2-Bromoethanamine nephrotoxicity in the nude mouse: an atypical targetting for the renal cortex

Male MF1-nu/nu/Ola/Hsd nude mice, maintained in a gnotobiotic environment, were dosed i.p. with either 50, 100 or 200 mg/kg 2-bromoethanamine (BEA) hydrobromide to induce a model papillary necrosis. Renal histological changes were examined in semithin glycolmethacrylate resin sections at 24, 48 and 72 h after BEA treatment. The sequence of medullary changes included pyknosis of interstitial cell nuclei, increased staining of the interstitial mucopolysaccharide matrix, platelets adhering to capillary endothelium, necrosis of collecting duct epithelial cells and denudation of the covering epithelium of the papilla. This was similar to that previously described in the Wistar rat, but the time course was extended. There was also a concomitant and extensive cortical necrosis of the P2 and P3 segments of the proximal tubule, which was evident prior to the onset of renal papillary necrosis at the higher doses of BEA. Nude mice show an atypical response to BEA compared to several mouse and rat strains, the hamster and pig, that suggests unique characteristics in this athymic murine mutant.     

The effects of chronic papillary necrosis on acid excretion

Complete papillary necrosis in rats can be induced within 1 month following a single injection of 2-bromoethylamine hydrobromide (BEA) (50 mg, i.v.). Utilizing a combination of clearance and balance techniques the effects of complete absence of the papilla was examined as regards urinary acidification, whole kidney glomerular filtration rate (GFR), single nephron GFR, and morphology. Whole kidney GFR was not different from control, however, the percent filtering juxtamedullary nephrons was markedly diminished (87.2±2.1 vs. 31.5±3.6% filtering, control vs. BEA, respectively,P<0.001) and significantly reduced in the superficial nephrons (80.6±3.6 vs. 62.2±6.1% filtering, control vs. BEA, respectively,P<0.05). There was a significant decrease in juxtamedullary single nephron GFR and an increase in the superficial single nephron GFR as assessed by the quantitative Hanssen's technique in the animals with chronic papillary necrosis. Complete papillary necrosis was associated with normal arterial bicarbonate concentration, pH, and plasma electrolyte concentrations. At the same degree of acidemia (induced by NH₄Cl administration) minimal urinary pH, ammonium excretion, and titratable acid excretion were not different than seen in age matched controls. The response to Na₂SO₄ infusion and phosphate infusion was the same in both groups of animals. The urineblood (U-B)pCO₂, an index of urinary acidification, was identical in BEA and control animals. Scanning electron microscopy showed scarring of the juxtamedullary glomeruli one month after BEA. The papilla was sloughed and lying free in the renal pelvis in every experimental animal. These data demonstrate that complete papillary necrosis is not associated with acidosis nor a defect in urinary acidification.     

Unilateral papillary necrosis complicating renal artery stenosis—evidence of activation of the intrarenal renin–angiotensin system?

We report an association between renal artery stenosis and papillary necrosis. We studied three kidneys with renal artery stenosis, two of which showed ipsilateral acute papillary necrosis. In all three cases there had been a sudden fall in perfusion of the ischaemic kidney. In the case with intact papillae, immunostainable renin was normal in amount and distribution, whereas both kidneys with papillary necrosis showed hyperplasia of renin-containing cells, and these were mainly in the JGAs of the juxtamedullary cortex. Since the contralateral kidneys were spared, we suggest that in an ischaemic kidney with hyperplasia of renin-secreting cells in the deep cortex, local activation of the renin-angiotensin system could cause acute papillary necrosis due to vasoconstriction.     

Haloalkylamine-induced renal papillary necrosis: a histopathological study of structure-activity relationships.

The haloalkylamine 2-bromoethanamine (BEA) causes necrosis of renal papillae of rats within 24 h of a single intraperitoneal dose greater than or equal to 100 mg/kg. Nine structural analogues of BEA, differing by halide substitution, alkyl chain elongation or amine substitution, were tested for their ability to induce renal papillary lesions in rats. Three compounds (2-chloroethanamine, 3-bromopropanamine and 2-chloro-N,N-dimethylethanamine) induced lesions which were morphologically indistinguishable from those of BEA. All the molecular structural variations investigated reduced papillotoxicity compared with BEA, the parent compound. A variety of non-renal lesions including hepatic, adrenal, testicular and lymphoid necroses were also encountered. The most toxic compound was 2-fluorethanamine, a 5 mg/kg dose of which was lethal and induced renal corticomedullary mineralization and centrilobular hepatic necrosis. One analogue, 3-bromo-2-hydroxypropanamine, caused rapid and extensive necrosis of the adrenal pars fasciculata and reticularis, simulating human Waterhouse Friderichsen syndrome. The three newly identified renal papillotoxins are all theoretically capable of generating direct-acting alkylating species in solution and their activity as direct-acting mutagens in the Ames bacterial mutagenicity test with TA100 (indicating base pair substitution) closely correlated with their potency as papillotoxins. We therefore hypothesize that non-enzymically formed direct-acting alkylating species mediate these papillary lesions, and that the target selectivity of haloalkylamine toxicity most probably results from the accumulation of these alkylating species in papillary tissue.     

