Search PubMed⌕ Search

Biomedical subjects

M Taylor

Publications and source records attributed to M Taylor.

At least 361 records · Page 20Linked to original sources
PubMed1998

Otoconia biogenesis, phylogeny, composition and functional attributes.

This work consolidates data about these interesting organic crystals of vertebrate inner ears. It addresses 5 aspects of inner ear otoliths not completely understood to date: 1) embryological data that explains the formation of the crystals, 2) the significance of the organic and the inorganic phase of the otolith and the changing patterns of otoconia formation along the evolutionary tree, 3) otoliths contribution for detecting linear acceleration, 4) the effect that altered gravity and aminoglycosides have on the development and adult shape of the crystals, and the evolutionary significance of a changing shape of the crystals from primitive forms (lamprey) to high vertebrate birds and mammals is discussed, 5) functional attributes of the otolithic organs and morphological modifications of the otoliths by physical and chemical insults are presented with an extensive discussion of the most relevant literature published and available to us.

Animals↗
PubMed1998

Maxillary sinus augmentation in the non-human primate: a comparative radiographic and histologic study between recombinant human osteogenic protein-1 and natural bone mineral.

The posterior maxilla has traditionally been one of the most difficult areas to successfully place dental implants due to poor bone quality and close approximation to the maxillary sinus. Sinus augmentation procedures have become a viable means of assuring adequate bone for the placement of dental implants in this area. However, with the techniques currently employed, a considerable variation in the quality of bone attained with the sinus augmentation procedure exists. The purpose of this in vivo study was to evaluate the healing response and bone formation stimulated by 3 doses of recombinant human osteogenic protein-1 (rhOP-1), 0.25, 0.6, and 2.5 mg OP-1 per gram of collagen matrix; natural bone mineral; or collagen matrix alone (control) placed in the maxillary sinus of adult chimpanzees. Results were assessed using clinical, histologic, and radiographic techniques. Radiographic analysis of the computed tomography scans taken at 1 week, and 2.5, 4.5, and 6.5 months revealed a more rapid mineralization with the 2.5 mg OP-1/g collagen matrix and natural bone mineral treatment groups. The incremental bone mineral density (BMD) increase for these 2 treatments from 1 week to 2.5 months was over 2.5 times the increase found with the collagen matrix alone; these 2 treatments also had a higher BMD at the most superior slices evaluated when compared to the other 3 groups. Biopsy specimens were taken at 3.5, 5.5, and 7.5 months and for all 5 treatment groups bone formation was observed at all time points in the majority of the specimens. At 7.5 months the 2.5 and 0.6 mg OP-1/g collagen matrix treatment groups had an increase in the percent bone area when compared to the matrix alone control. In conclusion, these results demonstrate that sinus augmentation with natural bone mineral or 2.5 mg OP-1/g collagen matrix induce comparable radiographic and histologic evidence of bone formation and that both of these treatments performed superior to the control group of collagen matrix alone based upon all methods of evaluation.

Analysis of Variance↗
PubMed1998

Residual lateral wall defects following sinus grafting with recombinant human osteogenic protein-1 or Bio-Oss in the chimpanzee.

Sinus grafting procedures are a viable means of ensuring adequate bone for the placement of dental implants in the posterior maxilla. In the quest to improve predictability and accelerate the time line toward receiving a final prosthesis, researchers have turned to recombinant human proteins like osteogenic protein-1 for the potential to therapeutically enhance bone formation. Bilateral sinus augmentations were performed in 15 adults chimpanzees to evaluate treatment with different doses of the osteogenic protein-1 device or natural bone mineral (Bio-Oss). Methods of evaluation included soft tissue healing, radiography (computed tomographic scan), histology, residual lateral wall defect surface area at 7.5 months, and the extent of soft tissue encleftation at 7.5 months. Findings revealed radiographic and histologic evidence of bone formation with all treatment groups and a statistically significant reduction in the depth of soft tissue encleftation and the residual lateral wall defect surface area for both the Bio-Oss and the 2.5-mg osteogenic protein-1 per gram collagen matrix treatments when compared to collagen matrix alone. These results suggest that Bio-Oss and the 2.5-mg osteogenic protein-1 per gram collagen matrix effectively stimulate bone formation in the maxillary sinus.

Analysis of Variance↗
PubMed1998

Trapezoid dislocation with a Galeazzi fracture.

A case of volar trapezoid dislocation and Galeazzi fracture in a 28-year-old man is presented. This case illustrates some of the problems associated with diagnosis and treatment of this rare injury.

Adult↗
PubMed1998

High level simulators in medical education.

There are now two high level simulator centres in the UK. In both the central feature is a human patient simulator. In this article the concept, application and value of such systems in medical education will be described.

Education, Medical↗
PubMed1997

A phase I pilot study of pelvic radiation and alpha-2A interferon in patients with locally advanced or recurrent rectal cancer.

