[Aneurysm surgery in the older patients (author's transl)]

A series of 9 patients over 70 years of age with saccular aneurysms, operated on by a direct surgery is reviewed in order to discuss the aneurysm surgery in the older patients. The median age of the patients was 74 years, and median interval from the hemorrhage to surgery was 18 days. Operative mortality was 11% and morbidity was 33%. Result of intracranial aneurysm surgery in the older patients depends on the surgical technique for the arteriosclerosis. 1. Treatment of the aneurysm neck must be abandoned when a severe arteriosclerosis exists around it. Subsequent to exposure of the whole aneurysm, a complete reinforcement of the aneurysm wall should be undertaken. 2. Especially gentle manipulation of the brain is necessary since small arteries are easily pulled out from the sclerotic artery. 3. The cerebral veins must be preserved as well as possible to avoid the venous congestion, which easily causes an intracerebral hematoma following brain retraction. 4. The frequency of pre and postoperative complications is high, but through vigorous care, they are kept under control. 5. It is best not to judge the surgical indication simply by the chronological age, but rather to consider the physical age including the laboratory findings. Therefore, other than cases of severe arteriosclerosis, the same principles for surgical indication in younger patients should be used for older patients.

[Anterior communicating artery aneurysms accompanied with anomalies or anterior communicating artery (author's transl) ]

The investigation was carried out on arterial anomalies complicated with 296 cases of single aneurysm of anterior communicating artery and on the etiological significance of the anomalies in the development of cerebral aneurysms. Either the fenestration in anterior communicating artery or the presence of more than 2 anterior communicating arteries was observed in 17 cases (5.7%). As the anomaly was duplicated in some of these cases, the total number of cases with anomalies of anterior communicating artery became to be 26 cases (8.8%) out of 296 cases investigated. This occurrence rate was not higher than those observed in other cerebral aneurysmal cases and the control cases, which were reported previously. There was no significant difference as to the occurrence rate of hypoplasia of the A1 portion between the cases whose aneurysms of anterior communicating artery were complicated with arterial anomalies and the cases without the arterial anomalies.

Effects of hydroxyurea on murine type C virus-specific DNA synthesis in newly infected cells

Cell transformation and replication of the Rauscher pseudotype of Moloney murine sarcoma virus in mouse embryo fibroblasts were inhibited by hydroxyurea within a critical time period of 30 to 90 min postinfection. In cells infected by Rauscher leukemia virus, treatment with 1mM hydroxyurea during the critical time period resulted in the accumulation of minus-strand DNA (molecular weight, 3 x 10(6)) in association with the parental viral genoma RNA. This 5 to 6 x 10(6) dalton RNA:DNA hybrid was found in the cytoplasm. Positive-strand DNA of genomic or smaller size was not detected in the presence of hydroxyurea, but virus-specific DNA was found in the nucleus 30 min after removal of drug.

Reiteration frequency of feline type C viral genomes in homologous and heterologous host cell DNA

Differences in the multiplicity of proviral sequences of two feline endogenous viruses, RD-114 and FeLV, in homologous and heterologous host DNA were examined by viral cDNA hybridization using cellular DNA fractionated with respect to reiteration frequency. The endogenous proviral DNAs in cat cells were fractionated predominantly with intermediate-repeated sequences, while RD-114 proviral DNA in virus-infected human cells was fractionated together with unique-sequence DNA. These differences were consistent with the results of kinetic analysis using unfractionated DNA.

Uracil phosphoribosyl transferase activity of mycoplasma and infected cell cultures

Human H.Ep-2 and mouse 3T6 cells infected by Mycoplasma hyorhinis showed an increase in [3H]uracil uptake and a more than 20-fold increase in the activity of uracil phosphoribosyltransferase (UraPRT). Uninfected cell cultures gave background levels of this enzyme activity. A survey of 16 strains of mycoplasma showed 13 to possess UraPRT activity. Rabbit kidney cells (RK13) were infected with eight different strains of four mycoplasma species known to be common cell culture contaminants. Seven of the eight cell cultures showed elevated UraPRT activities four days after infection. This enzyme activity may be of value in monitoring cell cultures for mycoplasma and aid in classification.

