bluuebunny/crossref_metadata_2025 huggingface dataset:
ASSOCIATION OF PLEUROCAPSA AND CALOTHRIX (CYANOPHYTA) IN A THERMAL STREAM1,2
Authors: Wickstrom Conrad E. , Castenholz Richard W.
Published: April 2006

A crustose, nodular mat, primarily composed of Calothrix sp. and Pleurocapsa sp., occurs in some alkaline hot springs of the western United States. Together, these species constituted ca. 71% of the mat biomass; the remainder was partitioned between other cyanophytes and bacteria. Their temperature growth ranges in culture were 24–50 C (Calothrix) and 30–55 C (Pleurocapsa). Both clonal cultures had maximal growth rates at 45 C (Pleurocapsa, 1.28 doublings/24 h; Calothrix 2.30). Calothrix grew at approximately twice the rate of Pleurocapsa throughout their coincidental temperature range. The relative proportions of Calothrix (42%) and Pleurocapsa (27%) were constant in a thick mat (ca. 1 mm) regardless of season; however, a thin mat (ca. 0.5 mm) contained significantly more Pleurocapsa (71%) and less Calothrix (5%). Analysis of 10 μm thick microtome sections showed that Pleurocapsa dominated the innermost region (substrate side) of the nodule mat while Calothrix abundance increased from ca. 3% in this region to 80–96% at the surface of thick mat samples (ca. 0.8–2.3 mm). Our proposed that the grazing pressure exerted by an ostracod population accounts for the continued coexistence of and the observed spatial relationships between these species appears most consistent with the observations.
DIFFERENTIATION OF LAMBDA CARRAGEENANS FROM RHODOPHYTA WITH IMMUNOLOGICAL AND SPECTROSCOPIC TECHNIQUES1
Authors: J. Evelegh M. , Vollmer C. M. , McCandless E. L.
Published: April 2006

KCl soluble carrageenans from sporophytes of twoGigartinaspecies were differentiated from those ofChondrus crispusStackhouse,Iridaea cordata(Turner) Bory,Rhodoglossum californicum(J. Ag.) Abbott, and twoPetrocelisspecies by their failure to precipitate on immunodiffusion against either of two absorbed anti‐λ–carrageenan antisera. The carrageenans have been analyzed by infrared spectroscopy, and on this basis it is postulated that the antibody preparations recognize sulphate on C‐6 of the carrageenans. TheGigartinacarrageenans appear to lack sulfate at this position.
STUDIES ON GRACILARIA (GIGARTINALES, RHODOPHYTA): REPRODUCTIVE STRUCTURES1,2,3
Authors: Edelstein T. , Chen L. C. ‐M. , McLachlan J.
Published: April 2006

The reproductive structures of Gracilaria foliifera (Forsk.) Børg. from England and an unnamed species of Gracilaria from Nova Scotia were studied by light microscopy. These two entities are distinguishable on the basis of the type of gonimoblast tissue in their mature cystocarps. This, together with other evidence, suggests that these are separate taxa.
MERCURY AND TEMPERATURE INTERACTIONS ON THE GROWTH RATES OF THREE SPECIES OF FRESHWATER PHYTOPLANKTON1,2
Authors: Knowles Sally C. , Zingmark Richard G.
Published: April 2006

Cultures of freshwater algae, representing three algal divisions, Synura petersenii Korshikov; Chlamydomonas sp.: and Nitzschia sp., were subjected to four different mercury‐temperature shock interactions to demonstrate synergistic effects between mercury and temperature. Algal growth, measured by temporal changes in vivo fluorescence of chlorophyll was used to ascertain the effects. Mercury addition and temperature shock had various inhibitory effects on algal growth. Prior environmental conditions influence the effect of subsequent treatments. Growth of S. petersenii was severely inhibited by mercury in all experiments. Control cultures would not grow at 30 C and died when shacked at this temperature. Chlamydomonas sp. cultures initially inhibited by mercury were able to recover under most conditions after a period of reduced growth. Nitzschia sp. was resistant to mercury except when simultaneously shocked with temperature. Mercury analyses showed that Nitzschia cells at 25 C and 30 C contained a high percentage of the mercury initially added to the cultures. There was a significant loss of mercury at the end of each experiment from all cultures, probably due to volatilization.
ACUTE TOXICITY OF SOME BLUEGREEN ALGAE TO THE PROTOZOAN PARAMECIUM CAUDATUM1
Authors: Ransom Randall E. , Nerad Thomas A. , Meier Peter G.
Published: April 2006

Four species of bluegreen algae were tested for possible effect on the protozoan Paramecium caudatum Ehrenberg. Toxicity was demonstrated using lyophilized cells of Fischerella epiphytica Ghose and Gloeotrichia echinulata (Smith) Richter. Nostoc linckia (Roth) Bornet & Thuret failed to show any effects when lyophilized but became toxic when sonified. Anabaena flos‐aquae (Lyngb.) Bréb. was nontoxic in all tests. G. echinulata was lethal at 0.1 mg·ml−1 which is comparable to the toxic concentration of Aphanizomenon flos‐aquae (L.) Ralfs reported for microcrustaceans.
FATTY ACID DYNAMICS IN THALASSIOSIRA PSEUDONANA (BACILLARIOPHYCEAE): IMPLICATIONS FOR P HYSIOLOGICAL ECOLOGY1,2,3
Authors: Fisher Nicholas S. , Schwarzenbach René P.
Published: April 2006

