bluuebunny/crossref_metadata_2025 huggingface dataset:
Oestrogen stimulates endothelial progenitor cells via oestrogen receptor‐α
Authors: Foresta Carlo , Zuccarello Daniela , Biagioli Andrea , De Toni Luca , Prana Elisa , Nicoletti Valentina , Ambrosini Guido , Ferlin Alberto
Published: June 2007

Context  Oestrogens play an important protective role on the vascular system. The endothelial cell layer is a direct target for these hormones, and expresses at least two oestrogen receptors, ER‐α and ER‐β. Recent studies have shown that vascular healing is significantly modulated by circulating bone marrow‐derived cells. A subset of these stem cells, endothelial progenitor cells (EPCs), have recently been described as a population of pluripotent cells within the peripheral blood capable of differentiating into endothelial cells.

Objective  In the present study we investigated the expression of ER‐α and ER‐β on human EPCs and the effect that oestrogens have on the function of EPCs in vitro.

Methods  EPCs were isolated and cultured from healthy donors. RT‐PCR, western blotting and immunohistochemistry were used to assess expression of ER‐α and ER‐β. Proliferation and CFU assays were used to assess the response of EPCs to different doses of 17,β‐oestradiol.

Main outcome measures  Expression of ER‐α and ER‐β in EPCs, and the effect of 17,β‐oestradiol on proliferation of EPCs.

Results  Human EPCs express ER‐α mRNA and protein. 17,β‐oestradiol increases proliferation of EPCs and CFU in a dose‐dependent manner.

Conclusions  Human EPCs express ER‐α but not ER‐β, and oestrogens can stimulate the proliferation of these cells in vitro. Oestrogens exert these effects at concentrations that are usually reached during stimulation for in vitro fertilization in women, and therefore further studies are needed to clarify the clinical significance of these effects.
Mutations in GCK and HNF‐1α explain the majority of cases with clinical diagnosis of MODY in Spain
Authors: Estalella Itziar , Rica Itxaso , De Nanclares Guiomar Perez , Bilbao Jose Ramon , Vazquez Jose Antonio , San Pedro Jose Ignacio , Busturia Maria Angeles , Castaño Luis ,   Spanish MODY Group
Published: June 2007

Objective  The aim of this study was to group patients with MODY (maturity‐onset diabetes of the young) according to the genetic alterations underlying the disease and to investigate their clinical characteristics.

Patients and methods  Molecular analysis of GCK (MODY2), HNF‐1α (MODY3), HNF‐4α (MODY1) and HNF‐1β (MODY5) genes was performed by DNA sequencing in 95 unrelated index probands (47M/48F; mean age 9·9 ± 5·2 years) with clinical diagnosis of MODY. After classification into MODY subtypes according to the genetic alterations, clinical characteristics were compared between the groups.

Results  Seventy‐six families were shown to carry mutations in GCK (34 of them previously unreported), eight families presented HNF‐1α mutations, and a large genomic rearrangement in HNF‐1β was found in a family. No alteration was found in HNF‐4α. Thus, relative frequencies in the group studied were 80% MODY2, 8·5% MODY3 and 1% MODY5. Comparison of clinical parameters according to genetic status showed significant differences between MODY2 and MODY3 patients in age at diagnosis (9·4 ± 5·4 years vs. 12·7 ± 4·6 years), diagnosis (impaired glucose tolerance vs. diabetes), diagnostic test used (OGTT vs. fasting glucose), treatment (diet and exercise vs. insulin/oral antidiabetic agents) and birth weight (2·96 ± 0·44 kg vs. 3·40 ± 0·67 kg).

Conclusion  Almost 90% of the MODY cases in the group studied are explained by mutations in the major genes GCK (MODY2) and HNF‐1α(MODY3), although differences in the relative prevalence of each form could be partly due to patient referral bias (paediatric vs. adult). In general, patients with MODY2 were diagnosed at an earlier age in life than MODY3 patients and had a milder form of diabetes. Moreover, the majority of patients with MODY2 mutations were treated with diet whereas half of MODY3 patients received pharmacological treatment.
A clinical trial on absorption andN‐acetylation of oral and rectal mesalazine
Authors: Dilger K. , Trenk D. , Rössle M. , Cap M. , Zähringer A. , Wacheck V. , Remmler C. , Cascorbi I. , Kreisel W. , Novacek G.
Published: June 2007

Background Mesalazine (5‐ASA) is a standard treatment for ulcerative colitis. Extent of absorption andN‐acetylation determine systemic exposure to 5‐ASA, and are thereby relevant for the safety of the treatment. The aim of the study was to compare absorption andN‐acetylation of 5‐ASA following rectal or oral drug administration. Healthy subjects were compared to patients with ulcerative colitis to evaluate the impact of chronic inflammation of colorectal mucosa on disposition of 5‐ASA.

Materials and methods First, 12 healthy adults were randomized to receive 2 g of 5‐ASA by each of four different formulations: oral delayed release granules, 30 mL enema, 60 mL rectal foam, and 120 mL rectal foam. Second, 12 patients with active ulcerative colitis received 60 mL rectal foam. Pharmacokinetic analysis was performed by determination of 5‐ASA and its acetylated, pharmacologically inactive metabolite (Ac‐5‐ASA) in plasma and urine.

