688 research outputs found
Taxonomy, biostratigraphy, and phylogeny of Oligocene Ciperoella n. gen.
Ciperoella Olsson and Hemleben n. gen. is
erected for Oligocene spinose species that have
a neogloboquadrinid-type wall texture and 4½-5
similarly sized chambers in the final whorl. Four
species are recognized as distinct, namely Ciperoella anguliofficinalis (Blow), Ciperoella angulisuturalis
(Bolli), Ciperoella ciperoensis (Bolli), and Ciperoella
fariasi (Bermúdez). Their taxonomy, phylogeny, and
biostratigraphy is discussed
Taxonomy, biostratigraphy, and phylogeny of Oligocene and lower Miocene Globoturborotalita
The taxonomy, phylogeny and biostratigraphy of
Oligocene and lower Miocene Globoturborotalita is
reviewed. Globoturborotalita is a long-ranging genus appearing in the basal Eocene and still present
in modern oceans with one living representative G.
rubescens. Species attributed to this genus are generally common and cosmopolitan. The following
species are recognized as valid: Globoturborotalita
barbula Pearson and Wade, Globoturborotalita bassriverensis Olsson and Hemleben, Globoturborotalita brazieri (Jenkins), Globoturborotalita cancellata
(Pessagno), Globoturborotalita connecta (Jenkins), Globoturborotalita eolabiacrassata Spezzaferri and
Coxall n. sp., Globoturborotalita euapertura (Jenkins), Globoturborotalita gnaucki (Blow and Banner), Globoturborotalita labiacrassata (Jenkins),
Globoturborotalita martini (Blow and Banner),
Globoturborotalita occlusa (Blow and Banner), Globoturborotalita ouachitaensis (Howe and Wallace),
Globoturborotalita paracancellata Olsson and Hemleben n. sp., Globoturborotalita pseudopraebulloides
Olsson and Hemleben n. sp., and Globoturborotalita
woodi (Jenkins)
Taxonomy, biostratigraphy, and phylogeny of Oligocene and lower Miocene Dentoglobigerina and Globoquadrina
The taxonomy, phylogeny, and biostratigraphy of
Oligocene and lower Miocene Dentoglobigerina
and Globoquadrina are reviewed. Because of the
discovery of spine holes in various species assigned
to these genera, the entire group is now considered to
have been fully or sparsely spinose in life and hence
part of Family Globigerinidae. One new species,
Dentoglobigerina eotripartita Pearson, Wade, and
Olsson n. sp., is named. Dentoglobigerina includes
forms with and without umbilical teeth and species
for which the presence or absence of a tooth is a
variable feature. A significant finding has been the
triple synonymy of Globigerina tripartita Koch,
Globigerina rohri Bolli, and Globoquadrina dehiscens
praedehiscens Blow, which greatly simplifies part of
the taxonomy. The genus Globoquadrina is restricted
to its type species, Globigerina dehiscens Chapman and
others. The following species from the time interval
of interest are regarded as valid: Dentoglobigerina altispira (Cushman and Jarvis), Dentoglobigerina
baroemoenensis (LeRoy), Dentoglobigerina
binaiensis (Koch), Dentoglobigerina eotripartita
Pearson, Wade, and Olsson n. sp., Dentoglobigerina
galavisi (Bermúdez), Dentoglobigerina
globosa (Bolli), Dentoglobigerina globularis
(Bermúdez), Dentoglobigerina juxtabinaiensis
Fox and Wade, Dentoglobigerina larmeui (Akers),
Dentoglobigerina prasaepis (Blow), Dentoglobigerina
pseudovenezuelana (Blow and Banner),
Dentoglobigerina sellii (Borsetti), Dentoglobigerina
taci Pearson and Wade, Dentoglobigerina tapuriensis
(Blow and Banner), Dentoglobigerina tripartita
(Koch), Dentoglobigerina venezuelana (Hedberg),
and Globoquadrina dehiscens (Chapman, Parr,
and Collins). The genus Dentoglobigerina also
comprises other Neogene/Quaternary species not
listed, including the living species Dentoglobigerina
cf. conglomerata (Schwager)
Histidine-Rich Glycoprotein Can Prevent Development of Mouse Experimental Glioblastoma
Extensive angiogenesis, formation of new capillaries from pre-existing blood vessels, is an important feature of malignant glioma. Several antiangiogenic drugs targeting vascular endothelial growth factor (VEGF) or its receptors are currently in clinical trials as therapy for high-grade glioma and bevacizumab was recently approved by the FDA for treatment of recurrent glioblastoma. However, the modest efficacy of these drugs and emerging problems with anti-VEGF treatment resistance welcome the development of alternative antiangiogenic therapies. One potential candidate is histidine-rich glycoprotein (HRG), a plasma protein with antiangiogenic properties that can inhibit endothelial cell adhesion and migration. We have used the RCAS/TV-A mouse model for gliomas to investigate the effect of HRG on brain tumor development. Tumors were induced with platelet-derived growth factor-B (PDGF-B), in the presence or absence of HRG. We found that HRG had little effect on tumor incidence but could significantly inhibit the development of malignant glioma and completely prevent the occurrence of grade IV tumors (glioblastoma)
Taxonomy, biostratigraphy, and phylogeny of Oligocene and early Miocene Paragloborotalia and Parasubbotina
The taxonomy, phylogeny, and biostratigraphy of
Oligocene and early Miocene Paragloborotalia and
Parasubbotina are reviewed. The two genera are
closely related; Paragloborotalia was derived from
Parasubbotina in the early Eocene. Parasubbotina
was more diverse during the middle Eocene, while
Paragloborotalia experienced considerable diversification during the mid-Oligocene and in the latest
Oligocene-earliest Miocene. A significant finding has
been the synonymization of Globorotalia (Tuborotalia) mendacis Blow, and Turborotalia primitiva Brӧnnimann and Resig with Globorotalia birnageae Blow.
