PubMed Health⌕ Search

Biomedical subjects

W Ren

Publications and source records attributed to W Ren.

46 records · Page 3Linked to original sources
PubMed1994

Studies on the relationship between changes in radiographic bone height and probing attachment.

The aim of this investigation was to determine the relationship between loss of radiographic crestal bone height and probing attachment loss. As part of this aim, we are introducing a new method for determination of a threshold for significant probing attachment loss which takes into account the error contributed by alteration in tissue tone. 57 adults with established periodontitis were selected. Radiographs were taken using the Rinn alignment system. Crestal change was determined from bone height measurements on digitized images of pairs of radiographs using the "side-by-side" technique of analysis developed recently by us. Probing attachment loss was measured using the Florida electronic probe system. Radiographic and probing measurements were made at baseline and after 1 year. No treatment was given during this period. A direct and significant relationship was observed between radiographic bone loss and probing attachment loss on a site basis (p = 0.0001, r2 = 0.018) and between subject means (p = 0.0014, r2 = 0.16). Radiographic and probing attachment change at all categories of sites, dichotomously classified as to not changing or loosing indicated 13% of sites were loosing by measurement of radiographic change and 9.6% were loosing by measurement of attachment change. Concordance in radiographic and attachment level change was found in 82% of sites examined. The relative diagnostic import of change in probing attachment or change in radiographic bone height requires treatment outcome studies based on use of diagnostic information of the 2 measuring techniques used singly and in combination.

Adult↗
PubMed1992

Regulation of C-myc protooncogene expression in osteoblastic cells by arachidonic acid metabolites: relationship to proliferation.

Prostaglandin E2 and leukotriene B4 are metabolites of arachidonic acid with well-characterized effects on osteoblastic cells. Prostaglandin E2 has been shown to be a potent bone-resorbing agent and to stimulate as well as inhibit osteoblastic cell proliferation. Leukotriene B4 has also been demonstrated to stimulate or inhibit osteoblastic cell proliferation, depending on the cell type tested. In the present study, the potential relationship of the effects of prostaglandin E2 and leukotriene B4 on osteoblastic cell proliferation to c-myc protooncogene expression was investigated. Prostaglandin E2 has been shown previously to inhibit normal rat osteoblastic cell proliferation. The present studies show that prostaglandin E2 at 10(-6) M decreased c-myc expression in these cells. In the human osteoblastic osteosarcoma cell line, G292, prostaglandin E2 increased c-myc expression and inhibited proliferation. In contrast, epidermal growth factor increased DNA synthesis as well as c-myc expression. Prostaglandin E2 also inhibited proliferation of another human osteoblastic osteosarcoma cell line, Saos-2, but it did not produce any changes in c-myc expression. In these cells, epidermal growth factor did not affect either DNA synthesis or c-myc expression. Leukotriene B4 did not show any effects on c-myc expression in any of the osteoblastic cells tested.

Animals↗
PubMed1991

Effects of leukotrienes on osteoblastic cell proliferation.

Leukotriene B4 (LTB4) is an arachidonic acid lipoxygenase metabolite with well-characterized effects on leukocytes. LTB4 has been implicated in acute inflammatory reactions and in bone resorption. In the present study, the effect of LTB4 on osteoblastic cells was examined. LTB4 inhibited cell proliferation in normal osteoblastic rat calvaria cells in a dose-dependent manner and had biphasic effects in the human osteoblast-like osteosarcoma cell lines Saos-2 and G292. Indomethacin did not modulate the nature of these LTB4 effects in any of the cells. However, it potentiated the high LTB4 dose effects in normal cells and G292 cells. AA861, an inhibitor of lipoxygenase, did not modulate the LTB4 effects in these two cell lines. These results suggest that LTB4 is involved in the regulation of osteoblastic cell proliferation and may interact with prostaglandins to modulate these effects.

Animals↗
PubMed1991

[Segmental distributions of sensory neurons of the "ganshu", "pishu", "liangmen", "qimen" points and the gallbladder].

One hundred guinea pigs were used. The 10% HRP 50-60 microliters solution was injected into the acupoints of "Gansu", "Pisu", "Liangmen" and "Qimen" of every animal. Moreover, the 10% HRP 80-100 solution was injected into the gallbladder of the another animals too. Under the microscope, observed the segmental distributions of sensory neurons of the four acupoints and the gallbladder. It could be found much clearly that HRP labelled cells were appearing in the spinal ganglions. The above experimental studies showed that there are mutual intersect 5-7 segments between the gallbladder and the "Gansu", "Pisu", "Liangmen" and "Qimen" four acupoints. It is probable that the mutual intersect is the neuroanatomic foundation of acupuncture and moxibustion to inhibit the formation of bilirubin gallstones.

