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Neoadjuvant SABR for Renal Cell Carcinoma Inferior Vena Cava Tumor Thrombus—Safety Lead-in Results of a Phase 2 Trial
To evaluate the feasibility, safety, oncologic outcomes, and immune effect of neoadjuvant stereotactic radiation (Neo-SAbR) followed by radical nephrectomy and thrombectomy (RN-IVCT).
Targeting succinate dehydrogenase with malonate ester prodrugs decreases renal ischemia reperfusion injury
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<renal and vascular changes produced by weightlessness for the purpose of defining and verifying an experiment suitable for use in a biosatellite< progress report
Blood flow measured by electromagnetic flow meter to determine cardiac output
Renal clearance studies of effect of left atrial distension in the dog.
Investigation of the water diuresis of left atrial distension in 16 dogs on the basis of clearance studies employing hydration, chronic and acute salt loading, deoxycorticosterone (DOCA) in excess, and distal tubular nephron blockade with diuretics. The diuresis was found in hydrated and salt-loaded dogs and was independent of DOCA and presumed renin depletion. It was not found in five dogs after distal tubular blockade. No significant reproducible saluresis was ever documented. The water diuresis was always stopped by exogenous vasopressin (seven dogs). Antidiuretic hormone inhibition with distal tubular nephron water permeability changes appears to be the sole mechanism of the diuresis of left atrial distension in the dog.
Incidence of Lucke renal adenocarcinoma in Rana pipiens as determined by histological examination.
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Renal function in the hibernating, and hypothermic hamster Mesocricetus auratus
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Hemodynamics, renal function, plasma renin, and aldosterone in man after 5 to 14 days of bedrest
Continuous bedrest for 5 to 14 days had no significant effect on resting heart rate, blood pressure, or cardiac output in six normal men. Head-up tilt induced greater tachycardia in 5 of 6 patients after bed rest than in the control period. Propranolol diminished both tachycardia and the incidence of hypotension and faintness in upright posture. Plasma volume fell, extracellular fluid volume increased, and plasma renin activity was significantly elevated following bedrest. Unusually large increases in plasma renin followed head-up tilt or administration of isoproterenol during bedrest and after resuming normal activity. During bedrest, plasma aldosterone was often increased in the early morning. It is concluded that after bedrest, upright posture evokes strong beta-adrenergic activity as well as exaggerated metabolic and circulatory responses which can be reduced or abolished by the beta-adrenergic blocker, propranolol.
Ultrasonic Doppler measurement of renal artery blood flow
Studies were made of (1) blood flow redistribution during lower body negative pressure (LBNP), (2) the profile of blood flow across the mitral annulus of the heart (both perpendicular and parallel to the commissures), (3) testing and evaluation of a number of pulsed Doppler systems, (4) acute calibration of perivascular Doppler transducers, (5) redesign of the mitral flow transducers to improve reliability and ease of construction, and (6) a frequency offset generator designed for use in distinguishing forward and reverse components of blood flow by producing frequencies above and below the offset frequency. Finally methodology was developed and initial results were obtained from a computer analysis of time-varying Doppler spectra.
Cardiovascular and renal effects of head-out water immersion in man - Application of the model in the assessment of volume homeostasis
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Renal sodium reabsorption following induction of and recovery from volume expansion
In the rat, infusion of a volume of isotonic saline equal to 2% of body weight resulted in an 82% increase in the delivery of filtrate out of the proximal tubule but little or, in some animals, no change in the urinary excretion of sodium. By contrast, further degrees of volume expansion resulted in lesser increases in the distal delivery of filtrate, but were associated with a marked increase in the urinary excretion of sodium. Sixty minutes following completion of volume expansion, while the animals were still in positive sodium balance, the urinary excretion of sodium decreased 52% compared to a decrease of only 24% in the distal delivery of filtrate. During the course of progressive volume expansion and during the recovery phase, there was a dissociation between alterations in sodium reabsorption in the proximal convoluted tubule and in the whole kidney. These studies indicate that although the proximal tubule is more sensitive to changes in the extracellular fluid volume, distal nephron sites are ultimately responsible both for the natriuresis of volume expansion and the relative antinatriuresis of the recovery periods.
