Evaluation of two laboratory model methods for diarrheal irritable bowel syndrome.

BACKGROUND: Diarrheal irritable bowel syndrome (IBS-D) is a common chronic functional gastrointestinal disorder, and the underlying pathogenic mechanism is still unclear. Animal models that mimic the pathological state of IBS-D patients were constructed to provide a reference for later drug research and model development. METHODS: The IBS-D model was induced using restraint stress and chemical stimulation (rhubarb), and rats were divided into normal control group (NC), chemically stimulated group (CS), and restraint stress group (RS). Visceral motility responses to Colorectal Balloon Dilation (CRD) were measured by Abdominal Withdrawal Reflex (AWR); evaluation of faecal properties and water content; determination of colonic tissue tight junction (TJ) mRNA expression by RT-PCR; measurement of inflammatory cytokines by ELISA; and intestinal flora and short chain fatty acids. RESULTS: Compared to NC group, CS and RS group rats showed increased intestinal sensitivity and Bristol stool score, significant diarrheal symptoms and weight loss. Mucin 2, ZO-1, OCLN, CLDN4 mRNA expression was reduced and the intestinal mucosal barrier function was diminished. In addition, the levels of inflammatory factors IL-1ß, IL-6, IL-8, IL-10 and TNF-α increased, the abundance and diversity of intestinal flora decreased, the content of beneficial bacteria such as Bifidobacteria decreased, and SCFAs such as acetic acid, propionic acid and butyric acid decreased to different degrees. Although, no significant difference was observed for any molecular and inflammatory marker, but compared to CS group, RS group had less water in the stool, higher visceral sensitivity, and higher relative abundance of beneficial intestinal bacteria such as Actinobacteria. CONCLUSION: In conclusion, restraint stress combined with chemical stimulation can mimic the pathological state of diarrhoea symptoms, visceral hypersensitivity, reduced intestinal mucosal barrier permeability, immune regulatory dysfunction and dysbiosis in IBS-D patients. However, herbs with antibacterial effects such as rhubarb and senna, for example, are not suitable as the first choice for chemical stimulation, as they may lead to a decrease in harmful bacteria and an increase in beneficial bacteria in the intestinal fraction and do not perfectly mimic the imbalanced state of intestinal flora in IBS-D patients, while restraint stress may be a key factor in modelling.

Flattened fiber-optic ATR sensor enhanced by silver nanoparticles for glucose measurement.

This paper proposes a novel fiber attenuated total reflection (ATR) sensor with silver nanoparticles (AgNPs) on the flattened structure based on mid-infrared spectroscopy for detecting low concentration of glucose with high precision. The flattened structure was designed to add the effective optical path length to improve the sensitivity. AgNPs were then deposited on the surface of the flattened area of the fiber via chemical silver mirror reaction for further improving the sensitivity by enhancing the infrared absorption. Combining the AgNPs modified flattened fiber ATR sensor with a CO2 laser showed a strong mid-infrared glucose absorption, with an enhancement factor of 4.30. The glucose concentration could be obtained by a five-variable partial least-squares model with a root-mean-square error of 4.42 mg/dL, which satisfies clinical requirements. Moreover, the fiber-based technique provides a pretty good method to fabricate miniaturized ATR sensors that are suitable to be integrated into a microfluidic chip for continuous glucose monitoring with high sensitivity.

U-shaped fiber-optic ATR sensor enhanced by silver nanoparticles for continuous glucose monitoring.

An implantable U-shaped fiber ATR sensor enhanced by silver nanoparticles on cylindrical surface was presented for continuous glucose monitoring to overcome the drawbacks of traditional glucose sensing technique based on enzyme electrodes. A U-shaped structure was addressed to increase effective optical length at limited implantable space to enhance the sensitivity of fiber ATR sensor. A novel method to fabricate silver nanoparticles on cylindrical surface of U-shaped fiber ATR sensor based on chemical reduction of its silver halide material directly without any preliminary nanoparticles synthesis and following covalent bond or self-assembly was proposed. Five glucose absorption wavelengths in the mid-infrared band were employed for specific glucose monitoring. The experimental results indicate that the sensitivity and resolution of the silver-nanoparticle-enhanced U-shaped fiber-optic ATR sensor are approximately three times those of a conventional one. The high sensitivity and low-noise performance makes it promising for in vivo glucose monitoring in the future clinical applications.

