Discordant repeat size and phenotype in Kennedy syndrome

Previous reports in the literature have described correlation of increasing repeat length with severity of the phenotype, in Kennedy syndrome. We describe male siblings with different repeat lengths, with lack of expression of the phenotype in the sibling with the longer repeat length. The phenotype was identical to motor neurone disease. There is variability of expression in Kennedy syndrome and repeat length even in siblings cannot be taken as a conclusive indicator of severity. CAG repeat length cannot be used to predict the natural history of Kennedy disease. The diagnosis of Kennedy syndrome should be considered in male patients presenting with atypical motor neurone disease.     

Imaging spectrum in disseminated histoplasmosis: Case report and brief review

The clinical manifestations of chronic disseminated histoplasmosis are non-specific and resemble those of other chronic infections and malignancies. We report the radiographic, sonographic and contrast-enhanced CT appearances of histoplasmosis in an adult male with non-insulin dependent diabetes mellitus, who was HIV negative and presented with weight loss and pyrexia. Imaging studies simulated tuberculosis with mediastinal lymphadenopathy, bilateral fibrotic lung lesions, hepatomegaly and bilateral hypoattenuating adrenal enlargement, without clinical or laboratory evidence of hypoadrenalism. Computed tomography-guided fine-needle aspiration biopsy of adrenal glands revealed Histoplasma capsulatum. We report our experience to increase awareness of the imaging spectrum of disseminated histoplasmosis and its similarity to tuberculosis as, with increasing incidence of AIDS, the chances of these infections are likely to increase. Moreover, awareness of this entity is important because it is known that untreated disseminated histoplasmosis is fatal.     

Pharmacokinetics of oral vs. intravenous dexamethasone in patients hospitalized with community-acquired pneumonia

Aim

The use of corticosteroids as adjunctive therapy might be effective in patients with community-acquired pneumonia (CAP). Oral administration of dexamethasone is a practical and safer alternative to the intravenous route. Since patients hospitalized with pneumonia might have delayed gastric emptying, this study explored systemic exposure in terms of area under the concentration–time curve (AUC) of oral dexamethasone in patients hospitalized with CAP.

Methods

In this randomized, open label study, 30 patients admitted with CAP were randomized to receive either 4 mg intravenous or 6 mg oral dexamethasone for 4 consecutive days. Serial blood samples were obtained before and after drug administration.

Results

Median AUC to infinity was 626 μg l⁻¹ h (IQR 401–1161) for the intravenous group and 774 μg l⁻¹ h (IQR 618–1146) for the oral group. The AUC ratio of 6 mg oral and 4 mg intravenous dexamethasone was 1.22 (95% confidence interval (CI) 0.81, 1.82)_, which represents a bioavailability of 81% (95% CI 54, 121) after correction for differences in dexamethasone dose.

Conclusions

Bioavailability of oral dexamethasone in patients hospitalized with pneumonia is sufficient. This makes oral dexamethasone an appropriate alternative for intravenous administration in these patients.     

Characterization of a streptomycin-sulfonamide resistance plasmid from Actinobacillus pleuropneumoniae.

An Actinobacillus pleuropneumoniae strain contained a plasmid (pHD8.1) conferring resistance to streptomycin and sulfonamide. Restriction endonuclease mapping and DNA-DNA hybridization showed that pHD8.1 is related to RSF1010 from Salmonella panama, which also confers resistance to streptomycin and sulfonamide, and to pHD148 from Haemophilus ducreyi, which confers resistance only to sulfonamide.     

Plasmid-mediated tetracycline resistance in Haemophilus ducreyi.

Clinical isolates of Haemophilus ducreyi were shown to be resistant to tetracycline. Resistance was associated in some strains with a 30-megadalton plasmid capable of transferring resistance in conjugative matings with other strains of H. ducreyi and other species of Haemophilus. Restriction endonuclease digestion patterns suggest a relationship between H. ducreyi plasmids and other tetracycline resistance plasmids in Haemophilus. The presence of plasmid-mediated resistance to the tetracyclines limits the use of these agents for the treatment of chancroid.     

Cost-Effective Algorithm for Detection and Identification of Vancomycin-Resistant Enterococci in Surveillance Cultures

 A study was undertaken to develop an easy-to-use and cost-effective algorithm for the detection and identification of vancomycin-resistant enterococci (VRE) in surveillance cultures, because the incidence of VRE outbreaks in institutions across Canada has made continuous surveillance a necessity. Enterococcus faecium and Enterococcus faecalis carry transferable resistance genes and hence are a problem for infection control. In laboratory surveillance, however, Enterococcus gallinarum and Enterococcus casseliflavus, which exhibit low-level nontransferable resistance, are also encountered and often create confusion in identification. Included in this study were a total of 218 strains of enterococci and other streptococci isolated from surveillance cultures. Conventional methods were used to determine their biochemical activities, and speciation was attempted in 121 strains using a rapid multiplex polymerase chain reaction (PCR) method that utilized primers for the vanA, B, C1, C2/C3 and ddl genes. The results indicated that by using only a few tests (Gram stain, pyrrolidonyl arylamidase activity, motility, xylose and methyl-α-D-glucopyranoside utilization), Enterococcus faecium/faecalis strains could be accurately differentiated from Enterococcus gallinarum/casseliflavus strains. For the 121 strains on which PCR was performed, there was a 100% correlation with the biochemical identification, with the added advantage that the presence of van genes could be determined at the same time. The cost of identification using minimal biochemical testing and PCR was less than that of identification using automated systems or a battery of conventional biochemical methods. The algorithm presented here may be used in the microbiology laboratory.     

Purification of Hageman factor (factor XII) on columns of popcorn- agarose

Purification of Hageman factor (HF, factor XII) from human plasma is a tedious procedure and the product is not always in the precursor form. Hojima has described a protein derived from corn kernels that inhibits the enzymatic properties of HF. This inhibitor binds to the precursor form of HF. Rapid purification of HF was achieved by using as the major purification step adsorption of this clotting factor to popcorn inhibitor bound to agarose. The product had a specific activity of 50.0 to 67.1 coagulant units of HF per milligram protein, and the yield was 33% to 40% of the HF content of the starting plasma. The purified protein displayed a single band upon unreduced or reduced sodium dodecyl sulfate polyacrylamide gel electrophoresis and less than 0.1% was in an activated form, as measured in coagulant assays. The technique described is more rapid and reliable than methods described earlier.