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Biomedical subjects

R P Wilson

Publications and source records attributed to R P Wilson.

At least 37 records · Page 2Linked to original sources
PubMed1997

General practice fundholders' prescribing savings in one region of the United Kingdom, 1991-1994.

Since 1991, fundholding general practitioners in the UK have had a financial incentive to contain prescribing costs. Research has confirmed that fundholding practices have contained their prescribing costs more effectively than non-fundholding practices, but how much fundholders have actually saved by changing their prescribing is difficult to quantify. Fundholders are allocated a prescribing budget, and the underspend on this budget has been taken to represent savings produced by changing prescribing behaviour. However, this assumes accuracy of budget setting, which has been questioned. The objective of this study was to estimate the true savings in prescribing made by fundholders during the first 3 years of fundholding, without making assumptions about the accuracy of budget setting. We compare this to underspends on prescribing budgets. The results suggest that budget setting did not give fundholders over-generous budgets and that budget underspends are justified by the true savings in prescribing.

Budgets↗
PubMed1997

Mitomycin-C supplemented trabeculectomy, phacoemulsification, and foldable lens implantation.

PURPOSE: To evaluate the outcome of combined mitomycin-C filtering surgery, phacoemulsification, and foldable intraocular lens (IOL) implantation. SETTING: Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, USA. METHODS: This retrospective study evaluated 182 eyes of 174 patients who had combined mitomycin-C trabeculectomy, phacoemulsification, and insertion of a foldable IOL through a 3.5 mm incision. Success of the combined procedure was defined as intraocular pressure (IOP) below 21 mm Hg, with or without medications, and no serious complication. Success rates were calculated using the Kaplan-Meier actuarial method. RESULTS: Mean follow-up was 16.7 months +/- 5.4 (SD). The probability of success at 6, 12, 18, and 24 months was 98.3, 95.6, 90.6, and 88.0%, respectively. When compared with preoperatively, visual acuity improved one or more lines in 148 eyes (81.3%) and worsened one or more lines in 15 (8.2%); 111 eyes (61.0%) achieved visual acuity of 20/40 or better. The most frequent complication was posterior capsule opacification requiring capsulotomy, which occurred in 22 cases (12.0%). CONCLUSION: The 1 year and 2 year IOP control rate of combined mitomycin-C filtering procedures and phacoemulsification in glaucoma patients was high.

Aged↗
PubMed1997

Focal corneal decompensation caused by an anterior capsulotomy remnant.

Capsule contraction syndrome, an infrequent but sight-compromising condition, can usually be managed by a neodymium:YAG (Nd:YAG) anterior capsulotomy. The anterior capsule can be split from the visual axis to the periphery with multiple spokes. In this patient, however, these spokes closed, leaving the small anterior capsulotomy indistinguishable from its pre-capsulotomy appearance. A subsequent Nd:YAG laser circumcision of the thickened capsulotomy margin restored the patient's sight. The excised capsular doughnut fell into the anterior chamber angle and resulted 34 months later in localized corneal decompensation. Removal of the capsular remnant markedly improved the corneal changes. The experience from this case suggests that multiple Nd:YAG relaxing incisions may be a safer way to manage capsule contraction syndrome than complete circumcision of the anterior capsule. If the latter approach is taken, the capsular remnant should not be cut completely free of the anterior capsule.

Anterior Chamber↗
PubMed1997

Chromic oxide inclusion in the diet does not affect glucose utilization or chromium retention by channel catfish, Ictalurus punctatus.

