Biomedical subjects

V G Allen

Publications and source records attributed to V G Allen.

36 records · Page 2Linked to original sources

PubMed1994

Digestibility, nitrogen utilization, and voluntary intake of ensiled crab waste-wheat straw mixtures fed to sheep.

Crab waste and wheat (Triticum aestivum L.) straw mixtures, ensiled with different additives, were evaluated in metabolism and palatability trials. Crab waste and straw were mixed in proportions of 1:1, wet basis, with 20% water and different additives, and ensiled in 210-L metal drums double-lined with polyethylene bags. Thirty crossbred wethers (40 kg initial BW) were fed a 1) basal diet consisting of 75% orchardgrass (Dactylis glomerata L.) hay and 25% concentrate, 2) ensiled crab waste-wheat straw, with 16% (vol/wt) added glacial acetic acid, 3) crab waste-wheat straw ensiled with 20% dry molasses, 4) crab waste-wheat straw ensiled with 20% dry molasses and a microbial inoculant, and 5) ensiled wheat straw supplemented with urea. Apparent digestibility of DM and CP was lower (P < .05) for acetic acid-treated silages than for silages containing molasses. Nitrogen retention was higher (P < .05) for molasses-inoculant-treated silage than for the molasses-treated silage (5.4 vs 3.9 g/d). Ruminal NH3 N and blood urea N were higher (P < .05) for lambs fed the molasses-treated silages than for those receiving the acetic acid-treated crab waste mixture. Among the wethers fed crab waste silages, intake was lower (P < .01) for wethers receiving the acetic acid-treated silage than for those fed the molasses-treated mixtures. Treatment of crab waste-straw mixtures with molasses produced a palatable silage that was efficiently utilized by wethers.

Acetates↗

PubMed1994

Influence of grazing cattle and sheep together and separately on animal performance and forage quality.

Cattle and sheep grazed together and separately from April to October during 3 yr. Initial forage composition was 29% Kentucky bluegrass (Poa pratensis L.), 11% white clover (Trifolium repens L.), and 60% weeds. There were six Angus cow-calf pairs or six ewes (1/2 Dorset x 1/4 Finn x 1/4 Rambouillet) with 11 lambs per each of three pasture replications for single animal species. Six cow-calf pairs plus six ewes and 11 lambs grazed in each of three replications of the mixed animal species treatment. There were approximately one cow and calf or five ewes with lambs per .44 ha. Lambs were weaned at 41 kg or by September 1. Calves were weaned approximately October 10. Lamb daily gain (.23 kg/d), total gain (23 kg), and weaning weights (43 kg) were greater (P < .01) and target weaning weights were reached 14 d earlier in the grazing season when both animal species grazed together than when lambs were in pastures with sheep alone (.18 kg/d, 19 and 38 kg, respectively). Calf gains were not influenced by treatment. Grazing pressure increased throughout the grazing season for cattle alone, peaked in midsummer, and then decreased by autumn for sheep alone, whereas grazing pressure initially increased then remained relatively constant with mixed-species grazing. Forage quality in pastures where sheep grazed alone was lower (P < .05) than in pastures where cattle grazed alone until lambs were weaned in late summer, whereas forage quality with mixed-species grazing was generally intermediate. Mixed grazing resulted in earlier weaning and increased lamb performance and BW of ewes, but not in increased animal production per hectare.

Animal Feed↗

PubMed1993

Managing replacement stock within the environment of the south--plant, soil, and animal interactions: a review.

