Erythromycin inhibited glycinergic inputs to gastric vagal motoneurons in brainstem slices of newborn rats

BACKGROUND

Motilin has been known to stimulate the motility of digestive organs peripherally via activation of motilin receptors located at gastrointestinal (GI) cholinergic nerve endings and/or smooth muscle cells. Recent studies have indicated that motilin may also promote GI motility via actions in the central nervous system; however the sites of action and the mechanisms are not clear yet. The present study aimed to test the hypothesis that motilin receptor agonist erythromycin alters the synaptic inputs of preganglionic gastric vagal motoneurons (GVMs) located in the dorsal motor nucleus of the vagus (DMV).

METHODS

Gastric vagal motoneurons were retrogradely labeled by fluorescent tracer from the stomach wall of newborn rats. Fluorescently labeled GVMs in DMV were recorded using whole-cell patch-clamp in brainstem slices and the effects of motilin receptor agonist erythromycin on the synaptic inputs were examined.

KEY RESULTS

Erythromycin (100 nmol L(-1), 1 μmol L(-1), 10 μmol L(-1)) significantly inhibited the frequency of glycinergic spontaneous inhibitory postsynaptic currents (sIPSCs) of GVMs and significantly inhibited the amplitude at the concentration of 10 μmol L(-1). These responses were prevented by GM-109, a selective motilin receptor antagonist. In the pre-existence of tetradotoxin (TTX, 1 μmol L(-1)), erythromycin (10 μmol L(-1)) caused significant decreases of the glycinergic miniature inhibitory postsynaptic currents (mIPSCs), in both the frequency and the amplitude. However, erythromycin (10 μmol L(-1)) didn't cause significant changes of the GABAergic sIPSCs.

CONCLUSIONS & INFERENCES

Erythromycin selectively inhibits the glycinergic inputs of GVMs.

Comparative serum proteomic analysis of patients with acute-on-chronic liver failure: alpha-1-acid glycoprotein maybe a candidate marker for prognosis of hepatitis B virus infection

The acute-on-chronic liver failure (AoCLF) caused by hepatitis B virus (HBV) infection remains to be a challenge in clinics with a high mortality rate in China, and it is important to identify biomarkers to foresee the prognosis of patients with HBV. The current study analysed serum proteome changes of acute-on-chronic liver failure as a result of acute exacerbation of chronic hepatitis B infection. Serum samples were collected from normal subjects (NS, n = 8), patients with chronic hepatitis B (CHB, n = 12) and patients with AoCLF (n = 12). After removal of albumin/IgG and ultramembrane centrifugation, serum proteins were separated by two-dimensional gel electrophoresis. Differentially expressed spots were identified by matrix-associated laser desorption ionization time-of-flight tandem mass spectrometry. Through the removal of albumin/IgG and ultramembrane centrifugation, the well-resolved and reproducible two-dimensional gel electrophoresis (2-DE) profiles were obtained. A total of 23 proteins were identified on 2-DE profiles by their differential expression between the three cohorts. Mass spectrometry analysis resulted in the identification of 12 proteins unambiguously. Western blot analysis confirmed the proteomics results that the α1-acid glycoprotein (α1-AGP) levels decrease significantly in plasma of patients with AoCLF, but somewhat decreased in patients with chronic HBV. Further α1-AGP levels in bulk serum samples were measured by immune turbidimetry including normal subjects group (n = 25), acute hepatitis group (n = 36), chronic hepatitis group (n = 52) and AoCLF group (n = 48), the level of α1-AGP in AoCLF groups sharply decrease than other groups. Our study shows that α1-AGP may be a potential plasma biomarker for AoCLF diagnosis because of acute exacerbation of chronic hepatitis B infection.

Transplantation of immortalized human fetal hepatocytes prevents acute liver failure in 90% hepatectomized mice

AIM

The aim of this study was to investigate whether human fetal hepatocytes are amenable to simian virus 40 large T-antigen (SV40Tag) mediated immortalization and whether the immortalized cells rescue mice with acute liver failure induced by 90% hepatectomy.

METHODS

We constructed a retroviral vector expressing a thermolabile mutant SV40Tag for transfer into primary human fetal hepatocytes. We quantitatively detected the synthetic ability for albumin and urea by the immortalized cells, which were subcutaneously inoculated into mice with severe combined immunodeficiency (SCID) to evaluate tumorigenzcity. The immortalized cells were also transplanted into the spleens of mice with acute liver failure.

