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David Marx

Publications and source records attributed to David Marx.

9 recordsLinked to original sources
PubMed2006

Incidence of Crohn disease in the Czech Republic in the years 1990 to 2001 and assessment of pediatric population with inflammatory bowel disease.

BACKGROUND: The aim of this study was to assess the pediatric population that suffered from inflammatory bowel disease (IBD) in the Czech Republic and to determine the incidence of Crohn disease (CD) in children up to 15 years age between 1990 and 2001. METHODS: Diagnostic criteria for CD, ulcerative colitis (UC), and indeterminate colitis (IC) were defined. Medical records provided a source of basic information about the children. A standardized protocol was filled out and sent to the coordinator of the study. All protocols were checked to see whether the data corresponded to the defined criteria and then were processed further. The study was retrospective in character for the years 1990 to 1999 and prospective for the years 2000 and 2001. RESULTS: Diagnostic criteria were met in 470 patients with IBD; 201 of them turned 18 years old during the study period. CD was diagnosed in 223 patients. The incidence of CD in children up to 15 years of age increased from 0.25/100,000 in 1990 to 1.25/100,000 in 2001. Eighty-two percent of children with CD were treated with aminosalicylates in combination with corticosteroids; 29% of patients received azathioprine. Severe growth retardation was recorded in 6.4% of adolescents with CD at the age of 18. UC was diagnosed in 202 patients. Therapy with aminosalicylates only was sufficient for control of the disease in 23% patients; 68% children were treated with corticosteroids, 15 of them (23% of the whole group) received additional azathioprine. Criteria for IC were met in 9.8% of all patients with IBD. CONCLUSION: This study confirmed an increase in incidence of CD in children younger than 15 years in the Czech Republic.

Adolescent↗
PubMed2004

Activation of p38 MAPK and increased glucose transport in chronic hibernating swine myocardium.

In preconditioned myocardium, activation of the mitogen-activated protein kinase (MAPK) p38 leads to increased glucose uptake via enhanced GLUT-4 translocation. Glucose uptake is also increased in chronic hibernating myocardium, but the role of p38 MAPK and GLUT-4 translocation has not been studied. Nine swine underwent instrumentation of the proximal left anterior descending coronary artery (LAD) with a small, external constrictor. At 3 mo after instrumentation, myocardial glucose uptake by PET imaging was higher in the LAD than in the remote region under basal, fasted conditions (0.08 +/- 0.02 vs. 0.04 +/- 0.01 micromol.min(-1).g(-1), P < 0.05). Compared with the remote region, the LAD region demonstrated increased membrane-bound GLUT-4 relative to total content (61 +/- 04 vs. 45 +/- 06%, P < 0.05), higher glycogen (28.37 +/- 4.41 vs. 19.26 +/- 1.87 mg/g wet wt, P < 0.05), and increased inducible nitric oxide synthase (NOS) activity (1.43 +/- 0.34 vs. 0.51 +/- 0.21 activity/mg protein, P < 0.05). p38 MAPK was 47 +/- 14% higher in the LAD than in the remote region (P < 0.05) and correlated well with the absolute degree of GLUT-4 membrane-bound translocation (r = 0.81, P < 0.01), relative increase in glycogen (r = 0.70, P < 0.05), and total NOS activity (r = 0.68, P < 0.05). In chronic hibernating myocardial tissue, p38 MAPK activation is increased under basal fasted conditions and correlates well with the increased degree of GLUT-4 translocation, glycogen accumulation, and NOS activity. As in preconditioned myocardium, activation of p38 MAPK may play an important role in the metabolic adaptations that characterize chronic hibernating myocardium.

Animals↗
PubMed2003

Incidence of flare-ups and evaluation of quality after retreatment of resorcinol-formaldehyde resin ("Russian Red Cement") endodontic therapy.

The purpose of this retrospective study was to evaluate the quality of treatment and incidence of flare-ups when teeth with resorcinol-formaldehyde resin are retreated in a postgraduate endodontic clinic. Fifty-eight cases were included in this study. Obturated and unfilled canal space was measured on radiographs. Forty-eight percent of the total canal space was filled before retreatment; 90% was filled after retreatment. After retreatment, obturations were rated as optimal in 59%, improved in 33%, unchanged in 6%, and worse in 2%. Seven patients (12%) had postretreatment flare-ups. Data were statistically analyzed using the Cochran-Armitage Test for Discrete Variables. No statistical difference in the incidence of flare-ups was found in teeth that before treatment had more than half the canal space filled compared to teeth with less than half, cases with pre-existing periradicular radiolucencies compared to cases with normal periradicular appearance, symptomatic cases compared to asymptomatic cases, or cases with optimal fillings after retreatment compared to less than optimal cases. It was concluded that teeth with resorcinol-formaldehyde fillings might be retreated with a good prognosis for improving the radiographic quality, but a higher than normal incidence of flare-ups may occur.

