Encoding of Compressive Stress During Indentation by Slowly Adapting Type I Mechanoreceptors in Rat Hairy Skin

2002 ◽  
Vol 87 (4) ◽  
pp. 1686-1693 ◽  
Author(s):  
Weiqing Ge ◽  
Partap S. Khalsa

The mechanical state encoded by slowly adapting type 1 mechanoreceptors (SAI) during indentation was examined using an isolated preparation in a rat model. Skin and its intact innervation were harvested from the medial thigh of the rat hindlimb and placed in a dish, with the corium side down, containing synthetic interstitial fluid. The margins of the skin were coupled to an apparatus that could stretch and apply compression to the skin. Using a standard teased nerve preparation, the neural responses of single SAIs were identified. SAIs were stimulated, using controlled compressive stress while simultaneously measuring displacement, by compressing the skin between indenters (flat cylinders) of different diameters and a hard platform. SAIs were subcategorized according to whether their neural response saturated above or below 10 kPa compressive stress (SAI-H or SAI-L, respectively). Linear regression was used to evaluate the relationships between neuron response and stress and force and displacement. For all SAIs, the mean neural response was significantly and substantially more highly correlated with compressive stress than force or displacement. For the SAI-L subcategory, the mean correlation coefficient was significantly and substantially greater for stress than for force but not significantly different for displacement. The data from this study support the hypothesis that SAI mechanoreceptors stimulated by indentation encode compressive stress rather than force, displacement, or strain.

2003 ◽  
Vol 89 (2) ◽  
pp. 785-792 ◽  
Author(s):  
Weiqing Ge ◽  
Partap S. Khalsa

The mechanical state encoded by group III and IV muscle afferents, putative mechano-nociceptors, during indentation was examined using an isolated muscle-nerve preparation in a rat model. Gracilis muscle and its intact innervation were surgically removed from the medial thigh of the rat hindlimb and placed in a dish containing rodent synthetic interstitial fluid. The tendons of the muscle were coupled to an apparatus that could stretch and apply compression to the muscle. Using a standard teased-nerve preparation, the neural responses of single mechanically sensitive group III or IV afferents were identified. Afferents were classified as mechano-nociceptors on the basis of their graded response to noxious levels of compressive stress (or strain) as well as, in some cases, their polymodal response to noxious thermal stimuli. Mechano-nociceptors ( n = 13) were stimulated using controlled compressive stress (10–30 kPa) or strain (40–80%) while simultaneously measuring displacement and force by compressing the muscle between a flat cylinder and a hard platform. Linear regression was used to evaluate the relationships between neural response and mechanical stress, force, strain, and displacement. The mean neural response (threshold: 1.1 ± 0.4 kPa; sensitivity: 0.5 ± 0.1 Hz/kPa; means ± SE) was significantly and substantially more highly correlated with compressive stress than force, strain, or displacement. The data from this study support the hypothesis that muscle nociceptors stimulated by indentation encode compressive stress rather than force, strain, or displacement.


2018 ◽  
Vol 4 (4) ◽  
pp. 519-522
Author(s):  
Jeyakumar S ◽  
Jagatheesan Alagesan ◽  
T.S. Muthukumar

Background: Frozen shoulder is disorder of the connective tissue that limits the normal Range of motion of the shoulder in diabetes, frozen shoulder is thought to be caused by changes to the collagen in the shoulder joint as a result of long term Hypoglycemia. Mobilization is a therapeutic movement of the joint. The goal is to restore normal joint motion and rhythm. The use of mobilization with movement for peripheral joints was developed by mulligan. This technique combines a sustained application of manual technique “gliding” force to the joint with concurrent physiologic motion of joint, either actively or passively. This study aims to find out the effects of mobilization with movement and end range mobilization in frozen shoulder in Type I diabetics. Materials and Methods: 30 subjects both male and female, suffering with shoulder pain and clinically diagnosed with frozen shoulder was recruited for the study and divided into two groups with 15 patients each based on convenient sampling method. Group A patients received mobilization with movement and Group B patients received end range mobilization for three weeks. The outcome measurements were SPADI, Functional hand to back scale, abduction range of motion using goniometer and VAS. Results: The mean values of all parameters showed significant differences in group A as compared to group B in terms of decreased pain, increased abduction range and other outcome measures. Conclusion: Based on the results it has been concluded that treating the type 1 diabetic patient with frozen shoulder, mobilization with movement exercise shows better results than end range mobilization in reducing pain and increase functional activities and mobility in frozen shoulder.


