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Biomedical subjects

D Mackenzie

Publications and source records attributed to D Mackenzie.

At least 19 recordsLinked to original sources
PubMed2005

Detection of bacteraemias during non-surgicalroot canal treatment.

UNLABELLED: Some dental procedures initiate a bacteraemia. In certain compromised patients, this bacteraemia may lead to distant site infections, most notably infective endocarditis. OBJECTIVE: To investigate whether a detectable bacteraemia was produced during non-surgical root canal therapy. METHODS: Thirty patients receiving non-surgical root canal therapy were studied. Three blood samples were taken per patient: pre-operatively, peri-operatively and post-operatively. In addition, a paper point sample was collected from the root canal. The blood samples were cultured by pour plate and blood bottle methods. The isolated organisms were identified by standard techniques. Blood samples were analysed for the presence of bacterial DNA by the polymerase chain reaction (PCR). In two cases where the same species of organism was identified in the root canal and the bloodstream, the isolates were typed by pulsed field gel electrophoresis (PFGE). RESULTS: By conventional culturing, a detectable bacteraemia was present in 9 (30%) of the 30 patients who had no positive pre-operative control blood sample. In 7 (23.3%) patients, the same species of organism was identified in both the bloodstream and in the paper point sample from the root canal system. Overall, PCR gave lower detection rates compared with conventional culture, with 10 of 90 (11%) of the blood samples displaying bacterial DNA. PFGE typing was undertaken for two pairs of culture isolates from blood and paper points; these were found to be genetically identical. CONCLUSIONS: Non-surgical root canal treatment may invoke a detectable bacteraemia.

Anti-Infective Agents, Local↗
PubMed2002

The effectiveness of various disinfectants used as endodontic intracanal medications: an in vitro study.

The purpose of this study was to compare in vitro the suitability of four disinfectants as intracanal medications: calcium hydroxide, chlorhexidine gel, chlorhexidine in the form of a controlled-release delivery system (PerioChip), and the combination of chlorhexidine gel with calcium hydroxide. Saline was used as the control. The disinfectants were tested at three different time periods (3, 8, and 14 days) by using human tooth specimens that had been previously contaminated with Enterococcus faecalis. Calcium hydroxide worked very efficiently in killing E. faecalis in the 3-day group and 8-day group. It was not as effective in the 14-day group. The different chlorhexidine formulations were also found to be effective for all time periods. More specifically, the combination of chlorhexidine gel with calcium hydroxide and the chlorhexidine gel worked slightly better than the PerioChip, but there was no significant difference among the medications.

Anti-Infective Agents, Local↗
PubMed2000

Pursestring closure of radial forearm fasciocutaneous donor sites.

BACKGROUND: The radial forearm fasciocutaneous free flap has become one of the most common methods of reconstructing defects after head and neck ablative surgery. The fasciocutaneous flap is an excellent replacement for the tissue that has been removed. Unfortunately, donor site morbidity remains a problem. Donor site morbidity is primarily related to poor skin graft take, cosmesis, and neural dysfunction. Decreasing the size of the donor site defect may allow for improved cosmesis with decreased morbidity. MATERIAL AND METHODS: Prospective evaluation of a pursestring closure of radial forearm fasciocutaneous donor sites over a 16-month period. RESULTS: Seventy-one radial forearm free flaps were used. Sixty-seven had a pursestring closure of the donor site. After flap elevation the mean size of the defect was 61 cm2 (range, 28-140 cm2). Pursestring closure decreased the mean of the defect to 34 cm2 (range, 10-104 cm2) (P <.0001). Defect size was decreased by a mean of 44.5% (range, 24.5%-66.7%) (P <.0001). COMPLICATIONS: The rate of skin graft loss (>25%) (9% of patients) was less than that reported in the literature. No patient required a second surgical procedure. Neural morbidity was equal in both groups. Cosmesis was much improved. CONCLUSIONS: Pursestring closure allowed for a significantly decreased donor defect, associated with better cosmesis and less skin graft loss.

Forearm↗
PubMed1998

Microbial factors and gingival crevicular fluid aspartate aminotransferase levels. A cross-sectional study.

