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Biomedical subjects

W Choi

Publications and source records attributed to W Choi.

48 records · Page 3Linked to original sources
PubMed1994

Complete nucleotide sequence and tissue-specific expression of the rat phenylethanolamine N-methyltransferase gene.

The rat phenylethanolamine N-methyltransferase (PNMT) gene was isolated from a genomic library by cross-hybridization with a bovine PNMT cDNA probe. Complete nucleotide sequence analysis of a genomic clone showed that this gene contained three exons and spanned about 2.8 kb in length. There were the acute-phase response element, TATA, SP1, and GRE sequences. The physicochemical properties of rat adrenal PNMT were different from those of the brainstem PNMT. However, northern blot and reverse transcription-polymerase chain reaction analysis showed that the rat PNMT gene may not express the multiple forms of mRNA. These results suggest that the rat PNMT gene might produce a single enzyme protein, whose activity may be differentially modulated by tissue-specific environment in the central and peripheral systems.

Adrenal Glands↗
PubMed1993

Ligand binding characteristics of [3H] dihydroalprenolol in cerebral cortical membranes of young and old senescence-accelerated mouse.

1. The values of both Kd and Bmax of [3H] dihydroalprenolol binding in the cerebral cortical membranes of old-aged (12 month old) SAM-P/1 were not significantly different compared with those of young (2 month old) SAM-P/1. 2. The values of Ki of metoprolol in the young and old aged SAM were 119 +/- 39.5 nM and 157 +/- 55 nM, respectively. 3. The values of beta 1/beta 2 ratio of the young and old aged SAM were 1.67 +/- 0.15 and 1.64 +/- 0.13, respectively. 4. These results suggest that there were no significant changes of binding characteristics of beta 1 and beta 2 adrenoceptors during aging in the cerebral cortex of SAM.

Aging↗
PubMed1992

Lung cancer following Hodgkin's disease: a case-control study.

It is recognized that survivors of Hodgkin's disease are at a substantially increased risk of lung cancer. A collaborative group of population-based cancer registries and major treatment centers carried out a case-control study, in which 98 cases of lung cancer were identified in patients who had survived at least 1 year following a diagnosis of Hodgkin's disease. A total of 259 matched controls were selected from patients with Hodgkin's disease who did not develop subsequent lung cancer, and for both cases and controls detailed information was abstracted from medical records concerning stage and treatment of Hodgkin's disease. Patients treated with chemotherapy alone had about twice the risk of developing lung cancer than those treated by radiotherapy alone or both modalities. There was no increase in risk with cumulative number of cycles of chemotherapy. Among patients treated with radiotherapy alone, there was an increase in risk related to estimated radiation dose to the lung. There was also a strong association between cigarette smoking and the risk of lung cancer. The finding of a higher risk following chemotherapy than following radiotherapy was unexpected, but could not be explained by any identified methodological flaws. A plausible inference from the study is that all forms of Hodgkin's disease therapy are carcinogenic to the lung and that, in particular, chemotherapy is associated with an increase in risk which is at least comparable to and perhaps higher than the risk produced by radiotherapy.

Antineoplastic Agents↗
PubMed1992

Public objections to environmental tobacco smoke.

METHODS. A randomly selected sample of Californian adults was surveyed by telephone to assess their knowledge, attitudes, and behaviors with respect to tobacco use and its control. The questions asked of this sample were whether they had recently (in the past 12 months) asked someone not to smoke in certain situations and whether they would ever consider doing such a thing. RESULTS. Results of the survey indicated that 59.1% of nonsmokers and 44.4% of smokers had asserted themselves within the past 12 months, while another 28.2 and 29.1% of the nonsmokers and smokers, respectively, indicated that they would consider asking someone not to smoke. Only 12.7% of the nonsmokers and 26.4% of the smokers indicated that they would not consider doing such a thing. Those more likely to object publicly to tobacco smoke are generally younger, are more educated, and have anti-tobacco attitudes related to either a specific health belief or social influence.

Adolescent↗
PubMed1991

Radon exposure, cigarette smoking, and other mining experience in the beaverlodge uranium miners cohort.

A nested case-control study within the Beaverlodge Uranium Miners Cohort was undertaken to assess any possible contribution of confounding by smoking and other mining experience to the risk estimate derived from the original cohort study. Next of kin have been interviewed for 46 lung cancer cases and 95 controls enrolled in the Beaverlodge Uranium Miners Cohort Study who died between 1950 and 1980. Confounding by cigarette smoking and other mining experience appears unlikely to have contributed to the relative risk coefficient for exposure to Rn decay products derived in the parent study. Data for smoking and exposure to Rn decay products are consistent with a multiplicative model, although considerable caution must be applied to this interpretation.

Case-Control Studies↗
PubMed1990

Cloning and analysis of the pseudogene for human epinephrine synthesizing enzyme, phenylethanolamine N-methyltransferase (PNMT).

