Five similar anthocyanidin molecules display distinct disruptive effects and mechanisms of action on Aβ1-42 protofibril: A molecular dynamic simulation study

Alzheimer's disease (AD) is associated with the deposition of amyloid-β (Aβ) fibrillary aggregates. Disaggregation of Aβ fibrils is considered as one of the promising AD treatments. Recent experimental studies showed that anthocyanidins, one type of flavonoids abundant in fruits/vegetables, can disaggregate Aβ fibrillary aggregates. However, their relative disruptive capacities and underlying mechanisms are largely unknown. Herein, we investigated the detailed interactions between five most common anthocyanidins (cyanidin, aurantinidin, peonidin, delphinidin, and pelargonidin) and Aβ protofibril (an intermediate of Aβ fibrillization) by performing microsecond molecular dynamic simulations. We found that all five anthocyanidins can destroy F4-L34-V36 hydrophobic core and K28-A42 salt bridge, leading to Aβ protofibril destabilization. Aurantinidin exhibits the strongest damage to Aβ protofibril (with the most severe disruption on K28-A42 salt bridges), followed by cyanidin (with the most destructive effect on F4-L34-V36 core). Detailed analyses reveal that the protofibril-destruction capacities of anthocyanidins are subtly modulated by the interplay of anthocyanidin-protofibril hydrogen bonding, hydrophobic, aromatic stacking interactions, which are dictated by the number or location of hydroxyl/methyl groups of anthocyanidins. These findings provide important mechanistic insights into Aβ protofibril disaggregation by anthocyanidins, and suggest that aurantinidin/cyanidin may serve as promising starting-points for the development of new drug candidates against AD.

A hybrid approach for low-carbon transportation system analysis: integrating CRITIC-DEMATEL and deep learning features

As supply chains, logistics, and transportation activities continue to play a significant role in China's economic and social developments, concerns around energy consumption and carbon emissions are becoming increasingly prevalent. In light of sustainable development goals and the trend toward sustainable or green transportation, there is a need to minimize the environmental impact of these activities. To address this need, the government of China has made efforts to promote low-carbon transportation systems. This study aims to assess the development of low-carbon transportation systems in a case study in China using a hybrid approach based on the Criteria Importance Through Intercriteria Correlation (CRITIC), Decision-Making Trial and Evaluation Laboratory (DEMATEL) and deep learning features. The proposed method provides an accurate quantitative assessment of low-carbon transportation development levels, identifies the key influencing factors, and sorts out the inner connection among the factors. The CRITIC weight matrix is used to obtain the weight ratio, reducing the subjective color of the DEMATEL method. The weighting results are then corrected using an artificial neural network to make the weighting more accurate and objective. To validate our hybrid method, a numerical example in China is applied, and sensitivity analysis is conducted to show the impact of our main parameters and analyze the efficiency of our hybrid method. Overall, the proposed approach offers a novel method for assessing low-carbon transportation development and identifying key factors in China. The results of this study can be used to inform policy and decision-making to promote sustainable transportation systems in China and beyond.

FAM83A promotes the progression and metastasis of human pancreatic neuroendocrine tumors by inducing the epithelial-mesenchymal transition via the PI3K/AKT and ERK pathways

PURPOSE

Family with sequence similarity 83, member A (FAM83A) has been reported to play an important role in cancer progression and metastasis. The purpose of this study was to clarify the role and mechanism of FAM83A in pancreatic neuroendocrine tumors (PanNETs).

METHODS

PanNET specimens and adjacent nontumor pancreatic tissues obtained from 68 patients who underwent curative surgery for PanNETs were assessed for FAM83A expression using immunochemical staining. The relationships between FAM83A expression, clinicopathological parameters and prognosis were statistically analyzed. PanNET cell lines were used to study the role of FAM83A in the progression and metastasis of PanNETs in vitro and in vivo.

RESULTS

FAM83A was overexpressed in PanNET specimens compared with adjacent nontumor tissues. Furthermore, FAM83A expression was closely associated with lymph node metastasis (P = 0.02), perineural invasion (P = 0.001), WHO classification (P = 0.039), AJCC stage (P = 0.01) and shorter disease-free survival in patients with PanNETs (P < 0.001). FAM83A overexpression effectively promoted PanNET cell proliferation, migration, invasion and growth both in vitro and in vivo, whereas FAM83A inhibition exerted the opposite effects. Subsequent mechanistic investigations revealed that FAM83A promotes the progression and metastasis of PanNETs by inducing epithelial-mesenchymal transition (EMT) via the PI3K/AKT and ERK pathways.

CONCLUSIONS

FAM83A plays an important role in the progression and metastasis of PanNET by inducing the EMT via the activation of the ERK and PI3K/AKT pathways and may serve as a valuable molecular target in PanNET treatment.

