bluuebunny/crossref_metadata_2025_split huggingface dataset:
RAPID AMMONIUM UPTAKE BY FRESHWATER PHYTOPLANKTON1
Authors: Suttle Curtis A. , Harrison Paul J. 
Published: August 2010

ABSTRACTA natural assemblage of freshwater phytoplankton was removed from an oligotrophic lake and grown at N:P supply ratios of 5:1, 15:1 and 45:1 (by atoms) in semicontinuous culture. After a minimum of 31 days at an average daily growth rate of 0.5 d−1, experiments were conducted examining the time‐course of saturated ammonium uptake rates. Cultures grown under the two lowest N:P supply ratios demonstrated greatly elevated initial, specific uptake rates for ammonium and were able to sequester between 7 and 21% of their daily N requirement in less than 5 min. The initial rates declined rapidly but were followed by a subsequent increase and decrease over a 120 min period.
PRIMARY PRODUCTION OF EDAPHIC ALGAL COMMUNITIES IN A MISSISSIPPI SALT MARSH1
Authors: Sullivan Michael J. , Moncreiff Cynthia A. 
Published: August 2010

ABSTRACTPrimary production rates of edaphic algae associated with the sediments beneath four monospecific canopies of vascular plants were determined over an annual cycle in a Mississippi salt marsh. The edaphic algal flora was dominated by small, motile pennate diatoms. Algal production (as measured by14C uptake) was generally highest in spring‐early summer and lowest in fall. Hourly rates ranged from a low of 1.4 mg C/m2in Juncus roemerianus Scheele to a high of 163 mg C/m2beneath the Scirpus olneyi gray canopy. Stepwise multiple regressions identified a soil moisture index and chlorophyll a as the best environmental predictors of hourly production; light energy reaching the marsh surface and sediment and air temperature proved of little value. Adding the relative abundances of 33 diatom taxa to the set of independent variables only slightly increased R2; however, virtually all variables selected were diatom taxa. R2was only 0.38 for the Spartina alterniflora Loisel. habitat but ranged from 0.70 to 0.87 for the remaining three vascular plant zones. Annual rates of algal production (g C/m2) were estimated as follows: Juncus (28), Spartina (57), Distichlis spicata (L.) Greene (88), and Scirpus (151). The ratio of annual edaphic algal production to vascular plant net aerial production (EAP / VPP) was 10–12% for the first three habitats and 61% for Scirpus. Chlorophyll a concentrations, annual algal production rates, and EAP / VPP values were comparable to those determined in Texas, Delaware, and Massachusetts salt marshes but lower than those reported for Georgia and particularly California marshes.
DIEL CHANGES IN THE COMPOSITION OF PHOTOSYNTHETIC PIGMENTS AND CELLULAR CARBON AND NITROGEN IN CHATTONELLA ANTIQUA (RAPHIDOPHYCEAE)1
Authors: Kohata Kunio , Watanabe Masataka 
Published: August 2010

ABSTRACTAn axenic clonal culture of Chattonella antiqua (Hada) Ono was grown on a 12: 12 h LD cycle in a laboratory culture tank containing 1 m3 of f/2 medium. Diel changes in mean cell volume, cellular carbon (carbon content per cell), C/N ratio, cellular Chl a, Chl a/c ratio and carotenoid composition were observed. Mean cell volume and cellular C, N and pigments increased during the light period as a result of photosynthesis and decreased with increase of cell concentration by phased cell division during the dark period. These changes indicated that carbon assimilation and pigment synthesis occurred together during the light period. However, the patterns of increase were not the same since different diel patterns were also found in the ratios of C/N and chl a/c. Photosynthetic pigments were analyzed by reversed‐phase high‐performance liquid chromatography with ion‐pairing solution. This analysis showed that the dominant carotenoids in C. antiqua were fucoxanthin, violaxanthin and β‐carotene. Diel patterns of Chls a and c were similar to that of fucoxanthin but different from those of violaxanthin and β‐carotene. The cellular contents of Chl a, fucoxanthin and carbon increased in a parallel manner during the light period. On the other hand, the increase of violaxanthin was restricted to only a few hours at the beginning of the light period during cell division cycles.
PHOTOSYNTHETIC PHYSIOLOGY OF PROROCENTRUM MARIAE‐LEBOURIAE (DINOPHYCEAE) DURING ITS SUBPYCNOCLINE TRANSPORT IN CHESAPEAKE BAY1
Authors: Harding Lawrence W. , Coats D. Wayne 
Published: August 2010

