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1.
Rheumatol Int ; 2024 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-38850323

RESUMO

Some emergency department (ED) visits by persons with rheumatoid arthritis (RA) may be avoidable. This study aims to describe ED use by persons with RA in Alberta, Canada over a 10-year period. Using linked population-based administrative datasets, the annual frequency of ED visits, timing of visits, acuity at presentation assessed (Canadian Triage Acuity Scale (CTAS)), return visits within 72 h, and final disposition were assessed. Most responsible diagnoses assessed by the ED provider were categorized. Between 2008 and 2017, a total of 48,633 persons with RA had 416,964 unique ED visits. There was a 41% relative increase in visits over the study period and within a fiscal year 37% of persons with RA on average attended an ED. Half of the visits were assessed as CTAS 4 'Less Urgent' (31%) and CTAS 5 'Non-Urgent' (19%). No specific diagnosis could be assigned in 36% of visits and RA was listed as the most responsible diagnosis in 2.5% of all visits. Hospital admissions, occurring on average for 14% of ED visits, increased by 15% over the 10 years, and were rare for CTAS 4 (6.4%) and CTAS 5 (1.4%) presentations. Male patients (difference to female 1.2%, 95%CI 0.6, 1.7) and urban patients (difference to rural 8.4%, 95%CI 7.7, 9.2) were more frequently admitted to hospital. Persons with RA have increased ED utilization over time, with a significant volume of less urgent and non-urgent visits. Opportunities for appropriate ambulatory care provision to reduce acute care use should be identified.

2.
AJP Rep ; 12(1): e10-e16, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35141030

RESUMO

Objective The objective of this study was to measure the impact of video education at the time of admission for delivery on intent and participation in skin-to-skin contact (SSC) immediately after birth. Methods This study was a randomized controlled trial of educational intervention in women ( N = 240) of 18 years or older admitted in anticipation of normal spontaneous term delivery. Alternate patients were randomized into video ( N = 120) and no video ( N = 120) groups. Both groups received a survey about SSC. The video group watched an educational DVD and completed a postsurvey about SSC. Results During the preintervention survey, 89.2% of those in the video group compared with 83.3% of those in the no video group indicated that they planned to use SSC ( p = 0.396). After the video, 98.3% planned to do SSC after delivery ( p < 0.001). However, only 59.8% started SSC within 5 minutes of delivery in the video group and only 49.4% started SSC within 5 minutes of delivery in the no video group ( p = 0.17). Conclusion Video education alters the intention and trends toward participation in SSC within 5 minutes of delivery. Despite the plans for SSC, however, there was no significant difference in rates between the two groups. These findings support that obstacles, other than prenatal education, may affect early SSC. Key Points Significant obstacles impact skin-to-skin rate.Video education alters skin-to-skin intent.Video education can improve skin-to-skin rate.Education can happen at the time of delivery.Video education can impact mothers and infants.

3.
J Vet Med Educ ; 49(4): 484-491, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34102093

RESUMO

Veterinary staff must be able to navigate end-of-life care with sensitivity and skill to create the best possible outcome for the patient, client, and veterinary team collectively. Despite the clear importance of euthanasia communication and procedural skills in veterinary practice, recent graduates of veterinary programs identified gaps between skills deemed important in clinical practice and skills emphasized in the curriculum. Little time is allocated to euthanasia procedural or communication training across the board in US veterinary programs. Thus, it is of paramount importance to establish intentional and well-designed instruction and assessment of euthanasia communication skills for veterinary trainees. A course on veterinary euthanasia communication skills was designed to emphasize themes and topics essential for a competent veterinarian. Through course evaluations, students expressed the sentiments that this course improved their euthanasia communication skills, that euthanasia communication skills are essential for their careers, and that the course content should be integrated into the core curriculum. This article presents a scaffold for the instruction and assessment of veterinary euthanasia communication skills in alignment with a competency-based veterinary education (CBVE) framework and outlines specific learning interventions used in the course that are scalable and may be extracted and incorporated into existing courses.


