Biomedical subjects

Jianhong Liu

Publications and source records attributed to Jianhong Liu.

13 recordsLinked to original sources

PubMed2007

Developing comparative criminology and the case of China: an introduction.

Although comparative criminology has made significant development during the past decade or so, systematic empirical research has only developed along a few topics. Comparative criminology has never occupied a central position in criminology. This article analyzes the major theoretical and methodological impediments in the development of comparative criminology. It stresses a need to shift methodology from a conventional primary approach that uses the nation as the unit of analysis to an in-depth case study method as a primary methodological approach. The article maintains that case study method can overcome the limitation of its descriptive tradition and become a promising methodological approach for comparative criminology.

China↗

PubMed2006

Substituted N-(2-aminophenyl)-benzamides, (E)-N-(2-aminophenyl)-acrylamides and their analogues: novel classes of histone deacetylase inhibitors.

Inhibition of histone deacetylases (HDACs) is emerging as a new strategy in human cancer therapy. Novel 2-aminophenyl benzamides and acrylamides, that can inhibit human HDAC enzymes and induce hyperacetylation of histones in human cancer cells, have been designed and synthesized. These compounds selectively inhibit proliferation and cause cell cycle arrest in various human cancer cells but not in normal cells. The growth inhibition of 2-aminophenyl benzamides and acrylamides against human cancer cells in vitro is reversible and is dependent on the induction of histone acetylation. Compounds of this class can significantly reduce tumor growth in human tumor xenograft models.

Acrylamides↗

PubMed2006

Odontogenic keratocysts arise from quiescent epithelial rests and are associated with deregulated hedgehog signaling in mice and humans.

Odontogenic keratocysts in humans are aggressive, noninflammatory jaw cysts that may harbor PTCH1 mutations, leading to constitutive activity of the embryonic Hedgehog (Hh) signaling pathway. We show here that epithelial expression of the Hh transcriptional effector Gli2 is sufficient for highly penetrant keratocyst development in transgenic mice. Mouse and human keratocysts expressed similar markers, leading to tooth misalignment, bone remodeling, and craniofacial abnormalities. We detected Hh target gene expression in epithelial cells lining keratocysts from both species, implicating deregulated Hh signaling in their development. Most mouse keratocysts arose from rests of Malassez--quiescent, residual embryonic epithelial cells that remain embedded in the periodontal ligament surrounding mature teeth. In Gli2-expressing mice, these rests were stimulated to proliferate, stratify, and form a differentiated squamous epithelium. The frequent development of keratocysts in Gli2-expressing mice supports the idea that GLI transcription factor activity mediates pathological responses to deregulated Hh signaling in humans. Moreover, Gli2-mediated reactivation of quiescent epithelial rests to form keratocysts indicates that these cells retain the capacity to function as progenitor cells on activation by an appropriate developmental signal.

Animals↗

PubMed2005

Studies on the mechanism of Indigo Carmine removal by solvent sublation.

Indigo Carmine (C16H8N2Na2O8S2), an anionic dye, was removed from aqueous solution by solvent sublation of Indigo Carmine-cetyltrimethylammonium bromide (CTAB) complex (sublate) into 2-octanol. A stoichiometric amount of surfactant (surfactant:dye=2:1) was demonstrated to be able to remove over 93% IC from the aqueous solution in 5 min. The apparent activation energy of attachment of the sublate to bubbles was calculated as 1.3 kJ/mol. Parameters were considered. At the same time, on the base of the complete transport mechanism, a mathematical model for the dye-surfactant complexation was obtained. Furthermore, the simulation of the mathematical and experimental data was made with good results.

Journal Article↗

PubMed2005

Release of theophylline from polymer blend hydrogels.

Polymer blending is a simple yet attractive method to obtain combined physical and mechanical properties of polymers. In this paper, three types of blend hydrogels were prepared, each by physically blending two different natural polymers, and a model drug, theophylline (TPH), was immobilized into these hydrogels for the studies of drug release. The release profiles of TPH from various types of hydrogels were determined by UV-vis absorption measurement at 272 nm. The experimental results show that the releases of TPH from these hydrogels are dependent upon the composition of the hydrogel, the type of component, the possible interactions between two component polymers, as well as external temperature. All the release profiles clearly demonstrate a temperature effect. Among the three blend hydrogels, the slowest release was observed from the blend hydrogel of gelatin and agar with a weight ratio of 1:1. The drug release patterns and release mechanisms have been discussed by considering the possible molecular interactions and gel network structures.

Carrageenan↗

PubMed2005

SDS-aided immobilization and controlled release of camptothecin from agarose hydrogel.

