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Biomedical subjects

J G Xu

Publications and source records attributed to J G Xu.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Serological investigation on Yang Xiao-xia's "mysterious disease"].

The famous "mysterious disease" of Yang Xiao-xia, a girl from Shangdong Province, was diagnosed as multi-bacterial synergistic gangrene based on bacteriological, serological and antibiotics sensitivity findings. In order to uncover the initial pathogenic bacteria and to investigate their relationship with environment, a total number of 18 serum samples were collected from volunteers living around patient's home and from patient's relatives. Serological study on 4 bacterial strains isolated from patient, named as Eubacterim lentum, Stereptococcus acidominimus, Y6 and Yp was conducted with Western blot, using whole cell protein preparation was carried out, and data obtained was statistically analysed. Our findings indicated that YP and Y6 strains were interrelated with environment of patient's home and Y6 from the pool where patient visited often and several hours before she intially experienced the disease. The strains of Y6 and YP are virulent to animials, indicating that they serve as potential pathogens. Eubacteriumlentum and Streptococcus acidominimus are irrelevant to environment.

Bacterial Infections↗
PubMed1996

Adherence patterns and DNA probe types of Escherichia coli isolated from diarrheal patients in China.

One hundred and seventy-two strains of Escherichia coli isolated from diarrheal patients in Beijing, P.R. China, were analyzed for plasmid DNA profile, HEp-2 cell adherence ability and reactivity to 10 previously described DNA probes. They had not been recognized as pathogenic E. coli in China. Of the 110 strains tested, 76 (69%) contained one or multiple large plasmids. Of the 71 strains with the large plasmids 64 could adhere to HEp-2 cells. Of the 172 strains, 102 (59.3%) were hybridized with at least one of the 10 probes. Of those, seven strains hybridized with enteroaggregative E. coli (EAggEC) probe. Their serotypes were O128 (two strains), O6 (one strain), and O111 (one strain). Three strains were untypable. Six and three strains were hybridized with enteropathogenic E. coli (EPEC) attaching and effacing genes (eae) or EPEC adherence factor (EAF) probe, respectively. Two non-O157: H7 strains hybridized with enterohemorrhagic E. coli (EHEC) probe. Seventy-two strains (41.9%) hybridized with shiga-like toxin 2 or 1 (SLT2 or SLT1) probes. Among the SLT1 or SLT2 probe-positive strains, 54 hybridized with invasive (INV) plasmid probe developed for identification of enteroinvasive E. coli (EIEC) and Shigella species. The INV and SLT probe-positive strains might represent a new variety of verotoxin-producing E. coli (VTEC).

Animals↗
PubMed1995

Simultaneous expression of CFA/I and CS3 colonization factor antigens of enterotoxigenic Escherichia coli by delta aroC, delta aroD Salmonella typhi vaccine strain CVD 908.

Among the known colonization factors of enterotoxigenic Escherichia coli (ETEC), CFA/I and CS3 (the common antigen in the CFA/II family of fimbrial antigens) are two of the most prevalent fimbrial antigens found in clinical isolates but are never expressed by the same wild-type strain. We manipulated the genetic determinants encoding CS3 and CFA/I fimbriae so that these two important colonization factors are expressed simultaneously in attenuated Salmonella typhi live oral vaccine strain CVD 908, including after growth in liquid medium (CFA/I is poorly expressed by wild-type ETEC in broth culture). The recombinant fimbrial structures produced by CVD 908 are morphologically indistinguishable from the CS3 fibrillae and CFA/I rod-like fimbriae produced by ETEC, and are recognized by monospecific CS3 and CFA/I antibodies. This prototype construct may prove useful in investigating the live vector approach to immunoprophylaxis of ETEC diarrheal disease.

Antigens, Bacterial↗
PubMed1994

[Study of mechanism of selective head cooling-dehydration combined therapy for brain resuscitation: effect on function of brain cellular membrane].

We induced cerebral complete ischemia (CCI) by "four-vessel" model. The changes of Na+,K(+)-ATPase, Ca2+, Mg(2+)-ATPase, phospholipase A2 (PLA2), total phospholipids on brain cellular membrane (BCM) at 30, 180, 360 min of reperfusion following 30 min CCI were observed. The effects of selective head cooling (SHC, 28C, surface cooling method), mannitol dehydration (MD), and selective head cooling-dehydration combined therapy (SHCDCT) on these changes were also investigated. Compared with non-ischemic, during reperfusion activities of Na+, K(+)-ATPase, Ca2+, Mg(2+)-ATPase decreased while PLA2 increased (P < 0.001), phospholipids decreased at 180 and 360 min of reperfusion (P < 0.01). SHC and SHCDCT blocked all above changes, MD had no effect. These results suggest that SHCDCT after starting reperfusion do promote recruitment of BCM function by blockade of the successive reperfusion damage on BCM.