Acute Disease↗
PubMed2003

Repetitive supply-demand ischemia with dobutamine increases glucose uptake in postischemic and remote myocardium.

UNLABELLED: The goal of this study was to determine whether myocardial glucose uptake after repetitive ischemia differs in response to coronary occlusion-reperfusion versus supply-demand ischemia induced by dobutamine. Although glucose metabolism is increased after myocardial ischemia, the metabolic effect of supply-demand ischemia induced by dobutamine may increase glucose metabolism within remote myocardium. This would make it difficult to discriminate postischemic from remote myocardium with glucose tracers. METHODS: Eighteen swine with a hydraulic occluder and flow probe on the circumflex artery underwent repetitive ischemia. In group 1 (n = 9), the circumflex artery was occluded, whereas in group 2 (n = 9), circumflex flow was decreased by 30% before dobutamine (40 micro g/kg/min intravenously). Each pig underwent 15 min of ischemia, twice per day for 5 d. Echocardiography and PET to determine myocardial glucose ((18)F-FDG) uptake were performed after final ischemia, and tissue was later analyzed for activation of Akt, p38 mitogen-activated protein, and adenosine monophosphate (AMP) kinase. RESULTS: Wall thickening in the circumflex region was lower than in remote regions in both groups. (18)F-FDG uptake in the circumflex region was similar in groups 1 and 2 (0.22 +/- 0.03 and 0.23 +/- 0.04 micro mol/min/g, respectively; not statistically significant). In the remote region, (18)F-FDG uptake was lower than in the circumflex region in group 1 (0.14 +/- 0.03 micro mol/min/g; P < 0.05) but was similar to that in the circumflex region in group 2 (0.20 +/- 0.03 micro mol/min/g; not statistically significant). AMP kinase activity in the remote region was significantly lower than in the circumflex region in group 1 but was similar to that in the circumflex region in group 2. CONCLUSION: Unlike repetitive coronary artery occlusion-reperfusion, repetitive supply-demand ischemia with dobutamine alters glucose uptake within the remote myocardium, possibly as a result of AMP kinase activation. Clinically, these data suggest that (18)F-FDG studies have a limited role in discriminating postischemic from remote myocardium after dobutamine stress.

Animals↗
PubMed2002

Ischemic preconditioning prior to aortic cross-clamping protects high-energy phosphate levels, glucose uptake, and myocyte contractility.

BACKGROUND: We hypothesized that indices of myocyte contractility and metabolism could be preserved with ischemic preconditioning in a model of reversible ischemia similar to that occurring during routine cardiac surgery. Regional measures of metabolism and function have not been studied in conjunction with individual myocyte function during postischemic recovery of preconditioned myocardium. PATIENTS AND METHODS: In 16 dogs, myocardium supplied by the left anterior descending artery (LAD) was preconditioned with intermittent LAD ischemia and reperfusion. Following preconditioning, the heart was made globally ischemic for 20 min at normothermia by aortic cross-clamping while on cardiopulmonary bypass. In 10 animals, serial measurements of LAD and remote region adenosine triphosphate (ATP) levels, glucose uptake, and wall thickening were obtained with full-thickness drill biopsies, positron emission tomography (PET), and 2-D echocardiography, respectively. In the remaining 6 animals, cardiac myocytes were isolated after 1 h of reperfusion for measurement of myocyte contractility and intracellular calcium transients. RESULTS: ATP levels were higher in the preconditioned LAD region than in the remote region at end of ischemia (3.17 +/- 0.33 nmol/mg vs 2.59 +/- 0.30 nmol/mg, P = 0.006). Similarly, preconditioned region glucose uptake was 40% higher than remote region glucose uptake at 2 days postischemia (0.35 +/- 0.06 micromol/min/g vs 0.25 +/- 0.05 micromol/min/g, P = 0.019). There were no differences in regional wall thickening as measured by 2-D echo either immediately following ischemia or at 2 days. Individual myocyte contractile response to increasing concentrations of extracellular calcium was preserved in cells from preconditioned myocardium, but it was severely depressed in remote region myocytes. CONCLUSIONS: We conclude that regional ischemic preconditioning prior to prolonged ischemia protects myocardial glucose uptake and myocyte contractile function. The beneficial effects on glucose metabolism suggest that preconditioning may have sustained protective effects on cell metabolism.

