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.

Physiologic and morphologic retinal changes induced by murine cytomegalovirus in BALB/c and severe combined immune deficient mice.

Anterior chamber inoculation of murine cytomegalovirus (MCMV, 10(4) and 10(5) plaque-forming units) induced both physiologic and morphologic changes in the retinas of immunocompetent BALB/c and B- and T-cell-deficient severe combined immune deficient (SCID) mice. In BALB/c mice, the depression of the b-wave began on days 3-4 postinoculation (PI) and a further depression was recorded on day 7 PI. The electroretinograms (ERGs) remained depressed 1-2 weeks PI after which there was a recovery of the amplitude of the ERG 2-6 weeks later. The recovery was not complete; the maximum amplitude at 6 weeks was significantly lower than the preinoculation value. There was a greater loss in the amplitude than in the sensitivity of the ERG. Histologic examination of retinas with depressed ERGs showed swelling of the retinal pigment epithelium and distortion and shortening of the outer segment of the photoreceptors. With recovery of the ERG, there was normalization of the retinal histology. In SCID mice, the ERGs were extinguished, and there was no recovery. Histologically, there was a complete loss of the photoreceptors in the SCIDs, and electron microscopic examination showed viral particles in the retinal pigment epithelium and inner nuclear cells. These results demonstrate that MCMV can induce retinal pathology as reported in patients and show the importance of B- and T-lymphocytes in controlling the progression of this disease process.

Transient increase of b-wave in the mouse retina after sodium iodate injection.

Twenty C57 black mice received an injection of 40 mg/kg of sodium iodate through the caudal vein. The electroretinograms (ERGs) were recorded before and after injection. Flash stimuli with the maximum illuminance, 30,000 lux, were given at increasing levels of illuminance in 0.6 log U steps for 13 levels of intensity. The a- and b-wave amplitudes increased linearly with increased stimulus intensity for approximately 5.0 log U before being saturated. Twenty four hours after injection, the intensity-amplitude curve shifted toward the higher intensity region. It was calculated that the sensitivity loss of the b-wave after injection was 2.0 log U, although the maximum amplitude was larger and the peak latency was delayed. The same results were seen less obviously in the ERGs 48 hr after injection. After 96 hr, both waves were greatly attenuated and even abolished. At the time the increased ERGs were recorded, the histopathologic findings exhibited severe damage of the retina in the pigment epithelium and in the outer layer.

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.

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.

Functional recovery of retina after sodium iodate injection in mice.

ERGs and the azide responses were recorded from mice before and periodically up to 6 weeks after retinal pigment epithelium (RPE) damage by iodate injection to follow the recovery of retinal pigment epithelium and retinal function. At 14 days postinjection, there was a partial recovery of the maximal b-wave amplitude and the azide response but no further recovery was found after 14 days. The retinal sensitivity showed a slow recovery, and at 6 weeks postinjection did not differ from the pre-iodate sensitivity. These findings correlated with histological observations. We concluded that the recovery in ERGs resulted from RPE recovery and the large patchy area of recovered retina functioned normally.

Alterations of the electroretinogram by intravitreal kainic acid in the rat.

PURPOSE: To relate the electrophysiological changes in the retina induced by the excitatory neurotoxin, kainic acid (KA), to its receptor sites in the rat. METHODS: Fifty-five Wistar rats were injected intravitreally with 100, 50, 25, 12.5, 6.25, 3.12, or 1.56 nmol of KA. The electroretinograms (ERGs) including oscillatory potentials (OPs) elicited by a series of increasing intensities were recorded before, and 6 hours, 1 day, 1 week, and 1 month after the injection of KA. RESULTS: After KA injection, the a-waves showed no significant change at all intensity levels (P > .05), but the amplitudes and implicit times of the b-wave were significantly altered. The abolition of the b-wave by KA resulted in a negative response, which decreased progressively with time. The implicit times of the b-wave showed a marked prolongation after injection of 100 nmol of KA (P < .01). The OPs disappeared at the KA dose of 6.25 nmol and higher; doses of 1.56 to 3.12 nmol of KA depressed the Ops. CONCLUSIONS: We conclude that KA altered the above-mentioned ERG components in a dose-dependent manner. These alterations of the ERG can be explained by alterations of neurons in the inner retinal layers.

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.

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.

[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.

[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.

[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.

Electroretinographic effects of haloperidol on the mouse retina.

The effects of haloperidol on the electroretinogram were studied in mice injected intraperitoneally with haloperidol. A dose-related study was performed. A significant decrease in the amplitude of the b-wave was found in the mice injected with more than 20 mg/kg of haloperidol. However, the peak latency of the b-wave and the stimulus intensity required to elicit a b-wave of one half of the maximum b-wave amplitude remained unchanged. No significant changes were found in the a-wave. This change in the electroretinogram recovered 24 hours after the injection. These results suggest that functional change occurred at the retinal level after intraperitoneal injection of haloperidol.

Clinical application of the pattern electroretinogram with lid skin electrode.

Pattern evoked potentials were recorded simultaneously with an electrode placed on the skin of the lower eyelid, gold foil electrodes hooked on the right and left eyelids, and a skin electrode at Oz in normal subjects and in patients with optic nerve and macular diseases. Peak latencies and amplitudes of the pattern electroretinogram (PERG) were compared between the two electrodes. In both records, the peak latency showed no difference at 56.7 +/- 2.9 ms (mean +/- S.D.), while the amplitude of the PERG with the lid skin electrode was at 1.2 +/- 0.3 microV, approximately one-third of that obtained with the gold foil electrode. Although the skin electrode did not always record responses as well as the gold foil, its advantages recommend its use in clinical cases.

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.