Purification of angiogenin from cow''s milk

The crystal structure of Arthromyces ramosus peroxidase (ARP) in complex with benzhydroxamic acid (BHA) as determined by X-ray analysis at 1.6 A shows unambiguously how BHA binds to ARP. BHA is located in the distal heme pocket. Its functional groups are held by three hydrogen bonds to His56N(epsilon), Arg52N(epsilon), and Pro(154)O, but are too far away to interact with the heme iron. The aromatic ring of BHA is positioned at the entrance of the channel to the heme pocket, approximately parallel to the heme group. Most water molecules at the active site of the native enzyme are replaced by BHA, leaving a ligand, probably a water molecule, at the sixth position of the heme. Results are compared with spectroscopic data.     

Pathomorphology of the kidneys in hemolytic-uremic syndrome in children

The kidneys were studied morphologically in 64 cases of hemolytic-uremic syndrome (HUS) in children aged from 17 days to 4 years. Three variants of the kidney alterations are distinguished depending on the duration of acute renal failure (ARF): early, late and delayed alterations. Early alterations were observed if ARF lasted for 1-10 days and were characterized by glomerular thrombotic microangiopathy with disturbance of the nephron proximal part function resultant from microcirculatory damage. Late kidney alterations (11-20 days of ARF) consisted of glomerular thrombi fibrinolysis, development of mesangial cell proliferation and mesangiolysis, proximal tubular epithelium regeneration and the appearance of nephrohydrosis resulting from the distal nephron part obstruction by hyalin cylinders. Delayed alterations (21-62 days of ARF) manifested with predominant atrophic and sclerotic processes. The first variant corresponded to the acute course of HUS while the two last variants to the subacute one.     

Helicobacter pylori and stomach cancer]

The neoplasms and gastric mucosa colonization with Helicobacter pylori was studied in 40 stomachs resected for expansive (n = 20) and infiltrative (n = 20) carcinoma using Giemsa staining histological sections, histochemical reactions to oxyreductase, and urease test. In expansive carcinoma of the stomach, H. pylori was identifiable both in the tumour and surrounding gastric mucosa in 70 per cent of cases; infiltrative carcinoma appeared to be associated with gastric mucosa H. pylori in 80 per cent, whereas tumour H. pylori were recordable in 30 per cent of cases, which fact is dependent upon the histological structure of carcinoma. The role H. pylori plays in cancerogenesis is discussed.     

Histogenesis and diagnostic of kidney cancer in the light of electron microscopic data

Electron microscopic examinations of human renal carcinoma showed that both light and dark (granular) differentiated tumour cells may have ultrastructural features of the cells of any nephron segment. In the light of these results and concepts of the capacity of undifferentiated tumour cells for specific differentiation, the decisive importance in histogenesis (cytogenesis) of the renal carcinoma belongs not to the site of its origin in one or another nephron segment but to the level of differentiation of stem cells (polypotent or monopotent) undergoing malignization and to the direction of their further differentiation. The paper presents concrete ultrastructural differential diagnostic features of renal carcinoma cells.     

Presence of cross-reacting thymus and brain antigens in the cerebral cortex

Rabbit antisera against antigens of mouse, rabbit, guinea pig and human whole brain cross-reacted in the cytotoxic test with the lymphocytes of the thymus, lymph nodes and the spleen of these animal species. Mouse thymocytes were most sensitive to the antibrain sera (cytotoxic index -- 63--100 per cent); cells from other mouse lymphoid organs and lymphocytes of rabbit, guinea pig and man were more resistant. Bone marrow lymphocytes were not damaged by any of these sera. The antigens which induced the cytotoxic properties of the sera were found only in the human cerebral cortex, but not in the white matter of the brain stem.     

Electron-microscopic radioautography of DNA-synthesizing cells of growing rat smooth muscle tissue

DNA-synthesizing cells of rat stomach muscle tissue following 50% resection of the fundal part, identical cells of the vena cava after disturbance of the blood out flow, and of the appendix on contraction of the ascending part of the large intestine were studied by electron microscopic autoradiography. DNA synthesis in the differentiated myocyte nuclei of the stomach muscle tissue, and of the "activated" myocytes of the stomach and the vein was observed. There were signs of asynchronous DNA synthesis in the nuclei of some smooth muscle cells and fibroblasts.