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Biomedical subjects

C Bentley

Publications and source records attributed to C Bentley.

At least 19 recordsLinked to original sources
PubMed2001

Estimating the impact on prostate cancer mortality of incorporating prostate-specific antigen testing into screening.

OBJECTIVES: Whether early detection using prostate-specific antigen (PSA) and digital rectal examination (DRE) compared with DRE alone will reduce prostate cancer mortality awaits the results of ongoing prospective randomized trials. However, the impact that early detection could have on prostate cancer-specific survival can be estimated by assuming that PSA failure after radical prostatectomy (RP) will translate into death from prostate cancer. METHODS: The study population consisted of 1274 men with clinically localized prostate cancer who underwent RP in Boston, Massachusetts or Philadelphia, Pennsylvania between 1989 and 2000 and had a preoperative PSA level greater than 4 but not more than 10 ng/mL. The primary endpoint was actuarial freedom from PSA failure (defined as PSA outcome). RESULTS: The relative risk of PSA failure after RP for patients diagnosed with a PSA of greater than 4 to 5, 5 to 6, 6 to 7, or 7 to 8 ng/mL compared with greater than 8 up to 10 ng/mL was 0.3 (95% confidence interval [CI] 0.2 to 0.5), 0.5 (95% CI 0.4 to 0.8), 0.6 (95% CI 0.4 to 0.9), or 0.9 (95% CI 0.6 to 1.3), respectively. On the basis of the estimates of the 5-year PSA outcome, patients with a biopsy Gleason score of 5 or 6 (781 of 1274; 61%) consistently benefited from RP performed when the PSA at diagnosis was greater than 4 to 7 ng/mL compared with greater than 8 to 10 ng/mL (93% versus 78%, P <0.0001). A benefit to early detection was not found for the vast majority (266 of 312; 88%) of patients who had a biopsy Gleason score of 7 or higher. CONCLUSIONS: Early detection using both PSA and DRE-based screening may benefit men who present with biopsy Gleason score 5 or 6 prostate cancer and a PSA level greater than 4 to 7 ng/mL compared with greater than 8 up to 10 ng/mL. This finding awaits validation from ongoing prospective randomized trials.

Actuarial Analysis↗
PubMed2001

Squint surgery in the over sixties.

We examined the indications for strabismus surgery in patients 60 years of age or older. A retrospective review was carried out of 111 case records of such patients operated on between January 1992 and May 1999. There were 59 females and 52 males, ranging in from 60 to 90 years (mean 67.3 years). The diagnoses were varied: the largest groups were cranial nerve palsies and consecutive strabismus. Fifty-six patients demonstrated binocular potential pre-operatively and 60 post-operatively. Twenty-three patients underwent reoperation. Twenty-eight patients also received botulinum toxin. The mean follow-up was 15 months, 54 patients were discharged within 6 months. Elective strabismus surgery in this age group constituted 7% of strabismus surgery activity (single surgeon). There were no complications. There is a demand for strabismus surgery in this ever increasing age group.

Aged↗
PubMed2001

Adjustable squint surgery in children.

The adjustable suture technique in adult strabismus surgery is well established. The aim of this study was to assess its feasibilty/outcome in a younger age group. A retrospective review of 359 case notes of patients, under the age of 16 years, who underwent squint surgery between 1992 and 1999 was carried out. Of these, 45 (13%) had undergone surgery with the adjustable suture technique. Post-operatively, 34 patients achieved an angle of +/- 10 pd and required no further treatment. We sought co-operation from the parents and encouraged their active participation during adjustment. It was not necessary for any child to return to the operating theatre to finalise adjustment. We conclude that this is an effective treatment in motivated children, as 76% (34/45) obtained an excellent result.

Adolescent↗
PubMed2001

Nightguard vital bleaching: a long-term study on efficacy, shade retention. side effects, and patients' perceptions.

BACKGROUND: The scientific literature is lacking in long-term clinical data on the duration of efficacy and post-treatment side effects of nightguard vital bleaching. PURPOSE: This longitudinal clinical study was undertaken (1) to determine the clinical efficacy and duration of efficacy at 3, 6, and 47 months post treatment of a peroxide-containing whitening solution; (2) to evaluate safety issues with respect to using a peroxide whitening solution; and (3) to determine patients' perceptions of the whitening technique. MATERIALS AND METHODS: This project was part of a nightguard vital bleaching study involving human participants. The study teeth for efficacy and duration of efficacy when using a 10% carbamide peroxide solution were the four maxillary central and lateral incisors, with the tooth shade being taken from the middle third of the tooth. Safety issues evaluated were the changes in gingival index (GI), plaque index (PI), nonmarginal gingival index (NMGI), nongingival oral mucosal index (NGOMI), and tooth vitality (TV). Radiographic changes of the study teeth and the patients' perceptions of tooth sensitivity (TS) or gingival irritation (Girr) during treatment and post treatment were also evaluated. RESULTS: The active 10% carbamide peroxide whitening solution used in this study was effective in lightening teeth (98%), and this effect was sustained at a mean of 47 months post treatment in 82% of the participants. When evaluating safety issues, 66% of the participants using the active solution reported TS or Girr. No one reported TS or Girr or any other adverse effects at the end of the study. CONCLUSIONS: The results of this study concur with those of previously reported studies that nightguard vital bleaching using a 10% carbamide peroxide whitening solution according to the manufacturer's instructions is efficacious and safe, with minimal side effects. In addition, long-term shade retention was reported by 82% of the participants at the end of the study, with no adverse side effects. CLINICAL SIGNIFICANCE: Results of this study should reassure dentists that nightguard vital bleaching is a safe, effective, and predictable method to lighten teeth. The whitening effect lasted up to 47 months in 82% of the patients, with no adverse side effects reported at the end of the study.

