Comparison of infrared spectroscopic and fluorescence depolarization assays for fetal lung maturity.

OBJECTIVE: Infrared spectroscopic analysis of amniotic fluid was recently shown to be a potential useful method for the determination of fetal lung maturity. Those studies used thin-layer chromatography as a reference method for the calibration of the infrared-based technique. However, thin-layer chromatography is compromised by large intra-assay and interlaboratory coefficients of variation. Therefore in this study we have used a reference method that is based on fluorescence depolarization, the TDx FLM II assay, to verify the sensitivity and precision of infrared spectroscopy for assessment of fetal lung maturity status. STUDY DESIGN: Samples of amniotic fluid were obtained by amniocentesis from 101 patients between the 24th and 40th weeks of pregnancy. Small volumes (35 microL) of amniotic fluid specimens were dried, and the infrared spectra were measured with a commercial infrared spectrometer. The fetal lung surfactant/albumin ratio was determined separately for each specimen with the TDx FLM II assay. The proposed infrared method was then calibrated and tested with a partial least-squares regression analysis to quantitatively correlate the infrared spectra with the surfactant/albumin ratios provided by the TDx FLM II assays. RESULTS: A total of 144 training spectra were used to build the partial least-squares calibration model. The correlation coefficient for the training set was excellent (r = 0.92), with an SE between infrared-predicted and reference surfactant/albumin ratios of 17 mg/g. The model was then validated on a set of 69 test spectra and yielded an SE of 14 mg/g (r = 0.86). The final partial least-squares model included the 900- to 1500-cm(-1) and 2800- to 3200-cm(-1) spectral ranges and 6 partial least-squares factors. CONCLUSION: Because the infrared-based fetal lung maturity measurements correlated well with assays from both of the current standard clinical techniques (thin-layer chromatography and fluorescence depolarization) and the procedure is less labor and training intensive, we concluded that infrared spectroscopy has the potential to emerge as the method of choice for prediction of fetal lung maturity from amniotic fluid analysis.

Infrared spectroscopy of exfoliated cervical cell specimens. Proceed with caution.

OBJECTIVE: To determine whether diagnostic information may be recovered from the infrared spectra of exfoliated cell specimens by using a novel spectral feature extraction method, in conjunction with linear and quadratic discriminant analysis, for spectral classification. STUDY DESIGN: Over 800 infrared spectra were included in the study, with corresponding clinical diagnoses based upon cytology and, when available, histology reports. Three sets of classification trials were carried out with the aim of distinguishing the spectra corresponding to normal specimens from CIN 1, 2 and 3. For each of these three cases, the procedure was to: (1) develop a set of provisional classification models using only a "training" subset of the spectra, and (2) test each provisional model by its ability to correctly predict the diagnoses on the basis of the remaining spectra. RESULTS: For optimal classification trials, training set classification accuracies were 68% for normal/CIN 1, 73% for normal/CIN 2 and 81% for normal/CIN 3; for the corresponding test sets the classification accuracies were 60%, 60% and 67%, respectively. CONCLUSION: The infrared spectra of exfoliated cervical cells carry information regarding the presence or absence of dysplasia, and that information is recoverable--albeit imperfectly at this stage--from the spectra of "real life" cell preparations.

Determinants of fertility in Malaysia -- how much do we know?

PIP: Chinese and Indian fertility have continued to decline in the 1980s while Malay fertility has stabilized and even risen slightly. The objective of this literature review is to examine the literature on the role of socioeconomic determinants of family formation and childbearing when there are ethnic compositional differences and to examine the evidence for and explanation of why there are different ethnic responses to different socioeconomic variables. Recent fertility trends are identified. Fertility was high in 1957 among all ethnic groups, and Malay fertility was lowest. Chinese fertility declined first in the early 1960s. Malay fertility began its decline after 1964. Indian fertility did not fall until the late 1960s but was the most rapid. In 1966, the National Family Planning Program was initiated and targets were set for 2% growth by 1985. During the 1970s the proportion of Malay acceptors increased, but 10 years later the proportion using efficient methods of contraception declined. In the review of studies on socioeconomic determinants of fertility, women's education is usually associated negatively with family size through delayed age at first marriage, but the effects may vary within ethnic groups. Stronger associations between education and fertility are found for urban and rural Chinese and urban Indians, but socioeconomic factors such as husband's education and family income replace education in importance. The effect of education on family planning and contraceptive usage is more consistent across ethnic groups. Female employment, income, urbanization, migration, infant mortality, and other socioeconomic factors and their association with fertility are also reviewed. Ethnicity affects method of use, as does religion. Malays desire larger families, marry at earlier ages, and are less likely to use contraception which cannot be explained by compositional effects, and are weakly explained by cultural factors. The rise in Malay fertility may be explained by the government assistance from the New Economic Policy, a rise in religiosity, and pronatalist government policy. With a deep recession since 1985, the question remains as to the future effects on Malay fertility.^ieng