Bioequivalence study of two imatinib formulations after single-dose administration in healthy Korean male volunteers

Imatinib mesylate is effective for chronic myeloid leukaemia and gastrointestinal tumours. We aimed to evaluate the pharmacokinetics of a 200-mg imatinib tablet compared to 2×100-mg imatinib tablets in order to meet the regulatory requirements for marketing in Korea.An open-label, randomized, single-dose, 2-period, 2-treatment cross-over study was conducted in 28 healthy Korean male volunteers. Subjects were administered a 200-mg imatinib tablet and 2×100-mg imatinib tablets under a fasting state according to a randomly assigned order with a 2-week wash-out period. Serial blood samples were collected up to 72 h post-dose. The pharmacokinetic parameters were calculated using non-compartmental methods.A total of 28 subjects were enrolled and 23 subjects completed the study. There were no serious adverse events during the study. 23 mild to moderate adverse events were reported (11 events with 200-mg imatinib vs. 12 events with 2×100-mg imatinib) and subjects recovered without sequelae. The Cmax value was 922.8±318.8 μg/L at 3.15 h for 200-mg imatinib tablet, and 986.3±266.0 μg/L at 2.91 h for the 2×100-mg imatinib tablet. The AUClast of 200-mg and 2×100-mg tablets were 13 084.3±39.1 and 14 131.7±3 826.2 h · μg/L, respectively. The geometric mean ratios (90% confidence intervals) for Cmax and AUClast were 0.9121 (0.8188, 1.0161) and 0.9558 (0.8685, 1.0519), respectively.A newly developed 200-mg imatinib tablet was bioequivalent to 2×100-mg imatinib tablets in healthy Korean subjects. A single-dose of either of the 2 formulations was generally well tolerated.

Behavioral changes of zebrafish according to cisplatin-induced toxicity of the balance system

Background and objectives:

Zebrafish are commonly used as experimental animals in otolaryngology studies. However, the behavioral characteristics of these fish are not well known, especially those related to the vestibular system. The goal of this study was to evaluate behavioral changes in zebrafish due to toxicity in the balance system.

Materials and methods:

Zebrafish were exposed to 1000 μM cisplatin for 6 h. We, then, periodically monitored swimming depth, total swimming distance, peak swimming velocity, and mean swimming velocity of the fish for approximately 21 days.

Results:

Total swimming distance ( p < 0.0001), peak swimming velocity ( p = 0.0063), and mean swimming velocity ( p < 0.0001) in the cisplatin-administered group were significantly decreased when compared with control fish.

Conclusion:

Our findings demonstrate that cisplatin can alter the locomotion behavior of zebrafish.

Multi-valued logic gates based on ballistic transport in quantum point contacts

Multi-valued logic gates, which can handle quaternary numbers as inputs, are developed by exploiting the ballistic transport properties of quantum point contacts in series. The principle of a logic gate that finds the minimum of two quaternary number inputs is demonstrated. The device is scalable to allow multiple inputs, which makes it possible to find the minimum of multiple inputs in a single gate operation. Also, the principle of a half-adder for quaternary number inputs is demonstrated. First, an adder that adds up two quaternary numbers and outputs the sum of inputs is demonstrated. Second, a device to express the sum of the adder into two quaternary digits [Carry (first digit) and Sum (second digit)] is demonstrated. All the logic gates presented in this paper can in principle be extended to allow decimal number inputs with high quality QPCs.

Abstract S4-04: Overcoming resistance to PI3K inhibitors in PIK3CA mutant breast cancer using CDK4/6 inhibition: Results from a combinatorial drug screen

Various components of the phosphatidylinositol 3-kinase (PI3K) pathway are deregulated across a spectrum of human cancers. Notably, cancers with PIK3CA mutations, seen in roughly 30% of breast cancers, are amongst the most sensitive to PI3K inhibitors (PI3Ki) as single agents. Therefore, there have been great efforts to develop PI3K inhibitors specifically for these types of cancers, and many agents have already entered the clinic.

