Electron-rich palladium regulated by cationic vacancies in CoFe layered double hydroxide boosts electrocatalytic hydrodechlorination

Palladium (Pd) is regarded as a promising electrocatalytic hydrodechlorination (EHDC) catalyst for the detoxification of halogenated phenols. Nevertheless, its intrinsic EHDC activity is seriously restricted by the hydrogen evolution reaction (HER), consuming the active hydrogen (H*) for EHDC. Here, we report a defect regulation strategy using cationic vacancies rich CoFeV-LDH with coupling ultrafine Pd nanoparticles that induces optimized electron distribution of Pd to promote EHDC. The experimental and theoretical results reveal that superior EHDC performance of Pd@CoFeV-LDH is attributed to the electron-rich Pd regulated by cationic vacancies in CoFeV-LDH support, driving facile adsorption of halogenated phenols, high water activation ability and H* selectivity for EHDC. Our findings provide a versatile defect-regulating strategy to overcome the challenge in efficiency and selectivity of EHDC process.

Electronic Structure Regulated Nickel-Cobalt Bimetal Phosphide Nanoneedles for Efficient Overall Water Splitting

Transition metal phosphides (TMPs) have been widely studied for water decomposition for their monocatalytic property for anodic or cathodic reactions. However, their bifunctional catalytic activity still remains a major challenge. Herein, hexagonal nickel-cobalt bimetallic phosphide nanoneedles with 1-3 μm length and 15-30 nm diameter supported on NF (NixCo2-xP NDs/NF) with adjusted electron structure have been successfully prepared. The overall alkaline water electrolyzer composed of the optimal anode (Ni0.67Co1.33P NDs/NF) and cathode (Ni1.01Co0.99P NDs/NF) provide 100 mA cm-2 at 1.62 V. Gibbs Free Energy for reaction paths proves that the active site in the hydrogen evolution reaction (HER) is Ni and the oxygen evolution reaction (OER) is Co in NixCo2-xP, respectively. In the HER process, Co-doping can result in an apparent accumulation of charge around Ni active sites in favor of promoting HER activity of Ni sites, and ΔGH* of 0.19 eV is achieved. In the OER process, the abundant electron transfer around Co-active sites results in the excellent ability to adsorb and desorb *O and *OOH intermediates and an effectively reduced ∆GRDS of 0.37 eV. This research explains the regulation of electronic structure change on the active sites of bimetallic materials and provides an effective way to design a stable and effective electrocatalytic decomposition of alkaline water.

P–371 Clinical value assessment between endometrial receptivity array and immune profiling in patients with implantation failure

Study question

To evaluate whether the pregnancy outcomes could be improved in implantation failure patients by endometrial receptivity array, endometrial immune profiling, or a combination of both.

Summary answer

There was no statistical difference between different endometrial receptivity evaluation and treatment in improving the clinical pregnancy rate.

What is known already

Both endometrial receptivity array and endometrial immune profiling were promised to improve the endometrial receptivity and subsequent clinical pregnancy. However, less is known about the efficiency between each other and whether the combination could further enhance their clinical value.

Study design, size, duration

Between November 2019 and September 2020, 143 women with a history of at least two or more consecutive implantation failure in IVF/ICSI treatment in Chengdu Xinan Gynecology Hospital were included. They were divided into three groups: ‘ERA + Immune Profiling’ (n = 70), ‘Immune Profiling’ (n = 41), and ‘ERA’ (n = 32).

Participants/materials, setting, methods

Inclusion criteria were age ≤ 38, with normal uterus and uterine cavity. All patients were suggested to evaluate endometrial receptivity by ERA test (Igenomix, Valencia, Spain) and endometrial immune profiling based on immunohistochemistry simultaneously, who would be free to choose each or both evaluation approaches. Personal Embryo Transfer and/or personal medical care were adopted according to evaluation results. Clinical pregnancy was confirmed by gestational sacs observed under ultrasonography.

Main results and the role of chance

The overall prevalence of displaced window of implantation (WOI) is 84.3%, and nearly 74.8% (83/111) patients were diagnosed as endometrial immune dysregulation. Clinical Pregnancy rate and embryonic implantation rate decreased in the ‘Immune Test’ groups, but without a statistical difference (P = 0.311, and 0.158, respectively). Multivariable logistic regression analysis showed that different endometrial receptivity evaluation and treatment was not associated the clinical pregnancy rate, suggesting the performance of different endometrial receptivity evaluation and treatment is similar in improving the clinical pregnancy rate. Neither the immune profiling (CD56, P = 0.591; FOXP3, P = 0.195; CD68, P = 0.820; CD163, P = 0.926; CD1a, P = 0.561; CD57, P = 0.221; CD8, P = 0.427; CD138 CE, P = 0.372) nor histologic endometrial dating defined by Noyes criteria (P = 0.374) were associated with ERA phases.

