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Biomedical subjects

Fan Lu

Publications and source records attributed to Fan Lu.

At least 37 records · Page 2Linked to original sources
PubMed2005

Only male matrilineal relatives with Leber's hereditary optic neuropathy in a large Chinese family carrying the mitochondrial DNA G11778A mutation.

We report here the characterization of a five-generation large Chinese family with Leber's hereditary optic neuropathy (LHON). Very strikingly, six affected individuals of 38 matrilineal relatives (17 females/21 males) are exclusively males in this Chinese family. These matrilineal relatives in this family exhibited late-onset/progressive visual impairment with a wide range of severity, ranging from blindness to normal vision. The age of onset in visual impairment varies from 17 to 30 years. Sequence analysis of the complete mitochondrial genome in this pedigree revealed the presence of the G11778A mutation in ND4 gene and 29 other variants. This mitochondrial genome belongs to the Southern Chinese haplogroup B5b. We showed that the G11778A mutation is present at near homoplasmy in matrilineal relatives of this Chinese family but not in 164 Chinese controls. Incomplete penetrance of LHON in this family indicates the involvement of modulatory factors in the phenotypic expression of visual dysfunction associated with the G11778A mutation. However, none of other mtDNA variants are evolutionarily conserved and implicated to have significantly functional consequence. Thus, nuclear modifier gene(s) or environmental factor(s) seem to account for the penetrance and phenotypic variability of LHON in this Chinese family carrying the G11778A mutation.

Asian People↗
PubMed2005

Interaction of restin with transcription factors.

Restin, a member of melanoma-associated antigen superfamily gene, was first cloned from differentiated leukemia cell induced by all trans-retinoic acid, and was able to inhibit cell proliferation, but the molecular mechanism was not clear. Since Restin was localized in cell nucleus, and its homolog member, Necdin (neuronal growth suppressor factor), could interact with transcription factors p53 and E2F1, we proposed that Restin might also function as Necdin through interacting with some transcription factors. In this study, transcription factors p53, AP1, ATFs and E2Fs were cloned and used in the mammalian two-hybrid system to identify their interaction with Restin. The results showed that only ATF3 had a strong interaction with Restin. It is interesting to know that ATF3 was an important transcription factor for G1 cell cycle initiation in physiological stress response. It was possible that the inhibition of cell proliferation by Restin might be related with the inhibition of ATF3 activity.

Animals↗
PubMed2005

[Cloning and expression of a novel gene restin and preparation of antisera against the recombinant restin].

AIM: To clone a new human gene, restin, from retinoic acid-treated promyelocytic cell line HL-60, express the protein in E.coli and prepare the antisera against the protein. METHODS: The restin gene was amplified from retinoic acid-treated promyelocytic cell line HL-60 by RT-PCR and cloned into a prokaryotic expression vector. The recombinant restin was induced to express in E. coli by temperature. After preliminary purification by SDS-PAGE, the restin protein was used to immunize rabbits to obtain antisera. The titers and specificity of the rabbit anti-restin antisera were tested by Western blot and immunofluorescence analysis. RESULTS: Recombinant restin with M(r) being about 26,000 was highly expressed in E. coli. The titers of the anti-sera to restin ranged from 1:100 to 1:800. Immunofluorescence analysis showed that restin distributed mainly in the nuclei of COS-7 cells. CONCLUSION: We successfully prepared the antisera against restin, which are useful for further investigation of biological functions of restin.

Animals↗
PubMed2005

[Passive remote sensing of VOC in atmosphere by FTIR spectrometry].

The paper expatiates the passive remote sensing experiment of VOC in atmosphere by FTIR spectrometry, a mode of simulated spectra for pollution gas in a complicated environment is proposed, and the detecting limit of passive FTIR remote sensing is discussed. Using this measurement technique and the data analysis method, the authors can obtain column density and effective radiation temperature of target-gas that does not require a previously measured background spectrum.

Air Pollutants↗
PubMed2005

[Study on UV-visible DOAS system based on photodiode array (PDA)].

A long-path differential optical absorption spectroscopy (DOAS) system is introduced. A photodiode array is employed as the detector to replace the complicated SD detector which consists of a PMT and a slotted disk. The properties of the detector and the spectrometer unit such as offset, dark current, noise, linearity, resolution, and wavelength range were measured. This system was also tested to measure SO2 and NO2 in the atmosphere. The detection limits of this system for SO2, and NO2 over a 713 m light path were determined.

Algorithms↗
PubMed2004

The structural basis for autoinhibition of FLT3 by the juxtamembrane domain.

