RESUMEN
Monolithic integration of control technologies for atomic systems is a promising route to the development of quantum computers and portable quantum sensors1-4. Trapped atomic ions form the basis of high-fidelity quantum information processors5,6 and high-accuracy optical clocks7. However, current implementations rely on free-space optics for ion control, which limits their portability and scalability. Here we demonstrate a surface-electrode ion-trap chip8,9 using integrated waveguides and grating couplers, which delivers all the wavelengths of light required for ionization, cooling, coherent operations and quantum state preparation and detection of Sr+ qubits. Laser light from violet to infrared is coupled onto the chip via an optical-fibre array, creating an inherently stable optical path, which we use to demonstrate qubit coherence that is resilient to platform vibrations. This demonstration of CMOS-compatible integrated photonic surface-trap fabrication, robust packaging and enhanced qubit coherence is a key advance in the development of portable trapped-ion quantum sensors and clocks, providing a way towards the complete, individual control of larger numbers of ions in quantum information processing systems.
RESUMEN
Each year, thousands of patients are at risk of cerebral ischemic injury, due to iatrogenic responses to surgical procedures. Prophylactic treatment of these patients as standard care could minimize potential neurological complications. We have shown that protection of brain tissue, in a non-human primate model of cerebral ischemic injury, is possible through pharmacological preconditioning using the immune activator D192935. We postulate that preconditioning with D192935 results in neuroprotective reprogramming that is evident in the brain following experimentally induced cerebral ischemia. We performed quantitative proteomic analysis of cerebral spinal fluid (CSF) collected post-stroke from our previously published efficacy study to determine whether CSF protein profiles correlated with induced protection. Four groups of animals were examined: naïve animals (no treatment or stroke); animals treated with vehicle prior to stroke; D192935 treated and stroked animals, further delineated into two groups, ones that were protected (small infarcts) and those that were not protected (large infarcts). We found that distinct protein clusters defined the protected and non-protected animal groups, with a 16-member cluster of proteins induced exclusively in D192935 protected animals. Seventy percent of the proteins induced in the protected animals have functions that would enhance neuroprotection and tissue repair, including several members associated with M2 macrophages, a macrophage phenotype shown to contribute to neuroprotection and repair during ischemic injury. These studies highlight the translational importance of CSF biomarkers in defining mechanism and monitoring responses to treatment in development of stroke therapeutics.
Asunto(s)
Isquemia Encefálica/líquido cefalorraquídeo , Isquemia Encefálica/prevención & control , Precondicionamiento Isquémico/métodos , Neuroprotección/fisiología , Proteómica/métodos , Animales , Isquemia Encefálica/patología , Macaca mulatta , Masculino , Neuroprotección/efectos de los fármacos , Receptor Toll-Like 9/agonistasRESUMEN
Between 10% and 40% of hospital-acquired infections have been attributed to cross-contamination of healthcare personnel hands. This study described frequency of hand hygiene within a fixed US military facility, in participants wearing a military uniform and hospital-provided scrubs. The median frequency of hand hygiene reported in both uniforms was 10 per hour. However, two-thirds of staff indicated that the military uniform decreased their ability to perform hand hygiene. Stakeholders should re-evaluate policies requiring wear of long-sleeved military uniforms by nursing staff to facilitate hand hygiene. Non-military facilities may also consider the impact of long-sleeved garments on hand hygiene.
Asunto(s)
Actitud del Personal de Salud , Vestuario , Higiene de las Manos/métodos , Control de Infecciones/métodos , Enfermeras y Enfermeros/psicología , Adulto , Femenino , Hospitales Militares , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
The hippocampus is critical to healthy cognition, yet results in the current study show that action video game players have reduced grey matter within the hippocampus. A subsequent randomised longitudinal training experiment demonstrated that first-person shooting games reduce grey matter within the hippocampus in participants using non-spatial memory strategies. Conversely, participants who use hippocampus-dependent spatial strategies showed increased grey matter in the hippocampus after training. A control group that trained on 3D-platform games displayed growth in either the hippocampus or the functionally connected entorhinal cortex. A third study replicated the effect of action video game training on grey matter in the hippocampus. These results show that video games can be beneficial or detrimental to the hippocampal system depending on the navigation strategy that a person employs and the genre of the game.
