Stabilization vs. destabilization of G-quadruplex superstructures: the role of the porphyrin derivative having spermine arms.

The interaction of the porphyrin derivative H2TCPPSpm4, having spermine pendants in the four meso positions, with the G-quadruplex (GQ) structure formed by the DNA aptamer TGGGAG has been investigated by means of UV, electronic circular dichroism and PAGE studies. The results reported here demonstrate that the porphyrin derivative is capable of stabilizing or destabilizing the higher-ordered structures of parallel GQs, depending on the method used to reach their relative stoichiometry (titration vs. single addition). Noteworthily, when two equivalents of H2TCPPSpm4 were mixed directly with one equivalent of the (TGGGAG)4 GQ to reach a 2 : 1 H2TCPPSpm4 : GQ ratio T1/2 higher than 80 °C was also observed confirming the presence of higher-ordered GQ structures.

A series of cationic sterol lipids with gene transfer and bactericidal activity.

A family of cationic lipids was synthesized via direct amide coupling of spermine to the C-24 position of cholic acid analogs. Four monosubstituted spermines and a bis-substituted spermine were evaluated as plasmid transfection reagents, as bacteriostatic agents, and as bactericidal agents. The incorporation of a double bond in the sterol moiety enhanced transfection efficiency significantly and produced two compounds with little cytotoxicity and transfection potency comparable to Lipofectamine2000. Inclusion of the double bond had no effect on the general trend of increasing bactericidal activity with increasing sterol hydrophobicity. Co-formulation of the most hydrophilic of the compounds with its bis-substituted analogue led to enhancement in transfection activity. The bis-substituted compound, when tested alone, emerged as the most bacteriostatic compound in the family with minimum inhibitory concentrations (MIC) of 4 microM against Bacillus subtilis and 16 microM against Escherichia coli and therapeutic indexes (minimum hemolytic concentration/minimum inhibitory concentration) of 61 and 15, respectively. Cationic lipids can be optimized for both gene delivery and antibacterial applications by similar modifications.

Vortexes tune the chirality of graphene oxide and its non-covalent hosts.

Graphene oxide (GO) is one of the most appealing bidimensional materials able to interact non-covalently with achiral molecules and to act as chiral inducers. Vortexes can tune chirality and, consequently transfer a specific handedness to non-covalent host molecules, either when dispersed in water or when deposited on a solid surface.

Anti-inflammatory agents in experimental atherosclerosis. Part 2. Failure of antihypertensive drugs to exacerbate atherosclerotic plaque formation.

Hypertension is associated with an increased incidence of generalized vascular disease. Antihypertensive drug therapy, while decreasing overall mortality due to cerebral hemorrhage, myocardial hypertrophy or renal failure, paradoxically does not appear to reduce the incidence of coronary atherosclerosis. This study investigates whether the drugs, as a possible side effect, may have an adverse influence on the development of atherosclerotic plaques. Groups of rabbits were fed an atherogenic diet containing 1% cholesterol for 12 weeks. Two commonly used antihypertensive agents (methyldopa and chlorthalidone) were added to the diet of some groups at levels of 100 mg and 10 mg per day respectively. No significant increase in total atherosclerotic plaque area was produced by either of the drugs tested singly or in combination. Plasma renin levels were only mildly elevated and in this experimental system there was no correlation between renin activity and atherosclerotic plaque intensity. There is thus no evidence from this study that antihypertensive drugs have any adverse effects on atherosclerotic plaque formation. While the ineffectiveness of these drugs against coronary atherosclerosis may indicate that normalization of pressure cannot arrest changes already initiated, it also supports the possibility that association of atherosclerosis with hypertension may be symptomatic of a common underlying defect not correlated by normalizing blood pressure.

Anti-inflammatory drugs in experimental atherosclerosis. Part 5. Influence of cortisone acetate on short-term and long-term cholesterol fluxes in atherosclerotic aorta.

Previous studies in this series have shown that cortisone and other anti-inflammatory drugs inhibit atherosclerotic plaque development in cholesterol-fed rabbits. The present study was designed to investigate the influence of cortisone on the processes of cholesterol influx and efflux in the aorta wall. Forty-seven New Zealand white rabbits were fed a 1% cholesterol diet for periods up to 12 weeks. In addition 23 of the animals were fed 5 mg cortisone acetate daily. At 0, 5 and 12 weeks, groups were fed a tracer dose of [3H]cholesterol. Plasma cholesterol specific radioactivity was measured at intervals during the next 10 days. Total aorta cholesterol and its specific activity were measured by killing groups of animals at 2 days and 10 days. Atherosclerotic plaque intensity at 12 weeks, measured planimetrically, averaged 68 +/- 12% in controls vs. only 6 +/- 3% in cortisone-treated animals. During the period between 5 and 12 weeks, net cholesterol accumulation by chemical analysis averaged only 11 micrograms/g aorta/day in cortisone-treated animals vs. 117 micrograms/g in controls. [3H]cholesterol influx (measured during a brief 2-day exposure) at 5 weeks averaged 206 and 199 micrograms/g tissue/day and at 12 weeks 586 micrograms and 281 micrograms/day in control and cortisone-treated animals, respectively. Measured over a longer 10-day period, however, the apparent influx of [3H]cholesterol was much less in cortisone-treated animals, averaging only 53 micrograms/day compared to 269 micrograms/day in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of verapamil in reducing the severity of acute tubular necrosis in canine renal autotransplants.

