bluuebunny/crossref_metadata_2025 huggingface dataset:
Heats of Reaction from Hartree—Fock Energies of Closed-Shell Molecules
Authors: Snyder Lawrence C.
Published: January 2005

If correlation energy were conserved in chemical reactions having only closed-shell reactants and products, then molecular Hartree—Fock energies could be employed to compute standard heats of reaction. This possibility is here explored by the computation of theoretical heats of reaction for all gas-phase reactions of molecules for which Hartree—Fock energies are available. For the formation of two moles of HF, the theoretical and experimental heats of reaction differ by 16 kcal. The sum of the correlation energies of H2 and F2 is apparently greater than in two HF molecules. For five other reactions examined, the theoretical and experimental heats of reaction differed by 11 kcal or less. Conversely, thermochemical data are combined with known Hartree—Fock energies to predict the Hartree—Fock energies of methane, water, and ammonia. It is concluded that the theoretical prediction of standard heats of reaction to an accuracy of 2 kcal/mole will require a semiquantitative prediction of the change in correlation energy.
Electron Spin Resonance of X-Irradiated Valines
Authors: Shields Howard , Hamrick Phillip , DeLaigle Dean
Published: January 2005

X-irradiation of single crystals of dl-valine, d-valine, and l-valine produce free radicals which are identified as (CH3)2ĊCH(+NH3)COO−. These single-crystal studies show that the radical in dl-valine is not (CH3)2ĊCH2COOH as reported earlier [S. Z. Shul'ga and A. I. Telyatmik, Ukrayin. Fiz. 9, 185 (1964)]. Spectra resulting from an equal interaction of the unpaired electron with the protons of the two methyl groups consist of seven main components. Each of these seven components is split into equal triplets by an interaction with the 14N nucleus of the amino group. The origin of the triplet splitting was verified by examining a sample enriched to about 50% with 15N. At some orientations coupling with the β proton can be resolved. The maximum observed β-proton coupling was 4 G. The principal values of the methyl group proton hyperfine coupling constants are (in gauss) 24.4, 23.2, and 22.4. Principal values for the 14N hyperfine coupling constants are (in gauss) 9.0, 7.3, and 6.9.
Annexin 2 Promotes the Formation of Lipid Microdomains Required for Calcium-regulated Exocytosis of Dense-Core Vesicles
Authors: Chasserot-Golaz Sylvette , Vitale Nicolas , Umbrecht-Jenck Emeline , Knight Derek , Gerke Volker , Bader Marie-France
Published: January 2005

Annexin 2 is a calcium-dependent phospholipid-binding protein that has been implicated in a number of membranerelated events, including regulated exocytosis. In chromaffin cells, we previously reported that catecholamine secretion requires the translocation and formation of the annexin 2 tetramer near the exocytotic sites. Here, to obtain direct evidence for a role of annexin 2 in exocytosis, we modified its expression level in chromaffin cells by using the Semliki Forest virus expression system. Using a real-time assay for individual cells, we found that the reduction of cytosolic annexin 2, and the consequent decrease of annexin 2 tetramer at the cell periphery, strongly inhibited exocytosis, most likely at an early stage before membrane fusion. Secretion also was severely impaired in cells expressing a chimera that sequestered annexin 2 into cytosolic aggregates. Moreover, we demonstrate that secretagogue-evoked stimulation triggers the formation of lipid rafts in the plasma membrane, essential for exocytosis, and which can be attributed to the annexin 2 tetramer. We propose that annexin 2 acts as a calcium-dependent promoter of lipid microdomains required for structural and spatial organization of the exocytotic machinery.
The Rate-limiting Enzyme in Phosphatidylcholine Synthesis Regulates Proliferation of the Nucleoplasmic Reticulum
Authors: Lagace Thomas A. , Ridgway Neale D.
Published: January 2005

The nucleus contains a network of tubular invaginations of the nuclear envelope (NE), termed the nucleoplasmic reticulum (NR), implicated in transport, gene expression, and calcium homeostasis. Here, we show that proliferation of the NR, measured by the frequency of NE invaginations and tubules, is regulated by CTP:phosphocholine cytidylyltransferase-α (CCTα), the nuclear and rate-limiting enzyme in the CDP–choline pathway for phosphatidylcholine (PtdCho) synthesis. In Chinese hamster ovary (CHO)-K1 cells, fatty acids triggered activation and translocation of CCTα onto intranuclear tubules characteristic of the NR. This was accompanied by a twofold increase in NR tubules quantified by immunostaining for lamin A/C or the NE. CHO MT58 cells expressing a temperature-sensitive CCTα allele displayed reduced PtdCho synthesis and CCTα expression and minimal proliferation of the NR in response to oleate compared with CHO MT58 cells stably expressing CCTα. Expression of CCTα mutants in CHO58 cells revealed that both enzyme activity and membrane binding promoted NR proliferation. In support of a direct role for membrane binding in NR tubule formation, recombinant CCTα caused the deformation of liposomes into tubules in vitro. This demonstrates that a key nuclear enzyme in PtdCho synthesis coordinates lipid synthesis and membrane deformation to promote formation of a dynamic nuclear-cytoplasmic interface.
The Yeast Endosomal Na+(K+)/H+Exchanger Nhx1 Regulates Cellular pH to Control Vesicle Trafficking
Authors: Brett Christopher L. , Tukaye Deepali N. , Mukherjee Sanchita , Rao Rajini
Published: January 2005

