A neonatal complication of maternal leukaemia treated with 6-mercaptopurine

A High Throughput Approach to Reconstruct Partial-Body and Neutron Radiation Exposures on an Individual Basis

Biodosimetry-based individualized reconstruction of complex irradiation scenarios (partial-body shielding and/or neutron + photon mixtures) can improve treatment decisions after mass-casualty radiation-related incidents. We used a high-throughput micronucleus assay with automated scanning and imaging software on ex-vivo irradiated human lymphocytes to: a) reconstruct partial-body and/or neutron exposure, and b) estimate separately the photon and neutron doses in a mixed exposure. The mechanistic background is that, compared with total-body photon irradiations, neutrons produce more heavily-damaged lymphocytes with multiple micronuclei/binucleated cell, whereas partial-body exposures produce fewer such lymphocytes. To utilize these differences for biodosimetry, we developed metrics that describe micronuclei distributions in binucleated cells and serve as predictors in machine learning or parametric analyses of the following scenarios: (A) Homogeneous gamma-irradiation, mimicking total-body exposures, vs. mixtures of irradiated blood with unirradiated blood, mimicking partial-body exposures. (B) X rays vs. various neutron + photon mixtures. The results showed high accuracies of scenario and dose reconstructions. Specifically, receiver operating characteristic curve areas (AUC) for sample classification by exposure type reached 0.931 and 0.916 in scenarios A and B, respectively. R² for actual vs. reconstructed doses in these scenarios reached 0.87 and 0.77, respectively. These encouraging findings demonstrate a proof-of-principle for the proposed approach of high-throughput reconstruction of clinically-relevant complex radiation exposure scenarios.

Pregnancy outcome of women exposed to azathioprine during pregnancy

BACKGROUND

Azathioprine (AZP) interferes with nucleic acid synthesis and is teratogenic in animals. In view of the paucity of information on the use of AZP during pregnancy we investigated this subject in a prospective, controlled, multicenter study. Our objective was too determine whether exposure to AZP during pregnancy increases the risk for major malformations and to determine the effect on pregnancy outcome.

METHODS

Pregnant women on AZP who contacted one of seven teratogen information services were compared to a cohort of pregnant women who contacted two of the seven teratogen information services and took nonteratogenic treatments during their pregnancy.

RESULTS

Follow-up was completed on 189 women in the AZP group and compared to 230 women in the control group. The rate of major malformations did not differ between groups with six neonates in each; the AZP rate was 3.5% and the control group rate was 3.0% (p = .775; OR 1.17; CI: 0.37, 3.69). The mean birth weight and gestational age were lower in the AZP group (2,995 g vs. 3,252 g [p = .001, difference of mean: 257, 95% CI: 106.3, 408.1] and 37.8 weeks vs. 39.1 weeks [p = .001, difference of mean: 1.3, 95% CI: .5, 2.0], respectively). The AZP group had more cases of prematurity (21.4% vs. 5.2% [p < .001; OR 4.0; 95% CI: 2.0, 8.06]) and low birth weight (23% vs. 6.0% [p < .001; OR 3.81; 95% CI: 2.0, 7.2]).

CONCLUSIONS

These results suggest that AZP (50-100 mg/day) does not triple the rate of birth defects; however, it is associated with lower birth weight, gestational age, and prematurity. Larger studies are needed to confirm these observations.

Gross and cellular analysis of 6-mercaptopurine-induced cleft palate in hamster

The present study analyzes the morphological, histochemical, and ultrastructural aspects of the pathogenesis of 6-mercaptopurine (6MP)-induced cleft palate in hamster fetuses. Gross and light microscopic observations indicated that 6MP stunts the growth of vertical palatal shelves and thus induces cleft palate. Ultrastructural analysis showed that, in contrast to controls, 6MP-induced alterations were first seen in the mesenchymal cells 24 hr after drug administration. The initial alterations were characterized by swelling of the nuclear membrane. During the next 12 hr, lysosomes were seen first in the mesenchymal cells and then in the cells of the medial edge epithelium (MEE) of the developing palatal primordia. The appearance of lysosomes was temporally abnormal and was interpreted as a sublethal response to 6MP treatment. Subsequently, the nuclear alterations and the lysosomes diminished; and 48 hr after 6MP administration, they were absent from the palatal tissues. Ninety hours after 6MP administration, unlike the controls (in which the palatal shelves were already fused), changes were seen at the epithelial-mesenchymal interface in the developing cleft palatal shelves. These changes were characterized by breakdown of the basal lamina and epithelial-mesenchymal contacts. Eventually, at term, the MEE of the vertical shelf stratified. It was suggested that 6MP affected cytodifferentiation in the palatal tissues during the critical phase of early vertical shelf development and thereby induced cleft palate.

Third trimester chemotherapy and neonatal hematopoiesis

An 18-year-old woman with severe pancytopenia secondary to chemotherapy given in the third trimester of pregnancy and who delivered an infant with normal peripheral blood counts is reported. The literature is reviewed, and recommendations for the method of delivery in this setting are discussed.

Embryotoxic effects of doxorubicin and N-trifluoroacetyladriamycin-14-valerate (AD-32)

Anthracyclines are mutagenic, carcinogenic, and also cardiotoxic. Concern has been shown over the use of anthracycline anticancer drugs during pregnancy as these may be teratogenic to the human fetus. We have performed a series of experiments using the chick embryo to investigate and compare the toxic and teratogenic effects of doxorubicin (DX) and its new analog N-trifluoroacetyladriamycin-14-valerate (AD-32). DX and AD-32, dissolved in 1:1 emulphor/ethanol and diluted to 1:4 with water, were injected into the air sac of white leghorn chick eggs at dose levels of 1-20 micrograms (DX) and 5-100 micrograms (AD-32) per egg. Eggs received a single injection of the drugs on days 1 and 2 of incubation. Control eggs were injected with an equivalent volume of the drug vehicle (0.05 ml per egg). Both of the drugs caused embryonic death, stunted growth, and various gross morphological malformations. Surviving embryos were sacrificed when they reached 13 days of incubation. The LD50 values for days 1 and 2 were as follows: (DX, 2.5 micrograms/egg on day 1 and 0.9 microgram/egg on day 2; AD-32, 10.6 micrograms/egg on day 1 and 11.8 micrograms/egg on day 2). Stunting of growth, a common anomaly with both drugs, decreased sharply from day 1 to day 2. The studies demonstrate that both DX and AD-32 are toxic and teratogenic during the period of early organogenesis in the chick embryos. However, the toxic and teratogenic potentials of DX and AD-32 differ quantitatively. AD-32 is a more potent teratogen than DX when injected on day 1.

Acute leukemia in pregnancy: transient neonatal myelosuppression after combination chemotherapy in the mother

An 18-year-old primagravida received combination chemotherapy with vincristine, prednisone, L-asparaginase, cyclophosphamide, daunomycin, 6-mercaptopurine and central nervous system (CNS) prophylaxis with intrathecal methotrexate and whole-brain irradiation for acute lymphoblastic leukemia (ALL) beginning in the 12th week of pregnancy. Therapy resulted in sustained complete remission of the leukemia and delivery of a normally developed female infant whose immediate neonatal course was complicated by transient severe bone marrow hypoplasia. Our experience confirms the reports of others that intensive chemotherapy can be administered in the last two trimesters of pregnancy without serious teratogenic complications. However, we conclude that such therapy may cause significant myelosuppression in the newborn.