Alternative splicing, promoter methylation, and functional SNPs of sperm flagella 2 gene in testis and mature spermatozoa of Holstein bulls

The sperm flagella 2 (SPEF2) gene is essential for development of normal sperm tail and male fertility. In this study, we characterized first the splice variants, promoter and its methylation, and functional single-nucleotide polymorphisms (SNPs) of theSPEF2gene in newborn and adult Holstein bulls. Four splice variants were identified in the testes, epididymis, sperm, heart, spleen, lungs, kidneys, and liver tissues through RT-PCR, clone sequencing, and western blot analysis. Immunohistochemistry revealed that theSPEF2was specifically expressed in the primary spermatocytes, elongated spermatids, and round spermatids in the testes and epididymis.SPEF2-SV1was differentially expressed in the sperms of high-performance and low-performance adult bulls;SPEF2-SV2presents the highest expression in testis and epididymis;SPEF2-SV3was only detected in testis and epididymis. An SNP (c.2851G>T) in exon 20 ofSPEF2, located within a putative exonic splice enhancer, potentially producedSPEF2-SV3and was involved in semen deformity rate and post-thaw cryopreserved sperm motility. The luciferase reporter and bisulfite sequencing analysis suggested that the methylation pattern of the core promoter did not significantly differ between the full-sib bulls that presented hypomethylation in the ejaculated semen and testis. This finding indicates that sperm quality is unrelated toSPEF2methylation pattern. Our data suggest that alternative splicing, rather than methylation, is involved in the regulation ofSPEF2expression in the testes and sperm and is one of the determinants of sperm motility during bull spermatogenesis. The exonic SNP (c.2851G>T) produces aberrant splice variants, which can be used as a candidate marker for semen traits selection breeding of Holstein bulls.

Effects of chromium picolinate on the viability of chick embryo fibroblast

Chromium picolinate (CrPic), which is used as a nutritional supplement and to treat type 2 diabetes, has gained much attention because of its cytotoxicity. This study evaluated the effects of CrPic on the viability of the chick embryo fibroblast (CEF) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, morphological detection, and flow cytometry. The results show that lower concentrations of CrPic (8 and 16 μM) did not damage CEF viability ( p > 0.05). However, higher CrPic concentrations (400 and 600 μM) indicated a highly significant effect on the production of intracellular reactive oxygen species, alteration of mitochondrial membrane potential, intracellular calcium ion concentration, and the apoptosis rate ( p < 0.01), contrary to lower CrPic concentrations (8 and 16 μM) and control group. Moreover, apoptotic morphological changes induced by these processes in CEF were confirmed using Hoechst 33258 staining. Cell death induced by higher concentrations of CrPic was caused by an apoptotic and a necrotic mechanism, whereas the main mechanism of oxidative stress-induced mitochondrial dysfunction was apoptotic death.

Signatures of the Z = 82 shell closure in α-decay process

In recent experiments at the velocity filter Separator for Heavy Ion reaction Products (SHIP) (GSI, Darmstadt), an extended and improved set of α-decay data for more than 20 of the most neutron-deficient isotopes in the region from lead to thorium was obtained. The combined analysis of this newly available α-decay data, of which the (186)Po decay is reported here, allowed us for the first time to clearly show that crossing the Z = 82 shell to higher proton numbers strongly accelerates the α decay. From the experimental data, the α-particle formation probabilities are deduced following the Universal Decay Law approach. The formation probabilities are discussed in the framework of the pairing force acting among the protons and the neutrons forming the α particle. A striking resemblance between the phenomenological pairing gap deduced from experimental binding energies and the formation probabilities is noted. These findings support the conjecture that both the N = 126 and Z = 82 shell closures strongly influence the α-formation probability.

Investigation of interactions between two monoclonal antibodies and SARS virus with a Label-free Protein Array

The investigation of interactions between two kinds of monoclonal antibodies and SARS virus with a label-free protein array technique were presented in this paper. The performance consists of three parts: a surface modification for ligand immobilization/surface, a protein array fabrication with an integrated microfluidic system for patterning, packaging and liquid handling, and a protein array reader of imaging ellipsometer. This revealed the technique could be used as an immunoassay for qualitative and quantitative detection as well as kinetic analysis of biomolecule interaction.

Neuroprotection of neurotrophin-3 against focal cerebral ischemia/reperfusion injury is regulated by hypoxia-responsive element in rats

Exogenous delivery of the neurotrophin-3 (NT-3) gene may provide a potential therapeutic strategy for ischemic stroke. To investigate the neuroprotective effects of NT-3 expression controlled by 5HRE after focal cerebral ischemia, we constructed a recombinant retrovirus vector (RV) with five copies of hypoxia-responsive elements (5HRE or 5H) and NT-3 and delivered it to the rat brain. Three groups of rats received RV-5H-NT3, RV-5H-EGFP or saline injection. Three days after gene transfer, the rats underwent 90min of transient middle cerebral artery occlusion (tMCAO), followed by 1-28days of reperfusion. Three days after tMCAO, brain NT-3 expression was significantly increased in the RV-5H-NT3-transduced animals compared with the RV-5H-EGFP or saline group, and brain infarct volume was smaller in the RV-5H-NT3-transduced group than the RV-5H-EGFP or saline group. The percentage of TUNEL-positive cells was reduced in RV-5H-NT3-transduced brains compared with the RV-5H-EGFP or saline group 3 and 7days after tMCAO. Furthermore, the neurological status of RV-5H-NT3-transduced rats was better than that of RV-5H-EGFP- or saline-transduced animals from 1day to 4weeks after tMCAO. Our results demonstrated that 5HRE could modulate NT-3 expression in the ischemic brain environment and that the up-regulated NT-3 could effectively improve neurological status following tMCAO due to decreased initial damage. To avoid unexpected side effects, 5HRE-controlled gene expression might be a useful tool for gene therapy of ischemic disorders in the central nervous system.

