Understanding genomic medicine for thoracic aortic disease through the lens of induced pluripotent stem cells

Thoracic aortic disease (TAD) is often silent until a life-threatening complication occurs. However, genetic information can inform both identification and treatment at an early stage. Indeed, a diagnosis is important for personalised surveillance and intervention plans, as well as cascade screening of family members. Currently, only 20% of heritable TAD patients have a causative mutation identified and, consequently, further advances in genetic coverage are required to define the remaining molecular landscape. The rapid expansion of next generation sequencing technologies is providing a huge resource of genetic data, but a critical issue remains in functionally validating these findings. Induced pluripotent stem cells (iPSCs) are patient-derived, reprogrammed cell lines which allow mechanistic insights, complex modelling of genetic disease and a platform to study aortic genetic variants. This review will address the need for iPSCs as a frontline diagnostic tool to evaluate variants identified by genomic discovery studies and explore their evolving role in biological insight through to drug discovery.

Extracellular macrostructure anisotropy improves cardiac tissue-like construct function and phenotypic cellular maturation

Regenerative cardiac tissue is a promising field of study with translational potential as a therapeutic option for myocardial repair after injury, however, poor electrical and contractile function has limited translational utility. Emerging research suggests scaffolds that recapitulate the structure of the native myocardium improve physiological function. Engineered cardiac constructs with anisotropic extracellular architecture demonstrate improved tissue contractility, signaling synchronicity, and cellular organization when compared to constructs with reduced architectural order. The complexity of scaffold fabrication, however, limits isolated variation of individual structural and mechanical characteristics. Thus, the isolated impact of scaffold macroarchitecture on tissue function is poorly understood. Here, we produce isotropic and aligned collagen scaffolds seeded with embryonic stem cell derived cardiomyocytes (hESC-CM) while conserving all confounding physio-mechanical features to independently assess the effects of macroarchitecture on tissue function. We quantified spatiotemporal tissue function through calcium signaling and contractile strain. We further examined intercellular organization and intracellular development. Aligned tissue constructs facilitated improved signaling synchronicity and directional contractility as well as dictated uniform cellular alignment. Cells on aligned constructs also displayed phenotypic and genetic markers of increased maturity. Our results isolate the influence of scaffold macrostructure on tissue function and inform the design of optimized cardiac tissue for regenerative and model medical systems.

Epicardially secreted fibronectin drives cardiomyocyte maturation in 3D-engineered heart tissues

Ischemic heart failure is due to irreversible loss of cardiomyocytes. Preclinical studies showed that human pluripotent stem cell (hPSC)-derived cardiomyocytes could remuscularize infarcted hearts and improve cardiac function. However, these cardiomyocytes remained immature. Incorporating hPSC-derived epicardial cells has been shown to improve cardiomyocyte maturation, but the exact mechanisms are unknown. We posited epicardial fibronectin (FN1) as a mediator of epicardial-cardiomyocyte crosstalk and assessed its role in driving hPSC-derived cardiomyocyte maturation in 3D-engineered heart tissues (3D-EHTs). We found that the loss of FN1 with peptide inhibition F(pUR4), CRISPR-Cas9-mediated FN1 knockout, or tetracycline-inducible FN1 knockdown in 3D-EHTs resulted in immature cardiomyocytes with decreased contractile function, and inefficient Ca²⁺ handling. Conversely, when we supplemented 3D-EHTs with recombinant human FN1, we could recover hPSC-derived cardiomyocyte maturation. Finally, our RNA-sequencing analyses found FN1 within a wider paracrine network of epicardial-cardiomyocyte crosstalk, thus solidifying FN1 as a key driver of hPSC-derived cardiomyocyte maturation in 3D-EHTs.

Inducible apelin receptor knockdown reduces differentiation efficiency and contractility of hESC-derived cardiomyocytes

AIMS

The apelin receptor, a G protein-coupled receptor, has emerged as a key regulator of cardiovascular development, physiology, and disease. However, there is a lack of suitable human in vitro models to investigate the apelinergic system in cardiovascular cell types. For the first time we have used human embryonic stem cell-derived cardiomyocytes (hESC-CMs) and a novel inducible knockdown system to examine the role of the apelin receptor in both cardiomyocyte development and to determine the consequences of loss of apelin receptor function as a model of disease.

