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1.
Oecologia ; 198(4): 917-931, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35412091

RESUMEN

Free-ranging predator diet estimation is commonly achieved by applying molecular-based tracers because direct observation is not logistically feasible or robust. However, tracers typically do not represent all dietary macronutrients, which likely obscures resource use as prey proximate composition varies and tissue consumption can be specific. For example, polar bears (Ursus maritimus) preferentially consume blubber, yet diets have been estimated using fatty acids based on prey blubber or stable isotopes of lipid-extracted prey muscle, neither of which represent both protein and lipid macronutrient contributions. Further, additional bias can be introduced because dietary fat is known to be flexibly routed beyond short-term energy production and storage. We address this problem by simultaneously accounting for protein and lipid assimilation using carbon and nitrogen isotope compositions of lipid-containing prey muscle and blubber to infer summer/fall diet composition and macronutrient proportions from Chukchi Sea polar bear guard hair (n = 229) sampled each spring between 2008 and 2017. Inclusion of blubber (85-95% lipid by dry mass) expanded the isotope mixing space and improved separation among prey species. Ice-associated seals, including nutritionally dependent pups, were the primary prey in summer/fall diets with lower contributions by Pacific walruses (Odobenus rosmarus) and whales. Percent blubber estimates confirmed preferential selection of this tissue and represented the highest documented lipid assimilation for any animal species. Our results offer an improved understanding of summer/fall prey macronutrient usage by Chukchi Sea polar bears which likely coincides with a nutritional bottleneck as the sea ice minimum is approached.


Asunto(s)
Ursidae , Animales , Regiones Árticas , Dieta , Ácidos Grasos/metabolismo , Cubierta de Hielo , Nutrientes , Ursidae/fisiología , Morsas/metabolismo
2.
Horm Behav ; 128: 104907, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33259797

RESUMEN

Many seasonally breeding animals exhibit a threshold day length (critical photoperiod; CPP) for gonadal growth, and populations breeding at higher latitudes typically have a higher CPP. Much less is known about latitudinal variation in CPP in migratory population that winter away from their breeding range and must time their reproduction to match favorable conditions at their destination. To address the relationship between migration, breeding latitude, and CPP, we held two closely related songbird populations in a common environment. One population is resident (Junco hyemalis carolinensis), the other winters in sympatry with the residents but migrates north to breed (Junco hyemalis hyemalis). We gradually increased photoperiod and measured indices of readiness to migrate (fat score, body mass) and breed (cloacal protuberance volume, baseline testosterone, and gonadotropin releasing hormone challenged testosterone). To estimate breeding latitude, we measured hydrogen isotopes in feathers grown the preceding year. As we predicted, we found a higher CPP in migrants than residents, and a higher CPP among migrants deriving from higher as opposed to lower latitudes. Migrants also terminated breeding earlier than residents, indicating a shorter breeding season. To our knowledge, this is a first demonstration of latitudinal variation in CPP-dependent reproductive timing in bird populations that co-exist in the non-breeding season but breed at different latitudes. We conclude that bird populations appear to exhibit local adaptation in reproductive timing by relying on differential CPP response that is predictive of future conditions on the breeding ground.


Asunto(s)
Passeriformes , Pájaros Cantores , Animales , Fotoperiodo , Reproducción , Estaciones del Año , Simpatría
3.
Oecologia ; 188(1): 263-275, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29948317

RESUMEN

Detailed information on the nutrition of free-ranging mammals contributes to the understanding of life history requirements, yet is often quite limited temporally for most species. Reliable dietary inferences can be made by analyzing the stable carbon (C) and nitrogen (N) isotopic values (δ13C and δ15N) of some consumer tissues; exactly which tissue is utilized dictates the inferential scope. Steller sea lion (SSL) vibrissae are grown continuously without shedding and thus provide a continuous multi-year record of dietary consumption. We applied a novel kernel density approach to compare the δ13C and δ15N values along the length of SSL vibrissae with δ13C and δ15N distributions of potential prey species. This resulted in time-series of proportion estimates of dietary consumption for individual SSL. Substantial overlap in δ13C and δ15N distributions for prey species prevented a discrete species-scale assessment of SSL diets; however, a post hoc correlational analysis of diet proportion estimates revealed grouping by trophic level. Our findings suggest that adult female SSL diets in the western and central Aleutian Islands shift significantly according to season: diets contain a higher proportion of lower trophic level species (Pacific Ocean perch, northern rockfish, Atka mackerel and walleye pollock) in the summer, whereas in the winter SSL consume a much more diverse diet which includes a greater proportion of higher trophic level species (arrowtooth flounder, Kamchatka flounder, darkfin sculpin, Pacific cod, Pacific octopus, rock sole, snailfish, and yellow Irish lord).