The relationship between endosomal pH and function is well documented in viral entry, endosomal maturation, receptor recycling, and vesicle targeting within the endocytic pathway. However, specific molecular mechanisms that either sense or regulate luminal pH to mediate these processes have not been identified. Herein we describe the use of novel, compartment-specific pH indicators to demonstrate that yeast Nhx1, an endosomal member of the ubiquitous NHE family of Na+/H+exchangers, regulates luminal and cytoplasmic pH to control vesicle trafficking out of the endosome. Loss of Nhx1 confers growth sensitivity to low pH stress, and concomitant acidification and trafficking defects, which can be alleviated by weak bases. Conversely, weak acids cause wild-type yeast to present nhx1Δ trafficking phenotypes. Finally, we report that Nhx1 transports K+in addition to Na+, suggesting that a single mechanism may responsible for both pH and K+-dependent endosomal processes. This presents the newly defined family of eukaryotic endosomal NHE as novel targets for pharmacological inhibition to alleviate pathological states associated with organellar alkalinization.
Serum antibodies to collagen XIII: a further good marker of active Graves’ ophthalmopathy
Authors: De Bellis A. , Sansone D. , Coronella C. , Conte M. , Iorio S. , Perrino S. , Battaglia M. , Bellastella G. , Wall J. R. , Bellastella A. , Bizzarro A.
Published: January 2005

objective  In Graves’ ophthalmopathy (GO) intercellular adhesion molecule‐1 (ICAM‐1) is thought to play a key role in lymphocyte infiltration into the orbit, and serum levels of its soluble form are positively correlated to clinical activity score (CAS). Serum antibodies against collagen XIII (CollXIIIAb), a plasma membrane protein expressed at a low level in almost all connective tissue‐producing cells, have been detected in GO, but their significance is unclear. The aim of this study was to search for CollXIIIAb in Graves’ patients with and without ophthalmopathy and to correlate their levels with CAS and with serum soluble ICAM‐1 (sICAM‐1) values.

patients  We studied 66 patients with Graves’ disease whose sera had been previously tested for sICAM‐1 levels, grouped as follows: 28 with moderate and active ophthalmopathy (group 1), 12 of them hyperthyroid (group 1a) and 16 euthyroid (group 1b); 13 with mild and inactive ophthalmopathy and normal thyroid function (group 2); 25 without ophthalmopathy (group 3), 11 of them hyperthyroid (group 3a) and 14 euthyroid (group 3b). Finally, 26 sera of normal controls were studied.

measurements  CollXIIIAb were evaluated by an enzyme‐linked immunosorbent assay (ELISA) method.

results  In group 1 patients, CollXIIIAb were detected at high levels in 8/12 (66·6%) in group 1a [optical density (OD) ranging from 0·529 to 0·894] and in 10/16 (62·5%) in group 1b (OD 0·560–0·855). In group 2 patients, CollXIIIAb were detected but at low levels (OD 0·205–0·260) in 4/13 patients (30·7%). In group 3 patients, CollXIIIAb were present at low levels in 6/11 (54·5%) of group 3a and in 5/14 (35·7%) of group 3b (OD 0·215–0·290 and 0·144–0·245, respectively). CollXIIIAb were detected in only 4/26 normal controls (15%) but at low levels (OD 0·150–0·185). CollXIIIAb values in both groups 1a and 1b were significantly higher than those of the remaining groups. A positive correlation between CollXIIIAb levels and CAS but not thyroid hormone levels was found in groups 1a, 1b and 2. Moreover, a positive correlation between CollXIIIAb levels and sICAM‐1‐values was also evidenced in all three groups.

conclusions  Our results suggest that CollXIIIAb could be considered as a further good marker of active inflammatory processes involving the adipose connective tissue in GO. In particular, the high levels of CollXIIIAb in sera of Graves’ patients with active ophthalmopathy could reflect an increased expression of type XIII collagen on the membrane of activated fibroblasts in these patients. Thus, the evaluation of these antibodies could be added to other known markers as a useful and inexpensive tool in monitoring Graves’ patients and in modulating the treatment of GO.
Ghrelin and adiponectin in patients with Cushing's disease before and after successful transsphenoidal surgery
Authors: Libè Rossella , Morpurgo Paola Silvia , Cappiello Vincenzo , Maffini Antonia , Bondioni Sara , Locatelli Marco , Zavanone Mario , Beck‐Peccoz Paolo , Spada Anna
Published: January 2005

background  Ghrelin, an endogenous ligand of the GH secretagogue receptor that exerts orexigenic activity, is negatively correlated with body mass index (BMI) and insulin resistance. Conversely, low levels of adiponectin (ApN), a circulating adipocytokine with antidiabetic, antiatherogenic and anti‐inflammatory properties, have been found in several insulin‐resistant conditions. Although Cushing's syndrome causes several metabolic and hormonal changes leading to insulin resistance and central obesity, few data concerning the impact of glucocorticoid excess on ghrelin and ApN levels are so far available.

design  We evaluated ghrelin and ApN levels in 14 women (age ± SE 39·5 ± 3·9 years, BMI ± SE 25·8 ± 1·4 kg/m2) with Cushing's disease (CD) at baseline and after successful transsphenoidal surgery (TSS) and in 14 age‐ and BMI‐matched healthy women.

