Loop Model
Loop Model - Related Videos
04:58
Mouse Ileal Loop Model: A Surgical Model to Study Intestinal Permeability in the Mouse
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2025
This video demonstrates the generation of an ileal loop model to study intestinal permeability in a mouse model. This method provides a live model to understand the epithelial barrier function and consequent immune response.
17:15
Catheterization of Intestinal Loops in Ruminants
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Cited by 4 •
2009
We describe a novel surgical method for catheterizing 'intestinal loops' within the ileum of sheep. Once animals have recovered from surgery and have cleared antibiotics and analgesics, multiple treatments can be deposited directly in loops via the catheters.
08:53
The Arteriovenous (AV) Loop in a Small Animal Model to Study Angiogenesis and Vascularized Tissue Engineering
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Cited by 38 •
2016
We describe a microsurgical approach for the generation of an arteriovenous (AV) loop as a model for analyzing vascularization in vivo in an isolated and well-characterized environment. This model is not only useful for the investigation of angiogenesis, but is also optimally suited for engineering axially vascularized and transplantable tissues.
07:56
Closed Chest Biventricular Pressure-Volume Loop Recordings with Admittance Catheters in a Porcine Model
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Cited by 9 •
2021
Here we present a closed chest approach to admittance-based bi-ventricular pressure-volume loop recordings in pigs with acute right ventricular dysfunction.
06:16
Tracking Fibrinolysis of Chandler Loop-Formed Whole Blood Clots Under Shear Flow in An In-Vitro Thrombolysis Model
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2024
In-vitro thrombolysis assays have often struggled to replicate in-vivo conditions whether in the model thrombus being digested or in the environment in which thrombolysis is occurring. Herein, we explore how coupling the Chandler loop and Real-Time Fluorometric Flowing Fibrinolysis Assay (RT-FluFF) is used for high-fidelity, ex-vivo, clot lysis monitoring.
FAQs
In a Loop Model, positive feedback strengthens a response by allowing an output to promote later activity in the sequence. Negative feedback has the opposite effect: the output counteracts or reduces subsequent activity. These contrasting relationships help explain whether a biological system amplifies a change or limits it. Distinguishing the feedback direction is essential for interpreting regulation and predicting behavior over time.
Variables represent changing features of the biological process, while connected steps show how one stage relates to another. Together, they identify which outputs can influence later stages or earlier points in the sequence. This organization makes complex interactions easier to examine, because researchers can focus on specific relationships and consider how altering one part might affect the rest of the system.
The outcome depends on how feedback relationships shape activity across successive stages. Limiting feedback can support a stable state, whereas recurring changes in activity can produce oscillations over time. Strengthening feedback can amplify a response. A Loop Model therefore helps connect the structure of interactions with the broader behavior observed in a biological system.
Construction begins by identifying the relevant biological steps and variables, then arranging them as connected relationships. Outputs are linked to the later or earlier stages they influence, and the feedback direction is marked as positive or negative when supported by the process being studied. The resulting pathway can then be examined for predicted behavior and compared with observations.
Researchers can compare observed changes with the relationships represented in the model. If the data show amplification, limitation, stability, or recurring fluctuations, those outcomes can indicate whether the proposed feedback connections are plausible. Because the model simplifies a complex process into testable pathways, it also helps researchers develop hypotheses about responses to changing conditions.
The framework can provide context for homeostasis, gene regulation, and cell signaling, as well as other biological processes involving interacting stages and feedback. In homeostasis, it can clarify regulation toward a stable state; in gene regulation or signaling, it can organize relationships among process components. Its value lies in linking these interactions to measurable system behavior.