Asunto(s)
Cognición/efectos de la radiación , Hipocampo/fisiología , Juegos de Video/efectos adversos , Adulto , Cognición/fisiología , Corteza Entorrinal/fisiología , Corteza Entorrinal/efectos de la radiación , Femenino , Sustancia Gris/fisiopatología , Hipocampo/efectos de la radiación , Humanos , Masculino , Adulto JovenRESUMEN
BACKGROUND: A watertight dural repair is critical to minimizing the risk of postoperative complications secondary to cerebrospinal fluid (CSF) leaks. OBJECTIVE: To evaluate the safety and efficacy of a novel hydrogel, Adherus Dural Sealant, when compared with control, DuraSeal Dural Sealant System, as an adjunct to standard methods of dural repair. METHODS: In this 17-center, prospective, randomized clinical trial designed as a noninferiority, single-blinded study, 124 patients received Adherus Dural Sealant (test sealant) and 126 received DuraSeal (control). The primary composite endpoint was the proportion of patients who were free of any intraoperative CSF leakage during Valsalva maneuver after dural repair, CSF leak/pseudomeningocele, and unplanned retreatment of the surgical site. Each component was then analyzed individually as a secondary endpoint. Patients were followed for 4 mo after surgery. RESULTS: The primary composite endpoint at the 120-d follow-up was achieved in 91.2% of the test sealant group compared with 90.6% of the control, thus showing that the test sealant was statistically significantly noninferior to DuraSeal ( P = .0049). Post hoc analysis of the primary composite endpoint at 14 d demonstrated superiority of the test sealant over the control ( P = .030). Primary endpoint failures in the control group tended to occur early in follow-up period, while a majority of test dural sealant failures were identified through protocol-required radiographic imaging at the 120-d follow-up visit. CONCLUSION: The test sealant, Adherus Dural Sealant, is a practical, safe, and effective adjunct to achieving a watertight dural closure after primary dural closure in cranial procedures.
Asunto(s)
Pérdida de Líquido Cefalorraquídeo/terapia , Duramadre/fisiología , Hidrogeles/uso terapéutico , Adhesivos Tisulares/uso terapéutico , Resultado del Tratamiento , Adulto , Anciano , Pérdida de Líquido Cefalorraquídeo/diagnóstico por imagen , Duramadre/cirugía , Femenino , Estudios de Seguimiento , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos , Estados Unidos , Maniobra de Valsalva , Adulto JovenRESUMEN
Ischemia-reperfusion brain injury can be iatrogenically induced secondary to life-saving procedures. Prophylactic treatment of these patients offers a promising prevention for lifelong complications. We postulate that a cytosine-guanine (CpG) oligodeoxynucleotide (ODN) can provide robust antecedent protection against cerebral ischemic injury with minimal release of pro-inflammatory cytokines, making it an ideal candidate for further clinical development. Mouse and nonhuman primate (NHP) models of cerebral ischemic injury were used to test whether an A-type CpG ODN, which induces minimal systemic inflammatory cytokine responses, can provide prophylactic protection. Extent of injury in the mouse was measured by histological staining of live tissue. In the NHP, injury was assessed 2 and 7 days post-occlusion from T2-weighted magnetic resonance images and neurological and motor deficits were cataloged daily. Plasma cytokine levels were measured using species-specific Luminex assays. Prophylactic administration of an A-type CpG ODN provided robust protection against cerebral ischemic injury in the mouse with minimal systemic inflammation. Rhesus macaques treated with D192935, a mixture of human optimized A-type CpG ODNs, had smaller infarcts and demonstrated significantly less neurological and motor deficits following ischemic injury. Our findings demonstrate the translational potential of D192935 as a prophylactic treatment for patients at risk of cerebral ischemic injury.
