Evidence of retinoid metabolism within cells of inner retina.
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Aldehyde Dehydrogenase↗
Biomedical subjects
J Huang
Publications and source records attributed to J Huang.
Role of receptor-associated 39/45 kD protein in active Heymann nephritis.
UNLABELLED: Active Heymann nephritis (HN) of rat, an autoimmune glomerular disease, is an experimental model of human membranous glomerulonephropathy (MGN), a common human glomerular disease. The putative autoantigen of HN is believed to be a large glycoprotein (gp330) present in kidneys of rat and human. Gp330 has sequence homology to low density lipoprotein receptor-related protein (LRP)/alpha 2-macroglobulin receptor and co-purifies with another 45 kD protein called receptor-associated protein (RAP) which binds to both gp330 and LRP/alpha 2-macroglobulin receptor. Since RAP co-purifies with gp330 and is thus present in the immunizing material used to induce active HN, the present study was undertaken to determine if gp330 or RAP individually could produce active HN and whether RAP had a role in the pathogenesis of active HN. Rats immunized with the traditional crude antigen (Fx1A) containing both gp330 and RAP developed typical HN. Although these rats developed low titers of autoantibody to RAP in their sera, they had no deposition of antibody to RAP in their kidneys. Rats immunized with gp330 also developed typical HN but had no autoantibody to RAP in their sera or kidneys. Rats immunized with RAP developed high titers of autoantibody to RAP in their sera but had no antibody in their kidneys and did not develop HN. Three rats were injected intravenously with polyclonal antibody to RAP and assessed seven days later for the development of passive HN. All three developed mild passive HN characterized by granular staining of polyclonal antibody along the capillary loops. CONCLUSIONS: (1) This is the first report to show that gp330 alone without the accompanying RAP can induce active HN; (2) RAP by itself does not induce active HN; (3) Autoantibodies to RAP do not appear to be involved in the pathogenesis of active HN induced with the traditional crude antigen, Fx1A; and (4) We confirm that polyclonal antibody to RAP can induce passive HN.
Animals↗
Measurement of the thermal inertia of the skin using successive thermograms taken at a stepwise change in ambient radiation temperature.
Skin thermal properties are difficult to measure in vivo in the steady state because there is a constant temperature gradient across the skin surface. However, measurement of skin thermal properties is postulated in quantitative evaluation for thermographic observation. In this study, imaging of the thermal inertia of the skin was attempted by thermographic measurements at a stepwise change in ambient radiation temperature achieved by quickly switching two hoods maintained at different temperatures. Using this technique, a total of 65 thermograms were sequentially recorded at intervals of 0.5 s beginning 2 s before the stepwise change. The image of skin thermal inertia was estimated by applying statistical curve fitting at each pixel of the thermograms. In addition, the emissivity and true temperature of the skin were also determined, together with thermal inertia, in a single measurement. Measurements were made at different sites on 10 subjects. The average values of thermal inertia of normal skin were scattered throughout a range from 1.4 x 10(3) to 2.1 x 10(3) W s1/2 m-2 K-1. Investigations of the relationship between skin blood flow and thermal inertia were also made by imaging thermal inertia when skin blood flow was changed by applying a vasodilator or vasoconstrictor on the skin surface. In a comparison with the data measured by laser Doppler flowmetry, the average slope of skin blood flow versus thermal inertia was 2.88 x 10(-4) V per W s1/2 m-2 K-1, and the thermal inertia of the skin with no blood flow was 1.03 x 10(3) W s1/2 m-2 K-1. The results also show an almost linear correlation between skin blood flow and thermal inertia in each individual, but inter-individual differences were also observed. The results suggest that skin blood flow distribution can be estimated by non-contact imaging of thermal inertia.
Humans↗
Improvement of imaging of skin thermal properties by successive thermographic measurements at a stepwise change in ambient radiation temperature.
