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Biomedical subjects

L Wu

Publications and source records attributed to L Wu.

At least 721 records · Page 40Linked to original sources
PubMed1991

Selenium tolerance, salt tolerance, and selenium accumulation in tall fescue lines.

High levels of soil salinity and Se concentration are coexisting problems in the San Joaquin Valley, California. Tall fescue is a potentially useful crop plant for land management in soils containing elevated concentrations of Se and salinity. Information regarding its physiological mechanism and genetic variation of Se accumulation in this species is scant. Thirteen tall fescue (Festuca arundinacea Schreb.) lines were examined for Se and salt tolerances and Se accumulation in nutrient solution culture. Genetic variation of both Se and salt tolerances was detected among six American cultivars and seven worldwide tall fescue lines. Selenium tolerance and salt tolerance are independent of each other and are negatively correlated with tissue Se and salt concentrations. These relationships suggest that an exclusion mechanism is responsible for the tolerance. This diversity of Se and salt tolerance and Se accumulation among the tall fescue lines is important for the application of this species for land management.

Genotype↗
PubMed1991

Species richness and selenium accumulation of plants in soils with elevated concentration of selenium and salinity.

Field studies were conducted in soils with elevated concentrations of Se and salinity at Kesterson, California. Biomass distribution, species richness, and selenium accumulation of plants were examined for two sites where 15 cm of surface soil was removed and replaced with fill dirt in the fall of 1989, and two sites were native soil cover. The Se concentrations in the top 15 cm of fill dirt ranged from undetectable to 36 ng g-1. For the native soil sites, Se levels ranged from 75 to 550 ng g-1. Soil Se concentrations below 15 cm ranged from 300 to 700 ng g-1 and were comparable between the fill dirt and the native soil sites. At least 20 different plant species were brought into the two fill dirt sites with the top soil. Avena fatua L., Bassia hyssopifolia Kuntze Rev. Gen. Pl., Centaurea solstitialis L., Erysimum officianale L., Franseria acanthicarpa Cav. Icon., and Melilotus indica (L.) All. contributed over 60% of the total biomass. Only 5 species were found in the native soil sites, and salt grass (Distichlis spicata L.) was the predominant species and accounted for over 80% of the total biomass. Between 1989 and 1990, two years after the surface soil replacement, the two fill dirt sites had a 70% reduction in species richness. Plant tissue selenium concentrations were found to be quite variable between plant species and between sites of sampling. At the fill dirt sites, the plant species with deep root systems accumulated greater amounts of selenium than the shallow-rooted species. The soil selenium concentration of the field soil had no negative effect on pollen fertility, seed set, and seed germination for the plant species examined. However, seedling growth was impaired by the soil selenium concentrations. This suggests that a selection pressure of soil Se concentration may have been imposed on plant species such as M. indica in an early stage of its life cycle.

Plant Development↗
PubMed1991

Selenium accumulation and selenium tolerance of salt grass from soils with elevated concentrations of Se and salinity.

Biomass production, selenium accumulation, and the role of the bioextraction of selenium by salt grass (Distichlis spicata L.) in soils with elevated concentrations of Se and salinity at Kesterson, California, were studied. Salt grass contributed more than 80% vegetative coverage and 90% dry weight in the grassland communities where the soil Se concentrations were 100 times (1000 to 3000 micrograms kg-1) higher than the Se concentrations found in soils of the control sites. No evidence for evolution of Se tolerance was found in the salt grass populations. The successful colonization of salt grass in the soil with elevated Se and salinity is attributable to the presence of high concentrations of soil sulfate. Salt grass accumulated less Se than other salt-tolerant plant species existing in the same area, and no predation of animals and insects on salt grass has been noticed. Salt grass can transpire substantial amounts of volatile Se through its plant tissue. Under field conditions, a 1-m2 salt grass plot may produce 180 micrograms volatile selenium per day. However, no reduction of soil Se concentration in the salt grass habitat was detected over a period of 1 year. A long-term monitoring of Se status is needed in order to make predictions of the effectiveness of efforts to clean up Se-contaminated soils through the use of native plant species.