RESULTS

One clone resulting after selection, referred to as HepCL, was highly differentiated, growing steadily in a chemically defined serum-free medium. HepCL cells were positive for albumin, cytokeratin 18, and cytokeratin 19 immunocytochemical staining. The average synthetic efficacies of HepCL cells for albumin and urea were comparable to that of unmodified primary human fetal hepatocytes. The population doubling time of HepCL cells in the logarithmic growth phase was approximately 17 hours. HepCL cells showed no oncogenicity in immunodeficient mice at 16 months. Mice receiving HepCL cells (G1) and primary human fetal hepatocytes (G2) showed significantly lower blood ammonia levels after 90% hepatectomy. Pairwise comparisons between the 4 groups showed that xenotransplantation of HepCL (G1) or primary fetal hepatocytes (G2) significantly improved survivals of recipient mice.

CONCLUSIONS

HepCL may be useful as a source of hepatic function for cell-based therapeutics in acute liver failure.

Green waxes, adhesives and lubricants

General characteristics of waxes, adhesives and lubricants as well as the recent fundamental investigations on their physical and mechanical behaviour are introduced. The current R&D status for new type/generation of waxes, adhesives and lubricants from natural products is reviewed, with an emphasis on their tribological applications. In particular, some crucial issues and challenges relating to technological improvement and materials development are discussed. Based on the current predicted shortage of energy resources and environmental concerns, prospective research on the development of green waxes, adhesives and lubricants is suggested.

Two-fold elevation of expression of FoxM1 transcription factor in mouse embryonic fibroblasts enhances cell cycle checkpoint activity by stimulating p21 and Chk1 transcription

OBJECTIVES

Forkhead Box M1 (FoxM1) transcription factor regulates expression of cell cycle effective genes and is stabilized by checkpoint kinase 2 (Chk2) to stimulate expression of DNA repair enzymes in response to DNA damage. This study intended to test whether FoxM1 is involved in cell cycle checkpoint pathways.

MATERIALS AND METHODS

Analysis of senescence and cell proliferation in FoxM1 transgenic (TG) mouse embryonic fibroblasts (MEFs) with 2-fold elevation of FoxM1, and overexpression or knockdown of FoxM1 in an inducible FoxM1 expression cell line, or FoxM1 siRNA. Chromatin immunoprecipitation (ChIP), electrophoretic mobility shift assays (EMSA), and cotransfection to determine FoxM1 transcription targets, as well as RNase protection assays and western blot analysis, were performed.

RESULTS

Two-fold elevation of FoxM1 in FoxM1-TG-MEFs resulted in low levels of cell proliferation and increase in permanent cell cycle arrest at early passages (from passage 6 to 9). These phenotypes correlated with increased phosphorylation of p53 on Ser15, elevated expression of cell cycle inhibitor p21 and Chk1 at passage 3. FoxM1 was stabilized in response to DNA damage in MEFs and FoxM1 overexpression induced p21. Knockdown of FoxM1 resulted in decrease in Chk1. ChIP, EMSA and cotransfection assays confirmed that FoxM1 stimulated promoters of p21 and Chk1.

CONCLUSIONS

Chk1 and p21 are direct transcription targets of FoxM1 and FoxM1 participates in transcriptional responses to stress in normal cells.

Angiotensin converting enzyme inhibition blocks interstitial hyaluronan dissipation in the neonatal rat kidney via hyaluronan synthase 2 and hyaluronidase 1

A functional renin-angiotensin system (RAS) is required for normal kidney development. Neonatal inhibition of the RAS in rats results in long-term pathological renal phenotype and causes hyaluronan (HA), which is involved in morphogenesis and inflammation, to accumulate. To elucidate the mechanisms, intrarenal HA content was followed during neonatal completion of nephrogenesis with or without angiotensin converting enzyme inhibition (ACEI) together with mRNA expression of hyaluronan synthases (HAS), hyaluronidases (Hyal), urinary hyaluronidase activity and cortical lymphatic vessels, which facilitate the drainage of HA from the tissue. In 6-8days old control rats cortical HA content was high and reduced by 93% on days 10-21, reaching adult low levels. Medullary HA content was high on days 6-8 and then reduced by 85% to 12-fold above cortical levels at day 21. In neonatally ACEI-treated rats the reduction in HA was abolished. Temporal expression of HAS2 corresponded with the reduction in HA content in the normal kidney. In ACEI-treated animals cortical HAS2 remained twice the expression of controls. Medullary Hyal1 increased in controls but decreased in ACEI-treated animals. Urine hyaluronidase activity decreased with time in control animals while in ACEI-treated animals it was initially 50% lower and did not change over time. Cells expressing the lymphatic endothelial mucoprotein podoplanin in ACEI-treated animals were increased 18-fold compared to controls suggesting compensation. In conclusion, the high renal HA content is rapidly reduced due to reduced HAS2 and increased Hyal1 mRNA expressions. Normal angiotensin II function is crucial for inducing these changes. Due to the extreme water-attracting and pro-inflammatory properties of HA, accumulation in the neonatally ACEI-treated kidneys may partly explain the pathological renal phenotype of the adult kidney, which include reduced urinary concentration ability and tubulointerstitial inflammation.