Imaging of skin thermal properties was attempted by successive thermographic measurements of the skin surface with a stepwise change in ambient radiation temperature. In order to produce the stepwise change in ambient radiation temperature, two hoods maintained at different temperatures, 20 degrees C and 60 degrees C, were mechanically switched. A total of 65 thermograms were taken from 2 s before to 32 s seconds after the hood switching. Images of skin emissivity, emissivity-corrected skin temperature and thermal inertia were obtained by least-squares fitting at each pixel of 64 thermograms. Measurements were performed on the forehead, cheek, forearm, palm and back of the hand of 10 healthy male subjects. Differences in emissivity between sites and subjects were insignificant. Significant differences were observed in thermal inertia values between sites. Great improvements in the imaging of thermal inertia have been achieved by applying least-squares fitting to 64 thermograms instead of by computations from only two thermograms as in the previous study. Non-contact measurement and visualization of skin thermal properties are significant advantages of this method.
Adult↗
Differential role of interferon-gamma in the potentiating effect of muramyl peptides for enhanced responses to lipopolysaccharide in mice: effect of cyclosporin A.
Cyclosporin A (CsA) administration reduced mortality in mice sensitized to endotoxic toxicity by various agents, such as muramyl dipeptide (MDP) or a lipophilic derivative. CsA is an inhibitor of a variety of T cell responses, suggesting that muramyl peptides could influence LPS-induced effects via the release of lymphokine. The potentiation of TNF production by pretreatment with muramyl peptides was comparable in nude mice and in controls, indicating that it is a T-independent mechanism, and CsA produced a similar inhibition in both groups. Neutralizing antibody to IFN-gamma did not change the elevated TNF level obtained in the blood when LPS was given after a muramyl peptide. However, the same treatment with anti-IFN-gamma MAb prevented the death of mice challenged with LPS plus MDP or plus a lipophilic derivative displaying similar effects. In comparing three selected muramyl peptides, we also show that the priming effect could be dissociated from the toxic synergism with LPS.
Acetylmuramyl-Alanyl-Isoglutamine↗
Aggressive pattern of angina after successful coronary angioplasty: the role of clinical and angiographic factors.
To assess possible clinical and angiographic factors associated with acute coronary events following PTCA, we performed quantitative angiography in 168 consecutive patients who had undergone successful angioplasty in a native vessel (94 for stable angina, 74 for unstable angina), and who were restudied (24 +/- 15 weeks; range 4 to 52) because of recurrent anginal symptoms. Of the 168 patients, 38 (Group 1) were restudied because the pattern of angina was aggressive (unstable angina in 31, myocardial infarction in 7) and 130 because of effort-related angina (Group 2). the two patient groups were well matched for extent of initial disease but patients in Group 1 were younger (P=0.03). PTCA for unstable angina was originally performed more frequently in Group 1 than in Group 2 (27 of 38 patients (71% vs 47 of 130 patients (36%), P=0.0004). Disease progression in non-dilated segments occurred in 10 patients (26%) in Group 1 compared with eight (6%) in Group 2 (P=0.0004). Disease progression in non-dilated segments occurred in nine patients (24%) in Group 1 and in Group 2 (P=0.0004). Disease progression in non-dilated segments occurred in nine patients (24%) in Group 1 and in 10 (8%) in Group 2 (P=0.0006). Our conclusion is that patients who require re-investigation as a result of angina which has become aggressive following PTCA are usually those who originally underwent PTCA for unstable angina. These patients have a higher incidence of occlusive restenosis or disease progression.
Adult↗
Detection of CYP2C9 polymorphism based on the polymerase chain reaction in Chinese.
