Negative neurofunctional effects of frequency, depth and environment in recreational scuba diving: the Geneva "memory dive" study.

OBJECTIVES: To explore relationships between scuba diving activity, brain, and behaviour, and more specifically between global cerebral blood flow (CBF) or cognitive performance and total, annual, or last 6 months' frequencies, for standard dives or dives performed below 40 m, in cold water or warm sea geographical environments. METHODS: A prospective cohort study was used to examine divers from diving clubs around Lac Léman and Geneva University Hospital. The subjects were 215 healthy recreational divers (diving with self-contained underwater breathing apparatus). Main outcome measures were: measurement of global CBF by (133)Xe SPECT (single photon emission computed tomography); psychometric and neuropsychological tests to assess perceptual-motor abilities, spatial discrimination, attentional resources, executive functioning, and memory; evaluation of scuba diving activity by questionnaire focusing on number and maximum depth of dives and geographical site of the diving activity (cold water v warm water); and body composition analyses (BMI). RESULTS: (1) A negative influence of depth of dives on CBF and its combined effect with BMI and age was found. (2) A specific diving environment (more than 80% of dives in lakes) had a negative effect on CBF. (3) Depth and number of dives had a negative influence on cognitive performance (speed, flexibility and inhibition processing in attentional tasks). (4) A negative effect of a specific diving environment on cognitive performance (flexibility and inhibition components) was found. CONCLUSIONS: Scuba diving may have long-term negative neurofunctional effects when performed in extreme conditions, namely cold water, with more than 100 dives per year, and maximal depth below 40 m.

Experimental bilateral lobar lung transplantation and its application in humans.

BACKGROUND: The critical lack of donor organs from people of small size or children has created great difficulties in transplantation for recipients who are of smaller size. Surgical techniques of organ reduction and partial transplantation may to some extent solve the problem of disparity in organ size, be it liver or lung, and lessen the problem of scarcity of paediatric organs. METHODS: In a series of experiments on dogs the surgical technique of pulmonary partition of a large organ from a grown dog followed by transplantation of lobes, either unilaterally or bilaterally, into a young dog was studied. Two series of experiments were performed in two groups of animals; in group 1 transplantation of a single right lobe (n = 6) or single left lobe (n = 6) from a split adult lung was carried out and in group 2 (n = 10) animals received bilateral lobar transplants from a single split adult lung. The animals were sacrificed at fixed intervals (days 8-120 in group 1, days 7-10 in group 2) and the results of the surgical technique were assessed. RESULTS: Healing of lobar bronchial anastomoses was found to be excellent with no histological evidence of dehiscence or ulceration. There was one bronchial anastomotic stenosis and one arterial thrombosis. Morphological and functional adaptation of the lobes in the thorax was found to be excellent in both groups of animals. The technique has been applied in a clinical setting and the first patient with bilateral lobar lung transplantation followed for 30 months is reported. CONCLUSION: Lung partition and subsequent lobar transplantation, either unilaterally or bilaterally, is associated with satisfactory early results in an animal experimental model. Initial clinical experience in one patient has been successful.

[Experimental model of pulmonary bipartition with bilateral lobe transplantation in dogs and application to clinical medicine]. / Mise au point expérimentale de la bipartition pulmonaire avec transplantation lobaire bilatérale chez le chien et application en clinique humaine.

The crucial need for donors of paediatric or small sized organs has been a great obstacle to overcome in organ transplantation in children or small adults. Some progress in adapting size of the donor organs has been achieved with surgical procedures for reducing the size of donor organs, partial transplantation (single lobe of the liver or the lung) and liver partition, offering a partial solution to the insufficient supply of paediatric organs. We propose an experimental model in the dog of lung partition associated with monolateral (series I) or bilateral (series II) lobe transplantation. The results have been encouraging both in terms of quality of healing and in morphological and functional adaptation of the transplanted lobes, allowing us to apply this technique of lung partition and bilateral lobe transplantation in human patients. The outcome has been excellent in the first case after 18 months follow-up.