Biomedical subjects

J Xu

Publications and source records attributed to J Xu.

At least 739 records · Page 41Linked to original sources

PubMed1998

[Interventional thrombolysis for treatment of intravascular thrombus].

OBJECTIVE: To evaluate the interventional thrombolysis for treatment of untravascular thrombus and disscuss the problems of its clinical use. METHODS: 18 patients with intravascular occlusive disease were treated with pulsed-spray thrombolysis(PST). The concentration of urokinase was 10,000 U/ml. The dose of urokinase was 10,000 U/min, the total dose was from 300,000 U to 800,000 U, and the average dose was 380,000 U. RESULTS: In 18 cases, 14 were obtained thrombolysis completely(77.8%), the cases of thrombolysis partly and unaffected were 2(11.1%) and 2(11.1%) in number respectively. The mean time of thrombolysis was 2.8 hours. CONCLUSION: The treatment of thrombolysis is highly beneficial to the patients with intravascular occlusive disease.

Adult↗

PubMed1998

Selection of new Epitopes from monovalent displayed phage octapeptide library.

A library of 2 x 10(7) random octapeptides was constructed by use of phagemid-based monovalent phage display system. The randomly synthesized degenerated oligodeoxyribonucleotides (oligos) were fused to the truncated g III (p230-p403). Sequence analysis of 11 randomly chosen clones suggested that the degenerated inserts and its deduced amino acid (aa) sequences are randomly distributed. The library was used to select binding peptides to the monoclonal antibody (mAb) 9E10, which recognizes a continuous decapeptide epitope of denatured human c-myc protein. After four to five rounds of panning, most of the eluted clones could bind to 9E10. Sequence analysis of the selected positive clones indicated that the binding sequences could fall into two classes, one class (clone 1) shares a consensus motif, ISE x x L, with c-myc decapeptide; and the sequences of the other class are entirely different. The binding of both classes to 9E10 could be specifically inhibited by free c-myc decapeptide. The immunogenicity of the phage peptide was further investigated by construction of multivalent displayed phage peptides and immunization of animals with or without adjuvant. ELISA and competitive ELISA showed that anti-serum from both mice and rabbit immunized with either clone could bind to the original antigen, c-myc decapeptide. These results denote that in spite of the dissimilarity of the selected peptides with c-myc decapeptide, they are capable of inducing similar immune respones in vivo, thus actually mimicking the antigen epitope.

Amino Acid Sequence↗

PubMed1998

[The responses of the microvasculature of the periodontal ligament to horizontal force].

OBJECTIVE: The purpose of this study is to examine the responses of the microvasculature in periodontal ligament(PDL) to horizontal force. METHODS: Using ink injections and celloidin embed, serial sections were cut, then observed by light micrascope, quantitative analysis was conducted by the picture-analysis instrument. Vascular corrosion casts were prepared and examined by scanning electron microscopy. The forth premolars of dogs were pulled by 200 g force in a mesial direction for two hours, and the pressure effects in different positions were demonstrated. RESULTS: The section area of the microvasculature per unit PDL area is obvious larger on the tension sides than on the pressure sides. There is not an obvious distinction on the pressure sides between the experiment groups and control groups. However, there are clear distinctions in the one-third of cervical, and apical segment on the tension sides between the experiment groups and control groups. CONCLUSION: The microvascular changes in PDL had importance to the cushioning effect of PDL when a teeth received a kind of force in a short-time.

Animals↗

PubMed1998

[Computer aided photocclusion analysis of traumatic occlusion].

OBJECTIVE: This study was designed to analyse traumatic occlusion quantitatively. METHODS: A photocclusion method using computer image processing technique is described, the processing software provide the occlusal contact area, contact point numbers, contact force, maximum stress, and average stress distribution of all teeth by tables and figures. RESULTS: (1) The traumatic contact area was larger and contact force was greater than that of the normal occlusal contact. (2) There was an irregularity force distribution from molars to incisal area. (3) The symmetrical distribution of contact forces and contact areas were destroyed. CONCLUSION: Computer aided-photocclusion method can be used to diagnose traumatic occlusion.

