Henry Pinkerton

Heterotransplantation of human glioblastoma multiforme and meningioma to nude mice.

Summary A human glioblastoma multi-forme (Br7) and a meningioma have been successfully xenografted sc in nude mice. Both were successfully passed to a second generation. Complete retention of the unique histologic features was noted in each tumor xenograft. Actively growing cultures from the glioblastoma xenograft have been established; they are composed of the cell types characteristic of glioblastoma. Immature and mature C-type particles, presumably representing a xenotropic mouse virus, are present in both grafts. The growth of these two tumors in nude mice may provide a useful model for etiologic, immunologic, and chemotherapeutic studies. An attempt to produce glioblastoma in nude mice by the injection of cells cultured from human glioblastoma T98 was unsuccessful.

Recovery of Virus Morphologically Identical with Psittacosis from Thiamin-Deficient Pigeons.

Summary and Conclusions A virus closely related to, if not identical with that of psittacosis was isolated from about 5% of 400 pigeons on a thiamin-deficient diet. The observations made suggest: 1. That pigeons should be added to the list of birds naturally infected with psittacosis virus and therefore of possible importance in the epidemiology of the disease, and 2. That thiamin deficiency may be capable of changing a latent infection with psittacosis virus into an active stage, with consequent danger of spread to other birds and to man. Acknowledgment should be made of the assistance of Dr. T. M. Rivers who kindly examined our sections and stated that the intra-cellular bodies seemed identical with those of psittacosis.

Inhibition of Growth of Typhus Rickettsiae in the Yolk Sac by Penicillin.

Conclusion Penicillin, injected in 3 doses at intervals of 48 hours, exerted a striking inhibitory action on the multiplication of murine typhus rickettsiæ in the yolk sac of the fertile hens egg.

The pathogenesis and pathology of virus infections.

The objectives of this paper are to discuss briefly the pathogenesis of viral lesions, with particular reference to neoplasia, and to describe the cellular alterations associated with the activity of a few selected viruses. Emphasis will be placed on cytological lesions rather than on inflammatory reactions, since the former are specifically related to the intracellular growth of virus particles, while the latter are secondary and non-specific in nature. Viruses, like bacteria, protozoa and fungi, cause lesions which range from suppurative or necrotizing lesions to granulomatous or proliferative ones, depending largely on the severity of cellular injury. Neoplasia may be considered as an extreme example of the proliferative type of reaction. Other than intact tumor cells, the only transmissible agents which are known to cause neoplasia are certain filterable agents, generally accepted as viruses, which induce tumors in lower animals and plants. Although some viruses form toxins, many viruses damage cells in a more intimate way. Nucleoprotein synthesis is diverted from its normal intracellular pathways to the formation of virus particles, and viruses compete with normal cytological components for metabolites of many types, some of which are probably intermediary in nature. Biochemical lesions of varied and subtle types are thus produced. The study of these biochemical lesions is in its infancy but the electron microscope and modern biochemical and histochemical methods promise rapid developments in this field. The available evidence suggests that virus particles of some types do not reproduce by division, but rather by acting as models or “seed crystals” for the synthesis of new particles of an identical or similar nature. Sudden mutations occur in viruses, and there is evidence that virus particles from one species of animal, on entering cells of a different species, may change their nature somewhat because the available building blocks differ slightly from those present in the original host. Malignant cells contain abnormal self-duplicating constituents of some type which are responsible for their continuous aggressive behavior. To deny this basic assumption is to discard what we have learned about cellular physiology. Cells do not live, reproduce, and behave in characteristic manner as individual units, but rather by virtue of genes, plasmagenes, mitochondria, enzymes, and other organoid structural components which they contain. With the exception of the evocators, or “organizers,” many of which appear to be sterols, these life-giving intracellular structures are composed largely of nucleoproteins. They are all self-duplicating, somewhat virus-like, and live in complex symbiotic equilibrium with each other and with the cells in which they reside. In a very few instances, the self-duplicating intracellular components responsible for neoplasia are filterable, transmissible, and decidedly virus-

Studies on virus induction by 5-bromodeoxyuridine in nonproducer murine sarcoma virus-transformed 3T3 cells

