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Biomedical subjects

R M Jones

Publications and source records attributed to R M Jones.

At least 361 records · Page 20Linked to original sources
PubMedDate not supplied

Laparoscopic cholecystectomy for complicated gallstone disease.

After performing selectively 25 laparoscopic cholecystectomies (LC) to determine the place of LC in the management of complicated gallstones, all patients presenting with gallstones were evaluated by the authors for LC. Eighty-six consecutive patients were evaluated and 84 were studied. Follow-up in every case exceeded 6 months. In three of 10 patients with acute cholecystitis, LC was not possible; each had a history longer than 48 h and all had gangrene of the gallbladder. In four patients with empyema, LC was successful, but operative cholangiography failed. Operative cholangiography was successful in 76 of the remaining 77. Of eight patients suspected of having stones in the CBD, cholangiography excluded stones in six and confirmed them in two. Cholangiography identified three other patients with totally unsuspected CBD stones. Of the five patients with CBD stones, four had them flushed to the duodenum at LC following transcystic balloon dilatation of the papilla and one had a post-op. ERCP. Of four patients with acute pancreatitis, three had LC in the same admission. LC was possible in all three patients with morbid obesity. We conclude that with experience, LC is possible for complicated gallstones. In acute cholecystitis, the probability of success is higher with earlier operative intervention. Operative cholangiography is essential. It not only identifies unsuspected CBD stones but also allows LC without ERCP in those with suspected CBD stones and with modification it allows treatment of those stones.

Acute Disease↗
PubMedDate not supplied

Laparoscopic cholecystjejunostomy as palliation for obstructive jaundice in inoperable carcinoma of pancreas.

Malignant obstructive jaundice can be palliated by either surgical bypass, which has the advantage of long-term patency, or by stent placement, which has the advantage of initial lower morbidity and mortality. We describe a technique, laparoscopic cholecystjejunostomy, which has the advantage of both. We predict that laparoscopic surgery, which has already had a major impact on biliary stone surgery, will also have a major impact on interventional endoscopic retrograde cholangiopancreatography.

Cholecystostomy↗
PubMedDate not supplied

Pathology of radiation-induced coronary artery disease in human and pig.

PURPOSE: External beam mediastinal radiation-induced accelerated coronary atherosclerotic heart disease in humans has been recognized, especially when the condition occurs in young persons. The purpose of the present study was to compare external beam radiation-induced accelerated coronary atherosclerosis in humans with that seen in the pig coronary arteries following radioactive stent placement. METHODS: A literature review of radiation-induced coronary artery disease was performed. In addition, clinical records and coronary histology from the Armed Forces Institute of Pathology Registry were reviewed from patients who had received external beam radiation for mediastinal malignancies. Coronary arteries from pigs that had radioactive coronary stent placement were evaluated from our stent pathology laboratory and analyzed for comparison with the human disease. RESULTS: In humans, the characteristics of the intimal plaque in accelerated atherosclerosis postradiation therapy were similar to that seen in typical atherosclerotic coronary disease in the absence of radiation therapy. However, medial thinning and adventitial fibrosis were the distinguishing pathologic arterial changes secondary to radiation seen in humans. Radioactive stent placement in pig coronary arteries produced similar changes to that observed in humans post-external beam radiation, consisting of medial injury and adventitial thickening accompanied by intimal foam cell collections, calcification, and necrotic core formation containing cholesterol clefts resulting in severe luminal narrowing. CONCLUSIONS: Radiation, delivered via external beam or radioactive stent, induces changes of intimal atherosclerosis with medial thinning and adventitial scarring in human and pig. Therefore, pending completion of long-term clinical studies, caution should be exercised before the widespread use of brachytherapy is advocated for the treatment and prevention of coronary restenosis.

Animals↗
PubMedDate not supplied

Preparation of well-defined protein conjugates using enzyme-assisted reverse proteolysis.