Experimental renal papillary necrosis. Effects of beta adrenergic receptor blockade, heparin and hydrocortisone.

Renal papillary necrosis was induced in rats by daily subcutaneous injection of 15 mg 2-bromoethylamine hydrobromide (BEA) per 100 g of body weight for 2 successive days. This dose was 50% higher than that reported previously. Beta adrenergic receptor blockade with oxyprenolol did not influence the kidney damage.The administration of heparin did not show any effect. The doses applied did not induce the incoagulability for a sufficient period of time. On the contrary, treatment with hydrocortisone decreased papillary necrosis without inducing increased diuresis.     

Glomerular lesions in experimental renal papillary necrosis. I. Ultrastructural aspects and some pathogenic considerations.

Papillary necrosis was induced in rats by a single intravenous injection of bromoethylamine hydrobromide (BEA). From 7 days on glomerular lesions were recognized. They consisted of electron dense deposits mainly subepithelial in location; mild mesangial hypercellularity and matrix increase. Immunofluorescence with anti-rat gammaglobulin was positive, showing granular fluorescence in relation with basement membrane and mesangium. The possibility is raised that these lesions are due to the pathogenic action of immune complexes, the antigen being one arising during the necrosis of the renal papilla. It is also suggested that this mechanism can be operative in ths human being in cases of papillary necrosis of the kidney.     

Papillary necrosis in experimental renal transplantation in the rat

Renal papillary necrosis is a frequent complication of unsuccessful renal transplantation in rats, occurring in both isografts and allografts. Papillary necrosis does not occur alone, but only and inevitably in association with severe cortical damage. The pattern of the lesion is different from other forms of papillary necrosis in that the least severe lesions occur in the outer medulla and the more severe lesions involve both medulla and papilla. The incidence of papillary necrosis is increased in isografts, but not in allografts, by longer preservation times. It is suggested that the principal underlying cause may be damage to medullary capillaries, occurring either during preservation or as a consequence of rejection and leading to medullary ischemia.     

Experimental renal papillary necrosis in the rat: The selective vulnerability of medullary structures to injury

Summary Acute renal papillary necrosis was produced in rats by the administration of ethyleneimine. Low doses resulted in necrosis of interstitial cells, thin limbs of the loops of Henle and vasa recta, while collecting ducts were spared (subtotal renal papillary necrosis). High doses resulted in necrosis of all elements of the papilla (total renal papillary necrosis). Although the ranges of the doses that produced these two patterns of necrosis overlapped, it is clear that there is a dose dependent selective vulnerability of renal medullary structures to injury by the toxic agent studied.     

Natriuresis obtained by intracerebroventricular infusion of hypertonic NaCI in rats with papillary necrosis.

Raising the sodium concentration in the third cerebral ventricle increases renal sodium, potassium and water excretion. The identification and characterization of the factor(s) mediating the centrally evoked natriuresis would be greatly facilitated if the exact intrarenal effector site were known. We have assessed the importance of inner medullary structures for the effects of CNS stimulation by examining its ability to alter renal excretion in rats with papillary necrosis, induced 2 d earlier with 2-bromoethylamine hydrobromide (BEA), 250 mg kg^-1 body wt i. v. Male Lewis x DA rats were divided into a BEA-treated group (n = 6) and a control group receiving vehicle alone (n = 6). In contrast to the white papillae normally seen, the papillae of BEA-treated animals were bright red and showed a clear line of demarcation at their base. The rats were anaesthetized i. p. with Inactin (120 mg kg^-l body wt). Artificial cerebrospinal fluid (CSF) was infused (520 nL min^-1) via a cannula into the left lateral ventricle. After 45 min CSF containing 1 M NaCl was used. Stimulation of the control rats with hypertonic CSF increased urine flow rate five-fold (5.4± 0.8 to 27.1±6.1 μL min^-1), Na excretion 23-fold (0.4±0.1 to 7.6±1.8 μmol min^-1) and K excretion fourfold (0.6±0.18 to 3.8±O.5 pmol min^-1). When the concentration mechanisms were damaged with BEA, the basal excretion rates of water and Na increased. The natriuretic response to ICV stimulation was severely impaired in these rats, but the kaliuretic effect was sustained. In conclusion, the natriuretic effect of ICV stimulation with hypertonic CSF is dependent on an intact renal inner medulla, which is not the case for the less pronounced kaliuretic response. Thus, either the juxtamedullary nephrons possess marked natriuretic responsiveness, not present in the cortical ones, or the responsiveness lies mainly in the papillary collecting ducts. However, it cannot be excluded that a disturbance of salt balance contributes to the observations.     

