bluuebunny/crossref_metadata_2025 huggingface dataset:
Pyramimonas tychotreta, sp. nov. (prasinophyceae), a new marine species from antarctica: light and electron microscopy of the motile stage and notes on growth rates
Authors: Daugbjerg Niels
Published: March 2003

An undescribed marine prasinophyte, Pyramimonas tychotreta, sp. nov., was isolated from a water sample collected near the ice edge in the Weddell Sea (Antarctica) and is characterized by means of light and electron microscopy. This is the second described Antarctic species in the genus and it possesses a cell ultrastructure typical for members of the subgenus Vestigifera McFadden. The quadriflagellated cells measure 8–12 μm in length and 6–7 μm in width and are equipped with seven types of organic scales that cover the flagella and cell body. The scale floor of the box scales is ornamented by quadrants of parallel striations running perpendicular to one another. The scale floor is further characterized by a number of randomly positioned perforations. The wall of the box scales may be solid or possess up to five perforations. The base of the crown scales is square with rounded corners. It is formed of two crossed ribs, the extremities of which are interconnected by a peripheral rib. Four upright arms, attached to the peripheral rib in positions slightly offset from its junction with the cross ribs, join up with the distal extremity of a central upright strut. Each arm possesses two spines. The limuloid scales are cross‐striped by 10–12 ribs. Some details of the flagellar apparatus are briefly reported. Pyramimonas tychotreta is compared with other species of the genus. Experiments were conducted to study the response of growth rate to variations in temperature and salinity in the clonal culture. The best growth rate (0.45 divisions·24 h−1) was found at 4.6° C; growth ceased at temperatures in excess of 12° C. Growth in salinities ranging from 15 to 35 psu was similar, but was arrested at 10 psu. These studies suggest that P. tychotreta as a cold stenotherm and euryhaline taxon. New observations are presented on the geographic distribution of previously described species of Pyramimonas Schmarda from the Northern Foxe Basin, Canada.
ORGANIZATION OF THE nif GENES OF THE NONHETEROCYSTOUS CYANOBACTERIUM TRICHODESMIUM SP. IMS101
Authors: Dominic Benny , Zani Sabino , Chen Yi‐Bu , Mellon Mark T. , Zehr Jonathan P.
Published: March 2003

An approximately 16‐kb fragment of the Trichodesmium sp. IMS101 (a nonheterocystous filamentous cyanobacterium) “conventional”nif gene cluster was cloned and sequenced. The gene organization of the Trichodesmium and Anabaena variabilis vegetative (nif 2) nitrogenase gene clusters spanning the region from nif B to nif W are similar except for the absence of two open reading frames (ORF3 and ORF1) in Trichodesmium. The Trichodesmium nif EN genes encode a fused Nif EN polypeptide that does not appear to be processed into individual Nif E and Nif N polypeptides. Fused nif EN genes were previously found in the A. variabilis nif 2 genes, but we have found that fused nif EN genes are widespread in the nonheterocystous cyanobacteria. Although the gene organization of the nonheterocystous filamentous Trichodesmium nif gene cluster is very similar to that of the A. variabilis vegetative nif 2 gene cluster, phylogenetic analysis of nif sequences do not support close relatedness of Trichodesmium and A. variabilis vegetative (nif 2) nitrogenase genes.
ISOLATION AND CHARACTERIZATION OF PARAMYLON SYNTHASE FROM EUGLENA GRACILIS (EUGLENOPHYCEAE)1,
Authors: Bäumer Dietrich , Preisfeld Angelika , Ruppel Hans Georg
Published: March 2003

The aim of this study was to isolate and characterize the paramylon synthesizing enzyme from Euglena gracilis Klebs. A method for enzyme solubilization with high synthase activity using the zwitterionic detergent 3‐[(3‐cholamidopropyl)‐dimethylammonio]‐1‐propane sulfonate is presented. Fractionated purification showed that the main enzyme activity was associated with the paramylon granula fraction, isolated from heterotrophically grown cells of E. gracilis. Further purification by sucrose density centrifugation resulted in a large enzyme complex with an apparent molar mass of 670 kDa (native). The complex remained active throughout the isolation procedures and produced beta‐1,3‐glucan in vitro. Two polypeptides of 37 and 54 kDa could be identified by photoaffinity labeling with [32P]‐UDP‐glucose as substrate after SDS‐PAGE.
CIRCADIAN GROWTH IN PORPHYRA UMBILICALIS (RHODOPHYTA): SPECTRAL SENSITIVITY OF THE CIRCADIAN SYSTEM
Authors: Lüning Klaus
Published: March 2003

The circadian rhythm in growth of the red macroalga Porphyra umbilicalis (Linnaeus) J. Agardh was investigated under different spectral light conditions in laboratory‐grown thalli. A free‐running rhythm was observed in constant green or red light at irradiances of 2.5 to 20 μmol photons·m−2·s−1, whereas arhythmicity occurred in constant blue light at 6–20 μmol photons·m−2·s−1. The circadian oscillator controlling growth rhythmicity in Porphyra uses most of the visible sunlight spectrum and possibly multiple photoreceptors with a high sensitivity for blue light and a lower sensitivity for red light. This was inferred from three experimental results: (1) The free‐running period, τ, of the growth rhythm decreased with increasing irradiance, from approximately 25 h at 2.5 μmol photons·m−2·s−1 to 22 h at 20 μmol photons·m−2·s−1 in red or green light, (2) Dark pulses of 3 h duration, interrupting otherwise continuous green or red light, caused advances during the subjective day and delays during the subjective night; the circadian oscillator in Porphyra can discriminate darkness from green or red light, and (3) Low‐irradiance blue light pulses (2.5 μmol photons·m−2·s−1) shifted the growth rhythm in red light of higher irradiance (e.g. 10 μmol photons·m−2·s−1), and a strong, high amplitude, type 0 phase response curve was obtained that is usually observed with light pulses shifting a circadian rhythm in otherwise continuous darkness.
cAMP IN THE CELL CYCLE OF THE DINOFLAGELLATE CRYPTHECODINIUM COHNII (DINOPHYTA)
Authors: Lam Connie M. C. , New D. C. , Wong Joseph T. Y.
Published: March 2003

