Uncoupling of oxidative phosphorylation does not induce thermotolerance in cultured Chinese hamster cells.

Two uncouplers of oxidative phosphorylation, 2,4-dinitrophenol (DNP) and carbonyl cyanide m-chlorophenylhydrazone (CCCP), were tested for their ability to modify the survival of cultured Chinese hamster ovary (CHO) and Chinese hamster V79 cells treated with hyperthermia. The uncouplers were used under conditions that inhibit oxidative ATP synthesis, as judged from measurements of cellular ATP levels. Incubation of CHO cells in glucose-free Hanks' balanced salt solution (HBSS) containing 1 mM DNP for 1 h at 37 degrees C followed by reincubation at 37 degrees C in complete growth medium for 3 or 16 h, showed no substantial changes in the 45 degrees C heat survival curve as compared to heated cells not exposed to DNP. Thus, DNP treatment of CHO cells did not induce thermotolerance. Carbonyl cyanide m-chlorophenylhydrazone (CCCP), tested under similar experimental conditions, did alter cellular heat resistance. The major change in the 45 degrees C survival curve of CHO cells pretreated with CCCP was an increase in the width of the shoulder: the Dq value increased from 14 min to 24 min, for the control and CCCP-treated cells respectively. The D0 value did not change appreciably. In contrast, heat-induced thermotolerance (10 min, 45 degrees C + 16 h, 37 degrees C) was characterized primarily by an increase in the D0 parameter from 4 min (unheated cells) to 17 min. Similar results were observed with CCCP-treated V79 cells. The data demonstrate that heat resistance induced by 1.2 microM CCCP was manifest as an increased cellular capacity to accumulate and/or repair hyperthermia damage, rather than an induction of thermotolerance, and that this effect probably was not related to the action of CCCP as an uncoupler of oxidative phosphorylation.

Development of thermotolerance in CHO cells: modification by procaine.

We have tested the reported ability of procaine to inhibit the induction and the development of thermotolerance in Chinese hamster ovary cells. Thermotolerance was induced either by hyperthermia alone (10 min, 45 degrees C) or by combining hyperthermia and procaine (5 min, 45 degrees C + 10 mM procaine) with heating times adjusted to yield similar cell survival after the conditioning treatments. Both the kinetics of thermotolerance development in fresh medium without procaine and the magnitude of thermotolerance 6 h after heat conditioning were similar for the two treatment groups. Development of thermotolerance in the presence of procaine was tested by adding the drug at 5 or 10 mM to culture medium between, but not during two fractionated heat treatments. Thermotolerance development was observed even in the presence of 10 mM procaine, but only if cell survival was corrected for the 37 degrees C-procaine toxicity. Complete survival curves of cells incubated for 6 h at 37 degrees C in 7.5 mM procaine between heat conditioning and test heating showed a D0 that was only 35 per cent lower than that of thermotolerant controls. The data are consistent with the reported sensitization to heat killing by procaine, but show that thermotolerance induction and development were only minimally perturbed by procaine.

Response to pneumococcal vaccine in renal allograft recipients.

Pneumococcal vaccine, 14-valent, was administered to 75 stable adult renal transplant patients on maintenance immunosuppression. 32 had undergone splenectomy prior to transplantation and 43 had not. Functional opsonizing antibody was measured by chemiluminescence methodology for types 12F and 14, contained in the vaccine, and for type 5, a control strain. Serum was examined prior to and at 1 and 6 months after vaccine injection. 33, 71, and 35% of transplant patients had preexisting antibody to types 5, 12F, and 14, respectively, as compared to 58, 87, and 68% of controls. No differences were observed in nonsplenectomized versus splenectomized patients. Following immunization, 59 and 76% of antibody-negative patients converted to positive for pneumococcus type 12F and 14. These included 70 and 70% for nonsplenectomized patients as compared to 50 and 84% for those splenectomized. Vaccination did not result in the production of opsonizing antibody for the related type 5 pneumococcus. Pneumococcal vaccine generates functional antibody and is safe in renal transplant patients.

Effect of furosemide on urinary acidification in distal renal tubular acidosis.

Furosemide stimulates urinary acidification in normal humans probably by increasing distal Na delivery and transport, thus creating a favorable electric gradient for H+ and K secretion. Therefore, furosemide should stimulate urinary acidification in patients with distal renal tubular acidosis, provided the distal nephron is capable of transporting Na and the H+ pumps can respond to the favorable electric gradient. We examined the effect of short-term furosemide administration on urinary acidification in five normal participants and 12 patients with normokalemic, hypokalemic, or hyperkalemic distal renal tubular acidosis. In controls, furosemide decreased urine pH and increased net acid and K excretion. In six of eight patients with normokalemic or hypokalemic renal tubular acidosis, furosemide decreased urine pH and increased net acid and K excretion to levels not significantly different from control values. The patients that had normal responses were interpreted as having a rate-dependent or gradient distal renal tubular acidosis, and thus increased distal Na delivery created a favorable electric gradient for H+ and K secretion. The normokalemic patients who did not have a response were considered to have a defect in the pumps (secretory defect). Of the four hyperkalemic patients, two had a voltage-dependent defect and the other two had aldosterone deficiency. The patients with selective aldosterone deficiency had low baseline urine pH values that did not change with furosemide administration, but net acid and K excretion did increase significantly. The patients with voltage-dependent defect did not lower urine pH or increase net acid and K excretion. Our data demonstrate that administration of furosemide enhances urinary acidification in certain patients with distal renal tubular acidosis. We suggest that furosemide administration may be useful in the characterization of the mechanism responsible for distal renal tubular acidosis and in the treatment of distal renal tubular acidosis in selected patients.

