Evaluation of Combination Drug Therapy for Treatment of Antibiotic-Resistant Inhalation Anthrax in a Murine Model.

Bacillus anthracis is considered a likely agent to be used as a bioweapon, and the use of a strain resistant to the first-line antimicrobial treatments is a concern. We determined treatment efficacies against a ciprofloxacin-resistant strain of B. anthracis (Cipr Ames) in a murine inhalational anthrax model. Ten groups of 46 BALB/c mice were exposed by inhalation to 7 to 35 times the 50% lethal dose (LD50) of B. anthracis Cipr Ames spores. Commencing at 36 h postexposure, groups were administered intraperitoneal doses of sterile water for injections (SWI) and ciprofloxacin alone (control groups), or ciprofloxacin combined with two antimicrobials, including meropenem-linezolid, meropenem-clindamycin, meropenem-rifampin, meropenem-doxycycline, penicillin-linezolid, penicillin-doxycycline, rifampin-linezolid, and rifampin-clindamycin, at appropriate dosing intervals (6 or 12 h) for the respective antibiotics. Ten mice per group were treated for 14 days and observed until day 28. The remaining animals were euthanized every 6 to 12 h, and blood, lungs, and spleens were collected for lethal factor (LF) and/or bacterial load determinations. All combination groups showed significant survival over the SWI and ciprofloxacin controls: meropenem-linezolid (P = 0.004), meropenem-clindamycin (P = 0.005), meropenem-rifampin (P = 0.012), meropenem-doxycycline (P = 0.032), penicillin-doxycycline (P = 0.012), penicillin-linezolid (P = 0.026), rifampin-linezolid (P = 0.001), and rifampin-clindamycin (P = 0.032). In controls, blood, lung, and spleen bacterial counts increased to terminal endpoints. In combination treatment groups, blood and spleen bacterial counts showed low/no colonies after 24-h treatments. The LF fell below the detection limits for all combination groups yet remained elevated in control groups. Combinations with linezolid had the greatest inhibitory effect on mean LF levels.

Correlation of environmental carbaryl measurements with serum and urinary 1-naphthol measurements in a farmer applicator and his family.

In exposure or risk assessments, both environmental and biological measurements are often used. Environmental measurements are an excellent means for evaluating regulatory compliance, but the models used to estimate body burden from these measurements are complex. Unless all possible routes of exposure (i.e., inhalation, dermal absorption, ingestion) are evaluated, exposure to a toxicant can be underestimated. To circumvent this problem, measurements of the internal dose of a toxicant in blood, serum, urine, or tissues can be used singularly or in combination with environmental data for exposure assessment. In three separate laboratories, carbaryl or its primary metabolite, 1-naphthol, was measured in personal air, dermal samples, blood serum, and urine from farmer applicators and their families. The usefulness of both environmental and biological data has been demonstrated. For the farmer applicator, the environmental levels of carbaryl would have been sufficient to determine that an exposure had occurred. However, biological measurements were necessary to determine the absorbed dose of each member of the applicator's family. In addition, a correlation between serum and urinary 1-naphthol measurements has been shown; therefore, either matrix can be used to accurately evaluate occupational carbaryl exposure.

Levels of methyleugenol in a subset of adults in the general U.S. population as determined by high resolution mass spectrometry.

We developed a sensitive and accurate analytical method for quantifying methyleugenol (ME) in human serum. Our method uses a simple solid-phase extraction followed by a highly specific analysis using isotope dilution gas chromatography-high resolution mass spectrometry. Our method is very accurate; its limit of detection is 3.1 pg/g and its average coefficient of variation is 14% over a 200-pg/g range. We applied this method to measure serum ME concentrations in adults in the general U.S. population. ME was detected in 98% of our samples, with a mean ME concentration of 24 pg/g (range < 3.1-390 pg/g). Lipid adjustment of the data did not alter the distribution. Bivariate and multivariate analyses using selected demographic variables showed only marginal relationships between race/ethnicity and sex/fasting status with serum ME concentrations. Although no demographic variable was a good predictor of ME exposure or dose, our data indicate prevalent exposure of U.S. adults to ME. Detailed pharmacokinetic studies are required to determine the relationship between ME intake and human serum ME concentrations.

Current activities at the Centers for Disease Control and Prevention's National Diabetes Laboratory.

In 1997, the Centers for Disease Control and Prevention established the National Diabetes Laboratory in order to help prevent and treat type 1 diabetes. This state-of-the-art laboratory collaborates with research scientists and key national and international organizations throughout the world to identify and study risk factors for type 1 diabetes by developing measurements for glycosylated proteins, developing and evaluating technology for measuring genetic risk factors for the disease, and working to standardize autoantibody measurements. Developing improved technologies for diagnosing and managing diabetes and developing reference materials for properly calibrating and standardizing blood glucose meters are also critical aspects of the laboratory's work. In addition, the laboratory provides quality storage for valuable collections of biologics and other materials and facilitates sharing of specimens, associated epidemiologic data, and test results. Working with our partners in diabetes research, we are improving the diagnosis, treatment, and prevention of type 1 diabetes.

