Chemotherapy of fish parasites

There are few agents on the market that control fish parasites. These are substances that are mainly used in other hosts; due to the different metabolism of fish, they often have only moderate effects on fish parasites. Therefore, the research and development of fish-specific antiparasitic compounds is needed to avoid the high losses suffered by commercial fish hatcheries. Drugs similar to toltrazuril would perhaps be promising, due to their broad spectrum of efficacy.     

Die sogenannte Impfwut

Zusammenfassung Die im Verlaufe antirabischer Vaccinationen gelegentlich auftretenden paralytischen Komplikationen sind nicht virusbedingt, sondern die Folge einer Antigen-Antikörperreaktion nach Sensibilisierung mit dem organspezifischen Hirnantigen, das in den nicht ätherisierten Tollwutvaccinen enthalten ist. Diesbezüglich von einer Impfwut zu sprechen, erscheint nicht gerechtfertigt. Vielmehr sollte dieser Terminus für die postvaccinalen Komplikationen reserviert bleiben, bei denen der Ausbruch der Erkrankung in direktem Kausalzusammenhang zu dem in einer Vaccine enthaltenen lebenden Virus fixe steht.     

Eotaxin-2 alters eosinophil integrin function via mitogen-activated protein kinases

Adhesion molecules and chemokines contribute to selective eosinophil recruitment in allergic inflammation. In this study, we examined the effects of eotaxin-2, a CCR3-specific chemokine, on integrin-mediated eosinophil adhesion to vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), or both using a parallel plate flow system. Tissue culture plates were coated with various combinations of VCAM-1, ICAM-1, and/or eotaxin-2. Human eosinophils were infused at physiologic shear stress (0.5 dyn/cm(2)) for 10 min, and the numbers of attached eosinophils were monitored using video microscopy. Cells accumulated efficiently on VCAM-1 and even better on surfaces co-coated with VCAM-1 and ICAM-1, but poorly on surfaces coated with ICAM-1 or bovine serum albumin alone. When eotaxin-2 was co-immobilized with adhesion proteins, fewer cells adhered to VCAM-1 and more adhered to ICAM-1, whereas levels of attachment to VCAM-1 plus ICAM-1 showed no net change. However, experiments with adhesion molecule blocking monoclonal antibody showed that the contribution of ICAM-1-mediated adhesion was always greater if eotaxin-2 was present. Pretreatment of cells with a CCR3-blocking mAb, or PD98059, a MAP-kinase inhibitor, prevented the eotaxin-2-induced changes in eosinophil attachment. These data suggest that eotaxin-2, acting via MAP kinases, may facilitate eosinophil recruitment at sites of allergic inflammation by shifting their adhesion molecule usage away from VCAM-1-dominated to ICAM-1-dominated pathways.     

Human acute pancreatitis: Its pathogenesis in the light of immunocytochemical and ultrastructural findings in acinar cells

Summary Human acute pancreatitis results from an autodigestive process frequently associated with alcohol abuse, gall stone disease and shock. Peripancreatic fat necrosis was identified as one of the earliest visible lesions, whereas acinar cell necrosis and haemorrhage were regarded as secondary changes. To examine the alterations in acinar cells in more detail, their enzyme content and fine structural features were studied immunocytochemically using antisera against -amylase, lipase, trypsin, chymotrypsin and pancreatic stone protein, and electronmicroscopically in pancreatic tissues from patients with severe acute pancreatitis. Peripheral acinar cells in the immediate vicinity of fat necrosis were found to be heavily degranulated, while acinar cells at some distance of necrosis fully retained their enzyme content. Other frequent changes of the acinar cells included cuboidal transformation, loss of microvilli, increased occurrence of autophagosomes, and formation of enlarged acinar lumina. As there was no apparent cell membrane leakage or rupture of duct lumina, it is concluded that the acinar cells adjacent to fat necrosis release their granules by undirected basolateral extrusion. The findings thus suggest that one of the basic defects in acute pancreatitis is the uncontrolled release of enzymes from peripheral acinar cells into the interstitial space which, in turn, presumably by the action of lipase, leads to autodigestive fat necrosis.Dedicated to Prof. Dr. G. Seifert on the occasion of his 65th birthdayPresented in part at the Second International Symposium on the Classification of Pancreatitis, Marseille, 1984, and at the Meeting of the European Pancreatic Club, Manchester, 1985     

