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Biomedical subjects

I H Choi

Publications and source records attributed to I H Choi.

At least 73 records · Page 4Linked to original sources
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

The influence of temperature on muscle function in the fast swimming scup. I. Shortening velocity and muscle recruitment during swimming.

In this study, electromyography showed that scup can swim to a maximum speed of 80 cm s-1 with their red muscle whereas previous results showed that carp can swim to only 45 cm s-1. Our aim was to evaluate the adaptations that enable scup to swim nearly twice as fast as carp. Although we anticipated that, at their respective maximum speeds, the red muscle of scup would be shortening at twice the velocity (V) of carp muscle, we found that the values of V were the same (2.04 muscle lengths s-1). At any given swimming speed, V was higher in carp than in scup because carp had a larger sarcomere length excursion and higher tail-beat frequency. The smaller sarcomere excursion in scup is primarily associated with using a less undulatory style of swimming (i.e. with a smaller backbone curvature). This less undulatory style of swimming may be an important adaptation that not only reduces V but may also reduce drag. At their respective maximum speeds, however, the 28% lower sarcomere length excursion in scup is balanced by a 26% higher tail-beat frequency, giving an equal V to that of carp. Although the scup in this study were somewhat longer than the carp in the previous one (19.7 vs 13.4 cm), we believe that many of the observed differences are species-related rather than size-related. We also found that scup swam in a kinematically similar fashion at 10 degrees C and 20 degrees C. However, at 10 degrees C, the scup could swim to only 54 cm s-1 before recruiting their white muscle whereas, at 20 degrees C, they could swim to 80 cm s-1. The difference in speed of initial white muscle recruitment, as well as information on muscle mechanics, suggests that the scup compress their recruitment order into a narrow speed range at low temperatures, thereby recruiting more muscle fibres. Quantitative analysis of red muscle electromyograms in this paper supports this hypothesis.

Animals↗
PubMed1992

The influence of temperature on muscle function in the fast swimming scup. II. The mechanics of red muscle.

To understand better how scup can swim twice as fast as carp with its red muscle, we measured the mechanical properties of red muscle bundles in scup. The values of the mean maximum velocity of shortening (Vmax) at 10 degrees C (3.32 muscle lengths s-1) and at 20 degrees C (5.55 muscle lengths s-1; Q10 = 1.69) were nearly the same as those in carp. Isometric force, however, was approximately 50% greater (183 kN m-2; Q10 = 1.08). The maximal power generation was correspondingly about 50% greater in scup than in carp (71 W kg-1 at 10 degrees C and 134 W kg-1 at 20 degrees C; Q10 = 1.88). The larger power output of its muscle may be important in the faster swimming of the scup. In addition, the fact that scup use a less undulatory style of swimming means that, when they are swimming twice as fast, their red muscle shortens at the same velocity (V) and with the same V/Vmax (0.37, i.e. where maximum power is generated) as that of carp. The importance of V/Vmax is further shown by the comparison of scup swimming at different temperatures. The 1.69-fold higher Vmax at 20 degrees C than at 10 degrees C enables scup to swim with a 1.67-fold faster V at 20 degrees C. Thus, at both 10 degrees C and 20 degrees C, red muscle is used only over the same narrow range of V/Vmax (0.17-0.37), where experiments on isolated muscle suggest that power and efficiency are maximal. Therefore, V/Vmax appears to be an important design constraint that limits the range of velocities over which muscle is used in vivo, both at different temperatures and in fast- and slow-locomoting species.

Animals↗
PubMed1992

Immunogenicity and protective efficacy of solubilized merozoite-enriched Theileria sergenti immunogens. I: Protection against homologous stabilate challenge.