The following species from the time interval of interest are regarded as valid: Paragloborotalia acrostoma
(Wezel), Paragloborotalia birnageae (Blow), Paragloborotalia continuosa (Blow), Paragloborotalia
incognita (Walters) Paragloborotalia kugleri (Bolli),
Paragloborotalia mayeri (Cushman and Ellisor),
Paragloborotalia nana (Bolli), Paragloborotalia opima
(Bolli), Paragloborotalia pseudocontinuosa (Jenkins),
Paragloborotalia pseudokugleri (Blow), Paragloborotalia semivera (Hornibrook), Paragloborotalia siakensis (LeRoy), Parasubbotina hagni (Gohrbandt),
and Parasubbotina varianta (Subbotina).
Paragloborotalia is a long-lived group of
planktonic foraminifera that spanned the early Eocene to late Miocene and provided the root stock for
the evolution of multiple smooth, nonspinose, and
keeled globorotaliid lineages during the Neogene.
The early Oligocene forms of Paragloborotalia (nana,
opima, siakensis, pseudocontinuosa) have 4 or 5 globular chambers in the final whorl with radial spiral
sutures and a broadly rounded periphery. A trend
from radial to curved spiral sutures is observed in
late Oligocene and earliest Miocene lineages. Most
species of Paragloborotalia had wide distributions,
but some were more common in tropical to warm
subtropical waters (e.g., siakensis, kugleri) and were
especially dominant in the equatorial Pacific divergence zone (e.g., nana, opima, and pseudocontinuosa)
analogous to modern tropical upwelling Neogloboquadrina. Other species thrived in cool subtropical
and temperate waters (e.g., acrostoma, incognita)
No Detectable Fertility Benefit from a Single Additional Mating in Wild Stalk-Eyed Flies
Background: Multiple mating by female insects is widespread, and the explanation(s) for repeated mating by females has been the subject of much discussion. Females may profit from mating multiply through direct material benefits that increase their own reproductive output, or indirect genetic benefits that increase offspring fitness. One particular direct benefit that has attracted significant attention is that of fertility assurance, as females often need to mate multiply to achieve high fertility. This hypothesis has never been tested in a wild insect population.Methodology/Principal Findings: Female Malaysian stalk-eyed flies (Teleopsis dalmanni) mate repeatedly during their lifetime, and have been shown to be sperm limited under both laboratory and field conditions. Here we ask whether receiving an additional mating alleviates sperm limitation in wild females. In our experiment one group of females received a single additional mating, while a control group received an interrupted, and therefore unsuccessful, mating. Females that received an additional mating did not lay more fertilised eggs in total, nor did they lay proportionately more fertilised eggs. Female fertility declined significantly through time, demonstrating that females were sperm limited. However, receipt of an additional mating did not significantly alter the rate of this decline.Conclusions/Significance: Our data suggest that the fertility consequences of a single additional mating were small. We discuss this effect (or lack thereof), and suggest that it is likely to be attributed to small ejaculate size, a high proportion of failed copulations, and the presence of X-linked meiotic drive in this species
Predictive factors of developing diabetes mellitus in women with gestational diabetes.