The growth dry weight, fatty acid weight and fatty acid composition of two clones of Thalassiosira pseudonana Hasle & Heimdal were measured under several growth conditions. Determinations of total cellular fatty acids were made using chemical ionization mass spectrometry. Both clones had the same fatty acids, dominated by C14:0, C16:0, C16:1, C16:3, C16:4, C18:4 and C20:5, though in different relative amounts. Fatty acids typically represented 5–10% the dry weight of a cell during log Phase growth and up to 22% during stationary Phase. The C16 fatty acids of both clones changed as the cultures aged, though much more markedly in the Sargasso Sea done (13–1) than in the estuarine one (3H). The C16:0 and C16:1 acids of both clones declined sharply in the dark and were replenished in the light. Cells maintained in constant illumination, but with no cell division. produced large quantities of these acids. Cells of done 13–1 treated with polychlorinated biphenyl (PCB) initially grew more slowly than control cells, weighed more, and had higher relative amounts of C16:0 and C16:1. Fatty acid studies may provide useful indicators of ecologically important energy reserves and membrane adaptations in the algae.
STICTOCYCLUS STICTODISCUS (BACILLARIOPHYTA): COMMENTS ON ITS ECOLOGY, STRUCTURE AND CLASSIFICATION1,2
Authors: Round Frank E.
Published: April 2006

The rarely studied large diatom Stictocyclus stictodiscus (Grun.) R. Ross has been investigated by light and electron microscopy. Confusion over the classification of this diatom has been reduced, and it has been assigned to a new family, Stictocyclaceae, though the relationship of this to the overall classification of centric diatoms is still not clear.
TRANSLOCATION OF 14C IN MACROCYSTIS INTEGRIFOLIA (PHAEOPHYCEAE)1,2
Authors: Lobban Christopher S.
Published: April 2006

Translocation patterns in the giant kelp, Macrocystis integrifolia Bory, were investigated in situ using 14C tracer; sources and sinks were identified. Export was first detected after 4 h of labeling; experiments were routinely 24 h continuous 14C application. Mature blades exported 14C to young blades on the same frond and on younger fronds, as well as to sporophylls and frond initials at the bases of the fronds. Blades <0.3 m from the apex imported and did not export; this distance did not change seasonally. In spring export from blades 0.3–1.25 m from the apex was exclusively upwards; older blades also exported downwards. In fall downward export began 0.5 m from the apex, and blades >2 m from the apex exported exclusively downwards. Carbon imported by frond initials, young fronds, and sporophylls in fall may partly be stored for growth in early spring. No translocation was seen in very young plants until one blade (secondary frond initial) bad been freed from the apical blade; this blade exported to the apical blade for a time, but imported when it began to develop into a frond. The second and third formed blades on the primary fronds (sporophylls also exported when <0.3 m from the apex, and later stopped. Frond initials and sporophylls on later‐formed fronds did not export at all. The translocation pattern in M. integrifolia differs from that previously reported in M. pyrifera in seasonal change and in distances from the apex at which the changes take place.
PURIFICATION OF RIBULOSE 1,5‐BISPHOSPHATE CARBOXYLASE AND CARBON ISOTOPE FRACTIONATION BY WHOLE CELLS AND CARBOXYLASE FROMCYLINDROTHECASP. (BACILLARIOPHYCEAE.)1,2,3
Authors: Estep Marilyn F. , Tabita F. Robert , Baalen Chase Van
Published: April 2006

Ribulose 1,5‐biphosphate carboxylase has been purified to homogeneity from extracts ofCylindrothecasp. (strain N‐1), a marine, pennate diatom. The carboxylase has a molecular weight and structural composition similar to the enzyme from higher plants. When assayed in the presence of 1 mM NaHCO3the enzyme was stimulated nearly 40% by 1 mM aspartate and over 20% by 1 mM malate, and was inhibited to over 60% by 1 mM phosphoenolpyruvate. Similar experiments, using spinach carboxylase, failed to show activation by these metabolites. When assayed in the presence of 20 mM NaHCO3, 6‐phosphogluconate (1 mM) inhibited activity of ribulose bisphosphate carboxylase from Cylindrothecaby 60%, and higher concentrations of maiate (10 mM) inhibited activity by 25% Carbon isotope fractionation by ribulose bisphosphate carboxylase was ‐32.6% (ppt) when measured under N2using homogeneous enzyme, whereas maximum carbon isotope fractionation by the whole alga grown in 1% ‐C02‐in air averaged ‐ 16.8%. Carbon isotope fractionation by the whole alga varied with the density of the culture and was maximum at a low cell density (1.7 ± 106cellslml). At higher densities, the fractionation decreased by 4.0%. Carbon isotope fractionation has been used previously to determine the pathway of carbon metabolism in other organisms; the results of this investigation seem to indicate that this strain uses both the reductive pentose phosphate pathway and the C4carbon pathway for primary CO2fixation.
EFFECTS OF NITRATE CONCENTRATION ON THE GROWTH AND PHYSIOLOGY OF LAMINARIA SACCHARINA (PHAEOPHYTA) IN CULTURE1,2
Authors: Chapman A. R. O. , Markham J. W. , Lüning K.
Published: April 2006

Laminaria saccharina Lamour. sporophytes were grown in enriched and synthetic media through a range of nitrate concentrations, There was an approximately linear relationship between growth and nutrient concentration up to 10 μ substrate concentration. The half‐saturation constant (K2) was ca. 1.4 μ NO3‐. The internal levels of NO3‐ increased at substrate concentrations above 10 μM b>3‐ and reached levels several thousand times higher than the surrounding medium. Thus there is evidence for luxury consumption of NOsb>3‐. The chlorophyll content and photosynthetic capacities of plants also increased with increasing external NO3‐ The ecological implications of this work are considered.
HYBRIDIZATION OF MACROCYSTIS (PHAEOPHYTA) WITH OTHER FLOAT‐BEARING KELPS1,2
Authors: Sanbonsuga Yoshiaki , Neushul Michael
Published: April 2006

Sporophytes were produced in 22 out of 23 attempts to cross Macrocystia angustifolia Bory with Pelagophycus porra (Lemon) Setchell. Representative samples of these plants were raised in a surge‐tank under greenhouse conditions to several meters in length. The plants resulting from this intergeneric cross were intermediate in morphology between the parental genera. The intermediate plants were similar to those found fry one of the authors (MN) in 1957, and by others since then, in California kelp beds where Macrocystis and Pelagophycus co‐occur, A cross between M. angustifolia and Nereocystis luetkeana (Mertens) P. & R., also produced normal sporophytes. The taxonomic, evolutionary, morphogenetic and genetic implications of these hybridizations are discussed.
CHLOROPLAST STRUCTURAL CHANGES INDUCED BY WHITE LIGHT IN THE MARINE DIATOMSTEPHANOPYXIS TURRIS1,2
Authors: Jeffrey S. W. , Vesk Maret
Published: April 2006

