scholarly journals Viscoelastic properties of the human colon

2001 ◽  
Vol 281 (2) ◽  
pp. G459-G466 ◽  
Author(s):  
Adil E. Bharucha ◽  
Rolf D. Hubmayr ◽  
Irene J. Ferber ◽  
Alan R. Zinsmeister
Keyword(s):  
Viscoelastic Properties ◽  
Healthy Subjects ◽  
Human Colon ◽  
Static Compliance ◽  
Balloon Distension ◽  
Before And After ◽  
Pressure Increment ◽  
Colonic Distension ◽  
Descending Colon ◽  
Intravenous Atropine

Our objectives were to characterize colonic viscoelastic properties of the human descending colon by assessing pressure-volume (P-V) relationships during barostatic balloon distension. In 16 healthy subjects, a balloon was inflated to 44 mmHg and then deflated to 0 mmHg in 4-mmHg steps at 10, 30, and 60 ml/min, allowing volume fluctuations to stabilize at each pressure increment. Thereafter, these “quasi-static” P-V curves were compared with “dynamic” distensions to 300 ml, at 1 and 10 ml/s, before and after intravenous atropine in another five subjects. During quasi-static curves, balloon volume stabilized at each pressure increment. Quasi-static P-V curves were reproducible within individuals and approximated to a power exponential function and revealed hysteresis, indicative of viscoelasticity. Body mass index influenced quasi-static P-V curves during inflation but not during deflation. The colon was less compliant during dynamic distensions at 10 ml/s than during quasi-static distensions. Atropine increased quasi-static compliance and attenuated differences between quasi-static and rapid distensions. We conclude that colonic viscoelastic properties can be assessed by quasi-static P-V curves. Rapid colonic distension activated neural reflexes, thereby reducing colonic compliance compared with quasi-static distensions.

Some Aspects of Pulmonary Function after Rapid Saline Infusion in Healthy Subjects

1973 ◽  
Vol 45 (3) ◽  
pp. 407-410 ◽  
Author(s):  
J. V. Collins ◽  
G. M. Cochrane ◽  
Jane Davis ◽  
S. R. Benatar ◽  
T. J. H. Clark
Keyword(s):  
Healthy Subjects ◽  
Dynamic Compliance ◽  
Upright Position ◽  
Closing Volume ◽  
Healthy Male ◽  
Static Compliance ◽  
Lung Volumes ◽  
Marked Individual ◽  
Before And After ◽  
Made In

1. Rapid intravenous (i.v.) infusions of saline were administered to five healthy male volunteers. Measurements were made of static and dynamic lung volumes, ‘closing volume’ and pulmonary compliance before and after infusion; all measurements were made in the seated upright position. 2. Following a 1 litre infusion small decreases occurred in static and dynamic lung volumes in all studies and were associated in each case with an increase in ‘closing volume’. ‘Closing volume’ returned to normal within 1 h of the infusion. 3. After 2 litre infusions more marked decreases in all lung volumes occurred and were associated with variable changes in ‘closing volume’. The pattern of change varied between individual subjects and this is thought to reflect differences in localization within the lungs of the effects of the saline load in different subjects. 4. After 2 litre infusions static compliance was decreased in all subjects during the first 10–15 min. Changes in dynamic compliance showed marked individual variation.

The influence of osteopathic correction on the viscoelastic characteristics of the lower leg muscles

2019 ◽  
pp. 93-98
Author(s):  
E. M. Timanin ◽  
N. S. Sydneva ◽  
A. A. Zakharova
Keyword(s):  
Viscoelastic Properties ◽  
Gastrocnemius Muscle ◽  
Soft Tissues ◽  
Subjective Assessment ◽  
Lymphatic Drainage ◽  
Intercellular Substance ◽  
Leg Muscles ◽  
Before And After ◽  
Viscoelastic Characteristics ◽  
Instrumental Methods

