[Estimation of body composition in patients on dialysis by means of near-infrared interaction ]. / Estimering av kroppssammensetning hos dialysepasienter ved hjelp av naer infrarød interaksjon.

Malnutrition and low serum albumin values predict increased mortality in uremic patients. Infrared interactance represents a novel approach to the estimation of body composition. We have examined total body fat, body water and fat-free weight in our male haemodialysis (n = 24) and peritoneal dialysis (n = 17) patients. There were no differences between the groups in a cross-sectional study. A longitudinal study showed a significant increase of total body fat (%) in the peritoneal dialysis patients after five months (mean values +/- SEM) (from 19.8 +/- 2.3 to 22.6 +/- 2.4, p < 0.05), and a significant decrease of body water (%) (from 59.9 +/- 1.5 to 58.2 +/- 1.6, p < 0.05). The difference in total body fat between the haemodialysis (n = 14) and peritoneal dialysis (n = 10) groups reached statistical significance (16.5 +/- 1.7 versus 22.6 +/- 2.4, p < 0.05). No difference was found in serum albumin. Infrared interactance has the capacity to characterize time-dependent differential changes of body composition in various dialysis modalities. Further studies are needed to describe the validity of the method for identification of patients with increasing malnutrition.

[Ultrasonographic evaluation of fat and muscles in patients on dialysis]. / Ultrasonografisk evaluering av fett og muskulatur hos dialysepasienter.

Malnutrition, shown by fat depletion and muscle wasting, is common in uremia. The methods used to describe body composition in uremia are controversial. We have used ultrasonography of the thigh to evaluate fat and muscle in haemodialysis patients (group 1) (n = 14), peritoneal dialysis patients (group 2) (n = 10) and normal controls (group 3) (n = 13). Musculus rectus femoris diameter (0.84 +/- 0.06 cm versus 1.15 +/- 0.08 cm, p < 0.05) and cross sectional area (3.0 +/- 0.4 cm2 versus 5.5 +/- 0.4 cm2, p < 0.01) were significantly reduced in group 1 compared with group 3, as was also muscle area in group 2 (3.9 +/- 0.6, p < 0.05), indicating malnutrition in the dialysis patients. Peritoneal dialysis patients tended to have more subcutaneous fat (p = 0.07) and a larger musculus rectus diameter (p = 0.09) than haemodialysis patients, possibly reflecting better preserved nutritional status. Ultrasonography was equal to computed tomography for estimating these parameters. Ultrasonography is a useful tool for evaluating body composition in uremia, and has a capacity for detection of malnutrition, and possibly for early discrimination between patient groups with different dialysis modalities.

[Severe renal failure during treatment with angiotensin-converting enzyme inhibitors]. / Alvorlig nyresvikt ved behandling med angiotensinkonvertasehemmere.

Three case histories are described which highlight some of the predisposing risk factors and therapeutic strategies in the event of acute severe renal failure during treatment with ACEI. With appropriate therapy, renal function is usually restored within a few days. Renal artery stenosis, dehydration and diuretics stimulate the renin angiotensin system and make preservation of normal renal function, increasingly dependent on angiotensin II. The prevalence of renal artery stenosis is substantially increased in patients with peripheral vascular disease or with coronary artery disease with concomitant hypertension. Patients should be told about the increased risk of adverse effects to the kidneys if they become dehydrated. In these cases it is essential to reduce the dose diuretics and ACEI, and it may be necessary to give parenteral fluid substitution.

Screening for hematuria, glucosuria and proteinuria in people aged 55-64. Technical, clinical and cost-benefit experience from a pilot study.

A total of 754 persons randomly selected from the age group 55-64 years were invited by letter to take part in a screening for hematuria, proteinuria and glucosuria. Each person was asked to provide one sample of morning urine and immediately mail it to the laboratory. A total of 413 persons (55%) responded. Two dipsticks: BM-Test-5L and a new single strip for hematuria determination preliminary named BM 33075 were used, both manufactured by Boehringer Mannheim GmbH. The test strips gave positive reaction for hematuria in 21 persons (5.1%), for proteinuria in 14 persons (3.4%), and for glucosuria in six persons (1.5%). All persons with positive tests were invited to follow-up investigations. In the hematuria group we found one person with a malignant disease, 13 with benign conditions and in seven persons we found no reason for the hematuria. Among those with proteinuria one person had a nephritis. Four persons with glucosuria knew about their diabetes mellitus. The cost of the screening was NOK 99 per participant.

