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Biomedical subjects

C B Liu

Publications and source records attributed to C B Liu.

At least 19 recordsLinked to original sources
PubMed2001

A comparative study of light transmission aggregometry and automated bedside platelet function assays in patients undergoing percutaneous coronary intervention and receiving abciximab, eptifibatide, or tirofiban.

Platelet inhibition is central to the efficacy of glycoprotein (GP) IIb-IIIa antagonist therapy, but is not routinely measured during percutaneous coronary intervention (PCI). Data directly comparing the antiplatelet effects of these agents are also limited. Therefore, we compared ex vivo platelet function by standard light transmission aggregometry (LTA) and two automated bedside platelet function assays in 36 patients undergoing PCI with GP IIb-IIIa inhibitors. At baseline and 10 min following clinically recommended bolus and infusion of abciximab (0.25 mg/kg, 0.125 microg/kg/min), eptifibatide (180 microg/kg, 2 microg/kg/min), or tirofiban (10 microg/kg, 0.1 microg/kg/min), we measured 20 microM ADP- and 1.9 mg/mL collagen-induced platelet aggregation using LTA. Platelet function was also assessed using the bedside Accumetrics Ultegra-Rapid Platelet Function Assay (RPFA) and the Xylum Clot Signature Analyzer (CSA). The degree of platelet inhibition, as assessed by LTA, varied significantly between the clinically recommended doses of these GP IIb-IIIa antagonists. RPFA measurements agreed closely with LTA for abciximab, but tended to overestimate the degree of platelet inhibition for small molecules. CSA demonstrated profoundly inhibited shear-induced platelet function, but lacked sensitivity to discriminate between agents. These findings may have implications for the results of trials comparing the efficacy of these agents in patients undergoing PCI.

Abciximab↗
PubMed2001

Supracondylar extension fracture of the humerus in children. Manipulative reduction, immobilisation and fixation using a U-shaped plaster slab with the elbow in full extension.

We present a method of manipulative reduction, immobilisation and fixation using a U-shaped plaster with the elbow in extension for extension-type supracondylar fractures of the humerus in children. When the elbow is in full extension, both the extensor and the flexor muscles are neutralised during manipulative reduction and the carrying angle can be easily assessed thus preventing cubitus varus, the most common complication. In order to evaluate the efficiency of this method, we compared the clinical results of the new method with those of conventional treatment. In a group of 95 children who sustained an extension-type supracondylar fracture of the humerus, 49 were treated by the new method and 46 by the conventional method, reduction and immobilisation in a plaster slab with the elbow in flexion. Reduction and immobilisation were easily achieved and reliably maintained by one manipulation for all the children treated by the new method. In 12 children treated by the conventional method, the initial reduction failed and in seven secondary displacement of the distal fragment occurred during the period of immobilisation in plaster. All required a second or third manipulation. Of the 46 children, 28 (60.9%) had developed cubitus varus at a mean follow-up of 4.6 years when treated by the conventional method. None of the children treated by the new method developed cubitus varus. The mean score, according to the Hospital for Special Surgery (HSS) elbow scoring system, was 91 points using the new method and 78 with the conventional method. The results were statistically significant with regard to the incidence of cubitus varus and the elbow score (p < 0.01) suggesting that the new method is reliable and gives a satisfactory outcome.

Adolescent↗
PubMed2001

[Cerebral arterial aneurysm in a child with acquired immunodeficiency syndrome: case report].

Cerebral aneurysmal arteriopathy of the circle of Willis is an uncommon manifestation of acquired human immunodeficiency virus (HIV) infection and up to now only 15 cases have been published in the literature. For this reason we add our experience of this rare case, and review the most important aspects related to this entity. The patient is a 6 year old male with perinatal transmitted AIDS, tetraparethic, developed symptoms characterized by episodes of dystonic postures. The computed tomography of the brain showed aneurismal arteriopathy of the circle of Willis. He had a previous normal examination. The review of the literature shows the pathological abnormalities of the affected vessels are mainly medial fibrosis, with destruction of the internal elastic lamina and intimal hyperplasia. The etiology for the vasculitis is unknown. Varicela zoster virus, as well as HIV by itself, can be related to the physiopathology of the vasculitis. On conclusion, it can be said that although uncommon, such complications are of great importance by the fact that the patients with vascular aneurismal arteriopathy are in high risk for vascular accidents, and once a diagnosis was made, death occurs in less than 6 months, according to the literature.