Veränderte Aktivitäten der Enzyme des Energiestoffwechsels in Thrombocyten von Patienten mit Lebercirrhose und Splenomegalie

Zusammenfassung 1. Die Aktivitäten von 28 Enzymen aus verschiedenen Abschnitten des Energiestoffwechsels wurden in isolierten Thrombocyten von 17 gesunden Menschen und 15 Patienten mit gesicherter Lebercirrhose gemessen.2. Die für Gewebe bekannte Proportionskonstanz der Enzymaktivitäten des zentralen Segmentes der Glykolyse (TIM, GAPDH, PGK, GPM und EN) findet sich auch in den Thrombocyten als Ordnungsprinzip. Die mitochondrial lokalisierten Enzyme NAD-spezifische Isocitratdehydrogenase und Glycerophosphatoxydase wurden erstmalig in Thrombocyten mit relativ hoher Aktivität nachgewiesen.3. Die Plättchen von Patienten mit Lebercirrhose und Milzvergrößerung infolge portaler Hypertension zeigten signifikant erhöhte Enzymaktivitäten in allen untersuchten Stoffwechselwegen, insbesondere der mitochondrial lokalisierten Enzyme. Funktionell bedeutsam erscheinen der ausgeprägte Anstieg der Mg⁺⁺-aktivierbaren ATPase, die gleichbleibende Aktivität der Fructose-6-Phosphatkinase und eine Verminderung der Lactatdehydrogenase. Bei der Patientengruppe mit Cirrhose ohne Milzvergrößerung lagen fast alle gemessenen Aktivitäten der Thrombocyten im Normbereich.4. Es wird ein Patient mit Lebercirrhose ohne Milzvergrößerung beschrieben, dessen Thrombocyten um den Faktor 8 höhere Aktivitäten fast aller gemessenen Enzyme aufwiesen. Auch in diesen Plättchen zeigte die Lactatdehydrogenase eine Aktivitätsverminderung gegenüber der Norm.5. Ein Enzymdefekt der Plättchen wie bei Thrombasthenie wurde bei Lebercirrhose nicht gefunden. Nach unseren Kenntnissen über die Enzymausstattung von Blutzellen handelt es sich bei den Thrombocyten mit höherer Enzymaktivität um eine jugendliche Zellpopulation. Die Pathogenese wird besonders hinsichtlich der Rolle der vergrößerten Milz diskutiert.

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Summary 1. The activities of 28 enzymes from different pathways of energy producing metabolism were measured in the isolated platelets of 17 normal persons and 15 patients with proven cirrhosis of the liver.2. In mammalian tissues a constant proportion between the enzymes of the central segment of the glycolytic pathway (TIM, GAPDH, PGK, GPM, EN) has been described. This constant proportion has been demonstrated also in the platelets. The mitochondrially localized enzymes NAD-specific Isocitratdehydrogenase and Glycerophosphatoxidase have been measured for the first time in platelets with a high activity.3. The platelets of patients with liver cirrhosis and splenomegaly following portal hypertension showed significant higher enzyme activities in all investigated pathways, mainly in the citric acid cycle. Functionally important could be the marked increase of the Mg⁺⁺ activated ATPase, the unaltered activity of the Phosphofructokinase and a lowered activity of the Lactatdehydrogenase in these platelets. The patients with cirrhosis but without a large spleen had normal enzyme activities of the platelets.4. One patient is described with cirrhosis without splenomegaly who had an elevation of nearly all measured enzymes by a factor 8 in his platelets. The LDH showed a decreased activity.5. No enzyme defect in the platelets of cirrhotic patients as in thrombasthenia was found. Basing on our knowledge of the enzyme equipment of blood cells the conclusion is drawn that the platelets with higher enzyme content represent a young cell population. The pathogenesis is discussed with special reference to the role of the enlarged spleen.

