Novel streptopyrroles from Streptomyces rimosus with bacterial protein histidine kinase inhibitory and antimicrobial activities.

A series of halogenated pyrrolo [2,1-b] [1,3] benzoxazines (1 approximately 9) was isolated from fermentations of an actinomycete strain X10/78/978 (NCIMB40808), identified as Streptomyces rimosus, during a microbial extract screening programme to identify inhibitors of bacterial histidine kinase. The structures of these compounds were elucidated by spectroscopic methods including the HMQC, HMBC and INADEQUATE NMR experiments. The structure of 1 was confirmed by X-ray crystallographic studies. Compounds 5 and 6 were produced in fermentations in the presence of NaBr and NaI respectively. The most abundant member of the series, streptopyrrole, 1, inhibited the nitrogen regulator II (NRII) histidine kinase from Escherichia coli with an IC50 of 20 microM and exhibited antimicrobial activity against a range of bacteria and fungi.

Cochliobolic acid, a novel metabolite produced by Cochliobolus lunatus, inhibits binding of TGF-alpha to the EGF receptor in a SPA assay.

Cochliobolic acid (1), a novel biologically active natural product, is produced by submerged fermentation of Cochliobolus lunatus. Compound 1 was determined to be a novel polyketide possessing a substituted tetrahydrofuran ring, a conjugated polyene chain and a 1,2-diketone moiety, by interpretation of NMR, MS, and UV/vis spectroscopic data. Compound 1 inhibits the binding of TGF-alpha to the EGF receptor of the human epidermal cell line A431 in a SPA assay with an IC50 of 1.6 microM.

Xenovulene A, a novel GABA-benzodiazepine receptor binding compound produced by Acremonium strictum.

Xenovulene A, a novel inhibitor of benzodiazepine binding to the GABA-benzodiazepine receptor is produced by submerged fermentation of Acremonium strictum. It was isolated from the mycelium by solvent extraction and purified by chromatography on Sephadex LH-20 and octadecyl silica. The structure of xenovulene A was determined to be a novel oxygenated sesquiterpene containing a humulene moiety by interpretation of various spectroscopic data, especially from 2D NMR experiments. Xenovulene A inhibited binding of the benzodiazepine, flunitrazepam, with an IC50 of 40 nM in an in vitro assay using bovine synaptosome membrane preparations.

High-performance liquid chromatography comparison of supercritical-fluid extraction and solvent extraction of microbial fermentation products.

The use of supercritical fluids for the extraction of biologically active compounds from the biomass of microbial fermentations has been compared with extraction using the organic solvents methanol and dichloromethane. Compounds representing a range of structural types were selected for investigation. All the extracts obtained were examined using reversed-phase high-performance liquid chromatography. The extractability of metabolites using unmodified and methanol-modified supercritical-fluid carbon dioxide was examined in particular detail for six microbial metabolites: chaetoglobosin A, mycolutein, luteoreticulin, 7,8-dihydro-7,8-epoxy-1-hydroxy-3-hydroxymethyl-xanthone-8-carboxyl ic acid methyl ester, sydowinin B and elaiophylin. The extraction strength of supercritical-fluid carbon dioxide alone appeared to be lower than that of dichloromethane. All the components of interest that were extractable with dichloromethane and methanol were also extractable with methanol-modified carbon dioxide.

Beta-adrenergic receptors in human anterior optic nerve: an autoradiographic study.

Sections of human anterior optic nerve and nerve head were incubated in a physiological solution containing a radiolabelled beta blocker at a low concentration. The beta blocker used was (-)-(125iodo)-cyanopindolol, which has a high affinity and specificity for beta-adrenergic receptors. Concurrent incubations were performed with a great excess of unlabelled beta blocker added to demonstrate non-specific binding. Following incubation the sections were washed and dried. They were then apposed to photographic film for 5 days and developed. Incubations were performed with the stereoisomers of propranolol and an alpha blocker as well as specific beta-one and beta-two blockers. Beta-adrenergic receptors were demonstrated in anterior optic nerve and optic nerve head. The majority were of the beta-two subtype.

[Ectopic or migrating spleen and supernumerary spleens: detection and identification with 99mTc, 51Cr and 113In radioisotopes]. / Bazo ectópico o migratorio y bazos supernumerarios. Detección e identificación con radioisótopes: Tc 99, Cr 51 In 113.

Congenital malformations of the spleen are rare. We report a patient with an ectopic spleen located in the left iliac fossa, which was excised in order to prevent severe complications such as torsion of the pedicle, rupture or infection. A second patient with idiopathic thrombocytopenic purpura presented with an accessory spleen located retroperitoneally. Removal of this spleen following removal of the normotopic one resulted in cure of purpura. The clinical, radiological and radioisotopic studies used to locate and identify these malformations are described.

Gammasubdurography in the diagnosis of chronic subdural bilateral and communicating effusion in infants.

