Oxygen transport during extracorporeal oxygenation for the treatment of adult respiratory distress syndrome

An inventory of hemodynamic and respiratory measurements was obtained in two patients with acute respiratory failure syndrome prior to and during venoarterial extracorporeal membrane oxygenation for study of oxygen transport. As the inspired oxygen concentration fraction was reduced from 1.0 to 0.5 and paO2 was increased from less than 50 to physiologic ranges during extracorporeal membrane oxygenation, tachycardia and pulmonary hypertension were reversed. Total oxygen transport was reduced rather than increased. Oxygen consumption and oxygen extraction were not altered during extracorporeal membrane oxygenation. However, a striking reduction was observed in cardiac output. After reversal of anoxemia, the total of the cardiac output of the patient and the extracorporeal membrane oxygenation flow were less than the cardiac output of the patient prior to extracorporeal membrane oxygenation. These observations provide evidence that the beneficial effects of extracorporeal membrane oxygenation stem, at least in part, from a reduction of the work load on the heart. Since high cardiac output failure is observed during progression of adult respiratory distress syndrome, mechanical support of circulation during extracorporeal membrane oxygenation may be of primary therapeutic benefit.

The plasma membrane of human placenta. Isolation of microvillus membrane and characterization of protein and glycoprotein subunits

A microvillus plasma membrane-enriched fraction of human placenta was obtained by a combination of differential, isopycnic, and rate-zonal centrifugation techniques. Assays for enzyme markers from mitochondria, lysosomes, peroxisomes, endoplasmic reticulum, and plasma membrane indicated a relative enrichment of plasma membrane between 10- and 20-fold over the most prominent contaminating enzyme markers. Electron microscopy verified the microvillus ultrastructure of the isolated placental membrane and the lack of significant contamination by identifiable organelles. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the microvillus membrane fraction revealed a protein and glycoprotein subunit composition. There were 16 major protein subunits and 10 major glycoprotein subunits, and apparent molecular weights are assigned to these subunits. 32P-labeling of the microvillus membrane-associated alkaline phosphatase indicated that this enzyme is one of the major glycoproteins of the human placental microvillus membrane.

Rattlesnake venom shock in the rat: development of a method

A model in Wistar rats (n = 30, 279-345 g) was developed to study circulatory, respiratory, metabolic, and lethal effects of an intravenous infusion (30 min; 1.25, 1.5, 1.75, and 2.0 mg/kg) of rattlesnake (Crotalus viridis helleri) venom. Venom produced perfusion failure with lactacidemia, hemoconcentration, hypoproteinemia, and death. The severity of poisoning was proportional to the quantity of venom given and to the elevation in lactic acid and hematocrit. Hemorrhages in the diaphragm, intercostal muscles, and intestine were observed at necropsy. In a separate test, rats (n = 12, 311-355 g) received an infusion of 1.5 mg/kg of venom or physiological salt solution. Blood volume was measured 30 min after the end of infusion in both groups with radioiodinated (125I) human serum albumin (RIHSA) and 51Cr-labeled rat red cells. Venom produced a significant reduction in total blood volume index (35%, P less than 0.001), plasma volume index (46%, P less than 0.001), and red cell mass indec (22% P less than 0.005). The slope of the RIHSA-disappearance curve of animals that received venom was more than twice that of the control group. We conclude that perfusion failure following rattlesnake envenomation is associated with hypovolemia due to increases in vascular permeabiltiy and hemorrhage.

Pioneer 10 Observations of the Ultraviolet Glow in the Vicinity of Jupiter

A two-channel ultraviolet photometer aboard Pioneer 10 has made several observations of the ultraviolet glow in the wavelength range from 170 to 1400 angstroms in the vicinity of Jupiter. Preliminary results indicate a Jovian hydrogen (1216 angstrom) glow with a brightness of about 1000 rayleighs and a helium (584 angstrom) glow with a brightness of about 10 to 20 rayleighs. In addition, Jupiter appears to have an extensive hydrogen torus surrounding it in the orbital plane of Io. The mean diameter of the torus is about equal to the diameter of the orbit of Io. Several observations of the Galilean satellites have also occurred but only a rather striking Io observation has been analyzed to date. If the observed Io glow is predominantly that of Lyman-alpha, the surface brightness is about 10,000 rayleighs.

An Atmosphere on Ganymede from Its Occultation of SAO 186800 on 7 June 1972

On 7 June 1972 the third , Jovian satellite Ganymede occulted the eighth-magnitude star SAO 186800. Successful photoelectric observations obtained at Lembang, Java (Indonesia), and Kavalur, India, show nonabrupt immersions and emersions, indicating the presence of an atmosphere whose surface pressure is greater than about 10(-3) millibar. By fitting the two occultation durations as chords to a model disk, the diameter is found to be 5270 (+30, - approximately 200) kilometers, the major error contribution arising from the uncertain atmospheric thickness below the occultation layer. The derived mean density is 2.0 (-0.03, + approximately 0.2) grams per cubic centimeter.

A double monochromator for the extreme ultraviolet

The optical design of a double monochromator suitable for use in the extreme uv is presented. The system employs fixed entrance and exit slits and two concave diffraction gratings which are rotated to vary the wavelength at the exit slit. Adjustment of the optical parameters and use of symmetry produces an approximate focusing condition accurate to fourth order in grating rotation. The defocusing at the exit slit is comparable to the Seya mounting. The astigmatism is calculated and the transmission properties briefly discussed.