S‐Gal®, A novel 1H MRI reporter for β‐galactosidase

Reporter genes and associated enzyme activity are becoming increasingly significant for research in vivo. The lacZ gene and β‐galactosidase (β‐gal) expression have long been exploited as reporters of biologic manipulation at the molecular level, and a noninvasive detection strategy based on proton MRI is particularly attractive. 3,4‐Cyclohexenoesculetin β‐D‐galactopyranoside (S‐Gal®) is a commercial histologic stain, which forms a black precipitate in the presence of β‐gal and ferric ions, suggesting potential detectability by MRI. Generation of the precipitate is now shown to cause strong T₂* relaxation, revealing β‐gal activity. A series of tests with the enzyme in vitro and with tumor cells shows that this approach can be used as an assay for β‐gal activity. Proof of principle is shown in human breast tumor xenografts in mice. Upon direct injection of a mixture of 3,4‐cyclohexenoesculetin β‐D‐galactopyranoside and ferric ammonium citrate, intense contrast was observed immediately in MCF7‐lacZ tumors, but not in wild‐type tumors. 3,4‐Cyclohexenoesculetin β‐D‐galactopyranoside activation in combination with ferric ions introduces a novel approach for assaying enzyme activity by MRI in vivo. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

Influence of Age on Linear and Nonlinear Measures of Autonomic Cardiovascular Modulation

Background: Age has been identified as an independent risk factor for cardiovascular diseases. In addition, autonomic imbalance toward sympathetic preponderance has been shown to facilitate the occurrence of heart disease. Here, we aimed to assess autonomic modulation of cardiovascular parameters during normal ageing applying well‐established linear and novel nonlinear parameters. Methods: Linear and nonlinear measures of heart rate variability and complexity as well as measures of QT interval variability and baroreflex sensitivity were obtained from a total of 131 healthy, medication‐free participants from a continuous age range between 20 and 90 years, who were allocated to three different age groups. Results: Heart rate variability and complexity significantly decreased with age, while regularity of heart rate time series increased. In addition, QT interval variability linearly increased with age, while baroreflex sensitivity showed a pronounced decrease. Overall, concerning effects of ageing, linear and nonlinear parameters showed equal differentiation between groups. Conclusion: These data indicate a shift of autonomic balance toward sympathetic predominance in higher age groups, limiting the reactiveness of the cardiovascular system to adjust to different demands and increasing the risk for developing tachyarrhythmias. Ann Noninvasive Electrocardiol 2010;15(2):165–174     

Vascular imaging of solid tumors in rats with a radioactive arsenic-labeled antibody that binds exposed phosphatidylserine.

PURPOSE: We recently reported that anionic phospholipids, principally phosphatidylserine, become exposed on the external surface of vascular endothelial cells in tumors, probably in response to oxidative stresses present in the tumor microenvironment. In the present study, we tested the hypothesis that a chimeric monoclonal antibody that binds phosphatidylserine could be labeled with radioactive arsenic isotopes and used for molecular imaging of solid tumors in rats. EXPERIMENTAL DESIGN: Bavituximab was labeled with (74)As (beta(+), T(1/2) 17.8 days) or (77)As (beta(-), T(1/2) 1.6 days) using a novel procedure. The radionuclides of arsenic were selected because their long half-lives are consistent with the long biological half lives of antibodies in vivo and because their chemistry permits stable attachment to antibodies. The radiolabeled antibodies were tested for the ability to image subcutaneous Dunning prostate R3227-AT1 tumors in rats. RESULTS: Clear images of the tumors were obtained using planar gamma-scintigraphy and positron emission tomography. Biodistribution studies confirmed the specific localization of bavituximab to the tumors. The tumor-to-liver ratio 72 h after injection was 22 for bavituximab compared with 1.5 for an isotype-matched control chimeric antibody of irrelevant specificity. Immunohistochemical studies showed that the bavituximab was labeling the tumor vascular endothelium. CONCLUSIONS: These results show that radioarsenic-labeled bavituximab has potential as a new tool for imaging the vasculature of solid tumors.     

Inhibition of Jun NH2-terminal kinases suppresses the growth of experimental head and neck squamous cell carcinoma.

