Isolation, culture, and transplantation of rat hepatocytic precursor (stem-like) cells

From a review of past studies and the report of new studies from our laboratory, this article provides strong evidence to show that WB-F344 (WB) rat liver epithelial cells are stem-like precursor cells for hepatocytes. WB cells are structurally and phenotypically simple epithelial cells that were isolated from the liver of an adult male Fischer 344 rat, under conditions that excluded their origin from hepatocytes in vivo. WB cells express a phenotypic repertory that overlaps, but is distinct from, that of both hepatocytes and bile duct epithelial cells. The complex phenotype of WB cells is compatible with their being embryonic or undifferentiated variants of either hepatocytes or bile duct epithelial cells. When WB cells are tagged genetically with genes for bacterial beta-galactosidase and neomycin resistance (BAG2-WB), they and their progeny can be distinguished from parental WB cells and hepatocytes by the expression of these gene products. Progeny of BAG2-WB cells that were transplanted into the liver parenchyma of syngeneic rats integrated into hepatic plates and acquired the morphological and functional attributes of adjacent host hepatocytes; the progeny of BAG2-WB cells in the liver express albumin, tyrosine aminotransferase, alpha-1-antitrypsin, and transferrin. We also demonstrate that progeny of BAG2-WB cells can be recovered from livers into which they have been transplanted, which may allow the elucidation of alterations in gene expression that accompany their differentiation.

Diethylnitrosamine- and partial hepatectomy-induced decrease in alpha 2u-globulin mRNA level in the rat liver

Changes in gene expression in the rat liver were investigated by analyzing cDNA libraries for liver mRNAs from adult male rats injected with a chemical carcinogen diethylnitrosamine (DEN). Differential screening using normal and DEN-treated liver cDNAs as probes demonstrated that some of the mRNA species had noticeably lower abundance in the DEN-treated liver than in the untreated liver. Surprisingly, most of those clones were found to code for alpha 2u-globulin (A2uG), an abundant protein in the male rat liver. Further analysis by in situ hybridization revealed that the decrease in the A2uG mRNA level occurred in the area where liver cells were proliferating due to DEN treatment and/or partial hepatectomy (PH). The findings indicate coincidence of cell proliferation with a decrease in the A2uG gene expression in the adult male rat liver, implying that the A2uG-related change favors chemical carcinogen-induced cell growth.

Defense mechanisms in alcoholics attending outpatient treatment. Results from the MCT-test (Meta-Contrast Technique)

Defensive strategies were studied in 72 alcoholics participating in outpatient treatment by using, before the treatment started, the Meta-Contrast Technique, MCT, a percept-genetic method. Alcoholics had less often adaptive strategies than controls. A lack of adaptive defense strategies was related to a more impaired psychic status, more psychological benefits from drinking, and more psychiatric symptoms but not to severity of alcoholism or results of psychometric tests (intellectual level, field-dependence, spatial performance). It does not seem inconceivable that the MCT could be used as a diagnostic tool in treatment planning.

Effects on heterozygosity and reproductive fitness of inbreeding with and without selection on fitness in Drosophila melanogaster

The effects of inbreeding, with (IS) and without selection (IO) for reproductive fitness, on inbreeding depression and heterozygosity were evaluated in 20 lines of each treatment inbred over seven generations using full-sib mating. The survival of lines was significantly greater in IS (20/20) than in IO (15/20). The competitive index measure of reproductive fitness was significantly lower in the inbred lines than in the outbred base population, but not significantly different in surviving IS and IO lines. There was a trend for higher fitness in the IS treatment as relative fitnesses were 19% higher in IS than IO for surviving lines and 59% higher for all lines. Heterozygosities were lower in the inbred lines than in the base population, and significantly higher in the IS than the IO lines. Consequently, the reduction of inbreeding depression in IS has been achieved, at least in part, by slowing the rate of fixation.

