Sight Search

Physics, Biophysics and Decompression Sickness

Jens-Christian Meiners studies tissue damage in spinal cord DCS.

Jens-Christian Meiners, Ph.D., a professor of physics and biophysics at the University of Michigan, focuses his laboratory’s research on mechanics of biological systems, primarily the dynamical properties of DNA and DNA–protein complexes. Meiners and his team are currently working on tissue mechanics and tissue damage through gas bubbles in the spinal cord, or spinal cord decompression sickness (DCS), which won him the 2019 DAN/R.W. “Bill” Hamilton Memorial Dive Medicine Research Grant.

Originally from Hanover, Germany, Meiners studied at the University of Konstanz and University of Bayreuth and graduated from the University of Delaware in 1997 with a master’s degree in physics. He returned to Germany to finish his doctoral degree in polymer physics on the micro and nanoscale using optical techniques and then accepted a postdoctoral position at California Institute of Technology (Caltech) in Pasadena, where his work started to encompass biophysics.
 
How did your career move into the biological side of physics?

Meiners: At Caltech we worked with single DNA molecules. With the technology of 20 years ago we could mechanically manipulate single DNA molecules using focused laser beams to pull them and change their structure. We wanted to understand how the topology of a DNA molecule affected the dynamics of the molecule, its interaction with other molecules like regulatory proteins and ultimately its biological functions. I got good at manipulating DNA and was even able to tie the molecules into knots — a feat that made a bit of a splash.
In 2000 I became an assistant professor of physics and biophysics at the University of Michigan. As my scientific focus continued to evolve, I became interested in the role of mechanics in biological processes. This approach became the overarching theme, initially with DNA and DNA–protein complexes and later with cellular mechanics. I looked at how mechanical tension in the DNA can turn genes on and off, for instance. I have since worked my way up through the ranks, which included seven years as chair of the biophysics department. After my tenure as chair ended, I was in charge of a well-established lab and had a secure position, so I started to look for what fun and interesting things I could do.

How did you get into diving and dive research?

I started diving about eight years ago, initially on a whim, during a surf trip to the Big Island of Hawai’i. We didn’t have any waves, but a dive shop was offering Discover Scuba dives on the reef, and that was it. I fell in love with diving and got certified. Soon I started to read the published literature on DCS and the proposed mechanisms. I didn’t find as much as I expected about the connection between bubbles, symptoms and the disease. What we started with was, “Bubbles form, [black box], you develop symptoms.” While there were some early studies in decompressed gels, they couldn’t make the connection to biological tissues. Then there were studies in decompressed live animals that showed empirically some tissue damage, but most of the findings didn’t answer my initial question about the mechanism behind it. Something in between was missing, so I decided to poke around, involve some undergraduate students in the project, and see if we could find more precise answers to what happens in that black box.

What was your approach to opening the black box?

We started on the molecular level but couldn’t find anything by looking at whether gas molecules could denature proteins during rapid decompression. Some proteins such as myoglobin have large gaps on the inside where we expect to see gas molecules. In X-ray crystallography, xenon gas in the molecules’ pockets are markers used to map the molecules. We thought that if we put in enough nitrogen or helium during compression that we might rupture the molecules during decompression, which could certainly cause a bad outcome. But despite very high pressures (100 atmospheres), nothing happened. It was a finding, but not the one we had anticipated.

The next approach was to look on the cellular scale for the mechanism that was killing the cells. The literature suggested that contact with micro gas bubbles can kill endothelial cells, but those are technically difficult experiments. We started by making gels and decompressing them to make bubbles form spontaneously, replicating early decompression experiments to see if our findings were the same. Our findings were a bit of an awakening: We saw the bubbles formed during decompression were tearing apart the gels. The understanding in the literature we had studied was that bubbles elastically deformed the gel or tissue, like a balloon inflating and deflating. According to this balloon model, things would eventually go back to their previous shape, meaning any tissue deformation would be reversible if you could shrink the bubbles, like in recompression therapy. This was not the case in our experiments.
 