Limitations, reasons for caution

Although the selection of evaluation approaches was based on patients’ willingness, the variances of baseline characteristics and immune profiling existed in different groups. The immunological treatment efficacy based on immune profiling was not evaluated before embryo transfer.

Wider implications of the findings: To our knowledge, this is the first study comparing the pregnancy outcomes after two typical endometrial receptivity evaluation approaches. The findings highlight the unsubstitutability for each assessment, indicating that both asynchronous and pathological WOI contribute to implantation failure.

Trial registration number

X2019004

Expression profiling stratifies mesothelioma tumors and signifies deregulation of spindle checkpoint pathway and microtubule network with therapeutic implications

BACKGROUND

Malignant pleural mesothelioma (MPM) is a lethal neoplasm exhibiting resistance to most treatment regimens and requires effective therapeutic options. Though an effective strategy in many cancer, targeted therapy is relatively unexplored in MPM because the therapeutically important oncogenic pathways and networks in MPM are largely unknown.

MATERIALS AND METHODS

We carried out gene expression microarray profiling of 53 surgically resected MPMs tumors along with paired normal tissue. We also carried out whole transcriptomic sequence (RNA-seq) analysis on eight tumor specimens. Taqman-based quantitative Reverse-transcription polymerase chain reaction (qRT-PCR), western analysis and immunohistochemistry (IHC) analysis of mitotic arrest deficient-like 1 (MAD2L1) was carried out on tissue specimens. Cell viability assays of MPM cell lines were carried out to assess sensitivity to specific small molecule inhibitors.

RESULTS

Bioinformatics analysis of the microarray data followed by pathway analysis revealed that the mitotic spindle assembly checkpoint (MSAC) pathway was most significantly altered in MPM tumors with upregulation of 18 component genes, including MAD2L1 gene. We validated the microarray data for MAD2L1 expression using quantitative qRT-PCR and western blot analysis on tissue lysates. Additionally, we analyzed expression of the MAD2L1 protein by IHC using an independent tissue microarray set of 80 MPM tissue samples. Robust clustering of gene expression data revealed three novel subgroups of tumors, with unique expression profiles, and showed differential expression of MSAC pathway genes. Network analysis of the microarray data showed the cytoskeleton/spindle microtubules network was the second-most significantly affected network. We also demonstrate that a nontaxane small molecule inhibitor, epothilone B, targeting the microtubules have great efficacy in decreasing viability of 14 MPM cell lines.

CONCLUSIONS

Overall, our findings show that MPM tumors have significant deregulation of the MSAC pathway and the microtubule network, it can be classified into three novel molecular subgroups of potential therapeutic importance and epothilone B is a promising therapeutic agent for MPM.

Effect of Intrafix® SafeSet infusion apparatus on phlebitis in a neurological intensive care unit: a case-control study

OBJECTIVE

To investigate the effect of the Intrafix(®) SafeSet infusion apparatus on the incidence of phlebitis in patients being intravenously infused in a neurological intensive care unit (ICU).

METHODS

Patients aged > 12 years, with no history of diabetes mellitus and no existing phlebitis, requiring a daily peripheral intravenous infusion of ≥ 8 h with the total period lasting ≥ 3 days, were enrolled. Infusions were performed using the Intrafix(®) SafeSet or normal infusion apparatus. Incidence of phlebitis (scored according to the Infusion Nursing Standards of Practice of the American Infusion Nurses Society) was analysed.

RESULTS

Patients (n = 1545) were allocated to Intrafix(®) SafeSet (n = 709) or normal infusion (n = 836) groups, matched for age, gender and preliminary diagnosis. Incidence of phlebitis was significantly higher using normal infusion apparatus compared with the Intrafix(®) SafeSet (23.4% versus 17.9%, respectively).

CONCLUSION

Intrafix(®) SafeSet infusion apparatus significantly reduced the incidence of phlebitis in patients in the neurological ICU, compared with normal infusion apparatus, and may be suitable for use in routine clinical practice.

Promoter methylation of BRCA1 in triple-negative breast cancer predicts sensitivity to adjuvant chemotherapy

BACKGROUND

BRCA1 function is inactivated through BRCA1 promoter methylation in a substantial number of triple-negative breast cancers. We investigated the impact of BRCA1-methylation status on the efficacy of adjuvant chemotherapy in patients with triple-negative breast cancer or with non-triple-negative breast cancer.

METHODS

BRCA1 promoter methylation was assessed in 1163 unselected breast cancer patients. Methylation was evaluated using a methylation-specific PCR (MSP) assay.