Identification of human DNA in complex biological samples using the Alu polymerase chain reaction

Alu-Polymerase chain reaction (PCR) was used to amplify human DNA from complex mixed sources of DNA. Amplification of human DNA sequences by Alu-PCR could be accomplished in samples containing low concentrations of template in the presence of excess heterologous DNA sequences. Thus, sensitivity and specificity are maintained in complex DNA mixtures allowing positive identification of the presence of human DNA sequences by this technique.

Improved ultrastructural lung preservation with prostaglandin E1 as donor pretreatment in a primate model of heart-lung transplantation

Donor pretreatment with prostaglandin E1 as a pulmonary vasodilator has developed as a simple, effective means to provide excellent preservation in heart-lung transplantation. This study was undertaken to investigate the degree of ultrastructural preservation of the lung with prostaglandin E1 and other pulmonary vasodilators in a primate heart-lung transplantation model. Heart-lung transplantation was performed in 14 African green monkeys. Donor cardiac preservation was achieved with cold crystalloid cardioplegic solution (10 ml/kg). Lung preservation was achieved with cold, modified Euro-Collins solution delivered into the main pulmonary artery (60 ml/kg total). Vasodilator agents were administered intravenously 15 minutes before aortic crossclamping. The heart-lung grafts were stored at 4 degrees C for 6 hours. Three groups of animals were studied: five donors with prostaglandin E1 (0.1 to 4.0 micrograms/kg per minute), five donors with prostacyclin (0.1 to 0.35 micrograms/kg per minute), and four donors with nitroprusside (0.8 to 5.0 micrograms/kg per minute). After transplantation, arterial blood gas measurements and lung biopsies were performed at 1- and 3-hour intervals. Five formalin blocks per specimen were sectioned for hematoxylin and eosin staining. Cellular preservation and endothelial cell swelling were evaluated with electron microscopy. The specimens were graded for alveolar hemorrhage, endothelial cell swelling, and cellular preservation (grade 0, minimal, to grade 3, severe) and a mean score was obtained for each preservative agent. Prostaglandin E1-treated specimens demonstrated the least amount of endothelial swelling (mean score of 1.0) compared with prostacyclin- and nitroprusside-treated specimens (mean scores of 1.4 and 2.7, respectively). All nitroprusside-treated specimens demonstrated moderate to severe endothelial cell swelling. Interstitial and alveolar hemorrhage was noted in poorly preserved specimens, but there were no significant differences between groups. We conclude that prostaglandin E1 provides improved cellular preservation by decreasing the extent of endothelial cell swelling as observed on electron microscopy.

The photophysics of haematoporphyrin dimers or aggregates in aqueous solution

The triplet lifetime and decay rate law observed from haematoporphyrin in aqueous solution were found to depend on concentration with the triplet-state decay being very much slower in dilute solution than in more concentrated solutions. The wavelength of excitation also has an effect on the decay kinetics. In a 1 x 10(-4) mol dm-3 solution the decay resulting from flash photolysis at 527 nm is satisfactorily described by a single exponential having a decay constant of 1.5 x 10(4) S-1 and was ascribed to the triplet state of a haematoporphyrin dimer or aggregate. However, excitation of a haematoporphyrin solution of the same concentration at 351 nm results in a slower triplet-state decay which is indistinguishable, within experimental error, from that observed from a dilute haematoporphyrin solution excited at 527 nm and which is ascribed to the monomer triplet state. Although resolved Soret band absorption spectra indicate that in a 1 x 10(-4) mol dm-3 aqueous solution of haematoporphyrin most radiation at 351 nm is absorbed by a dimer, the decay following flash photolysis at 351 nm is dominated by the triplet state of the haematoporphyrin monomer. This implies that the excited singlet state of the dimer whose ground state absorbs the shorter-wavelength region of the Soret band undergoes efficient intersystem crossing to the monomer triplet state.(ABSTRACT TRUNCATED AT 250 WORDS)

Confocal laser scanning immunofluorescence microscopy of the pulmonary surfactant system. Association of surfactant protein A with the nucleus of the alveolar type II cell

BACKGROUND

Localization of surfactant protein A (SP-A) to nucleus of type II cells isolated from the lungs of rats has been reported. Data suggested that most SP-A was located within lamellar bodies of the type II cell; however, some SP-A was found in other cytoplasmic regions of the cell and in particular in the nucleus.

