A novel compound heterozygous mutation in the F13A gene causing hereditary factor XIII deficiency in a Chinese family.
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Adolescent↗
Biomedical subjects
N Dong
Publications and source records attributed to N Dong.
ADAMTS-13 plasma level determination uncovers antigen absence in acquired thrombotic thrombocytopenic purpura and ethnic differences.
BACKGROUND: The recently discovered plasma enzyme ADAMTS-13 cleaves the A2-domain of von Willebrand factor (VWF). A defective cleaving protease results in unusually large VWF multimers, which cause thrombotic thrombocytopenic purpura (TTP). AIM: Analysis of the ADAMTS-13 antigen levels in TTP patients compared with normal donors. METHODS: An antigen ELISA test was built, based on high affinity anti-ADAMTS-13 monoclonal antibodies, which were generated using genetic immunization. RESULTS: Specificity of the ADAMTS-13 antigen test was confirmed, as (i) plasma from a patient with acquired TTP but presenting without inhibitor did not contain antigen and (ii) the binding of recombinant ADAMTS-13 was inhibited by increasing amounts of normal plasma. The assay is sensitive as it can detect antigen levels as low as 1.6% of normal. The concentration in normal pooled human plasma was determined (1.03 +/- 0.15 microg mL(-1)) and arbitrarily set to 1 U mL(-1). The antigen levels in congenital TTP samples (34 +/- 21 mU mL(-1), n = 2), as well as in samples from patients with acquired TTP (231 +/- 287 mU mL(-1), n = 11), were clearly reduced when compared with normal Caucasian donors (951 +/- 206 mU mL(-1), n = 16). Remarkably, normal Chinese donors have a significantly lower antigen titer (601 +/- 129 mU mL(-1), n = 15), when compared with normal Caucasians. CONCLUSIONS: Our results show that acquired TTP patients suffer mainly from ADAMTS-13 antigen depletion, thereby indicating the importance of ADAMTS-13 antigen determination in diagnosis and patient follow-up.
ADAM Proteins↗
[The effect of pentoxifylline on endotoxin-induced biopterin formation in rabbits].
OBJECTIVE: To observe the potential effect of pentoxifylline on endotoxin-mediated biopterin (tetrahydrobiopterin and more oxidized species) formation and systemic hemodynamics. METHODS: Rabbits were subjected to endotoxic shock induced by a bolus intravenous injection of E. coli O26B6 lipopolysaccharide (400 microg/kg). 28 animals were divided into sham-operation group (n = 8), endotoxic shock group (n = 10), and pentoxifylline-treated group (n = 10). Plasma biopterin and tumor necrosis factor-alpha (TNF) levels, and guanosine triphosphate cyclohydrolase I (GTP-CHI) activity in tissues were determined at various intervals. RESULTS: Treatment with pentoxifylline significantly decreased plasma biopterin and TNF levels at 2 to 8 hours after endotoxin challenge (P < 0.05, P < 0.01), and inhibited GTP-CHI activities in the liver, lung, and myocardial tissues (P < 0.05). Meanwhile, systemic hemodynamic parameters, including mean arterial pressure, cardiac output, and total peripheral resistance, in the treatment group were much higher than those in the endotoxic shock group. CONCLUSIONS: These data suggest that early treatment with pentoxifylline can effectively inhibit endotoxin-induced biopterin synthesis and release, and markedly improve systemic hemodynamics during septic shock.
Animals↗
[Determination of Pericarpium papaveris in foods accompanied with some fragrant substances by high performance liquid chromatography].
An HPLC method for the determination of Pericarpium papaveris in foods accompanied with some fragrant substances is described. The Pericarpium papaveris in food was extracted in alkaline condition with CHCl3-C2H5OH(9:1, V/V) and analyzed by reversed-phase HPLC by using a YWG C6H5 column and acetonitrile-methanol-water as mobile phase. The calibration curves of papaverine, morphine and codeine were linear in the range of 1.2 mg/L-100 mg/L and the mean recoveries were from 79.3% to 86.1%. The method has a good specificity and accuracy.
