Current progress and challenges in ocular surface reconstruction using cultivated epithelial sheet transplantation

The cultivated epithelial transplantation is a new surgical modality for treating a variety of severe ocular surface disorders. This type of tissue-engineered epithelial sheet provides a rapid epithelial coverage on the corneal surface that reduces inflammation and postoperative complications. Although cultivated corneal epithelial transplantation is an effective surgical strategy, autologous transplantation is limited to unilateral cases. Autologous cultivated oral mucosal epithelial transplantation (COMET) enables surgeons to reconstruct the ocular surface using autologous, non-ocular surface cells, and has opened a new pathway for treating severe, bilateral ocular surface disorders.

Coloration using higher order optical interference in the wing pattern of the Madagascan sunset moth

Colour patterns of animals' bodies are usually produced by the spatial distribution of pigments with different colours. However, some animals use the spatial variation of colour-producing microstructures. We have studied one distinctive example of such structurally produced colour patterns, the wing of the Madagascan sunset moth, to clarify the physical rules that underlie the colour variation. It is known that the iridescent wing scale of the sunset moth has the alternate air-cuticle multilayer structure that causes optical interference. The microscopic and optical investigations of various parts of the wing have confirmed that the thickness of the cuticle layers within the scale largely varies to produce the colour pattern. However, it varies in very different ways between the dorsal and ventral sides of the hind wing; the thickness gradually varies on the dorsal side from scale to scale, while the abrupt changes are found on the ventral side to form distinctive borders between differently coloured areas. It is also revealed that an unusual coloration mechanism is involved in the green part of the ventral hind wing: the colour is caused by higher order optical interference of the highly non-ideal multilayer structure. The physical mechanism of the colour pattern formation is briefly discussed with the several mathematical models proposed so far.

Aberration-correcting effect of ThinOptX IOL

PURPOSE

To evaluate spherical aberration and visual function after microincision cataract surgery using the ThinOptX rollable intraocular lens.

DESIGN

Prospective, comparative, and interventional case series.

METHODS

SettingSingle-centre institutional practice. This prospective study evaluated 58 patients with cataracts who underwent bimanual microphaco cataract surgery in both eyes. A ThinOptX lens was introduced into one eye and an Alcon Acrysof lens, as a control, into the other. One month after cataract surgery, the corneal, whole-eye, and internal spherical aberration, and contrast sensitivity in both eyes were measured. We also measured the spherical aberration in artificial model eyes bearing Acrysof and ThinOptX lenses. Two-sided paired t-test was used for assessing all data.

RESULTS

The root mean square (RMS) for both whole-eye and internal spherical aberrations was smaller in eyes bearing ThinOptX (P=0.03 and P=0.07, respectively). Although there was no statistically significant difference in the RMS for internal spherical aberration between ThinOptX- and Acrysof-bearing eyes, according to the Zernike polynomial expansion, all human and model eyes bearing ThinOptX registered negative internal spherical aberration in Z(4,0) and Z(6,0). On the other hand, all human and model eyes bearing Acrysof registered positive internal spherical aberration in Z(4,0) and Z(6,0). The ThinOptX lens yielded slightly higher contrast sensitivity in all cycles.

CONCLUSION

As the ThinOptX lens is designed for negative spherical aberration, we encountered smaller whole spherical aberrations and higher contrast sensitivity than with the Acrysof lens. The implantation of ThinOptX IOL after microincision cataract surgery yielded good visual function.

Antioxidant and hepatoprotective actions of medicinal herb, Terminalia catappa L. from Okinawa Island and its tannin corilagin