RESULTS

In the subgroup of 167 triple-negative breast cancer patients who received adjuvant chemotherapy, patients with BRCA1-methylated tumors had a superior 10-year disease-free survival (DFS)(78% versus 55%, P = 0.009) and 10-year disease-specific survival (DSS) (85% versus 69%, P = 0.024) than those with BRCA1-unmethylated tumors, and BRCA1 methylation was an independent favorable predictor of DFS and DSS in a multivariate analysis in this subgroup [DFS: hazard ratio (HR) = 0.45; 95% confidence interval (CI) 0.24-0.84; P = 0.019; DSS: HR = 0.43; 95% CI = 0.19-0.95; P = 0.044]. In contrast, in 675 non-triple-negative breast cancer patients who received adjuvant chemotherapy, BRCA1 methylation was an unfavorable predictor of DFS and DSS in univariate analysis (DFS: HR = 1.56; 95% CI 1.16-2.12; P = 0.003; DSS: HR = 1.53; 95% CI = 1.05-2.21; P = 0.026).

CONCLUSIONS

Triple-negative breast cancer patients with BRCA1-methylated tumors are sensitive to adjuvant chemotherapy and have a favorable survival compared with patients with BRCA1-unmethylated triple-negative tumors.

Abstract P3-09-03: microRNAs and Target Gene Networks in Breast Cancer Cell Lines

Background: MicroRNAs (miRNAs) are a class of small endogenous RNA molecules that post-transcriptionally inhibit gene expression. Several miRNAs have been involved in the regulation of several cellular processes during oncogenesis.

Objective: We simultaneously analyzed 18 different breast cancer cell lines (BCC) for miRNA and mRNA expression profiles in order to identify regulatory miRNA target gene networks and novel miRNA-directed therapeutic targets.

Materials and Methods: We preprocessed the mRNA and miRNA expression data using R software (justRMA) and performed quantile normalization using background-subtracted log ratio distributions across arrays. We identified 39 hsa-miRNAs with the largest variation across samples and examined the Spearman correlations of miRNAs with the Affymetrix probesets. We calculated false discovery rates for probe sets with stringent correlation coefficients. We performed hierarchical clustering using the 39 miRNAs and correlated dendograms branches with basal/luminal classes. Potential miRNA target genes were identified. We performed pathway analyses by using all 39 miRNA target genes. Western blot analyses were performed to confirm regulation of specific proteins. Results: We demonstrated 39 deregulated miRNAs and 10612 mRNA targets genes in BCC. Twenty-three miRNAs were upregulated in basal and downregulated in the luminal groups targeting 6790 genes, and 16 miRNAs downregulated in basal and upregulated in luminal cells, targeting 3822 genes. The first direct comparison screening for the 39 miRNAs and all mRNAs identified 29 direct pairs where the correlation magnitude was above 0.9. MiR-221/222, -31, -143/145, -34a, -200 were the most and consistently deregulated miRNAs in all luminal and basal like BCC. We identified genes, such as CD59, PDGF-β and discoidin domain receptor tyrosine kinase 1-DDR1 and different cancer network pathways, such as cell cycle and cell surface markers, potentially regulated by a subset of these miRNAs. Interestingly, we found that the expression of single genes might be regulated by several miRNAs.

Conclusions: We found a specific miRNA signature and respective genome targets that well defined different clusters of BCC. Breast cancer cell lines are associated with changes in expression of multiple miRNAs that, in turn, disrupt a network of genes that either activate or inhibit important cellular functions. A better understanding of the network of genes and cellular pathways regulated by these miRNAs will enable to understand breast cancer pathogenesis and miRNA based breast cancer therapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-09-03.

Experimental Research on Wild-type p53 Plasmid Transfected into Retinoblastoma Cells and Tissues using an Ultrasound Microbubble Intensifier

The transfection efficiency of wild-type p53 ( wtp53) was investigated in retinoblastoma (RB) Y79 cells using an ultrasound microbubble technique. A human RB nude mouse xenograft tumour model was also used to investigate whether this technique could deliver wtp53 into solid tumours. Reverse transcription–polymerase chain reaction (RT–PCR) demonstrated that wtp53 was successfully transfected into Y79 cells in the plasmid with microbubbles and ultrasound group and in the plasmid with liposomes group, but not in the plasmid with ultrasound group or in the untreated control group. Flow cytometry showed that apoptosis was highest in the microbubbles and ultrasound group (25.58%) compared with the plasmid with liposomes group (19.50%), and the other two groups (< 10%). RT–PCR also showed that the wtp53 gene was successfully transfected into solid tumours in the plasmid with microbubbles and ultrasound group. This study provides preliminary evidence in support of a potential new approach to RB gene therapy.

