A case of wide-complex tachycardia.
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Bundle of His↗
Biomedical subjects
T Wang
Publications and source records attributed to T Wang.
Bcl-2 oncoprotein is widespread in lymphoid tissue and lymphomas but its differential expression in benign versus malignant follicles and monocytoid B-cell proliferations is of diagnostic value.
The distribution of Bcl-2 oncoprotein was studied immunohistochemically in formaldehyde-fixed and paraffin-embedded reactive and neoplastic lymphoid tissue. The potential of Bcl-2 for the differential diagnosis of follicular lesions was emphasized, and the results on follicular lesions were correlated with those of polymerase chain reaction (PCR) assay of the immunoglobulin heavy chain gene rearrangement. In hyperplastic lymphoid tissue, Bcl-2 reactivity was widespread, including germinal center surroundings, scattered cells within the germinal centers, and the T-cell areas in general. Distinctively negative lymphoid populations included the majority of germinal center cells, and the negative staining pattern was maintained in cases of florid hyperplasia. In contrast, follicular lymphoma cells were consistently Bcl-2 positive. The immunohistochemical Bcl-2 reactivity of lymphoma follicles correlated with the clonal PCR amplification pattern of the immunoglobulin heavy chain gene; all Bcl-2-negative hyperplasias revealed a non-clonal pattern. Clusters of monocytoid B cells were Bcl-2 negative, whereas monocytoid B-cell lymphomas and closely related MALT lymphomas were positive. All other small cell non-Hodgkin's lymphomas of B-cell types showed nearly uniform Bcl-2 reactivity, whereas large cell B-cell lymphomas were variably positive (74%). In Hodgkin's cells, Bcl-2 reactivity was seen in the neoplastic populations of most cases of nodular sclerosis and mixed cellularity types, whereas the L&H and Reed-Sternberg cells in lymphocyte predominance Hodgkin's disease were negative in most cases. Bcl-2 immunohistochemistry thus appears very valuable in the differential diagnosis of follicular hyperplasia and neoplasia, and it may help to distinguish between reactive and neoplastic monocytoid B cells. However, Bcl-2 immunohistochemistry is not useful in the subtyping of B-cell lymphomas.
Hodgkin Disease↗
Antifreeze glycoproteins promote intracellular freezing of rat cardiomyocytes at high subzero temperatures.
Despite recent reports that antifreeze glycoproteins (AFGPs) protect mammalian cells during low-temperature preservation, T. Wang, Q. Zhu, X. Yang, J. R. Layne, and A. L. DeVries (Cryobiology 31: 185-192, 1994) reported that AFGPs failed to protect rat hearts during freezing. Rather, the presence of AFGPs exacerbated cardiac damage after freezing. This study examined the effects of freezing (-4 degrees C) in the presence of AFGPs at the cellular level with the use of cryomicroscopy. Large, blunt ice crystals formed in the solutions without AFGPs and excluded most cardiomyocytes from the plane of ice formation. After thawing, cells appeared similar in morphology to unfrozen cells. Ice in 0.5 mg/ml AFGP solution was more dendritic and prismatic than ice formed in the absence of AFGPs. On thawing, many cells exhibited spontaneous contraction, resulting in cell death. Spicular ice formed rapidly in the 10 mg/ml AFGP solution. These needlelike ice crystals appeared to penetrate the cardiomyocytes, resulting in intracellular freezing followed by cell lysis. These AFGP-induced changes in ice crystal structure may account for the injury observed in whole heart and cardiomyocyte experiments.
Animals↗
Stimulation of chloride transport by cAMP in rat proximal tubules.
We have previously demonstrated that formate and oxalate stimulate transcellular Cl- absorption (JCl) in the rat proximal tubule by a mechanism involving DIDS-sensitive anion exchange across the luminal membrane and diphenylamine-2-carboxylate (DPC)-sensitive Cl- channels in the basolateral membrane. Recent evidence indicates cAMP activation of Cl- channels in apical and basolateral membranes of proximal tubule cells. We therefore tested the effect of cAMP on Cl- and fluid transport in rat proximal tubule studied by luminal and capillary microperfusion in situ. The luminal perfusate contained 5 mM HCO3- and 145 mM Cl-, and the capillary perfusate contained 25 mM HCO3- and 110 mM Cl-, simulating conditions in the late proximal tubule. Addition of 0.5 mM dibutyryl cAMP markedly stimulated fluid absorption (Jv) and JCl. Similar effects resulted from addition of forskolin (10 microM) to stimulate cAMP production. The increments in Jv and JCl due to dibutyryl cAMP were abolished when the Cl- channel blocker DPC (200 microM) was added to the capillary perfusate but not when it was added to the lumen. The increments in Jv and JCl due to dibutyryl cAMP were unaffected by luminal DIDS (100 microM), which abolishes the increments in Jv and JCl induced by addition of oxalate. In contrast, the increments in Jv and JCl due to dibutyryl cAMP were abolished by luminal 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB; 10 microM), another Cl- channel blocker. Luminal NPPB had no effect on baseline Jv and JCl nor on the increments in Jv and JCl induced by addition of oxalate.(ABSTRACT TRUNCATED AT 250 WORDS)
Absorption↗
[Effect of dentin organic and inorganic substances on the curing time of bonding resin].
