ram1 gene, encoding a subunit of farnesyltransferase, contributes to growth, antifungal susceptibility to amphotericin B of Aspergillus fumigatus.

Farnesylation, which is catalyzed by farnesyltransferase, is an important posttranslational process. The function of farnesyltransferase has been previously explored in Cryptococcus neoformans and Candida albicans. Aspergillus fumigatus is an important human opportunistic fungal pathogen in immunocompromised patients. Here we discover the role of the ram1 gene, encoding the ß-subunit of farnesyltransferase in A. fumigatus, in the fungal growth and antifungal susceptibility. In this study the ram1 gene was disrupted using A. tumefaciens-mediated transformation. The morphology and radial growth of Δram1 were observed. Assays of disk diffusion and broth microdilution were used to determine the susceptibility of Δram1 mutant to commonly clinical used antifungals and the farnesyltransferase inhibitor manumycin A. Deletion of ram1 resulted in a reduced radial growth of A. fumigatus but did not affect the microscopic morphology. Δram1 showed increased susceptibility to the antifungal amphotericin B; however, its susceptibility to azoles and caspofungin was the same to that to the parental strain. Our data indicate that farnesyltransferase is a potential target for design new antifungal agents.

Eficacia y seguridad de posaconazol en pacientes adultos con mucormicosis y respuesta inadecuada o eventos adversos al uso de amfotericina B / Efficacy and safety of posaconazole in adult patients with mucormycosis and inadequate response or adverse events to the use of amphotericin B

