Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
Add more filters










Publication year range
1.
Brain Sci ; 13(6)2023 May 27.
Article in English | MEDLINE | ID: mdl-37371349

ABSTRACT

Glioblastoma is the most aggressive and lethal brain tumor in adults, presenting diffuse brain infiltration, necrosis, and drug resistance. Although new drugs have been approved for recurrent patients, the median survival rate is two years; therefore, new alternatives to treat these patients are required. Previous studies have reported the anticancer activity of albendazole, its active metabolite albendazole sulfoxide, and melatonin; therefore, the present study was performed to evaluate if the combination of melatonin with albendazole or with albendazole sulfoxide induces an additive or synergistic cytotoxic effect on C6 and RG2 rat glioma cells, as well as on U87 human glioblastoma cells. Drug interaction was determined by the Chou-Talalay method. We evaluated the mechanism of cell death by flow cytometry, immunofluorescence, and crystal violet staining. The cytotoxicity of the combinations was mainly synergistic. The combined treatments induced significantly more apoptotic and autophagic cell death on the glioma cell lines. Additionally, albendazole and albendazole sulfoxide inhibited proliferation independently of melatonin. Our data justify continuing with the evaluation of this proposal since the combinations could be a potential strategy to aid in the treatment of glioblastoma.

2.
RSC Adv ; 12(36): 23153-23161, 2022 Aug 16.
Article in English | MEDLINE | ID: mdl-36090413

ABSTRACT

The improvement of permeation of drugs across parasites' membranes to promote their diffusion component represents a challenge to achieve better therapeutic effects, including the avoidance of drug resistance. In the context of medicinal chemistry, suitable structural modifications can be made, either on a drug or a nanocarrier, to trigger different mechanisms that promote the influx across membranes. This study aimed to demonstrate the potential of a set of dendritic derivatives of ß-cyclodextrin (m2G, h2G, and m3G) as nanocarriers, based on their physicochemical and biological behavior in terms of (i) stability, monitored by 1H NMR at pH 7 for seven days, (ii) ability to complex, and subsequently release around 50-80% of the cargo molecule (albendazole) in a biphasic medium and (iii) the absence of in vitro cysticidal effect in cysticercus cultures. The albendazole/nanocarrier inclusion complexes (ICs) were proved in the T. crassiceps model. According to the EC50 values related to the cysticidal activity of albendazole, either free or complexed, the potency of this drug in the ICs experienced a significant increase, which may be attributed to the enhancement of its solubility but also to a better permeation mediated by the amphiphilic dendritic moieties, which ultimately positively impacts the diffusion of this drug through the tegument of the cysticerci. Additional considerations akin to synthetic ease of the dendritic nanocarriers, and production cost, along with the obtained outcomes, allowed us to place m2G followed by m3G as the best options to be considered for further in vivo assays.

3.
Plants (Basel) ; 10(5)2021 Apr 30.
Article in English | MEDLINE | ID: mdl-33946183

ABSTRACT

Greenhouse cultivation of table grapes is a challenge due to difficulties imposed by their perennial habit and chilling requirements. Despite difficulties, greenhouse cultivation allows ripening long before that in the open field. Nonetheless, for harvesting "Flame Seedless" in the most profitable periods, a cultural practices timetable has to be established. In this context, an estimation of development rate as a function of temperature becomes essential. This work puts forward a procedure to determine "Flame Seedless" threshold temperatures and heat requirements from bud break to ripening. "Flame Seedless" required an average of 1633 growing degree days (GDD) in the open field with a base temperature of 5 °C and an upper threshold temperature of 30 °C. Strikingly, only 1542 GDD were required within the greenhouse. This procedure forecast "Flame Seedless" ripening with an accuracy of three and six days in the open field and greenhouse, improving predictions based on the average number of days between bud break and ripening. The procedure to predict oncoming harvest date was found satisfactory, just four days earlier than the real date. If we used the typical meteorological year instead of the average year, then the prediction was greatly improved since harvest was forecast just one day before its occurrence.