The second messenger cAMP is a key regulator of growth in many cells. Previous studies showed that cAMP could reverse the growth inhibition of indoleamines in the dinoflagellate Crypthecodinium cohnii Biecheler. In the present study, we measured the level of intracellular cAMP during the cell cycle of C. cohnii. cAMP peaked during the G1 phase and decreased to a minimum during S phase. Similarly, cAMP‐dependent protein kinase activities peaked at both G1 and G2+M phases of the cell cycle, decreasing to a minimum at S phase. Addition of N6, O2′‐dibutyryl (Bt2)‐cAMP directly stimulated the growth of C. cohnii. Flow cytometric analysis of synchronized C. cohnii cells suggested that 1 mM cAMP shortened the cell cycle, probably at the exit from mitosis. The size of Bt2‐cAMP treated cells at G1 was also larger than the control cells. The present study demonstrated a regulatory role of cAMP in the cell cycle progression in dinoflagellates.
ZYGOSPORE GERMINATION IN CHLAMYDOMONAS MONOICA (CHLOROPHYTA): TIMING AND PATTERN OF SECONDARY ZYGOSPORE WALL DEGRADATION IN RELATION TO CYTOPLASMIC EVENTS
Authors: Malmberg Amy E. , VanWinkle‐Swift Karen P.
Published: March 2003

The Chlamydomonas monoica Strehlow zygospore is a dormant heavily walled spore adapted to survive extreme environmental conditions. The zygospore wall is multilayered and includes an acetolysis‐resistant component related to the general class of compounds referred to as sporopollenin. Germination of the zygospore requires induction and completion of nuclear meiotic divisions, cytokineses to produce the four vegetative progeny cells, and breakdown of the zygospore wall to allow progeny release. Analysis of zygospore wall breakdown by transmission electron microscopy of synchronously germinating zygospores revealed differences in the timing and nature of disintegration of the various wall layers. Breakdown of the outer trilamellar sheath occurred within 6 h after light induction, concomitant with the onset of prophase I. At the same time, stored lipid bodies were consumed and replaced by large cytoplasmic vacuoles. Degradation of the inner more massive wall layer was initiated several hours later at about the time of the second meiotic division. In areas beneath breaks in the trilamellar sheath, a fibrous electron opaque bridge of wall material was retained whereas degradation of the remainder of the inner layer progressed. Finally, disintegration of this bridge material, after the completion of the meiotic divisions and synthesis of progeny cell walls, resulted in the opening of large slits in the trilamellar sheath, allowing escape of the flagellated vegetative progeny. The chloroform resistance typical of mature zygospores was lost at approximately the same time that the initial breaks in the trilamellar sheath were detected but before disintegration of the inner wall layer(s).
ULTRASTRUCTURE OF PHACUS TRYPANON (EUGLENOPHYCEAE) WITH AN EMPHASIS ON STRIATED FIBER AND MICROTUBULE ARRANGEMENT
Authors: Shin Woongghi , Boo Sung Min
Published: March 2003

Phacus trypanon Pochmann is a photosynthetic euglenoid that is known to have typical characteristics of the Euglenales. The ultrastructure of P. trypanon was examined with particular attention being given to the striated fibers of both the basal body complex and feeding apparatus and microtubule arrangement. As in other euglenoids, the basal body complex was associated with the striated and fibrous fibers. The singlet microtubules at the reservoir level were arranged into doublets by a successive linkage of the existing adjacent microtubules at the transition level, and doublets were rearranged into a three‐over‐two pattern of cytoskeletal microtubules that were continuous with the subpellicular microtubules. The most striking feature of the feeding apparatus of P. trypanon was the prominent striated fiber that originated from the reservoir membrane and became arc shaped with electron‐opaque bands at the lower canal level. The reinforcing microtubular band (MTR)/pocket of P. trypanon was associated with a prominent striated fiber that may act as a nucleating site for the semicircular microtubules, which surround the canal. The striated fiber and MTR/pocket are usually only found in those taxa that have a well‐developed feeding apparatus and lack plastids; therefore, we speculate that the ingestion apparatus is functional in P. trypanon, which likely diverged in the early history of the photosynthetic green euglenoids.
SEASONALITY AND THERMAL ACCLIMATION OF REACTIVE OXYGEN METABOLISM IN FUCUS VESICULOSUS (PHAEOPHYCEAE)
Authors: Collén Jonas , Davison Ian R.
Published: March 2003

