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Biomedical subjects

J Clarkson

Publications and source records attributed to J Clarkson.

At least 55 records · Page 3Linked to original sources
PubMed1991

Introducing healthy catering practice into hospitals: a case study from Wales.

This paper describes results from a study examining the introduction of policies to promote healthy catering in 102 hospitals in Wales. Policy development and implementation followed the publication of two major reports in the UK highlighting the relationship between poor nutrition and subsequent high levels of cardiovascular disease and cancer. Changes in hospital catering services were advocated in response to these reports. The study examines the translation of policy intentions into practical action in hospitals. It identifies achievements in implementing changes in catering practice, and promotion of healthier meals for staff, patients and visitors to hospitals. Important organisational problems and external constraints, including cost, are also highlighted. The authors recommend that greater effort is put into the implementation process following policy decisions, including consideration of training needs, the development of effective communication, and establishment of mechanisms for feedback and review.

Food Service, Hospital↗
PubMed1989

Crystallization and X-ray data collection on human growth hormone.

Single crystals of natural sequence human growth hormone have been grown from media containing ethanol, acetone or paraldehyde. Recombinant growth hormone in its native and desamidated form and pituitary hormone have been crystallized. A full native set of diffraction data extending to 3.5 A resolution has been obtained with synchrotron radiation for crystals of recombinant human growth hormone grown from ethanol. The identity of the material in these crystals has been established by anion-exchange chromatography.

Chromatography, Ion Exchange↗
PubMed1989

A modified DDE Index for use in epidemiological studies of enamel defects.

The aim of this study was to investigate possible modifications to the DDE Index to make it simpler to use and to make the data collected more meaningful and amenable to analyses and interpretation. After the use of the DDE Index in a National Study in Ireland, initial alterations to the Index were tested on a group of children with enamel defects, in Ireland and New Zealand. The DDE Index was then modified to allow for the measurement of demarcated, diffuse, and hypoplastic defects and their severity. With the Modified Index, the prevalence of defects both on index teeth and all permanent tooth surfaces of 8- and 15-year-old children in fluoridated Cork City and non-fluoridated areas of Cork County and Manchester, U.K., was measured. The prevalence of enamel defects on one or more index teeth of children in the three areas ranged from 30 to 42% in 8-year-olds and from 31 to 38% in 15-year-olds. The percentage of children affected as seen by full-mouth examination was somewhat higher, ranging from 38 to 51% for 8-year-olds and 58 to 63% for 15-year-olds. The percentage of index teeth affected (7 to 14%) was generally higher than for all teeth (5 to 9%). Demarcated opacities were the most common defect seen. Diffuse opacities were found to be the discriminating factor between the fluoridated and non-fluoridated areas. In all areas, the vast majority of diffuse opacities extended over less than 1/3 of the surface area of the teeth affected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Review of terminology, classifications, and indices of developmental defects of enamel.

A wide variety of terms and definitions are used to describe various developmental defects of enamel. Some are simple descriptive clinical terms, and others are linked with the causative agent or the histopathology of the defect. Some confusion exists as to the most appropriate type of index to use to measure defects of enamel due to fluoride ingestion (dental fluorosis). This is primarily due to difficulties some researchers have in distinguishing between defects of fluoride and non-fluoride origin. This problem has resulted in the development of specific fluorosis indices and purely descriptive indices. The main fluorosis indices are those of Dean, Thylstrup and Fejerskov, and the TSIF Index. Dean's Index does not provide adequate information on the distribution of fluorosis within the dentition and is not sensitive at high fluorosis levels. The Thylstrup and Fejerskov Index is related to the histology of florosis; however, the initial minute changes observed on dry enamel surfaces are of little esthetic importance. The TSIF Index does overcome some of the limitations of Dean's Index. The DDE Index has replaced the Al-Alousi Index as the main descriptive index. The DDE Index is time-consuming, and the analyses of data are complicated. Modifications have now been proposed to make it simpler to use and the data more meaningful. Further research needs to be carried out into both the validity of the fluorosis indices and making the DDE Index more universally acceptable.