A two-step approach to the production of well-defined protein conjugates is described. In the first step, a linker group, carbohydrazide, having unique reactivity (a hydrazide group) is attached specifically to the carboxyl terminus by using enzyme-catalyzed reverse proteolysis. Since the hydrazide group exists nowhere else on the protein, specificity is assured in a subsequent chemical reaction (formation of a hydrazone bond) of the modified protein with a molecule (chelator, drug, or polypeptide) carrying an aldehyde or keto group. The product is sufficiently stable at neutral pH, no reduction of the hydrazone bond being necessary for the hydrazones described. Protein modification is thus restricted to the carboxyl terminus and a homogeneous product results. With insulin as a model, conditions are described for producing such well-defined conjugates in good yields. The use of other linker groups besides carbohydrazide, and applications of these techniques to antibody fragments, are discussed.

Chemistry, Organic↗
PubMedDate not supplied

Nutrient movement and removal in a switchgrass biomass-filter strip system treated with dairy manure.

Manure use on cropland has raised concern about nutrient contamination of surface and ground waters. Warm-season perennial grasses may be useful in filter strips to trap manure nutrients and as biomass feedstock for nutrient removal. We explored the use of 'Alamo' switchgrass (Panicum virgatum L.) in a biomass production-filter strip system treated with dairy manure. We measured changes in extractable P in the soil, NO3 -N in soil water, and changes in total reactive P and chemical oxygen demand (COD) of runoff water before and after a switchgrass filter strip. Five rates of dairy manure (target rates of 0, 50, 100, 150, and 200 kg N ha(-1) from solid manure in 1995; 0, 75, 150, 300, and 600 kg N ha(-1) from lagoon effluent in 1996 and 1997) were surface-applied to field plots of switchgrass (5.2 by 16.4 m) with a 5.2- by 16.4-m switchgrass filter strip below the manured area. Yield of switchgrass from the manured area increased linearly with increasing manure rate in each year. Soil water samples collected at 46 or 91 cm below the soil surface on 30 dates indicated < 3 mg L(-1) of NO3-N in all plots. Concentrations of total reactive P in surface runoff water were reduced an average of 47% for the 150 kg N rate and 76% for the 600 kg N rate in 1996 and 1997 after passing through the strip. Manure could effectively substitute for inorganic fertilizer in switchgrass biomass production with dual use of the switchgrass as a vegetative filter strip.

Animals↗
PubMedDate not supplied

Relationship of soil test phosphorus and sampling depth to runoff phosphorus in calcareous and noncalcareous soils.

A study was initiated to investigate the relationship between soil test P and depth of soil sampling with runoff losses of dissolved molybdate reactive phosphorus (DMRP). Rainfall simulations were conducted on two noncalcareous soils, a Windthorst sandy loam (fine, mixed, thermic Udic Paleustalf) and a Blanket clay loam (fine, mixed, thermic Pachic Argiustoll), and two calcareous soils, a Purves clay (clayey, smectitic, thermic Lithic Calciustoll) and a Houston Black clay (fine, smectitic, thermic Udic Haplustert). Soil (0- to 2.5-, 0- to 5-, and 0- to 15-cm depths) and runoff samples were collected from each of the four soils in permanent pasture exhibiting a wide range in soil test P levels (as determined by Mehlich III and distilled water extraction) due to prior manure applications. Simulated rain was used to produce runoff, which was collected for 30 min. Good regression equations were derived relating soil test P level to runoff DMRP for all four soil types, as indicated by relatively high r2 values (0.715 to 0.961, 0- to 5-cm depth). Differences were observed for the depth of sampling, with the most consistent results observed with the 0- to 5-cm sampling depth. Runoff DMRP losses as a function of the concentration of P in soil were lower in calcareous soils (maximum of 0.74 mg L(-1)) compared with noncalcareous soils (maximum of 1.73 mg L(-1)). The results indicate that a soil test for environmental P could be developed, but it would require establishing different soil test P level criteria for different soils or classes of soils.

Calcium↗
PubMedDate not supplied

Preparing health educators for the workplace: a university-health insurance company alliance.