1. This gene completely lacks the intervening sequences. 2. This gene is truncated at the 5' end peptide encoding region by 433 base pairs (bp). 3. The 502 bp of this gene containing poly(A) signal are completely identical to the 3' half of mRNA encoding region of functional gene. 4. This gene has a poly(A) tail and is flanked by direct repeat of 6 bp. 5. Here we report for the first time the complete sequence of a human pseudogene for phenylethanolamine N-methyltransferase and this is the first report of cloning of pseudogene for catecholamine biosynthetic enzymes.

Amino Acid Sequence↗
PubMed1984

Association between reported diet and all-cause mortality. Twenty-one-year follow-up on 27,530 adult Seventh-Day Adventists.

This report examines the association between mortality from all causes during a 21-year period and frequency of consumption of 28 specific foods among 27,530 adult California members of the Seventh-Day Adventist Church. Food consumption was measured at the beginning of the study (1960) by a self-administered questionnaire. Deaths were identified by computer-assisted matching of study subjects to the file of death certificates for all deaths that occurred in California during 1960-1980. All-cause mortality showed a significant negative association with green salad consumption and a significant positive association with consumption of eggs and meat. For green salad and eggs, the association was stronger for women; for meat, the association was stronger for men. All the observed associations were adjusted for age, sex, smoking history, history of major chronic disease, and age at initial exposure to the Adventist Church.

Adult↗
PubMed1984

Diet, obesity, and risk of fatal prostate cancer.

Findings described in this report are for 6,763 white male Seventh-day Adventists who completed a dietary questionnaire in 1960. Between 1960 and 1980 mortality data were collected on cohort members. Overweight men had a significantly higher risk of fatal prostate cancer than men near their desirable weight. The predicted relative risk of fatal prostate cancer was 2.5 for overweight men. Suggestive positive associations were also seen between fatal prostate cancer and the consumption of milk, cheese, eggs, and meat. There was an orderly dose-response between each of the four animal products and risk. The predicted relative risk of fatal prostate cancer was 3.6 for those who heavily consumed all four animal products. The results of this study and others suggest that animal product consumption and obesity may be risk factors for fatal prostate cancer.

Aged↗
PubMedDate not supplied

Expression of Alzheimer's amyloid precursor protein in human lymphocyte.

Beta-amyloid precursor protein (betaAPP) has been shown to be involved in cell growth regulation. In spleen, the majority of cells showing betaAPP like immunoreactivity was found in the T cell-dependent zone. In Northern blot, the expression of betaAPP was increased to reach the peak at 72 h after the treatment of phytohemagglutinin (PHA). But, in cytofluorometry, almost all CD4(+) T helper/inducer cells and the majority of CD(8+) T suppressor/cytotoxic cells show betaAPP immunoreactivity which remained constant during the stimulation with PHA. These results suggest that betaAPP is a surface molecule of T lymphocyte and the turnover or release of APP might be increased with the treatment of T cell mitogen.

Journal Article↗
PubMedDate not supplied

Ultrastructural changes in microvessel with age in the hippocampus of senescence-accelerated mouse (SAM)-P/10.

Microvessels in the hippocampus of aged SAM-P/10 (14 months old) showed the following ultrastructural changes compared with those of young-mature controls (3 months old): (1) the majority of capillaries had lost the smooth contours typical of young cases; (2) the luminal surface of capillaries showed irregularity; (3) the endothelial cytoplasm was thicker; (4) vesicles appeared more frequently in the endothelium; (5) interendothelial tight junctions and basement membranes, however, seemed to show no significant abnormalities; (6) pericytes, especially those of arterioles and venules, contained many enlarged cytoplasmic inclusions with honeycomb-like vacuoles; (7) the area of glial perivascular end feet was greater. These morphological findings raise the possibility of impaired blood-brain barrier function and microhemodynamic disturbances in aged SAM-P/10 hippocampus.

Aging↗
PubMedDate not supplied

Adjuvant internal hepatic radiotherapy using colloidal 32P chromic phosphate in colorectal cancer.

The purpose of the study is to investigate the value of adjuvant radiotherapy given in the form of colloidal chromic phosphate 32P suspension administered via portal vein, in preventing the growth of occult metastases in the liver. Twenty two patients (10 patients of treated group with 12 controls) were followed 12 months after operation. There was no significant change in the CBC and liver functions after administration of 32P labeled colloidal chromic phosphate. Although local recurrence rates were very similar in both groups of colorectal cancer (3/12 in the control group and 4/10 in the treated group), liver metastasis rates were quite different: 4/12 in the control group and none (0/10) in the treated group. In conclusion, 32P labeled colloidal chromic phosphate is expected to prevent liver metastases of completely resected colorectal cancer.

Chromium↗