Biomedical subjects
Publications and source records attributed to J Xia.
An effective synthesis is described for the preparation of all four mono trans isomers of arachidonic acid via deoxidation of epoxide precursors with lithium diphenylphosphide and quaternization with methyl iodide.
A complexation study on the new Zn(II) complexes of asymmetric tripodal ligand 2-[bis(2-aminoethyl)amino]ethanol (L) has revealed that the alcoholic OH group of complex ZnL exhibits remarkable acidity with a very low pK(a) value of 7.7 at 25 degrees C. Both the monomeric complex [ZnH(-0.25)L(H(2)O)](ClO(4))(1.75) (I) and the dimeric alkoxide-coordinating complex [Zn(2)(H(-1)L)(2)](ClO(4))(2) (II) were synthesized, and their structures were determined by X-ray diffraction. The Zn(II)-bound alkoxide, as the reactive nucleophile toward the hydrolysis of esters, has shown a second-order rate constant of 0.13 +/- 0.01 M(-1) s(-1) in 10% (v/v) CH(3)CN at 25 degrees C in 4-nitrophenyl acetate (NA) hydrolysis, which is almost the same as the corresponding value for the very reactive alcohol-dependent [12]aneN(3)-Zn complex. Present work shows for the first time that Zn(II) complexes of the asymmetric tripodal polyamine bearing an ethoxyl pod can also serve as good models of Zn(II)-containing enzymes.
OBJECTIVE: To establish the gene diagnosis of chavcot-Marie-Tooth disease (CMT) by (PCR) polymerase chain reaction and to study the molecular genetic characteristics of the Chinese CMT. METHODS: Mutation analysis of the Cx32, MPZ and PMP22 genes were performed by PCR-RFLP, PCR-SSCP, PCR-DGGE and/or direct sequencing in 32 CMT probands of the Hans in China. RESULTS: 21.9% of the CMT pedigrees had mutations in the Cx32, MPZ and PMP22 genes. Ten kinds of abnormal bands were found by PCR-SSCP, including 5 kinds of polymorphism and 5 point mutations in the exons of the gene (4 of the Cx32 and 1 of the MPZ). No point mutation of the PMP22 gene was found in these patients but two families (6.3%) were diagnosed as CMT1A by the PCR-RFLP, with the tandem repeat mutation of 1.5 Mb including the PMP22 gene. CONCLUSION: PCR-SSCP and PCR-RFLP are the first two screening methods in the gene diagnosis of CMT. PCR-DGGE is not appropriate for mutation analysis of Cx32. The point mutations must be certificated by sequencing. The mutation screening in the possible X-linkage family has to start with Cx32 gene.
Total syntheses of the GlyCAM-1 (glycosylation-dependent cell adhesion molecule-1) oligosaccharide structures: [alpha-NeuAc-(2 --> 3)-beta-Gal-(1 --> 4)-[alpha-Fuc-(1 --> 3)]-beta-(6-O-SO3Na)-GlcNAc-(1 --> 6)]-[alpha-NeuAc-(2 --> 3)-beta-Gal-(1 --> 3)]-alpha-GalNAc-OMe (1) and [alpha-NeuAc-(2 --> 3)-beta-Gal-(1 --> 4)-[alpha-Fuc-(1 --> 3)]-beta-GlcNAc-(1 --> 6)]-[alpha-NeuAc-(2 3)-beta-Gal-(1 --> 3)]-alpha-GalNAc-OMe (2) through a novel sialyl LewisX tetrasaccharide donor are described. Employing sequential glycosylation strategy, the starting trisaccharide was regio- and stereoselectively constructed through coupling of a disaccharide imidate with the monosaccharide acceptor phenyl-6-O-naphthylmethyl-2-deoxy-2-phthalimido-1-thio-beta-D-glucopyranoside with TMSOTf as a catalyst without affecting the SPh group. The novel sialyl Lewisx tetrasaccharide donor 3 was then obtained by alpha-L-fucosylation of trisaccharide acceptor with the 2,3,4-tri-O-benzyl-1-thio-beta-L-fucoside donor. The structure of the novel sialyl Lewisx tetrasaccharide was established by a combination of 2D DQF-COSY and 2D ROESY experiments. Target oligosaccharides 1 and 2 were eventually constructed through heptasaccharide which was obtained by regioselective assembly of advanced sialyl Lewisx tetrasaccharide donor 3 and a sialylated trisaccharide acceptor in a predictable and controlled manner. Finally, target heptasaccharides 1 and 2 were fully characterized by 2D DQF-COSY, 2D ROESY, HSQC, HMBC experiments and FAB mass spectroscopy.
