Biomedical subjects

R L Wu

Publications and source records attributed to R L Wu.

40 records · Page 3Linked to original sources

PubMed1980

Is diagnostic gonadotrophin stimulation useful?

Urinary excretion of oestrogens in response to stimulation with a standardized dose of gonadotrophin has been used previously in the differential diagnosis of oligomenorrhoea/amenorrhoea. Patients with polycystic ovarian disease were said to have a characteristic excessive response. In the present study, some patients with laparoscopically proven polycystic ovaries did not show such an excessive response, while others with laparoscopically normal ovaries did. A high LH/FSH ratio correlated well with the laparoscopic finding of polycystic ovaries. It is concluded that where there are adequate facilities for diagnostic laparoscopy and determination of plasma gonadotrophins, there is no further place for the routine use of the standardized gonadotropin stimulation test in the evaluation of suspected polycystic ovarian disease.

Adult↗

PubMed1980

Specific tumor immunity induced with mitomycin C-treated syngeneic tumor cells (MCT). Effects of carrageenan and trypan blue on MCT-induced immunity in mice.

Mitomycin C treatment of 3-methylcholanthrene-induced syngeneic tumor cells in male mice of the highly inbred strain CBA/WEHI was a convenient and effective method for producing viable but nondividing tumor cells. A single sc injection of 1 x 10(6) mitomycin C-treated syngeneic tumor cells (MCT) induced a specific antitumor immune response that could mediate rejection of small subcutaneous tumor grafts and substantially inhibit growth of larger grafts in normal mice. The response was evident between 3 and 7 days after immunization and persisted for at least 120 days. Adoptive transfer experiments with peritoneal exudate cells from MCT-immunized mice indicated that a cellular basis for resistance was likely in the absence of a detectable humoral component. Administration of MCT to mice with established tumor grafts did not, however, affect tumor growth. Experiments with carrageenan and trypan blue showed that neither induction nor expression of cytotoxic effector cells in MCT-immunized mice was inhibited by these substances, though carrageenan and trypan blue augmented tumor growth in normal mice.

Animals↗

PubMed1979

Effects of carrageenan, PVP and tumour-bearer serum on immunity induced by excision or mitomycin C-treated tumour cells in mice.

Carrageenan (Cg) was tested for its effects on the growth of, and immunity to, 2 methylcholanthrene-induced syngeneic murine fibrosarcomas (H1 and H2). The tumours were found not to share major tumour-specific transplantation antigens. H2 appeared more immunogenic than H1. In contrast to H1, immunity induced by H2 was not affected by Cg, nor was its growth in Cg-treated normal mice augmented.Postoperative i.p. injections of Cg abolished the weak anti-H1 immunity produced by H1 tumour excision. Furthermore, the subsequent growth of the H1 tumour challenge in the Cg-treated immune mice was significantly greater than the augmented growth in Cg-treated normal mice. The Prior administration of the macrophage-stabilizing agent polyvinylpyrrolidone (PVP) to immune mice significantly reduced the augmenting effect of Cg. The growth-promoting effect of Cg on a secondary H1 tumour challenge in mice immunized by tumour excision was abolished by 10(6) MCT-H1 cells injected s.c. before Cg. In contrast to the immunity induced by tumour excision, Cg did not abolish the immunity induced by the injection of MCT-H1 cells.Passive administration of H1 tumour-bearer serum (TBS) did not enhance the growth of H1 cells in normal mice, nor did TBS abrogate the specific cell-mediated immunity (CMI) induced in vivo by MCT-H1 cells. However, TBS administered to Cg-treated, MCT-H1-immune mice abolished tumour immunity.We propose that TBS does not inhibit CMI in vivo provided that macrophages remain functional, but may do so when macrophages are rendered defective by antimacrophage agents or by products of neoplastic cells. Increasing the levels of specific effector cells can over-ride the inhibiting effects of TBS, even when defective macrophages are present.

Animals↗

PubMed1979

Effect of carrageenan on the non-specific resistance of mice to injected syngeneic tumour cells, alone or in mixtures.

The mechanisms of non-specific resistance to syngeneic methylcholanthrene-induced fibrosarcomas of mice were investigated. Results showed that a small tumour graft of 0.05 X 10(5) cells is greatly enhanced in growth when admixed with large numbers of cell fragments, killed cells or viable non-replicating cells. The enhancement of small tumour grafts in cell mixtures was found to be non-specific. Carrageenan, a known anti-macrophage agent, significantly increased tumour growth in normal mice. However, it did not enhance the increased tumour growth of 0.05 X 10(5) cells mixed with 10(6) viable, non-replicating mitomycin C-treated tumour cells. The latter observation indicates that carrageenan and admixed cells interfere with the same tumour-inhibitory mechanism and therefore cannot produce additive effects. The results give support to the concept of a non-specific macrophage "surveillance" system which appears crucial in controlling tumour growth, since it determines the establishment of small numbers of tumour cells while they can still be easily destroyed.

Animals↗