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D H Choi

Publications and source records attributed to D H Choi.

35 records · Page 2Linked to original sources
PubMed2000

Serologic and histopathologic study of Chlamydia pneumoniae infection in atherosclerosis: a possible pathogenetic mechanism of atherosclerosis induced by Chlamydia pneumoniae.

Chronic infection and inflammation have recently been implicated as important etiologic agents for atherosclerosis in general and, in particular, ischemic heart disease. Several agents have been suggested as possible candidates for the chronic inflammation including cytomegalovirus, Helicobacter pylori and Chlamydia pneumoniae. We hypothesized that a vascular infection with C. pneumoniae may induce a chronic inflammatory reaction in the host vascular tissue and activated inflammatory cells may express inflammatory mediators such as cyclooxygenase-2 (COX-2) and matrix metalloproteinases (MMPs). At first, we evaluated the relationship between C. pneumoniae infection and atherosclerosis indirectly by serologic study, and then, to confirm our hypothesis, we performed an immunohistochemical study of atherosclerotic plaques. The seropositive rate of anti-Chlamydia pneumoniae IgG was higher in the disease group (Group I, 59.8%, n = 254) than in the negative control group (Group III, 47.4%, n = 97) (p = 0.041), but the anti-Chlamydia pneumoniae IgA was not different in seropositivity between the two groups (Group I, 64.6%; Group III, 57.7%). The simultaneous seropositive rates of both IgG and IgA were 56.7% in Group I and 43.3% in Group III (p = 0.033). In subgroups without the conventional risk factors of atherosclerosis, these findings were more prominent. Furthermore, we performed immunohistochemical staining on the atherosclerotic aortic tissues obtained from patients that were seropositive to C. pneumoniae (n = 5), by using antibodies to C. pneumoniae, COX-2, and MMP-9. The immunoreactivity for COX-2 and MMP-9 increased in the atherosclerotic plaques itself, predominantly in the surrounding area of immunoreactive C. pneumoniae. These findings support our hypothesis and C. pneumoniae may participate in a pathogenetic mechanism for atherogenesis or progression of atherosclerosis. The present study may open a promising perspective concerning future therapeutic trials of chronic inflammation related atherogenesis under pathophysiological conditions.

Aged↗
PubMed1999

Characterization of antimicrobial agents extracted from Asterina pectinifera.

The extracts from the starfish Asterina pectinifera obtained using various organic solvents and distilled water were tested for their antimicrobial activities against fungi and yeasts. The methanol and water extracts were found to be the most active and Aspergillus spp. and Cryptococcus neoformans proved to be sensitive species. The extracts are polar, stable to a wide range of pH and a high temperature, and possess a very distinctive UV spectrum. The colour reactions for functional groups of antimicrobial substances indicate the presence of some distinctive chemical properties common to steroidal oligoglycosides which results suggest that the antimicrobial activity is due to structures common to steroidal oligoglycosides.

Animals↗
PubMed1999

Growth-inhibiting effects of Coptis japonica root-derived isoquinoline alkaloids on human intestinal bacteria.

The growth-inhibiting activity of Coptis japonica (Makino) root-derived materials toward eight human intestinal bacteria was examined using an impregnated paper disk method and compared to that of four commercially available isoquinoline alkaloids [berberine sulfate (BS), berberine iodide (BI), palmatine chloride (PC), and palmatine sulfate(PS)], as well as that of Thea sinensis leaf-derived epigallocatechin gallate (EGCG). The biologically active constituents of the Coptis extract were characterized as the isoquinoline alkaloids berberine chloride (BC), palmatine iodide (PI), and coptisine chloride (CC) by spectral analysis. The growth responses varied with both chemical and bacterial strain used. In a test using 500 microg/disk, BC and PI produced a clear inhibitory effect against Bifidobacterium longum, Bifidobacterium bifidum, Clostridium perfringens, and Clostridium paraputrificum, whereas weak or no inhibition was observed in Bifidobacterium adolescentis, Lactobacillus acidophilus, Lactobacillus casei, and Escherichia coli. At 1000 microg/ disk, CC revealed weak or no growth inhibition toward all test bacteria, whereas EGCG exhibited weak growth inhibition against only C. perfringens and C. paraputrificum. Among various isoquinoline alkaloids, BC exhibited more potent inhibitory activity toward C. perfringens than BI and BS, whereas the inhibitory effect was more pronounced in PI compared to PC and PS. The Coptis root-derived materials did not promote growth of B. longum and C. perfringens.

