RESUMEN
Noonan syndrome is associated with complex lymphatic abnormalities. We report dynamic-contrast enhanced MR lymphangiography (DCMRL) findings in children and adults with Noonan syndrome to further elucidate this complex disease spectrum. A retrospective evaluation of patients with confirmed Noonan syndrome and clinical signs of lymphatic dysfunction undergoing DCMRL between 01/2019 and 04/2021 was performed. MRL included T2-weighted imaging (T2w) and DCMRL. Clinical history/presentation and genetic variants were recorded. T2w-imaging was evaluated for central lymphatic abnormalities and edema distribution. DCMRL was evaluated regarding the presence of cisterna chyli/thoracic duct, lymphatic leakages, pathological lymphatic reflux and abnormal lymphatic perfusion. The time from start of contrast-injection to initial enhancement of the thoracic duct venous junction was measured to calculate the speed of contrast propagation. Eleven patients with Noonan syndrome with lymphatic abnormalities (5 female, 6 male; 7 infants, 4 adults; mean age 10.8 ± 16.4 years) were identified (PTPN11 n = 5/11 [45.5%], RIT1 n = 5/11 [45.5%], KRAS n = 1/11 [9%]). Patients had a chylothorax (n = 10/11 [91%]) and/or pulmonary lymphangiectasia [dilated pulmonary lymph vessels] (n = 9/11 [82%]). Mediastinal/pulmonary edema was depicted in 9/11 (82%) patients. The thoracic duct (TD) was (partially) absent in 10/11 (91%) cases. DCMRL showed lymphatic reflux into intercostal (n = 11/11 [100%]), mediastinal (n = 9/11 [82%]), peribronchial (n = 8/11 [73%]), peripheral (n = 5/11 [45.5%]) and genital lymphatics (n = 4/11 [36%]). Abnormal pulmonary/pleural lymphatic perfusion was seen in 8/11 patients (73%). At infancy peripheral/genital edema was more prevalent in patients with RIT1 than PTPN11 (n = 3/5 vs. n = 0/5). Compared to patients with PTPN11 who had fast lymphatic enhancement in 4/5 patients, enhancement took markedly longer in 4/5 patients with RIT1-mutations. Thoracic duct dysplasia, intercostal reflux and pulmonary/pleural lymphatic perfusion are characteristic findings in patients with Noonan syndrome presenting with chylothorax and/or pulmonary lymphangiectasia. Central lymphatic flow abnormalities show possible phenotypical differences between PTPN11 and RIT1-mutations.
Asunto(s)
Quilotórax , Anomalías Linfáticas , Síndrome de Noonan , Adolescente , Adulto , Niño , Quilotórax/diagnóstico por imagen , Femenino , Humanos , Lactante , Anomalías Linfáticas/complicaciones , Anomalías Linfáticas/diagnóstico por imagen , Anomalías Linfáticas/genética , Linfografía/métodos , Masculino , Síndrome de Noonan/diagnóstico por imagen , Síndrome de Noonan/genética , Estudios Retrospectivos , Adulto JovenRESUMEN
The aim of the study was to assess injection needle positioning for contrast-enhanced MR-lymphangiography (MRL) by ultrasound-guided injection of saline-solution. 80 patients (33 male, mean age 43.1 years) were referred for MRL. The injection needle position was assessed by injection of saline-solution. Consecutive lymph node distension was observed on sonography followed by MRL. Transpedal MRL was performed when no inguinal lymph nodes could be identified. The inguinal lymph node detection rate was recorded. MR-lymphangiograms were assessed regarding primary (i.e. enhancement of draining lymph vessels) and secondary technical success (i.e. lymph vessel enhancement after repositioning of the needle). MRL was considered as clinically successful if enhancement of the central lymphatic system and/or a lymphatic pathologies were observed. For a total of 92 MRLs 177 groins were evaluated sonographically. In 171/177 groins (96.6%) lymph nodes were identified. After needle placement lymph node distension was observed in 171/171 cases (100%) on saline injection. MR-contrast injection demonstrated enhancement of draining lymph vessels in 163/171 cases (95.3%). In 6/171 cases (3.5%) in-bore needle retraction lead to lymphatic enhancement. In one patient [2/171 nodes (1.1%)] no lymphatic enhancement was seen despite repeated needle repositioning. Overall contrast application was technically successful in 169/171 cases (98.8%). In the 6 groins in which no nodes were identifiable, transpedal MRL was successful. So overall 91/92 MRLs (98.9%) were clinically successful. No complications were recorded. Confirmation of the needle position for nodal MRL by sonographically controlled saline injection is a reliable technique with a high success rate of MRL.