The antioxidant and hepatoprotective actions of Terminalia catappa L. collected from Okinawa Island were evaluated in vitro and in vivo using leaves extract and isolated antioxidants. A water extract of the leaves of T. catappa showed a strong radical scavenging action for 1,1-diphenyl-2-picrylhydrazyl and superoxide (O(2)(.-)) anion. Chebulagic acid and corilagin were isolated as the active components from T. catappa. Both antioxidants showed a strong scavenging action for O(2)(.-) and peroxyl radicals and also inhibited reactive oxygen species production from leukocytes stimulated by phorbol-12-myristate acetate. Galactosamine (GalN, 600 mg/kg, s.c.,) and lipopolysaccharide (LPS, 0.5 microg/kg, i.p.)-induced hepatotoxicity of rats as seen by an elevation of serum alanine aminotransferase, aspartate aminotransferase and glutathione S-transferase (GST) activities was significantly reduced when the herb extract or corilagin was given intraperitoneally to rats prior to GalN/LPS treatment. Increase of free radical formation and lipid peroxidation in mitochondria caused by GalN/LPS treatment were also decreased by pretreatment with the herb/corilagin. In addition, apoptotic events such as DNA fragmentation and the increase in caspase-3 activity in the liver observed with GalN/LPS treatment were prevented by the pretreatment with the herb/corilagin. These results show that the extract of T. catappa and its antioxidant, corilagin are protective against GalN/LPS-induced liver injury through suppression of oxidative stress and apoptosis.

Viscosity-dependent flow reversal in a density oscillator

The density oscillator is a simple system that exhibits self-sustained oscillation. It alternately exhibits up and down flow through a pipe which connects two containers filled with fluids of different densities. However, the mechanism of the flow reversal has not yet been fully understood. From the detailed measurements, we have found that flow reversal begins with an intrusion of fluid, which is followed by rapid growth. This process is definitely sensitive to the viscosities of the fluids, and as a consequence, the critical heights leading to flow reversal are clearly viscosity dependent. These experimental results are explained by a simple model, derived by considering forces acting on a unit volume element located at the tip of the intrusion. Using this model, we can successfully explain the mechanism of flow reversal, which is the most essential process in a density oscillator.

Regulation of expression of the interleukin 6 gene: structure and function of the transcription factor NF-IL6

The interleukin 6 (IL-6) promoter is rapidly and transiently activated by other cytokines, including IL-1 and tumour necrosis factor (TNF), as well as by phorbol esters and cyclic AMP agonists. Studies using promoter mutants suggested that an IL-1-responsive element mapped within the -180 to -123 region of the IL-6 promoter. A nuclear factor (NF-IL6) that recognized a unique sequence containing an inverted repeat, ACATTGCACAATCT, was identified within the region. Direct cloning of the human NF-IL6 revealed its similarity to C/EBP, a liver- and adipose tissue-specific transcription factor. C/EBP and NF-IL6 recognize the same nucleotide sequence, but exhibit distinct patterns of expression. NF-IL6 is expressed at a low level in normal tissues, but is rapidly and drastically induced by bacterial lipopolysaccharide (LPS) or inflammatory cytokines such as IL-1, TNF and IL-6. Recently, NF-IL6 has been shown to be identical to IL-6DBP, the DNA-binding protein which is responsible for IL-6-mediated induction of several acute-phase proteins. Evidence that NF-IL6 DNA-binding activity is increased after IL-6 stimulation without increased NF-IL6 protein synthesis demonstrates the importance of post-translational modification. There are some results indicating that phosphorylation is involved in transcriptional and binding activities of NF-IL6. Taken together, these findings indicate that NF-IL6 may be an important transcription factor on the signal transduction pathways of IL-1 and IL-6.

Method for determining a coupling function in coupled oscillators with application to Belousov-Zhabotinsky oscillators

A coupling function that describes the interaction between self-sustained oscillators in a phase equation is derived and applied experimentally to Belousov-Zhabotinsky (BZ) oscillators. It is demonstrated that the synchronous behavior of coupled BZ reactors is explained extremely well in terms of the coupling function thus obtained. This method does not require comprehensive knowledge of either the oscillation mechanism or the interaction among the oscillators, both of these being often difficult to elucidate in an actual system. These facts enable us to accurately analyze the weakly coupled entrainment phenomenon through the direct measurement of the coupling function.