Effect of papillary exposure on intrarenal distribution of glomerular filtration rate and of plasma flow

Removal of the renal pelvis in order to expose the renal papilla has been shown to cause impairment of the renal concentrating ability by an unknown mechanism. To study this phenomenon, urine osmolality (Uosm), single-nephron glomerular filtration rate (SNGFR) in outer and inner cortical nephrons and the inner and outer medullary plasma flow were determined. Measurements were performed on groups of rats before (control) and 15, 45 and 90 min after exposure of the left renal papilla. Rats with an intact ureter were studied in parallel to see whether the variables varied within the 90-min period of the study. In all groups of animals with an exposed papilla, Uosm was lower than in non-exposed animals. Outer cortical SNGFR in rats with exposed papillae, regardless of time, was not different from that in control rats. Inner cortical SNGFR after 45 and 90 min of exposure did not differ from that in controls, but after 15 min of exposure it was lower than in control animals. Outer and inner medullary plasma flow did not differ between rats with exposed papillae and controls, irrespective of exposure time. In conclusion, papillary exposure results in a permanent decrease in urine osmolality. This impairment of the concentrating ability cannot be attributed to prolonged changes in renal haemodynamics.     

Experimental Papillary Necrosis of the Kidney: III. Effects of Reserpine and Other Pharmacologic Agents on the Lesion

Reserpine is able to exert a pronounced inhibitory effect on the development of papillary necrosis following the administration of bromoethylamine hydrobromide to the rat. This inhibitory effect has been observed using light microscopy, histochemistry, indigo carmine excretion and urine output. These observations suggest that vasoconstriction may play a significant role in the pathogenesis of papillary necrosis, but the evidence for this is incomplete.     

Simultaneous medullary and papillary microcarcinoma of thyroid in a patient with secondary hyperparathyroidism

The simultaneous occurrence of two neoplasms of different cellular origin in one organ is a known but rare event. Such a situation occurs in the thyroid when medullary and follicular carcinoma with differentiation develops. Several cases of transitional tumors have been reported, but the simultaneous occurrence of a carcinoma with medullary and follicular differentiated carcinoma is rare. In all patients, tumors were suspected after local examination of the thyroid. We report on a patient in whom a papillary microcarcinoma was detected on the left side and a medullary carcinoma on the right side while the patient was undergoing surgery for secondary hyperparathyroidism. Both tumors were confirmed by immunohistology; regional lymph nodes were free of tumor. Although the simultaneous occurrence of papillary and medullary carcinoma may have been a simple coincidence, the patient’s history offers room for further speculation; he had chronic replicative hepatitis C and a 13-yr history of immunosuppression following renal transplantation. Therefore, a common oncogenic stimulus may have been involved. In the final analysis, the reason for both malignancies could not be clearly established.     

The time-course of changes in renal tissue composition during lysine vasopressin infusion in the rat

Summary The corticomedullary osmolal gradient, largely dissipated by sustained water-diuresis, was progressively repleted by continuous i.v. ADH infusion (lysine-vasopressin, 15 mU/min/100 g body weight) in conscious rats for up to 41/2 hr.A marked increase in sodium content was essentially complete by 1/2 hr in the papillary tip; smaller, but more progressive increases occurred in the papillary base and inner medulla. Increases in medullary urea content occurred mainly in the first 21/2 hr, especially in the papillary tip. A progressive decrease in water content of all medullary segments was preceded by a significant papillary tip increase at 1/2 hr.Papillary tip-urine osmotic equilibration was slowly achieved after about 21/2 hr. The small, but significant, tip-urinary urea concentration difference of water diuresis was more rapidly replaced by a substantial difference in the reverse direction.It is concluded that the changes can be explained, adequately, by ADH-induced modifications in water and urea permeabilities of distal nephron segments and, possibly, by changes in inner medullary blood flow; that the evidence of direct ADH stimulation of sodium transport is inconclusive; and that there was no evidence of active urea transport.     

