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1.
J Exp Biol ; 226(19)2023 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-37827114

RESUMEN

Animals face unpredictable challenges that require rapid, facultative physiological reactions to support survival but may compromise reproduction. Bats have a long-standing reputation for being highly sensitive to stressors, with sensitivity and resilience varying both within and among species, yet little is known about how stress affects the signaling that regulates reproductive physiology. Here, we provide the first description of the molecular response of the hypothalamic-pituitary-gonadal (HPG) axis of male big brown bats (Eptesicus fuscus) in response to short-term stress using a standardized restraint manipulation. This acute stressor was sufficient to upregulate plasma corticosterone and resulted in a rapid decrease in circulating testosterone. While we did not find differences in the mRNA expression of key steroidogenic enzymes (StAR, aromatase, 5-alpha reductase), seminiferous tubule diameter was reduced in stressed bats coupled with a 5-fold increase in glucocorticoid receptor (GR) mRNA expression in the testes. These changes, in part, may be mediated by RFamide-related peptide (RFRP) because fewer immunoreactive cell bodies were detected in the brains of stressed bats compared with controls - suggesting a possible increase in secretion - and increased RFRP expression locally in the gonads. The rapid sensitivity of the bat testes to stress may be connected to deleterious impacts on tissue health and function as supported by significant transcriptional upregulation of key pro-apoptotic signaling molecules (Bax, cytochrome c). Experiments like this broadly contribute to our understanding of the stronger ecological predictions regarding physiological responses of bats within the context of stress, which may impact decisions surrounding animal handling and conservation approaches.


Asunto(s)
Quirópteros , Animales , Masculino , Quirópteros/fisiología , Neuroendocrinología , Reproducción/fisiología , Gónadas , ARN Mensajero
2.
J Comp Neurol ; 530(9): 1459-1469, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-34957555

RESUMEN

Gonadotropin-inhibitory hormone (GnIH, also known RFRP-3 in mammals) is an important regulator of the hypothalamic-pituitary-gonadal axis and downstream reproductive physiology. Substantial species differences exist in the localization of cell bodies producing RFRP-3 and patterns of fiber immunoreactivity in the brain, raising the question of functional differences. Many temperate bat species exhibit unusual annual reproductive patterns. Male bats upregulate spermatogenesis in late spring which is asynchronous with periods of mating in the fall, while females have the physiological capacity to delay their reproductive investment over winter via sperm storage or delayed ovulation/fertilization. Neuroendocrine mechanisms regulating reproductive timing in male and female bats are not well-studied. We provide the first description of RFRP-precursor peptide of GnIH -expression and localization in the brain of any bat using a widespread temperate species (Eptesicus fuscus, big brown bat) as a model. RFRP mRNA expression was detected in the hypothalamus, testes, and ovaries of big brown bats. Cellular RFRP-immunoreactivity was observed within the periventricular nuclei, dorsomedial nucleus of the hypothalamus, arcuate nucleus (Arc), and median eminence (ME). As in other vertebrates, RFRP fiber immunoreactivity was widespread, with the greatest density observed in the hypothalamus, preoptic area, Arc, ME, midbrain, and thalamic nuclei. Putative interactions between RFRP-ir fibers and gonadotropin-releasing hormone (GnRH) cell bodies were observed in 16% of GnRH-immunoreactive cells, suggesting direct regulation of GnRH via RFRP signaling. This characterization of RFRP distribution contributes to a deeper understanding of bat neuroendocrinology, which serves as foundation for manipulative approaches examining changes in reproductive neuropeptide signaling in response to environmental and physiological challenges within, and among, bat species.


Asunto(s)
Quirópteros , Neuropéptidos , Animales , Núcleo Arqueado del Hipotálamo/metabolismo , Quirópteros/metabolismo , Femenino , Hormona Liberadora de Gonadotropina/análisis , Gonadotropinas/análisis , Gonadotropinas/metabolismo , Masculino , Neuropéptidos/metabolismo
3.
Proc Biol Sci ; 287(1929): 20200842, 2020 06 24.
Artículo en Inglés | MEDLINE | ID: mdl-32546100

