Attitudes towards urban green during the COVID-19 pandemic via Twitter.

COVID-19 has had economic, social and environmental impacts worldwide. Governments have adopted containment measures to limit the spread of the virus. Urban green spaces (UGSs) were included among the non-essential activities and were consequently closed during the lockdown periods in some countries. This study analysed tweets posted by users to understand the citizens' perception and sentiment in relation to the closure of UGS in Italy. Results revealed that people felt a strong deprivation feeling in relation to the restrictions imposed on UGS access, which limited the number of spaces for supporting mental and physical wellbeing of citizens. Users from urban areas were more affected by the lockdowns and more willing to share thoughts on social media, demonstrating a strong emotionality. Furthermore, findings show that users seemed concerned about their children's health, expressing awareness about the benefits of being in contact with nature. UGS is able to provide services to citizens, and close-to-home parks are fundamental for the community, in particular during a health emergency. The implementation of urban design, which includes green areas to support health and environment challenges, should be addressed by policy-makers to create opportunities for a green and resilient recovery of cities, and prepare for future emergencies.

NLRP3 is involved in long bone edification and the maturation of osteogenic cells.

Overexpression of the nucleotide-binding leucine-rich repeat protein 3 (NLRP3) inflammasome in chronic auto-immune diseases leads to skeletal anomalies, with severe osteopenia due to the activation of osteoclasts. Reproducing this phenotype in Nlrp3 knock-in mice has provided insights into the role of NLRP3 in bone metabolism. We studied the role of NLRP3 in physiological bone development using a complete Nlrp3 knock-out mouse model. We found impaired skeletal development in Nlrp3-/- mice, resulting in a shorter stature than that of Nlrp3+/+  mice. These growth defects were associated with altered femur bone growth, characterized by a deficient growth plate and an osteopenic profile of the trabeculae. No differences in osteoclast recruitment or activity were observed. Instead, Nlrp3-/- femurs showed a less mineralized matrix in the trabeculae than those of Nlrp3+/+  mice, as well as less bone sialoprotein (BSP) expressing hypertrophic chondrocytes. In vitro, primary osteoblasts lacking NLRP3 expression showed defective mineralization, together with the downregulation of BSP expression. Finally, follow-up by micro-CT highlighted the role of NLPR3 in bone growth, occurring early in living mice, as the osteopenic phenotype diminishes over time. Overall, our data suggest that NLRP3 is involved in bone edification via the regulation of hypertrophic chondrocyte maturation and osteoblast activity. Furthermore, the defect appeared to be transitory, as the skeleton recovered with aging.

Movement analysis in early infancy: Towards a motion biomarker of age.

BACKGROUND: Early motor development is characterized by progressive changes in general movements paralleled by a gradual organization of the four limbs' repertoire towards the midline, as shown by computerised movement analysis. AIMS: Our aim was to test the performance of quantitative computerised kinematic indexes as predictors of post-term age in an independent cohort of typically developing subjects at fidgety age, tested cross-sectionally. SUBJECTS: We selected twelve low risk term infants, who were video recorded between 9 and 20 weeks (fidgety age) during one spontaneous movements session. STUDY DESIGN: We correlated post-term age with I)indexes of coordination including interlimb correlation of velocity and position, II)indexes of distance, including interlimb and limb-to- ground, both expressed as linear distance and as probability of midline limbs position III)indexes of global movement quality by calculating Hjorth's activity, mobility and complexity parameters. All indexes were calculated for both upper and lower limbs. RESULTS: Significant positive correlations were found between post-term age and indexes of distance, and probability of occurrence of upper-limb antigravity patterns, and with both indexes of global movement quality. By combining linear and non-linear parameters related to the upper limb kinematics, we determined individual post-term age with a mean error of <1 week (5.2 days). No correlations were found between age and indexes of coordination. CONCLUSIONS: Quantitative computerised analysis of upper-limb movements is a promising predictor of post-term age in typically developing subjects at fidgety age.

Luteal activity and effect of dietary energy restriction on follicular development in lactating cows.

