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Biomedical subjects

M Wood

Publications and source records attributed to M Wood.

At least 127 records · Page 7Linked to original sources
PubMed1996

Resin-bonded fixed partial dentures. I. Proposed standardized criteria for evaluation.

Since etched cast resin-bonded prostheses were introduced in 1980, many articles have been written about them. Most state that the reported clinical success of these bonded restorations has been based primarily on the longevity of the bonding. For a comprehensive evaluation, however, it is important not only to examine the bonding but also to evaluate the periodontal response. The proposed standard method provides a consistent and comprehensive evaluation of resin-bonded prostheses that is applicable for researchers and clinicians alike.

Dental Plaque Index↗
PubMed1996

Resin-bonded fixed partial dentures. II. Clinical findings related to prosthodontic characteristics after approximately 10 years.

A clinical study was conducted for patients who were functioning with resin-bonded fixed partial dentures for approximately 10 years. The purpose of this study was to evaluate the periodontal health and determine the prosthodontic characteristics of the fixed partial dentures. Results indicated that plaque indexes, probing, recession, and loss of attachment were greater for abutments than for control teeth. The differences were statistically significant but clinically small. The bonded restorations were generally well adapted and contoured for case of cleaning.

Chi-Square Distribution↗
PubMed1996

Tourists as inpatients in Queensland regional hospitals.

This study analysed medical record data from seven regional hospitals in Queensland to determine the types of medical conditions and injuries that resulted in overseas and interstate tourists being admitted to hospital. From a total of 135,128 admissions to the participating hospitals, 695 (0.51 per cent) were identified as overseas tourists and 3479 (2.57 per cent) were from interstate. The main reasons for admission of overseas tourists, based on principal diagnoses, were injuries and poisonings (37.6 per cent), circulatory disorders (11.7 per cent), digestive conditions (9.8 per cent), and genito-urinary disorders (8.8 per cent). For interstate tourists, the main reasons for admission were genito-urinary disorders (19.8 per cent), injuries and poisonings (15.4 percent), neoplasms (11.4 per cent) and circulatory disorders (10.6 per cent). These findings are discussed in relation to current literature in the field of travel medicine, emphasising the burden of care placed on the admitting hospital's resources, and the growing number of visitors to Queensland needing health care.

Catchment Area, Health↗
PubMed1996

Acyclovir and prednisolone treatment of acute infectious mononucleosis: a multicenter, double-blind, placebo-controlled study.

Ninety-four patients with infectious mononucleosis and symptoms < or = 7 days were randomized to treatment with oral acyclovir (800 mg 5 times/day) and prednisolone (0.7 mg/kg for the first 4 days, which was reduced by 0.1 mg/kg on consecutive days for another 6 days; n = 48), or placebo (n = 46) for 10 days. Oropharyngeal Epstein-Barr virus (EBV) shedding was significantly inhibited during the treatment period (P = .02, Mann-Whitney rank test). No significant effect was observed for duration of general illness, sore throat, weight loss, or absence from school or work. The frequency of latent EBV-infected B lymphocytes in peripheral blood and the HLA-restricted EBV-specific cellular immunity, measured 6 months after onset of disease, was not affected by treatment. Thus, acyclovir combined with prednisolone inhibited oropharyngeal EBV replication without affecting duration of clinical symptoms or development of EBV-specific cellular immunity.

Acyclovir↗
PubMed1996

Identification of human liver cytochrome P-450 3A4 as the enzyme responsible for fentanyl and sufentanil N-dealkylation.

