Involvement of 5-HT3 and 5-HT4 receptors in colonic motor patterns in rats

BACKGROUND

Colonic migrating motor complexes in the rat constitute two distinct propulsive motor patterns, pan-colonic rhythmic long distance contractions (LDCs), and rhythmic propulsive motor complexes (RPMCs) occurring primarily in the mid/distal colon. Interstitial cells of Cajal govern their rhythmicity, but their occurrence is dependent on neural programs. Our aim was to investigate the involvement of 5-HT3 and 5-HT4 receptors in the generation and pharmacological control of the motor patterns.

METHODS

Effects of 5-HT-related drugs on colonic motor patterns were analyzed through spatio-temporal maps created from video recordings of whole organ motility.

KEY RESULTS

5-HT3 antagonists abolished RPMCs and LDCs. 5-HT4 agonists inhibited LDCs; they promoted RPMCs, which was blocked by the 5-HT4 antagonist GR 125487. 5-HT and the 5-HT3 agonist m-CPBG strongly inhibited LDCs and RPMCs.

CONCLUSIONS & INFERENCES

The generation of LDCs involves ongoing 5-HT release acting on 5-HT3 and 5-HT4 receptors. The spontaneous generation of RPMCs involves ongoing 5-HT release acting on 5-HT3 but not 5-HT4 receptors. Prucalopride and mosapride promote RPMCs, an effect that is inhibited by the 5-HT4 receptor antagonist GR 125487. A 5-HT3 agonist does not promote RPMCs. Segmentation, including a pattern of sequential segmental activity not previously described, can occur without significant involvement of 5-HT3 and 5-HT4 receptors. 5-HT and a 5-HT3 agonist are strongly inhibitory indicating that 5-HT receptors are present in inhibitory pathways which are normally not involved in the generation of spontaneous or distention-induced motor patterns.

Pre-Chemoradiotherapy FDG PET/CT cannot Identify Residual Metabolically-Active Volumes within Individual Esophageal Tumors

Objective

To study whether subvolumes with a high pre-chemoradiotherapy (CRT) FDG uptake could identify residual metabolically-active volumes (MAVs) post-CRT within individual esophageal tumors. Accurate identification will allow simultaneous integrated boost to these subvolumes at higher risk to improve clinical outcomes.

Methods

Twenty patients with esophageal cancer were treated with CRT plus surgery and underwent FDG PET/CT scans before and after CRT. The two scans were rigidly registered. Seven MAVs pre-CRT and four MAVs post-CRT within a tumor were defined with various SUV thresholds. The similarity and proximity between the MAVs pre-CRT and post-CRT were quantified with three metrics: fraction of post-CRT MAV included in pre-CRT MAV, volume overlap and centroid distance.

Results

Eight patients had no residual MAV. Six patients had local residual MAV (SUV ≥2.5 post-CRT) within or adjoining the original MAV (SUV ≥2.5 pre-CRT). On average, less than 65% of any post-CRT MAVs was included in any pre-CRT MAVs, with a low volume overlap <45%, and large centroid distance >8.6 mm. In general, subvolumes with higher FDG-uptake pre-CRT or post-CRT had lower volume overlap and larger centroid distance. Six patients had new distant MAVs that were determined to be inflammation from radiation therapy.

Conclusions

Pre-CRT PET/CT cannot reliably identify the residual MAVs within individual esophageal tumors. Simultaneous integrated boost to subvolumes with high FDG uptake pre-CRT may not be feasible.

Ibrutinib inhibits collagen-mediated but not ADP-mediated platelet aggregation

The BTK (Bruton's tyrosine kinase) inhibitor ibrutinib is associated with an increased risk of bleeding. A previous study reported defects in collagen- and adenosine diphosphate (ADP)-dependent platelet responses when ibrutinib was added ex vivo to patient samples. Whereas the collagen defect is expected given the central role of BTK in glycoprotein VI signaling, the ADP defect lacks a mechanistic explanation. In order to determine the real-life consequences of BTK platelet blockade, we performed light transmission aggregometry in 23 patients receiving ibrutinib treatment. All patients had reductions in collagen-mediated platelet aggregation, with a significant association between the degree of inhibition and the occurrence of clinical bleeding or bruising (P=0.044). This collagen defect was reversible on drug cessation. In contrast to the previous ex vivo report, we found no in vivo ADP defects in subjects receiving standard doses of ibrutinib. These results establish platelet light transmission aggregometry as a method for gauging, at least qualitatively, the severity of platelet impairment in patients receiving ibrutinib treatment.

