Biomedical subjects

C Zhao

Publications and source records attributed to C Zhao.

At least 199 records · Page 11Linked to original sources

PubMed1996

[Study on cellular proliferation activity of placental site trophoblastic tumor].

OBJECTIVE: To study the relationship among the cellular proliferation activity, benign clinical process and pathologic characteristics of placental site trophoblastic tumor (PSTT). METHODS: Paraffin-embedded blocks from ten patients with PSTT were reexamined by mitotic count, argyrophilic nucleolar organizer regions (AgNOR) staining and flow cytometric DNA analysis. Five cases of hydatidiform mole (HM) and 5 choriocarcinoma (CC) were chosen as controls. RESULTS: Mean mitotic figures of PSTT were 1.3 (0-3) per 10 high power field, while those of HM and CC were 0.8 (0-2) and 2.2 (1-4) respectively. AgNOR number of PSTT was 2.70 +/- 0.55 per cell, while those of HM and CC were 1.96 +/- 0.38 and 4.50 +/- 0.73 respectively. Flow cytometric DNA content revealed that PSTT had DNA index (DI) of 1.10, S phase of 16.7% and proliferating index (PI) of 26.6%. Eight of 10 Cases were followed up, 7 are alive and 1 died of primary lung cancer. CONCLUSION: PSTT has relative low cellular proliferation activity. The good clinical procedure and benign pathological feature of PSTT may be associated with its diploidy DNA and low cellular proliferation activity.

Adult↗

PubMed1996

[Treatment of cerebrospinal rhinorrhea under nasal endoscope with EC ear-head adhesive].

Five cases of cerebrospinal rhinorrhea in frontal, ethmoid or sphenoidal sinus were repaired under endoscope with ear-head adhesive with satisfactory results. The advantages of the method are as follows: (1) The sufferings of the patient are minor and intercranial complications are fewer: (2) The location and size of the fistula are clear under endoscope: (3) The success rate is higher due to the application of ear-head adhesive: (4) With the use of muscles and fasciae outside the nose, the bleeding in nasal cavity may be avoided: (5) The curettages of the mucosa around the fistula and dura mater is helpful to the adherence of ear-head adhesive with these tissues.

Adhesiveness↗

PubMed1996

[Microsurgical anatomical study of the wall of the cavernous sinus].

OBJECTIVE: To observe the microanatomical structures of the wall of cavernous sinus (CS) in order to provide anatomical basis for direct microsurgical operation to the CS. METHODS: 48 aides of the CS of adult cadavers were dissected in detail under operative microscope. RESULTS: The CS was a narrow and long irregular hexahedron in shape. The supperior wall, the posterior wall and the superficial dural layer of the lateral wall of the CS were formed by internal layer of the cerebral dura. The deep layer of the interal wall was formed by the sheaths of nerves II, IV, V1, V2 with a reticular membrane between these sheaths. There was a superficial compartment between the superficial layer and deep layer of the lateral wall in 31.25% of the specimens. The inferior wall of the CS was intracranial periosteum. The medial wall was formed by stretched fibres from the tentorium of hypophysis. The anterior aspect was formed by the sphenoid sinus and the superior orbital fissure. Direct microsurgical approaches to the CS via the medial trangles of the superior wall and Parkinson tranales of the lateral wall were most important. CONCLUSION: A microanatomical structure of the wall of the CS is provided for direct microsurgical operation to the CS, and the direct microsurgical approaches are discussed.

Adult↗

PubMed1996

[Study on distributions of somatostatin in rat nasal mucosa and trigeminal ganglion].

