Effect of heavy metal stress on antioxidative enzymes and lipid peroxidation in leaves and roots of two mangrove plant seedlings (Kandelia candel and Bruguiera gymnorrhiza)

The effects of multiple heavy metal stress on the activity of antioxidative enzymes and lipid peroxidation were studied in leaves and roots of two mangrove plants, Kandelia candel and Bruguiera gymnorrhiza, grown under control (10 per thousand NaCl nutrient solution) or five levels of multiple heavy metal stress (10 per thousand NaCl nutrient solution containing different concentration of Pb2+, Cd2+, and Hg2+). Leaves and roots of control and heavy metal-stressed plants were harvested after two months. In leaves of heavy metal-stressed plants superoxide dismutase (SOD) and peroxidase (POD) activities fluctuated in different stress levels compared to the control, while catalase (CAT) activity increased with stress levels in K. candel, but remained unchanged in leaves of B. gymnorrhiza. In comparison with the control, the dynamic tendency of SOD, CAT, and POD activities in roots of heavy metal-stressed plants all ascended, and then declined. The increase in enzyme activities demonstrated that K. candel is more tolerant to heavy metals than B. gymnorrhiza. Lipid peroxidation was enhanced only in leaves of heavy metal-stressed B. gymnorrhiza. These results indicate that in heavy-metal stress antioxidative activities may play an important role in K. candel and B. gymnorrhiza and that cell membrane in leaves and roots of K. candel have greater stability than those of B. gymnorrhiza. For pollution monitoring purposes, POD activity in roots and leaves maybe serve as a biomarker of heavy metal stress in K. candel, while lipid peroxidation maybe serve as biomarker in B. gymnorrhiza.

Anterior-posterior and rotational displacement of the tibia elicited by quadriceps contraction

The anterior-posterior displacement and rotation of the tibia elicited by isolated loading of the quadriceps muscle was determined as a function of joint angle and muscle load using a computerized radiographic technique. Data collected from 12 fresh-frozen cadaveric knees demonstrated that quadriceps contraction can result in significant (less than 7 mm) anterior displacement of the tibia in the range of 0 degrees to 80 degrees of flexion, and a mild (less than 2 mm) posterior displacement in the range of 80 degrees to 120 degrees of flexion. Peak anterior displacement of 6.3 mm was observed at 30 degrees of flexion under a 12 kg load in the quadriceps, while a constant 1.5 mm posterior displacement was observed throughout flexion angles exceeding 80 degrees. It was further shown that the magnitude of the anterior displacement increased nonlinearly as the quadriceps force increased. Loading of the quadriceps also resulted in internal rotation of the tibia in the range of 0 degrees to 90 degrees of flexion, and in external rotation of the tibia in the range of 90 degrees to 120 degrees. Peak internal rotation of 7 degrees was observed at 15 degrees of flexion and a peak external rotation of 1 degrees was detected at 120 degrees of flexion. Larger quadriceps load resulted in larger rotation. We concluded that quadriceps contraction during knee extension has direct impact on anterior displacement and rotation of the tibia and therefore on anterior cruciate ligament stress, increasing it as the muscle's force is increased during knee extension.(ABSTRACT TRUNCATED AT 250 WORDS)

Tree-structured prediction for censored survival data and the Cox model

Prediction trees for the analysis of survival data are discussed. It is shown that trees are useful not only in summarizing the prognostic information contained in a set of covariates (prognostic classification), but also in detecting and displaying treatment-covariates interactions (subgroup analysis). The RECPAM approach to tree-growing is outlined; prognostic classification and subgroup analysis are then formulated within the RECPAM framework and on the basis of the Cox proportional hazards models with a priori strata. Two examples of data analysis are presented. The issue of cross-validation is discussed in relation to computationally cheaper model selection criteria.

A computer simulation of the non-Newtonian blood flow at the aortic bifurcation

A two-dimensional numerical model was developed to determine the effect of the non-Newtonian behavior of blood on a pulsatile flow at the aortic bifurcation. The blood rheology was described by a weak-form Casson equation. The successive-over-relaxation (SOR) method was used to solve both the vorticity and Poisson equations numerically. It was disclosed that the non-Newtonian property of blood did not drastically change the flow patterns, but caused an appreciable increase in the shear stresses and a slightly higher resistance to both flow separations and the phase shifts between flow layers.

