239+240Pu and 137Cs concentrations for zooplankton and nekton in the Northwest Pacific and Antarctic Oceans (1993-1996).

The concentrations of 239+240Pu and 137Cs in zooplankton and nekton in the Northwest Pacific and Southern Oceans were measured during the period 1993-1996. The object of the sampling was to assess the potential impacts of existing submerged anthropogenic-radioactive materials in the western North Pacific as well as the East China Sea. Samples from the Bransfield Strait of the Antarctic Ocean provided a control source impacted by only atmospheric bomb fallout. No particularly elevated levels of 239+240Pu were found in zooplankton samples from the Northwest Pacific, although significantly lower levels of 239+240Pu were found in three mixed zooplankton samples from the Bransfield Strait. The body burden of 239+240Pu in zooplankton appears to reflect concentrations in ambient seawater with some variation. Some additional measurements of 137Cs in fish are also reported here to complement existing databases and for future reference in the regional marine environmental radioactivity monitoring effort.

Iodine-129 concentrations in marginal seas of the north Pacific and Pacific-influenced waters of the Arctic Ocean.

Water sampling during the 1993 IV Russian-US Joint Expedition to the Bering and Chukchi Seas (BERPAC) indicates that Pacific Ocean burdens of the long-lived radionuclide 129I are relatively low in the Pacific-influenced Arctic, particularly compared to high latitude waters influenced by the North Atlantic. These low concentrations occur despite the presence of potential submerged anthropogenic sources in the East Sea (Sea of Japan), and in the northwest Pacific Ocean, east of the Kamchatka Peninsula. The concentration of 129I entering the Arctic Ocean through Bering Strait, approximately 0.7 x 10(8) atoms kg(-1), is only slightly higher than observed in deep Pacific waters. Similar concentrations (0.44-0.76 x 10(8) atoms kg(-1)) measured in Long Strait indicate no significant transfer of 129I eastward into the Chukchi Sea in the Siberian Coastal Current from the Siberian marginal seas to the west. However, the concentrations reported here are more than an order of magnitude higher than the Bering Strait input concentration estimated (1.0 x 10(6) atoms kg(-1)) from bomb fallout mass balances, which supports other existing evidence for a significant atmospheric deposition term for this radionuclide in surface ocean waters. Near-bottom water samples collected in productive waters of the Bering and Chukchi Seas also suggest that sediment regeneration may locally elevate 129I concentrations, and impact its utility as a water mass tracer. As part of this study, two deep 129I profiles were also measured in the East Sea in 1993-1994. The near-surface concentration of 129I ranged from 0.12 to 0.31 x 10(8) atoms kg(-1). The 129I concentration showed a steady decrease with depth, although because of active deep water ventilation, the entire 3000 m water column exceeded natural concentrations of the radionuclide. Atom ratios of 129I/137Cs in the East Sea also suggest an excess of 129I above bomb fallout estimates, also possibly resulting from atmospheric deposition ultimately originating from nuclear facilities.

Technical considerations for electromyographic research on the shoulder.

This study compared 2 methods of indwelling bipolar electrode insertion. One method used a single needle for the insertion of both wire leads, and the second method used 2 needles for the independent insertion of both leads at a specified interdetection distance. Simultaneous electromyography recordings from the 2 different electrode configurations were made during the activation of nonfatigued supraspinatus and infraspinatus muscles from 10 healthy subjects. Subjects performed 6 different isometric contractions at 3 different levels of force (100%, 60%, and 30% effort). In this study, the bipolar electrode configuration using 2 hypodermic needles for placement of the 2 leads produced superior electromyography recordings than did the configuration using a single needle for the wire lead insertion. The separated bipolar electrodes produced a significantly higher amplitude electromyography signal with less intersubject variability and greater partial correlation with force. This study suggests an alternative method of bipolar wire electrode placement that results in improved signal characteristics and decreased variability of signal acquisition. A standardization of wire electromyography examination of the shoulder that improves signal characteristics and acquisition ultimately will lead to more accurate results with greater clinical use and validity.

An electromyographic study of arm muscles during climbing.

