Movement-Related Potentials Associated with Motor Timing Errors as Determined by Internally Cued Movement Onset

Objective@#Accurate motor timing is critical for efficient motor control of behaviors; however, the effect of motor timing abilities on movement-related neural activities has rarely been investigated. The current study aimed to examine the electrophysiological correlates of motor timing errors. @*Methods@#Twenty-two healthy volunteers performed motor timing tasks while their electroencephalographic and electromyographic (EMG) activities were simultaneously recorded. The average of intervals between consecutive EMG onsets was calculated separately for each subject. Motor timing error was calculated as an absolute discrepancy value between the subjects’ produced and given time interval. A movement-related potential (MRP) analysis was conducted using readings from Cz electrode. @*Results@#Motor timing errors and MRPs were significantly correlated. Our principal finding was that only Bereitschaftpotential (BP) and motor potential (MP), not movement monitoring potential, were significantly attenuated in individuals with motor timing errors. Motor timing error had a significant effect on the amplitude of the late BP and MP. @*Conclusion@#The findings provide electrophysiological evidence that motor timing errors correlate with the neural processes involved in the generation of self-initiated voluntary movement. Alterations in MRPs reflect central motor control processes and may be indicative of motor timing deficits.

Movement-Related Potentials Associated with Motor Timing Errors as Determined by Internally Cued Movement Onset

Objective@#Accurate motor timing is critical for efficient motor control of behaviors; however, the effect of motor timing abilities on movement-related neural activities has rarely been investigated. The current study aimed to examine the electrophysiological correlates of motor timing errors. @*Methods@#Twenty-two healthy volunteers performed motor timing tasks while their electroencephalographic and electromyographic (EMG) activities were simultaneously recorded. The average of intervals between consecutive EMG onsets was calculated separately for each subject. Motor timing error was calculated as an absolute discrepancy value between the subjects’ produced and given time interval. A movement-related potential (MRP) analysis was conducted using readings from Cz electrode. @*Results@#Motor timing errors and MRPs were significantly correlated. Our principal finding was that only Bereitschaftpotential (BP) and motor potential (MP), not movement monitoring potential, were significantly attenuated in individuals with motor timing errors. Motor timing error had a significant effect on the amplitude of the late BP and MP. @*Conclusion@#The findings provide electrophysiological evidence that motor timing errors correlate with the neural processes involved in the generation of self-initiated voluntary movement. Alterations in MRPs reflect central motor control processes and may be indicative of motor timing deficits.

Intravitreal Triamcinolone Acetonide Injection at the Time of Pars Plana Vitrectomy for Retained Lens Material

PURPOSE: To report the experiences at our institute of pars plana vitrectomy (PPV) in combination with intravitreal triamcinolone acetonide (IVTA) injection in patients with retained lens material after cataract surgery. METHODS: The medical records of patients who underwent PPV between January 2005 and December 2006 after complicated cataract surgery in which lens material was dropped into the vitreous cavity were reviewed retrospectively. RESULTS: Five eyes of five patients were treated by vitrectomy and removal of the dislocated lens material and were administered an adjuvant intravitreal injection of 4 mg triamcinolone acetonide at the end of surgery. IVTA administration induced a rapid improvement in vision within six weeks postoperatively. Final visual acuity was 20/32 or better in all patients. Inflammatory cystoid macular edema (CME) that existed preoperatively was promptly improved after IVTA. Intraocular pressure increased transiently in one patient. No procedure-related complications were observed. CONCLUSIONS: PPV with additional IVTA was successfully performed in five eyes with retained lens material and resulted in a marked resolution of vitreous inflammation, an improvement in CME and rapid visual recovery. The authors recommend that IVTA administration should be investigated more thoroughly as an adjunct during the management of retained lens material.

