Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
1.
Osteoarthritis Cartilage ; 29(2): 208-214, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33232804

RESUMO

BACKGROUND: Colchicine may offer relief in osteoarthritis. This has never been investigated for hand osteoarthritis. OBJECTIVES: To investigate the effect of 1 mg daily colchicine vs placebo on hand pain and function over 12 weeks in older adults with hand osteoarthritis. METHODS: Community-dwelling adults with diagnosed osteoarthritis of the hand aged 40-80 years were randomised to receive colchicine (0.5 mg twice daily) or matching placebo. Primary outcome measure was VAS hand pain score (0-100 mm). Secondary outcome measures included tender and swollen joint count, grip strength, C-reactive protein, and Michigan Hand Questionnaire total, function and pain scores. In an exploratory assessment, we compared synovial grade and power Doppler. All outcome measures were obtained at baseline and week 12. Stata v16 was used to perform constrained longitudinal data analysis models. RESULTS: 64 adults (54 females, 10 males) aged 48-79 years of age were enrolled. 59 participants completed the study (N = 28 colchicine, N = 31 placebo) (withdrawal rate 8%). Adverse reactions to the study medication occurred in nine patients. VAS score was not significantly different at baseline (61 ± 17 mm in the colchicine, 64 ± 17 mm in the placebo group). Between-group difference for VAS score at week 12 was 7.6 mm (95% CI -3.5-18.7, p-value 0.18). There were no significant differences between groups for any secondary outcomes at baseline or week 12. CONCLUSIONS: 1 mg colchicine daily for 12 weeks was not effective for reducing pain, tender and swollen joint count or increasing grip strength in symptomatic hand osteoarthritis. Our results do not support the use of colchicine in hand osteoarthritis.


Assuntos
Artralgia/tratamento farmacológico , Colchicina/uso terapêutico , Supressores da Gota/uso terapêutico , Articulação da Mão/fisiopatologia , Osteoartrite/tratamento farmacológico , Idoso , Artralgia/fisiopatologia , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite/fisiopatologia , Medição da Dor
2.
J Evol Biol ; 29(11): 2229-2241, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27423061

RESUMO

The sex-ratio X-chromosome (SR) is a selfish chromosome that promotes its own transmission to the next generation by destroying Y-bearing sperm in the testes of carrier males. In some natural populations of the fly Drosophila neotestacea, up to 30% of the X-chromosomes are SR chromosomes. To investigate the molecular evolutionary history and consequences of SR, we sequenced SR and standard (ST) males at 11 X-linked loci that span the ST X-chromosome and at seven arbitrarily chosen autosomal loci from a sample of D. neotestacea males from throughout the species range. We found that the evolutionary relationship between ST and SR varies among individual markers, but genetic differentiation between SR and ST is chromosome-wide and likely due to large chromosomal inversions that suppress recombination. However, SR does not consist of a single multilocus haplotype: we find evidence for gene flow between ST and SR at every locus assayed. Furthermore, we do not find long-distance linkage disequilibrium within SR chromosomes, suggesting that recombination occurs in females homozygous for SR. Finally, polymorphism on SR is reduced compared to that on ST, and loci displaying signatures of selection on ST do not show similar patterns on SR. Thus, even if selection is less effective on SR, our results suggest that gene flow with ST and recombination between SR chromosomes may prevent the accumulation of deleterious mutations and allow its long-term persistence at relatively high frequencies.


Assuntos
Evolução Biológica , Razão de Masculinidade , Cromossomo X , Animais , Drosophila/genética , Feminino , Masculino , Recombinação Genética
3.
Heredity (Edinb) ; 112(4): 454-62, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24326291

