Modes of Disintegration of Solid Foods in Simulated Gastric Environment

A model stomach system was used to investigate disintegration of various foods in simulated gastric environment. Food disintegration modes and typical disintegration profiles are summarized in this paper. Mechanisms contributing to the disintegration kinetics of different foods were investigated as related to acidity, temperature, and enzymatic effect on the texture and changes in microstructure. Food disintegration was dominated by either fragmentation or erosion, depending on the physical forces acting on food and the cohesive force within the food matrix. The internal cohesive forces changed during digestion as a result of water penetration and acidic and enzymatic hydrolysis. When erosion was dominant, the disintegration data (weight retention vs. disintegration time) may be expressed with exponential, sigmoidal, and delayed-sigmoidal profiles. The different profiles are the result of competition among the rates of water absorption, texture softening, and erosion. A linear-exponential equation was used to describe the different disintegration curves with good fit. Acidity and temperature of gastric juice showed a synergistic effect on carrot softening, while pepsin was the key factor in disintegrating high-protein foods. A study of the change of carrot microstructure during digestion indicated that degradation of the pectin and cell wall was responsible for texture softening that contributed to the sigmoidal profile of carrot disintegration

Digestion of Raw and Roasted Almonds in Simulated Gastric Environment

Knowledge of digestion kinetics of solid foods in human stomach, as affected by food processing methods, is critical in establishing processing conditions at the manufacturing stage to achieve desirable release of nutrients in the gastrointestinal tract. The objective of this study was to investigate how roasting affected disintegration and solid release properties of almond in simulated gastric environment. In vitro trials were performed for raw and roasted almonds by using static soaking method and a model stomach system. The changes in sample weight, dry mass, and moisture during the trials were determined. Both compression and penetration tests were used to investigate the texture of almonds with a focus on the influence of absorption of gastric juice. Light microscopy and transmission electronic microscopy were used to study the change in microstructure of the raw and roasted almonds after simulated digestion. The results suggested that the slow disintegration rate and the high amount of swelling of the almonds in the stomach may contribute to their high satiety property. Roasting significantly improved the disintegration rates of almonds and increased loss of solids during simulated digestion, which is well correlated with the decrease in the rigidity of almond samples after absorbing gastric juice. Microstructure of digested almonds showed breakage and breach of cell walls due to acid hydrolysis. Intercellular and intracellular channels formed in almonds during roasting are important for penetration of gastric juice that may facilitate an effective digestion

Attenuation of N2 amplitude of laser-evoked potentials by theta burst stimulation of primary somatosensory cortex

Theta burst stimulation (TBS) is a special repetitive transcranial magnetic stimulation (rTMS) paradigm, where bursts of low-intensity stimuli are applied in the theta frequency. The aim of this study was to investigate the effect of neuronavigated TBS over primary somatosensory cortex (SI) on laser-evoked potentials (LEPs) and acute pain perception induced with Tm : YAG laser stimulation. The amplitude changes of the N1, N2, and P2 components of LEPs and related subjective pain rating scores of 12 healthy subjects were analyzed prior to and following continuous TBS (cTBS), intermittent TBS (iTBS), intermediate TBS (imTBS), and sham stimulation. Our results demonstrate that all active TBS paradigms significantly diminished the amplitude of the N2 component, when the hand contralateral to the site of TBS was laser-stimulated. Sham stimulation condition had no significant effect. The subjective pain perception also decreased during the experimental sessions, but did not differ significantly from the sham stimulation condition. The main finding of our study is that TBS over SI diminished the amplitude of the N2 component evoked from the contralateral side without any significant analgesic effects. Furthermore, imTBS produced responses similar to those observed by other forms of TBS induced excitability changes in the SI

Association of narcolepsy-cataplexy with HLA-DRB1 and DQB1 in Mexican patients: A relationship between HLA and gender is suggested

<p>Abstract</p> <p>Background</p> <p>Narcolepsy-cataplexy is characterized by excessive daytime sleepiness with recurrent episodes of irresistible sleep, cataplexy, hallucinations and sleep paralysis. Its aetiology is unknown, but it is positively associated with the human leukocyte antigens (HLA) in all studied populations. The purpose of the present study was to investigate the association of HLA class II <it>DRB1</it>/<it>DQB1 </it>alleles with narcolepsy-cataplexy in Mexican Mestizo patients.</p> <p>Methods</p> <p>This is a case-control study of consecutive patients and ethnically matched controls. We included 32 patients diagnosed with typical narcolepsy-cataplexy, of the National Institute of Neurology, of the Institute of Psychiatry and at the Center of Narcolepsy at Stanford University. As healthy controls, 203 Mexican Mestizos were included. <it>DRB1 </it>alleles were identified using sequence based typing. A PCR-SSOP reverse dot blot was used for <it>DQB1 </it>typing. Allele frequency was calculated by direct counting and the significance of the differences was assessed using the Yates Chi square. Odds ratio and confidence intervals were evaluated.</p> <p>Results</p> <p>HLA-<it>DRB1</it>*1501 (OR = 8.2; pc < 0.0001) and <it>DQB1</it>*0602 (OR = 8.4; pc < 0.0001) were found positively associated with narcolepsy. When deleting <it>DQB1</it>*0602+ patients from the analysis, <it>DQB1</it>*0301 was also found increased (OR = 2.7; p = 0.035; pc = NS). <it>DQB1</it>*0602/<it>DQB1</it>*0301 genotype was present in 15.6% of the cases (OR = 11.5; p = 0.00035), conferring a high risk. <it>DRB1</it>*0407 (OR = 0.2; p = 0.016 pc = NS) and <it>DQB1</it>*0302(OR = 0.4; p = 0.017, pc = NS) were found decreased in the patients. The gender stratification analysis showed a higher risk in females carrying <it>DRB1</it>*1501 (OR = 15.8, pc < 0.0001) and <it>DQB1</it>*0602 (OR = 19.8, pc < 0.0001) than in males (OR = 5.0 for both alleles; p = 0.012, pc = NS for <it>DRB1 </it>& p = 0.0012, pc = 0.017 for <it>DQB1</it>). The susceptibility alleles found in Mexicans with narcolepsy are also present in Japanese and Caucasians; <it>DRB1</it>*04 linked protection has also been shown in Koreans. A stronger HLA association is suggested in females, in accordance with the sexual dimorphism claimed previously.</p> <p>Conclusion</p> <p>This knowledge may contribute to a better understanding of the disease pathogenesis in different populations. The evaluation of the risk to develop narcolepsy-cataplexy in carriers of the described alleles/genotypes may also be possible. A larger sample should be analysed in Mexican and in other Hispanic patients to confirm these results.</p