4.
Sensors (Basel) ; 21(1)2020 Dec 30.
Article in English | MEDLINE | ID: mdl-33396728

ABSTRACT

Water and nutrient requirements of horticultural crops are influenced by different factors such as: Type of crop, stage of development and production system. Although greenhouse horticultural crops are more efficient in the use of water and fertilizers compared to other production systems, it is necessary increase efficiency for which individualized fertigation strategies must be designed for each greenhouse. The automation of fertigation based on the level of soil moisture allows optimization of management. The objective of this work was to determine the influence of the activation command of fertigation with electrotensiometers and the characteristics of the greenhouse on the productivity of the crop and the efficiency of use of water and nutrients in a sweet pepper crop. The trial was developed in two greenhouses. Four treatments were studied, combination of who two-factor: Soil matric potential (SMP) (SMP-10: Automatic activation of irrigation to -10 kPa and SMP-20: Automatic activation of irrigation to -20 kPa) and greenhouse characteristics (G1 and G2). The nutritive solution applied was the same in all treatments. The yield and volume of water and nutrients applied were determined, calculating the productivity of the water (WP), as well as productivity the nutrients. The fertigation activation threshold of -10 kPa presented the best results, increasing the yield and conserving WP and nutrient productivity with respect to -20 kPa in both greenhouses. The automation of irrigation with electrotensiometers allowed the application of different volume of fertigation demanded by the crop in each greenhouse, equalizing the WP and nutrient productivity without producing drainage. The pepper crop in the greenhouse G1 presented greater vegetative development, higher yield and demanded a greater volume of fertigation than G2 regardless of the activation threshold. This was due to the fact that the soil matric potential after irrigation in greenhouse G1 was closer to zero, being able to conclude that not only the soil matric potential threshold of irrigation activation has an influence on crop, but also the potential registered after irrigation. Soil matric potentials closer to zero are more productive.

5.
Exp Parasitol ; 208: 107801, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31730781

ABSTRACT

Taenia solium is a parasite whose larvae (cysticerci) can locate in the central nervous system of humans and cause neurocysticercosis (NC). The introduction of cysticidal drugs such as albendazole (ABZ) for the treatment of NC has significantly improved its prognosis. However, treatment is not always effective, and the high levels of corticosteroids used to prevent inflammatory complications in this disease could be, partly, the cause of this observation. In this context, this study investigated, using the experimental mouse model of intraperitoneal infection with Taenia crassiceps, the influence of corticosteroid administration on the therapeutic efficacy of ABZ. We evaluated and compared the effects of ABZ, dexamethasone (DXM) and their combination (ABZ + DXM) on cyst viability, both in vitro and in vivo. Serum levels of IL-4, IFN-gamma, IL-6 and IL-10 were evaluated in the in vivo study. Results showed that the treatment with ABZ, in vitro and in vivo, was associated with a high number of parasites deaths. Concomitant treatment with DXM did not alter ABZ in vitro cysticidal activity but reduced its effectiveness significantly in the in vivo experimental model. Cytokine serum levels did not change significantly in treated mice compared to the controls. The results of this study are relevant as they indicate a negative effect of corticosteroids on the efficacy of cysticidal therapy. In human neurocysticercosis, control of inflammation is of great importance to most patients in order to avoid complications. Corticosteroids are generally used for this purpose and the results of this study demonstrate the need to find other therapeutic strategies. Further studies are needed to better understand the mechanisms involved.


Subject(s)
Albendazole/pharmacology , Anthelmintics/pharmacology , Anti-Inflammatory Agents/pharmacology , Cysticercosis/drug therapy , Dexamethasone/pharmacology , Taenia/drug effects , Albendazole/therapeutic use , Animals , Anthelmintics/therapeutic use , Anti-Inflammatory Agents/therapeutic use , Dexamethasone/therapeutic use , Drug Interactions , Enzyme-Linked Immunosorbent Assay , Female , Interferon-gamma/blood , Interleukin-10/blood , Interleukin-4/blood , Interleukin-6/blood , Mice , Mice, Inbred BALB C
6.
Chem Pharm Bull (Tokyo) ; 67(12): 1293-1300, 2019.
Article in English | MEDLINE | ID: mdl-31787656

