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Biomedical subjects

R Crockett

Publications and source records attributed to R Crockett.

At least 19 recordsLinked to original sources

Assessing the implementation process.

A Computerized Patient Record System (CPRS) has many benefits and could improve health care outcomes. Reaping these benefits, however, is dependent on successful implementation of a provider order entry system. The literature supports substantial evidence that even systems that are usable, effective and reliable have not been adopted by the intended users. A successful implementation may be substantially a function of the degree to which the processes of care have changed to adapt to the new system. To ensure successful implementation we suggest monitoring the implementation process itself. The purpose of this paper is to report the methodology we developed for assessing how successfully a provider order entry system is being implemented. We adopt a model of diffusion of information technology developed by Fichman (1994) and expanded by Ash (1997). In this model, diffusion is characterized be three categories, "breadth" (infusion) and "depth" (diffusion) and "quality" (appropriateness of use). In this paper we discuss the typology of diffusion and describe specific measures designed to measure infusion and diffusion of a hospital information system.

Diffusion of Innovation↗

Does user satisfaction relate to adoption behavior?: an exploratory analysis using CPRS implementation.

User satisfaction is commonly assessed in evaluations of information systems as a proxy for user adoption. However few studies actually report directly assessing the relationship between the two constructs. In this study the relationship between four user satisfaction measures and five adoption behaviors were explored in the context of the implementation of the Veteran's Health Administration Computerized Patient Record System 1.0. Findings suggest that the relationship is modest and depends on the measurement system used. Specifically, direct reports of affect and judgements of specific task efficacy related to behavior more often than usability and a general user satisfaction instrument.

Attitude to Computers↗

The hepatopulmonary syndrome: radiologic findings in 10 patients.

OBJECTIVE: The purpose of this study was to review the radiologic manifestations of the hepatopulmonary syndrome. MATERIALS AND METHODS: We retrospectively reviewed clinical records, chest radiographs, 99m Tc-macroaggregated albumin (MAA) perfusion lung scans, chest CT scans, and pulmonary angiograms of 10 patients with proven hepatopulmonary syndrome. RESULTS: Chest radiographs showed basilar, medium-sized (1.5-3.0 mm) nodular or reticulonodular opacities in all cases. CT was done in eight cases and showed basilar dilatation of lung vessels with a larger than normal number of visible branches. The vascular basis for these opacities was best appreciated on conventional CT scans of 10-mm sections. No individual arteriovenous malformations were seen on CT scans. High-resolution CT scans showed no evidence of interstitial fibrosis. 99mTc-MAA perfusion lung imaging, done in seven patients, showed pulmonary arteriovenous shunting in five. Contrast echocardiography confirmed intrapulmonary shunting in these five patients. Pulmonary angiography, done in four cases, showed subtle distal vascular dilatation in two and moderate dilatation with early venous filling in two but did not reveal any individual arteriovenous malformations. CONCLUSION: Chest radiographs in hepatopulmonary syndrome usually show bibasilar nodular or reticulonodular opacities. Conventional CT shows that these opacities represent dilated lung vessels. High-resolution CT is useful in excluding pulmonary fibrosis or emphysema as the cause of these opacities. 99mTc-MMA perfusion imaging or contrast echocardiography can be used to confirm intrapulmonary arteriovenous shunting.

Adult↗

Serum fatty acid profiles in type I and type II diabetes: metabolic alterations of fatty acids of the main serum lipids.

Fatty acid profiles of various lipid fractions were determined in carefully selected insulin-dependent and non-insulin-dependent diabetics to assess relationships between serum fatty acid composition and type of diabetes. Clear-cut hypertriglyceridemia with slight hypercholesterolemia was found in both diabetic types. The decrease of lignoceric acid in sphingomyelin is the only alteration found in both types of diabetes. In the insulin-dependent diabetics, there were increases in levels of oleic acid and of alpha-linolenic acid in esterified cholesterol, and in levels of alpha-linolenic acid in the triglyceride fraction. In the non-insulin-dependent diabetics, there were increases in levels of oleic acid and total monounsaturated fatty acids in the triglyceride fraction and there was an increase in levels of saturated fatty acids and a decrease in levels of polyunsaturated acids in phosphatidylcholine; in sphingomyelin, dihomogamma-linoleic acid levels were enhanced. Arachidonic acid levels were normal in our patient population.