Dental Occlusion, Traumatic↗

PubMed1998

[Retroperitoneal laparoscopic unroofing of renal cyst: use of close method].

OBJECTIVE: To study the close method of retroperitoneal laparoscopic unroofing of renal cyst. METHOD: A close method retroperitoneal laparoscopic unroofing of renal cyst was attempted in 35 cases between May 1995 and December 1996. The age of the patients ranged from 30 to 72 and the cyst size from 4.0 to 9.3 cm. RESULTS: The operative procedure took around 50 minutes. After a 1 - 18 month follow up, we observed the disappearance of all renal cysts. CONCLUSION: The laparoscopic procedure renders less trauma and discomfort to the patients and may be better indicated for symptomatic, simple renal cysts.

Adult↗

PubMed1998

[Reoperation for recurrent carcinoma of the esophagus and cardia].

OBJECTIVE: To review the experience of reoperation for recurrent carcinoma of the esophagus and cardia. METHOD: Between 1979 and 1996, 44 patients with recurrent esophageal and cardiac cancer after the first operation underwent reoperation. Among them, 21 had esophageal cancer and 23 cardiac cancer. 36 patients were male and 8 female, with age ranged from 42 to 68 years. RESULT: The resectability rate was 77.2% (34/44) and the hospital mortality rate was 5.8%. Postoperative complications occurred in 7 patients with a morbidity of 20.5%. Pathologically, previous anastomotic relapse was seen in 26 patients, recurrent lesion of residual esophagus in 7, and recurrent cancerous residue at the esophageal bed in 1. 15 patients (44%) showed lymph node metastasis. Follow-up showed that 4 patients survived for 5 years, 4 for 3 years, and 3 for 2 years. 15 patients died within one year after reoperation. CONCLUSION: The recurrence of esophageal and cardiac cancer after first operation is not a contraindication to reoperation, but careful preoperative assessment and patients' selection should become an integral part of the evaluation of these patients.

Adult↗

PubMed1998

[Experimental study on regenerative capacity and form of corneal endothelial cells in the primate].

OBJECTIVE: To investigate the regenerative capacity and form of the corneal endothelial cells of the primate. METHODS: Chromosome, HE stainings and autoradiography were made for the cornea of human and monkey. RESULTS: After trauma, corneal endothelial cells of the adult monkey in vivo showed regenerative power. The regenerative form of corneal endothelial cells of the adult, infant and fetal primate was amitosis under both physiologic and pathologic conditions. CONCLUSION: The corneal endothelial cells of the primate have regenerative power, and the form is amitosis.

Adult↗

PubMed1998

[An experimental study on formation of cellular membrane on the surface of implanted posterior chamber intraocular lens].

OBJECTIVE: To observe the cellular reaction and membrane formation on the surface of intraocular lens (IOL) implanted in rabbit eyes and discuss the mechanism of early postoperative membrane formation and biological action. METHODS: 20 adult pigmented rabbit eyes were given posterior chamber IOL implantation. IOLs were extracted on the postoperative 1st, 3rd, 7th, 14th and 28th days respectively. Samples were observed under light microscope and scanning electron microscope (SEM). RESULTS: Macrophages on the surface of IOL had transformed into fibroblast-like cells and the formation of eosinophilic membrane had occurred on the 3rd day after operation with tiny thread-like things interwoven among cells forming net-like supporting membrane under SEM. CONCLUSION: It infers that the membrane is a kind of fibrinous film secreted by fibroblast-like cells and the cells involved in reaction are the biological foundation of membrane formation; this membrane will prohibit the serious cellular reaction at the end and keep IOL transparent.

Animals↗

PubMed1998

[The survey of anterior chamber angle in a population of middle and old age].

OBJECTIVE: To determine the condition of anterior chamber angle in a population of middle and old age, and afford data for screening of angle closure glaucoma. METHODS: Two hundred people aged 50 years or older were selected by random sampling in four districts of Doumen county. The anterior chamber angle of all people was evaluated by Goldmann one-mirror gonioscope, and the angle was graded according to the Spaeth and Shaffer's grading system. RESULTS: Three hundred ninety eyes were examined, 12% (inferior angle) to 30% (superior angle) were Shaffer's grade <or= 2. 11.3% (inferior) to 26.4% (superior) were anterior bowing of the peripheral portion of the iris, 27.7% (inferior) to 42.6% (superior) were iris insertion into seleral spur. The three aspects of the angle had significant differences in sex and age. CONCLUSION: The survey shows that the percentage of people with occludable angles increases significantly with age, and women with occludable angles are more than men. This result is important for us to make screening strategy of primary angle-closure glaucoma.

