bluuebunny/crossref_metadata_2025 huggingface dataset:
New directions in single-molecule imaging and analysis
Authors: Moerner W. E.
Published: July 2007

Optical imaging and analysis of single molecules continue to unfold as powerful ways to study the individual behavior of biological systems, unobscured by ensemble averaging. Current expansion of interest in this field is great, as evidenced by new meetings, journal special issues, and the large number of new investigators. Selected recent advances in biomolecular analysis are described, and two new research directions are summarized: superresolution imaging using single-molecule fluorescence and trapping of single molecules in solution by direct suppression of Brownian motion.
Assays of vacuole fusion resolve the stages of docking, lipid mixing, and content mixing
Authors: Jun Youngsoo , Wickner William
Published: July 2007

Membrane fusion entails organelle docking and subsequent mixing of membrane bilayers and luminal compartments. We now present an
in vitro
assay of fusion, using yeast vacuoles bearing domains of either Fos or Jun fused to complementary halves of β-lactamase. Upon fusion, these proteins associate to yield β-lactamase activity. This assay complements the standard fusion assay (activation of pro-Pho8p in protease-deficient vacuoles by proteases from
pho8
Δ vacuoles). Both the β-lactamase and pro-Pho8p activation assays of fusion show the same long kinetic delay between SNARE pairing and luminal compartment mixing. Lipid-mixing occurs rapidly after SNARE pairing but well before aqueous compartment mixing. These results support a model in which SNARE pairing leads to rapid hemifusion, followed by slow further lipid rearrangement and aqueous compartment mixing.
Cellular senescence is an important mechanism of tumor regression upon c-Myc inactivation
Authors: Wu Chi-Hwa , van Riggelen Jan , Yetil Alper , Fan Alice C. , Bachireddy Pavan , Felsher Dean W.
Published: July 2007

Oncogene-induced senescence is an important mechanism by which normal cells are restrained from malignant transformation. Here we report that the suppression of the c-Myc (MYC) oncogene induces cellular senescence in diverse tumor types including lymphoma, osteosarcoma, and hepatocellular carcinoma. MYC inactivation was associated with prototypical markers of senescence, including acidic β-gal staining, induction of p16INK4a, and p15INK4b expression. Moreover, MYC inactivation induced global changes in chromatin structure associated with the marked reduction of histone H4 acetylation and increased histone H3 K9 methylation. Osteosarcomas engineered to be deficient in p16INK4a or Rb exhibited impaired senescence and failed to exhibit sustained tumor regression upon MYC inactivation. Similarly, only after lymphomas were repaired for p53 expression did MYC inactivation induce robust senescence and sustained tumor regression. The pharmacologic inhibition of signaling pathways implicated in oncogene-induced senescence including ATM/ATR and MAPK did not prevent senescence associated with MYC inactivation. Our results suggest that cellular senescence programs remain latently functional, even in established tumors, and can become reactivated, serving as a critical mechanism of oncogene addiction associated with MYC inactivation.
Existence of transient functional double-stranded DNA intermediates during recombinant AAV transduction
Authors: Wang Jinhui , Xie Jing , Lu Hui , Chen Lingxia , Hauck Bernd , Samulski Richard Jude , Xiao Weidong
Published: July 2007

Previous studies have documented that 0.1≈1% of input recombinant adeno-associated virus (rAAV) vectors could be stabilized and lead to transgene expression. To characterize the steps involving massive AAV DNA loss, we designed an“AAV footprinting” strategy that can track newly formed AAV dsDNA genomes. This strategy is based on an ROSA26R mouse model or cell line that carries a
lacZ
gene flanked by two loxP sites. When it is transduced by a rAAV vector carrying the Cre recombinase, the
lacZ
gene can be activated and remain active even when rAAV genomes are later lost. By using this sensitive AAV footprinting technique, we confirmed the existence of transient AAV dsDNA that went undetected by conventional DNA methods. Although these dsDNA intermediates could be efficiently formed in almost every cell and were competent for mRNA transcription and protein synthesis
in vivo
, they got lost continuously. Only a small fraction was eventually stabilized for sustained gene expression. Although both rAAV2 and rAAV8 can potentially have similar levels of dsDNA formation, AAV8 dsDNA was formed much faster than that of AAV2, which explains why rAAV8 is more efficient than rAAV2 in transducing the liver. Collectively, our studies suggested that rather than receptor binding, viral entry, and ssDNA to dsDNA conversion, the instability of newly formed AAV dsDNA was the primary contributing factor for the low rAAV transduction efficacy. The uncoating step significantly influenced the stability of AAV transient dsDNA. The identification of transient AAV dsDNA provided a new pathway for improving rAAV transduction.
Long-term maintenance of species-specific bacterial microbiota in the basal metazoan
Hydra
Authors: Fraune Sebastian , Bosch Thomas C. G.
Published: July 2007

