Long-term engraftment of normal and post-5-fluorouracil murine marrow into normal nonmyeloablated mice [see comments]

We report the successful long-term engraftment of normal male donor bone marrow (BM) transfused into noncytoablated female mice, challenging the assumption that "niches" need to be created for marrow to engraft. We have used chromosomal banding and Southern blot analysis to identify transplanted male marrow cells, and shown the long-term stability of the chimeric marrows. Balb/C, BDF1, or CBA-J female hosts (no irradiation) received for 5 consecutive days 40 x 10(6) male cells (per day) of the same strain, and repopulation patterns were observed. Parallel studies were performed using tibia/femur equivalents of normal marrow or marrow from Balb/C mice pretreated 6 days previously with 150 mg/kg 5-fluorouracil (5-FU). Chromosome banding techniques showed that 5% to 46% of marrow cells were male 3 to 9 months posttransplant with normal donor marrow. Southern blot analysis, using the pY2 probe, showed continued engraftment at 21 to 25 months posttransplant, ranging from 15% to 42% male engrafted cells in marrow. Normal donor male marrow engrafted significantly better than 5-FU-pretreated male marrow as shown 1 to 12 months posttransplant in non-cytoablated female recipients. Percentages of male engrafted cells in BM ranged from 23% to 78% for recipients of normal donor marrow and from 0.1% to 39% for recipients of 5-FU marrow. Mean engraftment for 6 mice receiving normal marrow was 38%, whereas that for 6 mice receiving post-5-FU marrow was 8%, as assayed 1 to 3 months posttransplant. At 10 to 12 months, mean engraftment for the normal donor group was 46%, compared with 16% for the 5-FU group. The patterns of engraftment with normal and 5-FU marrow were similar for spleen and thymus. These results show that long-term chimerism can be established after transplantation of normal donor marrow to normal nonirradiated host mice and indicate that marrow spaces do not have to be created for successful engraftment. They suggest that transplanted marrow competes equally with host marrow for marrow space. Finally, these data show that post-5-FU Balb/C male marrow is markedly inferior in the repopulation of Balb/C female host marrow, spleen, and thymus, and suggest that this population of cells may not be the ideal population for gene transfer studies.     

Retirement patterns and employee benefits: do benefits matter?

This article investigates the impact of postretirement employee benefits on the likelihood that workers expect to retire before age 62 and age 65. Using data from the 1992 Health and Retirement Study, probit regression models were estimated to explore the effect of pension plans and retiree health insurance on the expectation of early retirement. With respect to pension plans, the effects of both the type of pension plan and the expected benefits from those plans are explored. Similar effects were explored for retiree health benefits. The results indicate that postretirement pension benefits and the availability of retiree health benefits have a significant influence on workers' retirement age expectations.     

Macrophage microbicidal activity. Correlation between phagocytosis-associated oxidative metabolism and the killing of candida by macrophages

The mechanisms by which macrophages kill ingested microorganisms were explored using Candida albicans and Candida parapsilosis. The results indicate that efficient macrophage candidacidal activity depends upon the generation of oxygen metabolites by the phagocytic cell: (a) peritoneal macrophages from mice infected with bacillus Calmette-Guerin (BCG) or injected intraperitoneally with lipopolysaccharide (LPS) released more superoxide anion (0(2)(-)) during phagocytosis of candida and killed candida better than did resident macrophages; (b) cells of the macrophage-like line J774.1, which released negligible amounts of O(2)(-), could ingest the candida normally but not kill them; (c) killing of candida by resident, LPS- elicited, and BCG-activated macrophages was inhibited by agents that scavenge O(2)(-), hydrogen peroxide (H(2)0(2)), hydroxyl radical (x OH), and singlet oxygen; and (d) all three macrophage types killed C. parapsilosis more effectively than C. albicans, and (7. parapsilosis stimulated a more prompt and vigorous burst of macrophage oxygen consumption and 0(2)(-) release than did C. albicans. Macrophages ingested C. parapsilosis slightly more quickly than C. albicans, but phagocytosis of both strains was equivalent by 60 min of incubation. Although C. albicans contained higher concentrations of the oxygen-metabolite scavengers superoxide dismutase and catalase, neither fungal species scavenged 0(2)(-) or H(2)0(2) effectively; and C. albicans was killed more easily than C. parapsilosis by a xanthine oxidase system that generates primarily H(2)O(2) at pH 7, or 0(2)(-) and x OH at pH 10. Thus, the decreased killing of C. albicans appears to result primarily from the capability of this species to elicit less vigorous stimulation of macrophage oxidative metabolism. This capability may have general relevance to the pathogenicity of microorganisms.     

