The comparative diagnostic accuracy of conventional and liquid-based cytology in a colposcopic setting

OBJECTIVE

This study was conducted to compare the performance of liquid-based cytology (LBC) and conventional cytology (CS) in the high prevalence setting of colposcopy clinic.

DESIGN

A split sample of matched ThinPrep (TP) and conventional smear from 563 patients were evaluated blindly. The performance of both techniques was compared with the gold standard of biopsy results or normal colposcopy examination in 441 cases.

SETTING

Colposcopy clinic of an inner city hospital for women and children.

SAMPLE

Five hundred and sixty-three women referred to colposcopy clinic over 14-month period.

METHODS

Cervical smears were taken from 563 women referred for colposcopy. Using the split-sample technique, the material was spread on a conventional (CS) slide and the remaining material rinsed in a PreservCyt solution. A T2000 processor was used to prepare LBC preparations. All women underwent colposcopy/biopsy according to local protocol. Four hundred and forty-one women met the diagnostic standard criteria of the study, which was either a normal colposcopy or histopathology result. Sensitivity, specificity and positive and negative predictive values were calculated for both methods of cytology preparations.

MAIN OUTCOME MEASURES

Matched TP and conventional smears, detection of abnormality, matched biopsies, sensitivity, specificity, and positive and negative predictive values.

RESULTS

Inadequate rates for CS and LBC (TP) were 4.3% and 0.68%, respectively. In 73% of cases, the CS and the LBC preparations showed exact agreement, whereas 77% agreement was seen when comparison was made for amalgamated low grade and high grade abnormalities. Low grade cytological abnormalities accounted for 44% of LBC slides versus 37% in CS slides. High grade cytological abnormalities accounted for 22% of LBC versus 17% seen in CS cases (P < 0.001). LBC showed increased sensitivity in the detection of CIN2 or worse than CS (92% and 83%, respectively) and CS showed greater specificity than LBC (82% and 76%, respectively).

CONCLUSIONS

In high prevalence setting, LBC performed at least as well as CS. The inadequate rate was significantly lower with LBC. The numbers are too small, however, to make confident comments about increased sensitivity and negative predictive value with LBC. Larger studies are required to verify these findings.

Particle size characterization and the indoor-to-outdoor relationship of atmospheric aerosols in Helsinki

OBJECTIVES

The influence of traffic and meteorological conditions on aerosol characteristics outdoors, the relationship between indoor and outdoor aerosol particles, and the pollutant transport indoors by means of a mechanical ventilation system were studied.

METHODS

Indoor and outdoor concentrations of fine-particle numbers were measured during the summer (15 May--30 June 2000) in one office located in the basement of a building in Helsinki, Finland. The total number concentration was measured with a condensation particle counter, and the particle number size distribution (7-600 nm) was measured with a differential mobility particle sizer. The size distribution (0.3-25 microm) of the indoor particle numbers was periodically measured with a laser particle counter.

RESULTS

Meteorological conditions, especially wind direction, had the greatest effect on the total number concentration and the size distribution of aerosol particles outdoors. The outdoor number concentration of ultrafine particles (diameter <100 nm) was strongly dependent on traffic density. The temporal variations in the indoor number concentration of ultrafine and fine particles (7-600 nm) closely followed the corresponding temporal variations outdoors. The building ventilation system was the main means of transporting aerosols indoors. The mean penetration factor was 0.41 (SD 0.11) for the nucleation mode (7-25 nm), 0.74 (SD 0.09) for the Aitken mode (25-100 nm), and 0.87 (SD 0.06) for the accumulation mode (100-600 nm).

CONCLUSIONS

The ultrafine particles were bimodal with a nucleation mode (particle diameter <25 nm) and an Aitken mode (25 nm <particle diameter <100 nm). An accumulation mode was observed with a particle diameter larger than 100 nm. The patterns of fine-particulate air pollution inside an office can be largely estimated on the basis of the outdoor aerosol characterization and the mechanical ventilation system.

Particle concentration profile in a vertical displacement flow: a study in an industrial hall

The effect of displacement flow on the distribution of aerosol concentration was investigated in an industrial hall. According to the displacement ventilation principle, vertical upflow is accomplished by introducing fresh air, cooler than room air, into the occupied zone near floor level. The fresh air is introduced from low-velocity devices and heated by warm processes. This technique allows warm air contaminants to rise to the ceiling, and the rising plume is then exhausted close to the ceiling. This study presents the results of a field study conducted in an industrial environment. The aerosol properties and behavior, especially the vertical gradients, are characterized in a displacement flow field. The results indicate that the fine particles, less than 1 microm in diameter, are transported away from the breathing zone by the ventilation process. However, the air quality is significantly influenced by the emission source, and therefore the number concentration of fine and ultrafine (smaller than 0.1 microm in diameter) aerosol particles in the breathing zone was clearly elevated compared to that of the incoming clean air. The vertical gradients displayed clear size dependence; the strongest gradients were found for particles between 0.003 and 0.015 microm in diameter.

