[Effect of autophagy inhibitor combined with EGFR inhibitor on triple-negative breast cancer MDA-MB-468 and MDA-MB-231 cells]

OBJECTIVE

To investigate the effect of combined administration of autophagy inhibitor 3-methyladenine/bafilomycin A1 and EGFR inhibitor gefitinib on triple-negative breast cancer MDA-MB-468, MDA-MB-231 cells and estrogen receptor-positive MCF-7 cells.

METHODS

All the cells were treated with 3-methyladenine/bafilomycin A1 and/or gefitinib. The effect of autophagy inhibitor and gefitinib on the cell growth was evaluated by MTT assay. Cell apoptosis was detected by flow cytometry. Western blot analysis was used to determine the alteration of autophagy-related protein (such as LC3) and apoptosis-related proteins (such as caspase-3 and caspase-9).

RESULTS

MTT assay showed that the IC50 in the GE+ 3-MA and GE+ BAF groups were (4.1±0.2) μmol/L and (3.8±0.3) μmol/L, significantly lower than that of the gefitinib alone group [(7.0±0.2) μmol/L] in MDA-MB-468 cells (P<0.05). Similarly, the IC50 in the GE+ 3-MA and GE+ BAF groups were (9.7±0.1) μmol/L and (7.7±0.2) μmol/L, significantly lower than that of the gefitinib alone group [(14.7±0.1) μmol/L]in MDA-MB231 cells (P<0.05). The flow cytometry assay revealed that the apoptosis rates of MDA-MB-468 cells in GE, GE+ 3-MA and GE+ BAF groups were (12.43±3.18)%, (23.37±2.71)% and (18.71±2.81)%, respectively. The apoptosis rates of MDA-MB-231 cells of the GE, GE+ 3-MA and GE+ BAF groups were (12.15±1.82)%, (16.94±2.19)% and (33.83±5.92) %, significantly higher than that of the gefitinib alone group (All P<0.05). The apoptosis rates of the MCF-7 cells were not changed significantly among the three groups (P>0.05). Western blot data showed that the expression levels of LC3 and p-Akt were decreased in the combined groups than that of the gefitinib alone group, while the p-PTEN, caspase-3 and caspase-9 were increased.

CONCLUSIONS

Autophagy inhibitor may enhance the sensitivity to gefitinib in MDA-MB-468 and MDA-MB-231 cells by activation of the PTEN/P13K/Akt pathway. Apoptosis in MDA-MB-468 and MDA-MB-231 cells might be enhanced by the combination treatment through caspase cascade.

Chlorpyrifos-induced hormesis in insecticide-resistant and -susceptible Plutella xylostella under normal and high temperatures

Hormesis induced by insecticides at the dosage lower than what ostensibly directly causes death on insects was studied. This paper reports the effects of the in vivo application of varied concentrations of chlorpyrifos (CPF) on Plutella xylostella (DBM). The insecticide concentrations applied included 0.000025-2.5 mg l-1, which are far lower than LC1 (7.2 mg l-1), for the CPF-susceptable (Si) DBM, and 250 mg l-1 which is far below LC1 (1286 mg l-1), for the CPF-resistant (Rc) DBM, as well as LC10- and LC50-doses for both strains. Significant hormesis was found with the 'hermetic-CPFs', i.e., 0.0025 mg l-1 for Si DBM and 2.5 mg l-1 for Rc DBM, at the normal or high temperature either in a 24 h or under a long-term treatment. These doses of CPF significantly stimulated the development and increased the fecundity of Si and Rc DBM at 25°C with approximately 23.5-29.8% activity increase on acetylcholinesterase (AChE) and 30.5-91.3% increase on glutathione S-transferases (GSTs) at 25 or 38°C in 4-24 h. The enzymatic activities were significantly reduced by LC50-CPF at 25°C in vivo, but the inhibition was relieved significantly, if the insects were first subjected to a hormetic-CPF pretreatment. It was remarkable that the average rates of enzymatic activity increase were 67.5-76.6% for AChE and 366-546% for GSTs. Consequently, it was concluded that the hormesis on Si and Rc DBM could be induced by CPF doses far below LC1 at normal or high temperature in short- or long-term treatment. These findings might help to improve the current insect control practices in the field.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

New measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

Correlation between p53 and epidermal growth factor receptor expression in breast cancer classification

This study aimed to explore new opportunities for developing targeted therapy for triple-negative breast cancer (TNBC) by analyzing the significance and association between p53 and epidermal growth factor receptor (EGFR) expression in different molecular subtypes of breast cancer. The clinical and pathological data of 264 patients with breast cancer receiving surgery in our hospital from January 2012 to August 2013 were retrospectively analyzed. According to the expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 (HER2), Ki-67, CK5/6, p53, and EGFR detected by immunohistochemical methods, breast cancer was divided into four molecular subtypes. Then, the expression of p53 and EGFR as well as their correlation in the different subtypes were determined. Among the four subtypes, luminal B breast cancer was the most common type. TNBC and HER2-enriched breast cancer had larger tumor sizes with higher expression of Ki-67 as compared with the luminal types. TNBC had a lower lymph node metastasis rate but higher CK5/6 and EGFR expression than the other three types. The expression of p53 was higher in luminal B, HER2-enriched, and triple-negative breast cancers, and this was positively correlated with the expression of EGFR in TNBC but not in the other subtypes. p53 and EGFR expression was positively correlated in TNBC, which enables us to explore the molecular biological characteristics of TNBC, so as to provide new ideas for the treatment of TNBC.

Correlation analysis of hormone receptors and the expressions of HER-2 and Ki-67 in breast cancer

OBJECTIVE

This study aims to investigate the correlation and clinical significance of hormone receptors and the expressions of HER-2 and Ki-67 in breast cancer primary lesions and lymph node metastatic tissues.

METHODS

83 cases were studied, who were performed breast cancer surgeries and confirmed the ipsilateral axillary lymph node metastasis by the postoperative pathological diagnosis. Immunohistochemical method was used to simultaneously detect the expressions of ER, PR, HER-2 and Ki-67 in the primary lesions and lymph node metastases.

RESULTS

ER exhibited the expression concordance rate as 85.5% in primary lesions and metastases, with significant difference (P = 0.039); the expression concordance rates of PR and HER-2 in primary lesions and metastases were 90.4% and 89.2%, respectively, without significant difference (P = 0.289, 0.180); between the Ki-67-highly-expressed primary lesions and Ki-67-lowly-expressed metastases, the expressions of ER in primary lesions and metastases exhibited statistical significance, with P as 0.031.

CONCLUSIONS

The primary lesions and lymph node metastases had higher consistency, while there was still about 10% patients showed differentiated expression. The simultaneous detection of breast cancer primary lesions and lymph node metastases was still very necessary.

Search for a light sterile neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)<|Δm(41)(2) |< 0.3 eV(2) range. The relative spectral distortion due to the disappearance of electron antineutrinos was found to be consistent with that of the three-flavor oscillation model. The derived limits on sin(2) 2θ(14) cover the 10(-3) eV(2) ≲ |Δm(41)(2)| ≲ 0.1 eV(2) region, which was largely unexplored.

Selecting patients for a second hepatectomy for colorectal metastases: an systemic review and meta-analysis

BACKGROUND

Opinions on the suitability of repeat hepatectomy for patients with recurrent colorectal liver metastases (CRLMs) vary among studies. We conducted a meta-analysis to establish the criteria for selecting the best candidates for a second hepatectomy.

METHODS

Database and manual searches were performed to identify comparative or prognostic studies published up to October 2013. Outcomes of interest included disease characteristics, perioperative outcomes, and long-term survival after initial and second hepatectomies for patients with CRLM. Study quality was appraised using the Newcastle-Ottawa scale and a modified Hayden's score.

