Search PubMed⌕ Search

Biomedical subjects

S F Zhang

Publications and source records attributed to S F Zhang.

At least 37 records · Page 2Linked to original sources
PubMed1994

Stimulation of human osteoblast differentiation and function by ipriflavone and its metabolites.

Ipriflavone (IP), an isoflavone derivative, has been shown to interfere with bone remodeling by inhibiting bone resorption and perhaps stimulating bone formation. In this study, we have analyzed the effect of IP and its metabolites on the differentiation and function of human osteoblastic cells. Bone marrow stromal osteoprogenitor cells (BMC) and trabecular bone osteoblasts (HOB) were isolated from human donors. The former can be induced to differentiate by treatment with dexamethasone, whereas the latter represent a more differentiated osteoblast. Incubation of BMC with metabolite III (10(-5) M) for 1 week induced modest but significant changes of alkaline phosphatase activity. Though both IP and metabolite III stimulated the expression of bone sialoprotein mRNA, a protein involved in cell attachment to the matrix, only metabolite III increased the steady-state level of decorin mRNA, a collagen fibrillogenesis-regulating proteoglycan. Metabolites III and V, but not the other isoflavones, increased the expression of type I collagen mRNA in HOB, whereas no detectable changes were observed in BMC cells with any of the experimental compounds. In HOB, an increased abundance of osteopontin and bone sialoprotein mRNA were also obtained after 1-week treatment with IP or metabolite V. No appreciable effects of IP or its metabolites were seen on osteocalcin expression and synthesis by either cell type. Finally, IP consistently increased the amount of 45Ca incorporated into the cell layer by BMC, and stimulated mineralization of both BMC and HOB, assessed by von Kossa staining. Thus, IP and its metabolites regulate the differentiation and biosynthetic properties of human bone-forming cells by enhancing the expression of some important matrix proteins and facilitating the mineralization process.

Alkaline Phosphatase↗
PubMed1994

Differentiation of human bone marrow osteogenic stromal cells in vitro: induction of the osteoblast phenotype by dexamethasone.

Human bone marrow stromal cells were examined for their osteogenic potential in an in vitro cell culture system. Dexamethasone (Dex) treatment induced morphological transformation of these cells from an elongated to a more cuboidal shape, increased their alkaline phosphatase activity and cAMP responses to PTH and prostaglandin E2, and was essential for mineralization of the extracellular matrix. Dex-induced differentiation of human bone marrow stromal cells was apparent after 2-3 days of treatment and reached a maximum at 7-14 days, as judged by alkaline phosphatase activity, although induction of osteocalcin by 1,25-dihydroxyvitamin D3 was attenuated by Dex. Withdrawal of Dex resulted in an enhancement of the 1,25-dihydroxyvitamin D3-induced secretion of osteocalcin, whereas alkaline phosphatase activity and the cAMP response to PTH remained at prewithdrawal levels. The steady state mRNA level of osteonectin was not affected by Dex. Our results, which demonstrate that Dex conditions the differentiation of human bone marrow osteogenic stromal cells into osteoblast-like cells, support the hypothesis of a permissive effect of glucocorticoids in ensuring an adequate supply of mature osteoblast populations. Furthermore, the established human bone marrow stromal cell culture provides a good model of an in vitro system to study the regulation of differentiation of human bone osteoprogenitor cells.

Adult↗
PubMed1994

The effect of glucocorticoid on the synthesis of biglycan and decorin in human osteoblasts and bone marrow stromal cells.