The aim of this research has been to evaluate the presence of anomalies in the ovarian cycle activity during postpartum and to verify whether 72-hr dietary fasting during the dominance phase, the phase before ovulation, might modify the ovarian follicle population. The presence of anomalies in ovarian cycle activity has been evaluated in 30 Italian Friesian cows starting from 20 days postpartum until 211 days of lactation. Long oestrus and brief dioestrus or scarce luteal activity have been the main anomalies found through measuring progesterone concentrations in the whey. Until 100 days of lactation, the BCS values of the problematic animals have been significantly lower than those in animals with normal ovarian activity. After 100 days of lactation, the ovarian anomalies continued to appear despite the fact that all the animals have reached comparable BCS values. Starting from the results of this trial, the effect of 72-hr dietary fasting on dominant follicles has been studied in six cows. Ultrasonography revealed that the diameter of the follicles at 71 days postpartum has been significantly lower than at 181 days. A 72-hr dietary restriction at 101 and 211 days postpartum did not affect the size of the dominant follicle. However, at 101 days postpartum, half of the animals presented follicular cysts. The effect of fasting differed if the animal has been in early postpartum or 211 days of lactation. Further researches are necessary to understand how different metabolic conditions can modify the follicular population but on the other hand the study shows the utility for farmers and field veterinarians of monitoring the resumption of the ovarian cycle postpartum through the whey progesterone concentrations.

An aqueous one-pot route to gold/quantum rod heterostructured nanoparticles functionalized with DNA.

We report an original approach exploiting the photoelectrochemical properties of quantum rods and the versatility of Au(I) organometallic chemistry to control DNA surface grafting. This one-pot aqueous approach provides Janus biofunctionalized nanoparticles, the assembly of which should results in the emergence of synergistic properties.

Replacement of CTAB with peptidic ligands at the surface of gold nanorods and their self-assembling properties.

Herein, we describe the self-assembling of gold nanorods (GNRs) induced during the ligand exchange at their surface. An exchange reaction between tricysteine PEGylated peptidic ligands and cetyltrimethylammonium bromide (CTAB)-protected gold nanorods is conducted. We demonstrated that the terminal group charge (positively or negatively charged) and the hydrophobicity of the peptidic ligands (bearing or not an undecanoyl chain) strongly affects the self-organization of the GNRs occurring in solution. Adjusting the amount of short PEGylated peptides causes a self-organization of the gold nanorods in solution, resulting in a red- or blue-shift of the plasmon bands. The decrease of their surface charge and the self-assembling in solution were first shown by zetametry, by Dynamic Light Scattering and UV-spectroscopy. Thanks to Small Angle X-ray Scattering experiments and Transmission Electron Microscopy images, the self-organization of the nanorods in solution was clearly demonstrated and correlated to the spectroscopic change in absorbance. Conversely, in the case of longer PEGylated peptidic ligands including an undecanoyl chain, the GNRs are particularly stable against aggregation for several days after purification. By controlled drying on a substrate, we showed their ability to self-organize into well-defined ordered structures making them very attractive as building blocks to design optical materials.

Synthesis and enzymatic photo-activity of an O2 tolerant hydrogenase-CdSe@CdS quantum rod bioconjugate.

This communication reports on the preparation of stable and photo-active nano-heterostructures composed of O2 tolerant [NiFe] hydrogenase extracted from the Aquifex aeolicus bacterium grafted onto hydrophilic CdSe/CdS quantum rods in view of the development of H2/O2 biofuel cells. The resulting complex is efficient towards H2 oxidation, displays good stability and new photosensitive properties.

The effect of an acute energy deficit on the hormone profile of dominant follicles in dairy cows.

The effect of an acute energy deficit on the hormone balance of dominant follicles was studied in six normally-cycling, high-yielding Italian Friesian cows at 60 and 90 days after calving. At 60 days after calving, the cows, which had been fed according to their maintenance and production requirements, were synchronized and follicular fluid was collected from the dominant follicles under ultrasound guidance. At 90 days after calving, the same protocol was used on the same cows, which had been subjected to an acute dietary restriction since the day of the second prostaglandin treatment for synchronization. At the follicular level, the dietary restriction caused a significant reduction (P < 0.05) in the concentration of estradiol-17beta and a significant increase (P < 0.05) in NEFA. There were no significant differences in follicular diameter, follicular concentrations of progesterone, and Insulin-like Growth Factor-I (IGF-I). The amount of IGFBP2 and IGFBP3 in follicular fluid increased. The results suggest that an acute dietary restriction induces substantial changes at the dominant follicle level, despite the fact that the recruitment and selection phase occurred before the cows' diet was restricted.

Effect of insemination time of frozen semen on incidence of uterine fluid in mares.

Ninety five mares were inseminated with frozen semen either within 12 h before ovulation or within 8 h after ovulation. The effect of preovulatory versus postovulatory insemination (AI) on the subsequent detection of uterine fluid was studied. The overall pregnancy rate was 43% and this was not significantly influenced by preovulatory or postovulatory insemination. When mares were first examined 12 h after AI, 18 of 52 mares (35%) had accumulated uterine fluid. However, when mares were first examined 18 to 24 h after AI, only 6 of 43 mares (14%) had uterine fluid. Presence of intrauterine fluid significantly lowered pregnancy rates. Timing of insemination did not affect incidence of uterine fluid. Serum concentrations of estrogen and progesterone at time of insemination did not influence uterine clearance or pregnancy rates, but both hormones were higher at preovulatory than at postovulatory inseminations. We concluded that there was no evidence that postovulatory inseminations would predispose mares to persistence of uterine fluid after AI.

Mathematical models of picosecond laser keratomileusis for high myopia.

PURPOSE: Picosecond laser keratomileusis (PLK) is a refractive surgical procedure in which an intrastromal lenticle is created using the Nd:YLF picosecond laser and removed by lifting the anterior flap in the cornea. The purpose of this study was to assess the predictability of picosecond laser keratomileusis for high myopia. METHODS: The results from a recent clinical series of non-sighted patients who had undergone picosecond laser keratomileusis with the Nd:YLF picosecond laser were retrospectively simulated with two mathematical models. In one model, the change in corneal curvature resulting from the collapse of a lenticular intrastromal cavity was predicted from a geometric analysis. A second model was developed using the finite element method. The results of both predictive models were compared to the clinical results at 1 and 6 months following surgery. RESULTS: An average -13.30 D of flattening (range, -6.80 to -20.50 D) was measured at 6 months. The geometric model predicted an average correction of -23.10 D (range, -18.00 to -34.00 D), whereas the finite element model predicted an average curvature change of -17.40 D (range, -14.50 to -22.50 D). An average decrease in central pachymetry of 91 microm was measured at 6 months, as compared to a predicted decrease in thickness of 112 microm. CONCLUSIONS: The outcome of picosecond laser keratomileusis for high myopia predicted using a finite element based model shows greater change in the corneal curvature and corneal thickness compared to clinical results. The relatively thick lenticules that are removed for high myopia cause considerable deformational changes in the cornea, which preclude the use of a purely geometric/optical approach for predicting the resultant corneal curvature changes.

Proliferative inflammatory atrophy of the prostate: implications for prostatic carcinogenesis.

Proliferation in the setting of longstanding chronic inflammation appears to predispose to carcinoma in the liver, large bowel, urinary bladder, and gastric mucosa. Focal prostatic atrophy, which is associated with chronic inflammation, is highly proliferative (Ruska et al, Am J Surg Pathol 1998, 22:1073-1077); thus the focus of this study was to more fully characterize the phenotype of the atrophic cells to assess the feasibility of the proposal that they may be targets of neoplastic transformation. The pi-class glutathione S-transferase (GSTP1), a carcinogen-detoxifying enzyme, is not expressed in >90% of prostate carcinomas (CaPs). GSTP1 promoter hypermethylation, which appears to permanently silence transcription, is the most frequently detected genomic alteration in CaP (Lee et al, Proc Natl Acad Sci USA 1994, 91:11733-11737; >90% of cases). In high-grade prostatic intraepithelial neoplasia (PIN), this alteration is present in at least 70% of cases (Brooks et al, Cancer Epidemiol Biomarkers Prev, 1998, 7:531-536). Although normal-appearing prostate secretory cells rarely express GSTP1, they remain capable of expression, inasmuch as GSTP1 promoter hypermethylation is not detected in normal prostate. Fifty-five lesions from paraffin-embedded prostatectomy specimens (n = 42) were stained for GSTP1, using immunohistochemistry. Adjacent sections were stained for p27(Kip1), Ki-67, androgen receptor (AR), prostate-specific antigen (PSA), prostate-specific acid phosphatase (PSAP), Bcl-2, and basal cell-specific cytokeratins (34betaE12). With normal prostate epithelium as the internal standard, staining was scored for each marker in the atrophic epithelium. The lesions showed two cell types, basal cells staining positive for 34betaE12, and atrophic secretory-type cells staining weakly negative for 34betaE12. All lesions showed elevated levels of Bcl-2 in many of the secretory-type cells. All lesions had an elevated staining index for the proliferation marker Ki-67 in the secretory layer and decreased expression of p27(Kip1), a finding reminiscent of high-grade PIN (De Marzo et al, Am J Pathol 1998, 153:911-919). Consistent with partial secretory cell differentiation, the luminal cells showed weak to moderate staining for androgen receptor and the secretory proteins PSA and PSAP. All atrophic lesions showed elevated GSTP1 expression in many of the luminal secretory-type cells. Because all lesions are hyperproliferative, are associated with inflammation, and have the distinct morphological appearance recognized as prostatic atrophy, we suggest the term "proliferative inflammatory atrophy" (PIA). Elevated levels of GSTP1 may reflect its inducible nature in secretory cells, possibly in response to increased electrophile or oxidant stress. Elevated Bcl-2 expression may be responsible for the very low apoptotic rate in PIA and is consistent with the conclusion that PIA is a regenerative lesion. We discuss our proposal to integrate the atrophy and high-grade PIN hypotheses of prostate carcinogenesis by suggesting that atrophy may give rise to carcinoma either directly, as previously postulated, or indirectly by first developing into high-grade PIN.

