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Biomedical subjects

S Knipp

Publications and source records attributed to S Knipp.

7 recordsLinked to original sources

[Evaluation of myocardial viability with contrast-enhanced magnetic resonance imaging--comparison of the late enhancement technique with positronemission tomography].

PURPOSE: To compare contrast-enhanced magnetic resonance imaging (MRI) and positron emission tomography (PET) in the evaluation of myocardial viability. METHODS: [ (18)F]-FDG-PET, [ (201)Tl]-TlCl-SPECT and contrast-enhanced MRI were performed in 29 patients with proven coronary artery disease and impaired left ventricular function to assess myocardial viability. MRI scans were done on a 1.5 T scanner (Magnetom Sonata, Siemens, Germany). After the steady-state free precession cine study, 0.2 mmol/kg BW of Gd-DPTA (Magnevist(R), Schering, Germany) were administered i. v. For the detection of "late enhancement" (LE) indicating scar, left ventricular long axes and contiguous short axis slices of 8 mm thickness were scanned using an inversion recovery turbo gradient echo sequence (TR 8.0 ms; TE 4.0 ms; TI 180 - 240 ms; FA 20 degrees ). The evaluation of LE and FDG uptake in PET with perfusion defect in SPECT was done using an 8 (basal, mid) and 4 (apical) segment model in all short axes to cover the entire ventricle. The transmural extent of LE was assessed using a 4-point score system. Comparison between the two modalities was performed on a segmental basis. RESULTS: A total of 1753 segments were assessed. In MRI, 40 % of the segments showed myocardial scar, whereas PET revealed impaired uptake in 25 %. MRI obtained a very low interobserver variability in detecting myocardial scar (kappa 0.92). Using PET as the standard of reference in the segmental comparison, contrast-enhanced MRI yielded a sensitivity of 84 % and a specificity of 76 % for the detection of scar. 18 % of all segments showed LE but normal FDG uptake, 83 % of them referred to subendocardial scars. CONCLUSIONS: There is close agreement between contrast-enhanced MRI and PET in detecting transmural myocardial scars. Superior spatial resolution enables MRI to detect and quantify even subendocardial scar. Therefore, larger studies using functional recovery after revascularisation as an endpoint have to prove whether MRI might replace PET as the standard of reference in the assessment of myocardial viability.

Aged↗

Relapsing polychondritis in childhood--case report and short review.

Relapsing polychondritis (RP) is a disease of unknown etiology and it is characterized by inflammation of the cartilage. While the clinical picture of RP in adults is well described, RP in childhood is poorly documented. We describe a young girl presenting with acute dyspnea, stridor and polyarthritis. The diagnosis of RP was made 2 years after first presentation, when auricular chondritis occurred. Based on a MEDLINE search, reports on RP in childhood were reviewed. The frequency of chondritis and systemic manifestations of RP in children was compared to data in adults and found to be very similar. RP in childhood can be a life-threatening and debilitating disease.

Adult↗

Proliferation pattern changes in the zebrafish brain from embryonic through early postembryonic stages.

Proliferating cell nuclear antigen (PCNA)-immunohistochemistry was used for demonstrating the spatiotemporal course of proliferation in the brains of embryonic (24 h) through postembryonic (5 days) zebrafish (Danio rerio). Parallel series of the same stages prepared according to the combined Bodian fiber silver-stain/cresyl Nissl-stain were used for improved morphogenetic analysis (i.e., in detecting critical neuroanatomical landmarks). Starting from an essentially ubiquituous proliferation throughout the neural tube before 24 h, PCNA-immunoreactive cells become successively more restricted to a subset of gray matter cells around 48 h and even more distinct proliferation zones become apparent around 72 h. Both hindbrain and forebrain reveal a segmental organization with regard to the distribution of proliferation zones, but the rhombomeric pattern of PCNA-immunoreactive cells emerging between 48 h and 72 h precedes a similar prosomeric pattern by about 48 h. Two divisions of the midbrain-hindbrain boundary are described here morphologically and both are demonstrated to show sustained proliferation throughout the investigated time frame. In contrast, proliferation in the adjacent mesencephalic and cerebellar domains is rapidly down-regulated during the first 5 days of development.

Animals↗

Treatment-resistant expansion of CD8+CD28-cells in pediatric HIV infection.

There is a disease stage-dependent loss of CD28 expression on T cells in HIV-infected children. In this study, T cell recovery, in particular CD28 expression on T cells, was analyzed after initiation of highly active antiretroviral therapy in a group of eight mostly treatment-naive HIV-infected children. Plasma HIV-RNA levels were recorded, and numbers of CD4, CD8, CD4+CD28+, and CD8+CD28+ cells were determined by two-color flow cytometry. Values after 12 mo of therapy were compared with age-matched, seronegative control subjects. CD4 recovery to subnormal values was observed in all children. CD8+CD28+ cells recovered and were within the normal range after 12 mo of therapy (patients, 703 +/- 250 cells/microL; controls, 789 +/- 269 cells/microL), whereas CD8+CD28- cells (546 +/- 269 cells/microL) remained significantly expanded compared with age-matched controls (140 +/- 35 cells/microL). Expansions of CD8+CD28- cells persisted even in cases with long-term suppression of viral replication. Highly active antiretroviral therapy in HIV-infected children induces substantial but incomplete T cell recovery.

Adolescent↗

Gastric and duodenal features of meals mediate controls of liquid gastric emptying during fill in rhesus monkeys.

To study the dynamics of liquid gastric emptying in rhesus monkeys under conditions that simulated gastric fill during a meal, we measured the gastric emptying of liquid glucose at various concentrations and volumes when administered intragastrically at rates ranging from 12.5 to 37.5 ml/min. Glucose gastric emptying was faster during than following the period of gastric fill. At a single glucose concentration, volume infused rather than the rate of filling determined the volume emptied. Lower glucose concentrations emptied more slowly than physiological saline. As glucose concentration increased, emptying during fill slowed. Duodenal glucose infusions greatly slowed the rate of saline emptying during fill, demonstrating duodenal feedback control. Although casein hydrolosate emptied more rapidly than glucose, the dynamics of volume and concentration dependency and the role of duodenal feedback were similar. These data reveal that both gastric volume and duodenal negative feedback controls important in gastric emptying following stomach filling also contribute to its control during fill.

Animals↗

Endogenous CCK in the control of gastric emptying of glucose and maltose.

A role for endogenous cholecystokinin (CCK) in the control of gastric emptying of liquid glucose and maltose test meals in rhesus monkeys was assessed. Intragastric administration of a dose range (10-100 micrograms/kg) of the CCKA receptor antagonist devazepide produced a dose dependent acceleration of the emptying of 100 ml 300 mOsm test meals of glucose and maltose but had no effect on the emptying of a hyperosmotic (750 mOsm) NaCl solution. At the 100 micrograms/kg dose, the emptying of glucose and maltose meals were as rapid as the emptying of physiological NaCl. These data expand the demonstrated role of endogenous CCK in the slowing of gastric emptying of nutrients in rhesus monkeys to carbohydrates and suggest that previous negative results were due to the hyperosmotic nature of the glucose solutions.

Animals↗