bluuebunny/crossref_metadata_2025 huggingface dataset:
ULTRASTRUCTURAL STUDIES ON BIGELOWIELLA NATANS, GEN. ET SP. NOV., A CHLORARACHNIOPHYTE FLAGELLATE
Authors: Moestrup Øjvind , Sengco Mario
Published: March 2003

Three isolates from the Provasoli‐Guillard National Center for Culture of Marine Phytoplankton at Bigelow Laboratory, previously labeled Pedinomonas sp. and Pedinomonas minutissima from the green algal class Pedinophyceae, have been examined by light microscopy and TEM and shown to belong to the Chlorarachniophyceae, a class of nucleomorph‐containing amebae. The three isolates represent the first chlorarachniophycean flagellates to be discovered. The ultrastructure of the cells has been examined in detail, with particular emphasis on the flagellar apparatus, a feature not examined in detail in chlorarachniophytes before. Cells are basically biflagellate, but the second flagellum is represented by a very short basal body only. Flagellar replication has shown this flagellum to be the mature stage, that is, the no. 1 flagellum, whereas the long emergent flagellum is the no. 2 flagellum that shortens into a short basal body during cell division. Mitosis is open with a pair of centrioles at each pole. Emergent flagella are absent during mitosis. Cells may form cysts, and the flagellar basal bodies and part of the flagellar roots are maintained in the cysts. Four microtubular roots emanate from the basal bodies, and the path of one of them is very unusual and very unlike any other known flagellate. No striated roots were observed. Other fine‐structural features of the cell include a very unusual type of pyrenoid and a special type of extrusome. Cells are mixotrophic. The three isolates are very similar and are described as Bigelowiella natans, gen. et sp. nov. Ultrastructurally, chlorarachniophytes do not show close relationship to any known group of algae or other protists.
PHOTOACCLIMATION OF PHOTOSYNTHESIS IRRADIANCE RESPONSE CURVES AND PHOTOSYNTHETIC PIGMENTS IN MICROALGAE AND CYANOBACTERIA1
Authors: MacIntyre Hugh L. , Kana Todd M. , Anning Tracy , Geider Richard J.
Published: March 2003

The photosynthesis‐irradiance response (PE) curve, in which mass‐specific photosynthetic rates are plotted versus irradiance, is commonly used to characterize photoacclimation. The interpretation of PE curves depends critically on the currency in which mass is expressed. Normalizing the light‐limited rate to chl a yields the chl a‐specific initial slope (αchl). This is proportional to the light absorption coefficient (achl), the proportionality factor being the photon efficiency of photosynthesis (φm). Thus, αchl is the product of achl and φm. In microalgae αchl typically shows little (<20%) phenotypic variability because declines of φm under conditions of high‐light stress are accompanied by increases of achl. The variation of αchl among species is dominated by changes in achl due to differences in pigment complement and pigment packaging. In contrast to the microalgae, αchl declines as irradiance increases in the cyanobacteria where phycobiliproteins dominate light absorption because of plasticity in the phycobiliprotein:chl a ratio. By definition, light‐saturated photosynthesis (Pm) is limited by a factor other than the rate of light absorption. Normalizing Pm to organic carbon concentration to obtain PmC allows a direct comparison with growth rates. Within species, PmC is independent of growth irradiance. Among species, PmC covaries with the resource‐saturated growth rate. The chl a:C ratio is a key physiological variable because the appropriate currencies for normalizing light‐limited and light‐saturated photosynthetic rates are, respectively, chl a and carbon. Typically, chl a:C is reduced to about 40% of its maximum value at an irradiance that supports 50% of the species‐specific maximum growth rate and light‐harvesting accessory pigments show similar or greater declines. In the steady state, this down‐regulation of pigment content prevents microalgae and cyanobacteria from maximizing photosynthetic rates throughout the light‐limited region for growth. The reason for down‐regulation of light harvesting, and therefore loss of potential photosynthetic gain at moderately limiting irradiances, is unknown. However, it is clear that maximizing the rate of photosynthetic carbon assimilation is not the only criterion governing photoacclimation.
MUCILAGINOUS CAPSULE ADSORPTION AND INTRACELLULAR UPTAKE OF COPPER BY KIRCHNERIELLA APERTA (CHLOROCOCCALES)1
Authors: Lombardi Ana T. , Vieira Armando A. H. , Sartori Luiz A.
Published: March 2003

The purpose of the present investigation was to evaluate possible ecological and physiological functions of mucilaginous capsules produced by the freshwater algae Kirchneriella aperta Teiling (Chlorococcales) as related to copper ions. All experiments were performed using synthetic media under laboratory‐controlled conditions. Copper interactions were investigated by distinguishing between adsorption onto the mucilaginous material present at the surface of the cells, intracellular uptake, and differentiation between total dissolved copper and free copper ions in the culture medium. Kirchneriella aperta is sensitive to copper, as revealed by a 96‐h EC50 value of 10−9.22 M Cu2+. We demonstrated that the mucilaginous capsules were able to sequester copper ions from the medium through a passive mechanism, thus providing the cell with a mechanism able to postpone the toxic effects of copper. The organic material that diffuses into the test medium as well as the mucilaginous capsules produced by K. aperta both effectively complex copper; thus, toxicity must be related to free copper ions and not the total dissolved copper concentration in the medium.
WINTER PHYTOPLANKTON BLOOMS UNDER ICE ASSOCIATED WITH ELEVATED OXYGEN LEVELS1
Authors: Phillips Karen A. , Fawley Marvin W.
Published: March 2003

