Epoxy Resin Embedding in Contrast Radioautography of Bones and Teeth

Contrast, or low-resolution, radioautographs of teeth and large specimens of bone are made from plane, polished surfaces of such material embedded in plastic. The specimen is cut with a motor-driven circular saw, fixed, dehydrated, and defatted with anhydrous acetone and ether. It is then infiltrated with a mixture of epoxy resin and reactive hardener. The resin-infiltrated specimen is placed in an easily constructed mold of aluminum and Lucite. Polymerization is complete in 4-6 hr. The surface of the specimen is exposed by machining and/or abrading. The prepared surface is apposed to an X-ray type emulsion to produce a radioautograph. The resolution obtainable is estimated to be 100-200 β.     

The Metabolism of the Volatile Amines: IV. The Role of Drugs in the Pathogenesis of Hepatic Encephalopathy

The effects of certain drugs on metabolism of ammonia by the liver and kidneys in dogs were investigated by a technique in which both hepatic inflow and outflow bloods could be repeatedly sampled in unanesthetized healthy animals. Specific representatives of the classes of the drugs studied included thiopental (barbiturates), morphine (opiates and analgesics), promazine (tranquillizers), and chlorothiazide (oral diuretics).The three drugs commonly used as sedatives were all found to impair the ability of the liver to metabolize ammonia. The diuretic, by contrast, increased the amount of ammonia put into the systemic system by the kidneys. Ethanol appeared to have little or no direct effect on ammonia metabolism.The possibility exists that the occurrence of acute hepatic encephalopathy in patients with severe liver disease may be avoided in many cases if these drugs are administered with proper care. Results also indicated that current concepts of the pharmacological action of sedatives, opiates and tranquillizers may require revision.     

THE NON-ALLERGIC WHEEZE

Nearly every major disease of the lungs may be at one time associated with non-allergic wheezing and simulate asthma. The physiological production of wheezing is associated with air flowing through narrowed bronchi, and experimentally it can be induced when a high negative pressure is made in a tuberculous cavity. Wheezing is important as an early diagnostic symptom of polypoid bronchial tumors, both malignant and benign. By constantly keeping in mind the lesions which mechanically produce bronchial conditions which may cause non-allergic wheeze, appropriate diagnostic and therapeutic measures may be instituted early in the course of these diseases.