To explore the regulatory mechanism of the release of neuropeptides in nasal mucosa, the distributions of somatostatin (SOM) and SOMmRNA-immunoreactivities (IR) in cryostat sections of rat nasal mucosa and trigeminal ganglion (TG) cells were investigated using immunohistochemistry (ABC technique) and in situ hybridization histochemistry. The recombinant PSP65 plasmid (400 SOMcDNA) in vitro worked as a plate for the preparation of SOMmRNA single strand (cRNA) probe, which was labelled with digoxigenin. The results showed that neither of these two substances reacted positively in nasal mucosa but positive SOM-IR and SOMmRNA-IR signals were definitely seen in TG cells. In contrast with SOM immunohistochemistry, SOMmRNA-IR positive granules tended to be located in the cytoplasm of TG cells, with a clearer background and a higher resolution rate. The significance of SOMmRNA in TG cells was briefly discussed. It was concluded that SOMmRNA in TG cells might be involved in the regulation of the release of neuropeptides in nasal mucosa.

Animals↗

PubMed1996

Clinical observation on efficacy of electro-acupuncture therapy in hyperplasia of mammary glands and its effect on immunological function.

Based on our work on electro-acupuncture therapy of hyperplasia of mammary glands and in order to observe further the relationship between immunological function and E2 in hyperplasia of mammary glands, we determined the change not only in immunological function before and after electro-acupuncture in 44 in-patients with hyperplasia of mammary glands and having the same menstruation date, but also in electro-acupuncture treated rat hyperplasia of mammary glands model. We found that there was decrease of immunological function in hyperplasia of mammary glands and this function could be remarkably enhanced by electro-acupuncture both in hyperplasia of mammary glands patients and in rat hyperplasia of mammary glands model. The mechanism implies it might be that the inhibitory effect on immunological function exerted by high concentration of E2 was lowered by electro-acupuncture, hence the immunological function was reinforced. The results of this study are important in exploration of both the pathogenesis of this disease and the mechanism of electro-acupuncture, and in reducing the incidence of breast carcinoma.

Adult↗

PubMed1996

[Involvement of the nerve fiber elements in the anterior pituitary in the regulation of ACTH secretion].

While peptidergic nerve fibers have been immunoreactively identified in the adenohypophysis of mammals, the function of these fibers in the regulation of hormone secretion remain unknown. The present work was undertaken to investigate possible modulating effects of these fibers on the secretion of ACTH in the anterior pituitary. Electrical field stimulation (EFS) was applied to excite the nerve terminals in anterior pituitary quarters of male rats under static incubation, and the ACTH level was determined by radioimmunoassay. It was found that the ACTH release from the anterior pituitary was significantly enhanced by EFS (30 mA, 0.5 ms and 10 Hz), which could be significantly decreased by adding TTX or veratridine into the incubation medium. However, TTX failed to inhibit AVP-induced ACTH secretion. Since the dispersed cultured anterior pituitary cells did not respond to the same EFS, it was suggested that there might exist dual modulatory mechanisms on the anterior pituitary hormone secretion.

Adrenocorticotropic Hormone↗

PubMed1996

[The effect of implantation of reconstituted bone xenograft on the production of IL-2].

The present study is designed to investigate any possible effect of implantation of reconstituted bone xenograft (RBX) on the production of IL-2 by T-lymphocytes in female BALB/C mice model. IL-2 levels were elevated in all of the operated groups on the second day, suggesting a stress reaction to trauma caused by operative intervention rather than an immune response to RBX or bBMP. IL-2 production declined significantly on the 7th (P < 0.05) and 14th days (P < 0.01) in RBX and bBMP groups, an evidence of inhibiting effect of RBX on the T-lymphocyte function leading to lowered secretion of IL-2 by spleen T-cells in BALB/C mice. There was no significant difference in lowering of IL-2 secretion between the RBX and bBMP groups as seen when either was compared with the bCB group, suggesting an inhibiting action induced by BMP. The results demonstrated that RBX implantation was not associated with appreciable rejection in that activation, and proliferation of T-cells were inhibited and the secretion of cytokines was lowered resulting in suppressed cellular immunity. We are further convinced that RBX as an immuno-regulating cytokine possesses strong osteo-inductive potential without evoking rejection.

Animals↗

PubMed1996

[Vestibular and auditory functions in Ménière's disease].

