Biomedical subjects

Jin Yu

Publications and source records attributed to Jin Yu.

51 records · Page 3Linked to original sources

PubMed2004

[Study on the time selection of pregnancy and delivery in women with systemic lupus erythematosus].

OBJECTIVE: To analyze the appropriate time selection of pregnancy and delivery in women with systemic lupus erythematosus (SLE). METHODS: Twenty-nine pregnancies in women with SLE in our hospital from 1998 to 2003 were retrospectively analyzed regarding the selection of appropriate time of pregnancy and delivery. RESULTS: All patients did not take any cytotoxic medicine for at least 6 months before pregnancy. Twenty-three conceptions occurred when SLE was inactive for at least 1 year. Two conceptions occurred when SLE was active without doctors' agreement. SLE was diagnosed during pregnancy in the remaining 4 cases. The condition of all patients fluctuated and the gestational time at delivery ranged from 30 to 38 weeks after we modified the doses of glucocorticoid (prednisone). Among totally 29 living neonates, eight were premature neonates, three were FGR and one had serious congenital heart disease. Two neonates died of complications in early stage of neonatal period. None of the 29 neonates from all patients had neonatal lupus. CONCLUSION: Pregnancy safety will be improved obviously if the condition of SLE is controlled and the patients are given reasonable doses of glucocorticoid and intensive monitoring. If pharmacotherapy does not work well and the condition threatens the safety of mother and fetus, or the fetus has matured, termination of pregnancy should be done on time, which reduces maternal complications and improves the perinatal mortality rate. The gestational time should be 34 to 38 weeks.

Delivery, Obstetric↗

PubMed2004

[Application of molecular biology techniques in the identification of pathogenic fungi and the diagnosis of fungal infection].

With the increasing incidence and mortality of fungal infection, the requirements for strict diagnostic approaches became a very urgent issue. Because of the traditional detective techniques, such as culture, gave poor diagnostic outcomes, the molecular biological techniques are expected to develop the potential diagnostic approaches. During the past decades, we have carried out serial studies on the molecular properties of pathogenic fungi, and we would like to review as following. Firstly, we applied several molecular tools in classification and identification of pathogenic fungi. We performed random amplification of polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) and other techniques in studying the typing, to classify and identify the properties of Dermatophytes, Candida spp., Cryptococcus neoformans, Dematiaceous fungi, and Aspergillus spp. Interestingly, we found the same T. rubrum strain might infect different sites of the host, while a site-specificity displayed in T. mentagrophytes. This finding indicated the genetic discrepancies among the fungi. Beside, we also found that the E. dermatitis strains with different virulences possessed some discrepancies at gene level. We then developed a PCR-based molecular procedure to identify the novel species in Exophiala spp. As the applicable strategy, we also investigated the rDNA sequence properties in several fungi. And as a result, we submitted for the first time to GenBank the complete sequence of Aspergillus fumigatus rDNA/ITSI/ITSII, which provided the basis for designing the species-specific probes and for its further clinical applications. Secondly, we have tried to develop the molecular diagnostic approaches based on our DNA sequence data which were used for identification studies previously. By analyzing the DNA sequence of Aspergillus fumigatus rDNA/ITSI/ITSII, we developed a nested PCR method to detect Aspergillus fumigatus genes. Our preliminary results indicated that this PCR-based molecular approach has great importance in the diagnosis of invasive aspergillosis. We also designed the species-specific probes and then established several in situ hybridization procedures. We found these hybridization methods could get the positive rate up to 81% (13/16), which suggests that these methods have potential diagnostic value for invasive candidiasis and aspergillosis. Based on our experiences, we would conclude that the molecular biological techniques possess great value to investigate the biological properties of pathogenic fungi, and we are looking forward to see more and more molecular tools will be used in the pathogenic mechanisms of fungal infections and antifungal activity studies.

Aspergillosis↗

PubMed2004

Influence of N,N'-diacetyl-L-cystine on D-galactosamine/lipopolysaccharide induced immunological liver failure in mice.

