ABSTRACT
Disparities relating to postpartum recovery outcomes in different socio-economic and racial ethnic groups are underexplored. We conducted a planned analysis of a large prospective caesarean delivery cohort to explore the relationship between ethnicity, socio-economic status and postpartum recovery. Eligible patients were enrolled and baseline demographic, obstetric and medical history data were collected 18 h and 30 h following delivery. Patients completed postpartum quality of life and recovery measures in person on day 1 (EuroQoL EQ-5D-5L, including global health visual analogue scale; Obstetric Quality of Recovery-10 item score; and pain scores) and by telephone between day 28 and day 32 postpartum (EQ-5D-5L and pain scores). Socio-economic group was determined according to the Index of Multiple Deprivation quintile of each patient's usual place of residence. Data from 1000 patients who underwent caesarean delivery were included. There were more patients of Asian, Black and mixed ethnicity in the more deprived quintiles. Patients of White ethnicities had shorter postpartum duration of hospital stay compared with patients of Asian and Black ethnicities (35 (28-56 [18-513]) h vs. 44 (31-71 [19-465]) h vs. 49 (33-75 [23-189]) h, respectively. In adjusted models at day 30, patients of Asian ethnicity had a significantly greater risk of moderate to severe pain (numerical rating scale ≥ 4) at rest and on movement (odds ratio (95%CI) 2.42 (1.24-4.74) and 2.32 (1.40-3.87)), respectively). There were no differences in readmission rates or incidence of complications between groups. Patients from White ethnic backgrounds experience shorter postpartum duration of stay compared with patients from Asian and Black ethnic groups. Ethnic background impacts pain scores and recovery at day 1 postpartum and following hospital discharge, even after adjusting for socio-economic group. Further work is required to understand the underlying factors driving differences in pain and recovery and to develop strategies to reduce disparities in obstetric patients.
Subject(s)
Ethnicity , Quality of Life , Pregnancy , Female , Humans , Prospective Studies , Cesarean Section , Postpartum Period , Poverty , PainABSTRACT
The case reported is of a 46 year old male who presented with a history of acute on chronic knee pain. The clinical features and investigations suggested a tear of the quadriceps tendon, with pre-existing chronic calcific enthesopathy. The operative findings were of an acute collection of calcific material within the quadriceps tendon. This acute presentation and calcific collection have not previously been reported in the quadriceps tendon.
Subject(s)
Calcinosis/diagnosis , Quadriceps Muscle , Tendinopathy/diagnosis , Calcinosis/diagnostic imaging , Diagnosis, Differential , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Quadriceps Muscle/diagnostic imaging , Radiography , Tendinopathy/diagnostic imaging , Tendon Injuries/diagnosisABSTRACT
Lower oesophageal foreign body meat bolus obstruction is potentially life-threatening. We report a case in a 94-year-old woman in which conservative measures and flexible oesophagoscopy were unsuccessful. Rigid oesophagoscopy was considered technically difficult and so clearance by interventional radiology was attempted. Through the mouth a radiologically guided balloon catheter was introduced. It was passed beyond the bolus to dilate the site of obstruction, before being withdrawn and inflated above the bolus, pushing it into the stomach. Although successful in this case, the technique is previously unreported and so its complication rate is unknown. It is therefore presented only to be considered when other treatments are neither effective nor possible.
Subject(s)
Catheterization/methods , Esophagus , Foreign Bodies/therapy , Aged , Aged, 80 and over , Endoscopy, Gastrointestinal , Female , HumansABSTRACT
Metastatic lesions of the parotid gland are well described in the literature. Metastatic spread to the parotid from renal cell carcinoma is rare. We present the only reported case of facial nerve palsy caused by a metastasis to the parotid from a renal cell carcinoma.
Subject(s)
Carcinoma, Renal Cell/secondary , Facial Paralysis/etiology , Kidney Neoplasms/diagnosis , Parotid Neoplasms/secondary , Carcinoma, Renal Cell/complications , Carcinoma, Renal Cell/diagnosis , Humans , Male , Middle Aged , Parotid Neoplasms/complications , Parotid Neoplasms/diagnosisABSTRACT
We present a rare case of an intra-parenchymal thyroid epidermal cyst presenting with a left recurrent laryngeal nerve palsy. There was a complete recovery of the nerve function following surgical excision of the lesion. Theories of aetio-pathogenesis of the cyst and underlying mechanisms responsible for the nerve paralysis are explored.
