bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuropsychological consequences of regular marijuana use: a twin study
Authors: LYONS M. J. , BAR J. L. , PANIZZON M. S. , TOOMEY R. , EISEN S. , XIAN H. , TSUANG M. T. 
Published: October 2004

Background. Results of previous research examining long-term residual effects of marijuana use on cognition are conflicting. A major methodological limitation of prior studies is the inability to determine whether differences between users and non-users are due to differences in genetic vulnerability preceding drug use or due to the effects of the drug.Method. Fifty-four monozygotic male twin pairs, discordant for regular marijuana use in which neither twin used any other illicit drug regularly, were recruited from the Vietnam Era Twin Registry. A minimum of 1 year had passed since the marijuana-using twins had last used the drug, and a mean of almost 20 years had passed since the last time marijuana had been used regularly. Twins were administered a comprehensive neuropsychological test battery to assess general intelligence, executive functioning, attention, memory and motor skills. Differences in performance between marijuana-using twins and their non-using co-twins were compared using a multivariate analysis of specific cognitive domains and univariate analyses of individual test scores. Dose–response relationships were explored within the marijuana-using group.Results. Marijuana-using twins significantly differed from their non-using co-twins on the general intelligence domain; however, within that domain only the performance of the block design subtest of the Wechsler Adult Intelligence Scale – Revised reached a level of statistical significance.Conclusions. Out of the numerous measures that were administered, only one significant difference was noted between marijuana-using twins and their non-using co-twins on cognitive functioning. The results indicate an absence of marked long-term residual effects of marijuana use on cognitive abilities.
Psychological distress and negative appraisals in survivors of severe acute respiratory syndrome (SARS)
Authors: CHENG S. K. W. , WONG C. W. , TSANG J. , WONG K. C. 
Published: October 2004

Background. Severe acute respiratory syndrome (SARS) is a novel disease. The authors have limited knowledge of its impact on mental health. The present study aimed to examine the level and extent of psychological distress of SARS survivors following 1-month recovery, to explore patients' negative appraisals of the impact of SARS, and to evaluate the associations between psychological distress and negative appraisals.Method. The Beck Anxiety Inventory, the Beck Depression Inventory, and a newly developed measure, the SARS Impact Scale (SIS), were mailed to 453 Hong Kong Chinese SARS survivors discharged from hospital for 4 weeks or more.Results. A total of 425 patients received the questionnaires and 180 (mean age 36·9 years; 120 women) gave valid replies. The response rate was 42·4%. The participants also represented 13·6% of all adult survivors in Hong Kong. About 35% of respondents reported ‘moderate to severe’ or ‘severe’ ranges of anxiety and/or depressive symptoms. It was found that those working as healthcare workers or having family members killed by SARS were more prone to develop subsequent high levels of distress. Factor analyses extracted three meaningful factors of the SIS, namely ‘survival threat’, ‘physical impact’, and ‘social impact’. Negative appraisals at the acute phase and 1-month recovery significantly accounted for substantial portions of variances for anxiety and depressive symptoms, after the effects of other psychosocial variables were controlled.Conclusions. Psychological distress of SARS survivors at 1-month recovery is real and significant. Negative appraisals may play a pivotal role in the development of psychological distress for SARS survivors, at least in the short term.
Genetic and environmental influences on the association between smoking and panic attacks in females: a population-based twin study
Authors: REICHBORN-KJENNERUD TED , RØYSAMB ESPEN , TAMBS KRISTIAN , TORGERSEN SVENN , KRINGLEN EINAR , MAGNUS PER , HARRIS JENNIFER R. 
Published: October 2004