The South extends from the Atlantic Coast and the Gulf of Mexico north through Virginia and Kentucky and west to the 100th meridian, which extends through Texas and Oklahoma. The soils, environment, and range of adapted forage species offer many and varied opportunities for designing forage-livestock systems for rearing replacement stock. Anti-quality factors of concern when using forages for replacement stock include the presence of Acremonium coenophialum (Morgan-Jones and Gams) in tall fescue (Festuca arundinacea Schreb.), phytoestrogens potentially in several species of Trifolium and Medicago, toxins in some species of brush that contribute to infertility, and imbalances of several minerals including Ca, P, K, Fe, I, Zn, Na, Cu, and Se. Systems should be designed to provide appropriate quality and quantity of forage to produce reproductively active female animals of the desired weight and condition for breeding at the target age, usually 15 mo for beef and dairy heifers and 8 to 9 mo for ewe lambs. Systems generally require sequence grazing of two or more forage species or mixtures to provide extended or year-round grazing opportunities. Stockpiling of tall fescue in the Upper South and use of cool-season annuals in the Lower South extend grazing in autumn, winter, and early spring. Successful systems coordinate plant growth potential with changing animal forage requirements for both quantity and quality of forage to achieve optimum growth rates for replacement stock.

Animal Husbandry↗

PubMed1993

Combined analysis of tall fescue steer grazing studies in the Eastern United States.

The mixed-models procedure (MMP) was used to analyze pooled data sets from 12 independent studies conducted during the last 13 yr at nine locations in seven states to provide combined estimates of daily gains by beef steers (Bos taurus) grazing tall fescue (Festuca arundinacea Schreb.) pastures free of (E-) or infested (E+) at different levels with the endophytic fungus Acremonium coenophialum. Treatments included low-infestation (< or = 5% E+), moderate-infestation (> or = 20 to < or = 35% E+), and high-infestation (> or = 50 to < or = 97% E+) tall fescue pastures, and, in tall fescue-clover (Trifolium spp.) mixtures, pastures at the same E+ levels with approximately 25 and 10% clover in spring and summer stands, respectively. Spring, summer, and combined spring+summer data were analyzed separately. The MMP permitted estimation of the fixed effects of treatments over a broad inference space of future years and different tall fescue pastures over a wide geographic range; detected relationships that had not been apparent in the individual studies, such as the interactions between clover presence and E+ infestation levels; and provided a more coherent body of information than did the results obtained from each discrete study. Logistical and financial constraints that force undesirable compromises in the conduct of future grazing and other expensive or time-consuming research may be avoided by using MMP within the context of cooperative projects.

Acremonium↗

PubMed1992

Forage systems for beef production from conception to slaughter: I. Cow-calf production.

Six year-round, all-forage, three-paddock systems for beef cow-calf production were used to produce five calf crops during a 6-yr period. Forages grazed by cows during spring, summer, and early fall consisted of one paddock of 1) tall fescue (Festuca arundinacea Schreb.)-ladino clover (Trifolium repens L.) or 2) Kentucky blue-grass (Poa pratensis L.)-white clover (Trifolium repens L.). Each of these forage mixtures was combined in a factorial arrangement with two paddocks of either 1) fescue-red clover (Trifolium pratense L.), 2) orchardgrass (Dactylis glomerata L.)-red clover, or 3) orchardgrass-alfalfa (Medicago sativa L.), which were used for hay, creep grazing by calves, and stockpiling for grazing by cows in late fall and winter. Each of the six systems included two replications; each replicate contained 5.8 ha and was grazed by eight Angus cow-calf pairs for a total of 480 cow-calf pairs. Fescue was less than 5% infected with Acremonium coenophialum. Pregnancy rate was 94%. Cows grazing fescue-ladino clover maintained greater (P less than .05) BW than those grazing bluegrass-white clover, and their calves tended (P less than .09) to have slightly greater weaning weights (250 vs 243 kg, respectively). Stockpiled fescue-red clover provided more (P less than .05) grazing days and required less (P less than .05) hay fed to cows than stockpiled orchardgrass plus either red clover or alfalfa. Digestibilities of DM, CP, and ADF, determined with steers, were greater (P less than .05) for the orchardgrass-legume hays than for the fescue-red clover hay. All systems produced satisfactory cattle performance, but fescue-ladino clover combined with fescue-red clover required minimum inputs of harvested feed and maintained excellent stands during 6 yr.