Intrarenal pressure and sodium excretion in hypertension of chronic glomerulonephritis in humans.

The relationship between the fractional excretion of filtered sodium (FENa) and the peritubular capillary physical factors (PCPF) in the hypertension (HT) of chronic glomerulonephritis (GN) was examined in hydropenia (C) and during sustained isotonic saline volume expansion (E; 3% net increase of body weight) in 32 GN patients (16 with HT), and compared with our previous findings in 20 normal individuals (NORM) and 19 patients with essential hypertension (EH). Fourteen GN patients (seven with HT) had a 75% reduction of glomerular filtration rate (GFR), the others (nine with HT) had normal or near normal GFR. The PCPF were estimated from the intrarenal venous (wedged) pressure (IRVP) and the calculated efferent arteriolar protein concentration (EAPC). In C, IRVP correlated to GFR (r = 0.682, p less than 0.001) and (FENa) (r = -0.357, p less than 0.05), but IRVP and EAPC were similar in HT and normotension at comparable levels of GFR. The increase of FENa during E (delta FENa) was exaggerated in all HT groups even at reduced levels of GRF, and could not be related to changes in renal hemodynamics or PCPF. delta FENa correlated with mean arterial pressure in C both in GN (r1 = 0.702, p less than 0.01) and in the combined NORM/EH group (r2 = 0.478, p less than 0.01), with r1 greater than r2 (p less than 0.005). The findings indicate that the pathogenesis of hypertension of chronic glomerulonephritis is independent of changes in the PCPF, and are compatible with the idea that humoral factors are the main mediators of the altered sodium excretion during saline volume expansion in the HT of both chronic GN and EH.

Lung infection caused by Nocardia asteroides in a renal-transplant patient.

A 65-yr-old man developed an acute lung infection while being treated for a rejection episode 2 months after renal transplantation. A chest X-ray revealed a pulmonary infiltrate. Nocardia asteroides was cultured from a percutaneous lung aspirate. The patient was successfully treated with trimethoprim/sulfamethoxazole.

Renal sodium excretion and the peritubular capillary physical factors in essential hypertension.

Peritubular capillary hydrostatic and oncotic forces and their relationship to the renal excretion of sodium (UNaV) were examined in 19 patients with moderate and uncomplicated essential hypertension (HT) and compared with data from 20 normotensive subjects (NT). Observations were made in hydropenia (C) and during sustained isotonic saline volume expansion (E; 3% increase in body weight). The intrarenal venous pressure (IRVP) was used as an index of peritubular capillary hydrostatic pressure, and the efferent arteriolar colloid osmotic pressure (COPeff) was estimated from the arterial COP and the filtration fraction. C values (mean +/- SEM) in HT (and NT) were: arterial pressure (MAP) 110 +/- 3 mm Hg (85 +/- 1, p less than 0.001); glomerular filtration rate (GFR) 122 +/- 4 ml/min/1.73 m2 (128 +/- 3, p greater than 0.05); renal blood flow (RBF) 1172 +/- 38 ml/min/1.73 m2 (1298 +/- 48, p less than 0.05); IRVP 25.0 +/- 1.0 mm Hg (24.8 +/- 0.8, p greater than 0.05); COPeff 33.0 +/- 0.7 mm Hg (31.9 +/- 0.6, p greater than 0.05); and UNaV 140 +/- 13 mumole/min (161 +/- 12, p greater than 0.05). During E, the increase of UNaV in HT was more than double that of NT (p less than 0.001) while IRVP did not change in either group (p greater than 0.05); and COPeff fell by 26% (p less than 0.001) in both groups. GFR and RBF increased by 18% (p less than 0.001) and 19% (p less than 0.001) respectively, in HT, but did not change in NT. MAP remained unchanged in both groups. The results indicate that the peritubular capillary physical factors are normal in established essential hypertension, and that these forces are not involved in the exaggerated natriuretic response to volume expansion in essential hypertension.