Theileria sergenti were isolated from infected erythrocytes by hypotonic lysis, and soluble merozoite antigens were purified by sonication and differential centrifugation. The preparation contained 29, 34, 35 and 105 kD immuno-dominant poly-peptides. The soluble antigens (0.5 mg/ml) were prepared and fortified with Freund's adjuvant. Five month old naive Korean calves were subcutaneously inoculated with the preparation and a booster dose was administered 4 weeks later. Nine weeks after the booster dose, vaccinates and controls were challenged with a homologous stabilate (5.6 x 10(6) RBC/dose, 40% Parasitemia). All animals were monitored for hematocrit, total erythrocyte count, parasitemia and for the specific antibody by Western immunoblot (WB) and indirect immuno-fluorescent antibody (IFA) test. By 18 weeks after vaccination (6 weeks after the challenge), vaccinated cattle had an average IFA titer of 1:10,240 compared with 1:1,280 of the controls. The vaccinates showed negligible change in hematocrit and total RBC count whereas control animals showed significant (p less than 0.05) hematological changes and associated anemia. After vaccination and challenge, the antibody responses demonstrated that vaccination had induced significant production of antibody to the 29 and 35 kD polypeptides. The latter polypeptide was much more strongly recognized by the vaccinated animals, and thus it may be a potential candidate for the vaccine.

Animals↗
PubMed1992

Immunogenicity and protective efficacy of solubilized merozoite-enriched Theileria sergenti immunogens. II: Protection against natural exposure under field conditions.

A Theileria sergenti soluble merozoite preparation containing the 29, 34, 35 and 105 KD as the immunodominant polypeptides, was evaluated for efficacy, safety and protectivity in Holstein calves against virulent field tick challenge. The soluble antigens (100 mg/dose) were fortified with either complete or incomplete Freund's adjuvant. Twenty naive calves, aged one month, were subcutaneously inoculated with the preparation and a booster dose was administered 4 weeks later. Twenty additional calves served as controls. Five weeks after the booster dose, vaccinates and uninoculated controls were moved to a pasture, a heavily tick infested area in Cheju-do, Korea. The vaccinates showed negligible change in hematocrit and total RBC count whereas control animals showed significant (p < 0.05) hematological changes and associated anemia. Only 30% of vaccinates required chemotherapy after the experiment was terminated. All control animals required chemotherapy and 25% received blood transfusion. The highest percent parasitized erythrocytes in vaccinated cattle was 0.4% as compared with 3.6% among controls during the month of July. A significant difference (p < 0.05) was observed in the rate of body weight increase. Significant differences were also noted in serum albumin, aspartate aminotransferase, total protein and bilirubin. Significantly more vaccinated cattle maintained normal ranges of hematological and biochemical values as compared with the control group. It is suggested that soluble merozoite T. sergenti antigens may be potential vaccine candidates for developing a genetic vaccine in Korea.

Animals↗
PubMed1992

Prognostic factors in congenital dislocation of the hip treated with closed reduction. The importance of arthrographic evaluation.

We reviewed the clinical records, arthrograms, and roentgenograms of sixty-one children who had seventy-two congenitally dislocated hips in an effort to identify factors that can be used to predict the outcome of treatment. Only patients who had been followed clinically and roentgenographically for a minimum of two years after the initial closed reduction were included in the study. The mean age at the time of closed reduction was thirteen months (range, three to forty-one months). The mean age at the time of the most recent follow-up was six years (range, two to fifteen years). The mean duration of follow-up after the initial closed reduction was five years (range, two to thirteen years). There was no statistical difference between the good, fair, and poor-result groups with regard to sex, the age at the initial reduction, the traction station, the side of involvement, the initial acetabular index, the initial grade of displacement, the effect of adductor tenotomy, and several of the arthrographic measurements. The medialization ratio (the percentage of the horizontal radius of the cartilaginous femoral head that lay medial to the Perkins line), measured at the time of the reduction, was significantly different (p < 0.04) between the hips for which the result was good or fair and those for which the result was poor. The medialization ratio averaged 75 per cent in the hips for which the result was good, 66 per cent in those for which the result was fair, and 57 per cent in those for which the result was poor. Limbus shapes 5 through 8 were associated with avascular necrosis (p < 0.05) and a poor result (p < 0.03).

Acetabulum↗
PubMed1992

Changes in somatosensory-evoked potentials in limb lengthening. An experimental study on rabbits' tibiae.