Although initial responses and prolonged stable disease have been observed, resistance frequently emerges. Moreover, there is a subset of PIK3CA mutated cancers that unexpectedly do not exhibit an initial response or disease stabilization upon exposure to PI3K inhibitors, despite presence of the mutation. These cancers are said to have de novo resistance to PI3K inhibition. To determine methods of overcoming resistance to PI3K inhibitors, we generated two models with acquired resistance to the p110a isoform specific inhibitor BYL-719 (BYL) using MDA-MB-453 (453) and T47D. We also established one model of resistance to the pan-PI3K inhibitor GDC-0941 using MCF7 cells. These lines were chosen because of their PIK3CA mutated status and sensitivity to PI3K inhibition. Each cell line was grown in increasing concentrations of PI3K inhibitor until the cells proliferated readily at a dose of drug that effectively reduced cell viability and inhibited pAKT in the sensitive parental cell lines. Interestingly, both BYL resistant cells (453R and T47DR) were cross resistant GDC and the MCF7R line was refractory to BYL.

To elucidate mechanisms to overcome resistance to PI3K inhibitors, we undertook a combinatorial drug screen, in which PI3K inhibitor resistant cells were treated with escalating doses of a panel of 45 targeted agents, both in the presence and absence of a fixed dose of PI3Ki, to determine which agents synergized effectively with PI3K inhibition in these resistant cells. We observed in each of the three PI3Ki resistant models a synergy between the CDK4/6 inhibitor LEE-011 and PI3K inhibition. We furthermore tested this combination of agents in a PIK3CA mutated breast cancer model with de novo resistance to PI3K inhibitors, CAL51, and again noted efficacy with the combination of GDC and LEE-011 while either agent on its own displayed minimal activity.

To determine whether addition of CDK 4/6 inhibition might be an effective addition to PI3Ki in the upfront setting in vivo, we injected each of the PIK3CA mutated lines MCF7, 453, and T47D into female nude mice and treated with vehicle, BYL, LEE-011, or the combination. We noted in each of the three models that the combination of agents, led to tumor regression that was more substantial than single agent treatment, and furthermore delayed the acquisition of resistance relative to single agent therapy. We furthermore tested GDC with LEE-011 singly and in combination in both MCF7 and CAL51 xenografts and again noted that the combination of agents led to tumor regression, whereas in these instances, single agent treatment did not.

We conclude that the combination of PI3K and CDK 4/6 inhibition may be an effective strategy for treating PIK3CA mutated breast cancer and deserves further study in the clinical setting.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S4-04.

Prediction of pseudoprogression in patients with glioblastomas using the initial and final area under the curves ratio derived from dynamic contrast-enhanced T1-weighted perfusion MR imaging

BACKGROUND AND PURPOSE

Dynamic contrast-enhanced T1-weighted perfusion MR imaging is much less susceptible to artifacts, and its high spatial resolution allows accurate characterization of the vascular microenvironment of the lesion. The purpose of this study was to test the predictive value of the initial and final area under the time signal-intensity curves ratio derived from dynamic contrast-enhanced perfusion MR imaging to differentiate pseudoprogression from early tumor progression in patients with glioblastomas.

MATERIALS AND METHODS

Seventy-nine consecutive patients who showed new or enlarged, contrast-enhancing lesions within the radiation field after concurrent chemoradiotherapy were assessed by use of conventional and dynamic contrast-enhanced perfusion MR imaging. The bimodal histogram parameters of the area under the time signal-intensity curves ratio, which included the mean area under the time signal-intensity curves ratio at a higher curve (mAUCRH), 3 cumulative histogram parameters (AUCR50, AUCR75, and AUCR90), and the area under the time signal-intensity curves ratio at mode (AUCRmode), were calculated and correlated with the final pathologic or clinical diagnosis. The best predictor for differentiation of pseudoprogression from early tumor progression was determined by receiver operating characteristic curve analyses.

RESULTS

Seventy-nine study patients were subsequently classified as having pseudoprogression (n=37, 46.8%) or early tumor progression (n=42, 53.2%). There were statistically significant differences of mAUCRH, AUCR50, AUCR75, AUCR90, and AUCRmode between the 2 groups (P < .0001, each). Receiver operating characteristic curve analyses showed the mAUCRH to be the best single predictor of pseudoprogression, with a sensitivity of 90.1% and a specificity of 82.9%. AUCR50 was found to be the most specific predictor of pseudoprogression, with a sensitivity of 87.2% and a specificity of 83.1%.