Epithelia in animals are colonized by complex communities of microbes. Although a topic of long-standing interest, understanding the evolution of the microbial communities and their role in triggering innate immune responses has resisted analysis. Cnidaria are among the simplest animals at the tissue grade of organization. To obtain a better understanding of the microbiota associated with phylogenetically ancient epithelia, we have identified the epibiotic and endosymbiotic bacteria of two species of the cnidarian
Hydra
on the basis of rRNA comparisons. We analyzed individuals of
Hydra oligactis
and
Hydra vulgaris
from both laboratory cultures and the wild. We discovered that individuals from both species differ greatly in their bacterial microbiota. Although
H. vulgaris
polyps have a quite diverse microbiota,
H. oligactis
appears to be associated with only a limited number of microbes; some of them were found, unexpectedly, to be endosymbionts. Surprisingly, the microfauna showed similar characteristics in individuals of cultures maintained in the laboratory for >30 years and polyps directly isolated from the wild. The significant differences in the microbial communities between the two species and the maintenance of specific microbial communities over long periods of time strongly indicate distinct selective pressures imposed on and within the epithelium. Our analysis suggests that the
Hydra
epithelium actively selects and shapes its microbial community.
Two-dimensional spectroscopy at infrared and optical frequencies
Authors: Hochstrasser Robin M.
Published: July 2007

This Perspective on multidimensional spectroscopy in the optical and infrared spectral regions focuses on the principles and the scientific and technical challenges facing these new fields. The methods hold great promise for advances in the visualization of time-dependent structural changes in complex systems ranging from liquids to biological assemblies, new materials, and fundamental physical processes. The papers in this special feature on multidimensional spectroscopy in chemistry, physics, and biology are typical of many recent advances.
Unsupervised learning of vowel categories from infant-directed speech
Authors: Vallabha Gautam K. , McClelland James L. , Pons Ferran , Werker Janet F. , Amano Shigeaki
Published: July 2007

Infants rapidly learn the sound categories of their native language, even though they do not receive explicit or focused training. Recent research suggests that this learning is due to infants' sensitivity to the distribution of speech sounds and that infant-directed speech contains the distributional information needed to form native-language vowel categories. An algorithm, based on Expectation–Maximization, is presented here for learning the categories from a sequence of vowel tokens without (
i
) receiving any category information with each vowel token, (
ii
) knowing in advance the number of categories to learn, or (
iii
) having access to the entire data ensemble. When exposed to vowel tokens drawn from either English or Japanese infant-directed speech, the algorithm successfully discovered the language-specific vowel categories (/
i
, i, ε, e/ for English, /i, iː, e, eː/ for Japanese). A nonparametric version of the algorithm, closely related to neural network models based on topographic representation and competitive Hebbian learning, also was able to discover the vowel categories, albeit somewhat less reliably. These results reinforce the proposal that native-language speech categories are acquired through distributional learning and that such learning may be instantiated in a biologically plausible manner.
LIM-homeodomain proteins Lhx1 and Lhx5, and their cofactor Ldb1, control Purkinje cell differentiation in the developing cerebellum
Authors: Zhao Yangu , Kwan Kin-Ming , Mailloux Christina M. , Lee Woon-Kyu , Grinberg Alexander , Wurst Wolfgang , Behringer Richard R. , Westphal Heiner
Published: July 2007

Purkinje cells are one of the major types of neurons that form the neural circuitry in the cerebellum essential for fine control of movement and posture. During development, Purkinje cells also are critically involved in the regulation of proliferation of progenitors of granule cells, the other major type of neurons in the cerebellum. The process that controls differentiation of Purkinje cells from their early precursors is poorly understood. Here we report that two closely related LIM-homeobox genes,
Lhx1
and
Lhx5
, were expressed in the developing Purkinje cells soon after they exited the cell cycle and migrated out of the cerebellar ventricular zone. Double-mutant mice lacking function of both
Lhx1
and
Lhx5
showed a severe reduction in the number of Purkinje cells. In addition, targeted inactivation of
Ldb1
, which encodes a cofactor for all LIM-homeodomain proteins, resulted in a similar phenotype. Our studies thus provide evidence that these transcription regulators are essential for controlling Purkinje cell differentiation in the developing mammalian cerebellum.
Digital PCR for the molecular detection of fetal chromosomal aneuploidy
Authors: Lo Y. M. Dennis , Lun Fiona M. F. , Chan K. C. Allen , Tsui Nancy B. Y. , Chong Ka C. , Lau Tze K. , Leung Tak Y. , Zee Benny C. Y. , Cantor Charles R. , Chiu Rossa W. K.
Published: July 2007

Trisomy 21 is the most common reason that women opt for prenatal diagnosis. Conventional prenatal diagnostic methods involve the sampling of fetal materials by invasive procedures such as amniocentesis. Screening by ultrasonography and biochemical markers have been used to risk-stratify pregnant women before definitive invasive diagnostic procedures. However, these screening methods generally target epiphenomena, such as nuchal translucency, associated with trisomy 21. It would be ideal if noninvasive genetic methods were available for the direct detection of the core pathology of trisomy 21. Here we outline an approach using digital PCR for the noninvasive detection of fetal trisomy 21 by analysis of fetal nucleic acids in maternal plasma. First, we demonstrate the use of digital PCR to determine the allelic imbalance of a SNP on
PLAC4
mRNA, a placenta-expressed transcript on chromosome 21, in the maternal plasma of women bearing trisomy 21 fetuses. We named this the digital RNA SNP strategy. Second, we developed a nonpolymorphism-based method for the noninvasive prenatal detection of trisomy 21. We named this the digital relative chromosome dosage (RCD) method. Digital RCD involves the direct assessment of whether the total copy number of chromosome 21 in a sample containing fetal DNA is overrepresented with respect to a reference chromosome. Even without elaborate instrumentation, digital RCD allows the detection of trisomy 21 in samples containing 25% fetal DNA. We applied the sequential probability ratio test to interpret the digital PCR data. Computer simulation and empirical validation confirmed the high accuracy of the disease classification algorithm.
Genes overexpressed in different human solid cancers exhibit different tissue-specific expression profiles
Authors: Axelsen Jacob Bock , Lotem Joseph , Sachs Leo , Domany Eytan
Published: July 2007