The aim of this cross-sectional study was to investigate the clinical application of chairside tests for gingival crevicular fluid (GCF) aspartate aminotransferase (AST) levels and plaque BANA hydrolysis activity with the presence of the periodontal pathogens Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans. The study comprised 100 periodontitis sites (pocket depths > or =4 mm, GI=3) from 10 patients with chronic adult periodontitis and 100 control sites (pocket depths <4 mm, GI<3) from 10 periodontally healthy patients comprising 55 healthy sites (pocket depths <4 mm, GI=0) and 45 gingivitis sites (pocket depths <4 mm, GI=1 or 2). The values for both BANA hydrolysis and AST levels were significantly higher in samples from periodontitis compared with gingivitis and healthy sites (p<0.001). A. actinomycetemcomitans was identified in 45% and P. gingivalis in 17% of periodontitis sites but neither pathogen was recovered from control sites and there was no significant correlation with the clinical parameters measured. There was no significant relationship between the presence of P. gingivalis and/or A. actinomycetemcomitans with BANA hydrolysis or AST levels. A significant correlation (p=0.0017) was observed between BANA hydrolysis and pocket depth and between AST hydrolysis and the GI (p=0.01). This study failed to demonstrate a positive association between chairside analysis of GCF metabolites for AST levels and/or BANA hydrolysis with P. gingivalis and A. actinomycetemcomitans. However, the GCF metabolites had a significant correlation with periodontally diseased sites in patients with chronic adult periodontitis and may help confirm clinical observations.

Adult↗
PubMed1996

An assessment of microbial coronal leakage in teeth root filled with gutta-percha and three different sealers.

The aim of this in vitro study was to determine the effect of three different root canal sealers on the bacterial penetration of obturated root canals. Eighty 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 (60 teeth) and control groups (20 teeth). Twenty experimental teeth each were obturated by lateral condensation of cold gutta-percha with AH26, Apexit or Tubliseal EWT sealer. In the control groups, 10 teeth were obturated using the same technique with AH26, Apexit 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, except the apical 2 mm, was sealed with nail varnish. The coronal part of each root canal was sealed with the cut end of a polypropylene tube and placed in a glass bottle containing sterile Todd-Hewitt Broth (THB). Aliquots of 0.5 ml of THB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An innoculum of Streptococcus sanguis in THB was added to the tube 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 and negative control teeth remained uncontaminated throughout the test period. Leakage through the experimental teeth varied from 7 to 86 days. There was no statistically significant difference (P > 0.05) in leakage of the obturated canals between AH26, Apexit and Tubliseal EWT sealers.

Bismuth↗
PubMed1996

Comparison of polymerase chain reaction and culture methods for detection of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in subgingival plaque samples.

In this study, the major periodontal pathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were detected in subgingival plaque samples from patients with periodontal disease by polymerase chain reaction (PCR) and conventional culture methods. 170 plaque samples from 43 patients were analysed; A. actinomycetemcomitans and P. gingivalis were each detected in 40 (24%) of samples by PCR, whereas conventional culture methods detected A. actinomycetemcomitans and P. gingivalis in 25 (15%) and 18 (11%) of samples, respectively. The proportion of patients carrying A. actinomycetemcomitans in at least 1 sampled periodontal site was 17/43 (40%) by PCR and 13/43 (30%) by culture; for P. gingivalis this was 12/43 (28%) by PCR and 9/43 (21%) by culture. Only 5 samples, from 3 patients, harboured both A. actinomycetemcomitans and P. gingivalis. It is concluded that PCR is more accurate than conventional culture methods for identification of these periodontal pathogens in subgingival plaque samples and has a higher frequency of detection.

Aggregatibacter actinomycetemcomitans↗
PubMed1995

Monitoring the axilla in patients with silicone gel implants.

Migration of silicone beyond the breast implant capsule may occur as a result of silicone bleed, leak, or rupture, and it may indicate failure of implant envelope integrity. We report a series of 23 patients with silicone implants who had axillary lymph node biopsies for palpable masses. Group 1 (n = 15) had biopsies performed an average of 6 years following aesthetic augmentation, and Group 2 (n = 8) had biopsies performed an average of 5 years after mastectomy reconstruction. All biopsies demonstrated foreign body reaction consistent with silicone migration. Five patients in Group 1 and two in Group 2 also had breast cancer detected by the axillary biopsy. Evaluation of the axilla utilized a combination of one or more techniques, including mammography, ultrasonography, magnetic resonance imaging, and fine-needle aspiration. We conclude that (1) routine evaluation of the axilla is mandatory in all patients with silicone breast implants; (2) an algorithmic approach in diagnosing axillary masses may be helpful, especially in augmentation patients; and (3) axillary masses detected by clinical examination or other means must be biopsied, even in the face of negative screening studies, because breast cancer may be coincidental with a silicone granuloma.