Dissecting the Inhibitory Mechanism of the αB-Crystallin Domain against Aβ42 Aggregation and Its Effect on Aβ42 Protofibrils: A Molecular Dynamics Simulation Study

Alzheimer's disease (AD) is related to the misfolding and aggregation of amyloid-β (Aβ) protein, and its major pathological hallmark is fibrillary β-amyloid plaques. Impeding the formation of Aβ β-structure-rich aggregates and dissociating Aβ fibrils are considered potent strategies to suppress the onset and progression of AD. As a molecular chaperone, human αB-crystallin has received extensive attention in the inhibition of protein aggregation. Previous experiments reported that the structured core region of αB-crystallin (αBC) exhibits a better preventive effect on Aβ aggregation and toxicity than the full-length protein. However, the molecular mechanism behind the effect of inhibition remains mostly unknown. Herein, we carried out six 500 ns molecular dynamics (MD) simulations to investigate the inhibitory mechanism of αBC on Aβ₄₂ aggregation. Our simulations show that αBC greatly impedes the formation of β-structure contents. We find that the binding of αBC to the Aβ₄₂ monomer is driven by polar, hydrophobic, and H-bonding interactions. To explore whether αBC could destabilize Aβ₄₂ protofibrils, we also carried out MD simulations of Aβ₄₂ protofibrils with and without αBC. The results show that αBC interacts with three binding sites of the Aβ₄₂ protofibril, and the binding is mainly driven by polar and H-bonding interactions. The binding of αBC at these three sites has a preferred dissociation effect on the β-structure content, kink angle, and K28-A42 salt bridges. Overall, this study not only discloses the molecular mechanism of αBC against Aβ₄₂ aggregation but also demonstrates the disruption effects of αBC on Aβ₄₂ protofibrils, which yields an avenue for designing anti-AD drug candidates.

A Comprehensive Insight into the Mechanisms of Dopamine in Disrupting Aβ Protofibrils and Inhibiting Aβ Aggregation

Fibrillary aggregates of amyloid-β (Aβ) are the pathological hallmark of Alzheimer's disease (AD). Clearing Aβ deposition or inhibiting Aβ aggregation is a promising approach to treat AD. Experimental studies reported that dopamine (DA), an important neurotransmitter, can inhibit Aβ aggregation and disrupt Aβ fibrils in a dose-dependent manner. However, the underlying molecular mechanisms still remain mostly elusive. Herein, we investigated the effect of DA on Aβ₄₂ protofibrils at three different DA-to-Aβ molar ratios (1:1, 2:1, and 10:1) using all-atom molecular dynamics simulations. Our simulations demonstrate that protonated DA at a DA-to-Aβ ratio of 2:1 exhibits stronger Aβ protofibril disruptive capacity than that at a molar-ratio of 1:1 by mostly disrupting the F4-L34-V36 hydrophobic core. When the ratio of DA-to-Aβ increases to 10:1, DA has a high probability to bind to the outer surface of protofibril and has negligible effect on the protofibril structure. Interestingly, at the same DA-to-Aβ ratio (10:1), a mixture of protonated (DA⁺) and deprotonated (DA⁰) DA molecules significantly disrupts Aβ protofibrils by the binding of DA⁰ to the F4-L34-V36 hydrophobic core. Replica-exchange molecular dynamics simulations of Aβ₄₂ dimer show that DA⁺ inhibits the formation of β-sheets, K28-A42/K28-D23 salt-bridges, and interpeptide hydrophobic interactions and results in disordered coil-rich Aβ dimers, which would inhibit the subsequent fibrillization of Aβ. Further analyses reveal that DA disrupts Aβ protofibril and prevents Aβ dimerization mostly through π-π stacking interactions with residues F4, H6, and H13, hydrogen bonding interactions with negatively charged residues D7, E11, E22 and D23, and cation-π interactions with residues R5. This study provides a complete picture of the molecular mechanisms of DA in disrupting Aβ protofibril and inhibiting Aβ aggregation, which could be helpful for the design of potent drug candidates for the treatment/intervention of AD.

Molecular mechanisms of resveratrol and EGCG in the inhibition of Aβ42 aggregation and disruption of Aβ42 protofibril: similarities and differences

The aggregation of amyloid-β protein (Aβ) into fibrillary deposits is implicated in Alzheimer's disease (AD), and inhibiting Aβ aggregation and clearing Aβ fibrils are considered as promising strategies to treat AD. It has been reported that resveratrol (RSV) and epigallocatechin-3-gallate (EGCG), two of the most extensively studied natural polyphenols, are able to inhibit Aβ fibrillization and remodel the preformed fibrillary aggregates into amorphous, non-toxic species. However, the mechanisms by which RSV inhibits Aβ₄₂ aggregation and disrupts Aβ₄₂ protofibril, as well as the inhibitory/disruptive mechanistic similarities and differences between RSV and EGCG, remain mostly elusive. Herein, we performed extensive all-atom molecular dynamics (MD) simulations on Aβ₄₂ dimers (the early aggregation state of Aβ₄₂) and protofibrils (the intermediate of Aβ₄₂ fibril formation and elongation) in the absence/presence of RSV or EGCG molecules. Our simulations show that both RSV and EGCG can bind with Aβ₄₂ monomers and inhibit the dimerization of Aβ₄₂. The binding of RSV with Aβ₄₂ peptide is mostly viaπ-π stacking interactions, while the binding of EGCG with Aβ₄₂ is mainly through hydrophobic, π-π stacking, and hydrogen-bonding interactions. Moreover, both RSV and EGCG disrupt the β-sheet structure and K28-A42 salt bridges, leading to a disruption of Aβ₄₂ protofibril structure. RSV mainly binds with residues whose side-chains point inwards from the surface of the protofibril, while EGCG mostly binds with residues whose side-chains point outwards from the surface of the protofibril. Furthermore, RSV interacts with Aβ₄₂ protofibrils mostly viaπ-π stacking interactions, while EGCG interacts with Aβ₄₂ protofibrils mainly via hydrogen-bonding and hydrophobic interactions. For comparison, we also explore the effects of RSV/EGCG molecules on the aggregation inhibition and protofibril disruption of the Iowa mutant (D23N) Aβ. Our findings may pave the way for the design of more effective drug candidates as well as the utilization of cocktail therapy using RSV and EGCG for the treatment of AD.