CONCLUSIONS

A bimodal histogram analysis of the area under the time signal-intensity curves ratio derived from dynamic contrast-enhanced perfusion MR imaging can be a potential, noninvasive imaging biomarker for monitoring early treatment response in patients with glioblastomas.

RNA∶DNA hybrids initiate quasi-palindrome-associated mutations in highly transcribed yeast DNA

RNase H enzymes promote genetic stability by degrading aberrant RNA∶DNA hybrids and by removing ribonucleotide monophosphates (rNMPs) that are present in duplex DNA. Here, we report that loss of RNase H2 in yeast is associated with mutations that extend identity between the arms of imperfect inverted repeats (quasi-palindromes or QPs), a mutation type generally attributed to a template switch during DNA synthesis. QP events were detected using frameshift-reversion assays and were only observed under conditions of high transcription. In striking contrast to transcription-associated short deletions that also are detected by these assays, QP events do not require Top1 activity. QP mutation rates are strongly affected by the direction of DNA replication and, in contrast to their elevation in the absence of RNase H2, are reduced when RNase H1 is additionally eliminated. Finally, transcription-associated QP events are limited by components of the nucleotide excision repair pathway and are promoted by translesion synthesis DNA polymerases. We suggest that QP mutations reflect either a transcription-associated perturbation of Okazaki-fragment processing, or the use of a nascent transcript to resume replication following a transcription-replication conflict.

Mutation rates are correlated with the level of gene expression in budding yeast, demonstrating a link between transcription and stability of the underlying DNA template. In the current work, we describe a novel type of transcription-associated mutation that converts imperfect inverted repeats (quasi-palindromes or QPs) to perfect inverted repeats. Using appropriate mutation reporters, we demonstrate that QP mutations are strongly affected by the direction of DNA replication and have distinctive genetic requirements. Most notably, rates of transcription-associated QP events are regulated by the RNase H class of enzymes, which are specialized to process the RNA component of RNA∶DNA hybrids. The source of the RNA∶DNA hybrids that initiate QP mutations is unclear, but could reflect transcripts that remain stably base-paired with the DNA template, or aberrant processing of the RNA primers normally used to initiate DNA synthesis. These studies further expand the diverse ways that transcription affects the mutation landscape, and establish a novel way that RNA∶DNA hybrids can contribute to genetic instability. The high conservation of basic DNA-related metabolic processes suggests that results in yeast will be broadly applicable in higher eukaryotes.

Differential function of natural killer cells in the liver graft perfusate of Korean population

BACKGROUND

Liver perfusate (LP) lymphocytes show unique subsets compared with peripheral blood (PB) lymphocytes. LP natural killer (NK) and NKT cells may display unique cytotoxicity and cytokine production, thus leading to distinct roles in liver transplantation. In this study, we sought to evaluate the functions of graft perfusate NK and NKT cells in clinical liver transplantation.

METHODS

The living donor right lobe graft was initially washed with 1 L of histidine-tryptophan-ketoglutarate solution to collect the perfusate. We also collected donor PB. Lymphocytes separated by the Ficoll-Hypaque density gradient method underwent immunophenotyping using multicolor flow cytometry. To assess cytokine secretion, we performed the enzyme-linked immunosorbent assay.

RESULTS

There were more NK and NKT cells in LP confirming previous reports. In particular, CD56(bright)CD16(low) NK cells accounted for approximately 50% of total NK cells compared with 5% to 10% among PB NK cells. In response to cytokine stimulation LP NK cells produce tumor necrosis factor-α at different levels and less interleukin-10 compared with PB NK cells. The major source of interferon-γ production upon stimulation with liver caner cells were CD56(dim) NK cells and CD56(-)CD3(-) cells rather than NKT or T cells. Unlike PB NK cells, LP CD56(bright)CD16(low) NK cells along with CD56(dim)CD16(high) NK cells and NKT cells were efficient killers against Korean liver cancer cells.

CONCLUSION

LP NK and NKT cells showed unique functions in cytotoxicity and cytokine production.

