Heavy metals (Cu and Zn) in recent sediments of Llangorse Lake,Wales: non-ferrous smelting,Napoleon and the price of wheat — a palaeoecological study

Elevated concentrations of Cu and Zn have been found in the upper part of three sediment cores collected from Llangorse Lake, in south Wales. Palaeomagnetic evidence from one of the cores and ²¹⁰Pb analysis of another, suggests that the increase in sediment Cu and Zn concentrations began during the eighteenth century. A sharp increase in the concentrations of these metals in the sediment profile appears to have occurred during the latter part of the eighteenth century and these concentrations remained high until the mid to late nineteenth century.The absence of known ore deposits and industry around the lake suggests that the lake and catchment soils were increasingly contaminated by long-range aerial transport of emissions from the expanding activity of Cu and Zn smelters located some 80 km upwind in the Swansea area during the Industrial Revolution. Evidence from agricultural crop returns indicates a significant increase in the amount of land devoted to tillage in the catchment, particularly to cereal production, during the late eighteenth and the first half of the nineteenth century which included the Napoleonic Wars. This agricultural shift appears to coincide with increased concentrations of Cu and Zn in the lake sediments. It is suggested that newly ploughed soils, contaminated with metals for many years by long-range aerial transport from the Swansea area, eroded, and were carried into the lake by catchment run-off and added to the sediment burden of Cu and Zn. A subsequent decline of Cu and Zn emissions due to the collapse of the non-ferrous smelting industry and reduced soil erosion because of a 50% reduction of tillage due to an agricultural depression in the second half of the 19th century may explain the fall in Cu and Zn concentrations in the upper part of the sediment profile. The most recent sediments (20th century) show the increase in heavy metals characteristic of many lakes around the world.     

Major histocompatibility complex (MHC)-encoded HAM2 is necessary for antigenic peptide loading onto class I MHC molecules.

The mutant murine lymphoma cell line RMA-S is unable to present endogenous antigens due to its inability to efficiently assemble class I major histocompatibility complex molecules and antigenic peptides. Therefore, it has been suggested that RMA-S cells are defective either in peptide generation or in peptide transport into the endoplasmic reticulum, where class I major histocompatibility complex molecule assembly is believed to occur. As proteasomes and the putative peptide transporters HAM1 and HAM2 have been implicated in class I antigen processing, we have investigated their expression in RMA-S and its wild-type counterpart RMA. Both proteasomes and HAM1 proteins are expressed at similar levels and show identical subcellular distributions in the two cell lines. However, only one copy of the HAM2 gene is present in RMA-S cells, and it contains a point mutation that leads to a premature stop codon. Thus, the HAM2 protein is absent from RMA-S cells. These data demonstrate that HAM2 is essential for peptide loading onto class I molecules.     

Neutrophil aggregation is beta 2-integrin- and L-selectin-dependent in blood and isolated cells.

Neutrophil aggregation in response to formyl peptide was analyzed in blood and isolated cells by fluorescence flow cytometry. The isolated leukocyte aggregates and the leukocytes in blood were identified with the vital nucleic acid stain LDS-751. This method enabled us to discriminate nucleated cells from other blood cells and to detect granulocyte aggregates without isolation or E lysis. Cells isolated in the absence of endotoxin retained the characteristics of cells in blood and exhibited similar aggregation kinetics and dose-response to formyl peptide. We show that it is possible to analyze epitope expression in blood with homogeneous flow cytometric assays and that carefully isolated neutrophils retain the expression characteristics of those in blood. The expression of CD18 was at its lowest levels in unstimulated cells, while the rate of formyl peptide stimulated aggregation was most rapid in these cells. Aggregation in isolated cells as well as blood preceded an increase in receptor expression. After stimulation, L-selectin expression decreased in both blood and isolated cells over a time frame similar to disaggregation. The aggregation response in blood was blocked by pretreatment with antibody to CD18 over a concentration range consistent with the amount of antibody bound. Aggregation was also blocked in isolated cells and blood by antibodies DREG-200 and DREG-56 to L-selectin, but not by isotype controls or anti-LFA-1. The results are discussed in terms of the roles of adhesive receptor expression and recognition in neutrophil aggregation. The methods validated here permit linkage between isolated cells and in vivo studies.     

Functional heterogeneity between NKR-P1bright/Lycopersicon esculentum lectin (L.E.)bright and NKR-P1bright/L.E.dim subpopulations of rat natural killer cells.

