A new one-step method for the isolation of human mononuclear cells.

This paper describes a radical new, one-step method for the routine isolation of the mononuclear cells from human blood in high yield and purity. In this procedure the blood sample is mixed with a Nycodenz separation medium prior to centrifugation. Erythrocytes and polymorphogranulocytes are pelleted during centrifugation leaving the mononuclear cells in the supernatant. The method can be used for a wide range of blood sample volumes and can be carried out with greater ease than the currently accepted methods.

A new, rapid, one-step method for the isolation of platelets from human blood.

We describe a new, rapid method for the isolation of platelets from human blood using a single centrifugation step through Nycodenz, an inert, nontoxic, nonionic medium. As judged by aggregation and nucleotide release studies, the platelets are recovered in high yield and in excellent functional condition.

Carotenoid composition and antioxidant potential in subfractions of human low-density lipoprotein.

Carotenoids and vitamin E are transported in human plasma complexed with lipoproteins. The bulk of them are associated with low-density lipoprotein (LDL), in which form they may act as antioxidants and thus delay the onset of atherosclerosis. We used a simple, rapid, ultracentrifugation technique to fractionate plasma lipoproteins in self-generating gradients of iodixanol (Optiprep), a non-ionic iodinated density gradient medium. The carotenoid content and composition of a number of LDL subfractions was determined by reversed-phase high-performance liquid chromatography. Lycopene, beta-carotene and beta-cryptoxanthin were mainly located in the larger, less-dense LDL particles whereas lutein and zeaxanthin were found preferentially in the smaller, more dense LDL particles. When the antioxidant content of these fractions was expressed per milligram of LDL protein, significantly lower concentrations of carotenoid and vitamin E were found to be associated with the smaller, protein-rich fractions of LDL. Strong positive correlations were found between total carotenoid and vitamin E plasma concentrations and the lag-time of Cu(2+)-mediated oxidation of LDL subfractions. The more dense LDL subfractions, which had lower levels of these antioxidants, were more readily oxidized, highlighting their possible role in atherosclerotic events.

Surgical management of chronic tophaceous gout. A case report.

Severe chronic tophaceous gout can be a surgical challenge. A classic case of marked first and fifth metatarsophalangeal joint involvement is presented.

The Herbert bone screw and its applications in foot surgery.

The author presents multiple indications of the Herbert bone screw in foot surgery. Both cannulated and noncannulated systems are discussed along with operative steps for several of the more common procedures performed by the author with this type screw. The Herbert bone screw systems provide another alternative for internal fixation to the surgeon.

Magna-FX cannulated screw system and powered metaphyseal stapler in triple arthrodesis.

The author introduces two relatively new means of internal fixation for triple arthrodesis. These new methods not only help to reduce intraoperative time, but also provide an excellent, more precise method of internal fixation. A case report and discussion on the use of these devices are included.

Effect of ligand binding on the buoyant density of DNA in Nycodenz gradients.

The effect of ligand binding upon the buoyant density of DNA in Nycodenz gradients has been studied using DNAs of differing base compositions. The effect of both intercalating ligands (ethidium bromide and proflavin) and non-intercalating ligands (distamycin A, DAPI and netropsin) has been studied. The binding of intercalating ligands to DNA has essentially no effect on the buoyant density of DNA in Nycodenz gradients. The non-intercalating ligands were found to increase the buoyant density of DNA in a base specific manner. The increase in buoyant density can be interpreted in terms of disruption of the hydration shell of the DNA molecule caused by the binding of the ligand along the minor groove of the DNA helix.

Morphological and functional characteristics of mouse mammary carcinoma cells separated on Nycodenz columns.

Tissue from four mouse mammary carcinomas was enzymatically disaggregated and cells from the resulting cell suspension were fractionated on a discontinuous density gradient column (5-20%) of Nycodenz (Nycomed A.S. Oslo). The cell fractions separating at the 10-15% and 15-20% interfaces (density 1.082 and 1.110 g/ml respectively) contained a mean of 83.2 +/- 10.8 (s.d.) and 79.9 +/- 17.4 tumour cells. Compared with the original cell suspension these cell bands contained less cell aggregates and cell debris. The cells in the bands also showed an equivalent ability to grow in tissue culture and to form pulmonary tumours on i.v. injection into isogenic mice, when compared with the tumour cells in the original suspension. The relatively pure preparations of carcinoma cells thus separated may be of value in limiting the unwanted effect of normal cell contamination when testing neoplastic cells in vitro for sensitivity to drugs or hormones.

A rapid method for the preparation of the neutrophil fraction of granulocytes from human blood by centrifugation on isotonic Nycodenz gradients.

A rapid method for the preparation of neutrophils of the granulocyte fraction of human blood is described. A leucocyte-rich fraction is loaded onto preformed isotonic Nycodenz gradients, formed by mixing a stock isotonic Nycodenz solution with a NaCl diluent solution. After low speed centrifugation a neutrophil fraction of high viability, yield and purity can be isolated from the gradients.