Placental growth factor in suspected preterm pre-eclampsia: a review of the evidence and practicalities of implementation.

Despite extensive research, the pathophysiology and prevention of pre-eclampsia remain elusive, diagnosis is challenging, and pre-eclampsia remains associated with adverse maternal and perinatal outcomes. Angiogenic biomarkers, including placental growth factor (PlGF) and soluble fms-like tyrosine kinase 1 (sFlt-1), have been identified as valuable biomarkers for preterm pre-eclampsia, accelerating diagnosis and reducing maternal adverse outcomes by risk stratification, with enhanced surveillance for high-risk women. PlGF-based testing is increasingly being implemented in clinical practice in several countries. This review provides healthcare providers with an understanding of the evidence for PlGF-based testing and describes the practicalities and challenges to implementation. TWEETABLE ABSTRACT: Placental growth factor in pre-eclampsia: evidence and implementation of testing.

Brain abnormalities and neurodevelopmental delay in congenital heart disease: systematic review and meta-analysis.

OBJECTIVES: Studies have demonstrated an association between congenital heart disease (CHD) and neurodevelopmental delay. Neuroimaging studies have also demonstrated a high incidence of preoperative brain abnormalities. The aim of this study was to perform a systematic review to quantify the non-surgical risk of brain abnormalities and of neurodevelopmental delay in infants with CHD. METHODS: MEDLINE, EMBASE and The Cochrane Library were searched electronically without language restrictions, utilizing combinations of the terms congenital heart, cardiac, neurologic, neurodevelopment, magnetic resonance imaging, ultrasound, neuroimaging, autopsy, preoperative and outcome. Reference lists of relevant articles and reviews were hand-searched for additional reports. Cohort and case-control studies were included. Studies reporting neurodevelopmental outcomes and/or brain lesions on neuroimaging in infants with CHD before heart surgery were included. Cases of chromosomal or genetic abnormalities, case reports and editorials were excluded. Between-study heterogeneity was assessed using the I(2) test. RESULTS: The search yielded 9129 citations. Full text was retrieved for 119 and the following were included in the review: 13 studies (n = 425 cases) reporting on brain abnormalities either preoperatively or in those who did not undergo congenital cardiac surgery and nine (n = 512 cases) reporting preoperative data on neurodevelopmental assessment. The prevalence of brain lesions on neuroimaging was 34% (95% CI, 24-46; I(2) = 0%) in transposition of the great arteries, 49% (95% CI, 25-72; I(2) = 65%) in left-sided heart lesions and 46% (95% CI, 40-52; I(2) =18.1%) in mixed/unspecified cardiac lesions, while the prevalence of neurodevelopmental delay was 42% (95% CI, 34-51; I(2) = 68.9). CONCLUSIONS: In the absence of chromosomal or genetic abnormalities, infants with CHD are at increased risk of brain lesions as revealed by neuroimaging and of neurodevelopmental delay. These findings are independent of the surgical risk, but it is unclear whether the time of onset is fetal or postnatal.

Accuracy, comprehensibility, and use of material safety data sheets: a review.

OBJECTIVES: Material safety data sheets (MSDSs) are used in workplaces to communicate to workers the hazards of chemical products. This article describes a review of the peer-reviewed scientific literature regarding the accuracy, comprehensibility and use of MSDSs in the workplace. METHODS: Articles were retrieved via a systematic search of indexes and databases, followed by hand searching and citation index searching. Two reviewers independently read and coded the articles using an iterative matrix. RESULTS: Of the 280 unique articles retrieved, 24 fit the review criteria. Eligible articles included a range of methodologies: laboratory analyses, site audits, surveys and qualitative inquiry. Articles were grouped into three main topic categories: accuracy and completeness, awareness and use, and comprehensibility. Accuracy and completeness were found to be relatively poor, with the majority of studies presenting evidence that the MSDSs under review did not contain information on all the chemicals present, including those known to be serious sensitizers or carcinogens. Poor presentation and complex language were consistently associated with low comprehensibility among workers. Awareness and use of MSDSs was suboptimal in workplaces where these factors were studied. CONCLUSIONS: Despite the fact that these studies varied in methodology and spanned a period of more than 15 years, a number of common themes emerged regarding inaccuracies, incompleteness, incomprehensibility and overall low use of MSDSs. The results of the literature review suggest that there are serious problems with the use of MSDSs as hazard communication tools. The article concludes with recommendations for governments, regulatory bodies, and occupational health and safety personnel to seriously reassess the ways in which MSDSs are written, monitored, regulated, and used.