RESULTS

A total of 7226 patients from 27 studies were included. Recurrent CRLMs after initial hepatectomy were more likely to be solitary (RR = 0.86, P = 0.045), unilobar (RR = 0.60, P < 0.001), and smaller (WMD = -0.66, P < 0.001). Postoperative morbidity and mortality were comparable between initial and second hepatectomies (RR = 1.10, P = 0.191; RR = 0.78, P = 0.678, respectively). In high-quality studies, patients showed better survival after a second hepatectomy than those after a single hepatectomy (HR = 0.68, P = 0.022). Patients meeting the following six predictors survived longer after second hepatectomy: disease-free survival after initial hepatectomy >1 y (P = 0.034); solitary CRLM at second hepatectomy (P < 0.001); unilobar CRLM at second hepatectomy (P = 0.009); maximal size of CRLM at second hepatectomy ≤ 5 cm (P = 0.035); lack of extrahepatic metastases at second hepatectomy (P < 0.001); and R0 resection at second hepatectomy (P < 0.001).

CONCLUSIONS

Second hepatectomy is a safe and feasible procedure for patients with recurrent CRLM. In fact, in well-selected patients it improves overall survival. The established criteria can help clinicians to select the best candidates for second hepatectomy and to achieve better long-term outcomes after resection.

Knockdown of VEGFR2 inhibits proliferation and induces apoptosis in hemangioma-derived endothelial cells

Angiogenesis is a process of development and growth of new capillary blood vessels from pre-existing vessels. Angiogenic growth factors play important roles in the development and maintenance of some malignancies, of which vascular endothelial growth factor (VEGF)/VEGFR2 interactions are involved in proliferation, migration, and survival of many cancer cells. The aim of this study was to investigate the function of VEGFR2 in human hemangiomas (HAs). Using immunohistochemistry assay, we examined the expression levels of VEGF, VEGFR2, Ki-67, glucose transporter-1 (Glut-1), phosphorylated protein kinase B (p-AKT) and p-ERK in different phases of human HAs. Positive expression of VEGF, VEGFR2, Ki-67, Glut-1, p-AKT and p-ERK was significantly increased in proliferating phase HAs, while decreased in involuting phase HAs (P=0.001; P=0.003). In contrast, cell apoptotic indexes were decreased in proliferating phase HAs, but increased in involuting phase HAs (P&lt;0.01). Furthermore, we used small hairpin RNA (shRNA)-mediated VEGFR2 knockdown in primary HA-derived endothelial cells (HemECs) to understand  the  role  of  VEGF/VEGFR2 signaling. Knockdown of VEGFR2 by Lv-shVEGFR2 inhibited cell viability and induced apoptosis in primary HemECs companied with decreased expression of p-AKT, p-ERK, p-p38MAPK and Ki-67 and increased expression of caspase-3 (CAS-3). Overexpression of VEGFR2 promoted cell viability and blocked apoptosis in Lv-VEGFR2-transfected HemECs. Taken together, our findings demonstrate that, increased expression of VEGFR2 is involved in the development of primary HemECs possibly through regulation of the AKT and ERK pathways, suggesting that VEGFR2 may be a potential therapeutic target for HAs. 

Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay

A measurement of the energy dependence of antineutrino disappearance at the Daya Bay reactor neutrino experiment is reported. Electron antineutrinos (ν¯(e)) from six 2.9  GW(th) reactors were detected with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41 589 (203 809 and 92 912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude sin(2)2θ(13)=0.090(-0.009)(+0.008) and the first direct measurement of the ν¯(e) mass-squared difference |Δm(ee)2|=(2.59(-0.20)(+0.19))×10(-3)  eV2 is obtained using the observed ν¯(e) rates and energy spectra in a three-neutrino framework. This value of |Δm(ee)2| is consistent with |Δm(μμ)2| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.

Observation of electron-antineutrino disappearance at Daya Bay

The Daya Bay Reactor Neutrino Experiment has measured a nonzero value for the neutrino mixing angle θ(13) with a significance of 5.2 standard deviations. Antineutrinos from six 2.9 GWth reactors were detected in six antineutrino detectors deployed in two near (flux-weighted baseline 470 m and 576 m) and one far (1648 m) underground experimental halls. With a 43,000 ton-GWth-day live-time exposure in 55 days, 10,416 (80,376) electron-antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to expected number of antineutrinos at the far hall is R=0.940±0.011(stat.)±0.004(syst.). A rate-only analysis finds sin(2)2θ(13)=0.092±0.016(stat.)±0.005(syst.) in a three-neutrino framework.

