Search PubMed⌕ Search

Biomedical subjects

L Jiang

Publications and source records attributed to L Jiang.

At least 145 records · Page 8Linked to original sources
PubMed1999

[Rapid detection of trisomy 21 by quantitative polymerase chain reaction].

OBJECTIVE: Studying gene diagnosis of trisomy 21 by means of quantitative polymerase chain reaction(PCR). METHODS: Polymorphic short tandem repeat(STR) at D21S11 served as the gene marker, and a pair of primers was synthesized. The samples from 11 normal subjects and 28 cases of trisomy 21 were analyzed by quantitative PCR. RESULTS: 10 normal subjects showed two bands with a ratio of 1:1, and a subject showed one band. Of 28 cases of trisomy 21, 24 cases showed two bands with a ratio of 2:1, 3 cases showed three bands with a ratio of 1:1:1, and 1 case showed one band. CONCLUSION: Polymorphic STR at D21S11 is a valuable gene marker for diagnosis of trisomy 21. Trisomy 21 can be diagnosed rapidly and accurately within 24 hours by quantitative PCR.

Down Syndrome↗
PubMed1999

Residential magnetic fields predicted from wiring configurations: I. Exposure model.

A physically based model for residential magnetic fields from electric transmission and distribution wiring was developed to reanalyze the Los Angeles study of childhood leukemia by London et al. For this exposure model, magnetic field measurements were fitted to a function of wire configuration attributes that was derived from a multipole expansion of the Law of Biot and Savart. The model parameters were determined by nonlinear regression techniques, using wiring data, distances, and the geometric mean of the ELF magnetic field magnitude from 24-h bedroom measurements taken at 288 homes during the epidemiologic study. The best fit to the measurement data was obtained with separate models for the two major utilities serving Los Angeles County. This model's predictions produced a correlation of 0.40 with the measured fields, an improvement on the 0.27 correlation obtained with the Wertheimer-Leeper (WL) wire code. For the leukemia risk analysis in a companion paper, the regression model predicts exposures to the 24-h geometric mean of the ELF magnetic fields in Los Angeles homes where only wiring data and distances have been obtained. Since these input parameters for the exposure model usually do not change for many years, the predicted magnetic fields will be stable over long time periods, just like the WL code. If the geometric mean is not the exposure metric associated with cancer, this regression technique could be used to estimate long-term exposures to temporal variability metrics and other characteristics of the ELF magnetic field which may be cancer risk factors.

Algorithms↗
PubMed1999

Residential magnetic fields predicted from wiring configurations: II. Relationships To childhood leukemia.

Case-control data on childhood leukemia in Los Angeles County were reanalyzed with residential magnetic fields predicted from the wiring configurations of nearby transmission and distribution lines. As described in a companion paper, the 24-h means of the magnetic field's magnitude in subjects' homes were predicted by a physically based regression model that had been fitted to 24-h measurements and wiring data. In addition, magnetic field exposures were adjusted for the most likely form of exposure assessment errors: classic errors for the 24-h measurements and Berkson errors for the predictions from wire configurations. Although the measured fields had no association with childhood leukemia (P for trend=.88), the risks were significant for predicted magnetic fields above 1.25 mG (odds ratio=2.00, 95% confidence interval=1.03-3.89), and a significant dose-response was seen (P for trend=.02). When exposures were determined by a combination of predictions and measurements that corrects for errors, the odds ratio (odd ratio=2.19, 95% confidence interval=1.12-4.31) and the trend (p =.007) showed somewhat greater significance. These findings support the hypothesis that magnetic fields from electrical lines are causally related to childhood leukemia but that this association has been inconsistent among epidemiologic studies due to different types of exposure assessment error. In these data, the leukemia risks from a child's residential magnetic field exposure appears to be better assessed by wire configurations than by 24-h area measurements. However, the predicted fields only partially account for the effect of the Wertheimer-Leeper wire code in a multivariate analysis and do not completely explain why these wire codes have been so often associated with childhood leukemia. The most plausible explanation for our findings is that the causal factor is another magnetic field exposure metric correlated to both wire code and the field's time-averaged magnitude.

Algorithms↗
PubMed1999

[Different expressions of bFGF gene in three kinds of skeletal muscles].