In this report, we present data on heterogeneity of rat NK cells utilizing a combination of antibody and lectin-binding characteristics. Among NKR-P1bright NK cells, two discrete populations characterized as Lycopersicon esculentum lectin (L.E.)bright (60 to 80%) and L.E.dim (20 to 40%) were identified by flow cytometry. Comparison of the morphology of sorted NKR-P1bright/L.E.bright and NKR-P1bright/L.E.dim cells indicated that both were greater than 90% LGL. An analysis of the functional capabilities of the sub-populations indicated that NKR-P1bright/L.E.bright NK cells were more efficient in lysis of YAC-1 target cells (1743 LU20/10(7) cells) than were NKR-P1bright/L.E.dim cells (504 LU20/10(7) cells). Conversely, NKR-P1bright/L.E.dim NK cells were much more efficient at lysis of antibody-sensitized erythrocytes (antibody-dependent cellular cytotoxicity (ADCC)) (1412 LU20/10(7) cells) than were NKR-P1bright/L.E.bright cells (165 LU20/10(7) cells). Lysis of antibody sensitized P815 target cells yielded similar results as NKR-P1bright/L.E.dim cells and NKR-P1bright/L.E.bright cells had 905 LU20/10(7) and 189 LU20/10(7), respectively. Additional experiments indicated that NKR-P1bright/L.E.bright NK cells had the capacity to trigger lytic activity via NKR-P1 whereas NKR-P1bright/L.E.dim NK cells did not. NKR-P1bright/L.E.bright sorted cells had a greater capacity to form conjugates with YAC-1 target cells than did NKR-P1bright/L.E.dim sorted cells. Conversely, NKR-P1bright/L.E.dim NK cells were demonstrated to form E-A rosettes whereas the NKR-P1bright/L.E.bright NK cells were not. Additional experiments indicated that tomato lectin itself was not responsible for the differences in reverse ADCC activity or ADCC activity among the subsets. However, lysis of YAC-1 target cells was modulated to some degree by the lectin. These data indicate that NKR-P1bright/L.E.bright and NKR-P1bright/L.E.dim subpopulations of rat NK cells have different capacities for: 1) triggering through NKR-P1; and 2) E-A rosette formation and lysis of antibody-sensitized target cells by ADCC.     

Alterations in cell-surface carbohydrates of rat large granular lymphocytes associated with interleukin-2 activation

The activation of large granular lymphocytes (LGLs)/natural killer (NK) cells with interleukin-2 (IL-2) has been shown to increase the ability of these cells to lyse NK-resistant tumor target cells. Activated LGLs, termed LAK (lymphokine-activated killer) cells, have been demonstrated to be of therapeutic value in vivo against metastatic tumors. The mechanism by which IL-2 induces broadened cytolytic capability, as well as the molecular basis of target recognition and killing by the activated cells has not yet been elucidated. Since carbohydrate moieties have been demonstrated to be of possible significance in the cytolytic cascade of a variety of effector cells, the current study was undertaken to determine if the activation of LGLs with IL-2 is accompanied by an alteration of cell-surface carbohydrates. Two-color flow cytometry was performed to identify LGL/NK cells in populations of nylon wool-nonadherent splenic mononuclear cells and to assess the binding of various lectins to activated as well as nonactivated LGLs. Increases were observed in the binding of four lectins to LGLs after IL-2 activation; Triticum vulgaris (wheat germ agglutinin), Phytolacca americana (pokeweed mitogen), Lycopersicon esculentum (tomato lectin), and Griffonia simplicifolia I-B4 (GSI-B4). The wheat germ, pokeweed, and tomato lectins recognize complex carbohydrates structure consisting of GlcNAc(Bl,4GlcNAc)n while GSI-B4 recognizes alpha-D-galactose terminal end groups. Lectin binding to the activated LGLs was homogenous (i.e., flow cytometry revealed only a single population of fluorescent cells). Lectin binding to LGLs prior to activation was more heterogeneous, however, the tomato lectin uniquely revealed a bimodal distribution of receptors. These data indicate that LGL/NK cells from the rat are heterogeneous in their ability to bind specific lectins, and that IL-2 activation of these cells results in altered expression of specific cell-surface carbohydrates.     

Diurnal patterns of testosterone, dihydrotestosterone, estradiol, and cortisol in serum of rhesus males: Relationship to sexual behavior in aging males

This study was carried out to determine differences between old and young rhesus males in levels and diurnal patterns of testosterone, dihydrotestosterone, cortisol, and estradiol, and to determine correlations between these hormones and sexual behavior of the old males. Blood was drawn from old (n = 9) and young (n = 9) rhesus males over 5 consecutive days at 0900, 1300, and 2100 hr. The two groups of males did not differ in mean serum levels of testosterone, dihydrotestosterone, or estradiol at any time. Although the old and young did not differ in cortisol levels at 0900 and 1300 hr, the cortisol levels at 2100 hr were lower in the old males. Diurnal variations in testosterone, dihydrotestosterone, and cortisol were comparable in old and young males. Mean serum levels of estradiol were significantly higher at 0900 hr than at 1300 hr in the old males, whereas in the young males estradiol levels did not differ with time of day. There was a significant positive correlation between testosterone and yawning rate, and cortisol levels were correlated positively with rate of contacting, rate of mounting, and percentage of tests with erections. The decline in sexual performance of old rhesus males cannot be attributed to changes in the levels or diurnal patterns of testosterone, dihydrotestosterone, or estradiol, but lower cortisol levels in old males may contribute to the decline in sexual behavior.     