An N-terminal EF hand-like motif modulates ion transport by Pmr1, the yeast Golgi Ca(2+)/Mn(2+)-ATPase.

Pmr1, a novel member of the family of P-type ATPases, localizes to the Golgi compartment in yeast where it provides Ca(2+) and Mn(2+) for a variety of normal secretory processes. We have previously characterized Ca(2+) transport in isolated Golgi vesicles, and described an expression system for the analysis of Pmr1 mutants in a yeast strain devoid of background Ca(2+) pump activity [Sorin, A., Rosas, G., and Rao, R. (1997) J. Biol. Chem. 272, 9895-9901]. Here we show, using recombinant bacterial fusions, that an N-terminal EF hand-like motif in Pmr1 binds Ca(2+). Increasing disruptions of this motif led to progressive loss of pump function; thus, the single point mutations D51A and D53A retained pump activity but with drastic reductions in the affinity for Ca(2+) transport, while the double mutant was largely unable to exit the endoplasmic reticulum. In-frame deletions of the Ca(2+)-binding motif resulted in complete loss of function. Interestingly, the single point mutations conferred differential affinities for transport of Ca(2+) and Mn(2+) ions. Further, the proteolytic stability of the catalytic ATP-binding domain is altered by the N-terminal mutations, suggesting an interaction between these two regions of polypeptide. These studies implicate the N-terminal domain of Pmr1 in the modulation of ion transport, and may help elucidate the role of N-terminal metal-binding sites of Cu(2+)-ATPases, defective in Wilson and Menkes disease.

Abnormal regulation of DNA methyltransferase expression during colorectal carcinogenesis.

Somatic changes in CpG dinucleotide methylation occur quite commonly in human cancer cell DNA. Relative to DNA from normal human colonic cells, DNA from human colorectal cancer cells typically displays regional CpG dinucleotide hypermethylation amid global CpG dinucleotide hypomethylation. The role of the maintenance DNA methyltransferase (DNMT1) in the acquisition of such abnormal CpG dinucleotide methylation changes in colorectal cancer cells remains controversial; in one study, 60-200-fold increases in DNMT1 mRNA expression were detected in colorectal polyps and cancers relative to normal colonic tissue [W. S. El-Deiry et al., Proc. Natl. Acad. Sci. USA, 88: 3470-3474, 1991], whereas in another study, only small increases in DNMT1 mRNA expression, commensurate with differences in cell proliferation accompanying colonic tumorigenesis, were observed [P. J. Lee et al., Proc. Natl. Acad. Sci. USA, 93: 10366-10370, 1996]. To definitively ascertain whether abnormal DNMT1 expression might accompany human colorectal carcinogenesis, we subjected a series of normal and neoplastic colonic tissues to immunohistochemical staining using a polyclonal antiserum raised against a DNMT1 polypeptide. A concordance of DNMT1 expression with the expression of PCNA and other cell proliferation markers, such as Ki-67 and DNA topoisomerase IIalpha, was observed in normal colonic epithelial cells and in cells comprising other normal epithelia and lymphoid tissues. The polypeptide p21, which has been reported to undermine DNMT1 binding to proliferating cell nuclear antigen at DNA replication sites, was not expressed by normal colonic cells containing DNMT1 and other cell proliferation markers. In adenomatous polyps, although DNMT1 expression coincided with the expression of other cell proliferation markers, many DNMT1-expressing cells also expressed p21. The fidelity of DNMT1 expression was further undermined in colorectal carcinomas, in which a striking heterogeneity in DNMT1 expression, with some carcinoma cells containing very high DNMT1 levels and others containing very low DNMT1 levels, was observed. These results indicate that human colorectal carcinogenesis is accompanied by a progressive dysregulation of DNMT1 expression and suggest that abnormalities in DNMT1 expression may contribute to the abnormal CpG dinucleotide methylation changes characteristic of human colorectal carcinoma cell DNA.

