Biomedical subjects

Y Tian

Publications and source records attributed to Y Tian.

At least 55 records · Page 3Linked to original sources

PubMed2001

Clinical outcome of patients with previous myocardial infarction and left ventricular dysfunction assessed with myocardial (99m)Tc-MIBI SPECT and (18)F-FDG PET.

UNLABELLED: Myocardial viability was assessed by (99m)Tc-methoxyisobutylisonitrile (MIBI) SPECT and (18)F-FDG PET to evaluate the prognosis and treatment strategy of patients with myocardial infarction (MI) and left ventricular (LV) dysfunction. METHODS: One hundred twenty-three consecutive patients with previous MI and LV dysfunction (LV ejection fraction [EF], 35% +/- 6% [mean +/- SD]) who underwent (99m)Tc-MIBI SPECT and FDG PET were followed-up for 26 +/- 10 mo (mean +/- SD). Distributions of the 2 radiotracers in myocardial segments were classified into 2 patterns: myocardial perfusion-metabolism mismatch (MM) and match (M). LV EF and LV end-diastolic diameter (EDD) were measured by echocardiography at baseline, 3 mo (Pos1), and 6 mo (Pos2) after revascularization. Cardiac death, acute MI, unstable angina, and late revascularization (>3 mo) experienced by the patients during follow-up were defined as cardiac events. RESULTS: Sixty-seven patients underwent revascularization and 56 patients were treated medically. Of the 72 patients with > or =2 MM segments, 42 underwent revascularization (group A1) and 30 were treated medically (group A2). Of the 51 patients with <2 MM segments, 25 underwent revascularization (group B1) and 26 were treated medically (group B2). The 4 groups had similar baseline characteristics and rest LV EF. After revascularization, EF (mean +/- SD) increased in group A1 from 36% +/- 5% to 44% +/- 8% (P < 0.0001) in Pos1 and to 51% +/- 9% (P < 0.0001) in Pos2. EDD (mean +/- SD) decreased from 62 +/- 8 mm to 56 +/- 5 mm (P < 0.001) in Pos1 and to 55 +/- 5 mm (P < 0.001) in Pos2. However, EF and EDD were unchanged in group B1 (P > 0.05). During the follow-up, 22 patients (17.9%) suffered from cardiac events, including 11 cardiac deaths, 4 acute MI, 6 late coronary artery bypass grafting, and 1 unstable angina pectoris. The cardiac event rate in group A2 (50%) was significantly higher than that of groups A1 (2.4%; chi(2) = 23.08; P < 0.0001), B1 (12%; chi(2) = 8.94; P = 0.003), and B2 (11.5%; chi(2) = 9.45; P = 0.002). CONCLUSION: Assessment of myocardial viability using hybrid (99m)Tc-MIBI SPECT and FDG PET can predict the clinical outcome and is helpful to decision making in the treatment strategy of patients with MI and LV dysfunction. Revascularization can improve the LV function and clinical outcome of patients with >2 viable myocardial segments.

Aged↗

PubMed2001

[A simulating study of biophysical features along meridians on a gel model].

A physical model was used to study the mechanism of specific biophysical features along the classic acupuncture meridian lines. A sol channel within a gel bed was made by a resistance string heating during electrification. A saline channel was produced by withdrawing some fibers in the gel bed and injecting saline into the gaps. A hydraulic resistance instrument composed by two pressure transducers was used to measure the hydraulic resistance across the two kinds of channels. The impedance on both channels was measured by a four-electrode impedance instrument with 5 KHz constant current. A vibration generator was put on one set of the channel to produce about 50 Hz sound waves. The signal was detected by a crystal pickup on the other set of the channel to examine the transmission of the wave along the two kinds of channels. The results showed that the low hydraulic resistance appeared on saline channel while no such feature on sol channel. Both channels showed low impedance while saline channel had more marked low impedance than control area. There was a better transmission of sound wave along saline channel while a bad transmission along the sol channel. The results suggest that the specific biophysical feature along meridians may be caused by a continuous rich distribution of interstitial fluid which mainly contains salt, water and protein.

Electric Impedance↗

PubMed2001

[A study of mutation(s) of the epithelial sodium channel gene in a Liddle's syndrome family].

