Biomedical subjects

Yu Xiang

Publications and source records attributed to Yu Xiang.

7 recordsLinked to original sources

PubMed2026

Effects of intensive blood pressure control on cardio-kidney outcomes by KDIGO risk categories: a Post Hoc analysis of ACCORD-BP and SPRINT trials.

The effects of intensive systolic blood pressure (SBP) control on cardiovascular (CV) and kidney outcomes across different Kidney Disease Improving Global Outcomes (KDIGO) risk categories remain unclear. We performed a secondary analysis of the Systolic Blood Pressure Intervention Trial (SPRINT) and the SPRINT-eligible Action to Control Cardiovascular Risk in Diabetes Blood Pressure (ACCORD-BP) trial. Participants were categorized into low, moderate, and high/very-high KDIGO risk groups. The primary outcomes were composite adverse CV events (defined as nonfatal myocardial infarction (MI), nonfatal stroke, fatal or hospitalized heart failure (HF), and CV mortality) and composite adverse kidney events (defined as a sustained decline in eGFR of ≥ 40% and end-stage kidney disease (ESKD)). We found that intensive BP control reduced the risk of composite CV events (HR 0.68; 95% CI 0.59-0.78), with attenuated benefits in higher KDIGO risk categories (P for interaction = 0.055). This interaction was mainly driven by nonfatal MI and fatal or hospitalized HF (both P for interaction < 0.05). Intensive BP control increased the risk of composite kidney events (HR 1.88; 95% CI 1.52-2.33), mainly in low- and moderate-risk groups rather than in high/very-high risk groups (P for interaction = 0.04). Similar patterns were observed for sustained eGFR decline (P for interaction = 0.03), but not for ESKD (HR 1.05; 95% CI 0.74-1.48; P for interaction = 0.71). The KDIGO risk classification modified the effects of intensive BP control. Balancing CV benefits against potential kidney impacts in patients with different KDIGO risks during intensive BP treatment is recommended. Trial Registration: ClinicalTrials.gov Identifiers: NCT01206062 (SPRINT) and NCT00000620 (ACCORD).

Cardiovascular outcome↗

PubMed2024

BRCA1 safeguards genome integrity by activating chromosome asynapsis checkpoint to eliminate recombination-defective oocytes.

In the meiotic prophase, programmed DNA double-strand breaks are repaired by meiotic recombination. Recombination-defective meiocytes are eliminated to preserve genome integrity in gametes. BRCA1 is a critical protein in somatic homologous recombination, but studies have suggested that BRCA1 is dispensable for meiotic recombination. Here we show that BRCA1 is essential for meiotic recombination. Interestingly, BRCA1 also has a function in eliminating recombination-defective oocytes. Brca1 knockout (KO) rescues the survival of Dmc1 KO oocytes far more efficiently than removing CHK2, a vital component of the DNA damage checkpoint in oocytes. Mechanistically, BRCA1 activates chromosome asynapsis checkpoint by promoting ATR activity at unsynapsed chromosome axes in Dmc1 KO oocytes. Moreover, Brca1 KO also rescues the survival of asynaptic Spo11 KO oocytes. Collectively, our study not only unveils an unappreciated role of chromosome asynapsis in eliminating recombination-defective oocytes but also reveals the dual functions of BRCA1 in safeguarding oocyte genome integrity.

Oocytes↗

PubMed2006

New fluorescent rhodamine hydrazone chemosensor for Cu(II) with high selectivity and sensitivity.

[reaction: see text] A new fluorescent probe, salicylaldehyde rhodamine B hydrazone (1), was synthesized and displayed selective Cu(II)-amplified absorbance and fluorescence emission above 500 nm in neutral buffered media. Upon the addition of Cu(II), the spirolactam ring of 1 was opened and a 1:1 metal-ligand complex was formed. The detection of Cu(II) by 1 at a lower micromolar level was successful even in buffered water.

Copper↗

PubMed2006

A new rhodamine-based chemosensor exhibiting selective Fe(III)-amplified fluorescence.

[structure: see text] A new fluorescent probe 3 was synthesized, and it exhibited high selectivity for Fe(III) over other commonly coexistent metal ions in both ethanol and water. Upon the addition of Fe(III), the spirocyclic ring of 3 was opened and a significant enhancement of visible color and fluorescence in the range of 500-600 nm was observed.