FLT3 is a type III receptor tyrosine kinase that is thought to play a key role in hematopoiesis. Certain classes of FLT3 mutations cause constitutively activated forms of the receptor that are found in significant numbers of patients with acute myelogenous leukemia (AML). The mutations occur either in the activation loop, for example, as point mutations of Asp835 or as internal tandem duplication (ITD) sequences in the juxtamembrane (JM) domain. To further understand the nature of FLT3 autoinhibition and regulation, we have determined the crystal structure of the autoinhibited form of FLT3. This structure shows the autoinhibitory conformation of a complete JM domain in this class of receptor tyrosine kinases. The detailed inhibitory mechanism of the JM domain is revealed, which is likely utilized by other members of type III receptor tyrosine kinases.

Amino Acid Sequence↗
PubMed2004

[Culture and study on melanogenesis of mongolian uveal melanocytes in vitro].

OBJECTIVE: To establish cell lines of Mongolian uveal melanocytes from adult donor eyes, and to study melanogenesis of these cells in vitro. METHODS: After removal of pigment epithelium, UM were isolated by trypsin-collagenase digestion. Isolated cells were cultured with F12 medium supplemented with fetal bovine serum, basic fibroblast growth factor, isobutylmethylxanthine and cholera toxin. Melanin content was measured by spectrophotometer. Melanin production was calculated by a formula. The antibodies used in immunocytochemical studies were anti-cytokeratin and anti-S-100 antibodies. RESULT: Pure melanocytes cultures were obtained by this method. All of the cells in the cultures stained positively with antibodies to S-100, but not cytokeratin, indicating that they were pure culture of UM. In the growing UM, melanin content was (79.83 +/- 36.20) pg/cell (mean +/- SD). Melanin production was (11.44 +/- 5.77) pg per cell/24 h. CONCLUSION: Uveal melanocytes from Mongolian eyes are successfully cultured. Cultured uveal melanocytes can synthesize melanin in vitro. Melanin content and melanin production of Mongolian UM lie between those from black and Caucasian eyes.

Adult↗
PubMed2004

[Sutureless lamellar keratoplasty by microkeratome combined with fibrin tissue adhesive in rabbits].

OBJECTIVE: To evaluate the feasibility and safety of sutureless lamellar keratoplasty by microkeratome combined with fibrin tissue adhesive. METHODS: Twenty-four New Zealand white rabbits were divided into two groups, the donor grafts and recipient beds were made by the microkeratome, the grafts were glued over the stoma bed using the commercial product Tisseel in one group; and grafts without tissue adhesive were used as the control group. Corneal refractive power was measured by automated keratometer preoperatively and in 3 days, 2 weeks, 1 and 3 months postoperatively. Rejection and cornea transparency were observed. Confocal microscopy was used to observe corneal wound healing response and to measure the keratocyte and endothelium densities in vivo. Corneal wound healing was also evaluated using light and fluorescence microscopy. RESULTS: Ninety-two percent (11/12 eyes) of the glued grafts were retained in the Tisseel group, whereas all grafts were lost in the control group. All survived grafts were clear 1 month after surgery. However, in the control group, severe haze in the grafts occurred 2 weeks postoperatively. Confocal microscopy showed that there was a significant decrease of the keratocyte density surrounding the lenticule-host interface, and no changes occurred in the posterior keratocyte and endothelium. Histopathologic observations demonstrated the presence of a line of amorphous eosinophilic substance in the lenticule-host interface at 3 days after surgery, but the line disappeared after 1 month. Fluorescence microscopy showed no detectable regenerated stromal tissue. CONCLUSIONS: This initial study demonstrates sutureless optical lamellar keratoplasty performed by microkeratome combined with fibrin tissue adhesive is a simple and safe technique. Stromal wound healing response to this surgery is minimal. Fibrin tissue adhesive has no influence on the cornea optical property.

Animals↗
PubMed2004

[Effects after orthokeratology on corneal topography and monochromic wavefront aberration].

OBJECTIVE: To assess the corneal topography and monochromatic wavefront aberration among subjects using orthokeratology. Changes of ocular optical quality and related visual functions induced by corneal topography were studied. METHODS: Twenty-five young myopic subjects (50 eyes) were recruited with myopia from -1.75 approximately -4.75 D. Orthokeratology lens were fitted at the initial visit with overnight wear program. Subjective refraction, corrective visual acuity, corneal topography and slit lamp examination were performed before and 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks and 12 weeks after the fitting of orthokeratology lens. The monochromic wavefront aberration was measured in initial visit and after 12 weeks. RESULT: The best corrected visual acuity was reduced significantly from (-0.0628 +/- 0.0286) LogMAR (before orthokeratology) to -0.0120 +/- 0.0318 (12 weeks after orthokeratology) (F = 17.821, P < 0.001). Root-mean-square (RMS) of wavefront aberration increased significantly from (0.5766 +/- 0.4771) micro m (before orthokeratology) to (1.3731 +/- 0.8039) micro m (12 weeks after orthokeratology) (F = 36.513, P < 0.001). RMS of Zernike function of each order was increased as well. The rate of eccentric in posterior surface of corneal increased significantly after the using of orthokeratology lens. CONCLUSIONS: Orthokeratology is one of the effective methods for reducing myopia temporarily. However, the best corrected visual acuity is decreased after using of orthokeratology. The increase of aberration induced by orthokeratology can be the cause of reduction of ocular optical quality.

Adolescent↗
PubMed2004

[Construction of a DNA vaccine against extracellular domain 1-3 of Flk1 and its inhibitory effect on growth of liver cancer cell line H22].

BACKGROUND & OBJECTIVE: Angiogenesis plays an important role in the growth,invasion,and metastasis of most solid tumors. Vascular endothelial growth factor (VEGF) and its receptor flk-1 play a key role in tumor angiogenesis. Blocking VEGF-flk1 pathway may inhibit tumor growth. This study was to construct a DNA vaccine against extracellular domain 1-3 of flk1,and test its inhibitory effect on growth of liver cancer cell line H22. METHODS: Extracellular domain 1-3 of flk1 was cloned by reverse transcriptase-polymerase chain reaction (RT-PCR),and inserted into plasmid pcDNA3.1(+) to construct vaccine pcDNA3.1(+)-flk1-domain 1-3. The vaccine was transfected into COS7 cells,and protein expression of flk1-domain 1-3 was detected by Western blot. Standard 4-h (51)Cr releasing test was used to detect specific cytotoxic T lymphocyte (CTL) activity in vaccine-inoculated mice. To test vaccine's preventive effect,mice were divided into V,P, and S groups,treated with vaccine,pcDNA3.1(+), and saline, respectively. H22 cells were inoculated into mice 10 days later. The tumor size, tumor weight, mice survival time, tumor latent period, and microvessel density were recorded and analyzed. RESULTS: Extracellular domain 1-3 of flk1 was cloned,and vaccine against it was constructed,both have been proved by DNA sequencing and comparing with data in GenBank. A protein of 44 kDa,which is consisted with flk1-domain 1-3 protein,expressed in COS7 cells inoculated with the DNA vaccine,specific CTL activity in these cells raised. After inoculated with H22 cells,tumor latent time of V group was (5.2+/-0.9) d,of P group was (4.0+/-0.7) d,of S group was (3.8+/-0.6) d; survival time of V group was (24.5+/-3.2) d,of P group was (14.7+/-2.6) d,of S group was (14.3+/-2.0) d; microvessel density of V group was 10.1+/-1.7,of P group was 27.3+/-3.3,of S group was 25.3+/-4.6; tumor weight of V group was (1.4+/-0.1) g,of P group was (1.8+/-0.2) g,of S group was (1.8+/-0.2)g. In comparison among groups,all data in V group were significantly different from P group and S group (P< 0.05),no significant difference existed between P group and S group (P >0.05). CONCLUSION: The DNA vaccine against flk-1 may stimulate potent specific CTL activity, and inhibit growth of H22 cells by its anti-endothelial cell property.

Animals↗
PubMed2003

Monochromatic wavefront aberrations in the human eye with contact lenses.

PURPOSE: The aim of this study was to investigate the effect of contact lenses on the optical performance of the eye by measuring wavefront aberrations for the eyes with or without contact lenses. METHOD: A sensitive aberrometer was used to measure wavefront aberrations for 54 eyes in 27 subjects for three conditions: with no contact lens (non-CL), with soft-contact lenses (soft-CL) and with rigid gas permeable contact lenses (RGP-CL). The root mean square (RMS) value of the wavefront aberrations and Zernike aberrations were calculated. RESULTS: A change in the RMS values of wavefront aberrations with CL wear was observed for every eye. The change in wavefront aberrations with CL wearing was found to vary substantially from individual to individual. Relative to the mean RMS value of the group for the non-CL condition, the mean RMS value was increased for the soft-CL condition and was significantly reduced for the RGP-CL condition. A significant increase in mean RMS for the soft-CL condition was found when astigmatisms were removed. Although soft-CL wearing resulted in significant increases in higher orders of Zernike aberrations (fourth, fifth, and higher), the RGP-CL condition led to a significant decrease in second-order Zernike aberrations. For the eyes with low wavefront aberrations in the non-CL condition, either soft-CL wearing or RGP-CL wearing results in increases in the RMS values. CONCLUSION: Contact lens wearing, either with soft lenses or the RGP lenses, causes changes in the wavefront aberrations of the eye. The changes in wavefront aberrations vary substantially from eye to eye. Although soft-CL wearing tends to induce more higher-order aberrations, RGP-CL effectively reduces the astigmatisms. Both soft-CL and RGP-CL induce more aberrations for the eyes that have low wavefront aberrations. The change in wavefront aberrations due to contact lens wearing may explain the changes in visual performance for contact lens wearers reported previously.

Adolescent↗
PubMed2003

[A study on the estimation of the size of male homosexual population].

OBJECTIVE: To study the practical survey method on estimating the size of male homosexual population. METHODS: Nine male homosexual gathering spots were selected and three methods as division method, capture-mark-recapture method and multiplier method were applied in counting the numbers of homosexual men in one city in Sichuan province. RESULTS: Number of counting through division method was 877 and the three numbers through capture-mark-recapture method were 1408, 1207 and 949 respectively. However, appropriate data was not obtained by multiplier method. CONCLUSIONS: Division method was easy to operate with its high credibility, but costly. Capture-mark-recapture method was less costly less both in capital and time, and the results could be testified to each other. Multiplier method should be modified before applied to obtain reliable information.

China↗
PubMed2002

[Identification of a resistance gene to bacterial blight (Xanthomonas oryzae pv. oryzae) in a somaclonal mutant HX-3 of indica rice].

Using the mature embryo of a susceptible rice variety Minghui 63 as the explant, we have obtained a somaclonal mutant HX-3 through selection in vitro, which has showed resistance to bacterial blight. In 8 successive years, the resistance of R1 to R9 generations of HX-3 was identified by ZJ173, a typical bacterial blight strain in Yangtsu River valley, and the results showed that the resistance of HX-3 was stable and heritable. Genetic analysis also indicated that the resistance of HX-3 to bacterial blight was under a dominant gene controlling. Using 32 bacterial blight strains collected in China, Philippines and Japan, the resistance spectrum of HX-3 and other 13 testers with different major dominant resistance genes were tested. Results of 2 years (1999-2000) experiment showed that HX-3 had a broad resistance spectrum, which seemed to be different with those of the other dominant resistance genes identified. Allelic tests were also conducted by crossing HX-3 with IRBB4, IRBB7, CBB12 and IRBB21, and the F2 populations of each of the 4 crosses demonstrated resistant and susceptible plant segregation, indicating that the resistance gene in HX-3 different from Xa-4, Xa-7, Xa-12 and Xa-21. All these results proved that there was a new resistance gene in HX-3. We have designated the new gene as Xa-25(t).

Disease Susceptibility↗
PubMed2002

Cloning expression in E.coli and biological activity of human thymosin beta(4).

The cDNA thymosin beta(4) was synthesized by combining of chemical and enzymatic methods. First, two complement fragments of thymosin beta(4) cDNA were synthesized by DNA synthesizer, and then denatured, annealed and extended by DNA polymerase. This fragment of thymosin beta(4) was then inserted into the EcoRV and HindIII restriction endonuclease site of an expression plasmid pLDH4 (a kind of E.coli plasmid) by blunt and cohesive ligations. Finally, the recombinant plasmid which expressed thymosin beta(4) was screened by digestion and DNA sequencing. This recombinant plasmid highly expressed the thymosin beta(4), which accounted for 30% of total bacteria proteins. By salting out and chromatography, a 95% purity of recombinant thymosin beta(4) was obtained. Biological assay indicated that the recombinant thymosin beta(4) could induce lymphocyte proliferation and differentiation.

Cell Differentiation↗
PubMed2002

[A preliminary study on development of human visual system in fetus by DiI-tracing].

OBJECTIVE: To reveal the morphological features and dynamic processes of the development of inter-connections in the retina, lateral geniculate nucleus (LGN), superior colliculus (SC) and visual cortex (VC) in human fetal life by using a fluorescent tracer, 1, 1'-dioctadecyl-3, 3, 3', 3'-tetramethylin-docarbocyanine perchlorate (DiI). METHODS: DiI was embedded into the optic tract, brachium of superior colliculus and subplate of visual cortex in fixed postmortem human tissues of 7 fetuses. The tissue was incubated at 37 degrees C for 4 to 10 weeks (ws). After DiI had satisfactorily diffused via axons of the visual system, the tissue was sectioned, mounted and observed under a confocal laser scanning microscope. RESULTS: In 12 week-fetus, retinogeniculate axon has already reached LGN, but there was no cellular lamination. After embedment, axons from retina arrived at SC, and the fibers were distributed along the dorsal part of the SC. At 12 and 22 ws, there were subplates under visual cortex. CONCLUSION: The retinogeniculate axon reaches LGN before 12 ws and forms cellular lamination after 12 ws. The axon from retina reaches SC before 12 ws. The subplate under visual cortex forms before 12 ws and disappears after 22 ws. DiI can be easily and effectively used to label the axon of visual system of human fetus to study the prenatal development of human visual pathway.

Axons↗