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Collagen↗
Suppression of tumorigenesis by transcription units expressing the antisense E6 and E7 messenger RNA (mRNA) for the transforming proteins of the human papilloma virus and the sense mRNA for the retinoblastoma gene in cervical carcinoma cells.
Human cervical carcinoma cell lines that harbor human papilloma virus (HPV) have been reported to express HPV E6 and E7 proteins at least in the beginning stages if not at all stages of the disease. The HPV E6 and E7 proteins bind to and inactivate the products of the p53 and retinoblastoma (Rb) tumor suppressor genes, which thereby allow the cervical carcinoma cells to circumvent the action of these tumor suppressor genes. We observed that the introduction of the antisense HPV 18 E6 and E7 sequences, as well as a sense cDNA for the human wild-type Rb gene into a human cervical carcinoma cell line (HeLa), which is positive for the HPV 18 provirus, decreased the in vitro and in vivo growth rate of the transfected cells if both antisense transcripts for the HPV 18 E6 and E7 and sense transcripts for human Rb were expressed. In addition, overexpression of a complementary DNA (cDNA) for the Rb messenger RNA was sufficient to slow the proliferation of HeLa cells, and the level of Rb cDNA expression was correlated with the degree to which the rate of growth of the tumor was slowed. The results of our experiments show that the presence of HPV E6 and E7 proteins and the resultant inactivation of Rb in cervical carcinoma cells contributes to the neoplastic phenotype even in highly evolved cervical carcinoma cell lines such as HeLa, which have been derived from a cervical carcinoma patient at an advanced stage of the disease process. These data suggest that the HPV proteins play a role not only at the beginning of cervical cancer, but also at advanced stages of this disease. These experiments may lead to genetic approaches to the control of this disease that involve antisense sequences that downregulate the E6 and E7 genes or lead to expression of the Rb gene.
Animals↗
Neurotrophins promote maturation of developing neuromuscular synapses.
Although the effects of neurotrophins on survival and differentiation of various neuronal populations have been well studied, little is known about their role in synaptic development and function. We have investigated the long-term effects of neurotrophins in the maturation of neuromuscular synapses in Xenopus nerve-muscle cocultures. BDNF and NT-3, but not NGF, elicited significant changes in several properties of spontaneous synaptic currents (SSCs), indicative of more mature synapses. Most synapses treated by the neurotrophins exhibited a bell-shaped distribution of SSC amplitudes, which reflects mature quantal secretion. The neurotrophins also potentiated the efficacy and reliability of stimulus-induced synaptic transmission. Moreover, BDNF and NT-3 increased the levels of the synaptic vesicle proteins, synaptophysin, and synapsin 1 in the spinal neurons. The number of varicosities per neuron also showed a significant increase after neurotrophin treatment. The effects of the neurotrophins appear to be mediated by the Trk family of receptor tyrosine kinases, primarily through a presynaptic mechanism. These results suggest that BDNF and NT-3 promote functional maturation of synapses.
Acetylcholine↗
[Clinical use of conservative surgery in hypopharyngeal carcinomas].
Fifty-one cases of hypopharyngeal carcinoma treated with conservative hypopharyngectomy (CH) and 29 cases of total larygectomy hypopharyngectomy (the Control) were retrospectively analyzed. In patients with CH, laryngeal function restored completely in 36 cases, and partially in 15. Severe complication rate (including graft necrosis, fistulae and structure) was 23.5% (12/51). Successful deglutition rate was 98%; mean resumption of oral intake was 29 days (10-150 days) and mean hospitalization 40 days (16-160 days). Three-year survival rate was 58.8% and 5-year survival rate 49.0% (25/51). No significant difference was found between the patients with CH and the control in the aspects of severe complication rate, successful deglutition rate, mean resumption of oral intake, mean hospitalization and 5-year survival rate (P > 0.05).
