Suppression of experimental autoimmune uveitis in guinea-pigs by inhibition of phospholipase A2

Retinal S-antigen mixed with complete Freund's adjuvant was used to induce experimental autoimmune uveitis (EAU) in guinea-pigs. Guinea-pigs receiving no treatment, was compared with test animals which received topically and systemically administered KLM-583B, a phospholipase A2 (PLA2) inhibitor, or subcutaneous (sub. cut) and topical corticosteroid treatment, as well as a test group which received cyclosporin A suc. cut. The best clinical suppression of EAU was obtained in the group treated suc. cut with KLM-538B. Steroids also suppressed the inflammation in the eyes but was not as effective as KLM-583B or cyclosporine A. PLA 2 activity in the aqueous humour and the myeloperoxidase (MPO) levels measured from iris-ciliary body were significantly lower in the groups treated suc. cut. with KLM-583B or cyclosporin A. Guinea-pigs treated suc. cut. with KLM-583B and cyclosporin A had the lowest antiserum titres to retinal S-antigen.

Differences in retinal neovascular tissue and vitreous humour in patients with type 1 and type 2 diabetes

AIMS

The aim of the study was to evaluate the histopathology of neovascular tufts and vitreous samples collected from patients with diabetes.

METHODS

Vitreous samples and neovascular tufts were collected from patients with type 1 (n = 13) and (n = 17) type 2 diabetes with proliferative retinopathy, and from controls with a macular hole (n = 5). Neovessels were analysed using immunohistochemistry and vitreous samples with an enzyme-linked immunosorbent assay (ELISA). The main outcome measure was to examine differences in the levels of growth factors in patients with type 1 and type 2 diabetes with proliferative retinopathy.

RESULTS

Vascular endothelial growth factor (VEGF)-A was most strongly present in the samples from patients with type 1 diabetes. In type 2 diabetes, VEGF-D was more abundantly present than in type 1 diabetes. Angiopoietin (ANG)-2 was also abundantly present. Macrophages and nuclear factor kappa B (NFkappaB) were found, indicating the presence of an inflammatory process in the neovascular tissues.

CONCLUSIONS

VEGF-A and ANG-2 are equally important in the neovascular process in both type 1 and type 2 diabetes. VEGF-D is abundantly present in type 2 diabetes. In order to achieve better control of diabetic retinopathy, it might be beneficial to develop treatments that prevent the actions of ANG-2 and VEGF-D.

In vitro biocompatibility of degradable biopolymers in cell line cultures from various ocular tissues: direct contact studies

Synthetic biodegradable polymers have many potential therapeutic applications. In ophthalmology, biodegradable polymers have been used as viscoelastic agents and surgical implants. Other potential applications include controlled release of drugs and growth factors, gene therapy, and tissue engineering. In the present study, in vitro biocompatibility of three biodegradable polymers, 50:50 PDLGA, 85:15 PDLGA, and Inion GTR membrane was evaluated in comparison to tissue culture polystyrene by investigating cell proliferation and potential acute toxicity by the WST-1 cytotoxicity/cell proliferation test, the ATP test, and the lactate dehydrogenase (LDH) test. Evaluations were conducted with cell line cultures from various ocular tissues, human corneal epithelial cells (HCE), rabbit stromal fibroblasts (SIRC), bovine corneal endothelial cells (BCE), human conjunctival epithelial cells (IOBA-NHC), and human retinal pigment epithelial cells (ARPE-19) by direct contact studies by plating the cells on the polymer film specimens in 96-wells. The proliferation results show that cell lines from various ocular tissues attached and grew on PDLGA 50:50, PDLGA 85:15, and Inion GTR membrane. Cytotoxicity experiments with the LDH and ATP tests showed no or extremely slight toxic adverse effects. These polymers have potential to be used as scaffolds in cell transplantation devices or as surgical implants.

Ophthalmic timolol: plasma concentration and systemic cardiopulmonary effects

Timolol maleate is a non-selective beta-adrenoceptor antagonist currently used mainly as an ocular preparation for the treatment of glaucoma and ocular hypertension. Despite the topical administration, ophthalmic timolol causes systemic adrenergic beta-blocking because of absorption from the eye into the systemic circulation. Gel formulations of ophthalmic timolol have been developed to reduce systemic absorption and adverse effects in comparison with conventional aqueous solution formulations. Timolol is metabolized by the polymorphic cytochrome P450 2D6 enzyme (CYP2D6). The changes in heart rate (HR) are the most striking effects of the systematically absorbed fraction of ophthalmic timolol, with 0.5 % aqueous formulations presenting larger effects than 0.1 % hydrogel formulations, especially during exercise. Plasma levels of ophthalmic timolol correlate with the changes in HR. Neither 0.5 % aqueous nor 0.1 % hydrogel formulations of timolol have exerted noteworthy effects on systolic (SAP) or diastolic (DAP) arterial pressures, probably because of a compensatory increase in systemic vascular resistance due to the attenuation of HR. Ophthalmic timolol does not exert remarkable effects on pulmonary parameter peak expiratory flow (PEF) and forced expiratory volume in 1 s (FEV1) in non-asthmatic patients. CYP2D6 activity is clearly associated with the pharmacokinetic parameters, particularly when 0.5 % aqueous solution of timolol is used: peak plasma concentration, elimination half-life and area-under-the-curve are highest in CYP2D6 poor metabolizers. Finally, since there is a correlation between the plasma level of timolol and several haemodynamic effects - especially HR in the state of elevated beta-adrenergic tonus - the CYP2D6 poor metabolizers may be more prone to bradycardia during treatment with (aqueous) ophthalmic timolol.

Overexpression of VEGF-A induces neovascularization and increased vascular leakage in rabbit eye after intravitreal adenoviral gene transfer

AIM

The aim of this study was to determine dose-response effects of vascular endothelial growth factor A as delivered using an adenoviral vector on vascular growth and pathological changes in the rabbit eye. Moreover, we wanted to develop a large animal model for angioproliferative diseases in the eye.

