Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Insect Physiol ; 53(1): 59-66, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17113098

RESUMO

The L1 contact-chemoreceptor sensillum on the maxillary palp of the spruce budworm larva Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae) was examined electrophysiologically for its responses to stimulation by various pyranose and furanose sugars. The results were compared to those from previous work on the sugar-sensitive neuron of the LST sensillum on the galea. We show that the L1 contact-chemoreceptor sensillum contains one sugar-sensitive neuron with furanose but no pyranose sites. It has response characteristics that differ from those of the sugar-sensitive neuron in the LST. Behavioural 2-choice feeding experiments show that, even with both known sugar-sensitive neurons disabled, larvae can still discriminate between disks treated with either distilled water or alpha-D-glucose. We conclude that the epipharyngeal sensilla must thus also contain a sugar-sensitive neuron.


Assuntos
Carboidratos/farmacologia , Mariposas/anatomia & histologia , Mariposas/fisiologia , Neurônios/efeitos dos fármacos , Animais , Comportamento Animal , Larva/anatomia & histologia , Larva/fisiologia
2.
J Chem Ecol ; 30(11): 2269-83, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15672670

RESUMO

We evaluated the effects of tannic acid and purified perrsimmon tannin on survival and reproduction of bean bugs, Riptortus clavatus.Feeding behavior of R. clavatus was also examined on sweet (cv. Fuyu) and astringent (cv. Chongdosi) persimmon fruits. Soluble tannin in sweet persimmon fruits decreased from 3% in early June to 0.5% in late September, but it increased from 2 to 8% during the same period in astringent persimmon fruits. More bugs visited sweet than astringent persimmon. Numbers of piercing/sucking spots were higher on sweet than on astringent persimmon. When fed 1 and 3% solutions of persimmon tannin, adult bugs ingested only 64.1 and 9.5% of the amount of water ingested by those offered the control (distilled water). Amounts of persimmon tannin ingested by the adult bugs were 6.5 and 2.8 times higher at 1 and 3% tannin solutions compared to a 0.1% solution. Persimmon tannin exerted negative effects on survival and reproduction of R. clavatus at higher concentrations (1 and 3% solutions). Feeding of R. clavatus adults decreased with increasing tannin concentrations. When results from both sexes were pooled, 50% mortality was achieved at 11 and 4 days after treatment with the 1 and 3% tannin solutions, respectively. Reproduction decreased with 1% tannin, and no eggs were produced with 3% tannin solution. Tannic acid was similar in its effects on R. clavatus. All nymphs died 14, 12, and 7 days after feeding on 0.1, 1, and 3% tannic acid, respectively. Adults were less sensitive than nymphs, and their survival was not affected by 0.1% tannic acid. However. 1 and 3% tannic acid solutions were fatal. Survivorship decreased to 50% at 11 and 6 days after supplying tannin solutions of 1 and 3% concentrations. Higher concentrations (1 and 3%) resulted in reduced reproduction, as was seen with persimmon tannin. Our data may explain why R. clavatus does not invade sweet persimmon orchards until late July, when concentrations of soluble tannin are low enough to allow them to feed.


Assuntos
Diospyros/química , Comportamento Alimentar/efeitos dos fármacos , Heterópteros/fisiologia , Reprodução/efeitos dos fármacos , Taninos/farmacologia , Animais , Feminino , Reprodução/fisiologia , Taninos/química , Fatores de Tempo
3.
J Insect Physiol ; 49(8): 733-8, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12880653

RESUMO

The tip of the maxillary palp in the spruce budworm and other lepidoptera larvae contains a cluster of eight basiconic sensilla. Except for a few electrophysiological recordings from the entire group of these sensilla, no information is available on the response characteristics of any individual one. Using a compound microscope at 320x magnification, with a long working-distance objective, it has been possible to view individual sensilla and to record electrical responses from three of these to some gustatory stimuli in preliminary tests. One of them, sensillum (L1), contains a sugar-sensitive neuron whose responses to a range of sucrose concentrations are reported here. The physiological characteristics of this neuron differ from those of the known sugar-sensitive neuron in the lateral styloconic sensillum on the galea of these same insects. Input of chemosensory information about the same gustatory stimulus by more than one neuron in different mouthpart sensilla is discussed in relation to the feeding habits of the spruce budworm.


