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Biomedical subjects

Z Feng

Publications and source records attributed to Z Feng.

At least 109 records · Page 6Linked to original sources
PubMed2000

[Anterior segment reconstruction and secondary posterior chamber intraocular lens implantation supported by fibromembrane].

OBJECTIVE: To evaluate the methods and effects of anterior segment reconstruction and secondary posterior chamber intraocular lens (IOL) implantation supported by fibromembrane in pupillary area. METHODS: Anterior segment was reconstructed in 86 eyes with different anterior segment disorders. Anterior segment reconstruction includes: partial penetrating keratoplasty, loosing front adhesion, suturing detached peripheral iris, loosing rear adhesion, reshaping pupil, perforating fibromembrane in the pupillary area. The IOL was secondarily implanted into the posterior chamber, and the patients were followed up in 3 - 32 months. RESULTS: The surgery was successful in all patients. The postoperative visual acuities in 71 eyes were >or= 0.5 (82.6%), including >or= 0.9 (39.5%) in 34 eyes and <or= 0.2 in 15 eyes (17.4%). After IOL implantation, the IOL correctly centered was in 68 eyes (79.1%), and deviated in 18 eyes (20.9%). Anterior chamber hemorrhage occurred in 5 eyes, 4 of them were recovered by conservative treatment and the blood membrane in another eye was sucked out through its primary incision. All patients had slight postoperative inflammation and without severe long term complications. CONCLUSION: With the support of enough fibromembrane in pupillary area, anterior segment reconstruction and secondary posterior chamber IOL implantation can be performed, thus IOL suture fixation is not necessary, and its associated complications can be avoided.

Adolescent↗
PubMed2000

[Cost-effectiveness analysis on two different measles immunization strategies].

OBJECTIVE: To seek the most economic and effective strategy in measles elimination in China, data of cost - effectiveness was analyzed to compare two different strategies of measles immunization (mass campaign and 2 - dose schedule) based on the data of population, economy and epidemiological features of measles in Henan province. METHODS: DALY was used as the measurement of effectiveness. Taking period from 1997 to 2020, the cost - effectiveness ratio (CER) was defined as the cost difference between mass campaign and 2 - dose schedule divided by the decline of DALYs if 2 - dose schedule had been substituted by mass campaign. RESULTS: Along with the increment of time, CER showed a descending trend then the mass campaign will have positive benefits after year 2013. CONCLUSION: Mass campaign is more cost - effective than 2 - dose schedule.

Cost-Benefit Analysis↗
PubMed2000

[Effects of excessive iodine on activity of enolase in hippocampus of developing mice].

OBJECTIVE: To study the effects of excessive intake of iodine for a long term on activity of enolase in hippocampal tissues of young mice. METHODS: A hyperiodine goiter animal model was replicated with drinking water with high level of iodine. Activity of neuron specific enolase (NSE) in hippocampal tissues was determined with enzyme-linked immunosorbent assay (ELISA) for young offspring of the first and the second generations of mice with hyperiodine goiter on the 7th, 14th and 21st day of age, respectively. RESULTS: Activity of enolase in young offspring of the first and second generation of mice with hyperiodine goiter was all lower than that in controls from the day of their birth to the 30th day after birth, and that at hippocampal tissues in young mice of the second generation was significantly lower than that of the first generation on the 14th day of age. CONCLUSION: Hyperiodine can decrease activity of NSE in the brain of mice. It suggests that hyperiodine can affect NSE, and thus interfere energy supply in the brain, resulting in disturbance of neuron development and brain function.

Animals↗
PubMed2000

[Study on the abnormal gene expression of inducible nitric oxide synthase (iNOS) in rabbit myocardium after high voltage electrical injury].

OBJECTIVE: To elucidate the effects of high voltage electrical injury on the mRNA expression of iNOS And endothelin-1 (ET-1) in rabbit myocardium. METHODS: Rabbits inflicted by high voltage electrical injury were employed as the model. Reverse transcription PCR (RT-PCR) and serum enzyme measurement were used in the detection of the expression levels of iNOS mRNA and ET-1 mRNA of rabbit myocardial tissue and plasma creatine kinase (CK) content. RESULTS: The expression of iNOS mRNA in rabbit myocardial tissue after high voltage electrical injury increased at 6 to 8 postburn hours (PBH) and decreased thereafter. The plasma contents of CK and ET-1 mRNA reached their peak values at 2 PBH. CONCLUSION: The increase of iNOS mRNA might protect myocardial tissue from electrical injury.

Animals↗
PubMed2000

[Preliminary isolation and identification of neurotrophic factors sensory neurons in spinal dorsal horn of embryonic chicken].

Our previous studies have demonstrated that the extract from dorsal horn of embryonic chicken can promote apparently the neurite growth of spinal ganglion during development. In this study, we investigated progressively the neurotrophic factors for primary sensory neurons in spinal dorsal horn. The tissues of spinal dorsal horn from five hundred Hamburger Stage-40 embryonic chickens were taken. After homogenization and centrifugation, the supernatant was subjected to SDS-polyacrylamide gel electrophoresis (SDS-PAGE) for analyzing the protein in dorsal horn. The simple protein band fishing by cell (SPBFC) technique was employed in finding the protein bands with neurons attached, and then such protein bands, were taken and transferred to nitric cellulose paper for Western hybridization analysis by antibody for NGF, BDNF, NT-3 and GDNF respectively. The results of SPBFC showed that some neurons were attached to gel within the scope of mobility relative front (Rf) 0.10-0.19, 0.30-0.35, 0.50-0.55, 0.60-0.67 and 0.90-0.94 respectively, indicating there were some neurotrophic factors for maintaining neuron survival in the above Rf scope. Moreover, the result of Western hybridization showed that the positive hybridization bands in each scope were that of NGF, BDNF, GDNF; NGF, BDNF, NT-3; NGF, BDNF, NT-3; NGF, NT-3 and BDNF, NT-3 respectively; indicating that the neurotrophic effect of spinal dorsal horn tissue on primary sensory neurons involves NGF, BDNF, NT-3 and GDNF. These also suggest that the neuronal survival effect in each Rf scope involves at least two or more neurotrophic factors.

Animals↗
PubMed2000

[Morphological observation on dorsal root ganglion neurons of embryonic chicken in vitro].

The aim of this study was to explore the developmental character of neurons from dorsal root ganglion (DRG) of embryonic chicken in vitro. The DRG neurons of Hamburger stage 35 were cultured and prepared at 0, 1, 2, 3, 4, 5, 7, 14 and 21 days respectively. The number of neuronal survival was counted at each cultured stage (observed area: 2.5 x 10(5) microns 2) and the morphological change of neurons in vitro was observed and compared with that of neurons in vivo. The results showed the counts of neuronal survival were 94 +/- 4, 83 +/- 6, 67 +/- 4, 65 +/- 7, 68 +/- 5, 71 +/- 9, 73 +/- 6, 22 +/- 4, and 0 respectively; the cultured neuronal shape during 48 h incubation was mainly oval or sphere, similar to that of neurons in vivo. However, the shape of some neurons changed into cone or shuttle after three days incubation, while the neuronal shape in vivo did not change. These findings indicate that only some of neurons can survive and grow and the lifetime is limited in vitro, on the other hand, the developmental character of neurons in vitro may be different from that of neurons in vivo.

Animals↗
PubMed2000

[Central nervous system calcium homeostasis imbalance and brain aging].

Brain aging is associated with a marked decline of memory. The calcium homeostasis imbalance hypothesis postulated that sustained changes in the regulation of intracellular Ca2+ concentration, [Ca2+]i are the major cause of brain aging. Aging may cause the increase of the [Ca2+]i through many mechanisms. These alterations would in turn affect the synaptic transduction, neurotransmitter release and signal transduction, cause memory deficit. This article reviewed the progress about this hypothesis in recent years.

Aging↗
PubMed2000

[The expression of trkC in spared dorsal root ganglion following unilateral dorsal root rhizotomy].

This study sought to explore the expression of trkC in spared dorsal root ganglion(DRG) following unilateral dorsal root rhizotomy. 15 cats were divided into three groups: the intact group, the 3-day and 10-day groups after operation (unilaterral L1-L5 DRG and L7-S2 DRG were sectioned, but L6 DRG was spared). The animals were sacrificed on the 3rd day and 10th day after operation, respectively. The L6 DRG from the three groups were taken and cut into frozen sections (20 microns). The sections were stained using specific antiserum for trkC by the immunohistochemical ABC method. The numbers of large sized neurons (> 57 microns) and small sized neurons (< 42 microns) for trkC-IR were counted respectively. The results showed that the number of positive large sized neurons for trkC of the 10-day group after operation decreased significantly than that of the intact group and the 3-day group after operation, while the number of positive small sized neurons for trkC of the 10-day group increased apparently than that of the intact group and the 3-day group after operation (P < 0.05). This experiment demonstrated that unilateral partial dorsal root rhizotomy could change the expression of trkC might in large neurons and small sized neurons, and the results suggested that trkC might involve in the spinal cord plasticity following partial dorsal root rhizotomy.

Animals↗
PubMed2000

Construction and analysis of cDNA library of Necator americanus third stage larvae.

OBJECTIVE: To obtain the genetic information on Necator americanus and to search for the purpose genes. METHODS: mRNA was isolated from the third stage larvae of Necator americanus maintained in hamsters. Double strand cDNA was synthesized and ligated to lambda ZAPII vector to construct the cDNA library. Expressed sequence tages (ESTs) were obtained by single pass sequencing of randomly isolated cDNA clones from the established library. RESULTS: A cDNA library of N. americanus was successfully constructed with high recombinant efficiency. The titer of unamplified library was 1 x 10(7). The insert size was about 750-3,000 bp. Of 11 ESTs obtained from the library, 7 have a significant homology with certain functional genes. CONCLUSION: A high quality and high representative cDNA library of N. americanus was constructed at the first time and some functional genes were identified from the library by ESTs.

Animals↗
PubMed2000

[Observation on specific IgG4 antibody of schistosomiasis patients before and after treatment].

OBJECTIVE: To observe the alteration of specific IgG4 antibody of schistosomiasis patients before and after treatment. METHODS: ELISA. RESULTS: The SEA-IgG4 and AWA-IgG4 positive rates of 27 schistosomiasis cases were 96.3% and 100%, respectively, their average OD values were 1.62 and 0.72. 6 months post treatment 18 cases were followed up, the positive rates were 94.4% and 100%, respectively, their average OD values were 1.06 and 0.56, respectively. 12 months post treatment all cases were followed up, the positive rates of SEA-IgG4 and AWA-IgG4 were 96.3% and 92.6%, respectively, their average OD values were 0.99 and 0.58, respectively. CONCLUSION: No obvious changes were found in the SEA-IgG4 and AWA-IgG4 positive rates of 27 schistosomiasis cases before and after treatment, whereas the antibody level of specific IgG4 was decreased.

Adult↗
PubMed2000

Gene sequencing for identification of Paragonimus eggs from a human case.

OBJECTIVE: To identify the etiologic agent from a paragonimiasis patient using molecular techniques. METHODS: The complete nuclear ribosomal DNA second internal transcribed spacer (ITS2) gene sequence of eggs in sputum from a paragonimiasis patient was obtained by directly auto-sequencing its PCR product. ITS2 genes from eggs of Paragonimus westermani and Pagumogonimus skrjabini (both from animal hosts) were also sequenced for comparison. In addition, morphological comparisons were made with the eggs of the two species. RESULTS: The ITS2 gene from the human case was 100% identical with the sequence from the eggs of P. westermani from an experimentally infected dog but only 92% identical with the sequence from the eggs of P. skrjabini. Morphologically, the eggs from the human case more resembled those from P. westermani infected dog. CONCLUSION: The patient was diagnosed to be suffered from paragonimiasis westermani by gene sequence analysis.

Animals↗
PubMed2000

[Circulating antigen detection in schistosomiasis japonica patients by sandwich ELISA using polyclonal and monoclonal antibodies].

OBJECTIVE: To detect circulating antigen in the patients with schistosomiasis. METHODS: Polyclonal antibody(PcAb)-monoclonal antibody(McAb) sandwich ELISA. RESULTS: Sera from 150 patients with schistosomiasis were detected, the average sensitivity was 84.7%(72.0%-91.0%). No false positive reaction was detected in 40 normal controls and none but 2 patients(2/10) with paragonimiasis showed cross reactions among 74 cases with other parasitic infections. CONCLUSION: PcAb-McAb sandwich ELISA is a relatively ideal method for circulatling antigen detection.

Animals↗
PubMed2000

[Effects of salvianolic acid B on beta-amyloid peptide neurotoxicity of primary cultured fetal rat cortical neurons].

AIM: To study the roles of nitric oxide (NO) and nitric oxide synthase (NOS) on the glutamate (Glu) and beta-amyloid peptide [beta-AP (1-40)] mediated neurotoxicity in primary cultured fetal rat cortical neuron and the neuroprotective effects of salvianolic acid B (Sal B) against the beta-AP (1-40) and its mechanism of action. METHODS: With application of specific agonist and antagonist of NOS, establishment of the sodium nitroprusside (SNP), Glu and beta-AP (1-40) neurotoxicity model, the cell viability, lactate dehydrogenase (LDH) efflux and NO release were detected by using morphological observation, MTT stain, spectrophotometric measurement and Griess method, respectively, in primary cultured fetal rat cortical neurons. RESULTS: Glu and beta-AP (1-40) were shown to increase the NO release of the neuron. Furthermore, nNOS was found to play an important role in the neurotoxicity of glutamate, iNOS may probably be involved in the neurotoxicity of beta-AP (1-40). Sal B (0.01, 0.10, 1.00 microgram.L(-1)) was shown to increase the cell viability, decrease the LDH release rate and inhibit NO release in a dose-dependent manner. CONCLUSION: These results suggest that the neurotoxicity of Glu and beta-AP(1-40) may be partly mediated through different types of NOS. Sal B was found to prevent the beta-AP(1-40) toxicity by directly or indirectly decreasing NO release.

Amyloid beta-Peptides↗
PubMed1999

Identifying the site of initial tertiary structure disruption during apomyoglobin unfolding.

Structural characterization of protein unfolding intermediates [Kiefhaber et al. (1995) Nature 375, 513; Hoeltzli et al.(1995) Proc. Natl. Acad. Sci. U.S.A. 92, 9318], which until recently were thought to be nonexistent, is beginning to give information on the mechanism of unfolding. To test for apomyoglobin unfolding intermediates, we monitored kinetics of urea-induced denaturation by stop-flow tryptophan fluorescence and quench-flow amide hydrogen exchange. Both measurements yield a single, measurable kinetic phase of identical rate, indicating that the reaction is highly cooperative. A burst phase in fluorescence, however, suggests that an intermediate is rapidly formed. To structurally characterize it, we carried out stop-flow thiol-disulfide exchange studies of 10 single cysteine-containing mutants. Cysteine probes buried at major sites of helix-helix pairing revealed that side chains throughout the protein unpack and become accessible to the labeling reagent [5, 5'-dithiobis (2-nitrobenzoic acid)] with one of two rates. Probes located at all helical-packing interfaces-except for one-become exposed at the rate of global unfolding as determined by fluorescence and hydrogen exchange measurements. In contrast, probes located at the A-E helical interface undergo complete thiol-disulfide exchange within the mixing dead time of 6 ms. These results point to the existence of a burst-phase unfolding intermediate that contains globally intact hydrogen bonds but locally disrupted side-chain packing interactions. Dissolution of secondary and tertiary structure are therefore not tightly coupled processes. We suggest that disruption of tertiary structure may be a stepwise process that begins at the weakest point of the native fold, as determined by native-state hydrogen-exchange parameters.

Animals↗
PubMed1999

NF-kappaB/Rel proteins are required for neuronal differentiation of SH-SY5Y neuroblastoma cells.

The expression, cellular localization, and activation of the NF-kappaB/Rel transcription factors are altered during neuronal differentiation, but the significance is unclear. Here we investigate the requirement for NF-kappaB/Rel proteins in neuronal differentiation. SH-SY5Y neuroblastoma cells were induced to differentiate with retinoic acid (RA) or 12-O-tetradecanoylphorbol 13-acetate (TPA), and differentiation was demonstrated by morphological criteria and the enhanced expression of Bcl-2. NF-kappaB was transiently activated after the addition of the differentiation inducers before the morphological signs of differentiation and the enhanced Bcl-2 synthesis. The onset of NF-kappaB activation coincided with a significant reduction in the amount of only one of four NF-kappaB-inhibitory proteins examined (I-kappaBbeta). In contrast, NF-kappaB activation and the reduction in I-kappaBbeta failed to occur in SH-SY5Y cells transformed with I-kappaBalphaM, a dominant-negative inhibitor of NF-kappaB/Rel proteins. These I-kappaBalphaM-expressing cells failed to differentiate into neuronal cell types when treated with RA or TPA, and the increased Bcl-2 synthesis was blocked. Therefore, NF-kappaB/Rel proteins are required for neuronal differentiation of SH-SY5Y neuroblastoma cells.

Cell Differentiation↗
PubMed1999

The Women's Health Trial Feasibility Study in Minority Populations: changes in dietary intakes.

This randomized clinical trial examined the feasibility of low-fat dietary interventions among postmenopausal women of diverse backgrounds. During 1992-1994, 2,208 women aged 50-79 years, 28% of whom were black and 16% Hispanic, enrolled at clinics in Atlanta, Georgia, Birmingham, Alabama, and Miami, Florida. Intervention/support groups met periodically with a nutritionist to reduce fat intake to 20% of energy and to make other diet modifications. At 6 months postrandomization, the intervention group reduced fat intake from 39.7% of energy at baseline to 26.4%, a reduction of 13.3% of energy, compared with 2.3% among controls. Saturated fatty acid and cholesterol intakes were reduced, but intakes of fruits and vegetables, but not grain products, increased. Similar effects were observed at 12 and 18 months. Black and non-Hispanic white women had similar levels of reduction in fat, but the decrease in Hispanic women was less. Changes did not vary significantly by education. While bias in self-reported intakes may have resulted in somewhat overestimated changes in fat intake, the reported reduction was similar to the approximately 10% of energy decrease found in most trials and suggests that large changes in fat consumption can be attained in diverse study populations and in many subgroups.

Aged↗