Subject(s)
Epidermal Cyst/complications , Thyroid Diseases/complications , Vocal Cord Paralysis/etiology , Biopsy, Needle , Epidermal Cyst/diagnosis , Epidermal Cyst/surgery , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Thyroid Diseases/diagnosis , Thyroid Diseases/surgery , Thyroid Function Tests , Treatment Outcome , Ultrasonography, Doppler , Vocal Cord Paralysis/diagnosis , Vocal Cord Paralysis/surgeryABSTRACT
A case of post-traumatic retropharyngeal haematoma causing airway obstruction in an elderly man on anticoagulant therapy is described. The importance of managing the airway, cervical spine and haemostatic problem with the help of a multidisciplinary team is discussed.
Subject(s)
Accidental Falls , Airway Obstruction/etiology , Cervical Vertebrae/injuries , Head Injuries, Closed/complications , Hematoma/etiology , Pharyngeal Diseases/etiology , Aged , Hematoma/diagnostic imaging , Humans , Male , Pharyngeal Diseases/diagnostic imaging , Radiography , Treatment OutcomeABSTRACT
We report a case of Pott's puffy tumour in a 12-year-old. Owing to the late development of the frontal sinuses, frontal sinus infection in children is rare. When present it can lead to osteomyelitis associated with forehead swelling. Early diagnosis and active treatment prevent progression to life-threatening intracranial spread.
Subject(s)
Edema/etiology , Frontal Sinusitis/complications , Child , Edema/diagnostic imaging , Female , Forehead , Humans , Osteomyelitis/diagnostic imaging , Osteomyelitis/etiology , Tomography, X-Ray ComputedABSTRACT
PURPOSE: We conducted a retrospective study of the distribution of sonographically detected abnormalities in the heels of patients who had a clinical diagnosis of Achilles tendinosis. METHODS: One hundred eighteen symptomatic heels in 73 patients who had a clinical diagnosis of chronic Achilles tendinosis were examined over a 12-month period by the same experienced sonologist. The distribution of altered tendon architecture and features suggesting retrocalcaneal bursitis or Achilles paratendinosis were evaluated. RESULTS: Sonograms of 118 symptomatic heels demonstrated that 96 (81%) had abnormalities confined to the proximal two thirds of the Achilles tendon, 9 (8%) had abnormalities in the distal third alone, and 13 (11%) had abnormalities at both sites. Of the 109 heels with proximal two-third Achilles tendon disease, 99 (91%) had medial tendon involvement; 22 of the 99 showed diffuse tendon changes. Lateral tendon segment changes were seen in 22 (19%) of the 118 symptomatic heels. No lateral tendon segment was involved in isolation. Of the 22 heels with distal third abnormalities, 14 (64%) had sonographic evidence of Achilles paratendinitis, and 13 (59%) had sonographic evidence of Achilles tendinosis. Eighteen of the 22 had sonographic evidence of retrocalcaneal bursitis. In all cases of distal third tendinosis, the deep surface of the tendon was primarily involved. In the heels with both proximal and distal changes, superficial segment involvement of the mid-Achilles tendon was present. CONCLUSIONS: Sonography provides information that helps to accurately diagnose clinical Achilles tendinopathy and may help to determine the biomechanical processes involved in the injury.
Subject(s)
Achilles Tendon/diagnostic imaging , Tendinopathy/diagnostic imaging , Achilles Tendon/injuries , Adult , Aged , Chronic Disease , Female , Heel/diagnostic imaging , Heel/injuries , Humans , Male , Middle Aged , Retrospective Studies , UltrasonographyABSTRACT
OBJECTIVE: To assess the number and distribution of tendon microtears in asymptomatic controls and athletes with chronic Achilles tendinitis or partial thickness tears using high resolution ultrasound. METHODS: The mean number of microtears in three random tendon cross sections were recorded per tendon third in 19 asymptomatic volunteers, 16 athletes with symptomatic chronic Achilles tendinitis, and eight athletes with partial Achilles tendon rupture. RESULTS: Microtears were most numerous in the middle third section of the Achilles tendon. Some 67% of tendons in the control group had no microtears, and 28% showed a single microtear. Only 18% of the athletes with chronic Achilles tendinitis and none of the athletes with partial tendon rupture were without microtears in the middle third of their Achilles tendon. Of the tendons with chronic tendinitis, 13% had more than three microtears per section which increased to 87% in tendons exhibiting partial rupture. CONCLUSIONS: There appears to be an association between microtear formation and Achilles tendon rupture.