METHODS

Seventeen New Zealand White rabbits were injected with adenoviral vascular endothelial growth factor-A (AdVEGF-A) intravitreally with different doses (10(9)-10(11) vp). Controls were injected with an empty virus (AdCMV). Some animals had a combination of AdVEGF-A and AdsKDR (a soluble form of the VEGF receptor-2). Animals were killed 6 days after the gene transfer. On the basis of these results, 14 rabbits were injected intravitreally with AdVEGF-A or adenoviral LacZ (AdLacZ) with 10(10) vp in a volume of 0.1 mL. Animals were killed 3, 6, 14 and 28 days after the gene transfer, eyes were removed and analysed histologically.

RESULTS

In enzyme-linked immunosorbent assay (ELISA) analysis, human VEGF-A was present in vitreous humour in all VEGF-A transduced eyes. The amount of VEGF-A showed a dose-dependent increase with the AdVEGF-A dose and was the highest 6 days after the gene transfer. Histologic analyses revealed an increased capillary area and density in the AdVEGF-A eyes when compared with the AdLacZ eyes (P < 0.05). In the AdVEGF-A/AdsKDR eyes the average capillary area was not increased compared with AdLacZ eyes.

CONCLUSION

This model could be useful for large animal studies regarding the pathogenesis of neoangiogenesis and for the development of new therapeutic strategies for angioproliferative diseases of the eye. Our results establish the key role of VEGF-A in the induction of neovascularization and pathological changes in the rabbit eye.

Mechanisms dependent on tryptophan catabolism regulate immune responses in primary Sjögren's syndrome

To investigate the possible role of tryptophan metabolism in immune regulation of primary Sjögren's syndrome (pSS) the serum concentrations of tryptophan and its metabolite kynurenine were measured by reverse-phase high-performance liquid chromatography (HPLC) in 103 patients with pSS, 56 patients with sicca symptoms and 309 healthy blood donors. The kynurenine per tryptophan ratio (kyn/trp), which reflects the activity of the indoleamine-pyrrole 2,3-dioxygenase (IDO) enzyme involved in tryptophan catabolism, was calculated. Both female and male patients with pSS had significantly higher serum kynurenine concentrations and kyn/trp than subjects with sicca symptoms or healthy blood donors. The median (quartile range) concentration of kynurenine in female patients with pSS was 2.41 micromol/l (1.86-3.26) compared with 1.85 micromol/l (1.58-2.38, P < 0.0001) in subjects with sicca symptoms and 1.96 micromol/l (1.65-2.27, P < 0.0001) in healthy blood donors. Their kyn/trp x 1000 was 34.0 (25.1-44.3) compared with 25.3 (21.1-31.5, P < 0.0001) in subjects with sicca symptoms and 24.3 (21.0-28.9, P < 0.0001) in healthy blood donors. Female pSS patients with high IDO activity (kyn/trp x 1000 > or = 34.0) had significantly higher ESR, serum C-reactive protein, serum IgA and serum beta-2 microglobulin concentrations as well as higher serum creatinine levels, and they had positive antinuclear antibodies more frequently and presented with more American-European consensus group criteria than those with low IDO activity (kyn/trp x 1000 < 34.0). These data suggest that mechanisms dependent on tryptophan catabolism regulate immune responses in pSS. Tryptophan degradation is enhanced in patients with pSS, and high IDO activity is associated with severity of pSS.

Bone defect repair in immobilization-induced osteopenia: a pQCT, biomechanical, and molecular biologic study in the mouse femur

The present study was carried out to determine whether immobilization-induced (Im) osteopenic bone possesses the same reparative capacity as normal healthy bone. Furthermore, the effects of mechanical loading versus immobilization on bone defect healing were studied. Three-week cast-immobilization was used to induce local osteopenia in mice. A standardized metaphyseal bone defect of the distal femur was created unilaterally both in immobilization-induced (Im) osteopenic mice and in nonimmobilized (Mo) age-matched control animals. After creation of the bone defect, the animals in both groups were further divided into two groups: 3-week cast-immobilization (Im-Im and Mo-Im) groups, and unrestricted weight-bearing (Im-Mo and Mo-Mo) groups. The healing process was followed up to 3 weeks using RNA analysis, histomorphometry, biomechanical testing, and pQCT measurements. At 3 weeks of healing without immobilization, bone mineral density (BMD), as well as bone bending stiffness and strength were higher in normal (Mo-Mo) than in osteopenic (Im-Mo) bone. Although the levels of mRNAs characteristic to chondrocytes (Sox9 and type II collagen), hypertrophic chondrocytes (Type X collagen), osteoblasts (type I collagen and osteocalcin), and osteoclasts (cathepsin K) during the bone defect healing exhibited similarities in their expression profiles, mechanical loading conditions also caused characteristic differences. Mechanical loading during healing (Mo-Mo group) induced stronger expression of cartilage- and bone-specific genes and resulted in higher BMD than that seen in the cast-immobilized group (Mo-Im). In biomechanical analysis, increased bending stiffness and strength were also observed in animals that were allowed weight-bearing during healing. Thus, our study shows that bone healing follows the same molecular pathway both in osteopenic and normal bones and presents evidence for reduced or delayed regeneration of noncritical size defects in immobilization-induced osteopenic bone.

A new index to measure the accuracy of refractive operations

PURPOSE

To create a new index to help evaluate the accuracy of the outcome of refractive surgery.

METHODS

By combining information given by the cross-cylinder form of surgically induced refractive change (SIRC) and basic methods of vector analysis, we constructed a new index which serves as a tool to evaluate postoperatively the changes achieved by refractive surgery. This new index gives easily understandable numerical values and takes into account changes in both spherical refraction and astigmatism. We demonstrated the use of this index in two study populations consisting of 20 consecutive eyes operated on using two different lasers, Meditec MEL60 and MEL70, respectively.

RESULTS

Although postoperative uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) were better in the MEL70 group, the difference of photoefractive keratectomy (PRK) for combined astigmatism and myopia was not statistically significant. Comparison of the changes in refraction achieved by the two lasers indicated that the MEL60 was more accurate; this was also seen when comparing the total index of error between the two groups.