METHODS AND RESULTS

Expression of the apelin receptor and its ligands in hESCs and hESC-CMs was determined. hESCs carrying a tetracycline-inducible short hairpin RNA targeting the apelin receptor were generated using the sOPTiKD system. Phenotypic assays characterized the consequences of either apelin receptor knockdown before hESC-CM differentiation (early knockdown) or in 3D engineered heart tissues as a disease model (late knockdown). hESC-CMs expressed the apelin signalling system at a similar level to the adult heart. Early apelin receptor knockdown decreased cardiomyocyte differentiation efficiency and prolonged voltage sensing, associated with asynchronous contraction. Late apelin receptor knockdown had detrimental consequences on 3D engineered heart tissue contractile properties, decreasing contractility and increasing stiffness.

CONCLUSIONS

We have successfully knocked down the apelin receptor, using an inducible system, to demonstrate a key role in hESC-CM differentiation. Knockdown in 3D engineered heart tissues recapitulated the phenotype of apelin receptor down-regulation in a failing heart, providing a potential platform for modelling heart failure and testing novel therapeutic strategies.

A single-cell comparison of adult and fetal human epicardium defines the age-associated changes in epicardial activity

Re-activating quiescent adult epicardium represents a potential therapeutic approach for human cardiac regeneration. However, the exact molecular differences between inactive adult and active fetal epicardium are not known. In this study, we combined fetal and adult human hearts using single-cell and single-nuclei RNA sequencing and compared epicardial cells from both stages. We found that a migratory fibroblast-like epicardial population only in the fetal heart and fetal epicardium expressed angiogenic gene programs, whereas the adult epicardium was solely mesothelial and immune responsive. Furthermore, we predicted that adult hearts may still receive fetal epicardial paracrine communication, including WNT signaling with endocardium, reinforcing the validity of regenerative strategies that administer or reactivate epicardial cells in situ. Finally, we explained graft efficacy of our human embryonic stem-cell-derived epicardium model by noting its similarity to human fetal epicardium. Overall, our study defines epicardial programs of regenerative angiogenesis absent in adult hearts, contextualizes animal studies and defines epicardial states required for effective human heart regeneration.

High resolution single cell analysis of the developing human heart

 

The human heart is composed of various cell types with distinct embryonic origins and functions. Having an understanding of the components of the developing heart at a molecular level should provide better insights into its function in health and disease. Current single cell studies of human fetal hearts are limited by low cell numbers and poor cell type resolution. Here, we aimed to increase the number of cells studied while adding a spatial resolution. We analysed human hearts aged between post conception weeks of 8 and 11, where apex and base in each were processed, providing spatial resolution on cells constituting the myocardium and the great vessels. Our analysis suggests 6 main cell types in the developing hearts with a total of 28 subtypes and provides a differential expression signature for similar cell types with different origins and anatomical locations, including the smooth muscle cells and endothelial cells of the myocardium and the great vessels. Through immunohistochemistry, we validated our findings on these subtypes, as well as on the cells that were less clearly described before, such sinoatrial node cells or resident macrophages. Cell to cell interaction analysis inferred distinct molecular crosstalk across subtypes, including the cells of the great vessels or the vessels of the myocardium. Our findings suggest a list of transcription factors that might be involved in governing the identity of these cells. Collectively, our analysis provides a better understanding of human heart development, and will inform studies into disease modelling and disease progression.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Abstract P1015: Construction Of A Pro-cardiogenic Extracellular Matrix: How Stem-cell Derived Epicardium Enhances Cardiac Regeneration Through Fibronectin

Background: Human embryonic stem cell-derived epicardium (hESC-Epis) has been shown to improve the function of hESC-derived cardiomyocytes (hESC-CM) in vitro and post-transplantation into animal myocardial infarction models. However, the underlying mechanisms mediating these effects remain poorly characterised. Bulk RNA sequencing of hESC-Epis suggests a role for genes related to extracellular matrix remodeling in mediating these effects, with fibronectin (FN1) being highly implicated.

Study Objective: To examine the role of FN1 in hESC-CM/Epi crosstalk through gain and loss of function studies.

Methods: A tetracycline inducible FN1 knockdown system was used on hESC-CMs and Epis within the setting of 3D-engineered heart tissue. Changes in contractility and calcium handling were measured. Recombinant human plasma FN1 (rhFN) was then used to determine the effect of FN1 supplementation on hESC-CM function.