Subject(s)
Achilles Tendon/diagnostic imaging , Athletic Injuries/diagnostic imaging , Tendinopathy/diagnostic imaging , Achilles Tendon/injuries , Anatomy, Cross-Sectional , Case-Control Studies , Chronic Disease , Female , Humans , Incidence , Male , Rupture , UltrasonographyABSTRACT
We prospectively analyzed the outcome in 103 consecutive patients undergoing revision hip replacement, dividing the patients into 2 groups according to their age at the time of surgery. There were 45 patients aged 75 years or older and 58 patients aged younger than 75 years. The results of revision hip replacement in terms of pain relief, functional improvement, and patient satisfaction did not differ between the 2 groups. There was a significantly higher death rate among the elderly patients (13.3% versus 1.7%; P = .0202) and a significantly higher rate of dislocation (20% versus 1.7%; P = .0019). We conclude that revision hip replacement is an effective operation in the elderly, but that patient and surgeon must be aware of the risks that such surgery entails.
Subject(s)
Arthroplasty, Replacement, Hip , Adult , Age Factors , Aged , Aged, 80 and over , Humans , Middle Aged , Pain Measurement , Postoperative Complications , Prospective Studies , Prosthesis Design , Prosthesis Failure , Reoperation , Treatment OutcomeABSTRACT
Langerhans' cell histiocytosis is a rare disorder of unknown aetiology in which pathological Langerhans' cells accumulate and destroy local tissue. We report a 38-year-old female who presented with a sudden onset of left sensorineural hearing loss. Magnetic resonance imaging (MRI) revealed a contrast-enhancing lesion in the left mastoid and a second lesion in the hypothalamus. Following left mastoid exploration and biopsy a definitive diagnosis of Langerhans' cell histiocytosis was made and the patient was treated with external beam radiotherapy. Subsequent right femur and right mastoid involvement were successfully treated with steroids and cytotoxic chemotherapy. At one year follow-up the patient had residual left-sided sensorineural hearing loss with normal hearing in the right ear. To our knowledge, Langerhans' cell histiocytosis has not been previously reported as a cause of unilateral sudden onset sensorineural hearing loss. It should be considered in the differential diagnosis of this condition.
Subject(s)
Hearing Loss, Sensorineural/etiology , Histiocytosis, Langerhans-Cell/complications , Adult , Female , Follow-Up Studies , Histiocytosis, Langerhans-Cell/diagnosis , Humans , Magnetic Resonance ImagingABSTRACT
BACKGROUND: Analysis of estrogen receptor (ER) and progesterone receptor (PR) status is an important ancillary test in the evaluation of positive breast fine-needle aspirates. This study compares the detection of ER and PR in breast carcinoma cells suspended in PreservCyt with that achieved with stored ThinPrep slides (TP). METHODS: ER and PR positive mammary tumor cells (cell line ZR-75-1 spiked in PreservCyt by the American Type Culture Collection) were used to evaluate the stability of immunodetection of ER and PR under two conditions: 1) TP slides prepared immediately from PreservCyt and stored air-dried (stored TP) for up to 56 days, and 2) TP prepared from cells suspended in PreservCyt (newly prepared TP) on Days 1, 2, 5, 14, 21, 42, and 56. At each of the time periods, stored TP and newly prepared TP were analyzed for ER and PR using the same immunocytochemical staining protocol. The percentage of positive cells was calculated by counting 1000 cells/TP. RESULTS: Positivity for ER and PR was demonstrated in both stored TP and newly prepared TP on Days 1, 2, 5, 14, 21, 42, and 56. Over the 56-day period, the number of ER positive cells ranged from 41% to 57% in stored TP and from 38% to 58% in newly prepared TP. The number of PR positive cells ranged from 31% to 41% in stored TP and from 26% to 37% in newly prepared TP. Mild, nonspecific cytoplasmic and nuclear staining occurred in all newly prepared TP (PR > ER). CONCLUSIONS: ER and PR antigenicity was preserved in both stored TP and newly prepared TP of mammary tumor cells over a 56-day storage period. This demonstrates that ER and PR status can be evaluated in cytologic material from breast carcinoma using the ThinPrep technique.
