Vascular and glomerular changes in the ageing kidney

Glomerular size, shape and number were examined in 44 human kidneys obtained at necropsy. Intrarenal vascular appearances were assessed histologically and by post-mortem angiography. The mean cross-sectional area of glomeruli varied nearly three-fold and glomerular number varied more than three-fold when kidneys from different adult subjects were compared but kidneys from the same subject resembled one another in glomerular size and number. A significant negative correlation existed in the adult between glomerular number and dimensions. Glomerular numbers in the few immature kidneys studied were similar to those in adult kidneys but glomeruli were smaller. Glomerular numbers tended to decline as age and severity of age-related vascular changes increased but correlation was poor. The possibility remains that glomerular involution in the senescent kidney occurs independently of events in the vessels. In men, but not in women, totally hyalinised glomeruli were observed more frequently with increasing age but their presence did not appear to be related to the degree of vascular change. In the senescent kidney, glomerular lobulations tended to disappear. This, together with glomerular loss, must result in a reduction in the area available for filtration. Assessments of total glomerular surface area should take account of glomerular shape and dimensions as well as numbers.

Effect of rotation on radiographic dimensions of the humerus and femur

Ten humeri and ten femora were radiographed in nine positions of longitudinal rotation. In each position total, medullary and cortical widths of the diaphyses (TW, MW, CW) were measured to assess the effect of rotation on these dimensions. The results were expressed as differences from the values in the neutral position (delta TW, delta MW, delta CW). In the humerus, medial rotation produced greater changes than lateral rotation. Though rotation in either direction increased CW, the systematic error due to medial rotation to only 5 degrees (approximately +0.0058 cm per degree) was more than double that due to lateral rotation. In the femur, lateral rotation had the greater effect, producing a marked decrease in CW (approximately -0.0072 cm per degree). Medial rotation produced only a slight increase in CW. The ratios CW/TW ("cortical index") and CA/TA ("area ratio") were calculated and expressed as differences from the values in the neutral position (delta CW/TW, delta CA/TA). Rotation affected these variables much less than the linear dimensions. Furthermore, through the variance of delta TW, delta MW and delta CA/TA increased only slightly or not at all. These results suggest that if radiographic morphometry is to be applied to the humerus and femur, these ratios rather than transverse dimensions should be used. Sequential changes in CW may be totally obscured by small rotational errors.

Effect of long-term diuretic treatment on body-potassium in heart-disease

Plasma and total body potassium have been measured in 151 patients with chronic heart-disease, 83 of whom were taking diuretics and potassium supplements. After allowance for age and body-size, the deficit in total body-potassium was only 3-5% (100-150 mmol) in the diuretic group. 13 of the 83 patients taking diuretic had hypokalaemia (less than 3-5 mmol/1) but the potassium deficit was no greater than in the patients with normal plasma-potassium. There was no relation between the dose of potassium supplements and either the plasma-potassium or the total body-potasium. It is suggested that potassium depletion is not a major problem in patients with heart-failure treated with diuretics. The dose of potassium supplements should therefore be determined entirely by the plasma-potassium.

Estimation of glomerular size and number from radiographs of the kidney

In 32 adult human kidneys obtained at necropsy, renal demensions, measured from radiographs, were correlated with the number and cross-sectional area of glomeruli, determined by point-counting and computerized image analysis. Cortical area, measured from post-mortem angiograms, was poorly correlated with glomerular area and was not significantly correlated with glomerular number per kidney. The area of the whole kidney was poorly correlated with the number of glomeruli per kidney and was not significantly correlated with glomerular area. However renal dimensions, particularly total renal area, were highly significantly correlated with the product of glomerular area and number. This may allow glomerular numbers to be estimated in life but will not assess loss of glon the ageing kidney, the number of glomeruli per unit volume increased.

Autotransplantation of the kidney for fibromuscular dysplasia of the renal arteries

A young man was discovered to have symptomless hypertension, which subsequently proved to be caused by fibromuscular dysplasia of the renal arteries. Arterial disease was present on both sides but was more severe on the right. Samples of blood were obtained by selective catheterisation of each renal vein for the determination of plasma renin activity. The renal venous renin was greater on the right than on the left (ratio greater than 1-5 to 1) and secretion of renin by the left kidney was suppressed. Autotransplantation of the right kidney to the left internal iliac artery lowered the blood pressure at once and it has remained normal for 6 months. The implications of this procedure for the management of a bilateral disorder of the renal arteries, such as fibromuscular dysplasia, are discussed.

