BRAF mutation is a powerful prognostic factor in advanced and recurrent colorectal cancer.

BACKGROUND: Activating mutation of KRAS and BRAF are focused on as potential prognostic and predictive biomarkers in patients with colorectal cancer (CRC) treated with anti-EGFR therapies. This study investigated the clinicopathological features and prognostic impact of KRAS/BRAF mutation in advanced and recurrent CRC patients. METHOD: Patients with advanced and recurrent CRC treated with systemic chemotherapy (n=229) were analysed for KRAS/BRAF genotypes by cycleave PCR. Prognostic factors associated with survival were identified by univariate and multivariate analyses using the Cox proportional hazards model. RESULTS: KRAS and BRAF mutations were present in 34.5% and 6.5% of patients, respectively. BRAF mutated tumours were more likely to develop on the right of the colon, and to be of the poorly differentiated adenocarcinoma or mucinous carcinoma, and peritoneal metastasis. The median overall survival (OS) for BRAF mutation-positive and KRAS 13 mutation-positive patients was 11.0 and 27.7 months, respectively, which was significantly worse than that for patients with wild-type (wt) KRAS and BRAF (40.6 months) (BRAF; HR=4.25, P<0.001, KRAS13; HR=2.03, P=0.024). After adjustment for significant features by multivariate Cox regression analysis, BRAF mutation was associated with poor OS (HR=4.23, P=0.019). CONCLUSION: Presence of mutated BRAF is one of the most powerful prognostic factors for advanced and recurrent CRC. The KRAS13 mutation showed a trend towards poor OS in patients with advanced and recurrent CRC.

Retinal concentration and protective effect against retinal ischemia of nilvadipine in rats.

PURPOSE: Several calcium entry blockers have neuroprotective effects on cellular damage in the brain induced by ischemia. The purpose of this study was to determine whether nilvadipine (NID) crosses the blood-retinal barrier, and if so, whether it can then protect the photoreceptors against retinal ischemia-reperfusion injury. METHODS: Rats received an intramuscular injection of 1 mg/kg of NID and nifedipine (NIF), and the retinal and serum concentrations were measured. Ischemia was induced by raising the intraocular pressure for 45 minutes. Twenty-four hours after the reperfusion, the number of TUNEL positive cells and retinal ganglion cells (RGCs) were counted, and the thickness of the retina was measured. RESULTS: After 60 minutes, the concentration of NID, but not NIF, was higher in retina than in the serum. The number of TUNEL-positive cells was fewer and the reduction in the number of RGCs and the thickness of retina was less in the eyes that had received NID than controls. CONCLUSIONS: The findings show that NID has high permeability to retina compared with NIF, which has less fat solubility than NID, and neuroprotective effect to retinal cells. NID might be useful for the treatment of glaucoma or other retinal diseases that have some relation to apoptosis.

Use of autologous plasmin during vitrectomy for diabetic maculopathy.

PURPOSE: To evaluate the efficacy of autologous plasmin enzyme as an adjunct to vitrectomy in diabetic macular edema. METHODS: Plasmin derived from autologous blood was injected intravitreally into seven eyes 15 min before vitreous surgery. The development and progression of a posterior vitreous detachment (PVD) was followed, and the time required for vitreous removal was measured. Both pre- and postoperative visual acuities and optical coherence tomography (OCT)-determined macular thickness were measured. RESULTS: In the seven eyes in which plasmin was used, a PVD developed approximately 5 min after the injection and was confirmed to extend to the far periphery. In all cases, the removal of the vitreous was completed in a shorter time and no complications were observed. A restoration of the shape of the macula was observed in all cases. The visual acuity improved by two or more lines in four eyes, and remained unchanged in the remaining three eyes. CONCLUSIONS: Autologous plasmin alone will create a full PVD, and eliminates the need for a mechanical creation of a PVD. Thus, plasmin is a safe and effective adjunct to vitreous surgery for the treatment of diabetic maculopathy.