Adult↗

PubMed1998

[Determination of digoxin-like immunoreactive substances in sera of 15 elder patients with cardiac insufficiency].

The presence of a higher concentration of digoxin-like immunoreactive substances (DLIS) in human serum have been reported in a number of pathophysiological conditions. DLIS can react with anti-digoxin antibodies when determination of serum digoxin was performed with immunoassay. It may falsely elevate the serum digoxin concentration and is troublesome in the therapeutic monitoring of digoxin. The apparent digoxin concentrations (DLIS) in serum were determined in 15 elder patients with cardiac insufficiency by fluorescence polarization immunoassay (FPIA). The lowest measurable concentration, defined as the concentration that could be distinguished from zero with 95% confidence, was 0.256 nmol.L-1. Steroids and drugs commonly administered with digoxin showed no significant cross-reactivity. In these patients, the positive ratio for determination of DLIS was 46.7% (7 in 15 cases), and its mean serum concentration was 0.55 +/- 0.44 nmol.L-1 (range 0.26-1.52 nmol.L-1). The results were well consistent with that obtained by Dasgupta et al. In conclusion, there are certain increased concentrations of DLIS in the sera of elder patients with cardiac insufficiency, suggesting that digoxin levels measured by immunoassay method must be interpreted carefully in these patients after treatment with digoxin or other digitalis preparations.

Aged↗

PubMed1998

[Establishment of Hymenolepis diminuta-animal model and morphology of cysticercoid].

AIM: To observe the morphological changes in the process of the development of Hymenolepis diminuta. METHODS: The life cycle of Hymenolepis diminuta was established between Rattus domesticus albus and Triboliun castaneum. The morphology of cysticercoid were observed microscopically, and the ultrastructure of the body surface of cysticercoid were observed by scanning electron microscopy. RESULTS: Three phases including the mature stage, the blister stage and the protective outer membrane-forming stage during the growing course of cysticercoid were observed microscopically. Under scanning electron microscope, lots of sieve-like micropores on the surface of mature cysticercoid were seen in the second week after infection. The blister phase was found in the third week and the outer membrane measuring about 45 microns in thickness were found surrounding the cysticercoid and vesicular surface, forming a smooth cyst wall in the fourth week. CONCLUSION: The life cycle of Hymenolepis diminuta has been established in the animal-model. The finding of the three phases during the growing course of cysticercoid is reported for the first time.

Animals↗

PubMed1998

A new species of Anopheles hyrcanus group from Nei Mongol Autonomous Region (Diptera:Culicidae).

Morphology of Anopheles (Anopheles) hailarensis, a new species belonging to the Anopheles hyrcanus group, collected from Hailaer, Nei Mongol Autonomous Region, P. R. of China, is described in adult, pupal, larval and egg stages. It is closely related to Anopheles sinensis Wiedemann, 1828 and Anopheles heiheensis Ma, 1981. Comparisons on adult morphology among above three species and egg morphology between the new species and Anopheles sinensis are made.

Animals↗

PubMed1998

[Comparison of the morphology of wing spot between Anopheles minimus and Anopheles fluviatilis].

AIM: To compare the morphology of wing spot between Anophelesminimus Theobald, 1901 and Anopheles fluviatilis James, 1902 and find out the reliable diagnostic characteristics. METHODS: Anopheles minimus were collected from Jinuo Village, Jinghong County, Yunnan Province. Anopheles fluviatilis were collected from Lingyun County, Guangxi Zhuang Autonomous Region. Measurements of the wing-length and the length of pale and dark spots on the costa and V1 were made with a microscope fitted with an ocular micrometer. RESULTS: A total of 52 females and 60 males of Anopheles minimus and 40 females and 60 males of Anopheles fluviatilis were examined. It was found that the presence of presecutor pale spot and the ratio of sector pale spot to sector dark spot were the important diagnostic morphological characteristics between the above mentioned two species. CONCLUSION: Obvious differentiations exist in the morphology of wing spots between Anopheles minimus and Anopheles fluviatilis.