TNIP1, SLC15A4, ETS1, RasGRP3 and IKZF1 are associated with clinical features of systemic lupus erythematosus in a Chinese Han population

Systemic lupus erythematosus (SLE) is an autoimmune disease with heterogeneous clinical manifestations influenced by genetic and environmental factors. Five novel susceptibility genes (TNIP1, SLC15A4, ETS1, RasGRP3 and IKZF1) for SLE have been identified in a recent genome-wide association study of a Chinese Han population. This study investigated their relationships with disease subphenotypes, including renal nephritis, photosensitivity, antinuclear antibody (ANA), age at diagnosis, malar rash, discoid rash, immunological disorder, oral ulcer, hematological disorder, neurological disorder, serositis, arthritis and vasculitis. Significant associations were found for the single nucleotide polymorphism rs10036748 of TNIP1 with photosensitivity (odds ratio (OR) = 0.87, p = 0.01) and vasculitis (OR = 1.18, p = 0.04); rs10847697 of SLC15A4 with discoid rash (OR = 1.18, p = 0.02); rs6590330 of ETS1 with SLE of age at diagnosis <20 years (OR = 1.24, p = 8.91 x 10(-5)); rs13385731 of RasGRP3 with malar rash (OR = 1.20, p = 0.01), discoid rash (OR = 0.78, p = 0.02) and ANA (OR = 0.72, p = 0.004); rs4917014 of IKZF1 with renal nephritis (OR = 1.13, p = 0.02) and malar rash (OR = 0.83, p = 0.00038), respectively. The study suggested that these susceptibility genes might not only play important roles in the development of SLE, but also contribute to the complex phenotypes of SLE.

The effect of Malononitrilamides (FK778) on phenotypic properties of human peripheral dendritic cells

BACKGROUND

FK778, a malononitrilamide analogue of lefunomide, is currently a promising immunosuppressive drug. Because the cellular and molecular mechanisms underlying the effects of FK778 are not entirely clarified. We studied its effects on human peripheral dendritic cells.

METHODS

Peripheral blood mononuclear cells (PBMC) from 12 healthy volunteers were isolated by density separation over Ficoll solution. After resuspension in adaptive immunotherapy medium (AIM)-V medium, they were cultured without exogenous growth factors. The study group was treated with FK 778 (50 microg/mL) or Rapamycin (10 ng/mL). The phenotype of dendritic cell was ascertained by indirect immunoflurescence for analysis by flow cytometry.

RESULTS

Compared with the Rapamycin-treated controls, the expressions of CD80, CD83, CD86, HLA-DA, CD54, CD62, CCR5, and CCR7 in the FK778-treated myeloid dendritic cells and the expression of CD80, CD83, CD86, HLA-DA, and CD54 in the FK778-treated plasmacytoid dendritic cells were significantly down-regulated.

CONCLUSION

FK778 inhibited the differentiation and maturation of dendritic cells.

Pennogenin glycosides with a spirostanol structure are strong platelet agonists: structural requirement for activity and mode of platelet agonist synergism

BACKGROUND

Steroidal saponins have long attracted scientific attention, due to their structural diversity and significant biological activities. For example, total steroidal saponins extracted from the rhizome of Paris polyphylla Sm. var. yunnanensis (TSSPs) constitute an effective treatment for abnormal uterine bleeding.

OBJECTIVE

To determine the active constituents in TSSPs and elucidate the mechanisms that underlie their in vivo pharmacologic actions on hemostasis.

METHODS

Steroidal saponins were purified by chromatography, and their effects upon hemostasis and platelet function were evaluated by tail bleeding time in mice and rats, aggregometry, flow cytometry and Western blotting.

RESULTS

TSSPs promoted hemostasis in vivo and dose-dependently induced rat or human platelet aggregation in vitro. Using bioassay-guided separation, four known pennogenin glycosides with a spirostanol structure were identified as the active ingredients of TSSPs. A structure-activity assay showed that the aglycone and sugar moieties of pennogenin glycosides are both essential for their aggregatory activity. Their synergistic actions on platelet aggregation were observed with pennogenin glycosides and with other known platelet agonists, suggesting that these glycosides are platelet agonists. Aggregation in response to the pennogenin glycosides involved alpha(IIb)beta(3) activation, was inhibited by cAMP, was dependent upon extracellular calcium, secreted ADP and thromboxane synthesis, and was mediated by phosphatidylinositol-3-kinase.

