bluuebunny/crossref_metadata_2025_split huggingface dataset:
Primary aldosteronism: renaissance of a syndrome
Authors: Young William F. 
Published: February 2007

SummaryGreat strides have been made in our understanding of the pathophysiology of primary aldosteronism syndrome since Conn's description of the clinical presentation of a patient with an aldosterone‐producing adenoma (APA) more than 50 years ago. It is now recognized that the APA is just one of the seven subtypes of primary aldosteronism. APA and bilateral idiopathic hyperaldosteronism (IHA) are the most common subtypes of primary aldosteronism. Although most clinicians had thought primary aldosteronism to be a rare form of hypertension for more than three decades, it is now recognized to be the most common form of secondary hypertension. Using the plasma aldosterone to plasma renin activity ratio as a case‐finding test, followed by aldosterone suppression confirmatory testing, has resulted in much higher prevalence estimates of 5–13% of all patients with hypertension. In addition, there has been a new recognition of the aldosterone‐specific cardiovascular morbidity and mortality associated with aldosterone excess. Although thought to be daunting and complex in the past, the diagnostic approach to primary aldosteronism is straightforward and can be considered in three phases: case‐finding tests, confirmatory tests and subtype evaluation tests. Patients with hypertension and hypokalaemia (regardless of presumed cause), treatment‐resistant hypertension (three antihypertensive drugs and poor control), severe hypertension (≥ 160 mmHg systolic or ≥ 100 mmHg diastolic), hypertension and an incidental adrenal mass, onset of hypertension at a young age or patients being evaluated for other forms of secondary hypertension should undergo screening for primary aldosteronism. In patients with suspected primary aldosteronism, screening can be accomplished by measuring a morning (preferably between 0800 and 1000 h) ambulatory paired random plasma aldosterone concentration (PAC) and plasma renin activity (PRA). An increased PAC:PRA ratio is not diagnostic by itself, and primary aldosteronism must be confirmed by demonstrating inappropriate aldosterone secretion. Aldosterone suppression testing can be performed with orally administered sodium chloride and measurement of urinary aldosterone or with intravenous sodium chloride loading and measurement of PAC. Unilateral adrenalectomy in patients with APA or unilateral adrenal hyperplasia results in normalization of hypokalaemia in all these patients; hypertension is improved in all and is cured in approximately 30–60% of them. In bilateral adrenal forms of primary aldosteronism, unilateral or bilateral adrenalectomy seldom corrects the hypertension and they should be treated medically with a mineralocorticoid receptor antagonist.
Circulating obestatin levels in normal subjects and in patients with impaired glucose regulation and type 2 diabetes mellitus
Authors: Qi Xiaoya , Li Ling , Yang Gangyi , Liu Jianlei , Li Ke , Tang Yi , Liou Hua , Boden Guenther 
Published: February 2007

SummaryBackground  Obestatin is a novel hormone that is encoded by the Ghrelin gene and produced in the gut. Ghrelin is profoundly orexogenic and adipogenic, increasing food intake and body weight. This new ghrelin‐associated peptide behaves as a physiological opponent of ghrelin in rodent animals, but its pathophysiological role in humans remains unknownObjective  In this study we investigate whether plasma obestatin level is different in patients with impaired glucose regulation (IGR) and type 2 diabetes mellitus (T2DM).Patients and measurements  Forty‐seven patients with T2DΜ, 30 subjects with IGR, and 38 sex‐ and age‐matched normal controls participated in the study. Plasma obestatin levels were measured with a radioimmunoassay. The relationship between plasma obestatin levels and anthropometric and metabolic parameters was also analysed.Results  Plasma obestatin levels were lower in patients with T2DM and IGR than in controls (37·5 ± 9·2 ng/l and 39·2 ± 9·7 ng/l vs. 43·8 ± 8·0 ng/l, P = 0·002 and P = 0·039, respectively). Decreasing concentrations of obestatin were independently and significantly associated with IGR and T2DM. Multiple logistic regression analysis revealed obestatin to be independently associated with IGR and T2DM. In a multiple linear regression analysis, only waist‐to‐hip ratio and homeostasis model assessment of insulin resistance (HOMA‐IR) were independently associated with plasma obestatin level.Conclusion  Our results suggest that obestatin may play a role in appetite regulation in patients with IGR and T2DM.
N‐terminal pro‐B‐type natriuretic peptide in patients with growth hormone disturbances
Authors: Andreassen Mikkel , Faber Jens , Vestergaard Henrik , Kistorp Caroline , Kristensen Lars Østergaard 
Published: February 2007

