Relationship between renin and intrarenal hemodynamics in hemorrhagic hypotension.

In order to investigate the possible role of the renin-angiotensin system in the regulation of intrarenal hemodynamics in hemorrhagic hypotension (HH), seven mongrel dogs have been studied under the following conditions: (a) Control, (b) HH (mean arterial pressure 70 mm Hg), and (c) HH + alpha adrenergic blockade by phenoxybenzamine (HH + POB). The following parameters were obtained for the right kidney: Intrarenal distribution of blood flow and local blood flow rates ((133)Xe washout technique); total renal blood flow (RBF) on the basis of the clearance and extraction ratio of PAH and the arterial hematocrit; plasma renin concentrations in the renal artery and vein by the method of Boucher and his associates; and renin release into the renal circulation. Alpha adrenergic blockade reverted the typical redistribution of intrarenal blood flow observed under HH. In hemorrhage, arterial and venous renin concentrations increased by a factor of 3.4 and 4.8 respectively. A further small increase was observed during HH + POB with the respective factors increasing to 4.8 and 5.3, as compared with control values. The renin release into the circulation increased by a factor of 1.2 in HH and 4.0 in HH + POB. Whereas in HH there seemed to be a relationship between increased renin concentrations or renin release, and the redistribution of blood flow, no such correlation was found during alpha-adrenergic blockade. From these observations it is concluded that renin alone is unable to maintain the typical redistribution of RBF seen during hemorrhage. Circumstantial evidence points to a permissive role of the renin-angiotensin system in the pathogenesis of the patchy cortical hypoperfusion caused by sympathoadrenergic mechanisms during hemorrhagic hypotension.

Intrarenal distribution of blood flow in the transplanted dog kidney: effect of denervation and rejection.

Serial measurements of intrarenal distribution of blood flow have been recorded in anesthetized dogs with the (133)xenon "washout" technique. The results showed that normal kidneys redistributed their blood flow after laparotomy and mobilization of the kidney. This alteration consisted of a diminution in percentage of total renal blood flow supplied to the fastest flowing component, and a diminution of renal mass supplied by that component. This effect lasted for as long as 7 days. Thereafter, the blood flow distribution remained stable. Autotransplanted kidneys had a stable distribution of blood flow between 0 and 77 days after operation, the values being identical with the stable normal kidney. Homotransplanted kidneys had the same intrarenal distribution of blood flow after operation as the autotransplanted kidneys. Whereas the intrarenal distribution of blood flow of the autotransplanted kidneys remained stable, a redistribution occurred in the homotransplanted kidneys as rejection progressed. This phenomenon occurred before marked elevation of blood urea nitrogen. The redistribution was due to a decrease in percentage of blood flow supplied to the fastest flowing component, and a relative reduction of tissue mass perfused by this component. Radioautography of the kidneys before rejection demonstrated that the cortex was homogeneously perfused by the fastest flowing component of blood flow. As rejection progressed, a reduced area of cortex was perfused by this component. Terminally, the fastest flowing component was located in the outer medulla. It is suggested that the reduction in cortical blood flow produced by immunological mechanisms may play a prominent role in the ensuing renal failure.

Redistribution of Renal Blood Flow in Haemorrhagic Hypotension Role of Renal Nerves and Circulating Catecholamines* *.

Haemorrhagic hypotension (HH) causes a redistribution of intrarenal blood flow characterized by a patchy cortical hypoperfusion. Previous studies indicated that the sYmpathoadrenergic system is mainly responsible for these redistribution processes. The relative role of renal nerves and of circulating catecholamines was studied in the present experiments. Intrarenal haemodynamics were analysed by means of the 133 Xenon washout technique and 83 Krypton autoradiographics. 8 autotransplanted (and, therefore, chronically denervated) kidneys showed the same typical response to severe and prolonged HH as 11 normal control organs. In 2 additional dogs, the intrarenal distribution of blood flow (IDBF) and local blood flow rates (Fi ) of an acutely denervated kidney before and during HH did not show any differences as compared with the contralateral control organ. It is concluded that the patchy cortical hypoperfusion observed in the dog during severe haemorrhagic hypotension does not depend on an intact innervation of the kidney, but that it is mainly mediated by circulating catecholamines.

Immunothrombocytopenia and IgA nephritis.

A 32 year old female patient demonstrates the rare combination of a typical IgA nephritis and familial immunothrombocytopenia. Although this association may be purely fortuitous, our observation adds a new facet to a spectrum of reports on (familial) "thromborenal syndromes". The pathogenesis of the IgA nephritis has not yet been clarified. However, since IgA deposits are found relatively frequently in the mesangium in a number of diverse underlying diseases, there might be common etiological factors. In view of this possibility more attention should be directed to the investigation of IgA associated diseases.

