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Biomedical subjects

H K Song

Publications and source records attributed to H K Song.

101 records · Page 6Linked to original sources
PubMed1990

Oestrogen receptor B-region polymorphism and spontaneous abortion in women with breast cancer.

To examine whether a variant human oestrogen receptor gene, which differs from the wild-type gene in the B region, was associated with spontaneous abortion, obstetric histories of breast cancer patients with this variant were compared with those of breast cancer patients with the wild-type gene. In women with the B-variant, 50% of pregnancies ended in spontaneous abortion, compared with 10% for women homozygous for the wild-type gene. B-variant women also had a higher proportion of spontaneous abortions and a higher number of spontaneous abortions per woman than did those with the wild-type gene.

Abortion, Habitual↗
PubMed1989

Diminished corticosterone levels in nude mice implanted with MCF-7 or ZR-75-1 human breast tumor cells.

Corticosteroid levels were studied in the plasma of athymic mice implanted with human breast tumor cells, either from MCF-7 or ZR-75-1 cell lines. There was a highly significant decrease in plasma corticosterone levels in the mice implanted with these tumor cells. There was no significant effect on corticosterone of GW 39 colon cancer cells, LS 174T colon cancer cells, or Calu-3 lung cancer cells.

Animals↗
PubMed1989

Activity of pp60c-src protein kinase in human breast cancer.

Because there is elevation of pp60c-src activity in breast carcinoma tissue, we analyzed primary breast cancer tissue samples from 30 women to determine whether pp60c-src activity correlated with specific clinical parameters. We found that tumors with a progesterone receptor had higher pp60c-src activity than tumors without such a receptor. But there was no association of pp60c-src activity with the presence of an estrogen receptor or of nodes, or with menopausal status or age. The function of pp60c-src in normal cells and in breast cancer is unknown, as is the significance of our finding of an association of elevated pp60c-src activity and the presence of progesterone receptors.

Adult↗
PubMedDate not supplied

Field strength and angle dependence of trabecular bone marrow transverse relaxation in the calcaneus.

The contribution from reversible dephasing, R2', to the effective transverse relaxation rate, R2*, in trabecular bone marrow, is governed by the magnetic field inhomogeneity induced by the difference in diamagnetic susceptibility between bone and bone marrow and should, therefore, scale linearly with field strength. Measurement of R2' in the calcaneus at 1.5 and 4 T by means of the GESFIDE (gradient-echo sampling of free induction decay and echo) pulse sequence showed R2' to increase by a factor of 2.73 at the higher field, which is close to the ratio of the field strengths (2.67). At both field strengths, R2' dominates R2*, contributing more than 90% to the total relaxation rate at 4 T. The data further indicate large regional variations within the calcaneus and a notable dependence of R2' on the angle of the foot relative to the direction of the static field. The findings have implications on the choice of the calcaneal site for assessment of trabecular density.

Adult↗
PubMedDate not supplied

Proton T1rho-dispersion imaging of rodent brain at 1.9 T.

Detection of H2(17)O with proton T1rho-dispersion imaging holds promise as a means of quantifying metabolism and blood flow with MRI. However, this technique requires a priori knowledge of the intrinsic T1rho dispersion of tissue. To investigate these properties, we implemented a T1rho imaging sequence on a 1.9-T Signa GE scanner. A series of T1rho images for different locking frequencies and locking durations were obtained from rat brain in vivo and compared with 5% (wt/vol) gelatin phantoms containing different concentrations of (17)O ranging from .037% (natural abundance) to 2.0 atom%. Results revealed that, although there is considerable T1rho-dispersion in phantoms doped with H2(17)O, the T1rho of rat brain undergoes minimal dispersion for spin-locking frequencies between .2 and 1.5 kHz. A small degree of T1rho dispersion is present below .2 kHz, which we postulate arises from natural-abundance H2(17)O. Moreover, the signal-to-noise ratios of T1rho-weighted images are significantly better than comparable T2-weighted images, allowing for improved visualization of tissue contrast. We have also demonstrated the feasibility of proton T1rho-dispersion imaging for detecting intravenous H2(17)O on a live mouse brain. The potential application of this technique to study brain perfusion is discussed.

Animals↗