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Medios de Contraste , Linfografía , Adulto , Humanos , Ganglios Linfáticos/diagnóstico por imagen , Ganglios Linfáticos/patología , Sistema Linfático/patología , Linfografía/métodos , Imagen por Resonancia Magnética/métodos , Masculino , Ultrasonografía , Ultrasonografía IntervencionalRESUMEN
Modern patient-centered and cost-efficient care concepts in hospitals require the mapping of multidisciplinary process chains into clinical pathways. Clinical decision support systems and operations research methods use algorithms to classify patients into homogeneous groups and to model a complete clinical pathway for scheduling individual procedures. An improvement of the economic situation of the care facility can be achieved through improved resource utilization, reduced patient waiting times and a shortening of the length of stay. The interdisciplinary use of centrally stored interoperable information and comprehensive care management via information technology (IT) services lay the foundation for the dissolution of traditional IT system architectures in medicine and the development of flexibly integrable modern system platforms. New IT approaches such as the semantically standardized definition of procedures and resource properties, the use of clinical decision support systems and the use of service-oriented system architectures form the basis for the deep integration of radiology services into comprehensive interdisciplinary care concepts.
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Sistemas de Apoyo a Decisiones Clínicas , Prestación Integrada de Atención de Salud , Radiología , Algoritmos , HumanosRESUMEN
BACKGROUND: Creating the neovaginal canal in transwomen is one of the most delicate steps of Genital Gender Affirming Surgery (GGAS). Injury to the rectum is a rare but serious complication that can lead to further surgery and even creation of a colostomy. AIM: Implementation of a novel hydrospacing technique (HST) based on transrectal ultrasound (TRUS)-guided hydrodistension. METHODS: Between June 2018 and June 2020 54 transwomen received GGAS with HST. Immediately before GGAS transperineal hydrodistension was performed using a TSK-Supra-Needle (20 Gauge, 120 mm length), that was placed under direct TRUS-guided visual control between Denonvilliers' fascia and the anterior rectal wall. 40 - 60 ml normal saline were administered perineally to separate Denonvilliers' fascia from the anterior rectal wall to create a dissection of at least 20 mm. For better intraoperative visualization the hydrodissected space was also dyed using 2ml of methylenblue while retracting the needle. A retrospectively analysed, clinically and demographically comparable series of 84 transwomen who underwent GGAS between June 2016 and June 2018 served as control group. All 138 surgeries were performed by the same experienced surgeon. OUTCOMES: The effect of the novel hydrospacing technique on neovaginal dimensions and operating time. RESULTS: Patients in both groups did not differ in baseline patient characteristics such as age and body mass index (HST 35 vs 38 years in control group, P = .44 and body mass index 26 vs 25 kg/m2, P = .73). Vaginal depth and width were significantly larger in the HST subgroup as compared to controls (14.4 cm vs 13.5 cm, P = .01 and 4.2 cm vs 3.8 cm, P < .001). No statistically significant difference occurred in intraoperative rectal injury (n = 0 in HST group, n = 2 in control group, P = .26). Median total OR-time was comparable for GGAS including HST before vaginoplasty to standard technique (211 minutes for HST vs 218 minutes; P = 0.19). CLINICAL IMPLICATIONS: The proposed additional surgical step during GGAS is minimally invasive and safe, simplifies GGAS and potentially helps to avoid complications such as rectal injury. STRENGTH & LIMITATIONS: Single-surgeon series, limited follow-up time and no prospective randomization. CONCLUSION: HST is a safe and feasible procedure, which facilitates a safe preparation of the neovaginal canal during male to female GGAS. Panic A, Rahmani N, Kaspar C, et al. Transrectal Ultrasound Guided Hydrodistension - A New Surgical Way in Transgender Surgery. J Sex Med 2021;18:1135-1141.