Cytochrome P450 (CYP) 2C9 catalyses the metabolism of a wide range of drugs. Previous studies have shown the differences in the amino acid composition among CYP2C9 variants at Cys144/Arg, Tyr358/Cys, Leu359/Ile, and Gly417/Asp. PCR-endonuclease digestion methods have been developed to detect these four possible polymorphisms. The T416-->C mutation in exon 3 of CYP2C9 (Cys144-->Arg) creates an Ava II site. In the 135 subjects we tested, all leukocyte DNA samples showed a complete Ava II digestion indicating homozygous C416 (Arg144). A Tyr358-->Cys mutation will create a Nsi I site at codon 1057-1063 in exon 7. In 40 subjects tested, all samples showed negative results. DNA sequencing on a few samples showed Tyr358Ile359. A mismatched PCR primer pair was then designed to detect codon C1061-->A (Leu359-->Ile) mutation. In 115 subjects tested, 111 samples showed a complete Nsi I digestion (Ile359) and four samples showed heterozygous results. Another mismatched PCR primer pair was used to confirm the C1061 codon in heterozygous subjects. The four heterozygous subjects showed partial digestion with endonuclease Kpn I, which confirmed the heterozygous Ile/Leu at amino acid 359. The G1236-->A mutation in exon 8 of CYP2C9 (Gly417-->Asp) creates a Hph I site. In all 46 subjects, homozygous G1236 (Gly417) was found. Most Chinese subjects actually have Arg144 Tyr358 Ile359 Gly417 in CYP2C9 as previously reported human-2. Furthermore, we found an A-->T (+12 position in intron 2) mutation in our CYP2C9 sequencing process. The mutation creates a NIa III site.(ABSTRACT TRUNCATED AT 250 WORDS)
Alleles↗
Characterization of the cell-wall polysaccharides of Arabidopsis thaliana leaves.
The cell-wall polysaccharides of Arabidopsis thaliana leaves have been isolated, purified, and characterized. The primary cell walls of all higher plants that have been studied contain cellulose, the three pectic polysaccharides homogalacturonan, rhamnogalacturonan I and rhamnogalacturonan II, the two hemicelluloses xyloglucan and glucuronoarabinoxylan, and structural glycoproteins. The cell walls of Arabidopsis leaves contain each of these components and no others that we could detect, and these cell walls are remarkable in that they are particularly rich in phosphate buffer-soluble polysaccharides (34% of the wall). The pectic polysaccharides of the purified cell walls consist of rhamnogalacturonan I (11%), rhamnogalacturonon II (8%), and homogalacturonan (23%). Xyloglucan (XG) accounts for 20% of the wall, and the oligosaccharide fragments generated from XG by endoglucanase consist of the typical subunits of other higher plant XGs. Glucuronoarabinoxylan (4%), cellulose (14%) and protein (14%) account for the remainder of the wall. Except for the phosphate buffer-soluble pectic polysaccharides, the polysaccharides of Arabidopsis leaf cell walls occur in proportions similar to those of other plants. The structure of the Arabidopsis cell-wall polysaccharides are typical of those of many other plants.
Amino Acids↗
Molecular characterization of the eps gene cluster of Pseudomonas solanacearum and its transcriptional regulation at a single promoter.
Production of EPS I, an unusual exopolysaccharide virulence factor of the phytopathogen Pseudomonas solanacearum, requires the 18 kb eps gene cluster. DNA sequence analysis of the first seven genes of eps (epsAPBCDEF), subcellular localization of their products in maxicells, and phoA fusion analysis showed that: (i) epsA, epsB, epsE, and epsF encode exported or membrane-associated proteins probably involved in polymerization and/or export of EPS I; (ii) epsC and epsD encode soluble enzymes probably involved in synthesis of sugar components of EPS I (N-acetylgalactosaminuronic acid and possibly N-acetyltrideoxygalactose, respectively); and (iii) epsP probably encodes a phosphatase involved in EPS I production in an unknown way. Non-polar insertional mutagenesis showed that most, if not all, of these eps genes are absolutely required for production of EPS I. Using random eps::lacZ fusions and primer extension we located a transcription start site and promoter upstream of epsA. Analysis of a plasmid with this promoter fused to lacZ showed that a 140 bp regulatory region upstream of the eps transcription start site was sufficient for normal regulation of eps transcription by the multicomponent virulence gene regulatory network of P. solanacearum. Deletion of this eps promoter from a plasmid-borne epsAPBCDE::lacZ fusion reduced its expression 10-fold, indicating that this promoter alone is responsible for regulated transcription of an eps operon composed of at least epsAPBCDE. Analysis of genomic and plasmid-borne eps::lacZ fusions suggested that most remaining eps genes are part of this same operon or, and this is less likely, comprise a second co-ordinately regulated eps operon.