Expression of caveolin-1 in tongue squamous cell carcinoma by quantum dots

Quantum dots (QDs) are a new class of fluorescent probes to detect biomarker expression. The role of caveolin-1 (Cav-1) in tongue squamous cell carcinoma (TSCC) is still unknown. This study aimed to investigate the expression profile of Cav-1 in carcinogenesis and development of TSCC by QDs immunofluorescence histochemistry (QDs-IHC) and discuss the relationship between the Cav-1 expression and the clinicopathological outcomes. QDs-IHC was used to detect Cav-1 expression in tissue microarrays including normal tongue mucosa (NTM; n=10), hyperplastic tongue mucosa (HTM; n=10), tongue pre-cancer lesions (TPL; n=15) and primary tongue squamous cell carcinoma (PTSCC; n=61). Correlations between the Cav-1 expression and clinicopathologic variables were evaluated statistically. Cells positive for Cav-1 were clearly detected and bright images were obtained in a fine, granular pattern at the cell membrane and cytoplasm using QDs-IHC. The rate of Cav-1 immunoreactivity increased progressively from NTM (0%), HTM (0%), TPL (36%) to PTSCC (74%). When compared with each other, there was statistical significance among PTSCC, TPL and NTM as well as among PTSCC, TPL and HTM. Moreover, Cav-1 expression level in PTSCC was correlated positively with clinical stage and histologic grade. QDs-IHC could accurately detect protein location in tongue mucosa. An increased expression of Cav-1 in the stepwise carcinogenesis from NTM, HTM, TPL to PTSCC suggested that Cav-1 might be an oncogene in the development of tongue squamous cell carcinoma.

Use of quantum dots to detect human papillomavirus in oral squamous cell carcinoma

OBJECTIVE

To examine the association of oral squamous cell carcinoma with human papillomavirus (HPV) using quantum dots (QD) in situ hybridization (ISH).

METHODS

Expression of HPV16/18 was analyzed in a representative collection of 21 oral squamous cell carcinomas by tissue microarrays. The presence of HPV16/18 high risk was detected by applying QDISH which is compared with conventional ISH.

RESULTS

Seven cases out of 21 (33.3%) were positive for QDISH while 1 out of 21 (4.8%) was positive for ISH, although all of HPV DNA were localized in the nuclei in the spinous and basal cell layer of the epithelium. The difference between these two methods was significant (P < 0.05).

CONCLUSIONS

These results demonstrate that the QD might be an efficient method for determination of HPV infection and HPV-associated oral squamous cell carcinoma.

[The change in plasma concentration of free amino acids during early postburn stage in severely scalded rats]

OBJECTIVE

To investigate the rule of the change in plasma concentration of free amino acids during early postburn stage in severely scalded rats, so as to provide assistance for the study of postburn abnormal metabolism of skeletal muscle.

METHODS

Male Wistar rats inflicted by 30% TBSA III degree scalding were employed as the model and were randomly divided into normal (C), 2 postburn hour (PBH), 6PBH, 12PBH and 24PBH groups, with 8 rats in each group. Plasma concentrations of free amino acids was determined by automatic amino acid analyzer. At the same time, the plasma contents of alanine aminotransferase (ALT), aspartate aminotransferase (AST), cortisol, TNF and IL-6 were also assayed.

RESULTS

There was adecreasing tendency in varying degrees in plasma concentration of all amino acids at each time points within 24 PBHs although there was no obvious difference in total amino acids content at each time point. The plasma level of BCAA decreased evidently at 2 PBH and increased obviously at 12 PBH, while the plasma levels of aromatic amino acids (AAA) increased evidently at 12 and 24 PBHs. In addition, the BCAA/AAA ratio showed no change. The ratio of phenylalanine to tyrosine increased significantly at all postburn time points except that of 2PBH. The plasma levels of ALT, AST increased obviously at all postburn time points (P < 0.01). Plasma cortisol levels in all scalding groups were markedly higher than that in C group (P < 0.01), and reached peak level at 12 PBH. Plasma contents of TNFalpha and IL-6 increased significantly (P < 0.01). Whereas the changes in IL-6 and cortisol were obviously and positively correlated to the changes in 3 -- mH and Phe/Tyr.

CONCLUSION

There were significant changes in plasma contents of free amino acids during early postburn stage in scalded rats, which might be related to the early excessive release of inflammatory mediators and enhanced degradation of skeletal muscle and impairment of hepatic function. The mechanism of the change needs to be further studied.

Successful treatment of invasive burn wound infection with sepsis in patients with major burns

OBJECTIVE

To investigate the clinical characteristics of invasive burn wound infection with sepsis in patients with major burns and to summarize the successful experiences in the treatment of such patients.

METHODS

Eight patients with major burns, complicated by invasive burn would infection and sepsis were consecutively admitted to our hospital from September 1997 to October 1998. Among them, 6 patients developed multiple organ dysfunction syndrome (MODS) and 2 developed septic shock. The plasma concentrations of IL-6, IL-8, TNF alpha and lypopolysaccharide (LPS) were assayed before and after surgical intervention, as well as when the patient's vital signs became stable.