Calcium channel blockade has been shown to prevent warm renal ischemic damage. The ability of verapamil to decrease the severity of acute tubular necrosis (ATN) after 24-hr cold storage and autotransplantation was studied in a randomized paired study of 12 dogs. Experimental animals pretreated with intraarterial verapamil and flushing of the harvested kidney with cold intracellular solution containing verapamil demonstrated significantly (P less than .05) greater renal function preservation over their matched controls. A subsequent nonpaired study of 6 dogs treated only with flushing of the harvested kidney with perfusate containing verapamil demonstrated no significant preservation advantage over controls. We conclude that verapamil, administered prior to the ischemic event, can enhance the protective effect of hypothermia and decrease the severity of ATN in ischemically injured kidneys.

Spontaneous perinephric hemorrhage from extrarenal angiomyolipoma.

We believe this is the first reported case of spontaneous perinephric hemorrhage arising from an extrarenal angiomyolipoma. To date there have been no cases reported of extrarenal angiomyolipoma associated with tuberous sclerosis. All extrarenal angiomyolipomas have been benign and treated with simple excision.

Renal pelvic cancer: a review of 611 patients treated in Illinois 1975-1985. Cancer Incidence and End Results Committee.

Renal pelvic transitional cell carcinoma constitutes about 7 percent of all kidney cancer. This report is a summary of 611 Illinois patients with this tumor treated between 1975 and 1985. Overall, the five-year relative survival rate was 62 percent and the observed five-year rate was 48 percent. Stage was a major determinant of survival, as expected, in these cancer patients. The Illinois experience is reviewed and compared with the accumulated literature experience with renal pelvic cancers since 1944.

Modulation of induced reversion frequency by nucleotide pool imbalance as a tool for mutant characterization.

Addition of thymidine (TdR) or deoxycytidine (CdR) to the culture medium during posttreatment incubation affected the frequency of mutagen-induced reversion in three hypoxanthine-guanine phosphoribosyl transferase-deficient mutants of V79 Chinese hamster cells. With two of the mutants (E20 and I3), reversions induced by N-ethylnitrosourea, ethyl methanesulfonate, and methyl methanesulfonate were enhanced by TdR and were either decreased (E20) or not affected (I3) by CdR. With the third mutant (E21), alkylating agent-induced reversions were enhanced by CdR and decreased by TdR. Finally, 6-amino-2-hydroxypurine induced reversions were enhanced by TdR in mutant I3 and were decreased by TdR or deoxyadenosine (AdR) and enhanced by CdR in mutant E21. An attempt was made to reconcile these results with simple mutation mechanisms, based on either G:C to A:T or A:T to G:C transitions. It is suggested that the present approach may add useful information to studies of specific revertibility of mammalian cell mutants with known mutagens.

Mutagenicity of halogenated aliphatic hydrocarbons in Salmonella typhimurium, Streptomyces coelicolor and Aspergillus nidulans.

Eight structurally related halogenated aliphatic hydrocarbons mono-, di- and trichloroacetaldehyde (the last in the anhydrous and hydrate form), moni-, di- and trichloroethanol and allyl chloride, were tested for their ability to induce gene mutations in prokaryotic and eukaryotic microorganisms. The genetic systems employed were the Salmonella reversion test with strain TA1535 and TA100, with and without metabolic activation, a forward and a back-mutation system in S. coelicolor and two forward mutation systems in A. nidulans. Each compound was tested with the spot and plate incorporation assay techniques. Mono-, di- and trichloroacetaldehyde were mutagenic in all the microorganisms employed; all the halogenated ethanols were positive in A. nidulans, while in S. typhimurium and in S. coelicolor the only active forms were respectively the mono- and dichloroderivatives. Allyl chloride was active in S. typhimurium and S. coelicolor and negative in A. nidulans. The technical approach as well as the complex influence of different factors (toxicity, volatility and stability) on the genetic response of each of the compounds under test did not allow to obtain more than a qualitative relationship between mutagenic potency and chemical structure.

Recovery of V79 cell clones with different phenotypes in aminopterin- or azaserine-containing media used for the selection of HGPRT revertants.

