This study's aim was to determine the early postoperative expression of proinflammatory cytokines interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) by corneal grafts. BALB/c (n = 90) ...and C57BL/6 (n = 90) murine recipients were grafted with donor corneas from either syngeneic or allogeneic mice. At 7 and 14 days after surgery, corneal grafts were excised and the recipient rims separated from the donor tissue. Corneal segments were cultured and assayed for cytokines by enzyme-linked immunosorbent assay (ELISA). There was profound upregulation in expression of both IL-1alpha and TNF-alpha after corneal transplantation. Among both low-rejecting BALB/c and high-rejecting C57BL/6 hosts, levels of IL-1alpha were significantly (p < 0.01) more marked in allogeneic as compared to syngeneic grafts. TNF-alpha overexpression was similarly more marked in allogeneic as compared to syngeneic grafts in both BALB/c and C57BL/6 hosts, although the difference was generally more marked among high-rejecting C57BL/6 recipients. In the case of both IL-1alpha and TNF-alpha, the principal source of cytokine expression in the transplanted tissue was the recipient rim. There is significant overexpression of both IL-1alpha and TNF-alpha during the first 2 weeks after transplantation in both syngeneic and allogeneic orthotopic corneal grafts. However, whereas in syngeneic grafts cytokine expression generally decreases after the first postoperative week, significantly elevated cytokine levels are sustained in allogeneic grafts, implicating IL-1 and TNF-alpha as mediators of the alloimmune response in corneal transplantation.
Purpose
To compare the outcomes of astigmatic laser in-situ keratomileusis (LASIK) procedures between two different platforms using J
0
and J
45
vector analysis.
Methods
Patients were divided into ...four groups, depending on the type of astigmatism and laser platform on which they were treated. Astigmatism was between 2 and 7 diopters (D). One hundred and thirty-five patients with myopic astigmatism (246 eyes) and 102 patients with mixed astigmatism (172 eyes) underwent unremarkable LASIK correction on Wavelight Allegretto Eye-Q 400Hz and Schwind Amaris 750S laser platform. The preoperative and postoperative sphere, negative cylinder C and axis (ø) of manifest refractions were subjected to vector analysis by calculations of the standard J
0
(cos 4π(ø-90)/360xC/2) and J
45
(sin4π(ø-90)/360xC/2).
Results
Reporting the key results, we found J
0
significantly reduced after LASIK in both groups (
p
< 0.001) but not J
45
. There was no significant association between individual pairs of pre and postoperative J
0
& J
45
values. There was no significant difference between the outcomes of the two platforms.
Conclusions
Wavelight Allegretto 400Hz and Schwind Amaris 750S showed excellent results for treating patients with astigmatism, regardless whether it is mixed or myopic astigmatism. The J
45
did not reduce significantly possibly because of the low number of eyes with oblique astigmatism. There was no genuine difference post-operatively between groups treated on two different laser platforms according to the vector analyses.
Electrospun materials are good candidates for the design of tissue regeneration scaffolds as they can simulate the natural surroundings of tissue cells. The study proposes electrospun ...polycaprolactone (PCL)/cefuroxime (CFU) scaffolds for human cell culture and investigates the influence of the antibiotic content on scaffold morphology, thermal and mechanical properties. The increase in the CFU concentration resulted in the reduction of fiber diameter and number of deformations. It also influenced the reduction of scaffold thermal enthalpies and improved scaffold break strength. With regard to cell growth, the scaffolds showed precedence in greater colonization of the HeLa cells. Finally, these scaffolds showed compatibility with standard human cell lines, and thus they can be used for the repair of damaged tissues.
.
Purpose: To describe a modified graft‐over‐host (MGOH) surgical technique which was used to prevent serious complications in cases of positive vitreal pressure during penetrating keratoplasty ...(PKP) and to compare the endothelial cell density (ECD) loss and clinical outcome between eyes undergoing MGOH or standard PKP.