OBJECTIVE: To study the genetic mechanism of Liddle's syndrome in a family and help the diagnosis (specially ante-natal) and treatment of Liddle's syndrome clinically. METHODS: (1) Physical examination and measurement of serum potassium, plasma aldosterone and renin activity respectively by biochemical and radioimmunological assays were made for the member of the family. (2) Venous blood samples were collected from the members of the family and total genomic DNA was prepared. One set of specific primers was used for direct polymerase chain reaction, for amplifying C terminus of beta-subunit of epithelial sodium channel (hbetaENaC). Polymerase chain reaction products were subjected to single-strand conformation polymorphism and direct DNA sequence analysis. RESULTS: A new frameshift mutation (1bp, INS, 600G) of the gene of C terminus of beta-subunit of hbetaENaC was found in the Liddle's syndrome family. This mutation introduced a new stop codon at position 605 and deleted the last 34 normal amino acids from the C teminus of hbeta ENaC. Eight genetically affected subjects had severe hypertension and suppressed levels of plasma aldosterone and plasma renin activity; half of them had hypokalemia. CONCLUSION: The frameshift mutation (1bp, INS, 600G) of hbetaENaC gene is the likely cause of Liddle's syndrome in this Chinese family.

Adolescent↗

PubMed2001

[A clinicopathologic study on 9 cases of epithelioid hemangioendothelioma].

OBJECTIVE: To study the clinicopathological features of epithelioid (histiocytoid) hemangioendothelioma (EHE). METHODS: 9 cases of EHE were examined by light microscopy and immunohistochemistry, 1 case with ultrastructural observation. RESULTS: The patients' age ranged from 16 to 47 years (mean 32 years). The lesions occurred in both sexes and presented at a variety of sites including head and facial area (4 cases), upper limbs (3 cases) and lower limbs (2 cases). The morphological characters were: (1) "epithelioid" or "histiocytoid" tumor cells; (2) rounded or polygonal tumor cells arranged in nests, cords and irregular patterns; (3) the tumor cells were embedded in myxoid or hyaline matrix; (4) primitive lumen formation within a single tumor cell (intracytoplasmic lumens); (5) lack of pleomorphism, mitotic activity and necrosis; (6) presence of spindle cell hemangioendothelioma in some cases; (7) osteoclast like giant cells scattered throughout the entire lesion were observed in one case. Immunohistochemistry studies on 7 cases found that tumor cells were positive for vimentin (7/7), factor VIII-RAg (5/7), CD31 (5/7), CD34 (5/7), cytokeratin (2/7), CD68 and alpha-AT (1/7). Ultrastructural study of 1 case demonstrated Weibel-Palade bodies and an abundance of intermediate filaments in the cytoplasm. The follow-up of 6 cases found that 3 cases developed local recurrences but none of them metastasized. CONCLUSIONS: EHE is a distinctive low-grade sarcoma whose etiology remains unknown. Recognizing its morphological characters is important to avoid confusion with other similar lesions.

Adolescent↗

PubMed2001

[Prospective double-blind randomized trial of cryoanalgesia: experimental and clinical study].

OBJECTIVE: To alleviate and prevent postthoracotomy severe chest pain. METHODS: In dogs, intercostal nerves were freezed at -50 degrees C at different times. Pathological changes and repair process of the nerves were observed while identifying the best freezing time that could be used clinically. Prospective double-blind randomized trial in 200 patients who had undergone thoracotomy was carried out from January 1996 to June, 2000. Cryoanalgesia(Cryo group) and control group consisted of 100 patients. Before closing chest, 4 routes of costal nerves (incision, above and below incision, and one for inserting drainage tube) were freezed for 1.5 minutes separately. Postoperative incision pain was recorded by VAS(visual analogue scales) including recording the dosage of narcotics, pulmonary function on 3, 7, 15, 30, 90 postoperative days. RESULTS: Pathological changes of the axons and myelin sheaths progressed along with freezing time from 30 seconds to 2 minutes, but recovered in about one month. As the best freezing time, 1.5-minute freezing provided effective analgesia and quick recovery. Clinical application showed strong analgesia effect. VAS score of the cryo-group and control group was 2.29, and 7.24 (P < 0.001) respectively. In the cryo-group, no pain (0 degree) was observed in 22 patients (22%), very slight pain (1-2 degrees) in 44(44%), slight pain (3-4 degrees) in 20 (20%), and moderate pain (5-6 degrees) in 8 (8%). The total effective rate (0-6 degrees) was 94%. Dosage of dolantin in the cryo- and control groups was 41.3 mg and 185 mg, respectively(P < 0.001). The changes of pulmonary function for the two groups were not significant. CONCLUSION: Freezing intercostal nerves during thoracotomy can effectively prevent postoperative chest pain. The pathological changes of nerves are reversible.

