Uptake of D-glucose anomers by rat retina

Summary Uptake ofd-glucose anomers by isolated rat retina was studied. After 3 min incubation at 37°C in the presence of or anomer (750 g/ml), a significantly greater uptake (1.32 mg/g wet tissue) of -anomer was observed compared with that of -d-glucose (1.11 mg/g wet tissue). This result and other data suggest that the carrier ford-glucose transport in the retina prefers the -anomer stereospecifically.Acknowledgment. The authors are grateful to Mr S. Suzuki for his technical assistance.     

The molecular structure of the benzilic acid rearrangement product of 3α, 17β-diacetoxy-11-hydroxy-12-oxo-5β-androst-9(11)-ene

Zusammenfassung Die Struktur desp-Brombenzoates des Benzilsäureumlagerungsproduktes von 3, 17-Diacetoxy-11-hydroxy-12-oxo-5-9(11)-androsten wurde durch dreidimensionale Röntgenstrukturanalyse eines Einkristalls als 3-p-Brombenzoat des 11-Carboxy-3, 11, 17-trihydroxy-13-C-nor-5-androstan 11a, 17-Laktons erkannt.     

17β-Hydroxymethyl-Steroide: Darstellung von Derivaten des 17β-Hydroxymethyl-4-androsten-3-ons

Summary Starting from methyl 3-oxo-4-etienate, the authors prepared 17-hydroxymethyl-4-androsten-3-one and 11-hydroxy-17-hydroxymethyl-4-androsten-3-one. Chlorination of 17-acetoxymethyl-4-androsten-3-one yielded 4-chloro-17-acetoxymethyl-4-androsten-3-one. 17-Hydroxymethyl-1, 4-androstadien-3-one was obtained from 17-hydroxymethyl-4-androsten-3-one, both by chemical and biological methods.     

Purification of platelet-derived endothelial cell growth inhibitor and its characterization as transforming growth factor-β type 1

In 1986, Brown and Clemmons (Proc. natl Acad. Sci. USA83 (1986) 3321) showed that platelets contain a substance, platelet-derived growth inhibitor (PDGI), that inhibits in vitro endothelial cell replication. Although platelets are rich in transforming grwoth factor (TGF-), PDGI was considered not to be related to TGF-, on the basis of its reported properties (extraction from platelets at neutral pH, binding to heparin-Sepharose). However, we purified PDGI to near homogeneity and showed that on the basis of HPLC retention behavior, in vitro growth inhibitory activities with several cell types, receptor binding, and immunoneutralization of growth inhibitory activity with specific anti-TGF- type 1 antibodies, PDGI is most probably identical with TGF- type 1.     

Thrombospondin co-localises with TGFβ and IGF-I in the extracellular matrix of human osteoblast-like cells and is modulated by 17β estradiol

Thrombospondin (TSP) is a multifunctional glycoprotein which is synthesised by several cell types including osteoblasts, and incorporated into the extracellular matrix (ECM) of these cells. The function and regulation of TSP in bone is not clear. In this study, using a long term culture model of human osteoblast-like cells, we examined the distribution of TSP in the ECM and its modulation by added estradiol. In this model the osteoblast-like cells form a regular multilayer which continues to increase in depth up to 50 days post confluence. In the ECM of these cultures and in 19-week fetal bone, the bone markers osteocalcin and alkaline phosphatase were diffusely distributed in the matrix. In contrast, labelling for TSP was concentrated, confined to the banded collagen and its immediately adjacent ECM. This pattern of labelling resembled that of the growth factors transforming growth factor-I (TGF), and insulin-like growth factor-I (IGF-I), with which TSP label co-localised. Labelling intensities were comparable between fetal bone and the in vitro material for TSP, TGF and IGF-I. TSP label was present by 10 days post confluence, reached a maximum by 20 days, and declined slowly thereafter, a time course which was similar to that of IGF-I. Incubation of osteoblast-like cell cultures with 17 estradiol resulted in an increase in multilayer depth and a maximal 3-fold increase in TSP labeling at 30 days as well as approximately 2-fold increases for TGF and IGF-I. The dose-response relationship for these responses to estradiol treatment was biphasic with maximal increases at 10^–10 M–10^–11 M of added estradiol. Treatment with 17 estradiol produced labelling intensities that were not significantly different from controls. Studies with other cell types have suggested that TSP may be involved in modulation of growth factor activity. The similarities between TSP, TGF and IGF-I, in terms of their distribution and regulation by 17 estradiol treatment, may indicate a role for TSP in modulating bone cell proliferation and function through interaction with local growth factors.     

