30 research outputs found
Optimización y caracterización de la micro encapsulación de la proteasa hemisfericina refinada
No full textRESUMEN
La hemisfericina refinada (HR) es una preparación de la proteasa cisteínica polimórfica que se obtiene de los frutos de Bromelia hemisphaerica, especie mexicana perteneciente a la familia de las Bromeliáceas. En estudios previos se ha demostrado que la HR compite satisfactoriamente con proteasas comerciales como la papaína en diversas aplicaciones industriales. Interesa, por lo tanto, desarrollar métodos que permitan proteger la actividad enzimática durante el almacenamiento y conservar su estabilidad operacional. Las conocidas sensibilidad a la temperatura de las enzimas y susceptibilidad a diversos factores desnaturalizantes del medio pueden reducirse mediante la microencapsulación de la materia enzimática empleando el secado por aspersión.
En el presente trabajo se establecieron las condiciones para microencapsular HR con goma arábiga mediante secado por aspersión. El estudio del proceso de encapsulación incluyó el análisis de diferentes concentraciones de goma arábiga (GA) (7-22%) y de temperaturas (T) de entrada en el secado entre 105-
135°C, empleando un secador de laboratorio (Mini Spray Dryer, modelo B-290, Büchi). Se utilizó la metodología de superficies de respuesta para encontrar las mejores condiciones del proceso que permitieran conservar una actividad proteolítica máxima, empleándose para ello un diseño central compuesto (DCC) con cinco repeticiones en el punto central en 13 corridas. Las variables de r espuesta fueron: el rendimiento de microencapsulación, la actividad proteolítica y l a concentración de proteína. Estas dos últimas fueron evaluadas periódicamente durante dos meses de almacenamiento. Las microcápsulas fueron evaluadas mediante electroforesis en gel de poliacrilamida y microscopía electrónica de barrido.
Las preparaciones que presentaron mejor actividad proteolítica en el período de almacenamiento ensayado fueron: las obtenidas con 7.9% de GA y T de 120 °C (corrida 13), las cuales no solamente mantuvieron su actividad sino que la mejoraron en un 14.8% con respecto a la inicial de la muestra; así como, las cápsulas con 10% de GA y T de 130 °C (corrida 7) que presentaron una actividad 14.2% mayor que la inicial (tiempo cero). La muestra que presentó la mejor estabilidad fue la obtenida en el punto central con condiciones de 15% de CGA y 120°C de T, no obstante su actividad enzimática (711
UT/mg de proteína) fue menor que la obtenida bajo las condiciones de las corridas 7 y 13 (932 y 890
UT/mg de proteína). Se identificó en las preparaciones microencapsuladas las bandas electr oforéticas características que corresponden a HR (24 kDa).
ABSTRACT
Refined hemisphaericin (HR) is a preparation from the cysteine polymorphic protease obtained from the fruits of Bromelia hemisphaerica, a mexican plant which belongs to the Bromeliaceae family. In previous studies on industrial applications it has been reported that HR competes satisfactorily with commercial proteases like papain. Therefore it becomes of interest to develop methods focused on the protection of enzyme activity during stora ge and the preservation of operational stability. Enzyme susceptibility to temperature and other denaturing factors in the environment is well known, this sensitivity may be diminished by microencapsulation of the enzyme material by spray drying.
In the present work the conditions were settled for the microencapsulation of HR with arabic gum by spray drying. The study of HR encapsulation process included the analysis of different arabic gum (AG) concentrations (7 -22%) at several feed temperatures (T) between 105 and 135 °C, in a laboratory Mini Spray Dryer (model B-290, Büchi). In order to find the best conditions for this process to keep a maximal proteolytic activity, response surface methodology was used, with a composite central design (CCD) with five repetitions in the central point with 13 runs. The following response variables were used: microencapsulation yield, proteolytic activity and protein concentration. The last two variables were evaluated periodically within two months of storage. The microcapsules were assayed by polyacrylamide gel electrophoresis (PAGE) and scanni ng electronic microscopy (SEM).