INTRODUCCIÓN: El presente dictamen presenta la evaluación de tecnología de la eficacia y seguridad de posaconazol en pacientes adultos con mucormicosis con reacción adversa secundaria al uso de amfotericina deoxicolato (Cualquier RAM III - IV) o refractariedad. La mucormicosis es una Infección oportunista poco frecuente y potencialmente letal, causada por hongos pertenecientes al orden Mucorales. Su distribución es mundial y afecta fundamentalmente a individuos con inmunidad alterada en quienes puede ocasionar infecciones graves e incluso mortales, de presentación fulminante o lenta e insidiosa, por lo que se le considera una de las infecciones micóticas más letales en seres humanos. Al ser una enfermedad de alta mortalidad aún con los pacientes en tratamiento y ser una infección de muy baja prevalencia, existe muy escasa evidencia de calidad que respalde el tratamiento de mucormicosis con diferentes esquemas. El tratamiento actual se encuentra basado en Amfotericina B, sin embargo para los pacientes que presentan falla al tratamiento o que son intolerantes por eventos adversos, no existe una segunda línea definida. Es así, que en los últimos años posaconazol ha sido descrito como un medicamento de segunda línea de tratamiento para pacientes con mucromicosis refractarios a amfotericina B o con toxicidad por la misma. Así, la presente evaluación tiene el objetivo de analizar la evidencia que apoya el uso de posaconazol como segunda línea de tratamiento para mucormicosis en casos en los que no se tiene una adecuada respuesta a la primera línea de tratamiento. METODOLOGIA: Se realizó una estrategia de búsqueda sistemática de la evidencia científica con respecto a la eficacia y seguridad de posaconazol en pacientes adultos con mucormicosis (zygomicosis) y con respuesta inadecuada (eventos adversos que no permitan continuar con la terapia o falla al tratamiento) a amfotericina. Para la búsqueda primaria se revisó la información disponible por entes reguladoras y normativas como la Food and Drug Administration (FDA), y la Dirección General de Medicamentos y Drogas (DIGEMID). Posteriormente se buscaron Guías de Práctica Clínica a través de los metabuscadores: Translating Research into Practice (TRIPDATABASE), National Library of Medicine (Pubmed-Medline), The National Guideline Clearinghouse (NGC), y Health Systems Evidence (HSE). Finalmente, se realizó una búsqueda dentro de la información generada por grupos internacionales que realizan revisiones sistemáticas, evaluación de tecnologías sanitarias y guías de práctica clínica, tales como The Cochrane Library, The National Institute for Health and Care Excellence (NICE), The Canadian Agency for Drugs and Technologies in Health (CADTH), The Scottish Medicines Consortium (SMC), que a su vez fue complementada con una búsqueda en www.clinicaltrials.gov, para identificar estudios primarios en elaboración o que no hayan sido publicados aún. RESULTADOS: Tras la búsqueda bibliográfica se encontraron documentos que evaluaron la eficacia y seguridad de posaconazol con respecto a la eficacia y seguridad en pacientes adultos con mucormicosis y con respuesta inadecuada a amfotericina deoxicolato. CONCLUSIONES: En la presente evaluación de tecnología sanitaria no se ha encontrado evidencia directa de calidad que muestre que el posaconazol ofrece beneficios para los pacientes con diagnóstico de mucormicosis con eventos adversos serios al uso de Amfotericina B deoxicolato (AMB). Sin embargo, se ha identificado evidencia indirecta proveniente de revisiones de casos en las cuales el uso de posaconazol como terapia de rescate en mucormicosis ha sido beneficioso para los pacientes que no pueden recibir amfotericina y que no tienen más opción de tratamiento. Al ser la mucormicosis una infección que viene incrementando su incidencia en los últimos años, y además con una alta letalidad, es importante contar con herramientas para su rápido diagnostico y tratamiento. Los estudios presentados si bien no son de una alta calidad debido a la baja prevalencia de la enfermedad, posicionan a posaconazol como un tratamiento de rescate para pacientes con Mucormicosis que no tengan indicación para recibir o a continuar con terapia con Amfotericina deoxicolato debido a intolerancia al tratamiento o a eventos adversos al mismo. El costo y la via de administración podrían ser de beneficio para la elección del tratamiento de los pacientes con mucormicosis que en muchos casos son pacientes que cuentan con enfermedades o tratamientos de fondo que implican inmunidad comprometida. Además, en estos pacientes incrementar las vías de acceso endovenosa siempre significa un riesgo agregado de infecciones. Los especialistas infectólogos opinan que el uso de posaconazol en mucormicosis refractaria o con eventos adversos a amfotericina constituiría la única alternativa terapéutica disponible para los pacientes con dicho diagnóstico y en los que el anfotericina B no constituye más una alternativa por falta de respuesta, intolerancia o efectos adversos. Por lo expuesto, el Instituto de Evaluaciones de Tecnologías en Salud e Investigación - IETSI, aprueba, el uso de posaconazol para el manejo de los pacientes con diagnóstico de mucormicosis que hayan presentado eventos adversos o sean refractarios o intolerantes al uso de Amfotericina B Deoxicolato, según lo establecido en el Anexo 1. La vigencia del presente dictamen preliminar es de dos años. Dado que la evidencia que respalda este uso de posaconazol en la mucormicosis es aún limitada, se actualizará la evaluación de tecnología sanitaria tanto con nueva evidencia científica publicada como con los datos clínicos de los pacientes que hayan recibido este tratamiento bajo lo establecido en el presente dictamen preliminar. Esta información será tomada en cuenta para efectos de un nuevo dictamen al terminar la vigencia del presente. Al no encontrarse evidencia sólida que respalde el uso de posaconazol en menores de 13 años de edad, no se puede recomendar su uso en este grupo etário. Dado que la evidencia que respalda el uso de posaconazol es aún limitada, se establece que el efecto de posaconazol se evaluará con los datos de los pacientes que lo hayan recibido por el periodo de vigencia de este dictamen para determinar el impacto de su uso en los desenlaces de interés de este dictamen. Esta información será tomada en cuenta en la reevaluación de este medicamento para efectos de un nuevo dictamen al terminar la vigencia del presente Dictamen Preliminar.

Chain elongation analog of resveratrol as potent cancer chemoprevention agent.

Resveratrol is identified as a natural cancer chemoprevention agent. There has been a lot of interest in designing and developing resveratrol analogs with cancer chemoprevention activity superior to that of parent molecule and exploring their action mechanism in the past several decades. In this study, we have synthesized resveratrol analogs of compounds A-C via conjugated chain elongation based on isoprene unit retention strategy. Remarkably, cytotoxic activity analysis results indicated that compound B possesses the best proliferation inhibition activity for NCI-H460 cells in all the test compounds. Intriguingly, compound B displayed a higher cytotoxicity against human non-small cell lung cancer cells (NCI-H460) compared to normal human embryonic lung fibroblasts (MRC-5). Afterward, flow cytometry analysis showed that compound B would induce cell apoptosis. We further researched the action mechanism. When NCI-H460 cells were incubated by compound B for 6 or 9 h, respectively, the intracellular reactive oxygen species (ROS) level was enhanced obviously. With elevation of intracellular ROS level, flow cytometry measurement verified mitochondrial transmembrane potential collapse, which was accompanied by the up-regulation of Bax and down-regulation of Bcl-2. More interestingly, compound B increased the expression of caspase-9 and caspase-3, which induced cell apoptosis. Moreover, compound B arrested cell cycle in G0/G1 phase. These are all to provide useful information for designing resveratrol-based chemoprevention agent and understanding the action mechanism.