The intertidal brown macroalga Fucus vesiculosus L. acclimates its defense against reactive oxygen in response to both (1) growth at different temperatures in laboratory culture and (2) seasonal changes in environmental conditions. Fucus vesiculosus was grown in seawater at 0° C, 20° C, and at 0° C with a 3‐h daily emersion at −10° C. Algae grown at low temperature, both with and without freezing, produced less reactive oxygen after severe freezing stress than those grown at 20° C. These differences were correlated with growth temperature‐induced changes in activities of superoxide dismutase (SOD), glutathione reductase, and ascorbate peroxidase. The contents of tocopherols increased with increased cultivation temperature, whereas the activity of catalase and the content of glutathione and ascorbate did not change. Growth at 0° C increased the resistance of photosynthesis to freezing and reduced photoinhibition in high light at 5° C; the latter effect was further increased in algae subject to daily freezing. These data suggest that elevated activity of reactive oxygen scavenging enzymes, especially SOD, increases the resistance to photoinhibition, at least at low temperature, as well as being important for freezing tolerance. Seasonal changes in reactive oxygen metabolism showed a similar pattern to those elicited by temperature in laboratory culture. Summer samples had lower activities of most reactive oxygen scavenging enzymes than algae collected in autumn and winter when water temperatures were lower. In contrast to the laboratory experiments, ascorbate content did change and was lower during the winter than summer, whereas the content of glutathione was not influenced by season. Overall, the data not only indicate that temperature plays an important role in the regulation of stress tolerance and reactive oxygen metabolism but also suggest that other factors are also involved.
LONG‐TERM CHANGES IN THE MACROALGAL VEGETATION OF THE INNER GULLMAR FJORD, SWEDISH SKAGERRAK COAST1
Authors: Eriksson Britas Klemens , Johansson Gustav , Snoeijs Pauli
Published: March 2003

We examined long‐term changes in the macroalgal vegetation at Stora Bornö Island in the inner Gullmar Fjord on the Swedish Skagerrak coast. This was made possible by access to a 1941 diving investigation. The same sites were reinvestigated in 1998. Community composition and depth distributions of species were compared and changes were analyzed with focus on functional groups (size, thallus shape, and life‐history traits). We discovered a significant decrease in the depth extension of macroalgal species and a dramatic decline of species richness in the lower littoral (below 16 m of depth) compared with 57 years earlier. Ordination analysis revealed that there was a significant difference in the community composition between the two study periods. In general, small (<10 cm), thin, filamentous, and aseasonal ephemerals increased in relative abundance, whereas larger (>10 cm), coarsely branched, and perennial algae decreased. Calibrations of individual species to local sediment cover, using canonical correspondence analysis, indicated that part of the change in species composition was related to sediment load. Furthermore, large‐scale climate differences (NAO Winter Index) between the study periods indicated a higher impact of Baltic Sea and Kattegat water in the nutrient dynamics of the fjord in the 1998 study. We concluded that the observed long‐term changes in the macroalgal community at Stora Bornö Island were consistent with an increased nutrient availability.
HETEROSIGMA AKASHIWO (RAPHIDOPHYCEAE) RESTING CELL FORMATION IN BATCH CULTURE: STRAIN IDENTITY VERSUS PHYSIOLOGICAL RESPONSE 1,2
Authors: Han Myung‐Soo , Kim Young‐Pil , Cattolico Rose Ann
Published: March 2003

In this study, we examined the impact of environmental perturbation on the movement of the toxic bloom‐forming alga Heterosigma akashiwo (Hada) Hada ex Y. Hara et Chihara [syn. H. carterae (Hulburt) F.J.R. Taylor] between vegetative and resting cell phases of the life history. Resting state induction, in batch culture, was most effective when vegetative cells were subjected to low temperature (10° C) and darkness for extended time periods. Heterosigma cells in stasis had neither a cell wall nor scales but were surrounded by a calyx, most probably of polysaccharide composition. The resting cell was completely immobile, although both flagella remained attached. Heterosigma resting cells did not require a maturation period before successful activation to the vegetative state could occur. Cell division and motility were impacted sequentially during both the induction and activation phases of resting cell development. Our data show that Heterosigma had an obligate light requirement for resting cell activation. In replete medium, very low light fluences of 5 μmol photons·m−2·s−1 were as effective as 60 μmol photons·m−2·s−1 in the initiation of activation. Such sensitivity to extremely low light might give Heterosigma a competitive advantage for bloom formation in nature. Reduced nitrate levels significantly shortened the temporal transition of vegetative cells into the resting cell phase of the life history. Additionally, when resting cells induced in nitrate‐limited medium were activated under nitrate‐replete condition, the efficiency of the activation response was directly correlated to light availability. Both vegetative and resting cells maintained a haploid DNA complement. Rapid amplified polymorphic DNA (RAPD) analysis demonstrated variation in genetic identity among axenic Heterosigma strains. Strain identity influenced success in resting cell induction and survival in stasis. To date, no defined sexual cycle has been described. These observations are discussed in terms of population fitness. The data presented in this report provide a model algal system wherein the molecular events that govern long‐term stasis in an obligately autotrophic organism can now be assessed.
DIEL PATTERNS IN LIGHT ABSORPTION AND ABSORPTION EFFICIENCY FACTORS OFISOCHRYSIS GALBANA(PRYMNESIOPHYCEAE)1
Authors: Ohi Nobuaki , Ishiwata Yuki , Taguchi Satoru
Published: March 2003