Mitochondrial modulation decreases the bortezomib-resistance in multiple myeloma cells

Multiple myeloma (MM) is an incurable hematological malignancy that causes most patients to eventually relapse and die from their disease. The 20S proteasome inhibitor bortezomib has emerged as an effective drug for MM treatment; however, intrinsic and acquired resistance to bortezomib has already been observed in MM patients. We evaluated the involvement of mitochondria in resistance to bortezomib-induced cell death in two different MM cell lines (bortezomib-resistant KMS20 cells and bortezomib-sensitive KMS28BM cells). Indices of mitochondrial function, including membrane potential, oxygen consumption rate and adenosine-5'-triphosphate and mitochondrial Ca(2+) concentrations, were positively correlated with drug resistance of KMS cell lines. Mitochondrial genes including CYPD, SOD2 and MCU were differentially expressed in KMS cells. Thus, changes in the expression of these genes lead to changes in mitochondrial activity and in bortezomib susceptibility or resistance, and their combined effect contributes to differential sensitivity or resistance of MM cells to bortezomib. In support of this finding, coadministration of bortezomib and 2-methoxyestradiol, a SOD inhibitor, rendered KMS20 cells sensitive to apoptosis. Our results provide new insight into therapeutic modalities for MM patients. Studying mitochondrial activity and specific mitochondrial gene expression in fresh MM specimens might help predict resistance to proapoptotic chemotherapies and inform clinical decision-making.

Histogram analysis of intravoxel incoherent motion for differentiating recurrent tumor from treatment effect in patients with glioblastoma: initial clinical experience

BACKGROUND AND PURPOSE

Intravoxel incoherent motion can simultaneously measure diffusion and perfusion characteristics. Our aim was to determine whether the perfusion and diffusion parameters derived from intravoxel incoherent motion could act as imaging biomarkers for distinguishing recurrent tumor from treatment effect in patients with glioblastoma.

MATERIALS AND METHODS

Fifty-one patients with pathologically confirmed recurrent tumor (n = 31) or treatment effect (n = 20) were assessed by means of intravoxel incoherent motion MR imaging. The histogram cutoffs of the 90th percentiles for perfusion and normalized CBV and the 10th percentiles for diffusion and ADC were calculated and correlated with the final pathology results. A leave-one-out cross-validation was used to evaluate the diagnostic performance of our classifiers.

RESULTS

The mean 90th percentile for perfusion was significantly higher in the recurrent tumor group (0.084 ± 0.020) than in the treatment effect group (0.040 ± 0.010) (P < .001). The 90th percentile for perfusion provided a smaller number of patients within an overlap zone in which misclassifications can occur, compared with the 90th percentile for normalized CBV. The mean 10th percentile for diffusion was significantly lower in the recurrent tumor group than in the treatment effect group (P = .006). Receiver operating characteristic curve analyses showed the 90th percentile for perfusion to be a significant predictor for differentiation, with a sensitivity of 87.1% and a specificity of 95.0%. There was a significant positive correlation between the 90th percentiles for perfusion and normalized CBV (r = 0.674; P < .001).

CONCLUSIONS

A histogram analysis of intravoxel incoherent motion parameters can be used as a noninvasive imaging biomarker for differentiating recurrent tumor from treatment effect in patients with glioblastoma.

Anemia increases the risk of renal cortical and medullary hypoxia during cardiopulmonary bypass

Introduction:

Anemia is an independent predictor of acute kidney injury (AKI) following cardiopulmonary bypass (CPB), possibly due to inadequate renal oxygen delivery. The objective of this study was to investigate the effects of CPB and anemia on tissue oxygen tension (pO2) and blood flow in the renal cortex and medulla.

Methods:

Rats (n=6/group) underwent 1hr of normothermic cardiopulmonary bypass (CPB), with target hemoglobin concentrations (Hb) of 10g/dL (CPB) or 6.5g/dL (anemia-CPB). Renal blood flow (RBF) and tissue PO2 were measured before, during and after 1hr of CPB. To confirm the observed differences in renal cortical and medullary PO2, HIF-1α (ODD) luciferase mice were exposed to 8% O2 (hypoxia) and HIF-1α dependent luminescence was measured in the renal cortex and medulla (n=5).

Results:

Renal tissue PO2 values decreased initially and returned towards baseline, however, values at the end of CPB. Anemia-CPB resulted in a significant increase in both renal cortical and medullary blood flow, PO2 remained significantly reduced throughout anemia-CPB. Renal medullary HIF-1α-dependent luminescence confirmed a greater degree of hypoxia in the renal medulla.