Results First, systemic exposure to 5‐ASA was markedly lower after rectal drug administration as compared to oral dosing (P < 0·001; e.g. median relative bioavailability of 60 mL rectal foam: 36%). Second,N‐acetylation of rectal 5‐ASA was lower in patients than in healthy subjects [area under the curve (AUC) ratio Ac‐5‐ASA/5‐ASA: 1·6 ± 0·5 vs. 2·3 ± 0·4, mean ± SD,P < 0·01]. High peak plasma concentrations of 5‐ASA were correlated with high microscopic disease activity (r = 0·67,P < 0·05).

Conclusions Rectal delivery of 5‐ASA results in low systemic drug exposure with potentially reduced toxicity in comparison with oral drug administration. Chronic inflammation of colorectal mucosa might be a relevant source of variability in pharmacokinetics of 5‐ASA.
Lifestyle intervention in individuals with normal versus impaired glucose tolerance
Authors: Schäfer S. , Kantartzis K. , Machann J. , Venter C. , Niess A. , Schick F. , Machicao F. , Häring H.‐U. , Fritsche A. , Stefan N.
Published: June 2007

Background  Lifestyle intervention is effective in the prevention of type 2 diabetes in individuals with impaired glucose tolerance (IGT). It is currently unknown whether it has beneficial effects on metabolism to a similar extent, in individuals with normal glucose tolerance (NGT) compared to individuals with IGT.

Materials and methods  Data from 181 subjects (133 with NGT and at risk for type 2 diabetes and 48 with IGT) who participated in the Tuebingen Lifestyle Intervention Program with increase in physical activity and decrease in caloric intake were included into this study. Body fat distribution was quantified by whole‐body magnetic resonance (MR) tomography and liver fat and intramyocellular fat by 1H‐MR spectroscopy. Insulin sensitivity was estimated from an oral glucose tolerance test (OGTT).

Results  After 9 ± 2 months of follow‐up, the diagnosis of IGT was reversed in 24 out of 48 individuals. Only 14 out of 133 participants with NGT developed IGT. Body weight decreased in both groups by 3% (both P < 0·0001). Two‐hour glucose concentrations during an OGTT decreased in individuals with IGT (–14%, P < 0·0001) but not with NGT (+2%, P = 0·66). Insulin sensitivity increased both in individuals with IGT (+9%, P = 0·04) and NGT (+17%, P < 0·0001). Visceral fat (–8%, P = 0·006), liver fat (–28%, P < 0·0001) and intramyocellular fat (–15%, P = 0·006) decreased in participants with IGT. In participants with NGT these changes were significant for visceral fat (–16%, P < 0·0001) and liver fat (–35%, P < 0·0001).

Conclusions  Moderate weight loss under a lifestyle intervention with reduction in total, visceral and ectopic fat and increase in insulin sensitivity improves glucose tolerance in individuals with IGT but not with NGT. In individuals with NGT, the beneficial effects of a lifestyle intervention on fat distribution and insulin sensitivity possibly prevent future deterioration in glucose tolerance.
Placental immaturity and hyperinsulinaemia in full‐term newborns
Authors: Rodríguez‐Morán M. , Levario‐Carrillo M. , González J. L. , Sánchez‐Ramírez B. , Martínez‐Aguilar G. , Guerrero‐Romero F.
Published: June 2007

Background  Evidence from large studies suggests that low birthweight is a risk factor for cardiovascular disease and glucose metabolism disorders in adulthood, but the physiological mechanisms involved in intrauterine growth conditioning low birthweight are not completely understood. The objectives of this study were to determine whether placental immaturity (PI), defined as the lower quartile of placental maturity index (PMI), is associated to hyperinsulinaemia at birth and to identify the risk factors associated with PI.

Materials and methods  Cross‐sectional study conducted at medical research units of two Mexican general hospitals. A total of 272 full‐term newborns with gestational age ≥ 38 and < 41 weeks were allocated into the corresponding group according to the quartile distribution of PMI. Data from the lower (PMI < 13·3) and higher quartile (PMI ≥ 24·3) were compared. The PMI was estimated by dividing the number of epithelial plates by the average thickness of the epithelial plate. Serum measures included cord glucose and insulin levels of the newborns at birth.

Results  A total of 74 (27·2%) children had hyperinsulinaemia at birth, of them 47 (63·5%) with PI. The adjusted multiple regression analysis showed a strong association between PI and hyperinsulinaemia at birth [odds ratio (OR) 2·6; CI 95% 1·3–4·3). Additional adjusted analysis showed that both mother's age ≤ 16 years (OR 1·75; CI95% 1·2–9·1) and maternal cigarette smoking (OR 2·7; CI95% 1·3–8·9) are associated to PI.

Conclusions  The PI is independently associated with hyperinsulinaemia at birth: smoking and mother's age lower than 16 years are risk factors for development of PI.
Novel SDHD germ‐line mutations in pheochromocytoma patients
Authors: Neumayer C. , Moritz A. , Asari R. , Weinhäusel A. , Hölzenbein T. , Kretschmer G. , Niederle B. , Haas O. A.
Published: June 2007

Background  SDHD germ‐line mutations predispose to pheochromocytoma (PCC) and paraganglioma (PGL).

Material and methods  The incidence and types of SDHD germ‐line mutations are determined in 70 patients with apparently sporadic adrenal and extra‐adrenal PCC.