RESUMO

Pigmentation is a rapidly evolving trait that is under both natural and sexual selection in many organisms. In the quinaria group of Drosophila, nearly all of the 30 species have an abdomen that is light in color with distinct markings; D. tenebrosa is the exception in that it has a completely melanic abdomen with no visible markings. In this study, we use a combination of quantitative genetic and candidate gene approaches to investigate the genetic basis of abdominal pigmentation in D. tenebrosa. We find that abdominal pigmentation is invariant across wild-caught lines of D. tenebrosa and is not sexually dimorphic. Quantitative genetic mapping utilizing crosses between D. tenebrosa and the light-colored D. suboccidentalis indicates that two genomic regions together underlie abdominal pigmentation, including the X-chromosome and an autosome (Muller Element C/E). Further support for their central importance in pigmentation is that experimental introgression of one phenotype into the other species, in either direction, results in introgression of these two genomic regions. Finally, the expression of the X-linked gene yellow in the pupae exactly foreshadows the adult melanization pattern in the abdomen of both species, suggesting that changes in the regulation of yellow are important for the phenotypic divergence of D. tenebrosa from the rest of the quinaria group. These results contribute to a body of work that demonstrates how changes in expression of highly conserved genes can cause substantial phenotypic differences even between closely related species.


Assuntos
Drosophila/genética , Genoma , Pigmentação/genética , Abdome/anatomia & histologia , Animais , Ligação Genética , Genótipo , Dados de Sequência Molecular
4.
J Evol Biol ; 26(8): 1646-54, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23663194

RESUMO

Behavioural adaptations of hosts to their parasites form an important component of the evolutionary dynamics of host-parasite interactions. As mushroom-feeding Drosophila can tolerate deadly mycotoxins, but their Howardula nematode parasites cannot, we asked how consuming the potent mycotoxin α-amanitin has affected this host-parasite interaction. We used the fly D. putrida and its parasite H. aoronymphium, which is both highly virulent and at high prevalence in some populations, and investigated whether adult flies utilize food with toxin to prevent infection in the next generation or consume the toxin to reduce the virulence of an already established infection. First, we found that uninfected females did not prefer to eat or lay their eggs on toxic food, indicating that selection has not acted on the flies to alter their behaviour towards α-amanitin to prevent their offspring from becoming infected by Howardula. However, we cannot rule out that flies use an alternate cue that is associated with toxin presence in the wild. Second, we found that infected females did not prefer to eat food with α-amanitin and that consuming α-amanitin did not cure or reduce the virulence of the parasite in adults that were already infected. In sum, our results indicate there are no direct effects of eating α-amanitin on this host-parasite interaction, and we suggest that toxin tolerance is more likely maintained by selection due to competition for resources than as a mechanism to avoid parasite infection or to reduce the virulence of infection.


Assuntos
Alfa-Amanitina , Drosophila/parasitologia , Comportamento Alimentar , Interações Hospedeiro-Parasita , Tylenchida/fisiologia , Animais , Feminino , Masculino
5.
J Evol Biol ; 21(6): 1570-7, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18717746

RESUMO

Maternally transmitted male-killing endosymbionts can exert strong and relentless selection pressure on their hosts to evolve resistance to these infections. Surveys of current infection prevalence and mtDNA diversity indicate that Drosophila innubila is and has been infected with male-killing Wolbachia at moderate frequencies for extended evolutionary periods. Here, we use coalescent simulations to infer the minimum age of the Wolbachia infection in this species, and estimate that the infection is at least 15,000 and perhaps over 700,000 years old. We also surveyed this species for genetic variation for resistance to the male-killing effects of infection. Our surveys revealed no evidence for any resistance polymorphism, such that all flies are completely susceptible to male killing. Given the general assumption that Drosophila can be selected for anything, the lack of resistance, despite thousands of years of strong selection, is an apparent evolutionary conundrum. We hypothesize that resistance requires a mutation of major effect that acts early in development, and that the adverse pleiotropic consequences of such mutations in both infected and uninfected individuals may exceed the possible benefit to infected flies.


Assuntos
Drosophila/genética , Drosophila/microbiologia , Wolbachia/fisiologia , Animais , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Variação Genética , Interações Hospedeiro-Patógeno/fisiologia , Masculino , Razão de Masculinidade
6.
J Med Internet Res ; 3(2): E23, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11720965