RESULTS

The patients' conditions usually deteriorated abruptly when extensive invasive burn wound infection emerged. While multi-microbial infection was usually found, Pseudomonas aeruginosa was the predominant bacteria isolated from the subeschar tissue. The plasma concentrations of IL-6, IL-8, TNF alpha and LPS before surgical intervention were significantly higher than those after surgical intervention (P < 0.05). The lowest levels of the inflammatory mediators were observed when the patients' conditions became stable, and the values were significantly lower than those before surgical intervention (P < 0.001).

CONCLUSION

Since the main cause of burn wound sepsis is the presence of a large area of infected burn wound, they should be excised and covered as early as possible. LPS and pro-inflammatory mediators play an important role in the pathogenesis of burn sepsis. Although favorable results should be attributed to comprehensive treatment, we believe that early, aggressive and thorough surgical excision of infected burn wounds, followed by sound and complete coverage of the area, play a crucial role.

Heparin-free hemodialysis in the treatment of hypernatremia in severely burned patients

BACKGROUND

Hypernatremia in severely burned patients is associated with high morbidity and mortality rates. As the causes of hypernatremia in major burn patients are still not clear, hemodialysis is the method of choice for the treatment. While hemodialysis is effective for the control of hypernatremia, it can cause bleeding complications that may be fatal for burn patients with extensive wounds and potential gastro-intestinal mucosal damage.

CLINICAL DATA

In the present study heparin-free hemodialysis in which the heparin is firmly absorbed to the haemofiltration membrane, hemophan, dispensed with systemic use of heparin. In two extensively burned patients with burn area of 100% TBSA and 98% TBSA respectively and hypernatremia with serum sodium concentration as high as 169 and 158 mmol/l respectively, heparin-free hemodialysis was performed five times and three times each.

RESULTS

Hypernatremia was satisfactorily corrected with no interference to the coagulation system in the two patients as indicated by clinical observation and biochemical analysis. The patient with burn area of 98% TBSA survived and the patient with burn area of 100% TBSA died of wound coverage failure 6 weeks after injury because of non-availability of autograft.

CONCLUSION

Heparin-free hemodialysis is an effective and safe method in the treatment of hypernatremia in extensively burned patients.

[The significance of the expression of the HSP70 and HSP90 in the intestinal mucosa in scalded rats during early postburn stage]

OBJECTIVE

To investigate the changes in the expression, the tissue contents and the distribution of heat shock protein (HSP) 70 and HSP90 in the intestinal mucosa in scalded rats during early postburn stage and to elucidate the effects of heat shock response of intestinal mucosal cell on burn victim's systemic pathophysiology.

METHODS

The scalded rats were taken as the model. ELISA, immunoblotting analysis and immunohistochemical methods were employed to analyze and study the expression, the tissue contents and the distribution and their functional status of HSP70 and HSP90 in the intestinal mucosa.

RESULTS

(1) The free HSP70 content in the intestinal mucosa exhibited significantly transient decrease in the early postburn stage. (2) The total contents of HSP70 and HSP90 in the intestinal mucosa increased obviously postburn. (3) There exhibited remarkable heterogeneity of the molecular structure of HSP70 in the intestinal mucosa in the early postburn stage.

CONCLUSION

The expression and the changes in the contents and the tissue distribution of the two HSPs in the intestinal mucosal cell might play important roles in the cellular stress reaction of the intestinal mucosa and even in the intestinal barrier functional mechanism.

[Anisodamine in prevention and treatment of sepsis of severely burned patients]

OBJECTIVE

To observe the preventive effect of anisodamine on possible sepsis of patients with major burns and the effect of anisodamine on patients with sepsis.

METHODS

Forty-two patients with extensive burn admitted to our burn institute from April 1998 to November 1999 were divided randomly into two groups: treatment group (T group) and control group (C group). In the T group, all 20 patients received fluid resuscitation regimen with anisodamine, and in the C group, 22 patients received the regimen with no anisodamine. A tonometry catheter was positioned in the stomach, connecting with the automatic gas analysis machine (Datex-Engstrom Corporation, Dutch) for determining gastric intramucosal pH (pHi). The plasma concentrations of diamine oxidase (DAO) and endotoxin were measured. Correlation analysis between pHi, DAO and endotoxin were made respectively during early stage of postburn. All the parameters in 7 patients with sepsis before and after administration of anisodamine were compared with those in 6 patients with sepsis without use of anisodamine.

RESULTS

The incidence of sepsis in the T group was lower (20.0%) than that in C group (40.9%). The gastric pHi value in the early period of postburn was significantly higher in the T group than in the C group (P < 0.05). Concurrently, the plasma concentrations of DAO and endotoxin were significantly lower in the T group than in the C group (P < 0.05 or 0.01). A significant negative correlation was seen between the gastric pHi and respective values of DAO, endotoxin (P < 0.05 or 0.01). There were a decrease in gastric pHi, and an increase in plasma DAO and endotoxin level in patients with septic episode; however all the parameters after administration of anisodamine were improved compared with those in septic patients without use of anisodamine.