Results  SDHD sequence variants were identified in the germ line of five patients. Two of three novel mutations were in exon 1 and one in exon 3. One patient had a codon 1 missense mutation (M1K) and a concurrent 3‐bp deletion in intron 1. Three of 10 family members had only the exon 1 mutation, whereas one had only the intron 1 mutation. The other exon 1 mutation resulted from a deletion of nucleotides 28–33 with a 12‐bp in‐frame insertion (c.28_33 del ins TAGGAGGCCCTA). This mutation generated a premature stop codon after codon 9 and was also present in the brother who had a bilateral PCC. The third patient with a carotid body tumour, with an abdominal and a thoracic PGL had a 12‐bp deletion in exon 3 (codons 91–94, c.271_282 del). Her father carried the same mutation and had bilateral carotid body tumours. Two further patients, one with six PGL, carried a previously described H50R polymorphism, whose disease‐specific relevance is currently unclear. The three patients with bona fide SDHD mutations were younger than those without germ‐line mutations.

Conclusion  SDHD germ‐line mutations are rare in patients with PCC, but their identification is an important prerequisite for the clinical care and appropriate management of affected individuals and their families.
Patients with macroprolactinaemia: clinical and radiological features
Authors: Donadio F. , Barbieri A. , Angioni R. , Mantovani G. , Beck‐Peccoz P. , Spada A. , Lania A. G.
Published: June 2007

Background  Macroprolactinaemia may represent a relevant cause of misdiagnosis, unnecessary investigation and inappropriate treatment. The aim of this study was to investigate the clinical and neuroradiological characteristics of patients with and without macroprolactinaemia and to evaluate the impact of macroprolactin determination on the diagnostic work‐up of hyperprolactinaemic patients.

Materials and methods  Retrospective analysis in 135 consecutive hyperprolactinaemic patients (111 women and 24 men; mean age 37 ± 11·6 years) whose archived sera were subsequently tested for macroprolactin. Recoveries ≤ 40% after polyethylene glycol precipitation were indicative of macroprolactinaemia.

Results  Macroprolactin, entirely explaining biochemical hyperprolactinaemia, was found in 42·2% of patients, a third of whom presented with signs and symptoms of hyperprolactinaemia. Determination of macroprolactin changed the initial diagnosis in a consistent proportion of patients. In particular, idiopathic hyperprolactinaemia, initially diagnosed in 41 patients, was then excluded in 28 of them. Diagnosis of prolactin‐secreting pituitary microadenoma shifted to non‐secreting pituitary microadenoma in 10 of 49 patients, while in all patients with prolactin‐secreting pituitary macroadenoma or hyperprolactinaemia due to stalk deafferentation the presence of macroprolactin was excluded and the initial diagnosis confirmed. Finally, macroprolactin was present in the majority of patients with magnetic resonance imaging (MRI) scans suggestive for primary empty sella (4 of 5 women) or pituitary hyperplasia (12 of 17 women, 3 of 3 men). Collectively, about half of subjects with macroprolactinaemia showed variable MRI abnormalities.

Conclusions  The presence of macroprolactin was a relevant cause of misdiagnosis in patients with hyperprolactinaemia. However, due to the unexpected high frequency of pituitary abnormalities observed in the present series, we suggest that the diagnostic algorithm of hyperprolactinaemic states should include both polyethylene glycol precipitation test and MRI imaging.
Complexity of the HVR‐1 quasispecies and disease activity in patients with hepatitis C
Authors: Kumagai N. , Kaneko F. , Tsunematsu S. , Tsuchimoto K. , Tada S. , Saito H. , Hibi T.
Published: June 2007

Background  Hepatitis C virus (HCV) easily undergoes genomic changes, especially in the hypervariable region (HVR) in the N‐terminus of the E2/NS1 region. The quasispecies nature of HCV may have important biological implications in relation to viral persistence; however, the relationship between disease activity of chronic HCV infection and development of the genomic complexity have yielded conflicting results. We explored the changes in the complexity of the HVR‐1 in the natural course of chronic HCV infection with and without elevation of serum alanine transaminase (ALT) levels.

Materials and methods  Ten patients with chronic hepatitis C proven by liver biopsy, who showed persistent elevation of the serum ALT levels, and 15 patients with chronic HCV infection and persistently normal serum ALT levels (PNAL) were enrolled in this study. The number of the HCV quasispecies was determined twice for each patient at an interval of mean 2·5 years by fluorescence single‐strand conformation polymorphism and sequence analysis.

Results  There was no significant difference in the changes in the number of quasispecies during the follow‐up period between chronic hepatitis C and PNAL. There was also no significant difference in the change in the number of variable nucleotides sites between the two groups. In these patients, the number of quasispecies and the diversity of HVR‐1 were correlated with platelet counts and serum hyaluronic acid levels previously shown to be associated with disease progression.