Asunto(s)
Perciformes , Leones Marinos , Alaska , Animales , Dieta , Femenino , Vibrisas
4.
Obes Sci Pract ; 3(1): 83-94, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-28392934

RESUMEN

PURPOSE: Half of adult cancer survivors under age 50 years are obese. Excess body weight is associated with cancer recurrence, and effective weight loss interventions for younger cancer survivors are needed. Commercially available, online weight loss programmes are readily accessible, but few have been studied in this population. This study employed a single-arm, pre-post intervention (baseline-6 month/baseline-12 month comparisons) to preliminarily explore feasibility, efficacy and safety of an online, commercially available weight loss programme in breast (n = 30) and testicular (n = 16) cancer survivors under age 50 years. METHODS: The intervention included three daily components: exercise, nutritional/behavioural modification strategies and health lessons. Intention-to-treat and completers analyses were conducted. Feasibility was measured by participation (number of participants enrolled/number screened), retention (number of participants attending 6/12 month study visit/number of enrolled) and self-reported adherence rates (average of mean percent adherence to each of the three intervention components). Efficacy was assessed by changes in initial weight (percent weight loss). Safety was assessed by adverse events. RESULTS: The mean participation rate was 42%. The retention rate was 59% at 6 and 49% at 12 months. The adherence rate for all participants (completers/dropouts/lost-to-follow-up) was 50.1% at 6 and 44% at 12 months. Completers reported adherence rates of 68% at 12 months. Study participants lost 5.3% body weight at 12 months; completers lost 9%. Only three unexpected adverse events (unrelated to the intervention) were reported. CONCLUSION: Clinically significant weight loss was observed, although retention rates were low. Findings generally support preliminary feasibility, efficacy and safety of this online weight loss programme, and future randomized control trials should be explored.

5.
Physiol Biochem Zool ; 89(3): 182-97, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27153128

RESUMEN

There has been considerable emphasis on understanding isotopic discrimination for diet estimation in omnivores. However, discrimination may differ for carnivores, particularly species that consume lipid-rich diets. Here, we examined the potential implications of several factors when using stable isotopes to estimate the diets of bears, which can consume lipid-rich diets and, alternatively, fast for weeks to months. We conducted feeding trials with captive brown bears (Ursus arctos) and polar bears (Ursus maritimus). As dietary lipid content increased to ∼90%, we observed increasing differences between blood plasma and diets that had not been lipid extracted (∆(13)Ctissue-bulk diet) and slightly decreasing differences between plasma δ(13)C and lipid-extracted diet. Plasma Δ(15)Ntissue-bulk diet increased with increasing protein content for the four polar bears in this study and data for other mammals from previous studies that were fed purely carnivorous diets. Four adult and four yearling brown bears that fasted 120 d had plasma δ(15)N values that changed by <±2‰. Fasting bears exhibited no trend in plasma δ(13)C. Isotopic incorporation in red blood cells and whole blood was ≥6 mo in subadult and adult bears, which is considerably longer than previously measured in younger and smaller black bears (Ursus americanus). Our results suggest that short-term fasting in carnivores has minimal effects on δ(13)C and δ(15)N discrimination between predators and their prey but that dietary lipid content is an important factor directly affecting δ(13)C discrimination and indirectly affecting δ(15)N discrimination via the inverse relationship with dietary protein content.