Selectivity of electron-donor- and electron-acceptor-bonded silica packing materials for hydrophobic environmental contaminants in polar and non-polar eluents.

Electron-acceptor-bonded stationary phases, 2-(nitrophenyl)ethylsilyl (NPE) and 3-(p-nitrophenoxy)propylsilyl (NPO), and electron-donor-bonded phases, 3-(N-carbazolyl)propylsilyl (CZP), 2-(1-pyrenyl)ethylsilyl (PYE), and 5-coronenylpentylsilyl (COP), were prepared from silica particles and their selectivities were examined in both polar and non-polar solvents for specific isomers of polychlorodibenzo-p-dioxins (PCDDs), hexachloronaphthalenes (HxCNs) and planar and non-planar polychlorobiphenyl (PCB) congeners. Although no single stationary phase was able to separate all the isomer pairs that are coproduced during the synthesis of the PCDDs and HxCNs, pairs can be separated by selecting a suitable stationary phase and solvent. The separation of mixtures of PCDD isomers were found to be most successful with PYE and NPO phases, which yielded the opposite elution orders for each isomer pair that is produced as a mixture. Similar results were obtained for the HxCN isomers that were separated on PYE and CZP phases. The COP phase provided easier separation of non-ortho-substituted and mono-ortho-substituted PCBs from the other PCBs based on the planarity than PYE phase.

Measurement of bisphenol A levels in human urine.

We report a new approach for assessing human exposure to bisphenol A (BPA) by measuring BPA in urine after enzymatic deglucuronidation. This method involves addition of (13)C(12)-labeled BPA, enzymatic deconjugation, solid-phase extraction, and derivatization with pentafluorobenzyl bromide. The product of the derivatization is separated by gas chromatography followed by mass spectrometric detection using negative chemical ionization and selected ion monitoring. Using this analysis method, urine samples fortified with both a constant level of labeled BPA and a range of unlabeled BPA levels (0.27-10.6 ng/ml) demonstrated constant percentage recovery. In addition, a range of urine sample volumes (0.25-10.0 ml) with constant amounts of added internal standard produced a linear response (r(2)=0.99). The method limit of detection was 0.12 ng/ml. This method was validated by duplicate analyses using gas chromatography coupled to a high-resolution mass spectrometer.

Angiosarcoma of serous membranes.

Three angiosarcomas of serous membrane are described. One originated in peritoneum, one in pleura, and one in pericardium. The tumor arising in peritoneum was a cystic lymphangiosarcoma and may have been caused by previous therapeutic irradiation for carcinoma of the endometrium. This tumor invaded the peritoneal and right pleural cavities extensively and thus resembled diffuse mesothelioma in its behavior. The tumors arising in pleura and pericardium were hemangiosarcomas.

Clear-cell epithelial neoplasms of the large intestine.

We report four cases of primary clear-cell adenoma and adenocarcinoma of the large intestine. The neoplasms grossly resembled ordinary colonic adenomas and adenocarcinomas but microscopically were composed of uniform cells with optically clear cytoplasm. Mucin stains were negative, and the clear nature of the cytoplasm was due to glycogen accumulation. Areas of transition between normal colonic epithelial constituents and the clear-cell lesion were observed. Three of the four cases stained strongly positively for carcinoembryonic antigen. These lesions are apt to give rise to considerable diagnostic confusion and, in particular, resemble metastatic renal cell carcinoma. The usual strong positive carcinoembryonic antigen reaction is helpful in establishing this diagnosis.

Retrospective detection of exposure to sulfur mustard: improvements on an assay for liquid chromatography-tandem mass spectrometry analysis of albumin-sulfur mustard adducts.

We here report on the further development of the method comprising the pronase digestion of albumin alkylated by sulfur mustard and the subsequent mass spectrometric analysis of an adducted tripeptide. This includes significant improvements in both the albumin isolation procedure and the automation of the microliquid chromatography-electrospray-tandem mass spectrometric analysis. We also report on the results of a small reference range study, in which we have established that there are no detectable interferences in sera from unexposed individuals.

Strongyloides stercoralis.

Strongyloides stercoralis, a nematode not well known to many Canadian physicians, infects 35% of some tropical populations. Larvae can be isolated from the stools in 25% of cases and from duodenal aspirates in 95%. Treatment is with thiabendazole given twice daily in a dose of 25 mg/kg up to a maximum of 1.5 g/d. Frenquently an individual with a previously asymptomatic infection presents with hyperinfection and death rapidly ensues, but usually classical symptoms are present. Such a case is described. Immunosuppression is frequently associated with the hyperinfective state.

The clinical recognition of cystic carcinoma of the breast.

Cystic malignant growths of the breast are uncommon, being only 1 per cent of all carcinomas of the breast. They can be easily diagnosed clinically by noting an unusual patient age, the nature of the fluid aspirated (bloody or peculiar) and recurrence or persistence of the "cyst." The results of cytologic examination of the aspirate has not been helpful in the diagnosis of these lesions.

