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Biomedical subjects

Z Chen

Publications and source records attributed to Z Chen.

At least 901 records · Page 50Linked to original sources
PubMed1998

[Nucleotide and protein sequence analysis of rice dwarf virus replicase(segment S1)].

The full length cDNA of Rice Dwarf Virus (RDV) Fujian isolate genome segment S1 was cloned and full length sequence was determined. The results showed that S1 is 4422 bp in length and contains a major open reading frame which encodes a polypeptide with 1444 amino acids. The major ORF contains the RNA-dependent RNA polymerase (RDRP) consensus sequences, such as motif I (DXXXXD) motif II (SGXXXTXXXN) and motif III(GDD). In addition to the three motifs, a well-conserved region (EXXKXY) is found following motif III. Therefore, we suggest that the protein encoded by S1 encodes the virus RDRP. Homology comparison of the nucleotide and amino acid sequences of the RDV Fujian isolate with the known sequences of the Japanese isolate showed that the both isolate have 95% and 97% on nucleotide and amino acid sequences, respectively.

Amino Acid Sequence↗
PubMed1998

[Morphological observation of the endogenous endophthalmitis of cryptococcus neoformans].

PURPOSE: To observe the pathologic change of the endogenous endophthalmitis of cryptococcus neoformans. METHODS: Light and electron microscope were used. RESULT: The choroid was focally tumor-like by an inflammatory cells infiltrate, which consisted of multinucleated gicant, epithelioid cells and lymphocytes. Special stains (Grocott's methnamine silver, PAS, alcian blue) and electron microscope disclosed the budding form of cryptococcus neoformans. CONCLUSION: The morphologic examinations are only an effectivel method of diagrosing the endogenous endophthalmitis of cryptococcus neoformans.

Adult↗
PubMed1998

Dacryology in China.

PURPOSE: International Society of Dacryology held the IV International Congress in Stockholm on June 1996. I was warmly invited as a guest of honor beforehand to deliver a lecture on a special topic of "Dacryology in China" there, so that the world might understand the dacryology in China, and thus the international growth of dacryology as a discipline would be promoted. METHODS: In China tear lab research and clinical research of LG are nearly empty except a few papers published. We had studied 3 items on LS for 28 years before 1979, and put our attention mainly on dacryology since 1979 by 3 stages: (1) collecting literatures (1979-81); (2) lab research (1981-84) and (3) clinical research, put DE as the key point by 4 steps: DE diagnosis (1984-86); DE treatment (1987-91); DE Condition Judgement (1989-92) & DE cause & mechanism (1991-95). RESULTS: In the past 44 years, esp. from 1979 on, in a planned way, we have systematically researched the dacryology with main results below: created new word "Leiyexue" in Chinese & its English words, dacryology & lacrimology by adding-ology to dacrya & lacrima; made LS consisted of reflex LG & LP, and basic LG besides; found out the normal & abnormal data of tear and serum LF & its iron bindingcapacity; MDH, LDH & isoenzymes; beta 2 m; MDA & antioxidants; trace elements, prostaglandins, intramuscular gentamicin passing the blood-tear barrier; bacteria, fungi, anaerobe, virus & parasite; Ig, T cell & subsets, Langerhan cell, HLA antigen; in cidence (KCS, 0.3-3%, trancomatous DE 0.003%); the parallel correlations between DE graded by rb, BUT & Slt; and in SS, lymphocytes infiltration in LG; Lab G & conjunctiva; LF (< 100 mg%) & beta 2 m (> 1.7 mg%); and testosterone receptors in LG; negated presence of tear Beta-lysim; set up a series of models for researching & a complete set of measures to diagnose, grade, judge and treat DE, deviced new operations. AT & prescription for DE; proved SS being autoimmune & EB virus, its one cause. CONCLUSIONS: This relatively, overall & systematical research of dacryology already have been widely applied to practice with over 100 papers published. It indicates that LS & its disease as a scientific discipline under the term of dacryology to grow up is entirely possible and extremely needful.

