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Biomedical subjects

E B Howard

Publications and source records attributed to E B Howard.

At least 55 records · Page 3Linked to original sources
PubMed1978

Steroid hormone receptor characterization of several histologic variants of a rat prostatic adenocarcinoma.

Several histologic variants of the transplantable R-3327 prostatic adenocarcinoma carried in male Copenhagen rats have been characterized and the histologic types have been correlated with steroid hormone receptor content. One type is clearly an adenocarcinoma; this tumor is hormonally responsive and contains substantial amounts of both androgen and estrogen receptors. In contrast, another histologic type, a fibrosarcoma, is hormonally nonresponsive and does not contain either receptor. A third histologic variant is classified as a carcinosarcoma and contains histological elements of both adenocarcinoma and fibrosarcoma and is also hormonally responsive. This tumor contains lower receptor levels than the adenocarcinomas but more than the fibrosarcomas. The androgen receptor appears to be identical in the different histologic forms of the tumor: the sedimentation coefficient is 7.8S and the dissociatiln constant for methyltrienolone is 4 x 10(-9) M. Similarly, the estrogen receptor from the different histologic forms of the tumor has a sedimentation coefficient of 8.3S and the dissociation constant for estradiol is 7 x 10(-10) M. These findings clearly distinguish the cytosol binding macromolecules from plasma binding proteins, and classify them as steroid hormone receptors. Further, rat serum was devoid of androgen and estrogen binding in the 8S region. Normal prostate tissue from Copenhagen rats contained low levels of an androgen receptor, but no estrogen receptor. It is possible that during growth and/or passage of the R-3327 tumor, the hormonally responsive adenocarcinoma cells do not survive and there is a gradual emergence of the nonresponsive fibrosarcoma. If, as we suspect, the receptors are found in the epithelial cells and not the stromal cells, there clearly should be considerable variation of receptor content in the different intermediary histologic forms of the tumor.

Adenocarcinoma↗
PubMed1976

Pulmonary tuberculosis in a sulfur-crested cockatoo.

An adult, female sulfur-crested cockatoo (Kakatoe sp) was examined because of dyspnea associated with hemoptysis. On radiographic examination there was a large cystic pulmonary mass that, on aspiration, was found to contain thick sanguineous fluid. Ziehl-Neelsen staining of aspirate smears revealed numerous acid-fast organisms. Gross necropsy and microscopic findings suggested a diagnosis of tuberculosis, with primary focus of infection in the pulmonary tissues. Bacteriologic isolation and typing confirmed a diagnosis of tuberculosis and established Mycobacterium avium as the etiologic agent.

Animals↗
PubMed1970

Strontium-90: effects of chronic ingestion on farrowing performance of miniature swine.

In experiments involving the ingestion of strontium-90 by nearly 800 female miniature swine and extending over three generations, no significant differences in litter size, percentage of stillborn, or birth weight were observed between controls and animals ingesting up to 625 microcuries of strontium-90 per day. At 625 microcuries per day, these animals were ingesting more than a million times the peak value of strontium-90 ever reported in the American diet. Animals on 3100 microcuries per day did not survive the gestation period. From these studies, it is evident that feeding levels of strontium-90 high enough to affect fetal or neonatal mortality in this species will not permit maternal survival long enough for the bearing of young.

Animals↗