Natural stereoisomeric flavonoids exhibit different disruptive effects and the mechanism of action on Aβ42 protofibril

Our simulations reveal that two enantiomeric catechins display a better disruptive effect on Aβ42 protofibril than their stereoisomer epicatechin. Unexpectedly, we find that catechins adopt both collapsed and extended states, while epicatechin populates only an extended state. Their different protofibril-disruptive effects are mostly attributed to the steric effect caused by the conformational differences.

Serotonin and Melatonin Show Different Modes of Action on Aβ42 Protofibril Destabilization

Alzheimer's disease (AD) is associated with the aberrant self-assembly of amyloid-β (Aβ) protein into fibrillar deposits. The disaggregation of Aβ fibril is believed as one of the major therapeutic strategies for treating AD. Previous experimental studies reported that serotonin (Ser), one of the indoleamine neurotransmitters, and its derivative melatonin (Mel) are able to disassemble preformed Aβ fibrils. However, the fibril-disruption mechanisms are unclear. As the first step to understand the underlying mechanism, we investigated the interactions of Ser and Mel molecules with the LS-shaped Aβ₄₂ protofibril by performing a total of nine individual 500 ns all-atom molecular dynamics (MD) simulations. The simulations demonstrate that both Ser and Mel molecules disrupt the local β-sheet structure, destroy the salt bridges between K28 side chain and A42 COO^-, and consequently destabilize the global structure of Aβ₄₂ protofibril. The Mel molecule exhibits a greater binding capacity than the Ser molecule. Intriguingly, we find that Ser and Mel molecules destabilize Aβ₄₂ protofibril through different modes of action. Ser preferentially binds with the aromatic residues in the N-terminal region through π-π stacking interactions, while Mel binds not only with the N-terminal aromatic residues but also with the C-terminal hydrophobic residues via π-π and hydrophobic interactions. This work reveals the disruptive mechanisms of Aβ₄₂ protofibril by Ser and Mel molecules and provides useful information for designing drug candidates against AD.

Green tea extract EGCG plays a dual role in Aβ42 protofibril disruption and membrane protection: A molecular dynamic study

Amyloid plaques accumulated by the amyloid-β (Aβ) fibrillar aggregates are the major pathological hallmark of the Alzheimer's disease (AD). Inhibiting aggregation and disassembling preformed fibrils of Aβ by natural small molecules have developed into a promising therapeutic strategy for AD. Previous experiments reported that the green tea extract epigallocatechin-3-gallate (EGCG) can disrupt Aβ fibril and reduce Aβ cytotoxicity. The inhibitory ability of EGCG can also be affected by cellular membranes. Thus, it is essential to consider the membrane influences in the investigation of protofibril-disruptive capability of EGCG. Here, we performed multiple all-atom molecular dynamic simulations to investigate the effect of EGCG on the Aβ₄₂ protofibril in the presence of a mixed POPC/POPG (7:3) lipid bilayer and the underlying molecular mechanisms of action. Our simulations show that in the presence of membrane bilayers, EGCG has a preference to bind to the membrane, and this binding alters the binding modes between Aβ₄₂ protofibril and the lipid bilayer, leading to a reduced membrane thinning, indicative of a protective effect of EGCG on the membrane. And EGCG still displays a disruptive effect on Aβ₄₂ protofibril, albeit with a lesser extent of disruption than that in the membrane-free environment. EGCG destabilizes the two hydrophobic core regions (L17-F19-I31 and F4-L34-V36), and disrupts the intrachain K28-A42 salt bridges. Our results reveal that in the presence of lipid bilayers, EGCG plays a dual role in Aβ₄₂ protofibril disruption and membrane protection, suggesting that EGCG could be a potential effective drug candidate for the treatment of AD.

Dental nerves: a neglected mediator of pulpitis

As one of the most densely innervated tissues, the dental pulp contains abundant nerve fibres, including sensory, sympathetic and parasympathetic nerve fibres. Studies in animal models and human patients with pulpitis have revealed distinct alterations in protein expression and histological appearance in all types of dental nerve fibres. Various molecules secreted by neurons, such as classical neurotransmitters, neuropeptides and amino acids, not only contribute to the induction, sensitization and maintenance of tooth pain, but also regulate non-neuronal cells, including fibroblasts, odontoblasts, immune cells and vascular endothelial cells. Dental nerves are particularly important for the microcirculatory and immune responses in pulpitis via their release of a variety of functional substances. Further, nerve fibres are found to be involved in dental soft and hard tissue repair. Thus, understanding how dental nerves participate in pulpitis could have important clinical ramifications for endodontic treatment. In this review, the roles of dental nerves in regulating pulpal inflammatory processes are highlighted and their implications for future research on this topic are discussed.

