Ibuprofen, indomethacin, and high-dose aspirin, but not low-dose aspirin or imidazole, inhibit CGRP elevations in plasma during endotoxicosis.
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Animals↗
Biomedical subjects
L Yang
Publications and source records attributed to L Yang.
Risk of lung cancer among cigarette and pipe smokers in southern China.
Studies in Shanghai and in north-east China indicate that cigarette smoking is a major contributor to the high rates of lung cancer in those areas, but doubts persist regarding the influence of cigarette use on lung cancer rates in other areas of China. In addition, the risk of lung cancer associated with other methods of tobacco consumption--in particular, the use of bamboo water-pipes and long-stem pipes--is uncertain. A population-based case-control study of 427 male lung cancer patients residing in a mining area of Southern China and 1,011 controls was carried out to address this and other issues. Of these patients, 63% smoked cigarettes and (water and long-stem) pipes; 17% and 14% smoked only cigarettes or pipes, respectively; and 6% did not smoke. Compared to non-smokers, smokers of cigarettes only, smokers of pipes only and mixed smokers were at increased risk; OR = 2.6 (95% CI 1.1-6.2), 1.8 (95% CI 0.8-4.2) and 4.1 (95% CI 2.3-9.2), respectively. Risk increased with duration of tobacco use; however, the rate of increase with years of cigarette use was significantly greater than for years of pipe use (p = 0.03). In addition, risks increased 8-fold in the highest quartile of number of cigarettes per day compared to non-cigarette smokers vs. 2.3-fold for the highest quartile of number of liang (50 g) smoked per month compared to non-pipe-smokers; the trends in the ORs differed significantly (p less than 0.001). Results suggest that, in this area of China, tobacco use is an important cause of lung cancer, and that smoking cigarettes may be more deleterious than smoking pipes (primarily water pipes).
Adult↗
Hepatocyte growth factor induces calcium mobilization and inositol phosphate production in rat hepatocytes.
The effects of hepatocyte growth factor (HGF) on intracellular Ca2+ mobilization were studied using fura-2-loaded single rat hepatocytes. Hepatocytes microperfused with different amounts of HGF responded with a rapid concentration-dependent rise in the cytosolic free Ca2+ concentration with a maximum increase of 142% at 80 ng/ml of HGF. The lag period of the Ca2+ response was decreased with increasing HGF concentrations, being 64 +/- 12 s, 42 +/- 6 s, and 14 +/- 2 s, respectively, with 8, 20, and 80 ng/ml of HGF. The detailed pattern of Ca2+ transients, however, was variable. Out of 16 cells tested using 20 ng/ml of HGF, 68% showed sustained oscillatory responses, whereas other cells showed a sustained increase in the cytosolic-free Ca2+ upon exposure to HGF, which was dependent on the presence of extracellular Ca2+. HGF also induced Ca2+ entry across the plasma membrane. Mobilization of Ca2+ by HGF was accompanied by a rapid accumulation of inositol 1,4,5-trisphosphate (Ins 1,4,5-P3). The effects of HGF and epidermal growth factor (EGF) were comparable and partly additive for Ins 1,4,5-P3 production and for the sustained phase of Ca2+ mobilization. Preincubation of cells with 10 microM of genistein to inhibit protein tyrosine kinases abolished the HGF-induced Ca2+ response and also inhibited HGF-induced Ins 1,4,5-P3 production in rat liver cells. These data indicate that early events in the signal transduction pathways mediated by HGF and EGF have in common the requirements for tyrosine kinase activity, Ins 1,4,5-P3 production, and Ca2+ mobilization.
Animals↗
A distributed model of exchange processes within the osteon.
In order to understand various exchange processes within the osteon, a mathematical model to describe the system has been developed which allows for concentration gradients in the axial and radial directions as well as cellular consumption and binding to bone surface. The normal values for the model parameter are discussed and the effects of the model parameters on the behaviour of the model are investigated. This model supports the idea that diffusion alone may be an inefficient mechanism in transport between blood and osteocytes.
Biological Transport↗
Steroidal constituents from Amalocalyx yunnanesis.
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Carbohydrate Sequence↗
The roles of macrophage (M phi) and PGE-2 in postburn immunosuppression.
