A light and electron microscopic study of HLA-DR positive cells in the human cerebral cortex and subcortical white matter

Specimens of histologically normal human cerebral cortex and subcortical white matter were obtained during neurosurgical operations and studied by electron microscopy and immunocytochemistry using an antibody against HLA-DR. Greater numbers of labelled cells were present in the white matter than in the overlying cortex. The labelled cells consisted of ramified microglia and perivascular cells. Microglia were often found just outside the walls of small blood vessels, but perivascular cells were actually enclosed by two leaflets of basement membrane in the walls of capillaries, arterioles and venules up to 100 microns in luminal diameter. Labelled microglial processes were often seen enclosing neuronal processes in the cortex and myelinated and unmyelinated axons in the white matter. The enclosed processes appeared healthy, and without features of degenerating neurons. These observations are consistent with a previous suggestion that microglia continually modify the processes of central nervous system neurons by a process of phagocytosis. An intact blood-brain barrier is likely to be of great importance in preventing antigen presentation of the processed neuronal, and perhaps even oligodendrocytic, antigenic peptide fragments to circulating lymphocytes.     

Effects of the enediyne C-1027 on intracellular DNA targets

We examined DNA damage induced by the enediyne-containing antitumor antibiotic C-1027 in intracellular nuclear and mitochondrial DNA targets using the episome-containing cell line 935.1. Strand-scission activity of the C-1027 holoantibiotic was measured by the topological forms conversion assay in episomal and mitochondrial DNA, as well as in cell-free plasmid DNA. Genomic DNA damage was quantitated by filter elution analysis. Comparisons were made to the well-characterized enediyne neocarzinostatin. From these studies, mixed single- and double-strand breaks were observed not only in cell-free, plasmid DNA but also in intracellular episomal, mitochondrial, and genomic DNA at low nanomolar concentrations. C-1027 cleaved DNA 285-fold more efficiently in cells than in a cell-free environment, and displayed preference for intracellular DNA species in the following rank order: episome > mitochondrial DNA > genomic. NCS also damaged the non-histone-associated mitochondrial DNA, but not the episome. Cleavage of the 935.1 cell episome by C-1027 occurred at specific sites including the BPV origin of replication and E6/E7 open reading frame regions, as well as the MMTV LTR promoter region.     

Proliferative glomerulonephritis in monoclonal gammopathy

A 62-year-old white male suffering from plasmacytosis with monoclonal gammopathy developed gastrointestinal bleeding, microscopic hematuria, proteinuria and progressive azotemia. A renal biopsy demonstrated capillary wall thickening, mesangial hyperplasia, crescent formation and subepithelial humps. Serum immunoglobulin analysis showed IgG of lambda type. Serum complement, ANA, ASO titer and cryoglobulin were normal. It is suggested that proliferative glomerulonephritis with subepithelial humps should be added to forms of renal pathology that can be seen in plasma cell dyscrasias.     

Coronary obstruction secondary to direct cannulation

Four patients are reported with obstruction of the proximal left main coronary artery that developed following prosthetic replacement of the aortic valve. Angina pectoris and ventricular arrhythmias were the presenting clinical manifestations. Anterior descending coronary artery bypass was used in 3 of the patients and vein patch angioplasty in the fourth. One patient died in the hospital. The 3 survivors achieved reflief from angina and ventricular arrhythmias. One patient died from nephropathy 2 1/2 years later. Two patients remained asymptomatic 1 1/2 and 3 years later, respectively. This review emphasizes the need for prompt coronary angiography in patients experiencing angina pectoris after aortic valve replacement, and it shows that coronary revascularization can be performed with satisfactory results.     

