Case of Progressive Keratoconus With Newly Diagnosed Pellucid Marginal Degeneration After Corneal Cross-Linking

PURPOSE

The purpose of this study was to document, to our knowledge, the first reported case of keratoconus progression accompanied with newly diagnosed pellucid marginal degeneration after corneal cross-linking (CXL).

METHODS

A novel case of further keratoconus progression plus development of pellucid marginal degeneration in the same eye after CXL was documented with supporting evidence from Scheimpflug and optical coherence tomography imaging.

RESULTS

A male patient was diagnosed with progressive keratoconus in the left eye and treated with CXL when aged 25 years. Although strongly cautioned not to rub his eyes, he admitted that he continued eye rubbing in association with atopic disease. At a follow-up examination 3.5 years after CXL, progressive keratoconus was detected and pellucid marginal degeneration was newly diagnosed in the left eye. The eye was retreated with CXL.

CONCLUSIONS

This case illustrates that progressive keratoconus and pellucid marginal degeneration can occur in the same eye after CXL and demonstrates the deleterious effects that can develop with continued eye rubbing.

Combined simultaneous photorefractive keratectomy and collagen cross-linking in keratoconus suspect patients

PURPOSE

To evaluate the safety and efficacy of combined simultaneous photorefractive keratectomy (PRK) with collagen cross-linking (CXL) in keratoconus suspects (KCS).

METHODS

This was a retrospective, non-randomized study of KCS patients who underwent combined simultaneous PRK with CXL. The efficacy, safety, refractive outcomes, and corneal wavefront aberration changes were assessed after the surgery and compared with existing preoperative data.

RESULTS

Fifty-six eyes of 28 patients, including 20 females (71.4%), with a mean age of 30.92±4.09 years, were enrolled. The mean follow-up was 19.46±8.48 months (range: 7-35). At the conclusion of the study, mean uncorrected distance visual acuity LogMAR improved from 0.89±0.44 preoperatively to 0.04±0.09 postoperatively (P<0.001). In addition, a statistically significant corneal flattening was observed postoperatively, with a decrease in manifest refraction. A statistically significant increase was found in higher-order aberrations (P<0.001), horizontal coma (P<0.001), and spherical aberration (P<0.001) compared with preoperatively. Postoperatively, 41% exhibited refractive astigmatism of 0.50 diopter (D) or less; 83.8% showed 1.00 D or less.

CONCLUSION

The results of our study indicate that combined simultaneous PRK with CXL can be a safe and effective method for treating refractive instability in KCS patients.

Diffuse Lamellar Keratitis in a Patient Undergoing Collagen Corneal Cross-Linking 18 Years After Laser In Situ Keratomileusis Surgery

PURPOSE

To report a case of diffuse lamellar keratitis (DLK) after corneal collagen cross-linking in an eye with a remote history of laser in situ keratomileusis (LASIK) surgery.

METHODS

This is a case report and literature review.

RESULTS

This report describes the development of unilateral stage IV DLK in a patient who underwent bilateral corneal cross-linking for corneal ectasia 18 years after LASIK surgery. The patient was treated with high-dose topical steroids that were tapered over 1 month and multiple flap lifts. The ultimate best-corrected visual outcome was 20/60.

CONCLUSIONS

DLK is a potential sight-threatening complication of refractive surgery that can occur at any time in the postoperative period, even years after the procedure. Undergoing a subsequent corneal procedure that may disrupt or promote inflammation within the surgical flap-stromal interface, such as corneal collagen cross-linking, is a recognized risk factor for the development of DLK. This case suggests that patients with any history of LASIK surgery undergoing corneal cross-linking or other lamellar corneal surgeries may benefit from closer follow-up (eg, daily) than patients with no history of LASIK.

Corneal cross-linking versus standard care in children with keratoconus - a randomised, multicentre, observer-masked trial of efficacy and safety (KERALINK): a statistical analysis plan

BACKGROUND

The KERALINK trial tests the hypothesis that corneal cross-linking (CXL) treatment reduces the progression of keratoconus in comparison to standard care in patients aged 10-16 years. This article describes the statistical analysis plan for this trial as an update to the published protocol. It is written before the end of the patient follow-up, while the outcome of the trial is still unknown.

DESIGN AND METHODS

KERALINK is a randomised controlled, observer-masked, multicentre trial in progressive keratoconus comparing epithelium-off CXL with standard care, including spectacles or contact lenses as necessary for best-corrected acuity. Keratoconus is a disorder of the shape of the cornea in which the normally round dome-shaped clear front window of the eye (cornea) thins progressively leading to a cone-like bulge. This impairs the ability of the eye to focus properly, causing reduced vision which requires spectacle or contact lens wear or, in a minority of patients, eventually corneal replacement by a transplant for best vision. The primary outcome measure is the between-group difference in K2 at 18 months adjusted for K2 at baseline examination. K2 is the value of the steepest corneal meridian as measured on Pentacam topography. Secondary outcomes are keratoconus progression, time to keratoconus progression, visual acuity, refraction, apical corneal thickness and adverse events. Patient-reported effects will be explored by questionnaires. We describe in detail the statistical aspects of KERALINK: the outcome measures, the sample size calculation, general analysis principles, the planned descriptive statistics and statistical models, and planned subgroup and sensitivity analyses.

DISCUSSION

The KERALINK statistical analysis will provide comprehensive and precise information on the relative effectiveness of the two treatments. The plan will be implemented in May 2020 when follow-up for the trial is completed.

TRIAL REGISTRATION

EudraCT, 2016-001460-11. Registered on 19 May 2016.

A randomised, controlled, observer-masked trial of corneal cross-linking for progressive keratoconus in children: the KERALINK protocol

INTRODUCTION

The KERALINK trial tests the hypothesis that corneal cross-linking (CXL) treatment reduces the progression of keratoconus in comparison to standard care in patients under 17 years old. KERALINK is a randomised controlled, observer-masked, multicentre trial in progressive keratoconus comparing epithelium-off CXL with standard care, including spectacles or contact lenses as necessary for best-corrected acuity.

METHODS AND ANALYSIS

A total of 30 participants will be randomised per group. Eligible participants aged 10-16 years with progressive keratoconus in one or both eyes will be recruited. Following randomisation, participants will be followed up 3-monthly for 18 months. The effect on progression will be determined by K₂ on corneal topography. The primary outcome measure is between-group difference in K₂ at 18 months adjusted for K₂ at baseline examination. Secondary outcomes are the effect of CXL on (1) keratoconus progression, (2) time to keratoconus progression, (3) visual acuity, (4) refraction, (5) apical corneal thickness and (6) adverse events. Patient-reported effects will be explored by questionnaires.