Animal Feed↗

PubMed1992

Forage systems for beef production from conception to slaughter: II. Stocker systems.

Fall weaned Angus calves grazed stockpiled 1) tall fescue (Festuca arundinacea Schreb.), 2) tall fescue-red clover (Trifolium pratense L.), or 3) tall fescue-alfalfa (Medicago sativa L.) or were barn-fed, 4) tall fescue hay, 5) orchardgrass (Dactylis glomerata L.)-alfalfa hay, or 6) tall fescue silage from late October to early April during each of 5 yr. Infection of the fescue with Acremonium coenophialum ranged from 0 to 55%. There were two replications each of steers and heifers for each forage system in a completely random design. Each replicate was grazed by three Angus stockers, except for System 1, which was grazed by six stockers, for a total of 420 stockers. Each pasture replicate contained .8 ha (except System 1, which was 1.6 ha), and the stocking rate was one stocker per .27 ha. Fescue hay and silage were harvested each spring for barn-fed systems from the area stockpiled for grazing by cattle in System 1. Nitrogen fertilizer (90 kg/ha) was applied in early spring and again in early August, before stockpiling; no N was applied to stockpiled fescue grown with legumes. Daily gains by calves grazing stockpiled fescue-alfalfa were greater (P less than .01) than by calves grazing stockpiled fescue-red clover or N-fertilized stockpiled fescue (.50, .33, and .34 kg/d, respectively), but fescue-alfalfa calves required more days (P less than .01) of supplemental hay feeding (105, 60, and 36, respectively). Calves fed fescue hay in the barn gained more (P less than .01) than those fed fescue silage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1991

Seafood processing wastes ensiled with straw: utilization and intake by sheep.

Ensiled mixtures of seafood processing wastes and wheat straw were evaluated. Thirty-six crossbred wethers (average BW = 34 kg) were fed 1) a basal diet (hay and concentrate) alone, or a 1:1 ratio (DM basis) of basal and 2) ensiled fish waste plus straw (70:30, wet basis), 3) ensiled fish waste and straw (51:49), 4) ensiled crab waste plus straw (60:40), 5) ensiled crab waste plus straw (40:60), or 6) ensiled wheat straw (50% moisture). Dry molasses (5%) was included in all ensiled mixtures, and glacial acetic acid (16% vol/wt) was added to the crab waste mixtures. Among diets containing ensiled fish waste, DM digestibility was greater (P less than .01) for the diet containing silate with 70% fish waste than the diet containing 51% fish waste. There was no difference (P greater than .05) in DM digestibility between the two crab waste silages. Apparent digestibility of CP was greater (P less than .01) for diets containing fish than for those containing crab waste. Nitrogen retention (g/d) was positive for sheep receiving all diets but not different among treatments. Apparent absorption of P (g/d) was greater (P less than .01) by sheep fed fish waste silage diets than by those fed crab waste silage diets. Among seafood silages, DMI was greater (P less than .01) for sheep consuming the 60:40 than for those consuming the 40:60 crab waste silage diet and less (P less than .01) for sheep fed the 70:30 than for those fed the 51:49 fish waste silage diet. Seafood processing wastes potentially are valuable to ensile with crop residues for use as ruminant feedstuffs.

Absorption↗

PubMed1991

Nutrient utilization by sheep fed forage grown on soil treated with fluidized-bed combustion residue.

