A review: neural control of mastication in humans as influenced by food texture

This review summerizes recent approaches to the physiology of the masticatory system in humans that aim to understand how the process is influenced by the material properties of foods. The centerpiece is a group of experiments that show that the rate of breakdown of food in human mastification depends principally on the combination of two mechanical properties of foods: toughness(R) and modulus of elasticity (E). Two mechanical indices are constructed from these properties: the square root of their product, (ER)0.5, is predicted to explain the resistance to an incisal bite, while the square root of their ratio, (R/E)0.5 is predicted to control the rate of fragmentation during a postcanie bite. Evidence for the latter is reviewed, which also appears to modulate the activity of jaw closing muscles and the extent of lateral mandibular movement during mastication. These studies provide a quantified link between This review summerizes recent approaches to the physiology of the masticatory system in humans that aim to understand how the process is influenced by the material propoerties of foods, the centerpiece is a group of experiments that show that the rate of breakdown of food in human mastification depends principally on the combination of two mechanical properties of. foods: toughness(R) and modulus of elasticity (E).'-Two mechanical indices are constructed from these properties: the square root of their product,. (ER)°5, is predicted to explain the rsistance to an incisal bite, while the square root of their ratio, (R/E)0-5 is predicted to control the rate of fragmentation during a postcanie bite. Evidence for the latter is reviewed, which also appears to modulate the activity of jaw closing muscles and the extent of lateral mandibular movement during mastication. These studies provide a quantified link between the food stimulus and the physiological response of the mastiatory system for which we know of no parellel. Attempts to extend this analysis have been made by psychophysical investigations of food texture. These support some sensitivity to the mechanical index that we have identified; but are not conclusive.' Finally,' we provide a chart summarizing physiological responses to food texture that could interest dentists, food scientists and also those interested in the analysis of dentition and diet in mammals. the food stimulus and the physiological response of the mastiatory system for which we know of no parallel. Attempts to extend this analysis have been made by psychophysical investigations of food texture. These support some sensitivity to the mechanical index that we have identified, but are not conclusive. Finally, we provide a chart summarizing physiological responses to food texture that could interest dentists, food scientists and also those interested in the analysis of dentition and diet in mammals.published_or_final_versio

Food properties that influence neuromuscular activity during human mastication

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Relationship between blood lead concentration and nutritional status among Malay primary school children in Kuala Lumpur, Malaysia.

A cross-sectional study was conducted to identify the relationship between blood lead concentration and nutritional status among primary school children in Kuala Lumpur. A total of 225 Malay students, 113 male and 112 female, aged 6.3 to 9.8 were selected through a stratified random sampling method. The random blood samples were collected and blood lead concentration was measured by a Graphite Furnace Atomic Absorption Spectrophotometer. The nutrient intake was determined by the 24-hour Dietary Recall method and Food Frequency Questionnaire. An anthropometric assessment was reported according to growth indices (z-scores of weight-for-age, height-for-age, and weight-for-height). The mean blood lead concentration was low (3.4 ± 1.91 ug/dL) and was significantly different between gender. Only 14.7% of the respondents fulfilled the daily energy requirement. The protein and iron intakes were adequate for a majority of the children. However, 34.7% of the total children showed inadequate intake of calcium. The energy, protein, fat and carbohydrate intakes were significantly different by gender, that is, males had better intake than females. Majority of respondents had normal mean z-score of growth indices. Ten percent of the respondents were underweight, 2.8% wasted and 5.4% stunted. Multiple linear regression showed inverse significant relationships between blood lead concentration with children's age (β= -0.647, p<0.001) and per capita income (β=-0.001, p=0.018). There were inverse significant relationships between blood lead concentration with children's age (β=-0.877, p=0.001) and calcium intake (β= -0.011,p=0.014) and positive significant relationship with weight-for-height (β=0.326, p=0.041) among those with inadequate calcium intake. Among children with inadequate energy intake, children's age (β= -0.621, p< 0.001), per capita income (β= -0.001,p=0.025) and protein intake (β= -0.019, p=0.027) were inversely and significantly related with blood lead concentration. In conclusion, nutritional status might affect the children's absorption of lead and further investigation is required for confirmation