We have previously demonstrated that glucocorticoids induce differentiation of human bone marrow stromal cells (BMSC) into cells expressing mature osteoblast phenotype. As glucocorticoids have marked effects on extracellular matrix protein synthesis in bone, and because proteoglycans are important components of bone matrix and may condition the differentiation and biological activities of osteoblasts, we studied the effects of dexamethasone (Dex) on the synthesis of small proteoglycans [decorin (DCN) and biglycan (BGN)] in adult human BMSC and human osteoblasts (HOB). First passaged HOB and BMSC were treated with either ethanol or 10(-7) M Dex for 7 days. After treatment, the cells were metabolically labeled with either [35S]SO4 alone or [35S]SO4 and [3H]leucine together for 24 h. Conditioned media were collected, and cell layers were extracted with 4 M guanidine HCl. The extracts and conditioned media were subjected to gel filtration and ion exchange chromatography. Fractions containing radiolabeled proteoglycans were analyzed either directly or after immunoprecipitation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Dex treatment resulted in a dramatic increase in DCN and an associated decrease in BGN in both the conditioned medium and the cell layer of HOB cultures. In Dex-treated BMSC cultures, BGN was decreased in both the conditioned medium and cell layer, whereas DCN was stimulated in the majority of cultures. Northern blot analysis indicated that steady state messenger RNA (mRNA) concentration of DCN was increased by Dex in all of the HOB cultures and in seven of eight BMSC cultures analyzed. The steady state mRNA level of BGN was decreased by Dex in both HOB and BMSC cultures. The regulation of DCN and BGN mRNA by Dex in both HOB and BMSC (when responsive) was dose dependent. Time-course analysis indicated that as little as 1 day of treatment with Dex was sufficient to decrease BGN mRNA and increase DCN mRNA (when observed) levels in BMSC; the regulation spanned a 4-week interval, during which the extracellular matrix of BMSC was mineralized. The effect of Dex on the steady state mRNA levels of DCN and BGN in HOB was also apparent after 1 day of treatment. These accumulated results suggest that Dex modulates the synthesis of small proteoglycans in both human bone marrow stromal osteoprogenitor cells and mature osteoblasts.

Biglycan↗
PubMed1994

[A clinical analysis of pupillary membrane formation after intraocular lens implantation].

In 540 cases having undertaken extracapsular cataract extraction and intraocular lens implantation, a pupillary membrane developed in 76 cases, the rate of occurrence being 14%. Generally, the membrane appears on the fifth post-operative day and corticosteroids are effective in its treatment. After treatment no significant sequela is left and the corrected postoperative visual acuity is not affected. The pathogenesis, treatment and prognosis of the pupillary membrane are briefly discussed in the report.

Adolescent↗
PubMed1994

[Infection of acid-fast bacterial L-forms].

One hundred and fifty five cases which pathological diagnosis were chronic lymphadenitis were studied in order to detect infection of acid-fast bacterial L-forms by Ziehl-Neelsen (ZN), intensified kinyoun (IK) and immunohistochemical staining (PAP). The results showed that the expression of M-tuberculosis antibody was positive in 106 cases (68.4%). Among them, 94 cases (60.6%) were positive in IK staining. The positive rate of acid-fast bacillus was 0.6% (1 case), of L-forms was 60% (93 cases). L-forms are higher pleomorphic, spherical bodies, giant bodies or long filaments were shown. The L-forms mostly localised within macrophages, only a few distributed sporadically. The possible causes of misdiagnosis physician and pathologist were discussed. The prognostic value was also suggested.

Antibodies, Bacterial↗
PubMed1994

[Clinicopathologic changes in leukemic lung lesions].

Leukemic lung lesions are complex and various. The authors studied the clinicopathologic changes in 104 autopsied leukemic cases collected from 1953 to 1990. 22.1% of the cases had the symptoms of respiratory tract admission and 40.4% developed the symptoms before death. 12.8% of the patients were diagnosed with X-ray to have tuberculosis and infections on admission and 42% cases have these changes in the terminal phase. The main pathological changes are pleural effusion, pleural adhesion, intrapulmonary infections, hemorrhage and Myleran lung. The rate of leukemic cell infiltration in lungs was 96.2% and the infiltration was mainly interstitial. Intravascular leukemic cell stasis was found in 91.3% of the cases. The pathological changes in each case were usually multiple and 84.6% of the cases had more than two kinds of changes. We compared the X-ray diagnoses with pathological ones and it was shown that complete coincidence was present only in 2.9%, partial coincidence in 58.8% and no coincidence in 38.3% of the cases.