The results obtained by means of Gammasubdurography (G.S.G.) in 37 infants having chronic subdural bilateral effusions, are presented. The use of this procedure, which consists of unilateral injection of Radioiodinated Human Sero Albumin (RIHSA-I 131), into the subdural effusion, is suggested for the determination of a communication between the two cavities. At the same time it is possible to get valuable information about their exact localization and extension. Once the communication is diagnosed, the treatment proposed is internal or external unilateral drainage. The method is safe and is performed in a short time which permits its use in the screening of these patients, especially in conjunction with Gammaencephalography (G.E.G.) and Computer Tomography (CT), patients to it. The test (G.S.G.) has been used by us since 1979. All our cases are included in this series. All of them had been diagnosed by subdural puncture, transillumination, G.E.G. and or CT Scan, as having bilateral subdural collections. All the patients received a saturated iodine solution, 24 hours in advance and for 10 days, as a thyroid blocking agent, which was administered in the usual oral dosage. The radiopharmaceutical administration was performed through a unilateral subdural puncture in a dose of 50 to 80 microcurie of RIHSA-I 131 with a high specific activity. Immediately after this, sequential analog images were obtained with the patient supine and in anterior and lateral head projections. This was accomplished by using a PICKER DYNA 4 Gammacamera equipped with a medium energy parallel hole collimator. The interval between the images was determined during the test in agreement with the findings.

Aporte de la angiografia isotopica al diagnostico de muerte cerebral. / Contribution of isotopic angiography to the diagnosis of cerebral death

Se estudian mediante angiografia isotopica 10 pacientes del Instituto de Neurocirugia de Santiago de Chile con el diagnostico presuntivo de muerte cerebral por diversas etiologias. La positividad del metodo fue de 100%. Se recomienda su empleo como un parametro mas para el diagnostico definitvo de muerte cerebral.Se sugiere la conveniencia de legislar claramente al respecto

Gamaencefalografia con Tc - 99m DTPA en el diagnostico de la ventriculitis / Gammaencephalography with Tc - 99m DTPA in the diagnosis of ventriculitis

Se destaca la importancia del diagnostico precoz de la ventriculitis. Es igualmente imperativo contar con medios que permitan seguir la evolucion bajo tratamiento, asi como certificar la curacion, total o parcial, de este cuadro. Se presenta una serie preliminar de gamaencefalografia con Tc - DTPA que se ha mostrado muy alentadora en estos aspectos. Se destaca la inocuidad, rapidez y economia del metodo

Effects of chartreusin on cell survival and cell cycle progression.

Chartreusin was lethal to both L1210 and P388 cells in culture with 90% of the cells being killed after a 24-hr exposure to 1.1 and 2.6 microgram/ml, respectively. The lethality of the drug increased in direct proportion to dose and exposure time. Both L1210 and Chinese hamster ovary cells in S phase were more sensitive to the lethality of the drug than were their corresponding non-S-phase cells. L1210 cells were partially synchronized by exposing an asynchronous culture to [methyl-3H]thymidine (20 Ci/mmol) and Colcemid for 3 hr. Synchronous culture of Chinese hamster ovary cells was established by planting mitotic cells. The progression of cells through the cell cycle was studied with flow microfluorometry both in the presence of the drug and after the drug had been washed off. In the presence of chartreusin the progression of mitotic cells into G1 was not affected. The movement of G1 cells into S was slower, and the movement of G2 cells into mitosis was blocked. When the drug was removed, the G2 to M block persisted for at least 4 hr but the progression of G1 cells to S was no longer inhibited.

Antitumor activity and preliminary drug disposition studies on chartreusin (NSC 5159).

Chartreusin has exhibited significant therapeutic activity against three experimental mouse tumors (ascitic P388, L1210 leukemia, and B16 melanoma) when tumor cells were inoculated i.p. and drug was administered i.p. In further testing against P388 leukemia, no activity was observed when drug was administered p.o., s.c., or i.v. Chartreusin was very slowly absorbed from the small intestine, thus explaining the lack of activity when administered p.o. When given i.p., the drug precipitated in the peritoneal cavity and was slowly absorbed over several hr. The strong activity observed by this route was related to the prolonged and intimate contact of drug with tumor cells in the peritoneal cavity. Upon s.c. administration, extensive precipitation occurred. Subsequent dissolution and absorption from the injection site were very slow, and measured plasma and tissue levels were quite low. Biliary excretion of chartreusin, the predominant route of elimination. was very rapid, with 80 to 100% of the dose appearing as unchanged drug in the bile within 6 hr after i.v. administration. Rapid biliary excretion after i.v. administration was reflected in a rapid decline in plasma and tissue concentrations to levels (shown by in vitro cell kill experiments) less than those necessary to kill P388 cells. When the bile ducts of i.v.-dosed leukemic mice were ligated, therapeutic activity was observed, confirming that the physiological disposition of chartreusin exerts a major influence on its therapeutic utility.