Many shallow lakes in north temperate zones experience reduced dissolved oxygen concentration under ice. However, some shallow lakes display supersaturated dissolved oxygen concentrations (>20 mg·L−1) in late winter under conditions of maximum ice thickness. During the winters of 1996, 1997, and 1999, we collected phytoplankton samples from Arrowwood Lake near Pingree, North Dakota to determine whether a specific alga was involved in dissolved oxygen supersaturation in this lake. Although dissolved oxygen supersaturation was not observed during this period, we did observe an increase in dissolved oxygen concentration that was associated with a phytoplankton bloom during late February and early March in both 1996 and 1997. In 1996, the bloom was composed of the dinoflagellate, Peridinium aciculiferum (Lemm.) Lemm. and several species of cryptomonads. A similar bloom of P. aciculiferum was followed by a bloom of several species of euglenoids in 1997. In contrast, P. aciculiferum was only a minor component of the winter phytoplankton, dissolved oxygen concentrations remained low, and no bloom event was observed in 1999. Statistical analyses indicated a significant relationship (rs = 0.57, P = 0.019) between dissolved oxygen levels and the density of the dinoflagellate, P. aciculiferum, but no significant relationship between dissolved oxygen levels and densities of other phytoplankton. These results suggest that the elevated levels of dissolved oxygen are associated with the dinoflagellate, P. aciculiferum. This bloom was most likely the result of an excystment event rather than a general growth response.
RELATIONSHIPS BETWEEN LITTORAL DIATOMS AND THEIR CHEMICAL ENVIRONMENT IN NORTHEASTERN GERMAN LAKES AND RIVERS1
Authors: Schönfelder Ilka , Gelbrecht Jörg , Schönfelder Jörg , Steinberg Christian E. W.
Published: March 2003

We explored statistical relationships between the composition of littoral diatom assemblages and 21 chemical and physical environmental variables in 69 lakes and 15 river sites in the lowland of northeastern Germany. Canonical correspondence analysis with single treatment and with forward selection of environmental variables was used to detect 11 important ecological variables (dissolved inorganic carbon [DIC], Na+, total phosphorus [TP], dissolved organic carbon [DOC], total nitrogen [TN], pH, oxygen saturation, dissolved iron, SO42−, NH4+, soluble reactive silicium) and maximum water depth or Ca2+ or soluble reactive phosphorus that most independently explain major proportions of the total diatom variance among the habitats. Monte Carlo permutation tests showed that each contributed a significant additional proportion (P < 0.05) of the variance in species composition. Together, these 11 most important environmental variables explained 34% of the total variance in species composition among the sites and captured 73% of the explained variance from the full 21 parameters model. Weighted‐averaging regression and calibration of 304 indicator taxa with tolerance down‐weighting and classic deshrinking was used to develop transfer functions between littoral diatoms and DIC, pH, TP, TN, and Cl−. The DOC:TP ratio was introduced and a weighted‐averaging model was developed to infer allochthonous DOC effects in freshwater ecosystems. This diatom‐DOC/TP model was significant (P < 0.001) and explained 7.6% of the total diatom variance among the sites, surpassing the inferential power of the diatom‐TP‐transfer function (7.3% explained variance). The root‐mean‐square errors of prediction of the models were estimated by jack‐knifing and were comparable with published data sets from surface sediment diatom samples. The data set of littoral diatoms and environmental variables allows use of the diatom‐environmental transfer functions in biomonitoring and paleolimnological approaches across a broad array of natural water resources (such as floodplains, flushed lakes, estuaries, shallow lakes) in the central European lowland ecoregion.
THE IMPORTANCE OF DIATOM CELL SIZE IN COMMUNITY ANALYSIS1
Authors: Snoeijs Pauli , Busse Svenja , Potapova Marina
Published: March 2003

The large variation in size and shape in diatoms is shown by morphometric measurements of 515 benthic and pelagic diatom species from the Baltic Sea area. The largest mean cell dimension (mostly the apical axis) varied between 4.2 and 653 μm, cell surface area between 55 and 344,000 μm2, and cell volume between 21 and 14.2 × 106μm3. The shape‐related index, length to width ratio, was between 1.0 and 63.3 and the shape‐ and size‐related index, surface area to volume ratio, was between 0.02 and 3.13. Diatom community analysis by multivariate statistics is usually based on counts of a fixed number of diatom valves with species scores irrespective of cell size. This procedure underestimates the large species for two reasons. First, the importance of a species with higher cell volume is usually larger in a community. Second, larger species usually have lower abundances and their occurrence in the diatom counts is stochastic. This article shows that co‐occurring small and large diatom species can respond very differently to environmental constraints. Large epiphytic diatoms responded most to macroalgal host species and small epiphytic diatoms most to environmental conditions at the sampling site. Large epilithic diatoms responded strongly to salinity, whereas small epilithic diatoms did so less clearly. The conclusion is that different scale‐dependent responses are possible within one data set. The results from the test data also show that important ecological information from diatom data can be missed when the large species are neglected or underestimated.
CELL CYCLE DEPENDENT VIRUS PRODUCTION IN MARINE PHYTOPLANKTON1
Authors: Thyrhaug Runar , Larsen Aud , Brussaard Corina P. D. , Bratbak Gunnar
Published: March 2003

