1,2-Dihydro-1-hydroxy-2-(organosulfonyl)areno[d] [1,2,3]diazaborines 2 (arene = benzene, naphthalene, thiophene, furan, pyrrole) were synthesized by reaction of (organosulfonyl)hydrazones of arene aldehydes or ketones with tribromoborane in the presence of ferric chloride. The activities of 2 against bacteria in vitro and in vivo (Escherichia coli) were determined and structure-activity relationships are discussed. Included in this study are 2,3-dihydro-1-hydroxy-2-(p-tolylsulfonyl)-1H-2,1-benzazaborole+ ++ (3) and 1-hydroxy-1,2,3,4-tetrahydro-2-(p-tolylsulfonyl)-2,1-benzazabor ine (4) as well as the carbacyclic benzodiazaborine analogue 4-hydroxy-3-(p-tolylsulfonyl)isoquinoline (7). The nature of the active species is briefly discussed.

The possibility of improving the antibacterial activities of drugs normally excluded by Gram-negative bacteria with polymyxin B nonapeptide (PMBN) has been explored. In vitro, PMBN rendered clindamycin, erythromycin, novobiocin, rifampicin and vancomycin very active against a number of Gram-negative enteric bacteria. The drug also sensitized the previously resistant bacterial strains to human, mouse or guinea pig serum. However, parenterally administered PMBN failed to influence bacterial growth in chambers implanted into mice and guinea pigs. It was also ineffective in experimental septicaemia at a dose of up to 200 mg/kg or when combined with antibiotics with which it interacted synergistically in vitro.

The possibility of predicting the clinical effects of cytokines from in vitro data is discussed, using GM-CSF as an example. GM-CSF incubated with bone marrow cells has been shown to induce proliferation and colony formation, predominantly of the colony-forming unit granulocyte and granulocyte-macrophage types. Daily treatment of normal monkeys with GM-CSF resulted in transient neutropenia followed by neutrophilia. After withdrawal of GM-CSF the neutrophil levels returned to baseline. Predictably, GM-CSF administration results in accelerated neutrophil recovery in patients with chemotherapy-induced neutropenia. GM-CSF has also been shown to induce microbial killing by neutrophils and monocytes in vitro. This activity translated into a dose-related protection of GM-CSF-pretreated mice infected with lethal doses of micro-organisms. Interleukin-3 (IL-3) increases the cellularity of the bone marrow and GM-CSF can induce mobilization of bone marrow cells into the peripheral blood. Therefore, it was predicted and subsequently proved that a combination of these cytokines is synergistic, increasing the yields of peripheral blood progenitor cells which could be collected and then retransplanted into patients undergoing myeloablative chemotherapy. Monkeys injected with recombinant human IL-3 and GM-CSF had increased antibody titres to human IL-3 compared with monkeys given IL-3 alone, suggesting a potential use of GM-CSF which was not predicted from its in vitro results, that of vaccine adjuvancy.(ABSTRACT TRUNCATED AT 250 WORDS)

SDZ MRL 953, a new synthetic monosaccharidic lipid A, was investigated in vitro and in vivo for immunopharmacological activities. In experimental models of microbial infections, the compound was highly protective when it was administered prophylactically either once or three times to myelosuppressed or immunocompetent mice. The 50% effective doses of SDZ MRL 953 varied with the infectious agents and the route of its administration. In all cases, the 50% effective doses were about 103 times higher than those obtained with endotoxin from Salmonella abortus equi. SDZ MRL 953 was, however, less toxic than lipopolysaccharide by a factor of 104 to >7 x 105 times in galactosamine-sensitized mice. The compound was also an effective inducer of tolerance to endotoxin. Hence, repeated dosing with the compound induced a transient resistance (.1 week) to lethal challenges with endotoxin. In vitro, the compound was devoid of intrinsic antimicrobial activity, but it moderately induced the release of cytokines from monocytes and primed human neutrophils for the enhanced production of reactive oxygen metabolites in response to a soluble stimulus. The results presented here suggest that SDZ MRL 953 may be useful in a clinical setting for enhancing resistance to infections, particularly in patients undergoing myelosuppressive chemotherapy or irradiation, and for the prophylaxis of endotoxin shock.Lipopolysaccharides (LPS) are common constituents of cell walls of gram-negative bacteria. They can cause a whole array of pathophysiological effects and are also the most powerful immunostimulants known. It is generally accepted that the lipid A moiety, the terminal acylated P(1-6)glucosamine disaccharide-1,4'-diphosphates of endotoxin, is responsible for immunopharmacological activity and induction of endotoxicity, such as changes in leukocyte count, disseminated intravascular coagulation, and multiorgan failure leading to irreversible shock and death (5,21,25).Extensive studies have unsuccessfully addressed the possibility of harnessing the immunopharmacological activities of endotoxins by using various detoxifying approaches (17,20). The elucidation of the correct structure of lipid A (8, 26) and the subsequent success in the total synthesis of biologically active lipid A and analogs (9-12, 27) have rekindled interest in the possibility of separating the immunostimulatory and toxic moieties of endotoxin. Efforts to identify beneficial immunostimulatory lipid A derivatives have concentrated on synthetic analogs representing both the nonreducing (10-12) and reducing sugar moieties, such as lipids X and Y (15,27). Synthetic lipid A subunits of the nonreducing sugar moiety such as GLA-27 and GLA-60 were reported to activate B cells and macrophages and to induce release of mediators including gamma interferon and tumor necrosis factor (TNF) at nontoxic doses (for a review, see reference 5). The analogs were also found to be active in enhancing host resistance to microbial and viral infections in normal and myelosuppressed mice (5-7). Synth...

