bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dietary selenium deficiency as well as excess supplementation induces multiple defects in mouse epididymal spermatozoa: understanding the role of selenium in male fertility
Authors: Shalini Sonia , Bansal M. P. 
Published: July 2007

SummarySelenium (Se) is essential for male fertility. The present study was carried out to observe the defects associated with Se deficiency as well as excess Se supplementation by analyzing the sperm ultrastructure and chromatin organization. Different Se status mice were generated viz. Se deficient (group I), Se adequate (group II) and Se excess (group III) by feeding the respective diets for a period of 4 (group Ia, IIa and IIIa) and 8 weeks (group Ib, IIb and IIIb). Reduction in sperm concentration, motility and percentage fertility was observed in Se deficient and Se excess groups. Electron microscopy revealed mitochondrial swelling and gaps between adjacent mitochondria in mice fed Se‐deficient diet for 4 weeks. At 8 weeks, several abnormalities such as loose contact of the mitochondrial helix with the plasma membrane, loss of mitochondria, retention of cytoplasmic droplet, fracturing of outer dense fibres and presence of both the midpiece and the principal piece cross‐sections in a common plasma membrane were observed. In Se excess group, the predominant defect was the frequent presence of equidistant, cross‐sectioned midpieces of the tail embedded in a common cytoplasm. These defects are indicative of loss of sperm motility. Spermatozoa from Se‐deficient mice had incompletely condensed chromatin and indicated an increase in occurrence of DNA strand breaks. The animals fed Se excess diet also indicated increase in DNA breaks but this was significantly less than the deficient diet fed groups. Our study reveals the defects associated with Se deficiency that result in loss of reproductive ability and also reflects its possible harmful effects on spermatozoa after prolonged consumption at supranutritional level.
Splenic cytokines in mice immunized with testicular germ cells
Authors: Tokunaga Yo , Terayama Hayato , Naito Munekazu , Qu Ning , Hirai Shuichi , Ogawa Yuki , Yi Shuang‐Qin , Itoh Masahiro 
Published: July 2007

SummaryWe previously established that two subcutaneous injections of viable syngeneic testicular germ cells (TGC) alone can induce CD4+ T cell‐dependent experimental autoimmune orchitis (EAO) in mice. This model is histologically characterized by lymphocytic infiltration into the testes and the following aspermatogenesis. In the present study, we investigated the dynamics of splenic cytokines in EAO, using specific enzyme‐linked immunosorbent assay. We found that splenic production of both type 1 helper T cell (Th1) and type 2 helper T cell (Th2)‐related cytokines increased after the second but not the first immunization with TGC, indicating that secondary immune responses are critical to the EAO induction. However, the production of Th1‐related cytokines became predominant at the clinical stage of EAO. Additionally, serum FSH and inhibin‐B increased and decreased, respectively, during EAO. On the other hand, LH did not significantly change and testosterone temporally increased during the same period. These results indicate that both Th1‐ and Th2‐related cytokines are involved at the pre‐clinical phase of EAO, but that Th1‐ rather than Th2‐related cytokines are responsible for the clinical phase when spermatogenesis is disrupted but the Leydig cell function is well preserved.
Morphometric changes in boar spermatozoa induced by cryopreservation
Authors: García‐Herreros M. , Barón F. J. , Aparicio I. M. , Santos A. J. , García‐Marín L. J. , Gil M. C. 
Published: July 2007

SummaryComputer‐assisted sperm morphometry analysis was used to determine the effects of cryopreservation on boar sperm head and midpiece morphometry. Sperm‐rich fractions were collected from five mature boars. Three microscope slides were prepared from single extended sperm samples prior freezing and post‐thawing. All slides were stained with Hemacolor, and 250 sperm images were obtained from each slide. The sperm head dimensions for length, width, area, perimeter and four shape factors and sperm‐midpiece dimensions for area, width, angle and distance were determined in each spermatozoa. The effects of sperm freezing on sperm dimensions within and among boars were determined. A previous discriminant analysis of the results was able to correctly classify a 78.3 and 82% of fresh and frozen‐thawed spermatozoa respectively. Sperm heads were significantly smaller in cryopreserved spermatozoa than in the companion extended samples for length, width, area and perimeter. Sperm midpieces were also significantly smaller in cryopreserved spermatozoa for width and area. The highest changes in morphometric dimensions after the freeze‐thawing process were found in the midpiece of spermatozoa. The variability of morphometric measurements only was significantly different between fresh and thawed samples for head rugosity and midpiece area. The effects of cryopreservation on morphometric parameters were similar in the boars, which allow us to conclude that cryopreservation process does not have a different effect in each individual boar. In summary, morphometric changes associated with the cryopreservation process on boar spermatozoa do not apparently depends on an effect at individual level.
Prediction of spontaneous conception based on semen parameters
Authors: Jedrzejczak Piotr , Taszarek‐Hauke Grazyna , Hauke Jan , Pawelczyk Leszek , Duleba Antoni J. 
Published: July 2007

SummaryAccurate prognosis of male fertility based on semen measurements is still not straightforward. This study was designed to identify the best predictors of fertility and to develop a multiple regression model predicting fertility using selected parameters of semen analysis. The predictive value of standard semen parameters and selected functional tests were studied in 113 fertile men and in 109 subfertile men whose spouses had a normal infertility workup. Individual semen parameters were evaluated using the receiver operating characteristic curve. Logistic regression based on linear functions of analysed sperm parameters was used to predict the chance of spontaneous conception. Logistic regression modelling revealed that the best prediction of spontaneous conception was obtained using 12 semen parameters: sperm concentration, total progressive motility (A + B), motility grade C or D, normal sperm morphology, defects of: head, acrosome, midpiece and tail, spontaneous acrosome reaction, hypo‐osmotic swelling (HOS) test and acid aniline blue test. This mathematical model reached 90.3% accuracy in predicting in vivo conception and 90.8% for its lack. A satisfactory prediction of male fertility was also obtained using only four semen measurements: sperm concentration, total progressive motility (grade A + B), normal morphology, and HOS test; this model correctly identified as fertile 84.1% of those who conceived and identified as subfertile 88.1% of those who did not achieve pregnancy. In conclusion, basic semen analysis and selected functional tests of sperm provide important information regarding male fertility status.
Polymorphisms in CYP1A1 gene are associated with male infertility in a Chinese population
Authors: Lu Ningxia , Wu Bin , Xia Yankai , Wang Wei , Gu Aihua , Liang Jie , Lu Chuncheng , Song Lin , Wang Shoulin , Peng Yuzhu , Zhang Zhengdong , Wang Xinru 
Published: July 2007

SummaryCytochrome P4501A1 (CYP1A1) is a key enzyme in phase I bioactivation of polycyclic aromatic hydrocarbons (PAHs), which have potential reproductive toxicity. The aim of this study was to investigate the association of the CYP1A1 polymorphisms with male infertility in a Han‐Chinese population. We genotyped two polymorphisms, CYP1A1*2A and CYP1A1*2C, using polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) assay in a hospital‐based case–control study including 192 infertile patients with non‐obstructive azoospermia or severe oligozoospermia and 226 fertile controls. We found that the genotype distribution of CYP1A1*2C was significantly different between the patients and the controls (p = 0.019). Analysis showed that CYP1A1*2C AG genotype was associated with a significantly decreased risk of male infertility [odds ratio (OR) = 0.56, 95% confidence interval (95% CI) = 0.36–0.86, p = 0.005] compared with the AA genotype. A statistically significantly decreased risk of male infertility was found to be associated with the CYP1A1*2C AG genotype plus GG genotype compared with CYP1A1*2C AA genotype (OR = 0.60, 95% CI = 0.40–0.91, p = 0.011). No significant association was detected between CYP1A1*2A polymorphism and male infertility. Haplotypic analysis showed a significantly increased risk of male infertility associated with the C‐A haplotype compared with the T‐A haplotype (OR = 1.98, 95% CI = 1.27–3.09), indicating a synergic effect of the two polymorphisms. Our results suggest that the CYP1A1 polymorphisms may contribute to the pathogenesis of male infertility in the Han‐Chinese population.
Linking agricultural policies to population trends of Swedish farmland birds in different agricultural regions
Authors: WRETENBERG JOHAN , LINDSTRÖM ÅKE , SVENSSON SÖREN , PÄRT TOMAS 
Published: July 2007