CONCLUSIONS

Intestinal ischemic injury plays an important role in provoking sepsis during early postburn period. Anisodamine is effective in restoring intestinal circulation both in the shock phase and after the development of sepsis.

[Investigation of immunization status in children of floating population in Henan Province]

OBJECTIVE

To understand the immunization status in children of floating population in Henan Province.

METHODS

Floating people was divided into four types based on their geographical distribution and characteristics of settlement and randomly sampled from each type in 17 cities and prefectures of Henan Province. Immunization status was investigated in 2,141 children from floating population by household visits.

RESULTS

Immunization coverage in children of floating population was less than 60% and coverage of complete immunization with four kinds of vaccine was only 32%, far lower than that in local children. Coverage for children in large-size bazaars and construction sites and from peddlers' families was the lowest, 20.8% and 25.1%, respectively, which indicated that immunization for children in floating population had restricted the in-depth development of Expanded Program on Immunization (EPI) in Henan Province. The main reasons for that were floating population had no stable residence and job. The key problems in immunization for floating population at present were their unawareness of EPI, lack of initiative and certain defects in EPI service existed in some areas.

CONCLUSION

It is necessary to strengthen publicity for immunization, to improve the mode of EPI service and to enhance the management in immunization for floating population.

[A study of paclitaxel on inhibiting effects and mechanisms for Lewis lung carcinoma]

BACKGROUND

To research the inhibitory effect and mechanisms of paclitaxel on Lewis lung carcinoma (LLC) of C57BLP6 mice.

METHODS

LLC cells were inoculated subcutaneously into C57BLP6 mice. Paclitaxel (10 mgPkg) was injected intraperitoneally in the treatment group for ten days. Then the growth and metastasis of LLC were observed and the apoptotic characteristics of LLC cells were detected by electron microscopy and flowcytes assay.

RESULTS

The average weights of the tumors in treatment group and control group were (2. 833 +/-0. 074) g and (0. 588 +/-0. 040) g ( P < 0. 01) , the average numbers of lung metastasis were 5. 500 +/-0. 926 and 1. 167 +/-0. 753 ( P < 0. 01) , and the ratio of apoptosis of LLC cells were 9. 002 % and 25. 772 %( P < 0. 01) , respectively. Some typical apoptotic cells and apoptotic bodies were observed through electron microscope.

CONCLUSIONS

Paclitaxel can effectively inhibit the growth , development and metastasis of the implanted LLC in C57BLP6 mice and it can induce apoptosis of the tumor cells apparently.

Effect of extensive excision of burn wound with invasive infection on hypermetabolism in burn patients with sepsis

OBJECTIVE

To evaluate the effect of extensive excision of invasive burn wound infection on hypermetabolic response in burn patients with sepsis.

METHODS

Eight patients with major burn, complicated by invasive burn wound infection and sepsis, were consecutively admitted to our hospital from September 1997 to October 1998. Resting energy expenditures (REEs) were monitored by means of cardiorespiratory diagnostic system (Medical Graphics Corporation, USA) at patients' bedside. Plasma concentration of IL-6, IL-8, TNF-alpha, and LPS were assayed before and after surgical intervention and at the time when the patients' vital signs became stable. Correlation analysis between REEs and IL-6, IL-8, TNF-alpha, and LPS were made, respectively.

RESULTS

A total of 8 treated patients survived. Values of REE before surgical intervention were significantly higher than those after surgical intervention (P < 0.01), and when patients' vital signs became stable the values were significantly lower than those after surgical intervention (P < 0.01). The plasma concentrations of IL-6, IL-8, TNF-alpha, and LPS after excision of invasive burn wound infection were significantly lower than those before surgical intervention (P < 0.05). The lowest levels of these inflammatory mediators were observed when the conditions of patients became stable, and the values were significantly lower than those before surgical intervention (P < 0.001). There was a significant positive correlation between REE level and respective values of plasma IL-6, IL-8, TNF-alpha, and LPS (P < 0.01).

CONCLUSIONS

It seemed that the extensive excision of invasively infected burn wound in patients with major burn should be performed as early as possible to reduce an increased release of inflammatory mediators and to control the hypermetabolic response during sepsis.