Predictive genomic biomarkers for drug-induced nephrotoxicity in mice.

The present study aimed to establish candidate biomarker genes for the early detection of nephrotoxicity in mice, with a particular focus on nephrotoxicity caused by polyene macrolides. Comprehensive gene expression changes were evaluated using microarrays in a mouse model in which acute nephrotoxicity was induced by amphotericin B deoxycholate, trade name Fungizone. The upregulated genes identified through microarray analysis of kidney tissue of Fungizone-treated mice included several genes that have been reported as nephrotoxicity biomarkers in rats, and 14 genes were selected as candidate nephrotoxicity biomarkers. The usefulness of these genes as nephrotoxicity biomarkers in mice was evaluated further through expression profiling under several experimental conditions using real time RT-PCR. Expression of genes encoding kidney injury molecule 1, lipocalin 2, tissue inhibitor of metalloproteinase 1, and secreted phosphoprotein 1 was highly upregulated by Fungizone, nystatin, natamycin, amphotericin B methyl ester, and liposomal amphotericin B, and their area under the ROC curve values were more than 0.95. These genes were more sensitive at detecting nephrotoxicity than traditional clinical chemistry and histopathology parameters. This study provides novel evidence that these nephrotoxicity biomarker genes identified are translatable to mice, and that they are useful for early and sensitive detection of nephrotoxicity.

Safety, tolerability and pharmacokinetics of intravaginal pentamycin.

BACKGROUND/AIMS: Intravaginal pentamycin is a polyene macrolide with a broad spectrum of antimicrobial activity and is effective in various forms of infectious vaginitis. We evaluated the safety, tolerability and pharmacokinetics of escalating doses of this product. METHODS: Nineteen healthy volunteers were randomized to receive double blind one of five doses of intravaginal pentamycin (3, 10, 30, 60 or 100 mg) or the corresponding dose of pentamycin vehicle daily for 6 days. Patients with symptomatic vaginitis received a single dose of 60 (n = 6) or 100 mg (n = 6) of intravaginal pentamycin. Safety and tolerability parameters were monitored throughout the study. Plasma concentrations of pentamycin were measured daily in the healthy volunteers and on the day of drug application in the patients. RESULTS: The most frequently reported adverse events were mild or moderate vaginal discharge and mild symptoms of vaginal irritation (mainly pruritus or burning sensation), which also occurred in women who applied the vehicle. No patient with symptomatic vaginitis reported treatment-related adverse events. The plasma levels of pentamycin were below the quantification limit in all samples. CONCLUSION: Intravaginal pentamycin does not cause adverse reactions compared with vehicle and is not absorbed through the intact or the inflamed vagina.

[Antifungals for systemic use]. / Antifúngicos para uso sistémico.

The treatment of systemic fungal infections has undergone changes in the last years as several new antifungal agents have come on the market. Because of the existence of these therapeutic alternatives, it is clear that not all fungal infections should be treated in the same manner; thus, the identification of fungal species and susceptibility testing are increasingly important. The emergence of strains resistant to antifungal agents has led to variations in the treatment guidelines between different geographical areas. Therefore, knowledge of the properties, mechanisms of action, and activity profile of antifungal agents is essential for daily clinical practice.

Performance of polymethyl pentene oxygenators for neonatal extracorporeal membrane oxygenation: a comparison with silicone membrane oxygenators.