results  Despite similar levels of fasting glucose, insulin, homeostatic model assessment‐estimated insulin resistance (HOMA‐IR) and quantitative insulin sensitivity check index (QUICKI) values, patients with CD had ghrelin levels lower than controls (117·8 ± 21·5 vs. 269·6 ± 51·4 pmol/l, P < 0·01), and ghrelin levels did not correlate with ACTH, cortisol, androgen and GH levels. Patients and controls showed similar ApN levels (11·1 ± 1·6 vs. 11·5 ± 2·0 mg/l), which correlated negatively with insulin, HOMA‐IR and BMI and positively with QUICKI and high density lipoprotein (HDL)‐cholesterol only in controls. At 10·2 ± 0·7 months after successful TSS, patients showed a significant increase in ghrelin levels compared to pretreatment values (342·5 ± 25·6 vs. 117·8 ± 21·5 pmol/l, P < 0·005) along with significant modifications in BMI, insulin, HOMA‐IR and HDL‐cholesterol and no change in ApN levels. In two patients tested on days 2–4 after TSS, no modification in ghrelin and ApN levels was observed, despite a dramatic reduction in cortisol levels.

conclusion  Cortisol excess did not directly affect ghrelin and ApN levels in patients with CD. The observation that ghrelin levels were low during the active phase of CD and increased after recovery suggests that glucocorticoids may influence ghrelin levels indirectly by modulating adiposity and metabolic signals over the long term.
Increased levels of serum advanced glycation end‐products in women with polycystic ovary syndrome
Authors: Diamanti‐Kandarakis Evanthia , Piperi Christina , Kalofoutis Anastasios , Creatsas George
Published: January 2005

objective  Women with polycystic ovary syndrome (PCOS) carry a number of cardiovascular risk factors and are considered to be at increased risk for atherosclerosis. Elevated concentrations of advanced glycation end‐products (AGE), which exert their effects through interaction with specific receptors (RAGE), have been implicated in the cellular and tissue damage during atherosclerotic processes.

design/patients  We investigated serum AGE levels in 29 young women with PCOS as well as the expression of their receptor, RAGE, in circulating monocytes and compared them levels with 22 healthy control women.

measurements/results  Women with PCOS had higher levels of serum AGE proteins compared to healthy individuals (9·81 ± 0·16 vs. 5·11 ± 0·16, P < 0·0001), and increased RAGE expression was observed in monocytes of PCOS women compared to controls (30·91 ± 10·11 vs. 7·97 ± 2·61, P < 0·02). A positive correlation was observed between AGE proteins and testosterone (T) levels (r = 0·73, P < 0·0001). The correlation between AGE proteins and T levels remained high (partial correlation coefficient = 0·61, P = 0·0001) after controlling for body mass index (BMI), insulin levels and the area under the curve for glucose (AUCGLU) during an oral glucose tolerance test (OGTT). A positive correlation was also observed between AGE proteins and the free androgen index (FAI) (r = 0·58, P < 0·0001), waist‐to‐hip ratio (WHR) (r = 0·31, P < 0·02), insulin (r = 0·46, P < 0·001), homeostasis model assessment (HOMA) (r = 0·47, P < 0·0001), AUCGLU (r = 0·52, P < 0·002) and RAGE (r = 0·59, P < 0·01). A negative correlation was observed between AGE proteins and glucose/insulin ratio (GLU/INS) (r = −0·35, P < 0·01), and the quantitative insulin sensitivity check index (QUICKI) (r =−0·50, P < 0·01). In multiple regression analysis T was the only independent predictor of AGE levels (P < 0·0001, b = 0·044) between BMI, insulin, SHBG and AUCGLU (adjusted R2 = 0·59, F = 44·41, P < 0·0001).

conclusion  These data clearly demonstrate, for the first time, that PCOS women without overt hyperglycaemia have increased AGE levels and elevated RAGE expression when compared with controls.
Androgen receptor gene expression in leucocytes is hormonally regulated: implications for gender differences in disease pathogenesis
Authors: Sader Mark A. , McGrath Kristine C. Y. , Hill Michelle D. , Bradstock Ken F. , Jimenez Mark , Handelsman David J. , Celermajer David S. , Death Alison K.
Published: January 2005

Objective  There is evidence that male sex hormones influence the rate of progression of inflammatory and cardiovascular diseases. We have previously shown that human leucocytes and arterial cells isolated from male donors express more androgen receptor (AR) than those from female cells, with potentially pro‐atherogenic effects. We now investigate whether the gender difference in AR expression is due to genetic or hormonal regulation.

Design and Patients  The influence of hormones on AR expression were studied in hpg mice (a mouse model of androgen deficiency) treated with testosterone, oestradiol or dihydrotestosterone (DHT). Blood samples were obtained for leucocyte AR expression and hormone levels from 53 subjects, grouped into: 12 male [six young adult (27–45 years), six elderly (71–79 years)] and six female (young adult 25–45 years) healthy controls; six male‐to‐female transsexuals (M2F; 20–50 years) receiving stable pharmacological oral oestrogen treatment; six female‐to‐male transsexuals (F2M; 31–51 years) receiving stable androgen replacement therapy; five younger men (18–56 years) who had been receiving long‐term androgen replacement therapy for hypogonadal disease; six elderly men (72–88 years) who had undergone medical castration for prostate cancer treatment; and 12 male bone marrow transplant recipients (BMT; 23–65 years) from either male or female donors.

Measurements  Serum testosterone and oestradiol concentrations were measured by established immunoflurometric assays from unextracted human serum. AR mRNA levels were measured by RT–PCR and AR protein levels by western blot (cell culture) or immunohistochemistry (mouse arteries).