Our hypothesis now was the permanent damage we observed in the gels would also happen in tissues. It’s comparable to small paper cuts caused by expanding bubbles in the tissue — the bubbles tear the tissue and do not just block blood flow through a reversible deformation.

Is this hypothesis the project for which you applied for DAN’s Hamilton research grant?

Yes, we wanted to look at what would happen in actual tissues and chose to work with the spinal cord, mostly due to the severity of reported symptoms and lasting impairment in spinal cord DCS. We used cow spinal cords as a model since they have mechanical properties that are reasonably close to human spinal cords and are readily available from a local butcher. We partnered with one of our MRI imaging experts, Joan Greve (who is also a diver), and built a small, experimental compression chamber that we could place inside the animal MRI scanner.
We got the data that we needed, and our analysis shows good support for our hypothesis that we see irreversible damage to the tissue. Whether it is tearing or a slow viscoelastic deformation, like what you see in Silly Putty, we can’t quite tell. Our experiments ended in an irreversible deformation of the tissue and contradicted the flexible balloon theory.

What is the next step after publishing these findings?

When we performed these experiments we also noticed that bubble formation was rare. We had to go through many samples to find a bubble, even though the profile we used was very aggressive. Saturating the tissue to 7 atmospheres over a day and then rapidly decompressing it led to minimal spontaneous bubble formation, which was surprising and led us to hypothesize that the missing ingredient, active circulation, may be responsible.
We believe that the key to damaging bubble formation is their nucleation process. Ordinarily, bubbles cannot form spontaneously, at least not easily, unless we are talking about a depth comparable to the Mariana Trench. We know very little about where the gas nuclei originate. Our hypothesis at this point is that nano- and micronuclei are constantly forming in the bloodstream, possibly in areas where a lot of flow and turbulence are present. These nuclei might be stable, and when they transport into the capillaries and the venous system, they experience lower pressure and begin to grow.

This hypothesis needs testing, but it is a reasonable explanation for the absence of large amounts of bubbles in our nonliving tissue samples. Additionally, we might be crushing some of those preexisting nuclei during the compression process in our experiments. The logical next step would be animal experiments to validate this hypothesis in vivo.

Are you working on the next steps?

We are equipped and eager to try it. We have all the facilities, but animal experiments need preparation, such as developing the protocols and applying for ethical approval and additional funding. Our goal is to get to a fundamental understanding of traumatic spinal cord injury mechanics from growing gas bubbles. Our hope is to improve treatment protocols for neurological DCS.

What do you do when you’re not performing physics or dive research?
Diving has become one of my greatest passions. I started diving relatively late, but after that initial Discover Scuba class, I got hooked and progressed quickly into more advanced diving. During a dive holiday in Mexico I tried cave diving — again more by chance than planning — and went through all the training. Those caves have become my favorite dive spots. If I had to pick one, it would probably be Cenote Caterpillar in Muyil, Mexico. I also dive locally in the Great Lakes. We have some beautiful shipwrecks, but I have discovered that I like rocks better than steel.
When I’m not diving, I enjoy all things outdoors, such as trail running or kayaking in the beautiful nature we have in Michigan. I’m also happy just firing up the grill in my backyard.



