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Biomedical subjects

L Zhu

Publications and source records attributed to L Zhu.

At least 469 records · Page 26Linked to original sources
PubMed1992

[Effect electroacupuncture on the neurogenic inflammation].

The neurogenic inflammation caused by antidromic stimulation of the saphenous nerve was taken as an index of peripheral release of substance P. Electroacupuncture could reduce the plasma extravasation from the neurogenic inflammation by 69.7%, but electroacupuncture per se did not cause obvious plasma extravasation. In rats pretreated with capsaicin the plasma extravasation could be markedly reduced, in consistent with the reduction of substance P-like immunoreactivity in dorsal horn. It is referred that electroacupuncture might block the conveying the signals induced by nerve stimulation along the C-fibers and the axo-axonal reflex, leading to the reduction of peripheral release of substance P. Besides the mediation by different central structures, acupuncture might have direct effects on regulating peripherally the release of some inflammatory and painful mediators.

Animals↗
PubMed1992

Clinical and experimental studies on tong yu ling in the treatment of diabetic hyperlipemia.

72 diabetes mellitus patients (70 cases non-insulin-dependent) were treated routinely with D860. After one month, cases with persisting hyperglycemia and hyperlipemia were randomly divided into Group A to be treated with D860 plus Tong Yu Ling (TYL), and Group B to continue treatment with D860 alone, while Group C, comprising cases with persisting hyperlipemia only, were treated with TYL alone. Therapeutic results showed that of the total 50 cases of Group A and C, 26 were markedly improved, 14 improved, and 10 cases ineffective. The antihyperlipemic effect was pronounced in Group A, where the blood cholesterol, beta-lipoprotein and triglyceride showed remarkable decline, less pronounced in Group C, and insignificant in Group B. Experiments in rat models of non-insulin-dependent diabetes demonstrated that TYL was markedly effective in treating hyperlipemia.

Adult↗
PubMed1992

[Distribution of microfilaments in rat Sertoli cells in vivo and in vitro].

The distribution of microfilaments (MFs) in rat Sertoli cells in vivo and in vitro was studied with electron microscopy and the TRITC-phalloidin staining method. The results revealed the following: The MFs of the Sertoli cells in vivo are arranged in bundles just beneath the cell membrane. MF bundles may form a band-like structure circumscribing the basal region of each Sertoli cell. The filaments and bundles are parallel with each other and their arrangement is symmetrical on the opposite sides of two adjacent Sertoli cell membranes. In vitro, the arrangement and distribution of MF bundles are closely related with the living and spreading state of the cell. In a fully spread cell, MFs bundles are arranged in parallel just beneath the cell membrane. We conclude that MFs in rat Sertoli cells are mainly arranged in bundles and stretched beneath the cell membrane. They may play an important role in maintaining the shape of the cell and the blood-testis barrier.

Actin Cytoskeleton↗
PubMed1992

Histological examination of the auricular cartilage and pseudocyst of the auricle.

In our histological examination of 42 ears (auricles) which were taken from 18 fetus and three adults, the intracartilaginous fibrous tissue with blood vessels and lymphatics were found in 12 ears and interruption of the auricular cartilage in 22 ears. The intracartilaginous connective tissue with blood vessels and lymphatics were linked together with the connective tissue outside the auricular cartilage in other sections. These findings support the hypothesis of congenital embryonic dysplasia as the origin of the formation of pseudocyst of the auricle.

Adult↗
PubMed1991

[The effect of plaque fluid on demineralization of enamel powder].

The aim of this study was to explore any substance in dental plaque which might affect the demineralization of enamel. Plaque fluid was prepared by centrifugation of pooled plaque from 56 young adults without periodontal diseases. Enamel was separated from healthy teeth of adolescents and crushed into powder. The enamel powder was treated separately by plaque fluid and synthetic plaque fluid (as a control, with similar calcium, fluoride content and pH as the natural). After this, the enamel powder was washed with PBS. Both the plaque fluid-treated and synthetic plaque fluid-treated enamel powder were demineralized by mixed organic acid (pH 4.5). The calcium content in both plaque fluids, PBS and organic acid after treatment with enamel powder was analysed by atomic absorption spectrophotometer. The results showed that there was no promoting effect in plaque fluid on demineralization of enamel, but, on the other hand, some protecting action was observed which might contribute to the presence of proteins in plaque fluid.

Adult↗
PubMed1991

[The influence of vagotomy on stomach endocrine cells in rat].

