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Biomedical subjects

H Xu

Publications and source records attributed to H Xu.

At least 577 records · Page 32Linked to original sources
PubMed1996

[Observations on signet cell invasion and metastasis in extra-mammary Paget's disease].

In order to evaluate the level of cell differentiation in extramammary Paget's disease (EMPD) and the relation with prognosis, the pathologic morphology of 20 EMPD cases were reviewed. We found two marked features of the invasive and metastatic Paget's cells: first, the Pagat cells were usually of signet ring shape; second, the cells formed gland-like structures. These features can be regarded as low differentiation and important risk factors for invasion and metastasis in EMPD.

Adult↗
PubMed1996

[Anti-herpes virus action of ethanol-extract from the root and rhizome of Rheum officinale Baill].

The study has shown that the cytotoxity of ethanol-extract from the root and rhizome of Rheum of ficinale is very low. It shows no cytotoxity even at 20,000 micrograms/ml and on the contrary tends to promote cell growth. Obvious anti-viral action can be observed in cell culture. The minimum inhibition dose for herpes simplex virus (HSV) is 100 micrograms/ml. Also, the extract helps to prevent cells from viral infections and has some direct effect on viral particles.

Animals↗
PubMed1996

[Percutaneous cervical discectomy: a report of twenty-five cases].

Twenty-five patients with herniations of the cervical intervertebral disks were treated with percutaneous cervical discectomy. The surgical instruments and technique were improved based on those for percutaneous lumbar discectomy. All the patients well recovered with an average follow-up period of 15.6 months (from 4 to 23 months) and no major complications was encountered. The method is safe, easy and effective. The anatomy, principles and maneuvers related to the operation are discussed in detail.

Adult↗
PubMed1996

[Effects of amiloride and glycogen depletion on post-ischemic reperfusion injury of isovolumic perfused rat hearts].

The effects of amiloride (0.5 nmol/L) and glycogen depletion were studied to find out the possible roles of Na(+)-H+ exchange of ischemia reperfusion injury in the isovolumic perfused isolated rat hearts. The data indicated that, compared to control group, both amiloride and glycogen depletion accelerated recovery of hemodynamics and reduced leakage of LDH and the formation of myocardial MDA which was accompared by a higher activity of mitochondrial GSH-Px and lesser accumulation of intracellular Na+, Ca2+. That Na(+)-H+ and Na(+)-Ca2+ exchanges might play a critical role in post-ischemic reperfusion injury is discussed.

Amiloride↗
PubMed1996

[Effect of magnesium on postischemic reperfused myocardial mitochondria].

Isovolumic rat heart preparations were exposed to low flow ischemia (0.2 ml/min) for 60 min, followed by 30 min of reperfusion. The concentration of Mg2+ was maintained 1.2 mmol/L throughout the study in group 2, while increased to 15 mmol/L or depleted to zero during ischemia only in group 3 and group 1 respectively. High concentration Mg2+ showed a significantly protective effect on Ca-ATPase activity and synthesis ability of ATP in myocardial mitochondria, and decreased its calcium overload. Thus it appears that high concentration Mg2+ infusion may partially reverse postischemic reperfusion injury to heart.

Animals↗
PubMed1996

[Preliminary research on Bifidobacterium cuniculi in stomach and intestines of rabbits].

The distribution of Bifidobacterium in stomach and intestines of ten healthy rabbits were studied by microecological methods. The results showed that Bifidobacterium exist in stomach, small intestine and large intestine, the amount hightest in large intestine, second in jejunum and no finnd in duodenum. Being isolated, purified and biologically identified, the bacteria was identified as Bifidobacterium cuniculi, whose other biological characteristics also was studied.

Animals↗
PubMed1996

[A report of 164 cases of Bell's palsy].

