The application of subset correspondence analysis to address the problem of missing data in a study on asthma severity in childhood.

Non-response in cross-sectional data is not uncommon and requires careful handling during the analysis stage so as not to bias results. In this paper, we illustrate how subset correspondence analysis can be applied in order to manage the non-response while at the same time retaining all observed data. This variant of correspondence analysis was applied to a set of epidemiological data in which relationships between numerous environmental, genetic, behavioural and socio-economic factors and their association with asthma severity in children were explored. The application of subset correspondence analysis revealed interesting associations between the measured variables that otherwise may not have been exposed. Many of the associations found confirm established theories found in literature regarding factors that exacerbate childhood asthma. Moderate to severe asthma was found to be associated with needing neonatal care, male children, 8- to 9-year olds, exposure to tobacco smoke in vehicles and living in areas that suffer from extreme air pollution. Associations were found between mild persistent asthma and low birthweight, and being exposed to smoke in the home and living in a home with up to four people. The classification of probable asthma was associated with a group of variables that indicate low socio-economic status.

Comparison of the effect of heparin and aspirin versus aspirin alone on transient myocardial ischemia and in-hospital prognosis in patients with unstable angina.

OBJECTIVES: This study compared the effects of heparin and aspirin versus aspirin alone on transient myocardial ischemia and in-hospital prognosis in patients with unstable angina. BACKGROUND: Transient myocardial ischemia occurring in patients with unstable angina is associated with an adverse prognosis. Heparin and aspirin are two drugs used frequently in the treatment of this condition, but the effect of combination therapy versus aspirin alone on transient myocardial ischemia is unknown. METHODS: Two hundred eighty-five consecutive patients with unstable angina were randomized to receive either intravenous heparin plus oral aspirin (150 mg once daily) (Group H + A) or aspirin alone (Group A). Patients also received a beta-adrenergic blocking agent, diltiazem and intravenous nitrates. ST segment monitoring was performed for the 1st 48 h of treatment. Patients were followed up for the duration of their in-hospital stay. RESULTS: One hundred fifty-four patients (30 women, mean [+/- SEM] age 58.3 +/- 0.8 years) received heparin and aspirin (Group H + A), and 131 patients (26 women, mean age 60.6 +/- 0.8 years) received aspirin only (Group A). ST segment monitoring (11,622 h) yielded 244 episodes of transient myocardial ischemia of a total duration of 7,819 min. There were no significant differences between the two treatment arms in the number of patients with transient myocardial ischemia (27 [18%] in Group H + A vs. 31 [24%] in Group A), number of episodes (96 in Group H + A vs. 148 in Group A) or total duration of transient myocardial ischemia (2,911 min in Group H + A vs. 4,908 min in Group A). The incidence of in-hospital myocardial infarction or death was significantly higher in patients with transient myocardial ischemia (53% vs. 22%, p < 0.0001). Five of the six deaths occurred in patients with transient myocardial ischemia. Event-free survival from myocardial infarction or death was similar in both treatment groups. Preadmission therapy with aspirin was associated with a lower in-hospital infarction rate (19% vs. 34%, p = 0.01). CONCLUSIONS: The presence of transient myocardial ischemia in patients with unstable angina is associated with a significantly higher incidence of myocardial infarction or death in hospital. Combined therapy with heparin and aspirin compared with aspirin alone makes no difference in the development of these events, nor does it reduce the development of transient myocardial ischemia.

High rates of Chlamydia trachomatis infections in young Papua New Guinean infants.

OBJECTIVE: Determine the importance of Chlamydia trachomatis in the etiology of severe infection in young Papua New Guinean infants. METHODS: Between March, 1991, and April, 1993, children <3 months old were recruited as outpatients at Goroka Base Hospital, Papua New Guinea, as part of a multicenter study in four developing countries. Children with predefined inclusion criteria were enrolled. C. trachomatis was identified by direct fluorescent antibody staining in nasopharyngeal aspirates (NPAs) collected from children with and without signs of severe disease and eye swabs from children with and without conjunctivitis. Two to three radiologists read chest radiographs without knowledge of clinical and laboratory findings. RESULTS: Of 3280 outpatients seen 2168 enrolled, 955 NPAs were tested for C. trachomatis and 549 chest radiographs were read. Of 210 eye swabs from children with conjunctivitis 57% were positive for C. trachomatis compared with 8% from 167 children with no conjunctivitis. The prevalence of C. trachomatis in NPAs was 9% in asymptomatic children and 18 and 33% in children with nonsevere or severe pneumonia, respectively. C. trachomatis in NPAs was strongly associated with clinically severe pneumonia [odds ratio (OR), 2.91], reduced arterial oxygen saturation (OR 2.58) and radiographic evidence of pneumonia (OR 5.84) and was also associated with pneumococcal bacteremia (OR 3.48). CONCLUSIONS: In Papua New Guinea Chlamydia must be considered as a cause when treating pneumonia in infants, and effective treatment and prevention of sexually transmitted diseases are urgently needed for a number of reasons, including the need to curb high rates of chlamydial infection in women and infants.