ABSTRACT

Based on our previous research on cysticidal drugs, we report the synthesis and evaluation of three new benzimidazole derivatives. In these compounds, the amido group was used as a bioisosteric replacement of the ester group. The molecular docking on ß-tubulin revealed that the derivatives interacted through hydrogen bonding with N165, E198 and V236. All compounds showed in vitro activity against Taenia crassiceps cysts. Among them, benzimidazole 3 was found to be the most potent of the series (EC50 0.86 µM). This compound also exhibited the highest probability of binding and the lowest binding free energy score and was therefore selected for in vivo evaluation. Results indicated that the efficacy of compound 3 was comparable to that of the reference drug, albendazole (50.39 vs. 47.16% parasite reduction). Animals treated with compound 3 seemed to tolerate this benzimidazole well, with no changes in behavior, or food and water consumption. These findings are consistent with the in silico prediction results, which indicated low toxicity risks. The pharmacokinetic study showed that the half-life and mean residence time (6.06 and 11.9 h, respectively) were long after oral administration. Together, these results indicate that this new benzimidazole derivative represents a promising structure with cysticidal activity.


Subject(s)
Amebicides/pharmacology , Benzimidazoles/pharmacology , Cysticercosis/drug therapy , Molecular Docking Simulation , Taenia/drug effects , Amebicides/chemical synthesis , Amebicides/chemistry , Animals , Benzimidazoles/chemical synthesis , Benzimidazoles/chemistry , Dose-Response Relationship, Drug , Female , Mice , Mice, Inbred BALB C , Molecular Structure , Structure-Activity Relationship
7.
Nutr. hosp ; 35(2): 359-367, mar.-abr. 2018. tab, graf
Article in English | IBECS | ID: ibc-172748

ABSTRACT

Background: overweight and obesity have been increasing, and university students are an important target for prevention programs. Previous studies have reported differences in the diagnosis between different anthropometric methods, so some students can be misclassified depending on the method used. Objective: to evaluate the efficacy of different anthropometric methods to detect those university students in a probable status of overweight, including a comparison with a new proposed method, the normalized weight-adjusted index (NWAI). Methods: different anthropometric methods (waist circumference, waist-hip ratio, waist-height ratio, body mass index, conicity index, bioimpedance and Brozek, Siri and Heath-Carter equations) were calculated for 505 university students. By k-means cluster analysis, students with higher values according to variables involved in overweight were identified. Parameters of accuracy were calculated by operating characteristic curves. Results: NWAI showed significant correlations with the most used methods. Prevalence of students with body fat excess varied from 5.9% to 48.4% for women and from 8.5% to 49.0% for men depending of the method employed, being demonstrated a great variability between the different methodologies. Body mass index for women and waist circumference for men resulted to be the most accurate methods to detect a probable situation of excess of body fat or cardiovascular risk associated. NWAI resulted also a good alternative for overweight classification. Conclusions: differences between anthropometric methods for overweight and cardiovascular disease risk classification were confirmed. Classical cut-off point may misdiagnose overweight or health risk in Spanish university students depending of the method employed