Animals↗
PubMed1994

[Studies on the anticonvulsive activity of pyrazolidinones].

The anticonvulsive activity of three kinds of pyrazolidinones: 5-benzyl-substituted-3-pyrazolidinones; 5-benzyl-1-alkyl substituted and 1-alkyl substituted-3-pyrazolidinones were studied. Fourteen substitutes of these three kinds of pyrazolidinones were found to be potent anticonvulsants. In doses less than TD50, they were found to be able to protect mice and rats from seizures produced by maximal electroshock seizure (MES), such action appeared rapidly and lasted for a short period. II-f was shown to be the most potent anti-MES agent among these three kinds of pyrazolidinones. It also showed therapeutic effect in treating experimental epilepsy produced by intrahippocampal injection of zinc sulfate in rabbits and audiogenic seizures in rats. The third kind of pyrazolidinones also showed anti-metrazol induced seizures in mice.

Acoustic Stimulation↗
PubMed1994

Entrapment of posterior interosseous nerve of forearm. Report of 25 cases.

Of the 25 cases of entrapment, or compression syndrome of the posterior interosseous nerve of the forearm reported, 23 were treated surgically. The compressing or entrapping factors found during the operations consisted of 14 sites in tendinous tissues, 12 in vessels, 6 in scar adhesions, and 3 unclear. Of 11 cases each had 2 or more compression sites. 19 patients underwent local decompression. And 4 cases had membranous and degenerated nerves resection and end-to-end anastomoses. Hypertrophy and inflammation appeared to be the main pathological changes in 10 cases. The causes and pathology are discussed and the early diagnosis and treatment emphasized.

Adolescent↗
PubMed1992

[Synchronous spectrofluorimetry for simultaneous determination of riboflavin and pyridoxine and its application in multivitamin preparations].

A new method for the simultaneous determination of riboflavin and pyridoxine by synchronous spectrofluorimetry is described. The measurement was carried out in a buffer solution of pH 7 with delta lambda = 58 nm for synchronous scanning. Under the experimental conditions two peaks appeared at 526 nm and 389 nm in the obtained synchronous fluorescence spectrum, corresponding to riboflavin and pyridoxine, respectively. This method was proved to be simple and specific. The fluorescence relative intensity is linearly related with concentration over the range of 0-1 microgram/ml and 0-1.5 micrograms/ml for riboflavin and pyridoxine, respectively. The detection limit was 0.5 ng/ml for riboflavin and 1 ng/ml for pyridoxine. The relative errors of the measurements were less than 5% for artificial samples. The proposed method has been applied to the analyses of riboflavin and pyridoxine in three kinds of commercial multivitamin preparations. The obtained synchronous spectra of multivitamin preparations coincided with those of the mixed standard solution of riboflavin and pyridoxine. Recoveries of 93.5-105.7% were obtained.

Drug Combinations↗
PubMed1991

Experimental infection of specific-pathogen-free mice with enterohemorrhagic Escherichia coli O157:H7.

By subcutaneous inoculation of 10(8) CFU of enterohemorrhagic E. coli O157:H7, specific-pathogen-free mice revealed most of the symptoms and histological changes observed in patients. The histological changes in intestine were mainly seen in the distal parts of small intestine and the cecum. Vacuolation of villi in the cecum was also observed. The histological changes in the kidneys of the infected mice were featured as the swollen epithelial cells of glomeruli and the marked thickening of glomerular capillaries with barely visible lumens. Unexpected findings in the bronchiole were characterized by sloughing of the epithelial cells of bronchiolar wall, leading to partial or complete obstruction of the lumens. Histological changes in the spleen, liver and lymphnodes were also observed. The bacteria were recovered from the feces, contents of small intestine, and samples taken from kidney, liver, heart, spleen, different parts of small intestine, cecum, and colon. By using peroxidase-antiperoxidase (PAP) assay with polyclonal antibodies against "O" antigen of E. coli O157:H7, it was observed that the samples taken from the brain, kidney, ileum, cecum, spleen, and liver gave positive reactions. Feces and contents of small intestine obtained from all of the infected animals were positive by occult blood test. These results show that the experimental infection of E. coli O157:H7 in this model is systemic in nature.

Animals↗
PubMed1990

Virological survey of rhesus monkeys in China.

A virological survey of rhesus monkeys captured in China for 13 viruses and/or antibodies was performed. Antigens used were SFV, SF40, HSV-1, Sa11, measles, vaccinia, epidemic or simian hemorrhagic fever, Langat, Kunming, poliomyelitis, HIV, SV41 and rubella. Monkeys were from Sichuan, Hunan, Guizhou, Yunnan and Guangxi provinces. Antibody was detected to all the listed viruses except HIV, SV41 and rubella. Both SFV and SV40 were recovered from monkeys, but H. simiae, LCM and coxsackieviruses were not.