CONCLUSION

We identified pennogenin glycosides with a spirostanol structure as the active ingredients of Paris polyphylla Sm. var. yunnanensis in promoting hemostasis in vivo. Their mode of their action on platelets suggests that they represent a new type of platelet agonist.

Active pharmaceutical ingredients and mechanisms underlying phasic myometrial contractions stimulated with the saponin extract from Paris polyphylla Sm. var. yunnanensis used for abnormal uterine bleeding

BACKGROUND

Total steroidal saponins of Paris polyphylla Sm. var. yunnanensis (TSSP) have been widely used in China for the treatment of abnormal uterine bleeding (AUB). But until now, the main active constituents and the mechanisms underlying the pharmacological actions on uterine activity have not been described.

METHODS

Total steroidal saponins were extracted with EtOH and purified by chromatography. In vitro isometric contraction studies were performed using myometrial strips from estrogen-primed or pregnant rats. Intracellular calcium was monitored under a confocal microscope using Fluo-3 AM-loaded myometrial cells.

RESULTS

TSSP dose-dependently induced phasic myometrial contractions in vitro. Experiments with calcium channel blockers or kinase inhibitors demonstrated that the TSSP-stimulated myometrial contraction was mediated by an increase in [Ca(2+)](i) via influx of extracellular calcium and release of intracellular calcium. Through bioassay-guided separation, it was found that total spirostanol saponins exhibited contractile activity in myometrium and Pennogenin-3-O-alpha-L-arabinofuranosyl(1-->4)[alpha-L-rhamnopyranosyl(1-->2)]-beta-D-glucopyranoside (PARG) was identified as the active ingredient of TSSP. Furthermore, the contractile response of rat myometrium to PARG was significantly enhanced with advancing pregnancy.

CONCLUSIONS

These data provide evidence that myometrial contractility stimulated by TSSP results from [Ca(2+)](i) increase and supports the possibility that some spirostanol gylcosides may represent a new type of contractile agonist for the uterus.

Triterpenoids from Cimicifugae rhizoma, a novel class of inhibitors on bone resorption and ovariectomy-induced bone loss

OBJECTIVE

Increasing research suggested that Cimicifugae rhizoma might be protective against osteoporosis. In this study, we investigated the effects of three cycloartane-type triterpenoids isolated from Cimicifugae rhizoma, cimicidol-3-O-beta-D-xyloside (1), cimicidanol-3-O-beta-D-xyloside (2) and acetylacteol-3-O-beta-d-xyloside (3) on bone resorption in vitro and bone loss in ovariectomized (OVX) mice.

METHODS

The activities of the tested compounds on bone resorption were evaluated using three assays, neonatal mouse parietal bone organ culture, osteoclast-like cells (OCLs) formation and pit formation. The effects on bone mineral density (BMD) and uterine weight were examined using OVX mice. Using LC-MS/MS method, the serum concentrations of the triterpenoids were measured in mice serum collected at 0.5, 1, 3, 6 and 12h following its oral administration.

RESULTS

All of the tested compounds exerted the inhibitory effects on bone resorption in bone organ culture, suppressed both of the formation and the resorbing activity of OCLs. Furthermore, a synergistic effect was observed among those compounds. In vivo studies revealed that compounds 1-3 and the mixture of compounds 1-3 prevented the bone loss in OVX mice without affecting uterine weight, and each compound was detected in the mice serum after single oral administration.

CONCLUSIONS

The triterpenoids exerted the inhibitory effects on osteoclastic bone resorption through the suppression of both OCLs formation and the resorbing activity of OCLs, and also showed a significant protective effect on BMD in OVX mice. The present results might provide a new pharmacological potential for the treatment of osteoporosis.