Mixed medullary and follicular cell carcinoma of the thyroid with lymph node metastasis in a 7-year-old child

A 7-year-old boy presented with midline swelling in the neck. On fine-needle aspiration cytology it was diagnosed as papillary carcinoma of the thyroid. The patient underwent total thyroidectomy. Histopathological examination, immunohistochemistry and electron microscopy revealed the presence of two intermingled components: medullary carcinoma and papillary carcinoma. One of the submandibular lymph nodes had metastasis of both the components. The case was diagnosed as 'mixed medullary and follicular cell carcinoma' with papillary carcinoma pattern and lymph node metastasis. Mixed medullary and follicular cell carcinoma with intermingling of medullary and papillary carcinoma components is a rare tumor. In adults, only eight such cases with lymph node metastasis have been published. To the best of the authors' knowledge no pediatric case has previously been reported in the English-language literature.     

Renal vascular effects of frusemide in the rat: influence of salt loading and the role of angiotensin II

We showed recently that post-frusemide (furosemide) natriuresis was associated with a major depression of medullary circulation. In the present study, prior to administration of frusemide the tubular transport of NaCl was modified by loading the animals with 5% saline to elucidate a possible interrelation between the tubular and vascular effects of the drug. Moreover, a possible involvement of the renin-angiotensin system was examined by pharmacological blockade using captopril, an inhibitor of angiotensin converting enzyme (1 mg x kg(-1), I.V.), or losartan, a selective inhibitor of angiotensin AT1 receptor (10 mg x kg(-1), I.V.). The effects of frusemide (0.25 mg x kg(-1) I.V., then the same dose given over 1 h) on renal medullary and cortical circulation (using laser-Doppler flowmetry) and renal excretion of sodium (U(Na)V), water and total solutes were measured in anaesthetised rats. With no pre-treatment, frusemide decreased the medullary flow (36.6 +/- 6.0%) significantly more than the cortical flow (10.1 +/- 1.0%; P < 0.001). The difference between the medulla and cortex was not significant in rats which showed high U(Na)V after hypertonic saline loading (2.0 +/- 0.4 vs. 0.4 +/- 0.1 micromol x min(-1) in non-loaded rats): 21.1 +/- 3.9% and 15.8 +/- 1.5%, respectively. At very high U(Na)V (9.5 +/- 1.1 micromol x min(-1)) the post-frusemide decrease in blood flow tended to be smaller in the medulla (7.6 +/- 7.7%) than in the cortex (16.2 +/- 2.6%). The fall in medullary blood flow was attenuated by pre-treatment with captopril (22.0 +/- 3.3%) and abolished by pre-treatment with losartan (2.8 +/- 11.8%). The decrease in cortical blood flow was not changed by hypertonic saline or angiotensin II blockers. The abolition of the post-frusemide depression of medullary blood flow by previous salt loading confirms the proposed link between tubular transport status and vasoconstriction. A similar modification of the response by blockade of the renin-angiotensin system suggests that the system is involved in the mechanism of medullary vasoconstriction.     

Chronic renal lesions in the uninephrectomized Gunn rat after analgesic mixtures

Chronic cortical and medullary damage have been produced in uninephrectomized homozygous Gunn rats by single doses of the analgesics aspirin, paracetamol and phenazone, and by analgesic mixtures. The lesions are more severe than those of other experimental models of analgesic nephropathy, and the appearances of the cortical lesions suggest that they are ultimately due to the effects of papillary necrosis rather than to acute tubular necrosis observed in acute experiments with this model. The presence of an acute inflammatory reaction in both cortex and medulla in a number of animals one month after administration of analgesics indicates the possibility that the observed chronic renal damage may result from the intervention of additional complicating factors rather than from a single direct effect of analgesics.     