We have analyzed gene expression in different normal human tissues and different types of solid cancers derived from these tissues. The cancers analyzed include brain (astrocytoma and glioblastoma), breast, colon, endometrium, kidney, liver, lung, ovary, prostate, skin, and thyroid cancers. Comparing gene expression in each normal tissue to 12 other normal tissues, we identified 4,917 tissue-selective genes that were selectively expressed in different normal tissues. We also identified 2,929 genes that are overexpressed at least 4-fold in the cancers compared with the normal tissue from which these cancers were derived. The overlap between these two gene groups identified 1,340 tissue-selective genes that are overexpressed in cancers. Different types of cancers, including different brain cancers arising from the same lineage, showed differences in the tissue-selective genes they overexpressed. Melanomas overexpressed the highest number of brain-selective genes and this may contribute to melanoma metastasis to the brain. Of all of the genes with tissue-selective expression, those selectively expressed in testis showed the highest frequency of genes that are overexpressed in at least two types of cancer. However, colon and prostate cancers did not overexpress any testis-selective gene. Nearly all of the genes with tissue-selective expression that are overexpressed in cancers showed selective expression in tissues different from the cancers' tissue of origin. Cancers aberrantly expressing such genes may acquire phenotypic alterations that contribute to cancer cell viability, growth, and metastasis.
Voluntary exercise together with oral caffeine markedly stimulates UVB light-induced apoptosis and decreases tissue fat in SKH-1 mice
Authors: Lu Yao-Ping , Nolan Bonnie , Lou You-Rong , Peng Qing-Yun , Wagner George C. , Conney Allan H.
Published: July 2007

Treatment of SKH-1 mice orally with caffeine (0.1 mg/ml in the drinking water), voluntary running wheel exercise, or a combination of caffeine and exercise for 2 weeks (i) decreased the weight of the parametrial fat pads by 35, 62, and 77%, respectively; (ii) decreased the thickness of the dermal fat layer by 38, 42, and 68%, respectively; (iii) stimulated the formation of UVB-induced apoptotic sunburn cells in the epidermis by 96, 120, and 376%, respectively; and (iv) stimulated the formation of UVB-induced caspase 3 (active form)-positive cells in the epidermis by 92, 120, and 389%, respectively (average of two experiments). Oral administration of caffeine (0.4 mg/ml in the drinking water) in combination with voluntary exercise was less effective than administration of the low dose of caffeine in combination with exercise in stimulating UVB-induced apoptosis. Although orally administrated caffeine (0.1 mg/ml in the drinking water) or voluntary exercise for 2 weeks caused only a small nonsignificant stimulation of UVB-induced increase in the percentage of phospho-p53 (Ser-15)-positive cells in the epidermis (27 or 18%, respectively), the combination of the two treatments enhanced the UVB-induced increase in phospho-p53 (Ser-15)-positive cells by 99%. The plasma concentration of caffeine in mice ingesting caffeine (0.1–0.4 mg/ml drinking water) is similar to that in the plasma of most coffee drinkers (one to four cups per day). Our studies indicate a greater than additive stimulatory effect of combined voluntary exercise and oral administration of a low dose of caffeine on UVB-induced apoptosis.
Disulfooxy fatty acids from the American bird grasshopper
Schistocerca americana
, elicitors of plant volatiles
Authors: Alborn Hans T. , Hansen Trond V. , Jones Tappey H. , Bennett Derrick C. , Tumlinson James H. , Schmelz Eric A. , Teal Peter E. A.
Published: July 2007

A previously unidentified class of compounds has been isolated from the regurgitant of the grasshopper species
Schistocerca americana
. These compounds (named here “caeliferins”) are composed of saturated and monounsaturated sulfated α-hydroxy fatty acids in which the ω-carbon is functionalized with either a sulfated hydroxyl or a carboxyl conjugated to glycine via an amide bond. The regurgitant contains a series of these compounds with fatty acid chains of 15–20 carbons and in varying proportions. Of these, the 16-carbon analogs are predominant and are also most active in inducing release of volatile organic compounds when applied to damaged leaves of corn seedlings. Caeliferins are nonlepidopteran elicitors identified in insect herbivores. This adds a category of insect herbivore-produced elicitors of plant responses, providing further evidence of the ability of plants to detect and respond to a broad range of insect herbivore-produced compounds.
Human hepatic stem cells from fetal and postnatal donors
Authors: Schmelzer Eva , Zhang Lili , Bruce Andrew , Wauthier Eliane , Ludlow John , Yao Hsin-lei , Moss Nicholas , Melhem Alaa , McClelland Randall , Turner William , Kulik Michael , Sherwood Sonya , Tallheden Tommi , Cheng Nancy , Furth Mark E. , Reid Lola M.
Published: July 2007