ABSTRACTThis paper presents results of field studies on the estuarine dinoflagellate Prorocentrum mariae‐lebouriae (Parke & Ballantine) Faust in Chesapeake Bay. We tested the hypothesis that the photosynthetic physiology of Prorocentrum shows adaptive responses to low‐light during a lengthy subpycnocline transport in estuarine circulation. Prorocentrum underwent a seasonal, northward trnasport between February and June, 1984 and 1985. Low cell densities occurred in the seaward part of the estuary during winter and early‐spring, subpycnocline populations progressed up‐estuary in the ensuring 2–3 months, and dense surface populations developed in the mesohaline portion of the estuary thereafter. We sampled Prorocentrum from surface and subpycnocline waters and measured photosynthesis‐light (P‐I) relations with in situ incubations. The photophysiology of Prorocentrum collected below the pycnoline differed from that of cells in the surface mixed layer in that photosynthetic efficiency, α‐cell−1, was higher, photosynthetic capacity, Pmax‐cell−1 was ·4 times greater for subpycnocline (≦ 10m) samples than for those from the surface mixed layer (≧ 6m). Comparison of in situ photosynthetic properties to those generated in laboratory studies showed that values of α·cell−1 for both surface and subpycnocline samples were in the range found for cultures in low‐light. Concentrations of Chls a, c and peridinin·cell−1 and molar pigment ratios peridinin: Chl a and Chl a: Chl c were not significantly different for the surface and subpycnocline samples, nor were C · cell−1 or C : Chl a. Chloroplast and starch volume fractions and the number of thylakoids were the same for samples collected at different depths, and there was no evidence of cytoplasmic vacuolization in any field samples. These morphometric data for cells from natural populations of Prorocentrum most closely resembled data for laboratory cultures grown at or near 2.6E·m‐−2·4d−1. A lower growth irradiance of 0.3E·m−2·d−1 produced indications of stress in cultures, including starch depletion and vacuolization, that were never observed in natural populations. Based on the combination of these findings, we conclude that Prorocentrum is adapted to low‐light both in the surface mixed layer and beneath the pycnocline, although certain photophysiological characteristics distinguish these two groups of samples.
The Effect of EDTA and ACD on the Recovery and Survival of Cr51‐labelled Blood Platelets
Authors: Abrahamsen Arne Foss 
Published: August 2010

Two anticoagulants, EDTA and ACD, were compared as to their influence on recovery and survival time of in vitro Cr51‐labelled blood plateletsWith EDTA, pronounced trapping of the platelets occurred during the first 24 hours after infusion, due to an in vitro time‐consuming process. With ACD, the trapping was small, and maximum recovery occurred much earlier than with EDTA. Consequently, higher recoveries of infused platelets were obtained with ACD than with EDTA. The survical time was approximately the same with both anticoagulantsDuring progressive storage, survival time and maximum recovery both decreased more rapidly with EDTA than with ACDIt is concluded that ACD causes less damage to platelets than EDTA and is superior for platelet transfusion and labelling.
The Effect of Desferrioxamine on Iron Metabolism in Man
Authors: Hallberg Leif , Hedenberg Lars 
Published: August 2010

The possible use of desferrioxamine (DF) to measure body iron stores necessitated studies on the source of the iron excreted in the urine with the compound. DF did not take significant amounts of iron from transferrin because:(1) DF did not affect the plasma iron turnover(2) The excretion of a transferrin‐bound radioiron tracer was not increased by DF(3) Induced elevation of the plasma iron level was followed only by a slight increase in the iron excretion(4) No effect was observed on the incorporation into red cells of a transferrin‐bound radioiron tracer by DFOther studies indicated that iron, in the stage of being incorporated into red cell precursors, was not a probable source of the iron excreted with DFA significant delay in the excretion of iron with DF was regularly observed and found to be due to a delayed mobilisation of ironFurther studies are necessary to find the source of iron excreted after administration of DF.
Haemorrhagic Thrombocythaemia Due to Defect Platelet Adhesiveness
Authors: Cronberg Stig , Nilsson Inga Marie , Gydell Karl 
Published: August 2010

Platelet adhesiveness was studied in 8 patients with thrombocythaemia with and without bleeding symptoms.Four patients with haemorhagic thrombocythaemia showed prolonged bleeding time and decreased platelet adhesiveness. Four patients with thrombocythaemia but with normal bleeding time, 3 of whom without bleeding symptoms, had normal adhesiveness.
Glucose Metabolism in Normal Erythrocytes II Factors Influencing the Hexokinase Step
Authors: Verdier Carl‐Henric de , Garby Lars 
Published: August 2010