Background. Clinical and epidemiological studies have reported an association between lifetime cigarette-smoking and panic attacks. Several explanations for this relationship have been proposed, mostly focusing on direct causal pathways. The objective of this study was to investigate a hypothesis of shared vulnerability by examining whether panic attacks and cigarette-smoking share genetic or environmental liability factors.Method. Questionnaire data on 3172 female–female twins (1409 complete pairs), aged 18–31 years, from a population-based Norwegian twin registry, were used to calculate the correlation between genetic factors and the correlation between environmental factors that influence lifetime measures of panic attacks and daily smoking.Results. The best-fitting biometrical twin model suggested that genetic factors influencing panic and smoking were uncorrelated. Shared or familial environmental factors were perfectly correlated, and accounted for 75% of the association between the phenotypes. The correlation between individual environmental factors influencing the phenotypes was 0·25 (0·07–0·44). In the full model, the genetic correlation was 0·17 (0·00–1·00), and genetic and shared environmental factors respectively accounted for 18% and 61% of the co-variance between panic and smoking.Conclusion. The results suggest that panic attacks and lifetime smoking have few or no genetic liability factors in common. The shared environmental factors that influence the two phenotypes are identical. Liability to panic attacks in females appears to be more influenced by shared environmental factors than previously indicated by univariate studies.
A twin study of genetic and environmental influences on tobacco initiation, regular tobacco use and nicotine dependence
Authors: MAES HERMINE H. , SULLIVAN PATRICK F. , BULIK CYNTHIA M. , NEALE MICHAEL C. , PRESCOTT CAROL A. , EAVES LINDON J. , KENDLER KENNETH S. 
Published: October 2004

Background. Numerous twin studies have reported significant genetic contributions to the variability of tobacco initiation (TI), while fewer studies have shown similar results for the persistence of smoking behavior, or nicotine dependence (ND). As the development of ND requires regular tobacco use (RTU) which in turn requires TI, a conditional approach is necessary.Method. We used structural equation modeling of multi-step conditional processes to examine the relationship between genetic and environmental risk factors for TI, RTU and ND. The tobacco variables were assessed by personal interview in female, male and opposite-sex twin pairs from the population-based Virginia Twin Registry.Results. The results suggested that the liabilities to TI, RTU and ND were correlated. Over 80% of the variance in liability to TI and RTU were shared, and a smaller proportion was shared between RTU and ND. The heritabilities were estimated at 75%, 80% and 60% respectively for TI, RTU and ND. The variance specific to liability to RTU was entirely accounted for by additive genetic factors. Only a modest part of the heritability in liability of ND was due to genetic factors specific to ND. Shared environmental factors were not significant. No sex differences were found for the sources of variation or causal paths, but prevalences were significantly greater in males versus females.Conclusions. This study showed significant overlap in the contribution of genetic factors to individual differences in TI, RTU and ND. Furthermore, there was evidence for significant additional genetic factors specific to RTU and ND.
Level of family dysfunction and genetic influences on smoking in women
Authors: KENDLER KENNETH S. , AGGEN STEVEN H. , PRESCOTT CAROL A. , JACOBSON KRISTEN C. , NEALE MICHAEL C. 
Published: October 2004

Background. An adoption study of alcoholism suggests that in women, the impact of genetic risk factors become greater in the presence of conflict in the family of origin. Is the same true for cigarette smoking (CS)?Method. We obtained, in a sample of 1676 twins from female–female twin pairs from a population-based register, a measure of maximum lifetime CS (divided into six ordinal categories) and family dysfunction (FD) assessed as the mean report of up to four informants (twin, co-twin, mother, father). Statistical analysis was conducted by traditional regression analysis and a moderator structural equation twin model using the computer program Mx.Results. With increasing levels of FD, maximum CS increased substantially while correlations for CS in monozygotic (MZ) and dizygotic (DZ) twins decreased modestly. Regression analyses demonstrated reduced twin-pair resemblance for CS with increasing levels of FD. The best-fit structural equation model found high levels of heritability for CS and no evidence for a role of shared environment. With increasing levels of FD, the proportion of variance in CS due to genetic factors (i.e. heritability) decreased while that due to unique environmental effects increased.Conclusions. Several different statistical methods suggested that, contrary to prediction, heritability of CS decreased rather than increased with higher levels of dysfunction in the family of origin. The hypothesis that genetic effects for psychiatric and drug-use disorders become stronger in more adverse environments is not universally true.
Expanding our understanding of the relationship between negative life events and depressive symptoms in black and white adolescent girls
Authors: FRANKO DEBRA L. , STRIEGEL-MOORE RUTH H. , BROWN KATHLEEN M. , BARTON BRUCE A. , McMAHON ROBERT P. , SCHREIBER GEORGE B. , CRAWFORD PATRICIA B. , DANIELS STEPHEN R. 
Published: October 2004

