Cytoplasmic localization of PML particles in laminopathies.

There is growing evidence that laminopathies, diseases associated with mutations in the LMNA gene, are caused by a combination of mechanical and gene regulatory distortions. Strikingly, there is a large variability in disease symptoms between individual patients carrying an identical LMNA mutation. This is why classical genetic screens for mutations appear to have limited predictive value for disease development. Recently, the widespread occurrence of repetitive nuclear ruptures has been described in fibroblast cultures from various laminopathy patients. Since this phenomenon was strongly correlated with disease severity, the identification of biomarkers that report on these rupture events could have diagnostic relevance. One such candidate marker is the PML nuclear body, a structure that is normally confined to the nuclear interior, but leaks out of the nucleus upon nuclear rupture. Here, we show that a variety of laminopathies shows the presence of these cytoplasmic PML particles (PML CPs), and that the amount of these protein aggregates increases with severity of the disease. In addition, between clinically healthy individuals, carrying LMNA mutations, significant differences can be found. Therefore, we postulate that detection of PML CPs in patient fibroblasts could become a valuable marker for diagnosis of disease development.

Disturbed nuclear orientation and cellular migration in A-type lamin deficient cells.

The nuclear lamina and the cytoskeleton form an integrated structure that warrants proper mechanical functioning of cells. We have studied the correlation between structural alterations and migrational behaviour in fibroblasts with and without A-type lamins. We show that loss of A-type lamins causes loss of emerin and nesprin-3 from the nuclear envelope, concurring with a disturbance in the connection between the nucleus and the cytoskeleton in A-type lamin-deficient (lmna -/-) cells. In these cells functional migration assays during in vitro wound healing revealed a delayed reorientation of the nucleus and the microtubule-organizing center during migration, as well as a loss of nuclear oscillatory rotation. These observations in fibroblasts isolated from lmna knockout mice were confirmed in a 3T3 cell line with stable reduction of lmna expression due to RNAi approach. Our results indicate that A-type lamins play a key role in maintaining directional movement governed by the cytoskeleton, and that the loss of these karyoskeletal proteins has important consequences for functioning of the cell as a mechanical entity.

Role of nuclear lamina-cytoskeleton interactions in the maintenance of cellular strength.

The response of individual cells to cellular stress is vital for cellular functioning. A large network of physically interconnected cellular components, starting from the structural components of the cells' nucleus, via cytoskeleton filaments to adhesion molecules and the extracellular matrix, constitutes an integrated matrix that functions as a scaffold allowing the cell to cope with mechanical stress. Next to a role in mechanical properties, this network also has a mechanotransductional function in the response to mechanical stress. This signaling route does not only regulate a rapid reorganization of structural components such as actin filaments, but also stimulates for example gene activation via NFkappaB and other transcription factors. The importance of an intact mechano-signaling network is illustrated by the physiological consequences of several genetic defects of cellular network components e.g. actin, dystrophin, desmin and lamins. These give rise to an impaired response of the affected cells to mechanical stress and often result in dystrophy of the affected tissue. Recently, the importance of the cell nucleus in cellular strength has been established. Several new interconnecting proteins, such as the nesprins that link the nuclear lamina to the cytoskeleton, have been identified. Furthermore, the function of nuclear lamins in determining cellular strength and nuclear stability was illustrated in lamin-knock-out cells. Absence of the A-type lamins or mutations in these structural components of the nuclear lamina lead to an impaired cellular response to mechanical stress and disturbances in cytoskeletal organization. In addition, laminopathies show clinical phenotypes comparable to those seen for diseases resulting from genetic defects in cytoskeletal components, further indicating that lamins play a central role in maintaining the mechanical properties of the cell.

[Simplified appendectomy without stump embedding. Experiences of 20 years conventional and 5 years laparoscopic application]. / Vereinfachte Appendektomie ohne Stumpfversenkung. Erfahrungen aus 20 jähriger konventioneller und 5jähriger laparoskopischer Anwendung.