SummaryBackground  Acromegaly is associated with hypertrophic cardiomyopathy, hypertension and subsequent congestive heart failure. Impairment of cardiac function has also been associated with growth hormone deficiency (GHD). B‐type natriuretic peptides (BNPs) have emerged as strong diagnostic and prognostic risk markers. They are cardioprotective hormones that compensate heart disease by promoting natriuresis and modulation of cardiac hypertrophy in response to volume expansion and ventricular wall stretch.Objective  To investigate N‐terminal pro‐BNP (NT‐proBNP) in patients with GH disturbances before and after treatment, and in healthy gender‐ and age‐matched controls.Subjects and methods  Ten acromegalic patients (age 48 ± 12 years) and 10 patients with GHD (age 41 ± 14 years) were studied. None had symptoms or signs of cardiovascular disease except for hypertension. Serum NT‐proBNP was measured before and 3, 6, 12 and 24 months after treatment.Results  Baseline NT‐proBNP was lower in acromegalic patients [median (interquartile range) 24·3 (17·8–33·0) pg/ml] than in 20 healthy matched controls [57·9 (35·4–92·2) pg/ml; P < 0·001]. NT‐proBNP increased during treatment (P = 0·002), concomitant with a decrease in IGF‐I (P < 0·001). After 3 months of treatment NT‐proBNP peaked, with a fourfold increase to 96·4 (57·8–113·2) pg/ml. NT‐proBNP did not differ in patients with GHD compared with controls (P = 0·19), and did not change during treatment (P = 0·39).Conclusion  Untreated patients with acromegaly had low NT‐proBNP levels that increased fourfold after treatment. This is in contrast to other conditions with cardiac hypertrophy. Further studies are required to determine the significance of this novel finding in relation to acromegalic cardiac disease.
The influence of the route of oestrogen administration on serum levels of cortisol‐binding globulin and total cortisol
Authors: Qureshi Ayesha C. , Bahri Aman , Breen Louise A. , Barnes Sophie C. , Powrie Jake K. , Thomas Stephen M. , Carroll Paul V. 
Published: February 2007

SummaryObjectives  Oral oestrogen preparations increase total cortisol concentration by increasing circulating cortisol‐binding globulin (CBG) levels. Transdermal oestrogen treatments are being used increasingly in clinical practice. These topical preparations may have less of an effect on CBG and hence on total serum cortisol levels by reducing hepatic oestrogen exposure. The purpose of this study was to compare the effects of oral and topical oestrogen treatments on CBG, total serum cortisol and salivary cortisol levels.Design and Patients  This was a single‐centre, cross‐sectional study of 37 women aged 33 ± 6 years (mean ± SD). Fourteen women were using oral oestrogen therapy, eight were using transdermal therapy and 15 were oestrogen‐naïve control subjects.Measurements  Following a screening visit, the subjects attended the endocrine investigation unit following an overnight fast. Blood and salivary samples were taken from 0830 to 0930 h between days 10 and 18 of the menstrual cycle (where appropriate).Results  Total serum cortisol concentrations were 67% higher in those receiving oral oestrogen when compared to control subjects (660·9 ± 89·9 vs. 395·4 ± 53·2 nmol/l, P < 0·001). Values in those receiving transdermal oestrogen (334·7 ± 72·0 nmol/l) were no different from the control group. CBG levels were higher in those on oral oestrogen therapy (110·9 ± 19·6 mg/l, P < 0·001) when compared with either those on transdermal oestrogen (51·0 ± 5·4 mg/l) or the control population (49·0 ± 11·8 mg/l). Similar salivary cortisol concentrations were recorded in the three groups (controls 13·8 ± 2·6 nmol/l, oral oestrogen 15·5 ± 2·6 nmol/l, transdermal oestrogen 15·7 ± 3·9 nmol/l).Conclusions  Oral oestrogen‐containing preparations increase total cortisol levels by increasing circulating CBG concentration. These effects were not seen in patients using transdermal oestrogen replacement. Although further studies are indicated, it is probably unnecessary to routinely discontinue transdermal oestrogen replacement when performing an assessment of the hypothalamic–pituitary–adrenal (HPA) axis or evaluating adequacy of hydrocortisone replacement.
Ontogeny of foetal exposure to maternal cortisol using midtrimester amniotic fluid as a biomarker
Authors: Sarkar P. , Bergman K. , Fisk N. M. , O’Connor T. G. , Glover V. 
Published: February 2007