Asunto(s)
Alimentación Animal/análisis , Dieta/veterinaria , Grasas de la Dieta/metabolismo , Privación de Alimentos , Lípidos/química , Ursidae/fisiología , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Animales de Zoológico , Grasas de la Dieta/análisis , Femenino , Análisis de los Alimentos , Hibernación/fisiología , Marcaje Isotópico , Masculino
6.
Eur J Cancer Care (Engl) ; 17(5): 444-53, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18637116

RESUMEN

The aim of this study was to explore the experience of chemotherapy-related nausea in patients with cancer. A qualitative study was carried out with 17 patients who had experienced nausea during their chemotherapy in the UK and USA. Nausea was described as distressing and complex symptom. Patients attempted to construct an understanding of nausea using cognitive processes such as analysing their experience of nausea and related symptoms, attributing causation to nausea and comparing their experiences not only to their own expectations, but also to others' symptom experiences. A number of concurrent and associated symptoms linked with nausea were identified. Preliminary evidence emerged for nausea as part of a cluster of symptoms. Anti-emetic medication, provider-directed management strategies and self-management strategies were used by patients to minimize the effects of nausea. Self-management techniques, such as dietary strategies, were rooted in participants' understanding of nausea and their beliefs about what caused nausea, and there was little evidence of guidance from professionals beyond advice about medication management. This study reveals some of the complexities behind chemotherapy-induced nausea, including a potential symptom cluster, and contributes towards a clearer understanding of this symptom and its effects on patients' lives.


Asunto(s)
Antieméticos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Náusea/inducido químicamente , Neoplasias/tratamiento farmacológico , Adaptación Psicológica , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Náusea/prevención & control , Náusea/psicología , Neoplasias/psicología , Calidad de Vida
7.
Rev Stomatol Chir Maxillofac ; 108(3): 234-7, 2007 Jun.
Artículo en Francés | MEDLINE | ID: mdl-17532353

RESUMEN

INTRODUCTION: The closure of scalp defects requires various procedures, but unfortunately with a high rate of sequels. OBSERVATION: The authors report their experience regarding a large pilomatrixoma of the scalp. The closure of an 8 by 10 cm defect resulting from excision was achieved using a simple tissular extension device during 20 days. The scar aspect was very satisfactory. The device is derived from Cohn's model. It is made of simple and widely used material (vascular lacks, staples). DISCUSSION: This simplicity and efficiency of tissular extension devices has been proved. Nevertheless, their use may be restricted. This limitation often results from a high cost and difficulty in applying the adequate tension to the wound edges. Excessive tension may lead to cutaneous necrosis. The use of a simple device derived from Cohn's model seems interesting considering its efficiency, reliability, and low cost.


Asunto(s)
Enfermedades del Cabello/cirugía , Pilomatrixoma/cirugía , Cuero Cabelludo/cirugía , Neoplasias Cutáneas/cirugía , Expansión de Tejido/instrumentación , Adulto , Humanos , Masculino , Procedimientos de Cirugía Plástica/instrumentación
8.
Anim Genet ; 33(6): 441-7, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12464019

RESUMEN

The aim of this study was to refine the localization of the receptor locus for fimbriae F4ac. Small intestinal enterocyte preparations from 187 pigs were phenotyped by an in vitro adhesion test using two strains of Escherichia coli representing the variants F4ab and F4ac. The three-generation pedigree comprised eight founders, 18 F1 and 174 F2 animals, for a total of 200 pigs available for the linkage analysis. Results of the adhesion tests on 171 F2 pigs slaughtered at 8 weeks of age show that 23.5% of the pigs were adhesive for F4ab and non-adhesive for F4ac (phenotype F4abR+/F4acR-; R means receptor). Pigs of this phenotype were characterized by a weak adhesion receptor for F4ab. No pigs were found expressing only F4acR and lacking F4abR. Receptors for F4ab and F4ac (F4abR+/F4acR+) were expressed by 54.5% of the pigs. Animals of this phenotype strongly bound both F4ab and F4ac E. coli. In the segregation study, the serum transferrin (TF) gene and 10 microsatellites on chromosome 13 were linked with F4acR (recombination fractions (theta) between 0.00 and 0.11 and lod score values (Z) between 11.4 and 40.4). The 11-point analysis indicates the F4acR locus was located in the interval S0068-Sw1030 close to S0075 and Sw225, with recombination fractions (theta) of 0.05 between F4acR and S0068, 0.04 with Sw1030, and 0.00 with S0075 and Sw225. The lack of pigs displaying the F4abR-/F4acR+ phenotype and the presence of two phenotypes for F4abR (a strong receptor present in phenotype F4abR+/F4acR+ and a weak receptor in phenotype F4abR+/F4acR-) led us to conclude that the receptor for F4ac binds F4ab bacteria as well, and that it is controlled by one gene localized between S0068 and Sw1030 on chromosome 13.


