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Biomedical subjects

J Xu

Publications and source records attributed to J Xu.

At least 1,117 records · Page 62Linked to original sources
PubMed1994

Characteristics of acupuncture meridians and acupoints in animals.

In recent years, an increasing number of studies has been conducted on the biophysical characteristics of the meridians and acupoints in humans and animals. The authors aim to further illustrate the objective existence and superficial locations of the meridians in various species of animals. Twelve sheep, ten goats, thirteen pigs, eleven cats, eight rabbits and seven donkeys were used to measure low impedance lines (LILs) and high percussion sound lines (HPSLs) on the skin surface of the animals, along the vertical planes of the dorsal line, using electrical impulses and high percussion sound. The results of these studies are given.

Acupuncture Points↗
PubMed1994

Studies of the distribution and functional roles of transitory amoeboid microglial cells in developing rat brain using exogenous horseradish peroxidase as a marker.

When HRP was injected intraperitoneally (i. p.), labelled amoeboid microglial cells (AMC) were consistently localized in the subcortical white matter and circumventricular zones in early postnatal (1 and 7 days old) but absent in late postnatal (14-day-old) rats. The ingested HRP disappeared from the labelled cells 5 days after IP injection. Subcutaneous injection of HRP had also resulted in the labelling of amoeboid microglial cells in the corpus callosum of early postnatal rats. When the injected HRP was followed ultrastructurally over a time course sequence in intravenously (i. v.) injected rats, it was first detected in the invaginations on the luminal side of endothelium and in the endothelial cytoplasm 30 min after injection. HRP was present both in the endothelium and amoeboid microglial cells 3 hours later. With time, the tracer was progressively accumulated in the cytoplasm of AMC and it was sequestered in the vacuoles and lysosomes. It is concluded from this study that when injected i. p., i. v. or subcutaneously in the early postnatal rats, HRP is circulated to the blood vessels in the subcortical white matter and circumventricular zones where it gains access into the nervous tissues by transendothelial transport. The extravasated tracer is then phagocytosed by the residential AMC and subsequently degraded. The absence of labelling of AMC is attributed to the maturation of BBB which impedes the entry of exogenous tracer by the 14th postnatal day.

Aging↗
PubMed1994

[Correction of severe epicanthus using the square-flap method].

The square-flap method has been adopted gradually in plastic surgery because of lengthening effectively the distance between two points on the skin surface. Good results have been obtained in the treatment of severe epicanthus in 14 cases of 26 eyes by using modified square flap since 1990. This paper describes the operation design, advantages and key points of the surgery.

Adolescent↗
PubMed1994

[Effects of hypoxia-induced endothelin release on the proliferation of pulmonary artery smooth muscle cells].

On the Co-culture model of pulmonary arterial endothelial cells (PECs) and smooth muscle cells (PSMCs), we studied the effects of hypoxia on the release of endothelin in cultured PECs and whether or not these effects could trigger the proliferation in PSMCs. Increase of the transcription of ET gene in cultured pulmonary arterial endothelial cells was shown when endothelial cells were exposed to hypoxia for 24h (95% N2 + 5% CO2, PO2 40-45mmHg in media), was showed to increase the transcription of ET gene in cultured pulmonary arterial endothelial cells by using situ hybridization method. The secretion of ET-1 from those cells into media by ET-1 radioimmunologic detection while 3HTdr incorporation in cultured PMCs was higher compared with normoxia, and administration of ETAb significantly reduced the increase of the incorporation in those compared with hypoxia alone. These results showed that exposure to hypoxia can promote ET-1 gene expression in PECs as well as release of ET from those cells, which of ET can stimulate DNA synthesis in cultured PMCs. It is suggested that enhanced ET release from PECs under hypoxia could stimulate PSMCs' proliferation which may induce pulmonary vessel remodeling--which may involve in the development of hypoxic pulmonary hypertension.

Animals↗
PubMed1994

[The effect of a promoter P28-1 of Bacillus subtilis on Streptomyces differentiation].

A 1.1kb promoter P28-1 was inserted into pUC19. After then, the P28-1 was subcloned into the HindIII-EcoRI sites of the high copy number Streptomyces promoter probe plasmid pIJ4083 containing xy1E reporter gene. This recombinant plasmid was designated as pIJ4498. When pIJ4498 was introduced into Streptomyces coelicolor J1501 protoplasts, transformants conferred a white phenotype, whereas the vector pIJ4083 gave rise to colonies of normal, dark grey appearance which is the same as that of J1501 itself. After confirming pIJ4498 structure with some restriction enzymes, it was also introduced into whiG mutant (C71). Crude enzyme extracts were isolated from J1501/pIJ4498, J1501/pIJ4083 and C71/pIJ4498 respectively, the crude enzyme extract from J1501/pIJ4498 could oxidize catechol (colourless) to 2-hydroxy muconic semialdehyde (yellow colour), but crude enzyme extracts from J1501/pIJ4083 and C71/pIJ4498 could not oxidize catechol to 2-hydroxymuconic semialdehyde. The results indicated that P28-1 might be recognised by sigma whiG RNA polymerase, and activated the xylE reporter gene expression and reduced J1501 sporulation.