Intrarenal venous and cortical catheter pressures in the dog kidney.

To examine the validity of intrarenal venous pressure (IRVP) as a measure of peritubular capillary pressure when obtained with a method applicable in man, IRVP was measured with a 0.9 mm o.d. catheter introduced retrograde into interlobar veins of anesthetized dogs and was compared with a modified needle pressure (cortical catheter pressure = RCCP) measured simultaneously in the same kidneys. In twelve dogs with a mean experimental kidney control sodium excretion of 91 +/- 15 (SEM) micronmol/min IRVP averaged 16.0 +/- 1.1 mmHg and was significantly lower than the average RCCP of 22.6 +/- 1.1 mmHg (P less than 0.001). These pressures compare well with the reported micropuncture pressures in the peritubular capillaries and proximal tubules, respectively, at comparable levels of sodium excretion. IRVP fell significantly during reduction of renal perfusion pressure within the range of autoregulation of renal blood flow and increased during elevation of renal pelvic pressure (PP). At at PP of 60 mmHg, when urine flow had stopped, the PP-IRVP gradient was 22.7 +/- 3.1 and increased to 36.7 +/- 3.8 (P less than 0.001) at a PP of 80. Acute renal vein constriction always increased IRVP before renal vein pressure reached the preceeding control level of IRVP. Increased urine flow during saline volume expansion and furosemid infusion was associated with increased IRVP. The results when compared with micropuncture data indicate that IRVP is a satisfactory expression of peritubular capillary pressure in the experimental conditions included in the study.

Postglomerular vascular hydrostatic and oncotic pressures during acute saline volume expansion in normotensive man.

The importance of the peritubular physical factors as mediators of the natriuretic response to saline volume expansion was examined in twenty normotensive, hydropenic indivduals. Intrarenal venous pressure (IRVP), used as a measure of peritubular capillary hydrostatic pressure, and efferent arteriolar colloid osmotic pressure, calculated from arterial colloid osmotic pressure and the filtration fraction, were measured before and during sustained volume expansion with 0.9% NaCl, increasing the body weight by 3% and plasma volume about 20%. During expansion there was a significant increase in urine flow from 1.1 +/0 0.1 to 3.1 +/- 0.4 ml/min and sodium excretion from 161 +/- 12 to 551 +/- 61 microEq/min. Efferent colloid osmotic pressure fell from 31.9 +/- 0.6 to 23.6 +/- 0.5 mmHg (P less than 0.001) while IRVP changed from 24.8 +/- 0.8 to 25.1 +/- 0.9 mmHg (P greater than 0.10). In eight individuals IRVP increased during saline loading but later fell during sustained expansion. Glomerular filtration rate and renal blood flow did not change significantly. It is concluded that increase in peritubular capillary hydrostatic pressure is not necessary either to induce or to maintain the natriuresis of a moderate saline volume expansion. Although the fall in postglomerular vascular colloid osmotic pressure is a possible mediator of the natriuretic response, the change in peritubular transcapillary net driving force produced by a modest saline volume expansion is probably small.

Assessment of barbiturate removal by charcoal hemoperfusion in overdose cases.

Five patients with severe barbiturate intoxication were treated with charcoal hemoperfusion. The perfusions were carried out for 3.5 hr, two of the patients requiring an additional treatment. A marked clinical improvement was observed in all of the patients. The serum concentration decreased by 17 to 42% and the amount removed corresponded to 4 to 13% of the ingested dose. The clearance decreased from the start to the end of the treatment during most of the perfusions. With phenobarbital the clearance was less reduced and the column still had the capacity to adsorb drugs after the 3.5-hr perfusion. Therefore, since the amount of drug removed was relatively small, longer lasting perfusions are recommended.

