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Biomedical subjects

K Spencer

Publications and source records attributed to K Spencer.

At least 73 records · Page 4Linked to original sources
PubMed2000

Fetal heart rate in chromosomally abnormal fetuses.

OBJECTIVES: To determine the effects of chromosomal defects on fetal heart rate at 10-14 weeks of gestation. METHODS: Fetal heart rate at 10-14 weeks of gestation in 1061 chromosomally abnormal fetuses was compared to that from 25,000 normal pregnancies. The chromosomally abnormal group included 554 cases of trisomy 21, 219 cases of trisomy 18, 95 of trisomy 13, 50 of triploidy, 115 of Turner syndrome and 28 of sex chromosome abnormalities other than Turner syndrome. RESULTS: In the normal group, fetal heart rate decreased from a mean value of 170 beats per minute (bpm) at 35 mm of crown-rump length to 155 bpm at 84 mm crown-rump length. In trisomy 21, trisomy 13 and Turner syndrome fetal heart rate was significantly higher, in trisomy 18 and triploidy the heart rate was lower and in other sex chromosome defects it was not significantly different from normal. Fetal heart rate was above the 95th centile of the normal range in 10%, 67% and 52% of fetuses with trisomy 21, trisomy 13 and Turner syndrome, respectively. The fetal heart rate was below the 5th centile in 30% of fetuses with triploidy and 19% of those with trisomy 18. CONCLUSIONS: Trisomy 21, trisomy 13 and Turner syndrome are associated with fetal tachycardia, whereas in trisomy 18 and triploidy there is fetal bradycardia. Inclusion of fetal heart rate in a first-trimester screening program for trisomy 21 by a combination of maternal age and fetal nuchal translucency thickness is unlikely to provide useful improvement in sensitivity.

Chromosome Aberrations↗
PubMed2000

First trimester maternal serum free beta human chorionic gonadotrophin and pregnancy associated plasma protein A as predictors of pregnancy complications.

OBJECTIVE: To examine the value of first trimester maternal serum free beta human chorionic gonadotrophin (beta hCG) and pregnancy associated plasma protein A (PAPP-A) as predictors of pregnancy complications. DESIGN: Screening study. SETTING: Antenatal clinics. POPULATION: Singleton pregnancies at 10-14 weeks of gestation. METHODS: Maternal serum free beta hCG and PAPP-A were measured at 10-14 weeks of gestation in 5,584 singleton pregnancies. In the 5,297 (94.9%) pregnancies with complete follow up free beta hCG and PAPP-A were compared between those with normal outcome and those resulting in miscarriage, spontaneous preterm delivery, pregnancy induced hypertension or fetal growth restriction and in those with pre-existing or gestational diabetes. RESULTS: Maternal serum PAPP-A increased and beta hCG decreased with gestation. The multiple of median maternal serum PAPP-A was significantly lower in those pregnancies resulting in miscarriage, pregnancy induced hypertension, growth restriction and in those with pre-existing or gestational diabetes mellitus, but not in those complicated by spontaneous preterm delivery. The level was < 10th centile of the reference range in about 20% of the pregnancies that subsequently resulted in miscarriage or developed pregnancy induced hypertension or growth restriction, and in 27% of those that developed gestational diabetes. Maternal serum free beta hCG was < 10th centile of the reference range in about 15% of the pregnancies that subsequently resulted in miscarriage or developed pregnancy induced hypertension or growth restriction, and in 20% of those that developed gestational diabetes. CONCLUSION: Low maternal serum PAPP-A or beta hCG at 10-14 weeks of gestation are associated with subsequent development of pregnancy complications.

Adolescent↗
PubMed2000

One stop clinic for assessment of risk for fetal anomalies: a report of the first year of prospective screening for chromosomal anomalies in the first trimester.

