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Biomedical subjects

D MacKenzie

Publications and source records attributed to D MacKenzie.

At least 37 records · Page 2Linked to original sources
PubMed1998

Comparison of potency of inhaled beclomethasone and budesonide in New Zealand: retrospective study of computerised general practice records.

OBJECTIVE: To determine whether inhaled budesonide and beclomethasone are equipotent in the treatment of asthma in primary care. DESIGN: Retrospective study of computerised clinical records from 28 general practices in New Zealand. SUBJECTS: 5930 patients who received 16 725 prescriptions for inhaled budesonide or beclomethasone from 1 July 1994 to 30 June 1995. SETTING: General practices on the database of the Royal New Zealand College of General Practitioners Research Unit. Linked information from secondary care was available for a subset of the practices. MAIN OUTCOME MEASURE: Mean prescribed daily inhaled corticosteroid dose. RESULTS: The daily prescribed dose was higher for patients receiving inhaled budesonide (mean 979 microg) than beclomethasone (mean 635 microg), a difference of 344 microg (95% confidence interval 313 to 376 microg). This difference was consistent in all age bands and with different types of inhalation device. Evidence of systematic prescribing of higher doses of budesonide to patients with more severe asthma was not found. CONCLUSIONS: In primary care in New Zealand evidence suggests that budesonide is less potent than beclomethasone. Consideration of validated, established, and other possible markers of asthma severity did not support confounding by severity as a reason for the higher prescribed doses of budesonide. Pending further epidemiological evaluation, international asthma guidelines may need to be modified on the equivalence of inhaled corticosteroid doses. Furthermore, the comparative potency of newly developed inhaled steroids in clinical trials will need to be confirmed in appropriately designed epidemiological studies based in general practice.

Administration, Inhalation↗
PubMed1998

Polymicrobial coronal leakage of super EBA root-end fillings following two methods of root-end preparation.

The aim of this study was to compose in vitro coronal leakage of a super EBA root-end filling material after two root-end cavity preparation techniques. A mixed anaerobic microbial marker was used. Forty-five extracted human teeth with straight, single root canals were prepared chemo-mechanically to a size 40 master apical file. The teeth were divided into experimental groups (35 teeth) and control groups (10 teeth). Forty teeth (35 experimental teeth and five negative control teeth) were obturated by lateral condensation of cold gutta-percha with Tubliseal EWT sealer. The remaining five teeth were not obturated and served as positive controls. These teeth were stored for 6 months in artificial saliva. The apical 3-4 mm of each root was resected perpendicular to the long axis of the root and a root-end cavity prepared to a depth of 3 mm using either a size 008 rosehead burr or an ultrasonic retroprep tip. Freshly mixed EBA cement was placed into the root-end cavity. The entire root surface of each tooth, except the cutting surface of the apical end, was sealed with nail varnish. The coronal part of each root canal was sealed with the cut end of a tube and placed in a bottle containing sterile Brain Heart Infusion Broth (BHIB). A marker consisting of Anaerobic streptococci and Fusobacterium nucleatum in BHIB was placed in each coronal chamber at 7-day intervals and daily observations were made for bacterial growth in the apical chamber for 60 days. All positive control teeth exhibited bacterial leakage within 48 h, whilst the apical chamber of negative control teeth remained uncontaminated throughout the test period. Fifty-nine percent (n = 10) of the specimens prepared with a burr showed leakage after 90 days, whilst only 22% (n = 4) of the ultrasonically prepared group showed leakage after the same time. The group prepared with ultrasonic tips showed statistically significant less specimens with leakage (P < 0.05) than the group prepared with burrs.

Dental Leakage↗
PubMed1998

Smoking cessation, physicians, and medical office staff. Clinical tobacco intervention in Prince Edward Island.

OBJECTIVE: To assess attitudes and self-reported behaviours of physicians and medical office staff in Prince Edward Island concerning clinical tobacco intervention (CTI). DESIGN: Mail survey of PEI primary care physicians and their medical office staff. Most surveys were not mailed back but picked up in person by research staff. SETTING: Primary care settings in PEI. PARTICIPANTS: All active primary care physicians in PEI identified in the Canadian Medical Association database and medical office staff. Respondents included 63/88 (71.6%) physicians and 59/88 (67.0%) medical office staff. Fifty-seven physicians and medical office staff surveys overlapped. MAIN OUTCOME MEASURES: Attitudes and self-reported behaviours in CTI. RESULTS: More than 70% of the time, 68.3% of physicians reported asking new patients about their smoking behaviour and 66.7% reported that they listen to and acknowledge patients' feelings and fears about stopping smoking. Close to half (43.3%) of physicians reported thinking about or planning to do more CTI. Physicians and medical office staff reported that staff had limited involvement in methods to cue smoking interventions. Only half (50.8%) of physicians reported that their offices are well set up to identify smokers and to help them quit smoking. Offices were well set up for CTI if physicians perceived that office staff had an active role in CTI and if follow-up visits were frequently arranged. CONCLUSIONS: This study identified apparent opportunities for improving CIT, particularly in the areas of physician training, involvement of medical office staff, and awareness of billing codes. This could improve the quality of preventive care for patients in PEI.

