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BACKGROUND: Thrombosis of an infra-inguinal bypass graft often results in a limb-threatening ischemia. There is no consensus on the optimal management strategy. AIM OF THE STUDY: To analyse safety and efficacy of catheter-guided intra-arterial thrombolysis to re-open thrombosed infra-inguinal bypass grafts and to identify factors that influence graft patency and limb salvage rate after thrombolytic procedures. METHODS: A continuous cohort-study of 106 thrombolytic procedures between 1993 to 2008. RESULTS: Despite a high initial success rate (76%), the mid-term results are less convincing, with a 58% re-occlusion rate at 45 months follow-up. Thrombosed vein grafts, old (2 weeks or more) occlusions, poor run-off and failure to identify or rectify an underlying causative stenosis are determinant for a poor long-term outcome of thrombolytic procedures. COMMENTS: The outcome results of author's experience are consistent with literature reports. Thrombolysis of occluded infra-inguinal bypass grafts should be limited to selective cases (recent occlusion, prosthetic or vein graft in place since 1 year or more, critical limb ischemia). Despite its obvious advantages, the long-term outcome of thrombolytic procedures is deceiving. The inherent risk of hemorrhagic complications should also be taken in account at the decision making of treatment strategy. The question whether, in general, catheter-guided selective intra-arterial thrombolysis offers a significant advantage over operative revascularisation (thrombectomy or new bypass) remains unanswered. A more selective approach seems to favour thrombolysis as most appropriate strategy in the management of recent (< 2 weeks) thromboses of grafts in place since at least 1 year.
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Oclusión de Injerto Vascular/tratamiento farmacológico , Terapia Trombolítica , Prótesis Vascular , Arteria Femoral , Fibrinolíticos/administración & dosificación , Humanos , Infusiones Intravenosas , Recuperación del Miembro , Arterias Tibiales , Resultado del Tratamiento , Grado de Desobstrucción VascularRESUMEN
The fate of oxo-polymers in nature is strongly dependent on environmental conditions, mainly on the intensity and duration of sunshine, which vary with the season and the climate. In this work, we report the effect of different scenarii on the production and the molecular composition of oligomers released from oxo-biodegradable HDPE films. Under our experimental conditions, the duration of accelerated weathering corresponded to a period of 3 months to 3 years of exposure to outside conditions under temperate climate. In addition, the oligomers were extracted in three different solvents: i) water to mimics the natural environment; ii) acetone and chloroform to identify oligomers trapped in the polymer matrix. The combination of high-resolution mass spectrometry and 1H NMR spectroscopy gives an extensive picture of the relative concentrations and the structural compositions of the extracted oligomers in the different tested conditions. In particular, the masses, the number of oxygen and carbon atoms could be determined for up to 2283 molecules. Globally the concentration and the size of oligomers increased with the duration of extraction, the level of aging of the polymer and the use of non-polar solvents. Surprisingly, the presence of highly oxidized molecules in acetone and chloroform extract, suggested an important swelling of HPDE films in these solvents and a better diffusion of these oligomers in the matrix. In nature, the biodegradability of oligomers could result from processes occurring both at the molecular (oxidation) and the macromolecular (diffusion and release) levels.
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Modelos Teóricos , Polietilenos/química , Solventes/química , Acetona/química , Biodegradación Ambiental , Cloroformo/química , Difusión , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Peso Molecular , Oxidación-Reducción , Factores de Tiempo , Agua/químicaRESUMEN
INTRODUCTION: Upper limb lymphedema occurs in 15 to 20% of patients after breast cancer treatment. Upper limb lymphedema without any history of neoplasia is an unusual situation. In this situation, breast cancer should be suspected. EXEGESIS: We reported two women, 53 and 67 years old, who developed upper limb lymphedema, 18 and 8 months before the diagnosis of breast cancer. In the two cases, clinical examination (breast and axillary palpation) was normal. In one case, mammography led to the diagnosis and in the other breast MRI was required to confirm the cancer. DISCUSSION: Upper limb lymphedema may be the presenting clinical feature of breast cancer. Breast cancer should be actively sought despite normal clinical and radiological findings. Breast MRI is required in this situation.
