In vitro drug screening models derived from different PC12 cell lines for exploring Parkinson's disease based on electrochemical signals of catecholamine neurotransmitters

Gold nanostructures and a Nafion modified screen-printed carbon electrode (Nafion/AuNS/SPCE) were developed to assess the cell viability of Parkinson's disease (PD) cell models. The electrochemical measurement of cell viability was reflected by catecholamine neurotransmitter (represented by dopamine) secretion capacity, followed by a traditional tetrazolium-based colorimetric assay for confirmation. Due to the  capacity to synthesize, store, and release catecholamines as well as their unlimited homogeneous proliferation, and ease of manipulation, pheochromocytoma (PC12) cells were used for PD cell modeling. Commercial low-differentiated and highly-differentiated PC12 cells, and home-made nerve growth factor (NGF) induced low-differentiated PC12 cells (NGF-differentiated PC12 cells) were included in the modeling. This approach achieved sensitive and rapid determination of cellular modeling and intervention states. Notably, among the three cell lines, NGF-differentiated PC12 cells displayed the enhanced neurotransmitter secretion level accompanied with attenuated growth rate, incremental dendrites in number and length that were highly resemble with neurons. Therefore, it was selected as the PD-tailorable modeling cell line. In short, the electrochemical sensor can be used to sensitively determine the biological function of neuron-like PC12 cells with negligible destruction and to explore the protective and regenerative impact of various substances on nerve cell model.

Simultaneous detection of C-reactive protein and lipopolysaccharide based on a dual-channel electrochemical biosensor for rapid Gram-typing of bacterial sepsis

Sepsis is a life-threatening multi-organ failure syndrome, with bacterial infections being the most common cause. Rapid Gram-typing is imperative to assist in antibiotic intervention. C-reactive protein (CRP) and lipopolysaccharide (LPS) are effective biomarkers for discerning the Gram type of bacteria but differ by several orders of magnitude in clinical detection, thereby impeding their simultaneous detection. And two independent methods are time-consuming and laborious. In this study, a dual-channel electrochemical biosensor was developed for simultaneous detection of LPS and CRP. Under optimal conditions, linear ranges of LPS (0.5-1000 pg/mL) and CRP (0.1-20 μg/mL) were obtained in line with the clinical evaluation scopes. In simulated sample tests, Gram-positive, Gram-negative, and healthy plasma samples were clearly distinguished by the developed biosensors, and these results were consistent with that of enzyme-linked immunosorbent assay (ELISA). In addition, the results of the plasma samples tested by the electrochemical biosensor matched those derived from blood cultures in the laboratory. Collectively, the electrochemical biosensor was expected to provide the scientific basis for the rapid Gram-typing and point-of-care detection of bacterial sepsis.

Precise Differentiation of Wobble-Type Allele via Ratiometric Design of a Ligase Chain Reaction-Based Electrochemical Biosensor for CYP2C19*2 Genotyping of Clinical Samples

Due to the comparable stability between the perfect-base pair and the wobble-base pair, a precise differentiation of the wobble-type allele has remained a challenge, often leading to false results. Herein, we proposed a ligase chain reaction (LCR)-based ratiometric electrochemical DNA sensor, namely, R-eLCR, for a precise typing of the wobble-type allele, in which the traditionally recognized "negative" signal of wobble-base pair-mediated amplification was fully utilized as a "positive" one and a ratiometric readout mode was employed to ameliorated the underlying potential external influence and improved its detection accuracy in the typing of the wobble-type allele. The results showed that the ratio between current of methylene blue (IMB) and current of ferrocene (IFc) was partitioned in three regions and three types of wobble-type allele were thus precisely differentiated (AA homozygote: IMB/IFc > 2; GG homozygote: IMB/IFc < 1; GA heterozygote: 1 < IMB/IFc < 2); the proposed R-eLCR successfully discriminated the three types of CYP2C19*2 allele in nine cases of human whole blood samples, which was consistent with those of the sequencing method. These results evidence that the proposed R-eLCR can serve as an accurate and robust alternative for the identification of wobble-type allele, which lays a solid foundation and holds great potential for precision medicine.

