Subacute sclerosing panencephalitis: isolation of suppressed measles virus from lymph node biopsies.

Measles virus was isolated in mixed cultures of lymph node cells and HeLa cells. The agent was isolated by cocultivation from biopsy specimens of two of five patients with subacute sclerosing panencephalitis. The virus was identified by hemagglutination-inhibition, immunofluorescent, and neutralization tests. Biopsies from controls did not show evidence of measles virus.

The use of magnetic field effects on photosensitizer luminescence as a novel probe for optical monitoring of oxygen in photodynamic therapy.

The effect of a magnetic field on the steady-state and time-resolved optical emission of a custom fullerene-linked photosensitizer (PS) in liposome cell phantoms was studied at various oxygen concentrations (0.19-190 microM). Zeeman splitting of the triplet state and hyperfine coupling, which control intersystem crossing between singlet and triplet states, are altered in the presence of low magnetic fields (B < 320 mT), perturbing the luminescence intensity and lifetime as compared to the triplet state at B = 0. Measurements of the luminescence intensity and lifetime were performed using a time-domain apparatus integrated with a magnet. We propose that by probing magnet-affected optical emissions, one can monitor the state of oxygenation throughout the course of photodynamic therapy. Since the magnetic field effect (MFE) operates primarily by affecting the radical ion pairs related to type I photodynamic action, the enhancement or suppression of the MFE can be used as a measure of the dynamic equilibrium between the type I and II photodynamic pathways. The unique photo-initiated charge-transfer properties of the PS used in this study allow it to serve as both cytotoxic agent and oxygen probe that can provide in situ dosimetric information at close to real time.

Virus-like particles in geometric tubuloreticular structures.

Tubuloreticular structures of the geometric type were observed in dog osteosarcoma cells (D17a) before and after cocultivation with human placenta cells and before and after passage of the cocultivated cells through NIH nude mice. After passage through NIH nude mice, the reestablished cultures regularly produced conventional murine type-C particles and displayed budding virus-like particles (VLP) within the tubuloreticular structures. VLP, tentatively considered an aberrant form of type-C particles, were presumably of murine origin since they were not observed in the osteosarcoma cells before passage through NIH nude mice.

Mammary tumors, hepatocellular carcinomas, and pancreatic islet changes in C3H-Avy Mice.

Studies of tumor incidence and assorted lesions found in 187 C3H-Avy mice throughout their natural life-spans revealed the following: Hepatocellular carcinomas occurred in 54.3% of males, mammary carcinomas in 95% of females, pancreatic islet cell adenomas in 9.4% of males and in no females, and pancreatic islet cell hyperplasia in 41% of males and 23% of fefemales. Islet cell hyperplasia and adenomas appeared to consist predominantly of alpha and delta cells. Multiple tumors, or hyperplasia, or both, of a single site or of multiple sites occurred as frequently in males as they did in females--49.6% and 51.7% respectively. The most frequent neoplasms were hepatocellular carcinomas and islet cell tumors or hyperplasia in males (45.7%) and multiple mammary tumors in females (30%). Heretofore unreported tumors found in this strain of mouse were 12 islet cell adenomas, 2 spindle cell tumors of the meninges and olfactory lobes, a squamous cell carcinoma of the nasal turbinates, and a schwannoma of the spermatic cord.

Type-C RNA viruses of the NIH nude mouse.

Several types of tumors from various species were propagated in NIH athymic nude mice. Subsequently, cell lines were established from the tumors and examined for evidence of type-C virus activity. Hybrid mice (NIH Swiss and BALB/c) harbored murine type-C viruses of three categories: N-tropic, B-tropic and X-tropic.

Isolation and characterization of viruses from natural outbreaks of reticuloendotheliosis in turkeys.

We have described the in vitro isolation of type-C RNA viruses from two outbreaks of a fatal neoplastic disease in turkeys we diagnosed as reticuloendotheliosis. The virus had a density of 1.16 g/ml in sucrose gradients, had a DNA polymerase capable of using both endogenous and exogenous (synthetic) templates, and was infectious in vitro for turkey and chick cells. The culture-propagated virus was oncogenic for turkeys. The virus isolates were unrelated to avian leukosis virus and antigenically identical to reticuloendotheliosis virus (REV) strain T. Thus our studies suggested that REV is a causative agent of naturally occurring, fatal leukosis in turkeys.

Classification of mouse thymic virus as a herpesvirus.

Classical herpesvirus particles were observed by thin-section electron microscopy in thymus tissues from mice inoculated with mouse thymic virus. Intranuclear particles measured approximately 100 nm in diameter, and cytoplasmic and extracellular particles measured 135 nm in diameter. The morphology of mouse thymic virus particles together with its properties of heat and ether lability suggest that thymic virus should be classified as a member of the herpesvirus group.

Dual-spatial integration for longitudinal localization of inclusions in turbid media.

We introduce a technique called dual-spatial integration (DSI) that is used to isolate and enhance inclusions that differ only by their longitudinal placement within a scattering medium. DSI uses three different source-detector configurations to section a scattering medium into three longitudinal zones. This sectioning permits the extraction of structures close to surfaces and the enhancement of those structures located in the central part of the medium. Both the simulation and the experimental results indicate that DSI has potential interest for applications in biomedical imaging such as optical mammography.