OBJECTIVE: To review the performance of polymethyl pentene versus silicone oxygenators in terms of efficiency in priming and oxygenation, oxygenator resistance, requirements for coagulation proteins and consumption of blood products, for neonatal extracorporeal membrane oxygenation (ECMO) patients. STUDY DESIGN: Forty consecutive neonates were selected retrospectively pre- and post-introduction of the new polymethyl pentene (PMP) oxygenators. They formed two equal groups. After calculation of the sample size, data were collected from ELSO registry forms and patient records. Results were analysed using parametric and non-parametric tests. RESULTS: Neonatal PMP (N-PMP) oxygenators were smaller, faster and easier to prime. They were less efficient than silicone oxygenators, especially in carbon dioxide elimination, and, therefore, required higher sweeps. The preservation of coagulation proteins was significantly better, but there was no reduction in the consumption of blood products, despite having less than half the surface area and significantly lower blood path resistance. CONCLUSION: Small PMP oxygenators (Medos Hilite 800 LT) provide adequate gas exchange and offer technical advantages in terms of more efficient priming, reduced haemodynamic resistance and better control and preservation of coagulation proteins than silicone oxygenators.

Hepatotoxicity of antifungal agents.

Antifungal agents have been implicated in numerous cases of hepatotoxicity throughout the past few decades. Hepatotoxic reactions to antifungal agents range from slight, asymptomatic abnormalities in liver function tests to potentially fatal fulminant hepatic failure. Clinically significant hepatic injury resulting from antifungal therapy most commonly manifests as acute hepatocellular, cholestatic or mixed hepatocellular-cholestatic reactions. In general, reactions usually resolve on cessation of therapy, but some antifungal agents may induce chronic liver damage. This review will summarize the hepatotoxicity profiles of the major classes of antifungal agents and will provide recommendations for drug monitoring in order to minimize the risk of hepatotoxicity.

A new era of antifungal therapy.

Invasive fungal infections pose major management problems for clinicians caring for hematopoietic cell transplant patients. Two major fungal genera, Candida and Aspergillus, account for most fungal infections. Rates of systemic Candida infection range from 15% to 25%, mostly in the pre-engraftment period. Prophylaxis by fluconazole has dramatically reduced the frequency of early Candida infections. Caspofungin has recently been shown to offer an excellent alternative to amphotericin B (with less toxicity) or fluconazole (with a broader spectrum) for therapy of systemic Candida infections. Aspergillus infections occur in 15% to 20% of allogeneic hematopoietic cell transplant patients, most frequently in the post-engraftment period; they are associated with a severe diminution of cell-mediated immune responses by graft-versus-host disease and prolonged corticosteroid use. Voriconazole, a recently introduced broad-spectrum azole, has excellent activity against Aspergillus and is generally well tolerated. Voriconazole currently offers the best prospect for success and tolerance as a first-line treatment for aspergillosis. Second-line therapies include lipid formulations of amphotericin B, caspofungin, or intravenous itraconazole. Unfortunately, early initiation of therapy for aspergillosis is frequently not possible because of inaccurate diagnostics. One new diagnostic, the galactomannan assay, has recently been approved, and others are in development; these offer promise for earlier diagnosis without the need for invasive procedures. It is hoped that these new therapies and new diagnostics will usher in a new era of antifungal therapy.

Evaluation of fecal mutagenicity and colorectal cancer risk.

Colorectal cancer is one of the most common internal malignancies in Western society. The cause of this disease appears to be multifactorial and involves genetic as well as environmental aspects. The human colon is continuously exposed to a complex mixture of compounds, which is either of direct dietary origin or the result of digestive, microbial and excretory processes. In order to establish the mutagenic burden of the colorectal mucosa, analysis of specific compounds in feces is usually preferred. Alternatively, the mutagenic potency of fecal extracts has been determined, but the interpretation of these more integrative measurements is hampered by methodological shortcomings. In this review, we focus on exposure of the large bowel to five different classes of fecal mutagens that have previously been related to colorectal cancer risk. These include heterocyclic aromatic amines (HCA) and polycyclic aromatic hydrocarbons (PAH), two exogenous factors that are predominantly ingested as pyrolysis products present in food and (partially) excreted in the feces. Additionally, we discuss N-nitroso-compounds, fecapentaenes and bile acids, all fecal constituents (mainly) of endogenous origin. The mutagenic and carcinogenic potency of the above mentioned compounds as well as their presence in feces, proposed mode of action and potential role in the initiation and promotion of human colorectal cancer are discussed. The combined results from in vitro and in vivo research unequivocally demonstrate that these classes of compounds comprise potent mutagens that induce many different forms of genetic damage and that particularly bile acids and fecapentaenes may also affect the carcinogenic process by epigenetic mechanisms. Large inter-individual differences in levels of exposures have been reported, including those in a range where considerable genetic damage can be expected based on evidence from animal studies. Particularly, however, exposure profiles of PAH and N-nitroso compounds (NOC) have to be more accurately established to come to a risk evaluation. Moreover, lack of human studies and inconsistency between epidemiological data make it impossible to describe colorectal cancer risk as a result of specific exposures in quantitative terms, or even to indicate the relative importance of the mutagens discussed. Particularly, the polymorphisms of genes involved in the metabolism of heterocyclic amines are important determinants of carcinogenic risk. However, the present knowledge of gene-environment interactions with regard to colorectal cancer risk is rather limited. We expect that the introduction of DNA chip technology in colorectal cancer epidemiology will offer new opportunities to identify combinations of exposures and genetic polymorphisms that relate to increased cancer risk. This knowledge will enable us to improve epidemiological study design and statistical power in future research.

