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Biomedical subjects

C Dent

Publications and source records attributed to C Dent.

At least 19 recordsLinked to original sources
PubMed2006

Urinary IL-18 is an early predictive biomarker of acute kidney injury after cardiac surgery.

Acute kidney injury (AKI) is a frequent complication of cardiopulmonary bypass (CPB). The lack of early biomarkers for AKI has impaired our ability to intervene in a timely manner. Urinary neutrophil gelatinase-associated lipocalin (NGAL) is recently demonstrated as an early biomarker of AKI after CPB, increasing 25-fold within 2 h and declining 6 h after surgery. In the present study, we tested whether interleukin-18 (IL-18) is a predictive biomarker for AKI in the same group of patients following CPB. Exclusion criteria included pre-existing renal insufficiency and nephrotoxin use. Serial urine samples were analyzed by enzyme-linked immunosorbent assay for IL-18 in 20 patients who developed AKI (defined as a 50% or greater increase in serum creatinine after CPB) and 35 controls (age, race, and gender-matched patients who did not develop AKI after CPB). Using serum creatinine, AKI was detected only 48-72 h after CPB. In contrast, urine IL-18 increased at 4-6 h after CPB, peaked at over 25-fold at 12 h, and remained markedly elevated up to 48 h after CPB. The performance of IL-18 as demonstrated by area under the receiver operating characteristics curve for diagnosis of AKI at 4, 12, and 24 h after CPB was 61, 75, and 73% respectively. Also, on multivariate analysis, both IL-18 and NGAL were independently associated with number of days in AKI among cases. Our results indicate that IL-18 is an early, predictive biomarker of AKI after CPB, and that NGAL and IL-18 are increased in tandem after CPB. The combination of these two biomarkers may allow for the reliable early diagnosis and prognosis of AKI at all times after CPB, much before the rise in serum creatinine.

Acute Kidney Injury↗
PubMed2006

The functional anatomy of Kager's fat pad in relation to retrocalcaneal problems and other hindfoot disorders.

Kager's fat pad is a mass of adipose tissue occupying Kager's triangle. By means of a combined magnetic resonance imaging, ultrasound, gross anatomical and histological study, we show that it has three regions that are closely related to the sides of the triangle. Thus, it has parts related to the Achilles and flexor hallucis longus (FHL) tendons and a wedge of fat adjacent to the calcaneus. The calcaneal wedge moves into the bursa during plantarflexion, as a consequence of both an upward displacement of the calcaneus relative to the wedge and a downward displacement of the wedge relative to the calcaneus. During dorsiflexion, the bursal wedge is retracted. The movements are promoted by the tapering shape of the bursal wedge and by its deep synovial infolds. Fibrous connections linking the fat to the Achilles tendon anchor and stabilize it proximally and thus contribute to the motility of its tip. We conclude that the three regions of Kager's fat pad have specialized functions: an FHL part which contributes to moving the bursal wedge during plantarflexion, an Achilles part which protects blood vessels entering this tendon, and a bursal wedge which we suggest minimizes pressure changes in the bursa. All three regions contribute to reducing the risk of tendon kinking and each may be implicated in heel pain syndromes.

Achilles Tendon↗
PubMed2004

Relation between access to tobacco and adolescent smoking.

OBJECTIVE: To examine the relation between rates of sales of tobacco to minors and youth smoking prevalence. DESIGN: Repeated annual cross sectional surveys. SETTING: Seventy five communities in Oregon. PARTICIPANTS: A random sample of students in grades 8 and 11 (ages 13 and 17 years) and retail outlets in each participating community. MAIN OUTCOME MEASURES: Thirty day and daily smoking prevalence. RESULTS: The rate of illegal merchant sales in the communities was related to the smoking rate for 11th graders in those communities, but not for 8th graders. For every 10% increase in illegal sales rates there was an estimated 0.8% increase in 11th grade 30 day smoking prevalence and a 0.4% increase in daily smoking. Communities with lower illegal merchant sales rates had expanded use of social sources and reduced use of commercial sources by 11th graders, with the opposite pattern seen in 8th graders. CONCLUSIONS: There appears to be a relatively small positive linear relation between the community rate of sales to minors and 11th grade youth smoking prevalence in those communities. Youth adjust their tobacco sources depending on the level of commercial availability.

Adolescent↗
PubMed2001

Early post-traumatic acute respiratory distress syndrome and albumin excretion rate: a prospective evaluation of a 'point-of care' predictive test.