Background. Little is known about the extent to which negative life events predict depressive symptoms in ethnically diverse groups or whether this relationship is proximal or enduring.Method. The relationship between negative life events in adolescence and depressive symptoms in young adulthood was studied in a sample of over 1300 black and white female adolescents. Five domains of life events were assessed at age 16 years and depressive symptoms were measured at age 18 and again at age 21 years. Questions of interest included whether the association continued over time and whether there were specific domains of life events that predicted symptoms better than others.Results. The total number of negative life events at time 1 predicted depressive symptoms at both time 2 and time 3. Interpersonal loss events and other adversities, however, predicted depressive symptoms only at time 2, whereas at time 3, only interpersonal trauma was a significant predictor. No ethnic differences were found, indicating that the relationship between life events and depressive symptoms appears to be similar for black and white adolescent girls.Conclusions. The results suggest that negative life events and some specific type of stressors increase the likelihood of the onset of depression symptoms in future years, for both black and white girls. Early preventive efforts should be directed at adolescents who experience loss due to death of a significant other, traumatic events, and psychosocial adversities to forestall the development of depressive symptoms.
NMR and molecular dynamics studies of the interaction of melatonin with calmodulin
Authors: Turjanski Adrián G. , Estrin Darío A. , Rosenstein Ruth E. , McCormick John E. , Martin Stephen R. , Pastore Annalisa , Biekofsky Rodolfo R. , Martorana Vincenzo 
Published: October 2004

AbstractPineal hormone melatonin (N‐acetyl‐5‐methoxytryptamine) is thought to modulate the calcium/calmodulin signaling pathway either by changing intracellular Ca2+ concentration via activation of its G‐protein–coupled membrane receptors, or through a direct interaction with calmodulin (CaM). The present work studies the direct interaction of melatonin with intact calcium‐saturated CaM both experimentally, by fluorescence and nuclear magnetic resonance spectroscopies, and theoretically, by molecular dynamics simulations. The analysis of the experimental data shows that the interaction is calcium‐dependent. The affinity, as obtained from monitoring 15N and 1H chemical shift changes for a melatonin titration, is weak (in the millimolar range) and comparable for the N‐ and C‐terminal domains. Partial replacement of diamagnetic Ca2+ by paramagnetic Tb3+ allowed the measurement of interdomain NMR pseudocontact shifts and residual dipolar couplings, indicating that each domain movement in the complex is not correlated with the other one. Molecular dynamics simulations allow us to follow the dynamics of melatonin in the binding pocket of CaM. Overall, this study provides an example of how a combination of experimental and theoretical approaches can shed light on a weakly interacting system of biological and pharmacological significance.
Position dependence of the 13C chemical shifts of α‐helical model peptides. Fingerprint of the 20 naturally occurring amino acids
Authors: Vila Jorge A. , Baldoni Héctor A. , Scheraga Harold A. 
Published: October 2004

AbstractThe position dependence of the 13C chemical shifts was investigated at the density functional level for α‐helical model peptides represented by the sequence Ac‐(Ala)i‐X‐(Ala)j‐NH2, where X represents any of the 20 naturally occurring amino acids, with 0 ≤ i ≤ 8 and i + j = 8. Adoption of the locally dense basis approach for the quantum chemical calculations enabled us to reduce the length of the chemical‐shift calculations while maintaining good accuracy of the results. For the 20 naturally occurring amino acids in α‐helices, there is (1) significant variability of the computed 13C shielding as a function of both the guest residue (X) and the position along the sequence; for example, at the N terminus, the 13Cα and 13Cβ shieldings exhibit a uniform pattern of variation with respect to both the central or the C‐terminal positions; (2) good agreement between computed and observed 13Cα and 13Cβ chemical shifts in the interior of the helix, with correlation coefficients of 0.98 and 0.99, respectively; for 13Cα chemical shifts, computed in the middle of the helix, only five residues, namely Asn, Asp, Ser, Thr, and Leu, exhibit chemical shifts beyond the observed standard deviation; and (3) better agreement for four of these residues (Asn, Asp, Ser, and Thr) only for the computed values of the 13Cα chemical shifts at the N terminus. The results indicate that 13Cβ, but not 13Cβ, chemical shifts are sensitive enough to reflect the propensities of some amino acids for specific positions within an α‐helix, relative to the N and C termini of peptides and proteins.
EFFECTS OF SALINITY ON THE DISTRIBUTION OF CALOGLOSSA LEPRIEURII (RHODOPHYTA) IN THE BRISBANE RIVER, AUSTRALIA1
Authors: Mosisch Thorsten D. 
Published: October 2004