Animals↗

PubMed1998

[Differentiation of cryptic species A and D of Anopheles dirus complex by polymerase chain reaction].

AIM: To distinguish cryptic species A and D of Anopheles dirus complex using polymerase chain reaction (PCR). METHODS: A diagnostic PCR assay of species was developed by use of three primers, one derived from highly conservative 5.8 S coding sequences and two from different interspecies sequence in the second internal transcribed spacer (ITS2) of ribosomal DNA. RESULTS: Using the PCR method, specific fragments were amplified in both species, the size of fragments is 374 bp for species A and 663 bp for species D. Thirty samples of species A from AFRIMS and HN laboratory colony and seven samples of the species D from Yunnan Province were correctly identified by PCR. Satisfactory results were obtained from the amount of DNA as little as 1/1,600 of extracted DNA of a single mosquito or 1/5 of DNA derived from one leg of a mosquito triturated in water. A total of 148 field-collected specimens of Anopheles dirus from Heping(HP), Baisha(BS), Loukui(LK), and Maoyang (MY) in Hainan Province revealed fragment characteristic of species A, while 30 specimens from Mengla (ML) in Yunnan Province showed the specific fragment of species D. CONCLUSION: A simple and reliable method was developed to identify cryptic species A and D of Anopheles dirus complex and it was further verified that Anopheles dirus from Hainan and Yunnan Provinces is the species A and the species D, respectively.

Animals↗

PubMed1998

[DNA vaccine of Plasmodium falciparum: immune response of BALB/c mice induced by injection of the recombinant plasmid DNA].

AIM: To observe the level of immune responses of BALB/c mice induced by direct injection of the recombinant plasmid DNA and to provide evidence for the application of DNA vaccine of Plasmodium falciparum (P. f.) in animals and humans. METHODS: The recombinant plasmid pcDNA3-Pf8 encoding the hybrid antigens of PfCMR-MSP1(19) was constructed. The presence of Pf8 plasmid was detected in the muscle, liver, kidney, heart, spleen and lung by PCR. ELISA, T lymphocyte transformation test, inhibitory assay of the growth and development of P. f. in vitro were used to determine the level of humoral and Th-cell responses. RESULTS: pcDNA3-Pf8 was amplified by PCR technique in the different tissues from BALB/c mice which were injected with pcDNA3-Pf8. The immune serum was specifically recognized by the soluble antigens of P. falciparum (titer: 1:2,560 by ELISA). The specific proliferative response of spleen T cells from immunized mice was remarkably higher than that of control group, the transformation rate being up to 32.82 +/- 3.64%. The immune serum could also inhibit the growth and development of the erythrocytic stages of P. falciparum in vitro. CONCLUSION: Direct injection with the recombinant plasmid pcDNA3-Pf8 specifically elicits BALB/c mice to generate humoral and cell-mediated immune responses, the resulting immune serum being inhibitory to the growth and development of P. f. in vitro.

Animals↗

PubMed1998

[Cloning and sequencing of the gene coding the sexual stage antigen Pfs48/45 of Plasmodium falciparum].

