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T Tang

Publications and source records attributed to T Tang.

At least 73 records · Page 4Linked to original sources
PubMed1995

Temporal differences in the phosphorylation state of pre- and postsynaptic protein kinase C substrates B-50/GAP-43 and neurogranin during long-term potentiation.

The phosphorylation state of two identified neuralspecific protein kinase C substrates (the presynaptic protein B-50 and the postsynaptic protein neurogranin) was monitored after the induction of long term potentiation in the CA1 field of rat hippocampus slices by quantitative immunoprecipitation following 32Pi labeling in the recording chamber. B-50 phosphorylation was increased from 10 to 60 min, but no longer at 90 min after long term potentiation had been induced, neurogranin phosphorylation only at 60 min. Increased phosphorylation was not found when long term potentiation was blocked with the N-methyl-D-aspartate receptor antagonist D-2-amino-5-phosphonovalerate, when only low frequency stimulation was applied or tetanic stimulation failed to induce long term-potentiation. Our data show that both B-50 and neurogranin phosphorylation are increased following the induction of long term potentiation, thus providing strong evidence for pre- and postsynaptic protein kinase C activation during narrow, partially overlapping, time windows after the induction of long term potentiation.

Animals↗
PubMed1995

Anaesthetic management of a patient with a descending thoracic aortic aneurysm and severe bilateral bullous pulmonary parenchymal disease.

The anaesthetic management of the surgical repair of a descending aortic aneurysm in a patient with large, bilateral, pulmonary bullae is described. Anaesthesia for descending aortic surgery normally involves unilateral, positive-pressure ventilation, an option which poses some risk of barotrauma in the presence of bilateral bullae. Patients with bullous disease commonly have severe lung disease and thorough preoperative assessment and preparation are necessary. Intraoperatively, bilateral rupture of the bullae could be catastrophic and preparations should be made for this possibility. In order to diminish this risk, a surgical technique including preemptive collapse of the bulla by minithoracotomy and tube drainage, with use of a bronchial blocker to the affected part of the lung may be used. If rupture occurs, then high frequency jet ventilation may be effective. Use of a double lumen endobronchial tube may be advantageous for patients with either unilateral and bilateral bullae. Anaesthesia for patients with bullae should avoid positive-pressure ventilation and nitrous oxide in order to limit the risk of barotrauma from a ball valve mechanism. In this case, the risk of barotrauma was reduced by performing an inhalational induction of anaesthesia and limiting peak inflation pressures during thoracotomy. It was elected to use positive-pressure ventilation through a double lumen endobronchial tube following chest incision. A high frequency jet ventilator was available but not employed. Anaesthetic management was complicated by the presence of pleural adhesions, surgical approach directly through a bulla, and the requirement for one lung ventilation.

Adult↗
PubMed1995

Opioid-induced increase in [Ca2+]i in ND8-47 neuroblastoma x dorsal root ganglion hybrid cells is mediated through G protein-coupled delta-opioid receptors and desensitized by chronic exposure to opioid.

delta-Receptor agonists induce a concentration-dependent increase in intracellular calcium concentration ([Ca2+]i) in ND8-47 cells by activating dihydropyridine-sensitive Ca2+ channels. The role of G proteins in transducing the opioid effect has been studied. Pretreatment of cells with pertussis toxin (100 ng/ml, 24 h) almost completely blocked [D-Ser2,Leu5]enkephalin-Thr (DSLET)-induced increase in [Ca2+]i. Cholera toxin (10 nM, 24 h) had no effect on DSLET-induced response. Pretreatment of the cells with 1 microM DSLET for 1 h resulted in a 30% inhibition of DSLET-induced increase in [Ca2+]i and a 78% inhibition after exposure for 24 h. After 1 h of exposure to DSLET, there was a decrease in agonist affinity with no significant changes in receptor density. Cells exposed to 1 microM DSLET for 24 h demonstrate a nearly 90% decrease in [3H]diprenorphine binding, with a decrease in affinity for agonist at the remaining binding sites. G protein subunits alpha i2, alpha i3, alpha s, and alpha q were detected in ND8-47 cell membranes by western blot; alpha o and alpha i1 were not present. Chronic DSLET treatment had no significant effect on the quantity of each of the alpha-subunits. These results suggest that the DSLET-induced increase in [Ca2+]i mediated through pertussis toxin-sensitive G proteins (probably Gi2 or Gi3) and the attenuation of this response in chronically treated cells is associated with a relatively rapid reduction in receptor affinity to DSLET and a slow reduction in receptor density.

