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Biomedical subjects

Q D Nguyen

Publications and source records attributed to Q D Nguyen.

26 records · Page 2Linked to original sources
PubMed1998

Quantitative analysis of cholesterol and cholesteryl esters in human atherosclerotic plaques using near-infrared Raman spectroscopy.

Raman spectroscopy is a non-destructive analytical technique and previous results have shown that qualitative analysis of the lipid component of human atheromatous arteries is feasible. In this paper, we describe a quantitative analytical method for cholesterol and cholesteryl esters in human atherosclerotic plaques, combined with Raman spectroscopic results, using partial least-squares (PLS) regression, a statistical multivariate method based on factorial analysis. Twenty-nine human atherosclerotic pooled samples were studied and the results of Raman spectroscopy coupled with the PLS method were compared to biochemical results. The standard error of prediction was 16.1, 13.6, 1.9, 3.3 and 3.4 mg/g for total cholesterol, free cholesterol, palmitate cholesteryl, oleate cholesteryl and linoleate cholesteryl, respectively. The repeatability of Raman spectroscopy was found to be excellent. Our results show that Raman spectroscopy is a promising technique to obtain a consistent and non-destructive quantitative analysis of cholesterol and cholesteryl esters in human atherosclerotic lesions. In situ and in vivo analysis is a possibility in the near future.

Aged↗
PubMed1998

Angiotensin II type 1 receptor A1166C gene polymorphism. Absence of an association with the risk of coronary artery disease and myocardial infarction and of a synergistic effect with angiotensin-converting enzyme gene polymorphism on the risk of these diseases.

AIM: There is evidence that interaction between angiotensin II type 1 receptor A1166C gene polymorphism and angiotensin I-converting enzyme Insertion/Deletion gene variation might have an effect on the risk of myocardial infarction. The study was carried out in a population of 2244 male Caucasians, whose coronary anatomy was defined by means of coronary angiography. We analysed the relationship, on the risk of ischaemic heart disease, of angiotensin II type 1 receptor A1166C gene variation, not only to myocardial infarction but also to coronary artery disease, and its potential interaction with angiotensin I-converting enzyme Insertion/Deletion gene polymorphism. METHODS AND RESULTS: No association was detected between angiotensin II type 1 receptor A1166C gene polymorphism and coronary artery disease. Similarly, there was no link to myocardial infarction, either in the total population or in low risk groups. In addition, most importantly, we found no interaction between angiotensin II type 1 receptor A1166C gene variation and angiotensin I-converting Insertion/Deletion polymorphism, either in connection with the risk of coronary artery disease or myocardial infarction. CONCLUSION: This angiotensin II type 1 receptor A1166C gene variation is not associated with any detectable increase in risk of ischaemic heart disease. The findings of the present study do not suggest that, as regards risk of coronary artery disease and myocardial infarction, there is interaction between gene polymorphism and angiotensin I-converting enzyme Insertion/Deletion gene variation.

Aged↗
PubMed1998

Ciliary body melanoma masquerading as chronic uveitis.

PURPOSE: To report a case of ciliary body melanoma that masqueraded as chronic uveitis. METHODS: A patient experienced persistent unilateral panuveitis and elevated intraocular pressure. Inflammation and pressure worsened after cataract extraction and lens implantation. Diagnostic vitrectomy was non-revealing. RESULTS: Repeat vitrectomy and lens implant removal revealed a ciliary body mass, suggestive of melanoma. Ultrasonography and clinical evaluation by the retinal oncologists supported this diagnosis. The uveitis persisted despite aggressive medical treatments, including methotrexate. Proton beam irradiation of the melanoma led to resolution of uveitis and restoration of normal intraocular pressure. CONCLUSION: Ciliary body melanoma can present as chronic uveitis and refractory glaucoma.

Cataract Extraction↗
PubMed1998

Extracapsular cataract surgery in Vietnam: a 1 year follow-up study.

PURPOSE: Unoperated cataract is the leading cause of blindness in the developing world. Many developing countries now use extracapsular cataract extraction (ECCE) with intra-ocular lens insertion (IOL) in their cataract blindness-prevention programmes. To date, little research has been directed at visual outcomes and complication rates of ECCE/IOL surgery in developing countries. METHODS: We conducted a follow-up study of 155 eyes approximately 12 months after ECCE/IOL surgery by eight local eye surgeons in Central Vietnam. We report the findings for the 144 eyes (93%) successfully reviewed. All subjects underwent manual ECCE with insertion of a three-piece posterior chamber IOL. All eyes were also assessed for the presence and severity of posterior capsule opacification (PCO) using a newly developed grading system. RESULTS: Overall, 110 eyes (75%) had uncorrected visual acuities > or = 6/24 and 107 eyes (74%) had best spherically corrected visual acuities > or = 6/18. Some degree of PCO was found in 40% of eyes, but was graded as visually significant in only 4% of eyes. No major sight-threatening complications were noted. A portable neodymium:yttrium aluminium garnet (Nd:YAG) laser was used to perform capsulotomies on all eyes with visually significant PCO. There were no laser complications noted. CONCLUSIONS: At approximately 1 year after ECCE/IOL, the visual outcomes for subjects in this cohort were favourable and complication rates were low. Posterior chamber opacification was not a major cause of vision impairment in this cohort. Portable Nd:YAG lasers may provide an effective solution to the problem of visually significant PCO occurring in developing countries as a late complication of extracapsular surgery. These findings support an increasing role for ECCE/PCIOL surgery by trained local eye surgeons in developing countries.