Induction of vacuolar Ca2+-ATPase and H+/Ca2+ exchange activity in yeast mutants lacking Pmr1, the Golgi Ca2+-ATPase.

We have analyzed Ca2+ transport activity in defined subcellular fractions of an isogenic set of wild-type and mutant yeast. The results, together with measurements of polypeptide expression levels and promoter::reporter gene activity, show that the Golgi Ca2+-ATPase, Pmr1, is the major Ca2+ pump under normal growth conditions. In the absence of Pmr1, we show a massive, calcineurin-dependent compensatory induction of the vacuolar Ca2+-ATPase, Pmc1. In addition, H+/Ca2+ exchange activity, that may be distinct from the vacuolar exchanger Vcx1, is also increased.

Clinical analysis of the neodymium:YLF picosecond laser as a microkeratome for laser in situ keratomileusis. Partially Sighted Eye Study.

PURPOSE: To evaluate the use of a picosecond neodymium:YLF (Nd:YLF) laser as a nonmechanical intrastromal microkeratome. SETTING: Universita Cattolica del Sacro Cuore, Rome, Italy. METHODS: An intrastromal spiral disc pattern of picosecond laser pulses was used to create a corneal flap for laser in situ keratomileusis (LASIK) in 14 partially sighted eyes. RESULTS: Flaps with a 6.0 mm diameter and 180 to 200 microns depth were successfully created in most cases. The underlying stroma was treated with a Lambda Physik excimer laser using a 3.5 to 4.5 mm optical zone. Patients were divided into 3 groups for target corrections of 5.0, 10.0, and 15.0 diopters of myopia. Good corneal clarity and refractive undercorrection were recorded in each group 6 months postoperatively. The undercorrection was due in part to the limited optical zone of the laser's delivery system. Some flap decentration was noted. CONCLUSION: This pilot study indicates that the Nd:YLF picosecond laser may be clinically applied for creating corneal flaps for LASIK. Further refinements of the laser delivery system will include enlargement of the flap diameter and improvements in flap centration. The use of a femtosecond laser may expand the capabilities and precision of this technology.

The picosecond laser for nonmechanical laser in situ keratomileusis.

PURPOSE: To introduce the clinical use of the Nd:YLF picosecond laser as a nonmechanical microkeratome. METHODS: A commercially available Nd:YLF picosecond laser (25 microJ/pulse, 30 psec, 1053 nm) was used to deliver intrastromal pulses of focused high power laser light to generate a flap for laser in situ keratomileusis (LASIK) and perform picosecond laser keratomileusis (PLK) in two partially sighted patients with high myopia. RESULTS: Case #1: A 6 mm, 150 microns flap for LASIK was successfully created and the underlying stroma treated with an excimer laser for a target correction of -15.00 D of myopia. Good corneal clarity and a refractive change of -14.00 D was recorded 2 months postoperatively. Case #2: Both eyes of a high myope (-22.00 D right eye, -21.50 D left eye) underwent picosecond laser keratomileusis, removing a 3.2 mm diameter lenticule of 120 microns thickness under a 200 microns flap. Postoperative refraction was -2.00 D at 7 months in the right eye and -0.75 D at 2 months in the left eye with improvement of spectacle-corrected visual acuity from 20/200 to 20/70 in each eye. CONCLUSION: The Nd:YLF picosecond laser can be safely used in creating a corneal flap for LASIK and in performing picosecond laser keratomileusis for high myopia. Future refinements in the laser will include a larger flap diameter and femtosecond pulsing capability.

Intrastromal photorefractive keratectomy for myopia by Nd:YLF picosecond laser.

