A novel gold marker to aid intraoperative localisation during spinal surgery!

Methods of pre-operative level marking for spinal surgery include fiducial implants, coil implants, spinal needle implant, methylene blue and cement injection. We describe a novel gold marker used for preoperative spinal marking and report our experience.The notes and scans of patients who had gold marker for preoperative spinal marking over the period from June 2016 to November 2018 were analysed.20 patients had preoperative spinal marking using the gold marker. The accuracy was 100% and there were no complications. Compared to injecting cement, we save over £700 per patient!

Geographical distribution of genotypic and phenotypic markers among Bacillus anthracis isolates and related species by historical movement and horizontal transfer.

The geographical distribution of Bacillus anthracis strains and isolates bearing some of the same genetic markers as the Amerithrax Ames isolate was examined and evaluated. At least one mechanism for the horizontal movement of genetic markers was shown amongst isolates and closely related species and the effect of such mixing was demonstrated on phenotype. The results provided potential mechanisms by which attempts to attribute isolates of Bacillus anthracis to certain geographical and isolate sources may be disrupted.

Basis for the extraordinary genetic stability of anthrax.

Over 500 isolates of anthrax bacillus from around the world represent one of the most genetically homogeneous microbes. There are three possibilities for this genetic stability: (1) anthrax has an extraordinarily high fidelity repair system, (2) genetic damage to anthrax is usually lethal, and/or (3) a highly demanding and selective process exists in its environment that is necessary for the completion of its life cycle. Using probes made from genes selected by growth of an Escherichia coli expression vector Bacillus anthracis library on hypertrophic high nitrate concentration medium, genes unique to B. anthracis were isolated. High nitration conditions generated stable chromosomal mutants that displayed altered morphology and life-cycle progression. Therefore, life-cycle progression connected to nitration, associated with host inflammatory response, selects for mutants that show life-cycle progression tightly coupled to progression of the inflammatory response to anthrax. Significant variation from this coupled progression leads to failure of anthrax to complete its life-cycle at the death of its host.

Response of the ke test to NCI/NTP-screened chemicals. II. Genotoxic carcinogens and non-genotoxic non-carcinogens.

A physico-chemical carcinogen-screening test was used to measure the rate constants of electron attachment, kes, of 105 chemicals that had been screened in long-term rodent bioassays and short-term in vitro tests by the NCI/NTP. In the ke test, a pulse-conductivity technique is used to generate and monitor the decay of excess electrons that serve as nucleophilic surrogates for the target tissue of rodents. Of the 61 chemicals that had been found to be rodent carcinogens as well as Salmonella mutagens, 36 yield kes that are equal to or greater than the diffusion-controlled ke of carbon tetrachloride and are considered to be positive ke test responses. In contrast, 29 of the remaining 44 chemicals that are putative non-carcinogens and non-mutagens yield kes that are negative ke test responses. These results are combined with the ke responses of 46 non-mutagenic carcinogens and 20 mutagenic non-carcinogens that were reported earlier and are evaluated to determine the degree to which the measure of electron-accepting capacity that ke provides complements or overlaps the electrophilicity or DNA reactivity of chemicals that is indicated by positive mutagenicity responses in the Ames Salmonella tester strains or by positive structural alerts, S/As, of the chemicals. The combined ke test results indicate that the overall predictivity of the ke test is comparable to and complements the Ames Salmonella test and S/As in identifying rodent carcinogens. Moreover, the electrons serve as non-discriminate nucleophilic targets for both genotoxic and non-genotoxic electron-accepting molecules and appear to attach with equal efficiency to carcinogens that are active in various tissues of rodents. This property of excess electrons suggests that the predictivity of the ke test could be enhanced by combining the measured ke with an appropriate lipophilicity or pharmacokinetic parameter. A pre-chemical electron-transfer step that had been proposed to precede chemical interactions between the carcinogen and target tissue is discussed in light of recent developments in electron-donor/-acceptor chemistry and in the application of structure--activity relationships to identify carcinogens.

Prospective ke screening of potential carcinogens being tested in rodent bioassays by the US National Toxicology Program.

Values of ke, the rate constant of electron attachment, were measured in cyclohexane for 31 of 44 chemicals now being screened for carcinogenicity in rodent bioassays conducted by the US National Toxicology Program (NTP). These kes provide a physico-chemical measure of electron-solute interaction in a non-polar medium which had been found to be correlated with solute carcinogenicity in our earlier studies of the kes of chemical carcinogens and putative noncarcinogens. The ke test yields 15 negative and 16 positive responses for the 31 chemicals that were screened in this study. These ke results are compared with the predictions of other carcinogen-screening methods that have been applied to the same chemicals and also reported in this Discussion Forum.

Response of the ke test to NCI/NTP-screened chemicals. I. Non-genotoxic carcinogens and genotoxic non-carcinogens.

The response of a physico-chemical carcinogen-screening test, the k(e) test, to 46 rodent carcinogens and 20 putative non-carcinogens that had been screened in long-term two-species bioassays by the National Cancer Institute/National Toxicology Program are reported. All of the chemicals screened are those that yield mutagenicity responses in the Ames Salmonella/microsome test that are either equivocal or contrary to the rodent carcinogenicity responses. The electron attachment rate constants, k(e)S, of the test chemicals in cyclohexane at 21 degrees C were measured using a pulse-conductivity technique. The k(e)S of 27 of the 46 rodent carcinogens (59%) are equal or greater than the diffusion-controlled k(e) of carbon tetrachloride, which is regarded as the boundary between a positive and negative response; the k(e)S of 8 of the 20 mutagenic non-carcinogens (40%) are less than diffusion-controlled. If the boundary between positive and negative k(e) responses is decreased to half the diffusion-controlled k(e), six additional carcinogens yield a positive ke response which increases the k(e) test sensitivity to 72% while the specificity to non-carcinogens remains at 40%. Comparison of these k(e)S with measures of the chemicals' electrophilicity that had been inferred from chemical structure indicates that k(e) provides a markedly different measure of electrophilicity and one that complements the Ames Salmonella assay. The use of the k(e) test as an analytical tool to indicate the presence of electron-attaching impurities in solvents such as benzene is discussed, as is the sensitivity of the k(e) test to rodent-liver carcinogens.

