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Biomedical subjects

S A Park

Publications and source records attributed to S A Park.

At least 19 recordsLinked to original sources
PubMed2005

Bupivacaine induces apoptosis via ROS in the Schwann cell line.

Local anesthetics have been generally accepted as being safe. However, recent clinical trials and basic studies have provided strong evidence for the neurotoxicity of local anesthetics, especially through apoptosis. We hypothesized that local anesthetics cause neural complications through Schwann cell apoptosis. Among local anesthetics tested on the Schwann cell line, RT4-D6P2T, bupivacaine significantly induced cell death, measured by the methyl tetrazolium (MTT) assay, in a dose- (LD50 = 476 microM) and time-dependent manner. The bupivacaine-induced generation of reactive oxygen species (ROS), which was initiated within 5 hrs and preceded the activation of caspase-3 and poly ADP-ribose polymerase (PARP) degradation, was suggested to trigger apoptosis, exhibited by Hoechst 33258 nuclear staining and DNA fragmentation. Furthermore, concomitant block of ROS by anti-oxidants significantly inhibited bupivacaine-induced apoptosis. Among the local anesthetics for peripheral neural blocks, bupivacaine induced apoptosis in the Schwann cell line, which may be associated with ROS production.

Analysis of Variance↗
PubMed2003

Thyrotoxic autoimmune encephalopathy: a repeat positron emission tomography study.

Thyroid related autoantibodies have been related to the development of encephalopathy, known as Hashimoto's encephalopathy. However, their relation with the encephalopathy occurring in patients with Graves' disease has not been well established. The case is reported of a 51 year old woman presenting with subacute progressive dementia with evidence of hyperthyroidism. She had Graves' disease associated with high titres of thyroid related autoantibodies. Her encephalopathy was not improved by antithyroid drugs, but promptly responded to corticosteroid treatment, and stabilised with a gradual reduction of thyroid related autoantibody titres. Brain positron emission tomography initially showed a diffuse and multifocal cerebral hypometabolism with subsequent normalisation on her clinical recovery, which was consistent with the acute and reversible cerebral inflammation probably mediated by autoimmune mechanisms.

Autoantibodies↗
PubMed2002

Ictal electrocorticographic findings related with surgical outcomes in nonlesional neocortical epilepsy.

PURPOSE: To characterize ictal electrocorticographic features related to surgical outcomes in nonlesional neocortical epilepsy (NE). METHODS: We analyzed 187 ictal electrocorticograms (ECoG) obtained from 18 patients who had undergone presurgical evaluation and subsequent neocortical resections (frontal: seven, parietal: one, occipital: four, multilobar: six). None of them had any MRI-detectable lesions. Various ECoG data sets recorded from eight patients who achieved a favorable surgical outcome (either seizure free or more than 90% reduction of seizure frequencies) were compared with that from ten patients with unfavorable outcome (less than 90% reduction of seizure frequencies) (follow up duration: 47+/-11 months). RESULTS: Reproducible ictal onset zone (IOZ) in recurrent seizures (P=0.013) and persistent ictal discharges in IOZ from the onset to the end of seizure (P=0.004) were found more frequently in the patients with good outcome. Ictal onset patterns consisting of low voltage fast or high amplitude beta spikes predicted a good surgical outcome while rhythmic sinusoidal activity or rhythmic spike/sharp waves of slow frequency were predictive of poor outcome (P=0.01). The ictal onset rhythm consisting of gamma or beta frequencies was more prevalent in the favorable group (P=0.015). CONCLUSIONS: The presence of stable ictal circuit suggested by the consistent earliest activation of specific electrodes in the repetitive seizures (reproducible IOZ) and the active participation of IOZ throughout the attack were valuable prognostic factors in addition to the morphology and frequency of ictal onset rhythm.

Adolescent↗
PubMed2001

Bcl-2 blocks cisplatin-induced apoptosis by suppression of ERK-mediated p53 accumulation in B104 cells.