Fanconi's syndrome associated with carburetor fluid intoxication.

A patient who ingested carburetor fluid developed methanol intoxication followed by hypouricemia, hypophosphatemia, glycosuria, and hyperchloremic metabolic acidosis. Renal clearances of phosphate, uric acid, glucose, and bicarbonate were found to be elevated indicating the presence of Fanconi's syndrome. The authors postulate that the Fanconi's syndrome observed in our patient was the result of the organic solvents present in the mixture.

Bilateral ureteral obstruction following aortic bypass surgery.

A patient developed azotemia from bilateral ureteral obstruction due to retroperitoneal fibrosis after placement of an aortofemoral bypass graft for atherosclerosis in that region. This complication of abdominal vascular prosthesis may be more common than is presently recognized; especially since the patient may remain asymptomatic till an advanced degree to azotemia supervenes. At that time irreversible damage to the kidney may occur. Furthermore, silent damage in the kidneys may be attributed to other causes in these patients who may also have severe vascular disease or prostatic disease. When a gradually increasing azotemia is seen in a patient who had aortofemoral bypass surgery, ureteral obstruction from retroperitoneal fibrosis should be one of the main considerations in the differential diagnosis. Computed tomography, isotope renography and sonography may be helpful in making an early diagnosis and should be a part of the postoperative follow-up care in these patients.

Vancomycin penetration into CSF during treatment of patients receiving hemodialysis.

Penetration of vancomycin into CSF was determined during therapy with the regimens recently used to treat staphylococcal infections in patients receiving hemodialysis: 1 gm weekly or 750 mg twice weekly. During three episodes in two patients with proved or suspected central nervous system infection, CSF levels of vancomycin ranged from < 0.5 to 1.54 microgram/ml; in only two of six CSF specimens did the antibiotic level exceed its in vitro inhibitory concentration for the infecting organism. Thus, the vancomycin hemodialysis regimens may provide marginal to subtherapeutic CSF drug levels.

Comparison of inulin, iothalamate, and 99mTc-DTPA for measurement of glomerular filtration rate.

Clearances of inulin, 125I-iothalamate, and 99mTc-Sn-DTPA were measured simultaneously in five mongrel dogs exhibiting a wide range of glomerular filtration rates (GFR). Standard constant-infusion inulin clearance was compared to radionuclide clearances after subcutaneous injection of the emitters mixed with aqueous epinephrine. All three substances were found to have virtually identical clearances. The accuracy, accessibility, low cost, low radiation hazard, and short half-life of 99mTc-Sn-DTPA make it an excellent substance for measuring GFR. The subcutaneous technique offers an accuracy comparable to the more difficult constant-infusion method.

The effect of dietary sodium chloride on blood pressure, body fluids, electrolytes, renal function, and serum lipids of normotensive man.

Eight normotensive white middle-aged men were given low, moderate, and high salt diets with constant potassium intakes each for periods of at least 4 weeks. There was a tendency for body weight, serum sodium, exchangeable sodium, and inulin space to increase. Indirect blood pressure measurements revealed no change in blood pressure, either supine or upright measurements, during the 3 study intervals. Inulin clearance (and presumably glomerular filtration rate) rose with increase in dietary salt. Urinary potassium excretion rose progressively as salt intake increased. Total body potassium tended to decrease with increase in dietary salt. There was no changes in the excretion of calcium, magnesium, phosphorus, nor were there changes in the blood level of potassium. There was no change in total body water. The serum cholesterol and triglyceride levels were not appreciably affected by the different dietary sodium intakes. Plasma renin activity and urinary aldosterone excretion rose progressively with the two levels of sodium restriction. These studies indicate that normal man is able to compensate for large differences in sodium intake with minor metabolic changes. These changes do not necessarily lead to hypertension over a one-month period. Nevertheless, many hemodynamic and hormonal compensatory mechanisms come into play. It is evident that hypertension might result should the sodium load not be excreted, the circulating volume become too great for the excretory capacity, or if neural or endocrine adjustments be inadequate.

Study of proteins and fibrinolysis in patients with glomerulonephritis.

Plasma and urine fibrinolysis were studied in 36 patients with glomerulonephritis and proteinuria. In 40% of these plasma fibrinolytic activator activity was moderately reduced and fibrinolytic inhibitors were increased. Globulins with antiplasmin effect were raised, particularly in the earlier months. Both the serum cholesterol and the plasma fibrinogen were related to the level of serum albumin, and those patients with high fibrinogen levels were also those with poor plasma fibrinolytic activator and those showing a steady deterioration. Urinary fibrinolysis was greatly reduced in most patients and bore no relation to plasma fibrinolysis levels. Hence urokinase is not derived from circulating plasminogen activator.