Adult↗
Mixed model analysis of DNA sequence evolution.
Nucleotides in a DNA sequence may be changing at different rates, because they are located in different structural and functional regions of the gene, and are thus subject to different mutational pressures or selective restrictions. Knowledge of substitution rates at specific sites is important for understanding the forces and mechanisms that have shaped the evolution of the DNA sequences. The gamma distribution has previously been proposed to model such rate variation among nucleotide sites. Based on mixed model methodology we present in this paper a method for predicting substitution rates at nucleotide sites by using homologous DNA sequences. The predictor is unbiased and "best" in the sense that it minimizes the mean squared error and maximizes the correlation between the predictor and the true value. It is also quite robust to errors in estimates of parameters in the model. A numerical example is given, with guidelines for the practical use of the approach. The most influential factor affecting the accuracy of prediction is the number of sequences; to get a correlation of over .7 between the predictor and the true value, about six to seven sequences are needed, depending on the overall similarity of the sequences.
Animals↗
Laryngotracheal flap for reconstruction of hypopharynx and upper esophagus after resection of advanced pyriform sinus cancer.
Reconstruction of the hypopharynx and upper esophagus after resection of advanced pyriform sinus cancer, is usually complicated and time-consuming. Laryngotracheal flap was used in hypopharyngoesophageal reconstruction for 26 elderly patients with advanced pyriform sinus cancer Pharyngocutaneous fistula developed in 5 patients and healed spontaneously without further surgery. Full diet was resumed in all the patients. The surgical technique and its advantages and disadvantages are discussed. The laryngotracheal flap in the reconstruction of hypopharyngoesophageal defect for elderly patients is a procedure of choice.
Aged↗
SNC 80, a selective, nonpeptidic and systemically active opioid delta agonist.
The present study has investigated the pharmacology of SNC 80, a nonpeptidic ligand proposed to be a selective delta agonist in vitro and in vivo. SNC 80 was potent in producing inhibition of electrically induced contractions of mouse vas deferens, but not in inhibiting contractions of the guinea pig isolated ileum (IC50 values of 2.73 nM and 5457 nM, respectively). The delta selective antagonist ICI 174,864 (1 microM) and the mu selective antagonist CTAP (1 microM) produced 236- and 1.9-fold increases, respectively, in the SNC 80 IC50 value in the mouse vas deferens. SNC 80 preferentially competed against sites labeled by [3H]naltrindole (delta receptors) rather than against those labeled by [3H]DAMGO (mu receptors) or [3H]U69, 593 kappa receptors) in mouse whole-brain assays. The ratios of the calculated Ki values for SNC 80 at mu/delta and kappa/delta sites were 495- and 248-fold, respectively, which indicates a significant degree of delta selectivity for this compound in radioligand binding assays. SNC 80 produced dose- and time-related antinociception in the mouse warm-water tail-flick test after i.c.v., i.th. and i.p. administration. The calculated A50 values (and 95% C.I.) for SNC 80 administered i.c.v., i.th. and i.p. were 104.9 (63.7-172.7) nmol, 69 (51.8-92.1) nmol and 57 (44.5-73.1) mg/kg, respectively. The i.c.v. administration of SNC 80 also produced dose- and time-related antinociception in the hot-plate test, with a calculated A50 value (and 95% C.I.) of 91.9 (60.3-140.0) nmol.(ABSTRACT TRUNCATED AT 250 WORDS)
Analgesics↗
[Dynamic cardiomyoplasty: first successful clinical case in China].
A 35-year-old man with chronic heart failure (NYHA Class III) caused by dilated cardiopathy was selected for dynamic cardiomyoplasty. The procedures were completed in one stage. The left latissimus dorsi muscle was mobilized and wrapped around the heart. A set of medtronic cardiomyostimulator system (A Medtronic Model SP 1005A Cardiomyostimulator, two Medtronic Model SP 5528 intramuscular leads, and two medtronic Model 5701-35 Cardiac screw-in leads) was implanted. The postoperative sequential progressive skeletal muscle electrostimulation was started two weeks after cardiomyoplasty. The final electrostimulated parameters were: 6 pulses, amplitude 2.75 V, synchronization delay 75 ms, pulse width 210 us, synchronization delay 75 ms, pulse width 210 us, synchronization ratio 2:1, frequency 30 Hz, stimulation duration 185 ms. The patient recovered very well. After four months, patient's status improved to NYHA Class I. Echocardiography, MUGA, and catheterization studies showed a significant improvement in hemodynamic parameters (MUGA LVEF increased from 15% to 24%, SVI increased from 21.7 ml/beat/m2 to 50.6 ml/beat/m2: CI increased from 2.699 L/min/m2 to 3.59 L/min/m2.
