Intermodality, retrospective image registration in the thorax

The purpose of this study was to develop an accurate, retrospectively applicable procedure for registering thoracic studies from different modalities in a short amount of time and with minimal operator intervention. METHODS: CT and PET studies were acquired from six patients. The pleural surfaces in both image sets were determined by segmenting based on 50% of the maximum soft-tissue value in the study. These surfaces were converted into three-dimensional volumes and used to register the CT and PET studies in three dimensions using a sum of least squares fitting approach. The registered PET study was then displayed in a hot metal scale overlayed on top of the gray scale CT study. The accuracy of the fit was evaluated through a phantom study and preliminary clinical evaluation. RESULTS: A phantom study was performed to determine the limits of this technique. The accuracy was determined to be less than 2.3 mm in the x and y direction and 3 mm in the z direction. Preliminary clinical evaluation was also performed with encouraging results. CONCLUSION: This technique accurately registers PET and CT images of the thorax, retrospectively, without the need for external fiducial markers or other a priori action.     

Experience with the antibiotic resistance analysis and DNA fingerprinting in tracking faecal pollution at two lake beaches.

Posting or closing of swimming beaches because of faecal contamination is a widespread problem reported in many locations. In a risk-based approach to this problem, the risk to swimmers' health is assessed by field monitoring of indicator bacteria and the associated risks are managed by source controls and other remedial measures. In risk assessment, great advances have been made in recent years with the introduction of microbial source tracking (MST) techniques. Two such techniques, antibiotic resistance analysis and DNA fingerprinting, were applied in a study of causes of faecal contamination at two lake beaches in Toronto, Ontario. Both methods identified bird faeces as the dominant sources of E. coli. Coping with this type of pollution presents a major environmental challenge.     

Activating and inactivating mutations in LH receptors

In rats, galanin modulates luteinizing hormone (LH) secretion, and gonadotropin-releasing hormone (GnRH) neurons provide a possible source of this galanin. To understand galanin's physiological role in GnRH neurons, we used double-label in situ hybridization and computerized image analysis to examine the regulation of galanin message in GnRH neurons. We found that galanin gene expression in GnRH neurons is regulated by sex steroids, induced coincident with the LH surge, and persists well after the completion of the LH surge, and that the induction of galanin message in GnRH neurons coincident with the LH surge is sexually differentiated neonatally. We postulate that the rise in galanin gene expression in GnRH neurons at the time of the LH surge serves to replenish galanin released with GnRH that is needed for the production of the LH surge, or that galanin is involved in physiological events that occur subsequent to the LH surge.     

Enantioselective synthesis and pharmacology of 11-hydroxy-(1'S,2'R)-dimethylheptyl-delta 8-THC

An enantioselective synthesis of the (1'S,2'R)-dimethylheptyl cannabinoid side chain has been developed and employed in the synthesis of 11-hydroxy-(1'S,2'R)-dimethylheptyl-delta 8-THC (3). Pharmacology, in vivo and in vitro, indicate (3) to be one of the most potent traditional cannabinoids known.     

A precision machine for mounting tissue for Mohs micrographic surgery

BACKGROUND: Mounting specimens onto chucks, so the cryostat knife follows the exact path of the surgeon's knife, poses difficulties even for experienced histotechnologists. Oftentimes, the frozen planar surface of the tissue falls at an angle that requires gimballing the chuck holder to compensate. OBJECTIVE: To demonstrate the use of a precision tissue mounting machine and associated fast freezing chucks. METHODS: Specimens of pickled pig skin were marked with blue dye on the cut surface. The pieces were mounted onto chucks with the blue surface exposed, and then sectioned in a cryostat. RESULTS: A complete section with all edges was obtained after eight turns of the cryostat handwheel, at 12 microns per turn. CONCLUSIONS: A precision machine used in conjunction with a properly adjusted chuck holder can yield results unobtainable by other methods.     

Influence of short-term dietary measures on dioxin concentrations in human milk

Breast-feeding may expose infants to high levels of toxic chlorinated dioxins. To diminish intake of these lipophilic compounds by the baby, two diets were tested for their ability to reduce concentrations of dioxins in human milk. The diets were a low-fat/high- carbohydrate/low-dioxin diet. (about 20% of energy intake derived from fat) and a high fat /low-carbohydrate/low-dioxin diet. These diets were tested in 16 and 18 breast-feeding women, respectively. The test diets were followed for 5 consecutive days in the fourth week after delivery. Milk was sampled before and at the end of the dietary regimen, and dioxin concentrations and fatty acid concentrations were determined. Despite significant influences of these diets on the fatty acid profiles, no significant influence on the dioxin concentrations in breast milk could be found. We conclude that short-term dietary measures will not reduce dioxin concentration in human milk.