RESUMEN

The emergency life-history stage (ELHS) can be divided into two subcategories that describe distinct, coordinated responses to disease- or non-disease-related physiological challenges. Whether an individual can simultaneously express aspects of both subcategories when faced with multiple challenges is poorly understood. Emergency life-history theory suggests that disease- and non-disease-related responses are coordinated at the level of the whole organism and therefore cannot be expressed simultaneously. However, the reactive scope and physiological regulatory network models suggest that traits can be independently regulated, allowing for components of both disease- and non-disease-related responses to be simultaneously expressed within a single organism. To test these ideas experimentally, we subjected female zebra finches to food deprivation, an immune challenge, both, or neither, and measured a suite of behavioural and physiological traits involved in the ELHS. We examined whether the trait values expressed by birds experiencing simultaneous challenges resembled trait values of birds experiencing a single challenge or if birds could express a mixture of trait values concurrently. We find that birds can respond to simultaneous challenges by regulating components of the behavioural and immune responses independently of one another. Modularity within these physio-behavioural networks adds additional dimensions to how we evaluate the intensity or quality of an ELHS. Whether modularity provides fitness advantages or costs in nature remains to be determined.


Asunto(s)
Pinzones/fisiología , Animales , Corticosterona , Femenino , Privación de Alimentos , Conducta de Enfermedad , Estadios del Ciclo de Vida , Masculino
4.
Gen Comp Endocrinol ; 292: 113438, 2020 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-32060003

RESUMEN

Food deprivation or restriction causes animals to mount a stereotypical behavioral and physiological response that involves overall increases in activity, elevated glucocorticoid production, and (often) inhibition of the reproductive system. Although there is increasing evidence that these responses can differ in their degree or covariation between the sexes, most studies to-date on food restriction/deprivation have focused on male songbirds. We therefore aimed to characterize the behavioral, physiological, and neuroendocrine response to acute food deprivation in a female songbird using a nomadic species, the zebra finch. We quantified behavior during a 6.5 h food deprivation and then measured physiological and neuroendocrine responses of female birds at the 6.5 h timepoint. Within 1 h of acute food deprivation, female zebra finches increased foraging behaviors, and after 6.5 h of food deprivation, females lost 5% of their body mass, on average. Change in body mass was positively associated with elevated corticosterone and (contrary to findings in male zebra finches) negatively related to the number of gonadotropin inhibitory hormone-immunoreactive cells in the hypothalamus. However, there was no effect of food deprivation on corticotropin releasing hormone-immunoreactive cells in the hypothalamus. There was also no relationship between corticotropin releasing hormone-immunoreactive cell number and circulating corticosterone. Our results are consistent with the hypothesis that neuroendocrine responses to food deprivation differ between male and female songbirds. Future studies should work to incorporate sex comparisons to evaluate sex-specific neuroendocrine responses to acute stress.


Asunto(s)
Hormona Liberadora de Corticotropina/metabolismo , Pinzones/fisiología , Alimentos , Hormonas Hipotalámicas/metabolismo , Hipotálamo/metabolismo , Animales , Recuento de Células , Femenino , Privación de Alimentos , Masculino , Fenotipo
5.
Mil Med ; 185(Suppl 1): 423-429, 2020 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-32074337

RESUMEN

INTRODUCTION: The aim of this study was to quantify the extent of donor-cell-derived myogenesis achieved by a novel surgical technique known as Minimally Invasive Muscle Embedding (MIME). MATERIALS AND METHODS: Through MIME, we implanted a single extensor digitorum longus muscle from donor mice (N = 2) that expressed a red fluorescent protein (RFP), into the left tibialis anterior (TA) muscle of immunodeficient host mice (N = 4) that expressed a green fluorescent protein (GFP). Soon after MIME, we injected a myotoxin (barium chloride), into the host TA muscle, to trigger concerted muscle degeneration and regeneration. In lieu of MIME, we performed a SHAM procedure on the right TA muscle of the same set of animals. RESULTS: In MIME-treated muscles, 22% ± 7% and 78% ± 7% muscle fibers were RFP+ and GFP+, respectively (mean ± standard deviation); and all RFP+ fibers were positive for desmin and dystrophin. Conclusion. We conclude that MIME helps generate muscle fibers of donor origin, in host muscle.


