Confirmatory testing illustrates additional risks for structural sex chromosome abnormalities in fetuses with a non‐invasive prenatal screen positive for monosomy X

More and more women rely on non‐invasive prenatal screening (NIPS) to detect fetal sex and risk for aneuploidy. The testing applies massively parallel sequencing or single nucleotide polymorphism (SNP) microarray to circulating cell‐free DNA to determine relative copy number. In addition to trisomies 13, 18, and 21, some labs offer screening for sex chromosome abnormalities as part of their test. In this study, an index neonate screened positive for monosomy X and had discordant postnatal chromosomes indicating an X;autosome translocation. This patient prompted a retrospective chart review for similar cases at a large NIPS testing center. The review found 28 patients with an abnormal NIPS for monosomy X who were eventually diagnosed with additional discrepant structural sex chromosome abnormalities including translocations, isochromosomes, deletions, rings, markers, and uniparental disomy. The majority of these were mosaic with monosomy X, but in seven cases, there was no evidence of mosaicism on confirmatory testing. The identification of multiple sex chromosome aneuploidies in these cases supports the need for additional genetic counseling prior to NIPS testing and following abnormal NIPS results that are positive for monosomy X. This finding broadens our knowledge about the variable outcomes of positive monosomy X NIPS results and emphasizes the importance of confirmatory testing and clinical follow up for these patients.     

Patient dose management in digital radiography

Purpose:

To present the experience in patient dose management and the development of an online audit tool for digital radiography.

Materials and methods:

Several tools have been developed to extract the information contained in the DICOM header of digital images, collect radiographic parameters, calculate patient entrance doses and other related parameters, and audit image quality.

Results:

The tool has been used for mammography, and includes images from over 25,000 patients, over 75,000 chest images, 100,000 computed radiography procedures and more than 1,000 interventional radiology procedures. Examples of calculation of skin dose distribution in interventional cardiology based upon information of DICOM header and the results of dosimetric parameters for cardiology procedures in 2006 are presented.

Conclusion:

Digital radiology has great advantages for imaging and patient dose management. Dose reports, QCONLINE systems and the MPPS DICOM service are good tools to optimise procedures and to manage patient dosimetry data. The implementation of the ongoing IEC-DICOM standard for patient dose structured reports will improve dose management in digital radiology.     

Genetic polymorphisms and environmental risk of lung cancer: a review

Lung cancer results from man-made and natural environmental exposures acting in concert with both genetic and acquired characteristics. Chronic inhalation of cigarette smoke is a major risk factor, and environmental tobacco exposure can cause lung cancer in life-long neversmokers. Air pollution, indoor-radon exposure, occupational exposures, dietary, physical activity, and reproductive history have been identified as independent or contributing risk factors for lung cancer. Because only a small portion of smokers develops the disease, genetic susceptibility can contribute to the risk. Developments in molecular biology have led to the discovery of biological markers that increase predisposition to lung carcinogenesis. Therefore, the high-risk genotype of an individual can be determined easily. Because of the great number of carcinogen-activating and -detoxifying enzymes, the variation in their expression, the complexity of exposures to tobacco carcinogens, and the existence of multiple alleles at loci of those enzymes results in differential susceptibilities of individuals. As lung cancer is a multifactorial disease, an improved understanding of the interplay of environmental and genetic polymorphisms at multiple loci can help identify individuals who are at increased risk for lung cancer. Hopefully, in the future we will be able to screen for lung cancer susceptibility by using specific biomarkers.     

Apnoea induced by airflow obstruction

Total obstruction of the airways caused all respiratory efforts to stop on 15 occasions in 10 preterm babies. This was not seen in 60 studies on 38 term babies. These findings suggest that failure to achieve an oral airway may not be the only mechanism by which upper airway obstruction might cause the cot death syndrome.     

Complicated diverticulitis during pregnancy

The authors report a case of perforated diverticulitis with presence of a fistulous tract between a peridiverticular abscess and the uterus during pregnancy with favorable outcome under medical treatment. The purpose of this case report is to illustrate specific imaging findings and clinical management of diverticulitis during pregnancy.     