Why Self-Induced Pain Feels Less Painful than Externally Generated Pain: Distinct Brain Activation Patterns in Self- and Externally Generated Pain

Voluntary movement generally inhibits sensory systems. However, it is not clear how such movement influences pain. In the present study, subjects actively or passively experienced mechanical pain or pressure during functional MRI scanning. Pain and pressure were induced using two modified grip strengthener rings, each twined with four crystal bead strings, with polyhedral beads to induce pain, or spherical beads to induce pressure. Subjects held one ring in the left hand and were either asked to squeeze their left hand with their right hand (i.e., active pain or pressure), or to have their left hand squeezed by the experimenter (i.e., passive pain or pressure). Subjects rated the intensity and unpleasantness of the pain sensation lower in the active procedure than in the passive one. Correspondingly, pain-related brain areas were inhibited in the case of self-generated pain, including the primary somatosensory cortex (SI), anterior cingulate cortex (ACC), and the thalamus. These results suggest that active movement behaviorally inhibits concomitant mechanical pain, accompanied by an inhibition of pain response in pain-related brain areas such as the SI cortex. This might be part of the mechanisms underlying the kinesitherapy for pain treatment

Increased Immune Complexes of Hypocretin Autoantibodies in Narcolepsy

International audienceBACKGROUND: Hypocretin peptides participate in the regulation of sleep-wake cycle while deficiency in hypocretin signaling and loss of hypocretin neurons are causative for narcolepsy-cataplexy. However, the mechanism responsible for alteration of the hypocretin system in narcolepsy-cataplexy and its relevance to other central hypersomnias remain unknown. Here we studied whether central hypersomnias can be associated with autoantibodies reacting with hypocretin-1 peptide present as immune complexes. METHODOLOGY: Serum levels of free and dissociated (total) autoantibodies reacting with hypocretin-1 peptide were measured by enzyme-linked immunosorbent assay and analyzed with regard to clinical parameters in 82 subjects with narcolepsy-cataplexy, narcolepsy without cataplexy or idiopathic hypersomnia and were compared to 25 healthy controls. PRINCIPAL FINDINGS: Serum levels of total but not free IgG autoantibodies against hypocretin-1 were increased in narcolepsy-cataplexy. Increased levels of complexed IgG autoantibodies against hypocretin-1 were found in all patients groups with a further increase in narcolepsy-cataplexy. Levels of total IgM hypocretin-1 autoantibodies were also elevated in all groups of patients. Increased levels of anti-idiotypic IgM autoantibodies reacting with hypocretin-1 IgG autoantibodies affinity purified from sera of subjects with narcolepsy-cataplexy were found in all three groups of patients. Disease duration correlated negatively with serum levels of hypocretin-1 IgG and IgM autoantibodies and with anti-idiotypic IgM autoantibodies. CONCLUSION: Central hypersomnias and particularly narcolepsy-cataplexy are characterized by higher serum levels of autoantibodies directed against hypocretin-1 which are present as immune complexes most likely with anti-idiotypic autoantibodies suggesting their relevance to the mechanism of sleep-wake cycle regulation

Endpoints in pediatric pain studies

Assessing pain intensity in (preverbal) children is more difficult than in adults. Tools to measure pain are being used as primary endpoints [e.g., pain intensity, time to first (rescue) analgesia, total analgesic consumption, adverse effects, and long-term effects] in studies on the effects of analgesic drugs. Here, we review current and promising new endpoints used in pediatric pain assessment studies

Effect of an education programme for patients with osteoarthritis in primary care - a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Osteoarthritis (OA) is a degenerative disease, considered to be one of the major public health problems. Research suggests that patient education is feasible and valuable for achieving improvements in quality of life, in function, well-being and improved coping. Since 1994, Primary Health Care in Malmö has used a patient education programme directed towards OA. The aim of this study was to evaluate the effects of this education programme for patients with OA in primary health care in terms of self-efficacy, function and self-perceived health.</p> <p>Method</p> <p>The study was a single-blind, randomized controlled trial (RCT) in which the EuroQol-5D and Arthritis self-efficacy scale were used to measure self-perceived health and self-efficacy and function was measured with Grip Ability Test for the upper extremity and five different functional tests for the lower extremity.</p> <p>Results</p> <p>We found differences between the intervention group and the control group, comparing the results at baseline and after 6 months in EuroQol-5D (p < 0.001) and in standing one leg eyes closed (p = 0.02) in favour of the intervention group. No other differences between the groups were found.</p> <p>Conclusion</p> <p>This study has shown that patient education for patients with osteoarthritis is feasible in a primary health care setting and can improve self-perceived health as well as function in some degree, but not self-efficacy. Further research to investigate the effect of exercise performance on function, as well as self-efficacy is warranted.</p> <p>Trial registration</p> <p>The trial is registered with ClinicalTrials.gov. Registration number: NCT00979914</p