Abstract Treatment with 5-bromodeoxyuridine (BrdU) of nonproducer BALB 3T3 cells (KA31 cells) transformed by the Kirsten strain of murine sarcoma virus (Ki-MSV) induced the synthesis of DNA polymerase-containing particles which band in sucrose gradients at a density of 1.16 and utilize poly(I) (dC) 12–18 , a template-primer specific for RNA-directed DNA polymerase. In order to establish optimal conditions for virus induction, the induction process was studied by analysis of the culture fluid for polymerase activity and the induced cells for viral proteins by immunofluorescence and virus particles by electron microscopy. By varying the concentration and time of exposure to BrdU, it was found that the maximal level of polymerase activity was induced when cells were treated with 20 μg of BrdU for a 24-hr period, 24 hr after seeding. Under these conditions about 15% of the cells were induced to synthesize viral antigens detected with anti-Moloney MSV rat serum. The level of polymerase activity in the culture fluid and viral antigen in the cells became maximal at 3 days after BrdU treatment and decreased rapidly. Electron microscopy showed a large increase in the proportion of cells containing incomplete virus particles and in the number of particles per cell at 2 and 3 days after BrdU treatment. At 3 days after treatment, 82% of the cells contained incomplete virus particles within dilated vesicles of the endoplasmic reticulum as compared to 18% for untreated cultures. A high level of virus production could be maintained for at least 15 days by continuous maintenance of cells on 4 μg/ml of BrdU. It is not clear whether the mechanism involves continuous reinduction of virus or overcoming the normal inhibition of virus multiplication in these cells. Under these conditions, BrdU reversed the rounded, transformed appearance of KA31 cells to a flat fibroblastic morphology.

Effect of rifamycin and tilorone derivatives on friend virus leukemia in mice.

Summary Several derivatives of rifamycin, and analogs of the tilorone-fluoranthene group were tested for inhibition of splenic enlargement in Friend virus leukemia. At least three members of the rifamycin group caused significant inhibition (31-49%) as did at least three membes of the tilorone group (32-48%). These six compounds are among those found by others (6, 7) to be most inhibitory in vitro to the RNA-directed DNA polymerase of oncornaviruses. However our studies do not furnish direct evidence for or against a role of inhibition of the viral enzyme in the suppression of splenomegaly. None of the agents was as effective as methotrexate, which caused 90-92% inhibition. The activity of five of the agents was reduced, rather than enhanced by the injection of adjuvants (M. butyricum and pertussis vaccine). Three of the agents had a subtractive, rather than an additive effect on the inhibition caused by methotrexate alone.

Human breast carcinoma: Heterotransplantation to newborn rats

Cultured cells from a human breast carcinoma (HBC) were injected subcutaneously in newborn cortisone-treated Sprague-Dawley rats (CNBR). Tumors of predominantly epithelial nature appeared in all within 30 days, and wipespread metastases occured often. Cells cultured from these tumors rapidly produced similar tumors in CNBR. Rat-to-rat passage by implanting fragments of tumor tissue was 100% successful in CNBR. The in vivo model described is simple and inexpensive.

Chemotherapeutic Effectiveness of Alloxan in Murine Bartonellosis.

Conclusions Alloxan in relatively low and presumably nondiabetogenic dosages was found to be effective in preventing the development of murine bartonellosis, which invariably follows splenectomy in untreated carrier rats. The activity of this agent probably depends on its reaction with SH groups.

Chemoprophylactic effectiveness of aureomycin and terramycin in murine bartonellosis.

Conclusions Both aureomycin and terramycin, started 48 to 72 hours before the expected onset of illness and continued for 9 days were found to be effective in preventing murine bartonellosis. Rats treated with these compounds developed no evidence of illness while the morbidity in the control groups was 100%, and the mortality 50 to 100%. A few bartonellae appeared in the blood of some of the treated rats, but anemia and hemoglobinuria were prevented. The chemoprophylactic effectiveness of these 2 compounds in murine bartonellosis is in contrast to negative results obtained with a wide variety of other antibiotics.

Characteristics of a Plaque Method for the Murine Salivary Gland Virus.

Summary Using a double agar overlay, MSGV produced discrete spherical plaques in mouse embryonic fibroblasts, but not in chick embryo, HeLa or L cells. Plaques appeared about 36 hours after seeding as single large rounded inclusion-laden cells, surrounded by wide clear zones. Centrifugal expansion by progressive involvement of adjacent cells resulted in plaque diameters of 0.2 to 0.8 mm by the 6th day. Fluid medium from infected bottle cultures commonly contained 1 × 107 PFU/ml. A linear relationship was found between plaque counts and virus dilution. The virus was markedly stable when stored for 5 hours in PBS with 2% calf serum, but rapid loss of titer occurred if serum was omitted. Virus titer and CPE production in vitro were not significantly altered during 120 passages, but pathogenicity for mice was lost after about 36 passages.