The instability of the membrane skeleton in thalassemic red blood cells

The thalassemias are a heterogeneous group of disorders characterized by accumulation either of unmatched alpha or beta globin chains. These in turn cause the intramedullary and peripheral hemolysis that leads to varying anemia. A partial explanation for the hemolysis came our of our studies on material properties that showed that beta-thalassemia (beta-thal) intermedia ghosts were very rigid but unstable. A clue to this instability came from the observation that the spectrin/band 3 ratio was low in red blood cells (RBCs) of splenectomized beta-thal intermedia patients. The possible explanations for the apparent decrease in spectrin content included deficient or defective spectrin synthesis in thalassemic erythroid precursors or globin chain-induced membrane changes that lead to spectrin dissociation from the membrane during ghost preparation. To explore the latter alternative, samples from different thalassemic variants were obtained, ie, beta-thal intermedia, HbE/beta-thal, HbH (alpha-thal-1/alpha-thal-2), HbH/Constant Spring (CS), and homozygous HbCS/CS. We searched for the presence of spectrin in the first lysate of the standard ghost preparation. Normal individuals and patients with autoimmune hemolytic anemia, sickle cell anemia, and anemia due to chemotherapy served as controls. Using gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, no spectrin was detected in identical aliquots of the supernatants of normals and these control samples. Varying amounts of spectrin were detected in the first lysate supernatants of almost all thalassemic patients. The identification of spectrin was confirmed by Western blotting using an affinity-purified, monospecific, rabbit polyclonal antispectrin antibody. Relative amounts of spectrin detected were as follows in decreasing order: splenectomized beta-thal intermedia including HbE/beta-thal; HbCS/CS; nonsplenectomized beta-thal intermedia, HbH/CS; and, lastly, HbH. These findings were generally confirmed when we used an enzyme-linked immunosorbent assay technique to measure spectrin in the first lysate. Subsequent analyses showed that small amounts of actin and band 4.1 also appeared in lysates of thalassemic RBCs. Therefore, the three major membrane skeletal proteins are, to a varying degree, unstably attached in severe thalassemia. From these studies we could postulate that membrane association of abnormal or partially oxidized alpha-globin chains has a more deleterious effect on the membrane skeleton than do beta-globin chains.

Rat neutrophil defensins. Precursor structures and expression during neutrophilic myelopoiesis

Defensins constitute a family of 3- to 4-kDa antimicrobial peptides that are stored in the cytoplasmic granules of neutrophils, some macrophages, and intestinal Paneth cells. We have assessed defensin gene expression during myeloid differentiation by first characterizing cDNAs for each of the four known rat neutrophil defensins (RatNP 1-4). The cDNA sequences revealed that the peptides are synthesized as 87-94 amino acid precursors, each containing signal, pro-, and mature peptide segments. RatNP-3 and -4 mRNAs, but not those for RatNP-1 and -2 or other myeloid defensins, contained unique polypurine tracts located close to the termination codon in the 3' untranslated region. By using cDNA probes and/or riboprobes, we evaluated defensin transcript levels in a variety of tissues and in the full spectrum of neutrophil precursors. By in situ hybridization, defensin mRNAs were localized to neutrophil precursors in the bone marrow, with the highest mRNA levels occurring in promyelocytes and somewhat lower signals occurring in myeloblasts and myelocytes. Defensin mRNAs were not detectable in bands or mature neutrophils, nor at significant levels in tissues other than bone marrow. The accumulation of defensin protein in bone marrow cells was assessed by immunohistochemical staining with anti-RatNP-1 Ab. RatNP 1-4 mRNAs and protein levels were then correlated for each stage of neutrophilic differentiation to reveal the maturational profile of myeloid defensin gene expression in the rat.