Monte Carlo simulations of nanoscale focused neon ion beam sputtering of copper: elucidating resolution limits and sub-surface damage

A three dimensional Monte Carlo simulation program was developed to model physical sputtering and to emulate vias nanomachined by the gas field ion microscope. Experimental and simulation results of focused neon ion beam induced sputtering of copper are presented and compared to previously published experiments. The simulation elucidates the nanostructure evolution during the physical sputtering of high aspect ratio nanoscale features. Quantitative information such as the energy-dependent sputtering yields, dose dependent aspect ratios, and resolution-limiting effects are discussed. Furthermore, the nuclear energy loss and implant concentration beneath the etch front is correlated with the sub-surface damage revealed by transmission electron microscopy at different beam energies.

Evaluating the clinical relevance of codon 594 (g>a) polymorphism of estrogen receptor alpha in knee osteoarthritis

It has been reported that oestrogen receptor alpha (ER-α) polymorphisms are associated with knee osteoarthritis (OA). In this study, we assessed whether there was any association between the codon 594 (G>A) polymorphism in ER-α and radiographic features of OA or patient function. Radiographs, WOMAC score and patient reported time of symptom onset were assessed in 194 patients presenting for total knee replacement at Ramathibodi hospital over a one year period. ESR-1 genotyping was assessed. There were 107 (55.15%) patients with common homozygote (GG), 78 (40.20%) patients with heterozygote (GA) and nine (4.65%) patients with rare homozygote (AA). There was poor correlation (r = <0.2) between group difference in the radiographic parameters, time of onset of symptom , or in WOMAC scores. This polymorphism is not associated with the clinical features of knee osteoarthritis. The role of this polymorphism is unlikely then to be used as a biological marker predicting the progression of knee OA.

Large volume osteosarcomas of the femur treated with total femoral replacement

Patients with extensive malignancies involving the femur often require total femoral replacement when their limbs can be salvaged. Reported series are small and involve heterogeneity of tumours. We present nine patients with osteosarcomas of the femur treated at our institution between 2003 and 2010 with a mean follow-up of 27 (6 to 56) months. Their ages ranged from 9 to 17 (mean 14 years). They had large volume tumours (mean 911 cm3) and presented late with a mean of 5.5 months from the onset of symptoms to definitive treatment. All patients underwent resection and total femur replacement. Six patients have died and two are alive with good function at the time of this report. One was lost to follow-up. These patients require a high level of treatment care and have a guarded prognosis.

Extracellular vesicles from blood plasma: determination of their morphology, size, phenotype and concentration

BACKGROUND

Plasma and other body fluids contain membranous extracellular vesicles (EVs), which are considered to derive from activated or apoptotic cells. EVs participate in physiological and pathological processes and have potential applications in diagnostics or therapeutics. Knowledge on EVs is, however, limited, mainly due to their sub-micrometer size and to intrinsic limitations in methods applied for their characterization.

OBJECTIVES

Our aim was to provide a comprehensive description of EVs from plasma of healthy subjects.

METHODS

Cryo-transmission electron microscopy combined with receptor-specific gold labeling was used to reveal the morphology, size and phenotype of EVs. An original approach based on sedimentation on electron microscopy grids was developed for enumerating EVs. A correlation was performed between conventional flow cytometry and electron microscopy results.

RESULTS

We show that platelet-free plasma samples contain spherical EVs, 30 nm to 1 μm in diameter, tubular EVs, 1-5 μm long, and membrane fragments, 1-8 μm large. We show that only a minority of EVs expose the procoagulant lipid phosphatidylserine, in contrast to the classical theory of EV formation. In addition, the concentrations of the main EV sub-populations are determined after sedimentation on EM grids. Finally, we show that conventional flow cytometry, the main method of EV characterization, detects only about 1% of them.

CONCLUSION

This study brings novel insights on EVs from normal plasma and provides a reference for further studies of EVs in disease situations.

Screening for cardiovascular disease risk factors at baseline and post intervention among adults with intellectual disabilities in an urbanised Asian society

BACKGROUND

Adults with intellectual disabilities (ID) face significant barriers to screening participation. We determined predictors for regular cardiovascular health screening at baseline among adults with ID in Singapore, and evaluated the effectiveness of a 3-month screening intervention.