Asunto(s)
Isquemia Encefálica/prevención & control , Citocinas/metabolismo , Evaluación Preclínica de Medicamentos , Fármacos Neuroprotectores/uso terapéutico , Oligodesoxirribonucleótidos/uso terapéutico , Daño por Reperfusión/prevención & control , Análisis de Varianza , Animales , Infarto Encefálico/diagnóstico por imagen , Infarto Encefálico/tratamiento farmacológico , Infarto Encefálico/etiología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Macaca mulatta , Masculino , Ratones , Ratones Endogámicos C57BL , Examen Neurológico , Fármacos Neuroprotectores/química , Oligodesoxirribonucleótidos/química , Condicionamiento Físico Animal/fisiología , Daño por Reperfusión/complicaciones , Factores de TiempoRESUMEN
Chemical-vapor-deposited (CVD) ZnS is an example of a polycrystalline material that is difficult to polish smoothly via the magnetorheological finishing (MRF) technique. When MRF-polished, the internal infrastructure of the material tends to manifest on the surface as millimeter-sized "pebbles," and the surface roughness observed is considerably high. The fluid's parameters important to developing a magnetorheological (MR) fluid that is capable of polishing CVD ZnS smoothly were previously discussed and presented. These parameters were acidic pH (â¼4.5) and low viscosity (â¼47 cP). MRF with such a unique MR fluid was shown to reduce surface artifacts in the form of pebbles; however, surface microroughness was still relatively high because of the absence of a polishing abrasive in the formulation. In this study, we examine the effect of two polishing abrasives-alumina and nanodiamond-on the surface finish of several CVD ZnS substrates, and on other important IR polycrystalline materials that were finished with acidic MR fluids containing these two polishing abrasives. Surface microroughness results obtained were as low as â¼28 nm peak-to-valley and â¼6-nm root mean square.
RESUMEN
In this Letter we report the experimental demonstration of a new temporal shaping technique for x-ray free-electron lasers (FELs). This technique is based on the use of a spectrally shaped infrared (IR) laser and allows optical control of the x-ray generation process. By accurately manipulating the spectral amplitude and phase of the IR laser, we can selectively modify the electron bunch longitudinal emittance thus controlling the duration of the resulting x-ray pulse down to the femtosecond time scale. Unlike other methods currently in use, optical shaping is directly applicable to the next generation of high-average power x-ray FELs such as the Linac Coherent Light Source-II or the European X-FEL, and it enables pulse shaping of FELs at the highest repetition rates. Furthermore, this laser-shaping technique paves the way for flexible tailoring of complex multicolor FEL pulse patterns required for nonlinear multidimensional x-ray spectroscopy as well as novel multicolor diffraction imaging schemes.
RESUMEN
Methamphetamine is a potent psychostimulant drug of abuse that increases release and blocks reuptake of dopamine, producing intense euphoria, factors that may contribute to its widespread abuse. It also produces severe neurotoxicity resulting from oxidative stress, DNA damage, blood-brain barrier disruption, microgliosis, and mitochondrial dysfunction. Intracerebral hemorrhagic and ischemic stroke have been reported after intravenous and oral abuse of methamphetamine. Several studies have shown that methamphetamine causes vasoconstriction of vessels. This study investigates the effect of methamphetamine on endothelin-1 (ET-1) release in mouse brain endothelial cells by ELISA. ET-1 transcription as well as endothelial nitric oxide synthase (eNOS) activation and transcription were measured following methamphetamine treatment. We also examine the effect of methamphetamine on isolated cerebral arteriolar vessels from C57BL/6 mice. Penetrating middle cerebral arterioles were cannulated at both ends with a micropipette system. Methamphetamine was applied extraluminally, and the vascular response was investigated. Methamphetamine treatment of mouse brain endothelial cells resulted in ET-1 release and a transient increase in ET-1 message. The activity and transcription of eNOS were only slightly enhanced after 24 hr of treatment with methamphetamine. In addition, methamphetamine caused significant vasoconstriction of isolated mouse intracerebral arterioles. The vasoconstrictive effect of methamphetamine was attenuated by coapplication of the endothelin receptor antagonist PD145065. These findings suggest that vasoconstriction induced by methamphetamine is mediated through the endothelin receptor and may involve an endothelin-dependent pathway.
