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Biomedical subjects

E Macher

Publications and source records attributed to E Macher.

At least 91 records · Page 5Linked to original sources
PubMed1976

Membrane associated antigens of human malignant melanoma. II. Leucocyte migration studies with formalin fixed human melanoma cells.

The leucocyte migration test from caillary tubes was examined for its usefulness as an assay for cell-mediated immunity in melanoma patients. Formalin fixed melanoma cells either obtained from established cell lines or freshly excised tumors were used as antigen source. From a group of 33 melanoma patients 14 reacted positively (42%) when fixed cultured cells were used, whereas, no positive reactions were found in a group of 14 control donors. However, a considerable proportion of patients with chronic inflammatory processes of the skin reacted positively (4/17 = 24%). A smaller proportion of positive reactions were found in melanoma patients when fixed melanoma cells from excised tumors were used (1/16 = 6%). The positive results in the group with chronic inflammatory processes may be explained as reactions against melanoma associated, but not melanoma-specific, antigens. Three possible reasons are discussed for the low frequency of positive reactions with cells from excised tumors: 1. the cells used in this study display only a few of the antigenic determinants typical for malignant melanoma, 2. antigen expression is quantitatively lower. 3. the surface antigens are covered by blocking factors.

Antigens, Neoplasm↗
PubMed1975

[Spontaneous regression and leukoderma in malignant melanoma].

In four patients with superficial spreading melanoma, partial spontaneous regression and/or leukodermas of different appearance occurred. In two patients leukoderma appeared within the central area of the primary tumor; one of whom developed, in addition, vitiligo elsewhere on the body. In a further case the melanoma exhibited a depigmented halo resembling Sutton's nevus. Presumably, these leukodermas represent an epiphenomenon of the specific immunological reaction between the host and the melanoma.

Adult↗
PubMed1975

Membrane associated antigens of human malignant melanoma. I. Internal labeling, detergent solubilization and characterization by homologous antisera and polyacrylamide gel electrophoresis.

Cultured melanoma cells were labeled with 3H-leucine over a period of 1-3 days. The labeled cells were mechanically disrupted and a preparation of "extranuclear membranes" was obtained by differential centrifugation. The membrane fragments were solubilized by the nonionic detergent NP-40 and the soluble material was double precipitated with antisera from melanoma patients and anti-human immunoglobulin sera. Because of the small quantitative differences of precipitated radiolabeled material between control and melanoma patients' sera, the precipitates were further analyzed on SDS-containing polyacrylamide gels. The labeled profiles of experimental and control gels now revealed clearcut differences usually seen in 2-3 characteristic peaks in the molecular weight range from 130,000-330,000.

Antigens, Neoplasm↗
PubMed1969

Studies on the sensitization of animals with simple chemical compounds. XII. The influence of excision of allergenic depots on onset of delayed hypersensitivity and tolerance.

In light of knowledge of the rate and route of dispersal of allergenic chemicals from ear sites (0.25 microg of picryl chloride, or 2:4 dinitrochlorobenzene in 0.25 microg and 5.0 microg amounts), dispersal was interrupted at selected times by ear excision. The animals exposed in this manner to different, tiny amounts of allergen were tested for development of contact type hypersensitivity. Both of these allergenic chemicals left the local ear site in about three phases of successively lengthening "half-lives." In the first phase, the escape rate was high. The principal pathway of escape was not via the lymphatics but via the blood vessels. Ear excisions made at 24 hr after injection of 0.25 microg of picryl chloride (PCl) or at 12 hr after injection of 5.0 microg of dinitrochlorobenzene (DNCB) essentially blocked onset of delayed type hypersensitivity, hence the first fraction to escape (80% of PCl, 98% of DNCB) was not used for sensitization. This large fraction serves rather to set up a state of specific tolerance, for these individuals showed extensive deficits in their ability to respond to a later sensitizing course. Also the ability to form hapten-specific antibody appeared nearly completely suppressed. Injections of allergen into the blood stream or directly in auricular nodes, in an amount approximating that which escaped early from the ear, also led to the same degrees of unresponsiveness-sometimes full, sometimes partial tolerance. The same types of specific tolerance were secured also by injecting subsensitizing doses into the ear, without excision, or into the flank and by contact tests applied to the flank. The allergen remaining in the ear after the early outflow, particularly between 12-24 hr and 3-4 days, appeared to constitute the sensitizing depot. The longer this depot was available to the animals the greater the immunological "information" for sensitization was picked up until the depot had served its full function around the 4th day. "Peripheral sensitization" was clearly demonstrable. The eventual degree of sensitivity attained by the animals was a resultant of two immunologic processes which occurred independently-tolerogenic effects of escaped chemical on the one hand and on the other the sensitizing effect of the local sensitizing depot of allergen bound in the ear tissue.

Allergens↗
PubMed1969

Studies on the sensitization of animals with simple chemical compounds. XI. The fate of labeled picryl chloride and dinitrochlorobenzene after sensitizing injections.

The fate of (14)C-labeled allergens injected intradermally into guinea pigs, namely picryl chloride (PCl*) and 2:4 dinitrochlorobenzene (DNCB*), was followed during the induction period of delayed hypersensitivity. Both chemicals were applied in a single injection into one ear in amounts that approached their minimal sensitizing doses (PCl, 0.25 microg; DNCB, 5.0 microg). Radioactivity in the various tissues was determined by liquid scintillation counting after combustion of tissues to CO(2) and H(2)O. The injected allergens seemed to leave the injection site in three phases. A large proportion of allergen escaped rapidly from the ear, about 50% within 3 hr in the case of PCl, within 15 min for DNCB, the difference probably reflecting their unequal reaction constants. Initially there was a "half-life" escape in 2.5 hr with injected dosage of 0.25 microg PCl and in 18 hr for 5.0 microg DNCB. This escape occurred via the regional veins and not via the lymphatics. Radioactive decomposition products of the allergens were already present in the urine within 3-4 hr. After 6-8 hr, the half-life time of escape lengthened to approximately 28 hr for both allergens used in their respective initial dosages, holding up to 2 days after which there occurred still further slowing; between 2 and 4 days the time was about 43 hr for PCl, much longer (72-88 hr?) for DNCB, apparently reflecting different physicochemical properties of this second fraction. Sensitization seemed to be connected with the portion that was present between 12 hr and 4 days of the induction period. It is not known how far the escape of radioactivity during this period may represent gradual hydrolysis of attached picryl and dinitrophenyl groupings, respectively, to form picric acid and dinitrophenol. Gradual accumulation of the second fraction in the regional lymph nodes could definitely be excluded. It was noted that no hypersensitivity arose and essentially no depot of radioactivity existed between 12 hr and 4 days when DNCB was injected in a dose of 0.25 microg, owing to its ready escape from the ear; but 20 times as much DNCB caused sensitization and provided about the same fixed depot as 0.25 microg of picryl chloride. After delayed hypersensitivity had been established, traces of radioactivity were still measurable at the site. This third fraction, probably representing a different coupling product, escaped at a very low rate and was traceable up through several weeks. No demonstrable radioactivity could be detected in thymus, spleen, and mesenteric nodes when examined at short intervals between (1/2) min and 17 days. In analogy with findings on transplantation "immunity" and with studies reported in the following paper, the induction of delayed hypersensitivity can be explained by encounters between lymphoid cells and the hapten complex which is found present in the local site for 4 days, in agreement with Medawar's concept of peripheral sensitization.

Allergens↗