Abstract P4-03-12: diagnostic value and clinical significance of integrin αvβ3 in breast mass

Background: Integrins are cell adhesion molecules that widely exists in cell surface, it is a hetero-dimeric protein bound non-covalently by α, β subunit. It plays the role of mediation during interaction of the αvβ3 and the corresponding receptor in signal transduction pathway, integrin αvβ3 is much richer in the surface of neovascular endothelial cells and tumor cells, while poor in the blood vessels and normal tissues. Therefore, it plays an important role in a variety of malignant tumors of the occurrence, development and metastasis processes. We find tumors constituted with neovascularization earlier by marker of integrin αvβ3.

Materials & Methods: We give patients who consider as breast mass intravenous injection of99mTc-3PRGD2 as a tracer preoperatively by SPECT/CT imaging and treat with surgery within a week, then make pathological examination with tumor tissues removed by needle biopsy. Then we make a retrospective analysis and evaluation of patients scanned completely by qualitative and semi-quantitative methods. All patients have signed the informed consent form before the test, together with the recognition of the Ethics Committee.

Results: From December 2011 to May 2012, a total of 245 patients were scanned and operated with clear paraffin pathological diagnosis by intravenous injection of99mTc −3PRGD2. Among them, a total of 106 patients (167 developing lesions) were positive with radionuclide imaging results, 139 patients were negative. Diseases of 106 patients are divided into four series: breast cancer, inflammation mastitis, phyllodes tumor and partly with fibroadenoma. They have in common that there is a clear flow signal in and around lesions by color Doppler ultrasound.

Discussion: After study on 245 patients, we created a molecular imaging tool to show expression of integration αvβ3 in order to assess tumor angiogenesis. Integrin αvβ3 plays an important role in physiological and pathological processes of malignant tumor, such as inflammation, tumor angiogenesis, invasion and metastasis etc. Therefore, its high expression is easy to find in cancer, mastitis, most of the phyllodes tumor and part of fiber adenoma with peripheral lesions. For patients with clear imaging, we make comprehensive analysis based on their ultrasound, mammography, MRI or CT results, which can generally contributes to the early diagnosis of disease in clinical. The detection of sentinel lymph node should be avoided for the patients with axillary lymph node imaging, who are clearly diagnosed as breast carcinoma with axillary lymph node metastases. These peptides are not only tumor receptor-targeted imaging agents with potential clinical value, but also laid a solid foundation for further development of receptor-targeted radionuclide therapy to solid tumors. The method marked with high expression of integrin αvβ3 in the tumor vascular endothelial cells by99mTc-3PRGD2 and SPECT/CT imaging mode has a broad prospect in the early diagnosis of tumor, lesion detection and efficacy evaluation. In the future, we may also find the new imaging agent with more accuracy and specificity. We believe that there will be more and more breast cancer patients benefit from the technology development of ECT/CT examination.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-03-12.

Validation of a lameness model in sows using physiological and mechanical measurements

The objective of this study was to develop a validated, transient, chemically induced lameness model in sows using subjective and objective lameness detection tools. Experiment 1 determined an effective joint injection technique based on volume and placement of dye using feet collected from 9 finisher pigs and 10 multiparity cull sow carcasses. Experiment 2 confirmed the injection technique in live animals and produced a transient clinical lameness in 4 anesthetized sows injected with amphotericin B (15 mg/mL) in the distal interphalangeal joints of the claw. Clinical lameness was assessed by a categorical lameness scoring system, and a postmortem visual confirmation of joint injection technique was obtained. In Exp. 3, 6 sows were injected with 0, 10, or 15 mg/mL amphotericin B in either the left or right hind foot and were monitored until clinical resolution. Treated sows demonstrated elevated clinical lameness scores. These changes resolved by 7 d after lameness induction. Control sows injected with sterile saline developed a clinical lameness score of 0.5, which resolved 72 h post injection. In Exp. 4, 36 sows were injected with 10 mg/mL amphotericin B in 1 of 4 injection sites (left front claws, right front claws, left rear claws, and right rear claws). All injected sows exhibited a decrease in maximum pressure, stance time, and number of sensors activated on the GaitFour (P < 0.05) sensor system. A static force plate also demonstrated a decrease in weight (kg) being placed on the injected foot when all feet were injected (P ≤ 0.05). Injection of amphotericin B induced a predictable acute lameness that resolved spontaneously and is an effective method to model lameness in sows.

Identifying crosstalk of mTOR signaling pathway of lobular breast carcinomas

BACKGROUND

Invasive lobular carcinoma (ILC) and its variants represent 5% to 15% of all invasive breast cancers diagnoses annually. AS a serine/threonine kinase, mammalian target of rapamycin (mTOR) is often a downstream effector of PI3K/Akt (phosphatidyl inositol 3-kinase/protein kinase B) signaling pathway in breasts and many types of cancer cells. Therefore, agents that target mTOR in direct or indirect manner are being developed in anti-cancer therapy.

AIM

In this study, our objective here was to explore more crosstalk pathway with mTOR signaling pathway.