In this study we investigated virus production in two marine phytoplankton species and how it relates to the host's cell cycle. Phaeocystis pouchetii (Hariot) Lagerheim and Pyramimonas orientalis McFadden, Hill & Wetherby, growing synchronously in batch cultures, were infected with their respective viruses (PpV and PoV) at four different stages in the cell cycle and the production of free virus was then measured for 30 h. The virus production in P. orientalis infected with PoV depended on the time of infection, whereas no such relation was found for P. pouchetii infected with PpV. The P. orientalis cultures infected at the end of the dark period and at the beginning of the light period produced three times more virus than those infected in the middle of the light period and eight times more virus than those infected at the beginning of the dark period. The latent periods for PpV and PoV were 12–14 h and 18–20 h, respectively, and in both cases were independent of the host cell cycle. The differences in virus production may be attributed to light or cell cycle dependent regulation of host infection, metabolism, or burst size. Regardless of the mechanism, these differences may be related to differences in the ecological strategies of the hosts and their ability to form blooms.
RESPONSE TO SALINITY AND HEAT STRESS IN TWO HALOTOLERANT CHLOROPHYTE ALGAE1
Authors: Henley William J. , Major Kelly M. , Hironaka Janice L.
Published: March 2003

Two new isolates of halotolerant chlorophyte algae from the Salt Plains National Wildlife Refuge in Oklahoma, USA, tentatively identified as Dunaliella sp. Teodoresco and Nannochloris sp. Naumann, were characterized with respect to interaction between growth salinity and short‐term heat tolerance. Cells were cultured at 23–25° C over a wide range of salinity. In both species, salinity alone had little effect on maximum photochemical yield (measured by pulse modulated fluorescence) and integrity of the light harvesting system (77 K fluorescence emission spectra). In contrast, Nannochloris exhibited decreasing growth rate (μ), light‐saturated photosynthetic capacity (Pcellmax), respiration (Rd), light‐harvesting efficiency (αcell), and chl content with increasing salinity. Cultures were heated for 2 h near their upper temperature limits (41.5° C for Dunaliella and 45° C for Nannochloris grown at 50 psu). Dunaliella was progressively more heat‐tolerant with increasing salinity. Photochemical yield of cells at 100 and 50 psu was inhibited by about 15% and 40%, respectively, and largely recovered within 30 min after return to 23° C. Thermal inhibition of photochemical yield in Nannochloris was about 45% at both 50 and 100 psu, but recovery was slower at 100 psu. At 20 psu, both species were almost 90% inhibited by high temperature and required more than a day to recover. In both species, 2 h of heating increased the PSI:PSII fluorescence emission ratio (714:690 nm) at all salinities. This ratio largely recovered within 24 h in Dunaliella at 50 and 100 psu and partially recovered in Nannochloris at 100 psu, but cells of both species heated at 20 psu were chlorotic the next day.
UNCOUPLING OF SILICON COMPARED WITH CARBON AND NITROGEN METABOLISMS AND THE ROLE OF THE CELL CYCLE IN CONTINUOUS CULTURES OFTHALASSIOSIRA PSEUDONANA(BACILLARIOPHYCEAE) UNDER LIGHT, NITROGEN, AND PHOSPHORUS CONTROL1
Authors: Claquin Pascal , Martin‐Jézéquel Véronique , Kromkamp Jacco C. , Veldhuis Marcel J. W. , Kraay Gijsbert W.
Published: March 2003

The elemental composition and the cell cycle stages of the marine diatomThalassiosira pseudonanaHasle and Heimdal were studied in continuous cultures over a range of different light‐ (E), nitrogen‐ (N), and phosphorus‐ (P) limited growth rates. In all growth conditions investigated, the decrease in the growth rate was linked with a higher relative contribution of the G2+M phase. The other phases of the cell cycle, G1 and S, showed different patterns, depending on the type of limitation. All experiments showed a highly significant increase in the amount of biogenic silica per cell and per cell surface with decreasing growth rates. At low growth rates, the G2+M elongation allowed an increase of the silicification of the cells. This pattern could be explained by the major uptake of silicon during the G2+M phase and by the independence of this process on the requirements of the other elements. This was illustrated by the elemental ratios Si/C and Si/N that increased from 2‐ to 6‐fold, depending of the type of limitation, whereas the C/N ratio decreased by 10% (E limitation) or increased by 50% (P limitation). The variations of the ratios clearly demonstrate the uncoupling of the Si metabolism compared with the C and N metabolisms. This uncoupling enabled us to explain that in any of the growth condition investigated, the silicification of the cells increased at low growth rates, whereas carbon and nitrogen cellular content are differently regulated, depending of the growth conditions.
A CHLOROPHYLL FLUORESCENCE INDEX TO ESTIMATE SHORT‐TERM RATES OF PHOTOSYNTHESIS BY INTERTIDAL MICROPHYTOBENTHOS1
Authors: Serôdio João
Published: March 2003

