Engineering and manufacturing of ITER first mirror mock-ups.

Most of the ITER optical diagnostics aiming at viewing and monitoring plasma facing components will use in-vessel metallic mirrors. These mirrors will be exposed to a severe plasma environment and lead to an important tradeoff on their design and manufacturing. As a consequence, investigations are carried out on diagnostic mirrors toward the development of optimal and reliable solutions. The goals are to assess the manufacturing feasibility of the mirror coatings, evaluate the manufacturing capability and associated performances for the mirrors cooling and polishing, and finally determine the costs and delivery time of the first prototypes with a diameter of 200 and 500 mm. Three kinds of ITER candidate mock-ups are being designed and manufactured: rhodium films on stainless steel substrate, molybdenum on TZM substrate, and silver films on stainless steel substrate. The status of the project is presented in this paper.

Multicenter evaluation of AMPLICOR and automated COBAS AMPLICOR CT/NG tests for Neisseria gonorrhoeae.

The fully automated COBAS AMPLICOR CT/NG and semiautomated AMPLICOR CT/NG tests were evaluated in a multicenter trial for their ability to detect Neisseria gonorrhoeae infections. Test performance compared to that of culturing was evaluated for 2,192 matched endocervical swab and urine specimens obtained from women and for 1, 981 matched urethral swab and urine specimens obtained from men. Culture-negative, PCR-positive specimens that tested positive in a confirmatory PCR test for an alternative target sequence within the N. gonorrhoeae 16S rRNA gene were considered to be true positives. The overall prevalences of gonorrhea were 6.6% in women and 20.1% in men. The COBAS AMPLICOR and AMPLICOR formats yielded concordant results for 98.8% of the specimens and exhibited virtually identical sensitivities and specificities. The results that follow are for the COBAS AMPLICOR format. With the infected patient as the reference standard, the resolved sensitivities of PCR were 92.4% for endocervical swab specimens and 64.8% for female urine specimens. There were no significant differences in these rates between women with and without symptoms. Among symptomatic men, COBAS AMPLICOR sensitivities were 94.1% for urine and 98.1% for urethral swabs; for asymptomatic men, the results were 42.3 and 73.1%, respectively. In comparison, the sensitivities of culturing were 84.8% for endocervical specimens, 92.7% for symptomatic male urethral specimens, and only 46.2% for urethral specimens obtained from asymptomatic men. When PCR results were analyzed as if only a single test had been performed on a single specimen type, the resolved sensitivity was always higher. The resolved specificities of PCR were 99.5% for endocervical swab specimens, 99.8% for female urine specimens, 98.9% for male urethral swab specimens, and 99.9% for male urine specimens. The internal control revealed that 2.1% of specimens were inhibitory when initially tested. Nevertheless, valid results were obtained for 99.2% of specimens because 60.0% of the inhibitory specimens were not inhibitory when a second aliquot was tested. The COBAS AMPLICOR CT/NG test for N. gonorrhoeae exhibited high sensitivity and specificity with urethral swab and urine specimens from men and endocervical swab specimens from women and thus is well suited for diagnosing and screening for N. gonorrhoeae infection.

Molecular characterization of Haemophilus ducreyi strains from Jackson, Mississippi, and New Orleans, Louisiana.

Chancroid, a sexually transmitted disease caused by Haemophilus ducreyi, is one of the most common genital ulcer diseases in developing countries. In the United States, while less common, the disease has been associated with outbreaks in inner cities, particularly among persons who engage in sex for drugs or money. Two outbreaks of chancroid were recently studied in the United States, one in New Orleans (from 1990 to 1992) and one in Jackson, Mississippi (from 1994 to 1995). By use of ribotyping, plasmid content, and antibiotic susceptibility, the chancroid cases in New Orleans were found to be due to a limited number of strains, consistent with a limited introduction of H. ducreyi into this community. The H. ducreyi isolates from New Orleans and Jackson had different ribotype patterns, suggesting that the two outbreaks were probably not linked.

Alterations in sample preparation increase sensitivity of PCR assay for diagnosis of chancroid.

A PCR assay for the detection of Haemophilus ducreyi in clinical specimens taken from genital ulcers was developed. Although H. ducreyi, when present in such specimens, could be detected by PCR, the sensitivity of the assay was reduced by the presence of Taq polymerase inhibitors in the specimen. The sensitivity of the PCR assay was improved by the use of detergents in preparing nuclei acids from clinical specimens and by the inclusion of a dialysis step prior to amplification. In addition, sodium phosphate included in the transport medium was found to be an inhibitor of the Taq polymerase.

Development of a polymerase chain reaction assay for the detection of Haemophilus ducreyi.

BACKGROUND AND OBJECTIVES: Haemophilus ducreyi, the causative agent of chancroid is a fastidious organism difficult to culture and identify. Consequently, culture is an insensitive method for diagnosis. The polymerase chain reaction (PCR) offers a sensitive and specific nonculture method for the detection of bacterial pathogens. STUDY DESIGN: A polymerase chain reaction (PCR) assay was developed to detect the presence of Haemophilus ducreyi. A pair of primers was selected from sequences of an anonymous fragment of DNA cloned from H. ducreyi. The primers were tested in amplification reactions with both purified DNA and lysed organisms for their ability to detect H. ducreyi, and with DNA from a variety of different bacteria for their specificity. The utility of the primers for the detection of H. ducreyi in samples taken from genital ulcers was also tested and compared with culture. RESULTS: PCR was positive for 62% of the specimens that were culture-positive, however, PCR was also positive for 49% of the culture-negative specimens. Comparison of specimens that were dark field positive for T. pallidum and PCR-positive with those that were culture-positive for herpes simplex virus and PCR positive suggested that PCR was giving true and not random positive results. Additional studies demonstrated that the failure of PCR to detect H. ducreyi in all of the culture-positive specimens probably resulted from inhibitors of the Taq DNA polymerase that were present in the nucleic acids extracted from the clinical specimen. CONCLUSION: PCR should be a useful method for the detection of H. ducreyi in genital lesions, especially where culture sensitivity is poor. However, the presence of unidentified Taq polymerase inhibitors in some ulcers specimens require the development of improved methods for specimen handling.