Acquired Immunodeficiency Syndrome↗
PubMed2001

[Prevalence of mutants in the determinant region of hepatitis B surface antigen among Chinese carriers after receiving only active postexposure immunoprophylaxis].

OBJECTIVE: To determine the frequency of hepatitis B surface antigen (HBsAg) mutations in the alpha determinant region among children who developed chronic hepatitis B virus (HBV) infection after receiving only active postexposure immunoprophylaxis. METHODS: HBsAg mutations were determined by PCR-directed nucleotide sequencing and sequence-specific solid-phase PCR analysis(SS-SPPCR) for 97 Chinese carrier cases after hepatitis B vaccination, for 88 children born aged women controls, and for 95 population based children controls. RESULTS: Prevalence of amino acid substitutions as detected by direct sequencing among carrier cases, women controls, and children controls were 30.9%, 10.2%, and 5.3%, respectively. The most frequent amino acid substitutions observed were at residues 145, 126, and 133. However, there was no difference in the prevalence of 145 and 126 amino acid mutants as detected by a sensitive SS-SPPCR method between carrier cases and controls. The prevalence of 145 Arg and 145 Ala mutants that were detected by SS-SPPCR was 39.2%, 33.0% and 32.6% among carrier cases, women controls, and children controls, respectively. The total odds ratio was 5.41 for mutants detected by direct sequencing. Odds ratio were 34.55 and 33.39 among adw2 subtype and genotype B subjects for mutants detected by direct sequencing, respectively. CONCLUSIONS: The results show that hepatitis B virus mutants in the determinant are fairly consistent observed but without immune selective pressures; HBV variant strains may pre-existent as minor quasispecies. The prevalence of mutants is related to HBV subtypes and genotypes.

Adolescent↗
PubMed2001

[Long-term efficacy of vaccination against hepatitis B in newborns: 13 years' follow-up].

OBJECTIVE: To evaluate long-term efficacy of hepatitis B vaccination in newborns. METHODS: In the past 13 years we followed up the children who had been immunized with hepatitis B vaccine at birth in 1986 every other year. At each follow-up visit, every child was tested for HBsAg, anti-HBs and anti-HBc. RESULTS: HBsAg positive rate of these birth cohort was low (range between 0.46% and 0.98%) during 13 years' follow-up. Long-term efficacy of the vaccination in preventing HBsAg carriage was confirmed. CONCLUSIONS: Thirteen years later no booster was after needed.

Female↗
PubMed2001

[Acceptance check and quality control of SPECT].

This paper explains the testing of SPECT, especially the new SPECT with double digital detector and spiral scanning frames that has been introduced to China recently, in the acceptance check, proceeding from the physical functions of the system to its mechanical functions, to the NEMA standard functions, and then to the computer hardware specified in the contract. A brief introduction is also given of the quality control of SPECT in terms of its spatial resolution, energy resolution, spatial linearity, sensitivity, and center of rotation.

Quality Control↗
PubMed2000

Analysis of mechanisms involved in the prevention of gamma irradiation-induced apoptosis by hGM-CSF.