Adult↗

Dual metabolic pathways of 12-HETE in rat aortic smooth muscle cells.

12(S)-HETE, a major lipoxygenase-derived compound from arachidonic acid is incorporated and metabolized by vascular smooth muscle cells via beta-oxidation. We have now identified for the first time in this cell type 12(S)-HETE metabolites formed by a combination of reductase and oxidation pathways. HPLC and GC-MS analysis of time-course experiments allow us to characterize two different metabolic pathways: a direct peroxisomal beta-oxidation of 12(S)-HETE leading to the formation of 16:3 (8-OH) which accumulates first and a reduction of one of the conjugated double bonds of 12(S)-HETE giving the dihydro-intermediate 20:3(12-OH) that transiently accumulates before being converted itself by peroxisomal beta-oxidation to 16:2(8-OH). Taken together these results may suggest that the transient accumulation of 20:3(12-OH) through transcellular metabolism of 12(S)-HETE may represent a part of the modulatory effect of 12(S)-HETE on vascular function.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

Evaluation of plasmatic leucocyte elastase levels in coronary artery disease.

Leucocyte elastase may be involved in the structural modification observed in the atherosclerotic process. Therefore, we tested the usefulness of leucocyte elastase plasma level determination as a marker for atherosclerosis. Plasma levels of elastase were determined by ELISA in 100 consecutive patients (mean age 56 +/- 9.8 years) admitted to hospital for coronary angiographic investigation of chest pain. Eighty-seven patients had evidence of atherosclerosis, and 13 patients had normal coronary vessels. No significant difference in leucocyte elastase was found between the 2 groups, nor was there any relationship between elastase levels and the severity of atherosclerosis. However, relationships between plasma leucocyte elastase levels and various lipid fractions (Apo AI, LDL) and daily tobacco consumption were found. Leucocyte elastase may thus play a role not only by direct modification of the vessel wall, but also indirectly via risk factors such as dyslipoproteinemia and leucocyte toxicity.

Coronary Angiography↗

Serum type III procollagen peptide levels in coronary artery disease (a marker of atherosclerosis).

The known shift in collagen synthesis from procollagen type I to type III in patients with atherosclerosis, suggested measurement of serum procollagen III peptide (PIIIP) levels in patients with coronary artery disease (CAD). Two groups of patients were studied: group I--thirty-six patients with CAD (male, mean age 56.9 +/- 7.5 years, hospitalized for coronary angiography. Risk factors included 16 patients with high blood pressure, four diabetics, 31 smokers and 15 with hypercholesterolaemia. Five patients had no significant lesions, seven had one vessel with over 50% stenosis, 10 had two vessels and 14 had three vessels. Group II--35 patients (male, mean age 39.4 +/- 13.3 years), with normal physical examination and ECG according to WHO criteria, formed the control group: the risk factors included nine patients with high blood pressure, 14 smokers and one with hypercholesterolaemia. Procollagen III peptide levels were determined by radioimmunoassay. In group I, PIIIP levels were 26.8 +/- 16 ng ml-1 vs. 10.4 +/- 3.2 for group II. Sixty-one per cent of group I had pathological levels of PIIIP with an absence of correlation with the severity of atherosclerosis or risk factors. Only 2.8% of patients in group II had pathological levels. Procollagen III peptide determination would appear to be a sensitive, specific and predictive test for atherosclerosis in patients with CAD.

Adult↗

[Protease inhibitors and ectasia in coronary atherosclerosis].

The possibility of elastase contributing to degradation of the arterial wall in atherosclerosis and to the formation of ectasia has prompted us to assay the main protease inhibitors, alpha 1-antitrypsin and alpha 2-macroglobulin, in patients with angiographic coronary disease with and without coronary ectasia. Serum concentrations of these two proteins were measured by immunonephelometry in 203 patients admitted for coronary arteriography. The results obtained were analyzed according to the presence of atheromatous lesions and their severity and to the presence or absence of ectasia. There was no correlation between the values observed and the presence or severity of coronary atherosclerosis, but the concentration of alpha 1-antitrypsin was significantly higher in patients with coronary ectasia (247.2 +/- 40.5 mg/ml) than in patients without ectasia (213.5 +/- 36.6 mg/100 ml; p less than 0.001). This study shows that coronary ectasia is associated with disturbances in the protease-antiprotease system, which may be consecutive to initial changes in elastase activity. Our results support the theory that elastase and protease inhibitors play a specific role in some atheromatous processes.