Assuntos
Educação em Veterinária , Médicos Veterinários , Animais , Comunicação , Currículo , Eutanásia Animal , Humanos
4.
Eur Rev Med Pharmacol Sci ; 21(7): 1645-1652, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28429340

RESUMO

OBJECTIVE: To evaluate the efficiency of pre-treatment in dyspermic males in IVF couples with a combination of micronutrients, for the purpose of improving the fertilization rate, the implantation rate and the outcome of the pregnancy. PATIENTS AND METHODS: This controlled prospective clinical study was performed in two medically assisted reproduction centers. 59 males with mild oligo-astheno-teratospermia (OAT) were admitted to the study. All of them had a history of previous in vitro fertilization (IVF) attempts with female partners aged < 40 diagnosed having tubal or idiopathic infertility. The subjects upon enrolment underwent a semen test and afterward were treated with alpha lipoic acid and glutathione (Fertiplus SOD®, Idi-Pharma, Catania, Italy) for 4 weeks (short-term). The primary endpoints that were evaluated are the following: fertilization rate (mean fertilization), implantation rate and pregnancy rate. RESULTS: At the end of this study all the males (mean age 39.5 ± 5.1) reported in not having any side effects during the administration of Fertiplus. Their female partners (mean age 34.9 ± 4.5) underwent IVF using the ICSI technique. The number of oocytes retrieved and inseminated was not statistically different in comparison to previous attempts, but with the same number of oocytes treated, the fertilization rate per couple demonstrated statistically significant increase (p<0.001). We did not observe a percentage increase in evolutionary embryos, but we noticed an improvement in embryo quality per individual couple (p<0.001), associated with a net increase in the implantation rate per couple (p<0.001) in terms of clinical pregnancy. The estimated miscarriage risk after treatment was five times lower (p<0.001). CONCLUSIONS: Short-term treatment with micronutrients in dyspermic subjects can improve the reproductive outcome of the IVF procedure.


Assuntos
Antioxidantes/administração & dosagem , Infertilidade Masculina/terapia , Micronutrientes/administração & dosagem , Injeções de Esperma Intracitoplásmicas , Transferência Embrionária , Feminino , Fertilização in vitro , Humanos , Itália , Masculino , Gravidez , Taxa de Gravidez , Estudos Prospectivos , Espermatozoides/efeitos dos fármacos
5.
Hum Reprod ; 12(3): 554-6, 1997 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9130758

RESUMO

The effect of cryopreservation on the integrity and fertilizing capacity of round spermatids was studied in two azoospermic patients. In December 1995 the patients, both with maturation arrest of spermatogenesis, were submitted to testicular sperm extraction (TESE) after an extensive examination of their ejaculate. Only round spermatids were found after testicular biopsy. Some of the spermatids were isolated and used for a first injection, while the remainder of the preparation was cryopreserved for successive cycles. Because of the failure of the first attempt, 3 months later, the same two patients were submitted to a second one. The frozen preparation was thawed and examined to evaluate the integrity and the viability of surviving round spermatids. More than 70% of the thawed spermatids were viable for injection. Fifteen oocytes at metaphase II, retrieved from the patients' wives, were microinjected with thawed round spermatids. Eighteen hours after the injection, seven out of 15 oocytes showed normal fertilization, with the presence of two pronuclei. The zygotes were cultured to observe embryonic development. After 48 h, six cleaving embryos had developed to at least the two-cell stage, while one had arrested at the pronuclear stage. At 72 h, the cleaving embryos showed further development to the four- to six-cell stage. They were then transferred into the uterus. After 3 weeks a clinical pregnancy was established in one patient [beta-human chorionic gonadotrophin (beta HCG) concentration was 2100 UI]. At 16 weeks of gestation, chromosomic analysis was performed, which confirmed the presence of a fetus with normal karyotype. The pregnancy is ongoing.