Assuntos
Lepidópteros/efeitos dos fármacos , Lepidópteros/fisiologia , Neurônios/fisiologia , Sacarose/farmacologia , Animais , Eletrofisiologia , Lepidópteros/ultraestrutura , Neurônios/efeitos dos fármacos , Neurônios/ultraestrutura
4.
J Chem Ecol ; 27(10): 1963-78, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11710605

RESUMO

We investigated the behavioral feeding preference and the chemoreception of leaf polar extracts from trembling aspen, Populus tremuloides, and from sun and shade sugar maple, Acer saccharum, by larvae of the polyphagous forest tent caterpillar, Malacosoma disstria, a defoliator of deciduous forests in the Northern Hemisphere. Three polar extracts were obtained from each tree species: a total extract, a water fraction, and a methanol fraction. M. disstria larvae were allowed ad libitum access to an artificial diet from eclosion to the fifth instar. Two-choice cafeteria tests were performed comparing the mean (+/-SE) surface area eaten of the total extracts, and the following order of preference was obtained: aspen > sun maple > shade maple. Tests with the other fractions showed that M. disstria larvae preferred the total aspen extract to its water fraction, and the latter to its methanol fraction. The response to sun maple was similar to aspen. However, for the shade maple experiment, there was no difference between the total extract and its water fraction. Electrophysiological recordings for aspen showed that the sugar-sensitive cell elicited more spikes to the water fraction, followed by the total extract, and finally the methanol fraction. Spike activity to stimulations of sun and shade maple extracts revealed a similar trend, where methanol fraction > water fraction > total extract. Our findings are discussed in light of previously known information about this insect's performance on these host plants.


Assuntos
Células Quimiorreceptoras/fisiologia , Comportamento Alimentar , Mariposas , Salicaceae/química , Sapindaceae/química , Animais , Carboidratos/farmacologia , Eletrofisiologia , Larva , Extratos Vegetais/farmacologia , Plantas Comestíveis/química , Paladar
5.
Environ Pollut ; 97(3): 303-9, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-15093369

RESUMO

The effects of exposure of sugar maple (Acer saccharum Marsh.) to ozone on the entire larval stage of a native insect have not been previously investigated. This study reports the effects of sugar maple seedlings exposed to different ozone concentrations on the relative performance and the feeding preference of the forest tent caterpillar (Malacosoma disstria Hbn.). Three-year-old seedlings were set in nine open-top field chambers in the spring of 1992 and 1993. Three ozone concentrations were generated: charcoal-filtered ambient air (0x), ambient air (1x) and three times ambient air (3x). In 1992, female and male larval development time did not differ among ozone treatments. In 1993, female larvae reared on 3x developed faster than those on 0x and 1x, while male larvae were not affected. Ozone treatments did not influence pupal weights except for males in 1993 where pupae reared on 0x were heavier than 1x but did not differ from 3x. Larval and pupal survival rates were not affected by ozone in either year. Finally, 4th and 5th instar larvae showed a significant feeding preference for 3x foliage in 1993 but not in 1992. The response of the forest tent caterpillar to ozone exposed seedlings varied between years and could be more sensitive to annual climatic variations than ozone.

6.
Zentralbl Gynakol ; 117(7): 364-7, 1995.
Artigo em Alemão | MEDLINE | ID: mdl-7668067

RESUMO

UNLABELLED: Tubal insufflation with carbon dioxide is one of the ambulatory and non-invasive procedures in use for the evaluation of tubal patency. The aim of the present study was to investigate whether the findings obtained at tubal insufflation are reliable enough to avoid laparoscopy with instillation of dye for its inherent risk of severe operative complications. Diagnostic accuracy, positive and negative predictive value of tubal insufflation were compared with that of the reference method (laparoscopy) in 107 infertile patients of childbearing age without previous pelvic inflammatory disease, tubal or ovarian surgery. No result was obtained from tubal insufflation in 13 patients for intolerance or technical problems. The positive predictive value (percentage of correct positive findings, i.e., tubes patent) was 0.79 (130/165 tubes), the negative predictive value (percentage of correct negative findings) 0.43 (10/23) with an overall diagnostic accuracy (percentage of correct findings) of 0.74. If both tubes were reported patent on insufflation (68 patients), this finding was confirmed in 82% (56/68) on laparoscopy. The remaining 18% also include the rate of false negative findings (tubes falsely reported as occluded) on laparoscopy which may account for up to 10% according to the literature. False negative findings on insufflation were reported at a frequency of 21% (35/165 tubes). COMMENT: The diagnostic accuracy of tubal insufflation with carbon dioxide is definitely inferior to that of laparoscopy. In view of the frequency of false negative findings, its use as a screening procedure should be restricted to young patients with a low probability of tubal occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Dióxido de Carbono , Testes de Obstrução das Tubas Uterinas/métodos , Infertilidade Feminina/etiologia , Adulto , Assistência Ambulatorial , Diagnóstico Diferencial , Feminino , Humanos , Insuflação , Laparoscopia , Valor Preditivo dos Testes
7.
J Chem Ecol ; 20(4): 831-47, 1994 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24242199