Alfentanil, sufentanil, and fentanyl are synthetic opioids that are metabolized by oxidative N-dealkylation in the liver. We have previously shown that cytochrome P-450 3A4 (CYP3A4) contributes significantly to human liver microsomal alfentanil oxidation. Since identification of specific drug-metabolizing enzymes allows prediction of the variables affecting drug metabolism, the purpose of the present study was to identify the P-450 enzymes responsible for sufentanil and fentanyl metabolism in human liver microsomes. Microsomal preparations fortified with a reduced nicotinamide-adenine dinucleotide phosphate-generating system were incubated with 0.25 microM 3H-fentanyl or 3H-sufentanil. Rates of N-dealkylated metabolite formation significantly correlated with nifedipine oxidation activity (a marker of CYP3A4 activity) for fentanyl and sufentanil (r = 0.93 and 0.87, n = 18, respectively), but not with the oxidation activity for ethoxyresorufin (CYP1A2), S-mephenytoin (CYP2C19), bufuralol (CYP2D6), or chlorzoxazone (CYP2E1). Gestodene and troleandomycin (chemical inhibitors of CYP3A4) and antibody to CYP3A4 inhibited N-dealkylation of fentanyl and sufentanil. Chemical inhibitors of CYP2C, 2E1, and 2D6 did not inhibit N-dealkylation of fentanyl and sufentanil. Recombinant CYP3A4 expressed in Escherichia coli showed N-dealkylation activity of fentanyl and sufentanil, while expressed CYP1A2, 2C10, and 2E1 enzymes did not. We conclude that CYP3A4 is responsible for fentanyl and sufentanil N-dealkylation in vitro.

Analgesics, Opioid↗
PubMed1996

Effects of intraluminal and extracorporeal inferior vena caval bypass on canine hemodynamics.

OBJECTIVE: To compare inferior vena cava-right atrial extracorporeal bypass with intraluminal atriocaval shunting during hepatic vascular isolation. DESIGN: Prospective, randomized, controlled animal study. SETTING: University research laboratory. SUBJECTS: Adult mongrel dogs (n = 5) weighing 20 to 27 kg. INTERVENTIONS: Anesthetized dogs underwent laparotomy and sternotomy for vascular isolation. For atriocaval shunting, 20- and 24-Fr intraluminal shunts were inserted into the inferior vena cava via right atriotomy. For extracorporeal bypass, each animal underwent inferior vena cava, portal vein, and right atrial cannulation for venovenous bypass, utilizing a centrifugal pump. Hemodynamic data were recorded at baseline and at intervals after caval occlusion, Pringle maneuver, and caval occlusion with Pringle maneuver. MEASUREMENTS AND MAIN RESULTS: Isolated Pringle maneuver and caval occlusion with Pringle maneuver produced significant reductions in mean arterial pressure (MAP) and cardiac output, irrespective of pulmonary artery occlusion pressure. Extracorporeal bypass, including both caval and portal venous return, produced significant increases in MAP and cardiac output during caval occlusion with Pringle maneuver, while atriocaval shunting and extracorporeal bypass without portal venous return did not improve MAP or cardiac output. CONCLUSION: Venovenous extracorporeal bypass with portal return, acting as a right ventricular assist device, is superior to intraluminal atriocaval shunting in maintaining hemodynamic stability during hepatic vascular isolation.

Animals↗
PubMed1996

Lexipafant (BB-882), a platelet activating factor receptor antagonist, ameliorates mucosal inflammation in an animal model of colitis.

OBJECTIVE: To assess the anti-inflammatory action of lexipafant (BB-882), a platelet activating factor antagonist, in an animal model of acute colitis. DESIGN: An animal intervention study. METHODS: Following the rectal instillation of formalin 0.75% into male New Zealand White (NZW) rabbits, 0.85 ml of aggregated immunoglobulin was administered i.v. Treatment groups (0.8 mg/kg, n = 6; 2.4 mg/kg, n = 13; 3.2 mg/kg, n = 10) were given bolus doses of BB-882 two-hourly i.v. (control group, n = 25). Rectal dialysis was performed before induction of colitis and sacrifice. Dialysate leukotriene B4 (LTB4), prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) levels were determined. Tissue was saved for histology and measurement of myeloperoxidase content. RESULTS: There was a dose-dependent improvement in macroscopic scores (2.4 and 3.2 mg/kg: P < 0.02, P < 0.001) and myeloperoxidase levels (3.2 mg/kg: P < 0.04). Dialysate LTB4 levels fell (2.4 and 3.2 mg/kg: P < 0.03, P < 0.02) as did PGE2 levels. TXB2 concentrations remained unaffected. CONCLUSION: The PAF receptor antagonist BB-882 shows efficacy in treating inflammation in an animal model of acute colitis as evidenced by a dose-dependent fall in macroscopic mucosal damage, neutrophil infiltration and reduced generation of inflammatory mediators.