Adult↗
[Current status and perspective of researches in cardiovascular pathology].
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Animals↗
Effects of a novel KATP channel blocker on renal tubule function and K channel activity.
ATP-sensitive potassium channels (KATP) modulate Na, K and Cl reabsorption in the thick ascending limb of the loop of Henle and K secretion in the cortical collecting tubule. Inhibition of potassium recycling in the apical membrane of the thick ascending limb of the loop of Henle interferes with sodium reabsorption and suppression of the apical potassium conductance in principal cells of the cortical collecting tubule and reduces potassium secretion. Both potassium recycling and potassium secretion depend critically on the activity of KATP, and recent studies indicate that the sulfonylurea compound glyburide, a known KATP channel blocker, is diuretic but does not produce kaliuresis.
Adamantane↗
Enhanced expression of TGF-beta 1 by peritoneal macrophages in CAPD patients.
Peritoneal macrophages are the predominant cells in peritoneal dialysate. To clarify the role of the macrophage in fibrosis of the peritoneum in long-term continuous ambulatory peritoneal dialysis (CAPD) patients, we studied the transforming growth factor beta (TGF-beta 1) mRNA expression by peritoneal macrophages from peritoneal dialysis patients. Macrophages were obtained when the catheter was inserted and one month later. TGF-beta 1 mRNA was measured by slot-blot hybridization using a cDNA probe. The result was that TGF-beta 1 expression was significantly higher in macrophages from peritoneal dialysate than that of macrophages obtained during catheter insertion. This suggests that peritoneal macrophages play a role in the pathogenesis of fibrosis of peritoneum in peritoneal dialysis patients. It also suggests that peritoneal macrophages in dialysate have been somewhat activated.
Autoradiography↗
Influence of peritoneal dialysis on the progression of chronic renal failure.
To determine whether an early start of peritoneal dialysis is beneficial to the preservation of residual renal function, we studied the effect of peritoneal dialysis on the progression of glomerular sclerosis in subtotal nephrectomy rats. Four weeks after subtotal nephrectomy, Wistar rats were treated with peritoneal dialysis (PD) (through a silicone catheter, two exchanges per day with 20 mL 1.5% dextrose solution per exchange for 8 weeks, n = 10). Then the kidneys were checked. The sclerosis index was significantly lower in the PD group than that of the control group, which was 1.12 +/- 0.13, 1.64 +/- 0.19, respectively (p < 0.05). This suggests that peritoneal dialysis may suppress the progression of chronic renal failure. An early start of PD may benefit the preservation of renal function in uremic patients.
Animals↗
Effect of glucose on TGF-beta 1 expression in peritoneal mesothelial cells.
The peritoneum's response to peritoneal dialysis is a complex and poorly understood process that can result in fibrosis. The transforming growth factor beta(TGF-beta 1) plays a central role in regulating tissue repair and remodeling after injury. To determine the role of mesothelial cells during peritoneal dialysis in the alteration of the peritoneum, we studied the effect of glucose on TGF-beta 1 expression by mesothelial cells. Human mesothelial cells were cultured in serum-free DMEM with different glucose concentrations for 48 hours. TGF-beta 1 messenger (mRNA) was measured by slot-blot hybridization using a TGF-beta 1 cDNA probe. The result was that glucose stimulates TGF-beta 1 mRNA expression in a dose-dependent way. The expression was more profound in high glucose concentrations. This suggests that TGF-beta 1 mRNA may overexpress by mesothelial cells due to the procedure of dialysis, which may be the most important mechanism of alteration of the peritoneum during peritoneal dialysis.
Autoradiography↗
[Studies on mode of human infection with Echinochasmus liliputanus].
Epidemiological survey and experimental studies on the mode of human infection with Echinochasmus liliputanus were carried out in Chenqiaozhou Village, Hexian County, Anhui Province in 1992. The results showed that humans could be infected through drinking unboiled water containing E.liliputanus cercaria or eating raw fish containing the metacercaria. The infection rates of E. liliputanus were 1.5% in the inhabitants who did not drink raw water, and 20.1% in those who used to drink raw water. It was only the cercaria, not the metacercaria that was detected in the water from ponds of this village. None of the investigated inhabitants ate uncooked fish. The results indicated that drinking raw water containing E.liliputanus cercaria was a major way through which a humans were infected and eating food containing the metacercaria was a minor mode of human infection.
Animals↗