Structural features of aminoquinolines necessary for antagonist activity against botulinum neurotoxin

Certain aminoquinoline antimalarial compounds, such as chloroquine, antagonize the paralytic actions of botulinum neurotoxins (BoNT). These studies have been extended to determine the critical structural groups necessary for synthetic aminoquinolines to have antagonist activity against BoNT. Isolated mouse hemidiaphragms were maintained at 36 degrees C and indirectly stimulated; the resulting isometric twitch tensions were recorded as a measure of synaptic function. The muscles were exposed to the test compounds before being treated with a challenge concentration of BoNT (typically 0.2 nM of serotype A). The time to onset of 50% muscle paralysis due to BoNT was used to assess quantitatively the efficacy of the test compounds, which were then ranked on the basis of the concentrations necessary to delay paralysis by a specified time increment. Of the compounds tested, those having a 7-chloro-4-aminoquinoline configuration, similar to chloroquine (or the structurally similar 6-chloro-9-amino acridine group in quinacrine), were most effective. Truncation of the alkyl-amino-alkyl group from chloroquine and conversion of the 4-amino nitrogen to a primary amine did not significantly alter its effectiveness as a BoNT antagonist. However, the 6-chloro- or 8-chloro- isomers of chloroquine were essentially ineffective. These results suggest that aminoquinolines antagonize the paralytic actions of BoNT through interaction with a selective, stereospecific site that is not well correlated with antimalarial activity.     

Activity of N-chlorotaurine against herpes simplex- and adenoviruses

Monoclonal antibodies (MAbs) are being widely used for imaging studies, coupled mainly with 99mTc. The antibody ior egf/r3 is a MAb against human epidermal growth factor receptor (hEGF-r), and we have developed a method for optimum labeling of this MAb with 99mTc. The reduction was performed with 2-mercaptoethanol (2-ME) at a molar ratio of 2000:1 (2-ME:MAb) and methylene diphosphonate as transchelant. The integrity of reduced MAb was checked by mean of native polyacrylamide gel electrophoresis (PAGE) and gel filtration chromatography on Superose 12 (purity >99%). Radio colloids remained lower than 2%, and the labeling efficiency was 98.5%. The number of sulfhydryl groups generated was quantified using Ellman's reagent and was found to be 6.65+/-0.69 per antibody molecule. In vitro stability studies in several challenging conditions (DTPA, human serum albumin and human serum) were performed, and no significant loss in binding percentage was seen. Radio receptor assay was used to test immunoreactivity of the reduced MAb. Both labeled and unlabeled MAbs were able to compete for binding to the hEGF-r with radioiodinated EGF. Biodistribution studies in BALB/c mice are reported.     

食用真菌对大蒜素的敏感性测定

[目的]测定食用真菌营养繁殖体对大蒜素生物杀菌剂、防腐剂、保鲜剂的敏感性.[方法]采用组织分离法培养香菇(Lentinulaedodes)、平菇(Pleurotus ostreatus)、姬菇(Pleurotus cornucopiae)菌丝体,以水浸提法和乙醇萃取法制备大蒜素,依据生长速率法、改良管碟法分别在平板上测定供试真菌对大蒜素的敏感性.[结果]5、10、20 mg/ml大蒜素对香菇抑菌率分剐为67.2%、74.6%、78.4%;对平菇抑菌圈直径为28.0～35.7 mm,对姬菇抑菌圈直径为30.7～39.7 mm.[结论]供试真菌菌丝体生长受大蒜素的抑制,提示食用菌栽培不适合采用大蒜素防治病害或杂菌污染,但可尝试研制蘑菇子实体的大蒜素防腐剂、保鲜剂.     

Activity of disinfectants against vancomycin-resistant Enterococcus faecium

Myospherulosis is a chronic inflammatory reaction to the mixture of red blood cells and petroleum based ointments. A literature review does not reveal any cases involving ophthalmic manifestations. We present the first reported case of a patient experiencing recurrent eyelid inflammation from myospherulosis after endoscopic sinus surgery. The pathophysiology and management of myospherulosis are discussed.     