Asunto(s)
Estimulantes del Sistema Nervioso Central/farmacología , Endotelina-1/metabolismo , Endotelio/efectos de los fármacos , Metanfetamina/farmacología , Análisis de Varianza , Animales , Arterias/efectos de los fármacos , Encéfalo/citología , Línea Celular Transformada , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Endotelina-1/antagonistas & inhibidores , Endotelina-1/genética , Ensayo de Inmunoadsorción Enzimática , Ratones , Ratones Endogámicos C57BL , Óxido Nítrico Sintasa de Tipo III/metabolismo , Oligopéptidos/farmacología , ARN Mensajero/metabolismo , Factores de Tiempo , Vasoconstricción/efectos de los fármacosRESUMEN
OBJECTIVE: To assess the management of acute stroke on Montserrat over a sixteen (16) year period in order to highlight areas in which the quality of the service provided can be improved.DESIGN AND METHODS: Forty five patients were studied from a sample frame of 117. Mean age 70 (range 38-100) of whom 29 (64%) were male. A data collection sheet was designed. Information was collected on areas of patient management. Logrank and Cox regression methods were used to test association between survival after stroke and other independent factors. RESULTS: Only 7% of patients (3) had a CT scan. All 3 had the scan within 24 hours. 49% of patients received Aspirin without a CT Diagnosis. Having Glasgow Coma Scale (GCS) <13 (p <0.001), papilledema or neck stiffness (p = 0.003), receiving oxygen for having an oxygen saturation <95% (p = 0.041) and having a swallow assessment (p<0.001) were negatively associated with survival. The estimated median survival time was 1.1 years. CONCLUSION: Access to CT scanning was a problem for patients with acute stroke on Montserrat. Providing CT scanning locally would allow for long term cost reductions and is likely to reduce morbidity and mortality from stroke. This, in combination with Stoke-unit quality ward care, may improve the median survival time.
Asunto(s)
Accidente Cerebrovascular , Manejo de la Enfermedad , Indias OccidentalesRESUMEN
Post-harvest storage is largely limited by fruit softening, a result of cell wall degradation. Pectin methylesterase (PE) (EC 3.1.1.11) is a major hydrolase responsible for pectin de-esterification in the cell wall, a response to fruit ripening. Two major PE isoforms, PE1 and PE2, have been isolated from tomato (Solanum lycopersicon) pericarp tissue and both have previously been down-regulated using antisense suppression. In this paper, PE1 and PE2 double antisense tomato plants were successfully generated through crossing the two single antisense lines. In the double antisense fruit, approximately 10% of normal PE activity remained and ripening associated pectin de-esterification was almost completely blocked. However, double antisense fruit softened normally during ripening. In tomato fruit, the PE1 isoform was found to contribute little to total PE activity and have little effect on the degree of esterification of pectin. In contrast, the other dominant fruit isoform, PE2, has a major impact on de-esterification of total pectin. PE2 appears to act on non-CDTA-soluble pectin during ripening and on CDTA-soluble pectin before the start of ripening in a potentially block-wise fashion.
Asunto(s)
Hidrolasas de Éster Carboxílico/metabolismo , Frutas/enzimología , Regulación de la Expresión Génica de las Plantas , Pectinas/metabolismo , Solanum lycopersicum/enzimología , Hidrolasas de Éster Carboxílico/genética , Pared Celular/metabolismo , Regulación hacia Abajo , Frutas/genética , Frutas/crecimiento & desarrollo , Expresión Génica , Regulación Enzimológica de la Expresión Génica , Silenciador del Gen , Isoenzimas/metabolismo , Solanum lycopersicum/genética , Solanum lycopersicum/crecimiento & desarrollo , Plantas Modificadas Genéticamente , Ácidos Urónicos/análisis , Ácidos Urónicos/metabolismoRESUMEN
Multiple three-dimensional reconstructions of a γ/γ' phase structure in Alloy 720Li have been carried out by employing a serial milling technique with simultaneous electron backscatter diffraction (EBSD) and energy dispersive x-ray (EDX) analysis data collection. Combining EBSD data with EDX is critical in obtaining maps to distinguish between the chemically differing, but crystallographically similar γ and γ' phases present in the alloy studied. EDX is shown to allow the differentiation of γ and γ' phases, with EBSD providing increased grain shape accuracy. The combination of data sources also allowed identification of coherent γ/γ' phase interfaces that would not be identified using solely EBSD or EDX. The study identifies a region of grain banding within the alloy, which provides the basis for a three-dimensional comparison and discussion of γ' phase size between coarse and fine grain regions, whilst also identifying coherent γ' phase interfaces, possible only using both EDX and EBSD systems simultaneously. The majority of the γ' phase lies in the range of 1-10 µm in non-banded regions, with a detectable particle size limit of 500 nm being established. The validity of the reconstruction has been demonstrated using an electron interaction volumes model, and an assessment of the validity of EBSD and EDX data sources is discussed showing γ' phase connectivity in all dimensions.
