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Biomedical subjects

L Wan

Publications and source records attributed to L Wan.

At least 73 records · Page 4Linked to original sources
PubMed1995

Evidence for nosocomial transmission of Candida albicans obtained by Ca3 fingerprinting.

The moderately repetitive sequence Ca3 was used to fingerprint Candida albicans isolates from 32 patients hospitalized for more than 3 days, 17 recent admissions or outpatients, and 8 recently readmitted patients and 10 commensal isolates from the community in Wellington, New Zealand, plus isolates from 21 hospitalized patients, 26 outpatients or recent admissions, 4 recently readmitted patients, and 10 healthy individuals in the community in Auckland, New Zealand. In Wellington, isolates from patients hospitalized in Wellington Hospital for more than 3 days were genetically significantly less diverse than were isolates from outpatients or recent admissions or isolates from healthy individuals in the community. In addition, two clusters of genetically similar strains were isolated from hospitalized patients significantly more often than from other individuals. These observations provide evidence (albeit indirectly) for nosocomial transmission of hospital-specific C. albicans strains. In contrast, no indication of hospital-specific transmission of C. albicans was found in Auckland Hospital. Since these results were obtained under conditions in which no candidiasis outbreak occurred in either hospital, they also suggest that Ca3 fingerprinting may be a useful tool in preventive nosocomial infection control programs, allowing assessment of the extent of C. albicans transmission occurring in a hospital.

Adolescent↗
PubMed1995

[Studies on diagnosis of falciparum malaria based on amplifying specific SSUrDNA fragment with nested PCR].

Two pairs of primers specific to small subunit ribosomal DNA of Plasmodium falciparum were designed and the expected SSUrDNA fragment was amplified for detecting P. falciparum infection with double-temperature-nested polymerase chain reaction using DNA prepared by boiling method. The results showed that the nested PCR could amplify a constant size of desired SSUrDNA fragment of P. falciparum which was further confirmed by digestion of restriction endonuclease and could detect parasitemia level of 0.8 x 10(-6). It has great potentials for identifying Plasmodium species in ring form of erythrocytic stage and detecting mixed Plasmodium infections. Therefore, it is suggested that this method is sensitive, accurate, simple and rapid in detecting Plasmodium falciparum in blood samples for malaria diagnosis.

Animals↗
PubMed1995

[Chemical constituents of Stellera chamaejasme L].

Twelve compounds were isolated from the roots of Stellera chamaejasma. Five of them were elucidated by spectroscopic and chemical methods as 3', 14-dimethyl-4', 11-dimethoxy-5, 7-dihydroxybenzoflavanone (10), daphnetin (1), umbelliferone (2), daucosterol (5) and beta-sitosterol (3). Compound 10 is new. Compounds 1, 2, 5, 10 were isolated for the first time from S. chamaejasme.

Benzoflavones↗
PubMed1995

[P-NMR analysis of the hepatic cell energetic metabolism in tumor-bearing mice by moxibustion treatment].

The new technique, NMR (nuclear magnetic resonance) spectrum analysis was used in this research to measure the state of energetic metabolism of hepatic cells at the organic level. The experimental results demonstrated that moxibustion on Guanyuan (CV4) point could remarkably increase the ATP molecules in the hepatic cells, significantly raise the thermodynamic reserve and phosphate potential of the hepatic cells, so as to enhance the functional activities of liver. It is discussed here of the mechanism of anti-tumor by moxibustion treatment and of the theory of warming the kidney and enhancing the Yang to tonify to energetic Qi by moxibustion on Guanyuan point.

Animals↗
PubMed1994

Immunogenicity of the N-glycans of peanut peroxidase.

The three tryptic glycopeptides of cationic peanut peroxidase (C. PRX) and the sole one of anionic peanut peroxidase (A. PRX) were individually coupled to bovine serum albumin to raise antisera. The three categories of antibodies directed towards three N-glycans of C. PRX (anti-GLa, anti-GLb and anti-GLc) were isolated from antisera with glycan-conjugated ECH Sepharose 4B affinity columns and the distribution of epitopes on the N-glycans was investigated. The reactivity of anti-GLa, anti-GLb and anti-GLc is inhibited 25-40% by 1 M fucose, compared with a slight inhibition by N-acetylglycosamine and xylose. Mannose and galactose showed no inhibition to anti-GLa and only a slight inhibition to anti-GLb and anti-GLc. All of anti-GLa, anti-GLb and anti-GLc recognize A. PRX and horseradish peroxidase but do not recognize fetuin. Also, their reactivity is inhibited by bromelain by more than 70%. The three categories of antibodies present high homogeneity and appear to be directed mainly towards the core structure [Xyl] (Man)3 [Fuc] (GlcNAc)2. An effective and simple method to screen antibodies with carbohydrate specificities is described herein.

