bluuebunny/crossref_metadata_2025 huggingface dataset:
RestoringQuercus pyrenaicaforests using pioneer shrubs as nurse plants
Authors: Castro Jorge , Zamora Regino , Hódar José A.
Published: February 2009

Question:How to improve reforestation success ofQuercus pyrenaica.

Location:1800 m a.s.L, southern Spain.

Methods:One‐year‐oldQuercus pyrenaicaseedlings were planted using two treatments: (1) bare soil, using a 30‐cm diameter augur bit (conventional technique) and (2) under the canopy of a pioneer shrub,Salvia lavandulifolia, using a 12‐cm diameter augur bit. Survival and growth were monitored for six years. Our hypothesis is that the use of shrubs as nurse plants is an alternative technique of reforestation with higher success than traditional techniques, in which pre‐existing vegetation is usually considered a source of competition. The rationale for the study was that for environments with a dry season, pre‐existing vegetation buffers summer drought stress, ameliorates the water status of seedlings and thus usually increases seedling recruitment.

Results:Quercussurvival was 6.3 × higher when planted under individuals of the pioneer shrub as compared to open areas.Quercusseedlings under shrubs also had shoots 1.8 X longer, while the number of shoots per plant did not differ among treatments. The first summer was the period with the highest mortality (49.1% of seedlings). Summer drought was the main cause of mortality.

Conclusions:The use of shrubs as nurse plants forQ.pyrenaicareforestation is a viable technique to increase establishment success. The technique could be similarly useful in other environments with a dry period and for otherQuercusspecies. In addition, this technique offers the advantage of following natural succession, thus minimizing the impact in the community.
Transition from P‐ to N‐limited phytoplankton growth in an artificial lake on flooded cutaway peatland in Ireland
Authors: Higgins T. , Colleran E. , Raine R.
Published: February 2009

Question: Which nutrient limits primary production in a lake created by flooding industrial cutaway peatland?

Location: Clongawny Lake (53°10’N, 07°53’W), County Offaly, Ireland

Methods: Nutrient concentrations in lake water and the dynamics of phytoplankton populations were monitored over a 38‐month period. The ratio of dissolved inorganic nitrogen to total phosphorus (DIN:TP) and nutrient enrichment bio‐assays were used to investigate temporal changes in nutrient limitation.

Results: Primary production in the new lake was phytoplankton‐driven due to the scarcity of recolonizing macrophytes. Phytoplankton growth was initially phosphorus‐limited. The runoff of phosphate fertilizer from an adjacent coniferous forestry plantation raised the TP concentration of lake water 5.5‐fold. Consequently, the biovolume of phytoplankton increased 30‐fold, and chlorophyll‐a concentrations increased eightfold, reaching hyper‐eutrophic levels. A concurrent depletion of nitrogen in lake water reduced the DIN:TP ratio from 17.8 to 0.6, and phytoplankton growth rapidly became nitrogen‐limited. Phytoplankton composition shifted from dinoflagellates to minute, unicellular chlorophytes, with a coincident decline in species diversity. Cyanobacteria did not proliferate, most likely due to the acidic nature of the lake.

Conclusions: Results illustrated the vulnerability of newly created cutaway peatland lakes to developing severe phytoplankton blooms and coincident secondary nitrogen limitation in the presence of moderate external phosphorus inputs.
Competition as a factor structuring species zonation in riparian fens ‐ a transplantation experiment
Authors: Kotowski Wiktor , Thörig Werner , van Diggelen Rudy , Wassen Martin Joseph
Published: February 2009

Question: What is the relative importance of competition and physical factors in restricting the occurrence of different fen species to certain zones of the riparian landscape?

Location: Biebrza National Park, NE Poland.

Methods: We carried out a two‐season reciprocal transplantation experiment: sod‐blocks were replaced between a low‐productive groundwater‐fed small‐sedge fen and a high‐productive fluviogenous tall‐sedge fen. Five treatments were applied to the transplanted sods: (1) no manipulation; (2) fertilization with NPK to exclude the effect of nutrient limitation; (3) clipping vegetation around the transplant to exclude competition for light; (4) clipping + fertilizing; (5) sods were also transplanted within their own environment.

Results: After two seasons, the small‐sedge sods transplanted into the high‐productive zone had a biomass two times lower than that of the control transplants, mainly due to a decrease in small sedges and bryophytes. Tall sedges of the high‐productive zone did not respond significantly to transplantation in the low‐productive zone. Removal of the surrounding vegetation largely enhanced the growth of small sedges and bryophytes and, to a lesser degree, of tall sedges. Fertilization, on the other hand, resulted in increased growth of tall sedges, grasses and non‐graminoid herbs.

Conclusion: Species characteristic of low‐productive fen communities are competitively excluded from the high‐productive zone through light competition. In contrast, the performance of tall sedges in the low‐productive zone is lowered by nutrient limitation. In the long run this may lead to a complete disappearance of these species from this zone. We did not find evidence that the physical stress of flooding has a direct effect on the performance and distribution of species. Results from the experiment suggest that productivity gradients and their influence on competition intensity are of primary importance for structuring vegetation patterns in lowland riparian fens.
Restoring prairie pothole wetlands: does the species pool concept offer decision‐making guidance for re‐vegetation?
Authors: Galatowitsch Susan M.
Published: February 2009

Question: Do regional species pools, landscape isolation or on‐site constraints cause plants from different guilds to vary in their ability to colonize restored wetlands?