The interactions of paclitaxel with tumour microenvironment

Today, it is well-known that the interactions and secretion within the tumour are crucial to consider for cancer therapy. Some novel cancer therapy modalities such as immunotherapy or tumour vaccination therapy work based on the control of interactions within the tumour microenvironment (TME). It has been revealed that anti-cancer drugs or radiotherapy can modulate some interactions in favour of cancer therapy. However, they may induce some mechanisms to increase the resistance of cancer cells to therapy. Paclitaxel is known as the first approved herbal derived chemotherapy drug. Although the main known anti-cancer effect of paclitaxel is the inhibition of the cell cycle, today, it has been well known that paclitaxel may suppress the tumour via modulating several interactions in TME. Furthermore, paclitaxel may increase the expression of some tumour resistance drivers. This review aims to discuss the interactions within TME following treatment with paclitaxel. The effects of paclitaxel on the anti-tumour immunity, immunosuppressive cells, hypoxia, and also angiogenesis will be discussed. The targeting of these interactions may be interesting to increase therapy efficiency using the combination modalities.

A role for a RhoA/ROCK/LIM-kinase pathway in the regulation of cytotoxic lymphocytes

Polarization of lipid rafts and granules to the site of target contact is required for the development of cell-mediated killing by cytotoxic lymphocytes. We have previously shown that these events require the activation of proximal protein tyrosine kinases. However, the downstream intracellular signaling molecules involved in the development of cell-mediated cytotoxicity remain poorly defined. We report here that a RhoA/ROCK/LIM-kinase axis couples the receptor-initiated protein tyrosine kinase activation to the reorganization of the actin cytoskeleton required for the polarization of lipid rafts and the subsequent generation of cell-mediated cytotoxicity. Pharmacologic and genetic interruption of any element of this RhoA/ROCK/LIM-kinase pathway inhibits both the accumulation of F-actin and lipid raft polarization to the site of target contact and the subsequent delivery of the lethal hit. These data define a specialized role for a RhoA-->ROCK-->LIM-kinase pathway in cytotoxic lymphocyte activation.

Effects of eating space and availability of water in feeders on productivity and eating behavior of grower/finisher pigs

Three experiments were conducted to determine the effects of eating space and availability of water within feeders on the productivity and behavior of growing/finishing pigs. In Exp. 1, 12 commercial feeders were classified as being either single-space (SS) or multiple-space (MS), and either as dry (D) or wet/dry (WD), resulting in two SS-D, four MS-D, three SS-WD and three MS-WD models. Each model was evaluated using four pens of 12 pigs, which were fed a mash diet throughout the growing/finishing period (25 to 106 kg). Pigs were videotaped when they were approximately 40 and 80 kg in weight to determine eating behavior. The number of feeding spaces did not affect the productivity of the pigs, but the presence of water within the feeder resulted in increases in ADFI (P < .05) and ADG (P < .05) and a reduction in carcass lean (P < .05). Pigs eating from SS feeders spent 15% less time eating than those fed from two-space feeders (P < .05), and occupancy rate for feeding spaces was increased by 75% (P < .05). The WD feeders also resulted in a reduction (17%) in eatingtime compared to D models (P < .01), and occupancy rate for WD feeders was similarly reduced (P < .05). Pigs spent 16% less time eating when they weighed approximately 80 kg than when they weighed 40 kg (P < .01). In Exp. 2, rate of eating was determined during a short test on the same 12 feeder models for both small (48 kg) and large (90 kg) pigs. Large pigs ate faster than small pigs, but eating rate was not affected by feeding space or presence of water in the feeder. In Exp. 3, eating rate was determined for small amounts of dry or wet feed. Premixing water with the feed (1:1 ratio by weight) increased eating speed (P < .01). We concluded that 12 pigs can be fed from a single-space feeder without affecting productivity. The inclusion of water within a feeder decreases time spent eating, but it increases ADFI and ADG. When pigs are small, they spend more time eating, and feeder occupancy rates are higher than when they are large.

