Biomedical subjects

Z Yu

Publications and source records attributed to Z Yu.

At least 37 records · Page 2Linked to original sources

PubMed2004

Impact of combined mycophenolate mofetil and low-dose calcineurin inhibitor therapy on renal function, cardiovascular risk factors, and graft function in liver transplant patients: preliminary results of an open prospective study.

As liver transplantation (LT) is now being performed with excellent 1-year graft survival rates of 85% to 90%, attention has been shifted to reducing long-term complications of calcineurin inhibitors (CNI). We randomized LT patients (2:1) who displayed renal dysfunction under CNI treatment to either mycophenolate mofetil (MMF) (1000 mg twice a day) followed by stepwise reduction of CNI (n = 21; Tac trough levels <4 ng/mL, CsA trough levels <50 ng/mL); or continue their current CNI dose (n = 11; control group). Three months after study entry, we observed significantly decreased mean values in the CNI reduction group of serum creatinine (1.88 +/- 0.36 versus 1.58 +/- 0.33 mg/dL, P < .001) and BUN (39.2 +/- 11.8 versus 29.9 +/- 9.59 mg/dL, P < .001) with a significantly increased GFR (51.4 +/- 10.8 versus 61.6 +/- 14.1 mL/min, P < .001). Improved renal function in these long-term LT recipients (5.6 +/- 3.6 years posttransplant; range, 2 to 13 years) suggests at least a partial reversibility of CNI-induced renal damage. Furthermore, we found an improved lipid profile as well as a significantly decreased mean systolic (140 +/- 19 versus 130 +/- 14 mm Hg, P < .01) and diastolic (82 +/- 9 to 74 +/- 8 mm Hg, P < .001) blood pressure 3 months after introduction of MMF therapy. Additionally, transaminases significantly improved in the CNI reduction group within this time period (ALT 37.9 +/- 25.9 versus 25.2 +/- 13.2, P < .05). MMF and CNI-reduced immunosuppressive regimens may improve long-term patient survival, suggesting a broad application within the liver transplant setting.

Aged↗

PubMed2004

[Edema and the nephrotic syndrome].

If proteinuria is of sufficient amount, and persists for long enough, then a series of consequences arises which is called the nephrotic syndrome. The most notable consequence of massive proteinuria is salt and water retention leading to edema formation. This edema is found in association with proteinuria usually greater than 3.5 g/day, accompanied by hypoalbuminemia, usually less than 25 g/l. The underlying disease is usually a glomerulonephritis, albeit in rare situations severe renal artery stenosis can lead to proteinuria by hyperfiltration. Two theories have been proposed. In the classical "underfill" theory edema is considered to be secondary to salt retention resulting from renal hypoperfusion. According to this theory the primary event is the decrease in plasma volume due to the diminution of plasma oncotic pressure resulting from hypoalbuminemia, causing transfer of fluid from the plasma to the interstitial space "underfilling" the blood compartment and resulting to secondary renal sodium retention. This mechanism applies mainly to the nephrotic syndrome associated with minimal change disease observed in children. By contrast, in most adults with the nephrotic syndrome due to minimal change disease or other glomerular lesions such as membranous or proliferative glomerulonephritis, an initial plasma volume expansion is observed. Therefore, the primary event responsible for the sodium retention is a renal intrinsic excretory defect, which leads to extracellular fluid expansion and edema formation. Therapy is specific for the specific glomerular disease and symptomatic for the edema (diuretics), anticoagulation therapy for prevention of venous thrombosis and embolism, antibiotics for infections, and most of all, omission of triggering factors such as specific xenobiotics.

Adult↗

PubMed2004

Mutation of Gluconobacter oxydans and Bacillus megaterium in a two-step process of l-ascorbic acid manufacture by ion beam.