Animals↗
PubMed1996

Penetrating keratoplasty in Africa: graft survival and visual outcome.

AIM: To study the survival and visual outcome of penetrating keratoplasty in an African setting. METHODS: A retrospective analysis of 216 corneal grafts, performed on 203 eyes of 186 patients, at Kikuyu Hospital, Kenya over a 5 year period. RESULTS: Half of the transplants were carried out for keratoconus with only 5% of the grafts being undertaken for corneal scarring caused by trachoma or measles. The average follow up was 27.3 months. The probability of graft survival at 2 years was 87.4% (95% CI 80.6%-94.3%) for keratoconus and 64.7% (95% CI 54.8%-74.6%) for other corneal pathologies. Forty seven grafts (21.8%) in 36 patients (17.7%) are known to have become opaque. The commonest causes of graft opacification were bacterial keratitis (6.0%), endothelial failure (6.0%), and graft rejection (5.1%). Preoperatively 55% of keratoconus eyes and 75.7% of non-keratoconus eyes were blind. Postoperatively, 5% of keratoconus eyes and 41.7% of the non-keratoconus eyes were blind. Normal vision was achieved in 53.7% of operated eyes. Grafts carried out for keratoconus had a better visual outcome than grafts performed for other corneal pathologies. Preoperatively, 12.4% of keratoconus and 48.5% of non-keratoconus patients were blind in their better eye. Postoperatively, 1.1% of keratoconus patients and 25.7% of non-keratoconus patients were blind. The number of patients with normal vision in the better eye increased from 32 (17.2%) to 106 (57.0%). Sight was restored to 34 blind patients, but two patients with severe visual impairment preoperatively were blind at their last follow up. There was therefore a net reduction of 32 in the number of blind patients after 216 keratoplasties. CONCLUSIONS: Penetrating keratoplasty can be successful in Africa, particularly for keratoconus and other corneal dystrophies. However, penetrating keratoplasty has a limited role in the treatment of blindness from corneal scarring due to trachoma, measles, and vitamin A deficiency for which community based preventive measures must remain the priority.

Adolescent↗
PubMed1996

Changing patterns of investigation and treatment of cardiac failure in hospital.

OBJECTIVE: To assess the investigation and treatment of cardiac failure in 1995 and to compare this with management in 1992. DESIGN: Retrospective consecutive case study. SETTING: University teaching hospital. SUBJECTS: All patients (n = 265) discharged from Aberdeen Royal Infirmary in the first quarter (January 1-31 March) of 1995 with a diagnosis of congestive cardiac failure, left ventricular failure, or heart failure (unspecified). These correspond to the International Classification of Diseases 9th revision codings of 428.0, 428.1, and 428.9 respectively. METHODS: Sociodemographic and clinical data were extracted from the case notes of the above subjects and compared with similar data from the final six months of 1992. MAIN OUTCOME MEASURES: The use of echocardiography in confirming the diagnosis and delineating the aetiology of heart failure and the use of angiotensin-converting enzyme (ACE) inhibitors in the treatment of patients diagnosed as having heart failure and without contraindications to these agents. RESULTS: The number of patients discharged in 1995 with a diagnosis including cardiac failure had increased by 55.7% since 1992. The use of echocardiography had also risen from 36.6% to 72% (P < 0.0001) with an associated increase in the proportion of patients discharged on treatment with an ACE inhibitor (40% in 1992 v 55.1% in 1995: P < 0.001). The doses of ACE inhibitors used had also increased significantly (P < 0.001). Most patients with cardiac failure continue to be treated by general physicians, who are less likely to use echocardiography (P < 0.01) or prescribe an ACE inhibitor (P < 0.05) than cardiologists. CONCLUSIONS: There is increasing recognition, more thorough investigation, and improved treatment of heart failure. Despite this there are grounds for concern, both in terms of the adequacy of management and resource implications.

Aged↗
PubMed1996

Maximum likelihood estimates for the lifetime of bonded dental prostheses.