Bcl-2 has been reported to inhibit neurotoxicity induced by cisplatin. However, neither the mechanism of cisplatin-induced neurotoxicity nor the mechanism by which Bcl-2 confers neuroprotection is clear. In this study, the signaling pathways involved in cisplatin-induced neurotoxicity were examined using a rat neuroblastoma cell line, B104. Treatment of B104 cells with cisplatin induced apoptosis, accompanying the accumulation of p53 and Bax protein. Interestingly, extracellular signal-regulated kinase 1/2 (ERK1/2) activities of MAP kinases were markedly enhanced prior to cisplatin-induced accumulation of p53 and Bax. Inhibition of ERK1/2 activities using PD98059, a selective MEK inhibitor, blocked the apoptotic cell death preventing cisplatin-induced accumulation of p53 and Bax. These results suggest that ERK mediates cisplatin-induced p53 activation to trigger apoptosis in B104 cells. Overexpression of Bcl-2 in B104 cells resulted in the complete resistance to cisplatin-induced apoptosis blocking ERK activation and the subsequent signaling pathway of p53. Our study clearly demonstrates that the action site of Bcl-2 localizes upstream of ERK in cisplatin-induced apoptotic signaling pathway.

Animals↗
PubMed2001

His-His-Leu, an angiotensin I converting enzyme inhibitory peptide derived from Korean soybean paste, exerts antihypertensive activity in vivo.

It has been reported that soybean peptide fractions isolated from Korean fermented soybean paste exert angiotensin I converting enzyme (ACE) inhibitory activity in vitro. In this study, further purification and identification of the most active fraction inhibiting ACE activity were performed, and its antihypertensive activity in vivo was confirmed. Subsequently, a novel ACE inhibitory peptide was isolated by preparative HPLC. The amino acid sequence of the isolated peptide was identified as His-His-Leu (HHL) by Edman degradation. The IC(50) value of the HHL for ACE activity was 2.2 microg/mL in vitro. Moreover, the synthetic tripeptide HHL (spHHL) resulted in a significant decrease of ACE activity in the aorta and led to lowered systolic blood pressure (SBP) in spontaneously hypertensive (SH) rats compared to control. Triple injections of spHHL, 5 mg/kg of body weight/injection resulted in a significant decrease of SBP by 61 mmHg (p < 0.01) after the third injection. These results demonstrated that the ACE inhibitory peptide HHL derived from Korean fermented soybean paste exerted antihypertensive activity in vivo.

Amino Acid Sequence↗
PubMed2001

Ictal automatisms with preserved responsiveness in a patient with left mesial temporal lobe epilepsy.

PURPOSE: To describe the possible mechanism of ictal automatisms with preserved responsiveness (APRs) in a patient with left mesial temporal lobe epilepsy, which had not been reported previously. METHODS: Ictal EEGs recorded from bilateral foramen ovale electrodes with scalp-sphenoidal electrodes were analyzed in respect to the ictal semiology. RESULTS: The patient had a right hemispheric language dominance in the dextral. Electroclinical analysis revealed that the onset of oroalimentary automatisms coincided with the involvement of the left mesial and lateral temporal structures by spreading ictal discharges. The ictal discharge spreading was limited to the ipsilateral hemisphere throughout the seizure, which explained the intact consciousness and preserved responsiveness of the patient. CONCLUSIONS: This case suggests that APRs take place in seizures originating from the nondominant temporal lobe, during which ipsilateral mesial and lateral temporal structures are diffusely involved without spreading to the contralateral side.

Adolescent↗
PubMed2000

Memory deficits after bilateral anterior fornix infarction.

The authors report a patient who suddenly developed memory loss without any other focal neurologic deficits. Neuropsychological testing showed severe anterograde verbal and visual memory deficits that improved gradually over several months, but not to the point of the premorbid state. Brain MRI with diffusion-weighted imaging performed 3 days after onset revealed acute infarction involving the bilateral fornices and the right genu of the corpus callosum. The authors suggest that acute fornix infarction may cause anterograde memory deficits.

