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Biomedical subjects

P L Wright

Publications and source records attributed to P L Wright.

At least 19 recordsLinked to original sources
PubMed1988

Angiographic cystoid macular edema after posterior chamber lens implantation.

We performed a prospective study evaluating the incidence of angiographic cystoid macular edema (CME) following extracapsular cataract extraction and posterior chamber intraocular lens implantation. Of the 162 eyes in the study, 141 were randomized into either a primary capsulotomy or a capsule intact group. The remaining eyes were not randomized due to intraoperative surgical complications, but they were included in the follow-up studies. Six weeks after surgery, angiographic CME was documented in 24% of the capsulotomy group and in 16% of the capsule intact group. The differences were not statistically significant. Including nonrandomized cases reduced the overall incidence of angiographic CME and the difference between the two groups. Angiographic CME was usually not extensive, and it was associated with a visual acuity less than 20/40 in 2.5% of eyes six weeks postoperatively. A subgroup of 120 eyes was followed up for approximately six months, when angiographic CME was present in 4% of the capsulotomy and capsule intact groups.

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PubMed1986

The long case.

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PubMed1983

Hepatic sinusoidal endothelium in sheep: an ultrastructural reinvestigation.

Following perfusion fixation of livers from fetal, neonatal, and adult sheep, the ultrastructure of the fenestrated sinusoidal endothelium was examined. In contrast to an earlier report which utilized immersion fixation, we found the fenestrae to be unoccluded by diaphragms or basal lamina, thus offering only a discontinuous barrier between the blood and the space of Disse and hepatocytes. This observation was confirmed by perfusing the liver with marker particles. The fenestrae appear, therefore, to have a sieving function, regulating the metabolism of particulate matter such as lipoproteins in sheep in a similar manner to that which has been shown to occur in rats.

Animals↗
PubMed1983

Hepatic sinusoidal endothelium in goats.

The ultrastructure of the hepatic sinusoids of the goat was examined. Contrary to current belief concerning this and other ruminant species, we found the sinusoids to be lined by a smooth, continuous layer of endothelium, broken only by the presence of numerous, unoccluded fenestrae which provide a direct path of communication between the sinusoidal lumen and the space of Disse. Therefore, we suggest that a sieving function similar to that which has been shown to occur in rats may be attributed to the sinusoidal endothelium of the goat.

Animals↗
PubMed1976

Toxicity of combustion products from burning polymers: development and evaluation of methods.

Laboratory and room-scale experiments were conducted with natural and synthetic polymers: cotton, paper, wood, wool, acetate, acrylic, nylon, and urethane. Smoke and off-gases from single materials were generated in a dual-compartment 110-liter exposure chamber. Multicomponent, composite fuel loads were burned within a 100 m(3) facility subdivided into rooms. In chamber experiments, mortality depended on the amount of material burned, i.e., fuel consumption (FC). Conventional dose (FC)/mortality curves were obtained, and the amount of fuel required to produce 50% mortality (FC(50)) was calculated. With simple flame ignition, cotton was the only material that produced smoke concentrations lethal to rats; FC(50) values for cotton ranged from 2 g to 9 g, depending on the configuration of the cotton sample burned. When supplemental conductive heat was added to flame ignition, the following FC(50) values were obtained; nylon, 7 g; acrylic, 8 g; newsprint, 9 g; cotton, 10 g; and wood, 11 g. Mortality resulting from any given material depended upon the specific conditions employed for its thermal decomposition. Toxicity of off-gasses from pyrolysis of phosphorus-containing trimethylol propane-polyurethane foams was markedly decreased by addition of a flame ignition source. Further studies are needed to determine the possible relevance of single-material laboratory scale smoke toxicity experiments. Room-scale burns were conducted to assess the relative contributions of single materials to toxicity of smoke produced by a multicomponent self-perpetuating fire. Preliminary results suggest that this approach permits a realistic evaluation of the contribution of single materials to the toxicity of smoke from residential fires.

Animals↗
PubMed1976

An evaluation of the L-methionine activity of the hydroxy analogue of methionine.

Three product forms of methionine hydroxy analogue were prepared for biological evaluation of their L-methionine activity for broiler strain chickens (Vantress x Arbor Acres). Two samples of the acid of the analogue HA-50, LMA-70 and one sample of a commercial grade (90%) MHA were standarized by gas liquid chromatography to contain a known amount of L-methionine activity as the free analogue acid. Each product form was tested in a separate experiment. The experimental chickens were fed a practical corn-soybean meal basal diet for the first seven days of the test. A semi-purified diet composed primarily of cerelose, isolated soybean protein and soybean meal was used for the remainder of the experimental period. HA-50 and the commercial form of the hydroxy analogue were formulated to contain 50% L-methionine activity. Hence, they were added to the diets at 0.1 and 0.2% and compared to the L-methionine standard which was added to levels of 0.05, 0.1 and 0.15%. LMA-70 was formulated to contain 70% L-methionine activity and was added to the experimental diets at 0.07 and 0.14% and compared to the L-methionine standard at the same levels used in the other experiments. Statistical analysis of four-week data revealed no difference between the biological response of L-methionine and the three forms of the analogue when tested at comparable L-methionine activity levels. The biological of the analogue products was in good agreement with the L-methionine activity determined by gas liquid chromatography.

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