A passive acoustic device for real-time monitoring of the efficacy of shockwave lithotripsy treatment.

Extracorporeal shockwave lithotripsy (ESWL) is the preferred modality for the treatment of renal and ureteric stone disease. Currently X-ray or ultrasound B-scan imaging are used to locate the stone and to check that it remains targeted at the focus of the lithotripter during treatment. Neither imaging modality is particularly effective in allowing the efficacy of treatment to be judged during the treatment session. A new device is described that, when placed on the patient's skin, can passively monitor the acoustic signals that propagate through the body after each lithotripter shock, and which can provide useful information on the effectiveness of targeting. These acoustic time histories are analyzed in real time to extract the two main characteristic peak amplitudes (m(1) and m(2)) and the time between these peaks (t(c)). A set of rules based on the acoustic parameters was developed during a clinical study in which a complete set of acoustic and clinical data was obtained for 30 of the 118 subjects recruited. The rules, which complied with earlier computational fluid dynamics (CFD) modeling and in vitro tests, allow each shock to be classified as "effective" or "ineffective." These clinically-derived rules were then applied in a second clinical study in which complete datasets were obtained for 49 of the 85 subjects recruited. This second clinical study demonstrated almost perfect agreement (kappa = 0.94) between the number of successful treatments, defined as >50% fragmentation as determined by X-ray at the follow-up appointment, and a device-derived global treatment score, TS(0), a figure derived from the total number of effective shocks in any treatment. The acoustic system is shown to provide a test of the success of the treatment that has a sensitivity of 91.7% and a specificity of 100%. In addition to the predictive capability, the device provides valuable real-time feedback to the lithotripter operator by indicating the effectiveness of each shock, plus an indication TS(t) of the cumulative effectiveness of the shocks given so far in any treatment, and trends in key parameters. This feedback would allow targeting adjustments to be made during treatment. An example is given of its application to mistargeting because of respiration.

Characterization of a polymer film optical fiber hydrophone for use in the range 1 to 20 MHz: a comparison with PVDF needle and membrane hydrophones.

A small aperture wideband ultrasonic optical fiber hydrophone is described. The transduction mechanism is based on the detection of acoustically induced changes in the optical thickness of a 25-microm thick parylene polymer film acting as a low finesse Fabry Perot (FP) interferometer that is deposited directly onto the end of a single mode optical fiber. The acoustic performance compares favorably with that of PVDF needle and membrane hydrophones with a peak noise-equivalent-pressure (without signal averaging) of 10 kPa over a 25-MHz measurement bandwidth, a wideband response to 20 MHz, and a near omnidirectional performance at 10 MHz. The dynamic range was 60 dB with an upper limit of linear detection of 11 MPa and a temporal stability of <5% over a period of 20 h. The hydrophone can also measure temperature changes with a resolution of 0.065 degrees C, offering the prospect of making simultaneous acoustic pressure and temperature measurements. The transduction parameters of the FP sensing element were measured, yielding an ultrasonic acoustic phase sensitivity of 0.075 rad/MPa and a temperature phase sensitivity of 0.077 rad/ degrees C. The ability to achieve high acoustic sensitivity with small element sizes and to repeatably fabricate rugged sensor downleads using polymer deposition techniques suggests that this type of hydrophone can provide a practical alternative to piezoelectric hydrophone technology.

A two-dimensional hydrophone array using piezoelectric PVDF.

A new development in ultrasound measurement technology-a two-dimensional hydrophone array-is presented. Using the established technology of PVDF ultrasound sensors, this novel hydrophone array has 64 circular elements (each of 0.2 mm diameter) arranged in an 8/spl times/8 pattern with 1 mm spacing between element centers. Construction of the hydrophone array is discussed, and results of a series of measurements to characterize its performance are presented. Hydrophone elements exhibit a flat frequency response (/spl plusmn/0.8 dB over the frequency range 1-25 MHz) and have an effective radius that appears to have minimal frequency dependency (within /spl plusmn/8% of mean value) and is within 8% of the nominal sensor radius. The hydrophone array performance also is assessed in terms of dynamic range, interelement variation, and acquisition time. Applications of this new technology (such as mapping of transducer fields, assessment of diagnostic ultrasound fields, and use in point source-array receiver nondestructive testing) are discussed.

