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T S Park

Publications and source records attributed to T S Park.

At least 19 recordsLinked to original sources
PubMed2006

Parathyroid hormone (1-34) augments angiopoietin-1 expression in human osteoblast-like cells.

Parathyroid hormone (PTH) is a major regulatory factor in skeletal physiology. However, the molecular mechanism underlying the effects of PTH on bones has yet to be elucidated in detail. Recently, some reports have demonstrated the crucial role of bone vasculature with regard to bone density. Angiopoietin-1 (Ang-1), along with VEGF, has been established as a primary angiogenic regulatory agent. In this study, we have attempted to characterize the effects of PTH (1-34) on Ang-1 expression and signaling molecules, employing primary-cultured human osteoblast-like cells. Quiescent osteoblasts were exposed to PTH (1-34), after which Ang-1 expression was determined at the mRNA and protein levels. Reverse transcription-polymerase chain reaction (RT-PCR) analyses indicated that Ang-1 mRNA expression increased as the result of PTH (1-34) treatment. The expression of the Ang-1 protein was also augmented as the result of treatment with PTH (1-34). An adenylyl cyclase activator, forskolin, was shown to induce Ang-1 mRNA expression, whereas the protein kinase A inhibitor, H-89, blocked the PTH (1-34)-mediated expression of Ang-1 mRNA. These findings indicate that PTH (1-34)-mediated Ang-1 expression involves adenylyl cyclase-protein kinase A dependent signaling. Our observations also show that Ang-1 may perform a crucial role in the effects of PTH (1-34) on bones, possibly involving alterations in bone vasculature.

Angiopoietin-1↗
PubMed2006

Prevalence of erectile dysfunction in Korean men with Type 2 diabetes mellitus.

AIMS: We investigated the prevalence and risk factors for developing erectile dysfunction (ED) in 1312 Korean men with diabetes in a multicentre study. METHODS: We used the modified International Index for Erectile Function-5 criteria to identify mild, moderate and complete ED. A standardized face-to-face questionnaire was used by trained interviewers, and validated against telephone interviews. We recorded the duration of diabetes, level of glycaemic control, vital signs, complications, exercise and alcohol and smoking habits, and diabetes treatments used. Results The mean age and median duration of diabetes were 53.8 +/- 6.65 and 6 years (range 1-43), respectively. The mean HbA(1c) and fasting glucose levels were 7.9 +/- 1.65% and 8.6 +/- 2.82 mmol/l, respectively. The overall prevalences of mild, moderate, complete ED and all ED (mild-to-complete) were 20.1, 19.5, 25.8 and 65.4%, respectively. ED was more common with age, reaching 79.3% in men aged > 60 years. Subjects aged > 60 years and with a duration of diabetes > 10 years were at greatest risk for all ED (OR = 10.4, 95% CI 5.8-18.5, P < 0.001) and complete ED (OR = 13.2, 95% CI 7.3-23.9, P < 0.001) when compared with the reference group (age 40-50 years with duration < 6 years). Age, duration of diabetes, HbA(1c), insulin use, neuropathy and macrovascular complications were positively associated with ED, but alcohol consumption and exercise habits were negatively associated. CONCLUSIONS: The prevalence of complete ED was approximately six times higher than in the general population.

Adult↗
PubMed2006

Prevalence of and risk factors for extracranial internal carotid artery stenosis in Korean Type 2 diabetic patients.

AIMS: The objectives of this study were to evaluate the prevalence of and risk factors for extracranial internal carotid artery stenosis in Type 2 diabetic patients. METHODS: This study included 406 patients aged 40-79 years with Type 2 diabetes (male 55.4%, female 44.6%). Both carotid arteries of each patient were examined by carotid duplex scanning. The duplex ultrasound criteria based on the North American Symptomatic Carotid Endarterectomy Trial (NASCET) measurement method were used for the identification of carotid stenosis. RESULTS: Extracranial internal carotid artery stenosis >or= 40% by velocity criteria was detected in 5.2% of the patients. The prevalence of carotid stenosis increased with advancing age: 1.0% at 40-49 years of age, 5.0% at 50-59 years, 7.3% at 60-69 years and 9.5% at 70-79 years. The degree of stenosis was > 70% in 42.9% of patients with stenosis, Bilateral stenosis was detected in 14% of patients. Of the patients with >or= 40% carotid stenosis, 33% had a decreased ankle-brachial index, 38% had a previous history of stroke, and only one patient (5%) had a documented history of coronary artery disease. Multivariate analysis, including variables determined to be significantly different by univariate analysis between patients with or without >or= 40% stenosis, indicated that age, systolic blood pressure and high-density lipoprotein (HDL)-cholesterol (inverse correlation) were independent risk factors associated with carotid stenosis. CONCLUSIONS: Carotid duplex scanning is a useful strategy in identifying carotid stenosis in older Type 2 diabetic patients with high systolic blood pressure, or low levels of HDL cholesterol. The early identification and subsequent appropriate management of carotid stenosis, particularly in this group of patients, may facilitate efforts to reduce the incidence of macrovascular complications.