CONCLUSIONS

We suggest the use of this total index of error (TIE) in clinical praxis because it provides an easy and accurate method of evaluating the accuracy of refractive operations. These inaccuracies might otherwise go unnoticed if the basic values only (e.g. UCVA, BCVA and haze) were used in postoperative evaluation.

The Finnish evidence-based guideline for open-angle glaucoma

In most patients, chronic open-angle glaucoma is a slowly progressive disease. Eyes with very high intraocular pressure (IOP > 30 mmHg) represent an exception to this and should be treated and followed extremely intensively. As lowering IOP is, so far, the only means of treating glaucoma, the majority of research reports deal with the IOP-lowering effect of the treatment. The primary goal of treatment, however, is to prevent glaucomatous damage to the structures and function of the eye. The effectiveness of treatment is monitored with optic disc and retinal nerve fibre layer imaging and with visual field examinations. If the glaucomatous changes are progressing, more effective treatment should be given. In the course of follow-up, it should be noted that the changes in the optic nerve structure and function appear and progress at different time-points with delays of up to several years. The assessment of abnormalities is dependent on the examination method and requires a great deal of experience on the part of the examiner. The important risk factors in glaucoma are elevated IOP (even if IOP is within normal range in half of patients ), age, positive family history, exfoliation, race and myopia.

Analysis of lapine cartilage matrix after radiosynovectomy with holmium-166 ferric hydroxide macroaggregate

OBJECTIVE

To study the short and long term effects of radiosynovectomy on articular cartilage in growing and mature rabbits.

METHODS

The articular cartilage of the distal femurs of rabbits was examined four days, two months, and one year after radiosynovectomy with holmium-166 ferric hydroxide macroaggregate ([(166)Ho]FHMA). Arthritic changes were evaluated from histological sections by conventional and polarised light microscopy, and glycosaminoglycan measurements using safranin O staining, digital densitometry, and uronic acid determination. Proteoglycan synthesis was studied by metabolic [(35)]sulphate labelling followed by autoradiography, and electrophoretic analysis of extracted proteoglycans. Northern analyses were performed to determine the mRNA levels of type II collagen, aggrecan, and Sox9 in cartilage samples.

RESULTS

Radiosynovectomy had no major effect on the histological appearance of articular cartilage in mature rabbits, whereas more fibrillation was seen in [(166)Ho]FHMA radiosynovectomised knee joints of growing rabbits two months after treatment, but not after one year. Radiosynovectomy did not cause changes in the glycosaminoglycan content of cartilage or in the synthesis or chemical structure of proteoglycans. No radiosynovectomy related changes were seen in the mRNA levels of type II collagen, whereas a transient down regulation of aggrecan and Sox9 mRNA levels was seen in young rabbits two months after [(166)Ho]FHMA radiosynovectomy.

CONCLUSIONS

[(166)Ho]FHMA radiosynovectomy caused no obvious chondrocyte damage or osteoarthritic changes in mature rabbits, but in growing rabbits some transient radiation induced effects were seen--for example, mild cartilage fibrillation and down regulation of cartilage-specific genes.

Cardiovascular effects of ophthalmic 0.5% timolol aqueous solution and 0.1% timolol hydrogel

The objective of this randomized, double-masked, cross-over study was to compare the cardiovascular effects of two glaucoma formulations, ophthalmic 0.5% timolol aqueous solution and 0.1% timolol hydrogel. Twenty-four young healthy subjects received for 2 weeks either twice daily 0.5% timolol solution or once daily 0.1% timolol hydrogel. Heart rate (HR), blood pressure, atrio-ventricular conduction (PR interval), corrected QT time (QTc) and heart rate variability (HRV) were measured in supine position and during head-up tilted position. The mean peak concentrations of timolol in plasma were significantly higher after administration of 0.5% aqueous solution than after 0.1% hydrogel. A 0.5% timolol aqueous solution decreased HR on average by 3 bpm in supine position and by 7 bpm in head-up tilted position while no significant effects were observed with 0.1% timolol hydrogel. During tilt test HR was significantly lower after administration of timolol aqueous solution than after timolol hydrogel (mean +/- SD, 77 +/- 11 bpm versus 86 +/- 13 bpm, P < 0.05). Timolol aqueous solution slightly decreased QTc during tilt (5.9 +/- 5.6 ms, P < 0.01). During tilt tests, timolol aqueous solution slightly increased atrio-ventricular conduction (7.2 ms, P = 0.02). No significant differences were found in HRV. These results indicate that in healthy volunteers, ophthalmic 0.5% timolol aqueous solution produces more pronounced cardiac beta-blocking effects than 0.1% timolol hydrogel.

Evaluation of the cytotoxicity of selected systemic and intravitreally dosed drugs in the cultures of human retinal pigment epithelial cell line and of pig primary retinal pigment epithelial cells

The cytotoxicity of the selected systemic and intravitreally dosed drugs tamoxifen, toremifene, chloroquine, 5-fluorouracil, gentamicin and ganciclovir was studied in retinal pigment epithelium (RPE) in vitro. The cytotoxicity was assayed in the human RPE cell line D407 and the pig RPE cell culture using the WST-1 test, which is an assay of cell proliferation and viability. The effects of experimental conditions on the WST-1 test (cell density, serum content in the culture medium, the exposure time) were evaluated. The EC50 values in tamoxifen-treated D407 cells ranged between 6.7 and 8.9 micromol/l, and in pig RPE cells between 10.1 and 12.2 micromol/l, depending on the cell density used. The corresponding values for toremifene were 7.4 to 11.1 micromol/l in D407 cells and 10.0 to 11.6 micromol/l in pig RPE cells. In chloroquine-treated cells, the EC50 values were 110.0 micromol/l for D407 cells and 58.4 micromol/l for pig RPE cells. Gentamicin and ganciclovir did not show any toxicity in micromolar concentrations. The exposure time was a significant factor, especially when the drug did not induce cell death, but was antiproliferative (5-fluorouracil). Serum protected the cells from the toxic effects of the drugs. Both cell cultures were most sensitive to tamoxifen and toremifene, and next to chloroquine. The drug toxicities obtained in the present study were quite similar in both cell types; that is, the pig RPE cells and the human D 407 cell line, despite the differences in, for example, the growth rate and melanin contents of the cell types. Owing to the homeostatic functions important for the whole neuroretina, RPE is an interesting in vitro model for the evaluation of retinal toxicity, but, in addition to the WST-1 test, more specific tests and markers based on the homeostatic functions of the RPE are needed.

