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Biomedical subjects

C J Young

Publications and source records attributed to C J Young.

16 recordsLinked to original sources
PubMed1995

Pretransplant status and patient survival following liver transplantation.

The current liver allocation system has been criticized, since available organs go to those who are the most critically ill. These recipients have the poorest overall survival. Identification of pretransplant risk factors for mortality would allow better allocation of donor livers. This study was a retrospective analysis of pretransplant clinical and laboratory parameters and subsequent postoperative liver transplant mortality to identify high-risk subgroups. Of 347 consecutive consecutive primary liver transplant recipients, 59 (17%) met United Network for Organ Sharing (UNOS) criteria for status 4. Pretransplant factors included liver function, coagulation, albumin and ammonia levels, renal function, the presence of ascites, and etiology of liver disease. Overall 1-year patient survival was significantly worse for the status 4 recipients (89.0% vs. 67.7%; P = 0.01). In a univariate analysis of pretransplant risk factors for all recipients, elevated creatinine (P = 0.008) and ammonia (P = 0.009), and UNOS status 4 (P = 0.01) significantly affected postoperative survival. In multivariate analysis of pretransplant risk factors for all recipients, elevated creatinine (P = 0.003) was the only factor to significantly affect postoperative survival. In UNOS status 4 patients, univariate analysis of pretransplant risk factors and their influence on patient survival demonstrated that prolonged coagulation partial thromboplastin time (P = 0.04) and a higher grade of encephalopathy (P = 0.02) significantly affected postoperative survival. Advanced encephalopathy (P = 0.009) and prolonged partial thromboplastin time (P = 0.01) were the only significant risk factors by multivariate analysis in status 4 patients. In status 4 and non-status 4 patients, we identified risk factors that adversely affected patient survival, but their predictive power was insufficient to deny transplantation. Despite the higher mortality in status 4 recipients, their long-term survival is only slightly worse than that of non-status 4 patients. Until better predictors of survival are ascertained, our data do not support limiting the use of donor livers in UNOS status 4 recipients.

Adult↗
PubMed1995

Retrograde-delivered cardioplegia is not distributed equally to the right ventricular free wall and septum.

Right ventricular myocardial protection during cardiac surgery continues to be a challenge. Retrograde delivery of cardioplegia has been shown to perfuse left ventricular regions subtended by critical coronary stenosis and not adequately protected by antegrade delivery. However, the distribution of cardioplegia from the coronary sinus to the right ventricle remains in question. A reliable means for assessing such flow distribution intraoperatively is provided by contrast echocardiography. It was hypothesized that conventional use of coronary sinus catheters for retrograde cardioplegia delivery does not reliably perfuse the myocardial region subtended by the right coronary artery. Six patients scheduled to undergo elective coronary artery bypass surgery were evaluated with contrast echocardiography to determine the distribution of retrograde-delivered cardioplegia into the right ventricle. Sonicated Renografin-76 (Squibb Diagnostics, Princeton, NJ) was injected during retrograde delivery of cold crystalloid cardioplegia solution and continuous two-dimensional ultrasound imaging of the heart. On-line videodensitometric analysis was performed with a digital ultrasound system. The area under the curve and peak pixel intensity were determined for the anterior septum, the posterior septum, and the right ventricular free wall for each contrast injection. Recorded VHS videotape images of contrast-enhanced perfusion patterns were also reviewed and scored. On-line acoustic-densitometric analysis showed that right ventricular posterior and anterior septal peak pixel intensities were 4.8 +/- 3.2 and 7.3 +/- 1.5, respectively, compared with only 1.6 +/- 1.2 (p < or = 0.05) in the right ventricular free wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Proteinases released in vitro by the parasitic stages of Teladorsagia circumcincta, an ovine abomasal nematode.