Mode locking of a diode-laser-pumped Nd:glass laser by frequency modulation.

We report frequency-modulation mode locking of a diode-laser-pumped Nd:glass laser. We have obtained pulses of 9-psec duration using a lithium niobate phase modulator operating at a repetition rate of 235 MHz. The average output power is 14 mW, for pumping with a 500-mW laser-diode array, and the pulses are approximately 1.4 times transform limited.

Accurate optical frequency-interval measurement by use of nonresonant frequency comb generation.

A novel technique for measuring the separation of widely spaced optical frequencies is demonstrated. It relies on frequency comb generation by use of a laser that incorporates a frequency-shifting element. A Nd:YLF laser is used to produce a frequency comb that has a bandwidth of 140 GHz and that contains in excess of 875 discrete frequencies, accurately spaced by 160 MHz. The longitudinal mode spacing of a dual-frequency laser was measured to an accuracy of +/-5 kHz in 3,733,440.0 kHz by use of the technique described here.

Cystadenoma and cystadenocarcinoma of the pancreas.

Cystic neoplasms of the pancreas are uncommon. The authors present one case each of a cystic carcinoma (possibly acinar, which is a rare variant of pancreatic carcinoma), cystadenocarcinoma arising in a mucinous cystadenoma and cystadenoma. These cases illustrate important features of the natural history and management of these lesions. The macrocystic cystadenoma is generally regarded as premalignant and merits aggressive treatment, while the microcystic type is considered benign. If the cystadenoma is removed completely, there should be no recurrence. The cystadenocarcinoma differs from duct carcinoma; usually, the tumour can be removed, and when this is possible the prognosis is excellent. Both the cystadenoma and the cystadenocarcinoma can be mistaken for a pancreatic pseudocyst. The distinction is important.

Quantification of polycyclic aromatic hydrocarbons and polychlorinated dibenzo-p-dioxins in human serum by combined micelle-mediated extraction (cloud-point extraction) and HPLC.

Quantification of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated dibenzo-p-dioxins (PCDDs) usually requires preconcentration and cleanup prior to analysis. These procedures often involve using large amounts of toxic organic solvents. The sample preparation from serum is even more complex because of the coextraction of lipids and other nonpolar serum components. We describe the unprecedented use of cloud-point extraction to preconcentrate, extract, and clean up PAHs and PCDDs from human serum using the nonionic surfactant Triton X-100. The samples were analyzed by high-performance liquid chromatography with ultraviolet detection. The phase separation was induced by the addition of salt to the micellar serum solutions. The surfactant-rich phase was treated with acetonitrile and water to precipitate and remove some of the unwanted substances in the serum sample extract without significantly affecting the recoveries of the analytes. The favorable characteristics of cloud-point extraction discussed here strengthen its potential use as an alternative to other techniques of separation.

FM mode-locked, laser-diode-pumped La(1-x)Nd(x)MgAl(11)O(19) laser.

We report the operation of a laser diode pumped La(1-x)Nd(x)MgAl(11)O(19) laser mode locked by an electro-optic phase modulator. The repetition rate of the laser was 230 MHz, and the average output power was 50 mW, when pumped by a 500-mW broad-stripe laser diode. Transform-limited pulses of 14 ps duration were obtained. We have also demonstrated the FM operation of this laser, with bandwidths of up to 440 GHz being obtained.

Xanthurenic acid induces gametogenesis in Plasmodium, the malaria parasite.

A small, heat stable chromophore extracted from mosquitoes has recently been implicated as the signal that induces mating of Plasmodium, the malaria parasite. We have used high resolution electrospray mass spectrometry to determine that this gamete activation factor (GAF) has a m/z = 205.0450, suggesting a molecular species composition of C10H7NO4. Xanthurenic acid (XA), a product of tryptophan catabolism, was determined to have an elemental composition, ultraviolet absorbance maxima, and mass spectrum consistent with those characteristics of GAF. XA activated gametogenesis of Plasmodium gallinaceum and P. falciparum in vitro at concentrations lower than 0.5 microM in saline buffered to pH 7.4. A structural analog of XA, kynurenic acid (C10H6NO3), also activated gametogenesis but only at higher concentrations and with less effect. We propose that XA is GAF. This is the first evidence that XA has induction activity.

5-Alkylresorcinols from Hakea amplexicaulis that cleave DNA.

A dichloromethane extract of Hakea amplexicaulis was found to cause strand scission of phi X174 replicative form DNA in the presence of Cu(II). Bioassay-guided fractionation of this extract afforded five compounds capable of mediating DNA relaxation. Structure determination of the active principles indicated that they were 5-tridecylresorcinol (1), 5-pentadec-cis-8-enylresorcinol (2), 5-heptadeca-8,11-dienylresorcinol (3), 5-pentadecylresorcinol (4), and 5-heptadec-cis-8-enylresorcinol (5). As noted previously for compounds in this structural series, DNA cleavage was enhanced significantly by incubation under (alkaline) conditions known to promote oxygenation of the parent compounds on the aromatic nucleus.