BACKGROUND: Low-grade endometrial stromal sarcoma is generally an indolent tumor rich in estrogen and progesterone receptors. Objective responses to hormonal therapy, most commonly with megestrol acetate, have been reported. CASE: The patient is a 51-year-old woman who presented with low-grade endometrial stromal sarcoma confined to the uterus in 1991 and was treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy. Approximately 5 years later, the patient had recurrent pelvic disease treated with radiation therapy, followed by an attempt at resection. She was treated with megestrol acetate during the period she received radiation therapy with poor tolerance. Tamoxifen was then given with no tumor response. Megestrol acetate was restarted with progression of disease in the pelvis and abdomen. Letrozole was then given at a daily dose of 2.5 mg with partial response for a duration of 9 months. CONCLUSION: Letrozole at a daily dose of 2.5 mg may be effective in low-grade endometrial stromal sarcoma with positive estrogen receptors.
Due to the pressures of increasing population and developing economy all over the world, the present situation of water-quality management is far from satisfactory. To enhance sustainability of water-quality-management systems, in-depth research of the related barriers and the relevant mitigation approaches is desired. In this paper, recent developments, advancements, challenges, and barriers associated with practices of water-quality management were analyzed. A number of related methodologies, applications, and policy considerations were examined. Issues of information support, technology development, system integration, and policy implementation were discussed. Perspectives of sustainable water-quality management in the twenty-first century were investigated, demonstrating many demanding areas for enhanced research efforts, including issues of data availability and reliability, concerns in system complexity and methodology validity, limitations of computer techniques, usefulness of research outputs, difficulties in policy implementation, and necessity of training programs.
To explore the possibility to employ 99mTc-MIBI to monitor biological response of tumor cells after irradiation and to observe the relation between the radiation doses and the uptake levels of 99mTc-MIBI in tumor cells, the cells were irradiated with a single dose of 2 Gy, 10 Gy and 20 Gy respectively. The uptake of 99mTc-MIBI in each dosage group was determined before and 24, 48, 72 h after irradiation respectively. Apoptosis index (AI), plating efficiency (PE) of tumor cells was simultaneously determined. There was a positive correlation between uptake levels of 99mTc-MIBI and AI(r = -0.91, P < 0.05). A negative correlation was noted between the uptake levels and PE (r = -0.86, P < 0.05). It is suggested that 99mTc-MIBI may be used as a tracer to monitor the change of viability state of tumor cells after being irradiated with different doses.
Elucidation of the genetic basis of complex traits and diseases in humans includes the use of genome-wide association studies that depend on the analysis of a large number of diallelic markers. We describe the application of the amplified fragment length polymorphism (AFLP) technique as an efficient approach for rapidly identifying and scoring multiple variants in the human genome. Using a commercially available kit, we found that AFLP yields reproducible DNA fingerprints consisting of 42-132 fragments, 8% of which show variability between individuals. These variant markers appear to be from different chromosomes, and the majority of them is diallelic. Based on the information obtained in this study, it is possible to approximate the minimum number of selective AFLP primer combinations needed to approach a desired coverage density of all chromosomes. To our knowledge, this is the first study showing the general applicability of AFLP in humans and providing a constructive guide for the design of genomic studies in Homo sapiens with this robust methodology.
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Human lung tumor alpha1,3/4-L-fucosyltransferase (FT) was purified (2000-fold, 29% recovery) from 290 g of tissue by including a chromatography step on Affinity Gel-GDP. Two molecular forms (FTA, larger size carrying 15% alpha1,4-FT activity; FTB, the major form with 85% activity) were separated by further fractionation on a Sephacryl S-100 HR column. A difference in the electrophoretic mobilities of these two activities was also found on native polyacrylamide gel electrophoresis (PAGE). Both forms were devoid of typical alpha1,2-fucosylating activity but were associated with the novel alpha1,2-fucosylating ability of converting the Lewis a determinant to Lewis b. Based on percentage activity toward 2-O-MeGalbeta1,3GlcNAcbeta-O-Bn, both forms exhibited the same extent of activity toward various acceptors, which included sulfated, sialylated, or methylated LacNAc type 1 or type 2 as well as mucin core 2 acceptors. However, FTA and FTB exhibited a difference in their ability to act on mucin core 2 3'-sialyl LacNAc (activities 24.2% and 40.8%, respectively, as compared to 2-O-MeGalbeta1,3GlcNAcbeta-O-Bn). The unsubstituted LacNAc type 1 acceptors were 15-20 times as active as the corresponding LacNAc type 2 acceptors. The 3-O-substitution on the beta1,4-linked Gal (methyl, sulfate, or sialyl) in mucin core 2 acceptors increased the efficiency of these acceptors five- to eightfold. The most efficient acceptor for FTA and FTB was 3-O-sulfoGalbeta1,3GlcNAcbeta-O-Al (K(m) 100 and 47 microM, respectively). The K(m) (mM) values for 2-O-methyl Galbeta1,3GlcNAcbeta-O-Bn and 3-O-sialyl Galbeta1,3GlcNAcbeta-O-Bn were 0.40 and 2.5 (FTA) and 0.16 and 0.67 (FTB), respectively. The 35-kDa glycoprotein ancrod (from Malayan pit viper venom) containing 36% complex N-glycans with the antennae NeuAcalpha2,3Galbeta1,3GlcNAcbeta- acted as the best macromolecular acceptor substrate (K(m): 45 microM), as examined with FTB. On desialylation the acceptor efficiency dropped to approximately 50% (K(m) for asialo ancrod: 167 microM). Sialylglycoproteins, such as carcinoembryonic antigen, fetuin, and bovine alpha(1)-acid glycoprotein, were better acceptors than asialo fetuin. On the contrary, fetuin triantennary glycopeptide containing predominantly NeuAcalpha2,3Galbeta1,4GlcNAcbeta- was only 55% active as compared to the asialo glycopeptide (K(m): 1.43 and 0.63 mM, respectively). Thus, the human lung tumor alpha1,3/4-L-FT has the potential to generate clustered sialyl Lewis a and Lewis b determinants in N-glycans and sialyl Lewis x determinant in mucin core 2 structures.
