Exercise tolerance at 4 and 6 ATA

Seven normal male subjects performed 5-min bicycle exercise ranging from 50-100% maximum oxygen uptake at 4 ATA and three were also studied at 6 ATA. At all pressures, the subjects breathed 0.2 ATA O2 plus nitrogen. All subjects were able to perform maximum work at all pressures. No pressure-dependent variations in heart rate, O2 uptake, or CO2 output were noted. At both 4 and 6 ATA, ventilation was decreased at exercise levels greater than 80% maximum O2 uptake. The magnitude of the decrease was not great, however, and signified only minor CO2 retention. In some instances exercise ventilation closely approached the 15-S maximum breathing capacity and these subjects noted severe dyspnea, possibly due to dynamic compression of large airways. In three subjects, respiratory frequency was measured as well as minute ventilation; this relationship did not change with depth. Subjects performing heavy exercise at 6 ATA noted disturbances of consciousness, presumably due to N2 narcosis.     

Effect of length of gestation on maternal cellular immunity to human trophoblast antigens

Maternal lymphocyte reactivity to human trophoblast antigens was studied in placentas of gestational ages 8 to 14 weeks and 32 to 34 weeks, respectively. Significant trophoblast lysis became apparent after 24 hours' incubation in the latter case compared with a time lag of 72 hours in the terminated gestations. Maternal cellular immunity, therefore, was not detected during the first 3 1/2 months of pregnancy, but was detectable by the time of parturition. The possible significance is discussed with respect to the antigenic stimulus and survival of the fetal allograft.     

On the criteria for instrumental autonomic conditioning: A reply to Katkin and Murray.

In their recent review of instrumental conditioning of autonomic functions, E. S. Katkin and E. N. Murray (see 42: criticized most of the existing studies on the human level as artifactual on 1 or more grounds. The criteria they employed for rejecting these demonstrations are themselves open to criticism, however. Specifically, it is argued that (1) peripheral or cognitive mediation hypotheses are unlikely alternative explanations of the obtained results; (2) an increase in response frequency over a preconditioning operant level is not a necessary condition for demonstrating an increase in response probability with contingent reinforcement; and (3) yoked-control designs, frequently used in this research, do not automatically invalidate experiments in which they are employed. It is concluded that the strongest hypothesis to account for the existing data remains the direct instrumental strengthening of autonomic activity. (35 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Elbe flood in August 2002--occurrence of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/F) and dioxin-like PCB in suspended particulate matter (SPM), sediment and fish.

As a result of extreme precipitation in August 2002 major flooding occurred in the catchment area of the rivers Elbe, Vltava (Moldau) and Mulde. Pollutants from industrial sites and from municipal sewage treatment works (STW) entered the Elbe and led to a serious pollution problem in the river. PCDD/F concentrations (in pg WHO-TEQ/g dw) in SPM ranged from 7-150, in sediments from 3-140; the "safe sediment value" of 20 was exceeded in 46% of the samples. 24 eels showed a wide concentration variation for these contaminants. The WHO-PCDD/F+PCB-TEQ values lay in the range from 11-56 pg/g ww, whereby the WHO-PCB-TEQ values were several times higher than the WHO-PCDD/F-TEQ values. The maximum permitted value of 4 pg WHO-PCDD/F/g ww (EU Directive No. 2375/2001) was reached or exceeded in 54% of the individuals. A statistical analysis using data from SPM and sediment samples showed that in the Czech river section the flooding activated a contamination source in the vicinity of the Spolana works. The influence of the tributary Mulde could be clearly demonstrated. Only a major clean-up of the contaminated sites in Bitterfeld can lead to a mid to long term improvement in respect of PCDD/F and dioxin-like PCB input into the Elbe.