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Biomedical subjects

A M Wang

Publications and source records attributed to A M Wang.

At least 19 recordsLinked to original sources
PubMed2007

Selective removal of organochlorine pesticides (OCPs) from aqueous solution by triolein-embedded composite adsorbent.

A novel composite adsorbent (CA-T) was used for the selective removal of organochlorine pesticides (OCPs) from aqueous solution. The adsorbent was composed of the supporting activated carbon and the surrounding triolein-embedded cellulose acetate membrane. Scanning electron microscopy (SEM), N2 adsorption isotherms and fluorescence methods were used to characterize the physicochemical properties of CA-T. Triolein was perfectly embedded in the cellulose acetate membrane and deposited on the surface of activated carbon. The adsorbent was stable in water and no triolein leakage was detected during the test periods. Some organochlorine pesticides (OCPs), such as dieldrin, endrin, aldrin, and heptachlor epoxide, were used as model contaminants and removed by CA-T in laboratory batch experiments. The adsorption isotherm followed the Freundlich equation and the kinetic data fitted well to the pseudo-second-order reaction model. Results also indicated that CA-T appeared to be a promising adsorbent with good selectivity and satisfactory removal rate for lipophilic OCPs from aqueous solutions when present in trace amounts. The adsorption rate and removal efficiency for lipophilic OCPs were positively related to their octanol-water partition coefficients (log K(ow)). Lower residual concentrations of OCPs were achieved when compared to granular activated carbon (GAC).

Adsorption↗
PubMed2001

A clinical comparison of the safety and efficacy of MultiHance (gadobenate dimeglumine) and Omniscan (Gadodiamide) in magnetic resonance imaging in patients with central nervous system pathology.

RATIONALE AND OBJECTIVES: The safety and diagnostic efficacy of MultiHance (gadobenate dimeglumine) in the central nervous system (CNS) were evaluated in a double-blind, multicenter, phase III clinical trial. METHODS: Two hundred five patients highly suspected of having a CNS lesion (by previous imaging exam) were enrolled at 16 sites in the United States. Patients were randomized to one of three incremental dosing regimens. Magnetic resonance imaging with Omniscan (gadodiamide) at doses of 0.1 and 0.3 mmol/kg was compared with MultiHance (gadobenate dimeglumine) at doses of 0.05 and 0.15 mmol/kg and at 0.1 and 0.2 mmol/kg. RESULTS: Compared with predose images alone, efficacy was demonstrated in each of the gadobenate dimeglumine and gadodiamide groups (single and cumulative doses) as indicated by the level of diagnostic information, number of lesions detected, and contrast-to-noise ratio measurements. The level of diagnostic information from gadobenate dimeglumine at 0.1 mmol/kg was equivalent to that with gadodiamide at the same dose. One of the two blinded reviewers found equivalence between the gadobenate dimeglumine 0.05 mmol/kg dose and gadodiamide at 0.1 mmol/kg. Both reviewers found the level of diagnostic information to be equivalent after the second dose of contrast for all three dosing regimens. The cumulative doses of gadobenate dimeglumine were well tolerated and as safe as gadodiamide. CONCLUSIONS: Gadobenate dimeglumine is comparable to gadodiamide in terms of safety and efficacy for imaging of CNS lesions, with a possible advantage in imaging applications owing to enhanced T1 relaxivity.

Brain Neoplasms↗
PubMed2001

Nicotine-induced contraction in the rat coronary artery: possible involvement of the endothelium, reactive oxygen species and COX-1 metabolites.

