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Biomedical subjects

M C Park

Publications and source records attributed to M C Park.

17 recordsLinked to original sources
PubMed2005

Post-interventional immunosuppressive treatment and vascular restenosis in Takayasu's arteritis.

OBJECTIVE: To investigate the outcome of vascular interventions and the effect of post-interventional immunosuppressive treatment on the occurrence of vascular restenosis in patients with Takayasu's arteritis (TA). METHODS: Forty-two patients with TA who had undergone vascular intervention and had serial angiographies before and after intervention were enrolled. The demographic and clinical data were collected at the time when the interventions were performed, and the intervention modalities and post-interventional medical treatments were evaluated. RESULTS: Sixty-three interventions were performed in 42 patients. Twenty (31.7%) interventions restenosed 24.0 +/- 21.9 months after intervention; the likelihood decreasing as time passed. Estimates of arterial patency after intervention were 90.1% at 1 yr, 75.5% at 2 yr, 68.4% at 3 yr, 61.6% at 5 yr and 49.3% at 10 yr. According to the log rank test, interventions that were performed during the stable stage of the disease (P = 0.039) and those that were followed by treatment with glucocorticoids and immunosuppressive agents (P = 0.044) were independent variables for the maintenance of arterial patency. Their hazard ratios were 0.30 and 0.41, respectively. CONCLUSION: Restenosis occurred in 31.7% of TA patients after intervention. A lower restenosis rate was observed when the vascular interventions were performed at the stable stage and when post-interventional immunosuppressive treatment was implemented.

Adolescent↗
PubMed2005

Serum cytokine profiles and their correlations with disease activity in Takayasu's arteritis.

OBJECTIVE: To investigate serum profiles of inflammatory cytokines in patients with Takayasu's arteritis (TA) and to determine their correlations with disease activity of TA. METHODS: Forty-nine patients with TA and 12 age- and sex-matched controls were studied. Blood samples were obtained and were divided into active and stable disease groups. Paired blood samples were available in 19 patients at the active stage before treatment and at the remitted stage after treatment. Serum tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-6, IL-12 and IL-18 levels were determined by enzyme-linked immunosorbent assay. RESULTS: Serum TNF-alpha, IL-6 and IL-18 levels of patients with TA were significantly higher than those of controls (P<0.05), but IFN-gamma and IL-12 levels were not. Serum IL-6 and IL-18 levels were significantly higher in the active disease group than in the stable disease group (P<0.05), but the levels of TNF-alpha were not different between the groups. In the 19 patients with paired samples, serum IL-18 levels at the remitted stage after treatment were significantly decreased compared with the active stage before treatment (P<0.001). The changes in IL-18 levels between active and remitted stages correlated well with changes in erythrocyte sedimentation rate (P<0.001). CONCLUSION: Serum IL-18 and IL-6 levels were elevated in patients with TA, especially in those with active disease. Serum IL-18 levels correlated well with disease activity of TA. These results suggest that IL-6 and IL-18 might contribute to the pathogenesis of TA and that IL-18 could be a useful marker for monitoring disease activity of TA.

Adult↗
PubMed2001

Consistent features in the forelimb representation of primary motor cortex in rhesus macaques.

The purpose of this study was to systematically map the forelimb area of primary motor cortex (M1) in rhesus macaques in an effort to investigate further the organization of motor output to distal and proximal muscles. We used stimulus-triggered averaging (StTAing) of electromyographic activity to map the cortical representation of 24 simultaneously recorded forelimb muscles. StTAs were obtained by applying 15 microA stimuli to M1 sites while the monkey performed a reach and prehension task. Motor output to body regions other than the forelimb (e.g., face, trunk, and hindlimb) was identified using repetitive intracortical microstimulation to evoke movements. Detailed, muscle-based maps of M1 revealed a central core of distal (wrist, digit, and intrinsic hand) muscle representation surrounded by a "horseshoe"-shaped zone of proximal (shoulder and elbow) muscle representation. The core distal and proximal zones were separated by a relatively large region representing combinations of both distal and proximal muscles. On the basis of its size and characteristics, we argue that this zone is not simply the result of stimulus-current spread, but rather a distinct zone within the forelimb representation containing cells that specify functional synergies of distal and proximal muscles. Electrode tracks extending medially from the medial arm of the proximal muscle representation evoked trunk and hindlimb responses. No distal or proximal muscle poststimulus effects were found in this region. These results argue against the existence of a second, major noncontiguous distal or proximal forelimb representation located medially within the macaque M1 representation.

Animals↗
PubMed2000

Chronic recording of EMG activity from large numbers of forelimb muscles in awake macaque monkeys.

Studies of the neural control of movement often require or benefit from long-term recording of EMG activity from large numbers of muscles involved in a particular motor task. While chronic recording of EMG activity has been described in a number of previous monkey studies, the number of muscles recorded has been somewhat limited and the implantation approach has been highly invasive procedures. This paper presents two EMG implant fabrication and surgical implantation methods that are suitable for use in monkeys, relatively non-traumatic and capable of simultaneous recording from 24 or more muscles.