The chlaspecific absorption coefficients [a* (λ), m2·mg chla−1] were examined in chemostat culture of the PrymnesiophyceaeIsochrysis galbana(Parke) under a 12:12‐h light:dark cycle at low light (75 μmol photons·m−2·s−1) and high light (500 μmol photons· m−2·s−1) conditions. Other associated measurements such as pigment composition, cell density, and diameter as the measure of cell size were also made at the two light regimes every 2 h for 2 days to confirm the periodicity. A distinct diel variability was observed for thea* (λ) with maxima near dawn and minima near dusk. The magnitude of diel variation ina* (440) was 15% at low light and 22% at high light. Pronounced diel patterns were observed for cell size with minima near dawn and maxima near dusk. The magnitude of diel variation in cell size was 9.3% at low light and 21% at high light. The absorption efficiency factors [Q  a(440)] were determined by reconstruction using intracellular concentrations of pigments and cell size. TheQ  a(440) also showed a distinct diel variability, with minima near dawn and maxima near dusk. The diel variation ina* (λ) andQ  a(λ) was primarily caused by changes in cell size due to growth, although there was some influence from diel variations in the intracellular pigment concentrations. The results presented here indicated that diel variation ina* (λ) was an important component of the optical characterization of phytoplankton.
ACCLIMATION OF PHOTOSYNTHESIS AND PIGMENTS DURING AND AFTER SIX MONTHS OF DARKNESS IN PALMARIA DECIPIENS (RHODOPHYTA): A STUDY TO SIMULATE ANTARCTIC WINTER SEA ICE COVER1
Authors: Lüder Ulrike H. , Wiencke Christian , Knoetzel Jürgen
Published: March 2003

The influence of seasonally fluctuating photoperiods on the photosynthetic apparatus of Palmaria decipiens (Reinsch) Ricker was studied in a year‐round culture experiment. The optimal quantum yield (Fv/Fm) and the maximal relative electron transport rate (ETRmax), measured by in vivo chl fluorescence and pigment content, were determined monthly. During darkness, an initial increase in pigment content was observed. After 3 months in darkness, ETRmax and Fv/Fm started to decrease considerably. After 4 months in darkness, degradation of the light‐harvesting antennae, the phycobilisomes, began, and 1 month later the light harvesting complex I and/or the reaction centers of PSII and/or PSI degraded. Pigment content and photosynthetic performance were at their minimum at the end of the 6‐month dark period. Within 24 h after re‐illumination, P. decipiens started to accumulate chl a and to photosynthesize. The phycobiliprotein accumulation began after a time lag of about 7 days. Palmaria decipiens reached ETRmax values comparable with the values before darkness 7 days after re‐illumination and maximal values after 30 days of re‐illumination. Over the summer, P. decipiens reduced its photosynthetic performance and pigment content, probably to avoid photodamage caused by excess light energy. The data show that P. decipiens is able to adapt to the short period of favorable light conditions and to the darkness experienced in the field.
Are ‘Green TIDES’ Harmful Algal Blooms? Allelopathic Properties of Extracts from Ulva Fenestrata and Ulvaria Obscura
Authors: Nelson T. A. , Lee D. , Smith B. C. , Prins R.
Published: March 2003

Toxic properties are rarely associated with macroalgal blooms. A few studies have demonstrated inhibition of invertebrate larval development by extracts from Ulva spp. and we have observed substantial discoloration of the seawater in small bays following mass desiccation‐induced mortality of Ulvaria obscura. We examined the effects of extracts from Ulva fenestrata and U. obscura on enzyme systems, larval oyster development, Fucus gardneri zygote development, epiphytic diatom growth, and growth of Ulva and Ulvaria. Extracts from Ulvaria inhibited trypsin activity, but not pepsin or amyloglucosidase activity when tested at pH optimized for each enzyme system (pH 8, 2, and 5.5, respectively). When tested at neutral to slightly alkaline pH (7 or 8), Ulvaria extracts also inhibited amyloglucosidase activity. ‘Aged’ extract caused greater enzyme inhibition than fresh extract. Maximum inhibition occurred in 6‐h‐old‐extract. Oyster larval development was inhibited by extracts from both algae, although the visible effects were much greater when the larvae were exposed to extracts of Ulvaria. Fucus zygote development was inhibited by extracts of both species, although the effect was measurably greater in extracts from Ulvaria. Epiphytic diatom growth and growth of Ulva and Ulvaria were inhibited by extracts from both species. Thus, extracts from both Ulva fenestrata and U. obscura have allelopathic properties, although the impacts are more widespread for Ulvaria extracts. These properties could alter competitive interactions by inhibiting germination or development of algal and animal competitors. Multiple toxins are probably involved, since the two species tested cause visibly different responses.
Are Older Hazardous and Harmful Drinkers Less Likely To Participate in Health‐Related Behaviors and Practices as Compared with Nonhazardous Drinkers?
Authors: Moore Alison A. , Morgenstern Hal , Harawa Nina T. , Fielding Jonathan E. , Higa Jerilyn , Beck John C.
Published: March 2003

OBJECTIVES: To describe the (1) prevalence of at‐risk drinking and participation in health‐related behaviors and practices and (2) associations of at‐risk drinking with other health‐related behaviors and practices among older persons completing a health‐risk appraisal for the elderly (HRA‐E).

DESIGN: Cross‐sectional study using data from a self‐administered, mailed survey sample.

SETTINGS: Persons from three organizations were surveyed: (1) the American Association of Retired Persons; and (2) a large medical group and (3) a community‐based senior health center in southern California.

PARTICIPANTS: 1,889 persons age 55 years and older.

