OCT measurements on the foveal and perifoveal retinal thickness on diabetic patients after phacoemulsification and IOL implantation

PURPOSE

The first aim (I.) was to measure the change of macular thickness in diabetic (DM group) and nondiabetic patients (NORMAL group), the values of operated eye (OP) were compared I.A.) to the fellow, non-operated eye (CONTROL) and I.B.) to preoperative baseline value of the operated eye (PRE). The second aim (II.) was to compare postoperative macular thickening of DM group to NORMAL group eyes.

METHODS

Retinal thickness values of the foveal and perifoveal (fovea+3.0 mm, fovea+6.0 mm) sectors and the minimum values were measured in a prospective study using optical coherence tomography (OCT) in 18 eyes of 18 diabetic patients and 53 eyes of 53 nondiabetic patients who underwent uneventful cataract surgery. Data were collected on the preoperative day and on postoperative 1, 7, 30, and 60 days. Student's t-test was used for statistical analysis.

RESULTS

No significant change of the thickness values could be measured one day after surgery. However, a significant increase could be detected on the postoperative 7, 30, and 60 days in the perifoveal 3.0 mm and 6.0 mm sectors either calculated alone or averaged together with the foveal values. The initial (preoperative) average value of 232.7+/-3.5 microm (mean+/-SEM, n=144) in the 6.0 mm perifoveal region increased to 246.0+/-8.2 microm (mean+/-SEM, n=120, P=0.032) one week, to 249.9+/-5.1 microm (n=112, P=0.017) one month, and to 249.5+/-6.2 microm (n=104, P=0.009) 2 months after surgery.

DISCUSSION

Our results indicate that diabetes did not influence significantly the thickening of the macular regions after uncomplicated cataract surgery.

Change of foveal and perifoveal thickness measured by OCT after phacoemulsification and IOL implantation

PURPOSE

Cataract surgery is known to elicit postoperative macular oedema owing to its traumatic effect. The aim of the study was to measure the foveal and perifoveal thickness of the retina after uneventful phacoemulsification and posterior chamber intraocular lens (PC-IOL) implantation.

METHODS

Retinal thickness values of the foveal and perifoveal (fovea+3.0 mm, fovea+6.0 mm) sectors and the minimum values were measured in a prospective study using optical coherence tomography (OCT) in 71 eyes of 71 patients (34 men, 37 women, mean age: 68.8 years) who underwent cataract surgery. Phacoemulsification and 'in the bag' implantation of a foldable PC-IOL was performed under topical anaesthesia. Data were collected 1 day before the operation, and postoperatively at 1, 7, 30, and 60 days. Contralateral eyes of each patient served as controls. 'Student's t-test' was used for statistical analysis, and P<0.05 value was considered significant.

RESULTS

No significant change of the thickness values could be measured 1 day after surgery. However, a significant increase could be detected on the postoperative 7, 30, and 60 days in the perifoveal 3.0 and 6.0 mm sectors either calculated alone or averaged together with the foveal values. The initial (preoperative) average value of 234.1+/-2.6 microm (mean+/-SEM, n=536) in the 6.0 mm perifoveal region increased to 242.5+/-2.6 microm (mean+/-SEM, n=488, P<0.01) 1 week, to 247.7+/-4.6 microm (n=352, P<0.01) 1 month, and to 246.0+/-5.9 microm (n=208, P<0.05) 2 months after surgery, which proved to be significant. However, the relative change of macular thickness was moderate, 3.5, 5.6, and 5.3% at the above periods, respectively. In a subgroup of patients (n=34) minimum 6 months after cataract surgery, the 6.0 mm perifoveal values were found to be elevated at (237.8+/-3.9 microm, mean+/-SEM, n=272) as compared to the control eyes (233.9+/-3.8 microm, mean+/-SEM, n=272). The difference was 1.7% and proved not to be significant (P>0.05).

