proliferative DR (PDR; 37 cases).

RESULTS

No significant differences were found between any of the groups in serum concentrations of HGF or VEGF. The aqueous HGF levels increased with the stage of DR: NDM, median 397 pg/ml, range 133-930 pg/ml; NDR, 371 pg/ml, 142-1536 pg/ml; NPDR, 455 pg/ml, 162-1007 pg/ml; and PDR, 638 pg/ml, 187-2222 pg/ml. The aqueous VEGF levels in PDR (median 212 pg/ml, range 14-1216 pg/ml) were significantly higher than in NDM (105 pg/ml, 9-203 pg/ml), but aqueous HGF concentrations were unrelated to those of VEGF.

CONCLUSION

The results of the present study suggest that both HGF and VEGF present in the ocular tissues may play important roles in the progression of DR.

Doxorubicin induces male germ cell apoptosis in rats

To clarify whether apoptosis is involved in doxorubicin (DXR)-induced testicular toxicity and to identify the target germ cell type, adult Sprague-Dawley rats were treated with a single intravenous dose of DXR (8 or 12 mg/kg) and euthanized at 3, 6, 12, 24, and 48 h subsequently. Histologically, germ cell degeneration was first found 6 h after dosing in meiotically dividing spermatocytes and early round spermatids of seminiferous tubules at stage 1, and subsequently observed in spermatogonia at stages I-VI showing ultrastructural characteristics of apoptosis. Coincident with the appearance of morphological changes, degenerating germ cells were shown to be undergoing apoptosis as revealed by in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The frequency of TUNEL-labeled germ cells increased in a stage- and cell type-specific manner, the peak of frequency gradually progressing from stage I of seminiferous tubules to later stages with time after dosing, suggesting that the damaged germ cells, especially spermatogonia, gradually underwent the processes leading to apoptosis. DNA laddering on gel electrophoresis was apparent 24 and 48 h after dosing. The results demonstrate that apoptosis plays an important role in the induction of testicular toxicity caused by DXR with meiotically dividing spermatocytes and type A and intermediate spermatogonia as highly vulnerable target cells.

Octa- and nonaprenylhydroquinone sulfates, inhibitors of alpha1,3-fucosyltransferase VII, from an Australian marine sponge Sarcotragus sp

Alpha1,3-fucosyltransferase (Fuc TVII) is a key enzyme in the biosynthesis of selectin ligands. We have isolated two inhibitors of Fuc TVII from a marine sponge Sarcotragus sp. They were characterized as octa- and nonaprenylhydroquinone sulfates on the basis of spectral data. These compounds inhibited Fuc-TVII with IC50 values of 3.9 and 2.4 microg/mL, respectively.

Severe juvenile retinoschisis associated with a 33-bps deletion in XLRS1 gene

X-linked juvenile retinoschisis is a form of vitreoretinal dystrophy that is characterized by foveal and peripheral splitting of the retinal nerve fiber layer. Pathognomonic of this disorder is a microcystic radiate appearance in the fovea. We encountered a 10 year-old, mildly retarded, Japanese boy, who exhibited a widely extended macular retinoschisis bilaterally. A break in the inner layer of the left eye mimicked a lamellar macular hole, which is a rare manifestation of the disease. Peripheral retinoschisis was absent. Only a few reports have described marked bilateral macular retinoschisis that involved entire posterior pole, while various other macular findings have been reported. This patient with a severe form of retinoschisis was found to harbor the deletion of 33 base pairs, including the boundary region of exon 3 and intron 3 in the XLRS1 gene.

Development of X-ray TV M-mode and reconstructed ultrasound M-mode methods for investigating tongue movement during swallowing in humans

There were two purposes of this study. The first purpose was to introduce the "X-ray TV M-mode waveform" which is reconstructed from sequential X-ray TV images and the "reconstructed ultrasound M-mode waveform" which is delivered from ultrasound B-mode images. The second purpose was to evaluate the usefulness of these two types of waveforms in the investigation of tongue movement during swallowing. The instrument system employed in this study consisted of ultrasound and X-ray TV synchronized by a time marker. After the X-ray images and ultrasound B-mode images were recorded on an optical disk, X-ray TV M-mode waveform and ultrasound M-mode waveform were reconstructed using an MC 68030/OS-9 computer. No significant differences in quality of images were observed between the X-ray TV M-mode waveform and the reconstructed ultrasound M-mode waveform. Therefore, both waveforms of the X-ray TV M-mode and the reconstructed ultrasound M-mode are equally useful in measuring tongue movement.

Effect of TPA on aquaporin 4 mRNA expression in cultured rat astrocytes

Aquaporin 4 (AQP4) is a predominant water channel protein in mammalian brains, localized in the astrocyte plasma membrane. The regulation of AQP4 is believed to be important for the homeostasis of water in the brain, but the AQP4 regulatory mechanisms are not yet known. In this study, we investigated the effect of a protein kinase C (PKC) activator on the expression of AQP4 mRNA in cultured rat astrocytes. Cultured rat astrocytes constitutively expressed AQP4 mRNA. Treatment of the cells with 0.1 microM of phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA), an activator of PKC, caused a rapid decrease in AQP4 mRNA. This effect was time- and dose-dependent. The TPA-induced decrease in AQP4 mRNA was inhibited by a relatively specific PKC inhibitor, 1-(5-isoquinoline sulfonyl)-2-methylpiperazine (H7) in a dose-dependent manner. Moreover, prolonged treatment of the cells with TPA eliminated the subsequent decrease in AQP4 mRNA by TPA. These results strongly suggest that the TPA-induced decrease in AQP4 mRNA is mediated by PKC activation. To test whether the effect of TPA requires protein synthesis, astrocytes were pretreated with cycloheximide, an inhibitor of protein synthesis. Pretreatment of the cells with cycloheximide did not inhibit the decrease in AQP4 mRNA induced by TPA. To test whether the TPA-induced decrease in AQP4 was due to a decrease in the mRNA stability, we examined the effect of actinomycin D, an inhibitor of transcription, on TPA-treated cells. The stability of AQP4 mRNA was not decreased by the pretreatment of the cells with actinomycin D. The results suggest that AQP4 mRNA is inhibited by TPA via PKC activation without de novo protein synthesis, and that the inhibition of AQP4 mRNA could be at the transcriptional level.

Distribution and developmental changes of adenylate kinase isozymes in the rat brain: localization of adenylate kinase 1 in the olfactory bulb

Changes in the levels of three adenylate kinase isozymes (AK1, AK2, and AK3) in the rat brain during development were investigated by immunoblot analysis. The levels of AK1 and AK3 of the whole brain increased after birth, while AK2 was detected only in the early embryonic period. In the adult rat brain, high levels of AK1 were present in the olfactory bulb. Immunohistochemical analysis showed that AK1 was found predominantly in the olfactory nerve layer and the glomerular layer. In the olfactory bulb, AK1 gene expression was enhanced in the early postnatal days, whereas it remained low in the cerebellum during the first 10 postnatal days. These results suggest that the AK isozymes are involved in neuronal maturation and regeneration. The understanding of the physiological actions of adenosine and ATP as neurotransmitters/neuromodulaters in the central nervous system has improved. ATP and adenosine receptors have been found to be widely distributed over the whole brain, although the intra- and extracellular metabolism of these compounds has not been well elucidated.