Characterization of murine sarcoma virus transformation of guinea pig cells and activation of an RNA tumor-like virus from nonproducer guinea pig cells.

Guinea pig embryo (GEP) cells were transformed in vitro by the Kirsten strain of mouse sarcoma virus (Ki-MSV). The transformed cells were found to release infectious virus continuously and produced high titers of group-specific (gs) complement-fixing (CF) antigen characteristics of the murine sarcoma-leukemia virus complex. Foci of transformed cells were similar in appearance to those obtained with Ki-MSV in mouse and rat cells. The transformed cells produced RNA dependent DNA polymerase and type C virus particles with a density of approximately 1.15 g/ml in sucrose gradients by 3H-uridine labeling. The transformed cells produced tumors when transplanted into newborn guinea pigs. A number of focus-derived clonal lines from Ki-MSV transformed cells were isolated and characterized. All the focus-derived lines were found to be either producers or nonproducers (NP). The NP guinea pig cells produced neither infectious virus nor viral antigens of the murine sarcoma-leukemia virus complex although they were morphologically indistinguishable from virus-releasing MSV transformed GPE lines and produced tumors when transplanted into newborn guinea pigs. However, the sarcoma virus genome could be rescued in these NP cells by cocultivation with "helper" murine leukemia virus (MuLV) releasing GPE cells. Particles resembling guinea pig leukemia virus were activated from guinea pig NP cells or cultured normal guinea pig cells following chemical treatment. These particles were approximately 100 nm in the mature form and had a density of 1.16-1.17 g/ml. They contained RNA dependent DNA polymerase activity.

Fabrication and characterization of a solid polyurethane phantom for optical imaging through scattering media.

A phantom based on a polyurethane system that replicates the optical properties of tissue for use in near-infrared imaging is described. The absorption properties of tissue are simulated by a dye that absorbs in the near infrared, and the scattering properties are simulated by TiO2 particles. The scattering and absorption coefficients of the plastic were measured with a new technique based on time-resolved transmission through two slabs of materials that have different thicknesses. An image of a representative phantom was obtained from time-gated transmission.

Characterization of non-producer human cells induced by Kirsten sarcoma virus.

Non-producer (NP) human cells induced by the Kirsten sarcoma virus were characterized. These morphologically altered NP cells produced neither infectious virus nor complement-fixing antigens of the murine sarcoma-leukemia virus complex. The NP cells did not release RNA-dependent DNA polymerase and type-C virus particles with a density of approximately 1.15 g/ml in sucrose gradients by 3H-uridine labelling. The NP cells produced tumors when transplanted subcutaneously into athymic nude mice. The tumor cells re-established in culture resembled the orginal NP cells, were confirmed as human cells by karyological analysis and were also found to be "non-producer". The sarcoma virus genome in NP cells could be rescued not only by co-cultivation with "helper virus"-releasing cells but also by superinfection with helper type-C viruses. Murine (Rauscher, Ki-MuLV, AT-124 and two other xenotropic viruses), feline, RD-114 and Simian (woolly monkey and baboon) type-C viruses possessed the ability to rescue the sarcoma genome from NP cells but not AKR leukemia virus. In addition, the feline leukemia virus titer obtained by the rescuing technique in NP cells was the same as those obtained in feline embryo and NP cells by CF induction assay.

5-Bromo-2'-deoxyuridine potentiation of transformation of rat-embryo cells induced in vitro by 3-methylcholanthrene: induction of rat leukemia virus gs antigen in transformed cells.

Low-passage rat-embryo cells were not transformed by 3-methylcholanthrene or by 5-bromo-2' deoxyuridine. However, prior treatment with bromodeoxyuridine, followed by treatment with methylcholanthrene, resulted in cell transformation about three subpassages after removal of the carcinogen. RNA-directed DNA polymerase activity could not be detected in either normal or transformed cells. However, gs-1 antigen specific for rat C-type RNA virus was detected in cultures derived from bromodeoxyuridine-treated cells. No gs-1 antigen for the C-type RNA virus was detected in cultures that had not been treated with bromodeoxyuridine during the 25 subpassages of these experiments.High-passage rat-embryo cells, derived from a different cell pool, were transformed by either methylcholanthrene or dimethylbenzanthracene without prior infection with an exogenous virus, and without prior treatment with bromodeoxyuridine, gs-1 antigen for C-type RNA virus was also detected in 4 of 4 randomly selected transformed cell lines; the gs-1 antigen was not detected in any of 4 nontransformed control cultures. Considering these and previously published findings, we conclude that the lowpassage cells cannot be transformed by methylcholanthrene because of powerful cellular controls over the endogenous virus. Bromodeoxyuridine triggers some expressions of the endogenous virus; thus, the bromodeoxyuridine-treated cells are more susceptible to the transforming effects of methylcholanthrene. High-passage rat cells do not maintain perfect control over expression of their endogenous virus; the cell cultures are susceptible to the transforming effects of chemical carcinogens.