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Biomedical subjects

H P Chen

Publications and source records attributed to H P Chen.

At least 19 recordsLinked to original sources
PubMed2005

Diagnosis of human cytomegalovirus intrauterine infection using fetal cells from maternal blood.

OBJECTIVE: The sensitivity and specificity for the noninvasive prenatal diagnosis of human cytomegalovirus intrauterine infection were estimated by using isolating single fetal cells from maternal peripheral blood. METHODS: Micromanipulation techniques were employed to isolate single fetal nucleated erythroblasts from 273 maternal blood samples. SRY gene and HCMV-DNA in single fetal cells were detected by multiple primed in situ labeling (PRINS) from 76 HCMV-DNA positive samples of maternal peripheral blood. 273 samples of maternal peripheral blood were tested for SRY gene and HCMV-DNA in single fetal cells by primed extension preamplification (PEP) and polymerase chain reaction (PCR). RESULTS: The detection rate of fetal cells from maternal blood was 100% with micromanipulation techniques. The sensitivity of PRINS for SRY gene detection was 97.56% and its specificity was 100%. The sensitivity and specificity of PEP and PCR for SRY gene detection were 97.39% and 99.17%, respectively. The sensitivity of PRINS for HCMV-DNA detection was 92.68% and the specificity was 100%. The sensitivity and specificity of PEP and PCR for HCMV-DNA detection were 95.12%and 100%, respectively. CONCLUSION: The technique for noninvasive prenatal detection of intrauterine infection of HCMV using single fetal cells from maternal peripheral blood by using PRINS and PEP and PCR is more reliable than the CMV-DNA detection in peripheral maternal blood, amniocentesis or percutaneous umbilical blood sampling.

Cytomegalovirus↗
PubMed2004

Fetal origin of single nucleated erythroblasts and free DNA in the peripheral blood of pregnant women.

OBJECTIVES: To investigate the feasibility of using single fetal nucleated erythroblasts (FNRBCs) and free DNA in maternal blood for non-invasive prenatal diagnosis. METHODS: Single FNRBCs were isolated from 51 of 116 samples of maternal blood analyzed by micromanipulation after density gradient centrifugation. Furthermore, the nested polymerase chain reaction (PCR) method was used to amplify the SRY gene of single FNRBCs. Primer extension pre-amplification and nested PCR were used to amplify the SRY gene of the plasma DNA extracted from 65 samples of maternal blood. RESULTS: The detection rate of single FNRBCs was 90.20% (46/51). The concordance rates between real fetal sex and sex determined by amplification of the SRY gene from single cells and from free DNA analysis were 82.61% (38/46) and 90.77% (59/65), respectively. CONCLUSIONS: Single nucleated erythroblasts and free DNA in maternal blood are of fetal origin and can be valuable fetal material sources for non-invasive prenatal diagnosis.

Adult↗
PubMed2004

Study on the expression of angiotensin II (ANG II) receptor subtype 1 (AT1R) in the placenta of pregnancy-induced hypertension.

OBJECTIVE: To study the expression of angiotensin II (ANG II) receptor subtype 1 (AT(1)R) in the human placenta with pregnancy-induced hypertension (PIH). METHODS: Immunohistochemistry was used to detect the expression of AT(1)R in placental tissues of 30 patients with PIH and 10 patients with normal pregnancies (control group). The PIH tissues were further divided into 3 groups: mild PIH group, moderate PIH group and severe PIH group. Each group consisted of 10 patients. A high-resolution pathological image analysis system (HPIAS-1000) was used to determine the quantity of AT(1)R expression. RESULTS: The integral optical density and area of staining in the syncytiotrophoblast (STB) layer and villous endothelium of the placenta were significantly increased in PIH patients, in the moderate and severe PIH groups, as compared with the control group (P < 0.05), indicating that the expression of AT(1)R was highly increased in PIH. However, there was no significant difference between normal pregnancy and the mild PIH group (P > 0.05). Furthermore, statistically significant differences in AT(1)R expression were observed between mild, moderate and severe PIH groups (P < 0.05). CONCLUSION: The expression of AT(1)R is statistically significantly increased in the STB layer and villous endothelium of human placenta with PIH. Expression increases with the severity of the disease. Increased expression may be involved in the pathogenesis of PIH.