Introduction. To date there is a lack of studies dedicated to the objectification of the palpation data obtained by a specialist during the osteopathic examination. The issue of the evidence of the results of osteopathic correction still remains important. Search for instrumental methods allowing to register and to measure various palpation phenomena and manifestations of somatic dysfunctions is very relevant for the development of osteopathy as a science. It is also very important to find objective characteristics of these methods.Goal of research — to study viscoelastic characteristics of the soft tissues of the lower legs by palpation and instrumental methods before and after osteopathic correction.Materials and methods. 22 volunteers (12 women and 10 men) aged 18–23 years without complaints of the musculoskeletal system were examined. Osteopathic diagnostics and measurement of the viscoelastic properties of muscles were carried out by the method of vibration viscoelastometry before and after osteopathic correction.Results. Correlation analysis by Spearman showed that the subjective assessment of an osteopath positively correlated with both elasticity (r=0,43, p<0,05) and viscosity of soft issues (r=0,29, p<0,05). For the gastrocnemius muscle, this pattern was even more pronounced — for elasticity r=0,51, p<0,05, for viscosity =0,34, p<0,05. After osteopathic correction no changes in the elasticity of the soft tissues were observed. The viscosity of the tissues reduced, but in the projection of the gastrocnemius muscle, these changes were not statistically significant (p=0,12), whereas in the projection of the soleus muscle statistically significant changes (p=0,034) were observed.Conclusion. Changes in the viscoelastic properties of tissues demonstrated that the effects of osteopathic correction with the use of myofascial mobilization techniques, articulation mobilization techniques, and lymphatic drainage techniques were not obvious. The elasticity of soft tissues of the lower legs did not change, while the viscosity decreased, especially in the projection of the soleus muscles. This effect of the osteopathic correction can be associated with the effect of thixotropy — the transformation of gel-like intercellular substance into sol. Thus, the research showed that vibration viscoelastometry can be used for the objectifi cation of the condition of soft tissues and of the effects of osteopathic correction.

scholarly journals A Novel Language Paradigm for Intraoperative Language Mapping: Feasibility and Evaluation

2021 ◽  
Vol 10 (4) ◽  
pp. 655
Author(s):  
Katharina Rosengarth ◽  
Delin Pai ◽  
Frank Dodoo-Schittko ◽  
Katharina Hense ◽  
Teele Tamm ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Intraoperative Complications ◽  
Evaluation Study ◽  
Awake Craniotomy ◽  
Language Mapping ◽  
Tumor Patients ◽  
Language Functions ◽  
Before And After ◽  
Assessment Time ◽  
Neuropsychological Outcomes

(1) Background—Mapping language using direct cortical stimulation (DCS) during an awake craniotomy is difficult without using more than one language paradigm that particularly follows the demand of DCS by not exceeding the assessment time of 4 s to prevent intraoperative complications. We designed an intraoperative language paradigm by combining classical picture naming and verb generation, which safely engaged highly relevant language functions. (2) Methods—An evaluation study investigated whether a single trial of the language task could be performed in less than 4 s in 30 healthy subjects and whether the suggested language paradigm sufficiently pictured the cortical language network using functional magnetic resonance imaging (fMRI) in 12 healthy subjects. In a feasibility study, 24 brain tumor patients conducted the language task during an awake craniotomy. The patients’ neuropsychological outcomes were monitored before and after surgery. (3) Results—The fMRI results in healthy subjects showed activations in a language-associated network around the (left) sylvian fissure. Single language trials could be performed within 4 s. Intraoperatively, all tumor patients showed DCS-induced language errors while conducting the novel language task. Postoperatively, mild neuropsychological impairments appeared compared to the presurgical assessment. (4) Conclusions—These data support the use of a novel language paradigm that safely monitors highly relevant language functions intraoperatively, which can consequently minimize negative postoperative neuropsychological outcomes.

Changes In Prothrombin And Activated Partial Thromboplastin Time During Replacement Therapy With Human Recombinant Growth Hormone In Growth Hormone Deficient Adults

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S102-S103
Author(s):  
Y S Kamel
Keyword(s):  
Growth Hormone ◽  
Replacement Therapy ◽  
Healthy Subjects ◽  
Recombinant Growth Hormone ◽  
Gh Replacement ◽  
Coagulation Tests ◽  
Before And After ◽  
Human Recombinant Growth Hormone ◽  
Male Patients ◽  
One Year

