Multi-day radon signals with a radioactive decay limb -- occurrence and geophysical significance.

Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes.     

Assessment of Seasonal Variability of Cytochemical Responses to Contaminant Exposure in the Blue Mussel <Emphasis Type="Italic">Mytilus edulis</Emphasis> (Complex)

A selected suite of cytochemical parameters in Mytilus edulis are altered in response to field and laboratory exposure to chemical contaminants. These biomarkers include lysosomal stability, nicotinamide adenine dinucleotide phosphate (NADPH)–ferrihemoprotein reductase activity, liposfuscin deposition, and accumulation of lysosomal and cytoplasmic unsaturated neutral lipid. Normal variations in physiological processes (influenced by exogenous seasonal changes in temperature, salinity, food availability, etc.) may alter the sensitivity of these biomarkers to contaminant exposure. To address this issue, M. edulis (complex) were sampled monthly from a reference nonurban site (Coupeville, Penn Cove) and a polluted urban site (Seacrest, Elliott Bay) in Puget Sound, WA, for a period of 15 months. Physiological measurements including total length, total weight, somatic and mantle weights (an indication of gonadal development and reproductive status), condition index, and the presence or absence of hemic neoplasia (HN, or leukemia) were recorded. Significant differences in lysosomal stability, lysosomal and cytoplasmic unsaturated neutral lipids, lipofuscin deposition, and NADPH–ferrihemoprotein reductase activity in cells of the digestive gland or digestive tubules were generally found in mussels taken throughout the year from Seacrest compared to mussels sampled from Coupeville, consistent with exposure to chemical contaminants. No seasonally influenced suppression of the entire suite of parameters as measures of contaminant exposure was evident. Therefore these biomarkers can be used to evaluate contaminant exposure in mussels throughout the entire year. Received: 16 December 2001/Accepted: 30 May 2002     

Polyamines in ejaculated ram spermatozoa and their relationship with sperm motility.

Intracellular polyamine levels in ejaculated spermatozoa and seminal fluid from rams were determined by fluorescent spectroscopy of their dansyl derivatives. Relationships between the sperm polyamine content and sperm motility of six mature and eight pubescent rams were studied. Samples were collected from both groups once a month from August through October. Mature rams had a greater percentage of motile sperm cells than lambs (94% versus 73% in September and 92% versus 78% in October); higher spermidine content (36 versus 9 pmol/10(8) cells in September and 162 versus 55 pmol/10(8) cells in October); higher spermine content (984 versus 205 pmol/10(8) cells in September and 1,229 versus 414 pmol/10(8) cells in October); and higher total sperm polyamine content (1,021 versus 216 pmol/10(8) cells in September and 2,258 versus 973 pmol/10(8) cells in October). In the lambs, spermidine content increased (55 versus 9 pmol/10(8) cells); spermine content increased (414 versus 205 pmol/10(8) cells); and total sperm polyamine content increased (973 versus 215 pmol/10(8) cells) in October compared to September. Ejaculates with sperm motility higher than 85% had greater spermine (848 versus 234 pmol/10(8) cells in September and 1064 versus 449 pmol/10(8) cells in October), and total sperm polyamine content (882 versus 244 pmol/10(8) cells in September and 2,015 versus 1,008 pmol/10(8) cells in October) than ejaculates with less than 450 pmol total sperm polyamines/10(8) cells was 68% +/- 6% compared to 90% +/- 4% in cells with greater than 450 pmol (average for all ejaculates) total sperm polyamines/10(8) cells. These data suggest a positive relationship between sperm polyamine constant and sperm motility.(ABSTRACT TRUNCATED AT 250 WORDS)     

A novel 37-Kd adhesive membrane protein from cloned murine bone marrow stromal cells and cloned murine hematopoietic progenitor cells

The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells.