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L Hong

Publications and source records attributed to L Hong.

106 records · Page 6Linked to original sources
PubMed1992

Tensile strength of the interface between hydroxyapatite and bone.

Tensile strength of the interface between hydroxyapatite (HA) and bone was tested. Scanning electron microscopy was used to observe the tensile failure mode and the morphological change of hydroxyapatite ceramic surface in bone. The porosity of hydroxyapatite is 14% and pore size less than 2 microns. After 2 weeks of implantation, the tensile strength of the interface is 0.72 MPa. After 4, 8, and 16 weeks, the average tensile strength stayed at 1.5 MPa. SEM showed that tensile failure occurred at the HA-bone interface at the second week, but after 4 weeks, the failure occurred between HA particles within the bulk, and not at the HA-bone interface. Calcified tissue was directly deposited on the HA ceramic surface and exits also in the micropores. Near the interface, sintered necks among HA ceramic particles were subjected to biodegradation.

Animals↗
PubMed1992

Loss of collagen type VI from rat endometrial stroma during decidualization.

The expression of collagen type VI in the extracellular matrix of rat uterine endometrial stroma after a decidual stimulus was examined by immunolocalization and immunoblotting. The intermediate filament protein, desmin, was used as a marker to identify decidual cells. Tissue was examined from pregnant animals and from ovariectomized, hormone-treated rats in which decidualization had been induced artificially. In undifferentiated tissue from both groups of animals, collagen type VI was abundant, and desmin was present only in vascular smooth muscle cells. By 72 h after a decidual stimulus, however, collagen type VI had essentially disappeared from the matrix of the antimesometrial stromal compartment, and desmin was highly expressed in the decidualizing cells. During regression of the decidual tissue, collagen type VI began to reappear in the stromal matrix, whereas desmin expression declined as decidual cells degenerated. These results indicate that remodeling of the uterine extracellular matrix in response to embryo implantation is a function of the differentiating decidual cell.

Animals↗
PubMed1992

Somnogenic, pyrogenic, and anorectic activities of tumor necrosis factor-alpha and TNF-alpha fragments.

Exogenously administered tumor necrosis factor-alpha (TNF-alpha) elicits several symptoms of generalized infections such as fever, increased sleep, and anorexia. The aim of the present work was to localize these effects of TNF-alpha to specific amino acid sequences of the parent molecule by characterizing the in vivo and in vitro activities of several synthetic TNF-alpha fragments. Intracerebroventricular injection of TNF-alpha elicited dose-dependent fevers and increases in non-rapid-eye-movement sleep (NREMS) in rabbits. Four fragments also promoted NREMS and five elicited monophasic fevers. All of the somnogenic fragments share the amino acid sequence 31-36. In rats, TNF-alpha and one of the fragments [TNF-alpha-(69-100)] suppressed 12-h food intake. Furthermore, TNF-alpha increased the expression of the intercellular adhesion molecule-1 and enhanced interferon-gamma-induced HLA-DR expression in human glioblastoma cell line. In contrast, none of the fragments possessed these in vitro activities. Our in vivo results support the concept that there are biologically active regions in the TNF-alpha molecule.

Animals↗
PubMed1991

Developmental expression of adenosine deaminase during decidualization in the rat uterus.

Adenosine deaminase (ADA) is expressed in high concentrations at the fetal-maternal interface during postimplantation stages of gestation in the mouse. The experiments reported here were designed to identify the specific uterine cells that express ADA subsequent to implantation in the rat and to determine if embryonic cells contribute to ADA expression. The results of biochemical analysis demonstrate that ADA-specific activity increases to very high levels in implantation sites, beginning approximately 72 h after blastocyst attachment. Immunocytochemical analysis localized this ADA expression to the decidualized stromal cells in the antimesometrial region of the pregnant uterus. In experimentally induced deciduoma, these cells were capable of synthesizing high levels of both ADA and mRNA for ADA in the absence of embryos. The enzyme first appeared in decidual cell cytoplasm, approximately 72 h after induction of decidualization, and later was localized in the decidual cell nuclei. Since the expression of ADA and its mRNA in decidual cells follows the appearance of desmin, a protein marker for decidualization, by at least 48 h, ADA appears to be involved in the functioning of mature decidual cells rather than in stromal cell differentiation. The expression of ADA, but not desmin, was restricted to the antimesometrial decidual cells and decreased when these cells regressed. At mid-gestation ADA activity increased and was localized principally in the fetal placenta. The results presented here demonstrate that ADA is localized to the antimesometrial decidual cell and that its expression is consequent to differentiation of the uterine stromal cell and independent of any embryonic stimulus.