Proteinases released during in vitro maintenance of third (L3) and fourth larval stage (L4) and adult Teladorsagia circumcincta (formerly Ostertagia circumcincta), an ovine abomasal nematode parasite, were characterized on the basis of pH optima, molecular size and specific proteinase inhibitor sensitivity. Enzyme activity was maximal at alkaline pH and stage-specific release was demonstrated. Proteinases released by the adult parasite degraded a variety of protein substrates including plasminogen, albumin and haemoglobin, in a pH-dependent manner. At alkaline pH fibrinogen degradation was restricted to the alpha and beta peptide chains although the gamma peptide chain was also degraded at acidic pH. Inhibitor sensitivity studies indicated that degradation was predominantly due to metalloproteinases although aspartyl proteinase activity was indicated at acidic pH.

Albumins↗
PubMed1992

Living with a heart transplant: long-term adjustment.

The number of heart transplants performed worldwide has increased greatly in the past 10 years, and survival rates will continue to improve with the introduction of new immunosuppressive therapies. With this improved lifespan outlook, the experience of living with a heart transplant needs to be understood as a chronic condition. Twenty-nine recipients who were a minimum of 5 months post-transplantation (mean 22 months) and 23 significant others were interviewed twice 6 months apart using close-ended and open-ended questions developed from the Common Sense Model of health beliefs. Results suggest that although life improved for the majority post-transplantation, recipients continue to experience work problems, financial burdens, family role changes, lifestyle changes, and side effects associated with long-term drug treatment.

Adaptation, Psychological↗
PubMed1990

Complete system control: an object-oriented approach.

This paper discusses some of the principles for complete system control for automated multiparameter haematology instruments. A method of analysing the control requirements is used, object-oriented flow diagramming, that combines concepts and notation from object-oriented programming with graphical flow diagramming to produce a model of a haematology instrument's reagent and sample flow during sample analysis. The model is used to analyse the control materials and control mechanisms for components, subsystems and the integrated system. The steps in the method are illustrated using two examples: the cyanmethaemoglobin method and the Coulter VCS leukocyte differential counter.

Hematology↗
PubMed1983

Enzyme polymorphism and the distribution of Trypanosoma congolense isolates.

Conditions were established for demonstrating, by electrophoresis, polymorphism in 12 soluble enzymes from Trypanosoma congolense. Three enzymes had identical mobilities in every stock, variation occurring among the remaining nine. Enzyme profiles were determined in 78 stocks collected from various hosts in a number of African countries, and were used by the computer to establish relationships within the collection. The major groupings formed solely from the isoenzymes corresponded remarkably closely to the origins of the stocks. Two distinct enzymic divisions formed, related only at the 20% level; Division A consisted entirely of stocks isolated in the humid coastal areas of West Africa, while Division B consisted mostly of stocks from drier zones throughout Africa. Some large groupings within these two main divisions also correlated with particular areas of origin within the major ecologic zones. The dry zone Division B included one group almost exclusively from East Africa, and two quite distinct enzymic groups from The Gambia; isolates from Liberia and Ivory Coast tended to fall into separate groups within the humid zone Division A. It is suggested that the differences between the major divisions may be associated with infraspecific adaptation to the different vector species occupying the separate habitats.

Africa↗
PubMed1982

Effects of cirrhosis and ageing on the elimination and bioavailability of ranitidine.

The plasma concentrations of ranitidine after oral and intravenous administration have been measured in 10 healthy young adults, nine cirrhotic patients, and eight healthy elderly people. In the first of these bioavailability was 51 +/- 4% and half life 161 +/- 11 minutes after oral and 124 +/- 5 minutes after intravenous administration. In the cirrhotics bioavailability was increased to 70 +/- 7%, clearance was reduced, and there was a modest increase in half life. In the elderly bioavailability was similar to that in young adults, clearance was markedly reduced, and half life was prolonged to 241 +/- 7 minutes after oral and 194 +/- 11 minutes after intravenous administration. It is predicted that blood levels in cirrhotics and the elderly would be 50 to 60% higher than in healthy young adults after repeated oral administration of similar doses.

Administration, Oral↗
PubMed1980

Fructose in wild-caught Phlebotomus ariasi and the possible relevance of sugars taken by sandflies to the transmission of leishmaniasis.