Specific activities of dolastatin 10 and peptide derivatives against Cryptococcus neoformans

The biosynthetic peptide dolastatin 10 is currently in phase I and II cancer clinical trials. We evaluated the antifungal spectrum of dolastatin 10 and four structural modifications. In broth macrodilution assays, the peptides were fungicidal for American Type Culture Collection strains and clinical isolates (including fluconazole-resistant strains) of Cryptococcus neoformans but no other yeasts or filamentous fungi examined. Specificity for C. neoformans was also demonstrated in the solid-phase disk diffusion assay, and fungicidal activity was confirmed in time-kill experiments. For a methyl ester modification, the MICs at which 50 and 90% of 19 clinical isolates were inhibited (MIC50 and MIC90, respectively) were 0.195 and 0.39 microg/ml, respectively. The MFC50 (50% minimum fungicidal concentration) for this peptide was 0.39 microg/ml, and the MFC90 was 0.78 microg/ml. MICs and MFCs were identical or lower in the presence of human serum but increased with lowered pH. These peptides should be pursued as potential chemotherapeutics for C. neoformans, a leading cause of infection and mortality in immunocompromised patients.     

Activity of cefamandole and other cephalosporins against aerobic and anaerobic bacteria

The activity of cefamandole was comparable to that of cephalothin, cefazolin, and cephaloridine against Staphylococcus aureus, Streptococcus pyogenes, and Diplococcus pneumoniae. In contrast, cefamandole was considerably more active than cephalothin, cefazolin, or cephaloridine against gram-negative facultative bacilli, including Haemophilus influenzae, the most striking disparities being noted with indole-positive Proteus and Enterobacter. Bacteroides fragilis was more susceptible to cefoxitin than to cefamandole or cefazolin (median minimal inhibitory concentration, approximately 8, 32, and 32 mug/ml, respectively); cephalothin exhibited still less activity against this species. The majority of other anaerobes were inhibited by relatively low concentrations of all four cephalosporins. The results indicate a potentially valuable role for cefamandole against facultative gram-negative bacilli, including H. influenzae, but no exceptional activity against anaerobes.     

Activity of two doses of rifampin against Mycobacterium leprae

In the course of a clinical trial designed to re-examine the bactericidal efficiency of 600-mg doses of rifampin (RMP) against Mycobacterium leprae, two doses of RMP, either 600 mg or 1200 mg, were administered 28 days apart to 29 previously untreated patients with lepromatous or borderline leprosy. Seven, 28, and 35 days after the start of the trial, skin biopsies were performed and immunologically normal mice were inoculated with 5 x 10(3) or 10(4) M. leprae in each hind foot pad. The patients assigned to the two regimens did not differ significantly in terms of sex, age, disease classification, bacterial index, or the concentration of M. leprae in the skin lesion biopsied for the inoculation of mice. The concentrations of organisms in the skin-biopsy specimens did not change significantly over the course of the trial among the patients, whether they were being treated by the first or the second regimen. The M. leprae recovered from specimens obtained from 21 of the patients, before beginning treatment, multiplied in a majority of the mice inoculated. The results of mouse inoculation confirmed the rapid bactericidal effects of RMP against M. leprae: a single dose of RMP rendered the organisms obtained from all but two of the patients incapable of multiplying in mice. No significant difference was demonstrated between the two regimens, nor was an additional effect of the second dose of RMP observed.     

Synthesis of adenine derivatives and their activities against herpes virus in vitro

A series of 9-(N4-substituted acetaldehyde thiosemicarbazone) adenines were synthesized and evaluated for antiherpes virus activity. Compounds 4a-l were prepared by condensation of 9-(acetaldehyde) adenine(6) and the corresponding N4-substituted thiosemicarbazides (10). The antiviral effects of all compounds 4a-l were tested in vitro in primary rabbit kidney cell cultures infected with herpes simplex virus type 1 (HSV-1) and varicella-herpes zoster virus (VZV), and in primary human embryo cell cultures infected with herpes simplex virus type 2 (HSV-2). The results showed that the minimum inhibitory concentrations (MIC) of 4e and 4f for HSV-1 and VZV were 20, 40, 20 and 20 micrograms.ml-1, respectively, and other compounds were 200 micrograms.ml-1. For HSV-2, the MIC of all tested compounds were 300 micrograms.ml-1. We also evaluated the antiherpetic effect of 4e (and 4f) by combination with acyclovir (ACV) in the ratio of 1:1 in vitro. The MIC of the combined compounds were 2 micrograms.ml-1 for 4e and 6 micrograms.ml-1 for 4f, while their minimum cytotoxicities (MCC) in the cell were markedly reduced compared with the individual compounds.     

