Hypertrophy of IMC of carotid artery in Parkinson's disease is associated with L-DOPA, homocysteine, and MTHFR genotype.

In recent years, an intense interest has developed in the association between Parkinson's disease (PD) and hyperhomocysteinemia. Homocysteine (Hcy) is a neuronal excitotoxic amino acid, and is well known as a risk factor for vascular diseases. Some reports suggest that the administration of L-DOPA may promote hyperhomocysteinemia and idiopathic atherosclerosis. In this study, we report that a mild hypertrophy of the intima-media complex (IMC) of the carotid artery, which has been established as a marker for systemic atherosclerosis, is observed in PD patients compared with normal subjects. PD patients that were treated with L-DOPA for long durations showed a hypertrophic IMC, while the patients that were not treated with L-DOPA did not show any hypertrophic changes in the IMC. These hypertrophic changes were observed primarily in patients with a Hoehn-Yahr stage of 3-5. PD patients with hypertrophic IMC of the carotid artery also exhibited elevated plasma levels of Hcy associated with the C677T genotype of 5,10-methylenetetrahydrofolate reductase (MTHFR). Moreover, a prolonged duration of treatment with L-DOPA in patients with MTHFR T/T genotype enhanced the hypertrophy of IMC, compared with patients with the C/C or C/T genotype. These results suggest that hyperhomocysteinemia promoted by the C677T genotype of MTHFR and prolonged treatment with L-DOPA enhances atherosclerosis in PD patients and affects their general condition.

[A case of non-paralytic pontine exotropia with vertical dissociated nystagmus in the contralateral eye].

We report a 74-year-old woman presenting non-paralytic pontine exotropia (NPPE) with vertical monocular nystagmus in her contralateral eye, due to a small infarction in the upper pons. On forward gaze, the ocular position of the right eye was fixed at the midline, while the left eye was abducted. On the leftward gaze, the left eye was abducted and monocular nystagmus was noted, but the right eye was not able to pass midline, which indicated NPPE. Neither a skew deviation nor an alternating exotropia was observed. In the acute phase of this case, disturbances in the vertical eye movement of her right eye and the monocular upper gaze-evoked nystagmus of her left eye were observed. On the 7th hospital day, the monocular nystagmus disappeared simultaneously with an improvement of vertical eye movement. This finding suggests that the patient's vertical monocular nystagmus occurred due to an adaptive increase in the innervation to the left eye according to Hering's law of equal innervation, which indicates either horizontal dissociated nystagmus in MLF syndrome or NPPE.