Conclusion  Our results suggested that the disease activity is not always related to the generation of the HVR‐1 quasispecies complexity.
The 15N‐CPMAS spectra of simazine and its metabolites: measurements and quantum chemical calculations
Authors: Berns A. E. , Bertmer M. , Schäffer A. , Meier R. J. , Vereecken H. , Lewandowski H.
Published: June 2007

DFT calculations are a powerful tool to support NMR studies of xenobiotics such as decomposition studies in soil. They can help interpret spectra of bound residues, for example, by predicting shifts for possible model bonds. The described bound‐residue models supported the hypothesis of a free amino side chain already suspected by comparison with the experimental data of the standards. No match was found between the calculated shifts of amide bondings of the amino side chains (free or substituted) and the experimental NMR shifts of a previous study. In the present paper, first‐principles quantum chemical calculations were used to support and check the interpretation of the 15N cross polarization‐magic angle spinning nuclear magnetic resonance (15N‐CPMAS NMR) spectra of simazine and its metabolites. Density functional theory (DFT) calculations were performed using Gaussian 03 and the nuclear magnetic shielding tensors were calculated using the Gauge‐Independent Atomic Orbital (GIAO) method and B3LYP/6–311+G(2d,p) model chemistry. Good agreement was reached between the calculated and measured chemical shifts of the core nitrogens and the lactam and lactim forms of the hydroxylated metabolites could be clearly distinguished. The calculated spectra showed that these metabolites exist preferentially in the lactam form, an important fact when considering the possible interactions of such hydroxylated metabolites with the soil matrix. Although the calculated bound‐residue models in the present study only partly matched the experimental data, they were nevertheless useful in helping to interpret the experimental NMR results of a previous study. To get a better match between the calculated and the measured shifts of the side‐chain nitrogens the calculations need to be further developed, taking into account the influence of neighbouring molecules in the solid state. Altogether, quantum chemical calculations are very helpful in the interpretation of NMR spectra. In the future, they can also be very useful for the prediction of NMR shifts, in particular when it is not possible to measure the metabolites due to a lack of material or in cases where practical experiments cannot be conducted.
Changes in nitrogen cycling and retention processes in soils under spruce forests along a nitrogen enrichment gradient in Germany
Authors: CORRE MARIFE D. , BRUMME RAINER , VELDKAMP EDZO , BEESE FRIEDRICH O.
Published: June 2007

A network of long‐term monitoring sites on nitrogen (N) input and output of forests across Germany showed that a number of Germany's forests are subject to or are experiencing N saturation and that spruce (Picea abies) stands have high risk. Our study was aimed at (1) quantifying the changes in gross rates of microbial N cycling and retention processes in forest soils along an N enrichment gradient and (2) relating the changes in soil N dynamics to N losses. We selected spruce sites representing an N enrichment gradient (indicated by leaching : throughfall N ratios) ranging from 0.04–0.13 (low N),≤0.26 (intermediate N enrichment) to≥0.42 (highly N enriched). To our knowledge, our study is the first to report on mechanistic changes in gross rates of soil N cycling and abiotic NO3− retention under ambient N enrichment gradient. Gross N mineralization, NH4+ immobilization, gross nitrification, and NO3− immobilization rates increased up to intermediate N enrichment level and somewhat decreased at highly N‐enriched condition. The turnover rates of NH4+ and microbial N pools increased while the turnover rates of the NO3− pool decreased across the N enrichment gradient. Abiotic immobilization of NH4+ did not differ across sites and was lower than that of NO3−. Abiotic NO3− immobilization decreased across the N enrichment gradient. Microbial assimilation and turnover appeared to contribute largely to the retention of NH4+. The increasing NO3− deposition and decreasing turnover rates of the NO3− pool, combined with decreasing abiotic NO3− retention, possibly contributed to increasing NO3− leaching and gaseous emissions across the N enrichment gradient. The empirical relationships of changes in microbial N cycling across the N enrichment gradient may be integrated in models used to predict responses of forest ecosystems (e.g. spruce) to increasing N deposition.
Taxonomic and biological trait differences of stream macroinvertebrate communities between mediterranean and temperate regions: implications for future climatic scenarios
Authors: BONADA NÚRIA , DOLÉDEC SYLVAIN , STATZNER BERNHARD
Published: June 2007

Streams in mediterranean regions have highly seasonal discharge patterns, with predictable torrential floods and severe droughts. In contrast, discharge is less variable in temperate regions and intermittent flow conditions are uncommon. Hydroclimatic models predict that climate change would increase frequency and severity of floods and droughts across Europe, thus increasing the proportion of streams with mediterranean characteristics in actually temperate areas. Correspondingly, understanding actual ecological differences between mediterranean and temperate streams may help to anticipate large‐scale ecological impacts of climate change. Given that large‐scale factors determine local community composition, we hypothesized that climatic differences between mediterranean and temperate regions should affect the taxonomic and biological trait composition in streams. We assembled the abundance of stream macroinvertebrate genera of 265 sites each from the Mediterranean Basin and from temperate Europe and linked these abundances to published information on 61 categories of 11 biological traits reflecting the potential of resilience from and resistance to disturbances. Although regional taxonomic richness was higher in the mediterranean than in the temperate region, local taxonomic richness and diversity did not significantly differ between regions. Local trait richness and diversity were significantly higher in the mediterranean region. Both local taxonomic and trait‐community composition differed between regions, but the former varied much more than the latter, highlighting that climate change could produce large changes in the taxonomic but rather weak changes in the trait composition. The mediterranean region was characterized by macroinvertebrates with higher dispersion and colonization capabilities, suggesting that species loss in the temperate region, by extinction or northward emigration of taxa, would be compensated for by immigration of southern mediterranean taxa. Thus, climate change would likely have stronger implications for the local conservation of taxa than for the trait composition of stream macroinvertebrate communities.
Genetic maladaptation of coastal Douglas‐fir seedlings to future climates
Authors: BRADLEY ST CLAIR J. , HOWE GLENN T.
Published: June 2007