An index based on chl a fluorescence quenching analysis was tested as a predictor of photosynthetic rates of undisturbed intertidal microphytobenthic assemblages. The fluorescence index, Pfluo, was derived from the combination of different chl a fluorescence parameters chosen to represent the two main sources of short‐term variability in the community‐level microphytobenthic photosynthesis: 1) the quantum yield of photosynthesis of the microalgae present in the photic zone of the sediment, φP, and 2) the community‐level efficiency of photosynthetic light absorption, ɛ, determined by the microalgal concentration in the photic zone. Variations in φP were traced by the fluorescence index ΔF/Fm′ (the effective quantum yield of charge separation at PSII), whereas changes in ɛ were followed by the fluorescence parameter Fo (dark or minimum fluorescence level). Gross photosynthetic rate, P, and fluorescence parameters were measured nondestructively and simultaneously under in situ conditions, on the same samples, using oxygen microelectrodes and pulse amplitude modulation fluorometry, respectively. Despite the large and uncorrelated hourly variability in irradiance, photosynthetic rate, and fluorescence parameters included in Pfluo, highly significant correlations between Pfluo and P were found for all the sampling periods, encompassing hourly, biweekly, and seasonal time scales. The variability in P explained by Pfluo ranged from 84.3% to 91.4% when sampling periods were considered separately and reached 81.1% when all data were pooled. The results of the study show that despite its simplicity, the index Pfluo can be used to trace short‐term variations in the photosynthetic rate of undisturbed microphytobenthic assemblages undergoing rhythmic vertical migration.
RECRUITMENT OF MICROCYSTIS (CYANOPHYCEAE) FROM LAKE SEDIMENTS: THE IMPORTANCE OF LITTORAL INOCULA1
Authors: Brunberg Anna‐Kristina , Blomqvist Peter
Published: March 2003

Recruitment of Microcystis from sediments to the water column was investigated in shallow (1–2 m) and deep (6–7 m) areas of Lake Limmaren, central Sweden. Recruitment traps attached to the bottom were sampled on a weekly basis throughout the summer season (  June–September). A comparison between the two sites showed that the recruitment from the shallow bay was significantly higher over the entire season for all three Microcystis species present in the lake. Maximum rates of recruitment were found in August, when 2.3 × 105 colonies m−2·day−1 left the sediments of the shallow area. Calculated over the entire summer, Microcystis colonies corresponding to 50% of the initial abundance in the surface sediments were recruited in the shallow bay, whereas recruitment from the deep area was only 8% of the sediment colonies. From these results we conclude that shallow areas, which to a large extent have been overlooked in studies of recruitment of phytoplankton, may be crucial to the dynamics of these organisms by playing an important role as inoculation sites for pelagic populations.
Systematics of Coccoid Green Algae: Morphology vs. 18S rRNA Gene Phylogeny
Authors: Krienitz L. , Wolf M. , Hegewald E. , Hepperle D.
Published: March 2003

Classical approaches using morphological characters for the circumscription of taxa in coccoid green algae do not adequately reflect the phylogenetic relationships. Phylogenetic trees based on 18S rRNA gene sequence analysis provide new insights into the systematics of these algae. We give a review and discuss the content of orders of coccoid green algae and evaluate the usefulness of some traditionally used diacritic features. Whereas the content of the orders Chlorococcales and Chlorellales needs to be reduced, the order Sphaeropleales comprises more families than in the traditional circumscription. According to molecular biological investigations the Neochloridaceae, Selenastraceae and Scenedesmaceae formerly classified in the Chlorococcales and later into the Chlorellales belong to the Sphaeropleales. The Hydrodictyaceae, formerly a member of the Protosiphonales, are also to be grouped in the Sphaeropleales. Some members of the Ulotrichales, which propagate by binary fission (e.g. Nannochloris and Catena) cluster together with autosporine coccoid taxa within the Trebouxiophyceae. With the example of members of the Selenastraceae, Oocystaceae and Chlorellacea it is shown that the morphology of cells as well as the formation of coenobia, spines, mucilage and incrustations cannot be used to separate genera.
A Traffic Sign Recognition Test Can Discriminate Between Older Drivers Who Have and Have Not Had a Motor Vehicle Crash
Authors: MacGregor Jan M. , Freeman Daniel H. , Zhang Dong
Published: March 2003

OBJECTIVES:To determine whether a Traffic Sign Recognition Test (TSRT) can identify older drivers who recently had a motor vehicle crash (MVC).

DESIGN:Retrospective, matched, case‐control study.

SETTING:Licensed drivers in Galveston, Texas.

PARTICIPANTS:60 crash and 60 control subjects matched for age and gender. Cases were identified from accident records. Controls were selected from a randomized list of licensed drivers in Galveston.

MEASUREMENTS:Folstein Mini‐Mental State Examination (MMSE) and the TSRT.

RESULTS:A TSRT significantly distinguished between case and control groups (P= .01). The MMSE did not (P= .61). A TSRT predicted MVC in a multivariate analysis controlling for education, MMSE score, race/ethnicity, and mileage driven/year (odds ratio = 0.88, 95% confidence interval = 0.77–1.00).

CONCLUSION:A TSRT successfully identifies older drivers with a recent MVC, but the test lacks sensitivity and specificity. A prospective study is needed to further delineate the TSRT's usefulness in predicting crash risk in older drivers.
Dementia and Race: Are There Differences Between African Americans and Caucasians?
Authors: Miles Toni P. , Froehlich Tanya E. , Bogardus Sidney T. , Inouye Sharon K.
Published: March 2003

This study provides an overview of racial differences in etiology and prevalence of dementia. Preliminary findings indicate that the clinical and molecular etiologies of dementia differ between races. African Americans have a higher prevalence of vascular dementia and a lower prevalence of Parkinsonian dementia than do Caucasians. The genetic etiologies of Alzheimer's‐type dementia appear to differ between African Americans and Caucasians. The variations in dementia etiologies and in cognitive testing accuracy between races suggests the urgent need to develop racially appropriate cognitive assessment methods and to develop preventive and treatment etiologies differently according to racial background of individual patients.
Dependence in Activities of Daily Living and Cognitive Impairment Strongly Predicted Mortality in Older Urban Residents in Brazil: A 2‐Year Follow‐Up
Authors: Ramos Luiz R. , Simoes Eduardo J. , Albert Marilyn S.
Published: March 2003

OBJECTIVES:

To identify a set of predictors of mortality among residents in the community, before any physical, biochemical, or image examination is performed, that could be collected on a routine standardized basis, to help the clinician define a patient follow‐up strategy and the health planner make decisions regarding the care of older people.