Green Tea Extracts EGCG and EGC Display Distinct Mechanisms in Disrupting Aβ42 Protofibril

The amyloid beta (Aβ) fibrillar aggregate is the hallmark of Alzheimer's disease (AD). Disassembling preformed fibril or inhibiting Aβ aggregation is considered as a therapeutic strategy for AD. Increasing evidence shows that green tea extracts, epigallocatechin-3-gallate (EGCG, containing an extra gallic acid ester group compared to EGC) and epigallocatechin (EGC), can disassociate Aβ fibrils and attenuate Aβ toxicity. However, the underlying molecular mechanism is poorly understood. Herein, we performed microsecond all-atom molecular dynamics (MD) simulations to investigate the influences of EGCG/EGC on the newly cryo-EM resolved LS-shaped Aβ₄₂ protofibrils and their detailed interactions. MD simulations demonstrate that both EGCG and EGC can disrupt Aβ₄₂ protofibril and EGCG displays a higher disruptive capacity than EGC. EGCG alters the L-shape of Aβ₄₂ protofibril by breaking the hydrogen bond between H6 and E11 through π-π interactions with residues H14/Y10 and hydrogen-bonding interactions with E11, while EGC remodels the L-shape by inserting into the hydrophobic core formed by A2, F4, L34, and V36 and via aromatics interaction with H6/Y10. EGCG disrupts the salt bridges between the K28 side chain and A42 COO^- through hydrogen-bonding interaction with A42 and cation-π interaction between its gallic acid ester group and K28, while EGC damages the salt bridges through hydrophobic interactions with V39 and I41 as well as with I32, M35, and V40 located in the C-terminal hydrophobic core. This study demonstrates the pivotal role of the gallic acid ester group of EGCG in disrupting Aβ₄₂ protofibril and provides atomic-level insights into the distinct mechanism by which EGCG and EGC disrupt Aβ protofibril, which could be useful for designing amyloid inhibitors.

How many lymph nodes should be dissected in esophagectomy with or without neoadjuvant therapy to get accurate staging?

It is essential to dissect an adequate number of lymph nodes (LNs) to ensure staging accuracy during esophagectomy with or without neoadjuvant therapy. We developed a statistical model to quantify the probability of precise nodal staging based on previous studies. Esophageal cancer patients who underwent esophagectomy were retrospectively reviewed in the Surveillance, Epidemiology, and End Results database. A β-binomial distribution was adopted to estimate the number of understaged patients based on the numbers of positive and examined LNs. Using 6,252 patients, we estimated a 90% confidence of accurate N0 staging could be achieved by examining 17 LNs without neoadjuvant therapy. To obtain similar accuracy in N1 and N2, 20 and 25 LNs should be examined. For patients with neoadjuvant therapy, 18, 19, and 28 LNs could achieve the same accuracy. Staging accuracy was a significant prognostic factor. We found when 90% confidence had been achieved, patient survival did not improve with more LNs examined and the ratio and log odds of positive LNs did not have significant prognostic values. The statistical model we developed for precise staging in patients with different N stages is of great value in guiding lymphadenectomy. It provided risk assessment for underestimated LN metastases and guided subsequent adjuvant treatment.

Structural Polymorphism in a Self-Assembled Tri-Aromatic Peptide System

Self-assembly is a process of key importance in natural systems and in nanotechnology. Peptides are attractive building blocks due to their relative facile synthesis, biocompatibility, and other unique properties. Diphenylalanine (FF) and its derivatives are known to form nanostructures of various architectures and interesting and varied characteristics. The larger triphenylalanine peptide (FFF) was found to self-assemble as efficiently as FF, forming related but distinct architectures of plate-like and spherical nanostructures. Here, to understand the effect of triaromatic systems on the self-assembly process, we examined carboxybenzyl-protected diphenylalanine (z-FF) as a minimal model for such an arrangement. We explored different self-assembly conditions by changing solvent compositions and peptide concentrations, generating a phase diagram for the assemblies. We discovered that z-FF can form a variety of structures, including nanowires, fibers, nanospheres, and nanotoroids, the latter were previously observed only in considerably larger or co-assembly systems. Secondary structure analysis revealed that all assemblies possessed a β-sheet conformation. Additionally, in solvent combinations with high water ratios, z-FF formed rigid and self-healing hydrogels. X-ray crystallography revealed a "wishbone" structure, in which z-FF dimers are linked by hydrogen bonds mediated by methanol molecules, with a 2-fold screw symmetry along the c-axis. All-atom molecular dynamics (MD) simulations revealed conformations similar to the crystal structure. Coarse-grained MD simulated the assembly of the peptide into either fibers or spheres in different solvent systems, consistent with the experimental results. This work thus expands the building block library for the fabrication of nanostructures by peptide self-assembly.