Asunto(s)
Cirugía de Reasignación de Sexo , Personas Transgénero , Transexualidad , Femenino , Humanos , Masculino , Estudios Retrospectivos , Ultrasonografía IntervencionalRESUMEN
The insertion of a penile prosthesis (PP) is a definitive treatment option for erectile dysfunction (ED), induratio penis plastica, after phalloplasty or priapism. The aim is a "normal" erection with the possibility of a satisfactory sexual life. The costs of the operation are covered by the health insurance. In addition, manual dexterity, concomitant diseases and possible contraindications should be considered preoperatively. While semirigid PPs are simply aligned in the desired position when used, inflatable PPs must be activated and deactivated via a pump. In addition to injury to local structures and postoperative infections, long-term complications such as mechanical implant failure or an undesirable cosmetic result may also occur. Careful patient selection and a detailed counselling and information session are therefore of decisive importance. Implantation is performed in the supine or lithotomy position via an infrapubic or penoscrotal approach. PPs should not be implanted if cutaneous, systemic or urinary tract infections are present. Inflatable PPs are preferred by most patients as they come closest to a "natural" erection. A PP offers one of the highest satisfaction rates among treatment options, regardless of indication, and is highly rated by patients and their partners across models due to product reliability. Differences between the models of the various manufacturers could not be demonstrated. The choice of prosthesis should therefore be adapted to the patient's individual requirements and health conditions.
Asunto(s)
Disfunción Eréctil , Implantación de Pene , Prótesis de Pene , Disfunción Eréctil/cirugía , Humanos , Masculino , Satisfacción del Paciente , Erección Peniana , Pene/cirugía , Diseño de Prótesis , Reproducibilidad de los ResultadosRESUMEN
Male-to-Female (MtF) gender affirmation surgery (GAS) comprises the creation of a functional and aesthetic perineogenital complex. This study aimed to evaluate the effect of GAS on sexuality. We retrospectively surveyed all 254 MtF transsexual patients who had undergone GAS with penile inversion vaginoplasty at the Department of Urology, University Hospital Essen, Germany, between 2004 and 2010. In total, we received 119 completed questionnaires after a median of 5.05 years since surgery. Of the study participants, 33.7% reported a heterosexual, 37.6% a lesbian, and 22.8% a bisexual orientation related to the self-perceived gender. Of those who had sexual intercourse, 55.8% rated their orgasms to be more intensive than before, with 20.8% who felt no difference. Most patients were satisfied with the sensitivity of the neoclitoris (73.9%) and with the depth of the neovaginal canal (67.1%). The self-estimated pleasure of sexual activity correlated significantly with neoclitoral sensitivity but not with neovaginal depth. There was a significant correlation between the ease with which patients were able to become sexually aroused and their ability to achieve orgasms. In conclusion, orgasms after surgery were experienced more intensely than before in the majority of women in our cohort and neoclitoral sensitivity seems to contribute to enjoyment of sexual activity to a greater extent than neovaginal depth.
Asunto(s)
Cirugía de Reasignación de Sexo , Sexualidad , Adulto , Bisexualidad , Femenino , Humanos , Masculino , Estudios Retrospectivos , Conducta SexualRESUMEN
BACKGROUND: Gender reassignment surgery (GRS) can lead to discrimination. This transition makes great demands on the individual and also affects the social environment. OBJECTIVES: To evaluate the social support of male-to-female (MtF) transgender people. MATERIALS AND METHODS: Group A comprised 254 consecutive MtF transsexuals, who received a penile inversion vaginoplasty between 2004 and 2010. These women were surveyed retrospectively. Group B comprised 144 consecutive MtF transsexuals who presented for preoperative counselling. These patients were asked to answer the survey in advance of the planned GRS. RESULTS: The return rate was 46.9 % (A) and 95.1 % (B). In both groups, approximately two-thirds lived with their parents or children at ease. About 13.4 % (A) and 16.9 % (B) estimated the relationship towards their parents and one- seventh (A) or one-sixth (B) woman rated their relationship towards their children as poor. The acceptance of the parents regarding GRS was 65.6 % (A) and 77.1 % (B). In total 20 % (A) and 9.2 % (B) did not, however, accept GRS in their children. The acceptance of children regarding GRS was 64.9 % (A) and 71.1 % (B) with 10.8 % (A) and 6.7 % (B) who did not approve the decision. DISCUSSION: Social support is an important resource in the context of gender reassignment surgery. Understanding can help to improve the situation for transsexuals and to reduce consecutive healthcare utilisation.