Anxiety-related behavioral inhibition in rats: a model to examine mechanisms underlying the risk to develop stress-related psychopathology

Behavioral inhibition (BI) is an adaptive defensive response to threat; however, children who display extreme BI as a stable trait are at risk for development of anxiety disorders and depression. The present study validates a rodent model of BI based on an ethologically relevant predator exposure paradigm. We show that individual differences in rat BI are stable and trait-like from adolescence into adulthood. Using in situ hybridization to quantify expression of the immediate early genes homer1a and fos as measures of neuronal activation, we show that individual differences in BI are correlated with the activation of various stress-responsive brain regions that include the paraventricular nucleus of the hypothalamus and CA3 region of the hippocampus. Further supporting the concept that threat-induced BI in rodents reflects levels of anxiety, we also show that BI is decreased by administration of the anxiolytic, diazepam. Finally, we developed criteria for identifying extreme BI animals that are stable in their expression of high levels of BI and also show that high BI (HBI) individuals exhibit maladaptive appetitive responses following stress exposure. These findings support the use of predator threat as a stimulus and HBI rats as a model to study mechanisms underlying extreme and stable BI in humans.

Evidence for a spin-aligned neutron-proton paired phase from the level structure of (92)Pd

Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing, in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus (92)Pd. Gamma rays emitted following the (58)Ni((36)Ar,2n)(92)Pd fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution γ-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction. We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.

Detection of hepatitis B virus markers using a biosensor based on imaging ellipsometry

A biosensor based on imaging ellipsometry (BIE) has been developed and validated in 169 patients for detecting five markers of hepatitis B virus (HBV) infection. The methodology has been established to pave the way for clinical diagnosis, including ligand screening, determination of the sensitivity, set-up of cut-off values (CoVs) and comparison with other clinical methods. A matrix assay method was established for ligand screening. The CoVs of HBV markers were derived with the help of receiver operating characteristic curves. Enzyme-linked immunosorbent assay (ELISA) was the reference method. Ligands with high bioactivity were selected and sensitivities of 1 ng/mL and 1 IU/mL for hepatitis B surface antigen (HBsAg) and surface antibody (anti-HBs) were obtained respectively. The CoVs of HBsAg, anti-HBs, hepatitis B e antigen, hepatitis B e antibody and core antibody were as follows: 15%, 18%, 15%, 20% and 15%, respectively, which were the percentages over the values of corresponding ligand controls. BIE can simultaneously detect up to five markers within 1 h with results in acceptable agreement with ELISA, and thus shows a potential for diagnosing hepatitis B with high throughput.

Universal decay law in charged-particle emission and exotic cluster radioactivity

A linear universal decay formula is presented starting from the microscopic mechanism of the charged-particle emission. It relates the half-lives of monopole radioactive decays with the Q values of the outgoing particles as well as the masses and charges of the nuclei involved in the decay. This relation is found to be a generalization of the Geiger-Nuttall law in alpha radioactivity and explains well all known cluster decays. Predictions on the most likely emissions of various clusters are presented.

Phytotherapy versus hormonal therapy for postmenopausal bone loss: a meta-analysis

This meta-analysis included 14 randomized controlled trials involving 780 patients to compare phytotherapy with hormonal therapy in the treatment of postmenopausal bone loss. Current evidence suggests that phytotherapy may possess a similar effect on bone mineral density (BMD) values but clinically is not associated with a high incidence of uterine bleeding and breast pain as is hormonal therapy. Clinical trials indicate that phytotherapy may be a potential treatment for postmenopausal osteoporosis. The objective of this meta-analysis was to compare the efficacy and safety of phytotherapy with that of hormonal therapy, to assess the quality of phytotherapy trials, and to identify herbs used commonly in the treatment of postmenopausal bone loss. A total of 43 electronic databases were searched. The quality of eligible trials was assessed using Jadad's scale. Outcome measures were BMD values and adverse events. Revman 5.0 software was used for data syntheses and meta-analyses. The database search revealed 14 randomized controlled trials involving 780 patients that met the inclusion criteria, and four trials were graded as high quality (score 3-5). There was no significant difference in lumbar, femoral or forearm BMD values between subjects treated with phytotherapy and those treated with hormonal therapy (P>0.05), but the incidence of uterine bleeding and breast pain was significantly lower in those treated with phytotherapy than in those treated with hormonal therapy (P = 0.002 and P = 0.01). The six most commonly used herbs in the included trials were identified. Phytotherapy may not show effects beyond hormonal therapy, but may be safer than hormonal therapy in the treatment of postmenopausal bone loss. Further trials with high-quality study designs should be conducted in this field.

Predator stress induces behavioral inhibition and amygdala somatostatin receptor 2 gene expression

Psychological stressors precipitate and maintain stress-induced psychopathology, and it is likely that altered amygdala function underlies some of the deleterious effects of psychological stress. To understand the mechanisms underlying the linkage between the response to psychological stressors and maladaptive or psychopathological responses, we have focused on amygdala responsivity in animal models employing species-specific psychological stressors. In the present study, we characterized the effects of a 15-min exposure to a natural predator, the ferret, on rat behavior and the expression of the somatostatin family of genes in the amygdala. We examined the somatostatin family of genes because substantial evidence shows that central somatostatin systems are altered in various neuropsychiatric illnesses. We report that rats respond to acute ferret exposure with a significant increase in fearful and anxious behaviors that is accompanied by robust amygdala activation and an increase in somatostatin receptor 2 (sst2) messenger RNA expression within the amygdala and anterior cingulate cortex. These studies are the first to show stress-induced changes in amygdala sst2 expression and may represent one mechanism by which psychological stress is linked to adaptive and maladaptive behavioral responses.

The development of biosensor with imaging ellipsometry

The concept of biosensor with imaging ellipsometry was proposed about ten years ago. It has become an automatic analysis technique for protein detection with merits of label-free, multi-protein analysis, and real-time analysis for protein interaction process, etc. Its principle, and related technique units, such as micro-array, micro-fluidic and bio-molecule interaction cell, sampling unit and calibration for quantitative detection as well as its applications in biomedicine field are presented here.