The intensity of white tight used for growingStephanopyxis Turris(Grev.) Ralfs affects the structure of the chloroplasts. In particular, the conformation of the thylakoids, within the bands is altered by increasing the intensity. At low light (100 μW.cm‐2, 12:12 LD cycles) the thylakoids are generally parallel, whereas at 500 μW.cm‐2the thylakoids tend to be twisted and out of plane. The possible significance of these conformational changes is discussed.
UNEXPECTED RESPONSE TO VITAMIN B12OF DOMINANT CENTRIC DIATOMS FROM THE SPRING BLOOM IN THE GULF OF MAINE (NORTHEAST ATLANTIC OCEAN)1,2
Authors: Swift Dorothy G. , Guillard Robert R. L.
Published: April 2006

Twelve clones (seven species) representative of centric diatoms dominant in the spring phytoplankton bloom in the Gulf of Maine were isolated and rendered axenic. Genera included wereThalassiosira, PorosiraandChaetoceros.Unlike most centric diatoms studied previously, none of these has an absolute requirement for vitamin B12.However, B12(5ng.l‐1) stimulated growth of most clones by eliminating or reducing the lag phase and increasing the growth rate. Bloom population densities developed 4–54 days earlier with B12present. Several clones grown with B12removed more than 80% of the vitamin from the medium. When grown in vitamin‐free medium the cells put 0.01–0.7 ng.l‐1B12into the medium. We conclude that vitamin B12is of ecological significance even though the requirement for it is not absolute.
EXCRETION OF GLYCOLATE BY A SPECIES OF CHLORELLA (CHLOROPHYCEAE)1
Authors: Colman Brian
Published: April 2006

The claim that Chlorella sp. (CCAP 211/8p), sometimes referred to as C. fusca, Shihira and Krauss, does not excrete glycolate has been reexamined. Chlorella sp. grown on 5% CO2in air, excreted glycolate when incubated in light in 10 mM bicarbonate. Excretion ceased 30–60 min after transfer of the cells to air and no excretion could be detected with air‐grown cells or with cells grown on 5% CO2in media buffered at pH 8.0. Incubation with 10 mM isonicotinyl hydrazide, a glycolate pathway inhibitor, caused excretion in air‐grown cells and stimulated excretion in CO2‐grown cells indicating that both the rate of glycolate synthesis and metabolism is higher in CO2grown cells than in air‐grown cells. Enhanced glycolate synthesis and excretion in CO2‐grown cells is correlated with law photosynthetic rate in 10 mM bicarbonate, and the photosynthetic rate of these cells doubles over a period of 2–2.5 h after initial transfer from high CO2to bicarbonate. This correlation of photosynthetic induction with cessation of glycolate excretion is similar to that reported in a bluegreen alga and thought to occur in other green algae. These results indicate that glycolate excretion and its regulation in this species of Chlorella is not different from that in other algae.
MITOSIS AND CYTOKINESIS INASTEROMONAS GRACILIS, A WALL‐LESS GREEN MONAD1
Authors: Floyd Gary L.
Published: April 2006

Asteromonas gracilisArtari remains motile throughout cell division. Basal bodies separate and replicate at prophase. They are located lateral to the poles of the closed metaphase spindle. Kinetochores appear at late metaphase. Chromosomes move to the poles and extensions of the nuclear envelope develop into the pyrenoid at anaphase. The interzonal spindle disintegrates at telophase and a diffuse phycoplast is present. Cytokinesis proceeds rapidly from the anterior region of the cell. Newly formed daughter cells have four narrow‐banded rootlets and both distal and proximal fibers connect the basal bodies. Features of cell division inAsteromonasare compared to those in other algae, particularlyDunaliellaandChlamydomonas.
UPTAKE OF INORGANIC NITROGEN BY CODIUM FRAGILE SUBSP. TOMENTOSOIDES (CHLOROPHYTA)1
Authors: Hanisak M. Dennis , Harlin Marilyn M.
Published: April 2006

The uptake of nitrate, nitrite and ammonium by Codium fragile subsp. tomentosoides (van Goor) Silva was measured at different combinations of temperature (6–30 C) and irradiance (0–140 μEin.m‐2. s‐1). Uptake of all three forms of N was greater at 12–24 C than at 6 and 30 C. Although uptake was stimulated by light, saturation occurred at relatively low irradiance (7–28 μEin m‐2 s‐1, depending on the N source and temperature). The Michaelis‐Menten uptake constants (Vmax K)varied with temperature. Vmax was greatest at intermediate temperatures and K was lowest at lower temperatures. The Vmaxfor NH4+ was higher and the K, for NH4+was lower than those for NO3‐‐ and NO2‐‐. Codium was capable of simultaneously taking up all three forms of inorganic N although the presence of NH4+ reduced the uptake of both NO3‐‐ and NO2‐‐. The results of this study indicate that part of the ecological success of Codium in a N‐limited environment may be due to its N uptake capabilities.
FLUCTUATIONS IN FREE AMINO ACID POOLS OFGYMNODINIUM SIMPLEX(DINOPHYCEAE) IN RESPONSE TO AMMONIA PERTURBATION: EVIDENCE FOR GLUTAMINE SYNTHETASE PATHWAY1,2
Authors: Turpin David H. , Harrison Paul J.
Published: April 2006

