George B. M. Lindop

Collagen-linked fluorescence in human atherosclerotic plaques

Advanced glycosylation endproducts (AGE) are intraprotein crosslinks which form in the late stages of the Maillard (browning) reaction. It is unknown whether local changes in AGE-modified collagen occur within arteries. We measured AGE-modified collagen as collagen-linked fluorescence (CLF) in human arterial tissue and in various forms of atherosclerotic plaque. All tissues showed single fluorescence peak at excitation wavelength 340 nm and emission wavelength 420-440 nm. CLF in the aorta was 27.9 +/- 8.5 units/mg, in the coronary arteries 25.9 +/- 6.3 units/mg and in the tendon 47.8 +/- 11.5 units/mg. CLF in the skin correlated with CLF in the aorta (r = 0.467, P = 0.025) but not with CLF in coronary arteries (P = 0.935). In areas of aorta covered by superficial plaque, CLF was decreased compared with adjacent, atheroma-free segments (22.2 +/- 5.2 units/mg vs. 27.9 +/- 8.5 units/mg; P = 0.01). The CLF of collagenous plaques correlated with CLF of the atheroma-free regions. Individuals with low to moderate atheroma had lower (20.0 units/mg) CLF in superficial atherosclerotic plaques than patients with severe atheroma (22.5 units/mg; P = 0.0466). Our results indicate that local changes in vascular AGE-collagen concentration occur in atherosclerosis. This finding may have pathogenetic significance in atherosclerosis.

The distribution of renin‐containing cells in kidneys with renal artery stenosis—an immunocytochemical study

In 10 kidneys removed for hypertension due to renal artery stenosis, the histological appearances varied from negligible ischaemic damage to end‐stage ischaemic atrophy. We stained the renin‐containing cells in tissue sections using an antiserum to pure human renin and an immunoperoxidase technique. In all kidneys there was hyperplasia of the renin‐containing cells both in juxtaglomerular apparatuses (JGAs) and in arteries outside the JGA, where these cells extended proximally as far as the Interlobular arteries. We mapped the distribution of renin‐containing cells and found them in all zones of the renal cortex; in three kidneys they were predominantly in the superficial cortex; in four they were distributed more evenly throughout the width of the cortex; but in three kidneys the normal gradient was reversed, with most of the cells being in the juxtamedullary cortex and, in two of the cases, little or no stainable renin in the superficial cortical JGAs. We suggest that these abnormalities in the distribution of renin‐containing cells could affect both the pattern of intrarenal blood flow and the site in the kidney at which secreted renin enters the blood.

Ectopic thyroid tissue on the ascending aorta: an operative finding

We describe a case of benign ectopic thyroid tissue found attached to the ascending aorta at operation.

Distribution of renin-containing cells in the developing human kidney : an immunocytochemical study

Objective To characterize the pattern of renin containing cells (RCC) within the human kidney between 20 weeks of gestation and 6 months of postnatal life.

The renin-secreting cell in polyarteritis--an immunocytochemical study.

We studied kidney sections from 15 cases of polyarteritis using an immunocytochemical technique to demonstrate cells containing immunoreactive renin. Ten cases of classical polyarteritis nodosa showed hyperplasia of renin‐containing cells in areas of renal cortex with histological evidence of ischaemia—appearances indistinguishable from those seen in renal artery stenosis. Histologically normal cortex showed little or no immunostainable renin. In the ischaemic areas there was loss of the normal gradient of renin‐containing cells from superficial to deep cortex. In many cases this gradient was abolished or even reversed; in some cases most renin‐containing cells were in juxtaglomerular apparatuses. This alteration in the distribution of immunoreactive renin has only been described in renal artery stenosis in man. In five cases of microscopic polyarteritis there were fewer than normal numbers of renin‐containing cells.

A case of neonatal Bartter’s syndrome

Abstract. We describe a child with a neonatal presentation of Bartter’s syndrome. Unlike infants previously described with a similar clinical presentation, the urinary excretion rate of prostaglandin E2 in this child was similar to normal children and Tamm-Horsfall protein was distributed normally in the thick ascending limb of the loop of Henle. The child failed to respond to indomethacin alone, but thrived after the addition of the angiotensin converting enzyme inhibitor, captopril.

IN VIVO STUDIES OF THE CONTROL OF DNA SYNTHESIS IN THE RAT ADRENAL CORTEX AND MEDULLA

The control of zonation in the adrenal cortex has been studied by measuring DNA synthesis using an analogue of thymidine, bromodeoxyuridine (BrDUrd). Groups of rats were infused with BrDUrd for 10-14 days whilst being treated with: high or low sodium diets; captopril; angiotensin II; dexamethasone; an inhibitor of nitric oxide synthesis, L-NAME. DNA synthesis in the zona glomerulosa was increased by low sodium food and angiotensin and was decreased by dexamethasone, captopril L-NAME and a high sodium diet. Dexamethasone, not manipulations of the renin-angiotensin system, affected DNA synthesis in the outer zona fasciculata. The BrDUrd index in the zona intermedia was unaffected by any of the treatments and was generally lower than in adjacent zona fasciculata and zona glomerulosa cells. Cells of the zona reticularis appeared to be regulated independent of the zona fasciculata. BrDUrd uptake in nuclei of the adrenal medulla was inversely related to blood pressure. We conclude that DNA synthesis in each adrenocortical zone is independently controlled. Migration of cells within zones after proliferation is likely.

Modulation of the Autoimmune Response in Lupus Mice by Oral Administration of Attenuated Salmonella typhimurium Expressing the IL-2 and TGF-β Genes

A meeting analyze on human and animal B lymphocyte subsets, their function, and their signaling pathways in relationship to autoimmunity held in Prague, the Czech Republic.

A comparative study of the glomerular peripolar cell and the renin-secreting cell in twelve mammalian species

The peripolar cell is a glomerular epithelial cell situated within Bowmans capsule at its vascular pole. It is believed to be a secretory cell which forms part of the juxtaglomerular apparatus. Scanning electron microscopy was used to perform a comparative study of the morphology and number of peripolar cells in twelve mammalian species. The number of renin-secreting cells in kidney sections stained by renin antibodies and immunocytochemistry was counted. There was a marked inter-species variation in the number, size and appearance of peripolar cells. They were largest and most abundant in sheep and goat and fewest in dog, cow and human. There was no correlation between the numbers of peripolar cells and renin-secreting cells. This does not support the view that the peripolar cell is part of the juxtaglomerular apparatus.