EXPERIMENTAL DESIGN

Type II cells and type II cell nuclei isolated from the lungs of rats were reacted with affinity-purified antibodies against SP-A. Location of SP-A was determined by using fluorescein isothiocyanate-labeled secondary antibodies and the distribution of fluorescence examined by using a laser scanning microscope fitted with a confocal aperture. Two-dimensional electrophoresis followed by Western blotting was used to separate and identify type II cell nuclear proteins.

RESULTS

Nuclei were isolated from type II cells obtained from elastase-digested rat lungs and examined for the presence of SP-A. The nuclei contained both focal and diffuse deposits of SP-A. Some regions within the nuclear matrix (in particular the nucleolus) appeared to be relatively devoid of SP-A. The perinuclear membrane stained intensely for SP-A where optical sectioning showed its presence as a patchwork of punctate deposits. Analysis of the SP-A associated with the nucleus by two-dimensional electrophoresis revealed that it consisted of a family of proteins with molecular masses of 26, 32, and 36 kDa and pI 5.1. Biosynthesis of nuclear SP-A in primary cultures of type II cells was sensitive to inhibitors of glycosylation resulting in the presence of only the lowest molecular weight unprocessed form.

CONCLUSIONS

These data indicate that three basic forms of SP-A are associated with the nucleus of the type II cell and are especially concentrated on the perinuclear membrane.

Regulation of the differentiation of diploid and some aneuploid rat liver epithelial (stemlike) cells by the hepatic microenvironment

Following intrahepatic transplantation in adult syngeneic Fischer 344 rats, diploid cultured rat liver epithelial cells (WB-F344), modified to carry the Escherichia coli beta-galactosidase reporter gene and/or the fluorescent membrane dye PKH26-GL, integrate into hepatic plates and acquire the size and nuclear structure of mature hepatocytes. Additionally, of two aneuploid, neoplastically transformed derivatives of WB-F344 cells, both of which produce aggressively growing tumors when transplanted subcutaneously, cells of one line (GN6TF) do not produce tumors in the liver but integrate into hepatic plates and morphologically differentiate. The other transformed line (GP7TB) retains tumorigenicity in the liver, but cells in the intrahepatic tumors are more differentiated morphologically than are tumors at subcutaneous sites. These results suggest that WB-F344 cells are stemlike cells for hepatocytes and that the hepatic microenvironment induces them to incorporate into hepatic plates and differentiate. Our results also suggest that the hepatic microenvironment regulates the differentiation of some neoplastically transformed hepatic stemlike cells, thereby eliminating or reducing their tumorigenic potential.

Seasonal trends in erythemal and carcinogenic ultraviolet radiation at mid-southern latitudes 1989-1991

A network of solar carcinogenic/erythemal ultraviolet radiometers has been established in New Zealand. Daily integrated irradiances of this biologically harmful ultraviolet radiation for 1989, 1990 and 1991 are reported from radiometers located at Wellington (41 degrees S) and Christchurch (43.5 degrees S) and for 1990 and 1991 from the Auckland (37 degrees S) radiometer. Although the monitoring program has not been running sufficiently long to discern any long-term changes in levels of solar ultraviolet radiation, shorter term trends are apparent, which are attributed to a seasonal cycle in levels of ozone at midlatitudes and changes in atmospheric aerosols.