Calcium↗
PubMed1995

Direct sequencing of SSP-PCR-amplified cDNA to identify new alleles in the DR52-associated DRB1 group: identification of DRB1*1115, DRB1*1117 and DRB1*1319.

Low and high resolution sequence specific oligonucleotide probe hybridization patterns were used to design an approach to direct sequencing of allele specific amplified cDNA. Several PCR amplifications were used to derive overlapping sequence fragments to define complete first domain sequences for a single allele. This method has been used to characterize three new DRB1 alleles in the DR52 family, DRB1*1115, DRB1*1117, and DRB1*1319. All three alleles carry polymorphisms previously observed in other DRB alleles and underscore the importance of utilizing a directed sequencing approach for obtaining unambiguous typing results in matching for bone marrow transplantation between unrelated donor and recipient.

Alleles↗
PubMed1995

Antisense oligodeoxynucleotide to the Gi2 protein alpha subunit sequence inhibits an opioid-induced increase in the intracellular free calcium concentration in ND8-47 neuroblastoma x dorsal root ganglion hybrid cells.

In ND8-47 cells, a neuroblastoma x dorsal root ganglion hybrid cell line, activation of delta-opioid receptors induced an increase in the intracellular free calcium concentration ([Ca2+]i) through dihydropyridine-sensitive calcium channels. This effect was mediated by pertussis toxin-sensitive G proteins. The G protein alpha subunits alpha i2, alpha i3, alpha q, and alpha s were detected using Western blots, whereas alpha o and alpha i1 were not found in ND8-47 cell membranes. To identify the specific G protein alpha subunit(s) responsible for the increase in [Ca2+]i, we treated ND8-47 cells with antisense oligodeoxynucleotides (AS) complementary to the mRNA for each G protein alpha subunit (alpha i2, alpha i3, or alpha s), at a concentration of 10 microM, for up to 6 days and examined their effects on opioid-induced increases in [Ca2+]i and on the levels of G protein alpha subunits. [Ca2+]i was measured in adherent cells using the fluorescent dye fura-2. Treatment of cells with alpha i2-AS (10 microM, for 6 days) resulted in a 73% inhibition of the [D-Ser2,Leu5]-enkephalin-Thr-induced increase in [Ca2+]i. In contrast, pretreatment of cells with alpha i3-AS (10 microM, for 6 days) or alpha s-AS (10 microM, for 6 days) had no effect on the [D-Ser2,Leu5]-enkephalin-Thr-induced responses. Western blots indicated that the levels of alpha i2 were decreased when cells were exposed to alpha i2-AS (10 microM) for 6 days, whereas the levels of alpha i3, alpha s, and alpha q were not affected by this treatment. Treatment of the cells with alpha i3-AS or alpha s-AS for 6 days significantly reduced alpha i3 or alpha s levels, respectively. These results indicate that the opioid-induced increase in [Ca2+]i in ND8-47 cells is mediated by G alpha i2.

Analgesics↗
PubMed1995

[Unstable Jefferson variant atlas fractures: an unrecognized cervical injury].

Nine cases of unstable Jefferson variant atlas fractures were treated with nonoperative external immobilization between 1989 and 1993. All of them were studied by plain films and CT scans. Seven cases had three breaks of the atlas ring. One case had unilateral anterior arch fracture, associated transverse ligament tear and quadriplegia. The other case had Jefferson, Hangman, C3pedicle burst fractures and C3,4dislocation. All of the fractures were unstable or potentially unstable. Despite the abnormal open month view in all cases, the plain films showed minimal abnormalities, requiring CT for definite diagnosis. Follow-up for average of 16 months showed the 7 cases showed the fractures healed with good bone bunion, complete mobility and no residual pain.

Adolescent↗
PubMed1995

[The direct repair of the defect and grafting with single segment reduction fixation system in the treatment of lumbar spondylolysis and spondylolisthesis].

We designed lumbar spondylolysis and spondylolisthesis single segment reduction fixation system according to neural arch measured in the 46 dried specimen. The biomechanical tests showed that its strength is 1.6 times that of Hefti's technique, 2.7 times that of Salib's technique. It used contacted point lamina by lamina hook as fulcrum, through lever and pedicle screw to pull back olisthetic vertebrae. 18 patients were treated with this method. The displacemen rate was 26.67% before operation and 3.38% after operation. The height of disc was 14.94 mm before operation and 17.08 mm after operation. 15 patients were followed up for 12 months. By Henderson standard, excellent result was moted in 13 patients, good in 1 and fair in 1. We conclude that LSRF has good reduction and rigid fixation and it is a new technique for lumbar spondylolysis and spondylolisthesis.

Adult↗
PubMed1994

Augmentation of the immune response to influenza vaccine by acetylsalicylic acid: a clinical trial in a geriatric population.

The purpose of this placebo-controlled, double-blind, randomized trial was to evaluate the efficacy of oral acetylsalicylic acid (ASA), a comparatively safe, inexpensive biological response modifier, as an adjuvant to influenza vaccination in a geriatric population. 281 healthy adults, 65 years or older, received influenza vaccine and were randomized to ASA or placebo. Serum antibody against influenza A/Beijing and B/Panama, influenza antigen-stimulated blastogenesis and antigen-stimulated interleukin-2 production by peripheral blood mononuclear cells in vitro were increased following vaccination. Blastogenic response and interleukin-2 production increased to a similar extent in the two treatment groups. The proportion of participants with a 4-fold rise in specific antibody directed against influenza A/Beijing was greater among ASA recipients (p < 0.05). This difference was more marked in subjects > 75 years old (p < 0.01).

Administration, Oral↗
PubMed1994

Magnetic resonance imaging of the pharynx and larynx.

Imaging of the pharynx and larynx has been a difficult challenge for many years. The advent of magnetic resonance imaging (MRI) with its superior soft tissue contrast resolution and multiplanar capabilities has allowed the imaging specialist to examine these structures with unparalleled precision. The recent developments in MRI can also aid the oncologist, surgeon, and radiation therapist in developing a more comprehensive treatment plan for patients with pharyngeal and laryngeal neoplasms. This article describes the important advances in MRI of the pharynx and larynx.

Humans↗
PubMed1994

[Intracellular recordings and electrophysiological properties of neurons of pancreatic ganglia in vitro].

The work was carried out to investigate electrophysiological properties of neurons of cat intrapancreatic ganglia in vitro by means of intracellular recordings. The mean value of resting membrane potential was -58.5 +/- 8.7 mV (chi +/- s chi, n = 35) with a range from -45 to 72 mV. The mean values of membrane input resistance (Rm), time constant (tau) and capacity (Cm) were 68.6 +/- 5.1M omega, 3.4 +/- 0.2 ms and 50.8 +/- 3.9pF (n = 28), respectively. When depolarizing electrotonic potentials induced by intracellular injection of depolarizing current pulses (0.05-0.5nA, 5ms) reached the threshold potential level, all of the neurons could fire action potentials. The threshold, amplitude, overshoot and duration of spikes were 19.2 +/- 0.5mV, 81.0 +/- 1.7mV, 22.6 +/- 0.9mV and 2.9 +/- 0.1ms (n = 35), respectively. The spike was followed by a prolonged after spike hyperpolarization with amplitude of 20.5 +/- 0.8mV (n = 35). In most of neurons, fast excitatory postsynaptic potentials (f-EPSP) or orthodromic action potentials were recorded during stimulation of nerve trunks attached to the intrapancreatic ganglia. The mean values of amplitude, duration of the f-EPSP and conduction velocity of the nerves were 8.9 +/- 0.7mV, 25.8 +/- 1.9ms and 0.48 +/- 0.04m/s (n = 24), respectively. The ongoing synaptic activity was observed in all of cells. Moreover, f-Epsp, was induced by acetylcholine mediated through nicotinic receptors.

Action Potentials↗
PubMed1994

Opioids acting through delta receptors elicit a transient increase in the intracellular free calcium concentration in dorsal root ganglion-neuroblastoma hybrid ND8-47 cells.