Multimodal Ochratoxin A-Aptasensor Using 3'-FAM-Enhanced Exonuclease I Tool and Magnetic Microbead Carrier

Thanks to its preparatory ease, close affinity, and low cost, the aptasensor can serve as a promising substitute for antibody-dependent biosensors. However, the available aptasensors are mostly subject to a single-mode readout and the interference of unbound aptamers in solution and non-target-induced transition events. Herein, we proposed a multimodal aptasensor for multimode detection of ochratoxin A (OTA) with cross-validation using the 3'-6-carboxyfluorescein (FAM)-enhanced exonuclease I (Exo I) tool and magnetic microbead carrier. Specifically, the 3'-FAM-labeled aptamer/biotinylated-cDNA hybrids were immobilized onto streptavidin-magnetic microbeads via streptavidin-biotin interaction. With the presence of OTA, an antiparallel G-quadruplex conformation was formed, protecting the 3'-FAM labels from Exo I digestion, and then anti-FAM-horseradish peroxidase (HRP) was bound via specific antigen-antibody affinity; for the aptamers without the protection of OTA, the distal ssDNA was hydrolyzed from 3' → 5', releasing 3'-FAM labels to the solution. Therefore, the OTA was detected by analyzing the "signal-off" fluorescence of the supernatant and two "signal-on" signals in electrochemistry and colorimetry through the detection of the coating magnetic microbeads in HRP's substrate. The results showed that the 3'-FAM labels increased the activity of Exo I, producing a low background due to a more thorough digestion of unbound aptamers. The proposed multimodal aptasensor successfully detected the OTA in actual samples. This work first provides a novel strategy for the development of aptasensors with Exo I and 3'-FAM labels, broadening the application of aptamer in the multimode detection of small molecules.

[Study on difference of effect of Huoxue drugs and Yiqi Huoxue drugs on tumor metastasis based on immune remodeling]

Tumor metastasis is an important cause of tumor treatment failure. Its molecular mechanism is closely related to tumor cells remodeling immune cells and immunosuppressive microenvironment, so as to create a suitable soil for tumor cell invasion and growth. &quot;Huoxue Huayu&quot; is one of the important therapeutic principles in cancer treatment, but the influence of Huoxue drugs on tumor metastasis has been controversial in clinical application. In this paper, we systematically summarized the comparative study of Huoxue drugs and Yiqi Huoxue drugs in tumor metastasis in recent years, and discussed the differences of molecular mechanisms of Huoxue drugs and Yiqi Huoxue drugs in anti-tumor metastasis from the perspective of immune remodeling, so as to provide scientific basis for clinical rational application of Huoxue drugs and Yiqi Huoxue drugs.

Improved carrier injection in GaN-based VCSEL via AlGaN/GaN multiple quantum barrier electron blocking layer

In this report, the improved lasing performance of the III-nitride based vertical-cavity surface-emitting laser (VCSEL) has been demonstrated by replacing the bulk AlGaN electron blocking layer (EBL) in the conventional VCSEL structure with an AlGaN/GaN multiple quantum barrier (MQB) EBL. The output power can be enhanced up to three times from 0.3 mW to 0.9 mW. In addition, the threshold current density of the fabricated device with the MQB-EBL was reduced from 12 kA/cm2 (9.5 mA) to 10.6 kA/cm2 (8.5 mA) compared with the use of the bulk AlGaN EBL. Theoretical calculation results suggest that the improved carrier injection efficiency can be mainly attributed to the partial release of the strain and the effect of quantum interference by using the MQB structure, hence increasing the effective barrier height of the conduction band.

The relationship between acid-suppressing drugs and phytobezoar formation: a retrospective analysis and discussion of phytobezoar formation

OBJECTIVES

Although phytobezoars are a rare cause of gastrointestinal obstruction, they are most commonly found in patients with previous gastric surgery. It is well known that predisposing factors of phytobezoar formation are ingestion of fruits containing soluble tannin, presence of dilute hydrochloric acid in the stomach, and gastric stasis or delayed emptying. We investigated whether intake of acid-suppressing drugs that neutralize gastric acidity or inhibit gastric acid secretion to constitute a hypo-acidic condition, increases the risk of phytobezoar formation.

