Limited heat-shock protein 72 induction in Caco-2 cells by L-glutamine.

BACKGROUND/AIMS: L-glutamine (L-gln) is a conditionally essential amino acid which is consumed by certain tissues like the intestine in large amounts as energy source during critical illness. Apart from nutritive action, recent data suggest a link to heat-shock protein (hsp) induction. We investigated the effect of L-gln on hsp72 expression in the intestinal cell line Caco-2 under basal and heat-shock conditions and compared it with related amino acids. METHODS: Total cellular protein was extracted and separated by SDS-PAGE. Immunoblots were performed with anti-hsp72 followed by chemiluminescence detection and densitometric scanning. RESULTS: Following heat shock, hsp72 protein expression increased by 72 and 53% at 2 and 4 mmol/l L-gln, respectively, compared to heat shock alone (p < 0.05). Under basal conditions a limited increase occurred only at 8 mmol/l L-gln (p < 0.01). Levels remained unaffected when related amino acids including alanine, glutamate or glycine were supplemented under basal and heat-shock conditions. Similarly, the nonmetabolizable glutamine analogue DON or the toxic metabolite L-pyroglutamate did not induce hsp72. CONCLUSION: We conclude that the glutamine-mediated effect may be specifically attributed to the metabolic action of L-gln.

Cloning and characterization of human erythroid membrane-associated protein, human ERMAP.

We describe here the cloning and characterization of the human gene ERMAP, identified by subtractive hybridization using early and late gestation human fetal liver. By in situ hybridization, we found human ERMAP to be expressed not only in erythoid cells in fetal liver and adult bone marrow, but also in reticulocytes and circulating erythroblasts in 8-12-week fetal cord blood. The human ERMAP protein is predicted to contain a transmembrane segment and one extracellular immunoglobulin fold (IgV). The cytoplasmic region contains a highly conserved B30.2 motif, multiple consensus sequences for kinases, and post-Golgi sorting signals. The protein was localized to the cell surface as shown by an antibody specific for a peptide predicted from the IgV fold. The amino acid sequence of human ERMAP is highly homologous with that of mouse ERMAP, but differs in the number of extracellular immunoglobulin folds. Human ERMAP represents a new unique member of the rapidly growing B30.2 domain proteins.

Evidence against a pivotal role of preformed antibodies in delayed rejection of a guinea pig-to-rat heart xenograft.

INTRODUCTION: Whereas the involvement of elicited xenoantibodies in delayed xenograft rejection is currently being substantiated, this study focuses on the role of the preformed fraction of xenoantibodies. METHODS: To check the influence of the latter, we combined pretransplant complement inactivation (cobra venom factor) and antibody reduction (plasmapheresis) in a guinea pig-to-rat heart transplant model. RESULTS: Antibody reduction on plasmapheresis before xenografting did not prolong delayed xenorejection in decomplemented rats, although the immunohistologic pattern lacked the immunoglobulin deposits along endothelial walls found in xenografts of merely decomplemented recipients. Astonishingly, plasmapheresis, if carried out 2 days before transplantation, almost tripled xenograft survival, although preformed antibody levels were completely restored and even rebounding at the time of grafting. The pattern and number of infiltrating cells did not differ in dependence of the timing of plasmapheresis nor did the proliferative response of lymphocytes in the mixed lymphocyte reaction differ. However, plasmapheresis led to a retarded decrease of the mononuclear cell tumor necrosis factor alpha secretory potential, which correlated well with a diminished immunohistologic staining of tumor necrosis factor alpha secreted by graft-infiltrating mononuclear cells. CONCLUSION: These findings argue against a pivotal role of preformed xenoantibodies in the pathomechanistic process of delayed xenograft rejection and challenge the therapeutic strategy to reduce preformed xenoantibody levels before xenotransplantation in complement-inactivated recipients.

Identification of differentially expressed mRNAs in human fetal liver across gestation.