OBJECTIVE: To evaluate the introduction of a one stop multidisciplinary clinic for screening for fetal chromosomal abnormalities in the first trimester by a combination of maternal serum biochemistry and ultrasonography providing a risk of chromosomal abnormalities within a one hour clinic visit. DESIGN: One year retrospective review of screening performance. POPULATION: All women attending for routine antenatal care. The population included 4,190 singleton pregnancies in women of all ages screened between 10 weeks and 3 days and 13 weeks and 6 days of gestation between the periods 1 June 1998 and 31 May 1999 in a district general hospital antenatal clinic. METHODS: All women booked into the clinic were offered screening by a combination of maternal serum free beta human chorionic gonadotrophin (hCG) and pregnancy associated plasma protein A (PAPP-A) and fetal nuchal translucency thickness. Women at increased risk of carrying a fetus with trisomy 21 or trisomy 18/13 (> or =1 in 300 at sampling) were offered counselling and an invasive diagnostic procedure. Follow up of the outcome of all pregnancies was carried out. MAIN OUTCOME MEASURES: The detection rate for trisomy 21, trisomy 18/13 and all aneuploides, false positive rate, uptake of screening, uptake of chorionic villus sampling in women identified at increased risk and fetal loss after chorionic villus sampling. RESULTS: Overall 97.6% of the women (4,088/4,190) accepted first trimester screening. The rate of detection of trisomy 21 was 86% (6/7), for trisomy 18/13 100% (9/9) and for all aneuploides 95% (18/19). Fetal death at presentation was found in 1.6% of pregnancies (69/4,088). Of women who accepted screening, 6.1% (257/4,088) presented too late for fetal nuchal translucency measurement and 6.5% of the women (271/4,088) presented too early. The false positive rate was 6.7% (253/3,762). Uptake of invasive testing was 83% (207/253). CONCLUSION: First trimester prenatal screening for chromosomal abnormalities using a combination of maternal serum biochemistry and fetal nuchal translucency thickness can achieve detection rates in excess of 90%. These services can be provided in a one stop multidisciplinary clinic.

Adult↗
PubMed2000

Normal values of regional left ventricular endocardial motion: multicenter color kinesis study.

Our goal was to establish normal values for quantitative color kinesis indexes of left ventricular (LV) wall motion over a wide range of ages, which are required for objective diagnosis of regional systolic and diastolic dysfunction. Color-encoded images were obtained in 194 normal subjects (95 males, 99 females, age 2 mo to 79 yr) in four standard views. Quantitative indexes of magnitude and timing of systolic and diastolic function were studied for age- and gender-related differences. Normal limits of all ejection and filling indexes were in a narrow range (< or =25% of the mean), with no major gender-related differences. Despite invariable ejection fractions, both peak filling and ejection rates decreased with age (30 and 20%, correspondingly) with a concomitant increase in mean filling and ejection times, resulting in five- and twofold increases in the late to early filling and ejection ratios, correspondingly. Diastolic asynchrony increased with age (from 4.7 +/- 2.0 to 6.4 +/- 3.2 from the 2nd to 7th decade). The normal values of color kinesis indexes should allow objective detection of regional LV systolic and diastolic dysfunction.

Adolescent↗
PubMed2000

Screening for trisomy 13 by fetal nuchal translucency and maternal serum free beta-hCG and PAPP-A at 10-14 weeks of gestation.

In 42 cases of trisomy 13 at 10-14 weeks of gestation, compared with 947 controls, the median multiple of the median (MoM) of maternal serum free beta-human chorionic gonadotrophin (beta-hCG) and pregnancy associated plasma protein A (PAPP-A) was significantly decreased (0.506 MoM and 0.248 MoM respectively), whilst fetal nuchal translucency was increased (2.872 MoM). In 38% and 71% of cases of trisomy 13 maternal serum free beta-hCG and PAPP-A was below the 5th centile of the appropriate normal range for gestation and in 62% of cases the nuchal translucency was above the 95th centile. When combined together in a multivariate algorithm with maternal age, 90% of cases of trisomy 13 could be detected at a 0.5% false positive rate or 84% at a 0.1% false positive rate. We conclude that specific trisomy 13 risks should be part of developing risk algorithms combining maternal serum biochemistry and nuchal translucency for use in first trimester screening alongside those for trisomy 21 and trisomy 18.