ETHICS AND DISSEMINATION

Research Ethics Committee Approval was obtained on 30 June 2016 (ref: 14/LO/1937). Current protocol: V.5.0 (08/11/2017). Study findings will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

European Union clinial trials register (EudraCT) 2016-001460-11.

Comparison of Polyethylene Wear before and after Hip Revision with Liner Exchange Fixed with the Original Locking Mechanism

Objective

To compare the wear of conventional ultra-high molecular weight polyethylene (CUHMWPE) and highly cross-linked polyethylene (HCLPE) in hip revision with liner exchange fixed with original locking mechanism using analysis of history medical data.

Methods

From Jan. 1, 2000, to Dec. 31, 2007, 26 patients (with 29 involved hips) underwent liner exchange revision fixed with the original locking mechanism due to wear of CUHMWPE and/or osteolysis. The mean age was 53 ± 9 years at the time of the primary total hip arthroplasty (THA) and 64 ± 9 years at the revision. The exchanged liners (Marathon, Depuy) were made of HCLPE. Annual X-rays were used to measure linear wear and osteolysis. The annual linear penetration was measured using PolyWare® software (Draftware Inc.). Annual Harris Hip Scores(HSS) were recorded.

Results

The mean follow-up time between the primary and revision THAs was 11 ± 2 years and 8 ± 2 years after revision. The mean Harris Hip Score(HHS) before primary THA, 1 year after primary THA, before revision and 1 year after revision was 43±5, 85±5, 71±6, 83±7 individually. The mean penetration of the CUHMWPE and HCLPE liners occurring in the first year were 0.44 ± 0.28 mm and 0.38 ± 0.14 mm, respectively (p = 0.211). The mean annual linear penetration of CUHMWPE and HCLPE from the second year onward were 0.29±0.09 mm and 0.08 ± 0.03 mm respectively (p <0.01). All THAs with CUHMWPE showed osteolysis on acetabular and/or femoral side before revision. No HCLPE liner showed osteolysis at the last follow-up. Conclusion: The CUHMWPE liner had a significantly higher wear rate than did the HCLPE liner. The HCLPE liner showed a satisfactory liner penetration rate after revision with isolated liner exchange fixed with the original locking mechanism.

A study comparing standard and transepithelial collagen cross-linking riboflavin solutions: epithelial findings and pain scores

PURPOSE

To evaluate epithelial signs and pain after epithelial-on corneal collagen cross-linking (Epi-on CCL) with new transepithelial riboflavin formulation and epithelial-off corneal collagen cross-linking (Epi-off CCL) with standard riboflavin formulation and to compare pain and duration of epithelial healing between both techniques.

METHODS

Thirty-nine eyes of 39 patients undergoing Epi-on CCL and 39 eyes of 39 patients undergoing Epi-off CCL were evaluated. Corneal epithelial signs and durations of corneal epithelial healing and subjective pain scores after the procedures were recorded and compared between 2 groups.

RESULTS

Total epithelialization was observed after 2.7 ± 0.7 days in Epi-on CCL and 2.3 ± 0.4 days in Epi-off CCL (P = 0.006). The mean pain score on the first day was 3.1 ± 0.6 in Epi-on CCL and 2.3 ± 0.4 in Epi-off CCL with a significant difference (P = 0.0001).

CONCLUSION

The epithelial damage was observed in both procedures; also, the epithelial healing time was longer in Epi-on CCL and it is of great importance that the patients should have therapeutic contact lenses until the epithelium heals in both procedures. The Epi-off CCL group had less pain scores than the Epi-on CCL group and more pain problems after Epi-on CCL still remains. The patient should be informed about pain, even if the Epi-on CCL procedure was performed.

The differences between ICL repair during and outside of S phase

DNA interstrand crosslinks (ICLs) are complex lesions that block essential DNA transactions including DNA replication, recombination, and RNA transcription. Naturally occurring ICLs are rare, yet these lesions are the major cause of toxicity following treatment with several classes of crosslinking cancer chemotherapeutic drugs. ICLs are repaired during and outside of S phase by pathways with overlapping as well as distinct features. Here, we discuss some recent insights into the mechanisms of replication-dependent and replication-independent repair of ICLs with special emphasis on the differences between these repair pathways.

Inactivation of matrix-bound matrix metalloproteinases by cross-linking agents in acid-etched dentin

OBJECTIVES

Published transmission electron microscopy analysis of in vitro resin-dentin bonds shows that, after 44 months, almost 70% of collagen fibrils from the hybrid layer disappear. Matrix metalloproteinases (MMPs) play an important role in that process and are thought to be the main factor responsible for the solubilization of dentin collagen. Therefore, this study aimed to evaluate the inactivation of matrix-bound MMPs by two different cross-linking agents, carbodiimide (EDC) or proanthocyanidin (PA), or the MMP-inhibitor, chlorhexidine (CHX), on acid-etched dentin using a simplified MMP assay method.

MATERIALS AND METHODS

Dentin beams (2×1×6 mm) were obtained from mid-coronal dentin of sound third molars and randomly divided into six groups (G) according to the dentin treatment: G1: Deionized water (control); G2: 0.1 M EDC; G3: 0.5 M EDC; G4: 0.5 M EDC + 35% hydroxyethyl methacrylate (HEMA); G5: 5% PA; and G6: 2% CHX. The beams were etched for 15 seconds with 37% phosphoric acid, rinsed, and then immersed for 60 seconds in one of the treatment solutions. The data were expressed both in absorbance values at 412 nm and in MMP-9 activity equivalents. The total MMP activity of dentin was analyzed for one hour by colorimetric assay (Sensolyte). Data were submitted to Wilcoxon nonparametric test and Mann-Whitney tests (p>0.05).

RESULTS

All experimental cross-linking solutions significantly reduced MMP activity from 79.8% to 95.2% when compared to the control group. No difference was observed among 0.1 M EDC (84.8%), 5% PA (87.6%), and 2% CHX (79.8%). Addition of 35% HEMA to 0.5 M EDC produced inactivation (95.2%) that was similar to that of 0.5 M EDC alone (92.7%).

CONCLUSION

Dentin treatment with cross-linking agents is effective to significantly reduce MMP activity. Mixing 0.5 M EDC and 35% HEMA did not influence EDC inhibitor potential.

