Matias Pardo

Ultrastructure of a fibroxanthosarcoma (malignant fibroxanthoma)

Primary and metastatic lesions from a fibroxanthosarcoma (FXS) originating in the neck of a 29‐year‐old Caucasian woman are reported. Light and electron microscopic observations are correlated to define the various types of cells constituting this neoplasm. Ultrastructural examination verified that several types of cells can act as facultative fibroblasts. Since a malignant potentiality cannot be predicted solely from the histopathology of fibroxanthomas, an attempt was made to categorize certain ultrastructural nuclear and cytoplasmic organelles associated with FXS cells. This was done in order to further define the malignant neoplastic cells of the FXS, so that distinguishing the malignant from benign forms of this neoplasm may become more feasible.

A cellular and malignant blue nevus: A light and electron microscopic study

A rare malignant blue nevus resected from the back of a 34‐year‐old Caucasian woman is reported. Histopathologic examination showed the presence of a CBN as well as MBN. The CBN elements of this lesion showed the characteristic prominent neural type fascicles intertwined with melanocytes. The deeper regions of this skin neoplasm showed considerable variation in histopathologic patterns. Metastascs to the axillary lymph nodes and multiple subdermal soft tissue sites, invasion of the underlying skeletal muscle, and several recurrences in the chest wall indicate that this neoplasm is malignant, though of a lower order than a malignant melanoma. The ultrastructural characteristics of neoplastic cells indicate that this neoplasm is of Schwann cell origin.

Immunohistochemical localization of a choriogonadotropin-like protein in bacteria isolated from cancer patients.

By the use of specific antibody to human chorionic gonadotropin (CG) as well as to its β‐subunit, and the application of the indirect fluorescein‐labeled and peroxidase‐labeled antibody techniques, we have demonstrated the presence of a membrane (wall)‐associated CG‐similar immunoreactive protein in 15 strains of bacteria isolated from tissues of patients bearing malignant neoplasms. These microorganisms were classified as S. epidermidis, (12), E. coli (2), and a single strain of P. maltophilia (ATCC 13637). The absence of the CG‐like antigen in other “cancer associated bacteria”, Streptococcus faecalis (ATCC 12818) and Pseudomonas aeruginosa (from patient with cancer of colon), demonstrated that not every “cancer associated bacteria” has the capability to synthesize the trophoblastic‐like protein. The negative results obtained with a number of “noncancer control” bacteria of known origin, obtained from ATCC and from clinical samples, strongly supported the idea that the existence of these CG‐like protein producing microorganisms is not a ubiquitous finding. The demonstration of a de novo bacterial biosynthesis of a protein having similar antigenic and biophysical properties to those of the human trophoblastic hormone, has great biological implications, especially if its biosynthesis is proven only in bacterial strains growing in the presence of cancer cells in which we have already demonstrated the presence of a similar antigen. The explanation of the phenomenon is unknown. Because of their origin, the potential of “genetic exchange” with subsequent expression of the mammalian gene by the bacterial cells becomes a possibility. It is also possible that the gene coding for the CG‐like protein is normally present but inactive or repressed in all bacteria.

Lysosomal Stability during Phagocytosis of Aspergillus flavus Spores by Alveolar Macrophages of Cortisone-Treated Mice

Control mice and those treated with cortisone were exposed to aerosols of viable spores of Aspergillus flavus. Fifteen to 20 minutes later, animals were killed, and alveolar macrophages were obtained by tracheobronchial lavage. Electron-microscopic examination of these cells revealed that, whereas the lysosomes of control macrophages showed extensive attraction and fusion with the phagocytic membranes surrounding spores, the lysosomes of macrophages from animals treated with cortisone revealed little, if any, interaction. This diminished lysosomal response in forming phagocytic vacuoles may be important in the subsequent development of hyphal bronchopneumonia which frequently, occurs in cortisonetreated mice exposed to spores of A. flavus.

Growth in vitro of Cells from Hyperplastic Nodules of Liver Induced by 2-Fluorenylacetamide or Aflatoxin B1

Cell suspensions obtained from hyperplastic nodules induced in rat liver by either of the two hepatic carcinogens, 2-fluorenylacetamide or aflatoxin B1, show growth when cultured in vitro. No growth of cells from liver adjacent to the hyperplastic nodules or from liver of control rats has been obtained so far under comparable conditions. Hepatocarcinoma cells induced by 2-fluorenylacetamide grow readily in vitro but behave differently. These findings suggest that some nonmalignant cells capable of growth in vitro arise during liver carcinogenesis prior to the appearance of unequivocal cancer. Cultures of such cells may offer new avenues for the study of liver carcinogenesis.

Immuno-Electron Microscopic Localization of a Choriogonadotropin-Like Antigen in Cancer-Associated Bacteria

The presence of choriogonadotropin-like material and its intimate association with the membranes of the wall of bacteria isolated from cancer patients, has been demonstrated by immuno-electron microscopy utilizing the indirect peroxidase-antiperoxidase-labeled antibody technique. The bacteria were an Escherichia coli strain isolated from a carcinoma of colon, and ATCC 25559 strain of Eubacterium lentum, an anaerobic microorganism originally isolated from a rectal tumor.

Pathogenesis of oncogenic simian adenoviruses: VI. An Ultrastructural Investigation of SV30 Replication☆☆☆

Abstract Newly synthesized infectious simian adenovirus 30 (SV30) was detected at 12–16 hours PI by titration of infectivity in two continuous kidney cell lines. These infectivity titers reached a maximum at 30 hours. Immunofluorescent observations correlated with the ultrastructural sequence of events. Intranuclear concentric membranes formed “tubes” which contained individual “coated” virus particles arranged in a linear order. Intranuclear rectilinear bars associated with “uncoated” nucleoids were also noted. In LLC-MK 2 and Vero cell cultures infected with SV30, increased numbers of intracytoplasmic annulate lamellae were apparent.

Pathogenesis of oncogenic simian adenoviruses: VIII. The histopathology and ultrastructure of simian adenovirus 7-induced intracranial neoplasms

Abstract A high incidence of intracranial (I.C.) neoplasms occurred following inoculation of simian adenovirus 7 (SA7) into newborn hamsters. The neoplasms appeared most often to originate from the choroid plexus; however, other I.C. sites were observed. Although several histopathological patterns of these neoplasms were noted, an undifferentiated type pattern usually predominated. Virus-like particles were noted by electron microscopy within in vivo and in vitro neoplastic cells. These particles were morphologically similar to those observed within neoplastic cells “superinfected” by SA7. Annulate lamellae were observed within in vivo and in vitro neoplastic cells.