Carnitine depletion as a probable cause of hyperlipidemia in uremic patients on maintenance hemodialysis

The mechanism of te development of hemodialysis hyperlipidemia was investigated in uremic patients on maintenance hemodialysis. Hemodialysis treatment lost large amounts of carnitine from blood into the dialysate fluid, resulting in the reduction in serum concentration of carnitine. After the treatments were repeated for more than 12 months, the serum concentration of carnitine reduced markedly and the serum triglyceride level increased significantly. In contrast, in patients who had been supplemented with commercial amino acids solution, the serum concentrations of carnitine and lipid were within normal ranges and remained unchanged even after repeated hemodialysis treatments. Carnitine administration also reduced the serum triglyceride level to or towards normal. The results suggest that carnitine depletion induced by hemodialysis treatments has a probable causal relationship to hyperlipidemia in uremic patients on long-term maintenance hemodialysis and that supplementation of carnitine or amino acids prevents carnitine depletion and improves hemodialysis hyperlipidemia.

Conformations of fortimicins and three-dimensional structure-activity relationship in the aminoglycoside antibiotics

The fortimicins are pseudodisaccharide antibiotics consisting of purpurosamine and fortamine moieties which are connected through an alpha-linkage. NMR spectra indicate that the fortamine ring in fortimicin A takes a chair conformation which corresponds to an inverted one in the conformation of fortimicin B free base. Fortimicin A is unstable in solution, and we were unable to obtain any crystals of it. To elucidate the structure of fortimicin A and to clarify the stereochemistry of fortimicins, we have undertaken to calculate their empirical force-fields starting from the X-ray structures of fortamines and fortimicin B free base. Nuclear Overhauser enhancement data were also employed to confirm the calculated relative orientation of the two rings around the glycosidic linkage. The 3-dimensional structure-activity relationship of aminoglycoside antibiotics is discussed on the basis of these results.

Biological activities of antitrinitrophenyl and antidinitrophenyl mouse monoclonal antibodies

The biological activities of mouse IgG1, IgG2a, IgG2b, and IgE monoclonal were investigated. As has been shown with conventional antibodies, monoclonal IgG1 and IgE are the two classes capable of sensitizing the mouse for anaphylactic reactions, IgE sensitizes the rat, and IgG2a sensitizes the guinea pig. What has not been seen with conventional antibodies is that large amounts of monoclonal IgG2a or IgG2b can sensitize the mouse, very large amounts of monoclonal IgE can sensitize the guinea pig, and very large amounts of IgG1 and IgG2a can sensitize the rat. One of the IgG1 monoclonal antibodies was capable of fixing complement by the classical pathway.

The presence of mast cell precursors in rat peripheral blood

Soft agar culture of mononuclear cell fractions prepared from rat peripheral blood yielded numerous colonies consisting of mast cells. The mast cell nature of the cells was established by ultrastructural and histochemical analyses as well as by the demonstration the the colonies contained histamine and that the cells possessed receptors for the Fc component of IgE. Stringent criteria for the distinction of mast cells from monocytes/macrophages that could have metachromatic inclusions were applied. The alcian-blue-safranin technique delineated the maturation of mast cell granules by showing the loss of alcian-blue and increase in safranin-positive organelles presumed to reflect the increase in N-sulfated polysaccharides representing heparin. The mast cells exhibited low or absent reactions for peroxidase, alpha-naphthyl butyrate, periodic acid Schiff, and Sudan black reacting lipid, whereas macrophages stained in parallel were positive for these substances. Since it is known that extracellular conditions may cause variations in phenotypic expression, the observations have led to the hypothesis that mast cells and macrophages may have a common precursor.

Allelic polymorphism of murine IgE controlled by the seventh immunoglobulin heavy chain allotype locus

Two alloantisera against hybridoma-derived IgE detected allotypic determinants expressed on the murine epsilon chain. An antiserum raised in BALB/c mice against monoclonal IgE of C57BL/6 origin reacted exclusively with IgE of strains having Igh-1b (IgG2 a) allotype. The second antiserum, C57BL/6 anti-BALB/c monoclonal IgE, reacted with IgE of strains having Igh-1a, Igh-1d, Igh-1e and Igh-1j allotypes. The genetic studies of (BALB/c x C57BL/6)F1 and backcross F2 animals indicated that the locus controlling the IgE allotype is linked to the Igh-1 locus. This was further confirmed by the possession of respective IgE allotypes by Igh-C congenic mice, BALB/c and BAB-14, C3H.SW/Hz and CWB/Hz. Thus, the allotype detected on the epsilon chain is controlled by the seventh murine immunoglobulin allotype locus, and should be designated as the Igh-7 allotype.

