Reducing stress among junior doctors
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Journal Article↗
Biomedical subjects
C Luck
Publications and source records attributed to C Luck.
Congenital anterior abdominal wall defects. A national congenital malformations register is needed.
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Abdominal Muscles↗
Fluid dynamics of the CarboMedics kinetic bileaflet prosthetic heart valve.
OBJECTIVE: To compare hydrodynamic characteristics of a new bileaflet heart valve, the CarboMedics kinetic cardiac valve prosthesis, with those of a St. Jude Medical (SJM) heart valve. METHODS: Hydrodynamic characteristics were determined in the mitral and aortic positions of a Vivitro Systems pulse duplicator for size 23 Kinetic aortic values, size 23 SJM aortic valves, size 29 Kinetic mitral valves and size 29 SJM mitral valves. Test conditions were 72 beats per min with cardiac outputs of 2, 5 and 7 l/min. Values of forward flow pressure drop (delta P), regurgitant and energy loss were determined for each valve. The test results for the two valve designs were compared by valve size. RESULTS: The test results show that both the size 23 and size 29 Kinetic valves have 8-14% lower delta P values and 5-10% greater effective orifice area (EOA) values. The size 29 Kinetic mitral valve has a 1-2 ml lower regurgitant volume, while the size 23 Kinetic aortic valve has a 0.5 ml greater regurgitant volume than the corresponding SJM values. These factors combine to provide a 5-10% lower energy loss for size 23 Kinetic aortic valves and a 15-25% lower energy loss for size 29 Kinetic mitral valves over the cardiac cycle than for corresponding sizes of SJM valves. CONCLUSIONS: The Kinetic valve's fluid dynamics are superior to equivalent sizes of SJM valves. This is especially impressive considering that the tissue annulus diameters for Kinetic valves are approximately 0.5 mm less than equivalent size SJM valves. The primary reasons for the superior hydrodynamic performance of Kinetic valves are (1) the larger orifices which result in lower forward flow delta P values and (2) the opening angles, which have been customized for each valve size to minimize energy loss.
Aortic Valve↗
An approach to improving hospital advertising.
Newspaper ads from hospitals in Ohio were rated for their effectiveness and explicit use of marketing principles. Analysis showed that the advertising could be improved by increasing the motivation for action, emphasizing how the organization's products and services are different from competitors and more thoroughly identifying the benefits the consumer would receive. Use of the two forms in the study can contribute to improved health care advertising.
Advertising↗
[Fatty acid composition and cholesterol content in naturally canned jurel, sardine, salmon, and tuna].
To obtain more information about fatty acid profile and cholesterol content of fat extracted from canned fish in brine habitually consumed in Chile, four different species Jurel (Trachurus murphyi), Sardine (Sardinops sagax), Salmon (Oncorhynchus kisutch) and Tuna (Thunnus alalunga) were analyzed. The GLC of fatty acid methyl esters showed that the main group of fatty acids belongs to polyunsaturated, being omega-3 family the more important. The principal representants were eicosapentaenoic (EPA) and docosahexaenoic acids (DHA), with percentages between 5%-11% and 12%-22% respectively. Omega-6 family was represented mainly by arachidonic acid (AA) with percentages between 2%-4%. Cholesterol content was similar to the values found in other animal origen meats. The figures were between 41-86 mg of cholesterol per 100 g of edible product, Tuna in brine, was the product with the lowest content of cholesterol. The calculated amount of EPA, DHA and total omega-3 fatty acids indicated values between 95-604, 390-1163 and 609-2775 mg respectively per 100 g of edible product. Due these results is important to emphasize the consumption of this type of canned fish in brine, that they really represent a good dietary source of mainly polyunsaturated omega-3 fatty acids. The international recommendations indicate to increase the consumption of fish, due the beneficial effects described in relation with cardiovascular disease, which is the mean cause of death in Chile, country with a wide variety of marine origen foods, but with a contradictory answer about its consumption which is not incorporated in the current diet.
Animals↗
Pharmacokinetics, metabolism and biliary and urinary excretion of oral ramipril in man.