SummaryObjective  There is increasing evidence that antenatal stress has long‐lasting effects on child development, but there is less accord on the mechanisms and the gestational window of susceptibility. One possible mechanism is by foetal exposure to maternal cortisol. To explore this, we investigated the relationship between cortisol in maternal plasma and amniotic fluid, and any moderating influence of gestational age.Patients and measurements  Two hundred and sixty‐seven women awaiting amniocentesis for karyotyping were studied. Samples were collected between 0900 and 1730 h. Gestational age was determined to the nearest day by ultrasound biometry and time of collection noted to the nearest 15 min. Total cortisol was measured by radioimmunoassay in paired amniotic fluid and maternal blood samples (n = 267) [gestation range 15–37 weeks, median 17 weeks (119 days)].Results  Both maternal and amniotic fluid cortisol levels increased with gestation (r = 0·25, P < 0·001; r = 0·33 P < 0·001, respectively). Amniotic fluid cortisol was positively correlated with time of collection (r = 0·22, P < 0·001) and negatively with maternal age (r =−0·24, P < 0·001). There was a positive correlation between amniotic fluid cortisol with maternal plasma levels (r = 0·32, P < 0·001), which persisted after multivariate analysis controlling for gestation, time of collection and maternal age. The association appeared to be dependent on gestational age, being nonsignificant at 15–16 weeks’ gestation and increasing in strength thereafter.Conclusion  This study shows a positive correlation between maternal and amniotic fluid cortisol levels, which becomes robust from 17 to 18 weeks onwards. The results provide support for the hypothesis that alterations in maternal cortisol may be reflected in amniotic fluid levels from this gestation.
Genetic diversity and historical population structure of Schizopygopsis pylzovi (Teleostei: Cyprinidae) in the Qinghai–Tibetan Plateau
Authors: QI DELIN , GUO SONGCHANG , ZHAO XINQUAN , YANG JIE , TANG WENJIA 
Published: February 2007

Summary1. Complete sequences of 1140 base pair of the cytochrome b gene from 133 specimens were obtained from nine localities including the inflow drainage system, isolated lakes and outflow drainage system in Qinghai–Tibetan Plateau to assess genetic diversity and to infer population histories of the freshwater fish Schizopygopsis pylzovi.2. Nucleotide diversities (π) were moderate (0.0024–0.0045) in populations from the outflow drainage system and Tuosuo Lake, but low (0.0018–0.0021) in populations from Qiadam Basin. It is probable that the low intra‐population variability is related with the paleoenvironmental fluctuation in Qiadam Basin, suggesting that the populations from Qiadam Basin have experienced severe bottleneck events in history.3. Phylogenetic tree topologies indicate that the individuals from different populations did not form reciprocal monophyly, but the populations from the adjacent drainages cluster geographically. Most population pairwise FST tests were significant, with non‐significant pairwise tests between Tuosu Lake and Tuosuo Lake in the north‐west of the Qinghai–Tibetan Plateau. Analysis of molecular variance (amova) indicates that the significant genetic variation was explained at the levels of catchments within and among, not among specific boundaries or inflow and outflow drainage systems.4. The nested clade phylogeographical analysis indicates that historical processes are very important in the observed geographical structuring of S. pylzovi, and the contemporary population structure and differentiation of S. pylzovi may be consistent with the historical tectonic events occurred in the course of uplifts of the Qinghai–Tibetan Plateau. Fluctuations of the ecogeographical environment and major hydrographic formation might have promoted contiguous range expansion of freshwater fish populations, whereas the geological barriers among drainages have resulted in the fragmentation of population and restricted the gene flow among populations.5. The significantly large negative Fs‐value (−24.91, P < 0.01) of Fu's Fs‐test and the unimodal mismatch distribution indicate that the species S. pylzovi underwent a sudden population expansion after the historical tectonic event of the Gonghe Movement.6. The results of this study indicate that each population from the Qinghai–Tibetan Plateau should be managed and conserved separately and that efforts should be directed towards preserving the genetic integrity of each group.
The effect of seasonal variation in selective feeding by zebra mussels (Dreissena polymorpha) on phytoplankton community composition
Authors: NADDAFI RAHMAT , PETTERSSON KURT , EKLÖV PETER 
Published: February 2007