Human granulocyte-macrophage colony-stimulating factor (hGM-CSF) induces proliferation and sustains viability of the mouse interleukin (IL)-3 dependent lymphoid cell line BA/F3 expressing the hGM-CSF receptor. Caspase-3 like enzyme activity and DNA fragmentation were augmented by depletion of this factor from the cell, and exposure to gamma irradiation accelerated kinetics of these events. Anti gamma irradiation-induced apoptosis occurred through various mutant GM-CSF receptors and only the box1 region was essential while the C terminal region, including tyrosine residues which are required for MAPK cascade activation, was dispensable. Consistent with this notion, the addition of PD98059 had no effect on this activity thereby indicating that activation of MAPK is not essential for the activity. As expected, gamma irradiation increased p53 protein and bax mRNA levels and the presence of hGM-CSF dramatically modulated bax/bcl-X(L) ratio. The PI-3K specific inhibitor wortmannin did not affect hGM-CSF dependent anti gamma irradiation induced apoptosis nor bcl-X(L) induction, thus bcl-X(L) but not PI-3K pathway seems to be involved in hGM-CSF dependent anti gamma irradiation-induced apoptosis. It is well documented that the boxl region is essential for GM-CSF dependent activation of JAK2 and JAK2 specific inhibitor AG490 suppressed anti gamma, irradiation-induced apoptosis by hGM-CSF. An artificial JAK2 activating molecule in which extracellular and the transmembrane of beta(c) fused with whole JAK2 can sustain BA/F3 cells survival and proliferation mIL-3 independently, but these cells are susceptible to gamma irradiation. Furthermore GyrB/Jak2, which can activate STAT5 but not the MAPK cascade nor survival of BA/F3 cells, also could not prevent gamma irradiation-induced apoptosis. Although JAK2 is essential for hGM-CSF dependent anti gamma irradiation-induced apoptosis, it appeared that JAK2 does not seem sufficient for the activity.

Animals↗
PubMed1999

Constitutive activation of JAK2 confers murine interleukin-3-independent survival and proliferation of BA/F3 cells.

The Janus tyrosine kinase 2 (JAK2) plays an essential role of cytokine receptor signaling, including that of the human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor. We reported earlier that the activation of JAK2 is essential for all the examined signals induced by human GM-CSF through the box1 region of betac, such as promotion of cell survival and proliferation. To elucidate the role of JAK2 in cell survival and proliferation, we generated an artificial activation system by constructing a chimeric molecule (beta/JAK2) consisting of betac extracellular and transmembrane regions fused with JAK2, and we analyzed various signaling events in interleukin-3-dependent mouse pro-B cell, BA/F3. The beta/JAK2 was constitutively phosphorylated in the absence of human GM-CSF and murine interleukin-3, and this led to proliferation and cell survival. Western blot analysis showed that STAT5, Shc, and SHP-2 were not phosphorylated in the cells, and the consistent activation of beta-casein and c-fos promoters was not enhanced. In contrast, c-myc transcription was constitutively activated. We propose that the activation of beta/JAK2 suffices for survival and proliferation and that the activation of STAT5 and mitogen-activated protein kinase cascade is not required for these activities in BA/F3 cells.

Animals↗
PubMed1999

Anatomic basis of iliac crest flap pedicled on the iliolumbar artery.

This paper presents the anatomy and clinical applications of an iliac crest flap pedicled on the iliolumbar artery. 54 iliolumbar arteries were filled with pink plastic in 27 adult cadavers. Their origin, course and branches, and the surroundings were investigated, and the external diameter, length of segments and terminal distribution were measured. The iliolumbar artery was constant, but with a few variations. Its length was 7.0 +/- 3.9 cm, and the outer diameter 2.0 +/- 0.4 mm at the lateral edge of the psoas major muscle. Based on the anatomic findings, the surgical technique for a bone flap based on the iliolumbar artery was designed. Its clinical applications included both free bone grafting (in 2 patients) and pedicled bone transfer (in another 2 patients). The clinical results were satisfactory. The iliac crest flap pedicled on the iliolumbar artery is a reliable bone flap for clinical usage.

Adult↗
PubMed1999

Recombinant adenovirus vectors for cytokine gene therapy in mice.