In order to research the relationship between various methods of treatment and their prognosis on Bell's palsy, 164 cases of Bell's Palsy were reviewed. According to the results of ENoG test, 164 cases were divided into three groups A, B1 and B2. Group A: the paretic side ENoG loss was less than 90%, group B1: the ENoG loss was more than 90% and without surgical decompression of facial nerve, group B2: the ENoG loss was more than 90% and with surgical decompression. All of the patients had follow up for 1-3 years or even longer after onset. The grades of recovery of facial function were evaluated by modified classification system as originally proposed by Portmann. The facial function of 77 cases of group A were recovered satisfactorily except 3 patients, the average points were 19.22 +/- 1.18. The average points of group B1 (41 cases) and B2 46 cases were 14.4 +/- 3.49 and 15.4 +/- 2.08 respectively. Comparing the results with group B1, B2 and A, there was no statistical significant difference (P > 0.05) between group B1 and B2, but the results of group A were statistically significant better than group B1 and B2 (P < 0.01). The prognosis of Bell's palsy might mainly depend on the degree of degeneration of facial nerve. A satisfactory recovery can be expected when ENoG test loss was less than 90%. If ENoG loss was more than 90%, neither surgical decompression nor steroids therapy could change the prognosis statistically.

Adolescent↗
PubMed1996

[Pharmacognostical study on the Chinese drug biejia].

The Chinese drug Biejia is taken from a variety of animals. In this paper, 3 kinds of Biejia from different genera have been studied in their pharmacognostical characteristics and microproperties. A key has been complied based on the experimental results.

Animals↗
PubMed1996

Effects of anti-erbB-2 (HER-2/neu) recombinant oncotoxin AR209 on human non-small cell lung carcinoma grown orthotopically in athymic nude mice.

The recombinant oncotoxin AR209 [e23(Fv)PE38KDEL; formerly OLX-209] was developed to treat neoplasia that expresses the c-erbB-2 (HER-2/neu) protein product p185(erbB-2). The AR209 compound contains a single-chain antibody domain specific for p185(erbB-2), coupled with a portion of the Pseudomonas exotoxin. The drug has been shown to be effective in inhibiting cells that overexpress erbB-2 due to gene amplification and in cells that do not contain amplified erbB-2 but express slightly higher levels of the protein than normal cells do. To test the efficacy of AR209 on human lung tumors, athymic nude mice were inoculated intrathoracically with a cell line derived from a poorly differentiated lung adenocarcinoma. This cell line, termed 201T, expresses moderately elevated levels of p185(erbB-2) 7.6-fold over normal bronchial epithelium. Mice treated with i.v. injections of AR209 for 5 weeks after orthotopic tumor implantation had smaller tumors and in 20% of cases showed no evidence of disease. The data from this study indicate that AR209 may be an effective treatment for patients with non-small cell lung cancers that express p185(erbB-2).

Animals↗
PubMed1995

(E)-8-benzylidene derivatives of 2-methyl-5-(3-hydroxyphenyl)morphans: highly selective ligands for the sigma 2 receptor subtype.

The determination of the structure and function of the sigma receptor subtypes and their physiological role(s) has been impeded by the unavailability of selective ligands. We have developed a new class of sigma subtype selective receptor ligands that are (E)-8-benzylidene derivatives of the synthetic opioid (+/-)-, (+)-, and (-)-2-methyl-5-(3-hydroxyphenyl)morphan-7-one (1). The derivatives can be prepared by reaction of 1, (+)-1, and (-)-1 with the appropriate benzaldehyde under Claisen-Schmidt conditions. Incorporation of substituted (E)-8-benzylidene moieties onto the 7-keto precursor of (+)-2-methyl-5-(3-hydroxyphenyl)morphan, (+)-1, produces compounds (-)-2 through (-)-7 (5.8-32.0 nM, sigma 1), which have between a 25- and 131-fold increase in affinity for the sigma 1 receptor subtype relative to the keto precursor (+)-1 (Ki = 762 nM, sigma 1). Compound (-)-2 is the most selective of this group (16-fold) for the sigma 1 subtype versus sigma 2. Substitution of an (E)-8-benzylidene moiety onto the 7-keto precursor of (-)-2-methyl-5-(3-hydroxyphenyl)morphan, (-)-1, produces compounds (+)-2-(+)-9 (6.4-52.6 nM, sigma 2), which have at least a 475-3906-fold increase in affinity for the sigma 2 receptor subtype relative to the keto precursor (-)-1 (Ki = 25 x 10(3) nM). This enhancement of sigma 2 receptor affinity is accompanied by substantial selectivity of all of these dextrorotatory products for the sigma 2 relative to the sigma 1 subtype (32-238-fold), and thus, they are among the most sigma 2 selective compounds currently known. Furthermore, the sigma 1 subtype is highly enantioselective for the levorotatory isomers, (-)-2-(-)-7 (41-1034-fold), whereas the sigma 2 subtype is only somewhat enantioselective for the dextrorotatory isomers, (+)-2-(+)-7 (2.6-9.3-fold). All of these derivatives retain substantial affinity for the mu opioid receptor. Despite the high affinity of the dextrorotatory derivatives for the mu opioid receptor, the high affinity and selectivity for sigma 2 over sigma 1 sites will surely prove beneficial as tools for the delineation of the function and physiological role of sigma 2 receptors.