Efficacy of autologous plasmin for idiopathic macular hole surgery.

PURPOSE: To determine whether a single intravitreal injection of autologous plasmin or a combination of plasmin and intraocular gas without peeling the internal limiting membrane (ILM) will close idiopathic macular holes. METHODS: Eight eyes of seven patients with an idiopathic macular hole were studied. The degree of posterior vitreous detachment (PVD), vitreal liquefaction, closure of the macular hole, visual acuity, and complications following intravitreal plasmin or plasmin with gas were investigated. The removed ILM was examined by electron microscopy. RESULTS: A PVD was created in seven out of eight eyes exposed to plasmin or plasmin with gas, however, the macular hole was not closed by either. Closure occurred in two eyes using conventional vitrectomy after the plasmin with gas injection, but peeling the ILM was required in the remaining six eyes. Vitreal fibers and glial cells were not observed on the vitreal surface of the extracted ILM. CONCLUSIONS: A PVD was created safely and reliably although closure of the macular hole did not occur with either plasmin or with plasmin and gas injection. However, vitreous surgery became easier, and it required a shorter time to close the macular hole with intravitreal plasmin.

Protection of retinal ganglion cells from ischemia-reperfusion injury by electrically applied Hsp27.

PURPOSE: To determine whether the Hsp27 protein can rescue retinal ganglion cells (RGCs) of rats from ischemia-reperfusion injury. METHODS: Retinal ischemia was induced in rats by clamping the ophthalmic artery within the dural sheath of the optic nerve. Immediately after removing the clamp and beginning the reperfusion, Hsp27 protein solution was injected into the vitreous, and electroporation was applied. To determine whether Hsp27 entered the RGCs, anti-Hsp27 immunohistochemistry was performed. The retinal damage was evaluated by counting the number of RGCs retrogradely labeled by 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine percholorate (diI) injected into the superior colliculus, and also by comparing the ratio of TUNEL-positive to all RGCs in the RGC layer. RESULTS: Electroporation successfully delivered Hsp27 protein into RGCs. In the Hsp27 electroinjected group, the number of RGCs 7 days after ischemia-reperfusion was significantly higher than in the control groups. The ratio of TUNEL-positive cells to all RGCs was lower in the group electroinjected with Hsp27 protein. CONCLUSIONS: Electroporation of Hsp27 protein into RGCs increased the resistance of the RGCs to the apoptosis induced by ischemia-reperfusion injury.

[Follow-up studies of optic neuritis with lymphocytic adenohypophysitis].

BACKGROUND: We report a 38-year-old female suffering from bilateral optic neuritis with lymphocytic adenohypophysitis. CASE: The initial symptom of the 38-year-old-female was diabetes insipidus. Magnetic resonance imaging showed swollen pituitary stalk and disappearance of the T1 shortening of the neurohypophysis. Immunological tests showed that the serum anterior pituitary antibody was positive. These findings suggested lymphocystic adenohypophysitis. Bilateral optic neuritis also occurred and the pattern visual evoked cortical potential (VECP) demonstrated increased P100 peak latency and reduction of amplitude. After steroid pulse therapy, the visual acuity and field improved and the pattern VECP became normal. Temporal hemianopia was not noted. CONCLUSION: A direct infiltration of the inflammatory change in the pituitary gland or some autoimmune problem was considered as a cause of the optic neuritis. In contrast to the VECPs of multiple sclerosis patients, the prolonged peak latency of pattern VECPs of this case were shortened in accordance with the recovery of visual acuity.

Protective effect of docosahexaenoic acid against retinal ischemic injury: an electroretinographic study.

PURPOSE: To determine whether docosahexaenoic acid (DHA) can reduce the retinal damage induced by transient retinal ischemia. METHODS: Retinal ischemia was induced by increasing intraocular pressure (IOP). Retinal circulation was restored by lowering IOP. An intraperitoneal injection of 1,000 mg/kg of DHA-ester (DHA-E) was given 5 h before the ischemia. Electroretinograms were recorded just before the ischemia and at 60-min intervals up to 4 h after circulation was restored. RESULTS: The ratio of the amplitudes after the ischemia to that just before ischemia was significantly higher in eyes administered DHA-E than in controls at each time point (p < 0.01). CONCLUSION: DHA-E is effective in protecting the retina against transient retinal ischemia.

