Responses of the Heliozoon Actinophrys Sol to Prey, to Mechanical Stimulation, and to Solutions of Proteins and Certain Other Substances

1960 ◽  
Vol 37 (2) ◽  
pp. 407-416
Author(s):  
J. A. KITCHING
Keyword(s):  
Body Surface ◽  
Tap Water ◽  
The Body ◽  
Albumin Solution ◽  
Egg Albumin ◽  
Other Substances ◽  
Γ Globulins ◽  
Skin Formation ◽  
Actinophrys Sol

1. Various flagellates and small ciliates stick to the axopods of Actinophrys. Contact with the base of an axopod or with the body surface leads to the outgrowth of a food funnel, by which the prey is ultimately surrounded. 2. If a fine probe or micropipette touches the body surface or the base of an axopod, a small cup may grow out over it, investing it closely, but the instrument is soon released. A squirt of tap water from a micropipette may also provoke the outgrowth of a small lobe or cup, or local pinocytosis. 3. Contact with, or a squirt from, a micropipette containing a solution of egg albumin provokes a more extensive reaction. The micropipette usually becomes invested extensively. The micropipette is drawn into the body and held there for up to an hour. 4 Immersion in egg albumin solution leads to a temporary spreading and lobulation of the axopod bases, and later a ‘skin’ may separate from the body surface. Skin formation is more pronounced in serum albumin solution, and may also be induced by γ-globulins and gelatin. 5. On treatment in vivo with toluidine blue or thionine a violet layer in the body surface separates as a pinkish violet or violet skin, leaving the body surface unstained. 6. There is evidence that the skin-forming substance is associated directly or indirectly with the maintenance of cell shape.

scholarly journals Cutaneous Hypersensitivity as an Indicator of Visceral Inflammation via C-Nociceptor Axon Bifurcation

2020 ◽  
Author(s):  
Yehong Fang ◽  
Shu Han ◽  
Xiaoxue Li ◽  
Yikuan Xie ◽  
Bing Zhu ◽  
...  
Keyword(s):  
Body Surface ◽  
The Body ◽  
Visceral Organ ◽  
Deep Tissue ◽  
Nociceptive Neurons ◽  
Chemically Induced ◽  
Acute Gastritis ◽  
Cutaneous Hypersensitivity ◽  
Evans Blue Extravasation

Abstract Pain on the body surface can accompany disorders in the deep tissue or internal organs. However, the anatomical and physiological mechanisms are obscure. Here, we provided direct evidence of axon bifurcation in primary C-nociceptive neurons that innervate both the skin and a visceral organ. Double-labeled dorsal root ganglion (DRG) neurons and Evans blue extravasation were observed in 3 types of chemically-induced visceral inflammation (colitis, urocystitis, and acute gastritis) rat models. In the colitis model, mechanical hypersensitivity and spontaneous activity were recorded in vivo from double-labeled C-nociceptive neurons in S1 or L6 DRGs. These neurons showed significantly enhanced responses to both somatic stimulation and colorectal distension. Our findings suggest that the branching of C-nociceptor axons contribute to cutaneous hypersensitivity in visceral inflammation. Cutaneous hypersensitivity on certain locations of the body surface might serve as an indicator of pathological conditions in the corresponding visceral organ.

scholarly journals The Physiology Of Contractile Vacuoles

1938 ◽  
Vol 15 (1) ◽  
pp. 143-151
Author(s):  
J. A. KITCHING
Keyword(s):  
Body Surface ◽  
Sucrose Solution ◽  
Tap Water ◽  
The Body ◽  
Partial Recovery ◽  
A Value ◽  
Contractile Vacuoles ◽  
Cyanide Solutions ◽  
Initial Check ◽  
Normal Difference

1. The rate of output of fluid from the contractile vacuoles of fresh-water peritrich ciliates was reduced in solutions of sulphide of concentration not less than M/1000. This effect was reversible. 2. Cyanide depressed the rate of vacuolar output in a concentration of M/100,000, but was more effective in higher concentrations (M/1000). In cyanide solutions there was (a) either a severe initial check or a temporary stoppage of the vacuole, and then later (b) a partial recovery of the rate of output to a value which was still much below the normal. During the initial check the body swelled. 3. Return of the organism from cyanide solution to tap water was followed by a sharp increase in the rate of vacuolar output to an abnormally high value. The body then shrank gradually to its normal size, and the rate of output also fell slowly to normal. 4. The swelling of the body which followed treatment of the organism with cyanide could be exactly counteracted by the addition of sucrose to the outside medium in a 0.05 M concentration. 5. It is concluded that the normal difference of osmotic pressure across the body surface is equivalent to that of a 0.05 M sucrose solution, and that this difference is maintained by the contractile vacuole. 6. The permeability of the body surface to water is estimated as 0.125-0.25 cubic micra per square micron per atmosphere per minute.

