[Lumbar intervertebral disc injuries].
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Animals↗
Biomedical subjects
L Jia
Publications and source records attributed to L Jia.
Immobilized IDA-type Cu2+-chelating membrane affinity chromatography for purification of bovine liver catalase.
Cu2+-chelating membrane medium based on iminodiacetate-substituted modified short cotton cellulose was examined to purify bovine liver catalase (BLC) by affinity chromatography. The buffer pH notably affect BLC binding to the Cu2+-chelating membrane adsorbent. The results showed that under the chromatographic conditions chosen, 67.7% recovery of BLC attained with an overall 4.7-fold increase in specific activity in a single step. After purification of BLC, the chelating membrane adsorbent can easily be regenerated by imidazole or EDTA buffer. Different results were obtained by the two regeneration methods: the later is more effective than the former in reviving the purification characters of the chelating membrane adsorbent.
Animals↗
[Determination of calcium in brains of rat by ICP-AES].
This paper reports the determination of calcium in brains of rat by ICP-AES. The recovery rate is 97%, the RSD is 1.16%, and the results are satisfactory. The interference effects of phosphor on the calcium under various operating conditions in ICP-AES were studied.
Animals↗
[Localization of central rhythm generator for tongue movements in sucking--analysis of isolated brainstem-spinal cord preparation from newborn rats].
Localization of the central rhythm generator (CRG) for tongue movements in sucking was studied in in vitro brainstem-spinal cord preparations from newborn rats, using the rhythmical sucking-like activity (RSA) of the hypoglossal nerve (XII) induced by perfusion of N-methyl-D-aspartate (NMDA) as the index of sucking. Sulforhodamine 101 (S 101), a fluorescent dye taken up by neurons in an activity dependent manner, was applied to the preparations which showed only spontaneous inspiratory activity in XII without NMDA application and to those which showed NMDA-induced RSA in XII. In both preparations, the neurons labelled with S 101 were found in the hypoglossal nucleus, facial nucleus, ambiguous nucleus, solitary tract nucleus, trigeminal spinal nucleus, inferior olivary nucleus, gigantocellular, lateral and ventral reticular nuclei. More neurons were labelled more intensely in the latter preparations. The difference was particularly conspicuous in the gigantocellular reticular nucleus, suggesting that it plays an especially important role in central rhythm generation of sucking. The NMDA-induced RSA in XII persisted after removal of the dorsal medulla oblongata, the caudal pons constituting a part of the CRG for mastication, and the trigeminal spinal nucleus relaying afferents in sucking reflex. It was concluded that the CRG for tongue movements in sucking is localized in the ventromedial medulla oblongata.
Animals↗
Polynitrosylated proteins: characterization, bioactivity, and functional consequences.
Chemical modification of proteins is a common theme in their regulation. Nitrosylation of protein sulfhydryl groups has been shown to confer nitric oxide (NO)-like biological activities and to regulate protein functions. Several other nucleophilic side chains -- including those with hydroxyls, amines, and aromatic carbons -- are also potentially susceptible to nitrosative attack. Therefore, we examined the reactivity and functional consequences of nitros(yl)ation at a variety of nucleophilic centers in biological molecules. Chemical analysis and spectroscopic studies show that nitrosation reactions are sustained at sulfur, oxygen, nitrogen, and aromatic carbon centers, with thiols being the most reactive functionality. The exemplary protein, BSA, in the presence of a 1-, 20-, 100-, or 200-fold excess of nitrosating equivalents removes 0.6 +/- 0.2, 3.2 +/- 0.4, 18 +/- 4, and 38 +/- 10, respectively, moles of NO equivalents per mole of BSA from the reaction medium; spectroscopic evidence shows the proportionate formation of a polynitrosylated protein. Analogous reaction of tissue-type plasminogen activator yields comparable NO protein stoichiometries. Disruption of protein tertiary structure by reduction results in the preferential nitrosylation of up to 20 thus-exposed thiol groups. The polynitrosylated proteins exhibit antiplatelet and vasodilator activity that increases with the degree of nitrosation, but S-nitroso derivatives show the greatest NO-related bioactivity. Studies on enzymatic activity of tissue-type plasminogen activator show that polynitrosylation may lead to attenuated function. Moreover, the reactivity of tyrosine residues in proteins raises the possibility that NO could disrupt processes regulated by phosphorylation. Polynitrosylated proteins were found in reaction mixtures containing interferon-gamma/lipopolysaccharide-stimulated macrophages and in tracheal secretions of subjects treated with NO gas, thus suggesting their physiological relevance. In conclusion, multiple sites on proteins are susceptible to attack by nitrogen oxides. Thiol groups are preferentially modified, supporting the notion that S-nitrosylation can serve to regulate protein function. Nitrosation reactions sustained at additional nucleophilic centers may have (patho)physiological significance and suggest a facile route by which abundant NO bioactivity can be delivered to a biological system, with specificity dictated by protein substrate.
Animals↗
S-nitrosohaemoglobin: a dynamic activity of blood involved in vascular control.