Nephrographic density and renal diatrizoate content in experimental acute renal failure

Reversible acute renal failure (ARF) was induced in rats by intramuscular injection of glycerol. In these animals and controls, renal concentrations of 125I-labelled sodium diatrizoate, injected intravenously in doses similar to those used clinically, were compared with the density of the nephrogram, subjectively assessed under carefully controlled conditions. Though a good statistical correlation existed between renal diatrizoate concentration and nephrographic density, individual variation was wide. At any given level of renal iodine concentration, nephrograms were judged to be denser in ARF than in controls. This was not due to differences in whole-body opacification or renal size, but was partly explained by the greater visibility of renal outlines on plain films in ARF. However, though at all doses of diatrizoate renal iodine concentrations were higher in controls, differences in nephrographic density were in general difficult to detect.

Effect of dose on renal diatrizoate concentrations in experimental acute renal failure

In rats with glycerol-induced acute renal failure (ARF) and controls, renal concentrations of 125I-labelled sodium diatrizoate were measured 5 min after intravenous doses ranging from 14 to 1,800 mg/kg body weight. Renal concentrations of diatrizoate, at all doses, were much higher in controls than in ARF. A linear relationship existed between dose and renal concentration in ARF. In controls, at doses above 225 mg/kg body weight, the fraction of the dose present in the kidneys diminished and renal iodine content approached that observed in ARF. Differences in diatrizoate concentration which existed between cortical and medullary zones in healthy kidneys at low dises were progressively eliminated as dosage increased, consistent with the osmatic fiutryiv rggrvy of diatrizoate. In ARF, the pattern of intrarenal distribution at all doses was similar to that seen in controls at high doses, though concentrations in outer cortex were consistently slightly higher than those in inner cortex. These observations suggest continuing though reduced, filtration of diatrizoate in ARF by glomeruli already subjected to a large solute load.

Urinary tract in schoolgirls with covert bacteriuria

During screening of 16,800 primary schoolgirls, aged 4-12 years, in Cardiff and Oxford, significant bacteriuria was found in 294 (1-7%). Intravenous urography and micturating cystography were performed in 246 of these girls. The urinary tract was abnormal in 47%. Pyelonephritis with or without vesicoureteric reflux was present in 26% and reflux without renal abnormality in a further 16%. The prevalence of pyelonephritis and reflux was independent of age. With few exeptions kidneys without pyelonephritic scars appeared to be normal in size, even when ureteric reflux was present.

Radiological diagnosis of crocidolite induced pleural mesotheliomata in the rat

Crocidolite asbestos dust was inoculated intrapleurally in 36 rats. Chest radiographs were obtained up to 120 weeks after inoculation. Radiological and pathological observations were compared. In 3 animals, in which mesotheliomata were suspected radiologically, no evidence of malignancy was observed on histological examination. A radiological diagnosis suggesting probable or definite malignancy was made in all 7 animals with histologically proven mesotheliomata.

Progressive kidney damage after non-obstructive urinary tract infection

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Portal venous injection in the rat

A technique for subcutaneous transposition of the spleen in the rat is described. The preparation has been developed as a reliable means of transplenic portal injection. It has been shown that different substances injected into the pulp of the transposed spleen are cleared and not pooled in the organ. The development of porta-systemic venous communications has been demonstrated and their detection radiologically and by isotope techniques is illustrated. It is suggested that the technique outlined in this communication may be of value in the study of the portal circulation, the function of the liver, and in the investigation of drug action.If adequate porta-systemic venous connexions are present the portal vein can be tied above its splenic tributary and the animal will survive. The method offers a simple means of porta-systemic diversion in the rat.

Polytome encephalography in investigation of pituitary tumours

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Serum growth hormone levels and size of pituitary tumour in untreated acromegaly

Serum levels of growth hormone were measured in 84 untreated acromegalic patients. The range of mean level during a glucose tolerance test was 8 to 1,860 ng./ml. and was lognormally distributed. Mean level was reproducible and correlated moderately well with maximum sellar area on lateral tomography. The hormone level was more responsive to oral glucose and insulin-induced hypoglycaemia in patients with smaller tumours. Attention is drawn to limitations of plain radiographs in assessing the size of a pituitary tumour. Suprasellar tumour extensions may be present in patients without visual field defects.