Blocking Notch1 signaling by RNA interference can induce growth inhibition in HeLa cells

The Notch proteins constitute a family of transmembrane receptors that play a pivotal role in cellular differentiation, proliferation, and apoptosis. RNA interference of Presenilin1 (PS1) and Notch1 was carried out in this research to determine whether it could block Notch signaling and induce growth inhibition in HeLa cells. We transfected synthesized target small interfering RNA (siRNA) into HeLa cells, and blocking of Notch signaling was detected by C-promoter binding factor-1 (CBF1) reporter. We then conducted cell proliferation assay. Cells transfected with PS1 and Notch1 siRNA showed great inhibition in proliferation compared to the controls in vitro and in vivo. We conclude that RNA interference of PS1 or Notch1 can block Notch signaling and consequently induce growth inhibition of HeLa cells.

Detecting novel bone density and bone size quantitative trait loci using a cross of MRL/MpJ and CAST/EiJ inbred mice

Most previous studies to identify loci involved in bone mineral density (BMD) regulation have used inbred strains with high and low BMD in generating F(2) mice. However, differences in BMD may not be a requirement in selecting parental strains for BMD quantitative trait loci (QTL) studies. In this study, we intended to identify novel QTL using a cross of two strains, MRL/MpJ (MRL) and CAST/EiJ (CAST), both of which exhibit relatively high BMD when compared to previously used strains. In addition, CAST was genetically distinct. We generated 328 MRL x CAST F(2) mice of both sexes and measured femur BMD and periosteal circumference (PC) using peripheral quantitative computed tomography. Whole-genome genotyping was performed with 86 microsatellite markers. A new BMD QTL on chromosome 10 and another suggestive one on chromosome 15 were identified. A significant femur PC QTL identified on chromosome 9 and a suggestive one on chromosome 2 were similar to those detected in MRL x SJL. QTL were also identified for other femur and forearm bone density and bone size phenotypes, some of which were colocalized within the same chromosomal positions as those for femur BMD and femur PC. This study demonstrates the utility of crosses involving inbred strains of mice which exhibit a similar phenotype in QTL identification.

Characteristics of the m2000 automated sample preparation and multiplex real-time PCR system for detection of Chlamydia trachomatis and Neisseria gonorrhoeae

We evaluated a new real-time PCR-based prototype assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae developed by Abbott Molecular Inc. This assay is designed to be performed on an Abbott m2000 real-time instrument system, which consists of an m2000sp instrument for sample preparation and an m2000rt instrument for real-time PCR amplification and detection. The limit of detection of this prototype assay was determined to be 20 copies of target DNA for both C. trachomatis and N. gonorrhoeae, using serially diluted linearized plasmids. No cross-reactivity could be detected when 55 nongonococcal Neisseria isolates and 3 non-C. trachomatis Chlamydia isolates were tested at 1 million genome equivalents per reaction. Concordance with the Roche Amplicor, BDProbeTec ET, and Gen-Probe APTIMA Combo 2 tests was assessed using unlinked/deidentified surplus clinical specimens previously analyzed with these tests. For C. trachomatis, concordance for positive results ranged from 93.7% to 100%, while concordance for negative results ranged from 98.2% to 100%. For N. gonorrhoeae, concordance for positive and negative results ranged from 91.4% to 100% and 99.3% to 100%, respectively. A workflow analysis of the prototype assay was conducted to obtain information on throughput under laboratory conditions. At 48 samples/run, the time to first result for both C. trachomatis and N. gonorrhoeae was 4.5 h. A total of 135 patient specimens could be analyzed in 8.9 h, with 75 min of hands-on time. This study demonstrated the technical and clinical feasibility of the new Abbott real-time PCR C. trachomatis/N. gonorrhoeae assay.

GPR54 polymorphisms in Chinese girls with central precocious puberty

AIMS

The GPR54 gene has been proved to be important in the process of puberty onset, yet no association study has been performed to evaluate the effect of polymorphisms in the gene on central precocious puberty (CPP). This study was designed to scan for polymorphisms in the GPR54 gene and to investigate the relationships between the genotypes of GPR54 and the disease.