Differential gene expression, with its precise start and stop times, is believed to be critical for the programmed development of new cells and tissues. Within the developing fetus, one tissue of particular interest is fetal liver. This organ undergoes rapid changes in the pathway toward liver development in utero since it is also the major site of hematopoiesis, until bone marrow hematopoiesis predominates. Believing that patterns would emerge from the bi-weekly large-scale inspection of expressed genes in the fetal liver, we employed differential display reverse transcription-polymerase chain reaction (DDRT-PCR) as ourprimary inspection tool. Using DDRT-PCR, we isolated cDNAs differentially expressed throughout fetal liver development and in adult liver. We displayed approximately 25 000 cDNAs from 10 and 24 week fetal liver and adult liver. From this initial screen, we determined that approximately 0.1-1% of the mRNA population undergoes expression changes. We extracted, purified and sequenced 25 differentially displayed cDNA bands. Fourteen cDNAs had similarities to known genes, while 11 cDNAs were not similar to any characterized gene. The differentially expressed cDNAs from known genes present in fetal liver include alpha-fetoprotein, stem cell factor, erythroid alpha-spectrin, 2,3-bisphosphoglycerate mutase, insulin-like growth factor-2, porphobilinogen deaminase and Mac30. The differentially expressed cDNAs present in adult liver but not in 10 week fetal liver were nicotinamide deaminase, human fibrinogen-related protein and alpha-acid glycoprotein. The majority of differentially expressed genes found during this effort appear to be turned on during organogenesis, however, some genes were found that are apparently turned off completely.

Renal expression of a transforming growth factor-alpha transgene accelerates the progression of inherited, slowly progressive polycystic kidney disease in the mouse.

Polycystic kidney disease (PKD) is a prevalent inherited disease in human beings. The pathogenesis of PKD is as yet unclear. The epidermal growth factor family of proteins has been implicated in PKD based largely on in vitro data. To determine whether these growth factors contribute to the progression of inherited PKD in vivo, we crossed mice with a transgene for human transforming growth factor-alpha (TGF-alpha, a member of the epidermal growth factor (EGF) family) and mice with the pcy gene (which causes a slowly progressive form of PKD very similar to human autosomal dominant PKD). Renal expression of the TGF-alpha transgene in cystic mice (homozygous for the pcy gene) accelerated the development of PKD as shown by an increased kidney weight as a percent of body weight and an increased volume density of renal cysts at 8.5 weeks of age. However, renal expression of the TGF-alpha transgene did not appear to precociously initiate cyst development (at 6.5 weeks), nor did it cause an increase in the final degree of renal enlargement (at 29 weeks). Thus TGF-alpha accelerated the enlargement of cysts once initiated. At 8.5 weeks of age, renal expression of the TGF-alpha mRNA correlated positively with the amount of renal enlargement. At all time points studied, cystic kidneys exhibited increased expression of c-myc mRNA as compared with phenotypic normal kidneys, consistent with PKD being a hyperplastic disease of renal tubules. However, the renal expression of c-myc in 8.5 week cystic kidneys, with or without the transgene, did not correlate with the degree of renal enlargement. The results of this study suggest that EGF-like proteins may accelerate the progression of inherited renal cystic disease. However, the final degree of cystic change is dictated by the primary disease process rather than by the continued presence of growth factor.

Omega-3 lipid infusion in a heart allotransplant model. Shift in fatty acid and lipid mediator profiles and prolongation of transplant survival.