MATERIALS AND METHODS

Between September 1992 and October 2008, 32 patients (24 male and 8 female) with gastrointestinal phytobezoars were diagnosed either surgically or endoscopically at the Tri-Service General Hospital, Taipei, Republic of China. The data were collected from hospital records and analyzed retrospectively.

RESULTS

Eighteen (56.25%) of all patients had previous gastric surgery and 6 (42.9%) of the 14 patients who had not undergone surgery had diabetes mellitus. The majority of admissions were during winter and spring (between October and March) (P < 0.01) and none of the patients had taken acid-suppressing drugs during the 6 months before detection of gastrointestinal phytobezoars.

CONCLUSIONS

In our study, intake of acid-suppressing drugs did not increase the risk of phytobezoar formation in patients with normal gastric motility. Moreover, we believe that the major factor in phytobezoar formation is gastric stasis or delayed emptying, which sufficiently prolongs the retention period of materials in the stomach, while dilute hydrochloric acid is a minor factor.

Broadband and omnidirectional antireflection employing disordered GaN nanopillars

Disordered GaN nanopillars of three different heights: 300, 550, and 720 nm are fabricated, and demonstrate broad angular and spectral antireflective characteristics, up to an incident angle of 60? and for the wavelength range of lambda=300-1800 nm. An algorithm based on a rigorous coupled-wave analysis (RCWA) method is developed to investigate the correlations between the reflective characteristics and the structural properties of the nanopillars. The broadband and omnidirectional antireflection arises mainly from the refractive-index gradient provided by nanopillars. Calculations show excellent agreement with the measured reflectivities for both s- and p- polarizations.

Enhanced light output from a nitride-based power chip of green light-emitting diodes with nano-rough surface using nanoimprint lithography

Enhanced light extraction from a GaN-based power chip (PC) of green light-emitting diodes (LEDs) with a rough p-GaN surface using nanoimprint lithography is presented. At a driving current of 350 mA and with a chip size of 1 mm × 1 mm packaged on transistor outline (TO)-cans, the light output power of the green PC LEDs with nano-rough p-GaN surface is enhanced by 48% when compared with the same device without a rough p-GaN surface. In addition, by examining the radiation patterns, the green PC LED with nano-rough p-GaN surface shows stronger light extraction with a wider view angle. These results offer promising potential to enhance the light output powers of commercial light-emitting devices by using the technique of nanoimprint lithography under suitable nanopattern design.

Estimation of beat-to-beat systolic blood pressure using pulse arrive time and pulse width derived from the photoplethysmogram

Continuous arterial blood pressure monitoring is essential in monitoring patients during surgical operation or in intensive care units. In this study, we propose a new method to estimate beat-to-beat systolic blood pressure by combining the pulse arrive time and normalized pulse width measurement. The method was examined in nine patients who were in ICU. Results shows the new method has higher linearity (0.8218) and better precision (3.0775) than the methods using either pulse arrive time or pulse width only.

InGaN self-assembled quantum dots grown by metal-organic chemical vapour deposition with growth interruption

Self-assembled InGaN quantum dots (QDs) were grown by metal-organic chemical vapour deposition with growth interruption at low V/III ratio and low growth temperature on sapphire substrates. The effects of the interruption time on the morphological and optical properties of InGaN QDs were studied. The results show that the growth interruption can modify the dimension and distribution of InGaN QDs, and cause the QD emission wavelength to blue shift with increasing interruption time. A density of InGaN QDs of about 4.5 × 10(10) cm(-2) with an average lateral size of 11.5 nm and an average height of 1.6 nm can be obtained by using a growth interruption time of 60 s.

Renal oncocytoma in acquired renal cystic disease

Renal oncocytoma is a rare benign tumor of the kidney that accounts for about 5% of renal tumors. Acquired renal cystic disease (ARCD) is commonly seen in dialyzed patients. However, the occurrence of renal oncocytoma in ARCD has rarely been reported. We report such a case in a 67-year-old man who had hypertension-associated end-stage renal disease and had received regular hemodialysis for 5 years. Radiologic diagnostic studies demonstrated a renal mass in the left atrophic cystic kidney that increased in size from 2 cm to 4 cm during 2 years of follow-up. Under the diagnosis of renal cell carcinoma, he received left radical nephrectomy. The pathologic examination revealed renal oncocytoma with a well-cirumscribed, homogenous, mahogany-brown tumor on a background of ARCD. Although patients with ARCD have a higher incidence of renal malignancies, renal oncocytoma may occur in these patients and may be managed conservatively.