METHODS

272 Chinese Han girls diagnosed to be CPP patients were recruited as the case group and 288 unrelated normal Chinese Han girls as the control group. The whole GPR54 gene was directly sequenced in randomly selected case samples, and the polymorphisms identified were genotyped by ligase detection reaction in both groups. Distributions of the polymorphisms and haplotypes were calculated for statistical evaluation.

RESULTS

Totally 6 polymorphisms were found in sequencing, one of which is a nonsynonymous mutation, while genotyping declared that another SNP located in the promoter region was statistically related to the disease (p = 0.037).

CONCLUSION

One polymorphism in GPR54 gene might be correlated with some cases of CPP, likely by changes in expression of the receptor, but the moderate p value and the lack of functional data make it hard to confirm the correlation. Further studies on the polymorphisms are needed for the exact mechanism.

Catecholamine secretion from rat foetal adrenal chromaffin cells and hypoxia sensitivity

The adrenal medulla chromaffin cells (AMCs) secrete catecholamines in response to various types of stress. We examined the hypoxia-sensitivity of catecholamine secretion by rat foetal chromaffin cells in which the innervation by the splanchnic nerve is not established. The experiments were performed in primary cultured cells from two different ages of foetuses (F15 and F19). Membrane potential of AMCs was monitored with the patch clamp technique, and the catecholamine secretion was detected by amperometry. We found that: (1) AMCs from F19 foetuses showed hypoxia-induced catecholamine release. (2) This hypoxia-induced secretion is produced by membrane depolarization generated by an inhibition of Ca(2+)-activated K(+) current [I (K(Ca))] current. (3) Chromaffin precursor cells from F15 foetuses secrete catecholamine. The quantal release is calcium-dependent, but the size of the quantum is reduced. (4) In the precursor cells, a hypoxia-induced membrane hyperpolarization is originated by an ATP-sensitive K(+) current [I (K(ATP))] activation. (5) During the prenatal period, at F15, the percentage of the total outward current for I (K(ATP)) and I (K(Ca)) was 50 and 29.5%, respectively, whereas at F19, I (K(ATP)) is reduced to 14%, and I (K(Ca)) became 64% of the total current. We conclude that before birth, the age-dependent hypoxia response of chromaffin cells is modulated by the functional activity of K(ATP) and K(Ca) channels.

Effect of pharmacological intakes of zinc and copper on growth performance, circulating cytokines and gut microbiota of newly weaned piglets challenged with coliform lipopolysaccharides

The effect of feeding pharmacological levels of zinc (Zn) and copper (Cu) to newly weaned piglets on growth performance, circulating cytokines levels and gut microbiota was investigated. One hundred eighty piglets [5.90 ± 0.18 kg body weight (BW); six pigs per pen] weaned at 16 to 19 d of age were fed diets containing 3000 ppm additional Zn, 250 ppm additional Cu or a control diet (150 ppm Zn, 15 ppm Cu) for 14 d post-weaning (weeks 1 and 2). Pigs were fed a control diet for an additional 2 wk. Pigs were injected intramuscularly on days 13 and 19 with either 75 μg kg-1 BW of coliform lipopolysaccharide (LPS) or an equivalent amount of saline. Blood samples were collected 3 h after LPS injection to measure plasma levels of cytokines and cortisol. Digesta of ileum and colon were collected from non-challenged pigs on days 14 and 28 to evaluate microbiota using conventional culturing methods and polymerase chain reaction and denaturing gradient gel electrophoresis (PCRDGGE) analysis of the 16S rRNA genes. There were no interactive effects of diet and LPS challenge on growth performance (P > 0.10). Compared with the control, high dietary Zn and Cu increased (P < 0.01) average daily gain (ADG) during weeks 1 (0.125, 0.091 vs. 0.074 kg; P < 0.05) and 2 (0.240, 0.270 vs. 0.155 kg; P < 0.01) only. LPS injection reduced ADG during weeks 2 and 4 (P < 0.01). Dietary treatment did not affect feed efficiency (P > 0.10). Challenging pigs with LPS reduced (P < 0.01) feed efficiency during week 2, but increased (P < 0.05) feed efficiency during week 3. There were no interactive effects between diet and LPS on plasma cytokines levels, except for cortisol (P < 0.05). Plasma levels of cytokines (interleukin-1β, interferon-γ, tumour necrosis factor-α) and cortisol increased (P < 0.01) in pigs challenged with LPS. The high levels of dietary Zn and Cu reduced (P < 0.05) the increases in plasma cortisol level in LPS-challenged pigs at days 9 and 19. There were no differences among the dietary treatments in counts of coliforms and lactobacillus in the digesta from ileum and colon (P > 0.10). PCR-DGGE analysis showed that high levels of dietary Zn and particularly Cu significantly reduced the diversity of ileal microbiota. The effect on microbiota diversity was reversible when dietary Zn and Cu were removed. Enhanced growth performance of the newly weaned piglets fed high dietary Zn and Cu appears mediated via changes in gut microbiota as well as a reduced cortisol response following an immune challenge. Key words: Piglets, zinc, copper, lipopolysaccharide, gut microbiota, cytokines