Rat neutrophil defensins. Precursor structures and expression during neutrophilic myelopoiesis

Defensins constitute a family of 3- to 4-kDa antimicrobial peptides that are stored in the cytoplasmic granules of neutrophils, some macrophages, and intestinal Paneth cells. We have assessed defensin gene expression during myeloid differentiation by first characterizing cDNAs for each of the four known rat neutrophil defensins (RatNP 1-4). The cDNA sequences revealed that the peptides are synthesized as 87-94 amino acid precursors, each containing signal, pro-, and mature peptide segments. RatNP-3 and -4 mRNAs, but not those for RatNP-1 and -2 or other myeloid defensins, contained unique polypurine tracts located close to the termination codon in the 3' untranslated region. By using cDNA probes and/or riboprobes, we evaluated defensin transcript levels in a variety of tissues and in the full spectrum of neutrophil precursors. By in situ hybridization, defensin mRNAs were localized to neutrophil precursors in the bone marrow, with the highest mRNA levels occurring in promyelocytes and somewhat lower signals occurring in myeloblasts and myelocytes. Defensin mRNAs were not detectable in bands or mature neutrophils, nor at significant levels in tissues other than bone marrow. The accumulation of defensin protein in bone marrow cells was assessed by immunohistochemical staining with anti-RatNP-1 Ab. RatNP 1-4 mRNAs and protein levels were then correlated for each stage of neutrophilic differentiation to reveal the maturational profile of myeloid defensin gene expression in the rat.

Induction of p53 in mouse cells decreases mutagenesis by UV radiation

The tumor suppressor protein, p53, is proposed to have a critical role in maintaining the integrity of the genetic material. It has been established that p53 induces a cell cycle block in the G1 phase upon cellular DNA damage. Recent evidence also indicates the involvement of p53 directly and indirectly in nucleotide excision repair (NER). We have examined the role of p53 with respect to UV-induced mutagenesis. By gene transfer, we established a mouse fibroblast cell line overexpressing the val135 temperature-sensitive p53 allele. In this line, p53 activity can be modulated through temperature shift, as confirmed by Western blot and by cell cycle analysis. This cell line was also constructed to contain a recoverable lambda phage shuttle vector carrying the supF mutation reporter gene. Induction of p53 was found to enhance the clonogenic survival of the cells following UV-irradiation compared to the p53-deficient parental mouse cell line. The transfectant line also displayed a 4-fold reduction in the frequency of UV-induced mutations as measured in the chromosomally integrated supF reporter gene. Our results are consistent with a p53-induced cell cycle block at G1 allowing cells to repair chromosomal damage before DNA replication. However, our data may also reflect a more direct role of p53 in the repair of UV-induced lesions as suggested by studies showing that p53 can interact directly with repair factors.

p53 inactivation by HPV16 E6 results in increased mutagenesis in human cells

To study the pathways associated with genomic instability in cancer, we examined UV-induced and spontaneous mutagenesis in clonal cell lines expressing human papillomavirus (HPV) proteins, either high-risk (HPV16) E6 or E7 or low-risk (HPV11) E6, in comparison to the parental RKO cells, a colon carcinoma cell line expressing only normal p53. High-risk E6 and E7 bind and functionally inactivate tumor suppressor proteins p53 and Rb, respectively, and both disrupt the G1 arrest in response to DNA damage. Low-risk HPV E6 proteins bind p53 with much lower affinity than high-risk E6 and fail to mediate p53 degradation or to disrupt the G1 checkpoint. We found that cells expressing HPV16 E6 had reduced survival and increased mutagenesis at the hprt locus when treated with low doses of UV. However, this analysis was complicated by the unexpected observation of a very high background of spontaneous mutagenesis in the unirradiated cells expressing the HPV16 E6 gene. Fluctuation analysis revealed a 5-fold elevated mutation rate in the cells expressing HPV16 E6. HPV11 E6 conferred a 2-fold elevation in the mutation rate, but HPV16 E7 had no effect. The increased spontaneous mutagenesis, therefore, appeared to be mediated by p53 inactivation and to be independent of Rb (which acts downstream of p53 in the G1 arrest pathway following DNA damage). Taken together, these findings suggest that the effect of p53 inactivation on spontaneous mutagenesis is manifested at the level of DNA repair, recombination, or coupling of transcription with one of these processes instead of by an alteration in G1 arrest.

