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Biomedical subjects

W Jia

Publications and source records attributed to W Jia.

69 records · Page 4Linked to original sources
PubMed1994

Involvement of muscarinic acetylcholine receptors in regulation of kitten visual cortex plasticity.

Receptor autoradiographic methods specific for M3 and M1 muscarinic acetylcholine receptors were used to investigate the development and input-dependent laminar redistribution of these receptor populations during the critical period for kitten visual cortex plasticity. Analysis of the binding curves of [3H]4-diphenylacetyl-N-methyl-piperidine (4-DAMP) and [3H]pirenzepine (PZ) indicated that these two ligands bound heterogeneously to muscarinic acetylcholine receptors with different affinities. While [3H]4-DAMP showed a high affinity for M3 receptors and much lower affinities for M1 and M2 receptors, [3H]PZ displayed higher affinity for M1 receptors. By carefully choosing concentrations of labelled and unlabeled ligands, the patterns of laminar distribution for both receptor subtypes within visual cortex were obtained. Both receptors were most concentrated in cortical layer IV immediately after birth and during the most sensitive period of visual cortex plasticity. The binding density for both receptor subtypes thinned out progressively in this layer to concentrate in more superficial layers as plasticity waned with age. Moreover, interruption of visual or spontaneous input to visual cortex induced either by lesion or by tetrodotoxin infusion into lateral geniculate nucleus prevented the developmental redistribution of these receptors from layer IV to superficial layers, that is, the pattern of laminar distribution remained that of the age at which the lesion or tetrodotoxin infusion into the lateral geniculate nucleus was performed. The results indicate that the developmental expression of M3 and M1 muscarinic acetylcholine receptors in kitten visual cortex depends on cortical inputs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Development and regulation of beta adrenergic receptors in kitten visual cortex: an immunocytochemical and autoradiographic study.

The developmental pattern and laminar distribution of beta 1 and beta 2 adrenergic receptor subtypes were studied in cat visual cortex with autoradiography using [125I]iodocyanopindolol as a ligand and also with immunocytochemistry using a monoclonal antibody directed against beta adrenergic receptors. In the primary visual cortex of adult cats, the laminar distributions of both beta 1 and beta 2 adrenergic receptors revealed by autoradiography were very similar, with concentrations in layers I, II, III and VI. In young kittens (postnatal days 1 and 10), fewer beta adrenergic receptors were present, and they were concentrated in the deep cortical layers (V-VI) and subcortical white matter. Between postnatal days 15 and 40, beta adrenergic receptors increased in density more quickly in the superficial layers than they did in the deep and middle cortical layers. By postnatal day 40, the adult pattern was achieved, with two bands of intense binding in the superficial and deep cortical layers and a lower density in layer IV. Immunocytochemical techniques applied to adult cat cortex showed that beta adrenergic receptor-like immunoreactivity was found in different populations of neurons and glial cells. The immunoreactive neural cells were most dense in layers II, III and VI. About 50% of these immunoreactive neural cells were glial cells, primarily astrocytes. Immunoreactive pyramidal cells were mostly located in layers III and V. In layer IV, many stellate cells were stained. Immunoreactive astrocytes in the subplate and white matter progressively increased in number during development until adulthood. The pattern of laminar distribution and the developmental process was not affected by interrupting noradrenergic innervation from locus coeruleus either before or after the critical period. However, when visual input was interrupted by lesions of the lateral geniculate nucleus in young kittens (postnatal day 10), the density of both beta adrenergic receptor subtypes decreased significantly in the deep cortical layers. Lateral geniculate nucleus lesions in adult cats resulted in a pronounced decrease in beta adrenergic receptor density in layer IV.

Aging↗
PubMed1993

Comparison of the dynamics of an engineered insulin monomer and dimer by acid-quenched amide proton exchange. Non-local stabilization of interchain hydrogen bonds by dimerization.

Dynamic differences between an engineered insulin monomer and dimer are investigated under physiological conditions by an adaptation of the method of acid-quenched amide proton exchange. Although exchange lifetimes of amide protons involved in intrachain hydrogen bonds are similar in the two analogs, dimerization specifically stabilizes two interchain hydrogen bonds (LeuB6-NH...O = C-CysA6 and CysA11-NH...O = C-GluB4) that are distant from the dimer interface. Such non-local stabilization demonstrates that fluctuations in the tertiary structure of the monomer are damped by dimerization. As the B6-A6 and A11-B4 hydrogen bonds are specific to the crystallographic T-state, their stabilization also indicates that the R-state (an allosteric feature of hexamer assembly) is not significantly populated in an isolated dimer. Our results are discussed in reference to recent hypotheses that crystal structures of insulin depict inactive conformers and that detachment of interchain contacts accompany receptor binding.

Amides↗
PubMed1993

[Study on the induction of active immunity in human by injecting human anti-HBs antibodies].