Animals↗
PubMed1990

[Plasmid DNA transformation of Yersinia pseudotuberculosis by electroporation].

Rendering cells permeable to DNA molecules, electroporation involves the application of high intensity electric fields of short duration to reversibly change the biomembranes, which has been used successfully in some species of both gram negative and positive bacteria. We first reported the electro-transformation technics of Yersinia pseudotuberculosis. The plasmid pJGX20 was constructed by cloning the 9.5 kb plasmid encoding pesticin into Pst I site of pBR328. Transformation efficiency of 103 transformants/micrograms DNA was obtained at voltage of 1300V or 1400V, capacity of 25 microF, time constant of 48-52 msec, with 10% glycerol as electroporation buffer. The pesticin gene of pJGX20 was expressed well in Y. pseudotuberculosis.

DNA, Bacterial↗
PubMed1989

[Studies on synthetic new drug SC1001-sodium against epilepsy induced by coriaria lactone in rabbits].

In the present experiment, SC1001Na synthesized by West China University of Medical Sciences was used for studying to resist epilepsy induced by coriaria lactone. Forty-two normal male rabbits weighing 1.7-2.5 kg were randomly divided into four groups. The animals of the control group received coriaria lactone (3 mg/kg, i.m.). The animals in each of the experimental groups were injected separately with SC1001Na (100, 200 and 300 mg/kg, i.p.), but the control animals were not injected with SC1001Na. Thirty minutes later, the animals of the experimental groups were injected with the same dose of coriaria lactone as the control animals. The behavior of all animals before and after injection were observed continuously in 4-5 hours. The ECoG of eight animals of them were observed at the same time with telemetric method. The results of experiments indicated that SC1001Na is effective on epilepsy induced by coriaria lactone, in decreasing seizure rate, lengthening latent period, reducing seizure degree, as well as in decreasing mortality.

Animals↗
PubMed1989

[Investigation on calcifications in the breast].

This article reported the result of analysis of 96 cases with heaps of calcifications in the breast all verified by operation. The calcifications, according to the appearances on X-ray film were classified into 4 patterns: club-shaped, fine sandy, fragmented stonelike and coalescent. A comprehensive analysis was made in regard to spatial distribution and amount of calcification and the presence of a mass. The results indicated that club-shaped calcification is highly suggestive of malignancy regardless of the amount of calcification and the presence or absence of a mass. Simple fine sandy calcification in the absence of a mass can not differentiate benign from malignancy because of wide range of overlapping, whereas simple fragmented stone and coalescent types, according to the authors opinion denote benign.

Adenofibroma↗
PubMed1989

[Effects of synthetic new drug SC1001-sodium on respiratory frequency, heart rate, rectal temperature and electrocorticogram in rabbits].

Seventeen normal male rabbits weighing 1.7-2.8 kg were randomly divided into 2 groups. The experimental group (ten rabbits) was injected with SC1001Na (200 mg/kg, i.p.). The control group (seven rabbits) was injected with normal saline of the same volume. Continuous observations for 6 hours were made after injection, with reference to respiratory frequency (RF), heart rate (HR), rectal temperature (RT) and ECoG of these rabbits. The results of experiments indicate that SC1001Na has a slight inhibitory effect on RF and RT, an obvious inhibitory effect on the activity of central nervous system, and an accelerating effect on HR in rabbits.

Animals↗
PubMed1987

A DNA probe to identify enterohemorrhagic Escherichia coli of O157:H7 and other serotypes that cause hemorrhagic colitis and hemolytic uremic syndrome.

Enterohemorrhagic Escherichia coli (EHEC) cause hemorrhagic colitis and hemolytic uremic syndrome (HUS), make potent cytotoxins (Verotoxins [VT] or Shiga-like toxins), and possess a plasmid (approximately 60 megadaltons) that encodes a new fimbrial antigen and promotes attachment to epithelial cells. We evaluated the use of a DNA probe, prepared from a 3.4-kilobase segment of the EHEC plasmid, to detect EHEC. The probe hybridized with 106 (99%) of 107 O157:H7 and 34 (77%) of 44 O26:H11, VT-positive strains from patients with colitis, HUS, and diarrheal disease and hybridized with 21 (81%) of 26 VT-positive E. coli of serotypes other than O157:H7 or O26:H11 from patients with hemorrhagic colitis and HUS. We examined 601 other strains, including 18 serotype O26 isolates of H types other than H11, 306 enteropathogenic E. coli, 60 enteroinvasive E. coli, 119 enterotoxigenic E. coli, and 20 isolates from the urinary tract and 77 isolates from the normal intestinal flora; only one (O127:H-) was positive (specificity, 99.8%). Serotype O26:H11, previously considered a classic enteropathogenic E. coli serotype, is now shown to be EHEC.

Child↗