Neuropathologic findings in short-term survivors of intraventricular hemorrhage.

Intraventricular hemorrhage (IVH) occurs in 31% to 43% of infants weighing less than 1500 g. Intraventricular hemorrhage is rarely an isolated lesion at autopsy. To document associated cerebral abnormality, 24 brains of infants with a diagnosis of IVH and who survived for at least one week were examined. The diagnosis was verified in 20 infants. Choroid plexus hemorrhage and brain calcification had been misdiagnosed as IVH in two infants and in two other infants, IVH was not evident at autopsy. Eleven infants (46%) had choroid plexus hemorrhage. Twenty-two infants (92%) had additional cerebral abnormalities: periventricular leukomalacia, brainstem necrosis, hydrocephalus, or cerebellar necrosis. This study demonstrates that IVH is rarely an isolated abnormality in the preterm infant brain. The associated brain lesions should be considered in attempts to prevent or treat IVH and their presence should be suspected during clinical assessment of survivors.

Applications of recombinant DNA to pathologic diagnosis.

Recombinant DNA techniques are contributing to the understanding of the pathogeneses of genetic, neoplastic, and viral diseases, and are used in the diagnosis of certain genetic and viral diseases. Such techniques will have wider application in the future and will play an increasing role in the clinical laboratory. The technology of this field rests upon the cleavage of DNA by certain enzymes, restriction endonucleases, and upon the ability to locate specific sequences of nucleotides in a cleaved DNA sample by using known fragments of DNA ("probes") labeled with radioisotopes or biotin. To produce useful probes, one "clones" multiple copies of the same DNA fragment in bacteria. The use of DNA probes in the clinical laboratory is valuable in antenatal diagnosis, genetic counseling, and post-natal diagnosis of genetic diseases, especially hematologic diseases and inborn errors of metabolism. DNA probes can also be used to detect viral genetic material in clinical specimens.