Alkaloids↗
PubMed1998

Inhibition of wound-induced expression of transforming growth factor-beta 1 mRNA by its antisense oligonucleotides.

Transforming growth factor-beta 1 (TGF-beta 1) is a member of a gene superfamily that regulates proliferation, differentiation and other functions in many cell types. To gain insight into the role of TGF-beta 1 in wound repair, we have analysed the ability of an antisense TGF-beta 1 oligodeoxynucleotides (ODN) to specifically inhibit wound-induced expression of TGF-beta 1 mRNA in the mouse skin. Although injury induced the expression of TGF-beta 1 mRNA at the wound sites, expression of TGF-beta 2-or TGF-beta 3-mRNA was not detected. In comparison to the 24 h following injury, higher levels of TGF-beta 1 mRNA expression were observed in the wound sites after 72 h. Northern blotting and in situ hybridisation analysis showed that wound sites treated with antisense TGF-beta 1 ODN exhibited no detectable levels of TGF-beta 1 mRNA after injury, whereas the sites treated with sense TGF-beta 1 ODN possessed significant amounts of its mRNA. Our results demonstrated that antisense TGF-beta 1 ODN inhibited the wound-induced expression of TGF-beta 1 mRNA in vivo.

Animals↗
PubMed1997

Radiation therapy results for patients undergoing inappropriate surgery in the presence of invasive cervical carcinoma.

Total vaginal or abdominal hysterectomy was considered an inadequate treatment method for invasive uterine cervix cancer. Usually the procedure was inadvertently performed on patients who were thought preoperatively to have benign or premalignant conditions. Between 1985 and 1993, 64 patients undergoing hysterectomy in the presence of invasive cervical cancer were treated with external radiation therapy and/or intracavitary radiotherapy. Preoperative diagnoses were carcinoma in situ (36), severe dysplasia (2), and early invasive cancer (14), and others were benign disease. Overall 5-year survival and relapse-free survival rates were 75.8 and 77.5%, respectively. For patients in retrospective stage IA, IB, and IIB (gross residual after surgery), overall 5-year survival rates were 90.9, 88.8, and 27.9%, respectively. Thirteen patients developed treatment failure; most of them (10/13) were patients with gross residual disease. Patients with early invasive cervical cancer (stage IA) had no treatment-related failure. Prognostic factors affecting survival by univariate analysis were retrospective stage (P = 0.0000) and preoperative diagnosis (P = 0.0021). Tumor histology was marginally significant factor (P = 0.0938). By multivariate analysis, only retrospective stage was significant prognostic factor (P = 0.0001). Adjuvant radiotherapy appears to be an effective treatment method for patients with presumed stage IA and IB after inadvertent hysterectomy. Survival for patients with gross disease remaining after inappropriate hysterectomy is poor. So, early cancer detection and proper management with precise pretreatment staging is necessary to avoid inadherent hysterectomy, especially in cases of gross residual disease.

Adult↗
PubMed1997

Real-time neural network based camera localization and its extension to mobile robot control.

The feasibility of using neural networks for camera localization and mobile robot control is investigated here. This approach has the advantages of eliminating the laborious and error-prone process of imaging system modeling and calibration procedures. Basically, two different approaches of using neural networks are introduced of which one is a hybrid approach combining neural networks and the pinhole-based analytic solution while the other is purely neural network based. These techniques have been tested and compared through both simulation and real-time experiments and are shown to yield more precise localization than analytic approaches. Furthermore, this neural localization method is also shown to be directly applicable to the navigation control of an experimental mobile robot along the hallway purely guided by a dark wall strip. It also facilitates multi-sensor fusion through the use of multiple sensors of different types for control due to the network's capability of learning without models.

Algorithms↗
PubMed1995

Effects of PEEP on acinar gas transfer in healthy and lung-injured dogs.