Adenosine Triphosphate↗
PubMed2002

A field examination of two measures of work motivation as predictors of leaders' influence tactics.

The authors tested 2 motivation measures, the Motivation Sources Inventory (MSI; J. E. Barbuto & R. W. Scholl, 1998) and the Job Choice Decision-Making Exercise (A. M. Harrell & M. J. Stahl, 1981) as predictors of leaders' influence tactics. The authors sampled 219 leader-member dyads from a variety of organizations and communities throughout the central United States. Results strongly favored the MSI as a predictor of influence tactics. Limitations of the study include low power of relationships, sample size as limited by the research design, and education levels of participants. Future researchers should use larger and more diverse samples and test other relevant antecedents of leaders' behaviors.

Adult↗
PubMed2002

Glucose uptake and glycogen levels are increased in pig heart after repetitive ischemia.

Repetitive myocardial ischemia increases glucose uptake, but the effect on glycogen is unclear. Thirteen swine instrumented with a hydraulic occluder on the circumflex (Cx) artery underwent 10-min occlusions twice per day for 4 days. After 24 h postfinal ischemia and in the fasted state, echocardiogram and positron emission tomography imaging for blood flow ([(13)N]-ammonia) and 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) uptake were obtained. Tissue was then collected for ATP, creatine phosphate (CP), glycogen, and glucose transporter-4 content, and hexokinase activity. After reperfusion, regional function and CP-to-ATP ratios in the Cx and remote regions were similar. Despite the absence of stunning, the Cx region demonstrated higher glycogen levels (33 +/- 11 vs. 24 +/- 11 micromol/g; P < 0.05), and this increase correlated well with the increase in FDG uptake (r(2) = 0.78; P < 0.01). Hexokinase activity was also increased relative to remote regions (0.62 +/- 0.29 vs. 0.37 +/- 0.19 IU/g; P < 0.05), with no difference in GLUT-4 content. In summary, 24 h after repetitive ischemia, glucose uptake and glycogen levels are increased at a time that functional and bioenergetic markers of stunning have recovered. The significant correlation between glycogen content and FDG accumulation in the postischemic region suggests that increased rates of glucose transport and/or phosphorylation are linked to increased glycogen levels in hearts subjected to repetitive bouts of ischemia.

Adenosine Triphosphate↗
PubMedDate not supplied

Myocardial glucose uptake after dobutamine stress in chronic hibernating swine myocardium.

BACKGROUND: In patients with hibernating myocardium, regional uptake of the glucose analog 2-fluorine 18-fluoro-2-deoxy-d-glucose (FDG) is increased under resting conditions. It is unclear whether the degree of increased FDG uptake correlates with the degree of impaired blood flow response and whether chronic changes in the glucose transporters may play a role in the enhanced FDG uptake under fasted conditions. METHODS AND RESULTS: Twelve swine were instrumented with a constrictor on the left anterior descending (LAD) artery. Serial echocardiography and positron emission tomography studies were done to assess temporal changes in myocardial function, blood flow, and FDG uptake. One week after surgery (early study), wall thickening, blood flow, and postdobutamine FDG uptake in LAD and remote territories were similar. By approximately 6 weeks (late study), baseline wall thickening in the LAD region was lower than in remote regions (20% +/- 7% and 36% +/- 6%, P <.05), as was dobutamine-stimulated blood flow (0.92 +/- 0.16 mL. min(-1). g(-1) and 1.17 +/- 0.20 mL. min(-1). g(-1) in LAD and remote regions, respectively; P <.05). After the dobutamine infusion, FDG uptake in the LAD region during fasted conditions was higher than in remote regions (0.128 +/- 0.053 micromol. min(-1). g(-1) and 0.098 +/- 0.044 micromol. min(-1). g(-1), respectively; P <.05), and the increase was proportional to the impairment in dobutamine blood flow (r(2) = 0.62, P <.001). After the animals were killed, the LAD region showed a higher content of GLUT4 by immunoblots and a greater degree of translocation as estimated by immunohistochemistry. In 5 additional hibernating pigs studied under resting fasted conditions, FDG uptake and GLUT4 translocation were also higher in the LAD region, in the absence of dobutamine stimulation. CONCLUSIONS: In hibernating myocardium, regional FDG uptake under fasting conditions is higher than in remote regions, both at rest and after an infusion of dobutamine. The degree of poststress FDG uptake is proportional to the impaired stress-induced blood flow. Total GLUT4 content as well as membrane-bound protein is higher in the hibernating tissue, and these changes may facilitate the observed increase in FDG uptake.

Animals↗