Exploratory, randomized, controlled, phase 2 study to evaluate the safety and efficacy of adjuvant fibrin sealant VH S/D 4 S-Apr (ARTISS) in patients undergoing rhytidectomy

BACKGROUND

Suction drains are commonly placed after rhytidectomy surgery to avoid seroma formation that may result from dead spaces between skin layers. Fibrin sealants promote tissue adherence by cross-linking with extracellular matrix proteins, which may reduce the dead space under skin flaps.

OBJECTIVES

The authors evaluate the safety and preliminary efficacy of the fibrin sealant (FS) VH S/D 4 s-apr (ARTISS; Baxter Healthcare Corp, Deerfield, Illinois), added to standard-of-care (SoC) treatment, on tissue plane adherence and local hemostasis in rhytidectomy patients.

METHODS

In this phase 2, prospective, controlled, randomized, evaluator- and patient-blinded, multicenter study, 45 patients (of 56 possible enrollees) received SoC treatment on 1 side of the face and adjunctive FS VH S/D 4 s-apr treatment on the other side. Outcomes measures included visual assessments of ecchymosis (by blinded reviewers), grading of ecchymosis and edema, drainage volumes, occurrence of hematoma/seroma, safety evaluations, and patient-reported assessments of pain, numbness, and treatment preferences postoperatively.

RESULTS

Mean patient age was 55.1 years. Rates and grades of ecchymosis and edema were similar for the 2 treatments. The mean (SD) drainage volume 24 hours after surgery was 11.5 (13.7) mL from the FS VH S/D 4 s-apr-treated sides of the face and 26.8 (24.0) mL from the SoC-only sides (P < .0001). Patient assessments of pain, numbness, and preference favored treatment with FS VH S/D 4 s-apr. Adverse events were mild to moderate in severity.

CONCLUSIONS

Adjuvant use of FS VH S/D 4 s-apr appears to be safe and results in lower drainage volumes than SoC treatment alone.

Biocompatibility of genipin and glutaraldehyde cross-linked chitosan materials in the anterior chamber of the eye

Chitosan is a naturally occurring cationic polysaccharide and has attracted much attention in the past decade as an important ophthalmic biomaterial. We recently demonstrated that the genipin (GP) cross-linked chitosan is compatible with human retinal pigment epithelial cells. The present work aims to further investigate the in vivo biocompatibility of GP-treated chitosan (GP-chi group) by adopting the anterior chamber of a rabbit eye model. The glutaraldehyde (GTA) cross-linked samples (GTA-chi group) were used for comparison. The 7-mm-diameter membrane implants made from either non-cross-linked chitosan or chemically modified materials with a cross-linking degree of around 80% were inserted in the ocular anterior chamber for 24 weeks and characterized by slit-lamp and specular microscopic examinations, intraocular pressure measurements, and corneal thickness measurements. The interleukin-6 expressions at mRNA level were also detected by quantitative real-time reverse transcription polymerase chain reaction. Results of clinical observations showed that the overall ocular scores in the GTA-chi groups were relatively high. In contrast, the rabbits bearing GP-chi implants in the anterior chamber of the eye exhibited no signs of ocular inflammation. As compared to the non-cross-linked counterparts, the GP-chi samples improved the preservation of corneal endothelial cell density and possessed better anti-inflammatory activities, indicating the benefit action of the GP cross-linker. In summary, the intracameral tissue response to the chemically modified chitosan materials strongly depends on the selection of cross-linking agents.

Contributions of DNA interstrand cross-links to aging of cells and organisms

Impaired DNA damage repair, especially deficient transcription-coupled nucleotide excision repair, leads to segmental progeroid syndromes in human patients as well as in rodent models. Furthermore, DNA double-strand break signalling has been pinpointed as a key inducer of cellular senescence. Several recent findings suggest that another DNA repair pathway, interstrand cross-link (ICL) repair, might also contribute to cell and organism aging. Therefore, we summarize and discuss here that (i) systemic administration of anti-cancer chemotherapeutics, in many cases DNA cross-linking drugs, induces premature progeroid frailty in long-term survivors; (ii) that ICL-inducing 8-methoxy-psoralen/UVA phototherapy leads to signs of premature skin aging as prominent long-term side effect and (iii) that mutated factors involved in ICL repair like ERCC1/XPF, the Fanconi anaemia proteins, WRN and SNEV lead to reduced replicative life span in vitro and segmental progeroid syndromes in vivo. However, since ICL-inducing drugs cause damage different from ICL and since all currently known ICL repair factors work in more than one pathway, further work will be needed to dissect the actual contribution of ICL damage to aging.

Bioreversibly crosslinked polyplexes of PEI and high molecular weight PEG show extended circulation times in vivo

Copolymers consisting of branched PEI 25 kDa grafted with high molecular weight PEG at a low degree of substitution were successfully synthesized using a simple two-step procedure. The resulting AB-type and ABA-type copolymers were tested for cytotoxicity and DNA condensation and complexation properties. Their polyplexes with plasmid DNA were characterized in terms of DNA size and surface charge, transfection efficiency and blood compatibility. Pharmacokinetic profiles of the complexes containing (32)P-labeled plasmid were assessed before and after surface crosslinking. A set of four copolymers containing one or two PEG 20 kDa or PEG 30 kDa chains was obtained. The cytotoxicity of PEI was strongly reduced after copolymerization. The copolymer polyplexes showed hydrodynamic diameters of less than 200 nm, comparable to PEI 25. Similarly, no reduction in DNA condensation and complexation properties was found. In fact, PEI-PEG(30 k) copolymers exhibited better condensation and complexation properties than PEI 25. The transfection efficiency of copolymer polyplexes was increased 10-fold compared to PEI 25 control and the hemolytic activity was markedly reduced. After intravenous injection into mice, plasmids complexed to PEI-PEG(30 k) copolymers resulted in significantly increased circulation times. After stabilizing the polyplexes with a redox sensitive, biodegradable crosslinker, blood levels of plasmid could be further increased up to 125% compared to PEI. These results demonstrate that polyplexes prepared using a combined strategy of surface crosslinking and PEGylation seem to provide promising properties as stable, long circulating vectors.

