Biomedical subjects

J Lu

Publications and source records attributed to J Lu.

690 records · Page 39Linked to original sources

PubMedDate not supplied

Immunodetection of thiol proteinase levels in various populations of Artemia cysts and during development.

An immunodetection assay on Western blots has been used to determine the thiol proteinase content and composition in cysts from 12 populations of the brine shrimp Artemia. Our results showed no differences in the subunit composition of the thiol proteinase among cysts from eight bisexual strains and four parthenogenic strains, and confirmed an earlier finding that the proteinase is composed of two subunits of 25.9 and 31.5 kilodaltons. In contrast, we found that Artemia cysts from parthenogenic strains contain 17.1 ng/cyst of the thiol proteinase, while cysts from bisexual strains contain 8.2 ng/cyst of the thiol proteinase. Also, there was a good linear correlation (r = 0.863; p less than 0.001) between the thiol proteinase content and cyst mass. Embryo fractionation experiments showed that 82% of the thiol proteinase was in the cytosol, while 14 and 4%, respectively, were in the nuclei/yolk platelets and mitochondria/lysosome fractions. Measurements of the thiol proteinase content of developing Artemia embryos showed that the proteinase content was relatively constant during early development, suggesting that the activity of the thiol proteinase gene(s) may be constitutive and not developmentally regulated in Artemia embryos.

Animals↗

PubMedDate not supplied

Intratumoral injection of boiling carboplatin (BCBP) solution for treatment of liver cancer in the animal model.

BACKGROUND/AIMS: To develop a new modality of local hyperthermal chemotherapy for liver cancer. METHODOLOGY: Carboplatin solutions of various concentrations were heated at 60 degrees C, 80 degrees C and 100 degrees C, and carboplatin content, pH value and ultraviolet absorption spectrum were assayed before and after heating. By establishing BALB/c murine model of subcutaneous transplant liver cancer, intratumoral injection of boiling carboplatin solution (group A), 45 degrees C carboplatin solution (group B), room-temperature carboplatin solution (group C), boiling distilled-water (group D) and room-temperature distilled-water (control group) was carried out, and tumor growth curve, tumor regression rate and pathohistological features following treatment were evaluated. RESULTS: Carboplatin content remained stable, ultraviolet absorption spectrum presented no remarkable changes and pH value showed a slight decline after being heated for up to 20 min. Following treatment, all 16 tumors in group A were completely regressed up to day 21. In groups B, C and control group, no tumors became fully regressed and a size of 1.98 +/- 1.11 cm2, 1.50 +/- 0.58 cm2 and 4.83 +/- 0.37 cm2 was presented on day 21, respectively. In group D, though all tumors grossly disappeared during the early post-treatment days, 12 out of 16 recurred on day 21. The tumor regression rate in group A was significantly lower as compared with that of groups B, C, D and control group (all P < 0.01). Histological examination revealed massive necrosis with some degenerated tumor cells at the tumor margin in groups A and D, and only focal necrosis with more viable tumor cells at the center and margin in groups B and C on post-treatment day 1 and 3. Twenty-one days after injection, all tumors in group A presented complete necrosis and were partly replaced by fibrotic tissue. Except for 4 regressed tumors in group D which had the same histological features as those in group A, all other tumors in groups B, C, D and control group presented the same histological features as those untreated. CONCLUSIONS: Carboplatin solution remained stable at boiling status. Intratumoral injection of boiling carboplatin solution could completely devitalize liver cancer tissue via synergistic effects of direct tumoricidal role of heat and the heat-enhanced tumoricidal role of carboplatin.

Animals↗

PubMedDate not supplied

Effects of androgen, fibroblast growth factors or other various growth factors on growth of Shionogi carcinoma cells in a protein-free medium.

Shionogi carcinoma 115 (SC115) has been accepted for 20 years as an androgen-responsive mouse mammary tumor. We have recently established an androgen-dependent cloned cell line (SC-3) from a SC115 tumor. We found in the present study that the growth of SC-3 cells can be stimulated by 10(-8) M testosterone (up to 100-fold) even in a protein-free medium beginning from plating [Ham's F-12: Eagle's minimum essential medium (1:1, v/v)]. In the protein-free culture, the proliferation of SC-3 cells was also found to be stimulated by acidic or basic fibroblast growth factor (FGF) alone (up to 50-fold) among various growth factors examined such as FGFs, insulin, insulin-like growth factor (IGF)-I, IGF-II, nerve growth factor, platelet-derived growth factor, epidermal growth factor, transforming growth factor (TGF)-alpha and TGF-beta. The testosterone (10(-8) M)- or FGF (10 ng/ml)-induced growth of SC-3 cells was abolished only by TGF-beta (greater than or equal to 1 ng/ml) among various growth factors examined. We show for the first time in this study an androgen-dependent growth of cancer cells (SC-3) in a protein-free medium. In the protein-free medium, growth of SC-3 cells is also stimulated by FGFs, and the androgen- or FGF-induced growth is inhibited only by TGF-beta.

Animals↗

PubMedDate not supplied

Experimental induction of uterine adenocarcinoma in rats by estrogen and N-methyl-N-nitrosourea.

To induce uterine endometrial adenocarcinoma, Donryu rats were given subcutaneous injections of 100 micrograms/kg estradiol dipropionate (ED) four times once a week from 3 months old, followed by weekly intraperitoneal injections of 20 mg/kg N-methyl-N-nitrosourea (MNU) four times. In the ED+MNU group, the incidences of marked hyperplasias and adenocarcinomas were higher than those in the control and ED or MNU alone groups, when the incidences were compared in survival cases only up to the age of about 15 months, while the survival rate showed a specially low value of 35% in this group. These results may suggest the possibility of early and high occurrence of uterine adenocarcinoma in this rat strain by estrogen and MNU.

Adenocarcinoma↗

PubMedDate not supplied

A study of effects of WGA and ConA on RBC membrane receptors using a new ektacytometric method.

With a new ektacytometry, we studied the relation between the microstructure of red blood cell (RBC) membrane and the rheological properties of RBCs in a shear flow field of low viscosity. The main contributions of this paper are as follows: 1. The hemorheological meanings of the orientation index (DI)or and the small deformation index (DI)d were explored. (DI)or is an overall rheological index depending on the deformability and morphology of RBCs. The better the physiological shape of RBCs is maintained, the greater the (DI)or is. (DI)d can be used to describe the lipid fluidity of RBC membrane. Such an explanation for the meaning of (DI)d has been forcefully supported by our experiments using electron spin resonance (ESR) and fluorescence polarization. 2. The influence of wheat germ agglutinin (WGA) of different concentrations on the lipid fluidity of membrane is different from that of concanavalin A (ConA). The lipid fluidity of membrane changes with WGA concentration treating RBCs and there is a maximum value for the membrane fluidity at a specific concentration of WGA. However, the deformability of membrane described by the integrate deformation index (IDI) monotonically decreased with the increase in WGA concentration treating RBCs. 3. It is concluded that the increase in the lipid fluidity of red cell membrane is not necessarily associated with the improvement of RBC deformability.

Animals↗

PubMedDate not supplied

Toxicokinetics and biochemistry of cadmium with special emphasis on the role of metallothionein.

Cadmium is a toxic metal with extremely long biological half-time of 15-20 years in humans. It has for decades been known that cadmium exposure can cause a variety of adverse health effects, among which kidney dysfunction, lung diseases, disturbed calcium metabolism and bone effects are most prominent. Following long term exposure the kidney is the critical organ. Cadmium and its compounds give rise to lung cancer after inhalation and have been classified as human carcinogens. Metallothionein (MT) is a low-molecular -weight protein, 6500Da with high cysteine content and high metal affinity, which plays a major role in the kinetics and metabolism of cadmium. The balance between CdMT and non-bound Cd in renal tissue has been shown to be of crucial importance for expression of toxicity. The most well studied metallothioneins are metallothioneins I and II with their isoforms which are expressed in almost all mammalian tissues. Metallothionein III is expressed in brain and is rich in zinc. Since the blood-brain barrier keeps Cd outside the CNS, reported neurotoxic effects of Cd during development are likely to be secondary to an interference of Cd with Zn-metabolism and not a direct effect of Cd on brain cells. It is therefore of importance to investigate whether neurotoxicity induced by cadmium is related to mechanisms involving MT III in brain.

Animals↗