Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
1.
Mol Ecol ; 26(16): 4197-4210, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28570031

RESUMO

Across several animal taxa, the evolution of sociality involves a suite of characteristics, a "social syndrome," that includes cooperative breeding, reproductive skew, primary female-biased sex ratio, and the transition from outcrossing to inbreeding mating system, factors that are expected to reduce effective population size (Ne). This social syndrome may be favoured by short-term benefits but come with long-term costs, because the reduction in Ne amplifies loss of genetic diversity by genetic drift, ultimately restricting the potential of populations to respond to environmental change. To investigate the consequences of this social life form on genetic diversity, we used a comparative RAD-sequencing approach to estimate genomewide diversity in spider species that differ in level of sociality, reproductive skew and mating system. We analysed multiple populations of three independent sister-species pairs of social inbreeding and subsocial outcrossing Stegodyphus spiders, and a subsocial outgroup. Heterozygosity and within-population diversity were sixfold to 10-fold lower in social compared to subsocial species, and demographic modelling revealed a tenfold reduction in Ne of social populations. Species-wide genetic diversity depends on population divergence and the viability of genetic lineages. Population genomic patterns were consistent with high lineage turnover, which homogenizes the genetic structure that builds up between inbreeding populations, ultimately depleting genetic diversity at the species level. Indeed, species-wide genetic diversity of social species was 5-8 times lower than that of subsocial species. The repeated evolution of species with this social syndrome is associated with severe loss of genomewide diversity, likely to limit their evolutionary potential.


Assuntos
Variação Genética , Genética Populacional , Comportamento Social , Aranhas/genética , Animais , Comportamento Animal , Endogamia , Aranhas/classificação
2.
J Evol Biol ; 26(3): 553-61, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23286336

RESUMO

Reproductive partitioning is a key component of social organization in groups of cooperative organisms. In colonies of permanently social spiders of the genus Stegodyphus less than half of the females reproduce, while all females, including nonreproducers, perform suicidal allo-maternal care. Some theoretical models suggest that reproductive skew is a result of contest competition within colonies, leading to size hierarchies where only the largest females become reproducers. We investigated the effect of competition on within-group body size variation over six months in S. dumicola, by manipulating food level and colony size. We found no evidence that competition leads to increased size asymmetry within colonies, suggesting that contest competition may not be the proximate explanation for reproductive skew. Within-colony body size variation was high already in the juvenile stage, and did not increase over the course of the experiment, suggesting that body size variation is shaped at an early stage. This might facilitate task specialization within colonies and ensure colony-level reproductive output by early allocation of reproductive roles. We suggest that reproductive skew in social spiders may be an adaptation to sociality selected through inclusive fitness benefits of allo-maternal care as well as colony-level benefits maximizing colony survival and production.


Assuntos
Tamanho Corporal , Comportamento Competitivo/fisiologia , Comportamento Social , Aranhas/fisiologia , Adaptação Fisiológica , Animais , Comportamento Alimentar/fisiologia , Feminino , Modelos Lineares , Masculino , Reprodução , Especificidade da Espécie , Análise de Sobrevida , Fatores de Tempo
3.
J Evol Biol ; 26(1): 51-62, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23163349

RESUMO

Understanding the social organization of group-living organisms is crucial for the comprehension of the underlying selective mechanisms involved in the evolution of cooperation. Division of labour and caste formation is restricted to eusocial organisms, but behavioural asymmetries and reproductive skew is common in other group-living animals. Permanently, social spiders form highly related groups with reproductive skew and communal brood care. We investigated task differentiation in nonreproductive tasks in two permanently and independently derived social spider species asking the following questions: Do individual spiders vary consistently in their propensity to engage in prey attack? Are individual spiders' propensities to engage in web maintenance behaviour influenced by their previous engagement in prey attack? Interestingly, we found that both species showed some degree of task specialization, but in distinctly different ways: Stegodyphus sarasinorum showed behavioural asymmetries at the individual level, that is, individual spiders that had attacked prey once were more likely to attack prey again, independent of their body size or hunger level. In contrast, Anelosimus eximius showed no individual specialization, but showed differentiation according to instar, where adult and subadult females were more likely to engage in prey attack than were juveniles. We found no evidence for division of labour between prey attack and web maintenance. Different solutions to achieve task differentiation in prey attack for the two species studied here suggest an adaptive value of task specialization in foraging for social spiders.


