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Competing Interests: The authors report no conflicts of interest.

Background: Angiogram negative sub-arachnoid haemorrhage (SAH) is generally considered to have a more benign course than SAH of known cause. There is also variability from centre to centre as to what proportion of angiogram negative SAH patients undergo repeat Digital Subtraction Angiography (DSA). We performed a retrospective study looking at the last four years' of SAH patients at our institution in order to ascertain the clinical course, the nature and results of repeat imaging., Methods: Retrospective analysis of clinical records and imaging of all patients presenting to our institution with non-traumatic SAH between April 2008 and February 2012 was performed. Results were analysed for presenting grades, blood distribution, complications, outcomes, repeat imaging modalities and findings., Results: 459 patients with proven non-traumatic SAH of which 50 (11%) had no vascular cause identified on their initial angiogram were identified. The blood distribution was perimesencephalic in 17, non-perimesencephalic in 23, and 10 patients were computed tomography (CT) Negative with a positive lumbar puncture. Eight (16%) patients were complicated by hydrocephalus and 2 (4%) were complicated by vasospasm. Eight patients (16%) underwent repeat cranial DSA with a high suspicion in a multi-disciplinary team setting. None of the repeat angiograms showed an underlying aetiology for the SAH. 76% of patients had a Glasgow Outcome Score of 5 at 6 months. There were no rebleeds., Conclusions: While generally more benign, angiogram negative subarachnoid haemorrhage can have a complicated clinical course. In our experience repeat DSA should be reserved for cases in which there is significant suspicion of occult vascular lesion. However, evidence-based guidelines are needed to aid the development of management protocols for angiogram-negative SAH and ensuring optimal patient outcomes., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The convenient preparation of chiral tetrahydrothiophenes (THTs) in high enantiopurity via phosphorothioic acids and related compounds is reported. We consider these to be safer alternatives to the use of H(2)S which is a highly toxic gas. Each of the THTs is derived from a common intermediate, thereby greatly enhancing the flexibility of the synthesis. The key transformation is a base-promoted, intramolecular, carbon-sulfur bond-forming event. These reactions are highly stereospecific as they operate through a double S(N)2 displacement mechanism. The methodology is amenable to a broad array of functional groups and heterocycles. The tetrahydrothiophene motif is important because it is present in a number of bioactive natural products. They have also been utilized to promote various asymmetric transformations including hydrogenation, epoxidation, cyclopropanation, and aziridination reactions.

An hemolysis-in-gel test (HIGT) for bovine antibody against Brucella abortus was developed and evaluated. Sera to be tested were placed in wells in an agarose gel containing guinea pig complement and J-negative bovine erythrocytes coated with lipopolysaccharide prepared from B. abortus biotype 1. After incubation, zones of hemolysis were produced by positive sera. The activity of some positive sera was heat labile, but was restored to heated sera by addition of a crude preparation of the first component of bovine complement. The HIGT was compared with the complement fixation test (CFT), the buffered antigen plate test (BPAT), the standard tube agglutination test (STAT) and the standard plate agglutination test (SPAT), using sera from 1041 brucellosis-free cattle, from 51 cattle infected with B. abortus biotype 1 or biotype 4, and from six heifers vaccinated with strain 19. Three of 1041 sera (0.29%) from brucellosis-free cattle were HIGT-positive, ten (0.96%) were BPAT-positive, and none were positive in the CFT, STAT, or SPAT. The HIGT was more sensitive, and detected infection earlier than the other tests in the case of B. abortus biotype 1 infection, but was less sensitive for biotype 4 infection. In vaccinated heifers, HIGT reactions appeared later than reactions to the other tests, and persisted as long as 565 days. Further studies are needed to standardize the HIGT test conditions and to improve its sensitivity for B. abortus biotype 4 infections. Attempts to determine the effects of LPS antigen prepared from different biotypes of B. abortus are in progress.

Five serological assays: the buffered plate antigen test, the standard tube agglutination test, the complement fixation test, the hemolysis-in-gel test and the indirect enzyme immunoassay were diagnostically evaluated. Test data consisted of results from 1208 cattle in brucellosis-free herds, 1578 cattle in reactor herds of unknown infection status and 174 cattle from which Brucella abortus had been cultured. The complement fixation test had the highest specificity in both nonvaccinated and vaccinated cattle. The indirect enzyme immunoassay, if interpreted at a high threshold, also exhibited a high specificity in both groups of cattle. The hemolysis-in-gel test had a very high specificity when used in nonvaccinated cattle but quite a low specificity among vaccinates. With the exception of the complement fixation test, all tests had high sensitivities if interpreted at the minimum threshold. However, the sensitivities of the standard tube agglutination test and indirect enzyme immunoassay, when interpreted at high thresholds were comparable to that of the complement fixation test. A kappa statistic was used to measure the agreement between the various tests. In general the kappa statistics were quite low, suggesting that the various tests may detect different antibody isotypes. There was however, good agreement between the buffered plate antigen test and standard tube agglutination test (the two agglutination tests evaluated) and between the complement fixation test and the indirect enzyme immunoassay when interpreted at a high threshold. With the exception of the buffered plate antigen test, all tests were evaluated as confirmatory tests by estimating their specificity and sensitivity on screening-test positive samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Six agglutination and two complement fixation tests were compared with respect to specificity, sensitivity and relative sensitivity for the serodiagnosis of bovine brucellosis. Based on 1051 sera from brucellosis free herds, the specificity of the tests was 98.9% for the buffered plate antigen test (BPAT), 99.2% and 99.3% for the standard tube and plate agglutination tests (STAT and SPAT), respectively, and 99.8% for the 2-mercaptoethanol test (2MET). On this small sample, the rose bengal plate test (RBPT), card test (CARD) and the complement fixation test (CFT) correctly classed all sera as negative. On a sample of 167 culture positive cattle, the sensitivities of the tests were CFT: 79.0%, BPAT: 75.4, RBPT: 74.9%, CARD: 74.3%, SPAT: 73.1%, STAT: 68.9%, and 2MET: 59.9%. All tests combined detected only 82% of these infected cattle. Analysis of the relative sensitivity of the six agglutination tests gave the following ranking: BPAT greater than RBPT greater than CARD greater than SPAT greater than STAT. The 2MET ranked between the BPAT and RBPT or between the RBPT and CARD depending on the analysis used. The use of the BPAT as a screening test is recommended provided that a test of high specificity and sensitivity such as the CFT is used to confirm screening test reactions.