One hundred and three health volunteers were injected with various doses of human anti-HBs (Ab1). The anti-idotypic antibodies (Ab2) and anti-antiidiotypic antibodies (Ab)3 in sera were tested at intervals of 30 days with ELISA. We found that the dynamic changes between Ab2 and Ab3 of immune sera were cyclical by way of their interaction and the Ag-specific Ab3 were the same as Ab1 in specificity. The results reconfirmed that exogenous human anti-HBs could induce active immunity by activation of idiotypic network and regulation in human body suggesting that injection of Ig into body could bring about not only passive immunity but also active immunity.

Adolescent↗
PubMed1992

[Analysis of chemical constituent of essential oil in Lonicera japonnica Thunb. cultivated on the northern plain of Henan Province].

The chemical constituents of the essential oil in the dry flower and fresh flower of Lonicera japonica were analyzed by the GC-MS-DS technique and the superimposition of authentic samples. 27 and 30 monoterpenoids and sesquiterpenoids were identified from the essential oil of the dry flower and fresh flower respectively. The major constituents have been found to be linalool, geraniol, aromadendrene and eugenol etc.

Acyclic Monoterpenes↗
PubMed1990

[Expression of Pre-S1 and Pre-S2 in serum of patients with chronic type B hepatitis].

To study the expression of Pre-S1 and Pre-S2 and gene-encoded proteins of the hepatitic B virus, we investigated serum from 11 patients with chronic type B hepatitis in various phases, Pre-S1 and Pre-S2 proteins were detected by the monoclonal antibody-based enzyme method, the markers of active viral replication were determined with the presence of HBV-DNA and HBeAg. It was found that Pre-S1 was present in the serum of 3 patients with viral replication as well as of 6 out of 8 cases with no evidence of viral replication, Pre-S2 in the serum of 2 out of 3 patients with active viral replication as well as 4 out of 8 cases with no evidence of viral replication. The similar results also appeared in patient's serum in various phases. The data suggest that there is no correlation between the presence of the Pre-S1 or Pre-S2 proteins and active viral replication during the course of chronic type B hepatitis.

DNA Replication↗
PubMed1988

[Establishment and characteristics of a human synovial sarcoma cell line].

A human synovial sarcoma cell line (HSS-84), from a painful mass excised locally near the left sternoclavicular joint, was established and has been continuously propagated in vitro for more than one year through 54 passages till the end of 1985. Doubling time was 65 hr. The index of mitosis was 28.8%. The chromosome number for most of the cells was hypertriploid. The cells, stored in liquid nitrogen, had a good revival. Cytologically, some cells, showing elongated, spindle, stellate or spidery shape with prominent processes, were arranged in loose or bundled pattern, similar to sarcoma cells; some cells showed ovoid and polygonal in mosaic arrangement, similar to epithelioid cells. Both features indicated biphasic differentiation of the cells. By electron microscopy, the cells consisted of light and dark cells with microvilli and obvious abnormality. Histopathologically, the tumor, from which HSS-84 originated, was a biphasic differentiation synovial sarcoma. It was composed of malignant spindle interstitial cells and malignant epithelioid cells lining the clefts or spaces. The latter was similar to cultured cells by electron microscopy. HSS-84 was identical with the donor. HSS-84 establishment will be useful for research on diagnosis, therapy, origin and biphasic differentiation of the synovial sarcoma.

Animals↗
PubMed1987

[Establishment of a human lung alveolar cancer cell strain and its characteristics].

A human lung alveolar cancer cell strain (HAC-84), isolated from lung adenocarcinoma cell line in Gejiu (GLC-82) by colony selecting method, has been continuously propagated in vitro for more than 2 years through 164 passages till May 1 st 1986. HAC has the typical malignant characteristics as GLC. There are plenty of phospholipid and osmiophilic multilamellar bodies in the cytoplasm of all cells and the membrane-like material in most of the nuclei, which differentiate HAC from GLC and the other types of lung cancers. The cytoplasmic inclusions are the same as those found in type II alveolar epithelial cells of the lung. So, HAC, originated from the type II alveolar cells, is identified as human lung alveolar cancer cell strain. It is significant in the research of the properties and origin of the alveolar cancer, the action and formation of the alveolar surfactants.

Adenocarcinoma↗
PubMedDate not supplied

Effect of prebonding procedures on shear bond strength of resin composite to pressable ceramic.

Low bond strength between tooth structure and restorative ceramic material is a major cause of ceramic fractures or failures. Prebonding measures performed on pressable ceramic material were evaluated and the different shear bond strengths obtained by each method were tabulated. The three individual groups were subjected to 9% hydrofluoric (HF) acid gel for 0, 1, and 5 minutes. The different acid-etched time groups were chemically treated with silane coupler alone, silane coupling agent with bonding agent, and bonding agent alone. The silane coupling agent produced the highest bond strength between the composite structure and the pressable ceramic restorative material. High bond values were achieved by etching the porcelain for one minute. The use of the silane coupling agent with a one minute 9% HF acid etch yielded the greatest bond strength.

Acid Etching, Dental↗