Animals↗
PubMed1998

[AAS determination of trace lead, cadmium, copper and nickel by enrichment with 2-mercaptobenzimidazole chelating cellulose].

Chelating cellulose is of simple preparation,excellent nature and low cost. MBM chelating cellulose was prepared with good chelating reagent (2-mercaptobenzimidazole) grafted on cotton by indirect etherification method. Four heavy metal ions in one solution can be simultaneously preconcentrated and eluted under good condition. Results have shown that the approach for separating and preconcentrating trace of Cu, Pb, Cd and Ni has advantages of high exchanging speed, high preconcentration multiple, high selectivity, easy elution and excellent results.

Benzimidazoles↗
PubMed1998

Optical Doppler tomography: imaging in vivo blood flow dynamics following pharmacological intervention and photodynamic therapy.

A noninvasive optical technique has been developed for imaging in vivo blood flow dynamics and vessel structure with high spatial resolution. The technique is based on optical Doppler tomography, which combines Doppler velocimetry with optical coherence tomography to measure blood flow velocity at discrete spatial locations in turbid biological tissue. Applications of this technique for monitoring changes in blood flow dynamics and vessel structure following pharmacological intervention and photodynamic therapy are demonstrated.

Allantois↗
PubMed1998

Effects of feeding a liquid diet for one year to New Zealand White rabbits.

We compared the long-term effects of a newly designed liquid diet with a commercially available dry diet in New Zealand White rabbits. Body weight gain, feed consumption, and plasma lipid concentrations were measured periodically throughout the 1-year study. In addition, specific hepatic enzyme activities in serum were quantified to examine the effects of liquid diet on the liver over the 1-year feeding trial. At 52 weeks, body weight gains between the liquid- and dry-fed groups were similar. Regardless of sex, plasma phospholipid concentrations were higher in the control group than in the liquid-fed group. Plasma triglyceride concentrations were increased in liquid-fed female rabbits, compared with either male group or control-fed females. A somewhat similar effect was observed in plasma cholesterol concentration, which was higher in female rabbits regardless of diet type. After the 52-week trial, the rabbits had no clinical biochemical signs of liver damage. Results of this study indicate that a liquid diet can be fed to New Zealand White rabbits for a long period, and may provide an alternative route (food source) for future pathophysiologic studies.

Animals↗
PubMed1998

Brain capillary endothelial cells express MBEC1, a protein that is related to the Clostridium perfringens enterotoxin receptors.

Brain capillary endothelial cells compose the blood-brain barrier, which has a crucial role in maintaining the normal extracellular environment of the central nervous system. We have developed a method to isolate endothelial cells from mouse brain and maintain them in a relatively pure primary culture. Using a subtractive hybridization technique, a novel cDNA, termed MBEC1 (mouse brain endothelial cell 1), has been isolated from the cultured mouse brain capillary endothelial cells. MBEC1 is a 1435-bp cDNA predicted to encode a protein of 218 amino acids. The predicted protein is similar to those of the newly characterized Clostridium perfringens enterotoxin receptors and is the mouse homolog of a recently described human cDNA clone, which is hemizygously deleted in individuals with velo-cardio-facial syndrome and DiGeorge syndrome. MBEC1 was expressed in our cultured MBEC, in freshly isolated MBEC, in a variety of mouse organs, and in mouse embryos as early as embryonic Day 7. In situ hybridization and immunocytochemical analyses revealed the presence of the MBEC1 mRNA and its protein product in brain capillary endothelial cells, as well as in a subset of other endothelial and epithelial cells. Moreover, developmental regulation of expression of MBEC1 was present in respiratory epithelium. Our research thus provides a new molecule for further study of the function of normal and abnormal blood-brain barrier as well as of other specialized endothelia and epithelia.

