Cellulolytic fungi isolated by the screened substrate method

Zusammenfassung Eine neue Methode zur spezifischen Isolierung von zellulolytischen Bodenpilzen wird beschrieben: Als Substrat dient Whatman-Chromatographiepapier 3 mm, rückseitig überschichtet mit Polythene. Ein Glasfasergewebe über dem Papierstreifen schützt vor dem direkten Kontakt des Substrats mit der Erde. Zellulolytische Pilze durchwachsen das Glasfasergewebe, bauen die Zellulose ab, wodurch eine direkte Mikroskopie der freigelegten Polytheneschicht ermöglicht wird.     

An improved bioassay method for kinins

Zusammenfassung Unter Ausnützung der besonderen Empfindlichkeit der Femoralarterie des Kaninchens für Kinin wurde die autoperfusionierte Hinterextremität beobachtet. Intraarterielle Injektion von 0,5 ng synthetisiertem Bradykinin ergab eine messbare, dosisabhängige Vasodilatation in fast allen Versuchstieren. Dieses Kreislaufpräparat erweist sich zur Kinin-Bestimmung als besonders geeignet.     

Platelets and viruses: an ambivalent relationship

Thrombocytopenia is a frequent complication of viral infections providing evidence that interaction of platelets with viruses is an important pathophysiological phenomenon. Multiple mechanisms are involved depending on the nature of the viruses involved. These include immunological platelet destruction, inappropriate platelet activation and consumption, and impaired megakaryopoiesis. Viruses bind platelets through specific receptors and identified ligands, which lead to mutual alterations of both the platelet host and the viral aggressor. We have shown that HIV-1 viruses are internalized specifically in platelets and megakaryocytes, where they can be either sheltered, unaltered (with potential transfer of the viruses into target organs), or come in contact with platelet secretory products leading to virus destruction and facilitated platelet clearance. In this issue, we have reviewed the various pathways that platelets use in order to interact with viruses, HIV and others. This review also shows that more work is still needed to precisely identify platelet roles in viral infections, and to answer the challenge of viral safety in platelet transfusion.     

Leonurine,an improved synthesis

Summary Leonurine (1) is the uterotonic principle ofLeonurus artemisia. We have developed a simple, high-yield synthetic procedure of1 that is adaptable to large scale preparation. The synthesis involves the condensation of syringic acid and 4-guanidino-1-butanol hydrochloride in the presence of DDC using 11 HMPT-ether as solvent. The synthetic leonurine showed uterotonic activity in vivo and in vitro.Acknowledgment. This work was partly supported by World Health Organization, Geneva, Switzerland.     

Leonurine, an improved synthesis.

Leonurine (1) is the uterotonic principle of Leonurus artemisia. We have developed a simple, high-yield synthetic procedure of 1 that is adaptable to large scale preparation. The synthesis involves the condensation of syringic acid and 4-guanidino-1-butanol hydrochloride in the presence of DDC using 1:1 HMPT-ether as solvent. The synthetic leonurine showed uterotonic activity in vivo and in vitro.     

Rapid recording of the fluorescence spectrum emitted by an isolated living cell]

In order to use the selectivity of fluorescence emission for biomedical purposes, a microspectrofluorimeter has been built around an inverted microscope. The excitation is supplied by a 450 W Xenon lamp coupled with a monochromator allowing excitation from 230 to 600 nm. The fluorescence is analysed by a Grism (association prism-grating) and the spectrum focused on the 500 channels of the target of an Optical Multichannel Analyser. Related to good resolution and dispersion (0.44 nm/channel), improvement of signal to noise ratio (dark current suppression, and accumulation of spectra), this microspectrofluorimeter with high sensitivity is well adapted to the study of biological mechanism in single living cells (macrophages, monocytes, lumphocytes).     

An improved electrophoretic method for a screening program for haemoglobinopathies

Summary A method for a screening program for haemoglobinopathies in a starch agar gel mixed with saponin is presented. Normal and abnormal blood containing haemoglobins S, C, I, M Boston, D Punjab, beta thalassaemia major and beta thalassaemia minor, were applied, in a tray with the capacity for 100 samples. The electrophoresis was performed in 45 min using 300 V. This method offers special advantages for the examination of a large number of samples, using a small amount of whole blood and without the previous preparation of haemoglobin solution.Acknowledgments. We would like to express our gratitude to Dr C. Daghlian and Dr Lewis J. Greene for their valuable suggestions. We also thank the Conselho Nacional do Desenvolvimento Científico e Tecnológico, CNPq, for financial support.     