Amino Acid Sequence↗
Regulation of lipopolysaccharide-induced tumor necrosis factor production by cyclosporin A in mice primed with muramyl dipeptide.
The effect of cyclosporin A (CsA) on tumor necrosis factor (TNF) or interleukin-6 (IL-6) production was evaluated in vivo in primed or unprimed mice challenged with lipopolysaccharide (LPS). Both pretreatment with BCG infection or with muramyl dipeptide (MDP) prior to LPS challenge resulted in an increase in the cytokine bioactivity level in the blood. CsA administration inhibited the TNF production. In unprimed mice, either normal or sensitized to LPS lethality by galactosamine treatment, a marked decrease in the cytokine level was observed after injection of CsA. After adrenalectomy, the yield of both TNF and IL-6 following LPS injection was markedly elevated but decreased by CsA administration. Ex vivo experiments have shown that the inhibitory effect of CsA could be demonstrated at the level of macrophages from mice previously given the drug. If mice had received MDP, in vitro responses of cells to LPS were enhanced but again CsA decreased the mRNA expression and protein secretion.
Acetylmuramyl-Alanyl-Isoglutamine↗
Stimulation of interleukin-8 production in epithelial cell lines by Helicobacter pylori.
Following exposure to Helicobacter pylori cells, epithelial cell lines secreted interleukin-6 (IL-6) and IL-8 but not tumor necrosis factor alpha. Purified IL-6 alone did not stimulate IL-8 production from the cell lines tested, indicating that IL-6 was not an intermediary in IL-8 induction. Enhanced IL-8 secretion occurred in a time- and dose-dependent manner. None of 12 antibiotics tested exhibited a significant effect on IL-8-inducing activity, suggesting that preformed antigens were responsible for stimulating IL-8 secretion in vitro. Live bacterial cells caused the highest level of stimulation. Proteinase-digested and heated (56 or 100 degrees C) cells had significantly reduced stimulatory activities. Purified H. pylori lipopolysaccharide, but not exopolysaccharide, stimulated low-level secretion of IL-8, but only at high concentrations, while a water-extracted H. pylori antigen preparation was strongly stimulatory for HEp-2 cells. No reduction in IL-8-stimulatory activity was observed for H. pylori mutants negative for urease activity, production of a major lipoprotein, and motility. The noncytotoxic strain CCUG 915 stimulated lower IL-8 levels than other isolates. However, the otherwise isogenic cytotoxin-negative mutant 17874 delta vacA (S. H. Phadnis, D. Ilver, L. Janzon, S. Normark, and T. U. Westblom, Infect. Immun. 62:1557-1565, 1994) had the same IL-8-stimulatory ability as the parent strain, suggesting that surface proteins other than the vacuolating cytotoxin are involved in IL-8 stimulation.
Bacterial Proteins↗
The putative neuraminyllactose-binding hemagglutinin HpaA of Helicobacter pylori CCUG 17874 is a lipoprotein.
