Summary. The ultrastructure of the pancreatic islets was studied in seven surgical specimens of human pancreas. The effects of two different fixation methods were compared: osmium tetroxide alone and glutaraldehyde followed by osmium. On the basis of their ultrastructural characteristics, four main types of islet cells were identified: 1. B cells, with polymorphous, often crystalline granules contained in wide sacs. 2. A cells with rounded granules enclosed in tight fitting sacs and composed of an electron-dense core surrounded by a clearer halo. 3. Type III cells, with rounded, large homogeneous granules of varying sizes and electron densities. They presumably secrete gastrin. Comparable cells were found in samples of human gastric and duodenal mucosae. 4. Type IV cells, with rounded, small, homogeneous granules of low electron density. Comparable cells were found in human gastrie and duodenal mucosae. The nature of their secretion remains obscure. A fifth cell type was observed in the pancreas but was not restricted to the islets. Ceils of type V have small, polymorphous and very electron-dense granules. They offer a certain resemblance with the serotonin secreting cells which are found in the digestive tract. L'ultrastructure des ~tots de Langerhans de pancrgas humains. I. Lee ~lots des aduttesRdsumd. L'ultrastrueture des riots de Langerhans a 6t6 6tudi6e sur des pr616vements chirurgicaux de sept pancr6as humains. Les effets de la fixation par le t6troxyde d'osmium seulet par la glutarald6hyde suivie d'osmium ont 6t6 eompar6s. Quatre types eellulaires ont pu 6tre identifi6s: 1. Cellules B, ~ granulation polymorphe, de structure fr6quemment eristalline, incluses dans de larges v6sieules. 2. Cellules A k granules arrondis, eompos6s d'un noyau dense entour6 par un halo clair et inelus ~ l'6troit dans une enveloppe membranaire. 3. Cellules du type III grosses granulations arrondies, de structure homog6ne, de densit6 et de forme variables. Ces cellules s6cr6tent peut-6tre de la gastrine. Des 616ments similaires ont 6t6 rencontr6s dans les muqueuses gastrique et duod6nale. 4. Cellules du type IV, k petites granulations homog6nes et p&les. Des 616ments similaires ont 6t6 aper~us dans les muqueuses gastrique et duod6nale; leur fonetion reste inconnue. Des eellules d'un einqui6me type se voient dans le paner6as, m~me en dehors des ilots. Elles sont caract6-ris6es par de petits granules, tr6s denses et polymorphes: elles offrent une eertaine ressemblance avec les cellules s6rotonine que l'on trouve dans le tube digestif. Die Ultrastruletur der Inseln des menschlichen Pankreas. I. Die Inseln yon ErwachsenenZusamrnenfassung. Die Ultrastruktur der Langerhansschen Inseln wurde an Hand yon chirurgischen Probeexzisionen an 7 menschliehen Pankreata studiert. Die Ergebnisse der Fixierung durch Osmium-Tetraoxyd einerseits und dureh Glutaraldehyd gefolgt yon Osmium anderseits wurden vergliehen. So konnten vier Zelltypen identifiziert werden: 1. B-Zellen mit polymorphen, und oft kristallinen Granulationen, die in breiten S/~ekche...

1. Plasma renin concentrations were determined in 1068 samples obtained in 113 patients in the end stage of chronic renal failure treated by repeated haemodialyses or by renal transplantation. 2. Patients with malignant nephroangiosclerosis have a very high concentration of plasma renin; this differentiates them from other disease groups, where renin concentration is sometimes normal and sometimes elevated; there is no significant difference between the glomerulonephritis and pyelonephritis groups. 3. There is a weak but significant correlation between plasma renin concentration and arterial blood pressure. In the terminal stage of chronic renal insufficiency, blood pressure appears to be controlled by other quantitatively more important factors. However, the hypertension of some cases, characterized by high concentrations of plasma renin, can be controlled only by bilateral nephrectomy. 4. There is an inverse and highly significant correlation between plasma renin and sodium concentrations. This is also the case in transplanted patients where an inverse correlation also exists between plasma renin concentration and daily urinary output of sodium. 5. The juxtaglomerular granulation index correlates positively with the plasma renin concentration. 6. In terminal renal failure the kidney retains its capacity to secrete renin as a response to acute haemorrhage or other stimuli. 7. Renin is present in the blood of anephric patients and its concentration is not correlated either with the patient's sex or with the time elapsed after binephrectomy. 8. During rejection episodes in transplanted patients a rise of plasma renin concentration is frequently but not invariably observed. Elevation of plasma renin concentration is evident in very acute rejection crises.

SUMMARY The distribution of amyloid in various organs, including the hip and the sternoclavicular joints, was systematically investigated in a prospective necropsy study of 91 unselected individuals whose median age was 70 years. The overall incidence of amyloid microdeposits in both joints was 56%. Their presence correlated significantly with age only. The deposition began earlier in the sternoclavicular joint, where the fibrocartilaginous disc was almost exclusively affected. The myocardium was the next most frequently affected organ, with an incidence of 12.2%. Minor amyloidosis of the articular tissues had no significant clinical counterpart, neither was it associated with any particular disease. It seemingly represents a localised and isolated degenerative phenomenon, whose morphological aspects invite speculation about the pathogenic role of long-lasting mechanical stress.

The ultrastructure of the islets of Langerhans was studied in seven human neonates. Out of the five cell types, described by the same authors in the islets of adults, four were also found in the islets of neonates: B cells, A cells, type III ceils and type IV cells. Type III cells were far more numerous in the newborn in contrast with type V cells which were not found. In comparison with the islets of adults those of neonates showed a considerably higher number of pale granules in the B cells and a complete absence of fat vacuoles in all four cell types. L'ultrastrueture des ~[ots de Langerhans de pancrgas humains. I I. Les ~lots de nouveau-ntis YRdsumg. L'ultrastructure des riots de Langerhans a 6t6 6tudi6e sur sept pancr6as de nouveau-n6s. Quatre des einq types eellulaires que les auteurs ont d6erits dans les riots d'adultes ont 6t6 retrouv6s ehez le nouveau-n6: eellules B, cellules A, eellules du type III et eellules du type IV. Les eellules du type V font d6faut ehez le nouveau-n6 qui, par centre pr6sente une plus grande abondance de cellules du type III. D'autres diff6rences notables avec l'adulte sont prdsentes ehez le nouveau-n6: une proportion nettement plus grande de grains pales dans les cellules B et l'absence de vacuoles graisseuses dans les eellules insulaires de tous types. Die Ultrastruktur der Inse[n des menschlichen Panlcreas. I I. Die Inseln yon Neugeborenen Zusammenfassung. Die Ultrastruktur der Langerhans'schen Inseln wurde in den Pankreata yon 7 Neugeborenen untersueht. Vier der fiinf Zelltypen, welehe die Autoren in des Inseln Erwaehsener besehrieben hatten, konnten auch beim Neugeborenen gefunden werden: B-Zellen, A-Zellen, Typ III-und Typ IV-Zellen. Die Typ V-Zellen fehlen beim Neugeborenen. Dieser hat dagegen mehr Zellea veto Typ III. Noeh andere wiehtige Unterschiede lassen sieh beim Neugeborenen finden: eine deutlich gr613ere Menge blasser Granula in den B-Zellen, sowie das v611ige Fehlen yon Fett-Vaeuolen in den Inselzellen aller Typen.