Assessing applicants to the NASA flight program for their renal stone-forming potential
Because spaceflight can provoke the formation of kidney stones, 24-hour urine samples for 104 male applicants were analyzed for stone-forming risk factors prior to their selection into the NASA astronaut-mission specialist corps. A high level of supersaturation (with either calcium oxalate, brushite, or monosodium urate) was noted in these applicants which predisposes them to the crystallization of stone-forming calcium salts. It is suggested that most of the abnormal stone risk factors found were environmental, rather than metabolic, in origin.
Renal response to seven days of lower body positive pressure in the squirrel monkey
As a ground-based model for weightlessness, the response of the chair-trained squirrel monkey to lower body positive pressure (LBPP) was evaluated in a length of study similar to a typical Space Shuttle mission (7 days). Results were compared to time control experiments that included chair-sitting without exposure to LBPP. Chronic exposure to LBPP results in an acute diuretic and natriuretic response independent of changes in plasma aldosterone concentrations and produces a chronic reduction in fluid volume lasting the duration in the stimulus.
Changes in renal function and fluid and electrolyte regulation in space flight
The cephalad fluid redistribution resulting from weightlessness has a number of physiologic consequences. Plasma volume is reduced soon after weightlessness is reached, and red blood cell mass reduction follows. Plasma atrial natriuretic peptide, which inhibits aldosterone secretion, was elevated during space flight while plasma aldosterone was below preflight levels. Serum sodium was also reduced and potassium was elevated. Antidiuretic hormone (ADH) was markedly elevated at almost all measurement times in the first eight days of flight, but plasma volume did not return to preflight levels.
The preservation of urine samples for determination of renal stone risk factors
A preservation technique for urine specimens before determination of stone risk factors was evaluated. The purpose of these experiments was to prove the effectiveness of the preservatives used to prevent changes in the concentrations of those constituents measured. Measured concentrations in fresh specimens were compared with those in the same specimens after storage with the preservatives. Refrigeration at 4 degrees C up to five days was appropriate in a laboratory setting, as no significant changes in urinary concentrations occurred. Refrigeration, however, did not offer a convenient method for shipping. Chemical preservation was found to be an effective alternative to refrigeration. Thymol prevented changes in concentration of pH, citrate, uric acid, sulfate, sodium, potassium, and cyclic AMP, while a mixture of hydrochloric (HCl) acid and boric acid prevented changes in calcium, magnesium, phosphorus, oxalate, ammonium, and creatinine. Thus, the addition of thymol or HCl/boric acid to urine specimens will prevent significant changes in the concentrations of stone risk factors.
Citrate and renal calculi: an update
Citrate is an inhibitor of the crystallization of stone-forming calcium salts. Hypocitraturia, frequently encountered in patients with nephrolithiasis, is therefore an important risk factor for stone formation. Potassium citrate provides physiological and physicochemical correction and inhibits new stone formation, not only in hypocitraturic calcium nephrolithiasis but also in uric acid nephrolithiasis. Inhibition of stone recurrence has now been validated by a randomized trial. Ongoing research has disclosed additional causes of hypocitraturia (sodium excess, low intestinal alkali absorption, but not primary citrate malabsorption). Moreover, new insights on potassium citrate action have been shown, notably that some of absorbed citrate escapes oxidation and contributes to the citraturic response, that ingestion with a meal does not sacrifice physiological or physicochemical action, that orange juice mimics but does not completely duplicate its actions, that potassium citrate may have a beneficial bone-sparing effect, that it may reduce stone fragments following ESWL, and that danger of aluminum toxicity is not great in subjects with functioning kidneys. Finally, the research on potassium citrate has led to two promising products, calcium citrate as an optimum calcium supplement and potassium-magnesium citrate which may be superior to potassium citrate in the management of stone disease.