Biomedical subjects

W Yin

Publications and source records attributed to W Yin.

At least 19 recordsLinked to original sources

PubMed2006

The fragmentation mechanism of beta-(N-alkyl/arylamino)-alpha,beta-unsaturated carboxylates under electrospray ionization conditions.

The positive ion mass spectrometric behavior of six beta-(N-alkyl/arylamino)-alpha,beta-unsaturated carboxylates, alpha-(1-alkyl/arylaminoethylidene)-gamma-lactones, has been studied under electrospray ionization conditions. Their fragmentation pathways are described and supported by tandem mass spectrometry. The protonated compounds are apt to eliminate a water, and a water plus a oxacyclopent-2-yne molecule. Some of the compounds show a tendency to undergo a four-membered ring contraction rearrangement to lose a carbon dioxide. The fragmentation patterns of these compounds exhibit a strong substituent dependency.

Carboxylic Acids↗

PubMed2006

Co-resistance to retinoic acid and TRAIL by insertion mutagenesis into RAM.

Retinoic acid (RA), used as first-line therapy for acute promyelocytic leukemia (APL), exerts its antileukemic activity by inducing blast differentiation and activating tumor-selective TNF-related apoptosis-inducing ligand (TRAIL) signaling. To identify downstream mediators of RA signaling, we used retrovirus-mediated insertion mutagenesis in PLB985 leukemia cells and established the RA-resistant cell line WY-1. In PLB985, but not WY-1 cells, RA induced TRAIL and its DR4 and DR5 receptors. Knocking down TRAIL expression by RNA interference blocked RA-induced apoptosis. WY-1 cells are defective for RA-induced differentiation, G1 arrest and exhibit co-resistance to TRAIL. In WY-1 cells, a single virus copy is integrated into a novel RA-regulated gene termed RAM (retinoic acid modulator). RAM is expressed in the myelomonocytic lineage and extinguished by RA in PLB985, but not WY-1 cells. Whereas knocking down RAM expression by RNA interference promoted RA-induced differentiation and TRAIL-triggered apoptosis of PLB985 and WY-1 cells, overexpression of the predicted 109 amino-acid RAM open reading frame did not alter RA signaling in PLB985 cells. This indicates that, apart from encoding the putative RAM protein, RAM RNA may exert additional functions that are impaired by the retrovirus insertion. Our study demonstrates that RA induction of the TRAIL pathway is also operative in leukemia cells lacking an RARalpha oncofusion protein and identifies RAM as a novel RA-dependent modulator of myeloid differentiation and death.

Amino Acid Sequence↗

PubMed2006

Blood platelets activate the classical pathway of human complement.

OBJECTIVE: Activation of the complement system plays a key role in inflammation associated with vascular injury. Recently, platelet P-selectin was shown to activate C3 via the alternative pathway of human complement. As platelets also posses binding sites for C1q, the recognition unit of the classical complement pathway, the present study examined classical pathway activation on platelets. METHODS: Complement activation was assessed by either a solid phase enzyme-linked immunosorbent assay (ELISA) or flow cytometry. RESULTS: Using the ELISA approach, 2- to 10-fold increases (P < 0.001) in C1q and C4d deposition were demonstrated on adherent platelets following exposure (60 min 37 degrees C) to diluted (1/10) human plasma or serum. Similar results were obtained by flow cytometry using activated platelets in suspension. C1q and C4d deposition on platelets was accompanied by an approximately 4-fold increase in fluid phase C4d and C3a generation. Consistent with activation of the classical complement pathway, C4 cleavage failed to occur in serum depleted of C1q but was unchanged in factor B deficient serum. C4 activation was enhanced by platelet stimulation using chemical (SFLLRN peptide) or mechanical (shear) means, and decreased following platelet exposure to plasmin. These treatments were accompanied by changes in platelet surface gC1qR/p33 expression, a cellular C1q binding protein. In purified systems, recombinant gC1qR/p33 supported C4 activation, in a C1q dependent manner. CONCLUSION: These data provide the first evidence for C1q dependent classical complement pathway activation on platelets, and support a role for gC1qR/p33 in this process. However, monoclonal antibodies (mAb) to gC1qR/p33 produced only modest (20% +/- 8%, mean +/- SD, n = 5) reductions in C4 activation on platelets. Thus, further studies are required to investigate the involvement of additional platelet membrane constituents in classical complement pathway activation.