Asunto(s)
Adhesión Bacteriana/genética , Infecciones por Escherichia coli/veterinaria , Escherichia coli/metabolismo , Fimbrias Bacterianas/metabolismo , Enfermedades de los Porcinos/microbiología , Porcinos/genética , Animales , Mapeo Cromosómico/veterinaria , Cruzamientos Genéticos , Infecciones por Escherichia coli/genética , Infecciones por Escherichia coli/microbiología , Femenino , Fimbrias Bacterianas/microbiología , Ligamiento Genético , Técnicas In Vitro , Enfermedades Intestinales/genética , Enfermedades Intestinales/microbiología , Enfermedades Intestinales/veterinaria , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiología , Masculino , Repeticiones de Microsatélite/genética , Fenotipo , Reacción en Cadena de la Polimerasa/veterinaria , Enfermedades de los Porcinos/genética , Enfermedades de los Porcinos/metabolismo , Transferrina/genética , Transferrina/metabolismo
9.
Br J Oral Maxillofac Surg ; 40(6): 497-503, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12464208

RESUMEN

Many vascular lesions involve the lip. We present the clinical and imaging findings of vascular lesions, including haemangiomas and vascular malformations. We review the changing role of surgery and other treatments in the management of each type of lesion. Haemangiomas are treated surgically only when lip function is substantially impaired. Superselective embolisation is the treatment of choice for arteriovenous malformations, whereas capillary-venous malformations are best treated by operation together with intralesional injection of fibrosing agents. Capillary malformations are usually treated with laser.


Asunto(s)
Malformaciones Arteriovenosas/terapia , Hemangioma/cirugía , Enfermedades de los Labios/terapia , Labio/irrigación sanguínea , Adolescente , Malformaciones Arteriovenosas/diagnóstico , Niño , Embolización Terapéutica , Párpados/irrigación sanguínea , Femenino , Hemangioma/diagnóstico , Humanos , Lactante , Terapia por Láser , Enfermedades de los Labios/diagnóstico , Neoplasias de los Labios/diagnóstico , Neoplasias de los Labios/cirugía , Masculino
10.
Ann Hematol ; 81(7): 410-3, 2002 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12185517

RESUMEN

Nonmyeloablative allogeneic stem cell transplantation (NMASCT) can be used to exploit the graft-versus-tumor (GVT) potential of allogeneic donor cells in the setting of reduced conditioning regimen toxicity. This approach is particularly attractive for patients who have received extensive prior therapy and are poor candidates for traditional allogeneic stem cell transplantation. However, toxicity in heavily pretreated patients remains uncertain. Additional immunosuppression in already immunocompromised patients may result in unexpected toxicity. We report a case of probable progressive multifocal leukoencephalopathy (PML) responsive to interleukin-2 (IL-2) following a NMASCT in a 29-year-old woman with relapsed Hodgkin's lymphoma. The patient developed severe neurological symptoms approximately 6 weeks following NMASCT associated with low CD4+ cell counts and magnetic resonance imaging (MRI) was consistent with PML. IL-2 therapy resulted in increasing CD4+ counts and progressive resolution of neurological symptoms. Disruption of IL-2 therapy led to neurological deterioration, which responded to reinstitution of IL-2 therapy. The patient's lymphoma initially progressed following NMASCT, but has responded to donor leukocyte infusions (DLI). This case reiterates the potent GVT potential of NMASCT in patients with Hodgkin's disease. However, it demonstrates the potential for severe complications related to immunosuppression, especially in heavily pretreated patients. The toxicity after NMASCT should not be understated and will need to be explored further.


Asunto(s)
Enfermedad de Hodgkin/complicaciones , Enfermedad de Hodgkin/cirugía , Interleucina-2/uso terapéutico , Leucoencefalopatía Multifocal Progresiva/tratamiento farmacológico , Leucoencefalopatía Multifocal Progresiva/etiología , Trasplante de Células Madre/efectos adversos , Adulto , Femenino , Enfermedad de Hodgkin/terapia , Humanos , Terapia de Inmunosupresión/efectos adversos , Transfusión de Leucocitos , Leucoencefalopatía Multifocal Progresiva/diagnóstico , Hepatopatías/diagnóstico por imagen , Hepatopatías/etiología , Imagen por Resonancia Magnética , Recurrencia Local de Neoplasia , Tomografía Computarizada por Rayos X , Trasplante Homólogo
11.
News Physiol Sci ; 17: 138-43, 2002 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12136040

RESUMEN

Unitary synaptic currents in hippocampus show small variability. Experimental evidence suggests that the neuron is endowed with mechanisms to reduce location-dependent differences in amplitude and time course of synaptic events, contributing to small variability. These mechanisms may allow the neuron to count individual quanta and thereby linearize integration of unitary events.