Carboxypeptidase-G2-based gene-directed enzyme-prodrug therapy: a new weapon in the GDEPT armoury

Gene-directed enzyme-prodrug therapy (GDEPT) aims to improve the therapeutic ratio (benefit versus toxic side-effects) of cancer chemotherapy. A gene encoding a 'suicide' enzyme is introduced into the tumour to convert a subsequently administered non-toxic prodrug into an active drug selectively in the tumour, but not in normal tissues. Significant effects can now be achieved in vitro and in targeted experimental models, and GDEPT therapies are entering the clinic. Our group has developed a GDEPT system that uses the bacterial enzyme carboxypeptidase G2 to convert nitrogen mustard prodrugs into potent DNA crosslinking agents, and a clinical trial of this system is pending.

L'anémie de Fanconi : aspects cellulaires et moléculaires

Fanconi anemia (FA) is a recessive human cancer prone syndrome featuring bone marrow failure, developmental abnormalities and hypersensitivity to DNA crosslinking agents exposure. 11 among 12 FA gene have been isolated. The biochemical functions of the FANC proteins remain poorly understood. Anyhow, to cope with DNA crosslinks a cell needs a functional FANC pathway. Moreover, the FANC proteins appear to be involved in cell protection against oxidative damage and in the control of TNF-alpha activity. In this review, we describe the current understanding of the FANC pathway and we present how it may be integrated in the complex networks of proteins involved in maintaining the cellular homeostasis.

A multi-step approach in anti-calcification of glutaraldehyde-preserved bovine pericardium

AIM

Bioprosthetic cardiovascular substitutes, manufactured from glutaraldehyde-preserved bovine or porcine tissues, are prone to calcification after implantation. The aim of the study was to evaluate the ultrastructure, material stability and calcification behaviour of glutaraldehyde-preserved bovine pericardium, treated with a multi-step anti-calcification process which addresses each of the major causes of calcification and tissue degeneration.

METHODS

Bovine pericardium samples were divided into 2 groups. Group I (control) consisted of tissue fixed with 0.625% glutaraldehyde and Group II (study group) consisted of tissue fixed with 0.625% glutaraldehyde and exposed to a multi-step anti-calcification process. Ultrastructure was examined by scanning electron microscopy and material stability was assessed by mechanical testing, shrinkage temperature and enzymatic degradation. Calcification was assessed by histology (Von Kossa stain) and by atomic absorption spectrophotometry in the subcutaneous rat model.

RESULTS

Bovine pericardium in the study group revealed less visible changes in the ultrastructure of the collagen matrix, improved material stability (P<0.05) and significantly (P<0.001) reduced calcification compared to control tissues (4.5+/-1.2 versus 136.03+/-11.39 ug/mg tissue).

CONCLUSIONS

In conclusion, results demonstrate that the multi-step anticalcification process improved the material stability and reduced the calcification potential of bovine pericardial tissue. These improvements in the quality of the bovine pericardium should enhance the long-term durability of the tissue as a bioprosthetic substitute for cardiovascular application.

Composition of hyaluronan affects wound healing in the rabbit maxillary sinus

BACKGROUND

Hyaluronan (HA) is a ubiquitous component of the extracellular matrix. HA and its derivatives have been used in the sinuses to reduce scarring and possibly promote wound healing. However, in recent animal studies, HA esters exhibited inflammatory effects. Mitomycin C (MMC) is another potential antiscarring treatment. This study prospectively evaluated the effects of three different HA constructs on wound healing in the rabbit maxillary sinus: (i) a novel cross-linked HA hydrogel, (ii) the cross-linked HA gel containing covalently bound MMC, and (iii) a commercially available woven HA ester (Merogel).

METHODS

Ostia were created with a 4-mm otologic drill in the maxillary sinuses of 15 New Zealand white rabbits with one side randomly chosen for treatment. After 14 or 21 days the size of the maxillary ostia were recorded and the tissue was examined under light microscopy.

RESULTS

Sinuses treated with the novel HA and HA-MMC hydrogels showed an increased ostial diameter compared with untreated controls. Woven HA ester-treated sinuses showed no improvement, with a trend toward a smaller ostium than controls. Histological examination showed that woven HA ester tended to cause increased fibrosis and granulomatous inflammation, and heterophilia was slightly increased in the HA hydrogel-treated sinuses. Blinded observation noted foamy macrophages surrounding the residual woven HA ester in each specimen while no similar reaction was noted near the residual HA or HA-MMC hydrogels.

CONCLUSION

This study suggests that the degree of ostial narrowing, inflammation, and fibrosis depends on the formulation of the HA used. Minimal, if any, additional benefit is seen with addition of MMC to the HA hydrogel in this pilot study.

Transglutaminases: a meeting point for wheat allergy, celiac disease, and food safety

Wheat is the staple cereal in many countries and its uses in manufactured foods are ever growing due to the technological qualities of gluten proteins. Transglutaminases (TG) are ubiquitous enzymes with many functions. They are able to transform proteins by deamidation and/or transamidation. This last reaction can cross-link proteins together. Intestinal tissue TG has been shown to play an important role in two kinds of immune reactions to wheat: celiac disease and wheat-dependent exercise-induced anaphylaxis. In addition, new epitopes have been suspected in cases of anaphylaxis to wheat isolates, a food ingredient consisting mainly of deamidated gluten proteins. As a microbial TG is included in many food technological processes, its safe use should be checked. This assessment must cover not only the safety of the TG itself but also that of the deamidated/cross-linked proteins generated by this enzyme. This article aims at discussing the possible consequences of using TG in food industry in the light of today knowledge about immune reactions to wheat.

Immunotherapy with depigmented glutaraldehyde-polymerized extracts: changes in quality of life

BACKGROUND

Immunotherapy (IT) with modified allergens reduces allergic rhinitis (AR) symptoms and medications requirements. Improvement of quality of life (QOL) is a key point in the treatment of AR. The aim of this study was to provide evidence of changes related to the patient's QOL (well-being) induced by a modified (depigmented glutaraldehyde-polymerized) therapeutic vaccine and of its safety.

MATERIAL AND METHODS

Fifty-three patients with a well-documented clinical history of seasonal AR sensitized to Dactylis glomerata and Olea europaea pollens were included in a randomized clinical trial. Twenty-five patients (Group-A) received a mixture of D. glomerata and O. europaea pollen extracts and 28 patients received placebo (group-C). Any adverse event was recorded and graded in accordance with EAACI guidelines. RQLQ was recorded before the treatment (pollen season 2000) and after 1 year of treatment (pollen season 2001). Dose-response skin prick test with each allergen extract was conducted at baseline and at the end of the study.