A Case of Valganciclovir Treatment for Cytomegalovirus Retinitis

PURPOSE: To report a case of a patient with cytomegalovirus (CMV) retinitis who was treated with oral valganciclovir. CASE SUMMARY: A 34-year-old man who had undergone anti-cancer chemotherapy for Non-Hodgkin lymphoma was referred to the ophthalmologic oncology clinic because of decreased vision in both eyes. Fundus examination showed white, opaque, and granular retinal lesions in both eyes, and a serologic test showed a positive response to CMV antibody IgG and a negative response to CMV antibody IgM. The patient received induction therapy with intravenous ganciclovir and maintenance therapy with oral valganciclovir 900 mg once daily. CMV retinitis reactivated 4 weeks after maintenance therapy was discontinued. At that point, the patient received induction therapy with oral valganciclovir 900 mg twice daily for 3 weeks and maintenance therapy with 900 mg once daily for 5 weeks. The retinal lesion disappeared and did not recur after oral administration of valganciclovir. The patient discontinued valganciclovir after 5 weeks of maintenance therapy, and CMV retinitis did not reactivate during 6 months of follow-up. CONCLUSIONS: Oral valganciclovir was clinically effective in the treatment of CMV retinitis in a patient who was treated with anti-cancer chemotherapy for non-Hodgkin lymphoma.

Differentiation and Transdifferentiation of Lens Epithelial Cells in Capsular Bag Model Culture

PURPOSE: To investigate the differentiation of lens epithelial cells (LECs) to lens fiber, and the transdifferentiation of LECs to fibroblast in capsular bag culture. METHODS: After observing the changes of LECs by using phase-contrast microscopy, we observed a cross section of capsular bag by using light microscope (LM) and electron microscope (EM). In addition, the expressions of alpha A-crystallin, a marker of differentiation of LEC to lens fiber, and of alpha-smooth muscle actin, a marker of LEC to fibroblast, were examined during the culture period by western blot. RESULTS: On phase-contrast microscopy, 7 to 14 days after culture, the portion of LECs was gradually elongated and cytoplasm became transparent, so that the differentiation resembled lens fiber. One to 7 days after culture, the portion of LECs changed to spindle shape and the transdifferentiation resembled fibroblast. LM and EM observations indicated that changes of each LEC were lens fiber, and fibroblast. According to Western blot, the expression of alpha A-crystallin was increased by 10 days after culture. The alpha-smooth muscle actin showed an increased expression 10 to 30 days after culture. CONCLUSIONS: From the capsular bag model, we observed the resemblances of the differentiation and transdifferentiation of LECs with lens fiber and fibroblast.

Transthoracic Echocardiography and Carotid Doppler Ultrasound for Detection of Cardiac and Carotid Artery Disease in Patients with Acute Retinal Artery Obstruction

We reviewed the medical records of patients with acute retinal artery obstruction (RAO) and evaluated the importance of transthoracic echocardiography (TTE) and carotid Doppler ultrasound in determining causes of cardiac and carotid artery origin in RAO. A retrospective case study conducted in the Department of Ophthalmology, Inha University Hospital, Korea comprised 26 patients presenting with acute RAO who underwent systemic evaluation, TTE and carotid Doppler ultrasound between June 1, 1997 and December 31, 2003. Among these 26 patients, abnormal cardiac findings were detected in 12 (46%) and abnormal carotid findings in 4 (15%). Furthermore, other risk factors for RAO were found in 2 (8%) and stroke broke out within 7 months after experiencing RAO in 4 (15%) of the 26 patients. In patients with acute RAO, TTE and carotid Doppler ultrasound play an important role in pinpointing the origins of retinal emboli. It is thought that TTE and carotid Doppler ultrasound may be essential examinations for determining the underlying cause, planning treatment strategies, and preventing stroke and death.

Effect of PRP on Visual Acuity, Visual Field and Subjective Symptoms in Very Severe NPDR

PURPOSE: To evaluate the effect of panretinal photocoagulation (PRP) on visual acuity, visual field and subjective symptoms in very severe non-proliferative diabetic retinopathy (NPDR) patients. METHODS: Forty eyes of 20 patients with NPDR were evaluated. Complete ophthalmic examination, visual acuity, Humphrey field test and interview of questionnaire were evaluated before, 2 and 8 weeks after PRP. RESULTS: The mean corrected visual acuity was not significantly changed from before PRP to 2, 8 weeks after PRP (p>0.05). Visual field deteriorated in 2 weeks and then improved in 8 weeks after PRP, however the recovery did not reach to pre-PRP level (p0.05). Thoses number decreased in 15~30degrees field (p<0.01) following PRP. In spite of deterioration of visual field after PRP, subjective symptoms was rarely noted. CONCLUSIONS: Our result suggest that early PRP may be advisable for very severe NPDR patients to prevent the development of possible visual field deterioration following PRP.