All patients sustaining major trauma exhibit increased capillary permeability, manifested as micro-albuminuria. Urinary albumin excretion rate (AER) measured on intensive care units (ICU) can predict early post-traumatic acute respiratory distress syndrome (ARDS). This prospective study sought to evaluate AER as a practical predictive test for early ARDS. Staff at the participating centres were trained in the use of the Behring Turbitimer and the concept of AER as a predictor of early post-traumatic ARDS. AER was measured every 2 h for the first 24 h, on 54 adult blunt trauma admissions (ISS>/=18). A diagnosis of early acute lung injury (ALI) or ARDS was made using the American-European Consensus Conference criteria. Eleven patients developed ARDS, ten developed ALI, and 23 had no pulmonary dysfunction. The AER was significantly greater in those who developed ARDS 8 and 18 h after admission. The positive predictive value of the test was 64% at 8 h, the negative predictive power 73%. The test was performed most consistently in the middle 10 h of the study period. If intervention had been based on the 8 h data point result, 75% patients who had the test performed and later developed ARDS would have had intervention appropriately. In principle, testing for AER as a predictor of post-traumatic ARDS on ICU is feasible, however, this study has underlined the challenges of introducing new concepts into the ICU environment.

Albuminuria↗
PubMed2001

A novel approach to forensic investigation: three-dimensional kinematic and kinetic motion analysis.

Following a domestic incident, a five-year-old child was pronounced dead on arrival at hospital. The subsequent post-mortem examination found that the cause of death was peritonitis as a result of a rupture of the duodenum. During the police interview, the main suspect alleged that the injury occurred whilst playing a game which involved standing on the child's abdomen and chest. A reconstruction of the game was performed using 3-dimensional kinematic and kinetic motion analysis to investigate the feasibility of the statement as described by the defendant. Presented is a summary of the investigation together with a description of kinematic and kinetic methods employed.

Journal Article↗
PubMed2000

Observation on the recent examination of bones from St David's Cathedral.

Bones discovered in 1866 walled up in St David's Cathedral, West Wales were thought possibly to be those of St David and his companion St Justinian, both of whom died in the late 6th or early 7th century. Examination and radio carbon dating of the bones suggested that these were not from St David nor St Justinian. Some of the bones could be the remains of St Caradoc, a 12th century hermit. It is likely, however, that the bones are remains of clergy who, for reasons not yet understood, were re-interred into the wall.

Christianity↗
PubMed1999

Aggrecanase versus matrix metalloproteinases in the catabolism of the interglobular domain of aggrecan in vitro.

The importance of aggrecanase versus matrix metalloproteinase (MMP) enzymic activities in the degradation of aggrecan in normal and osteoarthritic (OA) articular cartilage in vitro was studied in order to further our understanding of the potential role of these two enzyme activities in aggrecan catabolism during the pathogenesis of cartilage degeneration. Porcine and bovine articular cartilage was maintained in explant culture for up to 20 days in the presence or absence of the catabolic stimuli retinoic acid, interleukin-1 or tumour necrosis factor-alpha. Release of proteoglycan from cartilage was measured as glycosaminoglycan (GAG) release using a colorimetric assay. Analysis of proteoglycan degradation products, both released into culture media and retained within the cartilage matrix, was performed by Western blotting using antibodies specific for the N- and C-terminal neoepitopes generated by aggrecanase- and MMP-related catabolism of the interglobular domain of the aggrecan core protein (IGD). In addition, studies determining the mRNA expression for MMP-3 and MMP-13 in these same cultures were undertaken. These analyses indicated that all three catabolic agents stimulated the release of >80% of the GAG from the articular cartilage over 4 days. The degree of GAG release corresponded to an increase in aggrecanase-generated aggrecan catabolites released into the media and retained within the cartilage. Importantly, there was no evidence for the release of MMP-generated aggrecan metabolites into the medium, nor the accumulation of MMP-generated catabolites within the tissue in these same cultures. Expression of the mRNAs for two MMPs known to be capable of degrading the aggrecan IGD, MMP-3 and MMP-13, was detected. However, increased expression of these MMPs was not correlated with aggrecan degradation. Analyses using porcine cartilage, cultured with or without catabolic stimulation for 12 h to 20 days, indicated that primary cleavage of the IGD by aggrecanase was responsible for release of aggrecan metabolites at both the early and late time points of culture. Cultures of late-stage OA human articular cartilage samples indicated that aggrecanase activity was upregulated in the absence of catabolic stimulation when compared with normal porcine or bovine cartilage. In addition, even in this late-stage degenerate cartilage, aggrecanase and not MMP activity was responsible for the release of the majority of aggrecan from the cartilage. This study demonstrates that the release of aggrecan from both normal and OA cartilage in response to catabolic stimulation in vitro involves a primary cleavage by aggrecanase and not MMPs.

Aggrecans↗
PubMed1995

Changes in glycosaminoglycan epitope levels in knee joint fluid following injury.

