The three phases of vasospasm.

We propose the theory that prolonged cerebral vasospasm involves three phases: (1) the initial muscular contraction of the arterial wall; (2) a secondary injury to the artery that consists of endothelial desquamation with adherence of platelets to te denuded internal elastic lamina and mural thrombus formation; and (3) the repair process, which is the proliferative endarteropathy that has been observed in autopsy specimens. Cerebral ischemia can be the end product of any of these three conditions. We have postulated a possible subcycle in the overall scheme by which adherence of platelets to the denuded internal elastic lamina of the artery provide a continuously replenishing supply of spasmogenic chemical factors to the mural receptors and stimulate prolonged contraction of the muscular layer. We propose that this cycle may be interrupted by the administration of heparin. To test this hypothesis, the records of 112 consecutive patients who received systemic heparin in conjunction with carotid ligation were compared with the results of carotid ligation reported in the Cooperative Study, in which heparin was not used. The incidence of ischemic complications in the group of patients receiving heparin was 6%, as compared to 23% in control group, with a concomitant reduction in mortality from 16% to 10%. The incidence of recurrent subarachnoid hemorrhage was slightly less in the patients receiving heparin than in patients in the Cooperative Study. We conclude that the data provide support for our hypothesis of the mechanism of prolonged cerebral vasospasm and cerebral ischemia associated with subarachnoid hemorrhage, and that systemic heparin may be used with relative safety in patients in whom the aneurysm if protected by partial carotid ligation.

In-Vitro and In-Vivo Effects of Aldicarb on Survival and Development of Heterodera schachtii.

Aqueous solutions of 5-500 mug/ml aldicarb inhibited hatching of Heterodera schachtii. Addition of hatching agents, zinc chloride, or sugarbeet root diffusate, to the aldicarb solutions did not decrease the inhibition of hatching. When cysts were removed from the aldicarb solufions and then treated for 4 wk in sugarbeet root diffusate, larvae hatched and emerged. Treatments of newly hatched larvae of H. schachtii with 5-100 mug/ml aldicarb depressed later development of larvae on sugarbeet (Beta vulgaris). Similar treatments with aldicarb sulfoxide had less effect on larval development, and aldicarb sulfone had no effect. Numbers of treated larvae that survived and developed were inversely proportional to concentration (0.1-5.0 mug/ml) and duration (0-14 days) of aldicarb treatments. Development of H. schachtii on sugarbeet grown in aldicarb-treated soil was inversely proportional to the concentration of aldicarb in the tested range of 0.75 - 3.0 mug aldicarb/g of soil. Transfer of nematode-infected plants to soil with aldicarb retarded nematode development, whereas transfer of plants first grownin treated soil to nematode-infested soil only slightly suppressed nematode development. Development of H. schachtii was inhibited in slices of storage roots of table beet (B. vulgaris), sugarbeet and turnip, (Brassica rapa), that had grown in soil treated with aldicarb.

Efficacy of 1,2-Dibromo-3-chloropropane for Control of Meloidogyne javanica as Influenced by Concentration, Exposure Time and Rate of Degradation.

Laboratory experiments were conducted by applying 1,2-dibromo-3-chloropropane (DBCP) to sealed vials of soil infested with Meloidogyne javanica. A minimum initial concentration of 0.25 mug of DBCP/g of oven-dry soil killed all nematodes within 35 days. A concentration of 1.0 mug/g killed all nematodes within 28 days. The rate of degradation of this chemical was determined by treatment of steamed and nonsteamed dry soil in open and sealed vials. Extraction of tile chemical, followed by quantification by gas chromatography, showed approximately 100% of the amount applied recovered after 14 days in sealed vials without soil. With soil present, approximately 10% of the amount of chemical applied was recovered.

Most-probable-number rapid viability PCR method to detect viable spores of Bacillus anthracis in swab samples.

A comparison of Most-Probable-Number Rapid Viability (MPN RV) PCR and traditional culture methods for the quantification of Bacillus anthracis Sterne spores in macrofoam swabs from a multi-center validation study was performed. The purpose of the study was to compare environmental swab processing methods for recovery, detection, and quantification of viable B. anthracis spores from surfaces. Results show that spore numbers provided by the MPN RV-PCR method were typically within 1-log of the values from a plate count method for all three levels of spores tested (3.1x10(4), 400, and 40 spores sampled from surfaces with swabs) even in the presence of debris. The MPN method tended to overestimate the expected result, especially at lower spore levels. Blind negative samples were correctly identified using both methods showing a lack of cross contamination. In addition to detecting low levels of spores in environmental conditions, the MPN RV-PCR method is specific, and compatible with automated high-throughput sample processing and analysis protocols, enhancing its utility for characterization and clearance following a biothreat agent release.

Evaluation of a macrofoam swab protocol for the recovery of Bacillus anthracis spores from a steel surface.

A protocol to recover Bacillus anthracis spores from a steel surface using macrofoam swabs was evaluated for its accuracy, precision, reproducibility, and limit of detection. Macrofoam swabs recovered 31.7 to 49.1% of spores from 10-cm2 steel surfaces with a < or =32.7% coefficient of variation in sampling precision and reproducibility for inocula of > or =38 spores.