BACKGROUND: To investigate which factors during gestational diabetes pregnancies correlate with the risk of developing impaired glucose tolerance or diabetes 1 year postpartum and to compare this risk in women with gestational diabetes and women with a normal oral glucose tolerance test during pregnancy. METHODS: Of 315 women with gestational diabetes, defined as a 2-hr blood glucose value of at least 9.0 mmol/l at a 75-g oral glucose tolerance test, who delivered in Lund 1991-99, 229 (73%) performed a new test 1 year postpartum. We compared maternal and fetal factors during pregnancy with the test value at follow up. A control group of 153 women with a 2-hr test value below 7.8 mmol/l during pregnancy were invited to a new test 1 year postpartum and 60 (39%) accepted. RESULTS: At 1 year follow up, 31% of the women with gestational diabetes but only one of the 60 controls showed pathologic glucose tolerance and one had developed diabetes. The following factors in women with gestational diabetes were identified as predicting impaired glucose tolerance or diabetes at 1 year follow up: maternal age over 40 and--in a multiple regression analysis, independent of each other--a high 2-hr value at oral glucose tolerance test during pregnancy and insulin treatment during pregnancy. CONCLUSION: The risk of developing manifest diabetes after gestational diabetes may be high enough to justify a general screening or diagnostic procedure in all pregnant women to identify women with gestational diabetes and a postpartum follow up program for them. This study did not identify any particular factor during pregnancy with enough precision to predict a later progression to diabetes
Feasibility and safety of high-dose adenosine perfusion cardiovascular magnetic resonance
<p>Abstract</p> <p>Introduction</p> <p>Adenosine is the most widely used vasodilator stress agent for Cardiovascular Magnetic Resonance (CMR) perfusion studies. With the standard dose of 140 mcg/kg/min some patients fail to demonstrate characteristic haemodynamic changes: a significant increase in heart rate (HR) and mild decrease in systolic blood pressure (SBP). Whether an increase in the rate of adenosine infusion would improve peripheral and, likely, coronary vasodilatation in those patients is unknown. The aim of the present study was to assess the tolerance and safety of a high-dose adenosine protocol in patients with inadequate haemodynamic response to the standard adenosine protocol when undergoing CMR perfusion imaging.</p> <p>Methods</p> <p>98 consecutive patients with known or suspected coronary artery disease (CAD) underwent CMR perfusion imaging at 1.5 Tesla. Subjects were screened for contraindications to adenosine, and an electrocardiogram was performed prior to the scan. All patients initially received the standard adenosine protocol (140 mcg/kg/min for at least 3 minutes). If the haemodynamic response was inadequate (HR increase < 10 bpm or SBP decrease < 10 mmHg) then the infusion rate was increased up to a maximum of 210 mcg/kg/min (maximal infusion duration 7 minutes).</p> <p>Results</p> <p>All patients successfully completed the CMR scan. Of a total of 98 patients, 18 (18%) did not demonstrate evidence of a significant increase in HR or decrease in SBP under the standard adenosine infusion rate. Following the increase in the rate of infusion, 16 out of those 18 patients showed an adequate haemodynamic response. One patient of the standard infusion group and two patients of the high-dose group developed transient advanced AV block. Significantly more patients complained of chest pain in the high-dose group (61% vs. 29%, p = 0.009). On multivariate analysis, age > 65 years and ejection fraction < 57% were the only independent predictors of blunted haemodynamic responsiveness to adenosine.</p> <p>Conclusions</p> <p>A substantial number of patients do not show adequate peripheral haemodynamic response to standard-dose adenosine stress during perfusion CMR imaging. Age and reduced ejection fraction are predictors of inadequate response to standard dose adenosine. A high-dose adenosine protocol (up to 210 mcg/kg/min) is well tolerated and results in adequate haemodynamic response in nearly all patients.</p
Mural Cell Associated VEGF Is Required for Organotypic Vessel Formation
Background: Blood vessels comprise endothelial cells, mural cells (pericytes/vascular smooth muscle cells) and basement membrane. During angiogenesis, mural cells are recruited to sprouting endothelial cells and define a stabilizing context, comprising cell-cell contacts, secreted growth factors and extracellular matrix components, that drives vessel maturation and resistance to anti-angiogenic therapeutics. Methods and Findings: To better understand the basis for mural cell regulation of angiogenesis, we conducted high content imaging analysis on a microtiter plate format in vitro organotypic blood vessel system comprising primary human endothelial cells co-cultured with primary human mural cells. We show that endothelial cells co-cultured with mural cells undergo an extensive series of phenotypic changes reflective of several facets of blood vessel formation and maturation: Loss of cell proliferation, pathfinding-like cell migration, branching morphogenesis, basement membrane extracellular matrix protein deposition, lumen formation, anastamosis and development of a stabilized capillary-like network. This phenotypic sequence required endothelial-mural cell-cell contact, mural cell-derived VEGF and endothelial VEGFR2 signaling. Inhibiting formation of adherens junctions or basement membrane structures abrogated network formation. Notably, inhibition of mural cell VEGF expression could not be rescued by exogenous VEGF. Conclusions: These results suggest a unique role for mural cell-associated VEGF in driving vessel formation and maturation
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