Assuntos
Criopreservação , Fertilização in vitro/métodos , Oócitos , Espermátides , Feminino , Humanos , Injeções , Masculino
6.
Hum Reprod ; 12(2): 286-91, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9070712

RESUMO

Between July 1995 and May 1996, 36 patients with non-obstructive azoospermia of secretory origin underwent intracytoplasmic injection of spermatids. A previous histological biopsy was performed on all patients: 15 had spermatogenic arrest, a further 13 had Sertoli cell-only syndrome, and the remaining eight had post-cryptorchidism tubal atrophy. The ejaculate was duly examined and a complete absence of spermatozoa and spermatids was confirmed, with only bacteria and debris being found. Testicular sperm extraction (TESE) was then performed. In 19 out of 36 cases round spermatids only were found, while elongated spermatids were found in the remaining 17. Both round and elongated spermatids were isolated and used for injection. A total of 135 oocytes at metaphase II were recovered from 19 partners and injected with round spermatids, while 123 mature oocytes from 17 partners were injected with elongated spermatids. The number of oocytes fertilized, as judged by the presence of two pronuclei, was 75 (55.5%) and 71 (57.7%) respectively. By 34 h after injection, the number of embryos which had cleaved to the 2-cell stage was 56 (74.6%) with round spermatids and 55 (77.4%) with elongated spermatids. All cleaved embryos were transferred into the uterus of the partners. Clinical pregnancies were established in two cases of round spermatid cycles (10.5%) (both are still ongoing), and three cases of elongated spermatid cycles (17.6%) (two are still ongoing; one was lost after 8 weeks of gestation). Chromosomal analysis showed that all fetuses had a normal karyotype (three male and one female) with no chromosomal abnormalities.


Assuntos
Fertilização in vitro/métodos , Oligospermia , Espermátides , Feminino , Humanos , Masculino , Gravidez , Resultado da Gravidez
7.
Hum Reprod ; 11(11): 2488-92, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8981141

RESUMO

The aim of this study was to examine the safety and the efficiency of a 'non-contact' UV laser to assist hatching through zona opening of human embryos. Between January and November 1995 we performed zona drilling for assisted hatching using a new laser system (PALM UV Laser microbeam), operating in a 'non-contact' mode to create a hole in the zona pellucida of human embryos. In a randomized study, laser zona opening was applied on embryos from two groups of patients with repeated in-vitro fertilization (IVF) failures (two to four attempts): group A was composed of 107 patients who received mixed embryos (216 laser-treated and 223 not treated) and group B of 72 patients who received 218 laser-treated embryos only. Both groups were compared with a control group of 98 patients whose embryos were not laser treated (n = 407) (group C). The mean ages of all groups (38.1, 38.2 and 37.8 years respectively) and the number of IVF attempts (two to four attempts) were similar. The resulting clinical pregnancies were 39 (36.4%) in group A, 32 (44.4%) in group B and 19 (19.3%) in group C. The implantation rates/embryo were 9.3% in A, 16% in B and 5.1% in the control group. In total, 17 normal babies have been delivered (10 in group A and seven in group B). These results show that laser zona drilling increased the pregnancy and implantation rates in all the treated patients. The increase was slight but significant in patients of group A (P < 0.01 and P < 0.02), it was even higher in the patients of group B (P < 0.05).


Assuntos
Implantação do Embrião/fisiologia , Embrião de Mamíferos/ultraestrutura , Lasers , Técnicas Reprodutivas , Raios Ultravioleta , Zona Pelúcida/fisiologia , Feminino , Humanos , Gravidez
8.
Hum Reprod ; 11(3): 590-4, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8671273