Adult↗
PubMed1997

Coronal leakage of obturated root canals after long-term storage using a polymicrobial marker.

This in vitro study investigated the effect of long-term storage on the coronal leakage of a microbial marker on teeth root filled with lateral condensation of cold gutta-percha and one of two sealers. Sixty single-rooted teeth were prepared chemomechanically to a size 40 master apical file. The teeth were divided into two groups of 20 teeth each and obturated with gutta-percha using either Apexit or Tubliseal EWT sealer. The teeth were stored for 6 months in artificial saliva and tested for leakage using a marker consisting of S. sanguis and P. intermedia. The teeth were checked for bacterial leakage daily for 90 days. All positive control teeth leaked after 24 h, while the negative control teeth remained uncontaminated throughout the test period. Leakage reached the apex through the experimental teeth at the earliest at 17 days and at latest at 88 days. Fifty percent and 70% of the specimens of the Apexit and Tubliseal EWT groups respectively showed leakage at 90 days. There was no statistically significant difference (p > 0.05) between the two groups.

Calcium Hydroxide↗
PubMed1997

An evaluation of microbial coronal leakage in the restored pulp chamber of root-canal treated multirooted teeth.

This in vitro study investigated the effect of a resin-reinforced glass ionomer lining material on the coronal leakage of a mixed obligate microbial marker in maxillary molars obturated with lateral condensation of cold gutta-percha and Tubliseal sealer, after 2 years' storage. Forty maxillary first molars were prepared chemomechanically to a size 30-40 master apical file. The teeth were divided into an experimental group (30 teeth) and control group (10 teeth). In the experimental group, the floor of pulp chamber and the root-canal opening of 15 teeth were covered with Vitrebond as a lining; the remaining 15 teeth received no lining. These teeth were tested for leakage using a microbiological marker consisting of anaerobic streptococci and Fusobacterium nucleatum. The teeth were checked daily for bacterial leakage for 60 days. All positive control teeth leaked within 48 h, while the negative control teeth remained uncontaminated throughout the test period. The teeth restored with Vitrebond liner showed no leakage whilst 60% of the specimens with no Vitrebond liner showed leakage after 60 days.

Dental Cavity Lining↗
PubMed1997

Coronal leakage in teeth root-filled with gutta-percha and two different sealers after long-term storage.

This in vitro study investigated the effect of long-term storage on the coronal leakage of a microbial marker in teeth root-filled with lateral condensation of cold gutta-percha and one of two sealers. Sixty single-rooted teeth were prepared chemomechanically to a size 40 master apical file. The teeth were divided into two groups of 20 teeth each and obturated with gutta-percha using either Apexit or Tubliseal EWT sealer. The teeth were stored for 6 months in artificial saliva and tested for leakage using a marker consisting of Anaerobic streptococci and Prevotella intermedia. The teeth were checked for bacterial leakage daily for 90 days. All positive control teeth leaked within 48 hours, while the negative control teeth remained uncontaminated throughout the test period. Leakage in the experimental teeth started at times varying from 10 to 71 days; 30% and 75% of the specimens of the Apexit and Tubliseal EWT groups respectively showed leakage at 90 days. The Tubliseal EWT group showed significantly more leakage (p < 0.05) than the Apexit group.

Calcium Hydroxide↗
PubMed1997

A computerized adaptive testing system for speech discrimination measurement: the Speech Sound Pattern Discrimination Test.

