Food Cue Reactivity in Fasting and Non-Fasting Subjects

In the present study, psychophysiological food cue reactivity was studied in fasting and non-fasting subjects. It was expected that food related stimuli would elicit stronger responses than control (soap) stimuli and that responses to food stimuli would be particularly strong in fasting subjects. The results show that although the subjects' craving was larger during presentation of food cues than during control stimuli, the larger craving was not reflected in increased psychophysiological responsivity (heart rate; frequency of skin conductance (SC) fluctuations) or salivation. Subjects in the fasting condition had a lower baseline frequency of SC-fluctuations, and a trend towards lower heart rate, indicating decreased sympathetic tonic level. In comparison with non-fasting subjects, no specifically enlarged food cue reactivity was found in fasting subjects. It is proposed that future research into food cue reactivity should focus on the role of learning rather than deprivation.     

Encoding and retrieval of landmark‐related spatial cues during navigation: An fMRI study

To successfully navigate, humans can use different cues from their surroundings. Learning locations in an environment can be supported by parallel subsystems in the hippocampus and the striatum. We used fMRI to look at differences in the use of object‐related spatial cues while 47 participants actively navigated in an open‐field virtual environment. In each trial, participants navigated toward a target object. During encoding, three positional cues (columns) with directional cues (shadows) were available. During retrieval, the removed target had to be replaced while either two objects without shadows (objects trial) or one object with a shadow (shadow trial) were available. Participants were informed in blocks about which type of retrieval trial was most likely to occur, thereby modulating expectations of having to rely on a single landmark or on a configuration of landmarks. How the spatial learning systems in the hippocampus and caudate nucleus were involved in these landmark‐based encoding and retrieval processes were investigated. Landmark configurations can create a geometry similar to boundaries in an environment. It was found that the hippocampus was involved in encoding when relying on configurations of landmarks, whereas the caudate nucleus was involved in encoding when relying on single landmarks. This might suggest that the observed hippocampal activation for configurations of objects is linked to a spatial representation observed with environmental boundaries. Retrieval based on configurations of landmarks activated regions associated with the spatial updation of object locations for reorientation. When only a single landmark was available during retrieval, regions associated with updating the location of oneself were activated. There was also evidence that good between‐participant performance was predicted by right hippocampal activation. This study therefore sheds light on how the brain deals with changing demands on spatial processing related purely to landmarks. © 2014 Wiley Periodicals, Inc.     

Is Restaging with Chest and Abdominal CT Scan after Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer Necessary?

Background

There is no evidence regarding restaging of patients with locally advanced rectal cancer after a long course of neoadjuvant radiotherapy with or without chemotherapy. This study evaluated the value of restaging with chest and abdominal computed tomographic (CT) scan after radiotherapy.

Methods

Between January 2000 and December 2010, all newly diagnosed patients in our tertiary referral hospital, who underwent a long course of radiotherapy for locally advanced rectal cancer, were analyzed. Patients were only included if they had chest and abdominal imaging before and after radiotherapy treatment.

Results

A total of 153 patients who met the inclusion criteria and were treated with curative intent were included. A change in treatment strategy due to new findings on the CT scan after radiotherapy was observed in 18 (12 %) of 153 patients. Twelve patients (8 %) were spared rectal surgery due to progressive metastatic disease.

Conclusions

Restaging with a chest and abdominal CT scan after radiotherapy for locally advanced rectal cancer is advisable because additional findings may alter the treatment strategy.     

Non-invasive and minimally invasive staging of regional lymph nodes in penile cancer

Introduction  The management of the regional lymph nodes in penile cancer patients, particularly when these lymph nodes are impalpable, remains controversial. Prophylactic bilateral inguinal lymphadenectomy is associated with high morbidity and is often unnecessary. However, there is no non-invasive or minimally invasive staging technique that can determine the lymph node status of penile cancer patients with 100% accuracy. Methods  We reviewed the current literature to examine the role of non-invasive and minimally invasive techniques for staging regional lymph nodes in penile cancer with particular reference to clinically impalpable disease. Results  Cross-sectional imaging (un-enhanced CT and MRI) modalities have a role in the assessment of patients with palpable inguinal basins and in locating distant metastases, but are unreliable in staging impalpable regional lymph nodes. The spatial resolution of lymphotropic nanoparticle enhanced MRI (LNMRI) and positron emission tomography (PET)/CT are limited to several millimetres and so these modalities cannot reliably detect micro-metastases (<2 mm). Ultrasound (US) and fine-needle aspiration cytology (FNAC) are indicated in staging palpable inguinal basins but are unreliable in isolation in the assessment of impalpable lymph nodes. They are, however, useful as an adjunct to dynamic sentinel lymph node biopsy (DSLNB) in lowering false-negative rates. Conclusions  While we await staging modalities that can equal the results of DSLNB with fewer disadvantages, histological staging in the form of DSLNB remains the best minimally invasive staging modality we can offer at risk patients presenting with clinically node negative groins.