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1.
Clin Radiol ; 77(6): 399-408, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35177229

RESUMO

Castleman Disease (CD) is a rare entity that typically presents as an enhancing nodal mass in the mediastinum or head and neck region on computed tomography (CT). It may manifest as unicentric or multicentric regions of lymph node enlargement. A key clinical issue in the context of CD is delayed diagnosis, which contributes adversely to patient outcome, given that accurate diagnosis facilitates earlier treatment of this curable disease. This article will address relevant imaging aspects, with reference to typical and atypical imaging features of CD, illustrated using examples from our specialist centre; the imaging journey for patients with CD; and will provide practical pointers to radiologists in differentiating CD from other benign and malignant causes of enhancing lymphadenopathy, including lymphoma and neoplastic adenopathy. We will also review current classification tools and staging challenges with reference to World Health Organization guidelines, International Working Group guidelines as well as the Lugano classification. Finally, we will discuss the potential role of additional imaging techniques in CD, highlighting novel imaging methods and expanded utilities from our specialist centre.


Assuntos
Hiperplasia do Linfonodo Gigante , Linfadenopatia , Radiologia , Hiperplasia do Linfonodo Gigante/diagnóstico por imagem , Hiperplasia do Linfonodo Gigante/patologia , Diagnóstico Diferencial , Humanos , Linfadenopatia/diagnóstico por imagem , Radiografia , Tomografia Computadorizada por Raios X
2.
Clin Radiol ; 77(2): 79-87, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34579859

RESUMO

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a rare but emerging T-cell non-Hodgkin lymphoma. It has two distinct subtypes, "effusion-only" or "mass-forming" disease, arising around implants in patients with in situ or previous history of textured-surface breast implants. The clinical, histopathological and imaging features are unique and nuanced as compared to primary breast malignancy and other lymphoma categories. Prompt recognition and diagnosis triggers referral to appropriate BIA-ALCL centres and initiation of treatment, with potential for excellent prognosis. Definitive management of both subtypes involves implant and capsule removal; systemic therapy is reserved for mass-forming disease and advanced-stage disease. There have been recent crucial advances in the diagnostic pathway, with publication of national and international guidelines: from the UK Medicines Healthcare products Regulatory Agency (MHRA) Plastic, Reconstructive and Aesthetic Surgery Expert Advisory Group (PRASEAG), and the United States National Comprehensive Cancer Network (NCCN). This review provides a practical guide to the clinical work-up of BIA-ALCL, enabling optimisation of the diagnostic imaging pathway, with representative cases.


Assuntos
Implantes de Mama/efeitos adversos , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/etiologia , Diagnóstico por Imagem/métodos , Linfoma Anaplásico de Células Grandes/diagnóstico por imagem , Linfoma Anaplásico de Células Grandes/etiologia , Mama/diagnóstico por imagem , Feminino , Humanos , Prognóstico
3.
Clin Radiol ; 76(11): 789-800, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34217434

RESUMO

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia in adults. It is a malignancy of CD5 B-cells characterised by small, mature-appearing lymphocytes accumulating in the blood, bone marrow, and lymphoid tissues. Richer transformation (RT) is an important adverse complication. Detection of RT is critical to allow initiation of appropriate therapy. CLL staging and response evaluation is complicated and nuanced. From our extensive tertiary centre experience of several hundred CLL cases over the last decade, we detail key computed tomography (CT) and positron-emission tomography (PET) imaging features of the natural history of CLL. The authors present an original imaging-based patient-management paradigm for the investigation of potential RT, which will inform global practice. Potential applications of whole-body diffusion weighted imaging, novel PET radiotracers, minimal residual disease, and ct-DNA are addressed.