Results: FN1 knockdown in hESC-Epis resulted in significant abrogation of the beneficial effects on hESC-CM force generation and calcium handling. Knockdown of FN1 in hESC-CMs however significantly attenuated contractility of the hESC-CMs but had no effects on calcium handling. When rhFN was added to hESC-CMs in increasing doses, hESC-CM contractility was improved in a dose dependent fashion to the same extent as seen with hESC-Epis co-cultures. However, rhFN supplementation did not result in significant improvements in calcium handling.

Conclusions: hESC-CM and Epi crosstalk improving hESC-CM function may rely heavily on the presence of FN1. FN1 secreted by both cell types are shown to be of importance in this crosstalk with artificial supplementation of rhFN being able to recapitulate some beneficial effects of hESC-Epis on hESC-CMs. Further studies are required to determine the role of specific isoforms of secreted FN1 on hESC-CM maturity and what mechanism underlies these effects. This opens up the possibility of improving cell-based therapy for heart failure post-myocardial infarction using recombinant FN1 supplementation.

Abstract P1028: The Epicardium As The Conductor Of Cardiovascular Cells In Cardiac Regeneration

Regenerative cardiovascular medicine is emerging as a promising therapeutic alternative to heart transplantation in patients suffering from chronic heart failure. Although promising, challenges to cell therapy for cardiac repair remain, including cell survival, maturation, graft size, revascularisation, and immunogenicity. It has recently been shown that co-transplantation of human embryonic stem cell (hESC)-derived epicardial cells (EPI) with hESC-derived cardiomyocytes (CM) improves cardiac repair processes with respect to engraftment, cell maturation, and graft and host vascularisation. One plausible explanation for the observed benefits of co-transplantation is paracrine-mediated effects. While RNA sequencing data has been used to identify putative players in hESC-EPIs, little is known about their involvement in mediating hESC-CM maturation and revascularization, in particular in communication with endothelial cells (EC). Here, the role of paracrine signalling in hESC-EPI-mediated promotion of hESC-CM maturation and angiogenesis is being investigated with an emphasis on the involvement of extracellular vesicles (EVs). hESC-EPI-EVs improved responsiveness to pacing and coordination of contraction in vitro in hESC-CM cell culture and engineered heart tissues (EHTs). Moreover, hESC-EPI-EVs and hESC-EPI supernatant excluding EVs independently promoted tube formation in in vitro gel-based angiogenesis assays. hESC-EPI supernatant excluding EVs also promoted EC proliferation in MTS assays and EC migration in wound closure assays. Characterisation of the hESC-EPI-EV-cargo on a protein level revealed candidate factors involved in cardiac repair processes. Together with hESC-EPI-EV miRNA-sequencing and hESC-EPI gene expression data key paracrine signalling pathways and candidate factors to manipulate them are being identified and investigated in in vitro angiogenesis and CM maturation assays. Promising angiogenesis promoting candidates are being validated in vivo using yolk-sac membrane and chorioallantoic membrane assays. Identification of the paracrine signalling pathways involved would make it possible to effectively address selected cardiac repair processes, resulting in new approaches to therapy.

Abstract P2064: High Resolution Single Cell Analysis Of The Developing Human Heart

The human heart is composed of various cell types with distinct embryonic origins and functions. Having an understanding of the components of the developing heart at a molecular level should provide better insights into its function in health and disease. Current single cell studies of human fetal hearts are limited by low cell numbers and poor cell type resolution. Here, we aimed to increase the number of cells studied while adding a spatial resolution. We analysed human hearts aged between post conception weeks of 8 and 11, where apex and base in each were processed, providing spatial resolution on cells constituting the myocardium and the great vessels. Our analysis suggests 6 main cell types in the developing hearts with a total of 28 subtypes and provides a differential expression signature for similar cell types with different origins and anatomical locations, including the smooth muscle cells and endothelial cells of the myocardium and the great vessels. Through immunohistochemistry, we validated our findings on these subtypes, as well as on the cells that were less clearly described before, such sinoatrial node cells or resident macrophages. Cell to cell interaction analysis inferred distinct molecular crosstalk across subtypes, including the cells of the great vessels or the vessels of the myocardium. Our findings suggest a list of transcription factors that might be involved in governing the identity of these cells. Collectively, our analysis provides a better understanding of human heart development, and will inform studies into disease modelling and disease progression.