CONCLUSIONS

Mild subclinical perifoveal oedema following cataract surgery was detected using OCT at postoperative day 7 to 6 months. The minimal and the foveal values in itself are inadequate to describe the phenomenon. The macular thickness values of the perifoveal 3.0 and 6.0 mm sectors alone or averaged together with the foveal values provide more accurate description of the postoperative macular oedema.OCT enables the detection of minimal increases in perifoveal retinal thickness even 6 months after cataract surgery.

Effect of capsaicin on voltage-gated currents of trigeminal neurones in cell culture and slice preparations

Effects of capsaicin on voltage-gated currents were examined in vitro by whole-cell patch-clamp recordings from small neurones of rat trigeminal ganglia either in slice preparations or in different cell cultures. Cells were classified as sensitive to capsaicin if they responded with inward current and/or conductance change to the agent in nanomolar concentration. Capsaicin (150 to 330 nM) in sensitive cells reduced the mixed inward current evoked by depolarizing step or ramp commands in all preparations. In cultured cells, the inward current was depressed to 32.78 +/- 26.42% (n = 27) of the control. Both the tetrodotoxin-sensitive and -resistant inward currents were affected. The data support the concept that capsaicin besides acting on VR-1 receptors inhibits also some voltage gated channels. In 34 cultured cells, capsaicin increased the slope conductance to 170.5 +/- 68%. Percentage of capsaicin sensitive cells observed in nerve growth factor-treated cultured cell populations was higher (77.8%) than in the two other preparations (14.3 or 38.8%). It is concluded that 1) depression of the voltage-gated currents may play an important role in the functional desensitization of the sensory receptors and in the analgesic effect induced by the agent and 2) cell body of sensory neurones under native condition seems less sensitive to capsaicin then that of cells cultured in the presence of nerve growth factor.

Deterioration of the protein kinase C-K(ATP) channel pathway in regulation of coronary flow in hypercholesterolaemic rabbits

We studied the effect of experimental hypercholesterolaemia/atherosclerosis on changes in coronary flow and cardiac function, induced by protein kinase C and ATP-sensitive K(+) (K(ATP)) channel modulators in isolated Langendorff-perfused rabbit hearts. Both phorbol 12-myristate-13-acetate (PMA) and phorbol 12,13-dibutyrate (PDB, 0.1 microM each), activators of protein kinase C, decreased, whereas staurosporine, (0.1 microM), a protein kinase C inhibitor, increased coronary flow and left ventricular dP/dt, an index of ventricular contractility. Glyburide (5-50 microM), a K(ATP) channel inhibitor, blocked the effect of staurosporine. The phorbol esters were without effect in the presence of pinacidil (5 microM), a K(ATP) channel activator. Neither the protein kinase C modulators nor glyburide produced any effect on coronary flow and left ventricular contractility, when the hearts were prepared from animals either maintained on a cholesterol (1.5%)-enriched diet or treated with lovastatin (5 mg/kg/day per os). Treatment with farnesol (1 mg/kg twice a day for 7 days intravenously) restored the reactivity of hearts from either hypercholesterolaemic or lovastatin-treated animals to protein kinase C modulators. We conclude that non-cholesterol mevalonate products are necessary for the functional integrity of the protein kinase C-K(ATP) channel pathway in the rabbit heart.

Interacting effects of capsaicin and anandamide on intracellular calcium in sensory neurones

Capsaicin (100 nM to 1 microM) and anandamide (200 nM to 10 microM) caused a transient increase in fluorescence of fura-2 loaded cultured small trigeminal neurones of rats measured with a ratiometric technique. The percentage of cells responding to capsaicin at 100 nM, 330 nM and 1 microM was 47.4%, 45.3%, and 70.4%, respectively. Averaged peak value of fluorescense ratio (R) at 340 and 380 nm excitation was slightly dose dependent. Peaks of anandamide-induced transients were R = 0.2 at 200 nM and 0.16 at 10 microM. Near 40% of capsaicin-sensitive cells responded also to anandamide. Anandamide (200 nM) inhibited the capsaicin-induced calcium influx. The results suggest that anandamide increases intracellular calcium and inhibits capsaicin-evoked calcium transients.