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Biomedical subjects

A C Ravelli

Publications and source records attributed to A C Ravelli.

28 records · Page 2Linked to original sources
PubMed1996

Biplane transesophageal color-flow Doppler imaging in assessing severity of mitral regurgitation: influence of hemodynamic circumstances and mechanism of regurgitation.

OBJECTIVE: To determine the value of biplane transesophageal echocardiography in the assessment of severity of mitral regurgitation compared with left ventricular angiography. DESIGN: Prospective study of consecutive patients. SETTING: Two university hospitals, one community hospital. PARTICIPANTS: Thirty-seven patients with angiographically proven mitral regurgitation. INTERVENTION: Transthoracic and biplane transesophageal echocardiography. In 19 patients, transesophageal echocardiography was performed during general anesthesia. MEASUREMENTS AND MAIN RESULTS: The largest mitral regurgitation jet area and longest jet as obtained with Doppler color-flow mapping from transthoracic and biplane transesophageal echocardiography and pulsed-Doppler pulmonary venous flow characteristics. Sensitivity and 100-minus-specificity were plotted to constitute receiver operating characteristics (ROC) curves. Areas under ROC curve for transverse, longitudinal, and biplane jet area were 0.77, 0.75, and 0.81, and for jet length, 0.82, 0.84, and 0.88, respectively; this was for biplane jet area in conscious patients; 0.99 compared with 0.72 in anesthetized patients (p < 0.05). CONCLUSIONS: Biplane measurements identified severe mitral regurgitation slightly more reliably than the transverse or longitudinal measurements alone. In conscious patients, jet area was an excellent test for estimating severity of mitral regurgitation. In anesthetized patients, a combination of biplane jet area and length and of systolic pulmonary venous flow reversal accurately predicted angiographic severity of mitral regurgitation. In anesthetized patients, the optimal cut-off value for jet area to distinguish between moderate and severe mitral regurgitation was lower than in conscious patients. In the total population, regardless of hemodynamic and technical variations, a combination of biplane jet area and length and of systolic pulmonary venous flow reversal accurately predicted the severity of mitral regurgitation.

Adult↗
PubMed1996

The indirect association of lactation with subsequent perimenopausal body weight.

OBJECTIVE: We aimed to estimate the relationship of prior breastfeeding to perimenopausal body mass index (BMI) (kg/m2). While most long-term studies of women's body weight after reproductive experience have found a negative relationship between lactation and body weight, most short-term studies found either no impact of lactation on body weight, or decelerated postpartum weight loss among breastfeeding women. DESIGN: We performed a retrospective cohort study. SETTING: The study was done in The Netherlands between 1987 and 1990. SUBJECTS: The 1067 singleton females who were born around the time of the Dutch famine (1 August 1944 through 15 April 1946) at The University of Amsterdam Teaching Hospital were all traced and accounted for. This analysis refers to the 671 who were interviewed and for whom all data elements were available. ANALYSIS: We related parity and number of children breastfed at least 1 week to BMI at age 45 and at the time of marriage, both calculated from respondents: recall of weight and height, by linear multiple regression analysis, adjusting for potentially confounding variables. RESULTS: Among parous women, each additional live birth was associated with a BMI increase of 0.69 kg/m2 (CI = 0.24 to 1.13, P = 0.003), and for each additional child breastfed, the BMI was lower by 0.41 kg m2 (CI = -0.77 to -0.04, P = 0.03) at age 45. However, BMI before any reproductive experience was 0.39 kg/m2 greater (CI = 0.08 to 0.71, P = 0.01) with each additional subsequent birth, and for each additional infant breastfed, 0.34 kg/m2 lower (CI = - 0.60 to - 0.09, P = 0.008). CONCLUSIONS: The negative relationship of prior breastfeeding to perimenopausal weight was probably not causally related to breastfeeding, since the relationship was present before any reproductive experience. The results could also arisen in part because of biased recall of weight; however, the relationship of parity to perimenopausal BMI was far less attenuated by adjusting for prior BMI than was the association with breastfeeding, lending support to an indirect association of breast- feeding with later BMI.

Bias↗
PubMed1995

Additional value of biplane transesophageal echocardiography in assessing the genesis of mitral regurgitation and the feasibility of valve repair.