Asunto(s)
Modelos Neurológicos , Vías Nerviosas/fisiología , Sinapsis/fisiología , Animales , Modelos Lineales
12.
Vet J ; 163(3): 311-8, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-12090774

RESUMEN

Sensorineural deafness is a common congenital disorder in Dalmatians and is genetically transmitted. Different modes of inheritance have been proposed and the objective of this study was to study these by segregation analyses using maximum likelihood procedures. Data from 33 complete Dalmatian families were collected and data from 56 single Dalmatians added. This resulted in a total of 575 dogs with 357 known phenotypes. All dogs were clinically evaluated and electrophysiologically tested with brainstem auditory evoked responses. The prevalence of deafness was 16.5% (9.4% unilaterally deaf, 7.1% bilaterally deaf). Females were 4.4% more affected than males but this difference was not significant. Within the same litter, different phenotypic expressions of deafness occurred, which suggested different expressions of the disease. In addition, two data sets were analysed: the first included normal, uni- and bilaterally deaf dogs, the second had normal and deaf Dalmatians. We found that a recessive allele at a single biallelic major locus fitted our data best, although an incomplete penetrance of the recessive homozygotes was observed.


Asunto(s)
Enfermedades de los Perros/genética , Pérdida Auditiva Sensorineural/veterinaria , Animales , Tronco Encefálico/patología , Perros , Potenciales Evocados Auditivos , Femenino , Genes Recesivos , Pérdida Auditiva Sensorineural/genética , Masculino , Linaje , Prevalencia , Factores Sexuales
13.
Rev Stomatol Chir Maxillofac ; 102(3-4): 190-200, 2001 Jun.
Artículo en Francés | MEDLINE | ID: mdl-11577473

RESUMEN

Many authors use a preliminary orthopedic procedure before cleft lip and palate surgical closure in order to prevent possible bone distortion following the rupture of the muscle belts resulting from the cleft. Actually, this is generally not only an orthopedic treatment but rather a surgical orthopedic step which includes lip adhesion before the surgical closure of the clefts. Following the procedures proposed by Georgiade and Latham, we have used since 1996 a treatment based on traction applied with an elastic chain on splints attached by transmaxillary pins for certain types of clefts, namely unilateral complete clefts with endognathy of the small fragment, unilateral complete clefts larger than 7 mm, bilateral wide complete clefts with premaxilla protrusion, and bilateral wide complete clefts with collapsus and premaxillary protrusion. Technical procedures vary with the type of cleft. Standard procedures with or without jacks are used for the other types of complete clefts. These orthopedic procedures with elastic traction are performed between the 3rd and 6th week, before lip adhesion of the upper part of the lip (combined with release of skin and subcutaneous tissues from the underlying alar cartilage). A palatine plate with or without a jack, fitted most of the time with a spring for nostril support, is then inserted until surgical closure.


Asunto(s)
Labio Leporino/terapia , Fisura del Paladar/terapia , Maxilar/anomalías , Aparatos Ortodóncicos Funcionales , Obturadores Palatinos , Clavos Ortopédicos , Labio Leporino/cirugía , Fisura del Paladar/cirugía , Diseño de Prótesis Dental , Procedimientos Quirúrgicos Dermatologicos , Humanos , Labio/cirugía , Maxilar/cirugía , Nariz/cirugía , Diseño de Aparato Ortodóncico , Férulas (Fijadores)
14.
J Neurochem ; 79(1): 9-16, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11595752