Results  We found that AR mRNA levels were significantly down‐regulated in the leucocytes of hpg mice that were treated with exogenous testosterone, oestradiol or DHT. AR protein levels were also lower in aortic tissue from the same mice. In humans, we found AR expression was significantly down‐regulated by exogenous treatment with testosterone in F2M (31 ± 13%, compared with control) or oestradiol in M2F (22 ± 5%) but was significantly up‐regulated by endogenous testosterone in BMT (128 ± 17%). Low androgen levels measured in castrated older men were associated with markedly increased AR expression (207 ± 26%, P < 0·05) compared with age‐matched older male controls (100 ± 2%).

Conclusions  Our results indicate a regulated ability of vascular cells to respond to sex hormones, with the effects of exogenous therapies differing markedly from those due to endogenous sex hormones. We conclude that the gender difference in AR expression in vascular cells is hormonally, rather than genetically, controlled.
Ageing and plasma adiponectin concentration in apparently healthy males and females
Authors: Adamczak Marcin , Rzepka Ewa , Chudek Jerzy , Wiȩcek Andrzej
Published: January 2005

Objective  It is well known that ageing is associated with several hormonal alterations. However, the consequence of ageing on the endocrine function of adipose tissue is not fully elucidated. Adiponectin is a new anti‐inflammatory protein secreted exclusively by adipocytes and plays a protective role against insulin resistance and atherosclerosis. Therefore, the aim of present study was to estimate plasma adiponectin concentration in apparently healthy elderly subjects.

Subjects  Fifty‐eight women and 67 men aged 20–93 years were included in this study. Subjects were divided into three groups: younger than 50 years, between 50 and 70 years and older than 70 years of age.

Measurements  Plasma adiponectin concentration was estimated by an enzyme‐linked immunosorbant assay in blood samples withdrawn in the morning after overnight fasting. In males plasma testosterone and dehydroepiandrostendione sulphate concentrations were assessed by a radioimmunoassay method.

Results  Plasma adiponectin concentration only tended to be higher in all elderly subjects (above 70 years) than in the group of all subjects aged between 50 and 70 and the group younger than 50 years of age (12·8 ± 5·7; 9·9 ± 5·7 and 10·7 ± 5·4 µg/ml, respectively). Plasma adiponectin concentration was of similar magnitude in female subjects of these three groups (11·2 ± 5·7; 11·2 ± 6·8 and 11·7 ± 4·9 µg/ml, respectively). In contrast, males over 70 years old are characterized by significantly higher plasma adiponectin (14·0 ± 5·4 µg/ml) concentration than males between 50 and 70 years of age (8·9 ± 4·7 µg/ml, P < 0·01) and males younger than 50 years of age (9·6 ± 5·7 µg/ml, P < 0·05). In the entire studied group a significant but weak, positive correlation was found between plasma adiponectin concentration and age (τ = 0·12; P = 0·04). Additionally, significant correlation was found between plasma adiponectin concentration and age in males when analysed separately (τ = 0·28; P = 0·0007). Such correlation was not significant in females (τ = −0·06; P = 0·5).

Conclusions  Plasma adiponectin concentration in females did not change significantly with age. In contrast to females, elderly males over 70 years of age are characterized by significantly higher plasma adiponectin concentration than younger ones.
The process of research use in nursing
Authors: French Beverley
Published: January 2005

Aim.  This paper describes the process of research use undertaken by groups of specialist nurses involved in the construction of policy recommendations for nursing practice.

Background.  A number of prescriptive models of research use have been described in the nursing literature. Previous studies have attempted to measure the instrumental use of research findings in nursing practice. However, there is no evidence on how research use occurs, or why results differ across individuals, settings, tasks or time. There has been little investigation into the congruence of prescriptive models with the realities of research use in practice.

Method.  The study used an ethnomethodological approach to describe the practical reasoning undertaken by specialist nurses during research use. The method was participant observation with three clinical workgroups, comprising a series of meetings of practitioners from between 11 and 25 health care provider organizations. Data collected from recording discussions at the meetings were analysed using grounded data reduction, and were subject to external verification of description and inference.

Findings.  The process of research use consistently contained four stages of practical reasoning comprising research identification, confirmation, evaluation and application. Each stage involved practitioners in cognitive work to translate the research evidence into practice policy.

Conclusions.  While the process of research use described in the findings is not markedly different in outline from prescriptive models of the process available in the literature, inconsistencies are highlighted in the way the process is conceptualized. Prescriptive models of research use do not adequately reflect the task of problem‐setting, use of multiple frames of reference for evaluation, and how information from research is to be integrated with information from other sources.
Adults with autism living at home or in non‐family settings: positive and negative aspects of residential status
Authors: Krauss M. W. , Seltzer M. M. , Jacobson H. T.
Published: January 2005

Background  Very little is known about the context of caregiving by parents of adults with autism or about the perceived impacts of continued patterns of co‐residence vs. out‐of‐family living. In the present study, maternal assessments of residential status, involvement with adult children living in a non‐family setting, and the impacts on mothers of their residential arrangements were examined.

Methods  Mothers from 133 families of adults (aged 22 years and older) with autism spectrum disorder (ASD) completed questionnaires as part of a longitudinal study on family caregiving. Mothers completed open‐ended questions regarding the positive and negative aspects of their child's residential arrangement. Mothers also completed scaled questions regarding their satisfaction with their child's residential arrangement, the different ways in which people's lives change after a relative moves from the home, and the frequency of contact with their son or daughter.

Results  Mothers found co‐residing with their adult child to be of greatest positive benefit to the family while those living apart found this residential arrangement of greatest benefit to the son or daughter with ASD. The greatest negative consequences for co‐residing mothers were understood to fall on families, while mothers felt the majority of negative consequences for those that lived apart. There was a high level of contact and maternal involvement between the mother and adult child with ASD even after out‐of‐home placement.