RESUMEN
The use of accelerometry to monitor activity in human stroke patients has revealed strong correlations between objective activity measurements and subjective neurological findings. The goal of our study was to assess the applicability of accelerometry-based measurements in experimental animals undergoing surgically-induced cerebral ischemia. Using a nonhuman primate cortical stroke model, we demonstrate for the first time that monitoring locomotor activity prior to and following cerebrovascular ischemic injury using an accelerometer is feasible in adult male rhesus macaques and that the measured activity outcomes significantly correlate with severity of brain injury. The use of accelerometry as an unobtrusive, objective preclinical efficacy determinant could complement standard practices involving subjective neurological scoring and magnetic resonance imaging in nonhuman primates. Similar activity monitoring devices to those employed in this study are currently in use in human clinical studies, underscoring the feasibility of this approach for assessing the clinical potential of novel treatments for cerebral ischemia.
RESUMEN
Cerebral ischemic injury is a significant portion of the burden of disease in developed countries; rates of mortality are high and the costs associated with morbidity are enormous. Recent therapeutic approaches have aimed at mitigating the extent of damage and/or promoting repair once injury has occurred. Often, patients at high risk of ischemic injury can be identified in advance and targeted for antecedent neuroprotective therapy. Agents that stimulate the innate pattern recognition receptor, Toll-like receptor 9, have been shown to induce tolerance (precondition) to ischemic brain injury in a mouse model of stroke. Here, we demonstrate for the first time that pharmacological preconditioning against cerebrovascular ischemic injury is also possible in a nonhuman primate model of stroke in the rhesus macaque. The model of stroke used is a minimally invasive transient vascular occlusion, resulting in brain damage that is primarily localized to the cortex and as such, represents a model with substantial clinical relevance. Finally, K-type (also referred to as B-type) cytosine-guanine-rich DNA oligonucleotides, the class of agents employed in this study, are currently in use in human clinical trials, underscoring the feasibility of this treatment in patients at risk of cerebral ischemia.
Asunto(s)
Precondicionamiento Isquémico/métodos , Oligodesoxirribonucleótidos/uso terapéutico , Accidente Cerebrovascular/prevención & control , Receptores Toll-Like/agonistas , Animales , ADN/uso terapéutico , Modelos Animales de Enfermedad , Macaca mulatta , Masculino , Ratones , Ratones Endogámicos C57BL , Recuperación de la Función/efectos de los fármacos , Accidente Cerebrovascular/patologíaRESUMEN
Post operative cognitive dysfunction (POCD) is common following lower limb arthroplasty. The prevalence varies from 41-75% at 7 days to 18-45% at 3 months post operatively. The wide range of prevalence is due to inconsistencies in defining and quantifying POCD. The aim of this study is to ascertain an accurate prevalence of POCD in patients who had either conventional TKR (n=31) or computer-assisted TKR (n=30). Cognition was assessed pre-operatively, 6 days and at 6 months post-operatively by a battery of 11 validated neuropsychological tests. We found the mean prevalence of POCD to be 72% at 6 days and 30% at 6 months post-operatively. When comparing the prevalence of POCD between the two groups, we found no statistically significant difference at 6 days or at 6 months post-operatively. The only statistically significant factor between the two groups was the mean procedure time which was longer in the computer-assisted TKR group (p=< 0.001). We found a correlation between procedure time and the prevalence of POCD at 6 days (p=0.02) but not 6 months (p=0.26). POCD occurs in approximately one-third of TKR patients at 6 months post-operatively. The cause is undoubtedly multi-factorial; however we have demonstrated that procedure time may be a contributing factor. Our results suggest that using an intra-medullary femoral jig has no effect on POCD. Further research into the cognitive effects following TKR with and without a tourniquet would be of benefit.