The effects of posterior continuous curvilinear capsulorhexis on contrast sensitivity

PURPOSE

We aimed at evaluating the effects of posterior continuous curvilinear capsulorhexis (PCCC) on contrast sensitivity.

MATERIALS AND METHODS

In this prospective, randomized, bilateral clinical study, 40 eyes of 20 patients who underwent bilateral cataract surgery were included. The phacoemulsification machine, viscoelastic substances, surgical tools, and intraocular lenses (IOLs) were the same for both eyes. The only difference was that we conducted the PCCC procedure before IOL implantation to one of the eyes of the patients. The selection of the eye that underwent the PCCC procedure was decided randomly.

RESULTS

The mean photopic contrast sensitivity values at spatial frequencies of 1.5, 3, 6, 12, and 18 cpd (cycles per degree) were 41.55, 59.90, 61.25, 32.35, and 9.75, respectively, and for the control group these values were 39.05, 56.60, 57.95, 29.80, and 8.75, respectively. The mean mesopic contrast sensitivity values at special frequencies of 1.5, 3, 6, 12, and 18 cpd were 41.20, 54.75, 55.55, 31.70, and 9.00, respectively, and for the control group these values were 38.35, 51.70, 52.15, 30.05, and 8.00, respectively. The mean contrast sensitivity values of the eyes that underwent the PCCC procedure were slightly better than the fellow eyes at all spatial frequencies, but the difference was statistically insignificant (P>0.05).

CONCLUSIONS

In early post-operative period, the PCCC procedure exerts some positive effects on contrast sensitivity although these effects are statistically insignificant.

Neoadjuvant dose-dense docetaxel, carboplatinum, and trastuzumab (ddTCH) chemotherapy for HER2 overexpressing breast cancer

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Background: Neoadjuvant chemotherapy for locally advanced breast cancer was shown to improve the complete pathologic (pCR) and clinical response (cCR) as well as the disease free survival (DFS). Docetaxel, cisplatin, and trastuzumab given every 21 days in her2-positive breast cancer demonstrated a pCR rate of 23%. The concept of dose dense chemotherapy regimens has attracted much attention and we hypothesized that dose-dense regimen would further improve pCR, cCR and would maintain the safety profile while being a suitable regimen for outpatient administration. Methods: 48 patients with stage II/III HER2-positive breast cancer were prospectively enrolled on a clinical trial of a neoadjuvant regimen consisting of docetaxel 70 mg/m2 on days 1, 15, 29, and 43; carboplatinum at an AUC of 6 on days 1, 15, 29, and 43; trastuzumab 4 mg/kg on day 1 and 2 mg/kg weekly x 10 starting on day 8; peg-filgastrim 6 mg on days 2, 16, 30, and 44. Results: The median age was 50 years (range 30–78). 52% of patients were premenopausal, 63% and 22% were of Hispanic and African descent, respectively. Estrogen receptor was positive in 52% patients and median tumor size was 5 cm at the time of diagnosis. TNM stage distribution at presentation: T1 2%, T2 25%, T3 57%, T4 16%; N0 29%, N1 46%, N2 16%, N3 7%; M0 100%. pCR in breast; axilla; and both breast and axilla was observed in 19 of 44 patients (43.2%; 95% CI 28.3% - 59.0%); in 29 of 44 patients (65.9%; 95% CI 50.1% - 79.5%); and in 16 of 44 patients (36.4%; 95% CI 22.4% - 52.2%), respectively. No grade 4 or 5 toxicity occurred. The most frequent grade 3 toxicities were hand-foot syndrome (7%), neutropenia (4%), nausea/vomiting (2%), and bone pain (2%). Grade 2 cardiotoxicity was seen in 8% of patients and no grade 3 cardiotoxicity was observed. Conclusions: This neoadjuvant regimen was well tolerated and yielded a good pCR rate for this high risk group of patients.

No significant financial relationships to disclose.

Does delay of adjuvant chemotherapy affect the clinical outcome in patients with colon cancer?

