Synthesis of halogenated analogs of 5-(4-chlorophenyl)-2,3-dihydro-5-hydroxy-5H-imidazo[2,1-a]-isoindole or mazindol for exploration of the dopamine transporter

In order to study the presynaptic dopamine transporter in the human brain by single photon emission tomography (SPET) or positron emission tomography (PET) we have developed new halogenated mazindol derivatives using a pathway involving a reaction between a dilithio derivative of 2-phenyl-2-imidazoline and appropriate methyl or ethyl halogenobenzoates. After HPLC purification and chemical characterization, the affinity for the dopamine transporter was studied in vitro with [³H]-GBR 12935 and compared to mazindol and nomifensine. Affinity potencies were determined as follow:- mazindol > brominated derivatives > iodinated derivatives > nomifensine > fluorinated derivatives. The properties were related to the structure of these compounds and showed the importance of the nature of the substituent on the primary phenyl ring of mazindol for affinity to the dopamine transporter.     

The costs of early hearing screening in England and Wales

A survey was carried out in 10 centres in England and Wales to determine the costs of hearing screening in the first year of life. The screens that were studied were targeted neonatal, universal neonatal, and the health visitor distraction test (HVDT) or alternative surveillance. Valid data were available from five centres for targeted neonatal screening (TNS), three for universal neonatal screening (UNS), and nine for the HVDT, although only five of the HVDT screens had valid data for follow up costs. The neonatal costs were consistent across the centres surveyed, whereas those for the HVDT screen varied considerably. The mean service costs for TNS, UNS, and the HVDT at 1994 prices were 5052 Pounds, 13,881 Pounds, and 24,519 Pounds for a standardised district of 1000 live births. Three conclusions seem justified. Firstly, UNS need not be prohibitively expensive as it costs considerably less than HVDT screening. Secondly, TNS appears to be a relatively inexpensive way of improving the age of identification of a proportion of the congenitally hearing impaired. Thirdly, given the published yields for UNS and the HVDT, the results indicate that UNS offers the most cost effective overall approach with alternative systems in place to identify late onset permanent hearing losses.     

Physical properties of biaxially oriented poly(ethylene terephthalate) film as affected by dimethyl sulfoxide

The effects of a strongly interacting solvent, i.e., dimethyl sulfoxide (DMSO), on several physical properties of biaxially oriented and annealed (210°C) poly(ethylene terephthalate) (PETP) films were investigated. Physical properties which reflect changes in bulk morphology such as density, thermal behavior, tensile properties, and deformation dilatometric measurements were found to be dependent upon the temperatures of solvent treatment in the range between 60 and 160°C. The densities of PETP films were lowered to a minimum at solvent temperatures of 100 and 120°C with a slight recovery at higher temperatures. A similar dependence on solvent temperature was also observed on the heat of fusion and yield stress data. The pressure decrease in dilatometric measurements during step-wise deformation of untreated PETP were explained by gas adsorption. Gas adsorption may be due to decreased molecular order in PETP during deformation. Higher gas adsorption on PETP treated with DMSO at temperatures at and above 80°C further substantiated that internal spaces were induced by DMSO at elevated temperatures. These solvent-induced spaces were deformed under stress, thus creating surfaces and spaces for additional gas adsorption. The results show that the energy from a strongly interacting chemical, such as DMSO, can induce microstructural changes in PETP below the previous processing (drawing and annealing) temperatures.     

Long-term central venous access with a peripherally placed subcutaneous infusion port: initial results

A new subcutaneous infusion port and catheter system for long-term central venous access, designed to be implanted in the interventional radiology suite, was evaluated. In 35 patients, a 5-F polyurethane catheter was placed in the superior vena cava via the axillary or brachial venous approach under fluoroscopic guidance. A 2.5 X 2.5-cm2 subcutaneous pocket was dissected for the port. The port was then connected to the catheter, and the incision was closed. Ports have been implanted for a total of 5,290 patient days (5-307 days for an individual patient). Blood transfusion, bolus drug administrations, and 5-day outpatient chemotherapy infusions were successful in all attempts. Blood sampling was successful in 98.9% of attempts. No infectious or thrombotic complications were encountered. Acceptance of this device by patients and nursing staff has been excellent. The initial results indicate that this peripherally placed port is a viable alternative for patients requiring long-term central venous access.