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Biomedical subjects

R I Carp

Publications and source records attributed to R I Carp.

At least 127 records · Page 7Linked to original sources
PubMed1975

Multiple sclerosis-induced reduction in the yield of a mouse cell line.

Cultures of a mouse cell line (PAM) were treated with 71 multiple sclerosis (MS) and 45 non-MS samples. Of the cultures treated with MS material, 80 percent (58) showed a reduction in cell yield (compared to untreated controls) of at least 20 percent by the third passage after inoculation. The MS samples were from 40 MS cases, and a total of 36 cases yielded at least one positive sample. The agent responsible for the decrease was not limited to nervous tissue, but was also found in serum, cerebrospinal fluid, spleen, kidney, and lymph node of MS patients. Positive samples were present at every stage of the disease. None of the non-MS samples yielded cell counts significantly different from untreated controls. The non-MS category included 12 samples from healthy individuals, 13 assorted non-central nervous system disease samples, and the following central nervous system disease samples: six subacute sclerosing panencephalitis, three Huntington's chorea, two Parkinsonism, six amyotrophic lateral sclerosis, one stroke, one encephalopathy, and one epilepsy. Brain homogenates from mice inoculated with MS tissues elicited the decrease, whereas brain homogenates from mice inoculated with non-MS samples did not.

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PubMed1975

Comparative characteristics of three cytomegaloviruses from rodents.

One cytomegalovirus isolate from the vole (Microtus arvalis) and 2 cutomegalovirus strains from mice (Apodemus sylvatious and Mus musculus) were compared. The rates of inactivation of these 3 viruses were virtually identical after each of 3 treatments: Repeated cycles of freezing and thawing, ultrasonic vibration, and exposure to trypsin and chymotrypsin. The replication of the 3 viruses was similar in each of 3 types of mouse embryo fibroblast cells tested. A number of other characteristics of the vole isolate were the same as those of the mouse strains, including buoyant density (1.20 g/cu cm), enhanced plaquing efficiency in diethylaminoethyl-dextran, and induction of an abortive replication cycle in human cells. The 3 viruses were indistinguishable with regard to their antigenic characteristics, and electron microscopic examination revealed that the nucleocapsids and enveloped virions of the 3 viruses were indistinguishable.

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PubMed1974

Reduced cell yields of mouse cell line cultures after exposure to homogenates of multiple sclerosis tissues.

The total cell yields in cultures of a mouse cell line termed "PAM" were reduced markedly after exposure to multiple sclerosis (MS) homogenates. The reductions were noted as early as the second subcultivation. The effect was produced by eight of eight MS brain homogenates and three of three MS spleen homogenates; the samples were from 10 MS cases. The reduction in total cell yields (compared to medium-treated cultures) was not observed after exposure to homogenates, six brain and two spleen, from eight non-MS cases. The effect was produced by the 50-nm filtrate of a pool of MS brain homogenates. Five of the MS-inoculated cultures were maintained for 18 subcultivations, and the reduction in total cell yields persisted throughout the series. The capacity to induce the reduction in cell yields was present in cell-free lysates from five of five MS cultures at passage 18, as was the capacity to cause a decrease in the polymorphonuclear neutrophils in the peripheral blood of mice. Calculation of the dilution effect (at least 10(18)-fold) that had occurred by the end of the passage series proved that the factor(s) causing the cell change in culture and the polymorphonuclear neutrophil change in mice had replicated in PAM cells.

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PubMed1973

Influence of complement on the neutralization of murine cytomegalovirus by rabbit antibody.

Antiserum against murine cytomegalovirus produced in the rabbit contained complement (C')-requiring neutralizing (CRN) antibody. The proportion of CRN was extremely high (up to 98%) during the early portion of an immunization procedure, whereas the antisera produced late had a much lower proportion that required C'. The antiserum produced was specific for MCMV with or without C'.

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PubMed1972

Decreased percentage of polymorphonuclear neutrophils in mouse peripheral blood after inoculation with material from multiple sclerosis patients.