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Background: Adjuvant chemotherapy (AC) in patients with stage III colon adenocarcinoma prevents recurrences and improves survival. Although most trials mandate initiation of AC within 8 weeks of resection, the impact of timing of AC is still not clear with few studies reporting conflicting results. We hypothesized that AC commenced within 60 days of resection would increase survival in patients with stage II and III colon cancer. Methods: Patients with newly diagnosed stage II or III colon adenocarcinoma who received fluoropyrimidine based AC in two centers (a private cancer center and a large community hospital) between 2000 and 2007 were included into analysis. Time to adjuvant chemotherapy (TTC), overall survival (OS), and relapse-free survival (RFS) were calculated from the surgery date. Patients were dichotomized into early- (group 1) and late-treatment (group 2) groups using the TTC of 60 days. The demographic, clinical, and laboratory characteristics of patients in two groups were compared using chi-square and t-test. Kaplan-Meier survival curves were constructed employing univariate log-rank test to assess the effects of demographic and clinical characteristics on OS. Then the impact of TTC on OS and RFS was analyzed using a Cox proportional hazard model incorporating the significant factors found in the univariate analysis. Results: 190 patients were eligible for the study (median age: 57 yrs [range 14–84]). 116 patients (61%) were female and 35 patients (18%) had stage II disease. Median TTC was 49 days (range 24–196) and median follow-up was 143 weeks (range 9–451). 134 patients (70%) received AC within 60 days of surgery (group 1) and 56 (30%) received after (group 2). The only difference between the two groups was the higher N stage in group 1. The treating hospital and the N stage were found to be the factors affecting the OS in univariate analysis. Five-year OS for group I was 75.2% as compared to 61.3% for group II (HR 2.11, CI: 1.00–4.45, p=0.049). Five-year RFS for group I was 65.7% as compared to 59.0% for group II (HR: 1.19, CI: 0.65–2.20, p=0.570). Conclusions: Delay of AC more than 60 days after resection is associated with inferior survival in stage II/III colon cancer.

No significant financial relationships to disclose.

Post-trabeculectomy choroidal detachment: not an adverse prognostic sign for either visual acuity or surgical success

PURPOSE

To report the incidence of choroidal detachment (CD) following trabeculectomy and to evaluate its effect on long-term surgical success and best-corrected visual acuity (BCVA).

METHODS

A total of 253 eyes of 198 subjects who underwent trabeculectomy between 1993 and 2003 with at least 1 year follow-up were reviewed retrospectively. Twenty-eight eyes of 28 subjects which developed CD postoperatively were classified as Group 1 and the remaining 225 eyes of 170 subjects as Group 2. The risk factors for the development of CD and the influence of CD on BCVA and on the success of trabeculectomy were analyzed and compared between the two groups.

RESULTS

In Group 1, preoperative BCVA was significantly lower and cup to disc ratio and the frequency of pseudoexfoliative glaucoma were higher with respect to the control group (p=0.009, p=0.01, p=0.02). The correlations between the development of CD and postoperative findings such as shallowing of the anterior chamber, hypotony, hypotonic maculopathy, hyphema, and fibrin reaction in the anterior chamber were statistically significant.CD was not associated with a significant reduction of BCVA. Intraocular pressures at postoperative first day, sixth month, and first year were lower in Group 1. The success of trabeculectomy and the average number of medications used were not significantly different between the two groups.

CONCLUSIONS

CD following trabeculectomy occurred in 11% of our patients. CD was not associated with either a significant drop in BCVA or an adverse influence on long-term IOP control.

Radial keratotomy for the optical rehabilitation of mild to moderate keratoconus: more than 5 years' experience

PURPOSE

To present the authors' long-term experience of radial keratotomy (RK) for the optical rehabilitation of patients with mild to moderate keratoconus--central corneal thickness of greater than 400 microm and without apical scarring.

METHODS

In this observational, noncomparative series of cases, all consecutive patients with mild or moderate keratoconus, treated by RK between 1990 and 2002, with at least 1 year follow-up were included. A total of 170 eyes of 96 patients were investigated. Mean follow-up was 42.08 +/- 28.14 months. Visual acuity, refraction, corneal curvature, central corneal thickness, and complications were evaluated.

RESULTS

In all of the control visits, mean uncorrected and best spectacle corrected visual acuities were better than preoperative values (p<0.0001). Preoperative myopic spherical refraction decreased significantly (p<0.0001), and remained relatively unchanged throughout the follow-up (p=0.43). A small but statistically significant decrease from baseline was ob-served in astigmatism (p=0.038), which almost disappeared 1 year after the surgery (p=0.47). The surgery produced a statistically significant flattening of the corneal curvature (p<0.0001). Central corneal thickness did not change significantly (p>0.05) in either control visit. In 33 eyes (19.4%), re-deepening of the incisions was required. In 3 eyes (1.8%) penetrating keratoplasty was performed, due to disease progression in 2 eyes (1.2%) and acute traumatic hydrops in 1 eye (0.6%). In 4 eyes (2.2%) microperforation, in 2 eyes (1.2%) macroperforation, in 1 eye (0.6%) infectious keratitis, and in 1 eye (0.6%) hyperopic shift occurred.