Life-History Patterns in Reference and Metal-Exposed Earthworm Populations

The growth and development of F1 Lumbricus rubellus bred from reference and one metal-exposed (smelter) populations were assessed in soils from both sites. In the clean soil, faster growth (as reflected by mean weight) and maturation were found at selected time intervals for the smelter worms. This result is in agreement with predictions from life-cycle models, which indicate that polluted-site populations will be adapted for faster growth, earlier maturation and increased reproductive effort. Life-history adaptation is not however the only explanation for the differences in maturation rates found. During the exposures, mortality of smelter worms was higher than for the reference strain. This resulted in a reduction in the density of the smelter strain. In earthworms, both growth rate and maturation time are known to be density dependent. Thus it is probable that density-mediated responses of growth and development, rather than adaptation, are primarily responsible for the observed life-history.Exposure of the two strains to the smelter site soil was carried out to quantify differences in performance indicative of physiological resistance in the smelter worms. In fact, no consistent differences in growth or maturation were found. Thus it is unlikely that growth and development responses of Lumbricus rubellus are adapted to the metals present in soils at the smelter site.     

Validity of forced expiratory flow volume loops in neonates.

It is claimed that suddenly squeezing a newborn baby''s trunk with a pressure of 3-4 kPa produces a flow volume curve that can be used to measure the function of the small airways. If the squeeze is applied during expiration rather than at the end of inspiration, however, anomalous results may be obtained. One possible explanation is that the babies are limiting expiratory flow by making inspiratory efforts in response to the applied external pressure. The response of 10 healthy term neonates to forced expiration was studied by using an oesophageal balloon. The squeeze was provided by an inflatable jacket, and measurements of oesophageal pressure and jacket pressure were recorded, as well as flow and volume changes at the mouth. Two hundred and twenty one squeezes were performed at different points in the respiratory cycle. In 188 squeezes an inspiratory effort was evident before the oesophageal pressure reached a plateau (mean time to peak pressure = 155 ms). For the remaining squeezes a plateau pressure was associated with closure or narrowing of the upper airway in most of the babies. When the squeeze was applied at low lung volumes the inspiratory effort was significantly earlier and stronger than around end inspiration. Thus a baby makes a reflex inspiratory response to chest compression that may interfere with the measurement of airway function when this technique is used.     

Efficiency of manual resuscitators at birth.

The effectiveness of five neonatal/paediatric manual resuscitators was assessed in a group of babies born by caesarean section. Results showed that devices incorporating a large volume reservoir produced the greatest tidal volume, while those with smaller volume reservoirs could not be considered satisfactory for routine use during neonatal resuscitation.     

Effects of positive end expiratory pressure during ventilation of the preterm infant.

Twenty two babies receiving artificial ventilator support were studied on 29 occasions to determine the effects of low levels of positive end expiratory pressure. Mean positive end expiratory pressure during these studies was 2.6 cm H2O. Changes in tidal volume, minute volume, compliance, and transcutaneous gas trends produced by the use of positive end expiratory pressure were investigated. Positive end expiratory pressure consistently caused a rise in transcutaneous oxygen tension. Changes in transcutaneous carbon dioxide tension after the introduction of positive end expiratory pressure were less consistent and not of the same magnitude as the observed reduction in minute ventilation. Compliance values fell with the use of positive end expiratory pressure.     

Manipulation of ventilator settings to prevent active expiration against positive pressure inflation.

Recent publications have suggested that in infants receiving artificial ventilatory support a particular pattern of interaction between spontaneous breaths and ventilator inflations (active expiration against each ventilator inflation) may be important in the production of pneumothoraces. We have looked at patterns of interaction from 47 preterm infants studied on 51 occasions. We found that active expiration against the ventilator occurred on a total of 16 occasions. This pattern was prevented on 14 occasions by altering the ventilator settings. In two other babies, the pattern persisted but neither baby developed a pneumothorax.