AIM: To study the therapeutic effects of N,N'-diacetyl-L-cystine (DiNAC) on immunological liver failure. METHODS: Serum ALT, AST and T cell subsets in peripheral blood of the experimental animals during the trial period were analyzed by an automatic serum analyzer and a flow cytometer, respectively. The sectioned liver specimens were examined under a light microscope. And 24 h after the injection of Gal/LPS, the survival rate of rats was calculated. RESULTS: DiNAC (50, 200, 800 mg x kg(-1), i.p.) suppressed the elevation of serum levels of ALT and AST, markedly enhanced proliferation and differentiation of T cell subsets (CD4+, CD8+ and Th1, Th2), and improved all the histopathological features. In mice of fulminant hepatic failure (FHF), the survival time significantly prolonged and the survival rate increased 24 h after i.p. DiNAC. These effects were obviously dose-dependent. CONCLUSION: DiNAC on mice with FHF has an inhibitory action which is related to immune mechanism.

Alanine Transaminase↗

PubMed2003

Sonographic probing of laser filaments in air.

The acoustic wave emitted from the plasma channel associated with a filament induced by a femtosecond laser pulse in air was detected with a microphone. This sonographic detection provides a new method to determine the length and the spatial profile of the free-electron density of a filament. The acoustic wave is emitted owing to the expansion of the gas in the filament, which is heated through collisions with high-energy photoelectrons generated by multiphoton ionization. Compared with other methods, the acoustic detection is simpler, more sensitive, and with higher spatial resolution, making it suitable for field measurements over kilometer-range distances or laboratory-scale studies on the fine structure of a filament.

Journal Article↗

PubMed2003

In vitro and in vivo modulations of benzo[c]phenanthrene-DNA adducts by DNA mismatch repair system.

Benzo[c]phenanthrene dihydrodiol epoxide (B[c] PhDE) is well known as an important environmental chemical carcinogen that preferentially modifies DNA in adenine residues. However, the molecular mechanism by which B[c]PhDE induces tumorigenesis is not fully understood. In this report, we demonstrate that DNA mismatch repair (MMR), a genome maintenance system, plays an important role in B[c]PhDE-induced carcinogensis by promoting apoptosis in cells treated with B[c]PhDE. We show that purified human MMR recognition proteins, MutS(alpha) and MutSbeta, specifically recognized B[c]PhDE-DNA adducts. Cell lines proficient in MMR exhibited several-fold more sensitivity to killing than cell lines defective in either MutS(alpha) or MutL(alpha) by B[c]PhDE; the nature of this sensitivity was shown to be due to increased apoptosis. Additionally, wild-type mice exposed to B[c]PhDE had intestinal crypt cells that underwent apoptosis significantly more often than intestinal crypt cells found in B[c]PhDE-treated Msh2(-/-) or Mlh1(-/-) mice. These findings, combined with previous studies, suggest that the MMR system may serve as a general sensor for chemical-caused DNA damage to prevent damaged cells from mutagenesis and carcinogenesis by promoting apoptosis.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Red solitons: evidence of spatiotemporal instability in chi 2 spatial soliton dynamics.

In chi(2) three-wave mixing, the noise-seeded spatiotemporal modulational instability has a dramatic impact on the spatial soliton formation and on their stability, leading to the occurrence of a temporal breakup on the 20 fs scale and to the counterintuitive observation of spatial solitons with no apparent participation of the high-frequency field in the self-trapping.

Journal Article↗

PubMed2003

Fibroblast growth factor-18 reduced infarct volumes and behavioral deficits after transient occlusion of the middle cerebral artery in rats.

BACKGROUND AND PURPOSE: Fibroblast growth factor 18 (FGF18) is expressed in rodent brain and is a trophic factor for neuron-derived cells in culture. The purpose of the present study was to evaluate whether FGF18 was neuroprotective in a rat model of cerebral ischemia and to compare the results with those obtained with FGF2. METHODS: Cerebral ischemia was produced in rats by a transient 2-hour occlusion of the middle cerebral artery (MCAo) with an intraluminal filament followed by 22-hour reperfusion. Starting 15 minutes after MCAo, FGF18 or FGF2 was administered by a 3-hour intravenous infusion. Infarct volumes and behavioral deficits were measured 24 hours after MCAo. RESULTS: Infusion of FGF18 produced dose-dependent reductions in infarct volumes and improvements in tests of reference and working memory, motor ability, and exploratory behavior. FGF18 was more efficacious than FGF2 on virtually all measures examined. The reductions in infarct volume and behavioral deficit were associated with FGF-mediated increases in regional cerebral blood flow. CONCLUSIONS: These results demonstrate that FGF18 is an effective neuroprotective agent in a rat model of transient MCAo.

Animals↗

PubMed2003

RAGE mediates amyloid-beta peptide transport across the blood-brain barrier and accumulation in brain.