Errors in the estimation of arterial wall shear rates that result from curve fitting of velocity profiles

An analysis was performed to determine the error that results from the estimation of the wall shear rates based on linear and quadratic curve-fittings of the measured velocity profiles. For steady, fully developed flow in a straight vessel, the error for the linear method is linearly related to the distance between the probe and the wall, dr1, and the error for the quadratic method is zero. With pulsatile flow, especially a physiological pulsatile flow in a large artery, the thickness of the velocity boundary layer, delta is small, and the error in the estimation of wall shear based on curve fitting is much higher than that with steady flow. In addition, there is a phase lag between the actual shear rate and the measured one. In oscillatory flow, the error increases with the distance ratio dr1/delta and, for a quadratic method, also with the distance ratio dr2/dr1, where dr2 is the distance of the second probe from the wall. The quadratic method has a distinct advantage in accuracy over the linear method when dr1/delta << 1, i.e. when the first velocity point is well within the boundary layer. The use of this analysis in arterial flow involves many simplifications, including Newtonian fluid, rigid walls, and the linear summation of the harmonic components, and can provide more qualitative than quantitative guidance.

[Several suggestion of operation for colorectal cancer under the outbreak of Corona Virus Disease 19 in China]

Pneumonia caused by SARS-Cov-2 infection has been reported in Wuhan since December 2019, and spread rapidly across the country. The radical operation of colorectal cancer is confine operation. Patients with colorectal cancer should receive operation as soon as possible after elective operation is resumed in each hospital. SARS-Cov-2 virus can be transmitted by asymptomatic infectors, and it has been confirmed to be transmitted by droplets and contact. However, fecal-oral transmission and aerosol transmission have not been excluded. Based onLaparoscopic colorectal operation experiences, the author suggests that the surgery strategy for colorectal cancer patients under the COVID-19 situation. Recommending laparoscopy-assisted radical surgery for colorectal cancer patients. The aerosols need to be strictly managed during operation. NOSES and TaTME should be carried out with cautious during the epidemic period. Protective stoma should be carried out scientifically and reasonably, and the protection of operating room personnel should be strengthened.

Immortalization of epithelial progenitor cells mediated by resveratrol

Within the hierarchy of epithelial stem cells, normal progenitor cells may express regulated telomerase during renewal cycles of proliferation and differentiation. Discontinuous telomerase activity may promote increased renewal capacity of progenitor cells, while deregulated/continuous telomerase activity may promote immortalization when differentiation and/or senescent pathways are compromised. In the present work, we show that resveratrol activates, while progesterone inactivates, continuous telomerase activity within 24 h in subpopulations of human Li-Fraumeni syndrome-derived breast epithelial cells. Resveratrol results in immortalization of mixed progenitor cells with mutant p53, but not human epithelial cells with wild type p53. Our results demonstrate the potential for renewing progenitor cells with mutant p53 to immortalize after continuous telomerase expression when exposed to certain environmental compounds. Understanding the effects of telomerase modulators on endogenous telomerase activity in progenitor cells is relevant to the role of immortalization in the initiation and progression of cancer subtypes.

Properties of excitatory amino acid transport in the human U373 astrocytoma cell line

In this study, we describe the presence of Na(+)-dependent high-affinity L-glutamate transport activity in the human U373 astrocytoma cell line. U373 cells exhibited a robust accumulation of L-glutamate which was predominantly (85%) extracellular Na(+)-dependent. Kinetic analysis of this transport activity revealed that the uptake followed first-order Michaelis-Menten kinetics and was high-affinity in nature. The kinetic parameters estimated by Eadie-Hofstee transformation of the saturable uptake were 37.3 +/- 5.1 microM for K(m) and 0.13 +/- 0.02 nmol min-1 mg-1 protein for Vmax. A total of 14 known inhibitors of high-affinity L-glutamate transport were examined for their abilities to inhibit L-glutamate uptake by U373 cells. Three compounds, kainate (KA), dihydrokainate (DHK) and alpha-aminoadipic acid produced less than 30% inhibition at 1 mM. The lack of effect of both KA and DHK indicates that the predominant astroglial L-glutamate transporter EAAT2 (excitatory amino acid transporter 2) does not contribute to the uptake activity present in these cells. The rank order of inhibitory potency for the remaining 11 compounds tested was L-cysteine sulphinate = L-CCG-III = L-cysteate = L-aspartate = threo-beta-hydroxyaspartate > trans-PDC > D-aspartate = MPDC > beta-glutamate > L-CCG-IV = L-aspartate-beta-hydroxamate. Pre-treatment of U373 cells with phorbol ester for 30 min resulted in a 56% decrease in L-glutamate uptake and this effect was blocked in a concentration-dependent manner by the PKC inhibitor bisindolylmaleimide I. Expression of L-glutamate transporters by U373 cells was examined by reverse transcriptase polymerase chain reaction (RT-PCR) and Western analysis. Transcripts for both the EAAT1 and EAAT3 transporter subtypes were detected but not for EAATs 2, 4, and 5. Immunoblot analysis confirmed the presence of EAAT3 protein, however, we were unable to detect EAAT1 protein. In conclusion, the Na(+)-dependent high-affinity L-glutamate transport into human U373 astrocytoma cells appears to be mediated predominantly by the EAAT3 subtype.