Adolescent↗
PubMed1999

Ocular abnormalities in Alagille syndrome.

OBJECTIVE: To assess the type and frequency of ocular abnormalities occurring in Alagille syndrome (AS) in a large group of affected patients and their parents and the potential pathogenetic role of fat-soluble vitamin deficiency. DESIGN: Observational case series. PARTICIPANTS: Twenty-two children with AS and 23 of their parents participated. MAIN OUTCOME MEASURES: Participants underwent full ophthalmic examination, including refraction, orthoptic examination, keratometry, slit-lamp examination, and funduscopy. Corneal diameter measurement was performed in a subset of nine and fluorescein angiography in a subset of six. Serum levels of vitamins A and E and cholesterol were measured. RESULTS: The most common ocular abnormalities in patients with AS were posterior embryotoxon (95%), iris abnormalities (45%), diffuse fundus hypopigmentation (57%, a previously unreported finding), speckling of the retinal pigment epithelium (33%), and optic disc anomalies (76%). Microcornea was not associated with large refractive errors, and visual acuity was not significantly affected by these ocular changes. Vitamin levels were normal. Ocular abnormalities including posterior embryotoxon, iris abnormalities, and optic disc or fundus pigmentary changes were detected in one parent in 36% of cases. CONCLUSIONS: Alagille syndrome is associated with a characteristic group of ocular findings without apparent serious functional significance and probably unrelated to fat-soluble vitamin deficiency. Simple ophthalmic examination of children with neonatal cholestatic jaundice and their parents should allow early diagnosis of AS, eliminating the need for extensive and invasive investigations.

Abnormalities, Drug-Induced↗
PubMed1999

Quantitation of vital bleaching by computer analysis of photographic images.

BACKGROUND: The authors investigated the use of computer processing of photographic images to monitor changes in tooth brightness after nightguard vital bleaching, or NGVB. METHODS: Photographs of shade guides and clinical cases (patients' teeth) were taken on 35-millimeter film with electronic flash illumination and processed commercially. A slide scanner was used to digitize images as red, green and blue, or RGB, files, with constant brightness, contrast and linearity settings; the images were then analyzed with commercial software. Relevant image components (that is, teeth or shade guide tabs) were separated, and histograms of various numerical color descriptors were generated for each image component. RESULTS: Analysis of shade tab images showed that the mean pixel intensity for the RGB blue channel, or MPIb, was the most satisfactory brightness descriptor, with clear sequential MPIb increments from lighter to darker shades in each series of colors (A through D) and close correlation with the manufacturer's brightness scale (r = .83). Mathematical analysis of MPIb data for shade tabs in the same image yielded a brightness index that was reproducible and correlated well with the manufacturer's brightness scale. Sequential measurements of this index in three subjects whose teeth were bleached with carbamide peroxide for 14 days correlated well with assessments made by visual shade guide comparisons. CONCLUSIONS: The authors conclude that computer analysis of digitized photographic images with internal color controls provides an index of tooth brightness that is reproducible from image to image. CLINICAL IMPLICATIONS: A brightness index derived from computer analysis of digitized photographic images may be useful for monitoring the effectiveness of NGVB.

Carbamide Peroxide↗
PubMed1995

A randomized study of the influence of perfusion technique and pH management strategy in 316 patients undergoing coronary artery bypass surgery. I. Mortality and cardiovascular morbidity.

UNLABELLED: The impact of perfusion technique and mode of pH management during cardiopulmonary bypass has not been well characterized with respect to postoperative cardiovascular outcome. METHODS: This double-blind, randomized study comparing outcomes after alpha-stat or pH-stat management and pulsatile or nonpulsatile perfusion during moderate hypothermic cardiopulmonary bypass was undertaken in 316 patients undergoing coronary artery bypass operations. RESULTS: Cardiovascular morbidity and mortality were not affected by pH management, and the incidence of stroke (2.5%) did not differ between groups. Overall in-hospital mortality was 2.8%, eight of the nine deaths occurring in the nonpulsatile group (5.1% versus 0.6%; p = 0.018). The incidence of myocardial infarction was 5.7% in the nonpulsatile group and 0.6% in the pulsatile group (p = 0.010), and use of intraaortic balloon pulsation was significantly more common in the nonpulsatile group (7.0% versus 1.9%; p = 0.029). The overall percentage of patients having major complications was also significantly higher in the nonpulsatile group (15.2% versus 5.7%; p = 0.006). Duration of cardiopulmonary bypass, age, and use of nonpulsatile perfusion all correlated significantly with adverse outcome. CONCLUSIONS: Use of pulsatile perfusion during cardiopulmonary bypass was associated with decreased incidences of myocardial infarction, death, and major complications.