This study was conducted to determine if the level of dietary chromic oxide will affect glucose utilization and tissue chromium retention by channel catfish. Purified diets containing graded levels of supplemental chromic oxide (0, 50, 100, 200, 400, 1000, 5000 and 10,000 mg/kg diet) and glucose as the carbohydrate source were fed to channel catfish fingerlings for 10 wk. Another diet containing dextrin as the carbohydrate source and without chromic oxide supplementation was also fed and served as the control diet. Fish fed the dextrin diet had significantly (P < 0.05) greater weight gain, feed efficiency ratio and protein efficiency ratio but lower plasma glucose concentrations than fish fed the glucose diets irrespective of the level of chromic oxide supplementation. The growth performance and postprandial plasma glucose concentrations of channel catfish fed glucose diets supplemented with various chromic oxide levels were not significantly different. No obvious trends were observed in the whole-body composition of fish fed glucose diets containing various chromic oxide levels. Carbohydrate source or the level of dietary chromic oxide did not significantly affect chromium concentrations in the whole-fish carcass. These results suggest that the level of dietary chromic oxide had no significant effect on glucose utilization or chromium retention by channel catfish. It is suggested that chromic oxide is sufficiently inert to be used as an external marker in digestibility studies in channel catfish.

Animals↗
PubMed1997

A color Doppler analysis of nifedipine-induced posterior ocular blood flow changes in open-angle glaucoma.

PURPOSE: This pilot study used color Doppler imaging to investigate the effects of nifedipine on the posterior ocular blood flow of patients with glaucoma progression at normal intraocular pressures. PATIENTS AND METHODS: Eighteen patients, 11 men and seven women with a median age of 61.7 years, were imaged before and 6 weeks after the initiation of 30 mg of sustained-release nifedipine (Procardia XL; produced by either Pfizer or Pratt) daily. RESULTS: There was no statistically significant change in the blood velocity of the ophthalmic artery, central retinal artery, and main nasal and temporal short posterior ciliary arteries after treatment with nifedipine. CONCLUSION: The routine use of nifedipine in patients with normal tension glaucoma progression is not supported by this study.

Adult↗
PubMed1997

Encapsulated filtering blebs after trabeculectomy with mitomycin-C.

BACKGROUND AND OBJECTIVE: To determine the frequency of encapsulated blebs after guarded filtration procedures with mitomycin-C. PATIENTS AND METHODS: The authors reviewed the charts of all patients who had undergone a guarded filtration procedure with mitomycin-C. There were 235 patients (283 cases) who had more than 1 month of follow-up. RESULTS: An encapsulated bleb developed in 7 eyes (2.47%) of 6 patients. Identification of bleb encapsulation occurred at a mean follow-up time of 29.7 +/- 14.6 days after surgery. The mean intraocular pressure at that point was 24.2 +/- 13.5 mm Hg in the affected eyes. Three eyes were treated medically, and needling was performed in 4 eyes. CONCLUSION: There is a low frequency of encapsulated bleb formation after guarded filtration procedures with adjunctive mitomycin-C.

Administration, Topical↗
PubMed1997

Simultaneous use of mitomycin-C with Baerveldt implantation.

BACKGROUND AND OBJECTIVE: To evaluate the outcome of Baerveldt implantation with adjunctive mitomycin-C in cases of complicated glaucoma. PATIENTS AND METHODS: The authors reviewed the charts of all patients who had undergone Baerveldt implantation with mitomycin-C between January 1993 and March 1995. Success was defined before data collection as an intraocular pressure (IOP) between 5 and 21 mm Hg, with or without medications. The success rate was calculated using the Kaplan-Meier actuarial method. RESULTS: Twenty-nine patients were identified. The mean preoperative IOP was 33.6 mm Hg, with an average of 2.0 antiglaucoma medications. The probability of success at 6 and 12 months for patients who received mitomycin-C during Baerveldt implantation was 82.4% and 73.3%, respectively. Choroidal effusion with a flat anterior chamber (10.3%), corneal edema (6.8%), and conjunctival erosion (6.8%) were the most frequent complications. CONCLUSION: In this retrospective series of complicated glaucoma, the implantation of a Baerveldt drainage device with adjunctive mitomycin-C had a satisfactory outcome. The complications encountered and the clinical efficacy were comparable to those of previously reported series in which mitomycin-C was not used.

Antibiotics, Antineoplastic↗
PubMed1996

Influences of practice characteristics on prescribing in fundholding and non-fundholding general practices: an observational study.