Introducción: el sobrepeso y la obesidad han ido en aumento, y los estudiantes universitarios son un objetivo importante para los programas de prevención. Estudios previos demuestran diferencias en el diagnóstico según el método antropométrico utilizado. Objetivo: evaluar la eficacia de diferentes métodos antropométricos para detectar a los estudiantes universitarios en un probable estado de sobrepeso y comparar con un nuevo método, el índice normalizado ajustado al peso (INAP). Metodología: se utilizaron diferentes métodos antropométricos (circunferencia de cintura, cociente cintura cadera, relación cintura-altura, índice de masa corporal, índice de conicidad, bioimpedancia y ecuaciones de Brozek, Siri y Heath-Carter) para 505 estudiantes universitarios. Se identificaron los estudiantes con valores más altos de acuerdo a las variables involucradas en el sobrepeso y se calculó la precisión de los distintos métodos antropométricos. Resultados: el INAP mostró correlaciones significativas con los métodos más utilizados. La prevalencia de estudiantes con exceso de grasa corporal varió para las mujeres del 29,4% al 78,1% y para los varones del 12,0% al 54,0% dependiendo del método empleado. El índice de masa corporal para las mujeres y la circunferencia de cintura para los hombres fueron los métodos más precisos para detectar un probable exceso de grasa corporal o riesgo cardiovascular asociado. El INAP resultó una buena alternativa para la clasificación de sobrepeso. Conclusiones: se confirmaron las diferencias entre los métodos antropométricos para el sobrepeso y la estimación de riesgo cardiovascular. Los puntos de corte clásicos pueden diagnosticar erróneamente sobrepeso o riesgo para la salud en estudiantes universitarios españoles dependiendo del método empleado


Subject(s)
Humans , Overweight/diagnosis , Anthropometry/instrumentation , Cardiovascular Diseases/prevention & control , Body Weight , Students/statistics & numerical data , Obesity/prevention & control , Reproducibility of Results , Risk Factors , Reproducibility of Results
8.
Saudi Pharm J ; 25(3): 413-418, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28344497

ABSTRACT

Background: Although albendazole is the drug-of-choice for the treatment of neurocysticercosis, its efficacy is limited due to its low bioavailability. An alternative for optimizing pharmacological treatment is through drug combinations. In vitro studies have shown that nitazoxanide and tizoxanide (the active metabolite of nitazoxanide) exhibit cysticidal activity and that the combination of tizoxanide with albendazole sulfoxide (the active metabolite of albendazole) produced an additive effect. Objectives: (1) To assess the concentration profile of tizoxanide in plasma and in cerebrospinal fluid; and (2) to evaluate the influence of nitazoxanide on the pharmacokinetics of albendazole in plasma and in cerebrospinal fluid. Methods: Two different studies were conducted. In study 1, 10 male Sprague-Dawley rats received a single oral dose of 7.5 mg/kg of nitazoxanide and serial blood and cerebrospinal fluid samples were collected over a period of 4 h. In study 2, 38 healthy male Sprague-Dawley rats were randomly divided into two groups: one of these received a single dose of albendazole (15 mg/kg) and, in the other group, albendazole (15 mg/kg) was co-administered with nitazoxanide (7.5 mg/kg). Plasma and cerebrospinal fluid samples were collected from 0 to 16 h after administration. Albendazole sulfoxide and tizoxanide levels were assayed by using HPLC or LC/MS techniques. Results: In study 1, tizoxanide reached a maximum plasma concentration of 244.42 ± 31.98 ng/mL at 0.25 h; however, in cerebrospinal fluid, this could be detected only at 0.5 h, and levels were below the quantification limit (10 ng/mL). These data indicate low permeation of tizoxanide into the blood brain barrier. In study 2, Cmax, the area under the curve, and the mean residence time of albendazole sulfoxide in plasma and cerebrospinal fluid were not affected by co-administration with nitazoxanide. Conclusion: The results of the present study indicate that in rats at the applied doses, tizoxanide does not permeate into the cerebrospinal fluid. Furthermore, nitazoxanide does not appear to alter significantly the pharmacokinetics of albendazole in plasma or in cerebrospinal fluid.

