Heterogeneous glyoxal oxidation: a potential source of secondary organic aerosol.

Laboratory studies are described that suggest reactive uptake of glyoxal on particulate containing HNO(3) could contribute to the formation of secondary organic aerosol (SOA) in the upper troposphere (UT). Using a Knudsen cell flow reactor, glyoxal is observed to react on supercooled H(2)O/HNO(3) surfaces to form condensed-phase glyoxylic acid. This product was verified by derivatization and GC-MS analysis. The reactive uptake coefficient, γ, of glyoxal varies only slightly with the pressure of nitric acid, from γ = 0.5 to 3.0 × 10(-3) for nitric acid pressures between 10(-8) and 10(-6) Torr. The data do not show any dependence on temperature (181-201 K) or pressure of glyoxal (10(-7) to 10(-5) Torr). Using the determined reactive uptake kinetics in a simple model shows that glyoxal uptake to supercooled H(2)O/HNO(3) may account for 4-53% of the total organic mass fraction of aerosol in the UT.

Differences in the response of a striped dolphin (Stenella coeruleoalba) and a harbour porpoise (Phocoena phocoena) to an acoustic alarm.

Small cetacean bycatch in gillnet fisheries may be reduced by deterring odontocetes from nets acoustically. However, different odontocete species may respond differently to acoustic signals from alarms. Therefore, in this study a striped dolphin and a harbour porpoise were subjected simultaneously to sounds produced by the XP-10 experimental acoustic alarm. The alarm produced 0.3s tonal signals randomly selected from a set of 16 with fundamental frequencies between 9 and 15kHz, with a constant pulse interval of 4.0s (duty cycle 8%) and a Source Level range of 133-163dB re 1muPa (rms). The effect of the alarm was judged by comparing the animals' respiration rate and position relative to the alarm during test periods with those during baseline periods. As in a previous study on two porpoises with the same alarm, the porpoise in the present study reacted strongly to the alarm by swimming away from it and increasing his respiration rate. The striped dolphin, however, showed no reaction to the active alarm. Based on harbour porpoise audiograms and the specific audiogram of the striped dolphin in the present study, and the low background noise levels during the experiment, both animals must have heard the alarm signals clearly. This study indicates that cetacean species are not equally sensitive to human-made noise disturbance. Therefore, source levels of acoustic alarms should be adapted to the species they are supposed to deter. In addition, alarms should be tested on each odontocete species for which they are intended to reduce bycatch.

[Patients of other cultures and somatization]. / Quand la parole ne fonctionne plus. Patients d'autres cultures et troubles somatoformes.

This work concerns my personal clinical experience with people of other cultures presenting somatization. I analyse different ways of understanding this apparent lack of words in some of these patients, and a clinical approach based on the conviction that words are necessary to alleviate suffering of our patients.

Effect of factors inhibiting HLA-DR antibodies before transplantation on kidney graft survival.

Blood transfusions administered before renal allografts are known to enhance graft survival. Among alternative hypotheses proposed to explain this effect, one of the most attractive is the possible induction of antiidiotypic antibodies directed against the specific antigen-binding site of donor-specific antibodies. In order to determine if such blocking antibodies are generated after blood transfusions, serial serum samples obtained before transplantation from 44 kidney recipients were analyzed for the development of HLA-DR alloantisera inhibitory activity by a microcytotoxicity inhibition assay. A significant correlation was found between the presence of inhibitory factors before transplantation and prolonged graft survival. However a clear relation between the development of inhibitory factors and the administration of transfusions could not be established. In addition the sera of 36 patients were studied for the presence of circulating immune complexes (CIC) before grafting. The presence of CIC was clearly associated with that of inhibitory factors, and with a prolonged graft survival. Thus these studies provide support for the development of blocking (possibly antiidiotypic) antibodies to anti-MHC in human renal graft recipients.

Detection distances of bottom-set gillnets by harbour porpoises (Phocoena phocoena) and bottlenose dolphins (Tursiops truncatus).

Many odontocetes die annually in gillnet fisheries. Why they become entangled is not yet clear. Maybe some species detect the nets too late to avoid collision. Therefore, the target strength of 11 types of bottom-set gillnets was measured under 0 and 45 degrees angles of incidence. From these target strengths and from knowledge on the echolocation abilities of two odontocete species (harbour porpoises, bottlenose dolphins), the detection ranges of the nets by these small cetaceans could be estimated. The 90% detection range by echolocating harbour porpoises, approaching the nets at right (perpendicular) angles under low noise level conditions, varied between 3 and 6 m depending on the net type. For bottlenose dolphins, under high noise conditions, the 90% detection range varied between 25 and 55 m. At other angles of approach, the estimated detection ranges are shorter. The study suggests that echolocating bottlenose dolphins can detect nets in time to avoid collision, whereas echolocating harbour porpoises cannot in most cases. Suggestions for future research to reduce small cetacean bycatch by improving the nets' detectability by echolocation are given.

