Dissociating activity in the lateral intraparietal area from value using a visual foraging task

We make decisions about where to look approximately three times per second in normal viewing. It has been suggested that eye movements may be guided by activity in the lateral intraparietal area (LIP), which is thought to represent the relative value of objects in space. However, it is not clear how values for saccade goal selection are prioritized while free-viewing in a cluttered visual environment. To address this question, we compared the neural responses of LIP neurons in two subjects with their saccadic behavior and three estimates of stimulus value. These measures were extracted from the subjects' performance in a visual foraging task, in which we parametrically controlled the number of objects on the screen. We found that the firing rates of LIP neurons did not correlate well with the animals' behavior or any of our estimated measures of value. However, if the LIP activity was further normalized, it became highly correlated with the animals' decisions. These data suggest that LIP activity does not represent value in complex environments, but that the value can easily be extracted with one further step of processing. We propose that activity in LIP represents attentional priority and that the downstream normalization of this activity is an essential process in guiding action.     

Prevalence and pattern of antimicrobial resistance of Shigella species among patients with acute diarrhoea in Karaj,Tehran, Iran

The study was carried out to determine the prevalence and pattern of antimicrobial resistance of Shigella species among patients with acute diarrhoea in Karaj, Tehran, Iran. The study included all acute diarrhoea patients who visited the hospitals and treatment centres of Karaj during November 2001-October 2002. Of 734 stool samples collected from patients with acute diarrhoea and analyzed for Shigella spp., 123 (16.8%) yielded Shigella spp. (7.5% Shigella flexneri, 5.2% S. sonnei, 2.6% S. dysenteriae, and 1.5% S. boydii). Of the Shigella isolates, 90.8% were resistant to one or more antimicrobial agent(s), and 87.8% were multidrug resistant. The most common resistance was to tetracycline (73.5%), trimethoprim-sulphamethoxazole (70.4%), and amoxicillin-clavulanic acid (50.0%). Resistance to cefixime, ciprofloxacin, ceftriaxone, and nalidixic acid was observed in 6.1%, 3.1%, 2.0%, and 1.0% of the isolates respectively. These findings suggest that Shigella spp. may be an important aetiological agent of diarrhoea with a high rate of drug resistance in this region, which requires further study.     

Safety and Efficacy of Setarud (IMOD TM ) Among People Living with HIV/AIDS: A Review

The broad use of highly active anti-retroviral therapy (HAART), especially in developing world, has been associated with several problems such as lactic acidosis, lipodistrophy, pancreatitis, hyperlipidemia, insulin resistance and hepatotoxicity. Extensive use of HAART has also resulted in emergence of resistant HIV variants. Thereby, a pressing need for development of novel and cost-effective agents arises from these limitations. Setarud (IMODTM) is a safe, naturally- derived immunomodulator that was introduced for treatment of HIV patients in Iran. It is prepared as a mixture of herbal extracts including Tanacetum vulgare (tansy), Rosa canina and Urtica dioica (nettle) in addition to selenium, flavonoids and carotenes. Tanacetum vulgare may relieve anti-inflammatory symptoms and Rosa canina defers blood glucose and cholesterol elevation. Extracts from Urtica dioica may prevent maturation of myeloid dendritic cells and reduce T cell responses. A significant rise of CD4 count was observed in HIV patients treated by IMODTM in clinical trial phases, which could be explained by its immunomodulatory effects. Anti-oxidative activity of compounds in IMODTM might play a role in the clinical outcomes of patients treated with this drug. Moreover, IMODTM may show improving activity upon lipid profile and liver metabolism. According to studies on IMODTM, it seems that IMODTM has minor side effects. IMODTM with international publication number WO 2007/087825 A1 is an herbal extract which includes Rosa canina, Urtica dioica, Tanacetum vulgare, and selenium comprising a treatment by pulsed electromagnetic field of high frequency and is useful in treatment of HIV infection and AIDS.     