Adult↗

Circadian rhythm in gamma glutamyltranspeptidase and leucine aminopeptidase urinary activity in rats.

Urinary gamma glutamyltranspeptidase (GGT) and leucine aminopeptidase (LAP), renal tubular brush border enzymes, have been shown to be sensitive indicators of renal tubular functions. This study documents circadian rhythms in the urinary activity of GGT and LAP, statistically validated and quantified by the cosinor method, in 15 male Wistar rats standardized to a LD 12:12 illumination schedule (light from 0800 hr to 2000 hr) and fed ad libitum. The acrophase of the circadian rhythms in urinary GGT and LAP activity occurred at the end of the rest span of the animals: between 1730 and 1915 for GGT (depending on the mode of expression of the activity) and between 1700 and 1910 for LAP. Of striking resemblance in their timing, both these rhythms were also of large amplitude (about 50% of the mesor for urinary GGT activity and about 45% for LAP one). The circadian acrophases of urinary GGT and LAP activity led in timing the circadian rhythms in urine volume and creatinine excretion by about 13 hr. Such findings consistent with the circadian variations found by other investigators in GGT in kidney homogenates or in LAP in human urine thus reflect a periodicity in renal tubular function. The reasons for these circadian variations, still unknown at this time, are discussed. The influence recently demonstrated of the hormonal context on protein and enzyme synthesis at the tubule, and its phase relations to urinary enzyme excretion emphasize how much the circadian rhythm in urinary GGT and LAP activity is well included in the murine time structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

[Metabolism of collagen in coronary patients].

The alterations observed in connective tissue of the arterial wall and dermis in atherosclerosis incited us to investigate collagen metabolism in patients with coronary disease. We first studied collagen metabolism in fibroblast cultures, then measured serum levels of type III procollagen aminoterminal peptide. Fibroblast collagen metabolism was investigated in 12 consecutive patients of less than 45 years of age presenting with coronary disease and coronary atherosclerosis was found to be preserved in patients with atherosclerosis, but less type III type I procollagen was synthesized (14.6 +/- 6.6% versus 22.3 +/- 4.3%). This abnormality, found in 83% of our coronary patients, seemed to be unrelated to risk factors or to the severity of atherosclerosis. Serum type III procollagen aminoterminal peptide was assayed comparatively in 36 patients with coronary atherosclerosis confirmed at coronary-ventriculography and in 35 patients free from coronary disease as defined by the W.H.O. criteria. Serum levels of this peptide were significantly higher in patients with coronary atherosclerosis (26.76 +/- 16 ng/ml) than in controls (10.43 +/- 3.18 ng/ml). 61% of coronary patients had a peptide level higher than the normal value (17 ng/ml). No correlation was found between this rise in type III procollagen aminoterminal peptide and the severity of coronary lesions or the importance of risk factors. Thus, collagen metabolism is altered in coronary patients, and this alteration can be detected by a peripheral marker. However, the use of this marker to diagnose the presence or evaluate the course of atherosclerosis requires clarification.

Adult↗

[Diffusion of amikacin in the lungs].

The authors report their findings on amikacin concentrations in serum and in the lungs, its diffusion in the parenchyma of the lungs--evaluated from the ratio tissue/serum concentrations, and they also compare their results with those registered during a study on dibekacin, tobramycin and netilmicin, designed according to the same protocol. Ten patients with bronchial carcinoma who had to undergo chirurgical excision, received 5 IM injections at 12-hourly intervals. The dose administrated at each injection was 7.5 mg/kg. The assay of amikacin was realized by HPLC. Serum concentrations at the presumed peak (17 micrograms/ml) and 12 hours after that were somewhat lower than those reported by other authors. The mean tissue concentrations 2 h 20 min. after the last injection were 14,95 +/- 4,52 micrograms/g in the normal parenchyma, and 16,18 +/- 3,67 micrograms/g in the pathological parenchyma. The ratio concentrations in the tissues and in serum were comparable for both the normal and pathological parenchyma. Compared to dibekacin, tobramycin and netilmicin, this study confirms the large distribution of the aminoglycosides in the lung parenchyma. The behaviour of dibekacin and tobramycin with regard to the pathological parenchyma is rather comparable; netilmicin better penetrates into the normal parenchyma, and the diffusion of amikacin is parallel for both the normal and pathological tissues.