Chromatography, High Pressure Liquid↗
Factors affecting the degradation rate of poly(lactide-co-glycolide) microspheres in vivo and in vitro.
The purpose of this work was to study the degradation of poly(lactide-co-glycolide) (PLG) microspheres in vivo and in vitro. Degradation rate constants were determined by measuring the polymer molecular weight as a function of time by gel-permeation chromatography. The effects of PLG chemistry and the effects of encapsulating the sparingly soluble salt zinc carbonate and the protein recombinant human growth hormone (rhGH) on the degradation rate were assessed. It was found that in vivo degradation was faster than in vitro degradation. In addition, different types of PLGs were found to degrade at different rates depending on the chemistry of the polymer end group and, to a lesser extent, the molecular weight. Finally, zinc carbonate was found to retard the degradation of some PLGs. These degradation studies have proved valuable in the design of sustained release microsphere products.
Animals↗
[Measurement of liver volume and its clinical significance in cirrhotic patients].
OBJECTIVE: To evaluate whether, preoperative measurement of liver volume is of value to the evaluation of tolerance to operation and long-term prognosis in cirrhotic patients with portal hypertension. METHODS: We assessed liver volume in 18 cirrhotics and 31 noncirrhotic controls with 3-dimensional shaded surface display by CT twin. RESULTS: The liver volume in controls was positively correlated to the height (r = 0.42, P < 0.05). The average of liver volume in controls was (1 070.68 +/- 227.52) cm(3) and was different from that of cirrhotics (797.02 +/- 135.11) cm(3) (P < 0.05). Liver volume of cirrhotic patients with portal hypertension was related to their Child classification. The liver volume of patients in Child C group was significantly smaller than that of patients of Child B group. CONCLUSIONS: The patients with smaller liver volume are likely complicated by encephalopathy after shunting procedure. However, the liver volume is not significantly correlated with portal blood flux and portosystemic shunt index.
Adult↗
A large-scale process to produce microencapsulated proteins.
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Animals↗
[Clinical observation of splenectomy on chronic idiopathic thrombocytopenic purpura in 63 patients].
OBJECTIVES: To investigate the effectiveness of splenectomy in patients with idiopathic thrombocytopenic purpura who failed to respond to conservative management. METHOD: Sixty-three patients were treated with splenectomy and followed up for 2 months to 16 years (average 4.7 years). RESULT: The patients had symptoms of bleeding and their platelet count on average was 24 x 10(9)/L. The first, 3rd, 5th and 7th day after operation, the average platelet count was 110 x 10(9)/L, 202 x 10(9)/L, 251 x 10(9)/L and 246 x 10(9)/L. Their platelet recovered to normal during a week in 51 cases (80.9%). The total effective rate was 86.9% after follow-up for 2 months. The recurrence rate was 17.9% in 39 cases after follow-up for longtime. CONCLUSIONS: The curative effect of splenectomy is better in children than in adults. In patients with increased platelet have a favourable prognosis. Splenectomy is safe and effective in the treatment of idiopathic thrombocytopenic purpura.
Adolescent↗
Estimating extracellular concentrations of dopamine and 3,4-dihydroxyphenylacetic acid in nucleus accumbens and striatum using microdialysis: relationships between in vitro and in vivo recoveries.