BACKGROUND: An intrastromal photorefractive keratectomy (ISPRK) by Nd:YLF Picoseconds Laser has been performed on 17 eyes with corrected visual acuity of 20/200 or worse. The purpose of this study was to study the safety and effectiveness of ISPRK using different laser parameters. METHODS: The Neodymiun Yttrium Lithium Fluoride laser system (Nd:YLF) was used to perform the myopic treatment. We studied the effect of pattern depth, the numbers of patterns, the thickness of a single spiral pattern, the distance between two patterns along Z axis, the pattern curvature perpendicular to the Z axis, the energy, the spatial density, and the repetition frequency of the laser pulse. RESULTS: The laser treatment was completed in 12 patients. In the first group at 180 days postoperatively we did not find corneal opacities, anterior chamber or lens opacities. Pupil diameter and reactivity, endothelial cell density, and IOP were normal. Pachymetry showed an average reduction of the central corneal thickness of 99 microns (+/- 14.7 SD). Topography showed an average reduction of the corneal dioptric power of 2 D (+/- 0.4 SD). In the second group at 120 days postoperatively findings were similar. Pachymetry showed an average reduction of the central corneal thickness of 118.5 mu (+/- 12.5 SD). Topography showed an average reduction of the corneal dioptric power of 2.4D (+/- 0.9 SD). CONCLUSIONS: It is possible to change the corneal power by reducing the corneal thickness with the Nd:YLF laser but the predictability of the result is unknown. Because Bowman's layer is intact, there is no scarring or haze.

Effect of HIV-1 peptide presentation on the affinity constants of two monoclonal antibodies determined by BIAcore technology.

We studied two monoclonal antibodies (MAbs 9-11 and 41-1) which are specific for dominant and conserved epitopes located on HIV-1 transmembrane Gp41. These MAbs recognize both Gp41 and a synthetic HIV-1 envelope peptide (39GC) which is a fragment of Gp41. The interactions between MAbs 9-11 and 41-1 and 39GC either coupled to a sensor chip or to alkaline phosphatase were investigated using BIAcore technology. The association and dissociation rate constants as well as the affinity constants were determined. BIAcore technology allows real-time determination of the interaction between two molecules without the need for any labeling, neither isotopic nor enzymatic. The peptide 39GC was immobilized by coupling to dextran on the BIAcore biosensor through a disulfide bond with a cysteine residue added to the N-terminus of the synthetic peptide. The two native cysteine residues located in the loop of Gp41 were protected by ethylcarbamoyl residues (CONHC2H5); this chemical modification prevented the formation of the S-S bridge and in particular the internal loop. We specifically studied the interaction between the MAbs and either the protected peptide or the peptide whose cysteine residues had been deprotected in situ by alkaline treatment. The results showed that MAb 41-1 recognized 39GC either protected (Ka = 7.6 x 10(6) M-1) or unprotected (Ka = 1.48 x 10(8) M-1), whereas MAb 9-11 recognized only the unprotected form (Ka = 2.18 x 10(8) M-1). Our results suggest that the epitope MAb 9-11 is directed against a part of the peptide sequence which includes the two native cysteines. The difference in affinity observed for MAb 41-1 between the protected and the unprotected forms of 39GC was found to be due to a lower rate of dissociation for unprotected 39GC; these results illustrate the importance of peptide conformation on antibody recognition and might be explained by a conformational change due to reconstitution of the internal loop following deprotection of the thiol groups. MAbs 9-11 and 41-1 also recognized 39GC conjugated to alkaline phosphatase and deprotected. We observed a difference between the rate constants for MAb 41-1 binding to free peptide and its binding to the peptide-enzyme conjugate which might be due to changes in peptide flexibility. In contrast, the rate constants of MAb 9-11 were the same in both experiments, suggesting that the rigidity of the internal loop prevents changes in 9-11 epitope conformation.

Osteo-odonto-keratoprosthesis. Description of surgical technique with results in 85 patients.

Osteo-odonto-keratoprosthesis is a technique designed for patients with severe corneal opacification who would be at high risk of graft rejection should donor tissue transplantation be performed. Because of the isolation of the prosthetic implant from the tissues that the technique provides, the authors are of the opinion that it is the only viable option in such patients. The visual outcome and complications of the procedure in a series of 85 cases are presented.

Strampelli's osteo-odonto-keratoprosthesis. Clinical and histological long-term features of three prostheses.

The histological features are reported of osteo-odonto-acrylic laminae removed from three patients who for differing underlying causes received Strampelli's osteo-odonto-keratoprostheses (OOK) 20, 16, and 12 years previously. It appears that preservation of the alveolar-dental ligament plays a definitive role in the maintenance of the prosthesis. If this tissue undergoes necrosis as a consequence of an inflammatory disease the implanted material is eventually lost. However when no such event occurs the OOK is well preserved and well tolerated even 20 years after implantation.