Conclusions  Residential status, as appraised by mothers, has varying impacts on the individual with ASD, on the family, and on mothers as individuals and caregivers. The present analysis suggests the multifaceted and highly contingent maternal experience associated with where her child with ASD lives. Among families whose children live elsewhere, there is an impressive amount of continued contact between these families and their son/daughter.
Mathematical skills in Prader–Willi Syndrome
Authors: Bertella L. , Girelli L. , Grugni G. , Marchi S. , Molinari E. , Semenza C.
Published: January 2005

Objectives  This paper investigates mathematical skills in Prader–Willi Syndrome (PWS), a pathological condition because of congenital alterations of chromosome pair 15. The following questions were addressed: (1) Are mathematical skills in PWS relatively more impaired with respect to other cognitive functions (as has been repeatedly but anecdotally reported)?; and (2) What is the nature of the mathematical impairment?

Methods  The first study employed the Wechsler Adult Intelligence Scale (WAIS) and an extensive battery of cognitive tasks for which norms are known. Both batteries include a mathematical section. The second study used a theoretically motivated series of mathematical tasks specifically designed to individually assess the different cognitive components underlying mathematical skills.

Results  Mathematical skills were found to be the most impaired cognitive abilities together with short‐term memory capacity. No specific mathematical domain was seen to be unaffected in PWS participants. The clearest deficits observed concern ‘syntactic’ processes in number transcoding, multiplication, number facts retrieval and calculation procedures.

Conclusion  Failure of mathematical skills is the most distinctive feature in the cognitive profile of PWS. However, to determine whether this is indeed a specific pattern of performance related to PWS, results must be compared with those obtained with patients manifesting other genetic disorders.
Host-related genetic differentiation in the anther smut fungus Microbotryum violaceum in sympatric, parapatric and allopatric populations of two host species Silene latifolia and S. dioica
Authors: Van Putten W. F. , Biere A. , Van Damme J. M. M.
Published: January 2005

We investigated genetic diversity in West European populations of the fungal pathogen Microbotryum violaceum in sympatric, parapatric and allopatric populations of the host species Silene latifolia and S. dioica, using four polymorphic microsatellite loci. In allopatric host populations, the fungus was highly differentiated by host species, exhibiting high values of FST and RST, and revealed clear and distinct host races. In sympatric and parapatric populations we found significant population differentiation as well, except for one sympatric population in which the two host species grew truly intermingled. The mean number of alleles per locus for isolates from each of the host species was significantly higher in sympatric/parapatric than in allopatric populations. This suggests that either gene flow between host races in sympatry, or in case of less neutral loci, selection in a more heterogeneous host environment can increase the level of genetic variation in each of the demes. The observed pattern of host-related genetic differentiation among these geographically spread populations suggest a long-term divergence between these host races. In sympatric host populations, both host races presumably come in secondary contact, and host-specific alleles are exchanged depending on the amount of fungal gene flow.
Pollen and sperm heteromorphism: convergence across kingdoms?
Authors: Till‐Bottraud I. , Joly D. , Lachaise D. , Snook R. R.
Published: January 2005

Sperm competition theory predicts that males should produce many, similar sperm. However, in some species of animals and plants, males exhibit a heteromorphism that results in the production of at least two different types of sperm or pollen grains. In animals, sperm heteromorphism typically corresponds to the production of one fertile morph and one (or more) sterile morph(s), whereas in plants two or more pollen morphs (one of which can be either sterile or fertile) are produced in all flowers but sometimes in different anthers. Heteromorphism has arisen independently several times across phyla and at different phylogenetic levels. Here, we compare and contrast sperm and pollen heteromorphism and discuss the evolutionary hypotheses suggested to explain heteromorphism in these taxa. These hypotheses include facilitation, nutritive contribution, blocking, cheap filler, sperm flushing or killing for animals; outcrossing and precise cross‐pollen transfer or bet‐hedging strategy for plants; cryptic female choice for both. We conclude that heteromorphism in the two phyla is most likely linked to a general evolutionary response to sexual selection, either to increase one male's sperm or pollen success in competition with other males, or mediate male/female interactions. Therefore, although sperm and pollen are not homologous, we suggest that heteromorphism represents an example of convergence across kingdoms.
Reproductive value in a complex life cycle: heat tolerance of the pitcher‐plant mosquito, Wyeomyia smithii
Authors: Zani P. A. , Cohnstaedt L. W. , Corbin D. , Bradshaw W. E. , Holzapfel C. M.
Published: January 2005

Because mortality accumulates with age, Fisher proposed that the strength of selection acting on survival should increase from birth up to the age of first reproduction. Hamilton later theorized that the strength of selection acting on survival should not change from birth to age at first reproduction. As organisms in nature do not live in uniform environments but, rather, experience periodic stress, we hypothesized that resistance to environmental stress should increase (Fisher) or remain constant (Hamilton) from birth to age at first reproduction. Using the pitcher‐plant mosquito, Wyeomyia smithii, we imposed heat stress by simulating the passage of a warm‐weather front at different preadult and adult stages. Contrary to either Fisher or Hamilton, stress tolerance declined from embryos to larvae to pupae to adults. Consequently, reproductive value appears to have been of little consequence in the evolution of stage‐specific tolerance of heat stress in W. smithii.
Variation among populations ofDiodia teres(Rubiaceae) in environmental maternal effects
Authors: Hereford J. , Moriuchi K. S.
Published: January 2005