The ability of certain strains of Helicobacter pylori to cause sialic acid-sensitive agglutination of erythrocytes has been attributed to the HpaA protein (D.G. Evans, T.K. Karjalainen, D. J. Evans, Jr., D. Y. Graham, and C.H. Lee, J. Bacteriol. 175:674-683, 1993), the gene for which has been cloned and sequenced. On the basis of the hydropathy plot of HpaA and the presence of a potential lipoprotein signal sequence and modification site, and because of the similarities of these features with those of the cell envelope lipoprotein Lpp20 of H. pylori, we examined the possibility that HpaA was also a lipoprotein. Posttranslational processing of the HpaA protein expressed by the cloned gene was sensitive to globomycin, an inhibitor of the lipoprotein-specific signal peptidase II. Antibodies raised to the putative sialic acid-binding region of HpaA failed to bind to the surface of H. pylori cells in immunoelectron microscopy but instead were observed to have labeled the cytoplasm when thin sections were examined. This antibody recognized a 29,000-M(r) protein in Western blots (immunoblots) of cell extracts of H. pylori and Escherichia coli cells expressing the cloned hpaA gene. Determination of the sequence of hpaA from strain CCUG 17874 indicated significant differences from that determined by Evans and coworkers in the above-mentioned study, including extension of the gene into the open reading frame 3 downstream of hpaA to produce a protein with an M(r) of 26,414. Localization of HpaA indicated that it was predominantly located in the cytoplasmic fraction of the cell in both E. coli and H. pylori. HpaA was not observed in the sarkosyl-insoluble outer membrane fraction. An isogenic mutant generated by insertional inactivation of hpaA was unaffected in its ability to bind four different human cell lines as well as fixed sections of gastric tissue and had hemagglutination properties identical to those of the wild type. The data collectively suggest that HpaA is a nonessential lipoprotein internal to the H. pylori cell and that it is not involved in adhesion.
Adhesins, Bacterial↗
A complex network regulates expression of eps and other virulence genes of Pseudomonas solanacearum.
We have discovered an unusual and complex regulatory network used by the phytopathogen Pseudomonas solanacearum to control transcription of eps, which encodes for production of its primary virulence factor, the exopolysaccharide EPS I. The major modules of this network were shown to be three separate signal transduction systems: PhcA, a LysR-type transcriptional regulator, an dual two-component regulatory systems, VsrA/VsrD and VsrB/VsrC. Using lacZ fusions and RNA analysis, we found that both PhcA and VsrA/VsrD control transcription of another network component, xpsR, which in turn acts in conjunction with vsrB/vsrC to increase transcription of the eps promoter by > 25-fold. Moreover, gel shift DNA binding assays showed that PhcA specifically binds to the xpsR promoter region. Thus, the unique XpsR protein interconnects the three signal transduction systems, forming a network for convergent control of EPS I in simultaneous response to multiple environmental inputs. In addition, we demonstrate that each individual signaling system of the network also acts independently to divergently regulate other unique sets of virulence factors. The purpose of this complex network may be to allow this phytopathogen to both coordinately or independently regulate diverse virulence factors in order to cope with the dynamic situations and conditions encountered during interactions with plants.
Amino Acid Sequence↗
Model for a pump that drives circulation of pleural fluid.
Physical and mathematical models were used to study a mechanism that could maintain the layer of pleural fluid that covers the surface of the lung. The pleural space was modeled as a thin layer of viscous fluid lying between a membrane carrying tension (T), representing the lung, and a rigid wall, representing the chest wall. Flow of the fluid was driven by sliding between the membrane and wall. The physical model consisted of a cylindrical balloon with strings stretched along its surface. When the balloon was inflated inside a vertical circular cylinder containing a viscous fluid, the strings formed narrow vertical channels between broad regions in which the balloon pressed against the outer cylinder. The channels simulated the pleural space in the regions of lobar margins. Oscillatory rotation of the outer cylinder maintained a lubricating layer of fluid between the balloon and the cylinder. The thickness of the fluid layer (h), measured by fluorescence videomicroscopy, was larger for larger fluid viscosity (mu), larger sliding velocity (U), and smaller pressure difference (delta P) between the layer and the channel. A mathematical model of the flow in a horizontal section was analyzed, and numerical solutions were obtained for parameter values of mu, U, delta P, and T that matched those of the physical model. The computed results agreed reasonably well with the experimental results. Scaling laws yield the prediction that h is approximately (T/delta P)(microU/T)2/3. For physiological values of the parameters, the predicted value of h is approximately 10(-3) cm, in good agreement with the observed thickness of the pleural space.