Factors influencing the rate of glucose conversion in red blood cells have been investigated using haemolysates and a purified hexokinase system.The KM‐values for glucose and ATP indicate that the glucose concentrations usually occurring in red blood cells are optimal, whereas variations around the physiological ATP‐concentration will strongly influence the conversion rate.Glucose 6‐phosphate is a potent competitive inhibitor of hexokinase with respect to ATP. Other phosphocompounds tested, fructose 6‐phosphate, fructose 1,6‐diphosphate and 2,3‐diphosphoglycerate, have no inhibitory effect. Inorganic phosphate decreases the inhibition caused by glucose 6‐phosphate. The mechanism for this action is not clear; an interpretation of the data obtained is suggested, however.In intact red blood cells, inosine blocks the phosphorylation of glucosee. The explanation for this effect appears to be the marked increase in glucose 6‐phosphate and the decrease in inorganic phosphate.
Irregular Blood Group Antibodies in 200,000 Individuals
Authors: Kissmeyer‐Nielsen F. 
Published: August 2010

A survey is presented of 4168 sera containing irregular blood‐group antibodies. The antibodies were found during 309,335 antibody screenings and 135,402 cross matchings of blood samples from about 200,000 individuals.About 50 per cent of the antibodies were anti‐D, sometimes together with other antibodies in Rh negatives (D neg), 8 per cent were Rh antibodies in Rh positives (D pos) and many of these antibodies were detectable only by a two‐stage enzyme technique and not by AHG‐technique.Almost 15 per cent of the antibodies belonged to the Lewis‐system. There was a significantly increased number in females of the fertile age, and there was a significant decrease in the number of group O individuals among the Lewis‐immunized persons. The low number of group O individuals indicate a hitherto unrecognized relationship between the ABO‐ and Lewis‐systems.Altogether 2.1 per cent of the individuals described possessed one or more irregular antibodies. The importance is discussed of avoiding complications from these antibodies during blood transfusions. It is concluded that a reliable cross‐match should include a two‐stage enzyme technique as well as the usual saline and AHG tests. It is emphasized that the antibody screening is an efficient prophylactic measure, particularly for smaller hospitals, where complicated cross‐matchings are impractical.
Enhancing Blood Fibrinolytic Activity by a Niacin Compound III. Study of the Activation Mechanism
Authors: AMERY A. , VERMYLEN J. , VERSTRAETE M. 
Published: August 2010

The mechanism of the endogenous activation of the fibrinolytic system in humans by a niacin compound has been investigated.No relation was found between this activation process and changes in the blood glucose level or the oxygen saturation in venous blood. Activation was still possible in reserpine pretreated persons.After a first injection a decrease in leucocytes was noted. After a series of five injections no activation was obtained and no more leucocyte decrease was observed. At this stage normal activation could still be obtained by applying a cuff on the upper arm with a pressure halfway between systolic and diastolic values, suggesting a different activation pathway.
Studies on Hypoxia IV The Differential Haemopoietic Response to Moderate and Severe Hypoxia
Authors: Yoffey J. M. , Smith N. C. W. , Wilson R. S. 
Published: August 2010

Two groups of guinea pigs were subjected to hypoxia at altitude equivalents of 10,000 ft. and 20,000 ft. respectively. Changes in the blood and spleen were observed over a period of 5 days.In the blood there were more and younger reticulocytes at 20,000 ft. than at 10,000 ft. In both groups polycythaemia developed.There was no change in the weight of the spleen at 10,000 ft. but a highly significant increase at 20,000 ft.
Crude or Refined Intrinsic Factor in Preparations for the Oral Treatment of Pernicious Anaemia
Authors: Berlin H. , Berlin R. , Brante G. 
Published: August 2010

