Selected scientific publications on diving medicine and physiology.

2010 Dec 10
The musculus pterygoïdeus proprius: an in-vivo approach with magnetic resonance imaging
Snoeck T1, Provyn S, Balestra C, Parlak B, Emonts P, Sesbouë B, Clarys JP.

There is a limited understanding of the normal function of the pterygoïdeus proprius muscle and the role that this muscle may have in temporomandibular disorders. Despite a well-described anatomical in-vitro approach to this muscle, there are still difficulties in investigating the fossa pterygopalatina. This study reveals an alternative in-vivo approach by magnetic resonance imaging to visualise the muscle in the fossa pterygopalatina on 78 head halves, describe the connections with the musculus temporalis and pterygoïdeus lateralis as well as report the incidence without dealing with the known inconveniences of the dissection approach. The results show an incidence of 12.82% for the musculus pterygoïdeus proprius equally divided between both genders. Two different types of bridging between the musculus temporalis and musculus pterygoïdeus lateralis were also found: (i) 'O' shape (6.41%) and (ii) 'Y' shape (6.41%). This study suggests the use of magnetic resonance imaging to investigate the different connections between vascular and muscular structures in the fossa pterygopalatina. Further research with this approach to link the appearance of the muscle with neurovascular entrapment syndromes is warranted.

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Acupuncture effect on thermal tolerance and electrical pain threshold: a randomised controlled trial
Amand M, Nguyen-Huu F, Balestra C.

OBJECTIVE: The aim of this study was to test whether acupuncture could modify the threshold of tolerance to thermal and electrical stimuli. METHODS: A randomised placebo-controlled single-blind trial was conducted in 36 healthy volunteers randomly distributed to control (no treatment), conventional acupuncture and sham acupuncture groups. The subjects were blind to the group allocation. The authors measured before and after treatment the pain threshold with the Painmatcher (Cefar Medical AB, Lund, Sweden) and the cold tolerance with the cold pressor test, together with the Visual Analogue Scale pain score.

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2011 Mar 2
Respiratory rate can be modulated by long-loop muscular reflexes, a possible factor in involuntary cessation of apnea
Balestra C, Levenez M, Lafère P, Dachy B, Ezquer M, Germonpré P.

INTRODUCTION: The main limiting factors determining apnea time are generally considered to be related to blood and cerebrospinal fluid chemistry. Several physiological (adaptive) mechanisms and some psychologic parameters, such as motivation, are also known to increase apnea time. AIM:We wished to study the link between peripheral muscle fatigue, the concomitant alteration of long latency (transcortical) reflexes and respiratory control. METHODS: Fatigue was induced in a small hand muscle (abductor pollicis brevis) (n = 11). This muscle is sufficiently small that its fatigue and the resulting production of metabolites are unlikely to alter whole-blood biochemistry. The Hoffmann reflex, an involuntary reaction to electrical stimulation of muscle afferent sensory fibreswas studied, as was the long latency reflex (LLR) using the Dueschl method in which electrical stimulation is superimposed on a slight voluntary contraction, Different fatiguing protocols were performed, and respiratory rate continuously recorded.

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2011 Jun 2
Passive flooding of paranasal sinuses and middle ears as a method of equalisation in extreme breath-hold diving
Germonpré P, Balestra C, Musimu P.

Breath-hold diving is both a recreational activity, performed by thousands of enthusiasts in Europe, and a high-performance competitive sport. Several 'disciplines' exist, of which the 'no-limits' category is the most spectacular: using a specially designed heavy 'sled,' divers descend to extreme depths on a cable, and then reascend using an inflatable balloon, on a single breath. The current world record for un-assisted descent stands at more than 200 m of depth. Equalising air pressure in the paranasal sinuses and middle-ear cavities is a necessity during descent to avoid barotraumas. However, this requires active insufflations of precious air, which is thus unavailable in the pulmonary system. The authors describe a diver who, by training, is capable of allowing passive flooding of the sinuses and middle ear with (sea) water during descent, by suppressing protective (parasympathetic) reflexes during this process. Using this technique, he performed a series of extreme-depth breath-hold dives in June 2005, descending to 209 m of sea water on one breath of air.

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2011 Apr 4
The normobaric oxygen paradox: a novel way to administer oxygen as an adjuvant treatment for cancer?
De Bels D, Corazza F, Germonpré P, Balestra C.

The "normobaric oxygen paradox" is a dual mechanism by which oxygen regulates the expression of the Hypoxia Inducible Factor 1 alpha (HIF-1α). The HIF-1α-depending gene regulation is responsible for many different genetic expressions including EPO and VEGF that are usually expressed in parallel. First, VEGF under-expression could decrease tumor angiogenesis leading to a decrease in tumor growth or even apoptosis of cancer cells. Second, induction of EPO-expression can provide cytoprotection. Altogether, this could be deleterious for cancer cells while helping non-malignant cells (at least neural and cardiac) cells to be protected from the side effects of chemotherapy. Eventually, HIF induction could boost immune response by inflammatory cells, increasing their antitumor activity.

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