Biomedical subjects

S M Choi

Publications and source records attributed to S M Choi.

16 recordsLinked to original sources

PubMed1998

Effectiveness of prenatal ultrasonography in detecting fetal anomalies and perinatal outcome of anomalous fetuses.

A retrospective study was performed over a 5-year period (1990-94) to evaluate the effectiveness of prenatal ultrasonography in terms of sensitivity, specificity, and predictive values in detecting fetal anomalies by comparing prenatal ultrasonic results with anomalies found in neonates and the perinatal outcome of anomalous fetuses. Minor congenital anomalies as listed and defined in the Eurocat Register were excluded. From a total of 5544 singletons, 4819 had at least one ultrasound scan (87%), of which 3004 at low risk and 1815 (38%) at high risk for anomalies had routine screening (RS) and indicated scanning (IS), respectively. A total of 136 fetuses were structurally abnormal (2.82%, RS and IS: 0.77% and 6.23%) and 200 major anomalies (RS and IS: 37 and 163) were recorded. The overall sensitivity of the ultrasound test was 78.7% (RS and IS: 34.8% and 87.6%, P < 0.01) for abnormal fetuses and 58.0% (RS and IS: 29.7% and 64.4%, P < 0.01) for anomalies. The overall specificity was 99.9% and the positive and negative predictive values were 97.3% and 99.4%, respectively; these values did not differ significantly between the two groups. The sensitivity of ultrasound for the detection of abnormal fetuses before 24 weeks was 22.8% (RS and IS: 13.0% and 24.8%) which was associated with a 61% (25/41) termination rate (RS and IS: 25% and 75.9%, P < 0.01) and a 24.4% (10/41) postnatal survival rate (RS and IS: 41.7% and 17.2%). The overall survival rate following pre- and postnatal correction of anomalies was 44.9% (RS and IS: 60.9% and 41.6%). For the detection of fetal anomalies anatomic ultrasound scanning is necessary during pregnancy, irrespective of pregnancy condition. Early detection of fetal anomalies could offer the option of pregnancy termination.

Abortion, Induced↗

PubMed1998

Interferon-alpha 2a, 13-cis-retinoic acid and radiotherapy for locally advanced carcinoma of the cervix: a pilot study.

UNLABELLED: Standard treatment with radiotherapy for locally advanced cancer of the uterine cervix has a response rate of less than 50%. Recently, concurrent chemotherapy with radiotherapy was introduced into the clinic but is value remains controversial. Interferon and retinoic acid possess antiproliferative, immunomodulatory, and antineoplastic activities. The combination of interferon and retinoic acid has significant activity in patients with squamous cell carcinoma. These compounds may also potentiate radiation cytotoxicity. This pilot study aimed to assess the clinical efficacy and tolerability of the combination of interferon-alpha 2a, 13-cis-retinoic acid and radiotherapy. Patients with locally advanced carcinoma of the cervix were treated at Severance Hospital, Yonsei University College of Medicine. Fifteen patients received the combination of interferon-alpha 2a, 13-cis-retinoic acid and radiotherapy. Twelve patients treated in previous years with comparable radiotherapy and concurrent chemotherapy served as historical controls. RESULTS: (1) Interferon-alpha 2a, 13-cis-retinoic acid and radiotherapy resulted in a 47% response rate (33% complete remissions) while patients treated with concurrent chemoradiotherapy had a 42% response rate (17% complete remissions) (2). Major toxicity of interferon-alpha 2a, 13-cis-retinoic acid and radiotherapy was fever (60%). There was no grade 3 or 4 toxicity. CONCLUSION: Systemic interferon-alpha 2a, 13-cis-retinoic acid and radiotherapy is an active and tolerable therapy for locally advanced cervical cancer. Randomized studies are required to define the role of bioradiotherapy in the treatment of advanced cervical cancer.

Adult↗

PubMed1997

Volumetric object reconstruction using the 3D-MRF model-based segmentation.