MATERIALS AND METHODS

We collected pathways data from published database, then based on bioinformatics methods we analyzed the significant pathways in the database, additionally, the crosstalk pathways were also analyzed which were defined as those pathways which have the overlapping genes with each other.

RESULTS

As we expected, the results showed that Notch signaling pathway (hsa04330), Regulation of autophagy (hsa04140), and Adipocytokine signaling pathway (hsa04920) were linked to mTOR signaling pathway. All of them have been demonstrated participate in breast cancer progression.

CONCLUSIONS

We obtained some key pathways that crosstalked with mTOR signaling pathway, we hope our study could provide novel therapeutic approaches for breast cancer.

Abnormal glucose tolerance and insulin secretion in pancreas-specific Tcf7l2-null mice

AIMS/HYPOTHESIS

Individuals carrying type 2 diabetes risk alleles in TCF7L2 display decreased beta cell levels of T cell factor 7 like-2 (TCF7L2) immunoreactivity, and impaired insulin secretion and beta cell sensitivity to glucagon-like peptide 1 (GLP-1). Here, we sought to determine whether selective deletion of Tcf7l2 in mouse pancreas impairs insulin release and glucose homeostasis.

METHODS

Pancreas-specific Tcf7l2-null (pTcf7l2) mice were generated by crossing mice carrying conditional knockout alleles of Tcf7l2 (Tcf7l2-flox) with mice expressing Cre recombinase under the control of the Pdx1 promoter (Pdx1.Cre). Gene expression was assessed by real-time quantitative PCR and beta cell mass by optical projection tomography. Glucose tolerance, insulin secretion from isolated islets, and plasma insulin, glucagon and GLP-1 content were assessed by standard protocols.

RESULTS

From 12 weeks of age, pTcf7l2 mice displayed decreased oral glucose tolerance vs control littermates; from 20 weeks they had glucose intolerance upon administration of glucose by the intraperitoneal route. pTcf7l2 islets displayed impaired insulin secretion in response to 17 (vs 3.0) mmol/l glucose (54.6 ± 4.6%, p < 0.01) or to 17 mmol/l glucose plus 100 nmol/l GLP-1 (44.3 ± 4.9%, p < 0.01) compared with control islets. Glp1r (42 ± 0.08%, p < 0.01) and Ins2 (15.4 ± 4.6%, p < 0.01) expression was significantly lower in pTcf7l2 islets than in controls. Maintained on a high-fat (but not on a normal) diet, pTcf7l2 mice displayed decreased expansion of pancreatic beta cell volume vs control littermates. No differences were observed in plasma insulin, proinsulin, glucagon or GLP-1 concentrations.

CONCLUSIONS/INTERPRETATION

Selective deletion of Tcf7l2 in the pancreas replicates key aspects of the altered glucose homeostasis in human carriers of TCF7L2 risk alleles, indicating the direct role of this factor in controlling beta cell function.

Body fat percentage is associated with cardiometabolic dysregulation in BMI-defined normal weight subjects

BACKGROUND AND AIMS

Nearly 25% of normal weight individuals display abnormal metabolic profiles associated with obesity. As a wide range in body fat percentage (%BF) exists for BMI-defined normal weight individuals, we investigated whether elevated %BF (determined using DXA) was associated with cardiometabolic dysregulation among 977 normal weight subjects (192 men, 785 women) from the Canadian province of Newfoundland and Labrador.

METHODS AND RESULTS

BMI and %BF were measured after a 12-h fasting period. Cardiometabolic abnormalities considered included elevated triglyceride, glucose and hsCRP levels, decreased HDL cholesterol, insulin resistance, and hypertension. Subjects were classified as metabolically healthy (0 or 1 cardiometabolic abnormality) or abnormal (≥2 cardiometabolic abnormalities) and divided into sex-specific %BF tertiles as follows: low (≤15.2% men, ≤29.7% women), medium (15.3-20.7%% men, 29.8-34.9%% women) and high (≥20.8% men, ≥35.0% women). The prevalence of the metabolically abnormal phenotype was higher among medium and high %BF subjects (12.0% and 19.5%, respectively) compared to the low group (7.4%; p < 0.05). Furthermore, the odds of being metabolically abnormal were 1.61 (95% CI 0.94-2.77) for medium %BF subjects compared to the low group and nearly tripled for high %BF subjects (OR 2.73, 95% CI 1.63-4.86). ORs remained significant after further adjustment for waist circumference.

CONCLUSION

Our findings indicate that those with elevated %BF are at increased risk of developing cardiometabolic disease despite having a normal BMI. Future development of adequate screening tools to identify these individuals is crucial to the prevention of obesity-associated disease.

320-detector row CT coronary angiography: effects of heart rate and heart rate variability on image quality, diagnostic accuracy and radiation exposure

OBJECTIVES

To evaluate the effects of heart rate and heart rate variability on image quality, patient dose and diagnostic accuracy of 320-detector row CT.