Asunto(s)
Desmina/análisis , Distrofina/análisis , Fibras Musculares Esqueléticas/trasplante , Adhesión del Tejido/métodos , Animales , Modelos Animales de Enfermedad , Ratones , Ratones SCID , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Adhesión del Tejido/estadística & datos numéricos
6.
Mol Cancer Ther ; 15(1): 60-71, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26637366

RESUMEN

Exportin1 (XPO1; also known as chromosome maintenance region 1, or CRM1) controls nucleo-cytoplasmic transport of most tumor suppressors and is overexpressed in many cancers, including multiple myeloma, functionally impairing tumor suppressive function via target mislocalization. Selective inhibitor of nuclear export (SINE) compounds block XPO1-mediated nuclear escape by disrupting cargo protein binding, leading to retention of tumor suppressors, induction of cancer cell death, and sensitization to other drugs. Combined treatment with the clinical stage SINE compound selinexor and the irreversible proteasome inhibitor (PI) carfilzomib induced synergistic cell death of myeloma cell lines and primary plasma cells derived from relapsing/refractory myeloma patients and completely impaired the growth of myeloma cell line-derived tumors in mice. Investigating the details of SINE/PI-induced cell death revealed (i) reduced Bcl-2 expression and cleavage and inactivation of Akt, two prosurvival regulators of apoptosis and autophagy; (ii) intracellular membrane-associated aggregation of active caspases, which depended on caspase-10 protease activity; and (iii) novel association of caspase-10 and autophagy-associated proteins p62 and LC3 II, which may prime activation of the caspase cascade. Overall, our findings provide novel mechanistic rationale behind the potent cell death induced by combining selinexor with carfilzomib and support their use in the treatment of relapsed/refractory myeloma and potentially other cancers.


Asunto(s)
Apoptosis/efectos de los fármacos , Caspasa 10/metabolismo , Hidrazinas/farmacología , Mieloma Múltiple/metabolismo , Oligopéptidos/farmacología , Triazoles/farmacología , Animales , Antineoplásicos/farmacología , Autofagia/efectos de los fármacos , Caspasa 8/metabolismo , Línea Celular Tumoral , Modelos Animales de Enfermedad , Sinergismo Farmacológico , Activación Enzimática/efectos de los fármacos , Humanos , Espacio Intracelular , Ratones , Inhibidores de Proteasoma/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto
7.
Br J Haematol ; 170(1): 66-79, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25824111

RESUMEN

Toward our goal of personalized medicine, we comprehensively profiled pre-treatment malignant plasma cells from multiple myeloma patients and prospectively identified pathways predictive of favourable response to bortezomib-based treatment regimens. We utilized two complementary quantitative proteomics platforms to identify differentially-regulated proteins indicative of at least a very good partial response (VGPR) or complete response/near complete response (CR/nCR) to two treatment regimens containing either bortezomib, liposomal doxorubicin and dexamethasone (VDD), or lenalidomide, bortezomib and dexamethasone (RVD). Our results suggest enrichment of 'universal response' pathways that are common to both treatment regimens and are probable predictors of favourable response to bortezomib, including a subset of endoplasmic reticulum stress pathways. The data also implicate pathways unique to each regimen that may predict sensitivity to DNA-damaging agents, such as mitochondrial dysfunction, and immunomodulatory drugs, which was associated with acute phase response signalling. Overall, we identified patterns of tumour characteristics that may predict response to bortezomib-based regimens and their components. These results provide a rationale for further evaluation of the protein profiles identified herein for targeted selection of anti-myeloma therapy to increase the likelihood of improved treatment outcome of patients with newly-diagnosed myeloma.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Mieloma Múltiple/tratamiento farmacológico , Mieloma Múltiple/patología , Células Plasmáticas/metabolismo , Células Plasmáticas/patología , Adulto , Anciano , Ácidos Borónicos/administración & dosificación , Bortezomib , Dexametasona/administración & dosificación , Doxorrubicina/administración & dosificación , Doxorrubicina/análogos & derivados , Humanos , Lenalidomida , Persona de Mediana Edad , Mieloma Múltiple/metabolismo , Polietilenglicoles/administración & dosificación , Medicina de Precisión/métodos , Proteómica/métodos , Pirazinas/administración & dosificación , Talidomida/administración & dosificación , Talidomida/análogos & derivados
8.
J Chemother ; 19(5): 570-6, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18073157