Location: Iowa, Minnesota, and South Dakota, USA.

Methods: Floristic surveys of 41 restored wetlands were made three and 12 years after reflooding to determine changes in local species pools for eight plant guilds. The effect of landscape isolation on colonization efficiency was evaluated for each guild by plotting local species pools against distance to nearby natural wetlands, and the relative importance of dispersal vs. on‐site constraints in limiting colonization was explored by comparing the local species pools of restored and natural wetlands within the region.

Results: Of the 517 wetland plant taxa occurring in the region, 50% have established within 12 years. The proportion of the regional species pool represented in local species pools differed among guilds, with sedge‐meadow perennials, emergent perennials and floating/submersed aquatics least represented (33‐36%) and annual guilds most represented (74‐94%). Colonization‐to‐extinction ratios suggest that floating/submersed aquatics have already reached a species equilibrium while sedge‐meadow and emergent perennials are still accumulating species. Increasing distance to nearest wetlands decreased the proportion of the regional species pool present in local pools for all guilds except native annuals and woody plants. The maximum proportion predicted, assuming no distance constraint, was comparable to the lowest‐diversity natural wetlands for most perennial guilds, and also lower than what was achieved in a planted, weeded restoration.

Conclusions: A biotic constraints seem to limit the colonization of floating/submersed aquatics into natural or restored wetlands, whereas all other guilds are potentially constrained by dispersal or biotic factors (i.e. competition from invasive species). Using species pools to evaluate restoration progress revealed that immigration potential varies considerably among guilds, that local species richness does not necessarily correspond to immigration limitations, and that some guilds (e.g. sedge‐meadow perennials) will likely benefit more than others from being planted at restoration sites.
Prediction of herbage yield in grassland: How well do Ellenberg N‐values perform?
Authors: Wagner Markus , Kahmen Ansgar , Schlumprecht Helmut , Audorff Volker , Perner Jörg , Buchmann Nina , Weisser Wolfgang W.
Published: February 2009

Question: How useful are Ellenberg N‐values for predicting the herbage yield of Central European grasslands in comparison to approaches based on ordination scores of plant species composition or on soil parameters?

Location: Central Germany (11°00′‐11°37’E, 50°21‐50°34’N, 500–840 m a.s.l.).

Methods: Based on data from a field survey in 2001, the following models were constructed for predicting herbage yield in montane Central European grasslands: (1) Linear regression of mean Ellenberg N‐, R‐ and F‐values; (2) Linear regression of ordination scores derived from Non‐metric Multidimensional Scaling (NMDS) of vegetation data; and (3) Multiple linear regression (MLR) of soil variables. Models were evaluated by cross‐validation and validation with additional data collected in 2002.

Results: Best predictions were obtained with models based on species composition. Ellenberg N‐values and NMDS scores performed equally well and better than models based on Ellenberg R‐ or F‐values. Predictions based on soil variables were least accurate. When tested with data from 2002, models based on Ellenberg N‐values or on NMDS scores accurately predicted productivity rank order of sites, but not the actual herbage yield of particular sites.

Conclusions: Mean Ellenberg N‐values, which are easy to calculate, are as accurate as ordination scores in predicting herbage yield from plant species composition. In contrast, models based on soil variables may be useful for generating hypotheses about the factors limiting herbage yield, but not for prediction. We support the view that Ellenberg N‐values should be called productivity values rather than nitrogen values.
Management of three endangered plant species in dynamic Baltic seashore meadows
Authors: Rautiainen P. , Björnström T. , Niemelä M. , Arvola P. , Degerman A. , Erävuori L. , Siikamäki P. , Markkola A. , Tuomi J. , Hyvärinen M.
Published: February 2009

Question:
Arctophila fulva var. pendulina, Primula nutans var. jokelae and Puccinellia phryganodes are threatened early successional species growing in the seashore meadows of the northern Baltic Sea. Patches formed by these species are destined to be replaced by other species during primary succession and in order to persist in the area they have to continuously colonize new areas. We studied whether the displacement of the species could be slowed down and their sexual and/or vegetative reproduction enhanced by management targeted to surrounding vegetation.

Location: Bothnian Bay, Baltic Sea, W Finland.

Methods: Vegetation surrounding patches of all study species was mown in four successional growing seasons. Moreover, the impact of additional soil turning on creating new favourable growing sites was tested for A. fulva.

Results: Deterioration of suitable habitats of A. fulva and P. nutans was markedly slowed down by management and the vegetative and/or sexual reproduction of these species was enhanced. In the case of P. phryganodes, however, no positive response to management was obtained.

Conclusions: In order to improve the long‐term persistence of these three species successional vegetation changes should be slowed down and their dispersal and colonization success improved by continuous management of the populations. We further suggest that the colonization of new areas should be aided by transplantations to the non‐vegetated islets, which have recently risen from the sea and cannot be reached by means of dispersal.
Simulating the impacts of southern pine beetle and fire on the dynamics of xerophytic pine landscapes in the southern Appalachians
Authors: Waldron J.D. , Lafon C.W. , Coulson R.N. , Cairns D.M. , Tchakerian M.D. , Birt A. , Klepzig K.D.
Published: February 2009

Question: Can fire be used to maintain Yellow pine (Pinus subgenus Diploxylon) stands disturbed by periodic outbreaks of southern pine beetle?

Location: Southern Appalachian Mountains, USA.