Activity of liposomal amphotericin B against experimental cutaneous leishmaniasis

The polyene antibiotic amphotericin B is currently a second-line treatment for visceral leishmaniasis (VL) and mucocutaneous leishmaniasis. Lipid-amphotericin B formulations with lower toxicity than the parent drug that were developed for the treatment of systemic mycoses have proved to be an effective treatment for VL, especially AmBisome, a small unilamellar negatively charged liposome. In vitro, free amphotericin B was three to six times more active than the liposomal formulation AmBisome against both Leishmania major promastigotes in culture and amastigotes in murine macrophages. In a BALB/c L. major model of cutaneous infection, liposomal amphotericin B administered once a day on six alternate days by the intravenous route produced a dose-response effect between 6.25 and 50 mg/kg. Liposomal amphotericin B administered subcutaneously close to a lesion had no significant activity. Free drug was ineffective at nontoxic doses. The results suggest that liposomal amphotericin B may be useful in the treatment of cutaneous leishmaniasis.     

Metabolic effects of thiopurine derivatives against human CCRF-CEM leukaemia cells

BACKGROUND and aims. To compare the metabolic effects induced by the anticancer drugs, 6-mercaptopurine (6-MP), 6-thioguanine (6-TG) and 6-methylmercaptopurine riboside (MMPR), which may inhibit the de novo biosynthesis of purine nucleotides or be mis-incorporated into DNA or RNA. METHODS: Leukaemia cells were grown in culture, exposed to a thiopurine and cell extracts were analyzed for NTPs, dNTPs, drug metabolites and P-Rib-PP. RESULTS: In leukaemia cells, 6-MP was converted to MPR-MP, thio-XMP, thio-GMP, thio-GDP and thio-GTP. Metabolites of 6-TG included thio-XMP, thio-GMP, thio-GDP and thio-GTP, while MMPR-MP was the only major metabolite of MMPR, MMPR (25 microM, 4 h) induced a 16-fold increase in P-Rib-PP and 6-MP (25 microM, 4 h) induced a delayed 5.2-fold increase. MPR-MP, thio-GMP and MMPR-MP are inhibitors of amido phosphoribosyltransferase from leukaemia cells with Ki values of 114 +/- 7.10 microM, 6.20 +/- 2.10 microM and 3.09 +/- 0.30 microM, respectively. CONCLUSION: The nucleoside-5'-monophosphate derivatives of the 3 thiopurines inhibit amido phosphoribosyltransferase in growing leukaemia cells but there is also an initial inhibition of the further conversion of IMP in the pathway. In growing cells, MMPR acts solely as an inhibitor of de novo purine biosynthesis while 6-TG and to a lesser extent, 6-MP, are converted to significant concentrations of di- and tri-phosphate derivatives which may have other mechanisms of cytotoxicity.     

Activity of four fluoroquinolones against 346 strains of enteric pathogens

Several surgical approaches have been reported for operative correction of complex or recurrent form of aortic coarctation. In this study we report our experience with extra-anatomic ascending-supraceliac abdominal bypass grafting for complicated form of aortic coarctation in 12 patients. All patients survived the operations, without late mortality. This type of surgical correction of complex or recurrent form of coarctation is a safe and effective procedure.     

Activity of the triazole SCH 56592 against disseminated murine coccidioidomycosis

