Polymerase chain reaction amplification as a diagnostic tool in culture-negative multiple-valve endocarditis

We report a case of culture-negative infectious endocarditis in a 17-year-old boy in which the etiologic diagnosis could only be provided by polymerase chain reaction amplification and sequencing of the bacterial 16S rRNA gene from valve tissue.     

Mortality and complications after stoma closure

HYPOTHESIS: This study was undertaken to evaluate factors contributing to hospital mortality and complications of stoma closure. DESIGN: Retrospective cohort study. SETTING: Department of Surgery of a 2500-bed university hospital. PATIENTS: Consecutive eligible patients who underwent stoma closure were selected from a local registry containing 30 219 patients. The medical records of 587 adult patients were reviewed according to a predefined extraction form. Patients with additional, unrelated surgical interventions or younger than 18 years were excluded. Follow-up was complete for all included patients. MAIN OUTCOME MEASURES: The primary outcome variable was 30-day mortality; the secondary outcome variable was presence of surgery-related complications within 30 days. RESULTS: We analyzed 533 patients with stoma closure between 1993 and 2001. The overall stoma closure-related mortality rate was 3% (15 patients); the overall stoma closure-related surgical complications rate was 20% (107 patients). Wound infections (9%) and anastomotic leakage (5%) were the most common surgical complications. Age was the only significant risk factor for survival (P = .02). Use of a soft silicone drain for intraperitoneal drainage (odds ratio, 1.62 [95% confidence interval, 1.07-2.45]; P = .03) was the only significant risk factor for complications. In patients with carcinoma as the primary disease (odds ratio, 0.61 [95% confidence interval, 0.40 to 0.93]; P = .02), we observed significantly fewer complications. CONCLUSIONS: We found considerable mortality and complications after stoma closure. Apart from age, we could not identify any predictor for mortality in patients with stoma closure. Randomized studies are needed to determine whether certain types of drains influence outcome.     

Mechanical stretch induces podocyte hypertrophy in vitro

BACKGROUND: Increased intraglomerular pressure is a final pathway toward glomerulosclerosis in systemic hypertension, diabetes, and focal segmental glomerulosclerosis (FSGS). Increased intraglomerular pressure causes stress-tension, or stretch, on resident glomerular cells. However, the effects of stretch on podocyte growth, and the mechanisms that underlie this, have not been elucidated. METHODS: To test the hypothesis that stretch alters podocyte growth, cultured mouse podocytes were exposed to cyclic mechanical stretch created by vacuum; control cells were grown under similar conditions, but not exposed to stretch. Proliferation (cell cycle phases) and hypertrophy (forward light scatter) were measured in stretched and control podocytes by flow cytometry. The role of the cyclin-dependent kinase (CDK) inhibitors, p21 and p27, was examined by stretching podocytes isolated from p21 and p27 knockout (-/-) mice, and the role of specific signaling pathways was assessed by Western blot analysis and blocking studies. RESULTS: Our results showed that stretch reduced cell cycle progression in wild-type and single p27-/- podocytes and induced hypertrophy in these cells in all phases of the cell cycle at 24, 48, and 72 hours. In contrast, stretch did not induce hypertrophy in single p21-/- and double p21/p27-/- podocytes. Stretch-induced hypertrophy required cell cycle entry, and was prevented by specifically blocking extracellular signal-regulated kinase 1/2 (Erk1/2) or Akt. Although stretch increased p38 activation, inhibition of this pathway had no effect on hypertrophy. CONCLUSION: Mechanical stretch induces hypertrophy in podocytes in vitro in all phases of the cell cycle. This effect is cell cycle dependent, and requires p21, Erk1/2, and Akt. Stretch may play a role in podocyte injury when intraglomerular pressure is increased.     