Climates are expected to warm considerably over the next century, resulting in expectations that plant populations will not be adapted to future climates. We estimated the risk of maladaptation of current populations of coastal Douglas‐fir (Pseudotsuga menziesiivar.menziesii) to future climates as the proportion of nonoverlap between two normal distributions where the means and genetic variances of current and future populations are determined from genecological models derived from seedling common garden studies. The risk of maladaptation was large for most traits when compared with the risk associated with current transfers within seed zones, particularly for the more drastic climate change scenario. For example, the proportion of nonoverlap for a composite trait representing bud set, emergence, growth, and root : shoot ratio was as high as 0.90. We recommend augmenting within‐population variation by mixing local populations with some proportion of populations from lower elevations and further south. Populations expected to be adapted to climates a century from now come from locations as far down in elevation as 450–1130 m and as far south in latitude as 1.8–4.9°.
Potential effects of interaction between CO2and temperature on forest landscape response to global warming
Authors: XU CHONGGANG , GERTNER GEORGE Z. , SCHELLER ROBERT M.
Published: June 2007

Projected temperature increases under global warming could benefit southern tree species by providing them the optimal growing temperature and could be detrimental to northern species by exposing them to the supra optimal growing temperatures. This benefit‐detriment trade‐off could increase the competitive advantage of southern species in the northern species range and cause the increase or even dominance of southern species in the northern domain. However, the optimum temperature for photosynthesis of C3 plants may increase due to CO2enrichment. An increase in the optimum temperature could greatly reduce the benefit‐detriment effect. In this study, we coupled a forest ecosystem process model (PnET‐II) and a forest GAP model (LINKAGES) with a spatially dynamic forest landscape model (LANDIS‐II) to study how an optimum temperature increase could affect forest landscape response due to global warming. We simulated 360 years of forest landscape change in the Boundary Water Canoe Area (BWCA) in northern Minnesota, which is transitional between boreal and temperate forest. Our results showed that, under the control scenario of continuing the historic 1984–1993 mean climate (mainly temperature, precipitation and CO2), the BWCA will become a spruce‐fir dominated boreal forest. However, under the scenario of predicted climatic change [the 2000–2099 climates are predicted by Canadian Climate Center (CCC), followed by 200 years of continuing the predicted 2090–2099 mean climate], the BWCA will become a pine‐dominated mixed forest. If the optimum temperature increases gradually with [CO2] (the increase in optimum temperature is assumed to change gradually from 0 °C in year 2000 to 5 °C in year 2099 when [CO2] reaches 711 ppm and stabilizes at 5 °C after year 2099), the BWCA would remain a fir‐dominated boreal forest in areas with relatively high water‐holding capacity, but not in areas with relatively low water‐holding capacity. Our results suggest that the [CO2] induced increases in optimum temperature could substantially reduce forest landscape change caused by global warming. However, not all tree species would be able to successfully adapt to future warming as predicted by CCC, regardless of optimum temperature acclimations.
Nitrite‐driven nitrous oxide production under aerobic soil conditions: kinetics and biochemical controls
Authors: VENTEREA RODNEY T.
Published: June 2007

Nitrite (NO2−) can accumulate during nitrification in soil following fertilizer application. While the role of NO2− as a substrate regulating nitrous oxide (N2O) production is recognized, kinetic data are not available that allow for estimating N2O production or soil‐to‐atmosphere fluxes as a function of NO2− levels under aerobic conditions. The current study investigated these kinetics as influenced by soil physical and biochemical factors in soils from cultivated and uncultivated fields in Minnesota, USA. A linear response of N2O production rate () to NO2− was observed at concentrations below 60 μg N g−1 soil in both nonsterile and sterilized soils. Rate coefficients (Kp) relating to NO2− varied over two orders of magnitude and were correlated with pH, total nitrogen, and soluble and total carbon (C). Total C explained 84% of the variance in Kp across all samples. Abiotic processes accounted for 31–75% of total N2O production. Biological reduction of NO2− was enhanced as oxygen (O2) levels were decreased from above ambient to 5%, consistent with nitrifier denitrification. In contrast, nitrate (NO3−)‐reduction, and the reduction of N2O itself, were only stimulated at O2 levels below 5%. Greater temperature sensitivity was observed for biological compared with chemical N2O production. Steady‐state model simulations predict that NO2− levels often found after fertilizer applications have the potential to generate substantial N2O fluxes even at ambient O2. This potential derives in part from the production of N2O under conditions not favorable for N2O reduction, in contrast to N2O generated from NO3− reduction. These results have implications with regard to improved management to minimize agricultural N2O emissions and improved emissions assessments.
Primary and recurrent embryonal sarcoma of the liver: clinicopathological and immunohistochemical analysis
Authors: Zheng J‐M , Tao X , Xu A‐M , Chen X‐F , Wu M‐C , Zhang S‐H
Published: June 2007

Aims:  To evaluate primary and recurrent embryonal sarcoma of the liver and to improve recognition of its morphological variants and immunohistochemical features.