Early continuous ST segment monitoring in unstable angina: prognostic value additional to the clinical characteristics and the admission electrocardiogram.

BACKGROUND AND OBJECTIVE: In unstable angina, clinical characteristics, resting electrocardiography, and early continuous ST segment monitoring have been individually reported to identify subgroups at increased risk of adverse outcome. It is not known, however, whether continuous ST monitoring provides additional prognostic information in such a setting. DESIGN: Observational study of 212 patients with unstable angina without evidence of acute myocardial infarction admitted to district general hospitals, who had participated in a randomised study comparing heparin and aspirin treatment versus aspirin alone. METHODS: Clinical variables and a 12 lead electrocardiogram (ECG) were recorded at admission, and treatment was standardised to include aspirin, atenolol, diltiazem, and intravenous glyceryl trinitrate, in addition to intravenous heparin (randomised treatment). Continuous ST segment monitoring was performed for 48 h and all inhospital adverse events were recorded. RESULTS: The admission ECG was normal in 61 patients (29%), showed ST depression in 59 (28%) (17 > or = 0.1 mV), and T wave changes in a further 69 (33%). The remaining 23 had Q waves (18), right bundle branch block (four), or ST elevation (one). During 8963 h of continuous ST segment monitoring (mean 42.3 h/patient), 132 episodes of transient myocardial ischaemia (104 silent) were recorded in 32 patients (15%). Forty patients (19%) had an adverse event (cardiac deaths (n = 3), non-fatal myocardial infarction (n = 6) and, emergency revascularisation (n = 31)). Both admission ECG ST depression (P = 0.02), and transient ischaemia (P < 0.001) predicted an increased risk of non-fatal myocardial infarction or death, while no patients with a normal ECG died or had a myocardial infarction. Adverse outcome was predicted by admission ECG ST depression (regardless of severity) (odds ratio (OR) 3.41) (P < 0.001), and maintenance beta blocker treatment (OR 2.95) (P < 0.01). A normal ECG predicted a favourable outcome (OR 0.38) (P = 0.04), while T wave or other ECG changes were not predictive of outcome. Transient ischaemia was the strongest predictor of adverse prognosis (OR 4.61) (P < 0.001), retaining independent predictive value in multivariate analysis (OR 2.94) (P = 0.03), as did maintenance beta blocker treatment (OR 2.85) (P = 0.01) and admission ECG ST depression, which showed a trend towards independent predictive value (OR 2.11) (P = 0.076). CONCLUSIONS: Patients with unstable angina and a normal admission ECG have a good prognosis, while ST segment depression predicts an adverse outcome. Transient myocardial ischaemia detected by continuous ST segment monitoring in such patients receiving optimal medical treatment provides prognostic information additional to that gleaned from the clinical characteristics or the admission ECG.

Fatal infantile mitochondrial myopathy due to cytochrome c oxidase deficiency.

A case of cytochrome c oxidase deficiency primarily affecting skeletal muscle is described. The child was admitted at 4 weeks due to failure to thrive and examination at that time revealed weakness and hypotonia. His condition deteriorated until at 11 weeks respiratory arrest necessitated artificial ventilation and death occurred at 14 weeks. Biochemical investigation showed lactic acidaemia and generalised aminoaciduria. Histochemical examination of muscle obtained at biopsy showed strong reactions for some oxidative enzymes, but by contrast cytochrome c oxidase could not be detected. Cytochrome c oxidase activity was less than 5% of control values in an extract of fresh muscle. The reduced-minus oxidised absorption spectra of muscle mitochondrial fractions prepared from post-mortem tissue showed an absence of cytochrome aa3 and a partial deficiency of cytochrome b. Ultra-structural examination showed abnormal mitochondria with loss of cristae and an abnormal granular matrix. The family history suggests autosomal recessive inheritance.

Proton irradiation of [18O]O2: production of [18F]F2 and [18F]F2 + [18F] OF2.