Upper extremity muscle injuries from rock climbing are common. Knowledge of the activity of specific muscles during climbing may allow the development of training programs to reduce these injuries. This study evaluated the electrical activity of the first interosseous (IN), brachioradialis (BR), flexor digitorum superficialis (FD), and biceps brachii (BB) muscles in seven climbers by integrated electromyography (IEMG) during finger-tip pull-ups. The climbers, with forearms pronated, performed three consecutive pull-ups. Each pull-up consisted of: (1) hanging using four fingers of each hand, (2) pull-up to maximum elbow flexion, (3) slow return to starting position. The IEMG during maximum voluntary contraction (MVC) was obtained for each muscle separately, and the IEMG was normalized to MVC. During hanging, FD showed the highest normalized IEMG (0.64 +/- 0.20). During pull-up, the highest IEMG was produced by FD (0.69 +/- 0.25) and BR (0.67 +/- 0.19), while BB showed only 0.33 +/- 0.12 and IN 0.09 +/- 0.06. During lowering, FD again had the highest IEMG (0.74 +/- 0.24), while the EMG from BR was decreased to 0.42 +/- 0.14 and BB to 0.15 +/- 0.15. BR and BB showed an abrupt peak in EMG during pull-up and lowering, as opposed to FD which remained constantly highly activated, which suggests that FD does not contribute to elbow flexion even though it crosses the elbow joint. The high activation of FD and BR may explain their elevated incidence of injury during climbing. Thus, a reduction in climbing-related muscle injuries may be achieved by a training program that emphasizes conditioning of the BR and FD muscles.

The effect of high-dose short-term ibuprofen on antihypertensive control with hydrochlorothiazide.

The effect of high-dose ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), on the blood pressure of treated hypertensive patients was evaluated in a randomized, placebo-controlled, double-blind, crossover trial with 24-hour ambulatory blood pressure monitoring. Twelve middle-aged black women with essential hypertension, controlled with 50 mg hydrochlorothiazide per day, randomly received 3200 mg ibuprofen and a placebo for 8 days. Each treatment phase was separated by a 1-week washout period. Ambulatory blood pressure monitoring (ABPM), body weight, and 24-hour urinary excretion of sodium, creatinine, and prostaglandin E2 (PGE2) were determined at the end of each treatment phase. Mean (+/- SEM) 24-hour systolic and diastolic blood pressures were 122/85 (+/- 2.9/1.7) and 125/85 (+/- 3.0/1.1) during the placebo and ibuprofen phases, respectively. Mean ABPM during six consecutive 4-hour periods also revealed no significant differences between placebo and ibuprofen. We conclude that 3200 mg ibuprofen per day for up to 1 week induced little change in blood pressure in hypertensive who are receiving hydrochlorothiazide.

Oxygen-18 Content of Atmospheric Oxygen Does Not Affect the Oxygen Isotope Relationship between Environmental Water and Cellulose in a Submerged Aquatic Plant, Egeria densa Planch.

We determined that the oxygen isotopic composition of cellulose synthesized by a submerged plant, Egeria densa Planch., is related to the isotopic composition of environmental water by a linear function, delta(18)O cellulose = 0.48 delta(18)O water + 24.1% per thousand. The observation of a slope of less than 1 indicates that a portion of cellulose oxygen is derived from an isotopically constant source other than water. We tested whether this source might be molecular oxygen by growing plants in the presence of high concentrations of (18)O in the form of O(2) bubbled into the bottom of an aquarium. Cellulose synthesized during this experiment did not have significantly different oxygen isotope ratios than that synthesized by control plants exposed to O(2) of normal (18)O abundance. We propose that oxygen in organic matter recycled from senescent portions of the plant is incorporated into cellulose. Our findings indicate that paleoclimatic models linking the oxygen isotope composition of environmental water to cellulose from fossil plants will have to be modified to account for contributions of oxygen from this or other sources besides water.

Stable carbon isotope ratio variations in marine macrophytes along intertidal gradients.

The hypothesis that relative water motion and boundary layer diffusion processes affect carbon isotope ratios of aquatic plants was tested in tidal pool and surge zone comparisons of the surfgrass Phyllospadix spp. No evidence was found that submerged plants growing in still upper tidal pools were isotopically different from those growing submerged in lower tidal surge zones. Significant decreases in 13C/12C ratios for plants growing emersed in the intertidal may have been caused by uptake of atmospheric carbon dioxide. Marine algae (Egregia menziesii and Halosaccion americanum) growing at the same location and tidal elevations as the seagrasses showed somewhat different isotopic fractionation patterns, suggesting that causes of isotopic variability in the seagrasses were not necessarily the same as those in the two marine algae.

