Biomedical subjects

S Duan

Publications and source records attributed to S Duan.

43 records · Page 3Linked to original sources

PubMed1994

[Survey on the current situation of epidemic of HIV infection in Yunnan Province].

This paper summarized the results of routine surveillance, sentinel surveillance in Yunnan province during the period of 1986 to 1992. In 1992, HIV infection rates of intravenous drug users (IDUs) were 80.7% in Ruili city, 43.0% in Longchuan county, 17.4% in Yinjiang county, 3.7% in Luxi county and 0 in Kunming city respectively; the comparison of the change on the HIV infection rate of IDUs between 1990 and 1992 showed that the rate in Ruili city increased by 12.8%, the rate in Longchuan grew by 8.2%, but the rate in Luxi did not go up. On the sentinel surveillance, the rates in Longchuan drug treatment center went up. In Shimao, the HIV positive were detected in prostitutes and the HIV positive rate was 3.6%. In Xishuangbanna, the HIV positive percentage among sex clients was 9.1%.

China↗

PubMed1994

Free radical mechanism in enhancement of radiosensitization by SRSBR.

The free radical mechanism of enhancing radiosensibility by the Synergic Recipe to Strengthen Body Resistance (SRSBR) consisting of 10 Chinese drugs was studied by electron spin resonance (ESR) with spin trapping reagent--Nitroso-tert-butane (NtB) following irradiation of the Deoxy thymidine (dT) solution system by 60Co 3.7 PBq. The results showed SRSBR cannot only enhance the generation of e- aq but also enhance the production of . OH and H . after irradiation with gamma ray in dT-NtB-SRSBR aqueous solution system. These result in damage to biological molecules, attacking and killing tumor cells radiosensitized by SRSBR. The characteristics of SRSBR for radiosensitization are concluded to be increasing production of . OH and H. in comparison with the well-known radiosensitizer-Misonidazole (Miso).

Cobalt Radioisotopes↗

PubMed1993

Cohort study of HIV infection among drug users in Ruili, Longchuan and Luxi of Yunnan Province, China.

In March 1992, KAP investigation and HIV blood test were carried out for 860 drug users and 82 spouses in Ruili, Luxi, Longchuan of Yunnan Province, China. The results showed that there were 285 injecting drug users (IDUs) (33.1%) among 860 drug users. Among 282 blood samples of IDUs, the HIV infection rate was 49.0%, highest in Ruili (81.8%, 63/77), then Longchuan (44.6%, 74/166), lowest in Luxi county (5.1%, 2/39). Twelve new HIV(+) were found from 75 persons, who had been tested as HIV(-) in recent two years. Sixty-two blood samples were collected among 82 spouses of IDUs with HIV(+), and 6 were HIV(+) (9.8%), with an increase of 6.7% compared with results of the investigation two years ago (3.1%, 2/64).

China↗

PubMed1992

Electrophysiological study of neurotropin-induced responses in guinea pig hypothalamic neurons.

To investigate the direct actions of neurotropin (NSP, a nonproteinaceous extract from inflamed skin of rabbits which is in therapeutic use), intracellular recordings were made from neurons of the ventromedial hypothalamic nucleus (VMH) and lateral hypothalamic area (LHA) in slices of guinea pig brain. In the VMH, NSP, applied by perfusion (0.1-3.0 NU/ml), caused dose-dependent depolarization in 29 of 48 neurons (60%) tested. No change in membrane resistance was observed during the depolarization, which hypothesized that the NSP-induced depolarization might be mediated through the inactivation of the Na-K pump. The NSP-induced depolarization persisted even after the elimination of synaptic activity by perfusion with Ca(2+)-free and high Mg2+ Ringer solution. NSP hyperpolarized the cell membrane of three neurons (6%) while two neurons (4%) showed biphasic responses; transient depolarization followed by long-lasting hyperpolarization. Membrane potential of the remaining 14 neurons was not changed by application of NSP. Of 14 LHA neurons tested for NSP effects, eight (57%) were depolarized, three (21%) were hyperpolarized, and one showed a biphasic response. The present results suggest that NSP significantly modulates hypothalamic neuron activity, and the central modulation of autonomic functions by NSP might be mediated through hypothalamic neurons.

Animals↗

PubMed1990

Hypothalamic neuronal activity responses to 3-hydroxybutyric acid, an endogenous organic acid.

To elucidate the anorectic action of the endogenous organic acid, 3-hydroxybutyric acid (3-HBA), its effects on neurons in both the rat ventromedial hypothalamic nucleus (VMH) and the lateral hypothalamic area (LHA) were examined. Iontophoretic application of 3-HBA significantly facilitated the firing rate of VMH neurons, whereas facilitation and inhibition were observed in the LHA. These responses were specific to the glucoreceptor neurons in the VMH and glucose-sensitive neurons in the LHA. Intracellular recordings from brain slice preparations revealed that 3-HBA depolarized the cell membrane of the VMH neuron with an associated increase of membrane input resistance. This was similar to the effect of glucose on glucoreceptor neurons in the VMH. These results suggest that 3-HBA may modulate hypothalamic chemosensitive neuron activity as well as function as an endogenous satiety factor.

3-Hydroxybutyric Acid↗

PubMed1990

[Adjustable action of pi-shen recipe on immune function in mice with L1210 ascites].

Proliferation of Con A stimulated splenic lymphocyte was examined by incorporation of 3H-thymidine. Fluorescence polarization of DPH labelled splenic lymphocyte and bone marrow cells was measured. Proliferation of Con A stimulated splenic lymphocyte in DBA inbred healthy mice was higher than that of L1210 mice but fluorescence polarization of DPH labelled splenic lymphocyte in same healthy mice was lower than that of L1210 mice. i.e. membranous lipid lymphocyte fluidity of lymphocyte in the healthy mice was smaller than that of L1210 mice. 9 days after administration of Pi-Shen recipe by tube stomach proliferation of Con A-lymphocyte in the healthy mice has been increased. The recipe adjusted splenic lymphocyte membrane lipid fluidity of L1210 mice to level of those in healthy mice. Effects of Pi-Shen recipe on lipid fluidity of bone marrow cell membrane of L1210 mice were almost similar to that in splenic lymphocytes. These studies suggest that the mechanism on adjustable role of Pi-Shen recipe on T-lymphocyte function related to lymphocyte membrane lipid fluidity.

Animals↗

PubMedDate not supplied

A new immune escape mutant of hepatitis B virus with an Asp to Ala substitution in aa144 of the envelope major protein.

A new hepatitis B virus (HBV) mutant with an Asp to Ala substitution in aa144 of the envelope major protein was identified from the blood samples of two persistently infected patients. They were born to HBsAg-positive carrier mothers. The patients had been immunized with HBV vaccine after birth, under a standard schedule of 3 injections at 0, 1 and 6 months, but failed to be protected. The mutant was stable and was present in the blood samples collected at 1 and 4 years of age from patient 105. To study the antigenic differences, two expression plasmids, pExpW (wild type) and pExpM (mutant), were constructed, and HBsAgs were expressed in COS-M6 cells. The binding activities of the HBsAg from pExpW and pExpM were compared with anti-a-epitope monoclonal antibody and with anti-HBs polyclonal antibody, respectively, by radioimmunoassay. The results showed that the binding activity of HBsAg of pExpM was distinctly lower than that of pExpW, and the HBV mutant with envelope major protein144Asp-->Ala was shown to be a new immune escape variant.

Alanine↗