Adolescent↗
PubMed1993

[Localization and significance of lysozyme in tuberculosis].

The relationship between expression of lysozyme and tuberculosis lesions was studied in 132 patients. The positive rate of lysozyme expression in 132 tuberculosis cases was 83.3%. Lysozyme was mainly distributed intracellularly, and the positive rates in different types, i.e. in cases with lesions of caseous necrosis, cellular nodes, and fibroid nodes were 90.1%, 79.3% and 63.3% respectively (P < 0.05 between lesions of caseous necrosis and fibroid nodes). The positive rate of lysozyme in cases of infection associated with L-form tubercule bacillus was 64.4%, which was higher in cases with positive L-form antigen than that in antigen negative cases (P < 0.025). The results indicated that expression of lysozyme was rather active, and might be considered as a marker for the prognosis of tuberculosis treatment.

Biomarkers↗
PubMed1992

[Investigation of interleukin 2 receptor and T cell subsets in the patients with tuberculous meningitis].

Interleukin 2 receptor (IL-2R) on lymphocyte and T cell subsets of peripheral blood(PB), defined by monoclonal antibodies, were studied in 25 patients with tuberculous meningitis. 25 staff members served as PB control. Dynamic changes of IL-2R positive cells and T cell subsets were observed in 10 of 25 patients at sixth week after chemotherapy. IL-2R positive cells showed higher percentages in the patients than in healthy controls. Percentages of CD5and CD4cells were lower than those of healthy control. With chemotherapy, the percentages of CD4cells raised. The results indicated that M. tuberculosis might stimulate T cell to express IL-2R. A lower cell mediated immunity function in the patients with tuberculous meningitis was characterized by CD4 lymphopenia.

Adult↗
PubMed1992

[A clinicopathological study of leukemic kidney].

A clinicopathological study of leukemic kidney was carried out by observing the changes of the kidney in 104 autopsied cases of leukemia. The main changes of the leukemic kidney were increase of renal weight, calcinosis of renal tubules, interstitial leukemic cell infiltration, intravascular stasis and renal bleeding. Calcinosis intravascular stasis, renal bleeding as well as hyperuricemia may lead to abnormal urinary findings. The presence and severity of interstitial infiltration have no obvious relation with the level of blood urea nitrogen, creatinine and muric acid as well as the abnormal change of the urine. However, the presence of intravascular stasis by leukemic cells are correlated with the disturbance of renal function.

Adolescent↗
PubMed1992

[The analysis of the maxillary complete denture and its underlying supporting tissues with three dimensional finite element method under the vertical occlusal force in centric occlusion].

A 3-dimensional finite element method was employed in this study to investigate the stress and displacement states of the maxillary complete denture and its underlying supporting tissues under the vertical occlusal force in centric occlusion. The calculation results show that the harmful transverse tension stresses within the base are concentrated on the maxillary incisor regions and its palatal area near the polishing surface. Pressure is exerted over most of the area of the jaw bone cortical surface and the compression stress is strongly concentrated over the alveolar ridge. The posterior palatal area of the denture base migrates away from the mucosa membrane and the other parts press the underlying tissues. These results indicate the biomechanical mechanism of the maxillary denture fracture and alveolar ridge resorption.

Alveolar Process↗
PubMed1991

Insect resistance of transgenic tobacco plants expressing delta-endotoxin gene of Bacillus thuringiensis.