RESUMO

From 1993 to 1994, in our centre, laser-assisted hatching was performed on 2- to 4-cell stage embryos obtained from in-vitro fertilization (IVF) patients. We treated 376 embryos from 96 patients with repeated IVF failures (two to four attempts) (group A) and 397 embryos from 111 patients undergoing IVF for the first time (group B). Embryos were transferred immediately after the laser treatment. Both groups were compared to control groups (A' and B') whose embryos were transferred with intact zona pellucida (ZP). The resulting clinical pregnancies were 41 in A and 44 in B versus 24 in A' and 23 in B' respectively. The pregnancy rates per patient were 42.7 and 39.6% versus 23.1 and 19% in the control groups (P < or = 0.05), while the implantation rates per embryo were 12.2% in A and 11.8% in B versus 7.3% and 7.1%. These results show that laser zona thinning of human embryos at 48 h after egg retrieval significantly increases the implantation and pregnancy rate (P < or = 0.05).


Assuntos
Fertilização in vitro/métodos , Terapia a Laser , Zona Pelúcida/efeitos da radiação , Adulto , Implantação do Embrião , Transferência Embrionária/métodos , Feminino , Humanos , Gravidez , Resultado da Gravidez , Técnicas Reprodutivas
10.
Med Pregl ; 44(7-8): 310-2, 1991.
Artigo em Servo-Croata (Latino) | MEDLINE | ID: mdl-1806773

RESUMO

The authors present two cases of arrhythmogenic right ventricular dysplasia in two young males, who had died by sudden death. A brief presentation is given of the clinical manifestation, uninvasive and invasive diagnostic possibilities, of the pathoanatomic finding and the pathohistological presentation, and the possibilities of treatment.


Assuntos
Morte Súbita Cardíaca/etiologia , Ventrículos do Coração/anormalidades , Adolescente , Arritmias Cardíacas/etiologia , Humanos , Masculino
11.
J Leukoc Biol ; 48(6): 502-11, 1990 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2121885

RESUMO

Bovine alveolar macrophage metabolism of arachidonic acid (AA) via cyclooxygenase (CO) and lipoxygenase (LO) pathways is stimulus specific. Under standard conditions with RPMI-1640 media containing 0.4 mM Ca2+, the calcium ionophore A23187 stimulates the release of both CO and LO products, whereas opsonized zymosan and phorbol myristate acetate (PMA) selectively stimulate the CO pathway in these cells. We have examined the effect of varying the extracellular concentration of calcium (0-2.4 mM) on the profiles of AA metabolites secreted with differing stimuli. All stimuli caused the release of CO products, even in the absence of calcium in the media. The magnitude of release was correlated with increasing extracellular calcium concentrations, indicating some dependence of phospholipase activation on extracellular calcium. However, there were notable differences between stimuli regarding the magnitude of CO product formation and dependence on extracellular Ca2+. No 5-LO products were demonstrable with either zymosan or PMA at any concentration of extracellular calcium tested, and inhibition of CO by indomethacin did not result in 5-LO product formation for these stimuli. The production of 5-LO products in bovine alveolar macrophages by A23187 required extracellular calcium, demonstrating an absolute dependence for activation of the 5-LO pathway on an influx of extracellular calcium. Our results indicate that intracellular and extracellular Ca2+ have differing roles in the metabolism of AA down CO and LO pathways in bovine alveolar macrophages depending on the stimulus used. This regulation suggests that the pools of calcium required for activation of phospholipase A2 (PLA2) are not necessarily available for the 5-LO enzyme.


Assuntos
Ácidos Araquidônicos/metabolismo , Cálcio/farmacologia , Macrófagos/metabolismo , Animais , Ácido Araquidônico , Calcimicina/farmacologia , Bovinos , Ácido Egtázico/farmacologia , Indometacina/farmacologia , Fosfolipases A/fisiologia , Fosfolipases A2 , Alvéolos Pulmonares/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Zimosan/farmacologia
12.
Mol Cell Biol ; 6(3): 925-32, 1986 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3022139

