Bone properties surrounding hydroxyapatite-coated custom osseous integrated dental implants.

Calcium phosphate (hydroxyapatite or HA) coatings have been applied to Custom Osseous Integrated Implants (COIIs) to improve the quality of the bone-implant integration, yet little is known concerning the biomechanical properties of bone surrounding the HA-coated implants in humans over the long term. The purpose of this study was to characterize the mechanical and histomorphometric properties of the bone along the implant interface. Specimens were prepared from three similar mandibular implants that were functional in three female patients for about 11 years. Histomorphometric analyses showed bone-implant contact averaging 75% for all specimens. Area coverage of residual HA-coating ranged from 52 to 70%. When compared with previous studies, these results show a relatively high percentage of residual HA after a decade in vivo. Nanoindentation showed similar average values of hardness and modulus (p = 0.53 and p = 0.56, respectively) comparing bone adjacent to residual HA-coating and regions where the coating was absent. The elastic modulus was significantly lower for bone near the bone-implant interface (<200 µm) as compared with bone distant (>1000 µm) from the interface (p = 0.05), thereby reflecting different properties of the bone near these interfaces. Backscattered electron imaging showed darker gray levels which indicated decreased mineral content in bone adjacent to the implant, consistent with the nanoindentation results.

Comparison of strontium-89 solution sources in UK hospitals, 2003.

Concerns have been raised within the nuclear medicine field about the accuracy of measurements of 89Sr. The 85Sr impurity present in the 89Sr solution has a significant effect on the response of radionuclide calibrators used in hospitals. A comparison was conducted between the National Physical Laboratory (NPL) and the UK hospital physics community. Only 58% of the results were within 5% of the NPL value. Work at NPL has resulted in correction factors for the NPL secondary standard radionuclide calibrator and for Capintec calibrators, which will produce a significant improvement in performance.

Standardisation of 11C.

The increasing use of positron emission tomography for medical imaging and the availability of short-lived positron emitters has raised concerns about the accuracy of calibration of secondary standard measurement systems and the viability of using a single long-lived positron emitter as a reference calibration source for all positron emitters. Potential problems arise because the 511 keV quanta arising from positron annihilation are not generally produced at the same point as the original disintegration. In addition, the secondary standard may also be responsive to the associated bremsstrahlung radiation. The magnitude of both effects depends on the positron end-point energy. In order to resolve these problems, it is necessary to produce absolute standards of these positron-emitting radionuclides and the work presented here details the results of such work with 11C.

Challenges of developing a cervical screening information system: the Ontario pilot project.

OBJECTIVE: To create a cervical screening information and reporting system in 2 geographic areas of Ontario. DESIGN: A pilot project involving access to, and linkage of, cervical screening-related cytology, colposcopy and histopathology records for women in the study areas, followed by development and production of woman-specific and aggregate reports. SETTING: Hospital cytology and pathology departments, colposcopy clinics, private cytology laboratories, and the provincial cancer agency (Cancer Care Ontario, formerly the Ontario Cancer Treatment and Research Foundation). MAIN OUTCOME MEASURES: Access to required records; data quality (i.e., standardization, completeness, accuracy); quality of record linkage; utility of reports to evaluators, data sources and physicians. RESULTS: The pilot project was not completed because of a number of major challenges, including multiple data sources requiring separate investigation and negotiations for access; variations in reporting terminology and coding; incompatibility or lack of computer systems; incompleteness of identifiers for record linkage; variation in legislation permitting data access and sharing and in its interpretation; and major financial, resource and time requirements. CONCLUSIONS: Although sufficient will and resources can overcome technical obstacles, changes in legislation will be required to overcome other challenges. Strong links with all sectors involved in cervical screening and attention to changes in the health care system are essential.

The use of benzodiazepine hypnotics in the elderly.

An epidemiologic study was conducted to observe patient-reported use and effects of triazolam, flurazepam, and oxazepam taken at bedtime among 2260 outpatients age 65 years or older in Canada. The study used pharmacy-based enrollment, with participant follow-up through a 3-day diary and a telephone interview. The study also evaluated how the three benzodiazepine hypnotics were prescribed. Prescription information showed that 66% of the flurazepam prescriptions were for the highest strength, compared to 39% and 35% for triazolam and oxazepam, respectively. As patient age increased, the highest strength of each agent was prescribed less frequently. For all drugs, 53% of prescriptions were written for use as necessary (prn), and the proportion who received such prescriptions increased with age. Patient reports, however, revealed that 57% were using a hypnotic every day, and this regular use increased with advancing age. Regular daily use was more common among those who used triazolam and oxazepam (62%) than those who took flurazepam (42%).

Is post-marketing drug surveillance possible in the family practice setting? A collaborative study.

Post-marketing surveillance is a mechanism to identify and quantify harmful, as well as beneficial, effects of drugs used under conditions different from those in which they were tested. The College of Family Physicians of Canada collaborated with the authors in a pilot, office-based, post-marketing, surveillance study. Target medications were selected from all prescriptions, written or authorized by participating physicians. The participants collected the prescriptions by using duplicate prescription pads. Follow-up data was collected from the patients by means of a self-administered questionnaire and from the physicians by means of a medical-chart review. This method of research allows the identification of a cohort of drug users in a systematic, non-biased fashion.