Adolescent↗

PubMed2001

Three-dimensional correction of scoliosis using TSRH instrumentation.

OBJECTIVE: To evaluate the results of TSRH instrumentation in the correction of coronal, sagittal and rotational deformity of scoliosis. METHODS: From January 1998 to December 1999, thirty-two consecutive patients (6 males, 26 females)with scoliosis underwent anterior or posterior spinal instrumentation and fusion using TSRH instrumentation. Of these cases, 21 were idiopathic scoliosis and 11 were congenital scoliosis. The average age at surgery was 16.4 years (range, 11 approximately 45 years). The mean Cobb angle at surgery was 71.2 degrees range, 44 degrees approximately 125 degrees) in the coronal plane, and 49. degrees range, 16 degrees aprroximately 67degrees in the sagittal plane. Rotational deformity (Nash-Moe) ranged from I to III degree. Preoperative apical translation averaged 4.8 cm (range, 3 approximately 9 cm). RESULTS: The average follow-up duration was 13.3 months (range, 10 approximately 24 months). At the final follow-up, the mean Cobb angle in the coronal plane was 26.6 (range, 10 degrees approximately 73 degrees), with a 63.8% of improvement. Sagittal alignment was well maintained with a mean Cobb angle of 28 degrees (range, 10 degrees approximatelky 45 degrees). The average correction of rotation of the apical vertebra was I degree. The average apical translation was 1.6 cm (range, 0.5 approximately 5.0 cm) representing a correction rate of 66, 7%. Complication was noted in two cases with an incidence of 3.1%, one case had superficial infection and the other one had lower hook dislocation. There was no neurologic deficit and pseudoarthrodesis in this series. CONCLUSION: TSRH instrumentation is an effective and convenient three-dimensional correction system with a lower rate of complication, which can not only correct the coronal and rotational deformity, but maintain the sagittal alignment as well.

Adolescent↗

PubMed2000

Analysis of cytogenetic and developmental effects on pre-implantation, mid-gestation and near-term mouse embryos after treatment with trichlorfon during zygote stage.

Trichlorfon has been widely used in agriculture as a broad spectrum insecticide. We examined cytogenetic and developmental effects on early mouse zygotes exposed to trichlorfon in vivo. Pregnant female mice were intraperitoneally administered a single dose of trichlorfon (100 or 200mg/kg) at 6h post presumed conception and either sacrificed on day of gestation (dg) 3, 9 or 17 to assess the developmental toxicity and mutagenic effects on embryos. Mean cell number (dg 3) and somite number (dg 9) of embryos in the two trichlorfon-treated groups were significantly fewer than in the control group and the mean micronucleus (MN) number (dg 3) and the frequency of mosaic aneuploidies including monosomic or trisomic cell lines (dg 9) was significantly increased in both trichlorfon-treated groups compared with the control group. However, there was no difference in fetal body weight (dg 17) between the control and trichlorfon-treated groups and no increased incidence of external malformations was observed in the trichlorfon-treated groups. These findings suggest that acute exposure of trichlorfon around fertilization induces a high frequency of MN, mosaic aneuploidies and developmental retardation in pre-implantation and mid-gestation embryos, and thereafter these embryos with MN or chromosome damage appear to develop past mid-gestation and catch up with normal embryos by near-term.

Abnormalities, Drug-Induced↗

PubMed2000

Supercritical fluid extraction of catechins from Cratoxylum prunifolium dyer and subsequent purification by high-speed counter-current chromatography.