Postburn immunosuppression in mice with full skin thickness burns was assessed after Con A stimulation of splenic lymphocytes. The immunosuppression was detected within 24 h of injury and was maximal 3-7 days later. Such lymphocyte proliferation was enhanced by depletion of adherent cells (M phi) in burned mice and could be depressed in normal mice by injection of these adherent cells from burned mice. These results suggest the presence of M phi s with a suppressor function. No difference in spontaneous blastogenic transformation (SBT) of spleen cells between the burned and normal mice was found, but after removal of the M phi s the SBT of spleen cells of burned mice became significantly elevated. Hence both M phi and lymphocytes in mouse spleen cells were activated after severe thermal injury.
Animals↗
Demethylation of satellite I DNA during senescence of bovine adrenocortical cells in culture.
Over the finite proliferative life span of cultured bovine adrenocortical cells, satellite I DNA shows a progressive and extensive loss of methylation at CCGG sites. This was shown by Southern blotting after digestion with the methylation-sensitive enzyme HpaII alone, which provides a sensitive indicator of methylation loss, or digestion with the combination of EcoRI and HpaII, which provides a quantitative indication of loss of methylation. Bovine tissues, including adrenal cortex, all showed a much higher level of satellite methylation than cultured adrenocortical cells. After adrenocortical cells are placed in culture, some demethylation of satellite I is seen as early as 10 population doublings. By 80 population doublings, loss of satellite DNA methylation is extensive. The loss does not appear to prevent continued cell division, since an extended life span clone of bovine adrenocortical cells transfected with SV40 T antigen showed a similar pattern of extensive demethylation. Satellite demethylation has been reported in aging in vivo and the present cell culture system may provide an in vitro model for this form of genetic instability.
Adrenal Cortex↗
Intra-hepatic-arterial infusion of misonidazole--an experimental study of regional radiosensitisation by intraarterial embolisation.
The purpose of this study was to generate a selective radiosensitising effect by the intra-hepatic-arterial infusion of misonidazole (MISO). MISO (10 mg) was infused after transcatheter hepatic-arterial embolisation into the livers of rabbits bearing VX2 liver cancer. This procedure was followed by 15 Gy electron irradiation. Evaluation of tumour volume and histological examination was carried out on the 7th day after treatment. The greatest tumour response was obtained in the group which received MISO followed by radiation and was characterised by extensive fibrosis around the tumour and nearly complete tumour necrosis. Liver cell regeneration was also noted in adjacent liver tissue. The advantages of regional infusion of MISO following hepatic-arterial embolisation are: (1) Selectivity increased radiosensitivity of liver cancer alongside very low drug concentration in the plasma. (2) Reduced or absent deleterious side effects of MISO with higher tumour/normal tissue ratios of drug concentration. (3) Reduced cost due to the lower dosage of MISO required for regional infusion.
Animals↗
Actions of chiriquitoxin on frog skeletal muscle fibers and implications for the tetrodotoxin/saxitoxin receptor.
Chiriquitoxin (CqTX) from the Costa Rican frog Atelopus chiriquensis differs from tetrodoxin (TTX) only in that a glycine residue replaces a methylene hydrogen of the C-11 hydroxymethyl function. On the voltage-clamped frog skeletal muscle fiber, in addition to blocking the sodium channel and unrelated to such an action, CqTX also slows the activation of the fast potassium current in approximately 40% of the muscle fiber population. At pH 7.25, CqTX is as potent as TTX in blocking the sodium channel, with an ED50 of 3.8 nM. Its ED50's at pH 6.50 and 8.25 are 6.8 and 2.3 nM, contrasted with 3.8 and 4.3 nM for TTX. These differences are attributable to changes in the chemical states in the glycine residue. The equipotency of CqTX with TTX at pH 7.25 is explainable by an intramolecular salt bridge between the amino and carboxyl groups of the glycine function, all other surface groups in TTX and CqTX being the same. From available information on these groups and those in saxitoxin (STX), the TTX/STX binding site is deduced to be in a pocket 9.5 A wide, 6 A high, and 5 A deep. The glycine residue of CqTX probably projects out of the entrance to this pocket. Such a view of the binding site could also account for the actions of STX analogues, including the C-11 sulfated gonyautoxins and the 21-sulfocarbamoyl analogues. In the gonyautoxins the sulfate groups are equivalently placed as the glycine in CqTX, whereas in the sulfocarbamoyl toxins the sulfate groups extend the carbamoyl side-chain, leading to steric hinderance to productive binding.