RESUMEN

To investigate the existence of 5'-region(s) of human choline acetyltransferase (hChAT) mRNA in placenta we analyzed the presence or absence of ChAT 5'-untranslated regions (UTR) in human neuronal and non-neuronal cells. Total RNA from human spinal cord, placenta, cultured choriocarcinoma JEG-3 and neuroblastoma CHP126 and MC-IXC cells was reverse transcribed and used for polymerase chain reaction amplification (RT-PCR). We used a sense primer located in the 5'-flanking region, in the previously defined intronic sequence and an anti-sense primer located in the common coding exon 2 of the hChAT gene. An amplified product of 567 bp in size was obtained only in human placenta and in JEG-3 cells whereas it was absent in spinal cord, CHP126 and MC-IXC cells. It was designated 'H-type' of ChAT mRNA. Whereas CHP126 produced the R- and N-type of ChAT mRNAs, no transcript of the N-and R-type was detected in JEG-3 and human placenta. In addition, CHP126 and JEG-3 cells and placenta showed the expression of the M-type of ChAT mRNA. The identity of the amplified 567 bp product (H-type) was confirmed by Southern hybridization and sequencing. The nucleotide sequence of the amplified fragment in placenta revealed the existence of a previously unknown type of ChAT mRNA produced by alternative splicing. Using primer extension we further determined the transcription initiation site of the H-type hChAT mRNA in placenta. These results demonstrate the expression of a novel ChAT mRNA isoform in human placenta in addition to the M-type. These data may be possibly explained by the presence of a placenta specific promoter in the ChAT gene, which might be the proximal promoter P1.


Asunto(s)
Colina O-Acetiltransferasa/genética , Exones , Placenta/enzimología , Secuencia de Aminoácidos , Secuencia de Bases , Southern Blotting , Coriocarcinoma/enzimología , Femenino , Humanos , Datos de Secuencia Molecular , Neuroblastoma/enzimología , Embarazo , ARN Mensajero/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Médula Espinal/enzimología , Trofoblastos/enzimología , Células Tumorales Cultivadas , Neoplasias Uterinas/enzimología
15.
J Neurophysiol ; 86(1): 492-502, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11431527

RESUMEN

The role of glycinergic and GABAergic systems in mediating spontaneous synaptic transmission in newly formed neural networks was examined in motoneurons in the developing rat spinal cord. Properties of action potential-independent miniature inhibitory postsynaptic currents (mIPSCs) mediated by glycine and GABA(A) receptors (GlyR and GABA(A)R) were studied in spinal cord slices of 17- to 18-day-old embryos (E17-18) and 1- to 3-day-old postnatal rats (P1-3). mIPSC frequency and amplitude significantly increased after birth, while their decay time decreased. To determine the contribution of glycinergic and GABAergic synapses to those changes, GlyR- and GABA(A)R-mediated mIPSCs were isolated based on their pharmacological properties. Two populations of pharmacologically distinct mIPSCs were recorded in the presence of glycine or GABA(A) receptors antagonists: bicuculline-resistant, fast-decaying GlyR-mediated mIPSCs, and strychnine-resistant, slow-decaying GABA(A)R-mediated mIPSCs. The frequency of GABA(A)R-mediated mIPSCs was fourfold higher than that of GlyR-mediated mIPSCs at E17-18, indicating that GABAergic synaptic sites were functionally dominant at early stages of neural network formation. Properties of GABA(A)R-mediated mIPSC amplitude fluctuations changed from primarily unimodal skewed distribution at E17-18 to Gaussian mixtures with two to three discrete components at P1-3. A developmental shift from primarily long-duration GABAergic mIPSCs to short-duration glycinergic mIPSCs was evident after birth, when the frequency of GlyR-mediated mIPSCs increased 10-fold. This finding suggested that either the number of glycinergic synapses or the probability of vesicular glycine release increased during the period studied. The increased frequency of GlyR-mediated mIPSCs was associated with more than a twofold increase in their mean amplitude, and in the number of motoneurons in which mIPSC amplitude fluctuations were best fitted by multi-component Gaussian curves. A third subpopulation of mIPSCs was apparent in the absence of glycine and GABA(A) receptor antagonists: mIPSCs with both fast and slow decaying components. Based on their dual-component decay time and their suppression by either strychnine or bicuculline, we assumed that these were generated by the activation of co-localized postsynaptic glycine and GABA(A) receptors. The contribution of mixed glycine-GABA synaptic sites to the generation of mIPSCs did not change after birth. The developmental switch from predominantly long-duration GABAergic inhibitory synaptic currents to short-duration glycinergic currents might serve as a mechanism regulating neuronal excitation in the developing spinal networks.