Activation of chondrogenesis in response to injury in normal and transgenic mice with cartilage collagen mutations

OBJECTIVE

The aim of this report is to describe and discuss the reparative capacity of articular cartilage by focusing on similarities and differences in the activation of chondrogenesis in adult bone and cartilage in response to injury.

DESIGN

The present report describes three different models of skeletal repair in the mouse. Two of the models deal with bone healing, where the activation of chondrogenesis and formation of callus tissue is greatly dependent on the rigidity of fixation. The third comprises two transgenic mouse models for osteoarthritis where dominant negative mutations in cartilage-specific genes disturb the structural integrity of the cartilage collagen fibrils.

RESULTS

Molecular biologic and immunohistochemical analyses demonstrated that activation of chondrogenesis in healing fractures, i.e., activation and maintenance of the chondrocyte phenotype was preceded by increased production and nuclear accumulation of transcription factor SOX9. A similar, albeit smaller, chondrogenic response was observed during healing of biomechanically stable metaphyseal bone defects. In degenerating articular cartilage of transgenic mice, however, the production of cartilage-specific collagen types and SOX9 was markedly reduced upon aging which probably explains why repair of cartilage defects was insufficient.

CONCLUSION

Understanding of the molecular mechanisms involved in successful and unsuccessful activation of chondrogenesis during skeletal repair, will provide information needed for enhancement of the chondrocytic response at sites of skeletal repair. Our data also demonstrates that specific effector molecules can be efficiently introduced into chondrocytes and their precursors by adenovirus-mediated gene transfer.

A cost study of teleconsultation for primary-care ophthalmology and dermatology

Teleconsultations were performed between a health centre in a small Finnish town and a university hospital 55 km away. Telemedicine consultations were carried out with a total of 42 patients suffering from various eye and skin disorders. We evaluated the costs of the teleconsultations in the health centre and the conventional alternative of the patient travelling to the hospital. The cost of conventional consultations, which was not affected by the patient workload, was EU126 per patient for ophthalmology and EU143 per patient for dermatology. The cost of the teleconsultations per patient decreased as the number of patients increased. There were cost savings in relation to teleconsultations when the annual numbers of patients were more than 110 in ophthalmology and 92 in dermatology. Benefits and savings achieved through teleconsultations mainly consisted of reduced transportation costs and reduced paperwork both at the health centre and at the university hospital, as well as time savings for the patient. Another important benefit was improved medical education. The present study shows that teleconsultations can be performed in a cost-effective way in a relatively small health centre.

Accelerated up-regulation of L-Sox5, Sox6, and Sox9 by BMP-2 gene transfer during murine fracture healing

Fracture repair is the best-characterized situation in which activation of chondrogenesis takes place in an adult organism. To better understand the mechanisms that regulate chondrogenic differentiation of mesenchymal progenitor cells during fracture repair, we have investigated the participation of transcription factors L-Sox5, Sox6, and Sox9 in this process. Marked up-regulation of L-Sox5 and Sox9 messenger RNA (mRNA) and smaller changes in Sox6 mRNA levels were observed in RNAse protection assays during early stages of callus formation, followed by up-regulation of type II collagen production. During cartilage expansion, the colocalization of L-Sox5, Sox6, and Sox9 by immunohistochemistry and type II collagen transcripts by in situ hybridization confirmed a close relationship of these transcription factors with the chondrocyte phenotype and cartilage production. On chondrocyte hypertrophy, production of L-Sox5, Sox9 and type II collagen were down-regulated markedly and that of type X collagen was up-regulated. Finally, using adenovirus mediated bone morphogenetic protein 2 (BMP-2) gene transfer into fracture site we showed accelerated up-regulation of the genes for all three Sox proteins and type II collagen in fractures treated with BMP-2 when compared with control fractures. These data suggest that L-Sox5, Sox6, and Sox9 are involved in the activation and maintenance of chondrogenesis during fracture healing and that enhancement of chondrogenesis by BMP-2 is mediated via an L-Sox5/Sox6/Sox9-dependent pathway.

Accelerated turnover of metaphyseal trabecular bone in mice overexpressing cathepsin K

This study is based on a hypothesis that overexpression of an osteoclast enzyme, cathepsin K, causes an imbalance in bone remodeling toward bone loss. The hypothesis was tested in transgenic (TG) mice harboring additional copies of the murine cathepsin K gene (Ctsk) identifiable by a silent mutation engineered into the construct. For this study, three TG mouse lines harboring 3-25 copies of the transgene were selected. Tissue specificity of transgene expression was determined by Northern analysis, which revealed up to 6-fold increases in the levels of cathepsin K messenger RNA (mRNA) in calvarial and long bone samples of the three TG lines. No changes were seen in the mRNA levels of other osteoclast enzymes, indicating that the increase in cathepsin K mRNA was not a reflection of activation of all osteoclast enzymes. Immunohistochemistry confirmed that cathepsin K expression in the TG mice was confined to osteoclasts and chondroclasts. Histomorphometry revealed a significantly decreased trabecular bone volume (BV), but, surprisingly, also a marked increase in the number of osteoblasts, the rate of bone turnover, and the amount of mineralizing surface (MS). However, monitoring of bone density in the proximal tibias of the TG mice with peripheral quantitative computed tomography (pQCT) failed to reveal statistically significant changes in bone density. Similarly, no statistically significant alterations were observed in biomechanical testing at the age of 7 months. The increases in parameters of bone formation triggered by increased cathepsin K expression is an example of the tight coupling of bone resorption and formation during the bone-remodeling cycle.

