Infrared studies of the dynamic aspects of hydrogen-bonding in hydroxylated metabolites of 2,5,2',5'-tetrachlorobiphenyl

Infrared spectral studies indicate that the hydroxylated 2,5,2',5'-tetrachlorobiphenyls (TCBs) exist in a dynamic equilibrium of free, intramolecular, and intermolecular hydrogen-bonded forms. The relative abundances of the various species depend upon the polarity of the solvents as well as the physical state of the compound resulting from different configurations, i.e., the monohydroxylated 2,5,2',5'-TCBs exist as cis and trans rotational isomers of OH with respect to the chlorine atom in the ortho position, and 3,4-dihydro-3,4-dihydroxy-2,5,2',5'-TCB exists as 2 trans conformers with the OH groups either axial-axial or equatorial-equatorial with respect to the plane of the attached ring. In the solid state, the dimer or polymer is preferred with intermolecular hydrogen-bonding occurring between OH groups.

Total anomalous pulmonary venous connection to the left vertical vein. A plain-film sign useful in early diagnosis

Total anomalous pulmonary venous connection to the left vertical vein often may be recognized on the plain postero-anterior chest radiograph by the characteristic supracardiac shadow. This "snowman sign" is useful in older patients but rarely is apparent in infancy. In such young patients the authors have discovered a density anterior to the trachea on the lateral chest radiograph. This finding is present prior to the appearance of the snowman sign and should prove useful in the early diagnosis of this anomaly, facilitating prompt, appropriate treatment. Five representative cases are tabulated and developmental and clinical aspects are reviewed.

The significance of coronary calcification detected by fluoroscopy. A report of 360 patients

Cardiac fluoroscopy to detect coronary calcification was performed on 360 patients before undergoing coronary arteriography for proven or suspected coronary artery disease. Among the 154 patients in whom coronary calcification was identified, 97% had significant coronary disease angiographically (≧ 70% stenosis). In this group, the distribution of one, two, and three vessel coronary disease was 9%, 25%, and 66% respectively. The prevalence of coronary calcification increased with age and severity of coronary disease, but no difference in males versus females was demonstrable. The angiographic severity of coronary disease increased with multiple vessel calcification; three vessel disease occurred in 45%, 66%, and 82% of patients with one, two, and three vessel calcification, respectively. Patients with hyperlipidemia or hypertension had no significant difference in the prevalence of coronary calcification. Among the 267 patients with significant coronary lesions, 56% had calcification detected by fluoroscopy.

Five of the 93 patients with no significant coronary disease angiographically had coronary calcification fluoroscopically. Four of the five had a prior history of myocardial infarction, and two showed asynergy on left ventriculography.

This study demonstrates that cardiac fluoroscopy is a valuable procedure for detecting significant coronary artery disease since this highly specific test is easily performed, inexpensive, noninvasive, and widely applicable for screening large patient populations.

Metabolism of DDT and Some Other Chlorinated Organic Compounds by Aerobacter aerogenes

The micro-organism, Aerobacter aerogenes, reductively dechlorinates o,p'-DDT to o,p'-DDD. The yield is constant for a constant 24-hour incubation period. This metabolic pathway appears to be rather specific for the DDT's, since Perthane is not produced from l,l,l-trichloro-2,2-bis(pethylphenyl) ethane even after long incubation with A. aerogenes. In general, incubation of methoxychlor with the bacterium results in loss of the pesticide: its olefin and the reductively dechlorinated pesticide [ (l,l-dichloro-2,2-bis (p-methoxyphenyl) ethane] are sometimes produced but only after long term incubation. A. aerogenes does not effect the conversion of aldrin to dieldrin.