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Biomedical subjects

J C Lin

Publications and source records attributed to J C Lin.

At least 307 records · Page 17Linked to original sources
PubMed1976

Effects of prolonged quiescence on neuclei and chromatin of WI-38 fibroblasts.

DNA synthesis and cell division are markedly reduced in confluent mono-layers of WI-38 diploid fibroblasts, but resume again if the depleted medium is replaced by fresh medium containing 10% fetal calf serum. If the cells are kept quiescent for prolonged periods of time after confluence (1 or 2 weeks), the fraction of cells that can be stimulated to proliferate by fresh serum decreases and the length of the prereplicative phase increases. The template activity of isolated nuclei decreases with increasing time of quiescence, and parallel changes occur in chromatin as evidenced by circular dichroism spectra and capacity to bind the intercalating dye, ethidium bromide. When WI-38 cells are stimulated to proliferate after prolonged quiescence, the increase in template activity of nuclei is delayed by several hours in comparison to cells stimulated after short periods of quiescence. Two distinct steps, both requiring serum, can be identified in the prereplicative phase of cells stimulated to proliferative after prolonged quiescence. We interpret the results as indicating that, during prolonged quiescence, WI-38 fibroblasts go into a deeper GO state from which they can be rescued only after prolonged stimulation. In this respect, prolonged quiescence may bear some resemblance to the process of aging.

Binding Sites↗
PubMed1976

Coupling of Gaussian electromagnetic pulse into a muscle-bone model of biological structure.

The effect of angle of incidence on the transmission electromagnetic pulse with Gaussion character in biological material is studied. The model assumed is a layer of soft tissue over a semi-infinite medium of boney structure governed by alpha dispersion. The numerical results demonstrate that the transmitted pulse strength is the greatest when the pulse is incident normally on the air-tissue interface. The coupling efficiency for a one microsecond pulse is three times as big as that for a ten microsecond pulse.

Bone and Bones↗
PubMed1976

Microwave auditory effect- a comparison of some possible transduction mechanisms.

When human subjects are irradiated with pulse modulated microwave energy they report the perception of a sound that appears to originate from within or slightly behing the head. Three of the possible mechanisms are examined using first order mathematical approximations and several simplifying assumptions. The results show that while all three (radiation pressure, strictive force and thermal expansion) are capable of producing the phenomenon, the stress resulting from thermal expansion may be so great that it masks the effect of the others completely.

Hearing↗
PubMed1976

Salt extraction of chromatin from normal diploid and SV-40 transformed human fibroblasts.

Regulation of cell proliferation is a complex but exceedingly interesting form of gene expression. Overwhelming evidence in the past ten years has shown that the flow of cells through the cell cycle, and the regulation of cell population density, are under the control of the eukaryotic genome. Changes in the function and structure of chromatin have been reported when G0 cells are stimulated to proliferate and when continuously dividing cells move through the different phases of the cell cycle from G1 to S, G2 and mitosis. The changes occurring in the structure and function of chromatin seem to be related to changes occurring in the chromosomal proteins, especially non-histone chromosomal proteins and chromatin-bound protein kinases. Studies are now in progress to isolate the genes, with their respective proteins, that regulate the different steps of the cell cycle.

Animals↗
PubMed1976

Microwave-induced hearing: some preliminary theoretical observations.

Pulsed microwaves impinging on the head of animals and man produce auditory sensations. Theoretical analyses indicate a series of resonant frequencies occurring inside the head. This is supported by previous observations of characteristic oscillations recorded from the round window of mammals during pulsed microwave irradiation.

Animals↗