The production of 18F electrophilic reagents via the 18O(p,n)18F reaction has been investigated in small-volume target bodies made of aluminum, copper, gold-plated copper and nickel, having straight or conical bore shapes. Three irradiation protocols-single-step, two-step and modified two-step-were used for the recovery of the 18F activity. The single-step irradiation protocol was tested in all the target bodies. Based on the single-step performance, aluminum targets were utilized extensively in the investigation of the two-step and modified two-step irradiation protocols. With an 11-MeV cyclotron and using the two-step irradiation protocol, > 1Ci [18F]F2 was recovered reproducibly from an aluminum target body. Probable radical mechanisms for the formation of OF2 and FONO2 (fluorine nitrate) in the single-step and modified two-step targets are proposed based on the amount of ozone generated and the nitrogen impurity present in the target gases, respectively.

Dosimetric properties of neutron beams from the D--D reaction in the energy range from 6.8 to 11.1 MeV.

The tissue kerma in air, the tissue dose at maximum build-up, the relative depth dose on the central axis and the dose build-up characteristics were measured for neutrons produced by 6.8, 8.9 and 11.1 MeV deuterons on deuterium. The neutron beams were produced by a variable-energy cyclotron with a fully stopping deuterium gas target 20 cm long. Measurements were made in a 11.1cm x 11.1 cm field 126 cm from the target entrance window. The dose rate was found to increase rapidly with energy from 0.07 rad min-1 microamperemeter-1 at 6.8MeV to 0.35 rad min-1 muA-1 at 11.1 MeV. The entrance dose is about 50% of the dose maximum for each bombarding energy. The depth of the 95% dose level in the build-up region increased from 50 mg cm-2 at 6.8 MeV to 90 mg cm-2 at 11.1 MeV. The penetration was independent of the bombarding energy in the region investigated. Attenuation of the total dose to 50% of the maximum occurred at 10.2 +/- 0.1 g cm-2 for all three bombarding energies. The dose at the maximum is typically 14% higher than the tissue kerma in air.

Dosimetry measurements of 26, 35 and 45 MeV p-Be and p-Li neutron beams.

Dosimetric properties of neutron beams produced by stopping 26, 35 and 45 MeV protons in beryllium and lithium have been measured. The effects of filtering the p-Be beam with 6 cm of polyethylene have been investigated. The tissue kerma rate in air exhibited an energy dependence of approximately E3 and the rate for p-Be beams was approximately one-fifth of the rate for d-Be beams. The penetrability of the neutrons was significnatly enhanced by the use of the filter, but with a 50% attentuation in tissue kerma rate. The tissue kerma rate for the p-Li beam was nearly the same as that for the p-Be beam.

Infection with Ureaplasma urealyticum: is there a specific clinical and radiological course in the preterm infant?

BACKGROUND: Despite having mild early respiratory disease, many preterm babies develop chronic lung disease (CLD). Intrauterine infection with Ureaplasma urealyticum has been associated with preterm labour and CLD. OBJECTIVE: To test the hypothesis that infection with U urealyticum results in a specific clinical and radiological picture in the first 10 days of life. METHODS: Retrospective study of 60 ventilated babies < 30 weeks gestation, who had tracheal secretions tested for U urealyticum. Placental histology was reviewed by a paediatric pathologist for signs of chorioamnionitis. Chest radiographs were independently reviewed by two paediatric radiologists according to previously agreed criteria. All reviewers were blinded to the infection status of the babies. RESULTS: Twenty five babies were U urealyticum positive. These were more likely to experience chorioamnionitis (p = 0.004), premature rupture of membranes (p = 0.01), and spontaneous vaginal delivery (p = 0.09). U urealyticum positive babies had fewer signs of respiratory distress syndrome on early chest radiographs (p = 0.038), and they could be weaned from their ventilation settings (fraction of inspired oxygen (FIO(2)) and mean airway pressure) more quickly in the first few days. Subsequently U urealyticum positive babies deteriorated clinically and radiologically. More often they required ventilation to be restarted (p = 0.051), a higher proportion being ventilated on day 10 (p = 0.027) with higher FIO(2) (p = 0.001) and mean airway pressure (p = 0.002). Their chest radiographs showed more emphysematous changes as early as day 5 (p = 0.045), with a pronounced difference by day 10 (p = 0.009). CONCLUSIONS: Preterm ventilated babies with U urealyticum in their tracheal secretions have a different clinical and radiological course, with less acute lung disease but early onset of CLD, compared with those with negative cultures.

Colonic complication of acute lymphoblastic leukaemia.

We present four unusual colonic complications of acute lymphoblastic leukaemia which occurred during the early induction period of chemotherapy. These included a transverse colitis, a haemorrhagic proctitis, a caeco-colic intussusception and an ileo-colic intussusception complicating typhlitis. Although complications are rare, they should be considered in the differential diagnosis of abdominal pain in children undergoing chemotherapy.

Imaging of neonatal pulmonary sequestration including Doppler ultrasound.