Methods: We used LANDIS to model vegetation disturbance and succession on four grids representative of xeric landscapes in the southern Appalachians. Forest dynamics of each landscape were simulated under three disturbance scenarios: southern pine beetle, fire, and southern pine beetle and fire, as well as a no disturbance scenario. We compared trends in the abundance of pine and hardwood functional types as well as individual species.

Results: Yellow pine abundance and open woodland conditions were best maintained by a combination of fire and southern pine beetle disturbance on both low elevation sites as well as mid‐elevation ridges & peaks. On mid‐elevation SE‐W facing slopes, pine woodlands were best maintained by fire alone.

Conclusions: Our simulations suggest that fire can help maintain open pine woodlands in stands affected by southern pine beetle outbreaks.
Sampling plant functional traits: What proportion of the species need to be measured?
Authors: Pakeman Robin J. , Quested Helen M.
Published: February 2009

Question: Understanding functional change in vegetation and how it might impact on vegetation change and ecosystem function entails measuring plant traits and attributes in situ. However, it is not realistically possible to sample every species for every trait, hence we need to address the consequences of not sampling all species.

Location: Nine arable and grassland sites from the machair of the Western Isles, UK and twenty grassland and woodland sites from Nynäs Nature Reserve, southern Sweden.

Methods: The effects of progressively reducing the proportion of species used to estimate the weighted mean of a range of continuous and qualitative traits were assessed.

Results: Relative abundance and species traits were related, and hence there is a cost in accuracy in reducing the number of species sampled in estimating the weighted mean for the vegetation. This cost was higher for qualitative traits than quantitative ones.

Conclusion: The analysis suggested that for the quantitative traits a minimum of those species that make up at least 80% of the vegetation should be sampled if traits do not vary greatly between species. If this variability is high and the trait is likely to be correlated to abundance then greater effort in sampling species for traits is required. Qualitative information on the rarer species should still be entered into the analysis if it can be accessed in any way, even if quantitative information for that species is unavailable.
Long‐term effectiveness of sowing high and low diversity seed mixtures to enhance plant community development on ex‐arable fields
Authors: Lepŝ Jan , Doleẑal Jiri , Bezemer T. Martijn , Brown Valerie K. , Hedlund Katarina , Igual Arroyo Mariano , Jörgensen Helene Bracht , Lawson Clare S. , Mortimer Simon R. , Peix Geldart Alvaro , Rodríguez Barrueco Claudino , Santa Regina Ignacio , Ŝmilauer Petr , van der Putten Wim H.
Published: February 2009

Questions: How is succession on ex‐arable land affected by sowing high and low diversity mixtures of grassland species as compared to natural succession? How long do effects persist?

Location: Experimental plots installed in the Czech Republic, The Netherlands, Spain, Sweden and the United Kingdom.

Methods: The experiment was established on ex‐arable land, with five blocks, each containing three 10 m × 10 m experimental plots: natural colonization, a low‐ (four species) and high‐diversity (15 species) seed mixture. Species composition and biomass was followed for eight years.

Results: The sown plants considerably affected the whole successional pathway and the effects persisted during the whole eight year period. Whilst the proportion of sown species (characterized by their cover) increased during the study period, the number of sown species started to decrease from the third season onwards. Sowing caused suppression of natural colonizing species, and the sown plots had more biomass. These effects were on average larger in the high diversity mixtures. However, the low diversity replicate sown with the mixture that produced the largest biomass or largest suppression of natural colonizers fell within the range recorded at the five replicates of the high diversity plots. The natural colonization plots usually had the highest total species richness and lowest productivity at the end of the observation period.

Conclusions: The effect of sowing demonstrated dispersal limitation as a factor controlling the rate of early secondary succession. Diversity was important primarily for its‘insurance effect’: the high diversity mixtures were always able to compensate for the failure of some species.
Spatial distribution patterns of Rhynchostegium megapolitanum at the landscape scale ‐ an expanding species?
Authors: Zechmeister Harald G. , Moser Dietmar , Milasowszky Norbert
Published: February 2009

Question: Is Rhynchostegium megapolitanum an expanding species?

Location: Viennese Basin (120‐220 m a.s.1.), Austria.

Methods: 121 dry grasslands, were investigated for the occurrence of R. megapolitanum. Nineteen environmental variables at 50 randomly selected sites, species composition at sites with and without R. megapolitanum and the spatial patterns of distribution of the species at the landscape scale were analysed. We compared actual distribution data of three rare species (Didymodon acutus, Pleurochaete squarrosa R. megapolitanum) and a common one (Brachythecium rutabulum) with the distribution obtained by vouchers that were collected between 1860 and 1940 in the investigated area. We calculated a GIS based model pattern and compared it with the actual distribution.

Results:
R. megapolitanum was detected in 28 of these sites, almost 50 % of its populations produced sporophytes. We found significant differences between sites with and without R. megapolitanum with regard to grassland size, the percentage of silt and of sand in the soil. There were fewer occurrences of historic herbarium vouchers of R. megapolitanum than our current field survey discovered. The GIS based analyses of distribution patterns at the landscape scale showed a clustering of sites in which R. megapolitanum was present or absent. Simulations with a spatially realistic expansion model showed high similarities to the actual distribution of the species.

Conclusions: All these analyses suggest that R. megapolitanum has been expanding in the investigated area. A significant increase in temperature and nitrogen deposition within the last hundred years might be the underlying cause for the species' spread.
The impact of Rhinanthus minor in newly established meadows on a productive site
Authors: Westbury Duncan B. , Dunnett Nigel P.
Published: February 2009

Question: What is the impact of the presence of Rhinanthus minor on forb abundance in newly established swards?