The neuronal cell line ND8-47 (neuroblastoma x dorsal root ganglion neuron hybrid) expressed opioid delta-type receptors. We report opioid-induced changes in cytosolic intracellular free calcium ([Ca++]i) in differentiated ND8-47 cells. Delta-opioid receptor agonists induced a transient (< 2 min) increase in [Ca++]i in a concentration-dependent fashion with the potency order: [D-Ser2,Leu5]enkephalin-Thr (DSLET) > or = deltorphin II > [D-Pen2,5] enkephalin. Their effects were blocked by naloxone (IC50 = 20 nM) and naltrindole (IC50 = 2.5 nM). Selective mu and kappa receptor agonists had no effect on [Ca++]i. The subtype specific delta receptor antagonists, 7-benzylidene naltrexone (delta-1) and naltriben (delta-2), were used to characterize further the subtype of delta receptors mediated by this response. Naltriben was more potent than 7-benzylidene naltrexone in antagonizing the DSLET-induced increase in [Ca++]i. The increase in [Ca++]i induced by DSLET was blocked by nifedipine (1 microM) or verapamil (1 microM), and was not observed in the absence of external calcium. Changes in [Ca++]i also were measured in single ND8-47 cells. The percentage of cells responding to DSLET (1 microM), deltorphin-II (1 microM) and [D-Pen2,5]enkephalin (1 microM) were 86, 84 and 37%, respectively. The results suggest that an increase in [Ca++]i induced by opioids is mediated through opioid delta receptors which can activate dihydropyridine-sensitive Ca++ channels.

Analgesics↗
PubMed1993

ZNC(C)PR affects developmental changes of P46 phosphorylation in rat hippocampus.

Protein phosphorylation has been suggested to be correlated with brain development and with the molecular mechanism of behavioral effects of neuropeptides. The present study reports in vitro endogenous phosphorylation of P46, a membrane-associated protein that is changed during development of the rat hippocampus. This study indicated that the degree of endogenous phosphorylation may be correlated with the establishment of synaptic connections. Interestingly, P46 was proved to be identical to a well-known growth-associated protein B-50/GAP-43 in its identical apparent molecular weight, isoelectric point, phosphorylation dependence, and the cross immunoreaction of monoclonal anti-B-50/GAP-43 antibody and P46. Moreover, neonatal administration of neuropeptide ZNC(C)PR could facilitate the developmental progress of P46 endogenous phosphorylation. It is suggested that the changes in P46 phosphorylation could be involved in the cellular mechanism of ZNC(C)PR behavioral effects on learning.

Animals↗
PubMed1993

Retinoic acid induction of major histocompatibility complex class I genes in NTera-2 embryonal carcinoma cells involves induction of NF-kappa B (p50-p65) and retinoic acid receptor beta-retinoid X receptor beta heterodimers.

Retinoic acid (RA) treatment of human embryonal carcinoma (EC) NTera-2 (NT2) cells induces expression of major histocompatibility complex (MHC) class I and beta-2 microglobulin surface molecules. We found that this induction was accompanied by increased levels of MHC class I mRNA, which was attributable to the activation of the two conserved upstream enhancers, region I (NF-kappa B like) and region II. This activation coincided with the induction of nuclear factor binding activities specific for the two enhancers. Region I binding activity was not present in undifferentiated NT2 cells, but binding of an NF-kappa B heterodimer, p50-p65, was induced following RA treatment. The p50-p65 heterodimer was produced as a result of de novo induction of p50 and p65 mRNAs. Region II binding activity was present in undifferentiated cells at low levels but was greatly augmented by RA treatment because of activation of a nuclear hormone receptor heterodimer composed of the retinoid X receptor (RXR beta) and the RA receptor (RAR beta). The RXR beta-RAR beta heterodimer also bound RA responsive elements present in other genes which are likely to be involved in RA triggering of EC cell differentiation. Furthermore, transfection of p50 and p65 into undifferentiated NT2 cells synergistically activated region I-dependent MHC class I reporter activity. A similar increase in MHC class I reporter activity was demonstrated by cotransfection of RXR beta and RAR beta. These data show that following RA treatment, heterodimers of two transcription factor families are induced to bind to the MHC enhancers, which at least partly accounts for RA induction of MHC class I expression in NT2 EC cells.

Animals↗
PubMed1993

Möbius syndrome: evidence for a vascular etiology.

