Comparison of a polymer conjugate-enhanced enzyme immunoassay to ligase chain reaction for diagnosis of Chlamydia trachomatis in endocervical swabs.

Two endocervical swabs from each of 1,123 women were collected into manufacturer-supplied transport tubes and tested for Chlamydia trachomatis by a polymer conjugate-enhanced (PCE) enzyme immunoassay (EIA) (IDEIA PCE Chlamydia; DAKO) and a ligase chain reaction assay (LCx Chlamydia; Abbott). After confirmation by the EIA blocking test, the sensitivity of the IDEIA PCE remained at 91.8% and the specificity increased from 98.2 to 99.8% compared to LCx.

Pooling cervical swabs and testing by ligase chain reaction are accurate and cost-saving strategies for diagnosis of Chlamydia trachomatis.

Specimen pooling to achieve efficiency when testing urine specimens for Chlamydia trachomatis nucleic acids has been suggested. We pooled endocervical swabs from 1,288 women and also tested individual swabs by ligase chain reaction (LCR). Out of 53 positive specimens, pools of 4 or 8 specimens missed two positives, providing 96.2% accuracy compared to individual test results. Dilution and positive-control spiking experiments showed that negative specimens with inhibitors of LCR in the pool reduced the signal. Conversely, two extra positives, detected only through pooling, were negative by individual testing but became positive after storage, suggesting that fresh positive specimens with labile inhibitors may be positive in a pool because of dilution of inhibitors. For this population of women with a 4% prevalence of C. trachomatis infection, substantial savings in cost of reagents (55 to 63%) and technologist time (50 to 63%) made pooling strategies a desirable alternative to individual testing.

The impact on accuracy and cost of ligase chain reaction testing by pooling urine specimens for the diagnosis of Chlamydia trachomatis infections.

BACKGROUND AND OBJECTIVES: Nucleic acid amplification testing is the most accurate approach to diagnosing Chlamydia trachomatis infections. Our objective was to compare the accuracy and cost savings of pooling urines as opposed to individual testing. STUDY DESIGN: Strategies of pooling urine specimens into groups of four (4x pool) or eight (8x pool) followed by testing the positive pools individually were compared to individual specimen testing to determine if significant cost savingS could be realized without compromising the sensitivity and specificity of the LCx C. trachomatis Assay (Abbott Laboratories, Abbott Park, Chicago, IL) performed in a busy private medical laboratory. RESULTS: A total of 1,220 patient urine samples, 1,187 male (97%) and 33 female (3%), were tested using the normal LCx specimen to cutoff ratio (S/CO) of 1.0 and a decreased S/CO value of 0.2. Individual testing identified 98.2% (109/111) of positive urines. The 4x pooling maneuver identified 92.8% (103/111) of positive patients with the regular cutoff and 96.4% (107/111) when the cutoff was decreased. These values were 95.9% (47/49) and 97.9% (48/49), respectively, when eight urines were pooled. Both pooling and individual testing strategies identified all the negative samples accurately. Cost savings of pooling were calculated to be 44.5% for pools of four and 37.5% for pools of eight, applying the lowered cutoff. CONCLUSIONS: Pooling urine specimens for testing with the C. trachomatis LCx system is a simple, accurate, and cost-saving approach that can significantly reduce the cost of amplified nucleic acid testing with minimal sacrifice of testing accuracy.

The radiosensitivity of human fibroblast cell lines correlates with residual levels of DNA double-strand breaks.

PURPOSE: To study the correlation of residual DNA double-strand breakage after irradiation and cellular radiosensitivity in cells showing marked differences in radiosensitivity. MATERIALS AND METHODS: The levels of DNA double-strand breaks remaining at 4 h after irradiation were measured by graded-voltage gel electrophoresis in fibroblast cell strains derived from seven individuals either with normal radiosensitivity (n = 2), or with genetic abnormalities known to show increased (two ataxia telangiectasia, one scid) or possibly decreased (two Li-Fraumeni family members) sensitivity. RESULTS: The slope of the dose-response curve for DNA breaks remaining unrepaired at 4 h showed a highly significant correlation with cellular radiosensitivity characterized by SF2, alpha, or D (r > or = 0.91, P < 0.001). Hence, this measure of genotoxic damage was predictive of radiation sensitivity for cells affected by a variety of mutations in different damage signalling/repair components. DISCUSSION: This correlation confirms another published study and extends it to cell lines with other genetic defects. The technique may be useful in the development of rapid assays to predict the sensitivity of normal tissues in patients receiving radiotherapy.

Ultrasound detection of vault haematoma following vaginal hysterectomy.

