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PubMed2007

Expression of VCA (viral capsid antigen) and EBNA1 (Epstein-Barr-virus-encoded nuclear antigen 1) genes of Epstein-Barr virus in Pichia pastoris and application of the products in a screening test for patients with nasopharyngeal carcinoma.

EBV (Epstein-Barr virus) serological tests have been used for many years as accessory diagnostic predictors of NPC (nasopharyngeal carcinoma). To date, IF (indirect immunofluorescence) assays still serve as the 'gold standard' for EBV serodiagnosis. However, IF assays are time-consuming, unsuitable for automatic handling and difficult to standardize. This makes their application in mass screening of populations inconvenient. Some of the technical difficulties associated with IF have been overcome by the development of specific ELISAs, but, at present, high sensitivity and specificity cannot be achieved simultaneously by using recombinant protein-based ELISAs, as the diagnostic value of different fragments of EBV in NPC is different. In an attempt to determine a suitable recombinant EBV protein for diagnostic purposes, fragments of EBV VCA (viral capsid antigen) and EBNA1 (Epstein-Barr-virus-encoded nuclear antigen 1) genes were expressed in the methylotrophic yeast Pichia pastoris, and a novel ELISA was established using P. pastoris-expressed VCA-BALF4 [aa (amino acids) 287-623; the BALF4 gene encodes the EBV glycoprotein gp125], EBNA1 (aa 390-641) and VCA-BFRF3 (the gene BFRF3 encodes a viral structural capsid protein or tegument protein VCA p18) proteins. Serum samples were collected from patients with NPC and healthy controls and were tested using this ELISA. The sensitivity of VCA-BFRF3, VCA-BALF4 and EBNA1 tests in the NPC sera were 65.0 (195/300), 76.3 (229/300) and 81.4% (244/300) respectively, whereas the specificity of normal individuals were 92 (460/500), 96 (480/500) and 95.8% (479/500). The optimum combination is VCA-BALF4 plus EBNA1, which identified 90.3% (271/300) of the NPC patients and had a specificity of 92.8% (464/500) for normal individuals. The results obtained from the evaluation of three antibodies to EBV as markers for detecting NPC suggests that a combination of EBNA1 (aa 390-641) and VCA-BALF4 (aa 287-623) assays would give better results in screening for NPC.

Adult↗
PubMed1979

[Evaluation of screening for uterine cervix cancer: from theory to practice (author's transl)].

In many regions, screening for cervical cancer activities by means of cytology have developed "on faith", without fulfilling sufficient quality criteria (identification--smear taking--staining--reading--nomenclature of ciagnosis--communication with the practitioner). Progress made in cytological diagnosis and better knowledge epidemiological data make, at present, such a situation inacceptable from the point of view of public health expenses, as well as for the population of women concerned. Thorough evaluation of this problem shows that inadequate programmes could be more harmful than useful. It is then indispensable to evaluate the needs, then to create technical structures of good quality, before starting any mass screening campaign.

Adult↗
PubMed2002

Hyphenation of capillary high-performance liquid chromatography with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for nano-scale screening of single-bead combinatorial libraries.

This paper focuses on the technical aspects of chemical screening from 384-well plate nano-scale single-bead combinatorial libraries. The analytical technique utilized is a combination of capillary liquid chromatography with ultraviolet detection and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The HPLC/MALDI-MS hyphenation is achieved by means of a micro-fraction collector with a peak detection system that automatically collects the peaks onto the MALDI targets for subsequent characterization. Several experimental parameters such as type of 384-well plate, well-plate sealing foils, and a column-switching procedure were investigated using a small test library of nine components. Additionally, the influence of different MALDI matrices, different MALDI targets and sample-spotting techniques on the MALDI detection sensitivity as well as the ruggedness and sample throughput capacity of this technique were studied. Optimum results for the analytes investigated were obtained with 2,5-dihydroxybenzoic acid using on-line mixing of HPLC effluent and matrix solution. To demonstrate the potential of this capillary HPLC/MALDI-TOFMS method, its application to several single-bead libraries was investigated. The instrumental method allowed for the rapid identification and purity assessment of combinatorial libraries with detection limits down to the higher femtomole level using both UV detection and MALDI mass spectrometry.

