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SignificanceThe intravascular processing of triglyceride-rich lipoproteins by the lipoprotein lipase (LPL)–GPIHBP1 complex is crucial for clearing triglycerides from the bloodstream and for the delivery of lipid nutrients to vital tissues. A deficiency of either LPL or GPIHBP1 impairs triglyceride processing, resulting in severe hypertriglyceridemia (chylomicronemia). Despite intensive investigation by biochemists worldwide, the structures for LPL and GPIHBP1 have remained elusive. Inspired by the recent discovery that GPIHBP1 stabilizes LPL structure and activity, we crystallized the LPL–GPIHBP1 complex and solved its structure. The structure provides insights into the ability of GPIHBP1 to preserve LPL structure and activity and also reveals how inherited defects in these proteins impair triglyceride hydrolysis and cause chylomicronemia.

Acinetobacter isolates from eight subjects with community-acquired Acinetobacter pneumonia (CAAP), a major cause of fatal community-acquired pneumonia in tropical Australia, were phenotypically and genotypically confirmed by pulsed-field gel electrophoresis analysis to be broadly diverse Acinetobacter baumannii strains. Wet-season throat carriage of A. baumannii was found in 10% of community residents with excess levels of alcohol consumption, the major at-risk group for CAAP.

PCR technology offers alternatives to conventional diagnosis ofCryptosporidium for both clinical and environmental samples. We compared microscopic examination by a conventional acid-fast staining procedure with a recently developed PCR test that can not only detect Cryptosporidium but is also able to differentiate between what appear to be host-adapted genotypes of the parasite. Examinations were performed on 511 stool specimens referred for screening on the basis of diarrhea. PCR detected a total of 36 positives out of the 511 samples, while routine microscopy detected 29 positives. Additional positives detected by PCR were eventually confirmed to be positive by microscopy. A total of five samples that were positive by routine microscopy at Western Diagnostic Pathology but negative by PCR and by microscopy in our laboratory were treated as false positives. Microscopy therefore exhibited 83.7% sensitivity and 98.9% specificity compared to PCR. PCR was more sensitive and easier to interpret but required more hands-on time to perform and was more expensive than microscopy. PCR, however, was very adaptable to batch analysis, reducing the costs considerably. Bulk buying of reagents and modifications to the procedure would decrease the cost of the PCR test even more. An important advantage of the PCR test, its ability to directly differentiate between different Cryptosporidiumgenotypes, will assist in determining the source of cryptosporidial outbreaks. Sensitivity, specificity, ability to genotype, ease of use, and adaptability to batch testing make PCR a useful tool for future diagnosis and studies on the molecular epidemiology ofCryptosporidium infections.

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