Human hepatic stem cells (hHpSCs), which are pluripotent precursors of hepatoblasts and thence of hepatocytic and biliary epithelia, are located in ductal plates in fetal livers and in Canals of Hering in adult livers. They can be isolated by immunoselection for epithelial cell adhesion molecule–positive (EpCAM+) cells, and they constitute ∼0.5–2.5% of liver parenchyma of all donor ages. The self-renewal capacity of hHpSCs is indicated by phenotypic stability after expansion for >150 population doublings in a serum-free, defined medium and with a doubling time of ∼36 h. Survival and proliferation of hHpSCs require paracrine signaling by hepatic stellate cells and/or angioblasts that coisolate with them. The hHpSCs are ∼9 μm in diameter, express cytokeratins 8, 18, and 19, CD133/1, telomerase, CD44H, claudin 3, and albumin (weakly). They are negative for α-fetoprotein (AFP), intercellular adhesion molecule (ICAM) 1, and for markers of adult liver cells (cytochrome P450s), hemopoietic cells (CD45), and mesenchymal cells (vascular endothelial growth factor receptor and desmin). If transferred to STO feeders, hHpSCs give rise to hepatoblasts, which are recognizable by cordlike colony morphology and up-regulation of AFP, P4503A7, and ICAM1. Transplantation of freshly isolated EpCAM+ cells or of hHpSCs expanded in culture into NOD/SCID mice results in mature liver tissue expressing human-specific proteins. The hHpSCs are candidates for liver cell therapies.
BAFF and MyD88 signals promote a lupuslike disease independent of T cells
Authors: Groom Joanna R. , Fletcher Carrie A. , Walters Stacey N. , Grey Shane T. , Watt Sally V. , Sweet Mathew J. , Smyth Mark J. , Mackay Charles R. , Mackay Fabienne
Published: July 2007

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the production of autoantibodies. However, the underlying cause of disease appears to relate to defects in T cell tolerance or T cell help to B cells. Transgenic (Tg) mice overexpressing the cytokine B cell–activating factor of the tumor necrosis factor family (BAFF) develop an autoimmune disorder similar to SLE and show impaired B cell tolerance and altered T cell differentiation. We generated BAFF Tg mice that were completely deficient in T cells, and, surprisingly, these mice developed an SLE-like disease indistinguishable from that of BAFF Tg mice. Autoimmunity in BAFF Tg mice did, however, require B cell–intrinsic signals through the Toll-like receptor (TLR)–associated signaling adaptor MyD88, which controlled the production of proinflammatory autoantibody isotypes. TLR7/9 activation strongly up-regulated expression of transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), which is a receptor for BAFF involved in B cell responses to T cell–independent antigens. Moreover, BAFF enhanced TLR7/9 expression on B cells and TLR-mediated production of autoantibodies. Therefore, autoimmunity in BAFF Tg mice results from altered B cell tolerance, but requires TLR signaling and is independent of T cell help. It is possible that SLE patients with elevated levels of BAFF show a similar basis for disease.
A/T mutagenesis in hypermutated immunoglobulin genes strongly depends on PCNAK164 modification
Authors: Langerak Petra , Nygren Anders O.H. , Krijger Peter H.L. , van den Berk Paul C.M. , Jacobs Heinz
Published: July 2007

B cells use translesion DNA synthesis (TLS) to introduce somatic mutations around genetic lesions caused by activation-induced cytidine deaminase. Monoubiquitination at lysine164 of proliferating cell nuclear antigen (PCNAK164) stimulates TLS. To determine the role of PCNAK164 modifications in somatic hypermutation, PCNAK164R knock-in mice were generated. PCNAK164R/K164R mutants are born at a sub-Mendelian frequency. Although PCNAK164R/K164R B cells proliferate and class switch normally, the mutation spectrum of hypermutated immunoglobulin (Ig) genes alters dramatically. A strong reduction of mutations at template A/T is associated with a compensatory increase at G/C, which is a phenotype similar to polymerase η (Polη) and mismatch repair–deficient B cells. Mismatch recognition, monoubiquitinated PCNA, and Polη likely cooperate in establishing mutations at template A/T during replication of Ig genes.
Labyrinthula terrestris: a new pathogen of cool‐season turfgrasses
Authors: OLSEN MARY W.
Published: July 2007

A new disease of turfgrass known as rapid blight is caused by Labyrinthula terrestris, a newly described member of the Labyrinthulids. This unusual group of microorganisms previously has been found in marine systems, and L. terrestris is the only member of the genus Labyrinthula known to be a pathogen of terrestrial plants. Members of this genus are defined by the formation of ectoplasmic networks in which the unicellular somatic cells move or ‘glide’. Infections of cool‐season turfgrasses occur most commonly when they are irrigated with suboptimal irrigation water with elevated salinity. Disease has been observed in 11 states in the United States and in the United Kingdom. A phylogenetic study indicates that isolates from turfgrass in the United States fall firmly within a clade containing other Labyrinthula spp. and that they came from a common lineage. Its rapid emergence as a turfgrass pathogen may coincide with increased use of relatively high‐salinity water or reclaimed water for irrigation. L. terrestris is a potential problem in susceptible turfgrass varieties wherever soil salinity is allowed to accumulate as a result of poor soil structure or suboptimal quality irrigation water is used for irrigation.
Unstable Asia: active deformation of Siberia revealed by drainage shifts
Authors: Allen Mark B. , Davies Clare E.
Published: July 2007

Regional incision and lateral shifts of rivers in the West Siberian Basin and surrounding areas show the action of long wavelength surface tilting, directed away from the Urals and Central Asian mountains and towards the Siberian Craton. In the north of the basin, surface uplift of individual folds is recorded by local lateral drainage migration. Lateral slopes of river valleys vary in gradient from 0.001 to 0.0001, generally decreasing with increasing river discharge. As a result of this surface deformation significant drainage shifts are taking place in three of the longest and highest discharge river systems on Earth: the Yenisei, Ob' and Irtysh. The deformation is most plausibly caused by subtle faulting at depth, below the thick basin fill of Mesozoic and Lower Cenozoic sediments. Active deformation of western Siberia appears to represent a previously unrecognised, far‐field effect of the India–Eurasia collision, up to ∼1500 km north of the limit of major seismicity and mountain building. It adds ∼2.5 × 106 km2 to the region deformed by the collision, which is an area greater than the Himalayas and Tibet combined. It is also an analogue for the formation of low‐angle unconformities in terrestrial sedimentary basins on the periphery of other orogenic belts.
High molecular weight adiponectin dominates in cord blood of newborns but is unaffected by pre‐eclamptic pregnancies
Authors: Odden Nancy , Mørkrid Lars
Published: July 2007