OBJECTIVE: To explore the distribution characteristics of bFGF gene, bFGF protein and receptor in rat skeletal muscles. METHODS: bFGF gene, and bFGF protein and receptor in rat gastrocnemius muscles were localized by ABC immunohistochemical method, in situ hybridization and a special staining methods. RESULTS: Based on the results from the special staining, the fibers in rat gastrocnemius muscle could be divided into three types: type I, II a and II b. The positive expression of bFGF gene was only found in the cytoplasm of type I and type II a fibers. The immunohistochemical localization showed that bFGF protein and its receptor were found in the connective parts of muscle endomysium in fibers of type I and type II a. CONCLUSION: This is the first study to identify the different expressions of bFGF gene, bFGF protein and its receptor in rat skeletal muscles. The results will help to understand the action and the relationship between bFGF autocrine and the embryo development of skeletal muscle fibers.

Animals↗
PubMed1999

[Clinical study on retarding aging effect of tongbu recipe to traditional Chinese medicine].

OBJECTIVE: To study the mechanism of Tongbu No. 1 (TB1, a prescription for reinforcing Kidney and Spleen, clearing up the bowel viscera to send Turbid downward and regulating Qi and blood) in retarding aging. METHODS: A controlled, multiple indexes study was conducted in 56 old subjects randomized into 3 groups. RESULTS: TB1 (containing ginseng leaf, cistanche, fleeceflower root, immature bitter orange, rhubarb, etc) could improve various symptoms of aging, and had the effect in regulating immune and endocrinal function, scavenging free radicals and adjusting coli flora. The effects of TB1 and TB2 (containing ginseng leaf, cistanche and fleeceflower root) were different significantly (P < 0.05, P < 0.01). CONCLUSION: TB1 has a good comprehensive effect in retarding aging.

Aged↗
PubMed1999

[Computer-aided 3-D reconstruction and measurement of optic canal and intracanalicular structures].

OBJECTIVE: To reconstruct the human optic canal and its inner structures, and to provide knowledge of this region in detail for optic nerve decompression and further understanding on the pathologic mechanisms of indirect optic nerve injury. METHODS: 6 optic canals and its inner structures were reconstructed by using a computer-aided 3-dimensional (3-D) reconstruction system. Quantitative measurement for the canal wall thickness, bony canal transverse area, optic nerve transverse area, dual sheath transverse area, subarachnoid space transverse area, and subarachnoid space volume were done by means of the computer morphometric analysis system. The detailed spatial relations among intracanalicular structures were also carefully identified on the 3-D models. RESULTS: The thinnest portion of the canal was the middle part of the medial wall (0.45 +/- 0.35)mm, and the narrowest space was in the middle part of the optic canal [the transverse area was (18.21 +/- 2.50) mm(2)]. The volume of subarachnoid space which can be considered the compensatory space for distention incurred by the hemorrhage, optic nerve edema, or hematoma was (21.16 +/- 4.31) mm(3). At the cranial opening, the middle part and orbital opening, its transverse area was (4.45 +/- 1.12) mm(2), (2.68 +/- 1.32) mm(2), (1.23 +/- 0.83) mm(2), respectively. CONCLUSIONS: In the middle part, the restraining of the bony canal on injured nerve may be the most powerful. Since the compensatory space was limited, even a tiny amount of blood or swelling of the nerve may cause optic compression. Because the compensatory space for distention gradually decreases from cranial end to orbital end, the middle part and the anterior part of the optic canal and dural sheath are critical in optic nerve decompression.

Humans↗
PubMed1999

[Development of air microbe sampler with micropore filter membrane].

Dual head air microbe sampler with a large flow capacity of 100 liters per minute was manufactured. The sampler possesses simple structures, light weight, convenient operation and higher sampling efficiency, equal to 77%-96% of the grade six Anderson sampler. Sampling time is a main factor affecting sampling efficiency. This device is suitable for the determination of degree of biological clean air in clean environment and the detection of the pathogenic microbes in ward and public places and also microbes in ordinary environment.

Air Microbiology↗
PubMed1999

[Effects on the amount of total hemolytic complement levels(CH50) and immunoglobulin in serum induced by the implantation of biomaterials into rats].