Asunto(s)
Artroplastia de Reemplazo de Rodilla/psicología , Trastornos del Conocimiento/epidemiología , Complicaciones Posoperatorias , Cirugía Asistida por Computador/métodos , Adulto , Anciano , Anciano de 80 o más Años , Artroplastia de Reemplazo de Rodilla/efectos adversos , Artroplastia de Reemplazo de Rodilla/métodos , Trastornos del Conocimiento/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Australia del Sur/epidemiología , Cirugía Asistida por Computador/efectos adversos , Factores de TiempoRESUMEN
Information regarding the reproductive biology of black-footed cats (BFC) and sand cats (SC) is extremely limited. Our objectives were to: (1) validate fecal hormone analysis (estrogens, E; progestagens, P; androgens, T) for noninvasive monitoring of gonadal activity; (2) characterize estrous cyclicity, ovulatory mechanisms, gestation, and seasonality; and (3) evaluate male reproductive activity via fecal androgen metabolites and ejaculate traits. In both species, the estrous cycle averaged 11-12 days. In BFC (n=8), estrus lasted 2.2+/-0.2 days with peak concentrations of E (2962.8+/-166.3 ng/g feces) increasing 2.7-fold above basal concentrations. In SC (n=6), peak concentrations of E (1669.9+/-83.5 ng/g feces) during estrus (2.9+/-0.2 days) were 4.0-fold higher than basal concentrations. Nonpregnant luteal phases occurred in 26.5% (26 of 98) of BFC estrous cycles, but were not observed in SC (0 of 109 cycles). In both species, P concentrations during pregnancy were elevated (32.3+/-3.0 microg/g feces BFC; 8.5+/-0.7 microg/g feces SC) approximately 10-fold above basal concentrations. Fecal T concentrations in males averaged 3.1+/-0.1 microg/g feces in BFC and 2.3+/-0.0 microg/g feces in SC. Following electroejaculation, 200 to 250 microl of semen was collected containing 29.9 (BFC) to 36.5 (SC)x10(6) spermatozoa with 40.4 (SC) to 46.8 (BFC)% normal morphology. All females exhibited estrous cycles during the study and spermatozoa were recovered from all males on every collection attempt, suggesting poor reproductive success in these species may not be due to physiological infertility.
Asunto(s)
Andrógenos/metabolismo , Gatos/fisiología , Estrógenos/metabolismo , Heces/química , Progestinas/metabolismo , Semen/metabolismo , Animales , Gatos/metabolismo , Femenino , Regulación del Desarrollo de la Expresión Génica , Técnicas para Inmunoenzimas , Masculino , Ovulación/metabolismo , Embarazo , Semen/químicaRESUMEN
Studies of in vitro fertilization (IVF) and sperm cryopreservation have been conducted in several small cat species, but virtually no data exist for black-footed cats (Felis nigripes) (BFCs) or sand cats (Felis margarita) (SCs). The objectives of this study were 1) to compare in vitro motility and acrosome status of fresh and cryopreserved (frozen in pellets on dry ice or in straws in liquid nitrogen vapor) BFC and SC spermatozoa cultured in feline-optimized culture medium (FOCM) or Ham F-10, 2) to assess ovarian responsiveness in BFCs and SCs following exogenous gonadotropin treatment and laparoscopic oocyte recovery, and 3) to evaluate the fertility of fresh and frozen-thawed spermatozoa from both species using homologous and heterologous (domestic cat oocytes) IVF in the two culture media. Motility and acrosomal integrity of fresh and frozen-thawed spermatozoa from BFCs and SCs were similar (P > 0.05) in both media during 6 h of culture. Although effects were more pronounced in SCs, cryopreservation in straws was superior (P < 0.05) to cryopreservation in pellets for both species. Gonadotropin stimulation produced approximately 16 ovarian follicles per female, and >80% of recovered oocytes were of optimal (grade 1) quality. The BFC and SC spermatozoa fertilized 60.0%-79.4% of homologous and 37.7%-42.7% of heterologous oocytes in both culture media, with increased (P < 0.05) cleavage of homologous (SC) and heterologous (BFC and SC) oocytes in FOCM. These results provide the first information to date on the gamete biology of two imperiled cat species and further our capacity to apply reproductive technologies for their conservation.