Pulmonary artery balloon counterpulsation: safe after peripheral placement

Pulmonary artery balloon counterpulsation is a promising experimental technique for treatment of right ventricular failure. However, clinical application has been limited in that the only device presently available (the large-volume intraaortic balloon) must be placed within a synthetic graft. Because a balloon with a smaller volume (which could be placed through a peripheral vein and be contained entirely within the pulmonary artery) would make the technique feasible on a wider scale, we tested an 8-mL pulmonary artery balloon placed through the femoral vein in 12 dogs. Two groups of animals were compared. One group had the pulmonary artery balloon in place but not counterpulsating; the other had the pulmonary artery balloon in place and counterpulsating. Each group was studied for 12 hours. A variety of hemodynamic parameters were measured. Effective diastolic augmentation and systolic unloading were noted in all 6 dogs that underwent counterpulsation (5.0 +/- 1.1 mm Hg of diastolic augmentation and 9.5 +/- 1.6 mm Hg of systolic unloading). Pulmonary function, as measured by arterial blood gas sampling and pulmonary vascular resistance, was not impaired. Examination of the heart and lungs showed no detrimental pathologic effects of pulmonary artery balloon counterpulsation. Placement of the balloon through a peripheral vein with a guidewire was easy and uncomplicated. We conclude that pulmonary artery balloon counterpulsation is safe over an extended period of 12 hours in the canine model and that diastolic augmentation and systolic unloading can be produced.

Clonal analysis of the expression of multiple transformation phenotypes and tumorigenicity by morphologically transformed 10T1/2 cells

Seventy-five clonal populations of morphologically transformed 10T1/2 cells were established from independent Type II and Type III foci that were of spontaneous origin or were induced by the carcinogenic agents N-methyl-N'-nitro-N-nitrosoguanidine, benzo(a)pyrene diol epoxide-I, and 3-methylcholanthrene. Clonal populations were characterized for expression of selected transformation phenotypes, including growth to elevated saturation density before cessation of proliferation, anchorage independence, ability to reconstruct foci when plated in the presence of wild-type 10T1/2 cells, and tumorigenicity. Forty-one % of the clonal populations expressed only the phenotype of morphological transformation, while 20% expressed all of the transformation phenotypes, including tumorigenicity, in addition to morphological transformation. The remaining clonal populations expressed varying combinations of one or more of the four transformation phenotypes. Clonal populations expressing almost all of the 16 possible combinations of the transformation phenotypes were observed, suggesting that the individual phenotypes segregated independently. Morphological transformation alone was a poor indicator of tumorigenicity, correctly predicting the tumorigenic potential of only 37% of the clonal populations. Among morphologically transformed clonal populations, coexpression of anchorage independence correctly predicted the tumorigenicity of 81% and coexpression of reconstruction of foci on a confluent lawn of wild-type cells correctly predicted the tumorigenicity of 91%. The probability that a morphologically transformed clonal population was tumorigenic correlated with the total number of transformation phenotypes expressed. Expression of the transformation phenotypes differed between tumorigenic and nontumorigenic clonal populations but not between clonal populations established from Type II and Type III foci. Tumorigenicity varied among transformed clonal populations that were induced by the different carcinogenic agents or were of spontaneous origin but did not differ between clonal populations established from Type II and Type III foci.

Intraoperative autotransfusion in hepatic resection for malignancy. Is it safe?

To evaluate whether intraoperative autologous transfusion increases the risk of hematogenous dissemination of tumor we reviewed the risk of lung metastasis as well as disease-free and long-term survival of patients who underwent resection of malignant hepatic neoplasms with this technique. A retrospective review of patients undergoing liver resection for malignant disease revealed 39 patients in whom intraoperative autologous transfusion was used. The 2-year actuarial survival in the patients in this series, as calculated with the Kaplan-Meier method, was predicted to be 75%. Two-year actuarial disease-free survival was predicted to be 28%, and the risk of developing lung metastasis at 3 years was estimated to be 40%. The predicted overall survival and risk of recurrence in this series compare favorably with published data for patients in whom intraoperative autologous transfusion was not used.