BACKGROUND: Adenoviruses have several specific features useful for gene therapy. They infect various lineages of cells irrespective of cell cycle status. However, the exact mechanism of their infection and in vivo kinetics as a gene expression vector have not been elucidated. OBJECTIVE: Using adenovirus vectors expressing marker genes, we examined the infectivity of these vectors (including cellular and tissue tropism), the duration and intensity of transgene expression, and the side effects. METHODS: Various cells were infected with adenovirus expressing LacZ gene at various doses, and beta-galactosidase activity was measured and compared in relation with dose, time course, and cellular vitronectin receptor. Mice were injected with adenoviruses expressing LacZ, luciferase and GM-CSF, and in vivo gene expression was examined. RESULTS: Adenovirus infection induced viral dose-dependent transgene expression that persisted for 2 weeks. Adherent cells were infected much more efficiently than nonadherent cells, probably because the former expressed much higher levels of the vitronectin receptor, one of the main receptors for adenovirus. Studies performed in mice with luciferase-expressing adenovirus revealed that the liver was the main target organ after intravenous injection and showed that the intravenous route was superior to other routes with regard to transgene expression. After intravenous injection of adenovirus expressing human GM-CSF, there was a transient and dose-dependent increase in the serum level of this cytokine. Administration of adenovirus expressing mouse GM-CSF enhanced hematopoiesis in the spleen and bone marrow. CONCLUSION: These results indicated that adenoviruses can be used for in vivo cytokine gene therapy but suggested the necessity of taking into consideration the route of administration, the duration of transgene expression, the toxic dose, and host immune reactions.

Adenoviridae↗
PubMed1995

Total body bone mineral content in small-for-gestational -age, appropriate-for-gestational -age, large-for-gestational -age term infants and appropriate-for-gestational -age preterm infants.

BACKGROUND: Metabolic bone disease is a recognized complication in very low birth weight infants. Inadequate postnatal intake of calcium and phosphorus is probably important in the pathogenesis of bone disease in the newborn. A few studies have shown lower bone mineral content at birth in small for gestational age (SGA) than in appropriate for gestational age (AGA) infants. The present study was designed to compare total body bone mineral (TBBM) content in AGA, SGA, and large for gestational age (LGA) term infants. Also, it was designed to evaluate extrauterine changes in TBBM in preterm infants. METHODS: Ten SGA [mean +/- S.D. birth weight (B.W.) was 1.7 +/- 0.2 Kg, gestational age (G.A.), 39.0 +/- 0.8 weeks], ten AGA (B.W.; 3.3 +/- 0.4 Kg; G.A.: 39.3 +/- 1.4 weeks), ten LGA (B.W.: 4.4 +/- 0.3 Kg; G.A.: 40.4 +/- 0.9 weeks) term infants and ten AGA preterm infants (B.W.: 1.6 +/- 0.3 Kg; G.A.: 31.9 +/- 1.9 weeks) were enrolled in this study. TBBM content was measured using dual-photon-absorptiometry at 1 week postnatally in SGA, AGA, LGA term infants and in preterm infants at 1, 6, 12 weeks postnatally. Serum total calcium, phosphorus, magnesium, alkaline phosphatase activity (alk-p), parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OHD) and urinary calcium, phosphorus, creatinine were measured at 1 week postnatally in all studied infants and 6, 12 weeks, postnatally in preterm infants. Preterm and SGA term infants received premature formula enriched with calcium, phosphorus and vitamin D. RESULTS: There was no significant difference (p > 0.05) in serum calcium, phosphorus, magnesium, alk-p, PTH, 25-OHD and urinary calcium, phosphorus, creatinine values among SGA, AGA and LGA term infants at one week of age. Also, there was no significant difference in serum biochemical values in preterm infants at 1, 6, 12 weeks postnatally. Significantly lower (p < 0.05) urinary phosphorus values were found in preterm than in term infants. TBBM content was lower (p < 0.05) in SGA term infants than in AGA and LGA term infants. Premature infants had lower (p < 0.01) TBBM values than term AGA infants; however, TBBM values increase with postnatal age in preterm infants. CONCLUSIONS: Biochemical or marked radiological evidence of metabolic bone disease did not develop in any of the studied preterm infants. It appears that feeding permature infants with formula enriched with phosphorus, calcium and vitamin D may provide sufficient mineral for bone mineralization.

Birth Weight↗
PubMed1994

cDNA cloning of c33-c antigen gene derived from NS3 region of Chinese HCV genome, expression in Escherichia coli and development of HCV EIA second-generation diagnostic kit.