Supercritical fluid extraction of tea catechins including epigallocatechin-3-O-gallate (EGCG) and epicatechin-3-O-gallate (ECG) from Cratoxylum prunifolium Dyer was performed. The optimization of parameters was carried out using an analytical-scale supercritical fluid extraction (SFE) system designed in our laboratory. Then the extraction was scaled up by 100 times using a preparative SFE system under a set of optimized conditions of 40 degrees C, 25 MPa and modified CO2 with 80% ethanol aqueous solution. The combined yield of EGCG and ECG reached about 1 mg per 1 g of tea leaves where the solubility was near 1.4 x 10(-4) mass fraction of CO2 fluid. EGCG and ECG of high purity (>98%) were obtained from the crude preparative extract by high-speed counter-current chromatography.

Catechin↗

PubMed2000

Identification of a renal-specific oxido-reductase in newborn diabetic mice.

Aldose reductase (ALR2), a NADPH-dependent aldo-keto reductase (AKR), is widely distributed in mammalian tissues and has been implicated in complications of diabetes, including diabetic nephropathy. To identify a renal-specific reductase belonging to the AKR family, representational difference analyses of cDNA from diabetic mouse kidney were performed. A full-length cDNA with an ORF of 855 nt and yielding a approximately 1.5-kb mRNA transcript was isolated from a mouse kidney library. Human and rat homologues also were isolated, and they had approximately 91% and approximately 97% amino acid identity with mouse protein. In vitro translation of the cDNA yielded a protein product of approximately 33 kDa. Northern and Western blot analyses, using the cDNA and antirecombinant protein antibody, revealed its expression exclusively confined to the kidney. Like ALR2, the expression was up-regulated in diabetic kidneys. Its mRNA and protein expression was restricted to renal proximal tubules. The gene neither codistributed with Tamm-Horsfall protein nor aquaporin-2. The deduced protein sequence revealed an AKR-3 motif located near the N terminus, unlike the other AKR family members where it is confined to the C terminus. Fluorescence quenching and reactive blue agarose chromatography studies revealed that it binds to NADPH with high affinity (K(dNADPH) = 66.9 +/- 2.3 nM). This binding domain is a tetrapeptide (Met-Ala-Lys-Ser) located within the AKR-3 motif that is similar to the other AKR members. The identified protein is designated as RSOR because it is renal-specific with properties of an oxido-reductase, and like ALR2 it may be relevant in the renal complications of diabetes mellitus.

Aldehyde Reductase↗

PubMed2000

Investigation of the in vitro release of gentamicin from a polyanhydride matrix.

Septacin¿trade mark omitted¿ is a sustained release formulation consisting of gentamicin sulfate dispersed in a biodegradable polyanhydride matrix. The polyanhydride matrix is a copolymer of erucic acid dimer (EAD) and sebacic acid in a 1:1 weight ratio. In vitro drug release was performed in both water and pH 7.4 phosphate buffer. The drug release in water was faster than that in the buffer, which was the opposite of what would be expected based upon a faster polymer hydrolysis rate in the buffer. Theoretical treatment of the data using the Peppas model revealed that release in water was anomalous, while the release in pH 7.4 phosphate buffer was diffusion-controlled. Profound bead morphology differences were observed between beads in these two in vitro release media. Cracking was observed in beads in water and swelling with no apparent cracking was seen in beads in buffer. Concurrent monitoring of drug and sebacic acid release indicated that drug release is not via surface erosion. Osmotic effects were found to play little role in the in vitro drug release. There was no spectroscopic evidence of amide formation between the drug and copolymer. Sulfate release was monitored along with drug release and the results indicate that there is ion-exchange occurring during the pH 7.4 in vitro release. It was subsequently demonstrated that gentamicin can form an insoluble salt with EAD. This salt formation explains the slower drug release in pH 7.4 phosphate buffer.

Decanoic Acids↗

PubMed2000

Determination of apparent thermodynamic parameters for adsorption of a midchain peptidyl residue onto a glass surface.