Peristomal allergic contact dermatitis due to Gantrez in Stomahesive paste.

We report a case of severe peristomal dermatitis that was refractory to conventional treatments. Patch testing revealed positive allergies to myroxylon perulase (balsam of Peru), propylene glycol, Stomahesive paste, and Gantrez. This is the second reported case of patch-test-positive peristomal allergy to Gantrez.

Rapamycin: personal algorithms for use based on 250 treated renal allograft recipients.

RAPA represents a likely candidate for addition to the maintenance immunosuppressive regimen, for it seems to potentiate markedly the efficacy fo CyA-based therapy. RAPA reduces the incidence of acute rejection episodes; indeed, it may even be useful to disrupt ongoing steroid- and antibody-resistant cellular and humoral acute rejection reactions. Some data in model systems, both in vitro and in vivo, suggest that RAPA may afford prophylaxis against chronic rejection. The enhanced immunosuppression is likely to permit reduction in CyA doses/concentration, thereby mitigating its nephrotoxic effects, and to permit withdrawal of corticosteroids, providing relief from their osteopenic, myopathic, and metabolic effects. As with other potent immunosuppressives, RAPA causes a range of adverse side effects, most importantly myelosuppression and hyperlipidemia. Hypothesis-testing investigations are already underway to elucidate the mechanisms of the adverse effects so as to design strategies to minimize their impact on posttransplant morbidity.

Radioreceptor assay for sirolimus in patients with decreased platelet counts.

OBJECTIVE: Sirolimus (RAPA) is a new immunosuppressive drug currently in Phase III clinical trials in combination with cyclosporine A (CsA). The toxicity profiles for CsA and RAPA are only partially overlapping, with RAPA toxicity consisting primarily of hyperlipidemia and myelodepression but without the nephrotoxicity, neurotoxicity, and hepatotoxicity, which are seen with CsA. Patients in the clinical trial are being monitored using HPLC or LC/MS/MS assays; there is no immunoassay for RAPA reported to date. We have previously reported a radioreceptor assay (RRA) for RAPA, which has an excellent correlation with the HPLC assay (r = 0.997). The RRA has several advantages including excellent precision, sensitivity, rapid turnaround time, and a one-step extraction procedure. We report the evaluation of blood samples from patients who were exhibiting RAPA toxicity and comparison of the RRA results with the HPLC results. METHODS: EDTA whole blood specimens (n = 42) were obtained from six renal transplant recipients taking RAPA and CsA and exhibiting decreased platelet counts. Thirty-two samples from patients without decreased platelet counts were also received. The samples were analyzed with the RRA and the results were compared to those obtained with the HPLC assay. RESULTS: By HPLC, the results ranged from 3.2-72.6 micrograms/L RAPA with 43% of the results > or = 30 micrograms/L. With the RRA, the range was 7.7-83.0 micrograms/L RAPA equivalents, with 60% of the results > or = 30 micrograms/L. The RRA results are distinctly higher than the HPLC results all along the range. The correlation between the two assays was 0.861, with a slope of 0.966 and a Y-intercept of 11.1. CONCLUSION: Since the RRA is consistently higher than HPLC concentration in patients with decreased platelet counts, but correlates well in patients with no signs of toxicity, the RRA may be useful for monitoring patients for toxicity, by giving a better indication of increasing degree of immunosuppression than the HPLC assay.