Blood Platelets↗

PubMed2004

Therapeutic drug monitoring of tacrolimus in early stage after heart transplantation.

INTRODUCTION: Little is known about the pharmacokinetic (PK) profiles of tacrolimus (Tac) within the first week after heart transplantation (HT) in adults. Our objective was to investigate the PK profiles of Tac in early after HT. METHODS: Twenty-three adult HT patients received Tac as primary immunosuppression. Tac was administered orally at a starting dosage of 0.10 mg/kg/d. The Tac dosages were adjusted to a target range of 10 to 20 ng/mL during the first 1 month after HT. The PK profiles were analyzed immediately after the first dose (PK1; n = 14), at day 3 (PK2; n = 10), and at day 7 (PK3; n = 8) to assess the relationships between PK parameters and acute rejection rates. RESULTS: The correlation between Tac trough levels and Tac-AUCs were r = .95 PK1; r = .82, PK2; and r = .88, PK3. When AUC(0-12h) was controlled in the range from 150 to 300 ng x h/mL (10 to 20 ng/mL trough levels), 17 of 18 patients (94.4%) did not show evidence of significant rejection (72.2% grade 0, 16.7% 1A, and 5.5% grade 1B). One patient displayed a grade 2 biopsy score (5.5%). Mean AUC(0-12h) values of Tac were significantly lower among patients who experienced acute rejection than those who remained rejection-free (89 vs 217 ng x h/mL, P = .023). CONCLUSION: The initial trough levels are good indicators of systemic exposure. To reduce the risk of rejection and renal toxicity, the trough levels should be controlled in range from 10 to 20 ng/mL in early stage after HT.

Adolescent↗

PubMed2004

NO-1886 decreases ectopic lipid deposition and protects pancreatic beta cells in diet-induced diabetic swine.

The synthetic compound NO-1886 (ibrolipim) is a lipoprotein lipase activator that has been proven to be highly effective in lowering plasma triglycerides. Recently, we found that NO-1886 also reduced plasma free fatty acids and glucose in high-fat/high-sucrose diet-induced diabetic rabbits. In the current study, we investigated the effects of NO-1886 treatment on ectopic lipid deposition and the islet pathology in miniature swine fed a high-fat/high-sucrose diet. Our results showed that feeding this diet to miniature swine caused insulin resistance, increased lipid deposition in non-adipose tissue, such as in the heart, skeletal muscle, liver and pancreas, and also caused pancreatic beta cell damage. However, supplementing 1% NO-1886 (200 mg/kg per day) into the high-fat/high-sucrose diet decreased ectopic lipid deposition, improved insulin resistance, and alleviated the beta cell damage. These results suggest that improvement of lipid disorder, non-adipose tissue steatosis and insulin resistance may be very important for the protection of beta cell damage. Therefore, NO-1886 is potentially beneficial for the treatment of insulin-resistance syndrome.

Animals↗

PubMed2003

Stimulation of Na,K-ATPase by low potassium is dependent on transferrin.

We took advantage of the fact that confluent MDCK cells can survive in a serum-free medium for several days to examine whether the upregulation of Na,K-ATPase by low K+ required serum. We found that serum was essential for low K+ to induce an increase in the cell surface Na,K-ATPase molecular number as quantified by ouabain binding assays. Further analyses identified that transferrin, not EGF or IGF-1, could simulate the effect of serum. Moreover, transferrin was also required for low-K(+)-induced increases in al-subunit promoter activity, al- and el-subunit protein abundance of the Na,K-ATPase. In the presence of transferrin, low K+ enhanced cellular uptake of iron. Inhibition of intracellular iron activity by deferoxamine (40 microM) abrogated the effect of low K+ on the Na,K-ATPase. Like deferoxamine, catalase (100 U/ml) also ablated the effect of low K+. We conclude that stimulation of the Na,K-ATPase by low K+ is dependent on transferrin. The effect of transferrin is mediated by increased iron transport and reactive oxygen species activity.