Categories

 2021
 April
Aqua Pool Noodle ExercisesUnderwater Photographer and DAN Member Madelein Wolfaardt10 Simple Things You Can Do to Improve Your Underwater PhotographyCOVID-19 and Diving: March 2021 UpdateDiver Return After COVID-19 Infection (DRACO): A Longitudinal AssessmentGuidelines for Lifelong Medical Fitness to DiveExperienceFitness Myth or Fitness Fact?The Safety of Sports for Athletes With Implantable Cardioverter-DefibrillatorsCardiovascular Fitness and DivingHypertensionPatent Foramen Ovale (PFO)Headaches and DivingMiddle-Ear Barotrauma (MEBT)O’Neill Grading SystemMask Squeeze (Facial Barotrauma)Sinus BarotraumaInner-Ear Barotrauma (IEBT)Middle-Ear EqualisationAlternobaric VertigoDecompression IllnessOn-Site Neurological ExaminationTreating Decompression Sickness (The Bends)Top 5 Factors That Increase Your Risk of the BendsHow to Avoid Rapid Ascents and Arterial Gas EmbolismUnintended Rapid Ascent Due to Uncontrolled InflationUnexpected Weight LossFlying After DivingWisdom Tooth Extraction and DivingYour Lungs and DivingScuba Diving and DiabetesDiving after COVID-19: What We Know TodaySwimmer’s Ear (Otitis Externa)Motion SicknessFitness for DivingDiving After Bariatric SurgeryWhen to Consult a Health-Care Provider Before Engaging in Physical ActivitiesFinding Your FitnessHealth Concerns for Divers Over 50Risk Factors For Heart DiseaseJuggling Physical Exercise and DivingSeasickness Prevention and TreatmentMember to Member: Guidelines for SeniorsHigh-Pressure OphthalmologyOver-the-Counter Medications
immersion and bubble formation Accidents Acid reflux Acute ailments After anaesthesia Air Quality Air exchange centre Air hose failure Air supply Airway control Air Alert Diver Magazine Alternative gas mix Altitude changes Altitude diving Altitude sickness Aluminium Oxide Ama divers Amino acids Anaerobic Metabolism Animal life Annual renewal Apnea Apnoea Aquatic life Aquatics and Scuba Diving Archaeology Arterial Gas Embolisms Arterial gas embolism Arthroscopic surgery Aspirin Aurel hygiene BCD BHP BLS BWARF Back adjustment Back pain Back treatment Backextensors Badages Bag valve mask Bahamas Balancing Bandaids Barbell back squat Barometric pressure Barotrauma Basic Life Support Batteries Becky Kagan Schott Bench press Benign prostate hyperplasia Benzophenones Beth Neale Beyond Standards Bilikiki Tours Biophysics Black Blood flow Blood thinners Blue Wilderness Blue economy Blurred vision Boat safety Boesmans gat Boesmansgat Bone fractures Bouyancy compensators Boyle's Law Boyle\'s Law Bradycardia Brain Breast Cancer Breath Hold Diving Breath holding Breath hold Breath-hold Breathing Gas Breathing gas contamination Breathing Breathold diving Bright Bank Broken bones Bruising Bubbleformation Buddy Exercise Buddy checks Buoyancy Burnshield CGASA CMAS CO2 COVID-19 Updates COVID-19 COVID CPR Cabin pressure Caissons diseas California Camera equipment Camera settings Cameras Cancer Remission Cancer treatments Cancer Cannabis and diving Cannabis Cape Town Dive Festival Cape Town Dive Sites Cape Town CapeTown Carbon Monoxide Carbon dioxide Cardio health Cardiological Cardiomyopathy Caribbean Carmel Bay Catalina Island Cave diving Challenging Environments Chamber Safety Chamber science Charging batteries Charles' Law Charles\' Law Charles\\\' Law Charles\\\\\\\' Law Charles\\\\\\\\\\\\\\\' Law Charlie Warland Chemotherapy Chest compressions Children diving Chiropractic Chlorophll Christina Mittermeier Citizen Conservation Cleaning products Closed Circuit Rebreathers Cmmunity partnership Coastalexcursion Cold Water Cold care ColdWater Cold Commercial Fishing Commercial diving Commercial schools Composition Compressed Air Compressed gas Consercation Conservation Photographer Conservation photography Conservation Contact lenses Contaminants Contaminated air Coral Conservation Coral Reefs Coral Restoration Coral bleaching CoralGroupers Corals Core strength