Previous studies have quantified variation in environmental maternal effects (EME) within populations, but these effects could differ among populations as well. In this study we grew clonal replicates of individuals from three populations of the annual plantDiodia teresin their native and non‐native environments. Our goal was to estimate the effects of maternal environment and maternal population on seed and seedling traits. Seeds that were produced in this field study were then planted in two soil types to quantify effects of the offspring environment on seedling traits. There was substantial variation among populations for seed weight. We found population variation for EME, and maternal environment by offspring environment interactions. We conclude that variation among populations in EME may be an unrecognized component of local adaptation, and that attempts to control maternal effects by statistically accounting for variation in seed weight may be ineffective.
Evolutionary divergence and possible incipient speciation in post‐glacial populations of a cosmopolitan aquatic plant
Authors: Nies G. , Reusch T. B. H.
Published: January 2005

Habitat configuration is expected to have a major influence on genetic exchange and evolutionary divergence among populations. Aquatic organisms occur in two fundamentally different habitat types, the sea and freshwater lakes, making them excellent models to study the contrasting effects of continuity vs. isolation on genetic divergence. We compared the divergence in post‐glacial populations of a cosmopolitan aquatic plant, the pondweed Potamogeton pectinatus that simultaneously occurs in freshwater lakes and coastal marine sites. Relative levels of gene flow were inferred in 12 lake and 14 Baltic Sea populations in northern Germany using nine highly polymorphic microsatellite markers developed for P. pectinatus. We found highly significant isolation‐by‐distance in both habitat types (P < 0.001). Genetic differentiation increased approximately 2.5‐times faster among freshwater populations compared with those from the Baltic Sea. As different levels of genetic drift or population history cannot explain these differences, higher population connectivity in the sea relative to freshwater populations is the most likely source of contrasting evolutionary divergence. These findings are consistent with the notion that freshwater angiosperms are more conducive to allopatric speciation than their life‐history counterparts in the sea, the relative species poor seagrasses. Surprisingly, population pairs from different habitat types revealed almost maximal genetic divergence expected for complete reproductive isolation, regardless of their respective geographical distance. Hence, the barrier to gene flow between lake and sea habitat types cannot be due to dispersal limitation. We may thus have identified a case of rapid incipient speciation in post‐glacial populations of a widespread aquatic plant.
Electrical and neurotransmitter activity of mature neurons derived from mouse embryonic stem cells by Sox‐1 lineage selection and directed differentiation
Authors: Lang R. J. , Haynes J. M. , Kelly J. , Johnson J. , Greenhalgh J. , O'Brien C. , Mulholland E. M. , Baker L. , Munsie M. , Pouton C. W.
Published: January 2005

Sx1TV2/16C is a mouse embryonic stem (ES) cell line in which one copy of the Sox1 gene, an early neuroectodermal marker, has been targeted with a neomycin (G418) selection cassette. A combination of directed differentiation with retinoic acid and G418 selection results in an enriched neural stem cell population that can be further differentiated into neurons. After 6–7 days post‐plating (D6–7PP) most neurons readily fired tetrodotoxin (TTX)‐sensitive action potentials due to the expression of TTX‐sensitive Na+ and tetraethylammonium (TEA)‐sensitive K+ channels. Neurons reached their maximal cell capacitance after D6–7PP; however, ion channel expression continued until at least D21PP. The percentage of cells receiving spontaneous synaptic currents (s.s.c.) increased with days in culture until 100% of cells received a synaptic input by D20PP. Spontaneous synaptic currents were reduced in amplitude and frequency by TTX, or upon exposure to a Ca2+‐free, 2.5 mm Mg2+ saline. S.s.c. of rapid decay time constants were preferentially blocked by the nonNMDA glutamatergic receptor antagonists CNQX or NBQX. Ca2+ levels within ES cell‐derived neurons increased in response to glutamate receptor agonists l‐glutamate, AMPA, N‐methyl‐d‐aspartate (NMDA) and kainic acid and to acetylcholine, ATP and dopamine. ES cell‐derived neurons also generated cationic and Cl–‐selective currents in response to NMDA and glycine or GABA, respectively. It was concluded that ES‐derived neurons fire action potentials, receive excitatory and inhibitory synaptic input and respond to various neurotransmitters in a manner akin to primary central neurons.
Mutant huntingtin affects the rate of transcription of striatum‐specific isoforms of phosphodiesterase 10A
Authors: Hu Haibei , McCaw Elizabeth A. , Hebb Andrea L. O. , Gomez Geraldine T. , Denovan‐Wright Eileen M.
Published: January 2005

Huntington's disease (HD) is caused by the inheritance of a copy of the gene encoding mutant huntingtin with an expanded CAG repeat. Phosphodiesterase 10A (PDE10A) mRNA decreases in transgenic HD mice expressing exon 1 of the human huntingtin gene (HD). The mouse PDE10A mRNA is expressed through alternative splicing and polyadenylation in a tissue‐specific manner and that transcription of striatal PDE10A mRNA is driven by two promoters. PDE10A2 is the predominant isoform of the gene is expressed in the striatum. Using in situ hybridization and quantitative RT‐PCR, we determined that decreased steady‐state levels of PDE10A2 mRNA were caused by an altered transcription initiation rate rather than by post‐transcriptional mRNA instability in HD mice. Transcription from three initiation sites located within a 50‐bp region in the PDE10A2‐specific promoter was differentially affected by the presence of the mutant huntingtin transgene. The mouse and human PDE10A2 promoters are highly conserved with respect to the relative position of cis‐regulatory elements. Several transcription factors that have been shown to interact with mutant huntingtin, including Sp1, neuron restrictive silencing factor, TATA‐binding protein and cAMP‐response element binding protein, are unlikely to be involved in mutant huntingtin‐induced PDE10A2 transcriptional dysregulation.
Distinct modulatory effects of sleep on the maintenance of hippocampal and medial prefrontal cortex LTP
Authors: Romcy‐Pereira Rodrigo , Pavlides Constantine
Published: January 2005