UNLABELLED: The effects of unilateral truncal vagotomy (UTV) and bilateral truncal vagotomy (BTV) on antrum EC cells, G cells and oxyntic gland area argyrophil cells were studied in rats by using immunohistochemistry processes, Grimelius argyrophil stain and microscopic image analysis technique. RESULTS: (1) In UTV animals, two weeks postoperation, the sectional areas of EC cells were significantly smaller in denervated side than In the other side (17%, P less than 0.05). In the innervated side of antrum, the sectional areas of EC cells were larger than those in controls (13.5%, P less than 0.05). But, five weeks after UTV, the size of EC cells was not significantly different in all animals. These suggest that vagal denervation can inhibit relatively the functional activity in a short period, but this inhibition could be compensated later. (2) There were no morphological changes in G cells of UTV rats. In BTV animals, the quantity of G cells in antrum increased by 36.2% (P less than 0.05) and their sectional areas were larger than those in sham by 26.2% (P less than 0.05). These indicate that the function of G cells is more active in BTV animals and the functional change of G cells is related to the pH value of gastric juice. (3) In UTV rats, the oxyntic gland area argyrophil cells (ECL cells are dominant) were significantly reduced in two weeks (26.8%, P less than 0.01) and in five weeks (20.1%, P less than 0.05) in denervated side after UTV. The cells became smaller also. These suggest that vagus can influence the function, proliferation and growth of ECL cells.

Animals↗
PubMed1991

[Hemolytic reaction resulting from propafenone administration].

Although adverse reactions of many kinds caused by propafenone have been observed, yet there has been no documented report of hemolytic reaction. Four episodes of hemolytic reaction in three patients receiving intravenous propafenone were reported. These reactions took place a few hours after the administration and one of the episodes was complicated with acute left ventricular heart failure and shock. Cessation of propafenone administration together with relevant therapeutic measures tide the patients over and hemolysis disappeared in several hours. Toxicological examination revealed no physical or chemical deterioration and biological contamination of the remaining medication and no such reaction was noted when the drug of the same batch was given to other patients. It is considered that the hemolytic episodes were related to allergic constitution of the patients. Judging from the clinical manifestations, these episodes were hemolytic reactions of immune complex type.

Anemia, Hemolytic↗
PubMed1991

O6-methylguanine-DNA methyltransferase and human cancer chemotherapy.

Two kinds of human tumor cell strains having different activity of O6-methylguanine-DNA methyltransferase (O6-MT) were transplanted into nude mice. Then the mice were injected intraperitoneally with bifunctional alkylating agent 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU). The tumors with low O6-MT activity were quickly suppressed or cured. The result suggests that some tumors, if provisionally determined with low O6-MT activity, might be efficiently cured by treatment with ACNU. This probably opens a new way for human cancer chemotherapy.

Animals↗
PubMed1991

Energy and dose-rate dependence of neoplastic transformation and mutations induced in mammalian cells by fast neutrons.

Since our original observation that low-dose, low-dose-rate JANUS neutrons produced more transformation in C3H 10T1/2 cells than equivalent doses at high dose rate (Hill, Buonaguro, Myers, Han, and Elkind, Nature 298, 67-69, 1982), there have been many reports on the dose-rate dependence of a variety of high-LET radiations. Some of these have qualitatively supported our original and subsequent observations, and some have found no evidence for a dose-rate effect. Thus there remain questions about the generality, size, tissue specificity, and reproducibility of these observations. Furthermore, there are no well-established mechanistic descriptions or observations to account for such effects. In this report studies are presented using a range of neutron energies produced by the UCLA cyclotron from 12- to 46-MeV protons on beryllium. In particular, emphasis is placed on comparing results between energies for neoplastic transformation and mutation end points, and preliminary data are presented on the molecular and mechanistic aspects of neutron-induced damage.

Animals↗
PubMed1990

Cytolysis of corneal epithelial cells by hydrogen peroxide.

Superoxide radicals or products generated by these radicals in a xanthine/xanthine oxidase system lyse cultured rat and human corneal epithelial cells as measured in a chromium-51 release assay. Partial protection from this lysis is afforded by superoxide dismutase and complete protection is obtained with catalase. Hydrogen peroxide, a product of the dismutation of superoxide radicals, lyses these cells directly and is implicated as the toxic agent in the xanthine/xanthine oxidase reaction. Hydrogen peroxide also decreases cell proliferation and decreases the intact DNA. Therefore, hydrogen peroxide appears to be toxic to corneal epithelial cells. The implications of these data on the safety of hydrogen peroxide as a contact lens disinfectant are discussed.

Animals↗
PubMed1990

Transcriptional control of the invariant chain gene involves promoter and enhancer elements common to and distinct from major histocompatibility complex class II genes.