OBJECTIVE: To assess whether ultrasound detection of vault haematoma can be used as a predictor of post-operative morbidity following vaginal hysterectomy. DESIGN: Prospective observational study of consecutive cases of vaginal hysterectomy performed between 1991 and 1994. SAMPLE: Two hundred and twenty-three women having undergone vaginal hysterectomy. METHODS: All women had transvaginal ultrasound examination by an independent observer on the third post-operative day. Routine observations and clinical assessments were made by established management protocol, by staff blinded to the ultrasound findings. MAIN OUTCOME MEASURES: Febrile morbidity; haemoglobin drop; need for blood transfusion; length of stay in hospital; re-admission rate and length of stay. RESULTS: Of the 223 scanned women, 55 (25%) had a vault haematoma. This group was compared with the 168 women with no haematoma. Significant increases in febrile morbidity (31% vs 7%), post-operative haemoglobin drop (2.5 g/dL vs 1.6 g/dL), need for blood transfusion (14.5% vs 1.2%), representation to hospital (25.5% vs 5.4%) and length of hospital stay (8.87 days vs 6.25 days) were seen in the haematoma group. CONCLUSION: Ultrasound detection of vault haematoma following vaginal hysterectomy is a common finding associated with increased febrile morbidity, need for blood transfusion, longer hospital stay and higher re-admission rate. In view of increasing demand for early discharge, driven by purchasers and patients, post-operative ultrasound identifies a high risk population and is both convenient and noninvasive. To further reduce morbidity, it also offers the opportunity to perform a controlled trial of prophylactic antibiotics in this identified subset.

Cellular radiosensitivity in human severe-combined-immunodeficiency (SCID) syndromes.

PURPOSE: The aim of the work was to establish to what extent a variety of human severe-combined-immunodeficiency (SCID) disorders are associated with in vitro cellular hypersensitivity to ionizing radiation. MATERIALS AND METHODS: A study was made of fibroblast strains established from individuals with adenosine deaminase deficiency, T(-)B(-) SCID, Omenn's syndrome and a SCID heterozygote. For comparison, an assessment was also made of the radiosensitivity of a series of fibroblast strains derived from: normal donors, a patients with ataxia-telangiectasia (A-T) and an A-T heterozygote. Radiosensitivity was determined using a clonogenic assay following both high (HDR) and low (LDR) dose-rate irradiation. RESULTS: Following HDR irradiation, the fibroblast strains derived from the different human SCID disorders displayed a wide range of radiosensitivity: the adenosine deaminase deficiency cells were similar in radiosensitivity to normal fibroblasts, T(-)B(-) cells were as hypersensitive to radiation as A-T cells and the Omenn's syndrome cells showed intermediate radiosensitivity. However, whereas all four normal cell strains studied showed significant LDR sparing, none of the SCID fibroblasts did. CONCLUSIONS: These data indicate that human SCID is variable in terms of radiosensitivity depending on the particular defect. In addition, the lack of LDR sparing of radiation-induced damage suggests the involvement of some form(s) of DNA repair defect in all the human SCID syndromes.

Fibroblasts from Li-Fraumeni patients are resistant to low dose-rate irradiation.

A group of adult skin fibroblast cultures from four individuals representing Li-Fraumeni families with different mutations in the p53 gene were found to be resistant to low dose-rate (0.011 Gy per min) 60Co radiation when compared with a control group of four cultures from normal individuals. The Li-Fraumeni fibroblasts, which could not be distinguished from controls after high dose rate (1.07 Gy per min) irradiation, were shown to be heterozygous (+/mut) at the p53 locus at the time of irradiation.

Serum tumour markers in carcinoma of the uterine cervix and outcome following radiotherapy.

A study was made of the prognostic value of measurements of pretreatment serum marker levels in patients with carcinoma of the uterine cervix undergoing radiotherapy. The markers studied were carcinoma antigen 125 (CA125), squamous cell carcinoma antigen (SCC) and tissue polypeptide antigen (TPA). The levels of all three markers increased with disease stage. In a univariate analysis stratifying patients according to either median values or cut-off levels representing the top of the normal range, pretreatment levels predicted patient survival (follow-up times 1-4 years). In a multivariate analysis, disease stage was the most important prognostic variable and, after allowing for stage, only CA125 was a significant independent predictor of treatment outcome. These data suggest that, in carcinoma of the cervix treated with radiotherapy, pretreatment measurements of CA125, but not SCC and TPA, may have a role to play in defining prognosis.

PCR and direct fluorescent-antibody staining confirm Chlamydia trachomatis antigens in swabs and urine below the detection threshold of Chlamydiazyme enzyme immunoassay.

In order to test the hypothesis that specimens blocking with a neutralizing reagent below the cutoff of the Chlamydiazyme enzyme immunoassay represent infected patients, we used direct fluorescent-antibody staining for elementary bodies (EBs) and PCR to confirm results for cervical swabs collected from 55,963 women and urethral swabs or first-void urine (FVU) samples collected from 5,781 men attending physicians' offices in the Toronto, Canada, area. Within a grey zone arbitrarily selected to represent values up to 40% below the positive threshold of the test run, 134 cervical swabs, 44 urethral swabs, and 39 FVU specimens exhibited a blocking response ( > 50% reduction in signal). Three or more EBs were observed in each of 98 cervical swabs (73.1%), 38 urethral swabs (86.4%), and 21 FVU specimens (53.8%). Of the 36 cervical swabs with fewer than three EBs, 33 were PCR positive; the positive PCR results for male specimens were 6 of 6 urethral swabs and 17 of 18 FVU samples. Application of the blocking test to specimens negative in the Chlamydiazyme enzyme immunoassay but having optical densities within 40% of the cutoff added 14.2% (217 of 1,531 specimens) more positive results to the survey. A total of 213 of 217 samples (98.2%) were reconfirmed as having EBs or DNA.

Non-surgical treatment of cervical carcinoma.

Since the discovery of radium in 1898, radiotherapy has been used in the treatment of cervical cancer, and it remains the mainstay of treatment today. Chemotherapy is in its infancy and has as yet been unable to improve long-term survival, despite encouraging response.