PURPOSE: This study was carried out to investigate whether c-Jun NH2-terminal kinases (JNK) are potential targets for treating head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN: JNK activity was first evaluated in 20 paired samples of human HNSCC. The antitumor activity of SP600125, a reversible nonselective ATP-competitive inhibitor of JNKs, was then investigated both in an HNSCC xenograft model and in vitro using immunohistochemistry, immunoblotting, enzyme immunoassay, flow cytometry, and a Matrigel assay of capillary tube formation. Complementary studies were carried out using small interfering RNA to JNK1/2. RESULTS: JNK activity was increased in human HNSCC compared with normal-appearing epithelium. Treatment of mice bearing HNSCC xenografts with SP600125 resulted in >60% inhibition of tumor growth relative to vehicle-treated animals. Inhibition of tumor growth was associated with significant reductions in both cell proliferation and microvessel density. SP600125 inhibited tumor cell proliferation by causing delays in both the S and G2-M phases of the cell cycle. Inhibition of angiogenesis seemed to reflect effects on both tumor and endothelial cells. The JNK inhibitor suppressed the production of vascular endothelial growth factor and interleukin-8 by tumor cells and also inhibited endothelial cell proliferation and capillary tube formation. Reduced amounts and phosphorylation of epidermal growth factor receptor were found in tumor cells after treatment with SP600125. Small interfering RNA-mediated suppression of JNK1/2 led to reduced tumor cell proliferation and decreased levels of epidermal growth factor receptor, vascular endothelial growth factor, and interleukin-8. CONCLUSIONS: JNK activity is commonly increased in HNSCC. Our preclinical results provide a rationale for evaluating JNK inhibition as an approach to treating HNSCC.     

The impact of maternal experience of violence and common mental disorders on neonatal outcomes: a survey of adolescent mothers in Sao Paulo,Brazil

Background  

Both violence and depression during pregnancy have been linked to adverse neonatal outcomes, particularly low birth weight. The aim of this study was to investigate the independent and interactive effects of these maternal exposures upon neonatal outcomes among pregnant adolescents in a disadvantaged population from Sao Paulo, Brazil.     

Chronic subdural hematoma complicating arachnoid cyst secondary to soccer-related head injury: case report

OBJECTIVE AND IMPORTANCE: Soccer has become a popular sport, with more than 200 million Federation International Football Association-registered soccer players worldwide and 16 million participants in the United States. The risk of sustaining a significant head injury from a strike to a soccer ball with the head is unknown, but it may be increased with the presence of an underlying congenital arachnoid cyst. CLINICAL PRESENTATION: We describe the case of a 16-year-old female patient who sustained a large chronic and subacute subdural hematoma without a loss of consciousness from being struck on the head by a soccer ball. Because of the large size of the hematoma and her contralateral symptoms, surgery was performed. INTERVENTION: A temporal craniotomy for evacuation of a large chronic and subacute subdural hematoma with removal and fenestration of the arachnoid cyst resulted in resolution of her symptoms. Rigid craniotomy fixation of this small operative flap should allow the patient to return to soccer participation in the future. CONCLUSION: Although many may not consider soccer a contact sport, recent epidemiological data suggest that it is a common cause of sports-related concussion. In addition, as our case report demonstrates, there is a risk of significant intracranial injury and hematoma formation subsequent to a strike on the head by a soccer ball, and arachnoid cysts may contribute an additional risk of head injury.     

Hyperhomocysteinemia,and low intakes of folic acid and vitamin B12 in urban North India