Characterization of lysosomal hydrolases that are elevated in Gaucher's disease.

Although Gaucher's disease occurs in three distinct forms with greatly varying degrees of severity, there is no correlation between the clinical course of the disease and levels of residual glucocerebrosidase, the fundamental enzymatic deficiency. In an effort to study secondary changes which might contribute to the pathology of Gaucher's disease, homogenates of spleen, liver, and brain tissue, as well as serum from patients with Gaucher's disease were analyzed for their content of a number of lysosomal enzymes. Extracts of 8 Gaucher spleens contained 3- to 4-fold increases in acid phosphatase activity as well as 5-to 10-fold increases in galactocerebrosidase⁵ activity. The marked elevation in galactocerebrosidase activity in Gaucher spleen was documented using various [³H]galactose labeled galactocerebrosides as substrates and with [³H]galactose labeled lactocerebroside under the “lactosylceramidase I”⁵ assay conditions established by Suzuki (Tanaka, H., and Suzuki, K., 1975, J. Biol. Chem., 250, 2324–2332) that measure galactocerebrosidase activity specifically in the presence of G_mi-ganglioside β-galactosidase. Acid phosphatase determinations using extracts of liver from a case of infantile, neuropathic Gaucher's disease revealed a 2-fold elevation in this activity, whereas brain acid phosphatase activity in this case was similar to that of control tissue. Separation of hexosaminidase A and B activities on DEAE-Sephadex columns indicated increases in both forms of the enzyme in Gaucher tissue with the major increase occurring in the hexosaminidase B component. Glucuronidase and nonspecific esterase were observed to be elevated approximately 2-fold. However, not all lysosomal enzyme activities were increased. Levels of splenic arylsulfatase A and B, α-arabinosidase, sphingomyelinase, α-mannosidase, and G_mi-ganglioside β-galactosidase activities in Gaucher spleen were unremarkable. G_mi-ganglioside β-galactosidase was measured using 4-methylumbelliferyl-β-d-galactopyranoside and [³H]galactose labeled lactocerebroside under the specific assay conditions described by Suzuki for the determination of “lactosylceramidase II” activity. Although levels of arylsulfatase A and B in Gaucher spleen were similar to those of control tissue, arylsulfatase A activity was markedly reduced (20% of control) in homogenates of brain from the case of infantile (type 2) Gaucher's disease. The metabolic and pathologic consequences of these changes in lysosomal enzymes in Gaucher's disease are discussed.     

Identification of four classes of cell surface antigens appearing at gastrulation in sea urchin embryos

An antiserum to isolated membranes of gastrula-stage embryos of the sea urchin Lytechinus variegatus was characterized by absorption and cell agglutination specificities. The antiserum was found to recognize four distinct classes of antigens on the embryonic cell surface: (1) an early embryonic class or “maternal” class present from the earliest stages of development, (2) an embryonic class of antigens which appeared on all cells beginning at gastrulation, (3) a class of antigens present on ectoderm cells, and (4) a class of antigens present on endoderm cells. All four classes of antigens were shown indirectly to be synthesized on embryonic mRNA since a hybrid embryo of the cross Tripneustes ♀ × Lytechinus ♂ expressed all four classes of Lytechinus-specific antigens beginning at gastrulation. Each class was Lytechinus specific in that hybrid cells were agglutinated if beyond the beginning of gastrulation, while normal Tripneustes ♀ × Tripneustes ♂ cells were not agglutinated.     

Xanthine oxidase activity in rat serum after administration of homogenized bovine cream preparation

Rats were given a single dose of saline, saline supplemented with xanthine oxidase (XO), half cream and half milk (H/H) and H/H supplemented with XO. XO was determined by a spectrophotometric method at 297 nm in serum at 0, 2, 4 and 6 hours after administration. The method is rapid, reliable and compares favorably with reported assays. No significant difference was obtained between the two saline treatments. The XO activity in serum of animals receiving the H/H increased significantly at 2 hours and then decreased. The H/H supplemented with XO demonstrated a maximum activity in serum at 4 hours and then declined to a value similar to that of the H/H treatment and below the XO level at 0 time. The initial increase in XO activity in serum of rats receiving the H/H treatments may indicate that XO is absorbed in the gastrointestinal tract or that the H/H materials stimulated endogenous XO activity.