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Biomedical subjects

X He

Publications and source records attributed to X He.

At least 181 records · Page 10Linked to original sources
PubMed2000

[The studies on the molecular mechanism of rifampin-resistant Mycobacterium tuberculosis].

OBJECTIVE: To evaluate the molecular mechanism of rifampin (RFP)-resistance of M. tuberculosis, and to provide evidence of molecular genetics for basic and clinical research of tuberculosis. METHODS: rpoB gene mutation of M. tuberculosis was detected with PCR-SSCP from 262 clinical isolates, including 74 drug sensitive strains, and 188 RFP-resistant only or multiple drug-resistant strains of M. tuberculosis, collecting from Henan, Hebei and Anhui province, Beijing and Shanghai cities. Plasmids were extracted from 76 clinical isolates of M. tuberculosis with alkaline bacteriolytic methods. RESULTS: Mean mutation rate of rpoB gene was 92% in the RFP-resistant clinical isolates of M. tuberculosis. Respectively, the mutation rate was 90.0% in Henan province, 94% in Hebei province, 91% in Anhui province, 91% in Beijing city and 92% in Shanghai city. There was no significant difference between results from the provinces and the cities (chi 2 = 0.42, P > 0.05). However, mutation of rpoB gene was not detected in 74 sensitive clinical isolates of M. tuberculosis. Moreover, in 76 clinical isolates of M. tuberculosis the plasmids were not found, including 29 sensitive strains, 33 RFP-resistant only or multiple drug-resistant strains and 14 RFP, isoniazid, streptomycin and ethambutol-resistant clinical isolates. CONCLUSIONS: This study confirmed the strong correlation between the RFP-resistance and the mutation of the rpoB gene, which might be a major molecular mechanism of RFP-resistance in M. tuberculosis. No evidence shows that M. tuberculosis has the plasmid, which mediates RFP resistance to M. tuberculosis.

Antibiotics, Antitubercular↗
PubMed2000

[Delayed type hypersensitivity responses to recombinant mycobacterial antigen 38,000 in guinea pigs sensitized to Mycobacterium tuberculosis].

OBJECTIVE: To evaluate the ability and influencing factors that recombinant 38,000 antigen induces delayed-type hypersensitivity(DTH) reaction in guinea pigs. METHODS: In one skin test, physiological saline as negative control and PPD as positive control, guinea pigs were shaved on the back and given intracutaneous injection with 0.1 microgram, 0.2 microgram, 0.4 microgram of recombinant 38,000 antigen. Skin reactions were measured 48 h after antigen injection, each measuring two transverse diameters of the induration. In the other skin test, each guinea pig was intracutaneously injected in four sites, respectively with 5 IU PPD and recombinant 38,000 antigen (0.1 microgram, 0.2 microgram and 0.4 microgram) or 5 IU PPD and biantigen(combination 38,000 with 16,000 antigen, 0.1 microgram, 0.2 microgram and 0.4 microgram). Single antigen and biantigen were tested in three separate experiments. Each experiment needs six sensitized guinea pigs. Skin reactions were measured 24 h, 48 h and 72 h after antigen injection. RESULTS: DTH responses induced by 0.4 microgram were weaker than 0.1 microgram and 0.2 microgram in 24 h. 0.1 microgram and 0.2 microgram elicited DTH responses similar in strength to that of 5 IU PPD. From 0.1 to 0.4 microgram, similar dose of recombinant 38,000 antigen and combination antigen elicited similar DTH responses. DTH responses induced by recombinant 38,000 antigen had better be measured at 48 h, however that induced by combination antigen at 24 h. CONCLUSIONS: Recombinant 38,000 antigen can induce DTH responses in guinea pigs. Dose of antigen is important factor that affect DTH responses in guinea pigs.

Animals↗
PubMed2000

[Prevalence of cag A and vac A subtypes of Helicobacter pylori in Guangzhou].