Adult↗
PubMed2004

C4d-positive acute humoral renal allograft rejection: rescue therapy by immunoadsorption in combination with tacrolimus and mycophenolate mofetil.

OBJECTIVE: We investigated the efficacy of immunoadsorption (IA) in combination with tacrolimus (FK506) and mycophenolate mofetil (MMF) rescue therapy for C4d-positive acute humoral rejection (AHR) of renal transplants. METHODS: Six of 185 cadaveric renal allograft recipients developed AHR at a mean of 4.8 +/- 0.8 days after the operation. C4d deposits were observed in peritubular capillaries (PTC) with accumulation of granulocytes. IA with staphylococcal protein A and FK506-MMF combination therapy were administered. RESULTS: After treatment with IA for 6.3 +/- 1.03 sessions combined with FK506 (0.14 to 0.16 mg.kg(-1).d(-1)) and MMF (1.5 g/d) therapy, renal function recovered in all the patients. The mean duration of treatment to a serum creatinine decrease was 14 +/- 2.9 days. The pre-IA panel reactive antibody reactivity (PRA) peaked at 50.2% +/- 6.1%, and was significantly reduced to 8.3% +/- 2.9% after IA. In four of six patients repeat allograft biopsy revealed a remission of AHR. With a mean follow-up of 18.8 +/- 5.46 months, patient and allograft survival are 100% and renal function remains stable with a mean serum creatinine of 1.2 +/- 0.22 mg/dL. CONCLUSION: The optimal treatment for alloantibody-mediated AHR remains uncertain. Our findings suggest that a therapeutic approach combining IA and FK506-MMF rescue improves the outcome of AHR.

Acute Disease↗
PubMed2004

The prevalence and spectrum of alpha and beta thalassaemia in Guangdong Province: implications for the future health burden and population screening.

AIM: Thalassaemia is a good candidate disease for control by preventive genetic programmes in developing countries. Accurate population frequency data are needed for planning the control of thalassaemia in the high risk Guangdong Province of southern China. METHODS: In total, 13397 consecutive samples from five geographical areas of Guangdong Province were analysed for both haematological and molecular parameters. RESULTS: There was a high prevalence of carriers of alpha thalassaemia (8.53%), beta thalassaemia (2.54%), and both alpha and beta thalassaemia (0.26%). Overall, 11.07% of the population in this area were heterozygous carriers of alpha and beta thalassaemia. The mutation spectrum of alpha and beta thalassaemia and its constitution were fully described in this area. This study reports the true prevalence of silent alpha thalassaemia in the southern China population for the first time. In addition, two novel mutations that give rise to alpha thalassaemia, one deletion resulting in beta thalassaemia, and a rare deletion (--(THAI) allele) previously unreported in mainland China were detected. The frequency of the most common mutation, the Southeast Asian type of deletion (--(SEA), accounting for 48.54% of all alpha thalassaemias) was similar to the total of two alpha(+) thalassaemia deletions (-alpha(3.7) and -alpha(4.2), accounting for 47.49% of alpha thalassaemia). CONCLUSION: Both alpha and beta thalassaemia are widely distributed in Guangdong Province of China. The knowledge gained in this study will enable the projected number of pregnancies at risk to be estimated and a screening strategy for control of thalassaemia to be designed in this area.

Adult↗
PubMed2003

Regeneration of bleaching clay waste by chemical activation with chloride salts.