Summary1. To investigate the impact of zebra mussels (Dreissena polymorpha) on phytoplankton community composition, temporal variability in selective feeding by the mussels was determined from April to November 2005 in a natural lake using Delayed Fluorescence (DF) excitation spectroscopy.2. Selective grazing by zebra mussels varied in relation to seasonal phytoplankton dynamics; mussels showed a consistent preference for cryptophytes and avoidance of chlorophytes and cyanobacteria. Diatoms, chrysophytes and dinoflagellates responded differentially to zebra mussel grazing depending on their size. Analysis of excreted products of the zebra mussels revealed that in addition to chlorophytes and cyanobacteria, phytoplankton >50 μm and very small phytoplankton (≤7 μm) were largely expelled in pseudofaeces.3. The zebra mussel is a selective filter‐feeder that alters its feeding behaviour in relation to phytoplankton composition to capture and ingest high quality phytoplankton, especially when phytoplankton occur in preferred size ranges. Flexibility of zebra mussel feeding behaviour and variation in susceptibility among phytoplankton groups to mussel ingestion indicate that invading zebra mussels could alter phytoplankton community composition of lakes and have important ecosystem consequences.
Characterization of two globin genes from the malaria mosquito Anopheles gambiae: Divergent origin of nematoceran haemoglobins
Authors: Burmester Thorsten , Klawitter Sabine , Hankeln Thomas 
Published: February 2007

AbstractThe chironomid midges are the only insects that harbour true haemoglobin in their haemolymph. Here we report the identification of haemoglobin genes in two other nematoceran species. Two paralogous haemoglobin genes (glob1 and glob2) from the malaria mosquito Anopheles gambiae were cloned and sequenced. Furthermore, we identified two orthologous haemoglobin genes in the yellow fever mosquito Aedes aegypti. All four haemoglobins were predicted to be intracellular proteins, with the amino acids required for heme‐ and oxygen‐binding being conserved. In situ‐hybridization studies showed that glob1 and glob2 expression in An. gambiae is mainly associated with the tracheal system. This pattern resembles that of other insect intracellular globins. We also observed expression of glob2 in visceral muscles. Phylogenetic analyses showed that the globins of the mosquitoes and the Chironomidae are not orthologous. The chironomid haemoglobins share a recent common origin with the brachyceran glob1 proteins. The mosquito glob1 and glob2 proteins, which separated by gene duplication around 170 million years ago, form a distinct clade of more ancient evolutionary origin within the insects. The glob1 genes have introns in the ancestral globin positions B12.2 and G7.0. An additional intron was observed in Ae. aegypti glob1 helix position E18.0, providing evidence for a recent intron gain event. Both mosquito glob2 genes have lost the B12.2 intron. This pattern must be interpreted in terms of dynamic intron gain and loss events in the globin gene lineage.
GP35 ANOAL, an abundant acidic glycoprotein of female Anopheles albimanus saliva
Authors: Cázares‐Raga F. E. , González‐Lázaro M. , Montero‐Solís C. , González‐Cerón L. , Zamudio F. , Martínez‐Barnetche J. , Torres‐Monzón J. A. , Ovilla‐Muñoz M. , Aguilar‐Fuentes J. , Rodríguez M. H. , De La Cruz Hernández‐Hernández F. 
Published: February 2007

AbstractSalivary glands of female mosquitoes produce proteins, not completely described yet, that participate in carbohydrate and blood feeding. Here, we report an acidic glycoprotein of 35 kDa (GP35 ANOAL) secreted in the saliva of the malaria vector mosquito Anopheles albimanus. GP35 ANOAL is produced exclusively in the distal lateral lobes of adult female salivary glands, it has a pI of 4.45 and is negatively stained by regular silver stain. An 888 bp cDNA clone encoding a predicted product of 240 amino acids has a signal peptide, potential post‐translational modification sites, and a disintegrin signature RGD. The GP35 ANOAL sequence depicts high similarities with the 30 kDa saliva allergen of Aedes aegypti, 30 kDa allergen‐like hypothetical proteins, and GE‐rich proteins present in several Anopheles species, as well as in Ae. albopictus and Culex pipiens quinquefasciatus. The function of this protein family is still unknown.
Short‐hairpin RNA expressed from polymerase III promoters mediates RNA interference in mosquito cells
Authors: Konet D. S. , Anderson J. , Piper J. , Akkina R. , Suchman E. , Carlson J. 
Published: February 2007

AbstractPutative U6snRNA polymerase III (PolIII) promoters were cloned from the Anopheles gambiae and Aedes aegypti genomes. The PolIII promoters were tested for their ability to express short‐hairpin RNA (shRNA) targeted to firefly luciferase and to mediate RNA interference (RNAi) knockdown of a co‐transfected luciferase reporter gene vector in AG‐55 Anopheles gambiae and ATC‐10 Aedes aegypti cells. Promoters capable of silencing expression of the co‐transfected luciferase plasmid by up to 95% in AG‐55 cells and up to 75% in ATC‐10 cells were identified. RNase protection experiments allowed detection of the 19 nt luciferase short‐interfering RNA (siRNA) in transfected cells. These findings indicate that mosquito U6snRNA gene promoters can be used for production of shRNA to induce the RNAi response in mosquito cells.
cDNA cloning of heat shock proteins and their expression in the two phases of the migratory locust
Authors: Wang H.‐S. , Wang X.‐H. , Zhou C.‐S. , Huang L.‐H. , Zhang S.‐F. , Guo W. , Kang L. 
Published: February 2007