We measured cardiorespiratory variables and 133xenon washout from a nonperfused lung region (XeW) in six anesthetized/paralyzed dogs, mechanically ventilated with 60% O2 at different positive end-expiratory pressures (PEEP). XeW in this technique represents directly measured acinar gas transfer (3). Measurements were repeated after induction of lung injury by lavaging the lungs 11 to 13 times with 600 ml saline. In control dogs, lung compliance (CL), alveolar ventilation (Valv), and XeW all decreased with increasing PEEP from 0 to 25 cm H2O (p < 0.05), while lung resistance (RL) did not change. After lavage, CL, Valv, and XeW below 15 cm H2O PEEP were all less than control values (p < 0.05), while RL was higher than control values. As PEEP increased from 0 to 20 cm H2O, Valv and XeW increased, but CL did not change; RL decreased only from 0 to 5 cm H2O. At 20 cm H2O PEEP, Valv and CL were not different from control values (p > 0.05), and XeW was higher than control values (p < 0.05). At estimated alveolar volumes above 400 ml, values for XeW before and after lavage were similar. We conclude that, during severe lung injury: (1) increasing PEEP to moderate levels will increase acinar gas transfer but, after a certain lung volume is reached, further increases in PEEP will have effects similar to the healthy condition; (2) overall mechanical properties of the lung do not reflect the responses to PEEP of the lung periphery.

Animals↗
PubMed1993

Possible roles of LFA-1 and Fc gamma receptors on the functional immaturities of cord blood polymorphonuclear leukocytes.

The functional immaturity of PMNs is one of the major causes of overwhelming sepsis in newborns. In this study, we observed functions and surface markers of PMNs to investigate what causes the functional immaturity of PMNs in newborns. As results, the percentage of EA rosette forming PMNs (58.5 +/- 15.5%) and the chemotactic movement (0.14 +/- 0.09 mm) of cord blood PMNs were significantly lower than those of adult peripheral blood PMNs (70.8 +/- 9.9%, 0.60 +/- 0.34 mm). Cord blood PMNs showed decreased glass adherence and ADCC activity. The expression of Fc gamma RII or Fc gamma RIII was a little lower than those of adult peripheral blood PMNs, but the expression of Fc gamma RI (43.1 +/- 26.8%) was significantly higher than that of adult peripheral blood PMNs (3.2 +/- 1.8%). There was a significant difference in LFA-1 expression between EA rosette forming PMNs (92.9 +/- 9.1%) and EA rosette non-forming PMNs (25.6 +/- 22.6%). From these results, it is assumed that neonatal PMNs may consist of heterogeneous populations. And the relatively high percentage of EA rosette non-forming PMNs which express a low level of LFA-1 may be responsible for the functional immaturity of cord blood PMNs.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1992

Cell-mediated immunity in cervical intraepithelial neoplasia.

Various immune parameters, i.e., peripheral T and B cell distribution, T cell subpopulation, interleukin 2 (IL-2) activity and in vitro lymphocyte responses to phytohemagglutinin (PHA) and concanavalin A (Con A), were investigated in 24 pretreated patients with cervical intraepithelial neoplasia (CIN) and in 35 normal controls. Of the measured parameters, lymphocyte response to PHA was significantly lower in the CIN than control group (P less than 0.05). The values of all other measured parameters were similar in both groups.

B-Lymphocytes↗
PubMed1992

Isolation and partial characterization of cysteine proteinase from sparganum.

A proteolytic enzyme was purified from the tissue extract of spargana (plerocercoids of Spirometra erinacei) by DEAE-Trisacryl M ion exchange chromatography and thiopropyl-sepharose affinity chromatography resulted in a 21-fold purification. The proteinase activity was assayed with a synthetic fluorescent substrate, carbobenzoxy-phenylalanyl-7-amino-4-trifluoromethyl-coumarin. SDS-polyacrylamide gel electrophoresis of the purified materials revealed a single 28,000 dalton band. Inhibitor profiles of the band indicated that it belonged to cysteine endopeptidases. It exhibited identical pH curves with optimum at pH 5.5, and 50% activity from pH 4.7 to 8. It could completely degrade collagen chains to three identical products. It also showed some activity on hemoglobin. Furthermore, the band on immunoblots was reactive to the sera of sparganosis patients. These results suggest that the proteolytic enzyme belongs to cysteine proteinase which plays a role in the tissue penetration. Also it may be used as the antigen for diagnosis of active sparganosis.

Animals↗
PubMed1991

Role of induction chemotherapy in invasive cervical cancer.