Body Fluids↗
Cognitive complexity and scanning by Chinese and American students in an American university.
75 Chinese and 75 American students' perceptual styles of cognitive complexity and scanning (focus versus nonfocus) were analyzed. The American students, 22 Chinese women, and 18 Chinese social science and humanities students scored as more complex than the 53 Chinese men and 57 Chinese natural science and engineering students. It was also observed that the Chinese men and American women scored as more focused than the 22 Chinese women and 43 American men.
Adult↗
[The effect of diethyl-dithiocarbamate on the distribution of pingyangmycin in vivo].
Diethyl-dithiocarbamate (DDC) is a compound with wide spectrum of pharmacologic activities. It has been shown to enhance the tumor cytotoxic effect of Pingyangmycin (PYM). In this paper, the effect of DDC on the distribution of 99mTc-labeled PYM in mice bearing subcutaneous transplant of Ehrlich carcinoma is reported. The results indicate that DDC did not affect the absolute concentration of PYM in the tumor but it accelerated its excretion in the urine and decreased the concentration of PYM in the non-tumorous tissues. Therefore, DDC could help alleviate the damaging effect of PYM on normal tissues without affecting its tumor cytotoxic activity.
Animals↗
An experimental study of intravascular stent in abdominal aorta of atherosclerotic miniature pigs.
To study the effects of nitinol alloy stent in the treatment of atherosclerotic arterial stenosis, eight miniature pigs were subject to abdominal aortic balloon denudation and high-fatty food. Then 8 nitinol alloy stents were implanted into each abdominal aortas of pigs. The pigs were equally divided into two groups. One group was given captopril (3 mg/kg/d). All animals were sacrified for pathological examination 6 to 10 months after stent implantation. The degree of arterial intima proliferation in the areas of stent implantation not significantly different from that of areas of balloon denudation alone; the atherosclerotic lesions were found at the arterial surface of stent implantation sites. The intima layer was rich in smooth muscle cells, with atherosclerotic plaque formed around the stent wire. On the other hand, significant decrease in arterial intima proliferation was found in group II with no atherosclerotic plaque. The arterial stenosis resulting from atherosclerotic lesion could not be prevented by implantation of intravascular stent, and on the contrary, the mechanical stress of stent wire might worsen the atherosclerosis. Captopril might impede the development of atherosclerotic stenosis after stent implantation.
Alloys↗
[A study on five-year postoperative results of radial keratotomy].
Radial keratotomy was performed on 285 myopic eyes (155 cases) with a mean of -5.48D. 1-2 pairs of flag-shaped transverse incisions were also made to correct corneal astigmatism over 1.00D. After a postoperative follow-up of 4-5 years, the mean keratometric corneal refractive power, corneal astigmatism and spherical equivalent refraction of the eyes were reduced by 3.98D, 0.36D and -4.74D, respectively. The rates of emmetropia, overcorrection and undercorrection were 70.7%, 15.5% and 13.8%, respectively. The decrease of the best corrected visual acuity by over two lines occurred in 3.4% of the eyes. The percentage of eyes with postoperative uncorrected visual acuity > or = 1.0 was 63.8% and that > or = 0.6, 89.7%. The complications included corneal microperforation in 4.6%, visual fluctuation in 34.1% and glare in 8.8% which decreased to 1.8% after postoperative 6 months. The mean rate of endothelial cell loss at the central optical zone was 6.2% in the postoperative 1-2 years.
Adolescent↗