C. Giordano

Tubular transport processes in proximal tubules of hypothyroid rats. Lack of relationship between thyroidal dependent rise of isotonic fluid reabsorption and Na+−K+-ATPase activity

Hypothyroid rats reconstituted with 10 μg/kg b.w. per day of tri-iodothironine (T3) for 4 days resulted in normal free T3 and TSH levels. FT3 levels were: 0.53±0.3 pg/ml in hypothyroid rats; 2.78±1.21 pg/ml in hormone reconstituted rats and 2.90±0.90 pg/ml in euthyroid rats. TSH levels were 3,508±513 μg/ml in hypothyroid rats; 1,008±204 μg/ml in reconstituted rats and 270±184 ng/ml in euthyroid rats.When hypothyroid rats were reconstituted with 50 μg T3/kg b.w. per day, TSH levels were nearly normal after 4 days (1,157±621 ng/ml). However FT3 levels after 1–4 days were always higher than in euthyroid rats.Hypothyroid rats show a decrease in isotonic fluid reabsorption (Jv) in the proximal tubule (1.50±0.08 versus 4.96±0.23 10−2 nl·mm−1·s−1 in euthyroid animals). 1 day after T3 (10 μg/kg b.w./day) injectionJv was increased significantly to 2.05±0.20 10−2 nl·mm−1·s−1 and continued to increase during 4 days of T3 reconstitution.When 50 μg T3/kg b.w./day was used,Jv increased to 2.75±0.07 after 1 day and to 3.10±0.42 10−2 nl·mm−1·s−1 after 4 days.Jv was never reaching a value close to that of euthyroid rats because the tubular radius in hypothyroid rats (14.7±1.8 μm) is less than that of euthyroid rats (19.2±0.5 μm). The radius in hypothyroid rats treated with T3 was unchanged over a 4 day course with either high or low doses of T3.Na+−K+-ATPase activity was found to be 2.91±0.16 μM Pi/h×mg protein in homogenates of kidney cortex from hypothyroid rats. Treatment of hypothyroid rats with 10 μg or 50 μg of T3 resulted in an initial decrease in ATPase activity, followed by an increase to base level in hypothyroid rats with 10 μg and a significantly higher level with 50 μg. This decrease in ATPase activity was contrasted to the increase inJv.These data indicate that there is a dissociation between the effects of physiological doses of thyroid hormones on proximal tubular reabsorption and the effects of T3 on Na+−K+-ATPase activity of kidney cortex. This leads to question the relationship between sodium transport and ATPase activity under physiological doses of thyroid hormones. An early effect of physiological doses of thyroid hormones on brush border Na+ permeability is suggested.

Tubular transport processes in proximal tubules of hypothyroid rats

In three groups of rats: control animals (n=18), hypothyroid (TX) rats (n=21) 8–10 weeks after i. p. injection of Na131I (0.4–1 mCi), and hypothyroid rats (n=16) substituted with thyroxine (TX+T3, 50 μg/kg B.W. for 7 days) proximal tubule fluid reabsorption, and transtubular concentration difference of3H-l-histidine and3H-glycodiazine at zero net flux were measured. The effectiveness of TX was confirmed by delayed growth (200±12 as compared to 400±42 g B. W.), diminished plasma concentration of thyroxine (8.0 as compared to 53 μg/l), and increased plasma concentration of TSH (0.75 as compared to 0.15 mg/l).Half time of proximal tubule reabsorption, as measured by the technique of split droplet, was increased (45.8±3.0 s as compared to 18.1±1.0 s in controls). The difference in absolute values of proximal fluid reabsorption was even more marked (1.3±0.1 as compared to 4.7±2.3·10−2 nl·s−1·mm−1) since tubule radius was smaller in TX rats (15.6±0.2 μm) than in controls (19.3±0.5 μm). Substitution with T3 for 7 days did not significantly increase tubule radius (15.7±0.2 μm). Half time of fluid reabsorption, however, was completely normalized (19.4±1.2 s) and thus, absolute value of fluid reabsorption partially restored (3.0±0.2·10−2 nl· mm−1·s−1). The concentration difference of3H-l-histidine (Cperitub−Ctubulc∶Cperitub.) was 0.80±0.03 in controls and significantly decreased in TX rats (0.66±0.03). Administration of T3 to TX rats completely restored histidine reabsorption (0.80±0.03). The concentration difference for3H-glycodiazine in controls (0.84±0.01) was higher than in TX rats (0.81±0.01) and this small difference was restored by T3 administration (0.85±0.01).The data indicate that hypothyroidism strongly affects proximal fluid reabsorption and sodium coupledl-histidine transport and far less the transport of glycodiazine buffer. This suggests that thyroid hormone acts mainly on proximal tubule Na+−K+-activated ATPase.

Histidine for treatment of uraemic anaemia.