[An experimental study of the expression and localization of tumor necrosis factor mRNA in liver of rats with severe burn]

In situ hybridization was used to study the expression and localization of tumor necrosis factor (TNF) mRNA in liver of rats after burn. The results showed that the Kupffer cells expressed TNF mRNA in normal rats. After burn, the number of positive expression cells increased quickly, the expression reached max-mum at 6h postburn, and there were no significantly different with normal at 24h postburn. The dynamic changes of number of TNF mRNA producing cells was similar to that of the portal plasma endotoxin level. Kupffer cells located in sinusoid surrounding portal vein expressed TNF mRNA especially at 6h-12h postburn. Also the sinusoid endothlial cells and infiltrative inflammation cells surrounding portal vein were the TNF mRNA-producing cells, this changes appeared significantly at 12-24h postburn. The results suggested that the endotoxin originated from gut may be the principal stimulator for expression of TNF mRNA. The expression of endothlial cells and neutrophils suggested that these cells had been activated. So the endothlium, neutrophils and Kupffer cell play an important role in the pathogenesis of the endotoxin-induced live injury.

Fenfluramine's appetite suppression and serotonin neurotoxicity are separable

To determine whether fenfluramine's anorectic and neurotoxic effects could be dissociated, rats were treated with fenfluramine or the serotonin transporter blocker fluoxetine, alone or in combination. Fenfluramine alone produced anorexia, weight loss and lasting depletions of brain serotonin axon markers. Fluoxetine prevented fenfluramine-induced long-term serotonergic deficits, yet did not diminish fenfluramine's acute anorectic effects. These findings indicate that fenfluramine's anorectic and neurotoxic actions are distinct and separable.

Tumor necrosis factor-induced apoptosis is mediated by a CrmA-sensitive cell death pathway

We report here that the activation of the interleukin 1 beta (IL-1 beta)-converting enzyme (ICE) family is likely to be one of the crucial events of tumor necrosis factor (TNF) cytotoxicity. The cowpox virus CrmA protein, a member of the serpin superfamily, inhibits the enzymatic activity of ICE and ICE-mediated apoptosis. HeLa cells overexpressing crmA are resistant to apoptosis induced by Ice but not by Ich-1, another member of the Ice/ced-3 family of genes. We found that the CrmA-expressing HeLa cells are resistant to TNF-alpha/cycloheximide (CHX)-induced apoptosis. Induction of apoptosis in HeLa cells by TNF-alpha/CHX is associated with secretion of mature IL-1 beta, suggesting that an IL-1 beta-processing enzyme, most likely ICE itself, is activated by TNF-alpha/CHX stimulation. These results suggest that one or more members of the ICE family sensitive to CrmA inhibition are activated and play a critical role in apoptosis induced by TNF.

Effects of drinking pattern on the peak/trough blood concentrations in drinking water studies

The effects of changes in drinking patterns on the expected peak/trough blood concentrations of test compounds were examined during rodent dosed drinking water studies. They were based on the assumption that the kinetics of the test compound is linear and time-invariant. Results indicate that drinking patterns have minor effects on the expected peak/trough concentrations and the time to reach these concentrations. If a 12-hr light/dark cycle starting at 7.00 is used for all the drinking patterns studied, the peak and trough concentrations will occur in the early morning and late afternoon, respectively. A comparison of the predicted versus experimentally determined pentachlorophenol (PCP) plasma concentrations in a 1-wk rat drinking water study revealed that using a circadian rhythm drinking pattern in the model generated the most satisfactory prediction. Predictions based on a square wave drinking pattern with 90% drinking activities in the night phase were also excellent. Triangular or sinusoidal drinking patterns were least accurate in predictions.