DESIGN:

A household follow‐up study, with an evaluation at baseline and 2 years later.

SETTING:

Residential area, with a low rate of in‐ and outmigration, in Sao Paulo, a large industrialized urban center in southeastern Brazil.

PARTICIPANTS:

One thousand six hundred sixty‐seven older urban residents in the community (65+), from different socioeconomic backgrounds, enrolled after a study area census.

INTERVENTION:

Structured home interview with Brazilian Older Americans Resources and Services Multidimensional Functional Assessment Questionnaire, previously validated in Portuguese.

MEASUREMENTS:

A logistic regression model for the risk of dying in the period was developed, having as independent variables, sociodemographic characteristics plus six other dimensions: subjective self‐evaluation of health, past medical history, use of health services, dependence in activities of daily living (ADLs), mental health, and cognitive status.

RESULTS:

There were 146 deaths (9%) in the cohort during the follow‐up interval. The variables that appeared as independent predictors of death in the final logistic regression model were: gender (relative risk (RR) = 2.8 (males)), age (RR = 2.0 (80+ vs. 65–69)), hospitalization in the previous 6 months (RR = 2.4 (at least one)), dependence in ADLs (RR = 3.0 (assistance required for 7 vs. 0 ADLs)); and cognitive impairment (RR = 1.9 (Mini‐Mental State Examination 18 vs. 30)).

CONCLUSION:

These findings suggest that in developing countries such as Brazil, an assessment of dependence in daily living and cognitive status should be an essential part of any health evaluation of an older person, not only because these variables represent potentially high independent mortality risks, but also because they can be easily and reliably assessed, using well‐validated instruments, and may be susceptible to intervention. J Am Geriatr Soc 49:1168–1175, 2001.
The Vulnerable Elders Survey: A Tool for Identifying Vulnerable Older People in the Community
Authors: Saliba Debra , Elliott Marc , Rubenstein Laurence Z. , Solomon David H. , Young Roy T. , Kamberg Caren J. , Carol Roth RN , MacLean Catherine H. , Shekelle Paul G. , Sloss Elizabeth M. , Wenger Neil S.
Published: March 2003

OBJECTIVES: To develop a simple method for identifying community‐dwelling vulnerable older people, defined as persons age 65 and older at increased risk of death or functional decline. To assess whether self‐reported diagnoses and conditions add predictive ability to a function‐based survey.

DESIGN: Analysis of longitudinal survey data.

SETTING: A nationally representative community‐based survey.

PARTICIPANTS: Six thousand two hundred five Medicare beneficiaries age 65 and older.

MEASUREMENTS: Bivariate and multivariate analyses of the Medicare Current Beneficiary Survey; development and comparison of scoring systems that use age, function, and self‐reported diagnoses to predict future death and functional decline.

RESULTS: A multivariate model using function, self‐rated health, and age to predict death or functional decline was only slightly improved when self‐reported diagnoses and conditions were included as predictors and was significantly better than a model using age plus self‐reported diagnoses alone. These analyses provide the basis for a 13‐item function‐based scoring system that considers age, self‐rated health, limitation in physical function, and functional disabilities. A score of ≥3 targeted 32% of this nationally representative sample as vulnerable. This targeted group had 4.2 times the risk of death or functional decline over a 2‐year period compared with those with scores <3. The receiver operating characteristics curve had an area of .78. An alternative scoring system that included self‐reported diagnoses did not substantially improve predictive ability when compared with a function‐based scoring system.

CONCLUSIONS: A function‐based targeting system effectively and efficiently identifies older people at risk of functional decline and death. Self‐reported diagnoses and conditions, when added to the system, do not enhance predictive ability. The function‐based targeting system relies on self‐report and is easily transported across care settings.
Preventing Injuries in Older People by Preventing Falls: A Meta‐Analysis of Individual‐Level Data
Authors: Robertson M. Clare , Campbell A. John , Gardner Melinda M. , Devlin Nancy
Published: March 2003

OBJECTIVES: Our falls prevention research group has conducted four controlled trials of a home exercise program to prevent falls in older people. The objectives of this meta‐analysis of these trials were to estimate the overall effect of the exercise program on the numbers of falls and fall‐related injuries and to identify subgroups that would benefit most from the program.

DESIGN: We pooled individual‐level data from the four trials to investigate the effect of the program in those aged 80 and older, in those with a previous fall, and in men and women.

SETTING: Nine cities and towns in New Zealand.

PARTICIPANTS: One thousand sixteen community dwelling women and men aged 65 to 97.

INTERVENTION: A program of muscle strengthening and balance retraining exercises designed specifically to prevent falls and individually prescribed and delivered at home by trained health professionals.

MEASUREMENTS: Main outcomes were number of falls and number of injuries resulting from falls during the trials.

RESULTS: The overall effect of the program was to reduce the number of falls and the number of fall‐related injuries by 35% (incidence rate ratio (IRR) = 0.65, 95% confidence interval (CI) = 0.57–0.75; and, respectively IRR = 0.65, 95% CI = 0.53–0.81.) In injury prevention, participants aged 80 and older benefited significantly more from the program than those aged 65 to 79. The program was equally effective in reducing fall rates in those with and without a previous fall, but participants reporting a fall in the previous year had a higher fall rate (IRR = 2.34, 95% CI = 1.64–3.34). The program was equally effective in men and women.