Asunto(s)
Procedimientos de Reasignación de Sexo/psicología , Procedimientos de Reasignación de Sexo/estadística & datos numéricos , Sexismo/psicología , Sexismo/estadística & datos numéricos , Apoyo Social , Personas Transgénero/psicología , Personas Transgénero/estadística & datos numéricos , Adolescente , Adulto , Distribución por Edad , Anciano , Niño , Femenino , Alemania/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Distribución por Sexo , Sexismo/prevención & control , Encuestas y Cuestionarios , Adulto JovenRESUMEN
The "plasticity hypothesis" proposes that major depression is caused by morphological and biochemical modifications in neurons and astrocytes and those beneficial pharmacological effects of selective-serotonin-reuptake-inhibitors (SSRI) are at least partially associated with modifications of cellular communications between these cells. In this study we examined effects of the antidepressant fluoxetine on cultured astrocytes that were, in some cases, pretreated with dexamethasone, a cortisol analog known to trigger depressive disorder. Primary rat astrocytes were purified and treated with dexamethasone and the SSRI fluoxetine in physiological concentrations so that both drugs did not affect cell viability. Expression of interleukin-2 (IL-2) and glia-derived-neurotrophic-factor (GDNF) were analyzed and monitored and cell viability, apoptosis, cluster formation, particle-removing capacity and cell mobility were also monitored. Pre-studies without any drugs on mixed neuron-astrocyte co-cultures suggested that astrocytes interacted with neurons and other brain cells in vitro by actively assembling them into clusters. Treatment of purified astrocytes with dexamethasone significantly decreased their mobility compared to controls but had no effect on cluster formation. Dexamethasone-treated cells removed fewer extracellular particles derived from dead cells and cell debris. Both effects were abolished by simultaneous application of fluoxetine. Intracellular IL-2 increased, while GDNF amount expression was diminished following dexamethasone treatment. Simultaneous administration of fluoxetine reversed dexamethasone-triggered IL-2 elevation but had no effect on decreased GDNF concentration. These results suggest that mobility and growth factor equilibrium of astrocytes are affected by dexamethasone and by fluoxetine and that fluoxetine could reverse some changes induced by dexamethasone.
Asunto(s)
Astrocitos/efectos de los fármacos , Citocinas/metabolismo , Dexametasona/farmacología , Fluoxetina/farmacología , Glucocorticoides/farmacología , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Animales , Apoptosis/efectos de los fármacos , Astrocitos/fisiología , Movimiento Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Técnicas de Cocultivo , Femenino , Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Hipocampo/efectos de los fármacos , Hipocampo/fisiología , Interleucina-2/metabolismo , Masculino , Neuronas/efectos de los fármacos , Neuronas/fisiología , Ratas Sprague-DawleyRESUMEN
We consider a model for the morphology and growth of the fungus-like plant pathogen Phytophthora using the example of Phytophthora plurivora. Here, we are utilizing a correlated random walk describing the density of tips. This random walk incorporates a delay in branching behavior: newly split tips only start to grow after a short while. First, we question the effect of such a delay on the running fronts, for uniform- as well as non-uniform turning kernels. We find that this delay primarily influences the slope of the front and therewith the way of spatial appropriation, and not its velocity. Our theoretical predictions are confirmed by the growth of Phytophthora in concrete experiments performed in Petri dishes. The second question addressed in this paper, concerns the manner tips are interacting, especially the point why tips stop to grow "behind" the interface of the front, respectively in confrontation experiments at the interface between two colonies. The combination of experimental data about the spatially structured time course of the glucose concentration and simulations of a model taking into account both, tips and glucose, reveals that nutrient depletion is most likely the central mechanism of tip interaction and hyphal growth inhibition. We presume that this is the growing mechanism for our kind of Phytophthora in infected plant tissue. Thus, the pathogen will sap its hosts via energy depletion and tissue destruction in infected areas.