OBJECTIVE: To investigate the prevalence of cytotoxin associated gene (cag A) and vacuolating cytotoxin gene (vac A) subtypes of Helicobacter pylori (Hp) from patients with upper gastrointestinal diseases in Guangzhou, and to assess the relationship between cag A, vac A subtypes and Hp related gastrointestinal diseases. METHODS: 191 Hp strains were isolated from patients with different gastrointestinal diseases in Guangzhou. Bacterial DNA from all these strains was extracted. cag A and vac A alleles were typed using PCR with specific primers. RESULTS: In Guangzhou, Hp cag A positive rate was 85.3% (163/191). cag A positive rate was significantly higher in gastric cancer and peptic ulcer than that in chronic gastritis (P < 0.05). There were six vac A mosaicisms, including 168 for s1a/m2 (88.0%), 14 for s1a/m1b (7.3%), 6 for s1b/m2 (3.1%), 1 for s1b/m1b (0.5%), 1 for s2/m2 (0.5%) and 1 for s1a/m1b-m2 (0.5%). The rate of vac A s1a/m2 subtype in chronic gastritis, peptic ulcer and gastric carcinomas was 87.5% (70/80), 87.5% (84/96) and 93.3% (14/15) respectively. There was no significant relationship between cag A and vac A subtypes (P > 0.05). CONCLUSION: cag A(+) and vac A s1a/m2 subtype of Hp is predominant in patients with upper gastrointestinal diseases in Guangzhou, cag A(+) strains are further more common in patients with gastric cancer and peptic ulcer.

Adolescent↗
PubMed2000

[A clinical investigation on cataract surgery with 2.8 mm incision].

OBJECTIVE: The results of phacoemulsification which was performed through a 2.8 mm clear cornea tunnel incision and foldable intraocular lens (IOL) implantation were analyzed. METHODS: On 126 eyes with cataract of 105 cases, phacoemulsification with foldable IOL implantation was randomly performed. The results of postoperative vision, refraction, corneal edema, anterior chamber flare and the rate of corneal endothelial cell loss were retrospectively summarized. RESULTS: The uncorrected visual acuities of postoperative 1 day, 3 days, 1 week, 2 - 3 months, >or= 0.5 were in 102 eyes (81.0%), 108 eyes (85.7%), 112 eyes (88.9%) and 112 eyes (88.9%), respectively. The mean diopters of astigmatism at postoperative 3 days, 1 week, 1 month and 3 months were (1.09 +/- 0.51) D, (1.02 +/- 0.47) D, (0.88 +/- 0.52) D and (0.81 +/- 0.62) D, respectively. The mean diopters of astigmatism at postoperative 1 week, 1 month and 3 months compared with that before the surgery had no significant difference (P > 0.05). The comparison between the preoperative astigmatism and that at postoperative 3 months showed that only about 0.08D of change existed. The postoperative corneal edema and anterior chamber flare were mild, the anterior chamber configuration remained well, and the rate of endothelial cell loss was 11.9%. CONCLUSIONS: The surgical incision is small and easy to perform. Postoperatively, the reaction is mild, the change of astigmatism is small in degree, the best visual acuity can be obtained at the early stage and the refractive status is stable, thus the duration for restoration is greatly shortened.

Adolescent↗
PubMed2000

[Studies on Legionella-contamination to the air-conditioning cooling towers in big hotels and on its seroprevalence in the related populations in Beijing].

OBJECTIVE: To understand the situation of Legionella-contamination at cooling towers of big hotel and the level of Legionella-infection among related populations in Beijing. METHODS: Thirty-eight cooling towers of hotels were chosen for detection of Legionella. Four hundred and fourteen staff members from the hotels were selected as exposure group, with another 414 from general population as controls, for the detection of Legionella antibodies. RESULTS: Sixteen strains of Legionella pneumophila (Lp) were isolated from 21 of the 38 cooling towers, and the predominant strain was Lp serum group 1 (50%, 8/16). The seroprevalence of Lp antibodies for the exposure group was 9.9% (41/414), comparing to 3.5% (14/414) from the control group. The difference was statistically significant (chi(2) = 14.2, P < 0.01). CONCLUSION: Legionella was discovered in air-conditioning cooling tower of the hotels, which threatened the health to the population exposed to it.

Air Conditioning↗
PubMed2000

[Factor XIIa-inhibited diluted thromboplastin time can reflect coagulation process].