Location: Wetherby, West Yorkshire, UK (53°55’N, 1°22’W).

Method: A standard meadow mix containing six forbs and six grasses was sown on an ex‐arable field and immediately over‐sown using a randomised plot design with three densities of Rhinanthus minor (0, 600, and 1000 seeds per m2). Above‐ground biomass was analysed over a period of three years, while detailed assessments of sward composition were performed during the first two years.

Results: Values of grass biomass were reduced in the presence of Rhinanthus, especially at the higher sowing density. The ratio of grass: forb biomass was also lower in association with Rhinanthus, but only at the higher sowing density. The presence of Rhinanthus had no effect on species number or diversity, which decreased between years regardless of treatment.

Conclusions: Although not tested in a multi‐site experiment, the benefit of introducing Rhinanthus into newly established swards to promote forb abundance was determined. The efficacy of Rhinanthus presence is likely to depend on whether species not susceptible to the effects of parasitism are present.
Small‐scale spatial associations betweenArtemisia frigidaandPotentilla acaulisat different intensities of sheep grazing
Authors: Zhenguo Liu , Li Zhenqing , Ming Dong , Ivan Nijs , Jan Bogaert , El‐Bana Magdy I.
Published: February 2009

Questions:The formerly overgrazed Inner Mongolia steppe was subject to retrogressive succession. Today,Artemisia frigidaandPotentilla acaulisare two dominant species in different phases of successive degradation. To investigate the impact of grazing intensity on spatial community structure, we investigated the small‐scale spatial association betweenA. frigidaandP. acaulisat zero, light, medium and heavy sheep grazing, and proposed factors involved in the spatial associations between these two species along a grazing intensity gradient.

Location:The Inner Mongolia Grassland Ecosystem Research Station of the Chinese Academy of Sciences.

Methods:Four grazing intensities were selected: zero, light (1.33 sheep/ha), medium (4.0 sheep/ha) and heavy (6.7 sheep/ha). After 13 years of grazing three 2 m × 2 m quadrats with 100 × 100 cells of size 2 cm × 2 cm were randomly selected in each treatment in July and August 2002. The presence ofA. frigidaandP. acaulisin each cell was recorded and the positions of the individuals were mapped using Cartesian coordinates in each quadrat. The small‐scale spatial associations betweenA. frigidaorP. acauliswere quantified with theL12(d), J12(d)functions (both derived fromK12(d), the former indicating the type of the spatial association, the latter indicating the strength of the spatial association), using Monte Carlo simulations.

Results:A. frigidawas negatively associated withP. acaulisat short distances (0–100 cm) under zero and light grazing, and negatively or independently under medium and heavy grazing. Increasing grazing intensities suppressed the peak negative associations. More intense grazing enhanced the tendency towards independent distribution of these two species.

Conclusions:The small‐scale spatial associations betweenA. frigidaandP. acauliswere significantly different at four different intensities of sheep grazing. Grazing disturbance, clonal growth habit of species, and interspecific competition are the main factors leading to a difference of spatial associations between these two species at different grazing intensities.
A study of microRNAs in silico and in vivo: bioinformatics approaches to microRNA discovery and target identification
Authors: Yousef Malik , Showe Louise , Showe Michael
Published: February 2009

The discovery that microRNAs (miRNAs) are synthesized as hairpin‐containing precursors and share many features has stimulated the development of several computational approaches for identifying new miRNA genes in various animal species. Many of these approaches rely heavily on conservation of sequence within and between species, whereas others emphasize machine‐learning methods to screen hairpin candidates for structural features shared with known miRNA precursors. The identification of animal miRNA targets is a particularly difficult problem because an exact match to the target sequence is not required. We discuss the most recently devised algorithms for miRNA and target discovery. We do not discuss plant miRNAs because their varying sizes and structural characteristics pose different problems of identification and target selection.
A study of microRNAs in silico and in vivo: diagnostic and therapeutic applications in cancer
Authors: Waldman Scott A. , Terzic Andre
Published: February 2009

There is emerging evidence of the production in human tumors of abnormal levels of microRNAs (miRNAs), which have been assigned oncogenic and/or tumor‐suppressor functions. While some miRNAs commonly exhibit altered amounts across tumors, more often, different tumor types produce unique patterns of miRNAs, related to their tissue of origin. The role of miRNAs in tumorigenesis underscores their value as mechanism‐based therapeutic targets in cancer. Similarly, unique patterns of altered levels of miRNA production provide fingerprints that may serve as molecular biomarkers for tumor diagnosis, classification, prognosis of disease‐specific outcomes and prediction of therapeutic responses.
A study of microRNAs in silico and in vivo: bioimaging of microRNA biogenesis and regulation
Authors: Kim Soonhag , Hwang Do W. , Lee Dong S.
Published: February 2009

Many recent studies have reported that microRNA (miRNA) biogenesis and function are related to the molecular mechanisms of various clinical diseases. Several methods, including northern blotting and DNA chip analyses, are capable of assessing miRNA‐production patterns in cells. However, the development of repetitive monitoring of the miRNA‐production profile in a noninvasive manner is demanded for the application of miRNAs to human medicine. Here, we describe a noninvasive system for monitoring miRNA biogenesis, from the stage of primary transcripts to that of mature miRNA regulation. We review the optical methods that have been developed to image miRNA production at each step of the miRNA‐processing pathway in living subjects. We propose that an optical miRNA‐imaging strategy, based on molecular imaging, can be used as an miRNA imaging detector to monitor various miRNAs, by using different reporters, simultaneously, for high‐throughput screening, and will provide potential application for the diagnosis and therapeutics of multiple diseases.
Sexual and Reproductive Health Knowledge in Cystic Fibrosis Female Patients and Their Parents
Authors: Korzeniewska Aleksandra , Grzelewski Tomasz , Jerzyńska Joanna , Majak Paweł , Sołoniewicz Anna , Stelmach Włodzimierz , Stelmach Iwona
Published: February 2009

Introduction

The changing outcomes for young cystic fibrosis (CF) patients means that reproductive health issues have become an integral part of CF management.