METHODS

The study population involved all adults with ID aged ≥40 years receiving services from the Movement for the Intellectually Disabled of Singapore (MINDS), the largest such provider in Singapore. Over 3 months in 2011, adult clients not screened regularly at baseline for hypertension, diabetes and dyslipidaemia were offered free and convenient blood pressure, fasting blood glucose and lipid testing; data on other cardiovascular disease risk factors were also collected. Chi-square and logistic regression identified predictors of regular screening at baseline.

RESULTS

Participation was 95.0% (227/239). At baseline, among adults with ID, 61.8% (118/191), 24.8% (52/210) and 18.2% (34/187) had gone for regular hypertension, diabetes and dyslipidaemia screening respectively; post intervention, rates rose to 96.9%, 89.5% and 88.8% respectively. Prevalence of cardiovascular disease risk factors (22.5% with hypertension, 10.6% with diabetes, 34.8% with dyslipidaemia, 10.7% obese and 90.6% lacking regular exercise) was high compared against the general population. While receiving residential services was associated with regular hypertension screening, receiving non-residential services and being independently mobile were associated with regular participation in fasting blood tests (all P < 0.05).

CONCLUSION

Cardiovascular disease risk factors are common among adults with ID and clinicians should proactively screen such populations. Provision of free and convenient screening for cardiovascular disease risk improved screening participation.

Neural correlates of the abolished self-referential memory effect in schizophrenia

BACKGROUND

The self-referential memory (SRM) effect refers to the phenomenon that stimuli processed with reference to the self are better remembered than those referenced to others. Studies have shown that schizophrenia patients do not have this memorial advantage for self-referenced information. The current study investigated the electrophysiological mechanism of the abolished SRM effect in schizophrenia.

METHOD

Twenty schizophrenia patients and 22 controls were recruited to complete an SRM task. We used a high-time resolution event-related potential (ERP) technique to analyze the electrophysiological differences between patients and controls during self- and other-reflection processing.

RESULTS

Behavior data indicated that healthy controls had a typical SRM bias that was absent in the schizophrenia patients. ERP comparison between groups showed that the schizophrenia patients presented smaller voltages in both self- and other-reflection conditions in the 160-260 ms (P2 component) and 800-1200 ms (positive slow wave) time windows over the pre/frontal cortex. Furthermore, the N2 amplitudes (270-380 ms) differed between self- and other-reflection conditions in patients but not in normal controls. More importantly, we found that the P3 amplitudes in the parietal cortex correlated significantly with the SRM bias score in the patients (r = -0.688).

CONCLUSIONS

These results provide comprehensive and direct electrophysiological evidence for self- and other-reflective dysfunction in schizophrenia patients and contribute to our understanding of the underlying neural substrates of the abolished SRM effect in schizophrenia.

Circulating microRNAs as potential non-invasive biomarkers for the early detection of hypertension-related stroke

Hypertension is one of the most important risk and modifiable factors for stroke. Crucial in managing the cerebrovascular damage caused by long-lasting and inadequately treated hypertension is not only lowering arterial blood pressure but also early predicting subtypes of hypertension-related stroke and applying more effective interventions. Accumulating evidence suggested that circulating microRNAs (miRNAs) could be developed as biomarkers for early recognition of the onset of a variety of diseases. The role of miRNAs has been extensively reviewed, involving cardiac hypertrophy, hypertensive heart failure, kidney failure and renal fibrosis. miRNA research in stroke is still in its infancy, although there are few literatures reviewing the role of miRNAs in the processes of hypertension-related stroke. This review summarizes current advances in miRNAs regulation of critical pathogenic process underlying hypertension, ischemic stroke and hemorrhagic stroke, and highlights the potential of using circulating miRNAs as noninvasive biomarkers for the early detection of hypertension-related stroke.

The epidemic of human papillomavirus and oropharyngeal cancer in a Canadian population

BACKGROUND

Sexually transmitted infection with the human papillomavirus (hpv) is responsible for a significant burden of human cancers involving the cervix, anogenital tract, and oropharynx. Studies in the United States and Europe have demonstrated an alarming increase in the frequency of hpv-positive oropharyngeal cancer, but the same direct evidence does not exist in Canada.