Amphibian Proteins↗
Demethylation of specific sites in the 5'-flanking region of the CYP17 genes when bovine adrenocortical cells are placed in culture.
DNA methylation of CYP17 (steroid 17 alpha-hydroxylase) was studied in bovine adrenocortical cells, which lose the capacity to express this tissue-specific gene in culture by phenotypic switching. Restriction enzyme digestions, and sequencing of a lambda clone of a second CYP17 gene (CYP17A2), showed that there are at least three CYP17 genes in the bovine genome. Southern blotting of DNA digested with Msp I or Hpa II together with Eco RI was used to investigate the methylation status of Hpa II sites at -1.0 kb (H1), -1.8 kb (H2), and -2.3 kb (H4) in CYP17A1 and CYP17A2 and at -0.7 kb (H0) in CYP17A3. In cells and tissues other than white blood cells, H0 was nonmethylated whereas H1 was always methylated; H2 and H4 showed variation in methylation status among different cells and tissues. In particular, whereas H4 was methylated in the bovine adrenal cortex in vivo, there was a rapid and complete demethylation at H4 when adrenocortical cells were placed in culture. Sites downstream from H4 did not change methylation over the first six passages in culture; additionally, the coding region of CYP17 remained fully methylated under all conditions. In contrast to adrenocortical cells, DNA from fibroblasts was nonmethylated at H2, whereas all downstream sites were fully methylated. Digestion with another methylation-sensitive enzyme, Bsa HI, which has a site between H2 and H4, showed that this region is methylated in intact adrenal cortex but nonmethylated both in cultured adrenocortical cells and in fibroblasts. The specific changes in methylation at this site and at H4 in adrenocortical cells indicate a reproducible, environmentally determined change in methylation in adrenocortical cells when they are placed in culture.
Adrenal Cortex↗
Human T lymphotropic virus types I- and II-specific antibody-dependent cellular cytotoxicity: strain specificity and epitope mapping.
Antibody-dependent cellular cytotoxicity (ADCC) against human T lymphotropic virus (HTLV) types I and II was investigated using sera obtained from infected individuals or from rabbits immunized with HTLV-I or -II envelope peptides. Target cells included an HTLV-I-transformed cell line (C91/PL), an HTLV-II-transformed cell line (729pH6neo), and Epstein Barr virus (EBV)-transformed B lymphocytes expressing HTLV-I or -II env or gag gene products after infection with vaccinia/HTLV recombinants. ADCC activity was directed at HTLV-I and -II envelope glycoproteins but not against core (gag) components. In contrast to the human immunodeficiency virus system, significant cross-reactivity between HTLV-I- and -II-directed ADCC activity was observed. Epitope mapping studies using sera from rabbits that had been immunized with HTLV-I or -II envelope peptides suggested that the critical epitopes for ADCC activity are located primarily in hydrophilic regions of the exterior (gp46) part of the envelope glycoprotein.
Animals↗
Evidence for B-lymphocyte mitogen activity in Borrelia burgdorferi-infected mice.