Animals↗

PubMed2002

Metabolic alterations in cerebrospinal fluid from double hemorrhage model of dogs.

OBJECTIVE: Even though cerebral vasospasm after subarachnoid hemorrhage (SAH) causes cerebral ischemia or infarction, the metabolic alterations in cerebrospinal fluids (CSF) after SAH have not been studied. This study was undertaken to measure the levels of glucose, lactate, pyruvate and glutamate in CSF from double hemorrhage dog models. METHOD: Thirty-two mongrel dogs of either sex, weighing 15-30 kg, underwent double hemorrhage by percutaneous needle puncture of the cisterna magna and injection of autologous blood on day 0 and day 2. The dogs were then sacrificed on day 3, 5 and 7, after collecting CSF. In another study, the dogs were treated with mitogen-activated protein kinase (MAPK) inhibitors PD98059 and U0126, and caspase-2 and caspase-3 inhibitors from day 3 to day 6 after initial blood injection. CSF was collected on day 7 before dogs were sacrificed. The concentration of glucose, lactate, pyruvate and glutamate in CSF was measured by photometrical method. RESULTS: Compared with CSF collected on day 0, glucose was decreased on days 5-7, lactate was increased on days 2-7, pyruvate was increased on days 2-7, and glutamate was increased on days 3-7 (P < 0.05). In the groups treated with MAPK or caspase inhibitors, most of the metabolic alterations remained unchanged as compared with CSF from untreated dogs. Clinically, caspase inhibitors-2 and -3, and MAPK inhibitor U0126 all failed to prevent vasospasm. MAPK inhibitor PD98059 partially prevented vasospasm. CONCLUSION: Our data demonstrated a metabolic alteration of glucose, glutamate, lactate and pyruvate in CSF during cerebral vasospasm. This metabolic change is consistent with the time course of cerebral vasospasm. This study suggests that brain energy metabolites and excitative amino acids are altered during cerebral vasospasm.

Analysis of Variance↗

PubMed2002

Haemoglobin and ATP levels in CSF from a dog model of vasospasm.

Haemoglobin and adenosine 5'-triposphate (ATP) released from lysed erythrocytes have been postulated to be responsible for delayed cerebral vasospasm after subarachnoid haemorrhage (SAH). However, the concentrations of haemoglobin and ATP in cerebrospinal fluid (CSF) in patients or in an animal model of vasospasm have not been reported. In this study, 12 mongrel dogs underwent a double blood injection via the cisterna magna on day 0 and 2, after an initial collection of CSF. On day 3, 5 or 7, the dogs were sacrificed after a second collection of CSF. An angiogram was recorded on day 0 and on the day of sacrifice. Results showed that the diameter of the dog's basilar artery was reduced 20% on day 3 (P > 0.05), 35% on day 5 (P < 0.05) and 45% on day 7 (P < 0.05). The concentrations of OxyHb, deOxyHb and MetHb in CSF were increased (P < 0.05), and all peaked on day 3. OxyHb and MetHb remained significantly higher than control (day 0) from day 3 to day 7, while deOxyHb remained at a high level on day 5 but returned to normal on day 7. In contrast, ATP was decreased (P < 0.05) on days 5 and 7 after SAH compared with day 0. The results indicate that haemoglobin might be involved in the development of cerebral vasospasm. The possible role of ATP in vasospasm remains unclear.

Adenosine Triphosphate↗

PubMed2001

Effect of hyperbaric oxygen on striatal metabolites: a microdialysis study in awake freely moving rats after MCA occlusion.