A number of segmentation algorithms have been developed, but those algorithms are not effective on volume reconstruction because they are limited to operating only on two-dimensional (2-D) images. In this paper, we propose the volumetric object reconstruction method using the three-dimensional Markov random field (3D-MRF) model-based segmentation. The 3D-MRF model is known to be one of efficient ways to model spatial contextual information. The method is compared with the 2-D region growing scheme under three types of interpolation. The results show that the proposed method is better in the aspect of image quality than other methods.

Algorithms↗

PubMed1996

Acute renal failure associated with Yersinia pseudotuberculosis infection in children.

We report 45 pediatric cases of Yersinia pseudotuberculosis infection confirmed by stool culture between May 1993 and June 1994. In 41 (91.1%) cases there had been contact with untreated well or mountain water. Y. pseudotuberculosis was also isolated from 4 samples of mountain spring water thought to be the sources of infection. During the course of the illness, acute renal failure (ARF) developed in 6 patients (13.6%). The age distribution of the ARF group (12.3 +/- 1.2 years) was significantly different from the non-ARF group (8.0 +/- 3.2 years). The serogroups of Y. pseudotuberculosis isolates from stool samples were 5 (n = 30) and 4 (n = 15). Isolates from the water samples were all serogroup 5. The main symptoms of both groups were fever, rash, abdominal pain, and vomiting. ARF developed between the 2nd and 14th days (mean 6 days) after the onset of fever, and oliguria (< 400 ml/m2 per day) developed in 3 patients (3/6, 50%) immediately after their fevers had subsided. ARF underwent a benign course, with complete recovery within a maximum of 4 weeks (mean 10.2 days), with 1 exceptional patient requiring hemodialysis. Renal biopsy showed evidence of tubulointerstitial nephritis. Y. pseudotuberculosis should be included as one of the causes of acute interstitial nephritis causing ARF in children, especially when the children have histories of drinking untreated water in endemic areas.

Acute Kidney Injury↗

PubMed1996

Effect of 13-cis-retinoic acid with neoadjuvant chemotherapy in patients with squamous cervical carcinoma.

Retinoids are strong inhibitors of epithelial cancer promotion and progression in experimental carcinogenesis. Recently, therapeutic trials of retinoids have demonstrated activities in cervical cancer and precancerous lesion of cervix. Our purpose was to determine whether additional administration of 13-cis-retinoic acid would improve the treatment effect of neoadjuvant chemotherapy in patients with squamous cell carcinoma of the cervix. From January 1994 through January 1995, 40 patients with invasive cervical cancer were enrolled in this prospective study and randomized into the two groups. Group 1 had neoadjuvant chemotherapy alone and group 2 had neoadjuvant chemotherapy plus 13-cis-retinoic acid (RA) at a dosage of 1 mg/kg/day for 1 month. Patients in group 1 and group 2 were similar with respect to age, parity, clinical stage, and histological subtype. Therapeutic responses were compared using Fisher's exact test, Mann-Whitney test, and Wilcoxon signed-rank test. RA increased the complete response rate of neoadjuvant chemotherapy from 0% in group 1 to 5% in group 2. However, a difference of overall clinical response rate between the two groups was not evident. The drug toxicities in group 1 and group 2 included anemia in 30.0% and 23.7%, leukopenia in 6.7% and 15.2%, and hepatotoxicity in 6.7% and 6.8%, respectively. More frequent incidence of mucocutaneous side effects was seen in group 2 than group 1, but these side effects were mild and reversible. The clinical response rate achieved in this trial indicates that the combination of 13-cis-retinoic acid and neoadjuvant chemotherapy, at least when used on the schedule reported herein, is not superior to treatment of neoadjuvant chemotherapy alone for patients with squamous cell carcinoma of the cervix. However, a single patient achieved a complete response on this therapy, and the impact of such a treatment on survival needs to be explored.

Adult↗

PubMed1996

Efficacy of hydrocolloid occlusive dressing technique in decubitus ulcer treatment: a comparative study.