An ammonia limited chemostat culture ofGymnodinium simplex (Lohm.) Kofoid & Swezy was perturbed with ammonia and fluctuations in the free intracellular amino acid pools were followed 80 min. The steady‐state value of glutamate was 2.07 ± 10‐15mol cell‐1and of glutamine was 0.31 ± 10‐15mol cell‐1. Five minutes after the perturbation, a substantial rise in glutamine was observed with a corresponding decrease in glutamate. This is considered a result of glutamine synthetase acting as the primary ammonia assimilating enzyme. The level of ammonia and the major free amino acids reached a maximum 10 min after the perturbation and then slowly decreased.
NITRATE UPTAKE BY LAMINARIA LONGICRURIS (PHAEOPHYCEAE)1,2
Authors: Harlin Marilyn M. , Craigie J. S.
Published: April 2006

Laminaria longicrucis De la Pylaie took up exogenous nitrate under both summer and winter conditions. During July and August no NO3‐ was detected in the ambient water or in algal tissues although it was present in both in February. Discs (2.3 cm diam.) of thin blade tissue were incubated with NO3‐ at four temperatures, with and without illumination. Similar values Jor NO3‐ uptake were found for both summer and winter collected plants when measured in light at 0 C. An apparent K of 4–6 μM was recorded for both types of plants; the Vmax ranged from 7 to 10 μmol h‐1 g‐1 dry wt measured in ca. 1800 μW cm‐2 of cool‐white fluorescent light. Uptake rates at 5 C were 66%, and at 0 C 30% of those for controls run at 15 C. The alga scavenged NO3‐ from solutions <0.5 μM. Ammonia did not inhibit NO3‐ uptake. Antibiotic pretreatment reduced NO3‐ uptake by a maximum of 12%. Nitrite uptake was inhibited in proportion to the concentration of NO3‐ in the medium.
SPECTROPHOTOMETRICALLY ASSAYED INHIBITORY EFFECTS OF MERCURIC COMPOUNDS ONANABAENA FLOS‐AQUAEANDANACYSTIS NIDULANS(CYANOPHYCEAE)1
Authors: Thomas Dempsey L. , Mantes Joseph G.
Published: April 2006

The growth‐related inhibitory effects of mercuric chloride(MC),methylmercuric chloride (MMC) and phenylmercuric acetate (PMA) (each at 1, 10, 10,2103ppb) were measured inAnabaena flos‐aquae (Lyng.) Bréb. and Anacystis nidulans(Richt.) Drouet&Daily. Optical density changes of control cultures compared against those of experimental cultures showed that MC was the least inhibitory of the compounds. MMC. was the most inhibitory, producing statistically significant inhibition at a concentration as low as I ppb inAnabaena.PMA was more inhibitory than MC but less than MMC. Effects caused by the mercury compounds included bleaching of individual cells, cell size changes and destruction of whole cells; the degree and extent of these effects depended on the compound and its concentration in the nutrient medium. The high sensitivities of the algae tested suggested the possibility of using them as test organisms in bioassays for mercury.
CHRYSOCHROMULINA BREVITURRITA SP. NOV., A NEW FRESHWATER MEMBER OF THE PRYMNESIOPHYCEAE1
Authors: Nicholls Kenneth H.
Published: April 2006

Chrysochromulina breviturrita sp. nov. is described as a new haptonema‐bearing member of the freshwater Prymnesiophyceae. It is ca. three times larger than the only other known freshwater member of the genus (C. parva Lackey)and possesses a haptonema only ca. 0.2–0.3 as long as the haptonema of C. parva. Two equal flagella (1.5–2 as long as the haptonema), a large contractile vacuole, two parietal plasties, a single pyremid, nucleus, Chrysolaminarin‐like droplets and a food vacuole are features readily observed with the light microscope. Dried and shadoweast whole mounts examined with the electron microscope reveal the cell surface covered with two types of small, delicate scales: outer spined scales with a clubshaped terminus and with the spine anchored to a circular to oval base‐plate by 2–6 (7) branching arms; and, spineles oval plate scales with concentric lines and radiating ridges on one face and parallel ridges on the other. C. breviturrita has been found in nine lakes in Ontario (Canada). Pereliminary observations suggest that it is an important component of lake plankton and has probably not been delected in previous work, more because of its fragility than because of its scarcity. Living specimens are a prerequisite for initial identification, since cells frequently rupture and haptonemata are often lost when the organisms are killed with the commonly used fixatives.
PATTERNS OF ALGAL SUCCESSION IN A PERTURBATED MARINE INTERTIDAL COMMUNITY1
Authors: Murray Steven N. , Littler Mark M.
Published: April 2006

Patterns of algal succession for a sewage‐polluted and an unpolluted habitat near Wilson Cove, San Clemente Island, California, were studied from December 1974 to June 1977. Resident populations were analyzed for 56 fully denuded and 34 undisturbed control quadrats during 11 assessment periods. The denuded quadrats in the perturbated (polluted) habitat showed recovery within 1.0 mo as determined by cover, percent similarity and species diversity comparisons with control plots. The short recovery times of the algal populations dominating the perturbated habitat indicate that these species maintain relatively constant overall abundances due to their potential for rapid recruitment and growth. Denuded quadrats in the unpolluted habitat did not show recovery even after 30.0 mo. These quadrats were dominated during the first 1.3 mo by algae characteristic of the perturbated area, including filamentous Ectocarpaceae, colonial diatoms and bluegreen algae. Petalonia fascia (Müll.) Kuntze (1.3–3.0 mo), and Scytosiphon lomentaria (Lyngb.)J. Ag. and Colpomenia sinuosa (Roth) Derb. & Sol. (1.3–5.0 mo) were abundant shortly following plot denudation and provided thick growths that may have excluded other algae. The similarity between the species occupying the sterilized plots during the first few months and those that provide the majority of cover in the perturbated area supports the hypothesis that the dominant algae of the upper and midintertidal regions of this habitat consist largely of early successional or opportunistic species with high capacities for growth and reproduction. Additionally, these experiments suggest that algal populations described for other perturbated epilithic systems also represent resilient subclimax associations.
SURVEY OF SWIMMING POOL ALGAE OF THE PHOENIX, ARIZONA, METROPOLITAN AREA1
Authors: Adamson Richard P. , Sommerfeld Milton R.
Published: April 2006