Blood preservation. XXXIV. DHA maintains 2,3-DPG and its adverse effect on ATP is reversed with extra phosphate

We have found that the addition of 10 mM inorganic phosphate to DHA in CPD-adenine maintains ATP levels at normal or higher than normal values for six weeks of storage. 2,3-DPG values are slightly lowered by the extra phosphate, but are still maintained at approximately half normal for four weeks by the DHA. The addition of a higher phosphate concentration, 20 mM, to DHA produced lower levels of ATP and 2,3-DPG than those observed with 10 mM phosphate, although both levels were better than in the CPD-adenine control. pH values in this experiment were lowest in the three preservatives containing DHA, probably indicating increased lactate production due to metabolism of this triose sugar, in addition to dextrose present in CPD.     

Spectrin-alpha I/61: a new structural variant of alpha-spectrin in a double-heterozygous form of hereditary pyropoikilocytosis

Recent biochemical studies have led to the identification of abnormal spectrins in the erythrocytes of patients with hereditary pyropoikilocytosis (HPP) and hereditary elliptocytosis (HE). In this report we describe the biochemical characterization of the erythrocytes from a proband with severe HPP who is doubly heterozygous for two mutant spectrins (Sp): Sp alpha I/74 and a new, previously undetected, mutant of alpha-spectrin designated Sp alpha I/61. The proband's erythrocytes are unstable when exposed to 45 degrees C, and her membrane skeletons exhibit instability to shear stress. The content of spectrin in the proband's erythrocyte membranes is decreased to 75% of control values. The amount of spectrin dimers in crude 4 degrees C spectrin extracts is increased (58%) as compared with control values (6% +/- 4%). Limited tryptic digestion reveals a marked decrease in the normal 80,000-dalton alpha I domain, an increase in the 74,000-dalton fragment that is characteristic of Sp alpha I/74, and an increase in a series of new fragments of 61,000, 55,000, 21,000, and 16,000 daltons. Both parents are asymptomatic, but they have increased amounts of spectrin dimers (17% to 25%). Limited tryptic digestion of the father's spectrin demonstrates the presence of a previously identified abnormal spectrin (Sp alpha I/74) that is characterized by a decrease in content of the 80,000-dalton peptide and an increase in concentration of the 74,000-dalton peptide. The mother's spectrin digests show a decrease in the amount of 80,000-dalton peptide and the formation of new peptides of 61,000, 55,000, 21,000, and 16,000 daltons. The data indicate that this severe form of HPP is due to the inheritance of two distinct abnormal spectrins, Sp alpha I/74 and a new spectrin mutant, Sp alpha I/61.     

Protein C deficiency resulting from possible double heterozygosity and its response to danazol

A unique family with protein C (PC) deficiency is described. The proband had a history of renal vein thrombosis as a newborn and iliofemoral thrombosis at the age of 6 years. After 6 months of heparin treatment, discontinuation of anticoagulation therapy was accompanied by persistent hypofibrinogenemia with increased fibrinogen consumption. With continuous infusion of heparin, fibrinogen turnover normalized, and the child has remained free of thrombosis. Both the immunologic level of PC and the functional activity measured by amidolytic assay were moderately reduced (47% and 34%, respectively). Functional activity of PC measured by its anticoagulant activity was disproportionately lower (14%). A 3-year-old asymptomatic sibling had a similar disproportionate reduction of PC anticoagulant activity compared with the amidolytic activity or immunologic level. The mother demonstrated type I PC deficiency with a proportionate reduction in immunologic protein levels (59%), anticoagulant activity (52%), and amidolytic activity (46%), whereas the father had type II PC deficiency with normal immunologic protein levels (102%), normal amidolytic function (98%), but a low anticoagulant function (50%). An abnormal PC molecule was detected by two-dimensional immunoelectrophoresis in the father and two children. These data are consistent with the hypothesis that the children are doubly heterozygous for two different types of PC deficiency inherited from each of the parents. A 14-day trial of danazol in the proband resulted in a rise in the PC antigen concentration from 66% to 98% but no change in PC anticoagulant function.