Methods: In the proposed MGOH technique, the donor graft is sutured over the recipient cornea as soon as signs of positive pressure are noticed, even before cutting the recipient cornea, and the surgery is continued by consecutive cutting of the recipient and continuous suturing of the donor cornea, quadrant by quadrant. Donor grafts were prospectively followed up for the graft clarity, ECD loss and the amount of astigmatism.
Results: Of 220 cases scheduled for standard PKP in years 2009–2011, eight were operated by MGOH technique. Despite the fact that the donor cornea is situated over the recipient almost throughout the whole MGOH procedure, the ECD loss is equal between eyes operated on by MGOH technique and standard PKP, and none of the grafts had primary graft failure. The only disadvantage was an increased amount of astigmatism that was not as significant once the sutures were taken out.
Conclusion: Modified graft‐over‐host technique seems to be a safe and effective method to prevent complications during PKP complicated by positive vitreal pressure.
In this paper, the effect of different collector geometry on the PCL scaffold architecture and cell viability was investigated. PCL scaffolds with antibiotic Cefuroxim
®
, 15%wt. and 20%wt., were ...electrospun and characterized by ATR-FTIR, while thermal stability were observed by DSC and TG. PCL/15%CFU
®
scaffolds were electrospun on six 3D printed collectors, three ribbed and three mesh geometries, to produce the most favourable structure for cells adhesion and proliferation. SEM study and MTT assay revealed that collectors with the widest slot in both ribbed and mesh geometries exhibited the most favourable structure to enhance cells adhesion. In general, cells spreading on the surface and cells viability proved to be better for the ribbed collectors. The study showed that by controlling the collector geometry and the scaffold three-dimensional structure, it is possible to control cell attachment and differentiation and, consequently, to adjust them for the special tissue demands in the regeneration process.
Abstract
Purpose: To evaluate whether the vascular endothelial growth factor A (VEGF-A) in the recipient cornea measured at the time of penetrating keratoplasty (PK) can act as a prognostic factor ...for corneal graft reaction development.
Methods: The study included 25 eyes (of 25 patients) scheduled for PK. According to preoperative clinical finding, patients were divided into three groups: inflammatory with neovascularization (n = 11); inflammatory without neovascularization (n = 7); and non-inflammatory (n = 7). One half of the recipient cornea was analyzed for the levels of VEGF-A protein using a commercial enzyme-linked immunosorbent assay; the other half was analyzed to determine the loci of VEGF-A production by immunohistochemistry. The frequencies of corneal graft reaction and rejection were recorded, together with the improvement of visual acuity. Twenty-five donor corneas obtained from cadaver eyes represented the control group (n = 25).
Results: There was a statistically significant difference in the levels of VEGF-A protein between the recipient corneal buttons obtained from eyes with inflammatory changes and neovascularization, and those from the non-inflammatory group and controls (p < 0.01). The level of VEGF-A was 287.74 pg/ml (standard deviation SD = 129.181) in the inflammatory with corneal neovascularization group, 227.64 pg/ml (SD = 85.590) in the inflammatory without neovascularization group, 115.37 pg/ml (SD = 105.93) in the non-inflammatory group, and 142.28 pg/ml (SD = 93.081) in the control group. Graft reaction/rejection rate was 54.5%/45.5% in the inflammatory with neovascularization group, 14.3%/0% in the inflammatory without neovascularization group, and 14.3%/14.3% in non-inflammatory group. Patients who developed clinical signs of graft reaction during the postoperative follow-up had a significantly higher level of VEGF-A (307.4 pg/ml, SD = 100.058) compared with those without any signs of graft reaction (182.8 pg/ml, SD = 124.987).
Conclusion: Our results suggest that both graft reaction and final graft rejection occur more often in patients with increased levels of VEGF-A in a recipient cornea at the time of PK.