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Neoplasias de la Mama/diagnóstico , Linfedema/etiología , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Brazo , Vendajes , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/tratamiento farmacológico , Femenino , Humanos , Linfedema/terapia , Imagen por Resonancia Magnética , Mamografía , Persona de Mediana Edad , PalpaciónRESUMEN
The objective of this work was to develop a new approach to assess the specificity and the efficiency of biodegradation of oxidized oligomers extracted from aged HDPE polyethylene films and to bring insight on the mechanisms occurring during biodegradation. 1H NMR spectroscopy and LC Orbitrap™ mass spectrometry were combined together with data processing using Kendrick mass defect calculation and Van Krevelen Diagram. We showed that the molecular weight of extracted oligomers was lower than 850 Da with maximum chain length of 55 carbon atoms. The oligomers were divided into 11 classes of molecules with different oxidation state ranging from 0 to 10. All classes included series of chemically related compounds including up to 19 molecules. 95% of the soluble oligomers were assimilated by a strain of Rhodococcus rhodocchrous after 240 days of incubation. Large highly oxidized molecules completely disappeared while the other classes of molecules were still represented. Molecules containing 0-1 oxygen atom were less degraded. A strong shift to smaller molecules (<450 Da, 25 carbon atoms) was observed suggesting that longer molecules disappeared more rapidly than the smaller ones. It opens new perspectives on biodegradation processes as not only intracellular ß-oxidation must be considered but also extracellular mechanisms leading to chain cleavages.
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Biodegradación Ambiental , Polietileno/metabolismo , Rhodococcus/metabolismo , Carbono/metabolismo , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Oxidación-ReducciónRESUMEN
UNLABELLED: Skin leg ulcers are chronic painful wounds. The treatment of these ulcers is crucial for patients because pain has a significant impact on their daily lives. The analgesic effect of punch skin grafting (PSG) for the treatment of painful ulcers is not well described. The objective of the study is to assess the level of pain in patients with an ulcerated wound and to see if there is an analgesic effect of PSG. PATIENT AND METHODS: A single-center, non-interventional study conducted in hospitalized patients with one or several ulcer(s) of any type and which has been painful for more than six weeks. Pain was assessed before, the day after a PSG and then on the way out of hospital by a questionnaire and a numeric pain rating scale. Permanent pain and pain peaks were identified. RESULTS: Forty-one patients were included (23 men and 18 women) with a mean age of 73±21 years, 36% (n=15) with arterial ulcers, 36% (n=15) with venous ulcers, 12% (n=5) with necrotic angiodermatitis, 12% (n=5) with mixed ulcers and 4% (n=2) with "other ulcers" (due to infection and use of hydroxycarbamide). On day 1 of PSG, patients showed an improvement in terms of permanent pain (77%, n=24/31) and pain peaks (90%, n=37/41) respectively and 90% (n=28/31) and 95% (n=39/41) on the last day at hospital. Reduction in the use of strong opioids was found in 13 patients (81%). CONCLUSION: Punch skin grafting is a simple and validated treatment, which can reduce or eliminate pain related to ulcers. It has an effect on permanent pain and pain peaks. Its efficiency is particularly demonstrated on venous ulcers and mixed ulcers but also initially painful ulcers such as necrotic angiodermatitis or arterial ulcers.
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Úlcera de la Pierna/cirugía , Manejo del Dolor/métodos , Dolor , Trasplante de Piel/métodos , Anciano , Anciano de 80 o más Años , Analgesia , Arterias , Femenino , Hospitalización , Humanos , Úlcera de la Pierna/fisiopatología , Masculino , Persona de Mediana Edad , Úlcera Varicosa/fisiopatología , Úlcera Varicosa/cirugíaRESUMEN
INTRODUCTION: Skin leg ulcers are chronic painful wounds. The treatment of these ulcers is crucial for patients because pain has a significant impact on their daily lives. The analgesic effect of punch skin grafting (PSG) for the treatment of painful ulcers is not well described. The objective of the study is to assess the level of pain in patients with an ulcerated wound and to see if there is an analgesic effect of PSG. PATIENT AND METHODS: It was a single-center, non-interventional study conducted in hospitalized patients with one or several ulcer(s) of any type and which has been painful for more than six weeks. Pain was assessed before, the day after a PSG and then on the way out of hospital by a questionnaire and a numeric pain rating scale. Permanent pain and pain peaks were identified. RESULTS: Forty one patients were included (23 men and 18 women) with mean age of 73±21 years, 36% (n=15) with arterial ulcers, 36% (n=15) with venous ulcers, 12% (n=5) with necrotic angiodermatitis, 12% (n=5) with mixed ulcers and 4% (n=2) with "other ulcers" (due to infection and use of Hydroxycarbamide). On day 1 of PSG, patients showed an improvement in terms of permanent pain (77%, n=24/31) and pain peaks (90%, n=37/41) respectively and 90% (n=28/31) and 95% (n=39/41) on the last day at hospital. Reduction in the use of strong opioids was found in 13 patients (81%). CONCLUSION: Punch skin grafting is a simple and validated treatment, which can reduce or eliminate pain related to ulcers. It has an effect on permanent pain and pain peaks. Its efficacy is particularly demonstrated on venous ulcers and mixed ulcers but also initially painful ulcers such as necrotic angiodermatitis or arterial ulcers.
