Treatment of disseminated histoplasmosis in hamsters

A comparative study between itraconazole, ketoconazole and amphotericin B in the treatment of experimental histoplasmosis in hamsters was carried out.Seventy five animals were inoculated intracardiacally with the yeast-phase of Histoplasma capsulatum. They were divided in 5 groups: 1) treated with itraconazole by gavage (g) at a daily dose of 16 mg/kg; 2) treated with ketoconazole by (g) at a daily dose of 80 mg/kg; 3) treated with amphotericin B intraperitoneally (i.p.) at 6 mg/kg every other day; 4) control animals receiving distilled water i.p. and 5) control animals receiving P.E.G. 200 by (g). All the treatments were started one week after the challenge inoculation and they were given for 21 days. The results were evaluated by autopsy of all the animals one week after the end of the treatments. The following determinations were taken into account: microscopic examinations of spleen, liver and lungs and cultures of the spleen with determination of colony forming units/g.All the antifungal drugs used in this study were able to cause negative microscopic examinations of the liver, spleen and lungs; but only amphotericin B produced culture negative results. Itraconazole and ketoconazole presented 66% and 86% of positive cultures respectively, nevertheless the C.F.U. were lower than those obtained in control groups.In these experimental conditions amphotericin B seems to be more active than the azolic compounds and itraconazole is slightly superior to ketoconazole at a lower dose.     

THIS ARTICLE HAS BEEN RETRACTEDHamycin treatment of candidiasis in normal and diabetic rats

Hamycin, a heptaene antifungal antibiotic was compared with amphotericin B in the treatment of established systemic infection with Candida albicans in normal and diabetic rats. In normal rats, orally administered hamycin at 10 mg kg(-1) per day for 7 days reduced Candida colony counts in the kidneys and livers as well as amphotericin B did and was nearly as effective as amphotericin B in a 21-day treatment trial. There was no further reduction in Candida colony counts when normal rats were treated with hamycin at 25 mg kg(-1) twice a day for 7 days. In streptozotocin induced diabetic rats, hamycin at 20 mg kg(-1) per day for either 7 or 21 days compared favourably with amphotericin B in efficacy. Results of the present study suggest that oral hamycin may be useful in the treatment of established disseminated candidiasis in normal as well as diabetic hosts.     

Interruption of antifungal secondary prophylaxis in AIDS-related histoplasmosis

The clinical data of 21 patients, suffering AIDS-related histoplasmosis, who were able to interrupt antifungal secondary prophylaxis, after achieving a partial restoration of the cell mediated immunity by HAART administration, are presented. They were 16 males and five females, whose ages varied between 32 and 54 years (mean = 38.5 years). All of them presented disseminated progressive forms of histoplasmosis, with multiple locations (skin, mucous membranes, liver, spleen, lymph nodes and lungs). The majority of the cases suffered other concomitant diseases (specially tuberculosis and Kaposi sarcoma), 66.6 % of the patients had less than 50 CD4+ cells/microl at the start of treatment and the average viral burden was 278,385 RNA copies/ml. The initial treatment consisted in 400 mg/day of itraconazole, by oral route, in 14 cases and the remaining seven patients were treated with amphotericin B, intravenously, at a daily dose of 0.7 mg/kg of body weight. One patient who did not tolerate amphotericin B and presented a partial response to itraconazole, was treated with posaconazole orally at a daily dose of 800 mg. Fourteen patients received oral itraconazole at a daily dose of 200 mg as a secondary prophylaxis, the remaining three patients were treated with intravenous amphotericin B, 50 mg twice a week. After HAART for an average lapse of 16.7 months (10 to 32 months), five cases showed CD4+ cells counts above 150 cells/microl and the remaining 16 presented more than 200 cells/microl; 18 of them had undetectable viral burden and all cases were asymptomatic. The follow up after secondary prophylaxis discontinuation varied between six months and six years (mean= 33.6 months). Twenty out of 21 patients (95 %) were clinically stable, without any manifestation of relapses, including two patients who abandoned HAART. One patient, who discontinued HAART, contracted a fatal bacterial pneumonia. Even though the limited number of cases, the data presented in this study seem to suggest that it is possible to interrupt antifungal secondary prophylaxis of histoplasmosis, when the patient is clinically asymptomatic and the CD4+ cells counts are above 150 cells/microl.     