A cDNA fragment of about 860 bp corresponding to the c33-c gene in the non-structural region 3 (NS3) of HCV genome was obtained from one plasma derived from a Chinese HCV carrier who came from Tai' an of Shandong Province, China by the application of reverse transcription (RT) and polymerase chain reaction (PCR) techniques. After the sequence of the cDNA fragment was determined and compared with the equivalent region of the HCV-I (HCV-US) and HCV-II (HCV-BK) genomes, the nucleotide/amino acid sequence homologies were found to be 79.2%/91.3%/ and 91.3%/93.9%, respectively. The prokaryotic expression vector pBV220 was employed for the overproduction of c33-c native recombinant protein in E. coli cells. The expression products were detected by enzyme-linked immunosorbent assay (ELISA) and Western blotting with antisera of chronic hepatitis C patients, and a molecular weight 31 kD of c33-c viral protein was shown to account for 14% of the total cellular soluble proteins. This product was extracted from the bacterial lysate by lysozyme, Triton X-100 and urea treatment, and purified through ion exchange chromatography. The purified c33-c protein combined with a branch peptide MAP-C-19 representing immunodominant epitopes on the nucleocapsid region of HCV genome was used to develop a Chinese HCV EIA 2nd-generation diagnostic kit for the detection of anti-HCV antibodies. Its specificity, sensitivity and reproducibility were all in keeping with the indexes of the national standard for the quality control of the HCV diagnostic kit. The agreement rate between our kit and Abbott company's HCV EIA second-generation diagnostic kit was 99.33%, and the identified rate of positive anti-HCV of our kit was 2% more than that of the Abbott company's kit.

Amino Acid Sequence↗
PubMed1994

Spontaneous rupture of the liver associated with pregnancy: a report of two cases.

Spontaneous rupture of the liver associated with pregnancy is a rare and grave complication, usually occurring in preeclampsia or eclampsia. Two cases of ruptured subcapsular hematoma of the right liver during pregnancy are reported. The first case was a 19-year-old woman who had suffered from epigastralgia and absent fetal heart beat in the 32nd week of gestation. The second case was a 31-year-old female who complained of nausea and right upper quadrant pain in the 35th week of pregnancy. Both had preeclampsia, and developed shock with disseminated intravascular coagulation soon after admission. Both received surgery and were found to have ruptured hematoma over the right liver. Finally, the first patient died of renal failure, but the second survived because preoperative diagnosis had been exact. Greater suspicion, then awareness of diagnosis can lead to better timing of surgery and an improved prognosis for mother and child.

Adult↗
PubMed1991

Epidemiology of hepatitis E in China.

A total of 9 hepatitis E epidemics have been documented in China since 1982. Five of them were waterborne and four foodborne, and they occurred in 6 of 30 provinces or autonomous regions in the country. The disease most frequently affects young adults, with fewer cases in children and the elderly. A relative male excess of cases has been observed. However, the fatality rate in female patients with hepatitis E is significantly higher than in males. The disease has a distinctive autumn seasonality in endemic areas. A peak of fecal excretion of hepatitis E virus is found at the late incubation period and early acute phase. The incubation period of the disease ranges from 15 to 75 days, with a mean of 36 days. A randomized double-blind and controlled study showed that human immune serum globulin had no prophylactic effects on hepatitis E.

Adolescent↗
PubMed1991

A serological study of hepatitis C infection in plasmapheresis donors.

An epidemic of parenterally transmitted non-A, non-B hepatitis (PT-NANBH) occurred in plasmapheresis donors in Guan County, Hebei Province, China, in 1985. PT-NANBH was diagnosed by epidemiological studies and serological exclusion of HAV, HBV, CMV and EBV infections. Recently, 163 sera samples of 108 patients with PT-NANBH and 65 sera samples of 49 cases with elevated alanine aminotransferase (ALT) levels collected during the epidemic were tested by anti-HCV EIA (Chiron C100). The positive rates of anti-HCV in these two groups were 89.8% (97/108) and 93.9% (46/49), averaging 90.8%. The figures increased with the course of illness and persistance of ALT elevation, i.e., 17.6% and 55.6% within 1 month, 88.9% and 87.5% at 6 months and 100% and 100% after 2 years. Five patients with PT-NANBH and 1 with elevated ALT levels were followed up for 3 to 4 years. We demonstrated that anti-HCV remained positive after the disease had resolved and ALT levels had normalized.

Alanine Transaminase↗