A computerized, adaptive test-delivery system for the measurement of speech discrimination, the Speech Sound Pattern Discrimination Test, is described and evaluated. Using a modified discrimination task, the testing system draws on a pool of 130 items spanning a broad range of difficulty to estimate an examinee's location along an underlying continuum of speech processing ability, yet does not require the examinee to possess a high level of English language proficiency. The system is driven by a mathematical measurement model which selects only test items which are appropriate in difficulty level for a given examinee, thereby individualizing the testing experience. Test items were administered to a sample of young deaf adults, and the adaptive testing system evaluated in terms of respondents' sensory and perceptual capabilities, acoustic and phonetic dimensions of speech, and theories of speech perception. Data obtained in this study support the validity, reliability, and efficiency of this test as a measure of speech processing ability.

Adolescent↗
PubMed1996

An evaluation of the Nd:YAG laser in periodontal pocket therapy.

The aim of this study was to determine whether the Nd:YAG laser energies of 50 and 80 mJ at 10 pulses per second (pps) were capable of improving the clinical parameters associated with periodontal disease. These energy settings were chosen as previous work indicated that higher values would damage root surfaces and that 80 mJ had an in-vitro bactericidal effect. Eighty periodontally affected sites in teeth scheduled for extraction from 11 patients with adult periodontitis were randomly placed in one of the following four treatment groups: 1. laser treatment at 50 mJ, 10 pps for 3 minutes; 2. laser treatment at 80 mJ, 10 pps for 3 minutes; 3. scaling and 4. untreated control. Probing depth, bleeding on probing (BOP), plaque index, gingival index and gingival crevicular fluid (GCF) volume were measured at baseline and week 6. Baseline subgingival microbiological samples were collected, then repeated immediately after treatment and at week 6 to assess the total anaerobic colony forming units (CFU). Only the scaling group showed a significant reduction in pocket depth and BOP (P < 0.001). The microbial samples taken immediately after scaling and laser at 80 mJ and 10 pps treatments showed a significant reduction in total CFU compared with the baseline (P < 0.01), which was sustained only in the scaling group until week 6. Electron microscopy did not reveal any heat damage on the root surfaces. This study demonstrated that application of Nd:YAG laser pulses of 50 mJ and 80 mJ failed to improve the clinical and microbiological parameters of periodontal disease.

Adult↗
PubMed1996

Yes, minister, Canadians need strong tobacco-control legislation now!

At a meeting with federal health minister Diane Marleau on Nov. 16, 1995, the CMA and other health organizations were told that the minister plans to propose comprehensive measures to limit the manufacture, sale and marketing of tobacco products. On Dec. 11, 1995, the minister announced a "Blueprint on Tobacco Control," which outlined the scope of her plan to introduce tobacco legislation in the spring. On the basis of adamant support for tobacco control from all levels of the organization, the CMA urges the minister to move quickly. It also advocates regulating tobacco as a hazardous product in the meantime. Physicians can take a wide variety of actions to intervene with patients and add their voice to antitobacco lobbying efforts in 1996.

Canada↗
PubMed1996

Identifying hazardous or harmful alcohol use in medical admissions: a comparison of audit, cage and brief mast.

Two hundred and forty new medical inpatients received Alcohol Use Disorders Identification Test (AUDIT), CAGE and brief Michigan Alcoholism Screening Test (brief MAST) questionnaires. Sensitivities when identifying weekly drinkers of > 14 units (women) or > 21 units (men) were 93, 79 and 35%, respectively (P < 0.001). Sensitivities to > 21 units (women) or > 28 units (men were 100%, 94% and 47%. Routine screening of medical admissions with the AUDIT (cut-off score 8) is recommended.

Adolescent↗
PubMed1996

The effect of smear layer on microbial coronal leakage of gutta-percha root fillings.

The aim of this in vitro study was to determine the effect of removal of the smear layer on canal obturation as measured by penetration of bacteria from a coronal direction. One hundred and twenty extracted human teeth with straight, single root canals were decoronated. The canals were prepared using the modified double-flared technique with balanced force under copious irrigation. The apical matrix was prepared to size 40 and apical patency subsequently confirmed with a size 15 file. The teeth were divided randomly into experimental groups (80 teeth) and control groups (40 teeth). The root canals of 40 experimental and 20 control teeth were rinsed with 40% citric acid and 2% NaOCl to remove the smear layer before obturation. In experimental groups, 20 teeth with smear layer intact and 20 teeth with smear layer removed were obturated with lateral condensation of cold gutta-percha and Apexit sealer. A further 20 teeth with smear layer intact and 20 teeth with smear layer removed were obturated with the Trifecta technique with the same sealer. In control groups, 10 teeth with smear layer intact and 10 teeth with smear layer removed were obturated with lateral condensation of cold gutta-percha and Apexit sealer. These teeth were completely sealed both coronally and apically to serve as negative controls. The remaining 20 teeth with either smear layer intact or smear layer removed were not obturated and served as the positive controls. The root surface of each tooth was sealed with nail varnish. The cut end of a polypropylene tube was sealed around the coronal part of each root canal so that bacteria placed therein could move only through the obturated canal space. Each root was placed in a glass bottle containing sterile Todd-Hewitt Broth (THB) and aliquots of 0.5 ml of THB were injected into the polypropylene tube. The model system was centrifuged at 168 g. An innoculum of Streptococcus sanguis in THB was placed in each coronal chamber at 5-day intervals and daily observations were made for bacterial growth in the apical reservoir for 90 days. All positive control teeth showed bacterial penetration within 24 h, while the negative control teeth remained uncontaminated throughout the test period. Leakage through the experimental teeth was variable ranging from 7 to 86 days. There was no statistical significant difference (P > 0.05) in leakage between the obturated canal when the smear layer was either removed or intact.

