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Biomedical subjects

J Lu

Publications and source records attributed to J Lu.

At least 577 records · Page 32Linked to original sources
PubMed1994

Collectins, collectin receptors and the lectin pathway of complement activation.

The collectins are a group of soluble multimeric lectins, which contain collagenous segments, and resemble the complement protein C1q in aspects of their structures and functions. This group of proteins, which includes MBP, SP-A, SP-D, conglutinin and CL-43, are known to act as opsonins in various circumstances, and are likely to have roles in innate immunity. The focus of current research is to pursue the hypothesis that the collectins recognize and bind to non-host carbohydrate structures on microorganisms and particles, and participate in the processing or elimination of such material, either by direct interaction with phagocytic cell receptors, or by indirect routes such as complement activation .

Animals↗
PubMed1994

Immunophenotypic features of epiplexus cells and their response to interferon gamma injected intraperitoneally in postnatal rats.

The expression of major histocompatibility complex (MHC) antigens (class I and II), type 3 complement receptor (CR3) and leucocyte common antigen (LCA) was examined in epiplexus cells in rats of different ages. The cells exhibited intense immunoreactivity with the monoclonal antibody OX-42 which recognizes CR3 receptors. In early postnatal rats (1 d), the immunolabelled cells were mostly round but with increasing age (7 wk), they assumed a ramified or elongated form. The expression of LCA marked by the monoclonal antibody OX-1 followed a similar staining pattern. Class I MHC antigen expression was also demonstrated in some epiplexus cells using the monoclonal antibody OX-18 but they were less numerous than the OX-42 or OX-1 positive cells. Only sporadic OX-6 positive cells were observed in postnatal rats but they showed a marked increase in number in adult rats, suggesting an upregulation of class II MHC antigens with age. The expression of MHC class II antigens was vigorously elevated in postnatal rats receiving 6 successive intraperitoneal (i.p.) injections of interferon gamma (IFN-gamma). In these animals, a large number of intensely stained OX-6 positive epiplexus cells were observed. These were mostly elongated or ramified with long processes. The immunostaining of epiplexus cells with OX-18 was also enhanced after IFN-gamma injections but the expression of CR3 and LCA appeared to be unaffected. It is concluded that the expression of MHC class I and II antigens on epiplexus cells is upregulated and induced respectively after successive i.p. injections of IFN-gamma into postnatal rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Immunoelectronmicroscopic study of fibronectin in Kupffer's cell in rats with multiple organ failure].

This essay studied the content and distribution of Fibronectin (Fn) in Kupffer's cells in rats with multiple organ failure (MOF) with the immunoelectronmicroscopy technique. The results revealed that there was a significant increase in Fn level in plasma and the amount of immunogold particles in Kupffer's cells during the early stage, but the changes were not evident in the late stage. Our findings indicated that the changes in content of Fn was closely related to the function of MPS and might play an important role in the pathogenic mechanism of MOF.

Animals↗
PubMed1994

[Long-term clinical observation on VCu200 intrauterine devices].

A comparative study was carried out in 350 women using VCu200 intrauterine devices (IUD) and 350 women using stainless steel ring (SSR) IUD for 5-18 years. The endometrial changes and shapes of IUD were studied. The results showed that the pregnancy rate was significantly lower in VCu200 group after 5 years of insertion. In spite of the oxidation, erosion or breakage of the copper wire, calcium deposit of even deformation of the IUD, they were not associated with an increased incidence of endometrial carcinoma and pelvic inflammatory disease. It is suggested that VCu200 IUD need not to be removed if the IUD keeps normal shape and the copper wire remains intact by X ray examination.

Endometrium↗
PubMed1994

A new experimental and clinical approach of combining usage of highly active tumor-infiltrating lymphocytes and highly sensitive antitumor drugs for the advanced malignant tumor.