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Úlcera de la Pierna/cirugía , Dolor , Trasplante de Piel/métodos , Úlcera Varicosa/cirugía , Anciano , Anciano de 80 o más Años , Analgesia , Arterias , Femenino , Hospitalización , Humanos , Úlcera de la Pierna/fisiopatología , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Resultado del Tratamiento , Úlcera Varicosa/fisiopatologíaRESUMEN
OBJECTIVES: Determine whether general practitioners have sufficient expertise in the field of leg ulcers. METHOD: A cross-sectional survey was conducted among 179 general practitioners working in the region Île-de-France to evaluate the implementation of leg ulcer guidelines issued by the Superior Health Authority (HAS) in 2006. Participating physicians were either internship supervisors or practitioners in Paris' 14th district. RESULTS: The first hundred usable answers (response rate 65%) came from 71 internship supervisors and 29 practitioners of Paris' 14th district. Only 40% of the physicians were aware of the guidelines, with no significant difference noted between the two groups. 9/10 practitioners examined less than 10 patients with leg ulcers per year. Physical examinations were done according to the guidelines and a venous Doppler was prescribed in two thirds of the cases. The ankle-brachial pressure index (ABPI) essential to diagnose lower limb arteriopathy was measured for only 10% of the patients. In accordance with the guidelines, compression was by far (73%) considered as the main treatment as compared to dressing (37%), but compression therapy was well prescribed in only one-third of the cases. Despite poor prognosis criteria (characteristic and time course), referral for a specialized opinion was rare. CONCLUSION: Even if they were not always aware of the detailed guidelines, the practitioners applied the main recommendations. Nevertheless, practices could be improved by measuring the ABPI, searching for a diagnosis of arteriopathy, and better prescription of compression therapy. General practitioners should refer patients with leg ulcers to a specialized hospital unit.
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Médicos Generales , Hospitalización , Úlcera de la Pierna/terapia , Adulto , Anciano , Anciano de 80 o más Años , Índice Tobillo Braquial , Antibacterianos/uso terapéutico , Actitud del Personal de Salud , Terapia Combinada , Estudios Transversales , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Úlcera de la Pierna/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Estado Nutricional , Paris , Guías de Práctica Clínica como Asunto , Pautas de la Práctica en Medicina , Derivación y Consulta/estadística & datos numéricos , Trasplante de Piel/estadística & datos numéricos , Medias de Compresión , Encuestas y Cuestionarios , Ultrasonografía Doppler/estadística & datos numéricosRESUMEN
Mutant analysis represents one of the most reliable approaches to identifying genes involved in plant development. The screening of the Versailles collection of Arabidopsis thaliana T-DNA insertion transformants has allowed us to isolate different mutations affecting male gametophytic functions and viability. Among several mutated lines, five have been extensively studied at the genetic, molecular, and cytological levels. For each mutant, several generations of selfing and outcrossing have been carried out, leading to the conclusion that all these mutations are tagged and affect only the male gametophyte. However, only one out of the five mutations is completely penetrant. A variable number of T-DNA copies has integrated in the mutant lines, although all segregate at one mutated locus. Two mutants could be defined as "early mutants": the mutated genes are presumably expressed during pollen grain maturation and their alteration leads to the production of nonfunctional pollen grains. Two other mutants could be defined as "late mutant" since their pollen is able to germinate but pollen tube growth is highly disturbed. Screening for segregation ratio distortions followed by thorough genetic analysis proved to be a powerful tool for identifying gametophytic mutations of all phases of pollen development.