RESUMO

Spring and fall adults of the white pine weevil,Pissodes strobi (Peck), were exposed in no-choice and two-choice tests to bark from water-stressed and non-water-stressed white pine (Pinus strobus L.), which had also been exposed or not exposed to weevil attack. This experiment demonstrated that the weevils could discriminate between bark from water-stressed white pine and preferred bark from the nonstressed plants. The weevils also preferred bark from nonstressed plants that were previously exposed to weevil damage. Spring and fall adults displayed the same feeding preferences. No sex differences were found in feeding preferences. Less nitrogen, phosphorus, and potassium were found in bark from the nonstressed plants, and the potassium level was higher in damaged plants. We expect that the biological performance of the weevil should be favored by vigorously growing plants rather than by stressed plants.

9.
Zentralbl Gynakol ; 114(1): 34-6, 1992.
Artigo em Alemão | MEDLINE | ID: mdl-1533983

RESUMO

A case of combined intrauterine and extrauterine pregnancy as rare complication of legally induced abortion is reported. After several ultrasonic examinations, a concomitant ectopic gestation was suspected and subsequently confirmed on laparotomy and on microscopic examination. The early preoperative diagnosis of combined gestation is nowadays mainly based on its exact localisation by vaginal ultrasound. The ultrasonic signs and the predisponsing factors for the development of combined gestation will be discussed.


Assuntos
Aborto Legal , Laparoscopia , Gravidez Tubária/diagnóstico , Gravidez , Adulto , Feminino , Humanos , Gravidez Tubária/cirurgia , Ruptura Espontânea
10.
Gynecol Obstet Invest ; 34(3): 164-70, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1427418

RESUMO

Human chorionic gonadotropin (hCG) exerts a clinically apparent negative feedback on the secretion of human thyroid-stimulating hormone (hTSH) in pregnancy, and the two have cross-reactivity for the TSH receptor in membrane preparations of the thyroid. We examined whether hTSH, in turn, has an influence on the secretion and synthesis of hCG in short-term cultures of human placenta at term. A dose- and time-dependent decrease in the extracellular hCG concentration caused by hTSH was demonstrated. To examine whether hTSH inhibits de novo synthesis of hCG or decreases hCG depletion, we determined the amount of hCG secreted and the size of the intracellular pool by using an enzyme immunoassay. By incorporating a radiolabeled amino acid in the hCG molecule, we measured the amount of hCG synthesized de novo. We concluded that hTSH acts by decreasing the rate of de novo synthesis of placental hCG.


Assuntos
Gonadotropina Coriônica/antagonistas & inibidores , Placenta/metabolismo , Tireotropina/fisiologia , Gonadotropina Coriônica/metabolismo , Regulação para Baixo/fisiologia , Feminino , Humanos , Técnicas Imunoenzimáticas , Técnicas In Vitro , Gravidez , Tireotropina/farmacologia
11.
Gynecol Obstet Invest ; 33(3): 129-33, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1612524

RESUMO

We studied the influence of human prolactin on the secretion and de novo synthesis of human chorionic gonadotropin (hCG) in the human term placenta in culture. Placental tissue from 14 patients with uncomplicated pregnancies and deliveries was prepared mechanically, with addition of a Percoll gradient step. hCG levels were determined in the culture media and in the cytosolic fraction of cells by means of an enzyme immunoassay with coated beads. The amount of newly synthesized hCG was measured by the extent of incorporation of 35S-methionine into the hCG molecule. Our results showed that human prolactin had two different effects in vitro: between 1/2 and 1 h, prolactin slightly increased secretion of hCG into the culture medium without affecting de novo synthesis; after 2 h, prolactin began to cause a significant decrease in both secretion and de novo synthesis of hCG over several hours. It appears that both effects are receptor mediated, for ovine prolactin failed to produce any response. We conclude that prolactin is one of the main factors regulating the synthesis and secretion of hCG in the human trophoblast at term.