SCH 56592 (SCH) is a new triazole antifungal with a broad spectrum of activity. In vitro susceptibility testing against five strains of Coccidioides immitis revealed MICs from 0.39 to 3.13 microg/ml and minimal fungicidal concentrations from 1.56 to 3.13 microg/ml. A murine model of systemic coccidioidomycosis was established in female CD-1 mice. Groups received either no treatment or oral therapy with fluconazole at 10 or 100 mg/kg of body weight; itraconazole at 10 or 100 mg/kg; SCH at 0.5, 2, 10, or 25 mg/kg; or its methylcellulose diluent alone. Therapy began 2 days postinfection and continued once daily for 19 days. Surviving mice were euthanized 49 days postinfection, and infectious burdens were determined by culture. All drugs were superior to no-treatment or diluent-treatment controls (P < 0.001) in prolonging survival but were not significantly different from one another. Itraconazole at 100 mg/kg was superior to fluconazole in reduction of CFU in the spleen, liver, and lung (P < 0.01 to 0.001). SCH at 0.5 mg/kg was superior to either fluconazole or itraconazole at 10 mg/kg in reduction of CFU in all three organs (P < 0.05 to 0.001). SCH at 2 mg/kg was not significantly different from itraconazole at 100 mg/kg in all three organs. SCH at 10 and 25 mg/kg was superior to either dose of fluconazole or itraconazole in all three organs (P < 0.05 to 0.001). In terms of reduction of CFU, SCH was > or = 200-fold as potent as fluconazole and > or = 50-fold as potent as itraconazole. There was a clear dose-responsive relationship for SCH in each of the organs. It is noteworthy that SCH effected cures (no detectable C. immitis in any organ) in 1 of 9, 6 of 10, or 9 of 9 surviving mice in animals given 2, 10, or 25 mg/kg, respectively. Neither fluconazole nor itraconazole cured any survivor. SCH has potent, fungicidal activity in vivo against C. immitis. It should be considered for clinical trials in patients with coccidioidomycosis.     

Dilution and storage of botulinum toxin

BACKGROUND: There has been an ongoing controversy as to the best dilution for botulinum toxin for use in cosmetic applications. Recommended dilutions have ranged from 1 ml per vial to 10 ml per vial. There has also been much discussion on the diluent, i.e., preserved versus unpreserved saline, to be used and on storage time of the material after dilution. OBJECTIVES: The objective of this paper is to examine the literature and experience of practitioners in the field to try to resolve some of the questions concerning dilution and storage of botulinum toxin. CONCLUSIONS: Although there is great variation in the dilutions adopted by various physicians, much of this is a matter of personal preference. It does seem to appear that most clinicians use a dilution near 2.5 to 3.0 ml per vial and three-quarters of them limit the storage of the diluted product to 1 week or less.     

Alkyl side-chain derivatives of sordaricin as potent antifungal agents against yeast

Sordarin (1) was converted to 5 and 6, which showed potent antifungal activity against yeast. A series of C1-C9 alkyl side-chain derivatives was prepared, from which it was found that the optimal activity occurred with C5. A comparison of side chains with different unsaturation showed that the cis-alkene was the most active. This result suggested that the folding of the side chains might be crucial for the optimal activity.     

Synthesis and evaluation of isatins and thiosemicarbazone derivatives against cruzain, falcipain-2 and rhodesain

While commercial isatins were practically inactive against the target proteases, thiosemicarbazone derivatives were found to be active. The most active compound from the series displayed an inhibitory IC(50) value of 1 microM against rhodesain. One thiosemicarbazone was found to be active against all three proteases with inhibitory IC(50) values of 10 microM or less. A combination of N-benzylation and appropriate substitution on the aromatic portion of the isatin scaffold was generally found to be beneficial especially against cruzain for ketone inhibitors.     

Antimicrobial activity of newly synthesized isothiocyanate derivatives against pathogenic plant microorganisms

Fifteen reaction products of isothiocyanates with cysteine, seven reaction products of isothiocyanates with 2,3-dimercapto-1-propanol, and four reaction products of isothiocyanates with sulfanilamide were synthesized. Their antimicrobial activity against pathogenic plant microorganisms was investigated.     

In vitro activity of artemisinin derivatives against African isolates and clones of Plasmodium falciparum

To evaluate the effect of intensive physical exercise on intraocular pressure (IOP) in 66- to 85-year-old subjects IOP was measured before and after a maximal bicycle ergometer test. The non-glaucomatous subjects comprised 85 males and 36 female athletes and 16 male and 22 female controls of corresponding age drawn from a population register. IOP was measured using a non-contact tonometer. The results indicated a decrease (> or = 2 mmHg) in 34% of the subjects, no change in 57% and an increase in 9%. The decrease was more pronounced in subjects with higher pre-test values. In all four subjects with a pre-test value above 22 mmHg a reduction from 4 to 11 mmHg was observed. The change in IOP during physical loading was not significantly associated with the intensity and duration of exercise test. Three of the 5 male subjects with diagnosed glaucoma and undergoing hypotensive medication, who were analyzed separately, also showed a reduction in IOP during loading. In the pre- or post-test values there were no differences between the athletes and controls, while women tended to have higher IOP values than men. It is concluded that physical loading has predominantly a moderating effect, if any, on IOP in elderly men and women.