A mineral balance trial was conducted with 18 wether lambs fed sun-cured hay harvested from pastures located on a reclaimed strip-mined site. The following soil applications were made during each of 3 yr: 1) none, 2) dolomitic limestone and 3) fluidized-bed combustion residue (FBCR). Because FBCR had half the buffering capacity of limestone, it was applied at twice the rate of limestone. Apparent digestibility of hemicellulose was higher (P less than .05) for limestone-amended forage than for FBCR-amended forage (70.2 vs 67.0%), and apparent digestibility of cellulose was higher (P less than .05) for amended forages (66.7%) than for the control (63.9%). Apparent absorption and retention of N were similar among treatments, when expressed as a percentage of intake. Lambs fed control forage were in negative Ca balance, lower (P less than .01) than with amended forages. Apparent absorption and retention of Mg and Fe (g/d basis) were higher (P less than .05) for lambs on the limestone treatment than for lambs on the FBCR treatment. Apparent absorption of S was higher (P less than .01) for lambs on the FBCR treatment than for those on the limestone treatment. These differences were related to differences in mineral concentrations of the forages. Serum P was lower (P less than .05) for lambs fed FBCR-treated forage than for lambs fed limestone-treated forage (10.1 vs 12.9 mg/dl). Soil amendment with FBCR did not have deleterious effects on digestibility or mineral metabolism; in fact, it may have enhanced utilization of Ca and S and improved digestibility of some fiber components by lambs.

Animal Feed↗

PubMed1991

Influence of aluminum-citrate and citric acid on tissue mineral composition in wether sheep.

A 60-d trial was conducted to determine effects of A1-citrate and citric acid on tissue mineral composition in wether lambs. Eighteen crossbred, yearling wether lambs equipped with ruminal cannulas were fed a diet containing low (.12%) Mg and high (2.87%) K (DM basis) and were allotted to three treatments: 1) control; 2) 2,000 micrograms A1 as A1-citrate/g of diet DM and 3) citric acid equivalent to the citrate in treatment 2. Treatments were administered in 200 ml of deionized water twice daily in divided doses via ruminal cannula. At the end of 60 d, wethers were slaughtered and samples of rib and tibia bone, liver, kidney, brain, spleen, pancreas, parathyroid and pituitary gland were analyzed for mineral concentration. Concentrations of A1 increased (P less than .05) in rib, tibia, liver, kidney, spleen and pituitary gland and tended to increase in brain (P less than .13) in wethers treated with A1-citrate compared to citric acid. Magnesium was decreased in rib (P less than .01) and tended to be decreased in pituitary gland (P less than .15), whereas Ca tended to be decreased in pancreas (P less than .07), kidney (P less than .11) and parathyroid (P less than .10) by A1-citrate treatment compared to citric acid. Potassium decreased (P less than .01) in liver, Fe increased (P less than .05) in kidney, Zn decreased in pituitary (P less than .05) and tended to decrease in pancreas (P less than .10) due to A1-citrate but not citric acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗

PubMed1991

Apparent digestibility and nutrient balance in lambs fed different levels of flatpea hay.

Apparent digestibility and nutrient utilization were studied in a digestion and balance trial with 30 wether lambs (BW 32 kg). Lambs were blocked by weight and allotted randomly to five diets with ratios of alfalfa (Medicago sativa L.) to 'Lathco' flatpea (Lathyrus sylvestris L.) hay of 100:0, 75:25, 50:50, 25:75, and 0:100. Alfalfa was harvested in the early bloom stage and flatpea was harvested in the vegetative stage. Digestibilities of DM, NDF, ADF, cellulose, hemicellulose, and energy decreased linearly (P less than .05) as the level of flatpea hay increased to values of 53.3, 32.4, 39.9, 46.0, 40.5, and 52.5%, respectively, for 100% flatpea hay. Nitrogen retention (9 to 15% of intake) was not affected by level of flatpea hay. Ruminal pH, NH3 N, and blood urea N increased linearly (P less than .001) as level of flatpea increased in the diet, apparently a reflection of dietary N level. Calcium excretion decreased linearly (P less than .01) with increased proportions of flatpea hay and was related to dietary intake of Ca. Apparent absorption and retention showed a cubic effect (P less than .05). No clinical signs of toxicity were observed in any of the lambs during the 20-d metabolism trial. Vegetative flatpea is potentially valuable as a forage for feeding ruminants.

