Serial physiologic studies of a chronic obstructive pulmonary disease patient in acute respiratory failure: clues for weaning?

A patient with severe chronic obstructive pulmonary disease was studied during acute respiratory failure. On the day of intubation his respiratory rate was 42, the tidal volume 295 ml, and the maximal inspiratory pressure 8 cm H2O. These parameters improved with rest by mechanical ventilation to 16, 620 ml, and 30 cm H2O, respectively, on the day of successful weaning. Daily tidal volumes correlated significantly with maximal inspiratory muscle pressures (r = 0.936; p less than 0.001). Respiratory system compliances and resistances were measured by the inflation, the end-inspiratory occlusion, and the interrupter methods. In general, inflation compliance and occlusion compliance were comparable and significantly smaller than the interrupter compliance (p less than 0.002 and p less than 0.003, respectively), whereas inflation resistance and occlusion maximal resistance were also comparable but significantly smaller than the interrupter resistance (p less than 0.0008 and p less than 0.0006, respectively). The former was due to increased hysteresis of the pressure volume curves and the latter due to expiratory compression of airways. The compliance was low, and the resistance was high on the day of intubation and became much higher and lower, respectively, on the day of successful extubation. These physiological changes were associated with weaning difficulty. We conclude that respiratory failure and weaning are complex physiologic events under the influence of muscle strength, lung mechanics, gas exchange, and control of breathing. Therefore, prediction of weaning success based upon one or two measured parameters as has been done is probably inadequate in difficult patients.     

Effects of in vivo and in vitro exposure to rhodamine dyes on mitochondrial function of mouse embryos

Cationic rhodamines (Rh 123 and Rh 6G) can cause developmental toxicity in mice and inhibit embryonic mitochondrial respiration following in vivo or in vitro dye exposure. Rh B, a neutral rhodamine, fails to show such effects at comparable doses. To assess effects of rhodamines on development, F0F1ATPase activity and ADP translocation were measured on gestation day (GD) 12 in embryonic and adult mitochondria. ATP synthesis in embryonic mitochondria transplacentally exposed to Rh 123 (15 mg/kg/day) or Rh 6G (0.5 mg/kg/day) given to dams by i.p. injection from GD 7 to 10 were inhibited 39% and 49%, respectively. When isolated mitochondria were treated, dose-dependent inhibition was seen; at 5 micrograms of dye/mg mitochondrial protein, ATP synthesis was inhibited 65% and 81% by Rh 123 and Rh 6G, respectively. When F0F1ATPase activity was assessed, in vitro Rh 123 and Rh 6G exposures at levels up to 8 micrograms/mg mitochondrial protein resulted in enzyme inhibition, but at 10 micrograms/mg, ATPase activity was stimulated. Uncoupler-stimulated ATPase activity was also inhibited. ADP translocation was decreased by 19.1% and 37.7% by Rh 123 and Rh 6G, respectively, at dye concentrations of 20 micrograms/mg. Results of in vitro exposure of maternal liver mitochondria were similar to those for embryonic mitochondria, whereas liver from dams exposed in vivo on GD 7-10 was unaffected on GD 12. In vivo or in vitro treatment with Rh B did not affect any embryonic or maternal parameters. Such results support the hypothesis that inhibition of mitochondrial energy metabolism is a mechanism for the developmental toxicity of cationic rhodamines.     

Bizarre delusions and first-rank symptoms in a first-admission sample: A preliminary analysis of prevalence and correlates

This report examines the prevalence and correlates of bizarre delusions and Schneider's first-rank symptoms (FRS) in a first-admission sample with psychosis. A total of 196 patients were assessed with the Structured Clinical Interview for DSM-III-R (SCID) and given a consensus diagnosis. Project psychiatrists blind to the consensus diagnoses coded each delusion and hallucination in the sample for both FRS and DSM-III-R bizarreness. Interrater reliability of bizarreness was lower than that of FRS (κ = .681 v 861). The majority of symptoms (72%) were neither bizarre nor FRS, and of the remainder, bizarre delusions that were not also FRS were extremely uncommon. The prevalence of FRS was 70% in schizophrenia, 29% in psychotic bipolar disorder, and 18% in psychotic depression. For seven schizophrenic patients (7.45%), diagnosis of that disorder depended on the presence of a DSM-III-R bizarre delusion to meet criteria. There was a trend for FRS to be associated with poorer prognostic features in the schizophrenic sample. We concluded that although the constructs of bizarre delusions and FRS overlap, FRS were a more important feature in schizophrenia than bizarreness. The rarity of bizarre delusions that were not FRS, combined with the lower reliability of their assessment as compared with that of FRS, raises questions about the continued emphasis on this phenomenon in the definition of schizophrenia.