This paper is, aiming at understanding disturbances of and correllation between colchear and vestibular functions in Meniere's disease. Auditory and vestibular functions in 121 Meniere cases (70 males and 51 females, age ranging from 19 to 63 years), diagnosed according to the AAO-HNS criteria, were analysed. The results were as follows: 1)There was positive correlation between semicircular canal paresis and hearing impairment. 2) There was statistically significant positive correlation between hearing impairment and the -SP/AP ratio. 3) There was statistically significant correlation between hearing impairment and glycerin test result, the rate of positive result being higher in those with advanced hearing loss than in those with mild loss. 4) There was correlation between the rate of positive glycerin test result and audiogram configuration. The rate with rising audiogram pattern was higher than with that falling pattern (69.0% vs 33.3%). It was also found that ECochG was far more effective than glycerin test in diagnosing Meniere's disease. The physiologic basis and significance of ECochG and glycerin test in Meniere's disease were discussed.

Adult↗

PubMed1996

[Immunohistochemical study on three peptidergic terminals in nasal mucosa in a rat AR model].

To study the density alterations of three peptidergic terminals in nasal mucosa of allergic rhinitis (AR), an exhaustive immunohistochemical sutdy on the changes of substance P (SP), neurokinin A (NKA) and neurokinin B (NKB) in nasal mucosa was carried out in a toluene-2, 4-isocyanate (TDI)-induced rat AR model. The densities of all three tachykininergic terminals in nasal mucosa were significantly increased (P < 0.01) in experimental group as compared with control group. Increased staining, thickening of peptidergic terminals as well as enlargement of varicosities were observed. The increased densities of three tachykininergic terminals (SP, NKA and NKB) in nasal mucosa in rat AR model indicates that tachykinins play an important role in the pathogenesis of AR.

Animals↗

PubMed1995

Structures of genes for two cathelin-associated antimicrobial peptides: prophenin-2 and PR-39.

We characterized genes for prophenin (PF)-2 and PR-39, two cathelin-associated antimicrobial peptides found in porcine leukocytes. Both contained 4 exons and 3 introns and were compact, contiguous and highly homologous. Exons I-III encoded most of their cathelin domains. Exon IV specified the final few cathelin residues, including its conserved C-terminal valine, followed by the mature PR-39 peptide or a PF-2 precursor. The highly conserved 5' flanking sequences of this gene family contained NF-kappa B, IL-6, GM-CSF and NF-1 binding motifs and the introns were unusually conserved. These data suggest that the panoply of porcine cathelin-associated antimicrobial peptides arose relatively recently via gene reduplications and exon shuffling, and that in vivo expression of cathelin-associated antimicrobial peptides may respond to mediators generated early during infection.

Amino Acid Sequence↗

PubMed1995

The structure of porcine protegrin genes.

We cloned the genes of three protegrins, a family of cathelin-associated antimicrobial peptides originally isolated from porcine leukocytes. Each gene comprised 4 exons and 3 introns, wherein Exon I encoded the signal sequence and the first 37 amino acids of cathelin, Exons II and III contained 36 and 24 additional cathelin residues and Exon IV contained the final two cathelin residues followed by the protegrin sequence. This quadripartite gene structure helps explain how structurally diverse antimicrobial peptides can be expressed on common, cathelin-containing precursors. Southern blot probed with an oligonucleotide specific for protegrin genes suggested that several identical or nearly identical protegrin genes were densely clustered in the pig chromosome.

Amino Acid Sequence↗

PubMed1995

Potent inhibitors of the HIV-1 protease with good oral bioavailabilities.

A series of novel pseudo-symmetrical and unsymmetrical inhibitors based on the backbone modification of a peptidomimetic were synthesized and found to be highly potent inhibitors of the HIV-1 protease (IC50 = 2.9 to < 0.5 nM). These compounds also possess good antiviral activity in vitro as measured by inhibition of the cytopathic effect of HIV-1(3B) in MT-4 lymphocytes. Importantly, some of these compounds also have good oral bioavailabilities in rats (F = 30.6% to 100%). One of these compounds 4C, also has good oral bioavailability in beagle dogs and cynomolgus monkeys.

