Reversal of diabetes by isogeneic transplantation of cultured pancreatic islets

Pancreatic islets were isolated by collagenase digestion from female Wistar rats and cultured at 20 mmol/l glucose. The enhancement of Mg++ concentration from 0.8 mmol/l up to 5.3 mmol/l had a protecting effect on the glucose-induced insulin release in the subsequent short-time incubation and prevented the age-depending decrease of B-cell function. About 1,000 cultured islets injected into portal vein normalized the plasma glucose of streptozotocin-diabetic rats. The plasma glucose patterns during the glucose load were nearly identical to healthy controls. These findings suggest that the cultured islets maintain the ability to secrete insulin in response to glucose in vitro as well as in vitro and that such islets can reverse an experimentally induced diabetes.     

Characterization of a progestin-binding macromolecule in the amphibian oocyte cytosol.

A [³H]-progestin-binding macromolecule has been isolated from $\text{R}\text{.}\text{pipiens}$ oocyte cytosol and characterized using binding assays, gel filtration, DEAE-cellulose chromatography and ultracentrifugal techniques. Macromolecules present in the prophase oocyte cytosol have a high affinity and specificity for the synthetic progestin R5020 and the intact oocyte will concentrate both R5020 and progesterone 20–40 fold from the medium. This may be the first published case of a cytosol steroid binding macromolecule in a cell system in which the steroid appears to act at an extranuclear level.     

Preparation and characterization of insulin of carp (Cyprinus carpio).

Insulin of carp (Cyprinus carpio) was isolated and crystallized. The insulin was biologically active in two tests; it decreased the blood glucose level and stimulated 14CO2-formation from glucose. The chemical properties are similar to those of insulins from other species. The insulins of carp and of mammals differ greatly immunologically. Antibodies against carp insulin crossreact with carp proinsulin.     

Kälteresistenz der Fichte

Fichtenchloroplasten durchlaufen während eines Jahres saisonbedingte charakteristische Struktur- und Funktionswechsel: Frühjahrschloroplasten, die in den alten Nadeln kurz vor und während des Knospenaustriebes gefunden werden, sind sehr groß und so sehr mit Stärke erfüllt, daß man sie als Amyloplasten bezeichnen kann. Beim Aufbau der neuen Nadelgeneration wird diese Stärke verbraucht, und es entwickeln sich aus den Amyloplasten wieder die photosynthetisch aktiven Sommerpiastiden mit einem gut entwickelten Membransystem. Während der Frosthärtung und insbesondere während der Frostperiode treten die Chloroplasten in ihrer Winterform auf: amöboide, an einer Stelle der Zelle konzentrierte, stark aufgequollene Plastiden mit einem aufgelockerten und zum Teil reduzierten Thylakoidsystem. Der Strukturwandel der Chloroplasten wird — wie die Frostresistenz selbst — durch exogene Faktoren (Tageslänge, Temperatur) ausgelöst und kann auch durch artifiziell veränderte Umgebung zu unnatürlichen Zeitpunkten ausgelöst werden. Begleitet wird der Strukturwandel von einer Veränderung der CO₂-Fixierungsrate der Fichtennadeln, die ihrerseits auf Veränderungen der photochemischen Aktivität der Chloroplasten zurückzuführen ist. In Frostexperimenten konnte gezeigt werden, daß die Frosthärtung Reaktionen auf zwei verschiedenen Ebenen auslöst: 1. Produktion von kolligativ wirksamen Membranschutzstoffen sowie 2. einer Veränderung der chemischen Zusammensetzung der Chloroplastenmembranen; zumindest letztere führt offensichtlich zu einer Verringerung der Photosyntheseleistung. Frostschädigung der Chloroplasten tritt bei nicht entsprechend stark gehärteten Nadeln auf, jedoch nicht durch direkten Einfluß der tiefen Temperatur auf das Thylakoidsystem als vielmehr durch Freisetzung membranschädigender Substanzen durch Permeabilitätsverlust plasmatischer Membranen. Wir danken Herrn Prof. Dr. O. Kandler für anregende Diskussionen und für die kritische Durchsicht des Manuskriptes. Der Deutschen Forschungsgemeinschaft wird für die finanzielle Unterstützung dieser Arbeit gedankt.     