RESUMO

Knowledge and capabilities, particularly of a new technology or in a new area of study, frequently develop faster than the guidelines and principles needed for practitioners to practice ethically in the new arena; this is particularly true in medicine. The blending of medicine and healthcare with e-commerce and the Internet raises many questions involving what sort of ethical conduct should be expected by practitioners and developers of the medical Internet. Some of the early pioneers in medical and healthcare Web sites pushed the ethical boundaries with questionable, even unethical, practices. Many involved with the medical Internet are now working to reestablish patient and consumer trust by establishing guidelines to determine how the fundamentals of the medical code of ethical conduct can best be adapted for the medical/healthcare Internet. Ultimately, all those involved in the creation, maintenance, and marketing of medical and healthcare Web sites should be required to adhere to a strict code of ethical conduct, one that has been fairly determined by an impartial international organization with reasonable power to regulate the code. This code could also serve as a desirable, recognizable label-of-distinction for ethical Web sites within the medical and healthcare Internet community. One challenge for those involved with the medical and healthcare Internet will be to determine what constitutes "Medical Internet Ethics" or "Healthcare Internet Ethics," since the definition of medical ethics can vary from country to country. Therefore, the emerging field of Medical/ Healthcare Internet Ethics will require careful thought and insights from an international collection of ethicists in many contributing areas. This paper is a review of the current status of the evolving field of Medical/Healthcare Internet Ethics, including proposed definitions and identification of many diverse areas that may ultimately contribute to this multidisciplinary field. The current role that medicine and health play in the growing area of Internet communication and commerce and many of the ethical challenges raised by the Internet for the medical community are explored and some possible ways to address these ethical challenges are postulated.


Assuntos
Ética Médica , Saúde , Internet/tendências , Animais , Humanos
7.
Stud Health Technol Inform ; 84(Pt 2): 1287-91, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11604935

RESUMO

As in any new field, the merger of medicine, e-commerce and the Internet raises many questions pertaining to ethical conduct. Key issues include defining the essence of the patient-provider relationship, establishing guidelines and training for practicing online medicine and therapy, setting standards for ethical online research, determining guidelines for providing quality healthcare information and requiring ethical conduct for medical and health websites. Physicians who follow their professional code of ethics are obligated not to exploit the relationship they have with patients, nor allow anyone else working with them to do so. Physicians and therapists are obligated to serve those who place trust in them for treatment, whether in face-to-face or online Internet encounters with patients or clients. This ethical responsibility to patients and clients is often in direct conflict with the business model of generating profits. Healthcare professionals involved in Medical Internet Ethics need to define the scope of competent medical and healthcare on the Internet. The emerging ethical issues facing medicine on the Internet, the current state of medical ethics on the Internet and questions for future directions of study in this evolving field are reviewed in this paper.


Assuntos
Ética Médica , Internet , Confidencialidade , Ética Profissional , Humanos , Relações Médico-Paciente , Pesquisa
8.
Am J Med ; 99(3): 321-2, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-7653494
10.
West J Med ; 164(1): 81-2, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8779218

RESUMO

The patient, a 43-year-old man with insulin-dependent diabetes mellitus, presented four days after sustaining a dog bite on his right hand, complaining of excruciating, intermittent, right thigh pain. He was febrile (temperature, 38.3 degrees C [101 degrees F]) and had a leukocyte count of 27.8 x 10(9) per liter (27,800 per mm3). On physical examination, he had a 2-cm open wound with minimal purulent drainage on the fourth digit of his right hand. He had some limited range of motion of the right hip and focal muscular tenderness in the medial thigh, but no other infectious or neurologic findings. A radiographic evaluation included chest, lumbar, right femur, and pelvic films and a computed tomographic (CT) scan of the abdomen; all were normal. In addition, a nuclear medicine scan showed no signs of infection. A CT scan and a magnetic resonance image (MRI) of the pelvis were done (Figures 1 and 2).


Assuntos
Neurilemoma/diagnóstico , Neoplasias Pélvicas/diagnóstico , Adulto , Febre/etiologia , Humanos , Leucocitose/etiologia , Imageamento por Ressonância Magnética , Masculino , Dor/etiologia , Coxa da Perna , Tomografia Computadorizada por Raios X
11.
Dev Biol ; 84(2): 425-31, 1981 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20737881

RESUMO

Cytophotometric and cell sorter analysis of Feulgen-stained nuclei of the dorsal abdominal epidermis of the tobacco hornworm Manduca sexta through the final larval instar showed that both 2C and 4C populations were present. A transient population of octaploid cells (30%) was seen on Day 3 at the time of the ecdysteroid-directed reprogramming of the cells for metamorphosis. This specific replication was found to occur in vitro, irrespective of whether the cells were incubated in 20-hydroxyecdysone to induce the change to pupal commitment or in hormone-free media during which they retain their commitment to make larval cuticle. Cytosine arabinoside (1 and 10 microg/ml) inhibited cell cycling during the time of the change of commitment but did not prevent the ecdysteroid-directed change. Thus, DNA synthesis is coincident with, but not necessary for, the genetic reprogramming of Manduca larval epidermis.