Journal Article↗
PubMed1979

[Contact thermography in the early diagnosis of tumors of the breast].

After a brief review of thermal physics and physiology, the authors explain the applications of cholesterol ester plates in the study of breast malignancy. Accumulated experience plus the fruits of statistical studies conducted in leading centers, make it advantageous to use contact thermography not only for the early diagnosis of breast malignancy but also for mass screening of the general population. In competent hands, this technic yields accurate and dependable diagnosis; the method is completely harmless to patient and physician and can be used as many times as needed; and in addition, the method is economical both in terms of time consumed and of actual cost of materials. The new method does not supersede roentgenological investigation indiscriminately but confines it to cases that remain doubtful or suspicious after clinical and thermographic examination.

Breast Neoplasms↗
PubMed1989

Drug testing: technical complications of a complex social issue.

To control the adverse effects of substance abuse, urinary drug testing has become common practice in some occupational settings. Although it is virtually impossible to assess accurately the impact of drug abuse at work, increased accidents and absenteeism as well as impaired productivity have been attributed to drug abuse. The major analytical techniques used to screen for illegal drug use are thin-layer chromatography and enzyme- and radioimmunoassays. Gas chromatography-mass spectrometry is uniformly recommended to confirm any positive screening test. The major technical problem in interpreting screening tests is that the presence of a substance in the urine indicates merely exposure to the drug, not necessarily intoxication, habituation, or addiction. Since no certifying criteria are available to insure quality control among laboratories performing urinary drug testing, results may vary widely. In fact, a study conducted by the Centers for Disease Control suggests that poor performance of some laboratories may adversely affect the treatment of drug abuse. The Federal Rehabilitation Act (1973, section 504) prohibits discrimination against the handicapped, which includes both drug abuse and alcoholism. Legal challenges to urinary drug testing have focused on issues related to the right to privacy and freedom from unreasonable searches. Because of the wide-ranging legal, ethical, and medical ramifications of drug-screening programs, careful review of these issues is recommended before an organization establishes such a program.

Alcoholism↗
PubMedDate not supplied

Feasibility of cytology-based cervical cancer screening in rural Cameroon.

OBJECTIVE: To determine the prevalence of cervical cancer and its precursors in a rural population in Cameroon and to evaluate the feasibility of a cytology-based screening program in such areas. STUDY DESIGN: A prospective study was conducted in the rural town of Bafang. Following an advocacy campaign, 750 women were recruited. After a clinical examination, all women had a Pap smear with the Cervex Brush. Each sample had two preparations, conventional and liquid based. The conventional smears were interpreted in Bafang. Cytologically abnormal cases, those with clinical inflammation and/or macroscopic cervical lesions, had a colposcopic examination and directed biopsy. HSIL and colposcopically abnormal cases were treated with large loop excision of the transformation zone (LLETZ). The liquid-based preparations and histopathology were performed in Geneva and the results sent to Cameroon for patient follow-up. RESULTS: Mean age and parity of the women screened were 43.7 years and 7.8, respectively. The conventional smears showed 3.6% cervical abnormalities: 2% (15/740) ASCUS/LSIL and 1.6% (12/740) HSIL. The liquid-based preparations showed 12.6% (91/722) cervical abnormalities: 10.1% (73/722) ASCUS/LSIL and 2.5% (18/722) HSIL. Fifty percent of samples in both preparations showed evidence of inflammation. Histology was performed on 64 colposcopically directed punch biopsies and LLETZ specimens. The histologic diagnoses agreed with the cytologic findings in 60% (14/23) of conventional smears and 85% (12/14) of liquid-based preparations. CONCLUSION: There is a high rate of cervical intraepithelial neoplasia in the unscreened rural population of Cameroon. The situation is complicated by a high rate of cervical infection. A population-based cytologic screening program for cervical cancer would not be feasible in rural Cameroon because of high cost, low quality and limited technical facilities. Rural Africa requires an algorithm using a simple, low-cost technique of mass screening and an improved cytology service only to triage selected patients.

Adult↗
PubMed1992

Sonographic imaging of the thyroid gland in congenital hypothyroidism.