Aged↗
PubMed1995

A randomized study of the influence of perfusion technique and pH management strategy in 316 patients undergoing coronary artery bypass surgery. II. Neurologic and cognitive outcomes.

UNLABELLED: This double-blind, randomized comparison of pulsatile or nonpulsatile perfusion and alpha-stat or pH-stat management during cardiopulmonary bypass was designed to assess postoperative central nervous system outcomes. METHODS: Neurologic and cognitive testing was conducted before the operation and 7 days and 2 months after the operation in 316 patients having coronary artery bypass and in a reference cohort of 40 patients having major vascular and thoracic operations. RESULTS: As detailed in part I of this study, mortality in patients having coronary bypass was 2.8%. The incidence of stroke was 2.5% and did not differ among bypass groups. Mortality was 2.5% for the major surgery cohort. The incidence of cognitive (p = 0.003) and either neurologic or cognitive dysfunction (p = 0.0002) was higher at 7 days for the coronary bypass group than for the major surgery cohort. The incidence of neurologic dysfunction remained higher (p = 0.050) at 2 months in the coronary bypass group. Cognitive dysfunction at 2 months was less prevalent after 90 minutes of cardiopulmonary bypass in patients managed with alpha-stat than with pH-stat strategy (27% versus 44%, p = 0.047). CONCLUSIONS: Postoperative central nervous system dysfunction is more prevalent in patients having coronary bypass than in those having major operations. Pulsatility has no effect on central nervous system outcomes, but alpha-stat management is associated with a decreased incidence of cognitive dysfunction in patients undergoing prolonged cardiopulmonary bypass.

Aged↗
PubMed1994

Antipodal alpha-N-(methyl through decyl)-N-normetazocines (5,9 alpha-dimethyl-2'-hydroxy-6,7-benzomorphans): in vitro and in vivo properties.

The enantiomeric (-)- and (+)-N-(methyl through decyl) normetazocines (5,9 alpha-dimethyl-2'-hydroxy-6,7-benzomorphans) were synthesized and their in vitro and in vivo activities determined. Increasingly bulky enantiomeric N-alkyl homologs were prepared until their interaction with the sigma 1 receptor decreased and their insolubility became a hindrance to their evaluation in vivo and/or in vitro. The (-)-methyl, -pentyl, -hexyl, and -heptyl homologs were essentially as potent as, or more potent than, morphine in the tail-flick, phenylquinone, and hot-plate assays for antinociceptive activity; the (-)-propyl homolog had narcotic antagonist activity between that of nalorphine and naloxone in the tail-flick vs morphine assay, and it also displayed antagonist properties in the single-dose suppression assay in the rhesus monkey. The antinociceptively potent (-)-heptyl homolog did not substitute for morphine in monkeys but did show morphine-like properties in a primary physical-dependence study in continuously infused rats. All five potent compounds showed high affinity for the mu opioid receptor from both rat and monkey preparations and the kappa opioid receptor (< 0.05 microM), and all except the (-)-methyl homolog interacted reasonably well at the delta receptor (K(i) < 0.1 microM). The (-)-propyl compound was equipotent (K(i) 1.5-2.0 nM) at mu and kappa receptors. The pattern of interaction of the (-)-enantiomeric homologs with mu receptors from rat and monkey preparations was similar, but not identical. The enantioselectivity of the homologs for mu receptors was greater in the rat than in the monkey preparation for all but the N-H and butyl compounds, and the enantioselectivity of the lower homologs (methyl through butyl) for the mu (monkey) receptor was greater than for the kappa or delta receptors. However, bulkier homologs (hexyl through decyl) displayed higher enantioselectivity at kappa or delta receptors than at the mu (monkey) receptor. The (+)-butyl through (+)-octyl homologs were essentially equipotent with, or more potent than, (+)-pentazocine at the sigma receptor. Only the (+)-H and (+)-methyl homologs had high affinity (< 0.05 microM) at PCP binding sites.

Amino Acid Sequence↗
PubMed1990

Reasons for restoration replacement: differences in practice patterns.

Patients receive varying types and amounts of restorative treatment, depending on the prescribing dentist. The aim of this study was to enhance the understanding of the variation of the restoration replacement practices of dentists. Three dentists in private practice in similar semirural communities with comparable practice demographics were asked to gather data on all restorations they replaced over a period of 1 month. They recorded the tooth number, number of restored surfaces, restorative material being replaced, number of surfaces in the replacement restoration, the replacement restorative material, and the reasons for the replacement restoration. Statistically significant differences were found among the dentists as to the reasons for posterior restoration replacement, replacement materials used, and increase in size of the replacement restorations. Differences were attributed to individual practice philosophies, demonstrating that clinical information was not the sole determining factor as to type of replacement restorations that patients received.

Composite Resins↗