Azithromycin: antimalarial profile against blood- and sporozoite-induced infections in mice and monkeys

The spectrum of antimalarial activity of the new macrolide antibiotic azithromycin was evaluated against blood- and sporozoite-induced infections with a chloroquine-resistant strain of Plasmodium yoelii nigeriensis (N-67) in Swiss mice and with simian parasite Plasmodium cynomolgi B in rhesus monkeys. Against experimental rodent malaria, a 70 mg/kg/day dose showed curative blood-schizontocidal activity in a four-dose regimen administered orally from day 0 to day 3 or from day 2 to day 5 to mice harboring established infection. The curative response was also obtained with a 40 mg/kg/day dose administered in an extended seven-dose (days 0-6) regimen. Azithromycin was also effective in the causal prophylactic test, since a 50 mg/kg dose from day -1 to day +2 protected mice against P. y. nigeriensis (N-67) sporozoite challenge. In comparison, erythromycin did not show either of the above activities up to a 405 mg/kg/day dose in identical regimens. Comparison of the ED(90) values showed that azithromycin was 31-fold more effective than erythromycin as a blood schizontocide. In the simian model, trophozoite-induced infections of P. cynomolgi B were cured with 25 mg/kg/day azithromycin administered for 7 days. In the causal prophylactic test, the prepatent period was significantly extended in monkeys challenged with P. cynomolgi B sporozoites, presumably because of the growth inhibition of preerythrocytic schizonts in hepatocytes. Azithromycin did not exhibit any hypnozoitocidal (dormant exoerythrocytic stages) activity at 25 mg/kg/day in a seven-dose regimen.     

Complexes of Amphotericin B and Cholesteryl Sulfate

Abstract

To improve the clinical utility of amphotericin B, we have developed a novel formulation of amphotericin B, Amphocil® (also known as Amphotericin B Colloidal Dispersion, or ABCD). Amphocil is a uniform disc-shaped complex of amphotericin B and sodium cholesteryl sulfate in a molar ratio of 1:1. The complex has a mean hydrodynamic diameter of approximately 115 nm and is thermodynamically stable. In an extensive series of pharmacodynamic, pharmacokinetic and toxicology studies, Amphocil was found to be less toxic than conventional amphotericin B (Fungizone®), providing a four- to five-fold improvement in safety, while remaining effective in treating a variety of fungal infections. Plasma pharmacokinetics and tissue disposition of amphotericin B differ in several respects after administration of Amphocil and conventional amphotericin B, due to a rapid uptake of Amphocil by liver. Animals receiving Amphocil demonstrated reduced peak levels in plasma, prolonged residence time and lowered levels of amphotericin B in most tissues including the kidney, the major target organ for toxicity, compared with animals receiving conventional amphotericin B.

In healthy male subjects receiving a single dose of Amphocil, ranging from 0.25-1.5 mg/kg, mild to moderate dose-dependent acute side effects typically seen with conventional amphotericin B were observed but there was no sign of renal or hepatic toxicities. In two dose-escalating studies, multiple daily doses of Amphocil up to 4.5 mg/kg were well tolerated in patients who had previously failed to tolerate or respond to conventional amphotericin B. In addition, complete clearance of fungal infection was observed with the Amphocil therapy. Thus, Amphocil is a safe and effective agent for treating systemic mycoses. Toleration and efficacy of higher doses of Amphocil in patients with life-threatening mycoses is currently being evaluated.     

Comparative study of four antifungal drugs in an experimental model of murine cryptococcosis