Subject(s)
Biopsy, Needle , Breast Neoplasms/chemistry , Cytological Techniques , Preservation, Biological/methods , Receptors, Estrogen/analysis , Receptors, Progesterone/analysis , Breast Neoplasms/pathology , Cell Count , Female , Humans , Immunohistochemistry , Middle Aged , SuspensionsABSTRACT
INTRODUCTION: For cytologic specimens, the vast majority of immunocytochemical studies (ICC) are performed on non-gynecologic specimens for diagnostic purposes, and they can be performed on unstained or previously stained direct smears. Although the ThinPrep processor (TPP) has been approved for the preparation of non-gynecologic specimens, there is scant literature describing the utility of ICC methodology on cytology specimens fixed and processed by this method. MATERIALS AND METHODS: Forty-one fresh specimens were obtained from the surgical gross room and aspirated or scraped to collect cells for thin layer (TL) and direct smears (DS). Specimens included a variety of neoplastic and nonneoplastic samples that were either Papanicolaou (P) stained or unstained (US). One group of US TL slides was subjected to antigen retrieval (AR). Staining was graded semiquantitatively. Each sample acted as its own control. Antibodies (abs) included: CAM5.2, AE1/3, K903, vimentin, MSA, desmin, s-100, HMB45, PSA, PAP, chromogranin, NSE, insulin, synaptophysin, pCEA, mCEA, mCEAD14, LCA, L26, UCHL-1, OPD-4, thyroglobulin, GCDFP, ER/PR, laminin, collagen IV, PLAP, HCG, CD68, HAM56, and MAC387. RESULTS: Semiquantitative staining overall results comparisons: TLP > DSP TLP < DSP TLP = DSP TLUS > DSUS 11/25 (44%) 6/25 (24%) 8/25 (32%) 9/24 (38%) TLUS < DSUS TLUS = DSUS 3/24 (12%) 12/24 (50%) TLP Vs. TLUS TLP > TLUS TLP < TLUS TLP = TLUS 8/41 (20%) 9/41 (22%) 24/41 (58%) There were five false-negative results, 2 with TL and 3 with DS, and 1 false-positive TL. DISCUSSION: Immunocytochemistry performed on the ThinPrep Processor showed equal or greater intensity and distribution of proper staining when compared to direct smears with the following advantages: (1) cleaner background, easier to interpret; (2) less abs required in a smaller area; (3) IPX can be done on Papanicolaou-stained thin layer slides; (4) thin layer slides can be modified for multiple abs tests; (5) additional thin layer slides can be prepared for ICC bases on needs. No significant differences of immunostaining were seen when comparing thin layer Papanicolaou-stained and unstained slides. Antigen retrieval offered no advantage in this study.
Subject(s)
Histological Techniques , Immunohistochemistry/methods , Antibodies/analysis , Biopsy, Needle , Female , Humans , Male , Neoplasms/immunology , Neoplasms/pathologyABSTRACT
We present data from a clinical trial study in which an automated version (Galileo) of a previously described Q-Beta replicase-amplified probe assay (J. S. Shah et al., J. Clin. Microbiol. 33:1435-1441, 1995) was used for the direct detection of Mycobacterium tuberculosis complex in sputum. The assay was designed to target specific regions of 23S rRNA found in M. tuberculosis, Mycobacterium bovis, Mycobacterium africanum, and Mycobacterium microti and had a sensitivity ranging from approximately <10 to 300 CFU. The assay was tested for cross-hybridization by using large numbers (e.g., 10(5)to 10(10) CFU/assay) of 133 other organisms commonly found in respiratory tract samples, including non-M. tuberculosis Mycobacterium spp., other bacteria, fungi, and viruses. All of these competitors tested negative by the assay. Automated assay results for 780 respiratory tract samples (sputum or bronchoalveolar lavage specimens) collected and tested at three trial sites in the United States) were compared with the results of culture and acid-fast microscopy. Aliquots of conventionally digested and decontaminated sputum pellets were heated at 100 degrees C and mechanically disrupted prior to hybridization and background reduction, amplification, and detection in a closed disposable test pack. Pertinent elements of individual patient histories relating to tuberculosis exposure, previous active disease, antituberculosis therapy status, etc., were considered in the resolution of discrepant results for 48 (assay false-positive) samples. Seventy-one of 90 (78.9%) culture-positive samples were positive when tested in the Galileo assay, while 7% of culture-negative samples were assay positive, corresponding to a sensitivity of 79% and a specificity of 93%. Following resolution of discrepant results by chart review, the sensitivity and specificity for the Q-Beta replicase amplification assay with the Galileo analyzer were 84 and 97%, respectively. A total of 69.2% of smear-negative (culture positive) samples were detected by the assay. Ten test packs at a time were automatically processed by the Galileo analyzer without operator intervention following loading of samples. The first result was reported in approximately 3 h, and the last result was available in 6.5 h. To our knowledge, this is the first report of a clinical study with a fully automated amplification probe hybridization assay for the detection of pathogens directly from a clinical specimen.
