A computer program, GelExplorer, which uses a new methodology for obtaining quantitative information about electrophoresis has been developed. It provides a straightforward, easy-to-use graphical interface, and includes a number of features which offer significant advantages over existing methods for quantitative gel analysis. The method uses curve fitting with a nonlinear least-squares optimization to deconvolute overlapping bands. Unlike most curve fitting approaches, the data is treated in two dimensions, fitting all the data across the entire width of the lane. This allows for accurate determination of the intensities of individual, overlapping bands, and in particular allows imperfectly shaped bands to be accurately modeled. Experiments described in this paper demonstrate empirically that the Lorentzian lineshape reproduces the contours of an individual gel band and provides a better model than the Gaussian function for curve fitting of electrophoresis bands. Results from several fitting applications are presented and a discussion of the sources and magnitudes of uncertainties in the results is included. Finally, the method is applied to the quantitative analysis of a hydroxyl radical footprint titration experiment to obtain the free energy of binding of the lambda repressor protein to the OR1 operator DNA sequence.

Rapid injection of 40 ml. of 5 per cent saline into the femoral or brachial arteries of 24 dogs resulted in an average elevation of arterial blood pressure of +42/+20 mm. Hg, an increase in the heart rate of +20 beats/min., and an acceleration of the respiratory rate of +140 per cent. The response began 6 to 10 seconds after the onset of injection and lasted for 5 to 30 minutes. It occurred with the injection of hypertonic solution of saline, dextrose, and urea. The magnitude of the response was related to the degree of hypertonicity. Responses could be provoked by 10 ml. of 1.25 per cent saline. Rapid intra-arterial injection of isotonic saline, dextrose, and urea solutions, and of whole blood in volumes up to 80 ml. had no circulatory effect. Rapid injection of distilled water, 0.225 per cent and 0.45 per cent saline into the femoral or brachial arteries resulted in a slight degree of hypotension and a rise in the respiratory rate. The appearance of circulating catechol amines following the response to intra-arterial injection of hypertonic solutions was suggested by the demonstration of hypotensive response to intravenous injection of phentolamine. These responses to injection of hypertonic and hypotonic solutions in the femoral artery were abolished by section of the sciatic nerve in animals with an ipsilateral partially-transected hind limb, a preparation which left intact only the femoral artery, femoral vein, and femur. Sciatic section in the intact limb reduced but did not abolish the response. Removal of the sympathetic chain from the eleventh thoracic through the third lumbar ganglia had no apparent effect. It is concluded that the response to femoral aud brachial intra-arterial injection of hypertonic and hypotonic solutions is initiated by peripherally located "osmoreceptors" in the distribution of these arteries and is mediated via a reflex whose afferent fibers travel in the peripheral somatic nerves and enter the spinal cord without passing through the sympathetic chain. The efferent are is the sympathetic nervous system.

MethodsPreliminary studies were performed on 18 dogs to clarify the details of surgical technic and to study acute changes in aortic, left atrial, and left ventricular end diastolic pressures. These studies indicated that the diameter of the largest shunt which could be tolerated chronically was 5 mm at the narrowest point; the smallest which would produce progressive hemodynamic changes in the surviving animal was 2.5 mm.Female mongrel dogs weighing 16 to 22 kg were anesthetized intravenously with pentobarbital (30 mg/kg). The heart and the left subclavian artery were exposed and an anastomosis between the left atrium and the proximal end of the divided left subclavian artery was made with a crimped, woven, Teflon graft, 6 mm in diameter. The atrial end of the graft was implanted either into the free atrial wall or into the stump of the amputated atrial appendage. The latter technique was found to be most satisfactory-During surgery, pressures were monitored by 1 Electrocardiographic changes indicating development of left ventricular h\ipertrophu following creation of a left subclavian artery-left atrial shunt. Note slight widening of the QSR complex, increase in amplitude of the R wave and dearth of the Q wave in I, II, aVF, and the left precordial leads, increase in intrinsicoid deflection in V o and increase of the depth of the inverted T waves in these leads.

No abstract