The efficacy of hydrocolloid occlusive dressing technique was compared with that of the conventional wet-to-dry gauze dressing technique in decubitus ulcer of stage I and II. Forty-four patients were randomly divided into two treatment groups and each received treatment according to the two different protocols. As a result, 80.8% of the hydrocolloid occlusive dressing group (group 1) and 77.8% of the conventional wet-to-dry gauze dressing group (group 2) healed completely with no statistically significant difference between the two groups. However, the time required for complete healing was shorter in group 1 with 18.9 days compared to 24.3 days in group 2. Ulcer healing speed was also slightly faster in group 1 with 9.1 mm2/day compared to 7.9 mm2/day for group 2. Average treatment time spent by a medical staff member was significantly shorter in group 1 with 20.4 minutes/day compared to 2017 minutes/day in group 2. The hospital cost of the ulcer treatment was higher in group 2 compared to group 1 even without taking into consideration the medical personnel's labor cost. These results indicate that the hydrocolloid occlusive dressing technique offers less time consuming and less expensive method of treatment compared to the conventional technique in stage I and II decubitus ulcers.

Adult↗

PubMed1996

Effects of nitric oxide (NO) synthesis inhibition on antitumor responses during interleukin-2 (IL-2) treatment of mice.

OBJECTIVES: To evaluate if L-arginine: NO pathway is activated in tumor tissues during IL-2 therapy and to evaluate whether IL-2 induced NO synthesis represents an antitumor effector mechanism or an inhibitory factor against therapeutic effects of IL-2. METHODS: Four groups [untreated control, NG-monomethyl-L-arginine (MLA) therapy only, IL-2 therapy only, IL-2/MLA therapy groups] of BALB/c mice were injected intraperitoneally with 2 x 10(8) Meth A tumor cells on day 0. MLA was administered subcutaneously with Alzet continuous infusion pumps on day 2. IL-2 therapy (180,000 IU s.c. every 12h for 5 days) was started on day 3. NO production within ascites tumors was assessed by measuring nitrite concentrations in cultures of ascites cells harvested on day 8. Survival and the rate of body weight increment of the mice were measured to evaluate therapeutic responses. Daily urinary nitrate excretion was monitored to demonstrate the effectiveness of MLA in inhibiting NO synthesis. RESULTS: Nitrite production in supernatants of Meth A ascites cell cultures was 63 +/- 14 microM in IL-2 treated mice and 3.2 +/- 1.5 microM in untreated controls (p < 0.001). MLA prevented the IL-2 therapy induced increase in nitrite production. IL-2 therapy did not decrease the rate of body weight increment and marginally prolonged mean survival to 18.2 days, compared to 16.6 days in control mice (p = 0.255). MLA administration decreased the rate of body weight increment and prolonged mean survival of IL-2 treated mice (21.8 days, p = 0.001 versus IL-2 alone). Interestingly, the MLA treatment increased the rate of body weight increment and diminished the survival of control mice to 11.6 days (p = 0.003). MLA administration via Alzet continuous infusion pumps achieved approximately 60% suppression of urinary nitrate excretion by control mice. Subcutaneous IL-2 treatment strongly induced nitric oxide synthesis (up to 3.5 mumoles of urinary nitrate/ mouse/day). MLA also effectively suppressed IL-2 induced NO production. CONCLUSION: L-arginine: NO pathway can be activated in malignant ascites by IL-2 therapy and NO synthesis functions as an inhibitory mechanism against IL-2 induced anti-tumor effects.

Animals↗

PubMed1995

The subgingival microflora and gingival crevicular fluid cytokines in refractory periodontitis.