The influence of three acoustic alarms on the behaviour of harbour porpoises (Phocoena phocoena) in a floating pen.

Harbour porpoise bycatch may be reduced by deterring porpoises from nets acoustically. In this study, two harbour porpoises were subjected to three acoustic alarms. The effect of each alarm was judged by comparing the animals' position and respiration rate during a test period with that during a baseline period. The XP-10 alarm produced 0.3 s tonal signals randomly selected from a set of 16 with fundamental frequencies between 9 and 15 kHz, with a constant pulse interval of 4.8 s (duty cycle 6%). The 2MP alarm produced 0.3 s tonal signals randomly selected from a set of 16 with similar fundamental frequencies but with random pulse intervals of between 2 and 5 s (duty cycle 8%). The frequency spectra and source levels of the 2MP and XP-10 alarms varied depending on the signal selected. The HS20-80 alarm produced a constant, but asymmetrical frequency modulated sinewave between 20 and 80 kHz with total pulse duration of 0.3 s. with random pulse intervals of between 2 and 5 s (duty cycle 4.6%). The porpoises reacted to all three alarms by swimming away from them and by increasing their respiration rate. The XP-10, which on average had the highest source level, had the strongest effect.

[The health of asylum seekers: from communicable disease screening to post-traumatic disorders]. / La santé des demandeurs d'asile: du dépistage des maladies transmissibles à celui des séquelles post-traumatiques.

As the end of this century approaches, the pressure of migration is increasing. It is difficult to limit with restrictive measures the number of refugees and persons seeking asylum in Europe in each country, medical screening programs are organised for arriving refugees and asylum seekers. In Switzerland, they are screened for tuberculosis and hepatitis B. They are offered standard vaccinations and immunized for hepatitis B according to screening results. The prevalence of tuberculosis in asylum seekers is 414 per 100,000, 227 per 100,000 of bacteriologically active tuberculosis. Anti-HBc antibody is present in 22% of women and 39% of men. The frequency increases with age and varies greatly according to origin. Initially, refugees were screened for intestinal parasites. Over a quarter were carriers, a large majority asymptomatic. Increasing numbers of asylum seekers come from countries affected by war and insecurity. Systematic screening carried out in Geneva for previous exposure to violence revealed that 61% reported major trauma, 18% reported torture and 37% complained of symptoms such as nightmares, insomnia, flashbacks, etc. The authors discuss issues related to medical screening programs, and their relative usefulness in an increasingly mobile world where the distinction between travellers and migrants is not always clear.

[Bronchospasm, apnea and heart arrest following dipyridamole perfusion scintigraphy]. / Bronchospasme, apnoe en hartstilstand na een dipyridamol-perfusiescintigrafie.

The occurrence of fatal respiratory insufficiency following dipyridamole-thallium imaging is described. The patient, a 67-year-old man, had a history of chronic obstructive lung disease. Since patients with a history of chronic obstructive lung disease have an increased risk of developing bronchospasm after dipyridamole infusion, it is advised to be cautious in performing dipyridamole-thallium imaging in these patients. Dobutamine may be an acceptable alternative to dipyridamole in these patients.

Cholesterol embolism as a complication of left heart catheterisation. Report of seven cases.

Cholesterol embolism after left heart catheterisation by the femoral approach was diagnosed in seven men (mean age 59.6 years) out of a total of 4587 catheterisations. Diabetes was present in four patients, systemic hypertension in three, and signs of extensive atherosclerosis in six; five patients were taking anticoagulant drugs. Acute pain in the legs or abdomen occurred in six patients, two of whom had abdominal angina; renal failure was present in six patients, cutaneous manifestations in five, and a cholesterol embolus was seen in the retina in one. Six out of six patients had an appreciable increase in the erythrocyte sedimentation rate and five out of five had eosinophilia within a week of catheterisation. Renal failure was progressive in five patients, one of whom required haemodialysis. Three patients required amputation of the toes because of gangrene. Four patients died within four and a half months of catheterisation from causes not directly related to cholesterol embolism. At necropsy cholesterol emboli were found in all four patients. Cholesterol embolism is a rare but serious complication of left heart catheterisation.