Adult↗
PubMed2006

Neural substrates, experimental evidences and functional hypothesis of acupuncture mechanisms.

OBJECTIVES: Although acupuncture therapy has demonstrated itself to be effective in several clinical areas, the underlying mechanisms of acupuncture in general and the analgesic effect in particular are, however, still not clearly delineated. We, therefore, have studied acupuncture analgesic effect through fMRI and proposed a hypothesis, based on the obtained result, which will enlighten the central role of the brain in acupuncture therapy. METHODS: The proposed model, termed as a broad sense hypothalamus-pituitary-adrenal (BS-HPA) axis, was based on our observed neuroimaging results. The model incorporates the stress-induced HPA axis model together with neuro-immune interaction including the cholinergic anti-inflammatory model. RESULTS: The obtained results coupled with accumulating evidence suggest that the central nervous system is essential for the processing of these effects via its modulation of the autonomic nervous system, neuroimmune system and hormonal regulation. CONCLUSIONS: Based on our fMRI study, it appears that understanding the effects of acupuncture within a neuroscience-based framework is vital. Further, we have proposed the broad sense-HPA axis hypothesis which incorporates the experimental results.

Acupuncture Therapy↗
PubMed2005

Management of birth brachial plexus palsy.

INTRODUCTION: The indications for surgical repair of congenital brachial plexus palsy are controversial. Our objective was to determine the results of early brachial plexus surgery following obstetric-induced brachial plexus palsy. METHODS: We performed a retrospective analysis of the outcome of 58 cases of brachial plexus surgery. The indication for operation consisted of the presence of less than antigravity strength in the biceps, triceps, and deltoid muscle groups at 6 months of age. Data gathered prospectively, previously, showed the likelihood of improvement with less than antigravity strength in these cases to be poor. RESULTS: Follow-up data were obtained on 52 of the 58 cases. Overall mean follow-up was 2 years. Twelve patients had more than 3 years follow-up (mean 5.5 years, range 3-11.5 years). Significant improvement was seen in all injury patterns i.e., C5-C6, C5-C7, and C5-C8, T1. Greater than antigravity strength in the biceps, triceps, and deltoid muscle groups was seen in the majority of cases at follow-up. CONCLUSIONS: Repair of obstetrical brachial plexus palsy in children at 6 months of age that is based on less than antigravity strength in the biceps, triceps, and deltoid muscle groups produces improvement in functional capabilities. Children with obstetrical brachial plexus palsy should be referred soon after birth to a center that specializes in the treatment of this type of palsy.

Brachial Plexus Neuropathies↗
PubMed2005

Leukocyte-derived matrix metalloproteinase-9 mediates blood-brain barrier breakdown and is proinflammatory after transient focal cerebral ischemia.

Results of recent studies reveal vascular and neuroprotective effects of matrix metalloproteinase-9 (MMP-9) inhibition and MMP-9 gene deletion in experimental stroke. However, the cellular source of MMP-9 produced in the ischemic brain and the mechanistic basis of MMP-9-mediated brain injury require elucidation. In the present study, we used MMP-9-/- mice and chimeric knockouts lacking either MMP-9 in leukocytes or in resident brain cells to test the hypothesis that MMP-9 released from leukocytes recruited to the brain during postischemic reperfusion contributes to this injury phenotype. We also tested the hypothesis that MMP-9 promotes leukocyte recruitment to the ischemic brain and thus is proinflammatory. The extent of blood-brain barrier (BBB) breakdown, the neurological deficit, and the volume of infarction resulting from transient focal stroke were abrogated to a similar extent in MMP-9-/- mice and in chimeras lacking leukocytic MMP-9 but not in chimeras with MMP-9-containing leukocytes. Zymography and Western blot analysis from these chimeras confirmed that the elevated MMP-9 expression in the brain at 24 h of reperfusion is derived largely from leukocytes. MMP-9-/- mice exhibited a reduction in leukocyte-endothelial adherence and a reduction in the number of neutrophils plugging capillaries and infiltrating the ischemic brain during reperfusion; microvessel immunopositivity for collagen IV was also preserved in these animals. These latter results document proinflammatory actions of MMP-9 in the ischemic brain. Overall, our findings implicate leukocytes, most likely neutrophils, as a key cellular source of MMP-9, which, in turn, promotes leukocyte recruitment, causes BBB breakdown secondary to microvascular basal lamina proteolysis, and ultimately contributes to neuronal injury after transient focal stroke.