METHODS

94 patients were prospectively enrolled. Heart rate was defined as the mean value of different intervals elapsing between two consecutive R waves in an electrocardiogram (R-R intervals) and the heart rate variability was calculated as the standard deviation from the average heart rate. The image quality was evaluated by four grades, according to motion artefacts ("step artefacts" and "blurring artefacts"). The diagnostic accuracy was analysed in 43 patients who were scheduled for invasive coronary angiography (ICA). The coeffects of heart rate and heart rate variability on image quality, radiation dose and diagnostic accuracy were evaluated by multivariate regression.

RESULTS

The mean image quality score was 1.2 ± 0.5 and the mean effective dose was 14.8 ± 9.8 mSv. The results showed that heart rate (74.0 ± 11.2 beats per minute) was the single factor influencing image quality (p<0.001) and radiation dose (p<0.001), while heart rate variability (3.7 ± 4.6) had no significant effect on them (p=0.16 and p=0.47, respectively). For 43 patients who underwent ICA, heart rate and heart rate variability showed no influence on the accuracy (p=0.17 and p=0.12, respectively). Overall sensitivity was 97.4% (37/38), specificity was 99.4% (351/353), positive predictive value was 94.9% (37/39) and negative predictive value was 99.7% (351/352).

CONCLUSION

320-detector row CT, with improved longitudinal coverage of detector, resolves step artefact and high patient dose caused by irregular heart rate. However, it is still recommended to control heart rate to a lower level to eliminate blurring artefact and radiation dose.

A novel stress monitoring method through stress-induced respiratory alterations: non-contact measurement of respiratory V(T)/T(I) alterations induced by stressful sound using a 10 GHz microwave radar

We have developed a non-contact stress monitoring system which measures respiratory V(T)/T(I) (tidal volume/inspiration time) alterations using a 10 GHz microwave radar. The measurable distance of the system is 50 cm, which is 10 times longer than our previously developed stress monitoring system which measures heart rate variability using a 24-GHz microwave-radar. The study was conducted with eight subjects (23 ± 1 years old) to evaluate the efficacy of the system. An audio stimulus at 95 dB sound pressure level was presented to the subjects following a silent period of 120 seconds. During the silent period, V(T)/T(I) averaged 826 ± 384 ml s(-1), while it increased significantly (p < 0.05) with an average of 1227 ± 704?ml s(-1) during audio stimulus low frequency component (LF)/high frequency component (HF), which reflects sympatho-vagal valance, showed a peak during audio stimuli. This paper aims to study the efficacy of the non-contact stress monitoring system for its future applications in many fields including health and safety.

Percutaneous vertebroplasty for pain management in spinal metastasis with epidural involvement

Percutaneous vertebroplasty (PVP) has been widely used for the treatment of painful malignant lesions of the spine. Spinal metastasis with epidural involvement, with or without symptoms of neurologic compression, is regarded by some authors as a contraindication or relative contraindication to the procedure. To evaluate safety and effectiveness of PVP in pain management of spinal metastasis with epidural involvement, we retrospectively analyzed PVP in 32 patients with metastatic disease, who presented with at least one vertebral lesion with destruction of the posterior vertebral body wall or epidural extension of tumor. Among these patients, nine had signs of spinal cord or cauda equina compression. Procedural safety was evaluated by any post-procedure adverse events. The PVP analgesic efficacy was evaluated by follow-up neurological examination. Pain intensity was scored on a visual analog scale scored from 0 (no pain) to 10 (maximum pain intensity). The effective pain relief was defined as at least 50% improvement in pain score as compared with pre- procedure baseline. Follow-up assessments were performed at 1 day; 1 week; 1, 3, and 6 months after the procedure. Fifty-three vertebrae in 32 patients were treated in this group. Analgesic efficacy in survival patients was rated at 97% (31/32) at 1day and 1 week, 86.7% (26/30) at 1 month, 82.3% (24/29) at 3 months, and 76.9% (20/26) at 6 months after procedure. Leakage of PMMA was detected in 64% (33/53) treated vertebrae. No systemic complications were observed in all treated patients.

Morphology development and size control of poly(trimethylene terephthalate) nanofibers prepared from poly(trimethylene terephthalate)/cellulose acetate butyrate in situ fibrillar composites

Formation of nano-fibrillar composite structures provides an effective method for preparing thermoplastic nanofibers. By mixing two immiscible thermoplastic polymers in a twin screw extruder, poly(trimethylene terephthalate) (PTT) formed nano-fibrillar morphology in cellulose acetate butyrate (CAB) matrix, and then PTT nanofibers were obtained from PTT/CAB in situ fibrillar composites after removing the matrix phase of CAB. Blend ratio, shear rate, and draw ratio were three important parameters in the extrusion process, which could affect the shape and size of nanofibers. By varying the process conditions, average diameter of PTT nanofibers could be controlled in the range of 80-400 nm. Besides this, the mechanism of nano-fibrillar formation in PTT/CAB blends was also studied by collecting samples at different stages in the extruder. The morphology developmental trends of PTT dispersed phase with different blend ratios were nearly the same. From initial to metaphase and later phase development, the PTT dispersed component undergo the formation of sheets, holes, and network structures, then the size reduction and formation of nanofibers.