The invariant chain (Ii) is a glycoprotein coexpressed with the major histocompatibility complex (MHC) class II antigens. Although Ii is encoded by a single gene unlinked to the MHC gene complex, Ii and MHC class II appear to have similar patterns of tissue specific expression and generally are coordinately regulated by cytokines. Here we present evidence that transcription of the murine Ii gene is controlled by multiple cis-acting elements. The 5' regulatory region of the Ii gene appears to be combined of conserved class II regulatory elements with promoter elements commonly found in other eucaryotic genes. A region containing characteristic class II promoter elements (H box, X box, and a modified Y box) serves as an upstream enhancer in the Ii gene and might contribute to the coexpression of MHC class II and Ii genes. A series of positive control elements, the kappa B element, Sp1-binding site, and CCAAT box, are present in the Ii promoter and apparently serve distinct regulatory functions. The kappa B site in the Ii gene is a cell type-specific element, contributing to expression in a B-cell line but not in a fibroblast cell line, and the Sp1 site is required by the H-X-Y' enhancer element to stimulate promoter activity. In addition, an Ii enhancer in the first intron that specifically stimulates its own promoter has been identified. Our results suggest that a sequence match between enhancers and certain promoter elements is critical.

Animals↗
PubMed1990

[The effect of several acids and proteolytic enzymes on the production of artificial caries].

Human tooth slabs were used to observe the effect of several kinds of organic acids and proteolytic enzymes on the production of artificial caries of enamel. Acidic gels were made by formic, acetic and lactic acids separately or in mixed form. The experiments were done in a period of 10 days. After this the specimens were prepared in ground sections and observed under optic microscope. The depth of the artificial lesions was measured by a micrometric scale in the eye lens of the microscope. The enzymes used for investigation were papain, trypsin and collagenase. The surfaces of the tooth were treated with fresh enzyme solutions every day and then with mixed acid gels. This was done alternately every day in a period of ten days. The results showed that lesions produced by formic acid gel were deeper than those produced by other acids or mixed acid gels. No effect was observed on the depth of the lesion by enzymatic treatments.

Acids↗
PubMed1990

[Scanning electron microscope observation on proximal enamel surfaces of normal teeth].

This observation was made on the proximal surfaces of normal permanent molars. Observations were concentrated mainly on those teeth with abraded contact areas on the mesial surface and the unabrasive distal surfaces if the partially or wholly embedded third molars. The results showed that the surfaces of the abraded contact areas were plain than those outside the contact. There were lots of pitted holes or fissures on the surfaces outside the contact areas. In the holes accumulations of bacteria could be seen. These holes and fissures could also be seen on the unexposed distal surfaces of the third molars, but no clear-defined traces of bacteria were observed in the holes.

Dental Enamel↗
PubMed1990

[The effect of laser irradiation on arthritis in rats].

Based on the analgesic effect of laser therapy in clinic, the effect of laser irradiation at acupoints on the experimental arthritis in rats was further observed. The experiments were carried out on Wistar rats, which were divided into three groups: The normal group (n = 6): without any treatment. The laser group (n = 8): 24 hours after an injection of Freund's adjuvant, the typical symptoms of acute arthritis (red, swelling, pain and hyperalgesia) occurred. Then transcutaneous irradiation with a low power Helium-neon laser (3 mw, 6328 A) at ipsilateral Kun-Lun point was applied ten minutes every day for five days. The control group (n = 8): with the same treatment as the laser group except laser irradiation. All the indexes, such as foot volume, pain score and pain threshold (Heat-leg-withdrawal latency, HWL and electric-shock vocalization, VOC) were measured every day. Comparing with the symptoms in the control group, the intensity of pain as measured on pain score and the swelling of the ankles (foot volume) were significantly reduced by laser irradiation (P less than 0.01), but the pain threshold (HWL and VOC) did not show any improvement in laser group. However, immediately after laser irradiation, the average pain threshold (VOC) was significantly raised (P less than 0.01). It is concluded that low power laser irradiation at local points can produce the relief from arthralgia and reduction in the swelling of ankles, and it can also produce instant analgesic effect in test of pain threshold (VOC).

Acupuncture Points↗
PubMed1990

[Therapeutic effects of electroacupuncture (EA) on acute experimental arthritis in rats].

The dynamic changes of the pain thresholds (Heat-Withdrawal Latency, HWL and Stimulation-Vocalization Threshold, Voc) in the adjuvant-induced arthritic rats and the effects of EA on the pain thresholds, skin temperature and the circumference of the diseased ankle were observed. Both pain thresholds were obviously decreased in affected limbs in EA and control groups. But in the normal limbs, HWL decreased and Voc, no changed. In EA group, the ankle circumference and skin temperature were markedly lower than that in control group. The increase of the body weight was much more obvious than that in control group. Our experiment revealed that EA could not only increase the pain threshold, but also improve the pathological changes in the inflammation of the ankle, the mechanisms of the changes of the pain thresholds and the effects of EA in the arthritic rats were discussed.

Acupuncture Therapy↗