Amikacin↗

Revised locations of the hisI and pru (proline utilization) genes on the Pseudomonas aeruginosa chromosome map.

The location of genes in the vicinity of the major FP2 origin on the chromosome of Pseudomonas aeruginosa PAO has been revised. The markers hisI (a transduction group of histidine biosynthetic genes) and pru (a gene cluster encoding proline utilization functions) were located in the 90 to 95/0 min chromosome region by a series of plate matings mediated by R68.45. Three-factor-crosses using this plasmid established the following marker order: pur-67 pru hisI/cys-59 proB ilvB/C. Genetic evidence is presented to confirm the previous observations that FP2 can mobilize the chromosome from at least two origins near proB and in both directions. Thus, when markers in this chromosome region are analyzed by FP2 crosses only, the mapping data may be difficult to interpret. This complication can be overcome by the use of R68.45 and Tfr (transposon-facilitated recombination) or Hfr donors.

Chromosome Mapping↗

High density lipoprotein cholesterol and apoprotein A1 in healthy volunteers during long-term moderate alcohol intake.

Moderate alcohol consumption is associated with lower cardiovascular mortality. The effect of moderate alcohol intake during 5 weeks on lipoproteins, especially on the high density lipoprotein (HDL) cholesterol total (of which the levels are inversely predictive of coronary heart disease) and apoproteins A, A1 and B, was studied in 7 normal men. HDL cholesterol total appreciated by the heparin manganese precipitation method and phosphotungstate magnesium method increased (p less than 0.01) during alcohol consumption. The composition of HDL was modified by alcohol consumption: increase of the esterified/total cholesterol ratio (p less than 0.05) and phospholipids (p less than 0.05) without significant modification of triglycerides. Low density lipoprotein and very low density lipoprotein did not vary significantly. Apoprotein A1 increased during alcohol consumption (p less than 0.05) with a transitory increase of apoprotein A. There was no significant modification of apoprotein B.

Adult↗

[Circadian rhythms in rat and mouse urinary electrolytes and nitrogen derivatives excretion (author's transl)].

The present study considers circadian rhythms of excretion of six solutes in the urine of 40 rats and 100 mice collected during eight consecutive, six-hour long periods. 1. The different chronograms evidence significant diurnal variations in water, sodium, potassium, urea, creatinine and proteins excretion of the two rodent urines. To compare easily the circadian variations in rat and mouse (with very marked differences in excretion intensities), the value of each urinary solute for each six-hour period is given as a percent of the total 24 hours excretion. 2. Daily excretion represents only 34 to 44% of the total 24 hour excretion. 3. These variations are exactly reproduced on the two consecutive days. 4. Chronogram drawings of the circadian variations of these six urinary solutes are very comparable in each rodent. 5. Moreover, these circadian variations in excretion are very similar, when compared in rat and mouse; the difference between homologous values in the two rodents is less than 2% in 2/3 of the cases.

Animals↗

[Distribution of the fatty acids of the oyster C. gigas in different lipid fractions].

Extraction of oyster lipids were carried out on total wet organic tissues with a mixture of chloroform-methanol. The different fractions of polar and not polar lipids were separated by thin layer chromatography (TLC) and the methyl esters of the constituant fatty acids has been prepared by transmethylation a cold for use in subsequent gas-liquid chromatography (open tubular gas chromatography). The oyster contained considerable proportions of C16:0 and heiglhly unsaturated acids (specially in lecithin and cephalin) of C20, C22 series which are characteristic of the lipids of most acquatic plants and animals. Studies were made of the seasonal variations.

Animals↗

[Study of the composition of aqueous humor in normal subjects by means of automatic analytical technics].

Five new constituents in the aqueous humour were measured as part of a study on the constitution of the aqueous in normal subjects; urea, glucose, phosphorus, calcium and the carbonates and bicarbonates representing the alkaline reserve. Each of these constituents were measured by an automatic method using the Technicon auto-analyser, a similar sample of aqueous humour serving in some cases for simultaneous measurement of several constituents. The principles of the reaction, the Manifold used and the results obtained are reported for each of these. The latter were studied more particularly as a function of age on the one part and also a function of the serum levels of the same constituent. This simultaneous study establishes a relationship between the aqueous humor and the plasma which is compared with preceding reports in the literature and with results obtained more often in animals. Several important physiological and physiopathological considerations arise from these findings.

Adult↗