Optimal systolic and diastolic reconstruction windows for coronary CT angiography using 320-detector rows dynamic volume CT

AIM

To investigate the optimal pattern of systolic and diastolic reconstruction windows for coronary computed tomography (CT) angiography using 320-detector rows dynamic volume CT (DVCT).

MATERIAL AND METHODS

A prospective analysis was performed on the data from 77 patients who were admitted between December 2008 and July 2009 for DVCT. The images were reconstructed in 10% steps throughout the 10-100% of R-R interval. Data sets for the three major coronary arteries [right coronary artery (RCA), left anterior descending artery (LAD), and left circumflex artery (LCX)] were evaluated by two independent readers. The quality of the images from each examined artery was graded from 1 (no motion artefacts) to 4 (severe motion artefacts over the entire vessel). The optimal systolic and diastolic reconstruction windows and the relationship between image quality and heart rate (HR) were analysed. The HR at which the optimal reconstruction window shifted from diastole to systole was predicted.

RESULTS

The average HR during imaging was 69.5±12.8 beats/min (range 46-102beats/min). HR was positively correlated with the proportion of systole (r=0.78, p<0.001). As HR increased, the optimal reconstruction windows shifted to later phases in both systole and diastole. Image quality for optimal systolic and diastolic reconstructions both deteriorated significantly with higher HRs (r=0.38, p<0.001; r=0.82, p<0.001). However, image quality in systolic reconstructions did not deteriorate as much as in diastolic reconstructions. The cut-off HRs at which optimal reconstruction intervals turned from diastole to systole was 90.8beats/min.

CONCLUSIONS

In patients with a low HR, the optimal coronary reconstruction window is in mid-late diastole. As the HR increases, systolic reconstruction often yields superior image quality compared with diastolic reconstruction.

Per-arnt-sim (PAS) domain-containing protein kinase is downregulated in human islets in type 2 diabetes and regulates glucagon secretion

AIMS/HYPOTHESIS

We assessed whether per-arnt-sim (PAS) domain-containing protein kinase (PASK) is involved in the regulation of glucagon secretion.

METHODS

mRNA levels were measured in islets by quantitative PCR and in pancreatic beta cells obtained by laser capture microdissection. Glucose tolerance, plasma hormone levels and islet hormone secretion were analysed in C57BL/6 Pask homozygote knockout mice (Pask-/-) and control littermates. Alpha-TC1-9 cells, human islets or cultured E13.5 rat pancreatic epithelia were transduced with anti-Pask or control small interfering RNAs, or with adenoviruses encoding enhanced green fluorescent protein or PASK.

RESULTS

PASK expression was significantly lower in islets from human type 2 diabetic than control participants. PASK mRNA was present in alpha and beta cells from mouse islets. In Pask-/- mice, fasted blood glucose and plasma glucagon levels were 25 ± 5% and 50 ± 8% (mean ± SE) higher, respectively, than in control mice. At inhibitory glucose concentrations (10 mmol/l), islets from Pask-/- mice secreted 2.04 ± 0.2-fold (p < 0.01) more glucagon and 2.63 ± 0.3-fold (p < 0.01) less insulin than wild-type islets. Glucose failed to inhibit glucagon secretion from PASK-depleted alpha-TC1-9 cells, whereas PASK overexpression inhibited glucagon secretion from these cells and human islets. Extracellular insulin (20 nmol/l) inhibited glucagon secretion from control and PASK-deficient alpha-TC1-9 cells. PASK-depleted alpha-TC1-9 cells and pancreatic embryonic explants displayed increased expression of the preproglucagon (Gcg) and AMP-activated protein kinase (AMPK)-alpha2 (Prkaa2) genes, implying a possible role for AMPK-alpha2 downstream of PASK in the control of glucagon gene expression and release.

CONCLUSIONS/INTERPRETATION

PASK is involved in the regulation of glucagon secretion by glucose and may be a useful target for the treatment of type 2 diabetes.

Clinical Significance of CDH13 Promoter Methylation in Serum Samples from Patients with Bladder Transitional Cell Carcinoma

H-cadherin (CDH13; also known as T-cadherin), which functions as a tumour suppressor, is frequently silenced by promoter methylation in human cancers including bladder transitional cell carcinoma (TCC). This study investigated the clinical significance of methylation of the CDH13 gene promoter in serum from patients with bladder TCC. Methylation status of CDH13 in serum samples from 127 patients with primary bladder TCC and 41 healthy volunteers (controls) was examined by methylation-specific polymerase chain reaction. CDH13 methylation was found in 39 patients with bladder TCC (30.7%) but in no controls. CDH13 methylation was significantly associated with advanced tumour stage, high-grade tumour, large tumour size, tumour recurrence and poor prognosis. The results suggested that CDH13 methylation in serum may be a potential predictive biomarker for malignancy in bladder TCC, and an independent pre-therapeutic predictor of outcome. Demonstration of CDH13 methylation in serum may facilitate in the prediction of which patients require more aggressive additional post-operative systemic therapy.