MEASUREMENTS: The HRA‐E included items on health characteristics, drinking behaviors (including amount of alcohol use and two alcoholism screening measures: the CAGE (Cut down, Annoyed, Guilty, Eye opener) and Short Michigan Alcoholism Screening Test‐Geriatric version (SMAST‐G), and participation in selected health‐related behaviors and practices. Social drinkers were defined as those who drank fewer than 14 drinks weekly and screened negative on the CAGE (defined as two or more “no” responses) and SMAST‐G. Hazardous drinkers drank fewer than 14 drinks weekly and screened negative. Harmful drinkers drank fewer than 14 drinks weekly and screened positive. Possible at‐risk drinkers drank 14 or more drinks weekly and screened positive. Least squares regression models were used to assess the effects of hazardous, harmful, and possible at‐risk drinking on each of the health‐related practices and behaviors. We also conducted these analyses using three other definitions of social, possible at‐risk, hazardous, and harmful drinking.

RESULTS: Of all respondents, 40% were social drinkers, 3% were harmful drinkers, 2% were hazardous drinkers, and 11% were possible at‐risk drinkers. Hazardous, harmful, and possible at‐risk drinkers commonly reported driving after drinking or being driven by someone who had been drinking (67%, 76%, and 64% respectively). Harmful and possible at‐risk drinkers were more likely than social drinkers to smoke and were less likely to use seatbelts regularly. These findings were observed regardless of how the drinking groups were defined.

CONCLUSION: All groups of at‐risk drinkers more commonly engaged in selected adverse health‐related behaviors and practices than did social drinkers.
A Controlled Study of MRI Signal Hyperintensities in Older Depressed Patients with and without Hypertension
Authors: Greenwald Blaine S. , Kramer‐Ginsberg Elisse , Krishnan K. Ranga Rama , Hu Jian , Ashtari Manzar , Wu Houwei , Aupperle Peter , Patel Mahendra , Pollack Simcha
Published: March 2003

OBJECTIVES:

To compare the frequency/severity of signal hyperintensities—likely markers of cerebrovascular disease—in the subcortical gray and deep white matter on magnetic resonance imaging (MRI) scans of brains of hypertensive and normotensive older depressed and nondepressed comparison subjects.

DESIGN:

Between‐groups comparison of cross‐sectional MRI data employing analyses of covariance controlling for the effects of age, gender, and height.

SETTING:

A comprehensive inpatient‐outpatient geriatric psychiatry service in a university hospital.

PARTICIPANTS:

Nondemented older depressed (n = 81) and nondepressed comparison (n = 70) subjects divided into four groups (hypertensive depressed (n = 40), hypertensive normals (n = 21), normotensive depressed (n = 41), normotensive normals (n = 49)).

MEASUREMENTS:

Signal hyperintensities were rated on T‐2 weighted MRI scans blind to patient diagnoses employing two standardized hyperintensity rating systems (Fazekas, Boyko).

RESULTS:

Hypertensive depressives had significantly more‐severe hyperintensity ratings in both subcortical gray and deep white matter than did normotensive depressives and controls (P < .05) and significantly more‐severe hyperintensity ratings only in subcortical gray matter (P < .05) than did hypertensive controls. Hypertensive controls had significantly more‐severe ratings in deep white matter than either normotensive group (P < .05).

CONCLUSIONS:

Findings suggest a relationship between deep white matter hyperintensities and hypertension (regardless of depressive state), and a particular role of subcortical gray matter hyperintensities (possibly interacting with more‐severe deep white matter lesions) in older depressed hypertensives, as compared with older depressed normotensives of similar ages and severity of depression. These data support possible heterogeneous pathogenic contributions in late‐life depression subgroups, one of which appears to be influenced by cerebrovascular disease. J Am Geriatr Soc 49:1218–1225, 2001.
Frequency of Alzheimer's Disease and Other Dementias in a Community Outreach Sample of Hispanics
Authors: Fitten L. Jaime , Ortiz Freddy , Pontón Marcel
Published: March 2003

OBJECTIVES:

To determine the proportion of Alzheimer's disease (AD) and other dementia types in a community sample of Hispanics.

DESIGN:

This is a descriptive diagnostic study of a nonrandom community outreach sample utilizing established criteria for the diagnosis of dementia type. Recruitment involved direct community outreach with diagnostic evaluations conducted at a university‐affiliated outpatient clinic.

SETTING:

Hispanic Neuropsychiatric and Memory Research Clinic at the Olive View‐UCLA Medical Center in Sylmar, California.

PARTICIPANTS:

One hundred community‐dwelling Hispanics age 55 and older without prior diagnosis or treatment of their cognitive symptoms.

MEASUREMENTS:

Each subject underwent a complete medical diagnostic evaluation, in Spanish, including neuropsychological tests, neurological examination, laboratory tests, and brain imaging (computed tomography or magnetic resonance imaging) to establish dementia type. Presence of dementia was established according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM‐IV) criteria. Diagnosis for probable or possible AD and vascular dementia (VascD) was established using criteria from the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association for probable AD and by research criteria from the National Institute of Neurological Disorders and Stroke and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences for VascD, respectively. Frontotemporal dementia was diagnosed using recommendations set forth by the Lund and Manchester groups.

RESULTS:

Subjects were poor, with low acculturation levels despite long years of U.S. residence. Forty percent of subjects had had undiagnosed cognitive symptoms for 3 or more years. Of those demented,65 38.5% had AD and 38.5% met criteria for VascD. The best predictors of VascD were hypertension and cerebrovascular disease, whereas apolipoprotein E4 allele best predicted AD. Other forms of dementia were also present. Twenty percent of the sample was clinically depressed but not demented.