Impact of the high-definition multileaf collimator on linear accelerator-based intracranial stereotactic radiosurgery

OBJECTIVES

The impact of two multileaf collimator (MLC) systems for linear accelerator-based intracranial stereotactic radiosurgery (SRS) was assessed.

METHODS

68 lesions formed the basis of this study. 2.5 mm leaf width plans served as reference. Comparative plans, with identical planning parameters, were based on a 5 mm leaf width MLC system. Two collimation strategies, with collimation fixed at 0° or 90° and optimised per arc or beam, were also assessed. Dose computation was based on the pencil beam algorithm with allowance for tissue heterogeneity. Plan normalisation was such that 100% of the prescription dose covered 95% of the planning target volume. Plan evaluation was based on target coverage and normal tissue avoidance criteria.

RESULTS

The median conformity index difference between the MLC systems ranged between 0.8% and 14.2%; the 2.5 mm MLC exhibited better dose conformation. The median reduction of normal tissue exposed to ≥100%, ≥50% and ≥25% of the prescription dose ranged from 13.4% to 29.7%, favouring the 2.5 mm MLC system. Dose fall-off was steeper for the 2.5 mm MLC system with an overall median absolute difference ranging from 0.4 to 1.2 mm. The use of collimation optimisation resulted in a decrease in differences between the MLC systems. The results demonstrated the dosimetric merit of the 2.5 mm leaf width MLC system over the 5 mm leaf width system, albeit small, for the investigated range of intracranial SRS targets.

CONCLUSION

The clinical significance of these results warrants further investigation to determine whether the observed dosimetric advantages translate into outcome improvements.

Extraction, isolation and characterization of bioactive compounds from plants' extracts

Natural products from medicinal plants, either as pure compounds or as standardized extracts, provide unlimited opportunities for new drug leads because of the unmatched availability of chemical diversity. Due to an increasing demand for chemical diversity in screening programs, seeking therapeutic drugs from natural products, interest particularly in edible plants has grown throughout the world. Botanicals and herbal preparations for medicinal usage contain various types of bioactive compounds. The focus of this paper is on the analytical methodologies, which include the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations. The common problems and key challenges in the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations are discussed. As extraction is the most important step in the analysis of constituents present in botanicals and herbal preparations, the strengths and weaknesses of different extraction techniques are discussed. The analysis of bioactive compounds present in the plant extracts involving the applications of common phytochemical screening assays, chromatographic techniques such as HPLC and, TLC as well as non-chromatographic techniques such as immunoassay and Fourier Transform Infra Red (FTIR) are discussed.

Expression and release of IL-29 by mast cells and modulation of mast cell behavior by IL-29

BACKGROUND

The role of interleukin (IL)-29 in innate immunity has been recognized recently, and it is regarded as a potent bioactive molecule. However, little is known about its role in the pathogenesis of allergy. Because mast cells are recognized as primary effector cells of allergy, we investigated the potential relationship between IL-29 and mast cells in this study.

OBJECTIVE

To examine the expression of IL-29 in mast cells and the influence of IL-29 on mast cell mediator release and accumulation.

METHODS

Expression of IL-29 in mast cells was determined by double-labeling immunohistochemistry and flow cytometry analysis. Mast cell cell-line was cultured to examine the mediator release, and mouse peritoneal model was employed to observe the mast cell accumulation.

RESULTS

Large proportions of mast cells expressing IL-29 were localized in human tissue including the colon, tonsil and lung. Mast cells can release substantial quantity of IL-29 upon challenge with proteolytic allergens. Extrinsic IL-29 provoked IL-4 and IL-13 release from mast cell line P815 cells through PI3K/Akt and (JAK)/STAT3 signaling pathways, but failed to induce mast cell histamine release from human mast cells. Extrinsic IL-29 also induced mast cell infiltration in mouse peritoneum by a CD18- and ICAM1-dependent mechanism.

CONCLUSION

Mast cell-derived IL-29 has the potential to be involved in the pathogenesis of allergic inflammation.