METHODS

Using the London Health Sciences Centre pathology database, we identified tonsillar cancers diagnosed between 1993 and 2011. Real-time polymerase chain reaction was then used on pre-treatment primary-site biopsy samples to test for dna from the high-risk hpv types 16 and 18. The study cohort was divided into three time periods: 1993-1999, 2000-2005, and 2006-2011.

RESULTS

Of 160 tumour samples identified, 91 (57%) were positive for hpv 16. The total number of tonsillar cancers significantly increased from 1993-1999 to 2006-2011 (32 vs. 68), and the proportion of cases that were hpv-positive substantially increased (25% vs. 62%, p < 0.002). Those changes were associated with a marked improvement in 5-year overall survival (39% in 1993-1999 vs. 84% in 2006-2011, p < 0.001). When all factors were included in a multivariable model, only hpv status predicted treatment outcome.

INTERPRETATION

The present study is the first to provide direct evidence that hpv-related oropharyngeal cancer is increasing in incidence in a Canadian population. Given the long lag time between hpv infection and clinically apparent malignancy, oropharyngeal cancer will be a significant clinical problem for the foreseeable future despite vaccination efforts.

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.

Investigation of perceived social support in mothers of infants hospitalized in neonatal Intensive Care Unit

PURPOSE

To identify the degree of perceived social support by mothers of infants hospitalized in neonatal intensive care unit (NICU) and to investigate effects depression and anxiety levels on the perceived social support.

METHOD

The study included 50 mothers of infants hospitalized in NICU. Demographic and clinical characteristics of the mothers were collected using a personal data form designed by the study researchers via face-to-face interviews. The Multidimensional Scale of Perceived Social Support Scale (MSPSS) was used to evaluate the degree of perceived social support by the mothers and Hospital Anxiety and Depression (HAD) Scale was used to assess their anxiety and depression levels.

RESULTS

The mean age of the mothers was 29.1 ± 4.2 years. There was a significant correlation between the scores of the anxiety and depression subscales (r=0.772; p<0.001), whereas these scores were not significantly correlated with MSPSS total score. The scores MSPSS subscales were significantly correlated with each other, as well as with MSPSS total score. Friend subscale score and depression subscale score were positively correlated with education level (r=0.295, p=0.038 and r=0.407, p=0.003, respectively). The family and spouse subscale scores and MSPSS total score were significantly higher assisted conception technique group compared with the spontaneous conception group (p=0.020, p=0.010 and p=0.016, respectively). The family and spouse subscale scores and MSPSS total score were significantly lower in the mothers with depression subscale score of ≥7 than in the mothers with depression subscale score of <7 (p=0.010, p=0.038 and p=0.018, respectively). In the linear regression model, only education level was found to be a significant factor affecting depression level (p=0.006).

CONCLUSION

The mothers of infants hospitalized in the NICU with higher education levels had higher depression level and perceived social support from friends. Informing the family members and providing psychological support independent from the duration of gestation are of paramount importance.

Running behind a tourist: leisure-related skin cancer prophylaxis

The most important risk factor in the development of skin cancer is exposure to ultraviolet (UV) radiation. Cumulative lifetime UV radiation exposure has been shown to be most important in the pathogenesis of squamous cell carcinoma, whereas intermittent high-dose UV radiation exposure in childhood and adolescence may be more important in the aetiology of basal cell carcinoma and cutaneous malignant melanoma. Using established methodology and best available estimates on UV-related mortality and morbidity, it has been estimated that annually around 1·5 million disability-adjusted life years are lost through excessive exposure to UV radiation. Skin cancer is a significant health problem and its burden is such that it causes the health system more to treat than any other forms of cancer. Prevention is the key action in managing skin cancer at a population level. Investment in prevention programmes such as SunSmart encourages protective behaviours that will reduce the human and financial costs of skin cancer.

Impact of FTO genotypes on BMI and weight in polycystic ovary syndrome: a systematic review and meta-analysis

AIMS/HYPOTHESIS

FTO gene single nucleotide polymorphisms (SNPs) have been shown to be associated with obesity-related traits and type 2 diabetes. Several small studies have suggested a greater than expected effect of the FTO rs9939609 SNP on weight in polycystic ovary syndrome (PCOS). We therefore aimed to examine the impact of FTO genotype on BMI and weight in PCOS.