Adult↗
PubMed2000

The influence of ethnic origin on first trimester biochemical markers of chromosomal abnormalities.

In a first trimester study of 5422 Caucasian women, 752 Afro-Caribbean women and 170 Asian women we have shown that the median maternal serum marker MoMs for free beta-hCG and PAPP-A were 19% and 48% higher in Afro-Caribbean women and 19% higher and 35% higher in Asian women, compared to Caucasian women. Correcting for maternal weight made very little difference to the effect in Afro-Caribbeans (21% and 57% higher after weight correction) but reduced the effect in Asians (4% and 17% higher after weight correction ). It is estimated that correcting for maternal weight and ethnicity overall would increase the detection rate by a modest 1.4%. However, the effect on an individual's risk could result in as much as a two-fold increase in the patient specific risk for trisomy 21. The impact of ethnic origin seems to be greater than that observed with second trimester biochemical markers and larger studies are required in order to develop robust algorithms for correcting for ethnic origin in the first trimester.

Africa↗
PubMed2000

Second-trimester prenatal screening for Down syndrome and the relationship of maternal serum biochemical markers to pregnancy complications with adverse outcome.

In a group of 26 524 control pregnancies and a group of 3728 pregnancies affected by one or more of the pregnancy complications of low birthweight, intra-uterine growth restriction (IUGR), preterm delivery and stillbirth, I have compared the relative risk of occurrence of these complications in pregnancies which had a raised maternal serum AFP (>2.0 MoM), raised maternal serum free beta-hCG (>2.0 MoM), low AFP (<0.5 MoM), low free beta-hCG (<0.5 MoM), combined raised AFP and free beta-hCG (>2.0 MoM), and in those with an increased Down syndrome risk (1 in 250 or greater). In the low birthweight group, only an increased AFP and decreased free beta-hCG showed significance with relative risks of 1.6 and 2.1. In the IUGR group, also only an increased AFP and decreased free beta-hCG showed significance with relative risks of 1.6 and 2.3. In the preterm delivery group, raised AFP, reduced free beta-hCG, and combined elevated AFP and free beta-hCG showed significance with relative risks of 3.8, 1.8 and 6.2. In the stillbirth group, raised AFP, reduced free beta-hCG, and combined elevated AFP and free beta-hCG showed significance with relative risks of 4.5, 2,4 and 7.2. An isolated raised free beta-hCG or an increased Down syndrome risk were not associated with an increased relative risk for any of the pregnancy complications investigated. However, apart from the six to seven-fold increased risk when both AFP and free beta-hCG are above 2.0 MoM, suggesting increased risk of preterm delivery or impending fetal death, the clinical utility of such significant differences is probably poor.

Adult↗
PubMed2000

The influence of fetal sex in screening for trisomy 21 by fetal nuchal translucency, maternal serum free beta-hCG and PAPP-A at 10-14 weeks of gestation.

In a study of 2923 normal pregnancies and 203 pregnancies affected by trisomy 21 we have shown a significant difference in the median MoM of the markers: fetal nuchal translucency, maternal serum free beta-hCG and PAPP-A in the presence of a female fetus compared with a male fetus. For maternal serum free beta-hCG levels are higher by 15% if the fetus is chromosomally normal and by 11% if the fetus has trisomy 21. For maternal serum PAPP-A the levels in chromosomally normal fetuses are 10% higher in the presence of a female fetus and 13% higher if the fetus has trisomy 21. In contrast, fetal nuchal translucency is 3-4% lower in both chromosomally normal and trisomy 21 female fetuses. The consequence of such changes when screening for trisomy 21 will be a reduction in the detection rate in female fetuses by a factor of 1-2%. Correction of risk algorithms for fetal sex, however, is probably not feasible, since ultrasound detection of fetal sex is only 70-90% accurate in the 10-14 week period.

Adult↗
PubMed2000

The influence of parity and gravidity on first trimester markers of chromosomal abnormality.