Protein adsorption onto the surface of an implanted material is widely recognized as an important factor controlling the biological response. Although numerous studies have been conducted to investigate protein adsorption behavior, very little is actually understood regarding the specific molecular events involved in protein-surface adsorption processes. As a basic science approach to investigate protein-surface interactions, an experimental method is developed and applied to determine apparent thermodynamic parameters for the adsorption of a single midchain peptidyl residue onto a glass surface. This article presents the results of adsorption studies for four molecular weight ranges of poly-L-lysine onto glass microspheres in physiologic saline at four temperatures. Isotherm data plots are constructed and the apparent changes in enthalpy (DeltaH degrees ), entropy (DeltaS degrees ), and Gibbs' free energy (DeltaG degrees ) are calculated assuming a Langmuir-like model for adsorption. Estimates of apparent DeltaH degrees, DeltaS degrees, and DeltaG degrees for the adsorption of a single midchain lysine residue are determined from the initial slopes of the plots of the apparent thermodynamic parameters versus the degree of polymerization of the adsorbed poly-L-lysine. It is proposed that the generation of such molecular-level adsorption data is a necessary step toward the goal of understanding, predicting, and controlling protein-surface interactions.

Adsorption↗

PubMed2000

Blood-brain barrier disruption and complement activation in the brain following rapid correction of chronic hyponatremia.

In previous studies we developed a rat model in which demyelination is reproducibly produced following rapid correction of chronic hyponatremia and demonstrated that the development of demyelination in this model is strongly associated with NMR indices of blood-brain barrier (BBB) disruption. Because complement is toxic to oligodendrocytes, we evaluated the hypothesis that BBB disruption precipitated by correction of hypoosmolality is followed by an influx of complement into the brain, which then contributes to the demyelination that occurs under these conditions. We studied four groups of rats with immunocytochemical analysis using primary antibodies to IgG and the C3d split-fragment of activated complement: (1) normal rats; (2) rats in which hyponatremia was maintained for 7 days; (3) chronically hyponatremic rats in which the plasma [Na(+)] was rapidly corrected with hypertonic saline administration 20 h prior to perfusion; and (4) chronically hyponatremic rats in which the plasma [Na(+)] was rapidly corrected with hypertonic saline administration 5 days prior to perfusion. In normonatremic and uncorrected hyponatremic rats only background staining was observed in areas lacking a BBB and in blood vessel walls, whereas marked increases in IgG and C3d staining were seen in the brains of rats both 20 h and 5 days after rapid correction of hyponatremia. The staining intensity was significantly correlated with the degree of neurological impairment. These results provide evidence for functional BBB disruption following rapid correction of hyponatremia and support the hypothesis that complement activation may be involved in the pathogenesis of osmotic demyelination.

Animals↗

PubMed2000

The relationship between apoptosis and the expression of proliferating cell nuclear antigen and the clinical stages in gastric carcinoma.

The relationship between the apoptosis and the expression of proliferating cell nuclear antigen (PCNA) and the clinical stages in gastric cancers was studied. By using terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) technique and PCNA immunohistochemical staining, the apoptosis and the expression of PCNA in tissue of gastric carcinoma were assayed in situ, the index of apoptosis (AI), index of PCNA (PI) and the rate of AI/PI were calculated. AI and PI in gastric cancer tissues were (6.5 +/- 3.7)% and (49.8 +/- 15.9)% respectively, and the rate of AI/PI was 0.13 +/- 0.05, which were obviously different from those of normal gastric mucosa in paragastric cancer (P < 0.01). With the advanced TNM stages of gastric carcinoma, the AI was decreased, PI was increased and the rate of AI/PI decreased in gastric carcinoma. There was significant difference in them between the gastric cancer tissues and normal gastric mucosa in pericarcinoma in TNM stage II to IV (P < 0.05). It was suggested that the decreased apoptotic cells and the increased proliferating cells were obviously related to the tumor genesis and tumor progression in gastric carcinoma. The AI, PI and the rate of AI/PI would become the prognostic factors in advanced gastric carcinoma.

Adenocarcinoma↗

PubMed2000

Effect of vagotomy on acute pancreatitis in rats.

