Per M. Lundin

Ultrastructure of mucosal mast cells in normal and compound 48/80-treated rats

SummaryMast cells in the tongue and lamina propria of the duodenal mucosa, representing two cell types with different morphological, histochemical and functional properties have been studied under the electron microscope. Both cell types were found to contain similar moderately electron dense and homogeneous granules surrounded by a tight membrane constituting the basic ultrastructural characteristics of mast cells. The mucosal mast cells, however, contained fewer granules per cell and the individual granules often exhibited considerable variation in size. In addition the mucosal mast cells, unlike those of the tongue, peritoneum and skin, had a smooth plasma membrane lacking microvilli and possessed irregularly shaped or lobulated nuclei. In the tongue mast cells, administration of Compound 48/80 caused the formation of vacuoles around the granules, expulsion of granules from the cells and disintegration of the granular matrix, but no changes that could be attributed to 48/80 could be found in the mucosal mast cells.

Polycystic Kidneys in Newborns, Infants and Children A Clinical and Pathological Study

Twenty‐eight cases of polycystic kidneys in newborn, infants and children have been investigated clinically and histopathologically. Three more or less distinct morphological types of polycystic kidneys are described and in addition single cases of deviating appearance. The clinical and hereditary aspects are discussed. In Group I (spongy kidney) a single gene recessive heredity has been proved.

On the single cell state in enzymatically produced tumor cell suspensions

Abstract In enzymatically produced suspensions of mouse sarcoma cells a DNasesensitive extra cellular gel, probably DNP, appears, entrapping cells. To prevent such clumping adequate amounts of DNase are needed, occasionally several times the concentrations recommended for enzymatic techniques. The amount of DNase required probably varies from tumor to tumor. In addition an instant spontaneous primary aggregation of cells is recorded when tumor cells are suspended in chemically defined media. Aggregation does not appear in balanced salt solutions, probably a devitalization phenomenon. Aggregation can, however, be inhibited and already formed aggregates can be dissociated by the presence of serum or cell-free ascitic fluid. It is recommended that these factors should be checked when strictly single cell suspensions of tumor cells are required.

The fate of iron-sorbitol in rat striated muscle

Electron microscopic investigations of synthetic and naturally occurring iron compounds have given us much information regarding normal and pathological iron metabolism and about some cellular phenomena during the intracellular transformation of complex iron compounds. The transformation of iron-dextran to ferritin, for example, has been thoroughly studied (RICHTER 1959, WESSEL and GEDIGK 1959, MUIR and GOLBERG 1961). Iron-dextran is clearly visible in the electron microscope, and at moderate magnification intracellular digestion of sidcrosomes can be folh)wcd in detail. Iron-sorbitol 1, a new compound for parcnteral iron therapy, is a colloidal solution of iron prepared in the presence of sorbitol, citric acid and dextrin. The final solution contains 50 mg iron/ml and its pH is 7.5. The iron compound is not chemically uniform, nor does it have a well-defined molecular weight. Ultracentrifugation of the polydispersed iron compound gives an upper limit of the sedimentation constant of 8--9 Swedberg units. On certain assumptions the average molecular weight can be estimated to be below 5000. Electrophorctic investigations at pH 7.6 have proved that the compound contains at least two high molecular iron components which migrate towards the anode. About 6 per cent occurs as a more rapidly moving and dialyzable form. Dextrin can be separated from the iron-containing fractions and the dextrin presumably acts as a protective colloid (LINDVALL and ANDERSSON 1961). Intramuscularly injected iron-sorbitol is very rapidly removed from the injection site in man and experimental animals, and after 3 hours about two-thirds of the iron has vanished. After 12 hours about 17 per cent remains at the injection site. The residue disappears very slowly, and after 32 days about 6 per cent of the iron is still left at the injection site (I,INDVALL and ANDERSSON 1961). Besides the chemical composition, iron-sorbitol differs from iron-dextran essentially in molecular size, which mainly determines the rate of absorption from the injection site. The aim of the present investigation was to study, in the electron microscope, the fate of iron-sorbitol-citrate intramuscularly injected in rats.