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Biomedical subjects

S Campbell

Publications and source records attributed to S Campbell.

At least 307 records · Page 17Linked to original sources
PubMed1996

Prediction of pre-eclampsia by abnormal uterine Doppler ultrasound and modification by aspirin.

OBJECTIVE: To assess the effect of low dose aspirin on severe pre-eclampsia when given to women identified as high risk by abnormal uterine artery Doppler ultrasound. DESIGN: Women with abnormal uterine artery flow velocity waveforms were recruited to the CLASP trial at 24 weeks. Abnormal uterine artery waveforms, with a high resistance index or an early diastolic notch, were identified at the 18-22 week anomaly scan and confirmed at 24 weeks. Of those women with persistently abnormal waveforms, 63 agreed to enter the CLASP trial. Three women were lost to follow up and five did not comply. Thus, 60 were randomised: 29 to placebo and 31 to low dose aspirin (60 mg daily) and analysis by intention to treat is reported. RESULTS: There were nine cases (29%) of pre-eclampsia in the aspirin group and twelve (41%) in the placebo group (odds ratio (OR) 0-58, confidence interval (CI) 0.2-1.69, P = 0.32). Severe pre-eclampsia developed in four women in the aspirin group and eleven women in the placebo group (OR 0.24, CI 0.07-0.88, P = 0.03) and intrauterine growth retardation occurred in eight cases in the aspirin group and twelve in the placebo group (OR 0.49, CI 0.17-1.47). The mean birthweight and gestation at delivery were 2.69 kg and 38.5 weeks in the aspirin group and 2.38 kg and 37.4 weeks in the placebo group, neither of which were statistically significant using the unpaired t test; P = 0.09 and P = 0.23, respectively. CONCLUSION: In high risk pregnancy low dose aspirin commenced at 24 weeks may reduce the incidence of severe pre-eclampsia.

Adolescent↗
PubMed1996

Analysis of Rous sarcoma virus Gag protein by mass spectrometry indicates trimming by host exopeptidase.

We have used electrospray ionization-mass spectrometry to investigate Gag protein structure and processing in Rous sarcoma virus, the prototype of the avian sarcoma and leukemia viruses. Molecular masses determined for the mature virion proteins MA, CA, NC, and PR agree closely with those predicted by currently accepted models for their structures. However, the data for p10 imply that only about 10% of the product has the predicted mass while the remainder is missing the C-terminal methionine residue. Molecular masses also were obtained for products generated by PR cleavage in vitro of a Gag precursor polyprotein expressed in Escherichia coli. The data confirm the predicted Gag cleavage sites for PR. Thus, carboxypeptidase activity appears to be responsible for generating the des-Met form of p10. The same activity may account for the small amount of the mature des-Met CA, as previously reported. Analysis of cleavage products generated in vitro also serves to define the PR processing site separating the p2a and p2b peptides, Asn-164-Cys-165. In conjunction with published characterizations of these two peptides processed from the segment of Gag between MA and p10, these data suggest trimming of p2b by an aminopeptidase. Finally, the molecular masses determined for the MA-related species p19f, p23, and p35 now accurately define the structures of these proteins.

Amino Acid Sequence↗
PubMed1996

Measurement of volume flow with time domain and M-mode imaging: in vitro and in vivo validation studies.

Color velocity imaging quantification is a commercially available technique that estimates volume flow within vessels by combining velocity data, acquired by time domain correlation, with vessel diameter measurements obtained by M-mode imaging. By integrating the velocity profile over time, quantitative volume flow calculations may be made. To investigate the accuracy of this system, we used two flow phantoms over a range of steady and pulsatile flows for in vitro evaluation, and the common carotid artery of 10 women on five consecutive occasions was insonated for in vivo assessment. In flow phantom studies, accuracy was within 8% for flows above 200 ml/min, but decreased at lower flows depending on the depth, beam-vessel angle used, and steering of the beam. At angles greater than 70 degrees, velocity errors made quantitative measurement of flow unreliable, whereas at angles less than 30 degrees, the increased error in calculating vessel diameter led to large errors of area estimation, and hence made flow measurements unreliable. For the in vivo studies on the carotid artery the intraoperator repeatability values for the three operators were 9.92% (A), 13.74% (B), and 13.24% (C). The interoperator repeatability for the group was 15.30%. This study suggests that the color velocity imaging quantification technique is an accurate and reproducible method of assessing volume flow in vessels. However, in our experience, obtaining volume flow data is more time consuming and operator dependent than traditional Doppler techniques. The color velocity imaging quantification system may be of use in monitoring conditions in which changes in volume flow in a vessel or to an organ is an important part of the disease process.

Blood Flow Velocity↗