Regulation of extracellular adenosine in rat hippocampal slices is temperature dependent: role of adenosine transporters

While a great deal is known about stimuli that can induce the release of adenosine from brain tissue, relatively little is known about the regulation of the basal extracellular concentration of adenosine that is present in the absence of stimulation. Under normal conditions, enough adenosine is present to tonically activate a significant portion of the high-affinity adenosine A1 receptors. The present experiments demonstrated that the estimated basal concentration of extracellular adenosine in rat hippocampal slices maintained at 21 degrees C (430 nM) is approximately twice that at 32 degrees C (220 nM). The sensitivity of presynaptic modulatory adenosine A1 receptors was not significantly different at 21 degrees C or at 32 degrees C. Slices maintained at 21 degrees C also showed a reduced ability to inactivate extracellular adenosine, which reflects a reduction in adenosine transport across cell membranes. This effect appears to be primarily due to a reduction in the function of the equilibrative, dipyridamole-sensitive (ei) adenosine transporter; the nitrobenzylthioinosine-sensitive equilibrative transporter (es transporter) appears to be relatively less affected by temperature than is the ei transporter. These experiments demonstrate that extracellular concentrations of adenosine in the brain are sensitive to temperature, and suggest that some of the neurological effects of hypothermia might be mediated via increased concentrations of adenosine in the extracellular space.

[Impact of intracellular Na+ concentration alteration on intracellular aerobic glycolysis in skeletal muscles in sepsis]

OBJECTIVE

To evaluate the impact of the changes of the intracellular Na+ concentration on the cellular lactate production of different skeletal muscles in septic rats as compared to that of the normal ones.

METHODS

Using septic model of rats, we established the in vitro muscle incubation system with sufficient oxygen supply as well as the NADH fluoremetric method for the detection of trace amount of lactate in the samples. By using the specific Na+ ionorphor--monensin, the distribution of transmembrane Na+ was under control and the lactate production of the muscle cells were measured.

RESULTS

The intracellular glycolysis was activated by increasing of intracellular Na+ probably because of the mechanism of Na+ pump activation. The sensitivity of muscles to monensin varied according to different muscle fiber composition. The mechanism of the aerobic glycolysis activation in sepsis was identical to the roles of monensin in the cells.

CONCLUSION

The increase of the permeability of Na+ in skeletal muscle cells as well as the increment of the intracellular concentration of Na+ can directly lead to the enhancement of muscular aerobic glycolysis and its mechanism plays a significant role in the enhancement of muscular glycolysis in septic states.

NMDA and non-NMDA receptors mediate responses in the primary gustatory nucleus in goldfish

Primary gustatory afferents from the oropharynx of the goldfish, Carassius auratus, terminate in the vagal lobe, a laminated structure in the dorsal medulla comparable to the gustatory portion of the nucleus of the solitary tract in mammals. We utilized an in vitro brain slice preparation to test the role of different ionotropic glutamate receptor subtypes in synaptic transmission of gustatory information by recording changes in field potentials after application of various glutamate receptor antagonists. Electrical stimulation of the vagus nerve (NX) evokes two short-latency postsynaptic field potentials from sensory layers of the vagal lobe. 6,7-Dinitroquinoxaline-2,3-dione and 6-nitro-7-sulphamoylbenzo[f]quinoxaline-2,3-dione, two non-N-methyl-D-aspartate (NMDA) ionotropic receptor antagonists, blocked these short-latency potentials. Slower potentials that were revealed under Mg2+ -free conditions, were abolished by the NMDA receptor antagonist, D(-)-2-amino-5-phosphonovaleric acid (APV). Repetitive stimulation produced short-term facilitation, which was attenuated by application of APV. These results indicate that the synaptic responses in the vagal lobe produced by stimulation of the gustatory roots of the NX involve both NMDA and non-NMDA receptors. An NMDA receptor-mediated facilitation may serve to amplify incoming bursts of primary afferent activity.

[Experimental study on the mechanisms of enhancement of aerobic glycolysis of muscles in burns and sepsis--the verification of the existence and the enhancement of the aerobic glycolysis of muscles in early postburn period and sepsis]

OBJECTIVE

To verify if aerobic glycolysis exists in the muscle cells in normal rats and to analyze the changes in aerobic glycolysis in the muscle cells in the early postburn period and in septic states.

METHOD

Using septic model of rats, we established the in vitro muscle incubation system with sufficient oxygen supply as well as the NADH fluoremetric method for the detection of trace amount of lactate in the samples. Extensor digitorium longus (EDL) and soleus muscles which represent two types of muscle fiber were studied.

RESULTS

In the early postburn period as well as in septic states, the lactate production of muscle cells was significantly elevated as compared to the normal controls even though the muscles were incubated in a fully oxygenated media. The levels of aerobic glyoclysis, as well as its changes in postburn period and in septic states, vary depending on the difference in the fiber composition of the muscles.

CONCLUSION

Muscle cells might develop a kind of metabolic enhancement which is referred to as aerobic glycolysis rather than the metabolic defect which results from tissue hypoperfusion and hypoxia in the early postburn period as well as in septic states. This provides us a special insight to elucidate the mechanisms of the metabolic derangement in the early postburn period and in sepsis.

