Jaundice occurs in most newborn infants. Most jaundice is benign, but because of the potential toxicity of bilirubin, newborn infants must be monitored to identify those who might develop severe hyperbilirubinemia and, in rare cases, acute bilirubin encephalopathy or kernicterus. The focus of this guideline is to reduce the incidence of severe hyperbilirubinemia and bilirubin encephalopathy while minimizing the risks of unintended harm such as maternal anxiety, decreased breastfeeding, and unnecessary costs or treatment. Although kernicterus should almost always be preventable, cases continue to occur. These guidelines provide a framework for the prevention and management of hyperbilirubinemia in newborn infants of 35 or more weeks of gestation. In every infant, we recommend that clinicians 1) promote and support successful breastfeeding; 2) perform a systematic assessment before discharge for the risk of severe hyperbilirubinemia; 3) provide early and focused follow-up based on the risk assessment; and 4) when indicated, treat newborns with phototherapy or exchange transfusion to prevent the development of severe hyperbilirubinemia and, possibly, bilirubin encephalopathy (kernicterus).

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Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation

Preface to the Paperback Edition. Preface. About the Author. 1. Overview and Background. 2. Basic Concepts and Distributions for Product Life. 3. Probability Plotting of Complete and Singly Censored Data. 4. Graphical Analysis of Multiply Censored Data. 5. Series Systems and Competing Risks. 6. Analysis of Complete Data. 7. Linear Methods for Singly Censored Data. 8. Maximum Likelihood Analysis of Multiply Censored Data. 9. Analyses of Inspection Data (Qualtal--Response and Interval Data). 10. Comparisons (Hypothesis Tests) For Complete Data. 11. Comparisons with Linear Estimators (Singly Censored and Complete Data). 12. Maximum Likelihood Comparisons (Multiply Censored and Other Data). 13. Survey of Other Topics. Appendix A. Tables. References. Index.

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Applied life data analysis

Bandit processes and dynamic allocation indices

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Bandit Processes and Dynamic Allocation Indices

Cytochrome P450 enzymes that metabolize estrogens are expressed in the mammary gland, uterus, brain and other target tissues for estrogen action, and this results in the formation of hydroxylated estrogens in these tissues. Estradiol metabolites formed in target tissues at or near estrogen receptors may either be inactive or have important biological effects, and changes in the activities of estrogen-metabolizing enzymes in target tissues may profoundly influence estrogen action. Although some active estrogen metabolites exert hormonal effects in target tissues by interaction with the classical estrogen receptor, other metabolites appear to elicit unique biological responses that are not associated with activation of this receptor. Therefore, some of the many actions of estradiol may not be caused by estradiol per se, but may result from the formation of active estrogen metabolite(s) which function as local mediators or may activate their own unique receptors or effectors. This is an important area in need of more research. The present paper represents a review of the literature and perspectives by the authors on the functional role of estrogen metabolism in target tissues.

https://www.hormonebalance.org/images/documents/Zhu%2098estrogen%20metabolism%20in%20target%20cells%20Carc.pdf

Functional role of estrogen metabolism in target cells: review and perspectives.

The log-normal and the Weibull are often considered for situations in which a skewed distribution for a non-negative random variable is needed. The ratio of maximized likelihoods provides a good test for selecting one of these. A table of the necesqary critical values is given. The table may also be used for discriminnting between the normal and the type 1 extreme value distributions.

Discrimination Between the Log-Normal and the Weibull Distributions

Aromatase activity was measured in 104 primary and 24 metastatic breast cancer patients. The assay employed quantitates the production of 3H water release from 1β-[3H] androstenedione after aromatization. Of 104 human primary breast tumors studied, 64 contained measurable aromatase activity, ranging from 5–70.5 pmol estrone formed/g protein/hour. In primary breast cancers there was no difference in levels of aromatase activity when analyzed by menstrual status or age by decade. Aromatase activity was similar in small and large primary tumors. The median aromatase activity of primary breast tumors (8.6 pmol/g/h) was similar to that found in metastatic breast cancer deposits (12.0 pmol/g/h). Aromatase activity did not correlate with either estrogen (ER) or progesterone (PR) receptor concentration in the tissues assayed. In this regard there were 33 ER− PR− tumor biopsies. Twelve of these 33 tumors contained aromatase activity greater than 10 pmol/g/hour. Cancer 59:779-782, 1987.

Aromatase activity in primary and metastatic human breast cancer

We measured the serum bilirubin concentrations in 2,416 consecutive infants admitted to our well baby nursery. The maximal serum bilirubin concentration exceeded 12.9 mg/dL (221 mumol/L) in 147 infants (6.1%), and these infants were compared with 147 randomly selected control infants with maximal serum bilirubin levels less than or equal to 12.9 mg/dL. A serum bilirubin concentration greater than 12.9 mg/dL was associated strongly with breast-feeding (P = .0000) and percentage of weight loss after birth (P = .0001), as well as with maternal diabetes, oriental race, decreased gestational age, male sex, bruising, and induction of labor with oxytocin. Risk ratios and the risk of jaundice were calculated for hypothetical infants in the presence and absence of these variables. These calculations show that, in certain infants, "nonphysiologic" jaundice is likely to develop and its presence in such infants might not require laboratory investigations. In others, a modest degree of hyperbilirubinemia could be cause for concern. An awareness of these factors and their potential contribution to serum bilirubin levels permits a more rational approach to the action levels used for the investigation of jaundice in the newborn. We need a new definition of physiologic jaundice.

Jaundice in the Healthy Newborn Infant: A New Approach to an Old Problem

Some of the questions concerning the uniqueness of the maximum likelihood estimates for the parameters in the Weibull distribution are considered for both censored and noncensored samples. In some cases answers previously known are reviewed, while new results are presented for some other cases. In particular, it is shown that with the shape parameter known, the maximum likelihood estimates of the location and scale parameters exist and are unique. Also, the case in which all three parameters are unknown is examined in detail.

Maximum Likelihood Estimation with the Weibull Model

The problem of selecting a model from two models with unknown location and scale parameters is considered. It is noted that the distribution of the ratio of maximum likelihoods does not depend upon the values of the nuisance location and scale parameters. Consequently, this ratio provides a convenient (and hopefully powerful) test for discriminating between two location and scale parameter models when the parameters are unknown. Tables for discriminating between the normal and the Cauchy; the normal and the exponential; or the normal and the double exponential are presented. An empirical comparison of the power of this test with the power of the UMP invariant test for discriminating between the normal and the Cauchy is given. Some further comparisons with the chi-square goodness of fit and the Kolmogorov-Smirnov tests for normality are also given.

Charles E. Antle

Papers

Discrimination Between the Log-Normal and the Weibull Distributions

Aromatase activity in primary and metastatic human breast cancer

Jaundice in the Healthy Newborn Infant: A New Approach to an Old Problem

Maximum Likelihood Estimation with the Weibull Model

Likelihood Ratio Test for DiscriminaGon Between Two Models with Unknown Location and Scale Parameters