Visual tests for measuring the picture quality of teleconsultations for medical purposes

Telemedicine provides a new way of delivering medical services. The good quality of the picture is, however, essential for a proper and reliable teleconsultation, especially in the cases when visual information about the patient's physical condition is of great importance as in ophthalmology and dermatology. Therefore real-time telemedical applications need standards for these procedures, e.g. minimum requirements for resolution, as well as contrast and color discrimination. The present study was carried out to test these parameters in a real environment. A panel of different resolution, contrast sensitivity and color discrimination tests was carried out for five test persons via PictureTel videoconference system by ISDN 128 kbit/s line speed and in a normal way. The good color discrimination of the teleconsultation system makes it possible to use the system in the evaluation of different skin lesions and exemas. However, the poor resolution and especially poor contrast sensitivity makes the use of the equipment valueless in the evaluation of diseases where the diagnoses are based on the discrimination of small details, like the biomicroscopical analysis of inflammatory cells in the aqua's humor in cases of intraocular inflammation. The authors are suggesting a simple panel of tests to optimize and standardize these parameters.

Induction of periosteal callus formation by bone morphogenetic protein-2 employing adenovirus-mediated gene delivery

Although the chondrogenic response of periosteum is well established in healing fractures, the mechanisms mediating the proliferation and differentiation of periosteal chondroprogenitor cells are poorly understood. In the present study we demonstrate that bone morphogenetic protein-2 (BMP-2), introduced by adenovirus-mediated gene transfer, alone is capable of inducing callus formation at the site of periosteal injection. Both immunohistochemistry and Northern analysis demonstrated activation of type II collagen production between days 4 and 7 after the injection, followed by activation of type X collagen expression. The activation of chondrogenesis was associated with increased expression of L-Sox5 and Sox9, suggesting that the BMP-2 effect is mediated via Sox proteins. This capacity of adenovirus-mediated overproduction of BMP-2 to induce chondrogenesis (and subsequent endochondral ossification) should be useful for tissue engineering of cartilage and bone.

A metaphyseal defect model of the femur for studies of murine bone healing

A bone defect model was developed in the distal metaphysis of the femur for studies on bone healing in the mouse. The circular defect involving 20% of the bone circumference resulted in a 34% reduction in the bending moment compared to intact bone. The healing process was followed using histomorphometry, peripheral quantitative computed tomography (pQCT), biomechanical testing, and molecular biological analyses. Histologically, healing of the defect was characterized by filling of the medullary cavity with trabecular new bone during the first week of healing, and by closing of the cortical window by 6 weeks. Small areas of periosteal chondrogenesis were frequently observed during defect healing. In pQCT, bone mineral content (BMC) of the defect area approached that of intact control bone already by 3 weeks, reflecting the production of trabecular bone. Similarly, the bending strength and stiffness of the healing femur reached the level of intact control femur already at 3 weeks. Bone formation and remodeling was followed by Northern analyses, which demonstrated elevated mRNA levels for bone components (type I collagen and osteocalcin), and for osteoclastic enzymes (cathepsin K, matrix metalloproteinase-9, and tartrate-resistant acid phosphatase) throughout the healing period. Finally, the applicability of the defect model for gene therapy experiments was tested using adenovirus-mediated transfer of the LacZ reporter gene. Both histochemistry and mRNA analyses demonstrated that the gene was expressed in the repair tissue with the highest expression during the first week of healing. The present model thus provides a standardized environment for studies on induction and remodeling of trabecular new bone in normal and genetically engineered mice.

Expression of cathepsins B, H, K, L, and S and matrix metalloproteinases 9 and 13 during chondrocyte hypertrophy and endochondral ossification in mouse fracture callus

Fracture repair provides an interesting model for chondrogenesis and osteogenesis as it recapitulates in an adult organism the same steps encountered during embryonic skeletal development and growth. The fracture callus is not only a site of rapid production of cartilage and bone, but also a site of extensive degradation of their extracellular matrices. The present study was initiated to increase our understanding of the roles of different proteolytic enzymes, cysteine cathepsins B, H, K, L, and S, and matrix metalloproteinases (MMPs) 9 and 13, during fracture repair, as this aspect of bone repair has previously received little attention. Northern analysis revealed marked upregulation of cathepsin K, MMP-9, and MMP-13 mRNAs during the first and second weeks of healing. The expression profiles of these mRNAs were similar with that of osteoclastic marker enzyme tartrate-resistant alkaline phosphatate (TRAP). The changes in the mRNA levels of cathepsins B, H, L, and S were smaller when compared with those of the other enzymes studied. Immunohistochemistry and in situ hybridization confirmed the predominant localization of cathepsin K and MMP-9 and their mRNA in osteoclasts and chondroclasts at the osteochondral junction. MMP-13 was present in osteoblasts and individual hypertrophic chondrocytes near the cartilage-bone interphase. In cartilaginous callus, the expression of cathepsins B, H, L, and S was mainly related to chondrocyte hypertrophy. During bone remodeling both osteoblasts and osteoclasts contained these cathepsins. The present data demonstrate that degradation and remodeling of extracellular matrices during fracture healing involves activation of MMP-13 production in hypertrophic chondrocytes and osteoblasts, and cathepsin K and MMP-9 production in osteoclasts and chondroclasts.