The effect of ofloxacin otic drops on the regeneration of human traumatic tympanic membrane perforations

OBJECTIVE

To investigate the effects of direct application of ofloxacin otic drops on human traumatic tympanic membrane perforations (TMPs).

STUDY DESIGN

Prospective, sequential allocation, controlled clinical study.

SETTING

Tertiary university hospital.

PARTICIPANTS

In total, 149 patients with traumatic TMPs were recruited. They were allocated sequentially to two groups: a conservative observation group (n = 75) and a ofloxacin drops-treated group (n = 74).

MAIN OUTCOME MEASURES

The closure rate, closure time and rate of otorrhoea were compared between the groups at 6 months.

RESULTS

In total, 145 patients were analysed. The closure rates of medium perforations between the groups were not significantly different (P = 0.35); however, the ofloxacin drops-treated group had a significantly shorter closure time for medium perforations than the observation group (P < 0.01). Additionally, the ofloxacin drops-treated group showed improvement in the closure rate of large perforations (P = 0.02) and a significantly shorter mean closure time (P < 0.01) than the observation group. However, purulent otorrhoea was not significantly different between the groups (P = 0.37).

CONCLUSIONS

The present findings indicate that the moist eardrum environment resulting from topical application of ofloxacin drops shortened the closure time and improved the closure rate, but did not affect hearing improvement or increase the rate of middle ear infection of large traumatic TMPs. Thus, although traumatic TMPs tend to heal spontaneously, moist therapy can be considered for traumatic, large TMPs in the clinic.

Effect of micelle fatty acid composition and 3,4,3', 4'-tetrachlorobiphenyl (TCB) exposure on intestinal [(14)C]-TCB bioavailability and biotransformation in channel catfish in situ preparations

Polychlorinated biphenyls are transferred in the diet along aquatic food chains. This study investigated the effect of dietary micelle composition and 3,4,3',4'-tetrachlorobiphenyl (TCB) exposure upon the subsequent systemic bioavailability and intestinal metabolism of [(14)C]-TCB in a catfish in situ intestinal preparation. Initial in vitro experiments examined the solubility of [(14)C]-TCB in micelles of varying fatty acid composition. Micelles composed of single fatty acids demonstrated greater [(14)C]-TCB solubility with those fatty acids of longer chain length. Similarly, micelles of the long-chain fatty acid, linoleic acid, solubilized more [(14)C]-TCB than mixed micelles formulated from equal amounts of myristic (14:0), palmitic (16:0), stearic (18:0), or linoleic (18:2) acids. Systemic bioavailability of [(14)C]-TCB (60 microM) from an in situ perfused intestinal preparation was 2.2-fold greater when delivered to the intestine in linoleic acid micelles as compared to the mixed micelle preparation. Catfish exposed in vivo to either 0.5 or 5.0 mg TCB/kg feed for 10 days resulted in a 45 to 47% decrease in the subsequent systemic bioavailability of [(14)C]-TCB in the in situ intestinal preparation. Total intestinal cytochrome P450 content was not significantly affected by TCB preexposure. Immunodetectable CYP1A was found only in the 5.0 mg TCB/kg diet treatment. Corresponding intestinal aryl hydrocarbon hydroxylase (AHH) activities were 2.46 +/- 1.16, 2.43 +/- 1.58, and 11.35 +/- 10.25 pmol/min/mg protein for the control, 0.5, and 5 mg TCB/kg diet groups, respectively. [(14)C]-TCB in the in situ preparation was metabolized to only a small degree upon a single pass through the intestinal mucosa of the catfish. High variability and low rates of metabolism precluded the association of the magnitude of metabolism with dietary TCB pretreatment. Analysis of tissue sample extracts demonstrated 4 minor peaks, 3 of which were tentatively identified by co-elution with standards as 2-OH-3,4,3',4'-TCB, 4-OH-3,5,3',4'-TCB, and 5-OH-3, 4,3',4'-TCB. A fourth remains unidentified. Histological changes in the intestine such as thinning of the submucosa and increased numbers of goblet cells were evident at the 5.0 mg TCB/kg diet dose. These results suggest that TCB intestinal bioavailability may be linked to micelle composition as well as TCB exposure history. Furthermore, single pass intestinal metabolism appears to be a minor contributor to the biotransformational modification of dietary TCB.