Acupuncture Points↗
PubMedDate not supplied

Dynamic change of ERPs related to selective attention to signals from left and right visual field during head-down tilt.

To study further the effect of head-down tilt (HDT) on slow positive potential in the event-related potentials (ERPs), the temporal and spatial features of visual ERPs changes during 2 hour HDT (-10 degrees) were compared with that during HUT (+20 degrees) in 15 normal subjects. The stimuli were consisted of two color LED flashes appeared randomly in left or right visual field (LVF or RVF) with same probability. The subjects were asked to make switch response to target signals (T) differentially: switching to left for T in LVF and to right for T in RVF, ignoring non-target signals(N). Five sets of tests were made during HUT and HDT. ERPs were obtained from 9 locations on scalp. The mean value of the ERPs in the period from 0.32-0.55 s was taken as the amplitude of slow positive potential(P400). The main results were as follows. 1) The mean amplitude of P400 decreased during HDT which was more significant at the 2nd, 3rd and 5th set of tests; 2) spatially, the reduction of mean P400 amplitude during HDT was more significant for signals from RVF and was more significant at posterior and central brain regions than that on frontal locations. As that the positive potential probably reflects the active inhibition activity in the brain during attention process, these data provide further evidence showing that the higher brain function was affected by the simulated weightlessness and that this effect was not only transient but also with interesting spatial characteristics.

Adult↗
PubMedDate not supplied

Molecular basis of Fas and cytochrome c pathways of apoptosis induced by tartary buckwheat flavonoid in HL-60 cells.

In a previous study, we showed that tartary buckwheat flavonoid (TBF) induced HL-60 leukemic cell apoptosis, most likely via a caspase 3 activating pathway. The aim of this study was to further investigate the molecular mechanisms involved in TBF-induced apoptosis of HL-60 cells. Thus, death receptor Fas expression on HL-60 cells was detected by flow cytometry (FCM). We also studied the effect of TBF on intranuclear DNA binding activity of NF-kappaB, as well as release of mitochondrial cytochrome c into the cytosol in HL-60 cells by FCM. The results suggest that TBF-induced apoptosis of HL-60 cells may be stimulated by the release of cytochrome c to the cytosol, upregulation of Fas expression on the cell surface, and through a caspase-3-dependent mechanism. Furthermore, TBF-induced apoptosis may be partly regulated through the inactivation of NF-kappaB in HL-60 cells. The induction of apoptosis by TBF may be attributed to its cancer chemopreventive activity.

Apoptosis↗
PubMedDate not supplied

Extract of Solanum muricatum (Pepino/CSG) inhibits tumor growth by inducing apoptosis.

BACKGROUND: Apoptosis, or programmed cell death, is characterized by certain distinct morphological and biochemical features. Most chemotherapeutic drugs exert their anti-tumor effects by inducing apoptosis. Therefore, an effective compound inducing apoptosis appears to be a relevant strategy to suppress various human tumors. In a search for tumor inhibitors from various kinds of plants, we found that extracts from Solanum muricatum (CSG) can inhibit tumor growth both in vivo and in vitro by inducing apoptosis. MATERIALS AND METHODS: A lyophilized aqueous fraction extracted from Solanum muricatum (CSG4) was used in this study. The human cell lines tested include: prostate (PC3, DU145), stomach (MKN45), liver (QGY-7721, SK-HEP-1), breast (MDA-MB-435), ovarian (OVCAR), colon (HT29) and lung (NCI-H209) cancer cells; NHP (prostate), HUVEC (umbilical vein endothelial cell), and WI-38 (lung diploid fibroblasts) normal cells. The cell survival was determined by either Cell Titer MTS cell proliferation kit or trypan blue dye exclusion assay. The apoptosis was analyzed by (a) apoptotic morphology by light microscopy; (b) DNA ladder formation; (c) PARP cleavage assay. RESULTS: a) CSG possesses selective cytotoxic activity against all the tumor cell lines being tested. The LD50 value is 561-825 micrograms/ml. b) CSG showed a much lower cytotoxicity to NHP, HUVEC and WI-38 normal cell lines with LD50 value being 2.8-3.2 mg/ml, which is 3-6 fold higher than on tumor cells. c) The in vivo study demonstrated that injection of CSG (100 micrograms) directly into tumor mass can reduce the tumor volume dramatically in nude mice inoculated with MKN45 gastric cancer cells. d) CSG-mediated tumor growth inhibition is through induction of apoptotic cell death, as manifested by (a) typical apoptotic morphology; (b) DNA ladder formation; and (c) PARP cleavage assay. CONCLUSION: Taken together, the present study suggests, for the first time, that CSG may represent promising new chemical entity which preferentially targets various tumor cells by triggering apoptosis.

Animals↗