Nicotine caused a contraction of the rat coronary artery in the presence of Nomega-nitro-L-arginine methyl ester (L-NAME) and arachidonic acid, and did not in the absence of these agents. The present experiments were undertaken to pharmacologically characterize the nicotine-induced contraction in ring preparations of the rat coronary artery. The contraction was abolished by chemical removal of endothelium saponin. Oxygen radical scavengers, superoxide dismutase and catalase, significantly attenuated the contraction. Cyclooxygenase-1 (COX-1) inhibitors (flurbiprofen, ketoprofen and ketrolack) attenuated the nicotine-induced contraction in a concentration-dependent manner, and cyclooxygenase-2 (COX-2) inhibitors at high concentrations (nimesulide and NS-389) slightly attenuated the contraction. A TXA2 synthetase inhibitor (OKY-046) attenuated the contraction to a small extent only at high concentrations. A TXA2 receptor antagonist (S-1452) attenuated the contraction in a concentration-dependent manner. A nicotinic receptor antagonist (hexamethonium) attenuated the contraction in part and an alpha-adrenoceptor antagonist (prazosin) nearly abolished the contraction. From these results, it was suggested that the contraction induced by nicotine in the rat coronary artery in the presence of L-NAME and arachidonic acid is endothelium dependent, and involves reactive oxygen species and endothelial COX-1 metabolites of arachidonic acid. Part of the contraction is probably due to release of norepinephrine.

Animals↗
PubMed2000

Paraganglioma of the temporal bone: role of magnetic resonance imaging versus computed tomography.

Paragangliomas, also known as glomus tumors or chemodectomas, are tumors arising from chemoreceptor tissue (paraganglia), which are neural crest in origin and found in higher concentration along the glossopharyngeal and vagal cranial nerve. Three types of paragangliomas are related with the temporal bone: glomus tympanicum, glomus jugulare, and glomus vagale. The role of computed tomography (CT) and magnetic resonance imaging (MRI) in diagnosing these types of tumors is discussed, along with the importance of arteriography in aiding the diagnosis and treatment. This article discusses the choice between CT and MR based on clinical symptoms and tumor location, and illustrates the newest CT, MR, and angiography applications. A brief discussion on treatment options is given.

Angiography↗
PubMed2000

Use of carnosine as a natural anti-senescence drug for human beings.

Carnosine is an endogenous free-radical scavenger. The latest research has indicated that apart from the function of protecting cells from oxidation-induced stress damage, carnosine appears to be able to extend the lifespan of cultured cells, rejuvenate senescent cells, inhibit the toxic effects of amyloid peptide (A beta), malondialdehyde, and hypochlorite to cells, inhibit glycosylation of proteins and protein-DNA and protein-protein cross-linking, and maintain cellular homeostasis. Also, carnosine seems to delay the impairment of eyesight with aging, effectively preventing and treating senile cataract and other age-related diseases. Therefore, carnosine may be applied to human being as a drug against aging.

Aging↗
PubMed2000

[Research progress on preservation of severed limbs].

OBJECTIVE: To define how to preserve the severed limbs to prolong the period of replantation. METHODS: The original articles about preservation of severed limbs in recent years were reviewed, it was suggested that the period of replantation was determined by the injury of skeletal muscle. RESULTS: When the environment of severed limbs was changed, the injures of skeletal muscle could be decreased. CONCLUSION: After the severed limbs are reasonably preserved, the period of replantation may be prolonged.

Animals↗
PubMed2000

[Determination of phenols in environmental water with bromination derivatization and gas chromatography].

A method for the determination of phenols in environmental water with bromination derivatization and gas chromatography is described. The phenols were transformed to bromophenols and then extracted with toluene and separated by the FFAP wide-bore capillary column and detected by electron capture detector (ECD). The results showed that the linear ranges were 0.06-80 micrograms/L for o-methylphenol and p-methylphenol, 0.03-40 micrograms/L for phenol and m-methylphenol. The detection limits for o-methylphenol, p-methylphenol, phenol and m-methylphenol were 0.03, 0.06, 0.01, 0.015 microgram/L respectively. The method is simple, rapid and reliable for determining phenols in environmental water.

Chromatography, Gas↗
PubMed1998

Murine alpha-N-acetylgalactosaminidase: isolation and expression of a full-length cDNA and genomic organization: further evidence of an alpha-galactosidase gene family.