RESUMEN

To investigate the therapeutic value and safety of the biweekly regimen of 5-fluorouracil (5-FU) and leucovorin (LV) plus irinotecan (CPT-11) in patients with previously untreated advanced gastric cancer (AGC). A total of 50 patients (M/F 35/15; median age = 65) with AGC, none of whom had received chemotherapy for advanced disease, were accrued in this trial. Fifteen patients (30%) were 70 years old or older. At the time of their accrual, cytotoxic chemotherapy, consisting of LV 100 mg/m(2) (2-hour i.v. infusion) followed by 5-FU 400 mg/m(2) (bolus) and 5-FU 600 mg/m(2) (22-hour continuous infusion) on therapeutic days 1 and 2 plus CPT-11 180 mg/m(2) (1-hour infusion) on day 1, was initiated. Treatment courses were repeated every 2 weeks until evidence of progressive disease, unacceptable toxicity or withdrawal of consent. All patients were assessable for toxicity and 48 of 50 for response evaluation, having completed at least four courses of chemotherapy. Complete response was achieved in 2 patients (4%, intent to treat) and partial response in 16 (32%) (overall response rate, 36%; 95% confidence interval [CI]: 22%-50%). Twenty-four patients (48%) had stable disease and 6 patients (16%) progressed. The median time to progression was 8 months (95% CI: 6-10 months) and median overall survival 14 months (95% CI: 6-22 months). Between the subgroups of patients <70 years old and 70 or older, there were no significant differences in efficacy. One toxic death occurred. Treatment tolerance was generally mild to moderate and easy to treat. The main grade 3/4 toxicities were neutropenia (32%), diarrhea (16%), and anemia (8%). Grade 3-4 neutropenia was the only treatment-related serious adverse event significantly more common in patients older than those aged <70 (53.3% vs 22.8%, respectively; P = 0.03). Our data suggest that the biweekly regimen of LV and 5-FU plus CPT-11 in untreated patients with AGC is active and has an acceptable safety profile. Further evaluation of this regimen seems to be warranted in a phase III trial.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Gástricas/tratamiento farmacológico , Adenocarcinoma/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Camptotecina/administración & dosificación , Camptotecina/efectos adversos , Camptotecina/análogos & derivados , Supervivencia sin Enfermedad , Femenino , Fluorouracilo/administración & dosificación , Fluorouracilo/efectos adversos , Humanos , Irinotecán , Estimación de Kaplan-Meier , Leucovorina/administración & dosificación , Leucovorina/efectos adversos , Masculino , Persona de Mediana Edad , Neoplasias Gástricas/mortalidad , Resultado del Tratamiento
11.
Environ Toxicol Chem ; 20(10): 2198-204, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11596751

RESUMEN

The fate of chlordane and other persistent organic pollutants in the environment is of international concern. The behavior of persistent organic pollutants under both abiotic and biotic conditions must be determined for the comprehensive elucidation of their cycling through the biosphere. Standard analytical methods such as gas chromatography with electron capture detection are adequate for studies of cycling under abiotic conditions. Since two of the main components of technical chlordane, cis-chlordane and trans-chlordane, are optically active, chiral gas chromatography can be used to study the impact of biotic influences on chlordane's fate. We report here the use of chiral gas chromatography interfaced with ion trap mass spectrometry as part of an analytically rigorous method for the simultaneous determination of the compositional and chiral profiles of weathered soil residues of technical chlordane. Using the method described, several patterns in the long-term weathering of technical chlordane in soil are observed.


Asunto(s)
Clordano/química , Insecticidas/química , Contaminantes del Suelo/análisis , Fenómenos Químicos , Química Física , Monitoreo del Ambiente , Cromatografía de Gases y Espectrometría de Masas
12.
Clin Ter ; 152(1): 39-50, 2001.
Artículo en Italiano | MEDLINE | ID: mdl-11382169

RESUMEN

Epithelial ovarian carcinoma represents a prototypic example of neoplastic disease sharing at the same time good chemosensitivity as well as marked propensity to relapse. If in one hand the definition of almost clear-cut guidelines has been reached in the setting of first-line therapy (i.e., cytoreductive surgery followed by first-line chemotherapy), more difficult to discern for the oncologist remains the choice of treatment in the occasion(s) of relapse(s). This article focuses on this particular setting of disease, analyzing the specific criteria of choice of drug or their combinations; the definite criteria followed for the use of platinum compounds in the second line of treatment, even if already utilized in the front line therapy, are also analyzed. Specific attention has also been paid in the definition of the role of single parameter as a "prognosticator" and/or as "predictor" of response. The Authors emphasize how clinical definitions remain the more reliable, simple, reproducible tools in therapeutical decision making.