RESUMO

A 9-kilobase pair CEN4 linear minichromosome constructed in vitro transformed Saccharomyces cerevisiae with high frequency but duplicated or segregated inefficiently in most cells. Stable transformants were only produced by events which fundamentally altered the structure of the minichromosome: elimination of telomeres, alteration of the centromere, or an increase of fivefold or greater in its size. Half of the stable transformants arose via homologous recombination between an intact chromosome IV and the CEN4 minichromosome. This event generated a new chromosome from each arm of chromosome IV. The other "arm" of each new chromosome was identical to one "arm" of the unstable minichromosome. Unlike natural yeast chromosomes, these new chromosomes were telocentric: their centromeres were either 3.9 or 5.4 kilobases from one end of the chromosome. The mitotic stability of the telocentric chromosome derived from the right arm of chromosome IV was determined by a visual assay and found to be comparable to that of natural yeast chromosomes. Both new chromosomes duplicated, paired, and segregated properly in meiosis. Moreover, their structure, as deduced from mobilities in orthogonal field gels, did not change with continued mitotic growth or after passage through meiosis, indicating that they did not give rise to isochromosomes or suffer large deletions or additions. Thus, in S. cerevisiae the close spacing of centromeres and telomeres on a DNA molecule of chromosomal size does not markedly alter the efficiency with which it is maintained. Taken together these data suggest that there is a size threshold below which stable propagation of linear chromosomes is no longer possible.


Assuntos
Cromossomos/ultraestrutura , Saccharomyces cerevisiae/genética , Composição de Bases , Enzimas de Restrição do DNA , Meiose , Peso Molecular , Plasmídeos , Saccharomyces cerevisiae/citologia , Transformação Genética
13.
Biochemistry ; 24(24): 6988-97, 1985 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-4074735

RESUMO

The binding of a steroid receptor to specific nuclear sites (i.e., nuclear acceptor sites) represents the immediate event preceding the steroid regulation of gene transcription. How the same steroid receptor regulates different genes in different tissues is unknown. Since a major fraction of the nuclear acceptor sites for a variety of steroid receptors has been reported to be masked in the chromatins of a variety of tissues, the differential expression of the nuclear acceptor sites may explain this regulation of different genes. In the avian oviduct, the removal of a subfraction of chromosomal non-histone proteins, termed CP-2, results in the unmasking of the nuclear acceptor sites for the progesterone receptor (PR). Further, the extent of masking of these nuclear acceptor sites for PR has been reported to vary during cytodifferentiation of the avian oviduct. This paper describes a method for the reconstitution of the masking of PR nuclear acceptor sites in the avian oviduct chromatin using a partially purified chromosomal protein fraction (CP-2b). The reannealling of the CP-2b fraction to unmasked avian oviduct chromatin (termed nucleoacidic protein or NAP) results in the "remasking" of about the same number of nuclear acceptor sites for PR as found in intact chromatin. Because some of the PR acceptor sites on the NAP cannot be remasked, these sites either must be protected from masking or not be recognized by the masking proteins. The masking activity apparently involves only protein(s) because the unmasking of acceptor sites can be achieved with protease but not ribonuclease activities and because the dissociated masking activity is destroyed only by proteases. The masking appears to be reversible because the reconstituted masked sites can again be unmasked. Preliminary purification and characterization of the masking activity in fraction CP-2b by molecular sieve chromatography indicate a heterogeneity of size with the activity eluting in a molecular weight range of from 60 000 to greater than 150 000. Whether the masking proteins prevent the binding of the progesterone receptor by directly binding the acceptor sites or by binding neighboring domains to condense the chromatin is unknown. It is speculated that the masking of acceptor sites may be responsible in part for determining the tissue-specific gene expression induced by steroids and/or may play a role in the unresponsiveness of certain human tumors containing steroid receptors.