Both human and animal studies support the idea that memory consolidation of waking experiences occurs during sleep. In experimental models, rapid‐eye‐movement (REM) sleep has been shown to be necessary for cortical synaptic plasticity and for the acquisition of spatial and nonspatial memory. Because the hippocampus and medial prefrontal cortex (mPFC) play distinct and important roles in memory processing, we sought to determine the role of sleep in the maintenance of long‐term potentiation (LTP) in the dentate gyrus (DG) and mPFC of freely behaving rats. Animals were implanted with stimulating and recording electrodes, either in the medial perforant path and DG or CA1 and mPFC, for the recording of field potentials. Following baseline recordings, LTP was induced and the animals were assigned to three different groups: REM sleep‐deprived (REMD), total sleep‐deprived (TSD) and control which were allowed to sleep (SLEEP). The deprivation protocol lasted for 4 h and the recordings were made during the first hour and at 5, 24 and 48 h following LTP induction. Our results show that REMD impaired the maintenance of late‐phase (48‐h) LTP in the DG, whereas it enhanced it in the mPFC. Sleep, therefore, could have distinct effects on the consolidation of different forms of memory.
Blocking the R‐type (Cav2.3) Ca2+ channel enhanced morphine analgesia and reduced morphine tolerance
Authors: Yokoyama Kazuaki , Kurihara Takashi , Saegusa Hironao , Zong Shuqin , Makita Koshi , Tanabe Tsutomu
Published: January 2005

Morphine is the drug of choice to treat intractable pain, although prolonged administration often causes undesirable side‐effects including analgesic tolerance. It is speculated that voltage‐dependent Ca2+ channels (VDCCs) play a key role in morphine analgesia and tolerance. To examine the subtype specificity of VDCCs in these processes, we analysed mice lacking N‐type (Cav2.2) or R‐type (Cav2.3) VDCCs. Systemic morphine administration or exposure to warm water swim‐stress, known to induce endogenous opioid release, resulted in greater analgesia in Cav2.3−/− mice than in controls. Moreover, Cav2.3−/− mice showed resistance to morphine tolerance. In contrast, Cav2.2−/− mice showed similar levels of analgesia and tolerance to control mice. Intracerebroventricular (i.c.v.) but not intrathecal (i.t.) administration of morphine reproduced the result of systemic morphine in Cav2.3−/− mice. Furthermore, i.c.v. administration of an R‐type channel blocker potentiated morphine analgesia in wild‐type mice. Thus, the inhibition of R‐type Ca2+ current could lead to high‐efficiency opioid therapy without tolerance.
Cortical and medial amygdala are both involved in the formation of olfactory offspring memory in sheep
Authors: Keller Matthieu , Perrin Gaëlle , Meurisse Maryse , Ferreira Guillaume , Lévy Frédéric
Published: January 2005

Ewes form a selective olfactory memory for their lambs after 2 h of mother–young interaction following parturition. Once this recognition is established, ewes will subsequently reject any strange lamb approaching the udder (i.e. maternal selectivity). The present study tested the functional contribution of different amygdala nuclei to lamb olfactory memory formation. Using the anaesthetic lidocaine, cortical, medial or basolateral nuclei of the amygdala were transiently inactivated during lamb odour memory formation. Reversible inactivation of either cortical or medial amygdala during the first 8 h postpartum impaired lamb olfactory recognition, whereas inactivation of the basolateral nucleus or infusion of artificial cerebrospinal fluid did not. Control experiments indicate that inactivation of the cortical and medial nuclei of the amygdala specifically disrupt memory formation rather than olfactory perception or memory retrieval. These findings show that both nuclei of the amygdala are required for the formation of a lamb olfactory memory and suggest functional interaction between these two nuclei.
Gene expression profiles associated with survival of individual rat dentate cells after endogenous corticosteroid deprivation
Authors: Nair S. M. , Karst H. , Dumas T. , Phillips R. , Sapolsky R. M. , Rumpff‐van Essen L. , Maslam S. , Lucassen P. J. , Joëls M.
Published: January 2005

Removal of circulating corticosterone by adrenalectomy (ADX) leads to apoptosis after 3 days in a small population of rat dentate granule neurons, whereas most surrounding cells remain viable. Interestingly, a specific expression profile is triggered in surviving granule cells that may enhance their survival. Hippocampal slices prepared 1, 2 or 3 days after ADX or sham operation were stained ex vivo with Hoechst 33258, which serves to identify apoptotic neurons. After electrophysiological analysis, multiple gene expression in surviving individual granule cells was assessed by linear antisense RNA amplification and hybridization to slot blots containing various neuronal cDNAs. Hierarchical clustering and principal component analysis was performed on two physiological variables and 14 mRNA ratios from ADX cells from every time point. Our results indicate that surviving 3‐day ADX granule cells display lower membrane capacitance, lower relative N‐methyl‐d‐aspartate (NMDA) R1 mRNA expression and higher relative mineralocorticoid receptor (MR), α1A voltage‐gated Ca‐channel, Bcl‐2 and NMDA R2C mRNA expression. Some 1‐ and 2‐day ADX cells cluster with these 3‐day survivors; therefore, one or more components of their mRNA expression profile may represent predictive markers for apoptosis resistance. The functional relevance of two candidate genes was tested by in vivo local over‐expression in the same model system; of these, Bcl‐2 conferred partial protection when induced shortly before ADX. Therefore, removal of corticosteroids triggers a specific gene expression profile in surviving dentate granule cells; key components of this profile may be associated with their survival.
Large sample properties of spectral estimators for a class of stationary nonlinear processes
Authors: Chanda Kamal C.
Published: January 2005