METHODS

A systematic search of medical databases (PubMed, EMBASE and Cochrane CENTRAL) was conducted up to the end of April 2011. Seven studies describing eight distinct PCOS cohorts were retrieved; seven were genotyped for SNP rs9939609 and one for SNP rs1421085. The per allele effect on BMI and body weight increase was calculated and subjected to meta-analysis.

RESULTS

A total of 2,548 women with PCOS were included in the study; 762 were TT homozygotes, 1,253 had an AT/CT genotype, and 533 were AA/CC homozygotes. Each additional copy of the effect allele (A/C) increased the BMI by a mean of 0.19 z score units (95% CI 0.13, 0.24; p = 2.26 × 10(-11)) and body weight by a mean of 0.20 z score units (95% CI 0.14, 0.26; p = 1.02 × 10(-10)). This translated into an approximately 3.3 kg/m(2) increase in BMI and an approximately 9.6 kg gain in body weight between TT and AA/CC homozygotes. The association between FTO genotypes and BMI was stronger in the cohorts with PCOS than in the general female populations from large genome-wide association studies. Deviation from an additive genetic model was observed in heavier populations.

CONCLUSIONS/INTERPRETATION

The effect of FTO SNPs on obesity-related traits in PCOS seems to be more than two times greater than the effect found in large population-based studies. This suggests an interaction between FTO and the metabolic context or polygenic background of PCOS.

Prevalence of diabetes in patients admitted to a cancer hospital

Cancer rates are increased in people with diabetes. There is also recent evidence that outcomes from cancer treatment are worse in those with diabetes. There is a need to assess the prevalence of diabetes in cancer patients in order to tailor resources and improve clinical outcomes. This study examined the prevalence of diabetes and hyperglycaemia and specific referrals amongst hospitalised patients in a specialist cancer hospital.

In a cancer hospital 11% of in-patients had either identified diabetes or hyperglycaemia (random blood glucose >11mmol/l.) Consecutive referrals to a diabetes consultant confirmed that over half of patients had gastro-intestinal tract primary cancers, over 20% had poor glycaemic control whilst on steroids, and 18% had poor glycaemic control during artificial nutrition. Referrals came from both medical and surgical teams.

Thus diabetes and hyperglycaemia are common problems amongst in-patients with cancer, and these patients have complex diabetes requirement. Patients with cancer and diabetes need access to specialist diabetes care.

Apoptosis and autophagy have opposite roles on imatinib-induced K562 leukemia cell senescence

Imatinib, the anti-Abl tyrosine kinase inhibitor used as first-line therapy in chronic myeloid leukemia (CML), eliminates CML cells mainly by apoptosis and induces autophagy. Analysis of imatinib-treated K562 cells reveals a cell population with cell cycle arrest, p27 increase and senescence-associated beta galactosidase (SA-β-Gal) staining. Preventing apoptosis by caspase inhibition decreases annexin V-positive cells, caspase-3 cleavage and increases the SA-β-Gal-positive cell population. In addition, a concomitant increase of the cell cycle inhibitors p21 and p27 is detected emphasizing the senescent phenotype. Inhibition of apoptosis by targeting Bim expression or overexpression of Bcl2 potentiates senescence. The inhibition of autophagy by silencing the expression of the proteins ATG7 or Beclin-1 prevents the increase of SA-β-Gal staining in response to imatinib plus Z-Vad. In contrast, in apoptotic-deficient cells (Bim expression or overexpression of Bcl2), the inhibition of autophagy did not significantly modify the SA-β-Gal-positive cell population. Surprisingly, targeting autophagy by inhibiting ATG5 is accompanied by a strong SA-β-Gal staining, suggesting a specific inhibitory role on senescence. These results demonstrate that in addition to apoptosis and autophagy, imatinib induced senescence in K562 CML cells. Moreover, apoptosis is limiting the senescent response to imatinib, whereas autophagy seems to have an opposite role.

The presence of donor-specific antibodies in renal transplantation

Determining the presence of anti-HLA antibodies before transplantation is an important factor to prevent loss of function among renal transplantations. In addition, recent studies have shown that not only the pretransplantation existence of anti-HLA antibody but also posttransplantation donor-specific antibodies (DSA) and non-donor-specific antibodies are significantly associated with allograft rejection or loss of graft function. This study presented DSA among patients after renal transplantation together with graft function and survival.