A magnetically actuated cellular strain assessment tool for quantitative analysis of strain induced cellular reorientation and actin alignment.

Commercially available cell strain tools, such as pneumatically actuated elastomer substrates, require special culture plates, pumps, and incubator setups. In this work, we present a magnetically actuated cellular strain assessment tool (MACSAT) that can be implemented using off-the-shelf components and conventional incubators. We determine the strain field on the MACSAT elastomer substrate using numerical models and experimental measurements and show that a specific region of the elastomer substrate undergoes a quasi-uniaxial 2D stretch, and that cells confined to this region of the MACSAT elastomer substrate undergo tensile, compressive, or zero axial strain depending on their angle of orientation. Using the MACSAT to apply cyclic strain on endothelial cells, we demonstrate that actin filaments within the cells reorient away from the stretching direction, towards the directions of minimum axial strain. We show that the final actin orientation angles in strained cells are spread over a region of compressive axial strain, confirming previous findings on the existence of a varied pre-tension in the actin filaments of the cytoskeleton. We also demonstrate that strained cells exhibit distinctly different values of actin alignment coherency compared to unstrained cells and therefore propose that this parameter, i.e., the coherency of actin alignment, can be used as a new readout to determine the occurrence/extent of actin alignment in cell strain experiments. The tools and methods demonstrated in this study are simple and accessible and can be easily replicated by other researchers to study the strain response of other adherent cells.

Magnetically actuated microstructured surfaces can actively modify cell migration behaviour.

We present a study on the application of magnetically actuated polymer micropillar surfaces in modifying the migration behaviour of cells. We show that micropillar surfaces actuated at a frequency of 1 Hz can cause more than a 5-fold decrease in cell migration rates compared to controls, whereas non-actuated micropillar surfaces cause no statistically significant alterations in cell migration rates. The effectiveness of the micropillar arrays in impeding cell migration depends on micropillar density and placement patterns, as well as the direction of micropillar actuation with respect to the direction of cell migration. Since the magnetic micropillar surfaces presented can be actuated remotely with small external magnetic fields, their integration with implants could provide new possibilities for in-vivo tissue engineering applications.

Prevalence of dyspepsia and its correlation with demographic factors and lifestyle in shiraz, southern iran.

BACKGROUND Dyspepsia is a common disorder that can present many clinical dilemmas in patient management. Although not life-threatening, the symptoms are long-lasting, interfere with daily activities and have a significant impact upon quality of life. The aim of this study was to determine prevalence of dyspepsia and its relationship with demographic and socioeconomic factors, and lifestyle in an apparently healthy population in Shiraz, southern Iran. METHODS In a population-based study, 1978 subjects aged 35 years or older were interviewed from April to September 2004. A questionnaire consisting of demographic factors, lifestyle data and gastrointestinal symptoms was completed for each participant. The validity and reliability of the questionnaire were determined. RESULTS The prevalence of dyspepsia was 29.9%. The dyspeptic patients were classified as having ulcer-like (27.9%), dysmotility-like (26.2%) or unspecified dyspepsia (45.9%). The prevalence was higher in females, water-pipe smokers, NSAIDs users, and in those with psychological distress, recurrent headache, anxiety, nightmares and past history of gastrointestinal disease. Dyspepsia had an inverse relationship with consumption of pickles, fruits and vegetables, and with duration of meal ingestion. Subjects with dyspepsia symptoms were more likely to restrict their diet, take herbal medicine, use over-the-counter drugs, consult with physicians and consume medication advised by their friends. CONCLUSION This study reveals that dyspepsia has a high prevalence in Shiraz, southern Iran and is associated with several demographic factors, lifestyle and health-seeking behavior.

Subjective lactose intolerance in apparently healthy adults in southern Iran: Is it related to irritable bowel syndrome?

BACKGROUND: The main symptoms of lactose intolerance are bloating, abdominal cramps, increased flatus and loose watery stools. These symptoms are similar to those of irritable bowel syndrome (IBS), which is a prevalent entity in the community. OBJECTIVE: As there was no data available on the prevalence of LI and the correlated factors, this study aimed to determine these correlations and their relation to IBS symptoms in an apparently healthy population in Shiraz, southern Iran. MATERIALS AND METHODS: A survey among 1,978 individuals older than 35 years was conducted in Shiraz, southern Iran, using a questionnaire that consisted of items regarding demographic data, life style, subjective gastrointestinal symptoms of LI and IBS symptoms according to ROME II criteria. RESULTS: A total of 562 subjects reported LI (28.41%). The prevalence was significantly higher in females, in subjects taking NSAIDs or acetaminophen and in cases reporting IBS symptoms. Subjects with LI avoided certain foods and drinks; and in order to relieve their symptoms, they used OTC drugs, herbal medicine or visited a physician. On the other hand, no relation was found between LI and age, smoking or the number of meals per day. CONCLUSIONS: Although we found that individuals with IBS had significantly more subjective LI than those without IBS, in the absence of documented lactose malabsorption, it is hard to tell whether the reported symptoms indeed are those of LI or simply those of IBS. So, a period of dairy product avoidance and/ or requesting a test for lactose malabsorption may be beneficial in this area.