OBJECTIVE: To investigate the variation in prescribing among general practices by examining the contribution to this variation of fundholding, training status, partnership status, and the level of deprivation in the practice population and to investigate the extent to which fundholding has been responsible for any changes in prescribing. DESIGN: Analysis of prescribing data (PACT) for the years 1990-1 (before fundholding) and 1993-4 (after fundholding), Use of multiple linear regressions to investigate the variation among practices in total prescribing costs (net ingredient cost per prescribing units), and mean cost per item in each of the two years and also the change in these variables between years. SETTING: Former Mersey region. SUBJECTS: 384 practices. RESULTS: The models developed explained the variation in cost per item (43% of variation explained for 1990-1, 38% for 1993-4) and prescribing volume (34% for 1990-1, 38% for 1993-4) better than the variation in total prescribing costs (3% for 1990-1, 7% for 1993-4). The models developed to explain the change in these variables between years did not explain more than 10% of the variation. Most of the explained variation in the change in total prescribing costs was accounted for by fundholding. Of the pounds 3.71 saved by first wave fundholders compared with non-fundholders pounds 3.57 was attributable to fundholding alone. CONCLUSION: In neither year did fundholding make a major contribution to the variation in prescribing behaviour among practices, which was better explained by deprivation, training status, and partnership status, but it did seem largely responsible for differences in the rise of total prescribing costs between fundholders and non fundholders.

Drug Prescriptions↗
PubMed1996

Body temperatures of free-living African penguins (Spheniscus demersus) and bank cormorants (Phalacrocorax neglectus).

Two free-living seabirds (the African penguin Spheniscus demersus and the bank cormorant Phalacrocorax neglectus) were equipped with stomach temperature-loggers to study body temperature changes during foraging. Body temperature in these endotherms was environmentally and activity-dependent and varied in the case of the cormorant by over 5 degrees C. Considerations of heat flux show that such flexibility confers considerable energetic advantages: by allowing body temperature to drop when the heat loss to the environment is high, such as in water, birds may save the energy that would normally be necessary to compensate for this drop. It appears that, in cormorants, low body temperature resulting from extended time in water can subsequently be elevated using solar energy when birds return to land in a manner similar to that of ectotherms. In the better-insulated penguins, muscle-generated heat during swimming is used to re-elevate low body temperature. Continued swimming eventually causes body temperature to rise above normal resting levels so that metabolic rate could theoretically be dramatically reduced immediately post-exercise when the temperature drops to some critical level before any increase in metabolism is necessary to correct it.

Animals↗
PubMed1996

Diving energetics in king penguins (Aptenodytes patagonicus).

Dive duration in wild king penguins and the energetic cost of swimming in a 30m long swim channel were determined at Ile de la Possession, Crozet Archipelago, using external data loggers and respirometry, respectively. Calibrated electronic data loggers equipped with a pressure sensor were used to determine dive durations: 95% of dives were less than 6 min long and 66% of dives were less than 4 min long. Dive patterns show that king penguins may intersperse long dive durations (4-6.3 min) with short ones (1.5-3 min) and make surface pauses of variable duration between them (0.5-3.5 min), or dive regularly (for up to 5 h) with long dive durations (5 min) and constant interdive surface intervals (1.5 min). The latter indicates that the aerobic dive limits (ADL) of this species could be higher and oxygen consumption lower than previously reported. Assuming that king penguins dive within their aerobic limit, different approaches to the analysis of the data obtained in the swim channel are discussed to derive the ADL. Swimming speeds observed in the channel ranged from 0.9 to 3.4 m s-1. Transport costs were lowest between 1.8 and 2.2 m s-1. Although at 2.2 m s-1 king penguins used only 10.3 Wkg-1 over a dive+surface cycle (minimal transport costs of 4.7 J kg-1 m-1), we speculate that tisse oxygen consumption during submergence may be as low as 0.23 ml O2 kg-1 s-1 (2.1 times standard metabolic rate, SMR) or perhaps lower (which gives an ADL of 4.2 min). During surface phases, oxygen uptake would be increased to at least 1 ml O2kg-1 s-1 (9.3 times SMR). This implies that at least 70% of all dives are aerobic. Potential physiological mechanisms allowing king penguins to partition O2 consumption between submergence and surface periods remain, however, unclear.