To assess the influence of the rate and amount of distraction on the electrophysiologic function of the peripheral nerve during limb lengthening, somatosensory-evoked potential (SSEP) studies were performed on the hindlimbs of 96 rabbits. In Group I, the tibiae were lengthened 0.35 mm per day; in Group II, 0.7 mm per day; in Group III, 1.05 mm per day; and in Group IV, 1.4 mm per day. The studies were done preoperatively and then postoperatively, until six weeks in Group I, five weeks in Group II, four weeks in Group III, and three weeks in Group IV. As lengthening proceeded, the P1 (the first major positive peak) latency gradually increased, whereas the amplitude decreased. Significant amplitude changes were observed at six-weeks postsurgery in Group I, three weeks in Group II, two weeks in Group III, and one week in Group IV. Significant changes in P1 latency were observed at four weeks postsurgery in Group II, three weeks in Group III, and two weeks in Group IV. Greater percentage increases in tibial length corresponded to more marked changes in P1 latency and amplitude. The SSEP monitoring may serve as an effective tool for early detection of neurologic dysfunction during limb lengthening.

Animals↗
PubMed1991

In vitro effect of interleukin-2 on proliferative responses of peripheral blood T cells from leprosy patients.

Because of the important role played by interleukin-2(IL-2) in T cell growth and differentiation, we investigated the effect of exogenous IL-2 on the proliferative response of peripheral blood mononuclear cells(PBMCs) from 77 leprosy patients. The proliferative responses of PBMCs from lepromatous leprosy(LL) or borderline lepromatous leprosy(BL) patients to M. leprae were significantly lower(cpm 6,051 +/- 803 for LL type; 4,951 +/- 2,529 for BL type) than those from tuberculoid leprosy(TT) or borderline tuberculoid leprosy(BT) patients (28,853 +/- 28,916 for TT type; 15,884 +/- 334 for BT type). To investigate the effect of exogenous IL-2, purified IL-2 was added at the start of culture at 100 unit/ml. There was an apparent increase in 3H-thymidine incorporation of M. leprae-stimulated PBMCs(18,723 +/- 6,503) in the presence of IL-2 compared to the results without IL-2(6,051 +/- 803) in LL patients. Twenty nine out of 33 LL patients belonged to the responders to IL-2 and four patients were nonresponders. Therefore we conclude that the defective cell mediated immune response in LL patients may result from diminished production of IL-2, but we can not exclude the possibility of diminished expression of the IL-2 receptor. And we suggest that the immunologic heterogeneous response of an individual to M. leprae is important to the pathogenesis of clinical disease in the same LL patients.

Cells, Cultured↗
PubMed1990

Anesthesia influences the outcome from experimental spinal cord injury.

The effect of anesthesia upon the functional outcome after experimental spinal cord injury (SCI) was studied in 221 rats subjected to graded weight drop contusion in the thoracic cord. Neurologic function was assessed in a blinded fashion for one week after injury using a modification of the method of Tarlov. The post-mortem concentrations of serotonin and its metabolite were measured in injured and surrounding spinal tissues in a subset of animals in order to estimate the survival of descending long-tract axons. In initial studies using non-ventilated animals where body temperature was not controlled (n = 130), halothane anesthesia was associated with significantly better neurologic scores at all levels of injury (50, 100 and 250 g.cm) in comparison to pentobarbital. In a second experiment under these conditions (n = 53) the effect of halothane was observed after a 50 g.cm injury in comparison to both pentobarbital and nitrous oxide. Improved neurologic recovery was accompanied by the preservation of normal serotonin and metabolite concentrations in spinal tissue caudal to the site of injury. These values did not differ from those measured in sham-operated animals. Separate experiments (n = 12) revealed halothane's preservation of somatosensory-evoked responses during the early postinjury period in animals showing improved neurologic recovery. Subsequent experiments (n = 12) were performed to assess the effect of oxygen supplementation and the control of rectal temperature and a separate series of acute experiments (n = 14) examined arterial blood pressure responses to injury in halothane- and pentobarbital-anesthetized animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1990

Interleukin-1 beta production by monocytes from leprosy patients.

