258 research outputs found
Histochemical analysis of glycoconjugates in the domestic cat testis
The localization and characterization of
oligosaccharide sequences in the cat testis was
investigated using 12 lectins in combination with the Ăelimination
reaction, N-Glycosidase F and sialidase
digestion. Leydig cells expressed O-linked glycans with
terminal aGalNAc (HPA reactivity) and N-glycans with
terminal/internal aMan (Con A affinity). The basement
membrane showed terminal Neu5Aca2,6Gal/GalNAc,
GalĂ1,3GalNAc, a/ĂGalNAc, and GlcNAc (SNA, PNA,
HPA, SBA, GSA II reactivity) in O-linked oligosaccharides,
terminal GalĂ1,4GlcNAc (RCA120 staining)
and aMan in N-linked oligosaccharides; in addition,
terminal Neu5Aca2,3GalĂ1,4GlcNac, Forssman
pentasaccharide, aGal, aL-Fuc and internal GlcNAc
(MAL II, DBA, GSA I-B4, UEA I, KOH-sialidase-WGA
affinity) formed both O- and N-linked oligosaccharides.
The Sertoli cells cytoplasm contained terminal Neu5Ac-
GalĂ1,4GlcNAc, Neu5Ac-ĂGalNAc as well as internal
GlcNAc in O-linked glycans, aMan in N-linked
glycoproteins and terminal Neu5Aca2,6Gal/
GalNAc in both O- and N-linked oligosaccharides.
Spermatogonia exhibited cytoplasmic N-linked
glycoproteins with aMan residues. The spermatocytes
cytoplasm expressed terminal Neu5Aca2,3GalĂ1,4
GlcNAc and GalĂ1,3GalNAc in O-linked oligosaccharides,
terminal GalĂ1,4GlcNAc and a/ĂGalNAc
in N-linked glycoconjugates. The Golgi region showed
terminal Neu5aca2,3GalĂ1,4GlcNac, GalĂ1,4GlcNAc,
Forssman pentasaccharide, and aGalNAc in O-linked
oligosaccharides, aMan and terminal ĂGal in N-linked
oligosaccharides. The acrosomes of Golgi-phase
spermatids expressed terminal GalĂ1,3GalNAc,
GalĂ1,4GlcNAc, Forssmann pentasaccharide,
a/ĂGalNAc, aGal and internal GlcNAc in O-linked
oligosaccharides, terminal a/ĂGalNAc, aGal and
terminal/internal aMan in N-linked glycoproteins. The
acrosomes of cap-phase spermatids lacked internal
Forssman pentasaccharide and aGal, while having
increased a/ĂGalNAc. The acrosomes of elongated
spermatids did not show terminal GalĂ1,3GalNAc,
displayed terminal GalĂ1,4GlcNAc and a/ĂGalNAc in
N-glycans and Neu5Ac-GalĂ1,3GalNAc in O-linked
oligosaccharides
Wanted dead or alive : high diversity of macroinvertebrates associated with living and âdeadâ Posidonia oceanica matte
The Mediterranean endemic seagrass Posidonia
oceanica forms beds characterised by a dense leaf canopy
and a thick root-rhizome âmatteâ. Death of P. oceanica
shoots leads to exposure of the underlying matte, which
can persist for many years, and is termed âdeadâ matte.
Traditionally, dead matte has been regarded as a degraded
habitat. To test whether this assumption was
true, the motile macroinvertebrates of adjacent living
(with shoots) and dead (without shoots) matte of
P. oceanica were sampled in four different plots located
at the same depth (5â6 m) in Mellieha Bay, Malta
(central Mediterranean). The total number of species
and abundance were significantly higher (ANOVA;
P<0.05 and P<0.01, respectively) in the dead matte
than in living P. oceanica matte, despite the presence of
the foliar canopy in the latter. Multivariate analysis
(MDS) clearly showed two main groups of assemblages,
corresponding to the two matte types. The amphipods
Leptocheirus guttatus and Maera grossimana, and the
polychaete Nereis rava contributed most to the dissimilarity
between the two different matte types. Several
unique properties of the dead matte contributing to the
unexpected higher number of species and abundance of
motile macroinvertebrates associated with this habitat
are discussed. The findings have important implications
for the conservation of bare P. oceanica matte, which
has been generally viewed as a habitat of low ecological
value.peer-reviewe
Histological and immunohistochemical investigation on ovarian development and plasma estradiol levels in the swordfish (<i>Xiphias gladius</i> L.)