A dynamic cycle exists in which haemoglobin is S-nitrosylated in the lung when red blood cells are oxygenated, and the NO group is released during arterial-venous transit. The vasoactivity of S-nitrosohaemoglobin is promoted by the erythrocytic export of S-nitrosothiols. These findings highlight newly discovered allosteric and electronic properties of haemoglobin that appear to be involved in the control of blood pressure and which may facilitate efficient delivery of oxygen to tissues. The role of S-nitrosohaemoglobin in the transduction of NO-related activities may have therapeutic applications.
Allosteric Regulation↗
Increased activity and sensitivity of mitochondrial respiratory enzymes to tumor necrosis factor alpha-mediated inhibition is associated with increased cytotoxicity in drug-resistant leukemic cell lines.
The drug-resistant leukemic cell lines, CEM/VLB100 and K/DAU600, are more sensitive to tumor necrosis factor alpha (TNFalpha)-mediated cytotoxicity compared with their parental cell lines, CCRF-CEM and K562 cl.6. Drug-resistant leukemic cell lines have more active mitochondrial function, which is associated with a greater susceptibility to TNFalpha-induced respiratory inhibition. TNFalpha blocked electron transfer at three sites, NADH dehydrogenase (complex I), succinate dehydrogenase (complex II), and cytochrome c oxidase (complex IV). Respiratory rate and electron transport chain enzyme activities were significantly inhibited in the drug-resistant, TNF-sensitive cell lines. Respiratory inhibition preceded cell death by at least 5 to 8 hours. The respiratory failure was not compensated for by appropriate up-regulation of the glycolytic pathway. Increasing mitochondrial respiratory rate and enzyme activities by long-term culture with 2 mmol/L adenosine 5'-diphosphate (ADP) and Pi sensitized both drug-sensitive and drug-resistant cells to TNFalpha-induced cytolysis. Intramitochondrial free radicals generated by paraquat only had a limited and delayed effect on respiratory inhibition and cytolysis in comparison with the effect of TNFalpha. We conclude that TNFalpha-induced cytotoxicity in leukemic cells is, at least in part, mediated by inhibition of mitochondrial respiration. Free radical generation by TNFalpha may not directly lead to the observed inhibition of the mitochondrial electron transport and other mechanisms must be involved.
Adenosine Diphosphate↗
Modulation of surface TNF expression by human leukaemic cells alters their sensitivity to exogenous TNF.
In this study, U937 leukaemic cells underwent apoptotic cell death following exposure to TNF. Pre-incubation of cells for 48 h with VitD(3) (10(-8)M) induced resistance to TNF, whereas incubation with tau-IFN or GM-CSF increased susceptibility to TNF. Resistance to exogenous TNF (exTNF) following culture with VitD(3) was associated with increased expression of endogenous TNF (enTNF). The TNF inhibitors pentoxifylline(PTF) and dichloroisocoumarin (DCI) inhibited TNF synthesis by U937 cells and abrogated the increase in resistance to TNF seen with VitD(3). The tau-IFN increased TNF expression, whereas GM-CSF had little effect. The data show that the sensitivity of leukaemic cells to exTNF can be modulated by cytokines. The protective effect of VitD(3) is mediated in part by directly upregulating enTNF synthesis.
Alkaloids↗
[Effect of platelet activating factor receptor at spinal cord neurocyte membrane on secondary damage after spinal cord injury].
OBJECTIVE: To investigate the effects of platelet activating factor (PAF) receptor and its antagonist on secondary damage after spinal cord injury. METHODS: We extracted spinal cord neurocyte membrane protein in cats by improved Domigo method. The specific binding sites of PAF were measured by 3H-PAF radioligand binding test. RESULTS: There were both high affinity binding sites and low affinity binding sites of PAF on spinal cord neurocyte membrane. The Kd1, Bmax1, Kd2 and Bmax2 of PAF receptor on spinal cord neurocyte membrane at 2, 6 hours and 1 week after trauma significantly decreased as compared to sham-operated control group (P < 0.01). PAF receptor antagonist BN52021 could reduced water content and Even's blue content of injured spinal cord tissue, also improve pathological change of spinal cord tissue after trauma. CONCLUSIONS: PAF receptor plays an important role in inducing pathophysiological process of secondary damage after trauma. PAF receptor antagonist can effectively prevent and treat secondary damage after trauma.
Animals↗
Role of facet asymmetry in lumbar spine disorders.
The correlation between facet joint asymmetry and disorders of the lumbar spine was analyzed in a study of plain radiographs, computed tomograms and magnetic resonance images from 76 normal subjects and 173 patients who underwent lumbar surgery. Of 76 normal controls who were studied by means of plain radiographs, only 21 (27.6%) had facet asymmetry at the level of L4-5 or L5-S1, while 84 (48.6%) of 173 patients who were studied with plain radiographs, and partially with CT or MRI, were noted to have facet asymmetry. The difference was highly significant (P < 0.01). This study supports the etiologic significance of facet asymmetry in lumbar disorders.
Adult↗
[Subclinical hepatic encephalopathy].
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Evoked Potentials↗
[Os odontoideum].