Amyloid-beta peptide (Abeta) interacts with the vasculature to influence Abeta levels in the brain and cerebral blood flow, providing a means of amplifying the Abeta-induced cellular stress underlying neuronal dysfunction and dementia. Systemic Abeta infusion and studies in genetically manipulated mice show that Abeta interaction with receptor for advanced glycation end products (RAGE)-bearing cells in the vessel wall results in transport of Abeta across the blood-brain barrier (BBB) and expression of proinflammatory cytokines and endothelin-1 (ET-1), the latter mediating Abeta-induced vasoconstriction. Inhibition of RAGE-ligand interaction suppresses accumulation of Abeta in brain parenchyma in a mouse transgenic model. These findings suggest that vascular RAGE is a target for inhibiting pathogenic consequences of Abeta-vascular interactions, including development of cerebral amyloidosis.

Aged↗

PubMed2002

Inflammation-dependent cerebral deposition of serum amyloid a protein in a mouse model of amyloidosis.

The major pathological hallmark of amyloid diseases is the presence of extracellular amyloid deposits. Serum amyloid A (SAA) is an apolipoprotein primarily produced in the liver. Serum protein levels can increase one thousandfold after inflammation. SAA is the precursor to the amyloid A protein found in deposits of systemic amyloid A amyloid (AA or reactive amyloid) in both mouse and human. To study the factors necessary for cerebral amyloid formation, we have created a transgenic mouse that expresses the amyloidogenic mouse Saa1 protein in the brain. Using the synapsin promoter to drive expression of the Saa1 gene, the brains of transgenic mice expressed both RNA and protein. Under noninflammatory conditions, transgenic mice do not develop AA amyloid deposits in the brain; however, induction of a systemic acute-phase response in transgenic mice enhanced amyloid deposition. This deposition was preceded by an increase in cytokine levels in the brain, suggesting that systemic inflammation may be a contributing factor to the development of cerebral amyloid. The nonsteroidal anti-inflammatory agent indomethacin reduced inflammation and protected against the deposition of AA amyloid in the brain. These studies indicate that inflammation plays an important role in the process of amyloid deposition, and inhibition of inflammatory cascades may attenuate amyloidogenic processes, such as Alzheimer's disease.

Age Factors↗

PubMed2002

White-light nanosource with directional emission.

We report the first observation of white-light emission from femtosecond laser-induced plasma in a water droplet. Such emission is not observed with water in a cell. The microdroplet acts as a lens, focusing the incident light to nanosized regions within itself and directing the emission from these regions primarily back toward the laser source. This focusing increases the intensity so that multiphoton ionization generates plasma and causes it to reach the critical density during the initial part of the pulse, enabling the rest of the pulse to heat the plasma enough to emit in the visible.

Journal Article↗

PubMed2002

Identification of differentially expressed genes in human uterine leiomyomas using differential display.

UNLABELLED: In searching of differentially expressed genes in human uterine leiomyomas, differential display was used with twelve pairs of primers to compare human uterine leiomyomas with matched myometrium. False positives were eliminated by reverse Northern analysis. Positives were confirmed by Northern blot analysis. RESULTS: Four of 69 cDNA fragments (3 up-regulated named L1, L2 and L3 and 1 down-regulated named M1 in leiomyoma) were confirmed by Northern analysis. Sequence comparison and Northern analysis proved that L1 is exactly the human ribosomal protein S19. It was present ubiquitously in 13 tissues tested but in various levels and even in different size. L1 was highly expressed in parotidean cystadenocarcinoma, pancreatic cancer and breast cancer examined. No mutations have been found in human uterine leiomyomas (n=6). CONCLUSIONS: hRPS19 overexpression might be a universal signal in rapid cell growth tissues.

DNA, Complementary↗

PubMed2002

Overexpression of SR-BI by adenoviral vector promotes clearance of apoA-I, but not apoB, in human apoB transgenic mice.