Subject(s)
Mycobacterium tuberculosis/isolation & purification , Nucleic Acid Amplification Techniques , Q beta Replicase , Tuberculosis/diagnosis , Bronchoalveolar Lavage Fluid/microbiology , Humans , Mycobacterium/isolation & purification , RNA, Ribosomal, 23S/analysis , RNA, Ribosomal, 23S/genetics , Sensitivity and Specificity , Sputum/microbiology , Staining and Labeling , Tuberculosis/microbiology , United StatesABSTRACT
The accuracy of the modified Alvarado score was assessed prospectively in the preoperative diagnosis of acute appendicitis in children. A consecutive series of 118 patients (54 boys, 64 girls) with acute abdominal pain was studied prospectively over a 6 month period. Appendicitis was confirmed in 38 of 43 children undergoing appendicectomy, giving a false-positive appendicectomy rate of 11.6%. No child under active observation was subsequently found to have a perforated appendix. The overall sensitivity of a modified Alvarado score of > or = 7 was 76.3% and its specificity was 78.8%. Current clinical practice is more accurate than the modified Alvarado score in the diagnosis of acute appendicitis in children.
Subject(s)
Appendicitis/diagnosis , Severity of Illness Index , Acute Disease , Adolescent , Child , Child, Preschool , Diagnosis, Differential , Evaluation Studies as Topic , Female , Humans , Male , Prospective Studies , Sensitivity and SpecificityABSTRACT
BACKGROUND: Femoral hernias are rare in children, accounting for fewer than 1 per cent of all paediatric groin hernias. Misdiagnosis is common and a source of complications. There is no consensus on the age and sex distribution or the optimum method of repair. METHODS: A personal experience of four children with femoral hernia is reported together with an institutional review of a further ten hernias encountered during the past 11 years. RESULTS: Peak incidence was between 5 and 10 years of age. Misdiagnosis was common, partly because of the variability in presenting symptoms and signs. In this series, boys were more commonly affected but a literature review indicated a similar sex incidence. CONCLUSION: A femoral hernia should be positively excluded if the operative findings at inguinal exploration are inconsistent with the preoperative signs and in any child with a suspected recurrent inguinal hernia. Excision of the sac and repair of the femoral canal is curative.
Subject(s)
Hernia, Femoral/surgery , Adolescent , Age Distribution , Child , Child, Preschool , Diagnostic Errors , Female , Hernia, Femoral/diagnosis , Humans , Male , RecurrenceABSTRACT
Packing of the nasal cavity following intranasal surgery is still widely practised. The removal of this packing is invariably associated with a significant amount of pain. We designed a prospective randomised case-controlled study to look at the efficacy of 4% lignocaine solution as a potential analgesic in the removal of Merocel nasal packs. Each patient had bilateral packs and acted as his or her own control with one pack being rehydrated with lignocaine and the other with saline. We found that there was a reduction in the level of discomfort experienced on the side rehydrated with lignocaine, although this reduction did not reach significance. We emphasize the importance of rehydration of these packs prior to removal.
Subject(s)
Anesthetics, Local/administration & dosage , Formaldehyde , Hemostatics , Lidocaine/administration & dosage , Nose/surgery , Pain, Postoperative/drug therapy , Polyvinyl Alcohol , Postoperative Complications/prevention & control , Anesthetics, Local/therapeutic use , Case-Control Studies , Female , Humans , Lidocaine/therapeutic use , Male , Pain Measurement , Postoperative Hemorrhage/prevention & control , Prospective Studies , Tampons, SurgicalABSTRACT
We report the results of a study conducted to evaluate the performance of manual Q-Beta replicase-amplified Mycobacterium tuberculosis complex assay compared with that of culture for detecting M. tuberculosis directly from digested sputum pellets. A total of 261 specimens submitted to three tuberculosis testing laboratories were analyzed. Culture and acid-fast bacillus smear results were provided by the tuberculosis testing laboratories. Of these 261 specimens, 34 (13% prevalence rate) were positive for M. tuberculosis by culture. The samples were digested and decontaminated by the testing laboratories by using their standard digestion and decontamination procedures. An aliquot of the digested and decontaminated pellet was sent to GENE-TRAK. The digested and decontaminated pellet was neutralized by washing it with 0.067 M phosphate buffer (pH 6.8), and the bacteria present in the washed pellet were heat inactivated at 100 degrees C for 15 min. The samples were combined with sample processing buffer containing GuSCN and were treated for 6 min in the GENE-TRAK Sample Processing Instrument to release the nucleic acids. The release rRNA was analyzed in a manual Q-Beta replicase assay format which incorporates elements of sandwich hybridization, reversible target capture, and Q-beta replicase signal amplification technologies. In comparison with culture, the overall assay sensitivity and specificity were 97.1 and 96.5%, respectively. The positive predictive value was 80.5%, and the negative predictive value was 99.5%. After analysis of discrepant results, the assay sensitivity and specificity were 97.3 and 97.8, respectively, and the prevalence rate was 14%. The positive predictive value and the negative predictive value were 87.8 and 99.5%, respectively. The Q-Beta replicase assay is rapid sensitive, semiquantitative, and specific for the direct detection of M. tuberculosis from clinical specimens.