Very Cold Gas and Dark Matter

We have recently proposed a new candidate for baryonic dark matter: very cold molecular gas, in near-isothermal equilibrium with the cosmic background radiation at 2.73 K. The cold gas, of quasi-primordial abundances, is condensed in a fractal structure, resembling the hierarchical structure of the detected interstellar medium. We present some perspectives of detecting this very cold gas, either directly or indirectly. The H$_2$ molecule has an "ultrafine" structure, due to the interaction between the rotation-induced magnetic moment and the nuclear spins. But the lines fall in the km domain, and are very weak. The best opportunity might be the UV absorption of H$_2$ in front of quasars. The unexpected cold dust component, revealed by the COBE/FIRAS submillimetric results, could also be due to this very cold H$_2$ gas, through collision-induced radiation, or solid H$_2$ grains or snowflakes. The $\gamma$-ray distribution, much more radially extended than the supernovae at the origin of cosmic rays acceleration, also points towards and extended gas distribution.Comment: 16 pages, Latex pages, crckapb macro, 3 postscript figures, uuencoded compressed tar file. To be published in the proceeedings of the "Dust-Morphology" conference, Johannesburg, 22-26 January, 1996, D. Block (ed.), (Kluwer Dordrecht

Redox proteomics of the inflammatory secretome identifies a common set of redoxins and other glutathionylated proteins released in inflammation, influenza virus infection and oxidative stress

Protein cysteines can form transient disulfides with glutathione (GSH), resulting in the production of glutathionylated proteins, and this process is regarded as a mechanism by which the redox state of the cell can regulate protein function. Most studies on redox regulation of immunity have focused on intracellular proteins. In this study we have used redox proteomics to identify those proteins released in glutathionylated form by macrophages stimulated with lipopolysaccharide (LPS) after pre-loading the cells with biotinylated GSH. Of the several proteins identified in the redox secretome, we have selected a number for validation. Proteomic analysis indicated that LPS stimulated the release of peroxiredoxin (PRDX) 1, PRDX2, vimentin (VIM), profilin1 (PFN1) and thioredoxin 1 (TXN1). For PRDX1 and TXN1, we were able to confirm that the released protein is glutathionylated. PRDX1, PRDX2 and TXN1 were also released by the human pulmonary epithelial cell line, A549, infected with influenza virus. The release of the proteins identified was inhibited by the anti-inflammatory glucocorticoid, dexamethasone (DEX), which also inhibited tumor necrosis factor (TNF)-α release, and by thiol antioxidants (N-butanoyl GSH derivative, GSH-C4, and N-acetylcysteine (NAC), which did not affect TNF-α production. The proteins identified could be useful as biomarkers of oxidative stress associated with inflammation, and further studies will be required to investigate if the extracellular forms of these proteins has immunoregulatory functions

Tissue Microenvironments Define and Get Reinforced by Macrophage Phenotypes in Homeostasis or during Inflammation, Repair and Fibrosis

Current macrophage phenotype classifications are based on distinct in vitro culture conditions that do not adequately mirror complex tissue environments. In vivo monocyte progenitors populate all tissues for immune surveillance which supports the maintenance of homeostasis as well as regaining homeostasis after injury. Here we propose to classify macrophage phenotypes according to prototypical tissue environments, e.g. as they occur during homeostasis as well as during the different phases of (dermal) wound healing. In tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce proinflammatory macrophages by Toll-like receptors or inflammasomes. Such classically activated macrophages contribute to further tissue inflammation and damage. Apoptotic cells and antiinflammatory cytokines dominate in postinflammatory tissues which induce macrophages to produce more antiinflammatory mediators. Similarly, tumor-associated macrophages also confer immunosuppression in tumor stroma. Insufficient parenchymal healing despite abundant growth factors pushes macrophages to gain a profibrotic phenotype and promote fibrocyte recruitment which both enforce tissue scarring. Ischemic scars are largely devoid of cytokines and growth factors so that fibrolytic macrophages that predominantly secrete proteases digest the excess extracellular matrix. Together, macrophages stabilize their surrounding tissue microenvironments by adapting different phenotypes as feed-forward mechanisms to maintain tissue homeostasis or regain it following injury. Furthermore, macrophage heterogeneity in healthy or injured tissues mirrors spatial and temporal differences in microenvironments during the various stages of tissue injury and repair. Copyright (C) 2012 S. Karger AG, Base