The cause responsible for the lack of an efficient cell-mediated immunity or a delayed type hypersensitivity to M. leprae in lepromatous patients is poorly understood. But the resistance to M. leprae infection in humans is likely mediated by the activated macrophages to present M. leprae antigen to T cells for cell-mediated immunity. Phenolic glycolipid-I (PGL-I) is a M. leprae-specific antigen and is supposed to play a significant role in the long lasting unresponsiveness in lepromatous leprosy. In this study, IL-1 activities were tested among leprosy patients to evaluate monocyte function and the role of IL-1 in the immunosuppression in leprosy. We found that peripheral blood mononuclear cells (PBMCs) from tuberculoid patients were strongly reactive to M. leprae (mean cpm; 28,853 +/- 28,916), but the proliferative responses of PBMCs from lepromatous patients (mean cpm; 6,051 +/- 803) were significantly lower. IL-1 concentration in culture supernatant of monocytes from lepromatous patients was similar to that from tuberculoid patients with stimulation of M. leprae (lepromatous: 1,014 +/- 637 pg/ml, tuberculoid: 1,012 +/- 167 pg/ml) or lipopolysaccharides (IPS) (lepromatous: 3,479 +/- 2,188 pg/ml, tuberculoid: 4,246 +/- 2,432 pg/ml). The IL-1 concentration is sera from lepromatous patients (42 +/- 30 pg/ml) tended to be higher than those from tuberculoid patients (28 +/- 69 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Bacterial↗
PubMed1990

Circulating immune complexes and cell-mediated immunity in patients with hepatitis B virus associated liver diseases.

The prevalence of circulating immune complexes (CIC), their role and their relationship to cell-mediated immunity in patients with hepatitis B virus associated liver disease are still controversial. This study was designed to investigate the prevalence of CIC and their relationship to viral markers, to subsets of peripheral blood T lymphocytes and to suppressor cell activity in patients with hepatitis B virus associated liver diseases. CIC were positive in 29.3% of 41 healthy HBsAg carriers, 37.8% of 88 patients with hepatitis B virus associated liver diseases, and 15% of 41 healthy subjects by the platelet aggregation test (PAT). The prevalence of CIC in patients with acute hepatitis (40.0%) and in those with cirrhosis (61.5%) was significantly higher than in normal controls (p less than 0.05, p less than 0.005 respectively). There was no correlation between the titer of CIC and serum HBsAg titer or the status of HBeAg, and no significant decrease in the peripheral blood lymphocyte CD4/CD8 ratio in healthy HBsAg carriers (1.39 +/- 0.31) and in patients with liver diseases (1.40 +/- 0.54) compared to the normal controls (1.48 +/- 0.31). Concanavalin A induced suppressor cell activity on IgG producing cells was impaired in healthy HBsAg carriers (34.9%) (p less than 0.005) and in patients with liver diseases (25.3%) (p less than 0.0001), and this change was prominent in patients with chronic active hepatitis and cirrhosis (p less than 0.0001). And there was a significant reverse correlation between concanavalin A induced suppressor cell activity on IgG-producing cells and the titer of CIC in PAT positive patients with hepatitis B virus associated liver diseases. In conclusion, it was suggested that defective suppressor cell function may lead to an increased B cell activation and such activity may account for the presence of CIC.

Acute Disease↗
PubMed1990

Amputation or limb-lengthening for partial or total absence of the fibula.

Thirty-two patients who had ablation of the foot by the Syme or Boyd technique for partial or total absence of the fibula, with subsequent fitting of a prosthesis, were compared with eleven patients who had lengthening of the lower limb by the Wagner method, to assess the long-term results of each procedure. The final results were evaluated on the basis of pain, limp, limb-length discrepancy, level of physical activity, and satisfaction of the patient. Of the thirty-two patients who had an amputation, twenty-eight (88 per cent) had a satisfactory result, compared with only six (55 per cent) of the eleven patients who had limb-lengthening. The amount of inequality between the lower limbs was classified as follows: Group I--the foot of the shorter extremity was at the distal third of the contralateral, normal limb, and the percentage of shortening was 15 per cent or less; Group II--the foot of the shorter extremity was at the level of the middle third of the contralateral, normal limb, and the percentage of shortening was between 16 and 25 per cent; and Group III--the foot of the shorter extremity was at the level of the proximal third of the contralateral, normal limb, and the percentage of shortening was greater than 26 per cent. Lengthening was best suited for patients in Group I who had stable hips, knees, and ankles and a plantigrade foot. Patients in Groups II and III were best served by ablation of the foot and fitting of a prosthesis.

Adolescent↗
PubMed1990

Sequelae and reconstruction after septic arthritis of the hip in infants.

