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

Conditions on Early Earth02:06

Conditions on Early Earth

Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
What is Evolutionary History?02:35

What is Evolutionary History?

Scientists record evolutionary history by analyzing fossil, morphological, and genetic data. The fossil record documents the history of life on Earth and provides evidence for evolution. However, both fossil and living organisms offer evidence that outlines Earth’s evolutionary history.
Conditions on Early Earth02:06

Conditions on Early Earth

Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
Eukaryotic Evolution01:24

Eukaryotic Evolution

The endosymbiont theory is the most widely accepted theory of eukaryotic evolution; however, its progression is still somewhat debated. According to the nucleus-first hypothesis, the ancestral prokaryote first evolved a membrane to enclose DNA and form the nucleus. Conversely, the mitochondria-first hypothesis suggests that the nucleus was formed after endosymbiosis of mitochondria.
Contrary to the endosymbiont theory, the eukaryote-first hypothesis proposes that the simpler prokaryotic and...
First Pass Effect01:12

First Pass Effect

Presystemic elimination, or the first-pass effect, is the metabolism of drugs that reduces their effective concentration at the site of action. Apart from the first-pass effect, the systemic bioavailability of the drug is also reduced by other factors, including incomplete absorption or chemical degradation of drugs.
Depending on the route of administration, drugs can be metabolized in the liver, intestine, lungs, and vasculature. Orally administered drugs are first absorbed through the...
Emerging Adulthood01:27

Emerging Adulthood

Jeffrey Arnett's concept of emerging adulthood offers a framework to understand the unique developmental stage between adolescence and full-fledged adulthood, generally from ages 18 to 25. This period is marked by extensive exploration and shifts in identity, relationships, and career choices, a process known in psychology as role experimentation. Emerging adulthood reflects the evolving cultural expectations surrounding adulthood and the dynamic process of personal transformation during this...

You might also read

Related Articles

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

Sort by
Same author

Pregnancy-related pulmonary embolism: Clinical characteristics, management and outcomes in a South African academic hospital.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2026
Same author

Venous thromboembolism prevention in South Africa: Bridging the gap between guidelines and practice.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2025
Same author

Clot twist - D-dimer analysis of healthy adults receiving heterologous or homologous booster COVID-19 vaccine after a single prime dose of Ad26.COV2.S in a phase II randomised open-label trial, BaSiS.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2025
Same author

The Use of venous thromboembolism prophylaxis in relatioN to patiEnt risk profilINg (TUNE IN) Wave 3 study.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2025
Same author

Thrombosis and bleeding outcomes with warfarin conversion to rivaroxaban during the COVID-19 pandemic.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2025
Same author

Pulmonary ultrasound in COVID-19 and non-COVID-19 pneumonia in South Africa: An observational study.

African journal of thoracic and critical care medicine·2025
Same journal

SAMA Health Summit Abstracts.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2026
Same journal

On behalf of the South African Medical Association (SAMA), The Scientific Committee of the SAMA Health Summit, is pleased to pesent this abstract issue, showcasing the posters and oral presentations delivered at the Summit, which was held from 22-24 May 2026.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2026
Same journal

Proceedings of the 2<sup>nd</sup> Data Driven Surgery Conference (DDSC 2025).

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2026
Same journal

Clinical practice guidelines for the management of fever and neutropenia in South African children and adolescents with cancer.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2026
Same journal

The changing fortunes of the District Health System in SA (1994 - 2020): A retrospective review.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2026
Same journal

Thomas Micheal Guntram Ignaz Rehle (1951 - 2025).

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2026
See all related articles

Related Experiment Video

Updated: May 13, 2026

Methods to Test Visual Attention Online
09:44

Methods to Test Visual Attention Online

Published on: February 19, 2015

11.8K

Early Online.

B F Jacobson1, S Louw2, E Schapkaitz3

  • 1National Health Laboratory Service and Department of Haematology and Molecular Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. clot@nhls.ac.za.

South African Medical Journal = Suid-Afrikaanse Tydskrif Vir Geneeskunde
|July 23, 2024
PubMed
Summary
This summary is machine-generated.

Air travel at high altitude can cause blood to clot more easily in healthy individuals. Further studies are needed to determine if blood clot prevention medication can reduce this risk.

More Related Videos

Online Explorative Study on the Learning Uses of Virtual Reality Among Early Adopters
07:29

Online Explorative Study on the Learning Uses of Virtual Reality Among Early Adopters

Published on: November 22, 2019

8.2K
Interactive and Visualized Online Experimentation System for Engineering Education and Research
08:35

Interactive and Visualized Online Experimentation System for Engineering Education and Research

Published on: November 24, 2021

2.4K

Related Experiment Videos

Last Updated: May 13, 2026

Methods to Test Visual Attention Online
09:44

Methods to Test Visual Attention Online

Published on: February 19, 2015

11.8K
Online Explorative Study on the Learning Uses of Virtual Reality Among Early Adopters
07:29

Online Explorative Study on the Learning Uses of Virtual Reality Among Early Adopters

Published on: November 22, 2019

8.2K
Interactive and Visualized Online Experimentation System for Engineering Education and Research
08:35

Interactive and Visualized Online Experimentation System for Engineering Education and Research

Published on: November 24, 2021

2.4K

Area of Science:

  • Aviation Medicine
  • Hematology
  • Physiology

Background:

  • Long-haul flights increase the risk of aviation-related thrombosis (ART) by two to fourfold.
  • Previous research explored how hypoxia, dehydration, and immobility during air travel affect hemostasis.
  • This study specifically investigates high altitude's role in ART risk.

Purpose of the Study:

  • To determine if high altitude exposure during air travel contributes to a hypercoagulable state.
  • To assess changes in hemostatic markers and hydration status in response to simulated high-altitude flight.

Main Methods:

  • Forty healthy volunteers were exposed to simulated altitude of 18,000 feet for 1 hour in an unpressurized aircraft.
  • Oxygen saturation was maintained above 92% with supplemental oxygen.
  • Blood and urine samples were collected pre- and post-flight to measure D-dimer, thromboelastography (TEG) parameters, von Willebrand factor (VWF) activity, and urine osmolality.

Main Results:

  • Significant changes (p<0.001) were observed in D-dimer levels, VWF activity, urine osmolality, and TEG parameters (R time, K time, MA) post-flight.
  • Urine osmolality showed a positive correlation with VWF activity (r=0.469; p<0.002).

Conclusions:

  • High-altitude air travel induces a hypercoagulable state in healthy individuals.
  • Further research is recommended to evaluate the efficacy of thromboprophylaxis in mitigating coagulation activation during high-altitude flights.