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Notes: A 103-kDa protein present in membrane cytoskeletal preparations from bovine brain has been identified. We have purified this protein to 〉95% homogeneity using gel filtration and ion-exchange chromatography. This protein, p 103, is an asymmetric dimer in dilute solution and has two major variants that can be distinguished by isoelectric focussing, pI 5.60 and 5.75. Using subcellular fractionation, it is most enriched in postsynaptic densities. Immunolocalization with anti-p 103-specific antibodies reveals that it is confined to the dendrites and perikarya; it is apparently absent from spinal cord axons. It coextracts from brain membrane-skeletal preparations with brain spectrin and actin, but in vitro, it does not interact with them.

Notes: Abstract: The molecular forms of angiotensin converting enzyme (ACE; EC 3.4.15.1) in preparations of pig brain cortical microvessels and striatal synaptosomal membranes have been identified by immunoelectrophoretic blot analysis. The cortical microvessels contained only the endothelial form of the enzyme, Mr 180,000, which comigrated with pig kidney ACE on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In contrast, the synaptosomal membranes contained only a smaller form of ACE, Mr 170,000, which represents the neuronal form of the enzyme. No significant differences in inhibitor sensitivity or substrate specificity were detected between the two forms of ACE. In particular, neurokinin A was resistant to hydrolysis by either microvessel or synaptosomal membrane ACE, and the pattern of hydrolysis of substance P by the two preparations was identical.

Notes: Objectives— (1) To define the baseline respiratory function in untreated severe gestational proteinuric hypertension (GPH) and (2) to assess the effects of volume expansion with dextran (MW = 70 000 Dalton) and subsequent vasodilatation with the calcium antagonist verapamil on the baseline respiratory function in severe GPH.Design— Prospective descriptive study.Setting— Reproductive Research Unit, Groote Schuur Hospital, Cape Town, South Africa.Subjects— Six women with severe GPH undergoing stabilization and delivery.Interventions— Baseline haemodynamic and respiratory function was assessed using invasive monitoring. Patients then underwent volume expansion to a pulmonary capillary wedge pressure of 16 mmHg with dextran-70, followed by vasodilatation with the calcium antagonist verapamil. Haemodynamic and respiratory variables were measured, before and after both the fluid load and the reduction (20%) in the mean arterial pressure.Main outcome measures— Mean arterial pressure, heart rate, mean pulmonary arterial pressure, pulmonary capillary wedge pressure, central venous pressure, cardiac index, systemic vascular resistance, pulmonary vascular resistance, respiratory rate, blood gases, alveolar arterial oxygen difference, oxygen availability, oxygen consumption, pulmonary shunt fraction.Results— Baseline oxygen availability/delivery and oxygen consumption indices were consistent with severe tissue ischaemia. Volume loading with 400 ± 114 ml dextran-70 normalized these variables, and subsequent vasodilatation with verapamil did not reduce these indices below the normal limits for pregnancy.Conclusions— These data support the theory that some of the complications of severe GPH may follow organ damage due to prolonged tissue ischaemia. They also support the appropriateness of controlled volume expansion in the management of this condition. We suggest, from these data, that the combination of volume expansion and verapamil vasodilatation lowers the blood pressure without compromising the maternal respiratory function.

Notes: We extend the technique of velocity selection by narrow linewidth laser excitation by measuring the polarization of emission following energy transfer as a function of selected velocity. We apply this to rotationally inelastic collisions in A1ΣuLi2–Xe and find that for most transitions, there is a noticeable decrease in the circular polarization ratio at the center of the Doppler profile. We speculate as to whether the reason for this is dynamical, geometrical, or a combination of the two. We are able to deconvolute cross sections for the transfer of orientation as a function of relative speed which can then be compared with cross sections for the transfer of population.