Animals↗
PubMed1995

Cloning, expression and immunological characterization of Ory s 1, the major allergen of rice pollen.

We have isolated and characterized a cDNA clone, Ory s 1, encoding a group-1 allergen of rice pollen. The Ory s 1 protein shows significant sequence identity to the major allergen of rye-grass pollen, Lol p 1. RNA gel blot analysis shows that the Ory s 1 gene is expressed in mature anthers, but not in vegetative or other floral tissues tested. Southern blot analysis indicates that this clone represents a member of a small gene family in rice. Western blot analyses of total rice pollen proteins with the group-1 allergen-specific monoclonal 3A2 and IgE antibodies from grass pollen-allergic patients, revealed the presence of cross-reactive antigenic and allergenic epitopes in Ory s 1.

Allergens↗
PubMed1995

Opioid peptide receptor studies. 4. Antisense oligodeoxynucleotide to the delta opioid receptor delineates opioid receptor subtypes.

Prior work in our laboratory has identified putative subtypes of delta (delta cx-1, delta cx-2, delta ncx-1, delta ncx-2) and kappa 2 (kappa 2a and kappa 2b) receptors. Previous studies showed that chronic (three day) i.c.v. administration of antisense oligodeoxynucleotide to the cloned delta opioid receptor selectively decreased [3H][D-Ala2,D-Leu5]enkephalin binding to the delta ncx site, not the delta cx-2 site. The present study extends this work by demonstrating that delta antisense DNA selectively affects the delta ncx-2 site sparing the other putative delta receptor subtypes and kappa 2 receptor subtypes. This selectivity is not due to anatomically specific effects of delta antisense DNA since autoradiograms show that delta binding is reduced in all regions of the brain after chronic i.c.v. administration of delta antisense DNA. These data strongly suggest that the delta cx-1, delta cx-2, delta ncx-1, kappa 2a and kappa 2b binding sites are different proteins than the delta ncx-2 binding site, which, based on its sensitivity to delta antisense DNA, is synonymous to the cloned delta opioid receptor. Viewed collectively, these data suggest that administration of delta antisense DNA, and by extension other receptor-selective antisense DNA, is a powerful approach to distinguishing between postulated receptor subtypes.

Animals↗
PubMed1995

Regulated formation of Golgi secretory vesicles containing Alzheimer beta-amyloid precursor protein.

Phorbol esters, activators of protein kinase C (PKC), regulate the relative utilization of alternative processing pathways for the Alzheimer beta-amyloid precursor protein (beta-APP) in intact cells, increasing the production of nonamyloidogenic soluble beta-APP (s beta-APP) and decreasing that of neurotoxic beta-amyloid (A beta) peptide. The molecular and cellular bases of PKC-regulated beta-APP cleavage are poorly understood. Here we demonstrate in a reconstituted cell-free system that activation of endogenous PKC increases formation from the trans-Golgi network of secretory vesicles containing beta-APP and that this effect can be mimicked by purified PKC. The results demonstrate directly that PKC is involved in regulation of secretory vesicle formation and provide a mechanism by which PKC may reduce the formation of the A beta peptide characteristic of Alzheimer disease.