Three kinds of biomaterials, PES, YP and SR, were implanted into the subcutaneous tissue of rats and stayed there for 7, 14, 30, 60 and 90 days. Then using the immunity assaying system (Beckman, ICS) and the standard method of measuring the value of total hemolytic complement levels (CH50), we determined the values of immunoglobulin and CH50 in serum of rats. The results showed the amounts of IgG and IgA of rats with the implanted YP and SR materials were significantly higher than those of the control groups, and their value of CH50 was significantly lower than that of the control group. There was no significant difference between the PES group and the control group.

Animals↗
PubMed1999

[Evaluation of diagnostic value of 18 kDa antigen in alveolar echinococcosis].

AIM: To evaluate the 18 kDa antigen in diagnosis of human alveolar echinococcosis. METHODS: A total of 214 sera from patients with alveolar echinococcosis (AE, 33), cystic echinococcosis (CE, 69), cysticercosis (30) and healthy controls (82) were examined by Western blotting to detect the antibodies against 18 kDa antigen using both antigens from protoscoleces of E. granulosus (Eg) and E. multilocularis (Em). All the sera were tested simultaneously by ELISA to detect the antibodies against hydatid cystic fluid antigens of sheep as a comparison. RESULTS: The positive rate by ELISA was 93.9% in AE, 85.5% in CE, 50% in cysticercosis and 6.1% in healthy controls, respectively, suggesting a critical cross-reaction and a certain degree of nonspecific reaction. The serum positive rates by Western blotting with the 18 kDa antigen of Eg and Em were 90.9% and 90.9% in AE, 10.1% and 13% in CE, 13.3% and 16.7% in cysticercosis, respectively. No positive was found in the sera from healthy controls. CONCLUSION: The 18 kDa antigen may be used in the differential diagnosis of AE from CE.

Antigens, Helminth↗
PubMed1999

[Experimental and clinic study of the maxillary sinus plasty following Caldwell-Luc].

OBJECTIVE: To investigate the clinical effect of surgical procedures on patients with chronic maxillary sinus disease. METHOD: On the basis of experimental study with animal, this prospective study included 63 patients with chronic maxillary sinus disease who had a maxillary sinus plasty following Caldwell-Luc. The operation procedures included anterior wall ring-drilling, and middle meatal antrostomy as well as sinus wall plasty. RESULT: Experimental results showed that the repair and regeneration of maxillary sinus mucosa was intact in dogs after 5 weeks of radical operation. Clinical study indicated that the condition of anterior wall with a resutured bone-lid was normalized radiographically during the follow up time of 1-3 months. The patency rate of the middle meateal antrostomy 18-42 months post-operatively (average 28 months) is 96%. CONCLUSION: We conclude from the study that the maxillary sinus plasty recovers anatomic construction, maintains physiological drainage way and provides a good environment for repair and regeneration of the sinus mucosa.

Adolescent↗
PubMed1998

Integral membrane protein sorting to vacuoles in plant cells: evidence for two pathways.

Plant cells may contain two functionally distinct vacuolar compartments. Membranes of protein storage vacuoles (PSV) are marked by the presence of alpha-tonoplast intrinsic protein (TIP), whereas lytic vacuoles (LV) are marked by the presence of gamma-TIP. Mechanisms for sorting integral membrane proteins to the different vacuoles have not been elucidated. Here we study a chimeric integral membrane reporter protein expressed in tobacco suspension culture protoplasts whose traffic was assessed biochemically by following acquisition of complex Asn-linked glycan modifications and proteolytic processing, and whose intracellular localization was determined with confocal immunofluorescence. We show that the transmembrane domain of the plant vacuolar sorting receptor BP-80 directs the reporter protein via the Golgi to the LV prevacuolar compartment, and attaching the cytoplasmic tail (CT) of gamma-TIP did not alter this traffic. In contrast, the alpha-TIP CT prevented traffic of the reporter protein through the Golgi and caused it to be localized in organelles separate from ER and from Golgi and LV prevacuolar compartment markers. These organelles had a buoyant density consistent with vacuoles, and alpha-TIP protein colocalized in them with the alpha-TIP CT reporter protein when the two were expressed together in protoplasts. These results are consistent with two separate pathways to vacuoles for membrane proteins: a direct ER to PSV pathway, and a separate pathway via the Golgi to the LV.

