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Biomedical subjects

R I Carp

Publications and source records attributed to R I Carp.

At least 109 records · Page 6Linked to original sources
PubMed1982

Retinal damage in scrapie mice.

Retinal damages in mice infected with scrapie are reported. The effects ranged from no histopathological changes, through partial loss of the outer nuclear layer (ONL) to the most severe changes with complete loss of ONL cells and photoreceptors. For the most part, cells of inner nuclear and ganglion layers were spared. These changes were found in 23% of C57BL/6J mice injected with the ME7 strain of scrapie and in 28.5% of VM mice injected with the 87 V strain, while no changes were found in 13 IM mice injected with the 87 V strain of scrapie. The possible relation of these changes to scrapie infection and to light induced retinopathy is discussed.

Animals↗
PubMed1982

Effect of mouse peritoneal macrophages on scrapie infectivity during extended in vitro incubation.

Mouse peritoneal macrophages were exposed to scrapie (ME7 strain) brain homogenate in vitro for 2 h at 37 degrees. The samples were assayed for infectivity by analysis of scrapie incubation periods and their values compared to those obtained after extended (1-28 days) in vitro incubation. The scrapie incubation periods for scrapie agent-macrophage mixtures which had undergone extended in vitro incubation were longer than for mixtures assayed after a 2-hour exposure to the scrapie agent. The difference in scrapie incubation periods was more dramatic when residual scrapie was eliminated by washing the cells after the 2-hour exposure to brain homogenate. The scrapie incubation period also increased following in vitro incubation of ME7 in the absence of cells; however, the changes were less than those observed for scrapie agent-macrophage mixtures. In a culture in which cells had been destroyed by UV irradiation after exposure to the scrapie agent, there was more scrapie infectivity than in a comparable culture of untreated, scrapie-exposed macrophages. These results show that scrapie infectivity decreases with extended incubation of scrapie-exposed macrophages, and the data suggest that macrophages can inactivate the scrapie agent in vitro.

Animals↗
PubMed1981

Persistent infection of human lymphoid cells with poliovirus and development of temperature-sensitive mutants.

Exposure of several spontaneously transformed human lymphoid cell lines to attenuated and virulent types 1 and 2 poliovirus strains led to an initial sharp increase in virus titer followed by a persistent infection. Virus was present as late as 80 passages after infection. The morphology, cell count and viability of virus- and mock-infected cells were similar. Approximately 1% of the cells scored as infectious centers, and the cultures could be cured by specific antiserum. Virus produced during persistent infections initiated with a virus that readily forms plaques at 40 degrees, Mahoney virus, showed an increase in temperature sensitivity and a decrease in plaque size.

Cell Division↗
PubMed1981

In vitro interaction of scrapie agent and mouse peritoneal macrophages.

Scrapie brain homogenate was mixed with mouse peritoneal macrophages in vitro. After 2 h of incubation at 37 degrees, a portion of the scrapie infectivity was associated with macrophages. In contrast, very little infectivity was associated with kidney cells that had been exposed to scrapie brain homogenate. After incubation of the scrapie brain homogenate-macrophage mixture at 4 degrees rather than 37 degrees, a reduced quantity of infectivity was associated with the macrophages. These result show that in vitro incubation, the scrapie agent was associated with macrophages, and the data suggest that phagocytic activity was involved.

Animals↗
PubMed1980

Antiviral activity of arildone on deoxyribonucleic acid and ribonucleic acid viruses.

Arildone (3 micro/ml) reduced the replication of murine cytomegalovirus, Semliki Forest virus, vesicular stomatitis virus, and coxsackievirus A9 by 64, 68, 94, and 98%, respectively. When the plaque reduction method was used to evaluate the antiviral effect for the viruses, a concentration of 3 to 5 micrograms/ml yielded a 50% reduction in plaque numbers. The effect of arildone on virus replication was greatest when the drug was present from the time of inoculation. The effectiveness decreased as the time interval from the inoculation of the virus to the addition of the drug increased. The removal of the drug from infected cells by washing readily reversed the effect, and viral replication resumed at a significant level. Infectivity of these viruses was not inactivated by the drug. Tissue culture cells used for viral growth and assay grew well in arildone (3 micrograms/ml), with cell yields that were comparable to those for cultures in the absence of drug. At 3 micrograms/ml there were minimal effects of the drug on the uptake of 3H-labeled amino acids and [3H]-thymidine into cells. Furthermore, incorporation of these precursors was not affected. However, there was a reduction in uptake of [3H]uridine into the acid-soluble pool and a concomitant reduction in incorporation into acid-insoluble counts.