OBJECTIVE: To establish a screening test that can reflect two stages of coagulation process. METHODS: With FXII a being blocked, the effects of various dilution of thromboplastin on clotting time were observed. FX a activity was determined by chromogenic assay. RESULTS: (1) At high concentration of thromboplastin, FXII a-inhibited diluted thromboplastin time (FXII ai DTT) of pooled normal plasma and FXI deficient plasma was very similar, but at low concentration, FXII ai DTT was in order of FVIII and FIX deficient plasma > FXI deficient plasma > pooled normal plasma. (2) FXI consumption by immunologic method induced FXII ai DTT of pooled normal plasma prolonged, and addition of FXI to FXI deficient plasma shortened FXII ai DTT. (3) Alpha-thrombin blocked by hirudin at different time (10 - 80 seconds) resulted in decreased FXa generation, and the earlier the block, the more the decrease. Under the same condition, the amount of FXa generation was in order of platelet-rich plasma > platelet-poor plasma > FXI deficient plasma. CONCLUSION: (1) Our data support the two-stage hypothesis and confirm the important role of FXI in the amplification stage. (2) FXII ai DTT as a screening test for coagulation process may be practicable.

Blood Coagulation↗
PubMed2000

[In vitro induction of autologous T cell killing by heat treated human chronic myelogenous leukemia cells].

OBJECTIVE: To investigate the potential of autologous T cell killing of heat treated chronic myelogenous leukemia (CML) cells (autologous tumor killing, ATK). METHODS: (51)Cr release assay was used to measure the ATK activity of autologous T cells against CML cells treated with 42 degrees C for 30 minutes (heat) or 37 degrees C for 30 minutes (non-heat). The phenotypes of T cells and heat shock protein 70 (HSP70) expression of CML cells were measured by flow cytometry (FCM). T cells from the CML patients were stimulated and expanded by autologous mixed lymphocyte/tumor cell cultures (MLTC). RESULTS: ATK activity of autologous T cells to the non-heated and heated CML cells were found in 4 (19.05%) and 10 (47.62%) of the 21 cases, respectively. The ATK activity of interleukin-2 (IL-2) stimulated autologous T cells against heated CML cells was markedly higher than that of unstimulated autologous T cells against non-heated CML cells (P < 0.001). FCM analysis showed that no HSP70 was expressed on the CML cell membranes whether heated or non-heated, but intracellular HSP70 expressions were (83.42 +/- 5.65)% and (78.34 +/- 6.32)% pre- and post-heated, respectively. The phenotypes of T cells stimulated and expanded in MLTC were TCRgammadelta - CD(3)(+), mostly CD(8)(+), with some activation markers (CD(25) and HLA-DR) expression. The ATK activities of these T cells against the heated and non-heated CML cells and K562 cells were (51.25 +/- 4.26)%, (36.52 +/- 3.83)% and (2.92 +/- 1.19)%, respectively. CONCLUSIONS: ATK activity of autologous T cells against CML cells could be induced or enhanced by heat treatment of the CML cells particularly of T cells stimulated with IL-2. This ATK activity was not associated with gammadelta T cells or HSP70 expression of CML cells.

Adolescent↗
PubMed2000

[Distinguish of the original fungi of the Chinese traditional medicine, hongqu with gas chromatography fuzzy clustering analytical method].

OBJECTIVE: To establish a gas chromatography fuzzy clustering analytical method for classifying of origin fungi of the Chinese traditional medicine, Hongqu. METHODS: The volatile and nonvolatile components of 7 ordinary species of Monascus including M. aurantiacus Lee, etc. were analyzed by capillary gas chromatog raphy using FID: Inlet temperature 280 degrees C, detector temperature 280 degrees C, temperature program 130 degrees C, 5 min-->10 degrees C.min-1-->200 degrees C, 10 min. RESULTS: In the peak number and contents of volatile and nonvolatile components of Monascus exist obviously differences through which Monascus can be distinguished easily by the main fingerprint peaks within 20 minutes. CONCLUSION: The capillary gas chromatography fuzzy clustering analytical method is useful to the identification of Monascus fungi.

Chromatography, Gas↗
PubMed2000

[Studies on application for classification and identification in Mycobacterium by analysis of PCR amplification of 16S-23S ribosomal DNA spacer sequences].

The 16S-23S ribosomal DNA spacer sequence of mycobacterium were amplified by PCR. The products were visualized by PAGE, and evaluate the possibility for classification and identification of mycobacterium at gene level. The sensitivity of PCR in annealing temperature 45 degrees C was 500 fg/microL, whereas 50 degrees C was 5 pg/microL. The results showed that: the amplified bands ranging from 300 to 600 bp, most of rapid-growing Mycobacterium and Nonmycobacterium tested have more bands and the bands molecular weights were larger than slow-growing Mycobacterium. The relativity of mycobacterium < 70%, most of them < 50%. This experimental method might be rapid and effective for differentiation of Mycobacterium at species level.