2010 ◽  
Vol 7 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Gregory J. Gerling

Background:The skin plays a role in conditioning mechanical indentation into distributions of stress/strain that mechanoreceptors convert into neural signals. Solid mechanics methods have modelled the skin to predict the in vivo neural response from mechanoreceptors. Despite their promise, current models cannot explain the role that anatomical positioning and receptor organ morphology play in producing differences in neural response. This work hypothesises that the skin's intermediate ridges may help explain, in part, the sensitivity of slowly adapting type I (SA-I) mechanoreceptors to edge stimuli.Method:Two finite-element models of the fingertip were built, validated and used to analyse the functionality of the intermediate ridges. One of the two-dimensional, cross-sectional models included intermediate ridges, while the other did not. The analysis sought to determine if intermediate ridges (1) increase the magnitude of strain energy density (SED) near the SA-I location and (2) help differentiate one 2.0-mm indenter from two 0.5-mm wide indenters with a 1.0-mm gap.Results:Higher concentrations of SED were found near the tips of the intermediate ridges, the anatomical location that coincides with the SA-I receptors. This first result suggested that the location of the SA-Is in the stiffer epidermal tissue helps magnify their response to edge stimuli. The second result was that both models were equally capable of predicting the spatial structure within the in vivo neural responses, and therefore the addition of intermediate ridges did not help in differentiating the indenters.Conclusion:The finding, a 15%–35% increase in response when the sampling point lies within the stiffer tissue at the same depth, seeks to inform the positioning of force sensors in robotic skin substrates.


Author(s):  
Meenal Batta ◽  
Rajeev Sharma ◽  
Naveenta Gupta ◽  
Sonia Garg ◽  
Gurmeet Kaur ◽  
...  

Background: Insulin-dependent (type 1) diabetes mellitus is associated with different degrees of neuropathies affecting peripheral as well as central neural pathways. The subclinical neurological involvement in diabetic children can be assessed by changes appearing in the electrophysiological parameters like Visual Evoked Potentials (VEPs). The objective of the study was to assess the effect of type I diabetes melitus on the visual evoked potentials in children.Methods: This cross-sectional case-control study was done on 30 children with type 1 diabetes mellitus of minimum two years duration as cases and 30 age and gender matched euglycemic children with normal HbA1c taken as controls. Visual Evoked Potentials (VEPs) were done on both the groups of children and the latencies (ms) of waves -N75, P100, N145 and amplitude (μV) of wave P100 were recorded. The data was compiled in the pre-designed proforma and statistically analysed using student t-test.Results: The increase in the mean latencies of waveforms of VEPs N75, P100 and amplitude P100 were found to be highly significant statistically (p<0.001) in both the eyes among the children with type 1 diabetes mellitus. The mean latency of waveform N145 was found to be statistically insignificant in the two groups (p>0.05).Conclusions: The type 1 diabetes does affect the visual pathways in children. Visual Evoked Potentials are helpful in the detection of early changes in the conduction across the neural pathways in the sub-clinical diseases.


2020 ◽  
Vol 20 (3) ◽  
pp. 1337-1343
Author(s):  
O Belhiba ◽  
Z Aadam ◽  
L Jeddane ◽  
R Saile ◽  
H Salih ALJ ◽  
...  