Ecological environment changes in Daya Bay, China, from 1982 to 2004

Data collected from 12 marine monitoring stations in Daya Bay from 1982 to 2004 reveal a substantial change in the ecological environment of this region. The average N/P ratio increased from 1.377 in 1985 to 49.09 in 2004. Algal species changed from 159 species of 46 genera in 1982 to 126 species of 44 genera in 2004. Major zooplankton species went from 46 species in 1983 to 36 species in 2004. The annual mean biomass of benthic animals was recorded at 123.10 g m(-2) in 1982 and 126.68 g m(-2) in 2004. Mean biomass and species of benthic animals near nuclear power plants ranged from 317.9 g m(-2) in 1991 to 45.24 g m(-2) in 2004 and from 250 species in 1991 to 177 species in 2004. A total of 12-19 species of hermatypic corals and 13 species of mangrove plants were observed in Daya Bay from 1984 to 2002.

An ellipsoid farrowing crate: its ergonomical design and effects on pig productivity

An ellipsoid farrowing crate was designed and compared to the conventional rectangular crate with regard to its effect on sows' production traits. The main features of this crate are its oval horizontal frame and bowed vertical bars. Thirty-two sows farrowed in each system. Those in the ellipsoid crates raised 318 pigs and those in the rectangular crates raised 304. Stillbirth rate was lower in the ellipsoid crates than in the rectangular crates (P < .05). Among pigs born live, no significant difference due to crate was found on the deaths by crushing, infection, and other causes. The overall pigs' weaning rate from total births was also similar in both crates (P > .05). The daily weight gains of pigs for the 1st wk in the ellipsoid crate did not differ from those of pigs in the rectangular crates (P > .05) but were higher for the period from d 7 to d 21 (P < .05). The ellipsoid crate allowed the sow to turn around and have more freedom to move. However, the increase in sow movement did not cause a higher pig crushing rate than that in the traditional crate (P > .05). Behavioral observations also showed that the ellipsoid farrowing crate permitted easier visual and tactile contact of dams with their pigs and offered pigs better access to the sow's teats.

A computer simulation of the blood flow at the aortic bifurcation with flexible walls

To understand the role of fluid dynamics in atherogenesis, especially the effect of the flexibility of arteries, a two-dimensional numerical model for blood flow at the aortic bifurcation with linear viscoelastic walls is developed. The arbitrary Lagrangian-Eulerian method is adopted to deal with the moving boundary problem. The wall expansion induces flow reversals or eddies during the decelerating systole while the wall contraction restricts them during the diastole. A flexible bifurcation experiences the shear stresses about 10 percent lower than those of a rigid one.

Impact of basic fibroblast growth factor on healing of tympanic membrane perforations due to direct penetrating trauma: a prospective non-blinded/controlled study

OBJECTIVE

To investigate the effect of direct application of basic fibroblast growth factor (bFGF) on healing of tympanic membrane perforations due to direct traumatic penetration through the external auditory canal.

DESIGN

A prospective non-blinded controlled study.

SETTING

University-affiliated teaching hospital.

PARTICIPANTS

In total, 104 patients with small [<25%] penetrating perforations were recruited. They were alternatively allocated to two groups: Control (spontaneous healing, n = 51) and FGF treatment (direct application of bFGF drops in the clinic and repeated daily by the patient, n = 53).

OUTCOMES

Perforation closure rate and time and hearing gain were recorded and compared between the two groups. Information on earache, dizziness and facial paralysis was also collected.