CONCLUSIONS:

In comparison with data from predominantly white populations, our proportion of AD cases was lower and that of VascD cases was considerably higher than anticipated. The percentage of clinically depressed older individuals was also high. These findings could have implications for differential cultural and genetic risk factors for dementia among diverse ethnic/racial groups. Further studies are needed to obtain accurate prevalence estimates of dementing disorders among the different U.S. Hispanic populations. J Am Geriatr Soc 49:1301–1308, 2001.
Depressive Disorder as a Predictor of Physical Disability in Old Age
Authors: Kivelá Sirkka‐Liisa , Pahkala Kimmo
Published: March 2003

OBJECTIVES: To determine whether the occurrence of depression predicts physical disability in older people.

DESIGN: A longitudinal epidemiological study with a follow‐up of 5 years.

SETTING: A comparison between depressed and nondepressed participants.

PARTICIPANTS: The series consisted of the persons who participated in the longitudinal epidemiological study on depression in old age performed in Ähtäri, Finland. The first round of interviews and examinations was performed in 1984/1985 and the second round in 1989/1990. The study series (N = 786) was composed of persons functionally independent in activities of daily living (ADLs) during the first round and alive and participating in both rounds.

MEASUREMENTS: Depression was determined according to DSM‐III criteria. Physical functional abilities were measured with self‐assessments of ability to manage ADLs.

RESULTS: In bivariate analyses, depression at the baseline did not predict lowering of functional abilities during follow‐up, but the occurrence of depression with a long term or relapsing course during follow‐up and the onset of depression during follow‐up in persons not depressed at the baseline predicted lowering of functional abilities during follow‐up. The logistic regression analyses showed the presence of the following variables measured during the first round—older age, low basic education, poor self‐perceived health, and occurrence of a physical disease—and the onset of the following diseases during follow‐up—any physical disease, neurological disease, cerebrovascular disease, or depressive symptoms (in persons nondepressed at the baseline)—predicted lowered functional abilities after a follow‐up of 5 years.

CONCLUSION: Depression that developed during the follow‐up in previously nondepressed persons was associated with an increased risk for lowering of functional abilities, even when controlling for age, sociodemographic factors, physical diseases, and baseline disabilities. Depressed older people are at high risk for physical disability, and an individually planned program to maintain their functional abilities by training in ADLs and instrumental activities of daily living (IADLs) and physical exercise should be included in their treatment.
Gaps in Asthma Care of the Oldest Adults
Authors: Wolfenden Linda L. , Diette Gregory B. , Skinner Elizabeth Ann , Steinwachs Donald M. , Wu Albert W.
Published: March 2003

OBJECTIVES: To assess the adequacy of asthma care reported by a group of older adults who were subsequently hospitalized for their asthma.

DESIGN: Prospective cohort study.

SETTING: Fifteen managed care organizations in the United States.

PARTICIPANTS: Adults with asthma, enrolled in managed care.

MEASUREMENTS: Patient survey of demographics, asthma symptoms, health status, comorbid conditions, asthma treatment, asthma knowledge, and asthma self‐management at baseline and 1 year later.

RESULTS: Of 254 older adults, 38 (15.0%) reported being hospitalized for asthma at 1‐year follow‐up. Of these, 22.9% owned a peak flow meter (PFM). Of those with allergies, only about half (56.0%) had been told how to avoid allergens and had been referred for formal allergy testing. Adrenergic drug use was high in some patients. Nearly all (94.6%) used β‐agonist metered‐dose inhalers (MDIs); 60.0% reported theophylline; 17.1% reported β‐agonist MDI overuse (>8 puffs per day); 10.5% reported β‐agonist MDI over‐use and theophylline; and 13.2% reported both β‐agonist MDI over‐use and oral β‐agonist use. Only 18.4% of respondents rated their overall asthma attack knowledge as excellent. Compared with nonhospitalized older adults, the hospitalized group reported care that was more consistent with guidelines, but also higher rates of potentially toxic combinations of adrenergic drugs. Compared with younger hospitalized adults, older hospitalized adults had clear deficiencies, including lower use of PFMs (55.3% vs 22.9%) and worse asthma self‐management knowledge.

CONCLUSIONS: There are many opportunities to improve both the pharmacologic and non‐pharmacologic care of older adults with asthma. Overuse of and potentially toxic combinations of inhaled and oral sympathomimetics should probably be avoided. Older asthmatics may also benefit from increased specialty referral, PFM use, allergy testing, and asthma teaching.
Prevalence of Impaired Swallowing in Institutionalized Older People in Taiwan
Authors: Lin Li‐Chan , Wu Shiao‐Chi , Chen Hwa Shen , Wang Tyng‐Guy , Chen Miao‐Yen
Published: March 2003

OBJECTIVES: To investigate the prevalence of impaired swallowing in residents at long‐term care facilities (LTCFs) in Taiwan.

DESIGN: A chart review, a structured questionnaire completed at interview, a neurological examination, and a timed swallowing test were used to assess impairment and to gather demographic data.

SETTING: Nine skilled nursing facilities and nine intermediate‐care facilities in metropolitan Taipei.

PARTICIPANTS: One thousand two hundred twenty‐one conscious and unconscious residents with a mean age of 77.07.

