Circulating levels of the antiangiogenic marker sFLT-1 are increased in first versus second pregnancies

Preeclampsia is far more common in women's first pregnancy but the mechanism of this association is unknown. Altered angiogenesis, marked by increased levels of circulating soluble fms-like tyrosine kinase (sFlt-1), an inhibitor of placental growth factor (PlGF) and vascular endothelial growth factor, has been implicated in the pathogenesis of preeclampsia. We tested the hypothesis that nulliparous women demonstrate increased sFlt-1 levels compared with multiparous women, suggesting an overall increase in relative antiangiogenesis during first pregnancies. We measured sFlt-1 and PlGF levels in early pregnancy serum samples from the first 2 completed pregnancies of 97 women who participated in the MOMS cohort study. Repeated measures analyses demonstrated that sFlt-1 levels were significantly increased in first compared with second pregnancies (877+/-598 pg/mL vs 728+/-399 pg/mL; P=.01) but there was no significant difference in PlGF levels (45.3+/-40.7 pg/mL vs 40.1+/-31.9 pg/mL; P=.14). After adjusting for age, gestational age, blood pressure, body mass index, smoking, and the interpregnancy time interval, the residual decrease in sFlt-1 levels from the first to the second pregnancy remained significant at 107 pg/mL (P=.04). Significant interaction between ethnicity and pregnancy order on sFlt-1 levels was observed such that Hispanic women demonstrated greater sFlt-1 levels than white women during their first pregnancy but lower levels in their second pregnancies. Increased sFlt-1 secretion in first versus second pregnancies may account in part for the increased risk of preeclampsia among nulliparous women. Additional studies are needed to verify these findings and to further examine ethnic differences in angiogenesis factors and their potential impact on the incidence of preeclampsia.     

Comparison of methods for the dynamic calibration of electromagnetic flowmeters

The response characteristics of an electromagnetic blood flowmeter and associated recording system were determined both by an electronic method and by Fourier transform of the impulse response. Amplitude and phase responses were measured to 25Hz with the flow-meter filters set at nominal 5, 15 and 50 Hz. Agreement between the two methods was good unless the 50 Hz filter was used. The amplitude of the input was reduced by approximately 50% at 10 Hz using the 5 Hz filter and by 10% using the 50 Hz filter. The use of these filters in the clinical situation may cause significant loss of information. Alternatively, the use of signal-averaging techniques may extend the range of reliable recordings.     

Factors affecting the sensitivity of X-ray films used for whole-body autoradiography

The sensitivities of five X-ray films commonly used for autoradiography of whole-body sections and thin-layer chromatograms were determined. The films tested were Kodak NS-2T, XAR-5, Industrex C, Agfa-Gevaert Osray M3 and CEAverken Singul-X. The order of sensitivity, from greatest to least, was found to be NS-2T, Osray M3, XAR-5, Singul-X and Industrex C. Increases in sensitivity following extended development were demonstrated for Industrex C. A literature review has revealed confusion in the use, in whole-body autoradiography, or various measures of autoradiographic response, which, in view of the simple relationship between radiographic optical density and absorbed dose, need not have arisen.     

Conjuctivitis and keratoconjunctivitis associated with primary immunodeficiency diseases.

Nineteen patients with a variety of well-defined primary immunodeficiency diseases were examined for ocular abnormalities. Eight patients with low levels, or absence, of all the major serum immunoglobulins had conjunctivitis or keratoconjunctivitis associated with bacterial infection. The remaining 11 patients, who had at least one immunoglobulin class present in normal concentration in the serum, showed no inflammatory ocular lesion. Absence of only IgA, the major tear immunoglobulin, did not predispose the eye to these lesions.