Deep Impact: observations from a worldwide Earth-based campaign

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

A novel blocking monoclonal antibody recognizing a distinct epitope of human CD40 molecule

CD40, a member of the tumor necrosis factor receptor superfamily, is an important costimulatory molecule during the immune response. Here, we report a blocking mouse antihuman CD40 monoclonal antibody, mAb 3G3, of which the specificity was verified by flow cytometry and Western blot. It was shown by competition test that 3G3 bound to a different site (epitope) of CD40 from the reported CD40 mAbs, including clone mAb89, 3B2, and 5C11. It was also found that mAb 3G3 could inhibit homotypic aggregation of Daudi cells induced by the agonistic anti-CD40 mAb 5C11. Furthermore, mAb 3G3 effectively inhibited the proliferation of peripheral blood mononuclear cells in mixed lymphocyte reaction assay. Finally, a sensitive and specific soluble CD40 (sCD40) ELISA kit was established by matching mAb 3G3 with 5C11, and it was found that the levels of sCD40 in sera from patients with immune disorders such as hyperthyroidism, chronic nephritis, and rheumatoid arthritis were obviously higher than those from normal individuals. Thus, this blocking anti-CD40 mAb provides a novel tool for the study of CD40.

The neuronal migration defect in mice with Zellweger syndrome (Pex5 knockout) is not caused by the inactivity of peroxisomal beta-oxidation

The purpose of this study was to investigate whether deficient peroxisomal beta-oxidation is causally involved in the neuronal migration defect observed in Pex5 knockout mice. These mice are models for Zellweger syndrome, a peroxisome biogenesis disorder. Neocortical development was evaluated in mice carrying a partial or complete defect of peroxisomal beta-oxidation at the level of the second enzyme of the pathway, namely, the hydratase-dehydrogenase multifunctional/bifunctional enzymes MFP1/L-PBE and MFP2/D-PBE. In contrast to patients with multifunctional protein 2 deficiency who present with neocortical dysgenesis, impairment of neuronal migration was not observed in the single MFP2 or in the double MFP1/MFP2 knockout mice. At birth, the double knockout pups displayed variable growth retardation and about one half of them were severely hypotonic, whereas the single MFP2 knockout animals were all normal in the perinatal period. These results indicate that in the mouse, defective peroxisomal beta-oxidation does not cause neuronal migration defects by itself. This does not exclude that the inactivity of this metabolic pathway contributes to the brain pathology in mice and patients with complete absence of functional peroxisomes.

Cloning and characterization of PIMT, a protein with a methyltransferase domain, which interacts with and enhances nuclear receptor coactivator PRIP function

The nuclear receptor coactivators participate in the transcriptional activation of specific genes by nuclear receptors. In this study, we report the isolation of a nuclear receptor coactivator-interacting protein from a human liver cDNA library by using the coactivator peroxisome proliferator-activated receptor-interacting protein (PRIP) (ASC2/AIB3/RAP250/NRC/TRBP) as bait in a yeast two-hybrid screen. Human PRIP-interacting protein cDNA has an ORF of 2,556 nucleotides, encodes a protein with 852 amino acids, and contains a 9-aa VVDAFCGVG methyltransferase motif I and an invariant GXXGXXI segment found in K-homology motifs of many RNA-binding proteins. The gene encoding this protein, designated PRIP-interacting protein with methyltransferase domain (PIMT), is localized on chromosome 8q11 and spans more than 40 kb. PIMT mRNA is ubiquitously expressed, with a high level of expression in heart, skeletal muscle, kidney, liver, and placenta. Using the immunofluorescence localization method, we found that PIMT and PRIP proteins appear colocalized in the nucleus. PIMT strongly interacts with PRIP under in vitro and in vivo conditions, and the PIMT-binding site on PRIP is in the region encompassing amino acids 773-927. PIMT binds S-adenosyl-l-methionine, the methyl donor for methyltransfer reaction, and it also binds RNA, suggesting that it is a putative RNA methyltransferase. PIMT enhances the transcriptional activity of peroxisome proliferator-activated receptor gamma and retinoid-X-receptor alpha, which is further stimulated by coexpression of PRIP, implying that PIMT is a component of nuclear receptor signal transduction apparatus acting through PRIP. Definitive identification of the specific substrate of PIMT and the role of this RNA-binding protein in transcriptional regulation remain to be determined.

Peroxisome proliferator-activated receptors, coactivators, and downstream targets

Peroxisomes in liver parenchymal cells proliferate in response to structurally diverse nonmutagenic compounds designated as peroxisome proliferators (PP). Sustained induction of peroxisome proliferation and peroxisomal fatty acid beta-oxidation system in rats and mice leads to the development of liver tumors. Two mechanistic issues are important for consideration: elucidation of the upstream events responsible for the tissue and species specific induction of the characteristic pleiotropic responses by PPs; and delineation of the downstream events associated with peroxisome proliferation, and their role in the development of liver tumors in species that are sensitive to the induction of peroxisome proliferation. The induction of peroxisome proliferation is mediated by PP-activated receptor alpha (PPAR alpha), a member of a group of transcription factors that regulate the expression of genes associated with lipid metabolism and adipocyte differentiation. Three isotypes of this family of nuclear receptors, namely PPAR alpha, PPAR gamma, and PPAR delta (also called beta), have been identified as products of separate genes. Although PPAR alpha is responsible for the PP-induced pleiotropic responses, PPAR gamma seems to be involved in adipogenesis and differentiation, but the events associated with PPAR gamma do not directly involve peroxisomes and peroxisome proliferation. PPARs heterodimerize with 9-cis retinoic acid receptor (RXR), and bind to PP response element(s) (PPREs) on the target gene promoter to initiate inducible transcriptional activity. Tissue and species responses to PPs depend on pharmacokinetics, relative abundance of PPAR isotypes, nature of PPRE in the upstream regions of target genes, the extent of competition or cross-talk among nuclear transcription factors for PPAR heterodimerization partner retinoid X receptor and the modulating role of coactivators and corepressors on ligand-dependent transcription of PPARs. Using PPAR as bait in the yeast two-hybrid system, the authors recently cloned mouse steroid receptor coactivator-1 (SRC-1) and PPAR-binding protein (PBP), and identified them as PPAR coactivators. Both SRC-1 and PBP contain LXXLL signature motifs, considered necessary and sufficient for the binding of coactivators to nuclear receptors. A multifaceted approach, which includes the identification of additional coactivators that may be responsible for cell specific transcriptional activation of PPAR-mediated target genes, and generation of genetically modified animals (transgenic and gene disrupted), will be necessary to gain more insight into the upstream and downstream targets responsible for the induction of early and delayed PP-induced pleiotropic responses. In this context, it is important to note that mice deficient in fatty acyl-CoA oxidase, the first and rate-limiting enzyme of the peroxisomal beta-oxidation system, revealed that this enzyme is indispensable for the physiological regulation of PPAR alpha, and the absence of this enzyme leads to sustained transcriptional activation of genes regulated by this receptor.