Expression and bioactivity of recombinant human lysozyme in the milk of transgenic mice

Human milk lysozyme is an important protein for innate immunity, but human breast milk is a fairly poor source for commercial production of this enzyme. Research on the expression of recombinant human lysozyme (rHlys) is therefore potentially valuable to the dairy industry. In this study, 2 different kinds of transgenic mice, PBC-hLY and PBC-sighLY, were generated and used as system models to express rHlys. Six lines of PBC-hLY transgenic mice with human lysozyme genomic DNA-based constructs were generated, and a maximum expression level of rHlys approaching 0.154 mg/mL was achieved. Antibacterial activity of the whey from PBC-hLY female transgenic mice was determined by a turbidimetric assay. Results showed that antibacterial activity of the whey was strongly enhanced, and confirmed that rHlys retained full activity. For rHlys to be secreted efficiently into the milk of transgenic mice, 5 lines of mice were also generated, in which the signal peptide DNA of bovine beta-casein was substituted for that of lysozyme in PBC-hLY transgenic mice. Compared with PBC-hLY transgenic mice, both the expression levels of rHlys and the antibacterial activity of the whey were much higher in the PBC-sighLY transgenic mice. The concentration of rHlys in one of these mice amounted to 1.405 mg/mL-3 times higher than the level in human whey. The antibacterial activity of the whey was also 3 times higher than that of human whey. The rHlys from both PBC-hLY and PBC-sighLY transgenic mice had the same antibacterial activity as human milk lysozyme. The effect of the signal peptide and copy numbers of the transgene on expression of rHlys was also evaluated. This work will certainly permit a better understanding of how mammary gland bioreactor systems can be applied to produce rHlys in other mammals, such as cattle.

Biodegradation of polycyclic aromatic hydrocarbons in the natural waters of the Yellow River: effects of high sediment content on biodegradation

The contamination of polycyclic aromatic hydrocarbons (PAHs) has become one of the major problems in the Yellow River of China. As the Yellow River is the most turbid large river in the world, it remains unknown to which extent the high suspended sediment content in the river may affect the fate and effect of PAHs. Here we report the effect of sediment on biodegradation of chrysene, benzo(a)pyrene and benzo(g,h,i)perylene with phenanthrene as a co-metabolism substrate in natural waters from the Yellow River. Biodegradation kinetics of the PAHs in the river water with various levels of sediment contents were studied in the laboratory by fitting with a biodegradation kinetics model for organic compounds not supporting growth. The results indicated that the biodegradation rates of PAHs increased with the sediment content in the water. When the sediment contents were 0, 4 and 10 g/l, the biodegradation rate constants of chrysene with the initial concentration of 3.80 microg/l were 0.053, 0.084 and 0.111 d(-1), respectively. Further studies suggested the enhanced biodegradation rate in the presence of sediment was caused by the following mechanisms: (1) the population of PAH-degrading bacteria in the water system was found to increase with the sediment content; the bacteria population on sediment phase was far greater than that on water phase during the cultivation process; (2) the sorption of PAHs on the sediment phase was well described by the dual adsorption-partition model. Although the sorption capacity of PAH per unit weight of sediment decreased with the increase of the sediment content, the amount of sorbed PAH increased with the sediment content; and, (3) the desorption of PAHs from the solid phase led to a higher concentration near the water-sediment interface. Since the bacteria were also attached to the interface, this resulted in an increased contact chance between the bacteria and PAHs.