Clinical studies measuring the lifetime of dental prostheses produce censored data when not all specimens have failed during the course of the study. Such clinical data can be analyzed by the Weibull probability distribution function. Algorithms are presented that provide the maximum likelihood estimates of the distribution's parameters. These parameters are the characteristic lifetime (time to failure for 63% of the specimens of the total sample) and the Weibull or shape parameter. Two iterative methods for solving the maximum likelihood equations are given. These mathematical methods have been applied to the results from a retrospective clinical investigation into the lifetime assessment of resin-bonded prostheses. This study evaluated 164 resin-bonded prostheses (for 146 patients) placed between January, 1980, and May, 1985. To date (April, 1995), 47 prostheses (29%) have failed with a median time in service of 74 months (6.2 yr). For the surviving prostheses, the median time in service is 123 months (10.3 yr) and still increasing. The maximum likelihood estimate of the characteristic lifetime for these restorations is 255 months (21.3 yr). Differences in the characteristic lifetime were observed between prostheses placed anteriorly, 338 months (28 yr), and posteriorly, 207 months (17 yr). Since there are no rigorous confidence intervals for deeply censored samples, only provisional confidence bounds could be determined, which substantiated the observed differences. The Weibull modulus value of 1.5 indicates that the probability of failure for resin-bonded prostheses begins to decrease after 10 years in service.

Algorithms↗
PubMed1996

The effect of a diagnostic label of language delay on adults' perceptions of preschool children.

The effects of the label of expressive language disorder (ELD) on adults' perceptions of preschoolers were investigated. Twenty adults interacted with 3 children of typical development and one child previously diagnosed with ELD. Adults were randomly assigned to a label group (in which the child with ELD was identified) or a nonlabel group (in which the child with ELD was not identified). After interacting with dyads of children, adults ranked them according to behavioral characteristics and competencies. Results indicated that the nonlabel group ranked the child with ELD as significantly less likable and less productive, and they predicted less academic competence from her. In contrast, the label group did not differentiate the children behaviorally, but they predicted less social competence from the child with ELD. Implications regarding the use of labels in the inclusion of children with disabilities are discussed.

Adult↗
PubMed1996

Ten-year clinical and microscopic evaluation of resin-bonded restorations.

A clinical recall was conducted for 103 patients who were functioning with resin-bonded restorations for approximately 10 years. The purpose of this study was to evaluate marginal adaptation of the cast metal retainers. Following clinical evaluations, replicas of incisal and occlusal margins were examined in the scanning electron microscope to determine marginal separation and microscopic patterns of the resin composite interface between metal and tooth. Anterior abutments exhibited better clinical adaptation and fewer voids and debonds than did posterior abutments. Larger microscopic marginal separations were associated with those retainers that had clinically detectable voids or defects.

Chi-Square Distribution↗
PubMed1995

Biotransformation of tritiated fentanyl in human liver microsomes. Monitoring metabolism using phenylacetic acid and 2-phenylethanol.

Norfentanyl has been identified previously as a urinary metabolite of fentanyl. However, at clinically relevant concentrations, norfentanyl are below the limits of detection. The use of labeled drug in metabolic studies is a standard approach to overcome the limitations imposed by metabolite concentrations that are below detection limits. Unfortunately, the available tritium-labeled fentanyl yields unlabeled norfentanyl following N-dealkylation. Thus, we have developed a technique to monitor the N-dealkylation of fentanyl using the other products of N-dealkylation. The biotransformation of fentanyl was studied in human liver microsomes. After incubation with human liver microsomes for 20 min, almost 50% of a 0.03 microM concentration of [3H]-fentanyl was metabolized to the [3H]N-dealkylated metabolite phenylacetaldehyde, which was then converted principally to [3H]2-phenylethanol and to a smaller extent to [3H]phenylacetic acid in microsomal incubates. The apparent Km,app and Vmax,app for norfentanyl formation were 82 +/- 21 microM and 4.7 +/- 0.4 nmol product formed/min/nmol cytochrome P450, respectively. Thus, this study defined methodology that can be used to evaluate the metabolism of fentanyl, both in vivo and in vitro, at clinically relevant concentrations.

Analgesics, Opioid↗