African Origin of Modern Humans in East Asia: A Tale of 12,000 Y Chromosomes

To test the hypotheses of modern human origin in East Asia, we sampled 12,127 male individuals from 163 populations and typed for three Y chromosome biallelic markers (YAP, M89, and M130). All the individuals carried a mutation at one of the three sites. These three mutations (YAP+, M89T, and M130T) coalesce to another mutation (M168T), which originated in Africa about 35,000 to 89,000 years ago. Therefore, the data do not support even a minimal in situ hominid contribution in the origin of anatomically modern humans in East Asia.

[Adaptive moving averaging based estimation of single event-related potentials]

Event-related potentials (ERP) is pertinent to medical research and clinical diagnosis. Estimation of single event-related potentials (sERP) is the objective of ERP processing. A new technique, adaptive moving averaging based method for estimation of sERP, is presented. After analysis of the properties of background noise by crossing zero, the window length of moving averaging is adaptively set according to the maximum width of the impulse noise for each recorded raw data. The experiments are made with real recorded data and the results demonstrate that the performance of sERP estimation is excellent. So the method proposed is suitable to sERP processing.

Defect in peroxisome proliferator-activated receptor alpha-inducible fatty acid oxidation determines the severity of hepatic steatosis in response to fasting

Fasting causes lipolysis in adipose tissue leading to the release of large quantities of free fatty acids into circulation that reach the liver where they are metabolized to generate ketone bodies to serve as fuels for other tissues. Since fatty acid-metabolizing enzymes in the liver are transcriptionally regulated by peroxisome proliferator-activated receptor alpha (PPARalpha), we investigated the role of PPARalpha in the induction of these enzymes in response to fasting and their relationship to the development of hepatic steatosis in mice deficient in PPARalpha (PPARalpha(-/-)), peroxisomal fatty acyl-CoA oxidase (AOX(-/-)), and in both PPARalpha and AOX (double knock-out (DKO)). Fasting for 48-72 h caused profound impairment of fatty acid oxidation in both PPARalpha(-/-) and DKO mice, and DKO mice revealed a greater degree of hepatic steatosis when compared with PPARalpha(-/-) mice. The absence of PPARalpha in both PPARalpha(-/-) and DKO mice impairs the induction of mitochondrial beta-oxidation in liver following fasting which contributes to hypoketonemia and hepatic steatosis. Pronounced steatosis in DKO mouse livers is due to the added deficiency of peroxisomal beta-oxidation system in these animals due to the absence of AOX. In mice deficient in AOX alone, the sustained hyperactivation of PPARalpha and up-regulation of mitochondrial beta-oxidation and microsomal omega-oxidation systems as well as the regenerative nature of a majority of hepatocytes containing numerous spontaneously proliferated peroxisomes, which appear refractory to store triglycerides, blunt the steatotic response to fasting. Starvation for 72 h caused a decrease in PPARalpha hepatic mRNA levels in wild type mice, with no perceptible compensatory increases in PPARgamma and PPARdelta mRNA levels. PPARgamma and PPARdelta hepatic mRNA levels were lower in fed PPARalpha(-/-) and DKO mice when compared with wild type mice, and fasting caused a slight increase only in PPARgamma levels and a decrease in PPARdelta levels. Fasting did not change the PPAR isoform levels in AOX(-/-) mouse liver. These observations point to the critical importance of PPARalpha in the transcriptional regulatory responses to fasting and in determining the severity of hepatic steatosis.

[Diagnosis and nasal endoscopic surgery of rhinogenic optic function damage]

OBJECTIVE

To explore the diagnosis and the surgical treatment of rhinogenic optic function damage through transnasal endoscopic approach.

METHODS

The clinical characteristics and the results of transnasal endoscopic surgery of 32 cases(32 eyes) with rhinogenic optic function damage were analyzed.

RESULTS

Eleven eyes were cured, 20 eyes were improved, 1 eye failed, No recurrence was found within 6 months to 3 years after operation.

CONCLUSION

The sinus inflammatory disease might injure optic function. Early diagnosis as is important and the endoscopic sinus surgery combined with appropriate medical drug administration are in effective.

Deletion of PBP/PPARBP, the gene for nuclear receptor coactivator peroxisome proliferator-activated receptor-binding protein, results in embryonic lethality

We previously isolated and identified peroxisome proliferator-activated receptor (PPAR)-binding Protein (PBP) as a coactivator for PPARgamma. PBP has recently been identified as a component of the multiprotein complexes such as TRAP, DRIP, and ARC that appear to play an important role in the transcriptional activation by several transcriptional factors including nuclear receptors. To assess the biological significance of PBP, we disrupted the PBP gene (PBP/PPARBP) in mice by homologous recombination. PBP(+/-) mice are healthy, fertile, and do not differ significantly from PBP(+/+) control littermates. PBP null mutation (PBP(-/-)) is embryonically lethal at embryonic day 11.5, suggesting that PBP is an essential gene for mouse embryogenesis. The embryonic lethality is attributed, in part, to defects in the development of placental vasculature similar to those encountered in PPARgamma mutants. Transient transfection assays using fibroblasts isolated from PBP mutant embryos revealed a decreased capacity for ligand-dependent transcriptional activation of PPARgamma as compared with fibroblasts derived form the wild type embryos. These observations suggest that there is no functional redundancy between PBP and other coactivators such as steroid receptor coactivator-1 and that PBP plays a critical role in the signaling of PPARgamma and other nuclear receptors.