Landscape of expression profiles in esophageal carcinoma by The Cancer Genome Atlas data

In this study, we explored the gene and microRNA (miRNA) expressions profile of esophageal carcinoma. The expression data for messenger RNAs and miRNAs in normal and cancerous esophageal tissues were obtained from the Cancer Genome Atlas database and then the differentially expressed genes and miRNAs were identified. As a result, we identified 2962 genes and 45 miRNAs differentially expressed in esophageal carcinoma compared with normal esophageal tissues. Subsequently, the altered gene functions and signaling pathways were investigated using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, and these differentially expressed genes were significantly enriched in the cell cycle, cell migration, mitogen-activated protein kinase (MAPK) and toll-like receptor signaling pathway, and so on. Then the regulatory relationships between the differentially expressed miRNAs and genes were examined with Targetscan and Miranda, and the potential target sites of transcription factors (TFs) in the promoter regions of these miRNAs and genes were identified using the TRANSFAC database. Finally the TF-miRNA-gene network in esophageal cancer was established, summarizing the regulatory links among the TFs, differentially expressed miRNAs and differentially expressed genes. Factors such as core promoter-binding protein (CPBP), nuclear factor of activated T-cells 1 (NFAT-1), miR-30c-5p, were located in the central hub of this network, highlighting their vital roles in esophageal tumorigenesis. These findings may extend our understanding of the molecular mechanisms underlying esophageal carcinoma and promote new perspectives for prevention, diagnosis and treatment.

Conformational dynamics of cancer-associated MyD88-TIR domain mutant L252P (L265P) allosterically tilts the landscape toward homo-dimerization

MyD88 is an essential adaptor protein, which mediates the signaling of the toll-like and interleukin-1 receptors' superfamily. The MyD88 L252P (L265P) mutation has been identified in diffuse large B-cell lymphoma. The identification of this mutation has been a major advance in the diagnosis of patients with aldenstrom macroglobulinemia and related lymphoid neoplasms. Here we used computational methods to characterize the conformational effects of the mutation. Our molecular dynamics simulations revealed that the mutation allosterically quenched the global conformational dynamics of the toll/IL-1R (TIR) domain, and readjusted its salt bridges and dynamic community network. Specifically, the mutation changed the orientation and reduced the fluctuation of α-helix 3, possibly through eliminating/weakening ~8 salt bridges and enhancing the salt bridge D225-K258. Using the energy landscape of the TIR domains of MyD88, we identified two dynamic conformational basins, which correspond to the binding sites used in homo- and hetero-oligomerization, respectively. Our results indicate that the mutation stabilizes the core of the homo-dimer interface of the MyD88-TIR domain, and increases the population of homo-dimer-compatible conformational states in MyD88 family proteins. However, the dampened motion restricts its ability to heterodimerize with other TIR domains, thereby curtailing physiological signaling. In conclusion, the L252P both shifts the landscape toward homo-dimerization and restrains the dynamics of the MyD88-TIR domain, which disfavors its hetero-dimerization with other TIR domains. We further put these observations within the framework of MyD88-mediated cell signaling.

Insights Into the Allosteric Inhibition of the SUMO E2 Enzyme Ubc9

Conjugation of the small ubiquitin-like modifier (SUMO) to protein substrates is an important disease-associated posttranslational modification, although few inhibitors of this process are known. Herein, we report the discovery of an allosteric small-molecule binding site on Ubc9, the sole SUMO E2 enzyme. An X-ray crystallographic screen was used to identify two distinct small-molecule fragments that bind to Ubc9 at a site distal to its catalytic cysteine. These fragments and related compounds inhibit SUMO conjugation in biochemical assays with potencies of 1.9-5.8 mm. Mechanistic and biophysical analyses, coupled with molecular dynamics simulations, point toward ligand-induced rigidification of Ubc9 as a mechanism of inhibition.

Analysis report for osteosarcoma expression profile

BACKGROUND

Osteosarcoma is a kind of highly malignant primary bone tumor which most common in the teenage, and holds strong aggressive, earlier organs metastases mainly to lung, prone to postoperative recur. Therefore for osteosarcoma, invasion and transfer mechanism and related factors' interaction remains to be a key research subject.

AIM

We aim to find biological molecules marker can be used for osteosarcoma diagnosis through contrast of osteosarcoma sample and normal tissue samples.

MATERIALS AND METHODS

This analysis using human osteosarcoma expression profile data and three lesions normal tissue samples (liver, kidneys, lymph) expression data and compare them, and find significant specifically expressed genes, according to their function.

RESULTS

Research shows that the cancer cell proliferation, invasion, transfer and recurrent process involve many factors interaction, of which angiogenesis is the necessary condition of tumor growth, transfer and the recurrence.

CONCLUSIONS

Now the most important positive regulatory factor of angiogenesis is VEGF (vascular endothelial growth factor) and bFGF (basic fibroblast growth factor). Both of them are with a wide variety and close relationship of tumor angiogenesis and progress.

Pyruvate kinase M2 is highly correlated with the differentiation and the prognosis of esophageal squamous cell cancer

It's frequently stated that the pyruvate kinase M2 (PKM2) and Warburg effect are important for cancer development by accumulating more raw materials for macromolecule biosynthesis. However, the correlation between PKM2 and cancer is poorly reported. Here, we investigated the PKM2 expression in esophageal squamous cell cancer (ESCC). We observed that the expression of PKM2 was much higher in ESCC than in control normal tissue, and it is highly associated with many clinical features and prognosis. Specially, we found that the expression of PKM2 was closely related to the differentiation state of ESCC, and we further confirmed this discovery in vitro. As a result, out data indicated that PKM2 might be a useful indicator for determining the survival of patients with ESCC. Considering previous researches on the link among PKM2, Warburg effect, and differentiation, our study inferred the direct roles of PKM2 and Warburg effect in the differentiation of cancer cells rather than only providing synthetic intermediates for the promotion of cancer's progression.