Asunto(s)
Modelos Biológicos , Phytophthora/crecimiento & desarrollo , Simulación por Computador , Glucosa/metabolismo , Hifa/crecimiento & desarrollo , Hifa/metabolismo , Phytophthora/metabolismo , Procesos EstocásticosRESUMEN
Metabolic and functional studies of the amyloid precursor protein (APP) in platelets have advanced our understanding of Alzheimer's disease (AD). Here we report that human platelets contain Abeta peptides, process and secrete them constitutively. Platelets generate formerly unkown Abeta-species by differential processing of APP. Release of Abeta peptides were also increased by platelet activation with thrombin, indicating the existence of a regulated exocytotic pathway. We showed that Abeta-levels, Abeta-processing patterns and Abeta-release kinetics were regulated by thrombin. In controls, release of Abeta peptide species (Abeta 1-40/42 and 1-37/38/39/) continued for more than 4 h, while thrombin activated cells ceased secretion after 1 h at large. Treatment of platelets with prostaglandine 2 slowed this process down. Intracellular Abeta peptide concentrations decreased steadily until no peptides could be detected after 20 h (control) or after 4 h (thrombin) in cultured platelets.
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Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/metabolismo , Plaquetas/fisiología , Dinoprostona/metabolismo , Trombina/metabolismo , Plaquetas/metabolismo , Células Cultivadas , Colágeno/metabolismo , Electroforesis en Gel de Poliacrilamida , Exocitosis/fisiología , Espacio Extracelular/metabolismo , Humanos , Inmunoprecipitación , Espacio Intracelular/metabolismo , Cinética , Fragmentos de Péptidos/metabolismo , Factores de TiempoRESUMEN
The diagnostic potential of large A beta-peptide binding particles (LAPs) in the cerebrospinal fluid (CSF) of Alzheimer's dementia (AD) patients and non-AD controls (nAD) was evaluated. LAPs were detected by confocal spectroscopy in both groups with high inter-individual variation in number. Molecular imaging by confocal microscopy revealed that LAPs are heterogeneous superaggregates that could be subdivided morphologically into four main types (LAP 1-4). LAP-4 type, resembling a 'large chain of pearls', was detected in 42.1% of all nAD controls but it was virtually absent in AD patients. LAP-4 type could be selectively removed by protein A beads, a clear indication that it contained immunoglobulins in addition to beta-amyloid peptides (A beta 1-42). We observed a close correlation between LAPs and immunoglobulin G (IgG) concentration in CSF in controls but not in AD patients. Double labeling of LAPs with anti-A beta and anti-IgG antibodies confirmed that LAP-4 type consisted of A beta and IgG aggregates. Our results assign a central role to the immune system in regulating A beta1-42 homeostasis by clustering this peptide in immunocomplexes.
Asunto(s)
Enfermedad de Alzheimer/líquido cefalorraquídeo , Péptidos beta-Amiloides/inmunología , Complejo Antígeno-Anticuerpo/líquido cefalorraquídeo , Autoanticuerpos/líquido cefalorraquídeo , Demencia/líquido cefalorraquídeo , Inmunoglobulina G/líquido cefalorraquídeo , Fragmentos de Péptidos/inmunología , Enfermedad de Alzheimer/inmunología , Péptidos beta-Amiloides/líquido cefalorraquídeo , Autoanticuerpos/clasificación , Biomarcadores/líquido cefalorraquídeo , Estudios de Casos y Controles , Sistema Nervioso Central/inmunología , Demencia/clasificación , Demencia/inmunología , Humanos , Inmunoglobulina G/inmunología , Fragmentos de Péptidos/líquido cefalorraquídeo , Valores de ReferenciaRESUMEN
A newly discovered system of photoreceptors for circadian rhythms works non-visual and responds to blue light (460 nm). We report a longitudinal study in 44 adults, showing that a significant increase in alertness and speed of information processing could be achieved by blue light as compared to normal light.