Isolation and characterization of peroxisome proliferator-activated receptor (PPAR) interacting protein (PRIP) as a coactivator for PPAR

We previously isolated and identified steroid receptor coactivator-1 (SRC-1) and peroxisome proliferator-activated receptor (PPAR)-binding protein (PBP/PPARBP) as coactivators for PPAR, using the ligand-binding domain of PPARgamma as bait in a yeast two-hybrid screening. As part of our continuing effort to identify cofactors that influence the transcriptional activity of PPARs, we now report the isolation of a novel coactivator from mouse, designated PRIP (peroxisome proliferator-activated receptor interacting protein), a nuclear protein with 2068 amino acids and encoded by 13 exons. Northern analysis showed that PRIP mRNA is ubiquitously expressed in many tissues of adult mice. PRIP contains two LXXLL signature motifs. The amino-terminal LXXLL motif (amino acid position 892 to 896) of PRIP was found to be necessary for nuclear receptor interaction, but the second LXXLL motif (amino acid position 1496 to 1500) appeared unable to bind PPARgamma. Deletion of the last 12 amino acids from the carboxyl terminus of PPARgamma resulted in the abolition of the interaction between PRIP and PPARgamma. PRIP also binds to PPARalpha, RARalpha, RXRalpha, ER, and TRbeta1, and this binding is increased in the presence of specific ligands. PRIP acts as a strong coactivator for PPARgamma in the yeast and also potentiates the transcriptional activities of PPARgamma and RXRalpha in mammalian cells. A truncated form of PRIP (amino acids 786-1132) acts as a dominant-negative repressor, suggesting that PRIP is a genuine coactivator.

Tumor necrosis factor-alpha-induced insulin resistance in adipocytes

Recent studies examining the link between insulin resistance and the development of obesity and noninsulin-dependent diabetes mellitus are consistent with the involvement of tumor necrosis factor-alpha (TNF-alpha) as a central mediator. In insulin resistant obese mouse models, neutralization of TNF-alpha in circulation has been demonstrated to restore insulin-mediated glucose uptake. Adipose tissue has been shown to be a site for synthesis of TNF-alpha, with the degree of adiposity directly correlated with the level of synthesis. Studies conducted on obese human patients have demonstrated a correlation between levels of TNF-alpha, the extent of obesity, as well as the level of hyperinsulinemia observed. Mechanistic studies in cell culture have suggested that TNF-alpha functions to render cells insulin resistant through regulation of the synthesis of the insulin responsive glucose transporter as well as through interference with insulin signaling. This review will address these issues and additionally introduce the reader to the molecular aspects of TNF-alpha, its receptors as well as TNF-alpha-initiated signaling cascades, that are necessary to understand the function of this cytokine in the regulation of adipose tissue metabolism.

The influence of mRNA stability on glucose transporter (GLUT1) gene expression

One mechanism for modification of glucose transport activity occurs through regulation of the cellular content of transporter protein by alteration of transcript stability. Regulated mRNA decay has been shown to play an important role in control of posttranscriptional gene expression. Implicated, as a pivotal element in this regulation is the 3'-untranslated region (UTR) of the message. Recent work from several labs has focused on sequence motifs within the 3'-UTR of glucose transporter (GLUT1) mRNA that serve as destabilizing or stabilizing elements and recognition of these elements by specific proteins. In this review, we address several critical studies each of which has identified elements in the GLUT1 3'-UTR that are involved in the control of transcript stability and demonstrated that these sequence motifs are recognized by specific binding proteins.

Amplification and overexpression of peroxisome proliferator-activated receptor binding protein (PBP/PPARBP) gene in breast cancer

Peroxisome proliferator-activated receptor binding protein (PBP), a nuclear receptor coactivator, interacts with estrogen receptor alpha (ERalpha) in the absence of estrogen. This interaction was enhanced in the presence of estrogen but was reduced in the presence of antiestrogen, tamoxifen. Transfection of PBP in CV-1 cells resulted in enhancement of estrogen-dependent transcription, indicating that PBP serves as a coactivator in ER signaling. To examine whether overexpression of PBP plays a role in breast cancer because of its coactivator function in ER signaling, we determined the levels of PBP expression in breast tumors. High levels of PBP expression were detected in approximately 50% of primary breast cancers and breast cancer cell lines by ribonuclease protection analysis, in situ hybridization, and immunoperoxidase staining. Fluorescence in situ hybridization of human chromosomes revealed that the PBP gene is located on chromosome 17q12, a region that is amplified in some breast cancers. We found PBP gene amplification in approximately 24% (6/25) of breast tumors and approximately 30% (2/6) of breast cancer cell lines, implying that PBP gene overexpression can occur independent of gene amplification. This gene comprises 17 exons that, together, span >37 kilobases. The 5'-flanking region of 2.5 kilobase pairs inserted into a luciferase reporter vector revealed that the promoter activity in CV-1 cells increased by deletion of nucleotides from -2,500 to -273. The -273 to +1 region, which exhibited high promoter activity, contains a typical CCAT box and multiple cis-elements such as C/EBPbeta, YY1, c-Ets-1, AP1, AP2, and NFkappaB binding sites. These observations, in particular PBP gene amplification, suggest that PBP, by its ability to function as ERalpha coactivator, might play a role in mammary epithelial differentiation and in breast carcinogenesis.

Thermometric analysis of intra-cavitary hyperthermia for esophageal cancer

Thermometric analysis was carried out in 51 patients with esophageal cancer treated with intra-cavitary hyperthermia combined with radio chemotherapy, to test whether temperature index (T20, T50) and T90) could be used as an indicator for tumour control. Hyperthermia was administered by intra-cavitary microwave applicator. The T20, T50 and T90 were deducted from the temperature sensors T0 and T3 situated at the center of the tumour surface and 3cm from it. Eighteen patients with local control > or =36 months were named long term control patients (LC), 24 patients with local recurrence within 24 months (LR) (there were no events occurring between 24 and 36 months) and nine patients died of metastasis without local recurrence (DM). The overall survival rates were 80.4 +/- 5.6% at 1 year, 38.3 +/- 6.9% at 3 years and 31 +/- 6.7% at 5 years, respectively. Chi-square test showed no influence of the number of hyperthermia sessions on the local control (p > 0.25). The 5-year local control rate was 18.8% for the patients with T90 < 43 degrees C and 45% for those with T90 > or = 43 degrees C (p < 0.01). The average T90 was 43.76 +/- 0.74 degrees C for the LC patients and 43.17 +/- 0.57 degrees C for those LR (p = 0.024). The mean T90 was higher than 43 degrees C in 94.4% of LC, whereas in 58.8% of LR. The study suggested that T90 was a good parameter for thermal dose in the intracavitary hyperthermia for the treatment of esophageal cancer.

