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Biomedical subjects

Z Yang

Publications and source records attributed to Z Yang.

At least 433 records · Page 24Linked to original sources
PubMed1999

[Expression of estradiol receptors in mast cells of the upper airway].

OBJECTIVE: To examine the expression of estrogen receptors in mast cells, CD4+, CD8+ and CD68+ cells in human nasal polyps. METHODS: Immunohistochemical and dual immunostaining methods were used with mouse monoclonal antibodies against human estrogen receptors, a range of human immune cell types included CD4+ (helper T-cells), CD8+ (suppressor/cytotoxic T-cells), CD68+ (Macrophages) cells and mast cells. RESULTS: Coincident with the known features of human nasal polyps, all the immune/inflammatory cell types examined were clearly detected with corresponding monoclonal antibodies. The cells positive for estrogen receptor were morphologically similar to the mast cells but distinct from CD4+, CD8+ or CD68+ cells. The cells stained for estrogen receptors by dual immunostaining coincided exactly with cells labeled as mast cells but differed from CD4+, CD8+ or CD68+ cells. CONCLUSION: Estrogen receptors express only in mast cells, but not in CD4+, CD8+ or CD68+ cells in the human upper airway.

Adult↗
PubMed1999

[Clinical analysis of traumatic optic nerve dysfunction].

OBJECTIVE: To evaluate the key factors in diagnosis, treatment and prognosis of optic nerve trauma at the canalicular segment. METHODS: Twenty-six patients with optic nerve dysfunction resulted from trauma to the nerve at canalicular segment were analyzed. All the patients received orbital CT scans, corticosteroid therapy and surgical optic canal decompression through the external ethmoid approach. RESULTS: With the help of CT scan, the total diagnostic rate was 66.7%; that for canal fracture was 81.3%, for nerve swelling 56.3%. The improvement rate of surgical decompression depended on the time of visual loss and types of toauma. Specifically, the improvement rate was 57.1% in patients with visual loss occurred immediately after the trauma, 83.3% in patients with visual loss occurred a moment after the trauma, 66.7% in patients with optic nerve swelling and 56.3% with optic canal fracture. The possibility of recovery decreased with delay of the surgery. CONCLUSION: Orbital CT scan facilitates the diagnosis of optic canal fracture. However, the possibility of traumatic optic nerve dysfunction can not be ruled out in patients without the sign of canal fracture in the CT scan. The key factors in determining nerve recovery were associated with the severity of optic nerve trauma and the chance of surgery. Serious trauma and delay of the surgery may result in the blindness.

Adolescent↗
PubMed1999

Overexpression of c-fos and Rb proteins in radiation-induced skin ulcers.

We established an animal model of radiation-induced skin ulcers in rats irradiated with 35 to 55 Gy y-rays. The pathological changes were observed for 1 year. Immunohistochemical studies were performed on 72 radiation-induced skin ulcer specimens using c-fos and Rb protein polyclonal antibodies. We found that the overexpression rate of c-fos was 45.8% and of Rb was 63.9%. The overexpression of c-fos was mainly seen in the nuclei of activated squamous epithelial cells and in some fibroblasts and endothelial cells of arterioles in the deep part of the skin ulcers. The overexpression of Rb had the same localization. Our results suggest that the changes in c-fos and Rb proteins may be related to the poor healing of radiation-induced skin ulcers.

Animals↗
PubMed1999

Overexpression of c-erbB-2 and EGF-R proteins in radiation-induced skin ulcers.

We established an animal model of radiation-induced skin ulcers in rats irradiated with 35-55Gy gamma-rays. The pathological changes were studied for 1 year. Immunohistochemical studies were performed on 72 radiation-induced skin ulcer specimens using c-erbB-2 and epidermal growth factor receptor (EGF-R) protein antibodies. We found that the overexpression rate of c-erbB2 oncoprotein was 59.7% and of EGF-R was 70.8%. The overexpression of c-erbB-2 was chiefly seen in the activated squamous epithelial cells and in the cytoplasm of fibroblasts, endothelial cells, and leiomyocytes of the arteriolar media in the deep part of the ulcers. The overexpression of EGF-R had the same localizations. It is suggested that the overexpression of c-erbB-2 and EGF-R proteins may be due to the poor healing of the radiation-induced skin ulcers.

