Hydrothermal impacts on trace element and isotope ocean biogeochemistry.

Hydrothermal activity occurs in all ocean basins, releasing high concentrations of key trace elements and isotopes (TEIs) into the oceans. Importantly, the calculated rate of entrainment of the entire ocean volume through turbulently mixing buoyant hydrothermal plumes is so vigorous as to be comparable to that of deep-ocean thermohaline circulation. Consequently, biogeochemical processes active within deep-ocean hydrothermal plumes have long been known to have the potential to impact global-scale biogeochemical cycles. More recently, new results from GEOTRACES have revealed that plumes rich in dissolved Fe, an important micronutrient that is limiting to productivity in some areas, are widespread above mid-ocean ridges and extend out into the deep-ocean interior. While Fe is only one element among the full suite of TEIs of interest to GEOTRACES, these preliminary results are important because they illustrate how inputs from seafloor venting might impact the global biogeochemical budgets of many other TEIs. To determine the global impact of seafloor venting, however, requires two key questions to be addressed: (i) What processes are active close to vent sites that regulate the initial high-temperature hydrothermal fluxes for the full suite of TEIs that are dispersed through non-buoyant hydrothermal plumes? (ii) How do those processes vary, globally, in response to changing geologic settings at the seafloor and/or the geochemistry of the overlying ocean water? In this paper, we review key findings from recent work in this realm, highlight a series of key hypotheses arising from that research and propose a series of new GEOTRACES modelling, section and process studies that could be implemented, nationally and internationally, to address these issues.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

Tritium-helium dating in the sargasso sea: a measurement of oxygen utilization rates.

The newly developed technique of "tritium-helium dating" has been used to investigate in situ rates of oceanic oxygen utilization. As an example, an apparent oxygen utilization rate of 0.20 +/- 0.02 milliliter per liter of water per year has been obtained for the Subtropical Mode water (18 degrees C water) in the Sargasso Sea.

Advection of pore fluids through sediments in the equatorial East pacific.

Measurements of the ratio of helium-4 to helium-3 and of calcium ion in the pore waters of sediments at two locations in the eastern equatorial Pacific indicate that solution advection is occurring through the sediments. Both the helium ratio and the calcium ion profile yield velocity values for advective flow of about 20 centimeters per year. Mass balance constraints are also consistent with the interpretation presented. Flow appears to be occurring thorugh relatively thick sediments, on the order of 300 meters.

A Climatic Freshening of the Deep Atlantic North of 50{degrees}N over the Past 20 Years.

Observations made in summer 1981 show a significant and widespread decrease in salinity, averaging 0.02 per mil, in deep waters of the subpolar North Atlantic over the past two decades. This implies a relatively rapid response of deep water formation to climatic perturbation.

The role of dopamine in the nucleus accumbens and striatum during sexual behavior in the female rat.

Dopamine in dialysate from the nucleus accumbens (NAcc) increases during sexual and feeding behavior and after administration of drugs of abuse, even those that do not directly activate dopaminergic systems (e.g., morphine or nicotine). These findings and others have led to hypotheses that propose that dopamine is rewarding, predicts that reinforcement will occur, or attributes incentive salience. Examining increases in dopamine in NAcc or striatum during sexual behavior in female rats provides a unique situation to study these relations. This is because, for the female rat, sexual behavior is associated with an increase in NAcc dopamine and conditioned place preference only under certain testing conditions. This experiment was conducted to determine what factors are important for the increase in dopamine in dialysate from NAcc and striatum during sexual behavior in female rats. The factors considered were the number of contacts by the male, the timing of contacts by the male, or the ability of the female to control contacts by the male. The results indicate that increased NAcc dopamine is dependent on the timing of copulatory stimuli, independent of whether the female rat is actively engaged in regulating this timing. For the striatum, the timing of copulatory behavior influences the magnitude of the increase in dopamine in dialysate, but other factors are also involved. We conclude that increased extracellular dopamine in the NAcc and striatum conveys qualitative or interpretive information about the rewarding value of stimuli. Sexual behavior in the female rat is proposed as a model to determine the role of dopamine in motivated behavior.

Rh(D) fraction incompatibility causing hemolytic disease of the newborn. Report of two cases in a Chinese family.