Adenosine Deaminase↗
PubMed1991

[Determination of panaxadiol and panaxatriol in radix notoginseng and Yunnan baiyao by capillary supercritical fluid chromatography].

Capillary supercritical fluid chromatography (SFC) was developed for the determination of panaxadiol and panaxatriol in Radix notoginseng and Yunnan baiyao. 0.1g Radix notoginseng powder or 0.5g Yunnan baiyao was mixed with 10 ml 15% H2SO4 ethanol-water (1:1) solution, adding 1 mg cholesterol as internal standard. The mixture was refluxed for 4 h, then adding 15 ml 15% NaOH solution, refluxed for 0.5 h. The mixture was extracted 3 times with 10 ml portions of cyclohexane. The cyclohexane extracts were purified by partition column and concentrated by adsorption column and then analysed by SFC. The proposed method is sensitive, accurate, precise, simple and rapid; all the process can be done in 8 h.

Chromatography↗
PubMed1991

[Primary study of condylo-pterygomaxillo-oblique projection in CT and magnetic resonance images].

The literature is reviewed that we have not yet seen in the TMJ examination by X-ray, CT and MR associated with the study of lateral pterygoid muscle simultaneously. In this paper we observed the CT and MR images of condylo-pterygo-maxillo-oblique projection (the origin and insertion plane of the lateral pterygoid muscle), In which we can see the relationship between TMJ structures and lateral pterygoid muscle under different functional states clearly. All of the X-ray, CT and MR images were compared with each other for clinical reference.

Humans↗
PubMed1991

[The contrivable purpose and anatomical foundation of condylo-pterygo-maxillo-oblique tomography].

It is obvious that the Schüller's position of X-ray film is not enough to examine the TMJ, because it is limited in anterior and posterior view of the joint. The CPMO tomograph contrived by the authors can demonstrate the external and internal view of the joint and the surrounding structures of the joint, particularly the external pterygoid muscle. Therefore, it would be a complement to the Schüller's position. Under cross reference of these two films, the whole view of the TMJ, the joint external pterygoid muscle, and the relationship of the occlusion could be seen in one film. Certainly, this discovery will be of great value in the diagnosis and treatment of the TMJ diseases. In this paper the data of the anatomical measurement of 30 skulls are introduced. According to the results, the best angle of the film plane and projection to the sagittal middle line of the cranial is 45 degrees. Some other angles of projection for the TMJ examination are compared and discussed.

Cephalometry↗
PubMed1986

Alterations in bone marrow cell cycle kinetics by diphenylhydantoin and folate deficiency are restored by thymic peptides.

We have previously shown that the anticonvulsant drug, diphenylhydantoin (DPH), causes impaired humoral immunity and host resistance in subchronically treated mice as a consequence of myelotoxicity. The bone marrow is a primary and sensitive target for this drug, which causes a selective loss of stem cells in S phase. The present report describes the restoration of stem cell kinetics by thymosin in both drug-treated and folate-deficient mice. Thymosin and the thymic peptide, FTS (facteur thymique serique), were also able to protect the progenitor stem cell, CFU-GM, from DPH inhibition in vitro, indicating a direct effect of both drug and thymic factors on stem cells. Although the mechanism of this protection is not yet understood, the observation may have important implications concerning immunotherapy of DPH-treated epileptics, who are at increased risk of infectious diseases and malignancies.

Animals↗
PubMed1985

Alteration of bone marrow cell cycle kinetics by diphenylhydantoin: relationship to folate utilization and immune function.

Female B6C3F1 mice were administered the anticonvulsant drug diphenylhydantoin (DPH) for 1 to 4 weeks by gavage at doses of 25 to 200 mg/kg. None of the dosing regimens caused toxicological manifestations other than hepatomegaly. Evaluation of the immune status of the drug-treated mice revealed no alteration of cellular immunity, measured by delayed hypersensitivity response and lymphocyte responsiveness to mitogens or allogeneic leukocytes. Humoral immunity, as measured by serum immunoglobulin quantitation and plaque-forming cell response to sheep erythrocytes, was depressed by DPH at 100 mg/kg after 2 weeks, as was host resistance to infection with the parasite Plasmodium yoelii. The bone marrow was the most sensitive target organ with loss of the multipotent stem cell colony-forming unit-spleen occurring within 1 week at a dose of 50 mg/kg. The colony-forming unit-spleen suppression was the result of a selective loss of stem cells in S phase. Committed granulocyte macrophage progenitor cells, colony-forming unit-granulocyte macrophage, were also inhibited by DPH in vivo, as well as in vitro at concentrations as low as 0.2 microM. Bone marrow cells from DPH-treated mice were folate deficient, as determined by the inability of these cells to convert deoxyuridine to thymidine. However, these mice had normal serum folate levels, even after 4 weeks of treatment. Folic acid protected bone marrow stem cells after both in vivo and in vitro treatment with DPH. It is suggested that DPH inhibits folate utilization or metabolism at the cellular level, selectively affecting bone marrow stem cells and resulting in altered stem cell kinetics. This lesion ultimately results in altered humoral immunity and impaired host resistance.