MEASUREMENTS: Impaired swallowing was defined when a subject met two or more of the following criteria: self‐report of swallowing difficulty, a score of 2 or more derived from a swallowing questionnaire combined with a neurological examination investigating symptoms and signs of impairment, and coughing/choking during a timed swallowing test or a measured swallowing rate (volume swallowed per second) below the 10th percentile as derived from a gender‐based study of an older community in Taipei.

RESULTS: Of the 1,221 subjects, 356 (29.2%) were fed by tube. The prevalence rates for impaired swallowing as estimated were 97.5% and 31.9% for tube‐fed and non‐tube‐fed subjects respectively, whereas the overall prevalence for tube‐fed and non‐tube‐fed subjects altogether was 51.0%.

CONCLUSIONS: The findings may serve to increase awareness of this problem among healthcare professionals in LTCFs. Further research is contemplated to investigate whether early identification makes a difference in treatment choices and outcomes.
Similarities and Differences in Attitudes Toward Long‐Term Care Between Japanese Americans and Caucasian Americans
Authors: McCormick Wayne C. , Ohata Cynthia Y. , Uomoto Jay , Young Heather M. , Graves Amy B. , Kukull Walter , Teri Linda , Vitaliano Peter , Mortimer James A. , McCurry Susan M. , Bowen James D. , Larson Eric B.
Published: March 2003

The purpose of this study was to compare attitudes toward the use of long‐term care between older Japanese Americans (n = 1,244) and older Caucasian Americans (n = 1,354). When presented with a hypothetical situation in which they have dementia, 39% of older Japanese Americans and 42% of older Caucasians intended to be cared for at home, whereas 53% versus 38%, respectively, intended to use nursing home care (P < .001). If the hypothetical situation was hip fracture, 81% of older Japanese Americans and 72% of older Caucasians intended to be cared for at home, with 13% of both groups intending to use nursing home care (P = NS). The subjects' perceptions of what their families, friends, ministers, and communities would want them to choose differed, with more uncertainty among Caucasians (P < .001). For provision of home care, Japanese Americans were more likely to rely on loved ones than Caucasians, who were more likely to rely on paid providers. Multivariate logistic regression showed ethnicity to be independently related to intention to use nursing home care in the dementia scenario, controlling for demographic variables. Being married lowered the odds of intending to use nursing homes in any situation. We conclude that Caucasian Americans intend to use paid home health care at higher rates than Japanese Americans if they become disabled by dementia. Japanese Americans demonstrated more certainty about the influences of others on their opinions, suggesting a more stable cultural norm in this population, and intended to use more nursing home care in the event of permanent debility (dementia).
Clinical Features of Influenza A Virus Infection in Older Hospitalized Persons
Authors: Walsh Edward E. , Cox Christopher , Falsey Ann R.
Published: March 2003

OBJECTIVES: To determine the value of clinical parameters in predicting influenza in older persons and those with underlying cardiopulmonary conditions hospitalized with respiratory illnesses.

DESIGN: Prospective evaluation of hospitalized persons from November 15, 1999, to April 15, 2000.

SETTING: A 450‐bed general medical‐surgical hospital in Rochester, New York.

PARTICIPANTS: Patients aged 65 and older or those with underlying cardiopulmonary conditions admitted to the hospital with respiratory diagnoses.

MEASUREMENTS: The ability to discriminate influenza from noninfluenza cases using clinical parameters. Influenza infection was documented by culture, rapid antigen detection, reverse transcription‐polymerase chain reaction, or serology.

RESULTS: Sixty‐one influenza A infections (mean age ± standard deviation = 79 ± 10) were identified in 332 evaluated illnesses (18.3%). Fifty‐six cases occurred in 168 patients (33%) during a 9‐week epidemic period; 40 were considered contagious on the basis of a positive culture or antigen test. Neither single clinical parameters nor logistic regression analysis using all parameters clearly discriminated influenza from noninfluenza cases. The complex of cough, temperature of 38°C or higher, and illness duration of 7 days or less provided the best discrimination between infected and uninfected subjects; during the epidemic period, 53% of subjects with this symptom complex had influenza, compared with 18% without these symptoms (relative risk = 2.99, 95% confidence interval = 1.85–4.83). This symptom complex had a sensitivity of 78% and a specificity of 73% for contagious influenza during the epidemic period.

CONCLUSIONS: In older persons and those with underlying cardiopulmonary conditions admitted with acute respiratory illness during influenza epidemics, the presence of fever, cough, and brief illness should be useful for institution of respiratory isolation and for design of antiviral trials.
Standardization of Plasma Brain Natriuretic Peptide Concentrations in Older Japanese—Relationship to Latent Renal Dysfunction and Ischemic Heart Disease
Authors: Nomura Hideki , Hayashi Toshio , Esaki Teiji , Kanda Shigeru , Kano Hatsuyo , Hattori Ayako , Iguchi Akihisa
Published: March 2003

OBJECTIVES: To determine the contributors to elevating plasma brain natriuretic peptide (BNP) concentrations in older people with normal systolic function. To investigate the relationship between cyclic guanosine monophosphate (cGMP) and BNP in older people with and without ischemic heart disease (IHD).

DESIGN: Observational study.

SETTING: Hospitalized patients in Nagoya University Hospital from November 1997 to May 2000.

PARTICIPANTS: Younger patients (<65) without IHD (n = 31), older patients (≥65) without IHD (n = 37), and older patients with stable IHD (n = 32). All participants showed 45% or greater of their left ventricular ejection fraction (LVEF).