Discussion:

During CPB, renal O2 delivery was transiently jeopardized, but recovered after 1hr. Anemia-CPB resulted in a dramatic and sustained reduction in renal cortical and medullary PO2, which suggests an increased risk of renal hypoxic injury with anemia.

Conclusion:

The clear difference in the degree of hypoxia in the renal cortex and medulla may be useful in understanding the progress of medullary hypoxia during CPB with anemia and the potential development of AKI. Further studies should aim at identifying early markers of medullary hypoxia and potential agents that may decrease the work and O2 consumption in the renal medulla to reduce the risk of hypoxic damage during CPB and anemia.

Charge frustration in a triangular triple quantum dot

We experimentally investigate the charge (isospin) frustration induced by a geometrical symmetry in a triangular triple quantum dot. We observe the ground-state charge configurations of sixfold degeneracy, the manifestation of the frustration. The frustration results in omnidirectional charge transport, and it is accompanied by nearby nontrivial triple degenerate states in the charge stability diagram. The findings agree with a capacitive interaction model. We also observe unusual transport by the frustration, which might be related to elastic cotunneling and the interference of trajectories through the dot. This work demonstrates a unique way of studying geometrical frustration in a controllable way.

Two distinct mechanisms of Topoisomerase 1-dependent mutagenesis in yeast

Topoisomerase 1 (Top1) resolves transcription-associated supercoils by generating transient single-strand breaks in DNA. Top1 activity in yeast is a major source of transcription-associated mutagenesis, generating a distinctive mutation signature characterized by deletions in short, tandem repeats. A similar signature is associated with the persistence of ribonucleoside monophosphates (rNMPs) in DNA, and it also depends on Top1 activity. There is only partial overlap, however, between Top1-dependent deletion hotspots identified in highly transcribed DNA and those associated with rNMPs, suggesting the existence of both rNMP-dependent and rNMP-independent events. Here, we present genetic studies confirming that there are two distinct types of hotspots. Data suggest a novel model in which rNMP-dependent hotspots are generated by sequential Top1 reactions and are consistent with rNMP-independent hotspots reflecting processing of a trapped Top1 cleavage complex.

Abstract OT1-1-01: A phase II study of neoadjuvant epirubicin/cyclophosphamide (EC) followed by weekly nanoparticle albumin-bound paclitaxel with or without trastuzumab for node-positive breast cancer

Background: Paclitaxel is considered standard treatment for metastatic breast cancer (MBC) and is often used as adjuvant and neoadjuvant chemotherapy for patients with early-stage disease. Conventional paclitaxel requires solvents such as polyoxyethylated castor oil; however, such solvents are associated with toxicity including peripheral neuropathy and hypersensitivity reaction. Moreover, the use of the drug requires special tubing and in-line filters. Therefore, nanoparticle albumin-bound paclitaxel (nab-PTX) requiring no solvent has been developed. Nab-PTX was effective in patients with MBC and as a neoadjuvant therapy. A comparison between weekly and triweekly nab-PTX suggested that weekly nab-PTX was superior in progression-free survival.

Trial design: This is a phase II trial to evaluate the efficacy and toxicity of neoadjuvant epirubicin/cyclophosphamide (EC) (epirubicin/cyclophosphamide) followed by weekly nab-PTX with or without trastuzumab for node-positive breast cancer. Patients receive four cycles of epirubicin (90 mg/m2) and cyclophosphamide (600 mg/m2) every 3 weeks, followed by four cycles of nab-PTX (125 mg/m2) on days 1, 8 and 15 in a 28-day cycle. Fifteen cycles of trastuzumab (2 mg/kg, loading 4 mg/kg) are added to the nab-PTX regimen in HER2-positive patients every week.

Eligibility criteria: Patients with histologically diagnosed invasive breast cancer based on a core needle biopsy of the T1-4 N1-3 without previous operation or chemotherapy are included in this trial. Eligible patients are aged between 20 years and 70 years with a performance status of 0 to 2 and adequate organ functions.

Specific aims: The primary endpoint is the pathologic complete response (pCR) rate in the breast and axilla, and the secondary endpoints are the breast conserving rate, toxicities, feasibility and overall survival.

Statistical methods: The sample size was calculated using the Simon method, with a type I error of 10% and a study power of 80%. 1. HER2-negative patients

The expected rate of pCR was 25% and the required number of patients was estimated to be 33. 2. HER2-positive patients

The expected rate of pCR was 50%, and the required number of patients was estimated to be 21.

