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Biomedical subjects

F Zhao

Publications and source records attributed to F Zhao.

At least 73 records · Page 4Linked to original sources

[Fluorescence studies on the mixed solid complexes of europium and terbium].

Complexes Eu2L3L' and Tb2L3L' (L = 0-phthalate, L' = 2,2'-dipyridyl) have been synthesized. Mixed the both complexes as different molar ratio, mechanically ground them, then obtained a series mixed solid complexes of europium and terbium. Their fluoresence and infrared spectra were investigated. The results showed that there were obviously change for their fluorescence intensities and peak positions as compared with Eu2L3L' or Tb2L3L'. The fluorescence intensities of europium ions were sensitized by terbium ions and those of terbium ions were quenched by europium ions. FTIR spectra indicated that there were a combined force between the two complexes in the mixed solid complexes.

Chelating Agents↗

[The identification of recombinant HIV-1 strains in IDUs in southwest and northwest China].

OBJECTIVE: To search for possible recombination of HIV-1 strains in China. METHODS: The blood samples were collected from the HIV infected individuals in areas where epidemic of more than two subtypes of HIV-1 were found. The HIV env and tat genes were amplified by nested PCR from PBMCs and directly sequenced and analyzed. RESULTS: The sequence analysis were performed on 14 HIV-1 strains collected in the subtype B' and C epidemic areas of China. No evidence of recombination after sequencing of env was found. The recombnant HIV-1 strains of subtype B' and C were found in 10 of the 14 samples tested when the first exon of the tat gene was sequenced. In addition, three subtype B' and one subtype C non-recombinant HIV-1 strains were found among IDUs in Sichuan Province. CONCLUSIONS: The recombinant HIV-1 strains of subtype B' and C were firstly identified in Sichuan Province of southwest China and Xinjiang Autonomous Region of western China. Their identical sequences and recombinant patterns indicated the same origin of the recombinant strains, it strongly indicates a close correlation between these two HIV epidemic regions. Since no other subtype of HIV-1 except the recombinant was found in Xinjiang, whereas both subtype B and C as well as B'/C recombinant were found in Sichuan, the recombination was most probably happened in Sichuan Province rather than in Xinjiang.

Amino Acid Sequence↗

[Preheating decrease the sensitivity of K562 cell to chemotherapeutic drugs].

Hyperthermia is a powerful tool for enhancing the effect of many chemical drugs on killing cells, but too many times of hyperthermia could decrease the effect and increase the ability of tumor cell against chemical drugs. Heat stress protein 70(HSP70) mRNA of K562 cell was analyzed by RT-PCR, and the chemosensitivity of K562 cell was tested by MTT method before and after heat-exposure. The results showed that HSP70 mRNA increased greatly after K562 cells exposed to 40 degrees C for 30 min and then it went to the top after 120 min heat-exposure. The sensitivity of K562 cell to adriamycin (ADM) and cyclophosphamide (CTX) in a usual dosage (1/250 of one dosage in clinical use) was in middle degree before exposed to heat, and the sensitivity dramatically went down after K562 cell being heat-stressed. The sensitivity of heat-stressed tumor cells to chemotherapeutic drugs was decreased, which may come from the increased expression of stress proteins in cells.

Antineoplastic Agents↗

Characterization of a swine chromosome-specific centromeric higher-order repeat.

The centromeric region of swine chromosomes is comprised of tandemly repeated, divergent DNA monomer units. Here we report that these divergent DNA monomer sequences are organized into higher-order repeats, analogous to the hierarchical organization of alpha-satellite monomers in human centromeres. In this study, a centromeric cosmid clone was shown to be comprised entirely of a 3.3-kb higher-order repeat, with independent copies of this higher-order repeat more than 99% identical to each other. This higher-order repeat is composed of ten divergent monomer units of approximately 340 bp. The ten monomers are on average 79% identical, and all ten monomers are arranged in the same 5' to 3' orientation. In FISH analysis, a cloned 3.3-kb higher-order repeat hybridized to the centromere of Chromosome (Chr) 9 in metaphase spreads and detected two discrete foci in interphase nuclei, demonstrating that this swine higher-order repeat is chromosome-specific. The Chr 9 centromeric array spanned approximately 2.2 Mb as determined by pulsed-field gel electrophoresis. Moreover, the swine Chr 9 centromere is highly polymorphic, because an EcoRI restriction site polymorphism was detected. Thus, the assembly of divergent satellite sequences into chromosome-specific higher-order repeats appears to be a common organizational feature of both the human and swine centromere and suggests that the evolutionary mechanism(s) that create and maintain higher-order repeats is conserved between their genomes.