Butyrate-induced reactivation of the fetal globin genes: A molecular treatment for theβ-hemoglobinophaties

The inherited -hemoglobinopathies (sickle cell disease and thalassemia) are the result of a mutation in the adult () globin gene. The fetal globin chain, encoded by the globin genes, can substitute for the mutated or defective globin chain, but expression of the globin gene is developmentally inactivated prior to birth. Reinducing expression of the normal fetal globin genes is a preferred method of ameliorating sickle cell disease and the thalassemias. Stimulation of as little as 4–8% fetal globin synthesis in the bone marrow can produce >20% fetal hemoglobin in the peripheral circulation, due to enhanced survival of red blood cells containing both sickle and fetal hemoglobin, compared to those containing sickle hemoglobin alone. Butyric acid and butyrate derivatives are generally safe compounds which induce fetal hemoglobin production by stimulating the promoter of the fetal globin genes. An initial trial with the parent compound, delivered as Arginine Butyrate, has demonstrated rapid stimulation of fetal globin expression to levels that have been shown to ameliorate these conditions. Phase 1 trials of an oral butyrate derivative with a long plasma half-life have just begun. These agents now provide a specific new apporach for ameliorating these classic molecular disorders and merit further investigation in larger patient populations.     

Proteolytic generation and aggregation of peptides from transmembrane regions: lung surfactant protein C and amyloid β-peptide

The formation of amyloid fibrils is associated with several devastating diseases in humans and animals, including e.g. Alzheimers disease (AD) and the spongiform encephalopathies. Here, we review and discuss the current knowledge on two amyloid peptides: lung surfactant protein C (SP-C) and the amyloid -peptide (A), implicated in human lung disease and in AD, respectively. Both these hydrophobic peptides are derived from the transmembrane region of their precursor protein, and can transit from a monomeric -helical state to a -sheet fibril. The helices of SP-C and A are composed of amino acid residues with inherently higher propensities for strand than helix conformation. Their helical states are stabilized by a membrane environment, and loss of membrane association thus promotes structural conversion and fibril formation. We speculate that the loss of structural context for sequences with a high propensity for formation of sheets may be a common feature of amyloid formation in general.Received 9 July 2003; received after revision 15 August 2003; accepted 3 September 2003     

Hemmung der Phosphodiesterase aus Rattenherzen durch Intensain

Summary Intensain causes in vitro a significant and apparently competitive inhibition of phosphodiesterase, which transforms the 3,5-AMP to 5-AMP. These results explain some intensain effects, especially the period of latency to reach the maximum effect, the inotropic action and its reaction under the influence of-blocking and-stimulating agents^10–13.

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3-(-Diäthylamino-äthyl)-4-methyl-7-carbäthoxy-methoxy-2-oxo-(1,2-chromen), Carbochromen.     

Zur Konstitution des Resibufogenins und Artebufogenins

Summary The structure of Resibufogenin is unambiguously shown to be 3-hydroxy-14, 15-oxido-bufadien-(20, 22)-olide on the basis of new degradation work. Artebufogenin A and Artebufogenin B are 3-hydroxy-14-15-keto-bufadien-(20, 22)-olide and 3-Hydroxy-14-14-keto-bufadien-(20, 22)-olide, respectively.     

The in vivo expression of the globin genes of theβ cistron in γ-,δ-, andδβ-thalassemia heterozygotes

There is considerable evidence suggesting that the switch from to and chain production after birth is due, in part, to silencing of the genes by stage-specific factors which bind to their promoters and to the competition from the adult ( and ) genes for a common enhancer element located in the locus control region. As a consequence one can expect that the increased Hb F production in adults with hereditary persistence of fetal hemoglobin or -thalassemia is directed mainly by -globin genes in cis to the deletion(s) responsible for these conditions. Here we review data on heterozygotes with -, -, or -thalassemia, who also had an^AT mutation, in cis or in trans, which was used as a marker of gene expression. The results show that a deletion affecting adult genes favors the expression of genes in cis, while the deletion of a single gene does not affect the expression of the gene in cis but leads to a faster switch postnatally.     

Synthese von 5α- und 5β-Androstan-17β-ol-3-on-17-acetat aus Hyodesoxycholsäure

Summary 5- and 5-androstane-17-ol-3-one-17-acetate have been prepared from 5-androstane-6, 17-diol-3-one-17-acetate by a synthesis involving directedHuang-Minlon-reduction.Separation of 5-androstane-17-ol-3-one from its 5-isomer could readily be achieved by crystallisation of their 3-ethylenketals from acetone.     

Neue Synthesen des Chloramphenicols und deren stereochemischen Beziehungen

Summary Two new syntheses of Chloramphenicol are described starting from the diastereoisomers of -phenylserinmethyl ether and cinnamyl alcohol methyl ether respectively. The configurational correlation of the diastereoisomers of -phenylserin-methyl ether with -phenylserin and chloramphenicol is discussed. A new method for transforming erythro--phenylserinol into threo--phenylserinol is described. New examples of the Neighboring group effect were studied. The sterical course of the addition of methylhypobromite to the double bond is discussed.     