We evaluated the residual deformity and late treatment of thirty-four hips of thirty-one children who had had septic arthritis when they were less than one year old. The hips were classified into four groups on the basis of radiographic changes. Type-I deformity (five hips) involved transient ischemia of the epiphysis, with or without mild coxa magna, and these hips did not need reconstruction. Type-II deformity (eleven hips) included deformity of the epiphysis, physis, and metaphysis, and these hips needed an operation to prevent subluxation; the goals of the operation included improvement in acetabular coverage, improvement in abductor efficiency by epiphyseodesis or transfer of the greater trochanter, and equalization of limb-length discrepancy by epiphyseodesis of the contralateral limb. Type-III deformity (five hips) involved malalignment of the femoral neck, with extreme anteversion or retroversion or with a pseudarthrosis of the femoral neck that necessitated a realignment osteotomy of the proximal part of the femur or bone-grafting of the pseudarthrosis. Type-IV deformity (thirteen hips) included destruction of the femoral head and neck, with persistence of only a remnant of the medial base of the femoral neck. In the hips that had a Type-IV deformity, the complex clinical problems, which included severe limb-length discrepancy and incompetent articulation of the hip, necessitated operations such as Pemberton osteotomy, trochanteric arthroplasty, arthrodesis, epiphyseodesis of the contralateral limb, and lengthening of the ipsilateral tibia. The functional result was satisfactory in all five hips that had a Type-I deformity, in seven of eleven that had a Type-II deformity, in three of four that had a Type-III deformity, and in only four of thirteen that had a Type-IV deformity.

Arthritis, Infectious↗
PubMed1987

HLA and leprosy in Koreans.

HLA antigens in 157 unrelated Koreans with leprosy have been identified and compared with 162 healthy Korean controls. The patient group consisted of 124 with lepromatous leprosy and 33 with tuberculoid leprosy. Although no significant differences were detected between the two patient groups, several antigens were found to be increased in the combined patient group compared to healthy controls. Two Class I antigens were increased: HLA-A11 (22% vs 12%) and Aw33 (27% vs 14%). Four Class II antigens were increased: HLA-DR1 (16% vs 7%), DR2 (39% vs 21%), DRw9 (14% vs 6%) and DQw1 (74% vs 55%). HLA-DR4 (28% vs 48%), DRw53 (46% vs 69%) and DQw3 (50% vs 75%) in contrast were significantly decreased in patients. Interaction of DR1, DR2, DRw9 and DQw1 as risk factors was analyzed. HLA-DR2 appeared to be the strongest risk factor. No evidence for synergy between DR1, DR2 and DRw9 was detected. DQw1 was not significantly increased in patients in the absence of DR1 and DR2, and thus it was not apparent in this study that DQw1 was an independent risk factor.

Disease Susceptibility↗
PubMed1986

The HLA system in the Korean population.

The frequencies of HLA-A, B, C, DR, and DQ antigens, HLA-D (HTC-defined) haplotypes, and the HLA-linked genetic markers glyoxalase I (GLO), factor B (Bf), C2 and C4 were studied in 162 healthy unrelated Koreans. Antigens A2, A24, A26, B44, B51, Bw62, B35, Cw1, Cw3, DR2, DR4, DRw6, DR7, and DRw8 were observed at frequencies of 15% or greater, and GLO-2, BfS, C4A*3, C2C, C4A*4, C4B*1, and C4B*2 were also frequently observed. The antigens A23, A25, B18, Bw42, Bw47, and B21 were not observed at all. HLA-DR4 was the most common class II antigen and was associated with a series of HLA-D-defined haplotypes including Dw4, Dw10, Dw13, and Dw15. The HLA-DRw6, DR2,Dw8, and DRw8 haplotypes were also found frequently. DR2 haplotypes were either Dw2 or Dw12, while all DRw8 haplotypes tested corresponded to the DB7 or Dw "8.3" specificity that has been described in other Oriental populations. Significant linkage disequilibrium was found between the alleles A2,Cw1; A30,B13; A30,Cw6; A30,DR7; Cw1,Bw22; Cw5,B12; Cw6,B13; Cw6,DR7; B7,DR1; B12,Dw6; B12,DR7; B12,Dw7; B13,DR7, B17,DR3; Bw22,C4B*6; DRw6,BfF; and C4A*4,C4B*2. A comparison of gene frequencies and commonly observed haplotypes between Koreans, Chinese, Japanese, and Caucasians showed that while Koreans share several characteristics in common with other Oriental populations, there are allelic frequencies and haplotypes in Koreans that are distinct.

Complement C2↗