Bacillus subtilis↗
PubMed1994

[A new diarrhea pathogen: entero-SLTs-producing and invasive Escherichia coli was over-looked as normal flora E. coli].

In clinical laboratories of Beijing, China, no known entero-pathogen but almost pure E. coli strains could be isolated from more than 60% fecal samples of diarrheal patients, which had been recognized as normal flora E. coli and dismissed. We suspected that some of the so-called normal flora E. coli strains might be virulent. To prove our idea. We collected 172 strains of E. coli isolated from diarrheal patients from whom no other enteric bacterial pathogens had been identified, including EPEC, EIEC, ETEC. With plasmid DNA analysis, Hep-2 cell adherence assay and 10 DNA probe hybridization, we found that the so-called normal flora E. coli was abnormal, 44% of them were virulent, of which 16 (9.3) were EHEC, 8 EPEC (4.7%), 11 EAggEC (6.8%). Fifty-four of 172 strains were hybridized with INV and SLT1 or SLT2 probes, which had never been reported. These strains could invade Hep-2 cells, but were lack of ipaB gene, a key gene of invasiveness gene cluster of Shigella species and EIEC. The aggregative adherence to Hep-2 cells was observed, but the strains were not hybridized with EAggEC specific DNA probe. The purified toxin protein and cell filtrate were toxic to vero cells. Based on the data obtained, we believed that this is a new category of diarrhea-genic E. coli, named as entero-SLTs-producing and invasive E.coli (ESIEC). ESIEC occupied 31.4% of the strains tested, the isolation of it was probably higher than those of ETEC, EPEC in P R China.

Adult↗
PubMed1994

[The modifications in the evaluation of standard of hand function].

On the basis of the international evaluation of impairment of hand function, we propose five improvements: (1) For the evaluation of the impairment of thumb opposition and adduction, calculating the ratio of two distances takes the place of measuring a pure distance. (2) Hand sensory impairment evaluation is based upon both results of a sensory examination and a two-point discrimination test. (3) On the evaluation of amputation percentages related to whole hand, measuring loss of length is replaced by measuring loss of area. (4) On the evaluation of a joint, we correlated the combined angular measurement with the loss of length. (5) In the international evaluation of impairment of hand function, the sensory or amputation of the palm and back of the hand is not counted. But they are counted in our paper. Besides above-mentioned works, we have made a software with these improvements. You may obtain definite impairment percentages related to whole hand, so long as you input the results of examination of hand function.

Adult↗
PubMed1994

[Evaluation of echocardiography for determining left ventricular function].

Left ventricular ejection fraction (LVEF) was calculated by echocardiography and gate blood pool (GBP) in 33 patients including those with coronary heart disease, acute and old myocardiac infarction, cardiomyopathy or mitral prolapse. Fourteen of the 33 had segmental wall motion abnormalities and 19 had non-segmental wall motion abnormalities. The results of comparing echocardiography and GBP showed that the former could substitute for other invasive and expensive examinations to determine LVEF (r = 0.804-0.964 in the 5 echocardiography methods used). Mod-Simpsons method of cross-sectioned echocardiography was the most accurate echocardiographic method (r = 0.964, sensitivity 90.9%) in all patients. The Teich method of M-mode echocardiography was useful in patients who had non-segmental wall motion abnormalities only (r = 0.957, sensitivity 94.7%) but not in patients who had segmental wall motion abnormalities (r = 0.703, sensitivity 42.9%).

Adult↗
PubMed1994

[Mitochondrial DNA mutations in patients with myocardial diseases].