RESULTS

In total, 93 (89%) patients were finally analysed. The closure rate at 3 m of the perforations in the control spontaneous healing and bFGF treatment groups were 77% and 100%, respectively; the difference was statistically significant (P = 0.01). The average closure time was 43.1 ± 2.5 days (range, 17-57 days) for control patients, which was significantly longer (P < 0.01) than that for the bFGF-treated patients (12.6 ± 1.2 days; range, 3-21 days). The mean hearing improvement at 3 m was not significantly different between the FGF treatment and control groups (1.7 ± 2.4 dB vs 11.5 ± 1.9 dB, P > 0.05). No significant difference was observed in earache, dizziness and facial paralysis between two groups.

CONCLUSIONS

Direct application of bFGF may offer an effective topical management of penetrating traumatic tympanic membrane perforations, particularly for small-sized perforations.

Long non‑coding RNA KCNQ1OT1 promotes nasopharyngeal carcinoma cell cisplatin resistance via the miR‑454/USP47 axis

Long non‑coding RNAs serve an essential role in drug resistance in various types of cancer, including lung, breast and bladder cancer. The present study aimed to investigate whether KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) was associated with cisplatin (DDP) resistance in nasopharyngeal carcinoma (NPC). KCNQ1OT1, microRNA (miR)‑454 and ubiquitin specific peptidase 47 (USP47) expression levels were measured via reverse transcription‑quantitative PCR. 5‑8F/DDP and SUNE‑1/DDP cell viability and chemosensitivity were assessed by performing Cell Counting Kit‑8 assays. Colony forming and Transwell assays were conducted to assess the effect of the KCNQ1OT1/miR‑454/USP47 axis on DDP resistance in NPC cells. The association between miR‑454 and KCNQ1OT1 or USP47 was verified via bioinformatics analysis, dual‑luciferase reporter assays and RIP assays. KCNQ1OT1 and USP47 expression levels were significantly upregulated, whereas miR‑454 expression levels were significantly downregulated in DDP‑resistant NPC cells compared with parental NPC cells. KCNQ1OT1 knockdown promoted chemosensitivity in DDP‑resistant NPC cells (5‑8F/DDP and SUNE‑1/DDP), as indicated by significantly decreased cell proliferation, migration and invasion in the short hairpin RNA (sh)KCNQ1OT1 group compared with the sh‑negative control (NC) group. Moreover, miR‑454 was identified as a target of KCNQ1OT1. KCNQ1OT1 overexpression significantly reversed miR‑454 overexpression‑mediated effects on NPC cell viability and DDP resistance. Furthermore, the results indicated that miR‑454 directly targeted USP47. Compared with the shNC group, USP47 knockdown significantly suppressed NPC cell viability and DDP resistance, which was significantly reversed by co‑transfection with miR‑454 inhibitor. Furthermore, compared with the shNC group, KCNQ1OT1 knockdown significantly downregulated USP47 expression, which was significantly counteracted by miR‑454 knockdown. Collectively, the results of the present study indicated that KCNQ1OT1 enhanced DDP resistance in NPC cells via the miR‑454/USP47 axis, suggesting a potential therapeutic target for patients with DDP‑resistant NPC.

Inducible expression and pharmacology of the human excitatory amino acid transporter 2 subtype of L-glutamate transporter

1. In this study we have examined the use of the ecdysone-inducible mammalian expression system (Invitrogen) for the regulation of expression of the predominant L-glutamate transporter EAAT2 (Excitatory Amino Acid Transporter) in HEK 293 cells. 2. HEK 293 cells which were stably transformed with the regulatory vector pVgRXR (EcR 293 cells) were used for transfection of the human EAAT2 cDNA using the inducible vector pIND and a clone designated HEK/EAAT2 was selected for further characterization. 3. Na+-dependent L-glutamate uptake activity (3.2 pmol min-1 mg-1) was observed in EcR 293 cells and this was increased approximately 2 fold in the uninduced HEK/EAAT2 cells, indicating a low level of basal EAAT2 activity in the absence of exogenous inducing agent. Exposure of HEK/EAAT2 cells to the ecdysone analogue Ponasterone A (10 microM for 24 h) resulted in a > or = 10 fold increase in the Na+-dependent activity. 4. L-glutamate uptake into induced HEK/EAAT2 cells followed first-order Michaelis-Menten kinetics and Eadie-Hofstee transformation of the saturable uptake data produced estimates of kinetic parameters as follows; Km 52.7+/-7.5 microM, Vmax 3.8+/-0.9 nmol min-1 mg-1 protein. 5. The pharmacological profile of the EAAT2 subtype was characterized using a series of L-glutamate transport inhibitors and the rank order of inhibitory potency was similar to that described previously for the rat homologue GLT-1 and in synaptosomal preparations from rat cortex. 6. Addition of the EAAT2 modulator arachidonic acid resulted in an enhancement (155+/-5% control in the presence of 30 microM) of the L-glutamate transport capacity in the induced HEK/EAAT2 cells. 7. This study demonstrates that the expression of EAAT2 can be regulated in a mammalian cell line using the ecdysone-inducible mammalian expression system.