In recent years, tumor-infiltrating lymphocytes (TILs) have been reported to be effective for tumors in experimental and clinical research. In order to increase the therapeutical effect, we modified some steps of Rosenberg's approach: a. cold digestion with collagenase at 4 degrees C for 24 hours; b. sedimentation instead of centrifugation; c. elimination of tumor cells before the cultivation procedure. Compared with the original approach, the proliferation, activity and cytotoxicity of TILs obtained by the modified procedure were much improved. TILs' expansion-fold was greater than that with the original approach. Cytotoxicity against tumor cells was more potent. Increased TILs' subsets were CD3 and CD8 cells. Meanwhile, we took tumor cells from tumor tissues to test their in vitro chemosensitivities to different drugs in order to select highly sensitive antitumor drugs for treatment of cases with advanced tumors. According to the design of using highly active TILs and highly sensitive drugs (H & H therapy), preliminary clinical results of 50 cases showed higher response rates than those in treatment with TIL/IL2, LAK/IL2 and TIL+IL2+CTX. Less toxic side effects were observed in 14 patients.

Antineoplastic Agents↗
PubMed1994

[Meta-analysis and its application in epidemiology].

Meta-analysis provides a powerful statistical tool for epidemiological study. The basic principle of meta-analysis is introduced in this paper, and some problems about its application in epidemiology are discussed. This method was used by the authors to study the relationship between exposure to extreme low frequency electromagnetic fields (ELF) and childhood leukemia, and the result showed that there is a significant association between them.

Electromagnetic Fields↗
PubMed1994

[Study on risk factors of 292 pregnant women infected with HCMV].

This paper is to determine the risk factors of reactivation by HCMV during pregnancy for improving child birth and bringing-up. A total of 292 paired sera were collected from mothers and their infants in Shanghai and were tested for IgG and IgM by ELISA. The positive rates of HCMV IgG and IgM were 98.97%, 96.97% and 3.77%, 1.71%, respectively in mothers and infants. The rate of IgM was 1.49% in infants whose mothers' education were above the high school level, whereas it was 4.17% whose mothers' educational degree was lower than that grade, and the relative ratio (RR) was 2.8. The number of previous pregnancies were closely associated with the positive rate of IgM. In infants born to mothers at first pregnancy, the positive rate was 1.96%, whereas in infants born to mothers at third pregnancy it increased to 3.70%, RR was 1.89. In pregnant women who were known to have postmortem or premature deliveries before the positive rate was 9.09%, whereas it was 2.53% in pregnant women at first pregnancy, the RR was 3.59. The rates of their infants were 3.03% and 1.90%, respectively, the RR was 1.59. The frequency of IgM antibody in 292 sera of mothers was correlated with that in their infants. It showed that HCMV might be transmitted from mother to fetus.

Adult↗
PubMed1994

The cardiac effects of a novel A1-adenosine receptor agonist in guinea pig isolated heart.

Adenosine increases atrioventricular (AV) nodal conduction time and is used for termination of AV nodal re-entrant tachycardias, but it is rapidly metabolized. The purposes of the present study were to characterize the cardiac actions and effects of an orally active and stable adenosine analog, N6-cyclohexyl-2-O-methyladenosine (SDZ WAG-994) and to evaluate its potential as an antiarrhythmic agent. Guinea pig hearts were isolated and perfused with oxygenated Krebs-Henseleit solution. SDZ WAG-994 slowed the atrial rate and prolonged the AV nodal conduction time of spontaneously beating hearts in a concentration-dependent manner. The EC50 values for the negative chronotropic and dromotropic effects of SDZ WAG-994 were 0.69 +/- 0.04 and 1.49 +/- 0.54 microM, respectively. The A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (0.2 microM) significantly antagonized SDZ WAG-994-induced stimulus-to-His bundle (S-H) interval prolongation. The negative dromotropic effect of SDZ WAG-994 showed very strong frequency dependence. In hearts paced at an atrial cycle length of 300 msec (200 beats/min), the EC50 value of SDZ WAG-994 to prolong the S-H interval was 3.7-fold lower (0.40 +/- 0.02 microM) than in unpaced hearts, and at atrial pacing cycle lengths of 500 and 250 msec, 0.3 microM SDZ WAG-994 prolonged the S-H interval by 8 and 26 msec, respectively. SDZ WAG-994 also decreased coronary perfusion pressure (EC50 = 1.50 +/- 0.80 microM); this effect of SDZ WAG-994 was attenuated by adenosine deaminase and by 8-cyclopentyltheophylline (2 microM). Radioligand binding assays revealed that SDZ WAG-994 had a 280-fold greater affinity for A1- than for A2a receptors of the guinea pig brain. The marked frequency dependence of the negative dromotropic effect of SDZ WAG-994 suggests that this A1 agonist may be highly effective in the termination of AV nodal re-entrant tachycardias.