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Arabidopsis/genética , ADN/metabolismo , Mutación , Polen/genética , Polen/fisiología , Alelos , Southern Blotting , Modelos Genéticos , FenotipoRESUMEN
UNLABELLED: Negative BCR ABL myeloproliferative neoplasm (MPN) such as polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (MFP) are clonal hematological malignancies and may lead to a high risk of venous, arterial or microcirculatory thrombosis. Atypical sites of thrombosis can sometimes reveal the neoplasm disorder. Their diagnoses are a major issue because of the propensity to develop acute myeloid leukemia and/or myelofibrosis. The acquired JAK2V617F variant (Janus kinase 2; 9p24) is a prevalent MPN and also a sensitive marker for PV diagnosis (95% positive mutation), but not specific since found in approximately 50% of patients with ET and MFP. PATIENT AND METHODS: We present a diagnostic and a therapeutic approach based on one patient with microcirculatory ischemic manifestations in the toes, and who had strictly normal cell blood counts and was positive for JAK2V617F mutation: thrombotic risk factor evaluation; bone marrow biopsy; red cell adhesion assays. These experimental assays are promising for the development of new therapeutics in MPN; they assess red cell adherence to the vascular endothelium after the phosphorylation of Lu/BCAM subsequent to a positive JAK2V617F mutation. RESULTS: Compared with controls, our patient exhibited increased Lu/BCAM receptor phosphorylation and red blood cell adhesion. CONCLUSION: This development may lead to improved care for patients with thrombotic manifestations, normal blood cell counts, and a positive JAK2V617F mutation: multidisciplinary management, including regular hematological monitoring, could lead to the introduction of a cytoreductive treatment.
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Recuento de Células Sanguíneas , Moléculas de Adhesión Celular/metabolismo , Sistema del Grupo Sanguíneo Lutheran/metabolismo , Trastornos Mieloproliferativos/diagnóstico , Anciano , Médula Ósea/patología , Adhesión Celular , Comorbilidad , Diagnóstico Diferencial , Embolia por Colesterol/diagnóstico , Endotelio Vascular/patología , Eritrocitos/patología , Femenino , Francia/epidemiología , Humanos , Hidroxiurea/uso terapéutico , Isquemia/etiología , Janus Quinasa 2/genética , Janus Quinasa 2/metabolismo , Laminina/metabolismo , Masculino , Microcirculación , Mutación Missense , Trastornos Mieloproliferativos/complicaciones , Trastornos Mieloproliferativos/tratamiento farmacológico , Trastornos Mieloproliferativos/epidemiología , Trastornos Mieloproliferativos/genética , Fosforilación , Mutación Puntual , Procesamiento Proteico-Postraduccional , Factores de Riesgo , Fumar/efectos adversos , Trombofilia/etiología , Dedos del Pie/irrigación sanguíneaRESUMEN
In 1995 each of the Professional Councils at the Royal Victoria Hospital endorsed the creation of an Interdisciplinary Task Force on Conjugal Violence. Task force members were drawn from Medicine, Nursing and Social Work. The overall goal was to increase the quality of care that the interdisciplinary team could provide to their patients. This mandate encompassed three major tasks. First, to study the extent of awareness about the issue among health care professionals; second, to assess their needs for resources and education; and finally, to recommend and implement means of increasing the level of awareness of this health concern among professionals and patients. The task force members educated themselves about conjugal violence and developed a questionnaire that was distributed to health care professionals within the hospital. The number of individuals from each discipline who received the survey was proportionate to their actual number in the center and selected at random. Results of the survey indicated that all groups desired more information and education about the scope of the problem as well as means for assessing and intervening with patients who are abused. The task force developed a Conjugal Abuse Information Package, an Abuse Assessment Screen, a Public Awareness Program and an Ongoing Teaching Program for Health Care Professionals. This project provides an example of how an interdisciplinary health care team can successfully work together for the benefit of patients.