Animals↗
PubMed1998

Induction of reproductive organ-preferential histone genes by wounding or methyl jasmonate.

A cDNA clone CaH2B, which is highly expressed in floral buds, was isolated from hot pepper plants (Capsicum annuum) by the mRNA differential display method. Sequence analysis of CaH2B revealed that the clone contains an open reading frame of 145 amino acid residues, which are 77% identical to a maize H2B histone. The CaH2B mRNA was barely detectable in roots, was more abundant in anthers than in seedlings, and was expressed highest in floral buds and fruits. An in situ analysis of CaH2B in floral buds indicated that the transcript is highly present in the pollen and petals. Northern analysis of CaH4, a pepper H4 histone cDNA, which was obtained during the expressed sequence tag (EST) analysis of anther tissues, showed that the expression pattern was very similar to that of CaH2B, although the expression level was slightly different. Both histone genes were examined for inducibility by wounding, methyl jasmonate (MJ), or phytohormones. CaH2B and CaH4 were induced by wounding, and maximally induced ca. 3 h after wound treatment both in vitro and in planta. Airborne MJ greatly induced the expression of the genes as well. The inducing effect by wounding was suppressed by MJ, suggesting that wounding and MJ might have different roles in signal transduction for the histone gene induction. Southern blot hybridization showed that both H2B and H4 genes are comprised of multigene families in the hot pepper.

Acetates↗
PubMed1996

Intravesical bacille Calmette-Guérin therapy for muscle invasive bladder cancer.

OBJECTIVES: This investigation attempted to determine whether the degree of fibronectin expression in the bladders of patients with invasive transitional cell carcinoma correlated with their clinical response to intravesical bacille Calmette-Guerin (BCG) therapy. METHODS: Following transurethral resection of all invasive disease, 13 patients with Stages T2-T4 bladder cancer were administered intravesical BCG (fo 6 weeks followed by monthly instillations). Fibronectin expression in the patients' resected tumors and normal mucosa was determined by immunohistochemical staining techniques. Minimum disease-free follow-up was 60 months. RESULTS: Only 1 of 13 patients had neither local nor systemic disease recurrence; 10 of 13 patients developed systemic disease and 7 patients died from metastases. Fibronectin expression was not correlated with the clinical response to BCG. CONCLUSIONS: Intravesical BCG therapy for the treatment of muscle invasive transitional cell carcinoma of the bladder is ineffective. Fibronectin expression in the bladder of patients with invasive disease is variable and does not correlate significantly with the clinical response to BCG therapy.

Administration, Intravesical↗
PubMed1993

Fibronectin expression on surgical specimens correlated with the response to intravesical bacillus Calmette-Guerin therapy.

Attachment of bacillus Calmette-Guerin (BCG) organisms to the bladder during intravesical therapy is thought to be mediated exclusively by the glycoprotein fibronectin, which is expressed variably on epithelial surfaces and on basement membranes. We examined the relationship between the degree of fibronectin expressed on surgical specimens obtained from 50 candidates for BCG therapy and the subsequent clinical response. Immunoperoxidase staining for fibronectin was performed on tumor, nonadjacent normal mucosa and basement membrane tissues, and the intensity of the staining was scored on a scale of 0 to 3+ (control 2+). In the absence of recurrence at quarterly surveillance cystoscopy, a course of Tice BCG therapy consisted of 6 weekly and 12 monthly instillations. Recurrence of noninvasive tumor prompted a second BCG course. Followup ranged from 24 to 66 months (median 40 months). Of the 50 patients (11 with carcinoma in situ) disease progression occurred in 9 (none with carcinoma in situ). Compared to the results for tumors or for basement membranes, the degree of fibronectin expression on normal mucosa was well correlated with the clinical response (r = 0.59, p < 0.001 by Kendall Tau B). Routine assessment of fibronectin expression on the normal mucosa associated with superficial bladder cancer may be useful for predicting the clinical response to BCG therapy.

Administration, Intravesical↗
PubMed1992

Primary non-Hodgkin's malignant lymphoma of the vulva--a case report.

A case of primary non-Hodgkin's malignant lymphoma of the vulva which occurred in a 68-year-old woman is presented. Non-Hodgkin's malignant lymphoma is infrequently involved in the female genital tract. Moreover, primary vulvar involvement of this tumor is very rare. To date only 6 cases have been reported in the literature. To our knowledge this is the first reported case of a non-Hodgkin's malignant lymphoma of the vulva in Korea.

Aged↗
PubMed1988

Isolation and characterization of a novel lipoprotein particle from human placental extracts.

While it is believed that placental tissue is very active in lipid metabolism, the nature of lipid containing particles secreted (if any) by this tissue is not known. Lipoprotein profile of human placental tissue was analysed by gel filtration, gel electrophoresis and electron microscopy. Our studies demonstrated the presence of lipoproteins with unusual compositions. A novel major lipoprotein (which eluted in the same position on plasma VLDL) was characterized. While this lipoprotein floated at density greater than 1.006 gr/ml and contained apo B (same as plasma VLDL) it differed from plasma VLDL in a) size, b) contining a significant amount of apo Al, and c) carried bulk of the cholesterol (80% in free form) and phospholipids. This study suggests that placental tissue might contain unique lipoproteins perhaps serving specific metabolic needs.