The 386 cases of invasive cervical carcinoma treated with radiotherapy alone were statistically analyzed to delineate the high risk factors (HRFs) associated with a significantly high treatment failure rate; they were (1) stages III-IV, (2) lesion greater than or equal to 4.0 cm, (3) small cell carcinoma or adenocarcinoma, (4) stages I-II with lesion greater than or equal to 4.0 cm, and (5) lymphographic evidence of nodal metastasis. Then, chemoradiotherapy (induction chemotherapy plus subsequent radiotherapy) was instituted to 113 invasive cervical carcinoma patients with at least one such HRF. Each patient received two to three cycles of induction chemotherapy at about 3-week intervals. For squamous cell carcinoma, cisplatin, 100 mg/m2 iv, was followed immediately by 5-fluorouracil, 1000 mg/m2, as a 24-hr iv infusion x 5 days. For adenocarcinoma, cisplatin, 70 mg/m2 iv, on Day 1 was followed by cytoxan, 250 mg/m2, on Day 2, and adriamycin, 45 mg/m2, on Day 3. Five-year survival of these patients according to each HRF, in the above order, was 69.1, 67.2, 68.1, 78.3, and 79.5% after chemoradiotherapy, all significantly higher than 57.4, 53.0, 54.5, 48.0, and 48.8% by radiotherapy alone. Drug toxicities such as leukopenia, hepatotoxicity, nephrotoxicity, and hypomagnesemia were seen in 46.5, 53.2, 47.1, and 55.4% of all cycles, respectively. The toxicities altered drug schedule in 191 (61.2%) ongoing induction chemotherapy cycles. Our cisplatin-based induction chemotherapy is considered an effective preradiotherapy adjunct that can reduce treatment failure in HRF-associated invasive cervical carcinoma.

Adenocarcinoma↗
PubMed1991

Pregnancy after in vitro fertilization of human follicular oocytes collected from nonstimulated cycles, their culture in vitro and their transfer in a donor oocyte program.

This study describes the results with immature human follicular oocytes harvested from unstimulated ovaries, matured in vitro, fertilized, and transferred to an agonadal recipient. Two hundred seventy immature oocytes were aspirated from 23 ovaries removed for various gynecological indications from August 1988 to October 1989. The numbers of follicular oocytes collected from ovaries were compared by patients' ages and the stages of menstrual cycle. Immature oocytes in vitro were incubated with either mature follicular fluid (FF) or fetal cord serum (FCS). The maturation rate in the mature FF group was 55.8%, significantly higher than the 35.9% in the FCS group. In addition, mature FF group was shown to provide a significantly higher fertilization rate than the FCS group (81.0% versus 31.6%). More fertilized eggs developed into normal embryos in the nonstimulated cycle group than in stimulated cycles with routine treatment. Finally, five embryos were transferred to a woman with premature ovarian failure on day 18 of a steroid replacement cycle. She subsequently delivered healthy triplet girls. These results suggest that in vitro maturation of immature oocytes from unstimulated ovaries with mature follicular fluid could be used successfully in a donor oocyte program after in vitro fertilization.

Adult↗
PubMed1990

A case of laboratory-acquired murine typhus.

We encountered a 32-year-old Korean woman who developed murine typhus in a laboratory. She worked as a technician in a laboratory for rickettsial disease. Immunofluorescence test with rickettsial antigen (R. typhi) was positive at 1: 320 on admission and 1: 1280 after 4 weeks. A dose of 200 mg of doxycycline for 7 days proved to be effective for her condition.

Adult↗
PubMed1989

Regulation of acetyl CoA carboxylase mRNA in rat liver by high carbohydrate diet and insulin.