Spent bleaching earth (SBE) was regenerated by chemical activation with low cost and low pollution chlorides as activating agents. Under the conditions of activation temperature of 600d egrees C and holding time of 1 h investigated, results show that fresh bleaching earth and regenerated bleaching earth are type IV with hysteresis loops corresponding to type H3 from nitrogen adsorption-desorption isotherms, indicating slit-shaped mesoporous structure. It is also found that the effect of the regeneration treatment studied in the present work on the pore structures and chemical properties of the resulting solids is negligible compared to the fresh bleaching earth. On the other hand, the pore properties of these chemically activated solids are higher than those of the sample regenerated from heat regeneration, but only approximate 45% of surface area are reclaimed. It implies that the carbon residues could be retained within pores and/or clogs the entrance of pores, resulting in a decrease in pore properties.

Adsorption↗
PubMed2001

Cloning, sequencing, heterologous expression, purification, and characterization of adenosylcobalamin-dependent D-ornithine aminomutase from Clostridium sticklandii.

D-Ornithine aminomutase from Clostridium sticklandii catalyzes the reversible rearrangement of d-ornithine to (2R,4S)-2,4-diaminopentanoic acid. The two genes encoding d-ornithine aminomutase have been cloned, sequenced, and expressed in Escherichia coli. The oraS gene, which encodes a protein of 121 amino acid residues with M(r) 12,800, is situated upstream of the oraE gene, which encodes a protein of 753 amino acid residues with M(r) 82,900. The holoenzyme appears to comprise a alpha(2)beta(2)-heterotetramer. OraS shows no significant homology to other proteins in the Swiss-Prot data base. The deduced amino acid sequence of OraE includes a conserved base-off/histidine-on cobalamin-binding motif, DXHXXG. OraE was expressed in E. coli as inclusion bodies. Refolding experiments on OraE indicate that the interactions between OraS and OraE and the binding of either pyridoxal phosphate or adenosylcobalamin play important roles in refolding process. The K(m) values for d-ornithine, 5'-deoxyadenosylcobalamin (AdoCbl), and pyridoxal 5'-phosphate (PLP) are 44.5 +/- 2.8, 0.43 +/- 0.04, and 1.5 +/- 0.1 microm, respectively; the k(cat) is 6.3 +/- 0.1 s(-1). The reaction was absolutely dependent upon OraE, OraS, AdoCbl, PLP, and D-ornithine being present in the assay; no other cofactors were required. A red-shift in UV-visible absorption spectrum is observed when free adenosylcobinamide is bound by recombinant D-ornithine aminomutase and no significant change in spectrum when free adenosylcobinamide is bound by mutant OraE-H618G, demonstrating that the enzyme binds adenosylcobalamin in base-off/histidine-on mode.

Amino Acid Motifs↗
PubMed2001

[Study on the differentiation and apoptosis of HL-60 cell line induced by Puerarin].

OBJECTIVE: To investigate the differentiation of HL-60 cells induced by different doses of Purerarin(PR) comparing with all-trans retinoic acid(ATRA) and to see if PR can induce apoptosis of HL-60 cells. METHODS: Cell differentiation was analyzed by NBT reduction, the ratio of NBT/MTT and CD11b, apoptosis by morphology, DNA electrophoresis, and flow cytometry(FCM). RESULTS: 80 micrograms.ml-1, 160 micrograms.ml-1, 320 micrograms.ml-1 PR could induce differentiation of HL-60 cells, no significant difference was observed between the cells treated with 1 mumol.L-1 ATRA and 320 micrograms.ml-1 PR. Treated with 320 micrograms.ml-1, 640 micrograms.ml-1 PR, HL-60 cells exhibited a morphological characteristic of apoptosis and typical DNA ladder on gel electrophoresis. FCM analysis showed that PR could interfere with cell cycle in HL-60 cells, with a increased ratio of sub-G1 in HL-60 cells. CONCLUSION: PR exerts effect on differentiation and induces apoptosis in HL-60 cells.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Protein-coenzyme interactions in adenosylcobalamin-dependent glutamate mutase.