Aim

The aim of this study was to investigate the knowledge and experiences of reproductive and sexual health issues in women with CF and to investigate the knowledge and reproductive health attitudes of their parents.

Main Outcome Measures

Assessment of reproductive and sexual health knowledge in female CF patients and their parents.

Methods

A questionnaire study directed to 120 Polish women with CF aged 16 years and older and their parents.

Results

Sixty-four patients and their parents responded to the questionnaire. Sixty-eight percent of the patients started sexual intercourse at a mean age of 19.2 years. Eighty-four percent of all sexually active women reported that they did not use any form of contraception. Only 32.8% of women understood the problems connected with their own and male fertility in CF. Popular scientific publications and other CF patients were identified as the most important source of information. Only 23% of parents understood the problems connected with female fertility in CF; 44% of parents thought that man with CF had normal fertility. Seventy-five percent of the women and 40% of the parents felt that sexual health discussions should begin between age 12 and 14 years with a CF doctor and the mother.

Conclusions

Our study showed that significant knowledge gaps exist regarding fertility issues in both CF patients and CF parents. Women with CF have some general knowledge about sexual issues but insufficient knowledge to have a safe sexual life. The results helped us to develop the educational program for CF patients.
Correlation of Degree of Penile Curvature between Patient Estimates and Objective Measures among Men with Peyronie’s Disease
Authors: Bacal Vanessa , Rumohr John , Sturm Renea , Lipshultz Larry I. , Schumacher Michael , Grober Ethan D.
Published: February 2009

Introduction

Among men with Peyronie’s disease (PD), the degree of penile curvature has significant implications on psychological well-being, sexual function, treatment planning, and posttherapy evaluations.

Aim

The primary objective of the current study was to correlate patients’ estimates of penile angulation with objective measures.

Main Outcome Measures

(i) Proportion of patients over- or underestimating their actual degree of curvature; and (ii) degree differences between patient estimates and objective measures of penile curvature.

Methods

At baseline, patients with established PD were asked to provide a “best estimate” of their degree of penile curvature. Objective measures of penile angulation were then performed using standardized photographs and protractor-based measurement of penile curvature during full erection. Correlations were performed between patient estimates of penile curvature and objective measures of penile angulation.

Results

Eighty-one men with established PD and a mean age of 52 years (range: 20–72 years) were prospectively evaluated. Mean duration of disease was 33 months (range: 6–276 months), and mean plaque size was 1.4 cm ± 0.1 standardized error (SE). The proportion of patients with dorsal, lateral, and ventral curvatures was 39%, 57%, and 4%, respectively. Patient estimates of baseline penile curvature (mean 51 degrees ± 3.1 SE) differed significantly from objective measurements (mean 40 degrees ± 2.4, P = 0.001). A significantly higher proportion of patients overestimate their actual degree of penile curvature (54% overestimate, 26% underestimate, and 20% are accurate within 5 degrees, P = 0.002). Compared with objective measures, patients’ estimates of degree of penile curvature differed by an average of 20 degrees ± 2.2 SE.

Conclusions

Patients with PD tend to overestimate their degree of penile curvature. Objective measurement of penile angulation is necessary to accurately counsel patients regarding disease severity, recommend appropriate treatment strategies, and objectively evaluate outcomes following therapy.
Phosphodiesterase Type 5 Regulation in the Penile Corpora Cavernosa
Authors: Lin Ching-Shwun
Published: February 2009

Introduction

Penile detumescence depends on the hydrolysis of cyclic guanosine monophosphate (cGMP) by phosphodiesterase type 5 (PDE5). It is hoped that a review of publications relevant to the regulation of PDE5 in the penis will be helpful to both scientists and clinicians who are interested in the sciences of erectile function/dysfunction.

Aims

The aim of this article is to comprehensively review the mechanisms by which PDE5 activity and expression in the penis are regulated. All published studies relevant to PDE5 regulation in the penis or penile cells will be reviewed.

Methods

Entrez (PubMed) was used to search for publications relevant to the topics of this review. Keywords used in the searches included vascular, cavernous, penis, smooth muscle, signaling molecules, erection, priapism, and PDE5. Articles that are dedicated to the study of erectile function/dysfunction were prioritized for citation.

Results

Regulation of PDE5 can occur at both protein and gene levels. At protein level, PDE5 is activated by phosphorylation and/or allosteric cGMP binding. Deactivation is carried out by protein phosphatase 1 and thus linked to the Rho-kinase signaling pathway. Cleavage of PDE5 into an inactive form has been shown as carried out by caspase-3. At the gene level, PDE5 expression is regulated at two alternative promoters, PDE5A and PDE5A2, both of which are positively regulated by cyclic adenosine monophosphate and cGMP. Downregulation of PDE5 has been observed in the penis of castrated animals; however, proof of androgen regulation of PDE5 gene requires examination of the smooth muscle content. Hyperoxia and hypoxia, respectively, regulate PDE5 expression positively and negatively. Hypoxic downregulation of PDE5 is a possible mechanism for the development of priapism.