Nucleotide diversity of Japanese isolates of infectious hematopoietic necrosis virus (IHNV) based on the glycoprotein gene

Infectious hematopoietic necrosis virus (IHNV), a member of the genus Novirhabdovirus, causes a highly lethal disease of salmonid fish. In the present study, G gene nucleotide sequences of 9 Japanese IHNV isolates obtained from 1971 to 1996 were analyzed to evaluate the genetic diversity and compared with IHNV isolates from North America and Europe. A radial phylogenetic tree revealed 5 major clusters including 3 genogroups (U, M and L) for North American isolates and 1 genogroup for European isolates. Five Japanese isolates from 1971 to 1982 appeared in the cluster for genogroup U, while the remaining Japanese isolates from 1980 to 1996 formed a new genogroup, JRt (Japanese rainbow trout). Maximum nucleotide diversity among the Japanese isolates was 4.5%, which was greater than that within the North American isolates (3.6%), and the degree of nucleotide diversity within Japanese isolates was increased by inclusion of the genogroup JRt isolates. It was concluded that Japanese isolates shared a common source with the genogroup U of the North American isolates and that there were large divergences between Japanese isolates before and after the 1980s.

Corneal cells for regeneration

In cases of corneal epithelial stem cell deficiency where ocular surface reconstruction is required, corneal epithelial replacement using a tissue engineering technique shows great potential. Autologous cultivated corneal epithelial stem cell sheets are the safest and most reliable forms of sheet we can use for such treatment; however, they are not useful for treating bilaterally affected ocular surface disorders. In order to treat such cases, we must choose either an allogeneic cultivated corneal epithelial sheet or an autologous cultivated oral mucosal epithelial sheet. If we use the former, the threat of immunological reaction must be dealt with. Therefore, it is imperative that we have a basic understanding of the immunological aspects of ocular surface reconstruction using allogeneic tissues. When using an autologous cultivated oral mucosal epithelial sheet, a basic understanding of ocular surface epithelial biology is required as the sheet is not exactly the same as corneal epithelium.

Lactoferrin Glu561Asp facilitates secondary amyloidosis in the cornea

AIM

To elucidate the pathogenic mechanism of amyloid formation in corneal amyloidosis with trichiasis.

METHODS

Ophthalmological examination was performed in nine patients to determine secondary corneal amyloidosis with trichiasis. Congo red staining and immunohistochemistry using anti-human lactoferrin antibody were used for biopsied corneal samples. For genetic analyses, single strand conformation polymorphism (SSCP), direct DNA sequence analysis, and polymerase chain reaction (PCR) induced mutation restriction analysis (IMRA) were employed to detect lactoferrin gene polymorphism.

RESULTS

All patients had had trichiasis at least for 1 year, and all amyloid-like deposits were found in one eye with trichiasis. Ophthalmological examination revealed that eight patients showed gelatinous type of amyloid deposition and one showed lattice type of amyloid deposition. Studies of biopsied corneal samples with Congo red stain revealed positive staining just under the corneal epithelial cells. Immunoreactivity of anti-human lactoferrin antibodies was recognised in all tissues with positive Congo red staining. Lactoferrin gene analysis revealed that seven patients were heterozygotic and two were homozygotic for lactoferrin Glu561Asp. The frequency of the polymorphism in the patients was significantly different from that in 56 healthy control subjects.

CONCLUSION

Lactoferrin Glu561Asp is a key polymorphism related to facilitating amyloid formation in corneal amyloidosis with trichiasis.

Differences in heat resistance among pathogenic Yersinia enterocolitica depended on growth temperature and serotype

To gain a better understanding about the effect of growth temperature on heat resistance of Yersinia enterocolitica, we determined decimal reduction times at 60 degrees C (D60-values) for O:3; O:5,27; O:8; and O:9 strains harboring virulence plasmid coding for Yersinia outer membrane protein and experimentally virulence plasmid-deleted strains after they were grown to stationary phase at 7, 25, or 37 degrees C. Bacteria were inoculated into Trypticase soy broth and were incubated at several temperatures. D60-values of O:3; O:5,27; and O:8 strains were larger when they were grown at 37 degrees C than at 7 or 25 degrees C, despite the presence or absence of virulence plasmids. However, similar D60-values were observed in O:9 strains, despite growth at 7, 25, or 37 degrees C. The results indicate two types of Y. enterocolitica strains, growth temperature-dependent and -independent, and a Yersinia outer membrane protein that is not directly involved in growth temperature-dependent heat resistance.