Two cases of hemolytic disease of new born in a Chinese family are reported. The hemolysis was due to the production in the mother of antibodies against fractions A, C, and D of Rh(D) antigen. The fractions were absent in the mother's red blood cells which are Rh(DB) but present in her babies. Rh(DB) may be detected by the use of two types of anti-D sera, one with and the other without anti-DB activity. For transfusion purpose, all DB patients so tested, would be regarded as Rh(D) negative.

Efficacy of clonidine in treatment of alcohol withdrawal state.

Clonidine hydrochloride 5 micrograms/kg and placebo were given orally to 11 patients experiencing well-developed alcohol withdrawal states. Active drug and placebo were given in a randomised, cross-over double blind fashion 2 h apart. Clonidine significantly suppressed heart rate (P = 0.002), arterial blood pressure (P = 0.006), and an accumulated score of withdrawal symptoms and signs (P = 0.004). These data suggest that clonidine may be useful in the management of alcohol withdrawal states, and that the underlying pathophysiology of at least some of these manifestations may be sympathetic nervous system hyperactivity.

The long-term storage of blood for transfusion using an improved container for freezing the red cells in liquid nitrogen.

Considerable experience has been gained in the operation of a bank of blood frozen in liquid nitrogen. The procedure for freezing and recovering the red cells is, in principle, that described by Krijnen, Kuivenhoven, and de Wit (1970). An improved metal freezing container offers greater freedom from liquid nitrogen leaks and hence, bacterial contamination. Over 500 units of blood have been preserved and used for transfusions without mishap, and many advantages are seen in this relatively economical method for the long-term storage of blood.

Assay of anti-D using the Technicon Auto-Analyzer and the international standard anti-D typing serum.

A method is described for the automated quantitation of the anti-D content of sera. This procedure is far more reproducible than current manual techniques. The use of the International Standard anti-D typing serum in the calibration of a working standard enables results to be expressed in mug/ml of antibody protein.

Serum glutamate dehydrogenase is not a reliable marker of liver cell necrosis in alcoholics.

Serum glutamate dehydrogenase (EC 1.4.1.3.) activity was measured in 73 hospital patients who had a history of chronic alcohol abuse and who all had a liver biopsy performed. High levels of serum GDH activity occurred in those patients with recent excess alcohol consumption independently of the underlying liver histology, and did not discriminate between those patients with and those without alcoholic hepatitis.

Mechanized blood grouping: a hospital trial using an 8-channel grouping machine.

ABO and Rh (D) groups of 6403 blood samples were assessed on an 8/9-channel autoanalyser in the Serology Department of the London Hospital; the results were independently checked at the Regional Blood Transfusion Centre, Brentwood, using the routine methods for grouping donor blood. Results of this comparative study are given and instances are described in which anomalous results or incorrect groupings occurred; the possible causes are discussed. The 8/9-channel automated blood group analyser is evaluated in terms of routine hospital laboratory practice.

Role of the striatum and nucleus accumbens in paced copulatory behavior in the female rat.

Female rats engage in a series of approach and avoidance behaviors (pacing behavior) directed at the male in order to achieve a preferred rate of intromissions that make pregnancy more likely to occur with insemination. The striatum and nucleus accumbens have been implicated in the modulation of pacing behavior. It is unclear, however, whether these areas of the brain are necessary for the display of pacing behavior. To address this question, ovariectomized female rats received either bilateral quinolinic acid lesions of the striatum or nucleus accumbens or sham surgeries. After hormone priming, rats were allowed to engage in mating behaviors in an apparatus in which they could pace the rate of the copulatory bout. There was a significant reduction in pacing efficiency after striatal lesions, in that females were less likely to leave the male's side of the chamber after a contact. Animals with lesions of the nucleus accumbens that included the shell were more likely to avoid sexual interaction altogether than animals with control lesions. Therefore, it is concluded that the striatum and nucleus accumbens modulate specific aspects of pacing behavior in the female rat.

Critical periods for the effects of alcohol exposure on brain weight, body weight, activity and investigation.