PURPOSE: The purpose of this pilot study was to determine the maximum tolerated dose of alpha-2a interferon given by subcutaneous injection and combined with high dose pelvic radiation for locally advanced or recurrent rectal cancer. METHODS AND MATERIALS: In this Phase I pilot study, patients with locally advanced, unresectable, or recurrent rectal cancer with or without distant metastases received external beam pelvic radiotherapy over 5 to 6 weeks combined with escalating doses of alpha-2a interferon. Interferon was escalated in increments of 3 million units for each patient cohort, starting at 3 million units subcutaneously 3 days weekly during pelvic radiation. Radiotherapy consisted of 44 Gy (2 Gy fractions) to the pelvis followed by a boost of 6 Gy or 16 Gy to gross pelvic tumor, depending on the presence or absence of small bowel in the boost field, respectively. Between 1991 and 1993, 10 patients were treated on this study, five with locally advanced and five with locally recurrent rectal cancer. RESULTS: At 6 million units of interferon, Grade 3 (WHO criteria) toxicities were as follows: diarrhea (one), leukopenia (one), and neutropenia (one). One patient died of a massive GI bleed at this dose level. Death was not felt to be treatment related. The maximum tolerated dose of interferon was 3 million units three times weekly with radiation. Three patients had unusual complications at 4, 6, and 6 months possibly related to treatment. The first had a right distal ureteric stricture with a right urinoma. The second had a sudden left foot drop that has remained stable. The third had sudden onset of bilateral lower extremity paraplegia with spontaneous resolution. CONCLUSIONS: The maximally tolerated dose of interferon alpha-2a given three times weekly during pelvic radiation was 3 million units based on acute side effects. Nevertheless, even at this dose level there were three unusual subacute complications possibly related to treatment. Caution is advised when combining interferon alpha-2a with high dose pelvic radiation, especially in patients with predisposing conditions (such as diabetes) for radiotherapy complications.

Aged↗
PubMed1997

A study of prognostic factors for hepatic resection for colorectal metastases.

BACKGROUND: Liver resection is accepted treatment for selected patients with colon cancer metastatic to the liver. There remains some controversy regarding the selection criteria, particularly which preoperative features are useful predictors of long survival postresection. METHODS: One hundred and twenty-three patients who had liver resection for colorectal metastases on the Hepato Pancreatic Biliary Service at The Toronto Hospital between August 1977 and June 1993 were studied. Seventy-seven had solitary lesions, 15 had single lesions with satellite nodules, and 31 had multiple lesions. Synchronous liver metastases were found in 40 patients and 83 patients had metachronous lesions. Fifty-one patients had formal lobectomies and 21 had extended lobectomies. RESULTS: Postoperative complications were seen in 28% of patients, but there were no operative or postoperative deaths. Overall actuarial 5-year survival was 34%. There was a significant difference in survival according to the number of metastases. Patients with single lesions had a 5-year survival of 47% compared with 16% for single lesions with satellite nodules, and 17% for multiple lesions. There were no significant differences in survival based on age, sex, synchronous versus metachronous lesions, status of lymph nodes at the time of original surgery, intraoperative blood replacement, or size of tumor. CONCLUSIONS: An aggressive approach to the surgical management of colorectal liver metastases is possible with low risk in centers specializing in liver surgery, and results in prolonged survival in one third of patients. The most reliable predictor of long-term survival is the number of metastases in the liver.

Adult↗
PubMed1997

A phase II study of mitomycin C and oral etoposide for advanced adenocarcinoma of the upper gastrointestinal tract.

BACKGROUND: Mitomycin C and etoposide have both demonstrated activity against gastric carcinoma. Etoposide is a topoisomerase II inhibitor with evidence for phase-specific and schedule-dependent activity. PATIENTS AND METHOD: Twenty-eight consecutive patients with advanced upper gastrointestinal adenocarcinoma were treated with intravenous (i.v.) bolus mitomycin C 6 mg/m2 on day 1 every 21 days to a maximum of four courses. Oral etoposide capsules 50 mg b.i.d. (or 35 mg b.i.d. liquid) were administered days 1 to 10 extending to 14 days in subsequent courses if absolute neutrophil count > 1.5 x 10(9)/l on day 14 of first course, for up to six courses. RESULTS: Twenty-six patients were assessed for response of whom 12 had measurable disease and 14 evaluable disease. Four patients had a documented response (one complete remission, three partial remissions) with an objective response rate of 15% (95% confidence interval (95% CI) 4%-35%). Eight patients had stable disease and 14 progressive disease. The median survival was six months. The schedule was well tolerated with no treatment-related deaths. Nine patients experienced leucopenia (seven grade II and two grade III). Nausea and vomiting (eight grade II, one grade III), fatigue (eight grade II, two grade III) and anaemia (seven grade II, two grade III) were the predominant toxicities. CONCLUSION: This out-patient schedule is well tolerated and shows modest activity in the treatment of advanced upper gastrointestinal adenocarcinoma. Further studies using protracted schedules of etoposide both orally and as infusional treatment should be developed.