A comparative study among amphotericin B, 5-fluorocytosine, itraconazole and fluconazole in the treatment of experimental cryptococcosis in mice, was carried out.Seventy male Balb C mice were inoculated intraperitoneally with 10⁷ cells of Cryptococcus neoformans var. neoformans. They were divided in 7 groups of 10 animals each one: 1) treated with fluconazole by gavage at a daily dose of 16 mg/kg; 2) treated with itraconazole by gavage at a daily dose of 16 mg/kg; 3) treated with 5-fluorocytosine by gavage at a daily dose of 300 mg/kg; 4) treated with amphotericin B intraperitoneally at a dose of 6 mg/kg every other day; 5) control animals receiving polietilenglicol 200 by gavage; 6) control animals receiving distilled water by gavage and 7) control animals receiving sterile distilled water by intraperitoneal route. All the treatments started 5 days after the challenge inoculation and they were given for 2 weeks.The following parameters were taken into account: survival time, macroscopic aspect of the organ after the complete autopsy, microscopic investigation of yeasts in brain, lungs, spleen and liver, histopathology studies of these organs, the colony forming units per gram and massive seeding of brain and lungs.The survival index of the different groups was the most efficient method to measure the antifungal compounds activity. Amphotericin B increased significantly the animals survival and modified the histopathologic response in the studied organs. The colony forming units and the massive seeding in brain and lung showed that this antifungal agent is unable of producing the biological cure of this experimental model.The remaining drugs assayed did not promote important modifications in the histopathologic picture as well as in the tissues cultures. However, the three drugs increased the animals survival. In this aspect, fluconazole proved to be slightly superior.     

Cochleates: New Lipid-Based Drug Delivery System

Abstract

Cochleates are a lipid-based tailored drug delivery system formed by the precipitation of a negatively charged lipid and a cation, for example phosphatidylserine and calcium. Hydrophobic, amphiphilic, negatively or positively charged moieties are suitable candidates to be delivered via cochleates. Various procedures have been developed allowing the control of cochleate particle size, including the trapping and hydrogel methods, which use either a direct addition or a slow diffusion of calcium into the negatively charged liposome/drug suspension. The efficacy of cochleates to encapsulate and deliver drugs was evaluated using amphotericin B as a model. Amphotericin B cochleates (CAMB) were compared to Fungizone® and AmBisome®, two commercially available AmB products. Parenterally, CAMB was given IP to ICR mice infected with Candida albicans. 100% survival was observed with low doses of CAMB (0.5 mg/kg/day, 10 days) compared to 60% for Fungizone, at the same dose. Tissue burden studies were conducted in parallel. Mice were treated daily from day 1 to day 7 post challenge and tissue burden assessed at day 8. In the kidneys, all three formulations were comparable in reducing colony counts. In the spleen, CAMB at 10 mg/kg/day was comparable to AmBisome given IV at the same dose. At 1 mg/kg/day, CAMB was more potent than Fungizone and AmBisome. Oral administration of CAMB in C57BL/6 mice, at 10 mg/kg results in high levels of AmB in target tissues. Multiple daily doses (10) showed accumulation of AmB in key tissues (liver, lungs, spleen, and kidneys) and AmB tissue concentrations are raised to therapeutic levels. Orally administered CAMB are highly effective against fungal infections in mice at very low doses. Balb/C mice were infected with Candida albicans and were given oral CAMB as a daily dose for 15 days. Comparison was done to AmBisome given orally at 10 mg/kg and Fungizone IP. 100% survival was obtained with CAMB at doses as low as 0.5 mg/kg/day (15 days). CAMB eradicate Candida from lungs when given at 2.5 mg/kg/day and was comparable to Fungizone given IP at almost the same dose (2 mg/kg/day). The comparison between CAMB and AmBisome shows that oral CAMB is 10 times more effective than oral AmBisome in reducing colony counts in both kidneys and lungs. Orally administered CAMB were non-toxic even at the highest dose of 50 mg/kg/day (14 days). This was demontrated by 100% survival of the animals and normal histopathology analysis. No lesions in the kidneys, GI tract, lungs, liver and spleen was observed despite the substantial amount of AmB in these organs. AmB cochleate promise to be a safe, broad spectrum, effective and orally available, antifungal formulation.     