Sclerostomy with an Erbium YAG Laser. The Relationship with Pulse Energy.

Purpose: To investigate the optimal pulse energy to do sclerostomy with an erbium YAG laser.Materials and Methods: The experiments were performed in enucleated porcine eyes. We changed pulse energy and examined the effects on surrounding tissue.Results: With the increase of pulse energy, the effects of the laser extended to the area surrounding the laser probe. At the threshold energy for doing full-thickness sclerostomy, the total energy was significantly higher than with higher pulse energy. And with pulse energy higher than 2 mJ, the total energy did not show any significant change. Histopathologically, the damaged area around sclerostomy became larger with the increase of pulse energy.Conclusion: The optimal energy to do full-thickness sclerostomy with this system seemed to be 2 mJ.

Light and Electron Microscopic Study of the Retina in a Patient with Congenital Glaucoma.

Purpose: The morphological observation of the human retinal changes caused by severely elevated intraocular pressure (IOP) in congenital glaucoma.Method: Light and electron microscopy.Subjects: One eye of a 15-year-old boy diagnosed as having congenital glaucoma was obtained after he had suffered from severe visual disturbance and ocular pain because of extensive elevated IOP, corneal leucoma, and exophthalmos.Results: Ganglion cells and nerve fibers in the inner layer were lost and replaced by Müller cell processes. The cellular elements in the outer layer were regularly arranged, but these cytoplasmic organelles were not very well developed. Most of the cellular elements of the whole retina contained many dense bodies. The retinal capillaries in the nerve fiber layer were lost or severly damaged, but some of these in the inner plexiform layer were intact. In the retinal arteries and veins marked thickening of the adventitial tissues was observed. These tissues consisted of remarkably increased and irregularly arranged collagen fibers, and a few elastic fibers scattered in some parts.Conclusion: It appeared that the pathological changes in the inner layer of the retina were caused by ischemia. The retinal vascular abnormality was thought to be the result of protective reaction against the severly elevated IOP.

Lymphocytic infundibulo-neurohypophysitis associated with recurrent optic neuritis.

A 38-year-old woman presented with diabetes insipidus. The T1-weighted images showed a loss of the hyperintense signal of the posterior pituitary and thickening of the pituitary stalk. DDAVP was started with the diagnosis of lymphocytic infundibulo-neurohypophysitis (LINH). Three months later, she complained of right visual acuity loss. MRI revealed right optic nerve swelling, compatible with the diagnosis of the retrobulbar optic neuritis. She had two other such episodes in the next 3 months. She developed a transient oculomotor and abducens nerve palsies as well. Each time the symptoms disappeared with corticosteroid therapy. The pituitary stalk became normal in size 6 months later. LINH and recurrent optic neuritis occurred in a short duration. Accordingly, a common causative background is suspected. Since the auto-immune process has been hypothesized as a cause of optic neuritis, our case may present further clinical evidence to support the hypothesis of an auto-immune mechanism for LINH.

Facilitatory and neurotoxic effects of intravitreal ornithine on the electroretinographic responses of albino rats.

The effect of an intravitreal injection of ornithine on the retina of rats was studied electroretinographically. Rats were injected intravitreally with 5 microl of 0.02, 0.25 and 0.5 M ornithine. Electroretinograms (ERGs) were recorded before, and 1, 3 and 9 days after the injection. High doses of ornithine (0.5 M) reduced while low doses (0.02 M) enhanced the ERG amplitudes. The implicit time of the a-wave was delayed at all concentrations after ornithine injection, which suggests that implicit times may be a more sensitive parameter of the ornithine effect. There were significant changes in the stimulus intensity necessary to obtain the one half of the maximum amplitude of the b-wave that may have been caused by damage of the photoreceptors and retinal pigment epithelium cells by ornithine. We conclude that the effect of ornithine on retinal function is dose dependent and can either enhance or depress the ERG amplitudes.