Journal Article↗

PubMed2006

A 38-amino-acid sequence encompassing the arm domain of the cucumber necrosis virus coat protein functions as a chloroplast transit Peptide in infected plants.

Experiments to determine the subcellular location of the coat protein (CP) of the tombusvirus Cucumber necrosis virus (CNV) have been conducted. By confocal microscopy, it was found that an agroinfiltrated CNV CP-green fluorescent protein (GFP) fusion targets chloroplasts in Nicotiana benthamiana leaves and that a 38-amino-acid (aa) region that includes the complete CP arm region plus the first 4 amino acids of the shell domain are sufficient for targeting. Western blot analyses of purified and fractionated chloroplasts showed that the 38-aa region directs import to the chloroplast stroma, suggesting that the CNV arm can function as a chloroplast transit peptide (TP) in plants. Several features of the 38-aa region are similar to features typical of chloroplast TPs, including (i) the presence of an alanine-rich uncharged region near the N terminus, followed by a short region rich in basic amino acids; (ii) a conserved chloroplast TP phosphorylation motif; (iii) the requirement that the CNV 38-aa sequence be present at the amino terminus of the imported protein; and (iv) specific proteolytic cleavage upon import into the chloroplast stroma. In addition, a region just downstream of the 38-aa sequence contains a 14-3-3 binding motif, suggesting that chloroplast targeting requires 14-3-3 binding, as has been suggested for cellular proteins that are targeted to chloroplasts. Chloroplasts of CNV-infected plants were found to contain CNV CP, but only the shell and protruding domain regions were present, indicating that CNV CP enters chloroplasts during infection and that proteolytic cleavage occurs as predicted from agroinfiltration studies. We also found that particles of a CNV CP mutant deficient in externalization of the arm region have a reduced ability to establish infection. The potential biological significance of these findings is discussed.

Amino Acid Sequence↗

PubMed2003

Complex magnetohydrodynamic low-Reynolds-number flows.

The interaction between electric currents and a magnetic field is used to produce body (Lorentz) forces in electrolyte solutions. By appropriate patterning of the electrodes, one can conveniently control the direction and magnitude of the electric currents and induce spatially and temporally complicated flow patterns. This capability is useful, not only for fundamental flow studies, but also for inducing fluid flow and stirring in minute devices in which the incorporation of moving components may be difficult. This paper focuses on a theoretical and experimental study of magnetohydrodynamic flows in a conduit with a rectangular cross section. The conduit is equipped with individually controlled electrodes uniformly spaced at a pitch L. The electrodes are aligned transversely to the conduit's axis. The entire device is subjected to a uniform magnetic field. The electrodes are divided into two groups A and C in such a way that there is an electrode of group C between any two electrodes of group A. We denote the various A and C electrodes with subscripts, i.e., A(i) and C(i), where i=0,+/-1,+/-2, .... When positive and negative potentials are, respectively, applied to the even and odd numbered A electrodes, opposing electric currents are induced on the right and left hand sides of each A electrode. These currents generate transverse forces that drive cellular convection in the conduit. We refer to the resulting flow pattern as A. When electrodes of group C are activated, a similar flow pattern results, albeit shifted in space. We refer to this flow pattern as C. By alternating periodically between patterns A and C, one induces Lagrangian chaos. Such chaotic advection may be beneficial for stirring fluids, particularly in microfluidic devices. Since the flow patterns A and C are shifted in space, they also provide a mechanism for Lagrangian drift that allows net migration of passive tracers along the conduit's length.

Journal Article↗

PubMed2001

Genomic organization of RNA2 of Tomato ringspot virus: processing at a third cleavage site in the N-terminal region of the polyprotein in vitro.

The proteinase of Tomato ringspot virus (genus Nepovirus) is responsible for proteolytic cleavage of the RNA2-encoded polyprotein (P2) at two cleavage sites, allowing definition of the domains for the movement protein (MP) and coat protein. In this study, we have characterized a third cleavage site in the N-terminal region of P2 using an in vitro processing assay and partial cDNA clones. Results from site-directed mutagenesis of putative cleavage sites suggest that cleavage occurs at dipeptide Q(301)/G. Cleavage at this site is predicted to result in the release of two proteins from the N-terminal region of P2: a 34 kDa protein located at the N terminus of P2 (assuming translation initiation at the first AUG codon) and a 71 kDa protein located immediately upstream of the MP domain. In contrast, only one protein domain is present in the equivalent region of the P2 polyprotein of other characterized nepoviruses.

Binding Sites↗