A group of 28 uraemic patients on dialysis treatment were given daily supplements of histidine by mouth. Plasma amino-acid concentration, plasma iron, serum transferrin, packed cell volume, and reticulocyte count were all measured before and after two months of histidine supplementation. The treatment raised the plasma histidine concentration and at the same time there was a rise in transferrin and iron levels and packed cell volume. Reticulocyte counts fell after two months of histidine supplementation.

Low protein alimentation normalizes renal haemodynamic response to acute protein ingestion in type 1 diabetic children

Abstract. The effect of an acute protein load (2 g kg‐1bodyweight [BW]) was studied in nine type 1 diabetic children. Patients were maintained on two different dietary regimens. In study one, patients were on a high protein diet providing from 2.7 to 1.8 g of protein/kg of BW per day. In study two, patients were reevaluated after three weeks of a diet providing from 1.0 to 1.2 g kg‐1 of BW per day of protein. In study one (High Protein Diet), we failed to observe any rise in GFR and RPF following the protein meal (137 ± 21 basal vs. 110±14 and 472±93 basal vs. 494±93 ml/1.73 m2 of SA min‐1 at 60 min.

Haematoma of rectus abdominis associated with dialysis.

Colonoscopy subjects the patient to inconvenience and some discomfort. It is time-consuming for the operators and occupies x-ray facilities for long periods, though we estimate that even in the most difficult cases we have used under 45 seconds of screening time. The instrument is costly, requires careful maintenance, and is subject to wear and tear which may lead to damage of the fibre bundle or of the mechanical parts. For these reasons it seems likely that colonoscopy will be a specialist service provided in a few centres. Examination of the whole colon is not to be recommended as an occasional procedure for those with a limited interest in endoscopy. We wish to thank Sister B. Quaid for her skill in preparing the patients and are indebted to Dr. A. C. Young, Mr. A. G. Parks, and Dr. J. E. Lennard-Jones for their advice and support.

Thyroidal Regulation of Alkaline Phosphatase Activity in Kidney Cortex Brush Border Membranes

In kidney cortex homogenates and brush border membranes of hypothyroid rats undergoing T3 substitution with 50 µg/kg BW a day for 1–4 days, a significant decrease of alkaline phosphatase ac

Comparing Schedules of Daily Peritoneal Dialysis

Starting November 1973, peritoneal dialyses have been performed 7 days a week on a group of 18 patients, 11 of whom still on the program. A short daily dialysis technique at a dialysate flow of 2.5 L/hour was used. This group of patients has undergone 9,724 dialyses, 86.8% of which at home.A group of 4 patients had to be switched to hemodialysis. During the last 16 months a total of 5,670 short daily dialyses have been performed, 97.4% of which at home.Another group of 6 patients has undergone Continuous Ambulatory Peritoneal Dialysis (CAPD) for 24 hours daily with 10-liter dialysate containing 3-4.25 g/100 ml dextrose. A total of 967 dialyses have been performed. Peritonitis occurred in 7 instances, and 2 patients had to be switched to hemodialysis.In summary, daily dialysis with either schedule reveals itself suitable for home program and requires a much smaller financial effort from the community. The data presented indicate that CAPD constitutes the most physiological approach to the problem of waste ...

Glucose Metabolism in Acute Renal Failure

Fasting hyperglycemia as well as a prolonged elevation of plasma glucose after both oral (OGTT) and intravenous glucose tolerance test (IVGTT) has been observed in acute uremic patients and in experimentally induced acute uremia in animals (1,2,3).

Thyroid Function in Children on CAPD

Thyroid function in uremia has not been studied as extensively in children as it has been in adults. The data available point to a low T3 and T4 syndrome, but it is not clear whether these patients are hypothyroid or not [1–5]. In addition, little is known about free hormone concentration with respect to the various dialytic modalities for this age group of patients. This work was designed to study thyroid function in children undergoing CAPD. The data presented indicate that CAPD does not correct the low T3 and T4 syndrome. In addition, stunted TSH response to TRH is present.

Hemoperfusion in Diabetic Coma

Hemoperfusion on ionic exchange resins in the therapy of diabetic keto-acidosis (DKA) coma is proposed. Resins used are strong anionic resins in mixed form able to release bicarbonates and to trap ketoanions and organic anions in a stoichiometric manner. A series of trials in open circuit are performed in order to search for a suitable mixture of resins and to establish the amounts of HCO3- and ketoanions respectively released or entrapped. Therefore, ten simulated hemoperfusions in closed circuit systems were performed, utilizing cartridges containing 1,700 g of mixed resin (9% HCO3- form and 91% Cl- form). The results indicate that all side effects of bicarbonate i.v. therapy of DKA coma are avoided because of the smooth HCO3- administration to the patient. Furthermore, a good removal of ketoanions and organic acids is obtained without changing the blood osmolality.