Thirteen genera of algae were collected and identified from 110 swimming pools in the metropolitan area of Phoenix, Arizona. They included seven cyanophytes (Calothrix, Lyngbya, Oscillatoria, Nostoc, Phormidium, Plectonema, Pleurocapsa), four chlorophytes (Chlamydomonas, Diogenes, Oocystis, Roya), and two chrysophytes (Pleurochloris, Nitzschia). Pleurochloris pyrenoidosa Pascher was the most common swimming pool alga, occurring in 67% of the pools sampled. Species of Phormidium and Plectonema were the next most abundant, with species of Chlorophyta least common, occurring in less than 5% of the swimming pools surveyed. Algae occurred in swimming pools under a wide range of physicochemical conditions. A correlation between physicochemical parameters monitored and the appearance of a particular algal species was not evident.
QUANTITATIVE CHARACTER ANALYSIS FOR A NEW VARIETY OF SYNEDRA CYCLOPUM (BACILLARIOPHYCEAE)1
Authors: Cunningham Gregg A. , Whitson Paul D.
Published: April 2006

Two morphotypes of Synedra cyclopum Brutschy obtained from two depths and time periods at Lake West Okoboji, Iowa, were quantitatively analyzed for value character similarity. Analysis and comparison with earlier collections demonstrate sufficiently stable characters to describe a new variety. A description and Latin diagnosis of the new variety S. cyclopum var. incisa Cunningham is presented.
Effect of Gender on Communication of Health Information to Older Adults
Authors: Dearborn Jennifer L. , Panzer Victoria P. , Burleson Joseph A. , Hornung Frederick E. , Waite Harrison , Into Frances H.
Published: April 2006

OBJECTIVES: To examine the effect of gender on three key elements of communication with elderly individuals: effectiveness of the communication, perceived relevance to the individual, and effect of gender‐stereotyped content.

DESIGN: Survey.

SETTING: University of Connecticut Health Center.

PARTICIPANTS: Thirty‐three subjects (17 female); aged 69 to 91 (mean±standard deviation 82±5.4).

MEASUREMENTS: Older adults listened to 16 brief narratives randomized in order and by the sex of the speaker (Narrator Voice). Effectiveness was measured according to ability to identify key features (Risks), and subjects were asked to rate the relevance (Plausibility). Number of Risks detected and determinations of plausibility were analyzed according to Subject Gender and Narrator Voice. Narratives were written for either sex or included male or female bias (Neutral or Stereotyped).

RESULTS: Female subjects identified a significantly higher number of Risks across all narratives (P=.01). Subjects perceived a significantly higher number of Risks with a female Narrator Voice (P=.03). A significant Voice‐by‐Stereotype interaction was present for female‐stereotyped narratives (P=.009). In narratives rated as Plausible, subjects detected more Risks (P=.02).

CONCLUSION: Subject Gender influenced communication effectiveness. A female speaker resulted in identification of more Risks for subjects of both sexes, particularly for Stereotyped narratives. There was no significant effect of matching Subject Gender and Narrator Voice. This study suggests that the sex of the speaker influences the effectiveness of communication with older adults. These findings should motivate future research into the means by which medical providers can improve communication with their patients.
Genetic Factors and Susceptibility to Falls in Older Women
Authors: Pajala Satu , Era Pertti , Koskenvuo Markku , Kaprio Jaakko , Viljanen Anne , Rantanen Taina
Published: April 2006

OBJECTIVES: To determine whether genetic influences account for individual differences in susceptibility to falls in older women.

DESIGN: Prospective twin cohort study.

SETTING: Research laboratory and residential environment.

PARTICIPANTS: Ninety‐nine monozygotic (MZ) and 114 dizygotic (DZ) female twin pairs aged 63 to 76 from the Finnish Twin Cohort study.

MEASUREMENTS: The participants recorded their falls on a calendar for an average±standard deviation of 344±41 days. Reported falls were verified via telephone interview, and circumstances, causes, and consequences of the fall were asked about.

RESULTS: The total number of falls was 434, of which 188 were injurious; 91 participants had two or more falls. Casewise concordance was 0.61 (95% confidence interval (CI)=0.49–0.72) for MZ twins and 0.49 (95% CI=0.37–0.62) for DZ twins for at least one fall, 0.38 (95% CI=0.23–0.53) for MZ and 0.33 (95% CI=0.17–0.50) for DZ twins for at least one injurious fall, and 0.43 (95% CI=0.26–0.60) for MZ and 0.36 (95% CI=0.17–0.55) for DZ twins for recurrent falls. On average, the proportion of familial influences accounting for the individual differences in susceptibility to at least one fall was 30% and to recurrent falls was 40%; nongenetic familial and nonfamilial factors alone accounted for susceptibility to at least one injurious fall.

CONCLUSION: In community‐dwelling older women, familial factors underlie the risk of falling but not the risk of injurious falls.
Depressive Symptoms in Older People Predict Nursing Home Admission
Authors: Harris Yael , Cooper James K.
Published: April 2006

OBJECTIVES: To evaluate the power of several self‐reported depressive symptoms to predict nursing home admission (NHA).

DESIGN: A Cox proportional hazards model was used to estimate the risk of NHA.

SETTING: Data were from the Health Outcomes Survey (a national random sample of 137,000 Medicare + Choice enrollees aged 65 and older), the Nursing Home Minimum Data Set, and the Medicare Enrollment Database.

PARTICIPANTS: Medicare beneficiaries aged 65 and older enrolled in a Medicare Managed Care Plan who were self‐respondents to the questionnaire and were not institutionalized at the time of the survey.

MEASUREMENTS: Variables were self‐reported functional status, chronic health conditions, demographics, and several mood‐related questions.

RESULTS: After controlling for age, race, sex, marital status, home ownership, functional status, and comorbid conditions, individuals who identified themselves as feeling sad or depressed much of the time over the previous year were at significantly higher risk of NHA.