[Emergency stiuations connected with electrolyte disorders. Special aspects]. / Situazioni d'urgenza collegate con disordini elettrolitici. Aspetti particolari

Electrolyte-induced situations which are dangerous to life usually result from disturbances of the extracellular volume (ECV), osmolarity, the potassium level or the acid-base equilibrium. In recent years (thanks to the wide spread use of hormone therapy for mammary carcinoma) severe hypercalcemia has increased in importance as a life-threatening complication, while hypocalcemia, at least in adults, should only very seldom lead to unexpected emergencies. As long as serious clinical symptoms do not suggest an emergency, assessment of the threat to the patient as a result of the existing electrolyte disturbance often causes some difficulty. Besides the extent of the deviation from normal, the rate of development of the disturbance determines the resulting danger: chronic hypo-osmolarity, and especially hyperosmolarity are occasionally tolerated without symptoms while acute disturbances of the same or a less extent lead to severe central nervous symptoms. A similar state of affairs is also true of the emergency situations arising from disturbances of the acid-base equilibrium, among which the respiratory disorders are particularly important clinically. In the case of threatening disorders of the potassium metabolism, the accompanying circumstances (digitalis, simultaneous disorders and treatment of the acid-base equilibrium) often determine the clinical significance and danger to the patient. Clinical symptoms, anticipation ("expecting the unexpected"), prevention and treatment of emergency situations of fluid volume, osmolarity, potassium and acid-base equilibrium are the subjects of this paper.

[Microhematuria of renal origin--differential diagnosis, clarification and interpretation]. / Mikrohämaturien renaler Genese--Differentialdiagnose, Abklärung und Interpretation.

Microhematuria offers a wide spectrum of diagnostic possibilities. Once the finding is confirmed, the diagnosis of prerenal, renal-parenchymatous and postrenal (or even factitious) hematuria and differentiation between glomerular and nonglomerular bleeding sources is based on the patient's history, a complete clinical status, special urinary findings (mainly red cell casts, proteinuria and red cell morphology) and blood chemistry (serum creatinine or creatinine clearance). If on the basis of this information glomerular or renal-parenchymatous microhematuria seems likely, further diagnostic procedures include immunological tests and, if indicated and justified, renal biopsy. Urography and other imaging procedures, urinary cytology and cystoscopy (firmly indicated when doubts persist or all the evidence points to postrenal hematuria) are deferred whenever glomerular hematuria seems likely. The special aspects of isolated renal microhematuria are discussed.

[Myasthenia gravis and visceral lupus erythematosus]. / Myasthenia gravis und viszeraler Lupus erythematodes.

The patient described in this clinical demonstration suffered from severe myasthenia gravis shortly before the detection and for 3 years after surgical removal of a cystic thymoma. At the end of this period, when the myasthenia subsided, she developed systemic lupus erythematosus simultaneously with pleural implantation metastases of the thymoma. After local radiation therapy and under systemic immunosuppression she has remained asymptomatic since the spring of 1978. The pathogenetic and immunogenetic basis of myasthenia gravis and autoimmune diseases associated with thymoma and thymus hyperplasia is reviewed, and a plea is entered for more comprehensive and integrative internal medicine.

[Electrolyte Emergencies. Selected Aspects]. / Elektrolytbedingte Notallsituationen. Ausgewählte Aspekte

The question of what factors determine the significance of abnormal electrolyte findings is discussed with reference to a number of examples of acute electrolyte emergencies (hyponatremia, hypernatremia, hypokalemia, hyperkalemia, metabolic alkalosis). In addition to the extent of the deviation from normal and the clinical manifestations already present in all cases, it is principally the rate of dysfunction which determines the action of a clinical or laboratory-determined electrolyte deviation.

[Water intoxication]. / Wasserintoxikation

In uncharacteristic clinical symptomatology the excess of water or the water intoxication render themselves conspicuous less by the signs of an increased fluid content than by central-nervous disturbances. Among the results of laboratory examinations the hypoosmolarity measured cryoscopically always, the hyponatraemia in most cases prove the excess of free water. Exceptions are discussed. A decreased capacity of the elimination of water pathogenetically plays a larger role than primarily excessive water supply. Apart from acute and chronic renal insufficiency the various forms of the Schwartz-Bartter-syndrome (inadequate ADH-secretion) play an increasingly more important role. The therapy demands the reduction of every supply of free water, the treatment of the evoking cause and only in cases of exception the administration of hypertonic saline solution, at the most dialysis treatment.