Gene expression in acute Stanford type A dissection: a comparative microarray study

BACKGROUND: We compared gene expression profiles in acutely dissected aorta with those in normal control aorta. MATERIALS AND METHODS: Ascending aorta specimen from patients with an acute Stanford A-dissection were taken during surgery and compared with those from normal ascending aorta from multiorgan donors using the BD Atlas™ Human1.2 Array I, BD Atlas™ Human Cardiovascular Array and the Affymetrix HG-U133A GeneChip(®). For analysis only genes with strong signals of more than 70 percent of the mean signal of all spots on the array were accepted as being expressed. Quantitative real-time polymerase chain reaction (RT-PCR) was used to confirm regulation of expression of a subset of 24 genes known to be involved in aortic structure and function. RESULTS: According to our definition expression profiling of aorta tissue specimens revealed an expression of 19.1% to 23.5% of the genes listed on the arrays. Of those 15.7% to 28.9% were differently expressed in dissected and control aorta specimens. Several genes that encode for extracellular matrix components such as collagen IV α2 and -α5, collagen VI α3, collagen XIV α1, collagen XVIII α1 and elastin were down-regulated in aortic dissection, whereas levels of matrix metalloproteinases-11, -14 and -19 were increased. Some genes coding for cell to cell adhesion, cell to matrix signaling (e.g., polycystin1 and -2), cytoskeleton, as well as several myofibrillar genes (e.g., α-actinin, tropomyosin, gelsolin) were found to be down-regulated. Not surprisingly, some genes associated with chronic inflammation such as interleukin -2, -6 and -8, were up-regulated in dissection. CONCLUSION: Our results demonstrate the complexity of the dissecting process on a molecular level. Genes coding for the integrity and strength of the aortic wall were down-regulated whereas components of inflammatory response were up-regulated. Altered patterns of gene expression indicate a pre-existing structural failure, which is probably a consequence of insufficient remodeling of the aortic wall resulting in further aortic dissection

How to Survive 33 min after the Umbilical of a Saturation Diver Severed at a Depth of 90 msw?

In 2012, a severe accident happened during the mission of a professional saturation diver working at a depth of 90 m in the North Sea. The dynamic positioning system of the diver support vessel crashed, and the ship drifted away from the working place, while one diver’s umbilical became snagged on a steel platform and was severed. After 33 min, he was rescued into the diving bell, without exhibiting any obvious neurological injury. In 2019, the media and a later ‘documentary’ film suggested that a miracle had happened to permit survival of the diver once his breathing gas supply was limited to only 5 min. Based on the existing data and phone calls with the diver concerned (Dc), the present case report tries to reconstruct, on rational grounds, how Dc could have survived after he was cut off from breathing gas, hot water, light and communication while 90 m deep at the bottom of the sea. Dc carried bail-out heliox (86/14) within two bottles (2 × 12 L × 300 bar: 7200 L). Calculating Dc’s varying per-minute breathing gas consumption over time, both the decreased viscosity of the helium mix and the pressure-related increase in viscosity did not exhibit a breathing gas gap. Based on the considerable respiratory heat loss, the core temperature was calculated to be as low as 28.8 °C to 27.2 °C after recovery in the diving bell. In accordance with the literature, such values would be associated with impaired or lost consciousness, respectively. Relocating Dc on the drilling template by using a remotely operated vehicle (ROV), the transport of the victim to the bell and subsequent care in the hyperbaric chamber must be regarded as exemplary. We conclude that, based on rational arguments and available literature data, Dc’s healthy survival is not a miracle, as it can be convincingly explained by means of reliable data. Remaining with a breathing gas supply sufficient for five minutes only would not have ended in a miracle but would have ended in death by suffocation. Nevertheless, survival of such an accident may appear surprising, and probably the limit for a healthy outcome was very close. We conclude, in addition, that highly effective occupational safety measures, in particular the considerable bail-out heliox reserve, secured the healthy survival. Nevertheless, the victim’s survival is likely to be due to his excellent diving training, together with many years of diving routine. The rescue action of the second diver and Dc’s retrieval by the ROV operator are also suggestive of the behavior of carefully selected crew members with the high degree of professional qualification needed to correctly function in a hostile environment

Effects of Breath-Hold Deep Diving on the Pulmonary System

International audienc

Reply to Mankowska et al. Comment on “Muth et al. Assessing Critical Flicker Fusion Frequency: Which Confounders? A Narrative Review. <i>Medicina</i> 2023, <i>59</i>, 800”

First and foremost, we like to express our gratitude for the praise bestowed upon our narrative review [...

Review paper <br>Postconditioning: a brief review

Preconditioning represents the most effective form of cardioprotection that can be induced to attenuate the injury accompanying a longer lasting ischemia (=index ischemia) of sufficient duration and severity to cause myocardial necrosis. Preconditioning can be induced by short bouts of ischemia, several pharmaceuticals (e.g. adenosine), and volatile anesthetics all imposed before the index ischemia. A brief ischemia of an organ other than the heart can likewise initiate protection of the heart, which has been called “preconditioning at a distance” or “remote preconditioning”. According to the more recent literature, short bouts of ischemia after an index ischemia can also initiate cardioprotection, e.g. improved post-ischemic endothelial function, reduced infarct size and less apoptosis; this protective maneuver has been called “postconditioning”. Postconditioning can also be elicited at a distant organ, termed “remote postconditioning”. It is the aim of this short review to (1) characterize preconditioning and in particular postconditioning, (2) describe possible mechanisms, and (3) call attention to the clinical relevance of this cardioprotective strategy

“Lung packing” in breath hold-diving: An impressive case of pulmo–cardiac interaction

There is a complex interaction between the heart and the lungs. We report on a healthy female who performs breath hold diving at a high, international level. In order to optimize pressure equalization during diving and to increase oxygen available, apneists employed a special breathing maneuver, so called “lung packing”. Based on cardiac MRI we could demonstrate impressive effects of this maneuver on left ventricular geometry and hemodynamics. Beyond the fact, that our findings support the concept of pulmonary –cardiac interrelationship, it should be emphasized, that the reported, extreme breathing maneuver could have detrimental consequences due to reduction of stroke volume and cardiac output

An Updated Narrative Review on Ergometric Systems Applied to Date in Assessing Divers’ Fitness

Many recreational divers suffer medical conditions, potentially jeopardizing their safety. To scale down risks, medical examinations are mandatory and overwhelmingly performed using bicycle ergometry, which overlooks some important aspects of diving. Searching ergometric systems that better address the underwater environment, a systematic literature search was conducted using the keywords ‘diving’, ‘fitness’, ‘ergometry’, and ‘exertion’. All presented alternative systems found convincingly describe a greatly reduced underwater physical performance. Thus, if a diver’s workload in air should already be limited, he/she will suffer early from fatigue, risking a diving incident. How to assess fitness? Performance diagnostics in sports is always specific for a modality or movement. Therefore, professional scuba divers should be tested when fin-swimming underwater. For the vast number of recreational divers, the current screening can likely not be replaced. However, to prevent accidents, divers need to understand and be able to improve factors that limit their physical performance underwater. Other systems, presented here, will continue to be important tools in underwater research