The better stability at the assayed time of storage was found for the proteolytic preparations obtained with AG 7.9% at 120ºC ( run 13), which improved the initial activity in 14.8%; just like the capsules prepared with AG 10% at 130ºC ( run 7) which showed a 14.2% greater activity than the initial sample (zero time). The sample with more stability was that obtained at the central point with AG
15% and 120ºC, nevertheless, it presented lower activity (711 UT/mg protein) than those obtained under the assayed conditions in runs 7 and 13 (932 and 890 UT/mg protein). The microencapsulated preparations rendered the characteristic bands of HR (24 kDa) by PAGE
Bone aspects after implant site preparation using Drill vs Uisp with different irrigation flow. An in-vitro study with scanni electron microscopy
No full textRationale for Treatment and Study Design of TAILOR: A Randomized Phase III Trial of Second-line Erlotinib Versus Docetaxel in the Treatment of Patients Affected by Advanced Non-Small-Cell Lung Cancer With the Absence of Epidermal Growth Factor Receptor Mutations
No full textWe present the rationale and study design of the Tarceva Italian Lung Optimization trial phase III, multicenter, open-label, randomized trial on efficacy of second-line therapies in different subgroups of non small-cell lung cancer (NSCLC) patients identified using molecular and clinical evaluations. To date, we can assume that advanced NSCLC epidermal growth factor receptor (EGFR) mutated patients benefit from EGFR tyrosine kinase inhibitors, such as gefitinib and erlotinib, whereas their role in the treatment of patients who do not have EGFR mutations is controversial. The aim of this study is to assess whether it is possible to optimize second-line treatment in NSCLC patients with absence of EGFR mutations. Moreover, the predictive value of the K-ras mutation, EGFR protein expression, and EGFR gene copy number, as well as a smoking habit and histotype for determining a different effect of erlotinib, compared with chemotherapy will be assessed in patients who do not have EGFR mutations. The primary endpoint, is overall survival; the secondary endpoints are progression-free survival, response rate, quality of life, and toxicity. We have planned to collect blood samples to identify different prognosis-related polymorphisms and to assess their sensitivity and specificity in the detection of EGFR and K-ras mutations with respect to histologic samples
Paclitaxel and epirubicin followed by cyclophosphamide, methotrexate and 5-fluorouracil for patients with stage IIIC breast cancer with ten or more involved axillary lymph nodes
No full textObjective:
The aim of this study was to evaluate the feasibility of a combination of epirubicin and paclitaxel followed by intravenous (iv) cyclophosphamide, methotrexate, and 5-fluorouracile (CMF) as adjuvant treatment of breast cancer patients with 10 or more metastatic axillary lymph nodes.
Methods:
Forty-four patients entered this multicenter study and received 4 cycles of epirubicin (E 120 mg/m2 day 1, q3 weeks) and paclitaxel (T 135 mg/m2 day 1, q3 weeks), followed by 4 cycles of iv CMF (days 1 and 8, q4 weeks). Patients with positive hormonal receptors received sequentially tamoxifen associated with LH-RH analogue if premenopausal. The endpoints were the evaluation of the feasibility of this schedule and disease free survival (DFS).
Results:
Median age of patients was 55; median number of positive axillary nodes was 14 (range, 10–47). Hormonal receptor status was positive in 57% of patients. The combination of epirubicin and paclitaxel was well tolerated; NCI grade 3/4 events were: leucopenia in 27% of patients, neutropenic fever in 5 patients, anemia in 7%, thrombocytopenia in 7%, nausea in 18%, vomiting in 14%, and neurotoxicity in 4%. CMF regimen caused a few cases of grade 3/4 hematologic toxicity. No cardiac toxicity was recorded. With a median follow-up of 59 months, 18 (41%) patients relapsed. Sites of relapse were mainly bone, skin/soft tissues, liver, and lung. Median DFS was 78 months, with a 5-year rate of 60%.