Methods and results:  Fourteen primary and two recurrent cases of hepatic embryonal sarcoma were evaluated histologically and investigated immunohistochemically with a panel of antibodies using the EnVision+ system. They were usually single, large, globular masses with solid and cystic gelatinous areas. Microscopic features included spindle, oval, stellate, epithelioid or multinucleated cells loosely or densely arranged in a myxomatous matrix. Entrapped bile ducts and hepatic cords were often present at the periphery of the tumours. Intracellular and extracellular periodic acid–Schiff‐positive, diastase‐resistant hyaline globules were commonly present. Recurrent tumours showed greater cellularity, anaplasia and pluripotential differentiation compared with the primary tumour. Immunohistochemistry showed evidence of widely divergent differentiation into mesenchymal and epithelial phenotypes.

Conclusions:  Embryonal sarcoma of the liver may undergo pluripotential differentiation and diagnosis should be based mainly on morphological features. Immunohistochemistry has no specific or diagnostic relevance, but, by using a panel of antibodies, may help to exclude other tumours.
Occurrence of oxidative impairments, response of antioxidant defences and associated biochemical perturbations in male reproductive milieu in the Streptozotocin‐diabetic rat
Authors: Shrilatha B. , Muralidhara
Published: June 2007

Oxidative stress is implicated to play a vital role in the pathogenesis of various diabetic complications. While reproductive dysfunction is a well recognized consequence of diabetes mellitus, the underlying mechanisms are poorly understood. The present study aims to obtain insights into the incidence, extent and progression of oxidative impairments in testis and epididymal sperm (ES) in streptozotocin (STZ)‐induced diabetic rat during early and progressive phase. Adult rats (CFT‐Wistar strain) rendered diabetic by an acute dose of STZ (60 mg/kg bw, i.p.) were examined for induction of hyperglycaemia at 72 h, followed by the assessment of oxidative impairments in testis and ES over a 6‐week period. Oxidative damage was ascertained by measuring the malondialdehyde levels, reactive oxygen species (ROS) generation, alterations in antioxidant defences and extent of protein oxidation. STZ induced a significant (2.5‐fold) increase in blood glucose levels. In diabetic rats, both testis and ES showed enhanced status of lipid peroxidation measured as increased TBARS and ROS from week 2 onwards. These impairments in testis were consistent, progressive and accompanied by marked alterations in antioxidant defences and elevated protein carbonyls. Varying degree of reduction in the specific activities of antioxidant enzymes was evident in testis and ES, while the activity of glutathione‐S‐transferase (GST) was significantly elevated. Reduced glutathione (GSH) and vitamin E levels were consistently reduced in testis. Lipid dysmetabolism measured in terms of increased cholesterol, triglycerides and phospholipids was evident only beyond week 2 in diabetic testis. Taken together, these results indicate that the testis and ES are indeed subjected to significant oxidative stress in the STZ‐diabetic rat both during early as well as progressive phase. It is hypothesized that oxidative impairments in testis which develop over time may at least in part contribute towards the development of testicular dysfunction eventually leading to testicular degeneration which culminates in reduced fertility during the progressive phase of STZ‐induced diabetes in adult rats.
Relevance of microRNAs in normal and malignant development, including human testicular germ cell tumours
Authors: Looijenga L. H. J. , Gillis A. J. M. , Stoop H. , Hersmus R. , Oosterhuis J. W.
Published: June 2007

The dogma of genome functionality has recently been challenged by identification of non‐protein‐encoding RNAs, including mi(cro)RNAs. These relatively small sequences interact with mRNA and in the mammalian system, are involved in fine‐tuning the process of translation. miRNAs have been found to be of crucial importance for normal development, including stem cell formation. Recent interesting fundamental observations will be discussed in this paper, as well as their impact on the genesis of human germ cell tumours (GCTs), in particular those of the adult testis, seminomas and non‐seminomas (type II), and spermatocytic seminomas (type III). miRNA cluster 371–373 is specifically involved in inhibition of cellular senescence induced by oncogenic stress in the type II GCTs. This explains the unusual presence of wild type P53, characteristic of this type of solid cancer. Specific sets of differentiating miRNA were found to characterize the various differentiation lineages within the GCTs, which simulate normal embryonic development.
Analysis of gene expression in normal and neoplastic human testis: new roles of RNA
Authors: Novotny G. W. , Nielsen J. E. , Sonne S. B. , Skakkebaek N. E. , Rajpert‐De Meyts E. , Leffers H.
Published: June 2007

Large‐scale methods for analysing gene expression, such as microarrays, have yielded a wealth of information about gene expression at the mRNA level. However, expression of alternative transcripts, together with the presence of a wide range of largely undescribed RNA transcripts combined with regulation from the RNA interference pathway, may cause misinterpretations when trying to base conclusions from expression data derived from studies at the mRNA level. With HLXB9, PRM1, DICER and E2F1 as examples, we here show a range of situations that can occur when investigating gene expression, and give recommendations for the complementary methods that can verify gene expression data from large‐scale studies, as well as give new information regarding the regulation of specific genes. Especially, we show that the absence of a protein despite high expression of the corresponding mRNA can be caused by expression of miRNAs targeting the mRNA. Additionally, we show through cloning the presence of both known and new miRNAs in the testis emphasizing the necessity for following up mRNA expression data by investigating expression at the protein level.
Oxygen uptake by mitochondria in demembranated human spermatozoa: a reliable tool for the evaluation of sperm respiratory efficiency
Authors: Ferramosca A. , Focarelli R. , Piomboni P. , Coppola L. , Zara V.
Published: June 2007