Objective  This study is the first to report high molecular weight (HMW) adiponectin in newborns from normal and pre‐eclamptic pregnancies (PE). Adiponectin is adversely related to Metabolic Syndrome‐linked diseases such as obesity, dyslipidaemia, insulin resistance and hypertension. It is abundant in human plasma where it circulates as several characteristic multimeric forms of which the HMW form is the most active. As children from PE‐pregnancies have a greater susceptibility to hypertensive disorders later in life, we hypothesized that adiponectin measured in cord blood could be a putative risk marker.

Design and patients  Cross‐sectional, hospital‐based study of newborns from mothers with pre‐eclampsia (30 cases and 62 controls). Venous cord blood samples were collected immediately after birth and were analysed for total adiponectin and HMW adiponectin.

Measurements  Total adiponectin and HMW adiponectin were measured by commercially available enzyme‐linked immunosorbent assay (ELISA) kits.

Results  The PE newborns showed a significantly lower gestational age (GA), total adiponectin and HMW adiponectin levels than the controls. No differences in adiponectin levels were found between case and control groups when correcting for GA. In combined groups, log (total adipo) = 0·40 + 0·027*GA; r = 0·43, P < 0·001. Furthermore, the HMW form is the dominant form of adiponectin: HMW adipo = –5·06 + 0·81*total adipo; r = 0·90, P < 0·001.

Conclusions  Adiponectin in cord blood from PE pregnancies may not be a tentative risk marker for Metabolic Syndrome‐linked diseases. HMW adiponectin is the dominant form of adiponectin in cord blood. Its role during pregnancy and postnatal life should be further explored.
The effects of metformin on metabolic and cardiovascular risk factors in nonobese women with polycystic ovary syndrome
Authors: Sahin Yilmaz , Unluhizarci Kursad , Yilmazsoy Ayse , Yikilmaz Ali , Aygen Ercan , Kelestimur Fahrettin
Published: July 2007

Objective  There are conflicting data regarding the effects of metformin in lean women with polycystic ovary syndrome (PCOS). Thus, our aim was to evaluate the effects of 6 months of metformin therapy on various metabolic and cardiovascular risk factors in lean women with PCOS.

Design  This was a prospective clinical study performed in a University hospital.

Patients  Twenty nonobese PCOS women and 20 age‐ and BMI‐matched healthy women were included in the study. Metformin (2550 mg/day) was administered for 6 months in women with PCOS. The hormonal and metabolic parameters were evaluated before and after metformin treatment.

Measurements  The main outcome measures were serum androgens, FSH, LH, oestradiol, 17‐hydroxyprogesterone, glucose, insulin, lipid profile, lipoprotein(a) [Lp(a)] and homocysteine levels. In addition 24‐h ambulatory blood pressure monitoring (ABPM) and carotid intima‐media thickness (IMT) were taken.

Results  After 6 months of metformin therapy, women with PCOS had decreased LH, total testosterone, free androgen index and slightly increased SHBG levels. Metformin treatment resulted in resumption of regular menses in 12 (60%) patients, and in 8 (40%) of them serum progesterone level was compatible with ovulation. Glucose and insulin responses to oral glucose tolerance test (OGTT) and homeostasis model assessment of insulin resistance (HOMA‐IR) did not improve after the metformin therapy. There were no significant changes in terms of cardiovascular risk factors such as lipids and homocysteine, IMT and ABPM.

Conclusion  Metformin may have beneficial effects in lean PCOS women in terms of resumption of menses without any remarkable effect on metabolic and cardiovascular risk factors.
Documentation of the nasal nitric oxide response to humming: methods evaluation
Authors: Shusterman D. J. , Jansen K. , Weaver E. M. , Koenig J. Q.
Published: July 2007

Rationale  Nitric oxide (NO) is present at higher concentrations in the nasal cavity than in the lower airway, and at even higher concentrations within the paranasal sinuses proper. When the paranasal sinus ostia are patent, acoustic activity produced by vocalization with closed lips (humming) promotes mixing of sinus with nasal gases, producing a further increase in nasal NO. We wished to evaluate procedures for the documentation of the nasal NO response to humming.

Materials and methods  We compared two ATS‐recommended sampling methods: 1) active exhalation of lower airway gas (parallel technique) and 2) passive aspiration of nasal gas with closed velopharynx (series technique). Variables controlled for included sampling rate, external resistance (parallel method), humming frequency, humming duration, and intertrial interval. Prior to upper airway sampling, exhaled lower airway NO was determined utilizing ATS‐standardized technique.

Results  Ten volunteers (seven males and three females, aged 21–58) with no history of respiratory allergies or sino‐nasal disease were studied in a single session each. The parallel technique documented an increase in nasal NO during the humming manoeuvre in all subjects (mean ratio of humming‐to‐quiet NO, 4·2), whereas the series technique did so in eight of 10 subjects (mean ratio 2·1). Correcting for admixture from the lower airway, the ratio of humming‐to‐quiet NO was greater with the parallel than series sampling technique (P < 0·05).

