Biomedical subjects

T C Fong

Publications and source records attributed to T C Fong.

29 records · Page 2Linked to original sources

PubMed1989

Increase in Tac mRNA expression in natural killer-like cell line in response to interleukin-1 and interleukin-2 shown at the population and cellular level by in situ hybridization.

Our previous results have shown that the increased expression of the Tac component of the interleukin-2 (IL-2) receptor at the surface of a natural killer-like cell line (YTN10) in response to interleukin-1 (IL-1) is associated with an eightfold increase in Tac mRNA production. Tac expression was detected by flow cytometry and anti-Tac binding studies, and mRNA synthesis was assessed by Northern and dot blots. These findings have now been extended utilizing recombinant IL-1 and autoradiographic techniques in experiments using both the parent YT and YTN10 cells. In situ hybridization experiments have shown that the increase in mRNA expression is manifested both in the percentage of cells expressing it and in the level of expression per cell. Consistent results were obtained in both sublines. In addition, exposure of both sublines to recombinant IL-2 also induced increased Tac mRNA synthesis, while inducing only a marginal increase in Tac expression at the membrane level.

Cell Line↗

PubMed1988

Increased binding of IL-2 and increased IL-2 receptor mRNA synthesis are expressed by an NK-like cell line in response to IL-1.

An NK-like cell line (YTN10 cells) was stimulated with IL-1, and the IL-2R, as detected by flow cytometry analysis using fluorescein-labeled anti-IL-2R (Tac) antibody, increased displaying a dose-response curve in the shape of an inverted "U." This was associated with increases in 1) the number of high affinity binding sites for IL-2 (Kd approximately 45 pM) which increased from 1270 to 4220 sites per cell, and 2) the number of binding sites for anti-Tac antibody, which increased from 999 to 6763 sites per cell. They were both detected by using radiolabeled ligand-binding methods which are one to three orders of magnitude more sensitive than flow cytometry analysis. No binding sites with low affinity for IL-2 could be detected on untreated or treated cells. However, a change was noted in the number of IL-2 binding sites with intermediate affinity (Kd approximately 1000 pM), which increased from 54,000 to 67,000 sites per cell. This binding affinity is equivalent to that of the p70 IL-2-binding protein detected on YT cells and on large granular lymphocytes by other investigators. This suggests that the increase in the Tac peptide was the limiting factor in the combination of the Tac and p70 components to form the high affinity IL-2R. The corollary is that all new Tac molecules were incorporated into these R. The IL-1 treatment also induced an increase in production of Tac mRNA as detected by Northern blots. Comparison of the relative amounts of Tac mRNA by dot blots verified the quantitative difference between treated and untreated cells. These data demonstrate that the IL-1-induced positive regulation of the Tac protein and high affinity IL-2R on YTN10 cells may operate at the level of gene transcription.

Antigens, Surface↗

PubMed1988

Decreased in vitro polymerase II activity of whole-cell extracts from late passage human diploid fibroblasts.

Age-associated decreases in gene expression have been observed in several different species, but the mechanisms of the decrease have not yet been adequately studied at molecular level. Using an in vitro transcription assay, we have obtained data suggesting that there is an age-associated decrease in polymerase II-specific transcriptional activity in fibroblasts aged in vitro.

Aging↗

PubMed1988

Pulmonary function testing in predicting complications from percutaneous lung biopsy.

Percutaneous needle biopsy is an accepted method of obtaining tissue for diagnosis of lung tumors. The depth of the lesion, size of the needle, operator experience, and the presence of emphysema have been identified as factors influencing the risk of postbiopsy pneumothorax, the most common complication. In this retrospective study of 308 patients, we enquired whether pulmonary function tests (available in 138 patients) and arterial PO2 (available in 103 patients) might predict the risk of pneumothorax following percutaneous needle biopsy. We found that as airway obstruction increases (FEV1.0/FVC less than 59% of predicted) or as arterial oxygenation decreases (PO2 less than 59 mm Hg), not only does the incidence of pneumothorax increase, but symptoms are more severe in that the number of pneumothoraces requiring chest tube drainage increases as well. We suggest that airway obstruction and arterial oxygenation are factors indicative of increased risk identifying patients who need close scrutiny after the procedure.

Airway Obstruction↗

PubMed1987

Miliary pattern as presentation of leiomyomatosis of the lung.

A 30-year-old woman presented with progressive dyspnea on exertion and a rapidly-growing uterine mass. Chest x-ray examination revealed a miliary interstitial nodular pattern in both lung fields. Transbronchial biopsy yielded lung tissue containing multiple nodules of smooth muscle, consistent with benign metastasizing leiomyoma. Subsequent hysterectomy revealed an atypical cellular leiomyoma. We wish to emphasize the need for chest x-ray examination in the workup of uterine tumors in women of reproductive age.

Adult↗

PubMed1987

Q fever inflammatory pseudotumor of the lung.

A 36-year-old man presented with malaise, myalgia, fever, and weight loss. Liver function tests were moderately abnormal and chest x-ray film revealed an irregular mass in the right lower lobe. Bronchoscopy with cytology was not helpful. Serology revealed markedly elevated titers to Q fever. The mass was presumed to represent the presence of a Q fever pseudotumor. The patient responded to therapy with resolution of symptoms and chest x-ray film and decrease in titers to Q fever.

Adult↗

PubMed1987

Cellular, biochemical, and molecular basis of T-cell senescence.

The elucidation of age-related changes in immune functions is of great importance in light of the rising susceptibility of elderly individuals to infections, the likelihood that immunosenescence might also contribute to the age-related rise in cancer, and the role autoantibodies and immune complexes might play in general physical deterioration of aging individuals through their participation in subclinical chronic tissue damage. An attempt has been made to summarize our present knowledge on immune functions that are vulnerable to aging. It revealed that at the cellular level, all four antigen-responsive immune cells (T cells, B cells, monocytes, and killer cells) are vulnerable to aging, but T cells are perhaps the most vulnerable. Therefore, this article specifically examines the cellular and biochemical T cell-dependent concomitants of age-altered immune functions. One picture that is emerging suggests that at the molecular level, several control points exist along the path of gene expression that could be vulnerable to aging.

Aging↗

PubMed1985