In this work we report a relatively simple and fast method for analysing oxygen consumption and therefore mitochondrial functionality, in individual human ejaculates. This oxygraphic method requires a low number of cells, is highly reproducible and linearly correlates with sperm concentration. Our results have shown that oxygen uptake by mitochondria of demembranated sperm cells from normozoospermic subjects is significantly stimulated by a large set of respiratory substrates and ADP. The respiratory control ratio (RCR) values indicate a good coupling between respiration and phosphorylation by sperm mitochondria and thus a well preserved integrity of the mitochondria themselves. Interestingly, whereas the rates of oxygen uptake, as expected, changed with different sperm concentrations, the RCR values remained constant, thus demonstrating a linear response of the assay. In asthenozoospermic subjects, however, a significant decrease in the sperm respiratory efficiency was found. The results obtained suggest that this method, besides its potential clinical application, could be useful for a deeper understanding of the biochemical properties of sperm mitochondria and their role in ATP production in human spermatozoa.
Testis and prostate cancer incidence in ethnic groups in South East England
Authors: Jack R. H. , Davies E. A. , Møller H.
Published: June 2007

International variations in the incidence of testis and prostate cancer are well established. Data from the USA have also shown differences between White and Black men; however, there has been little work on ethnicity and cancer incidence in the UK, due to incomplete ethnicity information in cancer registries. The Hospital Episode Statistics (HES) dataset has more complete information on self‐assigned ethnicity for inpatients of English NHS hospitals. Data on 194 590 male patients resident in South East England diagnosed with cancer between 1998 and 2003 were extracted from the Thames Cancer Registry (TCR). Of these, ethnicity information from HES was obtained for 123 507 (63%), ethnicity information from TCR was available for a further 5909 (3%), and no ethnicity was available for 65 174 (33%). Compared with ‘All White’ men, testis cancer incidence was significantly lower in Indian, Pakistani, Bangladeshi, Other Asian, Black Caribbean, Black African, Other Black and Chinese men. Prostate cancer incidence was significantly increased in Black Caribbean, Black African, Other Black, Indian, Pakistani, Mixed White and Black Caribbean and Mixed White and Black African groups compared with ‘All White’ men. Bangladeshi and Chinese men had a significantly decreased incidence of prostate cancer. The incidence of prostate cancer in Indian and Pakistani men showed convergence towards the rates in the white population, suggesting the existence of modifiable risk factors in these men. Most other variations in these data are consistent with international comparisons, and indicate that genetic variations in susceptibility are very influential.
Infiltration of polymorphonuclear cells into the post‐ischaemic myocardium is dependent on β2 and α4 integrins
Authors: Légaré Jean‐Francois , Oxner Adam , Heimrath Olivier , Issekutz Thomas
Published: June 2007

Polymorphonuclear cells (PMN) are believed to be important effector cells responsible the myocardial damage seen following ischaemia. However, the exact kinetics of their migration remains controversial. Isolated PMN (10 × 106 cells) labelled with 51Cr were injected into four groups of Lewis rats: 0 h (T0h; n = 13), 2 h (T2h; n = 7), 4 h (T4h; n = 7) or 6 h following ischaemia (T6h; n = 4). In all recipients, a left thoracotomy and ligation of the left anterior descending coronary was performed. Control animals underwent sham thoracotomy (n = 10). All animals were killed at 24 h and the radioactivity in the tissue measured to estimate labelled PMN migration. Monoclonal antibody blockade was also performed in experimental animals to assess the contribution of β2 and α4 integrins to the PMN migration (n = 32). Labelled PMN migration to the myocardium was similar in all experimental groups, T0–T6h (7.2–11 × 105 labelled PMN) and significantly higher than sham controls (2.2 × 105 labelled PMN; P = 0.03). In contrast PMN migration to dermal inflammatory sites was highest in T0h group, and reached background level in the T4h and T6h groups. β2 integrin blockade inhibited labelled PMN migration by 32%. Blockade of α4 integrin inhibited PMN migration by 30% while the combined β2 + α4 blockade resulted in 63% inhibition of labelled PMN migration compared to treatment with isotype control antibody (P = 0.035). PMN migration following myocardial ischaemia persists over several hours after myocardial infarction and does not follow similar migration kinetics to dermal inflammation. Our findings also suggest that PMN migration is dependent equally on β2 and α4 integrins.
Long‐term interactions between Mediterranean climate, vegetation and fire regime at Lago di Massaciuccoli (Tuscany, Italy)
Authors: COLOMBAROLI DANIELE , MARCHETTO ALDO , TINNER WILLY
Published: June 2007

A Holocene sedimentary sequence from a coastal lake in the Mediterranean area (Lago di Massaciuccoli, Tuscany, Italy, 0 m a.s.l.) was sampled for pollen and microscopic charcoal analyses. Contiguous 1‐cm samples represent an estimated time interval of c. 13 years, thus providing a high‐resolution sequence from 6100 to 5400 cal. years bp.

Just before 6000 cal. years bp, sub‐Mediterranean and Mediterranean forests were present together with fir (Abies alba), a submontane species that is today absent at low altitudes in the Mediterranean. A sharp vegetational change occurred after 6000 cal. years bp involving a drastic decline of Abies alba around the site.

Time‐series analyses suggest that increased fire activity at this time caused a strong decline in Abies alba, a highly fire‐sensitive species. During 100 years of higher fire incidence, diverse (predominantly evergreen) forest communities were converted to low‐diversity fire‐prone shrub communities.