Asunto(s)
Glicina/fisiología , Neuronas Motoras/fisiología , Médula Espinal/citología , Médula Espinal/embriología , Transmisión Sináptica/fisiología , Ácido gamma-Aminobutírico/fisiología , Animales , Bicuculina/farmacología , Feto/citología , Antagonistas del GABA/farmacología , Glicina/farmacología , Glicinérgicos/farmacología , Técnicas In Vitro , Potenciales de la Membrana/fisiología , Inhibición Neural/fisiología , Técnicas de Placa-Clamp , Ratas , Ratas Sprague-Dawley , Médula Espinal/fisiología , Estricnina/farmacología , Transmisión Sináptica/efectos de los fármacos , Ácido gamma-Aminobutírico/farmacología
16.
J Neurophysiol ; 84(3): 1445-52, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10980017

RESUMEN

Most excitatory synapses on neocortical pyramidal cells are located on dendrites, which are endowed with a variety of active conductances. The main origin for action potentials is thought to be at the initial segment of the axon, although local regenerative activity can be initiated in the dendrites. The transfer characteristics of synaptic voltage and charge along the dendrite to the soma remains largely unknown, although this is an essential determinant of neural input-output transformations. Here we perform dual whole-cell recordings from layer V pyramidal cells in slices from somatosensory cortex of juvenile rats. Steady-state and sinusoidal current injections are applied to characterize the voltage transfer characteristics of the apical dendrite under resting conditions. Furthermore, dendrosomatic charge and voltage transfer are determined by mimicking synapses via dynamic current-clamping. We find that around rest, the dendrite behaves like a linear cable. The cutoff frequency for somatopetal current transfer is around 4 Hz, i.e., synaptic inputs are heavily low-pass filtered. In agreement with linearity, transfer resistances are reciprocal in opposite directions, and the centroids of the synaptic time course are on the order of the membrane time constant. Transfer of excitatory postsynaptic potential (EPSP) charge, but not peak amplitude, is positively correlated with membrane potential. We conclude that the integrative properties of dendrites in infragranular neocortical pyramidal cells appear to be linear near resting membrane potential. However, at polarized potentials charge transferred is voltage-dependent with a loss of charge at hyperpolarized and a gain of charge at depolarized potentials.


Asunto(s)
Dendritas/fisiología , Neocórtex/fisiología , Células Piramidales/fisiología , Animales , Estimulación Eléctrica , Electrofisiología , Transferencia de Energía/fisiología , Potenciales Postsinápticos Excitadores/fisiología , Femenino , Técnicas In Vitro , Modelos Lineales , Masculino , Potenciales de la Membrana/fisiología , Neocórtex/citología , Técnicas de Placa-Clamp , Ratas , Ratas Sprague-Dawley , Corteza Somatosensorial/citología , Corteza Somatosensorial/fisiología
17.
Ann Chir Plast Esthet ; 45(3): 385-404, 2000 Jun.
Artículo en Francés | MEDLINE | ID: mdl-10929465

RESUMEN

The authors report the particularities of the cranio-maxillofacial skeleton and the aims of the reconstruction procedures: osteogenesis, osteoconduction, osteoinduction. They review the various procedures, their abilities, some technical notes, their advantages and disadvantages. They analyse in order: classical bone autografts, pedicled bone flaps (arterio-osseous, fascio-osseous, myo-osseous flaps), free bone flaps, classical and pedicled periosteal transplantations. They also describe the mechanical and biological procedures of bone stimulation: bone distraction, guided bone regeneration, bone growth factors, and the biomaterials, especially coral and enosseous implants. They conclude that, in facial reconstruction, the best material is the autologous bone membranous and vascularized.


Asunto(s)
Huesos Faciales/cirugía , Procedimientos de Cirugía Plástica/métodos , Trasplante Óseo/métodos , Humanos , Colgajos Quirúrgicos
18.
Rev Stomatol Chir Maxillofac ; 100(4): 184-6, 1999 Oct.
Artículo en Francés | MEDLINE | ID: mdl-10599126

RESUMEN

Usual imaging diagnostic for salivary glands is sialography. Sialography is not stripped of disadvantages and failures. The MRI-sialography is an examination which is carried out without any injection of contrast's product (without catheterization or intravenous injection). It is thus noninvasive and painless. The complete study of salivary gland and its ducts is always possible and could not be blocked by local or loco-regional conditions. It allows exploration of several salivary glands in the same time. We think that the MRI-sialography must find its place in the diagnosis arsenal for salivary pathology in spite of its current handicaps represented by its cost and the difficulty of access to the apparatuses.