Assuntos
Núcleo Celular/metabolismo , Cromatina/metabolismo , Nucleoproteínas/fisiologia , Oviductos/metabolismo , Receptores de Progesterona/metabolismo , Animais , Galinhas , Cromatina/isolamento & purificação , Feminino , Cinética , Peso Molecular , Receptores de Progesterona/isolamento & purificação
14.
Curr Genet ; 9(6): 441-5, 1985.
Artigo em Inglês | MEDLINE | ID: mdl-3916729

RESUMO

Natural termini from macronuclear DNA of the ciliated protozoans Tetrahymena thermophila and Oxytricha fallax can support telomere formation yeast. However, plasmids carrying these ciliate termini are modified by the addition of DNA which hybridizes to the synthetic oligonucleotide poly [d(C-A]), a sequence which also hybridizes to terminal restriction fragments from yeast chromosomes but not to Tetrahymena or Oxytricha macronuclear DNAs. Thus, in yeast, the creation of new telomeres on ciliate termini involves the acquisition of yeast-specific terminal sequences presumably by either recombination or non-templated DNA synthesis. The RAD52 gene is required for the majority of yeast mitotic and meiotic recombination events. Moreover, the absence of an active RAD52 gene product results in high rates of chromosome loss. Here we demonstrate that terminal restriction fragments from Tetrahymena macronuclear ribosomal DNA (rDNA) support the formation of modified telomeres in a yeast strain carrying a defect in the RAD52 gene. Moreover, linear plasmids bearing these modified ciliate termini are stably propagated in rad52- cells.


Assuntos
Mutação , Plasmídeos , Recombinação Genética , Saccharomyces cerevisiae/genética , Animais , Eucariotos/genética , Tetrahymena/genética
15.
Proc Natl Acad Sci U S A ; 81(5): 1475-9, 1984 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-6324194

RESUMO

The termini of macronuclear DNA molecules from the protozoan Oxytricha fallax share a common sequence and structure, both of which differ markedly from those deduced for yeast telomeres. Despite these differences, terminal restriction fragments from O. fallax macronuclear DNA can support telomere formation in yeasts. Two linear plasmids (LYX-1 and LYX-2) constructed by ligating BamHI-digested total Oxytricha macronuclear DNA to a yeast vector were analyzed. One end of LYX-1 and both ends of LYX-2 are derived from the Oxytricha DNA that encodes rRNA (rDNA) whereas the other end of LYX-1 is from an Oxytricha fragment other than rDNA. After propagation in yeast, both ends of LYX-1 and LYX-2 retain the C4A4 repeat characteristic of the O. fallax terminal sequence. In addition, both ends of both plasmids acquire 300-1000 base pairs of DNA containing the sequence (C-A)n, a sequence found near the termini of yeast chromosomes. Thus, at least two different Oxytricha termini display distinctive properties in yeast cells in that linear plasmids containing them are not degraded nor are they integrated into chromosomal DNA. These Oxytricha termini may act directly as telomeres in yeast; alternatively, the Oxytricha DNA may serve as a signal that results in the elaboration of a yeast telomere on the ciliate DNA.


Assuntos
DNA Fúngico/genética , DNA/genética , Eucariotos/genética , Saccharomyces cerevisiae/genética , Animais , Composição de Bases , Sequência de Bases , DNA Ribossômico , Vetores Genéticos , Hibridização de Ácido Nucleico , Plasmídeos , Especificidade da Espécie
16.
J Biol Chem ; 259(4): 2411-21, 1984 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-6698973