AIM: To increase the transformation rate of l-sorbose to 2-keto-l-gulonic (2-KLG) acid in a two-step process of l-ascrobic acid manufacture by ion beam. METHODS AND RESULTS: Gluconobacter oxydans (GO29) and Bacillus megaterium (BM80) were used in the present study. Ion implantation was carried out with the heavy ion implantation facility at the institute of Plasma Physics in China. 2-KLG in whole culture broth was determined by iodometry. Mutants were screened by single-colony isolation and 2-KLG accumulation in broth. GO29 and BM80 were implanted by either hydrogen ions (H(+)) or nitrogen ions (N(+)) with various doses, respectively. The average transformation rate of GM112-302 bred by ion beam in Gram-molecule was increased from 79.3 to 94.5% after eight passages in shaking flasks. Furthermore, in 180-ton fermentors in Jiangsu Jiangshan Pharmaceutical Co. Ltd, the transformation rate was stable at 92.0%, indicating a producer could get 0.99 kg of gulonic acid from 1.0 kg of sorbose. CONCLUSION: Ion beam as a new mutation source had potential advantages in breeding. Comparing with original mixture GO29 and BM80, GM112-302 is more efficient in accumulating 2-KLG, especially at the later phase. SIGNIFICANCE AND IMPACT OF THE STUDY: GM112-302 bred by ion beam implantation dramatically increased the transformation rate by 19.2%, which greatly increased efficiency and reduced the cost of l-ascorbic acid manufacture in a two-step process.

Ascorbic Acid↗

PubMed2004

Application of electrospray ionization mass spectrometry in rapid typing of fengycin homologues produced by Bacillus subtilis.

AIMS: To rapidly type the fengycin homologues produced by Bacillus subtilis strains with electrospray ionization/collision-induced dissociation (ESI/CID) mass spectrometry. METHODS AND RESULTS: Fengycin homologues produced by Bacillus subtilis JA were analysed. When each homologue was subjected to ESI/CID analysis, ions representing characteristic fragmentations were detected. These ions can help to identify the homologues; even homologues of the same nominal mass can be discriminated by their ESI/CID spectra. Based on the CID results, fengycin homologues can be correctly assigned. CONCLUSIONS AND SIGNIFICANCE OF THIS STUDY: ESI/CID leads to rapid detection and structural characterization of fengycin homologues or lipopeptides with similar properties. It will be very useful in studying the regulatory expression of these peptides.

Bacillus subtilis↗

PubMed2003

A phase 1 study of tazarotene in adults with advanced cancer.

Tazarotene is an acetylenic retinoid which is metabolised to tazarotenic acid and which binds selectively to the retinoid receptors RARbeta and RARgamma. The safety, toxicity and pharmacokinetics of oral tazarotene were determined over 12 weeks of treatment in 34 patients with advanced cancer. Commonly seen toxicities were mucocutaneous symptoms, musculoskeletal pain and headache. Dose-limiting toxicities were hypercalcaemia, hypertriglyceridaemia and musculoskeletal pain. The maximum tolerated dose of tazarotene in this schedule is 25.2 mg day(-1). Plasma concentrations of tazarotenic acid were found to peak rapidly within 1-3 h of dosing and thereafter declined quickly. The C(max) and AUC values on day 0, and weeks 2 and 4 were similar indicating no drug accumulation. The dose-normalised C(max) and AUC values at different dose levels and different study days appeared to be similar indicating linear pharmacokinetics. No objective responses were seen, although stable disease was seen in six out of eight evaluable patients receiving the three highest dose levels of tazarotene (16.8, 25.2 or 33.4 mg day(-1)). We conclude that oral tazarotene is well tolerated when administered daily for 12 weeks, has a favourable toxicity profile compared with other retinoids and merits further investigation as an anticancer therapy.

Adult↗

PubMed2003

Human apoC-IV: isolation, characterization, and immunochemical quantification in plasma and plasma lipoproteins.