Recent characterization of the human sequences encoding two lysosomal hydrolases, alpha-galactosidase A (alpha-Gal A) and alpha-N-acetylgalactosaminidase (alpha-GalNAc) revealed that these two enzymes with distinct enzymatic activities shared about 50% overall amino acid identity and that their genomic sequences had a conserved common gene structure. These findings suggested that these genes, which are located on different chromosomes, arose by duplication and divergence from a common ancestral gene. To further compare this alpha-galactosidase gene family, the murine alpha-GalNAc cDNA and genomic sequences were isolated and characterized. The full-length cDNA contained an open-reading frame of 1245 bp encoding a 415 amino acid polypeptide and had 5' and 3' untranslated regions of 94 and 333 bp, respectively. The coding region had 81% nucleotide and 81.9% amino acid identities with those of the corresponding human alpha-GalNAc sequence. Northern analysis revealed a single transcript of approximately 1.9 kb. The functional integrity of the cDNA was demonstrated by transient expression in COS-1 cells. The murine alpha-GalNAc genomic sequence spanned approximately 9 kb and was identical in structure with the human alpha-GalNAc gene with eight introns interrupting the coding sequence at identical positions. In addition, the deduced amino acid sequence of the murine alpha-GalNAc gene was highly homologous with alpha-GalNAc and alpha-Gal A genes from other species providing further support for a common evolutionary ancestor of the alpha-galactosidase gene family. The availability of the murine gene will permit additional evolutionary comparisons, structure/function analyses, and the generation of mice with alpha-GalNAc deficiency by gene targeting.

Amino Acid Sequence↗
PubMed1997

Multifocal cerebral hemorrhage in eclampsia and severe pre-eclampsia.

Eclampsia and severe pre-eclampsia have often been associated with transient cortical blindness and with bilateral occipital CT hypodensities or increased T2-weighted signal abnormalities on MRI. Petechial hemorrhages have been reported pathologically and on MRI, but major hemorrhages have been infrequent. Symptoms and radiologic findings are usually reversible and the prognosis good. We reviewed the clinical and radiologic findings in four patients with eclampsia or severe pre-eclampsia who had multifocal cerebral hemorrhages found acutely on CT. Hemorrhages were usually bilateral and often in posterior areas. Two patients had hemorrhages discovered after earlier normal scans. One patient died, and others had prolonged neurologic residua including visuospatial and other cognitive deficits. The posterior CT and MRI abnormalities in eclampsia and severe pre-eclampsia are not always benign and reversible but may precede or include multifocal hemorrhages with long-term neurologic complications. The affected areas suggest an increased posterior circulation vulnerability to the hypertensive vascular disease of eclampsia.

Adult↗
PubMed1997

MRA of venous sinus thrombosis.

Intracranial venous magnetic resonance angiography (MRA) provides excellent visualization of dural venous sinuses and large deep and superficial cerebral veins noninvasively. It is a very useful imaging technique to evaluate venous sinus thrombosis. It also provides the planning and monitoring endovascular thrombolytic treatment for dural sinus thrombosis. Familiarization with normal intracranial venous anatomy and its normal variants as well as recognition of its pitfalls and artifacts of the venous MRA techniques are critical for making interpretation of venous sinus thrombosis correctly.

Humans↗
PubMed1996

The entire genomic sequence and cDNA expression of mouse alpha-galactosidase A.

The full-length cDNA and genomic sequences encoding mouse alpha-galactosidase A (alpha-Gal A; EC 3.2.1.22), a lysosomal galactohydrolase, were isolated and characterized. The cDNA's open reading frame encoded 419 amino acids and had 82% nucleotide (nt) and 78% amino acid identity with the human sequence, although the carboxy terminus of the mouse alpha-Gal A polypeptide was 10 amino acids shorter. The functional integrity of the mouse cDNA was demonstrated by transient expression in COS-1 cells. Northern analysis revealed two mRNA species of about 1.6 and 3.4 kb due to alternative polyadenylation signals. The entire 14.4-kb mouse genomic sequence was determined; each of its seven exons was interrupted by intronic sequence at the identical positions as the exons in the human gene. The mouse 5' flanking region (250 nt) had one Sp1, site, five CAAT boxes, and no TATA box and had 67% identity with the human promoter region. The gene contained 18 complete or partial Alu-repetitive elements (13 type 1 and 5 type 2 repeats), and three putative functional AATAAA consensus polyadenylation signals were identified 72, 1668, and 1682 nt after the TAA termination codon. Use of the 72-nt site and the 1866 and/or 1682 sites were consistent with the shorter and longer transcripts. The availability of the full-length cDNA and genomic sequence encoding mouse alpha-Gal A should facilitate structure/function studies of this lysosomal glycosidase and the construction of alpha-Gal A-deficient mice by targeted gene disruption.

