Arnold S. Relman

The regulation of renal bicarbonate reabsorption by plasma carbon dioxide tension.

Pitts, Lotspeich, Ayer, and Schiess (1, 2) have shown that in acute metabolic acidosis or alkalosis the normal kidney handles bicarbonate as if there were a maximal rate of tubular reabsorption which is a direct linear function of the glomerular filtration rate (approximately 2.5 to 2.8 mEq. HCO5 per 100 cc. GFR, in dog and man). At plasma bicarbonate concentrations significantly below 25 mEq. per L., bicarbonate is completely reabsorbed and the urine is acid. When plasma bicarbonate concentration is elevated above this threshold value all the filtered bicarbonate in excess of the limiting rate is excreted in the urine. In respiratory disturbances of acid-base balance, however, the bicarbonate threshold must be changed considerably, because in respiratory alkalosis the urine is alkaline despite low plasma bicarbonate concentrations (3-5) and in respiratory acidosis it is acid when plasma bicarbonate is high (6). The mechanisms initiating these changes in bicarbonate transport have not yet been elucidated, although from a priori considerations one would suspect that they must operate through a change in either carbon dioxide tension or extracellular fluid pH. The purpose of this report is to present observations demonstrating that respiratory regulation of bicarbonate reabsorption is effected through changes in carbon dioxide tension and is independent of extracellular fluid pH.

Treatment of end-stage renal disease: free but not equal.

The End Stage Renal Disease (ESRD) program was enacted by Congress in 1972 to provide Medicare funding for the treatment of chronic renal failure in all patients who required it and could presumabl...

Education to defend professional values in the new corporate age.

The corporate transformation of medicine raises questions about the basic purposes and values of the profession and the physicians social role that have not been adequately considered in medical school and residency curricula. Medical schools and graduate programs need to make students and trainees more aware of the conflict between traditional professional values and the imperatives of the market, so they will be better prepared to defend these values in the new business climate. Otherwise, medical schools and teaching hospitals could simply become trade schools, turning out sophisticated technicians, future entrepreneurs, and managers. As a starting point for educational reform, the author suggests that students (1) learn the social and political history of the medical profession of the United States over the past 200 years; (2) be introduced to the economic dimensions of health care--where the money comes from and how it is spent; (3) learn the history of health maintenance organizations, and understand the different forms of managed care and how they work; (4) become familiar with the health care reforms proposed by the Clinton Administration in the early 1990s, and understand why they were defeated and what has happened to health care reform since then; (5) examine the conflict between the culture of business managers and that of practicing physicians, and consider the recent efforts to achieve “quality control” as a balance to the emphasis on price; (6) be challenged to think about the important ethical, legal, and professional issues raised by the industrialization of health care; and (7) consider the political and professional options that might preserve the most important principles of medical professionalism while still addressing the social objectives of cost control, community service, and universal access. The author concludes that to prevent medicine from becoming merely a technologic business, the medical profession will have to become more actively involved with other policymakers and representatives of the public in efforts to improve the health care system, while preserving professional and social values. To do this, physicians will need a better knowledge of the health care system and its problems than most of them possess. This is a challenge medical educators must now address.

STUDIES OF THE ANTIDIURESIS OF QUIET STANDING: THE IMPORTANCE OF CHANGES IN PLASMA VOLUME AND GLOMERULAR FILTRATION RATE

It has long been known that when a man stands motionless, urine flow (1-13) and the excretion of chloride (2, 3, 5, 7, 11) and of sodium (5, 13) decrease markedly. Simultaneously, the plasma contracts in volume and increases in concentration (8, 10, 14-17), while the blood flow through the kidneys (9, 10, 18, 19) and other abdominal viscera (20) diminishes, and the rate of glomerular filtration of plasma and its contained sodium is reduced (6, 9, 10, 13, 18, 21). There is some evidence that release of the posterior pituitary antidiuretic hormone may be responsible for the retention of water (11) but the mechanism of the retention of sodium and the stimulus or stimuli initiating it remain obscure. Some renal physiologists would place greatest emphasis on the reduction in glomerular filtration rate which occurs during standing, and the resulting decreased load of sodium presented to the tubules (5, 22, 23). It is not likely that an increase in the renal venous pressure (24, 25) plays an important role in the antidiuresis of quiet standing, because when a subject is tilted from the supine to the erect position, pressure in the inferior vena cava at the level of the kidneys does not rise to the level reported by Blake and associates (25) to cause a reduction in the urine flow, and the renal arterio-venous pressure gradient does not change materially (26).

