Receptor-mediated uptake and 'retroendocytosis' of high-density lipoproteins by cholesterol-loaded human monocyte-derived macrophages: possible role in enhancing reverse cholesterol transport

Human monocyte-derived macrophages (MDM) are cholesterol-loaded, and the rates of uptake, degradation and resecretion of high-density lipoproteins are measured and compared to the rates in control cells. Results show the binding activity of these lipoproteins is upregulated in cholesterol-loaded cells; the bound and internalized lipoproteins are not degraded to any appreciable extent but primarily resecreted as a larger particle. The enhancement of binding activity for high-density lipoproteins is arrested when cycloheximide is added to the medium, suggesting that protein synthesis is involved. Preliminary evidence also indicates that HDL3 (without apoE) after internalisation is converted intracellularly to a larger apoE-containing HDL2-like particles. Thus, MDM appears to possess specific receptors for HDL3 without apoE that may function to facilitate HDL-mediated removal of excess cholesterol from cells.

Kidney-preserving radical tumor resection in advanced neuroblastoma

The possibility of kidney-preserving radical tumor resection in advanced neuroblastoma was evaluated. Eighteen patients with stage III and IV adrenal neuroblastoma underwent delayed primary surgery after chemotherapy consisting of high doses of cyclophosphamide (1,250 mg/m2). Radical tumor resection with nephrectomy was performed in 13 patients (group A) and kidney-preserving radical tumor resection was performed in six patients (group B). Macroscopic findings were evaluated in all patients; angiographic and microscopic findings were evaluated in group A patients and tumor recurrence in group B patients. Macroscopically, the tumors were observed within the tumor capsule (C1) in five, outside the tumor capsule but not beyond the midline (C2) in seven, and beyond the midline (C3) in six. In group A, under microscopic examination, the tumor invasion into the renal parenchyma was observed in only three patients among C2 and C3 cases. Tumor vessels from the capsular and/or perforating arteries plus from the intrarenal arteries could be visualized in all patients, three of whom had tumor invasion into the renal parenchyma. In group B, no tumor recurrence around the kidney occurred, and two patients have survived for greater than 2 years. The kidney-preserving radical tumor resection is recommended in surgical treatment of advanced neuroblastoma following preoperative chemotherapy, and is predictable preoperatively by angiography.

On the mechanism of growth of cells (Bacillus amyloliquefaciens) in the mixed aqueous two-phase system

The growth of Bacillus amyloliquefaciens in the aqueous two-phase system, made up of polyethylene glycol, dextran, and water, was investigated. Generally, Bacillus partitions in the dextran phase, but the magnitude of the separation depends largely on the overall composition of polymers in the phase system. The kinetics of growth of Bacillus amyloliquefaciens was studied in the polyethylene glycol-rich continuous phase, dextran-rich dispersed phase, and in the mixed phase. From the kinetic data it appears that increasing the overall polymer composition causes the cells to adsorp at the interface. On the other hand, partition measurements indicate that increasing polymer concentrations make the cell partitioning more one-sided. This anomaly is explained by studying the interfacial adsorption of cells via dynamic surface tension measurements.

Regularity, exposure time and perception of numerosity

Two experiments are described. In Exp. 1, subjects compared the apparent numerosity of two kinds of dot patterns, regular vs irregular, with two different exposures (160 vs 2000 msec.). In Exp. 2, the subjects had to estimate the numerosity of the same patterns, presented one at a time. Analysis showed a relative overestimation of the regular patterns in Exp. 1 but not in Exp. 2. In general an overestimation occurred with an increase in exposure. Such results support our hypothesis of two separate processes as the basis of the two kinds of performance (estimating vs comparison).

Scavenger activity in monocyte-derived macrophages from atherothrombotic strokes

Foam cells are lipid-laden macrophages derived primarily from circulating mononuclear cells and are a characteristic feature of atheromatous lesions. The exact role of these foam cells in the pathogenesis of atherosclerotic lesions remains uncertain, but one potential function is to take-up and process excess interstitial arterial lipoproteins, suggested by their extraordinary ability to engulf enormous quantities of modified low density lipoproteins by the so-called "scavenging pathway." To test this possibility, monocytes from 15 atherothrombotic brain infarct patients and age and sex matched controls were isolated and cultured for 7-8 days in 20% normal serum. The monocyte-derived macrophages were investigated for their ability to bind, internalize and degrade both native and modified (acetylated) LDL labelled with 125Iodine. While native LDL was metabolized similarly, stroke macrophages displayed significantly reduced ability to scavenge modified LDL. These findings suggest that insufficient processing of interstitial arterial cholesterol by monocyte-derived macrophages may contribute to the aggravation of atheroma formation. This inadequacy is likely further compromised by reduced levels of serum high density lipoprotein since the absence of a cholesterol-acceptor will promote the slow but continued accumulation of lipids and the formation of foam cells.

Hypergonadotropic hypogonadism with congestive cardiomyopathy: an autosomal-recessive disorder?

We report on two sisters with ovarian dysgenesis and secondary hypergonadotropic hypogonadism and congestive cardiomyopathy. Their parents are first cousins. It is suggested that these are the main manifestations of a previously unreported autosomal-recessive syndrome.