Animals↗
PubMed2005

Postoperative radiation therapy for grade II and III intracranial ependymoma.

PURPOSE: To retrospectively determine the long-term outcome of intracranial ependymoma patients treated with surgery and postoperative radiation therapy. METHODS AND MATERIALS: Sixty patients were treated at our institution between 1964 and 2000. Forty patients had World Health Organization Grade II ependymoma, and 20 patients had Grade III ependymoma. The median patient age was 10.7 years. The majority of patients were male (55%), had infratentorial tumors (80%), and had subtotal resections (72%). Postoperative radiation therapy was delivered to all patients to a median total dose of 50.4 Gy. Craniospinal radiation therapy was used in the earlier era in only 12 patients (20%). RESULTS: The median follow-up of surviving patients was 12.5 years. The 5-year and 10-year disease-free survival rates for all patients were 58.4% and 49.5%, respectively. The 5-year and 10-year overall survival rates for all patients were 71.2% and 55.0%, respectively. Supratentorial tumor location was independently associated with a worse disease-free survival. Subtotal resection and supratentorial location predicted a worse overall survival, but this failed to reach statistical significance. No statistically significant effect on prognosis was observed with tumor grade, patient age, or radiation dose or volume. CONCLUSION: Our long-term follow-up indicates that half of ependymoma patients will have disease recurrences, indicating the need for more effective treatments.

Adolescent↗
PubMed2005

Identification and characterization of the peroxiredoxin gene family in chickens.

Peroxiredoxin (PRX) is a crucial antioxidant protein that protects against endogenously produced peroxides in prokaryotes to eukaryotes. To date, 6 different isoforms have been identified in mammals. In this study, we describe the first members of the PRX protein family to be characterized in Chicken. Through bioinformatics analysis, we observed that at least 4 different classes of PRX protein have been evolutionarily conserved in chickens. Furthermore, in vitro functional assays of the candidate chicken PRX proteins demonstrated that they had levels of antioxidant activity similar to those of the mammalian enzymes. The expression patterns of the PRX transcript in several chicken tissues were not tissue specific, suggesting that they might play an essential role as a housekeeping gene in all tissues to protect against oxidative damage. In conclusion, the sequences of the putative members of this functional gene family in chickens could be effectively retrieved in silico through bioinformatics analysis, and the functionality of their gene products evaluated by in vitro comparative assay.

Animals↗
PubMed2005

A set of testis-specific novel genes collected from a collection of Korean Native Chicken ESTs.

We report a set of testis-specific novel genes by comparing the The Institute for Genomic Research (TIGR) chicken gene index with the 13,132 expressed sequence tag (EST) collection from Korean Native Chicken (KNC). A total of 553 novel transcripts have resulted after comparison of our EST contigs and singlets against the chicken gene index and chicken genome sequences. Interestingly, 76% of the new genes were from testis-specific EST contigs or singlet and analysis of exon/intron structure showed that a significant number of the contigs have intronless coding regions. A large portion of the testis-specific transcripts have intronless coding region indicating that the testis-specific expression pattern is related to a group of single exon genes in the chicken. The chicken EST data that are described in this paper have been submitted to the NCBI dbEST under accession numbers CO759017-CO764274, CO765331-CO768903 and CO769672-CO773972.

Animals↗
PubMed2004

Hand somatosensory cortex activity following selective dorsal rhizotomy: report of three cases with fMRI.