Seven cases of neonatal pulmonary sequestration are reviewed which illustrate the varied clinical presentations and radiological findings. In four patients, real time ultrasound scanning was used to image the chest and the features are described. In three cases, the systemic supplying artery was demonstrated by duplex Doppler scanning and further invasive investigations were avoided; after a chest radiograph, this should be the examination of choice in the investigation of a neonate with a possible pulmonary sequestration.

Case report: primary intrathoracic rhabdomyosarcoma: a rare childhood malignancy.

Primary intrathoracic rhabdomyosarcoma is a rare tumour in childhood. Three cases are presented and the radiological findings and clinical course are reviewed. The radiological manifestations are varied but a rapidly growing soft tissue mass with compression of adjacent structures is the most common. A rare association with an underlying congenital pulmonary cyst is described. The prognosis is worse than for rhabdomyosarcoma at other sites, with a predisposition for cerebral metastases.

Arthrosonography of the irritable hip in childhood: a review of 1 year's experience.

A retrospective study of 87 children presenting acutely with an "irritable hip" was undertaken to assess the role of arthrosonography of the hip joint. Arthrosonography detected 52 hip-joint effusions, of which 16 were aspirated and an effusion confirmed in 14 (88%). In 82 cases plain radiography was compared with arthrosonography for the detection of hip-joint effusions. Of 47 children with a positive ultrasound diagnosis, 28 (59%) showed abnormal findings on plain radiographs and, of 35 cases with negative ultrasound findings, 22 (63%) had a negative diagnosis by plain radiography. Patients with more severe clinical signs were more likely to have an ultrasonic diagnosis of an effusion (87%-100%) than those with mild clinical signs (25%). The ultrasonic measurement of the hip-joint capsule to femoral neck distance was 2.2 mm +/- 0.5 mm (mean +/- 1 SD) in normal hips and 6.3 mm +/- 1.5 mm in the joints with effusions. Our study suggests that arthrosonographically the normal capsular space is less than 3 mm and the difference between the two sides less than 2 mm. It is suggested that hip arthrosonography is a more accurate method for detecting hip-joint effusions than plain radiography; it may help select cases for hospital admission and should be performed before aspiration is attempted.

Initial investigation of childhood urinary tract infection: does the plain abdominal X ray still have a role?

To reassess the plain abdominal X ray (AXR) in the initial investigation of childhood urinary tract infection, radiologists from four paediatric units prospectively collected data on the yield from the AXR in 683 children. Five children had renal calculi. All were detected on ultrasound, but one was not visible on the initial AXR. Four spinal abnormalities were identified, none of which prompted any action by the clinician involved. While the costs, in both financial and radiation risk terms, may be small, the benefit of the AXR appears equally small. Where expert paediatric ultrasonography is available we would recommend that the AXR be reserved for patients with haematuria, loin pain, family history of calculus disease, or where further urinary tract infection occurs despite a normal ultrasound scan.

Orogastric magnet removal of ingested disc batteries.

Ingestion of disc batteries by infants and small children is an increasing problem. Batteries that remain in the stomach can corrode and damage mucosa and/or produce poisoning. Between 1989 and 1992, 37 children who had swallowed a total of 46 disc batteries presented to the Royal Hospital for Sick Children, Edinburgh, and were referred for battery removal by use of an orogastric magnet under fluoroscopy. Thirty-nine batteries were removed successfully (without anesthesia) from 32 children, using a magnet attached to an orogastric tube. In three cases the battery had passed into the small bowel. In one case, magnet extraction failed, but the two batteries the child had ingested subsequently passed into the small bowel. In two cases the patients refused to swallow the tube. In one of these cases the battery was removed successfully by the magnet, with the patient under general anesthesia; in the other it passed spontaneously into the small bowel. The authors conclude that orogastric magnet removal is a minimally invasive, well-tolerated method of removing ingested disc batteries.

Transient synovitis: is there a need to aspirate hip joint effusions?

There is debate as to the optimal management of children with hip joint effusions especially regarding the decision to aspirate. The objective of this study was to determine whether there is a need to aspirate hip joint effusions detected on ultrasound in patients with clinical transient synovitis (TS) and to identify the natural history of these effusions. Twenty-five children with proven hip joint effusions were followed up sequentially by clinical and radiological examination until symptom free. The mean age was 6 years with equal right/left distribution. No child underwent hip aspiration and no cases of sepsis were missed. The median size of hip effusion detected on ultrasound at presentation was 9 mm. At 7 days 60% (15/25) of patients had a normal clinical examination with no detectable effusion on ultrasound. At 14 days 16% (4/25) had an effusion detectable on ultrasound but they were all pain and limp free and their effusions were reducing in size. These results support the known benign nature of TS and that it will settle with conservative treatment.