环磷酰胺诱导小鼠血小板减少症模型的建立(英文）

比较由环磷酰胺两种不同给药方式诱导小鼠血小板减少症模型的效果,并对效果较稳定的一种给药方式进行最佳造模剂量摸索,以期确定一个造模效果较好,毒副作用较低,利于观察治疗药物疗效的血小板减少症模型。模型A组,第1天尾静脉注射环磷酰胺200 mg/kg,然后连续6 d,每天1次以维持剂量30 mg/kg腹腔注射环磷酰胺。模型B组,按150 mg/kg皮下注射环磷酰胺,每天1次,连续3 d。结果显示模型B组造模效果较好,故以模型B组给药方法进行剂量摸索实验。由第7天的血小板计数可知环磷酰胺低（100 mg/kg）、中（120 mg/kg）、高（140 mg/kg）剂量均可引起血小板减少症,而低剂量组与其他组比较有高效低毒的特点,更有利于观察治疗药物的作用,可用于具有升血小板作用药物的药效学研究     

Comparative efficacy of fluconazole and amphotericin B in the parenteral treatment of experimental paracoccidioidomycosis in the rat

Patients with severe and complicated paracoccidioidomycosis are treated with amphotericin B by the intravenous route. Fluconazole is active in vitro against Paracoccidioides brasiliensis and can also be administered intravenously, but few clinical or experimental data are available about its action against the infection caused by this fungus. In the present study, the efficacy of fluconazole andamphotericin B was assessed comparatively in rats inoculated parenterally with P. brasiliensis. The treatment was performed 3 times a week for 4 weeks starting one week after infection. Fluconazole administered intraperitoneally (14 mg/kg bodyweight/dose) was more effective (P > 0.001)than amphotericin B (2 mg/kg body weight/dose) in reducing the number of colony forming units in the lungs and spleen. When administered intravenously at the dose of 3 mg/kg body weight, fluconazole was as effective as amphotericin B (0.8 mg/kg body weight) in reducing the pulmonary fungal burden. Under these conditions, the rats treated with fluconazole had a smaller number of colony forming units than untreated animals (P > 0.001), but amphotericin B was more effective than fluconazole in reducing spleen infection (P > 0.005). Except for this result obtained with a low dose, fluconazole showed an antifungal action equal to or higher than that of amphotericin B. The activity of fluconazole at doses equivalent to those used for human treatment suggests that this antifungal agent may be an alternative to amphotericin B for the early intravenous treatment of patients with paracoccidioidomycosis. This revised version was published online in June 2006 with corrections to the Cover Date.     

Evaluation of Systemic Antifungal Agents in X-Irradiated Mice

The effect of X irradiation on the survival time of animals experimentally infected with pathogenic fungi was studied, and the activity of antifungal agents in pre-irradiated hosts was evaluated. A 24-hr preinfection dose of X irradiation decreased the survival time of mice infected with Cryptococcus neoformans and Histoplasma capsulatum to a greater extent than Candida albicans or Blastomyces dermatitidis infections. Exposure to 400 r caused a significant reduction in the variation (S(2)) survival time of C. albicans or H. capsulatum mouse infections. A single 100-mg/kg dose of 5-fluorocytosine or amphotericin B administered within 24 hr postinfection significantly extended the survival time of mice infected with C. albicans. Delayed treatment with amphotericin B was effective against C. neoformans infections. Four 50-mg/kg doses of 5-fluorocytosine were more effective than a single 200-mg/kg dose against C. neoformans infections. A single dose of amphotericin B provided significant protection when administered 48 hr postinfection against B. dermatitidis in preirradiated mice. A single dose of saramycetin 48 hr postinfection was highly effective against H. capsulatum mouse infections. A 100-mg/kg dose of amphotericin B was only effective against this fungal pathogen when administered within 8 hr postinfection. In vivo activity of the antifungal agents studied was detected within 8 to 14 days. The relative in vivo activity of several antifungal agents indicated the importance of considering their individual pharmacological properties for optimum effectiveness. The experimental model used in this study should be useful for the detection and for the preclinical evaluation of new antifungal agents.     

Utilidad clínica de la micafungina en el tratamiento de las candidiasis invasoras en el paciente oncohematológico

