Albumin uptake by renal lymphatics with and without obstruction of the renal vein.

Experiments involving injection of radio-iodinated albumin into the left renal arteries or left ureters of dogs indicate that the renal lymphatics are capable of a major contribution in returning to the circulation albumin (or other large molecules) escaping from renal capillaries. I131-albumin was injected into the jugular vein of controls or into the left renal artery or in retrograde manner into the left ureter of female dogs. Experimental groups included those with no obstruction, occlusion of left renal veins or left renal lymphatics, or both. Collections were made from the right femoral artery, both renal veins, thoracic duct and both ureters at frequent intervals for 2 to 4 hours. Data analysis included I131 concentration, specific activity, rate of recovery and selected ratios. After renal arterial injection, the percentage of I131 recovered in thoracic duct lymph of dogs without renal venous obstruction was 5 to 10 times that recovered in those that received injections into the jugular vein. In dogs with renal venous obstruction, recovery from the thoracic duct was 10 to 1,000 times that in control dogs. Most of the differences occurred during the first hour, after which time as recirculation and redistribution occurred the rates of appearance in thoracic duct lymph in each group were similar. The differences in the ratios of concentration in thoracic duct lymph to concentration in femoral arterial blood were also much greater when the renal vein was obstructed than in dogs with no obstruction. The greater return of albumin through the thoracic duct in those with impeded renal venous outflow was probably related to both sequestered concentration and increased intrarenal pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Essential hypertension predicted by tracking of elevated blood pressure from childhood to adulthood: the Bogalusa Heart Study.

It is well known that blood pressure (BP) levels persist over time. The present investigation examines tracking of elevated BP from childhood to adulthood and its progression to essential hypertension. In a community study of early natural history of arteriosclerosis and essential hypertension, a longitudinal cohort was constructed from two cross-sectional surveys > 15 years apart: 1505 individuals (56% female subjects, 35% black), aged 5 to 14 years at initial study. Persistence of BP was shown by significant correlations between childhood and adulthood levels (r = 0.36 to 0.50 for systolic BP and r = 0.20 to 0.42 for diastolic BP), varying by race, sex, and age. These correlations remained the same after controlling for body mass index (BMI). Twice the expected number of subjects (40% for systolic BP and 37% for diastolic BP), whose levels were in the highest quintile at childhood, remained there 15 years later. Furthermore, of the childhood characteristics, baseline BP level was most predictive of the follow-up level, followed by change in BMI. Subsequently, even at ages 20 to 31 years, prevalence of clinically diagnosed hypertension was much higher in subjects whose childhood BP was in the top quintile: 3.6 times (18% v 5%) as high in systolic BP and 2.6 times (15% v 5.8%) as high in diastolic BP, compared to subjects in every other quintile. Of the 116 subjects who developed hypertension, 48% and 41% had elevated childhood systolic and diastolic BP, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of obstructed renal lymph flow on effects of a nephrotoxin on renal function.

To study the influence of disrupted renal lymph drainage on the effects of a nephrotoxin, uranyl acetate (0.028 to 0.05 mg/kg body weight) was injected into dogs the same day that the renal lymphatics were ligated and transected bilaterally. Larger doses produced effects which masked the influence of lymphatic ligation; a control group receiving uranyl acetate underwent a sham ligation of renal lymphatics. In renal function studies at 1, 3, 8 and 12 weeks after surgery and uranyl acetate, the urea, creatinine, PAH and electrolyte clearances of the "ligated" dogs were lower than those of the "non-ligated" shams. Daily clearances of urea and creatinine of the ligated were also lower than those of the shams. Urinary volume and protein excretion were also greater in the ligated subjects although elevated in both groups. The significance of the differences in the daily electrolyte clearances was less convincing. Renal lymphatic ligation with uranyl acetate injection produced greater changes than either lymphatic ligation or uranyl acetate alone. That the changes were not permanent or did not lead to chronic renal disease was probably due to regeneration of lymphatics, development of alternate routes of lymph flow and/or the small dose of uranyl acetate used to demonstrate the influence of lymphatic dysfunction on response to the nephrotoxin.