A feasibility study of realtime teledermatology in Finland

We conducted a feasibility study of teleconsultation in dermatology using low-cost equipment. Patients and their general practitioners took part in consultations from the Primary Health Care Centre in Ikaalinen with a dermatologist 55 km away at the Tampere University Hospital (TAUH). Consultations were performed using standard commercial videoconferencing equipment, a modified document camera and a dermatoscope. A single ISDN line (128 kbit/s) was used for the connection. During the eight months of the study, 25 patients participated in a teledermatology consultation. Their mean age was 45 years (range 4-92). The average time the patient spent in travelling to the videoconsultation (i.e. one way) was 24 min (range 5-65 min). The mean time spent in the teleconsultation was 15 min (range 5-30 min). After the teleconsultation, patients' treatments changed in 19 cases (76%), diagnoses were changed in 13 cases (52%) and 18 patients (72%) did not need to go to the TAUH. The equipment was generally reliable and easy to use. However, the dermatoscope was not very useful and only one of the consultations relied mainly on it. The cost of the teleconsultations for the 18 patients who avoided travel to the TAUH was FM18,627. The total costs for the 18 conventional consultations in the TAUH would have been FM18,034. The main economic benefits of the videoconferencing were attributable to the reduced travelling and hospital costs. The economic benefits of medical education were more difficult to quantify.

Teleconsultations between general practitioners and ophthalmologists in Finland

We carried out a study of the value of videoconferencing in consultations between general practitioners (GPs) and ophthalmologists in Finland. We used ISDN lines (128 kbit/s) between the Primary Health Care Centre in Ikaalinen and the ophthalmology clinic at the Tampere University Hospital (TAUH). Questionnaires covering both clinical and technical matters were given to patients and doctors after the consultation. During the 10-month study, consultations were carried out successfully for 23 of 24 patients (96%). Most consultations (84%) took less than 15 min. If we had not had this system, the GP would have made 21 referrals to an ophthalmologist. After teleconsultation, six patients were sent to the TAUH, so the system saved 15 referrals. Twenty-two patients (92%) thought that videoconferencing was a reliable tool for GPs. Our system proved to be a valuable and reliable tool for the GPs in ophthalmology consultations and continuing education.

Expression profiles of mRNAs for osteoblast and osteoclast proteins as indicators of bone loss in mouse immobilization osteopenia model

An experimental mouse model for disuse osteopenia was developed using unilateral cast immobilization. Analysis of the distal femurs and proximal tibias by quantitative histomorphometry revealed significant osteopenia within 10-21 days of immobilization. At 3 weeks, bone loss was also demonstrated with peripheral quantitative computed tomography as diminished bone mineral content and as concomitant reduction in the cross-sectional moment of inertia. These structural and geometrical alterations resulted in decreased strength of the distal femurs tested by cantilever bending. Analysis of the underlying cellular and molecular mechanisms of bone loss revealed a rapid increase in bone resorption within 3 days of immobilization. The mRNA levels for cathepsin K, matrix metalloproteinase-9, and tartrate resistant acid phosphatase were all significantly increased during the 21-day immobilization period, but with different expression profiles. These increases were paralleled by an increased number of osteoclasts as measured by histomorphometry. By day 6 of immobilization, the balance of bone turnover was further shifted toward net bone loss as the mRNA levels for major bone components (type I collagen and osteocalcin) were decreased. In histomorphometric analysis this was observed as reduced rates of mineral apposition and bone formation after 10 days of immobilization. The results of this study demonstrate that immobilization has a dual negative effect on bone turnover involving both depressed bone formation and enhanced bone resorption.

Clinical follow up study of 87 patients with sicca symptoms (dryness of eyes or mouth, or both)

OBJECTIVE

To assess the prognosis of patients with sicca symptoms and to identify the clinical and immunological factors that most sensitively predict the later development of primary Sjögren's syndrome (SS) or other connective tissue diseases.

METHODS

Eighty seven patients (72 female, 15 male) with sicca symptoms were re-evaluated after a median follow up time of 11 years (range 8-17). The clinical examination included ophthalmological examination (Schirmer's test, break up time and Rose-Bengal staining). Labial salivary gland biopsy was performed and histological findings graded according to the Chisholm-Mason scale. The immunoserological tests included determination of rheumatoid factor (RF), antinuclear antibodies (ANA), anti-extractable nuclear antigen-antibodies (ENA), serum immunoglobulins IgA, IgG, and IgM, and serum beta2-microglobulin (beta2m).

RESULTS

At follow up 31 patients (36%) fulfilled modified Californian criteria (salivary flow measurements were not performed and Chisholm-Mason grades 3-4 were regarded as diagnostic histological findings) for possible or definite SS. Likewise, a significant progression of the histological findings was observed. Labial salivary gland re-biopsy was performed in 42 patients with grade 0-2 findings at baseline, progression to grades 3-4 being observed in 21 (50%) at follow up. The patients who later developed SS were at baseline significantly older (mean (SD) 52 (9) v 44 (14) years, p</=0.005) compared with those not fulfilling the SS criteria at follow up; they also had significantly higher serum beta2m (p</=0.0005) and IgG concentrations (p</=0.005), and they had positive ANA more frequently (p</=0.01).

CONCLUSION

These results suggest that high age, increased values of serum beta2m, ANA positivity and increased concentrations of serum IgG, might be useful indicators for the subsequent development of SS in patients with sicca symptoms. The prognosis of patients with these symptoms was favourable, and the clinical course was benign even in the 36% of patients who developed SS. No cases of lymphoma were observed.

The expression of tenascin-X in developing and adult rat and human eye

Tenascin-X has been studied in developing and adult rat eye and in foetal and adult human eyes, using immunohistochemistry and frozen sections. The data were compared with the distribution of tenascin-C. The immunoreactivity for tenascin-X was seen in a basement membrane-like feature in different structures of embryonic (E) day 16-17 rat eyes. Postnatal (P) day 2 and older rat eyes showed immunoreactivity for tenascin-X in different connective tissues. In the epithelial basement membrane zone of the cornea, immunostaining was positive in P5 eyes, negative in P10 and P15 eyes and again positive in P30 and adult eyes. In the 20-week-old human foetus, immunoreactivity for the tenascin was seen in the posterior parts of the conjunctival stroma adjacent to the sclera and in a basement membrane-like fashion in anterior conjunctiva. In the adult human eye, immunoreactivity for tenascin-X was seen in the anterior one-third stroma of cornea as thin fibrils, in the stroma of the limbus and conjunctiva, and in blood vessels. Immunostaining for tenascin-C was seen in the posterior aspect of the further cornea, and in mesenchyme adjacent to cornea in E1617 rat eyes. Corneal keratocytes and Descemet's membrane showed immunoreactivity for tenascin-C in P2-P15 rat eyes. Sclera and the junction of the cornea, and sclera expressed tenascin-C in P2 and older rat eyes. In human foetal eyes, immunostaining for tenascin-C was seen in the anterior parts of the corneal stroma, in the basement membrane zone and Bowman's membrane of the corneal epithelium, in the posterior one-fifth of the corneal stroma and the sclera starting from the junction of the cornea and sclera. In normal human adult eyes, immunostaining for tenascin-X was seen in the anterior one-third stroma of cornea, in the stroma of limbus and conjunctiva, and in blood vessels. The association of tenascin-X and basement membranes in early development evokes a question of its potential function in the development of the basement membrane. The results also suggest the association of tenascin-X with connective tissue development as well as the association of tenascin-C with the migration of keratocytes during the development of the corneal stroma.