BackgroundInvasive candidiasis is a severe infection among onco-hematological patients, with an attributable mortality around 40%. Micafungin has shown efficacy in antifungal prophylaxis among hematopoietic stem cell transplant recipients and in the treatment of esophageal candidiasis.AimsTo assess the role of micafungin in the treatment of invasive candidiasis among onco-hematological patients.MethodsLiterature review.ResultsIn a study on 126 patients with candidemia treated with micafungin, an overall response rate of 83% was reported. A double-blind study of 531 patients with invasive candidiasis comparing micafungin (100 mg/day) versus liposomal amphotericin B (3 mg/kg/day) reported success in 90% of patients in both arms, with a more favorable safety profile with micafungin. Other double blind randomized, phase III study compared two doses of micafungin (100 mg/day and 150 mg/day) with standard doses of caspofungin (70 mg loading dose, then 50 mg/day) in adults with invasive candidiasis. Overall success rate was 74% for micafungin 100 mg/day, 70% for micafungin 150 mg/day, and 71% for caspofungin. A double blind randomized study compared micafungin (2 mg/kg/day) to liposomal amphotericin B (3 mg/kg/day) in the treatment of invasive candidiasis in children with a predominance of infections with non-albicans Candida spp. Overall success rate was similar (73% for micafungin and 76% for liposomal amphotericin B).ConclusionsComparative phase III studies have demonstrated non-inferiority of micafungin compared to standard antifungal agents for invasive candidiasis. Micafungin is safe and effective in the treatment of children and adults with invasive candidiasis. Effectivity in invasive infections caused by non-albicans Candida spp is especially relevant in onco-hematological patients receiving fluconazole prophylaxis.     

Concomitant antagonism of endothelial and vascular smooth muscle cell ETB receptors for endothelin induces hypertension in the hamster

In the vascular system, endothelin (ET) type B (ET(B)) receptors for ET-1 are located on endothelial and on venous and arterial smooth muscle cells. In the present study, we investigated the hemodynamic effects of chronic ET(B) receptor blockade at low and high doses in the Syrian Golden hamster. After 16 days of gavage with A-192621 (0.5 or 30 mg.kg(-1).day(-1)), a selective ET(B) receptor antagonist, hamsters were anesthetized with a mixture of ketamine and xylazine (87 and 13 mg/kg im, respectively), and basal mean arterial blood pressure (MAP) and pressor responses to exogenous ET-1 were evaluated. The lower dose of A-192621 (0.5 mg.kg(-1).day(-1)) did not modify basal MAP, whereas the higher dose (30 mg.kg(-1).day(-1)) increased MAP and plasma ET levels. Radio-telemetry recordings confirmed the increase in MAP induced by the higher dose of A-192621 in conscious hamsters. On the other hand, although the lower dose of A-192621 was devoid of intrinsic pressor effects, it markedly reduced the transient hypotensive phase induced by intravenously injected IRL-1620, a selective ET(B) receptor agonist. Finally, A-192621 (0.5 mg.kg(-1).day(-1)) alone or A-192621 (30 mg.kg(-1).day(-1)) + atrasentan (6 mg.kg(-1).day(-1)), a selective ET(A) receptor antagonist, potentiated the pressor response to exogenous ET-1. Our results suggest that, in the hamster, ET(B) receptors on vascular smooth muscle cells are importantly involved in the clearance of endogenous ET-1, whereas the same receptor type on the endothelium is solely involved in the vasodilatory responses to the pressor peptide. Blockade of endothelial and vascular smooth muscle cell ET(B) receptors triggers a marked potentiation of ET(A)-dependent increases in systemic resistance.     

In vitro and in vivo antifungal activities of liposomal amphotericin B,and amphotericin B lipid complex

The in vitro and in vivo antifungal activities of liposomal amphotericin B (L-AMPH) and amphotericin B lipid complex (ABLC), which is composed of amphotericin B and the phospholipids dimyristoyl phosphatidylcholine and dimyristoyl phosphatidylglycerol, were compared with those of conventional amphotericin B (Fungizone®, AMPH). The acute intravenous toxicity was markedly lower in BALB/c mice; 50% lethal doses (LD_50s) were 2.75 mg/kg in AMPH, 32.9 mg/kg in L-AMPH and >75 mg/kg in ABLC. In vitro antifungal activities againstCandida albicans, C. parapsilosis, C. tropicalis, C. glabrata, andC. krusei were evaluated by the agar plate dilution method. The activities were unchanged againstC. albicans, but MICs increased more than four fold in 18 of the 20 strains other thanC. albicans in L-AMPH and in 9 of the 20 in ABLC. L-AMPH and ABLC were as efficacious as AMPH in the treatment of mice infected withC. albicans, and at a dose of 0.5 and 1.0 mg/kg of body weight, ABLC was more efficacious on survival. A ten-times larger dose (10 mg/kg) of L-AMPH and ABLC was administered to mice with 100% survival, suggesting improved tolerability as compared to amphotericin B.     