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Evaluación de Necesidades/organización & administración , Grupo de Atención al Paciente/organización & administración , Personal de Hospital/educación , Maltrato Conyugal/prevención & control , Actitud del Personal de Salud , Curriculum , Humanos , Personal de Hospital/psicología , Encuestas y Cuestionarios , VictoriaRESUMEN
OBJECTIVE: To evaluate compression therapy for venous leg ulcers in terms of adherence, acceptability, quality, and effectiveness. DESIGN OF STUDY: Prospective observational cohort study. SETTING: Vascular diseases outpatient clinic in Paris, France. SUBJECTS: One hundred consecutive patients with active or healed leg ulcers and chronic lower limb venous insufficiency stage C5 or C6 in the CEAP classification scheme. INTERVENTIONS: Compression systems applied in a community-based practice. MAIN OUTCOME MEASURES: A standardized form was used to collect: (1) data on patient adherence; (2) objective criteria evaluating the quality, effectiveness, and correct application of compression systems and; (3) patient education and perceptions about their compression therapy. RESULTS: Patient adherence with compression therapy was high (89%), even though it was often a source of discomfort. Only 10% of patients signaled no discomfort. Drawbacks reported by patients were excessive warmth (29%), pruritus (33%), unacceptably high cost (48%), and moderate to considerable difficulty putting on footwear (64%). In the 11% of patients who did not wear their compression system, reasons for nonadherence were inadequate comprehension of expected benefits (45.5%), pain related to compression (36.4%), difficulty applying the compression system (27.3%), and difficulty putting on footwear (27.3%). Application was correct in 51.7% of adherent patients; errors in the remaining patients included slippage, failure of the bandage to extend to just under the knee (55.8%), a tourniquet effect (21%), failure of bandaging starting at the base of the toes (37.2%), and failure to cover the heel (53.5%). Full edema control was achieved in 51.7% of adherent patients. Compression was adequate overall (worn, correctly applied, and effective) in 49% of adherent patients. The most common reasons for lack of effectiveness were inadequate pressure and errors in application. Lack of awareness of potential benefits and wearing modalities of compression therapy was noted in 56% of patients. CONCLUSION: Patients, nurses, and physicians have inadequate knowledge of the modalities of compression therapy and as a result they are not well respected. Educational programs are needed.
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Cooperación del Paciente/estadística & datos numéricos , Medias de Compresión , Úlcera Varicosa/terapia , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios ProspectivosAsunto(s)
Aciltransferasas/genética , Epistasis Genética , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente/genética , Proteínas Recombinantes de Fusión/biosíntesis , Aciltransferasas/biosíntesis , Caulimovirus/genética , Genes Virales , Modelos Genéticos , Fenotipo , Pigmentación/genética , Proteínas de Plantas/biosíntesis , Regiones Promotoras GenéticasRESUMEN
Traditionally, patients who received minor gynecology surgery remained in the hospital for a few days, during which time post-operative care was given by nurses. However, since patients are now often discharged the same day, the responsibility for this care has been transferred to the patients and their families. Because the nursing staff of the Gynecology Day Surgery Unit at the Royal Victoria Hospital believes there is a need for patient-monitoring after discharge and CLSCs do not offer services for this generally healthy clientele, they developed, with the head nurse and the assistant head nurse, a post-operative telephone follow-up program. This idea stemmed from the general need to adapt care as a result of the increase in day surgery. In addition to extending care beyond the hospital walls and improving its quality, this program has increased the job satisfaction of the nurses involved.
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Cuidados Posteriores , Procedimientos Quirúrgicos Ambulatorios/enfermería , Enfermedades de los Genitales Femeninos/cirugía , Teléfono , Continuidad de la Atención al Paciente , Femenino , Humanos , Calidad de la Atención de SaludRESUMEN
Transcription of a putative mitochondrial gene (orf138) has previously been correlated with Ogura cytoplasmic male-sterility (CMS) in rapeseed cybrids. In this paper, studies performed on a Brassica cybrid with a different organization of the orf138 locus confirm this association. We also show that mitochondria isolated from male-sterile rapeseed plants synthesize a polypeptide of 19 kDa, which is absent in fertile revertants. Antibodies against a glutathione S-transferase-ORF138 fusion protein were raised to establish that this 19 kDa polypeptide is the product of orf138. The anti-ORF138 serum was used to demonstrate that the orf138 translation product occurs only in sterile cybrids and co-purifies with the mitochondrial membrane fraction.