Animal Feed↗

PubMed1990

Influence of aluminum citrate and citric acid on mineral metabolism in wether sheep.

A 60-d trial was conducted to determine effects of Al citrate and citric acid on DM digestibility (DMD) and metabolism of Mg, Ca, P, K, Na and Al. Eighteen crossbred, yearling wether lambs equipped with ruminal cannulas were fed a basal diet containing .12% Mg and 2.87% K (DM basis) and were allotted to three treatments: 1) control, 2) 2,000 ppm Al as Al citrate and 3) citric acid equivalent to the citrate in treatment 2. Treatments were administered in 200 ml of deionized water twice daily in divided doses via ruminal cannula. Balance trials were conducted during d 0 to 5, 6 to 10, 25 to 35 and 50 to 60. Dry matter digestibility decreased (P less than .05) approximately 3 percentage units in lambs receiving Al. Treatment with Al citrate increased (P less than .01) apparent absorption and retention of Al compared to those receiving citric acid alone. Approximately 30% of ingested and infused Al was apparently absorbed. Compared to citric acid, Al citrate treatment lowered apparent absorption and retention of Mg and Ca during d 0 to 5. Apparent Ca absorption and retention again were lowered during d 50 to 60. Urinary Ca was increased (P less than .01) and apparent P absorption (P less than .10) and retention (P less than .05) were decreased by Al citrate during all measurement periods. Apparent absorption of K decreased (P less than .05) slightly in response to Al treatment. Apparent absorption of Na was not influenced by Al treatment. Serum Mg and P decreased and serum Ca increased in response to Al treatment. Results demonstrate negative effects of ingested Al, but not of citric acid, on DMD and metabolism of Mg, Ca, P and K.

Absorption↗

PubMed1989

Factors influencing magnesium absorption and metabolism in ruminants.

Magnesium is a nutrient required for all animals, but it is especially critical for ruminants. A physiological deficiency of Mg results in hypomagnesemic tetany. Typically, only female ruminants are affected, and the disturbance usually occurs during the early stages of lactation. Magnesium functions at three biochemical levels, as a cofactor at the enzymatic level, at the structural level in assembly of ribosomes, and at the whole cell level as a stabilizing force in membranes. Parathyroid hormone (PTH) can affect Mg metabolism by decreasing urinary Mg excretion and stimulating bone resorption, thus releasing Mg into the extracellular fluid. Renal excretion of Mg and Mg absorption from the gastrointestinal tract both are increased by 1,25-dihydroxyvitamin D3. A number of dietary factors depress Mg absorption in ruminants. Of these, high dietary K has the greatest and most consistent effect. Feeding substantial quantities of readily digested carbohydrates increases Mg absorption, but the mode of action is not clear. High concentrations of Al in forage sometimes are associated with a high incidence of grass tetany, but this effect does not appear to be related to Mg absorption. Interrelationships of Al with Mg, Ca, P and PTH are implicated.

Absorption↗

PubMed1986

Influence of ingestion of aluminum, citric acid and soil on mineral metabolism of lactating beef cows.

Lactating beef cows (16 Hereford and 34 Angus, 430 kg average body weight, aged 8 to 10 yr) were fed a basal diet containing 200 micrograms/g Al alone or supplemented with Al-citrate, citric acid, soil or soil plus citric acid for 56 d. Diets containing Al-citrate, soil and soil plus citric acid contained 1,730, 1,870 and 1,935 micrograms/g Al, dry-basis, respectively. Adding soil to the diet also increased Mg and Fe content of the diet. Aluminum values in ruminal contents of beef cows fed the basal alone or supplemented with citric acid, Al-citrate, soil or soil plus citric acid were 800, 990, 2,930, 3,410 and 2,910 micrograms/g, air-dry basis, respectively. Serum Mg and inorganic P declined (P less than .01) and urinary Ca concentration increased (P less than .01) for cows fed Al-citrate. By d 56, serum Mg was 1.5 and 2.2 mg/dl, and serum P was 3.8 and 6.8 mg/dl, for cows fed Al-citrate and basal diets, respectively. Calcium concentrations in urine were 281 and 11 micrograms/g for cows fed Al-citrate and basal diets, respectively. Citric acid, soil and soil plus citric acid had no detrimental effects on serum Mg and inorganic P, or urinary Ca concentration. By d 56, serum Ca was higher (P less than .06) in cows fed Al-citrate, compared with cows on the other four diets. Bone Ca, P, Zn and percent ash were not significantly affected by treatment but bone Mg tended to be slightly lower (P less than .07) for cows fed Al-citrate.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗

PubMed1986

Effect of sulfur fertilization on chemical composition, ensiling characteristics and utilization of corn silage by lambs.

Effects of S fertilization, 0 or 67 kg S/ha, as (NH4)2SO4, as a single or split application on chemical composition, ensiling characteristics and utilization of corn (Zea mays L.) silage by wether lambs was investigated. Corn forages were ensiled at hard-dent stage at 35% dry matter (DM). Sulfur fertilization increased (P less than .01) total S and SO4 but had no effect on N, Mg, Ca or fiber components in silages. Sulfur-fertilized corn silages (N:S = 42 and 43) and non-S fertilized silage (N:S = 62) were fed alone and supplemented with Na2SO4 at two rates to achieve N:S ratios of 12 (high) and 45 (low, to approximate S-fertilized silage), to 30 wether lambs (Suffolk and Dorset crosses) in metabolism and palatability trials. Both trials were randomized complete-block designs. Lambs weighed 36 and 41 kg, respectively. All silages were supplemented with 6.7 g urea/d. Digestibility of DM and cell wall components, and apparent absorption of S and N were increased (P less than .05) by S fertilization and supplementation. Nitrogen retention was increased (P less than .01) by S fertilization and supplementation. Retention was higher (P less than .001) for lambs that were fed S-fertilized silage, compared with supplementation to achieve a similar N:S ratio. It appears that S fertilization was more effective than S supplementation in improving efficiency of N utilization.

Ammonia↗

PubMed1984

Influence of aluminum as sulfate, chloride and citrate on magnesium and calcium metabolism in sheep.

Three metabolism trials were conducted to determine the effects of Al as sulfate (SO4), chloride (Cl) and citrate on metabolism of Al, Mg, Ca and serum concentrations of Mg and Ca. Twelve wether lambs, equipped with rumen cannulas and blocked by breeding and weight, were allotted randomly to the following six treatments during each of three trials: 0, 1,000 and 2,000 pm Al as SO4 or Cl; or 2,000 ppm Al as citrate. Treatments were administered in 200 ml of deionized water twice daily in divided doses via rumen cannula. Lambs were fed 1,000 g/d of chopped tall fescue hay (Festuca arundinacea, Schreb. IFN 1-09-187). Aluminum, Mg and Ca in feces and urine, and Mg and Ca in blood serum were determined daily over the 10-d treatment period. Means were calculated for d 6 through d 10. By d 6, serum Mg was lowered (P less than .05) for lambs administered 2,000 ppm Al as citrate. Serum Ca was not affected by Al treatments. Neither Mg nor Ca absorption was significantly affected by Al treatment. Urinary excretion of Ca increased linearly (P less than .001) with all treatments. Absorption of Al occurred with all forms of the element and was highest for Al2(SO4)3, expressed as percentage of intake.

Alum Compounds↗

PubMed1984

Influence of dietary aluminum on nutrient utilization in ruminants.