Adenosine↗
PubMed1994

Effects of toosendanin on electric and mechanical properties of guinea pig papillary muscles.

Effects of toosendanin (TS) on the action potentials and contractile force in guinea pig papillary muscles were examined using a standard microelectrode technique. TS concentration-dependently increased the action potential duration at 90% repolarization (APD90) of the fast action potentials. In the presence of a Ikl channel blocker BaCl2, the effects of TS on lengthening the APD90 were completely abolished, thereby suggesting that TS inhibited the inward rectifier K+ current Ikl. The APD and contractile force of aminophylline-induced slow action potentials were potentiated by TS in a concentration-dependent manner. In the presence of BaCl2, both effects of TS were completely abolished. The effect of TS on enhancing contractile force was abolished by the addition of CdCl2, with the prolongation of APD preserved. Thus, TS selectively inhibited the inward rectifier K+ current Ikl with a positive inotropic effect, resulting from a delay in Ca channel inactivation which was secondary to delay in ventricular repolarization.

Action Potentials↗
PubMed1994

[Study on the influence of enzymatic digestion upon tumor-infiltrating lymphocytes].

To get a long-term culture of tumor-infiltrating lymphocytes (TILs) is very difficult. The authors have investigated some suitable enzymes, their digestive conditions such as time and temperature, which may influence the viability and cytotoxicity of TILs. The results showed that collagenase II and IV could keep viability of TILs much longer than those treated with trypsin or hyaluronidase. The digestion with collagenase II or IV at 4 degrees C for 24 hours was much less damage to viability of TILs than those treated at 37 degrees C for one hour. The TILs, which digested at 4 degrees C for 24 hours, still had cytotoxicity against autologous tumor cells as long as sixty to seventy-five days.

Collagenases↗
PubMed1994

Does myocardial perfusion scintigraphy demonstrate clinical usefulness in patients with markedly positive exercise tests? An assessment of the method in a high-risk subset.

To evaluate the clinical utility of perfusion scintigraphy in patients with markedly positive exercise ECGs, we studied 94 consecutive patients with markedly positive exercise ECGs; 74 of them were also studied with scintigraphy. Patients undergoing scintigraphy had an intermediate pretest likelihood of coronary disease and were divided into two groups: those with reversible defects involving one complete area or aspects of multiple vascular areas (group 1, 38 patients), and those with normal scintigrams and reversible defects in a limited aspect of one vascular area, isolated fixed defects, or both (group 2, 36 patients). Among all demographic and exercise variables, only a hypotensive or blunted blood pressure response and scintigraphic lung uptake or cavitary dilation, although insensitive, were more frequent in group 1 (all p < 0.05). All 36 patients in group 1 and 14 of 18 in group 2 who underwent coronary angiography had significant coronary lesions; 31 in group 1 but only seven in group 2 had multivessel disease (p < 0.05). Subsequently 32 patients in group 1 had revascularization compared with only two patients in group 2. Only one cardiac event was noted among 34 patients in group 2 who were followed for a mean of 38 months while they were being treated medically. However, four of nine patients in group 1 initially treated medically required late revascularization because of clinical progression of disease, and one patient died (p < 0.05). Compared with patients having scintigraphy, patients not imaged had a higher pretest likelihood of coronary disease, a higher incidence of angina, unstable angina, and induced angina, with a lower exercise time and time to ST depression (p < 0.05). All underwent angiography, and 16 had multivessel disease. Not all patients with markedly positive exercise ECGs were at similarly high coronary risk. Some with high-risk coronary anatomy were identified without the use of scintigraphy. In others, where diagnosis and prognosis were less clear, scintigraphy aided in the diagnosis and accurately identified a low-risk subgroup as did no other parameter.

Aged↗