Amplification of one of the frequently deleted regions of myocardial and lymphocytic mitochondrial DNA (mt DNA) from patients with dilated cardiomyopathy (DCM), acute myocardial infarction (AMI) and normal controls was carried out with polymerase chain reaction (PCR). The results showed that multiple deletions exist in mtDNA of both patients and normal controls. 7.8 kb deletion was detected in myocardial mtDNA of 2 patients with AMI and 10 patients with DCM; 7.47, 8.10, 8.32 and 8.48kb deletions were found in lymphocytic mtDNA of 3 patients with AMI and 25 patients with DCM as well as 14 normal controls. The incidence and abundance of the 7.47kb mtDNA deletion increased with age of all the subjects studied. Quantitative analysis showed that mutated mtDNA accumulated up to 10% of total mtDNA-only in some older patients. Single strand conformational polymorphism analysis of the amplified 8,530-9,333 fragment allowed us to find a point mutation in a patient with DCM. Clinical significance of the mutations in mtDNA was discussed.

Adolescent↗
PubMed1994

[The diagnostic value of the assay of lactate dehydrogenese combined with other tumor markers in ovarian cancer].

Thirty-five cases of ovarian cancer, 35 ovarian benign tumors, 31 other gynecologic cancer and 35 normal controls were assayed for LDH, LDH-isoenzyme, SA, CEA, beta 2-MG and AKP. The results showed: (1) The average content of tumor markers in ovarian cancer was higher than benign tumor and healthy controls. (2) The positive rate of tumor markers in stage I and II patients of ovarian cancer was lower than in stage III and IV. (3) In the tumor markers, the diagnostic value of LDH-isoenzyme for ovarian cancer was best. (4) Combined assaying LDH, LDH-isoenzyme and SA was superior to using one marker for the diagnosis of ovarian cancer.

Adolescent↗
PubMed1994

Studies of the ultrastructure and permeability of the blood-brain barrier in the developing corpus callosum in postnatal rat brain using electron dense tracers.

The ultrastructure of the capillaries and their permeability to lanthanum ions and ferritin in the corpus callosum was examined in postnatal rat brain. In 1 and 7-d-old rats, numerous pinocytotic vesicles were observed in the endothelial cytoplasm of the callosal capillaries. Tight junctions were present between adjacent endothelial cells which were surrounded by an ill defined layer of basal lamina. The latter was almost devoid of astrocytic association in 1 d rats and partially covered by astrocytic end-feet in 7 d rats. Pericytes were a common feature. Amoeboid microglial cells were in direct contact with some parts of the vascular wall. Large extracellular spaces were present around the capillaries. In 14 d rats, the walls of the callosal capillaries became more well developed and were surrounded by a continuous sheath of astrocytic end-feet. The basal lamina became denser and well defined. The pericapillary spaces had diminished. Immunostaining for GFAP confirmed that, with age, the walls of the callosal capillaries became increasingly covered by the astrocytic end-feet. After perfusion with lanthanum, the tracer was deposited on the luminal surface but not in the abluminal side of the endothelial cells; the passage of the tracer was apparently obstructed in the intercellular space by the tight junctions in both the 1 and 14 d rats. When injected intravenously in 1-7 d rats, ferritin was transported across the endothelial cells by transcytosis and consequently taken up by the pericytes and amoeboid microglial cells contacting the basal lamina. In 14 d rats, the injected ferritin was only found in the endothelial cytoplasm. It was concluded that the difference in the capillary permeability to exogenous material in 1-7 and 14 d rats is due to the difference in the activities of the transendothelial transport. The pericytes and amoeboid microglial cells associated with the capillary probably play a role as phagocytes in maintaining the function of the blood-brain barrier by trapping any serum-derived foreign substances with astrocytes having a regulatory role in the formation of the barrier.

Animals↗
PubMed1994

Upregulation and induction of surface antigens with special reference to MHC class II expression in microglia in postnatal rat brain following intravenous or intraperitoneal injections of lipopolysaccharide.

The effects of bacterial lipopolysaccharide (LPS) on the expression of surface antigens including major histocompatibility complex (MHC) and complement type 3 (CR3) receptors on microglial cells in the corpus callosum in postnatal rat brain were investigated. When LPS was injected intravenously (i.v.) in 1-d-old rats, the immunostaining of callosal amoeboid microglial cells with OX-18 directed against MHC class I antigen was enhanced 24 h after the injection in comparison with the controls. The expression of MHC class II (Ia) antigen on the same cell type as shown by its immunoreactivity with OX-6 was also elicited especially after 2 intraperitoneal (i.p.) injections of LPS. Thus 7 d after a single i.p. injection of LPS into 1-d-old rats, only a few OX-6 positive cells showing a moderate staining reaction were observed in the corpus callosum. The immunoreactivity diminished 14 d after the injection. However, in rats receiving 2 successive i.p. injections of LPS at 1 and 4 d of age and killed 7 d after the 1st injection, a significant number of intensely stained OX-6 positive amoeboid microglial cells were observed in the corpus callosum. The expression of MHC class II antigens induced by 2 injections of LPS was sustained at least until d 14 when the callosal ramified microglial cells, known to be derived from gradual metamorphic transformation of amoeboid microglia, still exhibited intense immunoreactivity with OX-6. The effect of LPS on the expression of CR3 on amoeboid microglial cells was not obvious after a single injection, but the immunoreactivity with OX-42 was also augmented in rats given 2 i.p. administration of LPS into rats at 1 an 4 d of age. It is concluded from this study that the expression of MHC class I and class II antigens on amoeboid microglial cells in corpus callosum was upregulated and induced respectively after i.v. or i.p. injection of LPS into early postnatal rats. Although relatively fewer in number when compared with OX-18 and OX-42 positive cells, it is suggested that the OX-6 positive cells would have the potentiality to function in antigen presentation in the postnatal rat brain when challenged by the endotoxin.