Introduction: Type I diabetes (T1D) is an autoimmune disease with a prediabetic, asymptomatic period characterized by the selective destruction of insulin-producing β cells. During the pre-clinical phase, various auto-antibodies are generated against several beta cell antigens such as anti glutamate acid decarboxylase (Anti-GAD), anti tyrosine phosphatase (Anti-IA2). Today, the coupled detection of Anti-IA2 with that of Anti-GAD proves its great importance in the diagnosis and prediction of type 1 diabetes. The combined positivity for both antibodies has a specificity and a positive predictive value of 100%. Objectives: In this work, we evaluate the diagnostic value of anti-GAD and anti-IA2 antibodies in a series based on 78 Moroccan subjects initially under 16, suspected T1D. Results and Discussion: Our series consists mainly of 74% of newly diagnosed patients for T1D and 26% of confirmed diagnostic patients, of whom 52% are females. The mean age of diagnosis is 7 ± 4 years, the mean of HbA1c at the time of diagnosis is 11.63 ± 2.16%, and the percentage of family history in our series is 69%. The proportion of positive results for anti-IA2 antibodies and anti-GAD antibodies are, respectively, 76.92% and 62.82%, and 52.56% of patients are positive for both auto-antibodies. This study confirms that anti-GAD and anti-IA2 auto-antibodies assays can detect patients early and the autoantibodies can persist several years after diagnosis of type 1 diabetes. Conclusion: This study confirmed the diagnosis and classification of T1D (type 1A) in 87.18% of patients, and we reported that the prevalence of anti-GAD and anti-IA2 is higher in girls than in boys. Keywords: Type 1 diabetes; autoimmunity; autoantibodies; anti-GAD; anti-IA2; ELISA; classification.


2019 ◽  
Vol 3 (3) ◽  

Background: Diabetes mellitus (DM) is a metabolic disease that can lead to many ocular complications such as increased Central Corneal Thickness (CCT), cataracts, and diabetic retinopathy. The aim of this study was to compare the CCT between subjects with type I and type II diabetes. Method: This was a retrospective study which included subjects with diabetes (with and without Diabetic Retinopathy (DR)) aged between 18 to 80 years old. The data collected were type and duration of diabetes mellitus, diabetes treatment, glycated hemoglobin level, visual acuity, CCT, and intra ocular pressure. Subjects were divided into subgroup (with and without DR). Statistical program (SPSS) was used to compare the central corneal thickness between the groups. Result: A total of 205 subjects with type I (n=100) and type II (n=105) diabetes were included in this study. In type 1 DM, the mean CCT was 547.06±27.3 microns in patients with diabetic retinopathy (DR) and 533.85±26.8 microns in patients without DR. In type 2 DM, the mean CCT was 542.85±39.3 microns in patients with DR and 532.44±27.4 microns in patients without DR. The CCT in type 1 diabetic patients was higher in both groups (with and without DR) than the CCT in type 2 diabetic patients in both groups (with and without DR). However, this was not statistically significant. Conclusion: The type of diabetes mellitus did not affect CCT. The presence of diabetic retinopathy in either type I or type II diabetes mellitus can affect the measurements of CCT.


2015 ◽  
Vol 27 (3) ◽  
pp. 396-403
Author(s):  
Shelby L. Francis ◽  
Ajay Singhvi ◽  
Eva Tsalikian ◽  
Michael J. Tansey ◽  
Kathleen F. Janz

Purpose:Determining fitness is important when assessing adolescents with type 1 diabetes mellitus (T1DM). Submaximal tests estimate fitness, but none have been validated in this population. This study cross-validates the Ebbeling and Nemeth equations to predict fitness (VO2max (ml/kg/min)) in adolescents with T1DM.Methods:Adolescents with T1DM (n = 20) completed a maximal treadmill test using indirect calorimetry. Participants completed one 4-min stage between 2.0 and 4.5 mph and 5% grade (Ebbeling/Nemeth protocol). Speed and grade were then increased until exhaustion. Predicted VO2max was calculated using the Ebbeling and Nemeth equations and compared with observed VO2max using paired t tests. Pearson correlation coefficients, 95% confidence intervals, coefficients of determination (R2), and total error (TE) were calculated.Results:The mean observed VO2max was 47.0 ml/kg/min (SD = 6.9); the Ebbeling and Nemeth mean predictions were 42.4 (SD = 9.4) and 43.5 ml/kg/min (SD = 6.9), respectively. Paired t tests resulted in statistically significant (p < .01) mean differences between observed and predicted VO2max for both predictions. The association between the Ebbeling prediction and observed VO2max was r = .90 (95% CI = 0.76, 0.96), R2 = .81, and TE = 6.5 ml/kg/min. The association between the Nemeth prediction and observed VO2max was r = .81 (95% CI = 0.57, 0.92), R2 = .66, and TE = 5.6 ml/kg/min.Conclusion:The Nemeth submaximal treadmill protocol provides a better estimate of fitness than the Ebbeling in adolescents with T1DM.