Comparison of visual evoked potentials in patients with psychogenic visual disturbance and malingering.

PURPOSE: To verify the efficiency and objectivity of the pattern visual evoked potential (VEP) for organic disorders of the cortical visual system. METHODS: This retrospective study evaluated VEP in 19 patients diagnosed with psychogenic visual disturbance, 7 patients with malingering, and 37 age-matched normal volunteers. Transient (3 reversals per second) and steady-state (12 reversals per second) pattern VEPs for check sizes 15' and 30', with a contrast of 80%, were recorded. RESULTS: The amplitudes of both transient and steady-state pattern VEPs were significantly increased in patients with psychogenic visual disturbance, while patients with malingering had significantly lower amplitudes. P100 peak latency was prolonged in both groups of patients. CONCLUSION: Monitoring of patients' fixation on the stimulus showed those with psychogenic visual disturbance fixated well on the stimulus, while those with malingering did not. This finding produced a VEP amplitude reduction in patients with malingering. The reason for the VEP amplitude in patients with psychogenic visual disturbance is unclear.

Protective effects of dietary docosahexaenoic acid against kainate-induced retinal degeneration in rats.

PURPOSE: To investigate the role played by docosahexaenoic acid (DHA) in the retina, and more specifically, its ability to protect the retina from kainic acid (KA)-induced retinal damage. METHODS: Three-week-old female Wistar rats were used. DHA (1000 mg/kg per day) was fed to the rats for 7, 14, and 28 days, and the concentrations of DHA and arachidonic acid (AA) in the retina and serum were measured. In another group of rats, the right eyes were injected intravitreally with 3.12 nanomoles KA after DHA supplementation for 14 days. Electroretinograms (ERGs) elicited by different stimulus intensities were recorded before and on days 1, 7, and 14 after the KA injection. The amplitudes and implicit times of the a- and b-waves were compared. The number of cells in the ganglion cell layer (GCL) and inner nuclear layer (INL) were compared by histopathologic examination. RESULTS: The concentration of DHA in the serum and retina increased after DHA supplementation. The concentration of AA in serum decreased with DHA supplementation, but the concentration of AA in retina did not show any significant change. The b-waves of the ERGs recorded after KA injection were significantly attenuated in both groups of rats. However, the attenuation was significantly less in the DHA-supplemented rats than in gum arabic-supplemented control rats. The numbers of cells in the INL and GCL were significantly higher in DHA-supplemented rats. CONCLUSIONS: These results indicate that DHA supplementation can partially counteract KA neurotoxicity in the rat retina. DHA may play a role in modulating neuronal excitability by reducing KA-induced responses in the retina.

Comparative studies on pattern VECP between patients with ischemic optic neuropathy and optic neuritis.

PURPOSE: To evaluate whether and how VECPs are useful in differentiating ION from ON. METHODS: We retrospectively studied 27 patients with non-arteritic ION and 69 patients with ON using pattern visually evoked cortical potentials (PVECPs) to 3 rev/sec stimulation (transient) and 12 rev/sec stimulation (steady-state). RESULTS: In patients with ION, non-recordable responses were found in 25% of those with transient VECP and in 74% of those with steady-state VECP. In ON patients, non-recordable responses were found in 34% of those with transient VECP and in 64% of those with steady-state VECP. The average peak latency of P100 component in those with ION was significantly shorter than in those with ON. The amplitude ratio (affected eye/fellow eye) of steady-state VECP was significantly higher in those with ION than in those with ON. The amplitude ratio of P100 showed no significant differences between groups. CONCLUSION: The P100 peak latency of transient VECPs and the amplitude of steady-state VECPs have the potential to differentiate between ION and ON.