Assuntos
Comportamento Animal , Comportamento Predatório , Aranhas/fisiologia , Fatores Etários , Animais , Tamanho Corporal/genética , Feminino , Masculino , Especificidade da Espécie
4.
Br J Cancer ; 107(7): 1093-9, 2012 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-22935583

RESUMO

BACKGROUND: This study assessed the safety, tolerability, pharmacokinetics and pharmacodynamics of the first-in-class dual mammalian target of rapamycin complex (mTORC)1/mTORC2 inhibitor, AZD8055. METHODS: Patients with advanced solid malignancies or lymphomas were recruited into this phase I, open-label, dose-escalation study of AZD8055 starting at 10 mg twice-daily oral dosing (BID). RESULTS: Forty-nine patients received AZD8055. Dose-limiting toxicities were reported at 40 mg (n=1), 90 mg (n=1) and 120 mg (n=3) BID; all were grade 3 rises in transaminases, reversible in all patients, apart from one who had liver metastases. The maximum tolerated dose was defined as 90 mg BID. The most frequent adverse events assessed to be related to AZD8055 were increased alanine aminotransferase (22%), increased aspartate aminotransferase (22%) and fatigue (16%). AZD8055 was rapidly absorbed (median t(max) ∼0.5 h) and exposure increased with increasing doses. Seven patients had stable disease for ≥ 4 months. Partial metabolic responses, assessed by fluorodeoxyglucose positron emission tomography, were observed at ≥ 40 mg BID (n=8 at day 35). CONCLUSION: The maximum tolerated dose for AZD8055 is 90 mg BID. Apart from elevated transaminases, which occurred at most dose levels, the drug had an acceptable toxicity profile; however, no RECIST responses were seen.


Assuntos
Linfoma/tratamento farmacológico , Morfolinas/administração & dosagem , Morfolinas/efeitos adversos , Neoplasias/tratamento farmacológico , Adulto , Idoso , Estudos de Coortes , Relação Dose-Resposta a Droga , Esquema de Medicação , Feminino , Humanos , Linfoma/metabolismo , Masculino , Dose Máxima Tolerável , Alvo Mecanístico do Complexo 1 de Rapamicina , Alvo Mecanístico do Complexo 2 de Rapamicina , Pessoa de Meia-Idade , Morfolinas/farmacocinética , Complexos Multiproteicos/antagonistas & inibidores , Neoplasias/metabolismo , Serina-Treonina Quinases TOR/antagonistas & inibidores
5.
Acta Obstet Gynecol Scand ; 78(9): 806-9, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10535346

RESUMO

BACKGROUND: Mifepristone in combination with prostaglandin has been used since 1988 for induction of early abortion. The aim of the present investigation was to assess the tolerance and efficacy of 600 mg. mifepristone orally followed by gemeprost 1 mg. vaginally either 24 hours (group one) or 48 hours (group two) later. METHODS: Sixty-four healthy women applying for abortion within the first 8 weeks of pregnancy were randomly allocated to one of the two treatment groups. Intrauterine pregnancy and gestational age were verified by ultrasonography. Symptoms after administration of mifepristone and gemeprost were recorded, and the patients observed at the hospital for at least three hours after prostaglandin-insertion. Blood samples for blood group, hemoglobin, beta-chorion-gonadotrophin, aspartate-aminotransferase and creatinine were drawn. RESULTS: Outcome was established by gynecological examination, the level of beta-hCG and ultrasonography, at visits one, two and if necessary three to four weeks later. Surgical curettage was performed in case of incomplete abortion, of which there were four in the 24-hour interval group and five in the 48-hour interval group with a success rate (complete abortion) of 55 out of 64 patients (86%). CONCLUSIONS: There was no difference in efficacy or side effects whether the prostaglandin was administered 24 or 48 hours after mifepristone intake, which suggests that the treatment period can be reduced from the conventional 48 hours.


Assuntos
Abortivos não Esteroides/uso terapêutico , Abortivos Esteroides/uso terapêutico , Aborto Induzido/métodos , Alprostadil/análogos & derivados , Mifepristona/uso terapêutico , Dor Abdominal/etiologia , Abortivos não Esteroides/efeitos adversos , Abortivos Esteroides/efeitos adversos , Aborto Induzido/efeitos adversos , Adolescente , Adulto , Alprostadil/efeitos adversos , Alprostadil/uso terapêutico , Quimioterapia Combinada , Feminino , Humanos , Mifepristona/efeitos adversos , Gravidez , Primeiro Trimestre da Gravidez , Fatores de Tempo , Resultado do Tratamento , Hemorragia Uterina/etiologia
6.
Eur J Obstet Gynecol Reprod Biol ; 50(3): 255-7, 1993 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8262304

RESUMO

A case of adenomatoid tumor of the uterus of a 49-year-old woman is described. The tumor was unusually large and atypically located in the fundus of the uterus. Adenomatoid tumors in genitals are benign but may macroscopically resemble a malignant tumor. As recurrence does not occur simple excision is sufficient.


Assuntos
Tumor Adenomatoide/patologia , Neoplasias Uterinas/patologia , Tumor Adenomatoide/cirurgia , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Uterinas/cirurgia
8.
Ugeskr Laeger ; 151(44): 2890-3, 1989 Oct 30.
Artigo em Dinamarquês | MEDLINE | ID: mdl-2588373

RESUMO

The incidence of cervical incompetence is 0.1-1%. A retrospective study of a six year period in the University Hospital of Copenhagen, Hvidovre is presented. This includes 37 women, all of whom were treated surgically on 44 occasions with cerclage on account of incompetence of the cervix. The duration of the pregnancy after operation was longer in women operated in a quiet phase, without cervical effacement and with an internal os smaller than 3 cm. Women with an internal os dilated to more than 3 cm at the time of operation all terminated their pregnancies within three days. This study showed good results if the operation was carried out at a quiet phase, when the internal os was less than 3 cm and when no bulging of the membranes was apparent.