We have shown that hyperbaric oxygen (HBO) reduced cerebral infarction in rat middle cerebral artery occlusion model (MCAO). The present study was undertaken to evaluate the effect of HBO on ischemic striatal metabolites at different times after MCAO and reperfusion. A rat MCAO model was produced via the intraluminal filament method. After 2 h of occlusion the suture was removed and reperfusion was allowed. The rats were sacrificed at 24 h after reperfusion. HBO treatment was administered by putting rats in the HBO chamber at 3 atmospheres absolute (ATA) HBO for 1 h. Glucose, lactate, pyruvate, and glutamate in striatal extracellular fluid were collected and measured by a microdialysis system at 7, 10, and 24 h after reperfusion. Glucose, pyruvate and glutamate concentrations were increased after reperfusion. HBO treatment decreased glucose, pyruvate, and glutamate almost to the control level (preocclusion level). The lactate concentration remained unchanged after ischemic/reperfusion and after HBO treatment. This study suggested that altered brain energy metabolites and excitatory amino acids occurred during cerebral ischemia and and HBO regulated these striatal metabolites, which might contribute to the protective effect of HBO in cerebral ischemia.

Animals↗

PubMed2001

Purification and identification of an impurity in bulk hydrochlorothiazide.

Hydrochlorothiazide (6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide) (HCTZ) 1 is a widely used diuretic and anti-hypertensive. Recently, the Pharmeuropa recognized a new impurity initially thought to be an HCTZ dimer 6, which consists of the active drug (HCTZ) linked via the former beta-ring methylene to a known degradate, 5-chloro-2,4-disulfamylaniline 2. In an effort to meet a new requirement, an analytical high-pressure liquid chromatography method was developed that was selective and sensitive to the subject impurity. The impurity was concentrated and purified using a combination of solid phase extraction and reverse-phase high-pressure liquid chromatography. Subsequently, the impurity has been identified as a specific HCTZ-CH2-HCTZ isomer utilizing a variety of analytical techniques, including hydrolysis, ultraviolet spectroscopy, liquid chromatography/mass spectrometry, and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The data resulting from the application of these analytical techniques confirm the identity of the impurity as a methylene bridged pair of HCTZ molecules; however, a total of six possible isomers 7a-f exist because of the presence of three reactive amines/sulfonamides on each HCTZ molecule. One unique molecular structure (4-[[6-chloro-3,4,-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide-1,1-dioxide]-methyl]-chloro-3-hydro-H-1,2,4-benzothiadiazine-7-sulfonamide-1,1-dioxide) 7f was identified using two-dimensional COSY, NOESY, and TOCSY 1H NMR experiments.

Antihypertensive Agents↗

PubMed2001

Dual effect of HBO on cerebral infarction in MCAO rats.

Various reports in the literature have shown that hyperbaric oxygen (HBO) reduces cerebral infarction both in animals and humans. After the initial ischemic insult, however, initiating HBO treatment at different intervals has yielded conflicting results. The present study was undertaken to determine the optimal therapeutic window in which to start HBO treatment for cerebral infarction after transient focal ischemia. In this study, the operator occluded the middle cerebral artery (MCA) of anesthetized rats by introducing a blunted nylon filament into the proximal MCA from the dissected external carotid artery. When the operator removed the filament after 2 h, focal ischemia and reperfusion occurred. The operator then placed the rat in the HBO chamber and administered 3 atm absolute HBO for 1 h according to the protocol. The rat was killed 24 h after reperfusion, and the percentage of infarction (infarct ratio) was calculated by dividing the infarction area by the total area of the ipsilateral hemisphere. The results showed that the percentage of infarcted area decreased significantly (P < 0.05) both in the 3- (7.59%) and 6-h (5.35%) HBO-treatment groups compared with the control (no treatment) group (11.34%). However, the percentage of infarcted area increased significantly (P < 0.01 and P < 0.05, respectively) both in the 12- (23%) and 23-h (20%) treatment groups. The results of this study suggest that applying HBO within 6 h of ischemia-reperfusion injury could benefit the patient but that applying HBO 12 h or more after injury could harm the patient.