Aluminum enters the ruminant diet through plant-accumulated Al, soil ingestion, feed and water contamination, and as an additive to alter metabolism or absorption of other minerals. Ingested Al is usually poorly absorbed and has been shown to depress utilization of dietary F and P, largely due to the formation of insoluble, nonabsorbable Al complexes. Aluminum has been suggested for use in alleviating F toxicosis in ruminants. Increases in fecal F and decreases in dental lesions and bone F content have been observed by some researchers in response to dietary Al. The Al content of certain P supplements has been associated with poor P utilization. Levels of 1,450 ppm Al as AlCl3 in the diet of lambs lowered P absorption and resulted in a need for increased dietary P. It has been suggested that absorbed Al decreases P incorporation into DNA and RNA, with shifts of ATP to AMP and ADP. Aluminum administration has resulted in alterations in carbohydrate metabolism in rats and in parathyroid function in man. In sheep, 2,000 ppm dietary Al as AlCl3 depressed kidney Mg and plasma Mg and P concentrations. Sheep dosed via rumen cannula with 2,000 ppm Al as citrate, exhibited lower serum Mg and increased urinary Ca excretion. Steers dosed via rumen cannula with 4,000 ppm Al as Al2 (SO4)3 had lowered serum Mg values within 24 h.

Aluminum↗

PubMedDate not supplied

Evaluating evidence against diagnostic hypotheses in clinical decision making by students, residents and physicians.

Clinicians are faced with the difficulty of filtering large quantities of information and incorporating evidence to make safe and accurate diagnostic, therapeutic and management decisions. One solution to this difficulty is the development of evidence-based decision support tools designed to provide relevant and up-to-date evidence to clinicians. However, as investigations of medical decision making have found that hypothesis generation and clinical reasoning differ as a function of expertise, the gathering, interpretation and use of evidence against hypotheses depends on the prior knowledge of the clinician. The specific focus of the study is to understand how clinical evidence is gathered and evaluated during diagnostic reasoning. Verbal data during clinical interactions with physicians, residents and final year medical students were collected and transcribed. The dialogues were analyzed using three levels of coding: cognitive, epistemological and linguistic pragmatic perspectives. Results show that: (a) the ability to index and use adequate evidence by physicians, residents and students is a function of the early generation of accurate hypotheses: and (b) strategies for resolving inconsistent evidence differ as a function of medical expertise. The relationship between these findings and its application for the development of adequate knowledge-based systems for indexing and retrieval is discussed.

Clinical Competence↗

PubMedDate not supplied

Representing clinical guidelines in GLIF: individual and collaborative expertise.

OBJECTIVE: An evaluation of the cognitive processes used in the translation of a clinical guideline from text into an encoded form so that it can be shared among medical institutions. DESIGN: A comparative study at three sites regarding the generation of individual and collaborative representations of a guideline for the management of encephalopathy using the GuideLine Interchange Format (GLIF) developed by members of the InterMed Collaboratory. MEASUREMENTS: Using theories and methods of cognitive science, the study involves a detailed analysis of the cognitive processes used in generating representations in GLIF. The resulting process-outcome measures are used to compare subjects with various types of computer science or clinical expertise and from different institutions. RESULTS: Consistent with prior studies of text comprehension and expertise, the variability in strategies was found to be dependent on the degree of prior experience and knowledge of the domain. Differing both in content and structure, the representations developed by physicians were found to have additional information and organization not explicitly stated in the guidelines, reflecting the physicians' understanding of the underlying pathophysiology. The computer scientists developed more literal representations of the guidelines; addition were mostly limited to specifications mandated by the logic of GLIF itself. Collaboration between physicians and computer scientists resulted in consistent representations that were more than the sum of the separate parts, in that both domain-specific knowledge of medicine and generic knowledge of guideline structure were seamlessly integrated. CONCLUSION: Because of the variable construction of guideline representations, understanding the processes and limitations involved in their generation is important in developing strategies to construct shared representations that are both accurate and efficient. The encoded guidelines developed by teams that include both clinicians and experts in computer-based representations are preferable to those developed by individuals of either type working alone.

Brain Diseases↗