Characterization of polymorphism within the H2-M MHC class II loci

The products of the class II-like H2-M genes of the major histocompatibility complex are required for class II antigen processing. We sequenced H2-Ma and Mb from several mouse strains to determine whether these genes are polymorphic like the classical H2-A and E genes, or are oligomorphic, like H2-O. Both Mb loci appear to be transcribed and are distinct from each other. Mb1 and Mb2 differ by about 11% at the nucleotide level and are most dissimilar in their second exons (corresponding to the beta 1 domain). Relative to the published Mb1d haplotype sequence, the products of the b, g7, f, and k2 alleles of Mb1 from Mus musculus domesticus and the separate mouse species Mus spretus differ by only one to four amino acids. The majority of the changes occurred in the second exon of Mb1, in contrast to HLA-DMB, the human orthologue. Little polymorphism was seen for Mb2, and Ma was invariant in all strains tested. The similarity of the g7 allele to those from other haplotypes makes it unlikely that the M class II genes play a role in the autoimmune diabetes of NOD strain mice. The M genes are regulated in a manner similar to classical class II genes, in that they are upregulated by IFN-gamma in macrophages, and to a lesser extent by IL4 in B cells. When modeled on the crystal structure of the HLA-DR1 class II molecule, nearly all of the differences between M beta 1 and M beta 2 affect residues facing away from the putative peptide binding groove.

Expression of apogens and engulfens during programmed cell death in the nervous system of the chick embryo

Two categories of cell death related to antigens, apogens and engulfens, have been reported to be expressed by apoptotic cells and the cells involved in their engulfment in the immune system, and in mesenchymal tissue in the limb of the chick embryo (ROTTELLO et al., 1994). To determine whether these antigens are also expressed during the process of neuronal death, the distribution of immunoreactivity to both anti-apogen and anti-engulfen antibodies was examined in the spinal cord and the dorsal root ganglia of the chick embryo. Anti-apogen antibodies labeled a sub-population of the profiles of dying cells in regions where cell death was occurring. The extent of labeling by anti-apogens varied from 3% to 70% of the total number of dying profiles depending on the specific antibody used and the neuronal region examined. Immunoreactive labeling by the anti-engulfen antibodies mainly involved large cells that contained debris of dead cells. These results indicate that at least some dying neuronal cells express common antigens that are shared by dying mesenchymal cells during programmed cell death, and that phagocytotic cells of the immune system are involved in the engulfment of neuronal cells that have undergone programmed cell death.

Influence of an anti-angiogenic treatment on 9L gliosarcoma: oxygenation and response to cytotoxic therapy

Tissue oxygen tensions were measured in subcutaneously growing rat 9L gliosarcoma under normal air and carbogen breathing conditions prior to and after i.v. administration of a perflubron emulsion. When these animals were treated with the anti-angiogenic agents TNP-470 and minocycline for 5 days prior to oxygen measurement, tumor hypoxia was decreased compared with untreated tumors. Hypoxia, defined as the percent of pO2 readings < or = 5 mm Hg, was decreased from 71% in untreated air-breathing controls to 34% in animals treated with the anti-angiogenic agents, the perflubron emulsion and carbogen breathing. These effects were manifest in the increased response of the tumor to single-dose (10, 20 and 30 Gy) radiation therapy. Twenty-four hours after treatment with BCNU oxygenation of the tumors was not altered; however, 24 hr after administration of adriamycin oxygenation of the tumors was increased such that hypoxia in adriamycin-treated tumors in animals receiving the perflubron emulsion and carbogen was reduced to 21%. Tumor growth delay in the s.c. tumors was increased by the addition of treatment with the anti-angiogenic agents from day 4 through day 18 post-tumor cell implantation along with BCNU or adriamycin on days 7-11. Administration of the perflubron emulsion and carbogen breathing resulted in increased tumor growth delay with the chemotherapeutic agents alone and in combination with the anti-angiogenic agents. Life span in animals bearing intracranially implanted 9L gliosarcoma progressively increased with administration of the anti-angiogenic agents and then the anti-angiogenic agents and perflubron emulsion/carbogen compared to treatment with BCNU or adriamycin.