CONCLUSION: This exercise program was most effective in reducing fall‐related injuries in those aged 80 and older and resulted in a higher absolute reduction in injurious falls when offered to those with a history of a previous fall.
Deaths Between Bedrails and Air Pressure Mattresses
Authors: Miles Steven H.
Published: March 2003

OBJECTIVES: To describe how patients die by becoming trapped between therapeutic air pressure mattresses and bed rails.

DESIGN: A retrospective review of all voluntary reports deaths in beds with air mattresses that can be found in the Food and Drug Administration's on‐line databases of adverse medical events that cover 1994 to 2001.

SETTING: Death reports come from manufacturers, medical staff, and coroners and describe deaths in hospitals, nursing homes, and home care, although type of care site is often not given.

MEASUREMENTS: Event descriptions were reviewed to determine how the person became entrapped in the rail and how responsibility for the event was allocated.

RESULTS: There were 35 deaths involving many product lines. Twenty‐one deaths involved overlay air mattresses placed on top of a regular mattress. Thirteen patients died in beds with built‐in air mattresses. Compression of the mattress allowed an off‐center person to slide against the rail where reexpansion of the mattress kept the person compressed against the rail. Two patterns were seen. In one, the mattress bunched up behind a person who was lying on the side of the bed, pushing the neck against a bedrail. In the second type, a patient died after sliding off the bed and having the neck or chest compressed between the rail and bed. Manufacturers attributed the deaths to poor clinical decision‐making or inadequate monitoring.

CONCLUSIONS: Lethal asphyxiation in beds with air pressure mattresses is a variant of bedrail‐mattress entrapment that requires redesign by bed manufacturers and risk awareness by clinicians.
Handgrip Strength and Mortality in Older Mexican Americans
Authors: Al Snih Soham , Markides Kyriakos S. , Ray Laura , Ostir Glenn V. , Goodwin James S.
Published: March 2003

OBJECTIVES: To examine the association between handgrip strength and mortality in older Mexican American men and women.

DESIGN: A 5‐year prospective cohort study.

SETTING: Five southwestern states: Texas, New Mexico, Colorado, Arizona, and California.

PARTICIPANTS: A population‐based sample of 2,488 noninstitutionalized Mexican‐American men and women aged 65 and older.

MEASUREMENTS: Maximal handgrip strength, timed walk, and body mass index were assessed at baseline during 1993/94. Self‐reports of functional disability, various medical conditions, and status at follow‐up were obtained.

RESULTS: Of the baseline sample with complete data, 507 persons were confirmed deceased 5 years later. Average handgrip strength ± standard deviation was significantly higher in men (28.4 kg ± 9.5) than in women (18.2 kg ± 6.5). Of men who had a handgrip strength less than 22.01 kg and women who had a handgrip strength less than 14 kg, 38.2% and 41.5%, respectively, were dead 5 years later. In men in the lowest handgrip strength quartile, the hazard ratio of death was 2.10 (95% confidence interval (CI) = 1.31–3.38) compared with those in the highest handgrip strength quartile, after controlling for sociodemographic variables, functional disability, timed walk, medical conditions, body mass index, and smoking status at baseline. In women in the lowest handgrip strength quartile, the hazard ratio of death was 1.76 (95% CI = 1.05–2.93) compared with those in the highest handgrip strength quartile. Poorer performance in the timed walk and the presence of diabetes mellitus, hypertension, and cancer were also significant predictors of mortality 5 years later.

CONCLUSION: Handgrip strength is a strong predictor of mortality in older Mexican Americans, after controlling for relevant risk factors.
The Effect of Cardiovascular and Osteoarticular Diseases on Disability in Older Italian Men and Women: Rationale, Design, and Sample Characteristics of the Progetto Veneto Anziani (PRO.V.A.) Study
Authors: Corti Maria‐Chiara , Guralnik Jack M. , Sartori Leonardo , Baggio Giovannella , Manzato Enzo , Pezzotti Patrizio , Barbato GianMaria , Zambon Sabina , Ferrucci Luigi , Minervini Sergio , Musacchio Estella , Crepaldi Gaetano
Published: March 2003

OBJECTIVES: Describe the methodology and preliminary results of the Progetto Veneto Anziani (PRO.V.A.) Study, an observational study of the Italian population aged 65 and older

DESIGN: Cross‐sectional cohort observation.

SETTING: Northern Italy.

PARTICIPANTS: Italians aged 65 and older, living in both the community and nursing homes.

MEASUREMENTS: At baseline, participants were interviewed at their homes and subsequently examined by nurses and physicians at the two study clinics using an extensive battery of clinical, instrumental, biochemical, and physical performance tests. Hand, knee, hip, and chest x‐rays and bone densitometry were performed in 92% of the participants, and 99% of the participants consented to blood drawing and deoxyribonucleic acid analyses. The physician who performed the physical examination determined disease presence based on several components of the interview and examination. A further, comprehensive determination was performed with standardized algorithms using all the information collected on each participant, including hospital records surveillance, standardized x‐ray readings, and blood assays. In one of the study sites, a brain magnetic resonance imaging was performed in a subsample of the participants (820 persons).

RESULTS: Overall response rate to the baseline clinic visit was 77% for men and 64% for women. Co‐presence of at least one cardiovascular disease (CVD) and at least one osteoarticular disease (OAD) was identified in 10%, 22%, and 29% of men and 9%, 24%, and 40% of women aged 65 to 74, 75 to 84, and 85 and older, respectively. Overall, the mean number of coexisting chronic conditions was 1.8 for men and 2.4 for women.

