Revisiting the low birthweight paradox using sibling data with implications for the classification of low birthweight

Background

We examined the birthweight threshold for increased odds of neonatal death among second births based on their elder sibling's birthweight category.

Methods

This population-based cohort study included 190 575 women who delivered their first two non-anomalous singleton live births in Missouri (1989-2005). We examined the birthweight distribution and neonatal mortality curves of second births whose elder sibling had low versus adequate/high birthweight. We determined the optimal cut-off point for the classification of low birthweight among infants in each group based on the Youden index.

Results

Infants whose elder sibling had low birthweight had a lower mean birthweight and a higher percentage of low birthweight infants versus those whose elder sibling had adequate/high birthweight, but low birthweight infants in the former group had a lower rate of neonatal mortality. Upon standardizing the birthweight distribution to a Z-scale, neonatal mortality rates became comparable between the two groups at every rescaled birthweight for Z-scores ≥-3.7. The optimal cut-off point for low birthweight was 2500 and 3000 g among infants whose elder sibling had low and adequate/high birthweight, respectively.

Conclusions

Using sibling data for the classification of LBW may enable the identification of average-sized infants who may be at increased risk of neonatal mortality.

Assessing the utility of preoperative serum thyroglobulin in differentiated thyroid cancer: a retrospective cohort study

PURPOSE

Serum thyroglobulin (TG) is used to monitor for recurrence or progression of differentiated thyroid cancer (DTC). The role of preoperative TG measurement is more ambiguous, yet still being used in some centers. We aimed to determine whether preoperative TG correlates with disease stage or metastatic burden.

METHODS

A retrospective review of patients with TG measured before thyroidectomy was conducted. Data collected included demographics, preoperative TG, pathology, and cancer stage. Associations between preoperative TG levels and size of largest malignant nodule, thyroid gland size, stage of cancer, and presence of metastasis using Wilcoxon rank sum tests and Spearman correlations were performed. Receiver operator curve (ROC) was generated for metastasis status.

RESULTS

Of 598 patients, we excluded those with positive TG antibodies (n = 176); 422 patients were included in the final analysis. Median age was 55 years and 76% were female. Of 78% with malignancy, papillary thyroid cancer was the most frequent (92%). 18% had TG levels >500 ng/mL and 29% <45 ng/mL. 4% had distant metastasis and 18% had lymph node metastasis. Median follow-up was 52 months. Significant positive correlations between preoperative TG and thyroid size (rho 0.49, p < 0.001), and malignant nodule size (rho 0.27, p < 0.001). Using a cut-off of 500 ng/mL, sensitivity to detect metastasis was 10.3% (95% CI 2.5-18.2), specificity 90.0% (95% CI 86.0-93.9). The area under curve for ROC (0.46, 95% CI 0.38-0.54) indicated poor diagnostic ability for metastasis.

CONCLUSION

Although preoperative TG correlated significantly with the size of the gland and T stage, there was no correlation with metastasis. Preoperative TG is of limited utility in today's value-based healthcare environment.

Racial/Ethnic Differences in Correlates of Spontaneous and Medically-Indicated Late Preterm Births among Adolescents

STUDY OBJECTIVE

To investigate the racial/ethnic differences in the correlates of spontaneous and medically-indicated late preterm birth (LPTB), defined as deliveries between 34 0/7 and 36 6/7 weeks gestation, among US adolescents.

DESIGN

Population-based, retrospective cohort study.

SETTING

Births in the United States to adolescents in 2012.

PARTICIPANTS

Adolescents (younger than 20 years; n = 171,573) who delivered nonanomalous singleton first births between 34 and 44 weeks of gestation.

INTERVENTIONS AND MAIN OUTCOME MEASURES

Bivariate and multivariable logistic regression were used to evaluate the associations between maternal risk factors and spontaneous and medically-indicated LPTB, stratified according to maternal race/ethnicity.

RESULTS

Risk factors for spontaneous LPTB included single marital status among Asian adolescents; no insurance coverage among whites, Asian, and Hispanic adolescents; inadequate prenatal care among all racial/ethnic groups except American Indian, and adequate plus prenatal care among all races/ethnicities; prenatal smoking among whites and black adolescents; insufficient gestational weight gain among all racial/ethnic groups except American Indian; and prepregnancy underweight among white, black, and Hispanic adolescents. Risk factors for medically-indicated LPTB included inadequate prenatal care among white, black, and Hispanic adolescents, and adequate plus prenatal care among all racial/ethnic groups except Asian; insufficient gestational weight gain among white, black, and Hispanic adolescents; and prepregnancy overweight and obesity among white, black, and Hispanic adolescents.