Animals↗
PubMed1984

Mechanisms of estrogen-induced myelotoxicity: evidence of thymic regulation.

Mice exposed to pharmacological levels of steroidal and nonsteroidal estrogens including alpha-dienestrol, 17 beta-estradiol, and diethylstilbestrol demonstrate bone marrow hypocellularity, and decreased numbers of pluipotent hemopoietic stem cells. Hormones with little estrogenic activity including testosterone and progesterone failed to induce myelotoxicity as did nonestrogenic metabolites of DES. Myelotoxicity associated with estrogen exposure is regulated by a complex bimodal mechanism. One of these mechanisms is mediated through the thymus since surgical thymectomy abolished the ability of estrogens to suppress CFU proliferation. Furthermore, supernatants of thymic epithelial cells cultured in the presence of estradiol were capable of inhibiting CFU-GM colony formation. Specific myelotoxic events can also be disassociated chemically by testing weakly estrogenic compounds such as zearalanol which shows different sensitivity on cytoxic and antiproliferative events. Myelotoxicity is not mediated indirectly through the ovary or adrenal gland. That the initial events in estrogen-induced myelotoxicity may be mediated through a receptor mechanism was suggested by the ability of antiestrogens to induce antagonism when administered prior to estradiol and the presence of estrogen binding components in lymphoreticular tissues including the thymus and bone marrow. These studies suggest that reduced CFU kinetics observed following estrogen exposure is, in part, due to alterations in regulatory factors produced by thymic epithelial cells in response to a specific estrogen stimulus. Estrogens may also influence bone marrow functions through non-thymic mechanisms at higher dose levels.

Animals↗
PubMedDate not supplied

Determination of panaxadiol and panaxatriol in ginseng and its preparations by capillary supercritical fluid chromatography (SFC).

Capillary supercritical fluid chromatographic (SFC) method has been developed for the determination of panaxadiol and panaxatriol in ginseng and its preparations. 0.1 g ginseng or an appropriate amount of its preparations was hydrolysed by 15% H2SO4 in an ethanol:water (1:1 v/v) solution for 4 h followed by 15% NaOH for 0.5 h. The mixture was extracted by cyclohexane. The cyclohexane extracts were purified by a partition column and concentrated by an adsorption column and then analysed by SFC. Methyltestosterone was used as the internal standard.

Chromatography↗
PubMedDate not supplied

Underlying personality differences between alcohol/substance-use disorder patients with and without an affective disorder.

The Myers-Briggs Type Indicator (MBTI), a popular personality test, was used to profile the personalities of in-patient alcoholics/substance-use disorder patients who had, and those who did not have, a concurrent affective disorder diagnosis. The MBTI divides individuals into eight categories: Extroverts and Introverts, Sensors and Intuitives, Thinkers and Feelers, and Judgers and Perceivers. Alcohol/substance-use disorder patients with no affective disorder differed from a normative population only in being significantly more often Sensing and significantly less often Intuitive single-factor types. The Extroverted/Sensing/ Feeling/Judging four-factor type was also significantly over-represented in this group, compared to a normative population. In contrast, mood-disordered alcohol/substance-use disorder patients were significantly more often Introverted, Sensing, Feeling, and Perceiving and significantly less often Extroverted, Intuitive, Thinking, and Judging single-factor types. They were also significantly more often Introverted/Sensing/ Feeling/Perceiving and Introverted/Intuitive/Feeling/Perceiving four-factor types. 'Pure' alcohol/ substance-use disorder patients differed from alcohol/substance-use disorder patients with a mood disorder in that they were significantly more often Extroverted and Thinking and significantly less often Introverted and Feeling single-factor types; and significantly less often were an Introverted/Sensing/ Feeling/Perceiving four-factor type. The above results may have psychogenetic, diagnostic, and psychotherapeutic implications.

Adult↗