A new spontaneous mutation in the mouse protocadherin 15 gene

We have characterized a new allele of the protocadherin 15 gene (designatedPcdh15(av-6J)) that arose as a spontaneous, recessive mutation in the C57BL/6J inbred strain at Jackson Laboratory. Analysis revealed an inframe deletion in Pcdh15, which is predicted to result in partial deletion of cadherin domain (domain 9) in Pcdh15. Morphologic study revealed normal to moderately defective cochlear hair cell stereocilia in Pcdh15(av-6J) mutants at postnatal day 2 (P2). Stereocilia abnormalities were consistently present at P5 and P10. Degenerative changes including loss of inner and outer hair cells were seen at P20, with severe sensory cell loss in all cochlear turns occurring by P40. The hair cell phenotype observed in the 6J allele between P0 and P20 is the least severe phenotype yet observed in Pcdh15 alleles. However, young Pcdh15(av-6J) mice are unresponsive to auditory stimulation and show circling behavior indicative of vestibular dysfunction. Since these animals show severe functional deficits but have relatively mild stereocilia defects at a young age they may provide an appropriate model to test for a direct role of Pcdh15 in mechanotransduction.

Parasitism of subterranean termites (Isoptera: Rhinotermitidae: Termitidae) by entomopathogenic nematodes (Rhabditida: Steinernematidae; Heterorhabditidae)

In laboratory bioassays, Steinernema riobrave Cabanillas, Poinar and Raulston (355 strain), Steinernema carpocapsae (Weiser) (Mexican 33 strain), Steinernemafeltiae (Filipjev) (UK76 strain), and Heterorhabditis bacteriophora Poinar (HP88 strain) were all capable of infecting and killing three termite species, Heterotermes aureus (Snyder), Gnathamitermes perplexus (Banks), and Reticulitermes flavipes (Kollar) in laboratory sand assays. S. riobrave and S. feltiae caused low levels of Reticulitermes virginicus (Banks) mortality under the same conditions. At 22 degrees C, significant mortality (> or = 80%) of worker H. aureus and G. perplexus was caused by S. riobrave, in sand assays, indicating the need for further study. Because of the short assay time (3 d maximum), reproduction of the nematodes in the target host species was not recorded. All nematode species were observed to develop to fourth-stage juveniles, preadult stages, or adults in all termite species with the exception of R. virginicus. Only S. riobrave developed in R. virginicus. Nematode concentration and incubation time had significant effects on the mortality of worker H. aureus. S. riobrave consistently generated the highest infection levels and mortality of H. aureus in sand assays.

Laparoscopic hepatectomy by curettage and aspiration. Experiences of 62 cases

BACKGROUND

This article introduces a new technique for hepatectomy. Its purpose is to describe the details of laparoscopic hepatectomy by curettage and aspiration (LHCA) and develop a new instrument for this technique.

METHODS

We have performed laparoscopic hepatectomy by curettage and aspiration (LHCA) in 62 patients in our institute between 1998 and 2005: 34 men and 28 women, mean age 47.8 years (range: 26-71 years). Their diagnoses included 18 primary hepatic carcinoma, 2 metastatic carcinoma, 19 intrahepatic duct calculus, and 23 benign entities.

