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Biomedical subjects

K Choi

Publications and source records attributed to K Choi.

At least 55 records · Page 3Linked to original sources
PubMed1996

Validation of questionnaire and bronchial hyperresponsiveness against respiratory physician assessment in the diagnosis of asthma.

BACKGROUND: The Tasmanian Asthma survey (TAS) and the International Study of Asthma and Allergies in Childhood (ISAAC) have used questionnaires to measure the prevalence of asthma in adults and children. We have investigated the validity of these questionnaires by comparing response to questionnaire with a physician assessment of asthma status in the past 12 months. METHODS: Ninety-three adults were given the TAS questionnaire to complete and 361 children were given the ISAAC questionnaire. Ninety-one adults and 168 children completed bronchial challenge with hypertonic saline. A consultation with a respiratory physician blinded to the results of the questionnaire and bronchial challenge was given to all subjects. RESULTS: In both adults and children, questionnaires showed high agreement with respiratory physician diagnosis with respect to asthma symptoms in the past 12 months. For the TAS questionnaire the positive and negative predictive values (95% confidence limits) for physician diagnosis for adults were 0.89 (0.68-0.98) and 0.94 (0. 86-0.98) respectively. The instrument was also sensitive 0.80 (0. 58-0.93) and highly specific 0.97 (0.90-0.99). For the ISAAC questionnaire the positive and negative predictive vales for physician diagnosis of asthma in children were 0.61 (0.50-0.71) and 0.94 (0.88-0.98) respectively. Sensitivity and specificity were 0.85 (0.73-0.93) and 0.81 (0.76-0.86) respectively. Compared to the physician diagnosis, the sensitivity of bronchial hyperresponsiveness (BHR) for asthma was low for adults 0.39 (0.21-0. 61) and children 0.54 (0.48-0.67) as were the positive predictive values: 0.55 (0.31-0.79) for adults and 0.64 (0.449-0.77) for children. A definition of asthma requiring both a positive questionnaire response and BHR was highly specific but not sensitive for adults 0.37 (0.20-0.59) or children 0.47 (0.35-0.60). CONCLUSIONS: Both the TAS and ISAAC questionnaires are valid instruments for the determination of asthma symptoms in the past 12 months.

Adolescent↗
PubMed1996

Intestinal perforation 14 years after abdominal irradiation and chemotherapy for Wilms tumor.

A 3-year-old girl underwent left nephrectomy and removal of a tumor thrombus from the inferior vena cava and right atrium in 1978 because of Wilms tumor. Her treatment consisted of tumor bed irradiation (4,000 cGy) and chemotherapy with actinomycin D, vincristine, and doxorubicin. The patient underwent laparotomy 2 months after completion of abdominal irradiation to relieve intestinal obstruction. Fourteen years later, she underwent another laparotomy because of an "acute abdomen" and was found to have perforation of the jejunum in the radiation field. Histopathological examination of resected intestine revealed evidence of severe chronic radiation enteritis, A diagnosis of chronic radiation enteritis should be considered in patients who had received abdominal irradiation and who manifest abdominal pain/vomiting even several years after irradiation.

Abdomen↗
PubMed1996

Purification and characterization of a fibrinolytic enzyme produced from Bacillus sp. strain CK 11-4 screened from Chungkook-Jang.

Bacillus sp. strain CK 11-4, which produces a strongly fibrinolytic enzyme, was screened from Chungkook-Jang, a traditional Korean fermented-soybean sauce. The fibrinolytic enzyme (CK) was purified from supernatant of Bacillus sp. strain CK 11-4 culture broth and showed thermophilic, hydrophilic, and strong fibrinolytic activity. The optimum temperature and pH were 70 degrees C and 10.5, respectively, and the molecular weight was 28,200 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The first 14 amino acids of the N-terminal sequence of CK are Ala-Gin-Thr-Val-Pro-Tyr-Gly-Ile-Pro-Leu-Ile-Lys-Ala-Asp. This sequence is identical to that of subtilisin Carlsberg and different from that of nattokinase, but CK showed a level of fibrinolytic activity that was about eight times higher than that of subtilisin Carlsberg. The amidolytic activity of CK increased about twofold at the initial state of the reaction when CK enzyme was added to a mixture of plasminogen and substrate (H-D-Val-Leu-Lys-pNA). A similar result was also obtained from fibrin plate analysis.