A correlative study comparing current different methods of calculating left ventricular ejection fraction

BACKGROUND: Left ventricular ejection fraction (EF) is a major determinant of survival in patients with coronary artery disease (CAD). Comparative accuracy of numerous modalities in calculating EF is not well investigated. METHOD: We compared EF as calculated by rest and post-stress Cedars automated quantitative gated SPECT (AQGS), rest and post-stress semi-automatically processed gated SPECT (MQGS), echocardiography and contrast ventriculography (LVG) to those determined by rest and post-stress cavity-to-myocardium ratio (CMR) in 109 patients. Gated SPECT was performed based on a 2-day protocol using Tc-MIBI. RESULTS: Mean EF in LVG, echo, post-stress CMR, rest CMR, post-stress AQGS, rest AQGS, post-stress MQGS and rest MQGS were 41.8%+/-12.1, 44.8%+/-11.8, 38.1%+/-10.7, 35.7%+/-12.1, 44.5%+/-15.1, 46.9%+/-14.7, 40.1%+/-14.3 and 43.5%+/-14.3 respectively. Although significant differences were observed between some of these methods, good and excellent linear correlations were present among values (all Pearson correlations >0.63). Considering LVG as the 'gold standard', we defined two groups: EF <35% (class 1) and >35% (class 2). Discriminant analysis showed that SPECT has the ability to predict patients' classes. In 4/18 of patients with normal SPECT (on both visual and quantitative analyses, SSS <4), EF on QGS showed a significant decrease on post-stress compared with rest. CONCLUSION: There is a good correlation in calculating EF by LVG, QGS and echocardiography, regardless of EF value. Whenever QGS is impossible, CMR is a reliable indirect indicator of EF. Gating of both phases (and when impossible, CMR of both phases) has an additional value in diagnosis of CAD.     

A pure salience response in posterior parietal cortex

When exploring a visual scene, some objects perceptually popout because of a difference of color, shape, or size. This bottom-up information is an important part of many models describing the allocation of visual attention. It has been hypothesized that the lateral intraparietal area (LIP) acts as a "priority map," integrating bottom-up and top-down information to guide the allocation of attention. Despite a large literature describing top-down influences in LIP, the presence of a pure salience response to a salient stimulus defined by its static features alone has not been reported. We compared LIP responses with colored salient stimuli and distractors in a passive fixation task. Many LIP neurons responded preferentially to 1 of the 2 colored stimuli, yet the mean responses to the salient stimuli were significantly higher than to distractors, independent of the features of the stimuli. These enhanced responses were significant within 75 ms, and the mean responses to salient and distractor stimuli were tightly correlated, suggesting a simple gain control. We propose that a pure salience signal rapidly appears in LIP by collating salience signals from earlier visual areas. This contributes to the creation of a priority map, which is used to guide attention and saccades.     

The prevalence and significance of increased gastric wall radiotracer uptake in sestamibi myocardial perfusion SPECT

Background: Limited available data indicate that a specific pattern of increased gastric wall radiotracer uptake is associated with dyspepsia. Our purpose was to evaluate the frequency of this finding and its relation with dyspeptic evidences. Method: 1056 consecutive outpatients referred for myocardial perfusion SPECT were interviewed concerning the dyspeptic symptoms, current gastric medications and previous gastroduodenal interventions. The intensity of gastric wall activity was graded qualitatively as G1 or hyperactive gastric wall (equivalent to the patient’s heart activity) and G2 (less than heart activity). Results: The pattern of gastric wall hyperactivity was identified in 1.9% of patients. Dyspeptic symptoms were present in 80 and 18.6% of G1 and G2 patients, respectively (p<0.001). The dyspeptic symptoms were classified as ulcer-like in 37.5%, dysmotility-like in 43.75% and GERD-like in 18.75% of the dyspeptic G1 patients. Considering the classification of dyspepsia, there was no significant difference between the dyspeptic patients of groups. The history of previous gastroduodenal interventions and current use of gastric medications was significantly higher among G1 patients. Conclusion: The infrequent pattern of gastric wall hyperactivity could be clinically important and can identify a category of patients, who require additional diagnostic gastrointestinal investigation to specify another possible noncardiac origin of complaints.