Corona virus Coro Costamed Chamber Courtactions Cozumel Cristina Mittermeier Crohns disease Crowns Crystal build up Crystallizing hoses Cutaneous decompression Cylinder Ruptures Cylinder handwheel Cylinder valves DAN Courses DAN Profile DAN Researchers DAN medics DAN members DAN report DCI DCS Decompressions sickness DCS theories DCS DEMP DM training DNA DReams Dalton's Law Dalton\'s Law Dalton\\\'s Law Dalton\\\\\\\'s Law Dalton\\\\\\\\\\\\\\\'s Law Danel Wenzel Dangerous Marinelife Dauin island Dean's Blue Hole Dean\'s Blue Hole Deco dives Decompression Illness Decompression Sickness Decompression Stress Decompression illsnes Decompression treatment Decompression Decorator crabs Deep diving Deep water exploration Deepest SCUBA Dive Delayed Offgassing Dental Dever Health Diaphragms Diopter Diseases Disinfection Dive Buddy Dive Chamber Dive Computer Dive Destinations Dive H Dive Industry Dive Instruction Dive Instructor Dive Medical Form Dive Medical Dive Practices Dive Pros Dive Research Dive Safety Tips Dive South Africa Dive Training Dive Travel Wakatobi Dive Travel Dive accidents Dive buddies Dive computers Dive courses Dive excursions Dive exercise Dive experience Dive fitness Dive gear Dive heallth Dive health Dive medicals Dive medicines Dive medicine Dive operators Dive planning Dive procedures Dive safety 101 Dive safety Dive safe Dive skills Dive staff Dive travels DiveLIVE Diveleader training Diveleaders Diver Health Diver Profile Diver infliencers Diver on surface Divers Alert Divesites Diving Divas Diving Kids Diving Programs Diving Trauma Diving career Diving emergencies Diving emergency management Diving fit Diving guidelines Diving injuries Diving suspended Diving Dizziness Dolphins Domestic Donation Dowels Dr Rob Schneider Drift diving Drysuit diving Drysuit valves Drysuits Dyperbaric medicines EAPs EAP Ear pressure Ear wax Ears injuries Eco friendly Education Electronic Emergency action planning Emergency decompression Emergency plans Emergency underwater Oxygen Recompression Emergency Enviromental Protection Environmental factors Environmental impact Environmental managment Equalisation Equipment care Equipment failure Equipment inspection Evacuations Evacuation Evaluations Even Breath Exercise Exhaustion Exposure Protection Extended divetime Extinguisher Extreme treatments Eye injuries FAQ Factor V Leiden Failures FalseBay Diving Fatigue Faulty equipment Female divers Fetus development Fillings Fire Coral Fire Safety Firefighting First Aid Equipment First Aid Kit First Aid Training First Aid kits Fish Identification Fish Life Fish Fit to dive Fitness Training Fitness to dive Fitnesstrainng Fitness Flying Focus lights Foundations Fractures Francesca Diaco Francois Burman Fredive Free Student cover Free diving Free flow Freedive INstructor Freedive Training Freediver Freediving Instructors Freediving performance Freediving Gar Waterman Gas Density Gas consumption Gas laws Gas mixes GasPerformance Gases Gass bubbles Gastoeusophagus Gastric bypass Gastroenterologist Gear Servicing Germs Geyer Bank Giant Kelp Forest Giant Kelp Gobies Gordon Hiles Great White Sharks Guinness World Record Gutt irritations HCV HELP HIRA HMLI HMS Britanica Haemorhoid treatment Hazard Description Hazardous Marine life Hazardous marinelife Health practitioner Heart Attack Heart Health Heart Rate monitor Heart fitness Heart rates Heart rate Heart Heat stress Helium Hepatitis C Hepatitus B Hiatal Hernia High Pressure vessels High temperatures Hip strength Hip surgery Hippocampus History Hot Humans Hydrate Hydration Hydrogen Hydroids Hydrostatic pressure Hygiene Hyperbaric Chamber Hyperbaric research Hyperbarics Hypothermia Hypoxia I-52 found INclusivity IdentiFin Imaging Immersion Immine systems In Water Recompression Indemnity form Indian Ocean Indonesia Inert gas Infections Infra red Imaging Injections Inner ear Instinct Instruction Instructors Insurance