Defensive steroids from a carrion beetle (Silpha americana)

Summary The defensive anal effluent discharged bySilpha americana in response to disturbance contains a mixture of steroids stemming from a glandular annex of the rectum. The compounds have been characterized as 15-hydroxyprogesterone (1, principal component), 5-pregnan-15-ol-3, 20-dione (2), 5-pregnan-3, 15-diol-20-one (3), 5-pregnan-7, 15-diol-3,20-dione (4), 5-pregnan-3, 7, 15-triol-20-one (5), 5-pregnan-16-ol-3,20-dione (6), and 5-pregnan-3, 16-diol-20-one (7), none previously found in insects. Bioassays with jumping spiders showed compounds1 and6 to be feeding deterrents at the 1 g level.Paper No. 78 of the series: Defense Mechanisms of Arthropods. Study supported by NIH (Grants AI-02908, AI-12020). We thank Maura Malarcher and Maria Eisner for excellent technical help, and the Squibb Institute of Medical Research for samples of authentic reference compounds.     

Evidence for the extranuclear localization of thymosins in thymus

A new radioimmunoassay has been developed for thymosin ₄ by generating rabbit polyclonal antibodies against the synthetic N-terminal peptide fragment 1–15 coupled to KLH. The synthetic analogue [Tyr¹²]-thymosin ₄ (1–15) was used as tracer. This radioimmunoassay, with a useful range of 10–1000 pmoles, showed cross-reactivity with the second homologous -thymosin of man and rat (thymosin ₁₀) but not of calf (thymosin ₉). This radioimmunoassay, together with an improved radioimmunoassay for the N-terminus of parathymosin , was employed for the measurement of the levels of thymosin ₄ and parathymosin in nuclear and extranuclear extracts of calf thymus. The bulk of these polypeptides was found in the extranuclear material whereas only traces were observed in the nuclear environment, which indicates the extranuclear localisation of - and -thymosins.     

26-Hydroxy-β-ecdysone,a metabolite of β-ecdysone in the blowfly,Calliphora erythrocephala

Summary 26-Hydroxy--ecdysone has been identified as a metabolite of the moulting hormone, -ecdysone inCalliphora erythrocephala.     

Hydrolysis of amino acid β-naphthylamides by aminopeptidases in the parotid gland

Zusammenfassung Die Aktivität der Aminopeptidasen in Ohrspeicheldrüsen wurde gemessen. Glycyl-Prolin-naphthylamid, Alanin-naphthylamid, Leucin-naphthylamid, Methionin-naphthylamid, und Arginin-naphthylamid wurden von der Mikrosomenfraktion und der löslichen Fraktion schnell gespalten. Das Glycyl-Prolin-naphthylamid spaltende Enzym war in Ohrspeicheldrüsen in relativ grösserer Menge vorhanden. Die Aufspaltung von Glycyl-Prolin-naphthylamid in Glycyl-Prolin und-Naphthylamin wurde papierchromatographisch nachgewiesen.     

Biosynthesis ofα- andβ-ecdysone by the CrayfishOrconectes limosus in vivo and by its Y-Organs in vitro

Summary - and -ecdysone were synthesized from labelled cholesterol by premolt crayfish in vivo and by their Y-organs in vitro.     

Wirkung von 6β-Methoxy-9β,10α-pregna-4,6-dien-3,20-dion

Summary 6-Methoxy-9,10 -pregna-4,6-diene-3,20-dione inhibites the ⁴-3-oxosteroid-5-reduction in microsomes and the ⁴-3-oxosteroid-5-reduction in the soluble fraction of male rat liver. The 3- and 3-hydroxysteroid dehydrogenase are not inhibited by this substance.

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Diese Arbeit wurde von der Firma Hoffmann-La Roche, Basel, unterstützt.     

Human and rodent type 1 11β-hydroxysteroid dehydrogenases are 7β-hydroxycholesterol dehydrogenases involved in oxysterol metabolism

Interconversion between cortisone and the glucocorticoid receptor ligand cortisol is carried out by 11-hydroxysteroid dehydrogenase (11-HSD)isozymes and constitutes a medically important example of pre-receptor control of steroid hormones. The enzyme 11-HSD type 1 (11-HSD1) catalyzes the conversion of cortisone to its active receptor-binding derivative cortisol, whereas 11-HSD type 2 performs the reverse reaction. Specific inhibitors against the type 1 enzyme lower intracellular levels of glucocorticoid hormone, with an important clinical application in insulin resistance and other metabolic disorders. We report here on the in vitro oxysterol-metabolizing properties of human and rodent 11-HSD1. The enzyme, either as full-length, membrane-attached, or as a transmembrane domain-deleted, soluble form, mediates exclusively conversion between 7-ketocholesterol and 7-hydroxycholesterol with similar k_cat values as observed with glucocorticoid hormones. Thus, human, rat, and mouse 11-HSD1 have dual enzyme activities like the recently described 7-hydroxysteroid dehydrogenase/11-hydroxysteroid dehydrogenase from hamster liver, but differ fundamentally from the latter in that 7-OH rather than 7-OH dehydrogenase constitutes the second activity. These results demonstrate an enzymatic origin of species differences in 7-oxysterol metabolism, establish the origin of endogenous 7-OH cholesterol in humans, and point to a possible involvement of 11-HSD1 in atherosclerosis.Received 30 December 2003; received after revision 16 February 2004; accepted 16 February 2004