Mice inoculated with brain homogenates from multiple sclerosis (MS) cases showed marked changes in their leukocyte differential counts, with a decrease in per cent polymorphonuclear neutrophils (PMN) and an increase in the per cent lymphocytes. These changes were based upon an absolute decrease in the number of circulating PMN. The decrease in PMN percentages was apparent at 16 hr after infection and persisted for at least 11 months. The factor responsible for the decrease in PMN was (a) recoverable from 12 hr to 8(1/2) months after inoculation, (b) present in human brain homogenate at a concentration of 3 x 10(12), and (c) between 25 and 50 nm in diameter. Inoculation of 100 units of factor into mice and subsequent titration showed that the factor had undergone a net increase in the mouse of at least 10(9)-fold. The factor causing the PMN decrease was found in all MS material thus far tested: three brains, one spleen, three sera, and two cerebrospinal fluid (CSF) from nine cases of MS. The factor was not found in normal human material that included two brains, one spleen, two sera, and two CSF.

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PubMed1972

Scrapie-induced changes in the percentage of polymorphonuclear neutrophils in mouse peripheral blood.

A decrease in the percentage of polymorphonuclear neutrophils (PMN) in the peripheral blood of mice appeared 3 days after intracerebral (IC) inoculation with scrapie mouse brain homogenate. Mice inoculated IC with normal mouse brain had PMN percentages similar to those found for uninoculated mice. This difference between normal and scrapie-inoculated mice continued throughout the preclinical phase of the disease. In the clinical phase of the disease, the percentage of PMN was either higher or lower than that found in normals. The factor causing the decrease in PMN percentages was found in the filtrates from 220-, 100-, and 50-nm filters, but not in the filtrates from a 25-nm filter. Sodium periodate treatment of the scrapie brain samples eliminated their ability to cause the decrease in PMN percentages, whereas sodium iodate had no effect. In addition to two genetically different scrapie mouse brain isolates, homogenates of mouse spleen, sheep brain, and sheep spleen from scrapie-affected animals caused a decrease in percent PMN, whereas the corresponding normal tissue homogenates did not.

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PubMed1972

Abortive infection of human diploid cells by murine cytomegalovirus.

Inoculation of human diploid cells (WI-38) with murine cytomegalovirus (MCMV) did not result in the synthesis of any infectious virions. However, morphological changes typical of the cytopathic effects (CPE) of MCMV were detectable within 12 hr of infection. The CPE included rounding, swelling, and detachment of cells. The nuclei of infected cells were enlarged, and intranuclear inclusions were visible by May Grunwald-Giemsa staining and by the indirect fluorescent-antibody test. All cells infected at a multiplicity of infection of 3 showed CPE, and these cells could not be passaged successfully. Cell lysates and exhausted media from infected WI-38 cultures did not produce any CPE in WI-38 cells. The virus absorbed to WI-38 cells with the same efficiency as to mouse embryo fibroblast cells (MEF). Samples of MCMV in which virus infectivity for MEF cells had been inactivated by ultraviolet irradiation or by exposure to 56 C failed to produce any of the above signs. MCMV-specific CPE did not occur in the presence of actinomycin D (1 mug/ml) or puromycin (20 mug/ml), but 5'-fluoro-2'-deoxyuridine at 1 x 10(-4)m did not prevent CPE or the development of intranuclear inclusions.

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PubMed1971

Growth of murine cytomegalovirus in various cell lines.

Murine cytomegalovirus (MCMV) was capable of infecting and replicating in both primary and continuous cell lines obtained from various species. In African green monkey kidney (BSC-1) cells, primary rabbit kidney cells, and baby hamster kidney (BHK-21) cells, there were cytopathic effects (CPE) and virus replication upon initial exposure of cells to virus. In primary fetal sheep brain (FSB) cells, L cells, and rabbit kidney (RK-13) cells, it was necessary to subculture the infected cells one or more times before appearance of CPE and replication of virus. In the case of the infected FSB cultures, it was found that the virus effect could be induced if subculturing were accomplished by trypsinization but did not occur if cells were subcultured by scraping. FSB-grown virus replicated better in FSB than in mouse embryo fibroblast (MEF) cells. The CPE produced in all of the above cell lines was similar to that observed in MEF infected with MCMV. The virus grown in different cell lines was completely neutralized when mixed with several reference sera prepared in rabbits or mice. The populations of virions released from infected MEF and FSB cells were compared by isopycnic centrifugation in potassium tartrate, and no differences were revealed in the buoyant densities of the populations. Human embryonic brain cells, human embryonic kidney cells, a human lung fibroblast cell strain (WI-38), HeLa, and Hep-2 were not susceptible to MCMV.

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