Integrated Physiology International travel International Interval training Irritation Irukandji Syndrome Isotta housing Joint pain Junior Open Water Diver KZN South Coast Karen van den Oever Kate Jonker KateJonker Kidneys Kids scubadiver Komati Springs KwaZulu Natal Labour laws Lake Huron Laryngospasm Lauren Arthur Learning to dive Legal Network Legal advice Legislation Lembeh Straights Lenses Leukemis Liability Risks Liability releases Liability Life expectancy Lifestyle Lightroom editing Live aboard diving Liver Toxicity Liver diseas Liz Louw Lost at sea Low blood pressure Low pressure deterioration Low volume masks Lung Irritation Lung function Lung injuries Lung squeeze Lung surgery Lung MOD Macro photography Maintenance Malaria Mammalian Dive Response Mammalian effect Mandarin Fish Marine Biology Marine Science Marine Scientists Marine conservation Marine parks Marinelife Masks Master scuba diver Maximum operating depth Medical Q Medical emergencies Medical questionaire Medical statement Medicalresearch Medication Mehgan Heaney-Grier Mermaid Danii Mesophotic Michael Aw Middle ear pressure Mike Bartick Military front press Misool Resort Raja Ampat Mixed Gas Mono Fins Mooring lines More pressure Motion sickness Mozambique Muscle pain Mycobacterium marinum National Geographic Nausea Nautilus Ndibranchs Neck pain Neoprene layers Neuro assessments Neurological assessments Nitrogen Narcosis Nitrogen build up Nitrox No-decompression Non-nano zinc oxide Non-rebreather Mask Nonrebreather masks Normal Air North Sulawesi Nosebleeds Nuno Gomes O2 providers O2 servicing OOxygen maintenance Ocean Projects Ocean Research Ocean pollution Oil contamination Open water divers Optical focus Orbital implants Oronasal mask Osteonecrosis Out and about Out of air Outer ears Outreach Overhead Envirenments Oxygen Administration Oxygen Cylinder Oxygen Units Oxygen deficit Oxygen deicit Oxygen dificiency Oxygen ears Oxygen equipment Oxygen masks Oxygen supplies Oxygen supply Oxygen systems Oxygen therapy Oxygen P J Prinsloo PADI Freedivers PFI PJP Tech Parentalsupervision Part 3 Partner Training Perspective Philippine Islands Philippines Phillipines Photographers Photography tips Photography Physical Fitness Physioball Physiology Physiotherapy Pills Pistons Planning Plastic Pneumonia Pneumothorax Poison Pollution Pool Diving Pool workout Post-dive Pre-dive Predive check Pregnancy Pregnant divers Preparation Prepared diver Press Release Preventions Professional rights Provider course Psycological Pulmanologist Pulmonary Barotrauma Pulmonary Bleb Pulmonary Edema Pulse Punture wounds Pure Apnea Purge RAID South Africa RCAP REEF Radio communications Range of motion Rashes Rebreather diving Rebreatherdive Rechargeable batteries. Recompression chamber Recompression treatment Recompression Recycle Reef Chcek Reef Conservation Reef safe Reef surveyors Refractive correction Regulator failure Regulators Regulator Remote areas Renewable Report incidents Rescue Divers Rescue Procedure Rescue breathing Rescue breaths Rescue training Rescue Resume diving Return To Diving Return to diving Risk Assessments Risk assesments Risk assessment Risk elements Risk management Roatan Marine Park Roatan SABS 019 SMB SafariLive Safety Gear Safety Stop Safety SaherSafe Barrier Salty Wanderer Sanitising Sara Andreotti Sardine Run Saturation Diving Save our seas Schrimps Science Scombroid Poisoning Scuba Air Quality Scuba Guru Scuba Injury Scuba Instructor Scuba children Scuba dive Scuba education Scuba health Scubalearners Scubalife Sea Horses Sea slugs Sealife Sea Shallow dives Shark Protection Shark Research Shark conservation Shark diving Sharks Shipwrecks Shoulder strength Sideplank Signs and Symptoms Sit-ups Skin Bends Skin outbreak Skin rash Snorkeling Snorkels Social Distancing Sodwana Bay Solomon Islands Sonnier bank South Africa Spinal bends Spinal cord DCS Spinal pain Splits Squeezes Squid Run Stability