Scavenger receptor BI (SR-BI) is a multi-ligand lipoprotein receptor that mediates selective lipid uptake from HDL, and plays a central role in hepatic HDL metabolism. In this report, we investigated the extent to which SR-BI selective lipid uptake contributes to LDL metabolism. As has been reported for human LDL, mouse SR-BI expressed in transfected cells mediated selective lipid uptake from mouse LDL. However, LDL-cholesteryl oleoyl ester (CE) transfer relative to LDL-CE bound to the cell surface (fractional transfer) was approximately 18-fold lower compared with HDL-CE. Adenoviral vector-mediated SR-BI overexpression in livers of human apoB transgenic mice ( approximately 10-fold increased expression) reduced plasma HDL-cholesterol (HDL-C) and apolipoprotein (apo)A-I concentrations to nearly undetectable levels 3 days after adenovirus infusion. Increased hepatic SR-BI expression resulted in only a modest depletion in LDL-C that was restricted to large LDL particles, and no change in steady-state concentrations of human apoB. Kinetic studies showed a 19% increase in the clearance rate of LDL-CE in mice with increased SR-BI expression, but no change in LDL apolipoprotein clearance. Quantification of hepatic uptake of LDL-CE and LDL-apolipoprotein showed selective uptake of LDL-CE in livers of human apo B transgenic mice. However, such uptake was not significantly increased in mice over-expressing SR-BI. We conclude that SR-BI-mediated selective uptake from LDL plays a minor role in LDL metabolism in vivo.

Adenoviridae↗

PubMed2002

The fate of HDL particles in vivo after SR-BI-mediated selective lipid uptake.

Scavenger receptor class B type I (SR-BI) delivers cholesterol ester from HDL to cells via a selective uptake mechanism, whereby lipid is transferred from the core of the particle without concomitant degradation of the protein moiety. The precise metabolic fate of HDL particles after selective lipid uptake is not known. To characterize SR-BI-mediated HDL processing in vivo, we expressed high levels of this receptor in livers of apoA-I(-/-) mice by adenoviral vector gene transfer, and then injected the mice with a bolus of human HDL(2) traced with (125)I-dilactitol tyramine. HDL recovered from apoA-I(-/-) mice over-expressing SR-BI was significantly smaller than HDL recovered from control mice as measured by non-denaturing gel electrophoresis. When injected into C57BL/6 mice, these HDL "remnants" were rapidly converted to HDL(2)-sized lipoprotein particles, and were cleared from the plasma at a rate similar to HDL(2). In assays in cultured cells, HDL remnants did not stimulate ATP-binding cassette transporter A1-dependent cholesterol efflux. When mixed with mouse plasma ex vivo, HDL remnants rapidly converted to larger HDL particles. These studies identify a previously ill-defined pathway in HDL metabolism, whereby SR-BI generates small, dense HDL particles that are rapidly remodeled in plasma. This remodeling pathway may represent a process that is important in determining the rate of apoA-I catabolism and HDL-mediated reverse cholesterol transport.

ATP Binding Cassette Transporter 1↗

PubMed2002

Mycotic aneurysm of thoracic aorta with aortoesophageal fistula mimicking the esophageal tumor with bleeding--a case report.

An aortoesophageal fistula is a rare but fatal disease, most commonly associated with thoracic aortic aneurysm. Early diagnosis and emergency surgical intervention are mandatory for survival. We reported a case of mycotic aneurysm of thoracic aorta with aortoesophageal fistula, presenting with intermittent hematemesis, tarry stool and sepsis. Initially, misdiagnosis of esophageal submucosal tumor with bleeding was made clinically and endoscopically. With contrast-enhanced spiral computed tomography (CT) scan the diagnosis was confirmed. The pathogenesis, clinical presentation, endoscopic feature and imaging findings were reviewed.

Aged↗

PubMed1999

Apolipoprotein Serum Amyloid A in Alzheimer's Disease.

Alzheimer's disease is characterized by the tissue deposition of beta-amyloid peptide (Abeta) in the brain. Recent studies have shown apoproteins (apo) in amyloid plaques and associated with high-density lipoprotein (HDL) particles in the cerebrospinal fluid (CSF). Western blot analysis revealed that serum amyloid A (apoSAA) protein was present in control and AD patients at low levels compared to apoE and apoA-I, however, AD brains showed a significant increase over control values. Analysis of CSF-HDL from control and AD individuals showed that apoA-I, apoE and apoSAA were on the particle. Immuno-cytochemical analysis showed that SAA was detected in senile plaques in AD tissue, but was predominantly localized to neuritic plaques. ApoE staining of AD brain confirmed that most plaques contained the apoprotein, similar to Abeta immunoreactivity, whereas apoA-I expressed little staining of senile plaques. No significant differences were detected in the level of apoSAA when compared to APOE genotype in AD samples, suggesting that interactions with apoE were non-specific. These data imply that the specific interactions of SAA with Abeta in the neuritic plaques may play a role in AD.

Journal Article↗