Changes in corneal epithelial barrier function after excimer laser photorefractive keratectomy

PURPOSE

To use fluorophotometry to measure corneal epithelial barrier function after excimer laser photorefractive keratectomy (PRK).

SETTING

Seoul National University Hospital, Seoul, Korea.

METHODS

Twenty-five eyes of 21 patients (13 women, 8 men) had PRK to correct myopia. Corneal epithelial healing time was measured and corneal epithelial permeability to sodium fluorescein evaluated by fluorophotometry 1, 2, and 3 weeks after surgery.

RESULTS

Epithelial permeability showed a statistically significant increase 1 week after surgery and returned to its preoperative level 1 week later. Comparative studies according to epithelial healing day and corrected diopter showed results that were not statistically significant (P > .05).

CONCLUSION

These results suggest that PRK delays complete reconstruction of corneal epithelial barrier function. In humans, the corneal epithelium regained its normal barrier function 2 weeks after PRK. Thus, at least during these weeks, care should be taken to minimize further epithelial trauma.

Recurrent herpes zoster myelitis

Recurrent zoster myelitis is quite rare. We present a previously healthy 27-year-old woman who developed recurrent attacks of myelopathy shortly after the characteristic skin rashes of herpes zoster. Magnetic resonance imaging studies demonstrated each lesion in the spinal cord at the same segments as the skin lesions. She had two attacks at opposite sites at the same spinal cord level and complete recovery after being treated with intravenous acyclovir. We suspect that direct invasion of varicella zoster virus was the cause of recurrent myelopathy in our patient.

Large cerebral infarction during praziquantel therapy in neurocysticercosis

BACKGROUND

Large cerebral infarction is a rare complication of neurocysticercosis. Endarteritis by inflammation of the leptomeninges is known to be its cause.

CASE DESCRIPTION

A 59-year-old man with known neurocysticercosis developed a large cerebral infarction during praziquantel therapy. A follow-up MRI obtained immediately after his cerebral infarction demonstrated notable decrease in the size of the cysts and more prominent enhancement around the peripheral margins of the cysts and the major vessels in comparison with the initial MRI. Cerebral angiography disclosed occlusions and narrowing of both internal carotid arteries at the supraclinoid portions, where multiple cysts were found on the MRI.

CONCLUSIONS

Findings in our patient strongly suggest that a secondary inflammation reaction caused by the destruction of the cysts might have enhanced the process of endarteritis. The possible deleterious effects of praziquantel therapy should be considered in the treatment of patients with subarachnoid cysticerci.

Vertigo of cerebrovascular origin proven by CT scan or MRI: pitfalls in clinical differentiation from vertigo of aural origin

To get a better insight into the clinical differentiation between vertigo of cerebrovascular origin and of aural origin, we investigated radiologically proven stroke patients who presented with vertigo as an initial clinical manifestation. Of 154 stroke patients, 30 patients with vertigo (20%) had the relevant lesion, demonstrated with the initial computerized tomographic scan (13 patients) or the follow-up magnetic resonance imaging (MRI) study (17 patients) of the brain. Every lesion was in the vertebrobasilar arterial territory; 19 in the cerebellum, 8 in the pons, and 3 in the medulla oblongata. Although 12 of the 30 patients (40%) presented with vertigo in isolation at the onset of stroke, eight patients (27%) developed additional neurologic abnormalities from four hours to seven days later. Patients with isolated vertigo (13%) had the small lesion exclusively in the cerebellum of the PICA medial branch territory. The most frequent accompanying neurological sign was swaying in the cerebellar and medullary lesion, and dysarthria in the pontine lesion. The direction of nystagmus or swaying did not match the lesion side in some patients. Our findings suggest that cerebellar stroke may commonly manifest isolated vertigo or vertigo with swaying mimicking labyrinthine disorder, particularly at the onset of the disease. MRI study and tests for truncal ataxia and lateropulsion may be crucial for the detection of vertigo of cerebrovascular origin.

Pure motor hemiplegia with conjugate lateral gaze palsy in pontine lacunar infarction

The combination of pure motor hemiplegia and horizontal gaze palsy is a rare but identifiable lacunar syndrome. Among horizontal gaze palsies, one-and-a-half syndrome and abducens nerve palsy are reported to be associated with pure motor hemiplegia in pontine lacunar infarction. Although conjugate lateral gaze palsy is also hypothesized, pure motor hemiplegia with conjugate lateral gaze palsy has never been reported. We present a 75-year-old man who showed right hemiparesis and impaired left horizontal conjugate eyeball movement. Both the findings of the brain CT scan and those of the MRI study were consistent with a small infarction in the left midpontine tegmentum. Magnetic resonance angiography revealed no stenotic narrowing of the vertebrobasilar artery. Radiological findings suggested that pure motor hemiplegia with conjugate lateral gaze palsy, in our patient, might have been produced by the occlusion of a single penetrating branch of the basilar artery.

Dimethylthiourea prevents MPTP-induced decrease in [3H]dopamine uptake in rat striatal slices

To determine whether oxygen free radicals are involved in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity, the effect of dimethylthiourea (DMTU), an effective hydroxyl radical scavenger, on MPTP-induced changes of [3H]dopamine uptake was investigated in rat striatal slices. The uptake of [3H]dopamine was decreased by MPTP treatment, and DMTU prevented the MPTP-induced decrease of [3H]dopamine uptake in a dose-dependent manner. The highest dose of DMTU used in this study completely prevented the MPTP-induced decrease of [3H]dopamine uptake. These results indicate that free radicals play a major role in the pathogenetic mechanism of MPTP-induced neurotoxicity.