Intramedullary pilocytic astrocytomas — a clinical and morphological study after combined surgical and photon or neutron therapy

Ten patients suffering from intramedullary pilocytic astrocytomas (WHO-classification: astrocytoma grade I) were investigated catamnesticly. Combined surgery and radiotherapy was performed. Seven patients received neutron irradiation postoperatively. In four cases the neurological symptoms were improved after follow-up periods ranging from 33 to 89 months. The three other patients died after 6 to 21 months. The autopsy findings of a 14 year old child are presented. Our results are compared with reports in the literature. In addition, long-term problems of the spinal column are discussed. It seems that the combined surgical and neutron therapy improves the prognosis of pencil gliomas.     

Stem cell research and cell transplantation for myocardial regeneration.

Several human organs are not capable of functional regeneration following a tissue defect and react with scar formation. In stem cell transplantation, undifferentiated or partly differentiated precursor cells are applied to defective tissue for therapeutic regeneration. After promising preclinical investigations, the transplantation of autologous stem cells for myocardial infarction treatment is being transferred to clinical use. Mesenchymal stem cells and endothelial precursor cells derived from the bone marrow or circulating blood as well as skeletal myoblasts are employed in clinical trials. Furthermore, indications for cell transplantation and delivery routes vary considerably throughout current investigations. Initial results suggest a potential for restoration of cardiac function in stem cell-treated patients; however, the mechanisms are not fully understood. This overview will focus on objectives, recent achievements, and future perspectives of diverse stem cell transplantation approaches.     

Genetics of fruit body production in higher basidiomycetes II. Monokaryotic and dikaryotic fruiting in schizophyllum commune

Summary In the wood destroying fungus Schizophyllum commune, a well known subject for genetic studies, fruit bodies are produced not only in the course of the sexual cycle but also asexually. Sexual fruiting requires the establishment of a dikaryon which is under the control of the incompatibility factors A and B. Asexual fruiting, however, starts directly from a monokaryon. The initiation of monokaryotic fruiting requires the presence of a single gene leading to the differentiation of fruit body initials. The action of at least two more genes is required for the further morphogenetic steps resulting eventually in the production of fruit bodies which differ in shape from dikaryotic fruit bodies. As a consequence of a mitosis their basidia produce two spores only. The three genes responsible for monokaryotic fruiting are pleiotropic and determine synergistically the timing of dikaryotic fruiting within a range between 6 to 20 d or longer. A fourth gene was found which codes epistatically for the formation of dome-like masses of stromatic tissue, thus directing morphogenesis into a side track.     

Long-term elevations of dietary sodium produce parallel increases in the renal excretion of urodilatin and sodium

The effects of dietary sodium intake on the renal excretion of urodilatin and of sodium were examined in six healthy male subjects. The 24-day study period was divided into three phases of 8 days each. Subjects Ingested 2.8 mequiv sodium (kg body weight)^–1 day^–1 during the first phase, 5.6 mequiv (kg body weight)^–1 day^–1 during the second phase, and 8.4 mequiv (kg body weight)^–1 day^–1 during the third phase. The excretion of both sodium (P<0.002) and urodilatin (P<0.006) increased in response to the increasing dietary sodium, while urine flow did not change. Urinary urodilatin excretion correlated closely with renal sodium excretion (P<0.001). Serum aldosterone levels (P<0.01) as well as serum renin levels (P<0.05) significantly decreased with increasing sodium intake. Plasma [Arg]vasopressin levels increased significantly (P<0.05). Plasma atrial natriuretic factor and cGMP levels as well as urinary cGMP excretion rates were unaltered by the changes in sodium intake. We conclude from these results that the renal natriuretic peptide, urodilatin, but not the main cardiac member of the natriuretic peptide family may be involved in the regulation of day-to-day sodium balance.     

Quantification and preservation of lectin binding by isolated cardiomyocytes

During preparation of cells for experimentation a considerable amount of bound substance is lost. Our aim was to develop a protocol which retained lectin binding to an extent similar to living cells. This procedure would use fixation procedures suited for fluorescent lectin conjugates and gold-conjugates to be visualized by light- and electron microscopy, respectively. We tested glutaraldehyde and paraformaldehyde in different concentrations before and after lectin binding, different buffers and divalent cations, as additives, to determine the effects on preservation of lectin binding. Lectin binding was visualized and semiquantitatively evaluated by image analysis in the light microscope after silver enhancement of lectin-gold conjugates and by using tetramethyl rhodaminyl isothiocyanate (TRITC)-conjugated lectins. Preservation of lectin binding was best visualized with fluorescent lectin conjugates, whereas during silver enhancement procedures of gold-conjugated lectins, a considerable amount of bound lectins was lost. In general, lectin binding to living cells followed by fixation is superior to fixation before lectin binding. Unfavourable combinations of fixatives and buffers can cause a loss of more than 90% bound lectin. In our experiments with freshly isolated guinea pig cardiomyocytes, lectin binding was best when we used Na-cacodylate buffer with glutaraldehyde fixation (0.1%) after binding of lectins to the living cells.     