Using an animal model of fetal alcohol syndrome - which equates peak blood alcohol concentrations across different developmental periods - critical periods for the effect of alcohol on brain weight, activity and investigative behavior were examined. The periods of alcohol exposure were from gestational day (GD) 1 through 10, GD 11 through 22, postnatal day (PD) 2 through 10, or all three periods combined. The critical period of alcohol exposure for an increase in activity in juveniles was GD 11 through 22. This pattern was not seen in the same animals in adulthood; instead, increases in both activity and investigation were seen in animals exposed from PD 2 through 10 and not seen in animals exposed during all three periods combined. Brain weight was reduced by alcohol exposure from GD 11 through 22, PD 2 through 10 and all three periods combined. The period from PD 2 through 10 was the only period when the brain weight to body weight ratio was reduced. In conclusion, exposure to alcohol during the periods in the latter half of gestation or early postnatal period seem to have the most deleterious effects on the brain, activity and investigation in the rat. In addition, the effects of alcohol exposure over both the prenatal and postnatal period cannot be easily predicted from the effects of shorter periods of exposure.

The preparation of human intrinsic factor-cobalamin complex from human gastric juice by immunoadsorption.

Immune complexes of human intrinsic factor were prepared by mixing gastric juice saturated with vitamin B12, and sera from patients with pernicious anaemia that had a high proportion of binding (Type II) antibody. The complexes were isolated by sodium sulphate precipitation followed by Sephadex G-150 gel filtration. Acid conditions dissociated the immune complexes and allowed separation of specific antibody and purified antigen bound to vitamin B12 by Sephadex G-200 gel filtration. Specific antibody was covalently attached to Protein A Sepharose CL-4B by coupling with water soluble carbodiimide which allowed intrinsic factor-B12 complex to be purified directly from gastric juice. The intrinsic factor obtained after iodination, ran as a single band on SDS-polyacrylamide gel electrophoresis and was biologically active.

Mitochondrial enzyme activities in liver biopsies from patients with alcoholic liver disease.

The hypothesis that mictochondrial damage is a significant factor in the pathogenesis of alcoholic liver disease (ALD) was investigated by enzymic analysis of mitochondrial fractions isolated from needle biopsy specimens from control patients, patients with fatty liver due to chronic alcoholism, and from patients with other forms of liver disease. Enzymes associated with the inner and outer mitochondrial membranes showed normal levels in ALD. Enzymes associated with the mitochondrial matrix, glutamate dehydrogenase, malate dehydrogenase and aspartate aminotransferase showed significantly raised levels in ALD, but the levels in patients with non-alcoholic liver disease was normal. In addition, analysis of the mitochondria by sucrose density gradient centrifugation revealed no differences between control tissue and liver from patients with alcoholic liver disease. These results do not indicate that there is significant mitochondrial damage in ALD. The raised mitochondrial matrix enzymes may represent an adaptive response to the ethanol load.

Genetic factors in determining susceptibility to alcohol dependence and development of alcohol-induced liver disease.

There is considerable evidence in favour of genetic factors influencing excessive drinking behaviour and development of alcohol dependence (alcoholism), although readily identified markers of these genes have not been established. In addition, environmental factors undoubtedly play an important role. Although the probability of developing a significant liver disease (alcohol-induced hepatitis with or without cirrhosis) is related to the amount of alcohol ingested, there is a great variation in susceptibility which presumably stems from either genetic or additional environmental influences. The probable linkage of development of severe alcohol-induced liver disease with alleles of the HLA-B locus would suggest the influence of a gene(s) on chromosome 6. Such a gene may determine the rate or type of metabolism of alcohol or, since the immune response genes are present on chromosome 6, may indicate genetically controlled variation in the level of the immune and inflammatory response to alcohol-induced changes in liver membrane antigenicity. Further studies are needed to confirm these associations and to determine the type of factor involved.

Selectively reduced hepatic acetaldehyde dehydrogenase in alcoholics.

Acetaldehyde dehydrogenase activity in liver biopsy specimens was considerably lower in 12 non-cirrhotic alcoholics than in 11 control subjects. It is suggested that reduced enzyme activity may cause the impaired metabolism of acetaldehyde reported in alcoholics and may play a part in the pathophysiology of alcoholism. Subcellular fractionation studies showed that acetaldehyde dehydrogenase was localised in the mitochondrial and cytosolic fractions of the liver cell, but in alcoholics the cytosolic component was selectively depleted. This deficiency may be a primary defect in alcoholics, reflecting the genetic aspect of alcoholism.