Animals↗
PubMed1999

Overexpression of p53 and MDM2 proteins in rat radiation-induced skin ulcers.

We established an animal model of radiation-induced skin ulcer in rats that were locally irradiated with 35 to 55 Gy gamma-rays. The pathological changes were observed for 1 year. Immunohistochemical studies using p53 and MDM2 protein polyclonal antibodies were performed on 72 radiation-induced skin ulcer specimens. The results showed that the overexpression rate of p53 protein was 9.7% and of MDM2 was 19.4%. The overexpression of p53 was chiefly seen in the nuclei of the activated squamous epithelial cells and in the fibroblasts and endothelial cells of arterioles in the deeper part of the skin ulcers. The overexpression of MDM2 had the same localizations. These results suggest that the changes of p53 and MDM2 may be related to the poor healing rate of radiation-induced skin ulcers.

Animals↗
PubMed1999

[Study on the Co(DC)2-NaDC mixed micelle system].

Eight coordinated complex samples of CoCl2-NaDC were obtained,using various concentration and initial molar ratio of CoCl2 and NaDC. They exhibited distinct appearances and characters. Their different structures and components were investigated by FTIR spectroscopy, X-ray diffraction analysis and ICP analysis. We can give the following conclusions: (1) when the concentration of NaDC is smaller than C.M.C, Co2+ ions react with mono-molecular NaDC and the component of the pink wadding-like resultant is Co(DC)2 x 3H2O. (2) When the concentration of NaDC is larger than C.M.C, and the concentration of CoCl2 is higher (0.5 mol/L), Co2+ ions destroy NaDC micelles, and the component of the pink wadding-like resultant is also Co(DC)2 x 3H2O. (3) When the concentration of NaDC is larger than C.M.C, and the concentration of CoCl2 is lower (0.1 mol/L or more lower), Co(DC)2 and NaDC may form mixed micelles, and some of NaDC micelles connect with each other through the Co2+ bridges to produce complicate Co(DC)2-NaDC complex with gel character and macromolecular network structure. In human body,the concentration of metal ions is usually lower and the concentration of NaDC is larger than C.M.C, So the third kind is suggested as an ideal model of the interaction between Co2+ ions and NaDC in vivo.

Bile Acids and Salts↗
PubMed1999

[Direct upconversion sensitization luminescence of Tm(0.1) Yb (10.9) oxyfluoride vitroceramincs].

This paper studied the direct upconversion sensitization luminescence of Tm (0.1) Yb (10.9) oxyfluoride vitroceramics pumped by 966 nm diode laser for the first time. We found that there are both strong 477 nm three-photon upconversion fluorescence of 1G4 --> 3H6 transition and 799.5 nm two-photon upconversion fluorescence of 3H4 --> 3H6 transition as well as weak upconversion fluorescence of 1D2 --> 3H6, 1Dz --> 3F4,1G4 --> 3F4 and 3F3 --> 3H6 transitions at 361 nm, 449.5 nm, 647.0 nm and (679.5, 698.5 nm), respectively.

English Abstract↗
PubMed1999

Telomerase activity in radiation-induced chronic human skin ulcers.

An increasing activity of telomerase is considered to be a reliable molecular biological marker for malignancy. There is much research work on telomerase detection in malignant tumors, but no such investigation was carried out in chronic skin ulcers induced by radiation. We investigated the levels of telomerase activity in radiation-induced chronic human skin ulcers and the possible relationship between the enzyme and cancer transformation. We used the nonisotopic telomere repeat amplification protocol (TRAP) in 20 cases of chronic human skin ulcers induced by radiation, 5 cases of normal skin, 2 of burned skin, and 5 of carcinoma. Our results showed that the positive rate for telomerase activity was 30% in chronic radiation skin ulcers, 0% in normal and burned skin, and 100% in carcinoma. The telomerase activity in radiation ulcers was weaker than that detected in carcinoma. We suggest that the telomerase activity assay could be used as a marker for predicting the prognosis and the effect of treatment in chronic human skin ulcers induced by radiation.

Cell Transformation, Neoplastic↗
PubMed1998

Telomerase is controlled by protein kinase Calpha in human breast cancer cells.