Electron microscopic studies of circular DNA in mouse embryo fibroblasts infected by Rauscher leukemia virus

Using electron microscopy, a closed circular form of DNA (4.3 mum in contour length) was detected in the nucleus of mouse embryo fibroblasts 2.5 h after infection by Rauscher murine leukemia virus. These circles were distinguishable from mitochondrial DNA by various criteria, including size, absence of secondary features, and resistance to EcoRI endonuclease.

Saturable and nonsaturable process of sugar uptake: effect of oncogenic transformation in transport and uptake of nutrients

Uptake of sugars into cells by a saturable process increased enormously during and after transformation, and uptake by a nonsaturable process increased significantly but less remarkably compared to controls. The drastic change of uptake rates, observed at around 5 x 10(-3) M sugar during and after transformation, emphasizes the significant observation that transition of the sugar uptake system from a saturable to a nonsaturable process occurs near the physiological concentration of D-glucose normally seen in animal blood. At concentrations below higher than 5 x 10(-3) M, where a saturable process is barely involved, nonsaturable uptakes of D-glucose, D-mannose, D-galactose, 2-deoxy-D-glucose and 3-O-methyl-D-glucose proceed tens to hundreds fold faster than the rate of simple diffusion of L-glucose. These findings suggest that nonsaturable uptake of the sugars known to be substrates for the saturable transport carrier system may not be a physical process or simple diffusion, as observed for L-glucose uptake. Rather, the nonsaturable uptake might be part of the total physiological process which, along with the saturable process, is controlled by a membrane-coordination mechanism. A plausible mechanism is discussed in which negative cooperativity of nutrient uptake, such as that found in bacteria, is involved.

Size of virus-specific RNA in B-34, a hamster tumor cell producing nucleic acids of type C viruses from three species

B-34 is the designation of a hamster tumor-derived cell line induced by the Harvey sarcoma virus. This cell line produces virions which contain structural proteins common to edogenous hamster viruses and nucleic acid sequences of hamster, mouse, and rat origin. The sedimentation characteristics of the intracellular virus-specific RNA was determined in sucrose gradients after treatment with dimethylsulfoxide by molecular hybridization using complementary DNA of strict virus specificity. Hamster virus-specific RNA sedimented at 35S (major peak) as is characteristic of productive infection by type C leukemia viruses of other species. Rat virus-specific RNA sedimented at 30S which is characteristic of the sarcoma virus-related genome found in nonproducer cells transformed by Kirsten sarcoma virus. Both Harvey and Kirsten sarcoma viruses contain a related but not necessarily identical 30S rat-specific component which is also found in normal cultured rat cells. Mouse cells producing Harvey sarcoma virus also contain a rat-specific 30S RNA. Mouse virus-derived sequences also sedimented at 30S in B-34 cells and in a similar size range in Harvey virus-infected mouse cells. The possibility that the mouse and rat-derived sequences are present on a single 30S RNA species which would then be related to sarcomagenic potential is one attractive hypothesis suggested by these data.

Kinetics of murine type C virus-specific DNA synthesis newly infected cells

Replicating transforming functions of Rauscher leukemia virus (RLV) and the RLV pseudotype of Moloney sarcoma virus in mouse embryo fibroblasts were found to be most sensitive to inhibition by cytosine arabinoside (ara-C) 30 to 90 min after infection. The initiation of intracellular RLV DNA synthesis was detected by nucleic acid hybridization within this time interval. Treatment of infected cells with cytosine arabinoside abolished RLV DNA synthesis. Peak synthesis of the DNA complementary to the infecting RLV genome, the (-) strand, occurred 40 to 60 min after infection. During this interval two s two species of DNA were observed with estimated molecular weights of 0.5 X 10(5) to 1.0 X 10(5) and 3 X 10(6). Peak synthesis of the (+) strand viral DNA occurred 50 to 70 min after infection. The initial species detected had a molecular weight of 1.5 X 10(5) to 4.0 X 10(5) which shifted as a function of time to 3 X 10(6). Both (+) strand species were initially detected in the cytoplasm followed by a rapid (10-min interval) appearance of the faster-sedimenting species in the nucleus. The virus-specific (-) and (+) strand DNA species are presumably unintegrated intermediates in provirus formation.