Amino Acid Sequence↗
PubMed1996

Hematopoietic and reproductive hazards of Korean electronic workers exposed to solvents containing 2-bromopropane.

OBJECTIVES: The purpose of this study was to describe hematopoietic and reproductive hazards of Korean electronic workers exposed to solvents containing 2-bromopropane. METHODS: Detailed medical and occupational histories were taken and thorough physical examinations with clinical laboratory tests were done for 33 workers (8 men and 25 women). Previous and present exposure was investigated in detail by industrial hygienists. RESULTS: Of the 25 female workers, 16 were shown to have secondary amenorrhea with high follicle-stimulating hormone levels, normal prolactin levels, and hot flashes. A total of eight workers with amenorrhea concurrently showed findings of pancytopenia. Among eight male workers, two showed azoospermia and another four showed some degree of oligospermia (normal > 20 million. ml-1) or reduced sperm motility (normal > 50%). The bone marrow effects and the testis or ovarian failure was shown to be the main health hazards in this workplace. Except for the cleaning solution containing 97.4% 2-bromopropane, no other known physical or chemical agents could be identified as responsible for the gonadal and bone marrow effects, including ionizing radiation, lead, ethylene glycol ether and its acetates, benzene, and dibromochloropropane. CONCLUSIONS: No previous studies have reported human toxicity for 2-bromopropane, but the results of this study lead to the tentative conclusion that the causal agent for the gonadal and bone marrow effects among the workers might be 2-bromopropane.

Adult↗
PubMed1995

Prophylactic extended-field irradiation of para-aortic lymph nodes in stages IIB and bulky IB and IIA cervical carcinomas. Ten-year treatment results of RTOG 79-20.

OBJECTIVES: To investigate whether irradiation to the standard pelvic field only improves the response rate and survival in comparison with pelvic plus para-aortic irradiation in patients with high-risk cervical carcinoma, and to investigate patterns of failure and treatment-related toxicity. DESIGN: Randomized controlled trial from November 1979 to October 1986, with stratification by histology, para-aortic nodal status, and International Federation of Gynecology and Obstetrics (FIGO) stage. SETTING: Radiation Therapy Oncology Group (RTOG) multicenter clinical trial. PATIENTS: A total of 367 patients with FIGO stage IB or IIA primary cervical cancers measuring 4 cm or greater in lateral diameter or with FIGO stage IIB cervical cancers were randomized to RTOG protocol 79-20 to receive either standard pelvic only irradiation or pelvic plus para-aortic irradiation. INTERVENTION: Pelvic only irradiation consisted of a midplane pelvic dose of 40 to 50 Gy in 4.5 to 6.5 weeks with daily fractions of 1.6 to 1.8 Gy for 5 d/wk. Pelvic plus para-aortic irradiation delivered 44 to 45 Gy in 4.5 to 6.5 weeks with daily fractions of 1.6 to 1.8 Gy for 5 d/wk. A total dose of 4000 to 5000 mg/h of radium equivalent or 30 to 40 Gy was provided by intracavitary brachytherapy to point A. MAIN OUTCOME MEASURES: Response rate, overall and disease-free survival, patterns of failure, and treatment-related toxicities. RESULTS: Ten-year overall survival was 44% for the pelvic only irradiation arm and 55% for the pelvic plus para-aortic irradiation am (P = .02). Cumulative incidence of death due to cervical cancer was estimated as significantly higher in the pelvic only arm at 10 years (P = .01). Disease-free survival was similar in both arms; 40% for the pelvic only arm and 42% for the pelvic plus para-aortic arm. Locoregional failures were similar at 10 years for both arms (pelvic only, 35%; pelvic plus para-aortic, 31%; P = .44). In complete responders, the patterns of locoregional failures were the same for both arms, but there was a lower cumulative incidence for first distant failure in the pelvic plus para-aortic irradiation arm (P = .053). Survival following first failure was significantly higher in the pelvic plus para-aortic arm (P = .007). A higher percentage of local failures were salvaged long-term on the pelvic plus para-aortic arm compared with the pelvic only arm (25% vs 8%). The cumulative incidence of grade 4 and 5 toxicities at 10 years in the pelvic plus para-aortic arm was 8%, compared with 4% in the pelvic only arm (P = .06). The death rate due to radiotherapy complications was higher in the pelvic plus para-aortic arm (four [2%] of 170) compared with the pelvic only arm (one [1%] of 167) (P = .38). The proportion of deaths due to radiotherapy complications in the pelvic plus para-aortic arm was higher than in the pelvic only arm (four [6%] of 67 vs one [1%] of 85; P = .24). If the patient had abdominal surgery prior to para-aortic irradiation, the estimated cumulative incidence of grade 4 and 5 complications was 11%, compared with 2% in the pelvic only arm. CONCLUSIONS: The statistically significant difference in overall survival at 10 years for the pelvic plus para-aortic irradiation arm, without a difference in disease-free survival, can be explained by the following two factors: (1) a lower incidence of distant failure in complete responders and (2) a better salvage in the complete responders who later failed locally.