BACKGROUND: omega-3 Fatty acids may have a major impact on immune responses involved in heart transplant rejection. We compared the effects of posttransplant intravenous supplementation with omega-3-rich versus omega-6-rich lipid emulsions on graft survival, plasma fatty acid profiles, and levels of arachidonic acid versus eicosapentaenoic acid-derived lipid mediators. METHODS AND RESULTS: Inbred PVG and Wistar-Kyoto rats were used as donors and recipients, respectively, in a model of heterotopic heart transplantation. Animals received 9 g/kg body wt per day of either fish oil-derived (n = 8) or soybean oil-derived fat (n = 7) in the form of a continuously infused lipid emulsion; controls were sham-infused with saline (n = 8). Graft rejection was assessed by loss of activity of the transplant. The fish oil-derived preparation but not that originating from soybean oil caused an increase in total and free plasma fatty acids. Substantial quantities of eicosapentaenoic acid and docosahexaenoic acid appeared in the free fatty acid fraction, surpassing those of arachidonic acid. Ex vivo stimulation of neutrophils with the Ca2+ ionophore A23187 demonstrated an increase in 5-series leukotriene (LT) generation in animals undergoing omega-3 lipid infusion (LTB5, omega-oxidation products of LTB5, LTA5 secretion), with 5-series/4-series LT ratios ranging between 0.08 and 0.36. Ratios of TX B3/B2 liberated from ex vivo stimulated platelets even approached 1:1 in omega-3 supplemented rats. Graft survival was 7.6 +/- 0.3 (mean +/- SEM) days in saline-infused, 10.4 +/- 0.7 in omega-6 lipid-infused, and 12.9 +/- 0.4 in omega-3 lipid-infused animals. CONCLUSIONS: Posttransplant intravenous alimentation with fish oil-derived lipid emulsions prolongs heart transplant survival in excess to omega-6 lipids. Profound changes in fatty acid profiles and lipid mediator generation may underlie this finding.

Renal cysts in transgenic mice expressing transforming growth factor-alpha.

Transforming growth factor-alpha (TGF-alpha) is a member of the epidermal growth factor (EGF) family of proteins and, like EGF, elicits its cellular function by binding to the EGF receptor. EGF stimulation may have a role in several normal and pathologic processes in the kidney, and EGF has been implicated in the development of renal cysts in vitro and in human autosomal dominant polycystic kidney disease. We sought to determine whether renal expression of an EGF-like protein (TGF-alpha) could lead to the formation of renal cysts in vivo. We examined morphologic alterations to the normal kidney caused by renal expression of a TGF-alpha transgene linked to a mouse metallothionein promoter stably integrated into the genome of the CD1 mouse. TGF-alpha transgene expression was induced with exogenous zinc treatment starting at 4 weeks of age, and mice were killed at 8 weeks of age. The transgene was expressed at higher levels in female transgenic mice than in male transgenic mice. The augmented expression of the TGF-alpha transgene in females was associated with increased renal size and the development of renal epithelial cysts. Both male and female mice exhibited increases in glomerular size and mesangial volume density. These results provide evidence that stimulation by an endogenous EGF-like protein can lead to renal enlargement, glomerular mesangial expansion, and renal cyst formation.

Adsorption of selected organic compounds onto calcium fluoride.

Selected organic compounds adsorb onto CaF2 and can be revealed by staining methods. The possible influence of CaF2 coated with organic compounds on the dissolution rate is discussed.

[Tumor degeneration of an autogenous ovarian transplant]. / Tumoröse Entartung eines autogenen Ovartransplantates.

At a woman, at that time only 27 years old, because of a one-sided ovarian tumour, the abdominal hysterectomy with the resection of both appendages had been carried out. At the same time the other ovary macroscopically without pathological findings had been implanted into the Retzius cavity, where later it degenerated tumourously like the histological picture of a cystoma serosum papilliferum proliferans. Since the resection of the second tumour, which was carried out 28 years after the first operation, there has been found no more manifestation of a tumour up to now.

Calcium fluoride containing granules produced in vitro in rat bones.

Femurs and tibias of normal rats were fixed in 4% unbuffered solutions of glutaraldehyde or formaldehyde containing 1% NaF. Following washing, radiographically controlled demineralization was performed in 3.25% HNO3. Light microscopy and transmission electron microscopy revealed the presence of so-called fluoride granules in bone trabeculae, cartilage, cartilage remnants, bone cells, chondrocytes and in the bone marrow. Selected area diffraction indicated that the fluoride granules contained CaF2. X-ray diffraction analysis of non-demineralized NaF-fixed bones were negative for CaF2. The results are discussed and related to precipitation artifacts reported in demineralized hard tissues and to similar CaF2-containing granules observed in demineralized bones and incisors of rats given high doses of NaF in diet or drinking water.