Evidence that potassium channels make a major contribution to SIN-1-evoked relaxation of rat isolated mesenteric artery.

1. The NO donor 3-morpholino-sydnonimine (SIN-1; 0.01-10 microM) evoked concentration-dependent relaxation of rat isolated mesenteric arteries pre-constricted with phenylephrine (1-3 microM). The relaxation to SIN-1 was not significantly different between endothelium-intact or denuded arterial segments or segments in which basal nitric oxide (NO) synthesis was inhibited (n = 8; P > 0.05). In contrast, the membrane permeable analogue of guanosine 3':5'-cyclic monophosphate (cyclic GMP), 8-Br-cyclic GMP (0.01-1 mM), was much less effective in relaxing intact than denuded arterial segments or intact arterial segments pre-incubated with NO synthase blockers (n = 4; P < 0.01). 2. 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 microM; 10 min) alone, did not alter SIN-1-evoked relaxation in any tissues (n = 5; P > 0.05). However, in parallel experiments, ODQ almost completely inhibited both basal and SIN-1-stimulated production of cyclic GMP in both the presence and absence of NO synthase blockers (n = 6; P < 0.01) indicating that full relaxation to SIN-1 can be achieved in the absence of an increase in cyclic GMP. 3. Exposure of endothelium-intact arterial segments to the potassium channel blocker charybdotoxin (50 nM; 10 min), significantly inhibited SIN-1-evoked relaxation, reducing the maximum response by around 90% (n = 5; P < 0.01). In contrast, in arterial segments in which either the endothelial cell layer had been removed or basal NO synthesis inhibited, relaxation to SIN-1 was not reduced in the presence of charybdotoxin (n = 6; P > 0.05). However, in the presence of NO synthase blockers and L-arginine (300 microM) together, charybdotoxin did significantly inhibit SIN-1-evoked relaxation to a similar extent as intact tissues (maximum response induced by around 80%; n = 4; P < 0.01). 4. Pre-incubation with apamin (30 nM; 10 min) or glibenclamide (10 microM; 10 min) did not alter SIN-1-evoked relaxation of phenylephrine-induced tone in any tissues (n = 4 and n = 6, respectively; P > 0.05). However, in the presence of either ODQ and apamin, or ODQ and glibenclamide, SIN-1-evoked relaxation was significantly attenuated in intact arterial segments and segments in which NO synthesis was blocked. 5. Exposure of intact arterial segments to charybdotoxin and apamin, in the presence of NO synthase blockers, also significantly inhibited SIN-1-evoked relaxation, reducing the maximum response by around 80% (n = 4; P < 0.01). 6. Addition of superoxide dismutase (SOD; 30 u ml-1), potentiated relaxations to SIN-1 in all tissues, but did not alter the effects of charybdotoxin and ODQ and SIN-1-evoked relaxation. 7. These data show that although relaxation to the NO-donor SIN-1 is not significantly different between endothelium-intact and denuded arterial segments, the mechanisms which mediate SIN-1-evoked relaxation in the rat isolated mesenteric artery appear to be modulated by the basal release of endothelium-derived NO. In the presence of an intact endothelial cell layer, the major mechanism for SIN-1-evoked relaxation appears to be the activation of charybdotoxin-sensitive potassium channels. In contrast, when basal NO synthesis is inhibited, SIN-1 appears to cause full relaxation by both the activation of a charybdotoxin-sensitive pathway and the stimulation of soluble guanylyl cyclase.

Clinical chemistry outside laboratories: report of a second survey.

The growth in the use of small portable analysers outside hospital laboratories has been a cause of concern to laboratory practitioners. This has been partly because of a perceived threat to laboratory careers and partly because of fears that the quality of testing would be poor, with a consequent danger of patients being placed at risk. The evidence in this paper indicates that the use of equipment outside laboratories is still increasing in many areas. Despite the fears which have been expressed, little attention is being given to operator training, service costs, safety and many other aspects; only rarely has responsibility for the quality of results been accepted.

External quality assessment of quantitative urinary analysis.

An external quality-assessment scheme was initiated among a group of 13 clinical chemistry laboratories for the urinary analysis of calcium, chloride, creatinine, glucose, osmolality, phosphate, potassium, protein, sodium, urate and urea and also for the estimation of creatinine clearance. The greatest inter-laboratory imprecision occurred in the assay of urinary protein. The results of the survey are compared with similar schemes elsewhere and their significance discussed.