Summary

The widespread declines of farmland birds have generally been linked to agricultural intensification. We tested the hypotheses that (i) changes in agricultural policy, through its effects on agricultural intensification and (ii) regional differences in agricultural intensification affect temporal and spatial population trends of farmland birds in Sweden.
We analysed regional bird population trends (1976–2003) for seven common farmland bird species: the migratory lapwing Vanellus vanellus, skylark Alauda arvensis, starling Sturnus vulgaris and linnet Carduelis cannabina and the resident tree sparrow Passer montanus, house sparrow P. domesticus and yellowhammer Emberiza citrinella. We identified three periods of agricultural policy in Sweden between 1976 and 2003: the intensification period (i.e. 1976–87; promoting increased production), the set‐aside period (1987–95; promoting extensification of farming) and the Common Agricultural Policy (CAP) period (1995–2003; promoting increased production). Population trends were compared between three types of Swedish farmlands: open plains (intensive farming with a marked intensification), mosaic farmlands (i.e. farmland‐dominated forest mosaics, less intensive farming, but show moderate intensification) and forest regions (i.e. forest‐dominated farmlands with low intensity farming and extensification/abandonment).
The four migrants displayed clear significant trend switches between the policy periods, with declines in the ‘intensification period’ and the ‘CAP period’ and less negative or even positive population trends in the ‘set‐aside period’. The population trends of the three resident species showed no clear pattern in relation to agricultural policy periods.
All species except tree sparrow displayed significantly different population trends between farmland regions. Four species (lapwing, skylark, linnet and house sparrow) declined most in the open plains and the forest regions, whereas two species (starling and yellowhammer) declined most in the mosaic farmlands.
Synthesis and applications. Large‐scale changes in agriculture policy have a strong potential to change the present poor state of farmland biodiversity as shown by the generally positive population trends in the ‘set‐aside period’. It also suggests extensification to be beneficial to farmland birds. However, in regions of low profitability and an already ongoing extensification, a further extensification will lead to loss of both farmland habitat and bird diversity. In such regions mixed farming needs to be retained and hence should be supported.
Long‐term effects of human impact on mountainous ecosystems, western Taurus Mountains, Turkey
Authors: Kaniewski D. , De Laet V. , Paulissen E. , Waelkens M. 
Published: July 2007

AbstractAim  To investigate the human impact on eastern Mediterranean ecosystems in a subhumid to semi‐arid region of the Near East.Location  This paper considers data from Bereket (1410–1440 m a.s.l.), an intramontane basin surrounded by the Kokayanık Tepe (1830 m a.s.l.) and the Beşparmak Dağları (2280 m a.s.l.), in the western Taurus Mountains of south‐west Turkey.Methods  Late Holocene samples were collected along an 800‐cm‐deep sediment profile cored in the secondary valley of the Bereket basin. Descriptive vegetation data and modern pollen samples (moss polsters) were collected at elevational intervals of c. 15 m along an altitudinal transect from the Bereket basin (over Tepe Düzen, 1600 m a.s.l.) to Ağlasun Dağı (1700 m a.s.l.). Information about the spatial distribution of the present land cover was obtained from ASTER satellite imagery. Digital elevation‐derived data and geological information were used to examine the relationship between actual land cover and other environmental variables.Results  The well dated Bereket sequence provides a unique record of biennial‐to‐decadal landscape changes driven primarily by intensive human impact from 360 cal. yr bc to 650 cal. yr ad. Since 360 cal. yr bc, over‐exploitation of the land has led to altitudinal variation of tree lines, a destruction of the natural forest ecosystems (Pinus–Quercus cerris mixed forest), and an extensive spread of forest‐steppe in the highlands. The present‐day distribution of vegetation in the basin area shows that human activities remain the major factor influencing the character of modern ecosystems.Main conclusions  This research demonstrates the long‐term local destructive effects of human impacts on the mountainous ecosystems in a small Anatolian intramontane basin since 360 cal. yr bc, and the capacity of these ecosystems to recover during periods of reduced human impact. The late Holocene history and modern vegetation characteristics show that the past and present‐day distribution and composition of vegetation are influenced primarily by human activity, and that substrate, elevation, slope and orientation are of secondary significance.
Glacial refugia for summer‐green trees in Europe and south‐west Asia as proposed by ECHAM3 time‐slice atmospheric model simulations
Authors: Leroy Suzanne A. G. , Arpe Klaus 
Published: July 2007