An Apparatus for Measuring the Effective Thermal Conductivity of the Body Surface

1999 ◽  
Author(s):  
Shuxia Cheng ◽  
Hongbo Zhang ◽  
Dawei Luo ◽  
Dayong Gao
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Body Surface ◽  
Silicone Rubber ◽  
The Body ◽  
Platinum Wire ◽  
Time Interval ◽  
The Wire ◽  
Predetermined Time

Abstract To prevent body from injury during the hyper- and hypo-thermic therapy, knowledge of the temperature distribution in the body surface (e.g. skin or tissue) close to the therapy location is needed. In order to predict, by calculation, the correct temperature field, it is essential to input meaningful values of the thermal properties of the body surface into numerical and analytical simulation models of its behavior during heating or cooling. A simple experimental apparatus for measuring effective thermal conductivity of the body surface has been developed. It differs from the previously developed apparatus. In experiments, a fine platinum wire (0.01 mm in diameter) with electrical resistance R (0.4Ω)is embedded between a tested specimen (body surface) and a silicone rubber. When the wire, specimen and rubber are in thermal equilibrium, and a constant electrical power is applied to the wire, the temperature increase of the wire against logarithm time in predetermined time interval was measured. The kinetics of this temperature rising is related to the thermal conductivity of the tested specimen and silicone rubber. The thermal conductivity of the silicone rubber is known from reference or measured. So the thermal conductivity of tested specimen can be calculated by measuring the temperature rise of platinum wire at predetermined time interval. It is assumed that (1) the wire is infinite long and the heat source is steady, (2) the tested medium (e.g. the tested specimen and the silicone rubber) are infinite large in space, and contact resistance between the fine wire and soft medium is negligible. The apparatus’ validity has been demonstrated by the following tests. First, as the standard specimen, thermal conductivity of glycerol and fused quartz glass (99.9% SiO2) were respectively measured using the apparatus. The relative errors between measured thermal conductivity and data provided by Thermophysical Properties Research Center (TPRC) are less than 0.7%. The validity of the theory model was also confirmed using several inorganic specimens and biological materials (e.g. rabbit sin, in vivo). Conditions and prerequisites for application of the technique and apparatus to measuring thermal conductivity of biomaterials (in vivo) were discussed.

Dimensions of Central Venous Structures in Humans Measured in vivo using Magnetic Resonance Imaging: Implications for Central-Vein Catheter Dimensions

2002 ◽  
Vol 25 (2) ◽  
pp. 107-123 ◽  
Author(s):  
Z.J. Twardowski ◽  
R.M. Seger
Keyword(s):  
Surface Area ◽  
Body Surface Area ◽  
Body Surface ◽  
The Body ◽  
Upper Body ◽  
Central Vein ◽  
Resonance Imaging ◽  
Vein Catheter ◽  
Central Vein Catheter

The tip of a central vein catheter for hemodialysis should be located in the upper right atrium for the best performance. Hemodialysis catheters do have internal diameters unadjusted to the catheter length; however, the longer the catheter the slower the flow at the same pressure difference. On the other hand, the catheter diameter cannot be so large as to fill the vein too tightly as it predisposes to damage of the vein wall, thrombosis and stenosis. Therefore, the catheter length and diameter should be appropriate for the patient. For this purpose, the exact dimensions of the venous system in vivo should be known. In this study we correlated the anthropometric measurements and the dimensions of the large upper body veins in 31 adult volunteers. After deep inspiration, magnetic resonance imaging of the chest was performed in three planes; the positions of specific points in the three-dimensional coordinate system were measured, and the distance to adjacent points was calculated according to the analytic geometry formula. The total length from the catheter entry point to the right atrium was the sum of distances between the adjacent points. The lengths of the veins were correlated with the body anthropometric measurements (height, weight, body surface area, bi-acromion span, and height plus bi-acromion span). The best overall correlations of the lengths and diameters of the large upper body veins are with the body surface area. A table is included to guide the selection of the total catheter length and diameter in relation to the body surface area and insertion site.