Binding of CGRP analogs and their effect on adenylate cyclase activity in porcine iris-ciliary body

The structure-activity relationship of the calcitonin gene-related peptide (CGRP) in the porcine iris-ciliary body was studied using different CGRP analogs. The receptor binding affinity is located mainly in the carboxyterminal end of the CGRP peptide while the ability to stimulate adenylate cyclase (AC) enzyme is mainly in the aminoterminal end of the peptide. The binding of CGRP analogs was also found to be temperature-dependent. Changes in the alpha-helical region or in the beta-turn, as well as replacements of threonine-4, asparagine-25 or asparagine-26, reduce the binding affinity already at +4 degrees C. Truncated aminoterminus, changes in the loop region between cysteines 2 and 7, and especially in threonine 6, have for their part an important role in maintaining AC-stimulating activity.

Photorefractive Keratectomy for -1.25 to -25.00 Diopters of Myopia

BACKGROUND

We evaluated prospectively the efficacy, predictability, stability, and safety of photorefractive keratectomy (PRK) for myopia.

METHODS

Three hundred sixty-nine eyes of 257 patients were treated with an Aesculap-Meditec MEL 60 excimer laser. Treated eyes were divided into 3 groups: low myopes (-1.25 to -6.00 D), 226 eyes; medium myopes (-6.10 to -10.00 D), 104 eyes; high myopes (-10.10 to -25.00 D), 39 eyes. Follow-up at 12 months was available for 348 eyes (94%).

RESULTS

One year after surgery the number of eyes within +/- 1.00 D of emmetropia was 182 (86.7%) for low myopes, 43 (40.5%) for medium myopes, and 12 (30.8%) for high myopes. Values for +/- 0.50 D were low: 142 (67.6%), medium: 29 (29.3%), and high: 9 (23.1%). Three eyes with low myopia (1.4%) and 5 eyes with medium myopia (5.1%) lost 2 or more lines of spectacle-corrected visual acuity. None of the high myopes lost 2 or more lines. Uncorrected visual acuity of 20/20 or better was achieved in 82 eyes (39%) with low myopia; 20/40 or better was achieved in 183 eyes (87.1%). Five eyes (5.1%) of medium myopes achieved 20/20 or better; 52 eyes (52.5%) with medium myopia achieved 20/40 or better. Zero eyes with high myopia achieved 20/20 or better; 11 eyes (28.8%) achieved 20/40 or better.

CONCLUSION

Photorefractive keratectomy proved to be an effective method to correct myopia up to -6.00 D. For myopia greater than -6.00 D, good results were achieved in most eyes when myopia was less than -10.00 D, but efficacy and predictability decrease. To avoid systematic undercorrection, slight overcorrection must be attempted with the Aesculap-Meditec MEL 60 excimer laser for the treatment of myopia.

Effect of intracameral and intravitreal injection of calcitonin gene-related peptide on the intraocular pressure and outflow facility of aqueous humor in the rabbit

After intracameral injection calcitonin gene-related peptide has been demonstrated to break the blood aqueous barrier and increase intraocular pressure in rabbits. However in cats, calcitonin gene-related peptide decreases intraocular pressure by increasing the outflow facility of aqueous humor. In the present study, the effect of intracameral injection of calcitonin gene-related peptide on the outflow facility in rabbits has been investigated and the intraocular pressure and outflow facility were measured following intravitreal administration of calcitonin gene-related peptide. The results demonstrate that in spite of the apparent pseudofacility component caused by a breakdown of the blood aqueous barrier also the true trabecular outflow is probably increased in the rabbit eye after intracameral injection of calcitonin gene-related peptide. The intravitreal administration of calcitonin gene-related peptide leaves the blood aqueous barrier intact and causes an increase in the outflow facility of aqueous humor with a concomitant long-lasting decrease in intraocular pressure.

Production of cartilage collagens during metaphyseal bone healing in the mouse

Small defects of unfractured bone are believed to heal without a cartilaginous intermediate. We have determined the extent of cartilage production in an experimental model of metaphyseal bone repair involving defects in both cortical and cancellous bone, but no fracture. Northern analyses revealed the presence of mRNAs for type X and II collagens in the repair tissue. Immunohistology confirmed subperiosteal deposition of both collagen types adjacent to the defect. While the mRNAs for the two collagen types peaked by one week of defect healing, immunodetectable type X collagen was not observed until the second week. The data suggest that reactivity of periosteum and activation of chondrogenesis and subsequent endochondral ossification programs are involved in murine bone repair regardless of defect type.

Lectin binding in normal, scarred, and keratoconus corneas

PURPOSE

Keratoconus is characterized by central thinning and an increased curvature of cornea. Scarring of cornea accompanies the disease as it proceeds, and the ultimate treatment is keratoplasty. The pathogenesis of keratoconus is still unknown, and therefore we studied normal, keratoconus, and scarred corneas by a panel of lectin conjugates.