Dental Enamel↗
PubMed1989

Visual results and complications after retinal reattachment in the acute retinal necrosis syndrome. The influence of operative technique.

The authors compare the complications and visual results encountered in a consecutive series of 16 eyes undergoing retinal reattachment surgery for retinal detachment associated with the acute retinal necrosis syndrome. Eight eyes were treated with scleral buckling, vitrectomy, and cryotherapy with or without gas injection. Eight consecutive eyes (with one exception) were treated by the combination of vitrectomy, gas injection and laser photocoagulation with or without primary lensectomy and not subjected to scleral buckling as a primary procedure. The final reattachment rate was 93.8% (15 of 16 eyes) with no significant difference between the primary scleral buckle group (87.5%) and the non-buckle group (100%). Retinal reoperation and complication rates were higher in the primary buckle group and final visual acuities better in the non-buckle group despite comparable preoperative characteristics.

Adolescent↗
PubMed1989

The effectiveness of two test dentifrices on dental plaque formation: a 1-week clinical study.

A 1-week, double-blind clinical study was conducted to compare the effects on plaque formation of two test dentifrices with a placebo dentifrice. Male and female adult subjects received an oral prophylaxis and were randomly allocated to three study groups. The subjects used the dentifrice three times daily and were examined for the presence of plaque after seven days. The results indicated that one of the two test dentifrices, containing 0.3% triclosan, 2% of a copolymer, and 0.76% sodium monofluorophosphate in an insoluble sodium metaphosphate abrasive system, significantly reduced plaque formation by 16% when compared to the placebo dentifrice.

Adult↗
PubMed1988

Vitrectomy for retinal detachment associated with acute retinal necrosis.

Six patients with retinal detachment associated with the acute retinal necrosis syndrome were treated by the combination of vitrectomy, gas injection, and laser photocoagulation. The retinas were successfully reattached in each patient with one operation. Five of the patients achieved a visual acuity of 20/200 or better, and three had a visual acuity of 20/40 or better.

Adolescent↗
PubMed1987

Pars plana vitrectomy for vitreous amyloidosis.

Thirty-six pars plana vitrectomies were performed on 30 eyes of 17 patients with biopsy-proven vitreous amyloidosis. Reopacification of the retrolental vitreous was the most common reason for vitrectomy revision, required in 24% of patients. Complications of amyloid or vitrectomy included retinal detachment requiring scleral buckling in 17% of eyes and glaucoma requiring filtering surgery in 17% of eyes. After a mean 35-month post-vitrectomy follow-up, 48% of eyes had visual acuities of 20/40 or better, and 32% of eyes had visual acuities between 20/50 and 20/100. Twenty percent of eyes had visual acuities of 20/200 or worse due either to persistent retinal detachment, open angle glaucoma, or residual opacification of the vitreous.

Amyloidosis↗
PubMed1986

Mechanism-based fragmentation of coenzyme A transferase. Comparison of alpha 2-macroglobulin and coenzyme A transferase thiol ester reactions.

The plasma proteins, alpha 2-macroglobulin and complement components 3 and 4, contain an internal thiol ester involving a glutamyl and cysteinyl residue. The thiol ester is susceptible to cyclization at greater than 37 degrees C and forms an unstable 5-oxyproline intermediate. The latter can be hydrolyzed to produce two peptide fragments. We propose that enzymes having activated glutamyl residues as part of their catalytic mechanisms may undergo an analogous cyclization and peptidyl cleavage. As a model, we have investigated pig heart succinyl-CoA:3-keto acid transferase. When the CoA-enzyme thiolester intermediate is heated at pH 7.4 and 70 degrees C for 1 h, approximately 60% of the Mr = 60,000 subunits are cleaved to give Mr = 40,000 and 20,000 fragments. We have shown that formation of the enzyme thiolester is an obligate precursor for the protein fragmentation. However, the reaction was incomplete with a maximum of approximately 65% cleavage at times greater than 60 min. These results suggest that there is a competing, deactivation reaction; namely, the thiol ester and oxyproline intermediates are hydrolyzed to regenerate the active site glutamic acid. Although the maximum rate of cleavage is at 70 degrees C, approximately 15% autolysis also occurs at 37 degrees C. The Mr = 40,000 fragment had the same amino terminal sequence as the Mr = 60,000 subunit, (Trp-Lys-Phe-Tyr-Thr-Asp-Ala-Val-Glu-Ala-). No amino terminal could be detected for the Mr = 20,000 fragment, even after digesting the fragment with pyroglutaminase. Peptide maps of the fragments and the uncleaved subunit indicate that the fragments are generated in parallel. The size of the fragments puts the active site about two-thirds of the way from the amino terminal of the protein.