Functional properties of Ly 11.2 lymphocytes: a role for these cells in leukemia?

Functional studies of lymphocyte subpopulations reveal that Ly 11.2, a newly defined T cell surface antigen, is present on prothymocytes and natural killer cells, but not on suppressor T cells for antigen-specific IgE antibody responses, Ly 1+, 2-, 3- helper T cells nor on tumor-specific cytotoxic effector cells. Changes in the expression of Ly 11.2 regularly accompany leukemogenesis and are quite distinct from changes of other cell surface antigens thus far observed. After intrathymic inoculation of radiation leukemia virus (RadLV), many more Ly 11.2-positive cells are found expressing viral antigens than cells expressing other cell surface phenotypes. In addition, after RadLV inoculation, significantly more Ly 11.2-positive cells can be found in the thymus of susceptible mice than in the thymus of resistant mice. The greater availability of permissive (Ly 11.2-positive) cells in susceptible vs resistant hosts at the time when infectious virus is present may account for the shorter latency period and high leukemia incidence of susceptible vs resistant mice.

Functional properties of Ly 11.2 lymphocytes: a role for these cells in leukemia?

Functional studies of lymphocyte subpopulations reveal that Ly 11.2, a newly defined T cell surface antigen, is present on prothymocytes and natural killer cells, but not on suppressor T cells for antigen-specific IgE antibody responses, Ly 1+, 2-, 3- helper T cells nor on tumor-specific cytotoxic effector cells. Changes in the expression of Ly 11.2 regularly accompany leukemogenesis and are quite distinct from changes of other cell surface antigens thus far observed. After intrathymic inoculation of radiation leukemia virus (RadLV), many more Ly 11.2-positive cells are found expressing viral antigens than cells expressing other cell surface phenotypes. In addition, after RadLV inoculation, significantly more Ly 11.2-positive cells can be found in the thymus of susceptible mice than in the thymus of resistant mice. The greater availability of permissive (Ly 11.2-positive) cells in susceptible vs resistant hosts at the time when infectious virus is present may account for the shorter latency period and high leukemia incidence of susceptible vs resistant mice.

Production of monoclonal mouse IgE antibodies with DNP specificity by hybrid cell lines

IgE anti-DNP antibody-secreting hybridomas were obtained by polyethylene glycol fusion of murine myeloma cells with spleen cells from mice, primed with DNP-KLH and challenged with DNP-Nippostrongylus brasiliensis extract. The in vivo and in vitro continuously growing hybridomas are producing high amounts of monoclonal IgE anti-DNP antibodies, which are heat-labile, hapten-specific and have rat mast cell sensitizing capacity.

An electron microscopic study of the surface structures and hemadsorption on chick embryo cells infected with rabies virus

Characteristic alterations at the surface of chick embryo cells infected with the HF-TC strain of rabies virus and the binding sites of hemadsorption were studied employing both scanning and transmission electron microscopes. The initial alteration of the cell surface structure revealed by scanning electron microscopy was an appearance of elongated and reticulated microvilli on the 2nd day after virus inoculation. On the 3rd day, numerous bullet-shaped virions could be seen budding as single, tetrapod-like structures and as radial projections both from the perikarya and microvilli. Thereafter, elongation of microvilli, formation of numerous blebs in various sizes, disappearance of filopodia, and rounding up of infected cells were observed as characteristic cytopathic effects by rabies virus infection. The attachments of goose erythrocytes to the infected cells occured in two forms. The one was adsorption of erythrocytes to the cell surface involving microvilli and filopodia in the absence of detectable virus, and the other was adsorptio n of erythrocytes to the virus particles budding from cell surface. The former could be seen from the early stage of infection through the end of observation period, while the latter was observed only on and after the 3rd day after virus inoculation. These findings were also confirmed with transmission electron microscopy.