[Study on detection methods of interstitial fluid glucose concentration based on infrared attenuated total reflection].

Measuring the glucose concentrations in the interstitial fluid is currently the main method to achieve the continuous blood glucose monitoring. The MIR-ATR(Mid-infrared, Attenuated Total Reflection)Spectroscopy has prominent advantage on the analysis of small biological molecule for composition information like the glucose, but it is still an unresolved problem that how to detect the subcutaneous glucose concentration by using the MIR-ATR Spectroscopy. In the present paper, we carry out the experiment based on MIR-ATR for the detection of subcutaneous glucose information on both the natural state and the penetration state based on the theoryanalysis of MIR penetration depth. Firstly, collect spectral data of the subcutaneous glucose concentration of human finger on the natural state were collected as the light shined the skin directly, and it was discussed whether the MIR can penetrate the skin to get the information of subcutaneous glucose. On this basis, collect spectral data of the subcutaneous glucose concentration of human finger at the penetration state were collected when the Interstitial fluid is permeated to the surface layer by using low-frequency ultrasound and vacuum, then it analyzed that whether it can detect the glucose-specific information or not. As the two-dimensional correlation spectroscopy has high resolution and good versatility, it is widely used to analyze the inter-molecular reaction and judge the absorption peaks information in many fields including the MIR spectroscopy field, so we choose the Two-dimensional correlation spectroscopy to analyze the information of subcutaneous glucose concentration at the natural state and the penetration state. The experiment result shows that the MIR-ATR spectroscopy can't be applied in the detection of subcutaneous glucose concentrationdirectly, and it is a promising direction to make the Interstitial fluid permeated to the surface layer by the physical methods or chemical methods.

[Application of mid-infrared wavelength tunable laser in glucose determination].

The authors proposed a method of control and stabilization for laser emission wavelengths and power, and presented the mid-infrared wavelength tunable laser with broad emission spectrum band of 9.19-9.77 microm, half wave width of 4 cm(-1), spectral resolution of 2.7 x 10(4) and max power of 800 mW with fluctuation < 0.8% in the present paper. The tunable laser was employed as the light source in combination with ATR sensor for glucose measurement in PBS solution. In our experiments, absorbance at the five laser emission wavelengths, including 1 081, 1 076, 1 051, 1 041 and 1 037 cm(-1) in the 9R and 9P band of the laser emission spectrum, all correlates well with the glucose concentration (R2 > 0.99, SD < 0.0004, P < 0.000 1). Especially, the sensitivity of this laser spectroscopy system is about 4 times as high as that of traditional FTIR spectrometer.

In vitro glucose measurement using tunable mid-infrared laser spectroscopy combined with fiber-optic sensor.

Because mid-infrared (mid-IR) spectroscopy is not a promising method to noninvasively measure glucose in vivo, a method for minimally invasive high-precision glucose determination in vivo by mid-IR laser spectroscopy combined with a tunable laser source and small fiber-optic attenuated total reflection (ATR) sensor is introduced. The potential of this method was evaluated in vitro. This research presents a mid-infrared tunable laser with a broad emission spectrum band of 9.19 to 9.77[Formula: see text](1024~1088 cm(-1)) and proposes a method to control and stabilize the laser emission wavelength and power. Moreover, several fiber-optic ATR sensors were fabricated and investigated to determine glucose in combination with the tunable laser source, and the effective sensing optical length of these sensors was determined for the first time. In addition, the sensitivity of this system was four times that of a Fourier transform infrared (FT-IR) spectrometer. The noise-equivalent concentration (NEC) of this laser measurement system was as low as 3.8 mg/dL, which is among the most precise glucose measurements using mid-infrared spectroscopy. Furthermore, a partial least-squares regression and Clarke error grid were used to quantify the predictability and evaluate the prediction accuracy of glucose concentration in the range of 5 to 500 mg/dL (physiologically relevant range: 30~400 mg/dL). The experimental results were clinically acceptable. The high sensitivity, tunable laser source, low NEC and small fiber-optic ATR sensor demonstrate an encouraging step in the work towards precisely monitoring glucose levels in vivo.