Assuntos
Leucemia Linfocítica Crônica de Células B/diagnóstico por imagem , Leucemia Linfocítica Crônica de Células B/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Idoso , Progressão da Doença , Humanos , Pessoa de Meia-Idade
4.
Clin Radiol ; 76(5): 391.e1-391.e18, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33579517

RESUMO

Non-Hodgkin's lymphoma (NHL) encompasses over 40 different haematological malignancies, including low and high-grade neoplasms, such as follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) respectively. A key clinical issue in the context of NHL is delayed and inaccurate diagnosis, which contributes adversely to patient morbidity and mortality. This article will address relevant imaging aspects, with particular reference to advancements in NHL imaging, including computed tomography (CT), integrated positron-emission tomography (PET)-CT, and magnetic resonance imaging (MRI). We provide multiparametric (anato-functional) imaging display items, including histological correlation. We will also introduce our original concept of "Specialist Integrated Haematological Malignancy Imaging Reporting" (SIHMIR), a paradigm shift in lymphoma radiology.


Assuntos
Linfoma não Hodgkin/diagnóstico por imagem , Linfoma não Hodgkin/patologia , Imageamento por Ressonância Magnética/métodos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Sistemas de Informação em Radiologia , Tomografia Computadorizada por Raios X/métodos , Humanos , Estadiamento de Neoplasias
5.
J Ovarian Res ; 12(1): 50, 2019 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-31128592

RESUMO

INTRODUCTION: The management of Serous Tubal Intraepithelial Carcinoma (STIC) found at the time of Risk-Reducing Salpingo-Oophorectomy (RRSO) remains unclear. We set out to analyse the incidence of peritoneal carcinomas developed after prophylactic surgery and to formulate further guidance for these patients. METHODS: This is a retrospective study of 300 consecutive RRSO performed at the Royal Marsden Hospital between January 2008 and January 2017. RESULTS: The median age at RRSO was 47.8 years (range 34 to 60 years) and median BMI was 26.2 kg/m2 (range 16 to 51 kg/m2). A total of 273 patients (91%) were tested for BRCA mutations. Of these, 124 (45.4%) had a BRCA 1 mutation, 118 (43.2%) had a BRCA 2 mutation, 2 (0.7%) had both a BRCA 1 and a BRCA 2 mutation and 29 (10.6%) had no BRCA mutation detected. Isolated STIC lesions were identified in 7 cases (2.3%) and p53 signatures in 75 cases (25%). There were five (1.6%) incidental tubal carcinomas and one (0.3%) ovarian carcinoma at the time of surgery. Two (28.6%) of the 7 patients with STIC identified following RRSO had high grade serous peritoneal carcinoma diagnosed at 53 and 75 months. One (0.3%) patient from the other 287 patients from our series with no STIC diagnosis or incidental carcinomas at RRSO developed high grade serous carcinoma of peritoneal origin after 92 months. CONCLUSION: This study demonstrates that when a STIC lesion is identified following RRSO there is a significantly higher risk of a subsequent peritoneal cancer. Although there is no published consensus in literature, we recommend that consideration should be given for long term follow-up if a STIC lesion is identified at RRSO.


Assuntos
Cistadenocarcinoma Seroso/epidemiologia , Cistadenocarcinoma Seroso/secundário , Neoplasias das Tubas Uterinas/patologia , Neoplasias das Tubas Uterinas/cirurgia , Neoplasias Peritoneais/epidemiologia , Neoplasias Peritoneais/secundário , Adulto , Proteína BRCA1/genética , Proteína BRCA2/genética , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/prevenção & controle , Neoplasias das Tubas Uterinas/genética , Feminino , Humanos , Incidência , Pessoa de Meia-Idade , Mutação , Ovariectomia , Neoplasias Peritoneais/genética , Neoplasias Peritoneais/prevenção & controle , Procedimentos Cirúrgicos Profiláticos , Estudos Retrospectivos , Salpingectomia
6.
J Mass Spectrom ; 52(6): 347-352, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28321994