The characterisation of hyalocytes: the origin, phenotype, and turnover

AIM

To determine the characterisation of hyalocytes: the origin, phenotype, and turnover in the rodent.

METHODS

To characterise the ultrastructure and distribution of hyalocytes, transmission and scanning electron microscopy was performed in rat eyes. Immunophenotypical analysis was performed by either anti-ED1 or ED2 antibodies. To examine the origin of the hyalocytes, the chimeric mice were created and were used to transplant the bone marrow (BM) cells from enhanced green fluorescent protein (EGFP) transgenic mice. The turnover of hyalocytes was examined at 0, 4, 6, 7, and 12 months after BM transplantation.

RESULTS

Hyalocytes were distributed especially in the vitreous cortex and had an irregular shape with a spherical granule. Immunophenotypical studies demonstrated that most of the hyalocytes in rat eyes expressed ED2 but not ED1. In the chimeric mice, the hyalocytes were GFP negative right after BM transplantation. Interestingly, more than 60% of hyalocytes were replaced within 4 months and approximately 90% within 7 months after BM transplantation.

CONCLUSIONS

The rodent hyalocytes were shown to express tissue macrophage marker, were derived from BM, and totally replaced within 7 months. These data provide the characterisation of hyalocytes in physiological conditions, especially their origin, distribution, and turnover, and may contribute to the better understanding of the pathogenesis of vitreoretinal disease.

Effects of acute moderate exercise on the phagocytosis of Kupffer cells in rats

AIM

This study investigated the function of Kupffer cells, and particularly their role as immunocompetent cells that come into contact with gut-derived endotoxin, in the acute exercise of rats.

METHODS

Female Fischer 344 rats were run on a treadmill at 21 m min(-1) for 60 min on a 15% grade.

RESULTS

Afterwards, the number of latex particles in the liver was higher in the exercising rats than that in resting rats and an increase in the number of latex particles phagocytosed by each Kupffer cell was noted. The plasma endotoxin concentration was significantly higher in the exercise group than in the resting rats, and the small intestine was damaged by the exercise. Plasma corticosterone and thyroxine 4 levels were unchanged. Although the number of Kupffer cells was unchanged by acute exercise, the number of CD14-positive Kupffer cells increased. Plasma liver enzyme activities were slightly increased by acute exercise, whereas plasma tumour necrosis factor-alpha was not detected.

CONCLUSION

These results suggest that moderately intense exercise increases the phagocytosis of Kupffer cells, and that it might be induced by endotoxemia of portal blood caused by intestinal mucosal lesions resulting from acute exercise.

Transplantation of cultivated autologous oral mucosal epithelial cells in patients with severe ocular surface disorders

BACKGROUND/AIMS

To determine outcomes of transplants of cultivated autologous oral epithelial cells in patients with severe ocular surface disorders.

METHODS

The eyes (n = 6) of four patients with Stevens-Johnson syndrome (three eyes) or chemical burns (three eyes) were studied. Autologous oral epithelial cells, grown for 2-3 weeks on a denuded amniotic membrane carrier in the presence of 3T3 fibroblasts, were air lifted. The resultant sheet was transplanted onto the damaged eye, and acceptance of the sheet by the corneal surface was confirmed 48 hours after surgery. The success of ocular surface reconstruction, graft survival, changes in visual acuity, and postoperative complications were assessed and the quality of the cultivated oral epithelial sheet was evaluated histologically.

RESULTS

At 48 hours after transplant, the entire corneal surface of all six eyes was free of epithelial defects indicating complete survival of the transplanted oral epithelium. Visual acuity was improved in all eyes. During follow up (mean 13.8 (SD 2.9) months), the corneal surface remained stable, although all eyes manifested mild peripheral neovascularisation.

CONCLUSIONS

Autologous oral epithelial cells grown on denuded amniotic membrane can be transplanted to treat severe ocular surface disorders.

Susceptibilities of Neisseria gonorrhoeae to fluoroquinolones and other antimicrobial agents in Hyogo and Osaka, Japan

OBJECTIVES

Decreasing susceptibility of Neisseria gonorrhoeae to fluoroquinolones has been reported in several countries. Knowledge of local N gonorrhoeae susceptibilities to various antimicrobials is important for establishing a rational treatment strategy in each region.