A de novo complex chromosomal rearrangement (CCR) involving chromosomes 7, 8 and 9 in a male carrier was ascertained through his healthy wife's recurrent spontaneous abortions. Six pregnancies over eight years resulted in four spontaneous abortions and two livebirths who died perinatally due to abnormal vital signs. Cytogenetic analyses utilizing high resolution chromosome banding technique showed a deletion of band in a der(7) chromosome and an extra band inserting at 8q21.2. Another extra band was also observed at the band 9p24, but it could not be karyotypically determined. Fluorescent in-situ hybridization using chromosome 7 and 8 specific microdissected library as probes confirmed the insertion of a segment from the translocated chromosome 7 into a chromosome 8, and additionally revealed a translocation between chromosomes 7 and 9. The karyotype of the CCR carrier was determined as 46,XY,t(7;9)(q22;p24),ins(8;7)(q21.2;q22q32).ish der(9)(wcp7+);ins(8;7)(wcp8+,wcp7+). Comparing with previously reported male CCR carriers with our case, we conclude that male CCR carriers may not always present with infertility or subfertility phenotypes. This may suggest that rare transmission of male carriers could result from abnormal chromosomal rearrangements during meiosis and gametogenesis in addition to frequent infertility.
The title molecule, [Ni(C6H17N3O)2](ClO4)2, possesses a crystallographic centre of symmetry at the Ni(II) position. The coordination geometry around the Ni(II) atom is distorted octahedral, consisting of six N atoms from two tripodal polyamine ligands, while the ethanol O atoms of the ligands remain uncoordinated. The crystal packing shows two-dimensional layers and an infinite three-dimensional framework which is stabilized by a hydrogen-bonded network.
Complex maxillofacial malformations continue to present challenges in analysis and correction beyond modern technology. The purpose of this paper is to present a virtual-reality workbench for surgeons to perform virtual orthognathic surgical planning and soft-tissue prediction in three dimensions. A resulting surgical planning system, i.e., three-dimensional virtual-reality surgical-planning and soft-tissue prediction for orthognathic surgery, consists of four major stages: computed tomography (CT) data post-processing and reconstruction, three-dimensional (3-D) color facial soft-tissue model generation, virtual surgical planning and simulation, soft-tissue-change preoperative prediction. The surgical planning and simulation are based on a 3-D CT reconstructed bone model, whereas the soft-tissue prediction is based on color texture-mapped and individualized facial soft-tissue model. Our approach is able to provide a quantitative osteotomy-simulated bone model and prediction of postoperative appearance with photorealistic quality. The prediction appearance can be visualized from any arbitrary viewing point using a low-cost personal-computer-based system. This cost-effective solution can be easily adopted in any hospital for daily use.
OBJECTIVE: To identify the mutation characteristic of STK(11) gene in Chinese with Peutz-Jeghers syndrome(PJS) and establish the base of the gene diagnosis of PJS. METHODS: STK(11) germline mutation was analysed by DNA sequencing in 18 unrelation patients with PJS. RESULTS: Six novel mutations of STK (11) gene were detected in six unrelation patients. These mutations will lead to production of truncated protein. CONCLUSION: STK (11) gene mutation accounts for one third of the Chinese with PJS. The content of mutation includes single base substitution or deletion and one or two bases insertion. The mutations were widely found in different regions of the whole coding sequence, and 2/3 of those concentr ate in exon 1. Mutation frequency is 66.7% in the family suffering PJS in two or more generations, and 16.7% in the disseminated cases.
This paper presents an ultrasonic blood densitometer for dynamic measuring blood density. Compared with traditional blood densitometer, the ultrasonic blood densitometer has the advantages of high precision, fast response and little sample etc.