Amino Acids↗
PubMed1980

Blood group frequencies in multiple sclerosis populations in the United States.

Multiple sclerosis (MS) patients (332) and controls (305) selected from Caucasian populations in the New York City area and in Tucson, Arizona, were tested for ABO blood group factors A and B, and Rh factors C, D, E, c, and e. There was no significant difference in the distribution frequencies of these factors in MS patients and controls.

ABO Blood-Group System↗
PubMed1979

Murine cytomegalovirus-induced protein synthesis.

Murine cytomegalovirus (MCMV)-induced protein synthesis in mouse embryo fibroblast (MEF) cells was studied using polyacrylamide gradient SDS gel electrophoresis and autoradiography. Synthesis of at least 14 virus induced proteins (VIPs) was consistently detected in a lytic cycle. They were designated VIPs 132, 118, 99, 98, 88, 81, 76, 74, 58, 56, 51, 38, 36 and 33 on the basis of their mol. wt. Judging from the pattern of the rate of protein synthesis, VIPs can be classified into three groups: group A VIPs were synthesized actively for a brief period of time and then their synthesis was no longer detectable. This group included two major VIPs, 98 and 88 and three minor VIPs, 58, 56 and 38. Group B VIPs 81, 74, 36 and 33 were similar to group A except that, following a brief period of active synthesis, a low level of synthesis continued during the entire lytic cycle. Group C VIPs 132, 118, 99, 76 and 51 were synthesized at low steady levels at all times after initiation and seemed to accumulate slowly. According to temporal sequences of initiation of VIP synthesis, these proteins can also be divided into three groups: immediate early, early and late VIPs. The synthesis of the immediate early VIPs 132, 98, 88, 81, 76, 74 and 38 was initiated immediately after virus infection. The early VIPs included 58, 56, 51, 36 and 33 and their synthesis was initiated from 1 to 3 h post-infection. VIPs 118, 99 and several minor VIPs were first synthesized during 12 to 13 h post-infection which corresponded to the time of initiation of virus DNA synthesis and they are classified as late VIPs. Cycloheximide reversal experiments indicated that the initiation of synthesis of early VIPs must be preceded by the synthesis of immediate early VIPs. In the presence of actinomycin D, the immediate early VIPs (0 to 1 h post-infection) were not synthesized indicating that immediate early VIPs are translated from virus mRNA synthesized after virus infection.

Animals↗
PubMed1978

Inactivation of cytomegalovirus and Semliki Forest virus by butylated hydroxytoluene.

Butylated hydroxytoluene (BHT) is an antioxidant that is widely used in foods because it prevents spoilage by delaying degradation of lipid components. This hydrophobic compound inactivated human and murine cytomegalovirus (CMV) and Semliki Forest virus (SFV). Both human and murine CMV were inactivated more than 90% by 40 microgram of BHT/ml after incubation for 1 hr at 37 C. Under the same conditions, SVF was inactivated about 75%, whereas poliovirus, which does not contain lipid membrane as a part of its structure, was not inactivated at all. Vaccinia virus was less sensitive to BHT than was CMV or SFV.

Animals↗
PubMed1977

Complement-fixing antigen of human cytomegaloviruses.

The titer of complement-fixing (CF) antigen of human cytomegalovirus (CMV) strain C87 was not reduced by 10 cycles of freezing and thawing or by storage at 4 C for two months, although the virus was labile at 37 C and 100 C. The rapid increase in titers of CF antigen and plaque-forming units was seen from days 3 through 6 after infection; however, CF antigen was detected 24 hr after infection. The molecular weight of CF antigen was estimated by gel filtration to be greater than 1.5 X 10(7) daltons. Electrophoresis of CF antigens from five strains of human CMV (AD169, C87, Espilant [Esp.], Davis, and Towne) in a gradient polyacrylamide gel slab in the presence of sodium dodecyl sulfate revealed two specific polypeptides with molecular weights of 140,000 and 66,000 daltons, respectively. The smaller polypeptide was glycosylated. Preparations of CF antigen from murine CMV and herpes simplex virus type 1 contained polypeptides of 140,000 and 145,000 daltons, respectively. However, the polypeptide with a molecular weight of 66,000 daltons was seen only in preparations of human CMV.

Animals↗
PubMed1976

Scrapie in vitro: agent replication and reduced cell yield.