Borrelia burgdorferi produces a mitogen for murine B lymphocytes which can be measured in vitro by polyclonal stimulation of proliferation and immunoglobulin production (R. Schoenfeld, B. Araneo, Y. Ma, L. Yang, and J. J. Weis, Infect. Immun. 60:455-464, 1992). Sonicated B. burgdorferi cells also stimulated IL-6 production by splenocyte cultures. We have used the murine model for Lyme disease described by Barthold et al. (S. W. Barthold, D. S. Beck, G. M. Hansen, G. A. Terwilliger, and K. D. Moody, J. Infect. Dis. 162:133-138, 1990) to determine whether the B. burgdorferi B-cell mitogen is expressed during active infection. To correlate arthritic changes with immune events, we have studied two strains of mice injected with B. burgdorferi; one of them, C3H/HeJ, developed severe disease, and the other, BALB/c, developed only mild disease. C3H/HeJ mice displayed a persistent 10-fold increase in circulating immunoglobulin G (IgG) levels, a 2-fold increase in IgM levels, and a 15-fold increase in peripheral lymph node B-cell numbers, providing evidence of mitogenic activity. Infected BALB/c mice also had evidence for mitogen activity, since the IgG level in serum increased three- to fourfold. The bulk of the increase in circulating IgG levels was not directed against B. burgdorferi antigens, supporting the occurrence of polyclonal B-cell activation. Analysis of IgG isotypes pointed out a contrast between C3H/HeJ and BALB/c mice in that levels of all isotypes were elevated somewhat in both strains of infected mice but IgG2a levels were much more dramatically increased in the C3H/HeJ mice (28-fold) than in the BALB/c mice (4-fold). In this study, interleukin-6 levels were found to be persistently elevated in the serum of infected C3H/HeJ mice. Interestingly, interleukin-6 levels in serum were much lower in the infected BALB/c mice. These findings indicate that the B. burgdorferi mitogen is active in infected animals and may contribute to the inflammatory and immune response to infection.
Animals↗
GABAergic circuits sharpen tuning curves and modify response properties in the mustache bat inferior colliculus.
1. The influence of bicuculline on the tuning curves of 65 neurons in the inferior colliculus of the mustache bat was investigated. Single units were recorded with multibarrel electrodes where one barrel contained bicuculline, an antagonist specific for gamma-amino-butyric acid (GABA)A receptors. Fifty-nine tuning curves were recorded from units that were sharply tuned to 60 kHz, the dominant frequency of the bat's orientation call, but six tuning curves were also recorded from units tuned to lower frequencies and whose tuning curves were broader than the 60 kHz cells. Tuning curves were constructed from peristimulus time (PST) histograms obtained over a wide range of frequency-intensity combinations. Thus tuning curves, PST histograms evoked by frequencies within the tuning curve, and rate-level functions at the best frequency were obtained before iontophoresis of bicuculline and compared with the tuning curves and response properties obtained during the administration of bicuculline. 2. Three general types of tuning curves were obtained: 1) open tuning curves that broadened on both the high- and low-frequency sides with increasing sound level; 2) level-tolerant tuning curves in which the width of the tuning curve remained uniformly narrow with increasing sound level; and 3) upper-threshold tuning curves, which did not discharge to high-intensity tone bursts at the best frequency, thereby creating closed or folded tuning curves. 3. One major finding is that GABAergic inhibition plays an important role in sharpening frequency tuning properties of many neurons in the mustache bat inferior colliculus. In response to blocking GABAergic inputs with bicuculline, the tuning curves broadened in 42% of the neurons that were sharply tuned to 60 kHz. The degree of change in most units varied with sound level: tuning curves were least affected, or not affected at all, within 10 dB of threshold and showed progressively greater changes at higher sound levels. These effects were seen in units that had open, level-tolerant, and upper-threshold tuning curves. 4. A second key result is that bicuculline affected rate-level functions and/or temporal discharge patterns in many units. Bicuculline transformed the rate-level functions of 13 cells that originally had nonmonotonic rate level functions, from strongly nonmonotonic into weakly nonmonotonic or monotonic functions. It also changed the temporal discharge patterns in 22 cells, and the changes were often frequency specific.(ABSTRACT TRUNCATED AT 400 WORDS)
Acoustic Stimulation↗
Development of collagen fibers and vasculature of the fetal TMJ.
Using 12 human fetuses, histological development and changes in connective fiber structure and fine vascular patterns have been investigated in various fetal gestational stages by light and scanning electron microscopy. The main arterial supply of the articular disc was from the bilaminar region and pterygoideus lateralis muscle. The vascular network on the disc surface was related with fluid secretion. When the bilaminar region was compressed, it caused ischemia and fibrosis as the main pathological changes in TMJ derangement. A decrease in fluid from blood vessels might occur in TMJ degeneration. Collagen fibers in the disc passed mainly anteroposteriorly. In the anterior and posterior bands, muscular tendon fibers came from the pterygoideus lateralis muscle and superior stratum of the bilaminar region. In the posterior band three-dimensional structures of collagen fibers suitable for load bearing were observed. The compass network and process on the disc showed the normal structure that is formed gradually and has functions including dispersion, pressure bearing, friction-proofing and storage of the synovial fluid. Attachments of the disc were suitable for disc function. Large elastic fibers in the posterolateral part of the superior stratum of the bilaminar region may be antagonistic to the upper head of the pterygoideus lateralis muscle fibers passing medioanteriorly, indicating that this antagonism is available for disc function.