scholarly journals Ventriculoiliac shunt: a cadaveric feasibility study

2015 ◽  
Vol 15 (3) ◽  
pp. 310-312 ◽  
Author(s):  
R. Shane Tubbs ◽  
Isaiah Tubbs ◽  
Marios Loukas ◽  
Aaron A. Cohen-Gadol
Keyword(s):  
Vascular System ◽  
Tap Water ◽  
The Body ◽  
Time Of Death ◽  
Infusion Site ◽  
Fluid Accumulation ◽  
Marrow Space ◽  
Human Cadavers ◽  
Thoracic And Abdominal

OBJECT Additional distal sites for placement of CSF diversionary shunts may be necessary in some patients. The present study aimed to investigate the marrow space of the ilium as a potential receptacle for CSF in patients with hydrocephalus. METHODS Cannulation of the marrow space of the ilium was performed in 5 fresh human cadavers less than 4 hours from time of death. Tap water was infused via a metal trocar for approximately 60 minutes. RESULTS A total of 30 L of water was easily injected into all cadaveric specimens without overflow from the infusion site or noticeable edema of the body. Upon inspection of the thoracic and abdominal cavities, no fluid accumulation was identified, ensuring that all infused fluid had gone into the vascular system. CONCLUSIONS Based on this cadaveric study, the ilium appears to be an ideal location for placement of the distal end of a CSF diversionary shunt when other anatomical receptacles are not an option. In vivo human studies are now required to verify these findings.

scholarly journals The use of chitosan-based biomaterials for the treatment of hard-healing wounds

2019 ◽  
Vol 73 ◽  
pp. 768-781
Author(s):  
Marta Kędzierska ◽  
Katarzyna Miłowska
Keyword(s):  
Wound Healing ◽  
Chronic Wounds ◽  
Healing Process ◽  
Medical Engineering ◽  
Fibrin Clot ◽  
The Body ◽  
Complex Process ◽  
Other Substances

Wound healing is a complex process that engages skin cells, the blood, the immune system and a number of circulating substances in the body. Infections, contamination of the wound or a vast area of damage complicate and delay the natural process of skin regeneration. The incidence of hard-to-heal wounds is an increasingly common problem, because they can significantly impair the quality of life of the patient. For this reason, it is extremely important to look for factors (drugs, dressings or other substances) that could accelerate and relieve wound healing. Among many compounds in the area of medical engineering interest, attention should be paid to natural polysaccharides, e.g. chitosan and alginate. This article is devoted to biomaterials that play an important role in the treatment of chronic wounds. These include the following: hydrogels, non-wovens, membranes and chitosan sponges as well as chitosan-alginate composites or chitosan composites combined with zinc oxide and nanosilver. The material, which has chitosan as a base, works on all stages of the healing process. Many in vitro, in vivo and clinical studies that provide the basis for using chitosan materials as a substitute for conventional bandages and dressings have been carried out. At the stage of hemostasis, it accelerates platelet aggregation and the formation of a fibrin clot. In the inflamed stage, they cause the proliferation of neutrophils and macrophages that cleanse the wound, releasing cytokines at the wound site. Studies have shown that chitosan mimics the native extracellular matrix, providing the optimal microenvironment for the wound.

scholarly journals Real-Time Closed-Loop Suppression of Repolarization Alternans Reduces Arrhythmia Susceptibility In Vivo

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Faisal M. Merchant ◽  
Omid Sayadi ◽  
Kwanghyun Sohn ◽  
Eric H. Weiss ◽  
Dheeraj Puppala ◽  
...  
Keyword(s):  
Real Time ◽  
Body Surface ◽  
Refractory Period ◽  
Pulse Width ◽  
Closed Loop ◽  
The Body ◽  
Swine Model ◽  
Absolute Refractory Period ◽  
The Absolute