Lipid X, a precursor in the biosynthesis of lipid A, has been claimed to possess most of the immunostimulatory activity but none of the toxicity of endotoxin. However, recent work shows that synthetic lipid X can be contaminated with small amounts of N,O-acylated disaccharide-1-phosphate (H. Aschauer, A. Grob, J.

Numerous lipid A analogs have been synthesized in an attempt to dissociate endotoxic activities from beneficial immunomodulatory activities. In the present study, we have evaluated select lipid A analogs in macrophages for their ability to induce a panel of lipopolysaccharide (LPS)-inducible genes to gain insights into the molecular mechanisms which underlie endotoxicity. We evaluated three monosaccharide lipid A analogs: SDZ MRL 953, an agonist with an improved therapeutic margin over endotoxin; SDZ 281.288, a more toxic analog; and SDZ 880.431, an analog with proven LPS-inhibitory activity. In addition, three disaccharide lipid A analogs (i.e., lipid IVA, SDZ 880.611, and SDZ 880.924) that differ in acylation and phosphorylation patterns were also examined and compared with synthetic lipid A. With the exception of SDZ 880.431, each of these structurally diverse analogs was able to induce the complete panel of LPS-inducible genes, specifically genes which encode tumor necrosis factor alpha (TNF-cx), interleukin-113, 75-kDa type 2 TNF receptor (D7), IP-10, D3, and D8. These results underscore that macrophage stimulation by lipid A analogs is permissive to considerable structural diversity. Structures with favorable therapeutic indices (SDZ MRL 953, SDZ 880.611,

The synthesis of a series of novel acyclic analogues of lipid A, the lipophilic terminal of lipopolysaccharide (LPS), is reported. In these compounds, the reducing glucose unit of lipid A has been replaced by an acyclic analogue unit (abbreviated as AAU) consisting of a spacer (of varying length), an (R)-3-hydroxytetradecanamido moiety (of varying configuration at the carbon of attachment), and a CO2H group. The AAU has been attached to the anomeric carbon of the nonreducing glucose unit of lipid A, either through glycosidic linkage or through an acyl linkage. Further, amide isosteres of these acyclic analogues have been prepared using suitably protected 2,3-diamino-2,3-dideoxyglucose instead of 2-amino-2-deoxyglucose. All the compounds were well characterized and were tested for their ability to induce TNF-alpha in mouse bone marrow-derived macrophages, to enhance nonspecific resistance to infection in mice and to induce endotoxic shock in mice. The results showed a dramatic dependence, for the first time, on the length of the spacer and on the configuration of the carbon bearing the amido group in the AAU part of the analogues.

VOL. XXXVIII NO. 2 THE JOURNAL OF ANTIBIOTICS CHEMICAL MODIFICATION OF AMIKACIN AT C-4" WITH INVERSION OF CONFIGURATION Sir: With the appearance of an aminoglycoside 4', 4"-nucleotidyl transferase,') selective modification of the clinical important amikacin (1) at these positions became of interest. Although enzymatic deactivation involving hydroxyl groups usually is overcome by "deoxygenation' 1,2) our efforts are focussed on the introduction of a substituent, which lacks ability to participate in a resistance mechanism but preserves the original polarity. At this time we wish to report on the synthesis and antibacterial activity of 4"-azido-4"-deoxy-4"-epi-amikacin (13) and 4"-deoxy-4"-fluoro-4"epi-amikacin (14). To trace the effect of the configurational change itself as well as that of fluorination, 4"-epi-amikacin (15) and 6"-deoxy-6"-fluoroamikacin (9) were also prepared. Starting from 1, protection of the amino functions with the tent-butoxycarbonyl (Boc) group by reaction with di-tert-butyl dicarbonate in DMSO-H_O (95: 5) for 6 hours at 60°C gave 3,6',3",4"'-tetra-N-Boc-amikacin3' (2) in 96 yield. Its treatment with chi orotriphenylmethane