The authors discussed about the problem of special form in astigmatism classification. This special type of astigmatism is the form of obliquely crossed astigmatism. In which the meridians, major and ...minor, are not right angles. In this astigmatism is not possible to prescribing for cylindrical (toric) spectacle lens. Authors describe the Thompson formula for oblique crossed cylinder and observe that this formula is to complicate for calculation new cylinder power. In this reason, the authors create the new formula and simple procedure for this calculation. This simple formula based on vector analysis and read: DM3 = DM2 x cos2 beta.
We sought to determine the efficacy of amniotic membrane transplantation (AMT) in the reconstruction of ocular surface. AMT was performed on 40 eyes with following indications: I, persistent corneal ...ulceration (n = 12); II, impending perforation (n = 6); III, persistent epithelial defect on the corneal graft (n = 6); IV, recurrent pterygia (n = 10), and V, risk of conjunctival scarring (n = 6). Amniotic membrane was prepared from a fresh placenta under sterile conditions, washed with BSS containing penicillin, streptomycin, neomycin and amphotericin B and stored at -80 degrees C in 1:1 InoSol:Glycerol solution. Donor serological test for HIV, HBV and HCV were all negative. Associated surgical procedures according to indication were performed. Healing of the corneal ulcer in Group I was obtained in 67% of eyes at 1-3 weeks after surgery, Group II: AMT was followed by 'a chaud' keratoplasty in 33% and by planned keratoplasty in 67% patients, Group III: healing of the defect in 33% of eyes in 2-5 postoperative weeks, Group IV: no recurrence of pterygium ingrowth in 70% in the follow up period of 6-14 months, and V: 84% of patients had good eye motility without any synechia formation. We concluded that AMT have shown to be effective in enhancing healing of the corneal defects, in prevention of symblepharon formation and recurrent pterygium ingrowth. In case of impending perforation, AMT alone was not a method of treatment but is useful as a first step procedure in preparing the eye for the corneal transplantation.
To investigate the impact of synthetic electrospun polyurethane (PU) and polycaprolactone (PCL) nanoscaffolds, before and after hydrolytic surface modification, on viability and differentiation of ...cultured human eye epithelial cells, in comparison with natural scaffolds: fibrin and human amniotic membrane.
Human placenta was taken at elective cesarean delivery. Fibrin scaffolds were prepared from commercial fibrin glue kits. Nanoscaffolds were fabricated by electrospinning. Limbal cells were isolated from surpluses of human cadaveric cornea and seeded on feeder 3T3 cells. The scaffolds used for viability testing and immunofluorescence analysis were amniotic membrane, fibrin, PU, and PCL nanoscaffolds, with or without prior NaOH treatment.
Scanning electron microscope photographs of all tested scaffolds showed good colony spreading of seeded limbal cells. There was a significant difference in viability performance between cells with highest viability cultured on tissue culture plastic and cells cultured on all other scaffolds. On the other hand, electrospun PU, PCL, and electrospun PCL treated with NaOH had more than 80% of limbal cells positive for stem cell marker p63 compared to only 27%of p63 positive cells on fibrin.
Natural scaffolds, fibrin and amniotic membrane, showed better cell viability than electrospun scaffolds. On the contrary, high percentages of p63 positive cells obtained on these scaffolds still makes them good candidates for efficient delivery systems for therapeutic purposes.
In 25 eyes, age range 60-80 years, in purpose of preoperative treatment prior to cataract surgery, measurements of the radius of curvature as well as main meridians of the anterior and posterior ...corneal surfaces were performed. Average value of the curvature of the anterior corneal surface (R1) was R1 = 7.84 mm, while posterior radius (R2) was 6.4 mm. Main meridian of the anterior corneal surface was in 70% in plus value (+), while postrerior main meridian was always in minus value. It is very important to highlight that main corneal meridians R1 and R2 always cross outside the 90 degrees angle. That is why the combination of the calculation based on the two main meridians superposition (overrefraction) as a form of crossed cylinders has to be calculated (Astigmatismus directus seu obliquus decusatus) using special formula. One of that kind of formulas is Thompson's. Authors want to emphasise the importance of the optical calculation of the posterior corneal surface in the refractive surgery.
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