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Biomedical subjects

A Mayer

Publications and source records attributed to A Mayer.

At least 199 records · Page 11Linked to original sources
PubMed1981

Interaction of human carcinoma cells with an epithelial layer and the underlying basement membrane. A new model.

We have developed a new in-vitro model to study the interaction of malignant tumour cells with a normal epithelium and a subsequent invasion and penetration of the epithelium. The system involves the culture of human amnions obtained after caesarean section. The amnion with its intact basement membrane and the underlying collagenous stroma was cultured on an agar coated grid, tumour cells were added on top of the amnoin and co-cultured for up to 7 days. We report on human tumour cell lines, HeLa I also broke through the basement membrane and grew into the collagenous stroma. Normal cells were accepted by the amnoin and the amnoin epithelium grew over the fibroblasts. This system should provide a useful model to study the factors controlling tumour cell invasion, such as the role of proteolytic and collagenolytic enzymes, cell adhesion and locomotion.

Amnion↗
PubMed1981

[Radiotherapy problems by skin tumors in the facial folds].

The clinical observations of the higher incidence of recurrence after irradiation of skin cancer in the more furrowed and more articulated regions of the face are explained in part by physical-dosimetric measurements. We believe that the higher ratio of recurrences in these areas is attributable to several factors, such as the unfavorable patho-anatomical structure and the inherent difficulties in radiation therapy and to the inadequate determination of the tumor's depth extension.

Eyelid Neoplasms↗
PubMed1980

Simple and rapid separation of ortho- and paramyxovirus glycoproteins.

The hemagglutinin (HA) and neuraminidase (NA) of influenza viruses, as well as the fusion protein (F) and hemagglutinin-neuraminidase (HN) of paramyxoviruses, have been separated in native form using a two-step procedure. The glycoproteins are efficiently extracted from virions using the on-ionic detergent octyl-beta-D-glucoside and are then applied to a column of agarose beads coupled with tyrosine-sulfanilic acid. Pure HA and F are obtained in good yield in the flow-through from this column. NA and HN bind strongly and can be eluted, albeit somewhat contaminated with HA or F, by raising the pH of the column buffer. The separated non-denatured fractions can be used for structural, functional, and antigenic studies.

Chromatography, Affinity↗
PubMed1980

Maternally transmitted resistance to lymphoma development in mice of reciprocal crosses of the RF/J and AKR/J strains.

Females but not males of the low-lymphoma RF/J strain transmit a non-Mendelian factor which suppresses the development of lymphoma in F1 crosses with mice of the high-lymphoma AKR/J strain. Suppression of lymphoma was also evident in the first backcross generation to the parental AKR strain, but only when (RF female x AKR male)F1 mice had been the female parent. This "maternal resistance factor" was transmitted independently of the dominant, lymphoma-suppressing Fv-1n allele transmitted by both males and females of the RF strain, but the suppressive capacities of the two factors appeared to be additive. In this cross, F1 progeny of RF females also showed marked suppression of ecotropic murine leukemia virus expression by comparison with mice of the reciprocal F1 cross, but this suppression of virus expression was not detected in the lymphoma-suppressed AKR backcross population. The observation of lymphoma suppression in the absence of ectropic virus suppression in mice of the (RF X AKR)F1 female x AKR male backross generation indicates a qualitative or quantitative difference in the determination of these two effects.

Animals↗
PubMed1980

Genetically dominant resistance in mice to 3-methylcholanthrene-induced lymphoma.

Mice of the RF/J strain are highly susceptible to induction of thymic lymphoma by skin painting with 3-methylcholanthrene (MCA), whereas mice of the 129/J and I/LnJ strains are resistant. Resistance was the dominant trait in F1 mice of crosses of RF with each resistant strain. Analysis of the lymphoma incidence in MCA-painted backcross populations indicated segregation of a single dominant gene for resistance in both crosses. None of these strains show inducibility of the aryl hydrocarbon hydroxylase enzyme system, a phenotype attributed to the dominant Ahb gene which is also known to influence susceptibility to MCA-induced lymphoma. The occurrence of the disease in these backcrosses was independent of the hosts' phenotype at either the H-2 or Fv-1 locus, both of which have shown an influence on susceptibility to murine leukemia virus-associated lymphoma in other experimental systems.

Animals↗
PubMed1978

Fv-1 regulation of lymphoma development and of thymic ecotropic and xenotropic MuLV expression in mice of the AKR/J x RF/J cross.

The incidence of spontaneous thymic lymphoma has been studied in crosses between AKR/J and RF/J mice. AKR mice develop a high incidence of this disease. RF mice transmit a marked resistance to development of the disease to F1 hybrid mice of the AKR x RF cross. This resistance is associated with a reduction of endogenous ecotropic and xenotropic MuLV expression in the prelymphomatous thymus. The RF gene governing the coordinate suppression of these three phenotypes has been mapped to the Fv-1 locus. These results indicate that the particular Fv-1 allele of AKR mice provides a permissive genetic background for endogenous ecotropic and xenotropic MuLV expression and that these viral activities may be etiologically involved in the development of spontaneous thymic lymphoma in the mouse.

Aging↗
PubMed1977

Investigation of two deoxygenated haemoglobin-haptoglobin complexes by Mössbauer spectroscopy.

Haemoglobin Haptoglobin complexes formed when [Hp+]/[Hb]= 1/1 and [Hp]/[Hb] =2/1 were investigated by 57Fe Mössbauer spectroscopy. Both samples gave a spectrum consisting of a single quadrupole doublet. The temperature dependence of the quadrupole splitting was also identical for both samples. This proves that in both samples the nearest neighbour environment of the iron atom must be the same. A comparison with earlier investigations on myoglobin and haemoglobin indicates that the electronic structure of iron in the HbHp-complexes is similar to that in myoglobin.

Cold Temperature↗
PubMed1976

Patterns of invasive growth in vitro. Human decidua graviditatis confronted with established human cell lines and primary human explants.

Human decidua graviditatis was used as a receptor tissue to demonstrate invasive properties of human cells in vitro. In the confrontation between decidua and established cell lines of tumors and of normal origin as well as primary explanted cells, we noted differences in the cells' interactions with decidual tissue. The two original tumor cell lines, HeLa (carcinoma) and AFi (sarcoma), and a spontaneously transformed lymphoblastoid cell line showed aggressiveness, i.e., invasion, rapid proliferation, injury, and destruction of the decidual tissue. Strain HeLa S3 and two established cell lines, FL (amnion) and Girardi Heart, which are regarded as transformed cells because of their increased mitotic rate and polyploidy, exhibited various degrees of aggressiveness but did not invade. Freshly explanted fetal lung and endometrium caused no injury to the receptor tissue and were included in the decidual tissue.

Amnion↗