Evidence for alterations in circulating low-molecular-weight antioxidants and increased lipid peroxidation in smokers on hemodialysis

BACKGROUND/AIM

Cardiovascular disease is the major cause of mortality in dialysis patients, accounting for about 40% of deaths in most large registries. Oxidative stress has been strongly implicated in the pathogenesis of these events. As end-stage renal disease is a state of elevated free radical activity, the aim of the present study was to investigate the negative impact of smoking in 57 male hemodialysis patients.

METHODS

The patients, who were 20-85 years of age (mean age 51.0 +/- 14 years), had been on hemodialysis for at least 6 months before participating in this study. Fasting blood sampling for serum lipid, albumin, urate and lipophilic antioxidants such as tocopherols, carotenes, ascorbate and lipid peroxides was performed.

RESULTS

The plasma malondialdehyde (MDA) concentration was significantly higher in hemodialysis patients who smoked compared to hemodialysis patients who were nonsmokers (1.92 +/- 0.52 vs. 1.59 +/- 0.42 nmol/ml, p = 0.006). No association was found between levels of MDA in smokers and parameters such as body mass index, serum cholesterol, serum triglycerides and smoking index. There were no significant differences in the plasma levels of uric acid, alpha-tocopherol, gamma-tocopherol, delta-tocopherol, alpha-carotene, beta-carotene and retinol between the two groups. A significantly lower level of plasma ascorbate was observed in hemodialysis patients who smoked compared to the nonsmoking hemodialysis patients or healthy controls (4.59 +/- 4.0 vs. 9.57 +/- 4.0 and 10.16 +/- 4.6 microg/ml, p < 0.05). Moreover, in smokers, the plasma levels of ascorbate were negatively correlated with the levels of plasma MDA (r = -0.43, p < 0.001) of each patient. Partial correlation analysis of the plasma levels of the measured antioxidants and the smoking index revealed a negative correlation between the plasma levels of lipid-normalized lycopene and the smoking index (r = -0.53, p < 0.05).

CONCLUSION

Our data suggest that cigarette smoking further increases plasma-circulating products of lipid peroxidation, which are already increased in nonsmoking hemodialysis patients as compared to matched healthy controls. The lower plasma levels of ascorbate in hemodialysis patients who smoke suggest that these patients may be more susceptible to oxidative tissue damage caused by smoking.

Lipophilic antioxidants and iron status in ESRD patients on hemodialysis

Cardiovascular disease remains the major cause of mortality in hemodialysis patients. Abnormal oxidative stress and impaired antioxidant defense may contribute to accelerated atherogenesis associated with uremia. As oxidative modification of lipids appears to be a prerequisite for the development of atherosclerotic lesions, lipophilic antioxidants may be protective. The aim of this study was to determine the plasma levels of lipophilic antioxidants in 82 hemodialysis patients and 30 controls and to investigate the influence of body iron status on the levels of lipophilic antioxidants. The patients were categorized into 3 groups according to their serum ferritin levels. We found that the plasma levels of lycopene, delta-tocopherol, gamma-tocopherol and retinol of hemodialysis patients were lower than those of controls. On the other hand, both absolute and lipid-normalized plasma lycopene levels were significantly reduced in those patients in the groups with higher ferritin levels as compared to those with lower ferritin levels. In addition, our study showed that the lipid-normalized plasma levels of beta-carotene and alpha-carotene of hemodialysis patients with higher ferritin levels were lower than those of the patients with lower levels. These data suggest that the plasma levels of lipophilic antioxidants are altered in end-stage renal disease on hemodialysis and may be considered as markers of oxidative stress in these patients. Most importantly, elevated serum ferritin levels may affect the levels of these lipophilic antioxidants.