A report is given of a comparative study of the absorption of vitamin B12 with the aid of crude or purified intrinsic factor preparations.A crude hog's pylorus material, contained in Hepaforte®, was shown to have an intrinsic factor activity, in relation to its 12 binding capacity, about 40 per cent of that in a purified material used in Bendogen®. No qualitative difference in intrinsic factor activity could be traced for the two materials studied.In pernicious anaemia patients, refractory to standard treatment with vitamin B12 + intrinsic factor, the B12 absorption is generally in the normal range, when the amount of intrinsic factor material given is sufficiently high. Long term clinical trials show, however, that some refractory patients show subnormal serum B12 values even after intrinsic factor doses much higher than those generally recommended. Also in these studies no fundamental difference was found between crude and purified intrinsic factor materials.Oral treatment of pernicious anaemia with vitamin B12 plus intrinsic factor has no place in modern therapy, especially in view of our present knowledge that a daily oral dose of 1 mg vitamin B12 without intrinsic factor gives full protection in all cases of B12 deficiency.
Periodic Thrombocytopenia or Tidal Platelet Dysgenesis in a Man
Authors: ENGSTRÖM K. , LUNDQUIST A. , SÖDERSTRÖM N. 
Published: August 2010

The authors describe the haematologic findings in a man aged 61, who for two years has been under observation with a syndrome of thrombocytopenia, regularly alternating with thrombocytosis of a very regular interval of 39 days. This tidal fluctuation of the platelet counts was within the range 10,000–900,000/μl. There was a synchronous fluctuation of the megakaryocyte numbers in the bone marrow, megakaryocytes being virtually absent in periods of thrombocytopenia. The present condition is by this fact distinct from cyclic thrombotytopenia synchronous with the menstrual cycle in women, in which megakaryocytes are usually plentiful.This case it to all appearences the third one described in the literature of a condition which we would like to labelad interimtidal platelet dysgenesis.
Desferrioxamine‐Induced Urinary Iron Excretion in Normal and Iron‐Deficient Subjects
Authors: Hallberg Leif , Hedenberg Lars 
Published: August 2010

The fraction of intravenously administered desferrioxamine (DF) and radioiron‐labelled ferrioxamine excreted with the urine varied within a narrow range in normal and iron‐deficient subjects. The DF‐induced urinary iron excretion is thus well correlated to the amount of iron chelated in the body.The variation in the amount of iron excreted with the urine after intravenous administration of 10 mg DF/kg body weight was studied in normal and iron‐deficient men and women. The iron excretion was significantly lower in iron‐deficient than in normal subjects, and it was lower in women than in men.The results showed that the iron excretion reflected the iron status of the body.
The Influence of Acute and Long‐Term Exercise on Adenosine Diphosphate‐Induced Platelet Thrombosis and Plasma Lipids in Rats Fed a 40 Per Cent Butter Diet
Authors: Nordöy Arne , Newland Hillery , Hamlin & James T. 
Published: August 2010

The present study was performed in order to determine whether acute or long‐term exercise would influence the tendency to platelet‐thrombosis and the level of the main plasma lipids. Rats given a 40 per cent butter diet for 7 weeks were exposed to acute and long‐term exercise on a treadmill; one group was not exercised. Except for an increase of the free fatty acids in acute exercised rats, no changes were found in total cholesterol, phospholipids, triglycerides and free fatty acids in the plasma. There was no difference in the incidence of ADP‐induced thrombosis among the three groups. Non‐fasting, non‐exercised animals had higher plasma phospholipid and triglyceride levels than fasting, non‐exercised animals. No difference in the incidence of thrombosis was found between fasting and non‐fasting animals.No relation could be established between the incidence of thrombosis and acute or long‐term exercise in the rat. Increase of triglyceride, phospholipid and free fatty acid levels in plasma with more than 100 per cent did not influence the incidence of ADP‐induced thrombosis.
Studies on the Ultrastructure of Pseudopod Formation in Human Blood Platelets.
Authors: Skjørten Fredrik 
Published: August 2010

A method for quantitative evaluation of blood platelet pseudopod formation is presented. Pseudopod formation was studied in whole blood incubated for 0, 5, 10, 20 and 40 minutes at + 4°, + 15° or + 37° C. Samples were anticoagulated with EDTA or sodium citrate, or incubated without anticoagulant. In instantly fixed blood, platelets showed a pseudopod index of about 0.5. In samples incubated at + 4° C., the pseudopod index rose to about 3 after 20 minutes. After 40 minutes there was no further increase. At + 37° C. the pseudopod index did not increase during the first 20 minutes of incubation, but after 40 minutes it had risen to levels almost similar to those of the + 4° samples.EDTA and sodium citrate exerted no influence upon pseudopod formation at any temperature level tested. Mechanical forces operating during the preparation of platelet rich plasma caused pseudopod formation and enhanced temperature induced pseudopod formation.These results support the theory of Bull & Zucker (1965) that blood platelets maintain their lenticular shape by energy requiring processes.
Observations on the Measurement of Platelet Adhesiveness with the Glassbead Column Technique
Authors: Bennett Peter N. 
Published: August 2010