Amino Acid Sequence↗
PubMed1998

cDNA cloning and functional characterization of the mouse Ca2+-gated K+ channel, mIK1. Roles in regulatory volume decrease and erythroid differentiation.

We have cloned from murine erythroleukemia (MEL) cells, thymus, and stomach the cDNA encoding the Ca2+-gated K+ (KCa) channel, mIK1, the mouse homolog of hIK1 (Ishii, T. M., Silvia, C., Hirschberg, B., Bond, C. T., Adelman, J. P., and Maylie, J. (1997) Proc. Natl. Acad. Sci.(U. S. A. 94, 11651-11656). mIK1 mRNA was detected at varied levels in many tissue types. mIK1 KCa channel activity expressed in Xenopus oocytes closely resembled the Kca of red cells (Gardos channel) and MEL cells in its single channel conductance, lack of voltage-sensitivity of activation, inward rectification, and Ca2+ concentration dependence. mIK1 also resembled the erythroid channel in its pharmacological properties, mediating whole cell and unitary currents sensitive to low nM concentrations of both clotrimazole (CLT) and its des-imidazolyl metabolite, 2-chlorophenyl-bisphenyl-methanol, and to low nM concentrations of iodocharybdotoxin. Whereas control oocytes subjected to hypotonic swelling remained swollen, mIK1 expression conferred on oocytes a novel, Ca2+-dependent, CLT-sensitive regulatory volume decrease response. Hypotonic swelling of voltage-clamped mIK1-expressing oocytes increased outward currents that were Ca2+-dependent, CLT-sensitive, and reversed near the K+ equilibrium potential. mIK1 mRNA levels in ES cells increased steadily during erythroid differentiation in culture, in contrast to other KCa mRNAs examined. Low nanomolar concentrations of CLT inhibited proliferation and erythroid differentiation of peripheral blood stem cells in liquid culture.

Animals↗
PubMed1998

A new step to the mechanism of the enhancement effect of gold nanoparticles on glucose oxidase.

Quantum size effect was strongly supported by the experiment on correlation between size of gold nanoparticles (below 10 nm) and activity of glucose oxidase attached to them. The attractive enhancement effect of gold nanoparticles on the activity of glucose oxidase was then satisfactorily explained. In this experiment, 2 nm and 6 nm (average diameter) particles were obtained on monolayer matrix. The 2 nm particles proved to be much more able to increase the activity of glucose oxidase.

Adsorption↗
PubMed1998

Solution conformation of an ET(B) selective agonist, ET-1[Cys(Acm)1,15,Ala3,Leu7,Aib11], in CD3OH/H2O by 1H NMR and molecular modelling.

To understand the basic structural requirements for the biological activity of endothelin peptides, the solution structure of an ETB selective agonist, ET-1[Cys-(Acm)1,15, Ala3,Leu7,Aib11, was investigated by 1H NMR spectroscopy and molecular modelling. The structure is characterised by an alpha-helical conformation between residues Ser5-His16 but is undefined at both the N and C termini. To date, neither the solution structures of linear modified peptides nor the effects of a methanol/water solvent system have been examined for endothelin or endothelin-like peptides. This structure plays an important role towards the design of endothelin receptor selective agonists and antagonists.

Amino Acid Sequence↗
PubMed1998

Autosomal dominant distal renal tubular acidosis is associated in three families with heterozygosity for the R589H mutation in the AE1 (band 3) Cl-/HCO3- exchanger.

Distal renal tubular acidosis (dRTA) is characterized by defective urinary acidification by the distal nephron. Cl-/HCO3- exchange mediated by the AE1 anion exchanger in the basolateral membrane of type A intercalated cells is thought to be an essential component of lumenal H+ secretion by collecting duct intercalated cells. We evaluated the AE1 gene as a possible candidate gene for familial dRTA. We found in three unrelated families with autosomal dominant dRTA that all clinically affected individuals were heterozygous for a single missense mutation encoding the mutant AE1 polypeptide R589H. Patient red cells showed approximately 20% reduction in sulfate influx of normal 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid sensitivity and pH dependence. Recombinant kidney AE1 R589H expressed in Xenopus oocytes showed 20-50% reduction in Cl-/Cl- and Cl-/HCO3- exchange, but did not display a dominant negative phenotype for anion transport when coexpressed with wild-type AE1. One apparently unaffected individual for whom acid-loading data were unavailable also was heterozygous for the mutation. Thus, in contrast to previously described heterozygous loss-of-function mutations in AE1 associated with red cell abnormalities and apparently normal renal acidification, the heterozygous hypomorphic AE1 mutation R589H is associated with dominant dRTA and normal red cells.