9.
Acta Trop ; 170: 1-7, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28216368

ABSTRACT

Currently, neurocysticercosis treatment involves two drugs: albendazole and praziquantel; however, their efficacy is suboptimal and new cysticidal drugs are needed. The present paper reports the cysticidal activity of extracts of the bark from Prunus serotina against Taenia crassiceps cysts and the isolation and identification of the main components of the most active extract. Results showed that all extracts displayed in vitro cysticidal activity (EC50=17.9-88.5µg/mL), being the methanolic the most active and selective. Also, methanolic extract exhibited in vivo efficacy at 300mg/kg which was similar to that obtained with albendazole. Bio-guided fractionation of methanolic extract led the isolation of 2,3-dihydro-5,7-dihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one (naringenin, NGN), 3,4,5-trimethoxybenzoic acid and 1,3,5-trimethoxybenzene. NGN exhibited in vitro activity, in a time-concentration-dependent manner (EC50=89.3µM]. Furthermore, NGN at a dose of 376.1µmol/kg displayed similar in vivo efficacy than those obtained with albendazole at 188.4µmol/kg. NGN also caused a high level of damage in all parasite tissue in a similar manner than that observed with the methanolic extract. This study represents the first report of the cysticidal properties of the bark of P. serotina. NGN was identified as the main active compound of this specie and other studies are required to explore the potential of this flavanone as cysticidal agent.


Subject(s)
Anthelmintics/pharmacology , Cysticercosis/drug therapy , Flavanones/pharmacology , Plant Extracts/pharmacology , Prunus avium , Taenia/drug effects , Albendazole/pharmacology , Animals , Female , Mice , Mice, Inbred BALB C
10.
Exp Parasitol ; 156: 79-86, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26072200

ABSTRACT

In the search of new alternatives for neurocysticercosis treatment, the cysticidal activity of organic extracts of Teloxys graveolens was evaluated. The in vitro activity of hexane, ethyl acetate and methanol extracts against Taenia crassiceps cysts was tested and the selectivity index relative to human fibroblasts was determined. Subsequently, the in vivo efficacy of the methanolic extract at doses of 200 and 500 mg/kg in the murine cysticercosis model was evaluated. The ultrastructural effects in vitro and in vivo of the methanolic extract were also investigated using scanning electron microscopy. Additionally, a bioassay-guided fractionation for the isolation of the cysticidal components was performed. Our in vitro findings revealed that all extracts exhibited good cysticidal activity with EC50 values from 44.8 to 67.1 µg/mL. Although the ethyl acetate and methanolic extracts displayed low cytotoxicity, the methanolic extract was the most selective. The methanolic extract also showed in vivo efficacy which was similar to that obtained with ABZ. Significant alterations were found on the germinal layer of the cysts, with a high accumulation of granules of glycogen and vacuoles. The bioguided fractionation of methanolic extract led to the isolation of three flavonoids: chrysin, pinocembrin and pinostrobin; among them, pinocembrin was the compound that displayed cysticidal activity. This is the first study which reveals that T. graveolens could be a potential source for cysticidal and non-toxic compounds.


Subject(s)
Amaranthaceae/chemistry , Cysticercosis/drug therapy , Cysticercus/drug effects , Plant Extracts/pharmacology , Animals , Biological Assay , Cysticercus/ultrastructure , Female , Fibroblasts/drug effects , Flavanones/chemistry , Flavanones/isolation & purification , Flavanones/pharmacology , Flavonoids/chemistry , Flavonoids/isolation & purification , Flavonoids/pharmacology , Gingiva/cytology , Humans , Mice , Mice, Inbred BALB C , Microscopy, Electron, Transmission , Plant Components, Aerial/chemistry , Plant Extracts/chemistry , Plant Extracts/therapeutic use , Plant Extracts/toxicity
11.
Exp Parasitol ; 149: 1-6, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25500213

ABSTRACT

In the search of new alternatives for neurocysticercosis treatment, Taenia crassiceps ORF strain cysticerci have been used instead of T. solium for in vitro studies. Up to date, the main criteria for the use of the murine cysticercosis model for drug efficacy evaluation have not been assessed. The aim of the present study was to evaluate the influence of two of the main variables related to the in vivo efficacy: the length of drug treatment and the starting time of treatment after experimental infection, using albendazole (ABZ) and praziquantel (PZQ) as test drugs. Additionally, the relationship between the number of cysts and the parasite weight was assessed. For the study, female BALB/c mice were experimentally infected with T. crassiceps cysts. Three different post-infection periods (10, 20 and 30 days) and three different lengths of treatment with ABZ or PZQ (10, 20 and 30 days) were selected. The efficacy of each treatment was evaluated by comparison with a control group. Our results show that for in vivo efficacy studies, the best time to start the drug treatment is 10 days post-infection and that a minimum of 20 days of treatment is required when ABZ or PZQ are used as positive control. Moreover, in this model the parasite weight can be used as a rapid tool to measure the in vivo drug activity.


