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Biomedical subjects

E J Holmes

Publications and source records attributed to E J Holmes.

18 recordsLinked to original sources
PubMed1984

Stimulus equivalence after inferior temporal lesions in monkeys.

Monkeys with inferior temporal cortex lesions and unoperated monkeys were trained to discriminate pairs of objects and then tested for transfer after the original discriminanda were made larger or smaller, rotated, or presented as two-dimensional projections. The two groups of monkeys transferred equally well to the discriminanda altered in size or orientation, but only the unoperated animals transferred to the two-dimensional representation.

Animals↗
PubMed1984

Effects of inferior temporal lesions on discrimination of stimuli differing in orientation.

Monkeys with inferior temporal (IT) cortex lesions were compared with normal and operated control monkeys on a series of two-choice visual discrimination problems. In some problems, the discriminanda were different patterns or objects whereas, in other problems, the discriminanda were identical patterns or objects presented in different orientations. The animals with IT lesions were significantly impaired in learning to discriminate the different patterns and objects; however, they were not impaired in learning to discriminate stimuli which differed only in orientation by 60 degrees or more. These results help to specify further the role of the IT cortex in visual associative learning by demonstrating that there are some types of visual discriminations which are not sensitive to IT lesions.

Animals↗
PubMed1983

Ablations of the mammillary nuclei in monkeys: effects on postoperative memory.

A new procedure was developed for ablating the mammillary nuclei in nonhuman primates via direct visual exposure. Using this technique, monkeys receiving lesions of the mammillary nuclei were compared to control animals after surgery to assess the retention of preoperatively acquired visuospatial discriminations and subsequent postoperative ability to attain a demanding spatial memory task. Although the lesions proved to be accurate and complete, no changes in gross behavior or deficits in preoperatively acquired visual and spatial behaviors were noted. The monkeys with mammillary body lesions were, however, impaired in their ability to acquire postoperatively the demanding spatial memory task. These findings are consistent with previous investigations suggesting that the mammillary bodies are involved in the acquisition of spatial discriminations and skills.

Animals↗
PubMed1977

Crystalloids of prostatic carcinoma: relationship to Bence-Jones crystals.

Previously undemonstrated protein crystalloid structures were found to occur in the malignant acini of prostatic carcinomas in 23% of cases systematically reviewed. Histochemically and immunohistochemically, they appear closely related, if not identical, to Bence-Jones crystals. Thus, the prostatic carcinoma cell is the first neoplastic cell besides those of the lymphocytic-plasmacytic series shown to produce such crystalline structures. Like the proteolytic splitting of amyloid from Bence-Jones proteins, it is postulated that prostatic epithelium may enzymatically split corpora amylacea from a Bence-Jones-like protein which it synthesizes. It is further postulated that malignant prostatic cells may lack the necessary enzymatic machinery to accomplish this with resultant accumulation of crystalloids within their acini. Prostatic crystalloids were never found in benign glands with rare exceptions and then were limited to benign appearing glands adjacent to carcinoma. The presence of such crystalloids in microscopic sections of prostate may be of diagnostic aid in determining the presence of malignancy or of a premalignant state.

Amyloid↗
PubMed1976

Tumors of the pilosebaceous unit induced in the rat by the intravenous administration of 7,12-dimethylbenz(A)anthracene.

Six of 70 female Sprague-Dawley rats given a single intravenous injection of 7,12-dimethylbenz[a]anthracene (DMBA) developed 7 pilosebaceous tumors. Two of the tumors showed differentiation toward the upper portion of the pilosebaceous unit while 5 showed differentiation toward the lower portion. Each tumor was examined histochemically for the presence of inner root sheath keratin of the hair follicle using the carbamido diacetyl reaction for citrulline and for hair shaft keratin using boiling ninhydrin reagent. The 2 tumors of the upper portion of the pilosebaceous unit were sebaceous adenomas which were accompained by a keratinizing epithelim like that of the sebaceous gland duct and upper pilosebaceous canal. Histochemically, the keratin was not like that of hair shaft nor inner root sheath. The 5 tumors showing differentiation toward components of the lower pilosebaceous unit were trichoepitheliomas. They were composed of structures which, to varying degrees, recapitulated the organization of the normal hair follicle. Within these follicular structures, both inner root sheath and hair shaft type keratins were found. The occurrence of skin tumors after the intravenous administration of DMBA was unexpected since it is uncommon for skin tumors to be produced by the systematic administration of chemical carcinogens and they have never been described after the oral administration of DMBA. That the route of administration may influence tumor production with this carcinogen is suggested by the fact that the only other reported tumors, which were squamous carcinomas, also followed intravenous injection of DMBA.

9,10-Dimethyl-1,2-benzanthracene↗