RESUMO

In the past, chrome yellow (lead chromate, PbCrO4 ), a bright orange-red substance, has been widely used as an inorganic pigment in the production of paints, coatings, and plastics. Herein, we demonstrate that laser desorption/ionization mass spectrometry (LDI-MS) is a powerful tool for the detection of lead chromate in solid residues. In fact, lead chromate in trace amounts is easily detectable by LDI-MS even from residues left as latent prints. For example, a latent print obtained by stamping the exposed laterally cut surface of a pencil over 50 years old on an acetonitrile-moistened paper, was successfully imaged for both lead and chromate using a Synapt G2 HDMS mass spectrometer. After rastering the print with a 355 nm laser beam and recording positive- and negative-ion mass spectra over the range m/z 50-1200, we generated false-color 'heat maps' (single-ion images) for 208 Pb+• (m/z 207.98) and Cr2 O6-• (m/z 199.85). The heat maps matched closely with the faint visual image of the pencil imprint. Moreover, our results confirmed that lead chromate was used in the pigment coatings of old pencils. Evidently, LDI-MS imaging is an efficient procedure to survey for the presence of lead and chromate in minerals and other materials. Copyright © 2017 John Wiley & Sons, Ltd.

7.
Br J Cancer ; 109(3): 615-22, 2013 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-23868012

RESUMO

BACKGROUND: Endovaginal MRI (evMRI) at 3.0-T with T2-weighted (T2-W) and ZOnal Oblique Multislice (ZOOM)-diffusion-weighted imaging (DWI) potentially improves the detection of stage Ia/Ib1 cervical cancer. We aimed to determine its sensitivity/specificity, document tumour-to-stromal contrast and establish the effect of imaging on surgical management. METHODS: Following ethical approval and written informed consent, 57 consecutive patients with suspected stage Ia/Ib1 cervical cancer underwent evMRI at 3.0-T using T2-W and ZOOM-DWI. Sensitivity/specificity were calculated against histopathology for two independent observers. Tumour-to-stromal contrast was determined on T2-W, and diffusion-weighted (b=800 s mm(-2)) images and apparent diffusion coefficients (ADCs) were recorded. In patients due for radical vaginal trachelectomy (RVT), change of surgical management based on imaging findings was documented. RESULTS: Sensitivity/specificity for detecting tumour was the following: reporting read 88.0/81.8%, anonymised read 92.0/81.8% (observer 1); 84.0/72.7% (observer2; median tumour volume=1.7 cm(3)). Intraobserver agreement was excellent (kappa=0.89) and the interobserver agreement was good (kappa=0.65). Tumour-to-stromal contrast was greater on ZOOM-DWI compared with T2-W images (3.35±2.36 vs 1.39±0.95; P<0.0004). Tumour and stromal ADCs were significantly different (P<0.00001). In 31 patients due for RVT, evMRI altered surgical management in 12 (38.7%) cases (10 cone-biopsy, 2 chemoradiotherapy). CONCLUSION: T2-W+ZOOM-DWI evMRI has high sensitivity/specificity for detecting stage Ia/Ib1 cervical tumours; in patients due for RVT, the surgical management was altered in ∼39%.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Procedimentos Cirúrgicos em Ginecologia/métodos , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/cirurgia , Adulto , Idoso , Feminino , Preservação da Fertilidade/métodos , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Sensibilidade e Especificidade
8.
Leukemia ; 22(6): 1139-43, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18401419

RESUMO

Peripheral T-cell lymphomas (PTCLs) are fatal in the majority of patients and novel treatments, such as protein tyrosine kinase (PTK) inhibition, are needed. The recent finding of SYK/ITK translocations in rare PTCLs led us to examine the expression of Syk PTK in 141 PTCLs. Syk was positive by immunohistochemistry (IHC) in 133 PTCLs (94%), whereas normal T cells were negative. Western blot on frozen tissue (n=6) and flow cytometry on cell suspensions (n=4) correlated with IHC results in paraffin. Additionally, western blot demonstrated that Syk-positive PTCLs show tyrosine (525/526) phosphorylation, known to be required for Syk activation. Fluorescence in situ hybridization showed no SYK/ITK translocation in 86 cases. Overexpression of Syk, phosphorylation of its Y525/526 residues and the availability of orally available Syk inhibitors suggest that Syk merits further evaluation as a candidate target for pharmacologic PTK inhibition in patients with PTCL.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Linfoma de Células T Periférico/enzimologia , Proteínas Tirosina Quinases/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Western Blotting , Criança , Pré-Escolar , Cromossomos Humanos Par 5/genética , Cromossomos Humanos Par 9/genética , Feminino , Citometria de Fluxo , Humanos , Técnicas Imunoenzimáticas , Imunofenotipagem , Hibridização in Situ Fluorescente , Peptídeos e Proteínas de Sinalização Intracelular/genética , Linfoma Extranodal de Células T-NK/enzimologia , Linfoma Extranodal de Células T-NK/genética , Linfoma Extranodal de Células T-NK/patologia , Linfoma Anaplásico de Células Grandes/enzimologia , Linfoma Anaplásico de Células Grandes/genética , Linfoma Anaplásico de Células Grandes/patologia , Linfoma Cutâneo de Células T/enzimologia , Linfoma Cutâneo de Células T/genética , Linfoma Cutâneo de Células T/patologia , Linfoma de Células T Periférico/genética , Linfoma de Células T Periférico/patologia , Masculino , Pessoa de Meia-Idade , Fosforilação , Proteínas Tirosina Quinases/genética , Quinase Syk , Translocação Genética , Tirosina/metabolismo
9.
Histopathology ; 50(4): 498-508, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17448026

RESUMO

AIMS: To identify distinguishing histological, immunophenotypic and molecular genetic features between angioimmunoblastic T-cell lymphoma (AITL) and peripheral T-cell lymphoma (PTL). METHODS: Nodal T-cell lymphomas examined (n =137), included AITL (n = 89), PTL (n = 22), anaplastic large cell lymphoma (n = 16) and 'AITL/PTL indeterminate' (n = 10) with overlapping features between AITL and PTL, showing morphology typical of AITL but lacking follicular dendritic cell expansion. Immunohistochemistry for CD3, CD20, CD21 and CD10, in situ hybridization for Epstein-Barr virus encoded RNA (EBER) and polymerase chain reaction for T-cell and B-cell clonality analysis were performed. RESULTS: Of the AITLs, 74/89 showed typical morphology, whereas 15/89 showed hyperplastic follicles. AITL and 'AITL/PTL indeterminate' showed a polymorphous infiltrate and prominent vascularity in all cases. In both groups, CD10 was present in the majority and clear cells and EBER positivity were specific (but not universal) features lacking in PTL. Detection of T-cell clonality was significantly higher in AITL (90%) compared with PTLu (59%). CONCLUSION: Clear cells and EBV infection (when present) are useful distinguishing features and CD10 a sensitive and specific marker of AITL. Hyperplastic follicles are present in a significant minority of AITL. AITL/PTL indeterminate probably falls within the spectrum of AITL rather than PTL.


Assuntos
Linfadenopatia Imunoblástica/diagnóstico , Linfoma de Células T Periférico/diagnóstico , Antígenos CD20/metabolismo , Linfócitos B/patologia , Complexo CD3/metabolismo , Células Clonais , Diagnóstico Diferencial , Rearranjo Gênico , Herpesvirus Humano 4/genética , Humanos , Linfadenopatia Imunoblástica/genética , Linfadenopatia Imunoblástica/patologia , Cadeias Pesadas de Imunoglobulinas/genética , Imuno-Histoquímica , Imunofenotipagem , Linfoma de Células T Periférico/genética , Linfoma de Células T Periférico/patologia , Neprilisina/metabolismo , Reação em Cadeia da Polimerase , RNA Viral/análise , Receptores de Antígenos de Linfócitos T gama-delta/genética , Receptores de Complemento 3d/metabolismo , Sensibilidade e Especificidade , Linfócitos T/patologia
10.
J Chem Ecol ; 32(12): 2687-94, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17077999

RESUMO

The acceptance of Solanum surattenses as a host plant for the larvae of Manduca sexta was explained by the presence of feeding stimulants in foliage. Bioassay-guided fractionation of plant extracts resulted in the isolation of a highly active compound (1), which was identified as a furostan derivative {26-O-beta-D-glucopyranosyl-(25R)-furosta-5-ene-3-beta-yl-O-alpha-L-rhamnopyranosyl-(1''-2')-O-alpha-L-rhamnopyranosyl-(1'''-3'')-O-beta-D-glucopyranoside}. This compound has the same steroidal core substructure as that in a stimulant (indioside D) previously identified from potato foliage. However, the sugar substituents attached to the core are different.


Assuntos
Comportamento Alimentar/efeitos dos fármacos , Manduca/efeitos dos fármacos , Oligossacarídeos/isolamento & purificação , Solanum/química , Animais , Glicosídeos , Larva , Manduca/fisiologia , Oligossacarídeos/química , Oligossacarídeos/farmacologia , Extratos Vegetais/química , Esteroides , Estimulação Química
11.
Proc Natl Acad Sci U S A ; 98(24): 13745-50, 2001 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-11707571

RESUMO

The flower of Hypericum calycinum, which appears uniformly yellow to humans, bears a UV pattern, presumably visible to insects. Two categories of pigments, flavonoids and dearomatized isoprenylated phloroglucinols (DIPs), are responsible for the UV demarcations of this flower. Flavonoids had been shown previously to function as floral UV pigments, but DIPs had not been demonstrated to serve in that capacity. We found the DIPs to be present in high concentration in the anthers and ovarian wall of the flower, suggesting that the compounds also serve in defense. Indeed, feeding tests done with one of the DIPs (hypercalin A) showed the compound to be deterrent and toxic to a caterpillar (Utetheisa ornatrix). The possibility that floral UV pigments fulfill both a visual and a defensive function had not previously been contemplated. DIPs may also serve for protection of female reproductive structures in other plants, for example in hops (Humulus lupulus). The DIPs of hops are put to human use as bitter flavoring agents and preservatives in beer.


Assuntos
Hypericum/fisiologia , Repelentes de Insetos , Feromônios/fisiologia , Floroglucinol , Pigmentos Biológicos/fisiologia , Animais , Hypericum/química , Repelentes de Insetos/química , Estrutura Molecular , Mariposas , Feromônios/química , Floroglucinol/química , Pigmentos Biológicos/química , Raios Ultravioleta
12.
J Chem Ecol ; 27(8): 1575-83, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11521397

RESUMO

The host plants of the native American butterfly, Pieris napi oleracea, include most wild mustards. However, garlic mustard, Alliaria petiolata, a highly invasive weed that was introduced from Europe, appears to be protected from this insect. Although adults will oviposit on the plant, most larvae of P. n. oleracea do not survive on garlic mustard. We used feeding bioassays with different larval stages of the insect to monitor the isolation and identification of two bioactive constituents that could explain the natural resistance of this plant. A novel cyanopropenyl glycoside (1), alliarinoside, strongly inhibits feeding by first instars, while a flavone glycoside (2), isovitexin-6"-D-beta-glucopyranoside, deters later instars from feeding. Interestingly, the first instars are insensitive to 2, and the late instars are little affected by 1. Furthermore, differential effects of dietary experience on insect responses suggest that 1 acts through a mechanism of post-ingestive inhibition, whereas 2 involves gustatory deterrence of feeding.


Assuntos
Brassicaceae/química , Lepidópteros , Plantas Comestíveis/fisiologia , Animais , Bioensaio , Glucosídeos/isolamento & purificação , Glucosídeos/farmacologia , Glicosídeos/isolamento & purificação , Glicosídeos/farmacologia , Larva/crescimento & desenvolvimento , Nitrilas/isolamento & purificação , Nitrilas/farmacologia , Oviposição , Análise de Sobrevida
13.
J Chem Ecol ; 27(5): 907-17, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11471943

RESUMO

In wind-tunnel bioassays, dispensers loaded with 1 microg of the synthetic major component (3E,8Z, 11Z)-3,8,11-tetradecatrienyl acetate (TDTA) of the sex pheromone emitted by Tuta absoluta (Meyrick) females were found to be highly attractive to conspecific males. Field experiments were conducted to evaluate the efficacy of five trap designs. The best trap, baited with 100 microg of the synthetic sex pheromone caught on average 1,200 males per trap per night, while those baited with virgin females caught only 201 males. The male response to this pheromone is restricted to the same early-morning time window during which females exhibit calling behavior. The high biological activity of the synthetic pheromone suggests that it could be useful for pest monitoring and in mating disruption.


Assuntos
Acetatos/farmacologia , Álcoois Graxos/farmacologia , Mariposas/fisiologia , Atrativos Sexuais/farmacologia , Animais , Bioensaio , Feminino , Masculino , Controle de Pragas , Dinâmica Populacional , Comportamento Sexual Animal , Olfato
14.
J Nat Prod ; 64(4): 440-3, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11325224

RESUMO

Alliarinoside, a feeding inhibitor against early instar larvae of Pieris napi oleracea, was isolated from the foliage of Alliaria petiolata and characterized as (2Z)-4-(beta-D-glucopyranosyloxy)-2-butenenitrile (1) by spectroscopic methods. The structural assignment was confirmed by synthesis of peracetylated alliarinoside (2) and its 2E isomer (3). A sample of synthetic 1 was isolated by preparative HPLC from the hydrolysis of the 2Z acetate. Feeding inhibition assays showed comparable activity for the synthetic and natural glycosides.


Assuntos
Brassicaceae/química , Comportamento Alimentar/efeitos dos fármacos , Glucosídeos/farmacologia , Larva/efeitos dos fármacos , Nitrilas/farmacologia , Animais , Glucosídeos/química , Glucosídeos/isolamento & purificação , Insetos/crescimento & desenvolvimento , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Nitrilas/química , Nitrilas/isolamento & purificação , Espectrometria de Massas por Ionização por Electrospray
15.
Rapid Commun Mass Spectrom ; 14(13): 1105-9, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10867684

RESUMO

Mass spectral fragmentation pathways of four doubly unsaturated aldehyde N,N-dimethylhydrazones were investigated using EI-MS and tandem mass spectrometry (MS/MS) under electron ionization and collisionally activated decomposition (CAD) conditions. Cyclopentene extrusion was found to be slightly favored over cyclohexene loss in a hydrazone capable of losing either cycloalkene. Evidence for the regeneration of a chain-shortened iminium radical cation as a result of cycloalkene extrusion was provided by studying substrates capable of undergoing successive cycloalkene budding sequences. EI-MS of these compounds shows sequential loss of both cyclopentene and cyclohexene, in accord with expectations for a cascade mechanism. Although these MS/MS experimental results are also compatible with alternative mechanisms which would entail the simultaneous loss of both neutral cycloalkenes or of a macrocyclic diene, a rapid cascade of cycloalkene budding accounts best for the experimental observations.


Assuntos
Alcenos/química , Hidrazonas/síntese química , Ciclização , Cromatografia Gasosa-Espectrometria de Massas , Hidrazonas/química , Indicadores e Reagentes , Espectroscopia de Ressonância Magnética
16.
J Exp Biol ; 203(Pt 8): 1265-75, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10729276

RESUMO

The bombardier beetle Metrius contractus discharges its defensive secretion as a froth that clings to its body. When attacked from the rear, it allows the froth to build up over the gland openings near the abdominal tip; when attacked from the front, it conveys the secretion forwards along special elytral tracks. M. contractus has two-chambered defensive glands typical of bombardier beetles, and its secretion, like that of other bombardiers, is quinonoid and hot. Its frothing mechanism, however, is unique for bombardiers and possibly illustrative of the ancestral glandular discharge mechanism of these beetles. M. contractus, thus, could be the least derived of extant bombardiers.


Assuntos
Besouros/fisiologia , Animais , Comportamento Animal , Benzoquinonas/análise , Benzoquinonas/metabolismo , Evolução Biológica , Besouros/anatomia & histologia , Glândulas Exócrinas/anatomia & histologia , Glândulas Exócrinas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos/análise , Microscopia Eletrônica de Varredura , Quinonas/análise
17.
Proc Natl Acad Sci U S A ; 96(22): 12251-6, 1999 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-10535907

RESUMO

The African dwarf crocodile, Osteolaemus tetraspis (Crocodilidae, Reptilia), possesses a pair of skin glands, the paracloacal glands, the secretion of which is thought to be used to mark nest sites or attract mates. Ten aromatic steroidal esters were isolated from this secretion and characterized on the basis of NMR spectroscopic investigations, electrospray ionization-MS analyses, and chemical degradation. These esters, which account for more than 90% of the paracloacal glandular secretion, are derived from either cholesterol or cholestanol, esterified with a C-20 or C-22 acid closely related to dianeackerone, the only significant volatile compound found in this secretion.


Assuntos
Jacarés e Crocodilos/metabolismo , Cetonas/química , Pele/metabolismo , Esteroides/química , Animais , Ésteres , Cetonas/metabolismo , Espectroscopia de Ressonância Magnética , Estrutura Molecular
18.
J Nat Prod ; 62(1): 179-80, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9917315

RESUMO

The new compound 6'''-O-sinapoylisovitexin 6'' -O-beta-D-glucopyranoside (1) was isolated from the foliage of Alliaria petiolata, and identified by spectral studies.


Assuntos
Brassicaceae/química , Glucosídeos/isolamento & purificação , Sequência de Carboidratos , Glucosídeos/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas/métodos , Dados de Sequência Molecular , Estrutura Molecular , Espectrofotometria Ultravioleta
19.
Proc Natl Acad Sci U S A ; 95(23): 13387-91, 1998 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-9811809

RESUMO

The pupal defensive secretion of the 24-pointed ladybird beetle, Subcoccinella vigintiquatuorpunctata, consists of a mixture of macrocyclic polyamines, dominated by the three dimeric, 30-membered macrocycles 11-13, derived from the two building blocks 11-(2-hydoxyethylamino)-5-tetradecenoic acid (9) and 11-(2-hydoxyethylamino)-5,8-tetradecadienoic acid (10). Smaller amounts of the four possible cyclic trimers of 9 and 10 were also detected, corresponding to 45-membered macrocycles. Structural assignments were based on NMR-spectroscopic investigations and HPLC-MS analyses. In addition, the all-S absolute configuration of the S. vigintiquatuorpunctata macrocycles was determined by comparison of derivatives of the natural material with enantiomerically pure synthetic samples. Comparing this alkaloid mixture with that of the pupal defensive secretion in related ladybird beetle species indicates that the degree of oligomerization of the 2-hydroxyethylamino carboxylic acid building blocks can be carefully controlled by the insects.


Assuntos
Alcaloides/química , Besouros/química , Animais , Dimerização , Ácidos Graxos Insaturados/química
20.
Science ; 281(5375): 428-31, 1998 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-9665888

RESUMO

The pupal defensive secretion of the coccinellid beetle Epilachna borealis is composed principally of a combinatorial library of macrocyclic polyamines. These compounds constitute a previously unrecognized family of natural products, characterized by extremely large-ring lactonic structures derived from a small set of (2-hydroxyethylamino)alkanoic acids. The combinatorial assembly of these simple building blocks generates a high degree of structural diversity, which is further increased by slow, spontaneous intramolecular rearrangement of the macrocycles.


Assuntos
Aminoácidos/química , Besouros/química , Poliaminas/química , Aminoácidos/análise , Aminoácidos/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Besouros/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Isomerismo , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Poliaminas/análise , Poliaminas/isolamento & purificação , Poliaminas/metabolismo , Poliésteres/análise , Poliésteres/química , Poliésteres/metabolismo , Pupa/química , Pupa/metabolismo
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