Cerebral Infarction↗
PubMed2000

Cisplatin-induced apoptotic cell death in mouse hybrid neurons is blocked by antioxidants through suppression of cisplatin-mediated accumulation of p53 but not of Fas/Fas ligand.

Peripheral neuropathy following cisplatin treatment is a major limiting factor in cisplatin chemotherapy of cancer patients. We investigated the pathomechanism underlying cisplatin neuropathy using a mouse dorsal root ganglion neuron-neuroblastoma hybrid cell line (N18D3) developed in our laboratory. DNA fragmentation, a characteristic feature of apoptosis, was induced in hybrid neurons following treatment with cisplatin. Accumulation of p53, Fas, and Fas ligand (Fas-L) was also demonstrated in these neurons. Preincubation with N-acetylcysteine (NAC), a precursor of glutathione, blocked cisplatin-induced apoptosis completely, whereas Trolox, a vitamin E analogue, blocked it partially. Cisplatin-induced p53 accumulation was suppressed by NAC treatment, whereas p53 accumulation was retarded by Trolox treatment. In contrast, neither NAC nor Trolox showed any inhibitory effect on cisplatin-induced Fas/Fas-L accumulation. These results suggest that the neuroprotective effects of antioxidants against cisplatin-induced neurotoxicity in hybrid neurons are mediated mainly through the inhibition of p53 accumulation but not of Fas/Fas-L accumulation by these antioxidants.

Acetylcysteine↗
PubMed1998

Clinical courses of pure sleep epilepsies.

This study aims to understand seizure control outcomes and the risk of developing new wake seizures (WS) related to the different types of pure sleep epilepsies (SE), which is important in making rational management plans. A retrospective review of the Yonsei Epilepsy Clinic Registry identified 63 patients with pure SE not belonging to any specific epileptic syndromes. They were divided into the group of generalized tonic-clonic seizures during sleep (S-GTCS : n = 21) and the group of partial epilepsies during sleep (S-PE: n = 42) on the basis of seizure phenomenology, EEG, and neuroimaging data. These patients were followed for 2 years and their clinical variables were analysed for seizure control outcomes and development of new WS. Of 21 patients with S-GTCS, 17 achieved a seizure-free outcome and only one patient developed a new WS, which was consistent with a partial-onset secondary GTCS in phenomenology. Of 42 patients with S-PE only 15 patients achieved a seizure-free outcome and 11 patients developed WS during the 2-year follow-up period. Higher baseline seizure frequency and longer duration of epilepsy were associated with a higher incidence of new WS. The results suggest that the patients with S-GTCS carry a favorable clinical course, thus driving privileges or freedom of daily activities can be conferred without delay once their seizures are well controlled. However, the seizure control outcome was poor and the development of WS was frequent in patients with recurrent S-PE.

Adolescent↗
PubMed1997

Locked-in syndrome with bilateral peduncular infarct.

Locked-in syndrome due to midbrain infarct is very rare. This report describes a patient with locked-in syndrome whose magnetic resonance images showed bilateral infarcts in the cerebral peduncle. Cerebral angiography disclosed bilateral irregular thrombotic narrowing of the vertebral and proximal basilar arteries with rostral basilar artery occlusion, a previously unreported findings.

Cerebral Angiography↗
PubMed1997

Experiences of epilepsy surgery in intractable seizures with past history of CNS infection.