Conclusions

PDE5 can be regulated at protein and gene levels. In the penis, changes of PDE5 activity have been linked to its phosphorylation status, and downregulation of PDE5 expression has been associated with hypoxia.
Erectile Function in Two-Kidney, One-Clip Hypertensive Rats is Maintained by a Potential Increase in Nitric Oxide Production
Authors: Linder A. Elizabeth , Dorrance Anne M. , Mills Thomas M. , Webb R. Clinton , Leite Romulo
Published: February 2009

Introduction

Hypertension is closely associated with erectile dysfunction (ED) as it has been observed in many experimental models of hypertension. Additionally, epidemiological studies show that approximately a third of hypertensive patients have ED.

Aim

To test the hypothesis that the two-kidney, one-clip (2K-1C) rat model of hypertension displays normal erectile function due to increased nitric oxide (NO) production in the penis.

Methods

Ganglionic-induced increase in intracavernosal pressure (ICP)/mean arterial pressure (MAP) ratio was used as an index of erectile function in 2K-1C and in normotensive sham-operated (SHAM) anesthetized rats. Cavernosal strips from hypertensive and normotensive rats were used for isometric tension measurement. The contraction induced by alpha-adrenergic agonist phenylephrine and the relaxation induced by the NO donor sodium nitroprusside (SNP) and by the Rho-kinase inhibitor Y-27632 were performed in the absence and in the presence of the NO synthase inhibitor Nω-nitro-L-arginine (L-NNA).

Results

Changes in ICP/MAP induced by ganglionic stimulation were not different between 2K-1C and SHAM rats. The contractile response induced by phenylephrine as well as the relaxation induced by SNP or the Y-27632 were similar in cavernosal strips from both groups. However, in the presence of L-NNA, the relaxation induced by Y-27632 was significantly impaired in 2K-1C compared to SHAM.

Conclusions

/These data suggest that hypertension and ED could be dissociated from high levels of blood pressure in some animal models of hypertension. Erectile function in 2K-1C hypertensive rats is maintained in spite of the increased Rho-kinase activity by increased NO signaling.
The Role of Opiorphins (Endogenous Neutral Endopeptidase Inhibitors) in Urogenital Smooth Muscle Biology
Authors: Davies Kelvin Paul
Published: February 2009

Introduction

The opiorphins are a newly characterized class of peptides that act as potent endogenous neutral endopeptidase (NEP) inhibitors. Recent reports have suggested that they play an important role in erectile physiology.

Aim

This article reviews recent developments that increase our understanding of the role of the opiorphin family of peptides in erectile physiology.

Methods

During a microarray screen of gene changes that occur in a rat diabetic model of erectile dysfunction (ED), Vcsa1 was one of the most down-regulated genes in the rat corpora. Quantitative real-time polymerase chain reaction demonstrated that in at least three models of diseases that result in ED (diabetes, aging, and cavernous nerve [CN] transection), Vcsa1 was down-regulated in the rat corpora. The human opiorphin family of genes (hSMR3A/B and ProL1) also acts as markers of erectile function in patients with ED.

Main Outcome Measures

The reader will be informed of the most current research regarding the role of opiorphins in urogenital smooth muscle biology.

Results

These observations led to the suggestion that genes encoding opiorphins (and potentially their peptide products) can act as markers of ED. Gene transfer of plasmids overexpressing Vcsa1 in aging rats, as well as intracorporal injection of sialorphin, led to an improvement in erectile function. In organ bath studies, we demonstrated that sialorphin can cause increased rates of relaxation of corporal smooth muscle (CSM). We have also demonstrated that in vitro, Vcsa1 causes changes in the expression of G-protein-coupled receptors (GPCRs). This has led us to suggest that the action of Vcsa1 on erectile physiology may act through relaxation of CSM by its ability to act as an inhibitor of NEP, therefore prolonging the action of peptide agonists at their GPCRs.

Conclusions

Overall, there is a growing body of evidence that the opiorphins play a role in regulating CSM tone and thereby erectile function.
Angiotensin II Signaling and Its Implication in Erectile Dysfunction
Authors: Jin Li-Ming
Published: February 2009

Introduction

Angiotensin II (Ang II) is the primary effector of the renin–angiotensin system (RAS). Ang II exerts its diverse physiologic actions via angiotensin type 1 and type 2 receptors. Recent evidence shows that tissue RAS exists in the penis, therefore indicating a significant role for Ang II in erectile function.

Aim

To summarize the recent findings on the importance of Ang II in normal erection physiology and the pathogenesis of erectile dysfunction (ED).

Methods

This article reviews the literature that relates to the role of RAS in the regulation of erectile function.

Main Outcome Measures

Evidence in the literature on the association between Ang II and the development of ED.

Results

Elevated Ang II levels contribute to the development of ED in humans and different animal models. Pharmacologic therapy interrupting RAS may be beneficial for patients with ED.