Isolation and characterization of the recA gene of Bordetella pertussis.

This report describes the detection and cloning of the Bordetella pertussis recA gene. Escherichia coli clones having recombinant plasmids containing the B. pertussis recA gene were isolated by complementing an E. coli RecA- mutant's inability to survive in the presence of methylmethanesulphonate (MMS). This gene was shown to complement the deficiency of E. coli RecA- strains to tolerate the DNA-damaging effects of both a chemical agent and ultraviolet light (u.v.). Deletion mapping experiments localized the gene to a 2.5 kb StuI-EcoRI fragment, and expression of the gene in E. coli resulted in the production of a 40 kD protein. These data strongly suggest that a region of the B. pertussis chromosome that encodes RecA-like activity has been isolated and cloned.

A physico-chemical screening test for chemical carcinogens: the ke test.

A pulse-conductivity technique was used to measure the rate at which excess electrons in liquid cyclohexane attach to carcinogens and non-carcinogens in order to determine if the electron attachment rate constant, ke, could be used to screen potential carcinogens. The keS of 114 chemicals are reported; these chemicals are among 182 that had previously been tested in a validation study of several short-term carcinogen-screening bioassays. The remaining 68 chemicals for which keS were not measured include chemicals that were unavailable, were not sufficiently stable or soluble in cyclohexane, or did not have a well-defined mol. wt. For the 114 chemicals that were tested, 35 are carcinogens, 50 are putative non-carcinogens and 29 have not been adequately tested or yielded equivocal responses in animal-test studies. Diffusion-controlled keS were measured for 27 of the 35 carcinogens tested whereas the keS of 45 of the 50 non-carcinogens were less than diffusion controlled. From these results, several measures of the predictive performance of using a diffusion-controlled ke to indicate a positive response to a carcinogen were calculated and compared with the Ames-test predictiveness in screening the same chemicals. The predictive criteria calculated were sensitivity, specificity, accuracy and predictive value, all of which were greater for the ke test than for the Ames test. Comparisons of the chemicals that yielded false-negative responses in the ke and Ames tests indicate a high degree of independence between the two which implies that the tests could be efficaciously used in a battery of short-term tests. Rationales are offered concerning the observed ke--carcinogenicity correlation and the apparent lack of the need for procarcinogens to be metabolically activated to yield a positive ke response.

Quasifree electron attachment to carcinogens in liquid cyclohexane.

The quasifree electron attachment rate constant, kappa e, was measured in liquid cyclohexane at 20 degrees C for 76 chemicals that had been tested for bacterial mutagenicity in at least one of five earlier studies designed to determine the correlation between bacterial mutagenicity and animal carcinogenicity. A millionfold range of kappa e's was observed with the kappa e of 37 of 42 carcinogens being equal to or greater than the diffusion-controlled electron attachment rate constant, kappa d, of 2.9 x 10(12) M-1 s-1, whereas kappa e was less than kappa d for 30 of 34 noncarcinogens. These results yield a sensitivity of 88 percent for kappa e greater than or equal to kappa d indicating a chemical's carcinogenicity and a specificity also of 88% for kappa less than kappa d indicating a noncarcinogenic chemical. The observed quasifree electron attachment sensitivity and specificity compare favorably with previously observed Ames-test mutagenicity/carcinogenicity correlations which suggests that kappa e measurements also may be of value in a carcinogen-screening program.

The development of preschool children of heroin-addicted mothers: a controlled study.

Disturbances of growth and behavior in infants and toddlers of women addicted to heroin during pregnancy have been reported in uncontrolled studies. In this study, 3- to 6-year-old children of heroin-addicted mothers were compared to three other groups matched for age, race, sex, birth weight, and socioeconomic status. Heroin-exposed children weighed less and were shorter than those in the comparison groups; 14% had a head circumference below the third percentile. Heroin-exposed children were rated by parents as less well adjusted than control children and they differed significantly in perceptual measures and on subtests of the Illinois Test of Psycholinguistic Abilities and McCarthy Scales of Children's Abilities relating to the process of organization. These findings suggest that chronic intrauterine exposure to heroin may affect growth and behavior as well as perceptual and learning processes in preschool children.

A phase II study of triazinate (NSC 139105) in advanced colorectal carcinoma.

Triazinate (Baker's Antifol, NSC 139105) was given to 28 patients as a single agent in the chemotherapy of advanced colerectal carcinoma. The dosage utilized was 250 mg/m2 intravenously, administered daily in three consecutive days. Patients were evaluated at three weeks, six weeks, and then monthly until progression was evident. Various immunologic determinants (i.e., DNCB sensitization, immunoglobulins, recall skin tests, lymphocyte blastogenesis, and circulating lymphocytes, T-cells and B-cells) were obtained prior to treatment and at each re-evaluation. The principal side effects were dermatitis, stomatitis, diarrhea, nausea, somnolence, and leukopenia. There was no discernable effect of Triazinate on the immunologic determinants tested. There was one complete response, and four partial responses, for an objective regression rate of 18%. This study suggests that Triazinate has a definite, though limited, effect on advanced colorectal carcinoma.