Animals↗
PubMed1994

Echocardiographic evaluation of bupivacaine cardiotoxicity.

In nine pentobarbital anesthetized dogs, the global effects of bupivacaine on the heart were examined during and after the onset of bupivacaine cardiotoxicity. The onset of bupivacaine cardiotoxicity was followed by the use of echocardiography to determine the sequence of events. The overall sequence of changes in the heart, demonstrated by the echocardiographic images, was markedly impaired systolic function and right ventricular dilation. The right ventricular dilation was so profound that it was associated with a septal shift into the left ventricle. Right ventricular dilation was so profound that the ability to maintain the whole ventricle within the echocardiographic image was lost. Areas obtained from the left ventricle at the two time points studied (the half-time from the beginning of injection to the occurrence of asystole referred to as midway through the toxic episode and at asystole) exhibited a significant systolic dilation only midway through the toxic episode. The mean total dose of bupivacaine resulting in the dilation of the ventricles was 14.0 +/- 3.3 mg/kg. The mean arterial pressure was reduced from control by 46.9% +/- 8.8% midway through the toxic episode. The mean pulmonary arterial pressure exhibited no significant change from before the bupivacaine injection sequence. A variety of conduction changes seen midway through the toxic episode were widening of the QRS complex, inversion, bradycardia, premature ventricular contractions (PVCs), or a combination of these. PVCs, if seen at all, were only beginning to develop and no heart block was seen in any dog midway through the toxic episode.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[The effects of fibronectin on DNA synthesis and ultrastructure of periodontal ligament cells]

Microspectrophotometer and transmitted electron microscope (TEM) were used to study the change of DNA synthesis and ultrastructure after fibronection(FN) acted on cultured periodontal ligament cells (PDLC).The results showed that the data of nuclus area,nuclus total absorbs and nuclus mean absorbs of PDLC in FN group was higher than control(P<0.01).Under the TEM we observed that in FN group there were more euchromatin in cell nuclues and more organ cells such as microfilaments,chondriosomes and endoplasmic reticulum in cytoplasm.It suggested that FN can accelerate periodontal regeneration by promoting DNA and protein synthesis of PDLC.

Journal Article↗
PubMed1994

Differentiation of immortalized epithelial cells derived from cystic fibrosis airway submucosal glands.

Cystic fibrosis (CF) involves abnormalities in mucus production and secretion of the airway. Studies of the regulation of airway mucin production and secretion has been difficult due to the lack of in vitro models of the airway epithelial cells which express functional differentiation. Because the majority of the mucin in the airway is apparently produced by the submucosal glands, we have focused our attention on the development of cell culture models of human airway submucosal glands. This report describes the propagation of CF airway submucosal gland epithelial cells which continue to express mucin production. The CF bronchus was obtained from a 31-yr-old patient who received a double lung transplant. The glands were dissected out and primary cultures prepared by the explant/outgrowth procedure. The cells were immortalized by infection with Ad12-SV40 hybrid virus. The cultures are maintained in serum-free keratinocyte basal medium supplemented with insulin (5 micrograms/ml), hydrocortisone (0.5 microgram/ml), epidermal growth factor (10 ng/ml), bovine pituitary extract (25 micrograms/ml), and antibiotics. Cultures were passaged using 0.125% trypsin in Ca+2 and Mg(+2)-free Hanks', balanced salt solution. Polymerase chain reaction (PCR) analysis demonstrated that the cells were homozygous for the delta F508 mutation. Morphologic observations showed that the cells were epithelial and were interconnected by sparsely distributed desmosomes. Their cytoplasm contained secretory-type structures including abundant Golgi, rough endoplasmic reticulum, and secretory vesicles. Immunofluorescent studies determined that all cells were positive for cytokeratins, mucin glycoconjugates, and cystic fibrosis transmembrane conductance regulator. The cultures secreted substantial amounts of mucin glycoproteins and expressed the MUC-2 mucin gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1994

[Amplification in vitro and identification of small subunit ribosomal DNA fragment of Plasmodium falciparum].