Excitatory amino acid neurotransmission in the primary gustatory nucleus of the goldfish Carassius auratus

The vagal lobe in goldfish is a laminated structure in the midmedulla responsible for processing vagal gustatory input from the oropharynx. The anatomical arrangement of the vagal lobe is conducive to an in vitro slice preparation for investigating the physiology and pharmacology of primary gustatory fibers. Postsynaptic population responses (N2 and N3) were evoked from sensory layers of the vagal lobe following stimulation of the incoming vagal fibers. Application of 100 microM kynurenic acid, a broad spectrum glutamate receptor antagonist, abolished or significantly decreased the evoked responses. These results indicate that excitatory amino acids are the neurotransmitter at the first relay in the taste pathway in the central nervous system.

Adenine nucleotides undergo rapid, quantitative conversion to adenosine in the extracellular space in rat hippocampus

There are multiple mechanisms by which adenine nucleotides can be released into the extracellular space in brain. Adenine nucleotides are converted extracellularly to adenosine, which then acts on adenosine receptors to elicit physiological responses, but the rate at which this conversion takes place is unknown. In the present experiments, adenine nucleotides were applied to individual hippocampal neurons, and the subsequent activation of a postsynaptic K+ conductance by adenosine A1 receptors was used to determine the rate of adenosine formation. None of the adenine nucleotides tested (cAMP, AMP, ADP, and ATP) activated A1 receptors directly at the concentrations tested (</=200 microM). AMP, ADP, and ATP were all rapidly converted to adenosine, with a T1/2 for ATP conversion to adenosine of approximately 200 msec, and the last step in this pathway (transformation of AMP to adenosine by 5'-nucleotidase) seems to be the rate-limiting step. As we have reported previously, cAMP is converted to adenosine as well, but on a much slower time scale than any of the other nucleotides tested. These experiments demonstrate that fast, localized release of AMP, ADP, or ATP can result in a transient activation of adenosine receptors but that this is unlikely to occur with cAMP. The existence of a highly active ecto-nucleotidase pathway in brain provides a mechanism for the rapid generation of adenosine after the release of adenine nucleotides into the extracellular space.

The role of cyclic AMP as a precursor of extracellular adenosine in the rat hippocampus

Extracellular adenosine 3':5'-cyclic monophosphate (cAMP) is a potential source of the inhibitory neuromodulator adenosine in the brain. Previous work has demonstrated that cAMP, which is formed intracellularly, can be transported into the extracellular space and subsequently catabolized to adenosine. However, the physiological conditions under which cAMP release might lead to adenosine formation and activation of adenosine receptors are not well understood. In this study we demonstrate that superfusion of hippocampal slices with cAMP or forskolin led to the formation of extracellular adenosine which activated adenosine receptors in a manner comparable to that seen with adenosine superfusion. In contrast, application of brief pulses of cAMP onto the cell bodies of CA1 pyramidal neurons failed to produce an adenosine receptor-mediated response, while application of brief pulses of adenosine or AMP elicited significant responses. These data suggest that large, prolonged increases in extracellular cAMP levels can result in the formation of extracellular adenosine and the activation of adenosine receptors, but brief increases in cAMP levels in the vicinity of individual neurons cannot. These findings imply that increases in cAMP levels may lead to relatively slow increases in extracellular adenosine, as opposed to the fast, spatially restricted increases that would occur following the release of other adenine nucleotides.

Activation of hippocampal adenosine A3 receptors produces a desensitization of A1 receptor-mediated responses in rat hippocampus

The adenosine A3 receptor is expressed in brain, but the consequences of activation of this receptor on electrophysiological activity are unknown. We have characterized the actions of a selective adenosine A3 receptor agonist, 2-chloro-N6-(3-lodobenzyl)-adenosine-5'-N-methyluronamide (Cl-IB-MECA), and a selective A3 receptor antagonist, 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1, 4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS 1191), in brain slices from rat hippocampus. In the CA1 region, activation of A3 receptors had no direct effects on synaptically evoked excitatory responses, long-term potentiation, or synaptic facilitation. However, activation of A3 receptors with Cl-IB-MECA antagonized the adenosine A1 receptor-mediated inhibition of excitatory neurotransmission. The effects of Cl-IB-MECA were blocked by pretreatment with MRS 1191, which by itself had no effect on A1 receptor-mediated responses. The presynaptic inhibitory effects of baclofen and carbachol, mediated via GABA(B) and muscarinic receptors, respectively, were unaffected by Cl-IB-MECA. The maximal response to adenosine was unchanged, suggesting that the primary effect of Cl-IB-MECA was to reduce the affinity of adenosine for the receptor rather than to uncouple it. Similar effects could be demonstrated after brief superfusion with high concentrations of adenosine itself. Under normal conditions, endogenous adenosine in brain is unlikely to affect the sensitivity of A1 receptors via this mechanism. However, when brain concentrations of adenosine are elevated (e.g., during hypoxia, ischemia, or seizures), activation of A3 receptors and subsequent heterologous desensitization of A1 receptors could occur, which might limit the cerebroprotective effects of adenosine under these conditions.