Adenocarcinoma↗
PubMed1997

Pro-haemorrhagic effects of calcium antagonists: a comparison of isradipine and atenolol on ex vivo platelet function in hypertensive subjects.

It has been suggested that long term treatment with calcium antagonist drugs might inhibit platelet function and lead to an anti-atheromatous effect. However recent data have also suggested that such an effect might increase mortality due to an increased incidence of gastrointestinal bleeding. We identified 43 subjects from general practice with uncomplicated mild to moderate hypertension to compare the effects of the calcium antagonist isradipine with that of the beta-blocker atenolol on platelet function, plasma beta-thromboglobulin levels, fibrinolysis, and serum lipids in a randomised double-blind parallel group study. After careful evaluation to exclude concomitant aspirin use, only 24 subjects were eligible to enter the study. While isradipine and atenolol produced comparable and clinically significant falls in blood pressure (167 +/- 2/102 +/- 1 to 153 +/- 3/91 +/- 2 mm Hg, and 165 +/- 2/101 +/- 1 to 156 +/- 4/91 +/- 2 mm Hg, respectively), neither drug produced a detectable effect on ex vivo platelet aggregation, platelet retention, or thromboxane generation with adrenaline, collagen, adenosine-di-phosphate, or platelet activating factor. However a decrease in plasma beta-thromboglobulin levels was observed which reached statistical significance (P < 0.05) after 12 weeks treatment in the isradipine but not the atenolol group. A 39% reduction with isradipine compared with 34% following atenolol treatment. Euglobulin clot lysis time was not altered by either drug. Serum cholesterol concentrations were also unaltered by drug treatment. Therapeutic doses of the calcium antagonist isradipine may produce a minor indirect effect on platelet function after several weeks of treatment. However, this is of doubtful clinical importance and may simply reflect an effect of lowered blood pressure on platelet function.

Adrenergic beta-Antagonists↗
PubMed1997

Assessing literacy for patient teaching: perspectives of adults with low literacy skills.

The purpose of this qualitative study was to gain an understanding of the response of English speaking adults with low literacy skills to screening of reading ability in order to facilitate the planning of patient teaching in a hospital setting. The Rapid Estimate of Literacy in Medicine (REALM) was the screening tool used to provide a screening experience for research subjects. A multiple case study design was employed to gain insight, describe participant experiences and generate an evidence-based conceptual model. While all participants supported the principle of screening in the context of the hospital, response to the actual experience was varied. Factors found to influence responses to screening included perceived risks of illiteracy exposure, perceived risks of non-disclosure during hospitalization and the attribution of characteristics to the hospital leading to it's designation as a 'special' place. A conceptual model of screening response was developed and compared to the Health Belief Model and Knox's Proficiency Theory of adult learning. Implications for the health professions are also discussed.

Adult↗
PubMed1997

Does thiopentone delay recovery in children premedicated with midazolam?

This prospective, randomized trial of paediatric surgical outpatients, premedicated with oral midazolam, was designed to determine if an intravenous thiopentone induction of anaesthesia prolongs postoperative recovery compared to an inhalation induction with halothane. One hundred children, one to ten years of age, undergoing ENT surgical procedures of 30-60 min duration received midazolam 0.5 mg.kg-1 with atropine 0.03 mg.kg-1 and were randomized to either halothane (Group 1, n = 50) or a thiopentone induction (Group 2, n = 50) technique, followed by a standardized anaesthetic-protocol. Time to extubation was significantly greater in the thiopentone group (8.8 +/- 4 min vs 7.1 +/- 3 min, P < 0.05). Patients receiving thiopentone were also more sedated than the halothane group on arrival in the PARR (3.9 +/- 1.5, 3.3 +/- 1.7, respectively P < 0.05), but the differences disappeared after 30 min. Children premedicated with oral midazolam who receive an intravenous thiopentone induction have a slightly prolonged emergence from anesthesia compared to children induced with halothane.

Adjuvants, Anesthesia↗
PubMed1997

Fluconazole tolerance in clinical isolates of Cryptococcus neoformans.

Eleven isolates of Cryptococcus neoformans were investigated to determine the biochemical basis of their tolerance to fluconazole. The MICs of fluconazole for three isolates with low-level resistance were 3- to 6-fold higher than those for sensitive isolates, while the MICs for four isolates with high-level resistance were 100- to 200-fold higher than those for sensitive isolates. The level of ergosterol present in the isolates varied, and those which had relatively low levels of ergosterol were resistant to amphotericin B. Changes in the affinity of the target enzyme (sterol 14alpha-demethylase) and decreases in the cellular content of fluconazole seemed to be responsible for the resistance in isolates with low-level and high-level resistance, respectively.

Amphotericin B↗