We have studied changes in first trimester fetal nuchal translucency (NT) and maternal serum free beta-hCG and PAPP-A with gravidity and parity in 3252 singleton pregnancies unaffected by chromosomal abnormality or major pregnancy complications. We have shown that gravidity and parity is associated with a small but progressive decrease in fetal NT and a small but progressive increase in free beta-hCG and PAPP-A. None of these small changes with increasing gravidity or parity are statistically significant and hence correction for these variables is not necessary when considering first trimester screening for chromosomal abnormalities.

Adult↗
PubMed1999

Screening for trisomy 18 by fetal nuchal translucency and maternal serum free beta-hCG and PAPP-A at 10-14 weeks of gestation.

In a study of 50 cases of trisomy 18 compared with 947 controls we have found the median multiple of the median (MoM) of maternal serum free beta human chorionic gonadotrophin to be significantly decreased (0.281 MoM) in samples collected between the 10th and 14th week of gestation. Similarly, maternal serum pregnancy associated plasma protein A (PAPP-A) levels are also decreased (0.177 MoM), whilst the median nuchal translucency is significantly higher (3.272 MoM). Free beta-hCG MoM was less than the 5th centile of normal in 64 per cent of cases of trisomy 18 and for PAPP-A was less than the 5th centile in 78 per cent of cases. Also, in 78 per cent of cases the nuchal translucency was above the 95th centile. When combined together in a multivariate algorithm with maternal age, we predict that 89 per cent of cases of trisomy 18 could be detected at a 1 per cent false-positive rate. We conclude that specific trisomy 18 risks should be part of developing risk algorithms combining maternal serum biochemistry and nuchal translucency for use in first trimester screening alongside those for trisomy 21.

Adolescent↗
PubMed1999

The influence of smoking on maternal serum PAPP-A and free beta hCG levels in the first trimester of pregnancy.

In an analysis of 3111 singleton pregnancies routinely screened in the first trimester with nuchal translucency, free beta hCG and pregnancy associated plasma protein A (PAPP-A) smoking has been found to occur in 20.8 per cent of pregnant women. When the individual marker levels were assessed in smokers and non-smokers, levels of PAPP-A were reduced in smokers by some 15 per cent. Despite free beta hCG levels being reduced by 10-14 per cent in the second trimester of smoking women, in the first trimester period this is not evident. Simulation studies would suggest that in smokers the detection of trisomy 21 using free beta hCG, PAPP-A and maternal age will be reduced by some 5 to 6 per cent compared with that of the general population.

Case-Control Studies↗
PubMed1999

Urine free beta-hCG and total estriol for Down syndrome screening during the second trimester in an Asian population.

OBJECTIVE: To evaluate second-trimester free beta-hCG and total estriol (E3) in the maternal urine as markers for Down syndrome screening in an Asian population. METHODS: Free beta-hCG and total E3 were measured in the urine samples of 28 Taiwanese Down syndrome pregnancies and 268 unaffected singleton pregnancies at 14-25 weeks. Results were normalized to urine creatinine concentrations and converted to multiples of the median (MoM) levels. Gestational ages were estimated by ultrasound measurements. RESULTS: Median values of free beta-hCG, total E3, free beta-hCG to total E3 ratio, and the free beta-hCG to total E3 MoM ratio in Down syndrome pregnancies were 4.75 MoM, 0.66 MoM, 8.99 MoM, and 9.51, respectively. At a 5% false-positive rate, the observed detection rates were 36% (ten of 28) with total E3, 71% (20 of 28) with free beta-hCG, 68% (19 of 28) with free beta-hCG/total E3, and 71% (20 of 28) with free beta-hCG/total E3 MoM. When combined with maternal age, the expected detection rates were 65% with total E3, 71% with free beta-hCG, 76% with free beta-hCG/total E3, 80% with free beta-hCG/total E3 MoM, and 89% when combining free beta-hCG, total E3, and maternal age. CONCLUSION: Urine free beta-hCG and total E3 are useful markers for Down syndrome screening during the second trimester in Taiwanese women.