Conclusions

Studies have demonstrated that RAS is crucial in erectile function. Better understanding of the signaling pathways mediating Ang II physiologic actions will provide important information for the treatment of ED.
TNF-α Infusion Impairs Corpora Cavernosa Reactivity
Authors: Carneiro Fernando S. , Zemse Saiprazad , Giachini Fernanda R.C. , Carneiro Zidonia N. , Lima Victor V. , Webb R. Clinton , Tostes Rita C.
Published: February 2009

Introduction

Erectile dysfunction (ED), as well as cardiovascular diseases (CVDs), is associated with endothelial dysfunction and increased levels of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α).

Aim

We hypothesized that increased TNF-α levels impair cavernosal function.

Methods

In vitro organ bath studies were used to measure cavernosal reactivity in mice infused with vehicle or TNF-α (220 ng/kg/min) for 14 days. Gene expression of nitric oxide synthase isoforms was evaluated by real-time polymerase chain reaction.

Main Outcome Measures

Corpora cavernosa from TNF-α-infused mice exhibited decreased nitric oxide (NO)-dependent relaxation, which was associated with decreased endothelial nitric oxide synthase (eNOS) and neuronal nitric oxide synthase (nNOS) cavernosal expression.

Results

Cavernosal strips from the TNF-α-infused mice displayed decreased nonadrenergic–noncholinergic (NANC)-induced relaxation (59.4 ± 6.2 vs. control: 76.2 ± 4.7; 16 Hz) compared with the control animals. These responses were associated with decreased gene expression of eNOS and nNOS (P < 0.05). Sympathetic-mediated, as well as phenylephrine (PE)-induced, contractile responses (PE-induced contraction; 1.32 ± 0.06 vs. control: 0.9 ± 0.09, mN) were increased in cavernosal strips from TNF-α-infused mice. Additionally, infusion of TNF-α increased cavernosal responses to endothelin-1 and endothelin receptor A subtype (ETA) receptor expression (P < 0.05) and slightly decreased tumor necrosis factor-alpha receptor 1 (TNFR1) expression (P = 0.063).

Conclusion

Corpora cavernosa from TNF-α-infused mice display increased contractile responses and decreased NANC nerve-mediated relaxation associated with decreased eNOS and nNOS gene expression. These changes may trigger ED and indicate that TNF-α plays a detrimental role in erectile function. Blockade of TNF-α actions may represent an alternative therapeutic approach for ED, especially in pathologic conditions associated with increased levels of this cytokine.
A New Strategy, SuperEnzyme Gene Therapy in Penile Rehabilitation
Authors: Yuan Jiuhong , Westney O. Lenaine , Ruan Ke-He , Wang Run
Published: February 2009

Introduction

Erectile dysfunction (ED) after radical prostatectomy (RP) is a very common condition. Prostacyclin (PGI2) is a prostaglandin with properties of vasodilation and anti-platelet aggregation. SuperEnzyme is a newly engineered protein with PGI2 synthase activity that converts arachidonic acid directly to PGI2. Transfection of SuperEnzyme into the penis to generate high levels of PGI2 may increase penile blood inflow, alleviate hypoxia, and prevent apoptosis and fibrosis with potential use for ED after RP.

Aim

The pathophysiology of ED after RP and the prostaglandin regulation was reviewed, and the possibly relevant mechanism of SuperEnzyme as a therapy for ED after RP was proposed.

Main Outcome Measure

The rationale for SuperEnzyme as a possible therapy for ED after RP is analyzed.

Methods

We reviewed the publications on the proposed pathophysiology of ED after RP, the molecular regulation of prostaglandin and methods of SuperEnzyme engineering and transfection.

Results

ED after RP is involved in hypoxia, apoptosis and fibrosis, mainly due to the cavernosal nerve injury. Transfection of SuperEnzyme into the penis of an animal model to produce PGI2 is feasible. Animal studies with the use of SuperEnzyme gene therapy are needed to provide new insight into metabolic and signaling pathways of PGI2 in the penis and the role of PGI2 signaling in the recovery of erectile function after RP.

Conclusion

SuperEnzyme may be a potential candidate as a gene therapy for ED after RP.
Gemcitabine‐induced radiation recall in the treatment of pancreatic cancer
Authors: WAN ZAINON Wan Mohd Nazri , BORG M , HIGGS B , YEOH E , KOTASEK D , PARNIS F , HILLENBAND E , HAMZAH S
Published: February 2009

Aim:  To evaluate two cases of gemcitabine‐induced radiation recall in patients who were treated for localized pancreatic cancer, and review the literature.

Methods:  The two cases of radiation recall (from a cohort of 80 patients treated for pancreatic carcinoma) were retrospectively identified using patient medical records. Prior publications were identified through an English language literature search of MEDLINE Ovid from January 1966 to October 2006, using the key words gemcitabine and radiation recall.

Results:  Both the radiation recall reactions were limited to the gastrointestinal system, localized to previous radiotherapy field. No pathology was identified on radiological investigation. The onset of the radiation recall phenomenon was 2 and 10 days, respectively, from the time gemcitabine was initiated. The treatment of radiation recall consisted of the cessation of gemcitabine, initiating steroid therapy and supportive therapy. Both of the patients' symptoms achieved complete resolution. A comprehensive review of the literature found 15 previous cases of radiation recall related to gemcitabine but one reported effect involving the gastrointestinal system. Previously reported sites of recall phenomena included the skin, muscles, brain stem and optic nerve. In the treatment of pancreatic carcinomas, there were only four reported cases, three involving the onset of myositis of abdominal muscle and one case of gastrointestinal bleeding.