Triscaphe Fusion with Radial Styloidectomy in Kienbock's Disease / 대한정형외과학회잡지

Neither the cause nor the correct treatment of Kienbocks disease has been clearly established, but its clinical and radiologic presentations have been distinctly defined. There are many controversies concerning therapeutic guidelines for the treatment of Kienbocks disease. The purpose of this study is to evaluate the clinical result of triscaphe fusion with radial styloidectomy of Kienbocks disease. Ten cases of stage III Kienbocks disease by Lichtmans classification were treated by triscaphe fusion with radial styloidectomy from September 1991 to March 1997. We followed up over 24 months and evaluated clinical results. In all cases, pain was relieved. The postoperative results according to Kuschners method revealed three excellent, six good and one fair. The triscaphe fusion and radial styloidectomy was considered as useful method of treatment which has clinical efficacy in Kienbocks disease.

Treatment of Freiberg's Disease with Joint Debridement and Reshaping of Metatarsal Head / 대한정형외과학회잡지

Freibergs disease is avascular necrosis of the second or third metatarsal bone. Since 1914, numerous causes and treatments have been proposed but no definite single cause and treatment method were developed. The simple method, joint debridement could not recover the pathophysiologic condition of Freibergs disease and the destructive method, metatarsal head resection and prosthetic replacement arthroplasty had many postoperative problems. Recently, dorsiflexion osteotomy, which was described by Gauthier and Elbaz for the first time, and joint debridement and reshaping of the metatarsal head, which was described by Mann, were very effective method to manage Freibergs disease. This paper was aimed to evaluate the result of joint debridement and reshaping of the metatarsal head which were relatively simple, less destructive and safe method in treatment of the advanced Freibergs disease. We treated 7 cases of Freibergs disease from August 1993 to March 1997. The results were as follows: 1. All the patients of the last follow-up improved pain. 2. The passive range of motion was increased from 39.1 preoperatively to 57.6 postoperatively. 3. Follow-up X-rays showed no loose body and further metatarsal head destruction. The above results suggested that the joint debridement and reshaping of metatarsal head provided good result in the treatment of advanced Freibergs disease.

A case of Bartter's syndrome

Bartter's syndrome is a rare tubular disorder characterized by hypokalemic, hypochloremic metabolic alkalosis, hyperreninemic hyperaldosteronism, hyporesponsiveness to pressor agents, and juxtaglomerular apparatus hyperplasia. We report here a case of Bartter's syndrome in a 5 month-old male infant who improved with potassium supplements. In addition to a case report, brief review of related literatures was done.

A clinical study on wheezing of mycoplasma pneumoniae pneumonia in children

The relationship between respiratory infections and exacerbations of wheezing in patients with wheezy bronchitis or asthma has been described. Most respiratory infections were viral or Mycoplasma pneumoniae. This study was performed to evaluate the effect of Mycoplasma pneumoniae infection on bronchial reactivity and atopic background. 106 patients with Mycoplasma pneumoniae pneumonia who were admitted to the department of pediatrics, Fatima Hospital, Taegu during the period of two years from January 1989 to December 1990 were involved in this study. The results were as follows 1) Out of 106 cases, 69 were male,37 were female and 34.9% of the cases were between 5~6 years of age. 35 cases(33.0%) had wheezing and the incidence of wheezing were higher in male than in female. 2) The incidence of wheezing was high in the patients with serum IgE level higher than 200IU/ml, patients with past and family history of allergy and the patients fed with formula feeding in infancy. 3) Eosinophils and the associated maxillary sinusitis had no effect on the incidence of wheezing. 4) The recurrence of wheezing was higher in Mycoplasma pneumoniae pneumonia with wheezing(26.8%) than in patients without wheezing(3.8%).