Murine sarcoma virus related nucleic acid sequences in a non-transforming virus derived from an interspecies pseudotype sarcoma virus

A number of sarcomagenic viruses recovered from hamster tumors induced originally by Moloney sarcoma virus or several of its mouse pseudotypes appear to be interspecies pseudotypes with structural proteins of hamster type-C viruses and nucleic acid sequences of both mouse and hamster specificity. A non-transforming virus (GLOH-minus) recovered from a sarcomagenic virus preparation obtained from a tumor induced by the Gross pseudotype of Moloney sarcoma virus was previously shown to retain mouse sequences. The ability to discriminate readily between Gross and Moloney viruses by molecular hybridization, especially with regard to thermal stability of inter-strain hybrid molecules, and the stability of Moloney virus sequences in a rat-mouse interspecies pseudotype, made it possible to specify that the mouse virus-specific sequences in GLOH-minus are derived from Moloney virus and not Gross. Thus, even though GLOH-minus is non-transforming in vitro or in vivo, it still retains sequences highly related to Moloney sarcoma virus. The lack of transforming ability is thus probably based on loss or change of specific sequences necessary for transformation at some point in the history of this virus.

Effect of UV Light on RNA-Directed DNA Polymerase Activity of Murine Oncornaviruses

The UV inactivation of RNA-directed DNA polymerase activity of Rauscher leukemia virus was shown to be due to damage to the protein. The UV dose resulting in 37% survival of viral polymerase activity at 254 nm was 2.4 × 10 4 to 3.1 × 10 4 ergs/mm 2 . The inactivation rate of p30, a major internal viral protein, was much slower.

Adenine formation from adenosine by mycoplasmas: adenosine phosphorylase activity

Mammalian cells have enzymes to convert adenosine to inosine by deamination and inosine to hypoxanthine by phosphorolysis, but they do not possess the enzymes necessary to form the free base, adenine, from adenosine. Mycoplasmas grown in broth or in cell cultures can produce adenine from adenosine. This activity was detected in a variety of mycoplasmatales, and the enzyme was shown to be adenosine phosphorylase. Adenosine formation from adenine and ribose 1-phosphate, the reverse reaction of adenine formation from adenosine, was also observed with the mycoplasma enzyme. Adenosine phosphorylase is apparently common to the mycoplasmatales but it is not universal, and the organisms can be divided into three groups on the basis of their use of adenosine as substrate. Thirteen of 16 Mycoplasma, Acholeplasma, and Siroplasma species tested exhibit adenosine phosphorylase activity. M. lipophilium differed from the other mycoplasmas and shared with mammalian cells the ability to convert adenosine to inosine by deamination. M. pneumoniae and the unclassified M. sp. 70-159 showed no reaction with adenosine. Adenosine phosphorylase activity offers an additional method for the detection of mycoplasma contamination of cells. The patterns of nucleoside metabolism will provide additional characteristics for identification of mycoplasmas and also may provide new insight into the classification of mycoplasmas.

Type-C virus-specific nucleic acid sequences in cultured rat cells

Single-stranded DNA transcripts of rat type-C viruses prepared in the presence of actinomycin D, hybridized specifically to DNA of several rat cell cultures with no obvious qualitative or quantitative differences. Similar products prepared from a pseudo-type sarcoma virus with contributions from rat and mouse type-C viruses hybridized to both rat and mouse cellular DNA, while mouse viral transcripts did not hybridize to rat cell DNA. Viral RNA was detected in all rat cells by means of the rat viral DNA transcripts, with some differences between untreated low-passage cells and sister cultures treated with bromodeoxyuridine or bromodeoxyuridine and methylcholanthrene. Cells treated with both compounds were previously shown to be transformed and turorigenic, and these were distinguishable by kinetic analysis from the control cells.

Fate of viral RNA of murine leukemia virus after infection

[3H]Uridine-labeled Rauscher leukemia virus was used to infect mouse embryo fibroblasts. After the infected cells were separated into nuclear and cytoplasmic fractions nucleic acid was extracted by sodium dodecyl sulfate-phenol-chloroform treatment and analyzed by Cs2SO4 and sucrose density gradient centrifugation. Between 45 and 70 min after infection a transient and synchronized shift of the acid-insoluble radioactive peak toward the RNA-DNA hybrid region occurred in both the nuclear and cytoplasmic fractions. The density of the cytoplasmic hybrid shifted to 1.56 g/ml (RNA equals about 50%), while the sedimentation rate decreased from 36 S to 14 S; however, the density of the nuclear hybrid shifted to 1.58-1.48 g/ml (RNA equals 57-17%, respectively), while its sedimentation rate remained about 65 S. The hybrids in both the nuclear and the cytoplasmic fractions still showed hybrid density after heat denaturation. The processes of the early stages of RNA tumor virus infection are discussed with regard to the functions of viral RNA-dependent DNA polymerase (reverse transcriptase) and a possible integration of viral genetic information into the host chromosome.