Exposure of PAM cells, a spontaneously transformed mouse cell line, to brain homogenates from mice infected with scrapie caused a relative decrease in total cell yield, which persisted from passage 2 or 3 to passage 18 after treatment. The effect was elicited by each of the eight independent scrapie isolates tested. Lysates prepared from cultures 16 passages after treatment with scrapie caused the decrease when applied to fresh PAM cultures. Mice inoculated with passage 14 and 18 lysates developed a reduced percentage of polymorphonuclear neutrophils by 5 weeks and scrapie disease by 6 to 9 months after inoculation. Based on the total dilution from treatment of the PAM cultures with scrapie material to the preparation of the lysates, we conclude that the agent(s) responsible for the reduced PAM cell yield, the decreased percentage of polymorphonuclear neutrophils, and the induction of scrapie disease had replicated in the PAM cells. By filtration, the diameter of the agent causing the reduction in cell yield was estimated to be between 25 and 50 nm.

Animals↗
PubMed1976

Analysis of structural proteins of purified murine cytomegalovirus.

Murine cytomegalovirus propagated in mouse embryo fibroblasts was purified by the following procedures. (i) Extracellular virus was concentrated by centrifugation at 100,000 x g for 90 min. (ii) The concentrated virus was passed through a Bio-Rad Bio-Gel A-15m column to eliminate contaminating materials smaller than 15 x 10(6) daltons. Most of the virus was recovered in the void volume of the column. (iii) Two consecutive centrifugations through 20 to 50% potassium tartrate gradients were performed. After the second tartrate gradient centrifugation, symmetrical, coinciding peaks of plaque titer, protein, and radioactivity were found at a density between 1.20 g/cm3 and 1.21 g/cm3. To establish purification criteria, virus was purified from two different mixtures: [35S]methionine-labeled extracellular virus, mixed with an equal volume of unlabeled normal culture fluid, and unlabeled extracellular virus mixed with an equal volume of [35S]methionine-labeled normal culture fluid. At the end of the procedure, the extent of purification, as judged by the ratio of cellular to viral radioactivity was at least 70-fold. Virus proteins were analyzed by electrophoresis on a 5 to 20% gradient polyacrylamide gel slab. After gel electrophoresis,, Coomassie brilliant blue staining profiles and autoradiograms of the purified virus preparations were compared. At least 33 virus structural protein bands were present. The molecular weights of these proteins ranged from 11,500 to 255,000. The sum of the molecular weights of the virus structural proteins was 2,462,000. Autoradiograms obtained from electrophoresis of purified [14C]glucosamine-labeled virus showed that at lease 6 of the 33 viral structural proteins were glycoproteins.

Centrifugation, Density Gradient↗
PubMed1976

Analysis of structural polypeptides of purified human cytomegalovirus.

Human cytomegalovirus strain C87 was purified by the following procedures. (i) Extracellular virus was concentrated by centrifugation at 100,000 X g for 90 min and passed through a Bio-Rad Bio-Gel A-15m column. Most of the virus was recovered in the void volume. (ii) After two consecutive isopycnic potassium tartrate gradient centrifugations (20 to 50%), coinciding peaks of plaque titer, protein, and radioactivity were found at a density of from 1.20 to 1.21 g/cm3. To characterize the structural polypeptides of human cytomegalovirus and to establish relative purification criteria, virus was purified from two mixtures: (i) [35S]methionine-labeled extracellular virus mixed with an equal volume of unlabeled normal culture fluid; (ii) unlabeled extracellular virus mixed with an equal volume of [357a1methionine-labeled normal culture fluid. The extent of purification, as judged by the ratio of cellular to viral radioactivity, was 39-fold; i.e. about 2.5% of the protein in the purified virus preparation could be accounted for by host protein contamination. Electrophoresis of purified [35S]methionine-labeled virus on a polyacrylamide gel slab showed that there were at least 33 viral structural polypeptides (VPs), and their molecular weights ranged from 11,000 to 290,000. Autoradiograms obtained from electropherograms of purified [14C]glucosamine labeled virus showed six bands. Four of these were so broad that several VPs corresponded to each of the glycosylated bands. When heavy (two fractions close to 1.21 g/cm3) and light (two fractions close to 1.20 g/cm3) fractions of the PFU peak from the second potassium tartrate gradient were analyzed separately, the number of polypeptides observed was the same, but the relative amounts of some polypeptides differed. The major polypeptide, VP17, was found in greater amounts in the heavy fraction (35%) than in the light fraction (22%). The amount of DNA as a percentage of the weight of protein was 2% for the light fraction and 1% for the heavy fraction.

Cytomegalovirus↗