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Teilergebnisse wurden vorgetragen auf dem 2. Symposium der European Association for the Study of the Liver, Göteborg, 1967 und der 24. Tagung der Deutschen Gesellschaft für Verdauungs- und Stoffwechselkrankheiten, Hamburg 1967.     

Beitrag zur regionären Verteilung der Paraty-B-Phagentypen

Zusammenfassung Die Prüfung der Paraty-B-Phagentypen zeigt im Saarland einen hohen Anteil des in Deutschland seltenen Typs Dundee. Ein Vergleich mit den Phagentypen in Frankreich, insbesondere unter Berücksichtigung der departementalen Verteilung, legt es nahe, Über die zweifellos bestehenden engen Verkehrskontakte hinaus ein einheitliches endemisches Vorkommen dieses Typs im Saarland und in Lothringen anzunehmen.     

Buchbesprechungen

Ohne Zusammenfassung     

A novel regulation mechanism of DNA repair by damage-induced and RAD23-dependent stabilization of xeroderma pigmentosum group C protein

Primary DNA damage sensing in mammalian global genome nucleotide excision repair (GG-NER) is performed by the xeroderma pigmentosum group C (XPC)/HR23B protein complex. HR23B and HR23A are human homologs of the yeast ubiquitin-domain repair factor RAD23, the function of which is unknown. Knockout mice revealed that mHR23A and mHR23B have a fully redundant role in NER, and a partially redundant function in embryonic development. Inactivation of both genes causes embryonic lethality, but appeared still compatible with cellular viability. Analysis of mHR23A/B double-mutant cells showed that HR23 proteins function in NER by governing XPC stability via partial protection against proteasomal degradation. Interestingly, NER-type DNA damage further stabilizes XPC and thereby enhances repair. These findings resolve the primary function of RAD23 in repair and reveal a novel DNA-damage-dependent regulation mechanism of DNA repair in eukaryotes, which may be part of a more global damage-response circuitry.     

Noninvasive measurement of cell volume changes by negative staining

To maintain the intracellular concentration of ions and small molecules on osmotic challenges, nature has developed highly sophisticated transport systems for regulating water and ion content. An ideal measurement technique for volume changes of cells during osmotic challenges has to fulfil two requirements: it has to be osmotically inert, and it should allow online monitoring of cell volume changes. Here, a simple fluorescence microscopy-based approach is presented. Using fluorescein as a negative stain, it is possible to monitor cell volume changes without affecting the functionality of cell membranes and cell osmolarity. Measurement of Madine-Darby canine kidney (MDCK) cells after hypo- and hyperosmotic challenges reveals the main advantages of this approach: besides providing precise and reproducible quantitative data on reversible cell volume changes, the viability of the cells can be assessed directly by the appearance of stain in the cytoplasm. This becomes evident especially after hypo-osmotic challenge of glutaraldehyde-treated cells, which become leaky after fixation, followed by a massive volume change. This new approach represents a very sensitive measurement technique for cell volume changes resulting from water or ion flux, and thus seems to be an ideal tool for studying cell volume regulatory processes.     

The homogeneous photopolymerization of methyl methacrylate by colloidal cadmium sulfide

A completely new method of initiating the homogeneous radical polymerization of methyl methacrylate in bulk or in solution via the photogeneration of an electron hole pair in colloidal cadmium sulfide is presented. A polymerization mechanism involving an excited cadmium sulfide particle in both the initiation and termination steps is proposed. In the initiation a methyl methacrylate molecule is oxidized by a positive hole photogenerated in a CdS particle, which results in a novel chain-end structure of the poly(methyl methacrylate) (PMMA). Degradative chain transfer to reduced excited cadmium sulfide particles is responsible for chain termination. Thus, for the first time, a detailed polymerization mechanism in which all states of the polymerization, i.e., initiation, propagation, chain transfer and termination, is presented for the polymerization of vinyl monomers initiated by semiconductors. Thermogravimetry (TG) showed that the newly synthesized PMMA has greatly enhanced thermal stability when compared to normal radically prepared PMMA. In fact, the thermal stability approaches that of anionically prepared PMMA but is experimentally much easier to prepare. This technique enables the homogeneous embedding of CdS particles in a polymer matrix.