Asunto(s)
Cognición/fisiología , Luz , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos PilotoRESUMEN
High-dose dienogest (20 mg/day) was used for the treatment of endometriosis in women aged 18-52 years after laparoscopic and histological diagnosis of endometriosis and staging according to the revised American Fertility Society criteria. Treatment efficacy was analyzed objectively by second-look laparoscopy, and serum hormone measurements and evaluation of endometriosis-related symptoms were performed done and side-effects recorded. Compared with other high-dose progestin therapies, treatment with dienogest was shown to be effective even in stage IV endometriosis. The side-effect profile of the high-dose dienogest treatment appears to be highly favorable compared with other treatments. Neither the menopausal symptoms caused by therapy with gonadotropin-releasing hormone agonists nor the adverse androgen-related effects induced by danazol were observed. Therefore, long-term high-dose dienogest therapy can be recommended particularly for women with progressive endometriosis.
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Endometriosis/tratamiento farmacológico , Antagonistas de Hormonas/administración & dosificación , Nandrolona/análogos & derivados , Adulto , Femenino , Antagonistas de Hormonas/efectos adversos , Humanos , Nandrolona/administración & dosificación , Nandrolona/efectos adversos , Proyectos Piloto , Estadísticas no Paramétricas , Resultado del TratamientoRESUMEN
Acid sphingomyelinase (A-SMase) and its reaction product ceramide may play a role in the pathophysiology of depressive disorders and in the therapeutic action of antidepressive drugs. In a prospective case-control study, A-SMase activity was measured in peripheral blood mononuclear cells of 17 patients with a major depressive episode who were free of antidepressant drug therapy for at least 10 days and 8 healthy volunteers. In the patient group, A-SMase activity was correlated to the score (n=17, r=0.64, P=0.005). The patient group exhibited higher A-SMase activity compared to healthy volunteers (T=2.09, df=21.33, P<0.05). In addition, we demonstrate that the antidepressants imipramine and amitriptyline induce a long-term reduction of the activity of A-SMase in cultured cells.
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Química Encefálica/fisiología , Encéfalo/enzimología , Trastorno Depresivo Mayor/enzimología , Esfingomielina Fosfodiesterasa/sangre , Regulación hacia Arriba/fisiología , Adulto , Antidepresivos Tricíclicos/farmacología , Encéfalo/fisiopatología , Química Encefálica/efectos de los fármacos , Estudios de Casos y Controles , Células Cultivadas , Ceramidas/metabolismo , Trastorno Depresivo Mayor/sangre , Trastorno Depresivo Mayor/diagnóstico , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/fisiología , Femenino , Humanos , Masculino , Microdominios de Membrana/efectos de los fármacos , Microdominios de Membrana/metabolismo , Persona de Mediana Edad , Vaina de Mielina/metabolismo , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Estudios Prospectivos , Agregación de Receptores/efectos de los fármacos , Agregación de Receptores/fisiología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Esfingomielina Fosfodiesterasa/análisis , Esfingomielinas/metabolismoRESUMEN
Aging of population, and increasing life expectancy result in an increasing number of patients with dementia. This symptom can be a part of a completely curable disease of the central nervous system (e.g, neuroinflammation), or a disease currently considered irreversible (e.g, Alzheimer's disease, AD). In the latter case, several potentially successful treatment approaches are being tested now, demanding reasonable standards of pre-mortem diagnosis. Cerebrospinal fluid and serum analysis (CSF/serum analysis), whereas routinely performed in neuroinflammatory diseases, still requires standardization to be used as an aid to the clinically based diagnosis of AD. Several AD-related CSF parameters (total tau, phosphorylated forms of tau, Abeta peptides, ApoE genotype, p97, etc.) tested separately or in a combination provide sensitivity and specificity in the range of 85%, the figure commonly expected from a good diagnostic tool. In this review, recently published reports regarding progress in neurochemical pre-mortem diagnosis of dementias are discussed with a focus on an early and differential diagnosis of AD. Novel perspectives offered by recently introduced technologies, e.g, fluorescence correlation spectroscopy (FCS) and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) are briefly discussed.