Animals↗

PubMed2001

Metabolic alterations in cerebrospinal fluid from double hemorrhage model of dogs.

Even though cerebral vasospasm after subarachnoid hemorrhage (SAH) causes cerebral ischemia or infarction, the metabolic alterations in cerebrospinal fluids (CSF) after SAH have not been studied. This study was undertaken to measure the levels of glucose, lactate, pyruvate and glutamate in CSF from double hemorrhage dog models. Thirty-two mongrel dogs of either sex, weighing 18-24 kg, underwent double hemorrhage by percutaneous needle puncture of the cistema magna and injection of autologous blood on day 0 and day 2. The dogs were then sacrificed on day 3, 5 and 7, after collecting CSF. In another study, the dogs were treated with mitogen-activated protein kinase (MAPK) inhibitors PD98059 and U0126, and caspase-2 and caspase-3 inhibitors from day 3 to day 6 after initial blood injection. CSF was collected on day 7 before dogs were sacrificed. The concentration of glucose, lactate, pyruvate and glutamate in CSF was measured by photometrical method. Compared with CSF collected on day 0, glucose was decreased on days 5-7, lactate was increased on days 2-7, pyruvate was increased on days 2-7, and glutamate was increased on days 3-7 (p < 0.05). In the groups treated with MAPK or caspase inhibitors, most of the metabolic alterations remained unchanged as compared with CSF from untreated dogs. Clinically, caspase inhibitors-2 and -3, and MAPK inhibitor U0126 all failed to prevent vasospasm. MAPK inhibitor PD98059 partially prevented vasospasm. Our data demonstrated a metabolic alteration of glucose, glutamate, lactate and pyruvate in CSF during cerebral vasospasm. This metabolic change in consistent with the time course of cerebral vasospasm. This study suggests that brain energy metabolites and excitative amino acids are altered during cerebral vasospasm.

Animals↗

PubMed2001

[Observation on the effect of disinfection to HBsAg by electrolyzed oxidizing water].

OBJECTIVE: Observation on the effect of disinfection on gastroscope, contaminated by hepatitis B surface antigen (HBsAg) in the electrolyzed oxidizing water (EOW). METHODS: Contaminated gastric juice and serum was added to EOW for 1 minute. Positive control samples were treated with PBS instead of EOW in the same way. Gastroscopes used for hepatitis patients were immersed in the EOW for 1 minute after cleaning. Samples were collected before and after treatment. ELISA was used to test HBsAg. RESULTS: With mixed samples (average S/N = 42.16) of EOW, HBsAg became negative when diluted in 100 times. However, the HBsAg of positive control samples remained positive. After cleaning the gastroscope (average S/N = 5.99) immersed in EOW, HBsAg became negative. CONCLUSION: EOW was effective in destroying HBsAg which could be used for gastroscope disinfection.

Disinfection↗

PubMed2001

[High level expression of human recombinant albumin gene in the yeast Pichia pastoris].

The yeast Pichia pastoris was transformed by the multi-copy Pichia expression vector that can express secreted human albumin. The high level expression of cell line was selected after screening. The expression of human recombinant albumin in Pichia pastoris induced by different methods were compared. The ratio of secreted human albumin is 80% in total secreted proteins and the expression level reaches as high as is 10 g/L.

Albumins↗

PubMed2000

Liquid chromatography-mass spectrometry and proton nuclear magnetic resonance characterization of trace level condensation products formed between lactose and the amine-containing diuretic hydrochlorothiazide.