[Sclerostomy with an erbium YAG laser--the relationship with pulse energy].

PURPOSE: To investigate the optimal pulse energy to do sclerostomy with an erbium YAG laser. MATERIALS AND METHODS: The experiments were performed in enucleated porcine eyes. We changed pulse energy and examined the effects on surrounding tissue. RESULTS: With the increase of pulse energy, the effects of the laser extended to the area surrounding the laser probe. At the threshold energy for doing full-thickness sclerostomy, the total energy was significantly higher than with higher pulse energy. And with pulse energy higher than 2 mJ, the total energy did not show any significant change. Histopathologically, the damaged area around sclerostomy became larger with the increase of pulse energy. CONCLUSION: The optimal energy to do full-thickness sclerostomy with this system seemed to be 2 mJ.

[Light and electron microscopic study of the retina in a patient with congenital glaucoma].

PURPOSE: The morphological observation of the human retinal changes caused by severely elevated intraocular pressure (IOP) in congenital glaucoma. METHOD: Light and electron microscopy. SUBJECTS: One eye of a 15-year-old boy diagnosed as having congenital glaucoma was obtained after he had suffered from severe visual disturbance and ocular pain because of extensive elevated IOP, corneal leukoma, and exophthalmos. RESULTS: Ganglion cells and nerve fibers in the inner layer were lost and replaced by Müller cell processes. The cellular elements in the outer layer were regularly arranged, but these cytoplasmic organelles were not very well developed. Most of the cellular elements of the whole retina contained many dense bodies. The retinal capillaries in the nerve fiber layer were lost or severely damaged, but some of these in the inner plexiform layer were intact. In the retinal arteries and veins marked thickening of the adventitial tissues was observed. These tissues consisted of remarkably increased and irregularly arranged collagen fibers, and a few elastic fibers scattered in some parts. CONCLUSION: It appeared that the pathological changes in the inner layer of the retina were caused by ischemia. The retinal vascular abnormality was thought to be the result of protective reaction against the severely elevated IOP.

Pattern visual evoked cortical potentials in patients with toxic optic neuropathy caused by toluene abuse.

PURPOSE: Electrophysiological evaluation of the visual function of patients with toxic neuropathy caused by toluene abuse. METHODS: Fifteen patients (mean age 25.6 years, eight men and seven women) were diagnosed with bilateral optic neuropathy. Pattern visual evoked cortical potentials (PVECPs) and clinical symptoms were investigated. RESULTS: Visual acuities at the initial visit were less than 0.1 in 5 cases and 0.1-1.0 in 10 cases. PVECPs were followed up in the 15 cases. At the first recording, PVECPs were nonrecordable in both eyes of 11 cases, the P100 peak latency was prolonged in both eyes of 3 cases, and only 1 case showed a normal P100 peak latency. After treatment, visual acuities improved more than 2 lines in 6 cases, 3 of whom showed normal P100 peak latency in the PVECPs. Visual prognosis and PVECP changes were identical in both eyes of all patients. CONCLUSIONS: In patients with toluene optic neuropathy, the P100 peak latency of PVECP shortened as visual acuity improved. The VECP abnormalities in these patients suggest that there is a severe effect on the optic nerve after prolonged exposure to toluene.

Effects of intravitreal injection of botulinum toxin on the electroretinogram of rats.

The retinal toxicity of botulinum toxin A (BTA) was electroretinographically studied in rats. Sixteen rats were injected intravitreally with 10 ng of BTA. A response-amplitude series was recorded before and 1, 6, 13 and 21 days after the injection of BTA. BTA did not alter the amplitude and the peak latency of the a-wave. The amplitude of the b-wave was not changed except for 2 rats, in which the b-wave was diminished. The peak latency of the b-wave was significantly prolonged after injection of 10 ng BTA (p < 0.05). Except for these latter 2 rats, the results indicated that the dosage used therapeutically appears to have no deleterious effect on retinal integrity or function at least in the short term, but multiple injections or higher doses of BTA could alter retinal function.