The workplace is a relatively recent and an increasingly recognized setting for health education. In this article, philosophical and economic reasons for this movement of health education in the workplace are cited. Currently the workplace is one of the fastest growing markets for health education. In most institutions, preparing health educators for the workplace has not been adequately addressed. Consequently, an experimental course entitled "Health Promotion and Educational Strategies for the Workplace" was developed and taught at The Ohio State University in the summer of 1981. Besides an extensive reading list and lively class discussions, the course was team-taught primarily by a health education faculty member and a health insurance program manager/health educator.

Health Education↗
PubMedDate not supplied

Comparative pathology: radiation-induced coronary artery disease in man and animals.

The occurrence of coronary artery disease following mediastinal radiation for malignancies has long been debated. However, the development of coronary pathology in young individuals following radiation who lack risk factors for atherosclerosis is highly suggestive of a cause-and-effect relationship. By far the most convincing pathologic changes are adventitial scarring and medial atrophy with severe intimal atherosclerotic disease consisting of necrotic core, fibrous tissue, and calcification. Initial clinical studies in patients with coronary atherosclerosis treated with intraluminal radiation following stenting hold great promise in the treatment and prevention of restenosis. There are little or no data, however, on long-term effects of intra-coronary radiation therapy in man. Therefore, it may be important to study the chronic effects of radiation in animal models in order to predict what is likely to occur in humans. We evaluated the effects of varying doses (0.15-23.0 microCi of 32P) of beta-particle-emitting radioactive stents in pig coronary arteries at 1 and 6 months. At 1 month, there were dose-dependent changes in the morphology of the intima and media. High activities (>3 microCi) caused medial necrosis with fibrin deposition in the media and intima, with interspersed red cells most marked in regions surrounding the stent struts. Only rare smooth muscle cells (SMCs) and inflammatory cells were seen away from the stent struts. In the intermediate (1 microCi) stent activity group, the neointima was expanded by SMCs and a proteoglycan-rich matrix with focal endothelialization of the luminal surface. Neovascular capillaries and extravascular red cells were present adjacent to stent struts. At low activities (<0.5 microCi), the neointima was significantly smaller than control stents and consisted of SMCs and matrix with complete endothelialization of the luminal surface. The neointimal cell density of the media and intima decreased with increasing doses of radiation. In pigs 6 months after radioactive stenting (activities ranging from 0.5-12 microCi 32P), >3.0 microCi radioactive stents induced marked neointimal thickening, with changes similar to atherosclerosis, consisting of necrotic debris containing cholesterol clefts surrounded by macrophage collections, fibrosis, and focal calcification. There was increased adventitial thickening in the radiated vs non-radiated arteries. The intermediate stent activity (1.0 microCi) also showed greater neointimal thickening (vs control stents) and consisted mostly of SMCs in a proteoglycan-rich matrix. At <1.0 microCi, there were minimal differences seen between radiated and control non-radiated stented arteries. The media was unevenly injured in all stent activities and varied from less than to significantly greater than controls. These data suggest that radiation-induced coronary atherosclerosis seen in man is partially simulated in normal porcine coronary arteries 6 months following high-dose beta-particle-emitting radioactive stent placement. There is greater fibrosis and thickness of the adventitia and focal attenuation of the media in man and severe luminal narrowing in pig coronary arteries treated with high doses of radiation. Only long-term clinical follow up and careful autopsy studies will determine if endoluminal or intra-arterial radiation is a viable means of reducing restenosis in man.

Animals↗
PubMedDate not supplied

Inhaled anaesthetic agents: from halothane to the present day.

Despite the enormous resources spent on research and development, only two new volatile agents have been introduced into anaesthetic practice in the UK since the introduction of halothane. This article reviews their properties and looks towards changes in volatile anaesthetic availability in the near future.

Anesthesia, Inhalation↗
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Dentin exposure and decay incidence when removable partial denture rest seats are prepared in tooth structure.