Camptothecin (CPT), known to be an effective anticancer drug, has a limited therapeutic utility because of its poor water solubility. In this work, an approach has been made to overcome the limitation. CPT was first incorporated into the micelles formed from an ionic surfactant, sodium dodecyl sulfate (SDS) and the micellar drug aqueous solution was then used in preparation of the agarose hydrogel. It has been found that the presence of SDS greatly increased the solubility of CPT in water. For example, in 1 ml of 1.0 wt.% SDS water solution, 0.11 mg CPT could be solubilized (0.318 mM), which was 83 times the solubility in pure water. It was the hydrophobic cores of the SDS micelles that were able to accept the lipophilic drug to form stable drug-immobilized micelles. The formulation of a hydrogel using the drug-immobilized micelles has allowed us to obtain a unique and novel drug release system where the drug molecules are encapsulated by the micelles and the drug-containing micelles are dispersed in the gel network. The release of CPT from the so deliberately fabricated agarose hydrogel system has been studied as a function of surfactant concentration at 37 degrees C. The diffusion coefficients of CPT obtained by fitting to Fick's law ranged from 2.12 to 7.36 x 10(-7)cm(2)s(-1). The results showed that SDS prolonged the drug release by reducing the diffusion coefficient of CPT in the gel.

Antineoplastic Agents, Phytogenic↗

PubMed2005

The removal of humic acids from water by solvent sublation.

The application of solvent sublation in the removal of humic acids was investigated in the present study. The humic acids (HA) were removed from an aqueous solution by solvent sublation of humic acid-hexadecylpyridium chloride (HPC) complex (sublate) into isopentanol. Several parameters were examined towards the optimization of humic acid removal; the dosage of a surfactant was found to be the major one, controlling the overall efficiency of the progress. The removal rate was somewhat enhanced by higher airflow rate and almost independent of the volume of the organic solvent floating on the top of the aqueous column. The effects of electrolytes (e.g., NaCl), nonhydrophobic organics (e.g., ethanol), and pH of the solution upon the process were studied. Under the optimized condition, the treatment performance was found to be very efficient, reaching almost 100%, indicating that solvent sublation can serve as a possible alternative technology for the removal of humic acids. The solvent sublation process follows first-order kinetics. A characteristic parameter, apparent activation energy of attachment of the sublate to bubbles, was estimated at a value of 9.48 kJ/mol. Furthermore, the simulation of a mathematical model with the experiments on the solvent sublation of humic acid-HPC was described here.

Letter↗

PubMed2005

Predicting recidivism in a communitarian society: China.

Research on the prediction of recidivism has largely been an enterprise of Western criminology. Therefore, the identification and selection of predictors has tended to follow the individualistic traditions of the West. Important advances in models and methods have not been extended to non-Western societies such as China. This article explores the implications of communitarian features of Chinese urban communities for prediction of recidivism. The article applies the perspective of social capital to the specification of predictors. Available community social-capital measures are included in the prediction model to capture the effects of communitarian cultural features. The results indicate that social capital variables generally have significant effects.

Adolescent↗

PubMed2005

[Population dynamics of Bactrocera dorsalis (Diptera: Tephritidae) in Xishuangbanna of Southern Yunnan].

In the study, an all year round monitoring through lure-traps in 1997, 2000 and 2003 was conducted on the population dynamics of oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae) in Xishuangbanna of Southern Yunnan, and the factors in relation with its population fluctuation, including temperature, rainfall, and host species were analyzed. The fruit fly occurred year-round in Xishuangbanna, with a low population level from November to February, and increased steadily from March to July or August. An increasing peak appeared in July or August, depending on the rainfall amount in that year. Afterwards, the fly population declined markedly until to October. Temperature, rainfall, and host fruits were supposed to be the major factors affecting the population fluctuation. The monthly average temperature in Xishuangbanna was in the ranges suitable for the development and reproduction of the fly, but the monthly average minimum temperature from December to February appeared to be lower than the suitable temperature, which was suggested to be responsible for the low populations in the winter months. Rainfall was another essential factor affecting population fluctuation. The population was depressed when the monthly rainfall amount was lower than 50 mm, but increased when the amount ranged between 100 and 200 mm. Under conditions the monthly rainfall amount was higher than 250 mm, the fruit fly population was reduced markedly, which explained the decreasing population in July or August when the heavy rain occurred. Mango, orange, pear, longan, and peach were the main host species of the fly, among which, mango and longan were most preferred by the fly. Therefore, their planted area, fruiting period and productivity exerted essential effects on the fly population fluctuation, and regarded as another major factor affecting the fly population in this area.

Animals↗

PubMed2004

Sustained Hedgehog signaling is required for basal cell carcinoma proliferation and survival: conditional skin tumorigenesis recapitulates the hair growth cycle.