Emergency valve replacement during acute carditis--case reports

Two patients are described with acute rheumatic carditis and severe heart failure who failed to respond to aggressive medical treatment with steroids, salicylates, inotropic agents and afterload reduction. In both cases, cardiac catheterization revealed severe aortic and mitral regurgitation with preserved myocardial contractility. Emergency double valve replacement was successfully performed with marked improvement in both patients. The diagnosis and evaluation of the condition, as well as the unique problems confronted in the post-operative course are discussed.

Correlation of E. coli K-1 bacteremia and capsular polysaccharide antigenemia in acute and chronic infection

The K-1 polysaccharide is an important virulence factor in human E. coli infections. Using E. coli 016K1, we investigated the kinetic association of bacteremia and K-1 antigenemia in acute lapine and canine infections and in a chronic infection model of neutropenic rats. Additionally, we assessed the presence of K-1 antigenemia in E. coli K-1 bacteremic patients. K-1 was measured by a solid phase radioimmunoassay (RIA) using cross-reactive equine anti-Group B meningococcal IgM. In acute infections, none of the dogs or rabbits developed antigenemia even with a bacteremia of 2 X 10(4) CFU/ml or 5 X 10(5) CFU/ml, respectively. Antigenemia appeared in the rabbit only with an infecting dose of greater than or equal to 5 X 10(8) CFU. In the rat model we observed an initial bacteremia of 10(3) CFU/ml, which increased to 10(6) CFU/ml at 24 hrs. However, antigenemia was most often delayed, appearing in only greater than or equal to 30 hrs postinfection. Percent mortality was directly associated with the degree of bacteremia and antigenemia. In acute human E. coli K-1 bacteremia, 11 of 22 (50%) of patients were positive for K-1 antigenemia. The data demonstrated that K-1 polysaccharide was not usually detectable in the early stages of bacteremia, but occurred only after prolonged infection or very high infecting doses. The RIA to measure K-1 antigenemia would not be a useful diagnostic tool.

Anxiolytic effects of low dosage nitrous oxide-oxygen mixtures administered continuously in apprehensive subjects

We observed the effect of low doses of nitrous oxide on the cardiovascular and respiratory systems, the cortisol output in blood and saliva, and the degree of sedation and analgesia of 20 volunteers. A psychologic screening inventory was also performed. We found nitrous oxide, at low dosage, to be primarily an anxiolytic and not an analgesic or amnesic agent. The nasally inhaled concentrations necessary to induce an anxiolytic effect varied from subject to subject, ranging from 30% to 65% and averaging 35% to 40%. This finding justifies the use of the gas to relieve anxiety instead of nonvolatile parenterally administered psychosedatives and narcotics. Nitrous oxide is preferable because its action is established within several minutes, it is rapidly eliminated at the conclusion of a procedure, and the sensorium is clear after five or six minutes. The gas is simply and safely administered with fail-safe apparatus designed specifically for this purpose. The technic is admirably suited for use in ambulatory care units where minor surgical or dental procedures are performed.

Sensitive measurement of endotoxin by radio-rocket immunoelectrophoresis using [125I] Staphylococcus aureus protein A

Antibody directed against the core glycolipid antigen (CGL) of the mutant Salmonella minnesota Re 595 has been shown to cross-react with endotoxin from bacteria within the group Enterobacteriaceae. Using this cross-reactive CGL antibody we have developed a sensitive (250 pg) radio-rocket immunoelectrophoretic technique to measure endotoxin. We used the principles of rocket immunoelectrophoresis and increased the sensitivity by using 125 I-labelled staphylococcal protein A which serves as a sensitive probe to bind to the Fc portion of the IgG complexed with antigen. The rocket-shaped [125I] protein A labelled immune complexes were detected by radioautography. The sensitivity is 100-fold greater than conventional Coomassie brilliant blue staining. Measurement of CGL was inhibited by normal human serum. However, the assay had the capacity to quantitate endotoxin in buffer extracts of clinically isolated Escherichia coli, Serratia marcescens, Klebsiella pneumoniae but not Pseudomonas aeruginosa. Analysis of various preparations of CGL obtained from different investigators demonstrated wide variation in their immunoreactivity. Because of the significant cross-reaction to detect various endotoxins this method has the potential to measure endotoxemia and assess the immunochemical quality of various endotoxin preparations. Additionally, the technique of using [125I] protein A has wide applicability for the sensitive measurement of other antigens.

Radiocardiography in clinical cardiology

Quantitative radiocardiography provides a variety of noninvasive measurements of value in cardiology. A gamma camera and computer processing are required for most of these measurements. The advantages of ease, economy, and safety of these procedures are, in part, offset by the complexity of as yet unstandaridized methods and incomplete validation of results. The expansion of these techniques will inevitably be rapid. Their careful performance requires, for the moment, a major and perhaps dedicated effort by at least one member of the professional team, if the pitfalls that lead to unrecognized error are to be avoided. We may anticipate more automated and reliable results with increased experience and validation.

The effect of allopurinol on oxypurine excretion in xanthinuria

In a patient with xanthine urolithiasis secondary to hereditary xanthinuria (xanthine oxidase deficiency), allopurinol administration resulted in a 20 per cent increase in oxypurine excretion and an elevation of the urinary xanthine/hypoxanthine ratio from 4.08 to 6.53. The rise in this ratio suggests that residual xanthine oxidase activity may have been present. It is possible that the excessive re-utilization of hypoxanthine and xanthine in this disease prevents the allopurinol-induced inhibition of de novo purine biosynthesis that is seen in normal subjects.

Glycogen and phosphorylase activity in rat brain during recovery from several forms of hypoxia

Images