Acidosis, Renal Tubular↗
PubMed1998

Studies on flower initiation of Super-Dwarf wheat under stress conditions simulating those on the Space Station, Mir.

Super-Dwarf wheat plants were grown in growth chambers under 12 treatments with three photoperiods (18 h, 21 h, 24 h) and four carbon dioxide (CO2) levels (360, 1,200, 3,000 and 7,000 micromoles mol-1). Carbon dioxide concentrations affected flower initiation rates of Super-Dwarf wheat. The optimum CO2 level for flower initiation and development was 1,200 micromoles mol-1. Super-optimum CO2 levels delayed flower initiation, but did not decrease final flower bud number per head. Longer photoperiods not only accelerated flower initiation rates, but also decreased deleterious effects of super-optimum CO2. Flower bud size and head length at the same developmental stage were larger under longer photoperiods, but final flower bud number was not affected by photoperiod.

Carbon Dioxide↗
PubMed1998

Restricted diastolic opening of the mitral leaflets in patients with left ventricular dysfunction: evidence for increased valve tethering.

OBJECTIVES: We tested the hypothesis that patients with incomplete systolic mitral leaflet closure (IMLC: apically displaced coaptation) also have restricted diastolic leaflet opening that is independent of mitral inflow volume and provides evidence supporting increased leaflet tethering. BACKGROUND: Competing hypotheses for functional mitral regurgitation (MR) with IMLC include global left ventricular (LV) dysfunction per se (reduced leaflet closing force) versus geometric distortion of the mitral apparatus by LV dilation (augmented leaflet tethering). These are inseparable in systole, but restricted leaflet motion has also been observed in diastole, and attributed to reduced mitral inflow. METHODS: Diastolic mitral leaflet excursion and orifice area were measured by two-dimensional echocardiography in 58 patients with global LV dysfunction, 36 with and 22 without IMLC, compared with 21 normal subjects. The biplane Simpson's method was used to calculate LV ejection volume, which equals mitral inflow volume in the absence of aortic regurgitation. RESULTS: The diastolic mitral leaflet excursion angle was markedly reduced in patients with IMLC compared with those without IMLC, whose ventricles were smaller, and normal subjects (17 +/- 10 degrees vs. 58 +/- 13 degrees vs. 67 +/- 8 degrees, p < 0.0001). Excursion angle was dissociated from mitral inflow volume (r2 = 0.04); excursion was reduced in patients with IMLC despite a normal inflow volume in the larger ventricles with MR (60 +/- 25 vs. 61 +/- 12 ml in normal subjects, p = NS), and excursion was nearly normal in patients without IMLC despite reduced inflow volume (40 +/- 10 ml, p < 0.001 vs. normal subjects). The anterior leaflet when maximally open coincided well with the line connecting its attachments to the anterior annulus and papillary muscle tip (angular difference = 3 +/- 7 degrees vs. 25 +/- 9 degrees vs. 32 +/- 10 degrees in patients with and without IMLC vs. normal subjects, p < 0.0001). In patients with IMLC, the leaflet tip orifice was smaller in an anteroposterior direction but wider than in the other groups, giving a normal total area (6.8 +/- 1.8 vs. 7.1 +/- 1.2 vs. 6.9 +/- 0.8 cm2, p = NS). CONCLUSIONS: Patients with LV dysfunction and systolic IMLC also have restricted diastolic leaflet excursion that is independent of inflow volume, coincides with the tethering line connecting the annulus and papillary muscle and reflects limitation of anterior motion relative to the posteriorly placed papillary muscles without a decrease in total orifice area. These observations are consistent with increased tethering by displaced mitral leaflet attachments in the dilated ventricles of patients with IMLC that can restrict both diastolic opening and systolic closure.

Adult↗