Subject(s)
Bacteriological Techniques , Molecular Probe Techniques , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/isolation & purification , Q beta Replicase , Tuberculosis, Pulmonary/diagnosis , Bacteriological Techniques/statistics & numerical data , Evaluation Studies as Topic , False Negative Reactions , False Positive Reactions , Humans , Molecular Probe Techniques/statistics & numerical data , RNA, Ribosomal, 23S/genetics , RNA, Ribosomal, 23S/isolation & purification , Sensitivity and Specificity , Sputum/microbiology , Tuberculosis, Pulmonary/microbiologyABSTRACT
In order to study infections due to Chlamydia trachomatis, we have compared semiquantitative PCR and Q beta replicase-amplified assays for detection of this organism. The PCR assay was directed against the C. trachomatis 16S rRNA gene. Quantitation was accomplished by adding known amounts of a plasmid containing a truncated segment of the 16S rRNA gene target to chlamydia-containing samples and then amplifying with a common primer set. The Q beta replicase assay consisted of reversible target capture of C. trachomatis 16S rRNA, which was followed by amplification of an RNA detector probe in the presence of the enzyme Q beta replicase. In a clinical matrix, the lower limit of detection of both the PCR and Q beta replicase assays was five elementary bodies. The Q beta replicase and PCR assays were quantitative over 10,000- and 1,000-fold ranges of organisms, respectively. Analysis of the effects of endocervical matrix on amplification was accomplished by examining 94 endocervical specimens by each technique. Both assays detected five of six culture-confirmed specimens as well as three culture-negative specimens. PCR inhibitors were detected in 13 specimens. The Q beta replicase assay, in contrast, showed no evidence of sample inhibition. The Q beta replicase and PCR assays should allow quantitative investigation of infections due to C. trachomatis. In addition, because it targets highly labile RNA, the Q beta replicase assay may facilitate investigations into the role of active persisting infection in culture-negative inflammatory conditions.
Subject(s)
Chlamydia Infections/diagnosis , Chlamydia trachomatis/isolation & purification , Polymerase Chain Reaction/methods , Base Sequence , Cervix Uteri/microbiology , Chlamydia Infections/microbiology , Chlamydia trachomatis/genetics , DNA, Ribosomal/genetics , Female , Humans , Molecular Sequence Data , Q beta Replicase , RNA, Ribosomal, 16S/genetics , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
A sensitive, nonisotopic hybridization assay termed "dual capture" is described. The assay rapidly and specifically detects very low levels of target nucleic acids and organisms. The assay is based on the principles of sandwich hybridization, reversible target capture, and Q-Beta replicase amplification. The assay can be completed in less than 4 h, and in the described model format, it detects Chlamydia trachomatis rRNA or rDNA. Up to 96 samples can be analyzed simultaneously. The assay employs two types of probes: a test-specific capture probe, which mediates the cycling of the target probe complex on and off derivatized magnetic beads, and a replicatable RNA detector molecule containing a sequence complementary to and adjacent to the capture probe site on the target. Following reversible target capture, detection of the signal is accomplished by replication of the detector molecule by Q-Beta replicase in the presence of propidium iodide. A specific assay signal can be detected from as few as 1,000 molecules above the background. In a limited study of 94 urogenital samples the assay detected five of the six culture-positive samples and did not detect the C. trachomatis target in 85 of the 88 culture-negative samples.