AbstractAim To generate maps of potential refugia for summer‐green trees during the Last Glacial Maximum (LGM).Locations Southern Europe and south‐western Asia.Methods Time‐slice simulations of the atmospheric climate with the ECHAM3 model are used for the LGM. Limiting factors beyond which cool and warm groups of deciduous trees cannot grow (such as temperature in growing degree days, minimum monthly temperature and precipitation in summer) are chosen. A limited validation by fossil pollen and charcoal records from LGM sites was done.Results Two sets of maps extending from Europe to the Caspian region for cool and warm summer‐green trees are presented. Three criteria are combined using contour lines to indicate confidence levels. Small areas within the three southern peninsulas of Europe (Spain, Italy and Greece) are highlighted as possible refugia for summer‐green trees. Further, areas that have remained poorly known are now proposed as refugia, including the Sakarya–Kerempe region in northern Turkey, the east coast of the Black Sea and the area south of the Caspian Sea.Main conclusions The maps produced in this study could be used to facilitate better long‐term management for the protection of European and south‐western Asian biodiversity.
Plasticity of synaptic endings in the cochlear nucleus following noise‐induced hearing loss is facilitated in the adult FGF2 overexpressor mouse
Authors: D'Sa Chrystal , Gross Julia , Francone Victor P. , Morest D. Kent 
Published: July 2007

AbstractIn adult mammals a single exposure to loud noise can damage cochlear hair cells and initiate subsequent episodes of degeneration of axonal endings in the cochlear nucleus (CN). Possible mechanisms are loss of trophic support and/or excitotoxicity. Fibroblast growth factor 2 (FGF2), important for development, might be involved in either mechanism. To test this hypothesis, we noise‐exposed FGF2 overexpressor mice and observed the effects on synaptic endings by immunolabelling for SV2, a synaptic vesicle protein, at 1, 2, 4, and 8 weeks after noise exposure. SV2 staining was observed in two major locations; perisomatic, representing axo‐somatic terminals, and neuropil, representing axo‐dendritic terminals. The wildtype (WT) lost both perisomatic and neuropil clusters with an intervening period of modest recovery for the perisomatic. In contrast, in the overexpressor, the perisomatic clusters remained unchanged after intervening periods of increase. The neuropil clusters underwent a period of initial decline, followed by a transient recovery and ultimate decline. Changes in SV2 immunostaining correlated with changes in vesicular glutamate and GABA transporters at synapses and, in the overexpressor, with staining changes for FGF2 and FGF receptor 1. These molecules may contribute to the synaptic reorganization after noise damage; they may protect and/or aid recovery of synapses after overstimulation.
Subventricular zone neuronal progenitors undergo multiple divisions and retract their processes prior to each cytokinesis
Authors: Coskun Volkan , Falls Douglas L. , Lane Richard , Czirok Andras , Luskin Marla B. 
Published: July 2007

AbstractMitotically active progenitor cells from the anterior portion of the forebrain subventricular zone (SVZa), which give rise throughout life to olfactory bulb interneurons, bear processes and express neuronal markers. To understand how rodent SVZa neuronal progenitors coordinate division and process formation, we used time‐lapse videomicroscopy to analyse the proliferative behavior of SVZa progenitors in dissociated cell culture continuously for up to five generations. The cell cycle time of these cultured SVZa cells assessed videomicroscopically (cytokinesis to cytokinesis) was similar to the cell cycle time along the rostral migratory stream in vivo (14–17 h). The relationship between process extension, process retraction and cytokinesis was assessed quantitatively for 120 cells undergoing cytokinesis. Although all of these cells had elaborated processes, virtually all of them completely withdrew their processes prior to cytokinesis. Process withdrawal was rapid and tightly coupled to cytokinesis; 50% of the cells studied initiated process retraction within 30 min of cytokinesis and 96% had begun to withdraw their processes within 60 min of cytokinesis. In SVZa progenitor cell lineages, the sequence of process extension, process retraction and division is repeated over multiple generations. This complete withdrawal of processes prior to division differentiates SVZa progenitor cells from the characteristics reported for several other process‐bearing types of neural progenitor cells, including sympathetic neuroblasts, cerebral cortical radial glia, and cerebellar and retinal progenitors. Collectively, our findings indicate that SVZa progenitors employ different cellular mechanisms than other neural progenitors to regulate proliferation and differentiation.
Literacy: a cultural influence on functional left–right differences in the inferior parietal cortex
Authors: Petersson Karl Magnus , Silva Carla , Castro‐Caldas Alexandre , Ingvar Martin , Reis Alexandra 
Published: July 2007