In order to evaluate the pharmacokinetics and excretion of ramipril in man, 8 cholecystectomy patients aged between 53 and 68 years received 5 mg ramipril orally as a single dose. All patients had a T-drain inserted to permit bile collection; all gave their informed consent to participate in the trial. Serum samples were collected half-hourly until 2 hours, then hourly until 6 hours, then at 8, 10, 24 and 25 hours after intake. Urine was collected in 2-hour fractions until 8 hours, followed by a 4- and a 12-hour fraction. Bile was collected hourly until 6 hours, followed by a 6- and a 12-hour collecting fraction. Concentrations of ramipril and ramiprilat in serum, and determinations in urine and bile of ramipril, ramiprilat, ramipril glucuronide, ramiprilat glucuronide, diketopiperazine and diketopiperazine acid were made; total amounts excreted were calculated. Peak concentrations of ramiprilat in plasma (8.7 +/- 1.6 ng/ml) were reached after about 8 hours. AUC0-8 and AUC0-24-values were 36.5 and 111.9 ng.h/ml, respectively. Ramiprilat Cmax-concentrations were about 300-fold higher in bile than in plasma, the corresponding difference for ramipril between bile and plasma was about 4-fold. The main fractions excreted in the urine were diketopiperazine acid and ramiprilat amounting to 13.2 +/- 5.6 and 4.4 +/- 2.4%, respectively, of the dose administered. Only a very small fraction of the dose was excreted with urine as unchanged ramipril, on average 0.9 +/- 1.0%. The main fractions excreted in the bile were diketopiperazine acid, ramiprilat glucuronide and diketopiperazine, 9.0 +/- 5.3, 3.4 +/- 4.2 and 2.0 +/- 1.2% in 24 hours, respectively, of the dose administered. Only a negligible fraction of the dose (average 0.1 +/- 0.1%) was excreted with bile as unchanged ramipril. In conclusion, there is strong evidence that circulating ramipril and ramiprilat are eliminated by both the liver and the kidneys. For the patients studied it can be estimated from late collection periods that some 2/3 of circulating ramipril and ramiprilat are eliminated by the kidneys and 1/3 eliminated by the liver.
Administration, Oral↗
An interlaboratory comparison of the FDA protocol for the evaluation of cavitation potential of mechanical heart valves.
Five laboratories carried out measurements of cavitation threshold for a common set of six mechanical prosthetic heart valves, two each from three different manufacturers. This study was intended to evaluate to what extent FDA's current guidance for cavitation testing would lead to consistent results in a variety of laboratory settings and to seek areas for improvement in the recommended test protocol. The inter-laboratory study protocol specified: (1) characterization of the test fluid by oxygen content and electrical conductivity, (2) location and frequency response of pressure sensors, (3) determination of ventricular and atrial pressures (P) and loading rates (dP/dt) averaged over the time period of valve closure and over the time periods of 1 ms, 5 ms, and 20 ms prior to video visualization. The protocol did not specify: (1) the fluid pumping equipment to be used to generate cavitation, (2) the pump or fluid parameters adjusted to raise or lower the loading rate, (3) the equipment, technique, or sensitivity used to visualize cavitation, and (4) a specific definition of the threshold for cavitation. Results from the five laboratories are reported. Significant differences in results were observed in dP/dt and in the pressure difference across the valves during closure at cavitation threshold. Specific differences in test systems included a wide range of ventricular compliance and single valved versus double valved test systems. Three single valve systems with compliant ventricles produced results in reasonable agreement with one another. Further similarity in test equipment should be specified to assure adequate interlaboratory reliability for cavitation testing. Areas needing better specification include the design of the valve mount, the design of the cavitation generators, and qualitative criteria for detection of threshold cavitation.
Biocompatible Materials↗
Preliminary results of biliary excretion of ramipril after T-drainage in cholecystectomy patients.
Four cholecystectomy patients, aged between 52 and 56 years, weighing between 64 and 90 kg, received 5 mg of ramipril as a single dose in order to investigate the pharmacokinetics and excretion pattern of ramipril. All patients had a T-drainage that allowed bile collection. Serum was collected at regular intervals, bile was collected hourly for 6 h followed by a 6- and 12-h fraction, and urine was collected every 2 h for 8 h followed by a 4- and 12-h fraction. The concentrations of ramipril and ramiprilat in serum and ramipril, ramiprilat, ramipril glucuronide, ramiprilat glucuronide, diketopiperazine, and diketopiperazine acid in bile and urine were determined and the amounts excreted in urine and bile over 24 h were calculated. There were great interindividual differences in maximum concentrations as well as in the time to reach maximum concentrations in plasma and bile as well as in the excretion pattern between urine and bile. The highest concentrations in bile were found for diketopiperazine acid (3,080 ng/ml) and ramipril glucuronide (2,414 ng/ml). In general, only minimal amounts of unchanged ramipril (prodrug) were detected in the bile. In the urine, the major metabolites excreted were diketopiperazine acid, ramiprilat, and diketopiperazine in amounts of 537, 188, and 124 micrograms, respectively. In bile, the main substances excreted were diketopiperazine acid and ramiprilat glucuronide, which amounted to 501 and 314 micrograms, respectively. Biliary excretion may be the explanation for the noncomplete urinary recovery of ramipril and its metabolites.
Angiotensin-Converting Enzyme Inhibitors↗
[100 malar fractures].
Fractures of the malar are treated by therapeutic methods which are simple to put into operation and very effective based on osteosynthesis, screw-in plates, grafts and, in particular, the well-tolerated silicone implants (54 cases without any signs of rejection). The 100 case histories show our successes and failures.
Humans↗