Effects of HZE particle on the nigrostriatal dopaminergic system in a future Mars mission

Because of long duration travel outside the Earth's magnetic field, the effect of iron-rich high charge and energy (HZE) particles in Galactic Cosmic Rays on human body is the major concern in radiation protection. Recently attention has been directed to effects on the central nervous system in addition to mutagenic effects. In particular, a reduction in striatal dopamine content on nigrostriatal dopaminergic system has been reported by investigators using accelerated iron ions in ground-based mammalian studies. In addition, studies of the pathophysiology of Parkinson's disease demonstrated that excess iron cause a reduction in the dopamine content in the substantia nigra. This suggests an intriguing possibility to explain the selective detrimental effects of HZE particles on the dopaminergic system. Should these particles have biochemical effects, possible options for countermeasures are: (1) nutritional prevention, (2) medication, and (3) surgical placement of a stimulator electrode at a specific anatomic site in the basal ganglia.

Effect of caffeine consumption on tissue oxygen levels during hyperbaric oxygen treatment

Ten men were exposed to hyperbaric oxygen (HBO2), and their tissue oxygen levels were monitored after they drank either placebo or caffeine beverages. Transcutaneous tissue oxygen (PtcO2) monitor measurements in a normobaric air environment were initially obtained from transducers on the subject's chest and foot. The subjects then consumed either the caffeine (3 mg.kg-1) or the placebo beverage, and after 20 min the subjects were pressurized in a hyperbaric chamber to 2.36 atm abs (1 atm = 101.3250 kPa). The test subjects began breathing 100% oxygen at 2.36 atm abs, 30 min after administration of the experimental beverage, and continued for 30 min, after which the final chest and foot PtcO2 measurements were recorded (1 h after ingestion of the test drink). Each subject underwent a second hyperbaric exposure during which the alternate drink was administered (either the placebo or the caffeine), and PtcO2 measurements were again obtained. The increase in right foot PtcO2 values during HBO2 exposure was significantly smaller after caffeine consumption than after placebo (P = 0.0018).

Pneumomediastinum during flight secondary to facial fractures--a case report

A case of inflight cervical emphysema and pneumomediastinum secondary to a "blowout" fracture of the right lateral orbit and maxillary sinus is described. A 43-yr-old male was struck on the face by another passenger during a flight from Australia to Greece. The cause of the emphysema and its fast progression is discussed with respect to the anatomic relations of the facial and cervical subcutaneous space and the mediastinum. The injured passenger was treated 3 h after arrival in Thessaloniki, Greece. This case demonstrates a potential complication of a "blowout" orbital fracture during flight. The condition should be recognized by emergency department personnel with the patient kept under observation and symptomatic treatment initiated. Prophylactic antibiotics should be considered.