ABSTRACTThe role of salinity as a factor determining the distribution of two red algal taxa, Caloglossa leprieurii (Mont.) J. Ag. var. leprieurii and Caloglossa leprieurii var. angusta Jao, along the course of the Brisbane River, Queensland, Australia, was investigated. In the field, C. leprieurii var. angusta tolerated a narrower salinity range (mean salinity = 0.0–18.9) than C. leprieurii var. leprieurii (mean salinity = 2.0–33.8) and occupied areas of lower salinity (salinity expressed according to the Practical Salinity Scale of 1978). Both taxa coexisted for a distance of 23 km along the middle reaches of the river. Cell measurements of specimens of both taxa collected along the river showed an increase in cell sizes upstream from the mouth. Results of a reciprocal transplant experiment and growth responses in a series of laboratory culture studies of the two taxa in a range of salinities are presented. These could be correlated with the field distribution of the algae, demonstrating their euryhalinity and the presence of distinct salinity ecotypes.
PRODUCTION OF HYALINE HAIRS BY INTERTIDAL SPECIES OF FUCUS (FUCALES) AND THEIR ROLE IN PHOSPHATE UPTAKE1
Authors: Hurd Catriona L. , Galvin Robert S. , Norton Trevor A. , Dring Matthew J. 
Published: October 2004

ABSTRACTA field study to determine the precise times of year at which three intertidal species of Fucus start to produce hyaline hairs and cease producing such hairs was conducted on the Isle of Man, U.K. Hairs were first observed during February, and within 6 days of their initial appearance, all tagged plants of all species at all tidal heights on the shore possessed hairs. Hair production continued until the beginning of October, at which time Fucus plants growing at the lowest stations (+ 3.0 m) had glabrous apical growth. Hair production continued later into the year for plants growing higher on the shore, and it was not until mid‐November that glabrous apical growth was observed in all plants.Phosphate uptake rates of pilose (hairy) and glabrous (hairless) apical sections were measured in November 1988 for F. spiralis L. and in January 1989 for F. spiralis and F. serratus L., at phosphate concentrations ranging from 0.8 μM (ambient seawater) to 9.0 μM. In ambient seawater, pilose plants of F. spiralis removed phosphate 2–3 times faster than glabrous plants, whereas the uptake rates of pilose plants of F. serratus were about 50% greater than those of glabrous plants. The differences between uptake rates of pilose and glabrous plants of both species were smaller or nonsignificant at higher phosphate concentrations. The field and laboratory data are consistent with the hypothesis that hairs are formed in Fucus as a response to increased nutrient demand and that hairs facilitate the uptake of nutrients from seawater at concentrations typical of natural situations.
INHIBITORY EFFECTS OF CONCANAVALIN A AND TUNICAMYCIN ON SEXUAL ATTACHMENT OF ALEXANDRIUM CATENELLA (DINOPHYCEAE)1
Authors: Sawayama Shigeki , Sako Yoshihiko , Ishida Yuzaburo 
Published: October 2004

ABSTRACTThe effect of concanavalin A (a lectin) and tunicamycin (an inhibitor of protein glycosylation) on sexual attachment of gamete pairs of the dinoflagellate Alexandrium catenella Whedon & Kofoid was studied. Concanavalin A inhibited sexual attachment at a concentration of 0.005%, and this inhibition was released by the addition of glucose or mannose at 10 mM. Mating type plus cells of A. catenella treated with tunicamycin for 12 h were not capable of sexual attachment. These results are the first to suggest the existence of a cell–cell recognition system in sexual attachment in A. catenella.
TWO DISTINCT SMALL‐SUBUNIT RIBOSOMAL RNA GENES IN THE NORTH AMERICAN TOXIC DINOFLAGELLATE ALEXANDRIUM FUNDYENSE (DINOPHYCEAE)1
Authors: Scholin Christopher A. , Anderson Donald M. , Sogin Mitchell L. 
Published: October 2004

ABSTRACTTwo distinct small‐subunit ribosomal RNA genes, termed the A gene and B gene, were detected in a clonal isolate of the toxic dinoflagellate, Alexandrium fundyense Balech. The two sequences, which occur in roughly a 1:1 ratio in polymerase chain reaction‐amplified material, differ at approximately 40 positions scattered throughout the length of the molecule. Transcripts of the B sequence were not detected in total RNA extracts from nutrient‐replete and ammonium‐starved (sexually induced) cultures or nutrient‐replete log‐phase cultures harvested at 2‐h intervals over a complete circadian cycle. Many of the position changes in the B gene deviate from universally and eukaryotic‐conserved small‐subunit rRNA sequences. In contrast, the A gene is expressed under all culture conditions tested and does not violate any conserved sequence positions. Thus, the B sequence is not represented by stable transcripts and is likely a pseudogene. The B gene may serve as a useful marker for fine‐scale population and taxonomic analyses of some Alexandrium species.
THE CALCAREOUS RESTING CYST OF PENTAPHARSODINIUM TYRRHENICUM COMB. NOV. (DINOPHYCEAE)1
Authors: Montresor Marina , Zingone Adriana , Marino Donato 
Published: October 2004