Amino Acid Sequence↗
PubMed1998

[Latex allergy: local hypersensitivity reaction cause by an esophageal catheter in compliance determination].

We report on two latex-allergic subjects who developed local hypersensitivity reactions after their lung compliance was measured by an oesophagus balloon catheter. Protein and allergen analyses of this catheter showed values of 85 and 9.8 micrograms per gram rubber. It is concluded that latex-allergic subjects should not undergo examinations with latex allergen-containing catheters. To our knowledge, this is the first report on allergic reactions caused by latex balloons of an oesophagus catheter.

Adult↗
PubMed1998

Evidence for mitochondrial uptake of glutathione by dicarboxylate and 2-oxoglutarate carriers.

The role of organic anion transporters in the mitochondrial uptake of glutathione (GSH) was investigated by assessing competition with substrates or inhibition with inhibitors of specific carriers and modulation of mitochondrial energetics. Potential artifacts in the transport methodology, including contamination of matrix space with extramitochondrial fluid, changes in matrix volume during incubations, efflux of transported GSH during sample processing, induction of the membrane permeability transition, contamination of the mitochondrial preparation with plasma membranes and GSH degradation, were corrected or eliminated. Substrates (i.e., malate, succinate) and an inhibitor (i.e., butylmalonate) of the dicarboxylate carrier, an inhibitor (i.e., phenylsuccinate) of the 2-oxoglutarate carrier, and glutamate produced significant inhibition of GSH uptake whereas substrates and inhibitors of the mono- and tricarboxylate carriers were generally without effect. Phosphoenolpyruvate, which is a substrate for the tricarboxylate carrier, inhibited GSH uptake, but this was due to induction of the membrane permeability transition and not to competition for uptake. Although glutamate inhibited GSH uptake, the converse did not occur. GSH uptake was pH-independent and aspartate had no effect, which suggest that the glutamate and glutamate-aspartate carriers are not involved in GSH uptake but that the glutamyl residue of GSH may be important in its transport. GSH uptake was dependent on phosphate and ATP generation. Hence, we conclude that both the dicarboxylate and 2-oxoglutarate carriers of the inner membrane can catalyze uptake of GSH into the matrix. The function of an additional, novel transporter cannot be excluded at present. This is the first study to define the function of mitochondrial anion carriers in GSH transport.

Adenosine Triphosphate↗
PubMed1998

[Chinese Human Genome Project--opportunity and challenge].

The Chinese Human Genome Project(HGP) started in 1993 and has since made substantial progress in 3 major aspects: the genome resource conservation and genetic polymorphism studies of multiple Chinese nationalities; the development of an advanced technological system for genome research; the cloning of some desease-related genes and a large number of expressed sequence tags(ESTs). At the same time a qualified research team has been formed and some centers for genome studies have been founded in the country. The major tasks in the next phase of the project are: (1) Further expanding the genetic material conservation scope including collection of more DNA samples and establishment of more immortalized cell lines; (2) Developing morbid genomics which includes epidemiological survey and registration, collection, maintenance and banking of the data and genetic material resource; making significant progress in mapping, cloning, mutation screening, and large-scale sequencing of the genes related to tumors, inheritable diseases and particularly multigenic diseases in the hope that a number of genes for important diseases will be obtained; (3) Initiation of the functional genomics which includes studies on bioinformatics, expression spectrum of transcription and translation of the genome in physiological and pathological processes; (4) Enhancing the studies on the ethical, legal and social issues related to human genome sciences.

China↗
PubMed1998

[Studies on complex chromosomal translocation and their relevance to clinical prognosis in acute promyelocytic leukemia].