Adolescent↗
PubMed1998

Association of the platelet glycoprotein IIIa PlA1/A2 gene polymorphism to coronary artery disease but not to nonfatal myocardial infarction in low risk patients.

BACKGROUND: The platelet membrane glycoprotein IIb/IIIa functions as a receptor for fibrinogen and von Willebrand factor during platelet aggregation. In a small case-control study, evidence has been presented that the PlA2 allele of the platelet glycoprotein GPIIIa PlA/A2 gene polymorphism might be an independent risk factor for acute myocardial infarction (MI). METHODS AND RESULTS: We explored the association of the PlA1A2 to the severity of coronary artery disease (CAD), as assessed angiographically in 2252 male individuals, and to myocardial infarction (MI). The severity of coronary heart disease (CHD) was also estimated by calculating a CHD score according to Gensini. The PlA genotype was determined by allele specific restriction digestion. Relation of the PlA2 allele to CAD: In the total population, the frequency of the PlA2 allele was not associated to the presence or to the extent of CAD. Also the CHD scores of PlA1/PlA2 genotypes were essentially the same. However, after exclusion of individuals with high BMI (> or =26.9 kg/m2) and/or low apoAI (< 1.43 g/l) PlA2PlA2 carriers had clearly higher CHD scores than PlA1PlA1 genotypes: PlA1PlA2 heterozygotes had intermediate values (p <0.05). After division of the study population into one group of individuals without any angiographic signs of CAD (CHD score = 0) and into another group of patients with severe CAD (CHD score (> or = 120), a strong association of the PlA2 allele with severe CAD was also found in the same low risk groups: e.g. exclusion of persons with high BMI and low apoAI resulted in an Odds ratio of 5.37 (1.46-19.7) (p <0.02). Relation of the PlA2 allele to MI: No association was found between PlA1/PlA2 genotypes and risk of MI neither in the total population nor in low risk subgroups. CONCLUSIONS: Whereas no difference in the distribution of allele and genotype frequencies between controls and survivors of MI could be detected, the PlA2 allele is associated with CHD in low risk patients.

Aged↗
PubMed1996

Cicatricial pemphigoid: diagnosis and treatment.

Cicatricial pemphigoid is a systemic autoimmune disease with both ocular and extraocular manifestations. Its effect on the eyes is characterized by chronic cicatrizing conjunctivitis and progressive conjunctival sub-epithelial fibrosis with resultant fornix foreshortening, symblepharon formation, trichiasis, meibomian, and lacrimal duct obstruction resulting in sicca syndrome, ocular surface keratinization, and eventually blindness. Extraocular manifestations include stricture formation of the esophagus, trachea, anus, or vagina. OCP is characterized by deposition of immunoreactants at the conjunctival basement membrane zone, initiating a type II hypersensitivity reaction. Demonstration of this deposition can be done using immunofluorescence or immunoperoxidase technique.

Autoimmune Diseases↗
PubMed1990

Molecular and developmental analyses of the protein encoded by the Drosophila gene ectodermal.

The Drosophila gene ectodermal (ect, located at 67D8-10 on chromosome 3) is expressed for a short period at mid-embryogenesis in all ectodermally derived tissues except the nervous system. During this stage the tissues involved form tubular structures by a process of invagination followed by cell fusion. Here we report the sequence of the ect protein as deduced from the longest ORF (280 codons) of an ect cDNA. The principal molecular features of the ect protein are: 1) a consensus leader sequence for targeting to the rough ER; 2) a central domain containing a remarkably high density of acidic residues arranged in large clusters separated by smaller clusters of hydrophobic residues; 3) a consensus nuclear-targeting sequence near the C-terminus; 4) a single tyrosine residue located at a potential tyrosine-sulfation site. The antibody staining pattern of the ect protein corresponds to the in situ hybridization pattern of the transcript. A possible role for the ect protein in the complex process of tubular formation that occurs in embryonic ectodermal tissues is discussed.

Amino Acid Sequence↗