Peroxisomal and mitochondrial fatty acid beta-oxidation in mice nullizygous for both peroxisome proliferator-activated receptor alpha and peroxisomal fatty acyl-CoA oxidase. Genotype correlation with fatty liver phenotype

Fatty acid beta-oxidation occurs in both mitochondria and peroxisomes. Long chain fatty acids are also metabolized by the cytochrome P450 CYP4A omega-oxidation enzymes to toxic dicarboxylic acids (DCAs) that serve as substrates for peroxisomal beta-oxidation. Synthetic peroxisome proliferators interact with peroxisome proliferator activated receptor alpha (PPARalpha) to transcriptionally activate genes that participate in peroxisomal, microsomal, and mitochondrial fatty acid oxidation. Mice lacking PPARalpha (PPARalpha-/-) fail to respond to the inductive effects of peroxisome proliferators, whereas those lacking fatty acyl-CoA oxidase (AOX-/-), the first enzyme of the peroxisomal beta-oxidation system, exhibit extensive microvesicular steatohepatitis, leading to hepatocellular regeneration and massive peroxisome proliferation, implying sustained activation of PPARalpha by natural ligands. We now report that mice nullizygous for both PPARalpha and AOX (PPARalpha-/- AOX-/-) failed to exhibit spontaneous peroxisome proliferation and induction of PPARalpha-regulated genes by biological ligands unmetabolized in the absence of AOX. In AOX-/- mice, the hyperactivity of PPARalpha enhances the severity of steatosis by inducing CYP4A family proteins that generate DCAs and since they are not metabolized in the absence of peroxisomal beta-oxidation, they damage mitochondria leading to steatosis. Blunting of microvesicular steatosis, which is restricted to few liver cells in periportal regions in PPARalpha-/- AOX-/- mice, suggests a role for PPARalpha-induced genes, especially members of CYP4A family, in determining the severity of steatosis in livers with defective peroxisomal beta-oxidation. In age-matched PPARalpha-/- mice, a decrease in constitutive mitochondrial beta-oxidation with intact constitutive peroxisomal beta-oxidation system contributes to large droplet fatty change that is restricted to centrilobular hepatocytes. These data define a critical role for both PPARalpha and AOX in hepatic lipid metabolism and in the pathogenesis of specific fatty liver phenotype.

Absence of spontaneous peroxisome proliferation in enoyl-CoA Hydratase/L-3-hydroxyacyl-CoA dehydrogenase-deficient mouse liver. Further support for the role of fatty acyl CoA oxidase in PPARalpha ligand metabolism

Peroxisomes contain a classical L-hydroxy-specific peroxisome proliferator-inducible beta-oxidation system and also a second noninducible D-hydroxy-specific beta-oxidation system. We previously generated mice lacking fatty acyl-CoA oxidase (AOX), the first enzyme of the L-hydroxy-specific classical beta-oxidation system; these AOX-/- mice exhibited sustained activation of peroxisome proliferator-activated receptor alpha (PPARalpha), resulting in profound spontaneous peroxisome proliferation in liver cells. These observations implied that AOX is responsible for the metabolic degradation of PPARalpha ligands. In this study, the function of enoyl-CoA hydratase/L-3-hydroxyacyl-CoA dehydrogenase (L-PBE), the second enzyme of this peroxisomal beta-oxidation system, was investigated by disrupting its gene. Mutant mice (L-PBE-/-) were viable and fertile and exhibited no detectable gross phenotypic defects. L-PBE-/- mice showed no hepatic steatosis and manifested no spontaneous peroxisome proliferation, unlike that encountered in livers of mice deficient in AOX. These results indicate that disruption of classical peroxisomal fatty acid beta-oxidation system distal to AOX step does not interfere with the inactivation of endogenous ligands of PPARalpha, further confirming that the AOX gene is indispensable for the physiological regulation of this receptor. The absence of appreciable changes in lipid metabolism also indicates that enoyl-CoAs, generated in the classical system in L-PBE-/- mice are diverted to D-hydroxy-specific system for metabolism by D-PBE. When challenged with a peroxisome proliferator, L-PBE-/- mice showed increases in the levels of hepatic mRNAs and proteins that are regulated by PPARalpha except for appreciable blunting of peroxisome proliferative response as compared with that observed in hepatocytes of wild type mice similarly treated. This blunting of peroxisome proliferative response is attributed to the absence of L-PBE protein in L-PBE-/- mouse liver, because all other proteins are induced essentially to the same extent in both wild type and L-PBE-/- mice.

Sublimation from icy jets as a probe of the interstellar volatile content of comets

Comets are some of the most primitive bodies left over from the Solar System's early history. They may preserve both interstellar material and material from the proto-solar nebula, and so studies of their volatile components can provide clues about the evolution of gases and ices, as a collapsing molecular cloud transforms into a mature planetary system. Previous observations of emission from rotational transitions in molecules have averaged over large areas of the inner coma, and therefore include both molecules that sublimed from the nucleus and those that result from subsequent chemical processes in the coma Here we present high-resolution observations of emission from the molecules HNC, DCN and HDO associated with comet Hale-Bopp. Our data reveal arc-like structures-icy jets-offset from (but close to) the nucleus. The measured abundance ratios on 1-3" scales are substantially different from those on larger scales, and cannot be accounted for by models of chemical processes in the coma; they are, however, similar to the values observed in the cores of dense interstellar clouds and young stellar objects. We therefore propose that sublimation from millimetre-sized icy grains ejected from the nucleus provides access to relatively unaltered volatiles. The D/H ratios inferred from our data suggest that, by mass, Hale-Bopp (and by inference the outer regions of the early solar nebula) consists of > or =15-40% of largely unprocessed interstellar material.

[Biologic behavior and prognosis of patients with gastric cancer in young persons]

OBJECTIVE

To explore the relationship between the biological behavior and prognostic factors in treating gastric cancer of young persons by various surgical methods.

METHODS

89 young patients with gastric cancer aged 35 years or less were analyzed.

RESULTS

The resectable rate was 73.0% (65/89), radical resectable rate 48.3% (43/89), and palliative resectable rate 24.7% (22/89). The 5-year survival rate was 24.7% (22/89) and 48.8% (21/43) for the radical group. Biological characteristics included infiltrated, diffused growth, lymph node metastasis, female predominance.

CONCLUSIONS

The biological behavior of gastric cancer in young persons is poor. Early management gastric cancer and radical operation combined with complex treatment are essential.