CONCLUSION

Our results show racial/ethnic differences in the correlates of spontaneous and medically-indicated LPTB among US adolescents and support the need for risk-specific interventions among different racial/ethnic groups.

Isolation and characterization of human monoclonal antibodies to digoxin

Fab preparations of sheep polyclonal anti-digoxin Abs have proven useful for reversal of the toxic effects of digoxin overdoses in patients. Unfortunately, the use of foreign species proteins in humans is limited because of the potential for immunological responses that include hypersensitivity reactions and acute anaphylaxis. Immunization of recently developed transgenic mice, whose endogenous micro heavy and kappa light chain Ig genes are inactivated and which carry human Ig gene segments, with a digoxin-protein conjugate has enabled us to generate and isolate eight hybridoma cell lines secreting human sequence anti-digoxin mAbs. Six of the mAbs have been partially characterized and shown to have high specificity and low nanomolar affinities for digoxin. In addition, detailed competition binding studies performed with three of these mAbs have shown them to have distinct differences in their digoxin binding, and that all three structural moieties of the drug, the primary digitoxose sugar, steroid, and five-member unsaturated lactone ring, contribute to Ab recognition.

Isolation and Characterization of Human Monoclonal Antibodies to Digoxin

Fab preparations of sheep polyclonal anti-digoxin Abs have proven useful for reversal of the toxic effects of digoxin overdoses in patients. Unfortunately, the use of foreign species proteins in humans is limited because of the potential for immunological responses that include hypersensitivity reactions and acute anaphylaxis. Immunization of recently developed transgenic mice, whose endogenous μ heavy and κ light chain Ig genes are inactivated and which carry human Ig gene segments, with a digoxin-protein conjugate has enabled us to generate and isolate eight hybridoma cell lines secreting human sequence anti-digoxin mAbs. Six of the mAbs have been partially characterized and shown to have high specificity and low nanomolar affinities for digoxin. In addition, detailed competition binding studies performed with three of these mAbs have shown them to have distinct differences in their digoxin binding, and that all three structural moieties of the drug, the primary digitoxose sugar, steroid, and five-member unsaturated lactone ring, contribute to Ab recognition.

Pediatric spinal bone marrow: assessment of normal age-related changes in the MRI appearance

A retrospective study of 100 children (0-15 years) without known bone marrow abnormality, was performed to elucidate the spectrum of the MRI appearance of spinal bone marrow with age on T1-weighted images at 0.5 T. Fatty marrow distribution and vertebral signal intensity (SI) relative to disk SI were noted in each subject, and allowed the identification of distinctive patterns. The spinal marrow patterns and their relative frequency for different age groups were consistent with the known physiologic conversion from cellular to fatty marrow with age. Between the ages of 0 and 1 year, SI of corporeal ossification centers was similar or lower than SI of adjacent cartilage and disk in 87% of cases. Between the ages of 5 and 15 years, vertebral SI was higher than SI of adjacent disks in 90% of cases. A central or basivertebral zone of high SI consistent with focal fatty marrow was found in 16% and 31% of cases respectively. In conclusion, knowledge of these conversion patterns should serve as a practical aid in the interpretation of MRI examinations of the spine in children.

[Transesophageal echocardiography in the study of intracardiac thrombosis, tumors and vegetations]

Of 200 consecutive patients, studied with transesophageal echocardiography the findings were analyzed with respect to the presence of thrombi, tumors or vegetations. Thrombus formation was detected in 18 patients; their location and associated pathology are described. Tumors were present in 9 cases and in 10 patients endocarditis in native or prosthetic valves. The information obtained by transesophageal echocardiography was compared with transthoracic echocardiographic data. Transoesophageal echocardiography was demonstrated to be more sensitive, especially in the detection of intracavitary masses in the posterior structures of the heart.

[Muscular manifestations in periodic disease]

Between 1976 and 1983, the authors studied 50 new patients affected with periodic disease. 16 of them-mean age: 29-presented muscular manifestations. They may be grouped into two clinical aspects: muscular pain and contractures. The authors consider that these symptoms, first described in 1945, are an inherent part of the clinical picture of the disease. They discuss their relationship with periarteritis nodosa and remind the fact that their pathogenesis remains unknown.