The initiative B.thuringiensis delta-endotoxin (Bt toxin) gene clones TH12 and TH48 contain two different classes of homologous genes, the 5.3 kb class and 6.6 kb class, respectively. Bt toxin genes of both classes, modified at the 5'-end and truncated at the 3'-end, can still be expressed to produce the insecticidal, truncated toxin proteins in E. coli. The modified Bt toxin genes were inserted into the plant binary expression vector pBin 437 (a derivative plasmid of pBin 19) and were transferred into tobacco by Ti plasmid-mediated gene transfer system. Southern blot and DNA slot blot analysis indicate that the Bt toxin genes have been integrated into tobacco genome at a copy number of 1 to 5. Northern blot analysis of polyA+ RNAs from progeny of the transgenic plants revealed that Bt toxin genes of both 5.3 kb and 6.6 kb classes were expressed in transgenic plants, though the transcripts were degraded to RNAs of lower molecular weights. In insecticidal test, 5 plants from the progeny of 5.3 kb class gene-transformed SR1 tobacco plants and 3 plants from those of 6.6 kb class gene-transformed plants were found to be toxic to the testing larvea of H.assulta. In comparison with the control, mortality of the insects fed on transgenic plants reached 40-50% and the growth of the survived insects was remarkably inhibited. These results indicate that the modified Bt genes of the 5.3 kb and 6.6 kb classes were expressed in transgenic plants and could confer on the transgenic plants a new character of insect resistance.

Animals↗
PubMed1991

[Effects of antihypertensive factor from erythrocytes of essential hypertensive subjects on blood pressure in rats].

The effects of antihypertensive factor (AHF) from erythrocytes of essential hypertensive human subjects on the systolic blood pressure (SBP) and diastolic blood pressure (DBP) in spontaneously hypertensive rats (SHR), renal hypertensive rats (RHR), Wistar-Kyoto rats (WKY) and Wistar rats were examined. Single intraperitoneal injection of AHF (1.6 mg/kg body weight) resulted in a significant decrease in SBP of SHR and RHR. At 10 min postinjection, AHF lowered the SBP in SHR by 34.0 mmHg. SBP recovered to the original level at 3 h. The maximal decrease of SBP in RHR by 92.5 mmHg was at 24h postadministration and the SBP did not recover until the 9th day. When AHF was administered via femoral vein (0.8 mg/kg body weight), the maximal decrease values of the SBP and the DBP were 42.8 and 48.2 mmHg in SHR at 12 min and 38.3 and 42.5 mmHg in RHR at 25 min postinjection respectively. The DBP in Wistar rats decreased considerably (from 96.7 +/- 12.9 to 83.3 +/- 11.7 mmHg) at 5 min postadministration of AHF, but no effect on DBP in WKY rats was observed. The depressor effect of AHF on SBP in RHR was dose-dependent. AHF could also antagonize the pressor effect of norepinephrine in Wistar rats.

Aged↗
PubMed1991

Effects of antihypertensive factor from erythrocyte of spontaneously hypertensive rats on the blood pressure and Ca2+ influx of arterial smooth muscle in rats.

The effects of a partially purified antihypertensive factor (AHF) from erythrocytes of spontaneously hypertensive rats (SHR) on the blood pressure (BP) and Ca2+ influx of vascular smooth muscle (VSM) in rats were studied. The results indicated that AHF could produce a marked prolonged depressor effect and significantly inhibit the Ca2+ influx dose-dependently on both SHR and renal hypertensive rat (RHR) either in acute or in chronic experiments, but not on normotensive rats. It suggested that the inhibition of Ca2+ influx might be one of the important mechanisms for AHF as an endogenous depressor substance.

Animals↗
PubMed1989

Corticofugal influences on the responses of bat inferior collicular neurons to sound stimulation.

Corticofugal influences on the responses of inferior collicular neurons (IC) to acoustic stimulation were studied by electrical stimulation of the auditory cortex. Among 471 IC neurons isolated, about 26% were affected by cortical stimulation. Responses of 103 (22%) IC neurons were inhibited and 17 (3.6%) were facilitated. The degree of inhibition was dependent upon the amplitude of both auditory and electrical stimuli. Corticofugal inhibition of the response of an IC neuron was likely due to an increase in the neuron's minimum threshold. Inhibitory latency varied with the interstimulus interval. The shortest inhibitory latency of most IC neurons was between 1 and 2 ms. The localization of the point of cortical stimulation was crucial in determining the responses of IC neurons. It is assumed that corticofugal influences on IC neurons are a part of regulatory mechanism in the centrifugal pathway for frequency analysis and acoustic orientation.

Acoustic Stimulation↗