Isolation of immunoglobulin from egg yolk by anionic polysaccharides

Isolation conditions of immunoglobulin in egg yolk (IgY) were optimized by the addition of various levels of Na-alginate (Alg), lambda-carrageenan (lambda-Cg), Na-carboxymethyl cellulose (CMC), and pectin (PC) to 6-fold diluted yolk. The mixtures were then reacted at pH 4.0-6.0 for 30 min. The optimal isolation conditions of IgY for Alg, lambda-Cg, and CMC were at the 0.1% level and at pH 5.0, while those for PC were at the 0.15% level and at the same pH. The remaining lipid and remaining protein in the supernatants thus obtained was 0.5-3.8% and 10-17%, respectively, and more than 90% of lipoproteins were precipitated. The IgY recovery was determined to be 33-74% by means of single radial immunodiffusion method when IgY was isolated under the optimal conditions. PC showed the best recovery of IgY, while lambda-Cg provided the least. The interactions between polysaccharides and lipoproteins were mainly ionic bonds, hydrophobic interactions, and hydrogen bonds as determined by the addition (0-2.0 M) of NaSCN or urea to the polysaccharide-lipoprotein precipitates.

Salmonella infection in total hip replacement--report of successful reimplantation and review of the literature

A case of Salmonella enteritidis group C infection following total hip replacement was treated by resectional arthroplasty and appropriate antibiotics. Total hip replacement with reimplantation of an antibiotic-impregnated cemented hip prosthesis was performed five months later. The postoperative course was smooth and hip function was good, without any sign of infection recurrence throughout 10 years of follow-up. The treatment protocol and clinical results are discussed along with a review of the literature.

Force decay of elastomeric chain--a serial study. Part II

This study was designed to evaluate the relaxation of elastomeric chain over time. The purposes were to compare the force decay curves of three variously stretched lengths, as well as to compare transparent and grey elastomeric chains. The elastomeric chains were fixed on a stainless steel framework that was submerged in 37 degrees C water bath for 6 weeks. The elastic forces of the chains were measured by a Dial-Type dynamometer, and recorded at the initial activation, first hour, eighth hour, twenty-fourth hour, third day, and then weekly to 6 weeks. The stretched length of the chains were decreased 0.5 mm per week. The results showed: (1) The sequence of stretch force at each time measurement of the Rocky Mountain clear energy chain was 40 mm > 35 mm > 30 mm. However, the percentage of remaining force was 40 mm < 35 mm < 30 mm. (2) The remaining force and the percentage of remaining force of the American Orthodontic short transparent chain were greater than the remaining force of the gray chain. (3) The remaining force and the percentage of remaining force of the Rocky Mountain clear chain with 40 mm stretch were greater than that of the American Orthodontic transparent and grey chains. (4) The effective force for canine retraction (184 gm) can be maintained by the Rocky Mountain energy chain with 40 mm, 35 mm, and 30 mm stretch for about 3 weeks, 1 week, and 3 days, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Bond strength with various etching times on young permanent teeth

Tensile bond strengths of an orthodontic resin cement were compared for 15-, 30-, 60-, 90-, or 120-second etching times, with a 37% phosphoric acid solution on the enamel surfaces of young permanent teeth. Fifty extracted premolars from 9- to 16-year-old children were used for testing. An orthodontic composite resin was used to bond the bracket directly onto the buccal surface of the enamel. The tensile bond strengths were tested with an Instron machine. Bond failure interfaces between bracket bases and teeth surfaces were examined with a scanning electron microscope and calculated with mapping of energy-dispersive x-ray spectrometry. The results of tensile bond strength for 15-, 30-, 60-, or 90-second etching times were not statistically different. For the 120-second etching time, the decrease was significant. Of the bond failures, 43%-49% occurred between bracket and resin interface, 12% to 24% within the resin itself, 32%-40% between resin and tooth interface, and 0% to 4% contained enamel fragments. There was no statistical difference in percentage of bond failure interface distribution between bracket base and resin, resin and enamel, or the enamel detachment. Cohesive failure within the resin itself at the 120-second etching time was less than at other etching times, with a statistical significance. To achieve good retention, to decrease enamel loss, and to reduce moisture contamination in the clinic, as well as to save chairside time, a 15-second etching time is suggested for teenage orthodontic patients.(ABSTRACT TRUNCATED AT 250 WORDS)