RESUMO

The progesterone receptors from various stages of estrogen induced oviduct development, estrogen withdrawal, and secondary stimulation with estrogen were examined. The progesterone receptors were characterized for their biological function (i.e. capacity for nuclear translocation, nuclear binding, and effects on RNA polymerase II activity) as well as certain physical properties. The progesterone receptors from the undeveloped or partially developed oviducts (0 to 8 days of estrogen treatment) displayed little or no nuclear translocation and binding in vivo or in vitro. Similarly, progesterone showed little or no effect in vivo on RNA polymerase II activity at the early stages of development. As development progressed from 8 to 12 days of estrogen treatment, the above parameters rapidly increased to maximal levels and plateaued through day 23 of estrogen treatment. A marked decrease in these parameters occurred within 1 day of estrogen withdrawal. The reverse series of events occurred during secondary estrogen stimulation of 10-day-old withdrawn chicks. While the receptor concentrations increased rapidly to maximum values by 2 days of restimulation, receptor function did not return until day 4. Similarly, the effects of progesterone on RNA polymerase II activity reached maximal values by day 4. The progesterone receptor isolated from oviducts during development, estrogen withdrawal, and restimulation, displayed similar patterns of cell-free binding to chromatin and nucleoacidic protein as that observed in vivo supporting the nativeness of the in vitro binding assay. In contrast, the cell-free binding of these same progesterone receptor to pure DNA were not similar to the in vivo binding, i.e. no patterns (differences) in progesterone receptor binding were observed. These data support that protein DNA complexes and not pure DNA represent the native acceptor sites for oviduct progesterone receptor. Comparison of the progesterone receptor between the functional and nonfunctional states revealed no differences in the steroid affinity for the receptor, in the apparent pI of the species, or in the sedimentation of the receptor under high salt conditions. However, the nonfunctional receptors consistently displayed a deficiency in one of the two monomer molecular species (the B species) as determined by isoelectric focusing. These results suggest that both monomer species of progesterone receptor are required for biological activity. Interestingly, the 7S "aggregate" species of the progesterone receptor was constantly detected even when only one of the monomer species was present.(ABSTRACT TRUNCATED AT 400 WORDS)


Assuntos
Núcleo Celular/metabolismo , Dietilestilbestrol/farmacologia , Estradiol/farmacologia , Oviductos/metabolismo , Progesterona/farmacologia , Receptores de Progesterona/genética , Envelhecimento , Animais , Galinhas , Feminino , Oviductos/efeitos dos fármacos , Oviductos/crescimento & desenvolvimento , RNA Polimerase II/metabolismo , Receptores de Progesterona/efeitos dos fármacos , Receptores de Progesterona/metabolismo
18.
Proc Natl Acad Sci U S A ; 80(11): 3406-10, 1983 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-6344082

RESUMO

Circular recombinant DNA plasmids that contain autonomously replicating sequences (ARSs) are maintained in extrachromosomal form in transformed yeast cells. However, these plasmids are unstable, being rapidly lost from cells growing without selection. Although the stability of such a plasmid can be increased by the presence of yeast centromere DNA (CEN), even CEN plasmids are lost at a high rate compared to a bona fide yeast chromosome. Natural yeast chromosomes are linear molecules; therefore, we have asked if linearization can improve the stability of recombinant DNA plasmids. Linear plasmids with and without yeast CENs were constructed in vitro by using termini from the extrachromosomal ribosomal DNA (rDNA) of the ciliated protozoan Tetrahymena thermophila as "telomeres." These linear plasmids transformed yeast at high frequency and were maintained as linear extrachromosomal molecules during mitotic growth. Moreover, linear plasmids containing CENs were also transmitted through meiosis: these plasmids segregate predominantly 2+:2- at the first meiotic division, indicating that Tetrahymena rDNA termini can provide telomere function during yeast meiosis. Linear plasmids without CENs were about as stable in mitosis as the comparable circular plasmid. Thus, the Tetrahymena rDNA termini have no marked positive or negative effect on the mitotic stability of ARS plasmids. However, linear plasmids containing CENs are three to four times less stable in mitotic cells than circular CEN plasmids. This decrease in stability is not due to a functional change in the centromere itself; rather, linearization of a CEN plasmid has a direct detrimental effect on its mitotic stability. These results may reflect the existence of spatial constraints on the positions of centromeres and telomeres, constraints which must be satisfied to achieve stable segregation of chromosomes during mitosis.


Assuntos
Meiose , Mitose , Plasmídeos , Saccharomyces cerevisiae/genética , Animais , Sequência de Bases , Replicação do DNA , DNA Fúngico/genética , DNA Recombinante/metabolismo , Tetrahymena/genética
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