OBJECTIVE: To study the relationship between the complex chromosome translocation in acute promyelocytic leukemia(APL, M3) and clinical therapy and prognosis. METHODS: Chromosome translocation and PML-RAR fusion transcript in three APL patients were studied by using karyotypic analysis, fluorescence in situ hybridization and reverse transcriptase/polymerase chain reaction. RESULTS: The findings revealed that all these cases had PML/RAR A gene rearrangement. Apart from the chromosomes 15 and 17 involved in the translocation, other multiple chromosomes including 5, 11, 16, 22 were also implicated in complex translocations, which to some extent seemed to be related with clinical prognosis. CONCLUSION: This study provides additional information for monitoring clinical therapy and prognostic evaluation.

Adult↗
PubMed1998

Plasma endothelin 1 concentrations in children with congenital heart defects.

BACKGROUND: To investigate the changes in plasma endothelin-1 (ET-1) concentrations in patients with congenital heart defects. METHODS: Plasma ET-1 concentrations were measured by using radio-immunoassay in 50 patients in a prospective study. In 35 patients with ventricular septal defect, 20 cases had pulmonary hypertension (group 1) and 15 cases had normal pulmonary artery pressure (group 2). The other 15 patients with atrial septal defect had normal pulmonary artery pressure (group 3). Blood samples were obtained from pulmonary artery, aorta and radial artery. RESULTS: Plasma ET-1 concentration in group 1 was significantly higher than those in group 2 and group 3 at all sampling sites and all different times (p < 0.01), and plasma ET-1 concentration was slightly higher in group 3 than in group 2 (p > 0.05). Plasma ET-1 concentration at aorta were also significantly higher than that at pulmonary artery in group 1 (p < 0.01). In patients with ventricular septal detect, pulmonary blood flow had a linear positive correlation with plasma ET-1 concentration (r = 0.75, p < 0.01) and there was also a significant positive correlation between plasma ET-1 concentration and pulmonary artery pressure (r = 0.68, p < 0.05). After surgical repair of the defects, plasma ET-1 concentration decreased except for 6 cases with the pulmonary resistance more than 800 dyne.sec.cm-5. CONCLUSIONS: Plasma ET-1 concentrations are elevated in patients with congenital heart defect associated with left-to-right shunt and may have an important role in the pathogenesis of pulmonary hypertension.

Child↗
PubMed1998

The GOR47-1 sequence in human DNA encoding for a potential autoantigen in connection with hepatitis C--a sequence not only reserved for humans.

The sequence 'GOR47-1' is a consistent part of human DNA; the expressed polypeptide of it 'GOR' is accepted to be an autoantigen, and the anti-GOR an autoantibody. However, GOR47-1 was originally isolated through a cDNA clone from blood of a chimpanzee. This animal belonged to a series of chimpanzees, in which human plasma of a patient with non-A, non-B hepatitis had been passaged. To date, nothing is known how it is that this 'sequence GOR47-1' without recognizable self-replicating properties and allocated to the human genome could be isolated from a chimpanzee plasma. The aim of this study was to detect by polymerase chain reaction GOR47-1 sequences in healthy, anti-HCV-negative humans, HCV-positive patients, chimpanzee, snake, and in maize and tobacco plants. The GOR47-1 sequence is present not only in human DNA but also with a high degree of homology in chimpanzee DNA. Essential parts of this sequence are also present in DNA of a snake and the two plants listed above. Our findings reveal that the GOR47-1 sequence isolated from a chimpanzee was probably of the chimpanzee origin. This fact has not yet been considered up until now, when discussing the role of GOR/anti-GOR in humans particularly suffering from chronic hepatitis C.

Animals↗
PubMed1998

[Asthma and rhinoconjunctivitis caused by castor bean dust].

A 57 years old trader of agricultural goods with chronic asthma had attended our medical department for diagnosis and therapy. Since more than 35 years the patient had always experienced work-related asthma episode and rhinoconjunctivities when he worked in workplace where castor-bean oil cake as fertilizer was sold. With the intensive contact with castor-bean containing goods beginning about eight years ago, his asthma attack had become chronic. The allergological diagnosis confirmed that he had high-degree type I-allergy to castor-bean allergens.

Agricultural Workers' Diseases↗