Cholesterol↗
PubMed1988

Lecithin:cholesterol acyltransferase in familial HDL deficiency (Tangier disease).

These studies were performed to investigate the relationship between the enzyme lecithin:cholesterol acyltransferase and plasma lipoproteins in Tangier disease, a condition characterized by a virtual absence of high-density lipoproteins (HDLs) and an accumulation of cholesteryl esters in peripheral tissues. Apolipoprotein A-I was nearly absent from the patient's plasma (1% of the normal levels were found). However, apolipoprotein A-I purified from the plasma of the Tangier disease patient, was found to activate both purified and the plasma enzyme. At lower apolipoprotein concentrations (up to 25 micrograms/ml), about twice the amount of Tangier apolipoprotein A-I was required to achieve a certain level of lecithin:cholesterol acyltransferase activity as compared with the activating potential of the normal apolipoprotein. Gel chromatography studies revealed that as in normal plasma, lecithin:cholesterol acyltransferase in Tangier plasma was associated with an HDL-size lipoprotein fraction. However, unlike in normal plasma, this lipoprotein complex (containing lecithin:cholesterol acyltransferase) was not removed from Tangier plasma by immunoaffinity chromatography utilizing immobilized anti-apolipoprotein A-I antibodies. Plasma incubation studies showed that free cholesterol was primarily supplied by LDL in normal plasma, whereas both LDL and VLDL donated the free cholesterol for lecithin:cholesterol acyltransferase reaction in Tangier plasma. The majority of the cholesteryl esters, generated during the incubation experiments, were transferred back to LDL in normal plasma, whereas in Tangier plasma both LDL and VLDL served as cholesteryl ester acceptors. The cholesteryl ester transfer from HDL to lower-density lipoproteins was lower in Tangier plasma as compared to this process in a normal control, suggesting that a minimal cholesteryl ester core may be required for the stability of HDL.

Apolipoprotein A-I↗
PubMed1988

Fecal protoporphyrin excretion in erythropoietic protoporphyria: effect of cholestyramine and bile acid feeding.

The effect of cholestyramine and bile acid feeding upon fecal, red blood cell, and plasma protoporphyrin levels was evaluated in a patient with erythropoietic protoporphyria and evidence of hepatic damage. After a basal period on a controlled diet, bile acids alone were administered (300-900 mg) daily for 9 days, followed by cholestyramine (12 g) plus bile acids (900 mg) daily for 7 days, and cholestyramine alone (12 g) daily for 6 days. There was no substantial change in either the red blood cell or plasma protoporphyrin concentrations during any treatment period. However, cholestyramine and cholestyramine combined with bile acids caused a threefold increase in fecal protoporphyrin excretion, whereas bile acids alone had no effect in this regard. After 1 yr of cholestyramine therapy, fecal excretion of protoporphyrin remained elevated with concurrent improvement in liver function tests and photosensitivity. This study indicates that cholestyramine but not bile acids can substantially increase protoporphyrin excretion and therefore may be capable of ameliorating the hepatotoxicity that may occur in selected patients with erythropoietic protoporphyria.

Bile Acids and Salts↗
PubMed1984

Effects of detergents on the lecithin:cholesterol acyltransferase reaction.

This paper describes the effect of an ionic (sodium dodecyl sulfate; SDS) and a nonionic detergent (Triton X-100) on the substrate and enzyme components of the lecithin: cholesterol acyltransferase (LCAT) reaction. When the enzyme sources (purified or partially purified) or the respective substrates [high-density lipoproteins (HDL) or proteoliposomes] were preincubated with detergents, a consistent trend in LCAT activity was only seen when partially purified LCAT was used as the enzyme source. This trend indicated an approximately 25% increase in enzyme activity over the control when 10(-4) M SDS and 2 X 10(-3)% Triton X-100 were present in the preincubation mixtures, respectively. Those observations suggested that, during the preincubations and subsequent assays, the enzyme (in the presence of detergents) was allowed to dissociate from the endogenous substrate and subsequently interact with the exogenous substrate molecules. Additional experiments utilizing molecular-sieve chromatography with whole plasma and partially purified enzyme also showed that dissociation of LCAT/lipoprotein complexes occurred in the presence of detergent. SDS was also shown to enhance the reaction of LCAT in whole plasma with anti-LCAT antibody in an enzyme-linked immunoassay system, indicating that the detergent treatment facilitated the exposure of additional antigenic sites, perhaps via dissociation of the enzyme from plasma lipoproteins.

Animals↗
PubMed1980

Chronic expanding hematomas. A clinicopathologic entity.

Chronic exapnding hematomas occur in many locations, often simulating neoplasms. All have the same structure with a central mass of blood, a wall of granulation tissue, and dense, fibrous tissue at the periphery. The self-perpetuating exapnding nature of the lesion appears to be due to the irritant effects of blood and its breakdown products, causing repeated exudation or bleeding from capillaries in the granulation tissue.

Abdominal Muscles↗