Study of trans-placental transport of methylamphotericin B in albino rats after intravenous administration]

Transplacental penetration of amphotericin B, an methyl derivative, was studied on rats after its intravenous administration. Microbiological and radioisotopic methods were used. When the microbiological method was applied the drug was administered on days 16 to 20 or on day 20 of pregnancy in a dose of 4 mg/kg. For extraction of the antibiotic dimethylformamide was added to the substrates. The labeled antibiotic was administered in a dose of 3.3 mg/kg on days 6 to 16 and on day 20 of pregnancy. It was noted that the antibiotic accumulated in the placenta. The accumulation was more pronounced after antibiotic use in the course doses. A significant part of the antibiotic was in the placenta in the bound state. The methyl derivative amphotericin B was not detected microbiologically in the umbilical cord serum, fetal organs and amniotic fluid. Neither was it detected by extraction with ++dimethylformamide. The labeled antibiotic was neither detected in the amniotic fluid and fetal organs during the whole observation period. Therefore, the methyl derivative amphotericin B did not penetrate through the placental barrier either in the free or bound state. The direct teratogenic action of amphotericin B, a methyl derivative, after its intravenous administration to female rats is likely possible.     

Study of embryotoxic and teratogenic effects of amphotericin B and a methyl derivative of amphotericin B in rats after their intravenous and intra-amniotic administration]

The embryotoxic action of amphotericin B and its methyl derivative was compared in rats after their intravenous and intraamniotic administration. The concentrations of amphotericin B and its methyl derivative in the amniotic cavity on days 13, 14 and 15 of pregnancy were 1.5 and 36 micrograms/ml, respectively. When administered intravenously during the preimplantation period the antibiotics had no embryotoxic action. Intravenous administration of amphotericin B in a dose of 500 micrograms/kg and its derivative in a dose of 2000 micrograms/kg during organ genesis induced a decrease in the craniocaudal size. In a dose of 3000 micrograms/kg administered intravenously the methyl derivative of amphotericin B induced an increase in postimplantation death rates. Administration of amphotericin B to the amniotic cavity had no damaging action. Administration of the methyl derivative on day 15 of pregnancy led to anomalous development of the lower extremities and slower ossification. The threshold doses by the embryotoxic action for intravenous administration are 500 micrograms/kg for amphotericin B and 2000 micrograms/kg for the methyl derivative. Administration of the antibiotics to the amniotic cavity revealed potential teratogenic properties of the amphotericin B methyl derivative.     

Combination Efficacy of Voriconazole and Amphotericin B in the Experimental Disease in Immunodeficient Mice Caused by Fluconazole-resistant <Emphasis Type="Italic">Cryptococcus neoformans</Emphasis>

The therapeutic efficacy of amphotericin B and voriconazole alone and in combination with one another were evaluated in immunodeficient mice (BALB/c-SCID) infected with a fluconazole-resistant strain of Cryptococcus neoformans var. grubii. The animals were infected intravenously with 3 × 10⁵ cells and intraperitoneally treated with amphotericin B (1.5 mg/kg/day) in combination with voriconazole (40 mg/kg/days). Treatment began 1 day after inoculation and continued for 7 and 15 days post-inoculation. The treatments were evaluated by survival curves and yeast quantification (CFUs) in brain and lung tissues. Treatments for 15 days significantly promoted the survival of the animals compared to the control groups. Our results indicated that amphotericin B was effective in assuring longest-term survival of infected animals, but these animals still harbored the highest CFU of C. neoformans in lungs and brain at the end of the experiment. Voriconazole was not as effective alone, but in combination with amphotericin B, it prolonged survival for the second-longest time period and provided the lowest colonization of target organs by the fungus. None of the treatments were effective in complete eradication of the fungus in mice lungs and brain at the end of the experiment.     