Differentiation-associated changes in in-vitro mRNA translation in the HL60 cell line.

In order to characterize certain aspects of gene expression during the granulocytic differentiation of the HL60 cell line, we have analysed changes in the population of mRNA available for translation in vitro. RNA extracts of DMSO-induced and control cells were translated in vitro in a wheat germ cell-free protein synthesizing system. Translation products were analysed by two-dimensional electrophoresis followed by autoradiography. Autoradiograms were analysed by a computer-assisted method utilizing a drum-scanning microdensitometer. Spots were identified by their relative positions on the films and their relative intensity was estimated. One hundred and eighty-one peptides were identified in both the DMSO-induced and untreated control HL60 cells, 31 of which showed differentiation-associated changes in synthesis in vitro. The 11 peptides which decreased in synthesis did so early in the differentiation process, whereas most of the 20 peptides which increased did so at a later time. Three peptides were shown to increase more than 8-fold by day 4 of induction. A comparison with normal granule proteins from human leukocytes suggests that at least two of these may correspond to functional granule proteins. The changes in peptide patterns which we describe demonstrates that the program of gene expression during HL60 differentiation includes changes in the relative abundance of specific mRNA transcripts. The data described here also provides a standard for comparison of other proteins, such as oncogene products, as they are identified.

Proliferation-associated changes in in vitro mRNA translation in the HL60 cell line.

In order to characterize patterns of gene expression during the proliferation cycle of HL60 cells, we have analysed changes in the population of mRNA available for translation in vitro. HL60 cells were separated into cell cycle phases by centrifugal elutriation, monitoring the separation with flow cytometry. RNA was extracted from cell fractions highly enriched in G1, S or G2+M phases and translated in vitro. Translation products were analysed by two-dimensional electrophoresis followed by autoradiography. Autoradiograms were analysed by a computer-assisted method utilizing a drum-scanning microdensitometer. Spots were identified by their relative positions on the films and their relative intensity was estimated. Of the 159 peptides studied for cell cycle-associated changes in synthesis, nine showed phase-associated changes. The most significant changes were the accumulation of four peptides that showed maximal synthesis only in G2+M phases. An additional four peptides were synthesized maximally in both S and G2+M phases. One peptide showed maximal synthesis in S phase. These changes in gene expression suggest that these relatively abundant transcripts are regulated primarily at a quantitative level during proliferation and may be related to the doubling of structural proteins prior to mitosis.

Studies of leukocyte exudates in cyanate-treated animals.

Cyanate (NCO), which impedes sickling by increasing the oxygen affinity of sickle haemoglobin, may react with many proteins in the body and potentially interfere with many functional systems. Leukocyte glycogen was studies because elevated liver glycogen has been noted after high dose NCO treatment in rats. Leukocyte function was also studied in peritoneal exudates. In animals given NCO alone, blood leukocyte glycogen was 2.8 plus or minus 0.3 (SE) mg per 10+9 WBC while control values were 3.3 plus or minus 0.6, a difference not statistically significant. In casein-induced peritoneal exudates, more WBC were recovered from NCO-treated animals (265 x 10+6 WBC vs. 214 x 10+6 WBC; P = 0.0009). Glycogen in blood leukocytes of casein-stimulated animals was not significantly different from NCO-treated animals. Leukocyte glycogen in peritoneal exudates was markedly increased over blood leukocyte glycogen in both controls (19.4 plus or minus 0.6 vs. 2.7 plus or minus 0.3 mg per 10+9/WBC; P less than 0.0001) and NCO-treated animals (17.5 plus or minus 0.7 vs. 3.6 plus or minus 0.5 mg per 10+9 WBC; P less than 0.001), although levels in exudates from control and NCO-treated animals did not significantly differ from each other. 14-C-glucose incorporation into glycogen was significantly increased (P = 0.020) in exudate leukocytes of NCO-treated animals. Initial phagocytic rates were equal in exudate leukocytes of control and NCO-treated animals. Although NCO treatment has demonstrable effects on ome aspects of leukocyte glycogen metabolism, exudation of leukocytes and phagocytic function are not impaired.