Flow cytometric analysis of xenobiotic metabolism activity in isolated rat hepatocytes

Flow cytometry offers great potential for the study of xenobiotic metabolism in intact cells. We explored this application by the use of ethoxyfluorescein ethyl ester (EFEE) and isolated rat hepatocytes, a classic system for studying such reactions. EFEE is only weakly fluorescent and it diffuses freely into viable cells, where it is metabolized to fluorescein by a process dependent upon mixed-function oxidase activity. In the current study, viable hepatocytes were first identified by flow cytometric assessment of fluorescein diacetate staining. The viable subpopulation was also identifiable on the basis of forward and right angle light scattering properties alone, and it was in this fraction that EFEE metabolism was measured. Metabolism of EFEE to fluorescein was quantified by flow cytometry. SKF 525A, alpha-naphthoflavone, and metyrapone, classic inhibitors of mixed-function oxidation, each inhibited the metabolism of EFEE. These results demonstrate the potential of EFEE for use in flow cytometric studies of drug metabolism, such as in multiparameter mechanistic assays of cellular xenobiotic metabolism and toxicity, and in the isolation by fluorescence-activated cell sorting of subpopulations which differ in this activity.

Relaxation and quenching of the excited states of tryptophan in keratin

The temperature dependence of the fluorescence and phosphorescence originating from tryptophan residues in the solid protein keratin was studied. The position of the tryptophan fluorescence spectral maximum was measured as a function of temperature and was found to be substantially Stokes shifted even at 77 K. The activation energies for non-radiative relaxation of the singlet and triplet states of tryptophan in wool keratin, derived from Arrhenius plots of the fluorescence and phosphorescence yields, are 580 cm-1 and 995 cm-1 respectively. One possible fluorescence quenching mechanism which is consistent with these observations is a very effective, thermally induced mixing of the 1La and 1Lb excited singlet states which results in enhanced internal conversion apparent as a low fluorescent yield even at low temperatures. The phosphorescence decay from keratin in the absence of oxygen following excitation at 265 nm is non-single exponential. At room temperature it is dominated by a short-lived component with more than 80% of the decay completed within 3 microseconds of the flash. Longer living components with first-order lifetimes as long as 2-3 s were also observed.

A simple technique for the determination of kappa and lambda immunoglobulin light chain expression by B cells in whole blood

This article describes the development of a simple technique by which the numbers of surface immunoglobulin expressing cells can be analysed by dual fluorescence flow cytometry in samples of whole blood. We have compared the results obtained using this procedure with those obtained using samples prepared by traditional density gradient centrifugation, and demonstrate an excellent correlation between the two techniques. The method is applicable both to blood samples from normal individuals and from patients with B cell malignancies such as B-CLL and B-NHL. We have also confirmed previous findings that density gradient centrifugation may preferentially deplete certain lymphocyte subsets. This technique offers the following advantages: (i) it is rapid, (ii) it is accurate, (iii) it is reliable, (iv) it is useful in cases of lymphopenia, and (v) it requires only a small volume of blood. It is likely to be applicable to other situations in which the presence of serum factors interfere with antibody staining in whole blood.

Partial characterization of nuclear matrix attachment regions from human fibroblast DNA using Alu-polymerase chain reaction

The proteinaceous nuclear matrix of mammalian cell nuclei has been suggested to be involved in the regulation of chromatin structure, DNA replication, and gene expression. Interaction between cellular DNA and the nuclear matrix is mediated by putative DNA binding sequences, matrix attachment regions (MARs), which may become altered during early events in cellular transformation. Among the cellular changes occurring during the development of neoplasia, all of which may potentially involve the nuclear matrix, are alterations in nuclear structure, loss of control of DNA replication, and significant modifications of cellular gene expression. Therefore, a better understanding of the interaction between DNA and the nuclear matrix is needed. Isolated matrix associated DNA from pulse labeled SV40 transformed human fibroblasts was shown to be enriched in newly replicated DNA, confirming the association of DNA replication with the nuclear matrix as observed by others. Subgenomic fractions of matrix associated DNA enriched in putative MARs sites were prepared from quiescent and logarithmically growing normal human fibroblasts and SV40 transformed human fibroblasts. These fractions of DNA were analyzed by Alu-polymerase chain reaction and agarose gel electrophoresis, revealing complex and unique patterns of DNA products for each cell type investigated. A number of prominent DNA fragments with similar molecular size were found to be present in the amplified DNA products of each DNA source, suggesting that these DNA fragments may represent common DNA sequences which contain MARs sites or which are associated with MARs sites. The application of Alu-polymerase chain reaction to the molecular analysis of nuclear matrix associated DNA may facilitate the isolation and characterization of potentially new human MARs sequences.