A chloroplast homologue of the signal recognition particle subunit SRP54 is involved in the posttranslational integration of a protein into thylakoid membranes

The mechanisms involved in the integration of proteins into the thylakoid membrane are largely unknown. However, many of the steps of this process for the light-harvesting chlorophyll a/b protein (LHCP) have been described and reconstituted in vitro. LHCP is synthesized as a precursor in the cytosol and posttranslationally imported into chloroplasts. Upon translocation across the envelope membranes, the N-terminal transit peptide is cleaved, and the apoprotein is assembled into a soluble "transit complex" and then integrated into the thylakoid membrane via three transmembrane helices. Here we show that 54CP, a chloroplast homologue of the 54-kDa subunit of the mammalian signal recognition particle (SRP54), is essential for transit complex formation, is present in the complex, and is required for LHCP integration into the thylakoid membrane. Our data indicate that 54CP functions posttranslationally as a molecular chaperone and potentially pilots LHCP to the thylakoids. These results demonstrate that one of several pathways for protein routing to the thylakoids is homologous to the SRP pathway and point to a common evolutionary origin for the protein transport systems of the endoplasmic reticulum and the thylakoid membrane.

[The effect of platelet-activating factor antagonists on early bacteria translocation of rat after burn injury]

30% third degree burn model of Wistar rat was used in this experiment. The animals were divided randomly into three groups (normal control, burn, and platelet-activating factor antagonist treatment). After poured E. coli which labelled with acridine orange into intestine, the rats were killed at 6, 12, 24, and 48 hrs postburn, the bacteria in mesentery lymph node (MLN), liver and pulmonary organisms were cultured and counted, also observed by fluorescent microscopy directly. The results showed that, in PAF antagonist (WEB2170) treatment group, the quantity of bacteria in MLN, liver and lung were decreased significantly (P < 0.001). The labelled bacteria in MLN, liver and lung of burn group were 100%, 80.0%, and 50.0% respectively compared with 40.0%, 30.0%, and 20.0% in treatment group. It is suggested that WEB 2170 could protect the intestine from bacteria translocation after burn injury.

GM1 antibody in Guillain-Barre syndrome after Campylobacter jejuni infection

Fecal culture of Campylobacter jejuni was prepared by the method of Skirrow, and serum class specific antibodies (IgG, IgM and IgA) to Campylobacter jejuni and serum class specific antibodies (IgG IgM) to GM1 were prepared with solid phase enzyme linked immunasorbent assay in 16 cases of Guillain-Barre syndrome (GBS), 32 controls with other neurological diseases (disease controls) and 90 normal controls. The results showed that the incidence of Campylobacter jejuni infection, especially recent infections, in the group with Guillain-Barre syndrome was much higher than that in the two control groups, and that the positive rate of GM1 antibody was also much higher in the GBS group than in the two control groups. The results suggest that Campylobacter jejuni infection may be one of the important precipitating factors of Guillain-Barre syndrome and play an important role in the epidemiological pattern of Guillain-Barre syndrome in China. It damages the myelin of peripheral nerves through induction of GM1 antibody production.

Molecular control of life and death

Recent evidence has shown that two of the three key genes in the programmed cell death pathway of Caenorhabditis elegans, ced-9 (a cell death suppressor) and ced-3 (a cell death inducer), encode proteins that share structural and functional similarities with the mammalian proto-oncogene product Bcl-2 and interleukin-1 beta converting enzyme, respectively. These findings reveal key molecules that control life and death decisions in vertebrates.