Economic Incentives in Clinical Investigation

The increasing commercialization of medical care has created conflicts of interest for the many practicing physicians who have financial stakes in the health care facilities to which they refer the...

Renal impairment due to sarcoid infiltration of the kidney; report of a case proved by renal biopsies before and after treatment with cortisone.

IT is well known that sarcoid can involve many organs. At autopsy it is not rare to find infiltration of the kidneys,1 but this is usually quite minimal in degree. Clinical renal insufficiency may ...

Long-term results of steroid therapy in adults with idiopathic nephrotic syndrome

Abstract This study analyzes the results in sixty-eight patients with the idiopathic nephrotic syndrome treated with adrenal corticoids and followed for a period averaging five and a half years. Approximately one fourth of the patients responded to steroid therapy with a complete remission (i.e., protein excretion less than 100 mg. per day) which, in most cases, was sustained after discontinuation of treatment; four patients, however, remained dependent upon steroid therapy. Beneficial steroid responses occurred only among patients treated within six months of onset of the disease. An additional 14 per cent of patients, whose proteinuria did not disappear during treatment, had a spontaneous remission of their disease at intervals ranging from one to five years after treatment had been discontinued. Thus slightly more than one third of the adults with the idiopathic nephrotic syndrome treated with steroids ultimately became free of proteinuria. Of the group who did not have complete remissions, roughly one-third have either died of uremia or now have significantly impaired renal function after an over-all follow-up of approximately five years. Deterioration of renal function developed only among those who continued to excrete more than 2 gm. of protein per day; the incidence of renal insufficiency in this group was more than 50 per cent. No patient whose protein excretion has fallen to less than 2 gm. per day has so fat shown evidence of significant renal deterioration. The incidence of complications due to treatment was 25 per cent in the group as a whole; however, these complications occurred mainly in patients who received a prolonged daily course of steroid therapy. Inasmuch as intermittent therapy is associated with a low incidence of significant side effects and is seemingly just as effective as continuous therapy, we recommend that patients with idiopathic nephrotic syndrome be treated on an intermittent schedule. Definitive evaluation of the effect of steroids on the natural history of the idiopathic nephrotic syndrome awaits a suitably controlled prospective study. We believe, however, that when the present findings are examined in the light of what is known about the untreated course of the disease, they strongly suggest that steroids have significant beneficial effects. Best results are to be expected when steroid administration is started within six months of the onset of the disease and is reserved for those patients with minimal renal lesions. Our data also suggest that life expectancy may be improved, even in patients who do not have a complete remission, if protein excretion can be reduced to less than 2 gm. per day.

The electrocardiogram in potassium depletion: Its relation to the total potassium deficit and the serum concentration

D ESPITE the current widespread interest in the electrocardiogram of potassium depletion, it has not yet been clearly established whether the electrocardiogram is a reliable clinical guide to this condition. Nor has it been determined whether the electrocardiogram is most closely related to the level of serum potassium, the tissue deficit of potassium or to some ratio between these two. The purpose of the present report is to analyze the correlation between these parameters in a group of subjects showing varying degrees of spontaneous or experimental potassium depletion.

Reforming the Health Care System

In a preceding editorial1 I suggested that changing the American health care system to address the basic causes of inflation would be a much better solution to the cost crisis than rationing. Here ...

Salaried Physicians and Economic Incentives

Salaried physicians have recently become an important part of our health care system, and with this change have come new problems for the medical profession and the patients it serves. Not long ago...