Calcium Hydroxide↗
PubMed1996

An in vitro study of the coronal leakage of two root canal sealers using an obligate anaerobe microbial marker.

The aim of this in vitro study was to investigate the coronal leakage of obligate anaerobes into root canals obturated with lateral condensation of cold gutta-percha with two root canal sealers. Sixty extracted human teeth with straight, single root canals were prepared using the modified double-flared technique with balanced force under copious irrigation until the master apical file was size 40. The teeth were divided randomly into experimental groups (40 teeth) and control groups (20 teeth). In the experimental groups, 20 teeth were obturated with lateral condensation of cold gutta-percha and AH26 sealer and 20 teeth were obturated with the same technique using TubliSeal EWT sealer. In the control groups, 10 teeth were obturated with the same technique either with AH26 or TubliSeal EWT sealer. These teeth were completely sealed to serve as negative controls. The remaining 10 teeth were not obturated and served as positive controls. The root surface of each tooth was sealed with nail varnish except the apical 2 mm. The coronal part of each root canal was sealed with the cut end of polypropylene tube and placed in a glass bottle containing sterile Fastidious Anaerobe Broth (FAB). Aliquots of 0.5 mL of FAB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An inoculum of Fusobacterium nucleatum in FAB was placed in each coronal chamber at 7-day intervals and daily observations were made for bacterial growth in the apical reservoir for 12 weeks. All positive control teeth showed bacterial leakage within a week, while the negative control teeth remained uncontaminated throughout the test period. All the experimental teeth exhibited leakage of bacterial metabolites within 12 weeks, ranging from 1 to 12 weeks. The mean time for complete leakage in the AH26 and the TubliSeal EWT groups was 8.4 and 8.2 weeks respectively. There was no statistically significant difference (P > 0.05) in leakage between the AH26 and the TubliSeal EWT groups.

Bismuth↗
PubMed1993

Failure of the legal system to enforce drunk driving legislation effectively.

STUDY OBJECTIVE: To evaluate the investigation and prosecution of drunk drivers and identify reasons for system failure. DESIGN: Prospective data collection on all drivers with an elevated blood alcohol level who were treated at a Level I trauma center between January 1 and June 30, 1991. SETTING: Level I trauma center/university medical center serving a population of 1.8 million. INTERVENTIONS: Prospective data collection, interviewing ambulance squad members, investigating police, and results of prosecution. MEASUREMENTS AND MAIN RESULTS: Of 321 drivers, 78 had ethanol levels of more than 100 mg/dL; nine were between 50 and 100 mg/dL. All drivers had rapid transport to a trauma center for severe injury or high-risk injury mechanism. Police reports were accessible for 84 of 87 drivers; all drivers were believed to be at fault. The crashes resulted in five deaths and 74 other victims requiring hospitalization. Six of the intoxicated drivers died. Police requests for blood alcohol levels were made for 28 drivers, one of whom died. The remaining 59 drivers had no legal blood alcohol level drawn. Although the greater the distance from our center (more rural), the less likely were requests for ethanol levels, but there were many "no requests" from nearby cities. Of the 28 drivers on whom legal alcohol levels were drawn, eight escaped central registration with the highway safety commission, which records any and every traffic violation within New Jersey. Of the remaining 20, eight were not prosecuted (excluding one death), including one repeat offender. One committed a later "driving while intoxicated" offense and was then prosecuted. The remaining 11 were all convicted; five were repeat offenders. CONCLUSION: Reasonable cause is required for legal blood alcohol requests. Our data demonstrated that this is difficult when the driver is unavailable for questioning. However, once legal blood alcohol levels have been obtained, inadequate legal follow-up leads to nonprosecution. Once officially charged, conviction appears certain, but even this punishment and re-education fail to change behavior in many of these drivers.