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Enfermedad de Alzheimer , Consenso , Anciano , Enfermedad de Alzheimer/sangre , Enfermedad de Alzheimer/líquido cefalorraquídeo , Enfermedad de Alzheimer/genética , Precursor de Proteína beta-Amiloide/líquido cefalorraquídeo , Apolipoproteínas E/genética , Biomarcadores/sangre , Biomarcadores/líquido cefalorraquídeo , Diagnóstico Diferencial , Genotipo , Humanos , Immunoblotting , Proteínas Asociadas a Microtúbulos/metabolismo , Neuronas/metabolismo , Fosforilación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Factores de Tiempo , Proteínas tau/líquido cefalorraquídeoRESUMEN
This study was focussed on the identification of the endocytic organelles in chromaffin cells which retrieve large, dense core vesicle (LDCV)-membrane components from the plasma membrane. For this purpose, 'on-cell' capacitance measurements and electron microscopy were employed. We found capacitance steps and capacitance flickers, corresponding to single exo- and endocytic events. The analysis revealed that the total membrane surface of completely fused LDCVs is recycled by large endocytic vesicles and smaller, most likely clathrin-coated vesicles, at approximately the same ratio. These results were confirmed by rapid-freeze immuno-electron microscopy, where an extracellular marker was rapidly internalized into endocytic vesicles that morphologically resembled LDCVs.
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Células Cromafines/ultraestructura , Animales , Bovinos , Membrana Celular/fisiología , Membrana Celular/ultraestructura , Células Cultivadas , Células Cromafines/fisiología , Endocitosis , Potenciales de la Membrana , Microscopía ElectrónicaRESUMEN
RCC1 (regulator of chromosome condensation), a beta propeller chromatin-bound protein, is the guanine nucleotide exchange factor (GEF) for the nuclear GTP binding protein Ran. We report here the 1.8 A crystal structure of a Ran*RCC1 complex in the absence of nucleotide, an intermediate in the multistep GEF reaction. In contrast to previous structures, the phosphate binding region of the nucleotide binding site is perturbed only marginally, possibly due to the presence of a polyvalent anion in the P loop. Biochemical experiments show that a sulfate ion stabilizes the Ran*RCC1 complex and inhibits dissociation by guanine nucleotides. Based on the available structural and biochemical evidence, we present a unified scenario for the GEF mechanism where interaction of the P loop lysine with an acidic residue is a crucial element for the overall reaction.
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Sitios de Unión , Proteínas de Ciclo Celular , Proteínas de Unión al ADN/química , Factores de Intercambio de Guanina Nucleótido/química , Proteínas Nucleares/química , Estructura Terciaria de Proteína , Proteína de Unión al GTP ran/química , Cristalografía por Rayos X , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Factores de Intercambio de Guanina Nucleótido/genética , Factores de Intercambio de Guanina Nucleótido/metabolismo , Guanosina Difosfato/metabolismo , Humanos , Modelos Moleculares , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Polielectrolitos , Polímeros/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteína de Unión al GTP ran/genética , Proteína de Unión al GTP ran/metabolismoRESUMEN
Exocytosis and 'kiss-and-run' secretion coexist in chromaffin cells. Our findings suggest that these mechanisms are closely related, based on their common molecular machinery. Here we present a model that describes how chromaffin cells regulate catecholamine release by switching the mode of secretion between the two pathways, a process controlled by phosphorylation. Stimulation-dependent vesicle-plasma membrane interactions in chromaffin cells were analysed by simultaneous 'on-cell' capacitance and conductance measurements, a technique that allows the monitoring of single vesicles. Capacitance steps represent fusions of large dense-core vesicles with the plasma membrane, whereas capacitance flickers correspond to transient connections of the vesicle lumen with the extracellular space. All these events require the presence of extracellular calcium in millimolar concentrations. 'Kiss-and-run' type of release is enhanced by the kinase inhibitor staurosporine, which suggests that this secretion mode is regulated by protein phosphorylation. We also observed capacitance bursts, which most probably represent 'hot spots' of secretion and we found that 'kiss-and-run' is the prevalent mechanism during these episodes. The significance of 'kiss-and run' for neurohormone release is even higher at physiological temperature, because up to half of all secretion events are mediated by this mechanism.