exercise Standars Stay Fit Stents Step ups Stephen Frink Stepping up Strobe Lighting Stroke Submerge tech Submerged Sudafed Sulawesi Sun protection Sunscreen Supplemental oxygen Surface Marker Buoys Surface supplied Air Surfaced Surgeries Surgery Suspension training Symbiosis TRavel safety Tabata protocol Talya Davidoff Tattoes Tec Clark Technical Diving Technical divng The Bends The greatest Shoal The truth Thermal Notions Thunder Bay National Marine Sanctuary Tides Tips and trick Tooth squeeze Transplants Travel smarter Travel tips Travel Tropical Coastal Management Tunnelling Tweezers Ultrsound Umkomaas Unconsciousness Underground work Underseaa world Underwaater Photos Underwater floral Gardens Underwater hockey Underwater photographer Underwater photography Underwater pho Underwater University of Stellenbosch Urinary retention. Vaccines Vagus nerve Valsalva manoeuvers Valve stem seals Vape Vaping Vasopressors Vasvagal Syncope Venting Verna van Schak Virus infections Volatile fuels WWII wrecks War stories Washout treatments Wastewater Watchman device Water Resistance Water Weakness Weigang Xu Weights West Papua Western Cape Diving Wet Lenses Wet diving bell Wetsuit fitting Wetsuites Wetsuits White balance Wide Angle Photos Wide angles Wildlife Winter Wits Underwater Club Woman in diving Womans health Woman Women In Diving SA Women and Diving Women in diving Womens health Work of Breathing Workout World Deeepst Dive Record World Records Wound dressings Wreck divers Wreck dive Wreck diving Wreckdiving Wrecks Yoga Youth diver Zandile Ndholvu Zoology abrasion absolute pressure acoustic neuroma excision adverse seas air-cushioned alert diver altitude alveolar walls anemia antibiotics anticoagulants antiseptics bandages barodontalgia bent-over barbell rows bioassays body art breathing air calories burn carbon dioxide toxicity cardiovascular cerebrospinal fluid cervical spine checklist chemo port children child chronic obstructive pulmonary disease clearances closed circuit scuba corrective lenses currents cuts dead lift decompression algorithms decongestants decongestion dehydration dive injuries dive medicing dive ready child dive reflex dive tribe diver in distress diver rescue diver training dive diving attraction doctors domestic travel dri-suits drowning dry mucous membranes dry suits dry e-cigarettes ear spaces elearning electrolyte imbalance electroytes emergency action plans emergency assessment emergency training environmentally friendly equalising equalizing exposure injuries eyes fEMAL DIVERS fire rescue fitnes flexible tubing frediving freedivers gas bubble gas poisoning gastric acid gene expression health heartburn histidine hospital humidity immersion and bubble formation immersion pulmonary edema (IPE informal education isopropyl alcohol jaundice join DAN knee laparoscopic surgery longevity lower stress malaise marielife marine pathogens medical issues medical procedures medical risk assesment medications mental challenge mental preparedness micro-organisims micro minor illness mucous membranes nasal steroids nasal near drowning nematocysts neurological newdivers nitrogen bubbles off-gassed operating theatre operations orthopeadic otitis media outgas pain perforation phillippines phrenic nerve physical challenges pinched nerves plasters pneumoperitoneum polyester-TPU polyether-TPU post dive posture prescription mask preserve prevention proper equalization psychoactive pulmonary barotrauma. pulmonary injury. pulmunary barotrauma radiation rebreather mask rebreathers retinal detachment risk areas safety stops saturation scissors scuba equipment scuba single use sinus infections smoking snorkeling. spearfishing sterilising stings strength sub-aquatic sunscreen lotion swimmers ears tattoo care tecnical diver thermal protection tissue damage toxicity training trimix unified standards upwelling vision impaired warmers water quality zinc oxide