Present and target accrual: Patient accrual within two medical centers started in April 2011 with 20 patients being on study to date (2012, June 12). A total of 56 patients (22 are HER2-positive and 34 are HER2-negative) are planned to be enrolled in the trial.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT1-1-01.

NF-κB: an essential transcription factor in psoriasis

Nuclear factor kappa B (NF-κB) is a protein transcription factor that orchestrates inflammation and other complex biological processes. It is a key regulatory element in a variety of immune and inflammatory pathways, in cellular proliferation and differentiation and in apoptosis. Therefore NF-κB is a crucial mediator involved in the pathogenesis of psoriasis. Psoriasis, an inflammatory dermatosis, is marked by elevated levels of active, phosphorylated NF-κB. Genomic studies have also linked psoriasis with mediators in the NF-κB pathway. NF-κB has been hypothesized to connect the altered keratinocyte and immune cell behavior that characterizes the psoriatic milieu. Several anti-psoriatic therapies, including tumor necrosis factor-α blockers and glucocorticoids, reduce active NF-κB levels and related down-stream elements, and other biologics currently in development, including interleukin-17 blockers, may also target this pathway. Compounds that specifically target NF-κB signaling may be developed as novel therapeutics for chronic inflammatory disorders including psoriasis. However, chronic NF-κB inhibition could also result in immunodeficiencies. Therefore, a delicate balance must be found that maximizes therapeutic potential while limiting harmful effects, and may be achieved through several possible approaches, including localized therapy, selective inhibition of NF-κB signaling in pathologic cells, incomplete pathway inhibition or short treatment durations.

Regional cerebellar volume reflects static balance in elite female short-track speed skaters

The cerebellum plays a critical role in balance control. Particularly, elite short-track speed skaters require fine postural control to keep a postural balance during high velocity movement across smooth ice. We investigated whether skating proficiency and gender have an effect on the volume of cerebellar subregions and static balance, using 3-dimensional magnetic resonance imaging volumetry. In addition, we further analyzed which subregions of the cerebellum correlates with the balance. The volumes of cerebellar subregions and static balance index were compared among 12 male and 11 female elite short-track speed skaters, and 11 male and 14 female healthy matched subjects. We found significant main effects of skating proficiency and gender on the volume of vermian lobule VI-VII (declive, folium, and tuber), short-track speed skaters having greater volume than control and women revealing greater volume than men. Especially, in female athletic group, the volume of vermian lobule VI-VII significantly correlates with left static balance. In addition, men showed larger skating proficiency-related differences than women in the performance of static balance. The correlation between the volume of this region and static balance in female short-track speed skaters suggests that this region would plays a critical role in balance.

Lacrimal drainage obstruction in gastric cancer patients receiving S-1 chemotherapy

BACKGROUND

This study was conducted to determine the incidence and clinical characteristics of lacrimal drainage obstruction (LDO) in patients receiving S-1 chemotherapy.

PATIENTS AND METHODS

Consecutive 170 patients with gastric cancer who underwent curative surgery and received adjuvant S-1 chemotherapy were enrolled. S-1 was administered orally (40 mg/m2 b.i.d. on days 1-28 every 6 weeks) for 1 year. Ophthalmologic examinations were carried out on patients complaining of epiphora.

RESULTS

Thirty-one patients (18%) developed epiphora. Among 31 patients, 25 underwent ophthalmologic examinations and 22 (88%) were diagnosed with LDO. The median time to the onset of LDO was 2.9 months. The most common site of obstruction was the nasolacrimal duct [86% (19/22)]; punctal [23% (5/22)] and canalicular obstruction [14% (3/22)] were also noted. In multivariate analysis, total gastrectomy [versus partial gastrectomy: hazard ratio (HR), 2.9; P=0.014] and creatinine clearance<50 ml/min (versus ≥50 ml/min: HR, 2.9; P=0.038) were independent risk factors for the development of LDO.

CONCLUSION

Considering the high incidence of LDO in patients receiving S-1 chemotherapy, oncologists should be alert to epiphora and cooperate with ophthalmologists in the early stages to improve the quality of life of patients and avoid more complicated ophthalmologic procedures.