Acyltransferases↗
PubMed1986

The relative cytotoxicity and mutagenicity of cyclobutane pyrimidine dimers and (6-4) photoproducts in Escherichia coli cells.

In order to calculate the relative cytotoxicity and mutagenicity of (5-6) cyclobutane pyrimidine dimers and (6-4) photoproducts, we have measured survival and mutation induction in UV-irradiated excision-deficient E. coli uvrA cells, with or without complete photoreactivation of the (5-6) dimers. Radioimmunoassays with specificity for (5-6) dimers or (6-4) photoproducts have shown that maximum photoreactivation eliminates all of the (5-6) dimers produced up to 10 Jm-2 254-nm light, while it has no effect on (6-4) photoproducts. These results were confirmed by measuring the frequency of T4 endonuclease V-sensitive sites. Based on the best fit equations for survival and mutation induction, we have found that the calculated cytotoxicity of (6-4) photoproducts is similar to that of (5-6) dimers; however, the former is much more mutagenic than the latter.

Dose-Response Relationship, Radiation↗
PubMed1984

Schistosoma mansoni: an in vivo study of drug-induced autophagy in the gastrodermis.

The effects of Astiban, Lucanthone, Hycanthone and Niridazole on autophagic activities in the gastrodermis of Schistosoma mansoni were determined in vivo, using different dosage levels and dosage times. With Astiban, high levels of autophagy were observed in the gastrodermis 2 hours after an injection of the drug into the mouse, and this response had declined by 20 hours, marking a recovery by the parasite from the drug. Hycanthone and Lucanthone produced an autophagic response several days after the onset of treatment, and no recovery was observed in the morphology of the gastrodermis after the drug was discontinued. The effects of Niridazole on the gastrodermis were to produce the most dramatic ultrastructural changes after high doses and over several days of treatment. With all the drugs examined, gastrodermal autophagy was characterized by the formation of vacuoles containing cell components, lipid droplets and sometimes hydrolytic enzyme reaction product. The autophagic vacuoles appeared to be formed by the sequestration of cytoplasmic material by the basal membrane infoldings, and the transfer of enzymes into the vacuole from within the limiting membrane. The residues from intracellular digestion appeared to be emptied into the caecal lumen.

Animals↗
PubMed1982

Branch vein occlusion. Retinal neovascularization outside the involved segment.

Three hundred sixty-six cases of branch vein occlusion entered within the multicenter Branch Vein Occlusion Randomized Clinical Trial have been reviewed. Four cases that developed retinal neovascularization outside of the retinal area involved with the occlusion have been documented by photography and fluorescein angiography.

Aged↗
PubMedDate not supplied

Increasing the reach of health sponsorship: using a "sponsorship kit" to promote health.

In Australia, a tobacco tax provides funding for Healthway, the Western Australian Health Promotion Foundation. Healthway provides sponsorships for the arts and racing and sporting events to replace funds previously provided by tobacco companies. These sponsorships provide visibility for Healthway and positive health messages. Normally, Healthway staff attends these events to help promote health messages. To reduce Healthway staff time spent helping event organizers promote health messages, Healthway developed a sponsor kit of promotional materials which communicate health messages without requiring Healthway staff to attend events. Recognition, awareness, comprehension, and acceptance of health messages was comparable at events that featured Healthway staff versus the sponsor kits, but the average cost of the sponsorship kits was only 40% of the cost when Healthway staff was featured.

Advertising↗