Cation transport and its altered regulations in human stomatocytic erythrocytes.

Cation transport in a population of stomatocytic red blood cells (RBC) is abnormal in the following respects. First, active transport against a gradient, defined as the nonisotopic net accumulation of Na+ or loss of K+ induced by 0.1 mM ouabain, is markedly elevated (7.3 and 6.3 mEq/liter cells/hr for Na+ and K+, respectively), but the Na+:K+ active transport ratio is normal. Apparent uncoupling of the Na+ and K+ isotope transport is due to disproportionately increased ouabain-sensitive 24Na+-23Na+ exchange (32.7 mEq/liter cells/hr), which is measured as a portion of 24Na+ isotope efflux. Second, cation transport is unresponsive to variations in internal Na+ concentration but decreases with decreasing extracellular Na+.     

Rapid Spontaneous Resolution of Vitreomacular Traction Syndrome Documented by Optical Coherence Tomography

A 48-year-old woman presented with a 2-week history of metamorphopsia and reduced vision in her left eye. Visual acuity was 20/30 OS. Slit lamp biomicroscopy fundus evaluation revealed a dull foveal reflex. Optical coherence tomography (OCT) showed attachment of the posterior hyaloid to the macula and significant macular elevation. One month after presentation, visual complaints disappeared. OCT revealed complete posterior vitreous detachment and normal foveal thickness. Although rare, rapid spontaneous resolution of vitreomacular traction syndrome can occur. OCT is a helpful diagnostic tool for following these patients.     

Posteriorly dislocated capsular tension ring.

A 69-year-old man who had pseudoexfoliation and significant nuclear cataract underwent cataract surgery in his right eye. At the beginning of the phacoemulsification, inferior zonulolysis was observed and a capsular tension ring was implanted. Anterior vitrectomy was also performed because of vitreous in the anterior chamber at the end of surgery. A tear in the posterior capsule could not be identified. Three days after surgery, the capsular tension ring was observed partially in the anterior vitreous. A 3-port pars plana vitrectomy was performed and the ring was removed. Three weeks later, the eye developed retinal detachment and was successfully repaired. Retinal complications can develop if the capsular tension ring moves into the vitreous.     

In vivo leukemic transformation: cytogenetic evidence of in vivo leukemic transformation of engrafted marrow cells.

A 4-year-old girl with acute myeloblastic leukemia was treated with 50 mg/kg cyclophosphamide daily for 4 days before being given 1.7 X 10(8) bone marrow cells/kg from her HL-A identical, MLC nonreactive, cytogenetically normal brother. The patient died 92 weeks after the marrow graft. Postmortem examination showed increased myeloblasts and promyelocytes. Cytogenetic studies before transplantation showed that all sex determination metaphases had an XX pattern, and 41% of the hyperdiploid metaphases had an additional 19-20(F) chromosome. At autopsy all hyperdiploid metaphases with XY pattern and 43% of the hyperdiploid metaphases with an XX pattern had an additional F chromosome. Occasional metaphases with 47, XX, + F or 47, XY, + F were seen during the follow-up studies. These findings indicated that an acute leukemia had developed in the XY cell line of this artifically induced sex chimeric child. This suggests that a leukemic stimulus other than that proposed to be induced by total-body irradiation existed in this patient and transformed the engrafted cells.     

THE ENHANCEMENT OF BACTERIAL PHAGOCYTOSIS BY SERUM : THE ROLE OF COMPLEMENT COMPONENTS AND TWO COFACTORS

The role of serum factors in the phagocytosis of pneumococci was studied employing a spectrophotometric assay which measures reduced nitro blue tetrazolium (NBT) dye. Dye reduction occurs within the phagocyte shortly after bacterial ingestion as measured by the phagocytic index technique and by the uptake of ¹²⁵I-pneumococci. Bacteria prepared with γG antibody were not phagocytosed unless a small volume of fresh normal serum was added. Using fresh sera deficient in single complement components, it was demonstrated that the first four components are necessary for optimal bacterial phagocytosis. When highly purified complement components were added to the antibody-coated pneumococci, enhancement of phagocytosis was achieved only with the sequential addition of C1, C4, C2, and C3. Evidence has been presented that human C3 bound to an immune complex exhibits peptidase activity and that this activity is essential for phagocytosis. A heat-labile, dialyzable serum cofactor which enhances C3 peptidase activity enhanced the phagocytosis of pneumococci prepared with purified complement components. A second phagocytosis-promoting cofactor, which is not a complement component, was found to be a heat-labile, 5–6S, beta pseudoglobulin. This protein may stabilize C3 peptidase activity or inhibit enzymatic inactivation of C3.