Adult↗
PubMed1999

Calcified right atrial mass in a woman receiving long-term intravenous phosphate therapy.

Right atrial masses are easily seen by 2-dimensional echocardiography and may represent primary tumors, secondary tumor invasion of the right atrium, tricuspid valve vegetations, or atrial thrombi. Calcification of right atrial masses is uncommon but easily identified by 2-dimensional echocardiography because of the high echogenicity of calcium deposits. We describe a patient with a heavily calcified right atrial thrombus caused by an indwelling central venous catheter and long-term intravenous phosphate infusion.

Calcinosis↗
PubMed1999

Activation of alcohol-related associative networks by recent alcohol consumption and alcohol-related cues.

AIMS: To investigate the influence of recent alcohol consumption and alcohol-related cues on performance in a sentence generation task. DESIGN: Two experiments were carried out. In the first, the performances of light, moderate and heavy drinkers were compared. In the second, subjects were randomly assigned to one of three experimental treatments (alcohol-priming, non-alcohol priming, and control) and classified as light, moderate or heavy drinkers. The effect of experimental treatment, drinking status, gender and the interaction between these factors was studied. SETTING: The experiments were carried out in quiet research rooms in psychology departments. PARTICIPANTS: Volunteers recruited from university campuses. MEASUREMENTS: Questionnaires were used to ascertain recent drinking histories. Subjects generated sentences incorporating ambiguous alcohol-related words which were provided by the experimenter. The sentences were then classified as alcohol-related or not, the dependent measure was the number of alcohol-related sentences produced. FINDINGS: In both experiments heavier drinkers produced more alcohol-related sentences and males produced more alcohol-related sentences than females. In the second experiment more alcohol-related sentences were produced after subjects were exposed the alcohol priming condition. CONCLUSIONS: The alcohol-related meaning of ambiguous words is more likely to be accessed by males and by heavier drinkers and after exposure to other alcohol cues.

Adult↗
PubMed1999

A screening program for trisomy 21 at 10-14 weeks using fetal nuchal translucency, maternal serum free beta-human chorionic gonadotropin and pregnancy-associated plasma protein-A.

OBJECTIVE: To examine the potential impact of combining maternal age with fetal nuchal translucency thickness and maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) in screening for trisomy 21 at 10-14 weeks of gestation. METHODS: Maternal serum free beta-hCG and PAPP-A were measured by Kryptor, a random access immunoassay analyzer using time-resolved amplified cryptate emission, in 210 singleton pregnancies with trisomy 21 and 946 chromosomally normal controls, matched for maternal age, gestation and sample storage time. In all cases the fetal crown-rump length and nuchal translucency thickness had been measured by ultrasonography at 10-14 weeks of gestation and maternal blood had been obtained at the time of the scan. The distributions (in multiples of the median; MoM) of free beta-hCG and PAPP-A (corrected for maternal weight) and fetal nuchal translucency (NT) were determined in the trisomy 21 group and the controls. Likelihood ratios for the various marker combinations were calculated and these were used together with the age-related risk for trisomy 21 in the first trimester to calculate the expected detection rate of affected pregnancies, at a fixed false-positive rate, in a population with the maternal age distribution of pregnancies in England and Wales. RESULTS: In a population with the maternal age distribution of pregnancies in England and Wales, it was estimated that, using the combination of maternal age, fetal nuchal translucency thickness and maternal serum free beta-hCG and PAPP-A, the detection of trisomy 21 pregnancies would be 89% at a fixed false-positive rate of 5%. Alternatively, at a fixed detection rate of 70%, the false-positive rate would be 1%. The inclusion of biochemical parameters added an additional 16% to the detection rate obtained using NT and maternal age alone. CONCLUSIONS: Rapid diagnostic technology like Kryptor, which can provide automated reproducible biochemical measurements within 30 min of obtaining a blood sample, will allow the development of interdisciplinary one-stop clinics for early fetal assessment. Such clinics will be able to deliver improved screening sensitivity, rapidly and more efficiently, leading to reduced patient anxiety and stress.