Amino Acid Sequence↗
PubMed1996

Expression of primary cilia in mammalian cells.

Mammalian cells in vivo frequently express primary cilia. Although some fully differentiated cell types rarely, if ever, express them, most do, indicating that they are regular cell organelles. Their expression can also be explored in vitro, where conditions--physical and chemical, intrinsic and extrinsic--permit experimental approaches which give far greater control than in vivo. This 'state of the art' paper covers briefly the general biology of primary cilia, highlights the current situation with regard to our understanding of their relevance and importance in cell biology from various facets of our recent research, much of it in collaboration with other laboratories world-wide, and outline future work aimed at answering some basic and applied questions about them, within a context of an increasing awareness that signalling between cells is of the utmost importance in understanding proliferation control and its value in cancer research, the major remit of this unit.

Animals↗
PubMed1996

Primary cilium expression in cells from normal and aberrant human skin.

Primary cultures of diploid fibroblasts from human skin have a high incidence of primary cilia associated with their centrosomal centrioles, particularly in stationary phase ("quiescent") cultures. Their progenitor cells in vivo have this same high incidence. Repeated subculturing to > 25 generations did not significantly alter the frequency of expression of cilia. The expression of ciliation remained largely unaffected in fibroblasts grown in culture from cases of hypertrophic scar and keloid, but generally run at a marginally lower level. In contrast, keratinocytes--which have an equally high incidence of primary cilium expression in vivo--seldom express primary cilia in vitro, a distinction most clearly seen when both cell types were present within the same culture. Fibroblasts grown in keratinocyte medium at low total Ca++ concentration ( < 2 x 10-5 M) possessed the same high incidence of ciliation as cells in high Ca++ medium (concentration 1-2.5 x 10-3 M). Increased Ca++ levels in the medium, which induced differentiation of keratinocytes from their low calcium proliferative state, were accompanied by a small increase in the expression of primary cilia over 23 h. The divergent abilities of different cell types in primary culture obtained from a common origin, i.e. skin biopsies, to develop primary cilia are demonstrated, opening up avenues for exploration of factors required for their expression in culture.

Adult↗
PubMed1995

[Clinical observation of the effect of blood gas with two different methods of sputum suction].

The authors observed the preventive effect of the oxygen supplied double channel sucker on low blood oxygen. Thirty patients with channel sputum sucker under the mechanical respiratory support were taken as the contrast group, in comparison with the experimental group A and B respectively. Patients (n = 30) with one channel sputum sucking for 15 sec. were designated as experimental group A, while the other patients (n = 30) with the oxygen supplied double channel sucking for 15 sec were the group B, Blood gas analysis was done in every patient of each group. Significant difference of PO2 was found between group A and the contrast group (P < 0.01). No significant difference was found between group B and the contrast group (P > 0.05). It shows that oxygen supplied double channel sucker has preventive effect on low blood oxygen, and is suitable for sputum sucking in severe patients.

Blood Gas Analysis↗
PubMed1995

Inhibition of kainic acid binding to glutamate receptors by extracts of Gastrodia.

S-(4-hydroxybenzyl)glutathione was isolated as the major principle responsible for the inhibition of the in vitro binding of kainic acid to brain glutamate receptors by water extracts of the plant Gastrodia elata. The affinity (IC50 value) of the compound is slightly lower compared to glutamate and glutathione.

Drugs, Chinese Herbal↗
PubMed1995

Langerhans cell histiocytosis involving the sphenoid sinus and superior orbital fissure.

We report Langerhans cell histiocytosis involving the sphenoid sinus and extending to the orbital apex. MR and CT imaging, particularly with contrast, both were helpful in defining the extent of the lesion before treatment. MR was a useful examination for follow-up after treatment. Langerhans cell histiocytosis should be considered in the differential diagnosis of lesions of this region in the pediatric age group.

Adolescent↗