Glutamate mutase catalyses an unusual isomerization involving free-radical intermediates that are generated by homolysis of the cobalt-carbon bond of the coenzyme adenosylcobalamin (coenzyme B(12)). A variety of techniques have been used to examine the interaction between the protein and adenosylcobalamin, and between the protein and the products of coenzyme homolysis, cob(II)alamin and 5'-deoxyadenosine. These include equilibrium gel filtration, isothermal titration calorimetry, and resonance Raman, UV-visible and EPR spectroscopies. The thermodynamics of adenosylcobalamin binding to the protein have been examined and appear to be entirely entropy-driven, with DeltaS=109 J.mol(-1).K(-1). The cobalt-carbon bond stretching frequency is unchanged upon coenzyme binding to the protein, arguing against a ground-state destabilization of the cobalt-carbon bond of adenosylcobalamin by the protein. However, reconstitution of the enzyme with cob(II)alamin and 5'-deoxyadenosine, the two stable intermediates formed subsequent to homolysis, results in the blue-shifting of two of the bands comprising the UV-visible spectrum of the corrin ring. The most plausible interpretation of this result is that an interaction between the protein, 5'-deoxyadenosine and cob(II)alamin introduces a distortion into the ring corrin that perturbs its electronic properties.

Cobamides↗
PubMed2001

The correlation of depression and gastric dysrhythmia in functional dyspepsia.

Psychologic factors in functional dyspepsia have been discussed in many previous articles. However, the relationship between depression and functional dyspepsia is still obscure. We investigated the impact of depression on clinical symptoms and gastric dysrhythmia in functional dyspepsia. Thirty-nine patients with functional dyspepsia and 18 healthy subjects were included. Patients were investigated with clinical symptoms assessment, Zung's self-rating depression scale, and electrogastrography. Patients with functional dyspepsia were divided into two groups: 21 patients with depression and 18 patients without depression. The depressed patients had similar total gastrointestinal symptom severity scores compared with the nondepressed patients, but with higher total symptom frequency scores (p < 0.05). With regards to symptoms, the depressed patients had higher abdominal fullness severity and frequency scores and nausea frequency scores. The patients with functional dyspepsia had a lower percentage of normal slow wave in both the fasting and fed states and a higher percentage of bradygastria in the fasting state and tachygastria in the postprandial state (p < 0.05). There was no significant difference in the percentage of bradygastria or tachygastria between the depressed and nondepressed patients. There was no correlation between the specific type of electrogastrographic abnormality and the presence or absence of depression in functional dyspepsia patients.

Adult↗
PubMed2001

Localization of c-di-GMP-binding protein with the linear terminal complexes of Acetobacter xylinum.

Specific labeling of a single row of cellulose-synthesizing complexes (terminal complexes, TC subunits, TCs, or TC arrays) in Acetobacter xylinum by antibodies raised against a 93-kDa protein (the cyclic dignanylic acid-binding protein) has been demonstrated by using the sodium dodecyl sulfate (SDS)-freeze-fracture labeling (FRL) technique. The antibodies to the 93-kDa protein specifically recognized the TC subunits on the protoplasmic fracture (PF) face of the outer membrane in A. xylinum; however, nonlabeled TCs were also observed. Two types of TC subunits (particles or pits) are observed on the PF face of the outer membrane: (i) immunogold-labeled TCs showing a line of depressions (pits) with an indistinct particle array and (ii) nonlabeled TC subunits with a distinct single row of particle arrays. The evidence indicates that the labeling patterns differ with respect to the presence or absence of certain TC subunits remaining attached to the replica after SDS treatment. This suggests the presence of at least two TC components, one in the outer membrane and the other in the cytoplasmic membrane. If the TC component in the outer membrane is preferentially fractured and remains attached to the ectoplasmic fracture face (or outer leaflet) of the outer membrane, subsequent replica formation reveals a pit or depression with positive antibody labeling on the PF face of the outer membrane. If the TC component in the outer membrane remains with the PF face (or inner leaflet) of the outer membrane, the innermost TC component is removed during SDS treatment and labeling does not occur. SDS-FRL of TCs in A. xylinum has enabled us to provide the first topological molecular analysis of component proteins in a cellulose-synthesizing TC structure in a prokaryotic organism.