Recombinant Kunitz protease inhibitory domain of the amyloid beta-protein precursor as an anticoagulant in venovenous extracorporeal circulation in rabbits

Investigations were performed to characterize a recombinant Kunitz protease inhibitory domain of the amyloid beta-protein precursor (rKPI) as anticoagulants. After a single intravenous infusion of wild type rKPI into dogs, its elimination fit a two compartment model with a t1/2alpha and t1/2beta of 5 and 77 min, respectively. Further investigations determined if a variant form of rKPI with 178-fold more potent anti-factor Xa activity (rKPI-DD135, Ki = 0.9 nM) could serve as an anticoagulant in a rabbit model of extracorporeal circulation using a venovenous shunt. A prospective investigation was initiated to compare standard heparin (n = 8) at 400 U/kg with different infusion concentrations of rKPI-DD135. After a single intravenous infusion of 1.89 mg/kg of rKPI-DD135 followed by a constant infusion at 0.003 (n = 3), 0.03 (n = 7), or 0.3 (n = 5) mg/kg/min, the anti-factor Xa activity of the animals' plasma rapidly reaches a steady state for the two lower infusion concentrations of the agent. All infusions of rKPI-DD135 prolong the activated clotting time with less variation than that seen with heparin administration. rKPI-DD135 anticoagulation does not prevent a drop in the platelet counts. Fibrinogen levels decrease only slightly when the circuit is anticoagulated with rKPI-DD135. rKPI-DD135 markedly prolongs the APTT, has little effect on the PT, and reduces plasma prekallikrein and plasminogen activation. The 0.3 mg/kg/min infusion concentration of rKPI-DD135 results in reduced deposition of 111Indium-labeled platelets on the circuit when compared to heparin. Last, after a steady state level is achieved, 60% of the plasma anti-factor Xa activity of rKPI-DD135 is eliminated within 60 min after stopping the infusion. These data show the rKPI-DD135 can provide single agent anticoagulation in a rabbit extracorporeal circuit. Development of short acting factor Xa inhibitors may be useful anticoagulants for cardiopulmonary bypass.     

First experience with gamma probe guided sentinel lymph node surgery in penile cancer

Because of the curative approach, the detection of lymph node metastases in squamous cell carcinoma (SCC) of the penis is of significant clinical relevance. Sentinel lymph node (SLN) identification by means of lymphangiography has been proven to be insufficiently safe. However, the high morbidity of inguinal lymphadenectomy and the considerable individual variability regarding the location of lymph node metastases justify the necessity of a technique that enables the identification of SLNs. Since 1998, SLNs have been intraoperatively identified and selectively dissected, after peritumoral injection of technetium-99m nanocolloid and using lymphoscintigraphy, in three patients (one with malignant melanoma and two with SCC). At least one SLN could be detected in each patient. The maximum surgical time was 30 min. There were no severe complications. Lymph node metastases did not occur in any patient. Upon a mean follow-up of 10 months, all patients are currently free of tumor. Owing to the long-term results of sentinel lymphadenectomy in malignant melanoma of other locations and our preliminary results with respect to penile carcinoma, we consider the current method appropriate as the only primary operation for lymph node staging in early stages and, in combination with modified inguinal lymphadenectomy, in locally advanced stages. Received: 24 November 1999 / Accepted: 21 April 2000     

Molecular weights of poly(butyl cyanoacrylate) nanoparticles determined by mass spectrometry and size exclusion chromatography

Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and size exclusion chromatography (SEC) were employed to elucidate the chemical composition, mean number average molecular weight (M_n), mean weight average molecular weight (M_w), and polydispersity (PD) of poly(butyl cyanoacrylate) (PBCA) manufactured by emulsion polymerisation. Both methods gave similar results for M_n, but substantial differences were observed for M_w and PD, with MALDI producing consistently lower values which could not be improved by off-line coupling of SEC and MALDI. MALDI gave a more detailed view on the chemical composition of the cyanoacrylate and revealed the presence of two additional polymer series with different end groups besides the expected PBCA series, which showed different retention in SEC. Their formation is explained by the secession/addition of formaldehyde from/to the regular polymer via (reverse) Knoevenagel reaction. In additional experiments, the influence of different pH on PBCA-NP during polymerisation was examined by comparison of polymerisation yield and particle diameter to their chemical composition as revealed by the MALDI spectra. The most uniform nanoparticles, with the highest polymerisation yield, narrowest particle size, and mass distribution were produced at pH 1.