We report five infants with restricted lateral gaze, facial diplegia, feeding difficulty, and/or respiratory disorders without significant pulmonary disease. Viral studies were negative in all patients. Two children had radiologic findings that included brain-stem hypoplasia and symmetric calcification in the dorsal tectum at the junction of the midbrain and pons. Autopsy of one of these two children demonstrated capillary telangiectasia in the mesencephalon and pons. The other three children had normal computed tomographic (CT) scans. However, their autopsies revealed focal brain-stem necrosis with calcifications but without vascular malformation. We suggest that the capillary malformations in one of our patients directly resulted in a vascular-induced necrosis and the manifestation of Möbius sequence. The similarity of symmetric neuropathologic findings in the three other patients and the CT scan in the one surviving patient suggest focal hemodynamic changes restricted to the posterior circulation, indirectly supporting a vascular theory of embryopathogenesis.

Brain Diseases↗
PubMed1993

Hyperselective posterior rhizotomy in treatment of spasticity of paralytic limbs.

One hundred and eight patients with spasticity of the paralytic limbs were treated successfully with hyperselective posterior rhizotomy (SPR). Of the 108 patients, 100 had cerebral palsy, 2 hemiplegia, 3 sequelae of cerebral injury, 2 paraplegia and 1 multiple sclerosis. Twelve patients received cervical SPR and 96 lumbosacral SPR. Laminectomy is performed to open the dura and to separate the posterior spinal root into several rootlets. The lower threshold rootlets were divided after electrical stimulation. Follow-up for 6 to 30 months showed that the effective rate of reducing spasticity was over 95% and functional improvement rate over 80%.

Adolescent↗
PubMed1993

[3,4-Diaminopyridine-evoked norepinephrine release and B-50 (GAP-43) phosphorylation].

3,4-Diaminopyridine (3,4-DAP 100 mumol.L-1) evoked [3H]norepinephrine ([3H]NE) release in rat hippocampal slices preincubated with [3H]NE and superfused with medium with or without Ca2+. Phorbolester 4 beta-phorbol 12, 13, dibutyrate 1 mumol.L-1) enhanced and polymyxin B (100 mumol.L-1) inhibited the release of [3H]NE under both conditions. The neuron-specific protein B-50 is a major presynaptic substrate of protein kinase C and involved in exocytosis. Using in situ protein phosphorylation analyzed by SDS-PAGE and autoradiography, we observed that B-50 phosphorylation was significantly decreased by 3,4-DAP in the presence of extracellular Ca2+ and completely inhibited by removal of extracellular Ca2+. It was suggested that B-50 phosphorylation was not involved in 3,4-DAP-evoked [3H]NE release.

4-Aminopyridine↗
PubMed1992

Differential role of endothelial function on vasodilator responses in series-arranged arterioles.

Both in vitro and in vivo studies have revealed that removal of vascular endothelial cells abolishes the vasodilation to acetylcholine (Ach) but not sodium nitroprusside (SNP). Differential properties of endothelial cells in the series-arranged arterioles to vasodilator responses have not been studied. In this study, the cheek pouch microcirculation from the golden syrian hamster anesthetized with sodium pentobarbital (6 mg/100 g body wt, ip) was prepared for intravital microscopy. Measurements of lumen diameters of small series-arranged arterioles (2nd- and 4th-order) were made before, during, and after topical microapplication of different doses of either Ach or SNP. After control measurements, a light-dye (L-D) technique utilizing sodium fluorescein (FITC-dextran(150K), 50 mg/100 g body wt, iv) and illuminating a discrete area of the arteriole with 490-nm-wavelength light for 3 (4th) or 10 (2nd) min was used to impair endothelial cell function without damaging vascular smooth muscle cells. Responses to vasoactive substances for both 4th-order (10-20 microns) and second-order (30-50 microns) arterioles were retested. Vasodilatory responses to 10(-7) M Ach and SNP also were tested with and without the presence of NG-monomethyl L-arginine (L-NMMA), an inhibitor of EDRF/NO formation. In the control state, Ach and SNP produced a focal, dose-dependent increase in diameter in all arterioles tested. Endothelial impairment by L-D treatment significantly suppressed the vasodilator response to Ach in 4th- but not 2nd-order arterioles, whereas the SNP response was not significantly affected. Consistent with these observations, L-NMMA treatment significantly attenuated Ach-induced vasodilation in 4th-order arterioles, but it had no effect on 2nd-order arterioles. These studies document further the role of the endothelium in local modulation of arteriolar diameter in response to acetylcholine and demonstrate a differential effect for this response in series-arranged microvessels. Thus, there may be a heterogeneous distribution of endothelial cell functions for modulating vasodilator activity in microvessels.

Acetylcholine↗