Enhancing the removal of arsenic, boron and heavy metals in subsurface flow constructed wetlands using different supporting media

The presence of arsenic and heavy metals in drinking water sources poses a serious health risk due to chronic toxicological effects. Constructed wetlands have the potential to remove arsenic and heavy metals, but little is known about pollutant removal efficiency and reliability of wetlands for this task. This lab-scale study investigated the use of vertical subsurface flow constructed wetlands for removing arsenic, boron, copper, zinc, iron and manganese from synthetic wastewater. Gravel, limestone, zeolite and cocopeat were employed as wetland media. Conventional gravel media only showed limited capability in removing arsenic, iron, copper and zinc; and it showed virtually no capability in removing manganese and boron. In contrast, alternative wetland media: cocopeat, zeolite and limestone, demonstrated significant efficiencies--in terms of percentage removal and mass rate per m3 of wetland volume--for removing arsenic, iron, manganese, copper and zinc; their ability to remove boron, in terms of mass removal rate, was also higher than that of the gravel media. The overall results demonstrated the potential of using vertical flow wetlands to remove arsenic and metals from contaminated water, having cocopeat, zeolite or limestone as supporting media.

A sensitive and specific HPGPC-FD method for the study of pharmacokinetics and tissue distribution of Radix Ophiopogonis polysaccharide in rats

Interest in antimyocardial ischemic activity of a graminan-type fructan with a weight average molecular weight of 4.8 kDa extracted from Radix Ophiopogonis (ROP) has necessitated the study of its pharmacokinetics and tissue distribution. For that, a simple HPGPC-FD method was developed for the sensitive and specific determination of FITC-ROP (fluorescein-isothiocyanate-labeled ROP) in plasma and rat tissues (heart, liver, spleen, lung, kidney, brain and stomach). The analyte was separated on a Shodex Sugar KS-802 high-performance gel column with 0.1 M phosphate buffer (pH 7.0) as mobile phase at a flow rate of 0.5 mL/min, and fluorescence detection at lambda(ex) 495 nm and lambda(em) 515 nm. The calibration curve for FITC-ROP was linear over the range 0.25-20.0 or 50.0 microg/mL in all studied biosamples with correlation coefficients > 0.995. The inter-day and intra-day precisions of analysis were not more than 10%, and assay accuracy ranged from 93 to 105% for plasma and from 89 to 108% for tissue homogenates. This method has been confirmed here to be suitable for the study of pharmacokinetics and tissue distribution of ROP and the achieved results are highly instructive for the further pharmaceutical development of ROP, suggesting the promising application of the method to the increasingly important carbohydrate-based drugs.

Design of a Si-based lattice-matched room-temperature GeSn/GeSiSn multi-quantum-well mid-infrared laser diode

This paper presents modeling and simulation of a silicon-based group IV semiconductor injection laser diode in which the active region has a multiple quantum well structure formed with Ge(0.9)Sn(0.1) quantum wells separated by Ge(0.75)Si(0.1)Sn(0.15) barriers. These alloy compositions were chosen to satisfy three conditions simultaneously: a direct band gap for Ge(0.9)Sn(0.1), type-I band alignment between Ge(0.9)Sn(0.1) and Ge(0.75)Si(0.1)Sn(0.15,) and a lattice match between wells and barriers. This match ensures that the entire structure can be grown strain free upon a relaxed Ge(0.75)Si(0.1)Sn(0.15) buffer on a silicon substrate - a CMOS compatible process. Detailed analysis is performed for the type I band offsets, carrier lifetime, optical confinement, and modal gain. The carrier lifetime is found to be dominated by the spontaneous radiative process rather than the Auger process. The modal gain has a rather sensitive dependence on the number of quantum wells in the active region. The proposed laser is predicted to operate at 2.3 μm in the mid infrared at room temperature.

High glucose induces dysfunction and apoptosis in endothelial cells: is the effect of high glucose persistence more important than concentration?

Oxidative stress and inflammation are involved in the pathogenesis of diabetic endothelial dysfunction. Herein we reported the biological changes induced by hyperglycemia in human umbilical vein endothelial cells (HUVECs) and the potential underlying mechanisms sought to determine whether high glucose concentration or the persistence plays a key role in the development of vascular lesions. The HUVECs were exposed to various glucose concentrations (5, 15, 30, and 60 mmol/L of D-glucose supplemented), and several oxidative stress factors, such as NO, NOS, and ROS, and inflammatory signaling markers, such as TNF-α, TNFR, RIP, TRADD, TRAF-2 and NF-κB, were analyzed at various times (24, 48, 72, and 96 h). High glucose (HG) induced a transient increase of NO within 24 h and decreased afterwards, in accord with the expression of eNOS. HG also increased ROS and TNF-α production and activated the TNF-α-mediated signal transduction, decreasing cell viability and inducing apoptosis. However, 3 HG groups had similar effects on HUVECs with the increased duration of exposure, which resulted in the amplified oxidative and inflammatory damage. Taken together, these findings suggest that the HG persistence exacerbates oxidative stress and activates the inflammatory-mediated signaling pathways, inducing endothelial dysfunction and apoptosis, regardless of the concentration of HG. Our results provide the first evidence that HG persistence is more important than concentration in the progress of diabetic endothelial dysfunction.