Abdomen↗
PubMed1995

Aging and matrix microdamage accumulation in human compact bone.

Bone matrix microdamage in bone matrix, evidenced as microcracks, occurs consequent to cyclic loading. Microdamage caused by in vivo loading has been described in human rib cortex; however, the existence and extent of microcracks in human long bone cortices are largely unknown. Using histomorphometric methods to examine the incidence and localization of microcracks in human femoral compact bone specimens, we found that the amount of microdamage present in femoral compact bone increases dramatically with increasing age. Least squares regression analysis showed that in males, microcrack density (Cr.De., #/mm2) increases exponentially with age (r2 = 0.70). In females, Cr.De. also increases as an exponential function of increasing age (r2 = 0.79), at a significantly higher rate than in male specimens (p < 0.001). The current studies indicate that with increasing age, bone microdamage accumulates more rapidly than intrinsic processes can effect its repair. A combination of cumulative loading history, focal changes in material properties and alteration in the ability of the tissue to perceive and/or react to microcracks may all play role in this accumulation of bone microdamage with aging. This accumulation of microdamage in bone will contribute to decreased strength and stiffness. In addition, and perhaps most significantly for understanding aging and increased bone fragility, matrix microdamage in composite materials like bone will result in a profoundly reduced resistance to fracture. The importance of this accumulation of matrix microdamage in human bone with increasing age in contributing to the increased fragility of the aging skeleton is discussed.

Adolescent↗
PubMed1995

Expression of iron-regulated outer membrane proteins by porcine strains of Pasteurella multocida.

The outer membrane protein (OMP) profiles of two strains of capsular type A Pasteurella multocida isolated from the lungs of pigs with enzootic pneumonia were studied. Sarkosyl extracted OMPs from P. multocida grown under iron-restricted and iron-replete conditions were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis. Results showed that the iron-regulated outer membrane proteins (IROMPs) with molecular masses of 74 kDa, 94 kDa, 99 kDa and 109 kDa were expressed by strain A52, while 74 kDa, 82 kDa, 94 kDa and 99 kDa IROMPs were expressed by strain B80. Swine immune sera, obtained from pigs which were first immunized with a polyvalent P. multocida type A and type D bacterin and subsequently challenged with type A strain of P. multocida, contained antibodies against the IROMPs. These antibodies cross-reacted with the IROMPs expressed by avian strain P1059 of P. multocida. Convalescent-phase serum obtained from turkeys which survived fowl cholera, also cross-reacted with the IROMPs from porcine strains of P. multocida. These results suggested that IROMPs from porcine and avian strains of P. multocida may share common epitopes that were recognized by swine immune serum as well as turkey convalescent-phase serum.

Animals↗
PubMed1994

Pinhole skeletal scintigraphic manifestations of Tietze's disease.