Unequal Day-Night Terbutaline I.V. Dosing in Acute Severe Asthma: Effect on Nocturnal Bronchial Patency, Heart Rate, and Arterial Pressure

Our study investigated the differential effects of continuous or unequal day-night terbutaline dosing on circadian bronchial patency, heart rate, and arterial pressure in severe acute asthma. Forty-five hospitalized asthmatic patients (19 women and 26 men, mean age 45.4 years, mean weight 63.5 kg) were included in this multicenter study. Three groups of patients (corresponding to three dosing schedules) were randomized; the three groups were comparable, since no statistically significant difference was detected in the age, weight, or peak expiratory flow values at the beginning of the study. In order to reach immediately the concentrations of terbutaline corresponding to the desired unequal day-night concentrations, a theoretical pharmacokinetic simulation was done to predict the outcome in terms of the plasma concentrations after the three dosing regimens; the results of this simulation allowed us to calculate the initial bolus dose to be given over 5 min to groups A, B, and C, i.e., 1.47, 2.94, and 4.41 Mg/kg, respectively. This bolus was given to all patients at 0700 h, the beginning of the study. The patients were randomly divided into three groups (A, B, C) receiving one of these treatments: 0.0111 mg/kg of terbutaline i.v. from 0700 to 1900 h at a constant rate delivered by an electrical pump and 0.0222 mg/kg of terbutaline i.v. from 1900 to 0700 h at a constant rate (A) (one third the total daily dose during the day and the remaining two thirds at night), 0.0166 mg/kg of terbutaline i.v. from 0700 to 1900 h at a constant rate and 0.0166 mg/kg of terbutaline i.v. from 1900 to 0700 h at a constant rate (B) (one half the total daily dose during the day and the remaining one half at night), or 0.0222 mg/kg of terbutaline i.v. from 0700 to 1900 h at a constant rate and 0.0111 mg/kg of terbutaline i.v. from 1900 to 0700 h at a constant rate (C) (two thirds the total daily dose during the day and the remaining one third at night). Since acute severe asthma could not be treated without steroids, a 40 mg dose of SoluMedrol was injected into all patients at 0700. Peak expiratory flow rate, heart rate, systolic arterial pressure, and possible side effects were recorded at different times during the 24-h scale: 0700, 1000, 1300, 1600, 1900, 2300, 0300, and 0700 h. Our results have shown a significant therapeutic effect of terbutaline i.v. dosing in severe acute asthma whatever the unequal daynight dosing, but did not demonstrate the efficacy of one of the three dosing schedules over the others.     

Unequal Day-Night Terbutaline I.V. Dosing in Acute Severe Asthma: Effect on Nocturnal Bronchial Patency,Heart Rate,and Arterial Pressure

Our study investigated the differential effects of continuous or unequal day-night terbutaline dosing on circadian bronchial patency, heart rate, and arterial pressure in severe acute asthma. Forty-five hospitalized asthmatic patients (19 women and 26 men, mean age 45.4 years, mean weight 63.5 kg) were included in this multicenter study. Three groups of patients (corresponding to three dosing schedules) were randomized; the three groups were comparable, since no statistically significant difference was detected in the age, weight, or peak expiratory flow values at the beginning of the study. In order to reach immediately the concentrations of terbutaline corresponding to the desired unequal day-night concentrations, a theoretical pharmacokinetic simulation was done to predict the outcome in terms of the plasma concentrations after the three dosing regimens; the results of this simulation allowed us to calculate the initial bolus dose to be given over 5 min to groups A, B, and C, i.e., 1.47, 2.94, and 4.41 Mg/kg, respectively. This bolus was given to all patients at 0700 h, the beginning of the study. The patients were randomly divided into three groups (A, B, C) receiving one of these treatments: 0.0111 mg/kg of terbutaline i.v. from 0700 to 1900 h at a constant rate delivered by an electrical pump and 0.0222 mg/kg of terbutaline i.v. from 1900 to 0700 h at a constant rate (A) (one third the total daily dose during the day and the remaining two thirds at night), 0.0166 mg/kg of terbutaline i.v. from 0700 to 1900 h at a constant rate and 0.0166 mg/kg of terbutaline i.v. from 1900 to 0700 h at a constant rate (B) (one half the total daily dose during the day and the remaining one half at night), or 0.0222 mg/kg of terbutaline i.v. from 0700 to 1900 h at a constant rate and 0.0111 mg/kg of terbutaline i.v. from 1900 to 0700 h at a constant rate (C) (two thirds the total daily dose during the day and the remaining one third at night). Since acute severe asthma could not be treated without steroids, a 40 mg dose of SoluMedrol was injected into all patients at 0700. Peak expiratory flow rate, heart rate, systolic arterial pressure, and possible side effects were recorded at different times during the 24-h scale: 0700, 1000, 1300, 1600, 1900, 2300, 0300, and 0700 h. Our results have shown a significant therapeutic effect of terbutaline i.v. dosing in severe acute asthma whatever the unequal daynight dosing, but did not demonstrate the efficacy of one of the three dosing schedules over the others.     