METHODS

Isolates of N gonorrhoeae from male urethritis patients attending four urological clinics in Hyogo and Osaka prefectures in Japan were collected during 2002. The MICs for nine antimicrobials: penicillin G, tetracycline, cefixime, ceftriaxone, levofloxacin, gatifloxacin, ciprofloxacin, moxifloxacin, and spectinomycin were determined for each isolate. All isolates were also tested for beta lactamase producing profiles.

RESULTS

Among the 87 isolates obtained, only one isolate was revealed to produce beta lactamase. MIC90 values for ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin were over 8 microg/ml, over 8 microg/ml, 4 microg/ml, and 2 microg/ml, respectively. The proportion of isolates resistant to fluoroquinolones was over 60% (ciprofloxacin, 70.1%; levofloxacin, 65.5%; gatifloxacin, 70.1%). Chromosomally mediated penicillin and tetracycline resistance was identified in 12.6% and 33.3% of the isolates. MIC90 values for cefixime and ceftriaxone and were 0.5 microg/ml and 0.0063 microg/ml. All isolates were sensitive to ceftriaxone and 90.8% of them were sensitive to cefixime. MIC90 for spectinomycin was 32 microg/ml and all isolates were sensitive to it. Fluoroquinolone resistance correlated significantly with MICs for penicillin G but not tetracycline.

CONCLUSION

Ceftriaxone and spectinomycin demonstrated lower MICs and so are recommended for N gonorrhoeae. Susceptibilities of N gonorrhoeae should be monitored periodically by region.

Ophthalmic artery blood flow in patients with internal carotid artery occlusion

AIM

To evaluate the risk factors for rubeosis iridis by colour Doppler imaging (CDI) in patients with complete internal carotid artery occlusion (ICAO).

METHODS

34 eyes of 32 consecutive patients with complete ICAO were enrolled. Using CDI, blood flow direction (forward, reverse, undetectable) in the ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary artery (SPCA) were determined. Arterial mean blood velocity (Vmean) and resistive index (RI) were calculated and correlations between the rubeosis iridis incidence and CDI parameters analysed.

RESULTS

The eyes were classified into four types according to blood flow direction: forward flow in OA, CRA, and SPCA (type 1; n = 11); reverse OA and forward CRA and SPCA flow (type 2a; n = 12); reverse OA and undetectable CRA and SPCA flow (type 2b; n = 8); undetectable flow in all three arteries (type 3; n = 3). Rubeosis iridis was seen only in type 2b and 3 eyes. Type 2b showed significantly (p<0.01) higher Vmean and lower RI values in the OA, indicating more rapid reverse flow than in type 2a eyes. Although in type 1 and 2a eyes OA flow was in opposite directions, they manifested no rubeosis iridis and no difference in the Vmean and RI values of the CRA and SPCA.

CONCLUSIONS

The classification of eyes from patients with ICAO into four types by CDI may facilitate the identification of the eyes at high risk for rubeosis iridis. Markedly diminished flow in both the CRA and SPCA may result in rubeosis iridis, regardless of OA flow direction.

An increase in damaged hepatocytes in rats after high intensity exercise

AIM

The purpose of this study was to clarify the effect of various exercise intensities on damage to the hepatic parenchymal cells.

METHODS

Male Wistar rats were subjected to forced exercise by treadmill running at 60 and 80% of maximum oxygen uptake (VO2max) for 120 min, sacrificed immediately and 6 h after the exercise, and then the perfused liver was stained with trypan blue solution to estimate the local damage to the liver.

RESULTS

Although there were no significant increases in damaged hepatic cells immediately after both intensities of exercise, these damaged cells, in particular pericentral hepatocytes, significantly increased at 6 h after the exercise at the 80% VO2max. However, there were no significant increases in the serum glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) activities immediately and 6 h after both intensities of exercise.

CONCLUSIONS

These results suggested that hepatocytes suffered damage after high-intensity exercise, although these histochemical findings in the liver were not observed immediately after the exercise. In addition, in the case of physical activity, there might not be an intimate relationship between the release of enzyme as a hepatic functional biomarker and hepatocyte damage.