Fate and efficiency of nitrogen fertilizers applied to wetland rice. I. The Philippines

Urea is the main form of fertilizer nitrogen applied to wetland rice. As part of an effort to evaluate the efficiency of nitrogen fertilizers, conventional urea and modified urea products such as sulfur-coated urea (SCU), urea supergranules (USG), and sulfur-coated urea supergranules (SCUSG) were compared with ammonium sulfate on an Aquic Tropudalf at the experimental farm of the International Rice Research Institute (IRRI) in the Philippines. The sulfur-coated materials were prepared in the laboratory and were not completely representative of commercial SCU. Two experiments were conducted in the wet season (1978, 1979) and one in the dry season (1979). All fertilizers were labeled with 5% or 10% excess¹⁵N so that the fertilizer-N balance at two or three sampling times during the growing season could be constructed and the magnitude of N loss assessed. The SCU, USG, and SCUSG were applied at transplanting, and the whole dose of nitrogen was¹⁵N-labeled. The urea and ammonium sulfate applications were split: two-thirds was broadcast and incorporated at transplanting, and one-third was broadcast at panicle initiation; only the initial dose was¹⁵N-labeled.Deep-point placement (10 cm) of urea supergranules (USG) between the rice hills consistently provided the highest plant recovery of¹⁵N in all experiments and at all harvest times; recoveries ranged from 48% to 75% with an average of approximately 58% at maturity. Among the fertilizers broadcast and incorporated before transplanting, average plant recoveries of¹⁵N were only approximately 34% and 26% from urea and ammonium sulfate, respectively. Plant recovery of¹⁵N from the broadcast and incorporated SCU (37%) was far inferior to that from USG. Sulfur coating of supergranules did not improve plant recovery over USG alone although sulfur coating delayed the plant uptake of¹⁵N from the USG.The¹⁵N not accounted for in the plant and soil was presumed lost. Loss of N from urea and ammonium sulfate was high (63%) in the dry season. Coating with sulfur gave a slight improvement, and deep placement of USG and SCUSG greatly reduced the losses. Losses of N were substantially lower in the wet season than in the dry season for broadcast and incorporated urea, SCU, and ammonium sulfate (9%–30%), whereas losses from deep-placed urea remained more or less the same as in the dry season. Net immobilization of¹⁵N from the broadcast fertilizers in the wet season ranged from 49% to 53% in the first experiment and from 16% to 32% in the second experiment, presumably because of aquatic weeds and green algae; immobilization was proportionally less at higher rates of fertilizer application. Deep placement reduced the extent of¹⁵N immobilization in the soil plus roots to less than 21% in all experiments.     

Inhibition of acoustic priming in mice

Mice of the C57BL/6J strain can be made susceptible to audiogenic seizures by a process known as acoustic priming. Acoustic priming can be blocked when the animals are injected either with puromycin or with puromycin aminonucleoside before the application of the priming stimulus. Cycloheximide, diphenylhydantoin, and d-amphetamine had little effect on priming-induced audiogenic seizures in these animals. All of these drugs, however, when given in combination with puromycin reversed in the protective action of puromycin against audiogenic seizures. Puromycin administered to 19-day-old mice increased susceptibility to electroconvulsive seizures when the animals were tested at 22 days of age. It is suggested that puromycin is able to block priming-induced audiogenic seizures by producing abnormal electrical activity in the brain or through an interference with normal neurohumoral transmission by incomplete peptides.     

Centrally mediated hypocholesterolaemic response of insulin in dogs

Insulin on intravenous administration in dogs caused a rise in blood cholesterol level. This may be due to its direct action on liver or other peripheral structures. On the other hand, insulin administered into the lateral cerebral ventricles in normal as well as in spinal and vagotomized dogs resulted in a lowering of blood cholesterol. In cross circulation studies insulin administered into lateral cerebral ventricles of donor dogs produced a hypocholesterolaemia in the recepient dogs without significant changes in blood cholesterol of donor dogs. It is suggested that some substance may be liberated from some parts of central nervous system due to an action of centrally administered insulin. This substance in turn causes hypocholesterolaemia by acting on liver or some other peripheral structures in dogs.     

Unusual manifestations of Henoch-Sch?nlein syndrome

Henoch-Sch?nlein syndrome represents a diagnostic challenge when the abdominal and/or joint manifestations precede the cutaneous lesions. Laparotomy is often performed unnecessarily. We describe a patient whose abdominal symptoms antedated the appearance of cutaneous lesions by three months. Gastrointestinal blood loss, thrombocytosis, hypoproteinemia, and the roentgenographic appearance of the small intestine suggested the correct diagnosis. His course was further complicated by hypertension associated with elevated plasma renin levels without evidence of nephritis. Joint manifestations were mild and transient as were testicular pain and swelling.