Retrospective study of the functional and oncological outcomes of conformal sphincter preservation operation in the treatment of very low rectal cancer

BACKGROUND

Conformal sphincter preservation operation (CSPO) is a new surgical procedure for very low rectal cancers (within 4-5 cm from the anal verge). CSPO preserves more of the dentate line and distal rectal wall and also avoids injuring nerves in the intersphincteric space, resulting in satisfactory anal function after resection. The aim of this study was to analyze the short-term surgical results and long-term oncological and functional outcomes of CSPO.

METHODS

Consecutive patients with very low rectal cancer, who had CSPO between January 2011 and October 2018 at Changhai Hospital, Shanghai were included. Patient demographics, clinicopathological features, oncological outcomes and anal function were analyzed.

RESULTS

A total of 102 patients (67 men) with a mean age of 56.9 ± 10.8 years were included. The median distance of the tumor from the anal verge was 3 (IQR, 3-4) cm. Thirty-five patients received neoadjuvant chemoradiation (nCRT). The median distal resection margin (DRM) was 0.5 (IQR, 0.3-0.8) cm. One patient had a positive DRM. All circumferential margins were negative. There was no perioperative mortality. The postoperative complication rate was 19.6%. The median duration of follow-up was 28 (IQR, 12-45.5) months. The local recurrence rate was 2% and distant metastasis rate was 10.8%. The 3-year overall survival and disease-free survival rates were 100% and 83.9%, respectively. The mean Wexner incontinence and low anterior resection syndrome scores 12 months after ileostomy reversal were 5.9 ± 4.3, and 29.2 ± 6.9, respectively.

CONCLUSIONS

For patients with very low rectal cancers, fecal continence can be preserved with CSPO without compromising oncological results.

Predicting 30-day Hospital Readmission with Publicly Available Administrative Database. A Conditional Logistic Regression Modeling Approach

INTRODUCTION

This article is part of the Focus Theme of Methods of Information in Medicine on "Big Data and Analytics in Healthcare".

BACKGROUND

Hospital readmissions raise healthcare costs and cause significant distress to providers and patients. It is, therefore, of great interest to healthcare organizations to predict what patients are at risk to be readmitted to their hospitals. However, current logistic regression based risk prediction models have limited prediction power when applied to hospital administrative data. Meanwhile, although decision trees and random forests have been applied, they tend to be too complex to understand among the hospital practitioners.

OBJECTIVES

Explore the use of conditional logistic regression to increase the prediction accuracy.

METHODS

We analyzed an HCUP statewide inpatient discharge record dataset, which includes patient demographics, clinical and care utilization data from California. We extracted records of heart failure Medicare beneficiaries who had inpatient experience during an 11-month period. We corrected the data imbalance issue with under-sampling. In our study, we first applied standard logistic regression and decision tree to obtain influential variables and derive practically meaning decision rules. We then stratified the original data set accordingly and applied logistic regression on each data stratum. We further explored the effect of interacting variables in the logistic regression modeling. We conducted cross validation to assess the overall prediction performance of conditional logistic regression (CLR) and compared it with standard classification models.

RESULTS

The developed CLR models outperformed several standard classification models (e.g., straightforward logistic regression, stepwise logistic regression, random forest, support vector machine). For example, the best CLR model improved the classification accuracy by nearly 20% over the straightforward logistic regression model. Furthermore, the developed CLR models tend to achieve better sensitivity of more than 10% over the standard classification models, which can be translated to correct labeling of additional 400 - 500 readmissions for heart failure patients in the state of California over a year. Lastly, several key predictor identified from the HCUP data include the disposition location from discharge, the number of chronic conditions, and the number of acute procedures.