MEASUREMENTS: LVEF, peak atrial velocity/peak early velocity (A/E) ratio at the mitral valve, and left ventricular mass volume were measured using transthoracic echocardiogram. Plasma BNP level, cGMP, and serum creatinine (Scr) were measured. Creatinine clearance (CLcr) was calculated based on 24‐hour urine collection.

RESULTS: Plasma BNP levels in older people with and without IHD were significantly greater than in younger patients (mean ± standard deviation = 76.4 ± 96.0 (P < .001), 165.2 ± 200.6 (P < .001), and 8.1 ± 7.0, respectively). By simple regression analysis, in the groups without IHD, the logarithm of plasma BNP (Log BNP) concentrations had a significant positive relationship with age (R = 0.657, P < .001), Scr (R = 0.449, P < .001), and A/E ratio (R = 0.326, P = .003) and a significant negative relationship with CLcr (R = −0.663, P < .001). A stepwise multiple regression analysis with Log BNP level as the dependent variable and age, Scr, CLcr, and A/E ratio as independent variables showed that CLcr was a significant independent contributor in groups without IHD (R = −0.766, P < .001). In this analysis, the regression coefficient of the intercept was 2.006, and that of CLcr was −0.010. The cGMP/BNP ratio in older subjects with stable IHD tended to be lower than in those without IHD (P = .063).

CONCLUSIONS: Elevated BNP levels in older patients with normal systolic function may be in part due to latent renal dysfunction, despite normal Scr levels. In healthy older people, it is important to exclude the effects of latent renal function in assessing cardiac function according to BNP level. In older subjects with stable IHD, the cGMP/BNP ratio tended to be lower than in those without IHD. This may be a reflection of a poor response of cGMP to BNP.
Chlamydia Trachomatis in Older Los Angeles County Residents, 1991–1998: Implications and Recommendations for the Detection of Sexually Transmitted Infections in Older Age Groups
Authors: Smith Lisa V. , Malmgren Roberta , Dyer Irene E. , Sorvillo Frank , Vaughn Gregory S. , Visscher Barbara
Published: March 2003

OBJECTIVES: This study examined the incidence and implications of reported chlamydia cases in Los Angeles County residents aged 50 and older.

DESIGN: Observational study of passive surveillance data submitted to the Los Angeles County Sexually Transmitted Disease Program.

SETTINGS: Private and public health facilities in Los Angeles County.

PARTICIPANTS: Los Angeles County residents aged 50 and older.

MEASUREMENTS: Chlamydia cases were identified from the Los Angeles County Sexually Transmitted Disease Program passive surveillance system reports received from 1991 to 1998.

RESULTS: Between 1991 and 1998, 1,421 cases of chlamydia were reported in persons aged 50 and older in Los Angeles County, accounting for 1% of total chlamydia cases. The average annual incidence rate for this period was 9.3 per 100,000, and appeared relatively stable. The mean age ± standard deviation was 59.0 ± 9.2 years, with a range of 50 to 96 years. Rates for older women were 1.1 to 3.0 times higher than in older men, similar to rate ratios for 20‐ to 35‐year‐olds. Rates among older African Americans appear to be substantially higher than any other older racial/ethnic group.

CONCLUSIONS: Our data show that there are no age barriers for sexually transmitted infections. Although this population is highly unlikely to experience adverse reproductive outcomes, transmission to younger sex partners and contribution to the overall chlamydia epidemic are serious concerns. Surveillance and prevention strategies aimed at older persons will be needed as this population continues to grow.
Response of Elevated Methylmalonic Acid to Three Dose Levels of Oral Cobalamin in Older Adults
Authors: Rajan Suparna , Wallace Jeffrey I. , Brodkin Kayla I. , Beresford Shirley A. , Allen Robert H. , Stabler Sally P.
Published: March 2003

OBJECTIVES: Because the effects of lower‐dose oral cobalamin (Cbl) supplements on older people with cobalamin deficiency are not known, we determined whether oral Cbl supplements at three different dose levels would normalize elevated serum methylmalonic acid (MMA) and total homocysteine (tHcy) concentrations.

DESIGN: Sequential nonrandomized intervention study of three dose levels.

SETTINGS: Two university‐based senior care clinics.

PARTICIPANTS: Twenty‐three older adults (aged ≥65) with serum Cbl levels of 221 pmol/L (300 pg/mL) or lower and serum MMA greater than 271 nmol/L who had been enrolled in a previous screening study for Cbl deficiency (mean age 79 ± 9; 17 male, 6 female; 17 white, 6 other).

INTERVENTION: Sequential daily treatment with 25 μg oral cobalamin, followed by 100 μg and 1,000 μg cobalamin each for a 6‐week period.

MEASUREMENTS: Serum MMA, tHcy, and other metabolites at baseline and after each 6‐week dosing interval.

RESULTS: Treatment with 25 μg and 100 μg lowered but did not normalize MMA levels in most subjects. A dose of 1,000 μg/day proved to be the most effective in lowering MMA levels to within normal limits. Serum tHcy was normalized in six of 11 subjects who had elevated tHcy pretreatment with oral Cbl alone and in one subject in combination with a multivitamin.

CONCLUSIONS: Most Cbl‐deficient older people require more than 100 μg of oral Cbl to normalize serum MMA, which is a larger dose than is available in most standard multivitamins and Cbl supplements.