AbstractThe current understanding of hemispheric interaction is limited. Functional hemispheric specialization is likely to depend on both genetic and environmental factors. In the present study we investigated the importance of one factor, literacy, for the functional lateralization in the inferior parietal cortex in two independent samples of literate and illiterate subjects. The results show that the illiterate group are consistently more right‐lateralized than their literate controls. In contrast, the two groups showed a similar degree of left–right differences in early speech‐related regions of the superior temporal cortex. These results provide evidence suggesting that a cultural factor, literacy, influences the functional hemispheric balance in reading and verbal working memory‐related regions. In a third sample, we investigated grey and white matter with voxel‐based morphometry. The results showed differences between literacy groups in white matter intensities related to the mid‐body region of the corpus callosum and the inferior parietal and parietotemporal regions (literate > illiterate). There were no corresponding differences in the grey matter. This suggests that the influence of literacy on brain structure related to reading and verbal working memory is affecting large‐scale brain connectivity more than grey matter per se.
Cajal–Retzius cells and subplate neurons differentially express vesicular glutamate transporters 1 and 2 during development of mouse cortex
Authors: Ina Ayuka , Sugiyama Miki , Konno Jinko , Yoshida Sachine , Ohmomo Hideki , Nogami Haruo , Shutoh Fumihiro , Hisano Setsuji 
Published: July 2007

AbstractIn the light of the various neurobiological effects of glutamate in brain development, although some embryonic cells are a probable source of glutamate involved in the development of precursor cells and/or immature neurons, little is known about when and where glutamate plays its crucial roles during corticogenesis. To investigate these roles, we focused on the developmental expression of vesicular glutamate transporter (VGLUT)1 and VGLUT2, which are regarded as the best markers for verifying glutamatergic neuron identity, especially the spatiotemporal distributions of their transcripts and proteins in the developing mouse cortex and hippocampus. In situ hybridization studies revealed that VGLUT1 mRNA is expressed in preplate and marginal zone cells at embryonic day (E)10 and in subplate cells by E13, whereas VGLUT2 mRNA is expressed in preplate and marginal zone cells at E10 and in cells of the subventricular zone by E13. Reverse transcriptase–polymerase chain reaction analysis detected full‐length VGLUT1 and VGLUT2 gene transcripts in the embryonic brain. By dual labeling combined with immunostaining for microtubule‐associated protein 2 (MAP2) or reelin, we showed that MAP2‐positive preplate and marginal zone neurons and subplate neurons express VGLUT1, while reelin‐positive preplate and marginal zone cells and MAP2‐negative subventricular zone cells express VGLUT2. The present study is the first to provide morphologically reliable evidence showing that Cajal–Retzius cells and subplate neurons are glutamatergic, and that the two cells differentially express VGLUT1 and VGLUT2, respectively, as the specific transport system of glutamate in some events orchestrated by these cells during the cortical development of mice.
Flood Disasters and Agricultural Wages in Bangladesh
Authors: Banerjee Lopamudra 
Published: July 2007

ABSTRACTThis article examines the effects of abnormal floods on agricultural wages in Bangladesh. Drawing upon the district‐wise monthly real wage data for the period 1979–2000, it shows that wages decline sharply in the regions that are severely inundated for a long period of time. Wages may remain depressed in these regions even in the post‐flood months. However, wages increase in the flood months in the regions that remain submerged for short durations. The article examines the district‐wise crop yield data to explain these results in terms of the impact of flood on agricultural productivity, and therefore the demand for labour.