CONCLUSIONS

RK surgery was found to be a reasonable option for the rehabilitation of a selected group of keratoconus patients in the early or moderate stages.

CT-gesteuerte Resektion pulmonaler Metastasen

PURPOSE

To evaluate the feasibility and potential use of intraoperative computed tomography (IOP CT) as guidance for video-assisted thoracic surgery (VATS).

MATERIAL AND METHODS

Fifteen consecutive patients with peripheral intrapulmonary nodules underwent a thoracoscopy with IOP CT. Solitary lesions were known in 6/15 patients (40 %, group II) whereas 9/15 (60 %, group I) patients had multiple lesions (n >/= 2). IOP CT was performed with the mobile CT scanner Philips Tomoscan M. Radiologists intraoperatively placed percutaneous marks of lung lesions after unsuccessful VATS by use of a lung marker set (Somatex, Teltow, Germany). VATS was performed under general anaesthesia and with double lumen endotracheal intubation for single lung ventilation. Imaging quality and imaging of pulmonary nodules were rated.

RESULTS

IOP CT was evaluated as feasible combined with VATS. Thoracotomy was avoided in 5/15 patients where lesions could not be detected by VATS. A CT-guided biopsy was performed in two patients after an unsuccessful attempt of thoracoscopy. There were no documented side effects.

CONCLUSION

First clinical results suggest that a combination of VATS and IOP CT is feasible. Thus, the number of open thoracoscopies might be decreased. Intrapulmonary lesions not detectable with VATS could be marked under CT -- guidance intraoperatively and then resected by thoracoscopy.

Central corneal thickness and intraocular pressure relationship in eyes with and without previous LASIK: comparison of Goldmann applanation tonometer with pneumatonometer

PURPOSE

To investigate central corneal thickness (CCT) and intraocular pressure (IOP) relationship in eyes with and without previous corneal laser refractive surgery and to compare the estimates of two different tonometers-Goldmann applanation and pneumatonometer.

METHODS

The study population included 234 glaucoma suspects who were referred to the glaucoma clinic with cup/disc ratios greater than 0.4, asymmetric cupping, and/or IOP greater than 22 mmHg during routine eye examination. Of those, 84 had previous myopic laser-assisted in situ keratomileusis (LASIK) (Group 1) while 150 of them did not (Group 2). CCT was measured by using optical coherence tomography (OCT) and IOP with both Goldmann applanation tonometer (GAT) and pneumatonometer (PT). In both groups, the difference between IOP estimates of two different tonometers and the relationship between CCT and IOP were analyzed.

RESULTS

In eyes with previous LASIK, GAT measured IOP significantly lower than PT (mean difference of 3.8+/-1.9 mmHg, p<0.0001). In eyes with virgin corneas, IOP estimates of GAT or PT were not different from each other (19.9+/-2.8 versus 19.9+/-2.2 mmHg, respectively, p=0.81). In both groups, there was a significant positive correlation between CCT and IOP estimates of GAT(R=0.29, p=0.007 in eyes with LASIK and R=0.38, p<0.0001 in those without), while no similar relationship was present between CCT with those of PT (R=0.03, p=0.76 in eyes with LASIK and R=0.03, p=0.69 in those without).

CONCLUSIONS

In eyes with previous LASIK, GAT measured IOP significantly lower than PT. Because IOP estimates of PT were found to be independent from CCT in all of the study eyes, this device was considered to be a more reliable method of IOP estimation than GAT in eyes with and without previous LASIK.

Sentinel lymphonodectomy in gastrointestinal cancer--where are we now?