Conclusions:
The combination of paclitaxel at low dose and epirubicin followed by CMF is a feasible regimen, which seems to be effective in high-risk node positive breast cancer patients and requires further investigations
Calcification of Humeral Metastasis of Renal Adenocarcinoma 8 Months after Medroxyprogesterone Acetate Therapy
No full textCyclophosphamide, Methotrexate, 5-Fluorouracil (CMF) in Advanced Gastrointestinal Cancer
No full text The effectiveness of the cyclophosphamide + methotrexate + 5-fluorouracil schedule (CMF) in 28 patients with advanced gastrointestinal cancer has been studied. No complete remission was obtained; partial remission and objective improvement constituted 56%. The median response period is calculated at a minimum of 12 months, without significant differences between the group of patients previously subjected to palliative canalization surgery and the group of patients not subjected to this operation. The overall median survival time is 10.8 months. On the basis of the data given, the authors conclude by stressing that the CMF combination should be studied more fully in relation to its use in gastrointestinal forms of cancer. </jats:p
Combination of Mitomycin C + Etoposide in Advanced Gastric Carcinoma
No full text In June 1981 the authors activated a trial to evaluate the therapeutic effectiveness of the combination mitomycin C (MMC) + etoposide (VP 16) in previously untreated gastric carcinoma with measurable neoplastic lesions. Drugs were administered according to the following schedule: MMC, 12 mg/m2 i.v. day 1, + VP 16, 150-200 mg/m2 orally days 2, 3, 4, 22, 23, 24 every 6 weeks. The response rate (CR+PR) was 16.7 %, which is not higher than that obtained when MMC and VP 16 are used as single agents. Overall median survival (8 months) was similar to that reported in the recent literature with combination chemotherapy. </jats:p
III. PRAYERS OF FEMALE PROTAGONISTS IN GIUSEPPE VERDI’S OPERAS. LUCREZIA’S CAVATINA – “TU AL CUI SGUARDO ONNIPOSSENTE” (ACT I, SCENE 2) FROM VERDI’S „I DUE FOSCARI”
No full textWith this analysis the author continues with the presentation of the prayers of female protagonists[1] from Giuseppe Verdi’s operas, a lesser-known topic within the vast bibliography dedicated to the oeuvre of the great Italian Maestro. After presenting prayers from Nabucco and I Lombardi alla prima crociata, the author now addresses a less conspicuous prayer "hidden" in the pages of I due Foscari: Lucrezia Contarini’s Cavatina (with its bel canto traits and featuring a female choir). Further analyses published in this series will shed light upon well-known examples of preghiere – such as famous prayers of Leonora from La Forza del Destino –, as well as other arias which bear further bel canto influences (preghiere from Giovanna d\u27Arco and Stiffelio), but also illustrating how the musical language of female prayers has transformed in Verdi\u27s more mature operatic works, such as Aida and Otello.
[1] The aforementioned analyses focus only on prayers uttered to divinities (both in Christian and pagan contexts), saints or the Virgin Mary, but exclude prayers addressed to the dead (e.g. Lina’s second act prayer from Stiffelio – Ah, dagli scanni eterei)
III. PRAYERS OF FEMALE PROTAGONISTS IN GIUSEPPE VERDI’S OPERAS. LUCREZIA’S CAVATINA – “TU AL CUI SGUARDO ONNIPOSSENTE” (ACT I, SCENE 2) FROM VERDI’S „I DUE FOSCARI”
No full textWith this analysis the author continues with the presentation of the prayers of female protagonists[1] from Giuseppe Verdi’s operas, a lesser-known topic within the vast bibliography dedicated to the oeuvre of the great Italian Maestro. After presenting prayers from Nabucco and I Lombardi alla prima crociata, the author now addresses a less conspicuous prayer "hidden" in the pages of I due Foscari: Lucrezia Contarini’s Cavatina (with its bel canto traits and featuring a female choir). Further analyses published in this series will shed light upon well-known examples of preghiere – such as famous prayers of Leonora from La Forza del Destino –, as well as other arias which bear further bel canto influences (preghiere from Giovanna d'Arco and Stiffelio), but also illustrating how the musical language of female prayers has transformed in Verdi's more mature operatic works, such as Aida and Otello.
[1] The aforementioned analyses focus only on prayers uttered to divinities (both in Christian and pagan contexts), saints or the Virgin Mary, but exclude prayers addressed to the dead (e.g. Lina’s second act prayer from Stiffelio – Ah, dagli scanni eterei)