Exploring the metabolic network of the epidemic pathogen Burkholderia cenocepacia J2315 via genome-scale reconstruction.

BACKGROUND: Burkholderia cenocepacia is a threatening nosocomial epidemic pathogen in patients with cystic fibrosis (CF) or a compromised immune system. Its high level of antibiotic resistance is an increasing concern in treatments against its infection. Strain B. cenocepacia J2315 is the most infectious isolate from CF patients. There is a strong demand to reconstruct a genome-scale metabolic network of B. cenocepacia J2315 to systematically analyze its metabolic capabilities and its virulence traits, and to search for potential clinical therapy targets. RESULTS: We reconstructed the genome-scale metabolic network of B. cenocepacia J2315. An iterative reconstruction process led to the establishment of a robust model, iKF1028, which accounts for 1,028 genes, 859 internal reactions, and 834 metabolites. The model iKF1028 captures important metabolic capabilities of B. cenocepacia J2315 with a particular focus on the biosyntheses of key metabolic virulence factors to assist in understanding the mechanism of disease infection and identifying potential drug targets. The model was tested through BIOLOG assays. Based on the model, the genome annotation of B. cenocepacia J2315 was refined and 24 genes were properly re-annotated. Gene and enzyme essentiality were analyzed to provide further insights into the genome function and architecture. A total of 45 essential enzymes were identified as potential therapeutic targets. CONCLUSIONS: As the first genome-scale metabolic network of B. cenocepacia J2315, iKF1028 allows a systematic study of the metabolic properties of B. cenocepacia and its key metabolic virulence factors affecting the CF community. The model can be used as a discovery tool to design novel drugs against diseases caused by this notorious pathogen.

[Epidemiological study of high risk human papillomavirus infection in 25 to 54 years old married women in Beijing.].

OBJECTIVE: To investigate high risk human papillomavirus (HR-HPV) prevalence among married women in Beijing and to study the high risk factors. METHODS: During March 2007 to September 2008, a total of 6185 married women sampled from 137 communities in 12 districts were screened by HR-HPV DNA test and cytological test. The interview was carried out with unified questionnaires. The database was set up and twice entered in EpiData 3.0. After checked up, the data were analyzed in SPSS 15.0. RESULTS: (1) The HR-HPV infection rate was 9.89%. The HR-HPV infection rate of the city zone, the suburb and the exurb were 9.34%, 10.51% and 9.51% (P > 0.05). The HR-HPV infection rate of the native and the outlander were 9.53%, 11.30% (P < 0.05). (2) The age distribution of HR-HPV infection was that the rate was around 10% among 25 to 44 age groups, which was the highest (11.21%) in 30 to 34 age group; then the rate was descended as the age raising, the rate of 50 to 54 age group was the lowest (7.78%). (3) Multiple logistic regression showed that the related risk factors of HR-HPV infection mainly included 1000 RMB and above of family income per person per month, possessing more than 1 sexual partner of her husband, outlander and high levels of education. (4) The prevalence of cervical intraepithelial neoplasia (CIN) in HR-HPV positive group was significantly higher than that in HR-HPV negative group (29.76% vs 3.32%, P < 0.01). CONCLUSIONS: (1) The HR-HPV infection rate among aged 25 to 54 years was 9.9% and there was no significant difference in area distribution. (2) The high risk population which should strengthen screening was the married bearing-age women with high level of family income, outlander, high levels of education and her husband possessing more than 1 sexual partner. (3) HR-HPV infection is the main risk factor for CIN and cervical cancer, while does not provide a causal relationship with them. The high risk population should be checked regularly to understand the development of HR-HPV infection and CIN incidence.