RESULTS

The LHCA operation was completed in 60 patients. In two, the procedure had to be converted to open operation. The mean operative time was 146 min and the mean operative blood loss was 458 ml. Complications occurred in two patients, one with bile leakage and the other with pneumothorax. All the patients were ambulatory within 24 hours of operation. The average length of hospital stay was 1 week.

CONCLUSIONS

Our experience leads us to believe that laparoscopic hepatectomy by curettage and aspiration (LHCA) is a safe and effective technique for resection of liver lesions.

Mitochondrial polymorphisms as risk factors for endometrial cancer in southwest China

It is just in recent years that mitochondrial DNA (mtDNA) mutations have been found in solid tumors. Although a direct link between the presence of mtDNA mutations and the development of tumors has not been made, mtDNA mutations might prove significant in the detection of tumor recurrence and possibly in the detection of genotoxic damage. To investigate the relationship between mtDNA variation and endometrial cancer, we collected blood samples from subjects with Han native background in Yunnan province in China, 49 of them with pathologically conformed endometrial cancer and 31 as controls with no cancer disease and sequenced two hypervariable segments of control region, part of 16sRNA gene, tRNA(leu) (tRNA is transfer RNA) gene and ND1 gene of mtDNA and identified some diagnostic polymorphisms by restriction fragment length polymorphism of coding region of mtDNA. We could not identify the suspected mutations that are related to diabetes and obesity from our endometrial cancer patients. However, our data showed that patients with endometrial cancers clustered in haplogroup D in a significantly higher frequency when compared with controls, implicating a possible association of haplogroup D to endometrial cancer. We concluded that mitochondrial polymorphisms in haplogroup D might play a genetic role in predisposing to endometrial cancer.

PPARr agonist, troglitazone induce growth arrest and apoptosis in MDA-MB-231 human breast cancer cell

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Background: Estrogen receptor (ER)-negative breast carcinomas do not respond to hormone therapy, making their effective treatment very difficult. It is recently reported that peroxisome proliferator-activated receptor-gamma (PPAR-γ) has become a potential target for the prevention and treatment of human cancer. Therefore, PPAR-γ agonist, troglitazone has been extensively studied as a chemopreventive or therapeutic agent in several types of cancer. The purpose of this study was to assess whether troglitazone (TRO) would induce cell growth arrest and apoptosis in MDA-MB-231 (ER-negative) human breast cancer cells. Methods: Cytostatic/cytotoxic effects of troglitazone were measured with MTT assay. The cell cycle distribution was evaluated with flow cytometer. The expression of cyclin-dependent kinase inhibitors, p21, p27, and cell cycle dependent kinases was measured with Western blotting. Apoptotic cells were determined by Hoechst staining and TUNEL assay. Results: Troglitazone inhibited cell proliferation by inducing 65% G0/G1 arrest after 48 h. Accumulation of cells in G0/G1 was accompanied by a decrease of Rb protein phosphorylation associated with reduced activities of cell cycle dependent kinases (CDKs) such as cdk2 and cyclin D. Troglitazone increased the expression cyclin kinase inhibitors, p21 and p27 as MDA-MB-231 cell underwent G0/G1 arrest. Apoptotic effect by troglitazone demonstrated that apoptotic cells elevated from 2.5-fold of the control level at 10 uM, to 3.6-fold at 50 uM and to 4.7-fold at 75 uM. Conclusion: These results indicate that activation of PPAR-gamma with troglitazone induces apoptosis through cell cycle inhibition in estrogen receptor-negative breast cancer cell MDA-MB-231. PPAR-gamma therefore represents a putative molecular target for chemopreventive therapy or inhibition of breast cancer growth.

No significant financial relationships to disclose.