Comparison of the in vitro activities of various parenteral and oral antimicrobial agents against endemic Haemophilus ducreyi.

The in vitro susceptibilities to various antimicrobial agents of 100 strains of beta-lactamase-producing Haemophilus ducreyi recently isolated from patients in New Orleans, La., were determined by an agar dilution method. All strains were highly susceptible to ceftizoxime, ceftriaxone, ceftazidime, azithromycin, erythromycin, ciprofloxacin, and sparfloxacin. beta-Lactam-beta-lactamase inhibitor combinations were less active, but all strains were susceptible to them. Doxycycline exhibited the poorest activity, and the rate of resistance to doxycycline varied depending on the time after inoculation that the MIC was determined.

MR of slow CSF flow in the spine.

PURPOSE: To evaluate a slow-flow MR sequence in normal CSF flow and in CSF flow disturbance in cases of spinal stenosis. METHOD: The method was tested for flow sensitivity and applied to 67 sites of spinal canal compromise. RESULTS: Phantom studies show that flow can be depicted at a velocity of 0.5-1 mm/sec. On clinical images, stagnant CSF is black, flowing CSF is bright. Typically, in high-grade (90%-100%) stenosis, CSF above and below the site of spinal canal compromise (SCC) is black. With intermediate stenosis (50%-89%), CSF above the SCC remains white but becomes black distal to the SCC. Low-grade stenosis shows only localized flow disturbances. CONCLUSION: This easy-to-use sequence can solidify the MR diagnosis of high-grade stenosis when a distinct flow pattern is recognized. Flow patterns for intermediate and low-grade stenosis are less reliable.

Comparison of different medium bases for the semiquantitative isolation of anaerobes from vaginal secretions.

Two studies were performed to determine the best medium for the isolation of anaerobes from vaginal secretions. In the first, three different medium bases (brucella, Centers for Disease Control [CDC], and Schaedler) were compared semiquantitatively for ability to support the growth of gram-negative anaerobes from vaginal fluid. Media were supplemented with laked sheep blood, kanamycin, and vancomycin. The brucella base agar formulation supported the growth of anaerobic gram-negative bacilli better than either the CDC or Schaedler base agar formulation. In a second study, nonselective brucella and CDC base sheep blood agar were compared for ability to support the growth of anaerobic gram-positive cocci. Anaerobic gram-positive cocci grew in higher concentrations on CDC base agar than on brucella base agar. On the basis of these observations, we recommend that a CDC base sheep blood agar be used for the nonselective plate and a brucella base plate supplemented with laked sheep blood, kanamycin, and vancomycin be used for isolation of gram-negative bacilli in studies of the anaerobic flora of the female genital tract.

[Grisel's syndrome. Description of a case of spontaneous subluxation of the atlas]. / Sindrome di Grisel. Descrizione di un caso di sublussazione spontanea dell'atlante.

Grisel's syndrome is an atlanto-axial dislocation affecting children between 6 and 12 years. The outstanding symptom is a spontaneously arising torticollis. The most likely etiology seems to be an inflammation of the retropharyngeal space caused by upper respiratory tract infections or by adenotonsillectomy. Some A.A. consider Grisel' syndrome clinical features strictly due to predisposing conditions. The anamnesis and clinical signs are important clues to diagnosis. The A.A. report a case of an apparently spontaneous torticollis occurred few days after adenotonsillectomy in a 7 years old girl.

Abdominal abscess drainage under radiologic guidance: causes of failure.

The results of percutaneous drainage of abdominal abscesses in 136 patients are analyzed, revealing a failure rate of 23% (31 patients). The mortality rate was 1.4% (two patients); the rate of serious complications was 5% (seven patients). Failure rate was lowest in critically ill patients having palliative drainage only (12%), emphasizing the importance of immediate drainage to stabilize such patients. The low mortality rate is also attributed to prompt palliative drainage. Technical errors were most commonly responsible for failure of procedures (14%), especially failure to recognize and respond to loculation or subseptation, premature withdrawal of drains (12 patients), and inappropriate approach to the abscess (nine patients). Assignment of patients to a clinical interventional radiology service for the duration of this treatment may greatly facilitate management.

Cerebral venous angiomas imaged by MR.

The diagnostic efficacy of magnetic resonance (MR) in the evaluation of cerebral venous angioma was studied. The results of MR and computed tomography (CT) were compared in six cerebral venous angiomas in five patients. MR alone was diagnostically successful in only three of six cases. Venous angiomas appeared as tubular structures of extremely low signal intensity on MR images. Although CT was highly sensitive (100%) in detecting lesions, CT was diagnostically specific in only four of the six cases. Angiography was the only modality able to unquestionably detect all six lesions. By varying the MR pulse sequence, we greatly affected the ability of MR to demonstrate lesions. In the cases where MR helped define the abnormality, T2-weighted MR images were able to clearly demonstrate lesions in five of the six cases whereas T1-weighted images helped detect an abnormality in only two cases. Although MR shows great promise in the evaluation of central nervous system abnormalities, CT remains the best imaging modality for detecting venous angiomas. When CT is not conclusive, angiography can be performed for a definitive diagnosis.