RESULTS

Each patient received 17 injections during this period. All patients completed the trial and no systemic adverse reactions were recorded. Symptom scores (P<0.001) and medication requirements (P<0.001) were significantly reduced in the IT group during the pollen season. This patient group also experienced greater and statistically significant improvement in overall RQLQ score and in five of the seven domains, all of them surpassing the threshold of 'minimal important difference' of 0.5 points.

CONCLUSIONS

Results of this study provided evidence that IT with depigmented, glutaraldehyde-modified allergen extracts was well-tolerated and added beneficial effects to AR treatment in pollen allergic patients eliciting an improvement in QOL enough to justify a change in the patient's treatment.

Self-cross-linking biopolymers as injectable in situ forming biodegradable scaffolds

The injectable polymer scaffolds which are biocompatible and biodegradable are important biomaterials for tissue engineering and drug delivery. Hydrogels derived from natural proteins and polysaccharides are ideal scaffolds for tissue engineering since they resemble the extracellular matrices of the tissue comprised of various amino acids and sugar-based macromolecules. Here, we report a new class of hydrogels derived from oxidized alginate and gelatin. We show that periodate-oxidized sodium alginate having appropriate molecular weight and degree of oxidation rapidly cross-links proteins such as gelatin in the presence of small concentrations of sodium tetraborate (borax) to give injectable systems for tissue engineering, drug delivery and other medical applications. The rapid gelation in the presence of borax is attributed to the slightly alkaline pH of the medium as well as the ability of borax to complex with hydroxyl groups of polysaccharides. The effect of degree of oxidation and concentration of alginate dialdehyde, gelatin and borax on the speed of gelation was examined. As a general rule, the gelling time decreased with increase in concentration of oxidized alginate, gelatin and borax and increase in the degree of oxidation of alginate. Cross-linking parameters of the gel matrix were studied by swelling measurements and trinitrobenzene sulphonic acid (TNBS) assay. In general, the degree of cross-linking was found to increase with increase in the degree of oxidation of alginate, whereas the swelling ratio and the degree of swelling decreased. The gel was found to be biocompatible and biodegradable. The potential of the system as an injectable drug delivery vehicle and as a tissue-engineering scaffold is demonstrated by using primaquine as a model drug and by encapsulation of hepatocytes inside the gel matrix, respectively.

Functional evaluation and cancer risk assessment of BRCA2 unclassified variants

The influence of germ line BRCA2 unclassified variants (UCV), including missense mutations and in-frame deletions and insertions on BRCA2 function and on cancer risk, has not been defined although these mutations account for 43% of all identified BRCA2 sequence alterations. To investigate the effects of UCVs on BRCA2 function, we compared mutant and wild-type forms of BRCA2 using assays of cellular survival and viability, homologous recombination repair, and genome instability. We confirm that the effects of known deleterious mutations can be distinguished from neutral polymorphisms and wild-type BRCA2 in these assays, and we characterize the influence of a series of UCVs on BRCA2 function. We also describe how the results from the assays can be combined with data from analysis of cosegregation of the UCVs with cancer, co-occurrence of the UCVs with other deleterious mutations, and interspecies sequence variation in a comprehensive framework in an effort to better distinguish between disease predisposing and neutral UCVs. This combined approach represents a useful means of addressing the functional significance and cancer relevance of UCVs in BRCA2.

Elevated levels of DNA-protein crosslinks and micronuclei in peripheral lymphocytes of tannery workers exposed to trivalent chromium

DNA-protein crosslinks (DPC) are a promising biomarker of exposure to hexavalent chromium, a known human carcinogen. Although trivalent chromium is considered to have much lower toxicity, the risk involved in chronic exposure is uncertain. DPC may be a useful tool in clarifying this risk, by signaling an exposure of body tissues to biologically active forms of chromium. DPC quantification was carried out in lymphocytes of a group of tannery workers exposed to trivalent chromium, a small group of manual metal arc stainless steel welders exposed to hexavalent chromium and a control group. This biomarker was compared with the frequency of micronuclei in cytokinesis blocked peripheral lymphocytes as a biomarker of cytogenetic lesions and total plasma and urine chromium levels as an index of exposure. The results indicate a significant increase in the formation of DPC in tannery workers compared with controls (0.88 +/- 0.19 versus 0.57 +/- 0.21%, P < 0.001, Mann-Whitney test) and an even higher level of DPC in welders (2.22 +/- 1.12%, P = 0.03). Tanners showed a significant increase in micronucleated cells compared with controls (6.35 +/- 2.94 versus 3.58 +/- 1.69 per thousand, P < 0.01), whereas in welders this increase was not significant (5.40 +/- 1.67 per thousand ). Urinary chromium was increased in both groups, with a greater increase observed in tanners compared with controls (2.63 +/- 1.62 versus 0.70 +/- 0.38 microg/g creatinine, P < 0.001) than in welders (1.90 +/- 0.37 microg/g creatinine, P < 0.005). Plasma chromium was also increased in both groups (tanners 2.43 +/- 2.11 microg/l, P < 0.001, welders 1.55 +/- 0.67 microg/l, P < 0.005 versus controls 0.41 +/- 0.11 microg/l). In summary, chronic occupational exposure to trivalent chromium can lead to a detectable increase in lymphocyte DNA damage which correlates with a significant exposure of the cells to the metal.

Alternative fixation of bioprostheses

The glutaraldehyde fixation technique for bioprosthetic tissue valves has been used for about 30 years. It is more or less generally recognized, however, that a solution to the ongoing problems of calcification and immunomodulated inflammation can only be achieved with the development of alternative fixation techniques that differ from fixation with glutaraldehyde. This review reports on the chemistry behind newly developed tissue-fixation processes and the preliminary results achieved with these.

Intravenous safety and pharmacokinetics of a novel dimerizer drug, AP1903, in healthy volunteers

AP1903 is a novel gene-targeted drug that is being developed for use in drug-regulated cell therapies. An intravenous, single-blind, placebo- and saline-controlled, ascending-dose study was performed to evaluate the safety, tolerability, and pharmacokinetics of AP1903. Twenty-eight normal healthy male volunteers were randomized into five dosage groups of AP1903 (0.01, 0.05, 0.1, 0.5, and 1 mg/kg). Within each group, 4 volunteers received a single dose of AP1903, 1 volunteer received an equal volume of placebo, and 1 received an equal volume of normal saline. The only exception was in the 0.5 mg/kg group, in which 4 volunteers were dosed: 3 received AP1903 and 1 received normal saline. All dosages were administered as intravenous infusions over 2 hours. Clinical safety parameters were monitored, and serial blood and urine samples were collected for analysis of AP1903. No drug-related adverse events were observed at any of the dose levels with the possible exception of facial flushing in 1 volunteer at the 1.0 mg/kg dose level. AP1903 plasma levels were directly proportional to the administered dose, with mean Cmax values ranging from approximately 10 to 1,275 ng/mL over the 0.01 to 1.0 mg/kg dose range. Following the infusion period, blood concentrations revealed a rapid distribution phase, with plasma levels being reduced to approximately 18%, 7%, and 1% of the maximal concentration at 0.5, 2, and 10 hours postdose, respectively. AP1903 was shown to be safe and well tolerated at all dose levels and demonstrated a favorable pharmacokinetic profile at doses well above the anticipated therapeutic dose.