The paper reports a histological and immunohistochemical description of oocyte growth and ultrastructural aspects of zona radiata (ZR) formation as well as the relationship between plasma estradiol-17β, (E2 ) levels and ovarian development in swordfish (Xiphias gladius L.) from the Mediterranean Sea. Ovaries were inactive during March to mid April; maturation occurred during late April to June and spawning in June and July. Zona radiata formation starts, as Pas positive material, in oocytes at the lipid stage. In this stage a deposit of electrondense material between oolemma and follicular cells appears. In the cortical alveoli stage and through the early vitellogenic stage, the deposition of a moderately electrondense material occurred on the inner side of the ZR. Finally, in late vitellogenic oocytes a third layer, made of microfibrillar material, appeared. The immunohistochemical analyses revealed that the initial internalisation of hepatic zona radiata proteins (Zrp) in the swordfish oocyte starts before the uptake of vitellogenin (Vtg) and that it is associated with the low previtellogenic E2 plasma levels, while a significant E2 increase in plasma is associated with the beginning of Vtg uptake. This would appear to confirm the hypothesis that the differential and sequential induction of zonagenesis and vitellogenesis may reflect a general feature of teleost oogenesi
High-Sensitivity C-Reactive Protein and Acute Kidney Injury in Patients with Acute Myocardial Infarction: A Prospective Observational Study
Background. Accumulating evidence suggests that inflammation plays a key role in acute kidney injury (AKI) pathogenesis. We explored the relationship between high-sensitivity C-reactive protein (hs-CRP) and AKI in acute myocardial infarction (AMI). Methods. We prospectively included 2,063 AMI patients in whom hs-CRP was measured at admission. AKI incidence and a clinical composite of in-hospital death, cardiogenic shock, and acute pulmonary edema were the study endpoints. Results. Two-hundred-thirty-four (11%) patients developed AKI. hs-CRP levels were higher in AKI patients (45 \ub1 87 vs. 16 \ub1 41 mg/L; p < 0.0001). The incidence and severity of AKI, as well as the rate of the composite endpoint, increased in parallel with hs-CRP quartiles (p for trend <0.0001 for all comparisons). A significant correlation was found between hs-CRP and the maximal increase of serum creatinine (R = 0.23; p < 0.0001). The AUC of hs-CRP for AKI prediction was 0.69 (p < 0.001). At reclassification analysis, addition of hs-CRP allowed to properly reclassify 14% of patients when added to creatinine and 8% of patients when added to a clinical model. Conclusions. In AMI, admission hs-CRP is closely associated with AKI development and severity, and with in-hospital outcomes. Future research should focus on whether prophylactic renal strategies in patients with high hs-CRP might prevent AKI and improve outcome
Spawning Behaviour and Post-spawning Migration Patterns of Atlantic Bluefin Tuna (Thunnus thynnus) Ascertained from Satellite Archival Tags
VersiĂłn del editor
PCSK9 deficiency reduces insulin secretion and promotes glucose intolerance: the role of the low-density lipoprotein receptor
Aims
PCSK9 loss of function genetic variants are associated with lower low-density lipoprotein cholesterol but also with higher plasma glucose levels and increased risk of Type 2 diabetes mellitus. Here, we investigated the molecular mechanisms underlying this association.
Methods and results
Pcsk9 KO, WT, Pcsk9/Ldlr double KO (DKO), Ldlr KO, albumin AlbCre+/Pcsk9LoxP/LoxP (liver-selective Pcsk9 knock-out mice), and AlbCre-/Pcsk9LoxP/LoxP mice were used. GTT, ITT, insulin and C-peptide plasma levels, pancreas morphology, and cholesterol accumulation in pancreatic islets were studied in the different animal models. Glucose clearance was significantly impaired in Pcsk9 KO mice fed with a standard or a high-fat diet for 20\u2009weeks compared with WT animals; insulin sensitivity, however, was not affected. A detailed analysis of pancreas morphology of Pcsk9 KO mice vs. controls revealed larger islets with increased accumulation of cholesteryl esters, paralleled by increased insulin intracellular levels and decreased plasma insulin, and C-peptide levels. This phenotype was completely reverted in Pcsk9/Ldlr DKO mice implying the low-density lipoprotein receptor (LDLR) as the proprotein convertase subtilisin/kexin Type 9 (PCSK9) target responsible for the phenotype observed. Further studies in albumin AlbCre+/Pcsk9LoxP/LoxP mice, which lack detectable circulating PCSK9, also showed a complete recovery of the phenotype, thus indicating that circulating, liver-derived PCSK9, the principal target of monoclonal antibodies, does not impact beta-cell function and insulin secretion.