Assuntos
Colo do Útero/cirurgia , Complicações na Gravidez/cirurgia , Incompetência do Colo do Útero/cirurgia , Feminino , Humanos , Recém-Nascido , Ligadura , Métodos , Gravidez , Complicações na Gravidez/prevenção & controle , Estudos Retrospectivos , Incompetência do Colo do Útero/prevenção & controle
9.
J Intern Med ; 226(4): 241-4, 1989 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2809499

RESUMO

Dysfunctions within the hypothalamic-pituitary-gonadal axis occur frequently among women with multiple sclerosis (MS) and may induce menstrual disturbances and subsequent infertility. We have measured serum concentrations of prolactin. gonadotropins and sex hormone binding globulin (SHBG) as well as free and bound oestrogen and androgen levels in 14 women of fertile age with MS. These women all displayed regular cycles without having experienced fertility problems. As controls 14 normal women with regular periods and ideal body weight of 91% (range 80-101) were included. Serum from both groups was sampled during the early follicular phase. The MS-patients had significantly (P less than 0.05) higher concentrations of prolactin, LH, FSH, total and free testosterone (P less than 0.01) and a significantly lower serum concentration of oestrone sulphate (P less than 0.01). The abnormal hormone concentrations were not related to clinical status of the disease. We propose that the increased androgen levels are of ovarian origin as adrenal androgens were normal. The reason for the slight increase of prolactin and the marked increase of gonadotropins in women with MS is speculative. As oestradiol levels, however, were within normal range, we assume that a peripheral resistance to gonadotropins combined with an abnormal central regulation causes the increased pituitary secretion.


Assuntos
Hormônios Esteroides Gonadais/sangue , Gonadotropinas Hipofisárias/sangue , Esclerose Múltipla/sangue , Adulto , Feminino , Humanos , Sistema Hipotálamo-Hipofisário/fisiopatologia , Distúrbios Menstruais/etiologia , Esclerose Múltipla/complicações , Esclerose Múltipla/fisiopatologia , Ovário/fisiopatologia
10.
Fertil Steril ; 52(3): 388-93, 1989 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2776892

RESUMO

The purpose of this investigation was to evaluate all available ovulatory diagnostics with respect to sensitivity, specificity, diagnostic specificity (predictive value of a positive test, PVP) and diagnostic sensitivity (predictive value of a negative test, PVN). Twenty-one ovulatory women with more than 3 years of infertility problems were included in the study. PVP and PVN were highest for detection of urinary luteinizing hormone (LH) peak at ovulation (PVP = 90%, PVN = 95%) and for serum-estradiol peak 1 day before ovulation (PVP = 83%, PVN = 97%). The predictive values were lower for all other tests. The PVP (54%) and PVN (90%) were rather low for detection of ovulation with vaginal electric impedance. However, all ovulations were predicted when urinary LH peak and vaginal impedance were combined. Two women were stimulated with human chorionic gonadotropin to investigate a possible connection between the LH peak and the preovulatory vaginal electric impedance. No close connection between them could be demonstrated. Basal body temperature should not be used for the prediction of ovulation (PVP = 25%). We suggest that ovulation should primarily be predicted from the identification of the urinary LH peak and that other methods be supplementary.


Assuntos
Estradiol/sangue , Hormônio Luteinizante/urina , Ovulação , Análise de Variância , Estudos de Avaliação como Assunto , Feminino , Humanos , Detecção da Ovulação , Indução da Ovulação , Análise de Regressão
11.
Acta Obstet Gynecol Scand ; 66(8): 685-8, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-3448882

RESUMO

The aim of the study was to investigate whether the expulsion of the placenta was delayed among women who had previously undergone induced abortion by suction curettage. We studied the duration of the third stage of labor retrospectively by comparing the third stage of labor, recorded in minutes, between 76 second gravida women with previously induced abortions and 95 second para women with previously uncomplicated pregnancies. The duration of the third stage of labor was also compared among a group of primigravidas and a group of second gravidas with previously induced abortions. We excluded women with previous gynecological disorders (e.g. resulting in curettage of the uterine cavity). All patients included presented normal pregnancies and deliveries resulting in full term (greater than 37 weeks), liveborn infants. By the statistical analysis (analysis of variance and Duncan's test), it could be shown that the 3rd stage of labor lasted significantly longer among women with previously induced abortions (mean: 12 minutes), than among the other groups included in the study (mean: 9 minutes). This discrete difference in length of the third stage of labor need not indicate an altered routine for women, who give birth subsequent to an induced abortion.


Assuntos
Aborto Induzido/efeitos adversos , Terceira Fase do Trabalho de Parto/fisiologia , Trabalho de Parto/fisiologia , Adulto , Feminino , Humanos , Idade Materna , Paridade , Gravidez , Estudos Retrospectivos , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...