4-hydroxynonenal induces apoptosis via caspase-3 activation and cytochrome c release

We investigated the mechanism by which 4-hydroxynonenal (HNE), a major aldehydic product of lipid peroxidation, induces apoptosis in tumor cells. Treatment of human colorectal carcinoma (RKO) cells with HNE-induced poly-ADP-ribose-polymerase (PARP) cleavage and DNA fragmentation in a dose- and time-dependent manner. The induction of PARP cleavage and DNA fragmentation paralleled caspase-2, -3, -8, and -9 activation. Pretreatment of cells with an inhibitor of caspase-3, z-DEVD-fmk, or a broad spectrum caspase inhibitor, z-VAD-fmk, abolished caspase activation and subsequent PARP cleavage. Constitutive expression of high levels of Bcl-2 protected cells from HNE-mediated apoptosis. In addition, Bcl-2 overexpression inhibited cytochrome c release from mitochondria and subsequent caspase-2, -3, and -9 activation. These findings demonstrate that HNE triggers apoptotic cell death through a mitochondrion-dependent pathway involving cytochrome c release and caspase activation. Bcl-2 overexpression protected cells from HNE-induced apoptosis through inhibition of cytochrome c release.

Antitumoral activity of a sulphur-containing platinum complex with an acidic pH optimum

Platinum complexes are essential tools for cancer treatment despite their toxic side effects. Here we describe a new platinum complex with sulphurs as complexing atoms (thioplatin).

PURPOSE

To demonstrate that the antitumoral activity of a new sulphur-containing platinum compound (thioplatin) depends on a slightly acidic pH.

METHODS

Platinum uptake by tumour cells and interaction with DNA was determined at slightly acidic or alkaline pH. To demonstrate low in vivo toxicity the effects of thioplatin on body weight, blood urea nitrogen, white blood cell count and the histopathological appearance of small intestines and kidneys were evaluated at doses that displayed antitumoral effects against human small-cell lung cancer and human colorectal cancer xenotransplants in nude mice.

RESULTS

The slightly acidic pH optimum of thioplatin was proven by the altered electrophoretic mobility of plasmid DNA, quantitation of the platinum content in the DNA of tumour cells and cytotoxicity studies. Thioplatin displayed antitumoral activity without severe side effects such as weight loss, renal ischaemia, destruction of villi in the small intestine or leukopenia as observed at comparable doses of cisplatin. Furthermore, probably due to its lipophilic nature, thioplatin was taken up readily even by cisplatin-resistant cells. In vivo studies with human tumour xenografts in nude mice showed a therapeutic index of thioplatin five to ten times higher than that of cisplatin.

Protein oxidation in aging and age-related diseases

Although different theories have been proposed to explain the aging process, it is generally agreed that there is a correlation between aging and the accumulation of oxidatively damaged proteins, lipids, and nucleic acids. Oxidatively modified proteins have been shown to increase as a function of age. Studies reveal an age-related increase in the level of protein carbonyl content, oxidized methionine, protein hydrophobicity, and cross-linked and glycated proteins as well as the accumulation of less active enzymes that are more susceptible to heat inactivation and proteolytic degredation. Factors that decelerate protein oxidation also increase the life span of animals and vice versa. Furthermore, a number of age-related diseases have been shown to be associated with elevated levels of oxidatively modified proteins. The chemistry of reactive oxygen species-mediated protein modification will be discussed. The accumulation of oxidatively modified proteins may reflect deficiencies in one or more parameters of a complex function that maintains a delicate balance between the presence of a multiplicity of prooxidants, antioxidants, and repair, replacement, or elimination of biologically damaged proteins.

Identification of human lung and skin proteins conjugated with hexamethylene diisocyanate in vitro and in vivo

Diisocyanates are asthma-causing chemicals used in the commercial production of polyurethane. We have previously shown that human lung epithelial cell proteins can become conjugated with hexamethylene diisocyanate (HDI) and may be biologically important in diisocyanate-induced asthma. The objective of this study was to identify specific human lung and skin proteins that become conjugated with diisocyanate after in vitro and in vivo exposure. Following in vitro exposure of human airway epithelial cells (A549), keratin 18, the 78-kD glucose-regulated protein, trans-1, 2-dihyrobenzene-1,2-diol dehydrogenase, and actin were identified as prominent diisocyanate-conjugated proteins through use of a combination of immunocytochemical and mass spectrometric techniques. Following in vivo inhalation of an HDI aerosol, keratin 18 was also identified as the predominant diisocyanate-conjugated protein in human endobronchial biopsy samples, whereas albumin was the predominant diisocyanate-conjugated protein in bronchoalveolar lavage fluid. Keratin was also identified as a predominant diisocyanate-conjugated protein in human skin biopsy samples after epicutaneous exposure to liquid-phase HDI, although the major skin diisocyanate-conjugated protein (56-kD) differed from the predominant lung diisocyanate-conjugated keratin (47-kD). The data from this study identify keratin and other proteins as potential "carriers" for diisocyanates in vivo, and suggest that HDI conjugation of these proteins may play a role in the pathogenesis of diisocyanate-induced asthma.