Administrative data based patient safety research: a critical review

Administrative data are readily available, inexpensive, computer readable, and cover large populations. Despite coding irregularities and limited clinical details, administrative data supplemented by tools such as the Agency for Healthcare Research and Quality (AHRQ) patient safety indicators (PSIs) could serve as a screen for potential patient safety problems that merit further investigation, offer valuable insights into adverse impacts and risks of medical errors and, to some extent, provide benchmarks for tracking progress in patient safety efforts at local, state, or national levels.

Potentially inappropriate medication use in the community-dwelling elderly: findings from the 1996 Medical Expenditure Panel Survey

CONTEXT

Inappropriate medication use is a major patient safety concern, especially for the elderly population. Using explicit criteria, prior studies have found that 23.5% and 17.5% of the US community-dwelling elderly population used at least 1 of 20 potentially inappropriate medications in 1987 and 1992, respectively.

OBJECTIVES

To determine the prevalence of potentially inappropriate medication use in community-dwelling elderly persons in 1996, to assess trends over 10 years, categorize inappropriate medication use according to explicit criteria, and to examine risk factors for inappropriate medication use.

DESIGN, SETTING, AND PARTICIPANTS

Respondents aged 65 years or older (n = 2455) to the 1996 Medical Expenditure Panel Survey, a nationally representative survey of the US noninstitutionalized population were included. A 7-member expert panel was convened to categorize inappropriate medications.

MAIN OUTCOME MEASURE

Prevalence of use of 33 potentially inappropriate medications.

RESULTS

In 1996, 21.3% (95% confidence interval [CI], 19.5%-23.1%) of community-dwelling elderly patients in the United States received at least 1 of 33 potentially inappropriate medications. Using the expert panel's classifications, about 2.6% of elderly patients (95% CI, 2.0%-3.2%) used at least 1 of the 11 medications that should always be avoided by elderly patients; 9.1% (95% CI, 7.9%-10.3%) used at least 1 of the 8 that would rarely be appropriate; and 13.3% (95% CI, 11.7%-14.9%) used at least 1 of the 14 medications that have some indications but are often misused. Use of some inappropriate medications declined between 1987 and 1996. Persons with poor health and more prescriptions had a significantly higher risk of inappropriate medication use.

CONCLUSIONS

Overall inappropriate medication use in elderly patients remains a serious problem. Despite challenges in using explicit criteria for assessing inappropriate medications for elderly patients, such criteria can be applied to population-based surveys to identify opportunities to improve quality of care and patient safety. Enhancements of existing data sources to include dosage, duration, and indication may augment national improvement and monitoring efforts.

Patient Safety Indicators: using administrative data to identify potential patient safety concerns

OBJECTIVE

To develop Patient Safety Indicators (PSI) to identify potential in-hospital patient safety problems for the purpose of quality improvement.

DATA SOURCE/STUDY DESIGN

The data source was 2,400,000 discharge records in the 1997 New York State Inpatient Database. PSI algorithms were developed using systematic literature reviews of indicators and hand searches of the ICD-9-CM code book. The prevalence of PSI events and associations between PSI events and patient-level and hospital-level characteristics, length of stay, in-hospital mortality, and hospital charges were examined.

PRINCIPAL FINDINGS

PSIs were developed for 12 distinct clinical situations and an overall summary measure. The 1997 event rates per 10,000 discharges varied from 1.1 for foreign bodies left during procedure to 84.7 for birth traumas. Discharge records with PSI events had twofold to threefold longer hospital stays, twofold to 20-fold higher rates of in-hospital mortality, and twofold to eightfold higher total charges than records without PSI events. Multivariate logistic regression revealed that PSI events were primarily associated with increasing age (p < .001), hospitals performing more inpatient surgery (p < .001), and hospitals with higher percentage of beds in intensive care units (p < .001).

CONCLUSIONS

The PSIs provide an efficient and user-friendly tool to identify potential inhospital patient safety problems for targeted institution-level quality improvement efforts. Until better error-reporting systems are developed the PSIs can serve to shed light on the problem of medical errors not limited solely to mortality because of errors.

Induction of antibodies against GM2 ganglioside by immunizing melanoma patients using GM2-keyhole limpet hemocyanin + QS21 vaccine: a dose-response study