Adolescent↗
PubMed1999

Second-trimester maternal urine human chorionic gonadotrophin beta-core fragment concentrations in Asian pregnancies with fetal chromosomal abnormalities.

The aim of this study was to investigate the second trimester concentrations of maternal urine human chorionic gonadotrophin beta-core fragment (HCGbetacf) in Asian pregnanci2es with fetal chromosomal abnormalities. HCGbetacf concentrations were analysed from 34 urine samples in chromosomally abnormal pregnancies, including 28 cases of Down's syndrome, one case of trisomy 18, and five cases of other chromosomal abnormalities (one mosaic deletion and four translocations), and in a cohort of 268 normal pregnancies receiving second trimester amniocentesis. Results were normalized to urine creatinine (Cr) concentration and converted to the multiple of the median (MOM) concentration for the appropriate gestation. The median HCGbetacf MOM concentrations of Down's syndrome pregnancies (12.89) was significantly higher than that of normal pregnancies (1. 06) (P < 0.00001). Wide variations of HCGbetacf concentrations were observed in other chromosomally abnormal pregnancies. There were 18 of 28 (64%) Down's syndrome cases but one of five (20%) other chromosomally abnormal cases with HCGbetacf concentrations above the 95th centile of the control values (8.22 MOM cut-off). These findings suggest that HCGbetacf could be a potential marker in urine screening for fetal Down's syndrome in Asians.

Adult↗
PubMed1999

Second trimester prenatal screening for Down's syndrome using alpha-fetoprotein and free beta hCG: a seven year review.

OBJECTIVE: To determine the value and impact over a seven year period of a second trimester screening programme for trisomy 21 and trisomy 18, using the two maternal serum markers alpha-fetoprotein and free beta human chorionic gonadotrophin. DESIGN: Retrospective review. SETTING: A biochemical screening laboratory serving three health districts with three antenatal clinics in both teaching and nonteaching hospitals. POPULATION: 67,904 pregnancies in women of all ages screened between 14 and 22 weeks of gestation between 1 April 1991 and 31 March 1998. METHODS: All women booked into three major antenatal clinics were offered biochemical screening. Women at increased risk of trisomy 21 or trisomy 18 (> or =1 in 250 at term) were offered an invasive diagnostic procedure. Follow up of the outcome of all pregnancies was performed. MAIN OUTCOME MEASURES: Detection rate for trisomy 21 and trisomy 18, false positive rates, uptake of screening, uptake of amniocentesis in women identified at increased risk, prevalence of trisomy 21 at birth, detection and false positive rates by maternal age, fetal loss rate after amniocentesis, report turn around time, and identification of other anomalies. RESULTS: Overall, 87% (67,904/78,501) of women underwent screening. The rate of detection of trisomy 21 was 75% (80/107; 95% CI 66 to 83) with a 5.1% false positive rate (3466/67,904; CI 4.9 to 5.3%). In women under 30 years of age the detection rate was 60% (18/30; CI 41 to 77) with a 2.6% false positive rate (956/36,371; CI 2.5 to 2.8). The rate of detection of trisomy 18 was 57% (8/14; CI 29 to 82) with a 0.7% false positive rate (475/67,904; CI 0.64 to 0.76). Uptake of amniocentesis was 83% (2912/3508). Women were 3.3 times more likely to refuse amniocentesis if the risk was close to the cutoff (1 in 250) than if the risk was > or =1 in 50. Fetal loss within 28 days of amniocentesis was 0.9% (25/2912). Prenatal screening identified 84 other anomalies in addition to 41 cases of impending fetal death. CONCLUSION: Second trimester prenatal screening for trisomy 21 and trisomy 18 using a simple two marker approach incorporating free beta hCG can achieve high detection rates over a long period of time. Health authorities who still have not introduced trisomy 21 screening should be encouraged by what can be achieved and should consider making such screening available to all women. Established second trimester detection rates of 75% for a 5% false positive rate will be the benchmark by which first trimester screening using nuchal translucency, PAPP-A and free beta hCG will be judged.

Adult↗