Animals↗

The seismocardiogram as magnetic-field-compatible alternative to the electrocardiogram for cardiac stress monitoring.

Seismocardiography (SCG) is a methodology derived from the field of seismology to measure non-invasively compression waves generated by myocardial motion. The use of SCG is proposed here as method to monitor cardiac function during stress testing and magnetic resonance imaging (MRI). It is shown that recording of the seismocardiogram in subjects undergoing an MRI study is not compromised by flow-induced electrical voltages that can severely distort the electrocardiogram. Electromagnetic compatibility of the seismocardiograph device with the MRI scanner hardware was tested. Experiments in an animal model proved that changes in the SCG waveform during different levels of LAD stenosis correlate with the changes seen in LV function with cine MRI. The changes in the SCG waveform characteristic for the onset of ischemia were observed almost immediately after the creation of a flow-limiting stenosis. This novel application of SCG to monitor changes in peak acceleration from cardiac blood flow and wall motion may represent a solution to the long-standing and important problem of monitoring patients for signs of myocardial ischemia during MRI.

Coronary Circulation↗

Microsatellite markers from a microdissected swine chromosome 6 genomic library.

To develop additional microsatellite (MS) markers in the region of the porcine skeletal muscle ryanodine receptor gene (RYR1), a microdissected genomic library was generated from the proximal half of the q arm of swine chromosome 6. Purified DNA was restriction enzyme-digested, ligated to oligonucleotide adaptors and amplified by PCR using primers complementary to the adaptor sequences. The purity of the amplified products and boundaries of the microdissected chromosomal region were verified by fluorescence in situ hybridization. (CA)n-containing sequences were then identified in a small insert genomic library generated from the PCR-amplified microdissected DNA. Oligonucleotide primers were developed for the PCR amplification of 30 of the 46 (CA)n repeat-containing clones, which were subsequently used to amplify DNA isolated from unrelated pigs of different breeds to determine the informativeness of these MS markers. Twenty-two of these MS markers were genotyped on the University of Illinois Yorkshire x Meishan swine reference population. These 22 markers were all assigned within a 50.7-CM region of the swine chromosome 6 linkage map, indicating the specificity of the microdissected library.

Animals↗

Audioscan testing in patients with King-Kopetzky syndrome.

In this study, the Audioscan test has been used to detect early signs of hearing abnormalities in 80 patients with King-Kopetzky syndrome. A significantly higher prevalence of Audioscan notches between 500 and 3,000 Hz was found for each age band and gender in patients with King-Kopetzky syndrome than in control subjects. This indicates that Audioscan notches between 500 and 3,000 Hz may represent a fine hearing deficit as an indicator of mild auditory dysfunction in patients with King-Kopetzky syndrome. However, there was no significant difference in the percentage of notches in the 3,001-8,000 Hz frequency band between the King-Kopetzky syndrome and control groups.

Acoustic Stimulation↗

Test-retest variability of distortion-product otoacoustic emissions in human ears with normal hearing.

In the present study, the test-retest variability of distortion product otoacoustic emissions (DPOAEs) due to various causes has been assessed quantitatively at individual frequencies using the ILO88/92 system. The short-term variance was generally lower than 3 dB2. Changing the position and the fit of the probe may affect the level of background noise in the ear canal, which interferes with the responses of the DPOAEs mainly at low frequencies and can also influence the interaction of the resonances of the outer ear and acoustic stimuli. The long-term variance was significantly greater than short-term variance, but did not differ significantly from variance of refitting the probe. The total DPOAE variance was small across all the frequencies above 1000 Hz except for a small peak in the 2500 Hz range. This may be related to the low response amplitudes in this region. The limitation of DPOAE detection at frequencies below 1000 Hz must lead to caution in the interpretation of results in this frequency range. The magnitude of the total variance was similar to that found in audiometric studies.

Acoustic Stimulation↗

Consumption and production waste: another externality of tobacco use.