Interleukin-6-induced serine phosphorylation of transcription factor APRF: evidence for a role in interleukin-6 target gene induction

The cytokine interleukin-6 (IL-6) rapidly activates a latent cytoplasmic transcription factor, acute-phase response factor (APRF), by tyrosine phosphorylation. Activation and DNA binding of APRF are inhibited by inhibitors of protein tyrosine kinases but not serine/threonine kinases. However, immediate-early gene induction by IL-6 and, as we show here, stimulation of the promoters of the genes for alpha 2-macroglobulin, Jun-B, and intercellular adhesion molecule-1 (ICAM-1) are blocked by the serine/threonine kinase inhibitor H7. We now show that IL-6 triggers a delayed phosphorylation of APRF at serine resudues which can be reversed in vitro by protein phosphatase 2A and is also inhibited by H7. Therefore, APRF serine phosphorylation is likely to represent a crucial event in IL-6 signal transduction leading to target gene induction.

Determination of protein binding by in vitro charcoal adsorption

Certain compounds such as SC-52151 have extensive nonspecific adsorption to the ultrafiltration devices or to dialysis membranes and therefore can not be measured by the conventional ultrafiltration or equilibrium dialysis methods. A new method based on charcoal adsorption was developed to overcome this difficulty. Unlike many conventional methods, which are based on the separation of free drug from bound drug under equilibrium conditions, the new method is operated under nonequilibrium conditions and involves measuring the time course of decline of the percentage of bound drug remaining in plasma while the free drug is being removed by charcoal adsorption. Theoretical aspects of the method and the data processing procedure are presented. SC-98A, a compound with minimal nonspecific adsorption to the ultrafiltration membrane, was used to demonstrate the applicability of this method against the ultrafiltration method. Using this method, the protein binding of SC-52151 in human plasma at 1.0 microgram/ml was determined to be in the range of 91.4-97.7% at room temperature.

Glucocorticoids rescue CD4+ T lymphocytes from activation-induced apoptosis triggered by HIV-1: implications for pathogenesis and therapy

OBJECTIVE

During HIV-1 infection, CD4+ T lymphocytes migrate to immune-reactive lymphoid organs where they are infected by the virus and/or killed by apoptosis on immunoregulatory stimuli--a potential mechanism underlying fatal CD4+ T-cell depletion observed in AIDS. This study seeks to determine the effects of glucocorticoids (GCC) on the activation-induced T-cell apoptosis triggered by HIV-1.

METHODS

CD4+ and CD8+ T cells were purified from HIV-negative donor peripheral blood mononuclear cells (PBMC) by positive selection and exposed to HIV-1 (primary isolates). HIV-1-exposed CD4+ and CD8+ T cells as well as PBMC derived from HIV-1-infected patients were cultured with medium alone or anti-CD3 monoclonal antibodies (MAb)/mitogens in the presence or absence of hydrocortisone or prednisolone. Viral infection kinetics were assessed by polymerase chain reaction and viral replication was measured by p24 enzyme-linked immunosorbent assay. Cell survival, apoptosis, T-cell proliferation, blast cell transformation, and interleukin (IL)-2 receptor (CD25) expression were monitored in parallel for each cell population.

RESULTS

Fractionated CD4+ T cells acutely infected by HIV-1 underwent apoptotic death on anti-CD3 MAb/mitogen stimulation. This activation-induced apoptotic cell killing was antagonized by pharmacological doses of prednisolone or hydrocortisone added up to 6 h after stimulation. GCC were also found to be capable of inhibiting the accelerated apoptosis in PBMC (including both CD4+ and CD8+ T-cell fractions) from HIV-1-infected patients. This anti-apoptotic action of GCC overbalanced their downregulatory effect on T-cell proliferation, resulting in an overall improvement of CD4+ T-cell survival in patient PBMC. These effects of GCC were abrogated by the anti-GCC RU 486 and were not associated with significant suppression of CD25 expression and IL-2-dependent T-cell blast transformation; moreover, GCC had no impact on viral infection and replication.