CONCLUSION: A single question about depressive symptoms can be used to identify individuals at higher risk of NHA. There may be benefit from better screening and treatment of depression in community‐based older people. Depression and social support may be linked. This study was targeted and did not attempt to explain everything that affects NHA. Investigation of the relationship between social support, depression, and NHA should be considered in future research.
Storage of buffy coat–derived platelets in additive solutions: in vitro effects of storage at 4°C
Authors: Sandgren Per , Shanwell Agneta , Gulliksson Hans
Published: April 2006

BACKGROUND:  The aims of this in vitro study were to compare the storage of platelets (PLTs) at 4°C with those stored at 22°C and to determine the in vitro effects of preincubation at 37°C for 1 hour before the analysis on the basis of the maintenance of PLT metabolic and cellular integrity.

STUDY DESIGN AND METHODS:  PLT concentrates (PCs) were prepared from pooled buffy coats (BCs) for paired studies (total eight pools from 160 BCs). Each pool was divided into four PCs and stored under different conditions: at 20 to 24°C on a flatbed agitator, at 20 to 24°C on a flatbed agitator and with incubation of the samples at 37°C for 1 hour before the analysis, at 4°C, and at 4°C and with incubation of the samples at 37°C for 1 hour before the analysis.

RESULTS:  Storage of PLTs at 4°C resulted in reductions in the rate of glycolysis and better retention of pH after Day 10 than in PCs stored at 22°C (Day 14, 7.003 ± 0.047 vs. 7.201 ± 0.146). Hypotonic shock response and extent of shape change were higher at 22°C than at 4°C and in preincubated PCs stored at 22°C than in reference PCs stored at the same temperature (Day 5, 45.6 ± 2.7 vs. 36.5 ± 3.9 and 24.1 ± 2.0 vs. 15.5 ± 1.8). The concentration of RANTES was higher in PCs stored at 22°C than at 4°C (Day 7, 179 ± 25 vs. 79 ± 32).

CONCLUSION:  PLTs stored at 4°C without agitation maintain metabolic and cellular characteristics to a great extent during 21 days of storage. These studies confirm the view that PLTs lose their discoid shape and that this loss with storage at 4°C is associated with reductions in metabolic rate and in their release of α‐granule content.
A national sample of US paternity tests: do demographics predict test outcomes?
Authors: Bishai David , Astone Nan , Argys Laura , Gutendorf Robert , Filidoro Chris
Published: April 2006

BACKGROUND:  Nearly 300,000 paternity tests are performed in the United States annually to include or exclude a male as the biological father of a child. Little is known about how well the test outcomes could be predicted simply on the basis of the subjects’ social background. Our objective is to document the demographic composition of test subjects and to determine how well ethnic background and age predict paternity inclusion.

STUDY DESIGN AND METHODS:  A national database of 9999 paternity test results was formed weighted to represent the population of paternity establishment cases for the United States. Multiple regression determined the odds ratio of a paternity inclusion based on demographic variables such as race and age.

RESULTS:  The test results indicated paternity inclusions in 72 percent of cases, overall. The percent included varied little across racial and/or ethnic categories with a low of 67 percent in African Americans and a high of 82 percent among Native Americans, but these differences were not significant in multivariate analysis. The likelihood of inclusion showed a modest but significant correlation with increased maternal age. Mothers of European origin who nominated non‐Europeans as fathers were less likely to identify the correct man as father.

CONCLUSION:  For any subject receiving a genetic test in a child support office, predicting a 72 percent probability that the test will show paternity inclusion offers as good an estimate of the test outcome as a subgroup estimate based on a subject’s age, race, and child characteristics.
A Randomized Clinical Trial of Continuous Flow Nitrous Oxide and Nalbuphine Infusion for Sedation of Patients During Radiofrequency Atrial Flutter Ablation
Authors: LAURENT GABRIEL , BERTAUX GÉRALDINE , MARTEL ALEXANDRA , FRAISON MICHEL , FROMENTIN STÉPHANE , GONZALEZ STÉPHANIE , PIERRE FRANÇOIS SAINT , WOLF JEAN ERIC
Published: April 2006

Background: In patients with common atrial flutter (CAF), radiofrequency ablation (RFA) causes discomfort. Patients undergoing RFA often feel pain which is difficult to control as the mechanisms are unclear.

Hypothesis: Inhaled nitrous oxide (N2O) is a potent sedative‐analgesic‐anxiolytic agent that may relieve anxiety and discomfort during CAF ablation.

Methods and Results: In a prospective randomized study, the effect of Inhaled N2O was compared with that of intravenous sedation with Nalbuphine during CAF ablation in 76 patients (64 ± 13 years, 56 men). We used a 24 pole mapping catheter around the tricuspid annulus and a 8‐mm tip ablation catheter for each patient. Forty‐two patients (group 1) underwent radiofrequency (RF) application to the cavotricuspid isthmus 5 minutes after the beginning of inhalation of a (50% N2O/50% O2) mixture. Thirty‐four patients (group 2), underwent the first RF application 15 minutes after the end of an infusion of Nalbuphine (20 mg delivered over 15 minutes). Ablation‐related anxiety and discomfort were assessed using a visual analog scale (VAS) ranging from 0 to 100 mm, with 0 correlating to the statement “no pain at all” and 100 with “the worst possible pain.” The VAS score was determined at the end of each application.The number of RF applications (group 1; 10 ± 8 vs group 2; 11 ± 6, P = NS) and procedure duration (group 1; 75 ± 53 minutes vs group 2; 72 ± 45 minutes, P = NS), were similar for the two groups. N2O sedation compared with nalbuphine infusion reduced VAS for anxiety (10 mm ± 8 vs 58 mm ± 22, P < 0.05) and for discomfort (18 mm ± 9 vs 45 mm ± 34, P < 0.01), respectively. Although there was more frequent vomiting in group 1; 7 of 42 (17%) than in group 2; 3 of 34 (9%), P < 0.05, patients were less likely to have hypotension during the procedure 1 of 42 (2.5%) versus 4 of 34 (12%), P < 0.05, respectively.