Subject(s)
Albendazole/therapeutic use , Anthelmintics/therapeutic use , Cysticercosis/drug therapy , Praziquantel/therapeutic use , Albendazole/administration & dosage , Animals , Anthelmintics/administration & dosage , Cysticercosis/parasitology , Cysticercus/drug effects , Disease Models, Animal , Drug Administration Schedule , Drug Evaluation, Preclinical , Female , Mice , Mice, Inbred BALB C , Praziquantel/administration & dosage , Time Factors
12.
Cent Nerv Syst Agents Med Chem ; 11(3): 223-7, 2011 Sep 01.
Article in English | MEDLINE | ID: mdl-21919869

ABSTRACT

OBJECTIVE: Cefepime neurotoxicity usually occurs in patients with renal impairment. The aim of this study was to evaluate the neurotoxicity of cefepime administered by continuous intravenous infusion during treatment of nosocomial infections in neurological patients with normal renal function. METHODS: This was an open pilot study of neurological patients with infections caused by cefepime sensitive bacteria. Patients had baseline neurological assessment and electroencephalogram (EEG). Cefepime plasma concentrations were determined 48 hours after infusion was initiated and at end of treatment (EOT). RESULTS: Eleven patients were included. These were diagnosed with a brain tumor (9), cerebrovascular disease (1) and polyneuropathy (1). Infections were surgical site infection in 5, clinically defined nosocomial pneumonia in 4, and bacterial meningitis associated to postoperative CSF fistula in 2. Gram-negative organisms were isolated in 10 patients. Cefepime dose was 2 g/day in 9 patients and 4 g/day in 2. Mean cefepime plasma concentration at 48h was 13.6 ± 2.0 µg/mL (range 4.6 to 24.5 µg/mL), at EOT was 11.9 ± 1.8 µg/mL (range 3.0 to18.9 µg/mL ). EEG interpreted by two experts showed at baseline alpha background rhythm in 5 and theta-alpha rhythm in 6 patients. On EEG at EOT background rhythm was alpha in 4 and theta-alpha in 7, one patient presented isolated sharp and slow wave activity. No mental status changes or seizures occurred and all infections resolved. CONCLUSION: Significant EEG change was observed in 1of 11 patients. A preserved mental status may correlate with cefepime safety in neurological patients with normal renal function during cefepime treatment.


Subject(s)
Anti-Bacterial Agents/adverse effects , Anti-Bacterial Agents/therapeutic use , Cephalosporins/adverse effects , Cephalosporins/therapeutic use , Cross Infection/drug therapy , Electroencephalography/drug effects , Mental Disorders/physiopathology , Adult , Anti-Bacterial Agents/administration & dosage , Cefepime , Cephalosporins/administration & dosage , Female , Humans , Infusions, Intravenous , Male , Microbial Sensitivity Tests , Middle Aged , Pilot Projects , Young Adult
13.
Acta Trop ; 113(1): 56-60, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19769931

ABSTRACT

The effect of two water-soluble polymers: pectin and polyvinylpyrrolidone in combination with beta-cyclodextrin, on the dissolution, bioavailability and cysticidal efficacy of albendazole was evaluated using a commercial suspension as reference product. The dissolution of the albendazole-beta-cyclodextrin-pectin formulation was slow and incomplete (44.7%). No statistical differences in C(max) and AUC were found between this formulation and the reference. Also its cysticidal efficacy (33%) was similar to the reference (38%). The albendazole-beta-cyclodextrin-polyvinylpyrrolidone formulation exhibited the highest dissolution rate (78.5%) and its bioavailability was also significantly increased (2.3-fold). In addition, the cysticidal activity of this formulation (83%) was greater than a commercial suspension. Our results suggest that the ternary system of albendazole-beta-cyclodextrin-polyvinylpyrrolidone could be a potential alternative for the treatment of systemic helmintic diseases and it is worth to continue its preclinical evaluation.