Assuntos
Gonadotropina Coriônica/biossíntese , Placenta/metabolismo , Prolactina/farmacologia , Animais , Células Cultivadas , Gonadotropina Coriônica/metabolismo , Técnicas de Cultura , Feminino , Humanos , Técnicas Imunoenzimáticas , Gravidez , Terceiro Trimestre da Gravidez , Ovinos
12.
Gynecol Endocrinol ; 5(4): 235-47, 1991 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1796746

RESUMO

Gonadotropin response to exogenous luteinizing hormone-releasing hormone (LHRH) was studied in two groups of patients with the polycystic ovary syndrome (PCOS). Group I (n = 44) was diagnosed as 'overt PCOS' based on clinical and endocrine abnormalities, and the typical ultrasonic picture of multicystic changes in an increased amount of ovarian stroma. Group II patients (n = 34), with similar clinical and hormonal changes, were classified as 'borderline PCOS' because endosonography of the ovaries was not conclusive. Serum gonadotropins were followed 15, 30, 45 and 60 min after administration of 100 micrograms LHRH intravenously. Plasma LH and the peak ratio of luteinizing hormone to follicle stimulating hormone (LH/FSH peak) after LHRH were significantly higher in Group I and II patients (p less than 0.001) than in controls (n = 11). There was a significant positive correlation between LH (r = 0.73 and 0.68, p less than 0.05) and LH/FSH ratio peaks (r = 0.61 and 0.68, p less than 0.05) after LHRH, and the basal values in each group. However, hyperreactivity of LH and the LH/FSH ratio after LHRH (defined as values exceeding the 95th percentile of control values) was only present in Group I in 38.6 and 56.8%, and in Group II in 47.1 and 73.5% of patients. It is concluded that: exaggerated LH release after LHRH is a typical yet not unique feature of PCOS and its sensitivity is inferior to its specificity; a higher rate for sensitivity is achieved when the LH/FSH ratio after LHRH (instead of LH release alone) is used; and that hyperreactivity of LH after LHRH is neither correlated with the plasma concentrations of total testosterone, free plasma testosterone or androstenedione, nor with the ultrasonic picture of the ovaries as significantly higher (p less than 0.05) LH and LH/FSH ratio peaks were found in borderline PCOS patients. While the heterogeneity of gonadotropin response to LHRH clearly limits its routine diagnostic use, the FSH and LH response is useful in patients with inconsistent clinical and ultrasonic features suggestive of PCOS.


Assuntos
Hormônio Foliculoestimulante/metabolismo , Hormônio Liberador de Gonadotropina , Hormônio Luteinizante/metabolismo , Hipófise/metabolismo , Síndrome do Ovário Policístico/diagnóstico , Adolescente , Adulto , Feminino , Humanos , Cinética , Síndrome do Ovário Policístico/diagnóstico por imagem , Ultrassonografia
13.
Hum Reprod ; 6(9): 1186-91, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1836467

RESUMO

Spontaneous migration of a radionuclide tracer from the vagina to the peritoneum may be visualized by scintigraphic imaging (hysterosalpingoscintigraphy, HSS). A prospective study was designed to evaluate diagnostic criteria for normal tubal passage of a control group (n = 7) and to establish the predictive value of the HSS technique in defining functional deficiency in anatomically patent tubes. In 56 patients with tubal and unexplained infertility, a comparison between the results of the tracer migration study and of contrast hysterosalpingography and laparoscopy was made. The overall correlation was 65%. Clearly discrepant results (i.e. an abnormal migration pattern in anatomically patent tubes) were recorded in 18% and were positively, yet not significantly associated with tubal adhesive disease and with a history of tubal microsurgery. Interpretation of scans was equivocal in another 18% of patients due to undetectable ascension of the tracer to the uterus. It is suggested that the radionuclide is moved forward by the same passive transport processes which are concerned with support of the migration of spermatozoa to the ovum, and that failure of tubal migration of the tracer may render patients eligible for in-vitro fertilization/embryo transfer treatment.