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Brassica/genética , ADN Mitocondrial/biosíntesis , Proteínas de la Membrana/biosíntesis , Proteínas de Plantas/biosíntesis , Plantas/genética , Western Blotting , Brassica/fisiología , Clonación Molecular , Desoxirribonucleasa BamHI , Desoxirribonucleasas de Localización Especificada Tipo II , Electroforesis en Gel de Poliacrilamida , Fertilidad/genética , Hibridación Genética , Membranas Intracelulares/química , Proteínas de la Membrana/genética , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Proteínas de Plantas/genética , Pruebas de Precipitina , Biosíntesis de Proteínas , Proteínas Recombinantes de Fusión/biosíntesis , Mapeo Restrictivo , Transcripción GenéticaRESUMEN
Sequence analysis of the Ogura-specific mitochondrial DNA (mtDNA) fragment isolated previously from Brassica cybrids carrying Ogura cytoplasmic male sterility (cms) revealed a tRNA(fMet) sequence, a putative 138 amino acid open reading frame (orf138), and a 158 amino acid ORF (orf158) previously observed in mitochondrial genomes from several other plant species. Transcription mapping showed that both ORFs are present on a 1.4 kb cms-specific transcript. The orf158 sequence is also transcribed in fertile plants on a different mRNA, and thus is unlikely to be related to cms. On the other hand, fertile revertant plants lack transcripts of the orf138 sequence, whose possible role in the mechanism of Ogura cms is discussed.
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Brassica/genética , ADN Mitocondrial/genética , ARN de Transferencia de Metionina , Transcripción Genética , Secuencia de Aminoácidos , Secuencia de Bases , Brassica/fisiología , Clonación Molecular , ADN Mitocondrial/aislamiento & purificación , Desoxirribonucleasas de Localización Especificada Tipo II , Fertilidad/genética , Genotipo , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , ARN/genética , ARN/aislamiento & purificación , ARN Mensajero/genética , Aminoacil-ARN de Transferencia/genética , Mapeo Restrictivo , Homología de Secuencia de AminoácidoRESUMEN
In higher plants, pollen tubes and root hairs share an ancient growth process named tip growth. We have isolated three allelic Arabidopsis mutant lines showing kinky-shaped pollen tubes and, when homozygous, showing shorter and thicker root hairs. The ultrastructure of pollen tubes in these kinky pollen (kip) mutants is similar to that of the wild type; however, time-lapse studies suggest that aberrant pollen tube shape is caused by periodic growth arrests alternated with phases of tube axis reorientation. The KIP gene encodes a protein of 2587 amino acids that is predicted to be targeted to the secretory pathway. KIP mRNA was detected in all organs investigated but was most abundant in pollen and roots. KIP has putative homologues in many eukaryotes, including mammals and yeast, and is similar to the Arabidopsis SABRE gene, whose mutation causes a dwarf phenotype. The phenotype of the kip/sab double mutant suggests related functions for both genes, however, the KIP protein is mostly required for tip-growth.
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Proteínas de Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/genética , Raíces de Plantas/crecimiento & desarrollo , Polen/crecimiento & desarrollo , Proteínas de Arabidopsis/metabolismo , Secuencia de Bases , Cartilla de ADN , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Prueba de Complementación Genética , Datos de Secuencia Molecular , Mutagénesis , Raíces de Plantas/genética , Polen/genética , Polen/ultraestructura , Reacción en Cadena de la Polimerasa , Transcripción GenéticaRESUMEN
Many genes are thought to be expressed during the haploid phase in plants, however, very few haploid-specific genes have been isolated so far. T-DNA insertion mutagenesis is a powerful tool for generating mutations that affect gametophyte viability and function, as disruption of a gene essential for these processes should lead to a defect in the transmission of the gametes. Mutants can therefore be screened on the basis of segregation distortion for a reporter resistance gene contained in the T-DNA. We have screened the Versailles collection of Arabidopsis transformants for 1:1 KanR:KanS segregation after selfing, focussing on gametophyte mutations which show normal transmission through one gametophyte and cause lethality or dysfunction of the other. Only 1.3% (207) of the 16,000 lines screened were scored as good candidates. Thorough genetic analysis of 38 putative T-DNA transmission defect lines (Ttd) identified 8 defective gametophyte mutants, which all showed 0 to 1% T-DNA transmission through the pollen. During the screen, we observed a high background of low-penetrance mutations, often affecting the function of both gametophytes, and many lines which were likely to carry chromosomal rearrangements. The reasons for the small number of retained lines (all male gametophytic) are discussed, as well as the finding that, for most of them, residual T-DNA transmission is obtained through the affected gametophyte.