Mouse steroid receptor coactivator-1 is not essential for peroxisome proliferator-activated receptor alpha-regulated gene expression

Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors, and it is assumed that the biological effects of these receptors depend on interactions with recently identified coactivators, including steroid receptor coactivator-1 (SRC-1). We assessed the in vivo function of SRC-1 on the PPARalpha-regulated gene expression in liver by generating mice in which the SRC-1 gene was inactivated by gene targeting. The homozygous (SRC-1(-/-)) mice were viable and fertile and exhibited no detectable gross phenotypic defects. When challenged with a PPARalpha ligand, such as ciprofibrate or Wy-14,643, the SRC-1(-/-) mice displayed typical pleiotropic responses, including hepatomegaly, peroxisome proliferation in hepatocytes, and increased mRNA and protein levels of genes that are regulated by PPARalpha. These alterations were indistinguishable from those exhibited by SRC-1(+/+) wild-type mice fed either ciprofibrate- or Wy-14, 643-containing diets. These results indicate that SRC-1 is not essential for PPARalpha-mediated transcriptional activation in vivo and suggest redundancy in nuclear receptor coactivators.

[Primary experience in inframammary crease reconstruction]

OBJECTIVE

To improve the result of augmentation mammaplasty.

METHODS

The authors selected 15 patients whose primary breast volume was less than 70 ml. During augmentation mammaplasty on these patients, the inframammary creases were reconstructed by lifting and fixation under the pectorales major. The paper elaborated on the principle, design and method of the operation.

RESULTS

Postoperative follow-up for 6 to 12 months showed good results.

CONCLUSION

This method is simple, of rational design and leaving no scar on the skin.

Differential expression of the peroxisome proliferator-activated receptor gamma (PPARgamma) and its coactivators steroid receptor coactivator-1 and PPAR-binding protein PBP in the brown fat, urinary bladder, colon, and breast of the mouse

Peroxisome proliferator-activated receptors (PPARs) regulate genes involved in lipid metabolism and adipocyte differentiation. Steroid receptor coactivator-1 (SRC-1) and PPAR-binding protein (PBP) interact with PPARgamma and act as coactivators to enhance ligand-dependent transcription. We report here that PPARgamma, SRC-1, and PBP are differentially expressed in the brown fat, transitional epithelium of the urinary bladder, colonic mucosa, and mammary epithelium of the adult mouse. PPARgamma and PBP are expressed in the transitional epithelium of urinary bladder and in brown adipose tissue, but not SRC-1. In the colonic mucosa, PPARgamma expression occurs throughout the villi, whereas the expression of both SRC-1 and PBP is confined mostly to the crypts. The expression of both SRC-1 and PBP is prominent in the breast epithelium of nonpregnant, pregnant, and lactating mice, whereas PPARgamma expression appeared prominent during lactation. During early embryonic development, PPARgamma, SRC-1, and PBP are differentially expressed, with only limited cell types displaying overlapping expression. PPARgamma and PBP expression overlapped in the brown fat and urogenital sinus at stage E15.5 of embryogenesis, whereas SRC-1 expression occurred mostly in neuroepithelium and cartilage between stages E9.5 and E13.5 of embryogenesis.

Lysophosphatidic acid stimulates phospholipase D activity and cell proliferation in PC-3 human prostate cancer cells

Phospholipase D (PLD) is activated in mammalian cells in response to a variety of growth factors and may play a role in cell proliferation. Lysophosphatidic acid (LPA) is a bioactive metabolite potentially generated as a result of PLD activation. Two human prostate cancer cell lines, PC-3 and LNCaP, express membrane PLD activity. The effects of LPA on PLD activity and proliferation were examined in PC-3 cells, which express hPLD1a/1b. Phorbol 12-myristate 13-acetate (PMA) induced a prolonged activation of PLD, as detected in both intact cells and membranes. LPA induced a transient activation of PLD that was maximal by 10 minutes. The EC50 for LPA-induced PLD activation was approximately 1 microM. Pertussis toxin did not inhibit activation of PLD by LPA or PMA. Ro-31-8220 and bisindolylmaleimide I, inhibitors of protein kinase C, blocked activation by PLD by both PMA and LPA. PMA-induced activation of PLD did not appear to require translocation of PLDs from cytosol to membrane. LPA stimulated proliferation of PC-3 cells with an EC50 of approximately 0.2 microM; this response was not inhibited by pertussis toxin. Perillyl alcohol, an anti-cancer drug, reversibly inhibited proliferation in response to either serum or LPA but did not inhibit activation of PLD by PMA or LPA. These data establish that LPA activates PLD and stimulates proliferation via Gi-independent pathways in a human prostate cancer cell line.

Isolation and characterization of PBP, a protein that interacts with peroxisome proliferator-activated receptor

In an attempt to identify cofactors that could possibly influence the transcriptional activity of peroxisome proliferator-activated receptors (PPARs), we used a yeast two-hybrid system with Gal4-PPARgamma as bait to screen a mouse liver cDNA library and have identified steroid receptor coactivator-1 (SRC-1) as a PPAR transcriptional coactivator. We now report the isolation of a cDNA encoding a 165-kDa PPARgamma-binding protein, designated PBP which also serves as a coactivator. PBP also binds to PPARalpha, RARalpha, RXR, and TRbeta1, and this binding is increased in the presence of specific ligands. Deletion of the last 12 amino acids from the carboxyl terminus of PPARgamma results in the abolition of interaction between PBP and PPARgamma. PBP modestly increased the transcriptional activity of PPARgamma, and a truncated form of PBP (amino acids 487-735) acted as a dominant-negative repressor, suggesting that PBP is a genuine coactivator for PPAR. In addition, PBP contains two LXXLL signature motifs considered necessary and sufficient for the binding of several coactivators to nuclear receptors. In situ hybridization and Northern analysis showed that PBP is expressed in many tissues of adult mice, including the germinal epithelium of testis, where it appeared most abundant, and during ontogeny, suggesting a possible role for this cofactor in cellular proliferation and differentiation.