Adult↗
PubMed1993

Isolation and preliminary characterization of the 14- to 18-kilodalton Candida albicans antigen as a phospholipomannan containing beta-1,2-linked oligomannosides.

Western blot (immunoblot) analysis of Candida albicans germ tube extracts has demonstrated the probable presence of beta-1,2-linked oligomannosides acting as epitopes distributed over a 14- to 18-kDa antigen unreactive to concanavalin A. These conclusions about the existence of these non-mannan-associated oligomannoside species were reinforced in the present study by the demonstration of reactivity of factor serum 5 (Iatron Laboratories) with the same antigen. A monoclonal antibody which reacted in an enzyme immunoassay with beta-1,2-linked oligomannosides converted into neoglycolipids and in Western blotting with the 14- to 18-kDa antigen from yeast and germ tubes, through metaperiodate-sensitive epitopes, was used for further characterization of the molecule. Reducing agents and strong protease digestion, which have deleterious effects on C. albicans proteins and mannoproteins, affected neither the antigenicity nor the relative molecular weight of the molecule. Western blots performed after migration of protease-treated extracts in polyacrylamide gels without sodium dodecyl sulfate (SDS) showed that the 14- to 18-kDa antigen could be negatively charged, whereas metabolic radiolabeling demonstrated that these charges could originate, at least in part, from the presence of phosphorus within the molecule. Chloroform-methanol-water extraction of protease-resistant material led to purification of the 14- to 18-kDa antigen, as determined by SDS-polyacrylamide gel electrophoresis and Western blotting. Metabolic radiolabeling with mannose confirmed the presence of these sugar residues within the purified 14- to 18-kDa antigen (despite its nonreactivity to concanavalin A), whereas radiolabeling with palmitic acid demonstrated its lipopolysaccharidic nature. Together, these results led to the conclusion that the 14- to 18-kDa antigen is a phospholipomannan.

Antibodies, Fungal↗
PubMed1992

Fecal alpha 1-antitrypsin clearance in the differential diagnosis of steatorrhea.

We reviewed the fecal fat excretion and alpha 1-antitrypsin clearance results of 160 patients with steatorrhea in whom a final diagnosis was obtained, based on history, physical examination, and radiological, functional and morphological tests. Twenty-two patients had pancreatic diseases and 138 had steatorrhea due to gastrointestinal diseases. alpha 1-antitrypsin clearance was invariably normal in chronic pancreatitis, but there was only a 23 to 50% of correct etiological classification when the combination of steatorrhea and normal alpha 1-antitrypsin clearance was present. However, none of our patients diagnosed of chronic pancreatitis had abnormal alpha 1-antitrypsin clearance. The combination of steatorrhea and normal clearance of alpha 1-antitrypsin was a modest clue for diagnosis of pancreatic malabsorption.

Celiac Disease↗
PubMed1980

Factors determining the passage of drugs from blood into saliva.

1. Following single oral dosing of ampicillin, cephalexin, tetracycline, erythromycin estolate, clindamycin and rifampicin to six normal volunteers, antibacterial activity was measured at 1, 3 and 6 h in serum, gingival fluid and minor gland saliva from all subjects and in parotid and submandiabular saliva from three. 2. pH values of all gingival fluid and saliva specimens were noted. 3. Partition coefficients between n-octanol and water were measured for erythromycin, clindamycin and rifampicin. Published data were used for ampicillin, cephalexin and tetracycline. 4. All antibiotics, but particularly rifampicin, were detected in gingival fluid. Only rifampicin and to a lesser degree, clindamycin were present in the other salivary constituents. 5. In studies of secretion of drugs in saliva, both the physico-chemical characteristics of the drugs and the physiological differences between individual salivary components should be considered. 6. Parotid saliva samples are likely to be of greatest value.

Adult↗