Diffusions-Tensor-Bildgebung (DTI) bei Patienten im apallischen Syndrom

Zusammenfassung Hintergrund und Ziel: Die Diagnostik des apallischen Syndroms beschränkte sich bisher auf die klinische Untersuchung und Zusatzuntersuchungen mittels EEG und evozierter Potentiale. Die Bildgebung spielte bei der Diagnosesicherung keine Rolle. Mit der Diffusions-Tensor-Bildgebung (DTI) sollte versucht werden, den Defektbereich im Hirnstamm zu visualisieren. Patienten und Methodik: Sieben Patienten im apallischen Syndrom nach Schädel-Hirn-Trauma (SHT) wurden in einem 1,5-Tesla-MRT-Gerät (INTERA, Fa. Philips) mit koronaren diffusionsgewichteten Spinechosequenzen untersucht. Es wurden sechs nicht kolineare Gradientenanregungen entlang den kortikospinalen Bahnsystemen verwendet. Die Untersuchung fand im Mittel 6 Monate nach SHT statt. Die Rekonstruktion der Faserbahnen erfolgte mit einem IDL-basierten (Interactive Data Language; Research System Inc.) Fiber-Tracking-Tool. Im Defektbereich wurden des weiteren der ADC (apparent diffusion coefficient) und die FA (fraktionelle Anisotropie) bestimmt und mit einer Kontrollgruppe von 20 gesunden Probanden verglichen. Ergebnisse: Die Faserdarstellung zeigte bei allen Patienten eine Unterbrechung der kortikospinalen Bahnsysteme auf Höhe des Mesencephalons. Die ADC-Werte im Defektbereich waren im Vergleich zur Kontrollgruppe normal bis leicht erhöht. Die FA-Werte waren um fast 40% reduziert als Ausdruck einer Schädigung auf zellulärer Ebene. Patienten mit Kontrollen nach 5 Monaten zeigten atrophische Hirnstammveränderungen in Pons und Mesencephalon als morphologisches Korrelat einer Schädigung auf zellulärer Ebene. Schlussfolgerung: Mit Hilfe der DTI ist es erstmals gelungen, die Unterbrechung kortikospinaler Bahnsysteme bei apallischen Patienten zu visualisieren. Die FA-Werte können als Marker der Schädigung auf zellulärer Ebene angesehen werden und dürften für den Verlauf und die Verlaufsbeurteilung dieser Patientengruppe von Bedeutung sein.     

Renal epithelia in long term gradient culture for biomaterial testing and tissue engineering

In the organism epithelia perform perfect barrier functions. Strong rheological and mechanical influences constitute the normal environment of this tissue throughout life. Most epithelia are exposed to different fluids at the luminal and basal sides. To obtain realistic information about tissue development in modern biomaterial testing and tissue engineering it is necessary to mimick the natural environment of epithelia. Cultured cells are brought in contact with an artificial extracellular matrix to determine whether proper development into a functional epithelium occurs. As under natural conditions the cultures have to withstand mechanical and fluid stress over a prolonged period of time in close contact to a selected biomaterial. However, development of tissue-specific features such as polarization, tightness and transport under in vitro conditions will only occur, if the biomaterial and the culture conditions support tissue development. Leakage, edge damage and pressure differences during culture have to be avoided so that the natural functions of the growing epithelium can develop. Our aim is to generate functional epithelia derived from renal explants containing stem cells, which are microsurgically isolated and placed into specific O-ring carriers for optimal handling. The cells develop in combination with a collagenous matrix from an embryonic into a functional collecting duct (rCD) epithelium. To achieve optimal culture conditions the tissue is placed in a gradient culture container. A typical environment can be simulated by superfusing different culture media at the luminal and basal sides. Within days epithelia growing inside the gradient container build up a physiological barrier, which is maintained during the whole culture period. The described method allows to investigate the influence of new biomaterials over prolonged periods of time.     

TMT-induced autonomic and behavioral changes and the neural basis of its processing

One of the main interests in the field of neuroscience is the investigation of the neural basis of fear. During recent years, an increasing number of studies have used trimethylthiazoline (TMT), a component of red fox feces, as a stimulus to induce fear in predator naive rats, mice, and voles. The aim of the present review is to summarize these studies. We present an overview to the autonomic and behavioral changes that are induced by TMT exposure. Then, we summarize the small number of studies that have examined the neural processing of the TMT stimulus. Finally, we compare these studies with those using a natural predator or predator odor to induce fear and discuss the possible use of TMT exposure in rodents as an animal model of unconditioned fear in humans.