Trace levels of condensation products between lactose and the amine-containing diuretic hydrochlorothiazide are formed when a mixture of the two solids containing 30% weight water is heated at 60 degrees C for 2 weeks. The two most abundant condensation products were characterized by liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance ((1)H NMR) spectroscopy. Under these relatively mild conditions of formation, the amine-lactose reaction products are limited to those involving the elimination of only a single molecule of water, rather than the multiple-water eliminations associated with later stages of the Maillard reaction. The spectroscopic data clearly show that the primary condensation products are cyclic N-substituted glycosylamines rather than Schiff base, 1,2-enolic forms, or Amadori rearrangement products of identical mass. In solution, the two most abundant N-substituted glycosylamines are shown to be in a kinetically slow equilibrium with each other, most likely through a mutarotation involving the intermediate formation of the acyclic Schiff base.

Chemical Phenomena↗

PubMed2000

Synovial hyperplasia in HTLV-I associated arthropathy is induced by tumor necrosis factor-alpha produced by HTLV-I infected CD68+ cells.

OBJECTIVE: To investigate the pathogenic role of macrophage lineage (CD68+) cells in synovial proliferation in patients with human T cell leukemia virus I (HTLV-I) associated arthropathy (HAAP). METHODS: Synovial tissues obtained from 3 patients with HAAP and 3 patients with osteoarthritis (OA) were examined for the expression of tumor necrosis factor-alpha (TNF-alpha) mRNA, HTLV-I tax/rex mRNA, and number of CD68 by in situ reverse transcription assay and immunohistochemistry. Western blot and flow cytometric analyses were used to determine TNF-alpha production in HTLV-I infected synoviocytes. Changes in CD68+ cell population were examined by flow cytometric analysis. Proliferative effects of supernatants of HTLV-I infected synoviocytes on normal synoviocytes were also determined. RESULTS: TNF-alpha and HTLV-I tax/rex mRNA were preferentially expressed in CD68+ cells in HAAP synovia. Infection of OA synoviocytes by HTLV-I resulted in preferential expression in CD68+ cells, and these cells produced TNF-alpha. Supernatants of HTLV-I infected synoviocytes significantly enhanced the proliferation of normal synoviocytes through a TNF-alpha dependent pathway. CONCLUSION: Our results suggest HTLV-I viral tropism for CD68+ cells, and that HTLV-I infected synoviocytes were induced to produce TNF-alpha, which enhances synovial proliferation in HAAP.

Aged↗

PubMed2000

Gene mutation in patients with primary open-angle glaucoma in a pedigree in China.

OBJECTIVE: To investigate the genetic basis of the pathogenesis of a Guangzhou (GZ.1) pedigree with primary open-angle glaucoma (POAG). METHODS: DNA fragments of the trabecular meshwork inducible glucocorticoid response protein (TIGR) gene from 4 typical POAG patients and 2 normal subjects were amplified by polymerase chain reaction (PCR). The amplified PCR fragment was cloned into a pT-Adv vector, and direct sequencing was carried out on an ABI-373 automated DNA sequencer using dyeterminator chemistry to detect the mutation. RESULTS: The TIGR gene mutation was identified in the selected subjects of this pedigree. This mutation is a "C-to-T" transition at position 370, different from that of western countries and equivalent to the position change found in Japanese patients with familial POAG. No mutation was found in the TIGR gene fragment in 2 normal subjects of the pedigree. CONCLUSIONS: These preliminary results provide insights into the pathogenesis of POAG by the TIGR gene mutation, and into the underlying action of the different mutations in oriental and western peoples.

Cytoskeletal Proteins↗

PubMed2000

[The effects of relieving space to stress distribution of mandibular implant-supported overdenture].

OBJECTIVE: To study the effects of relieving space to stress distribution of mandibular implant-supported overdenture under shocking loads. METHODS: 3-DFE method was used to make a comparative study of the effects of relieving space to stress distribution of the implant-supported overdenture under shocking loads. RESULTS: The application of stress relieving space can lower the stress peaks of the implants, periimplant tissue and the denture base. The highest stress of compression in lateral bone-implants interface reduced 52%. CONCLUSION: The application of stress relieving space can be helpful to protect implants, periimplant tissue and denture base.

Dental Prosthesis, Implant-Supported↗