Cluster Analysis↗
PubMed2000

[Cloning and expression of metallothionein gene of Bombyx mori].

Yeast MTI gene from vector pCMI-1 was used as a probe. It appeared strong hybridization signals when the total DNA of Bombyx mori Huishu eggs hybridizes with the probe. The 1-6 kb DNA fragments were isolated from the EcoR I digested total DNA of Bombyx mori Huishu eggs and ligated with M13- vector digested by restriction EcoR I. The ligation mixtures were used to transform E. coli DH5 alpha. blue/White colonies selection was used to identify colonies with insert. Approximately 4000 white colonies were selected, so the part genomic library of Bombyx mori was constructed. Three positive colonies were gained from the genomic library by southern blotting analysis, designated T1 (pZHC-1), T5 (pZHC-5), T7 (pZHC-7). Digesting the recombinant plasmid pZHC-5 with 12 restriction enzymes, the results suggested that the inserted fragment was about 1.2 kb and there was only a Hind III site. The experiment of resistant to CuSO4 proved that the DH5 alpha cells contain recombinant plasmids were more resistance than the recepient DH5 alpha cells. According to these results, the inserted fragment possibly contains the gene encoding Metallothionein of Bombyx mori. The sequence analysis of the inserted fragment and its high-expressions in E. coli are in progress.

Animals↗
PubMed2000

[Study on extraction process for psoralen in compound prescription by orthogonal design].

The study on water volume, extraction time and times for the extraction of psoralen in compound prescription Yiniao Tong capsule has been carried out by orthogonal design. The process condition has been determinated, extracting prescription herbs with water for 3 times(2 hour and 16 time amount of water all told). The determination method used in this experiment was TLC-scanning.

Capsules↗
PubMed2000

[Neurofibromatosis type 2].

OBJECTIVE: To investigate the clinical characteristics and management strategies of bilateral acoustic neuromas. METHODS: The data of 7 patients with bilateral acoustic neuromas collected between 1990 to 1998 were retrospectively analyzed. RESULTS: Altogether 122 patients with acoustic tumors were treated from 1990 to 1998, in which 7 cases (5.8%, 6 male and 1 female) had bilateral acoustic neuromas. The age at onset of symptoms ranged from 13 to 60 years (average 29.1 years). Progressive hearing loss and tinnitus were the initial symptoms in 4 cases. Either strabismus, ptosis, headache or dysequilibrium was presented in 4 cases. Six cases complicated tumors in the central nervous system and/or other sites. Five cases had cafe au lait spots. One case had posterior subcapsular lenticular opacity. Four cases fell into severe (Wishart) type and 2 into mild (Gardner) type. The tumors were unilaterally removed in 4 patients through the retrolabyrinthine approach (1 case) or the retrosigmoid approach (3 cases). In these 4 patients, one died of central respiratory failure after the operation; two had contralateral tumor removal through retrosigmoid approach 3 weeks after the first surgery. One of the patients died of encephaledema after the surgery. No hearing impairment and facial nerve paralysis occurred in one case operated on through the retrolabyrinthine approach, whereas in those through retrosigmoid approach, 4 ears had hearing loss and 3 sides had facial nerve paralysis. CONCLUSION: The clinical characteristics and treatment strategies for bilateral acoustic neuromas are different from those of unilateral acoustic neuroma. Individualization of management is a prerequisite for the success of the treatment. To avoid injury to the VII and VIII cranial nerves, monitoring the nerve functions during the surgery is important.

Adolescent↗
PubMed2000

Congenital choledochal cyst--report of 56 cases.