Asunto(s)
Criopreservación/métodos , Felis , Fertilización In Vitro/métodos , Preservación de Semen/métodos , Animales , Gatos , Células Cultivadas , Criopreservación/veterinaria , Técnicas de Cultivo de Embriones , Felis/fisiología , Femenino , Fertilización In Vitro/veterinaria , Masculino , Recuperación del Oocito/métodos , Recuperación del Oocito/veterinaria , Embarazo , Análisis de Semen , Preservación de Semen/veterinaria , Recuperación de la Esperma/veterinaria , Espermatozoides/citología , Espermatozoides/fisiologíaRESUMEN
OBJECTIVE: Primary closure of the dura remains difficult in many neurosurgical cases. One option for dural grafting is the collagen sponge, which is available in multiple forms, namely, monolayer collagen and bilayer collagen. Our primary goal was to assess differences in the incidence of postoperative cerebrospinal fluid (CSF) leak, including fistula and pseudomeningocele, and postoperative infection between monolayer collagen and bilayer collagen grafts. METHODS: A single-center retrospective analysis of 475 consecutive neurosurgical procedures was performed. Primary endpoints were CSF leak and infection, adjusting for the impact of additional nonautologous materials. Multivariate regression analysis was used to identify predictors of postoperative CSF leak and infection. RESULTS: The overall frequency of postoperative CSF leak was 6.7%. There was no significant difference in the incidence of CSF leak based on the type of collagen sponge (monolayer versus bilayer) used (5.5% versus 7.5%, respectively; P = 0.38). The overall frequency of postoperative infection was 4.2%. There was no significant difference in the incidence of infection between groups (4.9% versus 3.8%; P = 0.54). Bilayer sponges were associated with a significantly lower incidence of CSF leak than monolayer sponges (odds ratio, 0.09; 95% confidence interval, 0.01-0.73). CONCLUSION: Bilayer collagen sponges are associated with a reduction in postoperative CSF leak, notably in posterior fossa surgery. The need for additional non-native materials is predictive of postoperative CSF leak, along with location and type of procedure. Intrinsic patient characteristics (e.g., age, diabetes, smoking) do not seem to affect the efficacy of collagen sponge dural grafts.
Asunto(s)
Materiales Biocompatibles/uso terapéutico , Colágeno/uso terapéutico , Craneotomía/efectos adversos , Duramadre/cirugía , Complicaciones Posoperatorias/prevención & control , Efusión Subdural/prevención & control , Animales , Bovinos , Humanos , Estudios Retrospectivos , Efusión Subdural/etiologíaRESUMEN
The long-standing controversy regarding the late Pleistocene megafaunal extinctions in North America has been invigorated by a hypothesis implicating a cosmic impact at the Allerød-Younger Dryas boundary or YDB (approximately 12,900 +/- 100 cal BP or 10,900 +/- 100 (14)C years). Abrupt ecosystem disruption caused by this event may have triggered the megafaunal extinctions, along with reductions in other animal populations, including humans. The hypothesis remains controversial due to absence of shocked minerals, tektites, and impact craters. Here, we report the presence of shock-synthesized hexagonal nanodiamonds (lonsdaleite) in YDB sediments dating to approximately 12,950 +/- 50 cal BP at Arlington Canyon, Santa Rosa Island, California. Lonsdaleite is known on Earth only in meteorites and impact craters, and its presence strongly supports a cosmic impact event, further strengthened by its co-occurrence with other nanometer-sized diamond polymorphs (n-diamonds and cubics). These shock-synthesized diamonds are also associated with proxies indicating major biomass burning (charcoal, carbon spherules, and soot). This biomass burning at the Younger Dryas (YD) onset is regional in extent, based on evidence from adjacent Santa Barbara Basin and coeval with broader continent-wide biomass burning. Biomass burning also coincides with abrupt sediment mass wasting and ecological disruption and the last known occurrence of pygmy mammoths (Mammuthus exilis) on the Channel Islands, correlating with broader animal extinctions throughout North America. The only previously known co-occurrence of nanodiamonds, soot, and extinction is the Cretaceous-Tertiary (K/T) impact layer. These data are consistent with abrupt ecosystem change and megafaunal extinction possibly triggered by a cosmic impact over North America at approximately 12,900 +/- 100 cal BP.