Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Glucose Absorption Into the Small Intestine01:26

Glucose Absorption Into the Small Intestine

34.0K
Complex carbohydrates consumed cannot be absorbed into the small intestine in their original form. First, they must be hydrolyzed to a monosaccharide form such as glucose or galactose. These monosaccharides are then transported across the intestinal membrane and into the blood via transcellular transport. The intestinal epithelial cells allow the movement of these monosaccharides with a defined 'entry' through membrane transporter proteins present on their apical membrane and...
34.0K
Methods for Studying Drug Absorption: In vitro01:16

Methods for Studying Drug Absorption: In vitro

844
In vitro experiments are crucial for understanding the transport and absorption of drugs through biological materials. These studies employ varied methods such as the diffusion cell method, the everted sac technique, and the everted ring technique.
The diffusion cell method uses a two-compartment cell, including a donor compartment with the drug solution, which simulates the environment where the drug is applied, and a receptor compartment with a buffer solution, which simulates the environment...
844
Methods for Studying Drug Absorption: In situ01:09

Methods for Studying Drug Absorption: In situ

887
In situ experiments, such as the Doluisio method and Single-Pass Perfusion technique, provide critical insights into drug uptake by simulating in vivo conditions for drug absorption.
The Doluisio method involves perfusing a prepared segment of a rat's small intestine with a solution of radiolabeled drug and a non-absorbable marker. This helps to differentiate between absorbed and non-absorbed drug concentrations. The intestinal segment is connected at both ends using tubing and syringes,...
887
One-Compartment Open Model: Wagner-Nelson and Loo Riegelman Method for ka Estimation01:24

One-Compartment Open Model: Wagner-Nelson and Loo Riegelman Method for ka Estimation

1.5K
This lesson introduces two critical methods in pharmacokinetics, the Wagner-Nelson and Loo-Riegelman methods, used for estimating the absorption rate constant (ka) for drugs administered via non-intravenous routes. The Wagner-Nelson method relates ka to the plasma concentration derived from the slope of a semilog percent unabsorbed time plot. However, it is limited to drugs with one-compartment kinetics and can be impacted by factors like gastrointestinal motility or enzymatic degradation.
On...
1.5K
Measurement of Bioavailability: Pharmacokinetic Methods01:30

Measurement of Bioavailability: Pharmacokinetic Methods

517
Pharmacokinetics is a vital branch of pharmacology that examines how drugs are absorbed, distributed, metabolized, and excreted by the body. Two key methodologies in pharmacokinetics are plasma drug concentration studies and urinary drug excretion analyses, both of which provide critical insights into a drug's therapeutic efficacy and bioavailability.Plasma Drug Concentration-Time StudiesPlasma drug concentration-time studies involve analyzing blood samples at specific intervals to quantify...
517
Measurement of Bioavailability: Pharmacodynamic Methods01:20

Measurement of Bioavailability: Pharmacodynamic Methods

1.0K
Pharmacodynamic methods provide insights into a drug's effects on physiological processes over time and play a crucial role in understanding bioavailability and therapeutic efficacy. These methods can be broadly classified into acute pharmacological and therapeutic response approaches, each with distinct mechanisms and applications.The acute pharmacological response method directly correlates a drug's physiological effects, such as ECG or pupil diameter changes, to its time course in the body.
1.0K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Sulphide quinone reductase contributes to hydrogen sulphide metabolism in murine peripheral tissues but not in the CNS.

British journal of pharmacology·2011
Same author

Risk factors for severe delayed postpolypectomy bleeding.

Endoscopy·2008
Same author

FOBT is not an effective way to screen for gastric cancer.

Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver·2007
Same author

Quality in the technical performance of screening flexible sigmoidoscopy: recommendations of an international multi-society task group.

Gut·2005
Same author

Colon polyps and cancer.

Endoscopy·2005
Same author

Update on colorectal polyps: management and follow-up surveillance.

Endoscopy·2003

Related Experiment Video

Updated: Apr 30, 2026

Measuring Lactase Enzymatic Activity in the Teaching Lab
04:41

Measuring Lactase Enzymatic Activity in the Teaching Lab

Published on: August 6, 2018

117.2K

Quantitative measurement of lactose absorption.

J H Bond, M D Levitt

    Gastroenterology
    |June 1, 1976
    PubMed
    Summary

    Pulmonary hydrogen (H2) excretion is the most accurate indirect method for quantifying lactose malabsorption, correlating well with direct ileal measurements. Other methods like (14)CO2 and stool excretion are less reliable for assessing lactose absorption.

    Area of Science:

    • Gastroenterology
    • Nutritional Science
    • Biochemistry

    Background:

    • Lactose malabsorption affects a significant portion of the global population.
    • Accurate quantification of unabsorbed lactose is crucial for understanding its clinical effects.
    • Existing indirect methods for assessing lactose absorption vary in reliability.

    Purpose of the Study:

    • To compare the accuracy of three indirect methods (pulmonary H2, pulmonary (14)CO2, stool (14)C excretion) for quantifying lactose malabsorption.
    • To validate these indirect methods against direct measurements from ileal aspirates.
    • To explore factors contributing to individual differences in diarrhea susceptibility among lactase-deficient individuals.

    Main Methods:

    • Ingestion of 1-(14)C-lactose and polyethylene glycol (PEG) by normal and lactase-deficient subjects.

    More Related Videos

    Analysis of Fucosylated Human Milk Trisaccharides in Biotechnological Context Using Genetically Encoded Biosensors
    10:17

    Analysis of Fucosylated Human Milk Trisaccharides in Biotechnological Context Using Genetically Encoded Biosensors

    Published on: April 13, 2019

    5.7K
    Author Spotlight: Experiential Tool for Teaching Active Transport Using Ex Vivo Histidine Uptake
    04:40

    Author Spotlight: Experiential Tool for Teaching Active Transport Using Ex Vivo Histidine Uptake

    Published on: October 4, 2024

    2.3K

    Related Experiment Videos

    Last Updated: Apr 30, 2026

    Measuring Lactase Enzymatic Activity in the Teaching Lab
    04:41

    Measuring Lactase Enzymatic Activity in the Teaching Lab

    Published on: August 6, 2018

    117.2K
    Analysis of Fucosylated Human Milk Trisaccharides in Biotechnological Context Using Genetically Encoded Biosensors
    10:17

    Analysis of Fucosylated Human Milk Trisaccharides in Biotechnological Context Using Genetically Encoded Biosensors

    Published on: April 13, 2019

    5.7K
    Author Spotlight: Experiential Tool for Teaching Active Transport Using Ex Vivo Histidine Uptake
    04:40

    Author Spotlight: Experiential Tool for Teaching Active Transport Using Ex Vivo Histidine Uptake

    Published on: October 4, 2024

    2.3K
  • Measurement of pulmonary H2 and (14)CO2 excretion, and stool (14)C excretion.
  • Direct quantification of unabsorbed lactose using the (14)C:PEG ratio in terminal ileal aspirates.

    • Main Results:

    • Ileal aspiration revealed 0-8% unabsorbed lactose in normals and 42-75% in lactase-deficient subjects.
    • Pulmonary H2 excretion showed the highest correlation (r=0.94) with direct ileal measurements.
    • Pulmonary (14)CO2 excretion and stool (14)C:PEG ratios were less accurate in quantifying lactose malabsorption.

    Conclusions:

    • Pulmonary H2 excretion is a reliable, non-invasive method for assessing lactose absorption.
    • Differences in unabsorbed lactose quantity and colonic metabolism may explain varying diarrhea susceptibility.
    • Endogenous electrolytes contribute significantly to the osmotic load delivered to the colon.