We have attempted to facilitate differential diagnosis of etiological types of congenital hypothyroidism using real-time ultrasonography. Sonography of the thyroid gland was performed on 418 normal children, and 23 patients with congenital hypothyroidism and hyperthyrotropinemia. The thyroid gland was imaged by transverse scanning at the neck; the maximum thickness and the maximum width of the right and left lobe were measured. On the basis of the normal thyroid gland size obtained from normal children, the thyroid gland image of the patients were classified into 4 types: large image, normal image, small image, and no image of the thyroid gland at the neck: no image of the thyroid gland indicated agenesis or ectopia; large thyroid gland image indicated goitorous hypothyroidism. On the other hand, normal or small thyroid gland image probably included mild or transient forms of hypothyroidism, and transient hyperthyrotropinemia; these 2 types required further examination to complete the diagnosis. We concluded that real-time ultrasonography of the thyroid gland was a useful diagnostic imaging technic for patients who revealed elevated serum thyrotropin on neonatal mass-screening.

Adolescent↗
PubMed1973

An automated passive haemagglutination technique suitable for the detection of hepatitis B virus antigen and antibody in blood donors.

A method is described for preparing purified hepatitis B antigen (HB Ag) viral antigen without density gradient centrifugation. A method for sensitizing human group O red cells with this preparation is given, together with the technical details of an automated passive haemagglutination technique suitable for the mass screening of blood donors for HB virus and anti-HB antibody.

Adsorption↗
PubMed1999

Liquid chromatography-mass spectrometry: potential in forensic and clinical toxicology.

A relatively limited number of papers concerning applications of liquid chromatography-mass spectrometry (LC-MS) to forensic or clinical toxicology, or analytical methods directly applicable to these topics have been published so far, but their number have greatly increased in the past two years, probably due to technical improvements and to a decrease in the price of such instruments. After a brief presentation and exemplary applications of the interfaces and/or sources proposed in the past for coupling HPLC to mass spectrometry (direct liquid inlet, moving belt, fast atom bombardment and thermospray interfaces), this paper describes electrospray-type and atmospheric pressure chemical ionisation interfaces and their most recent applications in forensic or clinical toxicology. In a third section, the different LC-MS solutions proposed for typical applications in human toxicology, such as the determination of morphine metabolites, LSD and its metabolites and corticosteroids in blood or urine, are reviewed in detail in order to highlight the strengths and weaknesses of each ionisation device and/or analytical method. The last section envisages the new analytical fields opened up by LC-MS in toxicology, regarding mainly peptides, proteins and large molecules, as well as the possible use of LC-MS as a complement to GC-MS for "general unknown" screenings; it also deals with the perspectives concerning technical improvements in ionisation interfaces/sources or mass spectrometers, as well as in sample preparation and liquid chromatography techniques applied to this type of coupling. Though LC-MS is still a relatively new technique in toxicology, on taking into consideration its success so far and owing to the simplification of instruments and concept handling thanks to user-friendly software, it is the authors' opinion that it will become a major success in analytical toxicology in the next few years.

Atmospheric Pressure↗
PubMed1989

[Basic principles of mass screening of patients with asbestosis].

Complex hygienic, clinical and epidemiologic studies were carried out at 2 enterprises producing asbestos-technical products. It was established that the workers engaged in the production of such products were exposed to relatively low levels of asbestos-containing dust. The course, complications and outcome of asbestos-associated fibrosis were studied in 110 patients. The study revealed that asbestosis was characterized by its slowly progressing development. Asbestosis complications included lung tuberculosis, chronic intersticial pneumonia, and lung cancer. Proceesing from the epidemiologic survey higher risk of malignant neoplasms of the lungs was established in patients with asbestosis in comparison with those exposed to asbestos-associated fibrosis were studied in 110 patients. The study revealed that asbestosis was characterized by its slowly progressing development. Asbestosis complications included lung tuberculosis, chronic intersticial pneumonia, and lung cancer. Processing from the epidemiologic survey higher risk of malignant neoplasms of the lungs was established in patients with asbestosis in comparison with those exposed to asbestos-containing dust but having no occupational disease. The study findings were used for the substantiation of dispensarization principles for patients with asbestosis. The number of follow-up, laboratory and other examinations along with basic curative and preventive measures were pointed out.

Adult↗