OBJECTIVE: To describe the waste produced by and environmental implications of individual cigarette consumption (filter tips, packages, and cartons) and tobacco manufacturing. STUDY SELECTION: All available articles and reports published since 1970 related to cigarette consumption and production waste were reviewed. DATA SOURCES: Global cigarette consumption data were used to estimate cigarette butt and packaging waste quantities. Data from the Center for Marine Conservation's International Coastal Cleanup Project were used to describe some environmental impacts of tobacco-related trash. Data from the United States Environmental Protection Agency's (EPA's) Toxics Release Inventory and reported global cigarette consumption totals were used to estimate waste production from cigarette manufacturing. DATA EXTRACTION AND SYNTHESIS: In 1995, an estimated 5.535 trillion cigarettes (27,675 million cartons and 276,753 million packages) were sold by the tobacco industry globally. Some of the wastes from these products were properly deposited, but a large amount of tobacco consumption waste ends up in the environment. Some is recovered during environmental clean-up days. For the past eight years (1990-1997), cigarette butts have been the leading item found during the International Coastal Cleanup Project; they accounted for 19.1% of all items collected in 1997. The tobacco manufacturing process produces liquid, solid, and airborne waste. Among those wastes, some materials, including nicotine, are designated by the EPA as Toxics Release Inventory (TRI) chemicals. These are possible environmental health hazards. In 1995, the global tobacco industry produced an estimated 2262 million kilograms of manufacturing waste and 209 million kilograms of chemical waste. In addition, total nicotine waste produced in the manufacture of reduced nicotine cigarettes was estimated at 300 million kilograms. CONCLUSIONS: Laws against littering relative to cigarette butts could be better enforced. Additional taxes might be levied on cigarette products that would then be directed to environmental clean-up efforts. The tobacco industry should improve the biodegradability of filters, reduce packaging waste, and educate its customers. Worksites and public buildings should be encouraged or required to supply appropriate disposal mechanisms at all building entrances. Public awareness campaigns about the magnitude and prevention of cigarette consumption waste could be developed through partnerships among environmental groups, health organisations, and environmental protection agencies. Tobacco production waste should be a source of concern and regulation by governments throughout the world; it contains numerous chemicals which may be considered health hazards, not the least of which is nicotine produced in the manufacture of low-nicotine cigarettes.

Environmental Monitoring↗

Homotypic and heterotypic interaction of the neurofibromatosis 2 tumor suppressor protein merlin and the ERM protein ezrin.

Ezrin, radixin and moesin (ERM) are homologous proteins, which are linkers between plasma membrane components and the actin-containing cytoskeleton. The ERM protein family members associate with each other in a homotypic and heterotypic manner. The neurofibromatosis 2 (NF2) tumor suppressor protein merlin (schwannomin) is structurally related to ERM members. Merlin is involved in tumorigenesis of NF2-associated and sporadic schwannomas and meningiomas, but the tumor suppressor mechanism is poorly understood. We have studied the ability of merlin to self-associate and bind ezrin. Ezrin was coimmunoprecipitated with merlin from lysates of human U251 glioma cells and from COS-1 cells transfected with cDNA encoding for merlin isoform I. The interaction was further studied and the association domains were mapped with the yeast two-hybrid system and with blot overlay and affinity precipitation experiments. The heterotypic binding of merlin and ezrin and the homotypic association of merlin involves interaction between the amino- and carboxy-termini. The amino-terminal association domain of merlin involves residues 1-339 and has similar features with the amino-terminal association domain of ezrin. The carboxy-terminal association domain cannot be mapped as precisely as in ezrin, but it requires residues 585-595 and a more amino-terminal segment. Unlike ezrin, merlin does not require activation for self-association but native merlin molecules can interact with each other. Heterodimerization between merlin and ezrin, however, occurs only following conformational alterations in both proteins. These results biochemically connect merlin to the cortical cytoskeleton and indicate differential regulation of merlin from ERM proteins.

Animals↗

[A case-control study on cerebral palsy in children].

OBJECTIVE: To identify the risk factors for cerebral palsy (CP) in children. METHODS: A population-based 1:2 matched case-control study was conducted during May to June 1997 in southern Jiangsu Province of China. RESULTS: Risk factors for CP in children could be summarized into four categories, i.e.; (1) fetal growth retardation, preterm delivery and low birth weight; (2) asphyxia at birth, intracranial hemorrhage, ischemic and hypoxic encephalopathy and hyperbilirubinemic encephalopathy; (3) delivery with vaccum suction and traumatic brain injury; and (4) other prenatal factors. CONCLUSION: The first and second categories of risk factors correlated strongly and reproducibly with CP in children. It is emphasized that antenatal care be enforced to prevent occurrence of risk factors, such as low birth weight, etc., and the newborns with asphyxia be vigorously rescued and put under close supervision. For risk factors in the third category, the key measures should be obstetric practice and health education for the parents. But, little about the knowledge of the risk factors in the fourth category has been understood, which could be associated with those in the first two categories.

Asphyxia Neonatorum↗

[6A8 cDNA encodes A type of alpha-mannosidase].