Conclusions  Documentation of the response of nasal NO to humming in subjects without sino‐nasal disease was consistently achievable by parallel sampling using commercially available equipment. Specific operational procedures are proposed.
In vitro antiangiogenic activity of selective somatostatin subtype‐1 receptor agonists
Authors: Bocci G. , Culler M. D. , Fioravanti A. , Orlandi P. , Fasciani A. , Colucci R. , Taylor J. E. , Sadat D. , Danesi R. , Del Tacca M.
Published: July 2007

Background  Endothelial cells of human blood vessels (arteries and veins) show high levels of somatostatin subtype‐1 receptor (sst1). The aim of the present study is to investigate the inhibitory effects of novel somatostatin analogs, highly selective for human sst1, on in vitro angiogenesis and their modulation of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor‐2 (VEGFR‐2) expression.

Materials and methods  Somatostatin analogs BIM‐23745 and BIM‐23926 were tested for their ability to prevent proliferation and migration of human endothelial HMEC‐1 cells, to modulate VEGF and VEGFR‐2 expression and to inhibit sprouting of microvessels from cultured human placental vessel explants in fibrin matrix for 28 days.

Results  The somatostatin sst1 receptor‐selective agonists, BIM‐23745 and BIM‐23926 showed a suppression of endothelial proliferation (e.g. 10−6 M BIM‐23475, 40·0 ± 2·1% vs. 100% of controls; 10−7 M BIM‐23926, 55·3 ± 3·3% vs. 100% of controls), migration (e.g. 10−7 M BIM‐23475, 35·0 ± 1·56% vs. 100% of controls; 10−7 M BIM‐23926, 53·7 ± 1·77% vs. 100% of controls) and microvessel sprouting (e.g. 10−8 M BIM‐23475, 42·8 ± 5·6% vs. 100% of controls; 10−7 M BIM‐23926, 17·2 ± 11·8% vs. 100% of controls). A small but significant percentage of cells exposed to BIM‐23745 and BIM‐23926 for 24 h and for 72 h presented typical apoptotic morphology. Moreover, both the analogs significantly inhibit VEGF and VEGFR‐2 gene expression in endothelial cells grown for 144 h in a fibrin matrix and the VEGF secretion in conditioned media.

Conclusions  The inhibition of endothelial activities suggests potential therapeutic utility for administration of somatostatin sst1 receptor‐selective agonists in the proliferative diseases involving angiogenesis.
Association of oxidative stress and PON1 with LDL and HDL particle size in middle‐aged subjects
Authors: Vekic J. , Kotur‐Stevuljevic J. , Jelic‐Ivanovic Z. , Spasic S. , Spasojevic‐Kalimanovska V. , Topic A. , Zeljkovic A. , Stefanovic A. , Zunic G.
Published: July 2007

Background  Alterations in plasma lipoprotein subclass distributions affect atherosclerosis risk. Smaller, denser low‐density lipoprotein (LDL) particles (sdLDL) are more susceptible to oxidation. In contrast, most of the protective effects of high‐density lipoproteins (HDL) are attributable to larger particles. This study investigates the connection between LDL and HDL particle heterogeneity and oxidative stress, antioxidative defence (AOD) and paraoxonase (PON1) status in a healthy middle‐aged Serbian population.

Materials and methods  LDL and HDL particle sizes and subclass distributions were measured by gradient gel electrophoresis in 104 men and 103 women, aged 53 ± 9·4 years. PON1 activities and PON1Q192R phenotypes were determined with paraoxon and diazoxon as substrates. The oxidative stress/AOD status was estimated by measuring malondialdehyde (MDA) and superoxide‐anion () levels and superoxide‐dismutase (SOD) activity.

Results  Subjects with sdLDL had significantly higher MDA (P < 0·001) and (P < 0·05) levels and greater diazoxonase (DZOase) activity (P < 0·05) compared to subjects with larger LDL particles. A high MDA concentration was a significant predictor of the sdLDL phenotype (P < 0·005). Increased levels of and MDA were associated with smaller HDL3 subclass abundance. Reduced HDL particle size was associated with lower DZOase activity (P < 0·01).

Conclusions  Even in the absence of symptoms of atherosclerosis, sdLDL particles are associated with increased oxidative stress, which may stimulate a compensatory rise in PON1 DZOase activity. Elevated oxidative stress may significantly affect HDL subclass distribution, resulting in the accumulation of smaller, denser HDL particles with diminished antioxidative capacity.
High‐dose versus low‐dose esomeprazole‐based triple therapy for Helicobacter pylori infection
Authors: Hsu P. I. , Lai K. H. , Wu C. J. , Tseng H. H. , Tsay F. W. , Peng N. J. , Chen T. A. , Chuah S. K. , Lin W. S. , Lo G. H.
Published: July 2007

Background  This prospective, randomized, controlled study was conducted to compare the efficacies of high‐dose and low‐dose esomeprazole‐based triple therapies for Helicobacter pylori eradication in Taiwan.

Materials and methods  From January 2004 to June 2006, 240 H. pylori‐infected patients were randomly assigned to undergo high‐dose (40 mg b.d.) or low‐dose (40 mg o.d.) esomeprazole combined with clarithromycin (500 mg b.d.) and amoxicillin (1 g b.d.) for one week. Follow‐up endoscopy was performed at eight weeks after the end of treatment to evaluate the response to therapy.