Aluminum Compounds↗
PubMed1995

The kinase-dependent function of Lck in T-cell activation requires an intact site for tyrosine autophosphorylation.

The cytoplasmic protein tyrosine kinase p56lck (Lck) has important signaling roles in T-cell development and activation. We have mutated the two known regulatory tyrosine residues of CD4-associated Lck and examined the effects on its kinase-dependent function in an antigen-specific CD4-dependent T-cell hybridoma. Substitution of phenylalanine for the negative regulatory tyrosine-505 within a CD4/Lck chimera resulted in a slightly increased response to antigen, whereas mutation of the major in vitro autophosphorylation site (tyrosine-394) completely abolished the kinase-dependent function of Lck. Even though its kinase activity was only slightly affected, the F394 mutant behaved similarly to a catalytically inactive chimeric protein. Cross-linking of the F505 mutant, but not of wild-type Lck or F394 mutants, resulted in tyrosine phosphorylation of multiple cellular proteins. Although the pattern of tyrosine phosphorylation resembled that observed upon T-cell receptor cross-linking, there was no induction of interleukin-2 synthesis upon cross-linking of the chimeric protein. These results suggest that the activity of the Lck kinase domain in vivo is controlled by dephosphorylation at the negative regulatory site and phosphorylation at the positive regulatory (autophosphorylation) site. Additionally, our data show that the specific kinase activity of Lck towards an artificial substrate need not correlate with its ability to phosphorylate cellular proteins or its biological function.

Animals↗
PubMed1995

Cathepsin D-like aspartyl protease activity mediates the degradation of tissue-type plasminogen activator/plasminogen activator inhibitor-1 complexes in human monocytes.

Plasminogen activator inhibitor-1 (PAI-1) is the most important inhibitor of tissue-type plasminogen activator (t-PA) in plasma and plays a major role in the regulation of fibrinolysis. Plasma t-PA/PAI-1 complexes are cleared via a receptor-dependent mechanism in hepatocytes, while the fate of complexes formed in the extracellular matrix and in thrombi is less well understood. In this study, the degradation of t-PA/PAI-1 complexes by monocytes was examined. THP-1 monocytoid cells and freshly isolated human monocytes internalize and degrade [125I]t-PA/PAI-1 complexes at rates of 11.4 +/- 5.9 (mean +/- S.D.) and 44.6 +/- 6.3 ng/10(6) cells/h, respectively. Degradation is blocked by receptor-associated protein (RAP), indicating a member of the low density lipoprotein (LDL) receptor family is involved in the uptake/degradation of t-PA/PAI-1 complexes by monocytes. Degradation of t-PA/PAI-1 complexes is also inhibited by chloroquine and by pepstatin A, suggesting that a lysosomal aspartyl protease is likely involved. SDS-PAGE and Western blotting demonstrated that the purified lysosomal aspartyl protease, cathepsin D, is capable of digesting t-PA (t1/2 15 min), active PAI-1 (t1/2 2 h), and t-PA/PAI-1 complex (t1/2 30 min). Cathepsin D sequentially cleaves PAI-1 after hydrophobic amino acids, yielding lower molecular weight fragments. PAI-1 conformation influences the degradative efficiency of cathepsin D, with vitronectin-bound PAI-1 and latent PAI-1 exhibiting resistance to proteolysis and > 10-fold prolongation in t1/2. These data provide evidence that t-PA/PAI-1 complexes are internalized by human monocytes via a member of the low density lipoprotein (LDL) receptor family, and identifies cathepsin D-like aspartyl protease activity as largely responsible for the degradation of these complexes. Furthermore, vitronectin-bound PAI-1 and latent PAI-1 are relatively resistant to degradation by cathepsin D, which may be of importance in complex physiological environments.

Cathepsin D↗