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Biomedical subjects

J L Craft

Publications and source records attributed to J L Craft.

At least 37 records · Page 2Linked to original sources
PubMed1982

Induction of ocular neoplasms in Fischer rats by intraocular injection of nickel subsulfide.

Nickel subsulfide, alpha Ni3S2, was administered to albino Fischer rats by a single injection into the vitreous body of the right eye (0.5 mg alpha Ni3S2/rat, suspended in 20 microliter of NaCl vehicle). Control rats received a similar injection of the vehicle. Malignant tumors developed in the injected eyes of 14/15 alpha Ni3S2-treated rats by 8 months (vs. 0/11 controls, p less than 0.001). Five of the injected eyes of alpha Ni3S2-treated rats contained multiple tumors. The 21 eye tumors that were induced by alpha Ni3S2 included 11 melanomas, four retinoblastomas, three gliomas, and three unclassified malignant neoplasms. Three of the melanomas developed extraocular extensions; one of the melanomas metastasized to lungs and brain. Although the melanomas arose from amelanotic uveal melanocytes, melanosomes were observed in electron micrographs of the tumor cells. This study provides a new experimental model for chemical induction of ocular neoplasms. As a procedure to test the carcinogenicity of nickel compounds, intraocular injection has the advantages of short latency period, high tumor incidence, and ease of tumor detection.

Animals↗
PubMed1981

Effects of changing compatibility relationships on reaction time to the first stimulus in a double-stimulation task.

This study investigated the effects of manipulating the response requirement to the second stimulus (S2) on reaction time (RT) to the first stimulus (S1) in a double-stimulation choice RT task. Forty subjects responded to the 100 msec presentation of a left or right light by pressing the key on the same or opposite side as the light. Treatment conditions included a single-stimulation control (no S2 presented), and two double-stimulation conditions each requiring two responses (R1 and R2) in close succession, in one of these latter conditions, the rule governing R2 was the same as that governing R1 while, in the other, the rule governing R2 changed. Results showed the typical double-stimulation effect; i.e., increased latency of R1 when it was followed by S2 - R2. More importantly, R1 latency was increased further when the rules governing R1 and R2 were different. Results are discussed in terms of divided preparation capacity as well as other theories of the psychological refractory period.

Journal Article↗
PubMed1981

Feline uveal melanoma model induced with feline sarcoma virus.

This paper described the first animal model of a virally induced uveal melanoma. Tumors developed following the injection of an RNA tumor virus, i.e., Gardner strain feline sarcoma virus, into the anterior chamber of newborn kittens. Histologically, the tumors were found to be iris and ciliary body melanomas, many of which showed invasion. The histology and ultrastructure of those tumors are described.

Animals↗
PubMed1980

Retinal anomalies in trisomy 18.

The eyes of three patients with trisomy 18, the second most common human autosomal trisomy, were examined histopathologically. In the posterior retina transmission and scanning electron microscopic examinations reveal cytological details characteristic of immature neural retinas. We are able to confirm the report that the posterior retinal pigment epithelium in trisomy 18 has a paucity of mature melanosomes and, in fact, resembles human albino retinal pigment epithelium. The asociation of hypopigmentation and retinal immaturity suggests pigmentation plays a role in the control of the maturation of the neural retina.

Chromosomes, Human, 16-18↗
PubMed1979

Intraocular reticulum cell sarcoma: a case report and literature review.

A 66-year-old white woman with a confusing spectrum of central nervous system signs and symptoms had a diagnostic enucleation of her blind left eye showing retinal infiltration. Histopathologic examination showed reticulum cell sarcoma involving the retina. The patient died one month later and autopsy revealed diffuse central nervous system reticulum cell sarcoma along with right eye and systemic involvement. A review of the literature indicates intraocular reticulum cell sarcoma to be an apparently uncommon occurrence, although ocular examination may be frequently overlooked.

Aged↗
PubMed1979

Vascular basophilia in ocular and orbital tumors.

The occurrence of vascular basophilia in ocular tumors has been a selective histologic feature of retinoblastomas. We recently observed a metastatic oat-cell carcinoma to the choroid which also demonstrated such a vascular hematoxyphilia. Histologic review of a variety of ocular and orbital metastatic carcinomas failed to yield a similar basophilic pattern. Examination of 100 consecutive retinoblastomas for vascular basophilia revealed an incidence of 6.0%. Similar material was not seen in any of 125 melanomas, including 10 with areas of necrosis. Histochemical studies showed the basophilic material to be DNA, and electron microscopy revealed the nuclear debris of pyknotic tumor cells to be continuous with identical material surrounding the adjacent blood vessels. The pathogenesis of vascular deposition of DNA in these two ocular tumors remains unclear. This finding most likely represents a form of tumor activity requiring comparatively healthy blood vessels to adequately precipitate liberated nucleic acids being filtered from the necrotic and degenerating tumor tissue.

Basophils↗
PubMed1978

Human albinism. Light and electron microscopy study.

The eyes of a 13-year-old leukemic boy with the attributes of tyrosinase-negative oculocutaneous albinism were obtained for light and electron microscopic study. Repeated examinations had failed to reveal WBCs with giant oxidase-positive granules, and leukemic involvement of the fundus never occurred. Light microscopic examination of horizontal and vertical sections through the retina confirms earlier reports that the fovea is absent in albinos. The synaptic apparatus of the photoreceptor terminals appears abnormal. The rough endoplasmic reticulum of the retinal pigment epithelial cells is sparse though the presence of phagosomes suggests that phagocytic function is intact. Suggestions as to the importance that the morphological findings may have on albino visual function are made.

Acute Disease↗
PubMed1978

Human retinal dysplasia.

We studied the ultrastructure of the four types of dysplastic rosettes and compared them with retinoblastoma rosettes. Dysplastic rosettes have morphologic characteristics intermediate between the normal photoreceptor layer and retino-blastoma rosettes; Müller cells contribute to the formation of dysplastic but not neoplastic rosettes. Abnormality in the relationship between the retina and the retinal pigment epithelium is frequent in cases with spontaneously occurring retinal dsyplasia and is consistent with previous observations that the retinal pigment epithelium influences the development of retinal morphology and function. We believe the normal developmental sequence of cell death and disappearance of necrotic cells may have gone awry in retinal dysplasia.

Abnormalities, Multiple↗
PubMed1977

Ocular manifestations of focal dermal hypoplasia syndrome.

Although 40 percent of patients with the focal dermal hypoplasia syndrome have ocular abnormalities, to our knowledge, only one case of this condition has been previously described in the ophthalmic literature. Two additional cases are presented, and the systemic and ocular findings are reviewed.

Adolescent↗
PubMed1975

Light and electron microscopic study of dysplastic rosette-like structures occurring in the disorganized mature retina.

Histopathologic examination of six, adult human eyes revealed "rosette-like" structures in the retina which appear to have developed after maturation of the retina. These structures resemble dysplastic rosettes which are generally interpreted as a sign of maldevelopment of the retina (retinal dysplasia). The underlying lesions in the eyes of these patients were ocular ischemia, sickle-cell retinopathy, diabetic retinopathy, central retinal vein occlusion, and trauma. It is suggested that a distinction should be made between these degenerative-regressive changes and dysplastic rosettes which represent an abortive attempt of regeneration by germinal cells.

Adult↗
PubMed1975

Effects of stimulus-response correspondence and verbal expectancy on choice reaction time.

The effects of S-R correspondence, verbal prediction, and stimulus discriminability were examined in a discrete, two-choice reaction-time task. Correctness of prediction and S-R correspondence were significant main effects. In addition, responses were significantly faster for correct predictions on noncorresponding trials than for incorrect predictions on corresponding trials. This latter finding indicates that an expectancy mechanism can partially offset the negative effect of spatial S-R noncorrespondence on absolute magnitude of choice reaction time.

Adolescent↗