Results  Intention‐to‐treat analysis demonstrated no differences between eradication rates of high‐dose and low‐dose groups (92% vs. 90%, respectively, P > 0·05). Per‐protocol analysis yielded comparable results (95% vs. 93%). Both groups exhibited similar frequencies of adverse events (13% vs. 11%) and drug compliance (96% vs. 93%). Multivariate analysis indicated that only good compliance (odds ratio: 10·3, 95% CI, 3·0–35·7) was an independent predictor of treatment success.

Conclusions  This work demonstrates that low‐dose esomeprazole‐based triple therapy yields a similar eradication rate as high‐dose esomeprazole‐based therapy in Taiwan. Since the cost of the low‐dose regime is lower than that of the high‐dose regime, low‐dose esomeprazole‐based triple therapy can reasonably be recommended for the first‐line eradication of H. pylori for Taiwanese and probably most Asians.
Lipid peroxidation and mucin secretagogue activity in bile of gallstone patients
Authors: Jüngst C. , Sreejayan N. , Eder M. I. , Von Stillfried N. , Zündt B. , Spelsberg F. W. , Kullak‐Ublick G. A. , Jüngst D. , Von Ritter C.
Published: July 2007

Background  Chronic inflammation of the gallbladder wall and mucin hypersecretion are considered to be important factors in the pathogenesis of cholesterol gallstone disease. The aim of the study was to compare mucin concentration and mucin secretagogue activity with lipid peroxidation in gallbladder bile of patients with cholesterol or pigment stones.

Material and methods  We studied mucin concentration and, as a marker of lipid peroxidation, malondialdehyde concentration in 11 rapid (1 to 3 days) and eight non‐nucleating (> 21 days) gallbladder biles of patients with cholesterol or pigment stones. Furthermore, the mucin secretagogue activity of rapid and non‐nucleating gallbladder biles, as well as 1–5 µmol L−1 malondialdehyde on cultured gallbladder epithelial cells, was determined.

Results  Our data show an increased malondialdehyde (7·2 ± 1·8 vs. 3·8 ± 0·5 µmol L−1, P = 0·01) and mucin concentration (0·9 ± 0·09 vs. 0·41 ± 0·03 mg mL−1, P = 0·01) and an increased mucin secretagogue activity (2·0 ± 0·5 vs. 1·1 ± 0·3 mucin secretion/control, P = 0·04) and cholesterol saturation index (1·2 ± 0·1 vs. 08 ± 0·1, P = 0·04) in rapid as compared to non‐nucleating gallbladder biles. Malondialdehyde stimulated mucin secretion of cultured gallbladder epithelial cells in a concentration dependent manner.

Conclusions  Our results support a promoting effect of gallbladder mucin hypersecretion by lipid peroxidation leading to rapid formation of cholesterol crystals in gallbladder bile. These findings suggest that besides hypersecretion of cholesterol in bile, chronic inflammation of the gallbladder wall is implicated in the pathogenesis of cholesterol gallstone disease.
A comparative analysis of population structuring and genetic diversity in sympatric lineages of freshwater shrimp (Atyidae: Paratya): concerted or independent responses to hydrographic factors?
Authors: COOK BENJAMIN D. , BUNN STUART E. , HUGHES JANE M.
Published: July 2007

1. We determined whether two sympatric mitochondrial DNA (mtDNA) lineages of freshwater shrimp (Decapoda: Atyidae: Paratya australiensis) represent biological species and if they had concerted or independent population responses to hydrographic factors in small streams (the Granite Creeks) in southeastern Australia.

2. Allozyme data indicated the presence of two gene pools at sites where the P. australiensis lineages were co‐occurring and the gene pools were statistically assigned with high probability to each respective lineage. This indicated that these mtDNA lineages in P. australiensis were reproductively isolated and thus biological species.

3. Populations of both lineages were genetically homogeneous among lowland sites within streams, but were isolated by steep stream gradients among upland sites and for lowland–upland site comparisons. However, the magnitude of differentiation was markedly different between the two lineages. Allozyme diversity also differed between the two lineages, suggesting that they have different effective population sizes. Thus, differences in the magnitude of genetic divergence among populations were probably because of different life‐history characteristics, including dispersal ability and population size.

4. Genetic population structure was mostly temporally stable, despite the extreme effects of drought during the first year and substantial stream‐flow during the second. However, stable isotope analyses revealed greater local movement in both lineages during the second year, as greater hydrological connectivity provided more opportunities for dispersal. Thus, although lowland populations within streams were genetically homogeneous, stable isotope data indicated that connections may be sporadic and result from accumulated small‐scale movements among refugial pools.

5. Both lineages were therefore found to have similar small‐scale population responses to the unstable habitats of the Granite Creeks. Results highlight the importance of refugia for the capacity of biota to recover from drought and the need for multiple restored patches to reinstate natural population processes (e.g. resilience, recolonization) in degraded systems.
Identification of phytoplasmas in eggs, nymphs and adults of Scaphoideus titanus Ball reared on healthy plants
Authors: Alma A. , Bosco D. , Danielli A. , Bertaccini A. , Vibio M. , Arzone A.
Published: July 2007