One hundred and eighty-two SD rats were randomly divided into the normal control group, fast operating group and food-intake operating group. The experimental model of acute pancreatitis (AP) in rats was established by injecting 5% sodium taurocholate into the pancreatic duct of rat according to Aho's method. The sandostatin was used for positive contrast. The concentrations of serum amylase, calcium, C reaction protein (CRP) and interleukin-6 (IL-6) were assayed respectively at different time points. The pathological sections were observed. Each operating group contained 10 rats. The mortality of the operating groups was observed during the 24 h. The serum amylase level in the AP rats was reduced after receiving vagotomy (VG, P < 0.05). Although the serum calcium level in most groups was decreased, the reduction in the group with VG plus sandostatin was not obvious (P > 0.05). The increase of CRP and IL-6 was not obvious after VG (P > 0.05). The change of mortality was not significant (P > 0.05). The pathological sections showed that the AP pathological change was mild after VG. The disease condition of food-intake operating group was more serious than that of fast operating group. It was suggested that VG had some influence on the prognosis of AP in rats.

Acute Disease↗

PubMed2000

Toxicity of magnetic albumin microspheres bearing adriamycin.

Magnetic albumin microspheres bearing adriamycin (ADM-MAM) is a novel chemotherapeutic compound with site-specific drug delivery characteristics. The acute and subacute toxic tests of the compound, local irritating test and anaphylactic test were performed on mice and guinea pigs. The results showed there was no macroscopically and microscopically direct cytotoxic injuries of the compound to the animal organs or to the cells. The LD50 value of the compound was higher than that of the single used adriamycin, indicating that the compound was less toxic than the single adriamycin and quite safe in its therapeutic dosage. Furthermore, there was also no side effects or toxic reactions to be observed on clinical patients with advanced carcinoma or gastric cancer.

Albumins↗

PubMed2000

Effect of cardiopulmonary bypass on beta adrenergic receptor-adenylate cyclase system on surfaces of peripheral lymphocytes.

The experimental results showed that the level of CAMP, the ratio of cAPM to cGMP, IL-2R expression and IL-2 production in vitro in lymphocytes immediate and 2 weeks after cardiopulmonary bypass (CPB) were significantly lower than those before anesthetics in the patients undergoing cardiac surgery with CPB. These findings suggested that CPB could cause serious damage to adrenergic beta receptor-adenylate cyclase system on circulating lymphocytes surfaces, which might be one of the mechanisms resulting in immunosuppression after open heart surgery with CPB.

Adenylyl Cyclases↗

PubMed2000

A commercial preparation of catalase inhibits nitric oxide production by activated murine macrophages: role of arginase.

Catalase is widely used as a pharmacological probe to evaluate the role of hydrogen peroxide in antimicrobial activities of phagocytic cells. This report demonstrates that the ability of a commercial preparation of catalase to inhibit concomitantly macrophage antimycobacterial activity and production of reactive nitrogen intermediates can be attributed, at least in part, to the depletion of L-arginine by contaminating arginase. In experimental systems that employ pharmacological probes, the existence of nonspecific effects should be considered in data interpretation.

Animals↗

PubMed2000

Expression characteristics and relevance of sodium glucose cotransporter-1 in mammalian renal tubulogenesis.

Expression and role of sodium glucose cotransporter (SGLT-1) in tubulogenesis were investigated during renal development. A mouse SGLT-1 cDNA was cloned, and it had substantial homology with human and rat forms. Four mRNA transcripts were detected, which differed in size from other species. SGLT-1 transcripts were detected at day 13 of gestation, and their expression increased during later stages extending into the postnatal period. A high mRNA and protein expression of SGLT-1 was seen in tubular segments of the inner cortex and outer medulla at day 16, and it was developmentally regulated. Treatment with SGLT-1 antisense selectively decreased the population of tubules in the metanephric explants. Expression of glomerular mRNA and WGA binding were unchanged. SGLT-1 activity, as measured by [(14)C]methyl-alpha-D-glucopyranoside uptake, increased during gestation in the tubular segments where it is expressed. Glucose uptake was inhibited by the treatment with SGLT-1 antisense and D-galactose. The data suggest that SGLT-1 exhibits a restricted spatiotemporal expression with functional activity confined to the corresponding tubular segments, and it selectively maintains renal tubulogenesis during development.

Amino Acid Sequence↗