Apolipoprotein C-IV (apoC-IV), the newest member of the low-molecular-weight apoC group, has been characterized in blood plasma of rabbits, in which it is a major proline-rich apoC component (Zhang, L-H., L. Kotite, and R. J. Havel. 1996. Identification, characterization, cloning, and expression of apoC-IV, a novel sialoglycoprotein of rabbit plasma lipoproteins. J. Biol. Chem. 271: 1776-1783). Although the decoded sequence of mouse and human apoC-IV is known, apoC-IV has not been identified in blood plasma from these or other species. Rabbit apoC-IV exists in several sialoforms, and the asialoform has an acidic isoelectric point. We show that apoC-IV is a basic protein in human, monkey, and mouse plasma, present as a minor apoC component of VLDL. Human apoC-IV, isolated from apo VLDL by DEAE-cellulose chromatography and two-dimensional electrophoresis, was identified by microsequencing four tryptic peptides. The protein exhibits two major isoforms; one is N-glycosylated, and both are variably sialylated. In normolipidemic plasma, greater than 80% of the protein is in VLDL (0.7% of total apo VLDL), with most of the remainder in HDL. The concentration of apoC-IV in the plasma and lipoproteins of rho < 1.21 g/ml is closely related to plasma triglyceride concentration up to 1,770 mg/dl, varying from 0.1-1.9 mg/dl. Neither the human nor rabbit apoC-IV gene contains a typical TATA box in the 5'-flanking region, but the 5'-untranslated region of the rabbit gene contains a unique purine-rich sequence, GGGACAG(G/A), repeated nine times in tandem, with an additional two within the 5'-flanking sequence. This sequence, functioning as a GAGA box that has been implicated in the transcription of a number of genes, may explain the higher level of expression of apoC-IV in rabbits.

5' Untranslated Regions↗

PubMed2003

Linking chemical reactivity and protein precipitation to structural characteristics of foliar tannins.

Tannins influence ecosystem function by affecting decomposition rates, nutrient cycling, and herbivory. To determine the role of tannins in ecological processes, it is important to quantify their abundance and understand how structural properties affect reactivity. In this study, purified tannins from the foliage of nine species growing in the pygmy forest of the northern California coast were examined for chemical reactivity, protein precipitation capacity (PPC), and structural characteristics (13C NMR). Reactivity of purified tannins varied among species 1.5-fold for the Folin total phenol assay, and 7-fold and 3-fold, respectively, for the acid butanol and vanillin condensed tannin assays. There was about a 5-fold difference in PPC. Variation in chemical reactivity and PPC can be largely explained by differences in structural characteristics of the tannins determined by 13C NMR. In particular, the condensed versus hydrolyzable tannin content, as well as the hydroxylation pattern of the B-ring and stereochemistry at the C-2-C-3 position appear to influence reactivity. Due to the large differences in chemical reactivity among species, it is necessary to use a well-characterized purified tannin from the species of interest to convert assay values to concentrations. Our results suggest that structural characteristics of tannins play an important role in regulating their reactivity in ecological processes.

Animals↗

PubMed2003

Technical note: Specific PCR amplification of protozoal 18S rDNA sequences from DNA extracted from ruminal samples of cows.

A protozoa-specific primer (P-SSU-342f) was designed and paired with a eukarya-specific primer to amplify a 1,360-bp fragment of DNA encoding protozoal small subunit (SSU) ribosomal RNA from ruminal fluid of cows fed a mixed forage:grain diet or alfalfa hay. Sequencing of clones showed that P-SSU-342f is specific to ruminal protozoa and, with slight modifications, the primer will be useful for ecological studies of ruminal protozoa.

Animals↗

PubMed2002

A direct continuous pH-spectrophotometric assay for arginine kinase activity.

A direct and continuous spectrophotometric method was developed for determining arginine kinase (phosphoarginine synthesis) activity. Protons are produced during the phosphoarginine synthesis course, so adding the complex acid-base indicator to this solution and monitoring the decrease of absorbance of the solution at 575 nm will follow the arginine kinase activity. For this condition, one activity unit of arginine kinase was defined as 1 micromol H+ produced in 1 minute in the enzymatic reaction catalyzed by arginine kinase.

Arginine Kinase↗

PubMed2001

[The protective effect of low molecular weight heparin on early nephropathy in diabetic rats].