Assuntos
DNA/biossíntese , Epiderme/metabolismo , Manduca/embriologia , Metamorfose Biológica , Animais , Células Cultivadas , DNA/análise , Citometria de Fluxo
12.
Nature ; 400(6743): 449-52, 1999 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-10440373

RESUMO

Females in almost all animal groups copulate with multiple males. This behaviour allows different males to compete for fertilization and gives females the opportunity to mediate this competition. In many animals and most insects, the second male to copulate with a female typically sires most of her offspring. In Drosophila melanogaster, this second-male sperm precedence has long been studied but, as in most species, its mechanism has remained unknown. Here we show, using labelled sperm in doubly mated females, that males can both physically displace and incapacitate stored sperm from earlier-mating males. Displacement occurs only if the second male transfers sperm to the female, and in only one of her three sperm-storage organs. Incapacitation can be caused by either fertile or spermless second males, but requires extended intervals between matings. Sperm from different males are not 'stratified' in the storage organs but mix freely. Many animal species may have multiple mechanisms of sperm competition like those observed here, and revealing these mechanisms is necessary to understand the genetic and evolutionary basis of second-male sperm precedence in animals.


Assuntos
Drosophila/fisiologia , Espermatozoides/fisiologia , Animais , Sobrevivência Celular , Cor de Olho/genética , Feminino , Fertilização/fisiologia , Proteínas de Fluorescência Verde , Proteínas Luminescentes/genética , Masculino , Modelos Biológicos , Seleção Genética , Comportamento Sexual Animal , Especificidade da Espécie
13.
Cytogenet Cell Genet ; 50(2-3): 116-20, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2776476

RESUMO

A fluorescence in situ hybridization method using a biotinylated DNA probe specific for the centromeric region of the human X chromosome was used to differentiate the genetically active from the inactive X in interphase cells. With this technique, we were able to interpret both the relative position and the degree of condensation of the X chromosomes within the nucleus. We first established the specificity of fluorescence labelling of the hybridized probe by comparing its location and appearance (either dense or diffuse) when associated with a sex chromatin body (SCB) in early passage normal human female fibroblasts. In these cells, where the presence of inactive X chromatin was verified by identification of a 4',6-diamidino-2-phenyl indole (DAPI)-positive SCB in 85% of the cells examined, the X chromatin fluorescence was always associated with the SCB. The signal was dense in structure in 98% and peripheral in location in 80% of the nuclei. A second type of signal, diffuse in form, was observed in 85% of the nuclei and presumably represents the location of the active X chromosome. It was located peripherally or centrally with equal frequency and was not associated with any identifiable nuclear component. This diffuse signal was the major type associated with human male fibroblasts. In rodent x human hybrid cells containing a human inactive X, the fluorescent signal was associated with an SCB-like structure in only 13% of the nuclei; it was dense in 66% of the nuclei and equally peripheral or central in location. This indicates an alteration in the interphase structure of the human inactive X chromosome in hybrid cells which may explain its known instability with respect to genetic activity in such systems.


Assuntos
Mecanismo Genético de Compensação de Dose , Cromossomo X/ultraestrutura , Animais , Cricetinae , Sondas de DNA , Feminino , Fluorescência , Humanos , Células Híbridas , Interfase , Masculino , Camundongos
14.
Chromosoma ; 92(3): 209-13, 1985.
Artigo em Inglês | MEDLINE | ID: mdl-3893932

RESUMO

Nick translation assays of fixed interphase female fibroblasts with tritiated nucleotides demonstrated a characteristic absence of label over sex chromatin. The chromatin bodies were nearly always peripheral in location and a ribbon of nick translatable DNA was detected between the sex chromatin and the nuclear envelope. High voltage electron microscopy indicated the possibility of a special nuclear envelope attachment region. The apparent resistance of sex chromatin to nick translation did not appear to be due to resistance to DNase I attack.