AIM: To express the antigen Pfs48/45 in vitro and provide an antigen for the development of the transmission-blocking vaccine. METHODS: According to the published nucleotide sequence of Pfs48/45 of Plasmodium falciparum isolate NF54, a pair of oligonucleotides was designed and used as primers(P1, P2). The gene encoding the gametocyte/gamete-specific membrane protein Pfs48/45 of P. falciparum isolate FCC1/HN has been amplified by using polymerase chain reaction (PCR) technique. The PCR product was purified and directly sequenced by the dideoxynucleotide terminator method with 5'-end primer P1. At the same time, the purified PCR product was digested with BamHI and EcoRI and cloned into the plasmid pcDNA3, then the recombinant clones were transformed into E. coli strain TG1. The recombinant plasmid pcDNA3-Pfs48/45 was screened and identified by PCR amplification and restriction analysis. RESULTS: 1. The gene fragment Pfs48/45 was specifically amplified from the genomic DNA of Plasmodium falciparum isolate FCC1/HN; 2. The sequence demonstrated that the that the 5'-end nucleotide and predicted aminoacid sequence of Pfs48/45 from FCC1/HN isolate was basically identical with that from NF54 isolate. We found that the sequence of the Pfs48/45 gene from the isolate FCC1/HN differs from the published sequence(isolate NF54) only at positions 307 and 372(T-->C). The substitution of T-->C at the position of 372 generates a new restriction site Taq I. The PCR product digested by Taq I generates DNA fragment of 984 bp and 379 bp, suggesting that the PCR product is the gene encoding the transmission blocking antigen Pfs48/45; 3. The gene fragment of Pfs48/45 was directly inserted into the BamHI and EcoRI site of plasmid pcDNA3. CONCLUSION: The nucleotide sequence of Pfs48/45 of Plasmodium falciparum isolate FCC1/HN from south China was similar to that of isolate NF54. The recombinant plasmid pcDNA3-Pfs48/45 was successfully constructed, providing a means to evaluate the role and biological function of this sexual-stage-specific protein of Pfs48/45.

Amino Acid Sequence↗

PubMed1998

[Ultrastructural differences of RMV and TMV infected Nicotiana tabacum mesophyll cells for distinguishing virus strains].

Nine strains of ribgrass mosaic virus (RMV) and tobacco mosaic virus(TMV) from cruciferous and solanaceous plants in different geographic regions of China were used to inoculate 4-leave-old plants of Nicotiana tobacum for observation of ultrastructually pathological changes due to infection of different strains. The samples of the mesophyll cells of the plants 15 d after inoculation were prepared in a routine and examined using transmission electronic microscopy. Characteristic virion arrangement, inclusion forms, and cell structural aberrations were found different among the various strains. The virions were accumulated in cluster, arranged in ring scattered, irregularly congregated with membrane, and aggregated in angle layer or parallel layer in cytoplasm and vacuoles whereas they were not found in organelles including nuclei, chloroplasts, and mitochondria. The inclusions with bacilliform, club-shaped or granulous X-tubule varied in number and form among the viral strains investigated. The abnormality of cell wall including thickening, collapsing and distortions were also observed among the cells infected by the strains. Other distinguishable changes attributed to the strains included the number, size, shape, and clumping pattern of chloroplasts, and of starch grains and osmiphilic globules chroloplasts of mesophyll cells infected only by two of the 9 strains examined. Additionally, the increased numbers of mitochondria and endoplasmic reticulum were observed in the cells infected by some of the strains. The results indicate that the ultrastructural changes due to viral infection may be useful for distinguishing various RMV and TMV strains.

Microscopy, Electron↗

PubMed1998

[Ultrastructures of a mycoplasma-like organism causing mulberry dwarf disease].

The pathogen causing the dwarf disease of mulberry in Tongxiang, Zhejiang Province was investigated based on transmission electronic microscopy of the leaf vein of diseased plants collected in the field. A mycoplasma-like organism was identified in the sieve tube, companion, and parenchyma cells of the phloem tissues infected. The organism was spheric or oval in shape, ranging from 50 nm to 160 nm in diameter, and with bilamina unit membrane of 8-10 nm in thickness, and was filled with nuclear strands or fibrous material. Some nuclei of mesophyll cells in the diseased leaves were found disrupted as their nuclear membrane was broken, followed by of nucleo-cytoplasmic matrix and dispersive disappearance of nucleoli. Furthermore, other ultrastructural aberration including depletion of chloroplast stroma, disruption of chloroplast grana, increase of mitochondria and rough endoplasmic reticulum, and discomposition of some mitochondrial cristae were also observed associated with the pathological changes caused by the mycoplasma-like organism. In contrast, this type of organism was not found in healthy plants examined. Thus, the mycoplasma-like organism is likely to be a pathogen attributable to the mulberry dwarf disease.

Microscopy, Electron↗