Altered levels and protein kinase C-mediated phosphorylation of substrates in normal and transformed mouse lung epithelial cells

Protein phosphorylation and protein kinase C (PKC) levels were analyzed in intact cultures of spontaneously transformed, chemically transformed, and untransformed mouse pulmonary epithelial cell lines. It was found that although the transformed cell lines contained about 80% less protein kinase C, measured as total enzyme activity or binding of [3H]phorbol ester, phosphorylation events after phorbol ester treatment could still be easily detected. A commonly described Mr 80-kDa protein kinase C substrate (p80, 80 K, MARKS) was identified using 2D-PAGE, following phosphorylation in intact cells, and found to have reduced availability for phosphorylation in the transformed cell lines C4SE9, C1SA5 and NULB5 in comparison to the untransformed C4E10 and C1C10. Available levels of p80 were further analyzed in heat-denatured extracts from all cell lines using partially purified bovine brain PKC and correlated well with changes seen in intact cells. It was also noted that all transformed cell lines contained large amounts of a family of phosphoproteins of Mr 55-65 kDa, that could not be detected in the untransformed cell lines and whose phosphorylation state was increased by protein kinase C activation. This protein was found to be located in the nucleus. Hence, spontaneously and chemically transformed mouse pulmonary epithelial cells exhibit reduced levels of PKC, along with an altered pattern of PKC-mediated phosphorylation.

Reduction of graft-versus-host reactivity after small bowel transplantation: ex vivo treatment of intestinal allografts with an anti-T cell immunotoxin

A specific T lymphocyte immunotoxin was used to pre-treat small bowel grafts in an attempt to prevent graft-versus-host (GVH) reactivity and GVH disease in a rat transplant model. The immunotoxin used was a conjugate of the anti-CD5 MoAb MRC OX-19 with ricin A chain. The grafts were perfused ex vivo with a standard solution of immunotoxin followed by incubation at 4 degrees C for 1 h before transplantation. In a semi-allogeneic strain combination (parent to F1 hybrid offspring) graft treatment with immunotoxin led to a prolongation of recipient survival compared with groups receiving similar transplants without immunotoxin treatment. An additive effect on survival was observed when the host was treated with cyclosporin. The effect of immunotoxin was greater than that of mesenteric lymphadenectomy in increasing host survival. The effect of graft treatment with the immunotoxin on cellular migration from graft to host lymphoid tissues was assessed in fully allogeneic transplantation (PVG to DA). Host lymphoid tissues were subjected to immunohistochemical analysis using a MoAb specific for donor class I MHC antigens. Graft treatment with the immunotoxin led to a significant decrease in the number of graft cells found in host lymphoid tissues 7 days after transplantation. However, this effect was less marked than that achieved by graft mesenteric lymphadenectomy. With our current protocol graft treatment with a specific T cell immunotoxin can significantly reduce but not abolish GVH reactivity in rat small bowel transplantation.

Cancer cell motility-inhibitory protein in the Dunning adenocarcinoma model

Cell motility has been associated with metastatic ability in the Dunning R3327 rat prostatic adenocarcinoma model. Cancer cell motility promoters but not inhibitors have been described by many investigators. Serum-containing and serum-free media conditioned by the nonmotile, nonmetastatic G Dunning subline inhibited the motility of the highly motile, highly metastatic MAT-LyLu subline. Motility inhibition by the G subline-conditioned serum-free media was lost upon heating to 100 degrees C and by treatment with trypsin. The motility inhibitory protein(s) had a molecular weight exceeding 50,000 as determined by diafiltration. G subline-conditioned RPMI 1640 contained several proteins with molecular weights of between approximately 53,000 and 116,000 when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. One of these bands may represent the first inhibitor of cancer cell motility identified.