Conclusion: Inhalation of a (50% N2O/50% O2) mixture during RF ablation for atrial flutter is a safe and efficient way to reduce anxiety and discomfort caused by RF applications.
Excitation of the Intrinsic Conduction System Through His and Interventricular Septal Pacing
Authors: LASKE TIMOTHY G , SKADSBERG NICHOLAS D , HILL ALEXANDER J , KLEIN GEORGE J , IAIZZO PAUL A
Published: April 2006

Background: Direct His bundle pacing results in rapid synchronous ventricular activation. However, clinical experiences with such pacing have been associated with long procedure times and compromised pacing and sensing performance.

Methods: We evaluated myocardial activation sequences (AS) for pacing of the His bundle and peri‐His region and assessed acute pacing performance using custom‐designed plunge electrodes. Unipolar pacing was performed in isolated swine hearts (n = 10) using four quadripolar stimulation/sensing electrodes implanted into the interventricular septum and equally spaced between the membranous septum and the coronary sinus ostium (zones 1–4, respectively; electrode depth (ED) 1 = most distal, ED 4 = most proximal). Optimal pacing sites were defined as: pacing thresholds ≤1.5 V, a P‐R ratio of ≤0.5, and ≥50% occurrence of an intrinsic midseptal left ventricular (LV) endocardial electrical breakout (BO) and activation pattern.

Results: Pacing thresholds improved with greater depth of electrode location within the septum (ED 1: 1.51 ± 0.8 V vs ED 4: 5.2 ± 3.8 V, P < 0.001), as did the P‐R ratio (0.34 ± 0.6 vs 0.78 ± 1.0, P < 0.05). His potentials were only observed in zone 1 and 2 electrodes (0.12 and 0.02 mV, respectively). Only electrodes in zones 1 and 2 produced LV endocardial electrical BOs in the midseptal region that demonstrated an intrinsic‐like endocardial AS. Depth 1 and 2 electrodes (11.75 and 8.75 mm, respectively) in zone 1 satisfied all three optimal pacing site requirements.

Conclusions: This study has shown that LV activation patterns similar to sinus rhythm may be achieved without direct activation of the His bundle, while maintaining acceptable pacing and sensing performance. These data indicate that pacing systems designed to stimulate the tissues below the point at which the His bundle penetrates the central fibrous body may provide improved system efficiency and LV performance in comparison to both direct His bundle pacing and traditional pacing sites.
Reduction of RV Pacing by Continuous Optimization of the AV Interval
Authors: MILASINOVIC GORAN , SPERZEL JOHANNES , SMITH TIMOTHY W. , MEAD HARDWIN , BRANDT JOHAN , HAISTY WESLEY K. , BAILEY J. RUSSELL , ROELKE MARC , SIMONSON JAY , GERRITSE BART , ENGLUND JENNIFER , COMPTON STEVEN J. ,   on Behalf of The Worldwide EnPulse Investigators )
Published: April 2006

Background: In patients requiring permanent pacing, preservation of intrinsic ventricular activation is preferred whenever possible. The Search AV+ (SAV+) algorithm in Medtronic EnPulse™ dual‐chamber pacemakers can increase atrioventricular (AV) intervals to 320 ms in patients with intact or intermittent AV conduction. This prospective, multicenter study compared the percentage of ventricular pacing with and without AV interval extension.

Methods: Among 197 patients enrolled in the study, the percentage of ventricular‐paced beats was evaluated via device diagnostics at the 1‐month follow‐up. Patient cohorts were defined by clinician assessment of conduction via a 1:1 AV conduction test at the 2‐week follow‐up. The observed percentage of ventricular pacing with SAV + ON and the predicted percentage of ventricular pacing with SAV + OFF were determined from the SAV + histogram data for the period between the 2‐week and 1‐month follow‐up visits.

Results: Of 197 patients, 110 (55.8%) had intact 1:1 AV conduction, of which 109 had 1‐month data. SAV + remained ON in 99/109 patients; 10 patients had intrinsic A‐V conduction intervals beyond SAV + nominal and therefore SAV + disabled. The mean percentage of ventricular pacing in the 109 patients was SAV+ ON = 23.1% (median 3.7%) versus SAV + OFF = 97.2% (median 99.7%). In 87 patients without 1:1 AV conduction, SAV + was programmed OFF in 6, automatically disabled in 52, and remained ON in 29. In 8 of these patients, 80–100% reduction in ventricular pacing was observed with SAV + ON.

Conclusion: The Search AV+ algorithm in the EnPulse pacemaker effectively promotes intrinsic ventricular activation and substantially reduces unnecessary ventricular pacing.
Back to the Future: The Role of the Autonomic Nervous System in Atrial Fibrillation
Authors: CHEN JAY , WASMUND STEPHEN L. , HAMDAN MOHAMED H.
Published: April 2006

The purpose of this manuscript is to review the current literature regarding the role of the autonomic nervous system (ANS) in atrial fibrillation (AF). We will be reviewing its effect on initiation, maintenance, and termination of AF, with emphasis on the role of baroreflex gain (BRG) and autonomic reflexes in the maintenance of this arrhythmia. While it is generally accepted that the ANS plays an important role in AF, the extent of that role remains controversial. Much of the controversy could be explained by the time frame during which the autonomic measurements were made, the differences in patient population, and possibly the differential effect of the autonomic changes on the trigger versus the substrate. While vagal stimulation results in shortening of the atrial effective refractory period and increased dispersion of refractoriness, its effect on the “trigger” might be antiarrhythmic. During AF, cardiac filling pressure increases while arterial blood pressure decreases sending conflicting messages to the medulla. The acute effect is an increase in sympathetic activity to ensure adequate hemodynamic stability. On the other hand, the long‐term effects might be impairment in the cardiopulmonary BRG and changes that accentuate the presence of AF. While radiofrequency ablation has provided us with a unique insight into the role of possible denervation in AF suppression, the exact mechanisms involved are far from being completely understood. Today, in an era where great technological advances have occurred, our need to understand the role of the ANS in AF is greater than ever.
Left Ventricular Lead Stabilization Utilizing a Coronary Stent
Authors: CESARIO DAVID A. , SHENODA MICHAEL , BRAR RAMANDEEP , SHIVKUMAR KALYANAM
Published: April 2006