Tietze's disease (TD) is a self-limited, non-specific, inflammatory condition of the upper costochondral junction (CCJ). Unlike in many other skeletal diseases, radiography plays a relatively minor role in TD because radiographic changes are frequently obscured by physiological costochondral calcifications. Bone scanning is a sensitive test for TD, but its specificity is low. The present study has been conducted to assess prospectively whether pinhole scintigraphy (PS) can enhance diagnostic specificity in TD. Both planar and PS bone images were obtained in seven ribs of five patients with TD. Scans alterations were analyzed and compared with the radiographic findings. Planar scans showed "hot" areas in the region of the CCJ in all seven ribs, these hot areas lacking textural patterns. However, the magnified PS images of the CCJ showed two characteristic uptake patterns: drumstick-like uptake in acute cases and C- or inverted C-shaped uptake in chronic cases. Radiographically, chondritic sclerosis could be seen when physiological chondral calcifications were minimal or absent, but was observed when the calcification was prominent. The correlation of PS and radiographic findings revealed that C- or inverted C-shaped uptake indeed faithfully reflected the inflammatory process in the CCJ, the medial border of which is concave. The further correlation of magnetic resonance and PS images of two lesions in one patient in whom histological examination was performed showed that C- or inverted C-shaped uptake is closely associated with hypervascularity of TD. Differential diagnosis between TD, fracture and metastasis is discussed.

Adult↗
PubMed1994

Effects of pretreatment transurethral resection on survival in prostatic carcinoma.

The survival of 117 patients with carcinoma of the prostate treated with radiation at SUNY-Health Science Center at Brooklyn and Kings County Hospital Center was analyzed according to their pretreatment method of diagnosis. Sixty-four patients (54.7%) underwent a transurethral resection of the prostate (TURP) for obstructive symptoms prior to definitive therapy, while 53 patients (45.3%) were diagnosed with needle biopsy. The overall 5-year survival rate was 46% in the needle biopsy group and 38% in the TURP group. Black and white patients with high Gleason scores (7 to 10) and black patients with low-grade tumors who underwent TURP had an adverse 5-year survival rate compared with those patients diagnosed by needle biopsy. The 5-year survival rate of patients with high Gleason scores comparing needle and TURP was 37% versus 16%. The 5-year survival rate of black patients with low-grade tumors comparing needle biopsy versus TURP was 50% and 22%, respectively, although not statistically significant because of the small sample size. When evaluated by stage, there was no difference in survival rates of TURP versus needle biopsy. Black patients who underwent TURP had a 28% 5-year survival rate compared with a 44% 5-year survival rate in white TURP patients. This analysis reveals that black and white patients with high-grade tumors and black patients, even with low-grade tumors, may have a lower survival rate if they undergo TURP prior to radiation, but this may be due to higher stage and larger volume disease in these patients.

Biopsy, Needle↗
PubMed1994

Isolation of a gene encoding a novel receptor tyrosine kinase from differentiated embryonic stem cells.

A mouse gene encoding a receptor tyrosine kinase, designated Embryonic receptor kinase (EmRK2), was isolated from embryoid bodies (EBs) generated by differentiating embryonic stem (ES) cells in culture for 6 days. Sequence analysis of EmRK2 cDNA clones predicts a receptor with a 755 amino acid extracellular region with seven immunoglobulin-like domains, a transmembrane region, and a 552 amino acid cytoplasmic region containing the kinase domain. The kinase domain is interrupted by a stretch of hydrophilic amino acids, the kinase insert. EmRK2 is expressed in embryoid bodies, in whole embryos at day 10 and 12 of gestation, and in the embryonic yolk sac and the fetal liver. On the basis of sequence homology, EmRK2 is likely to be the mouse homologue of human flt, a receptor for vascular endothelial growth factor, and as such, could encode an endothelial cell specific receptor tyrosine kinase.

Amino Acid Sequence↗
PubMed1993

Poor survival of black patients in carcinoma of the endometrium.