Up to now, no reliable methods for the pre- or intraoperative prediction of the nodal status are available in gastrointestinal cancer patients. Therefore, after the successful application of the sentinel lymph node concept in melanoma and breast cancer, ongoing research on this field is extended to gastrointestinal tumor entities. According to recent experiences, the most promising tumor entities are colon, gastric and anal cancer. First results with these patients indicate that the method could be a reliable predictor of the nodal status and, thus, may have important future implications for adjuvant therapy and the extent of surgery. The dye method for colon cancer and the combined method (dye and radiocolloid) for gastric cancer seem to be appropriate approaches, even when the general experience is still low. In rectal cancer, however, current experience failed yet to yield satisfying results. Up to now, anal cancer has not been a focus of publication, even when the concept seems to be very attractive for the evaluation of the inguinal lymph node status.

Endoscopic goniotomy with anterior chamber maintainer: surgical technique and one-year results

The surgical technique of endoscopic goniotomy (EG) using the anterior chamber maintainer (ACM) for congenital glaucoma is evaluated, and one-year follow-up data are presented. Endoscopic goniotomy was performed in 12 eyes of 7 patients. A double-port-special goniotomy knife mounted on the endoscope's probe inserted through the first incision and ACM through the second incision-EG technique was used in 6 eyes of 3 patients, while a three-port-knife, endoscope probe, and ACM inserted through separate incisions-technique was preferred in the remaining 6 eyes of 4 patients. EG of approximately 240 degrees could be done without major complications in all eyes. At the end of the average follow-up period of 14.2 +/- 9.7 months, the mean intraocular pressure was reduced from 38.3 +/- 6.9 mm Hg to 17.6 +/-, 2.8 mm Hg (P = 0.002), the average number of glaucoma medications from 2.1 +/- 0.3 to 0.3 +/- 0.5 (P = 0.001), and the mean cup/disk ratios from 0.84 +/- 0.11 to 0.79 +/- 0.14 (P = 0.014), while there was no statistically significant change in the average corneal diameter (P = 0.16). Therefore, endoscopic goniotomy with ACM was found to be an effective treatment modality for congenital glaucoma.

Capsular tension ring implantation after capsulorhexis in phacoemulsification of cataracts associated with pseudoexfoliation syndrome. Intraoperative complications and early postoperative findings

PURPOSE

To evaluate the effect of an endocapsular tension ring in preventing zonular complications during phacoemulsification of cataracts associated with pseudoexfoliation syndrome.

SETTING

Eye Clinic of Beyoğlu Education and Research Hospital, Istanbul, Turkey.

METHODS

A prospective randomized study comprised 78 eyes with cataract and pseudoexfoliation syndrome that were randomly divided into 2 groups. The age, sex, cataract density, iridodonesis, axial length, anterior chamber depth, best corrected visual acuity (BCVA), and intraocular pressure (IOP) were matched between groups. In 39 eyes, a capsular tension ring (CTR) was implanted after capsulorhexis and hydrodissection but before nucleus emulsification. Thirty-nine eyes that did not have a CTR implanted served as a control. The main outcome measures were the rates of intraoperative zonular separation and capsular fixation of a foldable intraocular lens (IOL). Posterior capsule rupture without zonular dialysis, vitreous loss, corneal edema, fibrin in the anterior chamber, BCVA, and IOP in the immediate postoperative period were also compared between the 2 groups.

RESULTS

Five eyes (12.8%) in the control group and no eye in the CTR group had intraoperative zonular separation (P =.02). Posterior capsule rupture without zonular separation occurred in 3 eyes (7.7%) in the control group and 2 (5.2%) in the CTR group. Capsular IOL fixation was achieved in 37 eyes (94.9%) in the CTR group and 31 eyes (74.3%) in the control group (P =.012). The difference in BCVA was not statistically significant between the 2 groups (P =.44); however, uncorrected visual acuity (UCVA) was significantly better in the CTR group (P =.026).

CONCLUSION

In cases of cataract associated with pseudoexfoliation syndrome, implanting a CTR before phacoemulsification of the nucleus reduced intraoperative zonular separation, increased the rate of capsular IOL fixation, and improved UCVA.

Odontogenic myxoma containing osteocement-like spheroid bodies: report of a case with an unusual histopathological feature

The odontogenic myxoma is a rare, benign, but locally invasive tumour of the jaws. Radiographically, it is a bone destroying lesion and has ill-defined borders. Histological characteristics are spindle and stellate-shaped tumour cells and a distinct myxomatous stroma. Bony islands that represent residual trabeculae are found scattered throughout the lesion. This report describes a case of odontogenic myxoma that shows diffusely dispersed osteocement-like spherular calcified bodies, unlike residual bone trabeculae, and discusses its differential diagnosis.