Ablation of AMP-activated protein kinase alpha1 and alpha2 from mouse pancreatic beta cells and RIP2.Cre neurons suppresses insulin release in vivo

AIMS/HYPOTHESIS

AMP-activated protein kinase (AMPK) is an evolutionarily conserved enzyme and a target of glucose-lowering agents, including metformin. However, the precise role or roles of the enzyme in controlling insulin secretion remain uncertain.

METHODS

The catalytic alpha1 and alpha2 subunits of AMPK were ablated selectively in mouse pancreatic beta cells and hypothalamic neurons by breeding Ampkalpha1 [also known as Prkaa1]-knockout mice, bearing floxed Ampkalpha2 [also known as Prkaa2] alleles (Ampkalpha1 ( -/- ),alpha2( fl/fl ),), with mice expressing Cre recombinase under the rat insulin promoter (RIP2). RIP2 was used to express constitutively activated AMPK selectively in beta cells in transgenic mice. Food intake, body weight and urinary catecholamines were measured using metabolic cages. Glucose and insulin tolerance were determined after intraperitoneal injection. Beta cell mass and morphology were analysed by optical projection tomography and confocal immunofluorescence microscopy, respectively. Granule docking, insulin secretion, membrane potential and intracellular free Ca(2+) were measured with standard techniques.

RESULTS

Trigenic Ampkalpha1 ( -/- ),alpha2( fl/fl ) expressing Cre recombinase and lacking both AMPKalpha subunits in the beta cell, displayed normal body weight and increased insulin sensitivity, but were profoundly insulin-deficient. Secreted catecholamine levels were unchanged. Total beta cell mass was unaltered, while mean islet and beta cell volume were reduced. AMPK-deficient beta cells displayed normal glucose-induced changes in membrane potential and intracellular free Ca(2+), while granule docking and insulin secretion were enhanced. Conversely, betaAMPK transgenic mice were glucose-intolerant and displayed defective insulin secretion.

CONCLUSIONS/INTERPRETATION

Inhibition of AMPK activity within the beta cell is necessary, but not sufficient for stimulation of insulin secretion by glucose to occur. AMPK activation in extrapancreatic RIP2.Cre-expressing cells might also influence insulin secretion in vivo.

Effect of the ratios of diameter of silo to bead on the pressure screening in granular columns

We present the apparent mass measurements at the bottom of granular packings for different bead and silo sizes. The redirection parameter K in Janssen theory is found to increase with the ratios of the diameter of the silo to the bead. We attribute this feature to the friction between the beads and the confining wall of silo; it is the role of friction that leads to variations in the shielding of vertical stresses as well as pressure screening.

PACE+ Nutrition and Exercise Counseling for Obese Patients Based on Stage of Change at an Urban Primary Care Clinic

Background: Obesity screening and behavioral counseling for adults is recommended but rarely feasible to reduce the risk of developing cancer and many chronic diseases. We intiated obesity screening at an urban clinic and offered obese patients tailored counseling using PACE+, a validated tool designed for the primary care setting.

Aim: To evaluate obesity screening rates, readiness to change, preferences for change and change in BMI in patients counseled with PACE+.

Methods: Electronic medical record (EMR) review of patient data from May 2006 to March 2008. Analyses comparing stage of change to patient characteristics was conducted using the Cochran-Armitage Trend Test. Bivariate comparisons of the continuous items were analyzed using the Chi-square.

Results: Of 5,390 patients in the clinic practice, 2532 (47%) were obese, 2269 (42%) were normal or overweight, and 589 (11%) were not screened. PACE+ educators counseled 843 obese patients (33%) May 2006-March 2008. Mean age 50, mean BMI 39, 79% female and 98% African American. 31% of PACE+ participants had hypertension, diabetes mellitus and hyperlipidemia. Stage of change for exercise was most often contemplation (38%) and preparation (40%). The preferred activity was walking (62%). Most cited reasons to change behavior were to lower blood pressure, improve health, reduce weight, and increase energy. Most reported activity barriers were pain (20%), weather (13%), and time (10%). Most patients rated their stage of change for reducing calories as preparation (62%). Anticipated nutrition adherence barriers were “will-power,” cost, and time. Participants rated their self-confidence for activity and dietary changes highly. A trend to weight stabilization and weight loss was observed with follow-up.

Conclusion: Obesity screening and a structured low-intensity behavioral counseling by educators was feasible and reached 33% of obese patients in the practice. PACE+ evaluation in the EMR provides retrievable and measurable information about patient stage of change, preferences and perceived adherence barriers. This data can direct efforts to link community and personal resources to optimize behavioral and weight outcomes. Pain cited as an activity barrier by 20% needs further study.

High efficiency thin-film crystalline Si/Ge tandem solar cell

We propose and simulate a photovoltaic solar cell comprised of Si and Ge pn junctions in tandem. With an anti-reflection film at the front surface, we have shown that optimal solar cells favor a thin Si layer and a thick Ge layer with a thin tunnel hetero-diode placed in between. We predict efficiency ranging from 19% to 28% for AM1.5G solar irradiance concentrated from 1 approximately 1000 Suns for a cell with a total thickness approximately 100 microm.