CONCLUSIONS: The PRO.V.A. study has the potential to provide an original contribution to clarify the mechanisms whereby diseases cause disability in older men and women; the particular focus on CVD and OADs will make it possible to comprehensively evaluate the development of disability as it relates to these two important conditions.
Physical Activity as a Determinant of Change in Mobility Performance: The Longitudinal Aging Study Amsterdam
Authors: Visser Marjolein , Pluijm Saskia M. F. , Stel Vianda S. , Bosscher Ruud J. , Deeg Dorly J. H.
Published: March 2003

OBJECTIVES: This study examined the association of (change in) physical activity and decline in mobility performance in older men and women.

DESIGN: A 3‐year prospective study using data of the Longitudinal Aging Study.

SETTING: Netherlands.

PARTICIPANTS: Two thousand one hundred nine men and women aged 55 to 85.

MEASUREMENTS: Total physical activity (expressed as hours per day and kilocalories per day) and sports participation were measured using a validated, interviewer‐administered questionnaire. Mobility performance was assessed using two timed tests: 6‐meter walk and repeated chair stands.

RESULTS: Mobility performance declined for 45.6% of the sample. At baseline, the mean time ± standard deviation spent on total physical activity was 3.0 ± 2.1 h/d or 719 ± 543 kcal/d, and 56.6% of the sample participated in sports. Sports participation and a higher level of total physical activity, walking, or household activity were associated with a smaller mobility decline. After 3 years, total physical activity declined, and only 53.4% of those reporting sports at baseline continued doing so. Continuation of physical activity over time was associated with the smallest decline in mobility. The observed associations were similar for those with and without chronic disease (P> 0.3). The conclusions did not change after adjustment for potential confounders, including demographic and lifestyle variables, depression, and cognitive status.

CONCLUSIONS: Physical activity, and especially a regularly active lifestyle, may slow the decline in mobility performance. A beneficial effect was observed for sports and nonsports activities, independent of the presence of chronic disease.
Is There a Relationship Between Fat‐Free Soft Tissue Mass and Low Cognitive Function? Results From a Study of 7,105 Women
Authors: Nourhashémi Fati , Andrieu Sandrine , Gillette‐Guyonnet Sophie , Reynish Emma , Albarède Jean‐Louis , Grandjean Hélène , Vellas Bruno
Published: March 2003

OBJECTIVES: To test the hypothesis that low fat‐free soft tissue mass and cognitive impairment are independently associated.

DESIGN: Cross‐sectional study.

SETTING: Five geographic areas of France.

PARTICIPANTS: Seven thousand one hundred five community‐dwelling women aged 75 and older recruited from electoral rolls between 1992 and 1994.

MEASUREMENTS: Fat‐free soft tissue mass, body fat mass, and bone mineral density were measured using dual‐energy x‐ray absorptiometry. Study participants were assessed for cognitive impairment using the Short Portable Mental Status Questionnaire and divided into two groups according to their scores. Logistic regression models were used to calculate multivariate‐adjusted differences in body composition between two groups of subjects according to their cognitive function.

RESULTS: After adjustment for confounders, compared with women in the highest quartile of fat‐free soft tissue mass, women in the lowest quartile had an odds ratio of 1.43 (95% confidence interval (CI) = 1.07–1.91) for cognitive impairment. Low fat mass was also associated with lower cognitive function, with an odds ratio of 1.35 (95% CI = 1.01–1.79) for the lower quartile of fat mass compared with the highest quartile. There was no association between cognitive impairment and bone mineral density.

CONCLUSIONS: This finding supports the hypothesis that low muscle mass is associated with cognitive impairment in older women. These two components represent major causes of frailty and functional decline in older people and could have some common mechanisms. Nevertheless, these results do not predict the causal variable.
Use of Lipid‐Lowering Drugs in Older Adults With and Without Dementia: A Community‐Based Epidemiological Study
Authors: Rodriguez Eric G. , Dodge Hiroko H. , Birzescu Maria A. , Stoehr Gary P. , Ganguli Mary
Published: March 2003

OBJECTIVES: To compare the use of lipid‐lowering drugs in community‐dwelling older adults with and without dementia.

DESIGN: Comparison of lipid‐lowering drug use by demented cases and nondemented controls based on secondary analysis of data from a longitudinal epidemiologic study.

SETTING: Longitudinal study of a largely rural, low‐ socioeconomic‐status, community‐based cohort of older persons residing in the mid‐Monongahela Valley of South‐west Pennsylvania (the Monongahela Valley Independent Elders Survey).

PARTICIPANTS: Eight hundred forty‐five individuals of mean ± standard deviation (SD) age of 80.5 ± 4.6, participating in the fifth biennial wave of data collection.

MEASUREMENTS: Demographics; medical history; medication regimen (including examination of prescription bottle labels); self‐report of most recent visit to primary care physician (PCP); and standardized clinical assessment to determine presence of dementia, including Clinical Dementia Rating (CDR).