Influence of scan radius correction for ocular magnification and relationship between scan radius with retinal nerve fiber layer thickness measured by optical coherence tomography

PURPOSE

To investigate how optical coherence tomography (OCT) modifies the preset scan parameters to correct the errors resulting from ocular magnification, the influence of examiner's final correction of those already modified parameters on retinal nerve fiber layer (RNFL) thickness measurements, the induced change on RNFL thickness measurements and RNFL estimated integrals (RNFL(estimated integrals)) by adjusting the actual scan radius during RNFL examinations performed by OCT.

METHODS

Thirty-five healthy patients underwent an RNFL examination by OCT four times using different scan radii. The first scan was performed with the preset circular scan diameter of 3.46 mm; the actual scan diameter was different, however, because it was modified by the OCT instrument. The second, third, and fourth scans were generated after readjusting the already modified scan diameter by the examiner to 3.46, 3.20, and 3.60 mm. The relationship of axial length and refractive error with the actual scan radius (with ocular magnification calculated by OCT), with the influence of the examiner's final correction on RNFL thickness measurements, with the relationship between scan radius with RNFL thickness measurements, and with RNFL(estimated integrals) were investigated.

RESULTS

The actual scan diameter was found to be primarily determined by axial length (R = 0.97, P < 0.0001), but the influence of refractive error was small (R = -0.26, P = 0.067). Final correction of the actual scan radius by the examiner had a significant influence on RNFL thickness measurements (P = 0.025). RNFL thickness measurements obtained without correction of the actual scan radius for magnification were found to be inversely correlated with axial length (R = -0.54, P = 0.001), whereas no similar relationship was found when RNFL thickness measurements were obtained with correction (R = 0.21, P = 0.11). A reciprocal relationship between 1/scan radius with RNFL thickness measurements (they tended to be thinner as scan radii were increased) was found (R = 0.41, P = 0.169), but RNFL(estimated integrals) areas were found to be independent of the scan radius (P = 0.521).

CONCLUSION

To increase the accuracy of RNFL thickness measurements, it will be appropriate for the examiner to manually correct the actual scan parameters to the desired or preset ones after their automatic modification performed by the OCT instrument. Keeping the actual scan radius constant for repeated exams is also recommended because RNFL thickness measurements were found to depend on scan size. Alternatively, RNFL(estimated integrals) could be used because they were found to be independent of the scan size.

Posterior capsule opacification 3 years after implantation of an AcrySof and a MemoryLens in fellow eyes

PURPOSE

To compare the rates of lens epithelial cell (LEC) migration and posterior capsule opacification (PCO) 1 and 3 years after sutureless small incision phacoemulsification and in-the-bag implantation of 2 acrylic polymer intraocular lenses (IOLs)-the AcrySof and MemoryLens-in fellow eyes of patients.

SETTING

Eye Clinic, Beyoğlu Education and Research Hospital, Istanbul, Turkey.

METHODS

Fifty patients with no systemic or ocular problems that would interfere with postoperative visual acuity were included in this prospective study. Each patient had in-the-bag implantation of an AcrySof IOL in 1 eye and a MemoryLens in the fellow eye in a randomized fashion after uneventful phacoemulsification through a sutureless clear corneal incision.

RESULTS

At 1 year (n = 32 patients), there was no significant difference between fellow eyes in postoperative best corrected visual acuity (BCVA) and contrast sensitivity. In the MemoryLens group, 10 eyes (31.3%) had PCO and 9 (28.1%), LEC migration. In the AcrySof group, no eye had PCO and 2 eyes (6.3%) had LEC migration (P <.001). At 3 years (n = 21 patients), 1 eye (4.7%) in the AcrySof group had PCO and 3 eyes (14.4%) had LEC migration without PCO. In the MemoryLens group, 1 eye (4.7%) had a clear posterior capsule, 11 eyes (52.4%) had LEC migration, and 9 eyes (42.9%) had PCO (P <.001). A neodymium:YAG capsulotomy was required in 4 eyes (19.0%) in the MemoryLens group but no eye in the AcrySof group. At 3 years, BCVA was lower in the MemoryLens group than in the AcrySof group (P <.05).

CONCLUSION

The 3 year clinical data of fellow eyes indicate that the AcrySof IOL causes less PCO than the MemoryLens.