Collagen↗
Analogs of cyclosporin A modified at the D-Ala8 position.
The conversion of [2-deutero-3-fluoro-D-Ala8]cyclosporin A (1) to a dehydroalanine analog [delta-Ala8]cyclosporin A (2) was achieved with lithium diisopropylamide in THF at low temperature. This dehydro compound is a useful intermediate for the preparation of position 8 analogs of cyclosporin A formed from it by the conjugate addition of thiol compounds. NMR conformational studies have provided evidence for the restoration of D-stereochemistry in the modified Ala8 residues. The preparation of several of these cyclosporin analogs and their bioactivities are described.
Animals↗
[Surgical treatment of esophageal cancer in post-subtotal gastrectomy patients].
Among the 1285 cases of esophageal cancer operated in our hospital during the interval 1985-1990, 11 had had subtotal gastrectomy earlier, with an incidence of 0.86%. Among these 11 cases, two had upper thoracic segment lesions which were resected and reconstructed by transverse and descending colon transplantation into the neck. Right postero-lateral thoracotomy, upper abdominal and left neck incisions were used. Nine patients had esophageal cancer in the middle and lower thoracic segment and 7 of them were operated by transplanting the remaining stomach with spleen and caudal portion of pancreas into the left thorax and esophago-gastrectomy with the remaining stomach. Exploratory thoracotomy only was done in the other 2 patients. No complication occurred. Billroth type II gastrectomy was found to be easier than Billroth type I to move the remaining stomach together with the spleen and pancreas up into the thorax and to anastomose supra-aortically. There was no direct cause-effect evidence between gastrectomy and the site of esophageal cancer. The purpose for gastrectomy (ulcer or cancer) and the type of gastrectomy (Billroth type I or II) were irrelevant to the subsequent development of esophageal cancer.
Aged↗
[Pathologic-ultrasonographic comparative study of carcinomatous lesions of experimental hepatic carcinoma in rats].
3'-Me-DAB was used to induce hepatic carcinoma in male Wistar rats. The pathologic-ultrasonographic comparative observation of forty-three carcinoma nodes of twenty-five rats showed that the echoic patterns of the nodes were determined not by the diameter, but by the pathologic types, the extent of hemorrhage or necrosis of lesions and the proliferative degree of the lattice fibers. The irregular vascularization, the dilatation of vessels and the tumoral cell fatty degeneration are related to the echoic patterns as well. This article also reports a preliminary study of the possibility that different structures and compositions of the carcinomatous nodes will produce different echoic levels.
Animals↗
[Neuropsychological and behavioral status of children with congenital heart diseases].
39 children patients with acyanoid ventricular septal defect or atrial septal defect who received cardiac operation, were compared with a age and sex matched normal control group on a battery of neuro-psychological tests, intelligence tests and children behavioral checklist. Subject were examined prior to cardiac operation and 6 months after the operation. 12 of 39 children received postoperation tests. Among them, 8 were in younger children group (5 to 8 years old), 4 were in elder children group (9 to 14 years old). Results are: 1. Neuropsychological development status: (1) Full IQ(FIQ), Verbal IQ(VIQ), and Performance IQ(PIQ) of the group with heart diseases were lower than those of normal controls, and there were significant differences. (2) In cardiac patients significant impairments were found on some scores of the Halstead-Reitan Battery in comparison with the normal control group. These findings imply that patients before cardiac operation had generalized impairments in neuropsychological function. (3) Significantly more behavioral problems especially the so called externalizing and internalizing behavioral problems, were found in cardiac patients than the controls. 2. Comparison of the pre and post operative scores were made: Both groups (cardiac patients and controls) showed significant improvements in VIQ, PIQ, FIQ and most of H-R subtests scores 6 months later. But the improvements following surgery were attributed to practice effects.
Adolescent↗