Conclusion:  Radiation recall from gemcitabine chemotherapy is uncommon. It can potentially arise in any site that has been irradiated previously. The treating doctor needs to be aware of this phenomenon to be able to manage this condition appropriately.
Acute leukemia: Diagnosis improved by flow cytometry in addition to morphology
Authors: SENGAR Manju , RAI Ambak K , SAXENA Ankit , SINGH Amar , RAINA Vinod , SETH Tulika , SHARMA Atul , BAKHSI Sameer , KUMAR Rajive , MITRA Dipendra K
Published: February 2009

Aims:  Immunophenotyping using flow cytometry (FCM) has become an essential component of acute leukemia (AL) diagnosis. This study evaluated the judicious application of FCM as an adjunct to well‐informed morpho‐cytochemical assessment in patients with acute leukemia.

Methods:  100 untreated patients with AL were studied using morpho‐cytochemistry and immunophenotyping through FCM.

Results:  There were 29 patients with acute myeloid leukemia (AML), 47 with B‐acute lymphoblastic leukemia (ALL), 20 with T‐acute lymphoblastic leukemia (ALL) and four with biphenotypic acute leukemia (BAL). Morpho‐cytochemistry without FCM could provide definite diagnosis only in the AML cases. It failed to provide definite diagnosis in ALL patients. Over half (55%) of ALL patients were given the noncommittal label, AL. The remaining 45% patients were labeled a more definite, probable ALL.

Conclusion:  FCM thus had a role to play in ALL patients to confirm a definite and a probable diagnosis, to define therapeutically and prognostically groups such as B and T lineage ALL and to distinguish AML – M0 from ALL. FCM helps in diagnosing AML cases as well, but is a less essential mode of investigation in this group purely from the perspective of the therapy regime. But its role in defining different subgroups in AML is its major use. While morpho‐cytochemistry provides a first‐line investigation of great therapeutic value, and more so in AML, it needs to be supplemented by flow cytometry, particularly in ALL.
Phase II study of gemcitabine and docetaxel in combination for the treatment of metastatic breast cancer
Authors: GOEL Shom , ABDI Ehtesham , LEWIS Craig R , LINKS Matthew , BEGBIE Steven , CLINGAN Philip , GANJU Vinod , BEITH Jane
Published: February 2009

Aim:  Gemcitabine (G) and docetaxel (D) have both shown activity in the treatment of anthracycline‐pretreated patients with metastatic breast cancer. This phase II study was designed to evaluate the safety and efficacy of the GD combination.

Methods:  Patients with measurable locally advanced or metastatic breast cancer who had previously received anthracycline‐based therapy were eligible. The patients received D 40 mg/m2 followed by G 800 mg/m2 IV on days 1 and 8 every 3 weeks for a maximum of eight cycles.

Results:  Thirty patients were enrolled and received a median of five cycles (range 0–8). Of these, 24 were evaluable for efficacy, with an overall response rate of 29.2% (95% CI, 12.6–51.1%). An additional 36.7% had a stable disease for an overall clinical benefit of 65.9%. The median duration of response was 2.1 months (95% CI, 2.0–3.6 months) and the median time to disease progression was 5.5 months (95% CI, 2.0–8.9 months). The median survival time was 16.7 months (95% CI, 7.3–32.0 months). Myelosuppression was the major toxicity, with grade 3/4 neutropenia in 73.3% of patients and febrile neutropenia in 6.7%.

Conclusion:  Weekly G and D is an active and safe regimen in treating metastatic breast cancer. The response rate was lower than that previously reported for this combination, which may relate to the lower doses used and the weekly D schedule. It may be worthwhile to further explore this combination to determine the optimal dosing schedule.
Randomized phase II trial of gemcitabine and either day 1 or day 8 carboplatin for advanced non‐small‐cell lung cancer: Is thrombocytopenia predictable?
Authors: CROMBIE Cathy , BURNS W Ivon , KARAPETIS Christos , LOWENTHAL Ray M , KIRSTEN Fred , DAVIDSON J Andrew , ABELL Fiona , REECE William HH , IGLESIAS Jose , DE SOUZA Paul
Published: February 2009

Aim:  Two 21‐day gemcitabine–carboplatin schedules were evaluated in patients with advanced non‐small cell lung cancer in order to assess the effect of timing of the carboplatin dose on toxicity and efficacy.

Methods:  Patients were randomized to gemcitabine (1000 mg/m2 on days 1 and 8 of a 21‐day cycle) and carboplatin (AUC 5, on day 1) (Carbo d1 arm) or the same gemcitabine schedule with carboplatin given on day 8 (Carbo d8 arm). Twenty patients with Stage IIIB or IV non‐small‐cell lung cancer were enrolled in each arm.

Results:  The achieved dose intensities of both gemcitabine and carboplatin were significantly higher in the Carbo d1 arm. The total rates of grade 3 or 4 hematological and non‐hematological toxicities (any toxicity, any cycle) were 80% and 65%, respectively, with no significant differences between the two arms. Nine patients in the Carbo d1 arm, but only one patient in the Carbo d8 arm, required a platelet transfusion. There were 10 partial responses (four Carbo d1 arm, six Carbo d8 arm), giving an overall response rate of 25% (95% CI 13–41%).

Conclusion:  Administration of carboplatin on day 8 of this regimen confers no clear advantage compared with day 1 carboplatin, with similar toxicity but lower dose intensity. A formula for the prediction of thrombocytopenia is proposed.