Prosthodontists surveyed preferred inverted V-shaped canine cingulum ledge rest seats located at the junction of the middle and cervical thirds of the lingual surface. Most respondents indicated that they preferred a ledge depth of at least 1.0 mm and indicated that their preparations usually did not extend into dentin. When the respondents evaluated various ledge depths, the mean depth of those judged adequate was 0.74 mm, which was less than the respondent and textbook recommendations. Premolar occlusal rest seats judged adequate generally met textbook size guidelines. The mean clinical incidence of dentin exposure with cingulum ledges and occlusal rest seats was 61%, close to the 55% exposure rate found on extracted teeth. Dentin Detector Gel effectively identified clinical dentin exposure but tooth sensitivity was not a good indicator of dentin exposure. Seventy-one of the 107 rest seats studied for incidence of caries and decalcification had exposed dentin but only two of the 71 had lesions. Ten of the 107 had small enamel fractures, primarily occurring on cingulum ledges.

Attitude of Health Personnel↗
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Inhaled anaesthetic agents: from ether to halothane.

The introduction of general anaesthesia revolutionized surgical practice. In this workshop and the one that follows in a future issue the evolution and properties of inhalational anaesthetics are reviewed and future developments are considered. Here we look at the period between the introduction of ether and of the first modern agent, halothane.

Anesthesia, Inhalation↗
PubMedDate not supplied

Hydrophilic poly(vinyl siloxane) impression materials: dimensional accuracy, wettability, and effect on gypsum hardness.

Three hydrophilic poly(vinyl siloxane) impression materials, containing an intrinsic surfactant, were compared with a hydrophobic poly(vinyl siloxane) and a polyether impression material. The hydrophobic poly(vinyl siloxane) material was dimensionally more accurate than the hydrophilic poly(vinyl siloxane) in two of three measured dimensions, but the difference was small. The polyether material was the most wettable, and the hydrophilic poly(vinyl siloxane) were more wettable than the hydrophobic poly(vinyl siloxane). However, when a topical surfactant was used, no difference in wettability was noted between the hydrophilic and hydrophobic poly(vinyl siloxane), and their wettability was comparable to the polyether material, indicating that the topical surfactant was more effective than the intrinsic surfactants. Stone dies made from the hydrophobic poly(vinyl siloxane) material were harder than those obtained from the other materials.

Analysis of Variance↗
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Studies on the anthelmintic effect of a sustained release pre-grazing treatment with morantel in grazing cattle in Sweden.

The effect of a morantel sustained release bolus (MSRB) to control gastrointestinal parasitism in cattle grazing their first season was assessed under field conditions in Sweden. The MSRB was administered orally to calves immediately prior to turnout onto spring pastures in May 1978. The level of pasture contamination of infective larvae was decreased by 73 per cent in August and by 98 per cent in September. There was a 72 per cent reduction in worm burdens acquired over the entire grazing season. During the same period the mean improvement in weight gain was 21.5 kg per animal. Weight gains were also recorded during housing until slaughter in April 1979, i.e. 335 days after MRSB administration at which time the treated animals were on an average 17.1 kg heavier than controls.

Animals↗
PubMedDate not supplied

Further studies on the anthelmintic effect of a sustained release pre-grazing treatment with morantel in grazing cattle in Sweden.

The efficacy of a morantel sustained release bolus (MSRB) to control gastrointestinal parasitism in first season grazing cattle was assessed under field conditions in Sweden. The MSRB was administered orally to calves immediately prior to turnout onto spring pastures in May, 1979, or in mid-season (July). The level of pasture contamination with infective larvae was reduced by 99 per cent in September by treatment at turnout. The corresponding figure was 89 per cent when the MSRB was administered in July. There was a 95 per cent reduction in worm burdens acquired over the entire grazing season in cattle treated in the early season and a 44 per cent reduction in worm burdens of cattle treated in the mid-season. During the 132 days grazing period a 19.1 kg (p less than 0.01) mean weight gain advantage was achieved by the early season treated animals, while a 10.0 kg mean weight gain advantage was achieved by the mid-season treatment. The weight gain advantage at the end of the grazing season in the early treated cattle increased continually during the winter with a resultant mean difference of 44.4 kg (p less than 0.01) by April 1980. Over the same period the mean weight gain advantage of the mid-season treated animals gradually fell to a final of 5.5 kg.

Animals↗