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Biomedical subjects

J Yuan

Publications and source records attributed to J Yuan.

At least 235 records · Page 13Linked to original sources
PubMed1997

[Gene expression of basic fibroblast growth factor receptor in bovine lens epithelial cells].

OBJECTIVE: To characterize the mechanism of promotive effects of basic fibroblast growth factor (bFGF) on proliferation of lens epithelial cells. METHODS: RNA was extracted from cultured bovine lens epithelial cells of second passage and then cDNA was synthesized with reverse transcription. cDNA segments were amplified by polymerase chain reaction using bFGF receptor oligonucleotide primer from sequence of fibroblast cells in human placenta. Then, amplified cDNA segments were cloned and sequenced by Sanger method of dideoxy-chain termination. RESULTS: It was found that the bFGF receptor mRNA in bovine lens epithelial cells was detected and partial amino-acid sequences of bovine bFGF receptor are almost the same as that of human's except 3 amino-acids. CONCLUSIONS: bFGF receptor exists in lens epithelial cells, and when bFGF is bound to its receptor, the binding plays an important role in lens epithelial cell proliferation and capsular opacity after cataract surgery.

Amino Acid Sequence↗
PubMed1997

116 cases of coronary angina pectoris treated with powder composed of radix ginseng, radix notoginseng and succinum.

116 cases of coronary angina pectoris were treated with a powder composed of Radix Ginseng, Radix Notoginseng and Succinum, which was an empirical prescription of Dr. Yue Meizhong ([symbol: see text]), and compared with patients treated Fufang Danshen Tablet (a compound prescription of Radix Salviae Miltiorrhizae) as the control group. Results indicated that the curative effects and ECG in the treated group were better than that in the control group (P < 0.01), so were improvement of general symptoms, physical strength as well as changes of lipid metabolism and microcirculation of nail fold.

Adult↗
PubMed1997

[Clinical and image diagnostics of brain stem infarction].

Clinical features and image diagnostic characteristics of brain stem infarction were studied in 28 patients to facilitate early diagnosis. Crossed hemiparesis was found in all the patients with medulla oblongata and midbrain infarction. Pontine infarction had a variety of clinical syndromes as follows: (1) crossed-hemiparesis in 8 cases (44.4%) and ipsilateral hemiataxia in one case. (2) tetraplegia in 3 cases (16.7%). (3) pure hemiparesthesia in 4 cases. (4) hemiparesis and hemiparesthesia without cranial nerve palsy in 3 cases (16.7%). MRI was found to be a very useful diagnostic measure for brain stem infarction with a positive rate of 82.6%. However, brain stem infarction was sometimes not revealed by MRI. Brain stem infarction could not be diagnosed by CT, but brainstem hemorrhage might be excluded by CT.

Adult↗
PubMed1997

[Differential display analysis of human fetal brain mRNAs and isolation of brain-specific novel ESTs].

Using the differential display technique (DDRT-PCR) originally developed by Liang and Pardee, we tried to isolate the stage-specific or tissue-specific genes in the developing human neural system (brain). With about fifty sets of arbitrary primers and anchored primers, DDRT-PCR was carried out to analyze the differentially expressed mRNAs between human fetal brains of different developmental stage or different parts of human fetal brain at the same developmental stage. About one hundred bands containing cDNA fragments of differential interest were cut out from the polyacrylamide gel, thirty-four of which were cloned and sequenced. They were accepted as novel cDNA sequences by GeneBank. In order to check the feasibility of DDRT-PCR, three of the thirty-four cDNA sequences were randomly chosen as probes for further analysis by dot blot RNA hybridization, and two proved to be specifically expressed in human brain.

Brain Chemistry↗
PubMed1997

[Construction of poliovirus cDNA chimera with (NKNDD)n and (NANP)n].

Oligonucleotides encoding one copy of NKNDD, containing a P.f. B epitope NKND, and two copies of CSP repeated B epitope NANP were synthesized. After self-ligation, NKNDD and (NANP)2 were cloned into the intermediate vector pSKMM. Series of clones with different copies of NKNDD and NANP were identified. (NKNDD)n/MM with three, four, five, eight copies of NKNDD and (NANP)n/MM with four, six copies of NANP were chosen. Then (NKNDD)n and (NANP)n of these recombinants were recovered respectively and finally inserted into the N-Ag I site of poliovirus type I Mahoney strain full-length cDNA, which is contained in the expression plasmid pSV202H+. As using semi-quantitative hybridization in identifying tranformants, the procedure in our experiment for cloning different copies of NKNDD and NANP was greatly simplified.

Animals↗
PubMed1997

[Study of the relationship between human quality and reliability].

To clarify the relationship between human quality and reliability, 1925 experiments in 20 subjects were carried out to study the relationship between disposition character, digital memory, graphic memory, multi-reaction time and education level and simulated aircraft operation. Meanwhile, effects of task difficulty and enviromental factor on human reliability were also studied. The results showed that human quality can be predicted and evaluated through experimental methods. The better the human quality, the higher the human reliability.

Aviation↗
PubMed1997

[Detection of desmosine in elastin by high performance liquid chromatography (HPLC)].

An assay of desmosine (DES) in elastin hydrolysate was performed by HPLC. Desmosine alone or its mixture with tyrosine and phenylalanine as well as elastin hydrolysate was separated on a C18 column eluted with a mobile phase of MeOH:H2O (2:8, V/V) and detected at UV-280nm. The results showed that the time of DES eluted in all cases mentioned above was comparable. The ratio of peak area (CA) and peak height (CH) between DES and Tyr is 1.4% and 3.4% resectively. It could be as a reliable measure to evaluate the quantity of DES in elastin. The correlation coefficient r was 0.9956 in the range of 0.16-0.64mg/L for a calibration curve of DES concentration vs peak area. In conclusion, this method could be used as a biochemical indication to detect the degradation level of elastin in the pathological state.

Chromatography, High Pressure Liquid↗
PubMed1997

[Simultaneous determination of carotenoids and chlorophylls in algae by high performance liquid chromatography].

An isocratic reversed-phase HPLC method for the simultaneous determination of carotenoids and chlorophylls in algae is presented. Both carotenoids and chlorophylls were separated by using a C18 column and a mobile phase consisting of dichloromethane/acetonitrile/methanol/water (22.5:9.5:67.5:0.5). The flow rate was 1.0mL/min. These pigments were detected by a UV-VIS absorbance detector set at 450nm. The average recoveries of these pigments by standard addition method were 99.1% for lutein, 98.5% for alpha-carotene, 99.4% for beta-carotene, 100.6% for chlorophyll a and 99.9% for chlorophyll b. The relative standard deviations of these pigments were 2.4% for lutein, 5.6% for alpha-carotene, 6.0% for beta-carotene, 4.1% for chlorophyll a and 4.0% for chlorophyll b. The calibration curves for these pigments gave good linearity over a wide range of 0-50mg/L (r = 0.9992-0.9999). The retention times were 3.0 min for lutein, 4.7 min for chlorophyll b, 6.3 min for chlorophyll a, 14.1 min for alpha-carotene, and 14.7 min for beta-carotene. Using this method, carotenoids and chlorophylls were determined in Spirulina platensis, Chlorella vulgaris and Haematococcus lacustris. Chlorella vulgaris and Haematococcus lacustris samples were ground in a B. Braun homogenizer. Spirulina platensis sample was smashed by supersonic wave. Acetone was used as extractant.

Carotenoids↗
PubMed1997

[Photoluminescence and UV-Vis absorption spectra characteristics of metal complexes of 8-hydroxyquinoline].

8-hydroxyquinoline complexes of Na(I), Ca(II), Mg(II), Zn(II), Cu(II), Mn(II), Al(III), In(III) and La(III) were synthesized. Photoluminescence (PL) and UV-Vis absorption spectra characteristics of these complexes and 8-hydroxyquinoline are reported. Except complexes of Cu and Mn, most of these complexes reveal photoluminescence. With the polarization force of metal cations increasing, the PL peak shows red-shift and two broad absorption peak in UV-Vis (300-400nm) absorption spectra distinctly appears apart.

English Abstract↗
PubMed1997

Polo-like kinase, a novel marker for cellular proliferation.

PLK (polo-like kinase) belongs to a family of serine/threonine kinases and represents the human counterpart of polo in Drosophila melanogaster and of CDC5 in Saccharomyces cerevisiae. It is strongly involved in spindle formation and chromosome segregation during mitosis. We have shown previously that PLK mRNA expression correlates with the mitotic activity of cells and the prognosis of lung cancer patients. In this report, the level of PLK protein was analyzed using immunohistochemical techniques. PLK protein was found expressed in the nuclei of tumor cells from lung and breast cancer as well as in several tumor cell lines. Furthermore, in peripheral lymphocytes treated with phytohemagglutinin, elevated proliferative activity of the cells correlated with the up-regulation of PLK protein expression. In contrast, in U937 and HL-60 cells after induction of differentiation with phorbol ester, PLK immunostaining disappeared under conditions of terminal differentiation. Most of the PLK protein was found in the nucleus of proliferating cells with diffuse but distinct staining also in the cytoplasm. Taken together, high levels of PLK protein are associated with cellular proliferation. Combined with other proliferative and oncogene markers, PLK may be useful for improved prediction of the clinical prognosis of cancer patients and for early cancer diagnosis. Due to its activity late in the cell cycle, it may be a target for cancer chemotherapy.

Adenocarcinoma↗
PubMed1997

Selective serotonin reuptake inhibitors dissociate fenfluramine's anorectic and neurotoxic effects: importance of dose, species and drug.

Fenfluramine, a clinically prescribed appetite suppressant, has been found to damage brain serotonin (5-HT) neurons in every animal species tested to date. Recent findings indicate that fluoxetine, a selective 5-HT reuptake inhibitor (SSRI), can prevent fenfluramine-induced 5-HT neurotoxicity without blocking fenfluramine-induced appetite suppression. The purpose of our studies was several-fold: 1) To determine whether the ability for fluoxetine to dissociate fenfluramine-induced anorexia and neurotoxicity is dose-related; 2) to ascertain whether other SSRIs also prevent fenfluramine-induced neurotoxicity without altering its anorectic effect; 3) to determine whether similar fluoxetine/fenfluramine interactions are seen in another animal species (i.e., mice) and 4) to determine whether decreases in food intake seen after the fluoxetine/fenfluramine combination can be attributed to nonspecific behavioral suppression. Results from our studies indicate that fluoxetine's effects are, indeed, dose-related, because higher doses of fluoxetine are required to protect against the 5-HT neurotoxic effects of higher doses of fenfluramine. Further, our results indicate that fluoxetine's effects generalize to all other SSRIs tested (citalopram, paroxetine and sertraline), as well as to other species (mice). Finally, our results demonstrate that anorexia in animals receiving the fenfluramine/fluoxetine combination is not secondary to nonspecific behavioral suppression, because water intake is increased although food intake is decreased in the same animals. Together, these data suggest that the anorectic and 5-HT neurotoxic effects of fenfluramine may involve different mechanisms, and that by combining fenfluramine with SSRIs, it may be possible to exploit fenfluramine's clinically useful properties (e.g., anorexia) without risking brain 5-HT neural injury.

Animals↗
PubMed1997

Creative inservices to meet mandatory education requirements.

To meet the mandates of federal and accreditation bodies, home care organizations must be prepared to conduct required education. There is a need to be creative and heighten the interest of the staff while doing more with shrinking education dollars. This article presents one agency's approach to the annual mandatory inservice program that allows the staff to have fun while learning.

Community Health Nursing↗
PubMed1997

Predictions of mathematical models of tissue oxygenation and generation of singlet oxygen during photodynamic therapy.

Photodynamic therapy (PDT) is a relatively new protocol for cancer treatment which has recently been approved for limited clinical use. Traditionally, the success of treatment with PDT has been compared on the basis of total light delivery. Using the mathematical model of Henning et al. (Radiat. Res. 142, 221-226, 1995), we have determined that when oxygen is not depleted from the tissue, the concentration of singlet oxygen that is generated is directly proportional to the product of the light fluence rate (phi) and the concentration of the photosensitizer (Cs). Therefore, phiCs is an appropriate parameter for comparing the potential success of PDT protocols under these conditions. For a treatment of time t, the observed photodynamic effect resulting from singlet oxygen exposure should be directly related to phiCst. For high phiCs, the model predicts that oxygen depletion occurs within the tumor tissue. As a result, the photodynamic effect is no longer proportional to phiCst. We have expanded the model of Henning et al. to include the changes in oxygen concentration which occur within the capillary as blood flows through the tissue. Our new predictions with the mathematical model for optimal PDT treatment conditions are significantly different from those predicted by the previous models. Predictions of the model are given using parameters relevant for treatment of solid tumors with Photofrin.

Dihematoporphyrin Ether↗
PubMed1997

Anti-acetylcholinesterase antibody in myasthenic syndrome.

OBJECTIVE: To examine the relationship between antibodies to acetylcholinesterase and myasthenic syndrome. METHODS: Serum class specific antibodies to acetylcholinesterase and acetylcholine receptor were prepared with solid phase enzyme-linked immunosorbent assay in 51 patients with myasthenic syndrome, 31 controls with other neurological diseases (diseased controls) and 44 normal controls. RESULTS: The positive rate of anti-acetylcholinesterase antibody in patients with myasthenic syndrome was 25%, while the results of the other two control groups were negative. Furthermore, the positive rate in patients without myasthenia gravis was 45%, which was much higher than that (13%) in those with myasthenic gravis. CONCLUSION: Anti-acetylcholinesterase antibody may play a role in the pathogenesis of myasthenic syndrome.

Acetylcholinesterase↗
PubMed1997

[Purification and some properties of superoxide dismutase from Fusarium moniliform].

Superoxide dismutase from Fusarium moniliform was purified by the steps including heating, ammonium sulfate fractionation, Sephedax G-100 gel filtration and DEAE-Sephadex A-50 chromatography. The results showed that the enzyme was a Mn-SOD with the specific activity of 2640 U/mg and had two homogenous subunits whose molecular mass were 14.5 kD. The wave length of max. absorbing peak in ultraviolet spectrum was 276 nm which was not similar with other resource of SOD. The composition of amino acid was also analyzed.

Amino Acids↗
PubMed1996

Specific cleavage of alpha-fodrin during Fas- and tumor necrosis factor-induced apoptosis is mediated by an interleukin-1beta-converting enzyme/Ced-3 protease distinct from the poly(ADP-ribose) polymerase protease.

Interleukin-1beta-converting enzyme (ICE)/Ced-3 proteases play a critical role in apoptosis. One well characterized substrate of these proteases is the DNA repair enzyme poly(ADP-ribose) polymerase. We report here that alpha-fodrin, an abundant membrane-associated cytoskeletal protein, is cleaved rapidly and specifically during Fas- and tumor necrosis factor-induced apoptosis; this cleavage is mediated by an ICE/Ced-3 protease distinct from the poly(ADP-ribose) polymerase protease. Studies in cells treated with these apoptotic stimuli reveal that both fodrin and poly(ADP-ribose) polymerase proteolysis are inhibited by acetyl-Tyr-Val-Ala-Asp chloromethyl ketone and CrmA, specific inhibitors of ICE/Ced-3 proteases. However, fodrin proteolysis can be distinguished from poly(ADP-ribose) polymerase proteolysis by its relative insensitivity to acetyl-Asp-Glu-Val-Asp aldehyde (DEVD-CHO), a selective inhibitor of a subset of ICE/Ced-3 proteases that includes CPP32. DEVD-CHO protects cells from Fas-induced apoptosis but does not prevent fodrin proteolysis, indicating that cleavage of this protein can be uncoupled from apoptotic cell death. Moreover, purified fodrin is cleaved in vitro by CPP32 (but not by ICE) into fragments of the same size observed in vivo during apoptosis. These findings suggest that fodrin proteolysis in vivo may reflect the activity of multiple ICE/Ced-3 proteases whose partial sensitivity to DEVD-CHO reflects a limited contribution from CPP32, or an ICE/Ced-3 protease less sensitive than CPP32 to DEVD-CHO inhibition.

Apoptosis↗
PubMed1996

Activation of an interleukin 1 converting enzyme-dependent apoptosis pathway by granzyme B.

Cytotoxic T lymphocytes (CTL) can induce apoptosis through a granzyme B-based killing mechanism. Here we show that in cells undergoing apoptosis by granzyme B, both p45 pro-interleukin 1 beta converting enzyme (ICE) and pro-CPP32 are processed. Using ICE deficient (ICE -/-) mice, embryonic fibroblasts exhibit high levels of resistance to apoptosis by granzyme B or granzyme 3, while B lymphoblasts are granzyme B-resistant, thus identifying an ICE-dependent apoptotic pathway that is activated by CTL granzymes. In contrast, an alternative ICE-independent pathway must also be activated as ICE -/- thymocytes remain susceptible to apoptosis by both granzymes. In ICE -/- B cells or HeLa cells transfected with mutant inactive ICE or Ich-1S that exhibit resistance to granzyme B, CPP32 is processed to p17 and poly(ADP-ribose) polymerase is cleaved indicating that this protease although activated was not associated with an apoptotic nuclear phenotype. Using the peptide inhibitor Ac-DEVD-CHO, apoptosis as well as p45 ICE hydrolysis are suppressed in HeLa cells, suggesting that a CPP32-like protease is upstream of ICE. In contrast, p34cdc2 kinase, which is required for granzyme B-induced apoptosis, remains inactive in ICE -/- B cells indicating it is downstream of ICE. We conclude that granzyme B activates an ICE-dependent cell death pathway in some cell types and requires a CPP32-like Ac-DEVD-CHO inhibitable protease acting upstream to initiate apoptosis.

Animals↗