Cross‐correlations reveal that fire during the mid‐Holocene hindered the expansion of holm oak (Quercus ilex), the most common tree species today in Mediterranean environments. While the factors that triggered the Holocene expansion of this species in the Mediterranean area are unclear, our results do not support the hypothesis that fire was key for holm oak expansion.

Diatom analyses of the same sediment core provide an independent palaeoenvironmental proxy for palaeoclimatic reconstruction. A change in the eutrophy and salinity of the lake occurred just before 6000 cal. years bp, suggesting that a climatic shift towards aridity may have triggered the observed change in hydrology and possibly also in fire regime.

Over the millennia fire has decisively contributed to the establishment of the present fire‐adapted vegetation type (macchia). Native fire‐sensitive species were displaced or repressed, and arboreal vegetation became less diverse. Combined ecological and palaeoecological data may help to assess possible future scenarios of biosphere responses to global change. Our results imply that the forecasted global warming and fire increase may trigger irrecoverable biodiversity losses and shifts in vegetational composition within a few decades or centuries at most. In particular, fire and drought‐sensitive vegetation types, such as the relict forests of Abies alba in the Apennines, seem particularly threatened by large‐scale displacement.
Ecosystem engineering facilitates invasions by exotic plants in high‐Andean ecosystems
Authors: BADANO ERNESTO I. , VILLARROEL ELISA , BUSTAMANTE RAMIRO O. , MARQUET PABLO A. , CAVIERES LOHENGRIN A.
Published: June 2007

Ecosystem engineers are organisms that change abiotic conditions in ways that affect the performance and distribution of other species, including exotics. Several mechanisms have been proposed for the successful establishment of exotic plants in natural communities, but the positive effects that native engineer species may have on the distribution and performance of exotic plants remain unknown.

In this study, we propose that amelioration of extreme abiotic conditions by ecosystem engineers can make stressful habitats invadable by exotic plant species, with larger positive effects on the performance of exotic plants as environmental harshness increases. We tested this hypothesis by assessing the effects of a high‐Andean ecosystem engineer, the cushion plant Azorella monantha, which is known to create habitat patches where environmental conditions are less extreme than in the surrounding habitats, on the distribution and the performance of two exotic plant species, field chickweed (Cerastium arvense) and common dandelion (Taraxacum officinale), along a an elevation gradient in the Andes of central Chile.

We measured and compared the abundance, biomass and survival of both exotic species within and outside cushion habitat patches at three elevations (3200 m, 3400 m and 3600 m), and evaluated whether the effects of A. monantha varied across elevations.

The results indicated that cushion plants positively impact the performance of both exotics, and have greater facilitative effects at higher elevations. Indeed, at the higher elevation site, C. arvense was only detected within A. monantha patches, suggesting that cushions may expand the distribution range of exotics. These results suggest that ecosystem engineering by native species could promote biological invasions in harsh environments, leading to higher abundances of invaders than those expected in the absence of engineers.

Given the conspicuousness of ecosystem engineering in nature, we suggest that exotic species eradication programmes might be less successful by not taking into account the facilitative effects of native engineer species on invaders. Further, we suggest that the recent proposals to use engineer species in ecosystem restoration should be aware of their potential role in promoting invasions.
Links between arterial and venous disease
Authors: Prandoni P.
Published: June 2007

An increasing body of evidence suggests the likelihood of a link between arterial and venous disease. According to the results of recent studies, atherosclerosis and venous thromboembolism (VTE) share common risk factors, including age, obesity, diabetes mellitus and metabolic syndrome. Atherosclerosis has the potential to promote the development of thrombotic disorders in the venous system. Another scenario assumes that the two clinical conditions are simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system. Several recent studies have consistently shown that patients with VTE of unknown origin are at a higher risk of cardiovascular diseases, including atherosclerotic complications, than patients with secondary VTE and matched control individuals. Future studies are needed to clarify the nature of this association, to assess its extent and to evaluate its implications for clinical practice.
Inhibition of HIV‐1 entry by antibodies: potential viral and cellular targets
Authors: Phogat S. , Wyatt R. T. , Karlsson Hedestam G. B.
Published: June 2007

Vaccine‐induced antibodies that interfere with viral entry are the protective correlate of most existing prophylactic vaccines. However, for highly variable viruses such as HIV‐1, the ability to elicit broadly neutralizing antibody responses through vaccination has proven to be extremely difficult. The major targets for HIV‐1 neutralizing antibodies are the viral envelope glycoprotein trimers on the surface of the virus that mediate receptor binding and entry. HIV‐1 has evolved many mechanisms on the surface of envelope glycoproteins to evade antibody‐mediated neutralization, including the masking of conserved regions by glycan, quaternary protein interactions and the presence of immunodominant variable elements. The primary challenge in the development of an HIV‐1 vaccine that elicits broadly neutralizing antibodies therefore lies in the design of suitable envelope glycoprotein immunogens that circumvent these barriers. Here, we describe neutralizing determinants on the viral envelope glycoproteins that are defined by their function in receptor binding or by rare neutralizing antibodies isolated from HIV‐infected individuals. We also describe the nonvariable cellular receptors involved in the HIV‐1 entry process, or other cellular proteins, and ongoing studies to determine if antibodies against these proteins have efficacy as therapeutic reagents or, in some cases, as vaccine targets to interfere with HIV‐1 entry.