CONCLUSION

GCC exert a receptor-mediated anti-apoptotic activity in mature T cells through both activation-induced and HIV-1-triggered pathways and could be potent inhibitors of T-cell apoptosis in HIV-1-infected patients.

Frequent T:A-->G:C transversions in X-irradiated mouse cells

Ionizing radiation is a known carcinogen and teratogen. However, the point mutations produced by ionizing radiation in mammalian cells have not been fully characterized. Determination of a characteristic spectrum of X-ray-induced mutations in mammalian cells could provide clues to cellular repair processes and could serve as a marker of individual exposure to radiation. Mouse fibroblasts containing in their genome multiple copies of a recoverable lambda phage shuttle vector were used to detect and analyze radiation-induced point mutations in the supF mutation reporter gene. Following fractionated doses of ionizing radiation, a unique mutational spectrum notable for a high proportion of T:A-->G:C transversions (57%) was found. This pattern was distinct from the spectra of UV-induced and spontaneous mutations detected in the same mouse cell assay system (mainly C:G-->T:A transitions). The predominance of T:A-->G:C transversions and the pattern of mutation hot-spots are consistent with a possible role for polymerase beta in the repair of X-ray-damaged DNA. These results may also help to define a distinctive mutational signature of X-ray exposure in mammalian cells.

Collision identification between convex polyhedra using neural networks

Collision identification between convex polyhedra is a major research focus in computer-aided manufacturing and path planning for robots. This paper presents a collision-identification neural network (CINN) to identify possible collisions between two convex polyhedra. It consists of a modified Hamming net and a constraint subnet. The modified Hamming net is designed for point-to-polyhedron collision identification, and the constraint subnet is designed to move a point within a polyhedron and detect possible collisions with another polyhedron. A CINN has a simple canonical structure. It is very easy to program and can be implemented by a modest number of nonlinear amplifiers and three analog integrators. The working principle of the CINN is very similar to the well-known Hopfield net model. Its simple collective computing power accomplishes the relatively complicated task of collision identification between convex polyhedra, rendering a suitable device for online path planning of robots. An example is presented to demonstrate the application of CINN's to collision-free motion planning.

N-Methyl-beta-carboline-3-carboxamide (FG 7142), an anxiogenic agent in airborne particles and cigarette smoke-polluted indoor air

beta-Carboline-3-carboxylic acid methylamide (FG 7142), an anxiogenic agent, has been measured in airborne particles, automobile-exhaust particles, incinerator ash, smoke condensate of tree leaves and cigarette-smoke-polluted indoor air by high-performance liquid chromatography. This compound has been detected in indoor as well as outdoor air. The source of this compound in indoor air was determined as cigarette smoke, identified from smoking machine studies. This anxiogenic agent was detected in smoke condensate of tree leaves and incinerator ash from garbage burning plants, but not in diesel-exhaust particles. Considering the present results, together with the previous finding that cigarette smoke contains this compound, FG 7142 is likely to be formed through combustion of plants. Our data also suggest that this compound may be widely distributed in the environment.

[Effect of berberine on transit time of human small intestine]

Sorbitol was used as a test sugar for the determination of small intestinal transit time (SITT) by means of breath hydrogen test (BHT). After oral administration of 15g sorbitol, breath hydrogen increased markedly (delta H2 > 5 mumol/L) in 26 of 30 subjects. Following ingestion of a mixture of meglucamine diatrizoate and sorbitol by 18 subjects, SITT measured by BHT correlated closely with the simultaneously determined time for the meglucamine diatrizoate in reaching ileo-cecum. The BHT was used to investigate the effect of berberine on SITT in human. SITT in 20 healthy subjects was 71.10 +/- 22.04 min, SITT was significantly delayed to 98.25 +/- 29.03 min after oral administration of the 1.2g of berberine (P < 0.01). This result suggested that the antidiarrheal property of berberine might be mediated, at least in part, by its ability to delay the small intestinal transit.