1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.


MEDISAINS ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 19
Author(s):  
Fairuz Fairuz ◽  
Hasna Dewi ◽  
Humaryanto Humaryanto

Background: Therapies for hyperglycemic treatment, including insulin and oral diabetes medications, have been confirmed to cause several side effects. Thus, finding new drugs with fewer side effects is of high importance. Salung leaf herb (Psychotria malayana Jack) reported used in traditional societies as a treatment for diabetes. However, the scientific proof of this plant for diabetes treatment is still lacking.Objective: To evaluate the antidiabetic effect of the P. malayana jack in induced type 1 diabetic rats by assessing blood glucose level and pancreatic cells in white rats.Methods: Alloxan used to induce type I diabetes. Rats randomly divided into six groups. A Group P1 received 250 mg/kg BW; group P2 received 500 mg/kg BW, group P3 received 1000 mg/kg BW. While group 4 basal received no treatment, group 5 received distilled water as a negative control, and group 6 received glibenclamide as a positive control. Medications are given for six days. Glucose levels were measured, and observation of pancreatic Langerhans cell damages.Results:  A decrease in blood glucose levels observed in all treatment groups. The most significant reduction (49.76%; 1000 mg/kg BW) occurred in the P3 group. Morphological features of pancreatic Langerhans cell damage were slightly high in the P1 group.Conclusion: P. malayana Jack can consider having an antidiabetic effect in a type 1 diabetic rat by reducing blood glucose levels.


2020 ◽  
Vol 26 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Jennifer M. Strahle ◽  
Rukayat Taiwo ◽  
Christine Averill ◽  
James Torner ◽  
Jordan I. Gewirtz ◽  
...  

OBJECTIVEIn patients with Chiari malformation type I (CM-I) and a syrinx who also have scoliosis, clinical and radiological predictors of curve regression after posterior fossa decompression are not well known. Prior reports indicate that age younger than 10 years and a curve magnitude < 35° are favorable predictors of curve regression following surgery. The aim of this study was to determine baseline radiological factors, including craniocervical junction alignment, that might predict curve stability or improvement after posterior fossa decompression.METHODSA large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and a syrinx (≥ 3 mm in width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°) in patients who underwent posterior fossa decompression and who also had follow-up imaging.RESULTSOf 825 patients with CM-I and a syrinx, 251 (30.4%) were noted to have scoliosis present at the time of diagnosis. Forty-one (16.3%) of these patients underwent posterior fossa decompression and had follow-up imaging to assess for scoliosis. Twenty-three patients (56%) were female, the mean age at time of CM-I decompression was 10.0 years, and the mean follow-up duration was 1.3 years. Nine patients (22%) had stable curves, 16 (39%) showed improvement (> 5°), and 16 (39%) displayed curve progression (> 5°) during the follow-up period. Younger age at the time of decompression was associated with improvement in curve magnitude; for those with curves of ≤ 35°, 17% of patients younger than 10 years of age had curve progression compared with 64% of those 10 years of age or older (p = 0.008). There was no difference by age for those with curves > 35°. Tonsil position, baseline syrinx dimensions, and change in syrinx size were not associated with the change in curve magnitude. There was no difference in progression after surgery in patients who were also treated with a brace compared to those who were not treated with a brace for scoliosis.CONCLUSIONSIn this cohort of patients with CM-I, a syrinx, and scoliosis, younger age at the time of decompression was associated with improvement in curve magnitude following surgery, especially in patients younger than 10 years of age with curves of ≤ 35°. Baseline tonsil position, syrinx dimensions, frontooccipital horn ratio, and craniocervical junction morphology were not associated with changes in curve magnitude after surgery.


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