Seventeen patients who had os odontoideum were reviewed. Among them occipito-cervical fusion was performed upon 12 patients with atlanto-axial instability. All of them achieved fusion. The patients were followed up for 2 to 16 years and satisfactory results were demonstrated. We consider that surgical treatment is indicated when os odontoideum is combined with atlanto-axial instability.
Adolescent↗
Two-peak photoluminescence and light-emitting mechanism of porous silicon.
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Journal Article↗
NMDA-induced rhythmical activity in XII nerve of isolated CNS from newborn rats.
We tried to induce rhythmical oro-facial motor activities in an isolated brain stem-spinal cord preparation from newborn rats. Neural activities were monitored from the hypoglossal nerve (XII N) and the ventral roots of the cervical cord. Bath application of N-methyl-D-aspartate (NMDA) as well as glutamate induced rhythmical burst activity in XII N distinct from and much faster than respiratory rhythm. This NMDA-induced rhythmical activity was blocked by simultaneous application of 2-amino-5-phosphonovalerate (AP5). The results demonstrate that NMDA receptor activation can induce rhythmical XII N activity different from respiration in an isolated mammalian CNS. This preparation will be useful for the investigation of neural mechanisms underlying the central generation of food ingestive movements.
Animals↗
TNF-mediated killing of human leukaemic cells: effects of endogenous antioxidant levels and TNF alpha expression in leukaemic cell lines.
Using the human erythroleukaemic cell line K562 cl.6 and its daunorubicin-resistant subline K/DAU600, and the human T-lymphoblastic leukaemic cell line CCRF-CEM and its vinblastine-resistant subline CEM/VLB100, we have shown that the drug-resistant cell lines were more sensitive to cytotoxicity induced by tumour necrosis factor-alpha (TNF alpha). Drug-resistant cell lines showed increased activities of copper/zinc superoxide dismutase (Cu/ZnSOD) and catalase compared with their parental drug-sensitive cell lines. However, the greater susceptibility of drug-resistant cells to TNF alpha cytotoxicity was, in part, related to their decreased activities of manganese superoxide dismutase (MnSOD). Persistence of this differential sensitivity when MnSOD is inhibited by sodium nitroprusside (SNP) suggests that the greater susceptibility of drug-resistant cells to TNF alpha was not entirely due to their decreased level of MnSOD activity. K562 cl.6 and K/DAU600, which were more resistant to TNF alpha, both expressed greater levels of endogenous plasma membrane-bound TNF alpha than the CCRF-CEM cell line. All cell lines examined were (more or less) equal in susceptibility to the cytolytic effect of exogenous O2-. generated by xanthine/xanthine oxidase. These results demonstrate that both MnSOD and endogenous TNF alpha play a role in protecting leukaemic cells against TNF alpha cytotoxicity, but there is an unknown mechanism that causes drug-resistant cells to be more susceptible to TNF alpha cytotoxicity.
Catalase↗
Cruciate paralysis caused by injury of the upper cervical spine.
Cruciate paralysis is an uncommon injury to the cervicomedullary junction. Five patients with injuries of the upper cervical spine and the clinical manifestation of cruciate paralysis are presented. This injury pattern is characterized by bilateral upper extremity paralysis, with minimal or no lower extremity involvement. The neuroanatomic basis and the diagnosis of this clinical entity are discussed, and the related reports in the literature are reviewed.
Adult↗
[The effect of qing guang kang on the metabolism of retinal ganglionic cells in rats after artificial acute high intraocular pressure].
A modified cytochrome oxidase (CO) histochemical and computer image techniques were used to examine the effect of Qing Guang Kang (QGK) injection on the metabolism of rat retinas after artificial acute high intraocular pressure. The results show that 75% of the average arterial blood pressure as the perfusing pressure of the anterior chamber of rats can lead to the decrease of numbers of CO active retinal ganglionic cells and their grey values. QGK possess the protective and/or improving effects on the CO active retinal ganglionic cells of rat under artificial acute high intraocular pressure. In the study, the data of density and the grey value of CO active ganglionic cells in the experimental models with QGK injection are significantly different from those of the control group (P < 0.05).
Animals↗
[Image and clinical correlative studies on cervical spinal canal stenosis].
Clinical finding, X-ray and MR imagings in 47 patients who underwent operation for degenerative cervical stenosis were correalatively studied. JOA score was used for evaluation and it varied from 6 to 14 points, with an average of 10.13 points. All Torg ratios were smaller than normal value and that of C4 was the smallest. The reserve space, sagittal diameter of spinal cord decreased, especially in the diseased segments. Sagittal diameter of spinal cord showed on T2 weighted imaging and Torg ratio were in good correlation with JOA score (P < 0.01, r = 0.4815, r = 0.0993), MRI being superior to X-ray (P < 0.01). The MRI characteristic changes of degenerative cervical stenosis were subarachnoid space decrease or vanish, compression deformation of spinal cord and abnormal signal in spinal cord. MRI classification was established according to the segments involved, compression direction. compression degree and abnormal changes in spinal cord, can indicate clinical changes and guide diagnosis and operation.
Adult↗