METHODS

The following lectin conjugates were used: concanavalin A (Con A), Dolichos biflorus agglutinin (DBA), peanut agglutinin (PNA), Ulex europaeus agglutinin (UEA-I), wheat-germ agglutinin (WGA), Helix aspersa agglutinin (HAA), Psophocarpus tetragonolobus agglutinin (PTA), soybean agglutinin (SBA), Griffonia simplicifolia agglutinin-I-B4 (GSA-I-B4), Ricinus communis agglutinin (RCA-I), and Lotus tetragonolobus agglutin (LTA) conjugates, differently recognizing saccharide residues in glycoconjugates.

RESULTS

One of the keratoconus corneas was badly scarred, whereas no scars were seen on histopathologic examination in other keratoconus corneas. In all keratoconus corneas, discontinuities or breaks (defects) were seen in the Bowman's layer. DBA and HAA conjugates, both blood group A reactive, reacted with corneal and conjunctival epithelium, blood vessels, and endothelium in blood groups A and AB. The blood group B-reactive GSA-I-B4 conjugate reacted with corneal and conjunctival epithelium, blood vessels, and endothelium only in specimens with blood group B. The blood group O-reactive UEA-I conjugate revealed the apical epithelial cells and blood vessels in all blood groups, whereas LTA conjugate, also blood group O reactive, reacted with all structures in cornea and conjunctiva despite blood groups. HAA and DBA conjugates reacted with defects in keratoconus corneas, SBA and RCA-I conjugates with defect area in keratoconus and scar region in scarred corneas, and PNA and WGA conjugates with the scar region of scarred keratoconus and scarred corneas. No other differences in the binding of lectins between normal, scarred, and keratoconus corneas were seen.

CONCLUSIONS

The results indicate that the blood group status influences lectin binding in cornea. Furthermore, the difference in lectin binding to defects in keratoconus corneas (HAA and DBA conjugates) and to scar regions in scarred corneas (PNA and WGA conjugates) suggests that the defects in keratoconus are not solely the results of scarring.

Excimer Laser Photorefractive Keratectomy for Hyperopia

OBJECTIVE

Excimer laser photorefractive keratectomy (PRK) has been shown to be an effective method in the treatment of refractive errors, especially myopia. We evaluated prospectively the efficacy, predictability, stability, and safety of excimer laser PRK in the treatment of hyperopia.

METHODS

Thirty-four hyperopic eyes were treated with an Aesculap-Meditec (MEL 60) excimer laser. The patients were divided into two groups. In the low-moderate hyperopia group, baseline spherical equivalent refraction was between +1.50 and +6.00 diopters (D) (mean, +4.20 +/- 1.30 D) and in the high hyperopia group between +6.25 and +9.75 D (mean, +7.70 +/- 1.30 D). Follow-up visits occurred 1, 3, 6, and 12 months after surgery.

RESULTS

One-year results were available for a total 27 eyes (79%): 15 eyes with low to moderate hyperopia and 12 eyes with high hyperopia. One year after PRK in the low-moderate group, six eyes (40%) had a refractive error within +/- 1.00 D of emmetropia, but in the high hyperopia group only two eyes (17%) were within +/- 1.00 D of emmetropia; three eyes (20%) and one eye (8%) were within +/- 0.50 D, respectively. The stability of the refractive change was better in the low to moderate hyperopia group; in the high hyperopia group there was still some regression after 6 months. At 12 months, 10 eyes (67%) in the low-moderate and one eye (8%) in the high hyperopia group had postoperative uncorrected visual acuity of 20/40 or better. One eye in the low-moderate hyperopia group saw 20/20 without correction. Only one eye lost two lines of spectacle-corrected visual acuity. Haze was more intense in the high hyperopia group, but it did not reduce visual acuity. No vision-threatening complications were observed.

CONCLUSIONS

When low to moderate hyperopia up to +6.00 D is treated, excimer laser PRK with the Aesculap Meditec MEL60 laser is safe and moderately effective, and refraction stabilizes after 3 months in most eyes. However, PRK is not sufficient to treat high hyperopia in an effective and predictable way.

The expression of tenascin and fibronectin in keratoconus, scarred and normal human cornea

BACKGROUND

The etiology and pathogenesis of keratoconus remain unclear, and therefore we decided to study the distribution of different isoforms of tenascin (Tn) and fibronectin (Fn) in normal human corneas and in those obtained from penetrating keratoplasty for keratoconus and corneal scarring.

METHODS

Frozen sections of human cornea and conjunctiva were stained by immunohistochemical methods with a panel of monoclonal antibodies (MAbs) against different isoforms of Tn and Fn.

RESULTS

In the normal human eye, Tn was found in the limbal and conjunctival basement membrane region, in the conjunctival blood vessels and at the junction of the cornea and sclera, but no immunoreaction was seen in the normal cornea. In the corneas from the keratoconus patients, a clear immunoreaction for Tn was seen in the defects of Bowman's membrane as well as in the distorted stroma beneath the defects. In some of the keratoconus corneas, basement membrane adjacent to the defects also showed reactivity for Tn, and in clinically and histologically scarred keratoconus corneas the scars expressed Tn. In the scarred corneas, only blood vessels in the posterior portion of the cornea showed immunoreactivity for Tn, while no Tn was noted in the scar area or in Bowman's membrane. No major differences were noticed in the reactivity of different MAbs against Tn isoforms. Fn, extradomain A Fn (EDA-Fn) and oncofetal Fn (onc-Fn) were found in the basement membrane of the central cornea of the normal eye. In keratoconus corneas, the defects and clinical and histological scars bound MAbs against Fn, EDA-Fn and onc-Fn, but in the scarred corneas no enhancement in the expression of Fns was noted. Extradomain B cellular Fn (EDB-Fn) was not expressed in any of the eyes studied.

CONCLUSIONS

The results suggest that the anterior portion of the cornea is involved in the pathogenesis of keratoconus. Furthermore, it seems that the expression of Tn and Fns in the clinically scarred keratoconus corneas is due to a process in which both repairing and scar-forming mechanisms operate at the same time. However, the origin of the defects in Bowman's membrane seen in keratoconus still remains unclear. They may be minor scars due to the disease or primary defects in the process leading to keratoconus.