An improved technique of preparing primary cultures of isolated cells from adult frog kidney

Zusammenfassung Eine verbesserte Technik zur Gewinnung der ersten Einzelschichtbildungen von Froschnierenzellen wurde entwickelt. Die Zellen werden in neuem auflösendem Nährboden isoliert und wachsen auf modifiziertem Eagle-Nährboden mit 13% Kalbsserum. Nach 10 Tagen zeigt sich stark aktives mitotisches Zellwachstum in der Kultur.     

Contractility cycle of an isolated gastropod ventricle

Zusammenfassung Plötzliche Dehnungen oder Entspannungen während des Eigenrhythmus der Herzkammer vonBusycon canaliculatum wurden dazu benützt, um den Verlauf des Aktivitätszustandes zu untersuchen. Sowohl Anstieg, wie auch Abfall des «active state» waren entsprechend langsam wie bei Wirbeltier-Herzmuskeln. Das tetanisierbare Schneckenherz stellt somit ein gutes Versuchsobjekt für die Aktivierung des Herzmuskels dar, da die maximale Kraft unabhängig von der Zeit ist.

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Research supported by National Science Foundation grant No. GB-1001.     

An immunofluorescent method for identification of isolated thyrotropic cells

Summary A sensitive and specific immunofluorescent method for identification of thyrotropic cells was developed. The TSH-producing cells were found to be heterogenic in their morphology and intensity of staining.     

Prevention or acceleration of type 1 diabetes by viruses

Type 1 diabetes is an autoimmune disease characterized by the destruction of insulin-producing pancreatic β-cells. Even though extensive scientific research has yielded important insights into the immune mechanisms involved in pancreatic β-cell destruction, little is known about the events that trigger the autoimmune process. Recent epidemiological and experimental data suggest that environmental factors are involved in this process. In this review, we discuss the role of viruses as an environmental factor on the development of type 1 diabetes, and the immune mechanisms by which they can trigger or protect against this pathology.     

A method for the electrical stimulation and registration of the contractions of an isolated skeletal muscle ofPeriplaneta americana L.

Zusammenfassung Eine einfache Methode der elektrischen Reizung eines isolierten Extensormuskels (vom Bein der KüchenschabePeriplaneta americana L.) wurde beschrieben. Die Methode eignet sich zum Studium des Einflusses von Giften.     

Measurement of fluorescence decay of substances absorbed by an isolated living cell: an experimental device and early results]

A microfluorometric system allowing the mesurements of fluorescence decay (i.e. fluorescence lifetime) has been built. It will complete the microspectrofluorometric studies of absorbed compounds-polycyclic aromatic hydrocarbons, metabolites of benzo (a) pyrene-by single living cells and allows a better understanding of the intake and metabolisation of these compounds. The preliminary results with benzo (a) pyrene, dibenzocarbazole, pyrene are shown.     

An immunofluorescent method for identification of isolated thyrotropic cells.

A sensitive and specific immunofluorescent method for identification of thyrotropic cells was developed. The TSH-producing cells were found to be heterogenic in their morphology and intensity of staining.     

An improved method for flow dialysis studies with highly increased diffusion rates

Summary An improved flow dialysis procedure with highly increased diffusion rates has been developed allowing the study of small changes in the rate of diffusion. The application of the method described with only a few individual experiments, and with the use of small amounts of biological material, gives much information about binding systems.This work was supported by the Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung (grant No. 3.1650.73).     

An improved method of transplantation on chicken chorioallantoic membrane (CAM)

Summary An improved method for grafting on the chicken CAM is described and compared with other CAM grafting methods.The author is very grateful to Prof. L. Vakaet, RUCA Antwerpen, to Dr and Mrs M. Mareel, RUG Gent, for their valuable suggestions and to Mrs S. De Wolf-Van Rompaey for her excellent technical assistance. The author is also indebted to Mr F. De Bruyn for making the drawing.