OBJECTIVE: The aim of this paper is to describe the mechanism, clinical manifestation, diagnosis and surgical management of congenital choledochal cyst. METHODS: From 1984 to 1997, 56 cases of congenital choledochal cyst were reviewed. Among them, 8 patients were male, 48 patients were female, the age ranges from 12 to 50 years old with an average of 26.3. RESULTS: The main clinical manifestation includes jaundice, abdominal pain and abdominal mass. All of them were confirmed by ultrasonography, while 39 cases were performed ERCP and PTC with the same diagnosis. Fifty-one patients were performed cystectomy and hepatojejunostomy, two cases were performed cystjejunostomy because of diffused angioma and severe hemorrhage respectively, external drainage was performed in one case with emergent cholangitis, the other two cases were reported malignancy through biopsy and operation was abandoned. CONCLUSIONS: Ultrasound diagnostics is essential to accurately diagnose the cyst, preoperative ERCP is helpful for differentiating pancreatic duct from bile duct, while MRCP is a reliable method; cystectomy and cholangiojejunostomy is recommended, laparoscopic procedure is becoming more and more accepted.

Adolescent↗
PubMed2000

[Prevention and management of complications with laparoscopy cholecystectomy].

OBJECTIVE: To prevent the complication of laparoscopy cholecystectomy (LC). METHODS: This text analysed 1,200 cases retrospectively with LC from Feb. 1993 to May. 1998. RESULTS: Three cases with biliferous duct injury, two cases with bile leakage from the stamp of cystic duct, two cases with gallbladder artery injury. CONCLUSIONS: Strict preoperative examination and standard operative procedure can reduce markedly complication of LC.

Bile Ducts↗
PubMed2000

The bi-directional regulation of filamin on the ATPase activity of smooth muscle myosin.

OBJECTIVE: The aim of this study is to investigate the functional relationship between filamin, a known actin binding protein, and myosin and the effects of filamin on the interaction between myosin and actin. METHODS: Ultra-centrifugation method was used to investigate the binding of filamin to both phosphorylated and unphosphorylated myosins. Mg-ATPase activities of both phosphorylated and unphosphorylated myosins in the presence and absence of actin were measured to observe the effects resulted from filamin-actin and filamin-myosin interactions. RESULTS: It was found that filamin is also a myosin binding protein. Filamin inhibited the actin activated Mg-ATPase activity of phosphorylated myosin and stimulated Mg-ATPase of phosphorylated myosin in the absence of actin; in addition, filamin stimulated Mg-ATPase activity of unphosphorylated myosin in both the presence or absence of actin. CONCLUSION: The result suggest that the effects of filamin on the myosin Mg-ATPase activities are bi-directional, i.e., stimulatory via binding to myosin and inhibitory via binding to actin.

Actins↗
PubMed2000

Diagnosis and treatment of insidious recurrent small intestinal hemorrhage.

OBJECTIVE: To improve the localized diagnosis of insidious recurrent small intestinal hemorrhage. METHODS: This retrospective analysis include 64 cases of such diseases, which were admitted from 1988 to 1998 to our hospital. RESULT: Ultrasonography, CT, small bowel pneumobariumgraphy, diluted barium enema, isotopic examination, DSA and intraoperative small-bowel endoscopy were used for diagnosis of hemorrhagic site, and 37 cases got a definite location before operation, while 10 cases were confined the diagnosis during the operation. Forty-seven cases were treated surgically, while the other 17 cases had non-surgical treatment. Of the 47 cases, 39 cases underwent partial enterectomy, 5 cases had suture and ligature of vascular deformity, 2 cases had Whipple's operation, and one patient had ectomy of the end of ileum and right colon. CONCLUSION: DSA, Isotopic examination and intraoperative enteroscopy are of considerable importance for the location judgement of recurrent small intestinal hemorrhage.

Adolescent↗
PubMed2000

[Study on the photoinduced-color changing about novel azobenzocrown ether derivatives 16ABC-OH and 16ABC-NH2 in water solution and Langmuir-Blodgett film].

Two kinds of azobenzocrown ether derivation 16ABC-OH and 16ABC-NH2 have been synthesized, and their photoinduced color changing phenomena has been investigated in water solution, the reaction of 16ABC-OH is the photochemical Cis-trans-isomerization, and it is a first-order reaction, but the reaction of 16ABC-NH2 photochemical Cis-trans-isomeriation is very complex; and it is not a first-order reaction. In Langmuir-Blodgett film of 16ABC-OH, there is not molecular self-assembly phenomenon, the part of Cis-16ABC-OH become to iso-16ABC-NH2, but in the film, 16ABC-NH2 form H-Polymer by self-assembly, and the photochromic Cis-trans-isomerization is forbidded.

English Abstract↗