Subject(s)
Albendazole/pharmacology , Anticestodal Agents/pharmacology , Pectins/pharmacology , Taenia/drug effects , beta-Cyclodextrins/pharmacology , Albendazole/chemistry , Albendazole/pharmacokinetics , Animals , Anticestodal Agents/chemistry , Anticestodal Agents/pharmacokinetics , Male , Mice , Mice, Inbred BALB C , Pectins/chemistry , Pectins/pharmacokinetics , Rats , Rats, Wistar , beta-Cyclodextrins/chemistry , beta-Cyclodextrins/pharmacokinetics
14.
Eur J Med Chem ; 44(4): 1794-800, 2009 Apr.
Article in English | MEDLINE | ID: mdl-18582991

ABSTRACT

Despite albendazole being the drug of choice in neurocysticercosis treatment, its low solubility limits its bioavailability; therefore, more research is required in order to find new molecules with cestocidal activity and adequate aqueous solubility. A set of 13 benzimidazole derivatives were synthesized and their in vitro activities were evaluated against Taenia crassiceps cysts, using albendazole sulfoxide as reference molecule, showing that two of them exhibited good activity. Molecular modelling revealed that the cysticidal efficacy depends on the presence on the molecule of an H in the 1-position, a planar carbamate group at 2-position, and if the substituent in 5-position is voluminous, it should be orthogonal to the benzimidazole ring.


Subject(s)
Anthelmintics/chemistry , Anthelmintics/pharmacology , Benzimidazoles/chemistry , Benzimidazoles/pharmacology , Drug Design , Taenia/drug effects , Albendazole/analogs & derivatives , Albendazole/pharmacology , Animals , Anthelmintics/chemical synthesis , Benzimidazoles/chemical synthesis , Models, Molecular , Reference Standards
15.
Int J Biometeorol ; 51(5): 449-55, 2007 May.
Article in English | MEDLINE | ID: mdl-17211640

ABSTRACT

Plant phenology is in great measure driven by air temperature. To forecast harvest time for 'Algerie' loquat accurately, the growing degree days (GDD) needed from bloom to ripening were determined using data from nine seasons. The methods proposed by Zalom et al. (Zalom FG, Goodell PB, Wilson LT, Barnett WW, Bentley W, Degree-days: the calculation and use of heat units in pest management, leaflet no 21373, Division Agriculture and Natural Resources, University of California 10 pp, 1983) were compared as regards their ability to estimate heat summation based on hourly records. All the methods gave remarkably similar results for our cultivation area, although the double-sine method showed higher performance when temperatures were low. A base temperature of 3 degrees C is proposed for 'Algerie' loquat because it provides a coefficient of variation in GDD among seasons of below 5%, and because of its compatibility with loquat growth. Based on these determinations, 'Algerie' loquat requires 1,715 GDD from bloom to harvest; under our conditions this heat is accumulated over an average of 159 days. Our procedure permits the 'Algerie' harvest date to be estimated with a mean error of 4.4 days (<3% for the bloom-harvest period). GDD summation did not prove superior to the use of the number of calendar days for predicting 'Algerie' harvest under non-limiting growing conditions. However, GDD reflects the developmental rate in water-stressed trees better than calendar days. Trees under deficit irrigation during flower development required more time and more heat to ripen their fruits.