Diameter of afferent arterioles during autoregulation estimated from microsphere data in the dog kidney.

Afferent arteiolar diameters, relative flow distribution, and flow conductance factors are estimated by nonlinear regression analysis of the sieving effect on microspheres in different vascular structures of the dog renal cortex. The data presented are from experiments in which microspheres of 10-30 microgram were injected into the abdominal aorta during normotension and after lowering the blood pressure to the lower limit of autoregulation. Microscopic examination of the spheres trapped in the glomeruli and the renal arteries showed an increasing exclusion of microspheres greater than 15 micrometer from the afferent arterioles during normotension. This effect was most pronounced for the deeper cortical layers and can be explained mainly as geometrical exclusion of spheres from afferent arterioles. During hypotension, progressively larger microspheres entered glomeruli and afferent arterioles, presumably due to vasodilation of the vessels. There was a significant redistribution of microspheres larger than 15 micrometer from the outer to the inner cortex during hypotension without a corresponding redistribution of smaller spheres or the estimated blood flow. Approximately the same degree of dilation of afferent arterioles was observed during autoregulatory hypotension in three cortical layers.

Membrane filtration in microscopical examination of urinary sediment.

Microscopical examination of the urinary sediment has been performed after membrane filtration and after routine centrifugation, and the results were compared. Various quantities of urine were filtered through a membrane with pore size of 3 micrometer, stained with Shorr stain and made translucent with xylol. All granular and cellular casts were counted on a trimmed membrane, 15 X 20 mm. The routine centrifugation was carried out on 10 ml urine at 1500 rpm for 3 min. Among 11 patients with glomerulonephrits and recurrent hematuria, casts were found in 9 after filtration but in only 2 after routine centrifugation. Casts were detected by the filter method in the urine after angiography of the kidneys in 8 of 12 patients, after centrifugation in only one of them. No casts were found in 6 patients with hematuria due to urological disorders and in 21 healthy persons. The diagnostic sensitivity of microscopical examination of urine was greatly increased by the filter method. This may be due to larger amount of urine examined by the filter method, but an additional cause may be that routine centrifugation destroys red cell casts.

Renal extraction of endogenous gastrin in patients with normal renal function.

Renal extraction of gastrin in patients with normal clearance of inulin and p-aminohippuric acid was assessed by gastrin radioimmunoassay. In 23 fasting patients there was no significant difference in arterial gastrin (37.7 pg/ml serum +/- 25.1 S.D.) and the renal vein gastrin (35.9 +/- 24.6), resulting in a renal extraction ratio for gastrin not significantly different from zero (p greater than 0.5). The results in three patients indicated no extraction of gastrin for two consecutive periods after a protein-rich meal.

Effect of steric restriction on the intracortical distribution of microspheres in the dog kidney.

The effect on the intracortical distribution of microspheres and radioactivity caused by steric hindrance of the free movement of spheres into afferent arterioles are described by two mathematical models. The results are compared with corresponding experimental data obtained in six kidneys from normotensive dogs. The first model (A) assumes that spheres are distributed as blood flow, regardless of their size, except for those having diameters greater than that of an afferent arteriole and which do not enter this vessel. The second model (B) includes the Ferry correction. The experimental data show that the percent recovery of spheres with diameters of 20-25 mum was significantly greater in the outer cortex and significantly less in the juxtamedullary cortex than recovery of the smaller spheres, and that the distribution of spheres with diameters of 10 mum to about 17 mum seems uninfluenced by the sphere size. The experimental results we have obtained fit best with model A. We found that according to both models steric restriction is a factor of major importance in relation to the intracortical distribution of spheres, and the analysis shows that the blood flow in the inner part of the renal cortex is grossly underestimated by the method of isotope labeled microspheres when diameters of 15 +/- 5 mum are used in the dog. Furthermore we found that dilation of the afferent arterioles will change the steric hindrance so that a redistribution of spheres and radioactivity may occur without any redistribution of blood flow. It is suggested that the results interpreted as redistribution of blood flow can be explained as due to altered steric hindrance alone, i.e., as a methodological artifact.