OBJECTIVE: To investigate the protective effect of low molecular heparin on early nephropathy in diabetic rats and to explore its possible mechanism. METHODS: The rats were randomly divided into following groups: normal control rats, streptozotocin (STZ, 65 mg/kg)-induced diabetic rats and diabetic rats treated with low molecular weight heparin (Fraxiparine, Nadroparin calcium 205 AXaIU/kg). The activity of anti-Xa factor and the activated partial thromboplastin time (APIT) in plasma were assayed, the renal function and profile of kidney hypertrophy were measured, and the renal tissue were observed by light microscopy after 1, 2, 4 weeks of the treatment respectively. RESULTS: Compared with the untreated diabetic group, except for higher kidney hypertrophy index, LMWH treated diabetic rats presented less urinary albumin excretion, lower creatinine clearance rate (Ccr) and longer APTT than diabetic group without any treatment. Meanwhile, renal pathologic changes in LMWH treated group were improved. CONCLUSION: Low molecular weight heparin possesses a renal protective effect on early diabetic nephropathy and its possible mechanism may be associated with the beneficial effect of LMWH on regulating abnormal diabetic renal hemodynamics.

Animals↗

PubMed2001

[The change of human Na+/dicarboxylate co-transporter 1 expression in the kidney and its relationship with pathogenesis of nephrolithiasis].

OBJECTIVE: To study the change of Na+/dicarboxylate co-transporter 1 expression in the kidney and its relationship with nephrolithiasis. METHODS: 50 volunteers and 85 patients with nephrolithiasis were divided into 3 groups: control, nephrolithiasis with normal urine citrate, and nephrolithiasis with hypocitraturia. The expression of hNaDC1 mRNA in kidney was determined by RT-PCR or Northern blotting, the change of hNaDC1 protein abundance were measured by immunohistochemical staining with anti-hNaDC1 antibody among part of these patients and volunteers. The plasma and urinary biochemical parameters, such as citrate, oxalate, uric acid and calcium etc., were analyzed by routine chemical methods. RESULTS: The recurrence rate of nephrolithiasis in the group of patients with hypocitraturia was 36.1%, significantly higher than the recurrence rate of 16.3% in the group of patients with normal urine citrate (P < 0.01). hNaDC1 was expressed in the normal kidney, localized in the striated border of renal proximal tubule. However, it was expressed highly in the kidneys of patients with hypocitraturia. The ratio hNaDC1 mRNA/18sRNA in the patients with hypocitraturia was 0.65 +/- 0.21, significantly higher than that in the controls (0.36 +/- 0.11, P < 0.01). The ratio hNaDC1 mRNA/18sRNA in the patients with normal urine citrate was not significantly different from that in the controls (P > 0.05). The urine pH and urine sodium were significantly lower in the patients with hypocitraturia than in the other two groups. The levels of urine calcium and urine oxalate were significantly higher in the patients with hypocitraturia than in the controls, and were not different from those in the patients with normal urine citrate. CONCLUSION: The upregulation of hNaDC1 mRNA and protein abundance in the kidney may be an important cause of hypocitraturia, which might be related with the occurrence and recurrence of nephrolithiasis.

Adult↗

PubMed2001

Radiation induced apoptosis in ataxia telangiectasia homozygote, heterozygote and normal cells.

Recent reports suggest that the radiation-induced, p53-dependent, apoptotic response is aberrant in ataxia telangiectasia (AT) cells. We investigated the possibility that an aberrant apoptotic response to ionizing radiation may also be the characteristic of AT heterozygotes and may facilitate in discriminating AT heterozygotes from the general population. Log phase, Epstein Barr virus (EBV) transformed lymphoblastoid cell lines and primary lymphocytes from three AT families were irradiated and the apoptotic response at 30h post radiation was measured by flow cytometry using TUNEL and hypodiploid methods. Our results show that the apoptotic response of AT homozygote (ATM-/-), AT heterozygote (ATM+/-) and normal cells (ATM+/+) to ionizing radiation, measured by the hypodiploid and TUNEL methods using flow cytometry, is dose and time dependent. Furthermore, this response is paradoxical in that ATM (-/-) lymphoblastoid cells were characterized by a reduced post radiation apoptotic response compared to their normal counterparts. Heterozygote (ATM+/-) lymphoblastoid cells displayed an intermediate response to ionizing radiation. In contrast, primary, non-transformed AT cells exhibited the same apoptotic response as their normal counterparts. Our results thus indicate that pre-radiation, EBV-transformed, lymphoblastoid cell lines from individual families may be useful in discriminating ATM status, but patient-derived, primary AT homozygous, heterozygous and normal primary cultured lymphocytes cannot be discriminated by this assay.