Cold, acidified anthrone was used to test 200 wild-caught sandflies (Phlebotomus ariasi females) for the presence of fructose. This sugar, or others with a fructose moiety, were demonstrable in 157 (79%) of the flies; proportions of flies positive in different tests ranged from 44 to 91%. Higher proportions of flies gave positive results when tested less than one hour after capture than when kept in the laboratory for more than 12 hours before testing. Similarly high percentages of flies were positive in samples collected coming to engorge on dogs and in those caught in CDC miniature light traps. These results, together with published reports of the demonstration of sugars in 25 individually tested sandflies of other species confirm that, like other biting flies, sugar is an important part of the diet of sandflies. Natural sugars may influence the development of leishmaniae in sandflies and their subsequent transmission. The anthrone test was found to be simple, rapid and suitable for field use; it is a valuable addition to indirect techniques for the study of the behaviour of sandflies.

Animals↗
PubMed1980

Screening for hypertension in adolescents: the search for normal values.

Appropriate control of adult hypertension is currently challenging our health care system. Evaluation of juvenile hypertension may assist in alleviating this massive medical problem by helping to identify potentially remediable risk factors. Assessment of "normal" blood pressure values for children and adolescents must first be accomplished before attempting modification of "abnormals." A hypertension detection and referral surveyed the blood pressures of 7,498 New Orleans high school students aged 14 to 18, to identify youngsters with high blood pressure and to refer them for further evaluation; to demonstrate the range of adolescent blood pressures in this population; to stimulate cooperative blood pressure screening efforts; and to increase the awareness of hypertension and cardiovascular risk factors. Peer group analysis for age, sex, and race showed some variation and divergence to the "tracking" effect. Black boys, for example, showed a sharp increase in diastolic blood pressures at age 16. Blood pressures greater than the 90th percentile are recommended as criteria for referral for further medical evaluation, and were found in this study to be 140-150/84-90 mm Hg for boys and 130-140/84-90 mm Hg for girls.

Adolescent↗
PubMedDate not supplied

[Ecology of leishmaniasis in the south of France. 11. Canine leishmaniasis: successful experimental transmission from dog to dog by the bite of Phlebotomus ariasi Tonnoir, 1921 (author's transl)].

As part of a study of visceral leishmaniasis in the Cévennes in southern France, an infection was transmitted from dog to dog by the bite of a single sandfly, Phlebotomus ariasi Tonnoir, 1921. The role of this species as a vector, suspected from earlier studies, is, therefore, confirmed. Twenty female sandflies, which had engorged on a naturally infected dog 23 +/- 2 days previously were put with a healthy dog which, after an incubation period of 15 months, developed viscero-cutaneous leishmaniasis. In dissections of the sandflies immediately after contact with the experimental dog, it was found that only one had engorged. All of 17 sandflies dissected had midgut infections: 10 of these also had infections in the pharynx. The engorged specimen additionally had parasites in the proboscis, a condition thought by many workers to be necessary for the parasite to be transmitted by bite.

Animals↗
PubMedDate not supplied

[Ecology of leishmaniasis in the south of France. -- 12. Horizontal dispersion of Phlebotomus ariasi Tonnoir, 1921. Preliminary experiments (author's transl)].

By use of mark-release-recapture methods, evidence was obtained of the distance of the dispersion of Phlebotomus ariasi Tonnoir, 1021. Female flies, collected in a valley in the Cévennes mountains (at Roquedur, Gard), were marked with fluorescnt powders, released an then recaptured by searching with ultra-violet lamps. The majority of the flies recapture were among ones given a blood meal shortly before release. Recaptures were made from the second day after release. A number of females migrated with blood in the midgut; their ovaries were up to and including stage V. The distance between the extreme points of recapture was about 1 km, and the maximum recorded distance between points of release and recapture was 750 m. The epidemiological interest of these observations is that, at least in the Cévennes foci, the sandfly as well as the dog must now be considered as capable spreading the pathogenic agent of visceral leishmaniasis.

Animals↗