To determine the additional diagnostic value of biplane transesophageal echocardiography (TEE) in patients undergoing mitral valve surgery, we studied 48 patients with severe mitral regurgitation. Transesophageal echocardiographic video recordings were reorganized in separate transverse and longitudinal sections to allow independent evaluation. Mechanism of mitral regurgitation and anatomic abnormalities of the mitral valve were assessed by all 3 transesophageal echocardiographic modalities and were related to surgical findings. Biplane TEE detected increased leaflet mobility with a sensitivity of 91% and a specificity of 84%, and restricted leaflet mobility with a sensitivity of 100% and a specificity of 97%. Biplane TEE was accurate in the diagnosis of most of the anatomic abnormalities associated with these mechanisms. However, the sensitivity for detecting subvalvular abnormalities (including papillary muscle abnormalities) was poor, and measurement of the annular diameter had a poor correlation with annular dilatation. Although the yield of biplane TEE was better than either transverse or longitudinal TEE alone, the differences did not reach statistical significance, because of the size of the patient group. The surgical procedure (either valve repair or replacement) was correctly predicted with transverse TEE in 71%, with longitudinal TEE in 69%, and with biplane TEE in 79% of the patients. All 3 transesophageal echocardiographic modalities are very capable of assessing the anatomic abnormalities and mechanism of mitral regurgitation, as well as predicting the feasibility of valve repair.

Aged↗
PubMed1995

Timing of prenatal starvation in women and birth weight in their first and second born offspring: the Dutch Famine Birth Cohort study.

OBJECTIVES: To examine the long-term effects of severe in utero maternal undernutrition on offspring birth weight. STUDY DESIGN: Birth weights were analyzed of 575 first born and 454 second born offspring of 683 women born in Amsterdam, the Netherlands, at the time of a severe famine at the end of World War II. In utero maternal undernutrition was defined separately for each pregnancy trimester by an average daily nutrition ration (supplied to the grandmother) of less than 1000 calories in that trimester of pregnancy. RESULTS: Compared to controls, birth weights of first born infants of women prenatally exposed in the first trimester of pregnancy were 73 g heavier (95% CI: -64, 210), and birth weights of second born infants were 96 g lighter (95% CI: -249, 58). Birth weights of infants of women exposed in the second or third trimester were much closer to controls. CONCLUSIONS: A substantial (200 g or more) impact of severe in utero maternal undernutrition on OBW can be ruled out. There may, however, be parity specific, moderate (50-100 g) effects of maternal undernutrition early in pregnancy on OBW. This suggestion requires confirmation in other populations.

Adult↗
PubMed1995

Famine, third-trimester pregnancy weight gain, and intrauterine growth: the Dutch Famine Birth Cohort Study.

Data from the Dutch Famine Birth Cohort Study were analyzed to assess the influence of acute famine on the relation of maternal weight gain to birth weight, length, and ponderal index. Records were examined for 734 women receiving at least one month of prenatal care and delivering live-born singleton females at the University of Amsterdam Teaching Hospital between August 1944 and April 1946. This period preceded, encompassed, and followed the Hunger Winter, a severe famine. After adjusting for covariates, weight loss or low to moderate (< or = 0.5 kg/week) weight gain was strongly associated with (p < 0.001 for each model) with offspring birth weight, length, and ponderal index and with trimester of famine exposure. At weight gains greater than 0.5 kg/week further weight gain was not associated with birth size. Among women losing weight or gaining < or = 0.5 kg/week the association between third-trimester weight change and birth weight among mother-daughter pairs exposed to famine in early or mid-pregnancy was stronger than the association observed among the unexposed cohort or among those exposed only late in pregnancy. Our results suggest that acute maternal nutritional deprivation affects fetal growth only below a threshold and that, conversely, even after a famine period offspring birth size does not respond in a linear fashion to ad libitum maternal feeding.

Adult↗
PubMed1994

Maternal recall of birthweights of adult children: validation by hospital and well baby clinic records.