OBJECTIVE: To find the nature of the protein encoded by 6A8 cDNA. METHODS: In the light of that the ligand of Con A is mannoses and that the function of alpha-mannosidase is trimming of mannoses in the oligosaccharide chains of glycoproteins, COS-7 cells and CNE-2L2 cells, a cloned cell line of human nasopharyngeal carcinoma, were transfected with pRc/CMV-sense 6A8 cDNA or pRc/CMV-antisense 6A8 cDNA and the Con A binding to the cells was examined upon a lazer scan confocal microscope. RESULTS: The data demonstrated that with transfection of pRc/CMV-sense 6A8 cDNA the binding of Con A to the cells was decreased, but the staining of the cells with mAb 6A8 was enhanced, and vise versa for the cells with transfection of pRc/CMV-antisense 6A8 cDNA. CONCLUSIONS: The protein encoded by 6A8 cDNA might be a type of alpha-mannosidase recognized by mAb 6A8.

Animals↗

[Sequence analysis of human immunodeficiency virus type 1 tat gene among the long-term HIV infected non-progressoris in Yunnan province].

OBJECTIVE: HIV-1 tat gene is one of its regulatory genes necessary for its replication. This study is to explore whether the variation of tat gene influences the AIDS progress of HIV infected individual. METHODS: We carried out investigation on tat gene of HIV among the long term HIV infected non-progressors and the commonly infected individuals. Mononuclear cells of peripheral blood were isolated and cellular DNA was extracted. Nested PCR method was used to amplify tat gene and their sequences were analyzed. RESULTS: Blood were collected from 22 HIV infected individuals, of which 11 cases were infected with B subtype strains based on previous env gene analysis and belonged to long term non-progressors according to clinical features and immunology. The other 11 cases were common HIV infection of which 5 subtype B and 6 subtype C were found. Both long term non-progressor group (subtype B) and the commonly HIV infectedly group (subtype B) had constantly four amino acids different from that of international B subtype consensus sequence The both groups clustered randomly on the phylogenetic tree. In commonly HIV infected subtype C group there were 6 amino acids different from that of international subtype C. The variation inside the tatgene of common subtype C group was small. CONCLUSIONS: There was no regular variation and significant difference between long term HIV infected non-progressive group and commonly HIV infected subtype B group. There is no evidence showing that progressive speed of AIDS correlated with the tat sequence profile of HIV-1.

Amino Acid Sequence↗

[Spectrophotometric determination of cinnarizine based on charge-transfer reaction].

The charge-transfer (CT) complex formed between cinnarizine as the donor and 7, 7, 8, 8-Tetracyanoquinodimethane (TCNQ) as the acceptor in acetone-methanol has been studied by spectrophotometric method. Beer's law is obeyed in the range of 0-18 microg x mL(-1) of cinnarizine. The apparent molar absorptivity of CT complex at 743 nm is 1.58 x 10(4) L x mol(-1) x cm(-1). The composition of CT complex is found to be 1 : 1 by Bent-French and Job's methods. The relative standard deviation is less than 3% (n = 10). The method has been applied to the determination of cinnarizine in tablets with satisfactory results.

Calcium Channel Blockers↗

[Effects of glutamic acid on heat tolerance and 70 kD proteins of Drosophila melanogaster].

From supplement of dietary glutamic acid, the heat tolerance ability of Drosophila and the change of Hsp70(heat shock proteins) were studied. The results showed that the supplement of dietary glutamic acid could increase the survival time and the contents Hsp70 of Drosophila, in the 37 degrees C heat environment; but could not get the Hsp70 rise up when Drosophila were in 25 degrees C. Based on the findings, we could make the conclusion that supplement dietary glutamic acid could benefit the heat tolerance ability of Drosophila, and it might be related to the increase of Hsp70.

Animals↗

[Effect of zinc on the cellular immunity and NK cell activity in acute heat exposed rats].

To study the effects of zinc on the cellular immunity and NK cell activity in acute heat-exposed rats. Rats were fed with dietary containing high, moderate and low zinc for 15 days. The concentrations of zinc in high, moderate and low zinc dietary are 92.20 mg/kg, 45.61 mg/kg and 21.70 mg/kg respectively. After exposed to acute heat (41.5 degrees C) for 5 min, 30 min and 60 min, the rats were killed and the cellular immunity and NK cell activity were measured. The proliferation of lymphocyte and the NK cell activity were higher in high zinc group than in moderate and low zinc groups no matter the rats were exposed to heat or not. Zinc can improve the cellular immunity and NK cell activity in acute heat exposed rats.

Animals↗