Abstract Introduction/Objective The aim of this study was to investigate the effects of GH administration on basic coagulation parameters: PT, aPTT and fibrinogen concentrations in adult GHD patients before and during one year of GH replacement. Methods Twenty-one adult patients with severe GHD (mean age +/- SE: 38.6 +/- 2.8 years) were included in this hospital based, prospective, interventional study. All patients were treated with rhGH for 12 months (GH dose: 0.4 mg/day for male and 0.6 mg/day for female patients). IGF-1 concentrations were determined using RIA-INEP kits. Basic coagulation tests, i.e. aPTT and fibrinogen concentrations, were measured before and after 3, 6 and 12 months of treatment with rhGH. Control values were obtained from fourteen “healthy” subjects matched by age, sex and body mass index (BMI). Results At baseline, we observed no significant differences in PT, aPTT and fibrinogen values between GHD and healthy subjects. IGF-1 concentrations increased significantly within 3 months of GH therapy (8.2 +/- 1.5 vs. 24.2 +/- 2.9 nmol/l, p &lt;0.05) and remained stable thereafter. A significant increase in PT values, which was more pronounced in female subjects, was noted after 6 and 12 months of treatment with GH. aPTT values increased significantly after 12 months of treatment only in male patients (28.8 +/- 4.6 vs. 39.7 +/- 2.1 s.; p &lt;0.05). No significant changes in fibrinogen concentrations were found during the study. Conclusion Twelve months of GH replacement therapy led to a significant increase in PT and aPTT values in adult GHD patients, while fibrinogen concentrations did not change. Changes in PT were more pronounced in female GHD patients, while an increase in aPTT values was observed only in male patients with GHD. The clinical significance of these changes needs further evaluation.

Effects of activation frequency and force on low-frequency fatigue in human skeletal muscle

1999 ◽  
Vol 86 (4) ◽  
pp. 1337-1346 ◽  
Author(s):  
Stuart A. Binder-Macleod ◽  
David W. Russ
Keyword(s):  
Healthy Subjects ◽  
Human Skeletal Muscle ◽  
Low Frequency ◽  
Variable Frequency ◽  
Activation Pattern ◽  
Constant Frequency ◽  
Mean Frequency ◽  
Before And After ◽  
Low Frequency Fatigue ◽  
Force Time

No comparison of the amount of low-frequency fatigue (LFF) produced by different activation frequencies exists, although frequencies ranging from 10 to 100 Hz have been used to induce LFF. The quadriceps femoris of 11 healthy subjects were tested in 5 separate sessions. In each session, the force-generating ability of the muscle was tested before and after fatigue and at 2, ∼13, and ∼38 min of recovery. Brief (6-pulse), constant-frequency trains of 9.1, 14.3, 33.3, and 100 Hz and a 6-pulse, variable-frequency train with a mean frequency of 14.3 Hz were delivered at 1 train/s to induce fatigue. Immediately postfatigue, there was a significant effect of fatiguing protocol frequency. Muscles exhibited greater LFF after stimulation with the 9.1-, 14.3-, and variable-frequency trains. These three trains also produced the greatest mean force-time integrals during the fatigue test. At 2, ∼13, and ∼38 min of recovery, however, the LFF produced was independent of the fatiguing protocol frequency. The findings are consistent with theories suggesting two independent mechanisms behind LFF and may help identify the optimal activation pattern when functional electrical stimulation is used.

Lymphocyte subsets are influenced by positivity levels in healthy subjects before and after mild acute stress

2017 ◽  
Vol 188 ◽  
pp. 13-20 ◽  
Author(s):  
Gian Vittorio Caprara ◽  
Roberto Nisini ◽  
Valeria Castellani ◽  
Pasquali Vittorio ◽  
Guido Alessandri ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Lymphocyte Subsets ◽  
Acute Stress ◽  
Before And After

Dysprosium-enhanced MR imaging for tumor tissue characterization

1997 ◽  
Vol 38 (2) ◽  
pp. 281-286 ◽  
Author(s):  
C. Wang ◽  
A. Sundin ◽  
A. Ericsson ◽  
T. Bach-Gansmo ◽  
A. Hemmingsson ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Tissue Characterization ◽  
Tumor Tissue ◽  
Tumor Model ◽  
Human Colon ◽  
Mr Images ◽  
Histological Sections ◽  
Necrotic Tumor ◽  
Before And After ◽  
Weighted Sequences

Purpose: to evaluate dysprosium-enhanced MR imaging for differentiation between morphologically intact and necrotic tumor tissue in a tumor model. Material and Methods: A human colon carcinoma was transplanted subcutaneously into 9 nude (immunodeprived) rats. MR imaging was performed before and after injection of the dysprosium agent Dy-DTPA-BMA. T1-, T2- and T2*-weighted sequences were acquired. the tumors were dissected, histological sections were prepared, and compared with corresponding MR images. Results: in intact tissue, the MR signal intensity in the T2- and T2*-weighted images decreased after Dy injection and the delineation of the intact regions were sharp and corresponded well to the gross histological sections. Conclusion: Dy-enhanced MR imaging facilitated the differentiation between intact and necrotic tumor tissue.

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