Contact allergy and hand eczema in Swedish dentists

Hand eczema and contact allergy in Swedish dentists were studied in a multidisciplinary project. The aims of the study were to establish diagnoses, to investigate the occurrence of contact allergy, in particular to (meth)acrylates, and to evaluate certain consequences of hand eczema. A postal questionnaire on skin symptoms, atopy and occupational experience was mailed to 3,500 dentists aged <65 years, and licensed 1965-1995. The response rate was 88%. Among dentists living in 3 major cities, 14.9% (n= 191) reported hand eczema during the previous year. They were invited to a clinical examination, including patch testing with a standard and a dental series. 158/191 (83%) dentists attended, and hand eczema diagnosis was confirmed in 149/158 (94%). Irritant contact dermatitis was diagnosed in 67% and allergic contact dermatitis in 28%. On patch testing, 50% presented at least 1 positive reaction. The most frequent allergens were nickel sulfate, fragrance mix, gold sodium thiosulfate and thiuram mix. 7 (5%) had positive reactions to (meth)acrylates, all to 2-hydroxyethyl methacrylate and 6 also to ethyleneglycol dimethacrylate. 38% had consulted a physician, 4% had been on sick-leave and 1% had changed occupational tasks due to hand eczema. No dentist with allergy to acrylates had been on sick-leave or changed occupation. It is concluded that dentistry is a high-risk occupation for hand eczema, and that irritant contact dermatitis is most common. The prevalence of contact allergy to acrylates was below 1% in the population of responding dentists, and in most cases did not have serious medical, social or occupational consequences.

Phase II study of bendamustine in patients with relapsed or cisplatin-refractory germ cell cancer

Despite generally high cure rates in patients with metastatic germ cell cancer, patients with incomplete response to first-line cisplatin-based chemotherapy or with relapsed disease following high-dose salvage therapy exhibit a very poor prognosis. We investigated the efficacy and toxicity of bendamustine, a bifunctional alkylating benzimidol derivative with only partial cross-resistance to other alkylating agents such as ifosfamide or cyclophosphamide. Nineteen patients with cisplatin-refractory germ cell tumors (GCT) or relapse after high-dose chemotherapy plus autologous stem cell support were treated with bendamustine at a dose of 120 mg/m2 on 2 consecutive days at 3 week intervals. Patients had received a median of 9 (range 4-20) platinum-containing treatment cycles prior to bendamustine and 13 patients (68%) had previously received carboplatin/etoposide-based high-dose chemotherapy. One patient achieved a partial remission of only 6 weeks duration. No other responses were seen. Toxicity was low with one patient developing WHO grade 3 thrombocytopenia as the only WHO grade 3/4 toxicity observed. Hematologic toxicity was similar in patients pretreated with and without high-dose chemotherapy plus autologous stem cell support. We conclude that bendamustine has little or no clinically relevant activity in patients with cisplatin-refractory GCT or relapsed disease after high-dose chemotherapy.

Too hot to handle: an unusual exposure of HDI in specialty painters

BACKGROUND

Hexamethylene Diisocyanate (HDI) is a color stable aliphatic isocyanate that is used in specialty paints as a hardener. Due to the lower vapor pressure of its commercial biuret form, it is considered a relatively "safe" isocyanate from an exposure standpoint. This case series reports on an unusual toxic exposure to HDI. Between November 1993 and May 1994, seven specialty painters and one boiler maker who were working at three different power plants were examined at the Institute of Occupational and Environmental Health at West Virginia University. At their respective work sites, HDI was applied to the hot surfaces of boilers that were not shut down, and allowed sufficient time to cool. Consequently, these workers were exposed to volatile HDI and its thermal decomposition products.

METHODS

All of these workers underwent a complete physical examination, spirometry, and methacholine challenge testing.

RESULTS

All 8 workers complained of dyspnea, while 4 of the 8 also complained of rash. On examination 3 workers were methacholine challenge positive and 2 had persistent rash. At follow-up 4 years later, 5 workers still had to use inhalation medication and one had progressive asthma and dermatitis. All 8 workers, by the time of the follow-up, had gone through economic and occupational changes.

CONCLUSIONS

This case series reports on an unusual exposure to HDI. It is unusual in that: 1) There were two simultaneous sentinel cases with two different Material Safety Data Sheets (MSDS) for the same product, 2) Exposure was to volatile HDI and its decomposition products and 3) Hazardous conditions of exposure occurred at three different sites.

Current diagnostic methods for diisocyanate induced occupational asthma

BACKGROUND

Diisocyanates are among the most frequent causes of occupational asthma in industrialized countries. Early diagnosis of diisocyanate asthma followed by prompt termination of chemical exposure can prevent chronic morbidity due to persistent asthma. The accurate diagnosis of diisocyanate asthma requires a systematic approach that combines information obtained from the occupational history, immunologic tests and physiologic studies.

METHODS

The advantages, limitations and validity of various methods and diagnostic guidelines utilized in the evaluation of diisocyanate asthma are reviewed.

RESULTS

Recommended methods for evaluation of diisocyanates asthma are similar to approaches for other causative agents. Serologic assays of specific IgE are specific but insensitive diagnostic markers of diisocyanate asthma. If possible, workers should be evaluated, while at work, in order to demonstrate work-related changes in lung function associated with diisocyanate exposures. Specific bronchoprovocation challenge testing with diisocyanates, is reserved for situations where the diagnosis cannot be confirmed at work. Such tests can be performed safely but should be conducted exclusively at specialized centers by experienced personnel.

CONCLUSIONS

Published diagnostic guidelines for occupational asthma are directly applicable to the evaluation of diisocyanate asthma.

[Bullous phototoxic contact dermatitis caused by Ruta graveolens L. (garden rue), Rutaceae. Case report and review of literature]

A patient developed severe bullous phototoxic contact dermatitis caused by Ruta graveolens L. (garden rue) which belongs to the Rutaceae family. To date only a few cases of phototoxic reactions to the garden rue have been reported. The phototoxic components of Ruta graveolens L. are the fouranocoumarins 5-methoxypsoralen (bergapten) and 8-methoxypsoralen (xanthotoxine), and the furanoquinoline dictamnine whose phototoxic properties were recently discovered. Since the garden rue is frequently cultivated, it should be considered in the differential diagnosis of phototoxic phytodermatitis.

Serotonin-independent model of cisplatin-induced emesis in the ferret

para-Chlorophenylalanine (PCPA, 100-200 mg/kg) was used as a pharmacological tool to characterize the 5-hydroxytryptamine (5-HT) involvement in the emesis occurring 24 hr after the administration of cisplatin (10 mg/kg) in the ferret. PCPA was effective to antagonize the initial 8 hr period of retching and vomiting, but potentiated the emesis that occurred during the remaining 8- to 24-hr observation period. Tissue samples removed from the brainstem at 24 hr post injection of cisplatin alone revealed an elevation of 5-HT, dopamine and homovanillic acid that was antagonized by the injection of PCPA. Cisplatin also induced increases in the urinary levels of 5-hydroxyindoleacetic acid that was similarly antagonized by PCPA. Results are discussed in terms of the relevance of 5-HT to the model of cisplatin (10 mg/kg)-induced emesis in the ferret compared to the problem of acute and delayed emesis in man. The residual or delayed phase of cisplatin-induced emesis may involve a 5-HT-independent mechanism.