Protein-protein interactions involving inducible nitric oxide synthase

AIM

Nitric oxide (NO) is a signaling and effector molecule that contributes to multiple physiological and pathophysiological processes in the kidney, vasculature, and other tissues. High output NO generation by inducible NO synthase (iNOS) participates in host defense against pathogens and contributes to tissue injury during inflammatory states. Because of its potent reactivity and diffusibility, NO generation by iNOS is subject to multiple levels of regulation, including transcriptional, translational, and post-translational controls, including protein-protein interactions. This review examines the experimental basis for these protein-protein interactions and their known and potential importance for kidney and vascular physiology.

METHODS

Analysis of the biomedical literature in the area.

RESULTS

iNOS interacts with the inhibitory molecules Kalirin and NOS-associated protein 1.10 kd (NAP110), which inhibit iNOS homodimerization, as well as activator proteins, the Rac-GTPases. Interactions with caveolin-1 control the intracellular locale and degradation of iNOS in tumor cells. In polarized epithelial cells, associations of iNOS with the scaffolding protein EBP50 position iNOS in the apical membrane near key ion transport proteins that also interact with EPB50. In addition, protein-protein interactions of proteins governing iNOS transcription function to specify activation or suppression of iNOS induction by cytokines.

CONCLUSION

Interactions of iNOS with a diverse group of heterologous proteins provides a selective mechanism to control the activity, spatial distribution, and proximity of iNOS to intended targets, while potentially limiting autotoxicity to the iNOS-expressing cell.

[The synergistic action of guanghuoxiang volatile oil and sodium artesunate against Plasmodium berghei and reversal of SA-resistant Plasmodium berghei]

OBJECTIVE

To study the synergistic action of a combination of guanghuoxiang volatile oil (B) and sodium artesunate (SA) against Plasmodium berghei (P. b) and the resistance-reversal activity against SA-resistant P. b (P. b SA-R).

METHODS

Mice infected with P. b N or P. b R were treated with a combination of B and SA respectively by 4-day suppressive test method and linear regression to calculate the SD50 of B and SA for each drug alone and in combination (equally effective dose compatibility).

RESULTS

B alone, N:SD50 = 87.64 +/- 19.58(GKD), R:SD50 = 43.24 +/- 7.71(GKD); SA alone, N:SD50 = 0.88 +/- 0.01(MGKD), R:SD50 = 27.69 +/- 0.93(MGKD). B and SA combination, N:B SD50 = 36.89 +/- 4.57(GKD), SA SD50 = 0.39 +/- 0.05 (MGKD); R:B SD50 = 7.40 +/- 1.30(GKD), SA SD50 = 4.21 +/- 0.74(MGKD). The synergistic indexes of B and SA in combination were 2.2 for N and 6.6 for R, respectivly. The multiple of resistance reversal of B vs SA was 6.6. The relative reversal rate was 87.6%.

CONCLUSION

A combination of B and SA may enhance the antimalarial effect against P. b and reverse the SA-resistance of P. b and delay the occurrence of resistance to SA in N.

The selfish brain and the barker hypothesis

1. Brain sparing is a feature of intra-uterine growth retardation (IUGR). This implies that there is a redistribution of metabolic supply so that body growth slows to a greater extent than brain growth. 2. Intra-uterine growth retardation, as evidenced by a low birthweight for gestational age is a predisposing factor for hypertension, cardiovascular disease and diabetes mellitus in adult life. 3. In species like humans, nephrogenesis is complete before birth. In the rat, it is completed shortly after birth. In both species, it can be shown that either undernutrition or IUGR is associated with reduced nephron number. 4. It has been proposed that oligonephropathy results in hyperfiltration, which ultimately leads to glomerulosclerosis and hypertension. The renin-angiotensin system (RAS) is necessary for normal renal development and fetal renal function. In the rat, blockade of the RAS in the first weeks of life by pharmacological agents reduces glomerular number and has been shown to cause hypertension in adult life. Renal denervation reduces the activity of the fetal RAS and also causes abnormal development of the renin-secreting cells. 5. There is tonic renal sympathetic nerve activity in the late gestation fetal sheep. The level of renal sympathetic nerve activity (RSNA) is influenced by the fetal behavioural state. 6. However, interactions between the developing kidney and the developing sympathetic nervous system are poorly understood. On the one hand, renal innervation may be important in the provision of neurotrophic factors that stimulate the development of the RAS and kidney. On the other, high levels of RSNA associated with circulating catecholamines and vasopressin may cause vasoconstriction and limit nephrogenesis. This latter effect could be a predisposing factor to adult hypertension and cardiovascular disease.