Contributions of myofascial pain in diagnosis and treatment of shoulder pain. A randomized control trial

<p>Abstract</p> <p>Background</p> <p>Rotator cuff tendinopathy and subacromial impingement syndrome present complex patomechanical situations, frequent difficulties in clinical diagnosis and lack of effectiveness in treatment. Based on clinical experience, we have therefore considered the existence of another pathological entity as the possible origin of pain and dysfunction. The hypothesis of this study is to relate subacromial impingement syndrome (SIS) with myofascial pain syndrome (MPS), since myofascial trigger points (MTrPs) cause pain, functional limitation, lack of coordination and alterations in quality of movement, even prior to a tendinopathy. MTrPs can coexist with any degenerative subacromial condition. If they are not taken into consideration, they could perpetuate and aggravate the problem, hindering diagnosis and making the applied treatments ineffective.</p> <p>The aims and methods of this study are related with providing evidence of the relationship that may exist between this condition and MPS in the diagnosis and treatment of rotator cuff tendonitis and/or SIS.</p> <p>Method/design</p> <p>A descriptive transversal study will be made to find the correlation between the diagnosis of SIS and rotator cuff tendonitis, positive provocation test responses, the existence of active MTrPs and the results obtained with ultrasonography (US) and Magnetic Renonance Imaging (MRI). A randomized double blinded clinical trial will be carried out in experimental conditions: A Protocolized treatment based on active and passive joint repositioning, stabilization exercises, stretching of the periarticular shoulder muscles and postural reeducation. B. The previously described protocolized treatment, with the addition of dry needling applied to active MTrPs with the purpose of isolating the efficacy of dry needling in treatment.</p> <p>Discussion</p> <p>This study aims to provide a new vision of shoulder pain, from the perspective of MPS. This syndrome can, by itself, account for shoulder pain and dysfunction, although it can coexist with real conditions involving the tendons.</p> <p>Trail Registration</p> <p>ISRCTN Number: 30907460</p

Clonal analysis of palmar fibromatosis: a study whether palmar fibromatosis is a real tumor

BACKGROUND: Palmar fibromatosis that arises in the palmar soft tissue is characterized by infiltrative growth with a tendency toward local recurrence but does not metastasize. This study investigated the clonality of this process in twelve female patients, each with a single lesion, by examining the pattern of X-chromosome inactivation. METHODS: Hematoxylin and eosin stained sections of formalin-fixed, paraffin-embedded tissues were microdissected by laser capture microdissection to obtain the proliferative spindle cells. Tumor cells were isolated from the sections of rectum adenocarcinoma, and used for positive control. The genomic DNAs was extracted with phenol-chloroform, digested with a methylation-sensitive restriction endonuclease HpaII, and amplified by polymerase chain reaction (PCR), using primers targeted to a highly polymorphic short tandem repeat (STR) of the human androgen receptor gene (HUMARA). RESULTS: Among the twelve samples, three samples failed amplification, one sample showed homozygosity which was not suitable for further analysis, eight samples were successfully amplified, and showed a random X chromosome inactivation pattern, suggesting polyclonality of these lesions. CONCLUSION: The current findings suggest that palmar fibromatosis is a reactive proliferation rather than a clonal neoplasm