Assuntos
Biossíntese de Proteínas , Cromossomo X/ultraestrutura , Células Cultivadas , Cromatina/ultraestrutura , DNA Polimerase Dirigida por DNA/metabolismo , Escherichia coli/enzimologia , Feminino , Fibroblastos/citologia , Humanos , Interfase , Microscopia Eletrônica , Nucleotídeos de Timina/metabolismo , Trítio , Cromossomo X/metabolismo
15.
Development ; 99(1): 137-43, 1987 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-3652987

RESUMO

The relative DNA content of Manduca sexta abdominal epidermal nuclei during the final larval instar was measured by cytophotometry of whole-mount preparations of the epidermis. In the middle intrasegmental region, epidermal cells showed a ploidy level of 4C to 32C on the day of ecdysis. During the subsequent period of feeding, the proportion of higher ploidy cells, such as 16C and 32C, increased. This situation remained until the day of apolysis preceding pupal cuticle formation when mitoses reduced the cells to 2C, 4C, 8C and 16C, except for the pupal pock-mark cells, which increased to 32C or 64C. Metaphase cells showed various ploidy levels, correlated with the size of their mitotic figures. By contrast, in the anterior and posterior margin of a segment where no mitoses occurred, the cells continued to increase in ploidy throughout the instar.


Assuntos
Lepidópteros/genética , Ploidias , Animais , Núcleo Celular/análise , DNA/análise , Células Epidérmicas , Epiderme/análise , Larva/análise , Metáfase , Mitose
16.
Hum Genet ; 65(2): 207-8, 1983.
Artigo em Inglês | MEDLINE | ID: mdl-6686210

RESUMO

A cloned cDNA probe encoding human factor IX was used for detecting homologous sequences in rodent human X chromosome hybrids and in human metaphase chromosome preparations. The results of these studies indicate that human factor IX is localized to the Xq27 leads to Xqter region.


Assuntos
Fator IX/genética , Hibridização Genética , Cromossomo X , Animais , DNA/genética , Feminino , Humanos , Roedores
17.
Proc Natl Acad Sci U S A ; 91(13): 5858-62, 1994 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-8016078

RESUMO

Chromosome-specific DNA libraries can be very useful in molecular and cytogenetic genome mapping studies. We have developed a rapid and simple method for the generation of chromosome-specific DNA sequences that relies on polymerase chain reaction (PCR) amplification of a single flow-sorted chromosome or chromosome fragment. Previously reported methods for the development of chromosome libraries require larger numbers of chromosomes, with preparation of pure chromosomes sorted by flow cytometry, generation of somatic cell hybrids containing targeted chromosomes, or a combination of both procedures. These procedures are labor intensive, especially when hybrid cell lines are not already available, and this has limited the generation of chromosome-specific DNA libraries from nonhuman species. In contrast, a single sorted chromosome is a pure source of DNA for library production even when flow cytometric resolution of chromosome populations is poor. Furthermore, any sorting cytometer may be used with this technique. Using this approach, we demonstrate the generation of PCR libraries suitable for both molecular and fluorescence in situ hybridization studies from individual baboon and canine chromosomes, separate human homologues, and a rearranged marker chromosome from a transformed cell line. PCR libraries specific to subchromosomal regions have also been produced by sorting a small chromosome fragment. This simple and rapid technique will allow generation of nonhuman linkage maps and probes for fluorescence in situ hybridization and the characterization of marker chromosomes from solid tumors. In addition, allele-specific libraries generated by this strategy may also be useful for mapping genetic diseases.


Assuntos
Mapeamento Cromossômico , Cromossomos Humanos Par 8 , Cromossomos Humanos , Cães/genética , Biblioteca Gênica , Linfócitos/fisiologia , Papio/genética , Reação em Cadeia da Polimerase , Animais , Linhagem Celular , Linhagem Celular Transformada , DNA/genética , DNA/isolamento & purificação , DNA/metabolismo , DNA Satélite/genética , Citometria de Fluxo , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Linfócitos/citologia , Papillomaviridae/genética
19.
JAMA ; 267(9): 1265, 1269-70, 1992 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-1538567
20.
JAMA ; 269(9): 1184, 1993 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-8433477
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA