Biomedical subjects

C M Leonard

Publications and source records attributed to C M Leonard.

At least 73 records · Page 4Linked to original sources

PubMed1977

Cell-mediated immune responses of breast cancer patients to autologous tumor-associated antigens.

Lymphocyte proliferation assays with autologous tumor material in mixed leukocyte-tumor interactions (MLTI) were employed to monitor tumor-associated cell-mediated immune responses of peripheral blood lymphocytes from patients with carcinoma of the breast. In addition, leukocyte migration inhibition (LMI) assays were employed to compare reactivity to autologous breast-tumor extracts versus allogeneic breast-tumor extracts. Positive lymphoproliferative responses to tumor-associated antigens (TAA) were observed in the MLTI assay with the use of either intact autologous tumor cells or crude extracts (in mug and ng quantities) in 12 of 34 (35%) breast cancer patients studied. Positive reactivity to tumor, but not to normal tissue of reactive patients, was observed in repeated assays. Finally, patients demonstrating positive MLTI responses to autologous tumor extracts likewise responded in LMI assays to these same autologus extracts as well as to allogeneic breast-tumor extracts, but not to non-breast-tumor extracts. Thus breast tumors appeared to possess common TAA among both male and female patients.

Antigens, Neoplasm↗

PubMed1976

Central control of song in the canary, Serinus canarius.

We have traced central nervous pathways controlling bird song in the canary using a combination of behavioral and anatomical techniques. Unilateral electrolytic brain lesions were made in adult male canaries whose song had been previously recorded and analysed on a sound spectrograph. After several days of postoperative recording, the birds were sacrificed and their brains processed histologically for degeneration staining with the Fink-Heimer technique. Although large lesions in the neostriatum and rostral hyperstriatum had no effect on song, severe song deficits followed damage to a discrete large-celled area in the caudal hyperstriatum ventrale (HVc). Degenerating fibers were traced from this region to two other discrete nuclei in the forebrain: one in the parolfactory lobe (area X, a teardrop-shaped small-celled nucleus); and a round large-celled nucleus in the archistriatum (RA). Unilateral lesion of X had no effect on song; lesions of RA, however, caused severe song deficits. Degenerating fibers from RA joined the occipitomesencephalic tract and had widespread ipsilateral projections to the thalamus, nucleus intercollicularis of the midbrain, reticular formation, and medulla. It is of particular interest that direct connections were found onto the cells of the motor nucleus innervating the syrinx, the organ of song production. Unilateral lesions of n. intercollicularis (previously implicated in the control of vocal behavior) had little effect on song. One bilateral lesion of HVc resulted in permanent (9 months) and complete elimination of the audible components of song, although the bird assumed the posture and movements typical of song. Preliminary data suggest that lesions of the left hemisphere result in greater deficits than lesions of the right one. This finding is consistent with earlier reports that the left syrinx controls the majority of song components. Results reported here suggest a localization of vocal control in the canary brain with an overlying left hemispheric dominance.

Animals↗

PubMed1975

Developmental changes in olfactory bulb projections revealed by degeneration argyrophilia.

The maturation of the main and accessory olfactory bulb projections to the ventral forebrain of the golden hamster has been traced by using the Fink-Heimer silver technique to stain degenerating axons and terminal arborizations after bulbectomy at different ages between birth and 33 days. In the youngest pups, long-lasting degeneration argyrophilia (LLDA) is found in two regions of prepiriform cortex: at the level of the rostral tubercle and rostral amygdala. By five days of age the caudal region exhibiting a long-lasting degeneration reaction extends from the middle of the olfactory tubercle to the middle of the amygdala. The olfactory tubercle, medial and cortical amygdala and entorhinal cortex subsequently develop substantial LLDA at ages varying between 9 and 13 days. In a previous study (Leonard, '74b) the onset of LLDA in optic tract terminals in the superior colliculus was found to coincide with the age of eye opening and the onset of a stage of rapid snyapse formation. Since different olfactory responses appear at different times during the golden hamster pup's first two weeks of postnatal life, it seems possible that the onset of LLDA in different regions of the olfactory projection at different ages may be related to the onset of different specific olfactory functions.

Amygdala↗

PubMed1975

Lymphocyte blastogenesis induced by potassium chloride extracts of allogeneic breast carcinoma and lymphoid cells.

Lymphocytes from cancer patients and normal individuals demonstrated blastogenesis with allogeneic potassium chloride (3 M KCl) extracts of breast carcinoma cells. Normal individuals reacted with a greater frequency and stronger blastogenic responses to tumor extracts than did breast carcinoma patients; allogeneic extracts may have elicited recognition of normal alloantigens rather than tumor-associated antigens. Normal individuals also responded to 3 M KCl extracts of allogeneic pooled normal leukocytes, normal breast tissue, and other cancers, but did not react to extracts of autologous leukocytes.

Antibody Specificity↗

PubMed1975

Functional activities of rosette separated human peripheral blood leukocytes.

Subpopulations of human peripheral blood leukocytes were isolated by rosette formation and tested for functional activity. E -rosette-forming cells (E-RFC) and EAC-RFC were separated from non-resetting cells by sedimentation on Ficoll-Hypaque gradients. The efficiency of the method and the purity of the resulting subpopulations were high. E-RFC responded to PHA Con A, allogeneic leukocytes, and PPD, with higher levels of proliferative reactivity than the unseparated lymphocytes while E-RFC depleted, EAC-RFC, and null cells showed only low levels of reactivity. Reactivity to PWM and tetanus toxoid was also restricted to the E-RFC subpopulation, but was lower than that of unseparated cells. A staphylococcal antigen preparation triggered lymphoproliferative reactivity in the E-RFC, E-RFC depleted, EAC-RFC, and the null cell subpopulations. 51Cr release lymphocyte cytotoxicity against a human lymphoblast target cell line was found in the E-RFC and null cell fractions but was not observed with the EAC-RFC subpopulation.

Cell Separation↗

PubMed1974