Kinetics and dynamics of single oral doses of sirolimus in sixteen renal transplant recipients.

Sirolimus is a new immunosuppressive drug that has been evaluated in animal experiments. The current study was conducted on humans with reformulated sirolimus in doses from 3 mg/m2 to 15 mg/m2. Sixteen renal transplant recipients were included in this phase I study to determine the safety, tolerance, and preliminary pharmacokinetics of increasing single doses of orally administered sirolimus. All 16 patients had stable renal graft function after a renal transplant at least 6 months before the study. Basal immunosuppression consisted of cyclosporine and prednisolone (n = 10) or cyclosporine, azathioprine, and prednisolone (n = 6). Four groups (I, 3 mg/m2; II, 5 mg/m2; III, 10 mg/m2; IV, 15 mg/m2) of four patients were assigned randomly to receive sirolimus (n = 3) or placebo (n = 1). Among the 12 patients who received sirolimus, five had mild transient study events such as headache, nausea, mild dizziness, hypoglycemia, epistaxis, and decrease in platelets. No serious adverse events occurred and no nephrotoxic effects could be related to the single dose administration of sirolimus. The only study event that was judged as probably related to sirolimus was the single case of thrombocytopenia. The other events were evaluated as possibly related. Thrombocytopenia occurred at the highest dose level (15 mg/m2 sirolimus). In two of the patients in the placebo group, slight elevations of liver enzymes and serum amylase were seen. Blood and plasma sirolimus concentrations were analyzed by an electrospray-high performance liquid/mass spectrophotometric (ESP-HPLC/MS) method Sirolimus showed an extensive red blood cell distribution with a mean blood/ plasma ratio of 49.1. The elimination half-life ranged from 43.8 to 86.5 hours (mean 56.9 hours). The Cmax and the area under the concentration versus time curves (AUC) correlated reasonably with doses from 3 to 15 mg/m2. The oral dose clearance ranged from 42 to 339 ml/h.kg. No clinically significant differences were seen in the trough concentrations of cyclosporine or the AUCs before and after the administration of sirolimus. Administration of single oral doses of sirolimus from 3 to 15 mg/m2 was safe and well tolerated in stable renal transplant recipients. Thrombocytopenia may be the dose-limiting toxicity. Additional phase II and phase III clinical trials will define the immunosuppressive efficacy of sirolimus.

Clinically significant drug interactions with new immunosuppressive agents.

Tacrolimus (FK506), mycophenolate mofetil, sirolimus (rapamycin), gusperimus, and monoclonal antibody preparations are new immunosuppressive agents, some of which are already approved for clinical use, while others are currently undergoing clinical trials. The present article provides an overview of adverse drug interactions between these immunosuppressants and other drugs which may be used concomitantly. Preliminary data suggest that a pharmacodynamic interaction can occur between tacrolimus and nonsteroidal anti-inflammatory drugs, associated with an increased risk of nephrotoxicity. Erythromycin, clarithromycin, clotrimazole, fluconazole, ketoconazole, and danazol have been shown to increase tacrolimus blood concentrations, while rifampicin (rifampicin) was found to decrease tacrolimus blood concentrations. Evidence from experimental studies suggest that several other drugs also known to affect cytochrome P450 activity may have significant effects on the pharmacokinetics of tacrolimus. On the other hand, tacrolimus itself may inhibit the metabolism of coadministered drugs. This interaction may be attributed to the enhanced renal impairment which has been observed in patients treated with tacrolimus and cyclosporin. The bioavailability of mycophenolic acid, the active metabolite of mycophenolate mofetil, has been reported to be reduced by aluminium/magnesium hydroxide-containing antacids and cholestyramine. Mycophenolic acid, sirolimus and gusperimus may impair bone marrow function and this adverse effect may be enhanced by concomitant administration of other myelosuppressive drugs. There is some evidence that coadministered sirolimus and cyclosporin cause an increase in each other's blood concentrations. An increased risk of central nervous system adverse effects has been described following the combined use of indomethacin and the monoclonal antibody muromonab CD3 (OKT3).