Animals↗

PubMed1995

Prophenin-1, an exceptionally proline-rich antimicrobial peptide from porcine leukocytes.

We purified and characterized an unusual antimicrobial peptide, prophenin-1 (PF-1), from porcine leukocytes. The peptide had a mass of 8,683 and contained 79 residues, including 42 (53.2%) prolines and 15 (19.0%) phenylalanines. Its N-terminal 60 residues consisted of three perfect and three nearly perfect repeats of a decamer, FPPPNFPGPR. Prophenin-1 was encoded on a cathelin-containing precursor and showed substantially more activity against E. coli, a Gram-negative bacterium, than against Listeria monocytogenes, a Gram-positive organism, in vitro.

Amino Acid Sequence↗

PubMed1995

Inorganic cation dependence of putrescine and spermidine transport in human breast cancer cells.

The mechanism of polyamine uptake in mammalian cells is still poorly understood. The role of inorganic cations in polyamine transport was investigated in ZR-75-1 human breast cancer cells. Although strongly temperature dependent, neither putrescine nor spermidine uptake was mediated by a Na+ cotransport mechanism. In fact, Na+ and cholinium competitively inhibited putrescine uptake relative to that measured in a sucrose-based medium. On the other hand, ouabain, H+, Na+, and Ca2+ ionophores, as well as dissipation of the K+ diffusion potential, strongly inhibited polyamine uptake in keeping with a major role of membrane potential in that process. Polyamine transport was inversely dependent on ambient osmolality at near physiological values. Putrescine transport was inhibited by 70% by decreasing extracellular pH from 7.2 to 6.2, whereas spermidine uptake had a more acidic optimum. Deletion of extracellular Ca2+ inhibited putrescine uptake more strongly than chelation of intracellular Ca2+. In fact, bound divalent cations were absolutely required for polyamine transport, as shown after brief chelation of the cell monolayers with EDTA. Either Mn2+, Ca2+, or Mg2+ sustained putrescine uptake activity with high potency (Km = 50-300 microM). Mn2+ was a much stronger activator of spermidine than putrescine uptake, suggesting a specific role for this metal in polyamine transport. Other transition metals (Co2+, Ni2+, Cu2+, and Zn2+) were mixed activators/antagonists of carrier activity, while Sr2+ and Ba2+ were very weak agonists, while not interfering with Ca2+/Mg(2+)-dependent transport. Thus, polyamine uptake in human breast tumor cells is negatively affected by ionic strength and osmolality, and is driven, at least in part, by the membrane potential, but not by the Na+ electrochemical gradient. Moreover, the polyamine carrier, or a tightly coupled accessory component, appears to have a high-affinity binding site for divalent cations, which is essential for the uptake mechanism.

Biological Transport↗

PubMed1995

Hormonal and feedback regulation of putrescine and spermidine transport in human breast cancer cells.

The properties and regulation of the mammalian polyamine transport system are still poorly understood. In estrogen-responsive ZR-75-1 human breast cancer cells, which display low polyamine biosynthetic activity, putrescine and spermidine were internalized with high affinity (Km = 3.7 and 0.5 microM, respectively) via a single class of saturable transporter shared by both substrate types, or via distinct but closely similar carriers. The Vmax, but not the Km of polyamine transport was rapidly and synergistically up-regulated by estrogens and insulin. The steady decay in transport activity observed in hormone-deprived cells was accelerated by retinoic acid. The enhancement of uptake activity resulting from polyamine depletion was amplified 3-fold by estrogens and insulin despite profound growth inhibition, indicating that the cooperative hormonal induction of polyamine transport is dissociated from cell growth status. Polyamine uptake was under feedback inhibition by at least three distinct mechanisms in these cells, namely (i) the induction of a short-lived protein not actively synthesized without ongoing uptake or upon polyamine deletion; (ii) a more latent, protein synthesis-independent "trans-inhibition" mechanism; and (iii) a post-carrier, cycloheximide-sensitive mechanism limiting substrate accumulation. The complexity of these multiple levels of feedback transport inhibition is in keeping with the cytotoxicity of excessive polyamine content.