Chlorides↗
PubMed1991

Effect of intravitreal dexamethasone on ocular histopathology in a rabbit model of endophthalmitis.

The histologic and clinical effect of intravitreal dexamethasone was studied in a rabbit model of experimentally induced gentamicin sensitive Staphylococcal epidermidis endophthalmitis. The study compared four treatment groups: vitrectomy alone (group I), vitrectomy plus intravitreal gentamicin (group II), vitrectomy plus intravitreal gentamicin and dexamethasone (group III), and intravitreal gentamicin and dexamethasone without vitrectomy (group IV). All eyes treated with dexamethasone, with or without vitrectomy, exhibited less clinical and histologic manifestations of inflammation. This study suggests that suppression of inflammation through the use of intravitreal dexamethasone leads to preservation of ocular architecture with potentially improved retinal function and visual benefit.

Animals↗
PubMed1991

The frequency and significance of ECG changes after transurethral prostate resection.

Although many clinicians routinely recommend a base-line preoperative electrocardiogram (ECG) and obtain frequent postoperative ECGs to screen for myocardial infarction or ischemia, the diagnostic utility of screening perioperative ECGs is unknown. The present analysis evaluates the sensitivity and specificity of the perioperative ECG and examines its value as a predictor of early postoperative cardiac events and outcomes during the postoperative year. ECGs obtained preoperatively and on the first 3 postoperative days in 206 men undergoing transurethral prostate resection were analyzed using the Minnesota Code. The occurrence of cardiac events during the operative stay was assessed by measurement of the cardiospecific MB creatine kinase isoenzyme on the first 3 postoperative days and review of the entire clinical course. Twenty-one percent of patients developed postoperative ECG changes, mostly involving the T wave; none had cardiac symptoms or sustained creatine kinase MB elevation. Changes were not significantly more common in men known to have coronary disease. The single patient who had a perioperative myocardial infarction confirmed by enzymes had no codable ECG changes. The specificity of any ECG change for perioperative infarction was 78%; of ST segment changes only, 95%. Only one of the patients (2%) who had postoperative ECG changes had a cardiac event in the year after surgery. Routine perioperative ECGs is of little diagnostic/predictive utility in situations in which the incidence of perioperative myocardial infarction is low.

Aged↗
PubMed1991

Cloning and characterization of a glutamine transport operon of Bacillus stearothermophilus NUB36: effect of temperature on regulation of transcription.

We cloned and sequenced a fragment of the Bacillus stearothermophilus NUB36 chromosome that contains two open reading frames (ORFs) whose products were detected only in cells of cultures grown in complex medium at high temperature. The nucleotide sequence of the two ORFs exhibited significant identity to the sequence of the glnQ and glnH loci of the glutamine transport system in enteric bacteria. In addition, growth response to glutamine, sensitivity to the toxic glutamine analog gamma-L-glutamylhydrazide, and glutamine transport assays with parental strain NUB3621 and mutant strain NUB36500, in which the ORF1 coding segment in the chromosome was interrupted with the cat gene, demonstrated that glnQ and glnH encode proteins that are active in the glutamine transport system in B. stearothermophilus. The inferred promoter for the glnQH operon exhibited a low homology to the -35 and -10 regions of the consensus promoter sequences of Bacillus subtilis and Escherichia coli genes. In addition, the inferred promoter for the glnQH operon also exhibited a low homology with the consensus promoter sequence deduced from the sequences of the promoters of nine different genes from B. stearothermophilus. Transcription of the glnQH operon was activated in a nitrogen-rich medium at high temperature and inhibited under the same conditions at low temperature. Transcription of the glnQH operon was partially activated in a nitrogen-poor medium at low temperature. The region upstream from glnQ contains sequences that have a low homology with the nitrogen regulator I-binding sequences and the nitrogen-regulated promoters of enteric bacteria. The effect of temperature on the regulation of the glnQH operon is discussed.

Amino Acid Sequence↗
PubMed1991

Temperature-induced protein synthesis in Bacillus stearothermophilus NUB36.