Animals↗
PubMed1994

Impaired esophageal emptying in reflux disease.

OBJECTIVES: The symptoms and mucosal damage that occur in gastroesophageal reflux disease (GERD) may be a consequence of either an increased frequency of reflux events or of a prolonged process of esophageal acid clearance. Acid clearance is dependent both upon effective esophageal emptying of luminal fluid and on normal salivary function to titrate residual acid to neutrality. This investigation examined the efficacy of esophageal emptying in a large group of GERD patients. METHODS: Barium swallow examinations were done to categorize and quantify esophageal emptying dysfunction in 67 consecutive patients with reflux disease, compared with 85 patient asymptomatic controls. Quantitative fluoroscopic estimates of esophageal residua were compared with scintigraphic quantification in 14 controls and 20 GERD patients. RESULTS: There was progressive impairment of esophageal emptying in the reflux patients without esophagitis compared with the controls, and it was even greater in patients with endoscopically evident esophagitis compared with reflux patients without esophagitis. Good correlation existed between the fluoroscopic and scintigraphic assessment of esophageal emptying. CONCLUSIONS: These findings support the hypothesis that impaired esophageal emptying is an important determinant in the development of esophagitis among reflux patients. The dominant site of impaired emptying in the reflux patients was the phrenic ampulla as opposed to the tubular esophagus, suggesting a pathophysiological contribution of hiatus hernia.

Adult↗
PubMed1994

[A new species of Pseudomonas].

A strain No. 9191 isolated from fruit juice mineral drink is gram-negative short-rod. It differs from reported species of Pseudomonas in morphological, physiological and biochemical characteristics. Main characteristics of No. 9191 are single polar flagelled, oxidase and catalase positive, no acid from glucose but producing alkali, nitrate reduced to nitrite, inability to hydrolize gelatin and starch, arginine dihydrolase absent, no growth in presence of 0.85% NaCl. The G+C mol% of DNA is 65.15. It is named Pseudomonas halosensibilis Zou & Cai nov. sp. by the sensibility property for salt.

Beverages↗
PubMed1994

Lipopolysaccharide-neutralizing antibody reduces hepatocyte injury from acute hepatotoxin administration.

Endogenous lipopolysaccharide has been implicated as a cofactor in the hepatocellular injury and death resulting from toxic liver injury. To prevent this lipopolysaccharide-induced injury and to further understand the mechanism of this effect, an anti-lipopolysaccharide antibody was administered to rats in which toxic hepatocellular injury was induced. Rats were given the hepatotoxin galactosamine together with an isotypic control antibody B55 or the anti-lipopolysaccharide antibody E5. E5 treatment resulted in reductions of serum AST levels of 43% at 36 hr (p < 0.02) and 60% at 48 hr (NS) after galactosamine administration. These decreases in AST values were accompanied by diminished histological evidence of injury and inflammation. In carbon tetrachloride-induced liver injury, E5 similarly reduced serum AST levels at 36 and 48 hr by 47% (p < 0.04) and 54% (p < 0.03), respectively. E5 treatment was equally effective in reducing AST levels 48 hr after administration of carbon tetrachloride, whether the initial dose of antibody was given 1 hr before or 3 or 6 hr after the administration of this toxin. To understand the mechanism of this E5 effect, the activation of the toxic cytokine tumor necrosis factor-alpha and the chemotactic cytokine monocyte chemoattractant protein 1 was examined by Northern-blot analysis of RNA from rat livers after galactosamine-induced injury and treatment with B55 or E5. Despite E5's efficacy in reducing hepatocellular damage, E5 treatment did not affect the timing or magnitude of tumor necrosis factor-alpha or monocyte chemoattractant protein 1 activation during galactosamine-induced injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