Biological Transport↗

PubMed1995

A transcription factor controlling development of peripheral sense organs in C. elegans.

The basic-helix-loop-helix (bHLH) proteins constitute a class of transcription factors thought to be important in the control of cell-type determination. These transcription factors are believed to activate the expression of cell-type-specific genes to generate stable differentiated cell types. The expression of bHLH proteins, in turn, is regulated by spatial cues, so that switches in cell type occur in a reproducible pattern. We report here that the lin-32 gene of Caenorhabditis elegans, which encodes a bHLH protein of the Drosophila achaete-scute family of transcription factors, is necessary and in some cells sufficient for specification of the neuroblast cell fate. Similarity in the function and structure of the lin-32 protein (LIN-32) to transcription factors of the achaete-scute gene family in Drosophila and vertebrates implies that this class of transcription factors functioned in a primitive ancestral form to specify neuronal cell fate, supporting the proposition that certain basic mechanisms of cell-type determination have been conserved through metazoan evolution.

Amino Acid Sequence↗

PubMed1995

Histocytological study on the possible mechanism of acetaminophen cataractogenesis in mouse eye.

Ocular toxicity of acetaminophen was investigated in cytochrome P450 inducer-responsive and nonresponsive strains of mice by light and electron microscopy. Acetaminophen injected into C57BL6 mice (responsive strain) that had been pretreated with beta-naphthoflavone produced cataract. The drug did not induce cataract in C57BL6 mice without the pretreatment or in DBA2 mice (nonresponsive strain) similarly pretreated with beta-naphthoflavone. Therefore, induction of cytochrome P450 enzymes that metabolically activate acetaminophen is essential for cataractogenesis. Following acetaminophen injection, tissue damage became noticeable first in the ciliary epithelium and then spread to the iris, corneal endothelium, and lens. The neural retina, retinal pigmented epithelium, and choroid remained unaffected. A close examination of tissues revealed that mitochondria are the primary target of acetaminophen cytotoxicity in ocular tissues affected. The nucleus, endoplasmic reticulum, and other subcellular structures appeared normal. The course of propagation of tissue damage and the almost exclusive damage to mitochondria suggest that the cytotoxic metabolite of acetaminophen is secreted with the aqueous humor by the ciliary epithelium and transported to the lens and that inhibition of mitochondrial energy metabolism, together with other effects of the metabolite, contributes to acetaminophen-induced cataract.

Acetaminophen↗

PubMed1995

Immunocytochemical study of cytochrome P450 (1A1/1A2) induction in murine ocular tissues.

C57BL/6 and DBA/2 mice were injected intraperitoneally with beta-naphthoflavone in corn oil and killed 48 hr later. Control animals received an injection of corn oil. The immunoreactivity of cytochrome P450 1A1/1A2 expressed in different ocular tissues and liver was examined with goat anti-P450 antibody (primary antibody) and gold-conjugated anti-goat antibody (secondary antibody). DBA/2 mice, which are non-responsive to aryl hydrocarbon treatment, showed negligible levels of immunoreactivity toward anti-P450 1A1/1A2 antibody in all ocular tissues, whether or not the animals were treated with beta-naphthoflavone. In responsive C57BL/6 mice, however, the immunoreactivity of the uveal tissues, especially ciliary non-pigmented epithelium, was markedly increased by beta-naphthoflavone treatment. The time course of induction of P450 1A1/1A2 immunoreactivity was very similar for the liver and ciliary non-pigmented epithelium, although the maximum level of immunoreactivity of the ciliary epithelium reached in 48 hr after inducer treatment was about 25% of that of liver. The present results support our previous observations that the P4501A enzyme activities (e.g. aryl hydrocarbon hydroxylase) in the liver and eye of C57BL/6 mice are under the same genetic regulation. Further, this study is the first demonstration of P450 isoform induction in specific ocular tissues of the whole animal.

Animals↗