Abstract.  We consider the standard spectral estimators based on a sample from a class of strictly stationary nonlinear processes which include, in particular, the bilinear and Volterra processes. It is shown that these estimators, under certain mild regularity conditions are both consistent and asymptotically normal.
Triclosan reduces microsomal prostaglandin E synthase‐1 expression in human gingival fibroblasts
Authors: Mustafa M. , Wondimu B. , Yucel‐Lindberg T. , Kats‐Hallström A. T. , Jonsson A. S. , Modéer T.
Published: January 2005

Objective: The effect of triclosan (2,4,4′‐trichloro‐2′‐hydroxydiphenyl ether) on the expression of cyclooxygenase‐2 (COX‐2) and microsomal prostaglandin E synthase‐1 (mPGES‐1) and on the translocation of the nuclear factor‐κB (NF‐κB) in relation to prostaglandin E2 (PGE2) production was investigated in human gingival fibroblasts challenged with tumor necrosis factor α (TNFα).

Methods: Fibroblasts were established from gingival biopsies obtained from six children. COX‐2 mRNA and protein expression was quantified using mRNA quantitation and enzyme immunometric assay kits. mPGES‐1 mRNA was analysed by RT‐PCR, mPGES‐1 protein and NF‐κB translocation by immunoblotting. PGE2 was determined by radioimmunoassay.

Results: The cytokine TNFα enhanced the expression of mRNA as well as the protein levels of both COX‐2 and mPGES‐1 and subsequently the production of PGE2 in gingival fibroblasts. Treatment of gingival fibroblasts with triclosan (1 μg/ml) significantly reduced the stimulatory effect of TNFα (10 ng/ml) on the expression of mPGES‐1 at both the mRNA and the protein level by an average of 21% and 43%, respectively, and subsequently the production of PGE2 (p<0.01). Triclosan did not, however, affect the translocation of NF‐κB or the expression of COX‐2 in TNFα‐stimulated cells.

Conclusion: The results show that triclosan reduces the augmented biosynthesis of PGE2 by inhibiting the mRNA and the protein expression of mPGES‐1 in gingival fibroblasts. This finding may partly explain the anti‐inflammatory effect of the agent previously reported in clinical studies.
Histologic, histomorphometric and immunohistologic changes of the gingival tissues immediately following mandibular osteodistraction
Authors: Kruse‐Lösler Birgit , Flören Christian , Stratmann Udo , Joos Ulrich , Meyer Ulrich
Published: January 2005

Objectives: Even though osteogenesis after osteodistraction has been investigated in numerous experimental studies, there is limited information focusing on the influence of well‐defined mechanical distraction forces on the associated gingival tissues.

Material and Methods: In a study including 48 rabbits, mandibular osteodistraction was performed in vertically osteotomized mandibular body, using defined distraction protocols with physiologic, moderate and hyperphysiologic forces. The soft tissues overlying the distraction gap were harvested finally for histologic, immunohistologic and histomorphometric investigations.

Results: The control group without distraction showed the typical architecture and thickness of normal gingiva. In groups with distracted mandibles, an accelerating atrophy of gingiva depending on the degree of mechanical loading was obvious, characterized by decreasing thickness of epithelial layer, loss of rete ridges and disorganization of the different cell layers with a high number of apoptotic cells. In lamina propria collagen fibres were reduced and elastic fibres increased. Histomorphometric analysis revealed significant correlation between degree of distraction and atrophy in overlying soft tissues.

Conclusion: This rabbit model of mandibular lengthening shows an accelerating atrophy in the covering soft tissues following hyperphysiologic distraction. The long‐term outcome of these distraction‐related soft‐tissue alterations remains unclear. The atrophic changes may likely be of temporary nature.
Tobacco smoking and subgingival dental calculus
Authors: Bergström Jan
Published: January 2005

Objective: A radiographic investigation into the relationship between tobacco smoking and subgingival dental calculus was conducted in an adult population, including 48 current smokers, 57 former smokers, and 125 non‐smokers.

Material and Methods: Assessment of subgingival calculus was based on a full set of radiographs. Mesial and distal root surfaces were assessed as to presence or absence of radiopaque deposits apical to the cemento‐enamel junction. The severity of subgingival calculus deposition, labeled subgingival calculus load, was estimated from both the total number and the proportion of proximal sites affected.

Results: The overall prevalence of individuals exhibiting at least one subgingival calculus positive site was 43%, ranging from 15% in age stratum 20–34 years to 72% in age stratum 50–69 years. The prevalence among current smokers, former smokers, and non‐smokers was 71%, 53%, and 28%, respectively. The differences between smoking groups were statistically significant (p<0.001). The mean subgingival calculus load of current smokers, former smokers, and non‐smokers was 3.4, 1.2, and 0.6 affected sites per person, respectively, or expressed as mean proportions, 6.2%, 2.4%, and 1.1%, respectively. The association between smoking and subgingival calculus load was statistically significant (p<0.001). The subgingival calculus load increased with increasing smoking exposure, suggesting a dose–response relationship.

Conclusion: The present observations in dentally aware adults indicate a strong and independent impact of tobacco smoking on subgingival calculus deposition.