Accidents, Traffic↗
PubMed1992

New hydroxyethylamine HIV protease inhibitors that suppress viral replication.

The synthesis of analogues of AcSerLeuAsn[Phe-HEA-Pro]IleValOMe (1, JG-365; where HEA stands for the hydroxyethylamine unit 2), a tight-binding inhibitor of HIVP, are reported. Systematic modification of the P3 and P3' regions of the inhibitors has led to smaller HIVP inhibitors that inhibit viral replication in HIV-infected and SIV-infected cell cultures. Six aliphatic and/or aromatic derivatives were prepared by replacing residues in the P3 regions of BocLeuAsn[Phe-HEA-Pro]IleValOMe. Aromatic side chains at P3 gave better inhibitors than aliphatic side chains. The better inhibitors in this series contained a beta-naphthylalanine or a biphenyl unit at P3. A second series of HIVP inhibitors were obtained by converting the P3 group into acyl groups. CbzAsn[Phe-HEA-Pro]IlePheOMe and Qua-Asn-[Phe-HEA-Pro]-Ile-Phe-OMe (where Qua = quinolin-2-ylcarbonyl) are potent HIVP inhibitors with Ki values equal to 1.0 and 0.1 nM, respectively. The inhibition constants were determined by using the continuous fluorometric assay developed by Toth and Marshall. The activities of the protease inhibitors for inhibition of SIV replication were determined in vitro using CEM x 174 cells. Inhibition of HIV infection was determined essentially as reported by Pauwels and co-workers. The anti-HIV assay was carried out in culture using CEM cells (a CD4+ lymphocyte line) infected with virus strain HTLV-IIIb with a multiplicity of infection of 0.1. Several analogues inhibited the cytopathic effect at concentrations of 0.1-0.8 microgram/mL. These results establish that good inhibitors of HIV protease that inhibit viral replication in infected lymphocytes in in vitro cell assays can be obtained from JG-365 when the AcSerLeu unit is replaced by aromatic acyl derivatives.

Amino Acid Sequence↗
PubMed1992

Pseudoaneurysm of the inferior gluteal artery.

Aneurysms of the inferior gluteal artery are uncommon, and have not previously been described in detail in the radiologic literature. The authors report the findings of computed tomography and angiography for a patient with a pseudoaneurysm of the inferior gluteal artery who was successfully treated by embolization alone.

Aged↗
PubMed1991

Control of intraocular pressure with apraclonidine hydrochloride after cataract extraction.

We conducted a randomly assigned, double-masked, controlled clinical trial to assess the efficacy of 1% apraclonidine hydrochloride in controlling postoperative intraocular pressure increases in patients undergoing extracapsular cataract extraction. Apraclonidine hydrochloride was given either one hour preoperatively or immediately after uncomplicated, extracapsular cataract extraction with posterior chamber intraocular lens implantation and compared with artificial tears given immediately postoperatively. Those who received apraclonidine hydrochloride preoperatively had significantly lower mean intraocular pressure at the first postoperative reading (P = .0005). After preoperative and postoperative apraclonidine hydrochloride, the mean early postoperative intraocular pressure was 19.8 mm Hg and 32.0 mm Hg, respectively, and 27.6 mm Hg after artificial tears. No patient who received preoperative apraclonidine hydrochloride had an intraocular pressure increase to 30 mm Hg or higher postoperatively. Nine of 20 patients (45%) who received postoperative apraclonidine hydrochloride and eight of 18 patients (44%) who received postoperative artificial tears had an increase of intraocular pressure to 30 mm Hg or higher in the early postoperative period. These differences were also highly significant (P = .0005).

Adult↗
PubMed1991

Oral candidosis in the elderly in long term hospital care.

A total of 137 patients in long term hospital care were interviewed and examined to determine the prevalence, nature and most important causes of oral candidosis in the hospitalized elderly. Oral candidal infection as determined by the imprint culture technique was present in 47% of patients with a further 31% being carriers of Candida. The prevalence of chronic atrophic candidosis in denture wearers was 38%, while 26% of all patients had angular cheilitis, 67% of which had an infective etiology. Microbiologic examination strongly indicated the upper denture as the major source of infection in those with dentures despite the existence of a ward policy which should have encouraged good oral and denture hygiene.

Aged↗