Complications of periurethral collagen injection for stress urinary incontinence

PURPOSE

Periurethral collagen injection has been advocated as a safe and effective method of treatment for stress urinary incontinence. This study was conducted to determine the complications associated with transurethral collagen injection for treatment of stress urinary incontinence in women. We report the incidence and management of adverse effects.

MATERIALS AND METHODS

A total of 337 women with at least a 1-year history, physical findings and urodynamic abnormalities consistent with stress urinary incontinence, who required pads or protective clothing, and who had no or only grade 1 cystocele were enrolled in this prospective cohort study. A third party documented adverse effects at each followup.

RESULTS

De novo urinary urgency with incontinence was the most frequent and serious complication, occurring in 12.6% of patients, and in many the symptoms were irreversible. Hematuria (5% of patients) and urinary retention (1.9%) were short-lived and resolved spontaneously. Delayed reaction at the skin test site occurred in 0.9% of the patients (3) and was associated with arthralgias in 2.

CONCLUSIONS

Contrary to previous reports that periurethral collagen injection is complication-free, we found an overall incidence of 20% risk of complications in any given individual.

Urethral prolapse after collagen injection

A woman who was treated for intrinsic urethral sphincteric deficiency with periurethral injection of glutaraldehyde cross-linked collagen had prolapse of the urethral mucosa and recurrence of incontinence. She subsequently required surgical resection and a fascia lata sling. This is the first known occurrence of this postinjection complication.

Misdiagnosis of cancer due to multiple glove powder granulomas

A biologically absorbable powder, the cornstarch lubricant used in the production of gloves, is treated with epichlorohydrin, a cross-linking agent forming one to three diether glycerine groups to create a glove lubricating powder. This agent, together with chemicals used in glove fabrication is able to interfere with important biological diagnostic procedures, such as polymerase chain reaction (PCR) and enzyme immunoassay as well as to induce a granulomatous reaction in traumatised surgical tissue.

Thermal cross-linking for biologically degradable materials. Preliminary report

To diminish undesirable side effects of chemical cross-linking of biodegradable materials, the authors developed a thermal cross-linking method that involved esterification by dehydration under dry conditions. The optimal condition for cross-linking was heating at 130-140 degrees C for 40 hr. Efficacy of the cross-linking was evaluated using enzymatic digestion of 0.01% protease in phosphate buffer at pH 7.4. Collagenous materials without cross-linking were digested completely within 30 min. However, with thermal cross-linking, it required 7 days for digestion. The capacity for holding onto water also was tested. Water content decreased when the cross-link density was increased. As an in vivo experiment, six succinylated collagen sealed vascular grafts treated with thermal cross-linking were implanted in the abdominal aortae of dogs and removed 21 days later. These grafts showed no foreign body reaction, and the collagen layer was almost completely absorbed. A collagen sealed graft cross-linked with formaldehyde used as a control showed a strong foreign body reaction. These results suggest that the physical cross-linking method was suitable for biodegradable biologicals, such as collagenous materials, without the undesirable side effects of chemical cross-linking regents.

Role of lipid aldehydes in cataractogenesis: 4-hydroxynonenal-induced cataract

Free radicals have extremely short half-lives and they readily oxidize lipids and initiate an autocatalytic chain reaction of lipid peroxidation, which leads to the formation of lipid peroxides. The lipid peroxides undergo degradation to form metastable lipid aldehydes such as 4-hydroxynonenal (HNE). We have shown earlier that under hyperglycemia, lipid peroxides increase; and aldose reductase, an enzyme that reduces glucose to sorbitol, efficiently reduces HNE. The purpose of the present studies was thus to investigate the role of HNE in hyperglycemic cataract and understand the mechanism(s) of its prevention by antioxidants and aldose reductase inhibitors. HNE and hyperglycemic cataract were developed by culturing rat lenses in TC-199 medium containing 50 microM HNE and 50 mM glucose, respectively. The effect of an anti-oxidant, trolox, and an aldose reductase inhibitor, sorbinil, on the progression of HNE and hyperglycemic cataract, evaluated by digital image analysis, was followed for 8 and 9 days, respectively. In lenses cultured with HNE, the decrease in transmitted light was 43, 65, and 87% on Days 3, 5, and 8, respectively. Trolox ameliorated the HNE cataract, whereas sorbinil accelerated the progression of HNE cataract and prevented the progression of hyperglycemic cataract. It is concluded that HNE formed under hyperglycemia may play a pivotal role in diabetic cataractogenesis.

Occupational allergic contact dermatitis due to acrylates in Lodz

Among 1619 patients suspected of occupational contact dermatitis examined during the years 1990-1994, sensitivity to acrylates was diagnosed in 9 persons (4 dental technicians, 4 dentists, 1 textile printer). Ethyleneglycol dimethacrylate (5 positive patch tests), methyl methacrylate (4), 2-hydroxyethyl methacrylate (4) and triethyleneglycol dimethacrylate (4) were the most common sensitizers. Comparison of patch test results in dental technicians and dentists indicated that dentists were sensitive to a greater number of (meth)acrylate (acrylate and methacrylate) allergens and also to certain other allergens (metals and rubber additives). Dental technicians were sensitive almost exclusively to methacrylates, while the textile printer only to acrylates.

Persistence of injectable collagen in human urethra: case report

A polypoid lesion was found near the bladder neck during cystoscopy in a woman with urinary incontinence who had undergone periurethral collagen (Contigen) injections 3 years before. She had previously received radiation therapy in addition to a radical vulvectomy for vaginal cancer. On transurethral resection of the lesion, particles of unresorbed collagen material extruded from the capsulated suburothelial space. Histologic evaluation verified the material as the foreign collagen. The persistence of glutaraldehyde cross-linked collagen in our patient was much longer than previously reported and may have been due to effects of previous radiation treatment.

Glutaraldehyde as a fixative in bioprostheses and drug delivery matrices

The use of glutaraldehyde as a fixative in bioprostheses and drug delivery matrices is reviewed. The chemistry of glutaraldehyde cross-linking and its effect on the biological performance of a number of bioprostheses such as tissue heart valves, vascular grafts, pericardial patches, tendon grafts and drug delivery matrices are examined.