Targeting Src/Stat3 pathway in malignant melanoma

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Background: The Src/Stat 3 pathway has been implicated in the pathogenesis of several malignancies including melanoma. In the current study we evaluated the prevalence of Src and Stat3 activation in human melanoma and the effect of Src inhibitors alone or in combination with chemotherapeutic agents on melanoma cell lines. Methods: Activation of Src was measured by staining for Src-phosphotyrosine 416 (P-Src) and Stat3 by phosphotyrosine 705 Stat3 (P-Stat3). Immunohistochemistry was performed with anti-pStat3-Y705 and anti-pSrc-Y416 antibodies (Cell Signaling, Beverly, MA) on 3 melanoma subtypes. Staining of tumor cells for P-Stat3 was scored by percentage of stained cells as follows: 0 (no staining), 1 (1–25%), 2 (26–50%), 3 (>50%), and intensity 0–3 (0: absent, 1: low, 2: moderate, and 3: high). The sum of these was the composite P-Stat3 score: 0 (0), 1 (1–2), 2 (3–4), and 3 (5–6). P-Src staining was scored by intensity. Melanoma cell lines, A-375, SK-Mel-5 and SK-Mel-28 were exposed to Src inhibitors, SKI-606, PD 180970 and BMS 354825 alone or in combination with standard chemotherapy agents and IC-50 was determined by MTT assay at 24 and 72 hours. Results: 35 biopsies were stained. Median age was 66 years (range 23–90); 60% were women. 48% of all melanoma stained express P-Src; all samples express pStat3. We found a positive correlation between P-Src and P-Stat3 (Spearman coefficient=0.346, p=0.042). 46% stained only for pStat3 and 6% did not stain for either P-Src or P-Stat3. Most positively stained biopsies stained weakly for P-Src and moderately or strongly for pStat3. Src inhibitors inhibited the proliferation of melanoma cell lines; furthermore Src inhibitor treatment synergized with platinum and topoisomerase I inhibitors but not temozolomide. Conclusions: 1) Immunohistochemistry shows variable expression of P-Src and P-Stat3 in human melanoma 2) All tumors staining for P-Src also stain for P-Stat3 and the strength of staining is significantly related. 3) This data may be useful in planning future clinical trials with Src inhibitors in melanoma.

[Table: see text]

[Table: see text]

Circulating endothelial microparticles in acute ischemic stroke: a link to severity, lesion volume and outcome

BACKGROUND

Endothelial membrane microparticles (EMP) in plasma are elevated in several vascular diseases.

OBJECTIVES

To test the hypothesis that EMP would be increased in patients with acute ischemic stroke and would correlate with stroke severity, brain lesion volume and outcome.

PATIENTS AND METHODS

Forty-one patients were studied and divided into two groups based on the National Institutes of Health Stroke Scale (NIHSS) score: 20 patients with mild stroke (NIHSS score < 5) and 21 patients with moderate-severe stroke (NIHSS score > or = 5). Lesion volume was measured using diffusion-weighted magnetic resonance imaging and discharge outcome was based on the discharge Barthel and Rankin scores. Twenty-three age-matched control subjects were also studied. Using flow cytometry, endoglin-positive EMP: CD105+ CD41a-CD45- (E(+)EMP), specific endothelial EMP expressing VE-cadherin and endoglin: CD105+CD144+ (C(+)EMP), EMP expressing phosphatidylserine: CD105+PS+ CD41a- (PS(+)EMP) and EMP expressing ICAM-1: CD105+CD54+ CD45- (I(+)EMP) were analyzed.

RESULTS

Significantly higher PS(+)EMP counts were observed in the group of acute ischemic stroke patients [median 59 (25th-75th percentile: 28-86) MP microL(-1)] relative to the controls [28 (14-36) MP microL(-1)] (P = 0.002). All four EMP phenotypes studied were elevated in the subgroup of moderate-severe stroke patients relative to the controls (all P < 0.05). In the patients with acute ischemic stroke three EMP phenotypes (E(+)EMP, PS(+)EMP and I(+)EMP) correlated significantly with brain lesion volume, with I(+)EMP (P = 0.002) showing the strongest correlation. Admission counts of C(+)EMP (P = 0.0003) and E(+)EMP (P = 0.003) correlated significantly with discharge clinical outcome.

CONCLUSIONS

Certain circulating EMP phenotypes may be associated with severity, lesion volume and outcome of acute ischemic stroke. EMP analysis shows promising contribution to understanding stroke pathophysiology.