Acetyl CoA carboxylase contents in liver cytosol of rats refed a high carbohydrate diet or injected with insulin were measured by an immunoassay method in order to evaluate the effects of dietary carbohydrate and insulin treatment on the control in the amount of acetyl CoA carboxylase. Acetyl CoA carboxylase was purified 1,552 folds with a specific activity of 3.88 units/mg protein from livers of rats refed a high carbohydrate diet for 3 days following a 3-day fasting and the antibody was generated against the purified acetyl CoA carboxylase in a rabbit. Treatment of insulin (1.5 units/100g BW) and a high carbohydrate diet increased the amount of acetyl CoA carboxylase in liver cytosol by 3 times and 10 times, respectively, when compared to the enzyme content found in the control. The synthetic ratio of acetyl CoA carboxylase to total cytosolic proteins was 4 times higher in the insulin-treated group and 10 times higher in the high carbohydrated diet-treated group than the control group. The polysomal RNA contents in liver cytosols were 279% of the control in the insulin-treated group and 365% of the control in the high carbohydrate diet group. Also, the nascent chain of acetyl CoA carboxylase in polysome were 158% of the control in the insulin-treated group and 311% of the control in the high carbohydrate treated group. From these results, it is assumed that the increase of acetyl CoA carboxylase content in the rat liver cells by insulin treatment, or high carbohydrate diet refeeding has resulted from the increased polysomal acetyl CoA carboxylase mRNA, which is directly related to the biosynthesis of this enzyme.

Acetyl-CoA Carboxylase↗
PubMedDate not supplied

Bupivacaine-sparing effect of fentanyl in spinal anesthesia for cesarean delivery.

BACKGROUND AND OBJECTIVES: Visceral pain decreases in cesarean patients under spinal anesthesia when the dose of local anesthetic is increased. However, larger doses of local anesthetic are associated with higher sensory blocks. We hypothesized that the addition of fentanyl could reduce the dose of bupivacaine necessary to achieve adequate surgical anesthesia. METHODS: Two double-blinded, sequential, prospective studies were performed on 120 patients. In the preliminary study, the patients received 8, 10, or 12 mg of 0.5% hyperbaric bupivacaine intrathecally. In the second, main study, they received each bupivacaine dose with 10 microg of fentanyl. Each group consisted of 20 patients, and the groups were identified as B8, B10, B12, BF8, BF10, and BF12. Sensory and motor block, intraoperative pain defined by visual analogue scale (VAS), muscle relaxation, and side effects were assessed. We also measured the sensory and motor recovery and the onset of pain in the postanesthesia care unit (PACU). RESULTS: Maximal block level and incidence of high block (> or = T1) were higher in the 12-mg groups. There was intraoperative pain in 35% of the B8 patients and 20% of the B10 patients, but none in the B12 patients and all fentanyl groups. Incidences of other side effects were not different. The addition of fentanyl to bupivacaine significantly delayed the onset of postoperative pain and sensory recovery, but motor recovery time did not change with additional fentanyl. CONCLUSIONS: The optimal dose of hyperbaric bupivacaine to produce surgical anesthesia was 12 mg, which was accompanied by high sensory block. With the addition of 10 microg of fentanyl, the dose of bupivacaine could be reduced to 8 mg in spinal anesthesia for cesarean delivery.

Adjuvants, Anesthesia↗
PubMedDate not supplied

Effects of epidural injection on spinal block during combined spinal and epidural anesthesia for cesarean delivery.

BACKGROUND AND OBJECTIVES: Epidural injection has been known to enhance spinal anesthesia in combined spinal and epidural (CSE) anesthesia. Saline and local anesthetics have been reported to have a volume effect, elevating sensory level when supplementing a volume into the epidural space. We evaluated the effects of epidural injection when using the CSE technique for cesarean delivery. METHODS: Sixty-six parturients were allocated randomly into group C (control, n = 21), S (saline, n = 21), or B (bupivacaine, n = 24): epidural injections of 10 mL saline and 0.25% bupivacaine were given in groups S and B, respectively, 10 minutes after they received 8 mg of 0.5% hyperbaric bupivacaine intrathecally, and no injection was given in group C. The sensory level at 10 minutes, the maximal level and the time to reach it, and degree of motor block and muscle relaxation were compared. We also investigated intraoperative side effects and postoperative findings in the postanesthesia care unit. RESULTS: Epidural injection raised the sensory level significantly in groups S and B, but the maximal height of sensory block and degree of muscle relaxation did not differ among the groups. Fewer patients complained of intraoperative pain in group B than in the other groups (P <.001). CONCLUSIONS: We could not achieve satisfactory surgical analgesia with 8 mg of hyperbaric bupivacaine injected into the subarachnoid space using the needle-through-needle technique in cesarean deliveries. An epidural saline injection elevated the sensory level, which did not improve the spinal block, whereas an epidural injection of 10 mL of 0.25% bupivacaine enhanced the spinal block and sustained the block postoperatively.

Adult↗