Telomerase, a specialized RNA-directed DNA polymerase that extends telomeres of eukaryotic chromosomes, is repressed in human somatic tissues and becomes activated during tumor progression in most human cancers. To date, little is known about how telomerase is activated and controlled in cancer, although activation is thought to be involved in cancer cell immortalization. Here, we report that human telomerase-associated protein 1 (hTEP1) and the telomerase catalytic subunit (human telomerase reverse transcriptase (hTERT)) are phosphoproteins and that their phosphorylation is a prerequisite for the activation of telomerase in intact human breast cancer cells. Identified by hTEP1 peptide affinity chromatography, protein kinase Calpha mediates the phosphorylation of hTEP1 and hTERT and induces a marked increase in telomerase activity. Thus, phosphorylation of hTEP1 and hTERT by protein kinase Calpha represents an essential step in the generation of a functional telomerase complex in the initiation and maintenance of telomerase activity in human cancer.

Amino Acid Sequence↗
PubMed1998

Synthesis of 5-substituted quinazolinone derivatives and their inhibitory activity in vitro.

Quinazolinone derivatives I and their methyl esters were synthesized and evaluated as nonclassical lipophilic inhibitors of thymidylate synthase. Compounds Ib and Ic containing OH and CO2H as R substituents, respectively, were most effective, indicating that hydrogen bonding may contribute to the increased inhibitory activity. These compounds further showed high cytotoxic activity against tumor cells in culture.

Animals↗
PubMed1998

Influence of the hypothalamic paraventricular nucleus on cardiovascular neurones in the rostral ventrolateral medulla of the rat.

1. The question of whether neurones in the paraventricular nucleus (PVN) of the hypothalamus have an excitatory influence on reticulo-spinal vasomotor neurones of the rostral ventrolateral medulla (RVL) has been addressed in this study using anaesthetized rats. 2. Extracellular microelectrode recordings were made from sixty vasomotor neurones in the RVL, identified by their cardiac cycle-related probability of discharge, by the decrease in activity in response to an increase in arterial blood pressure produced by intravenous phenylephrine and by the increase in activity in response to a decrease in blood pressure produced by intravenous nitroprusside. 3. More than 70 % of these RVL vasomotor neurones were identified as spinally projecting by antidromically activating their axons via a stimulating electrode in the lateral funiculus of the T2 or T10 segment of spinal cord. 4. Activation of neurones at different sites in the PVN with a microinjection of d,l-homocysteic acid (DLH) elicited either pressor or depressor responses. 5. At PVN pressor sites fifteen RVL vasomotor neurones were shown to be activated prior to the blood pressure change. A further twenty RVL vasomotor neurones were observed to decrease activity following the blood pressure rise. At PVN depressor sites twelve RVL neurones were inhibited prior to the blood pressure change whereas another thirteen identified RVL neurones increased their discharge following the fall in blood pressure. 6. In three rats single shock electrical stimulation at a PVN pressor site, first identified with DLH, elicited a single or double action potential in thirteen RVL neurones with a latency of 27 +/- 1 ms. 7. It is concluded that PVN neurones may elicit increases in blood pressure via excitatory connections with RVL-spinal vasomotor neurones, and that other PVN neurones may elicit decreases in blood pressure via inhibitory connections with these RVL neurones.

Animals↗
PubMed1998

Functional analyses of troponin T mutations that cause hypertrophic cardiomyopathy: insights into disease pathogenesis and troponin function.

Mutations in a number of cardiac sarcomeric protein genes cause hypertrophic cardiomyopathy (HCM). Previous findings indicate that HCM-causing mutations associated with a truncated cardiac troponin T (TnT) and missense mutations in the beta-myosin heavy chain share abnormalities in common, acting as dominant negative alleles that impair contractile performance. In contrast, Lin et al. [Lin, D., Bobkova, A., Homsher, E. & Tobacman, L. S. (1996) J. Clin. Invest. 97, 2842-2848] characterized a TnT point mutation (Ile79Asn) and concluded that it might lead to hypercontractility and, thus, potentially a different mechanism for HCM pathogenesis. In this study, three HCM-causing cardiac TnT mutations (Ile79Asn, Arg92Gln, and DeltaGlu160) were studied in a myotube expression system. Functional studies of wild-type and mutant transfected myotubes revealed that all three mutants decreased the calcium sensitivity of force production and that the two missense mutations (Ile79Asn and Arg92Gln) increased the unloaded shortening velocity nearly 2-fold. The data demonstrate that TnT can alter the rate of myosin cross-bridge detachment, and thus the troponin complex plays a greater role in modulating muscle contractile performance than was recognized previously. Furthermore, these data suggest that these TnT mutations may cause disease via an increased energetic load on the heart. This would represent a second paradigm for HCM pathogenesis.