Platelet adhesiveness measured with the glass‐bead column technique was found to be dependent on the age of the glass‐bead columns. Comparison of absolute levels of platelet adhesiveness may therefore not be valid unless columns are matched for age.Increases or decreases in platelet adhesiveness may be compared in columns of the same age irrespective of the absolute levels of adhesiveness.
Platelet Aggregation: an Intermediary Mechanism in Carbon Clearance
Authors: Aken W. G. van , Goote Th. M. , Vreeken J. 
Published: August 2010

The clearance of carbon particles in rabbits is accompanied by aggregation of blood platelets.Substances which influence platelet aggregation (adenosine‐nucleotides) diminish the rate at which carbon is cleared from the blood. The disappearance of carbon particles is accelerated by platelet transfusion.These observations suggest that thrombocyte aggregation is essential for transport of carbon to the Reticulo‐endothelial System.
Studies of Platelet Adhesiveness with Reference to Platelet Age
Authors: Rolovic Zoran , Baldini Mario G. 
Published: August 2010

In this study, autologous human platelets labelled with 31Cr were infused in healthy volunteers and their adhesiveness to glass was repeatedly measured during their survival in the circulation using the Salzman's technique. 51Cr‐specific activity was determined seperately for the ‘adhesive’ and ‘non‐adhesive’ platelets and expressed as a ratio of the two values. This ratio was found to be approximately 1 in all the conditions studied. The results indicated: (1) that platelet labelling in vitro with 51Cr did not alter platelet adhesiveness to glass, and (2) that aging of the platelets in the circulation was not associated with a change in their adhesiveness.Other experiments were done using platelets which had been damaged by a 24hour storage at 4°C. before infusion. The results demonstrated that although survival of these platelets was drastically reduced, their adhesive property to glass remained unchanged. It was concluded that a large ‘reservoir’ of adhesive property must exist in the platelets and that this is independent of the damage produced by cell aging in the circulation and by storage in vitro at 4°C.
Subcellular Particles of Human Platelets
Authors: Day H. James , Holmsen Holm , DR. PHILOS  , Hovig Torstein 
Published: August 2010

ABSTRACTHuman platelet subcellular particles have been fractionated by three methods. The isolated fractions have been examined by electron microscopy and assayed for protein, serotonin, lactate dehydrogenase, cytochrome c oxidase, β‐hydroxybutyrate dehydrogenase, 5′‐nucleotidase, acid phosphatase, β‐glucu‐ronidase, β‐galactosidase, β‐N‐acetylgluco‐saminidase, cathepsin, aryl sulphatase and a‐mannosidase. The latter two enzymes had low activities. Homogenization with blendor caused great solubilization of serotonin and lysosomal enzymes but not cytochrome c oxidase. The granules in the homogenate were swollen and showed great loss of osmo‐philia. The particles were isolated by differential centrifugation and separated into 3 zones after centrifugation on discontinuous sucrose gradients. The upper zone contained proteinaceous material, the second contained mostly vesicular membranes and the lowest one contained α‐granules, transected pseudo‐pods plus mitochondria with varying degrees of preservation. Acid phosphatase was present in the membranes but the highest activity was found in the upper part of the granular band together with β‐galactosidase. β‐Glucuronidase, β‐N‐acetylglucosaminidase and cathepsin were mainly located in the lower part of this band. Homogenization with a ‘no‐clearance’ Teflon pestle caused less solubilization than the blendor and gave better organelle preservation. Isolated particles from such homogenates separated into two bands on gradient centrifugation which morphologically and biochemically were equal to those obtained when these homogenates were applied directly on the gradient. The upper particulate band contained membranes and had bound 5′‐nucleotidase. The lower band possessed in its upper part well‐preserved α‐granules and mitochondria whereas in the lower regions more electron dense granules, often with ‘Bull's eye’, were present. Swollen α‐granules were present mainly in the lower part of this band. All lysosomal enzymes were localized at the same sucrose density. Probably, the α‐gra‐nules are the platelet lysosomes, but with pestle homogenization there was not the biochemical heterogenity as found when using the blendor. With pestle homogenization particle bound serotonin was found in fractions of high sucrose density which contained the dense α‐granules with the ‘Bull's eye’.