Notes: We introduce a novel spectroscopic technique which utilizes a two-pulse sequence of femtosecond duration phase-locked optical laser pulses to resonantly excite vibronic transitions of a molecule. In contrast with other ultrafast pump–probe methods, in this experiment a definite optical phase angle between the pulses is maintained while varying the interpulse delay with interferometric precision. For the cases of in-phase, in-quadrature, and out-of-phase pulse pairs, respectively, the optical delay is controlled to positions that are integer, integer plus one quarter, and integer plus one half multiples of the wavelength of a selected Fourier component. In analogy with a double slit optical interference experiment, the two the two pulse experiments reported herein involve the preparation and quantum interference of two nuclear wave packet amplitudes state of a molecule.These experiments are designed to be sensitive to the total phase evolution of the wave packet prepared by the initial pulse. The direct determination of wave packet phase evolution is possible because phase locking effectively transforms the interferogram to a frame which is referenced to the optical carrier frequency, thereby eliminating the high (optical) frequency modulations. This has the effect of isolating the rovibrational molecular dynamics. The phase locking scheme is demonstrated for molecular iodine. The excited state population following the passage of both pulses is detected as the resultant two-beam dependent fluorescence emission from the B state. The observed signals have periodically recurring features that result from the vibrational dynamics of the molecule on the electronically excited potential energy surface. In addition, coherent interference effects cause the magnitude and sign of the periodic features to be strongly modulated. The two-pulse phase-locked interferograms are interpreted herein by use of a simple analytic model, by first order perturbation theory and by quantum mechanical wave packet calculations. We find the form of the interferogram to be determined by the ground state level from which the amplitude originates, the deviation from impulsive preparation of the wave packet due to nonzero pulse duration, the frequency and anharmonicity of the target vibrational levels in the B state, and the detuning of the phase-locked frequency from resonance. The dependence of the interferogram on the phase-locked frequency and phase angle is investigated in detail.

Notes: The pressure-induced broadening and shift of CO spectral lines has been measured at room and liquid-nitrogen temperatures, using He and H2 as perturber gases. The R(2), P(8), and R(14) rovibrational transitions for the fundamental vibrational band were studied, which absorb in the 5 μm region of the infrared. A novel heterodyne spectrometer operating near 5 μm wavelengths has been used for these measurements. The local oscillator (LO) for the spectrometer was a frequency-doubled CO2 laser, with CdGeAs2 as the nonlinear crystal. This LO was step tunable and could be frequency stabilized to better than 0.5 MHz absolute accuracy. A spectral resolution of 20 MHz was achieved. The CO–He line-broadening measurements were accurate enough (∼2%–3% absolute accuracy) to distinguish between two proposed intermolecular potential models for this system. Also, a measured increase in the broadening coefficient as a function of rotational quantum number j was observed for CO–He at temperatures of 80 K. This is not easy to explain in the context of so-called "sudden approximations'' which have been used to interpret pressure-broadening data for this system. The shift measurements are the first reported for the fundamental vibrational band of CO with He or H2. For H2, there appears to be a decrease of the shift with the rotational state j of the transition. For both He and H2, there is a pronounced temperature dependence of the shift for the P(8) transition, the shift becoming "redder'' (toward lower frequency) as the temperature decreases from 298 to 80 K.

Notes: We present a model that accounts for the observation described in the first paper of this series (I) of a dip in the polarization ratio profile observed in certain rotationally inelastic processes as a narrow line laser is tuned across the Doppler profile. The model is based on conservation of the projection of j along the kinematic apse [Khare, Kouri, and Hoffmann, J. Chem. Phys. 74, 2275 (1981)], a consequence of rotational angular momentum transfer in the impulsive limit. As an illustration, we present calculations of lab frame observations expected for several examples of scattering behavior in the collision frame and conclude that information on the state-to-state differential scattering cross section is contained in the polarization profile. We display a number of figures that make explicit the relationship between the relative momentum and rotational angular momentum vectors in the experiment and illustrate the "stereochemical dynamics'' responsible for the polarization dip.