Cardiac resynchronization therapy has been recently demonstrated to have a mortality and morbidity benefit in heart failure (HF) patients with cardiac dyssynchrony. Currently, the most widely used method of left ventricular (LV) lead placement involves transvenous placement of leads via the coronary sinus (CS) and into a tributary branch. Lead dislodgement is a common cause for reoperation, and continues to be a common problem despite advances in equipment and operator techniques. We describe a case where a coronary stent was placed in a lateral branch of the CS to stabilize the lead against the vessel wall.
T‐Wave Oversensing by an Implantable Cardioverter Defibrillator after Successful Ablation of Idiopathic Ventricular Fibrillation
Authors: STROHMER BERNHARD , SCHERNTHANER CHRISTIANA , PICHLER MAXIMILIAN
Published: April 2006

Focal ablation of trigger premature ventricular complexes (PVCs) from the Purkinje system helped to suppress idiopathic ventricular fibrillation (VF) in an athlete who had suffered from frequent appropriate shock therapies. However, only a few days after successful ablation T‐wave oversensing occurred during exercise and resulted in repetitive distressing defibrillator shocks. Despite lack of any changes on the surface ECG, the endocardially recorded electrogram revealed an unfavorable ratio of R‐to‐T‐wave amplitude predisposing to double counting with accelerated heart rates. This case illustrates that T‐wave oversensing may complicate the clinical course after successful ablation of malignant Purkinje ectopy.
Laser Recanalization of the Subclavian Vein
Authors: HENRIKSON CHARLES A. , ALEXANDER DIANA , RINGEL RICHARD E. , BRINKER JEFFERY A.
Published: April 2006

We report the use of a long wire and introducer as a rail for the laser recanalization of a chronically occluded subclavian vein following extraction of a fractured permanent pacing lead. This allowed new pacing leads to be placed through the previously occluded vessel.
New Approximations to the Malthusian Parameter
Authors: Ridout M. S. , Cole D. J. , Morgan B. J. T. , Byrne L. J. , Tuite M. F.
Published: April 2006

Summary Approximations to the Malthusian parameter of an age‐dependent branching process are obtained in terms of the moments of the lifetime distribution, by exploiting a link with renewal theory. In several examples, the new approximations are more accurate than those currently in use, even when based on only the first two moments. The new approximations are extended to include a form of asymmetric cell division that occurs in some species of yeast. When used for inference, the new approximations are shown to have high efficiency.
Development of molecular diagnostic markers for sharpshooters Homalodisca coagulata and Homalodisca liturata for use in predator gut content examinations
Authors: De León Jesse H. , Fournier Valerie , Hagler James R. , Daane Kent M.
Published: April 2006

To aid in identifying key predators of Proconiini sharpshooter species present in California, we developed and tested molecular diagnostic markers for the glassy‐winged sharpshooter, Homalodisca coagulata (Say), and smoke‐tree sharpshooter, Homalodisca liturata (Ball) (Homoptera: Cicadellidae). Two different types of markers were compared, those targeting single‐copy sequence characterized amplified regions (SCAR) and mitochondrial markers targeting the multicopy cytochrome oxidase subunit genes I (COI) and II (COII). A total of six markers were developed, two SCAR and four mitochondrial COI or COII markers. Specificity assays demonstrated that SCAR marker HcF5/HcR7 was H. coagulata specific and HcF6/HcR9 was H. coagulata/H. liturata specific. COI (HcCOI‐F/R) and COII (HcCOII‐F4/R4) markers were H. coagulata specific, COII (G/S‐COII‐F/R) marker was H. coagulata/H. liturata specific, and lastly, COII marker (Hl‐COII‐F/R) was H. liturata specific. Sensitivity assays using genomic DNA showed the COI marker to be the most sensitive marker with a detection limit of 6 pg of DNA. This marker was 66‐fold more sensitive than marker Hl‐COII‐F/R that showed a detection limit of 400 pg of DNA. In addition, the COI marker was 4.2‐fold more sensitive than the COII marker. In predator gut assays, the COI and COII markers demonstrated significantly higher detection efficiency than the SCAR markers. Furthermore, the COI marker demonstrated slightly higher detection efficiency over the COII marker. Lastly, we describe the inclusion of an internal control (28S amplification) for predation studies performing predator gut analyses utilizing the polymerase chain reaction (PCR). This control was critical in order to monitor reactions for PCR failures, PCR inhibitors, and for the presence of DNA.
Pheromone‐binding protein and general odorant‐binding protein of Sesamia nonagrioides: sex‐ and diel‐dependent expression
Authors: Konstantopoulou M.A. , Pratsinis H. , Kletsas D. , Mazomenos B.E.
Published: April 2006

The expression of a pheromone‐binding protein (PBP) and a general odorant‐binding protein (GOBP) in Sesamia nonagrioides (Lef.) (Lepidoptera: Noctuidae) was studied. Lymantria dispar's PBP1 antibody yielded an immunoreactive band with an apparent MW of approximately 14.8 kDa, present specifically in the antennae of both sexes, with males having approximately three‐fold the quantity found in females. Furthermore, Manduca sexta's odorant‐binding protein‐2 (GOBP2) antibody recognized a band at approximately 14.5 kDa in the antennae of both sexes. Levels of both proteins were compared between scotophase and photophase periods in insects that were raised under L16:D8 or under constant light. The level of GOPB2 was significantly lower in both sexes during photophase and continuous light; whereas the level of the PBP was significantly lower in females’ antennae, in males’ antennae it remained at the same level as that found during the scotophase.