ABSTRACTWhile investigating dinoflagellate cyst assemblages in surface sediments of the Gulfs of Naples and Salerno (Mediterranean Sea), we found a new calcareous resting cyst. This cyst has a round to oval body surrounded by a thick mineral layer, which gives it the shape of a Napoleon hat, with a flat, oval face bearing the archeopyle and a convex keel on the opposite side. The cyst shape is variable in both natural samples and clonal cultures. The organic membrane underlying the calcareous covering is resistant to acetolysis, thus demonstrating the presence of sporopolleninlike material. The cyst germinated into a motile stage having the same morphological features and thecal plate pattern as Peridinium tyrrhenicum Balech. We believe the validity of the genus Pentapharsodinium Indelicato & Loeblich should be accepted. Based on the comparative examination of the species we collected and of a similar species, Pentapharsodinium trachodium Indelicato & Loeblich, we propose Pentapharsodinium tyrrhenicum as a new combination for Peridinium tyrrhenicum.The genus Pentapharsodinium also includes P. dalei Indelicato & Loeblich (= Peridinium faeroense Dale), which produces spiny, organic‐walled cysts. The presence of species forming calcareous cysts and species producing noncalcareous cysts in the same genus raises questions about maintaining the family Calciodinellaceae. This family should only include calcareous cyst‐forming peridinioids, in order to maintain a unified system of classification of fossil and recent dinoflagellates.
DISTRIBUTION AND SYSTEMATICS OF THE FRESHWATER GENUS SIRODOTIA(BATRACHOSPERMALES, RHODOPHYTA) IN NORTH AMERICA1
Authors: Necchi Orlando , Sheath Robert G. , Cole Kathleen M. 
Published: October 2004

ABSTRACTMultivariate morphometrics and image analysis were used to determine the number of well‐delineated infrageneric taxa of Sirodotia in North America. Three groupings were distinguished from 25 populations examined from Newfoundland and Quebec in the north to central Mexico in the south. These groupings were statistically related to 10 type specimens, and the following species were recognized: Sirodotia huillensis (Welwitsch ex W. et G. S. West) Skuja (syn. S. ateleia Skuja), S. suecica Kylin (syn. S. acuminata Skuja ex Flint and S. fennica Skuja), and S. tenuissima (Collins) Skuja ex Flint. These species are differentiated on the basis of whorl shape and degree of separation at maturity (S. suecica, rounded and appressed; S. huillensis and S. tenuissima, truncated apex and separated), the density of spermatangia (S. huillensis, dense clusters; S. suecica and S. tenuissima, sparsely aggregated), and the mode of germination of the gonimoblast initial (S. suecica and S. tenuissima, from the nonprotuberant side of the fertilized carpogonium; S. huillensis from the protuberant side). Sirodotia huillensis was found only in the desert‐chaparral, whereas S. suecica and S. tenuissima occurred from south‐temperate to boreal regions in cool (temperature 8–18° C), low ion (specific conductance 10–99 μS · cm−1), and mildly acidic to neutral (pH 5.7–7.3) waters.
GEL PURIFICATION OF RED ALGAL GENOMIC DNA: AN INEXPENSIVE AND RAPID METHOD FOR THE ISOLATION OF POLYMERASE CHAIN REACTION‐FRIENDLY DNA1
Authors: Saunders Gary W. 
Published: October 2004

ABSTRACTA simplified approach for the extraction of DNA from red algae in presented. Procedures are simple and fast, requiring a minimum of reagents and apparatus. The method involves an initial lysis step followed by an optional phenol/chloroform extraction. The final gel‐purification step removes polymerase chain reaction‐inhibiting polysaccharides from the DNA preparation. DNA is extracted as easily from dried algae as it is from snap‐frozen, fresh material, thus greatly facilitating the collection and transport of algal samples.