A survey for the presence of aster yellows‐related phytoplasmas in the different life stages of Scaphoideus titanus was carried out by means of PCR and nested‐PCR assays. Using a phytoplasma 16Srl group‐specific primer pair followed by RFLP analysis of amplified products, we were able to detect and identify phytoplasmas from eggs, newly hatched nymphs, fourth and fifth instar nymphs and adults reared on ten phytoplasma‐free Vicia faba seedlings. Two of these broad beans became infected, whereas PCR failed to detect phytoplasmas in the same ten plants before leafhopper rearing. These results suggest the possibility of transovarial transmission of aster yellows‐related phytoplasmas in S. titanus.
Insulin‐mediated secretion of ecdysteroids from mosquito ovaries and molecular cloning of the insulin receptor homologue from ovaries of bloodfed Aedes aegypti
Authors: Graf R. , Neuenschwander S. , Brown M. R. , Ackermann U.
Published: July 2007

The reproductive cycle of female mosquitoes is activated by ingestion of blood from vertebrate hosts. Shortly after feeding, neurohormones are released from the brain neurosecretory system and stimulate the ovaries to secrete ecdysteroids, which are necessary for vitellogenesis by the fat body. Because bombyxins, which are insulin‐like peptides, stimulate ecdysteroidogenesis in silkworm larvae, we tested porcine insulin and found that it activates ecdysteroidogenesis and protein synthesis in ovaries isolated from unfed mosquitoes. To further characterize the regulation of ecdysteroidogenesis in female mosquitoes, we cloned the mosquito insulin receptor (MIR) homologue from ovarian mRNA. The sequence of the extracellular domain shows moderate homologies with vertebrate and Drosophlla Insulin receptor homologues, as well as with the insulin receptor‐related receptor, the latter being an ‘orphan’ receptor with an unknown function. In the intracellular domain, high homologies are observed, particularly in those subdomains that are responsible for ATP binding and kinase activity. Northern blot analysis of MIR demonstrated a highly specific expression in ovaries, and cloning experiments indicated its presence in the brain. Recombinant MIR extracts from a baculovirus expression system contained high constitutive kinase activity in the presence of manganese or magnesium. Activation was independent of a ligand. SDS‐gel analysis suggested that the recombinant receptor was not post‐translationally processed into an α and β‐subunit as was expected from a putative cleavage sinal. Enzymatic properties of the propreceptor are presented: the Km for ATP was between 15 and 50 μM in the presence of a synthetic substrate: maximal kinase activity to 100‐fold over basic activity was reached in the presence of 1 mn managanese. Stimulation of key oogenic processes by porcine insulin and identification of a MIR indicate that insulin‐like neurophormonones may have an important regulatory role in mosquito oogenesis.
Cysteine proteinase 1 (CP1), a cathepsin L‐like enzyme expressed in the Drosophila melanogaster haemocyte cell line mbn‐2
Authors: Tryselius Y. , Hultmark D.
Published: July 2007

We have isolated cDNA clones encoding the full‐length Drosophila melanogaster cysteine proteinase 1 (CP1). The clones were isolated from the Drosophila melanogaster haemocytic mbn‐2 cell line, where the gene is relatively strongly expressed, giving a transcript of 1.6 kb in size. We present the sequence encoding the full‐length protein, and deduce the genomic organlzation of the gene by comparison to previously published genomic partial sequence data. Immunofluorescence shows that CP1 is localized in small granules, probably lysosomes, in mbn‐2 cells. The data presented suggest a role for cysteine proteinases in immune functions in insects. It is likely to participate in the degradation of internalized material in phagocytic cells.
Pain, anxiety and powerlessness
Authors: Walding Mary F.
Published: July 2007

This paper explores the subject of postoperative pain, touching on the theories of the physiological mechanisms by which pain is perceived and exploring in some detail the literature on those factors which affect the pain experience. The need for a detailed assessment of the pain which an individual experiences is suggested by this study of the literature. This concept is explored in some detail. The author explores the relationship between pain and anxiety, commenting on that which affects patients undergoing surgery. The relationship between anxiety and perceived helplessness or powerlessness is also discussed. The paper concludes by drawing together the information from the literature reviewed and the author suggests a hypothesis that pain, anxiety and perceived powerlessness have an effect on each other. There is a suggestion that decreasing perception of powerlessness may decrease the intensity of the pain experience for the individual. It is suggested that is this is an area for future research into postoperative pain management.
Clinical decision making in nursing
Authors: Harbison Jean
Published: July 2007

In this paper, the author reflects on the new practitioner envisaged by developers of the Project 2000 curriculum in Scotland, and focuses on the need to develop critical thinking ability, in particular in relation to clincal decision making. Two approaches to decision making are outlined: the rationalist perspective and the phenomenological perspective, and a model illustrating each is discussed. The models examined are, respectively, decision analysis and hypothetico‐deductive reasoning, and their relevance to nursing outlined. The author concludes by discussing the nursing process model from both perspectives; and by recommending that nurses learn from the work done by other disciplines on professional judgement. The suggested role of Nurse teacher in preparing the new practitioner is outlined.
Primary nursing and the role of the nurse preceptor in changing long‐term mental health care: an evaluation
Authors: Armitage Paul , Champney‐Smith Jeff , Andrews Kathy
Published: July 2007

The main aims of this action research study were to implement primary nursing in two long‐term psychiatric rehabilitation/continuing‐care wards and to investigate the effects of the intervention on the quality of nursing care provision. This evaluation took the form of a quasi‐expermental time series analysis. A package of measures together with a number of peripheral indicators was used before primary nursing was introduced on each ward and again after primary nursing had become established. The results showed that the implementation of primary nursing led to nurses being more accountable for care, residents who were seen to be more self‐sufficient and independent and wards which had an improved enviornment for care and rehabilitation.