Background: Repolarization alternans (RA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death. Methods: We have developed a real-time, closed-loop system to record and analyze RA from multiple intracardiac leads, and deliver dynamically R-wave triggered pacing stimuli during the absolute refractory period. We have evaluated the ability of this system to control RA and reduce arrhythmia susceptibility, in vivo. Results: R-wave triggered pacing can induce RA, the magnitude of which can be modulated by varying the amplitude, pulse width, and size of the pacing vector. Using a swine model (n=9), we demonstrate that to induce a 1 µV change in the alternans voltage on the body surface, coronary sinus and left ventricle leads, requires a delivered charge of 0.04±0.02, 0.05±0.025, and 0.06±0.033 µC, respectively, while to induce a one unit change of the K score , requires a delivered charge of 0.93±0.73, 0.32±0.29, and 0.33±0.37 µC, respectively. For all body surface and intracardiac leads, both Δ(alternans voltage) and ΔK score between baseline and R-wave triggered paced beats increases consistently with an increase in the pacing pulse amplitude, pulse width, and vector spacing. Additionally, we show that the proposed method can be used to suppress spontaneously occurring alternans (n=7), in the presence of myocardial ischemia. Suppression of RA by pacing during the absolute refractory period results in a significant reduction in arrhythmia susceptibility, evidenced by a lower S rank score during programmed ventricular stimulation compared with baseline before ischemia. Conclusions: We have developed and evaluated a novel closed-loop method to dynamically modulate RA in a swine model. Our data suggest that suppression of RA directly reduces arrhythmia susceptibility and reinforces the concept that RA plays a critical role in the pathophysiology of arrhythmogenesis.

Hemodynamic impact of mitral prosthesis-patient mismatch on pulmonary hypertension: an in silico study

2008 ◽  
Vol 105 (6) ◽  
pp. 1916-1926 ◽  
Author(s):  
David Tanné ◽  
Lyes Kadem ◽  
Régis Rieu ◽  
Philippe Pibarot
Keyword(s):  
Pressure Gradient ◽  
Surface Area ◽  
Body Surface Area ◽  
Body Surface ◽  
Numerical Study ◽  
The Body ◽  
Effective Orifice Area ◽  
Cutoff Values ◽  
The Impact

Recent clinical studies reported that prosthesis-patient mismatch (PPM) becomes clinically relevant when the effective orifice area (EOA) indexed by the body surface area (iEOA) is <1.2–1.25 cm2/m2. To examine the effect of PPM on transmitral pressure gradient and left atrial (LA) and pulmonary arterial (PA) pressures and to validate the PPM cutoff values, we used a lumped model to compute instantaneous pressures, volumes, and flows into the left-sided heart and the pulmonary and systemic circulations. We simulated hemodynamic conditions at low cardiac output, at rest, and at three levels of exercise. The iEOA was varied from 0.44 to 1.67 cm2/m2. We normalized the mean pressure gradient by the square of mean mitral flow indexed by the body surface area to determine at which cutoff values of iEOA the impact of PPM becomes hemodynamically significant. In vivo data were used to validate the numerical study, which shows that small values of iEOA (severe PPM) induce high PA pressure (residual PA hypertension) and contribute to its nonnormalization following a valve replacement, providing a justification for implementation of operative strategies to prevent PPM. Furthermore, we emphasize the major impact of pulmonary resistance and compliance on PA pressure. The model suggests also that the cutoff iEOA that should be used to define PPM at rest in the mitral position is ∼1.16 cm2/m2. At higher levels of exercise, the threshold for iEOA is rather close to 1.5 cm2/m2. Severe PPM should be considered when iEOA is <0.94 cm2/m2 at rest.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

The Role of Computer Modeling in Electrocardiography

1990 ◽  
Vol 29 (04) ◽  
pp. 282-288 ◽  
Author(s):  
A. van Oosterom
Keyword(s):  
Electrical Activity ◽  
Computer Modeling ◽  
Body Surface ◽  
Electrical Current ◽  
The Body ◽  
Volume Conductor ◽  
Current Generator ◽  
Cardiac Electrical Activity ◽  
Source Models

AbstractThis paper introduces some levels at which the computer has been incorporated in the research into the basis of electrocardiography. The emphasis lies on the modeling of the heart as an electrical current generator and of the properties of the body as a volume conductor, both playing a major role in the shaping of the electrocardiographic waveforms recorded at the body surface. It is claimed that the Forward-Problem of electrocardiography is no longer a problem. Several source models of cardiac electrical activity are considered, one of which can be directly interpreted in terms of the underlying electrophysiology (the depolarization sequence of the ventricles). The importance of using tailored rather than textbook geometry in inverse procedures is stressed.

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