Asunto(s)
Antineoplásicos/uso terapéutico , Neoplasias Ováricas/tratamiento farmacológico , Antineoplásicos/sangre , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Antígeno Ca-125/sangre , Femenino , Humanos , Recurrencia Local de Neoplasia , Neoplasias Ováricas/sangre , Pronóstico
13.
Med Hypotheses ; 56(4): 442-7, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11339844

RESUMEN

The ideal computerized mammogram processing system still needs to be developed. In order to achieve maximum flexibility we suggest a modular scheme, dividing the processing sequence into functionally autonomous modules. This paper provides a general scheme for detection and/or automated recognition of microcalcifications. Some modules that perform ROI selection are introduced, using special non-linear filters designed for microcalcification detection. A first type of filter selects pixels with specific statistical local features, as compared to the local mean. Among these, only pixels satisfying particular constraints on the local standard deviation are kept. Another type of filter then checks the local mean values of gradient components, so that sharp variations, unrelated to small close objects, can be eliminated. The scheme thus applies different non-linear filters in combination, making precise identification of clustered microcalcifications possible. This modular approach seems greatly to simplify system maintenance and consistency, as well as affording a comparison of different processing techniques and parameters.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Calcinosis , Diagnóstico por Computador , Mamografía/métodos , Algoritmos , Humanos
14.
J Agric Food Chem ; 48(10): 4666-70, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11052716

RESUMEN

In 1997 this laboratory initiated a research program with the objective of examining the effect that rinsing of produce with tap water would have on pesticide residues. Samples were obtained from local markets and/or grown at our experimental farm. Because approximately 35% of produce from retail sources contains pesticide residues, growing and treating produce at an experimental farm had the advantage that all such samples contain pesticide residues. Pesticides were applied under normal field conditions to a variety of food crops and the vegetation was allowed to undergo natural weathering prior to harvest. The resulting samples contained field-incurred or "field-fortified" residues. This experimental design was employed to mimic as closely as possible real world samples. Crops were treated, harvested, and divided into equal subsamples. One subsample was processed unwashed, whereas the other was rinsed under tap water. The extraction and analysis method used was a multi-residue method developed in our laboratory. Twelve pesticides were included in this study: the fungicides captan, chlorothalonil, iprodione, and vinclozolin; and the insecticides endosulfan, permethrin, methoxychlor, malathion, diazinon, chlorpyrifos, bifenthrin, and DDE (a soil metabolite of DDT). Statistical analysis of the data using the Wilcoxon signed-rank test showed that rinsing removed residues for nine of the twelve pesticides studied. Residues of vinclozolin, bifenthrin, and chlorpyrifos were not reduced. The rinsability of a pesticide is not correlated with its water solubility.


Asunto(s)
Contaminación de Alimentos/prevención & control , Residuos de Plaguicidas/análisis , Cromatografía de Gases , Manipulación de Alimentos , Indicadores y Reactivos
15.
Clin Ter ; 151(1): 29-35, 2000.
Artículo en Italiano | MEDLINE | ID: mdl-10822879

RESUMEN

Medullary thyroid carcinoma (MTC) originates in the thyroid C cells, or parafollicular cells, secreting calcitonin. It may be either sporadic or familial. Familial form can be isolated or expression of a multiple endocrine neoplasia type II. Mutations of the RET proto-oncogene have been identified in the germline DNA of patients with familial MTC syndromes. Genetic testing can identify patients affected by multiple endocrine neoplasia and familial MTC, allowing early diagnosis and possible cure. The initial treatment is surgical and the adequate surgery consists of total thyroidectomy. The treatment of occult or minimal disease can be curative. Plasma calcitonin measurements are excellent markers for post-operative follow-up. Imaging study can help to discover recurrent or metastatic disease. Adjunctive therapy includes radiotherapy and chemotherapy. Radiotherapy is reserved for bone metastases or for non resectable neck recurrences. Chemotherapy is reserved for patients with progressive MTC. Many chemotherapeutic regimens have been tried, results are controversial.


Asunto(s)
Carcinoma Medular/diagnóstico , Carcinoma Medular/terapia , Neoplasias de la Tiroides/diagnóstico , Neoplasias de la Tiroides/terapia , Calcitonina/sangre , Carcinoma Medular/genética , Pruebas Genéticas , Humanos , Neoplasia Endocrina Múltiple Tipo 2b/clasificación , Neoplasia Endocrina Múltiple Tipo 2b/genética , Proteínas de Neoplasias/sangre , Pronóstico , Proto-Oncogenes Mas , Neoplasias de la Tiroides/genética , Tiroidectomía
16.
J Agric Food Chem ; 48(5): 1909-15, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10820114

RESUMEN

Chlordane is a member of the persistent organic pollutants (POPs), a group of chemicals characterized by extremely long residence in the environment after application. Technical chlordane, composed of a large number of components, is a synthetic organochlorine substance that was used primarily as an insecticide. Uptake by root crops of persistent soil residues of chlordane was noted early in the chronology of the material. The present report is the first comprehensive study of the uptake of weathered soil residues of chlordane and its translocation throughout the tissues of food crops under both greenhouse and field conditions. The data show that for all 12 crops chlordane is not limited to root tissue but is translocated from the root to some of the aerial tissues. Chlordane accumulation in edible aerial tissue appears to be dependent on plant physiology. As expected, chlordane was detected in the edible root tissue of the three root crops examined, carrots, beets, and potatoes. In the remaining crops chlordane was detected in the edible aerial tissue of spinach, lettuce, dandelion, and zucchini, whereas it was not detected in edible aerial tissue of tomatoes, peppers, and corn; trace amounts of chlordane were detected in the edible aerial tissue of bush beans and eggplant. Under the conditions of the field trial the data indicate that for weathered chlordane residues, the soil-to-plant uptake route dominates over the air-to-plant uptake route. This is the case even when the soil concentration of the recalcitrant, weathered residues, for which volatilization is expected to be minimal, is as high as it would be directly following application. Greenhouse trials confirm this observation for zucchini, a member of the Cucurbitaceae family, which bioaccumulates weathered chlordane very efficiently in its edible fruits.


Asunto(s)
Clordano/farmacocinética , Productos Agrícolas/metabolismo , Insecticidas/farmacocinética , Transporte Biológico
17.
J Chromatogr A ; 679(2): 269-75, 1994 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-7951994

RESUMEN

Needles from ornamental yews (Taxus spp.) are known to contain significant amounts of the anticancer agent Taxol (paclitaxel), as well as other analogous taxane compounds. Methanol extracts the taxanes from the needles efficiently, but the crude methanolic extract contains large amounts of co-extractives in addition to the taxanes of interest. The crude extract may be fractionally partitioned using C18 solid-phase extraction (SPE), permitting the collection of a fraction in which the taxanes elute quantitatively. This fraction can then be analyzed directly by means of high-performance liquid chromatography. We have successfully scaled-up the quantity of crude extract partitioned by means of the SPE technique, using larger SPE cartridges prepared in our laboratory as well as using Empore extraction disks. SPE using the Empore disks permits us to collect large quantities of the taxane fraction for studies on its cytostatic effect on non-mammalian eukaryotic cells.


Asunto(s)
Cromatografía Líquida de Alta Presión , Paclitaxel/aislamiento & purificación , Árboles/química , Paclitaxel/análogos & derivados , Plantas Medicinales/química , Espectrofotometría Ultravioleta
18.
J Chem Ecol ; 17(2): 451-62, 1991 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24258737

RESUMEN

Bobcat (Lynx rufus) urine reduces scent-marking activity of woodchucks (Marmota monax) and feeding activity of snowshoe hares (Lepus americanus) and deer (Odocoileus virginianus, O. hemionus). In order to identify the semiochemicals responsible for these behavior modifications, a dichloromethane extract of the bobcat urine was analyzed by GC-MS. Among the known compounds identified in the extract are phenol, indole, dimethyl sulfone, and 3-mercapto-3-methylbutanol. Compounds for which spectroscopic data are presented for the first time include one sulfide, two disulfides, and two trisulfides. The sulfur compounds are derived from an amino acid,S-(l,1-dimethyl-3-hydroxypropyl)cysteine ("felinine"), which was identified several years ago in the urine of the domestic cat (Felis domesticus).

19.
J Chem Ecol ; 17(4): 767-77, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24258921

RESUMEN

We tested whether predator odors could reduce winter browsing of woody plants by white-tailed deer (Odocoileus virginianus). Urine from bobcats (Lyra rufus) and coyotes (Canis latrans) significantly reduced browsing of Japanese yews (Taxus cuspidata), and repellency was enhanced when urine was reapplied weekly as a topical spray. Urine of cottontail rabbits (Sylvilagus floridanus) and humans did not reduce damage, suggesting that deer do not respond aversively to odors of nonpredatory mammals or occasional predators with which they lack a long evolutionary association. Bobcat and coyote urine were more effective in tests conducted with eastern hemlock (Tsuga canadensis), which is less palatable to white-tailed deer than Japanese yew. A dichloromethane extract of bobcat urine was as effective as unextracted urine in reducing damage to hemlocks. Testing of the organic components of bobcat urine, particularly the volatile components, may enable identification of the compounds responsible for the repellency we observed.

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