Cultures of Bacillus stearothermophilus subjected to a temperature shift-up or shift-down of 15 degrees C within the normal temperature range of growth (45 to 65 degrees C) enter a transient adaptation period before exponential growth at the new temperature. The de novo synthesis of some proteins coincides with the adaptation period.

Bacterial Proteins↗
PubMed1991

[Effects of microinjection of tutin into nucleus tractus solitarius region on the morphology of neural tissue of this area in rabbit].

Four hours after unilateral microinjection of tutin (10 micrograms) into the NTS region, the nervous tissue surrounding the center of microinjection showed the following morphologic changes: 1. Under the light microscopic examination (n = 5), the neuronal body showed chromatolysis and the nuclear basophilia enhanced in about 17% of the neurons, the lacunae of neuropil distended and gave a "spongy" appearance. The neurons with lesion mingled with the normal ones in the absence of distinct demarcation. 2. Under the electron microscopic examination (n = 3), the cisterns of rough endoplasmic reticulum distended, and the nuclear electron density increased on account of the increased nuclear chromatin in the affected cells. The organelles of dendrites decreased or disappeared; the neuroglia looked edematous. There were only a few axons which looked edematous in the neuropil. Microinjection of the same volume (1 microliter) of NS into the other side of NTS region in the same rabbit didn't show any sign of damage as those described above. Thus, our preliminary results suggest that tutin might damage the soma and dendrites of some neurons, and therefore, it might be a neuroexcitotoxin.

Animals↗
PubMed1991

Visual rehabilitation in low vision patients with age-related macular degeneration.

Using optical visual aids, visual rehabilitation was performed in 14 low vision patients (25 eyes) with age-related macular degeneration. With distance aids, visual acuity improvement appeared in 24 eyes (95%) out of the 25 eyes. Twelve eyes (48%) obtained a visual acuity equal to or better than 0.4. With near visual aids, near acuity of all eyes (100%) was improved. Thirteen eyes (52%) got the near vision equal to or better than 0.5. Ten patients could read No. 5 Chinese Reading Card. The reading success rate was 71.4%. The results suggest that application of visual aids is an effective method to improve the distant and near visual acuity of low vision patients with AMD.

Aged↗
PubMed1991

[Chemiluminescent immunoassay for insulin].

In this paper is reported solid phase chemiluminescent immunoassay for insulin with N-(4-aminobutyl)-N-ethylisoluminol (ABE1) labelled antibody and a double antibodies sandwich procedure. ABEI-CoCl2-H2O2 was used as the chemiluminescent system and the linear range of insulin was 0.3-150 microU/tube. The correlation coefficient of the log-log regression equation was 0.985 and the absolute limit of detection 0.32 microU/tube.

Humans↗
PubMed1991

[Apolipoproteins AI, B100, CII, CIII and E in human cerebrospinal fluid].

Apolipoproteins AI, B100, CII, CIII and E contents were measured by radial immunodiffusion assay kits developed by our Research Unit. The apolipoprotein in 10 human cerebrospinal fluid samples was determined. Results show that there are no apo B100, CII or trace apo CIII in human cerebrospinal fluid, the levels of apo AI in cerebrospinal fluid are 1.00 +/- 0.54 mg/dl with a range of 0.35-2.00 mg/dl and the apo E content is 0.69 +/- 0.16 mg/dl with a range of 0.51-0.99 mg/dl. The results are discussed.

Apolipoprotein A-I↗
PubMed1991

The changes of fluorescein angiography and visual electrophysiology in ocular posterior aging degeneration syndrome (OPADS).

Ocular posterior aging degeneration syndrome (OPADS) is related to age excepting inflammation, trauma, tumor, congenital abnormalities. Clinically, it can be divided into several types: degeneration, pre-retinal membrane, hole and mixed types. Changes can be seen in the choroidoretina with fluorescein angiography. In the degeneration type, there are changes of chroid-blood vessels, pigment epithelium and neovasculization. The manifestation in pre-retinal membrane type are small vascular tortuosity, expansion or fluorescein leadage, retinal pigment epithelium window defects. The hole type shows lack of retinal capillaries and retinal pigment epithelium window defects. Visual electrophysiological tests by various intensities and colors show the abnormal ERG. The bio-electricity active changes indicated the correlation among several ocular posterior aging degeneration types.