Effects of protein kinase C activators on phorbol ester-sensitive and -resistant EL4 thymoma cells

Phorbol ester-sensitive EL4 murine thymoma cells respond to phorbol 12-myristate 13-acetate with activation of ERK mitogen-activated protein kinases, synthesis of interleukin-2, and death, whereas phorbol ester-resistant variants of this cell line do not exhibit these responses. Additional aspects of the resistant phenotype were examined, using a newly-established resistant cell line. Phorbol ester induced morphological changes, ERK activation, calcium-dependent activation of the c-Jun N-terminal kinase (JNK), interleukin-2 synthesis, and growth inhibition in sensitive but not resistant cells. A series of protein kinase C activators caused membrane translocation of protein kinase C's (PKCs) alpha, eta, and theta in both cell lines. While PKC eta was expressed at higher levels in sensitive than in resistant cells, overexpression of PKC eta did not restore phorbol ester-induced ERK activation to resistant cells. In sensitive cells, PKC activators had similar effects on cell viability and ERK activation, but differed in their abilities to induce JNK activation and interleukin-2 synthesis. PD 098059, an inhibitor of the mitogen activated protein (MAP)/ERK kinase kinase MEK, partially inhibited ERK activation and completely blocked phorbol ester-induced cell death in sensitive cells. Thus MEK and/or ERK activation, but not JNK activation or interleukin-2 synthesis, appears to be required for phorbol ester-induced toxicity. Alterations in phorbol ester response pathways, rather than altered expression of PKC isoforms, appear to confer phorbol ester resistance to EL4 cells.

[A study on the action of tang niao kang decoction]

Experiments have verified that Tang Niao Karg (a preparation from Chinese medicinal herbs) taken orally does not decrease the blood sugar of empty stomach in mice, but markedly helps lower high levels of blood sugar and lipid induced by epinephrine and glucose in mice. For rat models of diabetes induced by 4-o-pyrincidine Tang Niao Kang can significantly lower the content of blood sugar, raise the insulin level of blood serum, and enhance the tolerance to sugar.

Phospholipase D activity in PC12 cells. Effects of overexpression of alpha2A-adrenergic receptors

PC12 neuronal cells express a membrane phospholipase D (PLD) activity that is detected at similar levels in undifferentiated or differentiated cells. The regulation of this activity by agonists was explored. Membrane phospholipase D activity was increased by treatment of cells with the phorbol ester phorbol 12-myristate 13-acetate (PMA) or with nerve growth factor. The ability of PMA to activate PLD was confirmed in intact PC12 cells. Basal activity of PLD in membranes was reduced in RG20, a PC12 cell line overexpressing the human alpha2A-adrenergic receptor. PMA did not increase PLD activity in RG20 cells, as assessed both in membrane preparations and in intact cells. Cyclic AMP levels did not regulate phospholipase D activity in either cell type. However, incubation of RG20 cells with the alpha2-adrenergic antagonist rauwolscine or with pertussis toxin increased membrane PLD activity and restored activation of PLD by PMA. These data suggest that the effects of the overexpressed alpha2A-adrenergic receptor on PLD activity are mediated by precoupling of the receptor to the heterotrimeric GTP-binding protein, Gi, but are independent of adenylate cyclase regulation. The results of this study suggest that membrane phospholipase D activity can be negatively regulated via Gi in PC12 cells.

Characterization of a sphingomyelinase activity in Saccharomyces cerevisiae

Sphingomyelinases (SMase), which hydrolyze sphingolipids to yield ceramide, participate in signal transduction pathways in mammalian cells. Although yeast express many homologs of mammalian signaling proteins, SMase activity had not been previously demonstrated in yeast. In this study, we used an in vitro assay to characterize yeast SMase activity. Activity was detected in yeast membranes at both acid and neutral pH. The enzyme exhibited a requirement for magnesium or manganese, and was sensitive to detergents. The pI of the enzyme was approximately 5.9. SMase was separable from phospholipase D (PLD) activity, and was expressed at normal levels in yeast lacking expression of PLD1. While sphingosine and phytosphingosine inhibited growth, other sphingolipid metabolites had no effect on yeast growth. Intact yeast generate ceramide from exogenous sphingomyelin. These studies demonstrate that yeast express a membrane-localized neutral SMase activity.

Effects of phorbol ester on phospholipase D and mitogen-activated protein kinase activities in T-lymphocyte cell lines

The effects of phorbol 12-myristate 13-acetate (PMA) on the activities of phospholipase D (PLD3), mitogen-activated protein kinase (ERK), and c-Jun N-terminal kinase (JNK) were studied in Jurkat, a human T cell line, and EL4, a murine T-cell line. PMA treatment rapidly activated PLD in Jurkat, as detected either in intact or broken cells. In contrast, PMA did not stimulate PLD activity in EL4 cells. PLD activity was not detected in membranes prepared from EL4 cells. Jurkat, but not EL4, expresses a 120-kDa protein recognized by an anti-PLD antibody. In both Jurkat and EL4 cells, PMA caused activation of ERKs. Incubation of EL4 cells with bacterial PLD increased phosphatidic acid levels, but did not activate ERK. In both EL4 and Jurkat cells, co-stimulation with PMA and ionomycin stimulated JNK activity. These results show that activation of PLD is not required for activation of ERKs or JNKs by PMA in T-cell lines. Thus, while PLD activity is expressed in some T-cell lines, the role of this enzyme and its products in T-cell activation remain to be elucidated.

Bile but not chyle lipoprotein is an important source of arachidonic acid for the rat small intestine

Arachidonic acid (AA) functions as a structural component, eicosanoid precursor and surface material for chylomicron production in the gastrointestinal tract. The origin of this AA is poorly characterized. [3H]AA labelled chylomicrons and [14C]AA albumin-FFA were injected intravenously into biliary diverted rats and controls. Radioactivity in tissue lipids was measured after different time intervals. Output of 3H and 14C in bile was 8% of the injected dose during 24 h. Radioactivity of the upper small intestine but not of colon and stomach increased with time. Bile drain reduced the recovered amounts of radioactivity in upper small intestine by 75% after 24 h. In stomach and colon 3H/g tissue was 16-20 fold lower than in liver after 24 h. Recovery of 3H in liver was higher than of 14C. In liver 3H/g tissue was 15-40 fold higher than in stomach and colon after 10-60 min. Equilibration between AA pools of liver and other organs was not complete after 96 h. Biliary phospholipid is an important source of AA for the small intestine.