Variation explained in mixed-model association mapping

Genomic mapping of complex traits across species demands integrating genetics and statistics. In particular, because it is easily interpreted, the R(2) statistic is commonly used in quantitative trait locus (QTL) mapping studies to measure the proportion of phenotypic variation explained by molecular markers. Mixed models with random polygenic effects have been used in complex trait dissection in different species. However, unlike fixed linear regression models, linear mixed models have no well-established R(2) statistic for assessing goodness-of-fit and prediction power. Our objectives were to assess the performance of several R(2)-like statistics for a linear mixed model in association mapping and to identify any such statistic that measures model-data agreement and provides an intuitive indication of QTL effect. Our results showed that the likelihood-ratio-based R(2) (R(LR)(2)) satisfies several critical requirements proposed for the R(2)-like statistic. As R(LR)(2) reduces to the regular R(2) for fixed models without random effects other than residual, it provides a general measure for the effect of QTL in mixed-model association mapping. Moreover, we found that R(LR)(2) can help explain the overlap between overall population structure modeled as fixed effects and relative kinship modeled though random effects. As both approaches are derived from molecular marker information and are not mutually exclusive, comparing R(LR)(2) values from different models provides a logical bridge between statistical analysis and underlying genetics of complex traits.

The relationship between Chinese construction workers' HIV/AIDS-related knowledge, attitudes and behaviour: a structural equation model

This study explored the relationship between human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS)-related knowledge, attitudes and behaviour in migrant urban construction workers using structural equation modelling (SEM). A cross-sectional study was conducted among 428 male subjects on three building sites in Shenyang City. The SEM model of HIV/AIDS-related knowledge, attitudes and behaviour was built using LISREL version 8.5 and it fitted the data well, as shown by an adjusted goodness of fit index of 0.82 and a root mean square error of approximation of 0.094. Knowledge of HIV/AIDS was closely correlated with attitudes and behaviour. Age was an important factor affecting HIV/AIDS-related knowledge, attitudes and behaviour. These findings suggest that increasing HIV/AIDS-related knowledge could improve the attitude and behaviour of migrant urban construction workers, enabling them to avoid high-risk behaviour that increases the spread of HIV/AIDS. Any intervention used will need to take the important factor of age into consideration.

Reliability and validity testing of the SF-36 questionnaire for the evaluation of the quality of life of Chinese urban construction workers

The quality of life (QOL) of the Chinese 'floating' migrant population is of growing concern. Urban construction workers are the main migrant population in China, but there is little published research on their QOL. The reliability and validity of the 36-Item Short Form Health Survey (SF-36) questionnaire were assessed by conducting a population-based study of migrant construction workers in Shenyang, China. Two construction sites were randomly selected from each of the five districts of Shenyang City and 1200 copies of the questionnaire were distributed to rurally-registered, non-Shenyang workers aged > or = 16 years at these sites. A total of 1125 questionnaires were evaluated. The overall Cronbach's alpha coefficient of the SF-36 questionnaire was 0.821 while the respective Cronbach's alpha coefficient for each dimension was > 0.70. Results showed that the SF-36 questionnaire demonstrated good reliability and validity, and that it can be used to measure QOL among Chinese migrant urban construction workers.

Evaluation of the association of CXCR4 expression with HER2 status or mTOR expression levels

e22192

Introduction: CXCR4 is a chemokine receptor that is linked to breast cancer metastasis. The putative mechanism involves activation of the HER-2/PI3K/PTEN/Akt/mammalian target of rapamycin (mTOR) pathway, resulting in enhanced synthesis of downstream proteins such as CXCR4 and eukaryotic initiation factor 4E (eIF4E). Overexpression of eIF4E has been shown to be an independent predictor of breast cancer outcome. Because HER-2/mTOR/CXCR4 pathway has mainly been observed in vitro, it deserves scrutiny to determine whether it is also seen in human breast cancers. We hypothesize that HER-2/mTOR axis is not significantly associated with CXCR4 regulation in human breast cancers. Method: 107 stages 1 - 3 breast cancers from a prospective breast cancer database were analyzed. Samples were quantified for mTOR, CXCR4, and eIF4E levels by Western Blot. mTOR, and eIF4E levels were quantified as fold-over benign breast tissues and CXCR4 levels were quantified as fold-over Hela cells. CXCR4 overexpression was defined as low (< 6.0 fold) or high (≥ 6.0 fold), and eIF4E expression level was separated into tertiles. Primary end points were cancer recurrence and death. Statistical analyses performed were independent student t-test, Spearman correlation, Kaplan-Meier survival curves, log-rank test, and Cox proportional hazard model. Results: All 59 HER-2 (-) and 48 HER-2 (+) breast cancer specimens overexpressed CXCR4 (mean=6.18 ±4.4), mTOR (mean=1.24 ±1.58), and eIF4E (mean=9.53 ±6.42). Unlike in vitro data, there was no difference in mean CXCR4 expression level between HER-2 (-) and HER-2 (+) tumors (mean=6.55, 5.72, respectively) (p=0.33). While mTOR correlated significantly with eIF4E level (p=0.0006, r = 0.34), it did not correlate with CXCR4 level (p=0.713, r=0.036). Only nodal status (p=0.04) and eIF4E level (p=0.03) were independent predictors of breast cancer death. Conclusions: We demonstrate that CXCR4 regulation in human breast cancers is more complex than previously thought. There was no correlation between mTOR and CXCR4 levels, nor was there a difference in mean CXCR4 overexpression levels between HER-2 (+) and HER-2 (-) tumors. Pathways regulating CXCR4 expression warrant further investigation.