Methylation of the insulin-like growth factor binding protein-3 gene and prognosis of epithelial ovarian cancer

Insulin-like growth factor binding protein-3 (IGFBP-3) is a member of the IGFBP family, which regulates the mitogenic and antiapoptotic effects of insulin-like growth factors. Hypermethylation of the IGFBP-3 promoter has been found to suppress its expression. To evaluate the role of IGFBP-3 in ovarian cancer progression, we examined the survival of 235 consecutively selected epithelial ovarian cancer patients in association with IGFBP-3 promoter methylation and IGFBP-3 expression in tumor tissue. IGFBP-3 promoter methylation was analyzed using methylation-specific polymerase chain reaction. Cytosol protein was extracted and measured using a bicinchoninic acid assay; IGFBP-3 was measured by enzyme linked immunosorbent assay. Promoter methylation of the IGFBP-3 gene was detected in 44% (104/235) of patients. IGFBP-3 promoter methylation was associated with disease progression and death after adjusting for clinical and pathologic variables. The association was more evident in patients with early-stage disease: RR = 2.87 (95% CI: 0.78-10.63) for disease progression and RR = 3.94 (95% CI: 0.91-15.78) for death. Tissue levels of IGFBP-3 did not differ by methylation status but were inversely associated with disease stage and residual tumor size. These results suggest that IGFBP-3 promoter methylation may be a useful prognostic marker for disease progression and death in early-stage ovarian cancer.

A rapid HPLC–ESI-MS/MS for qualitative and quantitative analysis of saponins in “XUESETONG” injection

'XUESETONG' injection, one of the most widely used proprietary medicines in traditional Chinese medicine, consists of total saponins made from Panax notoginseng, which is a highly valued and important Chinese medicinal herb. It is used to treat cardiovascular diseases. In order to control the quality of XUESETONG injection, a rapid HPLC-ESI-MS/MS method was developed for qualitative and quantitative determination of the saponins. The analyses were performed on SB-C18 column using gradient elution in 25 min. Full scan and time programmed selected reaction monitoring (SRM) were used for qualitative and quantitative analysis of saponins, respectively. Twenty-seven saponins were identified and nine of them including notoginsenoside R1, ginsenoside Rb1, Rb2, Rb3, Rc, Rd, Re, Rf and Rg1 were quantified. Ten XUESETONG injections were analyzed and compared. The results showed that there is a great variation among different samples. In conclusion, the developed method is rapid, accurate and sensitive for qualitative and quantitative analysis of saponins in XUESETONG injection. Moreover, it also can be used for the quality control of P. notoginseng raw material and its preparations.

Antimicrobial activity of essential oils and structurally related synthetic food additives towards selected pathogenic and beneficial gut bacteria

AIMS

To assess the potential of essential oils and structurally related synthetic food additives in reducing bacterial pathogens in swine intestinal tract.

METHODS AND RESULTS

The antimicrobial activity of essential oils/compounds was measured by determining the inhibition of bacterial growth. Among 66 essential oils/compounds that exhibited > or =80% inhibition towards Salmonellatyphimurium DT104 and Escherichia coli O157:H7, nine were further studied. Most of the oils/compounds demonstrated high efficacy against S. typhimurium DT104, E. coli O157:H7, and E. coli with K88 pili with little inhibition towards lactobacilli and bifidobacteria. They were also tolerant to the low pH. When mixed with pig cecal digesta, these oils/compounds retained their efficacy against E. coli O157:H7. In addition, they significantly inhibited E. coli and coliform bacteria in the digesta, but had little effect on the total number of lactobacilli and anaerobic bacteria.

CONCLUSIONS

Some essential oils/compounds demonstrated good potential, including efficacy, tolerance to low pH, and selectivity towards bacterial pathogens, in reducing human and animal bacterial pathogens in swine intestinal tract.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has identified candidates of essential oils/compounds for in vivo studies to develop antibiotic substitutes for the reduction of human and animal bacterial pathogens in swine intestinal tract.