Since 1975, the Department of Surgery in the Grevenbroich Community Hospital (Germany) has applied a simplified technique of open appendectomy. The inhouse modified procedure without stump embedding has been performed in 3,448 cases to date. The same approach has been used in 1,463 laparoscopic appendectomies since 1991. In the laparoscopic procedure the stump is ligated solely with Roeder's loop. None of the 4,911 patients who have undergone either open or laparoscopic appendectomy have developed stump inadequacy or stercoral fistulae. According to the special literature, the complication rate after appendectomies without stump embedding is lower than that after standard procedures. In retrospect, laparoscopic appendectomy with simple ligation has confirmed the results achieved with simple ligation in open appendectomies. The technique should therefore become more common practice in open appendectomies, as well.

[Indications for appendectomy using the so-called "3-day rule". 10 years' experiences]. / Die Indikation zur Appendektomie nach einer sogenannten "3-Tages-Regel". Erfahrungen aus 10 jähriger Anwendung.

Since January 1981, the so-called "3-day principle" in cases of suspected appendicitis has been applied in order to render the indications for surgery more precise. The retrospective analysis of a total of 1877 appendectomies performed between 1981 and 1990 demonstrated that the majority of histologically definite cases of acute appendicitis had been surgically treated on the day of admission to hospital. Furthermore, a second peak of histologically evident cases of acute appendicitis was seen with non-characteristic symptoms on the 3rd day. An additional remarkable finding was that 38.0% (!) of all appendices intraoperatively declared to be "innocent" showed histologically definite inflammatory alterations.

[Analgesia and sedation in neonatal-pediatric intensive care]. / Analgesie und Sedierung in der neonatologisch-pädiatrischen Intensivmedizin.

In pediatric intensive care, analgesia and sedation has become increasingly important for newborns as well as prematures in recent years. However, its importance is frequently not well recognized and sedation is confounded with analgesia. In our intensive-care unit (ICU), fentanyl and midazolam have proved to be useful. In newborn and premature infants, fentanyl alone has been sufficient because of its analgesic and sedative action. In a study on 20 newborns and prematures suffering from severe respiratory problems as compared with a historical group that did not receive fentanyl, we could show that in subjects receiving fentanyl, considerably less treatment with sedatives and other analgesics was necessary. Cardiopulmonary tolerance was satisfactory. The highest bilirubin values were reached about 1 day earlier and were slightly higher than those measured in the control group, but oral nutrition could be initiated sooner. In small infants, additional midazolam was given after cardiac surgery. During the first 72 h, we found a correlation between serum levels of midazolam and the depth of sedation; however, after 72 h of medication, the dose had to be raised because of an increase in metabolic clearance. During the concomitant administration of midazolam and fentanyl, significantly less midazolam was needed to achieve appropriate analog-sedation. Prior to the administration of analgesics and sedatives, care should be taken to ensure that circulatory conditions are stable and that there is no hypovolemia, and the drugs must be given slowly during several minutes. Especially in a pediatric ICU, light and noise should be diminished and contact between the parents and the child should be encouraged, even when the child is undergoing mechanical ventilation.

Analgesia and sedation in neonatal intensive care using fentanyl by continuous infusion.

To determine the effects of fentanyl in newborn and premature infants, we compared two groups of 20 newborn and premature babies under artificial ventilation for severe respiratory distress syndrome: a prospective group receiving fentanyl for analgesic and sedation and a historical control group, who did not receive fentanyl. Fentanyl serum levels during steady state were determined by radioimmunoassay. Average time of infusion was 86 +/- 47 h with a mean dosage of 0.68 +/- 0.24 micrograms/kg/h. The fentanyl group needed much less sedatives and catecholamines. Heart rate and blood pressure were not significantly changed by fentanyl. Meconium was excreted later, and higher values of bilirubin were reached earlier than in the control group. Although fentanyl proved to be helpful in the neonatal intensive care unit, the administration should remain under strict indication.