We studied the clinical characteristics, location of epileptogenic regions, and the surgical outcomes in 18 patients with intractable epilepsy associated with previous CNS infections. All patients underwent an extensive presurgical evaluation and 11 patients had intracranial EEG monitoring. On the basis of presurgical evaluation, epileptic regions were localized to the mesial temporal (n = 12) and the neocortical (n = 6) regions. The age of the time of CNS infection was significantly younger and the latent period of non-febrile seizures after CNS infection was longer in patients with mesial temporal lobe epilepsy (MTLE). MRI showed hippocampal atrophy and hippocampal signal changes in 11 of 12 patients with MTLE. Among 6 patients with neocortical epilepsy (NE) 5 patients had normal MRI and one showed cerebral hemi-atrophy. Surgery was successful (class I & II) in all patients with MTLE, however, in the patients with neocortical epilepsy, seizure-free results were not achieved in any patients after resective surgery (6 patients) and only 2 patients achieved Class II outcomes after a second epilepsy surgery consisting of neocortical resection. Patients with MTLE after CNS infection were differentiated from the group of neocortical epilepsy by an earlier onset of CNS infection, a prolonged latent period and a higher frequency of meningitis. The characteristic pathology in this group was hippocampal sclerosis and the surgical result was excellent. Neocortical epilepsy following CNS infection usually had no focal lesion on MRI and was associated with a relatively poor surgical result. This study suggested that the surgical outcome was influenced by the type of epileptic syndromes rather than the etiology of seizures. The association of MTLE with the younger age of CNS infections and with meningitis more frequently suggested that the neocortical neurons during infancy or early childhood may be more resistant to the epileptogenesis, or that the CNS infections in patients with MTLE might be milder in severity to cause selective injuries to the hippocampal neurons during their vulnerable stage.

Adolescent↗
PubMed1989

[The use of nursing diagnosis in practice].

This study was conducted to investigate the present situation and problems related to the use of nursing diagnosis in practice. The data were obtained from 332 subjects (27 director of nursing service, 302 staff nurses) who worked in university hospitals in Korea from July through August 1988 using a mailed questionnaire. Data were analyzed by frequency, X2 test and t-test. The findings were as follows: 1. Clinical use of nursing diagnosis by directors of nursing service and staff nurses. 1) The majority of the nursing departments (88.9%) conducted group education on nursing diagnosis during the last 5 years and 81.5% of them kept a record format for nursing diagnosis; 88.9% of them had had prior experience with the nursing diagnosis. 2) Most of nurses (97.0%) had received education on nursing diagnosis. 2. Factors related to the clinical use of nursing diagnosis in nursing service departments and by staff nurses. 1) The one factor related to the use of nursing diagnosis in the nursing service department was the existence of a record. 2) Factors related to the use of nursing diagnosis by the staff nurses were the organization style of the nursing service department, group education during the last 5 years, existence of a record, the attitude of the director of nursing service, and prior experience of the use of the nursing diagnosis as characteristics of nursing service department and educational experience of nursing diagnosis as a character of nurse. 3. Problems with the use of nursing diagnosis. 1) The primary problem was the lack of time and personnel (mean:3.757); the second problem was the lack of knowledge and will to use nursing diagnosis in practice by the staff nurses (mean:3.546). 2) There was no significant difference in problems expressed by the director of nursing services and the nurses. The majority of nurses who worked in the university hospitals expressed interest in and concern about the use of nursing diagnosis. Most of the nurses had had education about on nursing diagnosis but use in practice was limited. The primary problem was lack of time and manpower.(ABSTRACT TRUNCATED AT 400 WORDS)

Attitude of Health Personnel↗
PubMed1989

[The effects of clinical application of a nursing diagnosis protocol].

This study was conducted to measure the effects of clinical application of a Nursing Diagnosis Protocol. The dependent variables were the degree of patient's satisfaction and the degree of nurse's satisfaction with the nursing activity. Analysis of the effect of the use of the nursing diagnosis protocol was based on the nursing record. The subjects for this study were 61 nurses (experimental group 31, control group 30) and 155 patients (experimental group 55, control group 100) on four internal medicine wards in K University Hospital in Seoul.

Clinical Protocols↗