OBJECTIVE: To measure the levels of epitope on the chondroitin sulfate (CS) and keratan sulfate (KS) chains of proteoglycan fragments in synovial fluids from injured and contralateral uninjured knees of patients with traumatic cruciate ligament and/or meniscus damage. METHODS: Enzyme-linked immunosorbent assays were used to determine the levels of monoclonal antibody epitopes 3-B-3 and 7-D-4 (CS), and 5-D-4 (KS), in paired joint fluids from the injured and uninjured knees of trauma patients. RESULTS: Levels of the CS epitopes were increased in the trauma joint fluids from most patients, with higher levels of 3-B-3 epitope in 12 of the 16 patients, but the difference did not achieve significance; however, 7-D-4 levels were higher in 15 patients, and the difference was highly significant (P = 0.0005). In contrast, the KS epitope detected by 5-D-4 was decreased in 13 of 15 patients, and the difference was significant (P = 0.0074). CONCLUSION: The increased level of 7-D-4 epitope on proteoglycans in joint fluid from injured knees may reflect the response of the articular cartilage to acute trauma resulting in altered expression of specific CS epitopes on cartilage proteoglycans. The fall in KS epitope levels may reflect the synthesis of proteoglycans that have lower KS content.

Antibodies, Monoclonal↗
PubMed1995

The television, school, and family smoking prevention and cessation project. VIII. Student outcomes and mediating variables.

BACKGROUND: This paper presents the student outcomes of a large-scale, social-influences-based, school and media-based tobacco use prevention and cessation project in Southern California. METHODS: The study provided an experimental comparison of classroom delivery with television delivery and the combination of the two in a 2 x 2 plus 1 design. Schools were randomly assigned to conditions. Control groups included "treatment as usual" and an "attention control" with the same outcome expectancies as the treatment conditions. Students were surveyed twice in grade 7 and once in each of grades 8 and 9. The interventions occurred during grade 7. RESULTS: We observed significant effects on mediating variables such as knowledge and prevalence estimates, and coping effort. The knowledge and prevalence estimates effects decayed partially but remained significant up to a 2-year follow-up. The coping effort effect did not persist at follow-ups. There were significant main effects of both classroom training and TV programming on knowledge and prevalence estimates and significant interactions of classroom and TV programming on knowledge (negative), disapproval of parental smoking, and coping effort. There were no consistent program effects on refusal/self-efficacy, smoking intentions, or behavior. CONCLUSIONS: Previous reports demonstrated successful development and pilot testing of program components and measures and high acceptance of the program by students and parents. The lack of behavioral effects may have been the result of imperfect program implementation or low base rates of intentions and behavior.

Child↗
PubMed1990

Visual and verbal metaphors: developmental interactions.

This study investigated developmental changes in children's abilities to comprehend visual metaphors as measured by their use of verbal metaphor. The visual metaphors were compound objects, e.g., a top with features of a ballerina (head and skirt). 30 participants at each of 4 ages--5, 7, 10, and adult--described objects ordered in pairs; half described standard objects and the other half corresponding compound objects (half stationary, and half moving, e.g., spinning). Total metaphoric descriptions reached the adult frequency by age 7 for compound objects, but increased from 5 to 10 to adult for standard objects. For all but the youngest children, moving objects were more likely to be described using action vehicles. These results indicate that from 5 to 7 children improve in the ability to understand visual metaphors, which display topic-vehicle interaction; from 5 through 10 to adulthood they improve in the ability to comprehend metaphoric similarity.

Adult↗
PubMed1989

Substance use among eighth-grade students who take care of themselves after school.

This investigation focused on substance use among children who regularly care for themselves after school (latchkey children). The data, collected from 4932 eighth-grade students, indicated that self-care is an important risk factor for alcohol, tobacco, and marijuana use. Data collected from 2185 parents validated these findings. Eighth-grade students, who took care of themselves for 11 or more hours a week, were at twice the risk of substance use as those who did not take care of themselves at all. This relationship held at all levels of sociodemographic status, extracurricular activities, sources of social influence, and stress. Of the 186 stratified tests of the relationship, 90% were significant; even those not found to be significant were in the direction expected. Path analyses suggest that risk-taking, having friends who smoke, and being offered cigarettes may partially explain the relationship between self-care and substance use. Those eighth-grade students who select friends who smoke and place themselves in situations in which they are offered cigarettes may be manifesting a desire to display their sense of maturity and independence. The fact that the increase in substance use occurred among almost all strata tested and the fact that mediation was not complete suggest that more than one mechanism may account for the associated increase in substance use. It is also possible that more time in self-care results in more unnoticed solitary trials of substances, as well as trials motivated by peer offers or peer pressure to use substances.

Adolescent↗
PubMed1975

Rate of incorporation of dietary fat in gold thioglucose obesity in mice.

Gold Thioglucose injections in mice are followed by a rapid accumulation of fat in the carcasses. The incorporation of an oral dose of [3H] glyceroyl tripalmitate in body fat stores showed after GTG-treatment a transient but significant increase and a return to normal values within 6 weeks. The rate of incorporation of dietary fat into the body was estimated from these values as well as from food intake and fat content of the diet (2.5 per cent). The resulting curve showed great similarity with the first differential of the curve of total body fat accumulated during that period. The rate of incorporation of dietary fat into body stores is apparently modified in GTG obesity in mice.

Adipose Tissue↗