Apoptosis↗

PubMed2001

Identification and characterization of S2V, a novel putative siglec that contains two V set Ig-like domains and recruits protein-tyrosine phosphatases SHPs.

We describe the molecular cloning and characterization of S2V, a novel sialic acid binding immunoglobulin-like lectin. The cDNA of S2V encodes a type 1 transmembrane protein with four extracellular immunoglobulin-like (Ig-like) domains and a cytoplasmic tail bearing a typical immunoreceptor tyrosine-based inhibitory motif (ITIM) and an ITIM-like motif. A unique feature of S2V is the presence of two V-set Ig-like domains responsible for the binding to sialic acid, whereas all other known siglecs possess only one. S2V is predominantly expressed in macrophage. In vivo S2V was tyrosine-phosphorylated when co-expressed with exogenous c-Src kinase. Upon tyrosine phosphorylation, S2V recruits both Src homology 2 (SH2) domain-containing protein-tyrosine phosphatases SHP-1 and SHP-2, two important inhibitory regulators of immunoreceptor signal transduction. These findings suggest that S2V is involved in the negative regulation of the signaling in macrophage by functioning as an inhibitory receptor. When expressed in COS-7 cells, S2V was able to mediate sialic acid-dependent binding to human red blood cells, suggesting that S2V may function through cell-cell interaction.

Amino Acid Sequence↗

PubMed2001

[Transporting into the kidney of medications injected into the renal adipose capsules of rats].

OBJECTIVE: To study the possibility of transporting into the renal tissue of medications by intrarenal adipose capsule injection (IC). METHODS: 1. Methylene blue (MB) was injected into the renal adipose capsule of 18 male healthy SD rats, and normal saline was injected into the renal adipose capsule at the side as control. Both kidneys taken out 1 - 24 hours after the injection, frozen slices were made to observe the transport of MB. 2. Salvia miltiorrhizae (SM) was injected into both renal adipose capsule of 18 male healthy SD rats. 48 healthy male SD rats were randomly divided into two groups, Tetramethylpyrazine (20 mg) was injected into per renal adipose capsule of the rats in one group and 40 mg Tetramethylpyrazine (TP) was injected into the veins of the rats in another group. 64 SD rats were randomly divided into two groups, methylprednisolone sodium succinate (25 mg/kg) was injected into per renal adipose capsule of the rats in one group and 50 mg/kg methylprednisolone (MP) sodium succinate was injected into the veins of the rats in another group. At different time, both kidneys and blood samples of all the rats were taken out. The contents of the three medications inside renal tissue and its blood samples were individually detected by HPLC. RESULTS: The peak values in the renal tissue of MB, SM, TP, MP were successively 6 h, 24 h (36 mg/g +/- 18 mg/g), 12 h (2 288 microgram/g +/- 236 microgram/g) and 1 h (120 microgram/g +/- 16 microgram/g) after IC. The medicine diffusing into the kidney can maintain longer time in IC group. CONCLUSION: The renal adipose capsule can be acted as the place of medicine storing and releasing into the kidney. The medicine diffusing into the kidney can attain higher concentration and maintain longer time. IC is a feasible method of local renal ad ministration with much less side effects.

Adipose Tissue↗

PubMed2001

mSiglec-E, a novel mouse CD33-related siglec (sialic acid-binding immunoglobulin-like lectin) that recruits Src homology 2 (SH2)-domain-containing protein tyrosine phosphatases SHP-1 and SHP-2.