Asunto(s)
Imagen por Resonancia Magnética , Conductos Salivales/patología , Enfermedades de las Glándulas Salivales/diagnóstico , Medios de Contraste , Humanos , Imagen por Resonancia Magnética/economía , Imagen por Resonancia Magnética/instrumentación , Imagen por Resonancia Magnética/métodos , Enfermedades de las Glándulas Salivales/diagnóstico por imagen , Sialografía
19.
J Physiol ; 520 Pt 2: 513-25, 1999 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-10523419

RESUMEN

1. Excitatory postsynaptic currents (EPSCs) were evoked at synapses formed by Schaffer collaterals/commissural (CA3) axons with CA1 pyramidal cells using the rat hippocampal slice preparation. Long-term potentiation (LTP) was induced at these synapses using a pairing protocol, with 50 microM d,l-APV present in the artificial cerebrospinal fluid (ACSF). 2. Quantal analysis of the amplitudes of the control and conditioned EPSCs showed that the enhancement of synaptic strength was due entirely to an increase in quantal content of the EPSC. No change occurred in the quantal current. 3. These results were compared with those obtained from a previous quantal analysis of LTP induced in normal ACSF, where both quantal current and quantal content increased. The results suggest that calcium entering via NMDA receptors initiates the signalling cascade that results in enhanced AMPA currents because it is adding to cytoplasmic calcium from other sources to reach a threshold for this signalling pathway, or because calcium entering via NMDA receptors specifically activates this signalling pathway.


Asunto(s)
Hipocampo/fisiología , Potenciación a Largo Plazo , Sinapsis/fisiología , Animales , Calcio/metabolismo , Líquido Cefalorraquídeo , Electrofisiología , Potenciales Postsinápticos Excitadores/fisiología , Femenino , Hipocampo/metabolismo , Masculino , Quinoxalinas/farmacología , Ratas , Ratas Wistar , Receptores de N-Metil-D-Aspartato/metabolismo , Transducción de Señal/fisiología , Valina/análogos & derivados , Valina/farmacología
20.
Anim Genet ; 30(4): 309-12, 1999 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10467707

RESUMEN

Vitamin C deficient pigs, when fed a diet lacking L-ascorbic acid (AscA), manifest deformity of the legs, multiple fractures, osteoporosis, growth retardation and haemorrhagic tendencies. This trait was shown by others to be controlled by a single autosomal recessive allele designated as od (osteogenic disorder). The inability of AscA biosynthesis in primates and guinea pigs that exhibit similar symptoms, when they are not supplemented with AscA in the food, was traced to the lack of L-gulono-gamma-lactone oxidase, which catalyzes the terminal step in the biosynthesis of AscA. The non-functional GULOP was mapped to human chromosome 8p21 that corresponds to an evolutionarily conserved segment on either porcine chromosome 4 (SSC4) or 14 (SSC14). We investigated linkage between OD and SSC4- and 14-specific microsatellite loci in order to map the OD locus. Twenty-seven informative meioses in families from one sire and three dams revealed linkage of od with microsatellites SW857 and S0089, located in the subcentromeric region of SSC14. We isolated part of the GULO gene of the pig by screening a porcine genomic library using a pig GULO cDNA as a probe, and mapped it to SSC14q14 by fluorescence in situ hybridization (FISH). Thus, the porcine GULO gene is both a good physiological and positional candidate gene for vitamin C deficiency in pigs.


Asunto(s)
Deficiencia de Ácido Ascórbico/veterinaria , Deshidrogenasas del Alcohol de Azúcar/deficiencia , Deshidrogenasas del Alcohol de Azúcar/genética , Enfermedades de los Porcinos/enzimología , Enfermedades de los Porcinos/genética , Porcinos/genética , Porcinos/metabolismo , Animales , Deficiencia de Ácido Ascórbico/enzimología , Deficiencia de Ácido Ascórbico/genética , Secuencia de Bases , Evolución Biológica , Mapeo Cromosómico , Cartilla de ADN/genética , Ligamiento Genético , Biblioteca Genómica , Humanos , Hibridación Fluorescente in Situ , L-Gulonolactona Oxidasa , Repeticiones de Microsatélite
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