Human leptospirosis in Denmark 1970-1996: an epidemiological and clinical study.

Epidemiological and clinical aspects of 118 laboratory confirmed cases of human leptospirosis in Denmark from 1970 to 1996 were reviewed. Icterohaemorrhagiae (72%) and sejroe (20%) were the most frequent serovars. The incidence of leptospirosis was 0.09/100,000 inhabitants/y. 93% of the patients were 18-64 y old, 90% were men and 72% of the cases occurred from July to November. Occupational exposure was present in 63% (74/118) of the cases (41% fish farmers, 28%, farmers). Eight percent of the patients had travelled abroad, 7% had been exposed to sewers and 4%, had been exposed through recreational activities (fishing). Initial symptoms were generally non-specific. Weil's disease developed in 63%, of the patients, more often in patients infected with the serovar icterohaemorrhagiae (73%) compared to patients infected with serovars sejroe or saxkoebing (25%). The fatality rate was 7%, all due to icterohaemorrhagiae. Though a rare disease in Denmark, leptospirosis should be considered in certain risk groups as a possible diagnosis in patients with acute febrile illness.

The impact of endurance training on arterial plasma K+ levels and swimming performance of rainbow trout

Arterial plasma K+ and lactate concentrations ([K+]a and [lactate]a), as well as blood oxygenation status, were measured in relation to increasing swimming speeds in rainbow trout Oncorhynchus mykiss. Neither [K+]a nor [lactate]a changed at swimming speeds below 1.5 BL s-1, where BL is total body length. Between 1.5 and 2.0 BL s-1, [K+]a started to increase, and above 2.0 BL s-1 both [K+]a and [lactate]a increased with swimming speed. Training shifted the onset of these increases to higher swimming speeds and increased the critical swimming speed (Ucrit) from 2.4 to 3.0 BL s-1. Blood oxygen content showed no changes in control fish, whereas in trained fish it increased by 22 % at the final swimming speed. From the [K+]a data, we suggest that no loss of K+ occurred from the working muscle at low swimming speeds, allowing an unlimited endurance, whereas moderate and higher speeds were probably associated with a loss of K+ from the working muscles, indicating a limited endurance.

Continuous non-invasive monitoring of energy expenditure, oxygen consumption and alveolar ventilation during controlled ventilation: validation in an oxygen consuming lung model.

BACKGROUND: We have developed a combined indirect calorimetric and breath-by-breath capnographic device (GEM) for respiratory monitoring: oxygen consumption (VO2), carbon dioxide excretion (VCO2), respiratory quotient (RQ), energy expenditure (EE), alveolar ventilation (VA) and dead space/total ventilation (VD/VT). METHODS: The device was tested in a lung model in which VO2 was achieved by combustion of hydrogen. VCO2 was achieved by delivering CO2 into the single alveolus combustion chamber. VO2, VCO2, compliance, and anatomical dead space could be varied independently. RESULTS: Measured VO2 was 101 +/- 3% (SD) of set value at a F1O2 < 0.6 and 101 +/- 7% at a F1O2 > 0.6 during 15 hours of testing. The corresponding VCO2 values were 99 +/- 2% and 102 +/- 7%. The GEM could with good accuracy measure accumulated energy expenditure (EE) during simulated unstable patient conditions up to a F1O2 of 0.8. At F1O2 above 0.8 VCO2 and VO2 could be estimated using a default RQ value of 0.85. On-line estimated VA and VD/VT values could be obtained at any F1O2 up to 1.0. In a test sequence with stable VO2 and VCO2 the GEM adequately followed changes in VA, induced by changes in anatomical dead space, breathing frequency and compliance. CONCLUSION: The overall performance of the device is satisfactory and well comparable with any equipment tested. It allows near-continuous non-invasive monitoring of EE, VO2, VCO2, VA, VD/VT in ventilated, critically ill patients, providing a rationale for ventilator settings and nutritional support.

Effects of isotonic swelling on the intracellular Bohr factor and the oxygen affinity of trout and carp blood.

Blood samples from carp and trout were exposed to overnight tonometry in the presence of noradrenaline to obtain isosmotic cell swelling. The intracellular fixed acid Bohr factor (Φfa(i)) were then measured and compared to the values for unswollen cells (Holk and Lykkeboe 1995). An increase in oxygen affinity appeared for both carp and trout. Part of this increase could be explained by a lower content of organic phosphates, whereas the rest of the increase was ascribed to changes in the association constants of at least one of the phosphate-hemoglobin or oxygen-hemoglobin complexes. However, in spite of a marked swelling and a slightly lower content of organic phosphates, no change in the Φfa(i) appeared.

Catecholamine-induced changes in oxygen affinity of carp and trout blood.

Carp and trout blood maintained at low constant oxygen and carbon dioxide tensions was beta-stimulated. This activated the Na+/H(+)-exchanger of the red cell membrane, leading to increases in red cell pH (pHi) and cell water content, the latter resulting in dilution of hemoglobin and organic phosphates. The increase in pHi was rapid and maintained throughout the experimental period, the trout red cells showing the largest increase. Likewise swelling of the red cells was larger in trout than in carp blood. As a consequence of beta-stimulation the oxygen affinity of the blood increased. In trout the intracellular Bohr factor of unstimulated blood combined with the pHi increase upon stimulation could account for 85% of the increase in oxygen affinity, whereas it only covered 65% of the increase in carp blood. We therefore conclude that blood oxygen affinity is dependent on the red cell hemoglobin concentration in both species, the effect being more marked in carp.