Sarcoma-virus-related RNA sequences in normal rat cells

A rat type C virus spontaneously activated from the NRK (normal rat kidney) cell line was found to have two major size classes of viral RNA subunits sedimenting at 35 and 30 S. Virus-producing cells contained both RNA species, while normal "virus-free" rat cells contained primarily virus-specific 30S RNA species. A DNA transcript, specific for Kirsten sarcoma virus, prepared from virus activated in nonproducer BALB/c cells originally transformed by Kirsten sarcoma virus and rendered specific for the virus by absorption of sequences related to mouse helper virus hybridized only with the 30S RNA species of virus-producing rat cells and normal rat cells. These findings are consistent with the hypothesis that sarcoma-specific nucleic acid sequences in kirsten sarcoma virus emerged through a process that incorporated some portions of 30S RNA species from rat cells (either normal or virus-producing) into the Kirsten leukemia virus during passage in vivo of that virus. The virus designated M-MSV(RaLV), which originally derived from tumor induced by Moloney sarcoma virus (M-MSV) in rats, contained 35S RNA species of rat type C viruses and 30S RNA species specific for both rat and mouse viruses. It appears striking that for these two animal species, sarcoma-virus-specific information resides on a 30S subunit.

Sarcoma and helper-specific RNA tumor virus subunits in transformed nonproducer mouse cells activated to produce virus by treatment with bromodeoxyuridine

A tumor line (58-2T) was established from a slowly growing tumor in a BALB/c mouse inoculated with M58-2 cells. The latter clonal cell line was isolated after bromodeoxyuridine treatment as a flat variant from nonproducer BALB/3T3 cells transformed by the Kirsten sarcoma virus. The 58-2T cells produced type C virus with two discrete virus-specific RNA species. One of the species, which was probably an endogenous virus RNA subunit, had a sedimentation coefficient of 35S as the largest major subunit, and had sequences similar to Rauscher leukemia virus RNA based on nucleic acid hybridization. The other RNA species had 30S as the largest major subunit and corresponded to Kirsten sarcoma virus-specific RNA. These two RNA species formed heterogeneous, 60 to 70S, high-molecular-weight RNA in virions.DNA transcripts (58-2T DNA) from the activated virus contained base sequences complementary to Rauscher leukemia virus and Kirsten sarcoma virus. The Kirsten sarcoma virus-specific DNA sequences (58-2TS) were purified from 58-2T DNA by eliminating RLV-specific sequences.

Specificity of the DNA product of RNA-dependent DNA polymerase in type C viruses: 3. Analysis of viruses derived from Syrian hamsters

DNA transcripts were prepared from three related viruses of hamster and analyzed by interviral hybridization and by reaction with cellular DNA. A virus (G-HaLV), isolated from a dimethylbenzanthraceneinduced tumor cell in Graffi hamsters, contained nucleic acid sequences highly specific for hamster cell DNA and did not react with mouse cell DNA nor did its transcript show homology (<5%) with mouse or rat viral RNAs. The hamster-specific sarcoma virus, B-34, isolated by Bassin and coworkers from tumors induced by the Harvey strain of murine sarcoma virus, contained mouse-, hamster-, and possibly rat-specific sequences. B-34 transcripts were predominantly mouse-specific. GLOH(-), a lymphomagenic virus derived by dilution beyond the transforming endpoint of a hamster-specific sarcoma virus obtained from tumors induced by the Gross pseudotype of murine sarcoma virus, also contained hamster- and mouse-specific sequences. Only a portion of its hamster sequence (about 50%) was shared with B-34 and G-HaLV viruses. As expected, transcripts of GLOH(-) virus were reactive with mouse and hamster cellular DNA.