Voriconazole, Combined with Amphotericin B, in the Treatment for Pulmonary Cryptococcosis Caused by C. neoformans (Serotype A) in Mice with Severe Combined Immunodeficiency (SCID)

Cryptococcosis is a subacute or chronic systemic mycosis with a cosmopolitan nature, caused by yeast of the genus Cryptococcus neoformans. The model of systemic cryptococcosis in mice with severe combined immunodeficiency (SCID) is useful for immunological and therapeutic study of the disease in immunodeficient hosts. Amphotericin B, fluconazole and flucytosine are the drugs most commonly used to treat cryptococcosis. Voriconazole is a triazole with high bioavailability, large distribution volume, and excellent penetration of the central nervous system. The objective of this study was to evaluate treatment with amphotericin B (AMB), voriconazole (VRC), and AMB, used in combination with VRC, of experimental pulmonary cryptococcosis in a murine model (SCID). The animals were inoculated intravenously (iv) with a solution containing 3.0 × 10(5) viable cells of C. neoformans ATCC 90112, (serotype A). Treatments were performed with amphotericin B (1.5 mg/kg/day), voriconazole (40.0 mg/kg/day) and AMB (1.5 mg/kg/day) combined with VRC (40.0 mg/kg/day); began 1 day after the initial infection; were daily; and lasted 15 days. Evaluations were performed using analysis of the survival curve and isolation of yeast in the lung tissue. There was a significant increase in survival in groups treated with AMB combined with VRC, compared with the untreated group and groups receiving other treatments (P < 0.05). In the group treated only with VRC and AMB combined with VRC, there was a significant reduction (P < 0.05) in the isolation of C. neoformans in lung tissue. Amphotericin B combined with voriconazole may be an effective alternative to increasing survival and may reduce yeast in the lung tissue of mice with pulmonary cryptococcosis and SCID.     

Chiral cyclopalladated complexes derived from N,N-dimethyl-1-phenethylamine with bridging bis(diphenylphosphine)ferrocene ligand as inhibitors of the cathepsin B activity and as antitumoral agents

Chiral cyclopalladated complexes derived from N,N-dimethyl-1-phenethylamine and the coordinating ligand 1,1'-bis(diphenylphosphine)ferrocene were synthesized and studied as Cathepsin B inhibitors and antitumoral agents against solid tumors. Our results revealed that the palladium compound [Pd2(C2,N-S(-)dmpa)2(mu-dppf)Cl2] (2) was able to inhibit Cathepsin B activity in a reversible fashion. This palladacycle compound binds to free cathepsin B (E) as well as to the enzyme-substrate complex (ES) with dissociation constants of KH=12+/-1 microM and alphaKH=2.4+/-0.3 microM, respectively. The application of this complex, in Walker tumor-bearing rats, resulted in 90% inhibition of the tumor growth. Subcutaneous inoculations of 10(6) tumoral cells produced solid tumors with a mass of 4.0+/-1.0 g in 12 days Walker tumor-bearing rats. However, when these animals were treated with one dose of the palladacycle compound (2.0 mg/kg), the tumoral mass was reduced to 0.3+/-0.1 g. On the other hand, the same complex (2) did not afford any protection to mice bearing the non-metastatic Ehrlich Ascites tumor treated with doses of 0.5, 5.0, and 30 mg/kg for a period of four, three and one day, respectively, beginning 72 h after tumor inoculation. Toxicological studies using mice treated with one high dose of the complex (2) (100 mg/kg) did not show any alterations in red and white blood cell morphology 14 days after the drug administration. Similar results were obtained with hepatic, kidney, and spleen tissues. The results presented in this work introduce the title cyclopalladated complexes as promising antitumoral drugs with reduced toxicity in experimental studies.