It is common practice in microdialysis studies for probes to be "calibrated" in artificial CSF and in vitro recoveries determined for all substances to be measured in vivo. Dialysate concentrations of such substances are then "corrected" for in vitro recoveries to provide "estimates" of extracellular concentrations. At least for dopamine, in vitro and in vivo recoveries are significantly different and, therefore, an estimate of extracellular dopamine based on correction for in vitro recovery is likely to be erroneous. Generally, however, the relative relationships of such estimates among animals are of interest rather than the "true" extracellular values. Such relationships would be valid to the extent that estimated values are correlated with or predictive of true values. Using the "no net flux" procedure, the present study sought to determine, for both dopamine and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC), whether in vitro and in vivo recoveries would correlate with each other as well as whether respective estimated and true (no net flux) values of these substances would correlate with each other. Probes (3 mm; BAS/CMed MF-5393), previously calibrated, were lowered into both the nucleus accumbens and striatum of freely moving rats the day before sample collection was begun. In vitro and in vivo recoveries were not significantly correlated (r = 0.1-0.3), for either dopamine or DOPAC. For both dopamine and DOPAC, however, there were significant correlations (r = 0.7-0.8) between estimated and true values. Surprisingly, when using these commercial probes, absolute dialysate levels for both substances were even better correlated (r = 0.9-0.95) with true values.(ABSTRACT TRUNCATED AT 250 WORDS)
3,4-Dihydroxyphenylacetic Acid↗
Wear and corrosion of modular interfaces in total hip replacements.
Modular components allow for the customization of hip replacements to the individual patient. Modular head-neck components allow for mixed material systems to minimize polyethylene wear as well as provide the ability to vary neck length and head size independent of the stem. Modular interfaces, however, result in an increased susceptibility to interface corrosion and wear debris generation. One hundred eight uncemented femoral stems with modular heads retrieved for reasons other than loosening with modular heads were examined for interface corrosion. In addition, in an effort to quantify the amount of wear debris generated at modular interfaces due to cyclic loading, mechanical testing and electrozone particle analysis was used to study various surface, material, and design combinations. Detectable degrees of corrosion were observed in ten of 29 (34.5%) mixed alloy systems and seven of 79 (9%) single alloy components at an average of 25 months in situ. There was no correlation between presence or extent of corrosion or surface damage with time in situ, initial diagnosis, reason for removal, age, or weight. Stems with corrosion were less likely to have bone ingrowth histologically. The results of mechanical testing showed a significant number of wear particles were generated by all head-neck combinations. The wear debris was almost totally in the size range less than 5 microns. As many as 2.5 million particles were generated the first million cycles loading, with as many as eight million particles generated at ten million cycles. The results indicate that surface preparation and material affect particle generation. Head-neck tolerance mismatch appears to be significantly variable in the number of particles generated.
Alloys↗
Local effects of ibogaine on extracellular levels of dopamine and its metabolites in nucleus accumbens and striatum: interactions with D-amphetamine.
Systemic administration of ibogaine (40 mg/kg, i.p.) has been reported to induce both acute (1-3 h) and persistent (19-20 h) changes in extracellular levels of dopamine and its metabolites in the nucleus accumbens and striatum. In the present study, local administration of ibogaine to the striatum and nucleus accumbens produced effects that mimicked both the acute and persistent effects of systemic administration: perfusion with high concentrations (200 and 400 microM) of ibogaine mimicked the acute effects (decreased extracellular dopamine levels and increased extracellular metabolite levels) whereas perfusion with a low concentration (10 microM) of ibogaine mimicked the persistent effects (decreased extracellular levels of DOPAC). These results indicate that ibogaine acts directly in brain regions containing dopaminergic nerve terminals and that long-lasting effects of systemically administered ibogaine might be mediated by persisting low levels of ibogaine. Locally administered ibogaine (10 microM) was also found to enhance the effects of systemically administered D-amphetamine (1.25 mg/kg, i.p.) on extracellular dopamine levels, and conversely, systemically administered ibogaine (40 mg/kg, i.p.; 19 h pretreatment) enhanced the effects of locally administered D-amphetamine (1-10 microM). These results indicate that, in addition to a metabolic mechanism implicated previously, a pharmacodynamic mechanism contributes to the interaction between ibogaine and D-amphetamine. The relevance of such mechanisms to claims regarding ibogaine's anti-addictive properties is unclear.
Animals↗