No significant financial relationships to disclose.

QTL analyses of seed weight during the development of soybean (Glycine max L. Merr.)

At harvest traits such as seed weight are the sum of development and responses to stresses over the growing season and particularly during the reproductive phase of growth. The aim here was to measure quantitative trait loci (QTL) underlying the seed weight from early development to drying post harvest. One hundred forty-three F(5) derived recombinant inbred lines (RILs) developed from the cross of soybean cultivars 'Charleston' and 'Dongnong 594' were used for the analysis of QTL underlying mean 100-seed weight at six different developmental stages. QTL x Environment interactions (QE) were analyzed by a mixed genetic mode based on 3 years' data. At an experiment-wise threshold of a=0.05 and by single-point analysis 94 QTL unaffected by QE underlay the mean seed weight at different developmental stages. Sixty-eight QTL affected by QE that also underlay mean seed weight were identified. From the 162 QTL 42 could be located on 12 linkage groups by composite interval mapping (LOD>2.0). The numbers, locations and types of the QTL and the genetic effects were different at each developmental stage. On linkage group C2 the distantly linked QTL swC2-1, swC2-2 and swC2-3 each affected mean seed weight throughout the different developmental stages. The DNA markers linked to the QTL possessed potential for use in marker-assisted selection for soybean seed size. The identification of QTL with genetic main effects and QE interaction effects suggested that such interactions might significantly alter seed weight during seed development.

RNA interference-mediated silencing of the polo-like kinase 1 gene enhances chemosensitivity to gemcitabine in pancreatic adenocarcinoma cells

Gemcitabine is the first-line chemotherapeutic agent for advanced adenocarcinoma of the pancreas; however, chemoresistance to gemcitabine remains a major cause of failure for the clinical treatment of this disease. Polo-like kinase 1 (Plk-1) is highly expressed in pancreatic cancer cell lines and pancreatic tumour tissues, and is involved in a wide variety of cell cycle processes. Nevertheless, its biological role and implication for gemcitabine resistance are not clearly defined. In this study, we used RNA-interference (RNAi)-mediated depletion of Plk-1 to determine its potential for sensitizing pancreatic tumour cells to gemcitabine. We showed that the level of Plk-1 protein was correlated significantly with gemcitabine resistance in human pancreatic adenocarcinoma cells and that overexpression of Plk-1 reduced sensitivity to gemcitabine in these cells. In addition, small interfering RNA (siRNA)-mediated knockdown of Plk-1 caused cell cycle arrest at G2/M and the reduction of cellular proliferation. More importantly, the treatment of pancreatic cancer cells with Plk-1 siRNA followed by exposure to gemcitabine dramatically decreased cell viability and increased cellular apoptosis, as compared with treatment with either agent alone. These observations indicate that down-regulation of Plk-1 expression by RNAi enhances gemcitabine sensitivity and increases gemcitabine cytotoxicity in pancreatic tumour cells. This is the first demonstration that the combination of Plk-1 gene therapy and gemcitabine chemotherapy has synergistic anti-tumour activity against pancreatic carcinoma in vitro. This combination treatment warrants further investigation as an effective therapeutic regimen for patients with resistant pancreatic cancer and other tumours.

A statistical analysis on the removal of organic matter in subsurface flow constructed wetlands in the U.K

The performances of 98 subsurface flow constructed wetlands in the U.K. are analysed for the rates of organic matter removal from various wastewaters. The analyses of 78 subsurface horizontal flow wetlands are focused on deriving the value of rate constant K(BOD) in the Kickuth equation and evaluating the probability of meeting the target when the equation is used in design. The analyses of 20 vertical flow wetlands are focused on establishing the correlations between BOD (biochemical oxygen demand) removal rate and organic loading; an empirical relation has been developed to estimate the surface areas of the wetlands.

Thin-trimming of the scrotal reconstruction flap: long-term follow-up shows reversal of spermatogenesis arrest

OBJECTIVE

To explore a method to decrease the arrest of spermatogenesis in patients undergoing scrotum reconstruction with a flap.

METHODS

A follow-up study on a patient whose scrotum had been reconstructed with a flap revealed the arrest of spermatogenesis. The flap was trimmed thin on two occasions, and the composition of the seminal fluid was followed up.

RESULTS

The follow-up showed a decrease in the arrest of spermatogenesis after the flap was thin-trimmed.

CONCLUSIONS

Thin-trimming the reconstruction flap can decrease the degree of spermatogenesis arrest in patients who have received scrotum reconstruction by thick flap.