Assuntos
Tubas Uterinas/diagnóstico por imagem , Adulto , Transporte Biológico , Doenças das Tubas Uterinas/diagnóstico por imagem , Doenças das Tubas Uterinas/fisiopatologia , Tubas Uterinas/fisiopatologia , Feminino , Seguimentos , Humanos , Histerossalpingografia , Infertilidade Feminina/diagnóstico por imagem , Infertilidade Feminina/fisiopatologia , Laparoscopia , Valor Preditivo dos Testes , Estudos Prospectivos , Cintilografia/métodos , Aderências Teciduais
16.
Geburtshilfe Frauenheilkd ; 50(6): 488-90, 1990 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-1695883

RESUMO

UNLABELLED: Case of a 20-year-old patient with severe abdominal pain, right adnexal mass, positive beta-HCG titre and free fluid in the abdominal cavity, as diagnosed by ultrasound. Laparotomy resulted in a ruptured ovarian tumour (chorionic carcinoma). Despite chemotherapy, the tumour developed fulminant metastases with a follow-up of 3 months. FINAL DIAGNOSIS: Gonadal dysgenesis, XY female type (Swyer-Syndrome).


Assuntos
Coriocarcinoma/patologia , Disgenesia Gonadal 46 XY/patologia , Disgenesia Gonadal/patologia , Neoplasias Ovarianas/patologia , Adulto , Biomarcadores Tumorais/sangue , Coriocarcinoma/cirurgia , Gonadotropina Coriônica/sangue , Gonadotropina Coriônica Humana Subunidade beta , Feminino , Humanos , Metástase Neoplásica , Neoplasias Ovarianas/cirurgia , Ovariectomia , Ovário/patologia , Fragmentos de Peptídeos/sangue , Ruptura Espontânea
17.
J Chem Ecol ; 14(8): 1649-56, 1988 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24276496

RESUMO

The feeding preferences and feeding rates of eastern spruce budworm on extracts from mature foliage normally avoided by larvae indicate that the chemical composition of four major host plants does not account for this avoidance. Other factors such as the degree of lignification and/or moisture content of the older foliage may play a more important role. Of 14 amino acids tested, alanine, lysine, proline, and serine stimulated feeding. The interactions of amino acids and sucrose were studied, and the results are discussed in relation to feeding preferences and feeding rates.

18.
Arch Gynecol Obstet ; 241(1): 53-6, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-3118825

RESUMO

Ovarian stimulation in patients with disorders of ovulation or an inadequate luteal phase using human menopausal gonadotropins (hMG) gives a low pregnancy rate with a high incidence of overstimulation and a premature LH surge. In order to overcome these problems, a new approach has been used, namely prior suppression of endogenous gonadotropins with a gonadotropin-releasing-hormone analog (LHRH) and subsequent ovarian stimulation with hMG. We present a case of ovarian stimulation with pure FSH during suppression of endogenous gonadotropins with the LHRH analog Buserelin. A clinical pregnancy was achieved in the first treatment cycle and led us to conclude that follicular development does not depend on LH stimulation. This could be of substantial interest in IVF programs.


Assuntos
Busserrelina/farmacologia , Hormônio Foliculoestimulante/farmacologia , Infertilidade Feminina/tratamento farmacológico , Indução da Ovulação/métodos , Adulto , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Humanos , Hormônio Luteinizante/sangue , Ciclo Menstrual/efeitos dos fármacos , Gravidez , Prolactina/sangue
19.
Geburtshilfe Frauenheilkd ; 46(7): 473-4, 1986 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-3758629

RESUMO

This paper presents a case of gonadal dysgenesia with an uncommon structural X-chromosome abnormality (45, X-46, X, ring X mosaicism). The ring chromosome was not derived from an Y-chromosome as excluded by Q-banded analysis. The phenotypic expression of this abnormality caused typical Turner stigmata such as short stature, dysmorphic feature, streak ovaries with hypergonadotropic condition.


Assuntos
Mosaicismo , Síndrome de Turner/genética , Adulto , Feminino , Humanos , Cariotipagem , Ovário/patologia , Síndrome de Turner/patologia
20.
J Chem Ecol ; 11(6): 809-17, 1985 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24310225

RESUMO

Feeding preferences to extracts from three host plants were determined for sixth-instar eastern spruce budworm larvae reared on one of three hosts or on artificial diet. Preferences of foliage-reared larvae were compared to those of diet-reared, or naive, larvae. No effect of plant induction was found using amino acids and bases and chloroform extracts on test disks in three-choice experiments. Possible effects of habituation for sugars and glycosides from white spruce were shown. Organic acids contributed to a phenomenon of avoidance learning in larvae reared on all three hosts, showing that this fraction from balsam fir was the least deterrent, while that from black spruce was the most deterrent.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...