Questionnaire on practices and priorities in neonatal care in Ireland

As part of a process of audit of neonatal practice, a questionnaire on clinical practice and priorities which need to be addressed was sent to all consultant neonatologists, and to a consultant paediatrician in all other units caring for newborn infants, in the Republic of Ireland. The response rate was 88% (22 out of 25 replied). Thirteen respondents specified greater than 24 weeks and/or greater than 500 grams as the criteria at which infants were resuscitated. Eleven routinely intubated very premature infants. Seven treated any infant intubated for respiratory distress syndrome with surfactant, and seven sometimes used prophylactic surfactant. Poor perfusion or low blood pressure was the most common criterion for volume expansion during the first hour, using albumen (15 of 22), fresh frozen plasma (10), whole blood (9), normal saline (20 and haemacell (1). Most (18 of 22) used steroids for established bronchopulmonary dysplasia. Oral feeds were generally begun "as soon as possible". Persistent foetal circulation was treated with various vasodilators, tolazoline (14 of 22), magnesium sulphate (8) and nitric oxide (4). The main local priorities noted are the need for more neonatally trained nursing and / or medical staff. Almost all respondents noted the need for a national neonatal transport system. While this summary reveals a considerable variation in clinical practice this variation reflects the lack of evidence on which to base clinical decision making. Where evidence exists from clinical trials considerable uniformity exists in clinical decision making and practice. This study highlights the need for continued audit of clinical practice and the essential role clinical research plays in informing decision making in practice.

A profile of tumor markers in the population of Kuwait

The tumour markers CEA, AFP, CA 125 and CA 199 were analyzed in a group of apparently healthy subjects in Kuwait. The sample (n = 394) included both genders in the population with a mean age of 38 (S.d. 12.0) years. The distribution of CEA levels values was significant different (Mann-Whitney U test) between Kuwaiti and non-Kuwaiti. The distribution of AFP levels was found to be the same in all groups. The distribution of CA 125 levels was significantly higher in females than in males, both in Kuwaiti and non-Kuwaiti. The distribution of CA 19-9 values was found to be significantly higher in the Kuwaiti female group when compared to the males. The upper reference level was defined as the 95 percentile of the normal values in each group. In the total population the reference level of AFP was 5.6 micrograms/l and of CA 19.9 43 kU/l. The reference level of CA 125 was 16 U/l in males and 24 kU/l in females, respectively. The CEA reference level in Kuwaitis was 6.9 micrograms/l and in non-Kuwaitis 4.4 micrograms/l. The results indicated the importance of determining the reference levels of tumour markers for each individual laboratory. It was also emphasized that care should be taken on the impact of 95 percentiles of normal and benign disease groups.

Psychometric characteristics and clinical usefulness of physical performance tests in patients with low back pain

STUDY DESIGN

The psychometric properties and clinical use of a battery of physical performance measures were tested on 44 patients with low back pain and 48 healthy, pain-free control subjects.

OBJECTIVES

Reliability, validity, and clinical use of nine physical performance measures were evaluated.

SUMMARY OF BACKGROUND DATA

Although physical performance measures have potential use in evaluation, treatment planning, and determination of treatment outcome, there is sparse systematic investigation of their reliability, validity, and clinical use.

METHODS

Forty-four subjects with low back pain and 48 healthy pain-free subjects participated. The following physical performance measures were tested: distance walked in 5 minutes; 50-foot walk at fastest speed; 50-foot walk at preferred speed; 5 repetitions of a sit-to-stand task; 10 repetitions of a repeated trunk flexion task; timed up-and-go task; unloaded forward reach task; loaded forward reach task; and Sorensen fatigue test. Subjects were assessed twice on 2 days.

RESULTS

All measures had excellent intertester reliability (intraclass correlation coefficient [ICC]1,1 > 0.95). Test-retest (within session) reliability was adequate for all measures (ICC1,1 > 0.83) except repeated trunk flexion (ICC1,1 > 0.45) in the low back pain group. Test-retest (day-to-day) reliability ranged between 0.59 and 0.88 in the low back pain group and between 0.46 and 0.76 in the control group. Day-to-day reliability improved when the averages of two trials of repeated trunk flexion and sit-to-stand were used (0.76-0.91 low back pain group and 0.62-0.89 control group). Results of a multivariate analysis of variance showed a significant effect of group (F10,65 = 3.52, P = 0.001). Results of univariate analyses showed significant group differences on all measures except the 50-foot walk at preferred speed and unloaded forward reach. Self-report of disability was moderately correlated with the performance tasks (r = 0.400 to -0.603).

CONCLUSIONS

The results provide support for the use of these physical performance measures as a complement to patient self-report.