We developed a simple and effective method for collecting a large quantity of buccal cell DNA in school-based studies of seventh-grade and older children. Seventh-grade students at schools in Wuhan, China brushed each buccal surface with a soft toothbrush and then rinsed with 10 ml of water. We added 5 ml of 99% ethanol to preserve the sample. Among 1563 samples transported at room temperature over 1 week and then stored for 13-14 months at -70 degrees C before extraction, using a modified Gentra Puregene protocol, the median total DNA yield was 108 microg, range of 14 to 416 microg. We assayed every 20th sample (n = 77) for NAT2 by the PCR, and all samples gave a 1093-bp product. From the 1563 samples, we obtained a result for single nucleotide polymorphisms in the interleukin-13 gene (at +2044) by RFLP-PCR on 98.8% and in the promoter of the myeloperoxidase gene (at -463) by real-time PCR on 99.7%. A water-rinse method, that we used among 12th-grade students in Southern California, gave a lower total DNA yield than the toothbrush rinse (median of 17 microg) and a slightly reduced ability to generate a PCR product. However, 26 of 27 water-rinse samples gave a result for two genes, albumin and CYP1A1, using real-time PCR methods. We did not quantify human, versus bacterial, DNA in our samples. However, given the amounts of total DNA required for genotyping, a sample with the median yield of 108 microg should suffice for approximately 2160 genotypes by RFLP-PCR methods or five times as many by real-time PCR. We recommend the toothbrush-rinse method, combined with a modified Gentra Puregene DNA extraction protocol, for large-scale, in-person collections of buccal cell DNA in children. The method requires only inexpensive, readily available materials and produces a large quantity of high-quality DNA for PCR analyses.
OBJECTIVE: To observe the expression and changes of local cytokines network in rat heart transplantation so as to determine the role of cytokines in acute rejection of rat heart transplantation. METHODS: The Wistar rats (receptor) were divided into four groups: group A(control, n = 12), group B(IL-2 Mab treated, n = 12), group C [Cyclosporine A (CsA) treated, n = 12] and group D(IL-2Mab + CsA treated, n = 12). Hearts from SD rats were transplanted into a cervical location in Wistar. The local expression of IL-1 beta, IL-2, CD25, IL-4, IL-5, IL-6, IL-10, TNF alpha, IFN gamma was examined at 1, 3, 5, 7, 9, 11, 14 days after operation by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Allografts survival time was (8.3 +/- 1.7) days in group A, (29.2 +/- 7.1) days in group B, (26.4 +/- 5.7) days in group C, (55.0 +/- 10.6) days in group D. The expression of IL-1 beta, IL-4, IL-10, IFN gamma was up-regulated, and the expression of IL-2, CD25, IL-5, IL-6, TNF alpha was significantly inhibited in group A. The expression of IL-1 beta, IL-5, IL-6, IL-10, IFN gamma was up-regulated, and the expression of IL-2, IL-4, TNF alpha was significantly down-regulated in group B. The expression of IL-1 beta, IL-2, CD25, IL-5, TNF alpha, IFN gamma was up-regulated, and the expression of IL-4, IL-6, Il-10 was significantly down-regulated in group C. The expression of IL-4, IL-5, IL-6, IL-10 was up-regulated, and the expression of IL-1 beta, IL-2, CD25, IFN gamma, TNF alpha was significantly down-regulated in group D. CONCLUSIONS: Cytokines play an important role in the development of acute transplantational rejection. Different cytokines play different roles in different local environments; the main principle possibly is immune deviation.
OBJECTIVE: To investigate the effect of lactate-buffered peritoneal dialysis fluid (L-PDF) on human peritoneal mesothelial cells (HPMC) function. METHODS: Mesothelial cells from human omentum were isolated and cultured in vitro. Proliferation of HPMC was detected by MTT assay. The quantity of interleukin-8 (IL-8) and fibronectin (FN) in culture supernatants was determined by ELISA. Reverse transcription and polymerase chain reaction amplification were used to detect the expression of IL-8 mRNA in HPMC. Total cellular protein in these supernatants was estimated by using Lowry method. RESULTS: L-PDF inhibited proliferation of HPMC in a time-dependent manner. The levels of IL-8 and FN in the supernatants were remarkably high, and expression of IL-8 mRNA was up-regulated in HPMC exposure to L-PDF. During a subsequent recovery period of 48 hours in culture medium containing lipopolysaccharide (LPS, 10 mg/L), enterotoxin of staphylococcus aureus (10 mg/L) or TNFalpha(10 x 10(6) U/L), the levels of FN in the supernatants increased (P < 0.05). The levels of IL-8 also increased in HPMC stimulated with TNFalpha(P < 0.01). CONCLUSION: L-PDF inhibited proliferation of HPMC and increased levels of IL-8 and FN in the HPMC.