INTRODUCTION: Selective dorsal rhizotomy (SDR) is an effective treatment for lower extremity spasticity in cerebral palsy. Cortical organization in sensory cortex may be abnormal in cerebral palsy, and deafferentation is known to lead to cortical reorganization in many situations. METHODS: We used functional magnetic resonance imaging (fMRI) of hand sensory stimulation to determine if the partial deafferentation of the lower extremity sensory system, associated with SDR, led to any alterations in the cortical somatosensory representation for the upper limbs. Three patients with spastic diplegia were studied with blood oxygen level-dependent (BOLD)-fMRI before and after SDR. fMRI during tactile stimulation of the digits of the right hand was used to map hand somatosensory cortex. Comparison of the cortical maps devoted to the hand before and after SDR assessed for cortical reorganization following partial deafferentation of the lower extremity. RESULTS: In the one patient with upper extremity involvement, the hand sensory representation was markedly enhanced following SDR. In the other two patients, a normal pattern, but with diminished activity, was seen compared with preoperative findings. SDR for lower limb spastic diplegia does not lead to extensive reorganization of cortex dedicated to the representation of the upper limb. An essentially normal pattern of activation was seen both before and after SDR. CONCLUSION: The relief of attention demands associated with spasticity may explain the modulation in intensity seen after SDR in the patients who exhibited no upper extremity involvement despite lower limb spasticity.

Adolescent↗
PubMed2004

Spatial filters based on independent component analysis for magnetic noise reduction in the magnetocardiogram.

A spatial filter design method to reduce magnetic noise in the magnetocardiogram (MCG) is introduced. Based on the facts that external magnetic noise appearing on multichannel MCG sensors is independent of the cardiac signals and that there is strong spatial correlation among the channels, the independent component analysis (ICA) method was applied to extract the noise components from the measured MCG signals. After extraction of the noise components in a given time period using ICA, a spatial filter was made to reduce the noise components in subsequently acquired MCG signals. In experimental studies of nine healthy volunteers, the spatial filters improved the signal-to-noise ratio of the MCG signals by about 500% on average. This spatial filtering method can be used for measurements of MCG signals in a magnetically noisy environment.

Artifacts↗
PubMed2004

Can diabetic neuropathy be prevented?

The incidence of diabetes and its complication have rapidly increased. Decreased quality of life and increased mortality are the major problems of people with diabetes. These problems are mainly caused by chronic complications. The incidence of diabetic neuropathy, which is one of these chronic complications, approaches 50% in most diabetic patients. The intensive metabolic management alone cannot completely prevent the development and progression of diabetic complications. Therefore, blocking and management of pathogenic mechanism of complication are required. Pathogenesis of diabetic neuropathy has multifactorial causes. Diabetic neuropathy is thought to occur both from direct hyperglycemia-induced damage to the nerve parenchyma and from neuronal ischemia brought about indirectly by hyperglycemia-induced decreases in neurovascular flow. The effects of hyperglycemia get converted to neuronal dysfunction via at least three secondary biochemical pathways: the polyol pathway, non-enzymatic glycation of proteins, oxidative stress and protein kinase C, and the interactions between them. Because of these interactions, interference with one of these biochemical pathways could either worsen or attenuate the effects of the others. So, the use of therapeutic intervention of these pathways is inevitable and valid to prevent the progression of diabetic neuropathy. As yet, a satisfactory and fundamental, preventive, and therapeutic method is not available with us to prevent progression. So, we will introduce the earlier diagnostic methods of diabetic neuropathy and will discuss the advantages and limitations of each method.

Diabetic Neuropathies↗
PubMed2004

Cerebrovascular inflammation after brief episodic hypoxia: modulation by neuronal and endothelial nitric oxide synthase.

Obstructive sleep apnea, apnea of prematurity, and sudden infant death syndrome are associated with a high risk of morbidity and mortality secondary to the neuronal and cerebrovascular consequences of the associated intermittent hypoxia. We hypothesized that episodic hypoxia (EH) promotes inflammation in the cerebral microcirculation and that nitric oxide (NO) produced by the endothelial and neuronal isoforms of NO synthase (eNOS and nNOS, respectively) modulates this response. Anesthetized and ventilated Swiss-Webster ND4 mice, wild-type mice, and NO synthase knockout mice were subjected to a 1-h period of EH (twelve 30-s periods of hypoxia every 5 min). Four, 24, or 48 h later, mice were reanesthetized for imaging of leukocyte dynamics in the cortical venular microcirculation by epifluorescence videomicroscopy through closed cranial windows. In Swiss-Webster ND4 mice, leukocyte adherence increased 2.1-fold at 4 h, 3.4-fold at 24 h, and 1.8-fold at 48 h relative to time-matched, normoxic controls; there was no evidence of delayed hippocampal CA1 pyramidal cell death. A similar response was noted in wild-type mice. However, in eNOS knockouts, leukocyte-endothelial cell adherence was elevated to 4.4-fold over baseline 24 h after EH, and a significant fraction of these animals showed evidence of delayed CA1 cell death. Conversely, in nNOS knockouts, no increase in adherence was noted at 24 h and CA1 viability remained unaffected. We conclude that NO derived from nNOS promotes an inflammatory response in the cerebrovascular microcirculation after short-term EH and that NO produced by eNOS blunts the extent of this response and exerts neuroprotective effects.