Experimental Papillary Necrosis of the Kidney: I. Morphologic and Functional Data

Papillary necrosis was produced in rats by a single intravenous injection of bromoethylamine hydrobromide (BEA). The earliest changes as seen by light microscopy were necroses of the limbs of Henle and eosinophilic droplets in collecting ducts. Complete necrosis of the papilla took place between 4 and 7 days and the dead papilla was usually sequestered completely by 21 days. Cortical changes occurred secondary to papillary necrosis. Tubular atrophy and loss was greatest in the deeper parts of the central cortex, the more superficial nephrons frequently being spared. The perihilar cortex was the least involved. This distribution was considered to be related to the respective lengths of the limbs of Henle, nephrons with limbs extending into the papilla being those undergoing change. Increased urine output occurred during the first day and continued thereafter. There was a profound defect in concentrating ability.     

Mechanisms of impaired urinary concentrating ability in adult rats treated neonatally with enalapril

Neonatal angiotensin-converting enzyme inhibition or angiotensin II type-1 receptor blockade induces irreversible renal histological abnormalities and an impaired urinary concentrating ability in the rat. The aim of the present study was to determine the pathophysiological mechanisms underlying the defect in urine concentration in adult rats treated neonatally with enalapril. Male Wistar rats received daily intraperitoneal injections of enalapril (10 mg kg(-1)) or saline vehicle from 3 to 24 days of age. Assessments of fluid handling and maximal urine osmolality (Uosm(max)), renal function and tubular free water reabsorption (T(c)H2O) under pentobarbital anaesthesia, renal tissue solute concentrations, renal aquaporin-2 (AQP2) expression, and kidney histology, were performed in 12-16-week-old rats. Uosm(max) (1488 +/- 109 vs. 2858 +/- 116 mosm kg(-1), P < 0.05) and maximal T(c)H2O were reduced in enalapril- vs. vehicle-treated rats after administration of 1-desamino-8-D-arginine vasopressin. Neonatally enalapril-treated rats showed marked papillary atrophy, a decrease in medullary tissue solute concentrations, and a reduction in AQP2 expression specifically in the inner medulla. Glomerular filtration rate, renal plasma flow and urinary excretion rates of sodium, potassium and chloride did not differ between groups. In conclusion, adult rats treated neonatally with enalapril showed a urinary concentrating defect of renal origin which primarily could be explained by the papillary atrophy. However, an impaired ability to generate medullary interstitial hypertonicity, and a decrease in inner medullary AQP2 expression, also seem to contribute to this defect.     

Asymmetrical atrophy of the renal medulla: a previously unreported abnormality

Investigation of the smaller of a pair of unequal kidneys showed a band of atrophy in the inner medulla, sparing the papillary tip, which was viable and contained collecting ducts. The kidney had extensive cortical atrophy with glomerulocystic disease and multiple tiny renal cell neoplasms. These changes were considered secondary to the medullary lesion. Study of 85 other kidneys taken at autopsy and surgery showed 8 other cases with similar band-like atrophy in the medulla to various degrees. All 9 cases had severe vascular disease. This asymmetrical or band-like atrophy of the renal medulla seemed to be fairly common but previously unreported, could be differentiated from renal papillary necrosis, and was most likely due to an episode of severe ischaemia, possibly in kidneys with pre-existing vascular narrowing.     

Expression of Jun activation domain-binding protein 1 and p27 (Kip1) in thyroid medullary carcinoma

AIMS: p27 is a prominent regulator of cell proliferation by universally inhibiting the cell cycle, while Jun activation domain-binding protein 1 (Jab1), a multifunctional cell signaling protein, contributes to carcinoma progression by degrading p27. In this study, we investigated the expression of these proteins in medullary thyroid carcinoma. METHODS: We immunohistochemically examined Jab1 and p27 expression in 64 medullary thyroid carcinomas. RESULTS: Of the 64 cases examined, decreased p27 expression was observed in 38 cases (59.4%). The p27 expression level was inversely linked to tumour size as well as plasma calcitonin level. Jab1 expression level was generally high, and 46 cases (71.9%) were classified as overexpressing Jab1. The incidence was higher than those in papillary and follicular carcinomas, which were previously reported. Jab1 expression level was inversely linked to that of p27, and all five cases with only cytoplasmic but not nuclear staining of p27 overexpressed Jab1. CONCLUSIONS: These findings suggest that (1) decrease in p27 expression may contribute to local tumour growth; (2) Jab1 expression is related to the progression of medullary carcinoma by decreasing the amount of p27 in the cell and accelerating its degradation; and (3) Jab1 may play a more vital role in the pathogenesis of medullary carcinoma than papillary and follicular carcinomas.