Aged↗
PubMed1991

The ocular abnormalities of blue diaper syndrome.

We describe the ocular abnormalities seen in a new metabolic disease which is deficient in the transport of tryptophan. Besides the symptoms and signs reported previously, we have found microconea, hypoplasia of the optic disc and abnormal eye movements in our case--a ten-year-old-boy. The sibling involvement and consaguineous marriage of the parents suggest a recessive heredity.

Amino Acid Metabolism, Inborn Errors↗
PubMed1991

[Anti-inflammation and toxicity of radix Aconiti coreni and rhizoma Tyhon].

Rats, mice, pigeons and rabbits were employed to study the anti-inflammatory and toxic actions of Radix Aconiti coreni and rhizoma Tyhon. The result shows that Radix Aconiti coreni and rhizoma Tyhon have similar anti-inflammatory action. rhizoma Tyhon has an obvious stimulating effect on eye conjunctiva as well as throat and stomach mucosa, while Radix Aconiti coreni does not.

Animals↗
PubMed1991

The effect of genetic determinants of low density lipoprotein levels on lipoprotein (a).

Levels of Lipoprotein(a) [Lp(a)] correlate directly with atherosclerosis risk. The Lp(a) particle is physically and chemically similar to low density lipoprotein (LDL), the main difference being the presence of apolipoprotein(a) [apo(a)] bonded to the apoB-100 moiety of LDL. Genetic variation of apo(a) primarily determines Lp(a) phenotype. However, other genetic factors may also have a role in determining Lp(a) levels. Large families provide a unique opportunity to evaluate the contribution of genetic factors to disease. In several large Utah kindreds with various genetic abnormalities of lipoprotein metabolism we determined that: 1) Lp(a) levels are associated with defects at the apoB gene; 2) Lp(a) levels are not associated with defects at the LDL-receptor gene; 3) high density lipoprotein (HDL) levels are associated with genetic variation at the apo(a) locus; and 4) the DNA sequence of the apoB-100 binding domain does not vary between siblings with high and low Lp(a) levels.

Apolipoprotein B-100↗
PubMed1991

Abnormalities of ERG in congenital aniridia.

Congenital aniridia is generally associated with nystagmus, corneal pannus, cataract, ectopia lentis, glaucoma, macular hypoplasia, optic nerve hypoplasia and compromised visual function. Many theories have been proposed, including a failure in the development of the neural ectoderm and/or an aberrant development of mesoderm. We observed the ERG from 19 patients with congenital aniridia. Fourteen patients had abnormal ERG, including the reduced a wave trough under dark adapted red stimuli with dark adaptation; abnormal a or/and b waves in dark or/and light adapted ERG or abnormal oscillatory potentials. The ERG abnormalities reflected the disturbances either in the outer retina such as photoreceptors or in the structures of inner retina. The preserved visual function and several ocular abnormalities show that the aniridia may be a consequence of several pathogenetic mechanisms. This fact supported the opinion that congenital aniridia would be a concurrent failure of both ectoderm and mesoderm in embryonate development.

Adolescent↗
PubMed1991

The significance of testing preoperative visual function in cataract using laser interferometric visual acuity and ERG.

Tests of preoperative visual function and prediction of postoperative E chart visual acuity (ECVA) using laser interferometric visual acuity (LIVA) and electroretinogram (ERG) were performed in 16 cases (19 eyes) of cataract. The results showed that the coincident rate between preoperative LIVA and postoperative ECVA was 63.2%, and there was a parallel correlation between preoperative amplitude of photopic ERG b-wave and postoperative ECVA in 79.0% of the eyes. Comparing these two methods, the test of LIVA is very simple, fast, and is easily accepted by the patients with cataract. ERG is an objective method, which is slightly influenced by dense lens, but the test is more complex. Therefore, the combined use of these two methods will provide a more comprehensive and correct evaluation of preoperative visual function and a more reliable prediction for postoperative visual acuity in patients with cataract.

Adolescent↗