Effect of cold on fetal heart rate and its variability

1. The effects of cold saline (25 mL) injected over the fetal skin on fetal heart rate (HR) and HR variability (HRV), measured as the coefficient of variation (CV) in pulse interval (PI) and by power spectral analysis (PSA), were measured in 10 chronically catheterized fetal sheep aged 140-144 days. To determine the extent to which effects on HR and HRV were mediated by the sympathoadrenal neuroendocrine axis and the cardiac vagus, experiments were performed before and after beta-adrenoreceptor blockade with propranolol (n = 12 fetuses) or before and after cardiac vagal blockade with atropine (n = 4 fetuses). 2. Injection of ice-cold saline over the skin caused an immediate rise in mean arterial pressure (MAP) from 46+/-1 to 55+/-1 mmHg (P < 0.001) and HR from 156+/-2 to 182+/-2 b.p.m. (P < 0.001). Heart rate variability, measured as CV of PI, rose from 3.5+/-0.2 to 8.0+/-0.2% (P < 0.001) and total power spectral density (PSD) increased from 78+/-6 to 278+/-16 units (P < 0.001) as measured by PSA. Within 100s, MAP, HR and HRV had returned to baseline. 3. Beta-adrenoreceptor blockade abolished all these changes in HR, HRV and PSD, but had no effect on changes in MAP. Atropine had no demonstrable effect on the responses to cold. 4. Therefore, the increase in fetal MAP, HR and HRV that occurred with stimulation of peripheral thermoreceptors was the result of increased activity of the sympathetic nervous system. Alterations in efferent cardiac vagal tone were not involved in the cardiac response to cold.

Measurement of baroreceptor-mediated effects on heart rate variability in fetal sheep

To determine if alterations in arterial pressure influenced fetal heart rate variability (HRV), experiments were carried out in chronically catheterized fetal sheep aged 128-138 d. Arterial pressure was raised or lowered by intravenous infusion of phenylephrine or sodium nitroprusside, and the effects on heart rate (HR) and HRV were measured (HRV, as the coefficient of variation (CV) in mean pulse interval or by power spectral analysis). Experiments were carried out before and during beta-adrenoceptor blockade with propranolol or before and during cardiac vagal blockade with atropine. There were positive relationships between mean arterial pressure and HRV (slope = 0.074+/-0.001, r = 0.81+/-0.06, p<0.001, measured as the CV of pulse interval) and between mean arterial pressure and power spectral density (slope = 4+/-0.5, r = 0.89+/-0.02, p<0.001) in the frequency range 0.04-0.08 Hz. Beta-adrenoceptor blockade had no effect on these relationships, but they were abolished by cardiac vagal blockade. The sigmoid relationship between fetal HR and mean arterial pressure, i.e. the cardiac baroreflex, was affected, however, by blockade of cardiac sympathetics and abolished by blockade of cardiac vagal activity. Thus, fetal HRV was affected by alterations in arterial pressure, and these effects depended on the integrity of the cardiac vagus, not on alterations in cardiac sympathetic activity. Therefore, although baroreflex control of fetal HR depends on the integrity of both sympathetic and parasympathetic efferent pathways, baroreceptor-induced changes in HRV depend only on the cardiac vagus.

A role for reactive oxygen species in endothelial cell anoikis

When adherent cells, such as epithelial or endothelial cells, are detached and continuously maintained in suspension, they undergo a form of programmed cell death termed anoikis. We demonstrate that coincident with endothelial cell detachment, there is a dramatic rise in the intracellular level of reactive oxygen species (ROS). Reattachment to a solid surface rapidly attenuates the level of ROS. The mitochondria appear to be the major source of the detachment-induced rise in ROS. The change in the intracellular redox state appears to contribute to endothelial anoikis, because treatment with either the cell-permeant antioxidant N-acetylcysteine or the flavin protein inhibitor diphenylene iodonium is demonstrated to reduce oxidant levels and protect against subsequent cell death. Similarly, the endogenous intracellular level of ROS is shown to correlate with the extent of cell death. Finally, we demonstrate that the activities of both caspases and of the c-Jun N-terminal kinases are modulated by the rise in intracellular ROS levels. These results suggest that oxidants serve as signaling molecules and regulators of anoikis.