Ex vivo perfusion of intestinal allografts with anti-T cell monoclonal antibody/ricin A chain conjugates for the suppression of graft-versus-host disease

The removal of T lymphocytes from intestinal allografts prior to transplantation would prevent graft-versus-host disease and might also weaken the unusually severe rejection response mounted by graft recipients. Ex vivo perfusion by monoclonal antibody-toxin conjugates represents a potentially ideal approach to achieve this goal. Monoclonal antibody-toxin conjugates were prepared by coupling the mouse anti rat CD5 antibody MRC OX19 to the A chain of ricin. The resultant conjugate contained 1 or 2 ricin A chain molecules per molecule of immunoglobulin and had high selective toxicity for rat T lymphocytes. Following ex vivo perfusion of the small intestine, the mesenteric lymph nodes and Peyer's patches were removed and the level of penetration of the MRC OX19 antibody was assayed by immunohistological techniques. In lymph nodes, there was ready access of the antibody to the medulla, and to a lesser extent to the B cell areas of the cortex. However, only the T cells in the peripheral regions of the paracortex were stained, suggesting that the paracortex was resistant to penetration by blood-borne antibody, and was being stained only by diffusion from the lymph node medulla. Some penetration of the antibody also occurred in the immediate vicinity of the postcapillary venules. In the Peyer's patches, staining was seen in the germinal centers, but not at all in the T cell areas. The addition of agents such as histamine to the perfusate to increase vascular permeability did not alter this picture. These studies suggest the presence of a potentially interesting resistance to penetration of the paracortex of the lymph node by blood-borne substances. Nevertheless, sufficient penetration occurred to influence favorably the course of GVD disease following ex vivo perfusion prior to transplantation of the donor intestine with the MRC OX19-ricin A chain conjugate.

An ultrastructural study of hydrogen peroxide production by cultured fetal and neonatal rat lung cells exposed to hyperoxia

Hydrogen peroxide production in organotypic cultures of fetal and newborn rat lung cells has been investigated using an ultrastructural histochemical method, in which the quantity and location of an electron-dense reaction product derived from the interaction of cerium chloride and hydrogen peroxide was detected. Hydrogen peroxide was present in fetal cell cultures exposed to hyperoxia (50% oxygen) compared to controls maintained in 10% oxygen. This increase could be limited by incubation of cultures with ascorbic acid and preincubation with dexamethasone. On the other hand, in newborn rat lung cell cultures, less hydrogen peroxide was identified in cultures including those exposed to hyperoxia (50% oxygen).

Bile acids influence the growth, oestrogen receptor and oestrogen-regulated proteins of MCF-7 human breast cancer cells

The effects of the major human serum bile acid, glycochenodeoxycholic acid (GCDC), as well as unconjugated chenodeoxycholic acid (CDC), on the MCF-7 human breast cancer cell line have been studied in vitro under oestrogen and bile acid deprived culture conditions. GCDC increased the growth of the breast cancer cells over the range 10-300 microM. At concentrations in excess of the bile acid binding capacity of the medium cell growth was prevented. In contrast 10 microM CDC tended to reduce cell growth. Oestrogen (ER) and progesterone (PgR) receptors, pS2 and total cathepsin D were quantified by monoclonal antibody based immunoassays. Ten to 100 microM GCDC and 10 microM CDC down-regulated ER protein and this was accompanied by induction of the oestrogen-regulated proteins PgR, pS2 and possibly cathepsin D, including increased secretion of the latter two proteins into the culture medium. All these changes were quantitatively similar to those observed with 10 nM oestradiol. The bile acid effects on ER and PgR were not due to interference with the assay procedures. Cells incubated with 50 microM GCDC or 10 microM CDC had higher pmolar concentrations of the bile acids than controls. This study suggests that naturally occurring bile acids influence the growth and steroid receptor function of human breast cancer cells.