In a previous randomized Phase III trial (P. O. Livingston et al, J. Clin. Oncol., 12: 1036-1044, 1994), we demonstrated that immunization with GM2 and bacille Calmette-Guerin reduced the risk of relapse in stage III melanoma patients who were free of disease after surgical resection and who had no preexisting anti-GM2 antibodies. That vaccine formulation induced IgM anti-GM2 antibodies in 74% but induced IgG anti-GM2 antibodies in only 10% of the patients. To optimize the immune response against GM2, a reformulated vaccine was produced conjugating GM2 to keyhole limpet hemocyanin (KLH) and using the adjuvant QS21 (GM2-KLH/QS21). In pilot studies, 70 microg of vaccine induced IgG anti-GM2 antibodies in 76% of the patients. We wished to define the lowest vaccine dose that induced consistent, high-titer IgM and IgG antibodies against GM2. Fifty-two melanoma patients who were free of disease after resection but at high risk for relapse were immunized with GM2-KLH/QS21 vaccine at GM2 doses of 1, 3, 10, 30, or 70 ILg on weeks 1, 2, 3, 4, 12, 24, and 36. Serum collected at frequent and defined intervals was tested for anti-GM2 antibodies. Overall, 88% of the patients developed IgM anti-GM2 antibodies; 71% also developed IgG anti-GM2 antibodies. GM2-KLH doses of 3-70 microg seemed to be equivalent in terms of peak titers and induction of anti-GM2 antibodies. At the 30-microg dose level, 50% of the patients developed complement fixing anti-GM2 antibodies detectable at a serum dilution of 1:10. We conclude that the GM2-KLH/QS21 formulation is more immunogenic than our previous formulation and that 3 microg is the lowest dose that induces consistent, high-titer IgM and IgG antibodies against GM2.

Economic assessment of the community-acquired pneumonia intervention trial employing levofloxacin

OBJECTIVE

The purpose of this study was to assess use of a critical pathway designed to manage community-acquired pneumonia more efficiently than its management with conventional therapy.

METHODS

Economic outcomes were assessed in conjunction with a cluster-design, randomized, controlled trial. Nineteen participating Canadian hospitals were randomized to implement the critical pathway (n = 9) or conventional therapy (n = 10). The critical pathway included a clinical prediction rule to guide the admission decision, treatment with levofloxacin, and practice guidelines. Patient data on medical resource use, lost productivity, and quality of life were collected prospectively for > or =6 weeks after treatment. Costs were calculated from the government, health care system, and societal perspectives, with imputation of missing outpatient costs and the costs of lost productivity when necessary. Bootstrapping was used to identify 95% CIs for the total cost per patient.

RESULTS

The analysis included all eligible patients in the critical pathway (n = 716) and conventional therapy (n = 1027) arms. There were fewer hospital admissions in the critical pathway arm than in the conventional therapy arm, both overall (46.5% vs 62.2%; P = 0.01) and in low-risk patients (33.2% vs 46.8%; P < 0.001). Compared with conventional therapy, hospitals in the critical pathway arm had 1.6 fewer bed days per patient managed (P = 0.05) and used fewer inpatient medical resources. The 2 study arms had similar outpatient, readmission, and lost-productivity costs, and similar quality-of-life outcomes. The critical pathway produced cost savings from all 3 perspectives that ranged from $457 to $994 per patient.

CONCLUSIONS

The critical pathway employing levofloxacin resulted in cost savings compared with conventional therapy and did not compromise health outcomes.

[Study on the psychological status of video display terminal operator]

Occupational psychological test designed by the Labour Hygiene Department of West China University of Medical Sciences was applied to survey the mental health of 516 video display terminal (VDT) workers and 396 control workers in Chengdu. The results showed that mental health level of VDT workers was higher than that of controls. In the somatic disorder, anxious and hostile are increased obviously. With the prolonging of operating hours per week, somatic disorders, depression and obsession are increased, especially when VDT operating time is more than 30 hours per week and operating on VDT is more than ten years. This indicates that the operating hours should not be more than 30 hours per week. It is found by multiple factors analysis of data that the main adverse effects on mental health are age and VDT operating time.

[Study on the relationship between occupational factors and work ability of middle aged workers]

Based on the assessment of work ability index (WAI) of middle aged workers, associations between occupational factors and work ability decline of middle aged workers were examined in a case-control study. 1037 workers (age ranged from 40 to 60) were included in the study. The study group comprised 180 workers of mean age 47.71 years representing those who's work ability decreased. The control group comprised 857 workers of mean age 47.22 years representing those who's work ability was on a normal level. Results showed that some common occupation hazards such as dusts, noise, vibration, humidity, and high temperature were more frequently occurred in work environment of the study group than that of the control group. High risks were found in workers with these hazards. Another significant risk factor of work ability decline was heavy physical load. Significantly elevated risks were observed for physical load perception(OR = 2.52), repetitive work (OR = 1.36), poor work postures(OR = 1.48), and carrying heavy loads(OR = 1.59). As compared to physical loads, mental loads were not in relation to work ability decline. The information about occupational factors affecting work ability will be helpful for redesiging the work for the middle aged workers.

[Experimental study on the effect of abstinence with herbal preparation qingjunyin]

The effect of herbal preparation Qingjunyin (QJY) on the animal model of drug dependence was studied. After the morphinistic models of white rats and mice were made by ever increasing doses of morphine each time, the animals were divided into large dosage QJY group, small dosage QJY group, sustained morphine group and control group. The withdrawal symptoms were observed after naloxone was given to the animals intraperitoneally. The results showed that QJY groups withdrawal symptoms of the addicted white rats were alleviated, the number of jumps of the addicted mice was reduced, the scores of the principal symptoms of the animals were decreased, while the body weights of the animals were gained, comparing with the control group, the difference was significant (P < 0.01). The effects of QJY enhanced in the large dosage group, which suggests QJY has abstinence effects.