PURPOSE: To compare the prognostic factors and survivals of black and white patients with endometrial carcinoma. METHODS AND MATERIALS: A retrospective study was undertaken of a total of 290 patients with endometrial carcinoma who were treated similarly at the Health Science Center at Brooklyn and Kings County Hospital Center from 1975 and 1990. One hundred and thirty-six of 290 (47.2%) were black and 135/290 (46.9%) were white. Well-known prognostic factors affecting endometrial carcinoma were studied in black and white group of patients. Their overall survival and comparison of survival in each prognostic group were also estimated using multi-variate analysis. RESULTS: Fifty-four percent of white patients had Stage I disease, compared to 45.9% in black patients. In Stage II, 51.6% were white and 48.4% were black, and in Stage III, 88.89% were black and 11.1% were white patients (p = 0.034). Fifty six percent Grade 1 patients were white and 44% were black. In Grade 2, 53.3% were white and 46.7% were black and in Grade 3 disease, 70.5% were black and 29.5% were white (p = 0.008). Up to the inner third of myometrial invasion had occurred in 60.6% of white patients and 39.4% in black patients. The middle third of the myometrium was invaded in 60.7% of white patients, and 39.3% of black patients. Thirty-seven percent of outer third of myometrial invasion was found in white patients and 63% in black patients (p = 0.038). Seventy-two percent of positive lymph nodes were found in black patients and 28.0% in white patients (p = 0.01). Sixty-one percent of patients with positive peritoneal cytology were black as compared to 38.7% in white patients (p = 0.017). The overall ten-year corrected survival for white and black patients was 72% and 40%, respectively (p = 0.0003). Survivals comparisons, when stratified by race and each prognostic group, showed statistically significant overall survival differences in favor of white patients. CONCLUSION: Black patients with endometrial carcinoma have poor survival. Low socio-economic status (SES) would not explain these findings. More research is required to determine the cause of poor survival in black patients with endometrial carcinoma.

Adult↗
PubMed1993

Expression of a gene encoding a unique protein-tyrosine kinase within specific fetal- and adult-derived hematopoietic lineages.

A gene encoding a unique protein-tyrosine kinase was isolated by PCR from undifferentiated embryonic stem (ES) cells. The gene, Emsk (embryonic stem cell kinase), is expressed in a number of different lymphoid and myeloid hematopoietic lineages and has been shown to be identical to the recently isolated focal adhesion-associated kinase gene (Fadk). Within the nonlymphoid lineages analyzed, Emsk/Fadk was found to be expressed in primitive and definitive erythroid cells but not in mast cells or macrophages. All CD5+ (B-1a) B cells tested, as well as freshly isolated conventional (B-2) B cells, expressed readily detectable levels of Emsk/Fadk. Within the T-cell lineage, Emsk/Fadk was expressed in V gamma 5 gamma/delta cells as well as in immature alpha/beta cells found within the thymus. As the alpha/beta T-cell population matures and exits the thymus, expression of Emsk/Fadk appears to be down regulated. The expression pattern outlined here suggests a role for Emsk/Fadk in multiple stages of hematopoietic development and raises the possibility that the kinase encoded by this gene has a broader spectrum of activities than was initially suggested.

Amino Acid Sequence↗
PubMed1993

Endometrial carcinoma. Influence of prognostic factors on radiation management.

The earliest intracavitary radium treatment for uterine cancer was reported in 1908. Refinements reported during the next 20 years, using an intrauterine tube and colpostats or radium capsules, established a treatment philosophy of preoperatively irradiating uterine and parauterine tissues. Thus, preoperative intracavitary irradiation became entrenched as therapy for all endometrial cancers for the better part of four decades. In the 1950s and 1960s, the ability of external irradiation to eradicate cancer in regional lymphatic vessels prompted the use of pelvic field irradiation in Stage II and III and recurrent disease. The results of surgical exploratory studies in the 1970s established more refined criteria for preoperative or postoperative external pelvic irradiation in high-grade infiltrating Stage I cancers. In the 1980s, it became apparent that, for tumors with lymphovascular invasion, clear cell, and serous papillary histologic types, the disease spread to the upper abdomen and the paraaortic nodes might benefit from extended field and/or whole abdominal irradiation, with or without systemic bolus or concomitant continuous-infusion chemotherapy. In the 1980s, a subset of patients was identified with high-grade lymphovascular invasion clear cell and papillary serous histologic types or with positive peritoneal cytologic findings who were at high risk of failing in the paraaortic nodes and/or the upper abdomen for whom extended field or whole abdominal irradiation have been advocated. Given the fraction and dose limitation for a large abdominal field, the addition of systemic concomitant bolus or continuous infusion of chemotherapy currently is proposed to improve the control of intraabdominal failure in these high-risk patients.

Combined Modality Therapy↗