Bacterial Proteins↗
PubMed2001

[Augmenter of liver regeneration: a novel cytokine].

Augmenter of liver regeneration (ALR) is a novel cytokine which specifically stimulates hepatic cell proliferation and is able to rescue acute liver failure caused by carbon tetrachloride. This article reviews the discovery, tissue distribution, functions and prospect of ALR and its relationship with hepatic stimulatory substance (HSS).

Animals↗
PubMed2000

Purification and properties of ornithine racemase from Clostridium sticklandii.

Ornithine racemase has been purified to homogeneity from Clostridium sticklandii, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This is the first racemase known to be highly specific to ornithine. This PLP-dependent enzyme has an M(r) of 92, 000, with a K(m) for L-ornithine of 0.77 +/- 0.05 mM and a k(cat) of 980 +/- 20 s(-1).

Amino Acid Isomerases↗
PubMed2000

Prolonged morphine treatment relieves thermal hyperalgesia in rats with sciatic nerve constriction injury.

We examined the effects of chronic morphine treatment with regular intermittent administration in a modified chronic constriction injury (CCI) model of the rat sciatic nerve originally introduced by Bennett and Xie. A painful neuropathy was induced over the left hind limb with sciatic nerve ligation, and sham surgery was done on the opposite side in male Sprague-Dawley rats. Paw-with-drawal latency (PWL) was obtained one day before surgery (pre-op baseline) and on the fourth day after surgery (post-op) to assure the development of thermal hyperalgesia. Morphine hydrochloride (5, 10, 15, and 20 mg/kg per day) was subcutaneously administered for 7 days to four experimental groups. The control group received normal saline rather than morphine under the same injection protocol. PWLs were evaluated on days 5, 7, 9, and 11 of the treatment. PWL decreased to 50-60% of the pre-op baseline or sham limb on the fourth day after surgery. Morphine's ability to reverse PWL appeared dose-related, and no tolerance developed during treatment with chronic intermittent administration. This may indicate that prolonged use of intermittently-administered morphine can be a feasible regimen for relief of neuropathic pain.

Animals↗
PubMed2000

Home-based patient-controlled epidural analgesia with bupivacaine for patients with intractable herpetic neuralgia.

This clinical report is based on retrospective observation of the outcome and effects of patient-controlled epidural analgesia (PCEA) with bupivacaine infusion administered at home to five patients with intractable herpetic neuralgia. All patients had severe pain (9 or 10 visual analogue scale [VAS]points) confined to the affected dermatomes, which was refractory to medication. The interval between zoster onset and PCEA application ranged from 27 to 60 days (mean, 37.2 d). The average daily amount of bupivacaine used was 36.5 to 91.2 mg (mean +/- standard deviation, 62.4 +/- 19.7 mg). The duration of PCEA therapy ranged from 10 to 28 days (18.4 +/- 7.6 d). One patient developed drug tolerance. All treatments resulted in effective and satisfactory pain relief (VAS, 0-3), with increase in physical activities to normal levels and easing of sleep and appetite impairment. No deleterious effects were found during PCEA therapy. After discontinuation of PCEA, two patients did not complain of pain but still had slight paresthesia, one of them required low-dose antidepressant for 17 days; three patients continued to have occasional sharp pain (VAS, 2-3) and required low-dose antidepressant and analgesic as-needed for one to six months. These results suggest that PCEA with bupivacaine infusion provides effective pain relief in patients with intractable herpetic neuralgia and is a feasible and effective home treatment modality with limited side effects.

Adult↗