Temporally and spatially constrained Hedgehog (Hh) signaling regulates cyclic growth of hair follicle epithelium while constitutive Hh signaling drives the development of basal cell carcinomas (BCCs), the most common cancers in humans. Using mice engineered to conditionally express the Hh effector Gli2, we show that continued Hh signaling is required for growth of established BCCs. Transgene inactivation led to BCC regression accompanied by reduced tumor cell proliferation and increased apoptosis, leaving behind a small subset of nonproliferative cells that could form tumors upon transgene reactivation. Nearly all BCCs arose from hair follicles, which harbor cutaneous epithelial stem cells, and reconstitution of regressing tumor cells with an inductive mesenchyme led to multilineage differentiation and hair follicle formation. Our data reveal that continued Hh signaling is required for proliferation and survival of established BCCs, provide compelling support for the concept that these tumors represent an aberrant form of follicle organogenesis, and uncover potential limitations to treating BCCs using Hh pathway inhibitors.

Animals↗

PubMed2003

Hedgehog signaling regulates sebaceous gland development.

Epithelial progenitor cells in skin give rise to multiple lineages, comprising the hair follicle, an associated sebaceous gland, and overlying epidermis; however, the signals that regulate sebocyte development are poorly understood. We tested the potential involvement of the Hedgehog pathway in sebaceous gland development using transgenes designed to either block or stimulate Hedgehog signaling in cutaneous keratinocytes in vivo. Whereas inhibition of the Hedgehog pathway selectively suppressed sebocyte development, Hedgehog pathway activation led to a striking increase both in size and number of sebaceous glands. Remarkably, ectopic Hedgehog signaling also triggered the formation of sebaceous glands from footpad epidermis, in regions normally devoid of hair follicles and associated structures. These ectopic sebaceous glands expressed molecular markers of sebocyte differentiation and were functional, secreting their contents directly onto the skin's surface instead of into a hair canal. The Hedgehog pathway thus plays a key role in sebocyte cell fate decisions and is a potential target for treatment of skin disorders linked to abnormal sebaceous gland function, such as acne.

Animals↗

PubMed2002

Complement C5b-9 membrane attack complex increases expression of endoplasmic reticulum stress proteins in glomerular epithelial cells.

In the passive Heymann nephritis (PHN) model of membranous nephropathy, complement C5b-9 induces glomerular epithelial cell (GEC) injury, proteinuria, and activation of cytosolic phospholipase A(2) (cPLA(2)). This study addresses the role of endoplasmic reticulum (ER) stress proteins (bip, grp94) in GEC injury. GEC that overexpress cPLA(2) (produced by transfection) and "neo" GEC (which expresses cPLA(2) at a lower level) were incubated with complement (40 min), and leakage of constitutively expressed bip and grp94 from ER into cytosol was measured to monitor ER injury. Greater leakage of bip and grp94 occurred in complement-treated GEC that overexpress cPLA(2), as compared with neo, implying that cPLA(2) activation perturbed ER membrane integrity. After chronic incubation (4-24 h), C5b-9 increased bip and grp94 mRNAs and proteins, and the increases were dependent on cPLA(2). Expression of bip-antisense mRNA reduced stimulated bip protein expression and enhanced complement-dependent GEC injury. Glomerular bip and grp94 proteins were up-regulated in proteinuric rats with PHN, as compared with normal control. Pretreatment of rats with tunicamycin or adriamycin, which increase ER stress protein expression, reduced proteinuria in PHN. Thus, C5b-9 injures the ER and enhances ER stress protein expression, in part, via activation of cPLA(2). ER stress protein induction is a novel mechanism of protection from complement attack.

Animals↗

PubMed2002

Identification of HDAC10, a novel class II human histone deacetylase containing a leucine-rich domain.

Histone acetylation is important for regulating chromatin structure and gene expression. Three classes of mammalian histone deacetylases have been identified. Among class II, there are five known members, namely HDAC4, HDAC5, HDAC6, HDAC7 and HDAC9. Here we describe the identification and characterization of a novel class II member termed HDAC10. It is a 669 residue polypeptide with a bipartite modular structure consisting of an N-terminal Hda1p-related putative deacetylase domain and a C-terminal leucine-rich domain. HDAC10 is widely expressed in adult human tissues and cultured mammalian cells. It is enriched in the cytoplasm and this enrichment is not sensitive to leptomycin B, a specific inhibitor known to block the nuclear export of other class II members. The leucine-rich domain of HDAC10 is responsible for its cytoplasmic enrichment. Recombinant HDAC10 protein possesses histone deacetylase activity, which is sensitive to trichostatin A, a specific inhibitor for known class I and class II histone deacetylases. When tethered to a promoter, HDAC10 is able to repress transcription. Furthermore, HDAC10 interacts with HDAC3 but not with HDAC4 or HDAC6. These results indicate that HDAC10 is a novel class II histone deacetylase possessing a unique leucine-rich domain.

Amino Acid Sequence↗