Conclusion
PCSK9 critically controls LDLR expression in pancreas perhaps contributing to the maintenance of a proper physiological balance to limit cholesterol overload in beta cells. This effect is independent of circulating PCSK9 and is probably related to locally produced PCSK9
Warming, drought, and disturbances lead to shifts in functional composition: A millennial-scale analysis for Amazonian and Andean sites
Tropical forests are changing in composition and productivity, probably in response to changes in climate and disturbances. The responses to these multiple environmental drivers, and the mechanisms underlying the changes, remain largely unknown. Here, we use a functional trait approach on timescales of 10,000Âżyears to assess how climate and disturbances influence the community-mean adult height, leaf area, seed mass, and wood density for eight lowland and highland forest landscapes. To do so, we combine data of eight fossil pollen records with functional traits and proxies for climate (temperature, precipitation, and El NiĂąo frequency) and disturbances (fire and general disturbances). We found that temperature and disturbances were the most important drivers of changes in functional composition. Increased water availability (high precipitation and low El NiĂąo frequency) generally led to more acquisitive trait composition (large leaves and soft wood). In lowland forests, warmer climates decreased community-mean height probably because of increased water stress, whereas in highland forests warmer climates increased height probably because of upslope migration of taller species. Disturbance increased the abundance of acquisitive, disturbance-adapted taxa with small seeds for quick colonization of disturbed sites, large leaves for light capture, and soft wood to attain fast height growth. Fire had weak effects on lowland forests but led to more stress-adapted taxa that are tall with fast life cycles and small seeds that can quickly colonize burned sites. Site-specific analyses were largely in line with cross-site analyses, except for varying site-level effects of El NiĂąo frequency and fire activity, possibly because regional patterns in El NiĂąo are not a good predictor of local changes, and charcoal abundances do not reflect fire intensity or severity. With future global changes, tropical Amazonian and Andean forests may transition toward shorter, drought- and disturbance-adapted forests in the lowlands but taller forests in the highlands.We thank various funding sources. M.T.v.d.S. was supported by the Rubicon research program with project number 019.171LW.023 and the Veni research program with project number NWO-VI.Veni.192.027, both funded by the Netherlands Organisation for Scientific Research (NWO); M.T.v.d.S. and L.P. by the European Research Council Advanced Grant PANTROP 834775; M.B.B. by the National Science Foundation 621 (grant # EAR1338694, BCS0926973 and 1624207), the Belmont Forum, the National Aeronautics 622 and Space Administration (grant no. NNX14AD31G), and National Geographic Society (grant no. 8763-10); S.G.A.F. by Trond Mohn Stiftelse (TMS) and University of Bergen (Grant No. TMS2022STG03/Past, Present and Future of Alpine Biomes Worldwide); H.H. by the Netherlands Organization for Tropical Research (grant WB 84-636) to study Lake La Cocha; S.Y.M. and W.D.G. by the European Commission (Marie Curie Fellowship 792197); C.N.H.M. by the European Research Council Starting Grant StG 853394 (2019) and the NWO-ALWOP.322; E.M. by the Natural Environment Research Council (NERC) of UK (grant NE/J018562/1), and for radiocarbon dating by the NERC Radiocarbon Facility NRCF010001 (allocation number 1682.1112); M.d.N.N. by the National Science Foundation (NSF)âDEB 1260983, EAR 1338694 and 1624207. All work for Lake Kumpaka was conducted under Ecuadorian Collection Permit 08-620 2017-IC and for Lake Pindo under Permit 14-2012-IC-FLO-DPAP-MA
Vitamin d plasma levels and in-hospital and 1-year outcomes in acute coronary syndromes : a prospective study
Deficiency in 25-hydroxyvitamin D (25[OH]D), the main circulating form of vitamin D in blood, could be involved in the pathogenesis of acute coronary syndromes (ACS). To date, however, the possible prognostic relevance of 25 (OH)D deficiency in ACS patients remains poorly defined. The purpose of this prospective study was to assess the association between 25 (OH)D levels, at hospital admission, with in-hospital and 1-year morbidity and mortality in an unselected cohort of ACS patients.We measured 25 (OH)D in 814 ACS patients at hospital presentation. Vitamin D serum levels >30\u200ang/mL were considered as normal; levels between 29 and 21\u200ang/mL were classified as insufficiency, and levels\u200a<\u200a20\u200ang/mL as deficiency. In-hospital and 1-year outcomes were evaluated according to 25 (OH)D level quartiles, using the lowest quartile as a reference.Ninety-three (11%) patients had normal 25 (OH)D levels, whereas 155 (19%) and 566 (70%) had vitamin D insufficiency and deficiency, respectively. The median 25 (OH)D level was similar in ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) patients (14.1 [IQR 9.0-21.9] ng/mL and 14.05 [IQR 9.1-22.05] ng/mL, respectively; P\u200a=\u200a.88). The lowest quartile of 25 (OH)D was associated with a higher risk for several in-hospital complications, including mortality. At a median follow-up of 366 (IQR 364-379) days, the lowest quartile of 25 (OH)D, after adjustment for the main confounding factors, remained significantly associated to 1-year mortality (P\u200a<\u200a.01). Similar results were obtained when STEMI and NSTEMI patients were considered separately.In ACS patients, severe vitamin D deficiency is independently associated with poor in-hospital and 1-year outcomes. Whether low vitamin D levels represent a risk marker or a risk factor in ACS remains to be elucidated
- âŚ