Three 6-thioguanine (6TG)-resistant mutants were mutagen-treated and selected for clones capable of growing in 2 selective media: HAT medium, containing aminopterin (AP) and HAS medium, containing L-azaserine (AS). Both 6TG-sensitive, wild-type clones and 6TG-resistant mutants were found among colonies growing in HAT medium, while only 6TG-sensitive clones grew in HAS medium. Time for expression was required by 6TG-resistant but not by 6TG-sensitive clones, that were fully expressed immediately after treatment. All HAT-resistant, 6TG-resistant clones which were analyzed proved to be resistant to AP. These data were interpreted as follows: in HAT medium, both HGPRT+ revertants and double mutants (HGPRT-, AP-resistant) were selected, while only HGPRT+ revertants were selected in HAS medium. Not all 6TG-resistant mutants were able to produce both classes of HAT-resistant clones.

Selection in HAT medium is not a reliable method for the study of reversion from 6-thioguanine resistance to sensitivity.

6-Thioguanine-resistant mutants were induced in V79 Chinese hamster cells with 2-aminopurine, ICR-170 and hycanthone. Samples of mutants of different origin were treated with EMS or 1CR-170 and plated in HAT medium for selection of revertants. In the result, a significant fraction of HAT-resistant clones was not 6-thioguanine-sensitive as would have been expected from a genuine reversion to wild type.

Localized mutagenesis in Streptomyces coelicolor A3 (2).

Nutritional mutants (co-mutants) were scored among nitrosoguanidine-induced revertants of four mutations in Streptomyces coelicolor A3 (2). All co-mutations were due to mutations in genes linked to the revertant locus. The co-mutant loci were located in a region of about 20 map units around the revertant locus (co-mutation region). Revertants for different loci showed co-mutation patterns different from each other and from that of random nitrosoguanidine-induced forward mutations. Mutations appeared to be completely abolished outside the co-mutation region (mutation restriction).

Chromosome aberrations associated with CAD gene amplification in Chinese hamster cultured cells.

Eleven sublines with increasing resistance to N-phosphonacetyl-L-aspartate (PALA) were isolated from the V79,B7 Chinese hamster cell line. Aspartate transcarbamylase activity and CAD gene copy number increased with increasing resistance of sublines. In situ hybridization with a DNA probe for the CAD gene showed that the amplified sequences resided in the terminal region of a marker chromosome with elongated q arms. This region stained homogeneously after G-banding. A high incidence of both numerical and structural chromosome aberrations was found in PALA-resistant cells. In hyperdiploid and polyploid cells, containing 2 copies of the marker chromosome, dicentrics were found at a very high frequency. As indicated by in situ hybridization and G-banding, they originated from a rearrangement involving 2 homologous marker chromosomes.

Comutation in Streptomyces.

Up to 6% of N-methyl-N'-nitro-N-nitrosoguanidine-induced back mutations in the hisA locus of Streptomyces coelicolor were forward mutations (comutations) in another closely linked his locus.

Plasmid-dependent co-mutation in Streptomyces coelicolor A3(2).

A spontaneous chromosomalmutation(plc A(-)) in Streptomyces coelicolor A3(2) made the inborn plasmid SCP1 susceptible to curing by UV irradiation. Lack of the SCP1 plasmid (in SCP1(-) strains) prevented the occurrence of the co-mutation process after MNNG treatment, although it left the susceptibility to the lethal effect of the mutagen virtually unaffected. SCP1(-) strains were, however, ultrasensitive to the lethal effect of UV. Curing a plc A(-) strain of its SCPI plasmid made it refractory to co-mutation by MNNG and sensitive to the lethal effect of UV; reinfected by the plasmid, the strain resumed both the co-mutation proficiency and the UV-resistance. The occurrence on the SCP1 plasmid of a gene comparable to the uvrE gene of E. coli (Nevers and Spatz 1975) was assumed.

Cytogenetic manifestations associated with the reversion, by gene amplification, at the HGPRT locus in V79 Chinese hamster cells.

Some HGPRT spontaneous revertants were isolated from a mutant line (E2) of V79 Chinese hamster cells and phenotypically characterized. Dot-Blot hybridization with a 32P-labelled HGPRT probe revealed an increase in the number of HGPRT sequences in some of these revertants, suggesting the occurrence of gene amplification. Cytogenetic analysis performed in three of these revertants showed a characteristic abnormally banding region (ABR) on the elongated p arm of the X chromosome. In situ hybridization in one revertant (RHE2) showed that the amplified sequences reside on the p+ arm of the X chromosome in two different localizations. Because of the very probably clonal origin of the revertant, these features indicate that the amplified sequences might rearrange after their integration into the chromosome.

Invasive giant condylomata acuminata: a case report.

We report on a patient with invasive giant condylomata acuminata (Buschke-Loewenstein tumor). This tumor is an exophytic human papilloma viral lesion with downward growth without histological malignancy. The aggressive progression of this lesion requires early surgical excision with clear margins. Delay in recognition of this tumor can otherwise lead to a fatal clinical course.