Animals↗
PubMed1996

Resuturing the scleral flap leads to resolution of hypotony maculopathy.

PURPOSE: We report four eyes of three glaucomatous patients who underwent trabeculectomy using topical mitomycin C. These eyes subsequently developed hypotony maculopathy. Snellen visual acuity decreased to 20/200 or worse in all cases. When the hypotony maculopathy persisted for 6-24 weeks and was unresponsive to nonsurgical therapies, we performed a second surgical procedure consisting of resuturing of the trabeculectomy scleral flap, closing the conjunctiva in its original position. METHODS: The limbal-based conjunctival flap was reopened and the original scleral trabeculectomy flap was located. This flap was resutured to surrounding sclera, presumably limiting filtration. RESULTS: This surgical revision increased the intraocular pressure, reversing the hypotony, and resulted in improved visual acuity to 20/25 or better in all cases with intraocular pressures between 6 and 17 mm Hg without intraocular pressure-lowering medications. The minimum follow-up after revision is 18 months. CONCLUSION: There seems to be a definite relationship between the elevation of intraocular pressure and reversal of the macular damage associated with hypotony maculopathy. The visual outcome we experienced following resuturing of the scleral flap after persistent hypotony appears excellent in the treatment of a complication that is difficult to reverse. This technique has potential and should be strongly considered as a possible therapy in the management of hypotony maculopathy.

Adult↗
PubMed1996

Management of coexisting corneal disease and glaucoma by combined penetrating keratoplasty and trabeculectomy with mitomycin-C.

BACKGROUND AND OBJECTIVE: The management of coexistent corneal disease and uncontrolled glaucoma continues to be a challenging clinical situation. The purpose of this study is to evaluate the results of combined penetrating keratoplasty and trabeculectomy with mitomycin-C. PATIENTS AND METHODS: A retrospective study was undertaken to review the records of nine patients who had corneal edema and high intraocular pressure managed by simultaneous penetrating keratoplasty and trabeculectomy with mitomycin-C. RESULTS: The nine patients had an average pre-operative intraocular pressure of 26 mm Hg (range 17 to 41 mm Hg) and associated corneal edema. The average postoperative intraocular pressure at last follow-up was 19 mm Hg (range 5 to 53 mm Hg). Three patients needed additional procedures. Six of nine patients had intraocular pressures judged to be adequately controlled (11 +/- 5 mm Hg, range 5 to 18 mm Hg) throughout the postoperative period (average follow-up 16 months). Grafts remained clear in seven patients. The grafts failed in two cases in which additional glaucoma surgery was necessary. CONCLUSION: Combined penetrating keratoplasty and trabeculectomy with mitomycin-C should be considered for selected patients with uncontrolled glaucoma and corneal disease who have sufficient conjunctiva for a filtering procedure.

Aged↗
PubMed1995

Alterations in prescribing by general practitioner fundholders: an observational study.

OBJECTIVES: To compare prescribing in general practices before and after they become fundholders to assess whether this affected prescribing patterns. DESIGN: Analysis of prescribing data (PACT) for one year before and one year after practices become first, second, or third wave fundholders and comparison with practices that were not fundholders during any part of the study. MAIN OUTCOME MEASURES: Prescribing costs (net ingredient cost per prescribing unit), prescribing volume (items per 1000 prescribing units), net ingredient cost per item, and percentage of generic prescribing. SETTING: Former Mersey Regional Health Authority. SUBJECTS: 100 fundholders (20 first wave, 31 second wave, 49 third wave) and 312 nonfundholders. RESULTS: Prescribing costs and volume rose throughout the study in all groups. In all three fundholding waves the rate of increase of prescribing costs was significantly lower than for nonfundholders. Both cost per item and prescribing volume tended to decrease, the former probably because of a significant increase in generic prescribing. Fundholding and non-fundholding practices differed in several respects. CONCLUSION: Fundholding has altered practice prescribing patterns compared with those of nonfundholders, increasing generic prescribing and reducing the rate of increase of prescribing costs.

Drug Costs↗