According to computer analysis of SSUrDNA sequences of Plasmodium, other protozooa and human, two oligonucleotide primers were designed. A DNA fragment, about 570 base pairs, was successfully amplified by two temperature point polymerase chain reaction from the genomic DNA of cultivated erythrocytic stage of P. falciparum FCC/YN (Simao), but no fragment was obtained from that of P. vivax, L. donovani, T. gondii and humans. It has been confirmed that the amplified fragment was indeed expected SSUrDNA segment of P. falciparum by means of restriction endonuclease digestions and Northern blot hybridization.

Animals↗
PubMed1994

[Cytological study on the effect of fibronectin in promoting periodontal regeneration].

Cell cultures and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] colorimetric assay were used to observe the different biological effects of fibronectin (FN) on periodontal ligament (PDL) cells and gingival fibroblasts (GF). The results showed that FN has the capacity to accelerate PDL cell multiplication at dose 0.044 mumol/L, and accelerate GF multiplication at does from 0.089 mumol/L to 0.178 mumol/L. It suggests that PDL cells are more susceptible to FN than GF. So, the right amount of FN might promote the PDL cells to occupy root surface firstly and multiply, differentiate, and then to form a new connective tissue attachment.

Adolescent↗
PubMed1993

A study on glycosylation of cationic peanut peroxidase.

Cationic peroxidase from a cell suspension culture has two heterogeneously glycosylated forms, based on their Concanavalin A column binding property, namely CP-and CP+. In these two forms three out of five potential glycosylation sites are used. Asn60 and Asn185 are located in hydrophilic beta-turns, while Asn144 in a hydrophobic beta-sheet. Asn209 and Asn275 lacking glycans all have a proline residue at the C-terminal of the consensus sequence. The difference between CP- and CP+ is due to the heterogeneous glycosylation at individual glycosylation sites.

Amino Acid Sequence↗
PubMed1993

[Amplification, cloning and sequence analysis of a SSUrRNA gene fragment of Plasmodium vivax isolates from Yunnan Province].

According to known SSUrDNA sequences of Plasmodium vivax, correlated protozoa and human being, sequences of oligonucleotide primers were defined with computer programming. Specific SSUrDNA fragment of P. vivax, about 640 bp in length, was directly amplified by two temperature point polymerase chain reaction from extracted genomic DNA of two blood samples of vivax malaria patients from Yunnan Province. Using dideoxynucleotide terminator method, the sequences of amplified DNA fragments were determined separately and showed no difference between the two samples. However, comparison of the sequence reported by Waters AP and McCutchan TF (1989) and that of amplified fragment of Yunnan P. vivax isolates revealed the existence of nucleotide substitution and deletion which occurred respectively in the sites 269 and 630, and resulted in the change of restriction map.

Animals↗
PubMed1992

Characterization of two forms of cationic peroxidase from cultured peanut cells.

Two forms of cationic peroxidase from peanut cells were differentiated by concanavalin A affinity chromatography. They differed in molecular mass as well as concanavalin A binding, leading to the initial suggestion that they represented two isozymes of peroxidase. However, similar values for the specific activity, Soret absorption, calcium content, and peptide molecular mass were observed for each of the forms. Therefore, the binding and nonbinding fractions most likely represent two molecular forms of cationic peanut peroxidase, rather than two distinct cationic isozymes. The difference between these two forms is discussed in terms of glycosylation. Through the amino acid sequence analysis of the formic acid treated peptide, the cationic isozyme has been shown to be identical in amino acid sequence to the cDNA clone PNC1.

Arachis↗
PubMed1989

A rare case of 68,XX triploidy diagnosed by amniocentesis.

68,XX triploidy was found in the amniotic fluid cell culture of a 40-year-old patient. Elective termination of the pregnancy revealed a fetus with multiple congenital anomalies. While this case does show some common features with monosomy X, a greater similarity to the triploidy syndrome is observed.

Abnormalities, Multiple↗
PubMed1974

Prostaglandins stimulate thyroid function in pregnant women.

Intravaginal or intravenous administration of prostaglandin F(2alpha) to pregnant women produced significant elevations of plasma triiodothyronine and thyroxine concentrations, but no rise of thyrotropin. These observations are consistent with those of previous in vitro studies indicating that prostaglandins can act directly on the thyroid gland to stimulate thyroid hormone synthesis or release, or both.

Female↗