CONCLUSIONS

It would be beneficial to apply simple decision rules obtained from the decision tree in an ad-hoc manner to guide the cohort stratification. It could be potentially beneficial to explore the effect of pairwise interactions between influential predictors when building the logistic regression models for different data strata. Judicious use of the ad-hoc CLR models developed offers insights into future development of prediction models for hospital readmissions, which can lead to better intuition in identifying high-risk patients and developing effective post-discharge care strategies. Lastly, this paper is expected to raise the awareness of collecting data on additional markers and developing necessary database infrastructure for larger-scale exploratory studies on readmission risk prediction.

Surface conformations of an anti-ricin aptamer and its affinity for ricin determined by atomic force microscopy and surface plasmon resonance

We used atomic force microscopy (AFM) and surface plasmon resonance (SPR) to study the surface conformations of an anti-ricin aptamer and its specific binding affinity for ricin molecules. The effect of surface modification of the Au(111) substrate on the aptamer affinity was also estimated. The AFM topography images had a resolution high enough to distinguish different aptamer conformations. The specific binding site on the aptamer molecule was clearly located by the AFM recognition images. The aptamer on a Au(111) surface modified with carboxymethylated-dextran (CD) showed both similarities to and differences from the one without CD modification. The influence of CD modification was evaluated using AFM images of various aptamer conformations on the Au(111) surface. The affinity between ricin and the anti-ricin aptamer was estimated using the off-rate values measured using AFM and SPR. The SPR measurements of the ricin sample were conducted in the range from 83.3 pM to 8.33 nM, and the limit of detection was estimated as 25 pM (1.5 ng mL(-1)). The off-rate values of the ricin-aptamer interactions were estimated using both single-molecule dynamic force spectroscopy (DFS) and SPR as (7.3 ± 0.4) × 10(-4) s(-1) and (1.82 ± 0.067) × 10(-2) s(-1), respectively. The results show that single-molecule measurements can obtain different reaction parameters from bulk solution measurements. In AFM single-molecule measurements, the various conformations of the aptamer immobilized on the gold surface determined the availability of each specific binding site to the ricin molecules. The SPR bulk solution measurements averaged the signals from specific and non-specific interactions. AFM images and DFS measurements provide more specific information on the interactions of individual aptamer and ricin molecules.

The pharmacological profile of L-glutamate transport in human NT2 neurones is consistent with excitatory amino acid transporter 2

The human teratocarcinoma cell line NTera2/D1 can be differentiated to produce post-mitotic neurones (NT2-N cells) by prolonged (> 3 week) exposure to retinoic acid. In this study, we describe the characterisation of high-affinity Na+-dependent L-glutamate transport activity in post-mitotic differentiated NT2-N cells. NT2-N cells, but not the undifferentiated precursor cells, transported L-glutamate in a Na+-dependent manner, as determined by equimolar replacement of Na+ with choline. L-glutamate uptake was saturable and Eadie-Hofstee transformation of the saturation data revealed a Km of 10.6+/-0.8 microM, and a maximum transport capacity (Vmax) of 100.3+/-12.3 pmol min(-1) mg(-1) protein. Pharmacological characterisation of the transport activity in NT2-N cells produced a rank order of inhibitory activity which was identical to that determined for the human excitatory amino acid transporter 2 which we have analysed in a stable mammalian cell line (Madin Darby Canine Kidney (MDCK) cells). Of particular note, L-glutamate transport by NT2-N cells was sensitive to both dihydrokainate and kainate. The expression of human excitatory amino acid transporter mRNAs was studied using reverse transcriptase polymerase chain reaction. NT2-N cells expressed transcripts for excitatory amino acid transporters 2 and 3, but not for the subtypes 1, 4 and 5. We conclude that although the mRNA expression studies suggest the presence of transcripts for both excitatory amino acid transporter 2 and 3 in NT2-N cells, the sensitivity to dihydrokainate and kainate determined in the pharmacological analysis indicates that, of the known transporter subtypes, excitatory amino acid transporter 2 contributes to the bulk of the L-glutamate transport activity present in these cells.