Animals↗
PubMed1998

Four ubiquitously expressed genes, RD (D6S45)-SKI2W (SKIV2L)-DOM3Z-RP1 (D6S60E), are present between complement component genes factor B and C4 in the class III region of the HLA.

The association of the HLA class III region with many diseases motivates the investigation of unidentified genes in the 30-kb segment between complement component genes Bf and C4. RD, which codes for a putative RNA binding protein, is 205 bp downstream of Bf. SKI2W (HGMW-approved symbol SKIV2L), a DEVH-box gene probably involved in RNA turnover, is 171 bp downstream of RD (HGMW-approved symbol D6S45). RP1 (HGMW-approved symbol D6S60E) is located 611 bp upstream of C4. The DNA sequence between human RD and RP1 was determined and the exon-intron structure of SKI2W elucidated. SKI2W consists of 28 exons. The putative RNA helicase domain of Ski2w is encoded by 9 exons. Further analysis of the 2.5-kb intergenic sequence between SKI2W and RP1 led to the discovery of DOM3Z. The full-length cDNA sequence of DOM3Z encodes 396 amino acids with a leucine zipper motif. Dom3z-related proteins are present in simple and complex eukaryotes. In Caenorhabditis elegans, Dom3z-related protein could be involved in the development of germ cells. Human RD-SKI2W and DOM3Z-RP1 are arranged as two head-to-head oriented gene pairs with unmethylated CpG sequences at the common 5' regulatory region of each gene pair. The ubiquitous expression pattern suggests that these four genes are probably housekeeping genes.

Amino Acid Sequence↗
PubMed1998

Chromosomal localization reveals three kinesin heavy chain genes in mouse.

Kinesin-related proteins constitute a superfamily of microtubule-dependent motors that play important roles in organelle transport and cell division. These molecules share a conserved motor region of approximately 340 amino acids, which is attached to diverse "tail" or cargo-binding domains. The kinesin superfamily was first defined by kinesin heavy chain, which is the principal component of "true" kinesin. Invertebrates appear to possess only a single gene encoding kinesin heavy chain. Mammals appear to have two or more genes encoding kinesin heavy chain, although the precise situation has been unclear. Here we definitively demonstrate that mouse has three kinesin heavy chain genes, Kif5a, Kif5b, and Kif5c. Kif5a, Kif5b, and Kif5c map to mouse chromosomes 10, 18, and 2; Kif5a and Kif5c appear to be expressed only in neuronal tissues by Northern blot analysis while Kif5b appears to be ubiquitous in its expression.

Animals↗
PubMed1998

The human DEVH-box protein Ski2w from the HLA is localized in nucleoli and ribosomes.

The human helicase gene SKI2W is located between RD and RP1 in the class III region of the major histocompatibility complex. Transcripts of SKI2W are detectable in RNA samples isolated from multiple tissues. The protein product Ski2w shares striking amino acid sequence similarities to the yeast antiviral protein Ski2p that controls the translation of mRNAs, probably based on the mRNA structural integrity. Whether this translational regulation mechanism for cellular and viral RNAs exists in mammals is under investigation. Antisera against human Ski2w were generated using fusion proteins produced in bacteria or insect cells. Western blot analysis showed that the endogenous Ski2w protein is approximately 140 kDa in size and is enriched in polysomal fractions of cytoplasmic extracts from HeLa cells. Ribosomal profile studies revealed that Ski2w distributed throughout the entire sucrose gradient in the presence of Mg2+, but co-sedimented with the 18S rRNA-containing 40S subunit and the small ribosomal subunit protein S27a in the presence of EDTA. The co-sedimentation of Ski2w with the 40S subunit is not affected by RNase A treatment of the cell extract, or the addition of KCl to 0.5 M, suggesting that Ski2w is associated with the 40S ribosomal subunit. Indirect immunofluorescence experiments showed that human Ski2w is localized in the nucleoli and in the cytoplasm. In essence, human Ski2w is present at the sites of ribosome biogenesis and protein synthesis.

Amino Acid Sequence↗