A method for determining baroreflex-mediated sympathetic and parasympathetic control of the heart in pregnant and non-pregnant sheep

1. The cardiac baroreflex was measured in four non-pregnant and six pregnant ewes before and during beta-adrenoreceptor blockade with propranolol and before and during vagal blockade with atropine. Arterial pressure was raised by phenylephrine and lowered by sodium nitroprusside. The relationships between mean arterial pressure (MAP) and heart rate (HR), between MAP and heart rate variability (HRV) measured as the coefficient of variation (c.v.) of the mean pulse interval (PI), and between MAP and HRV measured by power spectral analysis were determined. 2. The MAP-HR relationship showed that in pregnant ewes the gain of the cardiac baroreflex was reduced when compared with non-pregnant ewes. Threshold and saturation pressures were higher, maximum achievable HR was lower and there was a decrease in the operating range. 3. V-shaped relationships were obtained between MAP and HRV (measured as the c.v. of PI) and between MAP and power spectral density in the frequency range 0.04-0. 08 Hz. Using selective autonomic blockade the negative, or downward, slope of the V shape was shown to be a measure of baroreceptor-induced, sympathetically mediated effects on HRV. The upward, or positive, slope of the V shape was a measure of baroreceptor-induced, vagally mediated effects. Similar results were also obtained from the cardiac power spectrum, but it was less sensitive. The MAP at which the two slopes intersected was the same as the resting MAP. 4. In pregnant ewes, the slope of the downward limb of the V-shaped relationship between HRV (when measured as the c.v. of PI) and MAP was less than in non-pregnant ewes. 5. The relationship between MAP and the coefficient of variation of the mean pulse interval can therefore be used to measure the degree to which baroreceptor-induced sympathetic and parasympathetic activity affects the heart. 6. The resting MAP is the pressure at which the net effect of these sympathetic and parasympathetic influences on the heart is at a minimum. Studies of both the MAP-HR and MAP-HRV relationships in pregnant and non-pregnant sheep show that in pregnant sheep, there is attenuation of baroreceptor-mediated sympathetic effects on the heart.

IL-6 rescues enterocytes from hemorrhage induced apoptosis in vivo and in vitro by a bcl-2 mediated mechanism

Following a hemorrhagic event, damage to the highly metabolic intestinal tissue induces loss of barrier function leading to bacterial escape and LPS contamination of the host. Orally administered IL-6 restores intestinal barrier function following hemorrhage in both rat and mouse models. IL-6 prevents apoptosis in a variety of lymphoid cells and lines, through the activation of the proto-oncogene bcl-2. This communication elucidates the role of the IL-6-bcl-2 interaction in intestinal apoptosis following hemorrhagic shock. Terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling (TUNEL) and p53 immunohistochemical staining were used to examine intestines from mice hemorrhaged and fed saline or IL-6 and enterocytes (IEC-6) exposed to hypoxia and LPS alone or LPS and IL-6 in vitro. In situ hybridization for bcl-2 expression was performed on intestines or enterocytes. Intestinal sections from mice hemorrhaged and fed IL-6 showed reduction in apoptosis and increases in bcl-2 gene expression relative to sections taken from mice hemorrhaged and fed saline. IEC-6 cells exposed to hypoxia and LPS had high numbers of TUNEL staining cells. Subsequent exposure to IL-6 after hypoxia and LPS reduced apoptotic cell numbers and increased bcl-2 gene expression. The data show that exposure of intestinal epithelial cells to IL-6 either by oral administration in hemorrhaged mice or by coculture following hypoxia and LPS treatment results in increased bcl-2 gene expression and reduced damage from apoptosis.