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Biomedical subjects

K W Choi

Publications and source records attributed to K W Choi.

62 records · Page 4Linked to original sources
PubMed1971

Immunoglobulin production by human lymphocytoid lines and clones: absence of genic exclusion.

Immunoglobulin production was studied in established lines of normal human lymphocytes. Three lines which produced both immunoglobulin G and immunoglobulin M were cloned. Among the 25 immunoglobulin-producing clones, 23 produced both classes of immunoglobulins. These findings suggest that the phenomenon of genic exclusion does not hold for immunoglobulin production in lymphocytoid cells in culture.

Cell Line↗
PubMed1970

Biochemically marked lymphocytoid lines: establishment of Lesch-Nyhan cells.

Two lymphocytoid cell lines have been established from a patient with the Lesch-Nyhan syndrome. The cells are deficient in hypoxanthine-guanine phosphoribosyltransferase, as demonstrated by their failure to incorporate [H(3)]hypoxanthine and by their inability to grow in medium in which they were nutritionally dependent upon exogenous hypoxanthine. This represents the first establishment of presumptively permanent human lymphocytoid cell lines that are deficient in a specific enzyme.

Athetosis↗
PubMed1970

Chromosome aberrations among the Yanomamma Indians.

The chromosomes of leucocytes cultured from the peripheral blood of 49 primitive Yanomama Indians of Venezuela were studied to determine the types and frequencies of aberrations in a human population not exposed to the same exogenous agents as civilized man. In all but one instance, 100 cells per individual were scored. In 13 cases, we found one or more cells with multiple complex breaks and rearrangements, represented by tetracentric, tricentric, and numerous dicentric chromosomes. From the standpoint of chromosomal damage, these cells are among the most abnormal cells yet described in vivo in man, and were not seen in the controls. There was also a higher than expected frequency of cells with an isolated structural aberration in both Indians and controls. This may be the result of a 24- to 48-hour delay in the initiation of culture. The cause of the more extensive damage to some cells remains to be determined.

Asian People↗
PubMedDate not supplied

Role of autonomic dysfunction in patients with functional dyspepsia.

BACKGROUND: The role of autonomic dysfunction in patients with functional dyspepsia is not completely understood. AIMS: 1. to prospectively assess abnormalities of autonomic function in patients with functional dyspepsia, 2. to assess whether autonomic dysfunction in these patients is associated with a. visceral hypersensitivity or b. delayed gastric emptying or c. severity of dyspeptic symptoms. PATIENTS: A series of 28 patients with functional dyspepsia and 14 healthy volunteers without gastrointestinal symptoms were studied. METHODS: All patients and controls were submitted to a battery of five standard cardiovascular autonomic reflex tests, dyspeptic questionnaire, gastric barostat tests and gastric emptying tests. RESULTS: 1. Autonomic function tests showed that both sympathetic and parasympathetic scores of dyspeptic patients were significantly higher than in controls; 2. visceral hypersensitivity was confirmed in dyspeptics in response to proximal gastric distension, demonstrating lower pain threshold; 3. delayed gastric emptying occurred more frequently in patients with functional dyspepsia than in controls; 4. epigastric pain and epigastric burning were significantly more prevalent in patients with definite evidence of autonomic dysfunction; 5. No significant association was found between presence of autonomic dysfunction and presence of visceral hypersensitivity or presence of delayed gastric emptying in patients with functional dyspepsia. CONCLUSIONS: We concluded that a possible role of autonomic dysfunction in eliciting dyspeptic symptoms could not be determined from alterations in visceral hypersensitivity or delayed gastric emptying. Autonomic dysfunction might not be the major explanation for symptoms associated with functional dyspepsia.

Abdominal Pain↗
PubMedDate not supplied

Expression of beta-catenin in human testes with spermatogenic defects.

beta-catenin is a multifunctional molecule that functions in intercellular adhesion and signal transduction during assembly of AJs between Sertoli cells as well as between Sertoli cells and germ cells. To assess changes in the testicular beta-catenin in male infertility conditions, testicular tissues from obstructive azoospermia with normal spermatogenesis, spermatogenic arrest (SA) and Sertoli cell-only syndrome (SCO) patients were examined for immunohistochemical localization of beta-catenin. In normal spermatogenic tissue, expression of beta-catenin was largely found in the Sertoli cell-germ cell (primarily spermatocytes) contact areas. Interestingly, perinuclear localization of beta-catenin was found in spermatocytes and spermatids. In spermatogenic arrest, beta-catenin in cell contact areas between Sertoli cells and germ cells was greatly decreased, but perinuclear beta-catenin in spermatocytes was not. In SCO, weak or negligible immunoreactivity of beta-catenin was found in cell contacts between Sertoli cells. Nuclear localization of beta-catenin was found in myotubular cells in all samples. Taken together, altered expression of beta-catenin in cell contacts within the seminiferous epithelia in spermatogenic arrest and SCO suggests that interactions between Sertoli cells and germ cell are crucial for expression of beta-catenin, and thus functional development of AJs in seminiferous epithelia in human testis. It should be also emphasized that perinuclear beta-catenin in germ cells may play a specific role in spermatogenesis.

Cytoskeletal Proteins↗
PubMedDate not supplied

Interaction between cyclooxygenase-2 and inducible nitric oxide synthase in gastric cancer.

BACKGROUND: Chronic expression of cylcooygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) may play an important role in gastric carcinogenesis. Thus, the purpose of our study was to assess the expression of COX-2 and iNOS messenger RNA (mRNA) in gastric cancer and to investigate the correlation between the expression of COX-2 and iNOS mRNA in these patients. STUDY: Twenty-three gastric carcinoma specimens and accompanying adjacent specimens were obtained from surgical resection. The expression of COX-2 and iNOS were examined by comparative reverse transcription polymerase chain reaction. RESULTS: Cylcooygenase-2 and iNOS mRNA were significantly higher in gastric cancer tissues than in adjacent normal tissues. There was significant correlation between the levels of COX-2 and iNOS mRNA in carcinoma tissues. However, there was no significant correlation between the level of COX-2 or iNOS mRNA expression and several clinicopathologic parameters in these patients. CONCLUSION: The expression of COX-2 and iNOS may be one of the factors that contribute to gastric carcinogenesis.

Adenocarcinoma↗
PubMedDate not supplied

A double-blind, randomized, parallel group study of omeprazole and ranitidine in Korean patients with gastric ulcer.

The efficacy of the proton pump inhibitor omeprazole, 20 mg every morning, was compared with that of the H2-receptor antagonist ranitidine, 150 mg every morning and at bedtime, in a double-blind randomized parallel group study in 250 patients with gastric or prepyloric ulcers. At both 4 and 8 weeks, significantly more patients had healed ulcers in the omeprazole group than the ranitidine group, whether the results were analysed on a per-protocol or an intention-to-treat basis. At 4 weeks, 74% of patients in the omeprazole group were healed compared with 51% in the ranitidine group (P = 0.001), and at 8 weeks the corresponding values were 99 and 82% (P = 0.001, per-protocol cohort). Omeprazole treatment and small ulcer size significantly increased the probability of healing, but smoking had no significant effect. Patients in the omeprazole group had significantly fewer occurrences of daytime epigastric pain during the first 4 weeks than the ranitidine group (P = 0.0037), as shown by their diary cards. Both treatments were well tolerated.

Adult↗