Asunto(s)
Células Cromafines/fisiología , Exocitosis/fisiología , Animales , Calcio/metabolismo , Carbacol/farmacología , Bovinos , Células Cultivadas , Células Cromafines/enzimología , Células Cromafines/metabolismo , Medios de Cultivo/farmacología , Capacidad Eléctrica , Estimulación Eléctrica , Inhibidores Enzimáticos/farmacología , Exocitosis/efectos de los fármacos , Modelos Biológicos , Técnicas de Placa-Clamp , Fosforilación , Inhibidores de Proteínas Quinasas , Estaurosporina/farmacologíaRESUMEN
PURPOSE: To determine whether the clinical features of tonic seizures (TSZ) are useful for lateralization of epileptic syndromes and the differential diagnosis of focal epileptic syndromes. METHODS: From a group of 481 patients, 123 patients with TSZ (44 females; mean age, 22.9 years; mean age at onset, 7 years; mean duration of epilepsy, 16 years) were selected. A total of 1595 epileptic seizures, documented during videoelectroencephalographic monitoring, were analyzed. Patients who had had surgery for epilepsy previously were excluded. Seizures were classified using a semiological seizure classification. Epilepsy syndromes were classified using all test data (electroencephalography, magnetic resonance imaging, computed tomography, positron emission tomography, and single-photon emission tomography). Data were compared using chi2 analysis or the Fisher exact test. RESULTS: More patients with TSZ had extratemporal than temporal lobe epilepsies (79% vs. 1.7%; p < 0.0001) among those with an epilepsy localized to one lobe (n = 306). In the 123 patients, TSZ were part of 170 different seizure evolutions. Seizure evolutions began with TSZ as the first seizure type more often in patients with frontal lobe epilepsy (FLE) compared with patients with parieto-occipital lobe epilepsy (POLE) (40% in POLE vs. 67% in FLE; p < 0.05). In contrast, TSZ in POLE were more likely to be preceded by auras (50% in POLE vs. 26% in FLE; p < 0.05). TSZ were bilateral in 129 (76%) and unilateral in 41 (24%) seizure evolutions. Unilateral TSZ correctly lateralized the epilepsy syndrome to the contralateral hemisphere. CONCLUSION: Analysis of seizure semiology and evolution in patients with TSZ is helpful for differentiating between focal epilepsies of temporal, frontal, and parieto-occipital origin. Unilateral TSZ provide useful information for the lateralization of the epileptic syndrome.
Asunto(s)
Epilepsias Parciales/diagnóstico , Epilepsia Generalizada/diagnóstico , Lateralidad Funcional/fisiología , Adulto , Edad de Inicio , Diagnóstico Diferencial , Electroencefalografía/estadística & datos numéricos , Epilepsias Parciales/fisiopatología , Epilepsia Generalizada/fisiopatología , Epilepsia del Lóbulo Temporal/diagnóstico , Epilepsia del Lóbulo Temporal/fisiopatología , Femenino , Humanos , Masculino , Grabación de Cinta de VideoRESUMEN
PURPOSE: Comparison of regional reduction of GABA receptor binding and seizure onset zone in patients with extratemporal epilepsy due to focal cortical dysplasia. METHODS: Two patients with frontal lobe epilepsy who remained seizure free after partial frontal lobe resection were investigated with magnetic resonance imaging, positron emission tomography (PET) with 18F-fluoro-deoxy-glucose (FDG) and 11C-flumazenil, subdural EEG-video recordings, and postoperative benzodiazepine (BDZ)-receptor autoradiography. RESULTS: The area of reduced BDZ-receptor binding as documented by preoperative flumazenil-PET and postoperative BDZ-receptor autoradiography corresponded to the seizure onset zone and was smaller than the interictal hypometabolism documented by FDG-PET. CONCLUSION: Flumazenil-PET is a useful tool for localization of the epileptogenic zone in patients with extratemporal epilepsy caused by focal cortical dysplasia. Neuronal distribution of BDZ-receptor density confirms in vivo flumazenil-PET findings. The regional reduction of BDZ-receptor binding in focal cortical dysplasia seems to be confined to the seizure onset zone and not to the extent of dysplastic cortex.