The sialic acid-binding immunoglobulin-like lectins (siglecs) represent a recently defined distinct subset of the immunoglobulin superfamily. By using the Src homology 2 (SH2)-domain-containing protein tyrosine phosphatase SHP-1 as bait in a yeast two-hybrid screen, we have identified a new member of the mouse siglec family, mSiglec-E. The mSiglec-E cDNA encodes a protein of 467 amino acids that contains three extracellular immunoglobulin-like domains, a transmembrane region and a cytoplasmic tail bearing two immunoreceptor tyrosine-based inhibitory motifs (ITIMs). mSiglec-E is highly expressed in mouse spleen, a tissue rich in leucocytes. The ITIMs of mSiglec-E can recruit SHP-1 and SHP-2, two inhibitory regulators of immunoreceptor signal transduction. This suggests that the function of mSiglec-E is probably an involvement in haematopoietic cells and the immune system as an inhibitory receptor. When expressed in COS-7 cells, mSiglec-E was able to mediate sialic acid-dependent binding to human red blood cells, suggesting that mSiglec-E may function through cell-cell interactions. In comparison with the known members of the siglec family, mSiglec-E exhibits a high degree of sequence similarity to both human siglec-7 and siglec-9. The gene encoding mSiglec-E is localized in the same chromosome as that encoding mouse CD33. Phylogenetic analysis reveals that neither mouse mSiglec-E nor CD33 shows a clear relationship with any human siglecs so far identified.

Amino Acid Sequence↗

PubMed2001

The neurotoxic prion peptide fragment PrP(106-126) is a chemotactic agonist for the G protein-coupled receptor formyl peptide receptor-like 1.

Prion diseases are transmissible and fatal neurodegenerative disorders which involve infiltration and activation of mononuclear phagocytes at the brain lesions. A 20-aa acid fragment of the human cellular prion protein, PrP(106-126), was reported to mimic the biological activity of the pathologic isoform of prion and activates mononuclear phagocytes. The cell surface receptor(s) mediating the activity of PrP(106-126) is unknown. In this study, we show that PrP(106-126) is chemotactic for human monocytes through the use of a G protein-coupled receptor formyl peptide receptor-like 1 (FPRL1), which has been reported to interact with a diverse array of exogenous or endogenous ligands. Upon stimulation by PrP(106-126), FPRL1 underwent a rapid internalization and, furthermore, PrP(106-126) enhanced monocyte production of proinflammatory cytokines, which was inhibited by pertussis toxin. Thus, FPRL1 may act as a "pattern recognition" receptor that interacts with multiple pathologic agents and may be involved in the proinflammatory process of prion diseases.

Animals↗

PubMed2001

[Analysis of the polymorphisms of the AACT, ERAB and NACP genes in 15 patients with Alzheimer's disease].

OBJECTIVE: To analyze the polymorphisms of the AACT, ERAB and NACP genes in Han Chinese Alzheimer's disease (AD) patients. METHODS: Denaturant gradient gel electrophoresis (DGGE) was used to scan all DNA fragments of 3 genes mentioned above in AD group (15 cases) and elderly control group (241 cases). RESULTS: A25G and G39A substitutions were found in the AACT gene. The gene frequency of A25G was 80% in the AD group and 47% in the control group (P < 0.05). The gene frequency of G39A genotype was 13% in the AD group and 0.4% in the control group (P < 0.01). The allele (39) frequencies were also significantly different between the two groups (P < 0.01). We did not find any points with polymorphism in the ERAB and NACP genes. CONCLUSION: A25G and G39A substitutions in the AACT gene are probably one of the risk factors to AD in Han Chinese.

3-Hydroxyacyl CoA Dehydrogenases↗

PubMed2001

The magnesium-ene cyclization stereochemically directed by an allylic oxyanionic group and its application to a highly stereoselective synthesis of (+/-)-matatabiether. Allylmagnesium compounds by reductive magnesiation of allyl phenyl sulfides.

The first example of a magnesium-ene cyclization stereochemically directed by an allylic oxyanionic group is demonstrated by a highly stereoselective synthesis of the bicyclic terpene matatabiether 10. The synthetic method is particularly valuable, not only because of the stereochemical control and the utility of the versatile hydroxyl group introduced into the product, but also because the precursor of the allylmagnesium is an allyl phenyl sulfide, which is more stable and more easily prepared in a connective fashion than the usual allyl halide precursor. Since the presence of lithium ions encourages undesirable proton transfer to the cyclized organometallic and is detrimental to the stereochemical control, the conversion of the allylic thioether to the allylmagnesium utilizes a lithium-free method involving direct reductive magnesiation in the presence of the magnesium-anthracene complex.

Journal Article↗