Use of plasma norepinephrine for evaluation of sympathetic neuronal function in man

Levels of norepinephrine (NE) in human plasma have been determined by a radioenzymatic technique sufficiently sensitive to measure 0.014 ng NE per ml plasma. Several procedures which raise plasma NE levels have been compared and a standard procedure developed to evaluate sympathetic neuronal function based on the increments in plasma NE produced by postural change and a standard amount of exertion. The mean basal level of NE in plasma of 74 resting, supine, normal subjects ranging in age from 10 to 70 (mean 32.7 years) was 0.292 ± 0.016 (± SEM) ng/ml and ranged from 0.112 to 0.738 ng/ml. There was a significant correlation between age and basal levels of NE (L.R. = 0.33, p < 0.01). In 44 subjects who stood for 5 minutes after the basal sample of blood was obtained, the mean plasma level of NE increased to 0.538 ± 0.044 ng/ml and further increased to 0.778 ± 0.080 ng/ml after a subsequent isometric hand grip for 5 minutes.     

Collagenolytic Activity of Some Marine Bacteria

Reconstituted, acid-extracted collagen was used to prepare a medium to screen proteolytic marine bacteria for their ability to elaborate collagenolytic enzymes. The medium was resistant to solubilization by trypsin, hyaluronidase, chondroitinase ABC, and various marine proteinases, but was readily hydrolyzed by commercial Clostridium collagenases. Eighty-seven marine isolates collected in the vicinity of Bermuda, Oahu (Hawaii), and Stone Harbor and Cape May, N. J., were screened. Approximately 44 per cent of the isolates were capable of elaborating enzymes that hydrolyzed reconstituted collagen gels. Several cultures produced collagenolytic enzymes only when grown in the presence of collagen or degradation products of collagen, and with very few exceptions the presence of collagen in the medium greatly enhanced collagenolytic enzyme production. The enzymes from a collagenolytic Bermuda marine isolate were studied in more detail to illustrate that the enzymes capable of hydrolyzing reconstituted collagen were separable from nonspecific proteinases by zone electrophoresis and that these enzymes were true collagenases by virtue of their ability to hydrolyze native bovine Achilles'tendon obtained from three different sources.     

Myelosarcomatosis of the skin preceding leukemic generalization of acute myelomonocytic leukemia

A case report of a patient with myelosarcomatosis of the skin six months preceding leukemic generalization of acute myelomonocytic leukemia is presented. To the best of our knowledge this is the first case of a myelosarcoma with generalized skin involvement diagnosed before development of an overt myeloproliferative disease.     

Turnover of O-Glucosides of Dihydrozeatin and Dihydrozeatin-9-riboside During the Cell Growth Cycle of Photoautotrophic Cell Suspension Cultures of Chenopodium rubrum

The cellular levels of O-glucosides of ³H-(diH)Z and ³H-(diH)[9R]Z, the major short-term metabolites of ³H-(diH)Z having been exogenously supplied to photoautotrophically growing suspension cell cultures of Chenopodium rubrum, decreased significantly during further culture, irrespective of whether the cells were maintained in the stationary phase or were transferred to conditions restoring cell divison. Metabolism of both compounds was more pronounced during the active growth phase than during the stationary phase. The O-glucosides were converted preferentially to polar compounds of as yet unknown nature, which were partly excreted into the medium. The cellular pools of both glycosides remained compartmented within the vacuole. In contrast to the O-glycosides, the small cellular pools of the aglycones ³H-(diH)Z and ³H-(diH)[9R]Z maintained their level during the experimental period of 30 days. Small amounts of the glucosides, as well as of the aglycones, were recovered from the medium and could have resulted from the lysis of a few cells. The results demonstrate, for the first time, that O-glucosides of cytokinins are not irreversibly deposited within the vacuole of plant cells but may serve to maintain a small, but more or less constant pool of extra-vacuolar, presumably cytosolic, aglycones. (DiH)Z and its derivatives could be demonstrated to be endogenous cytokinins of Chenopodium rubrum suspension cultured cells occurring along with those of the isopentenyladenine and zeatin types.