A comparative study of biodegradability of a carcinogenic aromatic amine (4,4'-diaminodiphenylmethane) with OECD 301 test methods

4,4'-Diaminodiphenylmethane (MDA) is a widely used compound in industries. Studies on the biodegradability of MDA are necessary for environmental hazard identification and risk assessment. Previous studies have suggested that MDA was not readily biodegradable. In the present study, three batches of biodegradation tests (OECD 301A, B, D and F tests) were performed on MDA in June, August and December of 2012. MDA was found to be readily biodegradable and produced colored intermediates in the 301A, B and F test systems. MDA biodegradation measurements were consistent among the three batches of tests. Differences in the extent of biodegradation determined in different methods originated from different test conditions and assessment endpoints. The 301D test has stringent test conditions and is usually performed on chemicals that are toxic to microorganisms, so the test results obtained from 301D tests are less meaningful for evaluating the biodegradability of MDA. The low MDA biodegradation measurements in the 301B tests compared to the 301A and F tests were due to the assessment method, which did not account for MDA incorporation into biomass in its calculation of CO2 formation rate. The differences in the biodegradation rates, as measured by the different OECD 301 test systems, could also be related to the structure and properties of the chemical. For test substances that can be assessed by all OECD 301 test methods, the highest biodegradation values may be obtained from the 301A and F test methods. This study provides new information to assess the environmental fate in the risk assessment of MDA.

Uterine unification: indications and technique

Uterine unification procedures were performed on 17 patients with müllerian anomalies in an attempt to achieve reproductive capability. None of the 17 patients had any living children prior to undergoing these metroplasties. Fifteen patients had a septate uterine anomaly that necessitated use of the modified Jones procedure. The Strassmann procedure was performed in 2 patients, one with a bicornuate uterus and one with a didelphys uterus. After analyzing the follow-up data on 16 of these patients, 12 have conceived at least once (resulting in a total of 15 pregnancies), 3 of those who have not yet conceived have had unprotected intercourse for less than 10 months, and one is utilizing contraception electively. The use of the modified Jones procedure and the Strassman procedure in appropriate circumstances can maximize a patient's chances for fertility with minimal surgical risks.