Animals↗
PubMed2004

Delayed hemolytic transfusion reaction due to anti-Fyb caused by a primary immune response: a case study and a review of the literature.

Delayed hemolytic transfusion reactions (DHTRs) usually occur between 3 and 14 days posttransfusion as a result of a secondary immune response, with a drop in Hb level, fever, jaundice, or hemoglobinuria. DHTRs caused by a primary immune response are particularly rare events, and only a few reports have been known. In this report, we describe an unusual case of a DHTR caused by anti-Fyb in a 42-year-old man, who had no prior history of transfusion. Although it seems to be a rare phenomenon, we suggest that DHTRs by a primary immune response may be considered even in the case of the patient who had typical evidence of hemolysis but who had no previous transfusion history.

Adult↗
PubMed2003

A critical analysis of 'normal' radionucleotide shuntograms in patients subsequently requiring surgery.

BACKGROUND: Shuntograms are performed when patients present with symptoms suggestive of, but inconclusive for, shunt malfunction, without confirmatory radiological evidence. METHODS: Shuntograms over the past 3.5 years were reviewed. Patient records were reviewed for revision in proximity to a negative (normal) study. RESULTS: One hundred and fifteen out of 149 tests were negative. Thirty-four surgeries (in 31 patients) occurred subsequent to a negative shuntogram. In 18 out of 34 revisions the shunt was functional: 13 surgeries were for overdrainage, 4 were for unrelated reasons with shunt function confirmed incidentally and 1 was an exploration for cognitive deterioration. In 16 cases (13 patients) the shunt was not functional: 12 had proximal catheter occlusion in which, on subsequent review, there was no ventricular reflux present and the remaining had distal malfunctions. CONCLUSIONS: The false negative rate for shuntograms was 16 out of 115 (14%) with proximal occlusion most common. This estimate of the predictive value of a normal flow study may influence the decision to revise a shunt.

Cerebrospinal Fluid Shunts↗
PubMed2003

Misidentification of Aeromonas veronii biovar sobria as Vibrio alginolyticus by the Vitek system.

AIMS: To find the cause of misidentification of aeromonads when using the Vitek system. METHODS AND RESULTS: Two Aeromonas veronii biovar sobria isolates were misidentified as Vibrio alginolyticus by the Vitek system. Both strains' identification was confirmed by biochemical testing, API 20E/20NE kits and/or 16S RFLP analysis. Thirty-one known Aeromonas species were tested by the Vitek system using 0.45 and 0.85% saline in the suspension medium. It was not clear whether low salinity causes misidentification of Aeromonas species more frequently. CONCLUSIONS: The specified reaction time may be inappropriately short for some critical biochemical tests of some strains. An ingenious reading strategy regarding incubation time is necessary to improve identification of Aeromonas species by the Vitek system. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report of misidentification of A. veronii biovar sobria as V. alginolyticus in the Vitek system.

Aeromonas↗
PubMed2002

Intrathecal baclofen withdrawal: a case report and review of the literature.

INTRODUCTION: Spasticity is an endpoint of a variety of neurologic disorders with upper motor neuron damage. There have been several studies demonstrating improvement in spasticity through administration of intrathecal baclofen. Withdrawal from oral baclofen has been well described. Intrathecal baclofen withdrawal has been less frequently reported. We present a case of withdrawal after intrathecal baclofen pump catheter failure. PATIENT: A 14-year-old boy presented with fevers, which were thought to be related to recent spine surgery and possible pneumonia. Eventual workup revealed evidence of intrathecal baclofen withdrawal owing to pump catheter failure. His fevers, with temperatures of up to 40 degrees C, and painful muscle spasms resolved and his clinical condition improved after pump exploration and resumption of intrathecal delivery. CONCLUSIONS: Intrathecal baclofen withdrawal can be life threatening. Prompt recognition and restoration of an adequate intrathecal baclofen dose is essential for recovery.

Adolescent↗