Subject(s)
Climate , Eriobotrya/growth & development , Agriculture , Fruit/growth & development , Seasons , Temperature
16.
J Antimicrob Chemother ; 59(2): 212-8, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17114175

ABSTRACT

OBJECTIVES: Neurocysticercosis is a common parasitic disease in the CNS in humans caused by the metacestode Taenia solium, with high incidence in developing countries. Albendazole is the drug of choice. However, a wide interindividual variability in the response has been reported. In order to evaluate alternative treatment options, the in vitro efficacy of nitazoxanide, its main metabolite tizoxanide as well as the tizoxanide and albendazole sulphoxide combination was tested against Taenia crassiceps cysts. METHODS: T. crassiceps cysts were incubated in culture medium containing different concentrations of nitazoxanide, tizoxanide and albendazole sulphoxide (0.037-0.42 microg/mL). The effect of the tizoxanide and albendazole sulphoxide combination was evaluated in a fixed-concentration ratio (1:1). Isobolographic analyses were used to define the kind of interaction between drugs. Morphological and ultrastructural alterations over the parasite tissue were observed by light and transmission electron microscopy. RESULTS: Nitazoxanide and tizoxanide exhibited cestocidal activity which was time-concentration-dependent. The EC(50) values were 0.15, 0.12 and 0.080 microg/mL for nitazoxanide, tizoxanide and albendazole sulphoxide, respectively. No statistical differences between EC(50) values were found, indicating that nitazoxanide and tizoxanide are equally potent as albendazole sulphoxide. The effect of the tizoxanide and albendazole sulphoxide combination was faster than that observed with each drug alone. Isobolographic analysis showed that the effect of the combination was additive. Nitazoxanide and tizoxanide had an effect on the germinal layer, where lipid droplets were found. Nitazoxanide and tizoxanide produced less damage than albendazole sulphoxide on the germinal layer. After the tizoxanide and albendazole sulphoxide combination, a high accumulation of lipid droplets within the germinal layer of the parasite was found. CONCLUSIONS: Our results suggest that nitazoxanide in combination with albendazole could be useful for treatment of cysticercosis infections. Additional in vivo studies are required to confirm this hypothesis.


Subject(s)
Albendazole/analogs & derivatives , Anticestodal Agents/pharmacology , Cysticercosis/parasitology , Taenia/drug effects , Thiazoles/pharmacology , Albendazole/pharmacology , Animals , Drug Combinations , Drug Synergism , Mice , Mice, Inbred BALB C , Microscopy, Electron, Transmission , Nitro Compounds , Parasitic Sensitivity Tests , Taenia/isolation & purification , Taenia/ultrastructure
17.
Rev. cuba. med. gen. integr ; 8(4): 330-2, oct.-dic. 1992.
Article in Spanish | LILACS | ID: lil-120908

ABSTRACT

Se organizó un subprograma para el pesquisaje de la toxoplasmosis en gestantes al momento de la captación, con la participación de los médicos de la familia y los obstetras de los 4 policlínicos del municipio Manzanillo. Con las pacientes seronegativas se estableció un sistema de vigilancia serológica y se realizó educación higienicosanitaria para evitar una primoinfección. De 2 058 embarazadas, el 84 % no presentó anticuerpos antitoxiplasma detectados por inmunofluorescencia indirecta; 24 de ellas seroconvirtieron y fueron sometidas a tratamiento médico con pirimetamina


Subject(s)
Pregnancy , Humans , Female , Physicians, Family , Toxoplasmosis, Congenital/prevention & control , Cuba
18.
Rev. cuba. med. gen. integr ; 8(4): 330-2, oct.-dic. 1992.
Article in Spanish | CUMED | ID: cum-13319

ABSTRACT

Se organizó un subprograma para el pesquisaje de la toxoplasmosis en gestantes al momento de la captación, con la participación de los médicos de la familia y los obstetras de los 4 policlínicos del municipio Manzanillo. Con las pacientes seronegativas se estableció un sistema de vigilancia serológica y se realizó educación higienicosanitaria para evitar una primoinfección. De 2 058 embarazadas, el 84


no presentó anticuerpos antitoxiplasma detectados por inmunofluorescencia indirecta; 24 de ellas seroconvirtieron y fueron sometidas a tratamiento médico con pirimetamina


Subject(s)
Pregnancy , Humans , Female , Toxoplasmosis, Congenital/prevention & control , Epidemiological Monitoring , Physicians, Family , Cuba
SELECTION OF CITATIONS
SEARCH DETAIL
...