[Effect of different Anti-G suits on lower limb blood flow]

To study effects of different Anti-G suits (AGS) and different inflation pressure on human cardiac system, changes in lower limb arterial blood flow (BF), heart rate and blood pressure in 5 male subjects with three bladder coverage AGS and a capstain AGS were observed and recorded until inflation pressure reached to its maximum. The percent of bladder coverage was about 30%, 65% and 90% of lower body for three bladder AGS. All AGS were inflated to maximum pressure in +1Gz seating position. The results showed that calf BF, could be blocked by bladder AGS, and the relationship between the mean pressure for BF block and the percentage of bladder coverage was y = 29.66 - 16.35x. (P < 0.0001, r = -0.9229). While the thigh and calf BF was not blocked in subjects with the capsule AGS. The results indicate that the effect of "the higher bladder coverage AGS + lower IP" is probably equal to that of "the lower bladder coverage AGS + higher IP" in holding calf BF.

[Clinial study of "qingjunyin" detoxification for the treatment of heroin addicts]

To evaluate the efficacy of treatment of heroin addicts (n = 100) by "Qingjunyin" (QJY) detoxification (10 days program). Methadone detoxification (10 days program) group (n = 50) and colonidine treated group (n = 50) serve as controls. QJY group is given 180 ml P. O daily. The dosage of the two comparatine groups is given according to Documentation, the method of abserving the treatment protocols and detoxification standard is according to current regulation. The scores of abstinence syndrome in QJY detoxification group are lower than those in colonidine treated group in the first three days of potocol, but this difference disappear in the late stage of treatment. While QJY detoxification is effective as methadone detoxification in the control of abstinece syndrome during the first five days of treatment but the difference in the scores of abstinence syndrome between QJY and methadone group is observed during the late five days of protocol. QJY does not result in potential dependence and has definite curative effect in the treatment of heroin addiction.

[Changes of superoxide dismutase and lipid peroxide in lung tissue of rats after intratracheal injection of crocidolite and benzo(a) pyrene]

Wistar rats were divided into 4 groups: control group, Cro group, B(a) p group and Cro plus B(a) p group. Samples of lung tissue were collected 90, 180, 270, 360 and 540 days after the third time of intratracheal. The superoxide dismutase (SOD) activity, the level of lipid peroxide (LPO) and the ratio of SOD/LPO were observed. The results indicated that there was a synergistic action of Cro. and B(a) p.

Crystallization and preliminary X-ray diffraction studies of recombinant staphylokinase

Staphylokinase, a fibrin-specific plasminogen activator, was highly expressed in Escherichia coli and purified by ion-exchange and gel-filtration chromatography. The purified recombinant staphylokinase was fully active and readily crystallized against 1.2 M sodium citrate in 100 mM Tris-HCl buffer at pH 8.0 using the hanging-drop method. Crystals of staphylokinase diffract to better than 2.2 A resolution. The crystal belongs to the tetragonal space group P4(1)2(1)2 or its enantiomorph with unit-cell parameters a = b = 67.5, c = 150.1 A. There are two molecules in the asymmetric unit. In this paper, we described the first crystallization of a kind of plasminogen activator and present the results of preliminary X-ray diffraction data from the native protein.

The effects of hospital-physician integration strategies on hospital financial performance

STUDY QUESTION

This study investigated the longitudinal relations between hospital financial performance outcomes and three hospital-physician integration strategies: physician involvement in hospital governance, hospital ownership by physicians, and the integration of hospital-physician financial relationships.

DATA SOURCES AND STUDY SETTING

Using secondary data from the State of California, integration strategies in approximately 300 California short-term acute care hospitals were tracked over a ten-year period (1981-1990).

STUDY DESIGN

The study used an archival design. Hospital performance was measured on three dimensions: operational profitability, occupancy, and costs. Thirteen control variables were used in the analyses: market competition, affluence, and rurality; hospital ownership; teaching costs and intensity; multihospital system membership; hospital size; outpatient service mix; patient volume case mix; Medicare and Medicaid intensity; and managed care intensity.

DATA COLLECTION/EXTRACTION

Financial and utilization data were obtained from the State of California, which requires annual hospital reports. A series of longitudinal regressions tested the hypotheses.

PRINCIPAL FINDINGS

Considerable variation was found in the popularity of the three strategies and their ability to predict hospital performance outcomes. Physician involvement in hospital governance increased modestly from 1981-1990, while ownership and financial integration declined significantly. Physician governance was associated with greater occupancy and higher operating margins, while financial integration was related to lower hospital operating costs. Direct physician ownership, particularly in small hospitals, was associated with lower operating margins and higher costs. Subsample analyses indicate that implementation of the Medicare prospective payment system in 1983 had a major impact on these relationships, especially on the benefits of financial integration.

CONCLUSIONS

The findings support the validity of hospital-physician financial integration efforts, and to a lesser extent the involvement of physicians in hospital governance. The results lend considerably less support for strategies built around direct physician ownership in hospitals, particularly since PPS implementation.

RELEVANCE/IMPACT

These findings challenge prior studies that found few financial benefits to hospital-physician integration prior to PPS implementation in 1983. The results imply that financial benefits of integration may take several years after implementation to emerge, are most salient in a managed care or managed competition environment, and vary by hospital size and multihospital system membership.