BACKGROUND: Several studies have suggested that maternal recall of offspring birthweight compares well to data from birth certificates or medical records. However, these studies describe relatively short recall periods and pertain to populations where hospitalized childbirth is the norm. Accuracy of maternal recall has not been confirmed after long recall periods or in populations where non-hospitalized childbirth is common. METHODS: Accuracy of recalled birthweights is assessed among 626 women interviewed at an average age of 43.3 years (standard deviation [SD] 1 year), at which time the average age of their 1297 offspring was 17.9 years (range 1-29 years, SD 4.8 years). One-third of these infants were delivered at home. Recalled birthweight was compared to hospital or Well Baby clinic records, available for 66% (861/1297) of all births. RESULTS: Record availability was not related to birthweight. For the 861 infants for whom both sources were available mean recorded birthweight was 3342 g (SD 586 g) and mean recalled birthweight 3340 g (SD 675 g). Recalled weights overestimated recorded weights by 109 g (95% Cl: 68-151) among infants weighing > 3750 g and underestimated recorded weights by 83 g (95% Cl: 54-111) among infants weighing < or = 3250 g. CONCLUSIONS: As an outcome variable recalled birthweights were unbiased, but less precise than recorded birthweights. Use of recalled birthweight does not sacrifice study power however and may increase generalizability provided recalled weights are available for 30% more infants than recorded weights. For individual birthweight assessment and for use as an independent variable recalled weights are biased and may have to be adjusted using recorded data as available.

Adult↗
PubMed1993

The Dutch famine birth cohort study: design, validation of exposure, and selected characteristics of subjects after 43 years follow-up.

A historical birth cohort study of 1116 women born between August 1 1944 and April 15 1946 in the Wilhelmina Gasthuis hospital in Amsterdam, the Netherlands, was set up to study the short- and long-term effects of a limited period of extreme nutritional deprivation in the winter of 1944-1945 in the Western Netherlands. The degree of food deprivation is evidenced by a dramatic decline in third trimester pregnancy weight gain and infant birthweight. All women were traced and 84% (683/813) of survivors presently resident in the Netherlands agreed to be interviewed in their homes. There were no differences in characteristics at birth between interviewed and uninterviewed survivors. The women who were interviewed had 1299 offspring and were able to recall birthweight of all of them. Additional birthweight information from hospital and well-baby clinic (WBC) records is available for about half of the offspring. Since the famine was imposed on the entire population of a well-defined area, whose opportunities to obtain food elsewhere were severely restricted, and the women from this hospital cohort were predominantly lower middle class, the relationship between fetal nutrition and subsequent health outcomes in this cohort is not likely to be confounded by unmeasured attributes related to social class. In addition, selective losses to follow-up could be excluded, which makes the Dutch famine birth cohort a valuable resource for future studies in perinatal epidemiology.

Adult↗
PubMed1991

A physical activity questionnaire for the elderly.

A validated physical activity questionnaire for young adults was adapted and validated for use in free living, apparently healthy people, aged 63-80 yr. Test-retest reliability of the questionnaire on 29 participants was 0.89 as determined by Spearman's correlation coefficient. Further classification by tertiles of activity resulted in 72% of the participants being correctly classified and 0% grossly misclassified on two separate occasions. In a similar group of 31 subjects, classifications based on questionnaire activity scores were compared with classifications obtained by repeated 24-h activity recalls and pedometer measurements, showing Spearman's correlations of 0.78 and 0.73, for both methods, respectively. Seventy-one and 67% of the subjects, respectively, were classified in the same activity tertile for both methods. It is concluded that the questionnaire provides a reliable and valid method for classifying elderly subjects into categories of high, medium, and low physical activity.

Activities of Daily Living↗
PubMedDate not supplied

A time series analysis of sulphur dioxide, temperature, and influenza incidence in 1976-1987.

Patterns in the occurrence of influenza-like symptoms after increases in ambient sulphur dioxide (SO2) concentrations, have been investigated. Three routinely collected sets of data were used: (a) air pollution, including SO2, as measured continuously by the National Air Monitoring System; (b) ambient outdoor air temperature as measured hourly by the Royal Dutch Meteorological Institute and (c) weekly influenza incidence as monitored by the Dutch Sentinel Practice Network. The region investigated has been confined to the three western provinces of the Netherlands. The data were expressed as weekly average values. To correct for autocorrelation the 'Box-Jenkins approach' to model time series was used. After correction for seasonal patterns and a log transformation the ARMA (autoregressive and moving average) models were identified. The relation between the time series has been assessed by a transfer function model. After correction for temperature and with a delay of two weeks, a significant association could be ascertained between the hourly SO2 concentration and influenza incidence. An association between lower temperature and increased influenza incidence one week later was established as well. A relation of air pollution and influenza with a delay of about two weeks is quite possible. However, 12 years may have been too short a period to correct for secular patterns and SO2 was probably only an indicator of air pollution. Further investigation seems warranted.

Air Pollutants↗