Summary Background and Aim An adverse coronary risk profile has been reported amongst rural-to-urban migrant population living in urban slums undergoing stressful socio-economic transition. These individuals are likely to have low intakes of folic acid and vitamin B12, which may have an adverse impact on serum levels of homocysteine (Hcy). To test this hypothesis, we studied serum levels of Hcy in subjects living in an urban slum of North India and healthy subjects from urban non-slum area. Methods Group I consisted of 46 subjects (22 males and 24 females) living in an urban slum, while group II consisted of healthy subjects (n = 26, 13 males and 13 females) living in the adjacent non-slum area. Anthropometric measurements, biochemical profile (fasting blood glucose, total cholesterol, serum triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol) and fasting serum levels of Hcy were measured. Dietary intakes of folic acid, vitamin B12, vitamin B1, and iron were calculated by the 24-hour dietary recall method. Serum levels of Hcy were correlated with dietary intakes of nutrients, anthropometry, and metabolic variables. Results Sex-adjusted serum levels of Hcy in mmol/L (Mean ± SD) were high, though statistically comparable, in both the groups (group I: 20.8 ± 5.9 and group II: 23.2 ± 5.9). Overall, higher than normal serum levels of Hcy (> 15 μmol/L) were recorded in 84 % of the subjects. A substantial proportion of subjects in both groups had daily nutrient intakes below that recommended for the Asian Indian population (folic acid: 93.4 % in group I and 96.7 % in group II, vitamin B12: 76.1 % in group I and 88.4 % in group II). However, between the two groups, average daily dietary intakes of both the nutrients were statistically comparable. As compared to non-vegetarians, vegetarians showed lower intakes of folic acid (p < 0.01) and vitamin B12 (p < 0.01) in both groups. On multivariate linear regression analysis with serum Hcy as the response variable and vegetarian/non-vegetarian status and sex (male/female) as predictor variables, higher serum levels of Hcy were observed in vegetarians vs non-vegetarians (β = 4.6, p < 0.05) and males vs females (β = 5.3, p < 0.01). Conclusions Low intakes of folic acid and vitamin B12, and hyperhomocysteinemia, in both the healthy population living in urban slums and adjacent urban non-slum areas, are important observations for the prevention of nutritional and cardiovascular diseases in the Indian subcontinent. Received: 30 October 2001, Accepted: 14 January 2002     

Effect of nortriptyline and paroxetine on measures of chaos of heart rate time series in patients with panic disorder

Tricyclic antidepressants have notable cardiac side effects, and this issue has become important due to the recent reports of increased cardiovascular mortality in patients with depression and anxiety. Several previous studies indicate that serotonin reuptake inhibitors (SRIs) do not appear to have such adverse effects. Apart from the effects of these drugs on routine 12-lead ECG, the effects on beat-to-beat heart rate (HR) and QT interval time series provide more information on the side effects related to cardiac autonomic function. In this study, we evaluated the effects of two antidepressants, nortriptyline (n=13), a tricyclic, and paroxetine (n=16), an SRI inhibitor, on HR variability in patients with panic disorder, using a measure of chaos, the largest Lyapunov exponent (LLE) using pre- and posttreatment HR time series. Our results show that nortriptyline is associated with a decrease in LLE of high frequency (HF: 0.15–0.5 Hz) filtered series, which is most likely due to its anticholinergic effect, while paroxetine had no such effect. Paroxetine significantly decreased sympathovagal ratios as measured by a decrease in LLE of LF/HF. These results suggest that paroxetine appears to be safer in regards to cardiovascular effects compared to nortriptyline in this group of patients.     

Development of transferable skills during short special study modules: students' self-appraisal

Special study modules (SSMs) were introduced into the Leeds undergraduate medical curriculum following recommendations by the General Medical Council (GMC). The main rationale behind such project work is to enable students to develop the skills and attitudes necessary for future self-directed learning along with the knowledge required to practise as competent doctors. At the University of Leeds, the students complete SSM monitoring forms for each SSM in the fourth year, aimed at allowing students to self-evaluate the SSMs. In addition, it provides useful feedback from the students on the themes of the projects as well as on the transferable skills developed by the students during their individual SSMs. The aim of the study was to identify the themes pursued in each project, look at the transferable skills developed and evaluate the differences or similarities between the type of project pursued and the themes and skills identified in the different specialities. A total of 181 monitoring forms of fourth-year students were analysed for the themes and the transferable skills identified. There were 55 students each in Obstetrics and Gynaecology and Paediatrics and 50 students each in Psychiatry and General Practice/Public Health. The results from the four specialities were compared for themes and skills identified. Overall, health and prevention was the commonest theme identified followed by communication skills (64.4% and 62.7% respectively). All transferable skills were well represented in the different specialities with information gathering and learning/organizational skills identified by most students as the major component. The feedback from the students is positive in terms of a wide range of transferable skills developed and most of the themes identified by the GMC are being pursued.