In vitro generation of differentiated cardiac myofibers on micropatterned laminin surfaces

Cardiac muscle fibers consist of highly aligned cardiomyocytes containing myofibrils oriented parallel to the fiber axis, and successive cardiomyocytes are interconnected at their ends through specialized junctional complexes (intercalated disks). Cell culture studies of cardiac myofibrils and intercalated disks are complicated by the fact that cardiomyocytes become extremely flattened and exhibit disorganized myofibrils and diffuse intercellular junctions with neighboring cells. In this study we sought to direct the organization of cultured cardiomyocytes to more closely resemble that found in vivo. Lanes of laminin 5-50 microm wide were microcontact-printed onto nonadhesive (BSA-coated) surfaces. Adherent cardiomyocytes responded to the spatial constraints by forming elongated, rod-shaped cells whose myofibrils aligned parallel to the laminin lanes. Patterned cardiomyocytes displayed a striking, bipolar localization of the junction molecules N-cadherin and connexin43 that ultrastructurally resembled intercalated disks. When laminin lanes were widely spaced, each lane of cardiomyocytes beat independently, but with narrow-spacing cells bridged between lanes, yielding aligned fields of synchronously beating cardiomyocytes. Similar cardiomyocyte patterns were achieved on the biodegradable polymer PLGA, suggesting that patterned cardiomyocytes could be used in myocardial tissue engineering. Such highly patterned cultures could be used in cell biology and physiology studies, which require accurate reproduction of native myocardial architecture.     

Absence of circulating microemboli in patients with atrial fibrillation undergoing electric cardioversion

Electrical cardioversion (CV) of atrial fibrillation (AF) is associated with an increased risk of stroke, and its appropriate prevention is still a matter of debate. It is known that, besides dislodgement of pre-existing intra-atrial thrombi, the "stunned" atrium after CV is an important cause of thrombus formation and subsequent embolism. We investigated whether CV of AF is associated with occurrence of circulating microemboli (ME) representing a sensitive marker of the actual thromboembolic activity. Twenty-nine patients (22 men) aged 54 +/- 13 years suffering from valvular (n = 5) or nonvalvular (n = 24) AF were studied. All but 1 patient (with recent-onset AF) had been put on oral anticoagulation (INR >2.0) for at least 3 weeks before and 4 weeks after successful CV. In all patients, exclusion of internal carotid artery stenosis and atrial thrombus was performed prior to CV. Five unilateral 1-hour transcranial Doppler ME monitorings over the middle cerebral artery were performed (1) before CV, and (2) immediately, (3) 4-6 h, (4) 24 h, and (5) 2-4 weeks after CV. Total absence of circulating ME was found before CV as well as during a cumulative monitoring time of 115 h after successful CV. Electrical CV of AF after at least 3 weeks of effective anticoagulation is not associated with occurrence of cerebral circulating ME. This finding requires further investigation including high-risk patients with AF undergoing CV based on different treatment protocols.     

Evaluation of the fungicide manganese-zinc ethylene bis(dithiocarbamate) (mancozeb) for sublethal and acute toxicity to Eisenia fetida (Oligochaeta)

This article describes the outcome of laboratory experiments to determine the acute and sublethal effects of the fungicide mancozeb on the earthworm Eisenia fetida. Apart from a standardized acute test, young worms, 25 days old, were exposed to mancozeb mixed into a urine-free cattle manure substrate. Five groups of 10 worms each were used per concentration level (0, 8, 44 mg/kg substrate). The following life-history parameters were measured: growth in consecutive weeks over a 6-week period, survival rate, maturation time, cocoon production, hatching success of cocoons, number of hatchlings per cocoon, and incubation time of cocoons over another 4 weeks. The results indicated that mancozeb had no significant detrimental effect on either growth or reproduction of E. fetida at the recommended dose (8 mg/kg) or at an estimated environmental concentration (44 mg/kg). The findings do not support the hypothesis that avoidance response to mancozeb could serve as an indication of toxicity.     

Social Problem Solving, Mood, and Suicidality Among Inpatient Adolescents

Relationships between social problem solving, mood, and suicidality were examined in a sample of 105 adolescent psychiatric inpatients (ages 12–18). Youth were administered the Social Problem-Solving Inventory—Revised (T. D'Zurilla & A. Maydeu-Olivares, 1995) as well as standardized self-report and interview measures of dysphoria, hopelessness, anxiety, and suicidality. Results indicated that a negative problem orientation as well as an avoidant or impulsive problem-solving style were associated with less favorable scores on all of the latter measures, including greater reported suicidality. By contrast, associations were not observed between utilization of rational problem-solving skills and measures of either mood or suicidality. Structural equation modeling analyses revealed that the relationships found between the former measures of social problem solving and suicidality were mediated by more direct associations of less-effective social problem solving with both dysphoria/state-depression and hopelessness.     

Solitäre vielkammerige Cyste der Niere

Ohne ZusammenfassungMit 6 Textabbildungen.     

Adrenoleukodystrophy in a mother and son.

A 6 year old boy died from a degenerative brain disease which was clinically and pathologically typical of adrenoleukodystrophy. Shortly before his disease became manifest his 28 year old mother had presented with similar symptoms, and subsequently died. Her brain showed almost identical features including the presence of pathognomonic ultrastructural inclusions. The accumulation of very long chain fatty acids in cerebral white matter as well as high hexacosanoic to docosanoic acid (C26:22) ratios, substantiated the diagnosis in both cases. This is one of the few documented cases of adrenoleukodystrophy in an adult female, and is almost certainly an example of clinical manifestation of this X-linked inherited disease in a carrier.     

Thermoacoustic computed tomography--technical considerations.

We have constructed a thermoacoustic computed tomography scanner for imaging soft tissue in the human body. Thermoacoustic signals are induced in soft tissue by irradiation with 434 MHz rf energy. The thermoacoustic signals are detected by an array of transducers mounted on a hemispherical bowl. A three-dimensional, filtered backprojection algorithm is used to reconstruct rf absorption patterns within soft tissue. We have demonstrated soft tissue differentiation sufficient to delineate the normal internal structures of an excised lamb kidney using safe levels of rf radiation.