Refractory periodontitis manifests as a rapid, unrelenting, progressive loss of attachment despite the type and frequency of therapy. This study examined possible relationships between cytokine levels in gingival crevicular fluid (GCF), occurrence of specific periodontopathic microflora, and disease activity in patients with refractory periodontitis. Refractory periodontitis patients (7 male and 3 female) were selected on the basis of history and longitudinal clinical observations. In each patient, 2 teeth with pocket depths greater than 6 mm were selected and individual acrylic stents were fabricated with reference grooves for each site. The sites were examined at both baseline and 3 months later. The pattern and amount of alveolar bone resorption were assayed by quantitative digital subtraction radiography. Pocket depth and attachment loss were measured with a Florida Probe. The gingival index was measured at 4 sites around each sample tooth. Sites were divided into active sites (> or = 2.1 mm loss of attachment in 3 months) or inactive sites (< or = 2.0 mm loss of attachment in 3 months). The distribution and prevalence of the predominant microflora in active and inactive sites were compared using anaerobic culture and indirect immunofluorescence. Interleukin-1 beta, 2, 4, 6 and tumor necrosis factor-alpha (TNF-alpha) levels in gingival crevicular fluid (GCF) were quantified by ELISA. Prevotella intermedia and Eikenella corrodens significantly decreased in inactive sites but remained the same in active sites after 3 months. The active sites revealed significantly higher GCF levels of IL-2 and IL-6 than inactive sites at both baseline and at 3 months. IL-1 beta was also significantly greater in active sites than in inactive sites at 3 months. Alveolar bone loss in active sites correlated with increased GCF levels of IL-1 beta and IL-2. These results suggest that GCF levels of IL-1 beta, IL-2 and IL-6 and P. intermedia and E. corrodens in subgingival plaque may serve as possible indicators of disease activity in refractory periodontitis.

Adult↗

PubMed1989

Photoaffinity labeling of the mammalian dopamine transporter.

A high affinity (1-2 nM) radioiodinated, photoaffinity probe for the dopamine transporter, 1-(2-[bis-(4-fluorophenyl)-methoxylethyl)-4-(2-[4-azido-3- [125I]iodophenyl]ethyl)piperazine ([125I]FAPP) has been synthesized. Upon photolysis, [125I]FAPP incorporates into a striatal polypeptide of apparent Mr 62,000 as visualized by autoradiography following sodium dodecyl sulfate-PAGE. Photoincorporation of [125I]FAPP into the Mr 62,000 polypeptide was stereoselectively inhibited by various dopamine uptake agents with a potency order typical of the dopamine transporter. The glycoprotein nature of the apparent Mr 62,000 polypeptide was assessed following specific exo- and endoglycosidase treatment. The dopamine transporter appears to be associated with complex-type oligosaccharides as indexed by its susceptibility to neuraminidase but not alpha-mannosidase digestion. Complete N-linked deglycosylation of the neuronal dopamine transporter with the endoglycosidase, glycopeptidase-F, increased the electrophoretic mobility of the 62 kDa polypeptide to apparent Mr 48,000. [125I]FAPP should prove to be a useful probe for the molecular characterization of the dopamine uptake site in various tissues and under certain pathophysiological states.

Affinity Labels↗

PubMed1986

Antibodies to Actinobacillus actinomycetemcomitans in a Korean population.

Previous studies demonstrated that serum antibodies to Actinobacillus actinomycetemcomitans strain Y4 are significantly elevated in sera from localized juvenile periodontitis (LJP) and postlocalized juvenile periodontitis (P-LJP) patients compared to normal controls in United States populations. This study examined the age of subjects in relation to the antibody levels to A. actinomycetemcomitans in a Korean population. Seven groups were investigated including sera from newborns, infants, children, periodontally normal puberty and adult groups and LJP and P-LJP groups. Antibody levels were determined by an enzyme-linked immunosorbent assay (ELISA) to A. actinomycetemcomitans strain SNUDC 10-1 (serotype C) isolated from a Korean LJP patient. In the healthy non-LJP and non-P-LJP subjects, IgG levels decreased from the newborn group to the 5-month-old group and then gradually increased through the adult group. The IgM levels in these groups continuously increased from birth until a plateau was reached in the 2- to 6-year group. Serum IgA levels to strain SNUDC 10-1 were too low to be measured by this assay.

Actinobacillus↗

PubMed1986