AbstractThe high population density of insects is often a stress factor. Insects synthesize heat shock proteins (Hsps) in response to the impacts of stress through molecular chaperone activity. Locust solitary and gregarious phases occur at low and high population density, respectively. In this study, we compare the expression profiles of the Hsp genes in the two phases of the migratory locust in an attempt to examine the role of Hsps in adaptation to high density populations. The full length cDNAs of Hsp20.5, 20.6, 20.7, 40, 70 and Hsp90 of the migratory locust were cloned and sequenced. The expressional differentiation of the six Hsps in mRNA levels between solitary and gregarious locusts was observed. Results from real‐time PCR indicate that the six Hsps are expressed throughout all developmental stages except in the early stage embryo. The expression levels of the six Hsps were significantly upregulated in gregarious locusts. The expressional variations among certain organs, such as the head, thorax and leg of fifth instar nymphs in gregarious locusts were also higher than those in solitary ones. These observations suggest that population density may be an important factor in determining Hsp expression in the locust.
The transformer gene in Bactrocera oleae: the genetic switch that determines its sex fate
Authors: Lagos D. , Koukidou M. , Savakis C. , Komitopoulou K. 
Published: February 2007

Abstract Transformer (tra) is the second gene of a regulatory cascade based on RNA splicing that determines sex in Drosophila melanogaster. Splicing of tra transcripts is regulated by the master gene Sex lethal and tra itself regulates splicing of the transcriptional regulator doublesex (dsx). We present the isolation and characterization of Botra, the olive fruit fly Bactrocera oleae orthologue to the Drosophila gene transformer. As in Drosophila, Botra transcripts are spliced in a sex‐specific manner so that only females encode a functional polypeptide of 422 amino acids, whereas males encode presumably nonfunctional peptide(s). The identification of multiple TRA/TRA‐2 binding sites within the Botra male‐specific exons, suggests an autoregulation mechanism of tra, through TRA/TRA2 activities. The fundamental role of the TRA protein in sex determination of Bactrocera was investigated by RNA interference, where the introduction of Botra dsRNA into embryos resulted in complete transformation of XX flies into fertile males.
Molecular cloning of the precursor polypeptide of mastoparan B and its putative processing enzyme, dipeptidyl peptidase IV, from the black‐bellied hornet, Vespa basalis
Authors: Lee V. S. Y. , Tu W.‐C. , Jinn T.‐R. , Peng C.‐C. , Lin L.‐J. , Tzen J. T. C. 
Published: February 2007

AbstractMastoparan B, a cationic toxin, is the major peptide component in the venom of Vespa basalis. Molecular cloning of its cDNA fragment revealed that this toxin was initially synthesized as a precursor polypeptide, containing an N‐terminal signal sequence, a prosequence, the mature toxin, and an appendix glycine at C‐terminus. Sequence alignment between precursors of mastoparan B and melittin from honeybee venom showed a significant conservation in prosequence. Alternate positions existing in both prosequences were either proline or alanine known as the potential cleaving sites for dipeptidyl peptidase IV. Subsequently, a putative dipeptidyl peptidase IV cDNA fragment was cloned from Vespa basalis venom gland. The prosequence may possibly be removed via sequential liberation of dipeptides during the processing of mastoparan B.
Characterization of core promoter elements for ecdysone receptor isoforms of the silkworm, Bombyx mori
Authors: Shirai H. , Kamimura M. , Fujiwara H. 
Published: February 2007

AbstractTwo ecdysone receptor (EcR) isoforms, EcR‐A and EcR‐B1, are expressed in a tissue‐ and stage‐specific manner, although the details of their transcription mechanisms are unknown. We determined the transcription start sites of EcR‐A and EcR‐B1 isoforms of Bombyx mori and found that both core promoter regions consist of initiator (Inr) and downstream promoter elements (DPE) but not TATA boxes. Promoter truncation analysis performed using the luciferase reporter assays and BmN cells showed that, in both isoforms, the regions −296 to −74 for BmEcR‐B1, −104 to −61 for BmEcR‐A and downstream regions of +1 are essential for basal transcriptional activity. Mutation experiments revealed that both DPE and its 5′‐flanking CGCGCG sequence are crucial but DPE of BmEcR‐B1 is not important for BmEcR‐A transcription. These results indicate that the basal promoter activities differ between the two BmEcR isoforms.