RESULTS: One hundred seventy participants (20.1% of total subject cohort) had dementia, with a CDR of 0.5 or greater. Mean ages of demented and nondemented individuals were 83.5 ± 5.1 and 79.8 ± 4.2, respectively. Similar proportions, 87.7% and 89.5%, of these groups reported PCP visits in the previous year. Of the total sample, 9.4% (3.5% of the demented and 10.8% of the nondemented) were taking lipid‐lowering drugs. After adjustment for age, sex, education, visit with PCP within the past year, and potential confounding clinical and lifestyle variables (self‐reported heart disease, stroke or transient ischemic attacks, hypertension, smoking, and alcohol consumption), dementia was associated with a lower likelihood of taking a lipid‐lowering drug (odds ratio = 0.39, 95% confidence interval = 0.16–0.95). In post hoc subgroup analyses, similar results were found when restricting lipid‐lowering drugs to statins alone but were not statistically significant. Drug use was not associated with severity of dementia (CDR = 0.5 vs CDR ≥ 1).

CONCLUSIONS: Demented individuals were less likely than their nondemented counterparts to be taking lipid‐lowering drugs. This finding could reflect different prescribing patterns by physicians for demented and nondemented patients or a possible protective effect of these drugs against dementia.
Modified fluid gelatin in leukapheresis accumulation and persistence in the body
Authors: ROCK G. , WISE P. , KARDISH R. , HUESTIS D. W.
Published: March 2003

Current methods for centrifuged granulocyte procurement involve the use of an agent to produce red cell rouleaux and enhance separation of leukocytes. Hydroxyethyl starch (HES), the agent most frequently used, has the disadvantage of causing progressive volume expansion and persisting in the circulation for long periods. We therefore assessed modified fluid gelatin (MFG) as a possible replacement for HES during granulocyte collection. We found that MFG is cleared more rapidly from the circulation with no traces remaining 7 days after multiple exposure, as determined by hydroxyproline measurement. However, after four consecutive daily infusions, we measured 0.60 liters plasma expansion in four individuals tested, somewhat lower than the 0.85 liters previously reported for HES. Modified fluid gelatin causes no impairment of coagulation with normal prothrombin time (PT), partial thromboplastin time (PTT), and platelet function.
Five‐day storage of platelet concentrates
Authors: Rock G. , Sherring V.A. , Tittleyx P.
Published: March 2003

The short 72‐hour shelf‐life of platelet concentrates stored in standard PL146 (Fenwal) plastic bags often results in shortages of platelets. This 3‐day limitation is based on the biochemical and physiological changes that occur during storage and that result in decreased viability and survival after transfusion. We assessed both in vitro and in vivo function of platelet concentrates stored for 3 and 5 days in two new plastic packs: PL732 (Fenwal) and CLX (Cutter). The concentrate pH was maintained above 7.0 in both bags and there was little change in platelet count or size following 5 days of storage. Aggregation response to adenosine diphosphate, epinephrine, and collagen was maintained well. The PCO2 values indicated good gas escape with lower values after 5 days of storage than at 0 time. Lactate accumulation and glucose utilization were also lower in these new bags. Autologous survivals of chromium‐labeled platelets stored for 5 days were 6.0 days (PL732) and 5.1 days (CLX), which are equal to or better than those found for platelets stored for 3 days in PL146. Posttransfusion increments in thrombocytopenic patients were acceptable; 49 percent after 1 hour and 31 percent after 24 hours for concentrates stored in CLX and 44 percent after 1 hour and 28 percent after 24 hours for concentrates stored in PL732. Both of these new bags, which contain different types of plasticizers, provide an environment that results in an improved product and will permit 5‐day storage of platelet concentrates; these two benefits will help to alleviate the difficulties in supply of platelet concentrates.
Intensive plasma exchange therapy in ten patients with idiopathic thrombocytopenic purpura
Authors: Blanchette V.S. , Hogan V.A. , McCombie N.E. , Drouin J. , Bormanis J.D. , Taylor R. , Rock G.A.
Published: March 2003

Intensive plasma exchange therapy with fresh‐frozen plasma as the replacement fluid was used to manage ten patients, five with acute and five with chronic immune thrombocytopenic purpura (ITP). Therapy was started because of severe hemorrhage (1 case), failure to respond to steroid therapy (6 cases), or steroid dependence (3 cases). After a median of four exchanges over 6 days (median total volume removed, 11.7 liters), initial responses, defined as a platelet count greater than 100,000 per µl at the end of the exchange series, were observed in 80 percent of the patients treated. Two adolescents, ages 16 and 17 years, with chronic ITP failed to respond to plasma exchange therapy and subsequently responded to splenectomy. Prolonged remissions of 9 months and greater than 2 years were observed in two patients with acute ITP; in patients with chronic ITP, no prolonged remissions occurred. Neither pre‐exchange levels of platelet‐associated immunoglobulin G (PAIgG) nor circulating immune complexes predicted the response to plasma exchange, although serially determined PAIgG levels correlated with the severity of ITP and response, or lack of response, to plasma exchange. We conclude that intensive plasma exchange merits further study in patients with acute ITP unresponsive to steroid therapy to determine if the need for splenectomy is reduced. In selected patients with chronic ITP, exchange therapy may provide short‐term adjunctive benefit.
Platelet production planning to ensure availability while minimizing outdating
Authors: Ledman R. E. , Groh N.
Published: March 2003

Steps were undertaken to reduce platelet concentrate outdating while maintaining the ability to provide them to hospitals as needed. A brief daily information exchange was established with the purpose of determining a platelet concentrate production goal for each weekday. This procedure has resulted in the ability to meet 100 percent of the hospital demand while reducing platelet concentrate outdating from greater than 20 percent to 2.95 percent over a 6‐month period. When considering the 4 months when all platelet concentrates had 5‐day expiration dates, the outdating rate was 2.57 percent. The significant reduction in outdating brought about by our procedure can result in substantial economic savings for a regional blood supplier.